Quantitative Analysis of Phenolic Acids and Flavonoids in Cuscuta chinensis Lam. by Synchronous Ultrasonic-Assisted Extraction with Response Surface Methodology

An effective ultrasonic-assisted extraction method for the separation of phenolic acids and flavonoids in Cuscuta chinensis Lam. was conducted by combining uniform design (UD) coupled with response surface methodology (RSM) and orthogonal design (OD) experiment. A sensitive and selective high-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (HPLC-ESI-MS/MS) method was applied to quantify the sixteen active ingredients (chlorogenic acid, cryptochlorogenic acid, neochlorogenic acid, isochlorogenic acid A, isochlorogenic acid B, isochlorogenic acid C, caffeic acid, hyperin, isoquercitrin, quercetin, campherol, p-coumaric acid, isorhamnetin, rutin, astragalin, and apigenin). The extraction method was optimized with respect to concentration of extraction solvent, extraction time, and ratio of liquid to solid as a consequence of getting a high sensitive and feasible method for simultaneous determination of contents of multiple components and evaluation of quality control of Cuscuta chinensis Lam. from different origins. It was also considered useful and valuable in the further study for quality control of Cuscuta chinensis Lam

Isothermal phase transformation characteristics and mechanical properties of ultra-high strength β titanium alloy

Near β titanium alloy is widely used in automotive and aerospace industries due to their high strength-to-weight ratio and high corrosion resistance. The near β titanium alloy can precipitate ω phase and α phase after solution and ageing treatment, the strength of which can be remarkably increased, usually at the expense of ductility. It is one of the most important structural components of load-bearing that usually as aircraft skin, shell plating, main frame, linker and special fastener. The alloy used in this paper is a self-developed Ti-Al-V-Mo-Cr-Zr-Fe-Nb ultra-high-strength β titanium alloy, which is a typical near β titanium alloy. The characteristic of isothermal phase transformation of near β titanium alloys is diversity and complexity, which is sensitive to temperature and directly affects the mechanical properties after ageing. In this paper, the microstructural evolution and mechanical properties of a Ti-Al-V-Mo-Cr-Zr-Fe-Nb ultra-high strength β titanium alloy after isothermal treatment were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM) and micro-hardness tester. The results show that only the isothermal ω precipitates are formed during ageing at 300℃, and the size of isothermal ω phases increase with the ageing time. The isothermal ω precipitates are first precipitated during ageing at 400℃. With the extension of the ageing time, the α phase nucleation occurs near the ω/β interface. No α precipitates are obtained in the alloy aged at 500℃, and needle-like α precipitates are directly precipitated from the β matrix, which is evenly distributed in the β matrix in a "V" shape. Tensile test shows that the tensile strength of the alloy is 1716.1 MPa and the elongation is 2% after ageing at 400℃ for 12 h. The tensile strength of the alloy is 1439.8 MPa and the elongation is 9.84% after ageing at 500℃ for 12 h, and has a good combination of strength and toughness

Microstructure and mechanical properties of a Monel K-500 alloy fabricated by directed energy deposition

Directed energy deposition (DED) is a mainstream metal additive manufacturing technique that can fabricate near-net-shape components and repair damaged parts with a high build rate. Monel K-500 is a Ni-based alloy widely used for marine and offshore applications because of its excellent corrosion resistance and good combination of strength and ductility. In this study, laser-assisted DED (L-DED) was used to print Monel K-500 parts from powder. The key process parameters, including the laser power and scanning speed, were optimized to obtain single beads with desirable geometry and blocks with nearly full density (≥99%). The block samples printed by L-DED exhibit ∼20% higher ultimate tensile strength and ∼60% higher elongation to failure than their conventional cast counterparts. From the microstructure examination, it is found that the parts printed with a low laser power have fine grains and an alternating equiaxed/columnar-grain sandwich structure with high tensile strength. In contrast, those printed with a high laser power have coarse columnar grains with a strong texture but low tensile strength. The mechanism accounting for the grain structure evolution was studied by computational fluid dynamics and cellular automata simulations. The anisotropy in mechanical properties is mainly attributed to the difference in grain boundary strengthening effects. Moreover, the increase in hardness and tensile strength of the heat-treated samples is attributed to the precipitation hardening effect. This work exemplifies how the process parameters can be tuned to control the grain texture to achieve superior mechanical properties for parts of Monel K-500 and other metals printed by L-DED.Economic Development Board (EDB)National Research Foundation (NRF)This work was supported by the Economic Development Board, Singapore and DNV Singapore Pte Ltd through the Industrial Post-graduate Programme with Nanyang Technological University, Singapore and by the National Research Foundation, Singapore under its Medium-Sized Centre funding scheme through the Marine and Offshore Program

Dual-functional ionic porous organic framework for palladium scavenging and heterogeneous catalysis

Porous organic frameworks (POFs) with predesigned structures and tunable porosities have been widely studied in adsorption and heterogeneous catalysis. Introducing ionic structure into the framework endows POFs with new functionalities that may extend their applications. Here, we report new applications for a guanidinium-based ionic POF (IPOF-Cl) in palladium scavenging and heterogeneous catalysis. Due to the ionic framework and the porous structure, the IPOF-Cl displays fast adsorption kinetics and high adsorption capacities (up to 754 mg g−1) of Na2PdCl4 in aqueous solutions via a chemisorption (ion exchange) process. Significantly, it shows excellent scavenging activity towards trace amount of [PdCl4]2− in aqueous solution. More importantly, the loaded [PdCl4]2− species on the IPOF substrate are further reduced into ultrafine Pd nanoparticles with size of ∼2–5 nm. The obtained IPOF-Pd(0) nanocomposite containing uniformly distributed Pd nanoparticles and hierarchical porous structure demonstrates high activity in catalyzing a range of Suzuki coupling reactions. This study provides new routes for the development of ionic porous organic materials for applications in metal scavenging and catalysis

Genome-wide identification and characterization of long non-coding RNAs during postnatal development of rabbit adipose tissue

Abstract Background The rabbit is widely used as an important experimental model for biomedical research, and shows low adipose tissue deposition during growth. Long non-coding RNAs (lncRNAs) are associated with adipose growth, but little is known about the function of lncRNAs in the rabbit adipose tissue. Methods Deep RNA-sequencing and comprehensive bioinformatics analyses were used to characterize the lncRNAs of rabbit visceral adipose tissue (VAT) at 35, 85 and 120 days after birth. Differentially expressed (DE) lncRNAs were identified at the three growth stages by DESeq. The cis and trans prediction ways predicted the target genes of the DE lncRNAs. To explore the function of lncRNAs, Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed on the candidate genes. Results A total of 991,157,544 clean reads were generated after RNA-Seq of the three growth stages, of which, 30,353 and 107 differentially expressed (DE) lncRNAs were identified. Compared to the protein-coding transcripts, the rabbit lncRNAs shared some characteristics such as shorter length and fewer exons. Cis and trans target gene prediction revealed, 43 and 64 DE lncRNAs respectively, corresponding to 72 and 20 protein-coding genes. GO enrichment and KEGG pathway analyses revealed that the candidate DE lncRNA target genes were involved in oxidative phosphorylation, glyoxylate and dicarboxylate metabolism, and other adipose growth-related pathways. Six DE lncRNAs were randomly selected and validated by q-PCR. Conclusions This study is the first to profile the potentially functional lncRNAs in the adipose tissue growth in rabbits, and contributes to our understanding of mammalian adipogenesis

A high-performance broadband terahertz absorber based on sawtooth-shape doped-silicon

Perfect absorbers with broadband absorption of terahertz (THz) radiation are promising for applications in imaging and detection to enhance the contrast and sensitivity, as well as to provide concealment. Different from previous two-dimensional structures, here we put forward a new type of THz absorber based on sawtooth-shape doped-silicon with near-unit absorption across a broad spectral range. Absorbance over 99% is observed numerically from 1.2 to 3 THz by optimizing the geometric parameters of the sawtooth structure. Our absorbers can operate over a wide range of incident angle and are polarization insensitive. The underlying mechanisms due to the combination of an air-cavity mode and mode-matching resonance on the air-sawtooth interface are analyzed in terms of the field patterns and electromagnetic power loss features

Table3_Eight weeks of dry dynamic breath-hold training results in larger spleen volume but does not increase haemoglobin concentration.XLSX

Purpose: It has previously been reported that repeated exposure to hypoxia increases spleen size and haemoglobin (HGB) level and recent reports on the effect apnoea has on spleen size and haematological parameters are contradictory. Therefore, this study aims to evaluate the effect apnoea training has on spleen size and haematological parameters.Methods: The breath-holding (BH) group was comprised of 12 local student-athletes with no BH exercise experience who performed BH jogging and BH jumping rope dynamic apnoea protocols, five times weekly for 8 weeks. The BH event duration was progressively increased as the apnoea tolerance of the athletes improved (20 to 35 s). The same training task was performed by the control group (n = 10) without BH. Spleen sizes were measured with an ultrasound system and a complete blood cell analysis was performed on the median cubital venous blood.Results: Spleen volume in the BH group increased from 109 ± 13 ml to 136 ± 13 ml (p Conclusion: Eight weeks of dry dynamic apnoea training increased spleen size and decreased the number of circulating bulky platelets in the athletes who were assessed in this study. However, the baseline RBC counts and HGB levels of the athletes were not altered by the training programme.</p