Nevin Manimala

Sci Rep. 2021 Dec 10;11(1):23824. doi: 10.1038/s41598-021-02623-2.

ABSTRACT

Loess presents very unique collapsible behaviour due to its special under-compactness, weak cementation and porousness. Many environmental issues and geological hazards including subgrade subsidences, slope collapses or failures, building cracking and so on are directly caused by the collapsible deformation of loess. Such collapsible behaviour may also severe accidents due to sinkholes, underground caves or loess gullies. Moreover, with the increasing demand of construction and development in the loess areas, an in-depth research towards effective evaluation of loess collapsibility is urged. Currently no studies have made attempts to explore a rather complete and representative area of Loess Plateau. This paper thus provides a novel approach on spatial modelling over Jin-Shan Loess Plateau as an extension to experimental studies. The in-lab experiment results have shown that shown that the porosity ratio and collapsibility follow a Gaussian distribution and a Gamma distribution respectively for both sampling areas: Yan’an and Lv Liang. This establishes the prior intuition towards spatial modelling which provides insights of potential influential factors on loess collapsibility and further sets a potential direction of the loess studies by considering an extra dimension of spatial correlation. Such modelling allows robust predictions taken into account of longitudinal information as well as structural parameters and basic physical properties. Water contents, dry densities, pressure levels and elevations of samples are determined to be statistically significant factors which affect the loess collapsibility. All regions in Lv Liang area are at risk of high collapsibility with average around 0.03, out of which roughly a third of them are predicted to be at high risk. Clear spatial patterns of higher expected collapsibility in the southwest comparing to the northeast are shown adjusting for influential covariates. On reference guidelines for potential policy makings, county-level regions with the highest expected loess collapsibility are also identified.

PMID:34893645 | DOI:10.1038/s41598-021-02623-2

Nat Commun. 2021 Dec 10;12(1):7223. doi: 10.1038/s41467-021-27568-y.

ABSTRACT

The pedestrian-induced instability of the London Millennium Bridge is a widely used example of Kuramoto synchronisation. Yet, reviewing observational, experimental, and modelling evidence, we argue that increased coherence of pedestrians’ foot placement is a consequence of, not a cause of the instability. Instead, uncorrelated pedestrians produce positive feedback, through negative damping on average, that can initiate significant lateral bridge vibration over a wide range of natural frequencies. We present a simple general formula that quantifies this effect, and illustrate it through simulation of three mathematical models, including one with strong propensity for synchronisation. Despite subtle effects of gait strategies in determining precise instability thresholds, our results show that average negative damping is always the trigger. More broadly, we describe an alternative to Kuramoto theory for emergence of coherent oscillations in nature; collective contributions from incoherent agents need not cancel, but can provide positive feedback on average, leading to global limit-cycle motion.

PMID:34893627 | DOI:10.1038/s41467-021-27568-y

Sci Rep. 2021 Dec 10;11(1):23773. doi: 10.1038/s41598-021-02666-5.

ABSTRACT

Previous molecular characterization studies conducted in Canadian wheat cultivars shed some light on the impact of plant breeding on genetic diversity, but the number of varieties and markers used was small. Here, we used 28,798 markers of the wheat 90K single nucleotide polymorphisms to (a) assess the extent of genetic diversity, relationship, population structure, and divergence among 174 historical and modern Canadian spring wheat varieties registered from 1905 to 2018 and 22 unregistered lines (hereinafter referred to as cultivars), and (b) identify genomic regions that had undergone selection. About 91% of the pairs of cultivars differed by 20-40% of the scored alleles, but only 7% of the pairs had kinship coefficients of < 0.250, suggesting the presence of a high proportion of redundancy in allelic composition. Although the 196 cultivars represented eight wheat classes, our results from phylogenetic, principal component, and the model-based population structure analyses revealed three groups, with no clear structure among most wheat classes, breeding programs, and breeding periods. F_ST statistics computed among different categorical variables showed little genetic differentiation (< 0.05) among breeding periods and breeding programs, but a diverse level of genetic differentiation among wheat classes and predicted groups. Diversity indices were the highest and lowest among cultivars registered from 1970 to 1980 and from 2011 to 2018, respectively. Using two outlier detection methods, we identified from 524 to 2314 SNPs and 41 selective sweeps of which some are close to genes with known phenotype, including plant height, photoperiodism, vernalization, gluten strength, and disease resistance.

PMID:34893626 | DOI:10.1038/s41598-021-02666-5

Nat Commun. 2021 Dec 10;12(1):7217. doi: 10.1038/s41467-021-27410-5.

ABSTRACT

The UK prioritised delivery of the first dose of BNT162b2 (Pfizer/BioNTech) and AZD1222 (AstraZeneca) vaccines by extending the interval between doses up to 12 weeks. In 750 participants aged 50-89 years, we here compare serological responses after BNT162b2 and AZD1222 vaccination with varying dose intervals, and evaluate these against real-world national vaccine effectiveness (VE) estimates against COVID-19 in England. We show that antibody levels 14-35 days after dose two are higher in BNT162b2 recipients with an extended vaccine interval (65-84 days) compared with those vaccinated with a standard (19-29 days) interval. Following the extended schedule, antibody levels were 6-fold higher at 14-35 days post dose 2 for BNT162b2 than AZD1222. For both vaccines, VE was higher across all age-groups from 14 days after dose two compared to one dose, but the magnitude varied with dose interval. Higher dose two VE was observed with >6 week interval between BNT162b2 doses compared to the standard schedule. Our findings suggest higher effectiveness against infection using an extended vaccine schedule. Given global vaccine constraints these results are relevant to policymakers.

PMID:34893611 | DOI:10.1038/s41467-021-27410-5

Ann Afr Med. 2021 Oct-Dec;20(4):297-301. doi: 10.4103/aam.aam_65_20.

ABSTRACT

BACKGROUND: Hepatitis C virus (HCV) co-infection with human immunodeficiency virus (HIV) exists as both viruses have the common routes of transmission. HIV infection has adverse effect on the natural history of HCV infection; however, the effect of HCV infection on the natural history of HIV infection is unclear.

MATERIALS AND METHODS: This study was cross-sectional comprising of treatment-naïve adult HIV-infected patients attending clinics at Usmanu Danfodiyo University Teaching Hospital, Sokoto and Specialist Hospital Sokoto. The study participants were screened for HCV anti]body and assayed for transaminases and CD4⁺ T-lymphocytes count levels. The symptoms of acquired immunodeficiency syndrome (AIDS)-defining illnesses were asked among the study participants. The questionnaire was used for the collection of data, and SPSS software version 20 was used for the analysis of data. Student’s t-tests, Pearson’s, Chi-square, and Fisher’s exact tests were used for the statistical analysis, and P < 0.05 was considered statistically significant.

RESULTS: The prevalence of HIV/HCV co-infection was 20.6%. Self-intravenous drugs usage was not statistically significant (P = 0.210). HIV mono-infected patients had significantly lower alanine aminotransferase levels compared to HIV/HCV co-infected study participants (P = 0.048). AIDS status at the baseline was comparable between HIV mono-infected and HIV/HCV co-infected study participants. (P = 0.227; 0.200; 0.130).

CONCLUSION: Moderately high prevalence of HIV/HCV co-infection was observed in the current study. HCV co-infection had no effect on AIDS status at baseline. There is a need for routine screening of HCV infection in HIV-infected individuals.

PMID:34893569 | DOI:10.4103/aam.aam_65_20

Ann Afr Med. 2021 Oct-Dec;20(4):276-281. doi: 10.4103/aam.aam_61_20.

ABSTRACT

AIM: The aim of the study was to evaluate the 1-year outcome of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy in an eye unit in sub-Saharan Africa.

METHODOLOGY: This retrospective study included 182 eyes of 172 patients managed in the vitreoretinal unit between 2016 and 2019 who were treated with intravitreal anti-VEGF bevacizumab (1.25 mg/0.05 ml) with at least 1 year of follow-up. The outcome measures were change in best-corrected visual acuity (BCVA) over 1 year of follow-up, the number of injections taken, and complications.

RESULTS: The mean age was 61.1 ± 16.3 years (male-to-female ratio of 1:1.1) and about 62.1% above >60 years. A total of 330 injections were given during the period audited. The mean number of injections was 1.8 ± 0.93. Ninety-four (51.7%) eyes had only one injection, while 33 (18.1%), 50 (27.5%), and 5 (2.7%) had 2, 3, and 4 injections, respectively. About 78.5% had moderate-to-severe visual impairment at baseline and 44.5%, 16.4%, 12.6%, and 7.1% at 1, 3, 6, and 12 months post injections, respectively. The mean BCVA improved for all eyes from 1.67 ± 0.91 logarithm of minimum angle of resolution (logMAR) at baseline to 1.50 ± 1.27 logMAR at 1 year. The logMAR letters gained was 23 at 1 month and 8.25 at 1 year; the eyes that had three injections gained 10 letters, while those that had one injection gained three letters. Eyes with age-related macular degeneration and idiopathic polypoidal choroidopathy gained 7.5 and 9 letters, respectively, at 1 year after at least three injections. There was a statistically significant association between an increasing number of injections and improved visual outcome (P = 0.043). One patient each developed endophthalmitis (0.6%) and inferior retinal detachment (0.6%) post injection.

CONCLUSION: Visual acuity gain was recorded in patients who had intravitreal anti-VEGF injections in 1 year. It is recommended that patients should have more than one injection.

PMID:34893565 | DOI:10.4103/aam.aam_61_20

Ann Afr Med. 2021 Oct-Dec;20(4):270-275. doi: 10.4103/aam.aam_59_20.

ABSTRACT

BACKGROUND: Alleviation of labour pain is known to improve maternal and fetal outcome. Combined Spinal-Epidural (CSE) analgesia is an excellent method.

AIM AND OBJECTIVES: In view of reports of its concerns on labour, this study was conducted to evaluate the progress of labour, obstetric outcome in cases with and without CSE analgesia, the maternal pain relief and fetomaternal adverse effects.

MATERIALS AND METHODS: In this comparative study, 60 parturients were allocated into case and control groups of 30 each. CSE analgesia was administered utilizing 0.5 ml of 0.125% Levobupivacaine / 0.2% Ropivacaine with 2 mcg/ml fentanyl. Progress of labour was recorded in partogram including duration of labour, mode of delivery, pain relief – Visual Analogue Scale (VAS) score, development of motor block, maternal satisfaction and Apgar score. Data was analyzed by Descriptive and Inferential statistics.

RESULTS: Mean duration of first and second stage of labour among cases was 530±44.1 minutes, 61.5±12.7 minutes respectively and that of control was 526.6±64.9 minutes, 60±10.8 minutes respectively with no prolongation of labour P > 0.05. CSE analgesia did not alter the mode of delivery P=0.145 with rapid onset of pain relief. Apgar score was normal in both groups. Total 29 (97%) parturients experienced effective labour analgesia following CSE analgesia with VAS score 0. Maternal adverse effects included pruritus, transient initial motor blockade and post spinal headache.

CONCLUSION: CSE analgesia did not affect the duration of labour, mode of delivery with minimal fetomaternal adverse effects and provides rapid onset of pain relief . CSE analgesia can be considered for safe and effective labour analgesia.

PMID:34893564 | DOI:10.4103/aam.aam_59_20

Neurology. 2021 Dec 10:10.1212/WNL.0000000000013119. doi: 10.1212/WNL.0000000000013119. Online ahead of print.

ABSTRACT

OBJECTIVE: To 1) compare adherence to antiseizure medications (ASMs) versus non-ASMs among individuals with epilepsy, 2) assess the degree to which variation in adherence is due to differences between individuals versus between medication classes among individuals with epilepsy, and 3) compare adherence in individuals with versus without epilepsy.

METHODS: This was a retrospective cohort study using Medicare. We included beneficiaries with epilepsy (≥1 ASM, plus International Classification of Diseases, Ninth Revision, Clinical Modification diagnostic codes), and a 20% random sample without epilepsy. Adherence for each medication class was measured by the proportion of days covered (PDC) in 2013-2015. We used Spearman correlation coefficients, Cohen’s kappa statistics, and multilevel logistic regressions.

RESULTS: There were 83,819 beneficiaries with epilepsy. Spearman correlation coefficients between ASM PDCs and each of the 5 non-ASM PDCs ranged 0.44-0.50, Cohen’s kappa ranged 0.33-0.38, and within-person differences between each ASM’s PDC minus each non-ASM’s PDC were all statistically significant (p<0.01) though median differences were all very close to 0. Fifty-four percent of variation in adherence across medications was due to differences between individuals. Adjusted predicted probabilities of adherence were: ASMs 74% (95% confidence interval [CI] 73%-74%), proton pump inhibitors 74% (95% CI 74%-74%), antihypertensives 77% (95% CI 77%-78%), selective serotonin reuptake inhibitors 77% (95% CI 77%-78%), statins 78% (95% CI 78%-79%), and levothyroxine 82% (95% CI 81%-82%). Adjusted predicted probabilities of adherence to non-ASMs were 80% (95% CI 80%-81%) for beneficiaries with epilepsy versus 77% (77%-77%) for beneficiaries without epilepsy.

CONCLUSION: Among individuals with epilepsy, ASM and non-ASM adherence were moderately correlated, half of variation in adherence was due to between-person rather than between-medication differences, adjusted adherence was slightly lower for ASMs than several non-ASMs, and epilepsy was associated with a quite small increase in adherence to non-ASMs. Nonadherence to ASMs may provide an important cue to the clinician to inquire about adherence to other potentially life-prolonging medications as well. Although efforts should focus on improving ASM adherence, patient-level rather than purely medication-specific behaviors are also critical to consider when developing interventions to optimize adherence.

PMID:34893556 | DOI:10.1212/WNL.0000000000013119

J Neurosci. 2021 Dec 10:JN-RM-1487-21. doi: 10.1523/JNEUROSCI.1487-21.2021. Online ahead of print.

ABSTRACT

The striatum’s complex microcircuit is made by connections within and between its D1- and D2-receptor expressing projection neurons and at least five species of interneuron. Precise knowledge of this circuit is likely essential to understanding striatum’s functional roles and its dysfunction in a wide range of movement and cognitive disorders. We introduce here a Bayesian approach to mapping neuron connectivity using intracellular recording data, which lets us simultaneously evaluate the probability of connection between neuron types, the strength of evidence for it, and its dependence on distance. Using it to synthesise a complete map of the mouse striatum, we find strong evidence for two asymmetries: a selective asymmetry of projection neuron connections, with D2 neurons connecting twice as densely to other projection neurons than do D1 neurons, but neither subtype preferentially connecting to another; and a length-scale asymmetry, with interneuron connection probabilities remaining non-negligible at more than twice the distance of projection neuron connections. We further show our Bayesian approach can evaluate evidence for wiring changes, using data from the developing striatum and a mouse model of Huntington’s disease. By quantifying the uncertainty in our knowledge of the microcircuit, our approach reveals a wide range of potential striatal wiring diagrams consistent with current data.SIGNIFICANCE STATEMENTTo properly understand a neuronal circuit’s function, it is important to have an accurate picture of the rate of connection between individual neurons and how this rate changes with the distance separating pairs of neurons. We present a Bayesian method for extracting this information from experimental data and apply it to the mouse striatum, a subcortical structure involved in learning and decision-making, which is made up of a variety of different projection neurons and interneurons. Our resulting statistical map reveals not just the most robust estimates of the probability of connection between neuron types, but also the strength of evidence for them, and their dependence on distance.

PMID:34893550 | DOI:10.1523/JNEUROSCI.1487-21.2021

Proc Natl Acad Sci U S A. 2021 Dec 14;118(50):e2118893118. doi: 10.1073/pnas.2118893118.

NO ABSTRACT

PMID:34893544 | DOI:10.1073/pnas.2118893118