In Situ Quantification Of Silver Nanoparticle Dissolution Kinetics In Simulated Sweat Using Linear Sweep Stripping Voltammetry

Linear sweep stripping voltammetry (LSSV) is demonstrated as a sensitive, rapid, and cost-efficient analytical technique for the quantification of silver nanoparticle (AgNP) dissolution rates in simulated sweat. LSSV does not require the extensive sample preparation (e.g., ultrafiltration or centrifugation) needed by more commonly employed techniques, such as atomic spectroscopy. The limit of detection (LOD) of Ag(I)(aq) was 14 ± 6 μg L–1, and measured dissolution rate constants, kdissolution, varied from 0.0168–0.1524 h–1, depending on solution conditions. These values are comparable and agree well with those determined by others in the literature using atomic spectroscopy. Importantly, LSSV had the necessary sensitivity to distinguish the effects of SSW solution conditions on AgNP dissolution rates. Specifically, enhanced dissolution rates were observed with decreased pH and with increased NaCl concentration. The colloidal stability of AgNPs in SSW solutions was also characterized using dynamic light scattering (DLS), ζ potential, and quantitative UV–vis spectroscopy measurements. An increase in AgNP aggregation rate was observed with increased NaCl concentration in SSW, suggesting that the enhancement in AgNP dissolution is driven by the large Cl/Ag ratio, even as the AgNPs undergo significant aggregation

Temperature dependent interaction of hydrogen with PdAg nanocomposite thin films revealed by in-situ synchrotron XRD

PdAg nanocomposite alloy thin films were synthesized using a DC magnetron sputtering process to study the structural changes that occur in the alloy film during the process of hydrogenation and dehydrogenation at different temperatures. The atomic composition of the nano-composite film is 88 at % Pd and 12% at Ag, as determined by the EDAX analysis. In-situ synchrotron X-ray diffraction (XRD) has been used to monitor the subtle structural changes that occurred throughout the hydrogenation and dehydrogenation cycles at an interval of 10 s. This aspect has not been addressed so far. In-situ XRD studies reveal that the XRD peak shifts towards a lower angle due to the lattice expansion in the alloy due to hydrogenation. The change in peak shift is found to be different for different temperatures. The present study also shows no hysteresis during the hydrogen absorption and desorption processes. In addition, the results show that (i) the phase segregation has been observed at 250 , (ii) the peak shift during the hydrogenation process at higher temperatures is not significant, whereas the peak shift throughout the process is more rapid and pronounced at ambient temperature

In-situ investigation on hydrogenation-dehydrogenation of Pd–Ag alloy films

The present work reports on synthesis of PdeAg nano-composite films by magnetron cosputteringand the structural changes in the alloy film during hydrogenation and dehydrogenation.Synchrotron X-ray diffraction is employed in-situ to reveal subtle structuralchanges occurring during hydrogenation and dehydrogenation processes, an aspect notinvestigated so far. It is revealed that the nanocomposite film having 88 at% Pd shows theformation of a-phase as an intermediate phase, however, completion of the hydrogenationprocess yields only b-phase. No b-phase formation is observed in nanocomposite thin filmcontaining 54 at% of Pd, suggesting the suppression of formation of b-phase with increasein Ag concentration. On dehydrogenation, the peak returns to its original position i.e. thevalue before hydrogenation. The data also demonstrated that the addition of Ag in Pd resultsin complete removal of dissolved hydrogen thereby eliminates the problem of hysteresis.The study shows that the lower concentrations of Ag in Pd are better in terms ofextent of peak-shift on hydrogenation/dehydrogenation and faster response/recoverykinetics

Asia–Pacific association for study of liver guidelines on management of ascites in liver disease

The development of ascites is a landmark event in the natural history of cirrhosis. This guidance statement by the Asia–Pacific Association for Study of Liver (APASL) provides an evidence-based approach to managing ascites and its complications in patients with chronic liver disease. These guidelines extensively review the differential diagnosis, diagnostic evaluation, and management of ascites, hyponatremia, hepatic hydrothorax and hepatorenal syndrome (HRS) in patients with cirrhosis and acute-on-chronic liver failure (ACLF). A panel of international experts was invited to formulate the guidelines. The opinions of the experts were collected using two sets of Delphi questionnaires. Then, an online meeting of all the experts was held to discuss the evidence and formulate the final recommendations by consensus. The guidelines were developed using the GRADE system for analysing the level of evidence and strength of recommendation (Table 1). All authors have gone through the guidance document and endorse the same.In this document, we have also covered the grey areas which have been underexplored in previous guidelines and some of the issues which are relatively peculiar to the Asia–Pacific region. Given the high burden of tuberculosis in some of the countries of the Asia–Pacific region, mixed ascites is not uncommon in these patients with liver disease. We discuss the diagnostic approach to mixed ascites and the role of ascitic fluid adenosine deaminase (ADA) and other tests for tuberculosis. In addition, many countries in the Asia–Pacific region are low-middle-income countries, and financial constraints are an essential barrier to liver transplants and other costly therapies like albumin. Hence, we have discussed the role of low-dose albumin in the prevention of paracentesis-induced circulatory dysfunction (PICD) after large-volume paracentesis (LVP) and the prevention of acute kidney injury (AKI) in patients with spontaneous bacterial peritonitis (SBP). We have also reviewed the current evidence of outpatient albumin in managing patients with ascites and have made practical recommendations. We also highlight the timing of albumin infusion concerning LVP. To decrease adverse events and improve patient compliance with diuretic therapy, the guidelines emphasize initiating low-dose diuretics and gradually increasing the dose to the maximum tolerable dose. Non-alcoholic fatty liver disease (NAFLD), also referred to as Metabolic associated fatty liver disease (MAFLD) by some societies has become a significant cause of chronic liver disease worldwide [1]. Many patients with NAFLD/MAFLD related cirrhosis are on angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) when they present to a hepatologist or gastroenterologist with ascites. For the first time, we provide guidance statements regarding the use of these drugs in patients with cirrhosis and ascites. For refractory ascites, we have now defined renal dysfunction following the International Club of Ascites (ICA) recommendations on AKI. Lastly, we have highlighted the gaps in our knowledge and have provided directions for future research

The microbe-derived short-chain fatty acids butyrate and propionate are associated with protection from chronic GVHD

Studies of the relationship between the gastrointestinal microbiota and outcomes in allogeneic hematopoietic stem cell transplantation (allo-HCT) have thus far largely focused on early complications, predominantly infection and acute graft-versus-host disease (GVHD). We examined the potential relationship of the microbiome with chronic GVHD (cGVHD) by analyzing stool and plasma samples collected late after allo-HCT using a case-control study design. We found lower circulating concentrations of the microbe-derived short-chain fatty acids (SCFAs) propionate and butyrate in day 100 plasma samples from patients who developed cGVHD, compared with those who remained free of this complication, in the initial case-control cohort of transplant pa-tients and in a further cross-sectional cohort from an independent transplant center. An additional cross-sectional patient cohort from a third transplant center was analyzed; however, serum (rather than plasma) was available, and the differences in SCFAs observed in the plasma samples were not recapitulated. In sum, our findings from the primary case-control cohort and 1 of 2 cross-sectional cohorts explored suggest that the gastrointestinal microbiome may exert immuno-modulatory effects in allo-HCT patients at least in part due to control of systemic concentrations of microbe-derived SCFAs