Experimental and computational studies of a graphene oxide barrier layer covalently functionalized with amino acids on Mg AZ13 alloy in salt medium

Magnesium alloys are promising materials for the biomedical and automobile industries. The Mg alloy''s light-weight property leads to numerous industrial applications. However, the magnesium alloy oxide layers are not stable in salt environments. Organic inhibitors and epoxy coatings fail as long term barriers in such media. Recently, carbon based functionalized materials, graphene oxides, were shown to be promising materials for improving corrosion resistance in acid and salt environments. Our research considered graphene oxide covalently functionalized with the amino acid leucine to form anticorrosion coating materials. The functionalized materials were characterized by XRD, Raman, FESEM, HRTEM, FTIR, and AFM methods. The corrosion inhibition efficiency was monitored by electrochemical methods. The novelty of the functionalized graphene oxide materials is that they are water impermeable, and thus could enhance the anticorrosion resistance in salt environments.

Leucine functionalized graphene oxide chemisorbed on a 111 surface AZ13 magnesium alloy via edge functional groups.     

Role of minimal residual disease monitoring in acute promyelocytic leukemia treated with arsenic trioxide in frontline therapy

Data on minimal residual disease (MRD) monitoring in acute promyelocytic leukemia (APL) are available only in the context of conventional all-trans retinoic acid plus chemotherapy regimens. It is recognized that the kinetics of leukemia clearance is different with the use of arsenic trioxide (ATO) in the treatment of APL. We undertook a prospective peripheral blood RT-PCR-based MRD monitoring study on patients with APL treated with a single agent ATO regimen. A total of 151 patients were enrolled in this study. A positive RT-PCR reading at the end of induction therapy was significantly associated on a multivariate analysis with an increased risk of relapse (relative risk = 4.9; P = .034). None of the good risk patients who were RT-PCR negative at the end of induction relapsed. The majority of the relapses (91%) happened within 3 years of completion of treatment. After achievement of molecular remission, the current MRD monitoring strategy was able to predict relapse in 60% of cases with an overall sensitivity and specificity of 60% and 93.2%, respectively. High-risk group patients and those that remain RT-PCR positive at the end of induction are likely to benefit from serial MRD monitoring by RT-PCR for a period of 3 years from completion of therapy.     

Population pharmacokinetics of cyclophosphamide in patients with thalassemia major undergoing HSCT

CY in combination with BU is a widely used conditioning regimen for haematopoietic SCT (HSCT). The aim of this study was to evaluate the pharmacokinetics (PK) of CY and its major metabolite 4-hydroxyCY (HCY) in patients with thalassemia undergoing HSCT. A total of 55 patients received BU (16 mg/kg) followed by CY (160-200 mg/kg) both over 4 days before HSCT. A population PK model was developed to describe the disposition of CY and HCY and the inter-individual (IIV) and inter-occasion variability (IOV). The model was also used to determine the effects covariates including: demographics, Lucarelli classification and polymorphisms in enzymes involved in the metabolism or biotransformation of CY had on CY and HCY disposition. Overall, 17-114% IIV and 12-103% IOV in CY and HCY PK parameters were observed. Body weight and age were the main covariates, which explained the largest portion of the IIV. In addition, CYP2C9*2 explained a significant portion of the IIV in the clearance (P<0.002) and thus the area under the concentration curve (P<0.05) of CY. This covariate model may be used to design and plan targeted dose therapy in this group of pediatric patients, if clinical outcome association with CY PK are proved and target range established.     

Experimental and DFT studies of porous carbon covalently functionalized by polyaniline as a corrosion inhibition barrier on nickel-based alloys in acidic media

In acidic medium, nickel alloys severely suffer from long term corrosion problems as a result of the breakdown of their passivating oxide. The present study considers polyaniline functionalized fish-scale graphitic carbon as an anticorrosion coating on the nickel alloy surface. The fish-scale porous carbon materials are characterized by XRD, ATR-FITR, UV, Raman, TGA, SS NMR, FESEM, and TEM methods. The surface of the alloy is covalently bound with a polyaniline long chain protonated polymer so that the polyaniline functionalized honeycomb fish-scale carbon structure can exchange electrons with the metal surface. The corrosion inhibition efficiency has been investigated in different acid media like sulfuric acid and hydrochloric acid by electrochemical methods. Polyaniline functionalized porous carbon showed in 1 M H₂SO₄ inhibition efficiency around 64% and in 1 M HCl inhibition efficiency was around 74%. The inhibition efficiency was higher in HCl because chloride ions were not able to penetrate the graphitic sheet. The novelty of this coating is in the fact that the polyaniline functionalized porous carbon has high conductivity and is electrochemically stable in acidic medium. It is able to donate electrons to the polarized metal surface.

Polyaniline functionalized fish scale carbon chemisorption on 111 nickel alloy surface by polyaniline polaron nitrogen free electron.     

A Distributed Model of Carbohydrate Transport and Metabolism in the Liver during Rest and High-Intensity Exercise

A model of reaction and transport in the liver was developed that describes the metabolite concentration and reaction flux dynamics separately within the tissue and blood domains. The blood domain contains equations for convection, axial dispersion, and transport to the surrounding tissue; and the tissue domain consists of reactions representing key carbohydrate metabolic pathways. The model includes the metabolic heterogeneity of the liver by incorporating spatial variation of key enzymatic maximal activities. Simulation results of the overnight fasted, resting state agree closely with experimental values of overall glucose uptake and lactate output by the liver. The incorporation of zonation of glycolytic and gluconeogenic enzyme activities causes the expected increase in glycolysis and decrease in gluconeogenesis along the sinusoid length from periportal to perivenous regions, while fluxes are nearly constant along the sinusoid length in the absence of enzyme zonation. These results confirm that transport limitations are not sufficient to account for the observed tissue heterogeneity of metabolic fluxes. Model results indicate that changes in arterial substrate concentrations and hepatic blood flow rate, which occur in the high-intensity exercise state, are not sufficient to shift the liver metabolism enough to account for the 5-fold increase in hepatic glucose production measured during exercise. Changes in maximal activities, whether caused by exercise-induced changes in insulin, glucagon, or other hormones are shown to be needed to achieve the expected glucose output. This model provides a framework for evaluating the relative importance to hepatic function of various phenomenological changes that occur during exercise. The model can also be used to assess the potential effect of metabolic heterogeneity on metabolism.     

Effect of oropharyngeal colostrum therapy in the prevention of necrotising enterocolitis among very low birthweight neonates: A meta‐analysis of randomised controlled trials

Background

Necrotising enterocolitis (NEC ) is one of the most common life‐threatening emergencies of the gastrointestinal tract in preterm neonates. The present study aimed to determine the efficacy of oropharyngeal colostrum with respect to reducing NEC in preterm neonates.

Methods

A literature search was conducted for various randomised control trials by searching the Cochrane Central Register of Controlled Trials, PubMed, EMBASE and ongoing clinical trials. Randomised or quasi‐randomised trials comparing oropharyngeal colostrum versus placebo in neonates (birthweight ≤ 1500 g or gestational age ≤ 32 weeks) were included in the review. The methodological quality of each trial was independently reviewed by the authors. For categorical and continuous variables, typical estimates for relative risk and typical estimates for weighted mean difference were calculated, respectively. A random effect model was assumed for meta‐analysis.

Results

In total, four eligible trials were included in the review. Oropharyngeal colostrum therapy was not associated with a statistically significant reduction in the incidence of NEC stage ≥2 [typical relative risk (RR ) = 0.64; 95% confidence interval (CI ) = 0.27–1.49], mortality from any cause (typical RR  = 0.86; 95% CI  = 0.15–4.80) and time to reach full feed [typical weighted mean difference (WMD) = ?3.26; 95% CI  = ?8.87 to 2.35]. Duration of hospital stay was significantly less in the control group (typical WMD  = 9.77; 95% CI  = 3.96–15.59).

Conclusions

The current evidence is insufficient for recommending oropharyngeal colostrum as a routine clinical practice in the prevention of NEC . We emphasise the need for large randomised controlled trials with an adequate sample size and validated clinical outcomes in preterm neonates.

     

Sodium chloride or plasmalyte-148 for patients presenting to emergency departments with diabetic ketoacidosis: A nested cohort study within a multicentre,cluster, crossover,randomised, controlled trial

Objective

To test the hypothesis that fluid resuscitation in the ED with plasmalyte-148 (PL) compared with 0.9% sodium chloride (SC) would result in a lower proportion of patients with diabetic ketoacidosis (DKA) requiring intensive care unit (ICU) admission.

Methods

We performed a prespecified nested cohort study at two hospitals within a cluster, crossover, open label, randomised, controlled trial comparing the effects of PL versus SC as fluid therapy for patients who presented to the ED with DKA. All patients presenting within a fixed recruitment period were included. The primary outcome was the proportion of patients admitted to ICU.

Results

Eighty-four patients were enrolled (SC n = 38, PL n = 46). The SC group had a lower median pH on admission (SC: 7.09 [interquartile range (IQR) 7.01–7.21], PL: 7.17 [IQR 6.99–7.26]). The median volume of intravenous fluids administered in ED was 2150 mL (IQR 2000–3200 mL; SC) and 2200 mL (IQR 2000–3450; PL); respectively. A higher proportion of patients in the SC group, 19 (50%), was admitted to ICU compared with PL group, 18 (39.1%); however, after adjustment for pH at presentation and diabetes type in a multivariable logistic regression model, the PL group did not have a significantly different rate of ICU admission compared with the SC group (odds ratio for ICU admission 0.73, 95% confidence interval 0.13–3.97, P = 0.71).

Conclusion

Patients with DKA treated with PL compared with SC in the EDs had similar rates of requiring ICU admission.     

High affinity type I interleukin 1 receptor antagonists discovered by screening recombinant peptide libraries.

Two families of peptides that specifically bind the extracellular domain of the human type I interleukin I (IL-1) receptor were identified from recombinant peptide display libraries. Peptides from one of these families blocked binding of IL-lalpha to the type I IL-1 receptor with IC50 values of 45-140 microM. Affinity-selective screening of variants of these peptides produced ligands of much higher affinity (IC50 approximately 2 nM). These peptides block IL-1-driven responses in human and monkey cells; they do not bind the human type II IL-1 receptor or the murine type I IL-1 receptor. This is the first example (that we know of) of a high affinity peptide that binds to a cytokine receptor and acts as a cytokine antagonist.