883 research outputs found
The extremal genus embedding of graphs
Let Wn be a wheel graph with n spokes. How does the genus change if adding a
degree-3 vertex v, which is not in V (Wn), to the graph Wn? In this paper,
through the joint-tree model we obtain that the genus of Wn+v equals 0 if the
three neighbors of v are in the same face boundary of P(Wn); otherwise,
{\deg}(Wn + v) = 1, where P(Wn) is the unique planar embedding of Wn. In
addition, via the independent set, we provide a lower bound on the maximum
genus of graphs, which may be better than both the result of D. Li & Y. Liu and
the result of Z. Ouyang etc: in Europ. J. Combinatorics. Furthermore, we obtain
a relation between the independence number and the maximum genus of graphs, and
provide an algorithm to obtain the lower bound on the number of the distinct
maximum genus embedding of the complete graph Km, which, in some sense,
improves the result of Y. Caro and S. Stahl respectively
Container Terminal Berth-Quay Crane Capacity Planning Based on Markov Chain
This paper constructs a berth-quay crane capacity planning model with the lowest average daily cost in the container terminal, and analyzes the influence of the number of berths and quay cranes on the terminal operation. The object of berth-quay crane capacity planning is to optimize the number of berths and quay cranes to maximize the benefits of the container terminal. A steady state probability transfer model based on Markov chain for container terminal is constructed by the historical time series of the queuing process. The current minimum time operation principle (MTOP) strategy is proposed to correct the state transition probability of the Markov chain due to the characteristics of the quay crane movement to change the service capacity of a single berth. The solution error is reduced from 7.03% to 0.65% compared to the queuing theory without considering the quay crane movement, which provides a basis for the accurate solution of the berth-quay crane capacity planning model. The proposed berth-quay crane capacity planning model is validated by two container terminal examples, and the results show that the model can greatly guide the container terminal berth-quay crane planning
EEG-based fatigue driving detection using correlation dimension
Driver fatigue is an important cause of traffic accidents and the detection of fatigue driving has been a hot issue in automobile active safety during the past decades. The purpose of this study is to develop a novel method to detect fatigue driving based on electroencephalogram (EEG). The volunteer is asked to perform simulated driving tasks under different mental state while EEG signals are acquired simultaneously from six electrodes at central, parietal and occipital lobe, including C3, C4, P3, P4, O1 and O2. Due to the non-linearity of human brain responses, correlation dimension is estimated with G-P algorithm to quantify the collected EEGs. Statistical analysis reveals significant decreases from awake to fatigue state of the correlation dimension for all the channels across 5 subjects (awake state: 3.87±0.13; fatigue state: 2.76±0.34; p< 0.05, paired t-test), which indicates that the correlation dimension is a promising parameter in detecting fatigue driving with EEGs
Computed tomography Osteoabsorptiometry: Review of bone density, mechanical strength of material and clinical application
Computed Tomography (CT) imaging is an effective non-invasive examination. It is widely used in the diagnosis of fractures, arthritis, tumor, and some anatomical characteristics of patients. The density value (Hounsfield unit, HU) of a material in computed tomography can be the same for materials with varying elemental compositions. This value depends on the mass density of the material and the degree of X-ray attenuation. Computed Tomography Osteoabsorptiometry (CTOAM) imaging technology is developed on the basis of CT imaging technology. By applying pseudo-color image processing to the articular surface, it is used to analyze the distribution of bone mineralization under the articular cartilage, evaluate the position of prosthesis implantation, track the progression of osteoarthritis, and determine the joint injury prognosis. Furthermore, this technique was combined with indentation testing to discuss the relationship between the high bone density area of the articular surface, the mechanical strength of the bone, and the anchorage stability of the implant, in addition to the study of the relationship between mechanical strength and bone density. This narrative study discusses the pre- and postoperative evaluation of medical device implantation position, orthopedic surgery, and the clinical treatment of bone injury and degeneration. It also discusses the research status of CTOAM technology in image post-processing engineering and the relationship between bone material and mechanical strength
Universal primers for HBV genome DNA amplification across subtypes: a case study for designing more effective viral primers
<p>Abstract</p> <p>Background</p> <p>The highly heterogenic characteristic of viruses is the major obstacle to efficient DNA amplification. Taking advantage of the large number of virus DNA sequences in public databases to select conserved sites for primer design is an optimal way to tackle the difficulties in virus genome amplification.</p> <p>Results</p> <p>Here we use hepatitis B virus as an example to introduce a simple and efficient way for virus primer design. Based on the alignment of HBV sequences in public databases and a program BxB in Perl script, our method selected several optimal sites for HBV primer design. Polymerase chain reaction showed that compared with the success rate of the most popular primers for whole genome amplification of HBV, one set of primers for full length genome amplification and four sets of walking primers showed significant improvement. These newly designed primers are suitable for most subtypes of HBV.</p> <p>Conclusion</p> <p>Researchers can extend the method described here to design universal or subtype specific primers for various types of viruses. The BxB program based on multiple sequence alignment not only can be used as a separate tool but also can be integrated in any open source primer design software to select conserved regions for primer design.</p
A Light Spot Humanoid Motion Paradigm Modulated by the Change of Brightness to Recognize the Stride Motion Frequency
The steady-state visual evoked potential (SSVEP)-based brain–computer interface (BCI) usually has the advantages of high information transfer rate (ITR) and no need for training. However, low frequencies, such as the human stride motion frequency, cannot easily induce SSVEP. To solve this problem, a light spot humanoid motion paradigm modulated by the change of brightness was designed in this study. The characteristics of the brain response to the motion paradigm modulated by the change of brightness were analyzed for the first time. The results showed that the designed paradigm could induce not only the high flicker frequency but also the modulation frequencies between the change of brightness and the motion in the primary visual cortex. Thus, the stride motion frequency can be recognized through the modulation frequencies by using the designed paradigm. Also, in an online experiment, this paradigm was employed to control a lower limb robot to achieve same frequency stimulation, which meant that the visual stimulation frequency was the same as the motion frequency of the robot. Also, canonical correlation analysis (CCA) was used to distinguish three different stride motion frequencies. The average accuracies of the classification in three walking speeds using the designed paradigm with the same and different high frequencies reached 87 and 95% respectively. Furthermore, the angles of the knee joint of the robot were obtained to demonstrate the feasibility of the electroencephalograph (EEG)-driven robot with same stimulation
GW25-e3199 Changes in pregnancy outcomes of hypertensive disorder complicating pregnancy in Shanghai between 2001 and 2010
The Effect of Hydroxylamine on K ATP Channels in Vascular Smooth Muscle and Underlying Mechanisms
ABSTRACT Hydroxylamine (HA) is a putative intermediate in the conversion of L-arginine to nitric oxide (NO). HA was reported to cause the relaxation of precontracted aorta strips; however, the ionic mechanisms of HA-induced vasorelaxation were not yet known. In the present study, the whole-cell patch-clamp technique was used to examine the effects of HA on ATP-sensitive K ϩ (K ATP ) currents and membrane potentials in vascular smooth muscle cells from rat mesenteric arteries and underlying mechanisms. It was found that bath-applied HA reversibly enhanced K ATP currents in a concentration-dependent fashion with an EC 50 of 54 Ϯ 3.4 M and hyperpolarized the cell membrane from Ϫ48 Ϯ 5.2 to Ϫ65 Ϯ 7.5 mV (n ϭ 6, p Ͻ 0.01). The increase in K ATP currents induced by HA was suppressed by superoxide dismutase (Ϫ380 Ϯ 45 to Ϫ160 Ϯ 20 pA, n ϭ 4, p Ͻ 0.01) and N-acetyl-L-cysteine (Ϫ385 Ϯ 55 to Ϫ150 Ϯ 16 pA, n ϭ 5, p Ͻ 0.01), indicating the involvement of different free radicals, including superoxide anion. Hypoxanthine/xanthine oxidase increased not only basal K ATP currents, but also HAenhanced K ATP currents (from Ϫ355 Ϯ 40 to Ϫ480 Ϯ 62 pA, n ϭ 6, p Ͻ 0.05). Sodium nitroprusside, a spontaneous NO donor, and a membrane-permeable cGMP analog (8-bromocGMP) were without effects on HA-enhanced K ATP currents or basal K ATP currents. Our results indicate that HA augmented K ATP channel activity and hyperpolarized cell membrane, possibly via increased free radical generation
Expression of apolipoprotein M in human hepatocellular carcinoma tissues
The present study examined mRNA levels and protein mass of apolipoprotein M (apoM) in human hepatocellular carcinoma (HCC) tissues and in the adjacent tissues. Plasma apoM levels in these HCC patients were also determined and compared to the normal subjects. The mean level of plasma apoM in the HCC patients was 0.61 +/- 0.30 OD mm(-2), which was significantly higher than that in the normal subjects 0.37 +/- 0.07 OD mm(-2) (P < 0.01). However, both apoM mRNA levels and apoM protein mass in the HCC tissues were significantly lower than in the adjacent tissues (P < 0.05). It is concluded that human hepatocellular carcinoma tissues had a reduced capacity to produce apoM than the adjacent non-tumor tissues. However, the plasma apoM levels were higher in the HCC patients than in normal subjects, which suggested that tissues adjacent to the tumors or extra-hepatic apoM production in the HCC patients may contribute to the higher plasma apoM levels in these patients. The clinical significance of apoM in relation to HCC still needs further investigation. (C) 2009 Published by Elsevier GmbH
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