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1.
Opt Express ; 27(11): 15638-15648, 2019 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-31163758

RESUMEN

Generation of octave-spanning spectrum that spans from 570 nm to 1300 nm utilizing 1030 nm 170 fs pulses from a Yb:KGW laser and a two-stage multiple-plate arrangement is demonstrated. 3.21 fs sub-single-cycle pulses are obtained after dispersion compensation. The high compression ratio of more than 50 times is achieved for two scenarios with widely different parameters including high input peak power at 1 kHz repetition rate and modest peak power at a high repetition rate of 100 kHz. The output pulses have good spatial mode quality and exhibit long-term stability. The achieved compression ratio and flexibility are unprecedented in ultrafast pulse compression to single-cycle regime. The experiments demonstrate that the technique of multiple-plate pulse compression is versatile and applicable for a wide range of laser pulse parameters.

2.
Opt Express ; 26(7): 8941-8956, 2018 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-29715854

RESUMEN

The generation of high average power, carrier-envelope phase (CEP) stable, near-single-cycle pulses at a repetition rate of 100 kHz is demonstrated using an all solid-state setup. By exploiting self-phase modulation in thin quartz plates and air, the spectrum of intense pulses from a high-power, high repetition rate non-collinear optical parametric chirped pulse amplifier (NOPCPA) is extended to beyond one octave, and pulse compression down to 3.7 fs is achieved. The octave-spanning spectrum furthermore allows performing straightforward f-to-2f interferometry by frequency-doubling the long-wavelength part of the spectrum. Excellent CEP-stability is demonstrated for extended periods of time. A full spatio-spectral characterization of the compressed pulses shows only minor asymmetries between the two perpendicular beam axes. We believe that the completed system represents the first laser system satisfying all requirements for performing high repetition rate attosecond pump-probe experiments with fully correlated detection of all ions and electrons produced in the experiment.

3.
Osteoporos Int ; 28(1): 1-19, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-27613721

RESUMEN

The purpose of this review is to assess the most recent evidence in the management of primary hyperparathyroidism (PHPT) and provide updated recommendations for its evaluation, diagnosis and treatment. A Medline search of "Hyperparathyroidism. Primary" was conducted and the literature with the highest levels of evidence were reviewed and used to formulate recommendations. PHPT is a common endocrine disorder usually discovered by routine biochemical screening. PHPT is defined as hypercalcemia with increased or inappropriately normal plasma parathyroid hormone (PTH). It is most commonly seen after the age of 50 years, with women predominating by three to fourfold. In countries with routine multichannel screening, PHPT is identified earlier and may be asymptomatic. Where biochemical testing is not routine, PHPT is more likely to present with skeletal complications, or nephrolithiasis. Parathyroidectomy (PTx) is indicated for those with symptomatic disease. For asymptomatic patients, recent guidelines have recommended criteria for surgery, however PTx can also be considered in those who do not meet criteria, and prefer surgery. Non-surgical therapies are available when surgery is not appropriate. This review presents the current state of the art in the diagnosis and management of PHPT and updates the Canadian Position paper on PHPT. An overview of the impact of PHPT on the skeleton and other target organs is presented with international consensus. Differences in the international presentation of this condition are also summarized.


Asunto(s)
Hiperparatiroidismo Primario/diagnóstico por imagen , Humanos , Hipercalcemia/etiología , Hiperparatiroidismo Primario/complicaciones , Hiperparatiroidismo Primario/epidemiología , Hiperparatiroidismo Primario/terapia , Incidencia , Imagen por Resonancia Magnética/métodos , Nefrolitiasis/etiología , Paratiroidectomía , Prevalencia , Cintigrafía/métodos , Tomografía Computarizada por Rayos X/métodos
4.
Opt Express ; 24(7): 7224-31, 2016 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-27137014

RESUMEN

We analyze femtosecond supercontinuum generation in a distribution of thin solid plates to show that the distributed scheme inhibits processes leading to pulse breakup while allowing spectral expansion to proceed as desired. We introduce basic criteria for setting the plate thickness or initial laser intensity and the location of each plate in the laser beam path and confirm that under these conditions a fully-coherent and intense supercontinuum can be generated for input peak power of as much as two thousand times the critical power for self-focusing of the solid medium.

5.
Osteoporos Int ; 27(5): 1747-54, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26659066

RESUMEN

UNLABELLED: The study aimed to prospectively evaluate if serum calcium is related to diabetes incidence in Hong Kong Chinese. The results showed that serum calcium has a significant association with increased risk of diabetes. The result of meta-analysis reinforced our findings. INTRODUCTION: This study aimed to evaluate the association of serum calcium, including serum total calcium and albumin-corrected calcium, with incident diabetes in Hong Kong Chinese. METHODS: We conducted a retrospective cohort study in 6096 participants aged 20 or above and free of diabetes at baseline. Serum calcium was measured at baseline. Incident diabetes was determined from several electronic databases. We also searched relevant databases for studies on serum calcium and incident diabetes and conducted a meta-analysis using fixed-effect modeling. RESULTS: During 59,130.9 person-years of follow-up, 631 participants developed diabetes. Serum total calcium and albumin-corrected calcium were associated with incident diabetes in the unadjusted model. After adjusting for demographic and clinical variables, the association remained significant only for serum total calcium (hazard ratio (HR), 1.32 (95 % confidence interval (CI), 1.02-1.70), highest vs. lowest quartile). In a meta-analysis of four studies including the current study, both serum total calcium (pooled risk ratio (RR), 1.38 (95 % CI, 1.15-1.65); I (2) = 5 %, comparing extreme quantiles) and albumin-corrected calcium (pooled RR, 1.29 (95 % CI, 1.03-1.61); I (2) = 0 %, comparing extreme quantiles) were associated with incident diabetes. Penalized regression splines showed that the association of incident diabetes with serum total calcium and albumin-correlated calcium was non-linear and linear, respectively. CONCLUSIONS: Elevated serum calcium concentration is associated with incident diabetes. The mechanism underlying this association warrants further investigation.


Asunto(s)
Calcio/sangre , Diabetes Mellitus Tipo 2/sangre , Adulto , Anciano , Anciano de 80 o más Años , Diabetes Mellitus Tipo 2/epidemiología , Hong Kong/epidemiología , Humanos , Incidencia , Persona de Mediana Edad , Estudios Observacionales como Asunto , Estudios Retrospectivos , Factores de Riesgo , Albúmina Sérica/análisis , Adulto Joven
6.
Opt Express ; 22(4): 4075-82, 2014 Feb 24.
Artículo en Inglés | MEDLINE | ID: mdl-24663729

RESUMEN

An octave-spanning coherent supercontinuum is generated by non-collinear Raman-assisted four-wave mixing in single-crystal diamond using 7.7 fs laser pulses that have been chirped to about 420 fs in duration. The use of ultrabroad bandwidth pulses as input results in substantial overlap of the generated spectrum of the anti-Stokes sidebands, creating a phase-locked supercontinuum when all the sidebands are combined to overlap in time and space. The overall bandwidth of the generated supercontinuum is sufficient to support its compression to isolated few-to-single cycle attosecond transients. The significant spectral overlap of adjacent anti-Stokes sidebands allows the utilization of straight-forward spectral interferometry to test the relative phase coherence of the anti-Stokes outputs and is demonstrated here for two adjacent pairs of sidebands. The method can subsequently be employed to set the relative phase of the sidebands for pulse compression and for the synthesis of arbitrary field transients.

7.
Osteoporos Int ; 25(3): 1017-23, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24196720

RESUMEN

SUMMARY: A total of 2,266 postmenopausal Chinese women were followed for 4.5 years to determine the incidence of new fractures. The positive predictive value, negative predictive value, sensitivity and specificity of different treatment strategies were compared. Using a fixed optimal threshold calculated from receiver operating characteristics (ROC) curve had the highest sensitivity but lowest specificity. INTRODUCTION: There is no specific intervention threshold based on FRAX to guide treatment for Asian populations. This prospective study sought to determine the impact of applying different intervention thresholds to a cohort of Chinese postmenopausal women. METHODS: This study was part of the Hong Kong Osteoporosis Study. A total of 2,266 treatment-naïve postmenopausal women underwent clinical risk factor and BMD assessments. The subjects were followed to assess fractures. We calculated the FRAX probability of major osteoporotic fractures corresponding to women with prior fractures but no other clinical risk factors. Different treatment strategies which include treating women with prior fractures, women with age-specific FRAX probability corresponding to those with prior fractures, women with osteoporosis as well as women with FRAX probability above a fixed cut-off based on optimizing sensitivity and specificity on the ROC curve were compared. RESULTS: The mean age at baseline was 62.1 ± 8.5 years, and the mean follow-up time was 4.5 ± 2.8 years. One hundred six new major osteoporotic fractures were reported. An optimal (FRAX, with BMD) cut-off point of 9.95 % was identified. All strategies had negative predictive value of >90 %. Using a fixed cut-off had the highest sensitivity (62.3 %) but lowest specificity (73.5 %) and positive predictive value (10.3 %). Using a fixed cut-off would direct treatment from younger women with lower absolute risk to elderly women with higher absolute risk. CONCLUSION: Targeting only women with prior fractures is unlikely to reduce fracture burden. Other treatment strategies with higher sensitivity need to be considered but they have different shortcomings.


Asunto(s)
Fracturas Osteoporóticas/prevención & control , Absorciometría de Fotón/métodos , Adulto , Anciano , Anciano de 80 o más Años , Densidad Ósea/fisiología , Estudios de Cohortes , Técnicas de Apoyo para la Decisión , Femenino , Hong Kong/epidemiología , Humanos , Persona de Mediana Edad , Osteoporosis Posmenopáusica/diagnóstico , Osteoporosis Posmenopáusica/epidemiología , Osteoporosis Posmenopáusica/fisiopatología , Osteoporosis Posmenopáusica/terapia , Fracturas Osteoporóticas/epidemiología , Fracturas Osteoporóticas/etiología , Fracturas Osteoporóticas/fisiopatología , Valor Predictivo de las Pruebas , Medición de Riesgo/métodos , Factores de Riesgo
8.
Light Sci Appl ; 12(1): 34, 2023 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-36732493

RESUMEN

Ultrashort energetic terahertz (THz) pulses have created an exciting new area of research on light interactions with matter. For material studies in small laboratories, widely tunable femtosecond THz pulses with peak field strength close to MV cm-1 are desired. Currently, they can be largely acquired by optical rectification and difference frequency generation in crystals without inversion symmetry. We describe in this paper a novel scheme of THz pulse generation with no frequency tuning gap based on Raman-resonance-enhanced four-wave mixing in centrosymmetric media, particularly diamond. We show that we could generate highly stable, few-cycle pulses with near-Gaussian spatial and temporal profiles and carrier frequency tunable from 5 to >20 THz. They had a stable and controllable carrier-envelop phase and carried ~15 nJ energy per pulse at 10 THz (with a peak field strength of ~1 MV cm-1 at focus) from a 0.5-mm-thick diamond. The measured THz pulse characteristics agreed well with theoretical predictions. Other merits of the scheme are discussed, including the possibility of improving the THz output energy to a much higher level.

9.
Osteoporos Int ; 23(1): 131-42, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21927923

RESUMEN

UNLABELLED: Gene-based association approach could be regarded as a complementary analysis to the single SNP association analysis. We meta-analyzed the findings from the gene-based association approach using the genome-wide association studies (GWAS) data from Chinese and European subjects, confirmed several well established bone mineral density (BMD) genes, and suggested several novel BMD genes. INTRODUCTION: The introduction of GWAS has greatly increased the number of genes that are known to be associated with common diseases. Nonetheless, such a single SNP GWAS has a lower power to detect genes with multiple causal variants. We aimed to assess the association of each gene with BMD variation at the spine and hip using gene-based GWAS approach. METHODS: We studied 778 Hong Kong Southern Chinese (HKSC) women and 5,858 Northern Europeans (dCG); age, sex, and weight were adjusted in the model. The main outcome measure was BMD at the spine and hip. RESULTS: Nine genes showed suggestive p value in HKSC, while 4 and 17 genes showed significant and suggestive p values respectively in dCG. Meta-analysis using weighted Z-transformed test confirmed several known BMD genes and suggested some novel ones at 1q21.3, 9q22, 9q33.2, 20p13, and 20q12. Top BMD genes were significantly associated with connective tissue, skeletal, and muscular system development and function (p < 0.05). Gene network inference revealed that a large number of these genes were significantly connected with each other to form a functional gene network, and several signaling pathways were strongly connected with these gene networks. CONCLUSION: Our gene-based GWAS confirmed several BMD genes and suggested several novel BMD genes. Genetic contribution to BMD variation may operate through multiple genes identified in this study in functional gene networks. This finding may be useful in identifying and prioritizing candidate genes/loci for further study.


Asunto(s)
Pueblo Asiatico/genética , Densidad Ósea/genética , Estudio de Asociación del Genoma Completo , Osteoporosis/genética , Población Blanca/genética , Adulto , Anciano , Femenino , Cuello Femoral/fisiología , Redes Reguladoras de Genes , Predisposición Genética a la Enfermedad , Genotipo , Hong Kong/epidemiología , Humanos , Islandia/epidemiología , Vértebras Lumbares/fisiología , Persona de Mediana Edad , Osteoporosis/etnología , Osteoporosis/fisiopatología , Polimorfismo de Nucleótido Simple
10.
Osteoporos Int ; 23(3): 871-8, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21562875

RESUMEN

UNLABELLED: We followed 2,266 postmenopausal Chinese women for 4.5 years to determine which model best predicts osteoporotic fracture. A model that contains ethnic-specific risk factors, some of which reflect frailty, performed as well as or better than the well-established FRAX model. INTRODUCTION: Clinical risk assessment, with or without T-score, can predict fractures in Chinese postmenopausal women although it is unknown which combination of clinical risk factors is most effective. This prospective study sought to compare the accuracy for fracture prediction using various models including FRAX, our ethnic-specific clinical risk factors (CRF) and other simple models. METHODS: This study is part of the Hong Kong Osteoporosis Study. A total of 2,266 treatment naïve postmenopausal women underwent clinical risk factor and bone mineral density assessment. Subjects were followed up for outcome of major osteoporotic fracture and receiver operating characteristic (ROC) curves for different models were compared. The percentage of subjects in different quartiles of risk according to various models who actually fractured was also compared. RESULTS: The mean age at baseline was 62.1 ± 8.5 years and mean follow-up time was 4.5 ± 2.8 years. A total of 106 new major osteoporotic fractures were reported, of which 21 were hip fractures. Ethnic-specific CRF with T-score performed better than FRAX with T-score (based on both Chinese normative and National Health and Nutrition Examination Survey (NHANES) databases) in terms of AUC comparison for prediction of major osteoporotic fracture. The two models were similar in hip fracture prediction. The ethnic-specific CRF model had a 10% higher sensitivity than FRAX at a specificity of 0.8 or above. CONCLUSION: CRF related to frailty and differences in lifestyle between populations are likely to be important in fracture prediction. Further work is required to determine which and how CRF can be applied to develop a fracture prediction model in our population.


Asunto(s)
Osteoporosis Posmenopáusica/epidemiología , Fracturas Osteoporóticas/epidemiología , Absorciometría de Fotón/métodos , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Algoritmos , Pueblo Asiatico/psicología , Pueblo Asiatico/estadística & datos numéricos , Densidad Ósea/fisiología , Estudios de Cohortes , Femenino , Cuello Femoral/fisiopatología , Fracturas de Cadera/epidemiología , Fracturas de Cadera/etiología , Fracturas de Cadera/fisiopatología , Hong Kong/epidemiología , Humanos , Estilo de Vida/etnología , Vértebras Lumbares/fisiopatología , Persona de Mediana Edad , Osteoporosis Posmenopáusica/complicaciones , Osteoporosis Posmenopáusica/fisiopatología , Fracturas Osteoporóticas/etiología , Fracturas Osteoporóticas/fisiopatología , Medición de Riesgo/métodos
11.
Osteoporos Int ; 23(7): 1877-87, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-22215184

RESUMEN

SUMMARY: Periostin (POSTN) as a regulator of osteoblast differentiation and bone formation may affect susceptibility to osteoporosis. This study suggests POSTN as a candidate gene for bone mineral density (BMD) variation and vertebral fracture risk, which could better our understanding about the genetic pathogenesis of osteoporosis and will be useful in clinic in the future. INTRODUCTION: The genetic determination of osteoporosis is complex and ill-defined. Periostin (POSTN), an extracellular matrix secreted by osteoblasts and a regulator of osteoblast differentiation and bone formation, may affect susceptibility to osteoporosis. METHODS: We adopted a tag-single nucleotide polymorphism (SNP) based association method followed by imputation-based verification and identification of a causal variant. The association was investigated in 1,572 subjects with extreme-BMD and replicated in an independent population of 2,509 subjects. BMD was measured by dual X-ray absorptiometry. Vertebral fractures were identified by assessing vertebral height from X-rays of the thoracolumbar spine. Association analyses were performed with PLINK toolset and imputation analyses with MACH software. The top imputation finding was subsequently validated by genotyping. Interactions between POSTN and another BMD-related candidate gene sclerostin (SOST) were analyzed using MDR program and validated by logistical regression analyses. The putative transcription factor binding with target sequence was confirmed by electrophoretic mobility shift assay (EMSA). RESULTS: Several SNPs of POSTN were associated with BMD or vertebral fractures. The most significant polymorphism was rs9547970, located at the -2,327 bp upstream (P = 6.8 × 10(-4)) of POSTN. Carriers of the minor allele G per copy of rs9547970 had 1.33 higher risk of vertebral fracture (P = 0.007). An interactive effect between POSTN and SOST upon BMD variation was suggested (P < 0.01). A specific binding of CDX1 to the sequence of POSTN with the major allele A of rs9547970 but not the variant G allele was confirmed by EMSA. CONCLUSIONS: Our results suggest POSTN as a candidate gene for BMD variation and vertebral fracture risk.


Asunto(s)
Densidad Ósea/genética , Moléculas de Adhesión Celular/genética , Proteínas de Homeodominio/metabolismo , Fracturas Osteoporóticas/genética , Fracturas de la Columna Vertebral/genética , Adulto , Anciano , Sitios de Unión/genética , Moléculas de Adhesión Celular/metabolismo , Femenino , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Fracturas Osteoporóticas/fisiopatología , Polimorfismo de Nucleótido Simple , Unión Proteica/genética , Fracturas de la Columna Vertebral/fisiopatología
12.
Osteoporos Int ; 23(3): 879-85, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21461720

RESUMEN

UNLABELLED: Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. This study observed that Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians, but the vertebral fracture rates were higher, resulting in a high vertebral-to-hip fracture ratio. As a result, estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate. INTRODUCTION: Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. The aim of this study was to report the incidence of clinical vertebral fractures among the Chinese and to compare the vertebral-to-hip fracture risk to other ethnic groups. METHODS: Four thousand, three hundred eighty-six community-dwelling Southern Chinese subjects (2,302 women and 1,810 men) aged 50 or above were recruited in the Hong Kong Osteoporosis Study since 1995. Baseline demographic characteristics and medical history were obtained. Subjects were followed annually for fracture outcomes with a structured questionnaire and verified by the computerized patient information system of the Hospital Authority of the Hong Kong Government. Only non-traumatic incident hip fractures and clinical vertebral fractures that received medical attention were included in the analysis. The incidence rates of clinical vertebral fractures and hip fractures were determined and compared to the published data of Swedish Caucasian and Japanese populations. RESULTS: The mean age at baseline was 62 ± 8.2 years for women and 68 ± 10.3 years for men. The average duration of follow-up was 4.0 ± 2.8 (range, 1 to 14) years for a total of 14,733 person-years for the whole cohort. The incidence rate for vertebral fracture was 194/100,000 person-years in men and 508/100,000 person-years in women, respectively. For subjects above the age of 65, the clinical vertebral fracture and hip fracture rates were 299/100,000 and 332/100,000 person-years, respectively, in men, and 594/100,000 and 379/100,000 person-years, respectively, in women. Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians. At the age of 65 or above, the hip fracture rates for Asian (Hong Kong Chinese and Japanese) men and women were less than half of that in Caucasians, but the vertebral fracture rate was higher in Asians, resulting in a high vertebral-to-hip fracture ratio. CONCLUSIONS: The incidences of vertebral and hip fractures, as well as the vertebral-to-hip fracture ratios vary in Asians and Caucasians. Estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate.


Asunto(s)
Fracturas Osteoporóticas/etnología , Fracturas de la Columna Vertebral/etnología , Distribución por Edad , Anciano , Anciano de 80 o más Años , Antropometría/métodos , Pueblo Asiatico/estadística & datos numéricos , Femenino , Fracturas de Cadera/etnología , Hong Kong/epidemiología , Humanos , Incidencia , Japón/epidemiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Distribución por Sexo , Suecia/epidemiología , Población Blanca/estadística & datos numéricos
13.
Osteoporos Int ; 23(1): 351-63, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21779819

RESUMEN

UNLABELLED: In this 2-year extension of a 3-year study, bazedoxifene showed sustained efficacy in preventing new vertebral fractures in postmenopausal women with osteoporosis and in preventing non-vertebral fractures in higher-risk women. Bazedoxifene significantly increased bone mineral density and reduced bone turnover versus placebo and was generally safe and well tolerated. INTRODUCTION: This study evaluated the efficacy and safety of bazedoxifene for the treatment of postmenopausal osteoporosis over 5 years. METHODS: A total of 4,216 postmenopausal women with osteoporosis were enrolled in this 2-year extension of a 3-year, randomized, double-blind, placebo-controlled, phase 3 trial. In the core study (N = 7,492), subjects received bazedoxifene 20 or 40 mg/day, raloxifene 60 mg/day, or placebo. The raloxifene arm was discontinued after 3 years; subjects receiving bazedoxifene 40 mg were transitioned to bazedoxifene 20 mg after 4 years. Five-year findings are reported for bazedoxifene 20 and 40/20 mg and placebo. Endpoints included incidence of new vertebral fractures (primary) and non-vertebral fractures, and changes in bone mineral density (BMD) and bone turnover markers. RESULTS: At 5 years, the incidence of new vertebral fractures in the intent-to-treat population was significantly lower with bazedoxifene 20 mg (4.5%) and 40/20 mg (3.9%) versus placebo (6.8%; P < 0.05), with relative risk reductions of 35% and 40%, respectively. Non-vertebral fracture incidence was similar among groups. In a subgroup of higher-risk women (n = 1,324; femoral neck T-score ≤-3.0 and/or ≥ 1 moderate or severe or ≥ 2 mild vertebral fracture[s]), bazedoxifene 20 mg reduced non-vertebral fracture risk versus placebo (37%; P = 0.06); combined data for bazedoxifene 20 and 40/20 mg reached statistical significance (34% reduction; P < 0.05). Bazedoxifene significantly increased BMD and reduced bone turnover versus placebo (P < 0.05) and was generally safe and well tolerated. CONCLUSIONS: The findings support a sustained anti-fracture effect of bazedoxifene on new vertebral fractures in postmenopausal osteoporotic women and on non-vertebral fractures in the higher-risk subgroup of women.


Asunto(s)
Conservadores de la Densidad Ósea/uso terapéutico , Indoles/uso terapéutico , Osteoporosis Posmenopáusica/tratamiento farmacológico , Fracturas Osteoporóticas/prevención & control , Anciano , Densidad Ósea/efectos de los fármacos , Conservadores de la Densidad Ósea/administración & dosificación , Conservadores de la Densidad Ósea/efectos adversos , Remodelación Ósea/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Estudios de Seguimiento , Humanos , Indoles/administración & dosificación , Indoles/efectos adversos , Persona de Mediana Edad , Osteoporosis Posmenopáusica/complicaciones , Fracturas Osteoporóticas/etiología , Placebos , Moduladores Selectivos de los Receptores de Estrógeno/administración & dosificación , Moduladores Selectivos de los Receptores de Estrógeno/efectos adversos , Moduladores Selectivos de los Receptores de Estrógeno/uso terapéutico , Fracturas de la Columna Vertebral/etiología , Fracturas de la Columna Vertebral/prevención & control , Resultado del Tratamiento
14.
Opt Lett ; 37(14): 2805-7, 2012 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-22825140

RESUMEN

We demonstrate the use of a nonlinear photonic crystal to generate a harmonic comb and an ultrabroad-band acousto-optic modulator for the field amplitudes and phases of the comb to succeed in synthesizing femtosecond and subfemtosecond optical field waveforms. Nonsinusoidal fields of various shapes are synthesized and verified using shaper-assisted linear cross-correlation. The compact all-solid-state system could lead to the realization of a portable arbitrary optical waveform synthesizer that is analogous in many aspects to an RF function generator.

15.
Nat Commun ; 13(1): 2485, 2022 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-35585047

RESUMEN

The utility of cancer whole genome and transcriptome sequencing (cWGTS) in oncology is increasingly recognized. However, implementation of cWGTS is challenged by the need to deliver results within clinically relevant timeframes, concerns about assay sensitivity, reporting and prioritization of findings. In a prospective research study we develop a workflow that reports comprehensive cWGTS results in 9 days. Comparison of cWGTS to diagnostic panel assays demonstrates the potential of cWGTS to capture all clinically reported mutations with comparable sensitivity in a single workflow. Benchmarking identifies a minimum of 80× as optimal depth for clinical WGS sequencing. Integration of germline, somatic DNA and RNA-seq data enable data-driven variant prioritization and reporting, with oncogenic findings reported in 54% more patients than standard of care. These results establish key technical considerations for the implementation of cWGTS as an integrated test in clinical oncology.


Asunto(s)
Perfilación de la Expresión Génica , Neoplasias , Niño , Estudios de Factibilidad , Perfilación de la Expresión Génica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Humanos , Neoplasias/diagnóstico , Neoplasias/genética , Estudios Prospectivos , Transcriptoma/genética , Secuenciación Completa del Genoma/métodos , Adulto Joven
16.
Opt Express ; 19(8): 7153-60, 2011 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-21503029

RESUMEN

Shaping the ferroelectric domains as waveguide, grating, lens, and prism are key to the successful penetration of periodically-poled ferroelectrics on various wavelength conversion applications. The complicated structures are, however, difficult to be fully characterized, especially the unexpected index contrast at the anti-parallel domain boundaries are typical in the order of 10(-4) or less. An ultrahigh resolution optical coherence tomography was employed to fully characterize the domain boundary and structure properties of a periodically-poled lithium niobate (PPLN) waveguide with an axial resolution of 0.68 µm, an transversal resolution of 3.2 µm, and an index contrast sensitivity of 4x10(-7). The anti-parallel domain uniformity can clearly be seen non-invasively. Dispersion of the ferroelectric material was also obtained from 500 to 750 nm.

17.
Osteoporos Int ; 22(2): 667-74, 2011 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-20503038

RESUMEN

UNLABELLED: This study evaluated the characteristics of patients with vertebral fractures and examined the discriminative ability of clinical risk factors. The findings provide further insights into possible development of a simple, cost-effective scheme for fracture risk assessment using clinical risk factors to identify high-risk patients for further evaluation. INTRODUCTION: Vertebral fractures are the most common complication of osteoporosis. The aim of this study was to evaluate the characteristics of patients with vertebral fractures and to determine the discriminative ability of bone mineral density (BMD) and other clinical risk factors. METHODS: Postmenopausal Southern Chinese women (2,178) enrolled in the Hong Kong Osteoporosis Study since 1995 were prospectively followed up for fracture outcome. Subjects (1,372) with lateral spine radiographs were included in this study. Baseline demographic, BMD, and clinical risk factor information were obtained from a structured questionnaire. RESULTS: Subjects (299; 22%) had prevalent vertebral fractures. The prevalence of vertebral fractures increased with increasing age, number of clinical risk factors, and decreasing BMD. The odds of having a prevalent vertebral fracture per SD reduction in BMD after adjustment for age in Hong Kong Southern Chinese postmenopausal women was 1.5 for the lumbar spine and femoral neck. Analysis of the receiver operating characteristic curve revealed that bone mineral apparent density did not enhance fracture risk prediction. Subjects with ≥ 4 clinical risk factors had 2.3-fold higher odds of having a prevalent vertebral fracture while subjects with ≥ 4 clinical risk factors plus a low BMD (i.e., femoral neck T-score < -2.5) had 2.6-fold. Addition of BMD to clinical risk factors did not enhance the discriminative ability to identify subjects with vertebral fracture. CONCLUSIONS: Based on these findings, we recommend that screening efforts should focus on older postmenopausal women with multiple risk factors to identify women who are likely to have a prevalent vertebral fracture.


Asunto(s)
Densidad Ósea/fisiología , Fracturas de la Columna Vertebral/epidemiología , Absorciometría de Fotón , Anciano , Pueblo Asiatico/etnología , Femenino , Cuello Femoral/diagnóstico por imagen , Hong Kong/epidemiología , Humanos , Vértebras Lumbares , Persona de Mediana Edad , Posmenopausia , Prevalencia , Estudios Prospectivos , Factores de Riesgo
18.
Osteoporos Int ; 22(11): 2799-807, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21234548

RESUMEN

UNLABELLED: This prospective study aimed to determine the risk factors and the 10-year probability of osteoporotic fracture in Southern Chinese men. The findings show substantial population differences in fracture incidence and risk prediction compared to the FRAX(TM) model, and the addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men. INTRODUCTION: Clinical risk factors with or without bone mineral density (BMD) measurements are increasingly recognized as reliable predictors of fracture risk. Prospective data on fracture incidence in Asian men remain sparse. This prospective study aimed to determine the risk factors and the 10-year absolute fracture risk in Southern Chinese men. METHODS: This is a part of the Hong Kong Osteoporosis Study. One thousand eight hundred ten (1,810) community-dwelling, treatment-naive men aged 50 years or above were evaluated. Baseline demographic characteristics, clinical risk factors and BMD were recorded. Ten-year risk of osteoporotic fracture was calculated using Cox proportional hazards models. RESULTS: The mean age of subjects was 68.0 ± 10.3 years. After a mean follow-up period of 3.5±2.9 years (range 1 to 14 years), 37 incident low-trauma fractures were recorded. The incidence for all osteoporotic fractures and hip fractures was 635/100,000 and 123/100,000 person-years, respectively. The most significant predictors of osteoporotic fracture were history of fall (RR 14.5), femoral neck BMD T-score < -2.5 (RR 13.8) and history of fracture (RR 4.4). Each SD reduction in BMD was associated with a 1.8 to 2.6-fold increase in fracture risk. Subjects with seven clinical risk factors and BMD T-score of -1 had an absolute 10-year risk of osteoporotic fracture of 8.9%, but this increased to 22.7% if they also had a femoral neck BMD T-score of -2.5. CONCLUSIONS: These findings show substantial population differences in fracture incidence and risk prediction. The addition of BMD information to clinical risk factor assessment improved fracture risk prediction in Chinese men.


Asunto(s)
Fracturas de Cadera/epidemiología , Osteoporosis/epidemiología , Fracturas Osteoporóticas/epidemiología , Absorciometría de Fotón , Anciano , Anciano de 80 o más Años , Algoritmos , Pueblo Asiatico/etnología , Densidad Ósea , Cuello Femoral/diagnóstico por imagen , Estudios de Seguimiento , Cadera/diagnóstico por imagen , Hong Kong/epidemiología , Humanos , Incidencia , Vértebras Lumbares/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Fracturas Osteoporóticas/etnología , Estudios Prospectivos , Factores de Riesgo
19.
Nat Med ; 6(12): 1335-40, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11100117

RESUMEN

Chronic hypoxia, a hallmark of many tumors, is associated with angiogenesis and tumor progression. Strategies to treat tumors have been developed in which tumor cells are targeted with drugs or gene-therapy vectors specifically activated under hypoxic conditions. Here we report a different approach, in which the normal transcriptional response to hypoxia is selectively disrupted. Our data indicate that specific blockade of the interaction of hypoxia-inducible factor with the CH1 domain of its p300 and CREB binding protein transcriptional coactivators leads to attenuation of hypoxia-inducible gene expression and diminution of tumor growth. Thus, disrupting the normal co-activational response to hypoxia may be a new and useful therapeutic strategy.


Asunto(s)
Hipoxia de la Célula/genética , Proteínas de Unión al ADN/metabolismo , Regulación Neoplásica de la Expresión Génica , Neoplasias Experimentales/terapia , Proteínas Nucleares/metabolismo , Transactivadores/metabolismo , Factores de Transcripción , Animales , Sitios de Unión , Proteína de Unión a CREB , Proteína p300 Asociada a E1A , Terapia Genética/métodos , Factor 1 Inducible por Hipoxia , Subunidad alfa del Factor 1 Inducible por Hipoxia , Ratones , Ratones Desnudos , Neovascularización Patológica , Unión Proteica , Transcripción Genética
20.
Osteoporos Int ; 21(Suppl 4): S605-14, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21058000

RESUMEN

Hip fracture is associated with high morbidity, mortality, and economic burden worldwide. It is also a major risk factor for a subsequent fracture. A literature search on the management of osteoporosis in patients with hip fracture was performed on the Medline database. Only one clinical drug trial was conducted in patients with a recent hip fracture. Further studies that specifically address post-fracture management of hip fracture are needed. The efficacy of anti-osteoporosis medication in older individuals and those at high risk of fall is reviewed in this paper. Adequate nutrition is vital for bone health and to prevent falls, especially in malnourished patients. Protein, calcium, and vitamin D supplementation is associated with increased hip BMD and a reduction in falls. Fall prevention, exercise, and balance training incorporated in a comprehensive rehabilitation program are essential to improve functional disability and survival. Exclusion of secondary causes of osteoporosis and treatment of coexistent medical conditions are also vital. Such a multidisciplinary team approach to the management of hip fracture patients is associated with a better clinical outcome. Although hip fracture is the most serious of all fractures, osteoporosis management should be prioritized to prevent deterioration of health and occurrence of further fracture.


Asunto(s)
Fracturas de Cadera/rehabilitación , Osteoporosis/tratamiento farmacológico , Fracturas Osteoporóticas/rehabilitación , Accidentes por Caídas/prevención & control , Anciano , Anciano de 80 o más Años , Conservadores de la Densidad Ósea/uso terapéutico , Femenino , Fracturas de Cadera/prevención & control , Hospitalización , Humanos , Masculino , Fracturas Osteoporóticas/prevención & control , Prevención Secundaria
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