Confinement-induced clustering of H2 and CO2 gas molecules in hydrated nanopores.

Gas molecule clustering within nanopores holds significance in the fields of nanofluidics, biology, gas adsorption/desorption, and geological gas storage. However, the intricate roles of nanoconfinement and surface chemistry that govern the formation of gas clusters remain inadequately explored. In this study, through free energy calculation in molecular simulations, we systematically compared the tendencies of H2 and CO2 molecules to aggregate within hydrated hydrophobic pyrophyllite and hydrophilic gibbsite nanopores. The results indicate that nanoconfinement enhances gas dimer formation in the nanopores, irrespective of surface chemistry. However, surface hydrophilicity prohibits the formation of gas clusters larger than dimers, while large gas clusters form easily in hydrophobic nanopores. Despite H2 and CO2 both being non-polar, the larger quadrupole moment of CO2 leads to a stronger preference for dimer/cluster formation compared to H2. Our results also indicate that gases prefer to enter the nanopores as individual molecules, but exit the nanopores as dimers/clusters. This investigation provides a mechanistic understanding of gas cluster formation within nanopores, which is relevant to various applications, including geological gas storage.

Cable Ties: Poor Man's Top Closure System.

Scalp electrical burns unsuitable for primary closure after debridement have traditionally been treated by modalities that cause significant morbidity and are aesthetically inferior to tension-free primary wound closure. Due to advances in research on the biomechanical properties of skin, various devices for skin stretching and safe wound closure have been reported in the literature that are expensive and inaccessible to poor people in the developing countries. We present our experience using cable ties as an effective, easy to use, readily available, and inexpensive top closure system.

Exposure to Toxocara Canis is not Associated with New-Onset Epilepsy.

Purpose: The association between exposure to Toxocara canis and epilepsy is at the best contentious. Most of previous studies were retrospective, community-based, and contradictory to one another. As the impact of a positive association on the magnitude of epilepsy will be huge especially in developing countries where toxocariasis is common owing to poor hygienic practices, this study was carried out to determine whether exposure to T. canis predisposes to development of epilepsy. Patients and Methods: This case-controlled observational study was carried out a tertiary healthcare center in North India on 120 patients with newly diagnosed epilepsy who presented within 3 months of diagnosis. A total of 120 age- and sex-matched individuals from the same community were chosen as controls. Epilepsy was defined according to ILAE 1993 definition. Serological testing for T. canis was carried out using commercially available ELISA kits. All the positive samples were subjected to Western blot testing for confirmation. Results: The prevalence of antibodies to T. canis was similar in cases (16/120; 13.3%) and controls (16/120; 13.3%). Among the various risk factors, history of pica was significantly associated with T. canis seropositivity, while lack of hand washing was significantly associated with higher risk of epilepsy. Conclusion: Our study could not find any association between exposure to T. canis and epilepsy.

Interaction of Short-Chain PFAS with Polycationic Gels: How Much Fluorination is Necessary for Efficient Adsorption?

The short-chain per- and polyfluorinated alkyl substances (PFAS), introduced to replace the legacy PFAS compounds, turned out to be as toxic and harmful as their longer-chain predecessors and even harder to sequester from contaminated water sources. In this work, molecular dynamics (MD) simulations are employed to investigate the adsorption mechanism of GenX, a representative compound for short-chain PFAS, on a polycationic hydrogel with various extents of fluorination in its backbone and cross-linkers. Simulations indicate that the presence of fluorinated segments next to cationic groups in the polymer gel structure provides the most efficient environment for GenX adsorption. The combination of electrostatic and hydrophobic interactions offered by the cationic-fluorophilic segments amplifies the binding of GenX molecules compared to polymer segments with nonfluorinated cationic or noncationic fluorinated segments. Moreover, such a gel demonstrates high selectivity toward GenX against its hydrogenated analogue.

Green Polymer Electrolytes Based on Polycaprolactones for Solid-State High-Voltage Lithium Metal Batteries.

Solid polymer electrolytes (SPEs) have attracted considerable attention for high energy solid-state lithium metal batteries (LMBs). In this work, potentially ecofriendly, solid-state poly(ε-caprolactone) (PCL)-based star polymer electrolytes with cross-linked structures (xBt-PCL) are introduced that robustly cycle against LiNi0.6 Mn0.2 Co0.2 O2 (NMC622) composite cathodes, affording long-term stability even at higher current densities. Their superior features allow for sufficient suppression of dendritic lithium deposits, as monitored by 7 Li solid-state NMR. Advantageous electrolyte|electrode interfacial properties derived from cathode impregnation with 1.5 wt% PCL enable decent cell performance until up to 500 cycles at rates of 1C (60 °C), illustrating the high potential of PCL-based SPEs for application in high-voltage LMBs.

Impact of the COVID-19 Pandemic on the Frequency, Clinical Spectrum and Outcomes of Pediatric Guillain-Barré Syndrome in India: A Multicentric Ambispective Cohort Study.

Objective: To study impact of COVID-19 pandemic on frequency, clinical/electrophysiological profile and treatment outcomes in pediatric Guillain-Barré syndrome (GBS). Background: GBS is the most frequent cause of pediatric acute flaccid paralysis. The effect of the COVID-19 pandemic on pediatric GBS is unclear in the literature. Methods: We conducted an ambispective, multicentric, cohort study involving 12 of 27 centres in GBS Consortium, during two periods: pre-COVID-19 (March-August 2019) and during COVID-19 (March-August 2020). Children ≤12 years who satisfied National Institute of Neurological Diseases and Stroke criteria for GBS/variants were enrolled. Details pertaining to clinical/laboratory parameters, treatment and outcomes (modified Rankin Scale (mRS) at discharge, GBS Disability score at discharge and 3 months) were analysed. Results: We enrolled 33 children in 2019 and 10 in 2020. Children in 2020 were older (median 10.4 [interquartile range 6.75-11.25] years versus 5 (2.5-8.4) years; P = 0.022) and had more sensory symptoms (50% versus 18.2%; P = 0.043). The 2020 group had relatively favourable mRS at discharge (median 1 (1-3.5) versus 3 (2-4); P = 0.042) and GBS disability score at 3 months (median 0 (0-0.75) versus 2 (0-3); P = 0.009) compared to 2019. Multivariate analysis revealed bowel involvement (P = 0.000) and ventilatory support (P = 0.001) as independent predictors of disability. No child in 2020 had preceding/concurrent SARS-CoV2 infection. Conclusions: The COVID-19 pandemic led to a marked decline in pediatric GBS presenting to hospitals. Antecedent illnesses, clinical and electrophysiological profile of GBS remained largely unchanged from the pre-pandemic era.

GenX in water: Interactions and self-assembly.

2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propanoate, a.k.a. "GenX", is a surfactant introduced as a safer alternative to replace perfluorooctanoate (PFOA) in the manufacturing of fluorinated polymers, however, GenX is shown to cause adverse health effects similar to, or even worse than, those of the legacy PFOA. With an overarching goal to understand the behavior of GenX molecules in aqueous media, we report here on GenX micelle formation and structure in aqueous solutions, on the basis of results obtained from a combination of experimental techniques such as surface tension, fluorescence, viscosity, and small-angle neutron scattering (SANS), and molecular dynamics (MD) simulations. To our best knowledge, this is the first report on GenX micelles. The critical micelle concentration (CMC) of GenX ammonium salt in water is 175 mM. GenX forms small micelles with association number 6-8 and 10 Å radius. GenX molecules prefer to align along the micelle surface, and the ether oxygen of GenX has very little interaction with and exposure to water. Information on the surfactant and interfacial properties of GenX is crucial, since such properties are manifestations of interactions between GenX molecules and between GenX and water molecules and, in turn, the amphiphilic character of GenX dictates its fate and transport in the aqueous environment, its interactions with various biomolecules, and its binding to adsorbent materials.

Impact of COVID-19 on Guillain-Barre Syndrome in India: A Multicenter Ambispective Cohort Study.

Introduction/Aims: Studies conducted during the coronavirus disease 2019 (COVID-19) pandemic have reported varied data regarding the incidence of Guillain-Barre syndrome (GBS). The present study investigated demographic and clinical features, management, and outcomes of patients with GBS during a specified period of the COVID-19 pandemic, and compared these features to those of GBS in the previous year. Methods: A multicenter, ambispective cohort study including 26 centers across India was conducted. Data from a pre-COVID-19 period (March 1 to August 31, 2019) were collected retrospectively and collected ambispectively for a specified COVID-19 period (March 1 to August 31, 2020). The study was registered with the Clinical Trial Registry India (CTRI/2020/11/029143). Results: Data from 555 patients were included for analysis: pre-COVID-19 (n = 334) and COVID-19 (n = 221). Males were more commonly affected during both periods (male:female, 2:1). Gastroenteritis was the most frequent antecedent event in 2019 (17.4%), whereas fever was the most common event in 2020 (10.7%). Paraparesis (21.3% versus [vs.] 9.3%, P = 0.001) and sensory involvement (51.1% vs. 41.3%; P = 0.023) were more common during COVID-19 in 2020, whereas back pain (26.3% vs. 18.4%; P = 0.032) and bowel symptoms (20.7% vs. 13.7%; P = 0.024) were more frequent in the pre-COVID period. There was no difference in clinical outcomes between the two groups in terms of GBS disability score at discharge and 3 months after discharge. Independent predictors of disability in the pre-COVID period included areflexia/hyporeflexia, the requirementfor intubation, and time to bulbar weakness; in the COVID-19 period, independent predictors included time from onset to admission, intubation, and intubation requirement. The mortality rate was 2.3% during the entire study period (13/555 cases). Discussion: Results of this study revealed an overall reduction in the frequency of GBS during the pandemic. The lockdown likely reduced the risk for antecedent infections due to social distancing and improved hygiene, which may have resulted in the reduction of the frequency of GBS.

Experimental investigation and modelling the effect of humic acid on coagulation efficiency for sludge blanket clarifier.

The physicochemical process of coagulation has largely been used for turbidity removal for water treatment. However, lately, the intrusion of NOM (Natural organic matter) in the surface water sources due to climate change has impeded the dosing approaches and has presented a requirement to evaluate the effect of NOM on turbidity removal efficiency and the performance of coagulation reactors in general. In this work, a previously developed performance model for hydraulic flocculators was modified and tested for a sludge blanket clarifier (SBC) which is a type of hydraulic flocculator. The experimental runs were conducted by preparing synthetic sample waters by using humic acid (for NOM) and kaolin clay (for turbidity). PACl (Poly aluminium chloride) was used as a coagulant. The expression of attachment efficiency has been modified to include the interactions of humic acid (HA) and kaolin, which were not previously accounted for in the model. The coverage functions were used to calculate the attachment efficiency of HA-PACl and PACl-Clay. The standalone coverage function ГPACl-HA efficiently predicted the doses where the removal efficiency was maximum. However, the coverage function ГClay-PACl was impacted by the hydrodynamic conditions in SBC and over-speculated the Clay-PACl interactions. The RMSE value was low for the modified equation indicating that in SBC the interactions between the organic and inorganic impurities are significant. The HA-Kaolin interactions were found to be significant in the modified model in case of a low HA range of 4 and 8 mg/L of HA.

Newer magnetic resonance imaging techniques in neurocysticercosis.

INTRODUCTION: The definitive diagnosis of neurocysticercosis continues to be challenging. We evaluate the role of newer magnetic resonance imaging techniques including constructive interference in steady state, susceptibility-weighted imaging, arterial spin labelling and magnetic resonance spectroscopy in the diagnosis of neurocysticercosis. AIMS AND OBJECTIVES: To study the utility of newer magnetic resonance imaging sequences in the diagnosis of neurocysticercosis. PATIENTS AND METHODS: Eighty-five consecutive patients with neurocysticercosis attending a tertiary care hospital and teaching centre in northern India were included in the study. The diagnosis of neurocysticercosis was made by the Del Brutto criteria. All patients received treatment according to standard guidelines and were followed at 3-month intervals. The following magnetic resonance sequences were performed at baseline: T1 and T2-weighted axial sequences; T2 fluid-attenuated inversion recovery axial sequences; diffusion-weighted imaging; susceptibility-weighted imaging; pre and post-contrast T1-weighted imaging; heavily T2-weighted thin sections (constructive interference in steady state); arterial spin labelling (n = 19); and magnetic resonance spectroscopy (n = 24). RESULTS: The mean (±SD) age was 29.4 ± 12.9 years and 76.5% were men. Seizures were the commonest symptom (89.4%) followed by headache (24.3%), encephalitis (9.4%) and raised intracranial pressure (9.4%). Scolex could be visualised in 43.7%, 55.5% and 61.2% of neurocysticercosis patients using conventional, susceptibility-weighted angiography and constructive interference in steady state imaging sequences, respectively. Susceptibility-weighted angiography and constructive interference in steady state images resulted in significantly higher (P < 0.01) visualisation of scolex compared to conventional sequences. CONCLUSION: Newer magnetic resonance imaging modalities have a lot of promise for improving the radiological diagnosis of neurocysticercosis.

The Eye Opener: Finding and Targeting the Midbrain Lesion.

Lesions of the central nucleus of the third cranial nerve in midbrain leads to bilateral ptosis. We present a case of a 14 year old boy, who was found to have B/L non-correctable ptosis and medial rectus palsy. There was a ring enhancing lesion in the midbrain in contrast MRI which resolved with treatment. The case exemplifies that bilateral ptosis results from the central nucleus involvement of third nerve which has bilateral innervation.

Flexible and Robust Piezoelectric Polymer Nanocomposites Based Energy Harvesters.

Environment friendly, flexible, and robust sensors have attracted considerable research attention due to their potential for a wide range of devices in energy generation and harvesting, sensing, and biomedical applications. In this manuscript, we demonstrate a lead-free, solution processed flexible piezoelectric energy generator based on a nanocomposite film, consisting of MgO nanoparticles of sizes around <50 nm, embedded in poly(vinylidene difluoride) [PVDF] and its copolymer with trifluoroethylene, that is, P(VDF-TrFE) matrix. Piezoelectric, ferroelectric, and leakage current measurements made on samples with various concentrations of MgO nanoparticles revealed a dramatic improvement in these characteristics at 2 wt % MgO with nearly 50% increase in the piezoelectric coefficient as compared to pure P(VDF-TrFE), attributed to the preferred conformation of P(VDF-TrFE) chain, improved crystallinity of the P(VDF-TrFE) matrix, and uniform distribution of nanoparticles. Assessment of the interactions between -OH groups attached to MgO surface and P(VDF-TrFE), carried out using Fourier-transform infrared spectroscopy (FTIR), suggested weak van der Waals forces between -OH groups and P(VDF-TrFE) being responsible for the observed improvement. This flexible nanocomposite device exhibits superior energy harvesting performance with over two-times improvement in the voltage output (2 V) compared to device using P(VDF-TrFE) films alone. Along with superior electrical properties, nanocomposites also exhibit excellent endurance against electrical as well as mechanical fatigue, with piezoelectric coefficient remaining unchanged even after 10 000 bending cycles, supporting their suitability in flexible energy harvesting applications.

Progressive myoclonic epilepsy and horizontal gaze palsy: a rare aetiology.

Gaucher's disease is a rare autosomal recessive, potentially fatal disorder but most common type among lysosomal storage disorders. The disease's incidence is around 1/40 000 to 1/60 000 births in the general population. A 32-year-old man, born out of non-consanguineous union, presented with generalised tonic-clonic seizures and myoclonus since 17 years of age. Seizures were noted to be resistant to multiple epileptic drugs. He developed gait imbalance, intentional tremor and dysarthria. Detailed examination revealed hepatosplenomegaly, bilateral pancerebellar signs with normal power, reflexes and sensory system. He had major cognitive impairment with impaired frontal and temporal lobar functions. Bone marrow evaluation revealed Gaucher cells, confirming the diagnosis.

Cerebellar ataxia due to Leptospirosis- a case report.

BACKGROUND: Leptospirosis involves nervous system in around 10-15% of the cases, the commonest presentation being aseptic meningitis. Most of the clinical features of neuroleptospirosis are due to capillary endothelial damage and vasculitis. Ataxia is an extremely uncommon manifestation of Leptospirosis occuring in <5% of cases. CASE PRESENTATION: A 28 year old female from North India presented with a short febrile illness followed by an acute onset cerebellar ataxia, anemia, thrombocytopenia and transaminitis. Leptospira serology showed high titres of IgM (ELISA) and MAT (microscopic agglutination test titre >1:800) . She was treated with intravenous ceftriaxone for 14 days following which she showed marked recovery. CONCLUSION: The clinical features of neuroleptospirosis are varied, most of them resulting from endothelial damage and vasculitis. Immune mediated phenomenon with no structural damage is another possible mechanism leading to cerebellar ataxia. Cerebellar ataxia due to common tropical infections should be ruled out in the appropriate setting, as early institution of treatment can abate neurological morbidity. The case report highlights the importance of identifying a reversible cause of cerebellar ataixa due to a tropical infection, possibly due to a immune mediated phenomenon, and would be of interest to both internists and neurologists.