720 research outputs found
Two nonmonotone multiobjective memory gradient algorithms
In this paper, two types of nonmonotone memory gradient algorithm for solving
unconstrained multiobjective optimization problems are introduced. Under some
suitable conditions, we show the convergence of the full sequence generated by
the proposed algorithms to a weak Pareto optimal poin
Motor neuron-derived Thsd7a is essential for zebrafish vascular development via the Notch-dll4 signaling pathway.
BackgroundDevelopment of neural and vascular systems displays astonishing similarities among vertebrates. This parallelism is under a precise control of complex guidance signals and neurovascular interactions. Previously, our group identified a highly conserved neural protein called thrombospondin type I domain containing 7A (THSD7A). Soluble THSD7A promoted and guided endothelial cell migration, tube formation and sprouting. In addition, we showed that thsd7a could be detected in the nervous system and was required for intersegmental vessels (ISV) patterning during zebrafish development. However, the exact origin of THSD7A and its effect on neurovascular interaction remains unclear.ResultsIn this study, we discovered that zebrafish thsd7a was expressed in the primary motor neurons. Knockdown of Thsd7a disrupted normal primary motor neuron formation and ISV sprouting in the Tg(kdr:EGFP/mnx1:TagRFP) double transgenic zebrafish. Interestingly, we found that Thsd7a morphants displayed distinct phenotypes that are very similar to the loss of Notch-delta like 4 (dll4) signaling. Transcript profiling further revealed that expression levels of notch1b and its downstream targets, vegfr2/3 and nrarpb, were down-regulated in the Thsd7a morphants. These data supported that zebrafish Thsd7a could regulate angiogenic sprouting via Notch-dll4 signaling during development.ConclusionsOur results suggested that motor neuron-derived Thsd7a plays a significant role in neurovascular interactions. Thsd7a could regulate ISV angiogenesis via Notch-dll4 signaling. Thus, Thsd7a is a potent angioneurin involved in the development of both neural and vascular systems
THE REGULATION OF LEG STIFFNESS AND EMG ACTIVITIES ON PERSON WITH VISUAL IMPAIRED DURING STEP-DOWN WALKING
The purpose of present study was to evaluate leg muscular regulation and neuromuscular activation by investigating the stiffness and EMG amplitude of normal vision students and visually impaired students. 10 normal vision (age: 24.3±20 years; height: 171.5±4.6cm; mass: 65.9±8.0kg) and 10 visually impaired students (age: 23.2±2.4 years; height: 163.4±9.6cm; mass: 62.8±15.0kg) were served as subjects. AMTI force platform (1200 Hz), Peak Performance motion analysis system (60Hz) and Biovision EMG system were used synchronously to record the ground reaction force, the kinematic parameters and EMG signals of lower extremity during the subjects stepped down from height 20, 30 and 40cm. The results revealed that the regulation of neuromuscular system of the impaired is less efficient compared to the normal one because of lower muscle stiffness and EMG activity
Senile cataracts and oxidative stress
AbstractIn numerous epidemiological and animal models, it can be inferred that oxidative stress is a key factor in cataract formation. Production of reactive oxygen species and reduction of endogenous antioxidants both contribute to cataract formation. In the cataractogenous process, lens proteins lose sulfhydryl groups and become thiolated or cross-linked by disulfide bonds. The resultant high molecular weight aggregates become insoluble and affect lens transparency. All these are consequences of changes in the redox state. A mixed protein-thiol and protein-protein disulfide bond precedes the morphological changes of cataract. Normally, sustained high levels of reduced glutathione provide a protective effect, while depletion of glutathione causes damage to epithelial cells and fiber cells. UV rays in the ambient environment evoke reactive oxygen species formation and also contribute to cataracts. The reduction in free UV filters and increase in their binding to lens proteins make the lens more predisposed to UV damage and oxidation. In the aqueous humor of cataract lenses, there is a decrease in antioxidant enzymes and increase in nitric oxide, which demonstrates the relationship between oxidative stress and cataracts. Though surgical intervention is the standard treatment for cataracts, experimental medical therapies for cataracts are under extensive investigation. Carnosine, a pro-drug of carnosine-N-acetylcarnosine, bendazac, ascorbic acid, and aldose reductase inhibitors are under therapeutic evaluation, and prevention of cataract formation may be possible in the future
Optical Forces in Coupled Chiral Particles
Structural chirality can induce counter-intuitive optical forces due to
inherent symmetry properties. While optical forces on a single chiral particle
in the Rayleigh regime have been well studied, optical forces in coupled chiral
particles remain less explored. By using full-wave numerical simulations and
analytical methods of source representation and coupled mode theory, we
investigated the optical forces induced by a plane wave on two chiral particles
coupling with each other via the evanescent near fields. We found that the
induced electric and magnetic dipoles of the chiral particles have complicated
couplings that give rise to dark and bright modes. The interaction force
between the particles can be either attractive or repulsive, and its magnitude
can be significantly enhanced by the resonance modes. The attractive force is
much stronger if two particles are of opposite handedness compared with the
case of same handedness. The electric dipole force and the magnetic dipole
force have the same sign for two particles with the same handedness, while they
are of different signs for two particles with opposite handedness. The results
can lead to a better understanding of chirality-induced optical forces with
potential applications in optical manipulations and chiral light-matter
interactions.Comment: 11 pages, 13 figure
A panel of tumor markers, calreticulin, annexin A2, and annexin A3 in upper tract urothelial carcinoma identified by proteomic and immunological analysis
BACKGROUND: Upper tract urothelial carcinoma (UTUC) is a tumor with sizable metastases and local recurrence. It has a worse prognosis than bladder cancer. This study was designed to investigate the urinary potential tumor markers of UTUC. METHODS: Between January 2008 and January 2009, urine was sampled from 13 patients with UTUC and 20 healthy adults. The current study identified biomarkers for UTUC using non-fixed volume stepwise weak anion exchange chromatography for fractionation of urine protein prior to two-dimensional gel electrophoresis. RESULTS: Fifty five differential proteins have been determined by comparing with the 2-DE maps of the urine of UTUC patients and those of healthy people. Western blotting analysis and immunohistochemistry of tumor tissues and normal tissues from patients with UTUC were carried out to further verify five possible UTUC biomarkers, including zinc-alpha-2-glycoprotein, calreticulin, annexin A2, annexin A3 and haptoglobin. The data of western blot and immunohistochemical analysis are consistent with the 2-DE data. Combined the experimental data in the urine and in tumor tissues collected from patients with UTUC, the crucial over-expressed proteins are calreticulin, annexin A2, and annexin A3. CONCLUSIONS: Calreticulin, annexin A2, and annexin A3 are very likely a panel of biomarkers with potential value for UTUC diagnosis
Inhibitory Effects of Ketamine on Lipopolysaccharide-Induced Microglial Activation
Microglia activated in response to brain injury release neurotoxic factors including nitric oxide (NO) and proinflammatory cytokines such as tumor necrosis factor-α
(TNF-α) and interleukin-1β (IL-1β). Ketamine, an anesthetic induction agent, is generally reserved for use in patients with severe hypotension or respiratory depression. In this study, we found that ketamine (100 and 250 μM) concentration-dependently inhibited lipopolysaccharide (LPS)-induced NO and IL-1β release in primary cultured microglia. However, ketamine (100 and 250 μM) did not significantly inhibit the LPS-induced TNF-α production in microglia, except at the higher concentration (500 μM). Further study of the molecular mechanisms revealed that ketamine markedly inhibited extracellular signal-regulated kinase (ERK1/2) phosphorylation but not c-Jun N-terminal kinase or p38 mitogen-activated protein kinase stimulated by LPS in microglia. These results suggest that microglial inactivation by ketamine is at least partially due to inhibition of ERK1/2 phosphorylation
Bifurcation and hysteresis of flow pattern transition in a shallow molten silicon pool with Cz configuration
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Using optical code-division multiple-access techniques in Michelson interferometer vibration sensor networks
This study proposes a spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) framework for accessing the vibration frequency of a test object by using a Michelson interferometer vibration sensor (MIVS). Each sensor node possesses an individual signature codeword, and liquid crystal spatial light modulator (LC-SLM) encoders/decoders (codecs) are adopted to provide excellent orthogonal properties in the frequency domain. The proposed LC-SLM-based OCDMA system mitigates multiple access interference among all sensor nodes. When optical beams strike and are reflected by the object, the sensing interferometer becomes sensitive to external physical parameters such as temperature, strain, and vibration. The MIVS includes a Michelson interferometer placed at a specific distance from the test object on a designed vibration platform. A balanced photodetector (BPD) was used to convert the light output of the LC-SLM decoders into electrical signals, and a digitizing oscilloscope was used to Fourier transform the BPD electrical signal output, thereby yielding the vibration frequency of the test object. The results showed that the proposed sensor network with an interferometer can be used as a distributed highly sensitive sensor to obtain mechanical values. This study provides a new optical sensor network for current vibration frequency measurements
Effects of High-tech Corporate Characteristics on Social Capital and Role of Human Resource Management
Human resource is the major source of competitive advantages for an enterprise. Discussions aiming at the role of human resource in educational communities are progressing in past years. From the mobility of human resource in an organization, retaining human assets or reducing the mobility to the lowest are considered as the professional commitment of human resource and the direction for efforts. A new viewpoint about the role of human resource reveals that the role of human resource is to change social capital into the driving force of competitive advantages of an organization. It might affect the presentation of different roles of human resource in various corporate characteristics. For this reason, the effects of high-tech corporate characteristics on social capital and role of human resource management are discussed in this study.
Aiming at Kunshan High-tech Industrial Development Zone, the management and the employees in the manufacturers are distributed 1000 copies of questionnaires, and 683 valid copies are retrieved, with the retrieval rate 68%. The research results show 1. significantly positive effects of social capital on the role of human resource, 2. remarkably positive effects of corporate characteristics on social capital, and 3. notably positive effects of corporate characteristics on the role of human resource. It is expected to verify richer and more diverse effects for the reference of successive research and practice communities
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