**2. Overview of the concept of leadership in the health care sector**

In the health care sector, the term 'leadership' is closely associated, and often used interchangeably, with 'management'. Thus, this section presents an overview of the concept of leadership in the health care sector, drawing upon both management and leadership as both terms are seen as being relevant to health care services.

In a general sense, management entails planning, organising, control, budgeting, implementation, and evaluation; it ensures efficient utilisation of resources to achieve organisational goals [24]. The concept of management has been described as 'unique' in the sense that it has no universal application but rather is dictated by context, that is the policies, structures, and cultural values in which it is practised [25]. There are different schools of thought in management; one such school is the 'traditional' or bureaucratic (scientific) approach to management which emphasises a clear management structure, based on hierarchical chains of command involving workers' control and accountability for performance [26]. A competing school is the human relations approach to management which focuses on involvement of workers in the design of their work (participation, self-governance), motivating workers, satisfying their needs, promoting quality of life at work and managing conflict [27]. Numerous other theories of general management have followed, including institutional theory, open system and resource dependence theories, strategic management perspective, and organisational ecology [27]. These theories are beyond the scope of this chapter. Leadership, on the other hand, revolves around vision, ideas, direction, and inspiration; it establishes direction [28, 29] and motivates others [30, 31] to achieve organisational goals rather than a focus on day-to-day implementation of those goals [24]. According to (Bennis and Nanus [32] p. 21), "managers are people who do things right and leaders are people who do the right thing. The difference may be summarised as activities of vision and judgment (effectiveness) versus activities of mastering routines (efficiency)". Regardless of the differences between management and leadership in terms of roles and functions, both are recognised as important to the attainment of organisational goals and objectives [24].

policies, and advancement in medical and information technologies, also exert profound influences on the health sector [7–9]. Thus, the health care sector undergoes constant reforms arising from the interplay of factors both within and outside its control. Such reforms are necessary to meet the expectations of the population and ensure the delivery of safe, effec-

Effective leadership has been recognised as crucial in shaping organisational culture and driving the implementation of reforms in health care sector. This is evident in the growing interests in the concepts of health management and leadership, especially since the turn of the century, as reflected in the prevalence of studies on health management and leadership across different countries. Countries include Australia [3, 10, 11], Canada [12, 13], Ireland [14], Latin America [15], New Zealand [16], South Africa [17–19], and the United States of America [20–23]. Current interests in health management and leadership are, however, geared towards identification and assessment of essential competencies (that is knowledge, skills, and attitudes) required by health managers and leaders for effective performance in roles. Identification of such competencies is central to initiating appropriate training or professional development to

The purpose of this chapter is to examine the concept of 'leadership' in relation to the health care sector. This is achieved through a review of key studies on health management and leadership to provide contextual understanding of the concept and identify key areas of focus by health care organisations and researchers related to leadership in the health care sector.

In the health care sector, the term 'leadership' is closely associated, and often used interchangeably, with 'management'. Thus, this section presents an overview of the concept of leadership in the health care sector, drawing upon both management and leadership as both

In a general sense, management entails planning, organising, control, budgeting, implementation, and evaluation; it ensures efficient utilisation of resources to achieve organisational goals [24]. The concept of management has been described as 'unique' in the sense that it has no universal application but rather is dictated by context, that is the policies, structures, and cultural values in which it is practised [25]. There are different schools of thought in management; one such school is the 'traditional' or bureaucratic (scientific) approach to management which emphasises a clear management structure, based on hierarchical chains of command involving workers' control and accountability for performance [26]. A competing school is the human relations approach to management which focuses on involvement of workers in the design of their work (participation, self-governance), motivating workers, satisfying their needs, promoting quality of life at work and managing conflict [27]. Numerous other theories of general management have followed, including institutional theory, open system and resource dependence theories, strategic management perspective, and organisational ecology [27]. These theories are beyond the scope of this chapter. Leadership, on the other hand, revolves

enhance individual competence and improve organisational performance [21].

**2. Overview of the concept of leadership in the health care sector**

terms are seen as being relevant to health care services.

tive, and high quality-health care.

84 Leadership

Although management and leadership may represent two distinct disciplinary and practice areas, distinguishing between the two concepts in practice may be difficult [24]. In certain instances, management functions can provide leadership while leadership activities can contribute to managing [24]. Additionally, managers and leaders are expected to function effectively in different situations, not limited by their traditional roles, reflecting the view that they (managers and leaders) are expected to be all things to all people [33]. This view is consistent with that of Bass and Avolio [34] who opined that effective leadership is a reflection of an optimal mix of different styles, including management and leadership practices. Furthermore, the concept of 'distributed leadership' [35], which suggests one does not need to have a formal position of managerial authority to be a 'leader', further renders the debates on management/ leadership dichotomy as less important. Thus, while the distinction between management and leadership arises from the differences in roles and functions, the reality is that a role is often unconsciously chosen and not outlined explicitly in the organisation [36]. A role appears and changes as a result of gaps that need to be filled in the managerial jobs.

Arising from changes in the social context of health care, the dichotomy between management and leadership in the sector is increasingly narrowing [37]. Thus, managers (generalist trained managers, professional health service managers) fill management roles, perform management functions and provide leadership. On the other hand, clinicians (including doctors and nurses) and other professionals with no background in management may move into management roles and provide leadership. One change which has significantly affected the social context of health care is the increasing involvement of clinicians in the planning, management, and organisation of care in line with the concept of clinical leadership. Clinical leadership is provided by clinicians in clinical settings to ensure safe, effective, and high-quality care [38, 39]. Such roles are usually performed in collaboration with non-clinical management or leadership roles and functions. Thus, in the health care sector, a 'managerialism' model, dominated by generalist trained managers, is being replaced by a unified (collective) leadership structure for the effective running of health care services. Such an approach to management is somewhat similar to the concept of 'distributed' or 'shared' leadership (see below), where different actors engage in tasks that are 'stretched' or distributed across the organisation [40].

There are many leadership theories which underlie management and leadership practices; prominent among them is contingency theory. Contingency (or situational) theory emerged in the early 1960s due to inability of previous theories to explain different aspects of leader behaviour [36]. Contingency theory is based on the premise that the behaviour exhibited by a leader varies, depending on the prevailing circumstance or situation [41–44]. According to Smirich and Morgan [45], leadership is a product of interaction between the situation, the leader, and the followers. Other theories which have their roots in contingency theory include transactional and transformational leadership theories, which were introduced by Burns in 1978 [36]. Transactional leaders are associated with contingency rewards (exchange of rewards for compliance) and management by exception (either actively or passively) [27, 36]; they emphasise legitimate power and respect for rules and tradition [46]. In view of the practices associated with transactional leadership, some authors have connected this leadership style with management functions [42, 43, 47, 48]. In contrast, transformational leadership motivates and inspires followers to rise above their personal interest for the sake of the organisation; it empowers employees to participate in the process of transforming the organisation and initiate major changes and reforms [27, 34]. One important outcome of transformational leadership is 'empowerment', which entails sharing of leadership process between the leader and the followers [34, 42]. This feature is consistent with the original idea of Burns that leadership may be exhibited by anyone in the organisation in any type of position [42].

specific needs of each manager in line with his or her dominant management or leadership role [5]. Thus, in addition to identifying core competencies, it may also be useful to identify specific competencies required by certain individuals or members of a professional body for

The Concept of Leadership in the Health Care Sector http://dx.doi.org/10.5772/intechopen.76133 87

Competence is the ability to consistently produce the outcomes (of behaviour) required for effective achievement of organisational goals [57]. In other words, a competent health manager or leader possesses the requisite knowledge, skills and attitudes that enable him or her to manage or lead effectively. The term 'proficiency', or 'competence level', refers to the level of expertise for a particular competency. A 'competency model' is a framework which contains competency statements in which essential knowledge, skills and attitudes desirable for specific roles are described [57], or a collection of competencies required for successful performance [58]. A 'competence model', on the other hand, refers to a framework which describes

Other terms commonly associated with competency are 'capability' and 'capacity'. Capability refers to the process which allows individuals to demonstrate or express the required competencies on their jobs; it is the ease with which the required competencies can be accessed, deployed, or applied by individuals [59]. Capacity, on the other hand, refers to the power or ability of individuals to hold or possess the required competencies at a level considered suf-

As pointed out earlier, several studies have been conducted on health management and leadership. The majority of these focused on identification and/or assessment of essential competencies required by health managers and leaders for effective performance in management and leadership roles. The focus on competencies has been informed by the need to develop strong and competent health management and leadership workforces, given the pivotal roles of leaders from health management and clinical backgrounds in driving changes and leading development in health care organisations. This much has also been recognised by the World Health Organisation, which has advocated the need to strengthen management and leadership capabilities at all levels of the health system [60, 61]. Different approaches are being used to identify and assess essential competencies required by health management and leadership workforces. These approaches include literature review, position description analysis, the Delphi technique, surveys, interview of job incumbents and focus groups. The optimal approach recommended for identification and assessment of competencies involves the use

A major point of contention in health management and leadership is whether competencies are similar across countries and organisational contexts, or are contextually sensitive. While some authors have argued that certain 'core' competencies are applicable to most health contexts [5, 11], others have advocated for more contextually compatible competencies based on the premise that competencies may be influenced by contextual factors such as demographic characteristics of personnel, as well as the size, culture and needs of organisations [12, 22, 63, 64]. Notwithstanding the argument, certain domains of competencies have been identified across several studies as important for health management and leadership roles, regardless of the contexts in which those roles are performed. These domains include communication, interpersonal

of multiple methods to improve the credibility of findings [54, 62].

the process and work outputs required to achieve the set goals of specific roles [57].

effective performance [5].

ficient for a role [59].

Closely related to the notion of 'shared leadership' is a concept known as 'distributed leadership'. As stated earlier, distributed leadership focuses on how actors engage in tasks that are 'stretched' or distributed across the organisation [35]; it sees leadership activities as a situated and social process at the intersection of leaders, followers, and the situation [49]. In practice, leaders from both health management and clinical backgrounds are expected to demonstrate leadership theories as they (the theories) underlie the basis of the knowledge, skills, and attitudes (that is competencies, see below) required by the health management and leadership workforces for successful performance in roles.


**2.1. Flexible fluidic actuators**

A Flexible Fluidic Actuator generally consists of a flexible shell that transmits potential energy, delivered by the pressurized fluid, into a mechanical force, which then can be used to create a motion.

The flexible fluidic operating principle has a strong background in biomimetics. Gutmann [41, 42] established the "Hydroskelett-Theorie" as an approach to explain evolutionary biology via the concepts of constructional morphology. He understood that the design-principles of hydrosceletts are responsible for the general designs of organisms. Gudo et al. [39, 40] developed this idea further by introducing the term "Engineering Morphology which describes how Gutmann's ideas can be applied to technical design. The biomimetic background of flexible fluidic actuation was specifically discussed in [11, 130]. These works discuss several examples on weevils and spiders and describe how crucial the membrane properties are regarding efficiency and durability of the whole actuation system. The transfer of the evolutionary optimized flexible fluidic drives developed by nature into powerful technical systems is one focus of this work.

A useful classification of Flexible Fluidic Actuators can be made according to their operating principle, or the kind of force they are creating. Here we differentiate between designs that use expansion, contraction or bending directions to drive a system.


**2.3. On-line SPE**

To meet the ever-growing demands for sensitivity, reliability and speed, the continuous development of more efficient methods for both sample pretreatment and analysis is crucial.

Current Trends in Sample Treatment Techniques for Environmental and Food Analysis 137

**Figure 2.** Typical setup of an on-line SPE-LC system with a 2-position 6-port switching valve; (a) Load

Recent advances in technology have made the Ultra High Performance Liquid Chromatography (UHPLC)/mass spectrometry (MS) system a perfect candidate for combination with on-line SPE. The on-line SPE-UHPLC/MS allows complete separation of

Gosetti et al. [5], applied an automated on-line SPE UHPLC–MS/MS method for the identification and quantification of nine perfluorinated compounds (PFCs) in matrices of environmental, biological and food interest. The SPE protocol was performed by using an anion exchange SPE column (Poros HQ column). The separation of nine PFCs was obtained within 7 min. The limits of detection (LODs) ranged from 3 to 15 ng L−1 whereas the limits of

The same authors performed a simultaneous determination of thirteen polycyclic aromatic hydrocarbons (PAHs) and twelve aldehydes in cooked food by means of an automated online SPE-UHPLC-MS. The resolution allowed the separation of four couples of PAH isomers. SPE treatment was made using Strata C18-E column and the extraction procedure was carefully optimized in order to apply the whole methodology to the analysis of different food matrices as salmon, frankfurter, steak, and pork chop, subjected to different cooking modes (smoked, grilled, cooked in oil or in butter). LODs values ranging from 0.028 to 0.768 µg L−1 for PAHs and from 0.002 to 0.125 µg L−1 for aldehydes were obtained [4].

Previously, PAH, such as naphthalene, biphenyl, acenaphthene, anthracene and pyrene have been determined in natural water by using on-line SPE–HPLC-UV [47]. Fluorocarbon polymer SPE sorbent was used. This application resulted in better extraction selectivity towards PAHs in comparison with several other sorbents and provided no additional peak broadening. Detection limits of method were established as 5 ng L−1 (biphenyl), 7 ng L−1

(anthracene), 8 ng L−1 (acenaphthene), 30 ng L−1 (pyrene), 40 ng L−1 (naphthalene).

high number of analytes via a single chromatographic run that takes few minutes.

position and (b) injection position

quantification (LOQs) from 10 to 50 ng L−1.

SPE technique can be easily coupled on-line to high performance liquid chromatography (HPLC) and gaschromatography (GC) systems. On-line systems are beneficial when the amount of sample is limited, or when very high sensitivity is required. In most cases, even though the use of an automated on-line instrument is quite straightforward, experienced personnel are required for method development and eventual trouble-shooting.

The strong differences among the solid phase extraction principle and the gas chromatography analysis made the on-line combination of SPE and GC more complicated.

Nevertheless, the combination with GC has already been successfully applied in environmental analysis [44-46]. In the on-line SPE-GC the analytes are trapped in a short column (10-20 mm×1-4.6 mm i.d.) packed with a suitable stationary phase (typically C8, C18 or styrene-divinylbenzene copolymer). The SPE procedures are essentially the same as the off-line ones. It involves conditioning of the SPE material before loading of the sample. Since water is not a good solvent for GC, primarily because it hydrolyses the siloxane bonds in GC columns causing deterioration of the column performance, the introduction of water directly to GC should be avoided. After trapping, and before elution of the analytes, the SPE column is often dried with a gas flow, or the extract is dried with a separate drying column packed with copper sulphate or silica to remove water, which is placed after the SPE column. The column can also be heated during the drying process, but this increases the risk of losing volatile analytes. The elution of the analytes is performed with a solvent suitable for the GC injector system.

On the other hand, the methods which combine SPE with HPLC are the most frequently used in environmental and food analysis, mainly to determine polar compounds in water solution. Different systems and configurations are available. The most commonly used approach involves the implementation of a small SPE column within the injection loop of a six-port rotary valve (**Figure 2**).

After conditioning, sample application, and eventual clean-up by means of a high-pressure pump, the SPE column is placed in front of an analytical column by switching the valve into the "inject" position. A sample is thus loaded in this SPE column, whereupon the valve is switched in order to elute the analytes out of the sorbent by the LC mobile phase and transfer them into the analytical column [3]. The SPE column is reusable. However, the reusability can cause a progressive deterioration of the column material and thus, lead to a change in their selectivity and capacity. Moreover, the SPE column must be filled with a sorbent compatible with the sorbent of the analytical column which efficiently traps the analytes. The SPE column should be as small as possible in order to prevent band broadening. Usually, the dimension of stainless steel columns is 30 mm length, 2 mm i.d. and 8 mm length, 3 mm i.d.

To meet the ever-growing demands for sensitivity, reliability and speed, the continuous development of more efficient methods for both sample pretreatment and analysis is crucial. SPE technique can be easily coupled on-line to high performance liquid chromatography (HPLC) and gaschromatography (GC) systems. On-line systems are beneficial when the amount of sample is limited, or when very high sensitivity is required. In most cases, even though the use of an automated on-line instrument is quite straightforward, experienced

The strong differences among the solid phase extraction principle and the gas chromatography analysis made the on-line combination of SPE and GC more complicated.

Nevertheless, the combination with GC has already been successfully applied in environmental analysis [44-46]. In the on-line SPE-GC the analytes are trapped in a short column (10-20 mm×1-4.6 mm i.d.) packed with a suitable stationary phase (typically C8, C18 or styrene-divinylbenzene copolymer). The SPE procedures are essentially the same as the off-line ones. It involves conditioning of the SPE material before loading of the sample. Since water is not a good solvent for GC, primarily because it hydrolyses the siloxane bonds in GC columns causing deterioration of the column performance, the introduction of water directly to GC should be avoided. After trapping, and before elution of the analytes, the SPE column is often dried with a gas flow, or the extract is dried with a separate drying column packed with copper sulphate or silica to remove water, which is placed after the SPE column. The column can also be heated during the drying process, but this increases the risk of losing volatile analytes. The elution of the analytes is performed with a solvent suitable for the GC

On the other hand, the methods which combine SPE with HPLC are the most frequently used in environmental and food analysis, mainly to determine polar compounds in water solution. Different systems and configurations are available. The most commonly used approach involves the implementation of a small SPE column within the injection loop of a

After conditioning, sample application, and eventual clean-up by means of a high-pressure pump, the SPE column is placed in front of an analytical column by switching the valve into the "inject" position. A sample is thus loaded in this SPE column, whereupon the valve is switched in order to elute the analytes out of the sorbent by the LC mobile phase and transfer them into the analytical column [3]. The SPE column is reusable. However, the reusability can cause a progressive deterioration of the column material and thus, lead to a change in their selectivity and capacity. Moreover, the SPE column must be filled with a sorbent compatible with the sorbent of the analytical column which efficiently traps the analytes. The SPE column should be as small as possible in order to prevent band broadening. Usually, the dimension of stainless steel columns is 30 mm length, 2 mm i.d.

personnel are required for method development and eventual trouble-shooting.

**2.3. On-line SPE**

injector system.

six-port rotary valve (**Figure 2**).

and 8 mm length, 3 mm i.d.

**Figure 2.** Typical setup of an on-line SPE-LC system with a 2-position 6-port switching valve; (a) Load position and (b) injection position

Recent advances in technology have made the Ultra High Performance Liquid Chromatography (UHPLC)/mass spectrometry (MS) system a perfect candidate for combination with on-line SPE. The on-line SPE-UHPLC/MS allows complete separation of high number of analytes via a single chromatographic run that takes few minutes.

Gosetti et al. [5], applied an automated on-line SPE UHPLC–MS/MS method for the identification and quantification of nine perfluorinated compounds (PFCs) in matrices of environmental, biological and food interest. The SPE protocol was performed by using an anion exchange SPE column (Poros HQ column). The separation of nine PFCs was obtained within 7 min. The limits of detection (LODs) ranged from 3 to 15 ng L−1 whereas the limits of quantification (LOQs) from 10 to 50 ng L−1.

The same authors performed a simultaneous determination of thirteen polycyclic aromatic hydrocarbons (PAHs) and twelve aldehydes in cooked food by means of an automated online SPE-UHPLC-MS. The resolution allowed the separation of four couples of PAH isomers. SPE treatment was made using Strata C18-E column and the extraction procedure was carefully optimized in order to apply the whole methodology to the analysis of different food matrices as salmon, frankfurter, steak, and pork chop, subjected to different cooking modes (smoked, grilled, cooked in oil or in butter). LODs values ranging from 0.028 to 0.768 µg L−1 for PAHs and from 0.002 to 0.125 µg L−1 for aldehydes were obtained [4].

Previously, PAH, such as naphthalene, biphenyl, acenaphthene, anthracene and pyrene have been determined in natural water by using on-line SPE–HPLC-UV [47]. Fluorocarbon polymer SPE sorbent was used. This application resulted in better extraction selectivity towards PAHs in comparison with several other sorbents and provided no additional peak broadening. Detection limits of method were established as 5 ng L−1 (biphenyl), 7 ng L−1 (anthracene), 8 ng L−1 (acenaphthene), 30 ng L−1 (pyrene), 40 ng L−1 (naphthalene).

Gallart-Ayala et al. [48], used an automated on-line SPE fast LC–MS/MS method for the simultaneous analysis of bisphenol A (BPA), bisphenol F (BPF), bisphenol E (BPE), bisphenol B (BPB) and bisphenol S (BPS) in canned soft drinks without any previous sample treatment. SPE on-line pre-concentration was performed by using a C18 cartridge. The analysis of all compounds was accomplished in 3 min. Quality parameters of the method were established and the authors obtained a simple, fast, reproducible (RSD values lower than 10%) and accurate (trueness higher than 93%) method for the analysis of bisphenols in canned soft drinks at the ng L−1 level using matrix-matched calibration.

Current Trends in Sample Treatment Techniques for Environmental and Food Analysis 139

**Figure 3.** Schematic representation of non-covalent molecular imprinting procedures: (1) complex formation between the template (methacrylic acid) and the functional monomers (estriol), (2)

Out of all the MIPs applications, the use of MIPs as selective sorbents for solid-phase extraction (MIP-SPE) represents the most important application area in the field of analytical separation sciences [54]. Solid-phase extraction (SPE) is a well-established method routinely used for clean-up and pre-concentration of analytes in a wide range of environmental, pharmaceutical, agricultural and food analysis [1]. Nevertheless, sorbents used in conventional SPE often lack selectivity resulting in co-extraction of interfering matrix components. Therefore, specificity, selectivity and sensitivity together with high extraction efficiency can be obtained using sorbents based on molecularly imprinted polymers

To assess the potential of MIPs in terms of selectivity, we have compared the ability of MIP-SPE for selective extraction of zearalenone from cereal sample extracts with that of a commercial immunoaffinity column (IAC). **Figure 4** shows the similarity of the behavior of these two types of selective sorbents, resulted in high degrees of clean-up. In both cases, very reliable baselines and similar recoveries were obtained, proving that the high selectivity of immunoaffinity sorbents also can be achieved with molecularly imprinted polymers SPE. Furthermore, previous studies have found MIP-SPE to have a similar

selectivity but a higher capacity than commercial IAC columns [49,55].

polymerization, (3) template extraction, (4) analyte rebinding.

**3.1. Applications of MIPs to SPE**

(MIPs) [8].

Finally, in the current year, Vega-Morales et al. [2] used an on-line SPE-UHPLC-MS/MS to characterize 27 endocrine disrupting compounds (norethindrone, norgestrel, 17-alphaethinyloestradiol, etc.) in sewage samples. SPE treatment was performed by using Oasis HLB columns (mixed-mode sorbent). The complete analysis of each sample required less than 4 min and provided satisfactory recoveries (72–110%) and limits of detection in the order of few nanograms per liter (0.3-2.1 ng L−1).


**Meet the editor**

Dr. Alexander Banishev is a research associate at the University of Illinois, Urbana-Champaign (UIUC) (USA). He received his PhD degree in Physics at Lomonosov Moscow State University (Russia) in 2008. Before joining the University of Illinois, he was working at the University of California, Riverside. His primary research interests include optical and laser physics, light interaction with nano- and molecular materials, and optical properties of materials under extreme conditions and precise measurements. He reviews articles for *Optical Society of America* journals.

Dr. Mithun Bhowmick completed his PhD degree in Physics from Virginia Tech in 2012 and currently is working as a research associate at the University of Illinois, Urbana-Champaign (UIUC). Before Joining the UIUC, he worked at Nazarbayev University and National Autonomous University of Mexico as full-time and visiting professors, respectively. His research interests are optical properties of semiconductors, many body effects in scattering mechanisms of carriers/spins, and energetic liquids under extreme conditions. He is a recipient of Jamie Dunn Award, Philip Morris Fellowship, and Ministry of Education and Science grant from the Republic of Kazakhstan for his studies on semiconductor heterostructures. He is a member of American Physical Society and Optical Society of America and reviews articles for international journals on materials science/applied physics (*Physical Review B*, *Journal of Applied Physics*, etc.).

Dr. Jue Wang is a research associate at the University of Illinois, Urbana-Champaign, USA. He received his PhD degree in Geosciences at Princeton University in 2014. Before joining the University of Illinois, he was studying equation of state and structure of materials at high pressures and high temperatures at Princeton University. His research interests include physical and chemical properties of materials at extreme conditions. He reviews articles for *Scientific Reports* and *Optics Letters*.


**6. Boom aerodynamics**

MEDA wind sensors are a new design based on the wind REMS sensor [2, 3] that was embarked on the Mars Science Laboratory (MSL) Curiosity rover [4] currently sending data from Mars atmosphere. The behavior of thermal wind sensors installed over the boom of the Mars rover is similar to hot wire, described in earlier paragraph. They are based on a group of four sensitive surface hot film sensors (named dices A, B, C, and D) installed in the same plane (see **Figure 2**). Sensors are

refrigerated when the wind is blowing over each dice, and consequently, an electric power must be apply to keep temperature constant on the dice (constant operation reference temperature CTA). The value of electric power gives a measurement of the airspeed on each dice and the direction from blowing. Dices situated in front the flow are cooled more than those located in back positions, since the wind heats up as the first ones are cooled and heat is transferred to the airstream. A comparative analysis of the electric power required for each of the four dices will give us an

Finally, a joint calibration of the four dices allows us to know the wind speed and

**Figure 3** shows the set-up for functional tests of rover wind sensors. A simplified version of hot film sensor, similar to the real sensor was implemented over a flat plate. A specially designed bed fabrication in extruded polystyrene was used to support the plate with hot film sensors in order to perform the functional tests by wind tunnel testing to verify the wind endurance. During this test campaign, several values of airspeed were blown by wind tunnel and the air was flowing on the sensors refrigerating them. Readings of electric signals from dices electronic chip were acquired to verify the correct behavior of the wind sensors, and its integrity was verified when the flow was blowing over them. A laser Doppler anemometer

the incidence angle over the sensor. A more detailed description is in Ref. [4].

indication of the angle of incidence of the air flow.

was used as an airspeed standard.

*Mars Exploration - A Step Forward*

**Figure 2.**

**Figure 3.**

**74**

*Mars rover wind sensors during functional tests.*

*Rover wind sensor boom.*

The rover wind sensors are installed on the boom surface. Booms are located in the vertical mast over the upper rover central box surface (see **Figures 1** and **2**). Two booms are at the same height and contained in the same horizontal plane, with an angular offset of 120°. The boom external geometry is similar to these of the Pitot-static tube. This is a classical instrument for measuring airspeed in aerodynamics and fluid mechanics that has proven its efficiency for more than a century. This tube has a hemispherical head followed by a cylindrical body with axisymmetric geometry so that the longitudinal flow is coming to the wind sensor without detachment. On the other hand, rover booms have a hemispherical head followed by a cylindrical body with polygonal faces where thermal sensors are installed (see **Figure 2**). In this section, a theoretical analysis of two simplified cases is presented: longitudinal axisymmetric flow and cross flow over the boom.

### **6.1 Longitudinal axisymmetric flow**

When the wind is blowing in longitudinal axisymmetric direction, the head of the boom receives the flow without detachment. A first approximation to this kind of flow can be studied by considering the incompressible potential flow on the axisymmetric Rankine half-body of revolution. This flow is produced when a uniform stream of velocity *U*∞ is flowing over a three-dimensional point source of strength *M* located at the origin. This situation is depicted in **Figure 4**, for a half-body of revolution with radius *a*.

A stagnation point denoted by P is produced by the upstream source point when both singularities are equal in velocity. The location of this point is calculated as follows:

$$U\_{\infty} = \frac{M}{4\pi d^2},\tag{14}$$

and finally, the distance to point P is

$$d = \frac{1}{2} \sqrt{\frac{M}{\pi U\_{\infty}}}.\tag{15}$$

The velocity potential *Φ* corresponding to the superposition of a uniform stream and a source located in the origin is given by the following expression:

$$\Phi(\mathbf{x}, \mathbf{r}) = U\_{\infty}\mathbf{x} - \frac{M}{4\pi R} \tag{16}$$

where *R* ¼ ffiffiffiffiffiffiffiffiffiffiffiffiffiffi *x*2 þ *r*2 p .

**Figure 4.** *Axial flow over wind sensor boom.*

On the other hand, the Stokes stream function *Ψ* for this flow is given by,

$$
\Psi^{\Psi}(r,z) = \frac{M}{2} \left( 1 - \frac{\varkappa}{R} \right) + \pi r^2 U\_{\infty}. \tag{17}
$$

*u x*ð Þ ,*r U*∞

*Aerodynamics of Mars 2020 Rover Wind Sensors DOI: http://dx.doi.org/10.5772/intechopen.90912*

> *u x*ð Þ ,*r U*∞

¼ 1 þ

**Figure 5** shows the graph of nondimensional velocity *u/U*∞ versus the nondimensional distance *x/2a*. The velocity is growing from the stagnation point located at *χP* ¼ �1*=*4 until unity nondimensional velocity that is reached when curve cross the origin (*χ* ¼ 0). After that, a peak is produced, and the freestream velocity value is got for a longitudinal distance *x/2a = 1.5. S*o that, when the flow is coming to a boom section located at a distance of approximately equal to three times the radius (*x = 3a*), the wind flows with the freestream velocity, and the hot film sensor will be refrigerated by the same manner as in nonperturbed conditions.

Wind flowing transversal to the boom (boom in cross-flow) can be studied as a first approximation by the two-dimensional complex potential flow over a circular

variable, *ζ*, as follows:

**6.2 Transversal flow**

**Figure 5.**

**Figure 6.**

**77**

*Potential flow of a cylinder.*

cylinder, as represented in **Figure 6**.

*Nondimensional wind velocity on rover boom in axial flow.*

¼ 1 þ

1 16

And simplifying, we can find an expression that only depends on the unique

*χ* ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

8*ζ*2 � 1 � � ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi

1 � 4*ζ*2 q� �

*χ*2 þ *ζ*2 � �3 q *:* (27)

64 *:* (28)

The half-body surface stream function is equal to the flow rate coming from the inner of the half-body. Taking into account that it is a body of revolution, transversal area is *A* ¼ *πa*2 and the flow coming from the inner body, crossing the circular area denoted as *A* (see **Figure 4**), is *AU*∞, exactly the strength of the point source (*M* ¼ *πa*2*U*∞), and the distance *d* is computed being *d = a/2.*

The dividing streamline represents the surface body, and it is obtained when the stream function is equal to the source strength, *M*,

$$M = \frac{M}{2} \left( 1 - \frac{\varkappa}{R} \right) + \pi r^2 U\_{\infty}. \tag{18}$$

And the corresponding velocity is

$$u(\mathbf{x}, r) = \frac{\partial \Phi(\mathbf{x}, r)}{\partial \mathbf{x}} = U\_{\infty} + \frac{M}{4\pi} \frac{\mathbf{x}}{\left(\mathbf{x}^2 + r^2\right)^{3/2}} \tag{19}$$

$$w(\mathbf{x}, r) = \frac{\partial \Phi(\mathbf{x}, r)}{\partial r} = \frac{M}{4\pi} \frac{r}{(\mathbf{x}^2 + r^2)^{3/2}}. \tag{20}$$

Velocity over body surface is computed taking into account that both variables *x* and *r* are related by the body stream function as follows:

$$\frac{M}{2}\left(1+\frac{\varkappa}{R}\right) = \pi r^2 U\_{\infty} \tag{21}$$

Resulting in

$$r^2 = \frac{a^2}{2} \left( 1 + \frac{x}{\sqrt{x^2 + r^2}} \right) \tag{22}$$

Taking nondimensional variables defined as

$$\chi = \frac{\mathfrak{x}}{2a} \tag{23}$$

$$
\zeta = \frac{r}{2a}.\tag{24}
$$

Both variables are related by the stream function as follows:

$$8\zeta^2 = 1 + \frac{\chi}{\sqrt{\chi^2 + \zeta^2}}.\tag{25}$$

The variable *χ* results in a function of *ζ*, given by,

$$\chi^2 = \frac{\left(8\zeta^2 - 1\right)^2}{16\left(1 - 4\zeta^2\right)}.\tag{26}$$

Finally, the longitudinal velocity component is given by the following expression:

*Aerodynamics of Mars 2020 Rover Wind Sensors DOI: http://dx.doi.org/10.5772/intechopen.90912*

$$\frac{u(\varkappa,r)}{U\_{\infty}} = 1 + \frac{1}{16} \frac{\varkappa}{\sqrt{\left(\varkappa^2 + \zeta^2\right)^3}} \cdot \tag{27}$$

And simplifying, we can find an expression that only depends on the unique variable, *ζ*, as follows:

$$\frac{u(\varkappa,r)}{U\_{\infty}} = 1 + \frac{(8\zeta^2 - 1)\sqrt{\left(1 - 4\zeta^2\right)}}{64}.\tag{28}$$

**Figure 5** shows the graph of nondimensional velocity *u/U*∞ versus the nondimensional distance *x/2a*. The velocity is growing from the stagnation point located at *χP* ¼ �1*=*4 until unity nondimensional velocity that is reached when curve cross the origin (*χ* ¼ 0). After that, a peak is produced, and the freestream velocity value is got for a longitudinal distance *x/2a = 1.5. S*o that, when the flow is coming to a boom section located at a distance of approximately equal to three times the radius (*x = 3a*), the wind flows with the freestream velocity, and the hot film sensor will be refrigerated by the same manner as in nonperturbed conditions.

#### **6.2 Transversal flow**

On the other hand, the Stokes stream function *Ψ* for this flow is given by,

1 � *x R* � �

The half-body surface stream function is equal to the flow rate coming from the inner of the half-body. Taking into account that it is a body of revolution, transversal area is *A* ¼ *πa*2 and the flow coming from the inner body, crossing the circular area denoted as *A* (see **Figure 4**), is *AU*∞, exactly the strength of the point source

The dividing streamline represents the surface body, and it is obtained when the

þ *πr* 2

> *M* 4*π*

*x*

*r*

1 � *x R* � �

*∂x* ¼ *U*∞ þ

Velocity over body surface is computed taking into account that both variables *x*

¼ *πr* 2

*x* ffiffiffiffiffiffiffiffiffiffiffiffiffiffi *x*2 þ *r*2 p � �

∂Φð Þ *x*,*r ∂r* ¼ *M* 4*π*

1 þ *x R* � �

1 þ

*χ* ¼ *x* 2*a*

*ζ* ¼ *r* 2*a*

8*ζ*2 ¼ 1 þ *χ* ffiffiffiffiffiffiffiffiffiffiffiffiffiffi

*χ*2 ¼ 8*ζ*2 � 1 � �2

Finally, the longitudinal velocity component is given by the following

þ *πr* 2

*U*∞*:* (17)

*U*∞*:* (18)

*x*2 þ *r*2 ð Þ3*=*2 (19)

*x*2 þ *r*2 ð Þ3*=*2 *:* (20)

*U*∞ (21)

*:* (24)

*χ*2 þ *ζ*2 p *:* (25)

16 1 � 4*ζ*2 � � *:* (26)

(22)

(23)

*M* 2

*Ψ*ð Þ¼ *r*, *z*

(*M* ¼ *πa*2*U*∞), and the distance *d* is computed being *d = a/2.*

*M* ¼ *M* 2

∂Φð Þ *x*,*r*

stream function is equal to the source strength, *M*,

*u x*ð Þ¼ ,*r*

*w x*ð Þ¼ ,*r*

and *r* are related by the body stream function as follows:

*M* 2

*r* 2 ¼ *a*2 2

Both variables are related by the stream function as follows:

The variable *χ* results in a function of *ζ*, given by,

Taking nondimensional variables defined as

And the corresponding velocity is

*Mars Exploration - A Step Forward*

Resulting in

expression:

**76**

Wind flowing transversal to the boom (boom in cross-flow) can be studied as a first approximation by the two-dimensional complex potential flow over a circular cylinder, as represented in **Figure 6**.

**Figure 5.** *Nondimensional wind velocity on rover boom in axial flow.*

**Figure 6.** *Potential flow of a cylinder.*

The complex potential *w z*ð Þ corresponding to a cylinder with radius *a* is given by the superposition of a uniform stream and a doublet [12]

$$w(z) = U\_{\infty} \left( z + \frac{a^2}{z} \right) \tag{29}$$

where *z* is the complex variable defines as follows:

$$z = \varkappa + i\mathfrak{y}.\tag{30}$$

Real and imaginary parts of *w* define the potential of velocity *ϕ* and the stream function *ψ*, respectively,

$$\phi = U\_{\infty} \left( r + \frac{a^2}{r} \right) \cos \theta \tag{31}$$

$$
\psi = U\_{\infty} \left( r - \frac{a^2}{r} \right) \sin \theta. \tag{32}
$$

over the body wall needs zero velocity in the wall and the outer velocity (*U*∞) in the boundary layer limit. The boundary layer is a thin layer where the effects of viscous forces are of the same order of the inertial forces. The Reynolds number of flow outer boundary layer is larger than unity, and consequently, the inertial forces are larger than the viscous. When the wind is flowing on the boom surface, the boundary layer is growing downstream and the turbulence and adverse pressure gradients produce the separation of the boundary layer and the detachment of flow, as it can be observed in **Figure 8**. In this situation, wind is flowing over booms in very complex conditions to be simulated analytically and the flow coming to each side of boom depends on the incidence angle of wind, so that thermal sensors are operating in a no ideal condition and heat transfer mechanisms are far from a theoretical environment. It is because the booms are calibrated isolated in order to characterize the output electrical signals from sensor when they are subjected to different wind

*Real flow around a circular cylinder: Upstream cylinder (left) and behind the cylinder (right).*

*Aerodynamics of Mars 2020 Rover Wind Sensors DOI: http://dx.doi.org/10.5772/intechopen.90912*

The external surface of rover is not designed following aerodynamics criteria. The main body of this vehicle is a box with rectangular section, supported by six wheels. A vertical mast is erected on the upper surface of the main box body. The instruments of MEDA are installed over this mast. Two booms are located perpendicular to the axis mast. The rover vehicle is larger than other elements as mast and booms, and the flow viewed by small devices is mainly affected by the presence of

conditions.

**Figure 7.**

the rover.

**79**

**Figure 8.**

**7. Rover vehicle aerodynamics**

*Boundary layer over the boom.*

The conjugate velocity is obtained directly by derivation as follows:

$$\frac{dw}{dz} = U\_{\infty} \left( 1 - \frac{a^2}{z^2} \right) = u - iv. \tag{33}$$

This expression can be simplified by making use of the Euler formula *z*�2 ¼ *a*�2*e*�*i*2*θ* ¼ *a*�2ð Þ *cos* 2*θ* � *i sin* 2*θ* , and the velocity components over the cylinder surface are the followings:

$$u = 2U\_{\infty} \sin^{2}\theta \tag{34}$$

$$v = -2U\_{\infty} \sin \theta \cos \theta. \tag{35}$$

The square of velocity magnitude is given by

$$\left|V\right|^2 = \mathfrak{u}^2 + \mathfrak{v}^2\tag{36}$$

$$\left|V\right|^2 = U\_{\infty}^2 \left[ (\mathbf{1} - \cos 2\theta)^2 + (\sin 2\theta)^2 \right] \tag{37}$$

$$\left|V\right|^2 = 2U\_{\infty}^2(1 - \cos 2\theta). \tag{38}$$

And finally, the modulus of velocity over the cylinder surface is

$$|V| = 2\,\,U\_{\infty}\sin\theta.\tag{39}$$

When the angle is zero, the velocity is zero, corresponding to a stagnation point, but when angle is 90°, the velocity is 2 *U*∞, rising to the maximum value of velocity.

The potential flow approximation is valid only in face front the flow, but it is not valid in the wake because the flow is detached. **Figure 7** shows a comparison view between attached flow upstream cylinder (left) and detached flow behind the cylinder (right).

#### **6.3 Boundary layer**

Potential flow is used as a first estimation of flow parameters, but it is not a real flow because viscosity is not present in these flow models. The no-slip condition

*Aerodynamics of Mars 2020 Rover Wind Sensors DOI: http://dx.doi.org/10.5772/intechopen.90912*

The complex potential *w z*ð Þ corresponding to a cylinder with radius *a* is given by

Real and imaginary parts of *w* define the potential of velocity *ϕ* and the stream

*a*2 *r* � �

*r* � �

*z*2 � �

This expression can be simplified by making use of the Euler formula *z*�2 ¼ *a*�2*e*�*i*2*θ* ¼ *a*�2ð Þ *cos* 2*θ* � *i sin* 2*θ* , and the velocity components over the cylinder

*u* ¼ 2*U*∞ *sin* 2

∞ ð Þ 1 � *cos* 2*θ* 2 þ ð Þ *sin* 2*θ* 2 h i

When the angle is zero, the velocity is zero, corresponding to a stagnation point, but when angle is 90°, the velocity is 2 *U*∞, rising to the maximum value of velocity. The potential flow approximation is valid only in face front the flow, but it is not valid in the wake because the flow is detached. **Figure 7** shows a comparison view between attached flow upstream cylinder (left) and detached flow behind the

Potential flow is used as a first estimation of flow parameters, but it is not a real flow because viscosity is not present in these flow models. The no-slip condition

*ϕ* ¼ *U*∞ *r* þ

*ψ* ¼ *U*∞ *r* � *a*2

The conjugate velocity is obtained directly by derivation as follows:

*dz* ¼ *U*∞ 1 � *a*2

*a*2 *z* � �

*z* ¼ *x* þ *iy:* (30)

*cosθ* (31)

*sinθ:* (32)

¼ *u* � *iv:* (33)

*θ* (34)

*v* ¼ �2*U*∞*sinθcosθ:* (35)

j j *V* 2 ¼ *u*2 þ *v*2 (36)

j j *V* ¼ 2 *U*∞*sinθ:* (39)

∞ð Þ 1 � *cos* 2*θ :* (38)

(29)

(37)

*w z*ð Þ¼ *U*∞ *z* þ

the superposition of a uniform stream and a doublet [12]

where *z* is the complex variable defines as follows:

*dw*

The square of velocity magnitude is given by

j j *V* 2 ¼ *U*2

j j *V* 2 ¼ 2*U*2

And finally, the modulus of velocity over the cylinder surface is

function *ψ*, respectively,

*Mars Exploration - A Step Forward*

surface are the followings:

cylinder (right).

**78**

**6.3 Boundary layer**

**Figure 7.** *Real flow around a circular cylinder: Upstream cylinder (left) and behind the cylinder (right).*

over the body wall needs zero velocity in the wall and the outer velocity (*U*∞) in the boundary layer limit. The boundary layer is a thin layer where the effects of viscous forces are of the same order of the inertial forces. The Reynolds number of flow outer boundary layer is larger than unity, and consequently, the inertial forces are larger than the viscous. When the wind is flowing on the boom surface, the boundary layer is growing downstream and the turbulence and adverse pressure gradients produce the separation of the boundary layer and the detachment of flow, as it can be observed in **Figure 8**. In this situation, wind is flowing over booms in very complex conditions to be simulated analytically and the flow coming to each side of boom depends on the incidence angle of wind, so that thermal sensors are operating in a no ideal condition and heat transfer mechanisms are far from a theoretical environment. It is because the booms are calibrated isolated in order to characterize the output electrical signals from sensor when they are subjected to different wind conditions.

**Figure 8.** *Boundary layer over the boom.*


**4. Oncogene-Induced Silencing of Immune Genes by DNA Methylation**

Methylation of cytosines within CpG dinucleotides is a highly abundant epigenetic modification of mammalian genomes [141]. Methylation patterns, which regulate gene expression, are dynamically regulated via the opposing activities of enzymes that introduce or remove this modification, known as 'writers' and 'erasers', respectively. This regulatory apparatus is complemented by chromatin 'readers', i.e., protein modules that recognize histone and DNA modifications [142]. In accord with the deregulation of methylation in cancer development, DNA methyl transferases (DNMTs, 1, 3A and 3B) are overexpressed in many tumors [143–146]. A connection between tumorigenic features of cancer cells, epigenetic silencing and defects in antiviral responses is already observed upon spontaneous immortalization of fibroblasts which results in epigenetic silencing of ISGs [147]. Numerous studies reported on promoter methylation and down regulation of different IRFs (e.g., different combinations of IRF4, IRF5, IRF6, IRF7) in cancers, including fibrosarcoma [148], melanoma [149], lung cancer [150], and gastric cancer [151]. Similarly, the promoter of IFN-γ was shown to be methylated in cervical cancer [104]. Moreover, our analysis of the TCGA skin cutaneous melanoma (SKCM) database revealed significantly higher methylation of promoters of genes presenting highly-correlated expression with STAT1 (a gene group that is enriched for cell autonomous immunity genes), as compared to randomly selected genes [152]. In accord with its tumor-promoting functions, RAS was termed as "silent assassin", due to its gene silencing abilities in cancer cells [153]. In this context, DNMT1 expression is transcriptionally regulated by RAS-induced signaling pathways [143,154,155]. RAS-mediated transformation also modulates the function of DNA-methylation readers such as MBD2 [156]. Furthermore, the expression of enzymes that revert DNA methylation (ten-eleven translocation (TET) methylcytosine dioxygenases) is also regulated by oncogenic signaling in general, and RAS signaling in particular; and ERK-mediated suppression of TET1 is required for K-RAS-induced cellular transformation and hypermethylation of DNA [157]. In accord with a functional interaction between RAS and DNMTs in mediating pro-tumorigenic features, a genome-wide RNA interference (RNAi) screen in K-RAS-transformed NIH-3T3 cells identified DNMT1 and members of the RAS/MEK pathway (ERK2 and MAP3K9) as required for the silencing of the pro-apoptotic FAS gene [158]. The role of such functional interaction in mediating the suppression of

immune responses is observed in the downregulation of the RAS-effector MYC and the upregulation of ISGs in lung cancer, following DNMT inhibition [159]. Interestingly, promoter methylation of IRF7 and enhancement of viral infection was observed in nasal epithelial cells exposed to cigarette smoke [160], suggesting that exposure to carcinogens may already set the stage for the silencing of immune genes observed in malignant cells.


**2.9 Is there a triple-negative paradox?**

Higher Ki-67 predicts a higher response to chemotherapy and a higher pCR rate, which generally means a good prognosis [21]. However, high Ki-67in TNBC is

*Inter-Relationship of Ki-67 and Triple-Negative Breast Cancer DOI: http://dx.doi.org/10.5772/intechopen.109586*

associated with poor recurrence-free or overall survival. This was termed as a "triple negative paradox." However, this paradox can be explained by a higher likelihood of relapse in patients whose pCR was not achieved. In a study by Keam et al., only 18.2% of TNBC patients achieved pCR, and patients with high Ki-67 residual disease had statistically significant poor prognoses than patients with residual disease and low Ki-67 or patients with pCR with high Ki-67 [28]. Similarly, in a study by Carey et al., only 27% of patients with basal subtype achieved pCR [32]. Therefore, in patients with TNBC, the higher number of non-pCR patients tilt the results toward poor prognoses resulting in the so-called "triple negative paradox."

Only 20–30% of patients with TNBC achieved pCR on neoadjuvant chemotherapy [21, 32], and pCR was strongly associated with prolonged overall survival [15, 33, 34]. Moreover, patients with TNBC who achieve pCR have the same prognosis as patients with non-TNBC [33]. However, among patients who did not achieve pCR, patients with TNBC have a significantly poorer outcome than patients with non-TNBC [33].

#### **3. Conclusions**

Although marred by intratumoral heterogeneity and inter-observer variability, true to the highly proliferative nature of TNBCs, higher baseline Ki-67 levels are seen as compared to luminal tumors. A higher Ki-67 is associated with a higher pCR rate in TNBC. However, the best cutoff point of this marker as a prognostic and predictive factor in TNBC remains to be seen even after many researchers have explored this idea. Moreover, the "triple negative paradox" concept is more of a myth arising from more non-pCR patients in the TNBC group.

#### **Acknowledgements**

Thanks to Dr. Biswajit Dubashi , Professor, Department of Medical Oncology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry, India, for reviewing the manuscript and suggesting improvements.

#### **Conflict of interest**

The authors declare no conflict of interest.

#### **Acronyms and abbreviations**


Nanostructures in Energy Generation, Transmission and Storage

*Edited by Yanina Fedorenko*

**NANOSTRUCTURES IN**

**ENERGY GENERATION,**

**TRANSMISSION AND**

Edited by **Yanina Fedorenko**

**STORAGE**