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1.
Sci Total Environ ; 765: 142768, 2021 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-33097260

RESUMEN

Transport of nutrients to lakes can occur via surface-water inflow, atmospheric deposition, groundwater (GW) inflow and benthic processes. Identifying and quantifying within-lake nutrient sources and recycling processes is challenging. Prior studies in hypereutrophic Upper Klamath Lake, Oregon, USA, indicated that ~60% of the early summer phosphorus (P) load to the lake was internal and hypothesized to be lakebed sediment release. Dynamic nutrient transport processes were examined to better characterize the nutrient sources. One-dimensional heat transport models calibrated to observed lakebed temperatures and a cross-sectional GW flow model provided estimates of GW-inflow rates that were greatest in spring and decreased through summer. One-dimensional solute transport models calibrated to observed lakebed pore-water dissolved silica (Si) and dissolved phosphate-phosphorus (DP) concentrations indicated that nutrients were transported from the lakebed by advection, diffusion, and enhanced mixing by benthic organisms and waves, and that DP removal occurred near the lakebed interface. Estimated water, Si, DP and total-phosphorus (TP) budgets indicated that GW contributed 21% of lake water inflow and at least 26, 20 and 16% of total Si, DP and TP inflow, respectively, when conservatively assuming background GW nutrient concentrations. However, lakebed GW (LGW) is enriched in nutrients during flow through lakebed sediment and the estimated GW contribution increased to 29 (33), 49 (67) and 43% (61%) of total Si, DP and TP inflow, respectively, if 20% (50%) of GW inflow to the lake was assumed to have LGW concentrations. Net nutrient inflow to the lake was greatest in spring and coincident with the annual diatom bloom. Inflowing dissolved nutrients appear to be assimilated by diatoms during the spring and become available for the summer Aphanizomenon flos-aquae bloom when the diatoms senesce. Thus, nutrient-enriched GW inflow and nutrient recycling by successive algal blooms must be considered when evaluating internal nutrient loading to lakes.


Asunto(s)
Agua Subterránea , Lagos , Aphanizomenon , China , Estudios Transversales , Monitoreo del Ambiente , Eutrofización , Nitrógeno/análisis , Nutrientes , Oregon , Fósforo/análisis
2.
J Agric Food Chem ; 68(39): 10852-10864, 2020 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-32893631

RESUMEN

An international project developed, quality-tested, and measured isotope-delta values of 10 new food matrix reference materials (RMs) for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements to support food authenticity testing and food provenance verification. These new RMs, USGS82 to USGS91, will enable users to normalize measurements of samples to isotope-delta scales. The RMs include (i) two honeys from Canada and tropical Vietnam, (ii) two flours from C3 (rice) and C4 (millet) plants, (iii) four vegetable oils from C3 (olive, peanut) and C4 (corn) plants, and (iv) two collagen powders from marine fish and terrestrial mammal origins. An errors-in-variables regression model included the uncertainty associated with the measured and assigned values of the RMs, and it was applied centrally to normalize results and obtain consensus values and measurement uncertainties. Utilization of these new RMs should facilitate mutual compatibility of stable isotope data if accepted normalization procedures are applied and documented.


Asunto(s)
Colágeno/análisis , Deuterio/análisis , Harina/análisis , Miel/análisis , Isótopos de Nitrógeno/análisis , Isótopos de Oxígeno/análisis , Aceites de Plantas/química , Isótopos de Azufre/análisis , Animales , Proteínas de Peces/análisis , Peces
3.
Nutrients ; 12(9)2020 Aug 25.
Artículo en Inglés | MEDLINE | ID: mdl-32854375

RESUMEN

BACKGROUND: Disturbed sleep may negatively influence physical health, cognitive performance, metabolism, and general wellbeing. Nutritional interventions represent a potential non-pharmacological means to increase sleep quality and quantity. OBJECTIVE: (1) Identify an optimal suite of nutritional ingredients and (2) validate the effects of this suite utilising polysomnography, and cognitive and balance tests. METHODS: The optimal and least optimal combinations of six ingredients were identified utilising 55 male participants and a Box-Behnken predictive model. To validate the model, 18 healthy, male, normal sleepers underwent three trials in a randomised, counterbalanced design: (1) optimal drink, (2) least optimal drink, or (3) placebo were provided before bed in a double-blinded manner. Polysomnography was utilised to measure sleep architecture. Cognitive performance, postural sway, and subjective sleep quality, were assessed 30 min after waking. RESULTS: The optimal drink resulted in a significantly shorter sleep onset latency (9.9 ± 12.3 min) when compared to both the least optimal drink (26.1 ± 37.4 min) and the placebo drink (19.6 ± 32.0 min). No other measures of sleep, cognitive performance, postural sway, and subjective sleep quality were different between trials. CONCLUSION: A combination of ingredients, optimised to enhance sleep, significantly reduced sleep onset latency. No detrimental effects on sleep architecture, subjective sleep quality or next day performance were observed.


Asunto(s)
Suplementos Dietéticos , Sueño , Adenosina Monofosfato/administración & dosificación , Adulto , Método Doble Ciego , Jugos de Frutas y Vegetales , Glutamatos/administración & dosificación , Humanos , Lactalbúmina/administración & dosificación , Masculino , Polisomnografía , Prunus avium , Triptófano/sangre , Valeriana
4.
Sports Med ; 47(11): 2201-2218, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28702900

RESUMEN

Team sport athletes face a variety of nutritional challenges related to recovery during the competitive season. The purpose of this article is to review nutrition strategies related to muscle regeneration, glycogen restoration, fatigue, physical and immune health, and preparation for subsequent training bouts and competitions. Given the limited opportunities to recover between training bouts and games throughout the competitive season, athletes must be deliberate in their recovery strategy. Foundational components of recovery related to protein, carbohydrates, and fluid have been extensively reviewed and accepted. Micronutrients and supplements that may be efficacious for promoting recovery include vitamin D, omega-3 polyunsaturated fatty acids, creatine, collagen/vitamin C, and antioxidants. Curcumin and bromelain may also provide a recovery benefit during the competitive season but future research is warranted prior to incorporating supplemental dosages into the athlete's diet. Air travel poses nutritional challenges related to nutrient timing and quality. Incorporating strategies to consume efficacious micronutrients and ingredients is necessary to support athlete recovery in season.


Asunto(s)
Atletas , Carbohidratos de la Dieta/administración & dosificación , Suplementos Dietéticos , Metabolismo Energético/fisiología , Glucógeno/metabolismo , Músculo Esquelético/metabolismo , Enfermedades Musculares/dietoterapia , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/metabolismo , Proteínas en la Dieta/metabolismo , Humanos , Fatiga Muscular/fisiología , Fenómenos Fisiológicos de la Nutrición , Necesidades Nutricionales , Estaciones del Año , Deportes
5.
J Appl Physiol (1985) ; 122(3): 642-652, 2017 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-27909231

RESUMEN

We hypothesized that 4 wk of dietary nitrate supplementation would enhance exercise performance and muscle metabolic adaptations to sprint interval training (SIT). Thirty-six recreationally active subjects, matched on key variables at baseline, completed a series of exercise tests before and following a 4-wk period in which they were allocated to one of the following groups: 1) SIT and [Formula: see text]-depleted beetroot juice as a placebo (SIT+PL); 2) SIT and [Formula: see text]-rich beetroot juice (~13 mmol [Formula: see text]/day; SIT+BR); or 3) no training and [Formula: see text]-rich beetroot juice (NT+BR). During moderate-intensity exercise, pulmonary oxygen uptake was reduced by 4% following 4 wk of SIT+BR and NT+BR (P < 0.05) but not SIT+PL. The peak work rate attained during incremental exercise increased more in SIT+BR than in SIT+PL (P < 0.05) or NT+BR (P < 0.001). The reduction in muscle and blood [lactate] and the increase in muscle pH from preintervention to postintervention were greater at 3 min of severe-intensity exercise in SIT+BR compared with SIT+PL and NT+BR (P < 0.05). However, the change in severe-intensity exercise performance was not different between SIT+BR and SIT+PL (P > 0.05). The relative proportion of type IIx muscle fibers in the vastus lateralis muscle was reduced in SIT+BR only (P < 0.05). These findings suggest that BR supplementation may enhance some aspects of the physiological adaptations to SIT.NEW & NOTEWORTHY We investigated the influence of nitrate-rich and nitrate-depleted beetroot juice on the muscle metabolic and physiological adaptations to 4 wk of sprint interval training. Compared with placebo, dietary nitrate supplementation reduced the O2 cost of submaximal exercise, resulted in greater improvement in incremental (but not severe-intensity) exercise performance, and augmented some muscle metabolic adaptations to training. Nitrate supplementation may facilitate some of the physiological responses to sprint interval training.


Asunto(s)
Adaptación Fisiológica/fisiología , Suplementos Dietéticos , Entrenamiento de Intervalos de Alta Intensidad/métodos , Músculo Esquelético/fisiología , Nitratos/administración & dosificación , Consumo de Oxígeno/fisiología , Carrera/fisiología , Adaptación Fisiológica/efectos de los fármacos , Administración Oral , Adulto , Rendimiento Atlético/fisiología , Humanos , Masculino , Músculo Esquelético/efectos de los fármacos , Oxígeno/metabolismo , Consumo de Oxígeno/efectos de los fármacos , Análisis y Desempeño de Tareas
6.
Nitric Oxide ; 61: 55-61, 2016 12 30.
Artículo en Inglés | MEDLINE | ID: mdl-27777094

RESUMEN

The influence of dietary nitrate (NO3-) supplementation on indices of maximal sprint and intermittent exercise performance is unclear. PURPOSE: To investigate the effects of NO3- supplementation on sprint running performance, and cognitive function and exercise performance during the sport-specific Yo-Yo Intermittent Recovery level 1 test (IR1). METHODS: In a double-blind, randomized, crossover study, 36 male team-sport players received NO3--rich (BR; 70 mL·day-1; 6.4 mmol of NO3-), and NO3--depleted (PL; 70 mL·day-1; 0.04 mmol NO3-) beetroot juice for 5 days. On day 5 of supplementation, subjects completed a series of maximal 20-m sprints followed by the Yo-Yo IR1. Cognitive tasks were completed prior to, during and immediately following the Yo-Yo IR1. RESULTS: BR improved sprint split times relative to PL at 20 m (1.2%; BR 3.98 ± 0.18 vs. PL 4.03 ± 0.19 s; P < 0.05), 10 m (1.6%; BR 2.53 ± 0.12 vs. PL 2.57 ± 0.19 s; P < 0.05) and 5 m (2.3%; BR 1.73 ± 0.09 vs. PL 1.77 ± 0.09 s; P < 0.05). The distance covered in the Yo-Yo IR1 test improved by 3.9% (BR 1422 ± 502 vs. PL 1369 ± 505 m; P < 0.05). The reaction time to the cognitive tasks was shorter in BR (615 ± 98 ms) than PL (645 ± 120 ms; P < 0.05) at rest but not during the Yo-Yo IR1. There was no difference in response accuracy. CONCLUSIONS: Dietary NO3- supplementation enhances maximal sprint and high-intensity intermittent running performance in competitive team sport players. Our findings suggest that NO3- supplementation has the potential to improve performance in single-sprint or multiple-sprint (team) sports.


Asunto(s)
Rendimiento Atlético/fisiología , Nitratos , Carrera/fisiología , Adulto , Beta vulgaris , Presión Sanguínea/efectos de los fármacos , Estudios Cruzados , Suplementos Dietéticos , Método Doble Ciego , Jugos de Frutas y Vegetales , Humanos , Masculino , Nitratos/administración & dosificación , Nitratos/farmacología , Nitritos/sangre , Test de Stroop , Adulto Joven
7.
Eur J Appl Physiol ; 116(5): 867-77, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26908041

RESUMEN

PURPOSE: To determine effects of intensified training (IT) and carbohydrate supplementation on overreaching and immunity. METHODS: In a randomized, double-blind, crossover design, 13 male cyclists (age 25 ± 6 years, VO2max 72 ± 5 ml/kg/min) completed two 8-day periods of IT. On one occasion, participants ingested 2 % carbohydrate (L-CHO) beverages before, during and after training sessions. On the second occasion, 6 % carbohydrate (H-CHO) solutions were ingested before, during and after training, with the addition of 20 g of protein in the post-exercise beverage. Blood samples were collected before and immediately after incremental exercise to fatigue on days 1 and 9. RESULTS: In both trials, IT resulted in decreased peak power (375 ± 37 vs. 391 ± 37 W, P < 0.001), maximal heart rate (179 ± 8 vs. 190 ± 10 bpm, P < 0.001) and haematocrit (39 ± 2 vs. 42 ± 2 %, P < 0.001), and increased plasma volume (P < 0.001). Resting plasma cortisol increased while plasma ACTH decreased following IT (P < 0.05), with no between-trial differences. Following IT, antigen-stimulated whole blood culture production of IL-1α was higher in L-CHO than H-CHO (0.70 (95 % CI 0.52-0.95) pg/ml versus 0.33 (0.24-0.45) pg/ml, P < 0.01), as was production of IL-1ß (9.3 (95 % CI 7-10.4) pg/ml versus 6.0 (5.0-7.8) pg/ml, P < 0.05). Circulating total leukocytes (P < 0.05) and neutrophils (P < 0.01) at rest increased following IT, as did neutrophil:lymphocyte ratio and percentage CD4+ lymphocytes (P < 0.05), with no between-trial differences. CONCLUSION: IT resulted in symptoms consistent with overreaching, although immunological changes were modest. Higher carbohydrate intake was not able to alleviate physiological/immunological disturbances.


Asunto(s)
Ciclismo/fisiología , Biomarcadores/sangre , Carbohidratos de la Dieta/inmunología , Ejercicio Físico/fisiología , Resistencia Física/inmunología , Resistencia Física/fisiología , Hormona Adrenocorticotrópica/sangre , Adulto , Linfocitos T CD4-Positivos/inmunología , Estudios Cruzados , Suplementos Dietéticos , Método Doble Ciego , Fatiga/sangre , Fatiga/inmunología , Humanos , Hidrocortisona/sangre , Interleucina-1alfa/sangre , Interleucina-1beta/sangre , Masculino
8.
Mol Biotechnol ; 44(2): 90-100, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19898971

RESUMEN

Onset of juvenile Type 1 diabetes (T1D) occurs when autoreactive lymphocytes progressively destroy the insulin-producing beta-cells in the pancreatic Islets of Langerhans. The increasing lack of insulin and subsequent onset of hyperglycemia results in increased damage to nerves, blood vessels, and tissues leading to the development of a host of severe disease symptoms resulting in premature morbidity and mortality. To enhance restoration of normoglycemia and immunological homeostasis generated by lymphocytes that mediate the suppression of autoimmunity, the non-toxic B chain of the plant AB enterotoxin ricin (RTB), a castor bean lectin binding a variety of epidermal cell receptors, was genetically linked to the coding region of the proinsulin gene (INS) and expressed as a fusion protein (INS-RTB) in transformed potato plants. This study is the first documented example of a plant enterotoxin B subunit linked to an autoantigen and expressed in transgenic plants for enhanced immunological suppression of T1D autoimmunity.


Asunto(s)
Plantas Modificadas Genéticamente/metabolismo , Proinsulina/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Ricina/metabolismo , Solanum tuberosum/metabolismo , Ensayo de Inmunoadsorción Enzimática , Vectores Genéticos , Humanos , Immunoblotting , Plantas Modificadas Genéticamente/genética , Reacción en Cadena de la Polimerasa , Proinsulina/genética , Proteínas Recombinantes de Fusión/genética , Ricina/genética , Solanum tuberosum/genética
9.
J Natl Med Assoc ; 94(5): 371-5, 2002 May.
Artículo en Inglés | MEDLINE | ID: mdl-12069218

RESUMEN

There is an astonishing diversity of religious beliefs and practices in the history of African Americans that influences the presentation, diagnosis, and management of both physical and mental disorders. The majority of African Americans, however, are evangelical Christians with religious experiences originating in the regions of ancient Africa (Cush, Punt, and to a great extent, Egypt), as well as black adaptation of Hebraic, Jewish, Christian, and Islamic beliefs and rituals. Consequently, more than 60 of the nation's 125 medical schools offer classes in spirituality and health. Although there is a lack of empirical evidence that religion improves health outcomes, physicians should understand patients as a biopsychosocial-spiritual whole. Asking about religion/spirituality during a health assessment can help the physician determine whether religious/spiritual factors will influence the patient's medical decisions and compliance. Two psychiatric case histories of African Americans are presented in which religion/spirituality significantly influenced treatment decisions and results. Neither of these patients suffered major debilitating medical comorbidity.


Asunto(s)
Negro o Afroamericano/estadística & datos numéricos , Trastornos Mentales/etnología , Trastornos Mentales/terapia , Religión y Psicología , Espiritualidad , Adulto , Características Culturales , Atención a la Salud/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estados Unidos
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