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1.
Langmuir ; 39(8): 3142-3150, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36795954

RESUMO

The current synthesis methods of high-entropy alloy (HEA) thin-film coatings face huge challenges in facile preparation, precise thickness control, conformal integration, and affordability. These challenges are more specific and noteworthy for noble metal-based HEA thin films where the conventional sputtering methods encounter thickness control and high-cost issues (high-purity noble metal targets required). Herein, for the first time, we report a facile and controllable synthesis process of quinary HEA coatings consisting of noble metals (Rh, Ru, Pt, Pd, and Ir), by sequential atomic layer deposition (ALD) coupled with electrical Joule heating for post-alloying. Furthermore, the resulting quinary HEA thin film with a thickness of ∼50 nm and an atomic ratio of 20:15:21:18:27 shows promising potential as a platform for catalysis, exhibiting enhanced electrocatalytic hydrogen evolution reaction (HER) performances with lower overpotentials (e.g., from 85 to 58 mV in 0.5 M H2SO4) and higher stability (by retaining more than 92% of the initial current after 20 h with a current density of 10 mA/cm2 in 0.5 M H2SO4) than other noble metal-based structure counterparts in this work. The enhanced material properties and device performances are attributed to the efficient electron transfer of HEA with the increased number of active sites. This work not only presents RhRuPtPdIr HEA thin films as promising HER catalysts but also sheds light on controllable fabrication of conformal HEA-coated complex structures toward a broad range of applications.

2.
ACS Appl Mater Interfaces ; 14(46): 52279-52288, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36375117

RESUMO

Mesoporous silica nanoparticles have highly versatile structural properties that are suitable for a plethora of applications including catalysis, separation, and nanotherapeutics. We report a one-pot synthesis strategy that generates bimodal mesoporous silica nanoparticles via coassembly of a structure-directing Gemini surfactant (C16-3-16) with a tetraethoxysilane/(3-aminopropyl)triethoxysilane-derived sol additive. Synthesis temperature enables control of the nanoparticle shape, structure, and mesopore architecture. Variations of the aminosilane/alkylsilane molar ratio further enable programmable adjustments of hollow to core-shell and dense nanoparticle morphologies, bimodal pore sizes, and surface chemistries. The resulting Gemini-directed aminated mesoporous silica nanoparticles have excellent carbon dioxide adsorption capacities and antimicrobial properties against Escherichia coli. Our results provide an enhanced understanding of the structure formation of multiscale mesoporous inorganic materials that are desirable for numerous applications such as carbon sequestration, water remediation, and biomedical-related applications.


Assuntos
Nanopartículas , Dióxido de Silício , Dióxido de Silício/química , Prata , Dióxido de Carbono , Porosidade , Nanopartículas/química , Antibacterianos/farmacologia
3.
ACS Polym Au ; 2(1): 42-49, 2022 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-36855749

RESUMO

Block copolymer self-assembly-derived thin films provide direct access to two- and three-dimensional periodically ordered mesostructures as enablers for many nanotechnology applications. This report describes laser-annealing-induced disorder-order mesophase transitions of polystyrene-block-poly(ethylene oxide)/resol hybrid thin films over a range of laser temperatures (∼45 to 525 °C) and short dwell times (0.25 to 100 ms), revealing the non-equilibrium ordering and disordering kinetics and behaviors. We found that a combination of transient laser temperature of ∼275 °C and annealing dwell time of 100 ms provided the most optimal kinetic and thermodynamic control of the diffusivities of hybrid mesophases and photothermal-induced resol polymerization, yielding long-range ordered films resembling an in-plane body-centered cubic sphere morphology. A clear understanding of hybrid thin film mesophase self-assembly under non-equilibrium laser annealing could open new avenues to introduce novel chemistries and rapidly achieve nanoscale periodic order suitable for the patterning of complex structures, electronics, sensing, and emerging quantum materials.

4.
ACS Appl Mater Interfaces ; 13(30): 36117-36129, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34288649

RESUMO

We describe a versatile and scalable strategy toward long-range and periodically ordered mesoporous alumina (Al2O3) structures by evaporation-induced self-assembly of a structure-directing ABA triblock copolymer (F127) mixed with aluminum tri-sec-butoxide-derived sol additive. We found that the separate preparation of the alkoxide sol-gel reaction before mixing with the block copolymer enabled access to a relatively unexplored parameter space of copolymer-to-additive composition, acid-to-metal molar ratio, and solvent, yielding ordered mesophases of two-dimensional (2D) lamellar, hexagonal cylinder, and 3D cage-like cubic lattices, as well as multiscale hierarchical ordered structures from spinodal decomposition-induced macro- and mesophase separation. Thermal annealing in air at 900 °C yielded well-ordered mesoporous crystalline γ-Al2O3 structures and hierarchically porous γ-Al2O3 with 3D interconnected macroscale and ordered mesoscale pore networks. The ordered Al2O3 structures exhibited tunable pore sizes in three different length scales, <2 nm (micropore), 2-11 nm (mesopore), and 1-5 µm (macropore), as well as high surface areas and pore volumes of up to 305 m2/g and 0.33 cm3/g, respectively. Moreover, the resultant mesoporous Al2O3 demonstrated enhanced adsorption capacities of carbon dioxide and Congo red dye. Such hierarchically ordered mesoporous Al2O3 are well-suited for green environmental solutions and urban sustainability applications, for example, high-temperature solid adsorbents and catalyst supports for carbon dioxide sequestration, fuel cells, and wastewater separation treatments.

5.
Eur Spine J ; 30(9): 2670-2679, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34251572

RESUMO

PURPOSE: Oswestry Disability Index (ODI) was established by Fairbank in 1989 to assess functional disabilities in low back pain (LBP). It was last updated in 2019 as ODI version 2.1b (ODI AU_2.1b). ODI was first translated into Simplified Chinese Oswestry Disability Index (CODI) in 2008 by Lue. The construct validity, internal consistency, level of agreement and the floor and ceiling effects of CODI were found unclear by Yao in 2016. This study will verify how well the adapted Cantonese-Hong Kong Oswestry Disability Index version 2.1b (HKCODI) aligns with ODI AU_2.1b in the Southern Chinese population. METHODS: The translation of ODI AU_2.1b was performed according to guidelines from MAPI Research Trust and American Association of Orthopaedic Surgeons. Psychometric properties of HKCODI were tested statistically by Pearson's correlation, Cronbach's Alpha and Intraclass  Correlation  Coefficient (ICC). RESULTS: A total of 200 subjects (109 males, 91 females) aged from 15 to 85 (mean age = 58.91) with LBP scored from 3/10 to 10/10 in the Visual Analogue Scale (VAS) were recruited in the Occupational Therapy Department of a tertiary referral center. HKCODI demonstrated strong construct validity in comparing with Hong Kong Roland-Morris Disability Questionnaire (HKRMDQ) (r = 0.666, p = 0.000), Short Form Health Survey (SF-36)  Physical Composite Summary (- 0.700, p = 0.000) and VAS (0.487, p = 0.000). Excellent internal consistency and test-retest reliability were confirmed with Cronbach's Alpha of 0.997 and ICC of 0.993 at 95% confidence level. CONCLUSION: Cross-cultural adaptation of ODI AU_2.1b has been translated and validated as   HKCODI and Item-8 (Sex Life) was suggested to skip for patient older than 60. HKCODI is a fully self-administered and highly reliable tool in assessing the functional disability of patients with LBP in the Southern Chinese population.


Assuntos
Comparação Transcultural , Avaliação da Deficiência , Feminino , Hong Kong , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Inquéritos e Questionários
6.
Langmuir ; 36(36): 10803-10810, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32787003

RESUMO

This report describes a simple one-pot soft-templating and ammonolysis-free approach to synthesize mesoporous crystalline titanium oxynitride by combining block copolymer-directed self-assembly with metal sol and urea precursors. The Pluronic F127 triblock copolymer was employed to structure-direct titanium-oxo-acetate sol nanoparticles and urea-formaldehyde into ordered hybrid mesostructured monoliths. The hybrid composites were directly converted into mesoporous crystalline titanium oxynitride and retained macroscale monolithic integrity up to 800 °C under nitrogen. Notably, the urea-formaldehyde additive provided nitrogen and rigid support to the inorganic mesostructure during crystallization. The resultant mesoporous titanium oxynitride exhibited good electrochemical catalytic activity toward hydrogen evolution reaction in 1 M KOH aqueous medium under applied bias. Our results suggest an inexpensive and safe pathway to generate ordered mesoporous crystalline metal oxynitride structures suitable for catalyst and energy-storage applications.

7.
Artigo em Inglês | MEDLINE | ID: mdl-32331399

RESUMO

The present paper reviews available background information for studying multiple stressor effects of radon (222Rn) and phthalates in children and provides insights on future directions. In realistic situations, living organisms are collectively subjected to many environmental stressors, with the resultant effects being referred to as multiple stressor effects. Radon is a naturally occurring radioactive gas that can lead to lung cancers. On the other hand, phthalates are semi-volatile organic compounds widely applied as plasticizers to provide flexibility to plastic in consumer products. Links of phthalates to various health effects have been reported, including allergy and asthma. In the present review, the focus on indoor contaminants was due to their higher concentrations and to the higher indoor occupancy factor, while the focus on the pediatric population was due to their inherent sensitivity and their spending more time close to the floor. Two main future directions in studying multiple stressor effects of radon and phthalates in children were proposed. The first one was on computational modeling and micro-dosimetric studies, and the second one was on biological studies. In particular, dose-response relationship and effect-specific models for combined exposures to radon and phthalates would be necessary. The ideas and methodology behind such proposed research work are also applicable to studies on multiple stressor effects of collective exposures to other significant airborne contaminants, and to population groups other than children.


Assuntos
Poluentes Radioativos do Ar , Poluição do Ar em Ambientes Fechados , Exposição Ambiental , Plastificantes , Radônio , Estresse Fisiológico , Poluentes Radioativos do Ar/toxicidade , Asma , Criança , Pisos e Cobertura de Pisos , Humanos , Hipersensibilidade , Plastificantes/toxicidade , Radônio/toxicidade
8.
Adv Mater ; 32(21): e1908362, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32270557

RESUMO

Despite extensive studies on mesoporous silica since the early 1990s, the synthesis of two-dimensional (2D) silica nanostructures remains challenging. Here, mesoporous silica is synthesized at an interface between two immiscible solvents under conditions leading to the formation of 2D superstructures of silica cages, the thinnest mesoporous silica films synthesized to date. Orientational correlations between cage units increase with increasing layer number controlled via pH, while swelling with oil and mixed surfactants increase micelle size dispersity, leading to complex clathrate type structures in multilayer superstructures. The results suggest that a three-dimensional (3D) crystallographic registry within cage-like superstructures emerges as a result of the concerted 3D co-assembly of the organic and inorganic components. Mesoporous 2D superstructures can be fabricated over macroscopic film dimensions and stacked on top of each other. The realization of previously inaccessible mesoporous silica heterostructures with separation or catalytic properties unachievable via conventional bulk syntheses is envisioned.

9.
Curr Oncol ; 25(3): e193-e199, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29962845

RESUMO

Malnutrition is a frequent manifestation in patients with head-and-neck cancer undergoing radiation therapy and a major contributor to morbidity and mortality. Thus, body composition is an important component of an overall evaluation of nutrition in cancer patients. Malnutrition is characterized by weight loss, loss of muscle mass, changes in cell membrane integrity, and alterations in fluid balance. Bioelectrical impedance analysis is a method to analyze body composition and includes parameters such as intracellular water content, extracellular water content, and cell membrane integrity in the form of a phase angle (Φ). Bioelectrical impedance analysis has consistently been shown to have prognostic value with respect to mortality and morbidity in patients undergoing chemotherapy. The goal of the present study was to evaluate the relationship between Φ, time, intracellular water content, and weight for head-and-neck cancer patients undergoing radiotherapy. The results demonstrate that Φ decreases with time and increases with intracellular water content and weight.


Assuntos
Impedância Elétrica/uso terapêutico , Neoplasias de Cabeça e Pescoço/radioterapia , Desnutrição/etiologia , Adulto , Idoso , Peso Corporal , Humanos , Masculino , Desnutrição/patologia , Pessoa de Meia-Idade , Avaliação Nutricional , Prognóstico
10.
Hong Kong Med J ; 24(1): 25-31, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29326400

RESUMO

INTRODUCTION: Angiosarcoma is a rare aggressive sarcoma that occurs mostly in the skin of the head and neck in the elderly population. The optimal management is dubious and most studies are from Caucasian populations. We aimed to examine the treatment and outcome of this disease in Chinese patients. METHODS: Data of patients with histopathologically verified cutaneous angiosarcoma of the head and neck during December 1997 to September 2016 were retrieved from our hospital cancer registry. The demographic data, clinicopathological information, modality of treatment, and outcomes were reviewed. RESULTS: During the study period, 17 Chinese patients were treated. Their median age was 81 years. The tumours were present in the scalp only (n=11), face only (n=4), or both scalp and face (n=2). Only two patients had distant metastases. The modalities of treatment were surgery (n=6), surgery and adjuvant radiotherapy (n=1), palliative radiotherapy (n=5), or palliative chemotherapy (n=3). The remaining two patients refused any treatment initially. Of the seven patients treated surgically, there were four local and two regional recurrences. The median time to relapse was 7.5 months. Overall, 16 patients had died; causes of death were disease-related in 12 whereas four other patients died of inter-current illnesses. One patient was still living with the disease. The median overall survival was 11.1 months and the longest overall survival was 42 months. CONCLUSION: The outcome of angiosarcoma in our series is poor. A high index of suspicion is mandatory for prompt diagnosis. Adjuvant radiotherapy is recommended following surgery. The benefit and role of systemic treatment in various combinations with surgery or radiotherapy require further study.


Assuntos
Face/patologia , Neoplasias Faciais/terapia , Hemangiossarcoma/terapia , Couro Cabeludo/patologia , Neoplasias Cutâneas/terapia , Idoso , Idoso de 80 Anos ou mais , Institutos de Câncer , Causas de Morte , Terapia Combinada , Neoplasias Faciais/mortalidade , Feminino , Hemangiossarcoma/mortalidade , Hong Kong , Humanos , Masculino , Invasividade Neoplásica/patologia , Recidiva Local de Neoplasia/patologia , Estadiamento de Neoplasias , Radioterapia Adjuvante , Estudos Retrospectivos , Neoplasias Cutâneas/mortalidade
12.
Hong Kong Med J ; 23(4): 387-94, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28649094

RESUMO

Pregnancy-associated breast cancer is the most common malignancy during pregnancy with an expected rise in incidence. The belief in the need for termination of pregnancy and that chemotherapy is contra-indicated during pregnancy is challenged by recent evidence. Patients can consider breast-conserving surgery and sentinel lymph node biopsy with acceptably low fetal risk from radiation exposure. A range of chemotherapeutics is possible in the second trimester in terms of drug class and frequency. Hormonal therapy and monoclonal antibody therapy are contra-indicated during pregnancy and lactation. Fetal outcome after in-utero exposure to chemotherapy appears similar to that in a non-pregnant population. Future pregnancy, in most situations, does not appear to be contra-indicated but a multidisciplinary and patient-centred approach is recommended. Fertility preservation techniques are also being developed with reported success and consequent pregnancies.


Assuntos
Neoplasias da Mama/terapia , Gerenciamento Clínico , Complicações Neoplásicas na Gravidez/terapia , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Feminino , Humanos , Recém-Nascido , Mastectomia Segmentar/efeitos adversos , Exposição Materna/efeitos adversos , Gravidez , Biópsia de Linfonodo Sentinela/efeitos adversos
13.
Artigo em Inglês | MEDLINE | ID: mdl-27132979

RESUMO

Oncology services do not routinely assess broader needs of older people with cancer. This study evaluates a comprehensive geriatric assessment and comorbidity screening questionnaire (CGA-GOLD) covering evidence-based domains and quality of life (EORTC-QLQ-C30). Patients aged 65+ attending oncology services were recruited into (1) Observational cohort (completed CGA-GOLD, received standard oncology care), (2) Intervention cohort (responses categorised 'low-risk', 'high-risk', 'possible need' by geriatricians). N = 417 observational patients (1002 invited by post, 418 consented, age 73.9 ± 5.4) completed CGA-GOLD in 11.7 ± 7.9 min, 86.3% required no assistance, 3.1% overall missing responses. Multiple problems reported: hypertension (18.1%), diabetes (16.9%), dyspnoea on flat surfaces (27.6%), polypharmacy (46%), difficulty walking (14.9%), fatigue (40.5%), living alone (30.9%), social isolation (11.2%), recent functional dependence (27.8%), urinary incontinence (21.4%), falls (13.3%). 237/239 intervention patients completed CGA-GOLD and consecutive subsets examined. The doctor and nurse specialist independently identified same need level in 87.3% (high inter-rater reliability kappa = 0.80), taking 1-2 min per questionnaire. Need level remained unchanged following hospital notes review against responses in 90% (75/83). 'Possible need' patients were telephoned with change in 29% (16/55) to low-risk and none to high-risk, confirming high need was not being missed. CGA-GOLD screening questionnaire was acceptable to older patients, feasibly administered in NHS cancer services, described comorbidities, CGA and QOL needs, and reliably identified higher risk patients requiring further input for optimal cancer treatment.


Assuntos
Avaliação Geriátrica/métodos , Avaliação das Necessidades , Neoplasias/terapia , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Comorbidade , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiologia , Dispneia/diagnóstico , Dispneia/epidemiologia , Fadiga/diagnóstico , Fadiga/epidemiologia , Feminino , Humanos , Hipertensão/diagnóstico , Hipertensão/epidemiologia , Londres/epidemiologia , Masculino , Programas de Rastreamento/métodos , Limitação da Mobilidade , Neoplasias/epidemiologia , Polimedicação , Características de Residência , Medição de Risco , Isolamento Social , Inquéritos e Questionários , Incontinência Urinária/diagnóstico , Incontinência Urinária/epidemiologia
14.
Hong Kong Med J ; 22(3): 202-9, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27022189

RESUMO

INTRODUCTION: Breast cancer is the leading cause of death of Hong Kong women with increasing incidence. This study aimed to determine any prognostic differences between screen-detected and self-detected cases of breast cancer in a cohort of Hong Kong patients. METHODS: This was a case series with internal comparison carried out in a private hospital in Hong Kong. Approximately 3000 cases of Chinese patients diagnosed with ductal carcinoma in situ or invasive breast cancer were reviewed. RESULTS: The screen-detected group showed better pathological characteristics than the self-detected group. Number of lymph nodes involved, invasive tumour size, and tumour grade were more favourable in the screen-detected group. There was also a lower proportion of patients with pure invasive ductal carcinoma and mastectomy in the screen-detected group. CONCLUSION: This study provides indirect evidence that women in the local population may gain clinical benefit from regular breast cancer screening. The findings need to be validated in a representative population of Hong Kong women.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/patologia , Autoexame de Mama , Carcinoma Intraductal não Infiltrante/diagnóstico por imagem , Carcinoma Intraductal não Infiltrante/patologia , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Neoplasias da Mama/terapia , Carcinoma Intraductal não Infiltrante/terapia , Detecção Precoce de Câncer/estatística & dados numéricos , Feminino , Hong Kong , Humanos , Modelos Logísticos , Linfonodos/patologia , Mamografia , Mastectomia , Pessoa de Meia-Idade , Análise Multivariada , Prognóstico , Estudos Retrospectivos , Adulto Jovem
15.
Am J Transplant ; 16(4): 1053-69, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26602545

RESUMO

The mononuclear phagocyte system (MPS) comprises monocytes, macrophages and dendritic cells (DCs). Over the past few decades, classification of the cells of the MPS has generated considerable controversy. Recent studies into the origin, developmental requirements and function of MPS cells are beginning to solve this problem in an objective manner. Using high-resolution genetic analyses and fate-mapping studies, three main mononuclear phagocyte lineages have been defined, namely, macrophage populations established during embryogenesis, monocyte-derived cells that develop during adult life and DCs. These subsets and their diverse subsets have specialized functions that are largely conserved between species, justifying the introduction of a new, universal scheme of nomenclature and providing the framework for therapeutic manipulation of immune responses in the clinic. In this review, we have commented on the implications of this novel MPS classification in solid organ transplantation.


Assuntos
Sistema Fagocitário Mononuclear/imunologia , Transplante de Órgãos , Adulto , Animais , Humanos
16.
J Comp Neurol ; 524(6): 1193-207, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26355791

RESUMO

The New World marmoset monkey (Callithrix jacchus) has a relatively short gestational period compared with other primates but possesses a retina at a similar stage of maturation by birth. Previous studies have highlighted that the complex fovea of the marmoset undergoes a more rapid postnatal development in comparison with the Macaca monkey, reaching a mature stage earlier than these species. In this current study, we examined the prenatal proliferation profile of cells in the entire retina employing the thymidine analogs and also determined their phenotype by double-label immunocytochemistry using type-specific markers. Akin to other primate species, we demonstrate a centroperipheral gradient in the emergence of both neurons and Müller glia with cones, ganglion cells, and horizontal cells generated first in the fovea at fetal day (Fd)70-74 and with the last generated at the retinal edge at Fd115. Rods, bipolar cells, amacrine cells, displaced amacrine cells, and Müller glia were generated between Fd76 and Fd135 along the same gradient. Similar to foveal development, marmoset neuronal generation was rapid, only taking 51% of gestation whereas in Macaca this takes 81%.


Assuntos
Neurogênese/fisiologia , Células Fotorreceptoras Retinianas Cones/fisiologia , Células Fotorreceptoras Retinianas Bastonetes/fisiologia , Fatores Etários , Animais , Callithrix , Feminino , Masculino , Retina/citologia , Retina/crescimento & desenvolvimento , Fatores de Tempo
17.
Can J Gastroenterol Hepatol ; 29(2): 72-6, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25803016

RESUMO

BACKGROUND: The cost of liver biopsy (LB) is publicly funded in British Columbia, while the cost of transient elastography (FibroScan [FS], Echosens, France) is not. Consequently, there is regional variation regarding FS access and monitoring of liver disease progression. OBJECTIVE: To evaluate patient preference for FS versus LB and to assess the willingness to self-pay for FS. METHODS: Questionnaires were distributed in clinic and via mail to LB-experienced and LB-naive patients who underwent FS at Vancouver General Hospital, Vancouver, British Columbia. RESULTS: The overall response rate was 76%. Of the 422 respondents, 205 were LB-experienced. The mean age was 53.5 years, 50.2% were male, 54.7% were Caucasian, 38.2% had hepatitis C and 26.3% had an annual household income >$75,000. Overall, 95.4% of patients preferred FS to LB. FS was associated with greater comfort than LB, with the majority reporting no discomfort during FS (84.1% versus 7.8% for LB), no discomfort after (96.2% versus 14.6% LB) and no feelings of anxiety after FS explanation (78.2% versus 12.7% LB). FS was also associated with greater speed, with the majority reporting short test duration (97.2% versus 48.3% LB) and short wait for the test result (95.5% versus 30.2% LB). Most (75.3%) respondents were willing to self-pay for FS, with 26.3% willing to pay $25 to $49. Patients with unknown liver disease preferred LB (OR [FS preference] 0.20 [95% CI 0.07 to 0.53]). CONCLUSIONS: FS was the preferred method of assessing liver fibrosis among patients, with the majority willing to self-pay. To ensure consistency in access, provincial funding for FS is needed. However, LB remains the procedure of choice for individuals with an unknown diagnosis.


Assuntos
Biópsia/psicologia , Técnicas de Imagem por Elasticidade/psicologia , Honorários e Preços , Financiamento Pessoal , Cirrose Hepática/diagnóstico , Preferência do Paciente/psicologia , Adulto , Biópsia/economia , Colúmbia Britânica , Técnicas de Imagem por Elasticidade/economia , Feminino , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade , Preferência do Paciente/economia , Inquéritos e Questionários
18.
J Am Chem Soc ; 137(6): 2350-8, 2015 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-25625616

RESUMO

Methylammonium lead halide perovskite solar cells continue to excite the research community due to their rapidly increasing performance which, in large part, is due to improvements in film morphology. The next step in this progression is control of the crystal morphology which requires a better fundamental understanding of the crystal growth. In this study we use in situ X-ray scattering data to study isothermal transformations of perovskite films derived from chloride, iodide, nitrate, and acetate lead salts. Using established models we determine the activation energy for crystallization and find that it changes as a function of the lead salt. Further analysis enabled determination of the precursor composition and showed that the primary step in perovskite formation is removal of excess organic salt from the precursor. This understanding suggests that careful choice of the lead salt will aid in controlling crystal growth, leading to superior films and better performing solar cells.


Assuntos
Compostos de Cálcio/química , Halogênios/química , Compostos Inorgânicos/química , Compostos Orgânicos/química , Óxidos/química , Titânio/química , Ânions , Cristalização , Cinética
19.
Brain Struct Funct ; 220(1): 351-60, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24173617

RESUMO

Retrograde transneuronal degeneration (RTD) of retinal ganglion cells and dorsal lateral geniculate (LGN) neurons are well described following a lesion of the primary visual cortex (V1) in both Old World monkeys and humans. Based on previous studies of New World monkeys and prosimians, it was suggested that these species displayed no RTD following a lesion of V1. In this study of the New World marmoset monkey, 1 year after a unilateral V1 lesion either in adults or at 14 days after birth, we observed ~20 % ganglion cell (GC) loss in adult but ~70 % in infants. This finding is similar to the RTD previously described for Old World Macaca monkeys. Furthermore, in infants we find a similar amount of RTD at 3 weeks and 1 year following lesion, demonstrating that RTD is very rapid in neonates. This highlights the importance of trying to prevent the rapid onset of RTD following a lesion of V1 in early life as a strategy for improved functional recovery. Despite differences in GC loss, there was little difference between LGN degeneration in infant versus adult lesions. A wedge on the horizontal meridian corresponding to the LGN foveal representation revealed extensive neuronal loss. Retinal afferent input was labeled by cholera toxin B subunit. Input to the degenerated parvocellular layers was difficult to detect, while input to magnocellular and koniocellular layers was reduced but still apparent. Our demonstration that the New World marmoset monkey shares many of the features of neuroplasticity with Old World Macaca monkeys and humans emphasizes the opportunity and benefit of marmosets as models of visual cortical injury.


Assuntos
Lesões Encefálicas/complicações , Lesões Encefálicas/patologia , Corpos Geniculados/patologia , Degeneração Neural/etiologia , Retina/patologia , Córtex Visual/patologia , Animais , Calbindina 1/metabolismo , Calbindina 2/metabolismo , Callithrix , Proteínas de Neurofilamentos/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Parvalbuminas/metabolismo , Fosfopiruvato Hidratase/metabolismo , Vias Visuais/patologia , Ácido gama-Aminobutírico/metabolismo
20.
Placenta ; 35(8): 645-54, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24951174

RESUMO

INTRODUCTION: Banking of high-quality placental tissue specimens will enable biomarker discovery and molecular studies on diseases involving placental dysfunction. Systematic studies aimed at developing feasible standardized methodology for placental collection in a typical clinical setting are lacking. METHODS: To determine the acceptable timeframe for placental collection, we collected multiple samples from first and third trimester placentas at serial timepoints in a 2-h window after delivery, simultaneously comparing the traditional snap-freeze technique to commercial solutions designed to preserve RNA (RNAlater™), and DNA (DNAgard(®)). The performance of RNAlater for preserving DNA was also tested. Nucleic acid quality was assessed by determining the RNA integrity number (RIN) and genome-wide microarray profiling for gene expression and DNA methylation. RESULTS: We found that samples collected in RNAlater had higher and more consistent RINs compared to snap-frozen tissue. Similar RINs were obtained for tissue collected in RNAlater as large (1 cm(3)) and small (∼0.1 cm(3)) pieces. RNAlater appeared to better stabilize the time zero gene expression profile compared to snap-freezing for first trimester placenta. DNA methylation profiles remained quite stable over a 2 h time period after removal of the placenta from the uterus, with DNAgard being superior to other treatments. DISCUSSION AND CONCLUSION: The collection of placental samples in RNAlater and DNAgard is simple, and eliminates the need for liquid nitrogen or a freezer on-site. Moreover, the quality of the nucleic acids and the resulting data from samples collected in these preservation solutions is higher than samples collected using the snap-freeze method and easier to implement in busy clinical environments.


Assuntos
Placenta , Manejo de Espécimes , Bancos de Tecidos , Metilação de DNA , Feminino , Perfilação da Expressão Gênica , Estudo de Associação Genômica Ampla , Genômica , Humanos , Gravidez , Primeiro Trimestre da Gravidez , Terceiro Trimestre da Gravidez , RNA Mensageiro/análise
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