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1.
ACS Omega ; 5(27): 16455-16459, 2020 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-32685809

RESUMO

The recirculation of gases in a sealed reactor system is a broadly useful method in catalytic and electrocatalytic studies. It is especially relevant when a reactant gas reacts slowly with respect to residence time in a catalytic reaction zone and when mass transport control through the reaction zone is necessary. This need is well illustrated in the field of electrocatalytic N2 reduction, where the need for recirculation of 15N2 has recently become more apparent. Herein, we describe the design, fabrication, use, and specifications of a lubricant-free, readily constructed recirculating pump fabricated entirely from glass and inert polymer (poly(ether ether ketone) (PEEK), poly(tetrafluoroethylene) (PTFE)) components. Using these glass and polymer components ensures chemical compatibility between the piston pump and a wide range of chemical environments, including strongly acidic and organic electrolytes often employed in studies of electrocatalytic N2 reduction. The lubricant-free nature of the pump and the presence of components made exclusively of glass and PEEK/PTFE mitigate contamination concerns associated with recirculating gases saturated with corrosive or reactive vapors for extended periods. The gas recirculating glass pump achieved a flow rate of >500 mL min-1 N2 against atmospheric pressure at 15 W peak power input and >100 mL min-1 N2 against a differential pressure of +6 in. H2O (∼15 mbar) at 10 W peak power input.

2.
Materials (Basel) ; 13(2)2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31936172

RESUMO

Keywords: WeldForming; post weld treatment; recrystallization; thermomechanical simulation; numerical simulation; FEM.

3.
Artif Organs ; 42(7): 723-727, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29611214

RESUMO

In renal transplantation, ischemia reperfusion injury impairs early graft function and can reduce long term graft survival. Hydrogen has antioxidant and anti-inflammatory properties that can reduce the effects of ischemic injury. The aim of this study was to examine the effects of hydrogen gas administered during reperfusion in a preclinical model of kidney ischemia reperfusion injury. Porcine kidneys underwent 15 min of warm ischemia followed by 22 h of cold ischemia. They were then reperfused for 6 h with whole autologous blood on an ex vivo reperfusion circuit. Paired kidneys were randomized to control (n = 6) (25% oxygen, 5% carbon dioxide, 70% nitrogen) or hydrogen (n = 6) (2% hydrogen, 25% oxygen, 5% carbon dioxide, 68% nitrogen) groups. Tissue, urine, and blood samples were collected at baseline and hourly throughout the reperfusion period. Baseline measurements were similar across groups. Following perfusion, there was no significant difference between control and hydrogen groups in urine output (693 mL vs. 608 mL, P = 0.86), renal blood flow (105.9 vs. 108 mL/min/100g, P = 0.89), acid-base homeostasis, or creatinine clearance. There was a significant increase in cytokine levels from baseline to 6 h in both groups (IL-1ß P = 0.002; IL-6 P = 0.004; IL-8 P = 0.002). However, there were no significant differences in levels of inflammatory cytokines (IL1ß, IL-6, and IL-8) between the groups. The administration of hydrogen gas did not improve renal function, reduce oxidative damage, or inflammation during the reperfusion of ischemically damaged kidneys.


Assuntos
Hidrogênio/uso terapêutico , Traumatismo por Reperfusão/terapia , Animais , Isquemia Fria , Modelos Animais de Doenças , Rim/fisiopatologia , Transplante de Rim , Estresse Oxidativo , Circulação Renal , Traumatismo por Reperfusão/sangue , Traumatismo por Reperfusão/fisiopatologia , Traumatismo por Reperfusão/urina , Suínos , Isquemia Quente
4.
Health Promot Pract ; 19(6): 896-904, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29388480

RESUMO

In 2003, Arkansas became the first state to require body mass index (BMI) testing in public schools to raise awareness of the growing obesity epidemic among children and adolescents. Limited information exists regarding the effectiveness of school-based BMI screening programs. The purpose of this study was to determine if BMI health report cards affected parents' knowledge or actions regarding their child's health and to determine the accuracy of parents' perceptions of their child as underweight, normal weight, or overweight according to their child's BMI. A questionnaire was developed with the help of physical educators, pediatricians, and exercise scientists to determine parents' perceptions and behaviors regarding BMI report cards. The questionnaire was distributed to parents/guardians of children who sought medical care at two pediatrician's offices in Arkansas. Based on responses to survey questions, parents are not making changes to their child's diet and exercise habits if their child is classified as "at risk" or "overweight." However, parents did report that BMI health report cards are influencing their knowledge about their child's health. The majority of parents in the study (approximately 66%) did not accurately perceive their child's BMI category.


Assuntos
Índice de Massa Corporal , Conhecimentos, Atitudes e Prática em Saúde , Promoção da Saúde/organização & administração , Sobrepeso/prevenção & controle , Pais/psicologia , Adolescente , Adulto , Arkansas/epidemiologia , Peso Corporal , Criança , Pré-Escolar , Dieta , Exercício Físico , Feminino , Humanos , Masculino , Relações Pais-Filho , Percepção , Inquéritos e Questionários
5.
J Transl Med ; 15(1): 216, 2017 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-29070045

RESUMO

BACKGROUND: Ex-vivo normothermic perfusion strategies are a promising new instrument in organ transplantation. The perfusion conditions are designed to be protective however the artificial environment can induce a local inflammatory response. The aim of this study was to determine the effect of incorporating a Cytosorb adsorber into an isolated kidney perfusion system. METHODS: Porcine kidneys were subjected to 22 h of cold ischaemia then reperfused for 6 h on an ex vivo reperfusion circuit. Pairs of kidneys were randomised to either control (n = 5) or reperfusion with a Cytosorb adsorber (n = 5) integrated into the circuit. Tissue, blood and urine samples were taken for the measurement of inflammation and renal function. RESULTS: Baseline levels of cytokines (IL-6, TNFα, IL-8, IL-10, IL-1ß, IL-1α) were similar between groups. Levels of IL-6 and IL-8 in the perfusate significantly increased during reperfusion in the control group but not in the Cytosorb group (P = 0.023, 0.049). Levels of the other cytokines were numerically lower in the Cytosorb group; however, this did not reach statistical significance. The mean renal blood flow (RBF) was significantly higher in the Cytosorb group (162 ± 53 vs. 120 ± 35 mL/min/100 g; P = 0.022). Perfusate levels of prostaglandin E2 were significantly lower in the Cytosorb group (642 ± 762 vs. 3258 ± 980 pg/mL; P = 0.0001). Levels of prostacyclin were significantly lower in the Cytosorb group at 1, 3 and 6 h of reperfusion (P = 0.008, 0.003, 0.0002). Levels of thromboxane were also significantly lower in the Cytosorb group throughout reperfusion (P = 0.005). Haemoadsorption had no effect on creatinine clearance (P = 0.109). CONCLUSION: Haemoadsorption can reduce the inflammatory response and improve renal blood flow during perfusion. Nonetheless, in this model haemoadsorption had no influence on renal function and this may relate to the broad-spectrum action of the Cytosorb adsorber that also removes potentially important anti-inflammatory mediators.


Assuntos
Hemodinâmica , Inflamação/patologia , Rim/irrigação sanguínea , Rim/fisiologia , Perfusão , Adsorção , Animais , Citocinas/metabolismo , Regulação da Expressão Gênica , Hematócrito , Heme/metabolismo , Hemoglobinas/metabolismo , Inflamação/sangue , Inflamação/genética , Testes de Função Renal , Contagem de Leucócitos , Modelos Animais , Contagem de Plaquetas , Fluxo Sanguíneo Regional , Sus scrofa
6.
Br J Hosp Med (Lond) ; 73(2): 72-8, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22504748

RESUMO

The increasing popularity of mass participation endurance events necessitates that on-site medical teams be well versed in the management of both common and life-threatening conditions. Exertional heat stroke is one such condition, which if left untreated can be fatal.


Assuntos
Golpe de Calor/fisiopatologia , Golpe de Calor/terapia , Temperatura Alta/efeitos adversos , Esforço Físico , Regulação da Temperatura Corporal/fisiologia , Sistema Cardiovascular/fisiopatologia , Protocolos Clínicos , Exercício Físico/fisiologia , Hidratação , Golpe de Calor/diagnóstico , Humanos , Fatores de Risco
7.
J Strength Cond Res ; 25(10): 2926-30, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21912281

RESUMO

Sampling sites for determining lactate concentration [La(-)] have been debated for years. To date, none of the research that has been completed has taken into consideration the muscle group that is active during exercise, sample site, and the passivity of nonexercising muscle, collectively. The purpose of this study was to determine if this passive sink phenomenon could be visualized by using common sampling methods immediately after exercise and during the recovery period from 2 sample sites. Eleven male cyclists completed a subject-specific trial on a Velotron cycle ergometer. Plasma [La(-)] was measured from the finger and toe immediately postexercise and every 5 minutes after, for 25 minutes after the cycling trial. All 3 analyses were significant (p < 0.05) with the sample site × sample time interaction, sample time main effect, and sample site main effect being reported, respectively: Wilks' λ = 0.079, F (5,6) = 13.932, p = 0.003, Wilks' λ = 0.012, F (5,6) = 94.804, p = 0.000, and Wilks' λ = 0.492, F (1,10) = 10.316, p = 0.009. Post hoc paired t-tests on computed mean differences between sample sites for each sample time revealed statistically significant differences (p < 0.05) between several time intervals. Further analysis also revealed significant differences (p < 0.05) in the sample site main effect at each collection time. Blood lactate samples need to be obtained from the limb containing the exercising muscle(s) to negate the passive sink effect that has been observed to occur in nonexercising muscles. This recommendation needs to be followed to better establish future training volumes and outcomes.


Assuntos
Coleta de Amostras Sanguíneas/métodos , Exercício Físico/fisiologia , Ácido Láctico/sangue , Músculo Esquelético/fisiologia , Atletas , Teste de Esforço , Dedos , Humanos , Masculino
8.
Exp Eye Res ; 90(2): 368-72, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19833124

RESUMO

A population of peripheral retinal pigment epithelium (RPE) cells in mature pigmented rats are retained in the cell cycle and divide, as determined by Ki67 and BrdU labeling. Their cell cycle rate is approximately 5 days. Ten times as many Ki67 positive cells are found in albinos compared with pigmented animals, but it is not known if they actually divide or only express cell cycle markers. In spite of the increased number of cells expressing cell cycle markers, we show here using BrdU, that levels of cell division in albino RPE are similar to those in pigmented animals and have a similar cell cycle rate. Hence, cell cycle activity does not progress through to cell division in the majority of albino RPE cells. Peripheral RPE cells in albinos are different from those in pigmented animals. Many have very large distorted or highly fragmented nuclei. These data along with patterns of Ki67 and BrdU labeling are consistent with such cells being retained abnormally in the cell cycle, replicating their DNA, but not able to progress through to full cell division. Hence, there are two populations of RPE cells in albinos, those undergoing normal cell division and those that appear to be arrested in the cell cycle. These abnormalities are present from early postnatal stages.


Assuntos
Albinismo Oculocutâneo/patologia , Ciclo Celular , Epitélio Pigmentado da Retina/patologia , Albinismo Oculocutâneo/metabolismo , Animais , Bromodesoxiuridina , Núcleo Celular/patologia , Proliferação de Células , Antígeno Ki-67/metabolismo , Poliploidia , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Epitélio Pigmentado da Retina/metabolismo
9.
Proc Natl Acad Sci U S A ; 104(42): 16450-5, 2007 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-17923671

RESUMO

Commercially improved crop performance under drought conditions has been challenging because of the complexity of the trait and the multitude of factors that influence yield. Here we report the results of a functional genomics approach that identified a transcription factor from the nuclear factor Y (NF-Y) family, AtNF-YB1, which acts through a previously undescribed mechanism to confer improved performance in Arabidopsis under drought conditions. An orthologous maize transcription factor, ZmNF-YB2, is shown to have an equivalent activity. Under water-limited conditions, transgenic maize plants with increased ZmNF-YB2 expression show tolerance to drought based on the responses of a number of stress-related parameters, including chlorophyll content, stomatal conductance, leaf temperature, reduced wilting, and maintenance of photosynthesis. These stress adaptations contribute to a grain yield advantage to maize under water-limited environments. The application of this technology has the potential to significantly impact maize production systems that experience drought.


Assuntos
Proteínas de Arabidopsis/fisiologia , Arabidopsis/genética , Fator de Ligação a CCAAT/fisiologia , Desastres , Proteínas de Plantas/fisiologia , Plantas Geneticamente Modificadas/genética , Fatores de Transcrição/fisiologia , Água , Zea mays/genética , Proteínas de Arabidopsis/genética , Fator de Ligação a CCAAT/genética , Genômica , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Subunidades Proteicas/genética , Subunidades Proteicas/fisiologia , Fatores de Transcrição/genética , Zea mays/crescimento & desenvolvimento
10.
Transgenic Res ; 13(5): 451-61, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15587269

RESUMO

By introducing additional T-DNA borders into a binary plasmid used in Agrobacterium-mediated plant transformation, previous studies have demonstrated that the marker gene and the gene of interest (GOI) can be carried by independent T-strands, which sometimes integrate in unlinked loci in the plant genome. This allows the recovery of marker-free transgenic plants through genetic segregation in the next generation. In this study, we have found that by repositioning the selectable marker gene in the backbone and leaving only the GOI in the T-DNA region, a regular two-border binary plasmid was able to generate marker-free transgenic maize plants more efficiently than a conventional single binary plasmid with multiple T-DNA borders. These results also provide evidence that both the right and left borders can initiate and terminate T-strands. Such non-canonical initiation and termination of T-strands may be the basis for the elevated frequencies of cotransformation and unlinked insertions.


Assuntos
Agrobacterium tumefaciens/genética , Plasmídeos/genética , Transformação Genética , Zea mays/genética , DNA de Plantas/genética , Genes Reporter/genética , Plantas Geneticamente Modificadas/genética , Recombinação Genética
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