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2.
Nature ; 615(7951): S86, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36890389
4.
Int J Biometeorol ; 67(2): 219-231, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36402916

RESUMO

In commercial dairy cows, the conditions in which they are kept may lead to negative emotional states associated with the development of chronic physiological and behavioural abnormalities that may compromise their health, welfare and productivity. Such states include fear, stress or anxiety. Behavioural rather than physiological tests are more likely to be used to indicate these states but can be limited by their subjectivity, need for specialised infrastructure and training (of the operator and sometimes the animal) and the time-consuming nature of data collection. Popularly used physiological measures such as blood cortisol may be more appropriate for acute rather than chronic assessments but are easily confounded, for example by a response to the act of measurement per se. More sophisticated physiological measures such as functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) may be impractical due to cost and time and, like blood cortisol, have the confounding associated with the act of measurement. By contrast, infrared thermography of external body surfaces is remote, non-invasive, easily repeated and follows an objective methodology, allowing longitudinal data acquisition for the inference of changes in chronic emotional state over time. The objective of this review was to investigate the potential of infrared thermography to measure cow emotions. In lactating dairy cows, maximum IRT of the eyes and coronary band of the limbs seem to be most representative of thermoregulatory changes, which are repeatable and correlate with behavioural and physiological indicators of emotional state. IRT methodologies have the potential to become a fundamental tool for the objective assessment of welfare state in dairy cows.


Assuntos
Hidrocortisona , Termografia , Animais , Feminino , Bovinos , Termografia/métodos , Lactação , Emoções/fisiologia , Regulação da Temperatura Corporal
5.
J Dairy Sci ; 105(10): 8454-8469, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36055840

RESUMO

Panting score (PS) is a common research tool used to assess the physiological state of cows exposed to heat stress, but it is subjective. Infrared temperature (IRT), measured by either infrared thermometers or cameras, may be a more objective and reliable alternative. Very few studies thus far have evaluated the associations between PS, IRT, and milk production. We investigated the applicability of IRT compared with PS as a means of assessing heat stress and milk yield reduction in dairy cows in tropical smallholder dairy farms (SDF). In autumn 2017, SDF located across 4 typical dairy regions of Vietnam were each visited once to collect farm (n = 32) and individual cow data (n = 344). For each SDF, heat load index (HLI) inside the cowsheds, an indicator of environmental heat load calculated from ambient temperature, humidity, and wind speed, was measured. For each cow, PS (0 indicates a cow breathing normally, not panting; 4.5 indicates an extremely heat-stressed cow with excessive panting, tongue fully extended, and excessive drooling), IRT of the cow's body, single-day energy-corrected milk yield (ECM), body weight, and body condition score were measured. Cow genotype, age, lactation number, and days in milk were recorded. The IRT of the cows' inner vulval lip (IVuT) were measured with an infrared thermometer; and the IRT of the cows' vulval surface (OVuT), inner tail base surface (ITBT), ocular area, muzzle, armpit area, paralumbar fossa area, fore udder, rear udder, fore hoof, and hind hoof were also measured with an infrared camera. Multivariate mixed-effects models were used to assess the associations between HLI with PS and IRT, and associations between PS and IRT with ECM while accounting for the effects of other cow variables. All IRT correlated positively with PS (Pearson correlation, r = 0.23-0.50). Each unit increase in HLI was associated with increases of 0.07 units in PS and 0.09 to 0.23°C in IRT. Each degree (°C) increase in IVuT, OVuT, and ITBT was associated with decreases of 0.75, 0.87, and 0.70 kg/cow per day in ECM, respectively, whereas PS and other IRT were not significantly associated with ECM. Thus, all IRT showed potential to assess the heat stress level of cows; and IVuT, OVuT, and ITBT, but not PS and other IRT, showed potential to predict ECM reduction in cows during heat stress. First cross (F1) Holstein Brown Swiss and F1 Holstein Jersey showed lower PS and yielded higher ECM than the third backcross (B3) Holstein Zebu (7/8 Holstein + 1/8 Zebu) and pure Holstein. Thus, F1 Holstein Brown Swiss and F1 Holstein Jersey could be more suitable for tropical SDF than B3 Holstein Zebu and pure Holstein.


Assuntos
Doenças dos Bovinos , Transtornos de Estresse por Calor , Animais , Bovinos , Fazendas , Feminino , Transtornos de Estresse por Calor/veterinária , Resposta ao Choque Térmico , Temperatura Alta , Lactação/fisiologia , Leite , Tecnologia
6.
J Anim Breed Genet ; 139(2): 145-160, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34559415

RESUMO

Vietnamese smallholder dairy cows (VDC) are the result of crossbreeding between different zebu (ZEB) and taurine dairy breeds through many undefined generations. Thus, the predominant breed composition of VDC is currently unknown. This study aimed to evaluate the level of genetic diversity and breed composition of VDC. The SNP data of 344 animals from 32 farms located across four dairy regions of Vietnam were collected and merged with genomic reference data, which included three ZEB breeds: Red Sindhi, Sahiwal and Brahman, three taurine breeds: Holstein (HOL), Jersey (JER) and Brown Swiss (BSW), and a composite breed: Chinese Yellow cattle. Diversity and admixture analyses were applied to the merged data set. The VDC were not excessively inbred, as indicated by very low inbreeding coefficients (Wright's FIS ranged from -0.017 to 0.003). The genetic fractions in the test herds suggested that the VDC are primarily composed of HOL (85.0%); however, JER (6.0%), BSW 5.3%) and ZEB (4.5%) had also contributed. Furthermore, major genotype groupings in the test herds were pure HOL (48%), B3:15/16HOL_1/16ZEB (22%) and B2:7/8HOL_1/8ZEB (12%). The genetic makeup of the VDC is mainly components of various dairy breeds but also has a small percentage of ZEB; thus, the VDC could be a good genetic base for selecting high milk-producing cows with some degree of adaptation to tropical conditions.


Assuntos
Bovinos , Genoma , Leite , Animais , Cruzamento , Bovinos/genética , Feminino , Genômica , Genótipo , Vietnã
7.
Trop Anim Health Prod ; 54(5): 313, 2022 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-36131188

RESUMO

This study aimed to rank potential drivers of cow productivity and welfare in tropical smallholder dairy farms (SDFs) in Vietnam. Forty-one variables were collected from 32 SDFs located in four geographically diverse dairy regions, with eight SDFs per region. Twelve variables, including milk yield (MILK), percentages of milk fat (mFA), protein (mPR), dry matter (mDM), energy-corrected milk yield (ECM), heart girth (HG), body weight (BW), ECM per 100 kg BW (ECMbw), body condition score (BCS), panting score (PS), inseminations per conception (tAI), and milk electrical resistance (mRE) of cows, were fitted as outcome variables in the models. Twenty-one other variables describing farm altitude, housing condition, and diet for the cows, cow genotypes, and cow physiological stage were fitted as explanatory variables. Increased farm altitude was associated with increases in ECM and mRE and with decreases in PS and tAI (P < 0.05). Increases in roof heights and percentage of shed side open were associated with increases in ECM, mFA, and mDM (P < 0.05). Increased dry matter intake and dietary densities of dry matter and fat were associated with increased MILK, ECM, and ECMbw and decreased tAI (P < 0.05). Increased dietary lignin density was associated with increased PS. Increased genetic proportion of Brown Swiss in the herd was associated with increased MILK, ECM, and ECMbw (P < 0.05). Thus, to improve cow productivity and welfare in Vietnamese SDFs, the following interventions were identified for testing in future cause-effect experiments: increasing floor area per cow, roof heights, shed sides open, dry matter intake, dietary fat density, and the genetic proportion of Brown Swiss and decreasing dietary lignin density.


Assuntos
Lignina , Leite , Animais , Peso Corporal , Bovinos , Indústria de Laticínios , Dieta/veterinária , Fazendas , Feminino , Lactação , Lignina/metabolismo , Leite/metabolismo , Análise Multivariada , Vietnã
8.
Rheumatology (Oxford) ; 60(7): 3199-3208, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33355338

RESUMO

OBJECTIVES: ANCA-associated vasculitis (AAV) usually involves the renal and respiratory systems, but the paediatric literature on pulmonary manifestations and outcomes is limited. We aimed to describe pulmonary manifestations and outcomes after therapy in a cohort of paediatric AAV (pAAV) patients. METHODS: A retrospective chart review of all patients <19 years presenting to our institution with AAV between 1/2008 and 2/2018 was conducted. Patient demographics, clinical presentation, diagnostic testing, therapy and pulmonary outcomes over the first 3 years after presentation were evaluated. RESULTS: A total of 38 patients were included; all had ANCA positivity by immunofluorescence. A total of 23 had microscopic polyangiitis (MPA), 13 had granulomatosis with polyangiitis and 2 had eosinophilic granulomatosis with polyangiitis. A total of 30 (79%) had pulmonary manifestations, with cough (73%) and pulmonary haemorrhage (67%) being the most common. Abnormalities were noted in 82% of chest CT scans reviewed, with nodules and ground-glass opacities being the most common. At 6, 12 and 36 months follow-up, respectively, 61.8%, 39.4% and 29% of patients continued to show pulmonary manifestations. Five MPA patients with re-haemorrhage are described in detail. CONCLUSION: MPA was more common than granulomatosis with polyangiitis, with pulmonary involvement being common in both. MPA patients had more severe pulmonary manifestations. Chest CT revealed abnormal findings in a majority of cases. A subgroup of young MPA patients experienced repeat pulmonary haemorrhage. Treatment modality and response were comparable in different subtypes of AAV, except for this young MPA group. Additional prospective studies are needed to better understand the different phenotypes of pAAV.


Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/fisiopatologia , Tosse/fisiopatologia , Hemoptise/fisiopatologia , Hemorragia/fisiopatologia , Pneumopatias/fisiopatologia , Nódulos Pulmonares Múltiplos/fisiopatologia , Adolescente , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/imunologia , Autoanticorpos/imunologia , Criança , Pré-Escolar , Síndrome de Churg-Strauss/imunologia , Síndrome de Churg-Strauss/fisiopatologia , Estudos de Coortes , Progressão da Doença , Feminino , Granulomatose com Poliangiite/imunologia , Granulomatose com Poliangiite/fisiopatologia , Hemoptise/imunologia , Hemorragia/imunologia , Humanos , Lactente , Pneumopatias/diagnóstico por imagem , Pneumopatias/imunologia , Masculino , Poliangiite Microscópica/imunologia , Poliangiite Microscópica/fisiopatologia , Nódulos Pulmonares Múltiplos/diagnóstico por imagem , Mieloblastina/imunologia , Peroxidase/imunologia , Recidiva , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
9.
Intern Med J ; 51(1): 69-77, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31985128

RESUMO

BACKGROUND: Studies have reported significant differences in baseline characteristics and outcomes of metastatic colorectal cancer (mCRC) patients when managed in private versus public hospitals. AIMS: To compare disease, treatment and survival outcomes of patients with mCRC in public versus private hospitals in South Australia (SA). METHODS: Analysis of prospectively collected data from the SA mCRC Registry. Patterns of care and outcome data according to location of care and socioeconomic status based on Index of Relative Socio-Economic Advantage and Disadvantage were analysed. RESULTS: A total of 3470 patients' data was analysed during February 2006-January 2015. The majority (70%) of patients received treatment in public hospitals. Patients in the upper 50% for Index of Relative Socio-Economic Advantage and Disadvantage score were more likely to receive treatment at a private hospital (41.2% vs 21.56%) compared to <50%. Public patients had higher burden of disease (10.49% vs 7.41%, P = 0.005). Public patients received less treatment compared to the private patients (odds ratio = 0.48 (0.38-0.61), P = 0.01) and rates of surgical resections were lower in public patients. After adjusting for the covariates, public patients survive 1.33 months (P = 0.025) shorter than private patients with follow-up time of 5 years. Patients receiving metastasectomy and more than three lines of treatment were shown to have the greatest survival benefit. CONCLUSION: Public patients have a higher burden of disease and in comparison are less likely to receive systemic therapy and have lower survival than patients treated in private hospitals.


Assuntos
Neoplasias Colorretais , Austrália , Neoplasias Colorretais/epidemiologia , Neoplasias Colorretais/terapia , Hospitais Privados , Hospitais Públicos , Humanos , Sistema de Registros , Austrália do Sul/epidemiologia , Resultado do Tratamento
10.
Pharm Res ; 37(9): 174, 2020 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-32856172

RESUMO

PURPOSE: To apply a simple and flexible manufacturing technique, two-photon polymerisation (2PP), to the fabrication of microneedle (MN) array templates with high precision and low cost in a short time. METHODS: Seven different MN array templates were produced by 2PP 3D printing, varying needle height (900-1300 µm), shape (conical, pyramidal, cross-shaped and with pedestal), base width (300-500 µm) and interspacing (100-500 µm). Silicone MN array moulds were fabricated from these templates and used to produce dissolving and hydrogel-forming MN arrays. These polymeric MN arrays were evaluated for their insertion in skin models and their ability to deliver model drugs (cabotegravir sodium and ibuprofen sodium) to viable layers of the skin (ex vivo and in vitro) for subsequent controlled release and/or absorption. RESULTS: The various templates obtained with 2PP 3D printing allowed the reproducible fabrication of multiple MN array moulds. The polymeric MN arrays produced were efficiently inserted into two different skin models, with sharp conical and pyramidal needles showing the highest insertion depth values (64-90% of needle height). These results correlated generally with ex vivo and in vitro drug delivery results, where the same designs showed higher drug delivery rates after 24 h of application. CONCLUSION: This work highlights the benefits of using 2PP 3D printing to prototype variable MN array designs in a simple and reproducible manner, for their application in drug delivery.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Impressão Tridimensional/instrumentação , Pele/metabolismo , Administração Cutânea , Animais , Hidrogéis , Microinjeções/instrumentação , Modelos Biológicos , Agulhas , Polimerização , Polímeros/química , Suínos
12.
Nature ; 567(7748): S12-S17, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30894736
13.
Int J Biometeorol ; 64(9): 1583-1592, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32506160

RESUMO

Infrared thermography is a tool to investigate the welfare of cattle. This study aimed to identify a sampling strategy for recording infrared thermograms in dairy cows, in order to most efficiently determine biologically relevant changes in the maximum infrared temperature (IRT) of the eyes and coronary band of forelimbs. Thirty-one dairy cows were used for the study. They were assessed with four replicates of thermograms for each of the head and lower forelimb per cow for 6 mostly consecutive days (sessions). The data obtained were subjected to random effects Analysis of Variance which was used to estimate the variance components for this sampling model, using maximum IRT of both eyes; (left + right eye)/2 and both limbs; (left + right coronary band of forelimb)/2 as dependant variables. The variance components were used to calculate least significant differences (LSD) between two theoretical treatment groups under different sampling scenarios. Analysis showed that there was minimal improvement in precision beyond 2 thermograms within a session but there was improvement with increasing the number of sessions from 2 to 3. The LSD of both eyes and both limbs reached a biologically relevant difference (0.4 and 0.9 °C, respectively) at a minimum number of 14 - 16 cows monitored for 2 consecutive thermography sessions, or 10 - 12 cows for 3 sessions. We conclude that no more than 2 replicate IRT measures are required per session but that measuring on 3 consecutive days should be considered, depending on whether time or number of cows used is the primary limitation.


Assuntos
Temperatura Corporal , Termografia , Animais , Bovinos , Feminino , Monitorização Fisiológica , Temperatura
14.
Trop Anim Health Prod ; 53(1): 46, 2020 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-33241458

RESUMO

We used spontaneous behaviours to assess response to dry-off involving abrupt dietary and milking frequency changes, followed by regrouping, after the last milking in 15 clinically healthy Holstein-Frisian cows kept outdoors. Moreover, we explored the potential of infrared thermography to detect eye temperature variations possibly induced by dry-off. On days - 1, 0, 1 and 2 relative to dry-off, we recorded whether cows vocalised during feed delivery; ate fresh feed within 5 min; and mean maximum eye temperature at approximately 1 h after feed delivery. On days 1 and 2, cows were more likely to eat fresh feed compared to days - 1 and 0. No difference in likelihood of vocalising was found. Compared to day - 1, eye temperature was substantially higher on days 0 and 2. Collectively, the results suggest that cows responded, both behaviourally and physiologically, to the abrupt dry-off management. The interpretation of the current findings deserves further investigation using larger sample sizes, more controlled environments and further behavioural, physiological, cognitive and clinical measures.


Assuntos
Comunicação Animal , Temperatura Corporal , Bovinos/fisiologia , Indústria de Laticínios , Dieta/veterinária , Ingestão de Alimentos , Termografia/veterinária , Animais , Indústria de Laticínios/métodos , Feminino , Projetos Piloto
15.
J Neurosci ; 36(27): 7184-97, 2016 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-27383593

RESUMO

UNLABELLED: Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs, with five subtypes named M1-M5) are a unique subclass of RGCs with axons that project directly to many brain nuclei involved in non-image-forming functions such as circadian photoentrainment and the pupillary light reflex. Recent evidence suggests that melanopsin-based signals also influence image-forming visual function, including light adaptation, but the mechanisms involved are unclear. Intriguingly, a small population of M1 ipRGCs have intraretinal axon collaterals that project toward the outer retina. Using genetic mouse models, we provide three lines of evidence showing that these axon collaterals make connections with upstream dopaminergic amacrine cells (DACs): (1) ipRGC signaling to DACs is blocked by tetrodotoxin both in vitro and in vivo, indicating that ipRGC-to-DAC transmission requires voltage-gated Na(+) channels; (2) this transmission is partly dependent on N-type Ca(2+) channels, which are possibly expressed in the axon collateral terminals of ipRGCs; and (3) fluorescence microscopy reveals that ipRGC axon collaterals make putative presynaptic contact with DACs. We further demonstrate that elimination of M1 ipRGCs attenuates light adaptation, as evidenced by an impaired electroretinogram b-wave from cones, whereas a dopamine receptor agonist can potentiate the cone-driven b-wave of retinas lacking M1 ipRGCs. Together, the results strongly suggest that ipRGCs transmit luminance signals retrogradely to the outer retina through the dopaminergic system and in turn influence retinal light adaptation. SIGNIFICANCE STATEMENT: Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) comprise a third class of retinal photoreceptors that are known to mediate physiological responses such as circadian photoentrainment. However, investigation into whether and how ipRGCs contribute to vision has just begun. Here, we provide convergent anatomical and physiological evidence that axon collaterals of ipRGCs constitute a centrifugal pathway to DACs, conveying melanopsin-based signals from the innermost retina to the outer retina. We further demonstrate that retrograde signals likely influence visual processing because elimination of axon collateral-bearing ipRGCs impairs light adaptation by limiting dopamine-dependent facilitation of the cone pathway. Our findings strongly support the hypothesis that retrograde melanopsin-based signaling influences visual function locally within the retina, a notion that refutes the dogma that RGCs only provide physiological signals to the brain.


Assuntos
Potenciais da Membrana/fisiologia , Retina/citologia , Células Ganglionares da Retina/fisiologia , Visão Ocular/fisiologia , Vias Visuais/fisiologia , Animais , Animais Recém-Nascidos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/genética , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/metabolismo , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/genética , Feminino , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Luz , Masculino , Potenciais da Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas do Tecido Nervoso/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Células Ganglionares da Retina/classificação , Células Ganglionares da Retina/efeitos dos fármacos , Opsinas de Bastonetes/genética , Opsinas de Bastonetes/metabolismo , Bloqueadores dos Canais de Sódio/farmacologia , Tetrodotoxina/farmacologia , Transducina/genética , Transducina/metabolismo , Tirosina 3-Mono-Oxigenase/genética , Tirosina 3-Mono-Oxigenase/metabolismo , Visão Ocular/genética , beta-Galactosidase/metabolismo
16.
Eur J Appl Physiol ; 115(5): 905-10, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25488671

RESUMO

PURPOSE: Body weight-supported treadmill training using positive air pressure has become increasingly popular, but little is known about the metabolic adaptations to these treadmills. This study aimed to evaluate the existence and length of a metabolic accommodation period to running on a lower body positive pressure (LBPP) treadmill. METHODS: A total of eight recreational runners (5 males and 3 females) ran 15 min trials (5 min at 50, 70, and 90 % body weight) on the AlterG Anti-gravity(®) P200 treadmill. No verbal instruction was given on how to run on the device. Their trial pace corresponded to 70-80 % of their velocity measured at [Formula: see text]O2max on a standard treadmill. Trials were continued until no significant metabolic change was observed. Two-way repeated measures analysis of variance was used to analyze changes in [Formula: see text]O2 across trials and levels of unloading. RESULTS: Participants completed 7 trials. Comparing trial 1 to the average of trials 5, 6, and 7, [Formula: see text]O2 decreased from 29.6 ± 3.8 to 23.6 ± 4.4 ml/kg/min at 50 % body weight (~20 % reduction), from 33.7 ± 4.5 to 29.2 ± 5.1 ml/kg/min at 70 % body weight (~13 % reduction), and from 41.0 ± 7.7 to 36.6 ± 5.6 ml/kg/min at 90 % body weight (~11 % reduction). No significant reduction occurred after trial 4 at any level of support. CONCLUSIONS: An accommodation effect of running on a treadmill with LBPP was observed and reached after 60 min of running (4 trials of 15 min). The accommodation effect was the largest at the greatest level of body weight support. These data suggest the importance of an accommodation period for reliable measures of metabolic cost to be made.


Assuntos
Peso Corporal/fisiologia , Consumo de Oxigênio/fisiologia , Corrida/fisiologia , Adulto , Composição Corporal , Metabolismo Energético , Teste de Esforço , Feminino , Humanos , Masculino , Adulto Jovem
17.
J Strength Cond Res ; 29(3): 863-8, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25226319

RESUMO

Body weight (BW)-supported treadmill training has become increasingly popular in professional sports and rehabilitation. To date, little is known about the accuracy of the lower-body positive pressure treadmill. This study evaluated the accuracy of the BW support reported on the AlterG "Anti-Gravity" Treadmill across the spectrum of unloading, from full BW (100%) to 20% BW. Thirty-one adults (15 men and 16 women) with a mean age of 29.3 years (SD = 10.9), and a mean weight of 66.55 kg (SD = 12.68) were recruited. Participants were weighed outside the machine and then inside at 100-20% BW in 10% increments. Predicted BW, as presented by the AlterG equipment, was compared with measured BW. Significant differences between predicted and measured BW were found at all but 90% through 70% of BW. Differences were small (<5%), except at the extreme ends of the unloading spectrum. At 100% BW, the measured weight was lower than predicted (mean = 93.15%, SD = 1.21, p < 0.001 vs. predicted). At 30 and 20% BW, the measured weight was higher than predicted at 35.75% (SD = 2.89, p < 0.001), and 27.67% (SD = 3.76, p < 0.001), respectively. These findings suggest that there are significant differences between reported and measured BW support on the AlterG Anti-Gravity Treadmill®, with the largest differences (>5%) found at 100% BW and the greatest BW support (30 and 20% BW). These differences may be associated with changes in metabolic demand and maximum speed during walking or running and should be taken into consideration when using these devices for training and research purposes.


Assuntos
Peso Corporal/fisiologia , Teste de Esforço/instrumentação , Adulto , Calibragem , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
18.
J Strength Cond Res ; 29(3): 854-62, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25162650

RESUMO

Lower body positive pressure (LBPP) or antigravity treadmills are becoming increasingly popular in sports and rehabilitation settings. Running at a decreased body weight (BW) reduces metabolic cost, which can be offset by running at faster speeds. To date, however, little is known about how much faster someone must run to offset the reduced metabolic cost. This study aimed to develop a user-friendly conversion table showing the speeds required on an LBPP treadmill to match the equivalent metabolic output on a regular, non-LBPP, treadmill across a range of body weight supports. A total of 20 recreational runners (11 males, 9 females) ran multiple 3-minute intervals on a regular treadmill and then on an LBPP treadmill at 6 different BWs (50-100%, 10% increments). Metabolic outputs were recorded and matched between the regular and LBPP treadmill sessions. Using regression analyses, a conversion table was successfully created for the speeds from 6.4 to 16.1 km·h (4 to 10 mph) in 0.8 km·h (0.5 mph) increments on the regular treadmill and BW proportions of 50, 60, 70, 80, 90, and 100% on an LBPP treadmill. The table showed that a greater increase in speed on the LBPP treadmill was needed with more support (p < 0.001) but that the proportion increase was smaller at higher speeds (p < 0.001). This research has implications for coaches or practitioners using or prescribing training on an LBPP treadmill.


Assuntos
Teste de Esforço/instrumentação , Consumo de Oxigênio/fisiologia , Corrida/fisiologia , Adulto , Desenho de Equipamento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Valores de Referência , Análise de Regressão , Adulto Jovem
19.
J Sports Sci Med ; 14(2): 333-9, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25983582

RESUMO

Lower body positive pressure (LBPP), or 'anti-gravity' treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS) on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile(-1) pace (3.35, 3.84, 4.47 and 5.36 m·s(-1)), while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00). One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (V̇O2) were found with each increase in BWS (p < 0.001). At 20% BWS, the average decrease in net VO2 was greater than proportional (34%), while at 40% BWS, the average net reduction in VO2 was close to proportional (38%). Across velocities, the slope of the relationship between VO2 and velocity (ΔV̇O2/Δv) was steeper with less support. The slopes at both the 20% and 40% BWS conditions were similar, especially when compared to the regular treadmill. Variability in VO2 between athletes was much greater on the LBPP treadmill and was greater with increased levels of BWS. In this study we evaluated the effect of body weight support on V̇O2 among elite distance runners. We have shown that oxygen uptake decreased with support, but not in direct proportion to that support. Further, because of the high variability in oxygen uptake between athletes on the LBPP treadmill, prediction equations may not be reliable and other indicators (heart rate, perceived exertion or directly measured oxygen uptake) should be used to guide training intensity when training on the LBPP treadmill. Key pointsWith increasing amounts of body weight-support (BWS), the slope of the relationship between velocity and oxygen consumption (ΔVO2/Δv) decreases significantly. This means the change in oxygen consumption (VO2) is significantly smaller over a given change in velocity at higher amounts of BWS.There is a non-linear decrease in VO2 with increasing BWS. As such, with each increment in the amount of BWS provided, the reduction in VO2 becomes increasingly smaller.This paper provides first of its kind data on the effects of BWS on the cost of running among highly trained, elite runners. The outcomes of this study are in line with previous findings among non-elite runners.

20.
ACS Meas Sci Au ; 4(2): 201-212, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38645576

RESUMO

In this study, a micro helium dielectric barrier discharge (µHDBD) plasma device fabricated using 3D printing and molding techniques was coupled with a mini spectrometer to detect and identify different classes of volatile organic compounds (VOCs) using optical emission spectrometry (OES). We tested 11 VOCs belonging to three different classes (straight-chain alkanes, aromatics, and polar organic compounds). Our results clearly demonstrate that the optical emission spectra of different classes of VOCs show clear differences, and therefore, can be used for identification. Additionally, the emission spectra of VOCs with a similar structure (such as n-pentane, n-hexane, n-heptane, n-octane, and n-nonane) have similar optical emission spectrum shape. Acetone and ethanol also have similar emission wavelengths, but they show different line intensities for the same concentrations. We also found that the side-chain group of aromatics will also affect the emission spectra even though they have a similar structure (all have a benzene ring). Moreover, our µHDBD-OES system can also identify multiple compounds in VOC mixtures. Our work also demonstrates the possibility of identifying different classes of VOCs by the OES shape.

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