434 research outputs found
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A Simple Graphene NH₃ Gas Sensor via Laser Direct Writing.
Ammonia gas sensors are very essential in many industries and everyday life. However, their complicated fabrication process, severe environmental fabrication requirements and desorption of residual ammonia molecules result in high cost and hinder their market acceptance. Here, laser direct writing is used to fabricate three parallel porous 3D graphene lines on a polyimide (PI) tape to simply construct an ammonia gas sensor. The middle one works as an ammonia sensing element and the other two on both sides work as heaters to improve the desorption performance of the sensing element to ammonia gas molecules. The graphene lines were characterized by scanning electron microscopy and Raman spectroscopy. The response and recovery time of the sensor without heating are 214 s and 222 s with a sensitivity of 0.087% ppm-1 for sensing 75 ppm ammonia gas, respectively. The experimental results prove that under the optimized heating temperature of about 70 °C the heaters successfully help implement complete desorption of residual NH₃ showing a good sensitivity and cyclic stability
Nuclei micro-array FISH, a desirable alternative for MCL diagnosis
Mantle cell lymphoma (MCL) is a rare, specific lymphoma subtype. Though the morphologic and immunophenotypic features of MCL have been well described in recent literatures, it is still a diagnostic dilemma because of its frequent confusion with other small B cell lymphomas (SBCLs). In the present study, we primarily focus on establishing a sensitive and specific method for the diagnosis of MCL, which is efficient to distinguish this disease from other SBCLs. We carried out our investigation for MCL and other SBCLs (including SLL, FL, MZL, and MALT) on their feature of morphology, immunophenotype, and t(11;14)(q13;q32) translocation analysis based on polymerase chain reaction (PCR) and interphase nuclei micro-array fluorescence in situ hybridization (FISH). The morphologic and immunologic analysis showed the positive rate of cyclin D1 was 76.47% in MCL, which was significantly higher than that in other SBCLs. The positive rate of t(11;14) translocation was 25.81% and 35.48%, respectively, tested by general and semi-nested PCR, while 93.10% positive rate was shown with low background and strong signals pattern when tested by Nuclei micro-array FISH. Our research shows that t(11;14) translocation is a special and useful diagnostic marker for MCL, and detection of the marker by nuclei micro-array FISH is convenient and economic, especially more sensitive and specific than other methods for the diagnosis of MCL
Protective effect of extract of Cordyceps sinensis in middle cerebral artery occlusion-induced focal cerebral ischemia in rats
<p>Abstract</p> <p>Background</p> <p>Ischemic hypoxic brain injury often causes irreversible brain damage. The lack of effective and widely applicable pharmacological treatments for ischemic stroke patients may explain a growing interest in traditional medicines. From the point of view of "self-medication" or "preventive medicine," <it>Cordyceps sinensis </it>was used in the prevention of cerebral ischemia in this paper.</p> <p>Methods</p> <p>The right middle cerebral artery occlusion model was used in the study. The effects of <it>Cordyceps sinensis </it>(Caterpillar fungus) extract on mortality rate, neurobehavior, grip strength, lactate dehydrogenase, glutathione content, Lipid Peroxidation, glutathione peroxidase activity, glutathione reductase activity, catalase activity, Na<sup>+</sup>K<sup>+</sup>ATPase activity and glutathione S transferase activity in a rat model were studied respectively.</p> <p>Results</p> <p><it>Cordyceps sinensis </it>extract significantly improved the outcome in rats after cerebral ischemia and reperfusion in terms of neurobehavioral function. At the same time, supplementation of <it>Cordyceps sinensis </it>extract significantly boosted the defense mechanism against cerebral ischemia by increasing antioxidants activity related to lesion pathogenesis. Restoration of the antioxidant homeostasis in the brain after reperfusion may have helped the brain recover from ischemic injury.</p> <p>Conclusions</p> <p>These experimental results suggest that complement <it>Cordyceps sinensis </it>extract is protective after cerebral ischemia in specific way. The administration of <it>Cordyceps sinensis </it>extract significantly reduced focal cerebral ischemic/reperfusion injury. The defense mechanism against cerebral ischemia was by increasing antioxidants activity related to lesion pathogenesis.</p
Specific frequency bands of amplitude low-frequency fluctuations in memory-related cognitive impairment: predicting Alzheimer’s disease
Resting-state functional magnetic resonance imaging was utilized to measure the amplitude low frequency fluctuations (ALFF) in human subjects with Alzheimer’s disease (AD) and normal control (NC). Two specific frequency bands (Slow5: 0.01-0.027Hz and Slow4: 0.027-0.073Hz) were analysed in the main cognitive control related four subregions of the right ventral lateral prefrontal cortex (VLPFC), i.e. IFJ, posterior-VLPFC, mid-VLPFC, and anterior-VLPFC. Differences in ALFF values between the AD and the NC group were found throughout the subregions of the right VLPFC. Compared to normal control group, decreased ALFF values were observed in AD patients in the IFJ (in two given frequency bands), and the mid-VLPFC (in Slow5). In contrast, increased ALFF valued were observed in AD patients in the posterior- and anterior-VLPFC (in both Slow5 and Slow4), and also in the mid-VLPFC in Slow4. Moreover, significant ALFF differences between the IFJ and three other subregions of the right VLPFC were found. Furthermore, ALFF values in the right VLPFC showed significant correlations with the time course of disease. Taken together, our findings suggest that AD patients have largely abnormalities in intrinsic neural oscillations which are in line with the AD pathophysiology, and further reveal that the abnormalities are dependent on specific frequency bands. Thus, frequency-domain analyses of the ALFF may provide a useful tool to investigate the AD pathophysiology
Identify the radiotherapy-induced abnormal changes in the patients with nasopharyngeal carcinoma
Radiotherapy (RT) is the standard treatment for nasopharyngeal carcinoma, which often causes inevitable brain injury in the process of treatment. The majority of patients has no abnormal signal or density change of the conventional magnetic resonance imaging (MRI) and computed tomography (CT) examination in the long-term follow-up after radiation therapy. However, when there is a visible CT and conventional MR imaging changes, the damage often has been severe and lack of effective treatments, seriously influencing the prognosis of patients. Therefore, the present study aimed to investigate the abnormal changes in nasopharyngeal carcinoma (NPC) patients after RT. In the present study, we exploited the machine learning framework which contained two parts: feature extraction and classification to automatically detect the brain injury. Our results showed that the method could effectively identify the abnormal regions reduced by radiotherapy. The highest classification accuracy was 82.5 % in the abnormal brain regions. The parahippocampal gyrus was the highest accuracy region, which suggested that the parahippocampal gyrus could be most sensitive to radiotherapy and involved in the pathogenesis of radiotherapy-induced brain injury in NPC patients
Explore postgraduate biomedical engineering course integration between medical signal processing and drug development: example for drug development in brain disease
Medical signal processing is a compulsory course in our university’s undergraduate biomedical engineering programme. Recently, application of medical signal processing in supporting new drug development has emerged as a promising strategy in neurosciences. Here, we discuss the curriculum reformation in biomedical signal processing course in the context of drug development and application in central nervous system, with a particular emphasis in knowledge integration
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