94 research outputs found
Electrical conductivity in granular media and Branly's coherer: A simple experiment
accepted for publication in American Journal of Physics (to be published between February 2005 and June 2005)We show how a simple laboratory experiment can illustrate certain electrical transport properties of metallic granular media. At a low critical imposed voltage, a transition from an insulating to a conductive state is observed. This transition comes from an electro-thermal coupling in the vicinity of the microcontacts between grains where microwelding occurs. Our apparatus allows us to obtain an implicit determination of the microcontact temperature, which is analogous to the use of a resistive thermometer. The experiment also illustrates an old problem, the explanation of Branly's coherer effect - a radio wave detector used for the first wireless radio transmission, and based on the sensitivity of the metal fillings conductivity to an electromagnetic wave
Ціноутворення земель техногенного походження як чинник формування рівня їх споживчих властивостей
Визначено засади ціноутворення як головного чинника обгрунтування рівня відтворення екологічної та господарської цінності земель техногенного походження, встановлено вплив грошової оцінки на формування їх цільового споживчого ринку, представлено принципи поєднання екологічних та економічних складових оцінки рекультивованого ґрунту.Определены основы ценообразования как главного фактора обоснования уровня восстановления экологической и хозяйственной ценности земель техногенного происхождения, определено влияние денежной оценки на формирование их целевого потребительского рынка, представлены принципы объединения экологических и экономических составляющих оценки рекультивированного грунта.Defined pricing principles as the main factor of level playing ground environmental and economic values of land anthropogenic origin, the effect of monetary valuation of forming their target consumer market, representing a combination of ecological principles and economic evaluation of reclaimed soil constituents
Isoniazid Preventive Therapy Added to ART to Prevent TB: An Individual Participant Data Meta-Analysis
Background:
Isoniazid preventive therapy prevents active tuberculosis in people with HIV, but previous studies have found no evidence of benefit in people with HIV who had a negative tuberculin skin test, and a non-significant effect on mortality. We aimed to estimate the effect of isoniazid preventive therapy given with antiretroviral therapy (ART) for the prevention of tuberculosis and death among people with HIV across population subgroups.
Methods:
We searched PubMed, Embase, the Cochrane database, and conference abstracts from database inception to Jan 15, 2019, to identify potentially eligible randomised trials. Eligible studies were trials that enrolled HIV-positive adults (age ≥15 years) taking ART who were randomly assigned to either daily isoniazid preventive therapy plus ART or ART alone and followed up longitudinally for outcomes of incident tuberculosis and mortality. We approached all authors of included trials and requested individual participant data: coprimary outcomes were relative risk of incident tuberculosis and all-cause mortality. We did a single-stage meta-analysis of individual participant data using stratified Cox-proportional hazards models. We did prespecified subgroup analyses by sex, CD4 cell count, and evidence of immune sensitisation to tuberculosis (indicated by tuberculin skin test or interferon-γ release assays [IGRAs]). We also assessed the relative risk of liver injury in an additional prespecified analysis. This study is registered with PROSPERO, CRD42019121400.
Findings:
Of 838 records, we included three trials with data for 2611 participants and 8584·8 person-years of follow-up for the outcome of incident tuberculosis, and a subset of 2362 participants with 8631·6 person-years of follow-up for the coprimary outcome of all-cause mortality. Risk for tuberculosis was lower in participants given isoniazid preventive therapy and ART than participants given ART alone (hazard ratio [HR] 0·68, 95% CI 0·49–0·95, p=0·02). Risk of all-cause mortality was lower in participants given isoniazid preventive therapy and ART than participants given ART alone, but this difference was non-significant (HR 0·69, 95% CI 0·43–1·10, p=0·12). Participants with baseline CD4 counts of less than 500 cells per μL had increased risk of tuberculosis, but there was no significant difference in the benefit of isoniazid preventive therapy with ART by sex, baseline CD4 count, or results of tuberculin skin test or IGRAs. 65 (2·5%) of 2611 participants had raised alanine aminotransferase, but data were insufficient to calculate an HR.
Interpretation:
Isoniazid preventive therapy with ART prevents tuberculosis across demographic and HIV-specific and tuberculosis-specific subgroups, which supports efforts to further increase use of isoniazid preventive therapy with ART broadly among people living with HIV.
Funding:
National Institutes of Health and National Institute of Allergy and Infectious Diseases
A Trial of Early Antiretrovirals and Isoniazid Preventive Therapy in Africa
BACKGROUND: In sub-Saharan Africa, the burden of human immunodeficiency virus (HIV)-associated tuberculosis is high. We conducted a trial with a 2-by-2 factorial design to assess the benefits of early antiretroviral therapy (ART), 6-month isoniazid preventive therapy (IPT), or both among HIV-infected adults with high CD4+ cell counts in Ivory Coast. METHODS: We included participants who had HIV type 1 infection and a CD4+ count of less than 800 cells per cubic millimeter and who met no criteria for starting ART according to World Health Organization (WHO) guidelines. Participants were randomly assigned to one of four treatment groups: deferred ART (ART initiation according to WHO criteria), deferred ART plus IPT, early ART (immediate ART initiation), or early ART plus IPT. The primary end point was a composite of diseases included in the case definition of the acquired immunodeficiency syndrome (AIDS), non-AIDS-defining cancer, non-AIDS-defining invasive bacterial disease, or death from any cause at 30 months. We used Cox proportional models to compare outcomes between the deferred-ART and early-ART strategies and between the IPT and no-IPT strategies. RESULTS: A total of 2056 patients (41% with a baseline CD4+ count of ≥500 cells per cubic millimeter) were followed for 4757 patient-years. A total of 204 primary end-point events were observed (3.8 events per 100 person-years; 95% confidence interval [CI], 3.3 to 4.4), including 68 in patients with a baseline CD4+ count of at least 500 cells per cubic millimeter (3.2 events per 100 person-years; 95% CI, 2.4 to 4.0). Tuberculosis and invasive bacterial diseases accounted for 42% and 27% of primary end-point events, respectively. The risk of death or severe HIV-related illness was lower with early ART than with deferred ART (adjusted hazard ratio, 0.56; 95% CI, 0.41 to 0.76; adjusted hazard ratio among patients with a baseline CD4+ count of ≥500 cells per cubic millimeter, 0.56; 95% CI, 0.33 to 0.94) and lower with IPT than with no IPT (adjusted hazard ratio, 0.65; 95% CI, 0.48 to 0.88; adjusted hazard ratio among patients with a baseline CD4+ count of ≥500 cells per cubic millimeter, 0.61; 95% CI, 0.36 to 1.01). The 30-month probability of grade 3 or 4 adverse events did not differ significantly among the strategies. CONCLUSIONS: In this African country, immediate ART and 6 months of IPT independently led to lower rates of severe illness than did deferred ART and no IPT, both overall and among patients with CD4+ counts of at least 500 cells per cubic millimeter. (Funded by the French National Agency for Research on AIDS and Viral Hepatitis; TEMPRANO ANRS 12136 ClinicalTrials.gov number, NCT00495651.)
PLoS One
INTRODUCTION: The Temprano and START trials provided evidence to support early ART initiation recommendations. We projected long-term clinical and economic outcomes of immediate ART initiation in Cote d'Ivoire. METHODS: We used a mathematical model to compare three potential ART initiation criteria: 1) CD4 <350/muL (ART<350/muL); 2) CD4 <500/muL (ART<500/muL); and 3) ART at presentation (Immediate ART). Outcomes from the model included life expectancy, 10-year medical resource use, incremental cost-effectiveness ratios (ICERs) in 90/person-year). We assessed cost-effectiveness relative to Cote d'Ivoire's 2017 per capita annual gross domestic product (680/YLS compared to ART<350/muL, ranging from cost-saving to an ICER of 801.9M to $812.6M compared to ART<350/muL. CONCLUSIONS: In Cote d'Ivoire, immediate compared to later ART initiation will increase life expectancy, decrease HIV transmission, and be cost-effective over the long-term, with modest budget impact. Immediate ART initiation is an appropriate, high-value standard of care in Cote d'Ivoire and similar settings
BMJ Open
INTRODUCTION: Acute malnutrition (AM) is a continuum condition, arbitrarily divided into moderate and severe AM (SAM) categories, funded and managed in separate programmes under different protocols. Optimising acute MAlnutrition (OptiMA) treatment aims to simplify and optimise AM management by treating children with mid-upper arm circumference (MUAC) <125 mm or oedema with one product-ready-to-use therapeutic food-at a gradually tapered dose. Our main objective was to compare the OptiMA strategy with the standard nutritional protocol in children 6-59 months presenting with MUAC <125 mm or oedema without additional complications, as well as in children classified as uncomplicated SAM (ie, MUAC <115 mm or weight-for-height Z-score (WHZ) <-3 or with oedema). METHODS AND ANALYSIS: This study was a non-inferiority, individually randomised controlled clinical trial conducted at community level in the Democratic Republic of Congo. Children 6-59 months presenting with MUAC <125 mm or WHZ <-3 or with bipedal oedema and without medical complication were included after signed informed consent in outpatient health facilities. All participants were followed for 6 months. Success in both arms was defined at 6 months post inclusion as being alive, not acutely malnourished per the definition applied at inclusion and without an additional episode of AM throughout the 6-month observation period. Recovery among children with uncomplicated SAM was the main secondary outcome. For the primary objective, 890 participants were needed, and 480 children with SAM were needed for the main secondary objective. We will perform non-inferiority analyses in per-protocol and intention-to-treat basis for both outcomes. ETHICS AND DISSEMINATION: Ethics approvals were obtained from the National Health Ethics Committee of the Democratic Republic of Congo and from the Ethics Evaluation Committee of Inserm, the French National Institute for Health and Medical Research (Paris, France). We will submit results for publication to a peer-reviewed journal and disseminate findings in international and national conferences and meetings. TRIAL REGISTRATION NUMBER: NCT03751475. Registered 19 September 2018, https://clinicaltrials.gov/ct2/show/NCT03751475
Effect of isoniazid preventive therapy on risk of death in west African, HIV-infected adults with high CD4 cell counts: long-term follow-up of the Temprano ANRS 12136 trial.
BACKGROUND: Temprano ANRS 12136 was a factorial 2 × 2 trial that assessed the benefits of early antiretroviral therapy (ART; ie, in patients who had not reached the CD4 cell count threshold used to recommend starting ART, as per the WHO guidelines that were the standard during the study period) and 6-month isoniazid preventive therapy (IPT) in HIV-infected adults in Côte d'Ivoire. Early ART and IPT were shown to independently reduce the risk of severe morbidity at 30 months. Here, we present the efficacy of IPT in reducing mortality from the long-term follow-up of Temprano. METHODS: For Temprano, participants were randomly assigned to four groups (deferred ART, deferred ART plus IPT, early ART, or early ART plus IPT). Participants who completed the trial follow-up were invited to participate in a post-trial phase. The primary post-trial phase endpoint was death, as analysed by the intention-to-treat principle. We used Cox proportional models to compare all-cause mortality between the IPT and no IPT strategies from inclusion in Temprano to the end of the follow-up period. FINDINGS: Between March 18, 2008, and Jan 5, 2015, 2056 patients (mean baseline CD4 count 477 cells per μL) were followed up for 9404 patient-years (Temprano 4757; post-trial phase 4647). The median follow-up time was 4·9 years (IQR 3·3-5·8). 86 deaths were recorded (Temprano 47 deaths; post-trial phase 39 deaths), of which 34 were in patients randomly assigned IPT (6-year probability 4·1%, 95% CI 2·9-5·7) and 52 were in those randomly assigned no IPT (6·9%, 5·1-9·2). The hazard ratio of death in patients who had IPT compared with those who did not have IPT was 0·63 (95% CI, 0·41 to 0·97) after adjusting for the ART strategy (early vs deferred), and 0·61 (0·39-0·94) after adjustment for the ART strategy, baseline CD4 cell count, and other key characteristics. There was no evidence for statistical interaction between IPT and ART (pinteraction=0·77) or between IPT and time (pinteraction=0·94) on mortality. INTERPRETATION: In Côte d'Ivoire, where the incidence of tuberculosis was last reported as 159 per 100 000 people, 6 months of IPT has a durable protective effect in reducing mortality in HIV-infected people, even in people with high CD4 cell counts and who have started ART. FUNDING: National Research Agency on AIDS and Viral Hepatitis (ANRS)
Incidence of serious morbidity in HIV-infected adults on antiretroviral therapy in a West African care centre, 2003-2008
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