•A nonlinear dynamic problem of the sandwich structure under impact is investigated.•Non-uniform stiffener designing is considered.•Thermoelastic behavior of the doubly curved plate is discussed.
In ...this paper, dynamic analysis of a stiffened doubly curved sandwich composite plate with a functionally graded material (FGM) core and two isotropic layers in thermal environment is presented. Based on von Kármán non-linear strain–displacement relationships and classical plate theory, a list of non-linear dynamic equilibrium equations for stiffened FGM sandwich doubly curved plates under impact in thermal field are established by using the Hamilton’s variation principle, then combining with boundary and initial conditions, the whole problem is solved by adopting the finite difference method, Newmark method and iterative method synthetically. To verify the accuracy of the present work, comparisons are made with previously published results. The detailed studies about the influence of prime parameters like initial impact velocity, material property, temperature boundary condition, geometry parameters of doubly curved plate and non-uniform stiffeners on nonlinear dynamic response of the structure subject to impact with thermal effect are carried out.
Metformin has been widely used as an oral drug for the treatment of diabetes mellitus. However, its consumption can be influenced by many economic and social factors. In this study, we investigated ...the spatial consumption pattern of metformin in China through wastewater-based epidemiology (WBE) approach. Influent wastewater samples were collected from 21 wastewater treatment plants (WWTPs) in 19 cities of the northeast China. A method using solid-phase extraction combined with N-Methyl-bis (trifluoroacetamide) derivatization for GC-MS detection was applied for metformin analysis. In 21 days, metformin showed high stability in wastewater at 24 °C and −20 °C. The mean concentrations of metformin in all WWTPs ranged from 2.42 μg L−1 to 53.6 μg L−1. The consumption of metformin was 0.66–15.6 mg d−1 capita−1 with the mean value of 5.54 ± 4.28 mg d−1 capita−1. The prevalence of metformin ranged from 0.09% to 2.10% with an average of 0.74%. Both the consumption and prevalence of metformin displays significant spatial variations in northeast China. A statistical correlation analysis indicated that the consumption of metformin increases with the decrease of per capita disposable income of urban residents. To further predict the use of metformin in China, we developed a regress model and depicted a consumption map. The annual consumption of urban residents in Chinese provinces range from 1085-63,828 kg yr−1 with mean value of 25,347 kg yr−1, which would provide a certain reference value for public health care and diabetes control.
•Metformin use in China was the first time evaluated by wastewater-based epidemiology.•Significant spatial variation was shown in the northeast China.•Consumption of metformin exhibited increase with the decreasing per capita income.•A regress model was provided for the forecast of metformin consumption in China.
BACKGROUNDThe detection of 25-hydroxyvitamin D (25OHD) from dried blood spots (DBS) has been widely studied. However, the existing pretreatment methods suffer from limitations in terms of throughput ...(usually exceeding 2 h), complexity (involving liquid-liquid extraction or solid-phase extraction), and contamination (including multiple steps of organic solvent evaporation).RESULTSWe first released 25OHD from DBS samples by 50% acetonitrile solution through ultrasonication. Subsequently, the cold-induced phase separation technique was introduced for in-situ concentration and purification. Afterward, the PTAD derivatization of 25OHD was performed directly, profiting from the high acetonitrile content in the concentrated solution. In the end, the resulting solution was submitted to LC-MS/MS for quantification. The established LC-MS/MS methodology possessed favorable analytical performance, possessing lower limit of quantification of 1 ng/mL pointing to plasma, accuracy of 86.8-110.1% and imprecision of 5.4-16.8%. Method comparison with plasma samples demonstrated that over 93% of the detections met the acceptance limit for cross-validation of ±20%.SIGNIFICANCE AND NOVELTYThe novel sample preparation can be finished within 15 min and eliminated the traditional steps of extraction and organic solvent evaporation. Based on this high-throughput, reliable and applicable LC-MS/MS method, the detection of 25OHD in DBS samples can be better achieved for clinical patients and researchers with relevant demands.
A new kind of environmentally friendly filter paper based on ultralong hydroxyapatite nanowires (HAPNWs) and cellulose fibers (CFs) with excellent filtration and adsorption properties has been ...developed for the application in high-performance water purification. The use of polyamidoamine-epichlorohydrin (PAE) resin increases the wet mechanical strength of the as-prepared HAPNW/CF filter paper. The addition of CFs enhances the mechanical strength of the HAPNW/CF filter paper. Owing to the porous structure and superhydrophilicity of the as-prepared HAPNW/CF filter paper, the pure water flux is as high as 287.28 L m–2 h–1 bar–1 under cross-flow conditions, which is about 3200 times higher than that of the cellulose fiber paper with addition of PAE. More importantly, the as-prepared HAPNW/CF filter paper shows superior performance in the removal of TiO2 nanoparticles (>98.61%) and bacteria (up to 100%) in water by the size exclusion and blocking effect. In addition, the HAPNW/CF filter paper also exhibits high adsorption capacities for methyl blue (273.97 mg g–1) and Pb2+ ions (508.16 mg g–1). The adsorption mechanism of the HAPNW/CF filter paper is investigated. The as-prepared environmentally friendly HAPNW/CF filter paper with both excellent filtration and adsorption properties has promising application in high-performance water purification to tackle the worldwide water scarcity problem.
Adsorption of three aromatic organic compounds (AOCs) by four types of carbonaceous adsorbents a granular activated carbon (HD4000), an activated carbon fiber (ACF10), two single-walled carbon ...nanotubes (SWNT, SWNT-HT), and a multiwalled carbon nanotube (MWNT) with different structural characteristics but similar surface polarities was examined in aqueous solutions. Isotherm results demonstrated the importance of molecular sieving and micropore effects in the adsorption of AOCs by carbonaceous porous adsorbents. In the absence of the molecular sieving effect, a linear relationship was found between the adsorption capacities of AOCs and the surface areas of adsorbents, independent of the type of adsorbent. On the other hand, the pore volume occupancies of the adsorbents followed the order of ACF10 > HD4000 > SWNT > MWNT, indicating that the availability of adsorption site was related to the pore size distributions of the adsorbents. ACF10 and HD4000 with higher microporous volumes exhibited higher adsorption affinities to low molecular weight AOCs than SWNT and MWNT with higher mesopore and macropore volumes. Due to their larger pore sizes, SWNTs and MWNTs are expected to be more efficient in adsorption of large size molecules. Removal of surface oxygen-containing functional groups from the SWNT enhanced adsorption of AOCs.
A DABCO‐promoted bicyclization/rearrangement reaction has been developed for the synthesis of tetrasubstituted furans from 1,4‐enediones at room temperature. This transformation involves aza‐Michael ...addition, intramolecular bicyclization, and rearrangement processes. In addition, the 4‐ureidofuran‐3‐carboxylate ester products can further be converted to furo3,4‐dpyrimidine‐2,4‐diones through intramolecular substitution cyclization under heating conditions.
A DABCO‐promoted bicyclization/rearrangement reaction has been developed for the synthesis of polysubstituted furans, which produced to furo3,4‐dpyrimidine‐2,4‐diones under heating conditions.
With the significant increase in the production and use of carbon nanotubes (CNTs), they will be inevitably released into aquatic environments. Therefore, the fate and transport of CNTs in aqueous ...solutions have attracted extensive attention. In the present work, the effects of natural organic matter (NOM), solution pH and ionic strength on adsorption of three synthetic organic chemicals (SOCs) by both pristine and surface functionalized single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs) were investigated. The three SOCs (phenanthrene, biphenyl, and 2-phenylphenol) with different planarity, polarity, and hydrogen/electron-donor/acceptor ability, representing typical scenarios for the SOC–CNT interactions, were employed as probe molecules. Among the three background solution characteristics examined, NOM showed the most significant effect on SOC adsorption, while solution pH and ionic strength exhibited minimal or negligible impacts. The presence of NOM greatly suppressed the SOC adsorption by CNTs, and the impact on the SWNTs was higher than that on the MWNTs. The planarity and hydrophobicity of SOCs were two important factors determining the effects of NOM, solution pH and ionic strength on their adsorption by CNTs.
Fracture-related infection (FRI) management has advanced considerably in recent years, offering new possibilities for predictable rates of infection eradication. Debridement, antibiotics, and implant ...retention (DAIR) procedures have shown promise in the treatment of early FRI. This article provides an overview of the principles and indications of DAIR, including the importance of meticulous debridement and the management of dead space. The outcomes of DAIR are discussed, highlighting the range of fracture union rates reported in the literature. The role of antimicrobial suppression in optimizing host biology and facilitating surgical intervention is also explored. While further research is needed to establish optimal treatment strategies, DAIR offers a valuable treatment approach for FRI when specific criteria are met.
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•Alleviation of Cd-induced growth inhibition by ABA is weakened in AIT1-deficient plants.•AIT1 overexpression facilitated exogenous ABA-mediated Cd minimization.•AIT1-mediated ...ABA-induced Cd reduction was associated with IRT1 downregulation.
Soil cadmium (Cd) accumulation presents risks to crop safety and productivity. However, through an exogenous application of abscisic acid (ABA), its accumulation in plants can be reduced and its toxicity mitigated, thereby providing an alternative strategy to counteract Cd contamination of arable soil. In the present study, we demonstrated that exogenous ABA application alleviates Cd-induced growth inhibition and photosynthetic damage in wild-type (Col-0) Arabidopsis plants. However, these positive effects were weakened in the ABA-importing transporter (AIT1)-deficient mutant (ait1). Through further analysis, we found that upon ABA application, the decrease in Cd level significantly differed among ait1, Col-0, and the two AIT1-overexpressing transgenic plants (AIT1ox-1 and AIT1ox-2), suggesting that AIT1 mediates the Cd-reducing effects of ABA. ABA application also inhibited the expression of IRT1, ZIP1, ZIP4, and Nramp1 in Col-0 plants subjected to Cd stress. However, significant differences among the genotypes (ait1, Col-0 and AIT1ox) were only observed in terms of IRT1 expression. Overall, our findings suggest that the suppression of Cd accumulation and restoration of plant growth by exogenous ABA require the ABA-importing activity of AIT1 to inhibit IRT1 expression.
Quantification of steroids possesses a crucial clinical value in early diagnosis and prognosis evaluation of various endocrine diseases. However, it is still challenging to realize feasible analysis ...of estrogens, androgens, progestogens, and corticoids within one single workflow. In this study, two derivatization reactions were newly designed for improvement: (1) acylation of phenolic hydroxyl on estrogens with isonicotinoyl chloride (INC) under the catalysis of 4-dimethylaminopyridine and (2) post-modification of oxime hydroxyl on hydroxylamine-pretreated ketosteroids with INC. Both reactions could conduct instantaneously at room temperature under aqueous conditions. Moreover, the resulting phenolic-INC and oxime-INC esters exhibited favorable MS responses. Through integrating these derivatization strategies with cold-induced phase separation technology, a feasible LC–MS/MS method was developed for simultaneous quantification of 15 multiclass steroids with proper sample consumption (50 μL serum), satisfying sensitivity (lower limit of quantitation at 0.01–5.00 ng/mL) and high throughput (40 min for sample-preparation). The practical applicability was tested by detecting 30 real samples from pregnant and non-pregnant women. The obtained results showed a good agreement with a previous validated methodology.
