Visible light photodegradation of 2,4-dichlorophenol using nanostructured NaBiS2: Kinetics, cytotoxicity, antimicrobial and electrochemical studies of the photocatalyst.

Removal of the hazardous and endocrine-disrupting 2,4-dichlorophenol (2,4-DCP) from water bodies is crucial to maintain the sanctity of the ecosystem. As a low bandgap material (1.37 eV), NaBiS2 was hydrothermally prepared and used as a potential photocatalyst to degrade 2,4-DCP under visible light irradiation. NaBiS2 appeared to be highly stable and remained structurally undeterred despite thermal variations. With a surface area of 6.69 m2/g, NaBiS2 has enough surface-active sites to adsorb the reactive molecules and exhibit a significant photocatalytic activity. In alkaline pH, the adsorption of 2,4-DCP on NaBiS2 appeared to decrease whereas, the acidic and neutral environments favoured the degradation. An increase in the photocatalyst dosage enhanced the degradation efficiency from 81 to 86 %, because of higher vacant adsorbent sites and the electrostatic attraction between NaBiS2 and 2,4-DCP. The dominant scavengers degraded 2,4-DCP by forming a coordination bond between chlorine's lone pair of electrons and the vacant orbitals of bismuth, following the order hole> OH > singlet oxygen. Being non-toxic to both natural and aquatic systems, NaBiS2 exhibits antifungal properties at higher concentrations. Finally, the electron-rich NaBiS2 is an excellent electrocatalyst that effectively degrades organic pollutants and is a promising material for industrial and environmental applications.

Early-stage culprit in protein misfolding diseases investigated using electrochemical parameters: New insights over peptide-membrane interactions.

The dysfunctioning of ß-cells caused by the unspecific misfolding of the human islet amyloid polypeptide (hIAPP) at the membrane results in type 2 diabetes mellitus. Here, we report for the first time, the early-stage interaction of hIAPP oligomers on the DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) lipid membrane using electrochemical parameters. Electrochemical techniques are better than other techniques to detect hIAPP at significantly lower concentrations. The surface level interactions between the peptide (hIAPP) and lipid membrane (DMPC) were investigated using atomic force microscopy (AFM), confocal microscopy (CM) and electrochemical techniques such as Tafel polarization, cyclic voltammetry (CV), differential pulse voltammetry (DPV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Inserting IAPP into the fluid domains results in breaking the lipid-to-lipid interaction, leading to restriction of membrane mobility. The SLateral values of the liposome and IAPP co-solubilized liposome indicates the cooperative insertion of IAPP. Further, a new method of immobilizing a membrane to the gold surface has been employed, resulting in an electrical contact with the buffer, preventing the direct utilization of a steady-state voltage across the bilayer. The electrochemical studies revealed that the charge transfer resistance decreased for 3-mercaptopropanoic acid modified gold (MPA-Au) electrode coated with the liposome and after the addition of IAPP, followed by an increase in the capacitance. The present study has opened up new dimensions to the understanding of peptide-membrane interactions and shows different experimental approaches for the future researchers in this domain.

Correlation Between Aortic Angulation and Outcomes of Transcatheter Aortic Valve Replacement With New-Generation Valves.

The aim of this study was to assess the correlation of aortic angulation (AA) on immediate postprocedural and long-term outcomes following transcatheter aortic valve replacement (TAVR) with new-generation valves. There is limited and conflicting data on the impact of AA on short- and long-term outcomes in patients undergoing TAVR. Available studies to date were done with first-generation valves. We assessed 179 patients who underwent TAVR with either a balloon-expandable or self-expandable valve at our institute from May 2014 to June 2017 and had multislice computed tomography scans available for AA evaluation. All included patients received a second- or third-generation valve. TAVR endpoints, device success, and adverse events were defined according to the Valve Academic Research Consortium-2 criteria. The mean AA of the study population was 49.05 ± 10.07. Patients were divided into 2 groups: AA <49 and AA ≥49, and then further subdivided by valve type. There were no difference in mean age, The Society for Thoracic Surgery (STS) score, or race distribution between the AA <49 and AA ≥49 groups. The preimplantation balloon valvuloplasty rate was higher in patients with AA ≥ 49 compared to patients with AA <49, (70% vs 55.1%, P = 0.04). There was no difference in re-hospitalization, pacemaker implantation, postprocedural aortic regurgitation or mortality between patients with AA <49 and AA ≥49 irrespective of valve type (P < 0.05). AA does not significantly affect short- or long-term outcomes in patients who undergo TAVR with new-generation balloon-expandable or self-expandable valves.

Aortic Stenosis in African Americans: Focus On Disparities in Treatment and Outcomes.

Aortic stenosis (AS) is the third most common type of cardiovascular disease after hypertension and coronary artery disease, and it carries a high mortality rate when left untreated. Risk factors include male sex, hypertension, tobacco use, advanced age, elevated LDL cholesterol, and coronary atherosclerosis. Definitive treatment for AS includes valve repair, either percutaneously or surgically; however, in aging populations corrective surgery carries increased risk. While research suggests that patients of some non-White ethnic groups, including African-Americans, are less likely than their Caucasian counterparts to have AS, these minority patients may experience may experience differences in the way they receive and accept care. This paper seeks to explicate the mechanisms of racial disparities among the African-Americans affected by aortic stenosis as they pertain to healthcare utilization, referral for valve replacement, acceptance of therapy, and overall treatment outcomes.

Intra-ureteric placement of a urinary catheter in the previously undiagnosed duplex ureter.

We report the inadvertent insertion of a urinary catheter into the upper moiety ureter of a duplex kidney, in a full-term pregnant woman prior to an emergency caesarean section. The patient complained of severe pain during inflation of the catheter balloon. All measures to deflate the balloon and remove the catheter failed. Retrograde ureteric contrast examination showed the placement of the catheter in the proximal part the right upper moiety ureter of a duplex ureter. The catheter was removed with ureteroscopic forceps. We concluded that congenital variation of the urinary tract can complicate a simple catheterisation.

Long-lived photoinduced magnetization in copper-doped ZnSe-CdSe core-shell nanocrystals.

Nanoscale materials have been investigated extensively for applications in memory and data storage. Recent advances include memories based on metal nanoparticles, nanoscale phase-change materials and molecular switches. Traditionally, magnetic storage materials make use of magnetic fields to address individual storage elements. However, new materials with magnetic properties addressable via alternative means (for example, electrical or optical) may lead to improved flexibility and storage density and are therefore very desirable. Here, we demonstrate that copper-doped chalcogenide nanocrystals exhibit not only the classic signatures of diluted magnetic semiconductors--namely, a strong spin-exchange interaction between paramagnetic Cu(2+) dopants and the conduction/valence bands of the host semiconductor--but also show a pronounced and long-lived photoinduced enhancement of their paramagnetic response. Magnetic circular dichroism studies reveal that paramagnetism in these nanocrystals can be controlled and increased by up to 100% when illuminated with above-gap (blue/ultraviolet) light. These materials retain a memory of the photomagnetization for hour-long timescales in the dark, with effects persisting up to ∼80 K.

Nano-engineered electron-hole exchange interaction controls exciton dynamics in core-shell semiconductor nanocrystals.

A strong electron-hole exchange interaction (EI) in semiconductor nanocrystals (NCs) gives rise to a large (up to tens of meV) splitting between optically active ('bright') and optically passive ('dark') excitons. This dark-bright splitting has a significant effect on the optical properties of band-edge excitons and leads to a pronounced temperature and magnetic field dependence of radiative decay. Here we demonstrate a nanoengineering-based approach that provides control over EI while maintaining nearly constant emission energy. We show that the dark-bright splitting can be widely tuned by controlling the electron-hole spatial overlap in core-shell CdSe/CdS NCs with a variable shell width. In thick-shell samples, the EI energy reduces to <250 µeV, which yields a material that emits with a nearly constant rate over temperatures from 1.5 to 300 K and magnetic fields up to 7 T. The EI-manipulation strategies demonstrated here are general and can be applied to other nanostructures with variable electron-hole overlap.