Continuous, Real-Time Monitoring of Cocaine in Undiluted Blood Serum via a Microfluidic, Electrochemical Aptamer-Based Sensor

The development of a biosensor system capable of continuous, real-time measurement of small-molecule analytes directly in complex, unprocessed aqueous samples has been a significant challenge, and successful implementation has been achieved for only a limited number of targets. Towards a general solution to this problem, we report here the Microfluidic Electrochemical Aptamer-based Sensor (MECAS) chip wherein we integrate target-specific DNA aptamers that fold, and thus generate an electrochemical signal, in response to the analyte with a microfluidic detection system. As a model, we demonstrate the continuous, real-time (~1 minute time resolution) detection of the small molecule drug cocaine at near physiological, low micromolar concentrations directly in undiluted, otherwise unmodified blood serum. We believe our approach of integrating folding-based electrochemical sensors with miniaturized detection systems may lay the ground work for the realtime, point-of-care detection of a wide variety of molecular targets

Continuous, Real-Time Monitoring of Cocaine in Undiluted Blood Serum via a Microfluidic, Electrochemical Aptamer-Based Sensor

The development of a biosensor system capable of continuous, real-time measurement of small-molecule analytes directly in complex, unprocessed aqueous samples has been a significant challenge, and successful implementation has been achieved for only a limited number of targets. Towards a general solution to this problem, we report here the Microfluidic Electrochemical Aptamer-based Sensor (MECAS) chip wherein we integrate target-specific DNA aptamers that fold, and thus generate an electrochemical signal, in response to the analyte with a microfluidic detection system. As a model, we demonstrate the continuous, real-time (~1 minute time resolution) detection of the small molecule drug cocaine at near physiological, low micromolar concentrations directly in undiluted, otherwise unmodified blood serum. We believe our approach of integrating folding-based electrochemical sensors with miniaturized detection systems may lay the ground work for the realtime, point-of-care detection of a wide variety of molecular targets

Effect of cycling position on oxygen uptake and preferred cadence in trained cyclists during hill climbing at various power outputs

Numerous researchers have studied the physiological responses to seated and standing cycling, but actual field data are sparse. One open issue is the preferred cadence of trained cyclists while hill climbing. The purpose of this study, therefore, was to examine the affect of cycling position on economy and preferred cadence in trained cyclists while they climbed a moderate grade hill at various power outputs. Eight trained cyclists (25.8 ± 7.2 years, V̇O 68.8 ± 5.0 ml kg min , peak power 407.6 ± 69.0 W) completed a seated and standing hill climb at approximately 50, 65 and 75% of peak power output (PPO) in the order shown, although cycling position was randomized, i.e., half the cyclists stood or remained seat on their first trial at each power output. Cyclists also performed a maximal trial unrestricted by position. Heart rate, power output, and cadence were measured continuously with a power tap; ventilation V̇e, BF and cadence were significantly higher with seated climbing at all intensities; there were no other physiological differences between the climbing positions. These data support the premise that trained cyclists are equally economical using high or low cadences, but may face a limit to benefits gained with increasing cadence. © Springer-Verlag 2006. 2max -1 -

T (2007) Effect of cycling position on oxygen uptake and preferred cadence in trained cyclists during hill climbing at various power outputs

Abstract Numerous researchers have studied the physiological responses to seated and standing cycling, but actual field data are sparse. One open issue is the preferred cadence of trained cyclists while hill climbing. The purpose of this study, therefore, was to examine the affect of cycling position on economy and preferred cadence in trained cyclists while they climbed a moderate grade hill at various power outputs. Eight trained cyclists (25.8 ± 7.2 years, _ VO 2 max 68.8 ± 5.0 ml kg -1 min -1 , peak power 407.6 ± 69.0 W) completed a seated and standing hill climb at approximately 50, 65 and 75% of peak power output (PPO) in the order shown, although cycling position was randomized, i.e., half the cyclists stood or remained seat on their first trial at each power output. Cyclists also performed a maximal trial unrestricted by position. Heart rate, power output, and cadence were measured continuously with a power tap; ventilation _ Ve, BF and cadence were significantly higher with seated climbing at all intensities; there were no other physiological differences between the climbing positions. These data support the premise that trained cyclists are equally economical using high or low cadences, but may face a limit to benefits gained with increasing cadence

The Effect of Betaine on Nitrate and Cardiovascular Response to Exercise

International Journal of Exercise Science 10(4): 550-559, 2017. Betaine (BT) supplementation improves selected markers of physical performance, however, the mechanism(s) by which this change occurs remains largely unknown. Some speculate that BT may increase circulating nitrate concentrations, improving physical performance by augmentation of endothelial nitric oxide production. The purpose of this study was to investigate the effects of acute BT supplementation and exercise on plasma nitrate levels and related cardiovascular response (CVR). Placebo and BT trials were administered in a cross-over, randomized, double-blind, and counterbalanced fashion. Ten healthy college-aged volunteers consumed either a 250 ml placebo (carbohydrate-electrolyte beverage, CHO) or 250 ml CHO + 2.5 g BT. Subjects rested for 45 min, then cycled for 30 min at 60 rpm with a resistance of 2.5% body weight. Blood was drawn before and 45 min after BT supplementation, and immediately post exercise to assess plasma nitrate levels. Repeated measures ANOVA across treatments and times assessed differences in plasma nitrate and CVR variables with an alpha level set at 0.05. No significant interactions nor differences between groups were found for plasma nitrate levels or CVR variables with acute BT supplementation. A significant time effect (p \u3c 0.013) for all CVR variables was found and expected due to the effect of exercise. Acute BT supplementation did not increase plasma nitrate levels nor alter CVR at rest or during light to moderate cycling

Bone Resorption in Syndromes of the Ras/MAPK Pathway

BACKGROUND: Disorders of the Ras/MAPK pathway have an overlapping skeletal phenotype (eg. scoliosis, osteopenia). The Ras proteins regulate cell proliferation and differentiation and NF1 individuals have osteoclast hyperactivity and increased bone resorption as measured by urine pyridinium crosslinks [pyridinoline (Pyd) and deoxypyridinoline (Dpd)]. Pyd and Dpd are hydroxylysine derived cross-links of collagen found in bone and cartilage and excreted in the urine. Dpd is most abundant in bone. The aim of this study was to evaluate if other syndromes of the Ras/MAPK pathway have increased bone resorption, which may impact the skeletal phenotype. METHODS AND RESULTS: Participants: [Noonan syndrome (n=14), Costello syndrome (n=21), and cardiofaciocutaneous (CFC) syndrome (n=14)]. Pyridinium cross-links from two consecutive first morning urines were extracted after acid hydrolysis and analyzed by High Performance Liquid Chromotography. Three separate analyses of covariance (ANCOVA) were performed to compare Pyd, Dpd, and Dpd/Pyd ratio of each group to controls after controlling for age. Data were compared to 99 healthy controls. CONCLUSIONS: The Dpd and the Dpd/Pyd ratio were elevated (p<0.0001) in all 3 conditions compared to controls suggesting that collagen degradation was predominantly from bone. The data suggest that the Ras/MAPK signal transduction pathway is important in bone homeostasis