54 research outputs found

    Differential postural effects of plantar-flexor muscles fatigue under normal, altered and improved vestibular and neck somatosensory conditions

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    The aim of the present study was to assess the effects of plantar-flexor muscles fatigue on postural control during quiet standing under normal, altered and improved vestibular and neck somatosensory conditions. To address this objective, young male university students were asked to stand upright as still as possible with their eyes closed in two conditions of No Fatigue and Fatigue of the plantar-flexor muscles. In Experiment 1 (n=15), the postural task was executed in two Neutral head and Head tilted backward postures, recognized to degrade vestibular and neck somatosensory information. In Experiment 2 (n=15), the postural task was executed in two conditions of No tactile and Tactile stimulation of the neck provided by the application of strips of adhesive bandage to the skin over and around the neck. Centre of foot pressure displacements were recorded using a force platform. Results showed that (1) the Fatigue condition yielded increased CoP displacements relative to the No Fatigue condition (Experiment 1 and Experiment 2), (2) this destabilizing effect was more accentuated in the Head tilted backward posture than Neutral head posture (Experiment 1) and (3) this destabilizing effect was less accentuated in the condition of Tactile stimulation than that of No tactile stimulation of the neck (Experiment 2). In the context of the multisensory control of balance, these results suggest an increased reliance on vestibular and neck somatosensory information for controlling posture during quiet standing in condition of altered ankle neuromuscular function

    The TESS-Keck Survey. XI. Mass Measurements for Four Transiting Sub-Neptunes Orbiting K Dwarf TOI-1246

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    Multiplanet systems are valuable arenas for investigating exoplanet architectures and comparing planetary siblings. TOI-1246 is one such system, with a moderately bright K dwarf (V = 11.6, K = 9.9) and four transiting sub-Neptunes identified by TESS with orbital periods of 4.31, 5.90, 18.66, and 37.92 days. We collected 130 radial velocity observations with Keck/HIRES and TNG/HARPS-N to measure planet masses. We refit the 14 sectors of TESS photometry to refine planet radii (2.97 +/- 0.06 R (circle plus), 2.47 +/- 0.08 R (circle plus), 3.46 +/- 0.09 R (circle plus), and 3.72 +/- 0.16 R (circle plus)) and confirm the four planets. We find that TOI-1246 e is substantially more massive than the three inner planets (8.1 +/- 1.1 M (circle plus), 8.8 +/- 1.2 M (circle plus), 5.3 +/- 1.7 M (circle plus), and 14.8 +/- 2.3 M (circle plus)). The two outer planets, TOI-1246 d and TOI-1246 e, lie near to the 2:1 resonance (P (e)/P ( d ) = 2.03) and exhibit transit-timing variations. TOI-1246 is one of the brightest four-planet systems, making it amenable for continued observations. It is one of only five systems with measured masses and radii for all four transiting planets. The planet densities range from 0.70 +/- 0.24 to 3.21 +/- 0.44 g cm(-3), implying a range of bulk and atmospheric compositions. We also report a fifth planet candidate found in the RV data with a minimum mass of 25.6 +/- 3.6 M (circle plus). This planet candidate is exterior to TOI-1246 e, with a candidate period of 93.8 days, and we discuss the implications if it is confirmed to be planetary in nature

    Sex‐Specific Differences in Clinical Outcomes After Percutaneous Coronary Intervention: Insights from the TAILOR‐PCI Trial

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    Background TAILOR‐PCI (Tailored Antiplatelet Initiation to Lessen Outcomes due to decreased Clopidogrel Response After Percutaneous Coronary Intervention) studied genotype‐guided selection of antiplatelet therapy after percutaneous coronary intervention versus conventional therapy with clopidogrel. The presence of CYP2C19 loss‐of‐function alleles in patients treated with clopidogrel may be associated with increased risk for ischemic events. We report a prespecified sex‐specific analysis of genotyping and associated cardiovascular outcomes from this study. Methods and Results Associations between sex and major adverse cardiac events (MACE: cardiovascular death, myocardial infarction, stroke, stent thrombosis, and severe recurrent ischemia) and Bleeding Academic Research Consortium (BARC) bleeding at 12 months were analyzed using Cox proportional‐hazards models. Among 5276 randomized patients, loss‐of‐function carriers were observed in ≈36% of both sexes, and >80% of carriers were heterozygotes. At 12 months, after adjustment for baseline differences, risks of MACE (HR , 1.28 [0.97 to 1.68]; P=0.088) and BARC bleeding (hazard ratio [HR], 1.36 [0.91 to 2.05]; P=0.14) were comparable among women and men. There were no significant interactions between sex and treatment strategy for MACE interaction P value (Pint=0.59) or BARC bleeding (Pint=0.47) nor for sex and genotype (MACE Pint=0.15, and BARC bleeding Pint=0.60). Conclusions CYP2C19 loss‐of‐function alleles were present in ≈1 in 3 women and men. Women had similar adjusted risks of MACE and bleeding as men following percutaneous coronary intervention. Genotype‐guided therapy did not significantly reduce the risk of MACE or bleeding relative to conventional therapy for both sexes. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01742117

    Identifying the roles of amino acids, alcohols and 1,2-diamines as mediators in coupling of haloarenes to arenes

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    Coupling of haloarenes to arenes has been facilitated by a diverse range of organic additives in the presence of KO(t)Bu or NaO(t)Bu since the first report in 2008. Very recently, we showed that the reactivity of some of these additives (e.g., compounds 6 and 7) could be explained by the formation of organic electron donors in situ, but the role of other additives was not addressed. The simplest of these, alcohols, including 1,2-diols, 1,2-diamines, and amino acids are the most intriguing, and we now report experiments that support their roles as precursors of organic electron donors, underlining the importance of this mode of initiation in these coupling reactions
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