Perfusion Fixation With Glutaraldehyde and Post-Fixation With Osmium Tetroxide for Electron Microscopy

The conductivity of cerebral cortex drops during perfusion with glutaraldehyde in 5 min to about 60% of the original value, to remain unchanged during the subsequent 10-15 min of perfusion. Circulatory arrest causes a similar drop in the tissue conductivity. Perfusion of asphyxiated tissue with glutaraldehyde does not produce additional major changes in the conductivity. Perfusion of the cortex with an osmium tetroxide solution causes an initial drop in conductivity. However, after about 3 min this trend is reversed and the conductivity increases again to close to the pre-perfusion value. Perfusion of asphyxiated cortex with OsO4 causes a marked increase of the conductivity. So does perfusion with an OsO4 solution of tissue previously treated with glutaraldehyde. One interpretation of these impedance changes is that glutaraldehyde perfusion causes, like asphyxiation, a transport of extracellular material into the intracellular compartment and that during OsO4 perfusion an extracellular space is again created. This possibility is supported by electron micrographs made of this material. Cerebral cortex perfused with glutaraldehyde and post-fixed with OsO4 shows electron-transparent dendritic elements and to a lesser extent pre-synaptic terminals, which seem to be swollen. When the cortex is flooded with a salt solution during glutaraldehyde perfusion the dendrites exhibit ballooning in the surface layer of the cortex, suggesting that the fluid on the cortex participates in the swelling. The tissue elements in the glutaraldehyde-perfused and OsO4 post-fixed cortex are separated by narrow extracellular spaces. The latter may have been produced by the OsO4 perfusion as is suggested by a comparison of micrographs prepared by freeze substitution (which tends to preserve the water distribution) of glutaraldehyde-perfused but not post-fixed cortex with micrographs of cortex treated with OsO4 after the glutaraldehyde perfusion. In accordance with the conductivity changes, the former micrographs showed very little extracellular space, and in many places tight junctions, whereas the latter showed clefts between the tissue elements

Fault tolerant control of multi-rotor unmanned aerial vehicles using sliding mode based schemes

This thesis investigates fault-tolerant control (FTC) for the specific application of small multirotor unmanned aerial vehicles (Unmanned Aerial Vehicle (UAV)s). The fault-tolerant controllers in this thesis are based on the combination of sliding mode control with control allocation where the control signals are distributed based on motors' health level. This alleviates the need to reconfigure the overall structure of the controllers. The thesis considered both the over actuated (sufficient redundancy) and under-actuated UAVs. Three multirotor UAVs have been considered in this thesis which includes a quadrotor (4 rotors), an Octocopter (8 rotors) and a spherical UAV. The non-linear mathematical models for each of the UAVs are presented. One of the main contributions of this thesis is the hardware implementation of the sliding mode Fault Tolerant Control (FTC) scheme on an open-source autopilot microcontroller called Pixhawk for a quadrotor UAV. The controller was developed in Simulink and implemented on the microcontroller using the Matlab/Simulink support packages. A gimbal- based test rig was developed and built to offer a safe test bed for testing control designs. Actual flight tests were done which showed sound responses during fault-free and faulty scenarios. This work represents one of successful implementation work of sliding mode FTC in the literature. Another key contribution of this thesis is the development of the mathematical model of a unique spherical UAV with highly redundant control inputs. The use of novel 8 flaps and 2 rotors configuration of the spherical UAV considered in this thesis provides a unique fault tolerant capability, especially when combined with the sliding mode-based FTC scheme. A key development in the later chapters of the thesis considers fault-tolerant control strategy when no redundancy is available. Unlike many works which consider FTC on quadrotors in the literature (which can only handle faults), the proposed schemes in the later chapters also include cases when failures also occur converting the system to an under actuated system. In one chapter, a bespoke Linear Parameter Varying (LPV) based controller is developed for a reduced attitude dynamics system by exploiting non-standard equation of motions which relates to position acceleration and load factor dynamics. This is unique as compared to the typical Euler angle control (roll, pitch and yaw angle control). In the last chapter, a fault-tolerant control scheme which can handle both the over and under actuated system is presented. The scheme considers an octocopter and can be used in fault-free, faulty and failure conditions up to two remaining motors. The scheme exploits the differential flatness property, another unique property of multirotor UAVs. This allows both inner loop and outer loop controller to be designed using sliding mode (as opposed to many sliding mode FTC in the literature, which only considers sliding mode for the inner loop control)

Phenotypic and Genotypic Trends for Some Economic Traits in Egyptian Buffaloes

A total of 2763 lactation records of Egyptian buffaloes, sired by 147 bulls, were collected from Mahalla Mousa Farm, Kafer El sheihk Government. Traits studied are milk production (MP), lactation length (LL) and age of heifers at calving (AHC). Effects of period and month of calving, lactation order and heifers at calving were studied as main effects , beside bull, buffaloes within bulls and errors were studied as random effects.. Also, Animal mode was used to estimate genotypic parameter, transmitting ability, phenotypic and genotypic trends for above traits studied. Least squares analysis of variance (Table 2) show a significant effects of year of calving and month of calving and lactation order on MP, LL and AHC. Linear and quadratic regression coefficients of MP and LL on AHC had also a significant effect. Sires and buffaloes within sires had a significant effect on MP, LL and AHC. Estimates of (h2) were 0.28, 0.20 and 0.10, for MP, LL and AHC respectively. Genotypic correlations between MP and each of LL and AHC were 0.76 and -0.36, respectively. Genotypic correlation between MP and AHC was -0.30. Phenotypic correlation between MP and both of LL and AHC were 0.80 and -0.90, respectively and phenotypic correlation between LL and AHC was -0.40. Predicted transmitting ability from buffaloes ranged from -774 to 933 kg for MP from – 60 to 101 d for LL and from – 4 to 8 mo., for AHC. Predicted sire transmitting ability for MP ranged from – 408 to 535 kg, for LL ranged from -27 to 29 d and for AHC ranged from -2 to 5 mo., Expected dam transmitting ability ranged from -388 to 365 kg for MP, from – 30 to 23 d for LL from - 2 to 2 mo., for AHC. Annual phenotypic and genetic trend for milk production calving was positive and significant. While, annual genotypic change for lactation length and age of heifers at calving were negative and significant

Iyengar Yoga Increases Cardiac Parasympathetic Nervous Modulation Among Healthy Yoga Practitioners

Relaxation techniques are established in managing of cardiac patients during rehabilitation aiming to reduce future adverse cardiac events. It has been hypothesized that relaxation-training programs may significantly improve cardiac autonomic nervous tone. However, this has not been proven for all available relaxation techniques. We tested this assumption by investigating cardiac vagal modulation during yoga.We examined 11 healthy yoga practitioners (7 women and 4 men, mean age: 43 ± 11; range: 26–58 years). Each individual was subjected to training units of 90 min once a week over five successive weeks. During two sessions, they practiced a yoga program developed for cardiac patients by B.K.S. Iyengar. On three sessions, they practiced a placebo program of relaxation. On each training day they underwent ambulatory 24 h Holter monitoring. The group of yoga practitioners was compared to a matched group of healthy individuals not practicing any relaxation techniques. Parameters of heart rate variability (HRV) were determined hourly by a blinded observer. Mean RR interval (interval between two R-waves of the ECG) was significantly higher during the time of yoga intervention compared to placebo and to control (P < 0.001 for both). The increase in HRV parameters was significantly higher during yoga exercise than during placebo and control especially for the parameters associated with vagal tone, i.e. mean standard deviation of NN (Normal Beat to Normal Beat of the ECG) intervals for all 5-min intervals (SDNNi, P < 0.001 for both) and root mean square successive difference (rMSSD, P < 0.01 for both). In conclusion, relaxation by yoga training is associated with a significant increase of cardiac vagal modulation. Since this method is easy to apply with no side effects, it could be a suitable intervention in cardiac rehabilitation programs

The protective role of melatonin on L-arginine-induced acute pancreatitis in adult male albino rats

Background: Acute pancreatitis (AP) is an inflammatory disease that has an increasing incidence worldwide. AP is associated with high morbidity and mortality rates ranging 15–40% in its severe form. Oxidative stress plays an important role in pancreatic acinar cell injury in case of AP. Melatonin (Mel) is proven to have both antioxidant and anti-inflammatory effects. The aim of the work was to investigate the protective role of Mel against L-arginine (L-arg)-induced AP in adult male albino rats. Materials and methods: Thirty-six adult male albino rats were used in this study. Animals were divided into four groups; Control group (Group A; n = 6), Mel group (Group B; n = 6), L-arg group (Group C; n = 12) receiving two doses of L-arg injection with 1 h interval in-between, and L-arg+Mel group (Group D; n = 12) receiving Mel 1 h after each L-arg injection. 24 h after the second L-arg injection, the serum levels of amylase (AM), lipase (LP), interleukin-6 (IL-6) and tumour necrotic factor-alpha (TNF-α) were determined. Then, pancreatic specimens were processed for histological and immunohistochemical staining with vascular endothelial growth factor (VEGF) and the area percentage of VEGF and collagen content were measured by digital image analysis. Results: Microscopic examination revealed that animals received L-arg only (Group C) showed loss of the pancreatic lobular architecture with marked fibrosis, acinar degeneration, inflammatory reaction and marked oedema with vascular congestion. Also, L-arg-induced AP caused a significant elevation of the serum levels of AM, LP, IL-6. All these histo-pathological and serological parameters were markedly improved by Mel administration. Conclusions: Melatonin exhibits strong therapeutic effects in the course of AP. Hence, the use of Mel as adjuvant treatment in AP is recommended.

A feasibility test of an online intervention to prevention dating violence in emerging adults

Dating violence in emerging adults is a significant problem and few prevention programs based on the developmental needs of this age group have been developed. Our research team developed an online dating violence prevention program called WISER (Writing to Improve Self-in-Relationships) for emerging adults. The program is based on narrative therapy principles and uses structured writing techniques. A single group pre-post feasibility test of WISER was conducted with 14 college women. WISER was demonstrated to be feasible and acceptable and to show promise as an effective program to decrease dating violence in this population

Flight evaluations of sliding mode fault tolerant controllers

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordThis paper considers the development of fault tolerant controllers (FTC) and their application to aerospace system. In particular, given the extensive and growing literature in this area, this paper focusses on methods where the schemes have been implemented and flight tested. One thread of the fault tolerant control literature has involved sliding mode controllers. This paper considers a specific class of sliding mode FTC which incorporates control allocation to exploit over-actuation (which is typically present in aerospace systems). The paper describes implementations of these ideas on a small quadrotor UAV and also piloted flight tests on a full-scale twin-engined aircraft

Channel Secondary Random Process for Robust Secret Key Generation

The broadcast nature of wireless communications imposes the risk of information leakage to adversarial users or unauthorized receivers. Therefore, information security between intended users remains a challenging issue. Most of the current physical layer security techniques exploit channel randomness as a common source between two legitimate nodes to extract a secret key. In this paper, we propose a new simple technique to generate the secret key. Specifically, we exploit the estimated channel to generate a secondary random process (SRP) that is common between the two legitimate nodes. We compare the estimated channel gain and phase to a preset threshold. The moving differences between the locations at which the estimated channel gain and phase exceed the threshold are the realization of our SRP. We simulate an orthogonal frequency division multiplexing (OFDM) system and show that our proposed technique provides a drastic improvement in the key bit mismatch rate (BMR) between the legitimate nodes when compared to the techniques that exploit the estimated channel gain or phase directly. In addition to that, the secret key generated through our technique is longer than that generated by conventional techniques

Yellow pea flour and protein isolate as sources of antioxidant peptides after simulated gastrointestinal digestion

Although peas are widely consumed legumes throughout the world, the bioactivity ofthe peptides released by the gastrointestinal digestion has not been sufficiently studiedso far. The objective of the present work was to evaluate the potential of floursand protein isolates obtained from two varieties of yellow peas as sources of antioxidantpeptides. Flours and protein isolates were prepared and submitted to a simulatedgastrointestinal digestion. Protein hydrolysis degree (TNBS method) andprotein solubility (in phosphate buffer saline, pH = 7.4) values were independent onthe starting material. Antioxidant activity measured by oxygen radical absorbancecapacity (ORAC) and hydroxyl radical averting capacity (HORAC) showed no differencesbetween varieties. A lower activity was registered for protein isolates withrespect to flours in the case of HORAC, which could be associated with a loss of moleculeswith molecular masses lower than 43 kDa in the protein isolates. A significantincrease in activities was evidenced by both methods after gastrointestinal digestion,except in the case of HORAC activity of flours. Digested from protein isolates presenteda greater ratio of molecules smaller than 1.4 kDa and a lower ratio of thoselarger than 6.5 kDa with respect to digested flours, according to electrophoresis andgel filtration chromatography studies. Results suggested that the presence of othercomponents or/and the initial state of proteins would affect proteolytic attack ofdigestive enzymes. Both, pea flours and protein isolates, present interesting potentialas antioxidants food ingredients.Fil: Cipollone, María Agustina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Tironi, Valeria Anahi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin