Upregulation of the surface expression of two integrins and induction of chemotactic activity in a human leukemic cell line by Oncoimmunin-M

Previously, it was shown that Oncoimmunin-M (OI-M), a recently identified tumor cell-derived 36 kDa protein, is able both to inhibit the proliferation of the human promyelocytic leukemic cell line HL-60 while maintaining viability in culture and to induce a bimodal distribution of CD11b, the alpha chain of the integrin MAC-1, on the cell surface (Packard, B.Z. and Komoriya, A. (1993) J. Biol. Chem. 268, 6356-6363). Now, data which reveal that exposure of HL-60 cells to this factor also brings about an increase in the mean level of surface expression of CD11c, the alpha chain of another leukocyte integrin (p150,95), but leaves CD11a, the alpha chain of the third leukointegrin (LFA-1), virtually unchanged (< 10%) are presented. Comparison of motility studies of OI-M-treated HL-60 bulk populations with control bulk populations demonstrates coinduction of CD11b and CD11c surface upregulation with chemotactic responsiveness to a gradient of the chemoattractant human C5a. Separation of motile from nonmotile cell subpopulations after exposure to C5a further reveals that individual cells which respond to this chemoattractant express increased levels of both CD11b and CD11c relative to unresponsive cells. These data correlate the upregulation of leukointegrins MAC-1 and p150,95 by a tumor cell-derived protein on a preterminally differentiated myeloid cell with chemotactic responsiveness to human C5a.     

Improvement of the engineering properties of asphalt pavements using a ‘soft’ compaction technique (AMIR-Compaction)

In most countries of the world asphalt pavement of road networks represents the biggest single investment in the transportation system. In Canada, asphalt pavement built over the past decade is worth more than 70 billion dollars (in 1984 dollars). In order to maintain the current road network at the present level of service and prevent it from further deterioration, over 6 billion dollars is needed anually.

Traditionally, asphalt overlays are widely used to rehabilitate existing deteriorated pavements. Unfortunately the new overlays have been observed to fail in a relatively short time. Thus the investment in overlays is lost.

Recent research based on the concept of relative rigidity has indicated that the rapid deterioration of new asphalt overlays is directly related to current construction equipment. It has been shown analytically and experimentally that steel rollers used in compacting the asphalt layer will result in surface cracks during construction. Traffic and environmental influences will accelerate the failure of the new layer.

This paper presents the results of a testing programme evaluating the engineering properties of asphalt slabs compacted by a new method using a compactor termed AMIR. The results showed that the AMIR compactor will prevent the formation of constitution cracks resulting in an increase of indirect tensile strength of 10% and an increase of direct tensile strength of up to 60% when compared to steel roller compacted asphalt slabs.     

Distribution of prostaglandin IP and EP receptor subtypes and isoforms in platelets and human umbilical artery smooth muscle cells

Prostaglandins act through specific receptors to stimulate cyclic AMP formation which inhibits platelet activation and relaxes vascular smooth muscle. We have used RT-PCR combined with Southern blot analysis to determine the subtypes of prostaglandin receptor on platelets. Platelets expressed the EP4 rather than the EP2 prostaglandin EP receptor subtype, whereas vascular smooth muscle cells predominantly expressed the EP2 receptor. The IP receptor, which binds prostacyclin and couples to stimulation of adenylyl cyclase, and three isoforms of the inhibitory EP3 receptor were equally expressed in platelets, HEL cells and umbilical artery smooth muscle cells. The EP3-II isoform showed variation in level of expression among the three cell types. As a positive control for the presence of platelet RNA, PCR was performed using primers specific for the alpha chain of the platelet membrane glycoprotein Ib. As a negative control for the absence of T and B cell contamination in the platelet RNA, PCR was performed using primers specific for the cell specific cluster determinants CD2 (a T-cell marker) and CD20 (a B-cell marker). The finding that platelets express both stimulatory and inhibitory prostaglandin receptors provides confirmation of a homeostatic model of regulation of platelet adenylyl cyclase previously proposed.     

Illness and injury in family day care: a seasonal survey

Many mothers with children under age 6 are employed and it is not usually feasible for a parent to stay home with a child who is mildly ill. Such ill children likely remain in child day care programs. The extent to which this occurs and the management of these children in family day care was studied. Over the course of a year, 1 to 3 visits were made to 714 family day care homes in order to survey providers. With enrollments ranging between 0 and 18 children per day care home at the time of each visit, information on 3,630 "child enrollment days" was collected. The median age of children in care was 2 years. An average of 16% of all children were ill on any one day (with seasonal variation); 1% were injured. Of ill children, 82% attended day care that day, 49% had contacted a physician about that illness, and 28% were administered a medication at the day care setting. Twenty-one percent of children receiving medication in day care had no contact with a physician for that illness. These data show that mild childhood illnesses are routinely managed by child day care providers. Physicians who traditionally limit their illness-management education to parents need to recognize the health education and consultation needs of day care providers.     

Effect of shot noise and secondary emission noise in scanning electron microscope images

The effect of shot noise and emission noise due to materials that have different emission properties was simulated. Local variations in emission properties affect the overall signal‐to‐noise ratio (SNR) value of the scanning electron microscope image. In the case in which emission noise is assumed to be absent, the image SNRs for silicon and gold on a black background are identical. This is because only shot noise in the primary beam affects the SNRs, irrespective of the assumed noiseless secondary electron emission or backscattered electron emission processes. The addition of secondary emission noise degrades the SNR. Materials with higher secondary electron yield and backscattering electron yield give rise to higher SNR. For images formed from two types of material, the contrast of the image is lower. The reduction in image signal reduces the overall image SNR. As expected, large differences in δ or η give rise to higher SNR images.     

Raft crystals of poly(isoprene)-block-poly(ferrocenyldimethylsilane) and their surface wetting behavior during melting as observed by AFM and NanoTA

We report on the morphology evolution during heating and melting of lamellar poly(isoprene)-block-poly(ferrocenyldimethylsilane) (PI₇₆-b-PFDMS₇₆) raft crystals deposited at the native oxide surface of silicon (SiO₂) or at a highly ordered pyrolytic graphite (HOPG) surface, studied by in situ temperature controlled atomic force microscopy. Crystals deposited on hydrophilic SiO₂ surfaces revealed an irreversible decrease in length at temperatures of up to tens of degrees above their expected melting temperature, while maintaining their platelet-like structure. Crystals deposited on hydrophobic HOPG surfaces initially decreased in length below their expected melting temperature, while at 120 °C and above a typical molten morphology was observed. In addition, the irreversible formation of a PI₇₆-b-PFDMS₇₆ wetting layer around the crystals was observed upon increasing the temperature. These observations in the morphological behavior upon heating emphasize the role of interfacial energy between a surface deposited block copolymer based macromolecular nanostructure and its supporting substrate.     

变压发泡工艺对聚氨酯泡沫泡孔结构控制的研究

利用变压发泡可实现对聚氨酯泡沫泡孔结构的控制,得到气孔细密均匀的泡沫体。主要探讨了变压发泡工艺下,恒压时间、压力大小对泡沫泡孔结构的影响     

取代苯甲酸葡萄糖酯的合成及生物活性

以两种方法合成了10个取代苯甲酸葡萄糖酯类化合物，一是相转移催化法，二是在三忆胺的存在下，取代苯甲酸与溴代葡萄糖反应，该种合成糖酯的方法未见文献报道，取代苯甲酸葡萄糖酯的结构由IR、MS、^1H NMR和元素分析确认。对化合物的抗病毒活性测试结果发现，其中有两个化合物具有一定的抑制TMV的活性。     

Comparative Analysis of Scanning Electron Microscopy Techniques for Semiconductors: Electron-Beam-Induced Potential Method,Single-Contact Electron-Beam-Induced Current Method,and Thermoacoustic Detection

The potentialities of three techniques for detecting signals from barrier structures in a scanning electron microscope are discussed. All the methods are virtually contactless; that is, it is only required that the chips are grounded. The relaxation behavior of the signals is considered. The invalidity of the thermoacoustic detection technique is shown. It is experimentally demonstrated that information extracted with the method of electron-beam-induced surface potential is identical to that obtained by thermoacoustic detection.