The Effects of Low and Moderate Dose Caffeine Supplementation on Upper and Lower Body Maximal Voluntary Concentric and Eccentric Muscle Force

Despite the growing quantity of literature exploring the effect of caffeine on muscular strength, there is a dearth of data that directly explores differences in erogenicity between upper and lower body musculature and the dose response effect. The present study sought to investigate the effects of low and moderate dose caffeine on the maximal voluntary strength of the elbow flexors and knee extensors. Ten non-specifically strength trained, recreationally active participants (21 ± 0.3 yrs) completed the study. Using a randomised, counterbalanced and double blind approach, isokinetic concentric and eccentric strength was measured at 60 and 180 deg/s following administration of a placebo, 3 mg・kg−1 body mass caffeine and 6 mg・kg−1 body mass caffeine. There was no effect of caffeine on the maximal voluntary concentric and eccentric strength of the elbow flexors, or the eccentric strength of the knee extensors. Both 3 and 6 mg・kg−1 body mass caffeine caused a significant increase in peak concentric force of the knee extensors at 180 deg/s. No difference was apparent between the two concentrations. Only 6 mg・kg−1 body mass caused an increase in peak concentric force during repeated contractions. The results infer that the effective caffeine concentration to evoke improved muscle performance may be related to muscle mass and contraction type. The present work indicates that relatively low dose caffeine treatment may be effective for improving lower body muscular strength, but may have little benefit for the strength of major muscular groups of the upper body.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Définir des priorités de recherche à l’échelle du Canada pour les programmes de simulation agréés par le Collège royal

To advance the field of health sciences simulation, research must be of high quality and would benefit from multi-institutional collaboration where centres can leverage and share expertise as well as work together to overcome limits to the generalizability of research findings from single-institution studies. A needs assessment in emergency medicine simulation has illustrated the importance of identifying research priorities in Canada. The main purpose of this study was to identify simulation research priority directions for Canadian simulation centres. The current survey study drew on 16 research priorities developed through a two-round internal Delphi study at McGill University that 15 of 17 simulation centre advisory board members participated in. The final 16 research priorities were then rated by a total of 18 of 24 simulation centre directors and/or delegates contacted from 15 of 19 Royal College of Physicians and Surgeons of Canada-accredited simulation centres in Canada. Results revealed 9 common research priorities that reached 70% or higher agreement for all respondents. We anticipate that our findings can contribute to building a shared vision of priorities, community, and collaboration to enhance health care simulation research quality amongst Canadian simulation centres.Pour faire progresser le domaine de la simulation en sciences de la santé, il faut tendre vers une recherche de haute qualité, qui serait favorisée par une collaboration multi-institutionnelle permettant aux programmes de tirer parti de leur expertise, de la partager et de surmonter les limites de la généralisabilité des résultats de recherche provenant d’études menées dans un seul établissement. Une évaluation des besoins en matière de simulation en médecine d’urgence a illustré l’importance de définir des priorités de recherche à l’échelle du Canada. Le principal objectif de cette étude était de dresser les orientations prioritaires des programmes de simulation canadiens pour la recherche en simulation. Elle est basée sur 16 priorités de recherche dégagées d’une étude Delphi à deux tours réalisée à l’Université [masqué], à laquelle 15 des 17 membres du comité consultatif de son centre de simulation ont participé. Les 16 priorités de recherche finales ont ensuite été évaluées par 18 des 24 directeurs ou délégués de centres de simulation contactés, provenant de 15 des 19 programmes de simulation agréés par le Collège royal des médecins et chirurgiens du Canada. Les résultats font état de neuf priorités de recherche communes ayant obtenu un taux d’accord de 70 % ou plus parmi l’ensemble des répondants. Nous pensons que nos résultats peuvent contribuer à l’élaboration d’une vision commune des priorités parmi les programmes de simulation canadiens, à la création d’une communauté de pratique et à une collaboration pour améliorer la qualité de la recherche en simulation dans le domaine des soins de santé

Spatially uniform single-qubit gate operations with near-field microwaves and composite pulse compensation

We present a microfabricated surface-electrode ion trap with a pair of integrated waveguides that generate a standing microwave field resonant with the 171Yb+ hyperfine qubit. The waveguides are engineered to position the wave antinode near the center of the trap, resulting in maximum field amplitude and uniformity along the trap axis. By calibrating the relative amplitudes and phases of the waveguide currents, we can control the polarization of the microwave field to reduce off-resonant coupling to undesired Zeeman sublevels. We demonstrate single-qubit pi-rotations as fast as 1 us with less than 6 % variation in Rabi frequency over an 800 um microwave interaction region. Fully compensating pulse sequences further improve the uniformity of X-gates across this interaction region.Comment: 14 pages, 8 figure

Controlling trapping potentials and stray electric fields in a microfabricated ion trap through design and compensation

Recent advances in quantum information processing with trapped ions have demonstrated the need for new ion trap architectures capable of holding and manipulating chains of many (>10) ions. Here we present the design and detailed characterization of a new linear trap, microfabricated with scalable complementary metal-oxide-semiconductor (CMOS) techniques, that is well-suited to this challenge. Forty-four individually controlled DC electrodes provide the many degrees of freedom required to construct anharmonic potential wells, shuttle ions, merge and split ion chains, precisely tune secular mode frequencies, and adjust the orientation of trap axes. Microfabricated capacitors on DC electrodes suppress radio-frequency pickup and excess micromotion, while a top-level ground layer simplifies modeling of electric fields and protects trap structures underneath. A localized aperture in the substrate provides access to the trapping region from an oven below, permitting deterministic loading of particular isotopic/elemental sequences via species-selective photoionization. The shapes of the aperture and radio-frequency electrodes are optimized to minimize perturbation of the trapping pseudopotential. Laboratory experiments verify simulated potentials and characterize trapping lifetimes, stray electric fields, and ion heating rates, while measurement and cancellation of spatially-varying stray electric fields permits the formation of nearly-equally spaced ion chains.Comment: 17 pages (including references), 7 figure

Demonstration of integrated microscale optics in surface-electrode ion traps

In ion trap quantum information processing, efficient fluorescence collection is critical for fast, high-fidelity qubit detection and ion-photon entanglement. The expected size of future many-ion processors require scalable light collection systems. We report on the development and testing of a microfabricated surface-electrode ion trap with an integrated high numerical aperture (NA) micromirror for fluorescence collection. When coupled to a low NA lens, the optical system is inherently scalable to large arrays of mirrors in a single device. We demonstrate stable trapping and transport of 40Ca+ ions over a 0.63 NA micromirror and observe a factor of 1.9 enhancement in photon collection compared to the planar region of the trap.Comment: 15 pages, 8 figure

Riverine dissolved inorganic carbon export from the Southeast Alaskan Drainage Basin with implications for coastal ocean processes

Dissolved inorganic carbon (DIC) represents an important but poorly constrained form of lateral carbon flux to the oceans. With high precipitation rates, large glaciers, and dense temperate rainforest, Southeast Alaska plays a critical role in the transport of carbon to the Gulf of Alaska (GOA). Previous estimates of DIC flux across the Southeast Alaska Drainage Basin (SEAKDB) are poorly constrained in space and time. Our goal was to incorporate recent measurements of DIC concentrations with previous measurements from the U.S. Geological Survey in order to model the spatial and temporal patterns of riverine DIC transport from SEAK to the GOA. We aggregated DIC concentration measurements from 1957 to 2020 and associated measurements of mean daily discharge. We then constructed load estimation models to generate concentration predictions across 24 watersheds. By spatially matching measurements of DIC with SEAKDB watersheds, we extrapolated concentration predictions across 2,455 watersheds encompassing approximately 190,000 km2. Models were aggregated according to two factors, the presence of karst and the discharge regime. Finally, monthly flux predictions were generated for each watershed using predicted concentrations and runoff estimates from the Distributed Climate Water Balance Model. Mean annual DIC flux from the SEAKDB was 2.36 Tg C with an average yield of 12.52 g C m−2. Both karst presence and flow regimes modified DIC flux and speciation across coastal marine areas. The high resolution of DIC flux estimates will provide useful inputs for describing seasonal C dynamics, and further refines our understanding of C budgets in the Pacific temperate rainforest and the surrounding marine environment.National Science Foundation. Oak Ridge Institute for Science and Education.Abstract -- Plain Language Summary -- 1. Introduction -- 2. Methods -- 3. Results -- 4. Discussion -- 5. Conclusions -- Data Availability Statement -- Acknowledgements -- References.Ye

Cytoplasmic p53 couples oncogene-driven glucose metabolism to apoptosis and is a therapeutic target in glioblastoma.

Cross-talk among oncogenic signaling and metabolic pathways may create opportunities for new therapeutic strategies in cancer. Here we show that although acute inhibition of EGFR-driven glucose metabolism induces only minimal cell death, it lowers the apoptotic threshold in a subset of patient-derived glioblastoma (GBM) cells. Mechanistic studies revealed that after attenuated glucose consumption, Bcl-xL blocks cytoplasmic p53 from triggering intrinsic apoptosis. Consequently, targeting of EGFR-driven glucose metabolism in combination with pharmacological stabilization of p53 with the brain-penetrant small molecule idasanutlin resulted in synthetic lethality in orthotopic glioblastoma xenograft models. Notably, neither the degree of EGFR-signaling inhibition nor genetic analysis of EGFR was sufficient to predict sensitivity to this therapeutic combination. However, detection of rapid inhibitory effects on [18F]fluorodeoxyglucose uptake, assessed through noninvasive positron emission tomography, was an effective predictive biomarker of response in vivo. Together, these studies identify a crucial link among oncogene signaling, glucose metabolism, and cytoplasmic p53, which may potentially be exploited for combination therapy in GBM and possibly other malignancies