Effect of tinidazole, metronidazole and nitrofurazone on nucleic acid synthesis in Clostridium bifermentans

Coplanar lines of different orientations rotating in depth and viewed in parallel projection may appear to rotate in different directions and reverse independently of each other, or they may appear coplanar and all reverse together. The frequency of the latter "grouped" appearance for lines with an orientation range of 30 degrees was a function of the number of lines in a given space. Grouping was greater for lines converging to an implicit vanishing point and for lines with collinear edges regardless of their orientations. Line length, and by inference, interline separation also had effect of the nature of the response.     

Bandwidth requirements for accurate detection of direct path in multipath environment

The accurate detection of the direct path in a dense multipath environment is critical in time-based and angle-of-arrival-based location estimation techniques. It is generally assumed that an infinitely large bandwidth is helpful in the accurate detection of the direct path and high-range resolution. It is experimentally demonstrated that, for a wideband system, a bandwidth of up to 4 GHz, centred on 12.5 GHz, is sufficient for accurate detection of direct path in a typical indoor scattering environment. Additionally, the bandwidth gain, incremental range accuracy with bandwidth, is an effective indicator of the bandwidth requirements for accurate detection of the direct path.     

Experiments and simulations of short-pulse laser-pumped extreme ultraviolet lasers

Recent experimental work on the development of extreme ultraviolet lasers undertaken using as the pumping source the VULCAN laser at the Rutherford Appleton Laboratory is compared to detailed simulations. It is shown that short duration (/spl sim/picosecond) pumping can produce X-ray laser pulses of a few picosecond duration and that measurement of the emission from the plasma can give an estimate of the duration of the gain coefficient. The Ehybrid fluid and atomic physics code developed at the University of York is used to simulate X-ray laser gain and plasma emission. Two postprocessors to the Ehybrid code are utilized: 1) to raytrace the X-ray laser beam amplification and refraction and 2) to calculate the radiation emission in the kiloelectronvolt photon energy range. The raytracing and spectral simulations are compared, respectively, to measured X-ray laser output and the output of two diagnostics recording transverse X-ray emission. The pumping laser energy absorbed in the plasma is examined by comparing the simulations to experimental results. It is shown that at high pumping irradiance (>10/sup 15/ Wcm/sup -2/), fast electrons are produced by parametric processes in the preformed long scalelength plasmas. These fast electrons do not pump the population inversion and so pumping efficiency is reduced at high irradiance.     

Optical deflection measurement for characterization of microelectromechanical systems (MEMS)

Nonintrusive measurement of small out-of-plane motions of microscale structures is critical to the development of microelectromechanical systems (MEMS). This paper presents a low-cost deflection measurement system for MEMS structures based on a fiber optic displacement sensor. The system is demonstrated in the characterization of a microwave switch. The deflection system had a demonstrated sensitivity of 290/spl plusmn/32 /spl mu/V/nm over a deflection range of 100 /spl mu/m. The calibration and linearity of the system are described, and the static and dynamic performance is compared to more elaborate systems.     

Alzheimer paired helical filaments (PHFs) studied by high-resolution TEM: what can vertical Pt-C replication tell us about the organization of the pronase-digested PHF core?

Untreated paired helical filaments (PHFs) and pronase-digested PHF-core filaments were stereoscopically imaged with a freeze-drying vertical platinum-carbon replication preparation method for TEM. The untreated PHF have an average wide region (W) = 22.8 +/- 2.4 nm, a narrow region (T) = 10.6 +/- 1.7 nm, and a helical turn period (L) = 78.6 +/- 13.4. The surfaces of the untreated PHF's fuzzy coat appears disorganized. The widths of the pronase-treated PHF-core filaments were significantly reduced (W(d) = 14.8 +/- 1.2 nm, T(d) = 5.7 +/- 1.0 nm, and L(d) = 75.4 +/- 17 nm). The surfaces of the untreated PHF contained approximately 1.1 nm strands, the same size as tau monomer ( approximately 1.0 nm). The pronase-digested PHF cores mostly contained approximately 1.6 +/- 0.3 nm strands although strand diameters ranged from 0.6-2.5 nm. The strands sometimes appear to be wrapped around the filament axis; less often, they appear to be roughly parallel to the PHF axis, and otherwise appear to be randomly oriented. Images of pronase-digested PHF core images are discussed in relation to the core's biochemical composition, its proposed beta structure, and structural subunit models. Images of the untreated and the pronase-digested PHF support a helical ribbon morphology.     

Covalent functionalization of zinc oxide nanowires for high sensitivity p-nitrophenol detection in biological systems

High-quality zinc oxide (ZnO) nanowires were synthesized using the atmospheric chemical vapor deposition technique and were appropriately characterized. Subsequently, the nanowire surface was covalently grafted with 1-pyrenebutyric acid (PBA) fluorophore, and surface-sensitive X-ray photoelectron spectroscopy and Fourier transform infrared-attenuated total reflectance spectroscopy were utilized to confirm the functionalization of 1-pyrenebutyric acid on the nanowire surface. Additionally, photoluminescence (PL) measurements were used to evaluate the optical behavior of pristine nanowires. Through fluorescence quenching of 1-pyrenebutyric acid by p-nitrophenol, a detection limit of 28 ppb was estimated. Based on these findings, ZnO nanowires functionalized with 1-pyrenebutyric acid are envisaged as extremely sensitive platforms for the ultra-trace detection of p-nitrophenol in biological systems.     

High precision in-cylinder gas thermometry using Laser Induced Gratings: Quantitative measurement of evaporative cooling with gasoline/alcohol blends in a GDI optical engine

The first application of Laser Induced Thermal Gratings Spectroscopy (LITGS) for precision thermometry in a firing GDI optical engine is reported. Crank-angle resolved temperature values were derived from LITGS signals generated in fuel vapour with a pressure dependent precision in the range 0.1–1.0% allowing differences in evaporative or charge cooling effects arising from a variety of ethanol and methanol blends with a model gasoline fuel to be quantified. In addition, fluctuations in temperature arising from cyclic variations in compression were directly detected and measured.     

Collaboration barriers in BIM-based construction networks: A conceptual model

Building information modelling (BIM) teams, hereafter referred to as BIM-based construction networks, are teams whose possibly geographically dispersed members from various organisations and disciplines, perform project tasks on BIM-enabled projects. In recent years, BIM-based construction networks have progressively become the norm in executing BIM activities on projects. However, even though achieving BIM's full capabilities relies on effective collaboration among the team members in BIM-based construction networks, it is still a struggle for these members to collaborate. Nonetheless, only a few studies have been conducted to identify the barriers to strengthening team collaboration in BIM-based construction networks. To address this gap, the current study, by examining 73 journal articles on collaboration in BIM-based construction networks, builds upon a theoretical review of the literature. A conceptual model is presented to capture the main barriers to collaboration in BIM-based construction networks. The study benefits researchers as well as project managers. For researchers, the conceptual model provides an intermediate theory, namely, a theoretical basis to direct further knowledge creation attempts on the topic. In addition, the conceptual model supports project managers on BIM-enabled projects. That is, it simplifies the knowledge now available for practical applications enabling it to be translated into guidelines and practical instructions on real-life projects.     

Stress among South African construction professionals: a job demand-control-support survey

Research into workplace stress in the construction industry has been dominated by studies undertaken in Hong Kong, England and Australia, with relatively little attention having been paid to African countries. A purposively selected sample of thirty-six construction professionals (comprising architects, project managers, construction managers, engineers and quantity surveyors) based in Cape Town, South Africa, were surveyed regarding their perceptions about, and experiences of, workplace stress. The purpose was to identify and rank job demand, job control and job support factors and to analyse these by gender and professional grouping, both in terms of how respondents perceived them, as well as in terms of how frequently they had experienced them. The main finding was that respondents’ perceptions about the importance of job demand, job control and job support factors were largely consistent with their own experience of these factors. Distinguishing between perceptions and experience of stressors and moderators of stress was, however, considered valuable because the fact that differences were found indicates the need for precision in the design of scales. The highest ranked factors were, respectively, ‘critical time constraints’, ‘volume of work’ and ‘adequate compensation (salary)’. Women and men ranked items differently, as did the various professional groups. The main conclusions were that the construction project environment is a time-pressured, complex, environment in which work-life balance is negatively affected, particularly for women. Control over the type, flow and volume of work were perceived to be the main moderators of stress, whilst salary and career path opportunities were perceived to be the main job support moderators of stress. The applicability of using the job demand–control–support framework was confirmed given that the main stressors, control and support moderators were found to be to be largely consistent with the findings of previous studies. Future research taking a gendered approach should anticipate issues important to female respondents and should consider the benefits of qualitative methods. The design of research focusing on construction professionals should consider using the project team as the unit of analysis to ensure that the influence of the interconnectedness of participants’ roles is taken into account.     

Condom use by South African construction workers

Consistent and proper condom use is pivotal in preventing HIV infection. HIV prevalence in South Africa is among the highest in the world, with the construction industry especially affected, yet little is known about condom use by construction workers and the determinants thereof. Data were gathered from 512 site-based workers in the Western Cape. A theoretical model explaining condom use as a function of demographic factors, HIV knowledge, substance usage and risky sexual behaviour (excluding condom use) was proposed and tested using regression and structural equations modelling. The findings indicated that age, gender and level of education were indirect determinants of condom use, with higher levels of education predicting better AIDS-related knowledge. Higher levels of risky sexual behaviour were associated with more frequent use of condoms, suggesting greater awareness of risk. Condom use was adversely affected by greater alcohol and drug use, probably as a result of diminished capacity to assess risk. Finally, lower and not higher levels of AIDS-related knowledge were associated with better condom use, suggesting that improved knowledge of HIV transmission may work contrary to safe sex practice if it lulls the person into a false sense of confidence. Recommendations for targeted workplace interventions are proposed.