The internal and external exergy efficiencies are adopted to analyze the impact of working fluids on the performance of the organic Rankine cycle, and a simplified internal exergy efficiency model is ...proposed to indicate this impact. The calculation results show that the thermophysical properties of the working fluid have little impact on internal exergy efficiency, but they do play an important role in determining external exergy efficiency. Under the same heat source, the internal exergy efficiency of the ORC (organic Rankine cycle) will increase for all working fluids, whereas the characteristics of the external exergy efficiency exhibit parabolic-like curves with the increase of evaporation temperature. By taking exergy efficiency as an objective function, an optimal analysis based on a genetic algorithm is conducted to illuminate the impact of working fluids on internal and external exergy efficiencies. The optimization results show that the selection of working fluids depends greatly on optimal evaporation temperature. Working fluids with lower critical temperature lead to a higher optimal evaporation temperature, which results in higher overall exergy efficiency. Therefore, the present study on selecting working fluids for organic Rankine cycle systems may have potential application in low grade waste heat recovery systems.
•The internal and external exergy efficiencies are studied.•The internal exergy efficiency model is proposed and compared with theoretical data.•The thermophysical properties of the working fluid have little impact on internal exergy efficiency.•The working fluid's properties play an important role in determining external exergy efficiency.•Low Tcr working fluid is preferable under optimal operation condition of ORC.
Ion transport peptide (ITP) and its alternatively spliced homologous ITP‐like (ITPL) products play important roles in various insect developmental processes. We found for the first time that ...alternative 5' untranslated regions (5' UTRs) of ITPL (NilluITPLs‐1, ‐2, ‐3 and ‐4) control spatiotemporal expression in the brown planthopper, Nilaparvata lugens, as demonstrated by reverse‐transcription quantitative PCR. By using an alternative 5' UTR, NilluITPL‐1 was expressed exclusively in the male reproductive system, resulting in the production of the NilluITPL seminal fluid protein. Interestingly, NilluITPLs‐3 and −4 were expressed exclusively in the integument, indicating a specialized function for NilluITPL during ecdysis and eclosion. We investigated the functions of NilluITP and NilluITPL using RNA interference (RNAi). We did not observe apparent phenotypes when expression of NilluITPLs was suppressed. However, when NilluITP expression was suppressed, the insect exhibited melanism and failed wing expansion, indicating that NilluITP is a neuropeptide associated with wing expansion in addition to bursicon. Additionally, in contrast to bursicon, the insects showed increased melanism when NilluITP was eliminated by RNAi. Unlike previous studies of ITP/ITPL in other species, NilluITP was very important in the control of N. lugens postecdysial behaviours but was not critical during ecdysis. Thus, the functions of ITP and ITPL are more complex in insects than previously thought.
An analytical relationship between the reduced modulus
E
r and hardness
H for solid materials is established based on the conventional depth-sensing indentation method of Oliver and Pharr. It is ...found that the two properties are related through a material parameter that is defined as the recovery resistance
R
s. This parameter is shown to represent the energy dissipation during indentation. Based on indentation measurements with the use of a Berkovich indenter, the relationship is given as
E
r
=
0.6647
HR
s
. Also presented is a simple set of procedures to determine the area of indent. The procedures require three measured quantities, i.e., the peak load and corresponding displacements as well as the depth of residual indentation, but do not require complicated curve fitting process and regression analysis which themselves involve the specimen material. Nano-indentation tests were conducted using a Berkovich indenter on five materials spanning a wide range of hardness and plasticity. Experimental results revealed two important features: (a) the reduced modulus predicted by the new
E
r–
H relationship is the same as that obtained by the conventional method; (b) the elastic modulus and hardness values determined by the simple set of procedures are comparable to those obtained by using the conventional method.
Abstract Resveratrol is a natural polyphenol found in grapes and wine and has been associated with protective effects against cardiovascular diseases. In vitro , both resveratrol preconditioning ...(RPC) and ischemic preconditioning (IPC) require activation of sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD+ )-dependent deacetylase, to induce neuroprotection against cerebral ischemia. In the present study, we tested two hypotheses: (a) that neuroprotection against cerebral ischemia can be induced by RPC in vivo ; and (b) that RPC neuroprotection involves alterations in mitochondrial function via the SIRT1 target mitochondrial uncoupling protein 2 (UCP2). IPC was induced by 2 min of global ischemia (temporary bilateral carotid artery occlusion with hypotension), and RPC, by i.p. injection of resveratrol at 10, 50 and 100 mg/kg dosages. Forty-eight hours later, we compared the neuroprotective efficacy of RPC and IPC in vulnerable cornu ammonis 1 hippocampal pyramidal neurons using a rat model of asphyxial cardiac arrest (ACA). SIRT1 activity was measured using a SIRT1-specific fluorescent enzyme activity assay. In hippocampal mitochondria isolated 48 h after IPC or RPC, we measured UCP2 levels, membrane potential, respiration, and the mitochondrial ATP synthesis efficiency (ADP/O ratio). Both IPC and RPC induced tolerance against brain injury induced by cardiac arrest in this in vivo model. IPC increased SIRT1 activity at 48 h, while RPC increased SIRT1 activity at 1 h but not 48 h after treatment in hippocampus. Resveratrol significantly decreased UCP2 levels by 35% compared to sham-treated rats. The SIRT1-specific inhibitor sirtinol abolished the neuroprotection afforded by RPC and the decrease in UCP2 levels. Finally, RPC significantly increased the ADP/O ratio in hippocampal mitochondria reflecting enhanced ATP synthesis efficiency. In conclusion, in vivo resveratrol pretreatment confers neuroprotection similar to IPC via the SIRT1–UCP2 pathway.
Avermectins are major antiparasitic agents used commercially in animal health, agriculture and human infections. To improve the fermentation efficiency of avermectins, for the first time a plasma jet ...generated by a novel atmospheric pressure glow discharge (APGD) was employed to generate mutations in Streptomyces avermitilis. The APGD plasma jet, driven by a radio frequency (RF) power supply with water-cooled and bare-metallic electrodes, was used as a new mutation method to treat the spores of S. avermitilis. The plasma jet yielded high total (over 30%) and positive (about 21%) mutation rates on S. avermitilis, and a mutated strain, designated as G1-1 with high productivity of avermectin B1a and genetic stability, was obtained. Because of the low jet temperature, the high concentrations of the chemically reactive species and the flexibility of its operation, the RF APGD plasma jet has a strong mutagenic effect on S. avermitilis. This is a proof-of-concept study for the use of an RF APGD plasma jet for inducing mutations in microbes. We have shown that the RF APGD plasma jet could be developed as a promising and convenient mutation tool for the fermentation industry and for use in biotechnology research.
Non-alcoholic fatty liver diseases (NAFLD) are liver diseases which are strongly associated with obesity. The incidence of NAFLD has been gradually increased in recent years. According to different ...pathology of the liver, NAFLD include three disease states: simple fatty liver, hepatitis (nonalcoholic steatohepatitis, NASH) and fatty liver cirrhosis. The accumulations of fat around the internal organs, which secrete a wide range of adipokines, such as interleukin-6, contribute the development and progress of NAFLD in obesity. In addition, the liver has been recognized as an immune organ containing several immune cells, for instance, inherited macrophages in the live (kupffer cells), nature killer cells, T lymphocytes, T regulatory cells (Tregs), myeloid-derived suppressor cells (MDSCs), and dendritic cells. These immune cells secret a number of cytokines, such as tumor necrosis factor (TNF-α) and monocyte chemoattractant protein (MCP-1), play important roles in the development of NAFLD. Moreover, a high level
In this paper, the wake control of a circular cylinder by dual plates symmetrically attached at the rear surface is numerically investigated within the laminar flow regime. The two flat plates are ...arranged in parallel form, and the attachment angle is varied in the range θf=0–90°. In comparison to the use of a single splitter plate, the dual plates cause increased drag reduction and stronger wake suppression at relatively shorter plate lengths. It is shown that the attachment angle has a crucial effect on the control efficiency, and the most effective range associated with the maximum drag reduction is between 40°≤θf≤50°. Within this regime, the free shear layers reattach on the outside surface of the control plates. The potential mechanism responsible for the wake control is suggested based on a comparison with other passive control configurations.
Although the use of sorafenib appears to increase the survival rate of renal cell carcinoma (RCC) patients, there is also a proportion of patients who exhibit a poor primary response to sorafenib ...therapy. It is therefore critical to elucidate the mechanisms underlying sorafenib resistance and find representative biomarkers for sorafenib treatment in RCC patients. Herein, we identified a long non-coding RNA referred to as lncRNA-SRLR (sorafenib resistance-associated lncRNA in RCC) that is upregulated in intrinsically sorafenib-resistant RCCs. lncRNA-SRLR knockdown sensitized nonresponsive RCC cells to sorafenib treatment, whereas the overexpression of lncRNA-SRLR conferred sorafenib resistance to responsive RCC cells. Mechanistically, lncRNA-SRLR directly binds to NF-κB and promotes IL-6 transcription, leading to the activation of STAT3 and the development of sorafenib tolerance. A STAT3 inhibitor and IL-6-receptor antagonist both restored the response to sorafenib treatment. Moreover, a clinical investigation demonstrated that high levels of lncRNA-SRLR correlated with poor responses to sorafenib therapy in RCC patients. Collectively, lncRNA-SRLR may serve as not only a predictive biomarker for inherent sorafenib resistance but also as a therapeutic target to enhance responses to sorafenib in RCC patients.
PDF
