2,622 research outputs found
Hyperosmotic priming of arabidopsis seedlings establishes a long-term somatic memory accompanied by specific changes of the epigenome
<p>Background: In arid and semi-arid environments, drought and soil salinity usually occur at the beginning and end of a plant's life cycle, offering a natural opportunity for the priming of young plants to enhance stress tolerance in mature plants. Chromatin marks, such as histone modifications, provide a potential molecular mechanism for priming plants to environmental stresses, but whether transient exposure of seedlings to hyperosmotic stress leads to chromatin changes that are maintained throughout vegetative growth remains unclear.</p>
<p>Results: We have established an effective protocol for hyperosmotic priming in the model plant Arabidopsis, which includes a transient mild salt treatment of seedlings followed by an extensive period of growth in control conditions. Primed plants are identical to non-primed plants in growth and development, yet they display reduced salt uptake and enhanced drought tolerance after a second stress exposure. ChIP-seq analysis of four histone modifications revealed that the priming treatment altered the epigenomic landscape; the changes were small but they were specific for the treated tissue, varied in number and direction depending on the modification, and preferentially targeted transcription factors. Notably, priming leads to shortening and fractionation of H3K27me3 islands. This effect fades over time, but is still apparent after a ten day growth period in control conditions. Several genes with priming-induced differences in H3K27me3 showed altered transcriptional responsiveness to the second stress treatment.</p>
<p>Conclusion: Experience of transient hyperosmotic stress by young plants is stored in a long-term somatic memory comprising differences of chromatin status, transcriptional responsiveness and whole plant physiology.</p>
clinical presentation and prevalence of spontaneous bacterial peritonitis in patients with cryptogenic cirrhosis and features of metabolic syndrome
BACKGROUND:Nonalcoholic steatohepatitis (NASH) may progress to cirrhosis. The prevalence and clinical relevance that spontaneous bacterial peritonitis may have in complicating ascites due to NASH-related cirrhosis have yet to be defined.METHODS:Among 611 cases of cirrhosis-associated ascites, 45 patients with cryptogenic cirrhosis were retrospectively identified. Of these, 36 patients and a control group of subjects with viral-associated ascites were followed up and compared in a case control study. Information on the onset of ascites, with or without spontaneous bacterial peritonitis, history of risk factors for multimetabolic syndrome, and serological and ascitic laboratory data were compared between groups.RESULTS:Spontaneous bacterial peritonitis occurred significantly more often in patients with cryptogenic cirrhosis than in equally symptomatic viral controls. The prevalence of obesity, diabetes and spontaneous bacterial peritonitis was significantly higher in patients with cryptogenic cirrhosis. Although liver function was similar in both groups, cryptogenic cirrhosis patients had lower aminotransferase levels. Multivariate analysis identified diabetes, juvenile obesity and spontaneous bacterial peritonitis as independent factors associated with ascites due to cryptogenic cirrhosis.CONCLUSIONS:Features suggestive of NASH are more frequently observed in patients with ascites and cryptogenic cirrhosis than in age- and sex-matched ascitic patients with well-defined viral etiology. Ascites may be a presenting symptom of NASH-related cirrhosis, and affected patients have a twofold greater risk of spontaneous bacterial peritonitis
Modelling the mechanical behaviour of metal powder during Die compaction process
In this work, powder compaction process was investigated by using a numerical material model, which involves Mohr-Coulomb theory and an elliptical surface plasticity model. An effective algorithm was developed and implemented in the ANSYS finite element (FEM) code by using the subroutine USERMAT. Some simulations were performed to validate the proposed metal powder material model. The interaction between metal powder and die walls was considered by means of contact elements. In addition to the analysis of metal powder behaviour during compaction, the actions transmitted to die were also investigated, by considering different friction coefficients. This information is particularly useful for a correct die design
Tunneling spectroscopy studies of aluminum oxide tunnel barrier layers
We report scanning tunneling microscopy and ballistic electron emission
microscopy studies of the electronic states of the uncovered and
chemisorbed-oxygen covered surface of AlOx tunnel barrier layers. These states
change when chemisorbed oxygen ions are moved into the oxide by either flood
gun electron bombardment or by thermal annealing. The former, if sufficiently
energetic, results in locally well defined conduction band onsets at ~1 V,
while the latter results in a progressively higher local conduction band onset,
exceeding 2.3 V for 500 and 600 C thermal anneals
The Functional Psychotherapy Approach: A Process-Outcome Multiple Case Study
Objective: The present work aims to conduct the first naturalistic empirical investigation
of the process and outcome assessment of functional psychotherapy (FP) treatment.
The FP model of psychotherapy is rooted in psychoanalysis and integrates the verbal
communication approach founded on transference and countertransference dynamics
with the analysis of bodily processes.
Method: The study sample included ten patients recruited on a voluntary basis and
treated by clinicians in their private practices. Each patient received FP with an average
duration of 40 h (min 35 and max 42). Therapies had weekly sessions, were audiorecorded with the patient’s written consent, and lasted for an average of 10 months
(min 9 and max 12). Outcome and process tools included the Minnesota Multiphasic
Personality Inventory-2 (MMPI-2) and the Luborsky’s the Core Conflictual Relationship
Theme (CCRT), used to assess therapeutic benefit, and the Metacognition Assessment
Scale (MAS) and the Italian Discourse Attributes Analysis Program (IDAAP) system, used
to evaluate therapeutic benefit and process. The MMPI-2 was used also in the followup assessment.
Results: Results show that FP had a positive therapeutic outcome on the patients
assessed in this study, and that the therapeutic benefits were maintained over time.
Some specific features of the FP approach were found to contribute more than others
to the observed therapeutic benefits.
Conclusion: The current investigation constitutes a first step toward assessment of
the therapeutic effectiveness of FP. Future developments should apply the methodology
to a larger sample, possibly introducing different methodologies to enable detection of
specific bodily oriented processes and technique
Coupled FEM-DBEM Simulation of 3D Crack Growth under Fatigue Load Spectrum
Abstract Numerical predictions of fatigue crack growth under load spectrum are obtained by coupled FEM-DBEM approach. An initial part-through corner crack, in a pre-notched specimen undergoing a traction fatigue load, propagates becoming through the thickness. A two parameter crack growth law ("Unified Approach") is calibrated by in house made constant amplitude experimental tests and the crack growth retardation after an overload application is reproduced. The residual stresses responsible for such retardation are calculated by a sequence of elastic-plastic static FEM analysis; such stresses are then applied to the crack faces for the propagation simulation in a DBEM environment. A satisfactory agreement between numerical and experimental crack growth rates are displayed, for both part-through crack and through the thickness crack. This approach provide general modeling capabilities, with allowance for general crack front shape and fully automatic propagation
Microstructural and Mechanical Properties of Al2O3 and Al2O3/TiB2 Ceramics Consolidated by Plasma Pressure Compaction
Alumina oxide ceramics were produced by plasma pressure compaction (P2C) sintering process. Two types of pure α-alumina (Al2O3) and a mixture of alumina and titanium diboride (TiB2) powders were used as starting materials. Microstructure and mechanical properties, namely hardness, elastic modulus, and fracture toughness, were analyzed and correlated to the type of the sintered powders and the adopted manufacturing route. The microstructural development and the chemical composition variation induced by the sintering process were assessed by using scanning electron microscopy and x-ray diffraction. Nano-indentation and Chevron notch beam techniques were adopted to estimate the mechanical properties of the sintered ceramics. The conducted analyses show the capability of P2C technique to produce sound alumina ceramics. Pure alumina bulks exhibit a good level of compaction and mechanical properties close to those achievable with conventional sintering processes, such as hot isostatic pressing or spark plasma sintering. No significant alterations in the chemical composition of the ceramics were observed. The addition of the titanium diboride in the alumina powders caused a moderate increase in the grain size lowering the hardness and Young’s modulus of the sintered alumina and, at the same time, increased its fracture toughness to the occurrence of toughening mechanisms, like crack bridging and crack deflection
Clinical Presentation and Prevalence of Spontaneous Bacterial Peritonitis in Patients with Cryptogenic Cirrhosis and Features of Metabolic Syndrome
BACKGROUND: Nonalcoholic steatohepatitis (NASH) may progress to cirrhosis. The prevalence and clinical relevance that spontaneous bacterial peritonitis may have in complicating ascites due to NASH-related cirrhosis have yet to be defined
Isolation of intermediate compounds between hemoglobin and carbon monoxide.
A human hemoglobin solution partially saturated with carbon monoxide was rapidly quenched at -25 degrees C into a hydro-organic buffer containing ferricyanide. Under the experimental conditions of pH, ionic strength, and buffer composition used in this work, it was found that the deoxy hemes were rapidly transformed into their met form, whereas practically no carbon monoxide-bound hemes were oxidized before the separation of the mixture from the oxidizing agent. As a preliminary step to the analysis of the resulting solution, carbonylhemoglobin solutions partially oxidized with ferricyanide were studied by isoelectric focusing at -25 degrees C under identical conditions. The relative position in the gel of all nine possible valence hybrids was established as follows (going from the anodic to the cathodic side of the gel) alpha CO2 beta CO2, (alpha CO beta +)(alpha CO beta CO) (alpha CO beta CO), (alpha CO2 beta +2), (alpha + beta CO), (alpha + beta +)-(alpha CO beta CO), (alpha + beta +)(alpha CO beta +), (alpha +2 beta CO2), (alpha + beta +)(alpha + beta CO), alpha +2 beta +2. When carbonylhemoglobin and methemoglobin were mixed in equal proportion at -25 degrees C and then analyzed by isoelectric focusing at the same temperature, it was found that the contribution of valence hybrids other than alpha CO2 beta CO2 and alpha +2 beta +2 to the total amount of hemoglobin in the gel was no more than 6%. When carbonylhemoglobin and deoxyhemoglobin were mixed in the same proportion and incubated at 20 degrees C so to allow the redistribution of the carbon monoxide molecules between all possible binding sites to occur, a substantially higher amount of valence hybrids, derived from the oxidation of intermediate compounds of hemoglobin with carbon monoxide, was found. The isoelectric focusing separation indicated the presence in the original solution of intermediate species other than carbonylhemoglobin and deoxyhemoglobin at a concentration of about 10% of the total
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