Search results for "Derivative"

ChemInform Abstract: A Quantitative Study of Substituent Effects on Oxidative Cyclization of Some 2-Methylsubstituted Aldehydes. Thiosemicarbazones I…

2010

In order to gain further mechanistical information about the cyclization of thiosemicarbazones and thiosemicarbazone-type substrates induced by metallic salts as oxidizing agents, we performed the synthesis of substrates 1a-s and a kinetic study of the oxidative cyclization of 1 to 5-imino-Δ2-1,3,4-thiadiazole 2 and 1,2,4-triazoline-5-thione 3 derivatives induced by methanolic ferric chloride solutions. The results of cyclization were compared to those of corresponding semicarbazones. The kinetic data were analyzed by means of the Hammett's equation and ρ values discussed.

Oxidative stress induced by the novel compound tributyltin(iv) ferulate promotes ER stress and autophagy in colon cancer cells

2021

Discovery of the 3-Amino-1,2,4-triazine-Based Library as Selective PDK1 Inhibitors with Therapeutic Potential in Highly Aggressive Pancreatic Ductal …

2023

Pyruvate dehydrogenase kinases (PDKs) are serine/threonine kinases, that are directly involved in altered cancer cell metabolism, resulting in cancer aggressiveness and resistance. Dichloroacetic acid (DCA) is the first PDK inhibitor that has entered phase II clinical; however, several side effects associated with weak anticancer activity and excessive drug dose (100 mg/kg) have led to its limitation in clinical application. Building upon a molecular hybridization approach, a small library of 3-amino-1,2,4-triazine derivatives has been designed, synthesized, and characterized for their PDK inhibitory activity using in silico, in vitro, and in vivo assays. Biochemical screenings showed that …

The stability and functional properties of proteoliposomes mixed with dextran derivatives bearing hydrophobic anchor groups

1992

Liposomes composed of Escherichia coli phospholipid were coated with polysaccharides bearing hydrophobic palmitoyl anchors. The effect on the stability of liposomes without or with integral membrane proteins was investigated. A high concentration of hydrophobized dextrans protected the liposomes against detergent degradation, decreased the fluidity of the membranes, prevented fusion of the liposomes and enhanced their stability. Proteoliposomes containing beef heart cytochrome-c oxidase and the lactose transport carrier of E. coli were similarly affected by coating with the dextrans. Under these conditions both membrane proteins were still active. Long-term stability of the coated liposomes…

Development of natural and synthetic compounds as kinase inhibitors targeting cancer cells and cancer stem cells

2023

Identification of lipophilic pollutants discharged from a Finnish pulp and paper mill.

1998

Lipophilic organic compounds originating from kraft pulping and papermaking were identified by straight gas chromatography/mass spectrometry (GC/MS) analyses. Samples analyzed included a primary clarifier effluent (PE) and a secondary clarifier effluent (SE) from the activated sludge treatment plant of a Finnish ECF-bleached (Elementally Chlorine Free) kraft pulp and paper mill. Liquid-liquid extraction composition of PE was compared with solid phase extraction (SPE) and dialysis of a semipermeable membrane device (SPMD) exposed to PE. Dichloromethane extracts of particulate material isolated from PE, sludges from both the primary and secondary clarifier, a sediment collected in the vicinit…

Monitoring the Early Steps of Unfolding of Dicalcium and Mono-Ce3+-Substituted Forms of P43M Calbindin D9k

2003

Early steps of unfolding of P43M Calbindin D9k have been evaluated by NMR spectroscopy on the native dicalcium and on the paramagnetic monocerium-substituted derivative. Although at 2 M GdmHCl the ...

An Automatic Differentiation Based Approach to the Level Set Method

2015

This paper discusses an implementation of the parametric level set method. Adjoint approach is used to perform the sensitivity analysis, but contrary to standard implementations, the state problem is differentiated in its discretized form. The required partial derivatives are computed using tools of automatic differentiation, which avoids the need to derive the adjoint problem from the governing partial differential equation. The augmented Lagrangian approach is used to enforce volume constraints, and a gradient based optimization method is used to solve the subproblems. Applicability of the method is demonstrated by repeating well known compliance minimization studies of a cantilever beam …

Strain gradient elasticity within the symmetric BEM formulation

2014

The symmetric Galerkin Boundary Element Method is used to address a class of strain gradient elastic materials featured by a free energy function of the (classical) strain and of its (first) gradient. With respect to the classical elasticity, additional response variables intervene, such as the normal derivative of the displacements on the boundary, and the work-coniugate double tractions. The fundamental solutions - featuring a fourth order partial differential equations (PDEs) system - exhibit singularities which in 2D may be of the order 1/ r 4 . New techniques are developed, which allow the elimination of most of the latter singularities. The present paper has to be intended as a resear…

Response of nonlinear oscillators with fractional derivative elements under evolutionary stochastic excitations: A Path Integral approach based on La…

2023

In this paper, an approximate analytical technique is developed for determining the non-stationary response amplitude probability density function (PDF) of nonlinear/hysteretic oscillators endowed with fractional element and subjected to evolutionary excitations. This is achieved by a novel formulation of the Path Integral (PI) approach. Specifically, a stochastic averaging/linearization treatment of the original fractional order governing equation of motion yields a first-order stochastic differential equation (SDE) for the oscillator response amplitude. Associated with this first-order SDE is the Chapman–Kolmogorov (CK) equation governing the evolution in time of the non-stationary respon…