Tine testing in HIV positive patients

BACKGROUND: The incidence of tuberculosis is increased in HIV positive patients. Purified protein derivative (PPD, tuberculin) testing has not been performed routinely on patients infected with HIV in the UK and its usefulness in diagnosing tuberculosis in these patients is unclear. METHODS: 198 HIV positive patients were Tine tested and a CD4+ lymphocyte count and chest radiograph were performed. Of the 179 male patients 164 were homosexual or bisexual, 11 were injecting drug users (IDUs), and four were both homosexual and IDUs. Of 19 women 14 were heterosexual and five were IDUs. Patients assessed their own skin reactions at 72 hours, recording the grade on a card which was returned by post. Patients with a grade 0 reaction were requested to have a second test one month later. RESULTS: Details were available on 168 of the 198 patients. Grade 0 reactions occurred in 89 of the 168 patients, requiring a second Tine test, and 73 completed Tine 2 results were received. Of 57 patients with CD4+ lymphocyte counts below 200/mm3, low grade PPD reactivity was seen in 18 on Tine 1 and nine on Tine 2. No history of BCG immunisation of tuberculosis was found in 33 Tine positive patients. Two patients treated for tuberculosis in the previous six months were PPD positive with CD4+ counts of 60/mm3 and 4/mm3 respectively. CONCLUSIONS: PPD reactivity may be maintained despite a CD4+ count of 100/mm3 or less when there is a history of tuberculosis or BCG immunisation.     

Effects of tamoxifen on the cytology of the uterine cervix in breast cancer patients

Knowledge about the central innervation of the lower urinary tract is limited. The spinal cord and the pontine micturition center have been investigated most thoroughly, whereas high centers have received little attention. Pseudorabies virus (PRV), a self-amplifying and transneuronal tracer was injected into the bladder trigone of 21 Sprague-Dawley rats. The animals were killed after 72, 96, and 120 h. The whole CNS was sectioned and immunostained for PRV. CNS centers directly connected to the bladder include the intermedio lateral cell column, the central autonomic nucleus, and the nucleus intercalatus at the spinal cord levels T12-L2 and L6-S2. The raphe pallidus et magnus, the A5 nor-adrenergic area, the pontine micturition center, the locus coeruleus, the periaquaductal gray, the nucleus para- et periventricularis of the hypothalamus, the red nucleus, the medial preoptic area, and the cortex are supraspinal centers connected to the bladder. Lower urinary tract function is a complex multilevel and multineuronal interaction. It involves facilitation and inhibition at many levels of the CNS.     

Analysis of wear mechanisms in low-friction AlMgB14-TiB2 coatings

Recent developments in coating science and technology offer new opportunities to enhance the energy-efficiency and performance of industrial machinery such as hydraulic fluid pumps and motors. The lubricated friction and wear characteristics of two wear-resistant coatings, diamond-like carbon and a nanocomposite material based on AlMgB₁₄-50 vol.% TiB₂, were compared in pin-on-disk tribotests using Mobil DTE-24™ oil as the lubricant. In each case, the pins were fixed 9.53 mm diameter spheres of AISI 52100 steel, the load was 10 N, and the speed 0.5 m/s in all tests. Average steady-state friction coefficient values of 0.10 and 0.08 were measured for the DLC and nanocomposite, respectively. The coatings and their 52100 steel counterfaces were analyzed after the tests by X-ray photoelectron and Auger spectroscopy for evidence of material transfer or tribo-chemical reactions. The low-friction behavior of the boride nanocomposite coating is due to the formation of lubricative boric acid, B(OH)₃. In contrast, the low-friction behavior of the DLC coating is related to the relatively low dielectric constant of the oil-based lubricant, leading to desorption of surface hydrogen from the coating.     

Seam-Tracking for Friction Stir Welded Lap Joints

This article presents a method for automatic seam-tracking in friction stir welding (FSW) of lap joints. In this method, tracking is accomplished by weaving the FSW tool back-and-forth perpendicular to the direction of travel during welding and monitoring force and torque signals. Research demonstrates the ability of this method to automatically track weld seam positions. Additionally, tensile and S-bend test result comparisons demonstrate that weaving most likely does not reduce weld quality. Finally, benefits of this weave-based method to FSW of lap joints are discussed and methods for incorporating it into existing friction stir welding control algorithms (such as axial load control) are examined.     

Dimethylsulfoniopropionate (DMSP) Increases Survival of Larval Sablefish, <Emphasis Type="Italic">Anoplopoma fimbria</Emphasis>

High concentrations of dimethylsulfoniopropionate (DMSP), a chemical compound released by lysed phytoplankton, may indicate high rates of grazing by zooplankton and may thus be a foraging cue for planktivorous fishes. Previous studies have shown that some planktivorous fishes and birds aggregate or alter locomotory behavior in response to this chemical cue, which is likely adaptive because it helps them locate prey. These behavioral responses have been demonstrated in juveniles and adults, but no studies have tested for effects on larval fish. Larvae suffer from high mortality rates and are vulnerable to starvation. While larvae are generally thought to be visual predators, they actually have poor vision and cryptic prey. Thus, larval fish should benefit from a chemical cue that provides information on prey abundance. We reared larval sablefish, Anoplopoma fimbria, for one week and supplemented feedings with varying concentrations of DMSP to test the hypothesis that DMSP affects larval survival. Ecologically relevant DMSP concentrations increased larval survival by up to 70 %, which has implications for production in aquaculture and recruitment in nature. These results provide a new tool for increasing larval production in aquaculture and also suggest that larvae may use DMSP as an olfactory cue. The release of DMSP may be a previously unappreciated mechanism through which phytoplankton affect larval survival and recruitment.     

Supermicron poly(butyl acrylate)/polystyrene core-shell latexes

Latex particles of up to 2 μm can be made by standard emulsion polymerization methods, but attempts at larger sizes usually results in a crop of smaller particles or coagulation of the latex. In this work, it is shown that use of an oil-soluble initiator (2,2′ azodiisobutyronitrile [AIBN]) provides a means by which large (6 μm diameter) polybutyl acrylate latex particles can be made by sequential core-shell polymerizations. It is suggested that the limited water solubility of AIBN decreases the formation of secondary particles and that the lower ionic strength of the water phase enhances stability of the latex compared to a conventional persulfate initiator. To further minimize formation of secondary particles, long reaction times and progressively larger proportions of seed latex are used in successive reactions. © 1992 John Wiley & Sons, Inc.     

Characterization of linear low density polyethylene by temperature rising elution fractionation and by differential scanning calorimetry

In this article we consider characterization of the branching distribution of LLDPE by analytical TREF and by DSC techniques. Qualitatively, both methods yield parallel information, provided that the DSC samples are prepared at very slow cooling rates. Analytical TREF provides more quantitative information, however, in that the mass fraction of material with different branch levels can be estimated. Full characterization of a polyethylene requires the use of a preparative TREF technique, in which fractions dissolved at preselected temperatures are investigated for branching with high resolution ¹³C NMR and for molecular weight distribution, with high temperature SEC analyses.     

A Comparative Evaluation of the Wear Resistance of Various Tool Materials in Friction Stir Welding of Metal Matrix Composites

Friction stir welding (FSW) is the preferred joining method for metal-matrix composites (MMCs). As a solid-state process, it precludes formation of the intermetallic precipitates responsible for degradation of mechanical properties in fusion welds of MMCs. The major barrier to FSW of MMCs is the rapid and severe wear of the welding pin tool, a consequence of prolonged contact between the tool and the harder reinforcements which give the material its enhanced strength. This study evaluates the effectiveness of harder tool materials to combat wear in the FSW of MMCs. The tool materials considered are O1 steel, cemented carbide (WC-Co) of the micrograin and submicrograin varieties, and WC-Co coated with diamond. The challenges which accompany the application of harder tool materials and diamond coatings in FSW are also discussed. This study represents the first use of diamond-coated tools in FSW and the first comparative evaluation of tool materials for this application.     

Lipid Composition Differences of Periphyton,Crustaceans, and Small Fishes in Response to Eutrophication and Management in the Florida Everglades,USA

Eutrophication of the Florida Everglades, USA, has altered the characteristics of the ecosystem, but management strategies are being implemented to accelerate recovery. In this study, we described lipid compositional similarities and differences between periphyton, fish, and crustaceans, and explored if eutrophication and creation of new open-water sloughs in phosphorus (P)-impacted regions of a Northern Everglades impoundment resulted in changes in periphyton biomass and lipid composition, and the lipid composition of a ubiquitous omnivore, Gambusia holbrooki. Lipid biomarker analysis provided insight into microbial community composition, quality of basal resources, and potential resources utilized by consumers. Periphyton biomass and phospholipid fatty acid (PLFA) composition differed in response to eutrophication, but not between P-impacted control and treatment plots. Shifts in relative abundances of lipids indicative of diatoms and green algae mirrored known taxonomic shifts due to eutrophication. For fauna, PLFA were a small and relatively distinct component of the overall total lipid make-up, and profiles were similar between control and treatment plots. However, the PLFA profile of G. holbrooki differed between oligotrophic and eutrophic regions. Fish and crustacean lipids contained significantly greater relative abundances of polyunsaturated fatty acids than were found in periphyton, and profiles differed between fish and crustaceans, suggesting organisms were selectively accumulating or elongating and desaturating lipids de novo, to meet physiological needs. This study builds on findings of microbial responses to eutrophication and recent observations that consumer PLFA profiles can also shift with P-enrichment.     

Diabetes and proteolysis: Effects on carnitine palmitoyltransferase-I and malonyl-CoA binding

Malonyl-CoA binding and malonyl-CoA inhibition of carnitine palmitoyltransferase-1 (CPT-I) were measured in hepatic mitochondria from normal and diabetic rats and in protease-treated mitochondria from fed rats to test the hypothesis that proteolysis represents a mechanism by which diabetes produces changes in the sensitivity of CPT-I to inhibition by malonyl-CoA. As in diabetes, protease treatment increased the apparent K_i values for malonyl-CoA. Palmitoyl-CoA greatly diminished malonyl-CoA specific binding in the mitochondrial system being studied, suggesting strong competition at the malonyl-CoA binding site. Proteolysis decreased capacity for specific binding of malonyl-CoA by 60–80%, but it had no effect on binding affinity. In contrast, the decreased specific binding of malonyl-CoA seen in the diabetic state is accompanied by increased binding affinity. Furthermore, observed K_d values differed from K_i values by a factor of 10 or more, suggesting that measured K_d and K_i may represent different ligand-protein complexes. These data suggest that alterations in inhibition of CPT-I by malonyl-CoA occurring in the diabetic state may involve mechanisms other than simple proteolytic removal of malonyl-CoA binding sites.