963 research outputs found
Robust Adaptive Control of STATCOMs to Mitigate Inverter-Based-Resource (IBR)-Induced Oscillations
The interaction among inverter-based resources (IBRs) and power network may
cause small-signal stability issues, especially in low short-circuit grids.
Besides, the integration of static synchronous compensators (STATCOMs) in a
multi-IBR system for voltage support can deteriorate small-signal stability.
However, it is still challenging to understand the impact mechanism of STATCOMs
on IBR-induced oscillation issues and to design STATCOMs' control for damping
these oscillation issues in a multi-IBR system, due to complex system dynamics
and varying operating conditions. To tackle these challenges, this paper
proposes a novel method to reveal how STATCOMs influence IBR-induced
oscillation issues in a multi-IBR system from the viewpoint of grid strength,
which can consider varying operating conditions. Based on this proposed method,
we find critical operating conditions, wherein the system tends to be most
unstable; moreover, we demonstrate that robust small-signal stability issues of
the multi-IBR system with STATCOMs can be simplified as that of multiple
subsystems under critical operating conditions, which avoids traversing all
operating conditions and establishing system's detailed models. On this basis,
an adaptive control-parameter design method is proposed for STATCOMs to ensure
system's robust small-signal stability under varying operating conditions. The
efficacy of proposed methods is validated by a 39-node test system
A quantitative approach to shortening the levator palpebrae superioris to correct congenital ptosis in children
AIM:To develop a feasible method to correct congenital ptosis in children.METHODS: Sixty-four patients(102 eyelids)were divided into three groups based on the degree of ptosis: mild(4 mm). All patients underwent the same levator resection surgery in which the suspensory system of the LPS is retained. After capturing a standard photograph of primary position, the height of the superior palpebral margin was measured preoperatively by using Image J software to calculate its ideal height required during surgery. Postoperative outcome measures included upper eyelid margin height, degree of scleral exposure and exposure keratitis. The patients were followed-up at 1wk, 1mo and 6mo postoperatively.RESULTS: In the early postoperative period, except two cases with overcorrection, the positions of the eyelid upper margins were normal in all cases in the mild and moderate groups. Six months postoperatively, the eye with overcorrection in the moderate group showed improvement, while the eye in the mild group did not. Seven eyes in the severe group exhibited residual ptosis to varying degrees. The eyelids exhibited appropriate closing functionality; exposure keratitis was absent.CONCLUSION:Using this preoperative quantification technique to guide surgery not only provided a gauge for LPS shortening under general anesthesia, but also increased the success rate of surgery
Clinical significance of SOX9 in human non-small cell lung cancer progression and overall patient survival
<p>Abstract</p> <p>Background</p> <p>Sex determining region Y (SRY)-related high mobility groupbox 9 (SOX9) is an important transcription factor required for development, which regulates the expression of target genes in the associated pathway. The aim of this study was to describe the expression of SOX9 in human non-small cell lung cancer (NSCLC) and to investigate the association between SOX9 expression and progression of NSCLC.</p> <p>Methods</p> <p>SOX9 protein and mRNA expression in normal human pneumonocytes, lung cancer cell lines, and eight pairs of matched lung cancer tissues and their adjacent normal lung tissues were detected by Western blotting and real-time reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemistry was used to determine SOX9 protein expression in 142 cases of histologically characterized NSCLC. Statistical analyses were applied to test for prognostic and diagnostic associations.</p> <p>Results</p> <p>SOX9 in lung cancer cell lines was upregulated at both mRNA and protein levels, and SOX9 mRNA and protein were also elevated in NSCLC tissues compared with levels in corresponding adjacent non-cancerous lung tissues. Immunohistochemical analysis demonstrated a high expression of SOX9 in 74/142 (52.1%) paraffin-embedded archival lung cancer biopsies. Statistical analysis indicated that upregulation of SOX9 was significantly correlated with the histological stage of NSCLC (<it>P </it>= 0.017) and that patients with a high SOX9 level exhibited a shorter survival time (<it>P </it>< 0.001). Multivariate analysis illustrated that SOX9 upregulation might be an independent prognostic indicator for the survival of patients with NSCLC.</p> <p>Conclusions</p> <p>This work shows that SOX9 may serve as a novel and prognostic marker for NSCLC, and play a role during the development and progression of the disease.</p
Classification for Motion Game Based on EEG Sensing
Due to the sensor technology and classification algorithm, the accuracy of the EEG and the motion signal based classification system are limited. And the motion sensor based interface system cannot show userās mental activity such as engagement situation, tiredness state and so on, which are very important in education and medical care situations. In this paper, an openBCI and a Kinect sensor based motion classification system are proposed. The experiments results shown that the proposed method are out form the traditional motion or EEG based activity classification systems, and it is expected to develop a novel interactive device for the children and elders based on the integration algorithm
Vasopressin and epinephrine versus epinephrine in management of patients with cardiac arrest: a meta-analysis
Objective. A combination of vasopressin and epinephrine may be more effective than epinephrine alone in cardiopulmonary resuscitation (CPR), but evidence is lacking to make clinical recommendations. This meta-analysis compares the efficacy of vasopressin and epinephrine used together versus epinephrine alone in cardiac arrest (CA).
Methods. We searched MEDLINE and EMBASE for randomized trials comparing the efficacy of vasopressin and epinephrine versus epinephrine alone in adults with cardiac arrest. The primary outcome was the return of spontaneous circulation (ROSC) and the survival rate on admission and discharge .We also analyzed ROSC in subgroups of patients presenting with different arrest rhythms, such as asystole, pulseless electrical activity (PEA), ventricular fibrillation (VF).
Results. We analyzed 6 randomized trials out of 485 articles. We did not find evidence supporting the superiority of vasopressin and epinephrine used in combination, except for the survival rate at 24h 2.99 95% CI(1.43,6.28). No evidence supports the conclusion that vasopressin combined with epinephrine is better than epinephrine alone for ROSC, even amongst subgroups of patients.
Conclusion. This systematic review of the efficacy of vasopressin and epinephrine use found that its combined use is better for 24h survival rate but only in one study which included 122 patients. Further investigation will be needed to support the use of this combination for cardiac arrest management
Step-wise evolution of neural patterning by hedgehog signalling in chordates
In vertebrate embryos, Hedgehog (Hh) is expressed in some anterior basal plate domains and by notochord and floorplate cells, and ventral neural cells are patterned by the activities of Hh-regulated transcription factors. Hh signalling is antagonized by signals from the dorsal neural tube and loss of Hh leads to loss of ventral patterning as dorsal pattern expands. These mechanisms are critical for producing the neurons that implement motor responses to sensory inputs but understanding how they evolved has been hindered by lack of insight from commonly studied invertebrates where nervous system morphology and genetic mechanisms are non-conserved with vertebrates. The invertebrate chordate amphioxus, which expresses Hh in its notochord and floorplate, provides a window into the prevertebrate condition. We examined amphioxus neural development by manipulating Hh and downstream genes involved in neural pattern and cell identity. We show that Hh signalling regulates the differentiation of some neurons in amphioxus, including a subset of motor neurons. This demonstrates some conservation of mechanism between vertebrates and amphioxus. However, other aspects of neural patterning differ between the lineages. We suggest the complexity of Hh-dependent neural patterning in vertebrates evolved in a step-wise manner. Alongside other previously described regulatory changes, initial recruitment of Hh along the length of the axis occurred in an ancestor to the chordates to regulate the differentiation of a subset of neurons. This was followed, in the vertebrate lineage, by additional changes to the downstream gene regulatory network of transcription factors, giving Hh a broader role in dorsalāventral neural patterning
Prevalence of Clonorchis sinensis infection in dogs and cats in subtropical southern China
<p>Abstract</p> <p>Background</p> <p>Clonorchiasis, caused by <it>Clonorchis sinensis</it>, is one of the major parasitic zoonoses in China, particularly in China's southern Guangdong province where the prevalence of <it>C. sinensis </it>infection in humans is high. However, little is known of the prevalence of <it>C. sinensis </it>infection in its reservoir hosts dogs and cats. Hence, the prevalence of <it>C. sinensis </it>infection in dogs and cats was investigated in Guangdong province, China between October 2006 and March 2008.</p> <p>Results</p> <p>A total of 503 dogs and 194 cats from 13 administrative regions in Guangdong province were examined by post-mortem examination. The worms were examined, counted, and identified to species according to existing keys and descriptions. The average prevalences of <it>C. sinensis </it>infection in dogs and cats were 20.5% and 41.8%, respectively. The infection intensities in dogs were usually light, but in cats the infection intensities were more serious. The prevalences were higher in some of the cities located in the Pearl River Delta region which is the most important endemic area in Guangdong province, but the prevalences were relatively lower in seaside cities.</p> <p>Conclusions</p> <p>The present investigation revealed a high prevalence of <it>C. sinensis </it>infection in its reservoir hosts dogs and cats in China's subtropical Guangdong province, which provides relevant "base-line" data for conducting control strategies and measures against clonorchiasis in this region.</p
- ā¦