The onset of tapering in the early stage of growth of a nanowire.

The early stage of growth of semiconductor nanowires is studied in the case where the sidewall adatoms have a short diffusion length due to a strong desorption. Experimental results are described for the growth of ZnSe nanowires by molecular beam epitaxy. They are discussed and interpreted using the Burton-Cabrera-Frank description of the propagation of steps along the sidewalls, and compared to other II-VI and III-V nanowires. The role of the growth parameters and the resulting shape of the nanowires (cylinder, cone, or both combined) are highlighted.

Restoring the Coherence of Quantum Emitters through Optically Driven Motional Narrowing Forces.

Motional narrowing is a phenomenon by which a quantum state can be entangled with a noisy environment and still retain its intrinsic coherence. Using two optically induced motional forces driving the environmental electrical field amplitude and fluctuations, we present a compelling illustration of the effects of motional narrowing on the energy, line shape, and line width of a single quantum emitter, a Te2 molecule embedded in ZnSe, subject to spectral diffusion. Motional narrowing is achieved in several regimes, irrespectively of the inhomogeneous disorder initially present and the charge reservoir state sourcing the field. The optimal coherence limit set by the radiative rate can be approached by accelerating spectral diffusion into the THz regime. Motional narrowing applies to any quantum systems for which environmental fluctuations can be deliberately accelerated and alleviates the need for perfected materials and devices.

Identifying and mapping the polytypes and orientation relationships in ZnO/CdSe core-shell nanowire arrays.

Identifying and mapping the crystalline phases and orientation relationships on the local scale in core-shell ZnO nanowire heterostructures are of primary importance to improve the interface quality, which governs the performances of the nanoscale devices. However, this represents a major difficulty, especially when the expected polytypes exhibit very similar properties as in the case of CdSe. In the present work, we address that issue in ZnO nanowire heterostructures involving a uniform and highly conformal CdSe shell grown by molecular beam epitaxy. It is shown by x-ray diffraction and Raman spectroscopy through the occurrence of the (101̄0) and (101̄1) diffraction peaks and of the [Formula: see text] mode at 34 cm-1, respectively, that the CdSe shell is mostly crystallized into the wurtzite phase. By using automated crystal phase and orientation mapping with precession (ASTAR) in a transmission electron microscope and thus by benefiting from highly precise electron diffraction patterns, the CdSe shell is found to crystallize also into the minority zinc blende phase. The wurtzite CdSe shell is epitaxially grown on the top of ZnO nanowires, and some specific orientation relationships are mapped and revealed when grown on their vertical sidewalls. Zinc blende CdSe domains are also formed exclusively in the center of wurtzite CdSe grains located on the vertical sidewalls; both wurtzite and zinc blende CdSe crystalline phases have a strong orientation relationship. These findings reveal that ASTAR is a powerful technique to elucidate the structural properties on the local scale and to gain a deeper insight into their crystalline phases and orientation relationships, which is highly promising for many types of semiconducting nanowire heterostructures.

Creatine supplementation and resistance training in vulnerable older women: a randomized double-blind placebo-controlled clinical trial.

This study aimed to examine the efficacy of creatine supplementation, associated or not with resistance training, in vulnerable older women. A 24-week, double-blind, randomized, placebo-controlled trial was performed. Sixty subjects were assigned to compose the following groups: placebo (PL), creatine supplementation (CR), placebo with resistance training (PL+RT), and creatine supplementation with resistance training (CR+RT). The subjects were assessed at baseline and after 24weeks. The primary outcome was muscle strength, as assessed by one-repetition maximum (1-RM) tests. Secondary outcomes included appendicular lean mass, bone mass, biochemical bone markers, and physical function tests. The changes in 1-RM leg press were significantly greater in the CR+RT group (+19.9%) than in the PL (+2.4%) and the CR groups (+3.7%), but not than in the PL+RT group (+15%) (p=0.002, p=0.002, and p=0.357, respectively). The CR+RT group showed superior gains in 1-RM bench press (+10%) when compared with all the other groups (p≤0.05). The CR+RT group (+1.31%) showed greater appendicular lean mass accrual than the PL (-1.2%), the CR (+0.3%), and the PL+RT groups (-0.2%) (p≤0.05). The CR and the PL+RT groups experienced comparable gains in appendicular lean mass (p=0.62), but superior to those seen in the PL group. Changes in fat mass, bone mass and serum bone markers did not significantly differ between the groups (p>0.05). In conclusion, creatine supplementation combined with resistance training improved appendicular lean mass and muscle function, but not bone mass, in older vulnerable women. Clinicaltrials.gov: NCT01472393.

Efeitos da suplementação de creatina combinada ou não ao treinamento físico em mulheres idosas: estudo clínico, randomizado, duplo-cego, controlado por placebo / Effects of creatine supplementation combined or not with exercise training in older women: a clinical, randomized, double-blind, placebo-controlled trial

INTRODUÇÃO: O envelhecimento cada vez maior da população mundial é responsável pelo aumento na prevalência de sarcopenia, osteoporose e incapacidade física em indivíduos idosos mais vulneráveis. OBJETIVOS: Avaliar a eficácia da suplementação de creatina (CR), associada ou não ao treinamento de resistência ou força (RT) em mulheres idosas. MÉTODOS: 60 mulheres voluntárias acima de 60 anos de idade, sedentárias, participaram do estudo clínico randomizado, duplo-cego, controlado por placebo, durante 24 semanas, divididas em quatro grupos : placebo (PL), com suplementação de creatina (CR), placebo com treinamento de resistência (PL + RT) e suplementação de creatina com treinamento de resistência (CR + RT). As voluntárias foram avaliadas antes e depois de 24 semanas de intervenção. A força muscular foi avaliada por testes de uma repetição máxima (1RM). Outras variáveis foram incluídas como massa magra apendicular, massa óssea, marcadores de metabolismo ósseo e testes de capacidade física funcional. RESULTADOS: As alterações no teste de 1RM leg press foram significantemente maiores no grupo CR + RT (+ 19.9%) do que os grupos PL (+ 2.4%) e CR (+ 3.7%), mas não no grupo PL + RT (+ 15%) (p = 0.002, p = 0.002, e p = 0.357, respectivamente). O grupo CR + RT também demonstrou ganhos superiores no teste de 1RM supino (+ 10%) quando comparado com o grupo PL (- 3.1%, p = 0.03). Os grupos PL, CR, e PL + RT tiveram mudanças comparáveis no 1RM supino. O grupo CR + RT (+ 1.31%) apresentou melhora significativa na massa magra apendicular em relação aos grupos PL (- 1.2%), CR (+ 0.3%), e PL + RT (- 0.2%) (p < 0.05). Os grupos CR e PL + RT obtiveram ganhos comparáveis na massa magra apendicular (p = 0.62), porém superiores aos observados no grupo PL. Massa gorda, massa óssea e marcadores séricos de metabolismo ósseo não obtiveram diferenças significativas entre os grupos (p > 0.05). CONCLUSÕES: Suplementação de creatina a longo prazo combinado com treinamento de resistência pode...

INTRODUCTION: The increasing aging of the world population is responsible for the increase in the prevalence of sarcopenia, osteoporosis and physical disability in vulnerable elderly. OBJECTIVES: The aim of this study was to examine the efficacy of creatine supplementation, associated or not with resistance training, in vulnerable older women. METHODS: Sixty subjects were assigned to compose a 24-week, double-blind, randomized, placebo controlled trial, and were divided into 4 groups : placebo (PL), creatine supplementation (CR), placebo with resistance training (PL + RT), and creatine supplementation with resistance training (CR + RT). The subjects were assessed at baseline (Pre) and after 24 weeks (Post). The primary outcome was muscle strength, as assessed by one-maximum (1-RM) tests. Secondary outcomes included appendicular lean mass, bone mass, biochemical bone markers, and physical function tests. RESULTS: The changes in 1-RM leg press were significantly greater in the CR + RT group (+ 19.9%) than in PL (+ 2.4%) and the CR groups (+ 3.7%), but not than in the PL + RT group (+ 15%) (p = 0.002, p = 0.002, and p = 0.357, respectively). The CR + RT group also showed superior gains in 1-RM bench press (+ 10%) when compared with the PL group (- 3.1%, p = 0.03). The PL, CR and PL + RT had comparable changes in 1-RM bench press. The CR + RT group (+ 1,31%) showed greater appendicular lean mass accrual than the PL (- 1,2%), the CR (+ 0.3%), and the PL + RT groups (- 0.2%) (p <0.05). The CR and the PL + RT groups experienced comparable gains in appendicular lean mass (p = 0.62), but superior to those seen in the PL group. Fat mass, bone mass and serum bone markers did not significantly differ between the groups (p > 0.05). CONCLUSIONS: Long-term creatine supplementation combined with resistance training can improve appendicular lean mass and muscle function, but not bone mass, in older vulnerable women...

Atomistic simulations of the optical absorption of type-II CdSe/ZnTe superlattices.

We perform accurate tight binding simulations to design type-II short-period CdSe/ZnTe superlattices suited for photovoltaic applications. Absorption calculations demonstrate a very good agreement with optical results with threshold strongly depending on the chemical species near interfaces.

Central diabetes insipidus induced by tuberculosis in a rheumatoid arthritis patient.

Tuberculosis, a polymorphic disease, is a diagnostic challenge, particularly when arises concomitantly to an autoimmune disease such as rheumatoid arthritis (RA). Herein, the authors describe a 33-year-old woman with nodular RA who was being treated with methotrexate, sulfasalazine and corticosteroids and presented with subcutaneous nodules simultaneously with aseptic meningitis. Mycobacterium tuberculosis was identified in cultures from a biopsy of an axillary nodule. The patient also developed polyuria and polydipsia with normal glycemia; antidiuretic hormone (ADH) treatment before and after a 3% saline infusion test was performed and diabetes insipidus was diagnosed. An encephalic MRI showed sellar and suprasellar masses, suggesting central diabetes insipidus (CDI). The patient received standard tuberculosis (TB) treatment for 6 months and also DDAVP (desmopressin acetate) during this period. Control of CDI was observed. A pre-surgical magnetic resonance imaging (MRI) showed no pituitary mass. It is known that intrasellar tuberculoma occurs in only 1% of TB patients. TB should be considered in the differential diagnosis of CDI, especially in immunosupressed patients and in countries where this infection is a serious public health problem.

Pentoxyphylline in association with vitamin E reduces cutaneous fibrosis in systemic sclerosis.

Systemic sclerosis (SSc) is a disorder characterized by skin thickness and vasculopathy. The objective of the study was to evaluate the therapeutic effect and safety of the association of pentoxyphylline and vitamin E in SSc patients. Twelve SSc patients (American College of Rheumatology criteria) enrolled this 24-week open-label study. Patients received daily 800 mg of pentoxyphylline and 800 UI of vitamin E and were evaluated at 4-week interval. The primary efficacy endpoint was the change in Modified Rodnan Skin Score (MRSS) at week 24. Nine diffuse SSc patients treated 6 months with cyclophosphamide were used as a historical control group. The mean age of the treated group was 43.6 years, and ten of 12 (84%) patients were women. Their mean MRSS reduced from 25.7 to 18.7 (p = 0.03) at 16th week and remained significantly reduced throughout the study. In contrast, only a trend of MRSS reduction was observed in the historical control group (p = 0.06). Two patients started the study with active ischemic ulcers and ended with a complete healing of them. No serious side effects were reported. Pentoxyphylline and vitamin E might be an alternative therapeutic approach in SSc patients.

A high-temperature single-photon source from nanowire quantum dots.

We present a high-temperature single-photon source based on a quantum dot inside a nanowire. The nanowires were grown by molecular beam epitaxy in the vapor-liquid-solid growth mode. We utilize a two-step process that allows a thin, defect-free ZnSe nanowire to grow on top of a broader, cone-shaped nanowire. Quantum dots are formed by incorporating a narrow zone of CdSe into the nanowire. We observe intense and highly polarized photoluminescence even from a single emitter. Efficient photon antibunching is observed up to 220 K, while conserving a normalized antibunching dip of at most 36%. This is the highest reported temperature for single-photon emission from a nonblinking quantum-dot source and principally allows compact and cheap operation by using Peltier cooling.

Anti-endothelial cell antibodies and central nervous system involvement in Behçet's disease.

INTRODUCTION: Previous studies have detected the presence of anti-endothelial cell antibodies (AECA) in patients with Behçet's disease (BD). However, no real evidence exists whether these antibodies exert any influence on clinical presentation and/or activity of this disease. OBJECTIVES: To determine the frequency of AECA in patients with BD and analyze possible clinical associations. METHODS: 50 patients with BD who fulfilled diagnostic criteria were selected. Thirty-seven patients were females, and 13 were males; the mean age was 44 +/- 9 years with a mean follow-up time of 10 +/- 7.5 years. AECA were assayed by ELISA using ECV-304 cells as the antigenic substrate. The prevalence of AECA was determined, and their possible relationships with present and past clinical features were investigated. RESULTS: AECA were detected in the sera of 38% of the patients (IgG in 13, IgM in four, and IgG plus IgM in two). An association was observed between AECA and a previous history of central nervous system involvement (OR= 5.4, p= 0.03). This association was more evident for IgG-AECA (OR= 6.0, p= 0.02). A trend of an increased risk of aneurysms was also observed in patients with IgG-AECA (OR= 2.58, p= 0.77). None of the other clinical characteristics showed a relevant association with these antibodies. CONCLUSION: Our data suggest that IgG-AECA may be a marker of more severe lesions in patients with BD based on the higher frequency of previous central nervous system manifestations in patients who presently display circulating AECA.

Anti-endothelial cell antibodies and central nervous system involvement in Behçet's disease

INTRODUCTION: Previous studies have detected the presence of anti-endothelial cell antibodies (AECA) in patients with Behçet's disease (BD). However, no real evidence exists whether these antibodies exert any influence on clinical presentation and/or activity of this disease. OBJECTIVES: To determine the frequency of AECA in patients with BD and analyze possible clinical associations. METHODS: 50 patients with BD who fulfilled diagnostic criteria were selected. Thirty-seven patients were females, and 13 were males; the mean age was 44 ± 9 years with a mean follow-up time of 10 ± 7.5 years. AECA were assayed by ELISA using ECV-304 cells as the antigenic substrate. The prevalence of AECA was determined, and their possible relationships with present and past clinical features were investigated. RESULTS: AECA were detected in the sera of 38 percent of the patients (IgG in 13, IgM in four, and IgG plus IgM in two). An association was observed between AECA and a previous history of central nervous system involvement (OR= 5.4, p= 0.03). This association was more evident for IgG-AECA (OR= 6.0, p= 0.02). A trend of an increased risk of aneurysms was also observed in patients with IgG-AECA (OR= 2.58, p= 0.77). None of the other clinical characteristics showed a relevant association with these antibodies. CONCLUSION: Our data suggest that IgG-AECA may be a marker of more severe lesions in patients with BD based on the higher frequency of previous central nervous system manifestations in patients who presently display circulating AECA.

INTRODUÇÃO: Estudos anteriores detectaram a presence de anticorpos anti-célula endotelial (AACE) em pacientes com doença de Behçet, porém não há nenhuma evidência se a presença destes anticorpos exerce alguma influência na apresentação clínica ou atividade da doença. OBJETIVOS: Determinar a freqüência de AACE em pacientes com doença de Behçet e analisar possíveis associações clínicas. MÉTODOS: Foram selecionados 50 pacientes que preencheram corretamente os critérios diagnósticos para a doença de Behçet. Trinta e sete pacientes eram do sexo feminino e 13 do sexo masculino, média de idade de 44 ± 9 anos e tempo médio de seguimento de 10 ± 7,5 anos. O AACE foram analisados por ELISA utilizando células ECV-304 como substrato antigênico. A prevalência de AACE foi determinada e foram investigadas possíveis relações com características clínicas atuais e pregressas. RESULTADOS: Os AACE foram detectados no soro de 38 por cento dos pacientes (13 na forma IgG, 4 IgM e 2 nas formas IgG e IgM). Observamos uma associação entre o AACE e história pregressa de envolvimento de sistema nervoso central (OR=5,4; p=0,03). Esta associação era mais evidente para o AACE na forma IgG (OR=6,0; p=0,02). Observamos também uma tendência de risco aumentado de aneurismas em pacientes com AACE na forma IgG (OR=2,58; p=0,77). Nenhuma outra característica clínica mostrou-se relevante com o anticorpo estudado. CONCLUSÃO: Nossos dados sugerem que o AACE na forma IgG pode ser uma marcador de lesão mais grave em pacientes com doença de Behçet baseado no fato de encontrarmos uma maior freqüência de história pregressa de manifestação de sistema nervoso central em pacientes com AACE circulante.

Spontaneous coherent phase transition of polaritons in CdTe microcavities.

We report on evidence for polariton condensation out of a reservoir of incoherent polaritons. Polariton population and first-order coherence are investigated by spectroscopic imaging of the far-field emission of a CdTe-based microcavity under nonresonant pumping. With increasing pumping power, stimulated emission with thresholdlike behavior and spectral narrowing is observed in the strong exciton-photon coupling regime. We show that it comes from a narrow ring in k space, exhibiting enhanced spatial and angular coherence at the stimulation onset.