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1.
Glob Chang Biol ; 30(4): e17259, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38655624

RESUMO

Nature-based climate solutions (NCS) are championed as a primary tool to mitigate climate change, especially in forested regions capable of storing and sequestering vast amounts of carbon. New England is one of the most heavily forested regions in the United States (>75% forested by land area), and forest carbon is a significant component of climate mitigation policies. Large infrequent disturbances, such as hurricanes, are a major source of uncertainty and risk for policies relying on forest carbon for climate mitigation, especially as climate change is projected to alter the intensity and extent of hurricanes. To date, most research into disturbance impacts on forest carbon stocks has focused on fire. Here, we show that a single hurricane in the region can down between 121 and 250 MMTCO2e or 4.6%-9.4% of the total aboveground forest carbon, much greater than the carbon sequestered annually by New England's forests (16 MMTCO2e year-1). However, emissions from hurricanes are not instantaneous; it takes approximately 19 years for downed carbon to become a net emission and 100 years for 90% of the downed carbon to be emitted. Reconstructing hurricanes with the HURRECON and EXPOS models across a range of historical and projected wind speeds, we find that an 8% and 16% increase in hurricane wind speeds leads to a 10.7- and 24.8-fold increase in the extent of high-severity damaged areas (widespread tree mortality). Increased wind speed also leads to unprecedented geographical shifts in damage, both inland and northward, into heavily forested regions traditionally less affected by hurricanes. Given that a single hurricane can emit the equivalent of 10+ years of carbon sequestered by forests in New England, the status of these forests as a durable carbon sink is uncertain. Understanding the risks to forest carbon stocks from disturbances is necessary for decision-makers relying on forests as a NCS.


Assuntos
Mudança Climática , Tempestades Ciclônicas , Florestas , New England , Carbono/análise , Sequestro de Carbono , Modelos Teóricos
2.
J Environ Manage ; 230: 43-52, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30265915

RESUMO

The Western Gulf Coast provides important habitat for migratory and resident waterfowl. The mottled duck (Anas fulvigula) relies on this region for all of its life-cycle events. Its relatively small population, limited worldwide range, and generally declining population trajectory has earned it a "Red" status on the Audubon WatchList and is a species of concern among state and federal agencies. The Western Gulf Coast (WGC) mottled duck population decline is believed to be primarily caused by the historical conversion and degradation of coastal wetlands and native prairie, and recent declines in cultivated rice. There is general agreement among experts that negative impacts to nesting and brood-rearing habitat are the most important threats to the WGC mottled duck population and increasing recruitment is essential to the growth and sustainability of the population. Our goal was to use available knowledge of mottled duck nesting and brood-rearing requirements to develop a model to aid managers in targeting areas for conservation and management. We developed four spatially explicit models that: 1) identify and prioritize existing mottled duck nesting habitat for conservation (e.g., protection or maintenance); 2) identify and prioritize existing mottled duck brood-rearing habitat for conservation; 3) identify and prioritize areas for grassland establishment; and 4) identify and prioritize wetland basins for freshwater enhancement. Spatial models revealed that only 6 km2 and 9 km2 of nesting and brood-rearing habitat, respectively, were identified as highest priority (top 10%) for conservation in the WGC. Brood habitat was identified as potentially limiting recruitment in the Texas Mid Coast and the Laguna Madre subregions of our study area, whereas grassland habitat was potentially limiting recruitment in Chenier Plain and Mississippi River Coastal Wetlands subregions. Spatial models also revealed that there is a high density of areas of high priority for grassland establishment inland in Texas and Louisiana. Likewise, there is a high density of wetland basins of high priority for freshwater enhancement throughout coastal Louisiana and the upper Texas coast. We used two separate measures to assess the performance of our Mottled Duck Decision Support Tool (hereafter MODU-DST) and found that it adequately identified patch suitability, as defined by our model, with ≥79% accuracy. Using data from the Cooperative Breeding Mottled Duck Survey, we also found that breeding mottled ducks were using landscapes with optimal spatial arrangement of nesting and brood-rearing habitat, which is reflected by higher mean priority rankings of nesting and brood-rearing habitat in the landscape.


Assuntos
Ecossistema , Animais , Comportamento Animal , Cruzamento , Patos , Água Doce , Áreas Alagadas
3.
J Sport Rehabil ; 25(2): 126-32, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-25658597

RESUMO

CONTEXT: The Unexpected-Disturbance Program (UDP) promotes exercises in response to so-called involuntary short- to midlatency disturbances. OBJECTIVE: This study investigated the effectiveness of the UDP in the last 6 wk of rehabilitation. DESIGN: Pre-post study with 2-tailed paired t tests for limited a priori comparisons to examine differences. SETTING: National Sports Institute of Malaysia. PARTICIPANTS: 24 Malaysian national athletes. INTERVENTIONS: 7 sessions/wk of 90 min with 3 sessions allocated for 5 or 6 UDP exercises. MAIN OUTCOMES: Significant improvements for men and women were noted. Tests included 20-m sprint, 1-repetition-maximum single-leg press, standing long jump, single-leg sway, and a psychological questionnaire. RESULTS: For men and women, respectively, average strength improvements of 22% (d = 0.96) and 29% (d = 1.05), sprint time of 3% (d = 1.06) and 4% (d = 0.58), and distance jumped of 4% (d = 0.59) and 6% (d = 0.47) were noted. In addition, athletes reported improved perceived confidence in their abilities. All athletes improved in each functional test except for long jump in 2 of the athletes. Mediolateral sway decreased in 18 of the 22 athletes for the injured limb. CONCLUSION: The prevention training with UDP resulted in improved conditioning and seems to decrease mediolateral sway.


Assuntos
Lesões do Ligamento Cruzado Anterior/reabilitação , Reconstrução do Ligamento Cruzado Anterior/reabilitação , Traumatismos em Atletas/reabilitação , Terapia por Exercício/métodos , Adulto , Lesões do Ligamento Cruzado Anterior/cirurgia , Traumatismos em Atletas/cirurgia , Desempenho Atlético/fisiologia , Teste de Esforço , Feminino , Humanos , Masculino , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Corrida/fisiologia , Resultado do Tratamento , Adulto Jovem
4.
J Strength Cond Res ; 28(8): 2314-23, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24796986

RESUMO

Previous investigators have speculated that applying additional external load throughout the eccentric phase of the jumping movement could amplify the stretch-shortening cycle mechanism and modulate jumping performance and jump exercise intensity. The aims of this study, therefore, were to determine the effect of increased eccentric phase loading, as delivered using an elastic device, on drop jumps (DJs) performed from different drop heights. Of specific interest were changes in (a) the kinetics; eccentric and concentric impulse, rate of force development (RFD), concentric velocity and (b) the electromyographic (EMG) activity of leg muscles. In a randomized repeated-measure study, 15 highly resistance trained male subjects performed DJs from 3 heights (20, 35, and 50 cm) under 3 different conditions: body weight only (free DJ) and with elastic bands providing downward force equivalent to 20% (+20% DJ) and 30% (+30% DJ) of body mass. All DJs were recorded using video and force plate data that were synchronized with EMG data. Results demonstrated that using additional tensile load during the airborne and eccentric phases of the DJ could enhance eccentric impulse (p = 0.042) and RFD (p < 0.001) and resulted in small to moderate effect size (ES) increases in quadriceps intergrated EMG across the eccentric phase (0.23 > ES > 0.51). The observed greater eccentric loading, however, did not immediately alter concentric kinetics and jump height nor did it alter muscle activation levels during this phase. The findings indicated that, in addition to the conventional technique of increasing drop height, using a tensile load during the airborne and eccentric phases of the DJ could further improve eccentric loading of DJs. As it has been suggested that eccentric impulse and RFD are indicators of DJ exercise intensity, these findings suggest that the loaded DJs, using additional elastic load, may be an effective technique for improving DJ exercise intensity without acute effects on the jumping performance and neuromuscular activation level in highly trained athletes.


Assuntos
Movimento/fisiologia , Contração Muscular/fisiologia , Condicionamento Físico Humano/métodos , Exercício Pliométrico , Músculo Quadríceps/fisiologia , Adulto , Desempenho Atlético/fisiologia , Fenômenos Biomecânicos , Eletromiografia , Humanos , Masculino , Condicionamento Físico Humano/fisiologia , Adulto Jovem
5.
Molecules ; 19(6): 8571-88, 2014 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-24959683

RESUMO

Matrix metalloproteinases (MMP) 2 and 9, the gelatinases, have consistently been associated with tumor progression. The development of gelatinase-specific probes will be critical for identifying in vivo gelatinoic activity to understand the molecular role of the gelatinases in tumor development. Recently, a self-assembling homotrimeric triple-helical peptide (THP), incorporating a sequence from type V collagen, with high substrate specificity to the gelatinases has been developed. To determine whether this THP would be suitable for imaging protease activity, 5-carboxyfluorescein (5FAM) was conjugated, resulting in 5FAM3-THP and 5FAM6-THP, which were quenched up to 50%. 5FAM6-THP hydrolysis by MMP-2 and MMP-9 displayed kcat/KM values of 1.5 × 104 and 5.4 × 103 M-1 s-1, respectively. Additionally 5FAM6-THP visualized gelatinase activity in gelatinase positive HT-1080 cells, but not in gelatinase negative MCF-7 cells. Furthermore, the fluorescence in the HT-1080 cells was greatly attenuated by the addition of a MMP-2 and MMP-9 inhibitor, SB-3CT, indicating that the observed fluorescence release was mediated by gelatinase proteolysis and not non-specific proteolysis of the THPs. These results demonstrate that THPs fully substituted with fluorophores maintain their substrate specificity to the gelatinases in human cancer cells and may be useful in in vivo molecular imaging of gelatinase activity.


Assuntos
Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Peptídeos/farmacocinética , Tomografia Óptica/métodos , Linhagem Celular Tumoral , Colágeno Tipo V/química , Fluoresceínas/química , Fluorescência , Corantes Fluorescentes/química , Humanos , Células MCF-7 , Microscopia Confocal , Microscopia de Fluorescência , Peptídeos/síntese química , Peptídeos/química
6.
J Appl Biomech ; 29(5): 628-33, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23182916

RESUMO

The amount of energy dissipated away from or returned to a child falling onto a surface will influence fracture risk but is not considered in current standards for playground impact-attenuating surfaces. A two-mass rheological computer simulation was used to model energy flow within the wrist and surface during hand impact with playground surfaces, and the potential of this approach to provide insights into such impacts and predict injury risk examined. Acceleration data collected on-site from typical playground surfaces and previously obtained data from children performing an exercise involving freefalling with a fully extended arm provided input. The model identified differences in energy flow properties between playground surfaces and two potentially harmful surface characteristics: more energy was absorbed by (work done on) the wrist during both impact and rebound on rubber surfaces than on bark, and rubber surfaces started to rebound (return energy to the wrist) while the upper limb was still moving downward. Energy flow analysis thus provides information on playground surface characteristics and the impact process, and has the potential to identify fracture risks, inform the development of safer impact-attenuating surfaces, and contribute to development of new energy-based arm fracture injury criteria and tests for use in conjunction with current methods.


Assuntos
Aceleração , Transferência de Energia/fisiologia , Pisos e Cobertura de Pisos , Mãos/fisiologia , Modelos Biológicos , Jogos e Brinquedos , Punho/fisiologia , Acidentes por Quedas , Criança , Simulação por Computador , Feminino , Humanos , Masculino , Estresse Mecânico , Propriedades de Superfície
7.
J Biochem Mol Toxicol ; 26(12): 506-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23169765

RESUMO

The carbamate pyridostigmine bromide has been used as a pretreatment to protect individuals from the nerve agent soman. Previous research showed that pyridostigmine significantly protected human muscle acetylcholinesterase in vitro from soman and bovine red blood cell acetylcholinesterase from some organophosphorous pesticides. Research presented here demonstrates that pretreatment with other carbamates also protects acetylcholinesterase from inhibition by the pesticides chlorpyrifos-oxon and diazinon-oxon, but not from malaoxon.


Assuntos
Carbamatos/farmacologia , Inibidores da Colinesterase/toxicidade , Organofosfatos/toxicidade , Praguicidas/toxicidade , Animais , Bovinos , Clorpirifos/análogos & derivados , Clorpirifos/toxicidade , Compostos Organofosforados/toxicidade
8.
J Biochem Mol Toxicol ; 26(1): 31-4, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21972196

RESUMO

Pyridostigmine bromide (PB) has been used to protect soldiers from the toxic effects of soman, a chemical warfare agent. Recent research shows that pyridostigmine bromide protects a significant percentage of acetylcholinesterase in isolated human intercostal muscle. Findings presented here indicate that red blood cell acetylcholinesterase is similarly protected by pyridostigmine bromide from the action of diisopropyl fluorophosphate and several organophosphate pesticides including chlorpyrifos-oxon, diazinon-oxon, and paraoxon, but not malaoxon, using the bovine red blood cell as a subject. These findings suggest that pretreatment with PB may protect growers, farmworkers, first responders, and the public, in general, from the effects of selected pesticides.


Assuntos
Clorpirifos/análogos & derivados , Inibidores da Colinesterase/toxicidade , Malation/análogos & derivados , Compostos Organofosforados/toxicidade , Paraoxon/toxicidade , Praguicidas/toxicidade , Substâncias Protetoras/farmacologia , Brometo de Piridostigmina/farmacologia , Acetilcolinesterase/metabolismo , Animais , Bovinos , Clorpirifos/toxicidade , Eritrócitos/efeitos dos fármacos , Eritrócitos/enzimologia , Malation/toxicidade
9.
Muscle Nerve ; 43(4): 591-5, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21404290

RESUMO

INTRODUCTION: Pretreatment with pyridostigmine bromide (PB) of human intercostal muscle fibers exposed to the irreversible acetylcholinesterase (AChE) inhibitor soman was investigated. METHODS: Muscles were pretreated with 3 × 10(-6) M PB or saline for 20 minutes, then exposed to 10(-7) M soman for 10 minutes. RESULTS: AChE of muscles treated with soman alone was inhibited >95%. In contrast, PB pretreatment of soman-exposed bundles protected 20% of AChE activity. AChE of bundles exposed to PB alone recovered after 4 hours, but bundles exposed to both PB and soman did not. Soman-induced reduction of resting membrane potentials and increment of amplitudes and decay times of miniature endplate potentials (MEPPs) were partially corrected by PB pretreatment. CONCLUSIONS: In vitro pretreatment of human muscles with PB protected up to 20% of muscle AChE and ameliorated some deleterious effects on endplate physiology induced by soman.


Assuntos
Acetilcolinesterase , Inibidores da Colinesterase/farmacologia , Músculos Intercostais/efeitos dos fármacos , Músculos Intercostais/enzimologia , Brometo de Piridostigmina/farmacologia , Soman/toxicidade , Acetilcolinesterase/metabolismo , Relação Dose-Resposta a Droga , Humanos , Técnicas de Cultura de Órgãos , Substâncias Protetoras/farmacologia
10.
Asian Cardiovasc Thorac Ann ; 29(8): 729-734, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33829870

RESUMO

BACKGROUND: Rheumatic heart disease affects more than 33,000,000 individuals, mostly from low- and middle-income countries. The Cape Town Declaration on Access to Cardiac Surgery in the Developing World was published in August 2018, signaling the commitment of the global cardiac surgery and cardiology communities to improving care for rheumatic heart disease patients. METHODS: As the Cape Town Declaration formed the basis for which the Cardiac Surgery Intersociety Alliance was formed, the purpose of this article is to describe the history of the Cardiac Surgery Intersociety Alliance, its formation, ongoing activities, and future directions, including the announcement of selected pilot sites. RESULTS: The Cardiac Surgery Intersociety Alliance is an international alliance consisting of representatives from major cardiothoracic surgical societies and the World Heart Federation. Activities have included meetings at annual conferences, exhibit hall participation for advertisement and recruitment, and publication of selection criteria for cardiac surgery centers to apply for Cardiac Surgery Intersociety Alliance support. Criteria focused on local operating capacity, local championing, governmental and facility support, appropriate identification of a specific gap in care and desire to engage in future research. Eleven applications were received for which three finalist sites were selected and site visits conducted. The two selected sites were Hospital Central Maputo (Mozambique) and King Faisal Hospital Kigali (Rwanda). CONCLUSIONS: Substantial progress has been made since the passing of the Cape Town Declaration and the formation of the Cardiac Surgery Intersociety Alliance, but ongoing efforts with collaboration of all committed parties-cardiac surgery, cardiology, industry, and government-will be necessary to improve access to life-saving cardiac surgery for rheumatic heart disease patients.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Cardiopatia Reumática , Cirurgia Torácica , Humanos , Cardiopatia Reumática/diagnóstico , Cardiopatia Reumática/cirurgia , Ruanda , África do Sul
11.
Ann Thorac Surg ; 111(6): 1931-1936, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33840453

RESUMO

BACKGROUND: Rheumatic heart disease (RHD) affects more than 33,000,000 individuals, mostly from low- and middle-income countries. The Cape Town Declaration On Access to Cardiac Surgery in the Developing World was published in August 2018, signaling the commitment of the global cardiac surgery and cardiology communities to improving care for RHD patients. METHODS: As the Cape Town Declaration formed the basis for which the Cardiac Surgery Intersociety Alliance (CSIA) was formed, the purpose of this article is to describe the history of the CSIA, its formation, ongoing activities, and future directions, including the announcement of selected pilot sites. RESULTS: The CSIA is an international alliance consisting of representatives from major cardiothoracic surgical societies and the World Heart Federation. Activities have included meetings at annual conferences, exhibit hall participation for advertisement and recruitment, and publication of selection criteria for cardiac surgery centers to apply for CSIA support. Criteria focused on local operating capacity, local championing, governmental and facility support, appropriate identification of a specific gap in care, and desire to engage in future research. Eleven applications were received for which three finalist sites were selected and site visits conducted. The two selected sites were Hospital Central Maputo (Mozambique) and King Faisal Hospital Kigali (Rwanda). CONCLUSIONS: Substantial progress has been made since the passing of the Cape Town Declaration and the formation of the CSIA, but ongoing efforts with collaboration of all committed parties-cardiac surgery, cardiology, industry, and government-will be necessary to improve access to life-saving cardiac surgery for RHD patients.


Assuntos
Cardiologia , Países em Desenvolvimento , Acessibilidade aos Serviços de Saúde , Cooperação Internacional , Cardiopatia Reumática/cirurgia , Sociedades Médicas/organização & administração , Procedimentos Cirúrgicos Cardíacos , Humanos , Cardiopatia Reumática/epidemiologia , África do Sul
12.
J Thorac Cardiovasc Surg ; 161(6): 2108-2113, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33840466

RESUMO

BACKGROUND: Rheumatic heart disease (RHD) affects more than 33,000,000 individuals, mostly from low- and middle-income countries. The Cape Town Declaration On Access to Cardiac Surgery in the Developing World was published in August 2018, signaling the commitment of the global cardiac surgery and cardiology communities to improving care for RHD patients. METHODS: As the Cape Town Declaration formed the basis for which the Cardiac Surgery Intersociety Alliance (CSIA) was formed, the purpose of this article is to describe the history of the CSIA, its formation, ongoing activities, and future directions, including the announcement of selected pilot sites. RESULTS: The CSIA is an international alliance consisting of representatives from major cardiothoracic surgical societies and the World Heart Federation. Activities have included meetings at annual conferences, exhibit hall participation for advertisement and recruitment, and publication of selection criteria for cardiac surgery centers to apply for CSIA support. Criteria focused on local operating capacity, local championing, governmental and facility support, appropriate identification of a specific gap in care, and desire to engage in future research. Eleven applications were received for which three finalist sites were selected and site visits conducted. The two selected sites were Hospital Central Maputo (Mozambique) and King Faisal Hospital Kigali (Rwanda). CONCLUSIONS: Substantial progress has been made since the passing of the Cape Town Declaration and the formation of the CSIA, but ongoing efforts with collaboration of all committed parties-cardiac surgery, cardiology, industry, and government-will be necessary to improve access to life-saving cardiac surgery for RHD patients.


Assuntos
Fortalecimento Institucional/organização & administração , Cardiopatia Reumática/cirurgia , Cirurgia Torácica/organização & administração , Humanos , Moçambique , Ruanda
13.
Eur J Cardiothorac Surg ; 59(6): 1139-1143, 2021 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-33830224

RESUMO

OBJECTIVES: Rheumatic heart disease (RHD) affects >33 000 000 individuals, mostly from low- and middle-income countries. The Cape Town Declaration on Access to Cardiac Surgery in the Developing World was published in August 2018, signalling the commitment of the global cardiac surgery and cardiology communities to improving care for patients with RHD. METHODS: As the Cape Town Declaration formed the basis for which the Cardiac Surgery Intersociety Alliance (CSIA) was formed, the purpose of this article is to describe the history of the CSIA, its formation, ongoing activities and future directions, including the announcement of selected pilot sites. RESULTS: The CSIA is an international alliance consisting of representatives from major cardiothoracic surgical societies and the World Heart Federation. Activities have included meetings at annual conferences, exhibit hall participation for advertisement and recruitment and publication of selection criteria for cardiac surgery centres to apply for CSIA support. Criteria focused on local operating capacity, local championing, governmental and facility support, appropriate identification of a specific gap in care and desire to engage in future research. Eleven applications were received for which 3 finalist sites were selected and site visits conducted. The 2 selected sites were Hospital Central Maputo (Mozambique) and King Faisal Hospital Kigali (Rwanda). CONCLUSIONS: Substantial progress has been made since the passing of the Cape Town Declaration and the formation of the CSIA, but ongoing efforts with collaboration of all committed parties-cardiac surgery, cardiology, industry and government-will be necessary to improve access to life-saving cardiac surgery for patients with RHD.


Assuntos
Procedimentos Cirúrgicos Cardíacos , Cardiopatia Reumática , Acessibilidade aos Serviços de Saúde , Humanos , Ruanda , África do Sul
14.
Environ Toxicol Chem ; 29(5): 1138-45, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20821550

RESUMO

Hydrocarbon-inducible cytochrome P4501A (CYP1A) expression was measured, as ethoxyresorufin-O-deethylase (EROD) activity, in livers of wintering harlequin ducks (Histrionicus histrionicus) captured in areas of Prince William Sound, Alaska, USA, oiled by the 1989 Exxon Valdez spill and in birds from nearby unoiled areas, during 2005 to 2009 (up to 20 years following the spill). The present work repeated studies conducted in 1998 that demonstrated that in harlequin ducks using areas that received Exxon Valdez oil, EROD activity was elevated nearly a decade after the spill. The present findings strongly supported the conclusion that average levels of hepatic EROD activity were higher in ducks from oiled areas than those from unoiled areas during 2005 to 2009. This result was consistent across four sampling periods; furthermore, results generated from two independent laboratories using paired liver samples from one of the sampling periods were similar. The EROD activity did not vary in relation to age, sex, or body mass of individuals, nor did it vary strongly by season in birds collected early and late in the winter of 2006 to 2007, indicating that these factors did not confound inferences about observed differences between oiled and unoiled areas. We interpret these results to indicate that harlequin ducks continued to be exposed to residual Exxon Valdez oil up to 20 years after the original spill. This adds to a growing body of literature suggesting that oil spills have the potential to affect wildlife for much longer time frames than previously assumed.


Assuntos
Biomarcadores , Citocromo P-450 CYP1A1/metabolismo , Patos , Petróleo/toxicidade , Poluentes Químicos da Água/toxicidade , Alaska , Animais , Exposição Ambiental , Indução Enzimática , Estações do Ano , Fatores de Tempo
15.
Drug Chem Toxicol ; 32(3): 182-5, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19538013

RESUMO

The normal range of human erythrocyte acetylcholinesterase (RBC-AChE) activity is important when monitoring exposure to pesticides and chemical warfare agents. A modification of Michel's method measured RBC-AChE activities from 991 individuals (818 males and 173 females) presumably unexposed to nerve agents. Median age was 42 (range, 18-76) years. RBC-AChE (mean +/- SD) was 0.74 +/- 0.06 delta pH units/hour. Multivariate linear regression showed an association with age (slope +0.0008 delta pH units/hour for each year; P < 0.001) unlikely to be clinically significant. The findings represent the largest study of human RBC-AChE to date providing measures of central tendency and variation.


Assuntos
Acetilcolinesterase/sangue , Eritrócitos/enzimologia , Adolescente , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Valores de Referência , Adulto Jovem
16.
Mil Med ; 174(11): 1196-202, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19960829

RESUMO

The biomechanical mechanisms of lower-limb injuries in the New Zealand Defense Force were identified from the circumstances of the injuries, and injury prevention strategies that addressed these mechanisms examined for their applicability to a military setting. Many of the injuries were the result of rolling or twisting movements and ankle instability was a common causal factor. Ankle bracing and stability training were identified as the strategies that address this factor and are most likely to be effective in preventing the injuries. A successful intervention strategy must also take into account the particular requirements of the user group. Concerns with ankle bracing included ongoing costs, individual fitting requirements, and the inability to remain effective under extremes of physical activity and external conditions. Stability training was considered more appropriate than ankle bracing for the defense force. Stability training is low cost and has the ability to address the biomechanical mechanisms of several lower-limb injuries. However, it requires trialing in a military setting to assess the logistics of implementation and whether the reported sport-specific programs should be adjusted for the varied physical activities undertaken by military forces.


Assuntos
Traumatismos da Perna/prevenção & controle , Militares , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Traumatismos da Perna/epidemiologia , Masculino , Nova Zelândia/epidemiologia , Fatores de Risco
17.
Bull Environ Contam Toxicol ; 83(1): 59-61, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19387522

RESUMO

Court-ordered monitoring of blood cholinesterases (ChEs) from orchard workers in Washington State is underway. In 2008, the mean red blood cell acetylcholinesterase (AChE, EC 3.1.1.7) activity was 9.65 +/- 1.11 micromoles/min/ml (n = 1,793) and the mean serum (BChE, 3.1.1.6) activity was 5.19 +/- 0.90 micromoles/min/ml (n = 1,811). Determinations were made using the Ellman assay and automated equipment of Pathology Associates Medical Laboratories (PAML), Spokane, Washington.


Assuntos
Agricultura , Colinesterases/sangue , Exposição Ocupacional , Acetilcolinesterase/sangue , Eritrócitos/enzimologia , Humanos , Washington
18.
Med Sci Sports Exerc ; 40(6): 1149-54, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18460989

RESUMO

PURPOSE: To investigate the effect of fastskin suits on 25- to 800-m performances, drag, and energy cost of swimming. METHODS: The performances, stroke rate and distance per stroke, were measured for 14 competitive swimmers in a 25-m pool, when wearing a normal suit (N) and when wearing a full-body suit (FB) or a waist-to-ankle suit (L). Passive drag, oxygen uptake, blood lactate, and the perceived exertion were measured in a flume. RESULTS: There was a 3.2% +/- 2.4% performance benefit for all subjects over the six distances covered at maximal speed wearing FB and L when compared with N. When wearing L, the gain was significantly lower (1.8% +/- 2.5%, P < 0.01) than when wearing FB compared with N. The exercise perception was significantly lower when wearing FB than N, whereas there was no statistical difference when wearing L. The distance per stroke was significantly higher when wearing FB and L, whereas the differences in stroke rate were not statistically significant. There was a significant reduction in drag when wearing FB and L of 6.2% +/- 7.9% and 4.7% +/- 4.4%, respectively (P < 0.01), whereas the energy cost of swimming was significantly reduced when wearing FB and L by 4.5% +/- 5.4% and 5.5% +/- 3.1%, respectively (P < 0.01). However, the differences between FB and L were not statistically significant for drag and oxygen uptake. CONCLUSION: FB and L significantly reduced passive drag, and this was associated with a decreased energy cost of submaximal swimming and an increased distance per stroke, at the same stroke rates, and reduced freestyle performance time.


Assuntos
Desempenho Atlético/fisiologia , Metabolismo Energético/fisiologia , Equipamentos Esportivos , Natação/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
19.
J Biomech ; 41(5): 1131-6, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18243218

RESUMO

The aim of this study was to develop a method to predict fluid forces acting on the human hand in unsteady flow swimming conditions. A mechanical system consisting of a pulley and chain mechanism and load cell was constructed to rotate a hand model in fluid flows. To measure the angular displacement of the hand model a potentiometer was attached to the axis of the rotation. The hand model was then fixed at various angles about the longitudinal axis of the hand model and rotated at different flow velocities in a swimming flume for 258 different trials to approximate a swimmer's stroke in unsteady flow conditions. Pressures were taken from 12 transducers embedded in the hand model at a sampling frequency of 200Hz. The resultant fluid force acting on the hand model was then determined on the basis of the kinetic and kinematic data taken from the mechanical system at the frequency of 200Hz. A stepwise regression analysis was applied to acquire higher order polynomial equations that predict the fluid force acting on the accelerating hand model from the 12 pressure values. The root mean square (RMS) difference between the resultant fluid force measured and that predicted from the single best-fit polynomial equation across all trials was 5N. The method developed in the present study accurately predicted the fluid forces acting on the hand model.


Assuntos
Mãos/fisiologia , Natação , Aceleração , Humanos , Modelos Biológicos , Pressão , Análise de Regressão , Reologia/instrumentação
20.
J Biomech ; 41(16): 3502-5, 2008 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-19019377

RESUMO

The purpose of this study was to quantify the effect of wave drag due to surface penetration on drag and lift forces (C(d) and C(l)) acting on a hand model. The values of C(d) and C(l) had been acquired to gain the hydrodynamic characteristics of the swimmer's hand and predict force on the swimmer's hand. These values have also been used to benchmark computational fluid dynamics analysis. Because the previous studies used a hand/forearm model which penetrated the water's surface, the values of C(d) and C(l) include the effect of the surface wave on the model. Wave formation causes pressure differences between the frontal and rear sides of a surface-penetrating model as a result of depressions and elevations in the water's surface. This may be considered as wave drag due to surface penetration. Fluid forces due to wave drag on the forearm should not be included in the measured C(d) and C(l) of a swimmer's hand that does not sweep near the water's surface. Two hand/forearm models are compared, one with the hand rigidly connected to the forearm. The other model was constructed to isolate the fluid forces acting on the hand from the influence of wave drag on the forearm. The measurements showed that the effect of wave drag on the hand model caused large increases in the values of C(d), up to 46-98% with lesser increases in C(l) of 2-12% depending on the hand orientation. The present study provides an improved method to determine the values of C(d) and C(l) that eliminates the effect of wave drag on a hand/forearm model by isolating the measurement of fluid forces on the forearm of the hand/forearm model in order to separately acquire the forces on the hand.


Assuntos
Mãos/anatomia & histologia , Mãos/fisiologia , Modelos Biológicos , Reologia/métodos , Natação/fisiologia , Simulação por Computador , Humanos , Estresse Mecânico
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