Search results for "Explosive"

Luminescent CdSe Quantum Dot Arrays for Rapid Sensing of Explosive Taggants

2022

Chemical sensors based on fluorescent quantum dots have attracted intense interest because of their excellent optical and electronic properties compared to the routinely employed fluorescent organic dyes. This study reports a CdSe QD-polymer-based luminescent chemosensor, which is based on an array containing either green-emitting or red-emitting CdSe QDs embedded in polycaprolactone as a polymer host matrix. We evaluate the sensing capability of the nanocomposites by exposing both sensors to vapors of explosive taggants, explosive-like molecules, and some common solvents. Both nanocomposites exhibit a very fast response time of <30 s. The limit of detection of the sensors for 3-nitrotoluen…

Muscle cross-sectional area, force production and relaxation characteristics in women at different ages

1991

Thirty women, divided among three different age groups, i.e. 30 years (range 26–35;n = 10), 50 years (range 46–55;n = 10) and 70 years (range 66–75;n = 10) volunteered as subjects for examination of the characteristics of the muscle cross-sectional area (CSA), maximal voluntary isometric force, isometric force-time and relaxation-time of their leg extensor muscles. The CSA of the quadriceps femoris muscle in the youngest age group was slightly larger (NS) than in the middle-aged group and much larger (P<0.41) than in the oldest age group whose CSA was markedly smaller (P<0.01) than the middle-aged group. Maximal force in the youngest group was slightly greater (NS) than in the middle-aged g…

Myopia, the challenge of Ophthalmology and its worldwide “explosive epidemic”

2018

Neuromuscular responses to explosive and heavy resistance loading

2000

The EMG power spectrum may shift towards higher frequencies with higher movement velocities. Fatigue, on the other hand, can cause a decrease in the frequency components. The purpose of this study was to examine acute effects of explosive (EE) and heavy resistance (HRE) concentric leg press exercise on muscle force, EMG and blood lactate. The EE included five sets of ten repetitions with 40+/-6% of the isometric maximum at a 100 degrees knee angle performed as explosively as possible. The same number of repetitions was performed in HRE but with a heavier load (67+/-7% of the isometric maximum at a 100 degrees knee angle). Maximal isometric and single concentric actions of different loads, a…

Effects of Sparring Load on Reaction Speed and Punch Force During the Precompetition and Competition Periods in Boxing.

2017

Seven, male, national-level boxers (age, 20.3 ± 2.7 years; height, 1.80 ± 0.06 m; mass, 73.8 ± 11.1 kg) participated in this study to investigate the effects of sparring on reaction time and punch force of straight punches measured during the precompetition and competition periods. Heart rate and blood lactate concentrations were also monitored. Sparring load was chosen in accordance with the current rules: 3 × 3-minute bouts with 1-minute break in between. Reaction time of rear straight lengthened (p < 0.01) during the sparring load of the precompetition period after the third round (to 390 milliseconds) in comparison to the competition period (to 310 milliseconds). Reaction time of lead s…

Maximal and explosive force production capacity and balance performance in men of different ages

1999

A group of 32 healthy men (M) divided into three different age groups, i.e. M20 years [mean 21 (SD 1); n = 12], M40 [mean 40 (SD 2); n = 10] and M70 [mean 71 (SD 5); n = 10] volunteered as subjects for examination of maximal and explosive force production of leg extensor muscles in both isometric and dynamic actions (squat jump, SJ and counter movement jump, CMJ, and standing long-jump, SLJ). The balance test was performed on a force platform in both isometric and dynamic actions. Maximal bilateral isometric force value in M70 was lower (P < 0.001) than in M40 and as much as 46% lower (P < 0.001) than that recorded in M20 (P < 0.001). The maximal rate of force development (RFD) on the force…

Maximal force, force/time and activation/coactivation characteristics of the neck muscles in extension and flexion in healthy men and women at differ…

2002

This study examined the force production characteristics, activation/coactivation and endurance capacity of the neck extension and flexion muscles in healthy men (n=29) and women (n=28) divided into three age groups (18–26 years, 30–37 years and 45–55 years). Force and electromyography (EMG) measurements were performed during the maximal voluntary isometric extension and flexion actions. This was followed by an endurance test (ET; 60% force level of maximal voluntary contraction sustained until exhaustion), after which the force and EMG recordings were repeated. Men were both stronger and had higher values (P<0.001) for explosive force (rate of force development, RFD) than women in both act…

Exposure to nitroaromatic explosives and health effects during disposal of military waste.

2003

To investigate the exposure to dinitrotoluene (DNT) and trinitrotoluene (TNT) and the resulting effects in workers which occur during the disposal of military waste.Eighty two employees from a mechanical plant in Germany were studied, of whom 51 were regularly exposed to ammunition containing TNT and DNT, 19 occasionally, and 12 not at all.Air analyses yielded maximum concentrations of 20 micro g/m(3) for 2,4-DNT and 3250 micro g/m(3) for 2,4,6-TNT, respectively. The maximum concentrations in the urine of workers regularly exposed amounted to 5.0 micro g/l of 2,4,6-TNT, 1464.0 micro g/l of 2-amino-4,6-dinitrotoluene, 6693.0 of micro g/l 4-amino-2,6-dinitrotoluene, 2.1 micro g/l of 2,4-DNT, …

Effects of Combined Strength and Sprint Training on Lean Mass, Strength, Power and Sprint Performance in Masters Road Cyclists

2017

Del Vecchio, L, Stanton, R, Reaburn, P, Macgregor, C, Meerkin, J, Villegas, J, and Korhonen, MT. Effects of combined strength and sprint training on lean mass, strength, power, and sprint performance in masters road cyclists. J Strength Cond Res 33(1): 66-79, 2019-Strength and sprint-training exercises are integral part of training in many younger endurance cyclists to improve cycling efficiency and sprinting ability. This study was undertaken to examine whether muscle and performance characteristics could be improved in endurance-trained masters cyclist by adding strength and sprint-training stimuli into their training regimen. Twenty-five masters road cyclists were assigned to a combined …

Effects of a 12-week strength training program on experimented fencers' movement time.

2014

The purpose of this study was to determine the effects of a 12-week strength training program on movement time (MT) on fencers of national level. Twelve male fencers were randomly divided into 2 groups: the control group (CG: N = 6; age, 22.3 ± 8.1 years) and the treatment group (TG: N = 6; age, 24.8 ± 7.2 years). The CG fencers followed the standard physical conditioning program, which was partially modified for the TG. The TG participated in a 12-week strength training program divided into 2 parts: maximal strength training, including weightlifting exercises (2 days a week for 6 weeks) and explosive strength training, with combined weights and plyometric exercises (2 days a week for 6 wee…