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Background and purpose: Chemistry examinations can favour the deployment of algorithmic procedures like Le Chatelier's Principle (LCP) rather than reasoning using chemical principles. This study investigated the explanatory resources which high school students use to answer equilibrium problems and whether the marks given for examination answers require students to use approaches beyond direct application of LCP. Sample: The questionnaire was administered to 162 students studying their first year of advanced chemistry (age 16/17) in three high achieving London high schools. Design and methods: The students' explanations of reversible chemical systems were inductively coded to identify the explanatory approaches used and interviews with 13 students were used to check for consistency. AS level examination questions on reversible reactions were analysed to identify the types of explanations sought and the students' performance in these examinations was compared to questionnaire answers. Results: 19% of students used a "holistic" explanatory approach: when the rates of forward and reverse reactions are correctly described, recognising their simultaneous and mutually dependent nature. 36% used a "mirrored reactions" approach when the connected nature of the forward and reverse reactions is identified, but not their mutual dependency. 42% failed to recognize the interdependence of forward and reverse reactions ("reactions not connected" approach). Only 4% of marks for AS examination questions on reversible chemical systems asked for responses which went beyond either direct application of LCP or recall of equilibrium knowledge. 37% of students attained an A grade in their AS national examinations. Conclusions: Examinations favour the application of LCP making it possible to obtain the highest grade with little understanding of reversible chemical systems beyond a direct application of this algorithm. Therefore students' understanding may be attenuated so that they are unable to use kinetic sub-micro level ideas which will support the building of deeper energetic conceptions at university. (Contains 7 tables, 5 figures and 1 note.)

Objective Gestational diabetes ( GDM) is characterized by maternal glucose intolerance that manifests during pregnancy. Because GDM resembles type 2 diabetes (T2 DM), shared genetic predisposition is likely but has not been established. We tested the hypothesis that a genetic risk score ( GRS) that included variants known to be associated with T2 DM is associated with GDM. Study design We conducted a case-control study using the Vanderbilt Medical Center biobank (Bio VU) and calculated a simple-count GRS using 34 variants previously associated with T2 DM or fasting glucose in the general population, or with GDM or glucose intolerance in pregnancy. We assessed the association of the GRS with GDM adjusting for maternal age, parity, and body mass index ( BMI) and calculated the area under the curve for the receiver-operating characteristic curve (c-statistic). Study population Among Caucasian women, we identified 458 cases of GDM and 1538 pregnant controls with normal glucose tolerance. Results Cases of GDM had a higher number of risk alleles compared to controls (38.9±4.0 vs 37.4±4.0 risk alleles, P=1.6×10−11). The GRS was significantly associated with GDM; the adjusted odds ratio associated with each additional risk allele was 1.10 (95% CI: 1.07-1.13, P=6×10−11). Clinical variables predicted the risk of GDM (c-statistic 0.67, 95% CI: 0.64-0.70), and adding the GRS modestly improved prediction (0.70, 95% CI: 0.67-0.73). Conclusions Among Caucasian women, a GRS that included common T2 DM genetic risk variants was associated with increased risk of GDM but showed limited utility in the identification of GDM cases. [ABSTRACT FROM AUTHOR]

Purpose: Programmed death-1 (PD-1) ligation downregulates active lymphocyte responses. The authors tested whether PD-1 or its ligands are expressed in the posterior segment during active intraocular inflammation.Methods: Experimental autoimmune uveitis (EAU) was induced using interphotoreceptor retinoid-binding protein (IRBP 161-180). Ocular inflammation was evaluated by histology and expression of PD-1 ligand tested by immunohistochemistry. PD-1 expression was evaluated by immunohistochemistry, RT-PCR, and Western immunoblotting.Results: Using immunohistochemistry, PD-1, but not its ligands, was constitutively expressed in retinal neurons of naive mouse retina. Both PD-1 and its ligands were observed, as expected, in sites of active inflammation.Conclusions: PD-1 and its ligands were expressed in sites of active inflammation, in accordance with many other models of inflammatory disease. Surprisingly, PD-1, not previously described outside the immune system, was constitutively expressed in retinal neurons, raising the possibility that PD-1 signaling may be important for neuronal function in the absence of an inflammatory insult. [ABSTRACT FROM AUTHOR]

Abstract: Background:: A clindamycin phosphate 2% single-dose vaginal cream (CSDVC) formulation has been designed to provide release of clindamycin equivalent to 7 daily doses of a conventional clindamycin phosphate 2% vaginal cream (CVC). Objective:: The purpose of this study was to comparethe systemic bioavailability of clindamycin from 1 dose of CSDVC with that from 1 dose from a 7-day regimen of CVC in healthy women. Methods:: This was a single-center, open-label, randomized, 2-period, 2-sequence crossover study that enrolled healthy, nonpregnant, adult women. Subjects were randomly assigned to receive a single 5-g intravaginal dose of CSDVC or CVC. Blood samples were then collected for 96 hours after study medication administration. Subjects were crossed over after a 14-day washout period, and received a single dose of the other medication. Blood samples were then collected for 96 hours after administration of the second drug. The plasma clindamycin pharmacokinetic profiles were determined, using a validated assay with a lower limit of detection of 0.2 ng/mL, and compared between treatments. Results:: The median age of women was 43.5 years(range, 18–66 years), the median weight was 65.0 kg (range, 47.7–91.8 kg), and the median body mass index was 25.4 kg/m2 (range, 19.2–34.7 kg/m2). AUC from time 0 to the last detectable concentration (AUCO0−t) and from time 0 to infinity (AUCO0−∞) and Cmax were significantly lower with CSDVC than with CVC (geometric means of 98.61 vs 794.21 ng · h/mL for AUCO0−t, 100.33 vs 809.14 ng · h/mL for AUC0−∞, and 3.18 vs 42.27 ng/mL for Cmax; all comparisons, P < 0.001 between formulations). Overall bioavailability of clindamycin from CSDVC was ∼12% of that from CVC, as measured by AUC. The arithmetic mean Tmax was significantly longer with CSDVC (26.4 vs 9.8 hours; P < 0.007). There were 18 adverse events reported during this study. The most common adverse event with each formulation was headache (CSDVC, 10%; CVC, 25%). Conclusions:: Systemic bioavailability of clindamycinwas significantly lower and systemic absorption was significantly slower with the CSDVC formulation than with the single dose of 7-day CVC formulation in these healthy volunteers. [Copyright &y& Elsevier]

The issue of access to cheap and healthy food for those living in poverty is now part of the social and health agenda in the United Kingdom. The pilot study described in this paper is investigating access to healthy food in a deprived area of London. The study has three interrelated elements: the local community, the school as part of the community and geographical mapping. The paper focuses on the work that has been undertaken with primary schools in the study area, identifying the strategies being used to collect data and outlining some preliminary findings. [ABSTRACT FROM AUTHOR]

Breath holding was used as the basis of a simple test of respiratory chemosensitivity. Breath holding was begun at selected degrees of hypercapnia produced by CO2 rebreathing. In 16 healthy control subjects there was a linear regression of the log of breath-holding time on the PCO2 at the start of breath holding. Breath-holding time (BHT) and the slope of a log BHT/Pco2 plot were closely correlated with the ventilatory response to CO2. In five cases of the idiopathic hypoventilation syndrome, CO2 retention and reduced ventilatory response to CO2 were accompanied by prolonged breath-holding time and the regression of log BHT on Pco2 was abnormally flat. However, in 17 patients with chronic airways obstruction, breath-holding time was never prolonged and the log BHT/Pco2 relationship was normal, even though 13 had a diminished ventilatory response to CO2 and four had chronic CO2 retention. It is concluded that the BHT/Pco2 relationship provides a useful index of respiratory chemosensitivity which is not influenced by airways obstruction. This may be helpful in the detection of impaired chemosensitivity as a cause of CO2 retention even when the ventilation CO2 response is reduced non-specifically by coexisting airways obstruction. [ABSTRACT FROM PUBLISHER]

Deals with the importance of checking the blood levels of patients receiving drug treatment. Difficulty of interpreting blood level data; Limits to look for in blood levels.

The atelectatic retraction pocket (ARP) has been implicated in the development of chronic otitis media and cholesteatoma. The ARP's tendency for persistence or recurrence despite treatment is a significant otologic problem. The purpose of this study is to define and discuss this clinical entity and the use of cartilage-perichondrium tympanoplasty as a safe and predictable method of treatment, reducing destructive complications while maintaining ear function. A retrospective analysis of 85 operated ears is presented. [ABSTRACT FROM AUTHOR]

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Electricity energy savings potential by eliminating air leakage from ducts in large commercial buildings is on the order of 10 kWh/m2 per year (1 kWh/ft2). We have tested, in two large commercial buildings, a new technology that simultaneously seals duct leaks and measures effective leakage area of ducts. The technology is based upon injecting a fog of aerosolized sealant particles into a pressurized duct system. In brief, this process involves blocking all of the intentional openings in a duct system (e.g. diffusers). Therefore, when the system is pressurized, the only place for the air carrying the aerosol particles to exit the system is through the leaks. The key to the technology is to keep the particles suspended within the airstream until they reach the leaks, and then to have them leave the airstream and deposit on the leak sites. The principal finding from this field study was that the aerosol technology is capable of sealing the leaks in a large commercial building duct system within a reasonable time frame. In the first building, 66% of the leakage area was sealed within 2.5 h of injection, and in the second building 86% of the leakage area was sealed within 5 h. We also found that the aerosol could be blown through the VAV boxes in the second building without impacting their calibrations or performance. Some remaining questions are: (1) how to achieve sealing rates comparable to those experienced in smaller residential systems; and (2) what tightness level these ducts systems can be brought to by means of aerosol sealing. [Copyright &y& Elsevier]