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- Author or Editor: D. Lu x
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Abstract
There is a thin layer of organic lubricant on commercial silver flake surfaces. This lubricant layer is a fatty acid salt formed between a fatty acid and silver flake surfaces. Thermal decomposition behavior of the silver flake lubricant is investigated in this study. The heat flow and mass loss of a silver flake are studied using differential scanning calorimetry (DSC) and thermogravimetry (TG), respectively. The silver flake is also oven heated to different isothermal temperatures (150,190, 250 and 300C) for one h. Then chemical nature of the lubricant of the heated silver flake sample are studied using diffuse reflectance infrared Fourier transfer spectroscopy (DRIFTS). Based on the results, a mechanism of thermal decomposition of the silver flake lubricant is proposed. It is found that decomposition of the lubricant - the fatty acid salt -includes the release of the fatty acid, formation of short chain acids by decomposition of hydrocarbon moiety of the fatty acid, and formation of alcohols through decarbonation of the short chain acids.
Abstract
There is a thin layer of organic lubricant on commercial silver (Ag) flakes that are widely used as the fillers in electrically conductive adhesives (ECAs). This lubricant layer highly affects the properties such as conductivity of the ECAs. Therefore, understanding the behavior of Ag flake lubricant layer is essential for developing high performance ECAs. This work is aimed at studying the chemical nature of the lubricant layer, interaction between the lubricant layer and Ag flakes, and thermal behavior of the lubricants during heating. A blank Ag powder is ball-milled into Ag flakes with five fatty acids that have different carbon–hydrogen chain length as lubricants. After lubrication, the Ag flakes are studied using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetry (TG), and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). It is found that (i) Ag flakes lubricated with fatty acids of different chain lengths have exothermic DSC peaks and mass losses at different temperatures, (ii) the lubricant layer on the lubricated Ag flake surfaces is a salt formed between the acid and Ag, and (iii) exothermic DSC peaks (in air) of a lubricated Ag flake is probably due to the oxidation of lubricant layer on the Ag flake surface.
Rice sheath blight, caused by Rhizoctonia solani, is the most serious disease in the southern rice producing regions of China. The use of resistant varieties is the most economic strategy to control the disease. In this paper, a seedling inoculation method was used to evaluate rice germplasm resources for resistance to sheath blight. A total of 363 rice varieties were evaluated with a set of R. solani isolates. The results indicated that the rice varieties generally lacked resistance to R. solani, and no highly resistant/immune (HR) variety was found. However, two varieties displayed clear resistance (R) and 37 showed moderate resistance (MR) to the fungus. Overall, hybrid rice varieties have better resistance than conventional rice varieties, and among hybrid rice varieties, those with the II-32A sterile line genetic background were the most resistant. The results also indicated significant interactions between rice varieties and pathogen isolates, suggesting that an understanding of local R. solani populations is needed when recommending varieties to local growers.
Analysis of the binding interaction of (−)-epigallocatechin-3-gallate (EGCG) and pepsin is important for understanding the inhibition of digestive enzymes by tea polyphenols. We studied the binding of EGCG to pepsin using fluorescence spectroscopy, Fourier transform infrared spectroscopy, isothermal titration calorimetry, and protein-ligand docking. We found that EGCG could inhibit pepsin activity. According to thermodynamic parameters, a negative ΔG indicated that the interaction between EGCG and pepsin was spontaneous, and the electrostatic force accompanied by hydrophobic binding forces may play major role in the binding. Data from multi-spectroscopy and docking studies suggest that EGCG could bind pepsin with a change in the native conformation of pepsin. Our results provide further understanding of the nature of the binding interactions between catechins and digestive enzymes.
Five giant embryo mutants, described as MH-gel, MH-ge2, MH-ge3, MH-ge4 and MH-ge5 , which were derived from the same indica rice cv . ‘Minghui 86’ and characterized by 2.0, 1.88, 2.08, 1.93 and 1.88 times enlarged embryo than that of wild type, were selected for the current study. The mutated giant embryos were controlled by a single recessive gene, and except mutated locus with MH-ge1 other four loci were allelic to each other and the previous reported locus ge in japonica rice cv . ‘Kinmaze’. No obvious differences in physicochemical properties such as apparent amylose content (AAC), alkali spreading value (ASV), gel consistency (GC), and starch paste viscosity were observed between giant embryo mutants and wild type. Significant increases in the contents of crude lipid (LC), crude protein (PC), Vitamin B1 (V B1 ), Vitamin B2 (V B2 ), Vitamin E (V E ), essential amino acids such as Arginine (Arg), Aspartic acid (Asp), Glutamic acid (Glu), Lysine (Lys), Methionine (Met), and mineral elements such as calcium (Ca), iron (Fe), potassium (K), phosphorus (P) and zinc (Zn) were detected in brown rice (BR) of giant embryo mutants. The amounts of gamma aminobutyric acid (GABA), an inhibitory neurotransmitter, were similar in the BR of giant embryo mutants and wild type, and more GABA content was observed in germinated brown rice (GBR) than BR. Significant enrichments were detected in the GBR of giant embryo mutants, basically corresponding to the enlarged embryo.
Abstract
Nuclear microprobe was used to measure single aerosol particles (SAPs) indoors from Shanghai. Every particle is characterized with its micro-PIXE spectrum, which can be considered as the fingerprint of the SAPs. The pattern recognition technique (PR) was applied to trace the SAPs back to their source. Results of five monitor homes at different locations in Shanghai show that most of the measured indoor aerosol particles are derived from soil dust, cement dust, vehicle exhaust, coal boilers and steel mill dust.
Abstract
Background and aims
Deficits in cognitive control represent a core feature of addiction. Internet Gaming Disorder (IGD) offers an ideal model to study the mechanisms underlying cognitive control deficits in addiction, eliminating the confounding effects of substance use. Studies have reported behavioral and neural deficits in reactive control in IGD, but it remains unclear whether individuals with IGD are compromised in proactive control or behavioral adjustment by learning from the changing contexts.
Methods
Here, fMRI data of 21 male young adults with IGD and 21 matched healthy controls (HC) were collected during a stop-signal task. We employed group independent component analysis to investigate group differences in temporally coherent, large-scale functional network activities during post-error slowing, the typical type of behavioral adjustments. We also employed a Bayesian belief model to quantify the trial-by-trial learning of the likelihood of stop signal – P(Stop) – a broader process underlying behavioral adjustment, and identified the alterations in functional network responses to P(Stop).
Results
The results showed diminished engagement of the fronto-parietal network during post-error slowing, and weaker activity in the ventral attention and anterior default mode network in response to P(Stop) in IGD relative to HC.
Discussion and conclusions
These results add to the literatures by suggesting deficits in updating and anticipating conflicts as well as in behavioral adjustment according to contextual information in individuals with IGD.
Global rice supplies have been found contaminated with unapproved varieties of genetically modified (GM) rice in recent years, which has led to product recalls in several of countries. Faster and more effective detection of GM contamination can prevent adulterated food, feed and seed from being consumed and grown, minimize the potential environmental, health or economic damage. In this study, a simple, reliable and cost-effective multiplex polymerase chain reaction (PCR) assay for identifying genetic modifications of TT51-1, Kemingdao1 (KMD1) and Kefeng6 (KF6) rice was developed by using the event-specific fragment. The limit of detection (LOD) for each event in the multiplex PCR is approximately 0.1%. Developed multiplex PCR assays can provide a rapid and simultaneous detection of GM rice.
Two new genera in the subfamily Teloschistoideae (Teloschistaceae, Teloschistales) are described: Hosseusiella S. Y. Kondr., L. Lőkös et A. Thell for the Caloplaca chilensis group including three South American species and Rehmanniella S. Y. Kondr. et J.-S. Hur for the new species, R. wirthii S. Y. Kondr. from South Africa. The new genera are supported by a three-gene phylogeny based on ITS1/ITS2 nrDNA, 28S nrLSU, and 12S mtSSU sequences. The new taxonomic position of Elixjohnia ovis-atra in the subfamily Teloschistoideae is discussed. The two new species Hosseusiella gallowayiana and Rehmanniella wirthii are described, illustrated and compared with closely related taxa. Hosseusiella gallowayiana is recorded for the first time as the host for the lichenicolous fungus Arthonia tetraspora S. Y. Kondr. A key to the species of Hosseusiella is included, as well as new information of the related genus Follmannia. The following new combinations are proposed: Hosseusiella chilensis (Kärnefelt, S. Y. Kondr., Frödén et Arup) S. Y. Kondr., L. Lőkös, Kärnefelt et A. Thell, Hosseusiella pergracilis (Zahlbr.) S. Y. Kondr., L. Lőkös, Kärnefelt et A. Thell and Elixjohnia ovis-atra (Søchting, Søgaard et Sancho) S. Y. Kondr.