Post-positioned gas spring enables ultra-high output power of hybrid thermoacoustic electric generators

High-capacity hybrid thermoacoustic electric generators (HTAEGs) are ideal in different small- and micro-scale energy systems, especially in space nuclear power systems. In this work, an HTAEG with a post-positioned gas spring is proposed. To demonstrate the superiority of the gas-spring-post-positioned design on high-capacity HTAEGs, an HTAEG prototype is modeled, built, and tested from the perspective of thermoacoustics accordingly. Experimental results demonstrate an output electric power of 15.0 kW. Furthermore, it could achieve the highest efficiency of 39.2% with an output electric power of 11.1 kW. Given that a 15-kW power output is an ultra-high level on a single-piston HTAEG of this type to date, and the achieved efficiency on the prototype is also encouraging, this work marks an important milestone in the development of high-capacity HTAEGs. It also demonstrates that the gas-spring-post-positioned design has significant advantages and enormous potential for application

Accuracies of field CO2–H2O data from open-path eddy-covariance flux systems: assessment based on atmospheric physics and biological environment

Ecosystem CO2–H2O data measured by infrared gas analyzers in open-path eddy-covariance (OPEC) systems have numerous applications, such as estimations of CO2 and H2O fluxes in the atmospheric boundary layer. To assess the applicability of the data for these estimations, data uncertainties from analyzer measurements are needed. The uncertainties are sourced from the analyzers in zero drift, gain drift, cross-sensitivity, and precision variability. These four uncertainty sources are individually specified for analyzer performance, but so far no methodology exists yet to combine these individual sources into a composite uncertainty for the specification of an overall accuracy, which is ultimately needed. Using the methodology for closed-path eddy-covariance systems, this overall accuracy for OPEC systems is determined from all individual uncertainties via an accuracy model and further formulated into CO2 and H2O accuracy equations. Based on atmospheric physics and the biological environment, for EC150 infrared CO2–H2O analyzers, these equations are used to evaluate CO2 accuracy (±1.22 mgCO2 m−3, relatively ±0.19 %) and H2O accuracy (±0.10 gH2O m−3, relatively ±0.18 % in saturated air at 35 ∘C and 101.325 kPa). Both accuracies are applied to conceptual models addressing their roles in uncertainty analyses for CO2 and H2O fluxes. For the high-frequency air temperature derived from H2O density along with sonic temperature and atmospheric pressure, the role of H2O accuracy in its uncertainty is similarly addressed. Among the four uncertainty sources, cross-sensitivity and precision variability are minor, although unavoidable, uncertainties, whereas zero drift and gain drift are major uncertainties but are minimizable via corresponding zero and span procedures during field maintenance. The accuracy equations provide rationales to assess and guide the procedures. For the atmospheric background CO2 concentration, CO2 zero and CO2 span procedures can narrow the CO2 accuracy range by 40 %, from ±1.22 to ±0.72 mgCO2 m−3. In hot and humid weather, H2O gain drift potentially adds more to the H2O measurement uncertainty, which requires more attention. If H2O zero and H2O span procedures can be performed practically from 5 to 35 ∘C, the H2O accuracy can be improved by at least 30 %: from ±0.10 to ±0.07 gH2O m−3. Under freezing conditions, the H2O span procedure is impractical but can be neglected because of its trivial contributions to the overall uncertainty. However, the zero procedure for H2O, along with CO2, is imperative as an operational and efficient option under these conditions to minimize H2O measurement uncertainty.</p

Clinical characteristics and genetic analysis of a Chinese pedigree of type 2 diabetes complicated with interstitial lung disease

PurposeDiabetes mellitus is a systemic metabolic disorder which may target the lungs and lead to interstitial lung disease. The clinical characteristics and mechanisms of type 2 diabetes mellitus (T2DM) complicated with interstitial lung disease (ILD) have been studied. However, little work has been done to assess genetic contributions to the development of T2DM complicated with ILD.MethodA pedigree of T2DM complicated with ILD was investigated, and the whole genome re-sequencing was performed to identify the genetic variations in the pedigree. According to the literature, the most valuable genetic contributors to the pathogenesis of T2DM complicated with ILD were screened out, and the related cellular functional experiments were also performed.ResultsA large number of SNPs, InDels, SVs and CNVs were identified in eight subjects including two diabetic patients with ILD, two diabetic patients without ILD, and four healthy subjects from the pedigree. After data analysis according to the literature, MUC5B SNP rs2943512 (A &gt; C) was considered to be an important potentially pathogenic gene mutation associated with the pathogenesis of ILD in T2DM patients. In vitro experiments showed that the expression of MUC5B in BEAS-2B cells was significantly up-regulated by high glucose stimulation, accompanied by the activation of ERK1/2 and the increase of IL-1β and IL-6. When silencing MUC5B by RNA interference, the levels of p-ERK1/2 as well as IL-1β and IL-6 in BEAS-2B cells were all significantly decreased.ConclusionThe identification of these genetic variants in the pedigree enriches our understanding of the potential genetic contributions to T2DM complicated with ILD. MUC5B SNP rs2943512 (A &gt; C) or the up-regulated MUC5B in bronchial epithelial cells may be an important factor in promoting ILD inT2DM patients, laying a foundation for future exploration about the pathogenesis of T2DM complicated with ILD

Structural Analysis of Heparin-Derived 3- O -Sulfated Tetrasaccharides: Antithrombin Binding Site Variants

Heparin is a polysaccharide that is widely used as an anticoagulant drug. The mechanism for heparin’s anticoagulant activity is primarily through its interaction with a serine protease inhibitor, antithrombin III (AT), that enhances its ability to inactivate blood coagulation serine proteases, including thrombin (factor IIa) and factor Xa. The AT-binding site in the heparin is one of the most well-studied carbohydrate-protein binding sites and its structure is the basis for the synthesis of the heparin pentasaccharide drug, fondaparinux. Despite our understanding of the structural requirements for the heparin pentasaccharide AT-binding site, there is a lack of data on the natural variability of these binding sites in heparins extracted from animal tissues. The present work provides a detailed study on the structural variants of the tetrasaccharide fragments of this binding site afforded following treatment of a heparin with heparin lyase II. The 5 most commonly observed tetrasaccharide fragments of the AT-binding site are fully characterized, and a method for their quantification in heparin and low-molecular-weight heparin products is described

Heparan Sulfate Domains Required for Fibroblast Growth Factor 1 and 2 Signaling through Fibroblast Growth Factor Receptor 1c

A small library of well defined heparan sulfate (HS) polysaccharides was chemoenzymatically synthesized and used for a detailed structure-activity study of fibroblast growth factor (FGF) 1 and FGF2 signaling through FGF receptor (FGFR) 1c. The HS polysaccharide tested contained both undersulfated (NA) domains and highly sulfated (NS) domains as well as very well defined non-reducing termini. This study examines differences in the HS selectivity of the positive canyons of the FGF12-FGFR1c2 and FGF22-FGFR1c2 HS binding sites of the symmetric FGF2-FGFR2-HS2 signal transduction complex. The results suggest that FGF12-FGFR1c2 binding site prefers a longer NS domain at the non-reducing terminus than FGF22-FGFR1c2. In addition, FGF22-FGFR1c2 can tolerate an HS chain having an N-acetylglucosamine residue at its non-reducing end. These results clearly demonstrate the different specificity of FGF12-FGFR1c2 and FGF22-FGFR1c2 for well defined HS structures and suggest that it is now possible to chemoenzymatically synthesize precise HS polysaccharides that can selectively mediate growth factor signaling. These HS polysaccharides might be useful in both understanding and controlling the growth, proliferation, and differentiation of cells in stem cell therapies, wound healing, and the treatment of cancer

Inhibition of Glutathione Synthesis via Decreased Glucose Metabolism in Stored RBCs

Background/Aims: Although red blood cells (RBCs) transfusions can be lifesaving, they are not without risk. RBCs storage is associated with the abnormal metabolism of glutathione (GSH), which may increase the risk of the oxidative damage of RBCs after transfusion. The responsible mechanisms remain unknown. Methods: We determined the L-cysteine efflux and influx by evaluating the changes of free -SH concentrations in stored RBCs. The glutamate cysteine ligase (GCL) activities and protein content in stored RBCs was determined by fluorescence assay and western blotting. In addition, the glucose metabolism enzyme activity of RBCs was measured by spectrophotometric assay under in vitro incubation conditions. Results: We found that both L-cysteine transport and GCL activity significantly declined, thereby inducing the dysfunction of GSH synthesis during blood storage, which could be attenuated by ATP supplement and DTT treatment. In addition, the glycometabolic enzyme (G6PDH, HK, PK and LDH) activity significantly decreased after 6 weeks storage. Oxidant stress-induced dysfunction in glucose metabolism was the driving force for decreased GSH synthesis during storage. Conclusion: These experimental findings reflect an underlying molecular mechanism that oxidant stress induced glucose metabolism dysfunction contribute to decreased GSH synthesis in stored RBCs

Static pressure reset control strategy for roof fans in centralized cooking exhaust systems

Excessive static pressure and inadequate flow rate at each terminal of the centralized cooking exhaust systems contribute to poor indoor air quality in kitchens. Roof fans can improve the ventilation performance of centralized cooking exhaust system, but the optimal control strategy for roof fans is currently unavailable. This paper proposes a static pressure reset control strategy for variable frequency operation of roof fans that follows the law of normal distribution of simultaneous operating rate. The effect of the roof fan on the static pressure and flow rate distribution in a centralized cooking exhaust system with multiple power sources of range hoods is investigated. The relationship between simultaneous cooking rate and the appropriate set point of the roof fan is determined using experimental and simulation methods. The results show that the proposed static pressure reset control strategy for roof fans has improved control performance and significant potential for energy savings

Impact of Packet Size on Performance of TCP traffic with Small Router buffers

In this paper, we research the impact of packet size on the performance of TCP traffic with small router buffers. First of all, we established a simple model which had two TCP flows, combined with the queue management mechanism in a router and analyzed the effect on TCP packet loss performance of variable packet sizes. Secondly, the corresponding network topology was established based on the NS2 simulation software. And the correctness of the model was verified by experiments