207 research outputs found

    Efecto del campo el?ctrico en la estructura cristalina de cer?micas submicroestructuradas DE (1-X)(Bi0.5Na0.5)TiO3- X BaTiO3 con composici?n pr?xima a la frontera morfotr?pica

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    --El sistema (1-x)(Bi0.5Na0.5)TiO3 - x BaTiO3 (BNBT100x) presenta una frontera morfotr?pica [1] (MPB) por lo que se presenta como posible material piezoel?ctrico "lead-free". Muy recientemente se han puesto de manifiesto peculiaridades estructurales de este sistema cerca de la MPB. La naturaleza y el rol de ordenamientos at?micos locales diferentes del orden global y la posibilidad de simetr?as inferiores a la rombo?drica son temas de actualidad. Exploramos aqu? el gran potencial de la difracci?n en alta resoluci?n de radiaci?n sincrotr?nica y el ajuste por Rietveld de los difractogramas de alta resoluci?n completos [2], que permite una mejor caracterizaci?n de las fases presentes que en los habituales an?lisis de grupos de picos aislados. Se determina el efecto del campo el?ctrico aplicado en cer?micas submicro- estructuradas [3] de composiciones BNBT4 y BNBT6 obtenidas a partir de precursores nanom?tricos preparados mediante autocombusti?n de sol-gel. Los experimentos de difracci?n se desarrollaron en el sincrotr?n de Stanford (USA) con radiaci?n de 12 keV. Para todas las muestras analizadas se consider? el difractograma completo para un recorrido del vector de dispersi?n Q entre 0 y 6.4?-1. En todos los casos investigados, se esclareci? la ocurrencia de las fases tetragonal P4mm, rombo?drica R3c y/o monocl?nica Cc. Se dan resultados cuantitativos de ocurrencia, concentraciones relativas, forma y tama?o de part?culas y orientaciones preferente

    Antebrachial microvascular flap for reconstruction of the pelvic limb: case report

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    Complex defects in the soft tissues of the foot and ankle caused by high-energy trauma, infection, cancer or diabetes require rapid and effective treatment which decreases the risk of infection, bone healing time, hospital stay and number total of surgical approaches. Authors report a clinical case of a 23-year-old female patient who suffers high-energy trauma due to a motorcycle accident which causes exposure of the distal third of the tibia, loss of the tibial joint face, and loss of tissue throughout the region of the malleolus medial of the right pelvic extremity. Tissue transfer to the pelvic limb is performed using left contralateral radial antebrachial free flap as donor area. This case report aims to emphasize the key aspects of the high energy trauma approach by using microvascular flaps, as well as the satisfactory evolution of the patient that directly affects the prognosis for life and function

    Chiral recognition with a benzofuran receptor that mimics an oxyanion hole

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    A new chiral benzofuran receptor has been synthesized and its properties in the association of amino acid derivatives have been studied. X-ray structures were obtained and these corroborate the presence of an oxyanion-hole motif in these structures

    Incidence, risk factors, and effect on allograft survival of glomerulonephritis post-transplantation in a United Kingdom population: cohort study

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    BACKGROUND: Post-transplant glomerulonephritis (PTGN) has been associated with inferior long-term allograft survival, and its incidence varies widely in the literature. METHODS: This is a cohort study of 7,623 patients transplanted between 2005 and 2016 at four major transplant UK centres. The diagnosis of glomerulonephritis (GN) in the allograft was extracted from histology reports aided by the use of text-mining software. The incidence of the four most common GN post-transplantation was calculated, and the risk factors for disease and allograft outcomes were analyzed. RESULTS: In total, 214 patients (2.8%) presented with PTGN. IgA nephropathy (IgAN), focal segmental glomerulosclerosis (FSGS), membranous nephropathy (MN), and membranoproliferative/mesangiocapillary GN (MPGN/MCGN) were the four most common forms of post-transplant GN. Living donation, HLA DR match, mixed race, and other ethnic minority groups were associated with an increased risk of developing a PTGN. Patients with PTGN showed a similar allograft survival to those without in the first 8 years of post-transplantation, but the results suggest that they do less well after that timepoint. IgAN was associated with the best allograft survival and FSGS with the worst allograft survival. CONCLUSIONS: PTGN has an important impact on long-term allograft survival. Significant challenges can be encountered when attempting to analyze large-scale data involving unstructured or complex data points, and the use of computational analysis can assist

    Longitudinal outcomes of obeticholic acid therapy in ursodiol-nonresponsive primary biliary cholangitis: Stratifying the impact of add-on fibrates in real-world practice

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    Background Suboptimal response to ursodeoxycholic acid occurs in 40% of primary biliary cholangitis (PBC) patients, affecting survival. Achieving a deep response (normalisation of alkaline phosphatase [ALP] and bilirubin ≀0.6 upper limit of normal) improves survival. Yet, the long-term effectiveness of second-line treatments remains uncertain. Aims To evaluate the long-term effectiveness of obeticholic acid (OCA) ± fibrates. Focusing on biochemical response (ALP ≀1.67 times the upper limit of normal, with a decrease of at least 15% from baseline and normal bilirubin levels), normalisation of ALP, deep response and biochemical remission (deep response plus aminotransferase normalisation). Methods We conducted a longitudinal, observational, multicentre study involving ursodeoxyccholic acid non-responsive PBC patients (Paris-II criteria) from Spain and Portugal who received OCA ± fibrates. Results Of 255 patients, median follow-up was 35.1 months (IQR: 20.2–53). The biochemical response in the whole cohort was 47.2%, 61.4% and 68.6% at 12, 24 and 36 months. GLOBE-PBC and 5-year UK-PBC scores improved (p < 0.001). Triple therapy (ursodeoxycholic acid plus OCA plus fibrates) had significantly higher response rates than dual therapy (p = 0.001), including ALP normalisation, deep response and biochemical remission (p < 0.001). In multivariate analysis, triple therapy remained independently associated with biochemical response (p = 0.024), alkaline phosphatase normalisation, deep response and biochemical remission (p < 0.001). Adverse effects occurred in 41.2% of cases, leading to 18.8% discontinuing OCA. Out of 55 patients with cirrhosis, 12 developed decompensation. All with baseline portal hypertension. Conclusion Triple therapy was superior in achieving therapeutic goals in UDCA-nonresponsive PBC. Decompensation was linked to pre-existing portal hypertension

    Effectiveness and safety of first-generation protease inhibitors in clinical practice: Hepatitis C virus patients with advanced fibrosis

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    AIM: To evaluates the effectiveness and safety of the first generation, NS3/4A protease inhibitors (PIs) in clinical practice against chronic C virus, especially in patients with advanced fibrosis. METHODS: Prospective study and non-experimental analysis of a multicentre cohort of 38 Spanish hospitals that includes patients with chronic hepatitis C genotype 1, treatment-naišve (TN) or treatment-experienced (TE), who underwent triple therapy with the first generation NS3/4A protease inhibitors, boceprevir (BOC) and telaprevir (TVR), in combination with pegylated interferon and ribavirin. The patients were treatment in routine practice settings. Data on the study population and on adverse clinical and virologic effects were compiled during the treatment period and during follow up. RESULTS: One thousand and fifty seven patients were included, 405 (38%) were treated with BOC and 652 (62%) with TVR. Of this total, 30% (n = 319) were TN and the remaining were TE: 28% (n = 298) relapsers, 12% (n = 123) partial responders (PR), 25% (n = 260) null-responders (NR) and for 5% (n = 57) with prior response unknown. The rate of sustained virologic response (SVR) by intention-to-treatment (ITT) was greater in those treated with TVR (65%) than in those treated with BOC (52%) (P < 0.0001), whereas by modified intention-to-treatment (mITT) no were found significant differences. By degree of fibrosis, 56% of patients were F4 and the highest SVR rates were recorded in the non-F4 patients, both TN and TE. In the analysis by groups, the TN patients treated with TVR by ITT showed a higher SVR (P = 0.005). However, by mITT there were no significant differences between BOC and TVR. In the multivariate analysis by mITT, the significant SVR factors were relapsers, IL28B CC and non-F4; the type of treatment (BOC or TVR) was not significant. The lowest SVR values were presented by the F4-NR patients, treated with BOC (46%) or with TVR (45%). 28% of the patients interrupted the treatment, mainly by non-viral response (51%): this outcome was more frequent in the TE than in the TN patients (57% vs 40%, P = 0.01). With respect to severe haematological disorders, neutropaenia was more likely to affect the patients treated with BOC (33% vs 20%, P = 0.0001), and thrombocytopaenia and anaemia, the F4 patients (P = 0.000, P = 0.025, respectively). CONCLUSION: In a real clinical practice setting with a high proportion of patients with advanced fibrosis, effectiveness of first-generation PIs was high except for NR patients, with similar SVR rates being achieved by BOC and TVR

    Structural diversity in alkali metal and alkali metal magnesiate chemistry of the bulky 2,6-diisopropyl-N-(trimethylsilyl)anilino ligand

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    Bulky amido ligands are precious in s-block chemistry since they can implant complementary strong basic and weak nucleophilic properties within compounds. Recent work has shown the pivotal importance of the base structure with enhancement of basicity and extraordinary regioselectivities possible for cyclic alkali metal magnesiates containing mixed n-butyl/amido ligand sets. This work advances alkali metal and alkali metal magnesiate chemistry of the bulky aryl-silyl amido ligand [N(SiMe3)(Dipp)] (Dipp = 2,6-iPr2-C6H3). Infinite chain structures of the parent sodium and potassium amides are disclosed, adding to the few known crystallographically characterised unsolvated s-block metal amides. Solvation by PMDETA or TMEDA gives molecular variants of the lithium and sodium amides; whereas for potassium, PMDETA gives a molecular structure but TMEDA affords a novel, hemi-solvated infinite chain. Crystal structures of the first magnesiate examples of this amide in [MMg{N(SiMe3)(Dipp)}2(ÎŒ-nBu)]∞ (M = Na or K), are also revealed though these breakdown to their homometallic components in donor solvent as revealed through NMR and DOSY studies

    Developments and applications of the OPTIMADE API for materials discovery, design, and data exchange

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    The Open Databases Integration for Materials Design (OPTIMADE) application programming interface (API) empowers users with holistic access to a growing federation of databases, enhancing the accessibility and discoverability of materials and chemical data. Since the first release of the OPTIMADE specification (v1.0), the API has undergone significant development, leading to the upcoming v1.2 release, and has underpinned multiple scientific studies. In this work, we highlight the latest features of the API format, accompanying software tools, and provide an update on the implementation of OPTIMADE in contributing materials databases. We end by providing several use cases that demonstrate the utility of the OPTIMADE API in materials research that continue to drive its ongoing development
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