Behavioral flexibility is associated with changes in structure and function distributed across a frontal cortical network in macaques.

One of the most influential accounts of central orbitofrontal cortex-that it mediates behavioral flexibility-has been challenged by the finding that discrimination reversal in macaques, the classic test of behavioral flexibility, is unaffected when lesions are made by excitotoxin injection rather than aspiration. This suggests that the critical brain circuit mediating behavioral flexibility in reversal tasks lies beyond the central orbitofrontal cortex. To determine its identity, a group of nine macaques were taught discrimination reversal learning tasks, and its impact on gray matter was measured. Magnetic resonance imaging scans were taken before and after learning and compared with scans from two control groups, each comprising 10 animals. One control group learned discrimination tasks that were similar but lacked any reversal component, and the other control group engaged in no learning. Gray matter changes were prominent in posterior orbitofrontal cortex/anterior insula but were also found in three other frontal cortical regions: lateral orbitofrontal cortex (orbital part of area 12 [12o]), cingulate cortex, and lateral prefrontal cortex. In a second analysis, neural activity in posterior orbitofrontal cortex/anterior insula was measured at rest, and its pattern of coupling with the other frontal cortical regions was assessed. Activity coupling increased significantly in the reversal learning group in comparison with controls. In a final set of experiments, we used similar structural imaging procedures and analyses to demonstrate that aspiration lesion of central orbitofrontal cortex, of the type known to affect discrimination learning, affected structure and activity in the same frontal cortical circuit. The results identify a distributed frontal cortical circuit associated with behavioral flexibility.

A cross-sectional study to understand the pervasiveness of psychiatric features among tinnitus and vertigo patients.

OBJECTIVE: To identify the mental health problems among patients having symptoms of tinnitus and vertigo due to vestibulocochlear disturbances. METHODS: The cross-sectional study was conducted from May to September 2019 at the Hearts International Hospital and the Hearing and Balance Clinic, Rawalpindi, in collaboration with the Foundation University, Islamabad, and comprised vestibulocochlear disorder patients of either gender aged >18 years having chief symptoms of vertigo and tinnitus for at least the preceding 3 months. Psychiatric evaluation was conducted using the Tinnitus Handicap Inventory, the Dizziness Handicap Inventory and the Depression, Anxiety, Stress Scale. Audiological evaluations were carried out to gauge the severity of symptoms. Data was analysed using SPSS 20. RESULTS: Of the 202 subjects, 60(30%) were females and 142(70%) were males. Patients experiencing vertigo and tinnitus symptoms had a strong tendency to develop psychiatric problems (p<0.05). Significant differences were noted among male and female patients regarding the representation of psychiatric symptoms (p<0.05). CONCLUSION: Patients experiencing tinnitus and vertigo symptoms tended to have a deviant psychological profile analogous with other chronic diseases.

Prevalence of tuberculosis, HIV/AIDS, and hepatitis; in a prison of Balochistan: a cross-sectional survey.

BACKGROUND: Human Immunodeficiency Virus (HIV), Hepatitis, and Tuberculosis (TB) are three primary communicable infections have the likely potential to cause severe morbidity in prison settings. The prison has the most favorable environment for the transmission of infections. We conducted this survey to determine the prevalence and feasibility of rapid diagnostic tests in an active screening of these infectious diseases in prison. METHODS: This cross-sectional survey conducted in central Jail Gaddani, one of the largest prisons in the Balochistan province of Pakistan. All prisoners, jail staffs, and staff's family members participated. Informed consent obtained from each participant before the screening. Van equipped with digital X-ray linked with Computer-Aided Detection for TB (CAD4TB) software used for testing. Sputum samples tested on Xpert for MTB/RIF assay and blood specimens collected for HIV and hepatitis serology. Diagnosed TB patients enrolled for treatment at Basic Management Unit (BMU), reactive on hepatitis Rapid Diagnostic Tools (RDTs) were referred for further testing and management, while HIV reactive referred to Anti Retro Viral (ARV) center for Anti Retro Viral Treatment (ART). RESULTS: A total of 567 participants offered screening, 63% (356) prisoners, 23% (129) staff's family members, and 14% (82) jail staffs. Among tested 10.3% (58/562) were hepatitis seropositive (Hepatitis-C 41 [7.29%] Hepatitis-B, 16 [2.84%] Hepatitis B&C both, 01 [0.17%]). In reactive participants, 49 were prisoners, 08 were jail staffs, and 01 was the staff's family member. HIV seropositive was 4% (24/566), and all were prisoners. Almost 99% (565/567) screened by digital X-ray, 172 (30%) were with abnormal CAD4TB suggestion (score > 50), out of them sputum of 26% (148) tested on Xpert, and 2% (03) found Mycobacterium tuberculosis Positive (MTB+). A total of five TB patients were detected; out of two were diagnosed clinically. Co-morbidities observed in 15 patients, (01 TB/HIV co-infected, 12 HIV/HCV, 01 HIV/HBV, and 01 HBV/HCV). CONCLUSION: The high frequency of infectious diseases in prison is alarming. For limiting the transmission of infections among prison and community, immediate steps are needed to be taken for improvement of prisons condition by application of recommended screening protocols at the time of the first entry of prisoners in prisons.

Phosphocreatine attenuates endoplasmic reticulum stress-mediated hepatocellular apoptosis ameliorates insulin resistance in diabetes model.

Diabetes mellitus (DM) associated liver damage is a major health burden. Hepatocellular-damage in DM characterized with elevated endoplasmic reticulum stress (ER) and may enhanced insulin-resistance. Phosphocreatine (PCr) a rapidly high-energy-reserve molecule of phosphates naturally occurs in liver, brain and skeletal muscle. This study aimed to investigate the protective effect of PCr on the liver-injury-associated with DM and to report the mechanism involved. Wistar rat's diabetes model was induced using streptozotocin (STZ), and the animals were treated with 20 mg/kg, or 50 mg/kg PCr injection. Blood glucose level, and body wt were recorded. Liver tissues homogenate were analyzed for liver damage markers alanine transaminase (ALT), aspartate transaminase (AST). Liver tissues proteins further evaluated for apoptosis, endoplasmic reticulum stress (ER), and insulin resistance biomarkers using western blotting. Our results revealed that PCr reduced blood glucose level, improved body wt, ameliorates liver function enzymes. Furthermore, PCr upregulates anti-apoptotic Bcl2 proteins expression, and down-regulates significantly pro-apoptotic casp3 and Bax proteins expression in vivo and invitro. Moreover, ER stress CHOP, GRP78 and ATF4 biomarkers level were significantly attenuated in PCr treated animals comparing to STZ diabetes associated liver-damage model with significant improving in insulin-resistance Akt and IRS-1. Our results revealed that treating with PCr in diabetes-associated liver injury models decreased blood glucose level and possess protective effect in-vitro and in-vivo, which could be suggested as potential therapeutic strategy for diabetes associated liver injury patients.

Calretinin interneuron density in the caudate nucleus is lower in autism spectrum disorder.

Autism spectrum disorder is a debilitating condition with possible neurodevelopmental origins but unknown neuroanatomical correlates. Whereas investigators have paid much attention to the cerebral cortex, few studies have detailed the basal ganglia in autism. The caudate nucleus may be involved in the repetitive movements and limbic changes of autism. We used immunohistochemistry for calretinin and neuropeptide Y in 24 age- and gender-matched patients with autism spectrum disorder and control subjects ranging in age from 13 to 69 years. Patients with autism had a 35% lower density of calretinin+ interneurons in the caudate that was driven by loss of small calretinin+ neurons. This was not caused by altered size of the caudate, as its cross-sectional surface areas were similar between diagnostic groups. Controls exhibited an age-dependent increase in the density of medium and large calretinin+ neurons, whereas subjects with autism did not. Diagnostic groups did not differ regarding ionized calcium-binding adapter molecule 1+ immunoreactivity for microglia, suggesting chronic inflammation did not cause the decreased calretinin+ density. There was no statistically significant difference in the density of neuropeptide Y+ neurons between subjects with autism and controls. The decreased calretinin+ density may disrupt the excitation/inhibition balance in the caudate leading to dysfunctional corticostriatal circuits. The description of such changes in autism spectrum disorder may clarify pathomechanisms and thereby help identify targets for drug intervention and novel therapeutic strategies.

Mechanisms for Rapid Adaptive Control of Motion Processing in Macaque Visual Cortex.

A key feature of neural networks is their ability to rapidly adjust their function, including signal gain and temporal dynamics, in response to changes in sensory inputs. These adjustments are thought to be important for optimizing the sensitivity of the system, yet their mechanisms remain poorly understood. We studied adaptive changes in temporal integration in direction-selective cells in macaque primary visual cortex, where specific hypotheses have been proposed to account for rapid adaptation. By independently stimulating direction-specific channels, we found that the control of temporal integration of motion at one direction was independent of motion signals driven at the orthogonal direction. We also found that individual neurons can simultaneously support two different profiles of temporal integration for motion in orthogonal directions. These findings rule out a broad range of adaptive mechanisms as being key to the control of temporal integration, including untuned normalization and nonlinearities of spike generation and somatic adaptation in the recorded direction-selective cells. Such mechanisms are too broadly tuned, or occur too far downstream, to explain the channel-specific and multiplexed temporal integration that we observe in single neurons. Instead, we are compelled to conclude that parallel processing pathways are involved, and we demonstrate one such circuit using a computer model. This solution allows processing in different direction/orientation channels to be separately optimized and is sensible given that, under typical motion conditions (e.g., translation or looming), speed on the retina is a function of the orientation of image components. SIGNIFICANCE STATEMENT: Many neurons in visual cortex are understood in terms of their spatial and temporal receptive fields. It is now known that the spatiotemporal integration underlying visual responses is not fixed but depends on the visual input. For example, neurons that respond selectively to motion direction integrate signals over a shorter time window when visual motion is fast and a longer window when motion is slow. We investigated the mechanisms underlying this useful adaptation by recording from neurons as they responded to stimuli moving in two different directions at different speeds. Computer simulations of our results enabled us to rule out several candidate theories in favor of a model that integrates across multiple parallel channels that operate at different time scales.

Differential feedback modulation of center and surround mechanisms in parvocellular cells in the visual thalamus.

Many cells in both the central visual system and other sensory systems exhibit a center surround organization in their receptive field, where the response to a centrally placed stimulus is modified when a surrounding area is also stimulated. This can follow from laterally directed connections in the local circuit at the level of the cell in question but could also involve more complex interactions. In the lateral geniculate nucleus (LGN), the cells relaying the retinal input display a concentric, center surround organization that in part follows from the similar organization characterizing the retinal cells providing their input. However, local thalamic inhibitory interneurons also play a role, and as we examine here, feedback from the visual cortex too. Here, we show in the primate (macaque) that spatially organized cortical feedback provides a clear and differential influence serving to enhance both responses to stimulation within the center of the receptive field and the ability of the nonclassical surround mechanism to attenuate this. In short, both center and surround mechanisms are influenced by the feedback. This dynamically sharpens the spatial focus of the receptive field and introduces nonlinearities from the cortical mechanism into the LGN.

Long-range clustered connections within extrastriate visual area V5/MT of the rhesus macaque.

Visual area V5/MT in the rhesus macaque has a distinct functional organization, where neurons with specific preferences for direction of motion and binocular disparity are co-organized in columns or clusters. Here, we analyze the pattern of intrinsic connectivity within cortical area V5/MT in both parasagittal sections of the intact brain and tangential sections from flatmounted cortex using small injections of the retrograde tracer cholera toxin subunit b. Labeled cells were predominantly found in cortical layers 2, 3, and 6. Going along the cortical layers, labeled cells were concentrated in regularly spaced clusters. The clusters nearest to the injection site were approximately 2 mm from its center. In flatmounted cortex, along the dorsoventral axis of V5/MT, we identified further clusters of labeled cells up to 10 mm from the injection site. Quantitative analysis of parasagittal sections estimated average cluster spacing at 2.2 mm; in cortical flatmounts, spacing was 2.3 mm measured radially from the injection site. The results suggest a regular pattern of intrinsic connectivity within V5/MT, which is consistent with connectivity between sites with a common preference for both direction of motion and binocular depth. The long-range connections can potentially account for the large suppressive surrounds of V5/MT neurons.

Red Cell Distribution Width and Prediabetes in Adults in Northern Sudan: A Case-Control Study.

Diabetes mellitus (DM) is a major public health issue worldwide. Red cell distribution width (RDW) has been reported to have predictive value in several diseases, including DM. Few data exist on the association between RDW and the prediabetic stage. Thus, the present study aimed to investigate the association between RDW and prediabetes in adults in Sudan. This case-control study was conducted in Northern Sudan in 2022. The cases (n = 107) were prediabetic patients categorized according to the level of glycated hemoglobin (HbA1c), which ranged from 5.7% to 6.4%, while the controls (n = 107) were healthy participants. A questionnaire was used to collect the data. Standard methods were used to measure the HbAIc level and RDW. Logistic regression analysis was performed. The median (interquartile range (IQR)) of the RDW was significantly higher in prediabetic patients than in the controls (14.5% [13.8-15.3%] vs. 14.1% [13.6-14.7%], p = 0.003). Sex, educational level, occupational status, marital status, cigarette smoking, alcohol consumption, family history of DM, and body mass index were not associated with prediabetes. In the multivariate-adjusted model, higher age and higher RDW were associated with prediabetes. A positive correlation was found between RDW and HbA1c levels (r = 0.19, p = 0.006). In conclusion, this study supports the use of RDW as a predictor of DM.

Association between Helicobacter pylori seropositivity and hypertension among adults in Northern Sudan: a community-based case-control study.

OBJECTIVE: The association between Helicobacter pylori and hypertension is unclear. Herein, we aimed to investigate the association between H. pylori and hypertension among adults in Sudan. METHODS: We conducted a community-based case-control study (175 participants in each arm) in the Wad Hamid district in northern Sudan. Cases comprised adults with hypertension and controls were non-hypertensive adults. We assessed participants' data using a questionnaire. We also conducted rapid H. pylori antibody tests and binary and linear regression analyses. RESULTS: Multivariable logistic regression revealed age (adjusted odds ratio [AOR] 1.05, 95% confidence interval [CI] 1.03-1.07), female sex (AOR 5.50, 95% CI 2.36-12.80), and body mass index (AOR 1.12, 95% CI 1.07-1.17) were significantly associated with hypertension. Moreover, compared with controls, a significantly higher number of patients with hypertension were positive for H. pylori (82/175, 46.9% vs. 46/175, 26.3%). H. pylori seropositivity was associated with systolic blood pressure (coefficient 3.811), diastolic blood pressure (coefficient 3.492), mean blood pressure (coefficient 3.599), and hypertension (AOR 3.15, 95% CI 1.82-5.46). CONCLUSION: Our study revealed a significant positive association between H. pylori seropositivity and hypertension. This finding supports literature recommending the eradication of H. pylori to prevent hypertension and its complications.

Phytochemical profiling of antimicrobial and potential antioxidant plant: Nepeta cataria.

Traditional and phytochemical studies have confirmed the richness and diversity of medicinal plants such as Nepeta cataria (N. cataria), but more studies are needed to complete its metabolite profiling. The objective of this research was to enhance the metabolomic picture and bioactivity of N. cataria for better evaluation. Phytochemical analysis was performed by bio-guided protocols and gas chromatography-mass spectrometry (GC/MS). For this, solvents such as methanol, ethanol, water, acetone, and hexane were used to extract a wide number of chemicals. Antibacterial analysis was performed using the 96-well plate test, Kirby Bauer's disk diffusion method, and the resazurin microdilution test. Antioxidant activity was determined by the DPPH assay and radical scavenging capacity was evaluated by the oxygen radical absorbance capacity (ORAC) assay. GC/MS analysis revealed a total of 247 identified and 127 novel metabolites from all extracts of N. cataria. Water and acetone extracts had the highest identified metabolites (n = 79), whereas methanol extract was the highest in unidentified metabolites (n = 48). The most abundant phytochemicals in methanol extract were 1-isopropylcyclohex-1-ene (concentration = 27.376) and bicyclo [2.2.1] heptan-2-one (concentration = 20.437), whereas in ethanol extract, it was 9,12,15-octadecatrienoic acid (concentration = 27.308) and 1-isopropylcyclohex-1-ene (concentration = 25.854). An abundance of 2 methyl indoles, conhydrin, and coumarin was found in water extracts; a good concentration of eucalyptol was found in acetone extract; and 7,9-di-tert-butyl-1-oxaspiro is the most abundant phytochemicals in hexane extracts. The highest concentration of flavonoids and phenols were identified in hexane and methanol extracts, respectively. The highest antioxidant potential (DPPH assay) was observed in acetone extract. The ethanolic extract exhibited a two-fold higher ORAC than the methanol extract. This examination demonstrated the inhibitory effect against a set of microbes and the presence of polar and non-polar constituents of N. cataria. The results of this study provide a safe resource for the development of food, agriculture, pharmaceutical, and other industrial products upon further research validation.

Neuronal responses during and after the presentation of static visual stimuli in macaque primary visual cortex.

Viewing static visual scenes for several seconds or longer can induce a wide variety of striking percepts, including negative afterimages, fading, and motion aftereffects. To characterize the neuronal bases of such phenomena and elucidate functional circuitry in the visual system, we recorded responses of neurons in primary visual cortex (V1) of anesthetized macaques during and after the presentation of prolonged static visual stimuli. We found that 72% of cells generated significant after-responses (ARs) that outlasted classical off-transients after the cessation of stimuli, and AR amplitude grew with stimulus duration. After the longest stimuli tested (32 s), the amplitude and the time course of the AR were on average comparable to, and correlated with, those of the maintained response evoked while stimuli were present. These observations generally held regardless of cell class: simple, complex, direction selective (DS) or non-DS. The average decay time constant of the AR for orientation-tuned cells was 0.65 s. This is strikingly shorter than time constants observed in the lateral geniculate nucleus, which were on the order of tens of seconds. Cells in V1 that lacked orientation tuning displayed an intermediate time course, with a mean time constant of 4.3 s. These results are consistent with a multistage model in which cells at successive stages adapt to their inputs with progressively shorter time constants. Our findings suggest that the perceptual phenomena of fading and afterimages are shaped by both cortical and subcortical dynamics and provide a physiological framework for the interpretation of recent and long-standing psychophysical observations.

Myocardial tuberculosis and beyond: A rare form of extra pulmonary TB in a young boy.

Myocardial tuberculosis is an exceptionally rare form of extra-pulmonary TB. Few cases were reported world-wide. Here a young snake charmer who had skin tuberculosis 5 yrs back admitted into National institute of diseases of Chest and hospital (NIDCH), Dhaka with the complaints of cough, palpitation and breathlessness for 2 months. He had right axillary firm matted lymphadenopathy, left sided large pleural effusion, left ventricular and septal hypertrophy with band and mass inside the ventricle (evident on CT scan of heart and echocardiography). His ESR was 95 mm in1st hr, Mantaux test was 15mm, Pleural fluid was exudative lymphocyte predominant with adenosin deaminase (ADA) 68.6 U/L. Fine needle aspirates from right axillary LNs showed Mycobacterium tuberculosis on GeneXpert for MTB/RIF testing and caseous granuloma on cytopathological study. Whole Body F18 FDG PET-CT revealed numerous low FDG avid size significant lymph nodes in right side of neck, mediastinum and right axilla with cardiomegaly with focal FDG avid within the left ventricular cavity likely to be prominent papillary muscle. MRI of heart or Myocardial biopsy for histology was not done due to their cost and invasiveness and also for that there was sufficient evidence of having tuberculosis in lymph node, pleura nas myocardium. This patient was treated with anti tubercular medications (3HRZE2S/5HRE) with prednisolone for six months. After treatment, myocardial lesions, pleural effusion and lymphadenopathy were found resolved. Thus a case of fatal and serious tuberculosis was explored and managed successfully.

Safety and Feasibility of Same Day Discharge Strategy for Primary Percutaneous Coronary Intervention.

Background: The strategy for early discharge after primary percutaneous coronary intervention (PCI) could have substantial financial benefits, especially in low-middle income countries. However, there is a lack of local evidence on feasibility and safety of the strategy for early discharge. Therefore, the aim of this study was to assess the safety of early discharge after primary PCI in selected low-risk patients in the population of Karachi, Pakistan. Methods: In this study 600 consecutive low-risk patients who were discharged within 48 hours of primary PCI were put under observation for major adverse cardiac events (MACE) after 7 and 30 days of discharge respectively. Patients were further stratified into discharge groups of very early (≤ 24 hours) and early (24 to 48 hours). Results: The sample consisted of 81.8% (491) male patients with mean age of 54.89 ± 11.08 years. Killip class was I in 90% (540) of the patients. The majority of patients (84%) were discharged within 24 hours of the procedure. Loss to follow-up after rate at 7 and 30 days was 4% (24) and 4.3% (26) respectively. Cumulative MACE rate after 7 and 30 days was observed in 3.5% and 4.9%, all-cause mortality in 1.4% and 2.3%, cerebrovascular events in 0.9% and 1.4%, unplanned revascularization in 0.9% and 1.2%, re-infarction in 0.3% and 0.5%, unplanned re-hospitalization in 0.5% and 0.5%, and bleeding events in 0.5% and 0.5% of the patients respectively. Conclusion: It was observed that very early (≤ 24 hours) discharge after primary PCI for low-risk patients is a safe strategy subjected to careful pre-discharge risk assessment with minimal rate of MACE after 7-days as well as 30-days.

Disparities in clinical features and outcomes of peripartum cardiomyopathy in high versus low prevalent regions in Nigeria.

AIMS: The prospective, multicentre Peripartum Cardiomyopathy in Nigeria (PEACE) registry originally demonstrated a high prevalence of peripartum cardiomyopathy (PPCM) among patients originating from Kano, North-West Nigeria. In a post hoc analysis, we sought to determine if this phenomenon was characterized by a differential case profile and outcome among PPCM cases originating elsewhere. METHODS AND RESULTS: Overall, 199 (81.6%) of a total 244 PPCM patients were recruited from three sites in Kano, compared with 45 patients (18.4%) from 11 widely dispersed centres across Nigeria. Presence and extent of ventricular myocardial remodelling during follow-up, relative to baseline status, were assessed by echocardiography. During median 17 months follow-up, Kano patients demonstrated significantly better myocardial reverse remodelling than patients from other sites. Overall, 50.6% of patients from Kano versus 28.6% from other regions were asymptomatic (P = 0.029) at study completion, with an accompanying difference in all-cause mortality (17.6% vs. 22.2% respectively, P = 0.523) not reaching statistical significance. Alternatively, 135/191 (84.9%) of Kano patients had selenium deficiency (<70 µg/L), and 46/135 (34.1%) of them received oral selenium supplementation. Critically, those that received selenium supplementation demonstrated better survival (6.5% vs. 21.2%; P = 0.025), but the supplement did not have significant impact on myocardial remodelling. CONCLUSIONS: This study has shown important non-racial regional disparities in the clinical features and outcomes of PPCM patients in Nigeria, that might partly be explained by selenium supplementation.

Metabolic Syndrome and Related Inflammation, Prevalence, and Predictive Value of C-Reactive Protein in South Asian Youths.

Background: Metabolic syndrome (MetS) is widely prevalent in the South Asian (SA) population. The syndrome leads to a high risk of premature atherosclerosis and diabetes. Obesity, specifically abdominal obesity, is a central pathological mechanism of disease in this population. Ethnic-specific modified measurements of waist circumference (WC) have been proposed for the diagnosis in various populations, including those of SA phenotype. We studied the prevalence of MetS and subclinical inflammation in young physically fit students in a major urban city of Pakistan. Specifically, we addressed the new lower WC measurement and its relationship with MetS and inflammation. C-reactive protein (CRP) was measured as a marker for subclinical inflammation. Methods: A total of 509 respondents (mean age 19.86 years) filled out self-administered questionnaires for data collection. Measurements were made by trained nurses using standardized equipment and fasting blood samples were drawn for chemical analysis. Data were verified, tabulated, and statistically analyzed. Results: MetS was identified in 6% of this cohort and 16% had subclinical information as measured by CRP. Higher CRP levels were noted with higher WC and independently identified subjects with MetS. CRP levels of ≥2.2 mg/dL predicted presence of MetS. Conclusions: MetS is widely prevalent in young, otherwise physically fit, individuals. High proportion of this young cohort had evidence of subclinical inflammation as measured by CRP. Increasing WC showed significant correlation with higher CRP levels, level of 2.2 mg/dL independently identified MetS in this cohort.

Responses to static visual images in macaque lateral geniculate nucleus: implications for adaptation, negative afterimages, and visual fading.

Adaptation to static scenes is a familiar and fundamental aspect of visual perception that causes negative afterimages, fading, and many other visual illusions. To establish a foundation for understanding the neuronal bases of such phenomena and to constrain the contributions of retinal versus cortical processing, we studied the responses of neurons in the dorsal lateral geniculate nucleus during and after the presentation of prolonged static visual stimuli. We found that parvocellular (P) cells (the more numerous and color-sensitive pathway) showed response adaptation with a time constant on the order of tens of seconds and that their response after the removal of a visual stimulus lasting 1 min was similar in amplitude and time course to the response evoked by the photographic negative stimulus. Magnocellular (M) cells (the faster-conducting and achromatic pathway) had after responses that were substantially weaker than responses evoked by patterned visual stimuli. This difference points to the existence of an adaptive mechanism in the P-pathway that is absent or impaired in the M-pathway and is inconsistent with full adaptation of photoreceptors, which feed both pathways. Cells in both pathways often maintained a substantial tonic response throughout 1 min stimuli, suggesting that these major feedforward inputs to cortex adapt too slowly to account for visual fading. Our findings suggest that faster-adapting mechanisms in cortex are likely to be required to account for the dynamics of perception during and after the viewing of prolonged static images.

Gamma-ray shielding characteristics of flexible silicone tungsten composites.

Silicone being a hybrid elastomer is well known for its excellent thermal and mechanical properties, chemical resistance, compatibility with organic and inorganic fillers, nontoxicity, and flexibility. As the reported literature on silicone tungsten composite is rare, thus, a complete possible spectrum of silicone tungsten composites series with tungsten loading of 0-88.1 %wt has been fabricated by RTV method and studied as a flexible gamma shielding material. Flexible silicone/tungsten composite formulations containing different weight percentages of tungsten powder (0, 30.1, 47.8, 59.8, 68.1, and 88.1 wt %) were developed by the room-temperature vulcanization route. Two lead collimators with diameters of 0.6 cm were used to make a narrow beam geometry for gamma rays emitted from a137Cs (gamma-ray energy of 662 keV) point source. Uncollided flux was measured with a NaI(Tl) scintillation detector enclosed in lead shielding to reduce the background radiation level. The measured mass attenuation coefficient for our composites with 88.1 wt % tungsten was 0.1035 cm2/g, which is nearly 3.5% higher than that of commercially available silicone/tungsten composites named T-Flex (nearly 0.095 cm2/g) containing the same tungsten loading. Similarly, superior half value layers (HVL) of our composites with 88.1 % wt loading of tungsten i.e 1.01 cm versus 1.27 cm for the reported T-Flex counterpart with additional advantage of insitu fabrication on complex geometries. It was also found that the effectiveness of gamma-ray shielding increases with increase in density of the composites, which is due to the increase in the weight percent of tungsten powder. Our material will have applications as shielding material for both mobile and stationary radiation sources and it can also be used as fabrication material for gloves, safety shoes, coats, etc. to protect workers in a radiation environment.

Predictive Factors Associated With Fear Faced by Healthcare Workers During COVID-19 Pandemic: A Questionnaire-Based Study.

Background The coronavirus disease 2019 (COVID-19) since the beginning has been a reason of fear among healthcare workers (HCWs) due to the increased mortality, especially in the HCWs themselves. In this survey study, we aimed to explore the predictive factors associated with fear faced by HCWs during the COVID-19 pandemic and to identify the areas which need to be addressed to reduce it. Methods On May 14, 2020, we conducted an observational, cross-sectional survey using a self-administered questionnaire, consisting of the following two parts: (1) focused on factors associated with HCWs' fear of getting an infection and being a source of carrying the infection to whom they care, and (2) focused on factors associated with HCWs' fear of uncertainty and lack of support from concerned health authorities. Results The mean age of the participants was 40.04 ± 12.92 years with 79.3% being males. More than half (51.1%) of the participants were consultants. The most important factors associated with fear included getting infected (84.8%), quarantined (69.6%), not getting medical treatment (62%), losing a life (56.8%), and infecting family members (94.2%). Another major factor associated with HCWs' fear was lack of support from concerned health authorities, 80.2% thought of solatium, and 71.7% believed that the job should be given to eligible family members of the deceased. More than 82.2% were concerned about health expenses and around 97.6% felt an additional health risk allowance should be given. Conclusion Our results indicate that the risk of getting infection to themselves and their families, along with a lack of support from concerned health authorities, was strongly associated with fear among HCWs. We hope through these findings that the concerned health authorities will take notice and do something in this regard by developing appropriate policies and measures to make sure that HCWs and their families are cared for if they get infected.

Assessing the Quality of Orthopaedic Operation Notes in Accordance With the Royal College of Surgeons Guidelines: An Audit Cycle.

Introduction Accurate and detailed operation notes are of great importance in all surgical specialties not only for patient care but also for providing information for research, audit and medico-legal purposes. In this audit cycle, we assessed the quality of operation notes against the standards set by the Royal College of Surgeons of England. Methodology A sample of 59 operation notes was randomly selected from the orthopaedics department at Ribat University Hospital and retrospectively audited by three reviewers according to the Royal College of Surgeons of England Good Surgical Practice guidelines released in 2014. A memory aid was then placed in the operation theatre, emphasising mainly the points with poor compliance in the audit. A re-audit was then performed for another 59 operation notes. Results During the first audit, 59 elective operation notes were reviewed, and there was good compliance with date documentation (86%), diagnosis (85%), operating surgeon (90%), assistants' names (86%), operative procedure (98%), detailed post-operative instructions (98%) and the signature (75%). In the re-audit phase, another 59 operative notes were reviewed; four of them were emergency operations. An improvement was noted in documenting the information that had been poorly documented in the first audit. In the first audit, 20% of the operation notes were written by the operating surgeon, while only 14% were written by the operating surgeon in the re-audit. Conclusion Our implementation of a memory aid in the operation theatre helped to improve the reporting of some of the criteria; however, some components of the operation notes remained poorly filled in.