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1.
J Environ Manage ; 278(Pt 2): 111545, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33202370

RESUMO

Marine spatial planning (MSP) has rapidly become the most widely used integrated, place-based management approach in the marine environment. Monitoring and evaluation of MSP is key to inform best practices, adaptive management and plan iteration. While standardised evaluation frameworks cannot be readily applied, accounting for evaluation essentials such as the definition of evaluation objectives, indicators and stakeholder engagement of stakeholders is a prerequisite for meaningful evaluation outcomes. By way of a literature review and eleven practical MSP case studies, we analysed present day trends in evaluation approaches and unravelled the adoption of evaluation essentials for three categories for monitoring and evaluation for plan making, plan outcomes, and policy implementation. We found that at a global scale the focus of MSP evaluation has shifted over the past decade from evaluating predominantly plan outcomes towards the evaluation of plan making. Independent of the scope of the evaluation, evaluation approaches varied greatly from formal and structured processes, building for instance on MSP goals and objectives, to informal processes based on stakeholder interviews. We noted a trend in the adoption of formalised approaches where MSP evaluations have increasingly become linked to MSP policy goals and objectives. However, the enhanced use of MSP objectives and indicators did not result in a more straightforward reporting of outcomes, e.g. such as the achievement of specific MSP objectives. Overall, we found weak linkages between defined MSP objectives, indicators and available monitoring data. While the apparent shift towards a focus on objectives is promising, we highlight the need of fit-for-purpose monitoring data to enable effective evaluation of those objectives. Hence, effective MSP and adaptive management processes require customised and concurrent monitoring and evaluation strategies and procedures. We argue that evaluation processes would also benefit from a better understanding of the general environmental, socio-economic and socio-cultural effects of MSP. Therefore, to understand better environmental effects of MSP, we praise that forthcoming MSP processes need to deepen the understanding and considerations of cause-effect pathways between human activities and changes of ecosystem state through the adoption of targeted cumulative effects assessments.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Atividades Humanas , Humanos
2.
Clin Endocrinol (Oxf) ; 88(6): 920-927, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29446481

RESUMO

OBJECTIVE: Ovarian hyperstimulation syndrome (OHSS) is a serious iatrogenic condition, predominantly related to the hormone used to induce oocyte maturation during IVF treatment. Kisspeptin is a hypothalamic neuropeptide that has recently been demonstrated to safely trigger final oocyte maturation during IVF treatment even in women at high risk of OHSS. However, to date, the safety of kisspeptin has not been compared to current hormonal triggers of oocyte maturation. DESIGN: We conducted a retrospective single-centre cohort study investigating symptoms and clinical parameters of early OHSS in women at high risk of OHSS (antral follicle count or total number of follicles on day of trigger ≥23) triggered with human chorionic gonadotrophin (hCG) (n = 40), GnRH agonist (GnRHa; n = 99) or kisspeptin (n = 122) at Hammersmith Hospital IVF unit, London, UK (2013-2016). RESULTS: Clinical Parameters of OHSS: Median ovarian volume was larger following hCG (138 ml) than GnRHa (73 ml; P < .0001), and in turn kisspeptin (44 ml; P < .0001). Median ovarian volume remained enlarged 20-fold following hCG, 8-fold following GnRHa and 5-fold following kisspeptin compared to prestimulation ovarian volumes. Mean (±SD) ascitic volumes were lesser following GnRHa (9 ± 44 ml) and kisspeptin (5 ± 8 ml) than hCG (62 ± 84 ml; P < .0001). Symptoms of OHSS were most frequent following hCG and least frequent following kisspeptin. Diagnosis of OHSS: The odds ratio for OHSS diagnosis was 33.6 (CI 12.6-89.5) following hCG and 3.6 (CI 1.8-7.1) following GnRHa, when compared to kisspeptin. CONCLUSION: Triggering oocyte maturation by inducing endogenous gonadotrophin release is preferable to the use of exogenous hCG in women at high risk of OHSS.


Assuntos
Fertilização in vitro/efeitos adversos , Oócitos/citologia , Síndrome de Hiperestimulação Ovariana/patologia , Adulto , Gonadotropina Coriônica/farmacologia , Estudos de Coortes , Feminino , Humanos , Kisspeptinas/farmacologia , Síndrome de Hiperestimulação Ovariana/etiologia , Indução da Ovulação/efeitos adversos , Estudos Retrospectivos , Adulto Jovem
3.
J Mater Sci Mater Med ; 29(3): 30, 2018 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-29523976

RESUMO

The original version of this article unfortunately contained a mistake. E. Themistou was missing from the author group and so is now included with this erratum.

4.
J Mater Sci Mater Med ; 29(1): 14, 2017 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-29285611

RESUMO

Process-induced degradation of clinically relevant resorbable polymers was investigated for two thermal techniques, filament extrusion followed by fused deposition modelling (FDM). The aim was to develop a clear understanding of the relationship between temperature, processing time and resultant process-induced degradation. This acts to address the current knowledge gap in studies involving thermal processing of resorbable polymers. Poly(DL-lactide-co-glycolide) (PDLGA) was chosen for its clinically relevant resorption properties. Furthermore, a comparative study of controlled thermal exposure was conducted through compression moulding PDLGA at a selected range of temperatures (150-225 °C) and times (0.5-20 min). Differential scanning calorimetry (DSC) and gel permeation chromatography (GPC) were used to characterise thermally induced degradation behaviour. DSC proved insensitive to degradation effects, whereas GPC demonstrated distinct reductions in molecular weight allowing for the quantification of degradation. A near-exponential pattern of degradation was identified. Through the application of statistical chain scission equations, a predictive plot of theoretical degradation was created. Thermal degradation was found to have a significant effect on the molecular weight with a reduction of up to 96% experienced in the controlled processing study. The proposed empirical model may assist prediction of changes in molecular weight, however, accuracy limitations are highlighted for twin-screw extrusion, accredited to high-shear mixing. The results from this study highlight the process sensitivity of PDLGA and proposes a methodology for quantification and prediction, which contributes to efforts in understanding the influence of manufacture on performance of degradable medical implants.


Assuntos
Materiais Biocompatíveis/química , Ácido Láctico/química , Poliésteres/química , Poliglactina 910/química , Ácido Poliglicólico/química , Alicerces Teciduais , Implantes Absorvíveis , Osso e Ossos , Varredura Diferencial de Calorimetria , Cromatografia em Gel , Portadores de Fármacos , Temperatura Alta , Peso Molecular , Reprodutibilidade dos Testes
5.
J Mater Sci Mater Med ; 27(2): 22, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26704539

RESUMO

Bone tissue engineering may provide an alternative to autograft, however scaffold optimisation is required to maximize bone ingrowth. In designing scaffolds, pore architecture is important and there is evidence that cells prefer a degree of non-uniformity. The aim of this study was to compare scaffolds derived from a natural porous marine sponge (Spongia agaricina) with unique architecture to those derived from a synthetic polyurethane foam. Hydroxyapatite scaffolds of 1 cm(3) were prepared via ceramic infiltration of a marine sponge and a polyurethane (PU) foam. Human foetal osteoblasts (hFOB) were seeded at 1 × 10(5) cells/scaffold for up to 14 days. Cytotoxicity, cell number, morphology and differentiation were investigated. PU-derived scaffolds had 84-91% porosity and 99.99% pore interconnectivity. In comparison marine sponge-derived scaffolds had 56-61% porosity and 99.9% pore interconnectivity. hFOB studies showed that a greater number of cells were found on marine sponge-derived scaffolds at than on the PU scaffold but there was no significant difference in cell differentiation. X-ray diffraction and inductively coupled plasma mass spectrometry showed that Si ions were released from the marine-derived scaffold. In summary, three dimensional porous constructs have been manufactured that support cell attachment, proliferation and differentiation but significantly more cells were seen on marine-derived scaffolds. This could be due both to the chemistry and pore architecture of the scaffolds with an additional biological stimulus from presence of Si ions. Further in vivo tests in orthotopic models are required but this marine-derived scaffold shows promise for applications in bone tissue engineering.


Assuntos
Materiais Biomiméticos/química , Diferenciação Celular , Durapatita/química , Osteoblastos/fisiologia , Poríferos/química , Alicerces Teciduais/química , Animais , Materiais Biocompatíveis/química , Células Cultivadas , Cobaias , Humanos , Teste de Materiais , Osteoblastos/citologia , Osteogênese/fisiologia , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos
7.
Child Care Health Dev ; 40(4): 492-7, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23662595

RESUMO

BACKGROUND: We examined the feasibility of self-directed Triple P 'Positive Parenting Programme' for optimizing parents' management of childhood asthma and behaviour. METHODS: Eligible families were invited to access asthma-specific web-based Triple P as part of a preliminary randomized controlled study. RESULTS: Initial study information and introductory website pages received considerable interest but intervention uptake was poor with high rates of attrition. CONCLUSIONS: Although parents of children with asthma show willingness to access web-based parenting support, further work is necessary to develop engaging websites and determine barriers to uptake, and adherence to online parenting interventions with this population.


Assuntos
Asma/psicologia , Disseminação de Informação/métodos , Internet , Poder Familiar , Pais/educação , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Cooperação do Paciente/estatística & dados numéricos , Adulto , Asma/epidemiologia , Asma/terapia , Criança , Pré-Escolar , Medicina Baseada em Evidências , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Avaliação de Resultados em Cuidados de Saúde , Poder Familiar/psicologia , Pais/psicologia , Avaliação de Programas e Projetos de Saúde , Inquéritos e Questionários , Reino Unido/epidemiologia
8.
Scott Med J ; 57(2): 65-8, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22555224

RESUMO

The views of the parents of children undergoing elective surgery are not well represented in the literature. The aim of this study was to identify the priorities of parents with a view to improve their satisfaction. A questionnaire-based survey was conducted among parents of children undergoing elective surgery between November 2007 and March 2008. A total of 337 completed questionnaires were received. A similar survey was conducted among 12 surgeons, and their views were compared. Forty-three percent of parents preferred to know about a procedure on the day of surgery while others wanted the information in advance. Parents were most concerned with the complications of surgery and least concerned with the scar. Most of the surgeons thought it was not essential to mention their level of experience and the detailed surgical procedure to the parents while obtaining consent for surgery. In contrast, the parents thought that knowing the experience of the operating surgeon and the detailed surgical procedure was more important than knowing the duration of operation and the surgical incision. Face-to-face discussion with a surgeon was the most preferred mode of communication. Although 82% of parents have access to the Internet, booklets were more popular among parents than online information. Twelve percent of parents wanted the information in a foreign language. This survey reveals the perspective of parents about their child's surgery and identifies the differences in opinion between patients and surgeons about the information to be provided before surgery. Tailoring information to the parents' priorities will improve parent satisfaction.


Assuntos
Procedimentos Cirúrgicos Eletivos/psicologia , Pais/psicologia , Criança , Pré-Escolar , Comunicação , Tomada de Decisões , Feminino , Pesquisas sobre Atenção à Saúde , Humanos , Lactente , Pediatria , Relações Profissional-Família , Inquéritos e Questionários
9.
Child Care Health Dev ; 37(4): 571-80, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21143268

RESUMO

BACKGROUND: Haemopoietic stem cell transplantation (HSCT) is a life-saving but intensive procedure associated with potentially severe adverse late effects. We aimed to determine morbidity and health-related quality of life (HRQOL) in a sample of survivors aged 8-18 years at least 1 year post HSCT for paediatric acute leukaemia, compared with a non-transplanted group of survivors matched for age, gender, initial disease and time since treatment. METHODS: Families (N = 54; HSCT n= 29) recruited from four UK centres completed measures of child behaviour and school attendance, HRQOL and finances. Mothers completed measures of their own well-being. Clinical outcome data were extracted from medical records. RESULTS: Children in the HSCT group had significantly more late effects and had received more tests for vision, bone, dental and skin health, and thyroid, lung, and gonadal function than the non-transplanted group. HRQOL scores for the HSCT group were significantly lower in all domains compared with the non-transplanted group and population norms, but were not significantly related to clinical indices. Mothers in the HSCT group had significantly poorer mental well-being than population norms. CONCLUSION: Significant morbidity and compromised HRQOL was found in survivors of HSCT. The burden of caring for a child after HSCT has a continuing toll on mothers' well-being.The importance of counselling families about possible long-term consequences is emphasized.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Leucemia/cirurgia , Qualidade de Vida , Adolescente , Estudos de Casos e Controles , Criança , Feminino , Nível de Saúde , Humanos , Leucemia/epidemiologia , Masculino , Morbidade , Mães/psicologia , Fatores de Risco , Sobreviventes , Fatores de Tempo , Reino Unido/epidemiologia
10.
Br J Dermatol ; 163(3): 481-6, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20426784

RESUMO

BACKGROUND: Vitiligo is a visible condition that is more noticeable in darker-skinned people. Beliefs about illness have been linked to psychosocial adjustment. There is some evidence that such beliefs may be influenced by cultural factors. Surprisingly little is known about beliefs in relation to vitiligo. OBJECTIVES: The study sought to explore in depth the ways in which British Asian women manage and adjust psychosocially to vitiligo, and the potential role of ethnicity and culture in this process. METHODS: In-depth semistructured interviews were conducted with seven British women of South Asian decent and analysed using the qualitative method of template analysis. RESULTS: Participants described feeling visibly different and all had experienced stigmatization to some extent. Avoidance and concealment were commonplace. Experiences of stigmatization were often perceived to be associated with cultural values related to appearance, status, and myths linked to the cause of the condition. CONCLUSIONS: The findings of this study present a unique in-depth analysis of British South Asians living with vitiligo and suggest there is a need for further research to explore cultural associations of disfigurement and of adjustment to chronic skin conditions. Furthermore, they suggest that in addition to individual therapeutic interventions there may be a need for community interventions aimed at dispelling myths and raising awareness of sources of support and treatment.


Assuntos
Povo Asiático/etnologia , Estereotipagem , Vitiligo/psicologia , Adaptação Psicológica , Adulto , Povo Asiático/psicologia , Atitude Frente a Saúde/etnologia , Doença Crônica , Cultura , Feminino , Humanos , Pessoa de Meia-Idade , Pesquisa Qualitativa , Autoimagem , Apoio Social , Reino Unido , Vitiligo/etnologia , Adulto Jovem
11.
Child Care Health Dev ; 36(1): 118-22, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19961496

RESUMO

BACKGROUND: Thalassaemia Major (TM) is a serious condition characterized by life-long dependence on blood transfusions and chelation therapy. Our aim was to determine health-related quality of life (HRQOL) in children with TM living in the UK, and the impact of caring for a child receiving National Health Service treatment on family finances. METHODS: This was a cross-sectional assessment of HRQOL in children (n= 22) with TM aged 8-18 years. Children were recruited from three UK Paediatric Haematology and Bone Marrow Transplant centres. Mothers completed measures of their child's HRQOL [PedsQL 4.0 (Measurement Model for the Pediatric Quality of Life Inventory, James W. Varni PhD, PedMetrics, Quantifying the Qualitative SM, Copyright 1998-2009)] and behaviour (Strengths and Difficulties questionnaire), and the impact of caring for the child on family finances. RESULTS: Child behaviour was within the normal range but child HRQOL was significantly lower than population norms. Family financial concerns associated with TM were associated with poorer child HRQOL (P= 0.020). CONCLUSIONS: Thalassaemia Major poses a considerable challenge to child HRQOL, well documented in areas of the world where TM is prevalent. Despite the availability of National Health Service care and financial benefits our study suggests a similar burden in the UK.


Assuntos
Efeitos Psicossociais da Doença , Nível de Saúde , Qualidade de Vida , Talassemia beta/economia , Talassemia beta/psicologia , Adolescente , Adulto , Criança , Família , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Apoio Social , Inquéritos e Questionários , Reino Unido , Talassemia beta/terapia
12.
Bone Joint Res ; 8(6): 266-274, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31346455

RESUMO

OBJECTIVES: Bioresorbable orthopaedic devices with calcium phosphate (CaP) fillers are commercially available on the assumption that increased calcium (Ca) locally drives new bone formation, but the clinical benefits are unknown. Electron beam (EB) irradiation of polymer devices has been shown to enhance the release of Ca. The aims of this study were to: 1) establish the biological safety of EB surface-modified bioresorbable devices; 2) test the release kinetics of CaP from a polymer device; and 3) establish any subsequent beneficial effects on bone repair in vivo. METHODS: ActivaScrew Interference (Bioretec Ltd, Tampere, Finland) and poly(L-lactide-co-glycolide) (PLGA) orthopaedic screws containing 10 wt% ß-tricalcium phosphate (ß-TCP) underwent EB treatment. In vitro degradation over 36 weeks was investigated by recording mass loss, pH change, and Ca release. Implant performance was investigated in vivo over 36 weeks using a lapine femoral condyle model. Bone growth and osteoclast activity were assessed by histology and enzyme histochemistry. RESULTS: Calcium release doubled in the EB-treated group before returning to a level seen in untreated samples at 28 weeks. Extensive bone growth was observed around the perimeter of all implant types, along with limited osteoclastic activity. No statistically significant differences between comparative groups was identified. CONCLUSION: The higher than normal dose of EB used for surface modification did not adversely affect tissue response around implants in vivo. Surprisingly, incorporation of ß-TCP and the subsequent accelerated release of Ca had no significant effect on in vivo implant performance, calling into question the clinical evidence base for these commercially available devices.Cite this article: I. Palmer, S. A. Clarke, F. J Buchanan. Enhanced release of calcium phosphate additives from bioresorbable orthopaedic devices using irradiation technology is non-beneficial in a rabbit model: An animal study. Bone Joint Res 2019;8:266-274. DOI: 10.1302/2046-3758.86.BJR-2018-0224.R2.

13.
Bone Marrow Transplant ; 42(2): 73-82, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18500369

RESUMO

We review evidence concerning health-related quality of life (HRQL) following paediatric haemopoietic stem cell transplant. The aims are to determine (1) HRQL compared with population norms; (2) changes in HRQL over time and (3) relations between pre-transplant variables (disease, individual and family resources) and survivor HRQL. Five databases were searched for articles published between January 1990 and February 2008. A total of 15 studies including 12 separate cohorts were identified. (1) HRQL was comparable with or better than population norms 6 months to 8 years post transplant. (2) HRQL was already compromised pre-transplant, further impaired immediately following conditioning, but improved 4-12 months post transplant. (3) Pre-transplant predictors of HRQL include family functioning and individual resources (for example, social skills). Identification of pre-transplant variables associated with long-term HRQL is invaluable to inform early psychological intervention and facilitate positive adjustment.


Assuntos
Transplante de Células-Tronco Hematopoéticas/psicologia , Qualidade de Vida , Criança , Transplante de Células-Tronco Hematopoéticas/mortalidade , Humanos , Sobreviventes
14.
Bone ; 40(4): 939-47, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17175212

RESUMO

Currently, available synthetic bone substitutes have adequate osteoconductive properties but have little or no osteoinductivity. Recent research has focused on using osteogenic growth factors or cells to provide this. JAX is a beta tricalcium phosphate bone graft substitute that has a novel shape and interlocking design. This study investigated delivery methods and the use of autologous cell therapy to enhance healing of a bone defect using JAX as a scaffold. Bone marrow was harvested from 24 New Zealand White rabbits. The mononuclear cell fraction was isolated and culture expanded. Bilateral 1.5 cm defects in the ulna were filled with: Group 1: JAX alone, Group 2: JAX plus 1x10(7) autologous BMSCs injected at the time of surgery, Group 3: JAX plus 8x10(6) autologous BMSCs cultured on granules for 14 days prior to surgery, Group 4: JAX plus fresh bone marrow (BMA), Group 5: cortical autograft, Group 6: JAX plus 2.5 microg VEGF. Radiographs demonstrated that there was more new bone in the BMA and VEGF groups compared to JAX alone. Groups containing autologous BMSCs were only slightly better than JAX alone in the amount of bone in the defect but did improve bridging of the osteotomy. Histomorphometry identified a significant increase in bone volume in the BMA group compared to JAX alone. BMA and VEGF enhanced healing of bone defects whereas expanded BMSCs provided little advantage over scaffold alone. There was no difference between delivery methods of autologous BMSCs. These observations suggest that the provision of osteogenic cells alone is insufficient to enhance bone healing and that additional factors are required to initiate this process in vivo.


Assuntos
Substitutos Ósseos/uso terapêutico , Fosfatos de Cálcio/uso terapêutico , Fraturas da Ulna/terapia , Animais , Transplante de Medula Óssea , Consolidação da Fratura/efeitos dos fármacos , Masculino , Microscopia Eletrônica de Varredura , Osteogênese , Coelhos , Radiografia , Células Estromais/transplante , Transplante Autólogo , Fraturas da Ulna/diagnóstico por imagem , Fraturas da Ulna/patologia , Fator A de Crescimento do Endotélio Vascular/uso terapêutico
15.
Acta Biomater ; 3(4): 563-72, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17270508

RESUMO

There is currently a need to expand the range of graft materials available to orthopaedic surgeons. This study investigated the effect of ternary phosphate-based glass (PBG) compositions on the behaviour of osteoblast and osteoblast-like cells. PBGs of the formula (in mol.%) P(2)O(5)(50)-CaO(50-X)-Na(2)O(X), where X is either 2, 4, 6, 8 or 10, were produced and their influence on the proliferation, differentiation and death in vitro of adult human bone marrow stromal cells (hBMSCs) and human fetal osteoblast 1.19 (HFOB 1.19) cells were assessed. Tissue culture plastic (TCP) and hydroxyapatite (HA) were used as controls. Exposure to PBGs in culture inhibited cell adhesion and proliferation and increased cell death in both cell types studied. There was no significant difference in percentage cell death between the PBGs, which was significantly greater than the controls. However, compared with other PBGs, a greater number of cells were found on the 48mol.% CaO which may have been due to either increased adherence or proliferation, or both. This composition was capable of supporting osteogenic proliferation and early differentiation, and supports the notion that chemical modification of the glass could lead to a more biologically compatible substrate with the potential to support osteogenic grafting. Realisation of this potential should lead to the development of novel grafting strategies for the treatment of problematic bone defects.


Assuntos
Vidro/química , Osteoblastos/citologia , Osteoblastos/fisiologia , Fosfatos/química , Células Estromais/citologia , Células Estromais/fisiologia , Adulto , Células da Medula Óssea/citologia , Adesão Celular , Técnicas de Cultura de Células , Morte Celular , Diferenciação Celular , Sobrevivência Celular , Células Cultivadas , Durapatita/química , Feto , Humanos , Osteoblastos/metabolismo , Osteoblastos/ultraestrutura , Fosfatos/metabolismo , Plásticos/química , Células Estromais/metabolismo , Células Estromais/ultraestrutura
16.
Rev Sci Instrum ; 78(1): 013101, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17503901

RESUMO

Obtaining velocity information from the interaction of a laser pulse on a metal layer provides insight into the rapid dynamics of material removal and plasma plume physics during ablation. A traditional approach involves using a velocity interferometer system for any reflector (VISAR) on a reflective metal surface. However, when the target is a thin metal layer, the cohesion of the surface is quickly lost resulting in a large spread of particle velocities that cannot be easily resolved by VISAR. This is due to material ejection"confusing" the VISAR measurement surface, effectively washing out the spatial fringe visibility in the VISAR interferometer. A new heterodyne-based optical velocimeter method is the photonic Doppler velocimeter (PDV). Because PDV tracks motion in a frequency encoded temporal electro-optical signal, velocity information is preserved and allows for multiple velocity components to be recorded simultaneously. The challenge lies in extracting PDV velocity information at short (nanosecond) laser ablation time scales with rapidly varying heterodyne beats by using electronic, optical, and analytical techniques to recover the velocity information from a fleeting signal. Here we show how we have been able to obtain velocity information on the nanosecond time scale and are able to compare it to hydrodynamic simulations. Also, we examine refinements to our PDV system by increasing the bandwidth, utilizing different probes, and sampling different analysis techniques.


Assuntos
Efeito Doppler , Lasers , Metais/análise , Análise Espectral
17.
Cancer Res ; 35(4): 1099-102, 1975 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-1116144

RESUMO

Hexamethylmelamine is known to be effective in humans in the treatment of certain malignant tumors, especially bronchial carcinoma. It is, however, quite inactive against a number of animal tumors, making difficult a study of its mechanism of action in experimental systems. In a reexamination of the effects of hexamethylmelamine, two tumors were found to be very sensitive, namely, a mouse plasma cell tumor (PC6) and a human bronchial carcinoma (P246) growing in immune deprived mice. Both tumors undergo a significant and almost complete regression, even when well established, and hence may serve as model systems for the study of the mechanism of action of hexamethylmelamine.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias Pulmonares/tratamento farmacológico , Plasmocitoma/tratamento farmacológico , Triazinas/uso terapêutico , Animais , Neoplasias Brônquicas/tratamento farmacológico , Dimetilaminas/uso terapêutico , Humanos , Terapia de Imunossupressão , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos CBA , Modelos Biológicos , Transplante de Neoplasias , Neoplasias Experimentais/tratamento farmacológico , Transplante Heterólogo
18.
Science ; 289(5480): 727, 2000 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-17819565
19.
J Orthop Res ; 22(5): 1016-24, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15304274

RESUMO

Currently available synthetic bone substitutes perform poorly compared to autograft. It is hoped that by adding osteogenic growth factors to the materials, new bone formation could be increased and the clinical outcome improved. In this study, IGF-1, bFGF and TGFbeta1, alone and in combination, were absorbed onto a carrier of beta-tricalcium phosphate (betaTCP) and implanted into a defect around a hydroxyapatite-coated, stainless steel implant in the proximal tibia of rat in a model of revision arthroplasty. Animals were sacrificed at 6 and 26 weeks for routine histology and histomorphometry and mechanical push out tests. The results show that only bFGF had a significant effect on ceramic resorption. The groups that received bFGF and bFGF in combination with TGFbeta1 had smaller and fewer betaTCP particles remaining in the defect at 6 and 26 weeks. No growth factor combination significantly enhanced new bone formation or the mechanical strength of the implant. These results indicate that, of the growth factors tested, only bFGF had any beneficial effect on the host response to the implant, perhaps by delaying osteoblast differentiation and thereby prolonging osteoclast access to the ceramic.


Assuntos
Desenvolvimento Ósseo/efeitos dos fármacos , Fator 2 de Crescimento de Fibroblastos/farmacologia , Implantes Experimentais , Fator de Crescimento Insulin-Like I/farmacologia , Tíbia/cirurgia , Fator de Crescimento Transformador beta/farmacologia , Animais , Fosfatos de Cálcio/análise , Cerâmica , Masculino , Osteoblastos/fisiologia , Ratos , Ratos Sprague-Dawley , Fator de Crescimento Transformador beta1
20.
J Neurosurg ; 75(1): 108-14, 1991 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-2045893

RESUMO

The loss of somatosensory evoked potentials (SSEP's) was investigated in a feline model of intracranial hypertension. Threshold values of cerebral perfusion pressure (CPP) and cerebral blood flow (CBF) required for maintenance of SSEP's are defined using a mathematical model. The model describes loss of amplitude of SSEP's using the form of a dose-response curve. Amplitude of the SSEP's declined to 50% of control values at a CBF of 15 ml/100 gm/min and a CPP of 20 mm Hg in the normoxic animal; in the presence of mild hypoxia (8 to 9 kPa), a significant increase in these values to 18 ml/100 gm/min and 32 mm Hg, respectively, occurred. No reliable changes in latency or central conduction time were demonstrated. It is concluded that given adequate oxygenation, evoked electrical activity is lost at too low a level of CPP for this parameter to be useful in clinical monitoring. However, even mild hypoxia, when combined with intracranial hypertension, produces a major risk to neuronal integrity.


Assuntos
Potenciais Somatossensoriais Evocados/fisiologia , Hipóxia/complicações , Pseudotumor Cerebral/fisiopatologia , Animais , Gatos , Circulação Cerebrovascular , Feminino , Masculino , Modelos Biológicos , Monitorização Fisiológica , Pseudotumor Cerebral/complicações , Tempo de Reação/fisiologia
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