258 research outputs found
Optimal financing and dividend distribution in a general diffusion model with regime switching
We study the optimal financing and dividend distribution problem with
restricted dividend rates in a diffusion type surplus model where the drift and
volatility coefficients are general functions of the level of surplus and the
external environment regime. The environment regime is modeled by a Markov
process. Both capital injections and dividend payments incur expenses. The
objective is to maximize the expectation of the total discounted dividends
minus the total cost of capital injections. We prove that it is optimal to
inject capitals only when the surplus tends to fall below zero and to pay out
dividends at the maximal rate when the surplus is at or above the threshold
dependent on the environment regime
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CELLCOUNTER: Novel Open-Source Software for Counting Cell Migration and Invasion In Vitro
Transwell Boyden chamber based migration/invasion assay is a simple and extensively used approach for the characterization of cell motility in vitro. Cell motility is quantified by counting the number of cells that pass through the filter membrane. The counting is usually performed manually, which is laborious and error prone. We have therefore developed CELLCOUNTER, an application that is capable of recognizing and counting the total number of cells through an intuitive graphical user interface. The counting can be performed in batch, and the counting results can be visualized and further curated manually. CELLCOUNTER will be helpful in streamlining the experimental process and improving the reliability of the data acquisition
Synthesis, characterization and molecular docking studies of novel S-substituted phenacyl-1,3,4-thiadiazole-thiol derivatives as antimicrobial agents
In the present study, synthesis and antimicrobial activity of 2,5-disubstituted 1,3,4-thiadiazole derivatives 5a-f are described. The structures of the newly synthesized compounds were confirmed by FT-IR, 1H NMR, 13C NMR, mass and elemental analysis. All compounds were screened for antitubercular and antimicrobial activity. Molecular modeling studies were performed to dock compounds into the ecKAS III binding site, which suggested probable inhibition mechanism. The results revealed that most of the compounds showed high to moderate biological activity against tested microorganisms
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Production of Glycopeptide Derivatives for Exploring Substrate Specificity of Human OGA Toward Sugar Moiety.
O-GlcNAcase (OGA) is the only enzyme responsible for removing N-acetyl glucosamine (GlcNAc) attached to serine and threonine residues on proteins. This enzyme plays a key role in O-GlcNAc metabolism. However, the structural features of the sugar moiety recognized by human OGA (hOGA) remain unclear. In this study, a set of glycopeptides with modifications on the GlcNAc residue, were prepared in a recombinant full-length human OGT-catalyzed reaction, using chemoenzymatically synthesized UDP-GlcNAc derivatives. The resulting glycopeptides were used to evaluate the substrate specificity of hOGA toward the sugar moiety. This study will provide insights into the exploration of probes for O-GlcNAc modification, as well as a better understanding of the roles of O-GlcNAc in cellular physiology
(E)-2,3-Bis(4-methoxyphenyl)acrylic acid
In the title molecule, C17H16O4, the angle between the aromatic ring planes is 69.1 (6)°. The crystal structure is stabilized by intermolecular O—H⋯O hydrogen bonds; molecules related by a centre of symmetry are linked to form inversion dimers
Three-Dimensional Organoid System Transplantation Technologies in Future Treatment of Central Nervous System Diseases
In recent years, scientists have made great achievements in understanding the development of human brain and elucidating critical elements of stepwise spatiotemporal control strategies in neural stem cell specification lineage, which facilitates successful induction of neural organoid in vitro including the cerebral cortex, cerebellar, neural tube, hippocampus cortex, pituitary, and optic cup. Besides, emerging researches on neural organogenesis promote the application of 3D organoid system transplantation in treating central nervous system (CNS) diseases. Present review will categorize current researches on organogenesis into three approaches: (a) stepwise, direct organization of region-specific or population-enriched neural organoid; (b) assemble and direct distinct organ-specific progenitor cells or stem cells to form specific morphogenesis organoid; and (c) assemble embryoid bodies for induction of multilayer organoid. However, the majority of these researches focus on elucidating cellular and molecular mechanisms involving in brain organogenesis or disease development and only a few of them conducted for treating diseases. In this work, we will compare three approaches and also analyze their possible indications for diseases in future treatment on the basis of their distinct characteristics
Efficacy of sorafenib on metastatic renal cell carcinoma in Asian patients: Results from a multicenter study
<p>Abstract</p> <p>Background</p> <p>The effects of sorafenib in the treatment of advanced renal cell carcinoma (RCC) have been confirmed in an international collaborative phase III trial. This study aims to confirm similar efficacy and treatment-induced toxicities of sorafenib in the treatment of metastatic RCC in ethnic Chinese patients.</p> <p>Methods</p> <p>Ninety-eight consecutive and non-selected patients with pathologically confirmed metastatic RCC were treated according to an institutional treatment protocol. All patients were treated with 400 mg of sorafenib orally twice daily on a continuous basis until disease progression or intolerance to treatment occurred. Dose reduction to 400 mg once daily was required if grade 3 or 4 toxicities occurred. All patients except for 7 received nephrectomy in the course of their disease. All patients were assessed for tumor response, progression-free survival (PFS), overall survival (OS), and treatment-induced toxicities.</p> <p>Results</p> <p>The median follow-up time was 76 weeks (range 2–296 weeks) for the entire group of patients. Radiologically confirmed complete response (CR), partial response (PR), stable disease (SD) of more than 4 months, and disease progression as best objective responses were observed in 1 (1%), 23 (23.5%), 62 (63.3%), and 12 (12.2%) patients, respectively. The tumor control rate (CR+PR+SD of >4 months) was 87.8%. The 1-year estimated PFS and OS were 58.4% and 64.6%, respectively. The median progression-free survival (PFS) time was 60 weeks (95% CI 41–79); and the median overall survival (OS) time was not reached with a follow-up of 76 weeks. Reduction of sorafenib dose was required in 26 patients who developed grade 3 or 4 treatment-cause adverse-effects. An additional 9 patients discontinued sorafenib treatment due to severe adverse-effects. No grade 5 toxicity occurred.</p> <p>Multivariate analysis revealed that independent predictive factors for tumor response to sorafenib treatment included ECOG status, presence of lymph node metastasis, and nephrectomy prior to the development of metastasis.</p> <p>Conclusion</p> <p>Sorafenib produced an 87.8% disease control rate for metastatic renal cell carcinoma in Chinese patients, with acceptable rates of toxicity. The medication dosed at 400 mg twice daily is both efficacious and safe in the treatment of metastatic renal cell carcinoma in Chinese patients.</p
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