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1.
Phys Chem Chem Phys ; 26(26): 18041-18047, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-38895773

RESUMO

Nanostructured thermoelectric materials ideally reduce lattice thermal conductivity without harming the electrical properties. Thus, to truly improve the thermoelectric performance, the quality factor, which is proportional to the weighted mobility divided by the lattice thermal conductivity of the material, must be improved. Precipitates of In2Te3 form in the state-of-the-art Bi2Te3 with crystallographic alignment to the Bi2Te3 structure. Like epitaxy in films, this can be called endotaxy in solids. This natural epitaxy in a 3-dimensional solid is ideally situated to scatter phonons but produces minimal electronic scattering and, therefore, maintains high mobility. Here, we study the effects of In-alloying in Bi2Te3 at high In concentrations (about 4 at%), enough to produce the endotaxial microstructure. It is found that such concentrations of indium in Bi2Te3 significantly alter the electronic structure, reducing the effective mass and weighted mobility so significantly as to effectively destroy the thermoelectric properties even though the lattice thermal conductivity is successfully reduced.

2.
Int Orthop ; 47(9): 2337-2345, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37170027

RESUMO

PURPOSE: Pavlik harness treatment is the most common treatment in newborns diagnosed with developmental dysplasia of the hip (DDH). The success rates and predictors for failure have been debated over the last decade. In this study, we explored our treatment failure rate and potential prognostic factors that could predict the failure of Pavlik harness (PH) treatment in patients with DDH. METHODS: Two hundred and sixty-five patients were treated with PH based on the Graf hip types of classification. Age, gender, first born status, family history, foot deformity, plagiocephaly, breech presentation, hip abduction, hip stability, Graf hip type, Galeazzi sign, bilateralism, and femoral nerve palsy were tested as predictors for failure in multivariate logistic regression mode. Success and failure were determined by the normalization of the hip based on the Graf hip classification. RESULTS: The failure rate of patients treated with Pavlik harness was 16.6% which is within the reported range of failure rate. The mean age of patients who were successfully treated was 6.73 weeks in comparison to 8.84 weeks for those who failed. Age, plagiocephaly, hip instability, Graf classification, and the development of femoral nerve palsy were found to be predictors for failure of PH treatment upon univariate analysis only. However, only the presence of Galeazzi sign, hip instability, high grades of Graf hip classification, and the development of femoral nerve palsy proved to be independent predictors for failed PH treatment upon multivariate logistic regression analysis. CONCLUSIONS: Pavlik harness treatment is a successful treatment with an average success of 83.4%. Several independent predictors for failure of PH treatment have been identified. These include a positive Galeazzi sign, a frankly dislocated hip, Graf types III and IV, and the development of femoral nerve palsy.


Assuntos
Displasia do Desenvolvimento do Quadril , Luxação Congênita de Quadril , Humanos , Lactente , Recém-Nascido , Luxação Congênita de Quadril/diagnóstico por imagem , Luxação Congênita de Quadril/terapia , Aparelhos Ortopédicos , Estudos Retrospectivos , Prognóstico , Resultado do Tratamento , Paralisia , Ultrassonografia
3.
J Am Chem Soc ; 135(2): 726-32, 2013 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-23256607

RESUMO

Inspired by the promising thermoelectric properties of chalcopyrite-like quaternary chalcogenides, here we describe the synthesis and characterization of the solid solution Cu(2)Zn(1-x)Fe(x)GeSe(4). Upon substitution of Zn with the isoelectronic Fe, no charge carriers are introduced in these intrinsic semiconductors. However, a change in lattice parameters, expressed in an elongation of the c/a lattice parameter ratio with minimal change in unit cell volume, reveals the existence of a three-stage cation restructuring process of Cu, Zn, and Fe. The resulting local anisotropic structural disorder leads to phonon scattering not normally observed, resulting in an effective approach to reduce the lattice thermal conductivity in this class of materials.

4.
JBJS Rev ; 11(4)2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-37014938

RESUMO

¼: There is a spectrum of midtarsal injuries, ranging from mild midfoot sprains to complex Lisfranc fracture-dislocations. ¼: Use of appropriate imaging can reduce patient morbidity, by reducing the number of missed diagnoses and, conversely, avoiding overtreatment. Weight-bearing radiographs are of great value when investigating the so-called subtle Lisfranc injury. ¼: Regardless of the operative strategy, anatomical reduction and stable fixation is a prerequisite for a satisfactory outcome in the management of displaced injuries. ¼: Fixation device removal is less frequently reported after primary arthrodesis compared with open reduction and internal fixation based on 6 published meta-analyses. However, the indications for further surgery are often unclear, and the evidence of the included studies is of typically low quality. Further high-quality prospective randomized trials with robust cost-effectiveness analyses are required in this area. ¼: We have proposed an investigation and treatment algorithm based on the current literature and clinical experience of our trauma center.


Assuntos
Fraturas Ósseas , Humanos , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/diagnóstico por imagem , Fraturas Ósseas/cirurgia , Redução Aberta/métodos , Estudos Prospectivos , Radiografia
5.
Astrobiology ; 23(8): 846-861, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37192487

RESUMO

The Sample Tubes on the Mars 2020 Perseverance rover were required to meet strict cleanliness standards for possible organic and inorganic contamination introduction to collected samples. There were also strict planetary protection cleanliness standards required to limit possible biological contamination. Together, these sets of standards also applied to associated hardware, like the Sample Tube hermetic seals. This created unique challenges to manufacturing, cleaning, and verifying the final cleanliness state of the Sample Tubes, which are the main focus of this publication. Documenting the final cleanliness state of the Sample Tubes is critical for future analysis of collected martian samples, of significant interest to the scientific community, and will have implications for possible future missions like Mars Sample Return. An accounting of events that led to the final delivered state of the Sample Tubes on Earth with regard to contamination control cleanliness requirements, precision cleaning, processing, and verification are provided.


Assuntos
Marte , Voo Espacial , Meio Ambiente Extraterreno , Astronave , Exobiologia , Contenção de Riscos Biológicos
6.
Bone Joint J ; 104-B(11): 1215-1224, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36317352

RESUMO

AIMS: The primary aim of this study was to assess whether patients waiting six months or more for a total hip (THA) or knee (KA) arthroplasty had a deterioration in their health-related quality of life (HRQoL). Secondary aims were to assess changes in frailty and the number of patients living in a state considered to be worse than death (WTD), and factors associated with changes in HRQoL and frailty. METHODS: This cross-sectional study included 326 patients, 150 males (46.0%) and 176 females (54.0%), with a mean age of 68.6 years (SD 9.8) who were randomly selected from waiting lists at four centres and had been waiting for six months or more (median 13 months, interquartile range 10 to 21) for a primary THA (n = 161) or KA (n = 165). The EuroQol five-dimension questionnaire (EQ-5D) and visual analogue scores (EQ-VAS), Rockwood Clinical Frailty Scale (CFS), and 36-Item Short Form Survey subjective change in HRQoL were assessed at the time and recalled for six months earlier. A state that was WTD was defined as an EQ-5D of less than zero. RESULTS: There were significant deteriorations in the EQ-5D (mean 0.175, 95% confidence interval (CI) 0.145 to 0.204; p < 0.001), EQ-VAS (mean 8.6, 95% CI 7.0 to 10.4; < 0.001), and CFS (from 3 "managing well" to 4 "vulnerable"; p < 0.001), and a significant increase in the number of those in a state that was WTD (n = 48; p < 0.001) during the previous six months for the whole cohort. A total of 110 patients (33.7%) stated that their health was much worse and 107 (32.8%) felt it was somewhat worse compared with six months previously. A significantly greater EQ-5D (-0.14, 95% CI 0.08 to 0.28; p = 0.038) and a state that was not WTD (-0.14, 95% CI 0.01 to 0.26; p = 0.031) were associated with a deterioration in the EQ-5D. THA (0.21, 95% CI 0.07 to 0.34; p = 0.002) or a lower (better) CFS (0.14, 95% CI 0.07 to 0.20; p < 0.001) were independently significantly associated with a deterioration in the CFS. CONCLUSION: Patients waiting more than six months for THA or KA had a significant deterioration in their HRQoL and increased frailty, with two-thirds of patients feeling that their health had worsened.Cite this article: Bone Joint J 2022;104-B(11):1215-1224.


Assuntos
Artroplastia de Quadril , Artroplastia do Joelho , Fragilidade , Masculino , Feminino , Humanos , Idoso , Qualidade de Vida , Estudos Transversais
7.
J Hand Microsurg ; 8(1): 49-51, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27616828

RESUMO

Anomalous flexor digitorum superficialis muscles in the hand are an uncommon phenomenon, and therefore present challenges in diagnosis and management. We report a case of a 16-year-old girl presenting with a painful, slowly enlarging palmar swelling. The swelling was investigated with ultrasound and magnetic resonance imaging, and was found to be an anomalous muscle belly of the flexor digitorum superficialis muscle. After careful consideration, multidisciplinary discussion, and thorough imaging, the patient was treated successfully without surgical exploration or excision, in comparison to previously reported cases. The patient was pain free and had no concerns at 8-month follow-up, demonstrating the value of conservative management in these cases.

8.
Adv Mater ; 23(47): 5674-8, 2011 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-22052689

RESUMO

The band structure of PbTe can be manipulated by alloying with MgTe to control the band degeneracy. This is used to stabilize the optimal carrier concentration, making it less temperature dependent, demonstrating a new strategy to improve overall thermoelectric efficiency over a broad temperature range.


Assuntos
Ligas/química , Conservação dos Recursos Naturais/métodos , Chumbo/química , Telúrio/química , Condutividade Elétrica , Magnésio/química , Microscopia Eletrônica de Varredura , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Propriedades de Superfície , Temperatura , Condutividade Térmica , Difração de Raios X
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