The role of the Rashba coupling in spin current of monolayer gapped graphene

In the current work we have investigated the influence of the Rashba spin-orbit coupling on spin-current of a single layer gapped graphene. It was shown that the Rashba coupling has a considerable role in generation of the spin-current of vertical spins in mono-layer graphene. The behavior of the spin-current is determined by density of impurities. It was also shown that the spin-current of the system could increase by increasing the Rashba coupling strength and band-gap of the graphene and the sign of the spin-current could be controlled by the direction of the current-driving electric field

Mycoplasma Agassizii Infections in the Desert Tortoise (Gopherus Agassizii)

ABSTRACT Mycoplasma agassizii is a cause of upper respiratory tract disease in the threatened desert tortoise (Gopherus agassizii) of the Southwestern United States. Two technical challenges have impeded critical microbiological studies of this microorganism. First, its small size (<300 nm) limits the use of light microscopy for cell counting. Second, its slow growth in broth and agar cultures impedes colony counting. Our aim was to develop a rapid and sensitive flow cytometric method using a vital fluorescent dye to enumerate viable M. agassizii cells. We discovered that the non-fluorescent molecule 5-carboxyfluorescein diacetate acetoxymethyl ester penetrates M. agassizii cell membranes and is converted in the cytoplasm to the fluorescent molecule 5-carboxyfluorescein by the action of intracellular esterases. Labeled mycoplasma cells can be easily detected by flow cytometry, and cultures with fewer than 100 viable mycoplasma cells µl-1 can be labeled and counted in less than 1 h. Experiments using temperature-induced cell death demonstrated that this procedure labels only viable M. agassizii cells. This technique should facilitate basic immunological, biochemical, and pharmacological studies of this desert tortoise pathogen which may lead to new diagnostic and therapeutic methods. To facilitate seroepidemiologic studies of infectious diseases caused by microorganisms like M. agassizii, isotype-specific antibody reagents are needed. Our goal was to prepare isotype-specific rabbit polyclonal antibodies to desert tortoise IgM and IgY. A 50% saturated ammonium sulfate precipitate of desert tortoise serum was fractionated by Sephacryl A-300 gel filtration chromatography and IgM-rich and IgY-rich fractions were collected. SDS-PAGE confirmed the molecular weights of the heavy chains of tortoise IgM and IgY to be 71 kD and 68 kD respectively. Rabbits immunized with these separate fractions produced high titer sera that cross-reacted slightly with the opposite heavy chain and strongly with the conserved 22 kD light chain. To make heavy chain isotype-specific reagents, the immunoglobulin fraction of each antiserum was cross-absorbed using polystyrene microspheres coated with the opposite isotype. SDS-PAGE and Western blots confirmed the heavy chain specificity of the cross-absorbed antibodies. These high avidity rabbit polyclonal antibody reagents were used in ELISA and Western blots to document the primary and secondary isotype-specific antibody responses to M. agassizii infection and ovalbumin immunizations in desert tortoises. The availability of rabbit polyclonal antibodies to desert tortoise IgM and IgY will allow more detailed studies of the humoral immune response of the desert tortoise to microbial pathogen

Transient Stability Enhancement of Wind Farms Using Power Electronics and FACTS Controllers

Nowadays, it is well-understood that the burning of fossil fuels in electric power station has a significant influence on the global climate due to greenhouse gases. In many countries, the use of cost-effective and reliable low-carbon electricity energy sources is becoming an important energy policy. Among different kinds of clean energy resources- such as solar power, hydro-power, ocean wave power and so on, wind power is the fastest-growing form of renewable energy at the present time. Moreover, adjustable speed generator wind turbines (ASGWT) has key advantages over the fixed-speed generator wind turbines (FSGWT) in terms of less mechanical stress, improved power quality, high system efficiency, and reduced acoustic noise. One important class of ASGWT is the doubly-fed induction generator (DFIG), which has gained a significant attention of the electric power industry due to their advantages over the other class of ASGWT, i.e. fully rated converter-based wind turbines. Because of increased integration of DFIG-based wind farms into electric power grids, it is necessary to transmit the generated power from wind farms to the existing grids via transmission networks without congestion. Series capacitive compensation of DFIG-based wind farm is an economical way to increase the power transfer capability of the transmission line connecting wind farm to the grid. For example, a study performed by ABB reveals that increasing the power transfer capability of an existing transmission line from 1300 MW to 2000 MW using series compensation is 90% less than the cost of building a new transmission line. However, a factor hindering the extensive use of series capacitive compensation is the potential risk of sub- synchronous resonance (SSR). The SSR is a condition where the wind farm exchanges energy with the electric network, to which it is connected, at one or more natural frequencies of the electric or mechanical part of the combined system, comprising the wind farm and the network, and the frequency of the exchanged energy is below the fundamental frequency of the system. This phenomenon may cause severe damage in the wind farm, if not prevented. Therefore, this dissertation deals with the SSR phenomena in a capacitive series compensated wind farm. A DFIG-based wind farm, which is connected to a series compensated transmission line, is considered as a case study. The small-signal stability analysis of the system is presented, and the eigenvalues of the system are obtained. Using both modal analysis and time-domain simulation, it is shown that the system is potentially unstable due to the SSR mode. Then, three different possibilities for the addition of SSR damping controller (SSRDC) are investigated. The SSRDC can be added to (1) gate-controlled series capacitor (GCSC), (2) thyristor-controlled series capacitor (TCSC), or (3) DFIG rotor-side converter (RSC) and grid-side converter (GSC) controllers. The first and second cases are related to the series flexible AC transmission systems (FACTS) family, and the third case uses the DFIG back-to-back converters to damp the SSR. The SSRDC is designed using residue-based analysis and root locus diagrams. Using residue-based analysis, the optimal input control signal (ICS) to the SSRDC is identified that can damp the SSR mode without destabilizing other modes, and using root-locus analysis, the required gain for the SSRDC is determined. Moreover, two methods are discussed in order to estimate the optimum input signal to the SSRDC, without measuring it directly. In this dissertation, MATLAB/Simulink is used as a tool for modeling and design of the SSRDC, and PSCAD/EMTDC is used to perform time-domain simulation in order to verify the design process

Application of Reduced Differential Transform Method for Solving Nonlinear Reaction-Diffusion-Convection Problems

In this paper, Reduced differential transform method is presented for solving nonlinear reactiondiffusion- convection initial value problems. The methodology with some known techniques shows that the present approach is simple and effective.To show the efficiency of the present method, four interesting examples is given

Anatomical and histological study of molar salivary gland in domestic cat

Summary The gross and microscopic anatomy of the molar salivary gland of the domestic cat was studied. In this research, five pair of molar glands from five male adult cats were used. In cat, the molar gland was elongated rectangle shape and was located obliquely in the submucosal fossa of the inferior lip, near the oral commissure. The dorsal border of the molar gland was attached to the masseter muscle and posterior facial nerve. The ventral border was located in the angle of the anterior and transverse facial veins near the buccal part of the buccinator muscle. The caudal end of the gland neighboring the anterior facial vein and cranial end was close to the transverse jugular vein. The mean length and width of the left gland were 11.5 ± 0.3 mm and 3.4 ± 0.3 mm, respectively. The mean length and width of the right gland were 9.2 ± 0.8 mm and 4.1 ± 0.8 mm, respectively. The mean length of the left gland was larger than the right and the difference was significant (P&lt;0.001). In the histological findings the molar gland was surrounded with a dens irregular connective tissue capsule. The septa of the connective tissue from the capsule extended into the gland, dividing the organ into lobes and lobules. The secretory cells made up seromucous units and the mucous cells were predominant. The cells were arranged as compound tubuloacinar type. Most of the tubular units were long and branched, and there were no intercalated or striated ducts

Comparison of psychological and sexual consequences of tubal ligation and other contraceptive methods in women referring to Shahrekord health centers in 2005-2007, Iran

Background and aim: Tubal ligation (TL) is a popular, safe, reversible and effective method of birth control. However it has some side effects. In this study, psychological and sexual consequences of TL and other contraceptive methods in women who had referred to Shahrekord health centers in a period between 2005 and 2007 were compared. Methods: In this descriptive and analytical study a total of 384 women (174 in TL group and 210 in other contraceptive methods group) were selected by simple sampling method. Data were collected by interview and demographic questionnaires, GHQ-28 and sexual disorders questionnaires (DSM-IV) at the beginning of the study and six months later. Data were analyzed and evaluated by Mann Whitney U, McNemar, t-student and Chi-square (χ2) tests. Results: Psychological disorder in TL group was 31.3% at the beginning of the study and increased to 39.7% at the end of the study (P<0.05). Sexual disorders in TL group was 18.4% and 28.7% at the beginning and end of the study respectively (P<0.01). There was no significant difference in psychological and sexual disorders for the second group. Conclusion: TL group shows higher psychological and sexual disorders compared to the other contraceptive method groups. We suggest that those women selecting TL method, be informed the negative effects of it

The effect of date palm tissue and aggregation pheromone on attraction and trapping of Red Palm Weevil, Rhynchophorus ferrugineus Oliv. (Col.: Dryophthoridae)

Red Palm Weevil (RPW), Rhynchophorus ferrugineus Oliv. (Col.: Dryophthoridae), is a key pest of date palm in Asia, North Africa and Spain. A field study was conducted in south eastern Iran to find the effect of odor sources in traps on RPW behavior. This study consisted of four experiments; each included four treatments (odor sources) and eight replications. Each experiment was repeated 4 times (i.e. four different distances between odor sources (treatments) were considered: 0, 0.5, 2 and 5 meters). In each treatment, two traps were used. The treatments were as follows: 1) one trap included two pheromones and the other trap included two pieces of plant tissue, 2) both traps included one pheromone along with one piece of plant tissue, 3) both traps included one pheromone, and 4) both traps included one piece of plant tissue. Overall, much less RPWs were caught in the traps of treatments 3 and 4 (baited with only the pheromone or the plant bait) than in the traps of treatments 1 and 2 (baited with pheromone and plant tissue) evidencing the phenomenon of synergy, previously reported. The Results of analysis of variance of total catch of traps, at all between-trap distances indicated that there was significant difference among treatments. In all experiments, traps that contained just palm tissue had the least catch rate. The RPW distinguished pheromone from plant odor when both sources were separated by less than 5 m. At distances of 5 m, attractancy of plant odor was similar to pheromone attractancy. Our results suggest that each of the chemical cues probably induce a different behavioral process. Probably, pheromone would attract RPWs from a distance, making them fly towards the pheromone sources (traps) while the plant odor would arrest flight and induce landing and local search by walking for palm tissue, resulting in entry into traps

Comparison of the Effect of Peer-led Education and Education by the Healthcare Personnel on Awareness, Attitude and Performance of Lettered People toward Organ Donation

BACKGROUND AND OBJECTIVE: Lack of donation is one of the major limitations of organ transplantation. Promoting organ donation requires increased awareness and creation of a positive attitude through training in specific ways. The purpose of this study was to compare the effect of peer-led education and education by healthcare personnel on awareness, attitude and performance of lettered people in regard with organ donation. METHODS: This case-control clinical trial was performed on 120 lettered people who were randomly assigned to three groups of 40, including peer-led, healthcare personnel and control groups. The two intervention groups underwent training sessions. Before and after the intervention, the data were collected and compared using questionnaires in three groups in three areas of awareness, attitude and performance. FINDINGS: Most of the lettered people (58.33%) were female. 61.66% had a bachelor's degree and 60.83% were teachers at elementary school. There was a significant difference in the mean scores of awareness, attitude and performance toward organ donation in the two intervention groups before the intervention (in peer-led group were 11.52 ± 2.12, 92.05 ± 10.24, and 1.87 ± 1.42 and in healthcare group were 11.30 ± 3.00, 90.73 ± 10.92, and 1.38 ± 1.29, respectively) and after the intervention (in peer-led group were 15.47 ± 1.13, 98.78 ± 5.70, and 3.53 ± 0.50 and in healthcare group were 15.13 ± 1.49, 96.95 ± 5.52, and 3.05 ± 0.81, respectively) ( P < 0.05). The mean score of attitude and performance of the lettered people in the peer-led group was significantly higher than the other groups (P < 0.05). CONCLUSION: The results of the study showed that peer-led education is a more effective method than education by healthcare personnel to promote and institutionalize organ donation

Morphological study of the midbrain tectum in ostrich (Struthio camelus) embryo

In this study the morphological features of the optic tectum in ostrich embryo were studied macro-scopically and microscopically. After gross anatomical study, fixed specimens of the optic lobes in 30th, 36th and 40th embryonic days were processed for paraffin sections. Sections were stained by Harris haematoxylin and eosin (H&E), Luxol Fast Blue/Cresyl Echt Violet and Malory PTAH dyes. The optic lobes had large volumes even on the 30th embryonic day and increased proportionally to age. The optic lobe consisted of two parts: gray matter (outer) and white matter (inner). The first ex-ternal layer of the optic lobe e.g. molecular layer consisted of neural fibres, neuroglia and scarce small neurons. The most common appearance of the optic lobes was characterised by small to medium-sized neurons (rounded to pyramid-shaped with large and pale nucleus consistong of obvious nucleoli ar-ranged in three layers whose thickness increased in the deeper one) supported by neuroglia. Larger size neurons and occasionally multipolar neurons were presented in the interior compared with these layers. The lateral mesencephalic nucleus was detectable in the optic lobe base even on 30th embryonic day and was composed of few multipolar neurons supported by neuroglia. The tectal ventricles were lined with simple cuboidal ciliated ependymal cells in the embryonic period. As embryonic age increased, the ratio of tectal ventricle volume to its thickness decreased. Special stainings showed that Nissl bodies and myelin fibres, also glial fibres were available from the 30th embryonic day and that their density, especially myelin fibres density, increased with age

Impact of melatonin supplementation in the rat spermatogenesis subjected to forced swimming exercise

Oxygen consumption increases many times during exercise, which can increase reactive oxygen species. It negatively affects fertility in male athletes. Melatonin is exerting a regulatory role at different levels of the hypothalamic-pituitary-gonadal axis. However, there is no evidence that the protective effects of melatonin persist after long duration exercise on the spermatogenesis. Therefore, this study was conducted to examine the impacts of melatonin on the testis following the administration of swimming exercise. Rats were separated into five different groups, including Control, sham M: received the solvent of melatonin, M: received melatonin, S: the exercise protocol, MS: received melatonin and the exercise protocol. After 8weeks, animals were scarified and antioxidant enzymes levels of testes, spermatogenic cells apoptosis and sperm quality were measured. Swimming decreased all parameters of spermatozoa. Nevertheless, melatonin could significantly improve the progressive motility of spermatozoa in MS rats. Swimming caused an increased apoptosis of S group and decreased all antioxidant enzymes. Melatonin could drastically reduce apoptosis and increased these enzymes. Therefore, melatonin seems to induce the production of antioxidant enzymes of testicular tissues and diminish the extent of apoptotic changes caused by forced exercise on the testis, which can, in turn, ameliorate the sperm parameters