Reaction between Azidyl Radicals and Alkynes: A Straightforward Approach to NHâ 1,2,3â Triazoles

Reaction between nitrogenâ centered radicals and unsaturated Câ C bonds is an effective synthetic strategy for the construction of nitrogenâ containing molecules. Although the reactions between nitrogenâ centered radicals and alkenes have been studied extensively, their counterpart reactions with alkynes are extremely rare. Herein, the first example of reactions between azidyl radicals and alkynes is described. This reaction initiated an efficient cascade reaction involving interâ /intramolecular radical homolytic addition toward a Câ C triple bond and a hydrogenâ atom transfer step to offer a straightforward approach to NHâ 1,2,3â triazoles under mild reaction conditions. Both the internal and terminal alkynes work well for this transformation and some heterocyclic substituents on alkynes are compatible. This mechanistically distinct strategy overcomes the inherent limitations associated with azide anion chemistry and represents a rare example of reactions between a nitrogenâ centered radicals and alkynes.Get radical! Although the reactions between nitrogenâ centered radicals and alkenes have been studied extensively, their counterpart reactions with alkynes are extremely rare. Herein, the first example of reactions between azidyl radicals and alkynes is described (see scheme).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137186/1/chem201504515.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137186/2/chem201504515-sup-0001-misc_information.pd

Giant Brunner’s gland adenoma of the duodenum complicated with bleeding: a case report

Brunner’s gland adenoma（BGA） of the duodenum is an extremely rare benign tumor in clinical practice. In this article， the diagnosis and treatment of one case of BGA of the duodenum were reported. The patient had a history of anemia for 4 years， but she never received tests to identify the cause. She was admitted to Department of Neurology for the first time due to dizziness， and was transferred to our department due to gastrointestinal bleeding during hospitalization. Hemorrhagic shock and transient syncope occurred during treatment， which were alleviated after drug therapy. Then， gastroscopy was immediately performed and showed protrusion lesions in the descending duodenum. The diagnosis of BGA was finally confirmed by endoscopic pathological resection. This article aiming to deepen the gastroenterologists / endoscopists’ understanding of BGA and improve the diagnostic and therapeutic levels

Expression Analysis of MYC Genes from Tamarix hispida in Response to Different Abiotic Stresses

The MYC genes are a group of transcription factors containing both bHLH and ZIP motifs that play important roles in the regulation of abscisic acid (ABA)-responsive genes. In the present study, to investigate the roles of MYC genes under NaCl, osmotic and ABA stress conditions, nine MYC genes were cloned from Tamarix hispida. Real-time reverse-transcriptase (RT)-PCR showed that all nine MYC genes were expressed in root, stem and leaf tissues, but that the levels of the transcripts of these genes in the various tissues differed notably. The MYC genes were highly induced in the roots in response to ABA, NaCl and osmotic stresses after 3 h; however, in the stem and leaf tissues, MYC genes were highly induced only when exposed to these stresses for 6 h. In addition, most of these MYC genes were highly expressed in roots in comparison with stems and leaves. Furthermore, the MYC genes were more highly induced in roots than in stem and leaf tissues, indicating that these genes may play roles in stress responses mainly in the roots rather than the stems and leaves. The results of this present study suggest that MYCs are involved in salt and osmotic stress tolerances and are controlled by the ABA signal transduction pathway

Two new species of Paramesosciophilodes (Diptera, Nematocera, Mesosciophilidae) from the Middle Jurassic of China

Two new species, Paramesosciophilodes bellus sp. n. and Paramesosciophilodes rarissima sp. n., from the Jiulongshan Formation at Daohugou Village, Inner Mongolia, China, are described in the extinct family Mesosciophilidae. Altogether seven genera with 21 species of mesosciophilids have been described from the Jurassic of Siberia and Kazakhstan, the Lower Cretaceous of Transbaikalia, and the Middle Jurassic of Inner Mongolia. An emended generic diagnosis of Paramesosciophilodes and a list of known taxa of mesosciophilids are provided

An accident prevention and emergency rescue system for expressway tunnels

Paper presented at the 25th Annual Southern African Transport Conference 10 - 13 July 2006 "2010: Will transport infrastructure and systems be ready?", CSIR International Convention Centre, Pretoria, South Africa.This paper was transferred from the original CD ROM created for this conference. The material on the CD ROM was published using Adobe Acrobat technology. The original CD ROM was produced by Document Transformation Technologies Postal Address: PO Box 560 Irene 0062 South Africa. Tel.: +27 12 667 2074 Fax: +27 12 667 2766 E-mail: [email protected] URL: http://www.doctech.co.z

Polyethylene Terephthalate Fiber Modified with Type I Collagen as a 3D Scaffold Material for Bioartificial Liver

Acute and chronic liver failure are clinically significant conditions, and the artificial liver support system (ALSS) is emerging as a novel and effective approach for the clinical management of liver failure. Within this framework, scaffold materials occupy a pivotal position as integral components of the bioreactor. Elevating the performance capabilities of these scaffolds not only augments the therapeutic efficacy of the artificial liver but also lays the groundwork for refining and selecting large-scale hepatocyte culture models. In this study, we introduced a novel hepatocyte scaffold material designated as PET-COL, crafted by coating polyethylene terephthalate (PET) with collagen. This involved a sequence of modifications, including alkaline hydrolysis, EDC/NHS activation and crosslinking, as well as collagen conjugation. The physicochemical attributes of the scaffold were thoroughly characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), second harmonic generation (SHG), water contact angle measurements, and high-performance liquid chromatography–mass spectrometry (HPLC-MS). Furthermore, an investigation into the material’s biological properties was conducted that encompassed SEM (HepaRG growth), fluorescence staining (assessment of cell viability), staining by trypan blue (HepaRG counting), CCK-8 (proliferation of cells), biochemical testing, and immunosorbent assay. Our findings revealed that collagen was covalently bonded to the PET surface, leading to a substantial enhancement in the material’s hydrophilicity (p p < 0.001), demonstrating remarkable biological vitality. The PET-COL scaffold, as developed in this study, holds immense potential for application in bioartificial livers

Overexpression of TaLEA gene from Tamarix androssowii improves salt and drought tolerance in transgenic poplar (Populus simonii × P. nigra).

Late embryogenesis abundant (LEA) genes were confirmed to confer resistance to drought and water deficiency. An LEA gene from Tamarixandrossowii (named TaLEA) was transformed into Xiaohei poplar (Populussimonii × P. nigra) via Agrobacterium. Twenty-five independent transgenic lines were obtained that were resistant to kanamycin, and 11 transgenic lines were randomly selected for further analysis. The polymerase chain reaction (PCR) and ribonucleic acid (RNA) gel blot indicated that the TaLEA gene had been integrated into the poplar genome. The height growth rate, malondialdehyde (MDA) content, relative electrolyte leakage and damages due to salt or drought to transgenic and non-transgenic plants were compared under salt and drought stress conditions. The results showed that the constitutive expression of the TaLEA gene in transgenic poplars could induce an increase in height growth rate and a decrease in number and severity of wilted leaves under the salt and drought stresses. The MDA content and relative electrolyte leakage in transgenic lines under salt and drought stresses were significantly lower compared to those in non-transgenic plants, indicating that the TaLEA gene may enhance salt and drought tolerance by protecting cell membranes from damage. Moreover, amongst the lines analyzed for stress tolerance, the transgenic line 11 (T11) showed the highest tolerance levels under both salinity and drought stress conditions. These results indicated that the TaLEA gene could be a salt and drought tolerance candidate gene and could confer a broad spectrum of tolerance under abiotic stresses in poplars

Wind-Induced Response Analysis and Fatigue Reliability Study of a Steel–Concrete Composite Wind Turbine Tower

Taking an actual 3MW steel–concrete composite wind turbine tower as an example, a finite element model of the tower structure was established, and static bearing capacity and dynamic time history response analyses were performed to identify the locations where the structure is prone to failure. On this basis, the fatigue lives of the turbine tower at the most unfavorable locations were predicted using linear cumulative damage theory, and the fatigue reliability at the corresponding locations of the structure was calculated using the kriging–subset simulation method. The most dangerous locations of the tower that are most prone to failure are as follows: the bottom of the leeward side of the upper steel tube, the flange of the steel tube, the bolt-hole imprinting surface of the flange, the leeward side of the transition tube, and the top of the leeward side of the concrete tube. The failure risk of the flange and bolt-hole imprinting surface of the upper steel tube is relatively high, followed by that of the transition tube. This indicates that special attention should be given to the design and daily maintenance of this part. The fatigue resistance of the tower can be enhanced by improving the strength of the flange plate or increasing the number of bolts and strengthening the transition tube