**5. Conclusion**

248 Toxicity and Drug Testing

DJ-1-deficient mice treated with PQ, decreased proteasome activities and increased ubiquitinated protein levels were found, and these pathologies were not observed in brain regions of normal mice treated with PQ (Yang *et al.*, 2007). In another mouse study, the loss of DJ-1 increased the sensitivity to oxidative insults but did not produce neurodegeneration. Similar results have been found when analysing *Drosophila melanogaster* mutants for the DJ-1 orthologous genes, DJ-1alpha and DJ-1beta, that resulted in increased sensitivity to PQ insults, reduced lifespan and motor impairments. However, these mutations did not lead to

In 2002, *PARK8* gene mutations were discovered as a major genetic cause associated with hereditary parkinsonism (Paisan-Ruiz *et al.*, 2004). The *PARK8* gene was associated with PD in studies of a Japanese Sagamihara family who responded positively to treatment with L-DOPA, which had parkinsonism that presented with an unknown aetiology of the disease (Funayama *et al.*, 2002). Other studies examined two additional families (German and Canadian) who also had an autosomal dominant, late-onset parkinsonism (Zimprich *et al.*,

In the LRRK2 structure, two functional domains, kinase and GTPase domains, were shown to be present. The G2019S mutation was present in the kinase domain specific to the binding site for Mg2+ (Kachergus *et al.*, 2005). This mutation facilitates the access of the kinase domain to its substrates, which increases autophosphorylation 2.5-fold the phosphorylation of other substrates, such as myelin basic protein (MBP), 3-fold for the LRRK2 autophosphorylation without the presence of this mutation (Jaleel *et al.*, 2007; West *et al.*, 2005), which is responsible for the increased toxicity of this molecule (Greggio *et al.*, 2006). In the GTPase domain, the R1441C has been the most studied mutation, and there is controversy as to the influence of GTPase mutations on the kinase activity that was observed in some studies in which the increase was similar (Guo *et al.*, 2007) or had no

LRRK2 has been shown to play different roles in the cell; however, little information is available. Based on the data we found from the protein interactions, there was a relationship between LRRK2 and cytoskeletal reorganisation (Gandhi *et al.*, 2008), maintenance functions and cell morphology (Plowey *et al.*, 2008), protein transport through synaptic vesicles (Shin *et al.*, 2008), and the ubiquitination process (Ko *et al.*, 2009). There have also been studies that relate LRRK2 and apoptosis (Ho *et al.*, 2009). Previous studies have shown a relationship between LRRK2 and other PD-related proteins, such as parkin (Ng *et al.*, 2009; W. W. Smith *et al.*, 2005), PINK-1 and DJ-1 (Venderova *et al.*, 2009) or α-synuclein (X. Lin *et al.*, 2009). The interaction of LRRK2 with PQ is not clear. Studies in *Drosophila melanogaster* in which the deletion of kinase domain of LRRK2 did not induce a higher sensitivity to the PQ stimulus has been shown (D. Wang *et al.*, 2008). In contrast, in *Caenorhabditis elegans* studies, the expression of human LRRK2 protein protected against PQ, which increased nematode survival in response to agents that cause mitochondrial dysfunction. However, protection by G2019S, R1441C, or kinase-dead LRRK2 was less effective than wild-type LRRK2 (Saha *et al.*, 2009). In another study with *Caenorhabditits elegans, PINK1* mutant genes have been observed in a minor mitochondrial length and increased PQ sensitivity of the nematode. Moreover, the mutants also displayed defects in axonal outgrowth of a pair of canalassociated neurons. We demonstrated that in the absence of lrk-1 (the *C. elegans* homologue

dopaminergic neuronal loss (Lavara-Culebras & Paricio, 2007)

**4.4 LRRK2 (PARK8) and paraquat**

change (Jaleel *et al.*, 2007).

2004).

PQ has been suggested as a potential aetiological factor for the development of PD. We have demonstrated that PQ was able to induce cell death by activating apoptotic machinery. However, PQ also displayed characteristics of autophagy, a degradative mechanism involved in the recycling and turnover of cytoplasmic constituents from eukaryotic cells. Finally, the cells suffered apoptotic death when the PQ remained.  These findings suggest a relationship between autophagy and apoptotic cell death following paraquat exposition and allows us to further investigate and increase our knowledge regarding the toxicity of paraquat and its relationship with the origin of PD.


**1. Introduction**

#### **1.1. Motivation for cell sorting**

The cell is the basic functional unit within a tissue or an organ. Methods that can be used to probe the cell, so as to understand, or even manipulate its interrelated processes, pathways, and/or overall functioning, are of great scientific and commercial value. Research efforts in molecular biology, biochemistry, and biotechnology over the last two decades have created high demand for efficient, cost-effective, cell enrichment, isolation, and handling methods. Cell studies can be performed on continuously growing cell lines, many of which are commercially available, in tissue culture, or on cells obtained from intact tissues or isolated from blood [1-3].

Mammalian cells are highly heterogeneous in structure, function, and characteristics. However, many types of biochemical, pharmaceutical, and clinical studies, such as immunophenotyping, studies of the cell cycle, cell proliferation, or apoptosis, and other specialized cell analyses require a homogenous population consisting of a single cell type; as the analyte. Only then can the results deemed accurate and specific to the cell type under investigation [4, 5]. Accordingly, techniques to separate cell types in a heterogeneous cell population are of immense practical value. Any such efforts are further complicated when the target cell is rare within a population such as in many cancer and prenatal diagnosis applications. The more stringent the requirements for specific and precise cell separation, the greater the degree of accuracy and reproducibility required in the technology that underlies the separation method [6-8].

Recent progress in microfabrication, technologies developed and utilized by the integrated circuits (ICs) industry, is being exploited to biomedicine, spawning a relatively new field of research that has become known as BioMEMS. Microfabricated devices have already had a

© 2012 Mohamed, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 Mohamed, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

broad range of biomedical and biological applications [9, 10]. These devices can be manufactured with a reproducible accuracy of less than 1 micrometer (1/100th the diameter of a human hair). In the last decade, microchips have been used in a huge range of devices and contexts: microscale sensors for surgical instruments, monitoring of physiological activities, drug discovery and delivery, DNA amplification, and electrophoresis, as well as cell sorting, the application discussed in this chapter [11-16].

Use of Microfluidic Technology for Cell Separation 197

denotes a

shape. The change in shape and the increased rigidity of the RBCs lead to obstruction of capillaries, thereby restricting blood flow to organs, causing anemia and other "sickle cell crisis", and decreasing life expectancy. Cancer is a second example of such changes [20]. Malignant tumor cells differ from benign tumor cells in structure, growth rate, invasiveness, and their ability to metastasize. Benign tumor cells grow slowly, pushing neighboring tissues away while staying well encapsulated. In contrast, malignant tumor cells grow rapidly, invade neighboring tissues, and may metastasize [21]. Furthermore, they generally are irregular in shape, and exhibit a more "rugged" or "ruffled" surface appearance than do normal cells [22, 23]. Cancer is detected and diagnosed based on physical changes present in tissues and cells. Nuclear changes such as an increase in size, deformation, and a change in internal organization are among the most universal criteria for detecting malignancy [24-25]. These changes may reflect alterations in the nuclear matrix and the connections of the nuclear matrix to or via the cytoskeleton. Cancer cells modify their morphology, principally by increasing the size of the nucleus, before they become invasive, i.e., in dysplasia and carcinoma *in situ*. The nucleus of a dysplastic cell can be up to four times as large as that of a non-dysplastic cell. Accordingly, light scattering microscopy has been used to distinguish normal, dysplastic, and cancerous epithelial cells in a range of tissues including esophagus, colon, bladder, and oral cavity [26]. However, this technique can only succeed if a sufficient

Additionally, most cell types have characteristic complements of surface molecules. Among the most useful for identification is the cluster of differentiation (CD), or cluster of designation. CD molecules have roles in signaling and adhesion processes, and the specific compliments of CD molecules is a determinant of the specific function of the cell. Cell populations are usually denoted by a pattern of "+" or a "-"scorings; indicating the presence

cell that expresses CD34 but not CD31. Use of more than one marker can make the cell selection very specific. However, not all cell types have a known specific surface marker

For some cells such as cancer cells, not many cell-surface markers have been identified. In such a situation, some techniques have used a surface marker directed against surface membrane antigens that are expressed in tissue of origin, which is most often epithelial. Thus, detection of these tissue-specific surface markers in the blood stream is suggesting that cancer cells have detached from the tumor. Some techniques attempting to isolate circulating tumor cells (CTCs) from whole blood have used EpCAM, an epithelial cell adhesion molecule that is overexpressed in epithelial carcinomas such as colon and breast. However, published studies have shown inconsistent frequency of EpCAM expression in breast cancer, from as low as 35% to as high as 100% [28-31]. Thus, EpCAM cannot be considered a CTC specific marker. Additional bio-molecules such as DAPI (nucleic acid stain) and antibodies against cytokeratin (expressed on the epithelial cell membrane) and CD45 (expressed on the majority of hematopoietic cells) must be used if captured cells are to be positively identified as CTC. Therefore a cell with the phenotype EpCAM+, DAPI+, CK+,

or absence of specific CD molecules. For example, a nomenclature of CD34+, CD31-

number of cells are available for analysis.

and CD45- is considered a CTC.

[27].

Microfluidic technology, a subcategory of BioMEMS, is a set of techniques and processes for making devices to precisely control and manipulate fluid in a geometrically small channels; sub- to few hundred- micrometers in size. Microfluidic is multi-disciplinary; developing a device with biological utility requires the integration of knowledge and techniques from the fields of engineering, biology, physics, and chemistry. Such microfabricated devices are used to study biological systems and to generate new insights into how these systems work. Conversely, the biological knowledge gained through micro/nano - scale analyses can lead to further improvements in device design. BioMEMS is a challenging field because the materials, and chemistries, important for biological microfluidics applications are so diverse [17, 18].

The objective of the present chapter is to introduce the principals of cell sorting by microfluidic technology, and to discuss its strengths, current limitations, and current and potential applications, with illustrative examples from the literature and from the author's laboratory.

#### **1.2. Challenges in cell sorting**

Cells of different types have characteristic sizes, shapes, densities, and arrays of surface molecules that can be exploited for sorting. For example, red blood cells (RBCs) are the cells responsible for delivering oxygen to the tissues. RBCs have to squeeze through capillaries and therefore are relatively small, approximately 6-8 µm in diameter, and flexible. Mature RBCs are anucleate; the maturing cells lose their nuclei before leaving the bone marrow. Loss of the nucleus leads to cell membrane collapse, conferring the characteristic biconcave shape of RBCs, and giving the cell a greater surface area to volume ratio than of spherical cells. These physical features allow easier movement of oxygen (O2) and carbon dioxide (CO2) through the membrane. RBCs are composed mainly of hemoglobin, whose iron atoms temporarily bind O2 molecules in the lungs, and then release the molecules throughout the body. RBCs have the highest density of any cell type in blood. All of the above characteristics can be used for separation: for example size can be used to separate RBCs since they are smaller and more flexible than white blood cells (WBCs). RBCs' high density causes them to spin down to the bottom of a test tube after density gradient centrifugation. The high iron content gives RBCs intrinsic magnetic properties and can be used for magnetic separation [19].

In other cases, a cell changes its shape or size as a result to a disease or change in function. In sickle-cell disease, a genetic blood disorder, RBCs assume an abnormal, rigid, sickle shape. The change in shape and the increased rigidity of the RBCs lead to obstruction of capillaries, thereby restricting blood flow to organs, causing anemia and other "sickle cell crisis", and decreasing life expectancy. Cancer is a second example of such changes [20]. Malignant tumor cells differ from benign tumor cells in structure, growth rate, invasiveness, and their ability to metastasize. Benign tumor cells grow slowly, pushing neighboring tissues away while staying well encapsulated. In contrast, malignant tumor cells grow rapidly, invade neighboring tissues, and may metastasize [21]. Furthermore, they generally are irregular in shape, and exhibit a more "rugged" or "ruffled" surface appearance than do normal cells [22, 23]. Cancer is detected and diagnosed based on physical changes present in tissues and cells. Nuclear changes such as an increase in size, deformation, and a change in internal organization are among the most universal criteria for detecting malignancy [24-25]. These changes may reflect alterations in the nuclear matrix and the connections of the nuclear matrix to or via the cytoskeleton. Cancer cells modify their morphology, principally by increasing the size of the nucleus, before they become invasive, i.e., in dysplasia and carcinoma *in situ*. The nucleus of a dysplastic cell can be up to four times as large as that of a non-dysplastic cell. Accordingly, light scattering microscopy has been used to distinguish normal, dysplastic, and cancerous epithelial cells in a range of tissues including esophagus, colon, bladder, and oral cavity [26]. However, this technique can only succeed if a sufficient number of cells are available for analysis.

196 Blood Cell – An Overview of Studies in Hematology

[17, 18].

laboratory.

separation [19].

**1.2. Challenges in cell sorting**

cell sorting, the application discussed in this chapter [11-16].

broad range of biomedical and biological applications [9, 10]. These devices can be manufactured with a reproducible accuracy of less than 1 micrometer (1/100th the diameter of a human hair). In the last decade, microchips have been used in a huge range of devices and contexts: microscale sensors for surgical instruments, monitoring of physiological activities, drug discovery and delivery, DNA amplification, and electrophoresis, as well as

Microfluidic technology, a subcategory of BioMEMS, is a set of techniques and processes for making devices to precisely control and manipulate fluid in a geometrically small channels; sub- to few hundred- micrometers in size. Microfluidic is multi-disciplinary; developing a device with biological utility requires the integration of knowledge and techniques from the fields of engineering, biology, physics, and chemistry. Such microfabricated devices are used to study biological systems and to generate new insights into how these systems work. Conversely, the biological knowledge gained through micro/nano - scale analyses can lead to further improvements in device design. BioMEMS is a challenging field because the materials, and chemistries, important for biological microfluidics applications are so diverse

The objective of the present chapter is to introduce the principals of cell sorting by microfluidic technology, and to discuss its strengths, current limitations, and current and potential applications, with illustrative examples from the literature and from the author's

Cells of different types have characteristic sizes, shapes, densities, and arrays of surface molecules that can be exploited for sorting. For example, red blood cells (RBCs) are the cells responsible for delivering oxygen to the tissues. RBCs have to squeeze through capillaries and therefore are relatively small, approximately 6-8 µm in diameter, and flexible. Mature RBCs are anucleate; the maturing cells lose their nuclei before leaving the bone marrow. Loss of the nucleus leads to cell membrane collapse, conferring the characteristic biconcave shape of RBCs, and giving the cell a greater surface area to volume ratio than of spherical cells. These physical features allow easier movement of oxygen (O2) and carbon dioxide (CO2) through the membrane. RBCs are composed mainly of hemoglobin, whose iron atoms temporarily bind O2 molecules in the lungs, and then release the molecules throughout the body. RBCs have the highest density of any cell type in blood. All of the above characteristics can be used for separation: for example size can be used to separate RBCs since they are smaller and more flexible than white blood cells (WBCs). RBCs' high density causes them to spin down to the bottom of a test tube after density gradient centrifugation. The high iron content gives RBCs intrinsic magnetic properties and can be used for magnetic

In other cases, a cell changes its shape or size as a result to a disease or change in function. In sickle-cell disease, a genetic blood disorder, RBCs assume an abnormal, rigid, sickle Additionally, most cell types have characteristic complements of surface molecules. Among the most useful for identification is the cluster of differentiation (CD), or cluster of designation. CD molecules have roles in signaling and adhesion processes, and the specific compliments of CD molecules is a determinant of the specific function of the cell. Cell populations are usually denoted by a pattern of "+" or a "-"scorings; indicating the presence or absence of specific CD molecules. For example, a nomenclature of CD34+, CD31 denotes a cell that expresses CD34 but not CD31. Use of more than one marker can make the cell selection very specific. However, not all cell types have a known specific surface marker [27].

For some cells such as cancer cells, not many cell-surface markers have been identified. In such a situation, some techniques have used a surface marker directed against surface membrane antigens that are expressed in tissue of origin, which is most often epithelial. Thus, detection of these tissue-specific surface markers in the blood stream is suggesting that cancer cells have detached from the tumor. Some techniques attempting to isolate circulating tumor cells (CTCs) from whole blood have used EpCAM, an epithelial cell adhesion molecule that is overexpressed in epithelial carcinomas such as colon and breast. However, published studies have shown inconsistent frequency of EpCAM expression in breast cancer, from as low as 35% to as high as 100% [28-31]. Thus, EpCAM cannot be considered a CTC specific marker. Additional bio-molecules such as DAPI (nucleic acid stain) and antibodies against cytokeratin (expressed on the epithelial cell membrane) and CD45 (expressed on the majority of hematopoietic cells) must be used if captured cells are to be positively identified as CTC. Therefore a cell with the phenotype EpCAM+, DAPI+, CK+, and CD45- is considered a CTC.

The number of available cells of interest poses and additional challenge; in some applications such as the isolation of CTCs from cancer patient or fetal nucleated red blood from maternal circulation, only 1-2 cell are available per milliliter (mL) of whole blood. Specificity is problematic for either method, due to the lack of a cell-specific surface marker/antibody to exclusively detect CTCs or fetal cells [32].

Use of Microfluidic Technology for Cell Separation 199

safer than "macro" platforms due to the smaller chemical quantities used and hence the lower stored energies. A microfluidic device that performs one assay is typically referred to as Lab-on-a-chip, while a device that integrates more than one step is referred to as micro

This section will briefly describe the basic concepts in the microfabrication of microfluidic devices. Microfabrication is the already subject of many textbooks and the interested reader can consult one of these for more in-depth details [33, 34]. Microfabrication is the technology developed by ICs industry to make devices and circuits with feature sizes as small as 14 nm in research, and 45 nm in production. Among these are the microprocessors and the electronic components found in computers, smart phones, television sets, and major other electronic products. Microfabrication is also used for MEMS devices (micro-electro mechanical systems), devices that include a movable part and can be used for sensing. The airbag sensor used to deploy an airbag in a vehicle, the pressure sensors inside car tires, and the electronic compass in a smart phone are all examples of MEMS devices that we unknowingly use every day. BioMEMS, microfluidic devices, and µTAS are all microfabricated devices similar to MEMS but customized for biological and chemical

Creation of a a new microfluidic device includes design of the channel(s), fluid inlet(s) and outlet(s), using a CAD (computer-aided design) software. These softwares, such as CoventorWare® [35], ANSYS CFD [36], COMSOL Multiphysics® [37], can be also used for simulation of the various design parameters such as device dimensions, heat transfer, and flow conditions, therefore narrowing the design space range in which optimum performance should be obtained. The pattern of channels is laid out with the CAD software; this is the 2D design of the device. The depth of the channel will be determined by the etching time. The drawings are transferred to a mask, typically a glass or quartz plate (transparent to UV light), covered with chrome. The chrome is etched (removed) where the UV light will expose the photoresist. The mask, similar to a stencil, transfers the pattern to the photoresist. The device is built on a substrate, which is a silicon, glass or quartz wafer, or a regular glass slide. After substrate cleaning, the photoresist, a photosensitive polymer, is applied. Photoresist is dispensed onto the substrate and it is spun at high speed (2000- 4000rpm) to create a thin (1-100 micrometer), uniform and smooth layer. The mask is placed in contact with the substrate and exposed to UV lights on a mask aligner. The photoresist is developed in a developer solution specific for it, and is removed from areas exposed to UV light (positive photoresist). The channels can be etched, with substrate material being removed from areas unprotected by the photoresist. Etching can be either wet (using chemicals) or dry (plasma etching). Deep reactive ion etching (DRIE) is a plasma etching technique typically used to achieve deep channels with vertical side walls. Use of DRIE is necessary if the etched substrate will serve as a template for molding devices in polymer such that the polymer mold can be peeled off the substrate. At this stage, the device can be

total analysis system (µTAS) [18].

applications.

**2.2. Introduction to microfabrication**

Despite great successes, cell sorting techniques are not ideal and therefore remain an active area of research. In addition to sensitivity and specificity requirements, an ideal technique should not be overly labor intensive, should be automated and quantitative, the results should predict clinical outcome, and help the physician personalize therapeutic options. Automating sample preparation and handling would minimize human errors. Integration of preparation, cell sorting, and post processing will lead to more cost-effective instruments, and alleviate the need for trained personnel and infrastructure. Microfluidic technology enables the precise control over the cell microenvironment during separation, scales down the analyses to very small volume of blood, and has the potential for high-throughput to cell separation and analyses.


**5. Risk factors**

It seems that young women (<25 years old) are more prone to chlamydial infection due to anatomic differences in the cervix, such as cervical ectropion [16, 26]. In this condition, the glandular cells that line the endocervix are present on the ectocervix, leading to exposure of the glandular cells to the vaginal milieu and C. trachomatis has a preference for the glandular epithelium [5, 27].

Regarding infants, the main risk factor is vertical transmission (mother-tochild) after vaginal birth. Transmission after a cesarean section is unusual, unless premature rupture of the membranes of an infected mother is reported.


*Article* **Heme-Oxygenase-1 Attenuates Oxidative Functions of Antigen Presenting Cells and Promotes Regulatory T Cell Differentiation during** *Fasciola hepatica* **Infection**

**Monique Costa , Valeria da Costa, Sofía Frigerio, María Florencia Festari, Mercedes Landeira, Santiago A. Rodríguez-Zraquia, Pablo Lores, Paula Carasi and Teresa Freire \***

> Laboratorio de Inmunomodulación y Desarrollo de Vacunas, Departamento de Inmunobiología, Facultad de Medicina, Universidad de La República, Montevideo 11800, Uruguay<EMAIL_ADDRESS>(M.C<EMAIL_ADDRESS>(V.d.C<EMAIL_ADDRESS>(S.F<EMAIL_ADDRESS>(M.F.F<EMAIL_ADDRESS>(M.L<EMAIL_ADDRESS>(S.A.R.-Z<EMAIL_ADDRESS>(P.L<EMAIL_ADDRESS>(P.C.)

**\*** Correspondence<EMAIL_ADDRESS>Tel.: +598-2-924-9562

**Abstract:** *Fasciola hepatica* is a fluke that infects livestock and humans causing fasciolosis, a zoonotic disease of increasing importance due to its worldwide distribution and high economic losses. The parasite regulates the host immune system by inducing a strong Th2 and regulatory T (Treg) cell immune response through mechanisms that might involve the expression or activity of heme-oxygenase-1 (HO-1), the rate-limiting enzyme in the catabolism of free heme that also has immunoregulatory and antioxidant properties. In this paper, we show that *F. hepatica*-infected mice upregulate HO-1 on peritoneal antigen-presenting cells (APC), which produce decreased levels of both reactive oxygen and nitrogen species (ROS/RNS). The presence of these cells was associated with increased levels of regulatory T cells (Tregs). Blocking the IL-10 receptor (IL-10R) during parasite infection demonstrated that the presence of splenic Tregs and peritoneal APC expressing HO-1 were both dependent on IL-10 activity. Furthermore, IL-10R neutralization as well as pharmacological treatment with the HO-1 inhibitor SnPP protected mice from parasite infection and allowed peritoneal APC to produce significantly higher ROS/RNS levels than those detected in cells from infected control mice. Finally, parasite infection carried out in gp91phox knockout mice with inactive NADPH oxidase was associated with decreased levels of peritoneal HO-1<sup>+</sup> cells and splenic Tregs, and partially protected mice from the hepatic damage induced by the parasite, revealing the complexity of the molecular mechanisms involving ROS production that participate in the complex pathology induced by this helminth. Altogether, these results contribute to the elucidation of the immunoregulatory and antioxidant role of HO-1 induced by *F. hepatica* in the host, providing alternative checkpoints that might control fasciolosis.

**Keywords:** helminth; heme-oxigenase-1; immunoregulation; antigen presenting cell; regulatory T cell; ROS/RNS


*2.2. Animals and Treatment*

Adult male Sprague Dawley rats (*n* = 24) were randomly distributed in t-BHP and control groups and were treated with 300 μmoles tert-BHP/kg b.w. or saline (control) once a day intraperitoneally for 15 days, respectively as done previously [18]. Treatment with tert-BHP showed to have no effects on the health of rats [18,24]. Animals were euthanized at 3, 6, and 9 weeks post-treatment. These end

points correspond to late, middle and early spermatogenesis, respectively [25]. At each given end time, reproductive organs were collected, weighted and kept at −80 ◦C until use. For sperm motility determination, cauda epididymes were cut one time at the base with a surgical blade and placed in phosphate-bu ffered saline (PBS; 1 mM KH2PO4, 10 mM Na2HPO4, 137 mM NaCl, 2.7 mM KCl, pH 7.4) at 37 ◦C. Spermatozoa were allowed to swim-out for 10 min and were collected in clean tubes. All procedures with rats (handling, euthanasia, collections of tissues, etc.) were carried out following the regulations of the Canadian Council for Animal Care (CACC) and according the protocol #2009-5656 approved by the Facility Animal Care Committee (FACC) of the Research Institute, McGill University Health Centre.

### *2.3. Testes and Epididymes Homogenates Preparation*

Control and t-BHP treated adult male Sprague-Dawley rats' frozen testis, caput and cauda epididymis were thawed, weighed and homogenized in a glass potter in RIPA bu ffer containing protease inhibitors. The samples were then sonicated for 20 s at 30% amplitude twice with 20 s intervals with a Sonic Vibracell (Sonics and Materials, Inc., Newtown, CT, USA). The samples were centrifuged at 21,000× *g* for 20 min at 4 ◦C. The supernatant was extracted, aliquoted and stored at −80 ◦C.

### *2.4. Sperm Motility and DNA Oxidation Determinations*

Sperm motility was assessed by the same observer (CO) using the Olympus BH-2 microscope at 100 magnification with a thermal plate at 37 ◦C. At least 200 spermatozoa per duplicate were analyzed to determine percentage of total motility in each sample [18]. Sperm DNA oxidation was determined by immunohistochemistry using the anti-8-OHdG antibody as done previously [18]. Briefly, sperm samples were centrifuged at 2000× *g* for 5 min to remove the PBS medium and resuspended in 20 mM phosphate bu ffer (pH 6.0) with 1 mM EDTA for 5 min. Samples were then centrifuged and resuspended in 50 mM Tris-HCl (pH 7.4), 1% SDS and 40 mM dithiothreitol for 30 min. Final centrifugation of 5 min to replace the mixture with PBS was performed. The sperm PBS solution was smeared on Superfrost Plus slides (Fischer Scientific, Ottawa, ON, Canada) and they were fixed with 100% methanol at 20 ◦C for 30 min. Slides were incubated with 5% horse serum for 30 min at room temperature, then washed with PBS-T for 5 min and incubated with anti-8-OHdG antibody (1:100) (SMC-155D, StressMarq Biosciences Inc., Victoria, BC, Canada) diluted in 1% horse serum overnight at 4 ◦C. After a wash with PBS, the samples were incubated with biotinylated horse anti-mouse antibody in 1% BSA and PBS-T for 1 h, washed and finally incubated with Alexa Fluor 555-streptavidin (1:500 in PBS) for 45 min at 20 ◦C. ProLong Gold antifade with DAPI was added and smears sealed. Slides were analyzed with Zeiss Axiophot fluorescence microscopy (Carl Zeiss, Oberkochen, Germany). Two hundred spermatozoa per slide were counted in duplicate. A positive control was done by incubating spermatozoa with 2 mM H2O2 for 1 h at 37 ◦C. The specificity of the antibody was confirmed previously [18].

### *2.5. Testes Histological Analysis, and Sperm Count*

Testes were dissected, weighed, and fixed immediately with Bouin fixative for 24 h before processing and embedding in para ffin blocks, and tissues were sectioned (5 μm) and stained with hematoxylin-eosin as previously described [26]. Spermatozoa heads from testis homogenates were counted in a hematocytometer as previously described [27].


**5. Conclusions**

This study examined the current state of the use of new-media marketing among ornamental horticulture businesses. The sample of 161 businesses, while lacking in representativeness of those that are involved in new-media marketing without social media, offers insight that can be used to develop outreach programs or future research projects.

New-media marketing, with its cost structure and extensive reach, offers a game-changing opportunity, particularly for smaller businesses in ornamental horticulture industries. Studies suggest enormous potential if a new-media marketing strategy is skillfully employed. For example, the search for gardening information through the internet increased a customer's likelihood to purchase horticultural products online by 19% [5]. The task ahead is for research efforts to assist the ornamental horticulture industries in identifying the most effective practices for its members of various size and by specific business type.

As with any study, there were some limitations that should be noted. The sampling in the study was limited to those business that responded, which resulted in 161 total usable responses. This offered a reasonable amount in order to generalize to the larger population, with a confidence interval of 7.68 at a 95% confidence rate. However, there are likely some businesses who do not match the findings in this study. Future work to build on this exploratory study should seek a stratified random sample across all ornamental horticulture business types. Additionally, there were some variables that would have been valuable to the study that were left out due to survey length. These include items such as details about business-type and economic data beyond self-reported data.

**Author Contributions:** H.P., C.B., and L.B. obtained funding, designed the study, and completed manuscript writing. B.Y. planned, deployed the survey, analyzed the data, and wrote the first draft of the manuscript. H.P. analyzed the data and revised the manuscript. C.B. assisted with survey deployment to stakeholders across the United States, corresponded, and finalized the manuscript.

**Funding:** This research was supported by the United States Department of Agriculture—Agricultural Marketing Service—Federal State Marketing Improvement Program (number 11402984), James L. Whitten Building 1400 Independence Ave., S.W. Washington, DC 20250. Contribution no. 16-338-J from the Kansas Agricultural Experiment Station.

**Acknowledgments:** The Kansas State University Center for Rural Enterprise Engagement coordinated research, teaching, and extension activities related to this project.

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


*6.1. Uncertainties*

In confined salt-bearing basins, such as the Nordkapp Basin, seismic imaging and interpretation of salt bodies are certainly challenging due to the steeply dipping diapir flanks and complex ray paths of the seismic waves travelling through the salt [55,56]. Consequently, poor seismic imaging of salt structures can lead to incorrect interpretation of their shapes, which undoubtedly has negative consequences for determining the progressive evolution and thermal effect of salt structures through time. Uncertainty also arises from depth conversion of the seismic profiles. Figure 3A displays a wide range of interval velocities due to lateral variations in lithology and different degrees of compaction and diagenesis. In addition, the velocities of deep sediments within the Nordkapp minibasins are unknown because there are no exploration wells through the entire minibasins stratigraphy. Despite these uncertainties, the velocity model used in this study provides similar results (depths) to previous magnetic and gravity studies by Gernigon et al. [23] in the Eastern Barents Sea.

2D structural reconstructions involve several uncertainties associated with the type of unfolding method (flexural slip vs simple shear), decompaction curves, water depth, and elastic thickness. Testing different restoration parameters will indeed result in different paleogeometries. However, the objective of this paper is not to test the sensitivity of model parameters but rather use reasonable parameter values. For example, we use simple shear to remove the deformation caused by passive diapirism because the length loss adjacent to salt diapirs is negligible compared to the length of the section. On the other hand, we use flexural slip in sequences SU2 and SU3 because it preserves length in these parallel-folded units [57]. Based on studies by Klausen and Helland-Hansen [58], we use the Sclater and Christie [51] decompaction curve because it fits well the porosity versus depth trends observed on borehole data in the Barents Sea. Finally, an elastic thickness of 20 km was chosen based on Gac et al. [41].

In terms of thermal modeling, most of the crucial stages (IV to VIII) for the formation of the Nordkapp Basin encompass a relatively short (~20 Ma) and old (Permian-Early Triassic) time interval (Figure 5D). Therefore, restoring sensible boundary conditions (basal heat flow and SWTI) for this period is crucial. Inevitably, assumptions are intrinsic to the model due to the general lack of calibration data, with the exception of a few bottom well temperatures and vitrinite data (Figure 6). Extrapolating boundary conditions calculated in the western sub-basin to the central and eastern sub-basins can be unrealistic, since the initial thickness of the Post-Caledonian crust and lithosphere, and the amount of rifting defined by β most likely varied along the basin [42]. Additional uncertainty arises from the need to simplify lithologies, particularly for the deepest units, given the importance of their thermal conductivities and heat capacities in the simulations.

On the other hand, the model, as designed, would greatly benefit from assessing the distribution and thickness of the source rocks in each of the minibasins. For the petroleum system, the evaluation of the actual presence of good reservoir levels in the basin is a must. Despite these limitations, the modeling results represent the Nordkapp Basin geology and tectonic evolution, and they can be used to develop further exploration concepts in this basin and other basins alike.

### *6.2. The Importance of Thermal Modeling in Confined Salt-bearing Basins*

The thermal e ffect of salt structures has been documented by previous studies in passive margins such as the Gulf of Mexico [6,9]. In this tectonic setting, salt deposition occurs in unconfined large areas where accommodation is controlled by thermal subsidence [59]. This also produces tilting of the margin, which in turn triggers downslope salt gliding and structures such as salt stocks, salt tongues, and allochthonous salt sheets [2]. These structures have received special attention due to their sealing capacity and their impact on maturation of underlying source rocks [6,8–10].

In the case of salt-bearing rift basins, syn-rift salt deposition is really limited by the rift geometry [59]. Salt mobilization by either extension and/or di fferential loading results in a structural style consisting of sub-vertical and closely spaced salt structures, which commonly coincide with the presence of subsalt faults [60–62]. Factors such as diapir shape and spacing play an important role in the thermal evolution of these basins [9].

Combined structural restorations and thermal modeling from the Nordkapp Basin indicate that the shape of salt diapirs and their inherent thermal anomalies vary through time and display a characteristic negative thermal e ffect (i.e., downward shift of isotherms), which is directly proportional to the width of the salt diapir (Figure 7). This is clearly observed in the eastern sub-basin (section B), where the presence of a wider and isolated salt diapir induces a strong, but laterally limited, negative anomaly. Temperatures along the diapir flanks could be up to 70 ◦C cooler and exceptionally low (~150 ◦C) at depths of ~9 km beneath the diapir. This integrated approach also highlights that closely-spaced diapirs in the central sub-basin mutually interfere and produce a combined negative thermal anomaly, which lowers the temperature in the minibasins by up to 50 ◦C with respect to the adjacent platform areas. Thus, although large salt tongues and allochthonus salt sheets are absent in confined basins, sub-vertical and closely spaced salt structures still generate a combined thermal anomaly that extends over large areas of the basin.

### *6.3. Implications for the Petroleum System*

Salt diapirs in confined basins impact the petroleum system by retarding maturation of organic rich sediments, expanding the hydrocarbon generation window, and hindering diagenetic processes in reservoir levels. Figure 11 summarizes the implications of our results for the petroleum system of the Nordkapp Basin.

**Figure 11.** Petroleum systems chart for the Nordkap Basin. Insights from the modeling results are incorporated in the chart.


*4.2.1 Safety review and compliance*

Ensure that all participants have gloves and dust mask. Protective gloves prevent cuts associated with the handling of sharp objects with bare hands. Be clear with your volunteers about how to handle hazardous waste such as pesticide containers, cleaning chemicals containers and sharp objects such broken glass. Closed feet shoes are safer than sandals or flip-flops. Where children will be participating, plan for adequate adult supervision (**Figure 6**).

### **4.3 STAGE 3: After the clean-up**

After, the clean-up, the project coordinator should thank everyone who volunteered their time and effort. A follow up thank you letters should be written to all stakeholders including sponsors who would have assisted. Remind participants to wash their hands especially when refreshments are to be served. Where a handwashing facility is not available, arrangements must be in place for an alternative facility such as a portable water dispenser and soap.

### *4.3.1 Disposing of garbage*

One of the most important aspects, when organising a community clean-up, is organising for removal of trash. Waste should be removed as soon as possible after

#### **Figure 6.**

*Chipadze primary school health Club cleaning up Chipadze shopping Centre.*

**Figure 7.** *Community members clearing a dumpsite during a clean-up campaign.*

the event to prevent the creation of unhygienic conditions and to avoid it becoming an eyesore and an environmental externality (**Figure 7**). It is the responsibility of the project coordinator to make arrangements with the local authority for the collection of garbage collected. Where the local authority is not able to provide haulage service, prior arrangements should be done for alternative methods such as private companies.

#### *4.3.2 Assessment of the results*

It is important to assess the event as soon as possible after it occurs. Success is measured using the indicator listed during the planning stage. A report detailing the number of volunteers (aggregated by sex and age group), hours worked, area covered, illegal dumpsite cleared, weight of waste removed among other indicators should be produced. Including lesson learnt and suggestions should help in improving the next clean-up. It should be remembered to share the results and photographs, where possible, with all stakeholders.


*2.2. Materials*

Dispositional mindfulness was measured using the Italian version of the Five Facets Mindfulness Questionnaire (FFMQ [21]), containing 39 items divided in five subscales: observing, describing, acting with awareness, non-judging, and non-reacting. Participants were requested to rate each statement on a 5-point Likert scale. Higher total scores indicate higher dispositional mindfulness. Following the literature on MAT theory [19,20], we considered monitoring as being represented by observing and acceptance as being represented by non-judging and non-reacting. The psychometric properties of this scale are good [21].

The Italian version of the Hospital Anxiety and Depression Scale (HADS [22]) was administered to assess general distress. The HADS consists of 14 items divided in two subscales: anxiety and depression. Participants are requested to rate how they have been feeling in the past week on a 4-point scale. The psychometric properties of the HADS are good [22]. Following Iani et al. [22], the total score was used as a measure of general psychological distress.

In order to detect sleep quality as well as sleep-related wake disorders, the Italian version of the Mini Sleep Questionnaire (MSQ [23]) was used. In this questionnaire, 6 of the 10 items are related to sleep problems while 4 items are related to wake problems. Respondents had to indicate the frequency of occurrence for each statement in the past week on a 7-point scale. Beyond the total score, as suggested by Natale et al. [23], we also calculated the scores of the sleep and wake subscales. The psychometric properties of the MSQ are good [24].

Given that circadian typology has been shown to influence sleep problems [25], in order to control for such a factor, we also administered the Italian version of the reduced Morningness-Eveningness Questionnaire to measure circadian typology (rMEQ [26]). The rMEQ includes 5 items and the total score is obtained by summing up all the items, with higher scores reflecting a morningness preference. The psychometric properties of rMEQ are good [26].


**7. Spectral responsivity scale in the near IR range based on single InP/ InGaAs photodiodes**

As in the visible range, semiconductor photodiodes are the best choice for establishing spec‐ tral responsivity scales in the near IR range. The first attempt was to use germanium photo‐ diodes, since its gap allowed to obtain a device responding to wavelengths lower than 1.6 μm, approximately, depending on temperature. However germanium photodiodes have got a rather high dark current and lower shunt resistance than silicon, then they are not so use‐ ful for optical radiation detection. Since optical communications were demanding better de‐ tectors to enlarge their use, other photodiodes were developed in this spectral region of great interest. Since no other single element semiconductor was possible, semiconductor hetero-junctions were developed. A hetero-junction is a junction formed between two semi‐ conductors with different band-gaps. Of course building such devices is not straightforward since the lattice parameters have to be matched, but this is not the subject of this chapter and many good references may be found in literature [17].

The group known as III-V hetero-structures has yield different photodiodes in the near IR range, particularly those based on InP/InGaAs has yield very good devices for the spectral range covered by germanium photodiodes. This hetero-structure has got two junctions in fact. The InGaAs material, having a lower gap, is kept in between two layers on InPwhose gap is bigger and hence transparent to the wavelength region used in optical communica‐ tions: the nondispersion wavelength (1.3μm) and the loss minimum wavelength (1.55μm). The radiometric characteristics of these InP-based photodetectors are superior to those of conventional photodiodes composed of elemental Germanium. Because of that they have re‐ placed germanium in almost every application.

and and germanium photodiode 12) formed an image of the monochromator's exit slit on the sensitive surfaces of photodiodes. The angle of incidence was equal to 7.4 º which was

The measurement method consists in comparing the response from a germanium photo‐ diode to the radiation reflected by the InGaAs/InP photodiode with the response from an

aluminum standard mirror whose reflectance is measured as in [21], so that [20]:

( ) () () ( ) *p*

l

l

*m*

mm in diameter and the other part had a quadratic active area of 8 mm x 8 mm.

*I I*

*m*

= (6)

Photodiodes as Optical Radiation Measurement Standards

http://dx.doi.org/10.5772/51462

181

 r l

the InGaAs/InP, *I m (λ)*is the response to the light reflected by the mirror, and ρm(λ) is the reflectance of a standard mirror. With this method the reflectance of photodiodes from dif‐ ferent manufacturers hasbeen measured. One part of detectors had a round active area of 5

The polarization degree of light at the output the monochromator was different with vary‐ ing the wavelength.The figures 5and 6 illustrate spectral dependences of the reflectance, which had been obtained from photodetectors belonging to three different manufacturers. Two types (photodiodes 1 and 4 and photodiodes 2 and 5) are 5 mm in diameter sensitive

accepted as the normal incidence in this train of measurements.

**Figure 4.** Experimental set-up for measuring the reflectance InGaAs/InP photodiodes

rl

Here,*I p (λ)* is the response to the light reflected by

**9. Analysis of Reflectance of InP Photodiodes**

By using a hetero-structure, which hadn't been used in group IV elemental semiconductors such as Si and Ge, new concepts and new designs for high performance photodetectors have been developed.For example, the absorption region for a specific spectral range can be con‐ fined to a limited inner layer, avoiding typical high recombination rates of charge carriers at the first interfaceof the photodiode and getting a higher internal quantum efficiency.

Recently InGaAs/InP avalanche photodiodes (APDs) with a SAM (separation of absorption and multiplication) configuration have become commercially available. The SAM configura‐ tion is thought to be necessary for high performance APDs utilizing long wavelengths.

InGaAs/InPphotodetectors are used for maintaining the scale of spectral responsitivityup to 1.7 μm in many laboratories [17, 19].In addition they are exploited in instruments for meas‐ uring optical radiation within the near infrared (NIR) range (800 nm -1600 nm). From this point of view, these photodiodes are like other and their response is given by equations (1) and (2). Therefore to know their reflectance and internal quantum efficiency is the key for defining the spectral responsivity scale in this range.

Next experimental values for those properties measured in our laboratory for devices built by different manufacturers will be presented.


4.3 Power system protection

In the search for shorter downtimes and the maximization of the life time of the energy system equipment, it repeats itself to increasingly finer methods for analysis. In the recent years, we have begun to analyze the protections of voltage transformers (TT) and current transformers (CT) by WT [27]. This was done previously in the use of the Fourier Transform (FFT) and the current protections of the internal fault current. Refs. [28–31] study the differentiation of these currents by theoretical methods. This means that the test in the field is not done but the results of the simulations give positive results, an exception of [31] where the methods are applied to a test TT. For the development of differential protections, [30, 32–34] analyze the transients and extract the predominant signal from the internal fault; the method has been tested with different faults and an efficient algorithm for online analysis has been obtained. In [33–41], WT is used for fault diagnostic and transient event identification in transformer operation.

There has been a great effort in different works to evaluate the different mother wavelet. Thus, [33, 34] present a comprehensive analysis involving an important number of wavelets to prove the efficiency in power transformer protection.

Another important part is between disruptive currents and fault currents in the earth, where the results were analyzed with computer programs [42, 43].

The bus zone protection scheme is considered for the detection of transient current in [44]. In the electric machine area, [45] proposed the use of the WT for fault diagnostic using current signal. The transmission line fault detection with WT in the presence of wind power generation is studied in [46, 47] approach, a study on fault detection in compensated transmission line (TCSC technology). In [48], wavelet analysis is used for fault detection in hybrid energy source.

## 4.4 Power quality

but also isolate them by frequency bands for their study, performing a multiresolution analysis. An important study is the filtering of noise in PD signals. In this sense, [15, 16] propose the recognition and categorization of PDs, for the study of

method in preestablished nodes to obtain the plant model to measure at

In [15], an adaptive filter is used to obtain PD without noise or interference for online studies. In [16], it is posed by means of a sophisticated equipment to obtain the currents and through WT to filter the PD and to be able to carry out its later study. If we follow the line of online monitoring, it can be seen in [17] that using a high-frequency transducer, the PD can be extracted to obtain analysis in transformers in service. We talked about how to get them and how to remove the noise in the signals, we just need to locate them. Ref. [18] proposes a PD injection

This section could be assembled considering different places of application of the WT, from generation to service transformers. In the generation, [19] shows us a study in the transients of the generation turbines where they perform an exhaustive analysis using a wavelet neural network to obtain the output values to adjust the

Works [20–22] propose the use of WT for applications in high voltage lines (EHV) and the power system. In [20], WT used for the study of the electric field in the conductors can obtain the waveform of the current and voltage that facilitates the study of faults with which a filter for the study of harmonics can be designed. In [21], using the entropy energy, it is possible to obtain parameters of systems that change with certain sensitivity and design a protection that can reduce the capacitive effects in the bars and in the high-frequency traps. Ref. [22] proposes to use several scales of different frequencies to decompose the harmonics for the detection, localization, and segmentation of them. With this, we can estimate the energy and overvoltage caused and discern between impulsive and oscillatory transients. Ref. [23] presents an analysis on which is the best wavelet mother for the measurement of harmonics in electrical systems. Ref. [24] proposes an empirical wavelet transform for harmonic detector under dynamism conditions of the system. Ref. [25] presents a method for detecting and classifying faults in transmission lines by

transformer failures.

Wavelet Transform and Complexity

Figure 3.

separate points.

4.2 Transient in electrical system

Wavelet publication percentage in different power system areas.

turbine and obtain a correct operation.

combining DWT and neural networks.

84

With the increase of the use of electronic equipment, it has become a necessity to study the quality of energy. The loads, having a stationary or non-stationary state, are no longer easily analyzed, so we resort to mathematical tools capable of classifying and characterizing these states. In this network, transient disturbance occurring in the network can be classified as voltage drops, voltage increases, momentary interruptions, harmonics, and transients, among others.

The main topics of study are the harmonics; these are present in the waves and are common to see in the electrical networks, and so the first step would be to identify them and isolate their behavior in order to eliminate these disturbances. Ref. [49–51], using WPT, perform a method in which the fundamental harmonic and higher order harmonics can be extracted, which is a method applicable to energy networks for monitoring them. For the same application [52], they have formulated using CWT, an algorithm used to identify the variations of frequency, harmonics, sub harmonics, and inter harmonics.

A practical application of the CWT is the real-time monitoring of voltage and current signals for the rapid detection and elimination of transient events that may worsen the quality of the electric service. Previously, the first subject of study in terms of energy quality was established, but this is only a small part of the faults found in the energy system. Faults must be identified in order to perform an efficient analysis and be able to act on them as soon as they occur.

In the papers presented in [42, 53–61], their main theme coincides and is to classify the faults that can be obtained from the analysis of the voltage wave through WT. Broadly speaking, it can be highlighted that they obtain the range of frequency, amplitude, time of action, waveform, etc. Although their methods differ in the application of the WT, the essence of the study is the same. One step beyond performing fault classification studies is to achieve a practical application for the inservice power network. In [62], it implements a DSP for the continuous study of energy. Ref. [63] uses an FPGA for continuous analysis of system disturbances. In [42], through a wavelet neural network and a self-organizing arrangement system, it obtains automatic equipment for the detection and suppression of multiple faults in the network.

5. Conclusion

systems analysis.

situations.

Author details

87

Wavelet transform is a powerful signal processing tool that transforms a timedomain waveform into time-frequency domain and estimates the signal in the time and frequency domains simultaneously. So, it is mostly used in electric power

This chapter carries out an approach on the WT application in EPS in order to facilitate the search for information in this area. Therefore, a classification of the different fields of EPS applications was made. A summary description for each WT application area is presented with the main objective of showing the applications of

The works analyzed show that the Daubechies family was used in most of the applications in power systems analysis, especially in protection area. However, the type of mother wavelet and the decomposition level number may be changed and

The use of WT together with artificial intelligence tools (neural networks, fuzzy logic, genetic algorithms, etc.) was presented as a promising methodology to diag-

Most of the works analyzed results of computational simulations. It is expected

that in the short term, the functionality of WT it is will comprobed in real

Mario Orlando Oliveira\*, José Horacio Reversat and Lucas Alberto Reynoso Research and Development Laboratory in Electric Energy – LIDEE, Faculty of Engineering, National University of Misiones – UNaM, Oberá, Misiones, Argentina

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to<EMAIL_ADDRESS>
provided the original work is properly cited.

this tool in the resolution of typical problems of the energy system.

Wavelet Transform Analysis to Applications in Electric Power Systems

DOI: http://dx.doi.org/10.5772/intechopen.85274

therefore may not be generalized to all the cases.

nose faults in electrical systems.

Other areas of power quality are studied using the WT characteristic. In [64, 65], the power quality events are characterized and classified using wavelet transformation. The power quality disturbance detection in grid-connected wind energy system is development with wavelet and S-transform. In [66] is presented a comparative analysis of power quality event using wavelet for real time implementation and [67] tested measurement system to electric energy quality together digital signal processor.

The voltage variation is a usual problem in electric system which affects the quality power. Ref. [68] addresses this problem from distributed energy resources.

### 4.5 Load forecasting

This analysis is the key to a correct distribution of energy in the electricity grid. Basically, a prediction is made of how the loads will behave in short- or mediumterm horizons. In this sense, the behavior of the load can refer to disconnections of large equipment, circuits that have transients in start, devices with low power factor, etc. This analysis can be done through WT and some complement to make the prediction.

We have cases like [69] that use a linear correlation for the load forecast. This is a more conventional method compared to the other two. In recent years, there is much talk of NN and machine learning to such a point that [70–79] use machine learning to train a WT-based neural network. The load forecasting in the short-term used WT theory is presented in [80, 81]. Thus, it can be observed that this application is widely studied.

From another point of view, we have a prediction system based on fuzzy logic in [82], and finally, in the current year, a neural network with fuzzy logic based on WT is launched for the short-term study, which may be the foot to what is coming to the future.

### 4.6 Power system measurements

Mainly, the WT is used in power systems and RMS measurements, both voltage and current. As for the measurement systems of active, reactive, or apparent power, a decomposition and classification of those waves present in the fundamental are achieved. In [83], it analyzes how the variations of the loads influence the tension, as much as it falls as in descents or in blinking. Then in [23], it approximates the RMS value of the harmonics present in the voltage and current waves by means of statistics; with this purpose, the improvement of harmonic detection and measurement systems is sought. In [84], a method for determination and correction of measurement anomaly based in WT is proposed.


3.2 Generation of curved surface plasmon modes

The previous statistical description will be employed for the synthesis of surface plasmonic modes. The expression for the electric field of an elementary surface plasmonic mode propagating along the z-axis is given by

$$E(\mathbf{x}, z) = \left(\hat{i}a + \hat{k}b\right) \exp\left\{-a\mathbf{x}\right\} \exp\left\{i\beta\mathbf{z}\right\},\tag{18}$$

˜ °1=2 where β ¼ w ε1ε2 ¼ ξ þ iη is the dispersion relation function and ε1, ε2 repre- c ε1þε2 sent the permittivity of the dielectric and metal, respectively. Rotating the reference system along the x-axis, the elementary surface plasmon mode acquires the form

$$E(\mathbf{x}, \mathbf{z}) = \left(\hat{i}a + \hat{j}b\sin\theta + \hat{k}b\cos\theta\right) \times \exp\left\{-a\_1\mathbf{x}\right\} \exp\left\{i\beta(\mathbf{z}\cos\theta + y\sin\theta)\right\}.\tag{19}$$

Using the functional relation given by Eq. (17), the expression for the curved plasmonic mode is given by

$$E(\mathbf{x}, \mathbf{y}) = \left(\hat{i}a + \hat{j}b\sin\theta + \hat{k}b\cos\theta\right) \times \exp\left\{-a\mathbf{x}\right\} \exp\left\{i\theta(\mathbf{y}^a\cos\theta + y\sin\theta)\right\}.\tag{20}$$

By means of the Maxwell equations, we can obtain the expression for the magnetic field and the energy flux given by the Poynting vector.

Synthesis of Curved Surface Plasmon Fields through Thin Metal Films in a Tandem Array DOI: http://dx.doi.org/10.5772/intechopen.81931

For the experimental setup, we propose to illuminate a thin flat Au film (thickness �20–40 nm) with a correlated speckle pattern as shown in Figure 4. The illumination consists in two speckle patterns: each one is visualized as a set of circular motes randomly distributed following a Gaussian probability density function. The wavelength is λ ¼ 1550 nm. The geometrical parameters are agreeing with those reported in [8]. The correlation curve corresponds to the surface plasmonic mode given by Eq. (20). Notably, the statistical properties of the speckle pattern are transferred to the metal surface as the plasmonic mode propagating along the correlation trajectory. In order to allow the generation of a long-range curved plasmonic mode, the correlation length must be less than 2μ to guarantee resonance effects [9, 10]; this can be controlled with the roughness parameters of the surface implemented to generate the speckle pattern avoiding the power decay along the correlation trajectory. The experimental setup is sketched in Figure 5.

Figure 5. Masked metal surface: The typical wavelength is IR.

The analysis presented can be extended to other plasmonic configurations which are presented in the following section.