The relationship between sample temperature and the plasma spectrum is of great significance to the water quality monitoring using the laser-induced breakdown spectroscopy (LIBS). In this work, we ...study the effect of temperature variation on the plasma spectrum in CaCl
2
solution for on-line analysis using the LIBS. The effects of sample solution temperature from 25 to 80 °C on the emission spectral intensity, the signal-to-background ratio (SBR) and quantitative analysis of the laser-induced plasma are studied. When the temperature rises from 25 to 70 °C, the emission spectral intensity and the SBR of the laser plasma increase or get enhanced with the increase of temperature. However, when the temperature further increases from 70 to 80 °C, the spectral intensity and the SBR begin to decrease. The enhancement rate reaches the maximum at 70 °C. In quantitative analysis, the fitting curve and the root mean square errors (RMSE) increase with the increase of the sample temperature. The relevant parameters peak at 70 °C. At this optimal temperature, the correlation coefficients of Ca II 393.366 and Ca II 396.847 nm are found to be 0.9988 and 0.9953, respectively, with the RMSE decreased to 0.16 and 0.27%, respectively, and the lowest detection limits are 27.99 and 28.10 μg ml
−1
, respectively. This study demonstrates that the preheating to the samples can effectively improve the LIBS ability for on-line analysis and detection of water quality.
Bamboo fiber has attracted a lot of interest due to its high specific strength and renewability. Unidirectional long bamboo fiber reinforcing is essential to fully realize its strength. The ...reinforcing efficiency can also be affected by the physical and chemical structure of bamboo fibers. Therefore, this study reviews the cell wall structure of the bamboo fiber. The alternately arranged structure with thin and thick layers contributes substantially to the mechanical strength of the bamboo fiber. In addition, this study evaluates the mechanical properties, water absorption, and flame retardancy of polymeric and cementitious composites reinforced with long bamboo fibers. Thermoset polymer-based bamboo fiber composites typically show higher mechanical strength than thermoplastic-based fiber composites. Chemical treatment and flame retardant can significantly enhance the hydrophobicity and flame retardancy of fiber composites, respectively. Because of its superior interface performance, the short bamboo fiber has a greater reinforcing effect in cement mortar than in concrete. This study can serve as a reference for further investigations on bamboo fiber/bundle reinforced composites and promote their applications.
Luminescent metal-organic layers (LMOLs) that can effectively improve fluorescence quantum yield and sensing performance are rarely reported. Herein, a novel tetracarboxyl-substituted ...tetraphenylethene (TPE) ligand 1,1,2,2-tetrakis(3-carboxyphenyl)phenylethylene (H4T3CPPE) with significant aggregation-induced emission (AIE) effect was synthesized. A 2D luminescent cage-based metal-organic framework Zn2(T3CPPE)(H2O)2 (complex 1) was prepared by the reaction of H4T3CPPE with zinc salt, and then highly luminescent TPE-based LMOL 1 was obtained from complex 1 by ultrasonication-induced exfoliation method, which was used to detect nitrofuran antibiotics (NFT and NFZ) in aqueous solution selectively and sensitively. Compared to bulk luminescent metal-organic framework complex 1, the LMOL 1 delaminated in isopropanol has an fluorescence quantum yield enhancement, reaching 99% in LMOL 1 from 62.9% in complex 1 and exhibits higher fluorescence quenching effect towards nitrofuran antibiotics with lower limit of detections (LODs). Compared with other antibiotics, at a fluorescent titration concentration of 50.5 μM, nitrofuranone and nitrofurantoin can quench the fluorescence of LMOL 1 more effectively with the quenching efficiency of 84.9% and 87.7%, respectively, indicating it can function as an excellent luminescence sensor to detect these antibiotics.
Display omitted Synopsis: A tetraphenylethene-based luminescent metal-organic layer with high fluorescence quantum yield sensitive enhancement for detection of antibiotics in aqueous medium.
•A two-dimensional cage-based luminescent metal-organic framework with high fluorescence quantum yield was synthesized.•Luminescent metal-organic layer (LMOL) was obtained through exfoliation method with fluorescence quantum yield enhancement.•Luminescent metal-organic layer (LMOL) showed sensitive enhancement detection of antibiotics in aqueous medium.
We recently identified a novel plasmid-mediated resistance-nodulation-division (RND)-type efflux pump gene cluster,
, in
that conferred resistance to multiple antimicrobials, including tigecycline. ...While homologs of
were found encoded in many other bacterial species in GenBank, their functions and transfer mechanisms remain unknown. This study identified another mobile gene cluster,
, co-occurring on both a plasmid (pHNNC189-2) and the chromosome of a clinical
isolate, strain NC189, producing KPC-2, NDM-1, and RmtC.
shares high similarity at the nucleotide level with
, with 98.02%, 96.75%, and 99.93% identities to
,
, and
, respectively. Phylogenetic analysis revealed that
may have originated from the chromosome of a
species. The expression of
in an
strain resulted in an 8-fold increase in the tigecycline MIC and decreased susceptibility to other antimicrobials. Genetic context analyses demonstrated that
, together with the adjacent hypothetical site-specific integrase genes, was possibly captured and mobilized by a XerD-like tyrosine recombinase system, forming a putative transposition unit (
-like-
-like-
Δ
-
-like-
-like-
IS
Δ
), which was inserted into
like genes in both the NC189 plasmid pHNNC189-2 and the chromosome. Since
and
could confer multidrug resistance, the spread of these gene clusters, associated with the new recombinase system, calls for more attention.
Alzheimer’s disease (AD) is the most common neurodegenerative disease, characterized by progressive cognitive impairment and memory loss. So far, the pathogenesis of AD has not been fully understood. ...Research have shown that endoplasmic reticulum (ER) stress and unfolded protein response (UPR) participate in the occurrence and development of AD. Furthermore, various studies, both
in vivo
and
in vitro
, have shown that targeting ER stress and ER stress-mediated apoptosis contribute to the recovery of AD. Thus, targeting ER stress and ER stress-mediated apoptosis may be effective for treating AD. In this review, the molecular mechanism of ER stress and ER stress-mediated apoptosis, as well as the therapeutic effects of some natural compounds and small molecule inhibitors targeting ER stress and ER stress-mediated apoptosis in AD will be introduced.
A vortex-assisted dispersive liquid–liquid microextraction (VA-DLLME) procedure using hydrophobic deep eutectic solvent–based ferrofluid (HDES-FF) as an extractant was established. The developed ...sample preparation method coupled with high-performance liquid chromatography–diode array detector (HPLC–DAD) was applied to the pretreatment and determination of myclobutanil (MYC) in fruit juice. Hydrophobic deep eutectic solvent, synthesized by n-decanoic acid and
dl
-menthol, was as a carrier and combined with magnetic nanoparticles (Fe
3
O
4
@OA) to form HDES-FF as an extractant with high extraction capacity. The synthesized materials were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). Parameters affecting extraction efficiency were optimized using single-factor experiments and Box-Behnken design via response surface methodology (BBD-RSM). Parallel tests were performed three times under the optimal conditions predicted by the model, yielding an actual mean recovery of 94.77% with RSD of 2.7% (
n
= 3) and an enrichment factor of 41.8 ± 0.98 (mean value ± SD,
n
= 3). Under the optimal conditions, the linear range was 1.0–100.0 µg·mL
−1
; the limit of detection (LOD) and limit of quantification (LOQ) were 0.25 and 0.80 µg·mL
−1
, respectively. The average spiked recoveries in the samples ranged from 98.2 to 100.5% with intra-day relative standard deviations (RSDs) of 1.2–3.5% (
n
= 3) and inter-day RSDs of 1.1–3.8% (
n
= 3). Finally, the method was successfully applied to the determination of MYC antimicrobial agent in different fruit juice samples. The proposed HDES-FF-VA-DLLME/HPLC–DAD method was verified to widely apply to the extraction of triazole fungicides.
Graphical Abstract
Monoterpenoid indole alkaloids (MIAs) represent a major class of active ingredients from the plants of the genus Gelsemium. Gelsemium MIAs with diverse chemical structures can be divided into six ...categories: gelsedine-, gelsemine-, humantenine-, koumine-, sarpagine- and yohimbane-type. Additionally, gelsemium MIAs exert a wide range of bioactivities, including anti-tumour, immunosuppression, anti-anxiety, analgesia, and so on. Owing to their fascinating structures and potent pharmaceutical properties, these gelsemium MIAs arouse significant organic chemists' interest to design state-of-the-art synthetic strategies for their total synthesis. In this review, we comprehensively summarised recently reported novel gelsemium MIAs, potential pharmacological activities of some active molecules, and total synthetic strategies covering the period from 2013 to 2022. It is expected that this study may open the window to timely illuminate and guide further study and development of gelsemium MIAs and their derivatives in clinical practice.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
This study used environmentally friendly nano-xylan to enhance the drug loading and preservative performance (especially against white-rot fungi) of pine wood (
), determine the best pretreatment, ...nano-xylan modification process, and analyze the antibacterial mechanism of nano-xylan. High-temperature, high-pressure steam pretreatment-assisted vacuum impregnation was applied to enhance the nano-xylan loading. The nano-xylan loading generally increased upon increasing the steam pressure and temperature, heat-treatment time, vacuum degree, and vacuum time. The optimal loading of 14.83% was achieved at a steam pressure and temperature of 0.8 MPa and 170 °C, heat treatment time of 50 min, vacuum degree of 0.08 MPa, and vacuum impregnation time of 50 min. Modification with nano-xylan prohibited the formation of hyphae clusters inside the wood cells. The degradation of integrity and mechanical performance were improved. Compared with the untreated sample, the mass loss rate of the sample treated with 10% nano-xylan decreased from 38 to 22%. The treatment with high-temperature, high-pressure steam significantly enhanced the crystallinity of wood.
Staphylococcus aureus is a major causative microorganism in community- and healthcare-acquired pneumonia. CD5L is an important protein in the control of immune homeostasis. In this study, we found ...that patients with S. aureus pneumonia displayed increased levels of circulating CD5L. Likewise, mice with S. aureus pneumonia had elevated CD5L levels in the lungs. Anti-CD5L antibody protected mice from lethal pneumonia induced by methicillin-resistant S. aureus. The survival benefit obtained with antibody against CD5L was associated with an improvement of bacterial clearance and a reduction of pulmonary inflammatory cytokines and chemokines. Conversely, co-injection of recombinant CD5L and S. aureus markedly increased the lethality of S. aureus pneumonia. These findings suggest that CD5L contributed to the immunopathology of S. aureus pneumonia.
•CD5L levels are significantly elevated in clinical and experimental S. aureus pneumonia.•Blockade of the CD5L activity could protect mice from lethal pneumonia induced by methicillin-resistant S. aureus.•CD5L may play a role in the immunopathology of S. aureus pneumonia.
•A biosurfactant-assisted mechanical amorphous dispersion extraction was developed.•Salvia miltiorrhiza samples were mechanically ground with sodium chenodeoxycholate.•Simultaneous extraction of ...hydrophilic and hydrophobic analytes was achieved.•The method obtained high extraction efficiency under organic solvent-free conditions.
A biosurfactant-assisted mechanical amorphous dispersion extraction (BA-MADE) procedure was established for the simultaneous capture of hydrophilic phenolic acids and hydrophobic tanshinones from Salvia miltiorrhiza. Single-factor experiments and the response surface methodology were used to optimize and analyze the crucial parameters for the method, such as the type and amount of amorphous-dispersion extractants, grinding time, extraction time and solid-to-liquid ratio. The optimized parameter values for the BA-MADE process were 407.02 mg of sodium chenodeoxycholate, a grinding time of 4.87 min, an extraction time of 4.92 min, and a solid-to-liquid ratio of 0.5:10 g/mL. The calibration curves of danshensu, rosmarinic acid, lithospermic acid, salvianolic acid B, salvianolic acid A, dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone II A exhibited good linearity in the range of 1–500 μg/mL (R2 ≥ 0.9990). The limits of detection of nine analytes ranged from 5.46 to 130 ng/mL, the relative standard deviations (RSDs) of intraday and interday precision were less than 1.95 and 3.56%, respectively, and the recoveries of the real sample were in the range of 85–113%, with RSD% below 3.21%. The BA-MADE method was compared with previously reported methods, such as heating reflux extraction, ultrasonic extraction and microwave-assisted micellar extraction, and the results demonstrated that the developed method has significant advantages in the simultaneous extraction of hydrophilic and hydrophobic active components from Salvia miltiorrhiza.
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