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1.
PLoS Comput Biol ; 20(2): e1011270, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38324613

RESUMO

CyVerse, the largest publicly-funded open-source research cyberinfrastructure for life sciences, has played a crucial role in advancing data-driven research since the 2010s. As the technology landscape evolved with the emergence of cloud computing platforms, machine learning and artificial intelligence (AI) applications, CyVerse has enabled access by providing interfaces, Software as a Service (SaaS), and cloud-native Infrastructure as Code (IaC) to leverage new technologies. CyVerse services enable researchers to integrate institutional and private computational resources, custom software, perform analyses, and publish data in accordance with open science principles. Over the past 13 years, CyVerse has registered more than 124,000 verified accounts from 160 countries and was used for over 1,600 peer-reviewed publications. Since 2011, 45,000 students and researchers have been trained to use CyVerse. The platform has been replicated and deployed in three countries outside the US, with additional private deployments on commercial clouds for US government agencies and multinational corporations. In this manuscript, we present a strategic blueprint for creating and managing SaaS cyberinfrastructure and IaC as free and open-source software.


Assuntos
Inteligência Artificial , Software , Humanos , Computação em Nuvem , Editoração
2.
J Phys Chem A ; 126(44): 8337-8347, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36300823

RESUMO

Neural network potentials are emerging as promising classical force fields that can enable long-time and large-length scale simulations at close to ab initio accuracies. They learn the underlying potential energy surface by mapping the Cartesian coordinates of atoms to system energies using elemental neural networks. To ensure invariance with respect to system translation, rotation, and atom index permutations, in the Behler-Parrinnello type of neural network potential (BP-NNP), the Cartesian coordinates of atoms are transformed into "structural fingerprints" using atom-centered symmetry functions (ACSFs). Development of an accurate BP-NNP for any chemical system critically relies on the choice of these ACSFs. In this work, we have proposed a systematic framework for the identification of an optimal set of ACSFs for any target system, which not only considers the diverse atomic environments present in the training dataset but also inter-ACSF correlations. Our method is applicable to different kinds of ACSFs and across diverse chemical systems. We demonstrate this by building accurate BP-NNPs for water and Cu2S systems.


Assuntos
Redes Neurais de Computação , Água , Água/química
3.
Postgrad Med J ; 97(1146): 250-255, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33184132

RESUMO

BACKGROUND: Complex regional pain syndrome (CRPS) is a heterogenous and poorly understood condition that can be provoked by quite minor injuries. The symptoms and signs of CRPS persist, long after the patient has recovered from the inciting event. In some cases, there is a clear association with a peripheral nerve injury. The degree of disability produced by CRPS is often out of proportion to the scale of the original insult and the condition is associated with protracted recovery times and frequent litigation. METHODS: We have performed a PubMed literature search, referenced landmark papers in the field and included a national expert in peripheral nerve injury and repair in our team of authors. RESULTS AND CONCLUSIONS: The diagnostic criteria for CRPS have changed repeatedly over the last two centuries and much of the historical literature is difficult to compare with more recent research. In this review article, we consider how our understanding of the condition has evolved and discuss its pathogenesis, its apparent heterogenicity and the various investigations and treatments available to the clinician.


Assuntos
Síndromes da Dor Regional Complexa/diagnóstico , Síndromes da Dor Regional Complexa/terapia , Amputação Cirúrgica , Anti-Inflamatórios/uso terapêutico , Anticonvulsivantes/uso terapêutico , Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Toxinas Botulínicas Tipo A/uso terapêutico , Síndromes da Dor Regional Complexa/etiologia , Gabapentina/uso terapêutico , Glucocorticoides/uso terapêutico , História do Século XX , História do Século XXI , Humanos , Fármacos Neuromusculares/uso terapêutico , Traumatismos dos Nervos Periféricos/diagnóstico , Modalidades de Fisioterapia , Fatores de Risco , Simpatectomia
4.
J Appl Clin Med Phys ; 22(7): 177-187, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34101349

RESUMO

Rigorous radiotherapy quality surveillance and comprehensive outcome assessment require electronic capture and automatic abstraction of clinical, radiation treatment planning, and delivery data. We present the design and implementation framework of an integrated data abstraction, aggregation, and storage, curation, and analytics software: the Health Information Gateway and Exchange (HINGE), which collates data for cancer patients receiving radiotherapy. The HINGE software abstracts structured DICOM-RT data from the treatment planning system (TPS), treatment data from the treatment management system (TMS), and clinical data from the electronic health records (EHRs). HINGE software has disease site-specific "Smart" templates that facilitate the entry of relevant clinical information by physicians and clinical staff in a discrete manner as part of the routine clinical documentation. Radiotherapy data abstracted from these disparate sources and the smart templates are processed for quality and outcome assessment. The predictive data analyses are done on using well-defined clinical and dosimetry quality measures defined by disease site experts in radiation oncology. HINGE application software connects seamlessly to the local IT/medical infrastructure via interfaces and cloud services and performs data extraction and aggregation functions without human intervention. It provides tools to assess variations in radiation oncology practices and outcomes and determines gaps in radiotherapy quality delivered by each provider.


Assuntos
Neoplasias , Radioterapia (Especialidade) , Documentação , Humanos , Neoplasias/radioterapia , Planejamento da Radioterapia Assistida por Computador , Software
5.
Acta Orthop Belg ; 87(4): 761-764, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35172445

RESUMO

Hindfoot deformities are often surgically corrected with calcaneal osteotomy. These are increasingly performed via a minimally invasive approach. Identifying a neurovascular "safe zone" for this approach is important in reducing iatrogenic injury. We aimed to identify a safe zone for minimally invasive calcaneal osteotomy without neurovascular injury. Three individuals independently assessed 100 con- secutive magnetic resonance imaging ankle studies. The distance of the medial neurovascular bundle from the level of the centre of the Achilles tendon insertion was measured. The points measured were centralised in three planes (axial, sagittal and coronal). The three sets of observations were statistically analysed with confidence intervals and intraclass correlation coefficient was calculated. The mean distance measured by the three observers were 22.91 mm (range 18.2-28.5 mm); 22.81 mm (range 18.7-26.7 mm); and 23.41 mm (range 19.2- 28.4 mm); overall mean 23.0 mm. The mean inter- observer variation was 1.1 mm. 95% confidence interval for observer 1 ranges from 22.45-23.25 mm, observer 2 ranges from 22.52-23.1 mm and observer 3 ranges from 22.97-23.65 mm. Overall 95% confidence interval ranges from 22.8-23.2 mm. Intraclass correlation coefficient for inter-observer reliability is 0.7, indicating strong agreement between the observers. This radiological study suggests an anatomical "safe zone" for minimally invasive medial calcaneal osteotomy is at least 18 mm (mean: 23 mm) from the level of insertion of the Achilles tendon. Individual variation between patients must be taken in to consideration during preoperative planning.


Assuntos
Tendão do Calcâneo , Calcâneo , Tendão do Calcâneo/diagnóstico por imagem , Tendão do Calcâneo/cirurgia , Calcâneo/diagnóstico por imagem , Calcâneo/cirurgia , Humanos , Imageamento por Ressonância Magnética , Osteotomia/métodos , Reprodutibilidade dos Testes
6.
Phys Chem Chem Phys ; 22(7): 4177-4192, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32040116

RESUMO

Solvent extraction (SX), wherein two immiscible liquids, one containing the extractant molecules and the other containing the solute to be extracted are brought in contact to effect the phase transfer of the solute, underpins metal extraction and recovery processes. The interfacial region is of utmost importance in the SX process, since besides thermodynamics, the physical and chemical heterogeneity at the interface governs the kinetics of the process. Yet, a fundamental understanding of this heterogeneity and its implications for the extraction mechanism are currently lacking. We use molecular dynamics (MD) simulations to study the liquid-liquid interface under conditions relevant to the SX of Rare Earth Elements (REEs) by a phosphoric acid ligand. Simulations revealed that the extractant molecules and varying amounts of acid and metal ions partitioned to the interface. The presence of these species had a significant effect on the interfacial thickness, hydrogen bond life times and orientations of the water molecules at the interface. Deprotonation of the ligands was essential for the adsorption of the metal ions at the interface, with these ions forming a number of different complexes at the interface involving one to three extractant molecules and four to eight water molecules. Although the interface itself was rough, no obvious 'finger-like' water protrusions penetrating the organic phase were seen in our simulations. While the results of our work help us gain fundamental insights into the sequence of events leading to the formation of a variety of interfacial complexes, they also emphasize the need to carry out a more detailed atomic level study to understand the full mechanism of extraction of REEs from the aqueous to organic phases by phosphoric acid ligands.

7.
Phys Chem Chem Phys ; 22(15): 7719-7727, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32215419

RESUMO

Hydration of surface ions gives rise to structural heterogeneity and variable exchange kinetics of water at complex mineral-water interfaces. Here, we employ ab initio molecular dynamics (AIMD) simulations and water adsorption calorimetry to examine the aqueous interfaces of xenotime, a phosphate mineral that contains predominantly Y3+ and heavy rare earth elements. Consistent with natural crystal morphology, xenotime is predicted to have a tetragonal prismatic shape, dominated by the {100} surface. Hydration of this surface induces multilayer interfacial water structures with distinct OH orientations, which agrees with recent crystal truncation rod measurements. The exchange kinetics between two adjacent water layers exhibits a wide range of underlying timescales (5-180 picoseconds), dictated by ion-water electrostatics. Adsorption of a bidentate hydroxamate ligand reveals that {100} xenotime surface can only accommodate monodentate coordination with water exchange kinetics strongly depending on specific ligand orientation, prompting us to reconsider traditional strategies for selective separation of rare-earth minerals.

8.
Phys Chem Chem Phys ; 21(35): 19423-19436, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31460545

RESUMO

In the recent past, there has been proliferation in high-throughput density functional theory and data-driven explorations of materials motivated by a need to reduce physical testing and costly computations for materials discovery. This has, in conjunction with the development of open-access materials property databases, encouraged accelerated and more streamlined discovery and screening of technologically relevant materials. In this work, we report our results on the screening and DFT studies of one such class of materials, i.e. ABX3 inorganic halide perovskites (A, B and X representing the monovalent, divalent and halide ions respectively) using a coupled machine-learning (ML) and density functional theory (DFT) approach. Utilizing the support vector machine algorithm, we predict the formability of 454 inorganic halide compounds in the perovskite phase. Compounds with a formation probability P≥ 0.8 are further checked for thermodynamic stability in at least one of these three open materials databases - Materials Project (MP), Automatic FLOW for Materials Discovery (AFLOW) and Open Quantum Materials Database (OQMD). The shortlisted candidate perovskites are then considered for DFT computations. Taking input geometries from MP's structure predictor, the optimized lattice parameters and computed band gaps (BG) for all screened compounds are compared with predictions across all databases. Subsequently, detailed studies on low index surfaces are presented for two halide perovksites - RbSnCl3 and RbSnBr3- having band-gaps in the favourable range for photovoltaics (PV). Different possible (100), (110) and (111) surface terminations are investigated for each of these compositions and the atomic relaxations, surface energies and electronic band structures are reported for each termination. To the best of our knowledge, no surface studies have been reported in the literature for any of the halide perovskites present in our database. These studies, therefore, are an important step towards gaining a fundamental understanding of the interfacial properties of perovskites, which can help facilitate further breakthroughs in the PV technology.

9.
Inorg Chem ; 56(3): 1722-1733, 2017 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-28116904

RESUMO

Potentiometric and spectroscopic techniques were combined with DFT calculations to probe the coordination environment and determine thermodynamic features of trivalent f-element complexation by N-hydroxyethyl-diethylenetriamine-N,N',N″,N″-tetraacetic acid, HEDTTA. Ligand protonation constants and lanthanide stability constants were determined using potentiometry. Five protonation constants were accessible in I = 2.0 M (H+/Na+)ClO4. UV-vis spectroscopy was used to determine stability constants for Nd3+ and Am3+ complexation with HEDTTA. Luminescence spectroscopy indicates two water molecules in the inner coordination sphere of the Eu/HEDTTA complex, suggesting HEDTTA is heptadentate. Luminescence data was supported by DFT calculations, which demonstrate that substitution of the acetate pendant arm by a N-hydroxyethyl group weakens the metal-nitrogen bond. This bond elongation is reflected in HEDTTA's ability to differentiate trivalent actinides from trivalent lanthanides. The trans-lanthanide Ln/HEDTTA complex stability trend is analogous to Ln/DTPA complexation; however, the loss of one chelate ring resulting from structural substitution weakens the complexation by ∼3 orders of magnitude. Successful separation of trivalent americium from trivalent lanthanides was demonstrated when HEDTTA was utilized as aqueous holdback complexant in a liquid-liquid system. Time-dependent extraction studies for HEDTTA were compared to diethylenetriamine-N,N,N',N″,N″-pentaacetic acid (DTPA) and N-hydroxyethyl-ethylenediamine-N,N',N'-triacetic acid (HEDTA). The results indicate substantially enhanced phase-transfer kinetic rates for mixtures containing HEDTTA.

10.
Phys Chem Chem Phys ; 19(11): 7820-7832, 2017 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-28262886

RESUMO

Bastnäsite, a fluoro-carbonate mineral, is the single largest mineral source of light rare earth elements (REE), La, Ce and Nd. Enhancing the efficiency of separation of the mineral from gangue through froth flotation is the first step towards meeting an ever increasing demand for REE. To design and evaluate collector molecules that selectively bind to bastnäsite, a fundamental understanding of the structure and surface properties of bastnäsite is essential. In our earlier work (J. Phys. Chem. C, 2016, 120, 16767), we carried out an extensive study of the structure, surface stability and water adsorption energies of La-bastnäsite. In this work, we make a comparative study of the surface properties of Ce-bastnäsite, La-bastnäsite, and calcite using a combination of density functional theory (DFT) and water adsorption calorimetry. Spin polarized DFT+U calculations show that the exchange interaction between the electrons in Ce 4f orbitals is negligible and that these orbitals do not participate in bonding with the oxygen atom of the adsorbed water molecule. In agreement with calorimetry, DFT calculations predict larger surface energies and stronger water adsorption energies on Ce-bastnäsite than on La-bastnäsite. The order of stabilities for stoichiometric surfaces is as follows: [101[combining macron]0] > [101[combining macron]1] > [101[combining macron]2] > [0001] > [112[combining macron]2] > [101[combining macron]4] and the most favorable adsorption sites for water molecules are the same as for La-bastnäsite. In agreement with water adsorption calorimetry, at low coverage water molecules are strongly stabilized via coordination to the surface Ce3+ ions, whereas at higher coverage they are adsorbed less strongly via hydrogen bonding interaction with the surface anions. Due to similar water adsorption energies on bastnäsite [101[combining macron]1] and calcite [101[combining macron]4] surfaces, the design of collector molecules that selectively bind to bastnäsite over calcite must exploit the structural differences in the predominantly exposed facets of these minerals.

11.
J Phys Chem A ; 119(4): 571-80, 2015 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-25562718

RESUMO

In this article, we report the development of a ReaxFF reactive potential that can accurately describe the chemistry and dynamics of carbon condensed phases. Density functional theory (DFT)-based calculations were performed to obtain the equation of state for graphite and diamond and the formation energies of defects in graphene and amorphous phases from fullerenes. The DFT data were used to reparametrize ReaxFFCHO, resulting in a new potential called ReaxFFC-2013. ReaxFFC-2013 accurately predicts the atomization energy of graphite and closely reproduces the DFT-based energy difference between graphite and diamond, and the barrier for transition from graphite to diamond. ReaxFFC-2013 also accurately predicts the DFT-based energy barrier for Stone-Wales transformation in a C60(Ih) fullerene through the concerted rotation of a C2 unit. Later, MD simulations of a C180 fullerene using ReaxFFC-2013 suggested that the thermal fragmentation of these giant fullerenes is an exponential function of time. An Arrhenius-type equation was fit to the decay rate, giving an activation energy of 7.66 eV for the loss of carbon atoms from the fullerene. Although the decay of the molecule occurs primarily via the loss of C2 units, we observed that, with an increase in temperature, the probability of loss of larger fragments increases. The ReaxFFC-2013 potential developed in this work, and the results obtained on fullerene fragmentation, provide an important step toward the full computational chemical modeling of coal pyrolysis, soot incandescence, high temperature erosion of graphitic rocket nozzles, and ablation of carbon-based spacecraft materials during atmospheric reentry.

12.
J Clin Ultrasound ; 43(7): 417-20, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25379882

RESUMO

PURPOSE: Patients often have difficulty performing the various movements required for ideal positioning to enable accurate sonographic (US) assessment of the shoulder; this may result from pain and or unclear oral instructions. We performed this study to ascertain whether the use of a poster depicting the positions required during the examination would decrease scanning time and hence improve the overall efficiency of shoulder US. METHODS: We retrospectively compared results from 50 consecutive patients who underwent US examination without (group 1) and 50 with (group 2) the use of an illustrative poster produced by the European Society of Musculoskeletal Radiology. The difference in mean scanning time between the two groups was analyzed with Student's two-tailed t test. RESULTS: There was a statistically significant difference in scanning time between the two groups (group 1: 3 minutes and 5 seconds versus group 2: 2 minutes and 9 seconds; p < 0.0001). The patients in group 2, especially those who had hearing difficulty, found the poster useful. CONCLUSIONS: The use of a poster illustrating positioning of the shoulder during an US examination is an effective way to improve patient compliance and significantly decreases scanning time.


Assuntos
Posicionamento do Paciente/métodos , Pôsteres como Assunto , Articulação do Ombro/diagnóstico por imagem , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente/estatística & dados numéricos , Estudos Retrospectivos , Ultrassonografia , Adulto Jovem
13.
J Phys Chem A ; 118(29): 5520-8, 2014 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-24960065

RESUMO

We present a new DFTB-p3b density functional tight binding model for hydrogen at extremely high pressures and temperatures, which includes a polarizable basis set (p) and a three-body environmentally dependent repulsive potential (3b). We find that use of an extended basis set is necessary under dissociated liquid conditions to account for the substantial p-orbital character of the electronic states around the Fermi energy. The repulsive energy is determined through comparison to cold curve pressures computed from density functional theory (DFT) for the hexagonal close-packed solid, as well as pressures from thermally equilibrated DFT-MD simulations of the liquid phase. In particular, we observe improved agreement in our DFTB-p3b model with previous theoretical and experimental results for the shock Hugoniot of hydrogen up to 100 GPa and 25000 K, compared to a standard DFTB model using pairwise interactions and an s-orbital basis set, only. The DFTB-p3b approach discussed here provides a general method to extend the DFTB method for a wide variety of materials over a significantly larger range of thermodynamic conditions than previously possible.


Assuntos
Hidrogênio/química , Simulação de Dinâmica Molecular , Teoria Quântica , Termodinâmica , Sítios de Ligação , Pressão , Temperatura
14.
Bone Joint J ; 106-B(2): 158-165, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38425310

RESUMO

Aims: Periprosthetic fractures (PPFs) around the knee are challenging injuries. This study aims to describe the characteristics of knee PPFs and the impact of patient demographics, fracture types, and management modalities on in-hospital mortality. Methods: Using a multicentre study design, independent of registry data, we included adult patients sustaining a PPF around a knee arthroplasty between 1 January 2010 and 31 December 2019. Univariate, then multivariable, logistic regression analyses were performed to study the impact of patient, fracture, and treatment on mortality. Results: Out of a total of 1,667 patients in the PPF study database, 420 patients were included. The in-hospital mortality rate was 6.4%. Multivariable analyses suggested that American Society of Anesthesiologists (ASA) grade, history of peripheral vascular disease (PVD), history of rheumatic disease, fracture around a loose implant, and cerebrovascular accident (CVA) during hospital stay were each independently associated with mortality. Each point increase in ASA grade independently correlated with a four-fold greater mortality risk (odds ratio (OR) 4.1 (95% confidence interval (CI) 1.19 to 14.06); p = 0.026). Patients with PVD have a nine-fold increase in mortality risk (OR 9.1 (95% CI 1.25 to 66.47); p = 0.030) and patients with rheumatic disease have a 6.8-fold increase in mortality risk (OR 6.8 (95% CI 1.32 to 34.68); p = 0.022). Patients with a fracture around a loose implant (Unified Classification System (UCS) B2) have a 20-fold increase in mortality, compared to UCS A1 (OR 20.9 (95% CI 1.61 to 271.38); p = 0.020). Mode of management was not a significant predictor of mortality. Patients managed with revision arthroplasty had a significantly longer length of stay (median 16 days; p = 0.029) and higher rates of return to theatre, compared to patients treated nonoperatively or with fixation. Conclusion: The mortality rate in PPFs around the knee is similar to that for native distal femur and neck of femur fragility fractures. Patients with certain modifiable risk factors should be optimized. A national PPF database and standardized management guidelines are currently required to understand these complex injuries and to improve patient outcomes.


Assuntos
Artroplastia do Joelho , Fraturas do Fêmur , Fraturas Periprotéticas , Doenças Reumáticas , Adulto , Humanos , Fraturas Periprotéticas/etiologia , Articulação do Joelho/cirurgia , Joelho/cirurgia , Artroplastia do Joelho/efeitos adversos , Fraturas do Fêmur/cirurgia , Doenças Reumáticas/etiologia , Doenças Reumáticas/cirurgia , Estudos Retrospectivos , Reoperação
15.
J Phys Chem A ; 117(13): 2692-703, 2013 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-23438070

RESUMO

Large scale molecular dynamics (MD) simulations are performed to study the oxidation of highly oriented pyrolytic graphite (HOPG) by hyperthermal atomic oxygen beam (5 eV). Simulations are performed using the ReaxFF classical reactive force field. We present here additional evidence that this method accurately reproduces ab initio derived energies relevant to HOPG oxidation. HOPG is modeled as multilayer graphene and etch-pit formation and evolution is directly simulated through a large number of sequential atomic oxygen collisions. The simulations predict that an oxygen coverage is first established that acts as a precursor to carbon-removal reactions, which ultimately etch wide but shallow pits, as observed in experiments. In quantitative agreement with experiment, the simulations predict the most abundant product species to be O2 (via recombination reactions), followed by CO2, with CO as the least abundant product species. Although recombination occurs all over the graphene sheet, the carbon-removal reactions occur only about the edges of the etch pit. Through isolated defect analysis on small graphene models as well as trajectory analysis performed directly on the predicted etch pit, the activation energies for the dominant reaction mechanisms leading to O2, CO2, and CO product species are determined to be 0.3, 0.52, and 0.67 eV, respectively. Overall, the qualitative and quantitative agreement between MD simulation and experiment is very promising. Thus, the MD simulation approach and C/H/O ReaxFF parametrization may be useful for simulating high-temperature gas interactions with graphitic materials where the microstructure is more complex than HOPG.

16.
Artigo em Inglês | MEDLINE | ID: mdl-38044859

RESUMO

Multicomponent alloys are promising catalysts for diverse chemical conversions, owing to the ability to tune their vast compositional space to maximize catalytic activity and product selectivity. However, elemental segregation, whereby the surface or grain boundaries of the material are enriched in a few elements, is a physically observed phenomenon in such alloys. Such segregation alters not only the composition but also the kinds of catalytically active sites present at the surface. Thus, elemental segregation, which can be achieved via various processing techniques, can be used as an additional knob in searching for alloy compositions that are both active and selective for a target chemical conversion. We demonstrate this using molecular simulations, machine learning, and Bayesian optimization to search for both random solid solution and "segregated" AgAuCuPdPt alloy compositions that are potentially active and selective for CO reduction reaction (CORR). Finally, we validate our findings by computing the reaction-free energy landscape for the CORR on the optimal alloy compositions via density functional theory calculations.

17.
Injury ; 54(12): 111152, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37939635

RESUMO

INTRODUCTION: Periprosthetic fractures (PPFs) around the hip joint are increasing in prevalence. In this collaborative study, we aimed to investigate the impact of patient demographics, fracture characteristics, and modes of management on in-hospital mortality of PPFs involving the hip. METHODS: Using a multi-centre cohort study design, we retrospectively identified adults presenting with a PPF around the hip over a 10-year period. Univariate and multivariable logistic regression analyses were performed to study the independent correlation between patient, fracture, and treatment factors on mortality. RESULTS: A total of 1,109 patients were included. The in-hospital mortality rate was 5.3%. Multivariable analyses suggested that age, male sex, abbreviated mental test score (AMTS), pneumonia, renal failure, history of peripheral vascular disease (PVD) and deep surgical site infection were each independently associated with mortality. Each yearly increase in age independently correlates with a 7% increase in mortality (OR 1.07, p=0.019). The odds of mortality was 2.99 times higher for patients diagnosed with pneumonia during their hospital stay [OR 2.99 (95% CI 1.07-8.37) p=0.037], and 7.25 times higher for patients that developed renal failure during their stay [OR 7.25 (95% CI 1.85-28.47) p=0.005]. Patients with history of PVD have a six-fold greater mortality risk (OR 6.06, p=0.003). Mode of treatment was not a significant predictor of mortality. CONCLUSION: The in-hospital mortality rate of PPFs around the hip exceeds 5%. The fracture subtype and mode of management are not independent predictors of mortality, while patient factors such as age, AMTS, history of PVD, pneumonia, and renal failure can independently predict mortality. Peri-operative optimisation of modifiable risk factors such as lung and kidney function in patients with PPFs around the hip during their hospital stay is of utmost importance.


Assuntos
Artroplastia de Quadril , Fraturas do Quadril , Doenças Vasculares Periféricas , Fraturas Periprotéticas , Pneumonia , Insuficiência Renal , Adulto , Humanos , Masculino , Estudos Retrospectivos , Estudos de Coortes , Artroplastia de Quadril/efeitos adversos , Doenças Vasculares Periféricas/cirurgia , Reoperação
18.
J Acoust Soc Am ; 131(3): EL262-7, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22423818

RESUMO

Codebook-based single-microphone noise suppressors, which exploit prior knowledge about speech and noise statistics, provide better performance in nonstationary noise. However, as the enhancement involves a joint optimization over speech and noise codebooks, this results in high computational complexity. A codebook-based method is proposed that uses a reference signal observed by a bone-conduction microphone, and a mapping between air- and bone-conduction codebook entries generated during an offline training phase. A smaller subset of air-conducted speech codebook entries that accurately models the clean speech signal is selected using this reference signal. Experiments support the expected improvement in performance at low computational complexity.


Assuntos
Condução Óssea/fisiologia , Inteligibilidade da Fala/fisiologia , Percepção da Fala/fisiologia , Humanos , Modelos Teóricos , Ruído , Valores de Referência , Razão Sinal-Ruído , Acústica da Fala
19.
J Acoust Soc Am ; 131(4): EL348-53, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22502492

RESUMO

Reliable presence detection is a requirement in energy-efficient occupancy-adaptive indoor lighting systems. A system of multiple ultrasonic sensors is considered for presence detection, and the performance gain from optimum fusion is studied. Two cases are considered wherein an individual sensor determines presence based on (i) local detection by processing echoes at its receiver, and (ii) the optimum Chair-Varshney fusion rule using multiple sensor detection results. The performance gains of using optimum fusion over local detection are characterized under different sensor system configurations and it is shown that improved detection sensitivity is obtained over a larger detection coverage region.

20.
J Acoust Soc Am ; 132(2): EL161-7, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22894316

RESUMO

Although single-microphone noise reduction methods perform well in stationary noise environments, their performance in non-stationary conditions remains unsatisfactory. Use of prior knowledge about speech and noise power spectral densities in the form of trained codebooks has been previously shown to address this limitation. While it is possible to use trained speech codebooks in a practical system, the variety of noise types encountered in practice makes the use of trained noise codebooks less practical. This letter presents a method that uses a generic noise codebook for speech enhancement that can be generated on-the-fly and provides good performance.


Assuntos
Acústica , Algoritmos , Ruído dos Transportes/efeitos adversos , Mascaramento Perceptivo , Inteligibilidade da Fala , Percepção da Fala , Estimulação Acústica , Acústica/instrumentação , Audiometria da Fala , Humanos , Processamento de Sinais Assistido por Computador , Espectrografia do Som , Fatores de Tempo , Transdutores
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