Cloning, Heterologous Expression, and Characterization of a βκ-Carrageenase From Marine Bacterium Wenyingzhuangia funcanilytica: A Specific Enzyme for the Hybrid Carrageenan–Furcellaran

Carrageenan is a group of important food polysaccharides with high structural heterogeneity. Furcellaran is a typical hybrid carrageenan, which contains the structure consisted of alternative beta-carrageenan and kappa-carrageenan motifs. Although several furcellaran-hydrolyzing enzymes have been characterized, their specificity for the glycosidic linkage was still unclear. In this study, we cloned, expressed, and characterized a novel GH16_13 furcellaran-hydrolyzing enzyme Cgbk16A_Wf from the marine bacterium Wenyingzhuangia fucanilytica CZ1127. Cgbk16A_Wf exhibited its maximum activity at 50 degrees C and pH 6.0 and showed high thermal stability. The oligosaccharides in enzymatic products were identified by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR) spectroscopy. It was confirmed that Cgbk16A_Wf specifically cleaves the beta-1,4 linkages between beta-carrageenan and kappa-carrageenan motifs from non-reducing end to reducing end. Considering the structural heterogeneity of carrageenan and for the unambiguous indication of the specificity, we recommended to name the furcellaran-hydrolyzing activity represented by Cgbk16A as beta kappa-carrageenase instead of furcellaranase

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Research on new technology for offshore heavy oil thermal recovery with rod pumping

Abstract The high-efficient development of heavy oil is difficult for offshore oil field. Based on the mature technology of onshore heavy oil thermal recovery, a new rod pumping technology of “heavy oil steam stimulation along with conventional sucker rod pumping system” is proposed. According to the structure space of aimed offshore platform, we designed one new kind of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure. The paper also studies the offshore heavy oil thermal recovery well safety technology, establishes a leakage model of wellhead sealing and a mechanical model of sealed rubber sleeve on downhole nonlinear large deformation. The study shows that a series of equipment for offshore rod pumping oil recovery and the key technology of well safety lay a solid foundation for carrying out rod pumping of offshore heavy oil thermal recovery

Study of a new hydraulic pumping unit based on the offshore platform

This article introduces a new technology about a rod pumping in the offshore platform according to the demand of offshore heavy oil thermal recovery and the production of stripper well, analyzes the research status of hydraulic pumping unit at home and abroad, and designs a new kind of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure to resolve the problem of space limitation. The article also describes the whole structure and the working principle of this pumping unit, determines the choice of stroke and rate of the pumping unit, and establishes mathematical models based on the polished rod loads. A new composite hydraulic cylinder with a special structure was designed by combining the hydraulic cylinder with the energy accumulator. This composite hydraulic cylinder is applied on land, and the model prototype runs smoothly, which indicates that the whole structure design of the pumping unit is reasonable and the control strategy is correct

Compared study of fucoidan from sea cucumber (Holothuria tubulosa) with different molecular weight on ameliorating β cell apoptosis

In this study, the effects of Holothuria tubulosa sea cucumber (Ht- FUC) with different molecular weight (Ht, Ht-1, Ht-2, Ht-3) on β cell apoptosis induced by high-fat-high-sucrose diet (HFD) in male C57BL/6J mice were investigated. After intervention with Ht-FUC (60 mg/kg body weight) for 16 weeks, results showed that different Ht-FUC could significantly decrease blood glucose and insulin levels, and reduce the burden of islet β cell secretion (P < 0.05). Notably, Ht-FUC significantly decreased serum free fatty acid (FFA) levels and lightened vacuolarization of islet. The results of qPCR and western blot showed that Ht-FUC suppressed PERK/CHOP and IRE1α/JNK pathways to inhibit ERS induced by FFA (P < 0.05). And then downregulated the expression of key genes in mitochondrial apoptosis pathway such as Bid, Bax, cytochrome c, caspase9 and caspase3 (P < 0.05), but didn’t affect Fas/FasL pathway, ultimately blocked the “FFA-endoplasmic reticulum stress (ERS)-apoptosis” cascade. All the results showed structure-activity relationship consistently and Ht-2 (196KDa) with short chain conformation played the best effect (P < 0.05)

Heat Transfer Performance of 3D-Printed Aluminium Flat-Plate Oscillating Heat Pipes for the Thermal Management of LEDs

With the rapid development of electronic technologies towards high integration, high power and miniaturization, thermal management has become an increasingly important issue to guarantee the reliability and service life of electronic devices. The oscillating heat pipe (OHP), which was governed by thermally excited oscillating motion, was considered as a promising technology to dissipate high-density heat and had excellent application prospects in many important industrial processes. A flat-plate OHP, however, was fabricated by traditional welding methods, which were difficult and inefficient, resulting in increasing the cost and wasting the production time. In this work, we adopted a new metal 3D printing technology to develop an aluminum flat-plate OHP, which made it facile to build complex inner channels with high-precision molding at one time. AlSi10Mg powders, as raw materials, were selectively melted and solidified to form the container of the flat-plate OHP. The sintered inner surface presented excellent wettability to the working fluid, which facilitated the evaporation of the working fluid. Acetone was chosen as the working fluid, and the filling ratios with a range of 40–70% were loaded into the flat-plate oscillating heat pipe to analyze its effect on heat transfer performance. It was found that the 3D-printed flat-plate OHP with a 60% filling ratio had a better heat transfer performance and a lower thermal resistance, and it was able to work properly in both vertical and horizontal operation modes. The 3D-printed flat-plate OHP had been successfully applied for the thermal management of high-power LEDs, and the results showed that the temperature of LEDs was maintained within 60 °C, and its service life was prolonged

Character study and elimination of turbidity of Acaudina molpadioides enzymatic hydrolysate

Sea cucumber is traditional restorative food in China, and the enzymatic hydrolysate of its body wall has been confirmed to have good physiological function. However, enzymatic hydrolysate prepared with low-value sea cucumber Acaudina molpadioides has significant turbidity phenomenon, which seriously affects hydrolysate quality, and is not beneficial for subsequent preparation of the efficacy composition of sea cucumber peptide and sulfated polysaccharide on the other hand. In this research, character study was carried out allusion to the Acaudina molpadioides enzymatic hydrolysate turbidity. And on this basis, method of elimination of Acaudina molpadioides enzymatic hydrolysate turbidity was established. The results showed that the turbidity material was composed of protein, lipid and ash. The surface potential was -46.3 mV, and the average particle size was 597 nm. The turbidity was mainly caused by protein and lipid. Protein was polymerized by hydrophobic interaction. The filtering of using AG-800# diatomite was the ideal method of elimination of Acaudina molpadioides enzymatic hydrolysate turbidity

Structural study of fucoidan from sea cucumber Acaudina molpadioides: a fucoidan containing novel tetrafucose repeating unit

Structure of fucoidan from sea cucumber Acaudina molpadioides (Am-FUC) was investigated in this study. Low molecular weight polysaccharide of Am-FUC (Am-LMW) was prepared by enzymatic degradation and assayed by nuclear magnetic resonance. According to the structure of Am-LMW, and referring to previously reported information of Am-FUC oligosaccharides, the structure of Am-FUC was elucidated as [-> 3-alpha-L-Fucp-1 -> 3-alpha-L-Fucp2,4(OSO3-)-1 -> 3-alpha-L-Fucp-1 -> 3-alpha-L-Fucp2(OSO3-)-1 ->](n). Compared to other investigated fucoidans, which also consist of tetrafucose repeating units with 1 3-linkages, Am-FUC contains a novel repeating unit distinctive in sulphation pattern. (C) 2013 Elsevier Ltd. All rights reserved