Kinetics of Chlorination of Tantalum Pentoxide with Carbon Tetrachloride

Tantalum chloride is used as a feed material for the plasma reduction using hydrogen and in the chloride bath fused salt electrolysis routes to produce tantalum. Most of the tantalum, however, occurs in nature in the oxide form. The traditional chlorination process employs gaseous chlorine and carbon as reductant at high temperatures (1073-1273 K). Use of carbon tetrachloride as the chlor- inating agent is expected to reduce the chlorination tem-peratures significantly resulting in lower energy cons-umption and cost of capital equipment for chlorination. The purpose of the present study was to explore the use of carbon tetrachloride as an alternative chlorinating agent for Ta205. The kinetics of chlorination of pure tantalum pentoxide powders with carbon tetrachloride in nitrogen atmosphere was investigated in the temperature range 733-853 K and Pccia in the range 20-60 kPa. The kinetic results were found to conform to a diffusion controlled reaction model. Equilibrium conversions to chloride and the gas phase composition at different temperatures and partial pressures of CCI4 were calculated using the free energy minimisation technique

A New Quantitative Classification of the Extrahepatic Biliary Tract Related to Cystic Duct Implantation

Background: Knowledge regarding biliary anatomy and its variations, including the cystic duct (CD), is important in the pre-surgical setting and for predicting biliary diseases. However, no large series has focused on CD evaluation using a quantitative analysis. The primary aim of this prospective study was to create a ‘taxonomic’ classification of CD anatomy in a large cohort of subjects who underwent magnetic resonance cholangiopancreatography (MRCP). The secondary aim was to evaluate the correlations between extrahepatic bile duct (EHBD) variants and biliary diseases. Methods: We enrolled patients who underwent MRCP for different clinical indications from January 2017 to May 2019. Demographical, anatomical and clinical data were evaluated using statistical analyses, as appropriate. The anatomical assessment of EHBD was performed using the standard classification for CD in low, medium, and high insertions, and the lengths of CD to the duodenal papilla (DP), and EHBD was determined to conduct a new quantitative analysis. Results: The final study population comprised 1004 subjects. A new classification for EHBD as per the percentile distribution of the ratio CDDP/EHBD was designed, and the following categories were obtained: type 1 (below the 25th percentile) for CDDP/EHBD ratio ≤ 50%; type 2 (25th to 75th percentile) for CDDP/EHBD ratio 51–75% and type 3 (above the 75th percentiles) for CDDP/EHBD ratio > 75%. Type 1 of the new classification of CD implantation was significantly superior in terms of the detection of low, medial and intra-pancreatic CD that was significantly correlated with a high risk of choledochal lithiasis in comparison with the standard classification (P < 0.001). Conclusions: The new classification of CD implantation enables identification of the vast majority of intra-pancreatic CDs that are correlated with a high risk of choledochal lithiasis in a single category (type 1) that is easy to identify using imaging

Epidemiological characterization of resistance and PCR typing of Shigella flexneri and Shigella sonnei strains isolated from bacillary dysentery cases in Southeast Brazil

Shigella spp are Gram-negative, anaerobic facultative, non-motile, and non-sporulated bacilli of the Enterobacteriaceae family responsible for "Shigellosis" or bacillary dysentery, an important cause of worldwide morbidity and mortality. However, despite this, there are very few epidemiological studies about this bacterium in Brazil. We studied the antibiotic resistance profiles and the clonal structure of 60 Shigella strains (30 S. flexneri and 30 S. sonnei) isolated from shigellosis cases in different cities within the metropolitan area of Campinas, State of São Paulo, Brazil. We used the following well-characterized molecular techniques: enterobacterial repetitive intergenic consensus, repetitive extragenic palindromic, and double-repetitive element-polymerase chain reaction to characterize the bacteria. Also, the antibiotic resistance of the strains was determined by the diffusion disk method. Many strains of S. flexneri and S. sonnei were found to be multi-resistant. S. flexneri strains were resistant to ampicillin in 83.3% of cases, chloramphenicol in 70.0%, streptomycin in 86.7%, sulfamethoxazole in 80.0%, and tetracycline in 80.0%, while a smaller number of strains were resistant to cephalothin (3.3%) and sulfazotrim (10.0%). S. sonnei strains were mainly resistant to sulfamethoxazole (100.0%) and tetracycline (96.7%) and, to a lesser extent, to ampicillin (6.7%) and streptomycin (26.7%). Polymerase chain reaction-based typing supported the existence of specific clones responsible for the shigellosis cases in the different cities and there was evidence of transmission between cities. This clonal structure would probably be the result of selection for virulence and resistance phenotypes. These data indicate that the human sanitary conditions of the cities investigated should be improved

Epidemiological Characterization Of Resistance And Pcr Typing Of Shigella Flexneri And Shigella Sonnei Strains Isolated From Bacillary Dysentery Cases In Southeast Brazil.

Shigella spp are Gram-negative, anaerobic facultative, non-motile, and non-sporulated bacilli of the Enterobacteriaceae family responsible for Shigellosis or bacillary dysentery, an important cause of worldwide morbidity and mortality. However, despite this, there are very few epidemiological studies about this bacterium in Brazil. We studied the antibiotic resistance profiles and the clonal structure of 60 Shigella strains (30 S. flexneri and 30 S. sonnei) isolated from shigellosis cases in different cities within the metropolitan area of Campinas, State of São Paulo, Brazil. We used the following well-characterized molecular techniques: enterobacterial repetitive intergenic consensus, repetitive extragenic palindromic, and double-repetitive element-polymerase chain reaction to characterize the bacteria. Also, the antibiotic resistance of the strains was determined by the diffusion disk method. Many strains of S. flexneri and S. sonnei were found to be multi-resistant. S. flexneri strains were resistant to ampicillin in 83.3% of cases, chloramphenicol in 70.0%, streptomycin in 86.7%, sulfamethoxazole in 80.0%, and tetracycline in 80.0%, while a smaller number of strains were resistant to cephalothin (3.3%) and sulfazotrim (10.0%). S. sonnei strains were mainly resistant to sulfamethoxazole (100.0%) and tetracycline (96.7%) and, to a lesser extent, to ampicillin (6.7%) and streptomycin (26.7%). Polymerase chain reaction-based typing supported the existence of specific clones responsible for the shigellosis cases in the different cities and there was evidence of transmission between cities. This clonal structure would probably be the result of selection for virulence and resistance phenotypes. These data indicate that the human sanitary conditions of the cities investigated should be improved.40249-5

<i>Vibrio communis</i> sp. nov., isolated from the marine animals <i>Mussismilia hispida, Phyllogorgia dilatata, Palythoa caribaeorum, Palythoa variabilis</i> and <i>Litopenaeus vannamei</i>

Eight Vibrio isolates originating from the marine corals Mussismilia hispida and Phyllogorgia dilatata and the zoanthids Palythoa caribaeorum and Palythoa variabilis in Brazil and the Pacific white shrimp (Litopenaeus vannamei) in Ecuador were studied by means of a polyphasic approach. The novel isolates formed a tight monophyletic group in the genus Vibrio and were closely related to species of the Vibrio harveyi group, to which they showed more than 99?% 16S rRNA gene sequence similarity. Analysis based on concatenated sequences of the following seven genes, 16S rRNA, gyrB, recA, rpoA, topA, pyrH and mreB (5633 bp in length), showed clear separation between the isolates and species of the V. harveyi group. Amplified fragment length polymorphism (AFLP) analysis, performed previously, revealed that a representative isolate of this group, LMG 20370, was clearly separate from known Vibrio species (it belonged to the so-called AFLP cluster A31). DNA–DNA hybridization (DDH) experiments with representative isolates and type strains of the V. harveyi species group revealed high DDH between the novel isolates (more than 74?%) and less than 70?% DDH towards type strains of related Vibrio species, proving the novel species status of the isolates. Phenotypically, the novel species belongs to the arginine dihydrolase (A)-negative, lysine decarboxylase (L)-positive and ornithine decarboxylase (O)-positive (A-/L+/O+) cluster reported previously. Most species of the V. harveyi group (i.e. Vibrio rotiferianus, V. harveyi, V. parahaemolyticus and V. alginolyticus) also belong to this A-/L+/O+ cluster. However, several phenotypic features can be used for the identification of the novel species. In contrast to its closest phylogenetic neighbours, the novel species exhibits esterase (C4) and N-acetyl-ß-glucosaminidase activities, but it does not produce acetoin, does not use citrate, a-ketoglutaric acid or propionic acid and does not ferment melibiose. The novel species can also be differentiated on the basis of the presence of the fatty acids C17?:?0, C17?:?1?8c, iso-C17?:?0 and iso-C13?:?0 and the absence of the fatty acid C18?:?0. The name Vibrio communis sp. nov. is proposed for this taxon. Strain R-40496T (=LMG 25430T =CAIM 1816T) is the type strain

Imaging of colorectal liver metastases: New developments and pending issues

Computed tomography (CT), magnetic resonance imaging (MRI), and 18-fluorideoxyglucose positron emission tomography (18 FDG-PET) are historically the most accurate imaging techniques for diagnosing liver metastases. Recently, the combination of diffusion-weighted imaging and hepatospecific contrast media, such as gadoxetic acid in MRI, have been demonstrated to have the highest diagnostic accuracy, sensitivity, and specificity for detecting liver metastases. Various recent meta-analyses have confirmed the diagnostic superiority of this combination (diffusion-weighted imaging and gadoxetic acid-enhanced MRI), especially in terms of per lesion sensitivity, as compared with CT and18 FDG-PET, even for smaller lesions ( 641 cm). However, none of the oncological guidelines have suggested the use of MRI as a first-line technique for liver metastasis detection during the staging process of oncological patients. This review analyzes the history of the principal imaging techniques for the diagnosis of liver metastases, in particular of colorectal liver metastases, focusing on the most accurate method (diffusion-weighted imaging combined with gadoxetic acid-enhanced MRI), possible reasons for the lack of its diffusion in the guidelines, and possible future scenarios

Salmonella enterica Typhimurium FljBA operon Sstability: implications regarding the origin of Salmonella enterica I 4,[5],12:i:-

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORSalmonella enterica subsp enterica serovar 4,5,12:i:- has been responsible for many recent Salmonella outbreaks worldwide. Several studies indicate that this serovar originated from S. enterica subsp enterica serovar Typhimurium, by the loss of the flagellar phase II gene (fljB) and adjacent sequences. However, at least two different clones of S. enterica 4,5,12:i:- exist that differs in the molecular events responsible for fljB deletion. The aim of this study was to test the stability of the fljBA operon responsible for the flagellar phase variation under different growth conditions in order to verify if its deletion is a frequent event that could explain the origin and dissemination of this serovar. In fact, coding sequences for transposons are present near this operon and in some strains, such as S. enterica Typhimurium LT2, the Fels-2 prophage gene is inserted near this operon. The presence of mobile DNA could confer instability to this region. In order to examine this, the cat (chloramphenicol acetyltransferase) gene was inserted adjacent to the fljBA operon so that deletions involving this genomic region could be identified. After growing S. enterica chloramphenicol-resistant strains under different conditions, more than 104 colonies were tested for the loss of chloramphenicol resistance. However, none of the colonies were sensitive to chloramphenicol. These data suggest that the origin of S. enterica serovar 4,5,12:i:- from Typhimurium by fljBA deletion is not a frequent event. The origin and dissemination of 4,5,12:i:- raise several questions about the role of flagellar phase variation in virulence.Salmonella enterica subsp enterica serovar 4,5,12:i:- has been responsible for many recent Salmonella outbreaks worldwide. Several studies indicate that this serovar originated from S. enterica subsp enterica serovar Typhimurium, by the loss of the flagel1441905719065FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR2009/15956-7; 2012/10608-3; 2012/05382-6; 2014/11280-7; 2013/11880-1308955/2012-9; 141629/2012-601P-04520-201

Transient asymptomatic pulmonary opacities and interstitial lung disease in EGFR-mutated non-small cell lung cancer treated with osimertinib

Introduction: Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) approved as first-line therapy for advanced EGFR-mutated non-small cell lung cancer (NSCLC). Some osimertinib-related interstitial lung diseases (ILDs) were shown to be transient, called transient asymptomatic pulmonary opacities (TAPO)—clinically benign pulmonary opacities that resolve despite continued osimertinib treatment—and are not associated with the clinical manifestations of typical TKI-associated ILDs. Methods: In this multicentric study, we retrospectively analyzed 92 patients with EGFR-mutated NSCLC treated with osimertinib. Computed tomography (CT) examinations were reviewed by two radiologists and TAPO were classified according to radiologic pattern. We also analyzed associations between TAPO and patients’ clinical variables and compared clinical outcomes (time to treatment failure and overall survival) for TAPO-positive and TAPO-negative groups. Results: TAPO were found in 18/92 patients (19.6%), with a median follow-up of 114 weeks. Median onset time was 16 weeks (range 6–80) and median duration time 14 weeks (range 8–37). The most common radiologic pattern was focal ground-glass opacity (54.5%). We did not find any individual clinical variable significantly associated with the onset of TAPO or significant difference in clinical outcomes between TAPO-positive and TAPO-negative groups. Conclusions: TAPO are benign pulmonary findings observed in patients treated with osimertinib. TAPO variability in terms of CT features can hinder the differential diagnosis with either osimertinib-related mild ILD or tumor progression. However, because TAPO are asymptomatic, it could be reasonable to continue therapy and verify the resolution of the CT findings at follow-up in selected cases

Levels of expression and immunogenicity of attenuated Salmonella enterica serovar typhimurium strains expressing Escherichia coli mutant heat-labile enterotoxin

The effects of heterologous gene dosage as well as Salmonella typhimurium strain variability on immune response toward both the heterologous antigen, the nontoxic mutant of the Escherichia coli heat-labile enterotoxin LTK63, and the carrier Salmonella strain have been analyzed, Effects of a single integration into the host DNA and different-copy-number episomal vectors were compared in S. typhimurium Delta cya Delta crp Delta asd strains of two different serotypes, UK-1 and SR-11, Expression of the enterotoxin in the different Salmonella isolates in vitro was found to vary considerably and, for the episomal vectors, to correlate with the plasmid copy number, LTK63-specific serum immunoglobulin G (IgG) and mucosal immunoglobulin A (IgA) antibodies were highest in mice immunized with the high-level-expression strain. High anti-LTK63 IgG and IgA titers were found to correspond to higher anti-Salmonella immunity, suggesting that LTK63 exerts an adjuvant effect on response to the carrier. Statistically significant differences in anti-LTK63 immune response were observed between groups of mice immunized with the attenuated Delta cya Delta crp UK-I and SR-II derivatives producing the antigen at the same rate, These data indicate that the same attenuation in S, typhimurium strains of different genetic backgrounds can influence significantly the immune response toward the heterologous antigen. Moreover, delivery of the LTK63 enterotoxin to the immune system by attenuated S. typhimurium strains is effective only when synthesis of the antigen is very high during the initial phase of invasion, while persistence of the S. typhimurium strain in deep tissues has only marginal influence.66122423