5,709 research outputs found
Stress Analysis Of Stretchable Thermal Sensor
This paper present a summary of the performance of modelling for stretchable circuit. For this new technology, the stretchable board can achieve mechanically bendable and stretchable by using the elastomer based substrate and interconnect. Hence, the study on mechanical properties of substrate effect on design of interconnect is important on the fatigue lifetime and reliability of circuit. Nowadays, the reliability of stretchable circuit is still an existing issue when it continuously supplied by cyclic stresses which will cause the elastic strain deformation during stretch and compress. The purpose of this paper is to present the stress and strain deformation on the interconnect design and reliability of stretchable circuit. By using the Finite Element Method (FEM), it enables to define a more reliable design and suitable material of the stretchable circuit. The stretchability performance can be evaluated on the strain and stress applied to the interconnect and substrate. Suitable material properties of substrate able to offer the less damage during elongation. PDMS and TPU are chosen as material of substrates because of its high elongation before break and it allows high stretchability. This study demonstrates the effect of stress and strain deformation on new design of stretchable board by using proposed material for the substrates at different elongation
A Structured Training Course for Non-structured Design Course
In an engineering design course, teaching assistant plays a critical role to in supporting the teaching and the learning process for the participants – students and instructors. The instructors would invite or hire a postgraduate student to be the teaching assistant. In most cases, the postgraduate student does not has any teaching experience. This work proposed and implemented a quick start training course for the teaching assistant specifically for an engineering design course, by adopting concept-design-implementation-operation
Did the S.A.R.S. epidemic weaken the integration of Asian stock markets? Evidence from smooth time-varying cointegration analysis
The purpose of this study is to examine the effect of the Severe
Acute Respiratory Syndrome (S.A.R.S.) epidemic on the long-run
relationship between China and four Asian stock markets. To this
end, we first employ the advanced smooth time-varying cointegration
model to investigate the existence of a time-varying cointegration
relation among these markets and then employ the difference-indifferences
approach to analyse whether or not the S.A.R.S. epidemic
impacted the long-run relation between China and these four markets
during the period 1998–2008, covering 5 years before and after the
S.A.R.S. outbreak. Our results support the existence of a time-varying
cointegration relation in the aggregate stock price indices, and that
the S.A.R.S. epidemic did weaken the long-run relationship between
China and the four markets. Therefore, stockholders and policy makers
should be concerned about the influence of catastrophic epidemic
diseases on the financial integration of stock market in Asia
Multidetector CT Findings of a Congenital Coronary Sinus Anomaly: a Report of Two Cases
Congenital coronary sinus anomalies are extremely rare, and they have received relatively little attention. This is probably due to the lack of both clinical symptoms and significant cardiac functional disturbance. We present two cases of a coronary sinus anomaly and briefly review the literature. Recognizing and being familiar with the variations of a congenital coronary sinus anomaly in congenital heart disease may avoid a misinterpretation of cardiac catheterization findings and the troublesome disruption of coronary sinus blood return during the surgical management of cardiac lesions
Mozart K.448 listening decreased seizure recurrence and epileptiform discharges in children with first unprovoked seizures: a randomized controlled study
BACKGROUND: Increasing numbers of reports show the beneficial effects of listening to Mozart music in decreasing epileptiform discharges as well as seizure frequency in epileptic children. There has been no effective method to reduce seizure recurrence after the first unprovoked seizure until now. In this study, we investigated the effect of listening to Mozart K.448 in reducing the seizure recurrence rate in children with first unprovoked seizures. METHODS: Forty-eight children who experienced their first unprovoked seizure with epileptiform discharges were included in the study. They were randomly placed into treatment (n = 24) and control (n = 24) groups. Children in the treatment group listened to Mozart K.448 daily before bedtime for at least six months. Two patients in the treatment group were excluded from analysis due to discontinuation intervention. Finally, forty-six patients were analyzed. Most of these patients (89.1%) were idiopathic in etiology. Seizure recurrence rates and reduction of epileptiform discharges were compared. RESULTS: The average follow-up durations in the treatment and control groups were 18.6 ± 6.6 and 20.1 ± 5.1 months, respectively. The seizure recurrence rate was estimated to be significantly lower in the treatment group than the control group over 24 months (37.2% vs. 76.8%, p = 0.0109). Significant decreases in epileptiform discharges were also observed after 1, 2, and 6 months of listening to Mozart K.448 when compared with EEGs before listening to music. There were no significant differences in gender, mentality, seizure type, and etiology between the recurrence and non-recurrence groups. CONCLUSIONS: Although the case number was limited and control music was not performed in this study, the study revealed that listening to Mozart K.448 reduced the seizure recurrence rate and epileptiform discharges in children with first unprovoked seizures, especially of idiopathic etiology. We believe that Mozart K.448 could be a promising alternative treatment in patients with first unprovoked seizures and abnormal EEGs. Further large-scaled study should be conducted to confirm the effect. TRIAL REGISTRATION: NCT01892605, date: June-19-201
Evaluation of Antioxidant and Free Radical Scavenging Capacities of Polyphenolics from Pods of Caesalpinia pulcherrima
Thirteen polyphenolics were isolated from fresh pods of Caesalpinia pulcherrima using various methods of column chromatography. The structures of these polyphenolics were elucidated as gallic acid (1), methyl gallate (2), 6-O-galloyl-d-glucoside (3), methyl 6-O-galloyl-β-d-glucoside (4), methyl 3,6-di-O-galloyl-α-d-glucopyranoside (5), gentisic acid 5-O-α-d-(6′-O-galloyl)glucopyranoside (6), guaiacylglycerol 4-O-β-d-(6′-O-galloyl)glucopyranoside (7), 3-methoxy-4-hydroxyphenol 1-O-β-d-(6′-O-galloyl) glucopyranoside (8), (+)-gallocatechin (9), (+)-catechin (10), (+)-gallocatechin 3-O-gallate (11), myricetin 3-rhamnoside (12), and ampelopsin (13). All isolated compounds were tested for their antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and peroxynitrite radicals scavenging assays. Among those compounds, 11, 12, and 2 exhibited the best DPPH-, hydroxyl-, and peroxynitrite radical-scavenging activities, respectively. Compound 7 is a new compound, and possesses better scavenging activities towards DPPH but has equivalent hydroxyl radical scavenging activity when compared to BHT. The paper is the first report on free radical scavenging properties of components of the fresh pods of Caesalpinia pulcherrima. The results obtained from the current study indicate that the free radical scavenging property of fresh pods of Caesalpinia pulcherrima may be one of the mechanisms by which this herbal medicine is effective in several free radical mediated diseases
Aspirin prevents resistin-induced endothelial dysfunction by modulating AMPK, ROS, and Akt/eNOS signaling
BackgroundResistin, an adipocytokine, plays a potential role in cardiovascular disease and may contribute to increased atherosclerotic risk by modulating the activity of endothelial cells. A growing body of evidence suggests that aspirin is a potent antioxidant. We investigated whether aspirin mitigates resistin-induced endothelial dysfunction via modulation of reactive oxygen species (ROS) generation and explored the role that AMP-activated protein kinase (AMPK), a negative regulator of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, plays in the suppressive effects of aspirin on resistin-induced endothelial dysfunction.MethodsHuman umbilical vein endothelial cells (HUVECs) were pretreated with various doses of aspirin (10-500 μg/mL) for 2 hours and then incubated with resistin (100 ng/mL) for an additional 48 hours. Fluorescence produced by the oxidation of dihydroethidium (DHE) was used to quantify the production of superoxide in situ; superoxide dismutase (SOD) and catalase activities were determined by an enzymatic assay; and protein levels of AMPK-mediated downstream signaling were investigated by Western blot.ResultsTreatment of HUVECs with resistin for 48 hours resulted in a 2.9-fold increase in superoxide production; however, pretreatment with aspirin resulted in a dose-dependent decrease in production of superoxide (10-500 μg/mL; n = 3 experiments; all P < .05). Resistin also suppressed the activity of superoxide dismutase and catalase by nearly 50%; that result, however, was not observed in HUVECs that had been pretreated with aspirin at a concentration of 500 μg/mL. The membrane translocation assay showed that the levels of NADPH oxidase subunits p47phoxand Rac-1 in membrane fractions of HUVECs were threefold to fourfold higher in cells that had been treated with resistin for 1 hour than in untreated cells; however, pretreatment with aspirin markedly inhibited resistin-induced membrane assembly of NADPH oxidase via modulating AMPK-suppressed PKC-α activation. Application of AMPKα1-specific siRNA resulted in increased activation of PKC-α and p47phox. In addition, resistin significantly decreased AMPK-mediated downstream Akt/endothelial nitric oxide synthase (eNOS)/nitric oxide (NO) signaling and induced the phosphorylation of p38 mitogen-activated protein kinases, which in turn activated NF-κB-mediated inflammatory responses such as the release of interleukin (IL)-6 and IL-8, the overexpression of adhesion molecules, and stimulation of monocytic THP-1 cell attachment to HUVECs (2.5-fold vs control; n = 3 experiments). Furthermore, resistin downregulated eNOS and upregulated inducible NO synthase (iNOS) expression, thereby augmenting the formation of NO and protein nitrosylation. Pretreatment with aspirin, however, exerted significant cytoprotective effects in a dose-dependent manner (P < .05).ConclusionsOur findings suggest a direct connection between adipocytokines and endothelial dysfunction and provide further insight into the protective effects of aspirin in obese individuals with endothelial dysfunction.Clinical RelevanceResistin has been reported to involve in the inflammatory process, which is a common feature in metabolic syndrome, insulin resistance status, and vascular diseases. This study underscores the potential clinical benefits and application of aspirin in prevention of obese-associated vascular dysfunction
Pullout strength of pedicle screws with cement augmentation in severe osteoporosis: A comparative study between cannulated screws with cement injection and solid screws with cement pre-filling
<p>Abstract</p> <p>Background</p> <p>Pedicle screws with PMMA cement augmentation have been shown to significantly improve the fixation strength in a severely osteoporotic spine. However, the efficacy of screw fixation for different cement augmentation techniques, namely solid screws with retrograde cement pre-filling versus cannulated screws with cement injection through perforation, remains unknown. This study aimed to determine the difference in pullout strength between conical and cylindrical screws based on the aforementioned cement augmentation techniques. The potential loss of fixation upon partial screw removal after screw insertion was also examined.</p> <p>Method</p> <p>The Taguchi method with an L<sub>8 </sub>array was employed to determine the significance of design factors. Conical and cylindrical pedicle screws with solid or cannulated designs were installed using two different screw augmentation techniques: solid screws with retrograde cement pre-filling and cannulated screws with cement injection through perforation. Uniform synthetic bones (test block) simulating severe osteoporosis were used to provide a platform for each screw design and cement augmentation technique. Pedicle screws at full insertion and after a 360-degree back-out from full insertion were then tested for axial pullout failure using a mechanical testing machine.</p> <p>Results</p> <p>The results revealed the following 1) Regardless of the screw outer geometry (conical or cylindrical), solid screws with retrograde cement pre-filling exhibited significantly higher pullout strength than did cannulated screws with cement injection through perforation (<it>p </it>= 0.0129 for conical screws; <it>p </it>= 0.005 for cylindrical screws). 2) For a given cement augmentation technique (screws without cement augmentation, cannulated screws with cement injection or solid screws with cement pre-filling), no significant difference in pullout strength was found between conical and cylindrical screws (<it>p ></it>0.05). 3) Cement infiltration into the open cell of the test block led to the formation of a cement/bone composite structure. Observations of the failed specimens indicated that failure occurred at the composite/bone interface, whereas the composite remained well bonded to the screws. This result implies that the screw/composite interfacial strength was much higher than the composite/bone interfacial strength. 4) The back-out of the screw by 360 degrees from full insertion did not decrease the pullout strength in any of the studied cases. 5) Generally, larger standard deviations were found for the screw back-out cases, implying that the results of full insertion cases are more repeatable than those of the back-out cases.</p> <p>Conclusions</p> <p>Solid screws with retrograde cement pre-filling offer improved initial fixation strength when compared to that of cannulated screws with cement injection through perforation for both the conically and cylindrically shaped screw. Our results also suggest that the fixation screws can be backed out by 360 degrees for intra-operative adjustment without the loss of fixation strength.</p
Developmental Profiles of Preschool Children With Spastic Diplegic and Quadriplegic Cerebral Palsy
Cerebral palsy (CP) is a disorder of movement and posture control with multiple impairments. The clinical manifestations of CP vary among children. The aim of this study was to compare the developmental profiles of preschool children with either of two types of CP: spastic diplegic (SD) CP and spastic quadriplegic (SQ) CP. Relationships between the children's various developmental functions were also investigated. We recruited 137 children with spastic CP, aged 1-5 years (mean age = 3.7 ± 2.1 years), and we classified them into two groups: SD (n = 59) and SQ (n = 78). The comparison group comprised 18 children with typical development. Developmental functions were assessed in all the children, using the Chinese Child Development Inventory with the updated norms. This scale addressed eight functional domains: gross motor ability, fine motor ability, expressive language ability, concept comprehension ability, situation comprehension ability, self-help ability, personal-social skills, and general development. A development quotient (DQ) was determined for each domain as a percentage of the developmental age divided by the chronological age. The developmental profiles of the CP subtypes were found to differ. Children with SQ were found to have lower DQs than those with SD (p < 0.01). There was also a difference in the distribution of DQs between the SD and SQ groups, although the lowest DQ in both groups was for the gross motor domain. An uneven delay in the development of gross motor function was found in both groups of children with CP. Motor functions, including gross motor and fine motor functions, were significantly related to self-help ability. Complex and significant correlations among developmental functions were also identified in children with CP. The findings in the present study may allow clinicians to anticipate the developmental profile of children with CP on the basis of whether they have the SD or SQ subtype. This, in turn, is likely to facilitate individual assessment, goal setting, and the planning of interventions in children with CP
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