**2. Traditional approaches in maize crop improvement**

Based on recent molecular analysis, it is now believed that the process of maize domestication commenced in the Central Balsas River Valley approximately 8700 long ago in southwestern Mexico. This domestication process occurred rapidly, originating from *Zea mays* ssp. *parviglumis* wild precursor, a subspecies of teosinte. This information is supported by studies conducted by Liu et al. [13], Piperno et al. [14], and Ranere et al. [15]. At the International Institute of Tropical Agriculture (IITA), maize underwent enhancements in various quantitative traits through classical or conventional methods. These improvements encompassed traits such as Striga resistance, nitrogen utilization efficiency, drought tolerance, resilience to stem borers, mitigation of aflatoxin accumulation, yield potential, and enhancement of nutritional quality [16, 17]. In traditional maize breeding, the approach entails the development of new plant cultivars by adhering to the principles of natural inheritance. This involves the selection of plants based on their exceptional performance in specific traits or characteristics, as discussed by Lamichhane and Thapa [18]. Conventional breeding methods have been employed for the two, self-pollinated and cross-pollinated plants for quite shortly. One example is the concept of pure line selection, which was introduced by Johannsen [19], as documented by Poehlman [20]. This method involves the creation of pure lines through the self-pollination of a single superior homozygous parental genotype. Following several years of conducting multi-locational trials, typically spanning approximately 6–7 years and involving the comparison with established check varieties, superior genotypes are officially introduced as new maize varieties. Pure-line selection is less effective due to low heritability caused by environmental effects, as genetic makeup closely resembles parental genotypes [21]. Mass selection, akin to pure-line selection, relies on highly heritable traits for plant choice [22]. Mass selection can be executed in two ways; the first is single-parental,

where one kind of gamete is controlled, and the second one is bi-parental, where a couple of gametes, female and male are controlled. The chosen individuals are then planted in the crop land and harvested when they reach maturity. After harvest, seeds are mixed and sowed for the next generation. In the next year, crop plants grown from mixed seeds are justified with a check variety for variance. Selected plants are released as new varieties after multi-location trials. Backcross breeding introduces desirable traits from one plant into another without affecting other traits by crossing with a homozygous parent [23]. In this method, donor parents possess the desired trait, and recurrent parents receive these selected genes. After five to six generations of repeated backcrossing with the recurrent parent, the backcrossed progeny should inherit approximately 98% of the recurrent parent's genome [24]. In backcross breeding, the newly formed variety typically inherits a majority of its genes from the recurrent parent, with only a few coming from the donor parent, as noted by Singh [25]. Another method is recurrent selection, a term introduced by Hull [26], primarily applied in maize breeding but later extended to other cereal crops, as discussed by Ramya et al. [27]. This process entails the continued selection of favorable traits over multiple generations, to increase their prevalence through crosses between high-performing individuals from the heterozygous recurrent parent and inbred individuals, as discussed by Bangarwa [28]. Hybridization is another method for creating hybrids with desirable traits by mating genetically distant parents within the same species (Intraspecific hybridization) or between different species (Interspecific hybridization). It involves combining characteristics from different parents to produce genetically superior offspring, whether through natural or artificial means [21].

In a remarkable long-term study conducted with conventional breeding techniques, researchers at the Illinois Agricultural Experiment Station successfully enhanced the oil concentration in maize. They started with a base of approximately 5% oil content and, throughout 100 generations, developed high oil-producing maize lines, which now boast an impressive 20% oil content [29]. However, conventional breeding methods do have their limitations. For instance, identical parents do not produce variation due to the lack of segregation of gametes in conventional breeding [30]. Additionally, this process is often time-consuming, typically spanning over a decade or more before a new cultivar is ready for release, as noted by Bharti and Chimata [31]. Moreover, conventional breeding heavily relies on the cultivars phenotypic expressions to identify superior ones. Hence, the chosen cultivars may not consistently be without errors, given that phenotypes are significantly affected by genotype-environment interactions [32]. The selection process involves choosing individuals for breeding based on their differences in desired features, which are usually measurable or observable traits [33]. It's worth noting that conventional breeding is an applied science that heavily depends on the observations, skills, and experiences of breeders for judgment, as highlighted by Allard [34].


**Nanoparticle Insulin Drug Delivery — Applications and New Aspects**

Hatice Kübra Elçioğlu and Ali Demir Sezer

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/58538


**Author details**

Ayesha Kausar1,2\*

\*Address all correspondence to<EMAIL_ADDRESS>
1 Nanosciences Division, National Center For Physics, Quaid‐i‐Azam University, Islamabad, Pakistan

2 Department of Chemistry, Quaid‐i‐Azam University, Islamabad, Pakistan


**4. Hydrology and environment variables**

The freshwater discharge of the Madeira River is characterized by an annual unimodal cycle defined by four phases: low, rising, high and falling water level. The low water level phase is when the discharge is minimal and the river beach is exposed, usually between August and November, while the high water level phase is when the discharge is high and the river floods the marginal areas, it occurs generally between February and May. Other months are consid‐ ered transition phases when the water level is rising or falling. The rising water level phase is when begins the rainy season and the river discharge starts to increase, between December and January, and the falling water level phase is when the river discharge decreases and the flood retreats, between June and July. The diary discharge median estimated for the study period was 15 thousand m3 /s, which was used to separate the low and high discharge phases. Interannual variations of the hydrological cycle were observed during the period studied, with a short and intensive high discharge phase in 2010 (<160 days and >39 thousands m3 /s) in relation to other years (>190 days and <36 thousands m3 /s) (Figure 3).

to the discharge, and the highest values occurred during the low discharge period (rconductivity= -0.74, rpH= -0.46; p<0.01, n=36). The mean turbidity is also high in relation to the other rivers, varying from 84 to more than one thousand NTU, with the highest turbidity value occurring in the beginning of the high discharge period (Pearson correlations: r= 0.63, p<0.01, n=36). The dissolved oxygen mean was relatively high, which can be associated with the aeration process caused by the movement of water in the rapids. The monthly average ranged from 5.7 to 8.8 mg/l and there was an inverse relationship with the discharge (r= -0.41, p<0.05, n=36). The high river discharge is associated with the flooding of the wetland and decomposition of large amount of organic material, which consumes oxygen of the aquatic environment (Table 1).

Diversity and Abundance of Fish Larvae Drifting in the Madeira River, Amazon Basin: Sampling Methods Comparison

http://dx.doi.org/10.5772/57404

143

**Month Conductivity Temperature Oxygen Ph Turbidity** 73 27.5 8.6 7.03 1.137 69 27.1 7.0 6.83 1.129 73 27.0 5.7 6.94 961 78 27.6 6.7 7.10 564 80 27.6 6.7 6.69 401 74 26.9 7.6 6.75 298 90 27.2 8.9 6.08 205 107 26.4 8.8 7.88 180 131 28.1 8.6 8.07 84 121 29.4 7.8 7.98 411 105 29.4 7.5 7.48 320 78 27.9 7.1 7.28 806 Mean 89.61 27.67 7.59 7.17 551.57 SD 22.68 1.14 2.20 0.87 421.58

**Table 1.** Average monthly of the physicochemical parameters obtained in the Madeira River.

During the three years, 4,148 individuals were collected by 432 samples of ichthyoplankton realized monthly in four transects, with an average of 9.5 samples by transect and method. The number of samples were similar for each combination of sampling methods and nets, however there were more samples in downriver (Jirau: 56%) than in upriver (Abunã: 44%). This difference in samples number was due to the river width, which is related to the number of sampling sites for integrating sampling method. A total of 21,665 larvae (99%) and 282 eggs (1%) were collected. The point sampling (PL) method was more efficient at collecting eggs than the integrating sampling methods. The PL collected 53% of the eggs, followed by the integrat‐ ing sampling method with juvenile net (IJ), that collected 29%, and the integrating sampling method with larvae net (IL), that caught the remains 17% of the eggs. The PL method also

**5. Ichthyoplankton abundance**

**Figure 3.** The hydrological cycle of the Madeira River Basin obtained at the Hydrological Station of Abunã, at the up‐ river of the study area (discharge- continuous line; water level- dotted line).

The Madeira River is a muddy river that receives a large amount of sediments rich in mineral salt, which comes from Andean region. Due to this, the monthly averages of the conductivity and pH are in general higher than the other rivers of the Amazon Basin, varying from 69 to 131 µS/cm and 6 and 8, respectively. The conductivity and pH values were inversely related to the discharge, and the highest values occurred during the low discharge period (rconductivity= -0.74, rpH= -0.46; p<0.01, n=36). The mean turbidity is also high in relation to the other rivers, varying from 84 to more than one thousand NTU, with the highest turbidity value occurring in the beginning of the high discharge period (Pearson correlations: r= 0.63, p<0.01, n=36). The dissolved oxygen mean was relatively high, which can be associated with the aeration process caused by the movement of water in the rapids. The monthly average ranged from 5.7 to 8.8 mg/l and there was an inverse relationship with the discharge (r= -0.41, p<0.05, n=36). The high river discharge is associated with the flooding of the wetland and decomposition of large amount of organic material, which consumes oxygen of the aquatic environment (Table 1).

**Table 1.** Average monthly of the physicochemical parameters obtained in the Madeira River.


**Meet the editor**

Dr. Volodymyr I. Lushchak graduated from the Lomonosov Moscow State University (Soviet Union) in 1982. In 1986 he defended his Ph.D. Theisis and in 2002 his D.Sc. Dissertation. He obtained his full professor title in 2004. From 1987 to 1998 he worked in Southern Seas Biology Institute of Academy of Sciences of Ukraine. In 1998 Dr. Lushchak joined Vassyl Stefanyk Precarpathian Nation-

al University in Ivano-Frankivsk, Ukraine) where he currently works as the head of the Department of Biochemistry and Biotechnology. He also worked at Universities of Canada, Brazil, United Kingdom, Finland, Poland, Sweden and Germany. Dr. Lushchak's scientific interests are related to effects of environmental conditions and molecular aspects of adaptive responses in bacteria, fungi, plants and animals. Although interested in general aspects of metabolism regulation, his interests are mainly focused on the homeostasis of reactive species of oxygen, nitrogen and carbon.

Contents

**Preface IX**

Chapter 1 **Introductory Chapter 3**

**Section 2 Physical Factors 11**

**Section 3 Chemical Factors 113**

Chapter 6 **Oxidative Stress Induced**

Volodymyr I. Lushchak

Chapter 2 **Oxidative Stress Induced Damage**

Chapter 3 **Exercise and Oxidative Stress 33**

**of the Human Retina: Overview**

Vladimir Lj. Jakovljevic, Dejan Cubrilo,

**Stress Events in Antarctic Fungi 75**  Nedelina Kostadinova, Ekaterina Krumova,

Chapter 5 **Changes in Hydrogen Peroxide Levels and Catalase**

Tayeb Wafa, Nakbi Amel, Chaieb Ikbal

and Hammami Mohamed

**Isoforms Expression are Induced With Freezing Tolerance by Abscisic Acid in Potato Microplants 99**  Martha E. Mora-Herrera, Humberto López-Delgado, Ernestina Valadez-Moctezuma and Ian M. Scott

**by the 2,4-Dichlorophenoxyacetic Herbicide 115**

Chapter 4 **Transient Cold Shock Induces Oxidative**

**of Mechanisms and Preventional Strategies 13**  Katrin Engelmann, Klio Ai Becker and Richard Funk

Vladimir Zivkovic, Dusica Djordjevic and Dragan Djuric

Tzvetanka Stefanova, Vladislava Dishliyska and Maria Angelova

**Section 1 Introduction 1**

### Contents

#### **Preface XIII**

**Section 1 Introduction 1**  Chapter 1 **Introductory Chapter 3**  Volodymyr I. Lushchak **Section 2 Physical Factors 11**  Chapter 2 **Oxidative Stress Induced Damage of the Human Retina: Overview of Mechanisms and Preventional Strategies 13**  Katrin Engelmann, Klio Ai Becker and Richard Funk Chapter 3 **Exercise and Oxidative Stress 33**  Vladimir Lj. Jakovljevic, Dejan Cubrilo, Vladimir Zivkovic, Dusica Djordjevic and Dragan Djuric Chapter 4 **Transient Cold Shock Induces Oxidative Stress Events in Antarctic Fungi 75**  Nedelina Kostadinova, Ekaterina Krumova, Tzvetanka Stefanova, Vladislava Dishliyska and Maria Angelova Chapter 5 **Changes in Hydrogen Peroxide Levels and Catalase Isoforms Expression are Induced With Freezing Tolerance by Abscisic Acid in Potato Microplants 99**  Martha E. Mora-Herrera, Humberto López-Delgado, Ernestina Valadez-Moctezuma and Ian M. Scott **Section 3 Chemical Factors 113**

Chapter 6 **Oxidative Stress Induced by the 2,4-Dichlorophenoxyacetic Herbicide 115**  Tayeb Wafa, Nakbi Amel, Chaieb Ikbal and Hammami Mohamed

Contents VII

Chapter 17 **Effects of NK-4, a Cyanine Dye**

**with Antioxidant Activities: Attenuation of Neuronal Deficits in Animal Models of Oxidative Stress-Mediated Brain**

**Ischemia and Neurodegenerative Diseases 369** Hitomi Ohta, Kenji Akita and Tsunetaka Ohta

#### **Section 5 Antioxidants 201**

Chapter 17 **Effects of NK-4, a Cyanine Dye with Antioxidant Activities: Attenuation of Neuronal Deficits in Animal Models of Oxidative Stress-Mediated Brain Ischemia and Neurodegenerative Diseases 369**  Hitomi Ohta, Kenji Akita and Tsunetaka Ohta

VI Contents

Chapter 7 **Environmental Pollution and Oxidative Stress in Fish 131** Oksana B. Stoliar and Volodymyr I. Lushchak

**in Citrus by** *Xanthomonas citri* **pv** *citri* **169**

Tiiu Kullisaar, Epp Songisepp and Mihkel Zilmer

Rajagopalan Vijayaraghavan and Anshoo Gautam

**on Secretory Function in Salivary Gland Cells 189**

**Section 4 Biological Factors and Effects 167**

Chapter 9 **Effect of Oxidative Stress**

**Section 5 Antioxidants 201**

Chapter 12 **Flavonoid Treatment**

Chapter 8 **Interference of Oxidative Metabolism**

Robert C. Ebel and Naveen Kumar

Ken Okabayashi, Takanori Narita, Yu Takahashi and Hiroshi Sugiya

Chapter 10 **Probiotics and Oxidative Stress 203**

Chapter 13 **The Effects of Propolis in Animals**

Chapter 14 **Antioxidants in Thai Herb, Vegetable**

Warin Sangkitikomol

Fahmy G. Elsaid

Chapter 16 **Dietary Antioxidants:**

Chapter 15 **Modification by Aqueous Extracts**

Chapter 11 **Diabetes, Oxidative Stress and Tea 223** B. Alipoor, A. Homayouni Rad and E. Vaghef Mehrabany

**for Mustard Agents' Toxicity 249**

**Exposed Oxidative Stress 267** Pinar Tatli Seven, Seval Yilmaz,

Ismail Seven and Gulizar Tuna Kelestemur

**and Fruit Inhibit Hemolysis and Heinz**

**Body Formation in Human Erythrocytes 289**

**of** *Allium kurrat L.* **and** *Ricinus communis L.* **of Cyanide Nephrotoxicity on Balb/C Mice 307**

**From Micronutrients and Phytochemicals**

**on Early Atherosclerosis and Obesity 323**

**to Enzymes – Preventive Effects**

Sylvie Gaillet, Dominique Lacan

and Jean-Max Rouanet

Preface

Free radicals discovered in biological systems in 1950es were immediately suggested to be involved in diseases and aging (Harman, 1956; 1985). The term "free radicals" was later extended to denote a wider group of activated oxygen forms whose activity is higher than molecular oxygen, and were collectively named reactive oxygen species (ROS), which include singlet oxygen, superoxide anion radical, hydrogen peroxide, hydroxyl radical, and many of their derivatives. In 1969, J. McCord and I. Fridovich described the catalytic function for erythrocuprein (hemocuprein) as superoxide dismutase responsible for elimination of the superoxide anion. The information on free radical processes in biological systems allowed Helmut Sies (1985) to systematize "Oxidative stress" and came to denote a disturbance in the prooxidant-antioxidant balance in favor of the former. Recently, we modified this definition as "Oxidative stress is a situation when steady-state ROS concentration is transiently or chronically enhanced, disturbing cellular metabolism and its regulation, and damaging cellular constituents" (Lushchak, 2011b). The last definition included accumulated the up-todate knowledge on the effects of ROS on core and regulatory processes, and underlined the idea on their steady-state level in biological systems. Our understanding of the ROS roles in biological systems has gone through three phases: their appreciation as damaging ones, protection against infections and, finally, signaling and regulatory molecules in diverse biological processes. We can now state that all listed components operate in organisms in concert and are absolutely

Intensive research was invested into discovering whether the environmental factors can affect intracellular ROS steady-state levels. That resulted in understanding that this level may be modified by many external physical, chemical and biological factors. Since it is difficult to register ROS levels *in situ*, these data were mainly gained through indirect methods with the evaluation of levels of ROS-modified molecules of both external and internal origin. Therefore, this book mainly contains the information on oxidative stress induced by physical and chemical factors and a portion of the book

On January 2, 2012, a Google Scholar search for "oxidative stress environment" yielded about 589,000 publication hits, whereas in Scopus and Pubmed databases it yielded 4,428 and 6,302 hits, respectively. We have presented 17 chapters in this book,

includes the information on antioxidants capable to modify ROS levels.

necessary for realization of biological functions.

## Preface

Free radicals discovered in biological systems in 1950es were immediately suggested to be involved in diseases and aging (Harman, 1956; 1985). The term "free radicals" was later extended to denote a wider group of activated oxygen forms whose activity is higher than molecular oxygen, and were collectively named reactive oxygen species (ROS), which include singlet oxygen, superoxide anion radical, hydrogen peroxide, hydroxyl radical, and many of their derivatives. In 1969, J. McCord and I. Fridovich described the catalytic function for erythrocuprein (hemocuprein) as superoxide dismutase responsible for elimination of the superoxide anion. The information on free radical processes in biological systems allowed Helmut Sies (1985) to systematize "Oxidative stress" and came to denote a disturbance in the prooxidant-antioxidant balance in favor of the former. Recently, we modified this definition as "Oxidative stress is a situation when steady-state ROS concentration is transiently or chronically enhanced, disturbing cellular metabolism and its regulation, and damaging cellular constituents" (Lushchak, 2011b). The last definition included accumulated the up-todate knowledge on the effects of ROS on core and regulatory processes, and underlined the idea on their steady-state level in biological systems. Our understanding of the ROS roles in biological systems has gone through three phases: their appreciation as damaging ones, protection against infections and, finally, signaling and regulatory molecules in diverse biological processes. We can now state that all listed components operate in organisms in concert and are absolutely necessary for realization of biological functions.

Intensive research was invested into discovering whether the environmental factors can affect intracellular ROS steady-state levels. That resulted in understanding that this level may be modified by many external physical, chemical and biological factors. Since it is difficult to register ROS levels *in situ*, these data were mainly gained through indirect methods with the evaluation of levels of ROS-modified molecules of both external and internal origin. Therefore, this book mainly contains the information on oxidative stress induced by physical and chemical factors and a portion of the book includes the information on antioxidants capable to modify ROS levels.

On January 2, 2012, a Google Scholar search for "oxidative stress environment" yielded about 589,000 publication hits, whereas in Scopus and Pubmed databases it yielded 4,428 and 6,302 hits, respectively. We have presented 17 chapters in this book, covering several important aspects of environmentally induced oxidative stress and its prevention by antioxidants. Since oxidative stress seems to be an inevitable component of virtually all stresses that are strong enough, the book provides the interested readers with information needed to recognize this.

Preface XI

The next section is devoted to induction of oxidative stress by biological factors. Diverse pathogens invading the host organism are attacked by the immune system equipped by machinery to produce reactive species. R. C. Ebel and N. Kumar investigated the involvement of reactive oxygen species in combating *Xanthomonas citri pv citri* (Xcc), causing citrus canker in *Citrus sp*. and found that pathogen-induced oxidative stress was differently expressed in different representatives of the genera studied. K. Okabayashi et al. were able to demonstrate that ethacrynic acid, a thiolmodulating reagent, inhibited amylase release induced by β-adrenergic agonist in rat parotid acinar cells and the effect was independent of depletion of glutathione in the cells. The authors concluded that the inhibitory effect of ethacrynic acid on amylase release induced by β-adrenergic agonist was caused by the thiol-modulation of β-

It is very attractive to use antioxidants to prevent ROS-induced modification of organisms' functions. Intuitively developed at the beginning of ROS investigation in living organisms, it looked promising to use them for prophylactics and treatment of ROS-modulated damages. However, the promises were not realized and it became clear that there are no absolutely direct links between ROS-induced changes and pathologies. The last section of the book presents a broad discussion of positive effects of diverse antioxidants. The Estonian team led by T. Kullisaar provides an interesting topic – after short surveys on probiotics and oxidative stress they share extensive information on the potential use of different probiotics in functional foods and capsules that may be helpful to combat oxidative stress related to many pathologies, like cardiovascular diseases, metabolic syndrome, allergy, atopic dermatitis, radiationinduced problems in the intestinal tract. Diabetes is a very common human disease, which, in addition to health problems caused, is accompanied by many complications related with oxidative stress and the system character of the pathology therefore clearly needs specific approaches. It is very attractive to use a food stuff instead drugs and B. Alipoor et al. describe the potential of one of the most common drinks, tea, with health benefits particularly for diabetes and related complications. Sulphur mustard as a bifunctional alkylating agent readily reacts with a variety of macromolecules including nucleic acids, proteins and lipids, as well as small molecular mass metabolites such as glutathione, which is in the focus of chapter written by R. Vijayaraghavan and A. Gautam. Since sulphur mustard also induces oxidative stress, antioxidants can be useful and the authors analyze available data on the use of flavonoids, particularly from *Hippophae rhamnoides.* Bee products accompanied people since ancient times and only now do we start to understand the molecular mechanisms of many processes modulated by these products. Therefore, P. Tatli Seven provide an extensive analysis of beneficial properties of propolis with the focus on its antioxidant, antimicrobial, anti-inflammatory and antitumor effects. The antioxidant potential of 152 samples of Thai fruits, vegetables and herbs, and 33 brands of tea was measured by W. Sangkitikomol and this study shows that the products are a good source of compounds with health benefits. Since the toxicity of cyanide is associated with the induction of oxidative stress, F. G. Elsaid suggests and proves that it can be

adrenergic receptors.

The Introduction section (V. I. Lushchak) covers general aspects of oxidative stress theory and briefly analyses potential ways of oxidative stress induction by environmental factors – stimulation of ROS production and depletion of antioxidants. The role of antioxidants is also highlighted.

The book is divided into four parts. The first section, entitled "Physical Factors" demonstrates the induction of oxidative stress by exercise, light and temperature fluctuations. The chapter written by V. Lj. Jakovljevic and colleagues extensively introduces the biology of reactive oxygen and nitrogen species, measurement of redox status, levels of superoxide anion radical, hydrogen peroxide, glutathione, lipid peroxides, activities of superoxide dismutase and catalase, and then demonstrates that exercise may increase the production of ROS and modify redox status. Interestingly, it has been demonstrated that perturbations of free radical processes depend on the intensity and type of exercise, as well as specialization of athletes and their physical state. Different light types possessing high energy can also induce damage to cellular components, even in specialized organs. K. Engelmann et al. described the operation of human retina, ROS-related processes, protective role of specific parts of the light spectrum and retina protection by tinted intraocular lenses in detail. The next two experimental chapters deal with oxidative stress induced by temperature changes – in fungi and plants. Using two Antarctic fungi, *Penicillium sp.* and *Aspergillus glaucus*, N. Kostadinova et al. demonstrated a relationship between cold shock and oxidative stress evidenced by an increased level of oxidized proteins and activation of antioxidant enzymes. Since abscisic acid may increase freezing tolerance of plants, M. E. Mora-Herrera et al. were able to demonstrate that ther decrease in temperature affected the level of hydrogen peroxide and catalase isoforms in potato microplants, which was related to tolerance to low temperatures.

The induction of oxidative stress by chemical factors is presented in the second section of the book. Ions of metals may induce oxidative stress in at least two ways – entering Fenton reaction and replacing other metal ions in their binding centers (Valko et al., 2007). The detailed description of toxicokinetics of lead and cadmium, induction and role of oxidative stress in neurochemical changes in the hypothalamus and pituitary of F1 generation PND 56 male and female rats are presented by P. Pillai et al. Herbicides are well known inducers of oxidative stress and many mechanisms were described in this case. 2,4-Dichlorophenoxyacetic herbicide is one of the broadly used ones, and W. Tayeb et al. describe the general phenomenology and potential mechanisms of induction of oxidative stress in different organisms. The chapter by O. B. Stoliar and V. I. Lushchak is devoted to analysis of oxidative stress induced in fish by different environmental pollutants.

The next section is devoted to induction of oxidative stress by biological factors. Diverse pathogens invading the host organism are attacked by the immune system equipped by machinery to produce reactive species. R. C. Ebel and N. Kumar investigated the involvement of reactive oxygen species in combating *Xanthomonas citri pv citri* (Xcc), causing citrus canker in *Citrus sp*. and found that pathogen-induced oxidative stress was differently expressed in different representatives of the genera studied. K. Okabayashi et al. were able to demonstrate that ethacrynic acid, a thiolmodulating reagent, inhibited amylase release induced by β-adrenergic agonist in rat parotid acinar cells and the effect was independent of depletion of glutathione in the cells. The authors concluded that the inhibitory effect of ethacrynic acid on amylase release induced by β-adrenergic agonist was caused by the thiol-modulation of βadrenergic receptors.

X Preface

covering several important aspects of environmentally induced oxidative stress and its prevention by antioxidants. Since oxidative stress seems to be an inevitable component of virtually all stresses that are strong enough, the book provides the interested

The Introduction section (V. I. Lushchak) covers general aspects of oxidative stress theory and briefly analyses potential ways of oxidative stress induction by environmental factors – stimulation of ROS production and depletion of antioxidants.

The book is divided into four parts. The first section, entitled "Physical Factors" demonstrates the induction of oxidative stress by exercise, light and temperature fluctuations. The chapter written by V. Lj. Jakovljevic and colleagues extensively introduces the biology of reactive oxygen and nitrogen species, measurement of redox status, levels of superoxide anion radical, hydrogen peroxide, glutathione, lipid peroxides, activities of superoxide dismutase and catalase, and then demonstrates that exercise may increase the production of ROS and modify redox status. Interestingly, it has been demonstrated that perturbations of free radical processes depend on the intensity and type of exercise, as well as specialization of athletes and their physical state. Different light types possessing high energy can also induce damage to cellular components, even in specialized organs. K. Engelmann et al. described the operation of human retina, ROS-related processes, protective role of specific parts of the light spectrum and retina protection by tinted intraocular lenses in detail. The next two experimental chapters deal with oxidative stress induced by temperature changes – in fungi and plants. Using two Antarctic fungi, *Penicillium sp.* and *Aspergillus glaucus*, N. Kostadinova et al. demonstrated a relationship between cold shock and oxidative stress evidenced by an increased level of oxidized proteins and activation of antioxidant enzymes. Since abscisic acid may increase freezing tolerance of plants, M. E. Mora-Herrera et al. were able to demonstrate that ther decrease in temperature affected the level of hydrogen peroxide and catalase isoforms in potato microplants,

The induction of oxidative stress by chemical factors is presented in the second section of the book. Ions of metals may induce oxidative stress in at least two ways – entering Fenton reaction and replacing other metal ions in their binding centers (Valko et al., 2007). The detailed description of toxicokinetics of lead and cadmium, induction and role of oxidative stress in neurochemical changes in the hypothalamus and pituitary of F1 generation PND 56 male and female rats are presented by P. Pillai et al. Herbicides are well known inducers of oxidative stress and many mechanisms were described in this case. 2,4-Dichlorophenoxyacetic herbicide is one of the broadly used ones, and W. Tayeb et al. describe the general phenomenology and potential mechanisms of induction of oxidative stress in different organisms. The chapter by O. B. Stoliar and V. I. Lushchak is devoted to analysis of oxidative stress induced in fish by different

readers with information needed to recognize this.

which was related to tolerance to low temperatures.

environmental pollutants.

The role of antioxidants is also highlighted.

It is very attractive to use antioxidants to prevent ROS-induced modification of organisms' functions. Intuitively developed at the beginning of ROS investigation in living organisms, it looked promising to use them for prophylactics and treatment of ROS-modulated damages. However, the promises were not realized and it became clear that there are no absolutely direct links between ROS-induced changes and pathologies. The last section of the book presents a broad discussion of positive effects of diverse antioxidants. The Estonian team led by T. Kullisaar provides an interesting topic – after short surveys on probiotics and oxidative stress they share extensive information on the potential use of different probiotics in functional foods and capsules that may be helpful to combat oxidative stress related to many pathologies, like cardiovascular diseases, metabolic syndrome, allergy, atopic dermatitis, radiationinduced problems in the intestinal tract. Diabetes is a very common human disease, which, in addition to health problems caused, is accompanied by many complications related with oxidative stress and the system character of the pathology therefore clearly needs specific approaches. It is very attractive to use a food stuff instead drugs and B. Alipoor et al. describe the potential of one of the most common drinks, tea, with health benefits particularly for diabetes and related complications. Sulphur mustard as a bifunctional alkylating agent readily reacts with a variety of macromolecules including nucleic acids, proteins and lipids, as well as small molecular mass metabolites such as glutathione, which is in the focus of chapter written by R. Vijayaraghavan and A. Gautam. Since sulphur mustard also induces oxidative stress, antioxidants can be useful and the authors analyze available data on the use of flavonoids, particularly from *Hippophae rhamnoides.* Bee products accompanied people since ancient times and only now do we start to understand the molecular mechanisms of many processes modulated by these products. Therefore, P. Tatli Seven provide an extensive analysis of beneficial properties of propolis with the focus on its antioxidant, antimicrobial, anti-inflammatory and antitumor effects. The antioxidant potential of 152 samples of Thai fruits, vegetables and herbs, and 33 brands of tea was measured by W. Sangkitikomol and this study shows that the products are a good source of compounds with health benefits. Since the toxicity of cyanide is associated with the induction of oxidative stress, F. G. Elsaid suggests and proves that it can be reduced by the application of aqueous extracts of *Allium kurrat* and *Ricinus communis* which possess antioxidant properties. Due to high sugar and fat diets and sedentary lifestyles, modern people are frequently subjected to atherosclerosis and obesity, which are important risk factors for metabolic syndrome and greatly predispose individuals to liver diseases, cardiovascular disease, type 2 diabetes, dyslipidemia, hypertension and numerous cancers, and is associated with markedly diminished life expectancy. The French team (S. Gaillet, D. Lacan, J.-M. Rouanet) presents results of titanic systematic work to identify the beneficial diets and find a broad set of diary foods and beverages possessing antioxidant properties and helping to combat the mentioned pathologies. These products are fresh and possessed fruits grapes, and berries, preparations from them as well as selenium-enriched microalgae, algal and fungal polysaccharides. Recently, while screening more than 250 cyanine dyes for their neurotrophin-like activity, the compound called NK-4 and some related compounds were found to be potent neurotrophic agents for the promotion of growth and differentiation of neuronal rat adrenal pheochromocytoma cell line PC12. NK-4 is a divalent cationic pentamethine trinuclear cyanine dye that contains three quinolinium rings, N-alkyl side chains, and two iodine anions. In the last chapter of the book, the Japanese team (H. Ohta, K. Akita & T. Ohta) summarized the data on the biological effects in different models and found that NK-4 possesses free radical-scavenging activity, neuroprotective against various cytotoxic stresses, neuroprotective effects against β-amyloid (Aβ) toxicity, and intracellular signaling. Therefore, the authors suggest that this dye can be used to protect animal organisms against neurodegeneration**.**

This book is expected to be interesting to experts in the field of basic investigations of reactive oxygen species and oxidative stress, as well as to practical users in the diverse fields like environmental sciences, medicine, and toxicology.

> **Prof. Dr. Volodymyr I. Lushchak**  PhD, DSc, Department of Biochemistry and Biotechnology, Vassyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine


**Chapter 7 103**

Preface

The COVID-19 pandemic has had myriad negative consequences around the globe. As of December 2022, there were 649,038,437 confirmed cases and 6,645,812 deaths worldwide. In Mexico, for example, there were 7,222,611 confirmed cases and 331,030

The pandemic caused much fear, especially when secondary effects such as anosmia, dysgeusia, coagulation disorders, stroke, and cardiovascular problems that could lead to death began to be reported. In addition, there were reports of other sequelae such as pulmonary fibrosis, mental disorders, kidney problems, and more. This book provides a comprehensive overview of post-COVID effects on human health. Chapter 1 discusses treatments of COVID-19 and vaccines and examines their relationship to post-COVID sequelae. Chapter 2 examines Multisystemic Inflammatory Syndrome in children (MIS-c); it was very important in children with COVID-19. Post-COVID-19

The relationship between mental health and COVID-19 was reviewed and analysed in Chapter 4; it is suggested that mental health in the aftermath of the pandemic should be closely monitored. This issue was very important because the threat of being infected by SARS-CoV-2 generated a lot of fear in the world population. In addition to those who were infected, anguish and emotional disorders were generated due to the fear of facing a serious illness or death and in those around them, isolation and not performing the usual tasks also cause disturbances in mental health. Chapter 5 reviewed hydro electrolytic alterations that could be mediated by antidiuretic hormones. Chapter 6 presents the effects on mental health in oncology mental health works, and finally, chapter 7 reviews Covid-19 in Mexico, where there were high

I wish to thank the staff at IntechOpen, especially the Publishing Process Manager, Ms. Dolores Kuzelj, for her excellent support throughout the publication process. I am

**Dr. Nicolas Padilla-Raygoza**

Guanajuato, Mexico

Directorate of Teaching and Research,

Department of Research and Technological Development,

Institute of Public Health from Guanajuato State,

also grateful to the contributing authors for their excellent chapters.

stroke and rehabilitation were reviewed in Chapter 3.

numbers of cases as well as deaths due to the virus.

deaths [1].

Post-COVID-19 Condition and Its Presence in Mexico *by Efraín Navarro-Olivos, Gilberto Flores-Vargas, Guadalupe Irazú Morales-Reyes, Jéssica Paola Plascencia-Roldán, María de Jesús Gallardo-Luna and Nicolás Padilla-Raygoza*


**8. Conclusions**

This research proposes a simple low-cost PMMS utilizing a smartphone app and Google Earth for small to intermediate cities in developing countries. The system uses an Android application installed on a smartphone to measure the road surface roughness based on GPS and accelerometer sensors. Google Earth is utilized for the visual illustration of the road conditions and other analyses.

The proposed system was implemented in Hajjah, a city in Yemen. The results reveal that IRI measurements performed by the app and Google Earth can provide a low-cost solution for cities such as Hajjah to manage their road network at an acceptable level. Google Earth is an excellent tool that can display road network conditions and all other attributes related to road maintenance management.

The following conclusions can be drawn from these results:

**Author Contributions:** Conceptualization, formal analysis, funding acquisition, investigation, methodology, project administration, and resources, A.I.A.-M.; visualization, A.I.A.-M. and A.H.A.-Q.; writing— original draft, A.I.A.-M. and A.H.A.-Q.; writing—review and editing, A.H.A.-Q. and A.I.A.-M. All authors have read and agreed to the published version of the manuscript.

**Funding:** The authors would like to acknowledge the support provided by the Researchers Supporting Project Number (RSP2022R424), King Saud University, Riyadh, Saudi Arabia.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable. **Data Availability Statement:** Available upon request and with regulations.

**Acknowledgments:** The authors acknowledge King Saud University for providing the funding for this research paper.

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


*Immunohistochemical Analysis*

A stepwise rehydration of the brain sections was conducted, followed by a heat-induced antigen retrieval in 10 mM citrate bu ffer (pH 6.0) including 0.05% Tween-20 (Sigma-Aldrich, Taufkirchen, Germany). After rinsing, sections were incubated for 5 min in 0.6% H2O2 (Sigma-Aldrich) in PBS (0.1 M; pH = 7.3) in order to block endogenous peroxidases. Sections were rinsed and incubated for 30 min in PBS containing 1% bovine serum albumin (PBS-B) and 5% normal goat serum (NGS, Sigma-Aldrich) to prevent unspecific binding of the antibody. After subsequent rinsing, sections were incubated overnight at 4 ◦C in PBS-B containing 1% NGS and the primary antibody (anti-human Aβ 82E1 mouse IgG MoAb 1:1000, IBL international, Hamburg, Germany). Rinsing was followed by an incubation with goat anti-mouse IgG H&L Biotin (1:1000, Abcam, Berlin, Germany) in PBS-B containing 1% NGS for one hour. Sections were rinsed followed by a 1-h incubation with avidin-biotin conjugate in PBS (ABC; Vectastain Elite ABC HRP Kit, Linaris, Dossenheim, Germany). After another rinsing step, sections were

treated with 3,3-diaminobenzidine tetrahydrochloride (DAB; Sigma-Aldrich) in water (0.2 mg/mL; pH = 7.6) for 10 min. The immunostaining was then developed by adding 50 μL H2O2 to a final concentration of 0.006%, incubating for another 10 min. The reaction was stopped by rinsing in ice-cold distilled water followed by a counterstaining using Mayer's hematoxylin (Morphisto, Frankfurt am Main, Germany). Sections were finally dehydrated and covered with Pertex (Medite). We digitized appropriate sections using a Nicon Eclipse Ni-E microscope (Nikon Instruments Europe BV, Amsterdam, Netherlands). Whole brain images were taken at a final magnification of 100x and the area occupied by plaques in several regions of interest (ROI; Table A2) was analyzed using the color segmentation plugin (Daniel Sage, Biomedical Imaging Group, EPFL, http://bigwww.epfl.ch/sage/soft/colorsegmentation/) for ImageJ software (National Institute of Health, Bethesda, MD, USA). Only animals of the first cohort were immunohistochemically investigated in this study.

**Table A2.** Regions of interest (ROI) in different cortical and hippocampal areas.

## *Preclinical Quality Parameters*

Several aspects were considered to ensure the quality of the applied methodologies and resulting data. These points are in accordance with initiatives such as EQIPD ("European quality in preclinical data"; https://quality-preclinical-data.eu/). The aim of EQIPD is broadly to implement various quality improving measures in order to enhance the reproducibility of preclinical data [63]. In the present study, we performed a power calculation to estimate the needed group size (http://www.biomath.info/power/). The resulting total amount of 112 animals was tested in two consecutive cohorts. Nine animals were lost during the course of the whole study. In terms of translatability, we have decided to include both male and female animals in the experiments, since Alzheimer's disease affects both sexes in the clinical context, with a higher rate in women than in men [48]. In general, female animals are largely underrepresented in neuroscience research [82]. Randomization was applied at several stages along the study course. Mice were initially allocated to the home cages according to a random list (https://www.random.org/) and target holes in the Barnes maze were set randomly. Besides, drinking corners in the IntelliCages as well as the stimulus mice in the social interaction test were also assigned randomly. A within-cage randomization between groups was not applicable in this case because every mouse matched strictly to its adequate experimental diet. All animals were regularly pre-handled and transferred to the experimental rooms at least half an hour before behavioral analysis. Blinding of the experimenter in order to prevent detection bias was not performed here, because in all behavioral tests automated outcome assessment was applied (via EthoVision XT, IntelliCage and Touchsreen software). However, blinding was performed during the immunohistochemical analysis. Here, a second experimenter marked the ROI in the images without being aware of animal ID or experimental group. Furthermore, an automated animal management software as well as an electronic lab-book were used throughout the study. Standard operating procedures had been written prior to the experimental procedures.


*Article* **Economics of Waste Prevention: Second-Hand Products in Germany**

**Henning Wilts \*, Marina Fecke and Christine Zeher**

Wuppertal Institute for Climate, Environment and Energy gGmbH, 42103 Wuppertal, Germany<EMAIL_ADDRESS>(M.F<EMAIL_ADDRESS>(C.Z.)

**\*** Correspondence<EMAIL_ADDRESS>
**Abstract:** Reuse is still seen as a "niche phenomenon" and consumers seem to waste economic opportunities linked to buying and selling second-hand products. For this reason, this paper focuses on incentives and barriers to sell and buy second-hand products, as indicated in the literature, and applies a theoretical framework of transaction costs to explain the existing consumption patterns. For this paper, a representative online survey was conducted in which 1023 consumers in Germany participated, age 16 and older. The data were analyzed for statistically significant deviations between different groups of economic actors selling or buying second-hand products. Results show that valuable unused products exist in households, but barriers such as uncertainties about the reliability of the buyer or the quality of the product hinder the transition into sustainable consumption. Different forms of transaction costs are important explanatory variables to explain why consumers nevertheless predominantly buy new products, although they are aware that second-hand would save money and make an individual contribution to climate protection.

**Keywords:** circular economy; second-hand; reuse; transaction costs

#### **1. Introduction**

Against the background of steadily increasing consumption of natural resources and environmental burdens caused by the currently dominant linear patterns of production and consumption, circular economy approaches have raised significant attention in scientific literature and among policy makers (e.g., European Commission 2020). The transition towards a circular economy in which the value of products and raw materials are contained at the end of their use phase, is seen as a crucial precondition for an absolute decoupling of resource use and economic wellbeing, e.g., achieving the climate targets agreed on in the Paris Accord.

Although many circular economic strategies focus on optimized recycling processes, the European Commission's Circular Economy Action Plan places a specific emphasis on the reuse of products that are no longer needed (European Commission 2020). From an environmental perspective and thus according to the waste hierarchy, reuse offers higher resource saving potentials than recycling—a large part of the necessary efforts in the production phase of products can be avoided and only in a very few cases; e.g., a significantly reduced energy consumption of newer products would overcompensate these advantages (Von Gries 2020). Specific quantification of saved resources or mitigated GHG emissions depends on the specific framework conditions, e.g., to what extent second-hand products actually replace virgin products (Keith 2011). In addition, in terms of cost savings and other socioeconomic objectives, reuse of products seems to be an obvious solution for products that are no longer wanted. Taking the example of packaging, switching to 20% reusable solutions could lead to USD 10 billion of business opportunities (Ellen MacArthur Foundation 2019), according to Rreuse, an European association for reuse, 296 new jobs could be created by treating only 10,000 tons of municipal solid waste (Rreuse 2015).

**Citation:** Wilts, Henning, Marina Fecke, and Christine Zeher. 2021. Economics of Waste Prevention: Second-Hand Products in Germany. *Economies* 9: 74. https://doi.org/ 10.3390/economies9020074

Academic Editor: George Halkos

Received: 8 April 2021 Accepted: 7 May 2021 Published: 12 May 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

However, despite this consideration of reuse as a win–win opportunity that should align environmental and economic objectives of a circular economy, product reuse is actually a "niche phenomenon" (European Environment Agency 2018) of limited economic relevance for most product groups. According to the European Environment Agency´s progress report on waste prevention, the total turnover of the European second-hand sector is below 1% of the total retail sector and below 0.01% of Europe's gross added value. Official statistics exist for only a few product groups, such as electronic and electrical products, and only a few countries show a share of reused products of more than 1% (Eurostat 2020). Taking Germany as an example, a study initiated by the Environmental Protection Agency estimated an annual market volume of just 4 kg per capita, including online platforms, e.g., eBay (Von Gries et al. 2017).

Against this background, this paper takes the gap between pure market opportunities and the reality of reuse as a "niche phenomenon" as the starting point to focus on barriers for reuse. It builds up on several papers that have focused on specific drivers or barriers, but to the authors' understanding, it does not provide a systematic framework on how these barriers translate into reduced economic incentives to sell or buy second-hand products. Farooq Baqal and Abdulkhaleq (2018) highlighted that second-hand products in general are gaining more prominence because "products produced today will be outdated tomorrow and in order to go for an advanced version, there is a need to sell used products". Previous research on barriers for reuse has, e.g., highlighted differences between various products groups, such as whether products have traces of previous owners (Edbring et al. 2016). Behrendt et al. (2011) identified five types of eBay users who trade based on very different incentives, inter alia so-called "prosumers" that already consider the reselling potential of products when buying them. On average, Mukherjee et al. (2020) also identified economic incentives as an important driver of using second-hand products. Such incentives become even more relevant as the purchase of previously used merchandise has been transformed "from a second-class act" into a worldwide fashion trend related to buying something "cool" and "stylish"" (Hristova 2019). Klug et al. (2015), inter alia, highlighted the issue of trust as an important barrier for purchasing second-hand products.

In order to provide new insights on the actual relevance of incentive structures, this paper draws on economic transaction cost theories, a specific branch of literature within the so-called new institutional economics (NIE). The focus here is on the costs of using market mechanisms, e.g., for economic transactions such as the sale or purchase of second-hand products. This perspective contradicts the simplistic neoclassical assumptions that every market participant is fully informed about everything, now and in the future—at zero costs (Simon 1959; Coase 1998). Instead, so-called transaction costs occur, related to the gathering, validation, and processing of information, and can lead to path dependencies in which, from an economic point of view, inferior options (i.e., buying new products) have higher market shares than they should have in an optimal equilibrium, simply because standards and routines have evolved over decades to minimize such transaction costs (Yousuf 2017). Following Alston and Gillespie (1989), this paper differentiates transaction costs as analytical variables based on the different phases of market transactions: costs of finding suitable business partners, costs of negotiating contracts, and finally costs of monitoring whether the agreed products or services actually have the contractually agreed quality. Vakis et al. (2003) identifies these empirical approaches as an important research gap in the area of new institutional economics.

The aim of this paper is to contribute to current research by first providing an empirical basis for the actual relevance of the incentives and barriers mentioned in the literature above, and second, by applying a theoretical framework of transaction costs for both sellers and buyers of second-hand products to explain the gap described: How to explain the fact that consumers seem to waste economic opportunities linked to buying and selling second-hand products? How can the concept of transaction costs be operationalized in order to show its relevance for market exchanges?

For this purpose, the paper is structured as follows: Section 2 describes the materials and methods used—the data gathering and the theoretical framework for its analysis. Section 3 shows the results, Section 4 discusses the conclusions that can be drawn from the empirical results, and the last section draws conclusions, particularly regarding efficient policy formulation to support reuse, and further research needed to develop a consistent theoretical framework for the economics of waste prevention.

#### **2. Methodology**

For this paper, a representative online survey was conducted in which consumers in Germany participated, age 16 and older (Wilts and Fecke 2020). The participants were selected based on a standardized consumer panel in order to allow statistically significant conclusions differentiating gender, age groups, living conditions (urban, periurban, and rural) and spatial location within Germany (north, south, east, west). The participants were approached in September 2020 and thus between the two major COVID-19 waves and linked shutdowns, which might have influenced responses due to economic uncertainties or increased importance, e.g., hygienic concerns (Sueßbauer et al. 2020). On average, it took the participants 12 min to fill in the questionnaire; only completed questionnaires were taken into account.

The data sample included 1023 persons, selected from a predefined panel allowing for weighting of variables listed above in relation to national mean values. The panel of interviewees had a share of 52% females, 53% were age 50 and older, 79% were living in the western part of Germany, 32% had a university degree, and 38% indicated a net household income of EUR 2500 or higher. Fifty-one percent of the interviewees had bought at least second-hand item during the last 12 months and 46% offered products for reuse.

The questionnaire was developed in cooperation with eBay Kleinanzeigen, which is one of the largest online platforms for second-hand products in Germany. It included a total of 31 questions, 9 of which referred to general demographic aspects of the participant. The remaining 22 questions focused on selling used products, the purchase of second-hand products, and perceptions of climate and sustainability issues. The interviewees were given five different options to assess their agreement with specific statements (fully agree, partly agree, etc.). In a last step, the answers were weighted with regard to the factors indicated above. For the analysis, the answers were structured using cross-correlation analysis in order to show deviations from average answer patterns.

Based on the conceptional literature on transaction costs, the following matrix structure in Table 1 was developed that structures potential transaction costs that might hinder the market development for second-hand products. The framework differs between the phases of exchange as described in Section 1, specifically for buyers and sellers of secondhand products. This Table 1 was used to develop the questionnaire for the empirical part of the research presented in the section that follows.

**Table 1.** Transaction costs in different phases of market exchange.

#### **3. Results**

The following presents the results of the online survey that are divided into three parts: data on selling (Section 3.1) and buying second-hand products (Section 3.2); general attitudes on sustainability aspects as drivers for sale/purchase second-hand products (Section 3.3); and the final step (Section 3.4), which focuses on the relevance of specific barriers based on a statistical analysis of these data.

#### *3.1. Selling Second-Hand Products*

The survey results show that consumers own a significant number of products that they consider no longer used or needed. When asked about specific product groups that the survey interviewees have not used in at least 12 months but still nevertheless keep in their households, 62% mentioned CDs, DVDs, or Blue Ray Discs, 58% indicated books, and 57% clothing and shoes. Interestingly, 6% also mentioned cars as completely unused property. Figure 1 shows how the participants assessed the total value of these items that were unused for at least twelve months. The majority of participants estimated the value to be between EUR 250 and 499; nevertheless, the percentages are rather equally distributed between less than EUR 100 and up to EUR 2499, resulting in an average amount of EUR 1289. It should be noted that such self-assessments bear significant uncertainties, e.g., regarding the value of product depreciation years after the actual purchase. Nevertheless, the results in terms of number and value of products are consistent with previous analyses, e.g., Huisman et al. (2017).

Taking into account the economic potential that a household could realize by selling these unused products, it seems surprising that only 46% of participants reported selling at least one of these products, and only 30% sell one or more products at least every three months. Twenty-three percent of consumers, asked in the survey, do not get rid of products at all, and thus these items occupy an increasing amount of space in their flats or houses. Forty-seven percent of them simply discard unused products as waste, despite their economic value—this refers mainly, but not only, to broken products. When asked why they do not take advantage of the opportunity to turn such products into additional income, 12% answered that they are not aware of channels for selling used products, 24% mentioned the necessary efforts as an important barrier. Concerning this additional effort, 49% emphasized the time required, 34% lack information about the residual value of the products they want to sell, 32% have trust issues with potential buyers and are afraid of fraud, and 31% noted that communication with potential buyers simply takes too much time.

**Figure 1.** Estimated average value of unused products in the household. Source: authors' results.

#### *3.2. Buying Used Products*

In a second part, the participants were asked about their role as purchasers of used products. Of the 1023 interviewees, the majority indicated economic incentives as important advantages of buying second-hand products in comparison to virgin products: 56% agreed that they were able save costs and 36% indicated that they would not have afforded the products at the original retail price. Environmental benefits and avoiding unnecessary wastage of natural resources was indicated by 42%, and a third key driver seems to be the availability of products that are no longer for sale (34%).

Despite these economic incentives, only 29% of the survey participants bought more than one used product during the last twelve months. The results show that a large percentage of second-hand purchases is done by a relatively small group of participants who buy a product on a weekly or even daily basis. Table 2 illustrates the important barriers that were recorded—most refer to uncertainties about the reliability of the buyer or the quality of the product. Consistent with the abovementioned analysis by Hristova (2019), only 4% mentioned a general reluctance towards second-hand products as something that is only relevant for those who cannot afford new products. Potential buyers do not seem to be held back by unjustified prices, but by specific risks and uncertainties that would require them to invest more time in the validation of given information on the products for sale. Taking these barriers into account, the interviewees mentioned various product groups that less than a quarter would even consider buying second-hand. This includes inter alia smartphones, large electronic appliances, or car spare parts—all are considered as particularly resource-intensive and often contain critical raw materials (Sander et al. 2019).

**Table 2.** Key barriers in buying used products. Source: authors' results.

#### *3.3. Attitudes towards Sustainability and Climate Protection*

A third group of questions referred to the personal attitudes towards sustainable consumption and climate protection and their relevance for the willingness to buy secondhand products. Table 3 shows the significantly different answers of those who actually bought a second-hand product during the last twelve months and those who completely focused on buying virgin products. Here, 66% compared to only 28% who did not buy a second-hand product agreed with the statement that used products are an attractive alternative to new products; 55% compared to 25% mentioned that buying second-hand products is seen as an element of sustainable consumption.

However, even of those interviewees who did not buy a single second-hand product in the last year, 55% agreed that second-hand products are good for the environment. There is also little difference between the shares of interviewees who mentioned that sustainable consumption should include buying less—it could be argued that this is an indication to second-hand as a consistency rather than a sufficiency strategy for sustainability. Almost half of the survey participants do not seem to see a necessity to question consumption patterns as long as the products purchased have a lower environmental footprint (Sachs 2015). Those consumers who already bought a used product in the past also indicated a higher willingness to buy more second-hand in the future (63% compared to 30%).

**Table 3.** Agreement to specific statements related to sustainability depending on previous purchases of second-hand products. Authors' results.

#### *3.4. Relevance of Specific Barriers for Reuse*

Based on these data, Tables 4 and 5 show an analysis of the relevance of specific barriers for (a) buying and (b) selling second-hand products. For this analysis, data on relevant barriers were checked for statistically significant deviations between regular buyers/sellers (more than four products per year) and those who indicated not to buy/sell any second-hand products. The table highlights deviations with a β error of *p* ≥ 0.1.

The results highlight that different barriers seem to be of different relevance based on the frequency of selling/buying second-hand products. Interestingly, the perceived relevance of some barriers seems to increase, whereas others seem to decrease when consumers gain experiences with second-hand products. Experienced consumers put a stronger emphasis on insufficient descriptions of second-hand products and in general more often confirmed that buying second-hand products is more time consuming than regular purchases of new products. On the other hand, concerns about hygienic conditions of products and a general reliance on new products seem to decrease when consumer purchase second-hand products on a more regular basis. Concerning selling secondhand products, it is not surprising that the challenge of finding suitable market places is perceived as less relevant when consumers are used to offering their products more than four times a year. In addition, the general mistrust in buyers seems to decrease. On the other hand, experienced sellers emphasized the time-consuming communication with potential consumers.

**Table 4.** What are the three most significant disadvantages of buying used?

**Table 5.** What are the three largest barriers to selling used products?

#### **4. Discussion**

The empirical results of the online survey and its analysis confirm various points of the existing literature on drivers/barriers for second-hand products. There seems to be a high willingness and acceptance amongst consumers to consider second-hand products as an alternative to buying new products—with economic incentives and environmental benefits as key drivers, see (Klug et al. 2015; Mukherjee et al. 2020; Budică et al. 2015). In this regard, the survey focusing on Germany seems to be consistent with international data (Bortoleto 2015). It should nevertheless be taken into account that overall reuse figures in Germany are quite low compared to neighbor countries such as, e.g., Belgium and France, inter alia due to high shares of exports for second hand goods (Borusiak et al. 2020). This specific gap between intention and actual behavior also seems to confirm the guiding research hypothesis on different forms of transaction costs as an important explanatory variable in order to explain why consumers nevertheless predominantly buy new products

although they are aware that second-hand would save money and make an individual contribution to climate protection, also taking into account the ratio of price and depreciated value of the product (OECD 2006).

The data presented seem to indicate that these general conclusions are based on perceptions that clearly diverge between different subgroups: younger cohorts emphasized the economic advantages and less the environmental benefits; they also indicate a lower willingness to modify consumption patterns for environmental objectives such as resource or climate protection compared to interviewees aged 60 and older, for example. This questions conclusions, e.g., by Rubik et al. (2019), who highlighted the increasing environmental awareness especially of children and younger people. Despite such differences between different social subgroups, the overwhelming majority of interviewees support the concept of extending use phases of products by reuse and in practice buy only a small share of previously used products and also do not offer significant amounts of products for sale, although they are unused and of considerable monetary value, see Urba ´nski and Ul Haque (2020).

Concerning the research question of this paper, the consideration of transaction costs leads to plausible insights into certain drivers and barriers for the second-hand market, but of course raises the question of quantifying these costs for the use of the market mechanism. This issue has been highlighted by several authors who criticize the fact that transaction costs tend to be measured rather indirectly as divergence from an assumed optimal market equilibrium: "while the body of descriptive and theoretical literature on transactions costs is extensive, the empirical literature has been lagging" (Vakis et al. 2003). Especially, when transaction costs are prohibitively high and, in our case, virgin products offer a viable alternative, it is challenging to assess the absolute value of these additional costs.

The analytical perspective of transaction costs seems to be helpful for explaining this gap (Yousuf 2017). The costs of gathering and validating information on exchange partners and specific products seem to be of such relevance that those actors who focus on economic advantages decide that virgin products offer the better cost–benefit ratio. Furthermore, even those actors indicating environmental reasons as an important driver for buying/selling second-hand seem to conclude that other options to reduce their resource or climate footprint offer easier and thus more efficient ways to save the planet. The analysis presented here adds a dynamic perspective on such transaction costs. The relevance of specific barriers for reuse seems to change if market actors—as buyers as well as sellers engage in more frequent transactions, including second-hand products. With an increasing number of products that are offered/bought every year, some barriers caused by such transaction costs gain in relevance, others are perceived as less important.

#### **5. Conclusions**

This paper analyses the relevance of specific transaction costs as a barrier for market transactions for second-hand products, and thus for the development of a reuse market segment that could contribute to resource conservation and climate change mitigation. Obviously, transaction costs are only one variable among many that determine the decision to sell/buy second-hand products, but they lead to a lower market equilibrium than would be optimal if all information about the trustworthiness of buyers/sellers and the quality of the products offered were available at zero or lower costs.

Taking into account the aggregated level of transaction costs that would have to be added to the actual price for which a product is bought or sold, this perspective allows a better understanding of why the market volume for second-hand products is still small compared to virgin products. The data on sustainability attitudes of buyers as well as sellers of second-hand products also lead to the hypotheses that a large share of the market volume is due to actors with a higher intrinsic motivation, which could compensate these additional transaction costs to a certain extent.

The analysis allows for drawing conclusions on specific policy instruments in this context. Taking into account the level of transaction costs linked to purchasing or selling second-hand products, policies to support reuse should aim to decrease the necessary time and efforts to gather, evaluate, and monitor information, e.g., concerning the quality of products. Standardized regulations, i.e., regarding warranties or return options, could significantly increase incentives to consider second-hand as a viable alternative for new products. Considering that 66% of interviewees who already bought a used product during the last twelve months indicated their willingness to engage in additional second-hand transactions, it could be an option to subsidize the first purchase of a second-hand product, e.g., by providing vouchers. Similar incentives schemes for repair services have proven to be very effective (Stadt Wien 2021) because consumers gain insights on how to use relevant channels, and because the thresholds are lowered, transaction costs are reduced.

The results presented here are of course limited and preliminary as they are based on national data for Germany alone; as discussed above, even regional differences might be of significant relevance and results may differ in countries with more established reuse structures. In addition, the data are based on an online survey, the perception of transaction costs and barriers might thus be biased and subjective. Future research should therefore focus on more standardized empirical approaches to measuring transaction costs as a basis for assessing the economics of waste prevention, e.g., by taking into account the time required, the number of decisions to be made, and the number of stakeholders to be involved. The current lack of comparable data on the efficiency of waste prevention matters is also reflected in waste prevention policies, which rarely use market-based instruments, inter alia due to uncertainties about the relevance of transaction costs and thus about the actual effects of supporting second-hand products by reducing VAT rates (Wilts 2015), for example. The conceptional approach developed here for understanding second-hand markets could be a starting point for such a much more comprehensive analysis of the effectiveness and efficiency of waste prevention policies.

**Author Contributions:** H.W. was responsible for the conceptualization, methodology, and original draft preparation. Data curation was organized by M.F. and review and editing completed by C.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the German Federal Ministry of Research and Education within the context of the project "PUR–RESOURCE EFFICIENT PACKAGING WASTE PREVENTION".

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to confidentiality issues.

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

#### **References**

Coase, Ronald. 1998. The New Institutional Economics. *American Economic Reviw* 88: 72–74.


*2.2. Mouse Leydig Cells Proliferation Activity of Ten Fractions*

The proliferation activity of these 10 fractions was assessed using the MTT assay in TM3. All the 10 fractions were found to possess the proliferation activity (Figure 4).

**Figure 4.** Effects of the ten fractions on TM3 (a *p* < 0.01, b *p* < 0.05).

#### *2.3. Screening of Active Compounds by Using Partial Least Squares*

The selected initial data was further processed by PLS in order to establish a model for predicting the potential active components in *L. meyenii*. Parameters were set as follows: Confidence level was 95%, R2 = (0.0, 0.794), Q2 = (0.0, –0.285), and the parameters showed that the established PLS model was effective. We could use the PLS to carry on the weights analysis about the impact of the common peeks area exported from ten HPLC spectra of 10 fractions (x-axis) to the proliferative activity of TM3 (y-axis) and screening of major compounds which influenced bioactivity.

In our data set, the weights plot summarized the variables both to explain X and to correlate to Y. The results were shown in (Figure 5). The weights greater than one indicated important variables, and three potential biological markers of *N*-benzyl-hexadecanamide (**9**), *N*-benzyl-(9z,12z)-octadecadienamide (**6**) and *N*-benzyl-(9z,12z,15z)-octadecatrienamide (**2**) had high contributions to the proliferation activity of TM3. Meanwhile, they were considered to be potential active compounds for further study [19].

**Figure 5.** Model effect weights of the ten compounds on TM3.