424 research outputs found

    Vanadium

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    International audienceVanadium (chemical symbol, V) is a d-block transition metal,silver in color, appearing in the first long period of the peri-odic table between titanium and chromium. Vanadium hastwo stable isotopes: 50V and 51V, with atomic abundance of0.25 % and 99.75 %, respectively. Vanadium has several oxidation forms (between 2+ and 5+). In the lithosphere, Voccurs as reducing V(III) form, whereas in oxidizing con- ditions V prevails under V(IV) form. Vanadium(II) is partic- ularly unstable in the environment. Vanadium(III) is more stable than V(II), but it is also gradually oxidized by the air or dissolved oxygen. Vanadium(V) is expected to be the prevailing form in waters exposed to atmospheric oxygen, whereas V(IV) may be present in reducing environments. Depending upon geometry and environment, V ionic radii vary between 36 pm and 79 pm. Vanadium has a high melting point of 1910 42 C and is a mildly incompatible, refractory,lithophile (siderophile in the iron core and chondrites) ele- ment. Vanadium has an electronegativity of 1.63 on the Pau- ling scale and displays a first ionization potential of 6.74 eV. More details can be found in Richards (2006) and Haynes (2015)

    Therapeutic DNA vaccine induces broad T cell responses in the gut and sustained protection from viral rebound and AIDS in SIV-infected rhesus macaques.

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    Immunotherapies that induce durable immune control of chronic HIV infection may eliminate the need for life-long dependence on drugs. We investigated a DNA vaccine formulated with a novel genetic adjuvant that stimulates immune responses in the blood and gut for the ability to improve therapy in rhesus macaques chronically infected with SIV. Using the SIV-macaque model for AIDS, we show that epidermal co-delivery of plasmids expressing SIV Gag, RT, Nef and Env, and the mucosal adjuvant, heat-labile E. coli enterotoxin (LT), during antiretroviral therapy (ART) induced a substantial 2-4-log fold reduction in mean virus burden in both the gut and blood when compared to unvaccinated controls and provided durable protection from viral rebound and disease progression after the drug was discontinued. This effect was associated with significant increases in IFN-γ T cell responses in both the blood and gut and SIV-specific CD8+ T cells with dual TNF-α and cytolytic effector functions in the blood. Importantly, a broader specificity in the T cell response seen in the gut, but not the blood, significantly correlated with a reduction in virus production in mucosal tissues and a lower virus burden in plasma. We conclude that immunizing with vaccines that induce immune responses in mucosal gut tissue could reduce residual viral reservoirs during drug therapy and improve long-term treatment of HIV infection in humans

    Morphometry of the Cranial Base in Subjects with Class III Malocclusion

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    The significance of the cranial base in the development of Class III malocclusion remains uncertain. The purpose of this study was to determine whether the form of the cranial base differs between prepubertal Class I and Class III subjects. Lateral cephalographs of 73 children of European-American descent aged between 5 and 11 years with Class III malocclusion were compared with those of their counterparts with a normal, Class I molar occlusion. The cephalographs were traced, checked, and subdivided into seven age- and sex-matched groups. Average geometries, scaled to an equivalent size, were generated based on 13 craniofacial landmarks by means of Procrustes analysis, and these configurations were statistically tested for equivalence. Bivariate and multivariate analyses utilizing 5 linear and angular measurements were undertaken to corroborate the Procrustes analysis. Graphical analysis, utilizing thin-plate spline and finite element methods, was performed for localization of differences in cranial base morphology. Results indicated that cranial base morphology differed statistically for all age-wise comparisons. Graphical analysis revealed that the greatest differences in morphology occurred in the posterior cranial base region, which generally consisted of horizontal compression, vertical expansion, and size contraction. The sphenoidal region displayed expansion, while the anterior regions showed shearing and local increases in size. It is concluded that the shape of the cranial base differs in subjects with Class III malocclusion compared with the normal Class I configuration, due in part to deficient orthocephalization, or failure of the cranial base to flatten during development.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67377/2/10.1177_00220345970760021101.pd

    Quality of intervention delivery in a cluster randomised controlled trial : a qualitative observational study with lessons for implementation fidelity

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    Abstract Background Understanding intervention fidelity is an essential part of the evaluation of complex interventions because fidelity not only affects the validity of trial findings, but also because studies of fidelity can be used to identify barriers and facilitators to successful implementation, and so provide important information about factors likely to impact the uptake of the intervention into clinical practice. Participant observation methods have been identified as being particularly valuable in studies of fidelity, yet are rarely used. This study aimed to use these methods to explore the quality of implementation of a complex intervention (Safewards) on mental health wards during a cluster randomised controlled trial. Specific aims were firstly to describe the different ways in which the intervention was implemented, and secondly to explore the contextual factors moderating the quality of intervention delivery, in order to inform ‘real world’ implementation of the intervention. Methods Safewards was implemented on 16 mental health wards in England. We used Research Assistants (RAs) trained in participant observation to record qualitative observational data on the quality of intervention delivery (n = 565 observations). At the end of the trial, two focus groups were conducted with RAs, which were used to develop the coding framework. Data were analysed using thematic analysis. Results There was substantial variation in intervention delivery between wards. We observed modifications to the intervention which were both fidelity consistent and inconsistent, and could enhance or dilute the intervention effects. We used these data to develop a typology which describes the different ways in which the intervention was delivered. This typology could be used as a tool to collect qualitative observational data about fidelity during trials. Moderators of Safewards implementation included systemic, interpersonal, and individual factors and patient responses to the intervention. Conclusions Our study demonstrates how, with appropriate training in participant observation, RAs can collect high-quality observational data about the quality of intervention delivery during a trial, giving a more complete picture of ‘fidelity’ than measurements of adherence alone. Trial registration ISRCTN registry; IRSCTN38001825 . Registered 29 August 201

    Envelope Determinants of Equine Lentiviral Vaccine Protection

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    Lentiviral envelope (Env) antigenic variation and associated immune evasion present major obstacles to vaccine development. The concept that Env is a critical determinant for vaccine efficacy is well accepted, however defined correlates of protection associated with Env variation have yet to be determined. We reported an attenuated equine infectious anemia virus (EIAV) vaccine study that directly examined the effect of lentiviral Env sequence variation on vaccine efficacy. The study identified a significant, inverse, linear correlation between vaccine efficacy and increasing divergence of the challenge virus Env gp90 protein compared to the vaccine virus gp90. The report demonstrated approximately 100% protection of immunized ponies from disease after challenge by virus with a homologous gp90 (EV0), and roughly 40% protection against challenge by virus (EV13) with a gp90 13% divergent from the vaccine strain. In the current study we examine whether the protection observed when challenging with the EV0 strain could be conferred to animals via chimeric challenge viruses between the EV0 and EV13 strains, allowing for mapping of protection to specific Env sequences. Viruses containing the EV13 proviral backbone and selected domains of the EV0 gp90 were constructed and in vitro and in vivo infectivity examined. Vaccine efficacy studies indicated that homology between the vaccine strain gp90 and the N-terminus of the challenge strain gp90 was capable of inducing immunity that resulted in significantly lower levels of post-challenge virus and significantly delayed the onset of disease. However, a homologous N-terminal region alone inserted in the EV13 backbone could not impart the 100% protection observed with the EV0 strain. Data presented here denote the complicated and potentially contradictory relationship between in vitro virulence and in vivo pathogenicity. The study highlights the importance of structural conformation for immunogens and emphasizes the need for antibody binding, not neutralizing, assays that correlate with vaccine protection. © 2013 Craigo et al

    Improving adherence to glaucoma medication: a randomised controlled trial of a patient-centred intervention (The Norwich Adherence Glaucoma Study)

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    Background Improving adherence to ocular hypertension (OH)/glaucoma therapy is highly likely to prevent or reduce progression of optic nerve damage. The present study used a behaviour change counselling intervention to determine whether education and support was beneficial and cost-effective in improving adherence with glaucoma therapy. Methods A randomised controlled trial with a 13-month recruitment and 8-month follow-up period was conducted. Patients with OH/glaucoma attending a glaucoma clinic and starting treatment with travoprost were approached. Participants were randomised into two groups and adherence was measured over 8 months, using an electronic monitoring device (Travalert® dosing aid, TDA). The control group received standard clinical care, and the intervention group received a novel glaucoma education and motivational support package using behaviour change counselling. Cost-effectiveness framework analysis was used to estimate any potential cost benefit of improving adherence. Results Two hundred and eight patients were recruited (102 intervention, 106 control). No significant difference in mean adherence over the monitoring period was identified with 77.2% (CI, 73.0, 81.4) for the control group and 74.8% (CI, 69.7, 79.9) for the intervention group (p = 0.47). Similarly, there was no significant difference in percentage intraocular pressure reduction; 27.6% (CI, 23.5, 31.7) for the control group and 25.3% (CI, 21.06, 29.54) for the intervention group (p = 0.45). Participants in the intervention group were more satisfied with information about glaucoma medication with a mean score of 14.47/17 (CI, 13.85, 15.0) compared with control group which was 8.51 (CI, 7.72, 9.30). The mean intervention cost per patient was GB£10.35 (<US$16) and not cost-effective. Conclusions Adherence with travoprost was high and not further increased by the intervention. Nevertheless, the study demonstrated that provision of information, tailored to the individual, was inexpensive and able to achieve high patient satisfaction with respect to information about glaucoma medication. Measurement of adherence remains problematic since awareness of study participation may cause a change in participant behaviour

    Treatment adherence with the easypod™ growth hormone electronic auto-injector and patient acceptance: survey results from 824 children and their parents

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    <p>Abstract</p> <p>Background</p> <p>Accurately monitoring adherence to treatment with recombinant human growth hormone (r-hGH) enables appropriate intervention in cases of poor adherence. The electronic r-hGH auto-injector, easypod™, automatically records the patient's adherence to treatment. This study evaluated adherence to treatment of children who started using the auto-injector and assessed opinions about the device.</p> <p>Methods</p> <p>A multicentre, multinational, observational 3-month survey in which children received r-hGH as part of their normal care. Physicians reviewed the recorded dose history and children (with or without parental assistance) completed a questionnaire-based survey. Children missing ≤2 injections per month (92% of injections given) were considered adherent to treatment. Adherence was compared between GH treatment-naïve and treatment-experienced children.</p> <p>Results</p> <p>Of 834 recruited participants, 824 were evaluated. The median (range) age was 11 (1-18) years. From the recorded dose history, 87.5% of children were adherent to treatment over the 3-month period. Recorded adherence was higher in treatment-naïve (89.7%, n = 445/496) than in treatment-experienced children (81.7%, n = 152/186) [Fisher's exact test FI(X) = 7.577; <it>p </it>= 0.0062]. According to self-reported data, 90.2% (607/673) of children were adherent over 3 months; 51.5% (421/817) missed ≥1 injection over this period (mainly due to forgetfulness). Concordance between reported and recorded adherence was 84.3%, with a trend towards self-reported adherence being higher than recorded adherence. Most children liked the auto-injector: over 80% gave the top two responses from five options for ease of use (720/779), speed (684/805) and comfort (716/804). Although 38.5% (300/780) of children reported pain on injection, over half of children (210/363) considered the pain to be less or much less than expected. Given the choice, 91.8% (732/797) of children/parents would continue using the device.</p> <p>Conclusions</p> <p>easypod™ provides an accurate method of monitoring adherence to treatment with r-hGH. In children who received treatment with r-hGH using easypod™, short-term adherence is good, and significantly higher in treatment-naïve children compared with experienced children. Children/parents rate the device highly. The high level of acceptability of the device is reflected by a desire to continue using it by over 90% of the children in the survey.</p

    Retained Surgical Items and Minimally Invasive Surgery

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    A retained surgical item is a surgical patient safety problem. Early reports have focused on the epidemiology of retained-item cases and the identification of patient risk factors for retention. We now know that retention has very little to do with patient characteristics and everything to do with operating room culture. It is a perception that minimally invasive procedures are safer with regard to the risk of retention. Minimally invasive surgery is still an operation where an incision is made and surgical tools are placed inside of patients, so these cases are not immune to the problem of inadvertent retention. Retained surgical items occur because of problems with multi-stakeholder operating room practices and problems in communication. The prevention of retained surgical items will therefore require practice change, knowledge, and shared information between all perioperative personnel

    An Assessment of the Impact of Hafting on Paleoindian Point Variability

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    It has long been argued that the form of North American Paleoindian points was affected by hafting. According to this hypothesis, hafting constrained point bases such that they are less variable than point blades. The results of several studies have been claimed to be consistent with this hypothesis. However, there are reasons to be skeptical of these results. None of the studies employed statistical tests, and all of them focused on points recovered from kill and camp sites, which makes it difficult to be certain that the differences in variability are the result of hafting rather than a consequence of resharpening. Here, we report a study in which we tested the predictions of the hafting hypothesis by statistically comparing the variability of different parts of Clovis points. We controlled for the potentially confounding effects of resharpening by analyzing largely unused points from caches as well as points from kill and camp sites. The results of our analyses were not consistent with the predictions of the hypothesis. We found that several blade characters and point thickness were no more variable than the base characters. Our results indicate that the hafting hypothesis does not hold for Clovis points and indicate that there is a need to test its applicability in relation to post-Clovis Paleoindian points
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