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The past few decades have witnessed tremendous development within epoxides. Among the many known reactions involving epoxide, Meinwald rearrangements represent one of the most important and attractive approaches, which can transform epoxides into versatile carbonyl compounds. Given the high efficiency of this protocol, substantial efforts have been made by researchers by utilizing multiple catalyst systems. This review provides an overview of recent advances in the Meinwald rearrangement (from 2014 onward), along with detailed discussions on mechanistic insights. This review aims to highlight the importance and value of these methodologies, thereby promoting further investigation and application.
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An iron-catalyzed ligand free conjugate reduction of α,ß-unsaturated ketones with PMHS (polymethylhydrosiloxane) was reported to deliver the corresponding carbonyl compounds with up to 93% yield. This operationally simple protocol shows a broad substrate scope using readily available PMHS as a cost-effective and easy-to-handle reductive reagent.
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BACKGROUND: Neonates in the neonatal intensive care unit undergo frequent painful procedures. It is essential to reduce pain using safe and feasible methods. PURPOSE: To evaluate the effects of non-nutritional sucking, mother's voice, or non-nutritional sucking combined with mother's voice on repeated procedural pain in hospitalized neonates. METHODS: A quasi-experimental study was conducted in which 141 neonates were selected in a hospital in Changsha, China. Newborns were divided into four groups: non-nutritional sucking (NNS) (n = 35), maternal voice (MV) (n = 35), NNS + MV (n = 34), and control (n = 37) groups. The Preterm Infant Pain Profile-Revised Scale (PIPP-R) was used to assess pain. RESULTS: During the heel prick, the heart rate value and blood oxygen saturation were significantly different between the groups (P < 0.05). Both non-nutritional sucking and maternal voice significantly reduced PIPP-R pain scores of hospitalized newborns (P < 0.05). The pain-relief effect was more robust in the combined group than in other groups. CONCLUSIONS: This study showed that both non-nutritional sucking and the mother's voice alleviated repeated procedural pain in neonates. Therefore, these interventions can be used as alternatives to reduce repeated procedural pain.
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Recien Nacido Prematuro , Dolor Asociado a Procedimientos Médicos , Recién Nacido , Humanos , Talón , Dolor/etiología , Dolor/prevención & control , Manejo del Dolor/métodosRESUMEN
An efficient asymmetric [1,3] O-to-C rearrangement of quinolin-2(1H)-ones enabled by a chiral bisoxazoline/copper complex has been developed. This strategy tolerated a wide range of substrates to provide a series of 1,4-dihydroquinoline-2,3-diones containing a quaternary stereocenter. A further cyclization of the [1,3] O-to-C rearrangement products was also realized, which led to various optically active 3,4-dihydroquinolin-2-ones with broad substrate scope.
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The continued accumulation of halogenated organic pollutants in soil posed a potential threat to ecosystems and human health. In this study, tetrabromobisphenol A (TBBPA) was used as a typical representative of halogenated organic pollutants in soil, for alkali-thermal activated persulfate (PS) treatment. The results of response surface methodology (RSM) showed a optimal debromination efficiency of TBBPA was 88.99 % under the optimum reaction conditions. Quenching experiments and electron paramagnetic resonance (EPR) confirmed that SO4-â¢, HOâ¢, O2-⢠and 1O2 existed simultaneously in the oxidation process. SO4-⢠played a major role in the initial stage of the reaction, and O2-⢠played a major role in the the last stage. Based on density functional theory (DFT) and intermediate products, two degradation pathways were proposed, including debromination reaction and ß bond scission. Moreover, the basic physical and chemical properties of the soil were affected to a certain extent, while the soil surface structure, elements and functional group composition rarely changed. In addition, the T.E.S.T. analysis and biotoxicity tests proved that alkali-thermal activated PS can effectively reduce the toxicity of TBBPA-contaminated soil, which is conducive to the subsequent safe secondary utilization of soil.
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The continuous accumulation of chlorinated organic pollutants in soil poses a potential threat to ecosystems and human health alike. Alkali-catalyzed hydrothermal oxidation (HTO) can successfully remove chlorinated organic pollutants from water, but it is rarely applied to soil remediation. In this work, we assessed this technique to degrade and detoxify triclosan (TCS) in soil and we determined the underlying mechanisms. The results showed a dechlorination efficiency of TCS (100 mg per kg soil) of 49.03 % after 120 min reaction (H2O2/soil ratio 25 mL·g-1, reaction temperature 180 °C in presence of 1 g·L-1 NaOH). It was found that soil organic constituents (humic acid, HA) and inorganic minerals (SiO2, Al2O3, and CaCO3) suppressed the dechlorination degradation of TCS, with HA having the strongest inhibitory effect. During alkali-catalyzed HTO, the TCS molecules were effectively destroyed and humic acid-like or fulvic acid-like organics with oxygen functional groups were generated. Fluorescence spectroscopy analysis showed that hydroxyl radicals (OH) were the dominant reactive species of TCS degradation in soil. On the basis of the Fukui function and the degradation intermediates, two degradation pathways were proposed. One started with cleavage of the ether bond between the benzene rings of TCS, followed by dechlorination and the opening of benzene via oxidation. The other pathway started with direct hydroxylation of the benzene rings of TCS, after which they were opened and dechlorinated through oxidation. Analysis of the soil structure before and after treatment revealed that the soil surface changed from rough to smooth without affecting soil surface elements. Finally, biotoxicity tests proved that alkali-catalyzed HTO effectively reduced the toxicity of TCS-contaminated soil. This study suggests that alkali-catalyzed hydrothermal oxidation provides an environmentally friendly approach for the treatment of soil contaminated with chlorinated organics such as TCS.
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Contaminantes Ambientales , Triclosán , Contaminantes Químicos del Agua , Humanos , Triclosán/metabolismo , Sustancias Húmicas , Suelo , Peróxido de Hidrógeno , Álcalis , Benceno , Ecosistema , Dióxido de Silicio , Catálisis , Contaminantes Químicos del Agua/análisisRESUMEN
Tungsten (W) is a critical material that is widely used in military applications, electronics, lighting technology, power engineering and the automotive and aerospace industries. In recent decades, overexploitation of W has generated large amounts of mine waste rocks, which generate elevated content of toxic elements and cause serious adverse effects on ecosystems and public health. Microorganisms are considered important players in toxic element migrations from waste rocks. However, the understanding of how the microbial community structure varies in W mine waste rocks and its key driving factors is still unknown. In this study, high-throughput sequencing methods were used to determine the microbial community profiles along a W content gradient in W mine waste rocks. We found that the microbial community structures showed clear differences across the different W levels in waste rocks. Notably, arsenic (As), instead of W and nutrients, was identified as the most important predictor influencing microbial diversity. Furthermore, our results also showed that As is the most important environmental factor that regulates the distribution patterns of ecological clusters and keystone ASVs. Importantly, we found that the dominant genera have been regulated by As and were widely involved in As biogeochemical cycling in waste rocks. Taken together, our results have provided useful information about the response of microbial communities to W mine waste rocks.
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Arsénico , Microbiota , TungstenoRESUMEN
Ceftiofur (CEF) residues in animal-derived foods are of great concern to farmers, regulatory agencies and consumers. In this study, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method was established to quickly monitor CEF residues in edible animal tissues using an easy sample preparation procedure. A monoclonal antibody, 4D5, against CEF has been produced at first, which had IC50 values for CEF, ceftriaxone, cefquinome, cefotaxime and desfuroylceftiofur of 0.78 µg/L, 0.73 µg/L, 13.6 µg/L, 8.99 µg/L and 8.89 µg/L, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) in artificially contaminated animal-derived foods were 0.12-0.19 µg/L and 0.20-0.30 µg/L. The recovery rates were in the range of 89.7-109.0%. The CVs were less than 6.7%. A good correlation (R= 0.9994) between the ic-ELISA and UPLC-MS/MS showed the reliability of the developed ic-ELISA. The ic-ELISA produces a sensitive, accurate and low-cost tool for the screening of residues of CEF in animal-derived foods.
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Anticuerpos Monoclonales , Cefalosporinas/análisis , Residuos de Medicamentos/análisis , Ensayo de Inmunoadsorción Enzimática , Carne/análisis , Animales , Cromatografía Liquida , Reproducibilidad de los Resultados , Espectrometría de Masas en TándemRESUMEN
To monitor the residue of kitasamycin (KIT), a monoclonal antibody against KIT was prepared, and a 50% inhibition concentration (IC50) of 5.7 ± 1.4 µg/L was achieved with the most sensitive antibody, KA/2A9, by optimizing ELISA conditions. The LODs for KIT in different animal tissues ranged from 22.47 µg/kg to 29.32 µg/kg, and the recoveries of the fortified tissues were 70% ~ 120% with coefficients of variation below 20%. Then, KIT-specific scFv KA/2A9/3 was prepared for the first time. Homologous modeling and molecular docking results indicated that the key amino acids of KA/2A9/3 scFv are TYR-92 (CDRL3), SER-93 (CDRL3), ASP-155 (CDRH1) and GLY-226 (CDRH3), and the hydrogen bond is the main force. And then, virtual mutation provides a method to evolve KA/2A9/3 scFv antibodies. These results contribute to comprehending the antigen-antibody binding mechanism and provide effective information for in vitro affinity maturation of anti-KIT scFv.
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Kitasamicina , Anticuerpos de Cadena Única , Animales , Reacciones Antígeno-Anticuerpo , Ensayo de Inmunoadsorción Enzimática , Simulación del Acoplamiento Molecular , Anticuerpos de Cadena Única/genéticaRESUMEN
An enantioselective synthesis of α-aminoketone derivatives were readily available through a tandem insertion-[1,3] O-to-C rearrangement reaction. The rhodium salt and chiral N,N'-dioxide-indium(III) complex make up relay catalysis, which enables the O-H insertion of benzylic alcohols to N-sulfonyl-1,2,3-triazoles, and asymmetric [1,3]-rearrangement of amino enol ether intermediates, subsequently. Preliminary mechanistic studies suggested that the [1,3] O-to-C rearrangement step proceeded through an ion pair pathway.
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OBJECTIVE: To investigate the effect of placement of peripherally inserted central catheter (PICC) via the upper versus lower extremity veins in neonates through a Meta analysis. METHODS: CNKI, Wanfang Data, VIP Data, CBMdisc, PubMed, Web of Knowledge, Embase, Medline, Cochrane Library and Google Scholar were searched for control studies on the effect of PICC placement via the upper versus lower extremity veins in neonates. RevMan 5.3 was used to perform a Meta analysis of the studies which met the inclusion criteria. RESULTS: A total of 18 studies were included, among which there were 8 randomized controlled trials and 10 cohort studies, with 4 890 subjects in total. Compared with those undergoing PICC placement via the upper extremity veins, the neonates undergoing PICC placement via the lower extremity veins had significantly lower incidence rates of complications (RR=0.83, 95%CI: 0.75-0.92, P<0.05), catheter-related infections (RR=0.77, 95%CI: 0.60-0.99, P<0.05), catheter malposition (RR=0.28, 95%CI: 0.18-0.42, P<0.05), extravasation of the infusate (RR=0.52, 95%CI: 0.40-0.70, P<0.05), and unplanned extubation (RR=0.82, 95%CI: 0.69-0.98, P<0.05). They also had a significantly higher first-attempt success rate of puncture (RR=1.17, 95%CI: 1.05-1.30, P<0.05) and a significantly shorter PICC indwelling time (MD=-0.93, 95%CI: -1.26-0.60, P<0.05). CONCLUSIONS: The above evidence shows that PICC placement via the lower extremity veins has a better effect than PICC placement via the upper extremity veins in neonates.
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Cateterismo Venoso Central , Cateterismo Periférico , Estudios de Cohortes , Humanos , Recién Nacido , Extremidad Inferior , Estudios RetrospectivosRESUMEN
Although isocyanide-based multicomponent reactions were proven to be simple, elegant and facile strategies for the synthesis of highly valuable nitrogen-containing heterocycles, their asymmetric versions accessing to optically active nitrogen heterocyclic compounds are rather limited. Here, we illustrate that, relying on the enantioselective addition of simple isocyanides to C=C bonds, several isocyanide-based multicomponent reactions are realized in the presence of a chiral MgII-N,N'-dioxide catalyst. In the reaction among isocyanide, TMSN3, and alkylidene malonate, three- or four-component reactions could be precisely controlled by modulating reaction conditions, supplying two types of enantioenriched tetrazole-derivatives in moderate to high yields. Possible catalytic cycles via a key zwitterionic intermediate, and the vital roles of H2O or excess ligand are provided based on control experiments. Moreover, taking advantage of this zwitterionic intermediate as a 1,3-dipole, an enantioselective dearomative [3+2] annulation reaction of nonactivated isoquinolines is achieved, furnishing chiral 1,2-dihydroisoquinolines in good to excellent results.
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OBJECTIVE: To study the clinical effect of maternal voice stimulation in alleviating procedural pain in neonates during heel blood collection. METHODS: A total of 72 neonates who were admitted to the neonate intensive care unit were randomly divided into an intervention group (n=35) and a control group (n=37). Heel blood collection was performed by the routine method in the control group. The intervention group listened to their mothers' voice from 1 minute before heel blood collection to the end of the procedure. Pain score, incidence of crying, and vital signs were recorded before and after heel blood collection. RESULTS: Compared with the control group, the heart rate was significantly reduced, the blood oxygen saturation significantly increased, the incidence of crying and the pain score were significantly reduced in the intervention group during the procedure of heel blood collection (P<0.05). CONCLUSIONS: Maternal voice stimulation helps to reduce procedural pain and maintain stable vital signs in neonates.
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Dolor Asociado a Procedimientos Médicos , Llanto , Femenino , Humanos , Recién Nacido , Unidades de Cuidado Intensivo Neonatal , Madres , Manejo del Dolor , HablaRESUMEN
The first example of catalytic insertion/asymmetric Claisen rearrangement tandem reaction of N-sulfonyl-1,2,3-triazoles with allyl alcohol esters was achieved by bimetallic relay catalytic systems involving achiral rhodium salt and chiral N,N'-dioxide-indium(III) complex. This manifold could overcome the limitation of single RhII catalysis, providing a straight and facile route to various enantioenriched ß/γ-amino acid derivatives in high yields (up to 99 %) with excellent diastereo- and enantioselectivities (up to >95:5 dr, 98:2 er). Moreover, possible transition state models were proposed to elucidate the origin of chiral induction based on the control experiments and X-ray crystal structure of the catalyst.
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We report the development of a chiral guanidine-based copper(I) catalyst for the asymmetric azide-alkyne cycloaddition/[2+2] cascade reaction. Optically active spiroazetidinimine oxindoles were constructed by trapping the ketenimine species under mild reaction conditions. High level of enantioinduction and excellent isolated yields were achieved in the three-component reaction of various isatin-derived ketimines, sulfonyl azides, and terminal alkynes. Control experiments and X-ray crystallography were used to probe into the interaction of chiral guanidinium salt with copper salt.
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Cancer stem cells (CSCs) are considered to be the root cause for cancer treatment failure. Thus, there remains an urgent need for more potent and safer therapies against CSCs for curing cancer. In this study, the antitumor activity of cytokine-induced killer (CIK) cells against putative CSCs of nasopharyngeal carcinoma (NPC) was fully evaluated in vitro and in vivo. To visualize putative CSCs in vitro by fluorescence imaging, and image and quantify putative CSCs in tumor xenograft-bearing mice by in vivo bioluminescence imaging, NPC cells were engineered with CSC detector vector encoding GFP and luciferase (Luc) under control of Nanog promoter. Our study reported in vitro intense tumor-killing activity of CIK cells against putative CSCs of NPC, as revealed by percentage analysis of side population cells, tumorsphere formation assay and Nanog-promoter-GFP-Luc reporter gene strategy plus time-lapse recording. Additionally, time-lapse imaging firstly illustrated that GFP-labeled or PKH26-labeled putative CSCs or tumorspheres were usually attacked simultaneously by many CIK cells and finally killed by CIK cells, suggesting the necessity of achieving sufficient effector-to-target ratios. We firstly confirmed that NKG2D blockade by anti-NKG2D antibody significantly but partially abrogated CIK cell-mediated cytolysis against putative CSCs. More importantly, intravenous infusion of CIK cells significantly delayed tumor growth in NOD/SCID mice, accompanied by a remarkable reduction in putative CSC number monitored by whole-body bioluminescence imaging. Taken together, our findings suggest that CIK cells demonstrate the intense tumor-killing activity against putative CSCs of NPC, at least in part, by NKG2D-ligands recognition. These results indicate that CIK cell-based therapeutic strategy against CSCs presents a promising and safe approach for cancer treatment.
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Células Asesinas Inducidas por Citocinas/trasplante , Inmunoterapia Adoptiva/métodos , Subfamilia K de Receptores Similares a Lectina de Células NK/metabolismo , Neoplasias Nasofaríngeas/patología , Células Madre Neoplásicas/patología , Animales , Western Blotting , Carcinoma , Separación Celular , Citometría de Flujo , Humanos , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Ratones , Ratones Endogámicos NOD , Ratones SCID , Carcinoma Nasofaríngeo , Neoplasias Nasofaríngeas/metabolismo , Células Madre Neoplásicas/metabolismo , Transducción Genética , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Huanglian Wan (HLW) is a prescription of traditional Chinese medicine (TCM), which has been used to treat diabetes mellitus for thousands of years in China. In this study we provide experimental evidence for the clinical use of HLW in the treatment of diabetes mellitus. MATERIALS AND METHODS: HLW extract was prepared and the main components (namely berberine and catalpol) contained in the extract were assayed with high performance liquid chromatography (HPLC), and diabetic model rats were induced by intraperitoneal injection of streptozotocin (STZ). After grouped randomly, diabetic rats were administered low or high dose of HLW extract, acarbose and vehicle for 33 days, respectively. Body weight, food intake, urine volume, urine sugars, fasting plasma glucose and fasting plasma insulin were monitored to evaluate its antidiabetic effects in diabetic rats. Intestinal mucosa homogenate was prepared and the activities of intestinal disaccharidases were assayed. Moreover, oral sucrose tolerance test (OSTT) was performed and the inhibitory effect of HLW extract on the maltase and sucrase in vitro was evaluated. RESULTS: After the treatment of HLW extract, the body weight and the fasting plasma insulin level were found to be increased while food intake, urine volume, urine sugars and fasting plasma were decreased. OSTT showed that HLW extract could lower the postprandial plasma glucose level of diabetic rats. Furthermore, HLW extract could inhibit the activities of sucrase and maltase in vitro. CONCLUSIONS: According to our present findings, the TCM prescription HLW possessed potent anti-hyperglycemic effect on STZ-induced diabetic rats. And HLW extract exerted anti-hyperglycemic effect partly via inhibiting the increased activities of intestinal disaccharidases and elevating the level of plasma insulin in diabetic rats induced by streptozotocin.
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Diabetes Mellitus Experimental/tratamiento farmacológico , Hipoglucemiantes/uso terapéutico , Medicina Tradicional China , Extractos Vegetales/uso terapéutico , Animales , Berberina/análisis , Glucemia/análisis , Diabetes Mellitus Experimental/metabolismo , Inhibidores de Glicósido Hidrolasas , Hipoglucemiantes/análisis , Hipoglucemiantes/farmacología , Insulina/sangre , Intestinos/enzimología , Glucósidos Iridoides/análisis , Lactasa/metabolismo , Masculino , Fitoterapia , Extractos Vegetales/análisis , Extractos Vegetales/farmacología , Ratas , Ratas Sprague-Dawley , Sacarasa/antagonistas & inhibidores , Sacarasa/metabolismo , alfa-Glucosidasas/metabolismoRESUMEN
During diabetes, structural and functional changes in the alimentary tract are known to take place resulting in an increased absorption of intestinal glucose and alterations in the activities of brush-border disaccharidases. To elucidate the effect of administrating polysaccharide from Gynura divaricata (PGD) on disaccharidase activities, the specific activities of intestinal disaccharidases, namely sucrase, maltase and lactase, were measured in streptozotocin-induced diabetic rats. Normal control and diabetic rats were treated by oral administration with PGD. Specific activities of intestinal disaccharidases were increased significantly during diabetes, and amelioration of the activities of sucrase and maltase during diabetes was clearly visible by the treatment with PGD. However, the increased activity of lactase during diabetes mellitus was remarkably alleviated by the administration of PGD only in the duodenum. Meanwhile, oral sucrose tolerance tests demonstrated that PGD alleviated the hyperglycaemia during diabetes mellitus, resulting from the amelioration in the activities of intestinal disaccharidases. The present investigation suggests that PGD exerted an anti-diabetic effect partly via inhibiting the increased intestinal disaccharidase activities of diabetic rats. This beneficial influence of administration of PGD on intestinal disaccharidases clearly indicates their helpful role in the management of diabetes.