252 research outputs found
TMP-cadmiate: A base for Efficient and Chemoselective Deprotonative Metallation Reactions of Aromatic Compounds
International audienceEfficient deprotonative cadmiation reactions of functionalized aromatics including heterocycles have been realized using TMP-cadmiate, (TMP)3CdLi (TMP = 2,2,6,6-tetramethylpiperidino). The reagent is compatible with reactive functional groups (amide, ester, nitrile and even ketone functions), heavy halogens (Br, I), five-membered aromatic heterocycles (furan, thiophene, oxazole, thiazole, and pyrrole derivatives) and even aromatic aza-heterocycles (pyridine, diazine compounds). Some heterocycles benefiting from doubly activated positions can be dimetallated at room temperature. The deprotonative cadmiation pathways/mechanisms have been studied using computational/theoretical techniques. The lithium arylcadmiates such generated have been evidenced using iodine. Alternative trappings of the species are palladium-catalyzed cross-coupling reactions or simple quench with acid chlorides
Slow movement resistance training in women
A resistance training protocol of low intensity and short duration allows for increased training frequency and improved compliance. This study aimed to examine the short-term (response of growth hormone (GH) and testosterone after one exercise session) and long-term (change of fitness level and body fat percentage after the exercise period) effects of slow movement resi- stance training using the individual’s body mass (hiroNARI style training) in adult women and to clarify their subjective sense of training contin- uity. Nineteen healthy adult women performed hiroNARI style training three times a week for 12 weeks. This protocol consisted of 12 types of exercise for 7 muscle groups. GH and testos-terone increased significantly after one exercise session (70% and 23.3%, p < 0.05, respectively). Height and the circumferences of the upper arm (flexed), chest, waist, hip, and thigh changed si- gnificantly. Except for the upper arm circumfe- rence, these parameters improved significantly after 6 weeks. There were significant improvem- ents in measurements of physical fitness after 6 weeks including one leg raise with eyes closed, side step, and repeated sit ups for 30 s. After 12 weeks, anteflexion from a long sitting position improved as well. Triglycerides and HDL and LDL cholesterol changed significantly after 12 weeks. In conclusion, resistance training may have po- sitive effects and is associated with high comp- liance. However, it will be necessary to reexam- ine the training protocol for increasing back and lower limb muscle strength and necessary vari- ations to prevent overtraining of certain muscle groups
Influence of cell phone email use on characteristics of gait
Previously, gait had been considered an automatic and rhythmical movement that uses minimal attentional resources. The relationship between attention and gait has been revealed in recent research. However, in young adults in particular, the influence of using a cell phone - which is used frequently in daily life and considered to require high attentional demands - on gait has not been demonstrated. In this study, we examined the influence of mobile phone use on gait. Thirty healthy college students (15 males, 15 females) walked through a normal straight course with or without an obstacle under two different walking conditions while either using the email function of the cell phone or walking without a cell phone. The participants walked at a normal speed on a 10-m walkway. In walking conditions with an obstacle, an obstacle (17 cm in height) was set at the mid-point of the walkway. The following gait parameters were calculated: velocity, stride length, stride width (cm), and stance phase of one foot (just before an obstacle, one and two steps before the obstacle). Velocity and stride width decreased and the stance phase increased during walking while operating a cell phone. The stance phase just before an obstacle and stride length increased while operating a cell phone with an obstacle in the way. Gaze fixations and the high attention required to use the email function of the device may result in greatly disturbed gait. © 2009 European College of Sport Science
The role of eye movement in upright postural control
金沢大学人間社会研究域人間科学系秋田県立大学 総合科学教育研究センターVision contributes to upright postural control by providing afferent feedback to the cerebellum. Vision is generally classified into central and peripheral vision. In measurements of postural sway, in which participants are required to maintain a stable upright posture while fixating on a visual target, non-retinal eye positional information due to the fixation is used as well as the retinal information from both visual fields. However, little is known about the role of non-visual eye positional information in postural control. This study examined the role of non-visual eye position information in upright postural control by comparing participants\u27 centre of pressure (COP) sway between two experimental conditions: (1) a space-fixed visual target condition (control), in which eye movement was not controlled, and (2) a head-fixed visual target condition (treatment), in which eye movement was inhibited. Using 12 university students, COP sway and electrooculograms (EOG) were measured under both conditions. In the space-fixed condition, participants maintain an upright posture while fixating on a visual target fixed on a screen 1 m in front of them. In the head-fixed condition, participants maintained an upright posture while gazing at a target moving in sync with their head sway on the screen. The COP was evaluated by path length, area, root mean square, velocity and position. Eye movements were evaluated by the mean eye movement angle. The mean eye movement angle was significantly larger in the vertical direction then in the horizontal direction in both experimental conditions and was also found to be larger in the space-fixed condition than in the head-fixed condition. No significant different was found in any COP parameter between both conditions. It was suggested that non-visual eye position information from the external eye muscles to the sensory perception system contributes little to postural stabilisation under the measurement conditions used in this study. © Springer-Verlag Italia 2009
Slow movement resistance training in women
A resistance training protocol of low intensity and short duration allows for increased training frequency and improved compliance. This study aimed to examine the short-term (response of growth hormone (GH) and testosterone after one exercise session) and long-term (change of fitness level and body fat percentage after the exercise period) effects of slow movement resi- stance training using the individual’s body mass (hiroNARI style training) in adult women and to clarify their subjective sense of training contin- uity. Nineteen healthy adult women performed hiroNARI style training three times a week for 12 weeks. This protocol consisted of 12 types of exercise for 7 muscle groups. GH and testos-terone increased significantly after one exercise session (70% and 23.3%, p < 0.05, respectively). Height and the circumferences of the upper arm (flexed), chest, waist, hip, and thigh changed si- gnificantly. Except for the upper arm circumfe- rence, these parameters improved significantly after 6 weeks. There were significant improvem- ents in measurements of physical fitness after 6 weeks including one leg raise with eyes closed, side step, and repeated sit ups for 30 s. After 12 weeks, anteflexion from a long sitting position improved as well. Triglycerides and HDL and LDL cholesterol changed significantly after 12 weeks. In conclusion, resistance training may have po- sitive effects and is associated with high comp- liance. However, it will be necessary to reexam- ine the training protocol for increasing back and lower limb muscle strength and necessary vari- ations to prevent overtraining of certain muscle groups
Influence of high ambient temperatures on the physiological responses and body sway in healthy young adults after quickly standing.
This study was aimed to compare the variations in cerebral oxygenation, blood pressure and center-of-foot pressure after standing from sitting and supine positions at normal (22 degrees C) and high (32 degrees C) room temperatures. Thirty young adults stood up from a resting posture (sitting or supine position) and kept the static standing posture for 90 sec. Meanwhile, their center-of-foot pressure (COP), blood pressure, and cerebral oxygenation kinetics were measured in continuity. The change of the frequency domain low-to-high frequency (LF/HF) ratio of the R-R interval before and after standing from a supine position was significantly higher than that from a sitting position under both temperature conditions. Blood pressure as well as total and oxygenated hemoglobin levels decreased immediately after standing up and the ratio of blood pressure change when moving from a supine position to standing at high room temperature was the largest as compared with the other conditions. Total hemoglobin (Hb) volume was found to temporarily decrease after standing and required 22-24 sec to recover when the subject started from the sitting position and 33-36 sec when the subject started from the supine position. Cerebral oxygenation kinetics tended to be larger under high, rather than normal, temperature conditions. All COP parameters after standing were significantly larger in the high temperature condition than in the normal temperature condition. Body sway after standing was larger in the high temperature condition than in the normal temperature condition and after standing from a supine position than from a sitting position. In conclusion, cerebral oxygenation kinetics and blood pressure measured after the subject moved to the standing position changed dramatically under high temperature conditions, and variations in this parameter may influence body sway
The mobility performance of the elderly before, during and after crossing over an obstacle
Purpose. Tripping over objects is a major cause of fall-related injuries. The elderly feature decreased locomotor velocity with aging and delays in locomotion when encountering obstacles. Numerous studies have analyzed how the mobility performance of the elderly is affected when crossing over an obstacle. However, how is mobility performance affected when performing sequences of various locomotor movements (gait, changing direction, standing up and sitting down) that make up activities of daily living? To answer this question, this study investigated the changes in locomotor velocity when encountering an obstacle during various locomotor movements in both older adults and young adults by using the TUG, a representative mobility test. Methods. Thirty older adults who were judged to be able to walk independently by the Berg Balance Scale (BSS) (age: 70.0 ± 6.94 yrs; BB S: 54.7 ± 1.78 pts) and seventeen male young adults (age: 21.7 ± 2.37 yrs) participated in the "Timed Up & Go" (TUG) test with and without an obstacle. Using the TUG score (the total time required to complete the test), a rate of the total times (with an obstacle/ without an obstacle) was calculated to create an index of the decline in mobility performance by the obstacle. Results. The decline in the mobility performance of the elderly was significantly larger than the young adults for the following measurements: in the single stance phases just before and after an obstacle, the time needed to change direction 180 degrees, and for level walking after crossing over an obstacle. Conclusions. The elderly require a longer period of time for stepping over obstacles. Gait and the ability to change direction after encountering an obstacle was found to be slower when compared to the younger male population
Deprotonative metalation of five-membered aromatic heterocycles using mixed lithium-zinc species
International audienceDeprotonation of benzoxazole, benzothiazole, benzo[b]thiophene, benzo[b]furan, N-Boc protected indole and pyrrole, and N-phenylpyrazole using an in situ mixture of ZnCl2*TMEDA (0.5 equiv) and lithium 2,2,6,6-tetramethylpiperidide (1.5 equiv) in THF at room temperature was described. The reaction was evidenced by trapping with iodine, regioselectively giving the expected functionalized derivatives in 52 to 73% yields. A mixture of mono- and disubstituted derivatives was obtained starting from thiazole. Cross-coupling reactions of 2-metalated benzo[b]thiophene and benzo[b]furan with heteroaromatic chlorides proved possible under palladium catalysis. A reaction pathway where the lithium amide and zinc diamide present in solution behave synergically was proposed for the deprotonation reaction, taking account of NMR and DFT studies carried out on the basic mixture
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