Clay minerals identification in rock varnish by XRD: A one-step reduction approach.

Rock varnishes are known to be fine, dark, glossy submicron films found in deserts bare rock surfaces. The oxides and hydroxides of manganese and iron bind together the clay minerals present in the varnish layer. The processes of oxide-hydroxide accumulation at varnish sites are due to iron and manganese oxidizing bacteria which may require clay minerals for additional nutrition. Quantification and identification of clay minerals in this biofilm is needed to understand its formation. Past attempts to analyze the mineralogical composition of rock varnish have led to inconclusive results as varnish is a submicron thin layer composed of a complex mineral matrix. The elimination of non-crystalline cementing groups comprising of free iron oxides is a key step in the identification of many types of clay minerals, particularly in soil/sediment mineral studies.•The Fe-Mn oxide-hydroxide coatings, acting as cementing materials, can be easily removed using a one-step reduction method employing Na2S2O4 at 70 °C, leading to separation of clay minerals.•We have taken the lead from earlier reported Jackson (1958) method, wherein a combination of reagents was used such as sodium acetate, sodium citrate, hydrogen peroxide, sodium bicarbonate, and sodium dithionite for removing carbonate, organic carbon and Fe-Mn oxy-hydroxide coatings respectively from sediment grains to segregate individual grains from each other.•Our modification helps in the unveiling of clay minerals from a solid substrate and reports the X-ray diffraction peaks, which are elsewise hard to detect and therefore earlier studies are inconclusive.

Validation of expert system enhanced deep learning algorithm for automated screening for COVID-Pneumonia on chest X-rays

The coronavirus disease of 2019 (COVID-19) pandemic exposed a limitation of artificial intelligence (AI) based medical image interpretation systems. Early in the pandemic, when need was greatest, the absence of sufficient training data prevented effective deep learning (DL) solutions. Even now, there is a need for Chest-X-ray (CxR) screening tools in low and middle income countries (LMIC), when RT-PCR is delayed, to exclude COVID-19 pneumonia (Cov-Pneum) requiring transfer to higher care. In absence of local LMIC data and poor portability of CxR DL algorithms, a new approach is needed. Axiomatically, it is faster to repurpose existing data than to generate new datasets. Here, we describe CovBaseAI, an explainable tool which uses an ensemble of three DL models and an expert decision system (EDS) for Cov-Pneum diagnosis, trained entirely on datasets from the pre-COVID-19 period. Portability, performance, and explainability of CovBaseAI was primarily validated on two independent datasets. First, 1401 randomly selected CxR from an Indian quarantine-center to assess effectiveness in excluding radiologic Cov-Pneum that may require higher care. Second, a curated dataset with 434 RT-PCR positive cases of varying levels of severity and 471 historical scans containing normal studies and non-COVID pathologies, to assess performance in advanced medical settings. CovBaseAI had accuracy of 87% with negative predictive value of 98% in the quarantine-center data for Cov-Pneum. However, sensitivity varied from 0.66 to 0.90 depending on whether RT-PCR or radiologist opinion was set as ground truth. This tool with explainability feature has better performance than publicly available algorithms trained on COVID-19 data but needs further improvement.

Anaemia and transfusion triggers in critically ill patients - What we have learnt thus far.

Anaemia is a common finding in critically ill patients, the cause of which is multi-factorial including: sepsis, haemolysis (and disseminated intravascular coagulation), iatrogenic blood loss secondary to laboratory sampling, post-operative anaemia, bone marrow suppression/failure, decreased production of erythropoietin, anaemia secondary to drugs/toxins, overt or occult blood loss, functional iron deficiency, poor nutrition and haemodilution. Anaemia is associated with deleterious outcomes including increased risk of cardiac-related morbidity and mortality and decrease in oxygen-carrying capacity in the face of increased metabolic demands. There is a growing body of evidence, which demonstrates that packed red blood cell transfusions are associated with poorer outcomes. Clinicians therefore need to weigh the potential benefit of treating anaemia against the desire to avoid unnecessary transfusions. We explored current literature regarding transfusion triggers and morbidity and mortality associated with packed red blood cell transfusions transfusion, concentrating on studies that have been conducted in critical care patients. In addition, we reflected on trials which considered the viability of iron transfusion and erythropoietin in critically unwell patients.

Neurogenic pathways in remote ischemic preconditioning induced cardioprotection: Evidences and possible mechanisms.

Remote ischemic preconditioning (RIPC) is an intrinsic phenomenon whereby 3~4 consecutive ischemia-reperfusion cycles to a remote tissue (noncardiac) increases the tolerance of the myocardium to sustained ischemiareperfusion induced injury. Remote ischemic preconditioning induces the local release of chemical mediators which activate the sensory nerve endings to convey signals to the brain. The latter consequently stimulates the efferent nerve endings innervating the myocardium to induce cardioprotection. Indeed, RIPC-induced cardioprotective effects are reliant on the presence of intact neuronal pathways, which has been confirmed using nerve resection of nerves including femoral nerve, vagus nerve, and sciatic nerve. The involvement of neurogenic signaling has been further substantiated using various pharmacological modulators including hexamethonium and trimetaphan. The present review focuses on the potential involvement of neurogenic pathways in mediating remote ischemic preconditioning-induced cardioprotection.

Sequestration of dyes from artificially prepared textile effluent using RSM-CCD optimized hybrid backbone based adsorbent-kinetic and equilibrium studies.

Present work reports the synthesis of semi-Interpenetrating Network Polymer (semi-IPN) using Gelatin-Gum xanthan hybrid backbone and polyvinyl alcohol in presence of l-tartaric acid and ammonium persulphate as the crosslinker-initiator system. Reaction parameters were optimized with Response Surface Methodology (RSM) in order to maximize the percent gel fraction of the synthesized sample. Polyvinyl alcohol, l-Tartaric acid, ammonium persulphate, reaction temperature, time and pH of the reaction medium were found to make an impact on the percentage gel fraction obtained. Incorporation of polyvinyl alcohol chains onto hybrid backbone and crosslinking between the different polymer chains were confirmed through techniques like FTIR, SEM-EDX and XRD. Semi-IPN was found to be very efficient in the removal of cationic dyes rhodamine-B (70%) and auramine-O (63%) from a mixture with an adsorbent dose of 700 mg, initial concentration of rhodamine-B 6 mgL-1 and auramine-O 26 mgL-1, at an time interval of 22-25 h and 30 °C temp. Further to determine the nature of adsorption Langmuir and Freundlich adsorption isotherm models were studied and it was found that Langmuir adsorption isotherm was the best fit model for the removal of mixture of dyes. Kinetic studies for the sorption of dyes favored the reaction mechanism to occur via a pseudo second order pathway with R2 value about 0.99.

Neurogenic pathways in remote ischemic preconditioning induced cardioprotection: Evidences and possible mechanisms

Remote ischemic preconditioning (RIPC) is an intrinsic phenomenon whereby 3~4 consecutive ischemia-reperfusion cycles to a remote tissue (noncardiac) increases the tolerance of the myocardium to sustained ischemiareperfusion induced injury. Remote ischemic preconditioning induces the local release of chemical mediators which activate the sensory nerve endings to convey signals to the brain. The latter consequently stimulates the efferent nerve endings innervating the myocardium to induce cardioprotection. Indeed, RIPC-induced cardioprotective effects are reliant on the presence of intact neuronal pathways, which has been confirmed using nerve resection of nerves including femoral nerve, vagus nerve, and sciatic nerve. The involvement of neurogenic signaling has been further substantiated using various pharmacological modulators including hexamethonium and trimetaphan. The present review focuses on the potential involvement of neurogenic pathways in mediating remote ischemic preconditioning-induced cardioprotection.

A case of pulmonary fibrosis associated with rheumatoid arthritis, scleroderma sine scleroderma and ANCA associated vasculitis.

INTRODUCTION: Diffuse parenchymal lung disease (DPLD) may be idiopathic or may be due to known associations such as autoimmune diseases. The prognosis in cases associated with autoimmune diseases depends on many factors such as histopathology, baseline lung function, auto-antibody level, et cetera. DPLD and its prognosis is worse in patients with overlap syndromes. CASE DESCRIPTION: We present a rare case of a 71 year old Caucasian lady with gradually worsening pulmonary fibrosis secondary to an overlap syndrome with rheumatoid arthritis (RA), scleroderma sine scleroderma (SSS) and anti neutrophil cytoplasmic antibody (ANCA) associated vasculitis. DISCUSSION AND EVALUATION: In this paper, we share information from review of literature regarding DPLD associated with RA, systemic sclerosis (SSc) and ANCA associated vasculitis. Details of our discussion include prognostic factors, histology and radiographic features of these individual disease entities. CONCLUSION: Since pulmonary fibrosis in overlap syndromes has a poor prognosis, extensive work up should be performed even when clinical evidence of only one autoimmune disease is present.

Solitary versus shock wave acceleration in laser-plasma interactions.

The excitation of nonlinear electrostatic waves, such as shock and solitons, by ultraintense laser interaction with overdense plasmas and related ion acceleration are investigated by numerical simulations. Stability of solitons and formation of shock waves is strongly dependent on the velocity distribution of ions. Monoenergetic components in ion spectra are produced by "pulsed" reflection from solitary waves. Possible relevance to recent experiments on "shock acceleration" is discussed.