Search

In the age homogenous group of 13 healthy volunteers, we examined visual evoked potentials (VEP) visually evoked cognitive potentials (event-related potentials – ERP) and choice reaction time (CRT) five times during the day (from 10.00 a.m. up to midnight) to verify whether there are significant changes of the measured parameters of the cortical evoked potentials and CRT which might reflect the level of the mental fatigue. The electrophysiological testing was done with the use of a new portable VEP device named “VEPpeak” enabling to perform the examination outside standard labs in almost any conditions. It was found that the latency of ERP (P300 peak time) and CRT displayed significant prolongation toward midnight while VEP latency and all amplitudes did not change significantly. This pilot study supports our idea that the portable VEP device possibly might be used for the objective examination of mental fatigue that is needed in many situations. This should be confirmed in a larger study also including a comparison with non-electrophysiological fatigue testing.

Abstract An effective electroanalytical method was developed for the quantitative evaluation of fenitrothion pesticide. The electrochemically modified carbon paste electrode CPE was constructed by applying a safranine layer on its surface. Safranine monomer is easily oxidized. So, a safranine layer was applied via electropolymerization using cyclic voltammetry in (2 × 10–5 M) safranine buffered solution with phosphate buffer BPS at pH.6, potential window (− 1.6: + 2 V), scan rate 100 mV/s. The morphology of the modified electrode was characterized using SEM images. The electropolymerization process was characterized by observing the gradual increases of the peak current with the subsequent scanning cycles. This modified CPE electrode showed an obvious sensitivity by cyclic voltammetry towards the cathodic peak of the fenitrothion nitro group at approximately − 0.73V with good sensitivity by enhancing it to be approximately 10 times more sensitive than on a bare carbon paste electrode CPE. The number of cycles was optimized for the electropolymerization process to be 12 cycles. Where, the peak current at − 0.73 V was gradually enhanced until 12 cycles when it is obviously decreased before slightly increasing again. The reproducibility of the modified electrode was ensured by repeating the sweep cycles using LSV for determining the fenitrothion at 5 µM where it was found that the peak current was unchanged for 10 sweeps before it starts to drop gradually. LSV voltammetry at previously optimized conditions of the potential window (− 0.4: − 1 V), sweep rate 100 mV/s, phosphate buffer at pH.6 was used for the quantitative studies. Where, the pHs of the determining medium were varied from pH 5.5 to pH 8 using phosphate buffer. It was observed that the most identified peak current was at pH.6 which is then decreased gradually until it completely disappeared at pH 8. The optimal accumulation time by adsorption of 140 s for the fenitrothion pesticide was confirmed in the range of (20 s–170 s). Where, the peak current was increased gradually with time up to 140 s then a plateau with a constant response was observed. The developed method showed an excellent linearity range of (1 μM:15 μM) with R2 parameter equal to 0.99906. LOD and LOQ were calculated to be 0.1 μM, and 0.34 μM respectively. Satisfactory levels have been reached for the calculated recovery, accuracy. Precision limits not exceed 1% for both repeatability and reproducibility measurements. F-value and t-value were measured for the suggested LSV method versus the standard HPLC method for the concentration of 8 μM fenitrothion and were found to be 1.482 and 0.123, respectively which didn’t exceed the tabulated values. The ruggedness of the suggested method was examined toward deliberate safranine concentration variations in the concentration range of (0.01 mM–0.03 mM). Insignificant differences for the mean recovery at (98.33–98.93%) and precision at (1.39–2.6%) were observed. Hence, the reliability and validity of the developed LSV method were achieved and it was considered as rigid method.

This piece theorises the limitations of transitioning reflection from individualistic to participatory practice. It addresses the question: what are the challenges of introducing crowd-reflecting into Arab academia? To answer this question, 140 Arabs from an academic organisation were invited to crowd-reflect, online, on their institution, using a five-phase model. The data analysis showed that limited cultures of collaboration, healthy conflict, cross-gender communication, integrity and critical thinking in Arab academia challenged crowd-reflecting. Despite implementing strategies to overcome these challenges, crowd-reflecting resulted in chaos at the institution, forcing management to intervene to stop the project. This chaos ensued because crowd-reflecting, unlike individualistic reflection, entailed numerous individuals and intersubjectivity -- which complicated reflectiveness, turned thoughtful Arab individuals into a mob and jeopardised the well-documented gains of individualistic reflection. Although crowd-reflecting was initiated to improve organisations, it destabilised the institution and turned it into a counter-learning organisation. This implies that, in Arab academia, beyond micro-level small groups, the more participants there are in reflection, the less effective the learning outcomes may be. In Arab academia, meso-level reflection (and, by implication, macro-level reflection such as the mega-reflecting of the Twittersphere) can risk ruining the art of reflectiveness.

This work investigates the validation of the SW-ASV method for the determination of malathion organophosphorus pesticide based on an electrochemically modified (CPE) carbon paste electrode with copper metal. The surface of the modified CPE was constructed by electrodepositing the copper layer at the accumulation step in 1-mM CuSO4.5H2O, PBS at pH 6.6, E accumulation: − 0.8 V, and Taccumulation 240 s. The determining step was performed by adding different concentrations of malathion pesticide and applying the potential toward more positive potential at (− 0.8–+ 1.4 V) to enhance the oxidation of Cu0 metal. It was noticed that the malathion concentration gradient enhances the oxidation peak current of copper at + 0.03 V gradually. SW-ASV method validation was performed at a linearity range confined in (1–10 µM). An analytical curve was constructed and R2 was equal to 0.99995 with good fitted linear relationship. LOD and LOQ were calculated to be 0.0247 and 0.08236 µM, respectively. ANOVA for two sets of measurements using the standard gas chromatographic method and the suggested SW-ASV method was demonstrated via the calculations of F-value and t-value. F and t-values were calculated to be 1.698 and 0.289, respectively, which did not exceed the tabulated F and t-values resulting in the great similarity of results and ensuring the reliability of the suggested test method. This valid SW-ASV method was used to perform the routine analysis of the 95% technical grade and the pesticide formulation 57% emulsion concentrate of the malathion. Valid results were achieved with satisfactory limits of accuracy and precision. [ABSTRACT FROM AUTHOR]

Summary: To evade immunity, many viruses express interferon antagonists that target STAT transcription factors as a major component of pathogenesis. Because of a lack of direct structural data, these interfaces are poorly understood. We report the structural analysis of full-length STAT1 binding to an interferon antagonist of a human pathogenic virus. The interface revealed by transferred cross-saturation NMR is complex, involving multiple regions in both the viral and cellular proteins. Molecular mapping analysis, combined with biophysical characterization and in vitro/in vivo functional assays, indicates that the interface is significant in disease caused by a pathogenic field-strain lyssavirus, with critical roles for contacts between the STAT1 coiled-coil/DNA-binding domains and specific regions within the viral protein. These data elucidate the potentially complex nature of IFN antagonist/STAT interactions, and the spatial relationship of protein interfaces that mediate immune evasion and replication, providing insight into how viruses can regulate these essential functions via single multifunctional proteins. : Hossain et al. explore the binding surface of the multifunctional P-protein of rabies virus for STAT1, a protein that is essential for establishing the antiviral response of infected cells. They identify a complex interface comprising several distinct sites and demonstrate that targeted modifications of these can significantly attenuate pathogenic virus. Keywords: immune evasion, innate immunity, interferon, interferon antagonist, lyssavirus, nuclear magnetic resonance, P protein, rabies, STAT1, virus

Background: In our study, we investigated the effect of adding neostigmine to local anesthetic on the supraclavicular brachial plexus block. Patients and Methods: This prospective, randomized, blinded controlled experiment included 80 patients of either sex with an ASA I or II physical status who were planned for forearm operations under ultrasound-assisted supraclavicular brachial plexus block. Participants were separated randomly into two groups and given a supraclavicular block with 25 mL of 0.5% bupivacaine and 1 mL of 0.9 % saline for the control group and 25 mL of 0.5% bupivacaine and 1 mL of neostigmine (0.5mg) for the neostigmine group. Results: In the neostigmine group, sensory and motor blockade began earlier and lasted longer than in the control group. The neostigmine group took substantially longer to seek their first analgesia. The neostigmine group used fewer analgesics in total. At 1, 2, 4, and 6 hours, the neostigmine group had statistically reduced VAS scores than the control group. Conclusion: Patients undergoing forearm procedures benefit from the usage of neostigmine in addition to bupivacaine in ultrasound-assisted supraclavicular brachial plexus block because it reduces the onset of sensory and motor block and lengthens its duration. These results were clear with a dosage of (0.5 mg). [ABSTRACT FROM AUTHOR]