G-protein-coupled receptors (GPCRs) remain the primary conduit by which cells detect environmental stimuli and communicate with each other. Upon activation by extracellular agonists, these ...seven-transmembrane-domain-containing receptors interact with heterotrimeric G proteins to regulate downstream second messenger and/or protein kinase cascades. Crystallographic evidence from a prototypic GPCR, the β2-adrenergic receptor (β2AR), in complex with its cognate G protein, Gs, has provided a model for how agonist binding promotes conformational changes that propagate through the GPCR and into the nucleotide-binding pocket of the G protein α-subunit to catalyse GDP release, the key step required for GTP binding and activation of G proteins. The structure also offers hints about how G-protein binding may, in turn, allosterically influence ligand binding. Here we provide functional evidence that G-protein coupling to the β2AR stabilizes a ‘closed’ receptor conformation characterized by restricted access to and egress from the hormone-binding site. Surprisingly, the effects of G protein on the hormone-binding site can be observed in the absence of a bound agonist, where G-protein coupling driven by basal receptor activity impedes the association of agonists, partial agonists, antagonists and inverse agonists. The ability of bound ligands to dissociate from the receptor is also hindered, providing a structural explanation for the G-protein-mediated enhancement of agonist affinity, which has been observed for many GPCR–G-protein pairs. Our data also indicate that, in contrast to agonist binding alone, coupling of a G protein in the absence of an agonist stabilizes large structural changes in a GPCR. The effects of nucleotide-free G protein on ligand-binding kinetics are shared by other members of the superfamily of GPCRs, suggesting that a common mechanism may underlie G-protein-mediated enhancement of agonist affinity.
Summary
In order to reset the immune system to baseline function, autologous hematopoietic stem cell transplantation (HSCT) has been performed in patients with multiple sclerosis (MS). After June ...2015, 617 new consecutive patients with MS were autografted in our center with non‐frozen peripheral blood stem cells. The autografts were performed on an out‐patient basis, after conditioning with cyclophosphamide and rituximab. The aim of the study was the assessment of both safety and efficacy of the method. The study’s primary co‐end‐points were recovery of granulocyte and platelet counts and transplant‐related mortality. Secondary end‐points were overall survival and clinical response (improvement or stabilization of the self‐reported expanded disability status scale score). The protocol was registered in ClinicalTrials.gov identifier NCT02674217.0. We included 401 females and 216 males, with a median age of 46 years. A total of 259 patients had relapsing–remitting MS (RRMS), 228 had secondary progressive (SPMS) and 130 had primary progressive (PPMS) multiple sclerosis. All procedures were initially performed on an out‐patient basis and only 32 individuals (5%) required hospitalization. One to three aphereses (median 1) were required to harvest at least 1 × 106/kg viable CD34+ cells. The total number of viable CD34+ infused cells ranged between 1 and 37·83 × 106/kg (median 5·68). Patients recovered more than 0·5 × 109/l absolute granulocytes by day 8 (median, range = 2–14), and platelet values were above 20 × 109/l by day 4 (median, range = 0–11). Eleven individuals required red blood cells and six needed platelet transfusions. To date, there have been no deaths attributable to the transplant, yielding a 30‐month overall survival of 100%. Patients have been followed for 3–42 months (median = 12). The overall response rate (decrease or stabilization of the self‐reported EDSS score) at 12 months was 78% for all patients (83% in RRMS, 78% in PPMS and 73% in SPMS), while the disability progression‐free survival was 82% for all patients (86% in RRMS, 78·5% in SPMS and 78% in SPMS). Changes in the self‐reported EDSS score in parallel with neurological improvement were observed in people with all types of MS after HSCT, employing the ‘Mexican method’.
Changes in the self‐reported EDSS score accordant with neurological improvement, were observed in peoples with all types of MS after HSCT, employing the ‘Mexican method’.
•HT produces a cellulose rich solid with high susceptibility to enzymatic attack.•EH efficiency is negatively affected by solid loading increase.•Cellulases undergo rapid activity lose during the ...first hours of saccharification.•Horizontal bioreactors improve glucose production at high solid loadings.
One of the major challenges in biofuels production from lignocellulosic biomass is the generation of high glucose titers from cellulose in the enzymatic hydrolysis stage of pretreated biomass to guarantee a cost-effective process. Therefore, the enzymatic saccharification on cellulose at high solid loading is an alternative. In this work, the agave bagasse was hydrothermally pretreated and optimized at 194 °C/30 min, obtaining a pretreated solid rich in cellulose content (>46.46%), and subjected to enzymatic hydrolysis at high solid levels. A horizontal bioreactor was designed for enzyme saccharification at high solid loadings 25% (w/v). The bioreactor improved mixing efficiency, with cellulose conversions up to 98% (195.6 g/L at 72 h). Moreover, mathematical modeling of cellulase deactivation demonstrated that cellulases lose most of their initial activity in the first hours of the reaction. Also, cellulose was characterized by X-ray diffraction, and the pretreated solids were visualized using scanning electron microscopy.
Outer membrane vesicles (OMVs) from Gram-negative bacteria were first described more than 50 years ago. However, the molecular mechanisms involved in biogenesis began to be studied only in the last ...few decades. Presently, the biogenesis and molecular mechanisms for their release are not completely known. This review covers the most recent information on cellular components involved in OMV biogenesis, such as lipoproteins and outer membrane proteins, lipopolysaccharide, phospholipids, quorum-sensing molecules, and flagella.
•A global intercomparison of fifteen clear-sky irradiance models is proposed.•A common gridded hourly input database spanning one year is used.•Larger inter-model discrepancies found in direct ...irradiance than in global irradiance.•The highest differences found in Asia, Middle East and central and northern Africa.•Modeling improvements required for situations with high aerosol load.
Clear-sky irradiance (CSI) modeling constitutes an essential component of the evaluation of the solar resource at any location, and is involved in a large number of applications. In solar applications, most common CSI models provide broadband irradiance predictions based on a number of simplifications and/or empirical components compared to the rigorous radiative transfer models used in atmospheric sciences. Thus, these common CSI models have to undergo continuous quality assurance evaluations to delineate the range of validity of such simplifications. Traditionally, these evaluations have consisted in direct comparisons against high-quality ground observations. A review of 36 such validation studies of the literature is provided here, highlighting which CSI models were recommended over different climatic areas. This review underlines the difficulty of generalizing these results due to a number of methodological difficulties. In particular, the availability of ground observations is limited and does not cover the full extent of the atmospheric conditions over which the CSI models are regularly operated. In this review study, fifteen of the most highly cited CSI models of the literature are compared to each other using a global synthetic input database built from atmospheric reanalyses. It guarantees that most of the operating conditions of CSI models are potentially covered. The study focuses on the global horizontal (GHI) and direct normal (DNI) irradiance predictions of the CSI models. Overall, a better agreement for GHI than for DNI is found. The largest inter-model discrepancies span throughout Asia, the Middle East and central and northern Africa, precisely coinciding with some of the regions with the highest interest for solar energy applications. The most important sources of discrepancies are traced down to high loads of aerosols, high site elevations, and low solar altitudes. Usage of the Linke turbidity factor as input to a popular type of simplified CSI model is found to be a significant source of uncertainty, preventing accurate simultaneous predictions of GHI and DNI. Other models, which tend to mispredict GHI or DNI over, e.g., hazy areas, are identified.
Availability of clinically effective and cost-effective treatments for severe asthma would be beneficial to patients and national healthcare systems. The aim of this study was to evaluate clinical ...outcomes and healthcare expenditure after incorporating benralizumab into the standard treatment of refractory eosinophilic asthma.
This was a cross-sectional multicentre study of consecutive patients with refractory eosinophilic asthma who received treatment with benralizumab during at least 12 months. Patient follow-up was performed in specialised severe asthma units. The main effectiveness parameters measured were: the avoidance of one asthma exacerbation, a 3-point increase in the asthma control test (ACT) score, and the difference in utility scores (health-related quality of life) between a 1-year baseline treatment and 1-year benralizumab treatment. The health economic evaluation included direct costs and incremental cost-effectiveness ratios (ICERs).
After 1 year of treatment with benralizumab, patients with refractory eosinophilic asthma showed an improvement in all the effectiveness parameters analysed: improvement of asthma control and lung function, and decrease in the number of exacerbations, oral corticosteroid (both as corticosteroid courses and maintenance therapy), and inhaled corticosteroid use. The total annual cost per patient for the baseline and benralizumab treatment periods were €11,544 and €14,043, respectively, reflecting an increase in costs due to the price of the biological agent but a decrease in costs for the remaining parameters. The ICER was €602 per avoided exacerbation and €983.86 for every 3-point increase in the ACT score.
All the pharmacoeconomic parameters analysed show that treatment with benralizumab is a cost-effective option as an add-on therapy in patients with refractory eosinophilic asthma.
Transport models in reverse osmosis (RO) desalination have been extensively studied taking into account various factors such as temperature, fouling, etc. However, there are not many models that ...describe the behavior of a desalination plant over long time periods. These models depend on operating time and empirical parameters to estimate the flux or the average water permeability coefficient (A) decline. The proposed model separates the decline of A in two stages, the first stage refers to a more pronounced decline due to initial compaction and irreversible fouling and the second stage describes a more stable period with less slope. The model is based on the superposition of two exponential functions, which depends on operating time, empirical parameters and fouling potential of the feedwater (kfp). Ten years operating data of a brackish water reverse osmosis (BWRO) desalination plant were used. The obtained results with the proposed model showed a slightly better fit than previous models, but giving meaning to two different behaviors separated in two stages.
•New model for the estimation of the water permeability coefficient•Membrane performance decline in long-term•Operating data of a BWRO desalination plant along 10years
Summary
The circadian system, headed by the suprachiasmatic nucleus, synchronizes behaviour and metabolism according to the external light–dark cycle through neuroendocrine and autonomic signals. ...Metabolic diseases, such as steatosis, obesity and glucose intolerance, have been associated with conditions of circadian misalignment wherein the feeding schedule has been moved to the resting phase. Here we describe the physiological processes involved in liver lipid accumulation and show how they follow a circadian pattern importantly regulated by both the autonomic nervous system and the feeding–fasting cycle. We propose that an unbalanced activity of the sympathetic–parasympathetic branches between organs induced by circadian misalignment provides the conditions for the development and progression of non‐alcoholic fatty liver disease.
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