194 research outputs found

    MULTIPLEXED CHEMICAL SENSING AND THIN FILM METROLOGY IN PROGRAMMABLE CVD PROCESS.

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    Mass spectrometry (mass spec) has proven valuable in understanding and controlling chemical processes used in semiconductor fabrication. Given the complexity of spatial distributions of fluid flow, thermal, and chemical parameters in such processes, multi-point chemical sampling would be beneficial. This dissertation discusses the design and development a multiplexed mass spec gas sampling system for real-time, in situ measurement of gas species concentrations in a spatially programmable chemical vapor deposition (SP-CVD) reactor prototype, where such chemical sensing is essential to achieve the benefits of a new paradigm for reactor design. The spatially programmable reactor, in which across-wafer distributions of reactant are programmable, enables (1) uniformity at any desired process design point, or (2) intentional nonuniformity to accelerate process optimization through combinatorial methods. The application of multiplexed mass spec sensing is well suited to our SP-CVD design, which is unique in effectively segmenting the showerhead gas flows by using exhaust gas pumping through the showerhead for each segment. In turn, mass spec sampling signals for each segment are multiplexed to obtain real-time signatures of reactor spatial behavior. In this dissertation, we have reported the results using inert gases to study the spatial distributions of species, validate SP-CVD reactor models, and lead to an understanding of fundamental phenomena associated with the reactor design. This novel multiplexed mass spec sensing system has been employed to monitor the process among three segments in real time. Deliberate non uniform W SP-CVD was performed using H2 reduction of WF6. A process based metrology, which reflects the relationship between the process recipe and film thickness was established. From the process based metrology, a recipe for uniform film deposition was determined and the re-programmability of the SP-CVD system was proven. Meanwhile, a mass spec sensor based film thickness metrology, which reflects the relationship between the normalized mass spec signal and film thickness, was built. Mass spec sensor based thickness metrology with precision of 2~4% was obtained, approaching the desired range of thickness control precision. The scientific contributions from this work are summarized as two points: (1) spatially resolved in situ sensing metrologies have been developed for real-time advanced process control; and (2) the results of this sensing methodology not only demonstrates real-time spatially-distributed end point control, but also makes it possible to guide rapid reprogramming of process recipes intended to achieve simultaneous high material quality and uniformity, or to serve as a valuable asset to potential combinatorial experimental capabilities of the SP-CVD reactor

    1D/3D coupling analysis of engine cooling system

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    In this paper, the FLUENT and KULI soft wares were used to analyze the cooling performance on the radiating module of the cooling system for a heavy vehicle by 1D/3D coupling simulation. According to the analysis, the cooling performance of the existing engine cooling system for heavy vehicles is declined by the gap between the intercooler and radiator in the cooling system. Moreover, the structure of an integrated cooling system was proposed. The wind tunnel experiment model was built in the FLUENT software to analyze the original cooling system and the integrated cooling system by three-dimensional simulation. Then the obtained velocity matrix from 3D simulation was imported into the KULI software to compare the cooling performances of the original system and the integrated system. It was found that the cooling performance of the integrated cooling system is superior to that of the original cooling system

    Vectorial structure of a hard-edged-diffracted four-petal Gaussian beam in the far field

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    Based on the vector angular spectrum method and the stationary phase method and the fact that a circular aperture function can be expanded into a finite sum of complex Gaussian functions, the analytical vectorial structure of a four-petal Gaussian beam (FPGB) diffracted by a circular aperture is derived in the far field. The energy flux distributions and the diffraction effect introduced by the aperture are studied and illustrated graphically. Moreover, the influence of the f-parameter and the truncation parameter on the nonparaxiality is demonstrated in detail. In addition, the analytical formulas obtained in this paper can degenerate into un-apertured case when the truncation parameter tends to infinity. This work is beneficial to strengthen the understanding of vectorial properties of the FPGB diffracted by a circular aperture

    CXCL13/CXCR5 Axis Predicts Poor Prognosis and Promotes Progression Through PI3K/AKT/mTOR Pathway in Clear Cell Renal Cell Carcinoma

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    The chemokine ligands and their receptors play critical roles in cancer progression and patients outcomes. We found that CXCL13 was significantly upregulated in ccRCC tissues compared with normal tissues in both The Cancer Genome Atlas (TCGA) cohort and a validated cohort of 90 pairs ccRCC tissues. Statistical analysis showed that high CXCL13 expression related to advanced disease stage and poor prognosis in ccRCC. We also revealed that serum CXCL13 levels in ccRCC patients (n = 50) were significantly higher than in healthy controls (n = 40). Receiver operating characteristic (ROC) curve revealed that tissue and serum CXCL13 expression might be a diagnostic biomarker for ccRCC with an area under curve (AUC) of 0.809 and 0.704, respectively. CXCL13 was significantly associated with its receptor, CXCR5, in ccRCC tissues, and ccRCC patients in high CXCL13 high CXCR5 expression group have a worst prognosis. Functional and mechanistic study revealed that CXCL13 promoted the proliferation and migration of ccRCC cells by binding to CXCR5 and activated PI3K/AKT/mTOR signaling pathway. These results suggested that CXCL13/CXCR5 axis played a significant role in ccRCC and might be a therapeutic target and prognostic biomarker

    A NEW APPROACH TO SPATIALLY CONTROLLABLE CVD

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    This paper describes the continuing design evolution of a new approach to spatially controllable chemical vapor deposition for electronic materials manufacturing. Based on the success of a previous prototype reactor, we describe construction of a newer version of the prototype reactor system to assess its performance and identify its key operational characteristics. This new design includes a fully automated feed gas control system, allowing the reprogramming of reactor operation without hardware modifications and a time-shared gas sampling mass spectrometer for spatially resolved across-wafer gas composition analysis

    Review of microbiota gut brain axis and innate immunity in inflammatory and infective diseases

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    The microbiota gut brain (MGB) axis has been shown to play a significant role in the regulation of inflammatory and infective diseases. Exploring the structure and communication mode of MGB axis is crucial for understanding its role in diseases, and studying the signaling pathways and regulatory methods of MGB axis regulation in diseases is also of profound significance for future clinical research. This article reviews the composition, communication mechanism of MGB axis and its role in inflammatory and infective diseases, including Parkinsonā€™s disease (PD), Alzheimerā€™s disease (AD), multiple sclerosis (MS), autism spectrum disorder (ASD), depression, psoriasis, irritable bowel syndrome (IBS), and inflammatory bowel diseases (IBD). In addition, our investigation delved into the regulatory functions of the inflammasome, IFN-I, NF-ĪŗB, and PARK7/DJ-1 innate immune signaling pathway in the context of inflammatory and infective diseases. Ultimately, we discussed the efficacy of various interventions, including fecal microbiota transplantation (FMT), antibiotics, probiotics, prebiotics, synbiotics, and postbiotics, in the management of inflammatory and infective diseases. Understanding the role and mechanism of the MGB axis might make positive effects in the treatment of inflammatory and infective diseases

    Non-antibiotic strategies for the prevention of infectious complications following prostate biopsy : A Systematic Review and Meta-analysis

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    Acknowledgments Emma Smith from the EAU Guidelines Office assisted with the systematic review, and Robert Pickard (deceased), Newcastle upon Tyne, United Kingdom, initiated this review.Peer reviewedPostprin

    Long Non-Coding RNA LUCAT1 Promotes Proliferation and Invasion in Clear Cell Renal Cell Carcinoma Through AKT/GSK-3Ī² Signaling Pathway

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    Background/Aims: Long non-coding RNAs (lncRNAs) have emerged as new regulators and biomarkers in several cancers. However, few lncRNAs have been well characterized in clear cell renal cell carcinoma (ccRCC). Methods: We investigated the lncRNA expression profile by microarray analysis in 5 corresponding ccRCC tissues and adjacent normal tissues. Lung cancerā€“associated transcript 1 (LUCAT1) expression was examined in 90 paired ccRCC tissues by real-time PCR and validated by The Cancer Genome Atlas (TCGA) database. Kaplan-Meier analysis was used to examine the prognostic value of LUCAT1 and CXCL2 in ccRCC patients. Loss and gain of function were performed to explore the effect of LUCAT1 on proliferation and invasion in ccRCC cells. Western blotting was performed to evaluate the underlying mechanisms of LUCAT1 in ccRCC progression. Chemokine stimulation assay was performed to investigate possible mechanisms controlling LUCAT1 expression in ccRCC cells. Enzyme-linked immunosorbent assays were performed to determine serum CXCL2 in ccRCC patients and healthy volunteers. Receiver operating characteristic curve analysis was performed to examine the clinical diagnostic value of serum CXCL2 in ccRCC. Results: We found that LUCAT1 was significantly upregulated in both clinical ccRCC tissues (n = 90) and TCGA ccRCC tissues (n = 448) compared with normal tissues. Statistical analysis revealed that the LUCAT1 expression level positively correlated with tumor T stage (P < 0.01), M stage (P < 0.01), and TNM stage (P < 0.01). Overall survival and disease-free survival time were significantly shorter in the high-LUCAT1-expression group than in the low-LUCAT1-expression group (log-rank P < 0.01). LUCAT1 knockdown inhibited ccRCC cell proliferation and colony formation, induced cell cycle arrest at G1 phase, and inhibited cell migration and invasion. Overexpression of LUCAT1 promoted proliferation, migration, and invasion of ccRCC cells. Mechanistic investigations showed that LUCAT1 induced cell cycle G1 arrest by regulating the expression of cyclin D1, cyclin-dependent kinase 4, and phosphorylated retinoblastoma transcriptional corepressor 1. Moreover, LUCAT1 promoted proliferation and invasion in ccRCC cells partly through inducing the phosphorylation of AKT and suppressing the phosphorylation of GSK-3Ī². We also revealed that chemokine CXCL2, upregulated in ccRCC, induced LUCAT1 expression and might be a diagnostic and prognostic biomarker in ccRCC. Conclusions: LUCAT1 was upregulated in ccRCC tissues and renal cancer cell lines, and significantly correlated with malignant stage and poor prognosis in ccRCC. LUCAT1 promoted proliferation and invasion in ccRCC cells through the AKT/GSK-3Ī² signaling pathway. We also revealed that LUCAT1 overexpression was induced by chemokine CXCL2. These findings indicate that the CXCL2/LUCAT1/AKT/GSK-3Ī² axis is a potential therapeutic target and molecular biomarker for ccRCC
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