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991.
Raymundo Cea-Olivares Omar Jimnez-Sandoval Simn Hernndez-Ortega Mnica Snchez Rubn Alfredo Toscano Ionel Haiduc 《Heteroatom Chemistry》1995,6(1):89-97
The crystal and molecular structures of both neutral and anionic 1-methyl-1H-tetrazole-5-thiol, as its potassium(18-crown-6) salt, are reported. In the solid state, the molecular thiotetrazole adopts a planar, dimeric arrangement, in which two neighboring molecules are hydrogen bridged. Each monomeric unit exhibits considerable π electron delocalization over the CN2S fragment. The anionic form displays extensive, but not uniform, π electron delocalization within the ring, which also extends to the exocyclic carbon–sulfur bond, the structure being best described as a hybrid. The potassium cation is coordinated to the macrocyclic 18-crown-6 ether as expected, but it also interacts with the NCS fragment of the tetrazolethiolate ring. 相似文献
992.
Hanaa S. Omar Soheir N. Abd El-Rahman Sheikha M. AlGhannam Nour El-Houda A. Reyad Mohamed S. Sedeek 《Molecules (Basel, Switzerland)》2021,26(20)
Background: The present study investigated the antifungal activity and mode of action of four Olea europaea leaf extracts, Thymus vulgaris essential oil (EO), and Boswellia carteri EO against Fusarium oxysporum. Methods: Fusarium oxysporum lactucae was detected with the internal transcribed spacer (ITS) region. The chemical compositions of chloroform and dichloromethane extracts of O. europaea leaves and T. vulgaris EO were analyzed using GC-MS analysis. In addition, a molecular docking analysis was used to identify the expected ligands of these extracts against eleven F. oxysporum proteins. Results: The nucleotide sequence of the F. oxysporum lactucae isolate was deposited in GenBank with Accession No. . The T. vulgaris EO, chloroform, dichloromethane and ethanol efficiently inhibited the growth at concentrations of 75.5 and 37.75 mg/mL, whereas ethyl acetate, and B. carteri EO did not exhibit antifungal activity. The GC-MS analysis revealed that the major and most vital compounds of the T. vulgaris EO, chloroform, and dichloromethane were thymol, carvacrol, tetratriacontane, and palmitic acid. Moreover, molecular modeling revealed the activity of these compounds against F. oxysporum. Conclusions: Chloroform, dichloromethane and ethanol, olive leaf extract, and T. vulgaris EO showed a strong effect against F. oxysporum. Consequently, this represents an appropriate natural source of biological compounds for use in healthcare. In addition, homology modeling and docking analysis are the best analyses for clarifying the mechanisms of antifungal activity. MT249304.1相似文献
993.
Daopeng Sheng Lin Zhu Xing Dai Chao Xu Peng Li Carolyn I. Pearce Chengliang Xiao Jing Chen Ruhong Zhou Tao Duan Omar K. Farha Zhifang Chai Shuao Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):5022-5026
99Tc contamination at legacy nuclear sites is a serious and unsolved environmental issue. The selective remediation of 99TcO4? in the presence of a large excess of NO3? and SO42? from natural waste systems represents a significant scientific and technical challenge, since anions with a higher charge density are often preferentially sorbed by traditional anion‐exchange materials. We present a solution to this challenge based on a stable cationic metal‐organic framework, SCU‐102 (Ni2(tipm)3(NO3)4), which exhibits fast sorption kinetics, a large capacity (291 mg g?1), a high distribution coefficient, and, most importantly, a record‐high TcO4? uptake selectivity. This material can almost quantitatively remove TcO4? in the presence of a large excess of NO3? and SO42?. Decontamination experiments confirm that SCU‐102 represents the optimal Tc scavenger with the highest reported clean‐up efficiency, while first‐principle simulations reveal that the origin of the selectivity is the recognition of TcO4? by the hydrophobic pockets of the structure. 相似文献
994.
Jun Pan Xiyan Li Xiwen Gong Jun Yin Dianli Zhou Lutfan Sinatra Renwu Huang Jiakai Liu Jie Chen Ibrahim Dursun Ahmed M. El‐Zohry Makhsud I. Saidaminov Hong‐Tao Sun Omar F. Mohammed Changhui Ye Edward H. Sargent Osman M. Bakr 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(45):16223-16227
Interest has been growing in defects of halide perovskites in view of their intimate connection with key material optoelectronic properties. In perovskite quantum dots (PQDs), the influence of defects is even more apparent than in their bulk counterparts. By combining experiment and theory, we report herein a halide‐vacancy‐driven, ligand‐directed self‐assembly process of CsPbBr3 PQDs. With the assistance of oleic acid and didodecyldimethylammonium sulfide, surface‐Br‐vacancy‐rich CsPbBr3 PQDs self‐assemble into nanowires (NWs) that are 20–60 nm in width and several millimeters in length. The NWs exhibit a sharp photoluminescence profile (≈18 nm full‐width at‐half‐maximum) that peaks at 525 nm. Our findings provide insight into the defect‐correlated dynamics of PQDs and defect‐assisted fabrication of perovskite materials and devices. 相似文献
995.
996.
Dr. Santiago E. Herrera Dr. Maximiliano L. Agazzi Dr. M. Lorena Cortez Dr. Waldemar A. Marmisollé Dr. Mario Tagliazucchi Dr. Omar Azzaroni 《Chemphyschem》2019,20(8):1044-1053
Ionically crosslinked poly(allylamine)/phosphate (PAH/Pi) colloids consist of self-assembled nanostructures stabilized by supramolecular interactions. Under physiological conditions, these interactions should be present at high ionic strength and only in a narrow pH window to be effective as drug delivery agents. In this work we study the effect of the pH and ionic strength in the chemical behaviour of inorganic phosphate (Pi), poly(allylamine hydrochloride) (PAH) and their mixture in aqueous solution (PAH−Pi). By combination of experimental measurements and a theoretical model, we demonstrate that the driving force that leads to the formation of colloids is the electrostatic pairing between the positively charged amino groups in PAH and negatively charged HPO42− ions. Increasing the ionic strength of the system by addition of KCl weakens the PAH−Pi interactions and narrows the pH stability window from 4 to 1.8 pH units. In addition, a fully reversible system was obtained in which the colloids assemble and disassemble by changing the pH between 6.8 and 7.1 at high ionic strength, making them suitable for use as pH-responsive nanocarriers. 相似文献
997.
Seema Hassan Satti Naveed Iqbal Raja Muhammad Ikram Hesham F. Oraby Zia-Ur-Rehman Mashwani Azza H. Mohamed Ajit Singh Ahmad A. Omar 《Molecules (Basel, Switzerland)》2022,27(13)
In this study, we evaluated bioinspired titanium dioxide nanoparticles (TiO2 NPs) that elicited biochemical and proteome modifications in wheat plants under the biotic stress caused by Puccinia striiformis f. sp. tritici (Pst). Biosynthesis of TiO2 NPs was confirmed using UV–Vis spectrophotometry, energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. We found that the nanoparticles with crystalline nature were smaller than 100 nm. The results of FTIR analysis showed the presence of potential functional groups exhibiting O-H, N-H, C-C, and Ti-O stretching. The TiO2 NPs of different concentrations (20, 40, 60, and 80 mg L−1) were exogenously applied to wheat plants under the biotic stress caused by Pst, which is responsible for yellow stripe rust disease. The results of the assessment of disease incidence and percent disease index displayed time- and dose-dependent responses. The 40 mg L−1 TiO2 NPs were the most effective in decreasing disease severity. The bioinspired TiO2 NPs were also evaluated for enzymatic (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), and nonenzymatic metabolites (total proline, phenolic, and flavonoid contents) in wheat plants under stripe rust stress. The 40 mg L−1 TiO2 NPs were effective in eliciting biochemical modifications to reduce biotic stress. We further evaluated the effects of TiO2 NPs through gel- and label-free liquid chromatography-mass spectrometry (LC-MS) proteome analysis. We performed proteome analysis of infected wheat leaves and leaves treated with 40 mg L−1 TiO2 NPs under stripe rust stress. The functional classification of the proteins showed downregulation of proteins related to protein and carbohydrate metabolism, as well as of photosynthesis in plants under biotic stress. An upregulation of stress-related proteins was observed, including the defense mechanisms and primary metabolic pathways in plants treated with 40 mg L−1 TiO2 NPs under stress. The experimental results showed the potential of applying biogenic TiO2 NPs to combat fungal diseases of wheat plants and provided insight into the protein expression of plants in response to biotic stress. 相似文献
998.
999.
The ac and dc conductivities, dielectric constant and dielectric loss of a series of calcium borate glasses containing Fe2O3 up to 10 mol% were measured as a function of temperature (300–700 K) and frequency (102–105 c/s). Glasses melted in platinum crucibles were found to show slightly higher dielectric constants and conductivities than glasses melted in zirconia crucibles under the same melting conditions. Relaxation effects with a distribution of relaxation times were observed for all the glasses of this system. The data show that the pre-exponential factor τ0 is about 10?11 s. Peaks in tan δ were found to shift to higher temperatures when the frequency of measurements was increased. Activation energy for dc conduction was found to be equal to that of ac conduction. No polarization effects were observed in these glasses, indicating that conduction is predominantly electronic. 相似文献
1000.
Sabrin R. M. Ibrahim Abdelsattar M. Omar Yosra A. Muhammad Ali A. Alqarni Abdullah M. Alshehri Shaimaa G. A. Mohamed Hossam M. Abdallah Mahmoud A. Elfaky Gamal A. Mohamed Jianbo Xiao 《Molecules (Basel, Switzerland)》2022,27(20)
Phenaloenones are structurally unique aromatic polyketides that have been reported in both microbial and plant sources. They possess a hydroxy perinaphthenone three-fused-ring system and exhibit diverse bioactivities, such as cytotoxic, antimicrobial, antioxidant, and anti-HIV properties, and tyrosinase, α-glucosidase, lipase, AchE (acetylcholinesterase), indoleamine 2,3-dioxygenase 1, angiotensin-I-converting enzyme, and tyrosine phosphatase inhibition. Moreover, they have a rich nucleophilic nucleus that has inspired many chemists and biologists to synthesize more of these related derivatives. The current review provides an overview of the reported phenalenones with a fungal origin, including their structures, sources, biosynthesis, and bioactivities. Moreover, more than 135 metabolites have been listed, and 71 references have been cited. SuperPred, an artificial intelligence (AI) webserver, was used to predict the potential targets for selected phenalenones. Among these targets, we chose human glucose transporter 1 (hGLUT1) for an extensive in silico study, as it shows high probability and model accuracy. Among them, aspergillussanones C (60) and G (60) possessed the highest negative docking scores of −15.082 and −14.829 kcal/mol, respectively, compared to the native inhibitor of 5RE (score: −11.206 kcal/mol). The MD (molecular dynamics) simulation revealed their stability in complexes with GLUT1 at 100 ns. The virtual screening study results open up a new therapeutic approach by using some phenalenones as hGLUT1 inhibitors, which might be a potential target for cancer therapy. 相似文献