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The maldistribution of working fluid is one of the issues in heat exchangers that causes a reduction in performance of not only the heat exchanger but also the entire HVAC system. One of the methods to reduce such maldistribution is to improve manifold design to evenly distribute the flow. In the present work, an advanced maldistribution reduction manifold, which was based on a preliminary maldistribution reduction manifold, was designed to further improve the flow distribution in the heat exchanger. In the design, spiral baffles are used to create vortices in the tubes to regulate the flow in each tube. The design also keeps the tubes away from the manifold inlet to avoid direct flow from the inlet. Due to the complexity, the design of the advanced maldistribution reduction manifold is for AM only, which cannot be fabricated by traditional manufacturing. To evaluate the design, a computational fluid dynamic model is developed to study flow distribution in heat exchanger manifolds. The simulation results reveal that the relative standard deviation of the tubes in the advanced maldistribution reduction design is half of the preliminary maldistribution reduction design and about 1/20 of the reference design.

The Hewlett Packard Enterprise–Cray EX Frontier is the world’s first and fastest exascale supercomputer, hosted at the Oak Ridge Leadership Computing Facility in Tennessee, United States. Frontier is a significant electricity consumer, drawing 8–30 MW; this massive energy demand produces significant waste heat, requiring extensive cooling measures. Although harnessing this waste heat for campus heating is a sustainability goal at Oak Ridge National Laboratory (ORNL), the 30 °C–38 °C waste heat temperature poses compatibility issues with standard HVAC systems. Heat pump systems, prevalent in residential settings and some industries, can efficiently upgrade low-quality heat to usable energy for buildings. Thus, heat pump technology powered by renewable electricity offers an efficient, cost-effective solution for substantial waste heat recovery. However, a major challenge is the absence of benchmark data on high-performance computing (HPC) heat generation and waste heat profiles. This paper reports power demand and waste heat measurements from an ORNL HPC data centre, aiming to guide future research on optimizing waste heat recovery in large-scale data centres, especially those of HPC calibre.

Radix Bupleuri (root of Bupleurum spp.) is an important medicinal herb. Its lateral root number is one of the decisive factors that influence the content of a major bioactive component, saikosaponin. To identify genes associated with content and total yield of saikosaponin, it is of key importance to select stable references in gene expression analyses using quantitative real-time polymerase chain reaction (qRT-PCR). In this study, 18 candidate reference genes were selected and evaluated through their expression stability during the lateral root development in tissue samples from B. chinense DC., B. falcatum L. and B. scorzonerifolium Willd. The GeNorm, NormFinder and Bestkeeper methods were used for selecting stably expressed internal controls in the three Bupleurum species. These results revealed that, among these 18 candidate reference genes, ADF7 showed the best performance in all the experimental systems. ADF5 and ADF1b could also be proposed as suitable reference genes for gene expression studies. This study supplied more candidate reference genes to monitor the content and yield of saikosaponin during lateral roots growth in the Bupleurum genus.

Objectives: The etiology of myocardial ischemia/reperfusion (I/R) injury is multifactorial, but activation of the innate immune system and the resulting inflammatory response are important components of I/R injury. The aim of this study was to investigate the protective effect of a hemoglobin-based oxygen carrier (HBOC) on cold I/R heart and to explore the underlying mechanisms. Methods: Isolated Sprague-Dawley rat hearts were perfused in the Langendorff mode. After 30 min of basal perfusion, rat hearts were arrested with histidine-tryptophan-ketoglutarate solution (HTKs) with or without an HBOC and hypothermically stored (4°C) for 9 or 14 h, followed by 2 h of reperfusion. Results: Compared with HTKs alone, the HBOC in HTKs greatly improved heart contraction and decreased infarct size, necrosis and apoptosis, which was related to the reduced expression of Toll-like receptor 2 (TLR 2), TLR 4, TNF-α, IL-1β and nuclear factor-ĸB (NF-ĸB) activation. Conclusions: Our results demonstrated that the HBOC protected isolated rat heart from cold I/R injury and this protection was associated with attenuation of the expression of the TLR 2 and TLR 4/NF-ĸB signaling pathway, which may down-regulate the inflammatory response.

Jiuzhaigou, characterized by its magnificent waterscapes and subalpine karstic features, is both a World Heritage Site and a World Biosphere Reserve in southwestern China. In recent years, this unique ecosystem has shown signs of stress due to increasing tourism activities within the reserve. The various routine methods, which monitor physical and chemical properties, do not fully reflect water quality in the subalpine and alpine lakes, while the indicators using aquatic organisms to evaluate the water quality or status of the subalpine lakes are poorly reported. Thus, in this study, benthic diatoms from multiple habitats in Jiuzhaigou were sampled and assessed for water quality monitoring. Canonical Correspondence Analysis （CCA） showed that the canonical coefficients for elevation, water temperature and total nitrogen on the first Canonical Corresnondence Analysis axis were -0.84. 0.78 and -0.53, respectively, environmental variables associated with the distribution patterns of benthic diatoms. The dominance of diatom taxa indicative of nutrient enrichment indicates a clear trend toward eutrophication in the Pearl Shoal and Colorful Lake, two of the sites mostly visited by tourists. It was observed that the effect of the type of substratum on diatom community composition is not significant in subalpine lakes. The most dominant species in Jiuzhaigou lakes are the genera Achnanthes, Fragilaria, CymbeUa, Cocconeis, Diatoma and Denticula. In combination with dominant and sensitive species in the benthic diatom communities, CCA and CA methods can be used to evaluate the impact of human activities on subalpine karstic lakes. The dominance of diatom taxa is indicative of nutrient enrichment and the results of CCA and CA indicate a clear trend toward eutrophication in the Pearl Shoal and Colorful Lake, two of the sites mostly visited by tourists.

Side channel analysis（SCA） focuses on attacking cryptographic algorithm implementations by col- lecting leaked information and analyzing the correlation between the leaked and key information in the crypto- graphic system. Currently, SCA is the main threat to cryptographic implementations, with DPA （differential power analysis） and DFA （differential fault analysis） being two of the most threatening types of SCA. However, the existing countermeasures against DPA and DFA have shortcomings and can hardly protect cipher designs perfectly. Based on a comprehensive analysis of DPA and DFA, this paper proposes a new idea of using an evo- lutionary cipher （EVOC） against DPAs based on the model proposed by Kocher, and several different new types of DFAs. In fact, an EVOC is a kind of dynamic cipher designing method. Moreover, combined with intelligent searching algorithms and cryptography design policies, EVOCs utilize the dynamic and unpredictable properties of TRNG （a truly random number generator） to ensure cipher design at a high level of security. Therefore, with an EVOC we could design cryptography algorithms with high security to resist mathematical analysis as well as DPAs and DFAs. This paper analyzes and proves the security, efficiency, cost, and original features of EVOCs against DPA and DFA both theoretically and experimentally. Compared with existing countermeasures against SCAs, EVOCs use dynamic non-linear operations to destroy the bases of DPA and DFA. At the algorithm level, EVOCs are more efficient than other resistance methods. Based on the theory and experiments, this paper proposes certain modifications to the EVOC in the AES （advanced encryption standard） algorithm, which can be referenced by other dynamic designs of cryptographic algorithms.

This paper describes a high-throughput method for developing physically modified chitosan membranes to probe the cellular behavior of MDCK epithelial cells and HIG-82 fibroblasts adhered onto these modified membranes. To prepare chitosan membranes with micro/nanoscaled features, we have demonstrated an easy-to-handle, facile approach that could be easily integrated with IC-based manufacturing processes with mass production potential. These physically modified chitosan membranes were observed by scanning electron microscopy to gain a better understanding of chitosan membrane surface morphology. After MDCK cells and HIG-82 fibroblasts were cultured on these modified chitosan membranes for various culture durations (i.e. 1, 2, 4, 12 and 24 h), they were investigated to decipher cellular behavior. We found that both cells preferred to adhere onto a flat surface rather than on a nanopatterned surface. However, most (> 80%) of the MDCK cells showed rounded morphology and would suspend in the cultured medium instead of adhering onto the planar surface of negatively nanopatterned chitosan membranes. This means different cell types (e.g. fibroblasts versus epithelia) showed distinct capabilities/preferences of adherence for materials of varying surface roughness. We also showed that chitosan membranes could be re-used at least nine times without significant contamination and would provide us consistency for probing cell-material interactions by permitting reuse of the same substrate. We believe these results would provide us better insight into cellular behavior, specifically, microscopic properties and characteristics of cells grown under unique, nanopatterned cell-interface conditions.

Scar formation after spinal cord injury is regarded as an obstacle to axonal regeneration and functional recovery.Epothilone B provides moderate microtubule stabilization and is mainly used for anti-tumor therapy.It also reduces scar tissue formation and promotes axonal regeneration after spinal cord injury.The aim of the present study was to investigate the effect and mechanism of the microtubule-stabilizing reagent epothilone B in decreasing fibrotic scarring through its action on pericytes after spinal cord injury.A rat model of spinal cord injury was established via dorsal complete transection at the T10 vertebra.The rats received an intraperitoneal injection of epothilone B（0.75 mg/kg） at 1 and 15 days post-injury in the epothilone B group or normal saline in the vehicle group.Neuron-glial antigen 2,platelet-derived growth factor receptor β,and fibronectin protein expression were dramatically lower in the epothilone B group than in the vehicle group,but β-tubulin protein expression was greater.Glial fibrillary acidic protein at the injury site was not affected by epothilone B treatment.The Basso,Beattie,and Bresnahan locomotor scores were significantly higher in the epothilone B group than in the vehicle group.The results of this study demonstrated that epothilone B reduced the number of pericytes,inhibited extracellular matrix formation,and suppressed scar formation after spinal cord injury.

The Thermo-Calc software was employed to calculate the equilibrium phase of 22Cr-27Ni-2Ti-Al austenitic valve steel, and the Laves phase in this steel was investigated after solid solution and aging by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Results show that the microstructure of the experimental steel consists of γ, γ′, Laves and NbC. Laves phases mainly precipitate on grain boundaries, with granular and fibrous morphologies. The size of the granular Laves phase is about 50–600 nm, and the fibrous Laves phase is composed of short strip Laves phases which are 300–600 nm in length and 50–150 nm in width. These two morphologies of Laves phase coarsen with increasing aging temperature, and this steel possesses the highest strength and hardness at aging temperature of 760 °C.

The Thermo-Calc software was employed to calculate the equilibrium phase of 22Cr-27Ni-2Ti-Al austenitic valve steel,and the Laves phase in this steel was investigated after solid solution and aging by means of scanning electron microscopy( SEM),transmission electron microscopy( TEM) and X-ray diffraction( XRD).Results show that the microstructure of the experimental steel consists of γ,γ’,Laves and Nb C.Laves phases mainly precipitate on grain boundaries,with granular and fibrous morphologies.The size of the granular Laves phase is about 50-600 nm,and the fibrous Laves phase is composed of short strip Laves phases which are 300-600 nm in length and 50-150 nm in width.These two morphologies of Laves phase coarsen with increasing aging temperature,and this steel possesses the highest strength and hardness at aging temperature of 760 ℃.