Polylactic acid/carbon fiber composites: Effects of functionalized elastomers on mechanical properties,thermal behavior,surface compatibility,and electrical characteristics

In this study, the maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer (SEBS-g-MA) is used as the compatilizer for polylactic acid (PLA)/carbon fiber (CF) composites. The effects of SEBS-g-MA on the mechanical properties, thermal behavior, interfacial compatibility, and electrical characteristics of composites are then evaluated. The mechanical property tests indicate that when the amount of compatilizer increases, the tensile properties and flexural property of the composites decrease while their impact strength increases. The SEM results show that the compatilizer can decrease the interstices between PLA and CF, and thereby augments their interfacial compatibility. The differential scanning calorimetry (DSC) results confirm that the compatilizer results in a greater crystallization temperature and a greater crystallinity of the composites. The electrical characteristic results indicate that neither PLA nor SEBS-g-MA is not interfered with the conductive network that is constructed by CF, which is exemplified by an average electromagnetic shielding effect of above ?30 dB. This study confirms that SEBS-g-MA can improve interfacial compatibility and toughness, as well as attain good electrical characteristics of PLA/CF composites.     

Influence of Particle Size on the Twin-Screw Extrusion of Corn Meal

Effects of particle size (50–1,622 μm), screw speed (200–400 rpm), and feed moisture content (19–22%) on twin-screw extrusion of corn meal were investigated using a full-factorial design. Torque, specific mechanical energy, and product temperature generally showed no change within the commonly used particle-size range (100–1,000 μm), but each value dropped significantly as the particle size increased >1,000 μm. Die pressure was influenced by the three-way interaction of particle size, screw speed, and feed moisture content. The highest moisture level (22%), largest particle size (1,622 μm), and two lowest screw speeds (200 and 300 rpm) were the only conditions where the starch was <97.5% of transformation (gelatinization). Consequently, these two conditions also showed the least expansion and hardest product.     

Black soybean seed coat containing diet enhancing the growth performance of juvenile hybrid tilapia Orechromis nitoticus × O. aureus

Black soybeans contain high amount of antioxidant, such as phenolic compounds and anthocyanins, in their seed coat. This study aimed to investigate the beneficial effect of black soybean seed coat (BSSC) on the growth of juvenile hybrid tilapia. There were four experimental diets: casein based diet (the control diet), casein based diet with 20% BSSC, and soybean and black soybean based diets. The results showed that after 8 weeks feeding period, BSSC meal increased 16% of the weight gain in the fish. When soybean and black soybean were used to replace casein as the main protein source, the diets resulted in poor growth performance and feed utilization and induced oxidative stress in the fish. It was suggested that oxidative stress induced by soybean based diets was due to the anti‐nutritional factors presented in the soybean and black soybean.     

Pharmacokinetic–pharmacodynamic modelling for the determination of optimal dosing regimen of florfenicol in Nile tilapia (Oreochromis niloticus) at different water temperatures and antimicrobial susceptibility levels

Optimized dosing regimen is key to the effective use of antibacterials and to minimizing drug‐related side effects. The current study established a pharmacokinetic–pharmacodynamic (PK‐PD) model for the determination of optimal antibacterial dosing regimen in fish taken into consideration the temperature‐dependent PK and the pathogen‐dependent antimicrobial susceptibility, using florfenicol (FF) in Nile tilapia as an example. The calculated optimal dosages significantly varied by temperature and target MIC levels, ranging from 2.23 (MIC 1 µg/ml at 24°C) to 34.88 mg kg^?1 day^?1 (MIC 4 µg/ml at 32°C). The appropriateness of the calculated dosages was successfully verified by the in vivo studies. After 5 days of oral administration of the calculated optimal dosage at 24°C, the predicted plasma drug values were in line with the mean observed C_min(ss) while at 28 and 32°C underestimation of the C_min(ss) in a dose‐dependent manner was observed and likely due to the occurrence of non‐linear PK at high dosages. The averaged serum protein binding of FF was 19.1%. Our results demonstrated the appropriateness and clinical applicability of the developed PK‐PD approach for the determination of optimal dosing regimens at given temperatures and MICs. Saturation metabolism and PK non‐linearity of FF in tilapia warrant further study.     

Proteomic profiling of the coagulation of milk proteins induced by chymosin

Chymosin-induced coagulation of individual milk proteins during incubation at 30 °C was investigated using a proteomic approach. The addition of chymosin (0.006 units/mL) caused the milk proteins to coagulate after a 3 h incubation period. Approximately 88% of the milk proteins were coagulated into the milk pellet fraction, and the protein concentration of the milk supernatant fraction (MSF) decreased from 29.88 ± 0.12 to 3.74 ± 0.13 mg/mL. SDS-PAGE analysis showed that α(S)-, β- and κ-caseins in the MSF were almost depleted and that the total intensity of the protein bands corresponding to α(S)-caseins (α(S1) and α(S2)), β-casein, and κ-casein decreased from 1088.0, 901.5, and 617.0 area units to 6.9, 6.1, and 5.2 area units, respectively. Two-dimensional electrophoresis analysis indicated that α(S1)-, α(S2)-, β-, and κ-casein and a fraction of the β-lactoglobulin and serum albumin were found in the MSF following incubation with chymosin.     

Antioxidative activity and active components of longan (Dimocarpus longan Lour.) flower extracts

Three different solvent extracts (methanol, ethyl acetate, and n-hexane) of longan ( Dimocarpus longan Lour.) flowers were assayed with three different antioxidant capacity methods, namely, the DPPH free radical scavenging effect, the oxygen radical absorbance capacity (ORAC) assay, and the inhibition of Cu(2+)-induced oxidation of human low-density lipoprotein (LDL). It was revealed that the methanol extract has the best antioxidative activity, followed by ethyl acetate and n-hexane extracts. The methanol extract was separated by liquid-liquid partition into n-hexane, ethyl acetate, n-butanol, and water fractions. The ethyl acetate fraction was found to have the highest activity of delaying LDL oxidation. After silica gel column chromatography, the fraction having a superior activity was identified as containing two major compounds, (-)-epicatechin and proanthocyanidin A2.     

Disposition of fenbendazole in the goat

The disposition of fenbendazole was studied in goats after oral or IV administration. Plasma concentration vs time profiles were determined for fenbendazole and all of its metabolites. The total excretion of the drug and its metabolites in urine and feces was also measured for 6 days. A biliary cannula was inserted in 1 goat to study the excretion of fenbendazole and its metabolites into the bile. Fenbendazole was converted to its sulfoxide (oxfendazole), and the sulfone, primary amine, and p-hydroxylated metabolites. The active metabolite, oxfendazole, appeared in plasma, but only trace amounts were found in feces or urine. The major excretory metabolite was p-hydroxyfenbendazole.     

Cover Image,Volume 76, Issue 4

The cover image is based on the Research Article A rapid insect species identification system using mini‐barcode pyrosequencing by Chia‐Hung Hsieh et al., https://doi.org/10.1002/ps.5674 .

     

Electron microscopy analysis of carboxymethylcellulase in rhizobia

Here we analyzed carboxymethylcellulase (CMCase; EC 3, 2, 1, 4), one of the key enzymes in the early symbiotic process, in Rhizobium. Specific immunogold labeling of electron microscopy was confirmed in Sinorhizobium fredii BCRC15769, ATCC35423, Sinorhizobium meliloti ATCC9930, and barely detected in Bradyrhizobium japonicum BCRC13528, ATCC10324 and Rhizobium rhizogenes ATCC11325. Non-specific labeling was detected in Rhizobium leguminosarum bv. viceae ATCC10004, Rhizobium leguminosarum bv. trifolii ATCC10328, and Mesorhizobium loti ATCC33669. Treatment of S. fredii BCRC15769 in the early log phase with the flavonoid genistein caused relocalization of CMCase. Together our data suggests a role for CMCase in early symbiosis.