Effects of increasing cold exposure on the oxygen uptake of walking unloaded and loaded.

Introduction: Cold exposure and load carriage is an understudied area. Most research shows that VO2max is generally unaffected by cold exposure, however the majority of research suggests that sub-maximal O2 consumption increases for a given workload [1]. This pilot study assessed the effects of cold on load carriage. Methods: 4 male participants (age: 21.8 ± 3.4 years, height: 182.5 ±5.0 cm, weight: 77.8 ± 13.5 kg) completed a walking protocol of ~1 hour in a range of different ambient temperatures within an environmental chamber (20 °C, 10 °C, 5 °C, 0 °C, -5 °C and -10 °C). Humidity was controlled at ~50% while altitude was 0 m (20.95% FiO2). Participants wore shorts and t-shirt for all trials. The protocol included a 15 minute rest period, unloaded walking at 4 km.hr-1 for 4 minutes at 0% and 10% gradient. The same workloads were repeated loaded (18 kg) after a 5 minute rest. Heart rate returned to resting levels before each exercise section to ensure prior activity did not influence findings. Unloaded walking was then repeated. Expired air was collected and analysed using a Cortex 3B Metalyzer (Germany). Statistical analysis was performed using SPSS version 22, with significance denoted by p < 0.05. Results: Table ​Table1 shows a significant increase in VO2 with load (p = 0.019). At all workloads, significant increases in VO2 were associated with decreasing temperature (p = 0.048). ΔVO2 values suggest that the effect of loading was consistent, regardless of ambient temperature (p = 0.997). When comparing the first unloaded exercise bout with the second, VO2 for 20 °C, 10 °C and 5 °C was similar, whereas at 0 °C and below, VO2 was higher in the second unloaded bout, but this interaction was not significant (p = 0.158)

The Effect of Prolonged Physical Activity Performed during Extreme Caloric Deprivation on Cardiac Function

Background: Endurance exercise may induce transient cardiac dysfunction. Data regarding the effect of caloric restriction on cardiac function is limited. We studied the effect of physical activity performed during extreme caloric deprivation on cardiac function. Methods: Thirty-nine healthy male soldiers (mean age 2060.3 years) were studied during a field training exercise lasted 85– 103 hours, with negligible food intake and unlimited water supply. Anthropometric measurements, echocardiographic examinations and blood and urine tests were performed before and after the training exercise. Results: Baseline VO2 max was 5965.5 ml/kg/min. Participants ’ mean weight reduction was 5.760.9 kg. There was an increase in plasma urea (11.662.6 to 15.863.8 mmol/L, p,0.001) and urine osmolarity (6926212 to 10946140 mmol/kg, p,0.001) and a decrease in sodium levels (140.561.0 to 136.662.1 mmol/L, p,0.001) at the end of the study. Significant alterations in diastolic parameters included a decrease in mitral E wave (93.6 to 83.5 cm/s; p = 0.003), without change in E/A and E/E9 ratios, and an increase in iso-volumic relaxation time (73.9 to 82.9 ms, p = 0.006). There was no change in left or right ventricular systolic function, or pulmonary arterial pressure. Brain natriuretic peptide (BNP) levels were significantly reduced post-training (median 9 to 0 pg/ml, p,0.001). There was no elevation in Troponin T or CRP levels. On multivariate analysis, BNP reduction correlated with sodium levels and weight reduction (R = 0.8, p,0.001)

Dietary intake and stress fractures among elite male combat recruits

<p>Abstract</p> <p>Background</p> <p>Appropriate and sufficient dietary intake is one of the main requirements for maintaining fitness and health. Inadequate energy intake may have a negative impact on physical performance which may result in injuries among physically active populations. The purpose of this research was to evaluate a possible relationship between dietary intake and stress fracture occurrence among combat recruits during basic training (BT).</p> <p>Methods</p> <p>Data was collected from 74 combat recruits (18.2 ± 0.6 yrs) in the Israeli Defense Forces. Data analyses included changes in anthropometric measures, dietary intake, blood iron and calcium levels. Measurements were taken on entry to 4-month BT and at the end of BT. The occurrence of stress reaction injury was followed prospectively during the entire 6-month training period.</p> <p>Results</p> <p>Twelve recruits were diagnosed with stress fracture in the tibia or femur (SF group). Sixty two recruits completed BT without stress fractures (NSF). Calcium and vitamin D intakes reported on induction day were lower in the SF group compared to the NSF group-38.9% for calcium (589 ± 92 and 964 ± 373 mg·d^-1, respectively, <it>p </it>< 0.001), and-25.1% for vitamin D (117.9 ± 34.3 and 157.4 ± 93.3 IU·d^-1, respectively, <it>p </it>< 0.001). During BT calcium and vitamin D intake continued to be at the same low values for the SF group but decreased for the NSF group and no significant differences were found between these two groups.</p> <p>Conclusions</p> <p>The development of stress fractures in young recruits during combat BT was associated with dietary deficiency before induction and during BT of mainly vitamin D and calcium. For the purpose of intervention, the fact that the main deficiency is before induction will need special consideration.</p

The TOBY Study. Whole body hypothermia for the treatment of perinatal asphyxial encephalopathy: A randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>A hypoxic-ischaemic insult occurring around the time of birth may result in an encephalopathic state characterised by the need for resuscitation at birth, neurological depression, seizures and electroencephalographic abnormalities. There is an increasing risk of death or neurodevelopmental abnormalities with more severe encephalopathy. Current management consists of maintaining physiological parameters within the normal range and treating seizures with anticonvulsants.</p> <p>Studies in adult and newborn animals have shown that a reduction of body temperature of 3–4°C after cerebral insults is associated with improved histological and behavioural outcome. Pilot studies in infants with encephalopathy of head cooling combined with mild whole body hypothermia and of moderate whole body cooling to 33.5°C have been reported. No complications were noted but the group sizes were too small to evaluate benefit.</p> <p>Methods/Design</p> <p>TOBY is a multi-centre, prospective, randomised study of term infants after perinatal asphyxia comparing those allocated to "intensive care plus total body cooling for 72 hours" with those allocated to "intensive care without cooling".</p> <p>Full-term infants will be randomised within 6 hours of birth to either a control group with the rectal temperature kept at 37 +/- 0.2°C or to whole body cooling, with rectal temperature kept at 33–34°C for 72 hours. Term infants showing signs of moderate or severe encephalopathy +/- seizures have their eligibility confirmed by cerebral function monitoring. Outcomes will be assessed at 18 months of age using neurological and neurodevelopmental testing methods.</p> <p>Sample size</p> <p>At least 236 infants would be needed to demonstrate a 30% reduction in the relative risk of mortality or serious disability at 18 months.</p> <p>Recruitment was ahead of target by seven months and approvals were obtained allowing recruitment to continue to the end of the planned recruitment phase. 325 infants were recruited.</p> <p>Primary outcome</p> <p>Combined rate of mortality and severe neurodevelopmental impairment in survivors at 18 months of age. Neurodevelopmental impairment will be defined as any of:</p> <p>• Bayley mental developmental scale score less than 70</p> <p>• Gross Motor Function Classification System Levels III – V</p> <p>• Bilateral cortical visual impairments</p> <p>Trial Registration</p> <p>Current Controlled Trials ISRCTN89547571</p

Can mHealth Technology Help Mitigate the Effects of the COVID-19 Pandemic?

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Glucose mediated synthesis of gold nanoshells: A facile and eco-friendly approach conferring high colloidal stability

In this paper, we report a novel, eco-friendly method for the preparation of gold nanoshells (GNS) with unprecedented colloidal stability. Gold shell layers were grown on silica nanospheres by utilizing glucose. Nanoshell morphology was optimized by varying the molar ratio of glucose to gold, and was characterized using UV-vis spectroscopy and transmission electron microscopy (TEM). The colloidal stability of the prepared nanoshells was compared to those made using formaldehyde reductant, using sequential extinction intensity measurements and electron microscopy. Fourier transform infrared spectroscopy was used to elucidate their surface chemistry. Uniformity and homogeneity in the shells was achieved at a molar ratio of 2, followed by shell thinning at higher glucose concentrations. These colloids exhibited remarkable stability, compared to those prepared with the commonly reported protocol, where formaldehyde is employed as the reducing agent. The key role played by glucose in imparting high stability, in conjunction with its reducing properties is demonstrated. Furthermore, the sensing potential of these nanoshells was demonstrated using surface enhanced Raman scattering (SERS) in the near-infrared region on an optical fiber platform. The present approach offers an eco-friendly route for the production of nanoshells with high stability, augmenting their use for sensing and in vivo applications, where highly stable and unaggregated nanoshells are preferred. By eliminating the routinely used noxious formaldehyde, this method presents itself as a safe, scalable and direct route for the synthesis of glucose capped nanoshells, which are much sought after for therapeutic applications

Facile synthesis of size and wavelength tunable hollow gold nanostructures for the development of a LSPR based label-free fiber-optic biosensor

Hollow bimetallic nanostructures have recently emerged as attractive plasmonic materials due to the ease of optical tunability by changing their size/composition. Currently available methods, in addition to being tedious and time-consuming, result in polydispersed nanostructures, particularly due to polydispersed templates. In this study, optically tunable hollow gold nanostructures (HGNS) were synthesized by galvanic replacement reaction between silver nanospheres (AgNS) templates and gold salt. Monodispersed AgNS were created using a gold seed-mediated heteroepitaxial growth. Since it is easier to ensure monodispersed gold nanosphere seeds, the resulting AgNS showed a tight control on size. Hollow gold nanostructures 43-70 nm in size with extinction maxima ranging between 450-590 nm were produced by varying the gold to silver molar ratio. The nanostructures were observed to be monodispersed and uniform (SD <= 11%) in all the batches. Furthermore, the synthesized HGNS were immobilized on dendrimer-functionalized U-shaped fiber-optic probes to develop a localized surface plasmon resonance (LSPR) based sensor. Refractive index sensitivity of the HGNS based sensors was found to be 1.5-fold higher than solid gold nanosphere (GNS)-based fiber-optic sensors. These HGNS-based fiber-optic probes were subsequently used to develop an immunosensor with improved sensitivity by using human immunoglobulin-G (HIgG) as receptor molecules and goat-anti-HIgG as a target analyte

Facile Synthesis of Size-Tunable Silver Nanoparticles by Heteroepitaxial Growth Method for Efficient NIR SERS

We report a rapid and facile method to synthesize highly monodispersed silver nanoparticles (AgNP) by heteroepitaxial growth method using gold seed particles (size similar to 2 nm). Silver was deposited on gold seed particles by Tollen's reaction. The presence of seed particles provided good control on the morphology and size distribution of AgNP, achieving the standard deviation in size a parts per thousand currency sign11 %. The real-time kinetics of AgNP formation revealed that the presence of gold seed particles increased the reaction rate by 7-fold compared to seedless approach. The size and extinction maxima of AgNP were tunable by varying the gold seed particles to silver molar ratio. This new heteroepitaxial growth method of AgNP synthesis is simple, fast (completing the reaction within 3 min), and eco-friendly to yield monodispersed nanoparticles. Further, these AgNP were used to develop efficient surface-enhanced Raman scattering (SERS) substrates for sensing applications which showed good repeatability and significantly improved enhancement factors in the near-infrared (NIR) region

Fabrication of miniature elastomer lenses with programmable liquid mold for smartphone microscopy: curing polydimethylsiloxane with in situ curvature control

Miniature lenses can transform commercial imaging systems, e.g., smartphones and webcams, into powerful, low-cost, handheld microscopes. To date, the reproducible fabrication of polymer lenses is still a challenge as they require controlled dispensing of viscous liquid. This paper reports a reproducible lens fabrication technique using liquid mold with programmable curvature and off-the-shelf materials. The lens curvature is controlled during fabrication by tuning the curvature of an interface of two immiscible liquids [polydimethylsiloxane (PDMS) and glycerol]. The curvature control is implemented using a visual feedback system, which includes a software-based guiding system to produce lenses of desired curvature. The technique allows PDMS lens fabrication of a wide range of sizes and focal lengths, within 20 min. The fabrication of two lens diameters: 1 and 5 mm with focal lengths ranging between 1.2 and 11 mm are demonstrated. The lens surface and bulk quality check performed using X-ray microtomography and atomic force microscopy reveal that the lenses are suitable for optical imaging. Furthermore, a smartphone microscope with similar to 1.4-mu m resolution is developed using a self-assembly of a single high power fabricated lens and microaperture. The lenses have various potential applications, e.g., optofluidics, diagnostics, forensics, and surveillance. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE