环保与行业组织

环境保护法规关系一个国家履行的职责,维系整个国家的经济繁荣。在民众环境保护呼声日益高涨的美国,环境保护已经成为政府职能不可或缺的一部分,但推行的结果却不令人满意。原因是认为环保法规不科学,没有协调好环境与社会需求的关系;而政府迫于舆论的压力采取的强制法规难免不使企业陷入难堪的境地。为此,政府与企业之间的环保争议时有发生。为协调政府与企业之间的纷争,美国涂料协会主席兼国际涂料与印墨理事会秘书长J.Anerew Doyle先生认为,应加强行业组织在政府立法中的作用,使环保法规更加科学、合理。国际涂料与印墨理事会一直致力于使自己成为联合国属下的非政府组织,并力争代表国际涂料与印墨工业对环保立法产生影响。     

Ultrasonically enhanced persulfate oxidation of polyethylene surfaces

The ultrasonically enhanced oxidation of polyethylene surfaces by potassium and ammonium persulfates is described. The use of ultrasound allows significant levels of surface modification to be achieved using these oxidizing agents under mild conditions. Changes in the water contact angle and attenuated total reflection infra-red spectra were used to follow the changes in surface chemistry. Variation of conditions such as sonication time, sound intensity and reaction temperature allowed control over the extent and nature of the surface oxidation.     

Production and characterization of anti-human interferon {gamma} receptor antibody fragments that inhibit cytokine binding to the receptor

Three single-chain antibody fragments that recognize the extracellularhuman interferon receptor -chain (IFNR), and inhibit the bindingof human IFN, have been produced in Escherichia coli. Thesefragments are derived from murine anti-receptor monoclonal antibodies,and comprise the variable heavy (V_H) domain linked to the variablelight (V_L) chain through a 15 amino acid linker [(GGGGS)₃].Using surface plasmon resonance technology (BIAcore), the solubleproteins were shown to retain a high affinity for recombinantIFNR, and by radioimmunoassay to possess high inhibitory activitytowards IFN-binding to human Raji cells. The antibody fragmentsmost likely recognize epitopes that overlap the cytokine bindingsite on the receptor surface. Attempts to dissect further theantibodies to isolated V_H- and V_L-chains and to synthetic linearand cyclic peptides derived from the individual complementaritydetermining regions failed to afford fragments with significantIFNR binding affinity. Nevertheless, these native-like variableregion fragments and petidomimetics derived from them are ofinterest in the design of novel IFNR antagonists.     

Glucan-Protein Interactions. Gelatin-Induced Solubilization of Glycogen in Alcohol-Water Solutions

In organic solvents, gelatin can induce the solubilization of glycogen and other polysaccharides. It was shown that the solubilization reaction was mediated through polysaccharide-protein hydrogen bonds. Glycogen-gelatin binding was influenced by the relative concentration of glycogen to the protein. The induced solubilization of glycogen was partially inhibited by temperatures above 0 °C. Water was shown to inhibit glycogen-gelatin interactions in acidified methanol, ethanol, n-propanol and tertiary butanol. In general, it was found that the most hydrophobic alcohols were the best solvents for the glycogen-gelatin solubilization reaction. The solubility of the glycogen-gelatin complex was determined and found to be 0.22 mg/ml. The presence of strong acids tended to inhibit complex formation while weak acids promoted the solubilization reaction. A method for the fractionation of gelatin into distinct molecular weight classes was developed by use of a methanol-phenol solvent system. High molecular weight gelatins were better glycogen solubilizing agents than low molecular weight gelatins.     

Novel Aspects of the Liver Microenvironment in Hepatocellular Carcinoma Pathogenesis and Development

Hepatocellular carcinoma (HCC) is a prevalent primary liver cancer that is derived from hepatocytes and is characterised by high mortality rate and poor prognosis. While HCC is driven by cumulative changes in the hepatocyte genome, it is increasingly recognised that the liver microenvironment plays a pivotal role in HCC propensity, progression and treatment response. The microenvironmental stimuli that have been recognised as being involved in HCC pathogenesis are diverse and include intrahepatic cell subpopulations, such as immune and stellate cells, pathogens, such as hepatitis viruses, and non-cellular factors, such as abnormal extracellular matrix (ECM) and tissue hypoxia. Recently, a number of novel environmental influences have been shown to have an equally dramatic, but previously unrecognized, role in HCC progression. Novel aspects, including diet, gastrointestinal tract (GIT) microflora and circulating microvesicles, are now being recognized as increasingly important in HCC pathogenesis. This review will outline aspects of the HCC microenvironment, including the potential role of GIT microflora and microvesicles, in providing new insights into tumourigenesis and identifying potential novel targets in the treatment of HCC.     

Comparison of flavor compounds of potato chips fried in palmolein and silicone fluid

The importance of the frying oil as a heat-transfer medium and as a source of flavor precursors for the formation of potato chip flavor was investigated. Potato slices were fried in palmolein or silicone fluid, and the volatile flavor compounds of the resulting chips were isolated onto Tenax and analyzed by gas chromatography-mass spectrometry. Although the heat-transfer coefficients of the oils did not differ significantly, their temperature profiles during frying were different, probably due to greater turbulence on placing potato slices in palmolein, leading to more efficient heat transfer. Levels of Strecker aldehydes and sulfides in chips fried in the two media were not significantly different, but levels of pyrazines were significantly higher in palmolein-fried chips. Amounts of 2,4-decadienal were also significantly higher in palmolein-fried chips, but there was no significant difference in hexanal levels between the samples.     

Control-affine neural network approach for nonminimum-phase nonlinear process control

The design of controllers for nonlinear, nonminimum-phase processes is very challenging and remains as one of the more difficult control research problems. Most currently available control algorithms rely implicitly or explicitly upon an inverse of the process. Linear control methods for nonminimum-phase processes are typically based on a decomposition of the process into a minimum-phase and a nonminimum-phase part, and subsequent inversion of the minimum-phase component. A similar scheme for nonlinear systems is still an open problem. In this work, an internal model control strategy employing a minimum-phase model is proposed. The minimum-phase model is first-order, minimum-phase and control-affine but statically equivalent to the original process. Because the model is identified directly from input-output data, a first principles model of the process is not required. The inverse of the process is obtained through analytical inversion of the process model. The proposed control scheme is applied to a van de Vusse reactor and a complex continuous stirred tank bioreactor.     

Animate Characters

The world of everyday interactions is filled with characters, real or fictitious, and human knowledge of how to make these interactions satisfying and productive relies upon an understanding of character. As agents become more intelligent and more ubiquitous, we may naturally ask how we can endow them with life and personality to make them easier and more gratifying to use. This paper offers a broad definition of animate character, and examines the technical and artistic issues involved both in the creation and the evaluation of such systems. We provide example interactions with several character types. The paper concludes with an annotated bibliographic survey of work done in this area.