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41.
Breast cancer research has developed rapidly in the past few decades, leading to longer survival times for patients and opening up the possibility of developing curative treatments for advanced breast cancer. Our increasing knowledge of the biological pathways associated with the progression and development of breast cancer, alongside the failure of conventional treatments, has prompted us to explore gene therapy as an alternative therapeutic strategy. We previously reported that gef gene from E. coli has shown considerable cytotoxic effects in breast cancer cells. However, its action mechanism has not been elucidated. Indirect immunofluorescence technique using flow cytometry and immunocytochemical analysis were used to detect breast cancer markers: estrogen (ER) and progesterone (PR) hormonal receptors, human epidermal growth factor receptor-2 proto-oncogene (c-erbB-2), ki-67 antigen and p53 protein. gef gene induces an increase in ER and PR expressions and a decrease in ki-67 and c-erbB-2 gene expressions, indicating a better prognosis and response to treatment and a longer disease-free interval and survival. It also increased p53 expression, suggesting that gef-induced apoptosis is regulated by a p53-mediated signaling pathway. These findings support the hypothesis that the gef gene offers a new approach to gene therapy in breast cancer.  相似文献   
42.
This article explores the use of computational fluid dynamics (CFD) modelling for designing an oven which enables the adiabatic operation of a chemical reactor at bench-scale. For accomplishing this scope, the oven consists of electrical heating elements, air circulation system and a control loop that uses the temperature inside the reactor as set-point for the reactor wall temperature. Depending on the spatial configuration of the air flow and the heating elements, as well as the air flow rate, different temperature profiles within a given oven section are obtained, being appropriate those leading to uniform reactor wall temperatures and fast dynamic response. The use of CFD allows, by obtaining temperature maps within the oven, the selection of appropriate configurations. The optimal configuration adopted has been experimentally validated in a lab-scale adiabatic reactor working with both particulated and monolithic catalyst beds.  相似文献   
43.
44.
Because of advantageous features such as shorter reaction times, greater yields, limited generation of by‐products and relatively easy and straightforward scale‐up, microwave‐assisted synthesis has become a very appealing tool in organic synthesis. Conversely, its implementation in the context of the synthesis of biomaterials for biopharmaceutical applications has been more limited. The present work reports on the fast and efficient microwave‐assisted synthesis of poly(ethylene glycol) (PEG)‐initiated poly(ε‐caprolactone) diols (PCL) by the ring‐opening polymerization (ROP) of ε‐caprolactone using stannous octanoate as catalyst. Since the PEG content in the synthesized copolymers was extremely low (0.2–1.9%), products were highly hydrophobic and displayed the intrinsic thermal properties of pure PCL. As opposed to the more time‐consuming conventional thermally‐driven synthesis that usually demands 2–3 h, the microwave technique resulted in intermediate to high molecular weight PEG‐PCL derivatives within 10–15 min. The influence of different parameters affecting the synthetic process, namely monomer‐to‐initiator ratio, reaction time, catalyst concentration and the presence, type, and concentration of solvent were thoroughly investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   
45.
In order to find the best combination of three synthetic rubbers, that is, styrene‐butadiene rubber (SBR) grade 1712, SBR grade 1721 and high‐1,4‐cis polybutadiene, that produce a compound with specific end‐use properties, a statistical experimental design is proposed in this work. The design consists of ten mixtures containing specific amounts of total styrene and BR content. A number of properties are tested in each mixture, selecting those related to requirements for the tread of a high performance tire: glass transition temperature (Tg), the ratio between the viscous modulus and the elastic modulus (tanδ@60 °C), Mooney viscosity, and the tensile properties. The values obtained for each property are fit to statistically significant models, obtaining the respective response surfaces. These are next used to define a desirable formulation with the optimal ratio of each rubber, and finally the optimized formulation is validated by comparing the experimental and predicted values for each modeled property. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46548.  相似文献   
46.
This review article describes recent results obtained in the self-assembly of supramolecular capsules derived from calixpyrrole components. Due to their ease of synthesis, calix[4]pyrroles are by far the most typically used units in these systems. A clear conformational and structural analogy exists between calix[4]arenes and calix[4]pyrroles. However, to date, the number of examples in the literature that use calix[4]pyrrole scaffolds instead of calix[4]arenes for the construction of supramolecular capsules is still meager. Four different approaches are considered for the use of calix[4]pyrrole derivatives in the assembly of molecular capsules. Firstly, in an analogous manner to resorcin[4]arenes and pyrogallol[4]arenes, aryl-extended calix[4]pyrroles with hydroxyl groups in their upper rim self-assemble through direct or mediated rim-to-rim interactions into capsular aggregates. Secondly, aryl-extended calix[4]pyrroles having non-complementary hydrogen-bonding groups in their upper rim form dimeric templated capsules with suitable substrates. Thirdly, the elaboration of the upper rim of the calix[4]pyrroles with urea groups affords dimeric capsules with polar functionalized interiors that closely resemble their tetraurea calix[4]arene analogs. Finally, the chemical modification of the pyrrole units of octamethyl calix[4]pyrrole into tetrathiafulvalene derivatives yields dimeric capsules induced by anion coordination that display interesting properties in the binding of electron-poor guests.  相似文献   
47.
In this article we use fluorescence resonance energy transfer (FRET) to investigate how a classic coalescing aid, such as 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (Texanol?) (TX), acts on the earliest stages of polymer diffusion as the latex film is still drying. In our approach, we temporarily arrest the drying process of a partially wet latex film by sealing it in an airtight chamber previously cooled to near the latex Tg. At these conditions, we are able to effectively stop the drying process and the polymer diffusion. FRET measurements at various locations on such a sample provide us information about the mechanism operating at the initial stages of polymer diffusion as the latex film is still drying. We complete our study with FRET measurements carried out at longer aging times on predried latex films. We analyze our diffusion data in terms of free volume theory and propose a mechanism that can account for the results obtained.  相似文献   
48.
Thin multilayer coatings of ZrO2–Y2O3–Al2O3 were prepared using the sol-gel method and dip-coating technique in order to advance in the study of what influence the incorporation of Al2O3 has on films of Y2O3-doped ZrO2, investigating its role in the synthesis of the solutions and in the characteristics and properties of the coatings. After the characterization of the solutions used in the process, the microstructure of the films was studied and their mechanical behaviour and resistance to thermal shock were determined so as to optimize the characteristics and functionality of these coatings. With increased alumina content, 3YSZ-Al2O3 (20 mol%), the cubic phase of the zirconia disappeared completely at the sintering temperature used (700 °C), resulting in the tetragonal phase with Al in solution. There was also a decrease in the coatings' hardness and Young's modulus, and an increase in toughness and resistance to thermal shock. These results allow guidelines to be established for the design of multilayer structures that are, tougher, more resistant, and have improved surface properties.  相似文献   
49.
The pretreatment process to disintegrate lignocellulose and to fractionate its three main components hemicellulose, cellulose, and lignin, is a crucial step to enable sustainable and economic value chains based on biomass feedstock. This review provides an overview of the recent patenting activities on pretreatment. Most of these activities focus on optimization of different known processes to improve economics, such as increased catalyst efficiency, effluents recirculation, or lignin valorization. However, also a number of patents and demonstration activities based on emerging concepts for pretreatments are observed.  相似文献   
50.
Polymeric micelles can be designed and synthesized to bear polymeric blocks with different hydrophilicities; this triggers their self‐assembly into micellar aggregates similar to those generated with traditional surfactants. The basic structure consists of a hydrophobic core, capable of containing guest substances, and a hydrophilic shell, which stabilizes the payload and protects it from external degradation or prevents its quick elimination from the body. The accumulation of block copolymer micelles (BCMs) in a target cell or tissue can be accomplished by two main mechanisms, passive and active targeting; this allows the payload release at the site of action when desired. Hence, in this general overview, we pay special attention to newly developed single‐stimulus‐ and multi‐stimuli‐responsive delivery systems capable of disassembling and reassembling (in some cases) as a response to changes in their physicochemical properties. Also, special interest is also devoted to multifunctional BCMs incorporating multiple therapeutic agents and/or multiple imaging contrast agents, which can be considered the new generation (third generation) of drug‐delivery systems, that is, nanotheranostic platforms. Finally, a summary of BCM‐based drug‐delivery systems currently under clinical trials is given. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42650.  相似文献   
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