Kinetic and electrical phenomena in gas–liquid systems

Disperse systems consisting of a liquid and gas bubbles located in it are considered. Two possible versions of evolution of bubbles under the conditions studied are assessed. In simple liquids, contact between two bubbles causes them to merge, as the separating film breaks. In the case of complex organic liquids, amphiphilic film is formed on the surface of bubbles, and the lifetime of bubbles in contact increases with their size. Under an external electric field, chains of bubbles are formed, lined up along the electric field potential lines. The presence of bubbles in liquid greatly lowers the breakdown threshold, as the critical parameters of the breakdown field in liquids are two to three orders of magnitude higher than those in gases at atmospheric pressure. Various breakdown mechanisms in liquids are discussed from the viewpoint of formation of the gas phase during the passage of an electric current through a liquid medium. The character of propagating a streamer in separate bubbles is studied with their random distribution in liquid and in the case of formation of some structures of bubbles; the critical parameters of disperse systems, that can lead to their electrical breakdown, are presented. Along with the general concepts of electrical breakdown in dispersed systems, experimental studies of these processes are considered, and the nature of electrical breakdown in liquid dielectrics, including transformer oil, is discussed.     

Stable,Efficient, Single-mode Operation of a High Repetition Rate Grazing Incidence Dye Laser

Abstract

A pulsed, grazing incidence dye laser has been designed to oscillate at a repetition rate of 6·5 kHz in a single, narrow and stable, axial mode with a high excitation conversion efficiency. A single mode efficiency of 12% has been measured in a near diffraction limited beam. No measurable fluctuations of the central laser wavelength or the 100–150 MHz single mode linewidth were observed during an hour of observation. The effect of grating incident angle and dye flow rate on laser operation have been investigated and a correlation has been found between the state of polarization of the dye laser output and the polarization of the pump laser.     

Early development of spiny neurons in fish and mouse: morphometric measures of dendritic spine formation pattern

Positions of spines on apical dendrites were evaluated using 4 pattern analysis techniques: spine counts, variance/mean ratio, Lloyd's patchiness index, and nearest neighbor distance matrix. Spiny tectal interneurons from jewel fish (100, 130, 160 and 1550 days old), and layer V pyramidal cells in layer IV auditory cortex of CBA/J mice (100 and 450 days old) were studied. Fish's spines became more numerous and more clumped on distal dendritic strata during development, while mice lost dendritic spines with age. Both species developed a significantly regular spacing pattern between neighboring spines during development. These changes are explained in the context of spine function and a biophysical model of dendritic spine patterns.     

Are exaggerated health complaints continuous or categorical? A taxometric analysis of the Health Problem Overstatement Scale.

A taxometric analysis of 3 factor scales extracted from the Health Problem Overstatement (HPO) scale of the Psychological Screening Inventory (PSI; R. I. Lanyon, 1970, 1978) was performed on the data from 1,240 forensic and psychiatric patients. Mean above minus below a cut, maximum covariance, and latent-mode factor analyses produced results indicative of dimensional latent structure for the exaggerated health complaints construct. The outcome of this and several other recent taxometric investigations indicates that across 3 different domains of feigning (i.e., psychiatric symptoms, memory problems, and health complaints), the overall feigning construct is ordered continuously along 1 or more dimensions rather than partitioned into discrete categories of malingerers and nonmalingerers. These findings call for more research on the extent to which the different domains of feigning share 1 or more dimensions in common. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An adaptation of the theory of interpersonal behaviour to the study of telemedicine adoption by physicians

Physicians' acceptance of telemedicine constitutes a prerequisite for its diffusion on a national scale. Based upon the Theory of Interpersonal Behavior, this study was aimed at assessing the predictors of physicians' intention to use telemedicine in their clinical practice. All of the physicians involved in the RQTE, the extended provincial telemedicine network of Quebec (Canada) were mailed a questionnaire to identify the psychosocial determinants of their intention to adopt telemedicine. Confirmatory factor analysis (CFA) was performed to assess the measurement model and structural equation modelling (SEM) was applied to test the theoretical model. The adapted theoretical model explained 81% (P<0.001) of variance in physicians' intention to use telehealth. The main predictors of intentions were a composite normative factor, comprising personal as well as social norms (beta=1.08; P<0.001) and self identity (beta=-0.33; P<0.001). Thus, physicians who perceived professional and social responsibilities regarding adoption of telehealth in their clinical practice had stronger intention to use this technology. However, it is likely that personal identity had a suppression effect in the regression equation, indicating that physicians' intention to use telemedicine was better predicted if their self-perception as telemedicine users was considered. These results have several implications at the theoretical and practical levels that are discussed in this paper.     

The impact of antigen density and antibody affinity on antibody-dependent cellular cytotoxicity: relevance for immunotherapy of carcinomas

We studied the sensitivity of human melanoma (Bro strain) xenografts to drugs of the nitrosoalkylurea (NAU) class: nitrosomethylurea (NMM), karmustin (BCNU), nimustin (ACNU), nitrulin, and ADEKO. High antitumor activity of NAM was shown when the drugs were applied not only at the early, but also at the late stages of tumor progression (tumor mass 400 and 1200 mg, respectively). The therapeutic effect of the drugs was estimated with the use of criteria characterizing the kinetics of tumor regression, increased life span, and survival of treated animals. After early administration of the drugs (Day 4 after tumor transplantation), 67% and 50% of animals survive under the influence of nitrulin and ACNU, respectively, while the rate of tumor regression increased in the sequence nitrulin < karmustin < NMM < ACNU. After late administration (11 days after tumor transplantation), NMM was most effective at increasing survival (35% of survived animals by 35 days of observation), while the rate of tumor regression increased in the sequence ADEKO < NMM < karmustin < nitrulin < ACNU.     

A specific light chain of kinesin associates with mitochondria in cultured cells

High-resolution two-dimensional gel electrophoresis (2-DE) and database analysis was used to establish protein expression patterns for cultured normal human mammary epithelial cells and thirteen breast cancer cell lines. The Human Breast Epithelial Cell database contains the 2-DE protein patterns, including relative protein abundances, for each cell line, plus a composite pattern that contains all the common and specifically expressed proteins from all the cell lines. Significant differences in protein expression, both qualitative and quantitative, were observed not only between normal cells and tumor cells, but also among the tumor cell lines. Eight percent (56/727) of the consistently detected proteins were found in significantly (P< 0.001) variable levels among the cell lines. Eight proteins present in normal cultured breast epithelial cells were not detected in any of the tumor cell lines. We identified a subset of the differentially expressed proteins using a combination of immunostaining, protein sequencing, comigration, and subcellular fractionation. These identified proteins include the intermediate filament components vimentin and cytokeratins. The cell lines can be classified into four distinct groups based on their intermediate filament protein profile. We also identified heat shock proteins; hsp27 and hsp60 varied in abundance and in some cases in the relative phosphorylation levels among the cell lines. Many of the differentially expressed proteins we identified have roles in cellular proliferation and differentiation, including annexin V, elongation initiation factor 5A, Rho GDP dissociation inhibitor, and prohibitin. We identified inosine-5-monophosphate dehydrogenase in each of the cell lines, and found the levels of this enzyme in the tumor cell lines elevated 2- to 20-fold relative to the levels in normal cells. These results expand the human breast epithelial cell protein database (http:// www.anl.gov/CMB/PMG) which is being built to assist researchers with the identification of abnormal patterns of expression and pathways associated with malignancy.     

Respiratory depression following administration of intrathecal bupivacaine to an opioid-dependent patient

OBJECTIVE: To document two cases of respiratory depression in patients receiving morphine once the stimulating effect of pain on respiration was removed by bupivacaine. CASE SUMMARIES: Case 1: A 72-year-old 84-kg white man with cancer of the bladder and bone metastases had intense back and leg pain that was treated with intrathecal morphine for 6 months at an increasing dosage up to 10 mg twice daily. The intrathecal route was avoided for 4 days because of a suspected local infection at the site of the intrathecal catheter. During this 4-day period the patient received extended-release morphine and subcutaneous morphine daily. When the intrathecal route was used again, he received an identical dose of morphine plus bupivacaine and epinephrine. Ten minutes after the injection, fatal respiratory distress occurred. Case 2: A 92-year-old white woman was admitted for revascularization of arteritis on her left leg. To treat a painful sacrum and heel bedsores, she received extended-release oral morphine for 8 days. Induction of the intrathecal anesthesia was performed with bupivacaine. After 10 minutes, the patient became subcomatose, with miosis and apnea. Intravenous naloxone restored spontaneous respiration and normal consciousness. CONCLUSIONS: Pain is a physiologic antagonist of the respiratory depressant effects of opioid analgesics. By reducing pain stimulation, bupivacaine may make patients more susceptible to opioid respiratory depression. Such situations require titration of bupivacaine and other analgesics as well as increased monitoring of the patient.