Energy Analysis of a Novel Ejector-Compressor Cooling Cycle Driven by Electricity and Heat (Waste Heat or Solar Energy)

Low-grade heat is abundantly available as solar thermal energy and as industrial waste heat. Non concentrating solar collectors can provide heat with temperatures 75−100 °C. In this paper, a new system is proposed and analyzed which enhances the electrical coefficient of performance (COP) of vapour compression cycle (VCC) by incorporating low-temperature heat-driven ejectors. This novel system, ejector enhanced vapour compression refrigeration cycle (EEVCRC), significantly increases the electrical COP of the system while utilizing abundantly available low-temperature solar or waste heat (below 100 °C). This system uses two ejectors in an innovative way such that the higher-pressure ejector is used at the downstream of the electrically driven compressor to help reduce the delivery pressure for the electrical compressor. The lower pressure ejector is used to reduce the quality of wet vapour at the entrance of the evaporator. This system has been modelled in Engineering Equation Solver (EES) and its performance is theoretically compared with conventional VCC, enhanced ejector refrigeration system (EERS), and ejection-compression system (ECS). The proposed EEVCRC gives better electrical COP as compared to all the three systems. The parametric study has been conducted and it is found that the COP of the proposed system increases exponentially at lower condensation temperature and higher evaporator temperature. At 50 °C condenser temperature, the electrical COP of EEVCRC is 50% higher than conventional VCC while at 35 °C, the electrical COP of EEVCRC is 90% higher than conventional VCC. For the higher temperature heat source, and hence the higher generator temperatures, the electrical COP of EEVCRC increases linearly while there is no increase in the electrical COP for ECS. The better global COP indicates that a small solar collector will be needed if this system is driven by solar thermal energy. It is found that by using the second ejector at the upstream of the electrical compressor, the electrical COP is increased by 49.2% as compared to a single ejector system

Case study of lean manufacturing application in a die casting manufacturing company

The case study of lean manufacturing aims to study the application of lean manufacturing in a die casting manufacturing company located in Pulau Penang, Malaysia. This case study describes mainly about the important concepts and applications of lean manufacturing which could gradually help the company in increasing the profit by studying and analyzing their current manufacturing process and company culture. Many approaches of lean manufacturing are studied in this project which includes: 5S housekeeping, Kaizen, and Takt Time. Besides, the lean tools mentioned, quality tool such as the House of Quality is being used as an analysis tool to continuously improve the product quality. In short, the existing lean culture in the company is studied and analyzed, with recommendations written at the end of this paper

Over-expression of the mitogen-activated protein kinase (MAPK) kinase (MEK)-MAPK in hepatocellular carcinoma: Its role in tumor progression and apoptosis

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignancies in South East Asia. Although activation of the MEK-MAPK is often associated with cellular growth, the role of MEK-MAPK in growth and survival of hepatocarcinoma cells has not been established. METHODS: Immuno-histochemistry was used to localize phosphorylated MAPK and MEK1/2 in the tissues. 3-(4,5-Dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) assay and ELISA were used to determine cell viability and cell proliferation. Deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay was used to detect apoptotic cells. Western blots analysis was performed to determine the levels of proteins involved in the MEK-MAPK and apoptotic pathways. Transfection study was performed to assess the role of MEK-MAPK pathway in growth and survival of liver cancer cells. RESULTS: We report that phosphorylation of MEK1/2 at Ser217/221 was detected by immuno-histochemistry in 100% (46 of 46) of HCCs examined. A positive signal was localized in the nuclei of hepatocarcinoma cells but not in dysplastic hepatocytes or stromal cells. Over-expression and phosphorylation of MAPK was also detected in 91% (42 of 46) and 69% (32 of 46) of HCCs examined, respectively. The percentage of cells showing positively for phosphorylated MEK1/2 increased with advancing tumor stage. In vitro, treatment of human HepG2 and Hep3B cells with MEK1/2 specific inhibitors U0126 and PD98059 led to growth inhibition and apoptosis. U0126 induced the release of cytochrome c and increased the cleavage of caspase-3, caspase-7, and poly ADP-ribose polymerase (PARP). Inhibition of phosphatidylinositol 3-kinase (PI-3K), c-Jun N-terminal kinase (JNK) and p38 kinase activities caused only a mild apoptosis in HepG2 and Hep3B cells. Activated MEK1-transfected cells were more resistant to UO126-induced apoptosis in vitro and formed larger tumors in SCID mice than mock-transfected cells. CONCLUSION: In conclusion, our results demonstrate that MEK-MAPK plays an important role in the growth and survival of liver cancer cells and suggest that blocking MEK-MAPK activity may represent an alternative approach for the treatment of liver cancer

Utility of combining PIVKA-II and AFP in the surveillance and monitoring of hepatocellular carcinoma in the Asia-Pacific region

Even though the combined use of ultrasound (US) and alpha-fetoprotein (AFP) is recommended for the surveillance of hepatocellular carcinoma (HCC), the utilization of AFP has its challenges, including accuracy dependent on its cut-off levels, degree of liver necroinflammation, and etiology of liver disease. Though various studies have demonstrated the utility of protein induced by vitamin K absence II (PIVKA-II) in surveillance, treatment monitoring, and predicting recurrence, it is still not recommended as a routine biomarker test. A panel of 17 experts from Asia-Pacific, gathered to discuss and reach a consensus on the clinical usefulness and value of PIVKA-II for the surveillance and treatment monitoring of HCC, based on six predetermined statements. The experts agreed that PIVKA-II was valuable in the detection of HCC in AFP-negative patients, and could potentially benefit detection of early HCC in combination with AFP. PIVKA-II is clinically useful for monitoring curative and intra-arterial locoregional treatments, outcomes, and recurrence, and could potentially predict microvascular invasion risk and facilitate patient selection for liver transplant. However, combining PIVKA-II with US and AFP for HCC surveillance, including small HCC, still requires more evidence, whilst its role in detecting AFP-negative HCC will potentially increase as more patients are treated for hepatitis-related HCC. PIVKA-II in combination with AFP and US has a clinical role in the Asia-Pacific region for surveillance. However, implementation of PIVKA-II in the region will have some challenges, such as requiring standardization of cut-off values, its cost-effectiveness and improving awareness among healthcare providers

A Strategic Initiative for Successful Reverse Logistics Management in Retail Industry

This study aims to identify critical factors for developing a successful reverse logistics strategic framework that could guide the managers for improving customer satisfaction and managing retail returns. Qualitative interviews were performed with logistics manager in retail industry to develop successful reverse logistics strategic framework with critical factors. A problem-driven content analysis methodology was also conducted reviewing previous studies published from 2008 through 2015 to determine the key factors that affect reverse logistics decisions of managers towards successful reverse logistics management. This study provided new insight on reverse logistics as an important strategic initiative for the retailers to gain customer satisfaction, competitive advantage and cost effectiveness. A reverse logistics framework that is developed in this article will be able to add value to supply chain and logistics studies. Reverse flow driven by motivation is an important implication for managers to manage logistics activities. Managers must emphasize on potential corporate benefits to reduce costs and add customer value

Youth olympic village Co-Space

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Second-order surface-plasmon assisted responsivity enhancement in germanium nano-photodetectors with bull's eye antennas

The enhancement of photo-response in nanometer-scale germanium photodetectors through bull's eye antennas capable of supporting 2nd-order Bloch surface plasmon modes is demonstrated in theory and experiment. A detailed numerical investigation reveals that the presence of surface wave and its constructive interference with the directly incident light are incorporated into the main mechanisms for enhancing transmission through the central nanoaperture. With a grating period of 1500 nm, the area-normalized responsivity can be enhanced up to 3.8 times at 2 V bias for a 780 nm laser. It provides an easier fabrication path for ultra-short wavelength operations especially in devices using optically denser materials.This work was supported by the Australian Research Council Discovery Early Career Researcher Award (DE130101700), the National Natural Science Foundation of China (Nos. 11104130, 61274058, 61322403, 60825401, and 60936004), the Basic Research Program of Jiangsu Province (Nos. BK2011556, BK2011437, and BK20130013), and the State Key Program for Basic Research of China (Nos. 2010CB327504 and 2011CB301900)

The role of tyrosine hydroxylase-dopamine pathway in Parkinson's disease pathogenesis

Background: Parkinson’s disease (PD) is characterized by selective and progressive dopamine (DA) neuron loss in the substantia nigra and other brain regions, with the presence of Lewy body formation. Most PD cases are sporadic, whereas monogenic forms of PD have been linked to multiple genes, including Leucine kinase repeat 2 (LRRK2) and PTEN-induced kinase 1 (PINK1), two protein kinase genes involved in multiple signaling pathways. There is increasing evidence to suggest that endogenous DA and DA-dependent neurodegeneration have a pathophysiologic role in sporadic and familial PD. Methods: We generated patient-derived dopaminergic neurons and human midbrain-like organoids (hMLOs), transgenic (TG) mouse and Drosophila models, expressing both mutant and wild-type (WT) LRRK2 and PINK1. Using these models, we examined the effect of LRRK2 and PINK1 on tyrosine hydroxylase (TH)–DA pathway. Results: We demonstrated that PD-linked LRRK2 mutations were able to modulate TH–DA pathway, resulting in up-regulation of DA early in the disease which subsequently led to neurodegeneration. The LRRK2-induced DA toxicity and degeneration were abrogated by wild-type (WT) PINK1 (but not PINK1 mutations), and early treatment with a clinical-grade drug, α-methyl-L-tyrosine (α-MT), a TH inhibitor, was able to reverse the pathologies in human neurons and TG Drosophila models. We also identified opposing effects between LRRK2 and PINK1 on TH expression, suggesting that functional balance between these two genes may regulate the TH–DA pathway. Conclusions: Our findings highlight the vital role of the TH–DA pathway in PD pathogenesis. LRRK2 and PINK1 have opposing effects on the TH–DA pathway, and its balance affects DA neuron survival. LRRK2 or PINK1 mutations can disrupt this balance, promoting DA neuron demise. Our findings provide support for potential clinical trials using TH–DA pathway inhibitors in early or prodromic PD.Published versionThis study was supported by Singapore National Medical Research Council (NMRC), STaR 0030/2018 and OF PD LCG 000207 to T-EK

Splice‐switch oligonucleotide‐based combinatorial platform prioritizes synthetic lethal targets CHK1 and BRD4 against MYC‐driven hepatocellular carcinoma

Abstract Deregulation of MYC is among the most frequent oncogenic drivers in hepatocellular carcinoma (HCC). Unfortunately, the clinical success of MYC‐targeted therapies is limited. Synthetic lethality offers an alternative therapeutic strategy by leveraging on vulnerabilities in tumors with MYC deregulation. While several synthetic lethal targets of MYC have been identified in HCC, the need to prioritize targets with the greatest therapeutic potential has been unmet. Here, we demonstrate that by pairing splice‐switch oligonucleotide (SSO) technologies with our phenotypic‐analytical hybrid multidrug interrogation platform, quadratic phenotypic optimization platform (QPOP), we can disrupt the functional expression of these targets in specific combinatorial tests to rapidly determine target–target interactions and rank synthetic lethality targets. Our SSO‐QPOP analyses revealed that simultaneous attenuation of CHK1 and BRD4 function is an effective combination specific in MYC‐deregulated HCC, successfully suppressing HCC progression in vitro. Pharmacological inhibitors of CHK1 and BRD4 further demonstrated its translational value by exhibiting synergistic interactions in patient‐derived xenograft organoid models of HCC harboring high levels of MYC deregulation. Collectively, our work demonstrates the capacity of SSO‐QPOP as a target prioritization tool in the drug development pipeline, as well as the therapeutic potential of CHK1 and BRD4 in MYC‐driven HCC