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High intensity exercise can lead to depletion of CO2 from the body (hypocapnia). This disturbance becomes more noticeable during recovery or between seasons of intermittent exercise, putting the su...

The term gradient nano-chemo-mechanics was introduced to encompass models incorporating higher order couplings between deformation and chemistry at the nanoscale. Along these lines, the article first reviews the basics of a robust theoretical framework developed for such processes focusing on elasticity and diffusion. The classical laws for Hookean deformation and Fickean transport are modified to include extra Laplacian terms and corresponding internal lengths modeling nonlocal interactions. Then, special cases are considered to describe deformation and fracture aspects of new energy materials; namely Li-ion battery (LIB) nanostructured anodes and disclinated metallic microcrystals (DMC). Both of these material systems are characterized by a high degree of spatial gradient structures (SGS) with extended surface for energy storage and catalysis applications.

Summary The aim of the present study was to examine whether the exercise intensity corresponding to the lactate threshold may be predicted by the Maximum Phonation Time task (MPT). Ten Greek amateur football players (age: 18.4 ± 1.0 years), performed a graded cycling exercise test to exhaustion in order to determine lactate threshold. A number of physiological variables were measured including perceived exertion, cardiopulmonary values and blood lactate. The MPT variable was correlated with all of the physiological variables. Also, a binary logistic regression analysis was used to investigate whether MPT could predict lactate threshold. The ROC analysis showed specificity to be 0.90 and sensitivity to be 0.70 (optimal screening cutoff point for MPT 9.5 seconds). The results showed an odds ratio of 1.45 indicating a 45% increase in the probability of passing the threshold for every second there was a reduction in voice duration. MPT may be used as a simple, non-invasive, inexpensive method for monitoring exercise intensity during physical exercise. Further research is needed to measure its efficacy in bigger samples and in different sports.

Objective: Transcarotid/transcervical revascularisation (TCAR) is an alternative to carotid endarterectomy (CEA) and transfemoral carotid stenting (tfCAS). This review aimed to evaluate pooled data on patients undergoing TCAR. Data sources: Medline, Embase, Scopus, and Cochrane Library databases were used. Review methods: This systematic review was conducted under Systematic Reviews and Meta-Analysis guidelines. Eligible studies (published online up to September 2020) reported 30 day mortality and stroke/transient ischaemic attack (TIA) rates in patients undergoing TCAR. Data were pooled in a random effects model and weight of effect for each study was also reported. Quality of studies was evaluated according to Newcastle – Ottawa scale. Results: Eighteen studies (three low, seven medium, and eight high quality) included 4 852 patients (4 867 TCAR procedures). The pooled 30 day mortality rate was 0.7% (n = 32) (95% confidence interval [CI] 0.5 – 1.0), 30 day stroke rate 1.4% (n = 62) (95% CI 1.0 – 1.7), and 30 day stroke/TIA rate 2.0% (n = 92) (95% CI 1.4 – 2.7). Pooled technical success was 97.6% (95% CI 95.9 – 98.8). The cranial nerve injury rate was 1.2% (95% CI 0.7 – 1.9) (n = 14; data from 10 studies) while the early myocardial infarction (MI) rate was 0.4% (95% CI 0.2 – 0.6) (n = 16; data from 17 studies). The haematoma/bleeding rate was 3.4% (95% CI 1.7 – 5.8) (n = 135; data from 10 studies), with one third of these cases needing drainage or intervention. Within a follow up of 3 – 40 months the restenosis rate was 4% (95% CI 0.1 – 13.1) (data from nine studies; n = 64/530 patients) and death/stroke rate 4.5% (95% CI 1.8 – 8.4) (data from five studies; n = 184/3 742 patients). Symptomatic patients had a higher risk of early stroke/TIA than asymptomatic patients (2.5% vs. 1.2%; odds ratio 1.99; 95% CI 1.01 – 3.92); p =.046; data from eight studies). Conclusion: TCAR is associated with promising early and late outcomes, with symptomatic patients having a higher risk of early cerebrovascular events. More prospective comparative studies are needed in order to verify TCAR as an established alternative treatment technique. © 2021 European Society for Vascular Surgery

High intensity exercise can lead to depletion of CO

This study tested whether hypercapnic ventilatory response (HCVR) is affected by experience in apnoea and explored the possible underlying mechanisms of this phenomenon, with reference to maximum breath hold time (BHT). Elite apnoea divers (EBH=11) and novice subjects (NBH=10) performed a HCVR test (BM), which was repeated by the latter group on another day (PRE) after subjects executed five repeated maximum apnoeas. Subsequently, after a two week period of daily apnoea training, NBH subjects repeated HCVR test (POST). Diaphragmatic activity was recorded to determine apnoea easy going phase. Baseline HCVR of EBH was not lower than that of NBH. After execution of five apnoeas, HCVR in EBH decreased (P≤0.05) whereas it was not different among BM, PRE, and POST conditions in the NBH. Higher BHT and easy going phase values ensued from apnoea maneuvers in EBH than in NBH (PRE and POST), and in NBH POST compared to PRE condition (P≤0.05). HCVR was highly correlated (P≤0.05) with the cumulative easy going phase in EBH, PRE condition but nothing-similar observed in NBH, neither in PRE nor in POST conditions. These results indicate that at rest HCVR is not lower in experienced, than novice, skin divers; this response becomes dull after five repeated maximum apnoeas only in EBH. In the NBH group, two weeks of apnoea training are not adequate to affect HCVR despite an increase of BHT. It appears that after a repeated maximum apnoeas maneuver experienced skin divers improve BHT by extending easy going phase whereas NBH by other means.

The aim of this paper is to investigate the stress and the displacement field of a crack within a robust version of gradient elasticity, focusing at the standard Mode I, II, III problems. Special treatment is attributed to the crack configuration near its tip, deriving the gradient elasticity results that are analogous to the classical asymptotical solutions near the crack tip.

An account of non-singular solutions of gradient elasticity (GradEla) models for dislocations, along with clarifications of certain issues raised on previously published results, is given. Then, an extension to fractional GradEla solutions is pursued and certain preliminary results on this emerging topic are listed.

The simplest, yet robust, gradient elasticity theory (GRADELA) as first introduced by the last author is used to deduce nonsingular expressions for the stress and strain fields near dislocation lines and crack tips. These expressions are particularly useful for small volumes where the details of the deformation field need to be known for interpreting related experimental observations. Various implications are discussed in relation to the determination of the size of dislocation cores, the size of maximum stress or maximum strain in crack tips, and the interpretation of X-ray line profile measurements in determining internal stresses.

A non-singular gradient elasticity solution for the dislocation self-energy is employed and compared to previous results for 1/6(2023) partial dislocations fault in wurtzite GaN obtained by empirical potential calculations. Twenty-four previously obtained stable dislocation cores, twelve for each GaN polarity, are considered. It is shown that the gradient elasticity solution can be fitted to the atomistic simulations with good agreement and can be employed to trace the energetically favourable cores without the requirement of defining a core radius. As a byproduct of this continuum approach, a dislocation self-energy quantity is derived as a constant material property in terms of a gradient coefficient.

In this paper we present a novel method for detecting humans from laser range scans, where the core idea is to treat neither individual frames, which hold so little information that the task is impossible, nor motion patterns, as is the case with tracking methods. Rather, we map short time series of planar scans to 3D objects with time as the depth dimension; we then cluster and classify these 3D objects using unsupervised and off-line training, circumventing the need for predefining and parametrizing motion models. © 2012 The Author(s).

The aim of our study was to assess diurnal blood pressure (BP) and heart rate variability and their possible relationship to the duration of the QT interval in adolescents with Type 1 diabetes.In 48 normotensive, normoalbuminuric diabetic adolescents, with a mean (+/- sd) age of 17.3 (+/- 4.1) years and a mean (+/- sd) diabetes duration of 8.5 (+/- 3.3) years, 24-h ambulatory BP was recorded. In addition, 24-h heart rate (HR) monitoring was performed and QT and corrected QT (QTc) intervals were estimated as indices of autonomic function. The patients were divided into two groups according to the absence of a decrease (non-dippers) or the presence of a decrease (dippers) in nocturnal diastolic BP (DBP).In comparison with the dippers, the non-dippers showed reduced mean 24-h HR (79.6 vs. 84.0 beats/min, P = 0.05) and reduced mean daytime HR (81.3 vs. 86.0 beats/min, P = 0.05). The QT interval was prolonged in the non-dippers (366.3 vs. 347.5 ms, P = 0.015), and end systolic (28.7 vs. 25.9 mm, P = 0.004) and end diastolic left ventricular diameters (47.8 vs. 45.5 mm, P = 0.037) were greater. In stepwise multiple regression, HR variables were the most important factors affecting DBP ratio or the duration of the QT interval.In conclusion, normotensive diabetic adolescents with impaired nocturnal BP reduction also have impaired autonomic function tests, in association with prolonged QT interval and increased left ventricular diameters. These findings suggest that diabetic adolescents who have the 'non-dipper' phenomenon may need close follow-up for the possible development of vascular complications, such as cardiac arrhythmias and left-ventricular hypertrophy.