1,157 research outputs found

    Butanol production by Clostridium pasteurianum NRRL-598 using corn steep liquor as nutrient source / Produção de butanol por Clostridium pasteurianum NRRL-598 usando licor de maceração de milho como fonte de nutrientes

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    Butanol has become an interesting substitute for ethanol in additives and fuel applications due to its physical chemical properties. Several Clostridium strains are able to produce ABE (acetone, butanol and ethanol) solvents by fermentation. Efforts have been made to reduce cost of butanol biotechnological production in order to become this route competitive when compared to petrochemical technology. This study aimed to evaluate the use of corn steep liquor, a residue of corn industry, as unique nutrient source in culture medium for butanol production by Clostridium pasteurianum NRRL B-598. The strain is capable of producing butanol using only corn steep liquor as nutrient source. The yield was 0.30 gButanol/gglucose  and the butanol productivity was 0.11 g.L-1.h-1 using 20 g.L-1 of corn steep liquor. 

    Crystal-field effects in graphene with interface-induced spin-orbit coupling

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    We consider theoretically the influence of crystalline fields on the electronic structure of graphene placed on a layered material with reduced symmetry and large spin-orbit coupling (SOC). We use a perturbative procedure combined with the Slater-Koster method to derive the low-energy effective Hamiltonian around the KK points and estimate the magnitude of the effective couplings. Two simple models for the envisaged graphene-substrate hybrid bilayer are considered, in which the relevant atomic orbitals hybridize with either top or hollow sites of the graphene honeycomb lattice. In both cases, the interlayer coupling to a crystal-field-split substrate is found to generate highly anisotropic proximity spin-orbit interactions, including in-plane 'spin-valley' coupling. Interestingly, when an anisotropic intrinsic-type SOC becomes sizeable, the bilayer system is effectively a quantum spin Hall insulator characterized by in-plane helical edge states robust against Bychkov-Rashba effect. Finally, we discuss the type of substrate required to achieve anisotropic proximity-induced SOC and suggest possible candidates to further explore crystal field effects in graphene-based heterostructures

    KITE : high-performance accurate modelling of electronic structure and response functions of large molecules, disordered crystals and heterostructures

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    We present KITE, a general purpose open-source tight-binding software for accurate real-space simulations of electronic structure and quantum transport properties of large-scale molecular and condensed systems with tens of billions of atomic orbitals (N ∼ 10^10). KITE’s core is written in C++, with a versatile Python-based interface, and is fully optimized for shared memory multi-node CPU architectures, thus scalable, efficient and fast. At the core of KITE is a seamless spectral expansion of lattice Green’s functions, which enables large-scale calculations of generic target functions with uniform convergence and fine control over energy resolution. Several functionalities are demonstrated, ranging from simulations of local density of states and photo-emission spectroscopy of disordered materials to large-scale computations of optical conductivity tensors and real-space wave-packet propagation in the presence of magneto-static fields and spin–orbit coupling. On-the-fly calculations of real-space Green’s functions are carried out with an efficient domain decomposition technique, allowing KITE to achieve nearly ideal linear scaling in its multi-threading performance. Crystalline defects and disorder, including vacancies, adsorbates and charged impurity centres, can be easily set up with KITE’s intuitive interface, paving the way to user-friendly large-scale quantum simulations of equilibrium and non-equilibrium properties of molecules, disordered crystals and heterostructures subject to a variety of perturbations and external conditions

    Efficacy of single-dose cholecalciferol in the blood pressure of patients with type 2 diabetes, hypertension and hypovitaminoses D

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    Observational and experimental data reinforce the concept that vitamin D is associated with the pathogenesis of arterial hypertension. We investigated the efect of a single dose of 100,000 IU of cholecalciferol, in ofce blood pressure (BP), and 24-h ambulatory blood pressure monitoring (ABPM) in patients with type 2 diabetes mellitus (DM), hypertension, and hypovitaminosis D. Fortythree patients were randomized to a placebo or cholecalciferol group. BP was assessed by ofce measurements and 24-h ABPM, before and after intervention. At week 8, a greater decrease in median ABPM values was observed in cholecalciferol supplementation than in the placebo group for systolic 24-h (− 7.5 vs. − 1; P= 0.02), systolic daytime (− 7 vs. − 1; P= 0.007), systolic nighttime (− 7.0 vs. 3; P= 0.009), diastolic 24-h (− 3.5 vs. − 1; P= 0.037), and daytime DBP (− 5 vs. 0; P= 0.01). Ofce DBP was also reduced after vitamin D supplementation. A single dose of vitamin D3 improves BP in patients with type 2 diabetes, hypertension, and vitamin D insufciency, regardless of vitamin D normalization. Vitamin D supplementation could be a valuable tool to treat patients with type 2 DM, hypertension, and hypovitaminosis D

    Solubility and solid phase studies of isomeric phenolic acids in pure solvents

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    The solubilities of gallic, protocatechuic, gentisic or α-resorcylic acids were measured in nine pure solvents (water, methanol, ethanol, 1-propanol, 2-propanol, 2-butanone, ethyl acetate, acetonitrile and dimethylformamide) at 298.15 K and 313.15 K, using the analytical isothermal shake-flask method. Additionally, solid phase studies of the selected phenolic acids were carried out using differential scanning calorimetry (DSC) and X-ray diffraction (XRD), giving access to important data on melting properties as well as on the structure of the solid phase before and after the dissolution. The NRTL-SAC model coupled to the reference solvent approach (RSA) were applied to correlate the solubility data in a set of seven solvents and, after used to predict the solubility in 1-propanol and dimethylformamide. Average relative deviations (ARD) between 28 and 40% for the correlation and between 16 and 59% for the predictions were obtained. These values are within the order of magnitude usually found for such type of semi-predictive models, using a limited set of data.This work is supported by: Project “AIProcMat@N2020 - Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); Project POCI-01-0145-FEDER-006984 – Associate Laboratory LSRE-LCM funded by ERDF through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI); Project POCI-01-0145-FEDER-030463 financed by COMPETE and Portugal2020 and national funds through FCT - Fundação para a Ciência e a Tecnologia . We also acknowledge the support of CICECO – Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013 ). Appendix Ainfo:eu-repo/semantics/publishedVersio

    Single nucleotide polymorphisms in Plasmodium falciparum V type H+ pyrophosphatase gene (pfvp2) and their associations with pfcrt and pfmdr1 polymorphisms

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    "Uncorrected proof"BACKGROUND: Chloroquine resistance in Plasmodium falciparum malaria has been associated with pfcrt 76T (chloroquine resistance transporter gene) and pfmdr1 86Y (multidrug resistance gene 1) alleles. Pfcrt 76T enables transport of protonated chloroquine out of the parasites digestive vacuole resulting in a loss of hydrogen ions (H(+)). V type H(+) pyrophosphatase (PfVP2) is thought to pump H(+) into the digestive vacuole. This study aimed to describe the geographic distribution of single nucleotide polymorphisms in pfvp2 and their possible associations with pfcrt and pfmdr1 polymorphisms. METHODS: Blood samples from 384 patients collected (1981-2009) in Honduras (n=35), Colombia (n=50), Liberia (n=50), Guinea Bissau (n=50), Tanzania (n=50), Iran (n=50), Thailand (n=49) and Vanuatu (n=50) were analysed. The pfcrt 72-76 haplotype, pfmdr1 copy numbers, pfmdr1 N86Y and pfvp2 V405I, K582R and P711S alleles were identified using PCR based methods. RESULTS: Pfvp2 was amplified in 344 samples. The pfvp2 allele proportions were V405 (97%), 405I (3%), K582 (99%), 582R (1%), P711 (97%) and 711S (3%). The number of patients with any of pfvp2 405I, 582R and/or 711S were as follows: Honduras (2/30), Colombia (0/46), Liberia (7/48), Guinea-Bissau (4/50), Tanzania (3/48), Iran (3/50), Thailand (1/49) and Vanuatu (0/31). The alleles were most common in Liberia (P=0.01) and Liberia+Guinea-Bissau (P=0.01). The VKP haplotype was found in 189/194 (97%) and 131/145 (90%) samples harbouring pfcrt 76T and pfcrt K76 respectively (P=0.007). CONCLUSIONS: The VKP haplotype was dominant. Most pfvp2 405I, 582R and 711S SNPs were seen where CQ resistance was not highly prevalent at the time of blood sampling possibly due to greater genetic variation prior to the bottle neck event of spreading CQ resistance. The association between the pfvp2 VKP haplotype and pfcrt 76T, which may indicate that pfvp2 is involved in CQ resistance, should therefore be interpreted with caution.This work was supported by Swedish International Development Cooperation Agency, Department for research Cooperation (Sida-SAREC Contribution no 75007082/03) and Sigurd och Elsa Goljes Minne Fund (project No. LA2010-0537). MIV is recipient of Post Doctoral fellowship from Fundacao para a Ciencia e Tecnologia (FCT)/Ministerio da Ciencia e Ensino Superior, Portugal - MCES (ref. SFRH/BPD/76614/2011). JU has a postdoctoral position funded by Stockholms lans landsting

    Dermoscopic and reflectance confocal microscopy findings in extra-genital hpv16-associated pigmented squamous cell carcinoma in situ

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    Cutaneous Oncology Department AC Camargo Cancer Center, Rua Professor Antonio Prudente, 211, São Paulo, BrazilPathology Department, AC Camargo Cancer Center, Rua Professor Antonio Prudente, 211, São Paulo, BrazilDepartment of Dermatology, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv, IsraelDermatology Department, Federal University of São Paulo, São Paulo, BrazilDermatology Department, Federal University of São Paulo, São Paulo, BrazilWeb of Scienc

    A clinical follow-up of 35 Brazilian patients with Prader-Willi Syndrome

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    OBJECTIVE: Prader-Willi Syndrome is a common etiology of syndromic obesity that is typically caused by either a paternal microdeletion of a region in chromosome 15 (microdeletions) or a maternal uniparental disomy of this chromosome. The purpose of this study was to describe the most significant clinical features of 35 Brazilian patients with molecularly confirmed Prader-Willi syndrome and to determine the effects of growth hormone treatment on clinical outcomes. METHODS: A retrospective study was performed based on the medical records of a cohort of 35 patients diagnosed with Prader-Willi syndrome. The main clinical characteristics were compared between the group of patients presenting with microdeletions and the group presenting with maternal uniparental disomy of chromosome 15. Curves for height/length, weight and body mass index were constructed and compared between Prader-Willi syndrome patients treated with and without growth hormone to determine how growth hormone treatment affected body composition. The curves for these patient groups were also compared with curves for the normal population. RESULTS: No significant differences were identified between patients with microdeletions and patients with maternal uniparental disomy for any of the clinical parameters measured. Growth hormone treatment considerably improved the control of weight gain and body mass index for female patients but had no effect on either parameter in male patients. Growth hormone treatment did not affect height/length in either gender. CONCLUSION: The prevalence rates of several clinical features in this study are in agreement with the rates reported in the literature. Additionally, we found modest benefits of growth hormone treatment but failed to demonstrate differences between patients with microdeletions and those with maternal uniparental disomy. The control of weight gain in patients with Prader-Willi syndrome is complex and does not depend exclusively on growth hormone treatment

    Subtractive phage display selection from canine visceral leishmaniasis identifies novel epitopes that mimic leishmania infantum antigens with potential serodiagnosis applications

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    Visceral leishmaniasis (VL) is a zoonotic disease that is endemic to Brazil, where dogs are the main domestic parasite reservoirs, and the percentages of infected dogs living in regions where canine VL (CVL) is endemic have ranged from 10% to 62%. Despite technological advances, some problems have been reported with CVL serodiagnosis. The present study describes a sequential subtractive selection through phage display technology from polyclonal antibodies of negative and positive sera that resulted in the identification of potential bacteriophage-fused peptides that were highly sensitive and specific to antibodies of CVL. A negative selection was performed in which phage clones were adhered to purified IgGs from healthy and Trypanosoma cruzi-infected dogs to eliminate cross-reactive phages. The remaining supernatant nonadhered phages were submitted to positive selection against IgG from the blood serum of dogs that were infected with Leishmania infantum. Phage clones that adhered to purified IgGs from the CVL-infected serum samples were selected. Eighteen clones were identified and their reactivities tested by a phage enzyme-linked immunosorbent assay (phage-ELISA) against the serum samples from infected dogs (n 31) compared to those from vaccinated dogs (n 21), experimentally infected dogs with cross-reactive parasites (n 23), and healthy controls (n 17). Eight clones presented sensitivity, specificity, and positive and negative predictive values of 100%, and they showed no crossreactivity with T. cruzi- or Ehrlichia canis-infected dogs or with dogs vaccinated with two different commercial CVL vaccines in Brazil. Our study identified eight mimotopes of L. infantum antigens with 100% accuracy for CVL serodiagnosis. The use of these mimotopes by phage-ELISA proved to be an excellent assay that was reproducible, simple, fast, and inexpensive, and it can be applied in CVL-monitoring programsThis work was supported by grants from the Pró-Reitoria de Pesquisa of UFMG (supported 03/2013), the Instituto Nacional de Ciência e Tecnologia em Nano-Biofarmacêutica (INCT Nano-Biofar), Rede Nanobiotec/Brasil-UFU (CAPES), PRONEX-FAPEMIG (APQ-01019- 09), FAPEMIG (APQ-00496-11 and APQ-00819-12), and CNPq (APQ- 472090/2011-9 and APQ-482976/2012-8). E.A.F.C. and L.R.G. are recipients of grants from CNPq. M.A.C.-F. is the recipient of a grant from FAPEMIG/CAPE

    Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.

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    Age at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
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