Early prognosis of respiratory virus shedding in humans

This paper addresses the development of predictive models for distinguishing pre-symptomatic infections from uninfected individuals. Our machine learning experiments are conducted on publicly available challenge studies that collected whole-blood transcriptomics data from individuals infected with HRV, RSV, H1N1, and H3N2. We address the problem of identifying discriminatory biomarkers between controls and eventual shedders in the first 32 h post-infection. Our exploratory analysis shows that the most discriminatory biomarkers exhibit a strong dependence on time over the course of the human response to infection. We visualize the feature sets to provide evidence of the rapid evolution of the gene expression profiles. To quantify this observation, we partition the data in the first 32 h into four equal time windows of 8 h each and identify all discriminatory biomarkers using sparsity-promoting classifiers and Iterated Feature Removal. We then perform a comparative machine learning classification analysis using linear support vector machines, artificial neural networks and Centroid-Encoder. We present a range of experiments on different groupings of the diseases to demonstrate the robustness of the resulting models.

Comparative analysis of Truenat™ MTB Plus and Xpert® Ultra in diagnosing tuberculous meningitis

BACKGROUND: Diagnostic delay and drug resistance not only worsen the outcomes of tuberculous meningitis (TBM), but are also important impediments to TB elimination efforts. Given the need for a near point-of-care test suitable for primary healthcare centres and simultaneous detection of resistance, Truenat™ MTB Plus assay was evaluated on a large cohort of TBM patients.METHODS: Truenat assay was performed on 148 cerebrospinal fluid specimens (76 definite TBM, 32 probable TBM and 40 non-TBM controls) and its performance was compared with Xpert^® Ultra.RESULTS: The overall sensitivity of Truenat and Ultra was respectively 78.7% and 67.6% in diagnosing TBM, and respectively 85.5% and 96% in diagnosing definite TBM. Twenty-three additional cases were detected using Truenat and 11 using Ultra. Truenat missed seven cases of rifampicin (RIF) resistance and indicated false RIF resistance in four cases.CONCLUSION: Performance of Truenat was comparable to that of Ultra in diagnosing TBM and inferior to Xpert Ultra in determining RIF resistance.

Sustainable engineering of sewers and sewage treatment plants for scenarios with urine diversion

Urine diversion (UD) has been studied for decades as a way to enable distributed sanitation and to recycle nutrients onto land to fuel circular economies. No study to date has attempted a quantitative technical and economic analysis of the downstream effects of UD on sewage transport and treatment. This work used the SeweX model to reveal for the first time that through UD, hydrogen sulfide concentration in sewer headspaces can be reduced, and consequently sewer corrosion can be reduced. For a long rising main of 5 km, sewer headspace H₂S can be reduced from 280 ppm to 200 ppm by diverting 75% of the urine. The same scenario enables the reduction of sewer corrosion from 12 to 10 mm/yr. Modeling sewage treatment plants with BioWin showed that sewage treatment responds to UD with a sharp reduction of the anoxic volume and a decrease of energy requirement by up to 50% at 75% UD. An upgrade of bioreactors to increase capacity by 20% can be completely avoided if 7% of the catchment's urine is diverted. Reductions in upgrade expenditure by up to 75% can provide the economic incentive for the uptake of UD.

Postmeal optogenetic inhibition of dorsal hippocampal principal neurons increases future intake in a time-dependent manner

Research involving human participants indicates that memories of recently eaten meals limit how much is eaten during subsequent eating episodes; yet, the brain regions that mediate the inhibitory effects of ingestion-related memory on future intake are largely unknown. We hypothesize that dorsal hippocampal (dHC) neurons, which are critical for episodic memories of personal experiences, mediate the inhibitory effects of ingestion-related memory on future intake. Our research program aimed at testing this hypothesis has been influenced in large part by our mentor James McGaugh and his research on posttraining manipulations. In the present study, we used an activity-guided optogenetic approach to test the prediction that if dHC glutamatergic neurons limit future intake through a process that requires memory consolidation, then inhibition should increase subsequent intake when given soon after the end of a meal but delayed inhibition should have no effect. Viral vectors containing CaMKIIα-eArchT3.0-eYFP and fiber optic probes were placed in the dHC of male Sprague-Dawley rats. Compared to intake on a day when no inhibition was given, postmeal inhibition of dHC glutamatergic neurons given for 10 min after the end of a saccharin meal increased the likelihood that rats would consume a second meal 90 min later and significantly increased the amount of saccharin solution consumed during that next meal when the neurons were no longer inhibited. Importantly, delayed inhibition given 80 min after the end of the saccharin meal did not affect subsequent intake of saccharin. Given that saccharin has minimal postingestive gastric consequences, these effects are not likely due to the timing of interoceptive visceral cues generated by the meal. These data show that dHC glutamatergic neural activity is necessary during the early postprandial period for limiting future intake and suggest that these neurons inhibit future intake by consolidating the memory of the preceding meal.

Natriuretic Peptide Levels and Clinical Outcomes among Patients Hospitalized with COVID-19 Infection

Purpose

There is increasing evidence of adverse cardiovascular morbidity associated with SARS-CoV-2 (COVID-19). Pro-B-type natriuretic peptide (proBNP) is a biomarker of myocardial stress associated with outcomes in various respiratory and cardiac diseases. We hypothesized that proBNP level would be associated with mortality and clinical outcomes in hospitalized COVID-19 patients.

Methods

We performed a retrospective analysis of hospitalized COVID-19 patients (n=1232) using adjusted logistic and linear regression to assess the association of admission proBNP (analyzed by both categorical cutoff >125 pg/mL and continuous log transformed proBNP) with clinical outcomes. Covariates included age, sex, race, body mass index (BMI), hypertension, coronary artery disease (CAD), diabetes, smoking history, and chronic kidney disease stage (Model 1), with Troponin I added in Model 2. We performed survival analysis by a multivariate Cox proportional hazard model, incorporating log transformed proBNP. We additionally treated BMI, a strong potential confounder of both proBNP levels and COVID-19 outcomes, as an ordinal variable ordered across tertiles.

Results

Patients were mean age 62.9±17.6, 53.8% male, and 35.9% Black. Preadmission comorbidities were hypertension (57.1%), diabetes (31.6%), CAD (9.0%) and heart failure (HF, 10.6%). In Model 1 and 2, higher proBNP level was significantly associated with death, new HF, length of stay, ICU duration and need for ventilation among hospitalized COVID-19 patients. This significance persisted after ordinal compression of BMI across tertiles. The adjusted hazard ratio of death for log[proBNP] was 1.56 (95% CI: 1.23-1.97; P<0.0001).

Conclusion

Using a relatively large and racially diverse hospitalized COVID-19 patient cohort, we find that proBNP is associated with adverse clinical outcomes, including mortality and new HF in COVID-19. Further prospective investigation is warranted on the utility of proBNP for clinical prognostication in COVID-19.

A35 ASSOCIATIONS BETWEEN AUTONOMIC DYSFUNCTION, COLONIC DYSMOTILITY AND ABSENT DEFECATION REFLEXES IN PATIENTS WITH CHRONIC REFRACTORY CONSTIPATION

Background

A defecation reflex involves sensory information from the colon sent to the central nervous system which results in propulsive motor patterns in the colon through programmed neural activity from the autonomic nervous system. Neurological causes of constipation are recognized but specific neurological pathways that contribute to pathophysiology of the disease is underexplored. Diagnosis and treatment usually do not involve the autonomic nervous system.

Aims

Our objective was to assess autonomic dysfunction and abnormal defecation reflexes as a possible cause of chronic constipation.

Methods

Defecation reflexes were assessed by high-resolution colonic manometry through balloon distention, meal intake, and rectal bisacodyl. Specific heart rate variability (HRV) parameters were used to assess general orthostatic autonomic reactivity, and autonomic functioning during high resolution colonic manometry, in 14 patients with chronic refractory constipation considered for surgery.

Results

All patients had a unique combination of motility, reflex ability and HRV profiles. Patients overall did not generate HAPWs or had lower HAPW amplitude and lower propulsive activity compared to healthy individuals. Half of the 14 patients were tested to have high sympathetic tone based on Baevsky’s stress index prior to HRCM, and 11 of the patients had sympathetic hyper-reactivity and/or low parasympathetic reactivity to at least one type of colonic stimulation during HRCM. Abnormal autonomic tone or autonomic reactivity to colonic stimulation was present in all four patients with absence of the vagosacral defecation reflex. Five of the seven patients with absence of the sacral defecation reflex showed high sympathetic tone or high sympathetic reactivity to stimulation. Only two patients had abnormality in coloanal coordination and this was associated with low parasympathetic reactivity to stimulation in both patients.

Conclusions

The assumption that colonic resection was needed to remove an inert colon was wrong in most patients, but most patients had some form of reflex abnormality. Sympathetic dominance far outweighed parasympathetic dysfunction. Incorporation of assessments of defecation reflexes and autonomic nervous system activity into diagnosis of chronic refractory constipation provides a comprehensive pathophysiological understanding of specific defective neurological pathways contributing to dysmotility. This forms the basis for our individualized treatment efforts through sacral neuromodulation.

Funding Agencies

CIHR

Low-voltage low-noise gate driven quasi-floating bulk self-cascode current mirror operational transconductance amplifier

A gate driven quasi-floating bulk self-cascode current mirror operational transconductance amplifier operable at ±0.9 V supply voltage with DC gain (70 dB), gain bandwidth (250 kHz), noise (2.8 µV/√Hz at 1 Hz), and power consumption (2.96 µW) simulated in 0.18 µm technology has been introduced. Results obtained are superior in comparison to gate driven self-cascode current mirror and regular current mirror OTAs, which can be utilized to improve the performance of analog-mixed signal circuits and systems.

Online Learning in the Face of COVID-19 Pandemic: Assessment of Students' Satisfaction at Chitwan Medical College of Nepal

Background Online learning can play a vital role in the process of teaching and learning during Corona Virus Disease 2019 (COVID-19) pandemic. However, learners' satisfaction is extremely important in effective implementation of the online learning, especially at institutions where it is newly adopted. Objective To assess satisfaction towards online learning and its predictors among students at Chitwan Medical College, Bharatpur. Method A web-based cross-sectional survey was undertaken among 434 undergraduate and postgraduate students from various academic programs who had participated in the online classes started during this COVID-19 pandemic. A structured questionnaire consisting of 31 items (5-point Likert scale) covering four major student satisfaction domains (learners' dimensions, technological characteristics, instructors' characteristics and course management and coordination) was distributed to the students using Google Form. Result More than half (53.5%) of the students were satisfied with the online learning, while 29.7% gave neutral views. Bivariate analyses found that all four domains scores were positively correlated with each other as well as with the students' overall satisfaction towards learning. In multivariate analysis, female gender [aOR: 2.72, p = 0.013], WiFi as internet modality for learning [aOR: 3.36, p = 0.001) and learners' dimension score [aOR: 1.27, p<0.001] were the significant predictors of students' satisfaction. Conclusion Although recently adopted, the satisfaction of the students towards online classes appears good, and prioritizing the identified predictors and working on the weak links could assist in enhancing students' satisfaction and better outcomes.

Impact of lockdown measures in abating the COVID-19 pandemic: Lessons from India’s phased approach

Background

World Health Organization (WHO) declared that the outbreak of novel coronavirus (2019-nCoV) constituted a Public Health Emergency of International Concern (PHEIC) on 30 January 2020 and characterized the novel coronavirus disease (COVID-19) as a pandemic on 11 March 2020. India enacted such measures early on for effective mitigation and suppression to reduce community transmission, including an onerous national lockdown. The impact of the health system governance is quite apparent among all stakeholders including the public in such emergency contexts.

Methods

We compiled the daily data on the number of COVID-19 cases, recoveries and deaths from January 30th until June 16th, 2020. Different stages were categorized from post PHEIC declaration (pre-lockdown) phase to lockdown phases and unlocking phase as implemented. The several measures adopted by the national government were structured in four broad categories as Governance and socioeconomic, travel restrictions, lockdown and public health measures. These measures were compared during each phase.

Results

It was revealed that while the cases are rising the phased restrictions has helped in delaying the peak and remarkably interrupted the rate of transmission. The national average doubling rate was 3 days at the beginning which improved to 22 days. The basic reproduction number remained close to 1 during the last week of lockdown. However, the initial interruption of needed aid and technical support had negative social and economic impacts on the affected population.

Conclusions

As the situation abates following the measures adopted by the government, an articulate strategy of unlocking through increased testing and prompt isolation needs to be developed for more effective reduction and protecting the livelihoods allowing to further relax the lockdown measures.

Key messages

There is need for the local government to consider a strategic easing of the lockdown for protecting the rights of the most affected population.

As the transmission rates are low, the easing of lockdown can be benefited from improved testing and prompt isolation.

Embelin modulates metabolic endotoxemia and associated obesity in high fat diet fed C57BL/6 mice

The present study was designed to investigate the effect of embelin in metabolic endotoxemia (ME) mediated inflammation and associated obesity in high fat diet (HFD)-fed C57BL/6 mice. The molecular docking of embelin confirms its binding with the toll-like receptor-4 (TLR-4). In vivo study, mice were treated with HFD for 8 weeks to induce ME mediated inflammation and associated obesity. Further, mice were treated with embelin (50 and 100 mg/kg/day, p.o.) and orlistat (10 mg/kg/day, p.o.) from 5th to 8th week along with HFD to improve associated changes. After 8 weeks, mice were euthanized and assessed for body weight, body mass index (BMI), fat pad weights (mesenteric, retroperitoneal, and epididymal), intestinal permeability, TLR-4, tumor necrosis factor-α, interleukin-6, lipopolysaccharide, and serum lipid levels followed by histopathological analysis of liver and adipose tissues. Embelin significantly decreased the body weight, BMI, serum lipid levels, ME, and inflammation manifested by above parameters. Further, results of histopathological study showed that embelin restored the vacuolization, inflammation, one side shifting of nucleus in liver tissue, and decreased adipocyte cells size in adipose tissue in HFD-fed mice. Thus, our findings provide the strong evidence first time that embelin could modulate ME, mediate inflammation, and consequently reduce body weight gain, BMI, and serum lipid levels in HFD-fed mice.

Design and simulation of pseudo-resistor with extremely high linearity for an improved neural signal recording

Design of a pseudo-resistor (PR) structure based on a bulk driven quasi floating technique is presented, which not only provides a high value of resistance (≈1 TΩ) over a wider voltage swing of -1 V to 1 V, but also displays extremely high linearity. The same is useful for accurate amplification and recording of neural signals for better diagnosis of many chronic diseases. PR design reported in this paper has been simulated in 0.18 µm technology with BSIM3V3 MOS device models in the 6M1P standard process. The proposed PR has been simulated for its accuracy through its use in the design of the neural amplifier with a display of better performance than earlier reported work.