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排序方式: 共有385条查询结果,搜索用时 15 毫秒
31.
Bistri O Mazeau K Auzély-Velty R Sollogoub M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(31):8847-8857
New beta-cyclodextrin (beta-CD) dimeric species have been synthesised in which the two CD moieties are connected by one or two hydrophilic oligo(ethylene oxide) spacers. Their complexation with sodium adamantylacetate (free adamantane) and adamantane-grafted chitosan (AD-chitosan) was then studied by different complementary techniques and compared with their hydrophobic counterparts that contain an octamethylene spacer. Isothermal titration calorimetry experiments have demonstrated that the use of hydrophilic spacers between the two CDs instead of aliphatic chains makes almost all of the CD cavities available for the inclusion of free adamantane. Investigation of the interaction of the CDs with AD-chitosan by viscosity measurements strongly suggests that the molecular conformation of the CD dimeric species plays a crucial role in their cross-linking with the biopolymer. The derivative doubly linked with hydrophilic arms, also called a duplex, has been shown to be a more efficient cross-linking agent than its singly bridged counterpart, referred to as a dimer. Hence, only 0.5 molar equivalents of the hydrophilic duplex with respect to adamantane was required to obtain the maximum viscosity, whereas in the case of the duplex with aliphatic spacers, the maximum viscosity was achieved with a [duplex]/[AD] ratio of about 1.7 (corresponding to a [CD]/[AD] ratio of 2.5), but with a higher value. To clarify the relationships between the molecular architecture and complexation properties, computational studies were also performed that clearly confirmed the importance of double bridging. 相似文献
32.
The first member of a new class of ditopic calix[6]arene has been synthesized, which is decorated with three N-methylimidazoles at the small rim and three 1,4-disubstituted-1,2,3-triazoles at the large rim. The coordination of a first Zn(II) cation selectively takes place at the small rim. Addition of a second equivalent results in the complexation of the three triazoles, providing a rare example of 1,2,3-triazole ligands embedded within a supramolecular system. 相似文献
33.
Effectiveness of Photodynamic Therapy in Elimination of HPV‐16 and HPV‐18 Associated with CIN I in Mexican Women 下载免费PDF全文
Elizabeth Maldonado Alvarado Martha Olivia Osorio Peralta Alejandra Moreno Vázquez Lydia Alejandra Martínez Guzmán Maria Eugenia Melo Petrone Zulma Iveth Enriquez Mar Dora Estela Jovel Galdamez Bárbara Carrión Solana Guadalupe Balderas Martínez Eduarda Parra Rossana Inés Castellanos Oliveros Rosa Linda Bello Leiva Araceli Espinosa Montesinos Citlalli Barrera Mendoza Selma Eugenia Medina García Eva Ramón Gallegos 《Photochemistry and photobiology》2017,93(5):1269-1275
This study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ‐aminolevulinic acid (5‐ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5‐ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J cm?2 at 635 nm. This procedure was performed three times at 48‐h intervals. Clinical follow‐up was performed at 3, 6, and 12 months after the initial PDT administration, by colposcopy, cervical cytology, histopathological analysis, polymerase chain reaction, and hybrid capture. Of HPV‐infected patients without evidence of CIN I, 80% cleared the infection, while HPV associated with CIN I was eliminated in 83% of patients (P < 0.05). At 12 months, CIN I had regressed in 57% of patients, although this response was not statistically significant. PDT using 6% 5‐ALA is concluded to be effective in eliminating HPV infection associated or not with CIN I. 相似文献
34.
Jean Claude Didelot Tomani Olivier Bonnet Alain Nyirimigabo William Deschamps Alembert Tiabou Tchinda Olivia Jansen Allison Ledoux Marie Jeanne Mukazayire Luc Vanhamme Michel Frdrich Raymond Muganga Jacob Souopgui 《Molecules (Basel, Switzerland)》2021,26(9)
Malaria remains one of the leading causes of death in sub-Saharan Africa, ranked in the top three infectious diseases in the world. Plants of the Eriosema genus have been reported to be used for the treatment of this disease, but scientific evidence is still missing for some of them. In the present study, the in vitro antiplasmodial activity of the crude extract and compounds from Eriosema montanum Baker f. roots were tested against the 3D7 strain of Plasmodium falciparum and revealed using the SYBR Green, a DNA intercalating compound. The cytotoxicity effect of the compounds on a human cancer cell line (THP-1) was assessed to determine their selectivity index. It was found that the crude extract of the plant displayed a significant antiplasmodial activity with an IC50 (µg/mL) = 17.68 ± 4.030 and a cytotoxic activity with a CC50 (µg/mL) = 101.5 ± 12.6, corresponding to a selective antiplasmodial activity of 5.7. Bioactivity-guided isolation of the major compounds of the roots’ crude extract afforded seven compounds, including genistein, genistin and eucomic acid. Under our experimental conditions, using Artemisinin as a positive control, eucomic acid showed the best inhibitory activity against the P. falciparum 3D7, a well-known chloroquine-sensitive strain. The present results provide a referential basis to support the traditional use of Eriosema species in the treatment of malaria. 相似文献
35.
Rosana A. Gonalves Rosimara P. Toledo Nirav Joshi Olivia M. Berengue 《Molecules (Basel, Switzerland)》2021,26(8)
Over the last two decades, oxide nanostructures have been continuously evaluated and used in many technological applications. The advancement of the controlled synthesis approach to design desired morphology is a fundamental key to the discipline of material science and nanotechnology. These nanostructures can be prepared via different physical and chemical methods; however, a green and ecofriendly synthesis approach is a promising way to produce these nanostructures with desired properties with less risk of hazardous chemicals. In this regard, ZnO and TiO2 nanostructures are prominent candidates for various applications. Moreover, they are more efficient, non-toxic, and cost-effective. This review mainly focuses on the recent state-of-the-art advancements in the green synthesis approach for ZnO and TiO2 nanostructures and their applications. The first section summarizes the green synthesis approach to synthesize ZnO and TiO2 nanostructures via different routes such as solvothermal, hydrothermal, co-precipitation, and sol-gel using biological systems that are based on the principles of green chemistry. The second section demonstrates the application of ZnO and TiO2 nanostructures. The review also discusses the problems and future perspectives of green synthesis methods and the related issues posed and overlooked by the scientific community on the green approach to nanostructure oxides. 相似文献
36.
Yao Jin Friederike Adams Judith Möller Lorenz Isert Christoph M. Zimmermann David Keul Olivia M. Merkel 《Macromolecular bioscience》2023,23(2):2200409
Polyethylenimine (PEI) is a commonly used cationic polymer for small-interfering RNA (siRNA) delivery due to its high transfection efficiency at low commercial cost. However, high molecular weight PEI is cytotoxic and thus, its practical application is limited. In this study, different formulations of low molecular weight PEI (LMW-PEI) based copolymers polyethylenimine-g-polycaprolactone (PEI–PCL) (800 Da–40 kDa) and PEI–PCL–PEI (5–5–5 kDa) blended with or without polyethylene glycol-b-polycaprolactone (PEG–PCL) (5 kDa-4 kDa) are investigated to prepare nanoparticles via nanoprecipitation using a solvent displacement method with sizes ≈100 nm. PEG–PCL can stabilize the nanoparticles, improve their biocompatibility, and extend their circulation time in vivo. The nanoparticles composed of PEI–PCL–PEI and PEG–PCL show higher siRNA encapsulation efficiency than PEI–PCL/PEG–PCL based nanoparticles at low N/P ratios, higher cellular uptake, and a gene silencing efficiency of ≈40% as a result of the higher molecular weight PEI blocks. These results suggest that the PEI–PCL–PEI/PEG–PCL nanoparticle system could be a promising vehicle for siRNA delivery at minimal synthetic effort. 相似文献
37.
Constantin Bu?e Dhaou Lassoued Thanh Lan Nguyen Olivia Saierli 《Integral Equations and Operator Theory》2012,74(3):345-362
Let u μ, x, s (., 0) be the solution of the following well-posed inhomogeneous Cauchy Problem on a complex Banach space X $$\left \{\begin{array}{ll}\dot{u}(t) = A(t)u(t) + e^{i\mu t}x, \quad t > s \\ u(s) = 0. \end{array} \right.$$ Here, x is a vector in X,?μ is a real number, q is a positive real number and A(·) is a q-periodic linear operator valued function. Under some natural assumptions on the evolution family ${\mathcal{U} = \{U(t, s): t \geq s\}}$ generated by the family {A(t)}, we prove that if for each?μ, each s?≥ 0 and every x the solution u μ, x, s (·, 0) is bounded on R + by a positive constant, depending only on x, then the family ${\mathcal{U}}$ is uniformly exponentially stable. The approach is based on the theory of evolution semigroups. 相似文献
38.
39.
Let \(\mathcal {U}=\{U(t,s)\}_{t\ge s\ge 0}\) be a strongly continuous and exponentially bounded evolution family acting on a complex Banach space X and let \(\mathcal {X}\) be a certain Banach function space of X-valued functions. We prove that the growth bound of the family \(\mathcal {U}\) is less than or equal to \(-\frac{1}{c(\mathcal {U}, \mathcal {X})}\) provided that the convolution operator \(f\mapsto \mathcal {U}*f\) acts on \(\mathcal {X}.\) It is well known that under the latter assumption, the convolution operator is bounded and then \(c(\mathcal {U}, \mathcal {X})\) denotes (ad-hoc) its norm in \(\mathcal {L}(\mathcal {X}).\) As a consequence, we prove that if \(\sup \nolimits _{s\ge 0}\int \nolimits _{s}^\infty \Vert U(t,s)\Vert dt=u_1(\mathcal {U})<\infty ,\) then \(\omega _0(\mathcal {U})u_1(\mathcal {U})\le -1.\) Finally, we give an example showing that the accuracy of the estimates may be quite accurate. 相似文献
40.