Aligning Crystal Orientation of Poly-Crystalline Bi-Te With a High Magnetic Field

We investigated the effect of aligning crystal orientation in the microstructures containing sub micro-sized grains on the thermoelectric properties for polycrystalline Bi-Te materials.Bi-Te powder,prepared through the conventional pulverization process,was sufficiently dispersed in an appropriate solvent,and then was formed into c-axis aligned green bodies under a designated high magnetic field.The green bodies were sintered with spark-plasma-sintering machine.The degree of crystal alignment of sintered bodies was examined with the electron-back-scatter-diffraction SEM and the X-ray diffraction patterns.It was observed that for both p and n type thermoelectric Bi-Te materials,aligning crystal orientation properly made electrical resistivity decreased with keeping Seebeck coefficient and thermal conductivity remained unchanged.As a typical result,the aligned Bi-Te material with the magnetic field of 10 tesla showed 30%enhancement of the thermoelectric performance.     

INHIBITION STUDIES ON BURDOCK POLYPHENYL OXIDASE (PPO) ACTIVITY

The inhibitory effect of 4-hexylresorcinol (HR), ascorbic acid (AA), citric acid (CA), and bisulfites on polyphenol oxidase (PPO) of burdock roots was studied. HR was an effective inhibitor at low concentrations used in this study for crude PPO from root slices. A binary mixture of HR and AA at 1.0% concentration for 5 min achieved more than 90% inhibition of crude PPO. AA also showed high antibrowning activity for the purified PPO comparable to that of bisulfites, whereas its activity was much lower than that of HR in the crude extract. The inhibitory effect of the combined use of inhibitors was overall in the decreasing order of HR+AA, HR+CA and AA+CA, irrespective of the crude PPO or the purified PPO from burdock slices.     

Gram Negative Bacteria Inhibition by Lactic Acid Culture and Food Preservatives on Catfish Fillets during Refrigerated Storage

Treating catfish fillets with sodium acetate (SA) and/or potassium sorbate (PS), with or without lactic culture (Lactococcus lactic spp. cremoris ATCC 19257 grown in 20% milk solids) was studied at 4°C. Gram negative bacterial (CVT) counts on crystal violet tetrazolium chloride agar, pH, and sensory evaluation of fillets were assessed over time. Treatment with the combination of 0.50% SA, 0.25% PS with 2.50% lactic acid culture (LC) and, also, 0.50 to 1.00% SA alone completely inhibited growth for 6 days at 4°C. After 12 days, counts with this treatment and the 1.00% SA increased ～1.3 and 1.2 log cycles, respectively. The antimicrobial effects did not appear to be due to pH values. The combination of 0.50% SA and 0.25% PS with 2.50% LC, or 1.00% SA, alone, improved catfish odor and appearance during 13 days storage.     

Immunoglobulin Separation from Egg Yolk: A Serial Filtration System

A serial filtration system was developed for separating immunoglobulin from egg yolk (IgY). Egg yolk was diluted 10 times with water, adjusted to pH 5.0, frozen, then thawed. The diluted yolk was diafiltered through a hard filter paper at 4-6°C to produce a clear water-soluble fraction (WSF). The WSF was then delipidated by filtering through a hydrophobic membrane filter. Ultrafiltration of delipidated WSF at pH 9.0, at 4-6°C, in the presence of 1.5M NaCl resulted in electrophoretically pure (>90%) IgY with a recovery of about 92%. Advantages of this method are the use of only a few mild chemicals and the potential of developing a continuous process.     

OVER-EXPRESSION OF PROLINE-LINKED ANTIOXIDANT PATHWAY AND MODULATION OF PHENOLIC METABOLITES IN LONG LIFE SPAN CLONAL LINE OF ORIGANUM VULGARE IN RESPONSE TO ULTRAVIOLET RADIATION

Tissue culture-generated shoot-based clonal lines of oregano that have a short and long life span during in vitro culture were investigated to determine the role of proline-linked pentose phosphate pathway in modulating phenolic response following ultraviolet (UV) exposure. This novel reductant cycling pathway for energy and oxidative pentose phosphate pathway (PPP) is more efficient in long life span O-17 clonal line in response to UV and this supported antioxidant response. UV treatment stimulated rosmarinic acid and associated antioxidant enzyme response in O-17 clonal line compared with short life span O-3 clonal line. Additionally, O-17 clonal line had higher glucose-6-phosphate dehydrogenase and guaicol peroxidase activity in response to UV exposure compared with O-3 clonal line, indicating stimulation of anabolic pathway supporting PPP during UV treatment. The stimulation of proline dehydrogenase (PDH) activity in O-17 clonal line in response to UV indicated a switch to PDH-linked energy pathway via proline oxidation.

PRACTICAL APPLICATIONS

This oregano clonal model of ultraviolet (UV)-induced oxidative stress management has implications for designing dietary phytochemicals to manage oxidation-linked disease in humans. Further, the correlation between UV-linked inducibility of phenolic-linked antioxidant enzyme response through proline-linked pentose phosphate pathway and life span of in vitro shoot cultures of specific oregano clonal lines can be a good model for aging studies. The metabolic response link to aging and protective phytochemicals can be investigated in oregano tissue cultures, and phenolic extracts from various responding clonal lines could be explored in other eukaryotic aging models.     

平贝母多糖对D-半乳糖诱导衰老模型小鼠的抗氧化作用

为了探讨平贝母多糖对D-半乳糖诱导衰老模型小鼠的体内抗氧化作用,采用颈背皮下注射D-半乳糖(500mg/(kg ·d))建立亚急性衰老小鼠模型,通过对各组小鼠一般体征、脏器指数、血清或肝组织抗氧化酶活性及脑组织单胺氧化酶(MAO)活力的比较分析,全面评价平贝母多糖FUP-1的抗氧化衰老作用。结果表明：与模型组相比平贝母多糖FUP-1能显著降低D-半乳糖诱导衰老小鼠肝脏组织中丙二醛(MDA)含量(P＜0.05),提高肝组织中总抗氧化能力(T-AOC)、显著提高肝组织中谷胱甘肽过氧化物酶(GSH-Px)活性和血清超氧化物歧化酶(SOD)活性(P＜0.05),同时降低脑组织中MAO活力。提示平贝母多糖FUP-1具有一定的延缓衰老作用,其作用可能与其提高抗氧化酶活性和抗脂质过氧化有关。     

USE OF OZONE TO INACTIVATE MICROORGANISMS ON LETTUCE

When ozone (1.3 mM) was bubbled for 3 min in a mixture of shredded lettuce and water, counts ofmesophilic andpsychrotrophic bacteria decreased 1.4 and 1.8 log₁₀ cfu/g, respectively. Counts of these microorganisms on lettuce, from a different batch, decreased 3.9 and 4.6 log, respectively, during 5 min of ozone treatment. Shredded lettuce was treated with gaseous ozone, or mixed with aqueous solution of ozone (1:20 w/w) with or without bubbles. For effective delivery of ozone, stirring (low and high speed), sonication or stomaching was applied during the ozonation. Washing the lettuce with water only decreased total count on shredded lettuce by 0.74–1.0 log cfu/g. When lettuce in a treatment chamber was flushed with gaseous ozone, the total count decreased 0.85 log cfu/g, but when vacuum was applied before the ozone flush, the total count decreased 0.96 log cfu/g. Bubbling ozone in water-lettuce mixture while sonicating, high-speed stirring, or before stomaching inactivated 1.4, 1.9 and 1.9 log cfu/g, respectively. In conclusion, bubbling gaseous ozone in water is the most effective ozonation method. Efficient ozone delivery to microorganisms on lettuce requires a combination of ozone bubbling and high-speed stir.     

IN SITU X-RAY PROBES FOR PIEZOELECTRICITY IN EPITAXIAL FERROELECTRIC CAPACITORS

ABSTRACT

Probing the piezoelectricity and ferroelectricity of thin film devices and nanostructures quantitatively has proven to be challenging because the appropriate experimental tools have had a limited range of usefulness. We show here that the piezoelectric and ferroelectric properties of epitaxial thin films can be measured quantitatively using time-resolved synchrotron x-ray microdiffraction. Microdiffraction combines structural specificity with the appropriate spatial resolution and ability to probe structures with electrical contacts. Our measurements of piezoelectric coefficients and coercive electric fields for Pb(Zr,Ti)O₃ capacitors using this approach are in excellent quantitative agreement with results obtained electrically and mechanically. The time and spatial resolution of microdiffraction probes are well-defined and decoupled from electrical and mechanical resonances of the ferroelectric capacitor.     

孤岛运行方式下微电网储能系统能量成型控制策略

在分析微电网储能系统(ESS)结构的基础上,建立了微电网ESS的端口受控哈密顿(PCH)模型,设计了PCH控制器,确定了期望平衡点,给出了微电网ESS的能量成型控制策略。建立含可再生能源发电单元和ESS的微电网仿真模型对所提策略进行仿真,仿真结果表明,与典型PI闭环线性控制策略相比,所提控制策略在孤岛运行期间能很好地满足对ESS的控制要求,且具有更好的快速性、鲁棒性。