Improvement of chemical vapor deposition process for production of large diameter carbon base monofilaments

Research was conducted to develop large diameter carbon monofilament, containing 25 to 35 mole % element boron, in the 2.0 to 10.0 mil diameter range using the chemical vapor deposition process. The objective of the program was to gain an understanding of the critical process variables and their effect on fiber properties. Synthesis equipment was modified to allow these variables to be studied. Improved control of synthesis variables permitted reduction in scatter of properties of the monofilaments. Monofilaments have been synthesized in the 3.0 to nearly 6.0 mil diameter range having measured values up to 552,000 psi for ultimate tensile strength and up to 30 million psi for elastic modulus

Further development of chemical vapor deposition process for production of large diameter carbon-base monofilaments

The development of large diameter carbon-base monofilament in the 50 micron to 250 micron diameter range using the chemical vapor deposition process is described. The object of this program was to determine the critical process variables which control monofilament strength, monofilament modulus, and monofilament diameter. It was confirmed that wide scatter in the carbon substrate strength is primarily responsible for the scatter in the monofilament strength. It was also shown through etching experiments that defective substrate surface conditions which can induce low strength modular growth in the monofilament layers are best controlled by processing improvements during the synthesis of the substrate. Modulus was found to be linearily proportional to monofilament boron content. Filament modulus was increased to above 27.8MN/sq cm but only by a considerable increase in monofilament boron content to 60 wt. % or more. Monofilament diameter depended upon dwell time in the synthesis apparatus. A monofilament was prepared using these findings which had the combined properties of a mean U.T.S. of 398,000 N/sq cm, a modulus of 18.9 MN/sq cm (24,000,000 psi), and a diameter of 145 microns. Highest measured strength for this fiber was 451,000 N/sq cm (645,000 psi)

Public Interest Immunity: Al Megrahi v HM Advocate

The Lockerbie case has already contributed significantly to the jurisprudence of the law of evidence. Al Megrahi v HM Advocate continues in that vein, shedding some light on how the law relating to public interest immunity now operates following devolution

Eumeces lagunensis

Number of Pages: 3Integrative BiologyGeological Science

Sensitivity of Second Harmonic Generation to Space Charge Effects at Si(111)/Electrolyte and Si(111)/SiO\u3csub\u3e2\u3c/sub\u3e/Electrolyte Interfaces

The potential dependence in the surface second harmonic response from hydrogen terminated n‐Si(111) and oxidized n‐Si(111) surfaces has been examined in aqueous NH4F and H2SO4 solutions. The relative phase of the nonlinear response as measured by rotational anisotropy experiments is found to be highly sensitive to the presence of the oxide and the field applied across the Si(111)/oxide/electrolyte interface. These observations are attributed to field effects within the space–charge region of the semiconductor which vary with the presence and thickness of the insulating oxide layer on the Si(111) surface

Isoniazid resistance in <i>Mycobacterium tuberculosis</i>

Drug resistant tuberculosis (TB) is increasing worldwide and it is now estimated by the World Health Organisation (WHO) that 7% of TB cases globally are resistant to isoniazid (INH). INH is a key drug for the treatment of TB, alongside rifampicin (RIF). Understanding factors which influence the emergence and propagation of INH resistance and the influence of INH resistance on TB treatment success are vital in improving global TB control efforts. Vietnam is ranked 12th of 22 high burden countries for TB and has a high prevalence of INH resistance (25%) with a relatively modest prevalence of TB resistant to both INH and RIF (multi-drug resistant, MDR TB) (2.7%). The first study in this thesis developed rapid screening tests for both RIF and INH resistance in Mycobacterium tuberculosis isolates which showed high accuracy. The specificity and the sensitivity of the MAS-PCR test for INH resistance compared to the conventional phenotypic DST were 100% [95% CI 92.9-100%] and 90% [95% CI 82.4-95.1 %], respectively. The second study demonstrated that the minimum inhibitory concentration (MIC) for INH is influenced by both the mutation responsible for resistance to INH and the lineage backbone of the M.tuberculosis isolate. A two-way ANOVA of MIC including both strain lineage (p=0.003) and resistance mutation (p<0.001) showed highly significant independent effects of both factors on MIC level. MIC to INH of isolates with a katG315 mutation (2ug/ml) was significantly higher compared to MIC to INH of isolates with an inhA-15 mutation (0.25p.g/ml) and wild-type isolates (0- 0.lug/ml) (p<0.00l). The independent effect of the strain lineage on INH MIC was predicted to correspond to a 2.68-fold (95% Cl 1.52-4.73, p<0.001) increase for Beijing lineage strains and a 1.40-fold (95% Cl 0.72-2.74, p=0.32) increase for EuroAmerican lineage strains in comparison with strains of the Indo-Oceanic lineage. The third study investigated the impact of INH resistance on outcome in patients with HIV-associated TB meningitis (HIV/TBM) and showed that HIV/TBM patients infected with INH resistant M.tuberculosis which remains susceptible to RIF have significantly worse outcomes than patients infected with fully susceptible strains. The adjusted hazard ratio for MDR patients in comparison with fully susceptible or streptomycin (STR)-monoresistant isolates was 5.21 [95% Cl 2.38-11.42], p<0.0001 compared with HR= 1.78 [95% Cl 1.18-2.66], p=0.005 for patients with INH resistant isolates (+/-STR resistance). The final study investigated the distribution of N-acetylator-2 (NAT2) phenotypes for INH metabolism in healthy volunteers from the Vietnamese Kinh population and correlated this with phenotypes using caffeine as a surrogate indicator for INH metabolism. This study showed that characterisation of 3 single nucleotide polymorphisms is sufficient to determine the acetylator status of individuals of Vietnamese Kinh ethnicity and that there is a predominance of fast acetylators (65%) in this popUlation. A simple PCR-RFLP test was developed to enable rapid determination of acetylator status for further studies. Collectively, these results contribute to our understanding of INH resistance in M.tuberculosis and provide molecular tools for further studies of this crucial drug

A Delphi Study on Research Priorities for Trauma Nursing

Objectives: To identify and prioritize research questions of importance to trauma patient care and of interest to trauma nurses. Methods: A three-round Delphi technique was used to solicit, identify, and prioritize problems for trauma nursing research. In round 1, experienced trauma nurses (N = 208) generated 513 problems, which were analyzed, categorized, and collapsed into 111 items for subsequent rounds. Round 2 participants rated each research question on a 1 to 7 scale on two criteria: impact on patient welfare and value for practicing nurses. Group median scores provided by 166 round 2 respondents and respondents\u27 individual round 2 scores were indicated on the round 3 questionnaire. Subjects rated the questions again on the same criteria and indicated whether nurses, independently or in collaboration with other health professionals, should assume responsibility for that research. Median and mean scores and rank order were determined for each item. Results: Respondents who completed all three rounds (n = 137) had a mean of 8.3 years of trauma experience. Nine research questions ranked within the top 20 on both criteria. The two research questions that ranked highest on both criteria were: What are the most effective nursing interventions in the prevention of pulmonary and circulatory complications in trauma patients? and What are the most effective methods for preventing aspiration in trauma patients during the postoperative phase? The third-ranked question regarding patient welfare was: What psychological and lifestyle changes result from traumatic injury? Regarding value for practicing nurses, What are the most effective educational methods to prepare and maintain proficiency in trauma care providers? ranked third. Conclusion: These research priorities provide impetus and direction for nursing and collaborative investigation in trauma care

A zeta function approach to the relation between the numbers of symmetry planes and axes of a polytope

A derivation of the Ces\`aro-Fedorov relation from the Selberg trace formula on an orbifolded 2-sphere is elaborated and extended to higher dimensions using the known heat-kernel coefficients for manifolds with piecewise-linear boundaries. Several results are obtained that relate the coefficients, $b_i$, in the Shephard-Todd polynomial to the geometry of the fundamental domain. For the 3-sphere we show that $b_4$ is given by the ratio of the volume of the fundamental tetrahedron to its Schl\"afli reciprocal.Comment: Plain TeX, 26 pages (eqn. (86) corrected