Scattering states of coupled valence-band holes in point defect potential derived from variable phase theory

In this article we present a method to compute the scattering states of holes in spherical bands in the strong spin-orbit coupling regime. More precisely, we calculate scattering phase shifts and amplitudes of holes induced by defects in a semiconductor crystal. We follow a previous work done on this topic by Ralph [H. I. Ralph, Philips Res. Rept. 32 160 (1977)] to account for the p-wave nature and the coupling of valence band states. We extend Ralph's analysis to incorporate finite-range potentials in the scattering problem. We find that the variable phase method provides a very convenient framework for our purposes and show in detail how scattering amplitudes and phase shifts are obtained. The Green's matrix of the Schroedinger equation, the Lippmann-Schwinger equation and the Born approximation are also discussed. Examples are provided to illustrate our calculations with Yukawa type potentials.Comment: 16 pages and 9 figure

Coulomb singularities in scattering wave functions of spin-orbit-coupled states

We report on our analysis of the Coulomb singularity problem in the frame of the coupled channel scattering theory including spin-orbit interaction. We assume that the coupling between the partial wave components involves orbital angular momenta such that $\Delta l = 0, \pm 2$. In these conditions, the two radial functions, components of a partial wave associated to two values of the angular momentum $l$, satisfy a system of two second-order ordinary differential equations. We examine the difficulties arising in the analysis of the behavior of the regular solutions near the origin because of this coupling. First, we demonstrate that for a singularity of the first kind in the potential, one of the solutions is not amenable to a power series expansion. The use of the Lippmann-Schwinger equations confirms this fact: a logarithmic divergence arises at the second iteration. To overcome this difficulty, we introduce two auxilliary functions which, together with the two radial functions, satisfy a system of four first-order differential equations. The reduction of the order of the differential system enables us to use a matrix-based approach, which generalizes the standard Frobenius method. We illustrate our analysis with numerical calculations of coupled scattering wave functions in a solid-state system

Cytocompatibility of Medical Biomaterials Containing Nickel by Osteoblasts: a Systematic Literature Review

The present review is based on a survey of 21 studies on the cytocompatibility of medical biomaterials containing nickel, as assessed by cell culture of human and animal osteoblasts or osteoblast-like cells. Among the biomaterials evaluated were stainless steel, NiTi alloys, pure Ni, Ti, and other pure metals. The materials were either commercially available, prepared by the authors, or implanted by various techniques to generate a protective layer of oxides, nitrides, acetylides. The observation that the layers significantly reduced the initial release of metal ions and increased cytocompatibility was confirmed in cell culture experiments. Physical and chemical characterization of the materials was performed. This included, e.g., surface characterization (roughness, wettability, corrosion behavior, quantity of released ions, microhardness, and characterization of passivation layer). Cytocompatibility tests of the materials were conducted in the cultures of human or animal osteoblasts and osteoblast-like cells. The following assays were carried out: cell proliferation and viability test, adhesion test, morphology (by fluorescent microscopy or SEM). Also phenotypic and genotypic markers were investigated. In the majority of works, it was found that the most cytocompatible materials were stainless steel and NiTi alloy. Pure Ni was rendered and less cytocompatible. All the papers confirmed that the consequence of the formation of protective layers was in significant increase of cytocompatibility of the materials. This indicates the possible further modifications of the manufacturing process (formation of the passivation layer)

High performance liquid chromatography tandem mass spectrometry dual extraction method for identification of green tea catechin metabolites excreted in human urine

The simultaneous analysis of free-form and conjugated flavonoids in the same sample is difficult but necessary to properly estimate their bioavailability. A method was developed to optimise the extraction of both free and conjugated forms of catechins and metabolites in a biological sample following the consumption of green tea. A double-blind randomised controlled trial was performed in which 26 volunteers consumed daily green tea and vitamin C supplements and 24 consumed a placebo for 3 months. Urine was collected for 24h at 4 separate time points (pre- and post-consumption) to confirm compliance to the supplementation and to distinguish between placebo and supplementation consumption. The urine was assessed for both free and conjugated metabolites of green tea using LC-MS2 analysis, after a combination extraction method, which involved an ethyl acetate extraction followed by an acetonitrile protein precipitation. The combination method resulted in a good recovery of EC-O-sulphate (91±7%), EGC-O-glucuronide (94±6%), EC (95±6%), EGC (111±5%) and ethyl gallate (74±3%). A potential total of 55 catechin metabolites were investigated, and of these, 26 conjugated (with methyl, glucuronide or sulphate groups) and 3 free-form (unconjugated) compounds were identified in urine following green tea consumption. The majority of EC and EGC conjugates significantly increased post-consumption of green tea in comparison to baseline (pre-supplementation) samples. The conjugated metabolites associated with the highest peak areas were O-methyl-EC-O-sulphate and the valerolactones M6/M6'-O-sulphate. In line with previous studies, EC and EGC were only identified as conjugated derivatives, and EGCG and ECG were not found as mono-conjugated or free-forms. In summary, the method reported here provides a good recovery of catechin compounds and is appropriate for use in the assessment of flavonoid bioavailability, particularly for biological tissues that may contain endogenous deconjugating enzymes

Homocysteine Induces Phosphatidylserine Exposure in Cardiomyocytes through Inhibition of Rho Kinase and Flippase Activity.

AIMS: Increased levels of homocysteine (Hcy) form an independent risk factor for cardiovascular disease. In a previous study we have shown that Hcy induced phosphatidylserine (PS) exposure to the outer leaflet of the plasma membrane in cardiomyocytes, inducing a pro-inflammatory phenotype. In the present study the mechanism(s) involved in Hcy-induced PS exposure were analyzed. METHODS: H9c2 rat cardiomyoblasts were subjected to 2.5 mM D,L-Hcy and analyzed for RhoA translocation and activity, Rho Kinase (ROCK) activity and expression and flippase activity. In addition, the effect of ROCK inhibition with Y27632 on Hcy-induced PS exposure and flippase activity was analyzed. Furthermore, GTP and ATP levels were determined. RESULTS: Incubation of H9c2 cells with 2.5 mM D,L-Hcy did not inhibit RhoA translocation to the plasma membrane. Neither did it inhibit activation of RhoA, even though GTP levels were significantly decreased. Hcy did significantly inhibit ROCK activation, but not its expression, and did inhibit flippase activity, in advance of a significant decrease in ATP levels. ROCK inhibition via Y27632 did not have significant added effects on this. CONCLUSION: Hcy induced PS exposure in the outer leaflet of the plasma membrane in cardiomyocytes via inhibition of ROCK and flippase activity. As such Hcy may induce cardiomyocytes vulnerable to inflammation in vivo in hyperhomocysteinaemia patients

Efficacy and safety of oral semaglutide in patients with type 2 diabetes and moderate renal impairment (PIONEER 5): a placebo-controlled, randomised, phase 3a trial

Background: Oral semaglutide is the first oral glucagon-like peptide-1 (GLP-1) receptor agonist for glycaemic control in patients with type 2 diabetes. Type 2 diabetes is commonly associated with renal impairment, restricting treatment options. We aimed to investigate the efficacy and safety of oral semaglutide in patients with type 2 diabetes and moderate renal impairment. Methods: This randomised, double-blind, phase 3a trial was undertaken at 88 sites in eight countries. Patients aged 18 years and older, with type 2 diabetes, an estimated glomerular filtration rate of 30–59 mL/min per 1·73 m2, and who had been receiving a stable dose of metformin or sulfonylurea, or both, or basal insulin with or without metformin for the past 90 days were eligible. Participants were randomly assigned (1:1) by use of an interactive web-response system, with stratification by glucose-lowering medication and renal function, to receive oral semaglutide (dose escalated to 14 mg once daily) or matching placebo for 26 weeks, in addition to background medication. Participants and site staff were masked to assignment. Two efficacy-related estimands were defined: treatment policy (regardless of treatment discontinuation or rescue medication) and trial product (on treatment without rescue medication) in all participants randomly assigned. Endpoints were change from baseline to week 26 in HbA1c (primary endpoint) and bodyweight (confirmatory secondary endpoint), assessed in all participants with sufficient data. Safety was assessed in all participants who received at least one dose of study drug. This trial is registered on ClinicalTrials.gov, number NCT02827708, and the European Clinical Trials Registry, number EudraCT 2015-005326-19, and is now complete. Findings: Between Sept 20, 2016, and Sept 29, 2017, of 721 patients screened, 324 were eligible and randomly assigned to oral semaglutide (n=163) or placebo (n=161). Mean age at baseline was 70 years (SD 8), and 168 (52%) of participants were female. 133 (82%) participants in the oral semaglutide group and 141 (88%) in the placebo group completed 26 weeks on treatment. At 26 weeks, oral semaglutide was superior to placebo in decreasing HbA1c (estimated mean change of −1·0 percentage point (SE 0·1; −11 mmol/mol [SE 0·8]) vs −0·2 percentage points (SE 0·1; −2 mmol/mol [SE 0·8]); estimated treatment difference [ETD]: −0·8 percentage points, 95% CI −1·0 to −0·6;

Wpływ wybranych leków hipotensyjnych na biodostępność składników mineralnych z grochu łuskanego w procesie trawienia enzymatycznego in vitro

Interaction of antihypertensive drugs with minerals can occur during digestion in the digestive tract of patients. The aim of this study was to estimate the influence of hypotensive drugs on the bioavailability of magnesium, iron, zinc and copper from shelled pea during in vitro enzymatic digestion. The degree of release of magnesium, iron, zinc and copper from shelled pea was determined with and without (the control) addition of hypotensive drugs. Four antihypertensive drugs in standard doses (one tablet per sample) were analysed: Metocard (β-blocker), Cardilopin (Ca-antagonist), Apo-perindox (angiotensin-converting-enzyme inhibitor ACE-I) and Indapen (diuretic). The samples were subjected to enzymatic digestion under in vitro conditions. The content of minerals in shelled pea before and after enzymatic digestion was determined by flame atomic absorption spectrometry (AAS). It was found that Indapen (indapamide) significantly decreased the release of magnesium, iron and zinc from shelled pea. The degree of release of magnesium was lower in samples with Metocard (metoprolol) than in the control. The release of copper was significantly reduced by Cardilopin (amlodipine). Indapamide, metoprolol and amlodypine decreased the release of minerals from pea in vitro enzymatic digestion of shelled pea