816 research outputs found

    Methyl Jasmonate and 1-Aminocyclopropane-1-Carboxylic Acid Interact to Promote Grape Berry Abscission

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    Producción CientíficaThe application of methyl jasmonate (MeJA) or ethephon, an ethylene-releasing agent, to Thompson Seedless grapes can reduce fruit detachment force (FDF) and promote the development of dry stem scars on berries, possibly improving the quality of machine-harvested grapes. However, the amount of MeJA or ethephon needed to stimulate abscission may be prohibitively expensive and result in excessive residues. Thus, experiments were conducted to determine whether MeJA might interact with 1-aminocyclopropane-1-carboxylic acid (ACC), a natural biochemical precursor of ethylene, to promote abscission-related processes and possibly reduce the amount of MeJA needed. In a preliminary trial, MeJA (672 and 1,344 mg/L) interacted with ACC (500 and 1,000 mg/L) to reduce FDF by 25 to 70% compared with untreated grapes. However, MeJA and ACC did not interact to affect preharvest fruit drop, although treatment with 672 or 1,344 mg/L MeJA caused 16 to 23% drop by 3 days after treatment (DAT). In a second trial, grapes treated with MeJA, singly, or with ACC, produced ethylene which peaked at 1 DAT, remained elevated at 2 DAT, and declined rapidly thereafter, whereas grapes treated only with ACC maintained moderately elevated ethylene production throughout the 10-day study. Treatment with ACC or MeJA reduced FDF within 1 or 2 DAT, respectively. By 2 DAT, berries began to abscise from MeJA-treated clusters, regardless of whether they were also treated with ACC, but on 3, 4, and 10 DAT, ACC and MeJA interacted to greatly promote preharvest fruit drop. Moreover, the combination of ACC and MeJA also promoted dry stem scar development. Thus, coapplication of MeJA and ACC is more effective at stimulating grape abscission-related processes than either compound applied singly

    Effects of hydrogen on the morphology and electrical properties of GaN grown by plasma-assisted molecular-beam epitaxy

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    We study the effect of introducing hydrogen gas through the rf-plasma source during plasma-assisted molecular-beam epitaxy of GaN(0001). The well-known smooth-to-rough transition that occurs for this surface as a function of decreasing Ga flux in the absence of H is found to persist even with H present, although the critical Ga flux for this transition increases. Under Ga-rich conditions, the presence of hydrogen is found to induce step bunching (facetting) on the surface. Conductive atomic force microscopy reveals that leakage current through dislocation cores is significantly reduced when hydrogen is present during the growth

    The Enhanced Liver Fibrosis test maintains its diagnostic and prognostic performance in alcohol-related liver disease: a cohort study

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    BACKGROUND: Alcohol is the main cause of chronic liver disease. The Enhanced Liver Fibrosis (ELF) test is a serological biomarker for fibrosis staging in chronic liver disease, however its utility in alcohol-related liver disease warrants further validation. We assessed the diagnostic and prognostic performance of ELF in alcohol-related liver disease. METHODS: Observational cohort study assessing paired ELF and histology from 786 tertiary care patients with chronic liver disease due to alcohol (n = 81) and non-alcohol aetiologies (n = 705). Prognostic data were available for 64 alcohol patients for a median of 6.4 years. Multiple ELF cut-offs were assessed to determine diagnostic utility in moderate fibrosis and cirrhosis. Survival data were assessed to determine the ability of ELF to predict liver related events and all-cause mortality. RESULTS: ELF identified cirrhosis and moderate fibrosis in alcohol-related liver disease independently of aminotransferase levels with areas under receiver operating characteristic curves of 0.895 (95% CI 0.823-0.968) and 0.923 (95% CI 0.866-0.981) respectively, which were non-inferior to non-alcohol aetiologies. The overall performance of ELF was assessed using the Obuchowski method: in alcohol = 0.934 (95% CI 0.908-0.960); non-alcohol = 0.907 (95% CI 0.895-0.919). Using ELF < 9.8 to exclude and ≧ 10.5 to diagnose cirrhosis, 87.7% of alcohol cases could have avoided biopsy, with sensitivity of 91% and specificity of 85%. A one-unit increase in ELF was associated with a 2.6 (95% CI 1.55-4.31, p < 0.001) fold greater odds of cirrhosis at baseline and 2.0-fold greater risk of a liver related event within 6 years (95% CI 1.39-2.99, p < 0.001). CONCLUSIONS: ELF accurately stages liver fibrosis independently of transaminase elevations as a marker of inflammation and has superior prognostic performance to biopsy in alcohol-related liver disease

    Factors associated with severity of hepatic fibrosis in people with chronic hepatitis C infection

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    The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.OBJECTIVE: To determine factors associated with hepatic fibrosis development in people with chronic hepatitis C virus (HCV) infection. METHODS: As a requirement for access to interferon therapy through the S100 scheme in Australia, individual pretreatment demographic and clinical information was collected on 2986 patients from 61 hospital-based liver clinics from 1 October 1994 through 31 December 1996. Patients with both a hepatic fibrosis score and an estimated duration of HCV infection (910) were divided into 540 with no or minimal hepatic fibrosis (stage 0–1) and 370 with moderate to severe hepatic fibrosis (stage 2–3). Seven factors were examined: age at HCV infection, sex, ethnicity, source of infection, duration of infection, alcohol intake, and mean ALT level. A further analysis was performed for all 1135 patients with a hepatic fibrosis score disregarding age at and duration of HCV infection. RESULTS: In multivariate analysis, four factors were significantly associated with moderate to severe hepatic fibrosis: age at infection (OR, 2.33 for age 31–40 years, 5.27 for age > 40 years, and 0.20 for age 30 years, compared with 3 times, compared with 1.5–2 times the upper limit of normal). In the analysis disregarding age at HCV infection and duration of HCV infection, older age was strongly associated with moderate to severe hepatic fibrosis (OR, 2.32 for age 36–40 years, 2.46 for age 41–50 years, 7.87 for age 51–60 years, and 7.15 for age > 60 years, compared with 16–30 years). There was no association in either analysis with sex or source of HCV infection. CONCLUSION: These factors may assist in targeting patients for both liver biopsy-based investigation and therapeutic intervention.Mark Danta, Gregory J Dore, Lisa Hennessy, Yueming Li, Chris R Vickers, Hugh Harley, Meng Ngu, William Reed, Paul V Desmond, William Sievert, Geoff C Farrell, John M Kaldor and Robert G Bate

    Targeted metabolomics reveals proline as a major osmolyte in the chemolithoautotroph Sulfurimonas denitrificans

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    © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in MicrobiologyOpen 7 (2018): e00586, doi:10.1002/mbo3.586.Chemoautotrophic bacteria belonging to the genus Sulfurimonas in the class Campylobacteria are widespread in many marine environments characterized by redox interfaces, yet little is known about their physiological adaptations to different environmental conditions. Here, we used liquid chromatography coupled with tandem mass spectrometry (LC-MS/ MS) in a targeted metabolomics approach to study the adaptations of Sulfurimonas denitrificans to varying salt concentrations that are found in its natural habitat of tidal mudflats. Proline was identified as one of the most abundant internal metabolites and its concentration showed a strong positive correlation with ionic strength, suggesting that it acts as an important osmolyte in S. denitrificans. 2,3-dihydroxypropane- 1- sulfonate was also positively correlated with ionic strength, indicating it might play a previously unrecognized role in osmoregulation. Furthermore, the detection of metabolites from the reductive tricarboxylic acid cycle at high internal concentrations reinforces the importance of this pathway for carbon fixation in Campylobacteria and as a hub for biosynthesis. As the first report of metabolomic data for an campylobacterial chemolithoautotroph, this study provides data that will be useful to understand the adaptations of Campylobacteria to their natural habitat at redox interfaces.NSF, Grant/Award Number: OCE- 1136727 and OCE-1154320; Woods Hole Oceanographic Institution; U.S. Geological Surve

    Global analysis of polarized DIS & SIDIS data with improved small-xx helicity evolution

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    We analyze the world polarized deep-inelastic scattering (DIS) and semi-inclusive DIS (SIDIS) data at low values of x<0.1x < 0.1, using small-xx evolution equations for the flavor singlet and nonsinglet helicity parton distribution functions (hPDFs). The hPDFs for quarks, antiquarks, and gluons are extracted and evolved to lower values of xx to make predictions for the future Electron-Ion Collider (EIC). We improve on our earlier work by employing the more realistic large-Nc&NfN_c\, \& N_f limit of the revised small-xx helicity evolution, and incorporating running coupling corrections along with SIDIS data into the fit. We find an anti-correlation between the signs of the gluon and CC-even quark hPDFs as well as the g1g_1 structure function. While the existing low-xx polarized DIS and SIDIS data are insufficient to constrain the initial conditions for the polarized dipole amplitudes in the helicity evolution equations, future EIC data will allow more precise predictions for hPDFs and the g1g_1 structure function for xx values beyond those probed at the EIC. Using the obtained hPDFs, we discuss the contributions to the proton spin from quark and gluon spins at small xx.Comment: 42 Pages, 21 Figures

    The accident insurance as a promising direction for insurance in Russia

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    Статья посвящена анализу состояния рынка услуг страхования от несчастных случаев. Актуальность исследования определяется тем, что страхование является неотъемлемым атрибутом цивилизованного общества, позволяющим сохранить обеспеченность доходами при неблагоприятных ситуациях. По статистике в России уровень травматизма и непредвиденных обстоятельств весьма велик. Люди традиционно уделяют мало внимания формированию резервов на случай временной или постоянной нетрудоспособности. Цель работы: рассмотреть систему страхования от несчастных случаев. Методы исследования: метод сопоставления, необходимый для выявления главных тенденций на рынке страховых услуг; аналитический метод, позволяющий понять, какие проблемы характерны для этого вида страхования; статистический метод, выявляющий масштабы страхования от несчастных случаев. Результаты: раскрывается сущность и виды страхования от несчастных случаев.The article is devoted to analysis of service market of accident insurance. The relevant of the study is determined by the fact that insurance is an integral attribute of a civilized society that allows you to save security income in adverse situations. According to statistics, in Russia the level of injury and unforeseen circumstances is very great. People traditionally pay little attention to formation of reserves in case of temporary or permanent incapacity for work. The main aim of the study is to consider the system of the accident insurance. Methods: the matching method required to identify the main trends in the insurance market; the analytical technique which allows understanding the typical problems for this type of insurance; the statistical method allows us to identify the extent of accident insurance. Results. The paper reveals the essence and types of accident insurance and considers the model events when the insurance company indemnifies for the damage. The causes of the demand for this type of insurance in Russia are identified. Based on the statistical data the author has determined the proportion of the accident insured people

    Transcriptomic analysis of field-droughted sorghum from seedling to maturity reveals biotic and metabolic responses.

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    Drought is the most important environmental stress limiting crop yields. The C4 cereal sorghum [Sorghum bicolor (L.) Moench] is a critical food, forage, and emerging bioenergy crop that is notably drought-tolerant. We conducted a large-scale field experiment, imposing preflowering and postflowering drought stress on 2 genotypes of sorghum across a tightly resolved time series, from plant emergence to postanthesis, resulting in a dataset of nearly 400 transcriptomes. We observed a fast and global transcriptomic response in leaf and root tissues with clear temporal patterns, including modulation of well-known drought pathways. We also identified genotypic differences in core photosynthesis and reactive oxygen species scavenging pathways, highlighting possible mechanisms of drought tolerance and of the delayed senescence, characteristic of the stay-green phenotype. Finally, we discovered a large-scale depletion in the expression of genes critical to arbuscular mycorrhizal (AM) symbiosis, with a corresponding drop in AM fungal mass in the plants' roots

    A biophysical model of prokaryotic diversity in geothermal hot springs

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    Recent field investigations of photosynthetic bacteria living in geothermal hot spring environments have revealed surprisingly complex ecosystems, with an unexpected level of genetic diversity. One case of particular interest involves the distribution along hot spring thermal gradients of genetically distinct bacterial strains that differ in their preferred temperatures for reproduction and photosynthesis. In such systems, a single variable, temperature, defines the relevant environmental variation. In spite of this, each region along the thermal gradient exhibits multiple strains of photosynthetic bacteria adapted to several distinct thermal optima, rather than the expected single thermal strain adapted to the local environmental temperature. Here we analyze microbiology data from several ecological studies to show that the thermal distribution field data exhibit several universal features independent of location and specific bacterial strain. These include the distribution of optimal temperatures of different thermal strains and the functional dependence of the net population density on temperature. Further, we present a simple population dynamics model of these systems that is highly constrained by biophysical data and by physical features of the environment. This model can explain in detail the observed diversity of different strains of the photosynthetic bacteria. It also reproduces the observed thermal population distributions, as well as certain features of population dynamics observed in laboratory studies of the same organisms
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