Preconditioned conjugate-gradient methods for low-speed flow calculations

An investigation is conducted into the viability of using a generalized Conjugate Gradient-like method as an iterative solver to obtain steady-state solutions of very low-speed fluid flow problems. Low-speed flow at Mach 0.1 over a backward-facing step is chosen as a representative test problem. The unsteady form of the two dimensional, compressible Navier-Stokes equations is integrated in time using discrete time-steps. The Navier-Stokes equations are cast in an implicit, upwind finite-volume, flux split formulation. The new iterative solver is used to solve a linear system of equations at each step of the time-integration. Preconditioning techniques are used with the new solver to enhance the stability and convergence rate of the solver and are found to be critical to the overall success of the solver. A study of various preconditioners reveals that a preconditioner based on the Lower-Upper Successive Symmetric Over-Relaxation iterative scheme is more efficient than a preconditioner based on Incomplete L-U factorizations of the iteration matrix. The performance of the new preconditioned solver is compared with a conventional Line Gauss-Seidel Relaxation (LGSR) solver. Overall speed-up factors of 28 (in terms of global time-steps required to converge to a steady-state solution) and 20 (in terms of total CPU time on one processor of a CRAY-YMP) are found in favor of the new preconditioned solver, when compared with the LGSR solver

Two- and three-dimensional viscous computations of a hypersonic inlet flow

The three-dimensional parabolized Navier-Stokes code has been used to investigate the flow through a Mach 7.4 inlet. A two-dimensional parametric study of grid resolution, turbulence modeling and effect of gamma has been done and compared with experimental results. The results show that mesh resolution of the shock waves, real gas effects and turbulence length scaling are very important to get accurate results for hypersonic inlet flows. In addition a three-dimensional calculation of the Mach 7.4 inlet has been done on a straight sideplate configuration. The results show that the glancing shock/boundary layer interaction phenomena causes significant three-dimensional flow in the inlet

CUCHILD: A Large-Scale Cantonese Corpus of Child Speech for Phonology and Articulation Assessment

This paper describes the design and development of CUCHILD, a large-scale Cantonese corpus of child speech. The corpus contains spoken words collected from 1,986 child speakers aged from 3 to 6 years old. The speech materials include 130 words of 1 to 4 syllables in length. The speakers cover both typically developing (TD) children and children with speech disorder. The intended use of the corpus is to support scientific and clinical research, as well as technology development related to child speech assessment. The design of the corpus, including selection of words, participants recruitment, data acquisition process, and data pre-processing are described in detail. The results of acoustical analysis are presented to illustrate the properties of child speech. Potential applications of the corpus in automatic speech recognition, phonological error detection and speaker diarization are also discussed.Comment: Accepted to INTERSPEECH 2020, Shanghai, Chin

Aberrant Transferrin and Ferritin Upregulation Elicits Iron Accumulation and Oxidative Inflammaging Causing Ferroptosis and Undermines Estradiol Biosynthesis in Aging Rat Ovaries by Upregulating NF-Κb-Activated Inducible Nitric Oxide Synthase: First Demonstration of an Intricate Mechanism

We report herein a novel mechanism, unraveled by proteomics and validated by in vitro and in vivo studies, of the aberrant aging-associated upregulation of ovarian transferrin and ferritin in rat ovaries. The ovarian mass and serum estradiol titer plummeted while the ovarian labile ferrous iron and total iron levels escalated with age in rats. Oxidative stress markers, such as nitrite/nitrate, 3-nitrotyrosine, and 4-hydroxy-2-nonenal, accumulated in the aging ovaries due to an aberrant upregulation of the ovarian transferrin, ferritin light/heavy chains, and iron regulatory protein 2(IRP2)-mediated transferrin receptor 1 (TfR1). Ferritin inhibited estradiol biosynthesis in ovarian granulosa cells in vitro via the upregulation of a nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and p65/p50-induced oxidative and inflammatory factor inducible nitric oxide synthase (iNOS). An in vivo study demonstrated how the age-associated activation of NF-κB induced the upregulation of iNOS and the tumor necrosis factor α (TNFα). The downregulation of the keap1-mediated nuclear factor erythroid 2-related factor 2 (Nrf2), that induced a decrease in glutathione peroxidase 4 (GPX4), was observed. The aberrant transferrin and ferritin upregulation triggered an iron accumulation via the upregulation of an IRP2-induced TfR1. This culminates in NF-κB-iNOS-mediated ovarian oxi-inflamm-aging and serum estradiol decrement in naturally aging rats. The iron accumulation and the effect on ferroptosis-related proteins including the GPX4, TfR1, Nrf2, Keap1, and ferritin heavy chain, as in testicular ferroptosis, indicated the triggering of ferroptosis. In young rats, an intraovarian injection of an adenovirus, which expressed iron regulatory proteins, upregulated the ovarian NF-κB/iNOS and downregulated the GPX4. These novel findings have contributed to a prompt translational research on the ovarian aging-associated iron metabolism and aging-associated ovarian diseases

Dissecting the effects of METTL3 on alternative splicing in prostate cancer

Although the role of METTL3 has been extensively studied in many cancers, its role in isoform switching in prostate cancer (PCa) has been poorly explored. To investigate its role, we applied standard RNA-sequencing and long-read direct RNA-sequencing from Oxford Nanopore to examine how METTL3 affects alternative splicing (AS) in two PCa cell lines. By dissecting genome-wide METTL3-regulated AS events, we noted that two PCa cell lines (representing two different PCa subtypes, androgen-sensitive or resistant) behave differently in exon skipping and intron retention events following METTL3 depletion, suggesting AS heterogeneity in PCa. Moreover, we revealed that METTL3-regulated AS is dependent on N6-methyladenosine (m6A) and distinct splicing factors. Analysis of the AS landscape also revealed cell type specific AS signatures for some genes (e.g., MKNK2) involved in key functions in PCa tumorigenesis. Finally, we also validated the clinical relevance of MKNK2 AS events in PCa patients and pointed to the possible regulatory mechanism related to m6A in the exon14a/b region and SRSF1. Overall, we characterize the role of METTL3 in regulating PCa-associated AS programs, expand the role of METTL3 in tumorigenesis, and suggest that MKNK2 AS events may serve as a new potential prognostic biomarker

A Preliminary Analysis of Combined Liver Resection With New Chemotherapy for Synchronous and Metachronous Colorectal Liver Metastasis

ObjectiveTo compare the survival between patients with synchronous and metachronous colorectal liver metastases after hepatectomy with new generation of perioperative chemotherapy.MethodsFrom October 2002 to January 2008, patients receiving hepatectomy for synchronous or metachronous colorectal liver metastasis were studied retrospectively.ResultsFifty-five patients (synchronous group = 35, metachronous group = 20) underwent hepatectomy for colorectal liver metastases. Besides younger age with male predominance, patients in the synchronous group had more tumour multinodularity and bilobe liver involvement. They had received less hepatic curative hepatectomy (81.1% vs. 100%) with a higher rate of peri-operative chemotherapy (91.4% vs. 50%) and postoperative morbidity (25.7% vs. 0%). However both groups had no statistical significant difference in median overall survival (OS) and disease free survival (DFS). Inferior OS and DFS were observed in the synchronous group for patients who had no peri-operative chemotherapy or those showing poor response to chemotherapy. The most favourable OS is observed in both groups after performing globally curative hepatectomy.ConclusionSynchronous colorectal liver metastasis is not a poor prognostic factor for survival when compared with the metachronous metastasis. Globally curative hepatectomy in combination of new generation of chemotherapy is recommended for the management of resectable colorectal liver metastasis

Incidence, risk factors, and temporal trends of penile cancer:a global population-based study

Objectives: To examine the global disease burden and country-specific trends of penile cancer incidence by age group and investigate its associations with several factors. Materials and Methods: The Global Cancer Observatory database was interrogated for penile cancer incidence. The 10-year cancer incidence rates were collected from the Cancer Incidence in Five Continents Plus. The country-specific data were extracted from the World Health Organization Global Health Observatory and Global Burden of Disease databases for conducting risk factors analysis. The penile cancer incidence was presented using age-standardised rates. Its associations with various factors were examined by linear regression, while the incidence trend was estimated using joinpoint regression and presented as average annual percentage change with 95% confidence intervals in different age groups. Results: There were an estimated 36 068 new cases of penile cancer in 2020. There was a considerable geographical disparity in the disease burden of penile cancer, with South America reporting the highest incidence. Overall, alcohol drinking, human immunodeficiency virus (HIV) infection, and unsafe sex were positively associated with a higher penile cancer incidence, while circumcision was found to be a protective factor. There has been a mixed trend in penile cancer incidence overall, but an increasing trend was found among younger males. Conclusions: There was a global variation in the penile cancer burden associated with prevalence of alcohol drinking, HIV infection, unsafe sex, and circumcision. The increasing penile cancer incidence in the younger population is worrying and calls for early detection and preventive interventions.</p

Incidence, risk factors, and temporal trends of penile cancer:a global population-based study

Objectives: To examine the global disease burden and country-specific trends of penile cancer incidence by age group and investigate its associations with several factors. Materials and Methods: The Global Cancer Observatory database was interrogated for penile cancer incidence. The 10-year cancer incidence rates were collected from the Cancer Incidence in Five Continents Plus. The country-specific data were extracted from the World Health Organization Global Health Observatory and Global Burden of Disease databases for conducting risk factors analysis. The penile cancer incidence was presented using age-standardised rates. Its associations with various factors were examined by linear regression, while the incidence trend was estimated using joinpoint regression and presented as average annual percentage change with 95% confidence intervals in different age groups. Results: There were an estimated 36 068 new cases of penile cancer in 2020. There was a considerable geographical disparity in the disease burden of penile cancer, with South America reporting the highest incidence. Overall, alcohol drinking, human immunodeficiency virus (HIV) infection, and unsafe sex were positively associated with a higher penile cancer incidence, while circumcision was found to be a protective factor. There has been a mixed trend in penile cancer incidence overall, but an increasing trend was found among younger males. Conclusions: There was a global variation in the penile cancer burden associated with prevalence of alcohol drinking, HIV infection, unsafe sex, and circumcision. The increasing penile cancer incidence in the younger population is worrying and calls for early detection and preventive interventions.</p

Carboxyl-terminal truncated HBx regulates a distinct microRNA transcription program in Hepatocellular carcinoma development

Background: The biological pathways and functional properties by which misexpressed microRNAs (miRNAs) contribute to liver carcinogenesis have been intensively investigated. However, little is known about the upstream mechanisms that deregulate miRNA expressions in this process. In hepatocellular carcinoma (HCC), hepatitis B virus (HBV) X protein (HBx), a transcriptional trans-activator, is frequently expressed in truncated form without carboxyl-terminus but its role in miRNA expression and HCC development is unclear. Methods: Human non-tumorigenic hepatocytes were infected with lentivirus-expressing full-length and carboxyl-terminal truncated HBx (Ct-HBx) for cell growth assay and miRNA profiling. Chromatin immunoprecipitation microarray was performed to identify the miRNA promoters directly associated with HBx. Direct transcriptional control was verified by luciferase reporter assay. The differential miRNA expressions were further validated in a cohort of HBV-associated HCC tissues using real-time PCR. Results: Hepatocytes expressing Ct-HBx grew significantly faster than the full-length HBx counterparts. Ct-HBx decreased while full-length HBx increased the expression of a set of miRNAs with growth-suppressive functions. Interestingly, Ct-HBx bound to and inhibited the transcriptional activity of some of these miRNA promoters. Notably, some of the examined repressed-miRNAs (miR-26a, -29c, -146a and -190) were also significantly down-regulated in a subset of HCC tissues with carboxyl-terminal HBx truncation compared to their matching non-tumor tissues, highlighting the clinical relevance of our data. Conclusion: Our results suggest that Ct-HBx directly regulates miRNA transcription and in turn promotes hepatocellular proliferation, thus revealing a viral contribution of miRNA deregulation during hepatocarcinogenesis. © 2011 Yip et al.published_or_final_versio