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The applications of lanthanide-doped upconversion nanocrystals in biological imaging, photonics, photovoltaics and therapeutics have fuelled a growing demand for rational control over the emission profiles of the nanocrystals. A common strategy for tuning upconversion luminescence is to control the doping concentration of lanthanide ions. However, the phenomenon of concentration quenching of the excited state at high doping levels poses a significant constraint. Thus, the lanthanide ions have to be stringently kept at relatively low concentrations to minimize luminescence quenching. Here we describe a new class of upconversion nanocrystals adopting an orthorhombic crystallographic structure in which the lanthanide ions are distributed in arrays of tetrad clusters. Importantly, this unique arrangement enables the preservation of excitation energy within the sublattice domain and effectively minimizes the migration of excitation energy to defects, even in stoichiometric compounds with a high Yb(3+) content (calculated as 98 mol%). This allows us to generate an unusual four-photon-promoted violet upconversion emission from Er(3+) with an intensity that is more than eight times higher than previously reported. Our results highlight that the approach to enhancing upconversion through energy clustering at the sublattice level may provide new opportunities for light-triggered biological reactions and photodynamic therapy.
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BACKGROUND: The aim was to predict survival of glioblastoma at 8 months after radiotherapy (a period allowing for completing a typical course of adjuvant temozolomide), by applying deep learning to the first brain MRI after radiotherapy completion. METHODS: Retrospective and prospective data were collected from 206 consecutive glioblastoma, isocitrate dehydrogenase -wildtype patients diagnosed between March 2014 and February 2022 across 11 UK centers. Models were trained on 158 retrospective patients from 3 centers. Holdout test sets were retrospective (nâ =â 19; internal validation), and prospective (nâ =â 29; external validation from 8 distinct centers). Neural network branches for T2-weighted and contrast-enhanced T1-weighted inputs were concatenated to predict survival. A nonimaging branch (demographics/MGMT/treatment data) was also combined with the imaging model. We investigated the influence of individual MR sequences; nonimaging features; and weighted dense blocks pretrained for abnormality detection. RESULTS: The imaging model outperformed the nonimaging model in all test sets (area under the receiver-operating characteristic curve, AUC Pâ =â .038) and performed similarly to a combined imaging/nonimaging model (Pâ >â .05). Imaging, nonimaging, and combined models applied to amalgamated test sets gave AUCs of 0.93, 0.79, and 0.91. Initializing the imaging model with pretrained weights from 10 000s of brain MRIs improved performance considerably (amalgamated test sets without pretraining 0.64; Pâ =â .003). CONCLUSIONS: A deep learning model using MRI images after radiotherapy reliably and accurately determined survival of glioblastoma. The model serves as a prognostic biomarker identifying patients who will not survive beyond a typical course of adjuvant temozolomide, thereby stratifying patients into those who might require early second-line or clinical trial treatment.
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Neoplasias Encefálicas , Glioblastoma , Imageamento por Ressonância Magnética , Humanos , Glioblastoma/diagnóstico por imagem , Glioblastoma/radioterapia , Glioblastoma/mortalidade , Glioblastoma/patologia , Imageamento por Ressonância Magnética/métodos , Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Feminino , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Estudos Prospectivos , Idoso , Prognóstico , Aprendizado Profundo , Adulto , Taxa de Sobrevida , Seguimentos , Temozolomida/uso terapêuticoRESUMO
This work presents a combined approach of kinetic control and thermodynamic selection for the synthesis of monodisperse 19 gold atom nanoclusters protected by thiolate groups. The step of kinetic control allows the formation of a proper size distribution of initial size-mixed Au(n)(SR)(m) nanoclusters following the reduction of a gold precursor. Unlike the synthesis of Au(25)(SR)(18) nanoclusters, which involves rapid reduction of the gold precursor by NaBH(4) followed by size focusing, the synthesis of 19-atom nanoclusters requires slow reduction effected by a weaker reducing agent, borane-tert-butylamine complex. The initially formed mixture of nanoclusters then undergoes size convergence into a monodisperse product by means of a prolonged aging process. The nanocluster formula was determined to be Au(19)(SC(2)H(4)Ph)(13). This work demonstrates the importance of both kinetic control of the initial size distribution of nanoclusters prior to size focusing and subsequent thermodynamic selection of stable nanoclusters as the final product.
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Termodinâmica , Ouro , Cinética , Nanopartículas Metálicas , Nanoestruturas , Tamanho da Partícula , Substâncias Redutoras , Compostos de SulfidrilaRESUMO
Herein, we present the structural characterization of the core and surface of colloidally stable ultrathin bismuth sulfide (Bi(2)S(3)) nanowires using X-ray Absorption Spectroscopy (EXAFS and XANES), X-ray Photoelectron Spectroscopy (XPS), and Nuclear Magnetic Resonance (NMR). These three techniques allowed the conclusive structural characterization of the inorganic core as well as the coordination chemistry of the surface ligands of these structures, despite the absence of significant translational periodicity dictated by their ultrathin diameter (1.6 nm) and their polycrystallinity. The atomic structure of the inorganic core is analogous to bulk bismuthinite, but Bi atoms display a remarkably higher coordination number than in the bulk. This can be only explained by a model in which each bismuth atom at the surface (or in close proximity to it) is bound to at least one ligand at any time.
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Bismuto/química , Nanopartículas/química , Nanofios/química , Sulfetos/química , Análise Espectral , Propriedades de SuperfícieRESUMO
PURPOSE: The purpose of this study was to determine whether ankle brace use in university-level varsity volleyball athletes affected their 3-step spike jump height and whether certain types of ankle braces have a greater effect on jump height. METHODS: Nine male university-level varsity volleyball athletes participated in a repeated-measures design study in which each athlete performed three 3-step volleyball spike jumps in 3 ankle brace conditions (soft, rigid, and no brace). Vertical jump height was measured by the Vertec device and video motion analysis at a university biomechanics research laboratory. RESULTS: Vertical jump heights were significantly lower in both brace conditions (soft, 2.3 cm, standard deviation [SD] 1.2 cm, P < .001; rigid, 1.7 cm, SD 0.9 cm, P < .003) compared with the no-brace condition, and no differences in vertical jump height were observed between the brace conditions (0.6 cm, SD 0.3, P = .3). There was a negative correlation between body fat percentage and vertical jump height (r = -0.075, P = .02). The Vertec device reliably measured vertical jump in all 3 conditions. The no-brace vertical ground reaction forces during the loading phase were significantly greater than brace conditions. Ankle range of motion was greatest in the no-brace condition. CONCLUSIONS: Results from this study suggests that high-performance athletes wearing ankle braces experience a significant decrease in vertical jump height independent of the type of ankle brace worn. CLINICAL RELEVANCE: Sports physicians and health care providers caring for high-level athletes should counsel athletes on the trade-offs of wearing protective equipment in sport, as potential decreases in sports performance can lead to increased injury prevention. LEVEL OF EVIDENCE: III.
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Destruction of the nasal septum and nasal bones by Mycobacterium leprae and subsequent infection is still seen regularly in leprosy endemic areas. The social stigma associated with this deformity is significant. Many different procedures have been developed to reconstruct the nose. Patients operated on at Anandaban Hospital and the Green Pastures Hospital and Rehabilitation Center between 1986 and 2001 were reviewed. There were 48 patients with an average age of 47 years. Five deformities were mild, 22 were moderate, 13 were severe, and eight were not graded. Bone grafting with nasolabial skin flaps was performed in 14 cases, bone grafting alone was performed in 10 cases, flaps alone were performed in seven cases, and cartilage grafting was performed in 10 cases. In three patients, a prosthesis was inserted, and in three patients a gull-wing forehead flap was performed. Overall, excellent or good cosmetic results were obtained in 83 percent of cases. Grafting with conchal cartilage was associated with the best cosmetic results and had minimal complications. Bone grafting with or without nasolabial flaps was associated with a 50 percent complication rate of infection or graft resorption. In mild to moderate deformities, cartilage grafting is recommended; for more severe deformities, bone grafting with bony fixation and skin flaps is recommended. Perioperative antibiotics must be used, and these procedures should be performed by an experienced surgeon. In very severe cases with skin deficiency, reconstruction with a forehead flap gives good results.
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Hanseníase/cirurgia , Deformidades Adquiridas Nasais/cirurgia , Rinoplastia/métodos , Adulto , Transplante Ósseo/métodos , Cartilagem/transplante , Estética , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Nepal , Complicações Pós-Operatórias/etiologia , Estudos Retrospectivos , Retalhos CirúrgicosRESUMO
One hundred and fifty-six opponensplasties carried out on 115 patients at Anandaban Hospital between 1987 and 1997 were reviewed. In most cases a flexor digitalis superficialis opponensplasty was performed. The outcome was assessed by measuring the finger to which the thumb could obtain a pinch grip, the gap between the thumb and little metacarpophalangeal joints, and the satisfaction of the patient. The objective assessments demonstrated excellent or good results in 89%. Good or fair patient satisfaction was obtained in 93%. Early complications were seen in seven cases (4%). Objective measurements of outcome and patient satisfaction were not always in agreement, indicating that objective measures do not adequately assess the success of surgery from the patient's perspective. We thus conclude that subjective measurements of results are an important measure of success and should be included in the evaluation of surgical results.
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Contratura/cirurgia , Dedos/cirurgia , Deformidades Adquiridas da Mão/cirurgia , Força da Mão/fisiologia , Hanseníase Tuberculoide/cirurgia , Transferência Tendinosa/métodos , Tendões/cirurgia , Polegar/cirurgia , Neuropatias Ulnares/cirurgia , Adulto , Feminino , Dedos/inervação , Seguimentos , Humanos , Masculino , Articulação Metacarpofalângica/cirurgia , Pessoa de Meia-Idade , Nepal , Amplitude de Movimento Articular/fisiologia , Estudos Retrospectivos , Polegar/inervaçãoRESUMO
OBJECTIVES: To investigate the impact of depression and its treatment on health-related quality of life (HRQoL) in a naturalistic, primary care setting in the UK. METHODS: The Factors Influencing Depression Endpoints Research (FINDER) study was a European, 6-month, prospective, observational study designed to estimate HRQoL in patients with a clinical diagnosis of depression. This paper examines primary care patients recruited in the UK. HRQoL was measured at baseline and at 3 and 6 months after starting antidepressant therapy using the Short Form 36 Health Status Survey and the European Quality of Life-5 Dimensions (EQ-5D). Regression analysis was used to identify baseline and treatment variables independently and significantly associated with HRQoL. Further analyses included the effect of caseness for depression on HRQoL, the effect of moderate/severe pain at baseline on HRQoL, changes in overall pain, pain interference scores, and the use of different antidepressants by pain cohort. RESULTS: A total of 608 patients was recruited from 58 centres and mean HRQoL was significantly below reported population norms at baseline. Most improvement in HRQoL was seen at 3 months for EQ-5D, with small additional improvement at 6 months. Worse HRQoL outcomes at 6 months were associated with higher somatic symptoms score, duration of depression at baseline, and switching within antidepressant classes. Patients meeting the criteria for caseness for depression, or with significant pain at baseline showed less improvement in HRQoL scores at 6 months. CONCLUSION: Patients presenting with depression in primary care show reduced HRQoL compared to population norms. HRQoL improves during antidepressant treatment particularly within the first 3 months. Nonpainful somatic symptoms, socioeconomic factors, depression variables and switching within antidepressant class predict poor HRQoL outcome. Pain is a common symptom in depressed patients and remains after 6 months' treatment. Pain and somatic symptoms should be assessed in all patients with depression in primary care.
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Two experiments explored the neural mechanisms underlying the learning and consolidation of novel spoken words. In Experiment 1, participants learned two sets of novel words on successive days. A subsequent recognition test revealed high levels of familiarity for both sets. However, a lexical decision task showed that only novel words learned on the previous day engaged in lexical competition with similar-sounding existing words. Additionally, only novel words learned on the previous day exhibited faster repetition latencies relative to unfamiliar controls. This overnight consolidation effect was further examined using fMRI to compare neural responses to existing and novel words learned on different days prior to scanning (Experiment 2). This revealed an elevated response for novel compared with existing words in left superior temporal gyrus (STG), inferior frontal and premotor regions, and right cerebellum. Cortical activation was of equivalent magnitude for unfamiliar novel words and items learned on the day of scanning but significantly reduced for novel words learned on the previous day. In contrast, hippocampal responses were elevated for novel words that were entirely unfamiliar, and this elevated response correlated with postscanning behavioral measures of word learning. These findings are consistent with a dual-learning system account in which there is a division of labor between medial-temporal systems that are involved in initial acquisition and neocortical systems in which representations of novel spoken words are subject to overnight consolidation.
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Linguística , Memória/fisiologia , Neocórtex/fisiologia , Aprendizagem Verbal/fisiologia , Estimulação Acústica , Adolescente , Adulto , Análise de Variância , Mapeamento Encefálico , Tomada de Decisões/fisiologia , Feminino , Lateralidade Funcional , Humanos , Processamento de Imagem Assistida por Computador/métodos , Masculino , Neocórtex/irrigação sanguínea , Testes Neuropsicológicos , Oxigênio/sangue , Tempo de Reação/fisiologia , Fatores de Tempo , Adulto JovemRESUMO
Impaired manual functioning often occurs when the hands are exposed to cold temperatures, but the underlying mechanism is not clearly understood. Tactile feedback is thought to provide important information during object manipulations in order to scale and regulate grip forces; however, topical anaesthetic-induced tactile sensation impairments may not realistically simulate the systemic neuromuscular impairment of the whole hand that could occur during cold temperature exposure. In two experiments, we studied the impact of (1) local hand cooling [thermoneutral finger skin temperature, cold (<8 degrees C)] and (2) core body temperature (thermoneutral core body temperature, pre-heated by 0.5 degrees C, pre-cooled by 0.5 degrees C) with cold hands on manual dexterity and the ability to control and co-ordinate grip forces during a cyclical load-lifting task. In Experiment 1 (n = 10), hand cooling significantly decreased Purdue Pegboard performance (P = 0.002), while increasing grip force by approximately 5 N during the cyclical load-lifting task compared to thermoneutral (P = 0.037). The temporal co-ordination of grip and load forces was unaffected by hand cooling. In Experiment 2 (n = 11), pegboard performance was impaired following hand cooling (P < 0.001), and to a greater extent when the body was pre-cooled (p < 0.001). However, neither grip force (P = 0.99) nor the temporal co-ordination of grasping and lifting forces (P = 0.85) were affected by core body temperature. These data support the existence of a robust centrally controlled feedforward system able to anticipate the dynamics of manual manipulations and accordingly regulate the temporal co-ordination of fingertip forces during object manipulation. This centrally controlled mechanism appears to differ from the mechanisms governing other aspects of manual dexterity.