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  • Author: You-Rong Li x
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Abstract

On the basis of linear non-equilibrium thermodynamic theory, exergy transfer analyses of laminar and turbulent forced convection are conducted in terms of external flows over a flat plate. Two kinds of non-dimensional concepts involving the definition of the local and mean exergy transfer Nusselt number and non-dimensional exergy flux are incorporated into exergy transfer analysis. The new analytical expressions for the local and mean exergy transfer Nusselt number and non-dimensional exergy flux are adopted to describe the exergy transfer characteristics over a flat plate. By taking air as working fluid, the influences of flat plate geometry, Reynolds number, and other operating parameters on the exergy transfer Nusselt number and non-dimensional exergy flux are examined. It is shown how the flow geometric parameters and Reynolds number, etc., may be selected in order to maximize the exergy utilization associated with a specific external convection process. In addition, the results obtained from exergy transfer analysis are compared with those obtained from traditional heat transfer analysis.

Abstract

Background: Previous studies suggest that a variable number of tandem repeats polymorphism in the second intron of the interleukin-1 receptor antagonist gene and two single nucleotide polymorphisms at positions −511 and +3954 of the interleukin-1β (IL-1B) gene are associated with an increased risk of autoimmune diseases. In the present study, we evaluated associations between these genetic factors and an increased risk of rheumatoid arthritis (RA) in a population from Northwest China.

Methods: A total of 240 patients with RA and 227 healthy controls from Northwest China were investigated using PCR and PCR-restriction fragment length polymorphism. Genotype and allele distributions and haplotype construction were analyzed.

Results: The genotype and allele distributions of IL-1B +3954 and IL-1RN polymorphisms were significantly different in RA patients compared to controls (p<0.001 and p<0.001; p=0.028, p=0.023, respectively). Significant differences were also observed between the RA and control groups for the haplotypes IL-1B –511C/+3954C/IL-1RN *1, IL-1B –511C/+3954T/IL-1RN *1 and IL-1B –511T/+3954T/IL-1RN *1 [p=0.017, odds ratio (OR) 0.721, 95% confidence interval (CI) 0.551–0.944; p=0.030, OR 2.111, 95% CI 1.060–4.204; and p=0.029, OR 2.909, 95% CI 1.066–7.902, respectively].

Conclusions: These findings suggest that IL-1B +3954 and IL-1RN genetic polymorphisms are associated with a significantly increased risk of RA in this Chinese population.

Clin Chem Lab Med 2007;45:968–71.

Abstract.

This paper focuses on the research of an evaporator with a binary mixture of organic working fluids in the organic Rankine cycle. Exergoeconomic analysis and performance optimization were performed based on the first and second laws of thermodynamics, and the exergoeconomic theory. The annual total cost per unit heat transfer rate was introduced as the objective function. In this model, the exergy loss cost caused by the heat transfer irreversibility and the capital cost were taken into account; however, the exergy loss due to the frictional pressure drops, heat dissipation to surroundings, and the flow imbalance were neglected. The variation laws of the annual total cost with respect to the number of transfer units and the temperature ratios were presented. Optimal design parameters that minimize the objective function had been obtained, and the effects of some important dimensionless parameters on the optimal performances had also been discussed for three types of evaporator flow arrangements. In addition, optimal design parameters of evaporators were compared with those of condensers.

Abstract

The molecular mechanisms underlying cold-resistance in Prunus campanulata Maxim. (P. campanulata) are not fully understood. This study aimed to establish a full-length library and analyze expressed sequence tags (ESTs) to provide tools to investigate the mechanisms of P. campanulata growth at low temperatures. Based on the switching mechanism at 5’end of RNA transcript technology, a full-1ength cDNA library was generated from young leaves of P. campanulata after 72 h treatment at 1◦C, and a preliminary EST analysis was carried out. Quantitative reverse transcription polymerase chain reaction was used to assess the expression of selected cold-related genes. The cDNA library titer was 1.2 × 106 cfu/mL−1, with a recombinant rate of 96%. The average size of inserted cDNA fragments was 1.3 Kb. EST data revealed the existence of 834 clones representing a total of 667 unigenes, including 574 singletons and 93 contigs. Blast analysis identified 475 unigenes with known and putative functions. Based on similarity search and GO annotation, 84 unigenes were associated with “response to stimuli”, suggesting that cold stress induced significant alterations in gene expression in P. campanulata cultivated at 1◦C for 72 h. Interestingly, DRP, MYB, HSP, GPX and GA20-ox gene expression was significantly up-regulated in plants cultivated at low temperature, while transcript levels of TIL, CDPK were decreased. P. campanulata cultivating at low temperature express genes associated with “response to stimuli”, and in particular DRP, MYB, HSP, GPX and GA20-ox gene are up-regulated while TIL, CDPK are downregulated in response to low temperature-stress

Abstract

Objectives

Drug-laboratory test interactions (DLTIs) are one of the major sources of laboratory errors. Calcium dobesilate (CaD) interference on serum creatinine testing is a widespread problem that has long been ignored in China. A national EQA-based survey was launched to investigate the current status of CaD interference on creatinine routine methods used in China and enhance the education of CaD interference in clinical laboratories.

Methods

A descriptive survey was developed to characterize the status quo of Chinese laboratory professionals’ cognition to CaD interference. Four of survey samples which were spiked with/without interference additive were shipped to 175 participant laboratories. The target reference values from a reference measurement procedure were compared against the results from participating laboratories to evaluate the CaD interference on serum creatinine measurements using enzymatic method or Jàffe method.

Results

The lack of knowledge of DLTIs and the barriers to collect information from pharmacological and laboratory data systems had become the main problems on implementing DLTIs education in China. A significant negative influence of CaD on enzymatic method was observed regardless of measurement platforms. Jàffe method was generally free from interaction with CaD but showed poor precision and accuracy at low creatinine concentrations.

Conclusions

More efforts should be made to enhance the education of DLTIs in clinical laboratories in China.

Abstract

On the basis of the first and second laws of thermodynamics, the general expression of the number of entropy generation units of three-fluid heat exchangers with three thermal communications was derived. The effect of several non-dimensional design parameters on the number of entropy generation units of three-fluid heat exchangers was thoroughly discussed. Furthermore, the detailed comparisons of results have been given for the arrangement of the parallel flow and the counter flow. It is shown that the variation tendencies of the number of entropy generation units with the ratio of the thermal resistances, ratio of the thermal capacities, and number of heat transfer units for the parallel-flow arrangement are different from those of the counter-flow arrangement. There exists an extremum of the number of entropy generation units for the counter-flow arrangement. In addition, the entropy generation for the counter flow is mostly smaller than that of the parallel flow under the same conditions.