FSE–Ag complex NS: preparation and evaluation of antibacterial activity

Silver (Ag) complexes of drugs and their nanosystems have great potential as antibacterials. Recently, an Ag complex of furosemide (Ag–FSE) has shown to be a promising antimicrobial. However, poor solubility of Ag–FSE could hamper its introduction into clinics. Therefore, the authors developed a nanosuspension of Ag–FSE (Ag–FSE_NS) for its solubility and antibacterial activity enhancement. The aim of this study was to introduce a novel nanoantibiotic with enhanced antibacterial efficacy. Ag–FSE_NS was prepared by precipitation–ultrasonication technique. Size, polydispersity index (PI) and zeta potential (ZP) of prepared Ag–FSE_NS were measured by dynamic light scattering, whereas surface morphology was determined using scanning electron microscopy (SEM). In vitro antibacterial activity was evaluated against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa using broth microdilution method. Size, PI and ZP of optimised Ag–FSE_NS1 were 191.2 ± 19.34 nm, 0.465 ± 0.059 and −55.7 ± 8.18 mV, respectively. SEM revealed that Ag–FSE_NS1 particles were rod or needle‐like with smooth surfaces. Saturation solubility of Ag–FSE in NS increased eight‐fold than pure Ag–FSE. Ag–FSE_NS1 exhibited two‐fold and eight‐fold enhancements in activity against E. coli and S. aureus, respectively. The results obtained showed that developed Ag–FSE_NS1 holds a promise as a topical antibacterial.Inspec keywords: nanomedicine, nanofabrication, light scattering, surface morphology, silver, particle size, solubility, suspensions, scanning electron microscopy, electrokinetic effects, drugs, biomedical materials, antibacterial activity, microorganisms, nanoparticles, drug delivery systems, transmission electron microscopyOther keywords: saturation solubility, topical antibacterial, size 171.86 nm to 210.54 nm, voltage ‐47.52 mV to ‐63.88 mV, Ag, broth microdilution method, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, SEM, scanning electron microscopy, surface morphology, dynamic light scattering, particle size, polydispersity index, precipitation–ultrasonication technique, nanoantibiotic, nanosuspension, furosemide, nanosystems, drugs, Ag–FSE_NS preparation, in vitro antibacterial activity, pure Ag–FSE, Ag–FSE_NS1 particles, optimised Ag–FSE_NS1, zeta potential, enhanced antibacterial efficacy, antibacterials     

Substitution of Antimony by Tin and Tellurium in n-Type Skutterudites CoSb2.8Sn x Te0.2−x

We have studied the substitution of antimony by tin and tellurium in n-type skutterudites CoSb_2.8Sn _x Te_0.2?x . The samples were made by ball milling ingots and hot pressing the ball-milled nanopowder. Rather than filling the cage of the structure, we aimed to use disorder in pnictogen rings by elemental substitution of Sb by Sn and Te. In skutterudite CoSb₃, the dominant heat-carrying phonons are associated with the vibrational modes of the Sb-rings; disorder in the rings can be an effective way to suppress the thermal transport. By suitably tuning the contents of Sn and Te in the skutterudites, we have suppressed the thermal conductivity and achieved a power factor of ~42 μW cm^?1 K^?2 at 530°C. A peak thermoelectric figure of merit (ZT) reaches ~1.1 at 530°C for CoSb_2.8Sn_0.005Te_0.195. This ZT value is comparable with that of some of the single-filled skutterudites.     

Preparation and characterization of modified polypropylene by using electron beam irradiation

The modification by electron beam irradiation was applied to polypropylene (PP). In this process it is tried to add low density polyethylene (LDPE) and talc in the blend to check effects on its rheological property and thermal stability. The decrease in T_m could be the result of chain scissioning which decrease the number of tie molecule in the amorphous regions and consequently weakens the laminar connections. LDPE incorporated sample was comparatively better in shear thinning effect, zero shear viscosity, and thermal stability. Power law index, n, was 0.30 and 0.89 for the modified PP with LDPE and pure PP, respectively.     

Preparation of high-entropy carbides by different sintering techniques

Journal of Materials Science - Dense (Hf, Ta, Nb, Ti, V)C- and (Ta, Nb, Ti, V, W)C-based high-entropy carbides (HEC) were produced by three different sintering techniques: gas pressure...     

Creep–Environment Interactions in Dwell-Fatigue Crack Growth of Nickel Based Superalloys

A multi-scale, mechanistic model is developed to describe and predict the dwell-fatigue crack growth rate in the P/M disk superalloy, ME3, as a function of creep–environment interactions. In this model, the time-dependent cracking mechanisms involve grain boundary sliding and dynamic embrittlement, which are identified by the grain boundary activation energy, as well as, the slip/grain boundary interactions in both air and vacuum. Modeling of the damage events is achieved by adapting a cohesive zone (CZ) approach which considers the deformation behavior of the grain boundary element at the crack tip. The deformation response of this element is controlled by the surrounding continuum in both far field (internal state variable model) and near field (crystal plasticity model) regions and the intrinsic grain boundary viscosity which defines the mobility of the element by scaling up the motion of dislocations into a mesoscopic scale. This intergranular cracking process is characterized by the rate at which the grain boundary sliding reaches a critical displacement. A damage criterion is introduced by considering the grain boundary mobility limit in the tangential direction leading to strain incompatibility and failure. Results of simulated intergranular crack growth rate using the CZ model are generated for temperatures ranging from 923 K to 1073 K (650 °C to 800 °C), in both air and vacuum. These results are compared with those experimentally obtained and analysis of the model sensitivity to loading conditions, particularly temperature and oxygen partial pressure, are presented.     

Adapted Delaunay triangulation method for free-form surface generation from random point clouds for stochastic optimization applications

Free-form surfaces are defined with NURBS (non-uniform rational basis spline) for most computer-aided engineering (CAE) applications. The NURBS method requ     

Integration of Palmer Drought Severity Index and remote sensing data to simulate wetland water surface from 1910 to 2009 in Cottonwood Lake area, North Dakota

Spatiotemporal variations of wetland water in the Prairie Pothole Region are controlled by many factors; two of them are temperature and precipitation that form the basis of the Palmer Drought Severity Index (PDSI). Taking the 196 km² Cottonwood Lake area in North Dakota as our pilot study site, we integrated PDSI, Landsat images, and aerial photography records to simulate monthly water surface. First, we developed a new Wetland Water Area Index (WWAI) from PDSI to predict water surface area. Second, we developed a water allocation model to simulate the spatial distribution of water bodies at a resolution of 30 m. Third, we used an additional procedure to model the small wetlands (less than 0.8 ha) that could not be detected by Landsat. Our results showed that i) WWAI was highly correlated with water area with an R² of 0.90, resulting in a simple regression prediction of monthly water area to capture the intra- and inter-annual water change from 1910 to 2009; ii) the spatial distribution of water bodies modeled from our approach agreed well with the water locations visually identified from the aerial photography records; and iii) the R² between our modeled water bodies (including both large and small wetlands) and those from aerial photography records could be up to 0.83 with a mean average error of 0.64 km² within the study area where the modeled wetland water areas ranged from about 2 to 14 km². These results indicate that our approach holds great potential to simulate major changes in wetland water surface for ecosystem service; however, our products could capture neither the short-term water change caused by intensive rainstorm events nor the wetland change caused by human activities.     

An adaptive ensemble classifier for mining concept drifting data streams

It is challenging to use traditional data mining techniques to deal with real-time data stream classifications. Existing mining classifiers need to be updated frequently to adapt to the changes in data streams. To address this issue, in this paper we propose an adaptive ensemble approach for classification and novel class detection in concept drifting data streams. The proposed approach uses traditional mining classifiers and updates the ensemble model automatically so that it represents the most recent concepts in data streams. For novel class detection we consider the idea that data points belonging to the same class should be closer to each other and should be far apart from the data points belonging to other classes. If a data point is well separated from the existing data clusters, it is identified as a novel class instance. We tested the performance of this proposed stream classification model against that of existing mining algorithms using real benchmark datasets from UCI (University of California, Irvine) machine learning repository. The experimental results prove that our approach shows great flexibility and robustness in novel class detection in concept drifting and outperforms traditional classification models in challenging real-life data stream applications.     

Hexagonal boron nitride epitaxial layers as neutron detector materials

Micro-strip metal-semiconductor-metal detectors for thermal neutron sensing were fabricated from hexagonal boron nitride (hBN) epilayers synthesized by metal organic chemical vapor deposition. Experimental measurements indicated that the thermal neutron absorption coefficient and length of natural hBN epilayers are about 0.00361 μm⁻¹ and 277 μm, respectively. A continuous irradiation with a thermal neutron beam generated an appreciable current response in hBN detectors, corresponding to an effective conversion efficiency approaching ∼80% for absorbed neutrons. Our results indicate that hBN semiconductors would enable the development of essentially ideal solid-state thermal neutron detectors in which both neutron capture and carrier collection are accomplished in the same hBN semiconductor. These solid-state detectors have the potential to replace ³He gas detectors, which faces the very serious issue of ³He gas shortage.     

A case study of scheduling storage tanks using a hybrid geneticalgorithm

This paper proposes the application of a hybrid genetic algorithm (GA) for scheduling storage tanks. The proposed approach integrates GAs and heuristic rule-based techniques, decomposing the complex mixed-integer optimization problem into integer and real-number subproblems. The GA string considers the integer problem and the heuristic approach solves the real-number problems within the GA framework. The algorithm is demonstrated for three test scenarios of a water treatment facility at a port and has been found to be robust and to give a significantly better schedule than those generated using a random search and a heuristic-based approach