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Author(s):  
Валерий Иванович Иванов ◽  
Сергей Анатольевич Пячин

На основе стационарного решения уравнения диффузии изучена сепарация наночастиц в прозрачной полидисперсной водной суспензии с различными типами распределений по размерам под действием силы светового давления, возникающей в поле лазерного излучения интенсивностью 0,5 - 500 кВт/см. Установлено, что на дно кюветы преимущественно будут осаждаться частицы радиусом более 100 нм, а концентрация более мелких наночастиц во всем объеме суспензии останется без изменений. В случае симметричного начальное распределения наночастиц по размерам воздействие интенсивного светового пучка на суспензию приводит к нарушению симметрии кривой функции распределения, а также смещению максимума в область меньших размеров частиц на облучаемой поверхности. Если начальное распределение по размерам имеет несимметричный характер, исходное одномодовое распределение частиц по размерам трансформируется в двумодовое. Данная методика может быть использована для выделения наночастиц определенных размеров в зависимости от плотности мощности излучения. On the basis of a stationary solution of a diffusion equation separation of nanoparticles in a transparent polydisperse aqueous suspension with different types of size distributions was studied under the action of the light pressure arising in the laser radiation field with the intensity of 0,5 - 500 kW/cm. It was found that particles with a radius of more than 100 nm will mainly be precipitated at the bottom of the cell, and the concentration of smaller nanoparticles in the entire volume of the suspension will remain unchanged. In the case of a symmetrical initial distribution of nanoparticles size, the effect of a light beam with high intensity on the suspension leads to a violation of the symmetry of the distribution function curve, as well as a shift of the maximum to the region of smaller particle sizes on the irradiated surface. If the initial size distribution is asymmetric, the initial single-mode particle size distribution is transformed into a two-mode one. This technique can be used to isolate nanoparticles of certain sizes depending on the power density of the radiation.


Author(s):  
Wen-Chieh Yang ◽  
Che-Hsiu Chen ◽  
Lee-Ping Chu ◽  
Chih-Hui Chiu ◽  
Chin-Hsien Hsu ◽  
...  

Vibration foam rolling (VR) can improve flexibility and sports performance. However, blood pressure (BP), heart rate (HR) and senior fitness test (SFT) responses induced by an acute VR session in older women are currently unknown. Fifteen healthy women (72.90 ± 4.32 years) completed three separated randomly sequenced experimental visits. During each visit, they started with a warm-up protocol (general warm up (GW): walking + static stretching (SS), SS + VR with light pressure (VRL), or SS + VR with moderate pressure (VRM)), and completed BP, HR, SFT measurements. The systolic BP increased significantly after all three warm up protocols (p < 0.05). Both VRL and VRM protocols induced statistically significant improvements (effect size range: 0.3–1.04, p < 0.05) in the senior fitness test (back scratch, 30 s chair stand, 30 s arm curl, and 8 foot up and go), as compared to the GW. In addition, the VRM showed greater improvement for the 2 min step test when comparing with the VRL. Therefore, including VR in a warm-up protocol can result in superior SFT performance enhancement than the GW does in healthy older women.


2021 ◽  
Author(s):  
Ha Young Lee ◽  
Min Sub Kwak ◽  
Kyung-Won Lim ◽  
Hyung Soo Ahn ◽  
Geon-Tae Hwang ◽  
...  

2021 ◽  
Vol 9 (2) ◽  
pp. 193-201
Author(s):  
Riza Galih Mustika Rini ◽  
Eddy Purnomo

This study aims to improve the athlete's performance from the physiological aspect by knowing the differences in the response of sport massage and swedish massage with variations in pressure (light, medium, and heavy) on the hind limbs a 30 m running speed taken four times. This research is a quasi-experimental design, with the research subjects of POPDA Sleman athletic athletes with sample of 20 people. The sample was divided by matching pairs with the aim of both groups getting a balanced power. The treatments used are sports massage with movement manipulation (effleurage, tapotement, shaking/vibration) and swedish massage with movement manipulation (drainage, compression, tapotement, shaking/vibration) with pressure variation. The results showed that there were differences in the effect/good response of the type of sports massage treatment (group x) with moderate pressure. This is evidenced by the results of an increase in record time by an average of 0.36 seconds. Treatment of light pressure increased record time by an average of 0.28 seconds. Heavy pressure treatment increased record time by an average of 0.04 seconds. There is a difference in the effect/unfavorable response of the type of swedih massage treatment (group y) with all types of pressure, because it provides a decreased response time from pretest to posttest. It is proven by the decrease in the average time of 0.16 seconds on the light pressure treatment, the decrease in the average time of 0.24 seconds on the medium pressure treatment, and a decrease of 0.34 seconds on the heavy pressure treatment.


2021 ◽  
Vol 1 (1) ◽  
pp. 3-31
Author(s):  
Swathi Ippili ◽  
Venkatraju Jella ◽  
Alphi Maria Thomas ◽  
Soon-Gil Yoon

Sensors have recently gathered significant attention owing to the rapid growth of the Internet of Things (IoT) technology for the real-time monitoring of surroundings and human activities. Particularly, recently discovered nanogenerator-based self-powered sensors are potential candidates to overcome the existing problems of the conventional sensors, including regular monitoring, lifetime of a power unit, and portability. Halide perovskites (HPs), with an excellent photoactive nature, dielectric, piezoelectric, ferroelectric, and pyroelectric properties, have been potential candidates for obtaining flexible and self-powered sensors including light, pressure, and temperature. Additionally, the photo-stimulated dielectric, piezoelectric, and triboelectric properties of HPs make them efficient entrants for developing bimodal and multimode sensors to sense multi-physical signals individually or simultaneously. Therefore, we provide an update on the recent progress in self-powered sensors based on pyroelectric, piezoelectric, and triboelectric effects of HP materials. First, the detailed working mechanism of HP-based piezoelectric, triboelectric, and pyroelectric nanogenerators—operated as self-powered sensors—is presented. Additionally, the effect of light on piezoelectric and triboelectric effects of HPs, which is indispensable in multimode sensor application, is also systematically discussed. Furthermore, the recent advances in nanogenerator-based self-powered bimodal sensors comprising HPs as light-active materials are summarized. Finally, the perspectives and continuing challenges of HP-based self-powered sensors are presented with some opportunities for future development in self-powered multimode sensors.


Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 351
Author(s):  
Yannick Fleury

The range of environmental conditions in marine life is tremendous at different physico-chemical criteria (temperature, light, pressure and salinity) [...]


2021 ◽  
Author(s):  
Davide D Ambrosio ◽  
Marialuisa Capezzuto ◽  
Saverio Avino ◽  
Pietro Malara ◽  
Antonio Giorgini ◽  
...  
Keyword(s):  

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Musa S. Danazumi ◽  
Abdulsalam M. Yakasai ◽  
Aminu A. Ibrahim ◽  
Usman T. Shehu ◽  
Shehu U. Ibrahim

Abstract Context Studies have indicated that the muscle energy technique (MET) and the positional release technique (PRT) are effective in the management of piriformis syndrome (PS); however, evidence is scarce regarding the combination of these techniques in the form of an integrated neuromuscular inhibition technique (INIT) in the management of individuals with PS. Although a previous trial investigated the effect of INIT for PS, that study did not integrate Ruddy’s reciprocal antagonist facilitation (RRAF) method into the INIT protocol, nor did the authors diagnose PS according to established criteria. Objectives To examine the effects of INIT with integrated RRAF compared with PRT in the management of patients diagnosed with PS. Methods This study was designed as a single blind randomized clinical trial in which participants diagnosed with PS were randomly allocated into INIT and PRT groups. Each group attended two treatment sessions per week for 8 weeks. Patients in the INIT group received a protocol in which the patient’s tender point or trigger point was palpated in the belly of the piriformis approximately halfway between the inferior lateral angle of the sacrum and the greater trochanter, at which point the therapist applied an intermittent or sustained pressure and maintained the pressure for 20–60 seconds (depending on the participant’s response to pain reduction). For INIT patients, that protocol was also followed by RRAF, a method in which a patient introduces a series of tiny/miniature contractions or efforts (20 times per 10 seconds) against a therapist’s resistance. Patients in the PRT group were treated by palpating the same trigger point described in the INIT group, followed by application of light pressure at the location of the trigger point, which was maintained the pressure for 2 minutes or until the pain subsided (determined by asking the participant to report a pain score using a visual analog scale at 30 second intervals). For both groups, three repetitions of the INIT or PRT treatment were performed over 10 minutes at each clinical visit. Additionally, each group also received stretching exercises immediately after the INIT or PRT treatment session. Each participant was assessed at baseline, immediately posttreatment, and at 4 months posttreatment for pain, sciatica, functional mobility, quality of life, hip abduction, and internal rotation. A repeated measures analysis of variance (ANOVA) of within-between group interactions was used to analyze the treatment effect. Results Forty eight participants (age range, 25–47 years; mean age ± standard deviation, 32.81 ± 3.27 years) were randomized into the INIT and PRT groups, with 24 participants in each group. No significant between-group differences (p>0.05) were observed in the baseline demographic and clinical variables of the participants. A repeated-measures ANOVA indicated that there was a significant time effect for all outcomes, with a significant interaction between time and intervention (p<0.001). The Bonferroni post hoc analyses of time and intervention effects indicated that the INIT group improved significantly compared with the PRT group in all outcomes (p<0.05) immediately posttreatment and at the 4 months follow up period. Conclusions INIT was more effective than PRT in the management of individuals with PS. It should be noted the significant improvement achieved in both the groups may have also been contributed to by the stretching exercises that were used as adjunct therapies by both groups.


2021 ◽  
Vol 136 (5) ◽  
Author(s):  
Andrea Macchi ◽  
Onofrio M. Maragò
Keyword(s):  

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