To maintain membrane homeostasis, ruminal bacteria synthesize branched-chain fatty acids (BCFA) or their derivatives (vinyl ethers) that are recovered during methylation procedures as branched-chain ...aldehydes (BCALD). Many strains of cellulolytic bacteria require 1 or more branched-chain volatile fatty acid (BCVFA). Therefore, the objective of this study was to investigate BCVFA incorporation into bacterial lipids under different dietary conditions. The study was an incomplete block design with 8 continuous culture fermenters used in 4 periods with treatments (n = 4) arranged as a 2 × 2 × 2 factorial. The factors were high (HF) or low forage (LF, 67 or 33% forage, 33:67 alfalfa:orchardgrass), without or with supplemental corn oil (CO; 3% dry matter, 1.5% linoleic fatty acid), and without or with 2.15 mmol/d (5 mg/d
C each of isovalerate, isobutyrate, and 2-methylbutyrate). After methylation of bacterial pellets collected from each fermenter's effluent, fatty acids and fatty aldehydes were separated before analysis by gas chromatography and isotope ratio mass spectrometry. Supplementation of BCVFA did not influence biohydrogenation extent. Label was only recovered in branched-chain lipids. Lower forage inclusion decreased BCFA in bacterial fatty acid profile from 9.45% with HF to 7.06% with LF and decreased BCALD in bacterial aldehyde profile from 55.4% with HF to 51.4% with LF. Supplemental CO tended to decrease iso even-chain BCFA and decreased iso even-chain BCALD in their bacterial lipid profiles. The main 18:1 isomer was cis-9 18:1, which increased (P < 0.01) by 25% from CO (data not shown). Dose recovery in bacterial lipids was 43.3% lower with LF than HF. Supplemental CO decreased recovery in the HF diet but increased recovery with LF (diet × CO interaction). Recovery from anteiso odd-chain BCFA and BCALD was the greatest; therefore, 2-methylbutyrate was the BCVFA primer most used for branched-chain lipid synthesis. Recovery in iso odd-chain fatty acids (isovalerate as primer) was greater than label recovery in iso even-chain fatty acids (isobutyrate as primer). Fatty aldehydes were less than 6% of total bacterial lipids, but 26.0% of
C recovered in lipids were recovered in BCALD because greater than 50% of aldehydes were branched-chain. Because BCFA and BCALD are important in the function and growth of bacteria, especially cellulolytics, BCVFA supplementation can support the rumen microbial consortium, increasing fiber degradation and efficiency of microbial protein synthesis.
The activation of CTLs is dependent on the recognition of MHC-bound peptide present on the surface of APCs. We give evidence in this study that differential splicing of Ag-encoding RNA can decrease ...the antigenic dose in APCs and regulate the recall of human memory CTLs. Differential splicing of RNA that encoded an immunodominant HLA-B8-restricted CTL epitope of EBV reduced the functional presentation of this epitope, and consequently the in vitro expansion and activity of CTLs, as measured by MHC/peptide-tetramer staining and cytotoxicity assays. The reduced activity of the stimulated CTLs was not only due to lower numbers of Ag-specific CTLs but, surprisingly, was also characterized by decreased cytotoxicity of the CTLs to target cells presenting limiting amounts of the peptide epitope. As indicated by TCR repertoire analysis, the reduction in CTL activity was not caused by stimulation of distinct populations of TCR clonotypes. This study demonstrates how a common eukaryotic posttranscriptional mechanism of gene regulation can modulate the endogenous presentation of Ag and ultimately contribute to the fine tuning of immunological memory cells, which are important in the fight against pathogens and tumors and in autoimmunity.
Model-Based Software Engineering provides various modelling formalisms for capturing the structural, behavioral, configuration, and intentional aspects of software systems. One of the most widely ...used kinds of models—domain models—are used during requirements analysis or the early stages of design to capture the domain concepts and relationships in the form of class diagrams. Modellers perform domain modelling to transform the problem descriptions that express informal requirements in natural language to domain models, which are more concise and analyzable. However, this manual practice of domain modelling is laborious and time-consuming. Existing approaches, which aim to assist modellers by automating or semi-automating the construction of domain models from problem descriptions, fail to address three non-trivial aspects of automated domain modelling. First, automatically extracted domain models from existing approaches are not accurate enough to be used directly or with minor modifications for software development or teaching purposes. Second, existing approaches do not support modeller-system interactions beyond providing recommendations. Finally, existing approaches do not facilitate the modellers to learn the rationale behind the modelling decisions taken by an extractor system. Therefore, in this paper, we extend our previous work to facilitate bot-modeller interactions. We propose an algorithm to discover alternative configurations during bot-modeller interactions. Our bot uses this algorithm to find alternative configurations and then present these configurations in the form of suggestions to modellers. Our bot then updates the domain model in response to the acceptance of these suggestions by a modeller. Furthermore, we evaluate the bot for its effectiveness and performance for the test problem descriptions. Our bot achieves median F1 scores of 86%, 91%, and 90% in the
Found Configurations
,
Offered Suggestions
, and
Updated Domain Models
categories, respectively. We also show that the median time taken by our bot to find alternative configurations is 55.5ms for the problem descriptions which are similar to the test problem descriptions in terms of model size and complexity. Finally, we conduct a pilot user study to assess the benefits and limitations of our bot and present the lessons learned from our study in preparation for a large-scale user study.
Summary
We examined heart rate variability (HRV) during exercise testing in 20 children with sickle cell anaemia (SCA) and 12 controls. Subjects achieved lower median HRV at peak exercise standard ...deviation of R‐wave to R‐wave intervals (SDNN), 2·3 vs 2·9 ms, P = 0·027; logarithmic transformation of high frequency power (lnHF), 0·9 vs 1·3 ln(ms2), P = 0·047 and had lower post‐exercise HRV across minute‐by‐minute analysis of recovery. After adjustment for haemoglobin, fitness and SCA status, subjects had lower HRV at the end of recovery with differences increasing as baseline HRV increased. Further investigation of HRV and exercise safety in SCA is warranted.
The role of water adsorption on Ti-rich SrTiO3(001) surface reconstructions is studied. Density functional calculations with hybrid functionals of numerous adsorption configurations indicate that the ...relative stability of the different reconstructions is strongly altered by the addition of water, with all the reconstructions having comparable energy for half-monolayer coverage, most with a fair degree of hydrogen bonding. This strongly suggests that which reconstruction is observed depends upon a competition between the kinetics of ordering and dehydration. X-ray photoelectron spectra are consistent with the theoretical predictions for the dehydration of the 2×1 and c(4×2) reconstructions.
► DFT is used to calculate surface energies for dry and hydrated SrTiO3(001) surfaces. ► Low-energy H2O adsorption geometries are identified for Ti-rich reconstructions. ► The formation of the low-energy dry RT2 structure is found to be kinetically limited. ► Surface reconstruction depends on competition of dehydration and desorption kinetics. ► XPS spectra support relative H2O adsorption behavior for 2×1 and c(4×2) surfaces.
The Epstein–Barr virus (EBV) encoded nuclear antigens, EBNA-3, -4, and -6 (EBNA 3 family) are expressed in latently infected human B-cells and are involved in the transformation of lymphocytes by ...EBV. Human Burkitt's lymphoma (BL) dG75 cells which stably expressed either the complete EBNA 3 gene family or the vector alone were generated and changes in gene activity in these transfectants were assayed using the differential display of mRNA technique. For the first time, the human gene pleckstrin, which is thought to be involved in signalling and differentiation of hemopoietic cells, was found to be upregulated in the presence of the EBNA 3 protein family, but not in cells expressing the individual EBNA-3, -4, or -6 gene. Pleckstrin was increased up to sevenfold in different cell clones and the bulk culture of EBNA 3 gene family expressing cells as demonstrated by Northern blot, RT-PCR, and immunoblot. In contrast to EBV-negative BL cells, pleckstrin RNA and protein were highly expressed in EBV growth transformed lymphoblastoid cell lines which are thought to play an important role in EBV persistencein vivo.These data suggest that induction of pleckstrin might be important for the EBV-controlled activation of cells and offers a unique biological system for analyzing pleckstrin function.
Neutron interferometry uniquely combines neutron imaging and scattering methods to enable characterization of multiple length scales from 1 nm to 10 µm. However, building, operating, and using such ...neutron imaging instruments poses constraints on the acquisition time and on the number of measured images per sample. Experiment time-constraints yield small quantities of measured images that are insufficient for automating image analyses using supervised artificial intelligence (AI) models. One approach alleviates this problem by supplementing annotated measured images with synthetic images. To this end, we create a data-driven simulation framework that supplements training data beyond typical data-driven augmentations by leveraging statistical intensity models, such as the Johnson family of probability density functions (PDFs). We follow the simulation framework steps for an image segmentation task including Estimate PDFs
Validate PDFs
Design Image Masks
Generate Intensities
Train AI Model for Segmentation. Our goal is to minimize the manual labor needed to execute the steps and maximize our confidence in simulations and segmentation accuracy. We report results for a set of nine known materials (calibration phantoms) that were imaged using a neutron interferometer acquiring four-dimensional images and segmented by AI models trained with synthetic and measured images and their masks.
The potentiometric behavior of xanthan solutions was analyzed as a function of ionic strength, polymer concentration and temperature. For a given value of the polymer dissociation constant, alpha, ...pKa was linearly correlated with Cs1/3 (salt concentration). At polymer concentrations below 7.5 g liter-1, pKa was a function of polymer concentration. However, when the polymer concentration was higher than this value, pKa was independent of polymer concentration. Potentiometric titration confirmed the significance of the hydrogen bond and the carboxylate group on the secondary structure of xanthan which suggested that the ordered xanthan conformation is stabilized mainly by hydrogen bonds. These can be disrupted by increasing the electrostatic potential of the molecule or by increasing the solution temperature. Neither the ionic strength nor the polymer concentration affected the secondary structure of xanthan at 25 degrees C. However, ionic strength should reduce the repulsive force between charged groups in xanthan; this would explain the salt stabilization of the secondary structure observed at the higher test temperatures (35-70 degrees C).
Selective alkylation of pyrazoles could solve a challenge in chemistry and streamline synthesis of important molecules. Here we report catalyst‐controlled pyrazole alkylation by a cyclic two‐enzyme ...cascade. In this enzymatic system, a promiscuous enzyme uses haloalkanes as precursors to generate non‐natural analogs of the common cosubstrate S‐adenosyl‐l‐methionine. A second engineered enzyme transfers the alkyl group in highly selective C−N bond formations to the pyrazole substrate. The cosubstrate is recycled and only used in catalytic amounts. Key is a computational enzyme‐library design tool that converted a promiscuous methyltransferase into a small enzyme family of pyrazole‐alkylating enzymes in one round of mutagenesis and screening. With this enzymatic system, pyrazole alkylation (methylation, ethylation, propylation) was achieved with unprecedented regioselectivity (>99 %), regiodivergence, and in a first example on preparative scale.
Biological alkylation is highly selective, yet it depends on complex leaving groups. Now, promiscuous and engineered enzymes achieve selective enzymatic alkylation using simple haloalkanes.
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