788 research outputs found
Заболевания щитовидной железы. Диффузный токсический зоб
ЗОБ ДИФФУЗНЫЙ ТОКСИЧЕСКИЙЩИТОВИДНОЙ ЖЕЛЕЗЫ БОЛЕЗН
Advances in research on the use of biochar in soil for remediation: a review
Purpose: Soil contamination mainly from human activities remains a major environmental problem in the contemporary world. Significant work has been undertaken to position biochar as a readily-available material useful for the management of contaminants in various environmental media notably soil. Here, we review the increasing research on the use of biochar in soil for the remediation of some organic and inorganic contaminants. Materials and methods: Bibliometric analysis was carried out within the past 10 years to determine the increasing trend in research related to biochar in soil for contaminant remediation. Five exemplar contaminants were reviewed in both laboratory and field-based studies. These included two inorganic (i.e., As and Pb) and three organic classes (i.e., sulfamethoxazole, atrazine, and PAHs). The contaminants were selected based on bibliometric data and as representatives of their various contaminant classes. For example, As and Pb are potentially toxic elements (anionic and cationic, respectively), while sulfamethoxazole, atrazine, and PAHs represent antibiotics, herbicides, and hydrocarbons, respectively. Results and discussion: The interaction between biochar and contaminants in soil is largely driven by biochar precursor material and pyrolysis temperature as well as some characteristics of the contaminants such as octanol-water partition coefficient (KOW) and polarity. The structural and chemical characteristics of biochar in turn determine the major sorption mechanisms and define biochar’s suitability for contaminant sorption. Based on the reviewed literature, a soil treatment plan is suggested to guide the application of biochar in various soil types (paddy soils, brownfield, and mine soils) at different pH levels (4–5.5) and contaminant concentrations ( 50 mg kg−1). Conclusions: Research on biochar has grown over the years with significant focus on its properties, and how these affect biochar’s ability to immobilize organic and inorganic contaminants in soil. Few of these studies have been field-based. More studies with greater focus on field-based soil remediation are therefore required to fully understand the behavior of biochar under natural circumstances. Other recommendations are made aimed at stimulating future research in areas where significant knowledge gaps exist
Global, regional, and national incidence, prevalence, and mortality of HIV, 1980–2017, and forecasts to 2030, for 195 countries and territories: a systematic analysis for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017
Background
Understanding the patterns of HIV/AIDS epidemics is crucial to tracking and monitoring the progress of prevention and control efforts in countries. We provide a comprehensive assessment of the levels and trends of HIV/AIDS incidence, prevalence, mortality, and coverage of antiretroviral therapy (ART) for 1980–2017 and forecast these estimates to 2030 for 195 countries and territories.
Methods
We determined a modelling strategy for each country on the basis of the availability and quality of data. For countries and territories with data from population-based seroprevalence surveys or antenatal care clinics, we estimated prevalence and incidence using an open-source version of the Estimation and Projection Package—a natural history model originally developed by the UNAIDS Reference Group on Estimates, Modelling, and Projections. For countries with cause-specific vital registration data, we corrected data for garbage coding (ie, deaths coded to an intermediate, immediate, or poorly defined cause) and HIV misclassification. We developed a process of cohort incidence bias adjustment to use information on survival and deaths recorded in vital registration to back-calculate HIV incidence. For countries without any representative data on HIV, we produced incidence estimates by pulling information from observed bias in the geographical region. We used a re-coded version of the Spectrum model (a cohort component model that uses rates of disease progression and HIV mortality on and off ART) to produce age-sex-specific incidence, prevalence, and mortality, and treatment coverage results for all countries, and forecast these measures to 2030 using Spectrum with inputs that were extended on the basis of past trends in treatment scale-up and new infections.
Findings
Global HIV mortality peaked in 2006 with 1·95 million deaths (95% uncertainty interval 1·87–2·04) and has since decreased to 0·95 million deaths (0·91–1·01) in 2017. New cases of HIV globally peaked in 1999 (3·16 million, 2·79–3·67) and since then have gradually decreased to 1·94 million (1·63–2·29) in 2017. These trends, along with ART scale-up, have globally resulted in increased prevalence, with 36·8 million (34·8–39·2) people living with HIV in 2017. Prevalence of HIV was highest in southern sub-Saharan Africa in 2017, and countries in the region had ART coverage ranging from 65·7% in Lesotho to 85·7% in eSwatini. Our forecasts showed that 54 countries will meet the UNAIDS target of 81% ART coverage by 2020 and 12 countries are on track to meet 90% ART coverage by 2030. Forecasted results estimate that few countries will meet the UNAIDS 2020 and 2030 mortality and incidence targets.
Interpretation
Despite progress in reducing HIV-related mortality over the past decade, slow decreases in incidence, combined with the current context of stagnated funding for related interventions, mean that many countries are not on track to reach the 2020 and 2030 global targets for reduction in incidence and mortality. With a growing population of people living with HIV, it will continue to be a major threat to public health for years to come. The pace of progress needs to be hastened by continuing to expand access to ART and increasing investments in proven HIV prevention initiatives that can be scaled up to have population-level impact
A study of the Z production cross-section in pp collisions at √s = 7 using tau final states
A measurement of the inclusive Z → ττ cross-section in pp collisions at
√s =7 is presented based on a dataset of 1.0 fb[superscript −1] collected by the LHCb detector. Candidates for Z → τ τ decays are identified through reconstructed final states with two muons, a muon and an electron, a muon and a hadron, or an electron and a hadron. The production cross-section for Z bosons, with invariant mass between 60 and 120 GeV/c[superscript 2], which decay to τ leptons with transverse momenta greater than 20 GeV/c and pseudorapidities between 2.0 and 4.5, is measured to be σ[subscript pp]→Z→ττ = 71.4 ± 3.5 ± 2.8 ± 2.5 pb; the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the integrated luminosity. The ratio of the cross-sections for Z → τ τ to Z → μμ is determined to be 0.93 ± 0.09, where the uncertainty is the combination of statistical, systematic, and luminosity uncertainties of the two measurements.National Science Foundation (U.S.
Precision measurement of the B0s-B¯0s oscillation frequency with the decay B0s → D−sπ+
A key ingredient to searches for physics beyond the Standard Model in B0s mixing phenomena is the measurement of the B0s– oscillation frequency, which is equivalent to the mass difference Δms of the B0s mass eigenstates. Using the world's largest B0s meson sample accumulated in a dataset, corresponding to an integrated luminosity of 1.0 fb−1, collected by the LHCb experiment at the CERN LHC in 2011, a measurement of Δms is presented. A total of about 34 000 B0s → D−sπ+ signal decays are reconstructed, with an average decay time resolution of 44 fs. The oscillation frequency is measured to be Δms = 17.768 ± 0.023 (stat) ± 0.006 (syst) ps−1, which is the most precise measurement to date
Chemical treatment enhances skipping of a mutated exon in the dystrophin gene
Duchenne muscular dystrophy (DMD) is a fatal muscle wasting disease caused by a loss of the dystrophin protein. Control of dystrophin mRNA splicing to convert severe DMD to a milder phenotype is attracting much attention. Here we report a dystrophinopathy patient who has a point mutation in exon 31 of the dystrophin gene. Although the mutation generates a stop codon, a small amount of internally deleted, but functional, dystrophin protein is produced in the patient cells. An analysis of the mRNA reveals that the mutation promotes exon skipping and restores the open reading frame of dystrophin. Presumably, the mutation disrupts an exonic splicing enhancer and creates an exonic splicing silencer. Therefore, we searched for small chemicals that enhance exon skipping, and found that TG003 promotes the skipping of exon 31 in the endogenous dystrophin gene in a dose-dependent manner and increases the production of the dystrophin protein in the patient's cells
Low incidence of limb-girdle muscular dystrophy type 2C revealed by a mutation study in Japanese patients clinically diagnosed with DMD
<p>Abstract</p> <p>Background</p> <p>Limb-girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive muscle dystrophy that resembles Duchenne muscular dystrophy (DMD). Although DMD is known to affect one in every 3500 males regardless of race, a widespread founder mutation causing LGMD2C has been described in North Africa. However, the incidence of LGMD2C in Japanese has been unknown because the genetic background remains uncharacterized in many patients clinically diagnosed with DMD.</p> <p>Methods</p> <p>We enrolled 324 patients referred to the Kobe University Hospital with suspected DMD. Mutations in the dystrophin or the SGCG genes were analyzed using not only genomic DNA but also cDNA.</p> <p>Results</p> <p>In 322 of the 324 patients, responsible mutations in the dystrophin were successfully revealed, confirming DMD diagnosis. The remaining two patients had normal dystrophin expression but absence of γ-sarcoglycan in skeletal muscle. Mutation analysis of the SGCG gene revealed homozygous deletion of exon 6 in one patient, while the other had a novel single nucleotide insertion in exon 7 in one allele and deletion of exon 6 in the other allele. These mutations created a stop codon that led to a γ-sarcoglycan deficiency, and we therefore diagnosed these two patients as having LGMD2C. Thus, the relative incidence of LGMD2C among Japanese DMD-like patients can be calculated as 1 in 161 patients suspected to have DMD (2 of 324 patients = 0.6%). Taking into consideration the DMD incidence for the overall population (1/3,500 males), the incidence of LGMD2C can be estimated as 1 per 560,000 or 1.8 per million.</p> <p>Conclusions</p> <p>To the best of our knowledge, this is the first study to demonstrate a low incidence of LGMD2C in the Japanese population.</p
Two novel missense mutations in the myostatin gene identified in Japanese patients with Duchenne muscular dystrophy
BACKGROUND: Myostatin is a negative regulator of skeletal muscle growth. Truncating mutations in the myostatin gene have been reported to result in gross muscle hypertrophy. Duchenne muscular dystrophy (DMD), the most common lethal muscle wasting disease, is a result of an absence of muscle dystrophin. Although this disorder causes a rather uniform pattern of muscle wasting, afflicted patients display phenotypic variability. We hypothesized that genetic variation in myostatin is a modifier of the DMD phenotype. METHODS: We analyzed 102 Japanese DMD patients for mutations in the myostatin gene. RESULTS: Two polymorphisms that are commonly observed in Western countries, p.55A>T and p.153K>R, were not observed in these Japanese patients. An uncommon polymorphism of p.164E>K was uncovered in four cases; each patient was found to be heterozygous for this polymorphism, which had the highest frequency of the polymorphism observed in the Japanese patients. Remarkably, two patients were found to be heterozygous for one of two novel missense mutations (p.95D>H and p.156L>I). One DMD patient carrying a novel missense mutation of p.95D>H was not phenotypically different from the non-carriers. The other DMD patient was found to carry both a novel mutation (p.156L>I) and a known polymorphism (p.164E>K) in one allele, although his phenotype was not significantly modified. Any nucleotide change creating a target site for micro RNAs was not disclosed in the 3' untranslated region. CONCLUSION: Our results indicate that heterozygous missense mutations including two novel mutations did not produce an apparent increase in muscle strength in Japanese DMD cases, even in a patient carrying two missense mutations
Mismatch Repair–Independent Increase in Spontaneous Mutagenesis in Yeast Lacking Non-Essential Subunits of DNA Polymerase ε
Yeast DNA polymerase ε (Pol ε) is a highly accurate and processive enzyme that participates in nuclear DNA replication of the leading strand template. In addition to a large subunit (Pol2) harboring the polymerase and proofreading exonuclease active sites, Pol ε also has one essential subunit (Dpb2) and two smaller, non-essential subunits (Dpb3 and Dpb4) whose functions are not fully understood. To probe the functions of Dpb3 and Dpb4, here we investigate the consequences of their absence on the biochemical properties of Pol ε in vitro and on genome stability in vivo. The fidelity of DNA synthesis in vitro by purified Pol2/Dpb2, i.e. lacking Dpb3 and Dpb4, is comparable to the four-subunit Pol ε holoenzyme. Nonetheless, deletion of DPB3 and DPB4 elevates spontaneous frameshift and base substitution rates in vivo, to the same extent as the loss of Pol ε proofreading activity in a pol2-4 strain. In contrast to pol2-4, however, the dpb3Δdpb4Δ does not lead to a synergistic increase of mutation rates with defects in DNA mismatch repair. The increased mutation rate in dpb3Δdpb4Δ strains is partly dependent on REV3, as well as the proofreading capacity of Pol δ. Finally, biochemical studies demonstrate that the absence of Dpb3 and Dpb4 destabilizes the interaction between Pol ε and the template DNA during processive DNA synthesis and during processive 3′ to 5′exonucleolytic degradation of DNA. Collectively, these data suggest a model wherein Dpb3 and Dpb4 do not directly influence replication fidelity per se, but rather contribute to normal replication fork progression. In their absence, a defective replisome may more frequently leave gaps on the leading strand that are eventually filled by Pol ζ or Pol δ, in a post-replication process that generates errors not corrected by the DNA mismatch repair system
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