Plane deformation characteristics of compressible materials

Conclusions The plane deformation of metal powders and porous solids analyzed with resort to the approximation of an ideal plastic solid is described by a system of differential equations and partial derivatives which can be of the hyperbolic, parabolic, or elliptic type. The characteristics of the equations (when they are present) are lines along which the material experiences no elongation. Regions containing these lines exist during shaping under conditions of a well-developed free surface (the equations are of the hyperbolic type); in omnidirectional compression and compression in shells, in the absence of a free surface, there are no such zones (the equations are of the elliptic type).Translated from Poroshkovaya Metallurgiya, No. 3(231), pp. 14–21, March, 1982.The author wishes to thank Professor B. A. Druyanov for helpful discussion.     

Evaluation of the Respiralex test for rapid isolation of Streptococcus pyogenes directly from throat swabs

Results obtained by fast Respiraplex test were compared with findings of classical method of cultivation in order to assess possibilities of this test in isolation of Streptococcus pyogenes directly in the throat swab. The sensitivity of the fast test was 79.4%; specificity 100%. On the basis of gathered results, the following can be concluded: the fast test cannot completely substitute the classic method of cultivation although high specificity occurs, because of low sensitivity especially in patients with small number of colonies in the culture.     

Optimisation of sample presentation for the near-infrared spectra of pharmaceutical excipients

The two most common forms of hereditary ovarian cancer are: the breast ovarian cancer syndrome, and ovarian cancer associated with HNPCC (hereditary nonpolyposis colorectal cancer) syndrome. Studies have shown that these diseases may be associated with mutations in a number of tumor suppressor genes, mainly BRCA1 and BRCA2. Malfunction of the protein products of these genes have also been found to be involved in sporadic ovarian cancer, which makes up the majority of ovarian cancer cases. HNPCC-ovarian cancer associated families reveal frequent mutations in at least four genes (hMSH2, hMLH1, hPMS1, and hPMS2) involved in the repair of mismatched DNA. With ovarian cancer being such an important health issue, the push is on to design reliable screening tests to detect defective inherited or somatic alleles in individual carriers. So far, most progress has been demonstrated in those patients with family histories of the disease who are at increased risk. The ramifications of such research may impact a variety of scientific, clinical, legal, ethical, and psychosocial issues. In addition to current treatment modalities, positive results of these tests may indicate the need for increased clinical surveillance, prophylactic treatment, and genetic counseling of patients on an individual basis. It remains to be seen whether the technology can be made reliable enough to not only benefit high-risk individuals but also the general population.     

Evaluation of combined spinal-epidural anesthesia using two different techniques

There is growing evidence, that Borna Disease virus (BDV) or a variant may cause neuropsychiatric disorders in humans. The presence of specific BDV serum antibodies indicates an earlier contact with BDV. Earlier MRI results showing a raised prevalence of white matter lesions in BDV-seropositive psychiatric patients, possibly indicating encephalitic lesions, are not confirmed in this extended study, however in BDV-seropositive psychiatric patients the occurrence of cerebral atrophy seems to be more frequent, a finding compatible with hydrocephalus e vacuo found in animals after BDV-encephalitis. Because encephalitic lesions in BD are predominantly found in the gray matter of the brain, which is hardly visualized by MRI, the failure to detect lesions in BDV-seropositive patients could be due to methodological problems.     

Evaluation of two AIDS education programs for impoverished Latina women

This paper evaluates and contrasts the effectiveness of two culturally sensitive AIDS education programs developed by the UCLA AIDS Nursing Network and delivered to 213 impoverished Latina homeless or drug-addicted women in Los Angeles. The Comprehensive Health Seeking and Coping Paradigm guided the program, which was implemented by specially trained Latina nurses and outreach workers. A quasi-experimental design was employed where women were randomized by site into Specialized (N = 82) and Traditional (N = 131) programs. Repeated measures ANOVAS and log-linear models were used to evaluate improvement over a two-week period for women in both groups and to identify interactions with program type. Two-week posttest analyses were also conducted to assess program effectiveness, controlling for baseline values of the measure in question, nonequivalency between groups at baseline, and selected demographic characteristics, including acculturation. Results indicated that women in both AIDS education programs improved significantly in cognitive, behavioral, and psychologic outcomes.     

Evaluation of two commercially available carbon dioxide sampling nasal cannulae

Our study compared two commercially available carbon dioxide sampling nasal cannulae for efficacy of oxygenation and relationship of end-tidal carbon dioxide (PETCO2) to arterial carbon dioxide (PaCO2). The two-prong nasal cannula (2PNC) has one prong dedicated to delivering O2 via one naris and the second prong dedicated to sampling exhaled gases via the other naris. The four-prong nasal cannula (4PNC) delivers O2 via a prong in each naris, and samples exhaled gases via another set of prongs in each naris. Forty six patients were divided into three groups, which received either 2 (n = 15), 3 (n = 16), or 4 (n = 15) L/min O2, respectively, and were studied sequentially with standard nasal cannula (SNC), the 2PNC, and then the 4PNC. At each O2 flow rate, PaO2 was equivalent regardless of whether the SNC, 2PNC, or 4PNC was used. Seventy-four percent (34/46) of the 2PNC and 0% (0/46) of the 4PNC PETCO2 values were within +/- 4 torr of the PaCO2 value. The authors conclude that the 2PNC and 4PNC are equally effective compared with an SNC in oxygenating patients, but the PETCO2 measured by the 2PNC provides a superior quantitative estimate of the PaCO2 than that obtained by the 4PNC.     

Evaluation of 7,000+ patients with two different routes of cardioplegia

BACKGROUND: This study examined the efficacy and safety of retrograde cardioplegia in comparison with an antegrade/retrograde approach. METHODS: Between January 1, 1991, and December 31, 1995, 7,032 coronary artery bypass procedures, alone or in combination with valve replacement/repair, were performed using either retrograde cardioplegia (R) or an antegrade/retrograde (AR) approach. There were 4,224 patients in the R group and 2,808 in the AR group. These included elective, urgent, emergent/salvage, first operative, and redo cases. RESULTS: All preoperative, intraoperative, and postoperative variables listed in The Society of Thoracic Surgeons National Cardiac Surgery Database were used to compare the two groups using univariate analysis. The pump time was longer in the AR group, with fewer grafts per patient. The R group had higher predicted risk (3.2% versus 3.0%; p = 0.04), more postoperative atrial fibrillation (34% versus 31%; p = 0.006), and longer postoperative length of stay (8.8 versus 8.0 days; p < 0.001). Using The Society of Thoracic Surgeons National Cardiac Surgery Database predicted risk group model, a subgroup of 221 coronary artery bypass grafting patients in the retrograde (s-R) and 132 coronary artery bypass grafting patients in the antegrade/retrograde (s-AR) group fell into a greater incidence of predicted mortality group (> or = 10%). The s-R subgroup had more patients in New York Heart Association functional class IV. Univariate analysis revealed higher postoperative atrial fibrillation (51% versus 41%; p = 0.05) and longer postoperative length of stay (12.8 versus 10.8 days; p = 0.03) in the s-R subgroup versus the s-AR subgroup. CONCLUSIONS: The results appear to favor neither approach. Preoperatively, both retrograde groups (R and s-R) had higher preoperative predicted risk, but operative mortality or complications were not significantly increased when compared with the AR and s-AR groups. Retrograde cardioplegia alone was shown to be effective in the R and s-R groups, but atrial fibrillation developed in more patients, which could have contributed to longer length of stay in these groups. Antegrade/retrograde cardioplegia offers good immediate outcome but the delivery method can be cumbersome and confusing during the adjustments of flow clamps for antegrade/retrograde delivery and may contribute to prolonged pump times. From this retrospective, nonrandomized review, it appears that retrograde cardioplegia alone provides as good myocardial protection and safety as an antegrade/retrograde approach in either the low-risk or high-risk patient.     

Film-forming polymer-granulated excipients as the matrix materials for controlled release dosage forms

Propyl-4-yn-valproic acid (2-propyl-4-pentynoic acid), an analogue of valproic acid with a triple bond in one alkyl side chain, potently induces exencephaly in mice. Given that propyl-4-yn-valproic acid is a branched chain carboxylic acid, we synthesized a series of analogues with n-alkyl side chains of increasing length and correlated their potential to induce neural tube defects and to inhibit proliferation and induce differentiation in cells of neural origin, the latter being crucial to the orderly structuring of the embryo. All analogues significantly increased the incidence of neural tube defects in the embryos of dams exposed to a single dose of 1.25 mmol/kg on day 8 of gestation. This effect occurred in a dose-dependent manner and the rate of exencephaly increased with the progressive increase in n-alkyl side chain length. Moreover, increasing chain length resulted in a dose-dependent inhibition of C6 glioma proliferation rate over a concentration range of 0-3 mM and this was independent of the cell type employed and mode of estimating proliferative rate. The antiproliferative action of these analogues was associated with profound shape change in neuro-2A neuroblastoma involving extensive neuritogenesis and an associated increase in neural cell adhesion molecule (NCAM) prevalence at points of cell-cell contact, the latter exhibiting a dose-dependent increase when the n-alkyl chain was extended to five carbon units. These results suggest an interaction with a specific site in which the n-alkyl side is proposed to serve as an 'anchor' within a hydrophobic pocket to facilitate the ionic and/or H-bonding of the carboxylic acid and high electron density of the carbon-carbon triple bond.     

Effect of excipients on the stability and structure of lyophilized recombinant human growth hormone

We have investigated the effect of mannitol, sorbitol, methyl alpha-D-mannopyranoside, lactose, trehalose, and cellobiose on the stability and structure of the pharmaceutical protein recombinant human growth hormone (rhGH) in the lyophilized state. All excipients afforded significant protection of the protein against aggregation, particularly at levels to potentially satisfy water-binding sites on the protein in the dried state (i.e., 131:1 excipient-to-protein molar ratio). At higher excipient-to-protein ratios, X-ray diffraction studies showed that mannitol and sorbitol were prone to crystallization and afforded somewhat less stabilization than at lower ratios where the excipient remained in the amorphous, protein-containing phase. The secondary structure of rhGH was determined using Fourier transform infrared (FTIR) spectroscopy. rhGH exhibited a decrease in alpha-helix and increase in beta-sheet structures upon drying. Addition of excipient stabilized the secondary structure upon lyophilization to a varying extent depending on the formulation. Samples with a significant degree of structural conservation, as indicated by the alpha-helix content, generally exhibited reduced aggregation. In addition, prevention of protein-protein interactions (indicated by reduced beta-sheet formation) also tended to result in lower rates of aggregation. Therefore, in addition to preserving the protein structure, bulk additives that do not crystallize easily and remain amorphous in the solid state can be used to increase protein-protein distance and thus prevent aggregation.     

Evaluation of two school smoking education programmes under normal classroom conditions

OBJECTIVES: To assess the effectiveness of two school based smoking education projects in delaying onset of smoking behaviour and in improving health knowledge, beliefs, and values. DESIGN: Cluster randomised controlled trial of two projects taught under normal classroom conditions. Schools were allocated to one of four groups to receive the family smoking education project (FSE); the smoking and me project (SAM); both projects in sequence (FSE/SAM); or no intervention at all. SETTING: 39 schools in Wales and England matched for size and catchment profile. SUBJECTS: All first year pupils in the schools were included and were assessed on three occasions (4538 before teaching (1988), 3930 immediately after teaching (1989), 3786 at one year follow up (1990)). MAIN OUTCOME MEASURES: Self reported smoking behaviour (backed by saliva sample) and change in relevant health knowledge, beliefs, and values. RESULTS: No consistent significant differences in smoking behaviour, health knowledge, beliefs, or values were found between the four groups. For never smokers at baseline the rate of remaining never smokers in 1990 was 74% (594/804) in the control group, 65% (455/704) in the FSE group, 70% (440/625) in the SAM group, and 69% (549/791) in the FSE/SAM group (chi 2adj = 6.1, df = 3, p = 0.1). Knowledge about effects of smoking rose in all groups from a mean score of 5.4 in 1988 to 6.4 in 1989 and 6.5 in 1990. CONCLUSIONS: More comprehensive interventions than school health education alone will be needed to reduce teenage smoking. Other measures including further restrictions on access to cigarettes and on the promotion of tobacco products need to be considered. Further research will be needed to develop effective school based health education projects, which should be formally field tested under normal conditions before widespread dissemination.