**Chapter 5**

*Pneumothorax*

1998;**116**:872-873

2010;**17**:593-599

2006;**355**:e9

2011;**21**:e81-ee3

2008;**56**:374-375

[52] Fonseca P. Catamenial pneumothorax: A multifactorial etiology. The Journal of Thoracic and Cardiovascular Surgery.

[53] Kumakiri J, Kumakiri Y, Miyamoto H, et al. Gynecologic evaluation of catamenial pneumothorax associated with endometriosis. Journal of Minimally Invasive Gynecology.

[54] Kronauer CM. Images in clinical medicine. Catamenial pneumothorax. The New England Journal of Medicine.

[55] Baysungur V, Tezel C, Okur E, Yilmaz B. Recurrent pneumothorax diagnosed as catamenial after

[56] Mikroulis DA, Didilis VN, Konstantinou F, et al. Catamenial pneumothorax. The Thoracic and Cardiovascular Surgeon.

videothoracoscopic examination of the pleural cavity. Surgical Laparoscopy, Endoscopy & Percutaneous Techniques.

**54**


**Abstract**

Chalcogenide thin films have attracted a great deal of attention for decades because of their unique properties. The recent developments on thin film-based supercapacitor applications were reported. As a result of sustained efforts, the experimental findings revealed remarkable properties with enhanced fabrication methods. The properties of perovskite solar cells were discussed in terms of crystal structure and phase transition, electronic structure, optical properties, and electrical properties. Perovskite solar cell has gained attention due to its high absorption coefficient with a sharp absorption edge, high photoluminescence quantum yield, long charge carrier diffusion lengths, large mobility, high defect tolerance, and low surface recombination velocity. The thin film-based gas sensors are used for equally the identification and quantification of gases, and hence should be both selective and sensitive to a required target gas in a mixture of gases. Metal chalcogenide materials are considered excellent absorber materials in photovoltaic cell applications. These materials exhibited excellent absorption coefficient and suitable band gap value to absorb the maximum number of photons from sun radiation. The photovoltaic parameters were strongly dependent on various experimental conditions.

**Keywords:** thin films, semiconductor, band gap, solar cells, sensor, chalcogenide materials, supercapacitor, power conversion efficiency


**5. Conclusion**

During the pandemic situation, online teaching-learning was initiated using various formats and many types of interfaces were used to deliver the content. A newnorm of online education is being delivered in the hybrid mode in many institutes, with a fraction of the students attending F2F being present in the campus and the remaining students attending online. Both online learning administered through the LMS in blended mode and hybrid learning have been accepted in most of the parts of the world to deal with the pandemic and to continue with the academic progress of the students. Educators need to meet the needs of the diverse learners and design the online learning experiences towards promoting a learning environment which should encourage engagement, promote interaction, motivate learners, and above all should facilitate learning both on campus and off-campus. Preparing web-based learning resources and administering online synchronous and asynchronous teaching require a great time and use of substantial resources. Educational institutes should invest on a sustainable information technology infrastructure that can support both the online resources and web-conferencing tools. The administrators should plan the budget for maintenance of cloud-based IT servers along with a stable LMS, suitable set of technological products, e-learning tools and a team of instructional designers, multi-media designers, content developers and web application programmer to run the online learning infrastructure. However, without a planned faculty development exercise aiming at educating the faculty in online learning pedagogy, instructional

*New Updates in Online Learning DOI: http://dx.doi.org/10.5772/intechopen.102576*

design skills and design of online learning activities, presence of technology alone will not ensure effective and engaging online learning capable of attaining the educational goals.


**6. Designed phantom**

The majority of the commercially available phantoms are of homogeneous density, whereas the actual human body is a complex medium of different density patterns [14]. Additionally, the very few heterogeneous phantoms, which are available commercially (e.g. anthropomorphic phantom) are very costly and are not procured by most radiotherapy centers, especially in developing countries. It is known that human body is composed of fat, tissue, bones, and air cavities having different electron densities that influence the interaction of photon and electron energy deposition affecting the dose delivery to a target volume. Therefore, this study was conducted to develop an indigenous heterogeneous pelvic phantom similar to the patient's anatomy and perform a pretreatment verification in a realistic clinical scenario to obtain reproducible dosimetry.


**7. Modulation of oxidative stress**

EOCs, and in 50% of clear cell carcinomas, but not in mucinous ovarian carcinomas [61]. Thus, HE4 was identified as one of the most useful biomarkers for ovarian cancer, although it lacked tissue-specificity [60, 62–64]. Secreted HE4 high levels were also detected in the serum of ovarian cancer patients [65]. Additionally, combining CA-125 and HE4 is a more accurate

Multi-marker panels have the potential for high positive predictive values (PPVs), but careful validation with appropriate sample cohorts is mandatory and complex algorithms may be difficult to implement for routine clinical use [59]. Panels of biomarkers have been extensively investigated to improve sensitivity and specificity and have included some of the most promising reported markers such as CA72–4, M-CSF, OVX1, LPA, prostacin, osteopontin, inhibin and kallikrein [69–71]. However, most of these tests frequently require certain equipments and complex computational algorithms that may not be available in a standard immunoassay laboratory, [32]. Among postmenopausal women in the U.S., only 1 in 2500 women are reported with ovarian cancer. Due to this low prevalence of the disease, a screening method that yield a 75% sensitivity and 99.6% specificity to achieve a PPV value of 10% to be effective for the detection of all stages of ovarian cancer [72]. To date, there is no single biomarker avail-

The established role of MPO in oxidative stress and inflammation has been a leading factor in the study of MPO as a possible marker of plaque instability and a useful clinical tool in the evaluation of patients with coronary heart disease [73]. Recent genetic studies implicated MPO in the development of lung cancer by demonstrating a striking correlation between the relative risk for development of the disease and the incidence of functionally distinct MPO polymorphisms [74]. Myeloperoxidase levels reported for various inflammatory disorders are coincidentally lower than those levels found in all stages of ovarian cancer. A previous study reported normal serum MPO and iron levels as 62 ± 11 ng/ml and 96 ± 9 μg/dl, respectively [75]. However, there was a significant increase in serum MPO and iron levels to 95 ± 20 ng/ml and 159 ± 20 μg/dl, respectively, in asthmatic individuals [75]. Although there was an increase in this reported serum iron, these levels still fell within the normal range (50 to 170 μg/dl) [22, 75]. Other studies have showed that an elevated MPO levels, reaching up to 350 ng/ml, in serum plasma, was indicative of a higher risk for cardiovascular events in patients hospitalized for chest pain [76, 77]. A recent study showed a significant correlation between MPO levels and the stage of ovarian cancer, as is the linear trend for MPO with increasing stage [22]. Similarly, there was a significant difference in the level of free iron in serum and tissues obtained from stage I as compared to combined stages II, III, and IV ovarian cancer. There was an overlap between stage I ovarian cancer and inflammation (endometriosis) serum MPO levels, however serum free iron levels were significantly higher in stage I ovarian cancer as compared to inflammation. There was no significant change in free iron levels between the healthy control group, benign gynecologic conditions group, and inflammation group [22].

Due to the overlap of MPO levels in early-stage ovarian cancer and inflammatory conditions, there is a potential for a false positive with MPO alone in patients with cardiovascular, inflammation, and/or asthmatic disorders. It has been reported that MPO heme destruction and iron release is mediated by high levels of both HOCl (a product of MPO) and oxidative stress (i.e. cancer) [22]. The free iron generated by hemoprotein destruction not only contributes to elevation of

predictor of malignancy than either alone [66–68].

90 Ovarian Cancer - From Pathogenesis to Treatment

able that met these requirements.

Several studies have reported the beneficial effects of modulating the redox status of cancer cells, however few studies have been reported for ovarian cancer [90–92]. Inhibition of prooxidant enzymes, such as NAD(P)H oxidase, has been shown to significantly induce apoptosis of cancer cells [93, 94]. We investigated whether NAD(P)H oxidase-mediated generation of intracellular reactive ROS lead to anti-apoptotic activity and thus a growth advantage to EOC cells. Diphenyleneiodonium (DPI) has been used to inhibit ROS production mediated by NAD(P)H oxidase in various cell types [95–97]. Our results showed that NAD(P)H oxidase is over-expressed in EOC tissues and cells as compared to normal ovarian tissues and cells [52]. Indeed, high levels of NAD(P)H oxidase are known to promote tumorigenesis of NIH3T3 mouse fibroblasts and the DU-145 prostate epithelial cells [98].

Inhibition of NAD(P)H oxidase has also been reported to decrease the generation of O2 ●–, H2 O2 , as well as other oxidants [93, 94]. Cancer cells are known to manifest enhanced intrinsic oxidative stress and metabolic activity that lead to mitochondrial failure [99, 100]. Indeed, it was previously reported that ovarian tumors are characterized by increased ROS levels as evident from increased O2 **●–** generated from NAD(P)H oxidase as well as mitochondrial malfunction [101]. The NAD(P)H oxidase redox signaling is controlled by mitochondria, and thus loss of this control is thought to contribute to tumorigenesis [101]. Others have also shown that inhibition of NAD(P)H oxidase induced apoptosis in cancer cells [102]. Continuous ROS production by the cell and the environment further induces the inhibition of phosphorylation of AKT and subsequent suppression of AKT-mediated phosphorylation of ASK1 on Ser-83, resulting in significant decrease in apoptosis [102–104]. Furthermore, paclitaxel, a chemotherapeutic agent used in the treatment of ovarian cancer and other cancers, induced apoptosis of ovarian cancer cells by negative regulation of AKT–ASK1 phosphorylation signaling [102–104]. On the other hand, activation of AKT by ROS provided protection against apoptosis [102–104].

ATP, cancer cells significantly increase glucose uptake through upregulation of glucose receptors [40, 41, 118]. Increased lactate in cancer cells enhances lactic acidosis, which is significantly toxic to the surrounding tissues and can facilitate tumor growth through the stimulation of ECM degradation, angiogenesis, and metastasis [118]. Additionally, aerobic glycolysis in cancer cells activates HIF, an oxygen-sensitive transcription factor that plays an important role in initiation and maintenance of the oncogenic phenotype [118]. In this regard, HIF induces the expression of several glucose transporters and glycolysis enzymes as well as induces the expression of pyruvate dehydrogenate kinase (PDK), an enzyme that stimulates pyruvate entry into the mitochondria for oxidation [41, 118, 119]. Thus, shifting glucose metabolism in cancer cells from glycolysis to glucose oxidation may have therapeutic value [120]. Indeed, inhibiting PDK by dichloroacetate (DCA) has been reported to induce apoptosis in tumor cells and significantly decreased HIF-1α expression [40]. More importantly DCA is currently in the clinical use for the treatment of hereditary mitochondrial diseases as well as lactic acidosis [41, 121]. The use of DCA at a dose of 35 to 50 mg/kg decreased lactate levels by more than 60% [41, 122]. Dichloroacetate treatment has been shown to significantly induce apoptosis, through the stimulation of caspase-3 activity, in a dose-dependent manner in EOC cells as well as other cancers, such as glioblastoma, endometrial, prostate, and non-small cell lung cancers [40, 123]. Aerobic glycolysis is associated with resistance to apoptosis in cancer cells as many of the enzymes in the glycolysis process are known to modulate gene transcription of apoptotic proteins [40, 41, 69, 124]. Stimulation of pyruvate entry into the mitochondria by DCA, through activation of PDH and inhibition of PDK, is an ideal method to shift aerobic glycolysis to glucose oxidation as inhibiting aerobic glycolysis results in ATP depletion and necrosis, not apoptosis [41, 125].

New Insights into the Pathogenesis of Ovarian Cancer: Oxidative Stress

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An additional approach to induce apoptosis in cancer cells is through scavenging high levels of oxidants produced by cancer cells utilizing antioxidants [126]. Deficiency in SOD or inhibi-

toxic free radicals that are critical to the oncogenic process [127]. Elevated levels of oxidants and free radicals are also known to induce cellular senescence and necrosis, and thus can kill tumor cells [40, 128]. The precise effect of high levels of oxidants and free radicals in cancer cells will depend on the type of cells and tissues, the site of production, and the type and

**9. Chemotherapy and the acquisition of chemoresistance in EOC cells**

Resistance to taxanes and platinums, chemotherapy drugs in current use for ovarian cancer treatment, remains a major obstacle to a successful treatment of ovarian cancer patients [6]. Resistance to chemotherapy not only limits the use of the initial drug but also limits the use of other agents, even those with different mechanisms of action [129]. Chemotherapy drugs exert their actions by the initiation of cell death either directly through the generation of oxidative stress or as an indirect effect of exposure, as observed with several chemotherapeutic agents [130]. The development of chemoresistance to drugs is dependent on several factors that include: influx/efflux of drugs that decrease platinum accumulation in tumor cells, enhanced GSH and GST levels, upregulation of anti-apoptotic proteins such as Bcl-2, loss of tumor necrosis factor receptor ligand which induces apoptosis, increased DNA repair through up-regulation of repair

•− which is the precursor for several

tion of SOD enzyme activity causes accumulation of O2

concentration of oxidants [13].

Data from our laboratory clearly demonstrated that treatment of EOC cells with DPI, which inhibits ROS production mediated by NAD(P)H oxidase, significantly reduced SOD3 and HIF-1α mRNA and protein levels as early as 30 minutes after treatment with a concomitant increase in apoptosis [52]. The association between increased HIF-1α expression and decreased cellular apoptosis has also been demonstrated in lung and hepatoma cancer cells [94, 105]. Overexpression of HIF-1α is thought to decrease apoptosis by the upregulation of anti-apoptotic proteins, Bcl-2 and Bcl-xL and down regulation of pro-apoptotic proteins, BAX and BAK [106]. Inhibition of HIF-1α by rapamycin increased apoptosis by decreasing the expression of apoptosis inhibitor Bcl-2 in ovarian cancer xenografts [107]. Additionally, inhibition of HIF-1α by rapamycin enhanced apoptosis through the inhibition of cell survival signals in several other cell lines [107].

Most of the NAD(P)H oxidase-generated O2 ●– is utilized to produce H2 O2 by nonenzymatic or SOD-catalyzed reactions [108–110]. Hydrogen peroxide serves as the precursor of more toxic hydroxyl radicals and thus is extremely destructive to cells and tissues [109–111]. The expression of SOD3 was reported to increase in response to intrinsic oxidative stress in ovarian cancer cells [112]. It has been demonstrated that overexpression of the SOD3 gene significantly suppressed lung cancer metastasis as well as inhibited the growth of B16-F1 melanoma tumors in mice [113, 114]. However, in a somewhat controversial study, it has been shown that inhibition of SOD selectively induced apoptosis of leukemia and ovarian cancer cells [10].

Under hypoxic conditions, SOD3 is overexpressed and has been reported to significantly induce the expression of HIF-1α in tumors through unknown mechanisms however, steady state levels of O2 ●– and the stabilization of HIF-1α have been proposed to play a role in this mechanism [107, 115]. Therefore, inhibition of NAD(P)H oxidase and the consequent reduction of O2 ●– levels may destabilize HIF-1α, and subsequently increase apoptosis by lowering SOD3 levels. Thus, we conclude that lowering oxidative stress, possibly through the inhibition of NAD(P)H oxidase-generated O2 ●–, induces apoptosis in ovarian cancer cells and may serve as a potential target for cancer therapy. This effect was attributed to the modulation of key enzymes that are central to controlling the cellular redox balance.


*Article* **Urgent Need for Adolescent Physical Activity Policies and Promotion: Lessons from "Jeeluna"**

**Omar J. Baqal 1, Hassan Saleheen 2 and Fadia S. AlBuhairan 1,3,\***

Received: 17 May 2020; Accepted: 18 June 2020; Published: 21 June 2020

**Abstract:** Physical inactivity is a growing concern in Kingdom of Saudi Arabia (KSA) and globally. Data on physical activity (PA) trends, barriers, and facilitators among adolescents in KSA are scarce. This study aims to identify PA trends amongst adolescents in KSA and associated health and lifestyle behaviors. Data from "Jeeluna", a national study in KSA involving around 12,500 adolescents, were utilized. School students were invited to participate, and a multistage sampling procedure was used. Data collection included a self-administered questionnaire, anthropometric measurements, and blood sampling. Adolescents who performed PA for at least one day per week for >30 min each day were considered to "engage in PA". Mean age of the participants was 15.8 ± 0.8 years, and 51.3% were male. Forty-four percent did not engage in PA regularly. Only 35% engaged in PA at school, while 40% were not offered PA at school. Significantly more 10–14-year old than 15–19-year-old adolescents and more males than females engaged in PA (<0.01). Mental health was better in adolescents who engaged in PA (<0.01). Adolescents who engaged in PA were more likely to eat healthy food and less likely to live a sedentary lifestyle (<0.01). It is imperative that socio-cultural and demographic factors be taken into consideration during program and policy development. This study highlights the urgent need for promoting PA among adolescents in KSA and addressing perceived barriers, while offering a treasure of information to policy and decision makers.

**Keywords:** adolescent; adolescent health; physical activity; exercise; health surveillance; Kingdom of Saudi Arabia

#### **1. Introduction**

Physical activity (PA) when performed regularly, promotes well-being and helps in prevention of various health problems. In children and adolescents, PA plays a particularly critical role in growth and development, while promoting their transition into healthier adults, as lifestyle habits and PA patterns are largely established during childhood and adolescence [1]. It can help children and adolescents "see better, feel better and function better" [2]. Essentially, PA achieves this by helping them build strong bones, maintain healthy weight, improve cardiorespiratory fitness, alleviate symptoms of depression and anxiety, and also reduce the risk of developing several illnesses, such as cancer, type 2 diabetes, heart disease and obesity [2]. Studies have shown that physically active students have better grades, school attendance, cognitive performance and classroom behaviors [3,4]. It is recommended that children and adolescents between the ages of 6 and 17 years have at least 60 min of PA each day [5,6].

Despite widely recognized benefits and establishment of guidelines for PA, adolescents' PA behaviors have been far from encouraging. Globally, a significant increase in physical inactivity has been observed [7], which has led to increasing incidence of several health problems, imposing a

considerable burden upon healthcare systems of many countries. In the United States (US), it was found that only 21.6% of children and adolescents aged between 6 and 19 years attained 60 or more minutes of moderate-to-vigorous PA on at least 5 days per week [8]. In England, only 21% and 16% of boys and girls, respectively were found to meet minimum PA recommendations [9]. Even though the magnitude of the health issues associated with physical inactivity is well-known, relatively few countries conduct physical inactivity surveillance and monitoring [10].

In the Kingdom of Saudi Arabia (KSA), a consequence of rapid socio-economic growth has been striking lifestyle changes. This has had adverse effects on population health, with an increase in physical inactivity and obesity being particularly observed [11]. Prevalence of physical inactivity in the Saudi population has been found to range between 46% and an astonishing 99% in certain segments of the population [11]. A study involving Saudi school students noted high inactivity levels, with roughly only 44% of males and 20% of females being sufficiently active [12]. Consistent with global PA trends [13], males have been reported to participate more frequently in high-intensity PA than females [10].

In parallel with increasing physical inactivity, KSA has also experienced an increasing prevalence of obesity and activities that promote sedentary lifestyle, with a study noting a negative relationship between PA and obesity [14]. The same study noted a significant inverse relationship between physical activity and computer-usage (a sedentary activity), indicating that the more active the individual, the less time spent on computer-usage, with a higher body mass index (BMI) observed amongst those who reported greater computer-usage time [14]. Geographical factors have been shown to influence PA habits, with a study reporting that youths living in rural desert areas were less physically active than those living in urban or rural farm environments [15].

With the dramatic lifestyle transformation, a change in dietary habits and food consumption patterns has also been noted. Calorie-rich foods such as fast food, soft drinks, and processed snacks have become extremely affordable and accessible to children and adolescents [16]. Such food consumption patterns potentially synergize the negative effect of physical inactivity and sedentary lifestyles on population health, in turn contributing to the growing prevalence of obesity, heart disease and other non-communicable diseases. KSA's hot sun-drenched climate limits physical activity as people prefer staying indoors to avoid exposure to sunlight and heat, though there have been increasing opportunities for indoor places and activities. The widespread vitamin-D deficiency among Saudi children and adolescents has been shown to be influenced by PA and sun exposure [17].

Data on PA trends, determinants, barriers and facilitators among adolescents in Saudi Arabia have been scarce. "Jeeluna" (Arabic for "Our Generation"), a national school-based cross-sectional study involving around 12,500 adolescents in all 13 regions of KSA, found that only 13.7% of adolescents aged 10–19 years engaged in at least 30 min of PA daily [18]. To the best of our knowledge, no other studies on the same have been published exclusively on the adolescent age group (10–19 years), with most published studies focusing solely on older adolescents. This is of limited benefit when attempting to extrapolate research findings to the development of policies, programs and services promoting PA focused particularly on the adolescent age group.

The aim of this study is to identify the sociodemographic characteristics of adolescents who participate in PA in KSA, as well as their associated health and lifestyle behaviors by gender. Such information will support program and policy development that address adolescents' local needs in an evidence-based manner.

#### **2. Materials and Methods**

### *2.1. Study Design and Participants*

For this current analysis, we utilized data from the Jeeluna study database. Jeeluna was a cross-sectional, school-based, nationally representative study conducted in Saudi Arabia. Participants included intermediate and secondary school students, aged 10–19 years from all 13 regions of the country.

#### *2.2. Procedures*

A stratified, cluster random sampling procedure was used. The detailed sampling methodology has been previously published [18]. Any male/female, intermediate/secondary, public/private school in a Saudi Arabian city/town that functions during the day was eligible to participate in the study. Exclusion criteria included evening schools and schools that served students with special needs. Data collection involved: (1) administration of self-administered questionnaire; (2) anthropometric measurements; and (3) blood sampling for laboratory investigations. Data collection teams operating in all regions received standardized training.

The study received approval from the Institutional Review Board at the King Abdullah International Medical Research Center (KAIMRC) (RC08-092), as well as the Ministry of Education (MOE). It was necessary to seek permission from participating schools' principals, active written parental consent and student assent; participants were given the option to opt out of blood sampling.

For the purpose of this secondary analysis, the focus was on the PA section. It was assessed by asking students how many days in the past week they had engaged in exercise for at least 30 min each day. The cutoff of 30 min was used instead of the recommended 60 min, as PA trends have shown that most children and adolescents do not meet the recommended minimum, thus supporting the use of a lower cutoff in the analysis.

#### *2.3. Measurements*

The questionnaire was guided by the Youth Risk Behavior Survey [19] and the Global School-based Student Health Survey [20]. The global definition of health was used, so multiple domains were included and addressed in the questionnaire, including: (1) family; (2) education/schooling; (3) nutrition/dietary behaviors; (4) physical activity; (5) safety; (6) sleep; (7) violence and bullying; (8) tobacco and substance use (including alcohol use); (9) health; (10) health services; and (11) health knowledge. Students were given assurance of the anonymity and confidentiality of their responses.

Adolescents who engaged in PA for 1 or more days in a week were considered to "engage in PA". The section also included questions on sedentary activities (TV, internet, video games and cell phone use). Responses indicating time spent on each activity to be more than 2 h daily were considered to be part of the "sedentary lifestyle" category. With regard to main meals (breakfast, lunch and dinner), a value of "3" meals a day was considered healthy. Everything else, whether lower (none, 1 or 2 meals a day) or higher (4 or >4 meals a day), was put in the "unhealthy" category. We considered guidelines from the American Academy of Pediatrics (AAP) that refer to 3 meals a day as the target for healthy nutrition [21]. The 5 response choices pertaining to absence from school were grouped into 3 categories: "Not absent", "Rarely absent", and the third category including "sometimes", "often" and "always."

The "Mental health" variable was created based on responses to the questionnaire items asking about the frequency of symptoms reflecting depression or anxiety over the past 12 months. "Never", "rarely" and "sometimes" were considered as "No", and "most of the times" and "always" were considered as "Yes." The anthropometric measurement from the study database included in this analysis was BMI, which was based on measured weights and heights. BMI was classified as "Underweight", "Normal", "Overweight" and "Obese", based on Center for Disease Control and Prevention BMI charts for gender and age [22,23].

#### *2.4. Data Analysis*

The first step in the analysis was the descriptive analysis. Participants were described in terms of their selected socio-demographic status. Means along with standard deviations and percentages were calculated for continuous and categorical variables, respectively. The relationship between engaging in PA and school performance, health status, and health risk behaviors was calculated using chi-square test. A significance level of less than 0.05 was used for all statistical tests. All data were analyzed using SPSS version 25.0.3 (IBM Corp, Armonk, NY, USA).

#### **3. Results**

Participant characteristics are listed in Table 1. Mean age of the participants was 15.8 ± 1.8 years, and 51.3% were male. Most of the participants (97.9%) lived in urban areas. Little over half (53.1%) of the participants fell within the "normal" BMI range; similarly, just over half reported engaging in PA (53.4%). Only about one-third (35.4%) engaged in PA at school.

**Table 1.** Characteristics of the participants (*n* = 12,463).

¥ Percentages may not add up to 100 due to missing data.

Nationally, 92.7% of males and 7.3% of females were offered PA in schools. Out of the 13 regions, Jizan had the highest mean number of PA days per week in total (2.4 ± 2.8) as well as among males (3.3 ± 2.8). Jizan also boasts the highest proportion of total (44.7%) and male students (99.6%) engaging in PA in school. Interestingly, a stark contrast is observed in PA trends among females in Jizan, which has the lowest mean number of PA days per week in females (0.8 ± 1.7) among all regions, as well as the lowest proportion of females engaging in PA in school (0.4%). Female PA trends were dramatically better in Aljouf, which had the highest proportion of females engaging in PA in school (53.2%), and second highest mean number of PA days (1.8 ± 2.4). Detailed region-wise PA trends are displayed in Table 2.

**Table 2.** Physical activity relative to region.

Figure 1 reflects a decline in PA relative to age, with mean PA days per week of 2.7 at 12 years among males dropping to 2.1 by age 18, before rising to 2.4 by 19 years of age. In females, PA steadily declined between 12 and 19 years of age from 1.6 to 1. Significant differences in age, gender, and areas of residence, were found in terms of engagement in PA, with younger adolescents (59.6% vs. 53.5%, *p* < 0.01), males (68.3% vs. 48.7%, *p* < 0.01), and adolescents living in urban areas (55.1% vs. 47.1%, *p* < 0.01) being more likely to engage in PA. PA habits were not significantly different between Saudi and non-Saudi adolescents, as well as between the four BMI groups, with proportions of adolescents engaging in PA ranging between 54% and 57% across the BMI groups (Table 3).

**Figure 1.** Mean no. of days/week spent on >30 min of physical activity relative to age.

Table 4 represents the relationship between engaging in PA and school performance, health status, and health risk behaviors. Adolescents who engaged in PA were more likely to eat healthy food (99.1% vs. 98.3%, *p* < 0.01), less likely to live a sedentary lifestyle (63.9% vs. 67.3%, *p* < 0.01), and less likely to be absent from school (26.6% vs. 20.3%, *p* < 0.01). With regards to mental health, symptoms reflective of depression (12.2% vs. 17%, *p* < 0.01) and anxiety (5.9% vs. 7.8%, *p* < 0.01) were found to be less prevalent among adolescents who engaged in PA. Prevalence of chronic diseases as well as tobacco/substance use was not significantly different between the two groups. No significant difference was found in number of students with "excellent" academic performance among those who engage in PA and those who do not.

#### *Int. J. Environ. Res. Public Health* **2020**, *17*, 4464

#### **4. Discussion**

Research activity on PA and lifestyle habits has not matched the rapid pace at which lifestyle changes have been occurring in the KSA. This study, based on the Jeeluna national school-based study, sheds light on the status quo of PA among the adolescents of KSA and related health and lifestyle habits. Over 40% of adolescents in our study did not engage in PA at all. The remaining adolescents were part of a wide-ranging category that included those who engaged in PA once a week as well as those who engaged in PA daily. Twenty percent of males and a worrying 59% of females did not engage in PA regularly. Locally reported studies that utilized objective PA measurement techniques showed that 60% of Saudi children and 71% of youths did not engage in PA of sufficient frequency and duration [24,25].

To put local estimates including ours in perspective, it is suitable to compare them with PA estimates from other countries. A systematic assessment of literature on PA in Arab countries revealed that physical inactivity was alarmingly high in children and adolescents, reaching about 80% in all national surveys except Tunisia [26]. A Finnish study reported that 59% of boys and 50% of girls aged 15–16 years reported engaging in 60 min or more of PA per day; these estimates dropped to 23% (boys) and 10% (girls) when moderate-to-high physical activity was considered [27]. In the US, the Youth Risk Behavior Surveillance revealed that only 18.4% of adolescents met the PA guidelines [28]. The Global School-based Student Health Survey (GSHS), which included over 72,000 young people across 34 countries, showed that only 24% of boys and 15% of girls engaged in sufficient PA to meet recommendations [29]. Recently, WHO published a pooled analysis of survey data reported by 1.6 million 11 to 17-year-old adolescents across 146 countries. It found that more than 80% of school-going adolescents globally did not meet current daily PA recommendations, including 85% of girls and 78% of boys [30].

These worrying estimates of inactivity are of a great concern as inactivity has been associated with increased risk of development of cardiovascular and metabolic health conditions [2]. Modern life has paralleled technological advances, reflected in increased screen time for everyone, whether for work or leisure. This lifestyle has aimed to minimize efforts and systematically reduce energy expenditure and, in the process, to discourage physical exertion. We found that 67% of adolescents who did not exercise pursued a sedentary lifestyle. Spending time on the previously mentioned sedentary activities soaks up valuable time that could otherwise be utilized in health-promoting activities such as regular exercise. Amusingly, a lack of time has been regularly reported by individuals for their lack of PA [31,32]. Other factors that contribute to the reported adolescent inactivity rates in KSA may include lack of PA programs in schools, hot weather conditions, over-dependence on cars rather than walking even for short distances, the surrounding built environment which is not pedestrian friendly, poor peer and family support and socio-cultural barriers, which particularly impact females.

We found that males were significantly more likely to engage in PA than females. This finding is consistent with findings of several other studies [16,33,34]. This could be attributed to cultural beliefs and lifestyle patterns in KSA that possibly discourage participation of females in recreational activities outside the house. It is perhaps due to these socio-cultural differences that experts have suggested a specific gender-based consideration when making PA promotion recommendations [35]. Although males have been generally considered to have better opportunities for recreational activities including exercise than females, rapid changes have fortunately been witnessed in the past 1–2 years with more sports opportunities for females being made available in the country. The opening of female-only gyms, sports clubs, and female national sports teams have encouraged more women to engage in regular exercise. Interestingly, our study found that females who exercise were significantly more likely to eat heathy food and less likely to live a sedentary lifestyle than females who did not exercise, while there was no such significant difference between the two male groups regarding healthy eating and sedentary lifestyle. This could reflect active consciousness and awareness regarding healthy eating and lifestyle habits among females who exercise regularly. On the other hand, males seem to manage

to get sufficient PA, possibly through school and recreational activities while still personally not living an active healthy lifestyle.

Our study found a stark contrast between PA offered to males and females in schools. For example, in Jizan, 99.6% of male adolescents reported being offered PA at school, while only a shocking 0.4% of females reported the same. A local study showed that males from public schools were more active than males at private schools, whereas the opposite was true for females; they were more active in private schools [12]. While PA programs in female public schools are nearly nonexistent, private schools provide students with opportunities for regular exercise, encouraging an active and healthier lifestyle. Our findings are in agreement with this observation as most of the schools in Jizan belong to the public education system. We also reported Jizan to have the highest mean number of PA days per week among males in the whole country, while the lowest among females. Jizan is considered to be relatively more conservative when compared with the bigger cities of Jeddah and Riyadh, and thus, the cultural and lifestyle barriers to female participation in PA mentioned earlier may be augmented in this region.

We also found that adolescents aged 10–14 years were more likely to engage in PA than older adolescents aged 15–19 years. PA decline in adolescence has been previously observed [36], a trend that seems to continue into adulthood [37,38]. Increasing academic workload in secondary school could contribute to this decline, and factors such as more time spent on sedentary activities [39] as well as taking up part-time jobs [40] could also be related. This highlights the need for qualitative studies to clearly understand the reasons for this decline and to promote PA and other healthy habits in adolescence, a stage of building habits, many of which last a lifetime.

There was no significant difference in PA habits between Saudi and non-Saudi adolescents, as well as between different BMI groups. These interesting findings counter expectations, as it would generally be convenient to believe that expats from more open societies with lesser socio-cultural barriers would be living a more active lifestyle. This highlights the impact of lifestyle changes an individual adopts when living in a foreign country.

Among all of the benefits of PA and its positive effects on general health, its impact on mental health is well recognized. Exercise is known to boost self-esteem, body image and overall mood, in line with our findings of adolescents who engage in PA feeling sad or hopeless significantly less frequently than those who do not engage in PA [41]. Exercise is widely recommended by health authorities for the prevention and treatment of various non-communicable diseases, although the above mentioned benefits may depend on type, timing, and intensity of PA. Physical activity has been well-studied in the area of depression, with a study reporting 20–33% lower odds of depression in the active groups in prospective cohort studies [42]. For tasks involving more complex executive functioning, exercise was found to be associated with enhanced cognitive functioning in a meta-analysis of randomized controlled trials looking into exercise training studies in adults aged 55–80 [43,44].

We found that students who engaged in PA were significantly more likely to not be absent from school. Based on 2005–2008 NHANES (National Health and Nutrition Examination Survey) data, it was found that excessive TV watching and inactivity as well as high activity levels (>7 times per week) were independently associated with severe school absenteeism [45]. As discussed previously, excessive screen time could be taking away valuable time from adolescents that they could have spent being more physically active. Moreover, excessive TV watching can have various negative effects on a child's cognitive and socio-emotional development. Having discussed the benefits of PA on mental health, low PA levels could hamper an adolescent's participation in school, such that school is something they do not look forward to due to negative self-esteem, body image, feelings of sadness and worry, or lack of motivation.

Consequently, it is indeed worrying that despite the myriad of known health benefits, PA trends among our adolescents remain poor. PA, even in small amounts can considerably enhance physical and psychological well-being. School-based PA programs can address the enormous discrepancy between female and male PA habits in KSA by improving availability and accessibility to PA opportunities. Health care professionals, starting from the primary health care system and school health system,

must convey the benefits of regular physical activity to individuals and their families and do everything in their capacity to facilitate their participation in PA. The American Heart Association emphasizes that "the advice from healthcare professionals significantly influences adoption of healthy lifestyle behaviors, including regular PA, and can increase satisfaction with medical care" [46]. Several medical institutions, particularly in the US have begun assessing PA as a vital sign tool (indicator of general physical condition) to identity individuals who could benefit from prompt counseling or appropriate referral. Parents and guardians play a critical role in ensuring adolescents at least meet the minimum recommended amount of PA as per latest guidelines. The remarkable technological literacy of this young generation can be positively utilized by promoting active e-sports video games (e.g., Wii Sports) and health and fitness tracking applications. Above all, national health authorities, particularly the Ministry of Health, Ministry of Education, and Sports Authority must strategize an efficient multi-level action plan by taking into consideration existing data on local PA trends and lifestyle habits among adolescents, including results of this landmark study. This will also significantly contribute towards lowering the currently estimated total costs attributable to physical inactivity in KSA.

The Jeeluna study included over 12,000 adolescents, making it the largest study on adolescent health in the region to date. Additionally, the study was conducted in all 13 regions of KSA; the national representativeness of the study population enhances its generalizability. However, the study may be viewed in light of a few limitations. The study questionnaire was self-administered and may be associated with recall bias. Physical activity was not measured objectively, nor was the type of PA reported taken into consideration. In search of an explanation for the distortion of the graph line at 11 years of age, we found that the study population aged 11 years was small in number. The questionnaire did not take into consideration food portions when asking about frequency of meals. Nonetheless, the questionnaire was put through several rounds of expert review and was pilot tested for clarity and comprehension amongst the target respondent group. The study thus sets a benchmark for future adolescent health research in the country and the wider region.

#### **5. Conclusions**

The Jeeluna study highlights the urgent need for promotion of PA among adolescents in KSA and addressing perceived barriers. It is imperative that socio-cultural and demographic factors be taken into consideration during program and policy development. Schools play a critical role in improving PA habits among adolescents and remain an important focus of action, particularly for female PA promotion. Lack of PA, unhealthy food and sedentary activities are not isolated, independent health risk factors and are often found clustered among adolescents, synergistically increasing risk of disease and poor health several-fold. In order to be effective, these issues must be addressed in a cross-sectoral approach, involving multiple ministries and other stakeholders.

The study sheds light on the urgent and important issue of physical inactivity, which should be of utmost national and international interest. Our study offers valuable information to policymakers, educators and health professionals involved in the progression of adolescent health to understand young people's health in their social context. Further studies are required to be able to assess trends in PA and to evaluate impact of more recently implemented programs in the country and hence support strategies for further promotion of PA and the reduction of sedentary behavior among adolescents.

**Author Contributions:** Conceptualization, O.J.B. and F.S.A.; Data curation, F.S.A.; Formal analysis, H.S.; Funding acquisition, F.S.A.; Investigation, F.S.A.; Methodology, F.S.A.; Project administration, F.S.A.; Resources, F.S.A.; Software, H.S.; Supervision, F.S.A.; Validation, H.S.; Visualization, O.J.B., F.S.A. and H.S.; Writing—original draft, O.J.B.; Writing—review and editing, O.J.B., F.S.A. and H.S. All authors have read and agree to the published version of the manuscript.

**Funding:** JEELUNA study was supported and funded by King Abdullah International Medical Research Center (Protocol RC08-092).

**Conflicts of Interest:** The authors declare no conflict of interest.


*3.2. Material Flows Analysis and Energy Flows Analysis Results*

Material flows analysis model and energy flows analysis model could be achieved by the modeling method and sample data, which was mentioned in Sections 2.2.1 and 2.2.2. The analysis results are shown as follow.

## 3.2.1. Material Flows Analysis Results

Material flows analysis is based on the material balance between raw materials and output products. Since the amount of the gas mud, which is produced by the circulation cooling, is seldom, this part could be ignored. Then, the analytical results are shown in Figure 4.

**Figure 4.** Material flows analysis results in blast furnace iron making process (BFIMP).

(i) The material flows (including input items and output items) are all listed out through the material balance in BFIMP.

(ii) The proportions of material flow input items and output items are all clearly indicated. For example, the amount of sinter (*Px*,1), coke (*Px*,4) and oxygen-enriched air (*Pa*) accounted for about 83% in all material flow input items. Meanwhile, the purification gas (*Ppg*) and hot metal (*Phot*) accounted for about 93% in all material flow output items. Therefore, these items should be given more attention.

3.2.2. Energy Flows Analysis Results

(1) Energy flows analysis of the BS:

The energy flows analysis results of the BS are shown in Figure 5.

**Figure 5.** Energy flows analysis results in the blast system (BS).

(i) The energy flow input items and output items are all listed out through thermal equilibrium in BS.

(ii) The proportions of energy flow input items and output items are all clearly indicated in BS. For example, chemical heat of gas combustion (*Qs*,1) is the main input item (accounted for about 87%) among all energy flow input items in BS. The 75% amount of heat quantity has carried out by hot air carrying heat (*Qr*,1) in all energy flow output items.

(2) Energy flows analysis of the BF body:

The energy flows analysis results of the BF body are shown in Figure 6.

**Figure 6.** Energy flows analysis results in the blast furnace (BF) body.

(i) The energy flow input items and output items are all listed out through thermal equilibrium in the BF body.

(ii) The proportions of energy flow input items and output items are all clearly indicated in the BF body. For example, the amount of hot air physical heat (*Qr*,1) and carbon oxidation heat (*Qg*,1) accounted for 93% in all energy flow input items. The oxide decomposition heat (*Qh*,1) and hot metal carrying heat (*Qh*,6) accounted for 81% in all energy flow output items.

#### *3.3. All-Factors Analysis on Energy Consumption in BFIMP*

#### 3.3.1. PCA

As shown in Figure 6, the carbon oxidation heat (*Qg*,1), which accounted for 77.51% of the total heat consumption, is the main energy source in the BF body. Coke and pulverized coal injection are the main carriers of carbon oxidation heat [33–35]. Therefore, these two parameters can reflect the energy consumption for BFIMP.

Usually, the percentage of coke in total material consumption is called CR, the percentage of pulverized coal injection in total material consumption is called PCIR. It has been proved that that the PCIR improvement and CR reduction are the most effective energy saving measures in BFIMP [36]. Therefore, the influence factors analysis on PCIR and CR will be carried out in this paper. According to the material flows analysis results (as shown in Figure 4) and energy flows analysis results (as shown in Figure 5; Figure 6), the influence factors on CR and PCIR can be achieved. In addition, operation parameters have an important impact on CR and PCIR, too. Then, three kinds of parameters are shown in Table 1.

**Table 1.** Influence factors analysis on coke ratio (CR) and pulverized coal injection ratio (PCIR) in BFIMP by partial correlation analysis (PCA).

Noted: M40, resistance to crushing of coke; M10, abrasion strength of coke.

As shown in Table 1, the significant influence factors on the CR mainly included: Sinter size, ore grade, sinter alkalinity, sinter tumbler index, slag ratio, PCIR and blast temperature, due to their lower *p* values (≤0.05), whereas the PCIR is the best influence factors among them. The other influence factors were weakly correlated with CR due to their higher *p* values (>0.05). Moreover, the significant influence factors on the PCIR mainly included: Sinter grade, ore grade, sinter alkalinity, M10, blast volume, blast temperature, oxygen enrichment ratio and top temperature, due to their lower *p* values (≤0.05).

#### 3.3.2. MLR Models on CR and PCIR

The CR and the PCIR prediction models could be established through MLR models, based on the high correlation influence factors (as shown in Table 1). On the one hand, these prediction models have higher precision. On the other hand, this method could reduce the prediction models complexity due to a reduction in the number of variables.

Then, the fitting degrees of the MLR models were 95% and 94% respectively. In addition, these models were validated by actual production data, too. The fitting coefficients are shown in Table 2. Standardized coefficients (as shown in Table 2), which were calculated through the normalization method, eliminated the influence of dimensional differences among various parameters. Therefore, standardized coefficients could qualitatively reflect the influence intensity of each parameter on CR and PCIR. As shown in Table 2, the PCIR had the highest correlation with the CR among the main factors. Meanwhile, sinter grade had the highest correlation with the PCIR.

**Table 2.** Multivariate linear model (MLR) modelson CR and PCIR.

#### **4. Discussion**

Furthermore, a quantitative analysis was adopted to evaluate the influence intensity of the factors (independent variables) on the dependent variables (CR or PCIR). Generally, every independent variable was divided into 100 parts between minimum and maximum, which was achieved using historical production data (as shown in Table 3). Then, the variation of the dependent variable, which was caused by the change of independent variable 1%, could be calculated through MLR models. Quantitative influence intensity of significant factors on CR and PCIR are shown in Figures 7 and 8.

**Table 3.** The range of the influence factors (independent variable).

**Figure 7.** The influence intensity of significant factors on CR.

**Figure 8.** The influence intensity of significant factors on PCIR.

Slag ratio, sinter alkalinity and blast temperature had a positive influence on CR (as shown in Figure 7), the other factors had a negative influence. Meanwhile, the influence intensity of PCIR was the greatest among them on CR. CR would reduce by 0.507 kg/t when PCIR increased by 1% (0.84 kg/t), whereassinter size was the weakest.

As shown in Figure 8, M10 had a negative influence on PCIR among the main factors. The other factors had a positive influence. The influence intensity of sinter alkalinity was the greatest among them on PCIR. PCIR would increase by 0.483 kg/t when sinter alkalinity was promoted to 1% (0.005%), whereas M10 was the weakest.

As shown previously, some factors not only affected the CR, but also affected the PCIR, such as ore grade, sinter alkalinity and blast temperature. For example, CR would decrease and PCIR would increase with ore grade increasing. Furthermore, CR would continue to fall due to the improvement of PCIR (as shown in Figures 7 and 8). Therefore, ore grade had a comprehensive effect on CR. Meanwhile, it was the same for sinter alkalinity and blast temperature. In order to further analyze this problem, the influence factors, which affected PCIR, were converted to CR. Consequently, the comprehensive influence intensity on CR could be achieved (as shown in Figure 9).

**Figure 9.** The comprehensive influence intensity of significant factors on CR.

In general, the slag ratio and M10 had a positive influence on CR among influence factors, whereas the rest of the factors had a negative influence (as shown in Figure 9). Meanwhile, the influence intensity of the ore grade was the strongest; the sinter size was the weakest among the material parameters. CR would reduce by 0.471 kg/t, when the ore grade increased by 1% (0.48 kg/t). CR would only reduce by 0.054 kg/t, when the sinter size increased by 1% (0.053 mm). It is worth mentioning that ore grade and sinter alkalinity had a positive influence not only on PCIR, but also on CR. Although CR would increase with the improvement of ore grade and sinter alkalinity, CR would reduce with the improvement of PCIR, which was also caused by increasement of ore grade and sinter alkalinity. Therefore, ore grade and sinter alkalinity had a negative influence on CR finally after conversion calculation.

M10, which belongs to the unique energy flows parameter, had an impact on CR. CR would increase by 0.094kg/t when the M10 increased by 1% (0.021%).

Among the operation parameters, the influence intensity of blast volume was the strongest. CR would reduce by 0.289 kg/t when blast volume increased by 1% (7.09 m3/min), whereas blast temperature was the weakest. As before, blast temperature had also a positive influence on the CR and PCIR (as show in Figures 7 and 8). Eventually, blast temperature had a negative influence on CR after conversion calculation (as shown in Figure 9). CR would reduce by 0.077 kg/t when blast temperature increased by 1% (1.64◦C).

In summary, there were many influence factors, which determined the amount of PCIR and CR. Therefore, it is a very important energy saving direction to determine how to improve these influence factors in BFIMP. Then, three kinds of parameters (material flows, energy flows and operation parameters) will be further discussed.

(1) Material flows improvement:

The improvement of sinter size, ore grade, sinter grade, sinter tumbler index and sinter alkalinity could improve the permeability in the BF body. Moreover, the production status could be more stable. Therefore, the improvement of these factors provides favorable conditions for increasing the PCIR. Meanwhile, the improvement of ore grade and sinter grade is conducive to a reduction of the slag ratio. Moreover, the amount of PCIR and CR will also drop.

(2) Energy flows improvement:

M10 is a physical performance index, which can reflect the coke abrasion strength. The decrease of M10 is beneficial to charge column permeability for gas in the BF body, too. Therefore, if the amount of pulverized coal injection is further increased, the quantity of coke could be dropped.

(3) Operation parameters improvement:

The increase of blast volume, blast temperature and oxygen enrichment ratio can effectively maintain a high temperature in the combustion zone. Moreover, they are also conducive to accelerating the pulverized coal decomposition and combustion. In addition, the improvement of blast volume and blast temperature is also favorable to blow the hearth center of the BF body (especially for pyknic-type BF). Furthermore, the increase of blast temperature, which can improve the heat input of the BF body, can reduce the demand for coke or pulverized coal. Meanwhile, the combustion efficiency of coke and pulverized coal are improved due to the increase of the oxygen enrichment ratio. Then, the amount of flue gas is further reduced. Therefore, the improvements of blast volume, blast temperature and oxygen enrichment ratio are very effective measures of energy saving in BFIMP. Additionally, top temperature, which directly can reflect gas distribution and blast furnace status, is determined by heat exchange between blast furnace gas and furnace charge. CR will drop with top temperature increasing. Therefore, top temperature, which is controlled in higher areas within allowable range, is also an effective energy saving measure.

The analysis indicates the following findings.


*2.1.1 Spatiotemporal of determination of the urban form*

The urban form is not indifferent to space–time, but not taken as such, because they are transformable elements, imprinting on the urban existence a succession of states. The spatiotemporal determination of the urban form lies between innovation and tradition. The urban form does not have to be shaped at any given moment by acquiring space, time, or a conventional model.

**7**

*City Phenomenon between Urban Structure and Composition*

The city represents a multifaceted structure of social organization, which involves a number of social institutions and a typical configuration of social relations. A sustainable city is organized so as to enable all its citizens to meet their own needs and to enhance their well-being without damaging the natural world or endangering the living conditions of other people, now or in the future [3, 7]. This makes the users of the city, the social relations they develop in cities, the ways in which they live, the problems they face, and the urban space in general the object of research of modern urban studies. A human being in urban composition means to get yourself on a doctrinal position. The composition in urban scale is based on both the structure and the doctrine (ideology). In urban composition, esthetics remains just one aspect, where the urban form is read as a static instance. It is a concrete land, inscribed in history, having a memory and therefore not completely subordinating to the needs or the will of a class, preserving morphological landmarks that illustrate this resistance. At the same time, the memory of the place, a notion determined historically and socially, plays an important role in the permanence of the significance of some urban spaces; it illustrates: "what one epoch finds worthy of attention in another." It is considered an artifact because it is the physical result of the aspirations of the urban society, created by its reference elements, the public buildings. Architecture always expresses and illustrates the social and cultural potential of an era. A city includes rights and freedoms for all its inhabitants, promotes social and political participation, informs its citizens, and makes democratic decisions. Economic inclusion refers to public policies to support the poor and to provide equal opportunities in business and equal access to the labor market. Cultural inclusion: an inclusive city promotes social integration and celebrates diversity. It respects the cultural rights of individuals, recognizes human capital in all segments of society and strives to increase it by promoting creative artistic expression and preservation of traditions. The concept of "the city for all" and "the right to the city" refers to the access of social and economic benefits by all the inhabitants, promoting social equality and access to the benefits of urban living, for each inhabitant. A city must dig even on the social, political, economic, and cultural levels, if no efforts are made in this respect, and then continue promoting the exclusive development and sharing of benefits, marginalization, and discrimination. The city administration must be well aware of the sociocultural realities that make up the social life of the respective city; they must strive to build and promote inclusive strategies and policies and then integrate these strategies into the daily lives of the population. The city has been and remains a land of negotiation between various social groups; harmonious cohabitation in cities is a difficult process, which is often punctuated by various urban social movements. In general, these movements challenge the social order and the existing public policies, fighting for visibility on the social scene and for a fair distribution of resources. Cities in their evolution have undergone a permanent territorial extension and intense remodeling. The forms of evolution and urban concentration are different from one area to another and from one region to another. They differ in both genesis and size. Depending on these two elements, several forms of urban concentration can be distinguished. Therefore, the city does not only mean buildings, roads, parks, fences, abandoned corners, water pipes, and cable networks, but especially interactions between citizens, contacts, social relations, and communication situations, direct and indirect [8]. All these make up the complexity of urban social life and give life to cities. In another view of this subject, the urban habitat expresses the synthesis of the conditions of human life, of the social-economic reality existing at one point. At the global scale, the

*DOI: http://dx.doi.org/10.5772/intechopen.90443*

**2.2 City as a social-human settlement**

### **2.2 City as a social-human settlement**

*Sustainability in Urban Planning and Design*

**2.1 The city as an urban phenomenon**

• Units/less unitary

• Dense/less dense

• Intense/less intense

and sound

three sides:

systems and subsystems. The urban phenomenon can be:

reflects the evolution of the urban phenomenon, it has:

post-existing urban existence

a.The ability to express itself very differently either:

References of the urban phenomenon to the logic of form and to the dialectic of content justify its understanding as a system. These references impose relationships between the components of the urban phenomenon, so that they are realized in

The urban phenomenon as a system is defined only through the urban form, the fact that leads us to the idea of knowing and directing the urban phenomenon (of its processes and acts) through careful, corroborated analysis of the manifestations of any kind of urban form [6]. The urban form has a dialectic character, which

○ In particular: within a certain urban existence, through image, movement,

○ In abstract: imaginative—within the representation of the pre-existing or

b.Graphically: by mathematical-geometric, technical, and plastic means

c.Verbally: by the psychosociological or mathematical-statistical concept

The urban form has the capacity to move from a logical, but an abstract manifestation (through a certain language), into a form of effective actions, which results in a certain urban existence. It had an active character which can highlight

• Selectivity with histories and character: any urban form, any urban existence, is the result of historical evolution. The urban form has the capacity to evolve, selecting over time the various values within the respective urban existence.

• A possibility to create an urban strategy at the conception and decision levels,

The urban form is not indifferent to space–time, but not taken as such, because they are transformable elements, imprinting on the urban existence a succession of states. The spatiotemporal determination of the urban form lies between innovation and tradition. The urban form does not have to be shaped at any given moment by

• A capacity of reunification: of old or new contents in a totality.

which represent a reflection for a certain city existence.

*2.1.1 Spatiotemporal of determination of the urban form*

acquiring space, time, or a conventional model.

**6**

The city represents a multifaceted structure of social organization, which involves a number of social institutions and a typical configuration of social relations. A sustainable city is organized so as to enable all its citizens to meet their own needs and to enhance their well-being without damaging the natural world or endangering the living conditions of other people, now or in the future [3, 7]. This makes the users of the city, the social relations they develop in cities, the ways in which they live, the problems they face, and the urban space in general the object of research of modern urban studies. A human being in urban composition means to get yourself on a doctrinal position. The composition in urban scale is based on both the structure and the doctrine (ideology). In urban composition, esthetics remains just one aspect, where the urban form is read as a static instance. It is a concrete land, inscribed in history, having a memory and therefore not completely subordinating to the needs or the will of a class, preserving morphological landmarks that illustrate this resistance. At the same time, the memory of the place, a notion determined historically and socially, plays an important role in the permanence of the significance of some urban spaces; it illustrates: "what one epoch finds worthy of attention in another." It is considered an artifact because it is the physical result of the aspirations of the urban society, created by its reference elements, the public buildings. Architecture always expresses and illustrates the social and cultural potential of an era. A city includes rights and freedoms for all its inhabitants, promotes social and political participation, informs its citizens, and makes democratic decisions. Economic inclusion refers to public policies to support the poor and to provide equal opportunities in business and equal access to the labor market. Cultural inclusion: an inclusive city promotes social integration and celebrates diversity. It respects the cultural rights of individuals, recognizes human capital in all segments of society and strives to increase it by promoting creative artistic expression and preservation of traditions. The concept of "the city for all" and "the right to the city" refers to the access of social and economic benefits by all the inhabitants, promoting social equality and access to the benefits of urban living, for each inhabitant. A city must dig even on the social, political, economic, and cultural levels, if no efforts are made in this respect, and then continue promoting the exclusive development and sharing of benefits, marginalization, and discrimination. The city administration must be well aware of the sociocultural realities that make up the social life of the respective city; they must strive to build and promote inclusive strategies and policies and then integrate these strategies into the daily lives of the population. The city has been and remains a land of negotiation between various social groups; harmonious cohabitation in cities is a difficult process, which is often punctuated by various urban social movements. In general, these movements challenge the social order and the existing public policies, fighting for visibility on the social scene and for a fair distribution of resources. Cities in their evolution have undergone a permanent territorial extension and intense remodeling. The forms of evolution and urban concentration are different from one area to another and from one region to another. They differ in both genesis and size. Depending on these two elements, several forms of urban concentration can be distinguished. Therefore, the city does not only mean buildings, roads, parks, fences, abandoned corners, water pipes, and cable networks, but especially interactions between citizens, contacts, social relations, and communication situations, direct and indirect [8]. All these make up the complexity of urban social life and give life to cities. In another view of this subject, the urban habitat expresses the synthesis of the conditions of human life, of the social-economic reality existing at one point. At the global scale, the

population is divided into two major types of habitat: rural and urban, between which there are similarities, but also fundamental differences. The urban habitat or the city is a form of human settlement superior of the village, which is distinguished by a higher density of population and constructions, superior technical-urban equipment, mainly secondary and tertiary economic activities, a specific way of life, and with a higher demographic potential. Although these criteria are clear enough to distinguish the village from the city, they are not necessarily the same for everyone. Depending on the region and the age, the idea we make about the city changes. Each civilization has a different conception of the city. Certain ancient cities, populated mostly by cultivators, cannot be considered cities in our view. Difficulties in differentiating the village and town arise from the lack of accuracy of the vocabulary. The city is a space that is defined by a series of metric properties, by dimensions, surfaces, and densities. It is an intensely populated space, with a high degree of concentration, production, and social and cultural organization, which develops under certain conditions of space and time, thanks to the convergence of the forces of production and in permanent opposition to the village. Urban social studies analyze urban life in all its complexity. Through explanations and information provided in urban studies, we can better understand the reality and social, cultural, and economic phenomena that are happening in the urban environment around us; we can understand the causes of these phenomena; we can understand the sociocultural diversity; and we can find new opportunities to live together and creatively use urban spaces.

### **2.3 City as a form of human life in the context of a complex dynamic system**

A city is not just a place to live, but a complex and dynamic system that unites a certain community of people and is called upon to ultimately improve the quality of life of every person. Urban spaces are formed under the influence of many factors and over long periods. When designing an urban environment, the designer must take into account the compositional. The idea that heterotopia does not inevitably mean a state of urban chaos can be retained here, that distant order can, in many cases, be particularly subtle. One of the most complicated and, at the same time, very topical issues regarding the urban form is that of spatial differentiation as a way of explaining the existence in any urban situation of different spaces between them. First, the aspect of understanding spatial differentiation appears in the sense of a dialectical result in the process of constituting the urban form, namely, in the sense that the urban form is the expression for the purpose of the urban phenomenon. However, this understanding must not be inclined toward the metaphysical, that is, it must not be considered in the sense that a certain expression of the urban form is completely and definitively recognized as a final expression, beyond which nothing can appear. It continues to evolve over a period of time greater or less, in which it remains in the same form (unitary or non-unitary), until, undergoing a new transformation process, it reaches another form, constituting itself as the new existence that can be considered as a new moment of finality [9]. This is why we can say that the urban form as a finality of the urban phenomenon is in the process of continuous perfection. It is noteworthy that precisely this process creates spatial differentiation, this differentiation occurring either within the same urban space (frame, element for an urban existence) from one moment to another of its evolution, or within the city, when an urban space arrives. At a time, a purpose that is different from that of other urban space at the same time. So, within the city, we have to deal with a spatial differentiation to be analyzed either in a horizontal temporal section (without neglecting the constitution overtime of the respective urban spaces) or in a vertical temporal section (insisting on the evolutionary character of the respective urban space). Although, at least in the first situation, the

**9**

*– What is urban empathy space?*

*City Phenomenon between Urban Structure and Composition*

the urban area, and even the urban furniture itself.

**2.4 City as an urban utopian and empathy space**

differentiation can be caught only through a structural analysis of urban spaces; it cannot ensure the depth of our conclusions, especially if, at the level of detail or, on the contrary, at the level of the whole, they are necessary for defining aspects which characterize the urban form in a certain area, in a certain time. The urban form concerns the morphological characteristics of the urban framework both in general, at the scale of the entire city (extension, perimeter, street network, watercourses, etc.), and in detail, the relation of a building with the surrounding urban framework, a group of buildings, ensemble, and neighborhood structure of the urban framework [9]. The transformation of the living environment, including the design of the urban environment, is one of the most urgent problems solved by the modern designer—an active participant in creating the environment of the environment, educator, and exponent of the culture and esthetic taste of society. The urban design is oriented to interpret the form and public space with physical-estheticfunctional criteria, seeking to meet the needs of urban communities or societies, within a consideration of collective benefit in an existing or future urban area, until reaching the conclusion of an urban structure to follow. Therefore, the urban design performs physical planning at analysis levels, such as the region, the urban center,

Utopian space has a special feature. It is defined as combining both the close order and the distant order, at the concept level, between urban isotope and heterotopy. But if these are characteristics that address the material existence, therefore exclusively to what is perceived (in volumetric, color, movement, noise), the space considered as utopian has a deep subjective potential, its appreciation being closely related to the psychic. Heterotopic spaces are spaces that reveal different places, each supported by different functional, spatial, and encompassing characteristics. But also within the same urban space—the more complex it is, the more obvious this observation is—we can also find isotopic states or heterotopic states, which gives the space a homogeneity or heterogeneity. Symbols are commonly applied to formal iconographic representations. Symbolism encompasses complex conceptual codes and pictorial representations of a worldview that operates on multiple levels and scales [10]. Differentiation in the sense of heterotopy isotope, in the context of an urban situation, is not fixed. Urban symbolism is commonly associated with the enhancement of formal urban figures, objects, or pieces of the collection and landmarks [11]. The utopian space is, in general, a symbolic space, and what the architects forget, a space with imaginary availability not for themselves, but for those who cross it as ignorant of a survey methodology of analysis, but directly and perhaps impressively primitive. For example, a utopian space can be, within the city, an organized market, but extremely wide, whose limits come out of the natural perception, the image retaining the volumetric, but also a passage of the outer space. Then our psyche, as well as our imaginary, intervenes in determining a certain environment, a certain impression at that moment and in that place. As a utopian space, any urban space may appear during the night, when a number of aspects of its configuration fade, even though during the day it may be an isotopic or heterotopic space. The significance of urban space, obviously determined by its functionality and geometrical-spatial appreciation, cannot be achieved except for a small but constructive, utopian value. The monumental, like the enchanting, are features that serve the significance of the urban space; however, there are traits that constitute a spatial approach/recognition/perception, at least in part utopian.

*DOI: http://dx.doi.org/10.5772/intechopen.90443*

#### *City Phenomenon between Urban Structure and Composition DOI: http://dx.doi.org/10.5772/intechopen.90443*

*Sustainability in Urban Planning and Design*

population is divided into two major types of habitat: rural and urban, between which there are similarities, but also fundamental differences. The urban habitat or the city is a form of human settlement superior of the village, which is distinguished by a higher density of population and constructions, superior technical-urban equipment, mainly secondary and tertiary economic activities, a specific way of life, and with a higher demographic potential. Although these criteria are clear enough to distinguish the village from the city, they are not necessarily the same for everyone. Depending on the region and the age, the idea we make about the city changes. Each civilization has a different conception of the city. Certain ancient cities, populated mostly by cultivators, cannot be considered cities in our view. Difficulties in differentiating the village and town arise from the lack of accuracy of the vocabulary. The city is a space that is defined by a series of metric properties, by dimensions, surfaces, and densities. It is an intensely populated space, with a high degree of concentration, production, and social and cultural organization, which develops under certain conditions of space and time, thanks to the convergence of the forces of production and in permanent opposition to the village. Urban social studies analyze urban life in all its complexity. Through explanations and information provided in urban studies, we can better understand the reality and social, cultural, and economic phenomena that are happening in the urban environment around us; we can understand the causes of these phenomena; we can understand the sociocultural diversity; and we can find

new opportunities to live together and creatively use urban spaces.

**2.3 City as a form of human life in the context of a complex dynamic system**

A city is not just a place to live, but a complex and dynamic system that unites a certain community of people and is called upon to ultimately improve the quality of life of every person. Urban spaces are formed under the influence of many factors and over long periods. When designing an urban environment, the designer must take into account the compositional. The idea that heterotopia does not inevitably mean a state of urban chaos can be retained here, that distant order can, in many cases, be particularly subtle. One of the most complicated and, at the same time, very topical issues regarding the urban form is that of spatial differentiation as a way of explaining the existence in any urban situation of different spaces between them. First, the aspect of understanding spatial differentiation appears in the sense of a dialectical result in the process of constituting the urban form, namely, in the sense that the urban form is the expression for the purpose of the urban phenomenon. However, this understanding must not be inclined toward the metaphysical, that is, it must not be considered in the sense that a certain expression of the urban form is completely and definitively recognized as a final expression, beyond which nothing can appear. It continues to evolve over a period of time greater or less, in which it remains in the same form (unitary or non-unitary), until, undergoing a new transformation process, it reaches another form, constituting itself as the new existence that can be considered as a new moment of finality [9]. This is why we can say that the urban form as a finality of the urban phenomenon is in the process of continuous perfection. It is noteworthy that precisely this process creates spatial differentiation, this differentiation occurring either within the same urban space (frame, element for an urban existence) from one moment to another of its evolution, or within the city, when an urban space arrives. At a time, a purpose that is different from that of other urban space at the same time. So, within the city, we have to deal with a spatial differentiation to be analyzed either in a horizontal temporal section (without neglecting the constitution overtime of the respective urban spaces) or in a vertical temporal section (insisting on the evolutionary character of the respective urban space). Although, at least in the first situation, the

**8**

differentiation can be caught only through a structural analysis of urban spaces; it cannot ensure the depth of our conclusions, especially if, at the level of detail or, on the contrary, at the level of the whole, they are necessary for defining aspects which characterize the urban form in a certain area, in a certain time. The urban form concerns the morphological characteristics of the urban framework both in general, at the scale of the entire city (extension, perimeter, street network, watercourses, etc.), and in detail, the relation of a building with the surrounding urban framework, a group of buildings, ensemble, and neighborhood structure of the urban framework [9]. The transformation of the living environment, including the design of the urban environment, is one of the most urgent problems solved by the modern designer—an active participant in creating the environment of the environment, educator, and exponent of the culture and esthetic taste of society. The urban design is oriented to interpret the form and public space with physical-estheticfunctional criteria, seeking to meet the needs of urban communities or societies, within a consideration of collective benefit in an existing or future urban area, until reaching the conclusion of an urban structure to follow. Therefore, the urban design performs physical planning at analysis levels, such as the region, the urban center, the urban area, and even the urban furniture itself.


**3.2 Thermal analysis**

Differential scanning calorimetry (DSC) is a frequently used technique for gaining thermal information such as enthalpy of melting and other melting data and is used for screening of co-crystals [22]. The type of solid formed can be identified from DSC thermogram. For example, a physical mixture has two endotherms indicating the melting points of components with no intermolecular forces between them [42], and a eutectic system has a particular endotherm having latent heat, not more than the corresponding components [43], while a co-crystal has a particular endotherm having latent heat lesser, higher, or in the middle of the parent components [44].