Search

The existing reflector not requiring solar tracking used in solar flat-plate collector is mainly plate-type structure. This kind of structure is simple, but it is not the optimal one. To solve this problem, the new polyline-type and parabolic-type reflectors not requiring solar tracking were proposed for solar flat-plate collectors in this paper. A comparative study of the two types of reflectors and the existing plate-type reflectors under no sun-tracking conditions was carried out by theoretical and experimental methods. The reflected light losses under the off-design conditions were analyzed. The transient and annual operation characteristics were discussed. The results showed that under the design conditions the ranking of boost factor is parabolic-type, polyline-type and plate-type. But the reflection losses under the off-design conditions are just the opposite. Under the same reflective area with the collectors, when the reflection losses are considered, the increases of solar radiation on the collectors are 40.3%, 27.7% and 19.8% for the polyline, parabolic and flat-plate reflectors respectively in the heating season. In the coldest three months, the polyline-type always has the largest solar radiation. This paper is helpful to improve the efficiency and economy of solar space heating in cold areas.

Background Expression of the long non-coding mRNA LINC00152 has been reported to correlate with cancer cell resistance to oxaliplatin (L-OHP). However, little is known regarding the molecular mechanism of LINC00152 in esophageal cancer (EC). Hence, we intended to characterize the role of LINC00152 in EC, with a special focus on epithelial-mesenchymal transition (EMT) and L-OHP resistance. Methods We collected EC tissues and identified EC cell lines with higher L-OHP resistance, and then characterized expression patterns of LINC00152, Zeste Homologue 2 (EZH2), Zinc finger e-box binding homeobox (ZEB1) and EMT-related genes using RT-qPCR and Western blot analysis. Furthermore, their functional significance was identified by gain and loss-of-function experiments. The relationship among LINC00152, EZH2 and ZEB1 was examined using RIP, RNA pull-down and ChIP assays. Additionally, resistance of EC cells to L-OHP was reflected by CCK-8 assay to detect cell viability. Animal experiments were also conducted to detect the effects of the LINC00152/EZH2/ZEB1 on EMT and L-OHP resistance. Results LINC00152, EZH2 and ZEB1 were highly expressed in EC tissues and Kyse−150/TE-1 cells. As revealed by assays in vitro and in vivo, LINC00152 positively regulated ZEB1 expression through interaction with EZH2 to enhance EMT and L-OHP resistance in EC cells. In contrast, silencing of LINC00152 contributed to attenuated EMT and drug resistance of EC cells to L-OHP. Conclusions Our study demonstrates that LINC00152/EZH2/ZEB1 axis can regulate EMT and resistance of EC cells to L-OHP, thus presenting a potential therapeutic target for EC treatment.

This chapter numerically investigates condensation flow and heat transfer characteristics of hydrocarbon refrigerants in a spiral tube of a spiral-wound heat exchanger. First, a numerical model under static and sloshing conditions was established, and numerical results were verified based on experimental data. Then, pressure drop and heat transfer performances of hydrocarbon refrigerants in a spiral tube were discussed at static and sloshing conditions with different parameters. Finally, the effects of different sloshing motions (heave, roll, and pitch) on condensation flow and heat transfer of hydrocarbon refrigerants were evaluated.

Finned-tube evaporators have been widely used in air source heat pumps. Coating a solar selective absorbing coating on the fin surface is proved an effective approach to improve the heat transfer effects of finned-tube evaporators using solar energy. However, currently, most attentions were paid to the performance improvement of heat pump systems assisted by solar energy, scarce of attentions were paid to the heat transfer characteristics of this kind of fin under solar radiation. Therefore, the heat transfer characteristics of this kind of fin under solar radiation were studied using the heat transfer theory. Based on the heat transfer models, the theoretical solution of temperature field was deduced, and its accuracy was validated by numerical simulation. The effects of various factors on the heat transfer characteristics of a plain fin were theoretically analyzed. The results showed that the solar radiation would lessen the convective heat transfer capacity and fin efficiency, and even make part of solar energy to release into the environment. The maximum loss of solar energy accounts for about 12.7% of the total solar energy, and twice the fin height only generates 60% increase of the total heat transfer capacity. In the condition of larger fin height and solar radiation, the smaller convective heat transfer coefficient will produce more total heat transfer capacity. This study is helpful to analyze this kind of heat transfer problem and guide the optimization design of finned-tube evaporators assisted by solar energy.

A numerical model of condensation heat transfer and frictional pressure drop in a circular tube was developed and validated. In order to facilitate the model validation, the physical model was built according to the experiment condition in the existing literature. In the numerical models proposed in this work, the following models were involved: volume of fluid (VOF) multiphase model, Lee’s phase change model and Reynolds Stress turbulence model. The importance of boundary-layer mesh size was analyzed, and the effects of entrainment, turbulent Prandtl number and gas-liquid interface turbulence damping on the simulation results of heat transfer coefficient (HTC) and frictional pressure drop (FPD) were evaluated and modified. The numerical model was validated with Neeraas’s experimental data and Steiner's correlation results at various mass fluxes, vapor qualities, pressures and fluids. The simulation results of void fraction showed good agreement with Steiner's correlation; the HTC and FPD showed good agreement with Neeraas’s experimental data, which indicated the model developed in this work has good universality and accuracy.

Approximately 85% of a single administered dose of 5-fluorouracil (5-FU) will be degraded by dihydropyrimidine dehydrogenase (DYPD). Studies have highlighted a link between the complete or partial loss of DYPD function and clinical responses to 5-FU; however, the underlying molecular basis of DPD deficiency remains poorly understood. Hence, the aim of the present study was to evaluate the prevailing hypothesis which suggests that overexpression of LINC00261 possesses the ability to modulate the methylation-dependent repression of DPYD, ultimately resulting in an elevation of the sensitivity of human esophageal cancer cells to 5-FU. LINC00261 levels were initially quantified, followed by analysis of DYPD methylation within the cancerous tissues collected from 75 patients diagnosed with esophageal cancer undergoing 5-FU-based adjuvant chemotherapy. In an attempt to determine the levels of LINC00261 related to the esophageal cancer cell resistance to 5-FU and to identify the interaction between the levels of LINC00261 and methylation of the DYPD promoter, esophageal cancer cells TE-1 and -5 were prepared, in which LINC00261 and the 5-FU-resistant TE-1 and -5 cells were overexpressed. The levels of LINC00261 were reduced among the cancerous tissues obtained from patients exhibiting resistance to 5-FU. Overexpression of LINC00261 was determined to dramatically inhibit proliferation and resistance to apoptosis among 5-FU-resistant TE-1 and -5 cells, whereas silencing of LINC00261 was determined to enhance proliferation and resistance to apoptosis among the TE-1 and -5 cells. DPYD, a confirmed target of LINC00261, displayed a greater incidence of DNA methylation among patient's sensitive to 5-FU. A key finding revealed that overexpressed LINC00261 could increase the methylation of the DPYD promoter through the recruitment of DNA methyltransferase (DNMT), which, in turn, acts to decrease DPYD activity in 5-FU-resistant TE-1 cells, whereas a reversible change was recorded once the demethylation reagent 5-aza-2'-deoxyctidine was employed to treat the 5-FU-resistant TE-1 cells. Taken together, the results of the study provided evidence emphasizing the distinct antitumor ability of LINC00261 in cases of esophageal cancer, which was manifested by overexpression of LINC00261 detected to increase the sensitivity of human esophageal cancer cells to 5-FU by mediating methylation-dependent repression of DPYD. Our study highlighted the potential of LINC00261 as a novel target capable of improving the chemotherapeutic response and survival of patients with esophageal cancer.-Lin, K., Jiang, H., Zhuang, S.-S., Qin, Y.-S., Qiu, G.-D., She, Y.-Q., Zheng, J.-T., Chen, C., Fang, L., Zhang, S.-Y. Long noncoding RNA LINC00261 induces chemosensitization to 5-fluorouracil by mediating methylation-dependent repression of DPYD in human esophageal cancer.

Background Paclitaxel (PTX) has remarkable anti-tumor activity, but it causes severe toxicities. There is an urgent need to seek an appropriate pharmacokinetic parameter of PTX to improve treatment efficacy and reduce adverse effects. Objective To evaluate the association of pharmacokinetic parameter TC > 0.05 of paclitaxel (PTX) and its therapeutic efficacy and toxicity in patients with solid tumors. Methods A total of 295 patients with ovarian cancer, esophageal cancer, breast cancer, and non-small cell lung cancer (NSCLC), who were admitted to the Tumor Hospital of Shantou University Medical College, China, were recruited for this study. Patients received 3 weeks of PTX chemotherapy. The plasma concentrations of PTX were examined using the MyPaclitaxel™ kit. The patients' PTX TC > 0.05 (the time during which PTX plasma concentration exceed 0.05µmol/L) were calculated based on pharmacokinetic analysis. Results The results showed that: (1) the concentrations of PTX in these 295 patients ranged from 0.0358-0.127 µmol/L; (2) the PTX TC > 0.05 ranged from 14 to 38h with a median time of 27h; (3) among all treatment cycles, there was a statistically significant difference in the PTX TC > 0.05 between CR+PR and SD+PD; (4) with the increasing value of TC > 0.05, level of leukopenia and leukopenic fever increased; (5) high PTX TC > 0.05 led to the occurrence of neutropenia, neutropenic fever, severe anemia, and severe peripheral neurotoxicity. Taken together, our results indicated that the pharmacokinetic parameter PTX TC > 0.05 was an effective measure of treatment efficacy and toxicity in patients with solid tumors. Maintaining PTX TC > 0.05 at 26 to 30h could improve its efficacy and reduce the incidence of leukopenia, neutropenia, anemia, and peripheral neurotoxicity in these patients. Conclusion PTX TC > 0.05 is a key pharmacokinetic parameter of PTX which should be monitored to optimize individual treatment in patients with solid tumors.

Coil-wound heat exchangers (CWHEs) have been widely used in natural gas liquefaction plants nowadays. But few studies on the condensation heat transfer and frictional pressure drop of mixed hydrocarbon refrigerants inside the tubes of CWHEs have been conducted under practical conditions. In this study, numerical simulations were carried out to investigate the condensation flow and heat transfer characteristics of mixed hydrocarbon refrigerants inside the tubes of liquefied natural gas (LNG) CWHEs under practical operating conditions. A combinational numerical method based on computational fluid dynamics (CFD) simulation and modified Silver method was proposed to predict the condensation heat transfer coefficients of mixtures. The numerical results showed good agreement with experimental data and calculation results by the empirical correlation in the literature. The relative errors of void fraction, heat transfer coefficient and frictional pressure drop were predicted within ±5%, ±15% and ±15% respectively. The simulation results indicated that the heat transfer coefficients of mixed refrigerants varied slightly with the increase of vapor quality, but significantly with the increase of mass flux. And the frictional pressure drop increased with the increase of both vapor quality and mass flux. This study is instructive to the design and optimization of CWHEs used for natural gas liquefaction process.

HOX transcript antisense intergenic RNA (HOTAIR) is a relatively well-understood RNA, which plays a central role in the pathogenesis of various tumors. The aim of the present study was to investigate the effect by which HOTAIR acts to influence the biological processes of colorectal cancer (CRC) through p21. Reverse transcription quantitative polymerase chain reaction and Western blot methods were employed to provide verification regarding the changes in HOTAIR, PCNA, Ki67, p21, cyclin E, and CDK2 among the CRC tissues and cells. The correlation between the clinicopathological characteristics of patients and expression of HOTAIR and p21 was subsequently evaluated, followed by an analysis into the effects of HOTAIR on the biological processes of M5 cells. HOTAIR was found to be expressed at high levels, while p21 was determined to be at a low level among both the CRC tissues and the CRC cell lines. The expressions of HOTAIR and p21 were determined to be related to lymph node metastasis, tumor node metastasis, Dukes staging, distant metastases, histological types, and the degree of differentiation. Cells transfected with HOTAIR siRNA displayed inhibited rates of proliferation, invasion, and migration, as well as decreased cyclin E and CDK2, while apoptosis and p21 were increased. The principal findings demonstrated that down-regulation of HOTAIR elicits an inhibitory effect on proliferation, invasion, and migration, while promoting the apoptosis of CRC cells through the up-regulation of p21. We believe that HOTAIR could represent a novel target for the treatment of CRC.

Carbon nanotube–polyaniline brush-like nanostructures have been successfully synthesized through in situ oxidative polymerization of aniline on the surface of carboxylated multi-walled carbon nanotubes. The diameter of the resultant tubular nanobrushes is dependent on the mass ratio of c-MWNTs to aniline. The as-designed carbon nanotube–polyaniline nanobrushes exhibit superior electroactivity not only in acidic, but also in neutral and alkaline environments. The excellent anticorrosion performance has been achieved by incorporation of these nanobrushes into amine cured epoxy modified acrylic resin. It is found that the good barrier property of the nanobrush coating against neutral and alkaline corrosion media penetration and its predominant passivation protection against acidic medium offer anticorrosion protection for steel over a wide pH range. The novel carbon nanotube–polyaniline nanobrushes prepared using this facile route extend the application of polyaniline to a wider range of pH environments and facilitate a more environmentally friendly and economical system than traditional heavy metal coatings and their oxide coatings, in the application of anticorrosion protection of metals.

Esophageal cancer (EC) is one of the most common malignancies in the world. The currently used chemotherapeutic drug for the treatment of EC is paclitaxel (PTX), the efficacy of which is affected by the development of drug resistance. The present study aims to define the role of the long noncoding RNA (lncRNA) DDX11-AS1 in the progression of EC with the involvement of PTX-resistant EC cells. First, EC and adjacent normal tissue samples were collected from 82 patients with EC, after which the expression levels of DDX11-AS1, TOP2A and TAF1 were determined. The results showed that DDX11-AS1, TOP2A and TAF1 were highly expressed in EC tissues, and there was a positive correlation between the expression levels of DDX11-AS1 and TOP2A. A PTX-resistant EC cell line was constructed. Next, we evaluated the effects of DDX11-AS1 and TOP2A on the resistance of EC cells to PTX, and the regulatory relationships between DDX11-AS1, TOP2A and TAF1 were investigated. DDX11-AS1 could promote TOP2A transcription via TAF1, and the knockdown of TOP2A or DDX11-AS1 could increase the sensitivity of EC cells to PTX. The effect of DDX11-AS1 on the growth of PTX-inhibited tumors was confirmed using a tumor formation assay in nude mice. It was verified that knocking down DDX11-AS1 reduced the expression level of TOP2A and inhibited tumor growth. In conclusion, our findings suggest that DDX11-AS1 knockdown results in reduced resistance of EC cells to PTX by inhibiting TOP2A transcription via TAF1. Therefore, DDX11-AS1 knockdown could be a promising therapeutic strategy for EC.

The existing solar heating system has high cost and a poor economy and is difficult to popularize because it needs a large area of solar collector and a volume of storage tank. Although many researchers attempted to optimize the system, it still could not reduce the initial cost significantly. To solve this problem, this paper presented a novel heating strategy for a specific commercial building and optimized it in term of economy. The novel strategy adopts a time-share heating method to reduce the initial cost and operating cost according to the heating requirement of the specific commercial building. In this study, a general model of a solar heating system based on TRNSYS was established. The combined effect of collector area, storage tank volume and electricity price on the economy was analyzed. The optimal matching ratio between storage tank volume and the collector area was obtained, and the heating performance in optimal matching was evaluated. The results showed that when the electricity price is $ 0.12, Vt/Ac = 0.05 has the maximum net present value (NPV), which has good economy with 6 years of payback period. This study presented an effective approach to solve the economic problem of solar heating.

In order to enhance the heat transfer performance and decrease the refrigerant charge of R290 in condensers, this paper numerically studied the condensation and refrigerant charge of R290 in minichannels (not the entire system) with different diameters to analyze the effect of diameter on them. The VOF multiphase flow model and SST k − ω turbulence model were used for 3D transient calculation in the simulation. The simulation results show that the diameter has a remarkable effect on the flow pattern, heat transfer coefficient, friction pressure drop and refrigerant charge. When the mass flux is small, a remarkable eddy current appears between vapor and liquid on the circular section, which can sharply enhance the heat transfer. At high vapor quality (x>0.8), the heat transfer coefficient and frictional pressure drop do not almost increase and even decrease with the increase of vapor quality under some working conditions, which is due to the influence of wall effect. Under the same heat transfer rate and heat transfer temperature difference, with the decrease of diameter, the maximum reduction of refrigerant charge reaches 94.8%. But when the diameter is reduced to a certain value, continuing to reduce the diameter will have little effect on the refrigerant charge.

As an ideal pollution-free refrigerant, R290 has been acceleratingly widely used. It is important to enhance the heat transfer performance and decrease the refrigerant charge of R290 in heat exchangers for its flammable and explosive properties. For this purpose, the research on condensation flow and refrigerant charge of R290 in a minichannel with different inclined angles is numerically carried out to obtain the optimal inclined angle. In the simulation, the VOF multiphase flow model and SST k − ω turbulence model are used for transient calculation, and the effect of surface tension is analyzed. The results show that as the inclined angle increases, heat transfer coefficient and frictional pressure drop increase. For heat transfer coefficient and refrigerant charge, the optimal inclined angle is 90° (downward flow), which is different from the existing results of R134a in a large channel. When G = 100, 200 kg/(m2s), at high vapor quality (x>0.8), heat transfer coefficient and frictional pressure drop almost do not increase with the increase of vapor quality. With the increase of inclined angle and mass flux, the refrigerant charge of R290 in a minichannel shows a downward trend. The maximum reduction is about 8% under the same heat transfer rate and heat transfer temperature difference. Therefore, changing the inclined angle is an effective approach to reduce the refrigerant charge of R290 in minichannel heat exchangers.

As a key component of energy absorption system, the performance of collector/evaporator directly affects the performance of the direct-expansion solar-assisted heat pump system. However, the existing researches main paid attention to the heat pump system performance using this kind of heat exchanger, while little of them are related to the heat transfer characteristics of this heat exchanger. Therefore, the heat transfer characteristics of a finned tube used in the collector/evaporator under solar radiation are theoretically analyzed in this work, the theoretical expression of finned tube temperature field is obtained, and the accuracy of the theoretical solution is validated by simulation. Theoretical study on how various factors affect heat transfer characteristics of finned tube are carried out. It is found that the heat transfer of fin unexposed to sunlight can be adversely affected by solar radiation, and with the increase of the convective heat transfer coefficient and diameter of copper tube, the negative influence of solar radiation are effectively reduced. Under larger fin height and solar radiation condition, increasing convective heat transfer coefficient on the aluminum fin surface do not increase the air heat absorbed by finned tube, but release more heat into environment. This study can theoretically guide the design and optimization of collector/evaporator.

Background: Genome-wide sequencing investigations have identified numerous long noncoding RNAs (lncRNAs) among mammals, many of which exhibit aberrant expression in cancers, including esophageal squamous cell carcinoma (ESCC). Herein, this study elucidates the role and mechanism by which LINC01419 regulates the DNA methylation of glutathione S-transferase pi 1 (GSTP1) in relation to ESCC progression and the sensitivity of ESCC cells to 5-fluorouracil (5-FU). Methods: LINC01419 and GSTP1 levels were quantified among 38 paired ESCC and adjacent tissue samples collected from patients with ESCC. To ascertain the contributory role of LINC01419 in the progression of ESCC and identify the interaction between LINC01419 and GSTP1 promoter methylation, LINC01419 was overexpressed or silenced, and the DNA methyltransferase inhibitor 5-Aza-CdR was treated. Results: Data from the GEO database (GSE21362) and the Cancer Genome Atlas displayed elevated levels of LINC01419 and downregulated levels of GSTP1 in the ESCC tissues and cells. The silencing of LINC01419 led to decreased proliferation, increased apoptosis, and enhanced sensitivity to 5-FU in ESCC cells. Notably, LINC01419 could bind to the promoter region of the GSTP1 gene, resulting in elevated GSTP1 methylation and reduced GSTP1 levels via the recruitment of DNA methyltransferase among ESCC cells, whereby ESCC progression was stimulated accompanied by reduced ESCC cell sensitivity to 5-FU. GSTP1 demethylation by 5-Aza-CdR was observed to reverse the effects of LINC01419 overexpression in ESCC cells and the response to 5-FU. Conclusion: Highly expressed LINC01419 in ESCC promotes GSTP1 methylation, which ultimately acts to promote the event of ESCC and diminish the sensitivity of ESCC cells to 5-FU, highlighting a novel potential strategy to improve 5-FU-based chemotherapy in ESCC.

This study was conducted to investigate the biomarkers that appear to be correlated with cancer-related fatigue (CRF) and the adverse reactions (ADRs) to chemotherapy. A total of 100 lung cancer patients were selected and CRF prior to and following chemotherapy was evaluated. The plasma levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1 and the level of 17-hydroxycorticosteroid (17-OHCS) in the urine were analyzed and correlated with CRF and the ADRs associated with chemotherapy. The incidence of CRF was found to be 88.0% and ADRs following chemotherapy occurred in 15.0% of the patients. An increase in the TNF-α and IL-1 levels was detected in patients with CRF. The level of 17-OHCS in the urine was found to be elevated in cases that experienced ADRs following chemotherapy. In conclusion, CRF is closely correlated with increased plasma levels of TNF-α and IL-1. Furthermore, an abnormally elevated 17-OHCS level in the urine may be an important indicator predicting ADR development following chemotherapy.