Sexual networks and the transmission of HIV in London

Copyright @ 1998 Cambridge University Press.This paper discusses ways in which empirical research investigating sexual networks can further understanding of the transmission of HIV in London, using information from a 24-month period of participant observation and 53 open-ended, in-depth interviews with eighteen men and one woman who have direct and indirect sexual links with each other. These interviews enabled the identification of a wider sexual network between 154 participants and contacts during the year August 1994-July 1995. The linked network data help to identify pathways of transmission between individuals who are HIV + and those who are HIV -, as well as sexual links between 'older' and 'younger' men, and with male prostitutes. There appears to be considerable on-going transmission of HIV in London. The majority of participants reported having had unprotected anal and/or vaginal sex within a variety of relationships. The implications of these findings for policies designed to prevent the transmission of HIV are discussed.The Wellcome Trust and The Health Education Authority

Correlations in Nuclear Matter

We analyze the nuclear matter correlation properties in terms of the pair correlation function. To this aim we systematically compare the results for the variational method in the Lowest Order Constrained Variational (LOCV) approximation and for the Bruekner-Hartree-Fock (BHF) scheme. A formal link between the Jastrow correlation factor of LOCV and the Defect Function (DF) of BHF is established and it is shown under which conditions and approximations the two approaches are equivalent. From the numerical comparison it turns out that the two correlation functions are quite close, which indicates in particular that the DF is approximately local and momentum independent. The Equations of State (EOS) of Nuclear Matter in the two approaches are also compared. It is found that once the three-body forces (TBF) are introduced the two EOS are fairly close, while the agreement between the correlation functions holds with or without TBF.Comment: 11 figure

San Marco D/L solar array system design and performance

The design and performance of the solar array system for the San Marco D/L spacecraft is described in detail. The solar array system design is shown to be suitable for spacecraft which have elastically sensitized outer surfaces to measure aerodynamic forces. However, the performance of this solar array system is shown to be at least 30 percent less efficient than conventional spacecraft solar array designs. An on-board experiment to compare the in-flight performances of Si and GaAs solar cell panels is also described. Preflight performance data show that at beginning-of-life, air mass zero solar illumination, 28 C and peak power output the Si panels are at last 20 percent less efficient than the GaAs panels

Terminal ruthenium carbido complexes as σ-donor ligands

The terminal carbido ligand of (Pcy_3)_2(Cl)_2RuC coordinates to other metal centers in a σ-donor fashion, as in (Pcy_3)_2(Cl)_2Ru≡C–Pd(Cl)_2(Sme_2) and (Pcy_3)_2(Cl)_2Ru≡C–Mo(CO)_5

Cationic Alkylaluminum-Complexed Zirconocene Hydrides: NMR-Spectroscopic Identification, Crystallographic Structure Determination, and Interconversion with Other Zirconocene Cations

The ansa-zirconocene complex rac-Me_2Si(1-indenyl)_2ZrCl_2 ((SBI)ZrCl_2) reacts with diisobutylaluminum hydride and trityl tetrakis(perfluorophenyl)borate in hydrocarbon solutions to give the cation [(SBI)Zr(μ-H)_3(Al^iBu_2)_2]^+, the identity of which is derived from NMR data and supported by a crystallographic structure determination. Analogous reactions proceed with many other zirconocene dichloride complexes. [(SBI)Zr(μ-H)_3(Al^iBu2)_2]^+ reacts reversibly with ClAl^iBu_2 to give the dichloro-bridged cation [(SBI)Zr(μ-Cl)_2Al^iBu_2]^+. Reaction with AlMe_3 first leads to mixed-alkyl species [(SBI)Zr(μ-H)_3(AlMe_x^iBu_(2−x))_2^]+ by exchange of alkyl groups between aluminum centers. At higher AlMe_3/Zr ratios, [(SBI)Zr(μ-Me)_2AlMe_2]^+, a constituent of methylalumoxane-activated catalyst systems, is formed in an equilibrium, in which the hydride cation [(SBI)Zr(μ-H)_3(AlR_2)_2]^+ strongly predominates at comparable HAl^iBu_2 and AlMe_3 concentrations, thus implicating the presence of this hydride cation in olefin polymerization catalyst systems

Which conformations make stable crystal structures? Mapping crystalline molecular geometries to the conformational energy landscape

The ability to anticipate the shape adopted by flexible molecules in the solid state is crucial for engineering and predicting crystal packing and, hence, properties. In this study, the conformations adopted by flexible molecules in their crystal structures are assessed in terms of their relationship to the calculated global conformational landscape. The study quantifies the limits on molecular strain that can be induced by intermolecular interactions in single-component crystal structures of molecules with no intramolecular hydrogen bonding, demonstrating that some molecules are distorted by up to 20 kJ/mol by crystal packing forces. Furthermore, we find that crystallisation often selects high energy conformers, but only when the high energy conformer is more extended than the lower energy options, allowing for greater intermolecular stabilisation. Based on these observations, we propose that the crystallisability of conformers is assessed in terms of their energies and surface areas. We formulate this as a parameterised pseudo-energy related to molecular surface area, which leads to a dramatic improvement in our ability to predict the conformations adopted by molecules in their crystal structure

Interventions for treating traumatised permanent front teeth: avulsed (knocked out) and replanted (Review)

Background: Traumatic dental injuries are common. One of the most severe injuries is when a permanent tooth is knocked completely out of the mouth (avulsed). In most circumstances the tooth should be replanted as quickly as possible. There is uncertainty on which interventions will maximise the survival and repair of the replanted tooth. This is an update of a Cochrane Review first published in 2010. Objectives: To compare the effects of a range of interventions for managing traumatised permanent front teeth with avulsion injuries. Search methods: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 8 March 2018), Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 2) in the Cochrane Library (searched 8 March 2018), MEDLINE Ovid (1946 to 8 March 2018), and Embase Ovid (1980 to 8 March 2018). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Selection criteria: We considered randomised and quasi‐randomised controlled trials that included a minimum follow‐up period of 12 months, for interventions for avulsed and replanted permanent front teeth. Data collection and analysis: Two review authors independently selected studies, extracted data and assessed the risk of bias. Authors were contacted where further information about their study was required. Main results: Four studies, involving a total of 183 participants and 257 teeth were identified. Each of the interventions aimed to reduce infection or alter the inflammatory response or both at the time of or shortly after the tooth or teeth were replanted. Each study assessed a different intervention and therefore it was not appropriate or possible to numerically synthesise the data. All evidence was rated as being of very low quality due to problems with risk of bias and imprecision of results. This means that we are very uncertain about all of the results presented in this review. One study at high risk of bias with 69 participants (138 teeth) compared a 20‐minute soak with gentamycin sulphate for both groups prior to replantation with the experimental group receiving daily hyperbaric oxygen for 80 minutes for the first 10 days. There was some evidence of a benefit for the hyperbaric oxygen group in respect of periodontal healing, tooth survival, and pulpal healing. One study at unclear risk of bias with 22 participants (27 teeth) compared the use of two root canal medicaments, Ledermix and Ultracal. There was insufficient evidence of a difference for periodontal healing or tooth survival. This was the only study to formally report adverse events with none identified. Study authors reported that Ledermix caused a greater level of patient dissatisfaction with the colour of avulsed and replanted teeth. A third study at high risk of bias with 19 participants compared extra‐ or intra‐oral endodontics for avulsed teeth which were stored dry for longer than 60 minutes before replantation. There was insufficient evidence of a difference in periodontal healing. The fourth study at high risk of bias with 73 participants compared a 10‐minute soak in either thymosin alpha 1 or saline before replantation followed by daily gingival injections with these same medicaments for the first 7 days. There was some evidence of a benefit for thymosin alpha 1 with respect to periodontal healing and tooth survival. Authors' conclusions: Based on the results of the included studies, there is insufficient evidence to support or refute the effectiveness of different interventions for avulsed and replanted permanent front teeth. The overall quality of existing evidence was very low, and therefore great caution should be exercised when generalising the results of the included trials. There is urgent need for further well‐designed randomised controlled trials

Detoxification in rehabilitation in England: effective continuity of care or unhappy bedfellows?

There is evidence that residential detoxification alone does not provide satisfactory treatment outcomes and that outcomes are significantly enhanced when clients completing residential detoxification attend rehabilitation services (Gossop, Marsden, Stewart, & Rolfe, 1999; Ghodse, Reynolds, Baldacchino, et al., 2002). One way of increasing the likelihood of this continuity of treatment is by providing detoxification and rehabilitation within the same treatment facility to prevent drop-out, while the client awaits a rehabilitation bed or in the transition process. However, there is little research evidence available on the facilities that offer both medical detoxification and residential rehabilitation. The current study compares self-reported treatment provision in 87 residential rehabilitation services in England, 34 of whom (39.1%) reported that they offered detoxification services within their treatment programmes. Although there were no differences in self-reported treatment philosophies, residential rehabilitation services that offered detoxification were typically of shorter duration overall, had significantly more beds and reported offering more group work than residential rehabilitation services that did not offer detoxification. Outcomes were also different, with twice as many clients discharged on disciplinary grounds from residential rehabilitation services without detoxification facilities. The paper questions the UK classification of residential drug treatment services as either detoxification or rehabilitation and suggests the need for greater research focus on the aims, processes and outcomes of this group of treatment providers

Electrospray synthesis of PLGA TIPS microspheres

We successfully demonstrate the synthesis of polymer microspheres using a single electrospray source, and show their physical characterisation. Electrospray has proven to be a versatile method to manufacture particles, giving tight control over size with quasi-monodisperse size distributions. It is a liquid atomisation technique that generates a monodisperse population of highly charged liquid droplets over a broad size range (nanometres to tens of microns). The droplets contain liquid precursors for the in-flight synthesis of particles, and control over the trajectory of these droplets can be precisely manipulated with the use of electric fields to drive them to a grounded substrate. This study reports a method to synthesize poly(lactic-co-glycolic) acid (PLGA) microspheres using the electrospray and thermally induced phase separation (TIPS) techniques, followed by subsequent freeze-drying, for particle production. These microspheres are of interest as vehicles for controlled drug release systems