Gelatin‐carbohydrate phase‐separated hydrogels as bioactive carriers in vaginal delivery: Preparation and physical characterizations

The current study focuses on the alteration of properties of the gelatin hydrogels using polysaccharides (e.g., maltodextrin, dextran, and sodium carboxymethyl cellulose) for probable use in vaginal delivery of antimicrobials. The hydrogels were prepared by varying the proportions of gelatin and polysaccharides and were characterized by microscopy, mechanical testing, and impedance spectroscopy. Metronidazole (MZ), drug of choice for the treatment of bacterial vaginosis, was incorporated within the hydrogels. In vitro release studies of MZ from the hydrogels was studied in‐depth using modified Franz's diffusion cell. Antimicrobial efficiency of the MZ‐loaded hydrogels was tested against E. coli and B. subtilis. The results suggested that the incorporation of polysaccharides resulted in the phase‐separated hydrogels. The properties of the hydrogels was found be suitable for vaginal delivery. The drug release and antimicrobial efficiency from the hydrogels suggested that the developed hydrogels may be used for the delivery of antimicrobials in the vaginal lumen. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40445.     

Palm oil‐based organogels and microemulsions for delivery of antimicrobial drugs

This study has been designed to develop palm oil (PO) based organogels using span 80/tween 80 mixture (OG) as a gelator system by fluid‐filled structure mechanism. The results suggested formation of organogels, emulsions, and microemulsions as the proportions of PO, OG and water were varied. The emulsions were found to be thermodynamically unstable as compared to the organogels and the microemulsions. Accelerated thermal stability test suggested that all the microemulsions and the organogels of only eight compositions were stable. The organogels showed viscoelastic property while the microemulsions showed viscous flow behavior. Both the organogels and the microemulsions were found to be highly hemocompatible and nonirritant. The antimicrobial efficiency of the ciprofloxacin HCl‐loaded formulations showed equivalent efficiency as compared to marketed formulations. The rates of drug release from the organogels were found to be relatively slower as compared to the microemulsions. The preliminary studies suggested that the developed organogel and microemulsion‐based formulations may be tried for topical delivery of antimicrobials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39979.     

Recovery of copper from a surface altered chalcopyrite contained ball mill spillage through bio-hydrometallurgical route

Bioleaching studies for chalcopyrite contained ball mill spillages are very scarce in the literature. We developed a process flow sheet for the recovery of copper metal from surface activated (600 °C, 15 min) ball mill spillage through bio-hydrometallurgical processing route. Bioleaching of the activated sample using a mixed meso-acidophilic bacterial consortium predominantly A. ferrooxidans strains was found to be effective at a lixiviant flow rate of 1.5 L/h, enabling a maximum 72.36% copper recovery in 20 days. Mineralogical as well as morphological changes over the sample surface were seen to trigger the bioleaching efficiency of meso-acidophiles, thereby contributing towards an enhanced copper recovery from the ball mill spillage. The bio-leach liquor containing 1.84 g/L Cu was purified through solvent extraction using LIX 84I in kerosene prior to the recovery of copper metal by electrowinning. Purity of the copper produced through this process was 99.99%.     

Multicomponent bulk metal nitride (Nb1/3Ta1/3Ti1/3)N1−δ synthesis via reaction flash sintering and characterizations

In this research, near fully dense single phase bulk multicomponent transition metal nitride (Nb_1/3Ta_1/3Ti_1/3)N_1−δ has been successfully synthesized from mixed commercial powders of NbN, TaN and TiN via reaction flash sintering technique. This was performed with an applied pressure of ~ 35 MPa at 25°C under a constant DC electric field (~24-32 V/cm). The flash event, which is the abrupt increase in current (up to ~ 25.2 A/mm²) and temperature, occurred without preheating. The threshold power dissipation on the sample right before the flash is ~ 0.7 W/mm³. The formation of single phase (Nb_1/3Ta_1/3Ti_1/3)N_1−δ random solid solution and its compositional uniformity were confirmed by XRD and EDS, respectively. The effects of ball milling duration and limiting current density on phase formation were studied. Simulation based on Joule heating provides an estimate of the ultimate sample temperature of ~ 1850°C. Vickers hardness of the obtained (Nb_1/3Ta_1/3Ti_1/3)N_1−δ is 17.6 ± 0.6 GPa, which is comparable to similarly flash sintered ingredient binary nitrides of TaN and NbN. TGA in air shows that the oxidation resistance of (Nb_1/3Ta_1/3Ti_1/3)N_1−δ is better than that of TaN and NbN but inferior to TiN. The study demonstrates that reaction flash sintering can be a highly efficient technique for synthesizing bulk multicomponent ceramics for both material fundamental investigations and application development.     

Guayule natural rubber composites: impact of fillers on their cure characteristics,dynamic and mechanical behavior

Guayule natural rubber (GNR) is an alternative resource of Hevea natural rubber (HNR) with 99.9% cis content in its 1,4-polyisoprene chemical backbone. In this study, compounds were formulated independently with four different reinforcing fillers such as carbon black (HAF), precipitated silica (VN3), fume silica (FUM) and nanofly ash (NFA) for the advancement of GNR based products. The cure characteristic, dynamic-mechanical performance and mechanical properties of GNR composite were studied with the reinforcing effect of different fillers on GNR. The cure characteristic results demonstrated that HAF and FUM silica filled compounds had more processing safety than VN3 and NFA filled compounds. Viscoelastic parameters of the vulcanizates were studied by dynamic mechanical analysis to estimate the glass transition characteristics and dynamic behavior. The higher storage modulus of FUM silica vulcanizate was an indication of superior filler reinforcing nature and improved rolling resistance than other filled systems. Additionally, HRTEM analysis also proved the better filler dispersion ability of FUM silica in GNR matrix. The mechanical properties were studied with a variation of each filler loading of 8, 16, and 32 phr in GNR vulcanizates. The tensile strength of each filled system increased with an increase of filler content from 8 to 32 phr. In comparison, FUM silica GNR vulcanizates exhibited better mechanical properties, therefore, it was considered as a better structure-performance composite than those of HAF, VN3 and NFA filled composites.

     

Genetic Deficiency and Pharmacological Stabilization of Mast Cells Ameliorate Pressure Overload-Induced Maladaptive Right Ventricular Remodeling in Mice

Although the response of the right ventricle (RV) to the increased afterload is an important determinant of the patient outcome, very little is known about the underlying mechanisms. Mast cells have been implicated in the pathogenesis of left ventricular maladaptive remodeling and failure. However, the role of mast cells in RV remodeling remains unexplored. We subjected mast cell-deficient WBB6F1-KitW/W-v (Kit^W/Kit^W-v) mice and their mast cell-sufficient littermate controls (MC^+/+) to pulmonary artery banding (PAB). PAB led to RV dilatation, extensive myocardial fibrosis, and RV dysfunction in MC^+/+ mice. In PAB Kit^W/Kit^W-v mice, RV remodeling was characterized by minimal RV chamber dilatation and preserved RV function. We further administered to C57Bl/6J mice either placebo or cromolyn treatment starting from day 1 or 7 days after PAB surgery to test whether mast cells stabilizing drugs can prevent or reverse maladaptive RV remodeling. Both preventive and therapeutic cromolyn applications significantly attenuated RV dilatation and improved RV function. Our study establishes a previously undescribed role of mast cells in pressure overload-induced adverse RV remodeling. Mast cells may thus represent an interesting target for the development of a new therapeutic approach directed specifically at the heart.     

Spatial prediction of landslide susceptibility using data mining-based kernel logistic regression,naive Bayes and RBFNetwork models for the Long County area (China)

The main goal of this study is to assess and compare three advanced machine learning techniques, namely, kernel logistic regression (KLR), naïve Bayes (NB), and radial basis function network (RBFNetwork) models for landslide susceptibility modeling in Long County, China. First, a total of 171 landslide locations were identified within the study area using historical reports, aerial photographs, and extensive field surveys. All the landslides were randomly separated into two parts with a ratio of 70/30 for training and validation purposes. Second, 12 landslide conditioning factors were prepared for landslide susceptibility modeling, including slope aspect, slope angle, plan curvature, profile curvature, elevation, distance to faults, distance to rivers, distance to roads, lithology, NDVI (normalized difference vegetation index), land use, and rainfall. Third, the correlations between the conditioning factors and the occurrence of landslides were analyzed using normalized frequency ratios. A multicollinearity analysis of the landslide conditioning factors was carried out using tolerances and variance inflation factor (VIF) methods. Feature selection was performed using the chi-squared statistic with a 10-fold cross-validation technique to assess the predictive capabilities of the landslide conditioning factors. Then, the landslide conditioning factors with null predictive ability were excluded in order to optimize the landslide models. Finally, the trained KLR, NB, and RBFNetwork models were used to construct landslide susceptibility maps. The receiver operating characteristics (ROC) curve, the area under the curve (AUC), and several statistical measures, such as accuracy (ACC), F-measure, mean absolute error (MAE), and root mean squared error (RMSE), were used for the assessment, validation, and comparison of the resulting models in order to choose the best model in this study. The validation results show that all three models exhibit reasonably good performance, and the KLR model exhibits the most stable and best performance. The KLR model, which has a success rate of 0.847 and a prediction rate of 0.749, is a promising technique for landslide susceptibility mapping. Given the outcomes of the study, all three models could be used efficiently for landslide susceptibility analysis.

     

Electrical Conduction in Nano-Structured La0.9Sr0.1Al0.85Co0.05Mg0.1O3 Perovskite Oxide

Nanocrystalline La_0.9Sr_0.1Al_0.85Co_0.05Mg_0.1O₃ oxide powder was synthesized by a citrate–nitrate auto-ignition process and characterized by thermal analysis, X-ray diffraction, and impedance spectroscopy measurements. Nanocrystalline (50–100 nm) powder with perovskite structure could be produced at 900°C by this process. The powder could be sintered to a density more than 96% of the theoretical density at 1550°C. Impedance measurements on the sintered samples unequivocally established the potential of this process in developing nanostructured lanthanum aluminate-based oxides. The sintered La_0.9Sr_0.1Al_0.85Co_0.05Mg_0.1O₃ sample exhibited a conductivity of 2.40 × 10⁻² S/cm in air at 1000°C compared with 4.9 × 10⁻³ S/cm exhibited by La_0.9Sr_0.1Al_0.85Mg_0.15O₃.     

Quantitative risk assessment of listeriosis due to consumption of raw milk

The objectives of this study were to estimate the risk of illness for raw milk consumers due to Listeria monocytogenes in raw milk sold by permitted dealers, and the risk for people on farms who consume raw milk. Three scenarios were evaluated for raw milk sold by dealers: raw milk purchased directly from bulk tanks, from on-farm stores, and from retail. To assess the effect of mandatory testing of raw milk by regulatory agencies, the number of listeriosis cases per year was compared where no raw milk testing was done, only a screening test to issue a permit was conducted, and routine testing was conducted and milk was recalled if it was L. monocytogenes positive. The median number of listeriosis cases associated with consumption of raw milk from bulk tanks, farm stores, and retail for an intermediate-age population was 6.6 × 10(-7), 3.8 × 10(-5), and 5.1 × 10(-5) cases per year, respective ly. In populations with high susceptibility, the estimated median number of cases per year was 2.7 × 10(-7) (perinatal, i.e., pregnant women and their fetuses or newborns) and 1.4 × 10(-6) (elderly) for milk purchased from bulk tanks, 1.5 × 10(-5 ) (perinatal) and 7.8 × 10(-5) (elderly) for milk from farm stores, and 2.1 × 10(-5) (perinatal) and 1.0 × 10(-4) (elderly) for milk from retail. For raw milk consumed on farms, the median number of listeriosis cases was 1.4 × 10(-7) cases per year. A greater risk of listeriosis was associated with consumption of raw milk obtained from retail and farm stores as compared with milk obtained from bulk tanks. This was likely due to additional time-temperature combination steps in the retail and farm store models, which increased the chances for growth of L. monocytogenes in raw milk. A close relationship between prevalence of L. monocytogenes in raw milk and the values of disease incidence was observed. Hence, a reduction in the number of cases per year in all populations was observed when a raw milk-testing program was in place, especially when routine testing and recalling of milk was conducted.     

Microwave Preparation of SiO2-B2O3-Na2O-K2O-CaO-Fe2O3-TiO2 Glass System

This study reports preparation of glass composition （54.50 wt.%） SiO2, （10.80 wt.%） B2O3, （14.20 wt.%） Na2O, （1.20 wt.%） K2O, （6.00 wt.%） CaO, （4.00 wt.%） Fe2O3 and （9.30 wt.%） TiO2 by melt quenching method using direct microwave heating and conventional resistive heating. Study of dielectric loss factor of the glass as function of temperature illustrated increasing loss factor above 370 ℃, 550 ℃, 650 ℃ and 900 ℃, indicating enhanced microwave absorption by the glass at above these temperatures. Chemical analysis results of both the glasses depicted more volatilization loss of volatile ingredients in conventional heating. The study of chemical durability was performed from leachate analysis describing less leaching of Na2O, K2O and other constituents from glass melted in microwave furnace. Glass transition temperatures （Tg） were found to be 576.3 ℃ and 569.5 ℃ for glass melted in conventional and microwave heating route, respectively. Laboratory experiment of glass melting utilizing microwave energy as an alternate heating source demonstrated 70%-75% electrical power saving.