Vacuum-isolation vessel and method for measurement of thermal noise in microphones

The vacuum isolation vessel and method in accordance with the present invention are used to accurately measure thermal noise in microphones. The apparatus and method could be used in a microphone calibration facility or any facility used for testing microphones. Thermal noise is measured to determine the minimum detectable sound pressure by the microphone. Conventional isolation apparatus and methods have been unable to provide an acoustically quiet and substantially vibration free environment for accurately measuring thermal noise. In the present invention, an isolation vessel assembly comprises a vacuum sealed outer vessel, a vacuum sealed inner vessel, and an interior suspension assembly coupled between the outer and inner vessels for suspending the inner vessel within the outer vessel. A noise measurement system records thermal noise data from the isolation vessel assembly. A vacuum system creates a vacuum between an internal surface of the outer vessel and an external surface of the inner vessel. The present invention thus provides an acoustically quiet environment due to the vacuum created between the inner and outer vessels and a substantially vibration free environment due to the suspension assembly suspending the inner vessel within the outer vessel. The thermal noise in the microphone, effectively isolated according to the invention, can be accurately measured

Support of the eight-foot high temperature tunnel modification project

In order to meet the need for propulsion testing in the high supersonic range from Mach 4 to Mach 7, NASA has undertaken the modification of the Langley Eight Foot High Temperature Tunnel to add alternate Mach number capability and oxygen enrichment to allow the testing of operating engines at these Mach numbers and at true temperature tunnel. The transfer of liquid oxygen (LOX) from a storage vessel to a rocket engine generally requires the use of a pressurizing gas at high pressures. Although nitrogen is preferred, unfortunately, when gaseous nitrogen (GN2) is used as the pressurant to transfer liquid oxygen from a storage tank to the tunnel combustor, it contaminates the liquid oxygen and effects a loss of performance in the engine. The contamination of the LOX by the pressurizing GN2 is described, which may prove to be an important operational constraint. It is desirable to have reliable data concerning the penetration of GN2 into LOX during pressurization and the subsequent of self cleaning after blowdown

PURIFICATION OF PHOSPHOGYPSUM FOR USE AS CEMENT RETARDER BY SULPHURIC ACID TREATMENT

Phosphogypsum is a by-product of the wet phosphoric acid production. In this study, chemical compositions of phosphogypsum waste (PG) in Hai Phong diammonium phosphate plant (DAP1) and Lao Cai diammonium phosphate plant (DAP2) in Vietnam were surveyed for the purpose of gypsum recovery by P2O5, F removal to meet TCVN11833 for use treated gypsum as cement retarder. Studies of impurities P2O5, F, TOC removal by sulfuric acid 10 % at 28 0C was presented. The results found that the combination of a low concentration of sulfuric acid treatment, washing, lime neutralizing, and thermal treatment was successful in Phoshogypsum treatment for use as cement retarder. The cement test proved that treated PG could partially replace natural gypsum as a retarder.Keywords:  phosphogypsum treatment, phosphorus pentoxide removal, calcium sulfate transition phase, cement retarder.

The positive feedback loop between Nrf2 and phosphogluconate dehydrogenase stimulates proliferation and clonogenicity of human hepatoma cells

© 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.Recent studies report that nuclear factor-erythroid-2-related factor 2 (Nrf2) facilitates tumor progression through metabolic reprogramming in cancer cells. However, the molecular mechanism underlying the oncogenic functions of Nrf2 is not yet well understood. Some of the pentose phosphate pathway (PPP) enzymes are considered to play a role in the cancer progression. The present study was intended to explore the potential role of phosphogluconate dehydrogenase (PGD), one of the PPP enzymes, in the proliferation and migration of human hepatoma HepG2 cells. Genetic ablation of Nrf2 attenuated the expression of PGD at both transcriptional and translational levels. Notably, Nrf2 regulates the transcription of PGD through direct binding to the antioxidant response element in its promoter region. Nrf2 overexpression in HepG2 cells led to increased proliferation, survival, and migration, and these events were suppressed by silencing PGD. Interestingly, knockdown of the gene encoding this enzyme not only attenuated the proliferation and clonogenicity of HepG2 cells but also downregulated the expression of Nrf2. Thus, there seems to exist a positive feedback loop between Nrf2 and PGD which is exploited by hepatoma cells for their proliferation and survival. Treatment of HepG2 cells with ribulose-5-phosphate, a catalytic product of PGD, gave rise to a concentration-dependent upregulation of Nrf2. Collectively, the current study shows that Nrf2 promotes hepatoma cell growth and progression, partly through induction of PGD transcription.

Effect of Plumbagin on growth inhibition and apoptosis of imatinib-resistant chronic myeloid leukemia

Development of a new inhibitor of BCR-ABL tyrosine kinase is necessary for the treatment of chronic myeloid leukemia (CML) because of increasing resistance and tolerance to Imatinid efforts. Herein, we reported Plumbagin can significantly inhibit the growth of CML. The results revealed that Plumbagin inhitbited TCCY and TCCY/T315I cells with IC50 values 3 μM and 2.1 μM, respectively. Plumbagin also showed anti-proliferative effects on both the wide type Ba/F3 and the BCR-ABL-transfected Ba/F3 cells with a range of IC50 from 3.2 to 3.8 μM. In addition, Plumbagin induced the apoptosis of CML cells. That would provide a new and potential drug as a chemotherapy medication in the treatment of Imatinid -resistant CML

Antibacterial activity of crude methanolic and fractionated extracts of Aaptos suberitoides

In this research, we at the first time assessed antibacterial effects of methanolic crude and fractionated extracts from the marine sponge, Aaptos suberitoides against three bacterial strains including E. coli., S. aureus, B. cereus. The anti-bacterial assays were carried out by the disc diffusion method to test the anti-bacterial activity of different concentrations of methanolic crude of A. suberitoides against the indicator bacterial pathogens. The results indicated that extracts of A. suberitoides exhibited anti-microbial activity against all tested bacterial strains in concentrationdependent manner. Moreover, we showed that the majority of the active compound was in the polar fractions

Cross-cultural adaptation and psychometric validation of the Vietnamese version of the evidence-based practice competency questionnaire for registered nurses (EBP-COQ Prof©)

Background & Aim: Establishing strategies to enhance evidence-based practice (EBP) requires a reliable instrument for assessing EBP competency. This study focused on translating and validating the Evidence-Based Practice Competency Questionnaire for Registered Nurses (EBP-COQ Prof©) in the Vietnamese context. Methods & Materials: Through a methodological approach, this study performed cross-cultural adaptation and psychometric validation. The study involved 372 nurses selected through convenience sampling. Content validity was established using the Content Validity Index for Items (I-CVI) and the Content Validity Index for Scales (S-CVI). Construct validity was assessed via exploratory (EFA) and confirmatory factor analysis (CFA). Reliability was determined using Cronbach's alpha and the intra-class correlation coefficient (ICC). Criterion validity was examined by comparing EBP-COQ Prof© competency between nurses with and without prior EBP education. Results: The Vietnamese version of EBP-COQ Prof© maintained consistency with the original version following cross-cultural adaptation. Content validity was confirmed with I-CVI> 0.78 and S-CVI/AVE= 0.97. EFA and CFA revealed consistent components with the original version: attitude (8 items), knowledge (11 items), skills (6 items), and utilization (10 items). Cronbach's alpha values were high: attitudes (0.965), knowledge (0.962), skills (0.909), and utilization (0.926). ICC values were also significant: attitudes (0.754), knowledge (0.895), skills (0.823), and utilization (0.966). Nurses with prior EBP education demonstrated higher EBP-COQ Prof© competency. Conclusion: The translated and validated EBP-COQ Prof© provides a robust tool for assessing EBP competency among Vietnamese nurses. Its reliability, validity, and sensitivity to educational effects underscore its potential for promoting EBP in nursing

An expression signature of the angiogenic response in gastrointestinal neuroendocrine tumours: correlation with tumour phenotype and survival outcomes.

BACKGROUND: Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are heterogeneous with respect to biological behaviour and prognosis. As angiogenesis is a renowned pathogenic hallmark as well as a therapeutic target, we aimed to investigate the prognostic and clinico-pathological role of tissue markers of hypoxia and angiogenesis in GEP-NETs. METHODS: Tissue microarray (TMA) blocks were constructed with 86 tumours diagnosed from 1988 to 2010. Tissue microarray sections were immunostained for hypoxia inducible factor 1α (Hif-1α), vascular endothelial growth factor-A (VEGF-A), carbonic anhydrase IX (Ca-IX) and somatostatin receptors (SSTR) 1–5, Ki-67 and CD31. Biomarker expression was correlated with clinico-pathological variables and tested for survival prediction using Kaplan–Meier and Cox regression methods. RESULTS: Eighty-six consecutive cases were included: 51% male, median age 51 (range 16–82), 68% presenting with a pancreatic primary, 95% well differentiated, 51% metastatic. Higher grading (P=0.03), advanced stage (P<0.001), high Hif-1α and low SSTR-2 expression (P=0.03) predicted for shorter overall survival (OS) on univariate analyses. Stage, SSTR-2 and Hif-1α expression were confirmed as multivariate predictors of OS. Median OS for patients with SSTR-2+/Hif-1α-tumours was not reached after median follow up of 8.8 years, whereas SSTR-2-/Hif-1α+ GEP-NETs had a median survival of only 4.2 years (P=0.006). CONCLUSION: We have identified a coherent expression signature by immunohistochemistry that can be used for patient stratification and to optimise treatment decisions in GEP-NETs independently from stage and grading. Tumours with preserved SSTR-2 and low Hif-1α expression have an indolent phenotype and may be offered less aggressive management and less stringent follow up

Natural and recombinant equine chorionic gonadotropins past and future in animal reproductive technology

Equine Chorionic Gonadotropin (eCG) previously named Pregnant Mare Serum Gonadotropin (PMSG) has been widely used since the 40s in animal reproduction control. It is extracted from the blood of pregnant mares between days 40 and 120 of gestation. Animal welfare organizations have voiced concerns against mares bleeding conditions. There is currently no effective substitute for the natural PMSG. In this review, we summarize the basic knowledge of the structure and biology of eCG, and the research on recombinant eCG production in the past five years

An international comparative study of end-of-life vehicle (ELV) recycling systems

End-of-life vehicles (ELV) have become a global concern as automobiles have become popular worldwide. An international workshop was held to gather data and to discuss 3R policies and ELV recycling systems, their background and present situation, outcomes of related policies and programs, the framework of recycling and waste management, and case studies on related topics in several countries and regions, as well as the essential points of the comparison. Legislative ELV recycling systems are established in the EU, Japan, Korea, and China, while in the US, ELV recycling is managed under existing laws on environmental protection. Since automobile shredding residue (ASR) has a high calorific value and ash content, and includes heavy metals as well as a mass of unclassified fine particles, recycling ASR is considered highly difficult. Countries with a legislative ELV system commonly set a target for recovery rates, with many aiming for more than 95 % recovery. In order to reach this target, higher efficiency in ASR recovery is needed, in addition to material recycling of collectable components and metals. Environmentally friendly design was considered necessary at the planning and manufacturing stages, and the development of recycling systems and techniques in line with these changes are required for sound ELV management