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To detect the expression characteristic of circ_0006948 in bladder cancer (BC), and to analyze its relationship with pathological parameters and prognosis in BC patients. In addition, molecular mechanisms of circ_0006948 on driving the malignant progression of BC by activating epithelial-mesenchymal transition (EMT) was explored.Circ_0006948 levels in 72 BC and paracancerous tissues were detected, and their relationship with pathological parameters and prognosis in BC patients was analyzed by chi-square test. After establishing circ_0006948 knockdown model in 253j and T24 cells, phenotype changes were assessed by cell counting kit-8 (CCK-8), transwell and wound healing assay. Regulatory effects of circ_0006948 on EMT-associated gene expressions in BC cells were determined by Western blot. Finally, the interaction between circ_0006948 and N-cadherin was evaluated by rescue experiments.Circ_0006948 was upregulated in BC tissues and cell lines. High level of circ_0006948 indicated advanced tumor stage, high rates of lymph node metastasis and distant metastasis, and poor prognosis in BC. Knockdown of circ_0006948 reduced proliferative and metastatic abilities in BC cells. The key protein in the EMT signaling E-cadherin was upregulated by knockdown of circ_0006948 in BC cells, while N-cadherin, Vimentin, β-catenin and MMP-9 were downregulated. The interaction between circ_0006948 and N-cadherin was identified, and they were co-responsible for the malignant development of BC.Circ_0006948 is upregulated in BC samples, and it is closely linked to tumor stage, metastasis and prognosis in BC patients. It drives proliferative and metastatic abilities in BC cells by activating EMT.

Background and Purpose— Stroke disability is a major health burden in rural China where rehabilitation services are inadequate. We aimed to determine the effectiveness of a novel nurse-led, caregiver-delivered model of stroke rehabilitation in rural China. Methods— A multicenter prospective, randomized open, blinded outcome assessed, controlled trial was conducted in 3 rural county hospitals in China: Zhangwu, Liaoning Province (Northeast); Qingtongxia, Ningxia Hui Autonomous Region (Northwest); and Dianjiang, Chongqing Municipality (Southwest). Adult patients (age 18–79 years) with residual disability (Barthel Index score ≤80/100) after a recent acute stroke were randomized to a new service model or usual care. The new intervention was multifaceted and was based on a task-shifting / training-the-trainers model, supported by a custom-designed smartphone application, where patients and caregivers received evidence-based in-hospital education and stroke rehabilitation training (focus on mobility, self-care, and toileting), delivered by trained nurses before hospital discharge, and 3 postdischarge support telephone calls. Outcome assessments were undertaken before hospital discharge and at 3 and 6 months. Primary outcome was physical functioning (Barthel Index scores) at 6 months, assessed by research staff blind to treatment allocation, adjusted for baseline covariates in an intention-to-treat analysis. Secondary outcomes included measures of mobility, health-related quality of life, mood, and caregiver burden. The study included a process evaluation that assessed intervention fidelity. Results— From November 2014 to December 2016, 246 stroke patients were randomized to intervention (n=118) or control (n=128) groups. There was no statistically significant difference in adjusted 6-month Barthel Index scores between groups (70.1 versus 74.1, mean difference, −4.0 [95% CI, −10.0 to 2.9]), nor any differences across the other outcome measures. Process evaluation interviews revealed that the intervention was desirable and positively accepted by nurses, caregivers, and patients but was considered too complex despite efforts to simplify materials for the rural context. Key strategies identified for future studies included the use of community health workers, smartphone application enhancement, and simpler and more frequent training for nurses, caregivers, and patients. Conclusions— A novel nurse-led, digital supported, caregiver-delivered stroke rehabilitation program did not improve patient physical functioning after stroke in rural China. Further stroke rehabilitation research suitable for resource-poor settings is required, with several components being suggested through stakeholder interviews in our study. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT02247921.

SummaryUsing wearable robots is an effective means of rehabilitation for stroke survivors, and effective recognition of human motion intentions is a key premise in controlling wearable robots. In this paper, we propose an inertial measurement unit (IMU)-based gait phase detection system. The system consists of two IMUs that are tied on the thigh and on the shank, respectively, for collecting acceleration and angular velocity. Features were extracted using a sliding window of 150 ms in length, which was then fed into a quadratic discriminant analysis (QDA) classifier for classification. We recruited five stroke survivors to test our system. They walked at their own preferred speed on the level ground. Experimental results show that our proposed system has the ability of recognizing the gait phase of stroke survivors. All recognition accuracy results are above 96.5%, and detections are about 5–15 ms in advance of time. In addition, using only one IMU can also give reliable recognition results. This paper proposes an idea about the further research on human–computer interaction for the control of wearable robots.

Date Presented 04/01/2022 This study provides evidence for the validity of the Weekly Calendar Planning Activity-10 (WCPA-10) for adults with stroke. The WCPA-10 is a valuable tool for assessing executive function (EF) among stroke patients because it can provide in-depth information on the process and quality of performance. This study also demonstrates the need to use performance-based tests even with patients who perform normally on cognitive screening tests to detect subtle EF difficulties that may affect daily functioning. Primary Author and Speaker: Chen Gong Contributing Authors: Ninghua Wang

The length of the single-phase line of the Sutong GIL tunnel is about 6km, and the length of a single gas chamber is about 100m. Because the GIL adopts a fully sealed design, it is difficult for the existing methods to accurately locate the fault when discharge and overheat faults occur during operation. In order to meet the long-distance fault location requirement of Sutong GIL, this paper analyzed the breakdown, propagation and attenuation characteristics of ultrasonic signals in GIL through test. The test results show that the frequency of the ultrasonic signal generated by breakdown should be distributed in the frequency of 40$\sim$60kHz, 100$\sim$150kHz, 230$\sim$250kHz and 500$\sim$530kHz. In addition, the attenuation of ultrasonic signal is 70% and 89% after passing through the gas chamber basin and expansion joint. Based on the above research results, this paper designed the configuration and parameters of the sensors, communication scheme and protection scheme of the long-distance GIL ultrasonic fault location system in detail, and verified the fault location function of the system through engineering app-cations.

Quantitative research of urban geography has benefited greatly from the rapid development of big geo-data. Spatial assembly is an essential analytical step to summarize and perceive geographical environment from individual behaviours. Most research focuses on the methodology of how to utilize the big data, while the adopted spatial units for data aggregation remain areal in nature. This article conceptually proposes an idea of sensing cities from a street perspective, emphasizes the significance of street units in quantitative urban studies. Using a three-month taxi trajectory dataset and the major streets in Beijing, we explore the spatio-temporal patterns of urban mobility on streets, cluster streets into nine types based on their dynamic functions and capacities. Additionally, we discuss the differences and connections between the linear street unit and traditional areal units, investigate the possibility of uncovering urban communities using streets, and point out the complexity of streets. We conclude that street unit as a supplement to areal units, is able to effectively minify the modifiable areal unit problem (MAUP), sense urban dynamics, depict urban functions, and understand urban structures.

The range of motion (ROM) measurement is an important issue in a robot-assisted ankle–foot rehabilitation. This study presents a therapist-joined method to improve the ROM measurement accuracy of a robotic ankle–foot rehabilitation system by combining therapist-joined zero-torque control and proxy-based sliding mode control. The zero-torque control is applied when measuring the subject’s range of motion to obtain its extreme joint angle and largest resistance torque. Moreover, a controller switch is applied to ensure that the extreme joint angle is appropriate. Comparative studies between the ROM measurement using a protractor and the proposed method are then performed, comparing the ankle resistance torque variations during stretching under different ROM-measuring results. Ten able-bodied subjects are recruited for this experiment. The results show that the proposed method is feasible in improving the measured ROM accuracy. In addition, a more accurate ROM leads to a larger improvement of the ankle stiffness.

Kidney renal clear cell carcinoma (KIRC) is the most common type of renal cell carcinoma. While a number of treatments have been developed over the past few decades, the prognosis of patients with KIRC remains poor due to tumor metastasis and recurrence. Therefore, the molecular mechanisms of KIRC require to be elucidated in order to identify novel biomarkers. MicroRNAs (miRNAs/miRs) have been studied as important regulators of gene expression in a variety of cancer types. In the present study, a bioinformatics analysis of differentially expressed miRNAs in KIRC vs. normal tissues was performed based on raw miRNA expression data and patient information downloaded from the The Cancer Genome Atlas database. Furthermore, the clinical significance of differentially expressed miRNAs was evaluated, and their target genes and biological effects were further predicted. After applying the cut-off criteria of an absolute fold change of ≥2 and P

Kidney renal clear cell carcinoma (KIRC) is the most common and aggressive type of renal cell carcinoma. Due to high mortality rate, high metastasis rate and chemical resistance, the prognosis of KIRC patients is poor. Therefore, it is necessary to study the mechanisms of KIRC development and to develop more effective prognostic molecular biomarkers to help clinical patients. In our study, we used The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases to investigate that the expression of nuclear factor I B (NFIB) is significantly higher in KIRC than in adjacent tissues. Moreover, NFIB expression levels are associated with multiple clinical pathological parameters of KIRC, and KIRC patients with high NFIB expression have poor prognosis, suggesting that NFIB may play vital roles in the malignant development of KIRC. Further studies demonstrated that NFIB could promote the progression and metastasis of KIRC and participate in the regulation of PTEN induced kinase 1 (PINK1). Furthermore, we used chromatin immunoprecipitation (ChIP) experiments to confirm that NFIB binds to the PINK1 promoter and regulates its expression at the transcriptional level. Further experiments also confirmed the important roles of PINK1 in promoting the development of tumors by NFIB. Hence, our data provide a new NFIB-mediated regulatory mechanism for the tumor progression of KIRC and suggest that NFIB can be applied as a new predictor and therapeutic target for KIRC.

Tube hydroforming (THF) under pulsating hydraulic pressures is a novel technique that applies pulsating hydraulic pressures that are periodically increased to deform tubular materials. The deformation behaviours of tubes in pulsating THF may differ compared to those in conventional non-pulsating THF due to the pulsating hydraulic pressures. The equivalent stress-strain relationship of metal materials is an ideal way to describe the deformation behaviours of the materials in plastic deformation. In this paper, the equivalent stress-strain relationships of SS304 tubes in pulsating hydroforming are determined based on experiments and simulation of free hydraulic bulging (FHB), and compared with those of SS304 tubes in non-pulsating THF and uniaxial tensile tests (UTT). The effect of the pulsation parameters, including amplitude and frequency, on the equivalent stress-strain relationships is investigated to reveal the plastic deformation behaviours of tubes in pulsating hydroforming. The results show that the deformation behaviours of tubes in pulsating hydroforming can be well described by the equivalent stress-stain relationship obtained by the proposed method. The amplitude and frequency of pulsating hydraulic pressure have distinct effects on the equivalent stress-strain relationships-the equivalent stress becomes augmented and the formability is enhanced with the increase of the pulsation amplitude and frequency.

Rationale Stroke is the leading cause of death and disability in rural China. For stroke patients residing in resource-limited rural areas, secondary prevention and rehabilitation are largely unavailable, and where present, are far below evidence-based standards. Aim This study aims to develop and implement a simplified stroke rehabilitation program that utilizes nurses and family caregivers for service delivery, and evaluate its feasibility and effectiveness in rural China. Methods and design This 2-year randomized controlled trial is being conducted in 2–3 county hospitals located in northwest, northeast, and southwest China. Eligible and consenting stroke inpatients (200 in total) have been recruited and randomized into either a control or intervention group. Nurses in the county hospital are trained by rehabilitation specialists and in turn train the family caregivers in the intervention group. They also provide telephone follow-up care three times post discharge. The recruitment, baseline, intervention, follow-up care, and evaluation are guided by the RECOVER mobile phone app specifically designed for this study. Study outcome The primary outcome is patients’ Barthel Index (activities of daily living: mobility, self-care, and toileting) at 6 months. Process and economic evaluation will also be conducted. Discussion The results of our study will generate initial high-quality evidence to improve stroke care in resource-scarce settings. If proven effective, this innovative care delivery model has the potential to improve the health and function of stroke patients, relieve caregiver burden, guide policy-making, and advance translational research in the field of stroke care.

Robotic platform based ankle-foot rehabilitation systems have been proved effective in treating joint spasticity and/or contracture of stroke survivors. However, simple force or velocity limiters are not adequate, since they cannot explicitly guarantee slow and overdamped motions without overshoot. In this paper, we propose a proxy-based sliding mode control (PSMC) based approach, to avoid unsafe behaviors of a robotic ankle-foot rehabilitation system. The proposed method has three advantages: 1) without deteriorating tracking performance during normal operation, it guarantees overdamped, slow and safe recoveries after abnormal events; 2) it provides a simple and accurate way to confine the output torque exerted on the subject's ankle; 3) though effective, the control law avoids the necessity to identify the specific system model or build state observer, which is usually difficult for human-robot interaction system. A 71-year-old stroke patient and ten able-bodied subjects were recruited for the experiments. Preliminary studies comparing PSMC and PID are performed on trajectory tracking, controlled torque output, slow and safe response under disturbance. Additionally, by fulfilling the rehabilitation method and obtaining biomechanical indicators, the proposed controller is proved to be feasible for the system.

In this paper, we present an Inertial Measurement Unit (IMU) based gait phase detection system for stroke survivors. The system consists of two IMUs tied to the thigh and shank respectively, for collecting acceleration and angular velocity during walking. Features are extracted using a 150ms sliding window and processed by a quadratic discriminant analysis classifier. Three stroke survivors were recruited with varying degrees of walking disability to test our system, and the experimental environment was level walking at preferred speeds. Experimental results show that the IMU-based gait phase detection system can accurately identify the swing phase and the stance phase, with a recognition accuracy higher than 97 %. Also, we figure out that the recognition results of utilizing one IMU alone is almost equal to the results of using two IMUs together. This study provides an idea for further research on wearable rehabilitation robots for stroke survivors.

Ankle joint with spasticity and/or contracture can severely disable the mobility and the independence of stroke survivors. In this paper, we developed a proprioceptive neuromuscular facilitation (PNF) integrated robotic ankle-foot system for post stroke rehabilitation. The system consists of a robotic platform and a control system with graphic user interface. We employ five normal subjects to test the reliability and feasibility of the proposed system. To validate the effectiveness of the PNF integrated robotic system, we recruit five stroke patients and carry out a six-week PNF treatment. Treatment outcome was evaluated quantitatively in passive and active joint properties. The passive hysteresis loop shows that the maximum dorsiflexion angle increases from 32.9 Â? Â? 1.5 Â? to 42.0 Â? Â? 3.2 Â? ( p = 0.014 ) while the resistance torque decreases from 45.6Â?NmÂ?5.8Â?NÂ?m to 29.8Â?NÂ?mÂ?4.4Â?NÂ?m ( p = 0.019 ). The active joint properties are improved significantly with the training score increasing from 5.7 Â? 0.9 to 8.1 Â? 0.6 , and getting close to that of normal subjects ( 9.5 Â? 0.3 ). In addition, muscle strength has a rising trend as time goes on. The results demonstrate that the proposed PNF integrated robotic ankle-foot rehabilitation system is effective in improving ankle spasticity and/or contracture and is a promising solution in clinical rehabilitation. We developed a proprioceptive neuromuscular facilitation (PNF) integrated robotic ankle-foot system for post stroke rehabilitation.It is the first time that PNF method has been used in ankle spasticity/contracture rehabilitation.Five able-bodied subjects participated in the experiments and five stroke patients were recruited with a six-week PNF treatment.The proposed system can offer more effective treatment than passive stretching in improvement of both passive and active joint properties.

Although survival analysis is known to outperform logistic regression, theoretically and according to evidence from other disciplines, little is known about how true this is in situations where the goal is detecting spatial predictors of land change. Furthermore, with the increasing availability of longitudinal land-change data, evidence is needed on the relative performance of these two different methods in situations with differing levels of data abundance. To fill this gap, we generated a pseudo land-change data set using an agent-based model of residential development in a virtual landscape. This agent-based model simulated the decisions of homebuyers in choosing residential locations based on the values of several spatial variables. Pseudo land-change maps, generated by the agent-based model with different weights on these spatial variables, were exposed to statistical analysis under the logistic and survival approaches. We evaluated how well the two approaches could reveal the spatial variables that were used in the agent-based model and compared the performance of the two methods when land-change data were collected under different sampling frequencies. Our results suggest that survival analysis outperforms logistic regression in detecting the variables that were included in agent decisions, largely because it takes into account time-dependent variables. Also, this research suggests that various properties of land-change processes like amount of developed area and access of agents to information affect the relative performance of these statistical approaches aimed at uncovering land-change predictor variables.

Gridded time-series data are increasingly available for climatology research. Microwave imagery of snow water equivalent (SWE) has been accumulated at daily basis for over two decades, but complex spatial-temporal patterns in SWE dataset pose great challenges for exploration and interpretation. This paper introduces the use of several perspectives from a tri-space conceptualization of a time series of SWE grids combined with dimensionality reduction via the self-organizing map (SOM) method. While SOM has been predominantly viewed as a clustering mechanism within climatology research, we expand the visual-analytic potential of SOM for climate research with a series of conceptual, computational, and visual transformations. Specifically, we apply a medium-resolution SOM to an SWE dataset covering the Northern Hemisphere over a 20-year period, with high temporal resolution. Through clustering and visualization a number of distinct SWE patterns are identified, including mountainous, coastal, and continental regions. A subset of cells from six areas are selected for transition analysis, including mountainous (Sierra Nevada, Western Himalaya, Eastern Himalaya) and continental (central Siberia, western Russia and Midwest United States) regions. By combining with trajectory analysis, this SOM documents notable transitions in seasonal SWE accumulation and melt patterns in mountain ranges, suggesting that SWE in some geographic locations alternates between different discrete annual patterns. In the Sierra Nevada, transitions to classes with high SWE are shown to be related to the Southern Oscillation Index, demonstrating that the annual patterns and transitions in SWE regime identified by the SOM correspond to synoptic climate conditions.

Stroke patients with hemiparesis often exhibit an asymmetrical weight distribution, with the paretic leg providing less support and less weight-shift activity than the sound leg does. For upper-limb hemiparesis constraint-induced movement therapy (CIMT), where the sound limb is constrained and the patient is forced to use the paretic limb, has proven to be one of the most effective rehabilitation methods. However, this method has not been successfully modified for balance rehabilitation, since hard constraints on the lower limb are difficult to impose and can increase the risk of patient injuries. Here we introduce a novel approach that encourages stroke survivors to use the paretic leg for weight-shifting tasks during balance control training in a virtual reality setting. We recorded motion signals from each leg in real time and streamed modified versions of these signals to the Nintendo Wii Fit gaming system. By independently manipulating the influence of each leg during game play, we successfully forced the stroke survivors to increase the use of the paretic leg. Our preliminary clinical trial, including three patients with hemiparesis in the chronic phase, found that one-week of training improved patients’ ability to maneuver their center of pressure (COP) during a tracking task. More encouragingly, patient’s weight distributions became more symmetrical. These initial results suggest that manipulating control gains during VR rehabilitation may allow the principles of CIMT to be applied during balance training in stroke survivors.

In this paper, we aim to investigate the effect of proprioceptive neuromuscular facilitation (PNF)-based rehabilitation for ankle plantar flexors spasticity by using a Robotic Ankle–foot Rehabilitation System (RARS). A modified robot-assisted system was proposed, and seven poststroke patients with hemiplegic spastic ankles participated in a 3-month robotic PNF training. Their impaired sides were used as the experimental group, while their unimpaired sides as the control group. A robotic intervention for the experimental group started from a 2-min passive stretching to warming-up or relaxing the soleus and gastrocnemius muscles and also ended with the same one. Then a PNF training session including 30 trials was activated between them. The rehabilitation trainings were carried out three times a week as an addition to their regular rehabilitation exercise. Passive range of motion, resistance torque, and stiffness were measured in both ankles before and after the interventions. The changes in Achilles tendon length, walking speed, and lower limb function were also evaluated by the same physician or physiotherapist for each participant. Biomechanical measurements before interventions showed significant difference between the experimental group and the control group due to ankle spasticity. For the control group, there was no significant difference in the 3 months with no robotic intervention. But for the experimental group, passive dorsiflexion range of motion increased (p 0.05). The robotic rehabilitation also improved the muscle strength (p 0.05), and fast walking speed (p

Polyethylene is widely used in electrical wires and power cables. The pre-stressing effect, which restricts the applications of polyethylene, has not yet been investigated in depth. We studied the breakdown of low-density polyethylene (LDPE) films pre-stressed by direct current (DC) electric field. The results showed some conformity, as reported in many other papers, that the DC breakdown strength E B+ with the same polarity to that of the pre-stressing field was higher than the DC breakdown strength E B of thin LDPE films without pre-stressing, while the DC breakdown strength E B − with the opposite polarity was lower than E B . Such phenomena could be explained by the hetero effects of accumulating space charges, which enhanced the electrical field when the polarity was reversed. However, as a further increase in pre-stressing electrical field, both E B+ and E B − were found higher than E B . We investigated the space charge behavior in LDPE films and found that when applied with a higher electrical field, space charge packet initialized and traveled through the specimen. The results suggest that the space charge packet behavior may contribute to the pre-stressing effects on electrical breakdown in LDPE films.

The wide use of high voltage direct current (HVDC) equipments, such as convert transformer, DC bushing, DC cables, makes the research of oil-paper material insulation extraordinarily important. The space charge effect is the key insulation problem of HVDC equipments. This paper studied the space charge characteristics of oil-paper insulation materials by Pulsed Electro-Acoustic (PEA) method. In this paper, we studied and discussed the relationship between space charge and breakdown in oil-paper. The results show that the space charge comes from ionization at lower field intensity. When the stress is getting higher, injection of homo carriers occurs first at cathode and later at anode. The space charge inside oil-paper sample results in an electrical field distortion up to 40%. The conductivity of oil-paper insulation material is much larger than that of polyethylene, so the space charge dissipates fast when depolarized. The fast dissipation of space charge will play a key role of oil-paper insulating performance in condition of polarity reversal under HVDC. When the applied negative electrical field rose to between 50 kV/mm and 57 kV/mm, the oil-paper material got breakdown in a short time. During this process, an obvious movement of space charge was observed.

In this paper, a needle–plane electrode system and polypropylene (PP) films were used to study the DC corona charging of polymers. It was found that the charges injected into the PP films sometimes show different polarity to the applied DC voltage, called polarity reversal charging, which may results in invalidation charging. The pulsed electro-acoustic (PEA) space charge measurement showed that charges of different polarities have been injected into the PP films’ bulk, simultaneously. From these results, a mechanism of two charging processes of high-field injection and return-stroke injection has been introduced here. We presumed that the return-stroke injection can be boosted with the increase of corona voltages and thus reduces the net charge as well as even change the polarity of charges injected.

In this paper, three kinds of annealing methods with different cooling rates are used to prepare low-density polyethylene (LDPE) samples with different microstructure in crystallinity. The effects of crystallinity on space charge properties are investigated. It was found that homo-charges are easier to accumulate in high rate cooling sample and hetero-charges are easier to accumulate near cathode in low rate cooling sample. It was also found that charge movement and neutralization occurs with the increases of the applied field and the voltage applying duration. Based on these results, the influence of crystallinity on space charge accumulation is emphasized.

In this paper, low density polyethylene (LDPE) film samples were prepared by three kinds of annealing methods which were different in cooling rates. Lower cooling rate results in larger spherulite and higher crystallinity. A pulsed electro-acoustic (PEA) space charge measurement system was improved to solve the surface discharge problems for high voltage and small samples. Negative DC fields from 50 to 220 kV/mm were applied on the samples. The influences of annealing methods on space charge and space charge packet characteristics were measured by the improved PEA system. Mobility and trap depth of released charges were calculated by space charge decay which was measured by PEA method. Average velocity and mobility of space charge packets were calculated by space charge packet dynamics. It's found that the lower rate cooling samples have higher crystallinity, more homo-charge accumulation, lower mobility and deeper trap depth. We presumed there are inherent relationships in existence.

Annealing effects on the tree initiation voltage of high density polyethylene (HOPE) are studied. Three annealing methods with different cooling velocity were used in preparation of the samples. The samples cooled in high velocity were reheated and recooled. The crystallinity of these samples was measured. Recrystallization process was found. Put samples in oil with high temperature. For the samples cooled in low velocity and normal velocity, tree initiation voltage decreases with temperature increases. For samples cooled in high velocity, when the heating temperature is higher than 90 /spl deg/C, tree initiation voltage increases abnormally and then decreases with heating duration in high temperature. In addition, tree initiation voltage of samples increase and then decrease with heating temperature increases. We presumed that the morphological microstructure and the recrystallization processes in samples are responsible for above phenomena.

In this paper, high-density polyethylene (HDPE) films were prepared by three kinds of annealing methods which were different in cooling speed. The crystallinity of those HDPE samples were measured and compared. A high DC voltage was applied to the samples and the space charge formed was measured. Homo-charges were found in samples that were applied with a negative high voltage. The space charge properties were discussed, based on crystallinity. From these results, it is found that the space charge formed in samples cooled at high speed is more than that of the samples cooled at normal and low speed.

In this paper, influences of some factors on the electrical conduction in high-density polyethylene (HDPE) films are studied. HDPE samples with different thickness have been prepared. Their differences in DC electrical conduction are reported and discussed. It's found that the samples with different thickness have different DC conduction properties, the current density increases and then decreases with the increase of the thickness of samples. On the other hand, in the current density measurements, electrodes made of different metal materials including copper, aluminum, and steel have been used. The influences of different metal electrodes on DC conduction in HDPE films are discussed.

In this paper, a needle-plane electrode system and non woven polypropylene filters were used to study the space charge formation on the surface of dielectrics by nanosecond pulse discharge. Ordinarily, the charging of polymers shows the same polarity as the voltage applied. A novel discovery of polarity reversal discharge was found that the accumulated space charges on the surface of polymers show a different polarity against the applied pulse. It was found that a higher positive pulse peak leads to easier polarity reversal charge accumulation in polymers. It was also found that a negative pulse causes a positive charge accumulation when the peak is sufficient high and the pulse width is sufficient small. In addition, a negative pulse will produce the same polarity of charges on the surface of polymers when the width of pulse is larger than 200 ns. A novel mechanism of two charging processes of high fluid injection and return stroke injection has been put forward here to fit the polarity reversal charging phenomena. We concluded that the polarity reversal charging of polymers can be inherently related to the discharge in gases and the needle-plane electrode system.

To delineate the influence of transcutaneous electrical nerve stimulation (TENS) on heat pain threshold and vibration threshold in human.Twenty healthy, young subjects, aged from 20 to 39, participated in the study. They were randomly allocated into either TENS or placebo group. Thirty minutes of conventional TENS (200 micro s pulses at 100 Hz and 2 - 3 times sensory threshold) or placebo stimulation was applied to the acupuncture points (LI4) on each subject's left hand. Heat pain and vibration thresholds were measured using Medoc TSA-2001 and VSA-3000 respectively on the thenar eminence of each subject's left hand. These assessments were done at 30, 20 and 10 minutes before and 0, 10, 20, 30, 40 and 50 minutes after 30 minutes of TENS or placebo treatment.This study showed a significant increase in heat pain threshold by 0.81 degrees C and 1.54 degrees C respectively at 0 (P = 0.002) and 20 minutes (P = 0.004) after 30 minutes of TENS application to the LI4 acupoint of young healthy subjects, compared with placebo stimulation. Interestingly, no significant difference in vibration threshold was found between the TENS and placebo groups.The effect of TENS on the acupoint is to reduce pain but not tactile (specifically vibration) sensibility.