Yttria stabilized zirconia formed by micro ceramic injection molding: Rheological properties and debinding effects on the sintered part

Micro Ceramic Injection Molding (μCIM) is a near net-shape process to produce smaller and intricate parts at a competitive cost. The application of nano-sized ceramic powder in μCIM has the advantages of fine grain size growth and good surface finish. However, the nano size effect causes agglomeration and low powder loadings, which result in defects during the μCIM process and in the sintered components. This study extensively investigated the debinding and sintering of yttria-stabilized zirconia (YSZ), as well as its rheological properties, using polypropylene (PP) as the primary binder and palm stearin as the secondary binder. 50 nm Yttria stabilized zirconia (YSZ) powders were mixed with palm stearin and PP at a powder loading of 37–43 vol%. The results of rheological studies showed that the feedstock had a dilatant flow characteristic and a viscosity of around 10–40 Pa s. Feedstock with 38 vol% powder loading had the lowest activation energy of 9.48 kJ/mol. The green part of the injected feedstock had flexural strength ranging from 13 to16 MPa, within which the feedstock with 43 vol% powder loading had the highest green density. Solvent debinding was carried out at three temperatures (50, 60, and 70 °C) using heptane. A large porous region was clearly identified at 70 °C compared with 50 °C. A debinding split furnace with argon gas was used to remove PP at 450 °C for 4 h. The debound samples did not shrink when 94%–98% of the binder system was removed. All debound samples sintered at 1350 °C and 41 vol% had the highest mechanical properties with hardness of 900 HV and a flexural strength of 400 MPa.     

Urease-Based Biocatalytic Platforms―A Modern View of a Classic Enzyme with Applied Perspectives

Catalysis Letters - The biotechnology industry is currently seeking increased or improved enzyme efficiency and the emergence of new methods to maximize their shelf-life. Enzyme immobilization on...     

Chemical compositions and fatty acid profiles of three freshwater fish species

This study investigated the chemical composition and fatty acid profiles of Cyprinus(C) carpio, Labeo(L) rohita and Oreochromis(O) mossambicus from the Indus River, Pakistan. Significant differences were observed for most chemical components and fatty acids (P < 0.01) in the examined fish species. O. mossambicus,C. carpio and L. rohita were high in saturated, mono-unsaturated and poly-unsaturated fatty acids, respectively. Palmitic acid was the most abundant fatty acid in all species ranging from 32% to 46%. Although these fish contained reasonable amounts of essential PUFA such as docosahexaenoic, eicosapentaenoic and arachidonic acids, L. rohita contained the highest amounts of PUFA and protein. These fish contained appreciable levels of Omega-6 PUFA suggesting that these fish especially L. rohita could be used as a source of healthy diet for humans. These findings may benefit the fishing industry, nutritionists and researchers who are striving to improve the nutritive value, processing and marketing of selected fish species.     

Barrier properties and abrasion resistance of biopolymer‐based coatings on biodegradable poly(lactic acid) films

Coated polylactic acid (PLA) films consisting of crosslinked‐chitosan/beeswax layer were prepared to improve barrier properties and abrasion resistance of the base substrate. The effect of crosslinking the chitosan layer on durability and barrier properties of the coatings was investigated. Crosslinked samples exhibited lower degree of swelling compared to uncrosslinked samples and 50% reduction in water vapor transmission rate (WVTR) compared to neat PLA films. The beeswax coating decreased the WVTR of chitosan‐coated PLA films significantly (by 100%). However, it had a marginal effect on the oxygen transmission rate. Water vapor transmission was less affected by abrasion than oxygen transmission for both uncrosslinked and crosslinked samples. The WVTR of crosslinked samples were retained even after being subjected to abrasion, whereas WVTR of uncrosslinked samples dropped by 50%. Results obtained using the Taber test method also show that the weight loss of crosslinked coatings are about 75% less than that of uncrosslinked samples and can withstand a greater number of cycles before rupture. These translucent‐coated films retained good barrier and mechanical properties along with providing improved abrasion resistance after crosslinking. This approach provides exciting new possibilities for expanding the use of biodegradable polymers in packaging applications. POLYM. ENG. SCI., 59:1874–1881, 2019. © 2019 Society of Plastics Engineers     

Biodegradation of chlorpyrifos and 3, 5, 6‐trichloro‐2‐pyridinol by a novel rhizobial strain Mesorhizobium sp. HN3

A chlorpyrifos (CP) and 3,5,6‐trichloro‐2‐pyridinol (TCP) degrading bacterial strain, Mesorhizobium sp. HN3, was isolated and characterized. Mesorhizobium sp. HN3 degraded CP efficiently up to 400 mg/L initial concentration at wide range of temperatures (30–40°C) and pH (6.0–8.0). However, optimal degradation of CP was achieved at 37°C and neutral pH (7.0) at an initial inoculum density 2 × 10⁷ colony forming unit/mL of culture medium. Kinetic parameters for CP degradation by Mesorhizobium sp. HN3 were estimated at different initial concentrations. Cultures exhibited significant variation (P ≤ 0.05) in the specific growth rate (μ), cell mass formation rate (Q_X) and the substrate uptake rate (Q_S) during degradation of CP. The values of kinetic parameters increased up to 100 mg/L CP and decreased at higher concentration. Investigation of degradation metabolites indicated that CP is converted to diethylthiophosphate and TCP that leads to the formation of 3,5,6‐trichloro‐2‐methoxypyridine.     

Therapeutic Approach of Flavonoid in Ameliorating Diabetic Cardiomyopathy by Targeting Mitochondrial-Induced Oxidative Stress

Diabetes cardiomyopathy is one of the key factors of mortality among diabetic patients around the globe. One of the prior contributors to the progression of diabetic cardiomyopathy is cardiac mitochondrial dysfunction. The cardiac mitochondrial dysfunction can induce oxidative stress in cardiomyocytes and was found to be the cause of majority of the heart morphological and dynamical changes in diabetic cardiomyopathy. To slow down the occurrence of diabetic cardiomyopathy, it is crucial to discover therapeutic agents that target mitochondrial-induced oxidative stress. Flavonoid is a plentiful phytochemical in plants that shows a wide range of biological actions against human diseases. Flavonoids have been extensively documented for their ability to protect the heart from diabetic cardiomyopathy. Flavonoids’ ability to alleviate diabetic cardiomyopathy is primarily attributed to their antioxidant properties. In this review, we present the mechanisms involved in flavonoid therapies in ameliorating mitochondrial-induced oxidative stress in diabetic cardiomyopathy.     

Potential use of nanofiltration like-forward osmosis membranes for copper ion removal

The discharge of industrial effluent containing heavy metal ions would cause water pollution if such effluent is not properly treated. In this work, the performance of emerging nanofiltration(NF) like-forward osmosis(FO)membrane was evaluated for its efficiency to remove copper ion from water. Conventionally, copper ion is removed from aqueous solution via adsorption and/or ion-exchange method. The engineered osmosis method as proposed in this work considered four commercial NF membranes(i.e., NF90, DK, NDX and PFO) where their separation performances were accessed using synthetic water sample containing 100 mg·L~(-1) copper ion under FO and pressure retarded osmosis(PRO) orientation. The findings indicated that all membranes could achieve almost complete removal of copper regardless of membrane orientation without applying external driving force.The high removal rates were in good agreement with the outcomes of the membranes tested under pressuredriven mode at 1 MPa. The use of appropriate salts as draw solutes enabled the NF membranes to be employed in engineered osmosis process, achieving a relatively low reverse solute flux. The findings showed that the best performing membrane is PFO membrane in which it achieved N 99.4% copper rejection with very minimum reverse solute flux of 1 g·m~(-2)·h~(-1).     

Ganglioside GD2 Enhances the Malignant Phenotypes of Melanoma Cells by Cooperating with Integrins

Gangliosides have been considered to modulate cell signals in the microdomain of the cell membrane, lipid/rafts, or glycolipid-enriched microdomain/rafts (GEM/rafts). In particular, cancer-associated gangliosides were reported to enhance the malignant properties of cancer cells. In fact, GD2-positive (GD2+) cells showed increased proliferation, invasion, and adhesion, compared with GD2-negative (GD2−) cells. However, the precise mechanisms by which gangliosides regulate cell signaling in GEM/rafts are not well understood. In order to analyze the roles of ganglioside GD2 in the malignant properties of melanoma cells, we searched for GD2-associating molecules on the cell membrane using the enzyme-mediated activation of radical sources combined with mass spectrometry, and integrin β1 was identified as a representative GD2-associating molecule. Then, we showed the physical association of GD2 and integrin β1 by immunoprecipitation/immunoblotting. Close localization was also shown by immuno-cytostaining and the proximity ligation assay. During cell adhesion, GD2+ cells showed multiple phospho-tyrosine bands, i.e., the epithelial growth factor receptor and focal adhesion kinase. The knockdown of integrin β1 revealed that the increased malignant phenotypes in GD2+ cells were clearly cancelled. Furthermore, the phosphor-tyrosine bands detected during the adhesion of GD2+ cells almost completely disappeared after the knockdown of integrin β1. Finally, immunoblotting to examine the intracellular distribution of integrins during cell adhesion revealed that large amounts of integrin β1 were localized in GEM/raft fractions in GD2+ cells before and just after cell adhesion, with the majority being localized in the non-raft fractions in GD2− cells. All these results suggest that GD2 and integrin β1 cooperate in GEM/rafts, leading to enhanced malignant phenotypes of melanomas.     

Error Detection and Pattern Prediction Through Phase II Process Monitoring

The continuous monitoring of the machine is beneficial in improving its process reliability through reflected power function distribution. It is substantial for identifying and removing errors at the early stages of production that ultimately benefit the firms in cost-saving and quality improvement. The current study introduces control charts that help the manufacturing concerns to keep the production process in control. It presents an exponentially weighted moving average and extended exponentially weighted moving average and then compared their performance. The percentiles estimator and the modified maximum likelihood estimator are used to constructing the control charts. The findings suggest that an extended exponentially weighted moving average control chart based on the percentiles estimator performs better than exponentially weighted moving average control charts based on the percentiles estimator and modified maximum likelihood estimator. Further, these results will help the firms in the early detection of errors that enhance the process reliability of the telecommunications and financing industry.