A general binary isotherm model for amines interacting with CO2 and H2O.

CO2 capture by primary or secondary amines has been a topic of great research interests for a century because of its industrial importance. Interest has grown even more, because of the need to eliminate CO2 emissions that lead to global warming. Experimental evidence shows that CO2 sorption by primary or secondary amines is accompanied by co-absorption of H2O. A quantitative analysis of such CO2-H2O co-absorption behavior is important for practical process design and theoretical understanding. Even though there is almost an experimental consensus that water enhances CO2 uptake capacity, an analytical model to explain this phenomenon is not well established. Instead, some empirical models such as the Toth model are used to describe the isotherm without accounting for the presence of water. Recently, we have demonstrated that the isotherm equation of CO2 sorption into strong-base anion exchange materials with quaternary ammonium can be derived from that of strong-base aqueous alkaline solutions by correcting for the drastic change in the water activity and by including an appropriate parameterization of the water activity terms. In this paper, we generalize this model from quaternary ammonium to primary, secondary and tertiary amines either in solutions or as functional groups in polymer resins. For primary, secondary and tertiary amines, the isotherm equation can be derived by extending that of a weak-base aqueous alkaline solution such as aqueous ammonia. The model has been validated using experimental data on CO2 sorption for aqueous ammonia from the literature. This general model even includes quaternary ammonium as a special limit. Hence, this general model offers a platform that can treat the isotherms of solid amines, aqueous amines and aqueous alkaline solutions in a unified manner.

Confronting the Carbon-Footprint Challenge of Blockchain.

The distributed consensus mechanism is the backbone of the rapidly developing blockchain network. Blockchain platforms consume vast amounts of electricity based on the current consensus mechanism of Proof-of-Work (PoW). Here, we point out a different consensus mechanism named Proof-of-Stake (PoS) that can eliminate the extensive energy consumption of the current PoW-based blockchain. We comprehensively elucidate the current and projected energy consumption and carbon footprint of the PoW- and PoS-based Bitcoin and Ethereum blockchain platforms. The model of energy consumption of PoS-based Ethereum blockchain can lead the way toward the prediction of other PoS-based blockchain technologies in the future. With the widespread adoption of blockchain technology, if the current PoW mechanism continues to be employed, the carbon footprint of Bitcoin and Ethereum will push the global temperature above 1.5 °C in this century. However, a PoS-based blockchain can reduce the carbon footprint by 99% compared to the PoW mechanism. The small amount of carbon footprint from PoS-based blockchain could make blockchain an attractive technology in a carbon-constrained future. The study sheds light on the urgency of developing the PoS mechanism to solve the current sustainability problem of blockchain.

Kinetic model for moisture-controlled CO2 sorption.

The understanding of the sorption/desorption kinetics is essential for practical applications of moisture-controlled CO2 sorption. We introduce an analytic model of the kinetics of moisture-controlled CO2 sorption and its interpretation in two limiting cases. In one case, chemical reaction kinetics on pore surfaces dominates, in the other case, diffusive transport through the sorbent defines the kinetics. We show that reaction kinetics, which is dominant in the first case, can be expressed as a linear combination of 1st and 2nd order kinetics in agreement with the static isotherm equation derived and validated in a previous paper. The interior transport kinetics can be described by non-linear diffusion equations. By combining all carbon species into a single equation, we can eliminate - in certain limits - the source terms associated with chemical reactions. In this case, the governing equation is . For a sorbent in a form of a flat sheet or a membrane, one can maintain the same functional form of a diffusion equation by introducing a generalized effective diffusivity DM that combines contributions from both surface chemical reaction kinetics and interior diffusive transport kinetics. Experimental data of transient CO2 flux in a preconditioned commercial anion exchange membrane fit well to the 1st order model as long as very dry states are avoided, validating the theory. The observed DM for a preconditioned commercial anion exchange membrane ranges from 6.6 × 10-14 to 7.1 × 10-14 m2 s-1 at 35 °C. These small values compared to typical ionic diffusivities imply a very slow kinetics, which will be the largest issue that needs to be addressed for practical application. The collected transient CO2 flux data are used to predict the magnitude of a continuous CO2 pumping flux in an active membrane that transports CO2 against a CO2 concentration gradient. The pumped CO2 flux is supported by water flux due to a water concentration gradient.

Isotherm model for moisture-controlled CO2 sorption.

Moisture-controlled sorption of CO2, the basis for moisture-swing CO2 capture from air, is a novel phenomenon observed in strong-base anion exchange materials. Prior research has shown that Langmuir isotherms provide an approximate fit to moisture-controlled CO2 sorption isotherm data. However, this fit still lacks a governing equation derived from an analytic model. In this paper, we derive an analytic form for an isotherm equation from a bottom-up approach, starting with a fundamental theory for an alkali liquid. In the range of interest relevant to CO2 capture from air, an isotherm equation for an alkali liquid reduces to a simple analytic form with a single parameter, Keq. In the limit Keq ≫ 1, a 2nd order approximation simplifies to a Langmuir isotherm that, however, deviates from experimental data. The isotherm theory for an alkali liquid has been generalized to a strong-base anion exchange material. In a strong-base anion exchange material, water concentration inside a sorbent, [H2O], is not large enough to be regarded as constant, which allows us to extend Keq to Keq(AEM)eff = Keq(AEM) × [H2O]-n according to the law of mass action. The final isotherm formula has been validated by experimental data from the literature. For a moisture-controlled CO2 sorbent, Keq(AEM)eff varies significantly with moisture content of the sorbent. Depending on moisture level, the observed Keq(AEM)eff in a specific sorbent ranges from a few times to a few thousand times the value of Keq of a 2 mol L-1 alkali liquid.

In vitro cell cultures of Brunner's glands from male mouse to study GLP-1 receptor function.

Exocrine glands in the submucosa of the proximal duodenum secrete alkaline fluid containing mucus to protect the intestinal mucosa from acidic stomach contents. These glands, known as Brunner's glands, express high glucagon-like peptide 1 receptor (GLP-1R) levels. Previous studies have suggested that activation of the GLP-1R induces expression of barrier protective genes in Brunner's glands. Still, the lack of a viable in vitro culture of Brunner's glands has hampered additional studies of the functional consequences of GLP-1R activation. In this study, we established a procedure to isolate and culture cells derived from murine Brunner's glands. The isolated glandular cells retained functional GLP-1R expression in culture, making this in vitro system suitable for the study of GLP-1R activation. We found that cells derived from the Brunner's glands of mice pretreated with semaglutide contained significantly more mucus compared with Brunner's glands from vehicle-treated mice. Our data suggest a protective intestinal response upon semaglutide treatment, but further studies are required to leverage the full potential of cultured Brunner's gland cells.

Systems genetics in the rat HXB/BXH family identifies Tti2 as a pleiotropic quantitative trait gene for adult hippocampal neurogenesis and serum glucose.

Neurogenesis in the adult hippocampus contributes to learning and memory in the healthy brain but is dysregulated in metabolic and neurodegenerative diseases. The molecular relationships between neural stem cell activity, adult neurogenesis, and global metabolism are largely unknown. Here we applied unbiased systems genetics methods to quantify genetic covariation among adult neurogenesis and metabolic phenotypes in peripheral tissues of a genetically diverse family of rat strains, derived from a cross between the spontaneously hypertensive (SHR/OlaIpcv) strain and Brown Norway (BN-Lx/Cub). The HXB/BXH family is a very well established model to dissect genetic variants that modulate metabolic and cardiovascular diseases and we have accumulated deep phenome and transcriptome data in a FAIR-compliant resource for systematic and integrative analyses. Here we measured rates of precursor cell proliferation, survival of new neurons, and gene expression in the hippocampus of the entire HXB/BXH family, including both parents. These data were combined with published metabolic phenotypes to detect a neurometabolic quantitative trait locus (QTL) for serum glucose and neuronal survival on Chromosome 16: 62.1-66.3 Mb. We subsequently fine-mapped the key phenotype to a locus that includes the Telo2-interacting protein 2 gene (Tti2)-a chaperone that modulates the activity and stability of PIKK kinases. To verify the hypothesis that differences in neurogenesis and glucose levels are caused by a polymorphism in Tti2, we generated a targeted frameshift mutation on the SHR/OlaIpcv background. Heterozygous SHR-Tti2+/- mutants had lower rates of hippocampal neurogenesis and hallmarks of dysglycemia compared to wild-type littermates. Our findings highlight Tti2 as a causal genetic link between glucose metabolism and structural brain plasticity. In humans, more than 800 genomic variants are linked to TTI2 expression, seven of which have associations to protein and blood stem cell factor concentrations, blood pressure and frontotemporal dementia.

Histone H4 lysine 20 mono-methylation directly facilitates chromatin openness and promotes transcription of housekeeping genes.

Histone lysine methylations have primarily been linked to selective recruitment of reader or effector proteins that subsequently modify chromatin regions and mediate genome functions. Here, we describe a divergent role for histone H4 lysine 20 mono-methylation (H4K20me1) and demonstrate that it directly facilitates chromatin openness and accessibility by disrupting chromatin folding. Thus, accumulation of H4K20me1 demarcates highly accessible chromatin at genes, and this is maintained throughout the cell cycle. In vitro, H4K20me1-containing nucleosomal arrays with nucleosome repeat lengths (NRL) of 187 and 197 are less compact than unmethylated (H4K20me0) or trimethylated (H4K20me3) arrays. Concordantly, and in contrast to trimethylated and unmethylated tails, solid-state NMR data shows that H4K20 mono-methylation changes the H4 conformational state and leads to more dynamic histone H4-tails. Notably, the increased chromatin accessibility mediated by H4K20me1 facilitates gene expression, particularly of housekeeping genes. Altogether, we show how the methylation state of a single histone H4 residue operates as a focal point in chromatin structure control. While H4K20me1 directly promotes chromatin openness at highly transcribed genes, it also serves as a stepping-stone for H4K20me3-dependent chromatin compaction.

The Current Status of Spinal Posttraumatic Deformity: A Systematic Review.

STUDY DESIGN: Systematic Review. OBJECTIVE: To systematically analyze the definitions and descriptions in literature of "Spinal Posttraumatic Deformity" (SPTD) in order to support the development of a uniform and comprehensive definition of clinically relevant SPTD. METHODS: A literature search in 11 international databases was performed using "deformity" AND "posttraumatic" and its synonyms. When an original definition or a description of SPTD (Patient factors, Radiological outcomes, Patient Reported Outcome Measurements and Surgical indication) was present the article was included. The retrieved articles were assessed for methodological quality and the presented data was extracted. RESULTS: 46 articles met the inclusion criteria. "Symptomatic SPTD" was mentioned multiple times as an entity, however any description of "symptomatic SPTD" was not found. Pain was mentioned as a key factor in SPTD. Other patient related parameters were (progression of) neurological deficit, bone quality, age, comorbidities and functional disability. Various ways were used to determine the amount of deformity on radiographs. The amount of deformity ranged from not deviant for normal to >30°. Sagittal balance and spinopelvic parameters such as the Pelvic Incidence, Pelvic Tilt and Sacral Slope were taken into account and were used as surgical indicators and preoperative planning. The Visual Analog Scale for pain and the Oswestry Disability Index were used mostly to evaluate surgical intervention. CONCLUSION: A clear-cut definition or consensus is not available in the literature about clinically relevant SPTD. Our research acts as the basis for international efforts for the development of a definition of SPTD.

Semaglutide lowers body weight in rodents via distributed neural pathways.

Semaglutide, a glucagon-like peptide 1 (GLP-1) analog, induces weight loss, lowers glucose levels, and reduces cardiovascular risk in patients with diabetes. Mechanistic preclinical studies suggest weight loss is mediated through GLP-1 receptors (GLP-1Rs) in the brain. The findings presented here show that semaglutide modulated food preference, reduced food intake, and caused weight loss without decreasing energy expenditure. Semaglutide directly accessed the brainstem, septal nucleus, and hypothalamus but did not cross the blood-brain barrier; it interacted with the brain through the circumventricular organs and several select sites adjacent to the ventricles. Semaglutide induced central c-Fos activation in 10 brain areas, including hindbrain areas directly targeted by semaglutide, and secondary areas without direct GLP-1R interaction, such as the lateral parabrachial nucleus. Automated analysis of semaglutide access, c-Fos activity, GLP-1R distribution, and brain connectivity revealed that activation may involve meal termination controlled by neurons in the lateral parabrachial nucleus. Transcriptomic analysis of microdissected brain areas from semaglutide-treated rats showed upregulation of prolactin-releasing hormone and tyrosine hydroxylase in the area postrema. We suggest semaglutide lowers body weight by direct interaction with diverse GLP-1R populations and by directly and indirectly affecting the activity of neural pathways involved in food intake, reward, and energy expenditure.

Postcombustion Capture or Direct Air Capture in Decarbonizing US Natural Gas Power?

This analysis investigates the cost of carbon capture from the US natural gas-fired electricity generating fleet comparing two technologies: postcombustion capture and direct air capture (DAC). Many of the existing natural gas combined cycle (NGCC) units are suitable for postcombustion capture. We estimated the cost of postcombustion retrofits and investigated the most important unit characteristics contributing to this cost. Units larger than 400 MW, younger than 14 years, more efficient than 45%, and with a utilization (capacity factor) higher than 0.5 were found to be the most promising for retrofit. Counterintuitively, DAC (which is usually not considered for point-source capture) may be cheaper in addressing emissions from nonretrofittable NGCC units. DAC can also address the residual emissions from retrofitted units. Moreover, the economic challenges of postcombustion capture for small natural gas-fired units with low utilization, such as gas turbines, make DAC look favorable for these units. After considering the cost of postcombustion capture for the entire natural gas-related emissions and incorporating the impact of learning-by-doing for both carbon capture technologies, our results show that DAC is the cheaper capture solution for at least 1/3 of all emissions.

Rainfall manipulation experiments as simulated by terrestrial biosphere models: Where do we stand?

Changes in rainfall amounts and patterns have been observed and are expected to continue in the near future with potentially significant ecological and societal consequences. Modelling vegetation responses to changes in rainfall is thus crucial to project water and carbon cycles in the future. In this study, we present the results of a new model-data intercomparison project, where we tested the ability of 10 terrestrial biosphere models to reproduce the observed sensitivity of ecosystem productivity to rainfall changes at 10 sites across the globe, in nine of which, rainfall exclusion and/or irrigation experiments had been performed. The key results are as follows: (a) Inter-model variation is generally large and model agreement varies with timescales. In severely water-limited sites, models only agree on the interannual variability of evapotranspiration and to a smaller extent on gross primary productivity. In more mesic sites, model agreement for both water and carbon fluxes is typically higher on fine (daily-monthly) timescales and reduces on longer (seasonal-annual) scales. (b) Models on average overestimate the relationship between ecosystem productivity and mean rainfall amounts across sites (in space) and have a low capacity in reproducing the temporal (interannual) sensitivity of vegetation productivity to annual rainfall at a given site, even though observation uncertainty is comparable to inter-model variability. (c) Most models reproduced the sign of the observed patterns in productivity changes in rainfall manipulation experiments but had a low capacity in reproducing the observed magnitude of productivity changes. Models better reproduced the observed productivity responses due to rainfall exclusion than addition. (d) All models attribute ecosystem productivity changes to the intensity of vegetation stress and peak leaf area, whereas the impact of the change in growing season length is negligible. The relative contribution of the peak leaf area and vegetation stress intensity was highly variable among models.

Cefuroxime pharmacokinetics and pharmacodynamics for intravenous dosage regimens with 750 mg or 1500 mg doses in healthy young volunteers.

Introduction. Cefuroxime is an important antibiotic to treat several serious infections. Rapid elimination through the kidneys and the variation in MICs of various susceptible pathogens such as Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus and Streptococcus pneumoniae give rise to dosing issues, especially in otherwise healthy patients.Aim. To investigate the probability of target attainment (PTA) for obtaining the optimal dosage regimens for cefuroxime in healthy young people.Methodology. Two weeks apart 750 and 1500 mg cefuroxime were administered as an intravenous bolus to 20 healthy volunteers (mean age: 27 years). Population modelling and simulation studies were done based on the obtained data for cefuroxime plasma concentration.Results. With a target value of time above MIC (T >MIC) greater than 50 % the simulations revealed that a PTA of >99 % is obtained for S. pneumoniae with a dosage regimen of 750 mg q12h. For E. coli and K. pneumoniae the PTA was <90 % even with the highest, simulated dosage of 1500 mg q6h. For S. aureus a dosage of 1500 mg q8h gave a PTA above 97 %.Conclusions. S. pneumoniae is most likely treatable with a two-daily dose of 750 mg cefuroxime. Not treatable are K. pneumoniae and E. coli. For S. aureus 1500 mg q8h constitutes an optimal dosing schedule.

Sorbents for the Direct Capture of CO2 from Ambient Air.

The urgency to address global climate change induced by greenhouse gas emissions is increasing. In particular, the rise in atmospheric CO2 levels is generating alarm. Technologies to remove CO2 from ambient air, or "direct air capture" (DAC), have recently demonstrated that they can contribute to "negative carbon emission." Recent advances in surface chemistry and material synthesis have resulted in new generations of CO2 sorbents, which may drive the future of DAC and its large-scale deployment. This Review describes major types of sorbents designed to capture CO2 from ambient air and they are categorized by the sorption mechanism: physisorption, chemisorption, and moisture-swing sorption.

Anti-TNF treatment negatively regulates human CD4+ T-cell activation and maturation in vitro, but does not confer an anergic or suppressive phenotype.

TNF-blockade has shown clear therapeutic value in rheumatoid arthritis and other immune-mediated inflammatory diseases, however its mechanism of action is not fully elucidated. We investigated the effects of TNF-blockade on CD4+ T cell activation, maturation, and proliferation, and assessed whether TNF-inhibitors confer regulatory potential to CD4+ T cells. CyTOF and flow cytometry analysis revealed that in vitro treatment of human CD4+ T cells with the anti-TNF monoclonal antibody adalimumab promoted IL-10 expression in CD4+ T cells, whilst decreasing cellular activation. In line with this, analysis of gene expression profiling datasets of anti-TNF-treated IL-17 or IFN-γ-producing CD4+ T cells revealed changes in multiple pathways associated with cell cycle and proliferation. Kinetics experiments showed that anti-TNF treatment led to delayed, rather than impaired T-cell activation and maturation. Whilst anti-TNF-treated CD4+ T cells displayed some hyporesponsiveness upon restimulation, they did not acquire enhanced capacity to suppress T-cell responses or modulate monocyte phenotype. These cells however displayed a reduced ability to induce IL-6 and IL-8 production by synovial fibroblasts. Together, these data indicate that anti-TNF treatment delays human CD4+ T-cell activation, maturation, and proliferation, and this reduced activation state may impair their ability to activate stromal cells.

Molecular cloning, expression and characterization of Pekin duck programmed death-1.

Programmed death-1 (PD-1) has a pivotal role in the attenuation of adaptive immune responses and peripheral tolerance. Here we describe the identification of the Pekin duck programmed death-1 orthologue (duPD-1). The duPD-1 cDNA encodes a 283-amino acid polypeptide that has an amino acid identity of 70%, 32% and 31% with chicken, murine and human PD-1, respectively. The duck PD-1 gene shares five conserved exons with chicken, murine and human PD-1 genes. A cluster of putative regulatory elements within the conserved region B (CR-B) of the basal promotor is conserved. Homology modeling was most compatible with the two ß-sheet IgV domain structure of murine PD-1. Contact residues, shown to be critical for binding of the respective human and murine PD-1 ligands are mostly conserved between avian and mammalian species, whereas residues that define the cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM) and immunoreceptor tyrosine-based switch motif (ITSM) are highly conserved across higher vertebrates and frog. Constitutive expression of duPD-1 transcripts was predominantly found in lymphocyte-rich tissues, and mitogen-stimulation of duck peripheral blood mononuclear cells transiently increased duPD-1 mRNA expression. A soluble duPD-1 protein was expressed and shown to engage the identified duck PD-1 ligands. Our observations show considerable evolutionary conservation between mammalian and avian PD-1 orthologues. This work will facilitate further investigation of the role of PD-1 signaling in adaptive immunity in the Pekin duck, a non-mammalian vertebrate and pathogen host with relevance for human and animal health.

Large loss of CO2 in winter observed across the northern permafrost region.

Recent warming in the Arctic, which has been amplified during the winter1-3, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)4. However, the amount of CO2 released in winter is highly uncertain and has not been well represented by ecosystem models or by empirically-based estimates5,6. Here we synthesize regional in situ observations of CO2 flux from arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1662 Tg C yr-1 from the permafrost region during the winter season (October through April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (-1032 Tg C yr-1). Extending model predictions to warmer conditions in 2100 indicates that winter CO2 emissions will increase 17% under a moderate mitigation scenario-Representative Concentration Pathway (RCP) 4.5-and 41% under business-as-usual emissions scenario-RCP 8.5. Our results provide a new baseline for winter CO2 emissions from northern terrestrial regions and indicate that enhanced soil CO2 loss due to winter warming may offset growing season carbon uptake under future climatic conditions.

[Lab on a Chip]. / "Lab on a Chip".

BACKGROUND: Miniaturization has not only driven microelectronics and generated new unforeseen options but has also dramatically changed sensors and analytics. DEVELOPMENTS: The Lab on a Chip (LOC) technology enables laboratory processes to run fully automated in canals in the micrometre range. The biggest challenge for LOC is to keep production costs low despite miniaturization and application-specific design. If this is achieved medical laboratory analyses can usually be carried out faster and with less hands on time. This explains why LOCs are already integrated into many laboratory instruments and why point-of-care testing (POCT) can no longer be imagined without it. New markers, such as in liquid biopsies and measurement techniques, such as Raman spectroscopy and mass spectroscopy, create further potentials that will enable faster and more specific laboratory analyses to be made using LOC technology. CONCLUSION: The LOC technology has the potential of changing the medical practice especially in cases when the central laboratory is not available or is unable to provide results fast enough.

Humidity effect on ion behaviors of moisture-driven CO2 sorbents.

Ion hydration is a fundamental process in many natural phenomena. This paper presents a quantitative analysis, based on atomistic modeling, of the behavior of ions and the impact of hydration in a novel CO2 sorbent. We explore moisture-driven CO2 sorbents focusing on diffusion of ions and the structure of ion hydration complexes forming inside water-laden resin structures. We show that the stability of the carbonate ion is reduced as the water content of the resin is lowered. As the hydration cloud of the carbonate ion shrinks, it becomes energetically favorable to split a remaining water molecule and form a bicarbonate ion plus a hydroxide ion. These two ions bind less water than a single, doubly charged carbonate ion. As a result, under relatively dry conditions, more OH- ions are available to capture CO2 than in the presence of high humidity. Local concentrations of dissolved inorganic carbon and water determine chemical equilibria. Reaction kinetics is then driven to a large extent by diffusion rates that allow water and anions to move through the resin structure. Understanding the basic mechanics of chemical equilibria and transport may help us to rationally design next-generation efficient moisture-driven CO2 sorbents.

Temporal Regulation of Glomerular and Cortical Tubulointerstitial Genes Involved in the Development of Nephrotoxic Serum Nephritis.

BACKGROUND/AIMS: Murine nephrotoxic nephritis (NTN) is a well-established model resembling chronic kidney disease. Investigating gene expression patterns separately in the glomerular and cortical tubulointerstitial structure could provide new knowledge about structure-specific changes in expression of genes in the NTN model. METHODS: Glomerular, cortical tubulointerstitial and whole kidney tissues from mice subjected to nephrotoxic serum (NTS) or phosphate buffered saline (PBS) were collected on day 7, 21 and 42 using laser microdissection (LMD). Total RNA was extracted and subjected to nCounter NanoString. Histology, immunohistochemistry, in situ hybridization and/or quantitative real time PCR (qRT PCR) were performed to confirm regulation of selected genes. RESULTS: LMD provided detailed information about genes that were regulated differently between structures over time. Some of the fibrotic and inflammatory genes (Col1a1, Col3a1 and Ccl2) were upregulated in both structures, whereas other genes such as Spp1 and Grem1 were differentially regulated suggesting spatial pathogenic mechanisms in the kidney. Downregulation of cortical tubulointerstitium genes involved in iron metabolism was detected along with iron accumulation. CONCLUSION: This study demonstrates several regulated genes in pathways important for the pathogenesis of the NTN model and that LMD identifies structure-specific changes in gene expression during disease development. Furthermore, this study shows the benefits of isolating glomeruli and cortical tubulointerstitium in order to identify gene regulation.

Prevalence and risk factors for bluetongue in the State of São Paulo, Brazil.

Bluetongue (BT), caused by Bluetongue virus (BTV), is a disease that affects ruminants such as cattle, sheep, goats and deer. BTV is transmitted by female midges of the genus Culicoides. In Brazil, information on the prevalence of BTV in cattle is limited, so the objective of this work was to identify BTV serotypes in cattle. The State of São Paulo was divided into seven cattle-producing regions, and in each of them, 300 cattle farms were randomly selected. One animal from each farm (out of a total of 1,598 farms) was selected and its sera tested by virus neutralization technique against BTV serotypes (1-24 and 26) for determining antibody titre. Moreover, for each sampled farm, an epidemiological questionnaire was submitted to verify the type of cattle production and the zootechnical and sanitary practices carried out, which could be associated with a higher risk of BTV infection. In this study, antibodies (percentage, [95% confidence interval]) were identified against 11 serotypes: BTV-1 (22.15%, [15.72-27.92]), BTV-2 (31.03%, [26.65-37.98]), BTV-3 (18.96%, [12.42-24.90]), BTV-4 (24.90% [19.41-29.12]), BTV-9 (6.82%, [1.45-11.72]), BTV-12 (7.50%, [2.82-12.51]), BTV-17 (23.90%, [17.35-29.35]), BTV-19 (10.20%, [4.62-5.56]), BTV-21 (30.66%, [25.00-36.00]), BTV-22 (12.14%, [5.91-18.55]), BTV-26 (57.00%, [51.41-63.59]). In this study, for the first time in Brazil serological evidence of the presence of serotypes BTV-2, BTV-9, BTV-21 and BTV-26 is reported. The variable 'new cattle entering herd' was considered a risk factor for the occurrence of infection (OR = 2.183, 95% CI = 1.6-2.9).