Thermoelectric-cooled terahertz quantum cascade lasers.

We demonstrate the first lasing emission of a thermo-electrically cooled terahertz quantum cascade laser (THz QCL). A high temperature three-well THz QCL emitting at 3.8 THz is mounted to a novel five-stage thermoelectric cooler reaching a temperature difference of ΔT = 124 K. The temperature and time-dependent laser performance is investigated and shows a peak pulse power of 4.4 mW and a peak average output power of 100 µW for steady-state operation.

Night-Time Heart Rate Variability during an Expedition to Mt Everest: A Case Report.

Mt Everest has been gaining popularity from casual hiking athletes, climbers, and ultra-endurance marathon runners. However, living and sleeping at altitude increases the risk of injury and illness. This is because travel to high altitudes adversely affects human physiology and performance, with unfavourable changes in body composition, exercise capacity, and mental function. This is a case report of a climber who reached the summit of Mt Everest from the north side. During his 40-day expedition, we collected sleep quality data and night-time heart rate variability. During the night inside the tent, the air temperature ranged from -12.9 to 1.8 °C (-5.8 ± 4.9 °C) and the relative humidity ranged from 26.1 to 78.9% (50.7 ± 16.9%). Awake time was 17.1 ± 6.0% of every sleep-time hour and increased with altitude (r = 0.42). Sleep time (r = -0.51) and subjective quality (r = 0.89) deteriorated with altitude. Resting heart rate increased (r = 0.70) and oxygen saturation decreased (r = -0.94) with altitude. The mean NN, RMSSD, total power, LF/HF, and SD1 and SD2 were computed using the NN time series. Altitude reduced the mean ΝΝ (r = -0.73), RMSSD (r = -0.31), total power (r = -0.60), LF/HF ratio (r = -0.40), SD1 (r = -0.31), and SD2 (r = -0.70). In conclusion, this case report shows that sleeping at high altitudes above 5500 m results in progressively reduced HRV, increased awakenings, as well as deteriorated sleep duration and subjective sleep quality. These findings provide further insight into the effects of high altitude on cardiac autonomic function and sleep quality and may have implications for individuals who frequently spend time at high altitudes, such as climbers.

Organ donation in the US and Europe: The supply vs demand imbalance.

Organ donation and transplantation remain the best and most cost-effective clinical solution for end-stage organ failure. Several agencies across the US and Europe provide legislative, regulatory, and humanitarian services to generate smoother applications in all transplantation processes and donor-recipient relationships. US and European statistics present nine types of grafts, with kidneys being the most transplanted organ worldwide. However, organ shortage, religion, underrepresented minority groups, difficulties in obtaining consent, lack of understanding, and general ethical concerns present challenging barriers to organ donation, reflecting the complexity of graft procurement and allocation. Breaking down these barriers to reduce the organ-supply imbalance requires an appropriate multifaceted approach. Some of the key areas include increasing the potential donor pool and consent rates, apt organ allocation, and improving organ health. Additionally, suitable policies and standardized guidelines for both donors and recipients, alongside educational initiatives, are needed to ensure patient safety and global awareness. Looking forward, novel and effective research plans and initiatives are needed if we are to avoid a colossal supply-demand gap.

Impact of Design on Medical Device Safety.

The growing number of emerging medical technologies and sophistication of modern medical devices (MDs) that improve both survival and quality of life indexes are often challenged by alarming cases of vigilance data cover-up and lack of sufficient pre- and post-authorization controls. Combining Quality with Risk Management processes and implementing them as early as possible in the design of MDs has proven to be an effective strategy to minimize residual risk. This article aims to discuss how the design of MDs interacts with their safety profile and how this dipole of intended performance and safety may be supported by Human Factors Engineering (HFE) throughout the Total Product Life-Cycle (TPLC) of an MD in order to capitalize on medical technologies without exposing users and patients to unnecessary risks.

Associations of polymorphisms of eight muscle- or metabolism-related genes with performance in Mount Olympus marathon runners.

Athletic endurance performance is probably partly under genetic control, but genetic association studies have yielded inconclusive results. The objective of the present study was to evaluate the association of polymorphisms in eight muscle- or metabolism-related genes with endurance performance in participants of the Olympus Marathon running race. We recruited 438 athletes who participated in the 2007 and 2008 annual running events of the Olympus Marathon: a 43.8-km race with an ascent from sea level to 2,690-m altitude and then a descent to 300 m. Phenotypes of interest were the competitive event time at the specific Olympus Marathon where the athlete was enrolled, the fastest reported timing ever achieved in an Olympus Marathon, and how many kilometers per week the athlete ran during the previous year. Eleven polymorphisms in alpha(3)-actinin (ACTN3), AMP deaminase-1 (AMPD1), bradykinin B(2) receptor (BDKRB2), beta(2)-adrenergic receptor (ADRB2), peroxisome proliferator-activated receptor (PPAR)-gamma coactivator-1 alpha (PPARGC1A), PPAR-alpha (PPARA), PPAR-delta (PPARD), and apoliprotein E (APOE) were evaluated. Hardy-Weinberg equilibrium testing on the overall cohort of male athletes showed a significant deviation for BDKRB2 rs1799722 (P = 0.018; P = 0.006 when limited to 316 habitual male runners) with an excess of the TT genotype. Across all athletes, no associations showed nominal statistical significance for any of the three phenotypes, and the same was true when analyses were limited to men (n = 417). When limited to 316 male athletes who identified running as their preferred sport, ADRB2 rs1042713 had nominally significant associations with faster times for the minor (A) allele for the fastest time ever (P = 0.01). The direction of effect was identical as previously postulated only for BDKRB2 rs1799722 and ADRB2 rs1042713, indicating consistency. BDKRB2 rs1799722 and ADRB2 rs1042713 have some support for being implicated in endurance performance among habitual runners and require further investigation.

Doctors' versus patients' global assessments of treatment effectiveness: empirical survey of diverse treatments in clinical trials.

OBJECTIVE: To examine whether doctors' global assessments of treatment effects agree with patients' global assessments. DESIGN: Survey of trials included in systematic reviews of treatments for diverse conditions. DATA SOURCES: Cochrane database of systematic reviews. Data extracted Data on patients' global assessments and on doctors' global assessment for the same treatment against the same comparator. MAIN OUTCOME MEASURES: Relative odds ratio (ratio of odds ratios of global improvement with the experimental intervention versus control according to doctors compared with patients), and improvement rates according to doctors and patients. RESULTS: Doctors' global assessments were compared with patients' global assessments for 63 different treatment comparisons (240 trials) in 18 conditions. The summary relative odds ratio across the comparisons was not significant (0.98, 95% confidence interval 0.88 to 1.08; I(2)=0%, 95% confidence interval 0% to 30%). In 62 of the 63 comparisons the effects of treatment rated by patients and by doctors did not differ beyond chance, but for single comparisons the confidence intervals were large. Rates of improvement on average did not differ between doctors' assessments and patients' assessments (summary relative odds ratio 0.98, 0.88 to 1.06; I(2)=0%, 0% to 24%). CONCLUSION: Doctors' global assessments of the effects of treatments are on average similar to those of patients.

The ACE gene insertion/deletion polymorphism and elite endurance swimming.

Human physical performance is influenced by genetic factors. A variation in the human angiotensin I-converting enzyme (ACE) gene has been identified, in which the insertion (I) variant may be associated with elite endurance performance, and the deletion (D) variant seems overrepresented amongst elite sprinters and short-distance swimmer status. We might thus anticipate I-allele frequency to be elevated amongst swimmers competing over very much greater distances, and have examined this hypothesis. Thirty-five truly elite very-long-distance swimmers were classified as better at 1- to 10-km distances (n=19, SLD group) or those best at 25-km races (n=16, LLD group). Genotype frequencies (II versus ID versus DD) differed between the two groups: 6% versus 47% versus 47% for SLD, and 18.8% versus 75% versus 6.2% for LLD (P=0.01). I-allele frequency was 0.29 for the shorter distance swimmers, and 0.59 for the 25 km group. These data are consistent with an association of ACE I allele with longer distance swimming, and the ACE D allele with swimming shorter distances.