Ab Initio-Based Bond Order Potential for Arsenene Polymorphs Developed via Hierarchical Reinforcement Learning.

Arsenene, a less-explored two-dimensional material, holds the potential for applications in wearable electronics, memory devices, and quantum systems. This study introduces a bond-order potential model with Tersoff formalism, the ML-Tersoff, which leverages multireward hierarchical reinforcement learning (RL), trained on an ab initio data set. This data set covers a spectrum of properties for arsenene polymorphs, enhancing our understanding of its mechanical and thermal behaviors without the complexities of traditional models requiring multiple parameter sets. Our RL strategy utilizes decision trees coupled with a hierarchical reward strategy to accelerate convergence in high-dimensional continuous search spaces. Unlike the Stillinger-Weber approach, which demands separate formalisms for buckled and puckered forms, the ML-Tersoff model concurrently captures multiple properties of the two polymorphs by effectively representing the local environment, thereby avoiding the need for different atomic types. We apply the ML model to understand the mechanical and thermal properties of the arsenene polymorphs and nanostructures. We observe an inverse relationship between the critical strain and temperature in arsenene. Thermal conductivity calculations in nanosheets show good agreement with ab initio data, reflecting a decrease in thermal conductivity attributable to increased anharmonic effects at higher temperatures. We also apply the model to predict the thermal behavior of arsenene nanotubes.

Scope, Safety, and Feasibility of Therapeutic Plasma Exchange in Pediatric Intensive Care Unit: A Single-center Experience.

Background: Indications for therapeutic plasma exchange (TPE) in the pediatric intensive care unit (PICU) are expanding. We aimed to study the demographics, clinical indications, and outcomes of patients who have undergone TPE in our PICU. Materials and methods: This is a retrospective study performed among children aged from 1 month to 16 years of age. Demographics, indications, therapeutic response, serious adverse events (SAE), PICU length of stay (LOS), and death during hospitalization were studied as outcome variables. Results: Therapeutic plasma exchange was performed in 115 sessions on 24 patients for 12 different indications falling under various American Society for Apheresis (ASFA) categories. Therapeutic plasma exchange was performed on ten, four, and ten children for ASFA category I, II, and III indications, respectively. The most common indications were thrombotic microangiopathy (TMA) (8/24) and acute liver failure (ALF) (6/24). During those 115 sessions, a total of five serious adverse events (SAEs) occurred, accounting for 4.3% of the cases. Minor adverse events occurred in 12 sessions (10.4%). Therapeutic response was good in 17 patients (71%) including 5 patients who underwent standard volume TPE (SV-TPE) for ALF. Median PICU LOS was 9 (range 2-120) days. The mortality rate was 12.5% (3/24). Conclusion: Therapeutic plasma exchange is effective in various clinical conditions involving various organ systems. It is an excellent therapeutic modality in children with ALF, irrespective of the exchange volume and TMA. However, SAEs do occur in the minority. How to cite this article: Balasubramanian KK, Venkatachalapathy P, Margabandhu S, Natraj R, Sridaran VK, Lakshmanan C, et al. Scope, Safety, and Feasibility of Therapeutic Plasma Exchange in Pediatric Intensive Care Unit: A Single-center Experience. Indian J Crit Care Med 2023;27(10):766-770.

Faecal metabolite deficit, gut inflammation and diet in Parkinson's disease: Integrative analysis indicates inflammatory response syndrome.

BACKGROUND: Gut-brain axis is widely implicated in the pathophysiology of Parkinson's disease (PD). We take an integrated approach to considering the gut as a target for disease-modifying intervention, using continuous measurements of disease facets irrespective of diagnostic divide. METHODS: We characterised 77 participants with diagnosed-PD, 113 without, by dietary/exogenous substance intake, faecal metabolome, intestinal inflammation, serum cytokines/chemokines, clinical phenotype including colonic transit time. Complete-linkage hierarchical cluster analysis of metabolites discriminant for PD-status was performed. RESULTS: Longer colonic transit was linked to deficits in faecal short-chain-fatty acids outside PD, to a 'tryptophan-containing metabolite cluster' overall. Phenotypic cluster analysis aggregated colonic transit with brady/hypokinesia, tremor, sleep disorder and dysosmia, each individually associated with tryptophan-cluster deficit. Overall, a faster pulse was associated with deficits in a metabolite cluster including benzoic acid and an imidazole-ring compound (anti-fungals) and vitamin B3 (anti-inflammatory) and with higher serum CCL20 (chemotactic for lymphocytes/dendritic cells towards mucosal epithelium). The faster pulse in PD was irrespective of postural hypotension. The benzoic acid-cluster deficit was linked to (well-recognised) lower caffeine and alcohol intakes, tryptophan-cluster deficit to higher maltose intake. Free-sugar intake was increased in PD, maltose intake being 63% higher (p = .001). Faecal calprotectin was 44% (95% CI 5%, 98%) greater in PD [p = .001, adjusted for proton-pump inhibitors (p = .001)], with 16% of PD-probands exceeding a cut-point for clinically significant inflammation compatible with inflammatory bowel disease. Higher maltose intake was associated with exceeding this calprotectin cut-point. CONCLUSIONS: Emerging picture is of (i) clinical phenotype being described by deficits in microbial metabolites essential to gut health; (ii) intestinal inflammation; (iii) a systemic inflammatory response syndrome.

Dynamics of wicking in silicon nanopillars fabricated with interference lithography and metal-assisted chemical etching.

The capillary rise of liquid on a surface, or "wicking", has potential applications in biological and industrial processes such as drug delivery, oil recovery, and integrated circuit chip cooling. This paper presents a theoretical study on the dynamics of wicking on silicon nanopillars based on a balance between the driving capillary forces and viscous dissipation forces. Our model predicts that the invasion of the liquid front follows a diffusion process and strongly depends on the structural geometry. The model is validated against experimental observations of wicking in silicon nanopillars with different heights synthesized by interference lithography and metal-assisted chemical etching techniques. Excellent agreement between theoretical and experimental results, from both our samples and data published in the literature, was achieved.

Isotonic versus hypotonic fluid supplementation in term neonates with severe hyperbilirubinemia - a double-blind, randomized, controlled trial.

AIM: To compare the incidence of hyponatremia in full-term neonates with severe hyperbilirubinemia, receiving intravenous fluid supplementation with 0.2% saline in 5% dextrose versus 0.9% saline in 5% dextrose, to prevent blood exchange transfusion (BET). METHODS: In this double-blind, randomized, controlled trial, full-term newborns (≥37 weeks), appropriate for gestational age, with severe non-haemolytic hyperbilirubinemia (serum bilirubin ≥ 20 mg/dL) were enrolled. Eligible neonates were randomized to receive either 0.2% saline in 5% dextrose (hypotonic fluid group) or 0.9% saline in 5% dextrose (isotonic fluid group) over 8 hrs, in addition to phototherapy. The primary outcome was proportion of neonates developing hyponatremia (serum Na < 135 mmol/L) after 8 h. RESULTS: Forty-two neonates were analysed in each group. Proportion of neonates developing hyponatremia after 8 h was higher in hypotonic fluid group as compared to isotonic fluid group (48.8% vs. 10.5%, p < 0.001). However, a larger proportion in isotonic fluid group developed hypernatremia (39.5% vs. 12.2%, p < 0.001). The rate of BET was similar in both groups. CONCLUSION: In full-term neonates with severe hyperbilirubinemia, administration of hypotonic fluid to prevent BET was associated with a higher incidence of hyponatremia while isotonic fluid was associated with an increased incidence of hypernatremia.

Unusual High Hardness and Load-Dependent Mechanical Characteristics of Hydrogenated Carbon-Nitrogen Hybrid Films.

Mechanical components are exposed to a rigorous environment in a number of applications including engineering, aerospace, and automobiles. Thus, their service lifetime and reliability are always on the verge of risk. Protective coatings with high hardness are required to enhance their service lifetime and minimize the replacement cost and waste burden. Hydrogenated amorphous carbon including nitrogen-incorporated films, that are commonly deposited by plasma-enhanced chemical vapor deposition, are widely used for commercial protective coating applications. However, their mechanical hardness still falls into the moderate hard regime. This needs to be substantially enhanced for advanced applications. Here, we report the synthesis of very hard nanostructured hydrogenated carbon-nitrogen hybrid (n-C:H:N) films. The optimized n-C:H:N film displays a hardness of about 36 GPa, elastic modulus of 360 GPa, and reasonably good elastic recovery (ER) of 62.7%. The mechanical properties of n-C:H:N films are further tailored when nitrogen pressure is tuned during the growth. The realized remarkably improved mechanical properties are correlated with the films' structural properties and experimental growth conditions. We also conducted density functional theory calculations that show the trend for the elastic modulus of the amorphous carbon films with varying nitrogen concentrations matches well with experimentally measured values. Finally, we probed load-dependent mechanical properties of n-C:H:N films and found an anomalous behavior; some of the mechanical parameters, for instance, ER, reveal an irregular trend with indentation load, which we explain in the framework of the film-substrate composite concept. Overall, this work uncovers many unknown and exciting mechanical phenomena that could pave the way for new technological developments.

Neonatal aortic dilatation secondary to vitamin A deficiency.

We report on a term neonate with unexplained respiratory distress, dilatation of the descending aorta, and low serum retinol concentration. The respiratory distress did not respond to conventional medical management and persisted for 22 days requiring an inspired oxygen fraction of 0.4 to 0.5 to maintain adequate arterial oxygen saturation. One week after intramuscular vitamin A therapy, the respiratory distress and requirement for supplementary oxygen resolved. Dilatation of the distal aorta resolved at 7 weeks of age. An association between vitamin A deficiency and aortic dilatation has previously been described in rats, but the association in humans has rarely been reported. We suggest that unexplained neonatal respiratory distress and a dilated aorta should prompt suspicion of vitamin A deficiency. An underlying infective or inflammatory process may give rise to a falsely low serum retinol concentration. Serum retinol and retinol binding protein concentrations in both the mother and infant should be used to guide vitamin A status, treatment, and subsequent response.

The effect of anterior cervical fusion on neck motion.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: To precisely measure the effect of anterior cervical fusion on neck motion. SUMMARY OF BACKGROUND DATA: Anterior cervical decompression and stabilization procedures are successful in treating recalcitrant cervical radiculopathy and cervical myelopathy. Most assume that these "fusion" procedures result in a loss of neck motion, although changes in overall motion following anterior cervical fusion have never been precisely quantified. METHODS: Twenty-five consecutive patients undergoing anterior cervical fusion of one to four levels underwent cervical range of motion testing in three planes using an unconstrained instrumented linkage before surgery and more than 3 months after surgery. These data were compared with that of 10 volunteers with no prior history of neck complaints. Motion data were compared between patients and volunteers, and between the patients before surgery and at last follow-up, using RMANOVA and Fisher's PLSD post hoc test. RESULTS: Before surgery, the patients had significantly less motion than the volunteers in all directions. Following surgical fusion, patients gained a statistically significant amount of motion in all planes, although they did not achieve the motion seen among the volunteers. Gains in motion were seen among all patients, including those undergoing four-level fusions, and there was no correlation between postoperative motion and the number of levels fused. CONCLUSIONS: Patients undergoing anterior cervical fusion have diminished neck motion compared with normal volunteers. Following surgery, they may be expected to gain motion, even when undergoing multilevel fusions. However, these patients are unlikely to regain the neck motion seen among normal individuals without neck complaints.