Search results for "Bridge"

Influence of bond deterioration on shear-flexure failure of prestressed girders with post-tensioned tendons

2021

Internal prestressing with bonded tendons suffers corrosion of wires and bond deterioration due to the bad infill of grouted sheaths. Many bridge girders show this state through cracking, deflections and in the worst cases, sudden failures. In Italy these are common situations, and the internal tendon corrosion is among the major causes of bridge degradation and damage, especially for grouted post-tensioned tendons. This paper presents the analysis of failure of prestressed cross-sections considering shear and flexure in the case of bond deterioration due to corrosion of internal post-tensioned tendons. The structural behaviour is analysed for different typologies of bridge deck composed of…

Metabolism of Thiodan® in Insects

1966

Modulating the reaction pathway of phenyl diazonium ions using host–guest complexation with cucurbit[7]uril

2022

Aryl diazonium ions are known to be an important intermediate in the divergent synthesis of azo compounds and substituted aromatics. The presence of more than one electrophilic center in a diazonium ion could lead to undesirable side reactions during a synthesis. Herein, we report that the electrophilic α-carbon on a phenyl diazonium [PhN2]+ ion can be selectively deactivated upon host–guest complexation with cucurbit[7]uril (CB7) in aqueous media, achieving a ∼60-fold increase in the half-life of [PhN2]+. Notably, however, the electrophilic nitrogen of the encapsulated diazonium ion remains active towards diazo coupling with strong nucleophiles, allowing the formation of azo compounds usin…

Global treatment patterns and outcomes among patients with recurrent and/or metastatic head and neck squamous cell carcinoma: Results of the GLANCE H…

2020

Abstract Objectives Given a lack of universally-accepted standard-of-care treatment for patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC), study objectives were to assess treatment utilization and survival outcomes for R/M HNSCC in the real-world setting. Materials and methods A multi-site retrospective chart review was conducted in Europe (Germany, United Kingdom, Italy, Spain), Asia Pacific (Australia, South Korea, Taiwan), and Latin/North America (Brazil and Canada) to identify patients who initiated first-line systemic therapy for R/M HNSCC between January 2011 and December 2013. Patients were followed through December 2015 to collect clinical characte…

Dimerization control in the self-assembly behavior of copillar[5]arenes bearing ω-hydroxyalkoxy groups.

2012

Two novel copillar[5]arenes bearing ω-hydroxyalkoxy groups are synthesized and their self-assembly properties are studied by (1)H NMR spectroscopy, specific viscosity, and X-ray measurements. The copillar[5]arene 2b bearing a 6-hydroxyhexyloxy group exhibits a reversible self-assembly behavior, leading to the formation of the self-inclusion monomer and hugging dimers. The reversible self-assembly behavior can be controlled by tuning solvent, temperature, guest, and H-bond interaction. However, the copillar[5]arene 2a bearing a short 4-hydroxybutyloxy group does not show such a self-assembly behavior to the formation of the self-inclusion monomer and hugging dimers.

The complex formation of tetracyclohexylammonium C1-resorcinarene with various guests - an electrospray ionization Fourier transform ion cyclotron re…

2008

The complex formation of a tetraammonium C1-resorcinarene (R+4HCl) was studied using electrospray ionization Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry. Although R+4HCl easily loses its counter ions in the ESI process, a neutral self-assembled structure with an intramolecular circular hydrogen-bonded 16-membered -N(+)-H ... X(-) ... H-N(+)- array with ammonium ion as the charge-giving species was observed in the gas phase. In addition to chloride, several other counter ions were also studied. The size and basicity of the counter ion as well as the size of the charge-giving cation strongly affected the gas-phase stability of the self-assembled system. H/D exchang…

Gephyromycin, the first bridged angucyclinone, from Streptomyces griseus strain NTK 14

2005

The new, highly oxygenated angucyclinone gephyromycin was isolated from an extract of a Streptomyces griseus strain. Its unprecedented ether-bridged structure was elucidated by NMR methods and substantiated by single crystal X-ray analysis. The absolute configuration was evidenced by quantum chemical CD calculations. Gephyromycin exhibits glutaminergic activity towards neuronal cells. Furthermore, the known compounds fridamycin E and dehydrorabelomycin were identified.

One-Pot Synthesis and AFM Imaging of a Triangular Aramide Macrocycle

2014

Macrocyclizations in exceptionally good yields were observed during the self-condensation of N-benzylated phenyl p-aminobenzoates in the presence of LiHMDS to yield three-membered cyclic aramides that adopt a triangular shape. An ortho-alkyloxy side chain on the N-benzyl protecting group is necessary for the macrocyclization to occur. Linear polymers are formed exclusively in the absence of this Li-chelating group. A model that explains the lack of formation of other cyclic congeners and the demand for an N-(o-alkoxybenzyl) protecting group is providedon the basis of DFT calculations.High-resolution AFM imaging of the prepared molecular triangles on a calcite(10.4) surface shows individual …

SNPs and taxane toxicity in breast cancer patients

2014

Aim: In order to identify genetic variants associated with taxanes toxicity, a panel with 47 SNPs in 20 genes involved in taxane pathways was designed. Patients & methods: Genomic DNA of 113 breast cancer patients was analyzed (70 taking docetaxel, 43 taking paclitaxel). Results: Two SNPs associated with docetaxel toxicity were identified: CYP3A4*1B with infusion-related reactions; and ERCC1 Gln504Lys with mucositis (p ≤ 0.01). Regarding paclitaxel toxicity: CYP2C8 HapC and CYP2C8 rs1934951 were associated with anemia; and ERCC1 Gln504Lys with neuropathy (p ≤ 0.01). Conclusion: Genes involved in DNA repair mechanisms and reactive oxygen species levels influence taxane toxicity in cance…

Relationship Between Thymidylate Synthase and p53 and Response to FEC Versus Taxane Adjuvant Chemotherapy for Breast Carcinoma

2011

Many drugs can be used for adjuvant therapy of breast cancer, including anthracyclines, cyclophosphamide, 5-fluorouracil (5-fU) and, recently, taxanes (TXT) have shown promising results. 5-FU blocks thymidylate synthase (TS) which cross-links p53 mRNA, inhibiting its synthesis. TS overexpression is one of the main mechanisms involved in 5-FU drug resistance. Enough p53 mutations can confer resistance to chemotherapy using anthracyclines and 5-FU, while are associated with improved responses to TXT. The aim of this study was to examine the TS and p53 levels in tumor samples and to compare the efficacy of FEC (5-FU, epirubicin, cyclophosphamide) and TXT chemotherapy in a group of patients wit…