商业生产条件下的最佳维生素营养

日粮中添加维生素不再只是为了预防缺乏症的问题。最近的研究表明，日粮含较高水平的维生素可使现代动物表现其遗传潜力。维生素与氨基酸不同，氨基酸可按其限制性分类，而对维生素则应予以综合考虑。     

马铃薯晚疫病菌在水及土壤中存活期限和状态的初步观察

初步试验和观察结果表示马铃薯晚疫病菌在无定形的原生质团状态下能相当长时期地在水和土壤中保存其生活力。将病薯上的病菌接种于薯块切面上,大量繁殖后作如下处理:(1)用针将孢子囊挑入冷开水或普通自来水中,保存于20℃的温箱内。(2)将孢子囊冲洗到普通自来水中,稀释为每低倍镜视野含有60个孢子囊的悬浮液,倒入花盆内的轻松     

广州地区十字花科蔬菜花叶病第三类病原病毒的鉴定

广州地区十字花科蔬菜花叶病第三类病原病毒的物理性质与TMV基本相似:失毒温度86—90℃之間,寄主体外存活期限37个月以上,稀释終点1:10000—50000之間。本病毒易由液汁接触传染,可由斜纹夜盜蛾、菜粉蝶和甘蓝夜蛾的2—3龄幼虫、普通紅蜘蛛以及中国菟絲子传染。但不能由桃蚜、蘿卜蚜、黃条跳(虫甲)成虫以及感病蔬菜的种子传染。在含新鮮病菜組織的土壤中移植蔬菜,可引起部分蔬菜感染发病。本病毒的寄生范围較广。在供試植物20科49屬93个种和品种中,能侵染十字花科、茄科、菊科、藜科、莧科、車前草科和石竹科植物等7科18屬54种和品种。交互保护試驗結果,TMV(毒株23号)对本病毒只有小部分的保护作用。但根据周家熾、田波等試驗結果認为本病毒与TMV有一定的血清学关系,因此暫把此病毒列入TMV类羣中,作为一个远缘的毒株。     

Hypoglycemic effects of vanadium on alloxan monohydrate induced diabetic dogs

The hypoglycemic effects after oral administration of vanadium have been studied previously in many species such as rats, mice and even humans. However, there has been no prior report on the glucose lowering effect of vanadium on diabetic dogs. Therefore, the purpose of this study was to evaluate the hypoglycemic effects of oral vanadium on diabetic dogs. Diabetes mellitus in the dogs studied was induced by alloxan monohydrate intravenous injection. The dogs were divided into two groups, one was the diabetic control (DC) group (n = 4) and the other was the vanadium treated (DV) group (n = 6). Fresh water was supplied to the dogs in the DC group, but sodium metavanadate solution (0.1~0.2 mg/ml) was given to the dogs in DV group from one week after the alloxan injection. The fasting glucose levels, fructosamine and serum chemistry profiles were compared between the two groups weekly for three weeks. The fasting blood glucose levels in DV group were significantly lower than those in the DC group (p < 0.01). Fructosamine levels in the DV group were also lower than those in the DC group (p < 0.05). The serum chemistry profiles were not significantly different in comparisons between the two groups. However, the cholesterol levels were significantly lower in the DV group compared to the DC group (p < 0.05). Our findings showed that oral vanadium administration had a hypoglycemic effect on chemically induced diabetic dogs.     

Epidemiological characteristics and financial costs of the 1997 foot-and-mouth disease epidemic in Taiwan

Between March and July 1997, a devastating outbreak of foot-and-mouth disease (FMD), serotype O, occurred in pigs in Taiwan. A total of 6,147 pig farms with more than 4 million pigs were infected, and 37.7 per cent of the pigs in Taiwan either died (0.18 million pigs) or were killed (3.85 million pigs). The epidemic reached its peak during the fifth week after it was first recognised. During the eighth and ninth weeks, a two-dose blanket vaccination programme was instituted which led to a large reduction in new outbreaks. Except for two cities, the whole of Taiwan was declared an FMD-infected zone. During the four months in which new farm outbreaks occurred, 21.7 per cent of the pigs on infected farms showed clinical signs, and there was an overall mortality of 3.95 per cent. During the early stages of the epidemic, the incubation period was as short as 24 hours and the case fatality rates for suckling piglets reached 100 per cent. The financial cost of the epidemic was estimated at US$ 378.6 million, including indemnities, vaccines, carcase disposal plus environmental protection, miscellaneous expenses, and loss of market value. Owing to the ban on exports of pork to Japan, it is estimated that the total economic cost to Taiwan's pig industry will be about US$ 1.6 billion.     

From followers to market leaders: Asian electronics firms in the global economy

Abstract: This paper aims to explain how a number of leading electronics firms from Asian newly industrialised economies of Hong Kong, Singapore, South Korea and Taiwan are articulated into global production networks and become major players in their respective market niches. Developing a triangular theoretical framework, I seek to explain the complex relationships between the dynamic articulation of these leading Asian electronics firms into different global production networks and their simultaneous upgrading from typical followers to market leaders. As a critique of the dominant developmental state discourse, I argue that the interplay between corporate strategies and home base advantages within the context of changing global production networks can offer a better explanation of the differentiated competitive outcomes of these Asian firms. This paper draws upon original data collected through personal interviews with top executives from leading electronics firms in the four Asian newly industrialised economies. I conclude the paper with some implications for theory and policy in relation to corporate development in Asian economies.     

The preparation of polyurethane foam combined with pH-sensitive alginate/bentonite hydrogel for wound dressings

Polyurethane (PU) foam was combined with protein drug-loaded pH-sensitive alginate-bentonite hydrogel for wound dressings. Alginate is a linear copolymer composed of 1–4-linked β-D-mannuronic acid (M) and its c-5-epimer α-Lguluronic acid (G). The amount of (M) and (G) and their sequential distribution are varied depending on the alginate source. Soluble sodium alginate can become a hydrogel when cross-linked with divalent cations and has widespread applications in the food, drink, pharmaceutical and bioengineering industries. Recently, it has been also proposed as a biomaterial for drug delivery systems. Bentonites are the natural inorganic polymers consisting of a large proportion of expandable clay minerals with a three-layer structure such as montmorillonite, beidellite, nontronite, etc. They are important adjutants and supports for medical products, and they have many useful physicochemical, mechanical, and biological properties such as absence of toxicity, indifference to other raw materials, sorption, swelling, and complex formation properties. Alginate-bentonite hydrogels were prepared at concentration ratios of 10/0, 7/3, 5/5, 3/7. PU foams were prepared using hydrophilic polyols. We investigated the controlled release of a protein drug from PU foam combined with alginate-bentonite hydrogel at different pH values of 4.2, 5.2, 7.2, 8.2. The mechanical properties and cytotoxicity tests of this foam were also studied.     

Promising antidiabetic potential of fucoxanthin isolated from the edible brown algae Eisenia bicyclis and Undaria pinnatifida

In the present study, we investigated the antidiabetic potential of fucoxanthin via the inhibition of rat lens aldose reductase (RLAR), human recombinant aldose reductase (HRAR), advanced glycation end-product (AGE) formation, protein tyrosine phosphatase 1B (PTP1B), and α-glucosidase. Fucoxanthin displayed potent inhibitory activity against AGE formation and HRAR and RLAR activity. In addition, fucoxanthin showed potent inhibitory activity against PTP1B. However, it did not show α-glucosidase inhibitory activity below 200 μM. In addition, our kinetic study revealed that fucoxanthin competitively inhibited RLAR, while it showed mixed-type inhibition against PTP1B. In order to confirm enzyme inhibition, we predicted the 3D structure of PTP1B using Autodock 4.0 to simulate the binding of fucoxanthin. Docking simulation results demonstrated that three residues of PTP1B (Phe30, Phe52, and Gly183) interact with the two hydroxyl groups of fucoxanthin. In addition, the binding energy was negative (?7.66 kcal/mol), indicating that the three hydrogen bonds may stabilize the open form of the enzyme and potentiate tighter binding to the active site of PTP1B, resulting in more effective PTP1B inhibition. The results of the present study therefore clearly demonstrate the promising potential of fucoxanthin as a therapeutic intervention for the management of diabetes as well as diabetes-associated complications, which could be explored further.     

Endurance of linear and cross-linked shape memory polyurethane under rigorous hydrolysis conditions

Linear shape memory polyurethane (SMPU) copolymers synthesized from 4,4′-methylene bis(phenylisocyanate) (MDI), poly(tetramethyleneglycol) (PTMG), and 1,4-butanediol (BD), and cross-linked SMPU by glycerol were being tested under the severe hydrolysis conditions for the tensile mechanical properties and the shape memory effect for 6 months. Tensile mechanical properties and shape memory effect were not substantially decreased after 6 months of storage, and SMPU structure was not affected during the long-term hydrolysis test as evidenced by IR, DSC, contact angle, and viscosity. Hydrolysis test was important in proving the durability of SMPU before application of SMPU in aqueous surrounding.