555 research outputs found
Optimal extraction parameters of Theabrownin from Sichuan Dark Tea
Background: Sichuan Dark Tea is a popular beverage with hypolipidemic and lifting greasy properties in the minority neighborhoods of Sichuan and Tibet regions. The theabrownin, an important pigment of dark tea, has been proven for the role of the hypolipidemic property in Sichuan Dark Tea. The objective of the study investigated the extraction process of theabrownin.Materials and Methods: Theabrownin was extracted from Sichuan Dark Tea with water and organic solvents. The quadratic regression orthogonally rotational combinational design experiment was performed to obtain the optimal extraction parameters.Results: The extraction yield of theabrownin was significantly influenced by both water extraction temperature and solid-liquid ratio, and the contribution of these factors on theabrownin yield was as follows: water temperature﹥solid-liquid ratio﹥organic solvent temperature. Moreover, the polynomial regression model established could predict the experimental value accurately.Conclusion: The optimum extraction process of theabrownin from Sichuan Dark Tea was established, which water temperature at 65.69-77.88℃, organic solvent temperature at 13.65-17.48℃ and a solid liquid ratio of 1:43.58-1:50.75(g/mL).Keywords: theabrownin; extraction; optimization; Sichuan Dark TeaAbbreviations list: SDT: Sichuan Dark Tea; TB: Theabrowni
Large-deviation analysis for counting statistics in mesoscopic transports
We present an efficient approach, based on a number-conditioned master
equation, for large-deviation analysis in mesoscopic transports. Beyond the
conventional full-counting-statistics study, the large-deviation approach
encodes complete information of both the typical trajectories and the rare
ones, in terms of revealing a continuous change of the dynamical phase in
trajectory space. The approach is illustrated with two examples: (i) transport
through a single quantum dot, where we reveal the inhomogeneous distribution of
trajectories in general case and find a particular scale invariance point in
trajectory statistics; and (ii) transport through a double dots, where we find
a dynamical phase transition between two distinct phases induced by the Coulomb
correlation and quantum interference.Comment: 8 pages, 3 figure
Frajunolides L–O, Four New 8-Hydroxybriarane Diterpenoids from the Gorgonian Junceella fragilis
Four new 8-hydroxybriarane diterpenoids, frajunolides L–O (1–4), were isolated from the Taiwanese gorgonian Junceella fragilis. The structures of compounds 1–4 were elucidated based on spectroscopic analysis, especially 2D NMR (1H-1H COSY, HSQC, HMBC and NOESY) and HRMS. Compounds 1 and 4 showed weak anti-inflammatory activity as tested by superoxide anion generation and elastase release by human neutrophil in response to fMLP/CB. Compound 3 showed selective inhibition on elastase release in vitro
A 1-hydroxy-2,4-diformylnaphthalene-based fluorescent probe and its detection of sulfites/bisulfite
A novel 1-hydroxy-2,4-diformylnaphthalene-based fluorescent probe L was synthesized by a Knoevenagel reaction and exhibited excellent sensitivity and selectivity towards sulfite ions (SO32−) and bisulfite ions (HSO3−). The detection limits of the probe L were 0.24 μM using UV-Vis spectroscopy and 9.93 nM using fluorescence spectroscopy, respectively. Furthermore, the fluorescent probe L could be utilized for detection in real water samples with satisfactory recoveries in the range 99.20%~104.30% in lake water and 100.00%~104.80% in tap water by UV-Vis absorption spectrometry, and in the range 100.50%~108.60% in lake water and 102.70%~103.80% in tap water by fluorescence spectrophotometry
OPTIMAL EXTRACTION PARAMETERS OF THEABROWNIN FROM SICHUAN DARK TEA
Background: Sichuan Dark Tea is a popular beverage with hypolipidemic and lifting greasy properties in the minority
neighborhoods of Sichuan and Tibet regions. The theabrownin, an important pigment of dark tea, has been proven for the role of the
hypolipidemic property in Sichuan Dark Tea. The objective of the study investigated the extraction process of theabrownin.
Materials and Methods: Theabrownin was extracted from Sichuan Dark Tea with water and organic solvents. The quadratic
regression orthogonally rotational combinational design experiment was performed to obtain the optimal extraction parameters.
Results: The extraction yield of theabrownin was significantly influenced by both water extraction temperature and solid-liquid ratio,
and the contribution of these factors on theabrownin yield was as follows: water temperature﹥solid-liquid ratio﹥organic solvent
temperature. Moreover, the polynomial regression model established could predict the experimental value accurately.
Conclusion: The optimum extraction process of theabrownin from Sichuan Dark Tea was established, which water temperature at
65.69-77.88℃, organic solvent temperature at 13.65-17.48℃ and a solid-liquid ratio of 1:43.58-1:50.75(g/mL)
Experimental and Theoretical Investigation of Multispecies Oral Biofilm Resistance to Chlorhexidine Treatment
We investigate recovery of multispecies oral biofilms following chlorhexidine gluconate (CHX) and CHX with surface modifiers (CHX-Plus) treatment. Specifically, we examine the percentage of viable bacteria in the biofilms following their exposure to CHX and CHX-Plus for 1, 3, and 10 minutes, respectively. Before antimicrobial treatment, the biofilms are allowed to grow for three weeks. We find that (a). CHX-Plus kills bacteria in biofilms more effectively than the regular 2% CHX does, (b). cell continues to be killed for up to one week after exposure to the CHX solutions, (c). the biofilms start to recover after two weeks, the percentage of the viable bacteria recovers in the 1 and 3 minutes treatment groups but not in the 10 minutes treatment group after five weeks, and the biofilms fully return to the pretreatment levels after eight weeks. To understand the mechanism, a mathematical model for multiple bacterial phenotypes is developed, adopting the notion that bacterial persisters exist in the biofilms together with regulatory quorum sensing molecules and growth factor proteins. The model reveals the crucial role played by the persisters, quorum sensing molecules, and growth factors in biofilm recovery, accurately predicting the viable bacterial population after CHX treatment.Fundación Obra Social de La CaixaFundación CanadáFundación Ramón Areces (Postdoctoral Scholarship
TMRT observations of 26 pulsars at 8.6 GHz
Integrated pulse profiles at 8.6~GHz obtained with the Shanghai Tian Ma Radio
Telescope (TMRT) are presented for a sample of 26 pulsars. Mean flux densities
and pulse width parameters of these pulsars are estimated. For eleven pulsars
these are the first high-frequency observations and for a further four, our
observations have a better signal-to-noise ratio than previous observations.
For one (PSR J0742-2822) the 8.6~GHz profiles differs from previously observed
profiles. A comparison of 19 profiles with those at other frequencies shows
that in nine cases the separation between the outmost leading and trailing
components decreases with frequency, roughly in agreement with
radius-to-frequency mapping, whereas in the other ten the separation is nearly
constant. Different spectral indices of profile components lead to the
variation of integrated pulse profile shapes with frequency. In seven pulsars
with multi-component profiles, the spectral indices of the central components
are steeper than those of the outer components. For the 12 pulsars with
multi-component profiles in the high-frequency sample, we estimate the core
width using gaussian fitting and discuss the width-period relationship.Comment: 33 pages, 49 figures, 5 Tables; accepted by Ap
The bricolage mode of emergency medical teams in China: deficient and in urgent need of transformation—A qualitative study
IntroductionEmergency medical rescue plays a vital role in alleviating the harm of all kinds of emergencies to people's physical and mental health and life safety. The current emergency medical teams (EMTs) formation model is not unified. We focused on the disadvantages of the bricolage mode of China EMTs and put forward empirical-based countermeasures to improve the emergency management ability of EMTs.MethodsFrom March to September 2022, 23 leaders of EMTs in North China (Tianjin) were selected by objective sampling method to conduct one-to-half structured in-depth interviews. Nvivo12.0 software was used for three-level coding. The disadvantages of the bricolage model of EMT were analyzed.ResultsBased on the three-level coding, 150 initial concepts, 36 sub-coding, 17 main coding, six categories, and two core categories were sorted out. Management structure, internal stability, and support are recognized as the crucial elements armed with the EMTs.DiscussionThe bricolage EMTs have disadvantages such as a chaotic management structure, weak internal stability, and inadequate support. It is necessary to construct full-time EMTs that incorporate a standardized personnel admission mechanism, full-time training and exercise mechanism, diversified incentive mechanism, and multi-agent cooperation mechanism, etc
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