Leonurine,an improved synthesis

Summary Leonurine (1) is the uterotonic principle ofLeonurus artemisia. We have developed a simple, high-yield synthetic procedure of1 that is adaptable to large scale preparation. The synthesis involves the condensation of syringic acid and 4-guanidino-1-butanol hydrochloride in the presence of DDC using 11 HMPT-ether as solvent. The synthetic leonurine showed uterotonic activity in vivo and in vitro.Acknowledgment. This work was partly supported by World Health Organization, Geneva, Switzerland.     

Leonurine, an improved synthesis.

Leonurine (1) is the uterotonic principle of Leonurus artemisia. We have developed a simple, high-yield synthetic procedure of 1 that is adaptable to large scale preparation. The synthesis involves the condensation of syringic acid and 4-guanidino-1-butanol hydrochloride in the presence of DDC using 1:1 HMPT-ether as solvent. The synthetic leonurine showed uterotonic activity in vivo and in vitro.     

THE OFFSHORE DIRECT INVESTMENT OF HONG KONG CLOTHING FIRMS

Hong Kong clothing firms have invested overseas from as early as the late 1950s in order to evade or minimise the impact of quantitative restrictions for export to developed countries. Under global trading and production involvement, the Offshore Direct Investment (ODI) activities of Hong Kong clothing firms have actually spread and penetrated into the clothing industry of different continents in the world. This paper studies empirically on Dunning's eclectic model for the offshore investment of Hong Kong clothing firms with emphasis on the rationale behind the shift and the locations chosen for initial and recent investments.     

DEVELOPMENT MODEL OF TEXTILE COMPLEX -A CASE OF HONG KONG

Experience of industrialized countries revealed that there exists a generalized pattern in the development of textile complex in the world. A model proposed by Toyne et al. was found to be generally acceptable. However, the development of this model was primarily based on observation rather than supported by empirical evidence. It is the aim of this research, by using the generalized model, to determine the development pattern of the Hong Kong textile complex. It was revealed that the local development process had both conformance and inconsistencies when compared with the model. The inconsistencies, in particular, provide implications to the application of the model in describing the global situation.     

大型气液固循环流化床中相含率分布研究

试验以水和空气为气液相,煤粉为固相研究了操作条件对直径1m、高9m大型冷模三相循环流化床中相含率轴向分布的影响。采用压降法测定气含率,抽吸取样方法测定床层中固相的局部固体浓度。结果表明,在实验范围内固体颗粒在系统中分布均匀,处于良好流化状态;根据实验提出了预测固体浓度的模型,模型预测与实验数据相符很好,可供反应器实用设计参考。     

A Newtonian approach to extraordinarily strong negative refraction

Metamaterials with negative refractive indices can manipulate electromagnetic waves in unusual ways, and can be used to achieve, for example, sub-diffraction-limit focusing, the bending of light in the 'wrong' direction, and reversed Doppler and Cerenkov effects. These counterintuitive and technologically useful behaviours have spurred considerable efforts to synthesize a broad array of negative-index metamaterials with engineered electric, magnetic or optical properties. Here we demonstrate another route to negative refraction by exploiting the inertia of electrons in semiconductor two-dimensional electron gases, collectively accelerated by electromagnetic waves according to Newton's second law of motion, where this acceleration effect manifests as kinetic inductance. Using kinetic inductance to attain negative refraction was theoretically proposed for three-dimensional metallic nanoparticles and seen experimentally with surface plasmons on the surface of a three-dimensional metal. The two-dimensional electron gas that we use at cryogenic temperatures has a larger kinetic inductance than three-dimensional metals, leading to extraordinarily strong negative refraction at gigahertz frequencies, with an index as large as -700. This pronounced negative refractive index and the corresponding reduction in the effective wavelength opens a path to miniaturization in the science and technology of negative refraction.     

Multifunctional cationic host defence peptides and their clinical applications

With the rapid rise in the emergence of bacterial strains resistant to multiple classes of antimicrobial agents, there is an urgent need to develop novel antimicrobial therapies to combat these pathogens. Cationic host defence peptides (HDPs) and synthetic derivatives termed innate defence regulators (IDRs) represent a promising alternative approach in the treatment of microbial-related diseases. Cationic HDPs (also termed antimicrobial peptides) have emerged from their origins as nature’s antibiotics and are widely distributed in organisms from insects to plants to mammals and non-mammalian vertebrates. Although their original and primary function was proposed to be direct antimicrobial activity against bacteria, fungi, parasites and/or viruses, cationic HDPs are becoming increasingly recognized as multifunctional mediators, with both antimicrobial activity and diverse immunomodulatory properties. Here we provide an overview of the antimicrobial and immunomodulatory activities of cationic HDPs, and discuss their potential application as beneficial therapeutics in overcoming infectious diseases.     

U型钢与喷网支护壁后充填注浆加固

介绍U型钢支架的应用特点及及巷道修复工程中存在的问题，提出采用水泥－粉煤灰浆液和水泥－水 玻璃浆液对支架壁后进行充填和注浆加固，取得了较好的技术经济效果，为壁后存在较大空隙巷道的稳定提供了一种较好的支护与加固手段。     

Investigation in Longitudinal Compression of Wool Based Suiting Fabrics

This paper describes an investigation in the fabric longi-tudinal compressibility of thirty-one suiting and trouse-ring materials using a newly developed device attached to the advanced Instron extensometer Model4466.The at-tachment was designed mainly to ensure a correct align-meat of fabric plane at the start of compression.Usingthe newly developed testing method,fabric longitudinalcompression curve was obtained and the results of longi-tudinal compressibility measured by two different com-pression load ranges(from 0 to 0.5 N/m width and 0 to1 N/m width)were examined.In addition,their rela-tionships with the fabric low-stress mechanical proper-ties measured by the KES-F system were investigatedusing statistical analysis.The results clearly indicatedthat significant differences existed when substituting fab-ric longitudinal compressibility with fabric extensibilitymeasured using the KES-F system under a low-load.Significant infiuence of yarn rotational movement in fab-ric on the longitudinal compressibi     

Perfluorooctane sulfonate （PFOS） and related fluorochemicals in chicken egg in China

The ubiquitous occurrence of perfluorinated compounds （PFCs） in environmental samples has drawn much attention. Recent human exposure studies found relatively high perfluorooctane sulfonate （PFOS） concentrations in blood samples from several cities in China when compared with other countries. The objectives of the present study were： （1） to measure PFC concentrations and compositions in chicken egg samples from local markets in China; and （2） to conduct a preliminary human health risk assessment of egg consumption. Eight pooled egg samples from eight locations were analyzed for 11 PFCs. The results showed that close to 100% of the PFOS in the egg was distributed in egg yolk and PFOS was not detected in egg white （〈0.08 ng/g wet weight, w/w）. Of the perfluoroalkylsulfonates, only PFOS was detected in all egg samples, while of the perfluoroalkylcarboxylates, perfluoroundecanoic acid （PFUnDA） was detected in all samples, followed by perfluorooctanoate （PFOA） （75% occurrence） and perfluorodecanoic acid （PFDA） （50% occurrence）. PFOS concentrations in egg ranged from 45.0 to 86.9 ng/g w/w. The results suggested that current concentrations of PFOS in domestic chicken eggs are unlikely to cause immediate harm to Chinese populations.