Synthesis and Characterization of Silver Nanoplates by a Seed-mediated Method

Silver nanoplates (SNPs) having different size were synthesized by a seed-mediated method. The seeds -silver nanoparticles with 4 – 6 nm diameters were synthesized first by reducing silver nitrate with sodium borohydride in the present of Trisodium Citrate and Hydrogen peroxide. Then these seeds were developed by continue reducing Ag$^+$ ions with various amount of L-Ascorbic acid to form SNPs. Our analysis showed that the concentratrion of L-Ascorbic acid, a secondary reducing agent, played an important role to form SNPs. In addition, the size and in-plane dipole plasmon resonance wavelenght of silver nanoplates were increased when the concentration of added silver nitrate increased. The characterization of SNPs were studied by UV-Vis, FE-SEM, EDS and TEM methods

Transport Jc in Bulk Superconductors: A Practical Approach?

The characterisation of the critical current density of bulk high temperature superconductors is typically performed using magnetometry, which involves numerous assumptions including, significantly, that Jc within the sample is uniform. Unfortunately, magnetometry is particularly challenging to apply where a local measurement of Jc across a feature, such as a grain boundary, is desired. Although transport measurements appear to be an attractive alternative to magnetization, it is extremely challenging to reduce the cross-sectional area of a bulk sample sufficiently to achieve a sufficiently low critical current that can be generated by a practical current source. In the work described here, we present a technique that enables transport measurements to be performed on sections of bulk superconductors. Metallographic techniques and resin reinforcement were used to create an I-shaped sample of bulk superconductor from a section of Gd-Ba-Cu-O containing 15 wt % Ag2O. The resulting superconducting track had a cross-sectional area of 0.44 mm2. The sample was found to support a critical current of 110 A using a field criterion in the narrowed track region of 1 μV cm-1. We conclude, therefore, that it is possible to measure critical current densities in excess of 2.5 x 108 A m-2 in sections of a bulk superconductor.This work was supported by the Engineering and Physical Sciences Research Council, via a Doctoral Training Award (grant number is EP/L504920/1) and funding from grant number EP/K02910X/1. This work was also supported by the Boeing Company. All data are provided in full in the results section of this paper.This is the author accepted manuscript. The final version is available from IEEE via http://dx.doi.org/10.1109/TASC.2016.253764

Poloxamer additive as luminal surface modification to modulate wettability and bioactivities of small-diameter polyurethane/polycaprolactone electrospun hollow tube for vascular prosthesis applications

In regard of engineering small-diameter vascular graft, a stable surface treatment targeting only the tube lumen toward rapid endothelialization and anti-thrombosis without weakening or deconstructing the prosthesis remains a technical challenge. In this study, a bilayer hollow tube with a hydrophilic inner layer polyurethane/polycaprolactone/Poloxamer (PU/PCL/Poloxamer) was fabricated. Poloxamer 407 was blended with PU/PCL as a one-step surface modification to enhance the hydrophilicity and bioactive properties of the electrospun tube’s luminal surface. Hydrophobic polypropylene glycol backbones anchored poloxamer onto based polymer while hydrophilic side chains migrated to the surface to modify the behaviors of electrospun inner surface. The poloxamer blended surface, interestingly, exhibited complicated attraction and repellent behaviors regulated by the dynamic of PEG chains. Moderate grafting density (2 %–8 %) exhibited high bioactive performance of PEG tails to simultaneously modulate cells' adhesion, elongation and proliferation while restricting platelet adhesion in comparison with PU/PCL and super-hydrophilic PU/PCL/Poloxamer surface. The elevation of poloxamer content in composition resulted in a corresponding increase in both hydrophilicity and tensile strength while maintained the homogenous fibrous structure of electrospun mat. Besides, a hydrophobic outer layer PU/PCL was fabricated to prevent the leakage and permeable transmembrane phenomenon toward the sustain application in vascular engineering

Photochemical Synthesis of Silver Nanodecahedrons under Blue LED Irradiation and Their SERS Activity

Silver nanodecahedrons were successfully synthesized by a photochemical method under irradiation of blue light-emitting diodes (LEDs). The formation of silver nanodecahedrons at different LED irradiation times (0–72 h) was thoroughly investigated by employing different characterization methods such as ultraviolet–visible spectroscopy (UV–Vis), transmission electron microscopy (TEM), and Raman spectroscopy. The results showed that silver nanodecahedrons (AgNDs) were formed from silver nanoseeds after 6 h of LED irradiation. The surface-enhanced Raman scattering (SERS) effects of the synthesized AgNDs were also studied in comparison with those of spherical silver nanoparticles in the detection of 4-mercapto benzoic acid. Silver nanodecahedrons with a size of 48 nm formed after 48 h of LED irradiation displayed stronger SERS properties than spherical nanoparticles because of electromagnetic enhancement. The formation mechanism of silver nanodecahedrons is also reported in our study. The results showed that multihedral silver nanoseeds favored the formation of silver nanodecahedrons

Enhanced hyaluronic acid production from Priestia flexa N7 isolates

Background: Hyaluronic acid (HA) is a gel-like substance made up of glucuronic acid and N-acetylglucosamine units, capable of absorbing and retaining water, present in hydrated gel form across human and animal tissues. It aids in joint lubrication and moisture retention and acts as a cushion for shock absorption. HA has unique biological properties, promoting fibroblast cell growth, aiding wound healing, and exhibiting low solubility and viscosity, making it an organic ingredient in tissue culture techniques. It is utilized in eye drops and skin ointments and plays a vital role in the extracellular matrix, rendering it invaluable in medical and cosmetic applications, such as treating osteoarthritis and enhancing skin wound recovery. Methods: The methods employed in this study involve isolating microorganisms, screening bacterial strains capable of synthesizing HA, identifying bacteria using molecular biological methods, and researching optimal conditions to select bacterial strains that produce the highest HA concentrations. Results: In this study, strain Priestia flexa N7 was studied for suitable conditions for HA biosynthesis. Bacterial strains were fermented for 48 h on medium containing the following ingredients: glucose (60 g/L); yeast extract (5.0 g/L); peptone (20 g/L); K2HPO4 (2.0 g/L); Na2HPO4 (1.0 g/L); NaCl (2.0 g/L); FeSO4 (1.0 g/l); sodium glutamate (9.0 g/L); and MgSO4.7H2O (2.0 g/L) and pH 8.0 at 37°C under the condition of continuous shaking at 150 rpm. The maximum HA production achieved was 1105 mg/L. Conclusions: The mentioned bacterial strain exhibits significant potential for HA synthesis and is extensively employed in producing items across the health care, medical, food, and cosmetic industries. These findings revealed the most effective HA acid manufacturing strategy for achieving maximum output

The efficacy of silver‐based electrospun antimicrobial dressing in accelerating the regeneration of partial thickness burn wounds using a porcine model

(1) Background: Wounds with damages to the subcutaneous are difficult to regenerate because of the tissue damages and complications such as bacterial infection. (2) Methods: In this study, we created burn wounds on pigs and investigated the efficacy of three biomaterials: polycaprolactone‐gelatin‐silver membrane (PCLGelAg) and two commercial burn dressings, Aquacel® Ag and UrgoTul™ silver sulfadiazine. In vitro long‐term antibacterial property and in vivo wound healing performance were investigated. Agar diffusion assays were employed to evaluate bacterial inhibition at different time intervals. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and time‐kill assays were used to compare antibacterial strength among samples. Second‐degree burn wounds in the pig model were designed to evaluate the efficiency of all dressings in supporting the wound healing process. (3) Results: The results showed that PCLGelAg membrane was the most effective in killing both Gram‐positive and Gram-negative bacteria bacteria with the lowest MBC value. All three dressings (PCLGelAg, Aquacel, and UrgoTul) exhibited bactericidal effect during the first 24 h, supported wound healing as well as prevented infection and inflammation. (4) Conclusions: The results suggest that the PCLGelAg membrane is a practical solution for the treatment of severe burn injury and other infection‐related skin complications.</p

Providing Impetus, Tools, and Guidance to Strengthen National Capacity for Antimicrobial Stewardship in Viet Nam

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Location, speciality, and type of the 16 participating hospitals in the VINARES project.

<p>Location, speciality, and type of the 16 participating hospitals in the VINARES project.</p

A timeline to illustrate the conception and implementation of the VINARES project.

<p>GARP, Global Antibiotic Resistance Partnership; LiU, Linköping University; OUCRU, Oxford University Clinical Research Unit; UK NEQAS, United Kingdom National External Quality Assessment Service.</p

Drivers of antibiotic resistance, hospital-related WHO policy package priorities, and how these are met by the VINARES project [10].

<p>Drivers of antibiotic resistance, hospital-related WHO policy package priorities, and how these are met by the VINARES project <a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001429#pmed.1001429-Leung1" target="_blank">[10]</a>.</p