Robust power system stabilizer design for an industrial power system in Taiwan using linear matrix inequality techniques

[[abstract]]This work proposes the design of robust power system stabilizers (PSS) for the supplementary damping of the largest industrial power system in Taiwan. The design procedure integrates several existing robust control techniques, including the linear matrix inequality (LMI) framework, the mixed-sensitivity formulation and model-order reductions. The selection of weighting function for shaping the open loop control will also be considered. Nonlinear power system transient simulations incorporating with various faults are also performed to confirm the effectiveness of the proposed design. Simulation results have demonstrated that the resulting robust PSS can indeed enhance the damping of the low-frequency oscillations and improve system performance specifications in both the frequency domain and the time domain.[[conferencetype]]國際[[conferencedate]]20040606~20040610[[booktype]]紙本[[conferencelocation]]Denver, CO, US

Plasma levels in sepsis patients of annexin A1, lipoxin A4, macrophage inflammatory protein-3a, and neutrophil gelatinase-associated lipocalin

AbstractBackgroundThe relationship between the various cytokine responses that occur during sepsis remains controversial. Emerging evidence indicates that the proinflammatory and anti-inflammatory responses are regulated simultaneously from the beginning of sepsis. However, the roles of the novel anti-inflammatory mediators annexin (Anx)A1 and lipoxin (LX)A4 and the proinflammatory cytokines neutrophil gelatinase-associated lipocalin (NGAL) and macrophage inflammatory protein (MIP)-3a have been studied.MethodsIn this study, the plasma levels of AnxA1, LXA4, NGAL, MIP-3a, interleukin (IL)-8 and IL-6 in patients with sepsis were determined on admission to the intensive care unit. The patients were classified into survivors and non-survivors based on their outcome on day 28.ResultsAnxA1 and LXA4 levels were decreased in sepsis patients compared with control patients, whereas the levels of the proinflammatory cytokines MIP-3a, NGAL, IL-8, and IL-6 were elevated. Furthermore, a significantly higher level of MIP-3a was detected in nonsurviving patients compared with surviving patients (p < 0.05), whereas there were no significant differences between these two groups for the levels of the other mediators. Correlation analysis demonstrated that only NGAL level was closely correlated with the level of IL-6. Univariate analysis indicated that the levels of MIP-3a and IL-8 were independent factors associated with patient survival, but this was not confirmed by the multivariate analysis.ConclusionAnxA1 and LXA4 plasma levels were found to be decreased in sepsis patients, whereas the levels of MIP-3a and NGAL were found to be elevated. This warrants further study in order to determine the clinical implications of these changes

Genetic population structure of the alpine species Rhododendron pseudochrysanthum sensu lato (Ericaceae) inferred from chloroplast and nuclear DNA

<p>Abstract</p> <p>Background</p> <p>A complex of incipient species with different degrees of morphological or ecological differentiation provides an ideal model for studying species divergence. We examined the phylogeography and the evolutionary history of the <it>Rhododendron pseudochrysanthum </it>s. l.</p> <p>Results</p> <p>Systematic inconsistency was detected between gene genealogies of the cpDNA and nrDNA. Rooted at <it>R. hyperythrum </it>and <it>R. formosana</it>, both trees lacked reciprocal monophyly for all members of the complex. For <it>R. pseudochrysanthum </it>s.l., the spatial distribution of the cpDNA had a noteworthy pattern showing high genetic differentiation (F_ST= 0.56-0.72) between populations in the Yushan Mountain Range and populations of the other mountain ranges.</p> <p>Conclusion</p> <p>Both incomplete lineage sorting and interspecific hybridization/introgression may have contributed to the lack of monophyly among <it>R. hyperythrum</it>, <it>R. formosana </it>and <it>R. pseudochrysanthum </it>s.l. Independent colonizations, plus low capabilities of seed dispersal in current environments, may have resulted in the genetic differentiation between populations of different mountain ranges. At the population level, the populations of Central, and Sheishan Mountains may have undergone postglacial demographic expansion, while populations of the Yushan Mountain Range are likely to have remained stable ever since the colonization. In contrast, the single population of the Alishan Mountain Range with a fixed cpDNA haplotype may have experienced bottleneck/founder's events.</p

Enzyme-mediated stiffening hydrogels for probing activation of pancreatic stellate cells

The complex network of biochemical and biophysical cues in the pancreatic desmoplasia not only presents challenges to the fundamental understanding of tumor progression, but also hinders the development of therapeutic strategies against pancreatic cancer. Residing in the desmoplasia, pancreatic stellate cells (PSCs) are the major stromal cells affecting the growth and metastasis of pancreatic cancer cells by means of paracrine effects and extracellular matrix protein deposition. PSCs remain in a quiescent/dormant state until they are 'activated' by various environmental cues. While the mechanisms of PSC activation are increasingly being described in literature, the influence of matrix stiffness on PSC activation is largely unexplored. To test the hypothesis that matrix stiffness affects myofibroblastic activation of PSCs, we have prepared cell-laden hydrogels capable of being dynamically stiffened through an enzymatic reaction. The stiffening of the microenvironment was created by using a peptide linker with additional tyrosine residues, which were susceptible to tyrosinase-mediated crosslinking. Tyrosinase catalyzes the oxidation of tyrosine into dihydroxyphenylalanine (DOPA), DOPA quinone, and finally into DOPA dimer. The formation of DOPA dimer led to additional crosslinks and thus stiffening the cell-laden hydrogel. In addition to systematically studying the various parameters relevant to the enzymatic reaction and hydrogel stiffening, we also designed experiments to probe the influence of dynamic matrix stiffening on cell fate. Protease-sensitive peptides were used to crosslink hydrogels, whereas integrin-binding ligands (e.g., RGD motif) were immobilized in the network to afford cell-matrix interaction. PSC-laden hydrogels were placed in media containing tyrosinase for 6h to achieve in situ gel stiffening. We found that PSCs encapsulated and cultured in a stiffened matrix expressed higher levels of αSMA and hypoxia-inducible factor 1α (HIF-1α), suggestive of a myofibroblastic phenotype. This hydrogel platform offers a facile means of in situ stiffening of cell-laden matrices and should be valuable for probing cell fate process dictated by dynamic matrix stiffness. STATEMENT OF SIGNIFICANCE: Hydrogels with spatial-temporal controls over crosslinking kinetics (i.e., dynamic hydrogel) are increasingly being developed for studying mechanobiology in 3D. The general principle of designing dynamic hydrogel is to perform cell encapsulation within a hydrogel network that allows for postgelation modification in gel crosslinking density. The enzyme-mediated in situ gel stiffening is innovative because of the specificity and efficiency of enzymatic reaction. Although tyrosinase has been used for hydrogel crosslinking and in situ cell encapsulation, to the best of our knowledge tyrosinase-mediated DOPA formation has not been explored for in situ stiffening of cell-laden hydrogels. Furthermore, the current work provides a gradual matrix stiffening strategy that may more closely mimic the process of tumor development

Chinese Herbal Medicine Therapy and the Risk of Mortality for Chronic Hepatitis B Patients with Concurrent Liver Cirrhosis: a Nationwide Population-Based Cohort Study

Chronic hepatitis B (CHB) is increasingly recognized as a public health problem in Taiwan. After affected patients are diagnosed with contaminant liver cirrhosis (LC), adverse clinical outcomes, especially death, are common. This study aimed to investigate the effect of Chinese herbal medicine (CHM), an essential branch of Traditional Chinese medicine (TCM), on the mortality risk among CHB patients with contaminant LC. This longitudinal cohort study used the Taiwanese National Health Insurance Research Database to identify 1522 patients 20–70 years of age with newly diagnosed CHB with LC during 1998–2007. Among them, 508 (33.37%) had received CHM products after the onset of CHB (CHM users), and the remaining 1014 patients (66.63%) were designated as a control group (non-CHM users). All enrollees were followed until the end of 2012 to determine deaths during the study period. We applied the Cox proportional hazards regression model to compute the hazard ratio for the association of CHM use and the subsequent risk of death. During the follow-up period, 156 CHM users and 493 non-CHM users died. After controlling for potential confounders, CHM users were found to have a significantly reduced risk of death compared with non-CHM users by 56%, and the effect was predominantly observed among those treated with CHM for \u3e 180 days. CHM therapy lowered the risk of death among CHB patients with contaminant LC, which supported CHM might provide further treatment options for those with chronic liver diseases

The relationship between gallbladder status and recurrent biliary complications in patients with choledocholithiasis following endoscopic treatment

AbstractBackgroundEndoscopic methods are currently the treatment of choice for patients with common bile duct (CBD) stones, but subsequent management of the intact gallbladder for patients following endoscopic treatment is still controversial. The primary aim of this study was to discover the association between gallbladder status and recurrent biliary complications for patients with CBD stones after endoscopic treatment. Additionally, we also sought to determine risk factors for recurrent biliary complications in these patients.MethodsThe records of 1625 patients with CBD stones following endoscopic treatment were reviewed. A total of 681 patients were enrolled and subsequently categorized into four groups: Group 1 (n = 201), calculous gallbladder; Group 2 (n = 140), acalculous gallbladder; Group 3 (n = 175), elective cholecystectomy after endoscopic treatment; and Group 4 (n = 165), prior cholecystectomy. The basic demographics and recurrent biliary complications during follow-up among these four groups were analyzed by Chi-square test, ANOVA, Kaplan-Meier analysis, and log-rank test.ResultsDuring the median follow-up period of 34 months, 133 patients (20%) with recurrent biliary complications were identified. The recurrence rates of Groups 1, 2, 3, and 4 were 29%, 11%, 15%, and 19%, respectively. Kaplan-Meier analysis showed that patients with calculous gallbladder had a significantly higher rate of recurrent biliary complication. In multivariate analysis, patients with a history of cirrhosis, juxta-papillary diverticulum, calculous gallbladder, CBD size ≥1.5 cm, and endoscopic management with endoscopic sphincterotomy were at a higher risk for developing biliary complications (p = 0.029, p = 0.039, p < 0.001, p = 0.002, p = 0.021, respectively.)ConclusionPatients with cholecystolithiasis and CBD stones had a higher incidence of recurrent biliary complications. For some of these patients, elective cholecystectomy following endoscopic treatment may be considered. However, routine elective cholecystectomy in patients with normal gallbladder is not appropriate because of the low recurrence of biliary complications. Whether gallbladder function affects the biliary clearance and biliary complications requires further research

Intra-articular injections of sodium hyaluronate (Hyalgan®) in osteoarthritis of the knee. a randomized, controlled, double-blind, multicenter trial in the asian population

<p>Abstract</p> <p>Background</p> <p>The efficacy and tolerability of 500-730 kDa sodium hyaluronate (Hyalgan^®) for treatment of osteoarthritis (OA) pain has been established in clinical trials, but few data are available in the Asian population. We conducted a randomized, double-blind, multicenter, placebo-controlled study to evaluate the efficacy and tolerability of this preparation in a Taiwanese population.</p> <p>Methods</p> <p>Two hundred patients with mild to moderate OA of the knee were randomized to receive five weekly intra-articular injections of sodium hyaluronate or placebo. The primary efficacy outcome was the change from baseline to Week 25 in patients' evaluation of pain using a 100-mm visual analog scale (VAS) during the 50-foot walking test. Additional outcomes included Western Ontario and McMaster Universities (WOMAC) scores, time on the 50-foot walking test, patient's and investigator's subjective assessment of effectiveness, acetaminophen consumption, and the amounts of synovial fluid.</p> <p>Results</p> <p>The Hyalgan^®treatment group showed a significantly greater improvement from baseline to Week 25 in VAS pain on the 50-foot walking test than the placebo group (p = 0.0020). The Hyalgan^®group revealed significant improvements from baseline to week 25 in WOMAC pain and function score than the placebo group (p = 0.005 and 0.0038, respectively) Other outcomes, such as time on the 50-foot walking test and subjective assessment of effectiveness, did not show any significant difference between groups. Both groups were safe and well tolerated.</p> <p>Conclusions</p> <p>The present study suggests that five weekly intra-articular injections of sodium hyaluronate are well tolerated, can provide sustained relief of pain, and can improve function in Asian patients with osteoarthritis of the knee.</p> <p>Level of Evidence</p> <p>Therapeutic study, Level I-1a (randomized controlled trial with a significant difference).</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01319461">NCT01319461</a></p

The influence of serotonin transporter polymorphisms on cortical activity: A resting EEG study

<p>Abstract</p> <p>Background</p> <p>The serotonin transporter gene (<it>5-HTT</it>) is a key regulator of serotonergic neurotransmission and has been linked to various psychiatric disorders. Among the genetic variants, polymorphisms in the <it>5-HTT </it>gene-linked polymorphic region (<it>5-HTTLPR</it>) and variable-number-of-tandem-repeat in the second intron (<it>5-HTTVNTR</it>) have functional consequences. However, their genetic impact on cortical oscillation remains unclear. This study examined the modulatory effects of <it>5-HTTLPR </it>(L-allele carriers vs. non-carriers) and <it>5-HTTVNTR </it>(10-repeat allele carriers vs. non-carriers) polymorphism on regional neural activity in a young female population.</p> <p>Methods</p> <p>Blood samples and resting state eyes-closed electroencephalography (EEG) signals were collected from 195 healthy women and stratified into 2 sets of comparisons of 2 groups each: L-allele carriers (<it>N </it>= 91) vs. non-carriers for <it>5-HTTLPR </it>and 10-repeat allele carriers (<it>N </it>= 25) vs. non-carriers for <it>5-HTTVNTR</it>. The mean power of 18 electrodes across theta, alpha, beta, gamma, gamma1, and gamma2 frequencies was analyzed. Between-group statistics were performed by an independent t-test, and global trends of regional power were quantified by non-parametric analyses.</p> <p>Results</p> <p>Among <it>5-HTTVNTR </it>genotypes, 10-repeat allele carriers showed significantly low regional power at gamma frequencies across the brain. We noticed a consistent global trend that carriers with low transcription efficiency of 5-HTT possessed low regional powers, regardless of frequency bands. The non-parametric analyses confirmed this observation, with <it>P </it>values of 3.071 × 10^-8and 1.459 × 10^-12for <it>5-HTTLPR </it>and <it>5-HTTVNTR</it>, respectively.</p> <p>Conclusions and Limitations</p> <p>Our analyses showed that genotypes with low 5-HTT activity are associated with less local neural synchronization during relaxation. The implication with respect to genetic vulnerability of 5-HTT across a broad range of psychiatric disorders is discussed. Given the low frequency of 10-repeat allele of <it>5-HTTVNTR </it>in our research sample, the possibility of false positive findings should also be considered.</p

Isotretinoin Oil-Based Capsule Formulation Optimization

The purpose of this study was to develop and optimize an isotretinoin oil-based capsule with specific dissolution pattern. A three-factor-constrained mixture design was used to prepare the systemic model formulations. The independent factors were the components of oil-based capsule including beeswax (X1), hydrogenated coconut oil (X2), and soybean oil (X3). The drug release percentages at 10, 30, 60, and 90 min were selected as responses. The effect of formulation factors including that on responses was inspected by using response surface methodology (RSM). Multiple-response optimization was performed to search for the appropriate formulation with specific release pattern. It was found that the interaction effect of these formulation factors (X1X2, X1X3, and X2X3) showed more potential influence than that of the main factors (X1, X2, and X3). An optimal predicted formulation with Y10 min, Y30 min, Y60 min, and Y90 min release values of 12.3%, 36.7%, 73.6%, and 92.7% at X1, X2, and X3 of 5.75, 15.37, and 78.88, respectively, was developed. The new formulation was prepared and performed by the dissolution test. The similarity factor f2 was 54.8, indicating that the dissolution pattern of the new optimized formulation showed equivalence to the predicted profile