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81.
Bromination of alkenes, alkynes, and aromatic amines has efficiently been carried out at room temperature in short reaction times using HIO3/KBr in CH2Cl2/H2O (1:1) to prepare corresponding brominated compounds in excellent yields. 相似文献
82.
Lewis Rolband Liam Yourston Morgan Chandler Damian Beasock Leyla Danai Seraphim Kozlov Nolan Marshall Oleg Shevchenko Alexey V. Krasnoslobodtsev Kirill A. Afonin 《Molecules (Basel, Switzerland)》2021,26(13)
Silver has a long history of antibacterial effectiveness. The combination of atomically precise metal nanoclusters with the field of nucleic acid nanotechnology has given rise to DNA-templated silver nanoclusters (DNA-AgNCs) which can be engineered with reproducible and unique fluorescent properties and antibacterial activity. Furthermore, cytosine-rich single-stranded DNA oligonucleotides designed to fold into hairpin structures improve the stability of AgNCs and additionally modulate their antibacterial properties and the quality of observed fluorescent signals. In this work, we characterize the sequence-specific fluorescence and composition of four representative DNA-AgNCs, compare their corresponding antibacterial effectiveness at different pH, and assess cytotoxicity to several mammalian cell lines. 相似文献
83.
84.
Jacob A. Orkwis Ann K. Wolf Syed M. Shahid Corinne Smith Leyla Esfandiari Greg M. Harris 《Macromolecular bioscience》2020,20(9)
Severe peripheral nervous system injuries currently hold limited therapeutic solutions. Existing clinical techniques such as autografts, allografts, and newer nerve guidance conduits have shown variable outcomes in functional recovery, adverse immune responses, and in some cases low or minimal availability. This can be attributed in part to the lack of chemical, physical, and electrical cues directing both nerve guidance and regeneration. To address this pressing clinical issue, electrospun nanofibers and microfibers composed of piezoelectric polyvinylidene flouride‐triflouroethylene (PVDF‐TrFE) have been introduced as an alternative template for tissue engineered biomaterials, specifically as it pertains to their relevance in soft tissue and nerve repair. Here, biocompatible scaffolds of PVDF‐TrFE are fabricated and their ability to generate an electrical response to mechanical deformations and produce a suitable regenerative microenvironment is examined. It is determined that 20% (w/v) PVDF‐TrFE in (6:4) dimethyl formamide (DMF):acetone solvent maintains a desirable piezoelectric coefficient and the proper physical and electrical characteristics for tissue regeneration. Further, it is concluded that scaffolds of varying thickness promoted the adhesion and alignment of Schwann cells and fibroblasts. This work offers a prelude to further advancements in nanofibrous technology and a promising outlook for alternative, autologous remedies to peripheral nerve damage. 相似文献
85.
Summary. In this paper, interpolatory quadrature formulas based upon the roots of unity are studied for certain weight functions.
Positivity of the coefficients in these formulas is deduced along with computable error estimations for analytic integrands.
A comparison is made with Szeg? quadrature formulas. Finally, an application to the interval [-1,1] is also carried out.
Received February 29, 2000 / Published online August 17, 2001 相似文献
86.
Murat Aydemir Akın Baysal Feyyaz Durap Bahattin Gümgüm Saim Özkar Leyla Tatar Yıldırım 《应用有机金属化学》2009,23(11):467-475
The reactions of thiophene‐2‐(N‐diphenylphosphino)methylamine, Ph2PNHCH2‐C4H3S, 1 and thiophene‐2‐[N,N‐bis(diphenylphosphino)methylamine], (Ph2P)2NCH2‐C4H3S, 2, with MCl2(cod) (M = Pd, Pt; cod = 1,5‐cyclooctadiene) or [Cu(CH3CN)4]PF6 yields the new complexes [M(Ph2PNHCH2‐C4H3S)2Cl2], M = Pd 1a, Pt 1b, [Cu(Ph2PNHCH2‐C4H3S)4]PF6, 1c, and [M(Ph2P)2NCH2‐C4H3S)Cl2], M = Pd 2a, Pt 2b, {Cu[(Ph2P)2NCH2‐C4H3S]2}PF6, 2c, respectively. The new compounds were isolated as analytically pure crystalline solids and characterized by 31P‐, 13C‐, 1H‐NMR and IR spectroscopy and elemental analysis. Furthermore, the solid‐state molecular structures of representative palladium and platinum complexes of bis(phosphine)amine, 2a and 2b, respectively, were determined using single crystal X‐ray diffraction analysis. The palladium complexes were tested as potential catalysts in the Heck and Suzuki cross‐coupling reactions. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
87.
Azizollah Habibi Leyla Mousavifar Issa Yavari Mohammad R. Yazdanbakhsh 《Monatshefte für Chemie / Chemical Monthly》2007,138(6):603-606
Summary. Alkyl isocyanides undergo a smooth reaction with alkylidene Meldrum’s acids in the presence of arylhydroxylamines to produce N
1-alkyl-2-(3,5-dioxo-2-aryltetrahydro-4-isoxazolyl)alkanamides in high yields. 相似文献
88.
Wu H Abasova L Cheregi O Deák Z Gao K Vass I 《Journal of photochemistry and photobiology. B, Biology》2011,104(1-2):320-325
By using two strains of Arthrospira (Spirulina)platensis, an economically important filamentous cyanobacterium, we compared the impairment of PSII activity and loss of D1 protein content under UV-B radiation. Our study showed that UV-B radiation induced a gradual loss of the oxygen-evolving activity to about 56% after 180 min UV-B irradiation both in strains 439 and D-0083, which have been kept under indoor and an outdoor culturing conditions, respectively for a prolonged period of time. The loss of oxygen evolution was accelerated in both strains in the presence of lincomycin, an inhibitor of protein synthesis, and the amount of D1 protein showed a decrease comparable to that of oxygen evolution during the UV-B exposure. However, the UV-B induced loss of oxygen-evolving activity and D1 protein amount was largely prevented when A. platensis cells were exposed to UV-B irradiance supplemented with visible light. Comparison of the two strains also showed a smaller extent of D1 protein synthesis dependent PSII repair in the indoor strain. Our results show that turnover of the D1 protein is an important defense mechanism to counteract the UV-B induced damage of PSII in A. platensis, and also that visible light plays an important role in maintaining the function of PSII under simultaneous exposure to UV-B and visible light. 相似文献
89.
A series of 6-thiocyanatopurine derivatives introduced with different alkyl groups in position 9 was synthesized. The structures of the synthesized compounds were evaluated via spectroscopic methods and elemental methods of analyses. All the synthesized compounds were screened for their antibacterial activities against Gram-positive and Gram-negative bacteria and for their antifungal activities against yeast strains. All the synthesized compounds showed better antibacterial activities against Gram-positive bacteria compared to Gram-negative bacteria. DNA interactions with pBR322 DNA were determined. Most of the compounds caused conformational changes in DNA. 相似文献