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2.
Hong Kong Med J ; 29(3): 278-280, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37349146
3.
Hong Kong Med J ; 29(1): 88-90, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36810247
5.
Osteoarthritis Cartilage ; 30(2): 302-314, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34767957

RESUMO

OBJECTIVE: In knee cartilage from patients with osteoarthritis (OA), both preserved cartilage and damaged cartilage are observed. In this study, we aim to compare preserved with damaged cartilage to identify the molecule(s) that may be responsible for the mechanical loading-induced differences within cartilage degradation. METHODS: Preserved and damaged cartilage were harvested from the same OA knee joint. RNA Sequencing was performed to examine the transcriptomic differences between preserved and damaged cartilage cells. Estrogen receptor-α (ERα) was identified, and its function of was tested through gene knockin and knockout. The role of ERα in mediating chondrocyte response to mechanical loading was examined via compression of chondrocyte-laded hydrogel in a strain-controlled manner. Findings from the studies on human samples were verified in animal models. RESULTS: Level of estrogen receptor α (ERα) was significantly reduced in damaged cartilage compared to preserved cartilage, which were observed in both human and mice samples. Knockdown of ESR1, the gene encoding ERα, resulted in an upregulation of senescence- and OA-relevant markers in chondrocytes. Conversely, knockin of ESR1 partially reversed the osteoarthritic and senescent phenotype of OA chondrocytes. Using a three-dimensional (3D) culture model, we demonstrated that mechanical overload significantly suppressed ERα level in chondrocytes with concomitant upregulation of osteoarthritic phenotype. When ESR1 expression was suppressed, mechanical loading enhanced hypertrophic and osteogenic transition. CONCLUSION: Our study demonstrates a new estrogen-independent role of ERα in mediating chondrocyte phenotype and its response to mechanical loading, and suggests that enhancing ERα level may represent a new method to treat osteoarthritis.


Assuntos
Condrócitos/fisiologia , Receptor alfa de Estrogênio/fisiologia , Osteoartrite do Joelho/patologia , Suporte de Carga/fisiologia , Animais , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo
6.
Phys Rev Lett ; 127(18): 186001, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34767414

RESUMO

Understanding the mechanisms of proton energy deposition in matter and subsequent damage formation is fundamental to radiation science. Here we exploit the picosecond (10^{-12} s) resolution of laser-driven accelerators to track ultrafast solvation dynamics for electrons due to proton radiolysis in liquid water (H_{2}O). Comparing these results with modeling that assumes initial conditions similar to those found in photolysis reveals that solvation time due to protons is extended by >20 ps. Supported by magnetohydrodynamic theory this indicates a highly dynamic phase in the immediate aftermath of the proton interaction that is not accounted for in current models.

8.
10.
Phys Rev E ; 101(5-1): 053210, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32575346

RESUMO

We present an in-depth analysis of an ultrafast electron trajectory type that produces attosecond electromagnetic pulses in both the reflected and forward directions during normal incidence, relativistic laser-plasma interactions. Our particle-in-cell simulation results show that for a target which is opaque to the frequency of the driving laser pulse the emission trajectory is synchrotronlike but differs significantly from the previously identified figure-eight type which produces bright attosecond bursts exclusively in the reflected direction. The origin and characteristics of this trajectory type are explained in terms of the driving electromagnetic fields, the opacity of the plasma, and the conservation of canonical momentum.

11.
Support Care Cancer ; 28(8): 3503-3515, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31960125

RESUMO

BACKGROUND: Recent changes to the legal status of marijuana in Canada warrant a review of the information that patients and families are accessing online regarding the role of cannabis in cancer. The aims of the current research were to identify the quality of literature available online as well as the themes, and opinion (i.e., pro-, neutral, or anti-cannabis) of online articles. METHODS: Searches were conducted using three primary search engines: Google, Yahoo, and DuckDuckGo. Articles were assessed for quality based on a modified scale for evaluating online sources. Content of all unique articles was coded using a qualitative thematic methodology in a line-by-line fashion. Codes were clustered to determine themes within articles. Finally, opinions were determined by examining all articles in a line-by-line fashion. Each statement was coded as either pro-cannabis (positive) or anti-cannabis (negative). RESULTS: We found most articles were authored by journalists (39.4%) and MDs (14.1%) and published as news (35.2%) or web articles (28.2%). The content of articles focused on four themes: the reasons for and against cannabis use; the opinions of health care providers; the restrictions placed by governing bodies and the need for additional research, education, and standardization. Article opinions were neutral-pro-cannabis. CONCLUSIONS: Health care providers should be aware that the overall quality of information found online is considered "satisfactory." The majority of articles present a pro-cannabis opinion.


Assuntos
Internet , Uso da Maconha , Maconha Medicinal , Neoplasias/terapia , Educação de Pacientes como Assunto/métodos , Canadá , Criança , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Comportamento de Busca de Informação , Armazenamento e Recuperação da Informação , Uso da Maconha/legislação & jurisprudência , Maconha Medicinal/administração & dosagem , Maconha Medicinal/efeitos adversos , Cuidados Paliativos/métodos
13.
Phys Rev Lett ; 121(15): 154801, 2018 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-30362794

RESUMO

Controlling the parameters of a laser plasma accelerated electron beam is a topic of intense research with a particular focus placed on controlling the injection phase of electrons into the accelerating structure from the background plasma. An essential prerequisite for high-quality beams is dark-current free acceleration (i.e., no electrons accelerated beyond those deliberately injected). We show that small-scale density ripples in the background plasma are sufficient to cause the uncontrolled (self-)injection of electrons. Such ripples can be as short as ∼50 µm and can therefore not be resolved by standard interferometry. Background free injection with substantially improved beam characteristics (divergence and pointing) is demonstrated in a gas cell designed for a controlled gas flow. The results are supported by an analytical theory as well as 3D particle in cell simulations.

14.
Hong Kong Med J ; 24(4): 378-383, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30065125

RESUMO

INTRODUCTION: In Hong Kong, persons in custody receive primary medical care within the institutions of the Correctional Services Department (CSD). However, for psychiatric care, persons in custody must attend specialist out-patient clinics (SOPCs), which may cause embarrassment and stigmatisation. The aim of this interventional pilot study was to compare teleconsultations with face-to-face consultations for a group of stable Chinese psychiatric out-patients in custody. METHODS: A total of 86 stable Chinese male out-patients in custody were recruited for psychiatric teleconsultations. They were compared with 249 age-matched Chinese male out-patients in custody attending standard face-to-face psychiatric consultations at other SOPCs. The two groups had comparable baseline characteristics including age, education level, and 12-item Chinese General Health Questionnaire (C-GHQ-12) score. A satisfaction survey of patients towards the teleconsultation was also carried out. RESULTS: Compared with the face-to-face consultation group, the teleconsultation group showed a significantly better result in the difference in C-GHQ-12 scores before and after consultations (P=0.023). The correlation between the first and second teleconsultations also showed a moderate positive relationship (r=0.309). The satisfaction survey showed a favourable response to teleconsultations. No significant adverse events were identified for the teleconsultation group. CONCLUSIONS: The results suggest that teleconsultations are a sustainable and safe alternative to face-to-face consultations for stable Chinese psychiatric out-patients in custody.


Assuntos
Transtornos Mentais/terapia , Pacientes Ambulatoriais/psicologia , Prisioneiros/psicologia , Consulta Remota/métodos , Adulto , Hong Kong , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Inquéritos e Questionários
15.
Phys Rev Lett ; 120(7): 074801, 2018 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-29542949

RESUMO

We report on the experimental studies of laser driven ion acceleration from a double-layer target where a near-critical density target with a few-micron thickness is coated in front of a nanometer-thin diamondlike carbon foil. A significant enhancement of proton maximum energies from 12 to ∼30 MeV is observed when a relativistic laser pulse impinges on the double-layer target under linear polarization. We attributed the enhanced acceleration to superponderomotive electrons that were simultaneously measured in the experiments with energies far beyond the free-electron ponderomotive limit. Our interpretation is supported by two-dimensional simulation results.

16.
Phys Rev Lett ; 119(18): 185002, 2017 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-29219555

RESUMO

We report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (≥1 T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of ε_{B}≈10^{-3} is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma for thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.

17.
Bone Joint Res ; 5(6): 225-31, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27313136

RESUMO

OBJECTIVE: Hip arthroscopy in the setting of hip dysplasia is controversial in the orthopaedic community, as the outcome literature has been variable and inconclusive. We hypothesise that outcomes of hip arthroscopy may be diminished in the setting of hip dysplasia, but outcomes may be acceptable in milder or borderline cases of hip dysplasia. METHODS: A systematic search was performed in duplicate for studies investigating the outcome of hip arthroscopy in the setting of hip dysplasia up to July 2015. Study parameters including sample size, definition of dysplasia, outcomes measures, and re-operation rates were obtained. Furthermore, the levels of evidence of studies were collected and quality assessment was performed. RESULTS: The systematic review identified 18 studies investigating hip arthroscopy in the setting of hip dysplasia, with 889 included patients. Criteria used by the studies to diagnose hip dysplasia and borderline hip dysplasia included centre edge angle in 72% of studies but the range of angles were quite variable. Although 89% of studies reported improved post-operative outcome scores in the setting of hip dysplasia, revision rates were considerable (14.1%), with 9.6% requiring conversion to total hip arthroplasty. CONCLUSION: The available orthopaedic literature suggests that although improved outcomes are seen in hip arthroscopy in the setting of hip dysplasia, there is a high rate of re-operation and conversion to total hip arthroplasty. Furthermore, the criteria used to define hip dysplasia vary considerably among published studies.Cite this article: M. Yeung, M. Kowalczuk, N. Simunovic, O. R. Ayeni. Hip arthroscopy in the setting of hip dysplasia: A systematic review. Bone Joint Res 2016;5:225-231. DOI: 10.1302/2046-3758.56.2000533.

18.
Am J Transplant ; 16(11): 3139-3149, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27265023

RESUMO

B cells play a central role in antibody-mediated rejection and certain autoimmune diseases. However, B cell-targeted therapy such as anti-CD20 B cell-depleting antibody (aCD20) has yielded mixed results in improving outcomes. In this study, we investigated whether an accelerated B cell reconstitution leading to aCD20 depletion resistance could account for these discrepancies. Using a transplantation model, we found that antigen-independent inflammation, likely through toll-like receptor (TLR) signaling, was sufficient to mitigate B cell depletion. Secondary lymphoid organs had a quicker recovery of B cells when compared to peripheral blood. Inflammation altered the pharmacokinetics (PK) and pharmacodynamics (PD) of aCD20 therapy by shortening drug half-life and accelerating the reconstitution of the peripheral B cell pool by bone marrow-derived B cell precursors. IVIG (intravenous immunoglobulin) coadministration also shortened aCD20 drug half-life and led to accelerated B cell recovery. Repeated aCD20 dosing restored B cell depletion and delayed allograft rejection, especially B cell-dependent, antibody-independent allograft rejection. These data demonstrate the importance of further clinical studies of the PK/PD of monoclonal antibody treatment in inflammatory conditions. The data also highlight the disconnect between B cell depletion on peripheral blood compared to secondary lymphoid organs, the deleterious effect of IVIG when given with aCD20 and the relevance of redosing of aCD20 for effective B cell depletion in alloimmunity.


Assuntos
Antígenos CD20/imunologia , Linfócitos B/imunologia , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto/imunologia , Inflamação/imunologia , Depleção Linfocítica , Rituximab/farmacologia , Animais , Feminino , Rejeição de Enxerto/etiologia , Transplante de Coração/efeitos adversos , Imunoglobulinas Intravenosas/administração & dosagem , Fatores Imunológicos/farmacologia , Inflamação/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
19.
Allergy ; 71(10): 1461-71, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27087129

RESUMO

BACKGROUND: The prevalence of allergic rhinitis is high, but the role of environmental factors remains unclear. We examined cohort-specific and combined associations of residential greenness with allergic rhinitis and aeroallergen sensitization based on individual data from Swedish (BAMSE), Australian (MACS), Dutch (PIAMA), Canadian (CAPPS and SAGE), and German (GINIplus and LISAplus) birth cohorts (n = 13 016). METHODS: Allergic rhinitis (doctor diagnosis/symptoms) and aeroallergen sensitization were assessed in children aged 6-8 years in six cohorts and 10-12 years in five cohorts. Residential greenness was defined as the mean Normalized Difference Vegetation Index (NDVI) in a 500-m buffer around the home address at the time of health assessment. Cohort-specific associations per 0.2 unit increase in NDVI were assessed using logistic regression models and combined in a random-effects meta-analysis. RESULTS: Greenness in a 500-m buffer was positively associated with allergic rhinitis at 6-8 years in BAMSE (odds ratio = 1.42, 95% confidence interval [1.13, 1.79]) and GINI/LISA South (1.69 [1.19, 2.41]) but inversely associated in GINI/LISA North (0.61 [0.36, 1.01]) and PIAMA (0.67 [0.47, 0.95]). Effect estimates in CAPPS and SAGE were also conflicting but not significant (0.63 [0.32, 1.24] and 1.31 [0.81, 2.12], respectively). All meta-analyses were nonsignificant. Results were similar for aeroallergen sensitization at 6-8 years and both outcomes at 10-12 years. Stratification by NO2 concentrations, population density, an urban vs rural marker, and moving did not reveal consistent trends within subgroups. CONCLUSION: Although residential greenness appears to be associated with childhood allergic rhinitis and aeroallergen sensitization, the effect direction varies by location.


Assuntos
Alérgenos/imunologia , Meio Ambiente , Características de Residência , Rinite Alérgica/epidemiologia , Rinite Alérgica/etiologia , Criança , Estudos de Coortes , Feminino , Humanos , Imunização , Masculino , Avaliação de Resultados da Assistência ao Paciente , Fatores de Risco
20.
Opt Express ; 24(3): 3127-36, 2016 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-26906877

RESUMO

Temporal overlapping of ultra-short and focussed laser pulses is a particularly challenging task, as this timescale lies orders of magnitude below the typical range of fast electronic devices. Here we present an optical technique that allows for the measurement of the temporal delay between two focussed and ultra-short laser pulses. This method is virtually applicable to any focussing geometry and relative intensity of the two lasers. Experimental implementation of this technique provides excellent quantitative agreement with theoretical expectations. The proposed technique will prove highly beneficial for high-power multiple-beam laser experiments.

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