140 research outputs found
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Measuring Electric Charge and Molecular Coverage on Electrode Surface from Transient Induced Molecular Electronic Signal (TIMES).
Charge density and molecular coverage on the surface of electrode play major roles in the science and technology of surface chemistry and biochemical sensing. However, there has been no easy and direct method to characterize these quantities. By extending the method of Transient Induced Molecular Electronic Signal (TIMES) which we have used to measure molecular interactions, we are able to quantify the amount of charge in the double layers at the solution/electrode interface for different buffer strengths, buffer types, and pH values. Most uniquely, such capabilities can be applied to study surface coverage of immobilized molecules. As an example, we have measured the surface coverage for thiol-modified single-strand deoxyribonucleic acid (ssDNA) as anchored probe and 6-Mercapto-1-hexanol (MCH) as blocking agent on the platinum surface. Through these experiments, we demonstrate that TIMES offers a simple and accurate method to quantify surface charge and coverage of molecules on a metal surface, as an enabling tool for studies of surface properties and surface functionalization for biochemical sensing and reactions
COMPARISON OF PLAYER’S CENTER OF MASS MOVEMENT BETWEEN HIGH AND LOW IMPACT POSITIONS IN TENNIS FOREHAND STROKE
During the tennis forehand stroke, the displacement of body center of mass (COM) changes with the body movement. The COM movement influences the recovery from one stroke to the next. Therefore, the purpose of this study is to investigate the differences of COM movement and joint kinematics between high and low-impact positions on different skilled players. This study adopted a 3-D motion analysis system for recording and tracing the advanced (n = 5; level 3-4) and intermediate (n = 7; level 5-6) athletes’ motion of whole body during high and low-impact positions in tennis forehand stroke. The results showed that significant difference was not found between both impact positions and level groups in ball velocity. Advanced group showed greater anterior/posterior displacement than the intermediate group in low-impact position that increased the kinetic energy
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In Vivo Photovoltaic Performance of a Silicon Nanowire Photodiode-Based Retinal Prosthesis.
Purpose:For more than 20 years, there has been an international, multidisciplinary effort to develop retinal prostheses to restore functional vision to patients blinded by retinal degeneration. We developed a novel subretinal prosthesis with 1512 optically addressed silicon nanowire photodiodes, which transduce incident light into an electrical stimulation of the remaining retinal circuitry. This study was conducted to evaluate the efficacy of optically driving the subretinal prosthesis to produce visual cortex activation via electrical stimulation of the retina. Methods:We measured electrically evoked potential responses (EEPs) in rabbit visual cortex in response to illumination of the subretinal nanowire prosthesis with pulsed 852-nm infrared (IR) light. We compared the EEP responses to visually evoked potential responses (VEPs) to pulsed 532-nm visible light (positive control) and pulsed 852-nm IR light (negative control). Results:Activating the devices with IR light produced EEP responses with a significantly higher trough-to-peak amplitude (54.17 ± 33.4 μV) than IR light alone (24.07 ± 22.1 μV) or background cortical activity (23.22 ± 17.2 μV). EEP latencies were significantly faster than focal VEP latencies. Focal VEPs produced significantly higher amplitudes (94.88 ± 43.3 μV) than EEPs. We also demonstrated how an electrode placed on the cornea can be used as a noninvasive method to monitor the function of the implant. Conclusions:These results show that subretinal electrical stimulation with nanowire electrodes can elicit EEPs in the visual cortex, providing evidence for the viability of a subretinal nanowire prosthetic approach for vision restoration
EVALUATION OF ELBOW AND FOREARM MOTION BETWEEN SIDEARM AND OVERHAND PITCHING
This study is to analyze the differences in kinematics, electromyography (EMG) and ultrasonography between two types of pitchers. We intend to observe and simulate the muscles around glenohumeral and elbow joints in different pitching motions and hope to discover the connections and differences in between. 12 pitchers from the top level were recruited. Larger elbow flexion was found in sidearm pitchers during the acceleration phase. Decrease of the distance of nerve to medial epicondyle was also found as the elbow moved to a more flexed position. More anterior translation of the ulnar nerve might occur during acceleration phase. Slightly lower flexor carpi radialis (FCR) activity was displayed in sidearm pitchers, showing that FCR might play a less crucial role in protecting medial elbow by providing less varus torque
Network Biology of Tumor Stem-like Cells Identified a Regulatory Role of CBX5 in Lung Cancer
Mounting evidence links cancers possessing stem-like properties with worse prognosis. Network biology with signal processing mechanics was explored here using expression profiles of a panel of tumor stem-like cells (TSLCs). The profiles were compared to their parental tumor cells (PTCs) and the human embryonic stem cells (hESCs), for the identification of gene chromobox homolog 5, CBX5, as a potential target for lung cancer. CBX5 was found to regulate the stem-like properties of lung TSLCs and was predictive of lung cancer prognosis. The investigation was facilitated by finding target genes based on modeling epistatic signaling mechanics via a predictive and scalable network-based survival model. Topologically-weighted measurements of CBX5 were synchronized with those of BIRC5, DNMT1, E2F1, ESR1, MLH1, MSH2, RB1, SMAD1 and TAF5. We validated our findings in another Taiwanese lung cancer cohort, as well as in knockdown experiments using sh-CBX5 RNAi both in vitro and in vivo.National Science Council (China) (NSC grant 100-2325-B-010-010-MY3/98-2314-B-010-024-MY2/97-3111-B075-001-MY3/ 96-2314-075-056-MY3)National Yang-Ming University (Ministry of Education, Aim for the Top University Plan: 96ADD122, 96ADD125, 96ADT191, 97ACD113, 97ACT302, 98ACT302, 98ACD107, 98ACT192 and Brain Research Center-3T-MRI project)))Taipei Veterans General Hospital (98-C1-099/E1-003/ER3-001)Taipei Veterans General Hospital (Joint Projects of VGHUST (98-G6-6/ 98-P1-01/99-P6-39)Chi Mei Medical Center (CMYM9801)Yen-Tjing-Ling Medical Foundation (96/97/98)Taipei City Hospital (96-002-62-092)Technology Development Program for Academia (TDPA; 98-EC-17-A-19-S2-0107)Taiwan. Department of Industrial Technology, Ministry of Economic AffairsNational Science Council (China) (NSC 101-2325-B-010 -009)Taiwan. Department of Health. Cancer Research Center of Excellence (DOH101-TD-C-111-007
Immuno-modulatory activity of Ganoderma lucidum-derived polysacharide on human monocytoid dendritic cells pulsed with Der p 1 allergen
<p>Abstract</p> <p>Background</p> <p><it>Ganoderma lucidum</it>-derived polysaccharide (PS-G) can rapidly and effectively promote the activation and maturation of immature dendritic cells (DCs), suggesting that PS-G possesses the capacity to regulate immune responses. This study aimed to clarify the immunologic effect of PS-G on monocyte-derived dendritic cells (MD-DCs) from asthmatic children allergic to house dust mites. The MD-DCs were stimulated for 24 h with the related allergen, Der p 1, in the presence or absence of PS-G. Cell surface markers and phagocytic capacity were assessed by FACS analysis, and key polarizing cytokines (IL-12 p40, IL-12 p70, IL-6, IL-23, and IL-10) were quantified. The subsequent regulatory effect of pulsed MD-DCs on naïve T cells was evaluated by determining the T-cell cytokine profile.</p> <p>Results</p> <p>PS-G induced the maturation of MD-DCs and decreased phagocytic capacity, even if pulsed with Der p 1. After incubation with PS-G and Der p 1, MD-DCs produced higher amounts of IL-12 p70, IL-12 p40, IL-6, IL-23, and IL10 than Der p 1-pulsed DCs. Furthermore, type 1 helper T (Th1) cell cytokine (INF-γ) production was highly increased when naïve autologous T cells were co-cultured with Der p 1-pulsed MD-DCs. Naïve T cells stimulated by MD-DCs pulsed with Der p 1 failed to produce proliferation of T-cells, whereas the addition of PS-G to Der p 1 induced a significant proliferation of T-cells similar to that observed with PS-G alone.</p> <p>Conclusion</p> <p>The presence of PS-G in an allergen pulse promoted allergic MD-DCs to produce IL-12 p70, IL-12 p40, IL-6, IL-23, and IL-10, and exerted an effect on shifting the immune balance towards Th1 in children with allergic asthma.</p
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Array atomic force microscopy for real-time multiparametric analysis.
Nanoscale multipoint structure-function analysis is essential for deciphering the complexity of multiscale biological and physical systems. Atomic force microscopy (AFM) allows nanoscale structure-function imaging in various operating environments and can be integrated seamlessly with disparate probe-based sensing and manipulation technologies. Conventional AFMs only permit sequential single-point analysis; widespread adoption of array AFMs for simultaneous multipoint study is challenging owing to the intrinsic limitations of existing technological approaches. Here, we describe a prototype dispersive optics-based array AFM capable of simultaneously monitoring multiple probe-sample interactions. A single supercontinuum laser beam is utilized to spatially and spectrally map multiple cantilevers, to isolate and record beam deflection from individual cantilevers using distinct wavelength selection. This design provides a remarkably simplified yet effective solution to overcome the optical cross-talk while maintaining subnanometer sensitivity and compatibility with probe-based sensors. We demonstrate the versatility and robustness of our system on parallel multiparametric imaging at multiscale levels ranging from surface morphology to hydrophobicity and electric potential mapping in both air and liquid, mechanical wave propagation in polymeric films, and the dynamics of living cells. This multiparametric, multiscale approach provides opportunities for studying the emergent properties of atomic-scale mechanical and physicochemical interactions in a wide range of physical and biological networks
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