Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 291
Filtrar
1.
Am J Obstet Gynecol MFM ; 5(2): 100815, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36400421

RESUMO

BACKGROUND: Preeclampsia affects between 2% and 5% of pregnancies and is one of the leading causes of perinatal morbidity and mortality worldwide. Despite strong evidence that the combination of systematic preeclampsia screening based on the Fetal Medicine Foundation preeclampsia risk calculation algorithm with treatment of high-risk patients with low-dose aspirin reduces the incidence of preterm preeclampsia more than currently used risk-factor-based screening, real-world implementation studies have not yet been done in Canada. OBJECTIVE: This study aimed to assess the operational feasibility of implementing first-trimester screening and prevention of preterm preeclampsia (<37 weeks) alongside a publicly funded first-trimester combined screening program for aneuploidies. STUDY DESIGN: This was a prospective implementation study. Consecutive pregnant patients referred for first-trimester combined screening (11-13+6 weeks) were offered screening for preeclampsia based on the Fetal Medicine Foundation algorithm concomitantly with their aneuploidy screen. Consenting participants were screened using maternal risk factors, mean arterial pressure, uterine artery Doppler pulsatility index, pregnancy-associated plasma protein-A, and placental growth factor. Risk for preterm preeclampsia (<37 weeks) was calculated using the Fetal Medicine Foundation algorithm, and individuals with a risk score ≥1 per 100 were recommended to use aspirin (162 mg once daily at bedtime, <16-36 weeks). Implementation metrics assessed included: acceptability, operational impact, proportion of aspirin initiation, quality and safety measures, and screen performance. RESULTS: Between December 1, 2020 and April 23, 2021, 1124 patients consented to preeclampsia screening (98.3% uptake), and 92 (8.2%) screened positive. Appointments for patients receiving first-trimester combined screening aneuploidy and preeclampsia screening averaged 6 minutes longer than first-trimester combined screening alone, and adding uterine artery Doppler pulsatility index averaged 2 minutes. Of the 92 patients who screened as high-risk for preeclampsia, 72 (78.3%) were successfully contacted before 16 weeks' gestation. Of these, 62 (86.1%) initiated aspirin, and 10 (13.9%) did not. Performance audit identified a consistent negative bias with mean arterial pressure measurements (median multiple of the median <1 in 10%); other variables were satisfactory. There were 7 cases of preterm preeclampsia (0.69%): 5 and 2 in the high- and low-risk groups, respectively. Screening detected 5 of 7 (71.4 %) preterm preeclampsia cases, with improved performance after adjustment for aspirin treatment effect. CONCLUSION: This study confirms the operational feasibility of implementing an evidence-based preeclampsia screening and prevention program in a publicly funded Canadian setting. This will facilitate implementation into clinical service and the scaling up of this program at a regional and provincial level.


Assuntos
Pré-Eclâmpsia , Gravidez , Recém-Nascido , Humanos , Feminino , Pré-Eclâmpsia/diagnóstico , Pré-Eclâmpsia/epidemiologia , Pré-Eclâmpsia/prevenção & controle , Estudos Prospectivos , Medição de Risco , Fator de Crescimento Placentário , Canadá , Aspirina/uso terapêutico , Aneuploidia
2.
Cytokine ; 157: 155965, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35843124

RESUMO

The purpose of this study was to determine whether six weeks of high intensity interval training (HIIT) would lead to greater changes in resting concentrations of salivary IL-8 and IL-1ra than moderate intensity continuous training (MICT) in young, healthy adults, and to determine whether changes in IL-8 and IL-1ra after six weeks of either HIIT or MICT were associated with changes in maximal exercise capacity (VO2max). Participants were randomly assigned to 6 weeks of HIIT (n = 12) or MICT (n = 11), matched for workload. Saliva samples were collected at the beginning (T1) and end (T2) of the intervention, and analyzed for IL-8 and IL-1ra. Participants in both groups had significant improvements in VO2max; there were no group differences in improvements. A greater reduction in IL-8 was observed in the MICT group when compared to the HIIT group (HIIT median: -9.5; MICT median: -82.3 pg/µg of protein; U = 11.5, p < 0.001). When combining the HIIT and MICT group, there were significant reductions in IL-8 from T1 to T2. There was no correlation between changes in IL-8 (r < 0.00) or IL-1ra (r = -0.013) with changes in VO2max. In conclusion, 6 weeks of exercise training leads to a reduction in IL-8; MICT may lead to greater reductions when compared to HIIT. Future research examining longer intervention periods is needed to further elucidate the effects of HIIT and MICT on different pro and anti-inflammatory cytokines.


Assuntos
Treinamento Intervalado de Alta Intensidade , Adulto , Exercício Físico , Humanos , Proteína Antagonista do Receptor de Interleucina 1 , Interleucina-8 , Consumo de Oxigênio
3.
J Interprof Care ; 35(3): 376-382, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32400226

RESUMO

The rapid growth in the proportion of adults over the age of 65 translates into greater need of complex, highly specialized care. Hence, coupled with other factors, healthcare expenditures in Canada have grown exponentially, creating tension for a high-quality care while managing costs. Interventions with community-based interprofessional teams have been piloted across Canada as a means to provide efficient specialized care. These teams must, however, work collaboratively for a more comprehensive and patient-centered care. This metasynthesis aimed to identify common factors or characteristics found to be essential for a collaborative practice among members of an interdisciplinary team delivering coordinated care to community-dwelling seniors in both rural and urban centers in Canada. Six databases (Medline, CINAHL, Sage, JSTOR, ProQuest, Web of Science) were searched for qualitative peer-reviewed articles on community-based interventions with interprofessional teams in Canada and published between 2005-2018. Six articles were included and appraised using the COREQ guidelines for quality, followed by a thematic analysis for common themes related to team collaboration. Overarching themes related to practices of interprofessional collaboration were trust and respect, communication, and shared vision. Sub-themes included trust in the relationship between health care professional, professional identity and role clarity, interprofessional communication, communication with the client or family, and common goals. Interprofessional teams work collaboratively when trust and respect, communication, and shared vision are valued and present. Agencies coordinating interprofessional teams for community-based care could be pivotal in ensuring an environment conducive to collaboration, such as learning and team building opportunities.


Assuntos
Vida Independente , Relações Interprofissionais , Equipe de Assistência ao Paciente , Adulto , Canadá , Comportamento Cooperativo , Pessoal de Saúde , Serviços de Saúde para Idosos , Humanos , Pesquisa Qualitativa
4.
J Dairy Sci ; 103(7): 5805-5815, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32448573

RESUMO

Lactic acid bacteria (LAB) are used as starter cultures in the production of fermented dairy products and have the potential to confer bioactivity relevant to cardiovascular health, as they possess extensive proteolytic systems that liberate small bioactive peptides from larger milk proteins. Certain casein-derived peptides released by various LAB strains during fermentation have been shown to reduce hypertension and to modulate the immune system. We investigated the growth and peptide production of 2 LAB strains, Lactobacillus helveticus R0389 and Lactocaseibacillus rhamnosus R0011, their immunomodulatory activities, as well as their abilities to inhibit the angiotensin-converting enzyme (ACE). Peptide fractions collected from the cell-free supernatant of both medium-grown and milk fermentation cultures were assessed for ACE-inhibitory activity and their effects on the production of proinflammatory and regulatory cytokines by human THP-1 monocytes. Cultures were grown in medium, with or without supplementation with 0.1% casein, or in 3.25% milk fermented with each LAB strain. Casein supplementation increased the growth rate of both LAB strains, and significantly increased ACE-inhibitory activity of peptide fractions collected from both L. helveticus R0389 and L. rhamnosus R0011 cultures grown for 12 h. Fermentation peptide fractions of L. rhamnosus R0011 showed comparable ACE-inhibitory activity to known ACE inhibiting peptides Val-Pro-Pro and Ile-Pro-Pro (up to 79% inhibition) with a significant difference between culture peptide fractions and acidified and nonacidified control fractions collected after 6 d of fermentation. Many milk and casein-derived peptides reported in previous studies have been identified as part of a larger bioactive fraction. We synthesized a group of these peptides to individually assess both ACE-inhibitory and immunomodulatory activity. The known ACE inhibitors Val-Pro-Pro and Ile-Pro-Pro showed similar ACE inhibition to previously published results, while also inducing the production of the regulatory cytokine IL-10 by monocytes in the presence and absence of a proinflammatory stimulant. These synthesized peptides could also induce the production of nitric oxide (NO), a potent vasodilator, in human endothelial cell cultures. Investigating the relationships among these bioactive properties could improve the use of probiotic organisms and their secreted products in the food industry.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Proteínas de Bactérias/farmacologia , Lacticaseibacillus rhamnosus/química , Lactobacillus helveticus/química , Peptídeos/farmacologia , Peptidil Dipeptidase A/metabolismo , Inibidores da Enzima Conversora de Angiotensina/metabolismo , Proteínas de Bactérias/metabolismo , Caseínas/análise , Citocinas/metabolismo , Óxido Nítrico/metabolismo , Peptídeos/metabolismo
5.
Artigo em Inglês | MEDLINE | ID: mdl-31707090

RESUMO

Adolescence is a developmental period marked by robust neural alterations and heightened vulnerability to stress, a factor that is highly associated with increased risk for emotional processing deficits, such as anxiety. Stress-induced upregulation of the dynorphin/kappa opioid receptor (DYN/KOP) system is thought to, in part, underlie the negative affect associated with stress. The basolateral amygdala (BLA) is a key structure involved in anxiety, and neuromodulatory systems, such as the DYN/KOP system, can 1) regulate BLA neural activity in an age-dependent manner in stress-naïve animals and 2) underlie stress-induced anxiety in adults. However, the role of the DYN/KOP system in modulating stress-induced anxiety in adolescents is unknown. To test this, we examined the impact of an acute, 2-day forced swim stress (FSS - 10 min each day) on adolescent (~postnatal day (P) 35) and adult Sprague-Dawley rats (~P70), followed by behavioral, molecular and electrophysiological assessment 24 h following FSS. Adolescent males, but not adult males or females of either age, demonstrated social anxiety-like behavioral alterations indexed via significantly reduced social investigation and preference when tested 24 h following FSS. Conversely, adult males exhibited increased social preference. While there were no FSS-induced changes in expression of genes related to the DYN/KOP system in the BLA, these behavioral alterations were associated with alterations in BLA KOP function. Specifically, while GABA transmission in BLA pyramidal neurons from non-stressed adolescent males responded variably (potentiated, suppressed, or was unchanged) to the KOP agonist, U69593, U69593 significantly inhibited BLA GABA transmission in the majority of neurons from stressed adolescent males, consistent with the observed anxiogenic phenotype in stressed adolescent males. This is the first study to demonstrate stress-induced alterations in BLA KOP function that may contribute to stress-induced social anxiety in adolescent males. Importantly, these findings provide evidence for potential KOP-dependent mechanisms that may contribute to pathophysiological interactions with subsequent stress challenges.


Assuntos
Ansiedade/psicologia , Complexo Nuclear Basolateral da Amígdala/metabolismo , Receptores Opioides kappa/metabolismo , Estresse Psicológico/psicologia , Natação/psicologia , Envelhecimento/psicologia , Animais , Ansiedade/etiologia , Ansiedade/genética , Dinorfinas/metabolismo , Feminino , Masculino , Técnicas de Patch-Clamp , Células Piramidais/metabolismo , Ratos , Ratos Sprague-Dawley , Receptores Opioides kappa/genética , Caracteres Sexuais , Comportamento Social , Estresse Psicológico/complicações , Estresse Psicológico/genética , Transmissão Sináptica , Ácido gama-Aminobutírico/fisiologia
6.
J Interprof Care ; 32(5): 621-628, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29764248

RESUMO

The World Health Organization has ranked the Middle East (ME) as the second most prevalent region globally for type 2 diabetes. Currently, treatment options initiated by physicians focus mainly on pharmaceuticals; however, lifestyle factors also have a tremendous impact on a patient's wellness or illness. A potential solution to this issue is to use an interprofessional team approach when caring for this patient population. The purpose of this systematic review is to look at the present literature involving the use of an interprofessional team approach to the care and maintenance of people with type 2 diabetes in the ME. A PRISMA flow diagram demonstrates the authors' literature search and screening process. The systematic review includes nine studies with mixed-methodologies performed in the Middle Eastern region in an outpatient or primary care setting, and demonstrates the use of interprofessional collaboration when providing care for type 2 diabetic patients. A meta-analysis was not included due to the heterogeneity of the studies; however, data analysis is discussed and results are demonstrated through an extraction tool developed by the authors based on The Cochrane Collaboration's data collection form. The aim of this review is to construct meaning surrounding the use and effectiveness of this collaborative approach with the adult and geriatric Middle Eastern diabetic patient population. Recommendations include continued support from multiple healthcare professions, involving nurses, pharmacists, dietitians, and physicians to promote holistic and patient-centred-care leading to fewer type 2 diabetes complications and hospital admissions.


Assuntos
Diabetes Mellitus Tipo 2/terapia , Comunicação Interdisciplinar , Relações Interprofissionais , Assistência Centrada no Paciente/organização & administração , Comportamento Cooperativo , Humanos , Oriente Médio , Atenção Primária à Saúde/organização & administração , Garantia da Qualidade dos Cuidados de Saúde
7.
Ann Oncol ; 28(10): 2539-2546, 2017 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-28961851

RESUMO

BACKGROUND: Relapsed/metastatic salivary gland carcinomas (SGCs) have a wide diversity of histologic subtypes associated with variable clinical aggressiveness and response to local and systemic therapies. We queried whether comprehensive genomic profiling could define the tumor subtypes and uncover clinically relevant genomic alterations, revealing new routes to targeted therapies for patients with relapsed and metastatic disease. PATIENTS AND METHODS: From a series of 85 686 clinical cases, DNA was extracted from 40 µm of formalin-fixed paraffin embedded (FFPE) sections for 623 consecutive SGC. CGP was carried out on hybridization-captured, adaptor ligation-based libraries (mean coverage depth, >500×) for up to 315 cancer-related genes. Tumor mutational burden was determined on 1.1 Mb of sequenced DNA. All classes of alterations, base substitutions, short insertions/deletions, copy number changes, and rearrangements/fusions were determined simultaneously. RESULTS: The clinically more indolent SGC including adenoid cystic carcinoma, acinic cell carcinoma, polymorphous low-grade adenocarcinoma, mammary analog secretory carcinoma, and epithelial-myoepithelial carcinomas have significantly fewer genomic alterations, TP53 mutations, and lower tumor mutational burden than the typically more aggressive SGCs including mucoepidermoid carcinoma, salivary duct carcinoma, adenocarcinoma, not otherwise specified, carcinoma NOS, and carcinoma ex pleomorphic adenoma. The more aggressive SGCs are commonly driven by ERBB2 PI3K pathway genomic alterations. Additional targetable GAs are frequently seen. CONCLUSIONS: Genomic profiling of SGCs demonstrates important differences between traditionally indolent and aggressive cancers. These differences may provide therapeutic options in the future.


Assuntos
Carcinoma/genética , Recidiva Local de Neoplasia/genética , Neoplasias das Glândulas Salivares/genética , Idoso , Carcinoma/patologia , DNA de Neoplasias/genética , Feminino , Formaldeído , Perfilação da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Metástase Neoplásica , Recidiva Local de Neoplasia/patologia , Inclusão em Parafina , Neoplasias das Glândulas Salivares/patologia , Fixação de Tecidos
8.
Clin Transl Oncol ; 19(6): 711-717, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27909873

RESUMO

PURPOSE: Many studies recently focus on complicated and expensive genomic tests, but the prognostic values of biochemical markers which are easily obtained in clinics are largely overlooked and without further exploration. This study assesses the association of neutrophil-lymphocyte-ratio (NLR) with prognosis of lung cancer patients. METHODS: In 1032 patients with histologically confirmed lung cancer, the association of pretreatment NLR values with overall survival (OS) was evaluated using a Cox proportional hazards model and the temporal relationship of longitudinal NLR was assessed using a mixed effects model. RESULTS: Compared to the patients with a low pretreatment NLR value, those with elevated NLR exhibited a statistically significant worse OS with a hazard ratio (HR) of 1.50 (P < 0.0001) after adjusting for age, gender, race, smoking status, drinking status, tumor stage, tumor grade, histology, and treatments. A significant trend of increasing HRs along with increasing NLR values was observed. The increased risk of death conferred by pretreatment NLR values reached a peak level around 2 years after diagnosis. Moreover, in longitudinal analysis, we observed a trend of dramatically increased NLR values in patients who died during follow-up, but stable NLR values in those who were still alive, with a significant interaction of death-alive status with follow-up time (P < 0.0001). CONCLUSIONS: Elevated NLR is a potential biomarker to identify lung cancer patients with poor prognosis and should be validated in a future clinical trial.


Assuntos
Neoplasias Pulmonares/sangue , Neoplasias Pulmonares/imunologia , Contagem de Linfócitos , Neutrófilos , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Intervalo Livre de Doença , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Pulmonares/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais
9.
Rev Sci Instrum ; 87(5): 054704, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27250448

RESUMO

In this paper, a solid-state four element array gyromagnetic nonlinear transmission line high power microwave system is presented as well as a detailed description of its subsystems and general output capabilities. This frequency agile S-band source is easily adjusted from 2-4 GHz by way of a DC driven biasing magnetic field and is capable of generating electric fields of 7.8 kV/m at 10 m correlating to 4.2 MW of RF power with pulse repetition frequencies up to 1 kHz. Beam steering of the array at angles of ±16.7° is also demonstrated, and the associated general radiation pattern is detailed.

10.
Rev Sci Instrum ; 86(8): 084702, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26329216

RESUMO

Implementing nonlinear transmission line (NLTL) technology in the design of a high power microwave source has the benefits of producing a comparatively small and lightweight solid-state system where the emission frequency is easily tuned. Usually, smaller in physical size, single NLTLs may produce significantly less power than its vacuum based counterparts. However, combining individual NLTL outputs electrically or in free-space is an attractive solution to achieve greater output power. This paper discusses a method for aligning a four element NLTL antenna array with coaxial geometry using easily adjustable temporal delay lines. These delay lines, sometimes referred to as pulse shock lines or pulse sharpening lines, are placed serially in front of the main NLTL line. The propagation velocity in each delay line is set by the voltage amplitude of an incident pulse as well as the magnetic field bias. Each is adjustable although for the system described in this paper, the voltage is held constant while the bias is changed through applying an external DC magnetic field of varying magnitude. Three different ferrimagnetic materials are placed in the temporal delay line to evaluate which yields the greatest range of electrical delay with the least amount of variability from consecutive shots.

11.
J Anim Sci ; 93(6): 3034-43, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26115289

RESUMO

Two experiments were conducted with 192 steers each (during the winter [November to May] or summer [June to October]) to evaluate 3 diets with or without Yucca schidigera extract in a 3 × 2 factorial on steer growth performance and N mass balance. One factor was diet (DM basis): 1) 5% untreated corn stover, 51% corn, and 40% modified distillers grains plus solubles (MDGS; CON); 2) 20% calcium oxide-treated corn stover (CaO added at 5% of stover DM), 40% MDGS, and 36% corn (TRT); or 3) 20% untreated corn stover, 40% MDGS, and 36% corn (NONTRT). The other factor was dietary extract at 0 (NOYE) or 1.0 g/d per steer (YE). No interaction between diet and YE was detected (P > 0.51) for growth performance and carcass traits in winter and only for DMI in summer. Final BW, ADG, DMI, or G:F were not different (P ≥ 0.28) between cattle fed CON and TRT, whereas cattle fed NONTRT had lesser ADG, HCW, and G:F compared to CON and TRT in the winter experiment. During the summer, final BW and ADG tended to be greater (P ≥ 0.07) for CON compared to TRT. Cattle fed TRT had reduced (P < 0.01) G:F compared to CON. No difference was observed (P ≥ 0.36) between YE and NOYE in the winter experiment for performance or carcass traits. In the summer, cattle fed YE had greater (P < 0.02) HCW, ADG, and DMI compared to NOYE. In the summer experiment, cattle fed YE had greater (P < 0.01) N intake, N excretion, and amount of N lost (kg/steer) compared to NOYE, but no difference (P = 0.33) was observed for percentage of N volatilized (% of excretion). Diet had no effect (P > 0.18) on amount (kg/steer) or percentage of N volatized in the winter or summer. All diets had similar amounts (P > 0.13) of DM and OM removed from the pen surface in both summer and winter. Feeding CaO-treated corn stover as a partial grain replacement had no impact on performance in winter but decreased G:F in summer. Although high-fiber diets increased the amount of OM on pen surfaces, they did not impact N volatilized. Feeding a Y. schidigera extract did not affect N balance or manure characteristics.


Assuntos
Fenômenos Fisiológicos da Nutrição Animal/efeitos dos fármacos , Compostos de Cálcio/farmacologia , Bovinos/fisiologia , Óxidos/farmacologia , Extratos Vegetais/farmacologia , Yucca , Zea mays , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal/fisiologia , Animais , Bovinos/crescimento & desenvolvimento , Dieta/veterinária , Suplementos Nutricionais , Grão Comestível , Masculino , Esterco/análise , Nitrogênio/metabolismo , Estações do Ano
12.
Ultrasound Obstet Gynecol ; 45(1): 84-8, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25380024

RESUMO

OBJECTIVE: Non-invasive fetal Rhesus (Rh) D genotyping, using cell-free fetal DNA (cffDNA) in the maternal blood, allows targeted antenatal anti-RhD prophylaxis in unsensitized RhD-negative pregnant women. The purpose of this study was to determine the cost and benefit of this approach as compared to routine antenatal anti-RhD prophylaxis for all unsensitized RhD-negative pregnant women, as is the current policy in the province of Alberta, Canada. METHODS: This study was a decision analysis based on a theoretical population representing the total number of pregnancies in Alberta over a 1-year period (n = 69 286). A decision tree was created that outlined targeted prophylaxis for unsensitized RhD-negative pregnant women screened for cffDNA (targeted group) vs routine prophylaxis for all unsensitized RhD-negative pregnant women (routine group). Probabilities at each decision point and costs associated with each resource were calculated from local clinical and administrative data. Outcomes measured were cost, number of women sensitized and doses of Rh immunoglobulin (RhIG) administered. RESULTS: The estimated cost per pregnancy for the routine group was 71.43 compared with 67.20 Canadian dollars in the targeted group. The sensitization rates per RhD-negative pregnancy were equal, at 0.0012, for the current and targeted programs. Implementing targeted antenatal anti-RhD prophylaxis would save 4072 doses (20.1%) of RhIG over a 1-year period in Alberta when compared to the current program. CONCLUSIONS: These data support the feasibility of a targeted antenatal anti-RhD prophylaxis program, at a lower cost than that of the existing routine prophylaxis program, with no increased risk of sensitization.


Assuntos
DNA/sangue , Complicações Hematológicas na Gravidez/prevenção & controle , Isoimunização Rh/prevenção & controle , Imunoglobulina rho(D)/uso terapêutico , Adulto , Canadá , Sistema Livre de Células , Análise Custo-Benefício , Feminino , Humanos , Recém-Nascido , Gravidez , Complicações Hematológicas na Gravidez/economia , Avaliação de Programas e Projetos de Saúde , Isoimunização Rh/economia , Sistema do Grupo Sanguíneo Rh-Hr , Imunoglobulina rho(D)/economia
13.
Rev Sci Instrum ; 85(5): 054706, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24880394

RESUMO

Gyromagnetic Nonlinear Transmission Lines (NLTLs) generate microwaves through the damped gyromagnetic precession of the magnetic moments in ferrimagnetic material, and are thus utilized as compact, solid-state, frequency agile, high power microwave (HPM) sources. The output frequency of a NLTL can be adjusted by control of the externally applied bias field and incident voltage pulse without physical alteration to the structure of the device. This property provides a frequency tuning capability not seen in many conventional e-beam based HPM sources. The NLTLs developed and tested are mesoband sources capable of generating MW power levels in the L, S, and C bands of the microwave spectrum. For an individual NLTL the output power at a given frequency is determined by several factors including the intrinsic properties of the ferrimagnetic material and the transmission line structure. Hence, if higher power levels are to be achieved, it is necessary to combine the outputs of multiple NLTLs. This can be accomplished in free space using antennas or in a transmission line via a power combiner. Using a bias-field controlled delay, a transient, high voltage, coaxial, three port, power combiner was designed and tested. Experimental results are compared with the results of a transient COMSOL simulation to evaluate combiner performance.

14.
J Environ Qual ; 42(4): 1274-80, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24216379

RESUMO

Difficulties in accessing high-quality data on trace gas fluxes and performance of bioenergy/bioproduct feedstocks limit the ability of researchers and others to address environmental impacts of agriculture and the potential to produce feedstocks. To address those needs, the GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement network) and REAP (Renewable Energy Assessment Project) research programs were initiated by the USDA Agricultural Research Service (ARS). A major product of these programs is the creation of a database with greenhouse gas fluxes, soil carbon stocks, biomass yield, nutrient, and energy characteristics, and input data for modeling cropped and grazed systems. The data include site descriptors (e.g., weather, soil class, spatial attributes), experimental design (e.g., factors manipulated, measurements performed, plot layouts), management information (e.g., planting and harvesting schedules, fertilizer types and amounts, biomass harvested, grazing intensity), and measurements (e.g., soil C and N stocks, plant biomass amount and chemical composition). To promote standardization of data and ensure that experiments were fully described, sampling protocols and a spreadsheet-based data-entry template were developed. Data were first uploaded to a temporary database for checking and then were uploaded to the central database. A Web-accessible application allows for registered users to query and download data including measurement protocols. Separate portals have been provided for each project (GRACEnet and REAP) at nrrc.ars.usda.gov/slgracenet/#/Home and nrrc.ars.usda.gov/slreap/#/Home. The database architecture and data entry template have proven flexible and robust for describing a wide range of field experiments and thus appear suitable for other natural resource research projects.


Assuntos
Efeito Estufa , Solo , Agricultura , Carbono , Produtos Agrícolas , Fertilizantes , Solo/química
15.
J Anim Sci ; 91(12): 5878-84, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24126272

RESUMO

A 2-yr pen experiment was conducted using 12 different crossbred Angus steers each year to determine if short-term changes in prolactin concentrations, body temperature, and vasoconstriction reflect recovery from fescue toxicosis after steers that previously grazed toxic endophyte (Neotyphodium coenophialum)-infected Kentucky 31 tall fescue [Lolium arundinaceum (Schreb.) Darbysh] are placed on nontoxic feed. Groups of 6 steers from toxic endophyte-infected and endophyte-free tall fescue grazing treatments were blocked by BW for assignment to pens as a randomized complete block design with 2 replications. Two environments were implemented by initiating the experiment on 18 August in yr 1 and on 8 September in yr 2 for durations of 30 and 21 d, respectively. Rectal temperatures were recorded, jugular blood was collected for assaying serum prolactin, and cross sections of the caudal artery were ultrasonically imaged at selected time points to evaluate temporal changes in the response variables. Rectal temperatures in steers on the toxic endophyte pasture treatment declined (P < 0.05) linearly over time in yr 1 and 2 and were similar (P > 0.10) to those on endophyte-free treatment on d 30 in yr 1 and by d 15 in yr 2. Prolactin concentrations in steers on the toxic endophyte pasture treatment showed curvilinear increases (P < 0.05) over time and were similar (P > 0.10) to steers on the endophyte-free treatment by d 15 in yr 1 and by d 10 in yr 2. Luminal areas of the caudal artery in toxic endophyte steers were less (P < 0.05) than those in endophyte-free steers across all dates in both years. Results indicated that rectal temperatures in steers after they are removed from toxic fescue may decrease over time, but temporal changes in rectal temperatures could be affected more by prevailing ambient temperatures than by actual mitigation of fescue toxicosis. Prolactin concentrations in steers after they are removed from toxic endophyte tall fescue can increase and stabilize in less than 2 wk, but alkaloid-induced vasoconstriction that causes a vulnerability to severe heat stress is not alleviated within 30 d.


Assuntos
Ração Animal/efeitos adversos , Criação de Animais Domésticos/métodos , Doenças dos Bovinos/induzido quimicamente , Lolium/microbiologia , Neotyphodium/fisiologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Temperatura Corporal , Bovinos , Dieta/veterinária , Masculino , Micoses , Prolactina
16.
J Anim Sci ; 91(9): 4492-500, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23825335

RESUMO

Pharmacologic profiling of serotonin (5HT) receptors of bovine lateral saphenous vein has shown that cattle grazing endophyte-infected (Neotyphodium coenophialum) tall fescue (Lolium arundinaceum) have altered responses to ergovaline, 5HT, 5HT2A, and 5HT7 agonists. To determine if 5HT receptor activity of tall fescue alkaloids is affected by grazing endophyte-free (EF), wild-type [Kentucky-31 (KY31)], novel endophyte AR542-infected (MAXQ), or novel endophyte AR584-infected (AR584) tall fescue, contractile responses of lateral saphenous veins biopsied from cattle grazing these different fescue-endophyte combinations were evaluated in presence or absence of antagonists for 5HT2A (ketanserin) or 5HT7 (SB-269970) receptors. Biopsies were conducted over 2 yr on 35 mixed-breed steers (361.5 ± 6.3 kg) grazing EF (n = 12), KY31 (n = 12), MAXQ (n = 6), or AR584 (n = 5) pasture treatments (3 ha) between 84 and 98 d (Yr 1) or 108 to 124 d (Yr 2). Segments (2 to 3 cm) of vein were surgically biopsied, sliced into 2- to 3-mm cross-sections, and suspended in a myograph chamber containing 5 mL of oxygenated Krebs-Henseleit buffer (95% O2/5% CO2; pH = 7.4; 37°C). Veins were exposed to increasing concentrations of 5HT, ergovaline, and ergovaline + 1 × 10(-5) M ketanserin or + 1 × 10(-6) M SB-269970 in Yr 1. In Yr 2, ergotamine and ergocornine were evaluated in presence or absence of 1 × 10(-5) M ketanserin. Contractile response data were normalized to a reference addition of 1 × 10(-4) M norepinephrine. In Yr 1, contractile response to 5HT and ergovaline were least (P < 0.05) in KY31 pastures and the presence of ketanserin greatly reduced (P < 0.05) the response to ergovaline in all pastures. However, presence of SB-269970 did not (P = 0.91) alter contractile response to ergovaline. In Yr 2, there was no difference in contractile response to ergotamine (P = 0.13) or ergocornine (P = 0.99) across pasture treatments, but ketanserin reduced (P < 0.05) the contractile response to both alkaloids. The 5HT2A receptor is involved in alkaloid-induced vascular contraction and alkaloid binding may be affected by exposure to different endophyte-fescue combinations.


Assuntos
Bovinos/metabolismo , Endófitos/fisiologia , Alcaloides de Claviceps/toxicidade , Festuca/microbiologia , Lolium/microbiologia , Neotyphodium/fisiologia , Veia Safena/metabolismo , Antagonistas da Serotonina/farmacologia , Ração Animal/análise , Animais , Dieta/veterinária , Endófitos/química , Ergolinas/toxicidade , Ergotamina/toxicidade , Ergotaminas/toxicidade , Masculino , Neotyphodium/química , Distribuição Aleatória , Antagonistas do Receptor 5-HT2 de Serotonina/farmacologia
17.
AJNR Am J Neuroradiol ; 34(8): 1626-31, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23471025

RESUMO

BACKGROUND AND PURPOSE: To date, no systematic evaluation of image quality has been performed on the 256-section multidetector CT scanner for extracranial carotid evaluations. We evaluated image quality, patient dose, and examination time and compared these parameters with a 64-section multidetector CT. MATERIALS AND METHODS: We reviewed extracranial CTA scans obtained on a 256-detector CT scanner in 50 consecutive patients. Image quality was analyzed for artifacts and vessel contrast opacification from the aortic arch to the skull base, dose to patient, and scan time. Results were compared with a control group of 50 patients imaged on a 64-section CT scanner. A Fisher exact test was used to analyze both groups with respect to vessel contrast opacification and presence of artifacts, and a Student t test was used to assess differences in patient dose between the 2 groups. RESULTS: Quantitative and qualitative evaluations revealed >95% acceptable vessel opacification at all levels measured on the 256-section scanner. Scan time was improved (4 seconds on 256-channel). There were fewer artifacts related to metallic streak on the 256-channel CTA study, and DLP was lower on the 256-channel CTA (113.9 versus 159.8 mGy). CONCLUSIONS: The 256-channel CTA imaging protocol for carotid arteries yielded similar vessel contrast opacification compared with the 64-channel CTA but with fewer metallic artifacts, a modest decrease in scan time, similar image quality, and a statistically significant reduction in radiation dose of 10%.


Assuntos
Doenças das Artérias Carótidas/diagnóstico por imagem , Angiografia Cerebral/métodos , Tomografia Computadorizada Multidetectores/métodos , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Artérias Carótidas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
18.
J Anim Sci ; 90(7): 2402-9, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22287669

RESUMO

A 2-yr grazing experiment was conducted with crossbred steers (8 to 10 mo and with initial BW of 304 kg ± 34 kg in 2008 and 277 kg ± 24 in 2009) to evaluate animal performance and pasture responses of a late maturing tall fescue [Lolium arundinaceum (Schreb.) Darbysh; KYFA9301] population infected with the AR584 novel, non-toxic endophyte (Neotyphodium coenophialum; NE9301) as compared with Kentucky 31 fescue infected with the common toxic endophyte strain (KY31), 'Jesup' MaxQ fescue infected with the AR542 endophyte (MaxQ), and endophyte-free KYFA9301 (EF9301). Treatments were assigned for seeding in 1.0-ha pastures in a randomized complete block design with 3 replications. Pastures were grazed from 6 May to 23 July in 2008 (76 d) and 2 April to 25 June in 2009 (84 d). Each pasture was grazed with 4 tester steers and put-and-take steers were used to maintain forage mass at 2,500 ± 250 kg DM/ha. Shrunk BW was taken at initiation and termination of grazing each year. Rectal and skin temperatures were recorded, and jugular blood was collected each year at approximately d 28, 56, and study completion. Forage samples were collected at 2-wk intervals for analyzing CP, IVDMD, ADF, and NDF. Responses were analyzed with mixed models, and preplanned orthogonal contrasts were used to compare KY31 with non-toxic fescues, EF9301 vs. novel endophyte fescues, and NE9301 vs. MaxQ. All steer responses were similar (P > 0.10) among the non-toxic fescues. Average daily gains and total BW gain/ha for the 3 non-toxic fescues were greater (P < 0.001) than for KY31. Rectal/skin temperatures for the 3 non-toxic fescues were less (P < 0.001) and serum prolactin concentrations were greater (P < 0.01) than for KY-31. Pasture carrying capacity was greater (P = 0.003) for KY31 than the 3 non-toxic fescues and was greater for EF9301 (P = 0.017) than the 2 novel endophyte fescues. However, stocking rates (kg BW/ha) at the initial and midpoint days of grazing were similar (P > 0.40) among endophyte-fescue combinations, but by the end of the grazing season, stocking rate was greater (P < 0.001) for KY31 than for the non-toxic fescues and was greater (P = 0.053) for NE9301 than for MaxQ. Results indicated that NE9301 is as effective as EF9301 and MaxQ in improving BW gain and alleviating fescue toxicosis and that NE9301 can provide greater carrying capacities than MaxQ in late June and July.


Assuntos
Bovinos/fisiologia , Lolium/fisiologia , Neotyphodium/fisiologia , Agricultura , Ração Animal/efeitos adversos , Criação de Animais Domésticos/economia , Animais , Masculino , Chuva , Fatores de Tempo
19.
J Pediatric Infect Dis Soc ; 1(1): 47-54, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26618693

RESUMO

BACKGROUND: The California Department of Public Health (CDPH) declared a pertussis epidemic on 23 June 2010. More cases were reported in 2010 (9146) than in any year since 1947. We describe the characteristics of pertussis epidemiology and disease from 986 reported cases in children in San Diego County (population 3.2 million). METHODS: Descriptive statistics were abstracted from CDPH pertussis case report forms that were completed by public health nurses investigating reports of positive laboratory results for pertussis and reports of illnesses compatible with pertussis. RESULTS: Of 1144 reported adult and pediatric cases, 753 (66%) were confirmed and 391 were probable/suspect. Children aged <19 years comprised 86% of all reported cases in San Diego County; of these, 22% were aged 11-18 years, 29% were aged 6-10 years, 27% were aged 1-5 years, and 22% were aged <1 year (with 70% aged <6 months). Case rates were highest in infants aged <6 months (651 per 100 000 population). Of those aged >1 year, the highest attack rates were in preschool children aged 1-5 years (114 per 100 000) and elementary school children aged 6-10 years (141 per 100 000). Of 51 children hospitalized, 82% were aged <6 months; 2 deaths occurred in these young infants. Paroxysmal cough was noted in over 70% of children in all age groups; post-tussive vomiting occurred in 36% (aged 11-18 years) to 57% (aged <6 months) of children. CONCLUSIONS: Pertussis vaccine efficacy may decrease more rapidly than previously believed, facilitating spread of pertussis in elementary school-aged children. The highest case rates and the only mortality occurred in infants aged <6 months.

20.
Int J Impot Res ; 23(2): 43-8, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21289638

RESUMO

Aging is associated with ED. Although age-related ED is attributed largely to increased oxidative stress and endothelial dysfunction in the penis, the molecular mechanisms underlying this effect are not fully defined. We evaluated whether endothelial nitric oxide synthase (eNOS) uncoupling in the aged rat penis is a contributing mechanism. Correlatively, we evaluated the effect of replacement with eNOS cofactor tetrahydrobiopterin (BH(4)) on erectile function in the aged rats. Male Fischer 344 'young' (4-month-old) and 'aged' (19-month-old) rats were treated with a BH(4) precursor sepiapterin (10 mg/kg intraperitoneally) or vehicle for 4 days. After 1-day washout, erectile function was assessed in response to electrical stimulation of the cavernous nerve. Endothelial dysfunction (eNOS uncoupling) and oxidative stress (thiobarbituric acid reactive substances, TBARS) were measured by conducting western blot in penes samples. Erectile response was significantly reduced in aged rats, whereas eNOS uncoupling and TBARS production were significantly increased in the aged rat penis compared with young rats. Sepiapterin significantly improved erectile response in aged rats and prevented increase in TBARS production, but did not affect eNOS uncoupling in the penis of aged rats. These findings suggest that aging induces eNOS uncoupling in the penis, resulting in increased oxidative stress and ED.


Assuntos
Disfunção Erétil/enzimologia , Óxido Nítrico Sintase Tipo III/metabolismo , Estresse Oxidativo , Pterinas/uso terapêutico , Envelhecimento/metabolismo , Animais , Disfunção Erétil/tratamento farmacológico , Masculino , Ereção Peniana/efeitos dos fármacos , Pênis/efeitos dos fármacos , Pênis/metabolismo , Pterinas/farmacologia , Ratos , Ratos Endogâmicos F344 , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA