Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 23
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Phys Chem Chem Phys ; 17(3): 2137-42, 2015 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-25482160

RESUMO

We have correlated the elemental composition with the structure of multi-wall carbon nanotubes synthesised with nitrogen and phosphorus containing precursors and identified two chemically distinct dominant morphologies. The first type are cone-structured tubes and the second are nanotubes with fewer walls which can accommodate N2 gas along their inner channel and contain up to ten times more nitrogen than the cone-structured nanotubes. Phosphorus was present in the catalyst particles but was not detected within the walls of either type of nanotube. Elemental analysis combined with in situ electrical measurements has allowed us to monitor the evolution of the doped nanotubes when current is passed. The N2 gas becomes bonded immediately when current flows and the gas-containing nanotubes restructure more easily than the cone-structured ones. Since the inclusion of heteroatoms in multi-wall carbon nanotubes is generally inhomogeneous, understanding the distribution of elements across the sample is an important step towards the optimization of devices including gas sensors and components in electrical applications.

2.
Support Care Cancer ; 23(1): 253-61, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25115893

RESUMO

BACKGROUND: Preventing and managing chemotherapy-induced nausea and vomiting (CINV) remain important goals. The objective of the Pan Australasian chemotherapy-induced emesis burden of illness (PrACTICE) study was to describe the incidence of CINV after highly or moderately emetogenic chemotherapy (HEC or MEC) for cancer in current clinical practice in Australia and five Asian countries (China, India, Singapore, South Korea, and Taiwan). STUDY DESIGN: This prospective, observational study of CINV was conducted at 31 sites in these six countries from August 2011 through September 2012 and enrolled male and female adult patients (≥18 years of age) naïve to HEC and MEC who were scheduled to receive at least two cycles of single-day chemotherapy. The primary effectiveness endpoint was complete response, defined as no vomiting or use of rescue therapy, during chemotherapy cycle 1 in the overall phase (0-120 h), acute phase (0-24 h), and delayed phase (>24-120 h). Study outcomes were analyzed descriptively. Primary outcomes, CINV incidence, and treatment patterns (chemotherapy, CINV prophylaxis, rescue medication prescription, and rescue medication use) were assessed by phase (overall, acute, delayed), by cycle (as appropriate), within and across countries, and by level of chemotherapy emetogenicity (HEC vs. MEC). The impact of CINV in cycle 1 on CINV in cycle 2 was analyzed for all patients with evaluable data for cycle 2. No site-specific analyses were performed. The remainder of this special series of papers reports on the results of this study.


Assuntos
Antieméticos/uso terapêutico , Náusea/tratamento farmacológico , Vômito/tratamento farmacológico , Adulto , Idoso , Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Austrália/epidemiologia , China/epidemiologia , Efeitos Psicossociais da Doença , Feminino , Humanos , Incidência , Índia/epidemiologia , Quimioterapia de Indução , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Náusea/epidemiologia , Neoplasias/tratamento farmacológico , Estudos Prospectivos , República da Coreia/epidemiologia , Inquéritos e Questionários , Vômito/induzido quimicamente , Vômito/epidemiologia
3.
Microsc Microanal ; 20(4): 1053-9, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24758771

RESUMO

Hexagonal boron nitride (hBN) is a promising material for a range of applications including deep-ultraviolet light emission. Despite extensive experimental studies, some fundamental aspects of hBN remain unknown, such as the type of stacking faults likely to be present and their influence on electronic properties. In this paper, different stacking configurations of hBN are investigated using CASTEP, a pseudopotential density functional theory code. AB-b stacking faults, in which B atoms are positioned directly on top of one another while N atoms are located above the center of BN hexagons, are shown to be likely in conventional AB stacked hBN. Bandstructure calculations predict a single direct bandgap structure that may be responsible for the discrepancies in bandgap type observed experimentally. Calculations of the near edge structure showed that different stackings of hBN are distinguishable using measurements of core-loss edges in X-ray absorption and electron energy loss spectroscopy. AB stacking was found to best reproduce features in the experimental B and N K-edges. The calculations also show that splitting of the 1s to π* peak in the B K-edge, recently observed experimentally, may be accounted for by the presence of AB-b stacking faults.

4.
J Prim Health Care ; 14(1): 43-47, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35417336

RESUMO

Background and context The transgender community experiences high levels of mental distress. In the Canterbury region of New Zealand, transgender care was fragmented and there were gaps in service provision. Assessment of problem In 2019, a working group co-designed a model to coordinate and improve health care for the Canterbury transgender community. Their aim was to co-design and implement a comprehensive system for transgender health care that filled any existing gaps. Results A need was identified for support in the community for transgender patients with mild to moderate mental health needs who did not meet the threshold for referral to secondary care. Strategies for improvement Psychological packages of care were put in place in the community for transgender patients with mental health needs. In the first 9 months of the initiative, 85 patients received a package of care. Lessons This community-based model was well received by the community. Data analysis did not demonstrate a statistically significant reduction in depression and anxiety, but it did show a significant reduction in stress. Some further improvement opportunities existed, including shifting to a peer worker model and changing the evaluation tool.


Assuntos
Pessoas Transgênero , Transtornos de Ansiedade , Humanos , Saúde Mental , Nova Zelândia , Encaminhamento e Consulta , Pessoas Transgênero/psicologia
5.
Nat Commun ; 13(1): 6070, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36241622

RESUMO

The solid electrolyte interphase (SEI) that forms on Li-ion battery anodes is critical to their long-term performance, however observing SEI formation processes at the buried electrode-electrolyte interface is a significant challenge. Here we show that operando soft X-ray absorption spectroscopy in total electron yield mode can resolve the chemical evolution of the SEI during electrochemical formation in a Li-ion cell, with nm-scale interface sensitivity. O, F, and Si K-edge spectra, acquired as a function of potential, reveal when key reactions occur on high-capacity amorphous Si anodes cycled with and without fluoroethylene carbonate (FEC). The sequential formation of inorganic (LiF) and organic (-(C=O)O-) components is thereby revealed, and results in layering of the SEI. The addition of FEC leads to SEI formation at higher potentials which is implicated in the rapid healing of SEI defects and the improved cycling performance observed. Operando TEY-XAS offers new insights into the formation mechanisms of electrode-electrolyte interphases and their stability for a wide variety of electrode materials and electrolyte formulations.

6.
Phys Chem Chem Phys ; 12(2): 433-41, 2010 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-20023821

RESUMO

One-dimensional nanostructures based on the Mo-S-I system have recently aroused a lot of interest as a viable alternative to the ubiquitous carbon nanotube due to their uniform structure and electronic properties for a given composition. Previous research on the Mo(6)S(3)I(6) and Mo(6)S(4.5)I(4.5) stoichiometries has also shown them to be soluble in common solvents like water, acetone or isopropyl alcohol, and to debundle on dilution. Here, the solubility, debundling and composition of Mo(6)S(2)I(8) nanowires are presented. They were found to be most soluble in dimethylformamide, which retained 47 wt% of a 0.08 gl(-1) nanowire (NW) material dispersion as thin NW bundles after one week. Dispersions of 0.8 gl(-1) and 5 gl(-1) even retained 54 wt% and 66 wt%, respectively. However the NW material was completely insoluble in water, and the surface energy of Mo(6)S(2)I(8) NWs was deduced as 67 mJ m(-2), higher than for other Mo-S-I NWs. UV-vis-NIR spectroscopy showed nanowire peaks familiar from Mo(6)S(3)I(6) and Mo(6)S(4.5)I(4.5) spectra around 1.8 and 2.8 eV, as well as unforeseen ultraviolet peaks at 3.5 and 4.4 eV. These chemical differences suggest an alternate, more strongly bonded structure to that seen for Mo(6)S(3)I(6) and Mo(6)S(4.5)I(4.5) NWs. Films deposited from a range of concentrations were investigated using atomic force microscopy (AFM) to determine bundle diameter distributions. The average diameter and the spread in diameters were found to decrease somewhat with decreasing concentration. However extrapolation gave a finite bundle size at infinite dilution, and an extension of the existing debundling model is proposed to take this into account. To confirm the nominal stoichiometry of Mo(6)S(2)I(8), which does not follow the generic Mo(6)S(x)I(9-x) formula of previous stoichiometries, EDX was carried out. The composition of nanowire bundles was found to be Mo(6)S(2.3)I(8.6), supporting the nominal composition.

7.
Medicines (Basel) ; 5(2)2018 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-30720786

RESUMO

Background: Anxiety and depression are conferring an increasing burden on society. Although treatments exist for both conditions, side effects, and difficulties accessing treatment prevent many people from receiving adequate assistance. Nutritional approaches have demonstrated some success in treating anxiety and depression. We plan to investigate whether a micronutrient formula, Daily Essential Nutrients, improves symptoms of anxiety and depression compared to a placebo in a community recruited sample. Methods: This will be a randomized, double blind placebo controlled study (RCT). Two hundred adults will be assigned to either a placebo or micronutrient group (placebo or Daily Essential Nutrients (DEN)) in a 1:1 ratio. Baseline data will be collected for 2 weeks, followed by 10 weeks of placebo or micronutrient intervention. Psychometrics will be used to measure progress and participant safety will be monitored weekly. Results: The primary outcome measures will be total scores on three measures of symptom severity at 10 weeks. Linear mixed modelling will be used to measure between group differences and effect sizes will be calculated using pooled mean scores and standard deviations over the course of the trial. Conclusions: If effective, micronutrients could provide an alternative treatment, with fewer barriers and adverse events than currently available treatments.

8.
Arch Osteoporos ; 13(1): 34, 2018 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-29564555

RESUMO

Osteoporosis (OP) causes reduced bone strength and increases risk of fractures. Medical records from specialist clinics in Japan of postmenopausal women with OP and high risk of fracture were analysed. Majority of patients were treated for OP as recommended and were prescribed OP medications soon after high-risk OP diagnosis. PURPOSE: The incidence of osteoporosis (OP) in Japan is predicted to increase significantly in coming decades. Resultant osteoporotic fractures are a significant contributor of economic and social burden among elderly osteoporosis patients. This retrospective chart review was conducted as a response to the current evidence gap in the treatment patterns for OP patients with high risk of fracture in Japan. METHODS: This was a multi-centre retrospective chart review that analysed data extracted from the medical records of postmenopausal OP patients at high risk for fracture who received care at 11 specialist clinics and medical centers in Japan for at least 18 to 24 months. Main outcome was OP treatment patterns. RESULTS: The study included 709 eligible patients of whom 623 (87.9%) were prescribed OP medication during the study period. The most common reason for not taking OP medication was patient unwillingness to take medication. The most common OP medications prescribed initially were minodronic acid (20.1%), alendronate (19.9%), raloxifene (14.1%), weekly teriparatide acetate (12.4%) and eldecalcitol (11.4%). Majority of patients (62.1%) were still taking their initial medication at the end of the 18-24 month follow-up. CONCLUSIONS: A high percentage of patients (87.9%) in Japan received OP medications soon after their high-risk diagnosis, with bisphosphonates, selective estrogen receptor modulators and teriparatide being the predominant treatment options.


Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Osteoporose Pós-Menopausa/tratamento farmacológico , Fraturas por Osteoporose/prevenção & controle , Padrões de Prática Médica/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Alendronato/uso terapêutico , Difosfonatos/uso terapêutico , Substituição de Medicamentos , Uso de Medicamentos/estatística & dados numéricos , Feminino , Humanos , Incidência , Japão/epidemiologia , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/epidemiologia , Fraturas por Osteoporose/epidemiologia , Cloridrato de Raloxifeno/uso terapêutico , Estudos Retrospectivos , Teriparatida/uso terapêutico , Vitamina D/análogos & derivados , Vitamina D/uso terapêutico
9.
Arch Osteoporos ; 13(1): 58, 2018 05 08.
Artigo em Inglês | MEDLINE | ID: mdl-29744677

RESUMO

In this article it was mistakenly stated that Akimitsu Miyauchi is affiliated with both Miyauchi Medical Center, Osaka and Amgen Astellas BioPharma K.K., Tokyo. In fact he is affiliated only with Miyauchi Medical Center; he has no connection with Amgen Astellas.

10.
Sci Adv ; 4(6): eaar7495, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29951584

RESUMO

Vibrational modes affect fundamental physical properties such as the conduction of sound and heat and can be sensitive to nano- and atomic-scale structure. Probing the momentum transfer dependence of vibrational modes provides a wealth of information about a materials system; however, experimental work has been limited to essentially bulk and averaged surface approaches or to small wave vectors. We demonstrate a combined experimental and theoretical methodology for nanoscale mapping of optical and acoustic phonons across the first Brillouin zone, in the electron microscope, probing a volume ~1010 to 1020 times smaller than that of comparable bulk and surface techniques. In combination with more conventional electron microscopy techniques, the presented methodology should allow for direct correlation of nanoscale vibrational mode dispersions with atomic-scale structure and chemistry.

11.
Nanoscale ; 8(20): 10548-52, 2016 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-27147128

RESUMO

Detonation nanodiamond particles (DND) contain highly-stable nitrogen-vacancy (N-V) centers, making it important for quantum-optical and biotechnology applications. However, due to the small particle size, the N-V concentrations are believed to be intrinsically very low, spawning efforts to understand the formation of N-V centers and vacancies, and increase their concentration. Here we show that vacancies in DND can be detected and quantified using simulation-aided electron energy loss spectroscopy. Despite the small particle size, we find that vacancies exist at concentrations of about 1 at%. Based on this experimental finding, we use ab initio calculations to predict that about one fifth of vacancies in DND form N-V centers. The ability to directly detect and quantify vacancies in DND, and predict the corresponding N-V formation probability, has a significant impact to those emerging technologies where higher concentrations and better dispersion of N-V centres are critically required.

12.
Micron ; 69: 35-42, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25474748

RESUMO

Here we report a methodology combining TEM, STEM, Transmission-EBSD and EELS to analyse the structural and chemical properties of the metal-oxide interface of corroded Zr alloys in unprecedented detail. TEM, STEM and diffraction results revealed the complexity of the distribution of suboxide grains at the metal-oxide interface. EELS provided accurate quantitative analysis of the oxygen concentration across the interface, identifying the existence of local regions of stoichiometric ZrO and Zr3O2 with varying thickness. Transmission-EBSD confirmed that the suboxide grains can be indexed with the hexagonal ZrO structure predicted with ab initio by Nicholls et al. (2014). The t-EBSD analysis has also allowed for the mapping of a relatively large region of the metal-oxide interface, revealing the location and size distribution of the suboxide grains.

13.
Adv Eng Mater ; 17(2): 211-215, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25892957

RESUMO

Zirconium-based alloys are used in water-cooled nuclear reactors for both nuclear fuel cladding and structural components. Under this harsh environment, the main factor limiting the service life of zirconium cladding, and hence fuel burn-up efficiency, is water corrosion. This oxidation process has recently been linked to the presence of a sub-oxide phase with well-defined composition but unknown structure at the metal-oxide interface. In this paper, the combination of first-principles materials modeling and high-resolution electron microscopy is used to identify the structure of this sub-oxide phase, bringing us a step closer to developing strategies to mitigate aqueous oxidation in Zr alloys and prolong the operational lifetime of commercial fuel cladding alloys.

14.
ACS Nano ; 9(11): 11398-407, 2015 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-26446310

RESUMO

A combination of scanning transmission electron microscopy, electron energy loss spectroscopy, and ab initio calculations is used to describe the electronic structure modifications incurred by free-standing graphene through two types of single-atom doping. The N K and C K electron energy loss transitions show the presence of π* bonding states, which are highly localized around the N dopant. In contrast, the B K transition of a single B dopant atom shows an unusual broad asymmetric peak which is the result of delocalized π* states away from the B dopant. The asymmetry of the B K toward higher energies is attributed to highly localized σ* antibonding states. These experimental observations are then interpreted as direct fingerprints of the expected p- and n-type behavior of graphene doped in this fashion, through careful comparison with density functional theory calculations.

15.
Chem Commun (Camb) ; 50(82): 12360-2, 2014 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-25187313

RESUMO

In this work it has been established that 3D nanoflowers of WS2 synthesised by chemical vapour deposition are composed of few layer WS2 along the edges of the petals. An experimental study in order to understand the evolution of these nanostructures shows the nucleation and growth along with the compositional changes they undergo.

16.
Frontline Gastroenterol ; 5(3): 183-189, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28839768

RESUMO

BACKGROUND: Ulcerative colitis is a lifelong, chronic, relapsing-remitting disease. OBJECTIVE: To assess the relationship between ulcerative colitis disease status and patient quality of life, and to determine the impact of ulcerative colitis on healthcare costs and work productivity, in the UK. METHODS: Clinicians assessed 173 adult patients' current disease status at a single study visit using the partial Mayo (pMayo) instrument. Patients completed the Euro Quality of Life 5-dimension, 5-level (EQ-5D-5L) questionnaire, the Work Productivity and Activity Impairment (WPAI) questionnaire. Healthcare resource use was determined from questionnaires and from patients' medical charts. RESULTS: Patients in remission had a significantly higher EQ-5D-5L scores (mean (SD) 0.86 (0.15)) than patients with active disease (0.71 (0.20); p<0.001). Patients with mild disease had significantly higher mean (SD) EQ-5D-5L scores than patients with moderate/severe disease: 0.77 (0.11) and 0.66 (0.24), respectively (p<0.001). The mean percent productivity impairment was greater for patients with active disease than for patients in remission on all items of the WPAI questionnaire: 24.6% vs 1.8% for work time missed, 34.1% vs 12.9% for impairment while working, 40.8% vs 14.4% for overall work impairment and 42.7% vs 13.0% for activity impairment (p<0.001 for all comparisons). The mean (SD) total cost of healthcare for ulcerative colitis in the prior 3 months was £1211 (1588). CONCLUSIONS: When compared with patients in remission, patients with active ulcerative colitis have significantly worse quality of life and significantly more work impairment. The healthcare costs of ulcerative colitis are considerable.

17.
J Crohns Colitis ; 8(7): 598-606, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24345767

RESUMO

BACKGROUND & AIMS: The burden of ulcerative colitis (UC) in relation to disease severity is not well documented. This study quantitatively evaluated the relationship between disease activity and quality of life (QoL), as well as health care utilization, cost, and work-related impairment associated with UC in an Australian population. METHODS: A cross-sectional, noninterventional, observational study was performed in patients with a wide range of disease severity recruited during routine specialist consultations. Evaluations included the Assessment of Quality of Life-8-dimension (AQoL-8D), EuroQol 5-dimension, 5-level (EQ-5D-5L), the disease-specific Inflammatory Bowel Disease Questionnaire (IBDQ), and the Work Productivity and Activity Impairment (WPAI) instrument. The 3-item Partial Mayo Score was used to assess disease severity. Health care resource utilization was assessed by chart review and patient questionnaires. RESULTS: In 175 patients, mean (SD) AQoL-8D and EQ-5D-5L scores were greater for patients in remission (0.80 [0.19] and 0.81 [0.18], respectively) than for patients with active disease (0.70 [0.20] and 0.72 [0.19], respectively, both Ps<0.001). IBDQ correlated with both AQoL-8D (r=0.73; P<0.0001) and EQ-5D-5L (0.69; P<0.0001). Mean 3-month UC-related health care cost per patient was AUD $2914 (SD=$3447 [mean for patients in remission=$1970; mild disease=$3736; moderate/severe disease=$4162]). Patients in remission had the least work and activity impairment. CONCLUSIONS: More severe UC disease was associated with poorer QoL. Substantial health care utilization, costs, and work productivity impairments were found in this sample of patients with UC. Moreover, greater disease activity was associated with greater health care costs and impairment in work productivity and daily activities.


Assuntos
Colite Ulcerativa/economia , Custos de Cuidados de Saúde , Serviços de Saúde/estatística & dados numéricos , Qualidade de Vida , Índice de Gravidade de Doença , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Austrália , Colite Ulcerativa/terapia , Estudos Transversais , Custos de Medicamentos , Eficiência , Feminino , Serviços de Saúde/economia , Hospitalização/economia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Inquéritos e Questionários , Avaliação da Capacidade de Trabalho , Adulto Jovem
18.
Chem Commun (Camb) ; 49(93): 10956-8, 2013 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-24135864

RESUMO

NanoBuds exist in a variety of stable structures. Our studies show that engineering NanoBud geometries is indeed possible and we visualise the transformation of one Nanobud geometry to another using in situ aberration corrected imaging techniques. Such NanoBuds are precursors for generating nanotube junctions which could be used in composite and electronic applications.


Assuntos
Nanotubos de Carbono/química , Aerossóis/química , Elétrons , Fulerenos/química
19.
ACS Nano ; 7(8): 7145-50, 2013 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-23869545

RESUMO

Precise control of graphene properties is an essential step toward the realization of future graphene devices. Defects, such as individual nitrogen atoms, can strongly influence the electronic structure of graphene. Therefore, state-of-the-art characterization techniques, in conjunction with modern modeling tools, are necessary to identify these defects and fully understand the synthesized material. We have directly visualized individual substitutional nitrogen dopant atoms in graphene using scanning transmission electron microscopy and conducted complementary electron energy loss spectroscopy experiments and modeling which demonstrates the influence of the nitrogen atom on the carbon K-edge.

20.
ACS Nano ; 6(9): 7800-5, 2012 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-22880934

RESUMO

The "doping" of carbon nanotubes with heteroatoms is an established method of controlling their properties. However, variations in heteroatom concentration in multiwalled carbon nanotubes (MWCNTs) tend to produce nanotubes with different morphologies, and hence varying properties, within the same sample. Electron energy loss spectroscopy in conjunction with imaging using a scanning transmission electron microscope (STEM) is a powerful tool to precisely map the spatial variation and bonding state of heteroatoms, e.g., B, N, P, Si, or combinations of these, present in carbon nanotubes exhibiting different structures. TEM analysis revealed that B incorporation during MWCNT growth (B-MWCNTs) results in nanotube morphologies that can be divided into three different types. These include core-shell structures possessing a B-rich core of cones and a C outer layer, B-containing cone structures, and MWCNTs with an irregular inner channel. In situ studies were carried out using Nanofactory() holder experiments in order to investigate the properties of individual B-MWCNTs and to show that the three types of nanotubes undergo different current-induced breakdown. The inhomogeneity in composition, structure, and properties of B-MWCNTs could result from the variation in chemical composition and temperature within the furnace, and this work highlights the importance of developing synthesis techniques that can control the inclusion of heteroatoms into nanotubes.


Assuntos
Boro/química , Cristalização/métodos , Nanotubos/química , Nanotubos/ultraestrutura , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA