Doctor of Philosophy

dissertationWe study the geometry of higher dimensional algebraic varieties according to the dichotomy of Kodaira dimensions, negative or nonnegative, and the corresponding pictures in the Minimal Model Conjecture. On the one hand, according to the Minimal Model Conjecture, a variety with nonnegative Kodaira dimension is birational to a minimal model, which has semiample canonical class. This has been done if dimension is less than or equal to three and for varieties of general type in any dimension. In general, the Minimal Model Conjecture is still open. As the first result, we show that the Minimal Model Conjecture for varieties with nonnegative Kodaira dimensions follows from the Minimal Model Conjecture for varieties with Kodaira dimension zero. In particular, the Minimal Model Conjecture is reduced to the Minimal Model Conjecture for varieties of Kodaira dimension zero and the Nonvanishing Conjecture. On the other hand, according to the Minimal Model Conjecture, Fano varieties of Picard number one are the building blocks for varieties with negative Kodaira dimension. The set of mildly singular Fano varieties of given dimension is expected to be bounded. As a second result, we exhibit an effective upper bound of the anticanonical volume for the set of e-klt Q-factorial log Q-Fano threefolds with Picard number one. This result is related to a conjecture open in dimension three and higher, the Borisov-Alexeev-Borisov Conjecture, which asserts boundedness of the set of e-klt log Q-Fano varieties. In the end of this dissertation, we include some partial results of the Nonvanishing Conjecture in the minimal model program. The minimal model program is developed to attack the Minimal Model Conjecture. The Nonvanishing Conjecture is one of the most important missing ingredient for completing the minimal model program

Nanoscale modification of porous gelatin scaffolds with chondroitin sulfate for corneal stromal tissue engineering

Recent studies reflect the importance of using naturally occurring biopolymers as three-dimensional corneal keratocyte scaffolds and suggest that the porous structure of gelatin materials may play an important role in controlling nutrient uptake. In the current study, the authors further consider the application of carbodiimide cross-linked porous gelatin as an alternative to collagen for corneal stromal tissue engineering. The authors developed corneal keratocyte scaffolds by nanoscale modification of porous gelatin materials with chondroitin sulfate (CS) using carbodiimide chemistry. Scanning electron microscopy/energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy showed that the amount of covalently incorporated polysaccharide was significantly increased when the CS concentration was increased from 0% to 1.25% (w/v). In addition, as demonstrated by dimethylmethylene blue assays, the CS content in these samples was in the range of 0.078–0.149 nmol per 10 mg scaffold. When compared with their counterparts without CS treatment, various CS-modified porous gelatin membranes exhibited higher levels of water content, light transmittance, and amount of permeated nutrients but possessed lower Young’s modulus and resistance against protease digestion. The hydrophilic and mechanical properties of scaffolds modified with 0.25% CS were comparable with those of native corneas. The samples from this group were biocompatible with the rabbit corneal keratocytes and showed enhanced proliferative and biosynthetic capacity of cultured cells. In summary, the authors found that the nanoscale-level modification has influence on the characteristics and cell-material interactions of CS-containing gelatin hydrogels. Porous membranes with a CS content of 0.112 ± 0.003 nmol per 10 mg scaffold may hold potential for use in corneal stromal tissue engineering

On character table of Clifford groups

Based on a presentation of $\mathcal{C}_n$ and the help of [GAP], we construct the character table of the Clifford group $\mathcal{C}_n$ for $n=1,2,3$. As an application, we can efficiently decompose the (higher power of) tensor product of the matrix representation in those cases. Our results recover some known results in [HWW, WF] and reveal some new phenomena. We prove that the trivial character is the only linear character for $\mathcal{C}_n$ and hence $\mathcal{C}_n$ equals to its commutator subgroup when $n\geq 3$. A few conjectures about $\mathcal{C}_n$ for general $n$ are proposed.Comment: 13 pages; comments and suggestions are welcom

Promoter methylation of the hMLH1 gene and protein expression of human mutL homolog 1 and human mutS homolog 2 in resected esophageal squamous cell carcinoma

ObjectiveAberrant expression of mismatch repair genes, such as human mutL homolog 1 (hMLH1) and human mutS homolog 2 (hMSH2), are common in some human cancers, and promoter methylation is believed to inactivate expression of hMLH1. We investigated whether promoter methylation is involved in loss of hMLH1 protein and whether aberrant expression of hMLH1 and hMSH2 protein is related to prognosis after resection for esophageal squamous cell cancer.MethodsWe analyzed promoter methylation of hMLH1 using methylation-specific polymerase chain reaction and hMLH1 and hMSH2 protein by using immunohistochemistry in 60 resected tumor specimens. The Pearson χ2 test was used to compare expression of hMLH1 and hMSH2 protein among patients with different clinicopathologic parameters. Concordance analysis was performed between hMLH1 methylation and its protein expression.ResultsLoss of hMLH1 and hMSH2 protein was found in 43 (72%) and 39 (65%, P = .06) of 60 resected specimens, respectively. hMLH1 protein correlated well with tumor staging (P < .0001), depth of tumor invasion (P = .008), and nodal involvement (P < .0001) but not with distant metastasis, whereas hMSH2 did not show correlation with any of these parameters. A concordance rate of 83.3% was present between expression of hMLH1 protein and its promoter methylation (P < .001).ConclusionsAberrant expression of hMLH1 and hMSH2 protein is frequently associated with the presence of esophageal squamous cell carcinoma, and expression of hMLH1 protein is a better prognostic predictor than is expression of hMSH2 protein. Promoter methylation is one of the mechanisms responsible for loss of hMLH1 protein in esophageal squamous cell cancer

A 64-week, multicenter, open-label study of aripiprazole effectiveness in the management of patients with schizophrenia or schizoaffective disorder in a general psychiatric outpatient setting

<p>Abstract</p> <p>Objective</p> <p>To evaluate the overall long-term effectiveness of aripiprazole in patients with schizophrenia in a general psychiatric practice setting in Taiwan.</p> <p>Methods</p> <p>This was a prospective, open-label, multicenter, post-market surveillance study in Taiwanese patients with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) diagnosis of schizophrenia or schizoaffective disorder requiring a switch in antipsychotic medication because current medication was not well tolerated and/or clinical symptoms were not well controlled. Eligible patients were titrated to aripiprazole (5-30 mg/day) over a 12-week switching phase, during which their previous medication was discontinued. Patients could then enter a 52-week, long-term treatment phase. Aripiprazole was flexibly dosed (5-30 mg/day) at the discretion of the treating physicians. Efficacy was assessed using the Clinical Global Impression scale Improvement (CGI-I) score, the Clinical Global Impression scale Severity (CGI-S) score, The Brief Psychiatry Rating Scale (BPRS), and the Quality of Life (QOL) scale, as well as Preference of Medicine (POM) ratings by patients and caregivers. Safety and tolerability were also assessed.</p> <p>Results</p> <p>A total of 245 patients were enrolled and switched from their prior antipsychotic medications, and 153 patients entered the 52-week extension phase. In all, 79 patients (32.2%) completed the study. At week 64, the mean CGI-I score was 3.10 and 64.6% of patients who showed response. Compared to baseline, scores of CGI-S, QOL, and BPRS after 64 weeks of treatment also showed significant improvements. At week 12, 65.4% of subjects and 58.9% of caregivers rated aripiprazole as better than the prestudy medication on the POM. The most frequently reported adverse events (AEs) were headache, auditory hallucinations and insomnia. A total of 13 patients (5.3%) discontinued treatment due to AEs. No statistically significant changes were noted with respect to fasting plasma glucose, lipid profile, body weight, and body mass index after long-term treatment with aripiprazole.</p> <p>Conclusions</p> <p>Although the discontinuation rate was high, aripiprazole was found to be effective, safe and well tolerated in the long-term treatment of Taiwanese patients with schizophrenia who continued to receive treatment for 64 weeks.</p