Ameliorating effects of ethanol extract of root bark of Salacia nitida on blood electrolyte and renal perturbations in Plasmodium berghei-infected mice

Abstract Malaria, a disease of public health concern is a known cause of kidney failure, and dependence on herbal medicines for its treatment is increasing due to the high cost of drugs. So this study is designed to evaluate the ameliorating effect of ethanol extract from Salacia nitida root bark on electrolyte and renal perturbations in Plasmodium berghei-infected mice. Thirty malariainfected mice divided into five groups of six mice each and another group of six uninfected mice were used for the study. 280, 430, and 580 mg/kg of extract were given to infected mice in groups B, C, and D, 4 mg/kg of artesunate given to group E mice, and 4 ml/kg of physiological saline given to group A and uninfected group F mice for five days. Serum Na+, K+, HCO3, Cl-, TB, urea, creatinine, BUN concentrations, and BUN/creatinine ratio were determined using standard methods. Results showed significant increases (p < 0.05) in Na+, K+, and HCO3 and decreases in Cl-, TB, urea, creatinine, BUN, and BUN/creatinine ratio in the infected treated mice in groups B - E. This study showed that ethanol extract of S. nitida root bark is efficient in the treatment of renal disorders and blood electrolyte perturbations

Translocation of IGF-1R in endoplasmic reticulum enhances SERCA2 activity to trigger Ca2+ER perturbation in hepatocellular carcinoma

The well-known insulin-like growth factor 1 (IGF1)/IGF-1 receptor (IGF-1R) signaling pathway is overexpressed in many tumors, and is thus an attractive target for cancer treatment. However, results have often been disappointing due to crosstalk with other signals. Here, we report that IGF-1R signaling stimulates the growth of hepatocellular carcinoma (HCC) cells through the translocation of IGF-1R into the ER to enhance sarco-endoplasmic reticulum calcium ATPase 2 (SERCA2) activity. In response to ligand binding, IGF-1Rβ is translocated into the ER by β-arrestin2 (β-arr2). Mass spectrometry analysis identified SERCA2 as a target of ER IGF-1Rβ. SERCA2 activity is heavily dependent on the increase in ER IGF-1Rβ levels. ER IGF-1Rβ phosphorylates SERCA2 on Tyr990 to enhance its activity. Mutation of SERCA2-Tyr990 disrupted the interaction of ER IGF-1Rβ with SERCA2, and therefore ER IGF-1Rβ failed to promote SERCA2 activity. The enhancement of SERCA2 activity triggered Ca2+ER perturbation, leading to an increase in autophagy. Thapsigargin blocked the interaction between SERCA2 and ER IGF-1Rβ and therefore SERCA2 activity, resulting in inhibition of HCC growth. In conclusion, the translocation of IGF-1R into the ER triggers Ca2+ER perturbation by enhancing SERCA2 activity through phosphorylating Tyr990 in HCC.

Adaptive evolution of microorganisms based on industrial environmental perturbations / 生物工程学报

The development of synthetic biology has greatly promoted the construction of microbial cell factories, providing an important strategy for green and efficient chemical production. However, the bottleneck of poor tolerance to harsh industrial environments has become the key factor hampering the productivity of microbial cells. Adaptive evolution is an important method to domesticate microorganisms for a certain period by applying targeted selection pressure to obtain desired phenotypic or physiological properties that are adapted to a specific environment. Recently, with the development of technologies such as microfluidics, biosensors, and omics analysis, adaptive evolution has laid the foundation for efficient productivity of microbial cell factories. Herein, we discuss the key technologies of adaptive evolution and their important applications in improvement of environmental tolerance and production efficiency of microbial cell factories. Moreover, we looked forward to the prospects of adaptive evolution to realize industrial production by microbial cell factories.

Research progress on mechanical perturbation in stroke rehabilitation / 生物医学工程学杂志

Sensorimotor disorder can be easily caused by stroke, and there are many targeted movement rehabilitation therapies. With the development of rehabilitation robot technology, robot-assisted therapy combined with mechanical perturbations has become a more effective motor rehabilitation therapy. In this paper, the definition of mechanical perturbation and its physiological mechanism in stroke rehabilitation are introduced, the research progress on mechanical perturbation in the field of stroke rehabilitation therapy is mainly discussed, the application of mechanical perturbation in motor control, postural response and sensory evaluation of stroke rehabilitation is summarized, and the future development direction of mechanical perturbation rehabilitation therapy is also prospected.

Estructura poblacional del árbol Avicennia germinans (Acanthaceae) en un manglar alterado del Golfo de México / Population structure of Avicennia germinans trees (Acanthaceae) in a disturbed mangrove in the Gulf of Mexico

Resumen Introducción: Los manglares están en declive en el mundo, conocer su estructura y regeneración en diferentes niveles de alteración puede ayudar a comprender la dinámica poblacional ante situaciones de estrés. Objetivo: La meta principal del estudio fue analizar la estructura comunitaria y estimar la trayectoria de las poblaciones de Avicenia germinans en diferentes sitios de manglar que presentan tres niveles de alteración. Métodos: Ocho transectos de aproximadamente 500 m de largo y colocados de manera perpendicular a la laguna de Tampamachoco, Veracruz, interceptaron tres niveles de alteración en los sitios estudiados del bosque de manglar. En cada transecto, cuadrantes de 10 x 10 m, 5 x 5 m, y 1 x 1 m sirvieron para contar todos los árboles de mangle por especie y estadio de madurez en 2017 y 2018. Resultados: La especie más abundante fue: A. germinans seguida de Rhizophora mangle y Laguncularia racemosa. Con base en su abundancia, se encontraron diferencias significativas según los tres grados de alteración (AM R = 0.6, P < 0.001), ilustrado en un análisis de ordenación no métrico (nMDS). Una tabla de vida para A. germinans permitió un análisis poblacional que mostró una tasa intrínseca de incremento poblacional (r) negativa para los sitios que presentan alteración (-0.0027 u -0.0774) y positiva (0.0289) en el sitio sin alteración aparente. La supervivencia del estadio de plántula a juvenil varia de 50 % en el sitio no alterados a 5 y 4 % en los otros dos sitios. Conclusiones: Se necesitan medidas para incrementar la sobrevivencia de las plántulas y revertir la disminución de las trayectorias en los sitios con alteración, de otra forma el manglar tendrá una viabilidad reducida en el término medio.

Abstract Introduction: Globally, mangroves are declining; characterizing their structure and regeneration at different disturbance levels can help understand their responses to stressful situations. Objective: The study's primary goal was to analyze the mangrove community structure and to estimate the populations' trajectories of Avicenia germinans at different mangrove sites that present three levels of disturbance. Methods: Eight transects of approximately 500 m in length and laid perpendicular to the Tamapamchoco lagoon, Veracruz, intersected three levels of disturbance currently present on the mangrove forest. On each transect, 10 x 10 m, 5 x 5 m, and 1 x 1 m quadrants served to account for all mangrove trees by species and stage of maturity in 2017 and 2018. Results: The most abundant species was: A. germinans followed by Rhizophora mangle and Laguncularia racemosa. Based on their abundance, we found significant differences for the three levels of disturbance (ANOSIM R = 0.6, P < 0.001) presented in a non-metric ordination (nMDS). A life table for A. germinans allowed a population analysis that showed an intrinsic rate of population increase (r) that was negative at the disturbed sites (-0.0027 and -0.0774) and positive (0.0289) at the apparently undisturbed site. Seedling to juvenile stage survival ranged from 50 % at the undisturbed site to 5 and 4 % at the disturbed sites. Conclusions: Measures to increase the survival of seedlings are necessary to reverse the decreasing population trajectories at the disturbed sites; otherwise, the mangrove will have reduced viability in the medium term.

Prediction of drug-induced cell viability by SAE-XGBoost algorithm based on LINCS-L1000 perturbation signal / 生物工程学报

Different cell lines have different perturbation signals in response to specific compounds, and it is important to predict cell viability based on these perturbation signals and to uncover the drug sensitivity hidden underneath the phenotype. We developed an SAE-XGBoost cell viability prediction algorithm based on the LINCS-L1000 perturbation signal. By matching and screening three major dataset, LINCS-L1000, CTRP and Achilles, a stacked autoencoder deep neural network was used to extract the gene information. These information were combined with the RW-XGBoost algorithm to predict the cell viability under drug induction, and then to complete drug sensitivity inference on the NCI60 and CCLE datasets. The model achieved good results compared to other methods with a Pearson correlation coefficient of 0.85. It was further validated on an independent dataset, corresponding to a Pearson correlation coefficient of 0.68. The results indicate that the proposed method can help discover novel and effective anti-cancer drugs for precision medicine.

Efficacy Of Perturbation Training In Improving Balance And Function In The Management Of Knee Osteoarthritis

Background: Subjects who are suffering from osteoarthritis of the knee will have problems including progressive loss of function, depending on walking, climbing stairs, and it may affect lower extremity functions. Balance is a major component required for the activities of daily living and functions. The objective of the study was to compare the effectiveness of perturbation training and conventional physiotherapy in improving balance and function in the rehabilitation of knee osteoarthritis. Method: Study design was an experimental study. Thirty subjects (16 males and 14 females) suffering from knee osteoarthritis were randomized into a control group and experimental group. Fifteen subjects in the control group were treated with traditional methods like ultrasound, stretching and strengthening, and fifteen subjects in the experimental group were given perturbation training along with the conventional method. Outcome measures used were Timed get up and go test score (TUG) and Functional reach test score (FRT) scales, pre-assessed on Day 1. Each group received 14 sessions of treatment, after which post-assessment of outcome measures was done. Results: Timed get up and go test score was reduced in both groups after training, which was statistically significant (p<.05). The functional reach test score was increased after training in both groups, which was statistically significant (p<.05). However, comparing between groups, the experimental group showed more reduction in TUG score and improvement in the FRT score, which was statistically significant (p<.05). Conclusion: Perturbation training given with conventional treatment was found to have a significantly better effect in improving the function of the lower extremity in OA knee subjects. However, a well-designed trial, including a larger sample size with repeated measurements, is needed to find out the effectiveness of training with perturbation in the management of knee osteoarthritis and generalize it in a larger population.

Método de perturbación con transformada de Laplace para resolver problemas no lineales de múltiples soluciones, con condiciones a la frontera mixtas y Neumann / Laplace transform-perturbation method to solve nonlinear perturbative multiple solutions problems with mixed and Neumann boundary conditions

RESUMEN El campo de las ecuaciones diferenciales ha cobrado auge en la actualidad por el desarrollo científico y tecnológico. Por esta situación, el estudio de nuevas metodologías para solucionarlas se ha vuelto importante. A partir de la combinación del método de Laplace Transform (LT) y el método de perturbación (PM) este trabajo presenta el método LT-PM, y su motivación se encuentra en la aplicación conocida de la LT a ecuaciones diferenciales ordinarias lineales. El objetivo de este trabajo fue presentar una modificación del método de perturbación (PM), el método de perturbación con transformada de Laplace (LT-PM), con el fin de resolver problemas perturbativos no lineales, con condiciones a la frontera definidas en intervalos finitos. La metodología consistió en aplicar LT a la ecuación diferencial por resolver y después de asumir que la solución de la misma se puede expresar como una serie de potencias de un parámetro perturbativo, se obtiene la solución del problema aplicando sistemáticamente la transformada inversa de Laplace. Los principales resultados de este trabajo se muestran a partir de dos casos de estudio presentados, donde se observa que LT-PM es potencialmente útil para encontrar soluciones múltiples de problemas no lineales. Además, LT-PM mejora la aplicabilidad del método de perturbación en algunos casos de condiciones a la frontera mixtas y de Neumann, donde PM simplemente no funciona. Con el fin de verificar la exactitud de los resultados obtenidos, se calculó su error residual cuadrático (SRE), el cual resultó muy bajo, de donde se dedujo su precisión y la potencialidad de LT-PM. Se concluye que si bien el método propuesto resulta eficiente en los casos particulares presentados, se espera que sea una herramienta potencialmente eficiente y útil para otros casos de estudio, particularmente, en aquellos relacionados con aplicaciones prácticas en ciencias e ingeniería.

ABSTRACT The field of differential equations has recently gained attention due to recent developments in science and technology. For this reason, the analysis for the use of new methodologies to solve them has become important. Based on the combination of Laplace Transform method (LT) and Perturbation Method (PM) this article pro- poses the Laplace transform-Perturbation Method (LT-PM) which finds its motivation on the application of LT to linear ordinary differential equations. The goal of this work is to propose a modification of PM - the LT-PM), in order to solve nonlinear perturbative problems with boundary conditions defined on finite intervals. The proposed methodology consisted on the application of LT to the differential equation to solve and then, assuming that its solutions can be expressed as a series of perturbative parameter powers. Thus, the solution of the problem is obtained by systematically applying the transformed inverse LT. The main results of this paper were shown through two case studies, where LT-PM is identified as potentially useful for finding multiple solutions to nonlinear problems. Additionally, the LT-PM enhances the applicability of PM, in some cases of mixed and Neumann boundary conditions, where PM is unsuitable to provide the results. With the purpose of verifying the accuracy of the obtained results, the Square Residual Error (SRE) was calculated. The resulting value was extremely low, which showed the precision and potential of LT-PM. We conclude that, although the proposed method resulted efficient for the case studies presented in this article, it is expected that LT-PM can be a potentially useful tool for other case studies. Particularly those related to the practical applications of science and engineering.

A Monte Carlo study on dose perturbation due to dental restorations in a 15 MV photon beam

Aim: The main purpose of this study is to evaluate the effect of dose perturbation due to common dental restoration materials in the head and neck radiotherapy with a 15 MV external photon beam. Setting and Design: Teeth with three dental restorations such as tooth filled with Amalgam, Ni-Cr alloy, and Ceramco were simulated by MCNPX Monte Carlo code. In this simulation, the dental materials were exposed by a 15 MV photon beam from a Siemens Primus linac, inside a water phantom. Materials and Methods: A Siemens Primus linear accelerator and a phantom including: tooth only, tooth with Amalgam, tooth with Ni-Cr alloy, and tooth with Ceramco were simulated by MCNPX Monte Carlo code, separately. The percentage dose change was evaluated relative to dose in water versus depth for these samples on the beam's central axis. The absolute dose by prescription of 100 cGy dose in water phantom at 3.0 cm depth was calculated for water, tooth, tooth with Amalgam, tooth with Ni-Cr alloy, and tooth with Ceramco. Results: The maximum percentage dose change is related to tooth with Ni-Cr alloy, tooth, tooth with Ceramco, and tooth with Amalgam with amounts of 7.73%, 6.95%, 4.7%, and 3.06% relative to water at 0.75 cm depth, respectively. When 100.0 cGy dose was prescribed at 3.1 cm, the maximum absolute dose was 201.0% in the presence of tooth with Ni-Cr alloy at 0.75 cm. Conclusion: Introduction of the compositions of dental restorations can improve the accuracy of dosimetric calculations in treatment planning and protect the healthy tissues surrounding teeth from a considerable overdose

Effects of Transcranial Alternating Current Stimulation on Serial Reaction Time Task / 中国康复理论与实践

Objective:To investigate the effects of transcranial alternating current stimulation (tACS) on electroencephalography (EEG) rhythm and cognitive function. Methods:In December, 2017, 60 healthy young volunteers were divided into four groups equally, who accepted 20 Hz real or sham tACS on left C3 or right C4. They were asked to complete four types of finger sequence key pressing tasks (left/right hand random/regular key pressing) before and after stimulation, while the EEG signals were collected and the reaction time and accuracy were observed. EEG signals were analyzed with multiple difference analysis of event-related spectral perturbation. Results:The reaction time of contralateral hand reduced after C4 real stimulation. Conclusion:Right 20 Hz tACS can improve the learning of contralateral limb sequential movement.

Regulation and adaptive evolution of industrial microorganisms towards genetic and environmental disturbances / 生物工程学报

Harnessing industrial microorganisms to utilize renewable feedstocks and meanwhile produce biofuels, bulk chemicals, food ingredients, nutraceuticals, pharmaceuticals, industrial enzymes, etc. is the basis for successful biological industries. Robust traits of industrial microorganisms including high yield and productivity as well as stress tolerance are controlled by sophisticated genetic regulatory networks. Engineering robustness of industrial microorganisms requires systematic and global perturbations at the genome-wide scale to accelerate the accumulation of diversified genotypic mutations, thus generating desirable phenotypes. We review heve the mechanisms of genetic regulation and stress response in robust industrial organisms, the global perturbations and multiplex accelerated evolution at the genome-wide scale, as well as the global perturbation of cellular redox balance. In the future, based on system biology and synthetic biology, more efforts should be further devoted to understanding the mechanisms behind robust traits in industrial microorganisms under industrial niches for modeling and prediction as well as systematic engineering.

Trends and gaps of the scientific literature about the effects of fire on Brazilian Cerrado / Tendências e lacunas na literatura científica sobre os efeitos do fogo no Cerrado Brasileiro

Abstract Fire management is an important issue in the Brazilian Cerrado, since both anthropogenic high intensity fires and complete fire suppression can reduce the biodiversity in this biome. In this paper, we highlight the trends in scientific literature about fire effects in the Cerrado, aiming to detect possible gaps and to indicate directions of future scientific research. We searched for articles in the periodic database Web of Knowledge from 1991 to 2016, and observed an increase in the number of publications throughout the years. Most articles were associated with Brazilian institutions (58%), followed by those with collaboration between Brazilian and international institutions (33%), and those published by authors exclusively from international institutions (9%). Most articles addressed the effects of fire on biodiversity (77%), followed by articles about abiotic environment (19%), and then biotic interactions or interactions between organisms and environment (4%). The most studied taxonomic group was plants (75%), followed by mammals (8%) and insects (6%), with the remaining taxa comprising about 11% of publications. The Federal District was the federative unit with the greatest number of studies (31%). The majority of studies was conducted in areas with fewer fire events, whereas areas with major incidence of fires are poorly studied. Our data shows that studies on the effect of fires on the Brazilian Cerrado are geographically and taxonomically biased. This lack of knowledge limits the extrapolations about the effects of fire on this biome. Therefore, we emphasize the need for investment in research in areas with high fire frequency and also for an increase in knowledge about these effects on the biota, especially on the fauna. This action is fundamental to support the development of public policies for effective and directed fire management in the Cerrado.

Resumo O manejo do fogo é uma questão importante no Cerrado brasileiro, pois tanto os incêndios antropogênicos de alta intensidade, quanto a sua supressão completa podem reduzir a biodiversidade neste bioma. Neste artigo, destacamos as tendências na literatura científica sobre os efeitos do fogo no Cerrado, com o objetivo de detectar possíveis lacunas e indicar direções de futuras pesquisas científicas. Buscamos artigos na base de periódicos Web of Knowledge no período de 1991 a 2016, e observamos um aumento no número de publicações ao longo dos anos. A maioria dos artigos foi associada a instituições brasileiras (58%), seguidos por colaborações entre instituições brasileiras e internacionais (33%) e publicações de autores exclusivamente de instituições internacionais (9%). A maioria dos artigos abordou os efeitos do fogo na biodiversidade (77%), seguido de artigos sobre o ambiente abiótico (19%), e interações bióticas ou interações entre organismos e o ambiente (4%). O grupo taxonômico mais estudado foi plantas (75%), seguido de mamíferos (8%) e insetos (6%). Os táxons restantes incluem 11% das publicações. O Distrito Federal foi a unidade federativa com o maior número de estudos (31%). A maioria dos estudos foi realizada em áreas com menos queimadas, enquanto as áreas com maior incidência de fogo são mal estudadas. Nossos dados mostram que os estudos sobre o efeito do fogo no Cerrado brasileiro são enviesados do ponto de vista geográfico e taxonômico. Esta falta de conhecimento limita as extrapolações sobre o efeito do fogo neste bioma. Portanto, enfatizamos a necessidade de investimentos para pesquisas em áreas com alta freqüência de queimadas e a necessidade em aumentar o conhecimento sobre estes efeitos na biota, especialmente na fauna. Esta ação é fundamental para apoiar o desenvolvimento de políticas públicas para uma gestão efetiva e direcionada do fogo no Cerrado.

Evaluation by damped least-square algorithm on target identification ability of intracranial focal bidirectional electrical impedance perturbation / 医疗卫生装备

Objective To evaluate the effect of damped least-square algorithm on the identification of focal bidirectional electrical impedance perturbation in the intracranial area, and to analyze the influence of this kind of perturbation on the reconstruction quality of electrical impedance tomography. Methods Focal bidirectional electrical impedance perturbation was built based on the three-dimensional model and damped least-square algorithm was introduced into imaging. The position error and resolution were used to evaluate the imaging performance.Results When the focal electrical impedance perturbation existed,the target whose conductivity varied greatly or volume was large was more likely to be identified in the images while the target with smaller volume or variable conductivity presented in the reconstruction image was not obvious. It's pointed out that it may cause reconstruction images in some cases could not truly reflect the location and change information of the object of primary cerebral hemorrhage.At the same time,it affected the reconstruction precision,causing the position error and resolution with large fluctuation. Conclusion In reconstruction algorithm linearity correct matrix introduced for bidirectional electrical impedance perturbation contributes to enhancing the recognition of bidirectional perturbation, so that the characterization of the electrical impedance imaging can be augmented for clinical intracerebral hemorrhage.

Comparison of the effects of two methods in the treatment of urinary incontinence after transurethral resection of prostate / 中国基层医药

Objective To compare the effects of ball of urethra suspension with Yiqi perturbation urine and subtract two methods in the treatment of urinary incontinence after transurethral resection of prostate. Methods From February 2012 to February 2017,60 patients with urinary incontinence after transurethral resection of prostate in the Third People's Hospital of Shuozhou were selected. According to different therapeutic methods,the patients were divid-ed into two groups,with 30 cases in each group. The control group was treated with ball of urethra suspension,the observation group was given Yiqi perturbation for urine. The incidence of urinary incontinence and degree of the two groups after treatment were observed. The incontinence duration,international prostate symptom score,residual urine volume,maximum urine flow rate and patients' quality of life scores were compared between the two groups. Results After treatment,the incidence rate of urinary incontinence in the observation group was 8. 3％ ,which was significantly lower than 23. 3％ in the control group (χ2 = 10. 28,P < 0. 05). The incontinence duration,international prostate symptom score,residual urine volume,maximum urinary flow rate in the observation group were (7. 6 ± 2. 1) d, (21. 2 ± 3. 4)points,(119. 5 ± 60. 4)mL,(4. 1 ± 1. 3)mL/ s,respectively,which were better than those in the control group [(15. 8 ± 3. 2)d,(5. 6 ± 1. 5)points,(19. 7 ± 6. 9)mL and (20. 4 ± 5. 3)mL/ s],the differences between the two groups were statistically significant (t = 11. 73,22. 99,8. 99,22. 99,all P < 0. 05). The quality of life scores in the observation group were better than those in the control group (all P < 0. 05). Conclusion Yiqi perturbation urine for urinary incontinence caused by transurethral resection of benign prostatic hyperplasia is better than the ball of urethra suspension,it can reduce the degree of postoperative incontinence,improve patients' quality of life.

The Effect of the Base of Support on Anticipatory Postural Adjustment and Postural Stability

PURPOSE: This study was to identify the anticipatory postural adjustment (APA) mechanism which is represented by the onset time of trunk muscles and the displacement of the center of pressure (COP) according to the different base of support (BOS) during upper extremity movement. METHODS: Thirty healthy subjects (14 males, 16 females) participated in this study. The movement was performed for 10 trials during each of various BOS (shoulder - width double leg stance, narrow base double leg stance, tandem stance, non-dominant single leg stance) at the 1.2 Hz frequency. Electromyography was used to measure muscle onset time and biorescue was used to measure characteristics of the displacement of COP. Surface bipolar electrodes were applied over the right deltoid anterior, right latissimus dorsi, both rectus abdominis, both internal oblique and both erector spinae. The data were analyzed by repeated one-way ANOVA and Duncan's post hoc test. RESULTS: The study has revealed following. There were significant differences with muscle onset time in each BOS (p<0.01). There were significant differences in characteristics of the COP in each BOS (p<0.01). CONCLUSION: The study found that the more narrowed the basis requires the more rapid anticipatory postural control in contralateral postural muscle when the upper extremity movement is performed.

Inspiratory and Expiratory Resistances During Exercise.

Aims: Paradoxical vocal fold motion, especially during exercise, causes symptoms of dyspnea in patients experiencing this condition. At present, the standard means to diagnose this condition is invasive using a laryngoscope. The Airflow Perturbation Device (APD) could offer a simpler means of diagnosis and monitoring, but the APD must be validated with laryngoscopy. Both devices require access to the mouth, and so cannot be used simultaneously. The aim of this study was to determine if respiratory resistance of exercising subjects changes immediately after exercise begins and ends. Study Design: The study was conducted as a prospective study. Place and Duration of Study: All tests were conducted in the Human Performance Laboratory, Fischell Department of Bioengineering, University of Maryland, College Park, MD between August 2011 and August 2012. Methodology: Fifteen subjects exercised on a bicycle ergometer at 70% of maximum predicted heart rate while breathing through the APD. Results: Results show that APD measurements made just prior and after the cessation of exercise are comparable. Conclusion: APD measured inspiration and expiration resistances do not change immediately after exercise cessation.

Influence of aging on neuromuscular reaction during lateral perturbation / 医用生物力学

Objective To provide theoretical reference for the research on lateral postural control in older people by using the electromyography （EMG）technique to compare the neuromuscular reaction between the young and older people during lateral perturbation. Methods Postural reactions of 14 young people and 14 older people as subjects were evoked by sudden unpredictable medio lateral translation platform. The surface EMG data were collected from peroneus longus, anterior tibialis, gluteus medius and erector spinae of the left side of the body. Results The latencies in anterior tibialis, gluteus medius and erector spinae were obviously delayed in older people, and the duration of time to peak in peroneus longus, anterior tibialis and gluteus medius of older people was much longer than that of young people. Conclusions The delayed response of ankle, hip and trunk muscle and the low efficacy of contraction rate in ankle and hip muscles to the unexpected perturbation might be the primary reason for the decrease of lateral postural control in older people.

Propagation of nonlinear pressure wave in artery vessels / 医用生物力学

Objective The mechanical model of nonlinear blood flow in large blood vessels is developed and the propagation of nonlinear pressure wave is studied. Methods Taking the effect of large deformation, nonlinear equation of motion is established in the current configuration in terms of the constitutive equations proposed by demiray for soft biological tissues. Results Employing the reductive perturbation method the KdV equation is derived from the nonlinear partial equations governing the motion of coupled system. Conclusion It is shown from this that the system admits an accurate periodic wave solution or solitary wave solution under certain conditions.

Propagation of nonlinear pressure wave in artery vessels / 医用生物力学

Objective The mechanical model of nonlinear blood flow in large blood vessels is developed and the propagation of nonlinear pressure wave is studied.Methods Taking the effect of large deformation,nonlinear equation of motion was established in the current configuration in terms of the constitutive equations proposed by Demiray for soft biological tissues.Resuit Employing the reductive perturbation method the KdV equation is derived from the nonlinear partial equations governing the motion of coupled system.Conclusions It is shown from this study that the system may have an accurate periodic wave solution or solitary wave solution under certain conditions.

Propagation of nonlinear pressure wave in artery vessels / 医用生物力学

Objective The mechanical model of nonlinear blood flow in large blood vessels is developed and the propagation of nonlinear pressure wave is studied.Methods Taking the effect of large deformation,nonlinear equation of motion was established in the current configuration in terms of the constitutive equations proposed by Demiray for soft biological tissues.Resuit Employing the reductive perturbation method the KdV equation is derived from the nonlinear partial equations governing the motion of coupled system.Conclusions It is shown from this study that the system may have an accurate periodic wave solution or solitary wave solution under certain conditions.