The reactivity enhancement in Diels–Alder cycloaddition of 1,3-diene by cation encapsulation to C60: a computational insight

The origin of the experimentally known preference for [6,6] bonds in cycloaddition reactions involving C₆₀ has been computationally explored. To this end, we examined the reactions of 1,3-dienes with fullerene (C₆₀) in the context of an approach to open a large orifice on the fullerene framework by using the activation model of reactivity in combination with the energy analysis method. In this study, the effect of the alkali metal of Li⁺, Na⁺, and K⁺ as an encapsulated element was investigated on the kinetic and thermodynamic behaviors of the Diels–Alder (DA) process. Our calculations indicated that encapsulated Na⁺ and K⁺ cations are located close to the center of the C₆₀ molecule; however, encapsulated Li⁺ is displaced from the center, which leads to a higher reactivity for Li⁺@C₆₀ in DA cycloaddition reaction in the gas phase. Also, benzene as a non-polar solvent affects the DA reactions greater than water as a polar solvent. Different analyses show that solvent changes the catalysis reaction performance, in which a greater efficiency was obtained for K⁺ in the solvent in comparison with other alkali ions because of a facilitated mechanism of electron transfer.

     

Expression of miRNAs Targeting <Emphasis Type="Italic">mTOR</Emphasis> and <Emphasis Type="Italic">S6K1</Emphasis> Genes of mTOR Signaling Pathway Including miR-96, miR-557, and miR-3182 in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer. Aberrant expression of genes in mTOR pathway and their targeting miRNAs plays an important role in TNBC. The aim of this study was to determine the expression of mTOR and S6K1 and their targeting miRNAs in breast cancer cell lines and clinical samples. miRNAs targeting 3′-UTR of mTOR and S6K1 mRNAs were predicted using bioinformatic algorithms. MDA-MB-231, MCF-7, and MCF-10A as well as 20 TNBC samples were analyzed for gene and miRNA expression using quantitative real-time PCR (RT-qPCR). A receiver operating characteristic (ROC) curve analysis was performed for evaluation of candidate miRNAs as diagnostic biomarkers. miR-96 and miR-557 targeting mTOR and S6K1 mRNAs, respectively, were selected, and miR-3182 was selected as the miRNA targeting both genes. The miRNAs were down-regulated in cell lines, while their target mRNAs were up-regulated. Similar findings were observed in clinical samples. The ROC curve analysis revealed decline in expression of these miRNAs. We suggest that miR-96, miR-557, and miR-3182 can be used as inhibitory agents for mTOR and S6K1 in TNBC-targeted therapy.     

Synthesis of benzodiazepines catalyzed by chitosan functionalized by triacid imide as a superior catalyst

Research on Chemical Intermediates - Chitosan functionalized by triacid imide has been applied as an effective catalyst for the synthesis of benzodiazepines by one-pot reactions of...     

Boundary Behavior of Functions in the de Branges–Rovnyak Spaces

This paper deals with the boundary behavior of functions in the de Branges–Rovnyak spaces. First, we give a criterion for the existence of radial limits for the derivatives of functions in the de Branges–Rovnyak spaces. This criterion generalizes a result of Ahern–Clark. Then we prove that the continuity of all functions in a de Branges–Rovnyak space on an open arc I of the boundary is enough to ensure the analyticity of these functions on I. We use this property in a question related to Bernstein’s inequality. Received: May 10, 2007. Revised: August 8, 2007. Accepted: August 8, 2007.     

Vanadium–Schiff base complex-functionalized SBA-15 as a heterogeneous catalyst: synthesis,characterization and application in pharmaceutical sulfoxidation of sulfids

Research on Chemical Intermediates - VO2(picolinichydrazone) complex as a catalyst was stabilized on a SBA-15 mesoporous silica as a catalytic support by using (3-chloropropyl)triethoxysilane as a...     

Design and optimization of nano-antenna for thermal ablation of liver cancer cells

One method of cancer therapy is to utilize nano-antenna for thermal ablation.In this method,the electromagnetic waves emitted from the nano-antenna are absorbed by the tissue and lead to heating of cancer cells.If temperature of cancer cells reaches a threshold,they will begin to die.For this purpose,an L-shaped frame nano-antenna(LSFNA) is designed to introduce into the biological tissue.Thus,the radiation characteristics of the LSFNA such as near and far-field intensities,directivity,and sensitivity to its gap width are studied to the optimization of the nano-antenna.The bio-heat and Maxwell equations are solved using the finite element method.To prevent damage to healthy tissues in this method,the antenna radiation must be completely controlled and performed carefully.Thus,penetration depth,special absorption rate,temperature distribution,and the fraction of tissue necrosis are analyzed in the biological tissue.That is why the design and optimization of the nano-antennas as a radiation source is important.Also,a pulsed source is used to excite the LSFNA.Furthermore,focusing and efficiency of the nano-antenna radiation on the cancer cell is tuned using an adjustable liquid crystal lens.The focus of this lens is changing under an electric field applied to its surrounding cathode.