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441.
《Arabian Journal of Chemistry》2023,16(3):104532
Oily sewage poses a serious environmental risk normally; thus, herein, the modified guar gum (GG-SH) was prepared through rapid condensation reaction between polysaccharide and stearic hydrazide. GG-SH exhibited high removal efficiency of crude oil, the maximum adsorption capacity was calculated to be 2157.3 mg?g-1. The kinetics and isotherm statistical theories showed that the sorption of crude oil onto GG-SH was governed by pseudo-second-order, and Langmuir models, respectively. The removal rate was still high after six cycles of regeneration, indicating an outstanding technique to prepare polysaccharide-based material for the oily sewage treatment with high efficiency and recyclability. 相似文献
442.
《印度化学会志》2023,100(2):100899
pH shifting effect on the adsorption of anionic RBB dye was tested by using untreated and CTAB-treated SBP as adsorbent in both batch and continuous systems. Characterization of the sorbents revealed the effects of surface modification. Enhanced binding sites and more porous surface structure resulted in improved adsorption capability. Flow rate and initial RBB concentration effects were tested in packed bed column. Optimum pH value of the adsorption, which was determined as 2.0 in the batch studies with untreated SBP, shifted to 8.0 with 20 g/L CTAB treated SBP. Experimental data in column studies showed the decreasing capacity with increasing flow rate and enhanced performance with increasing inlet RBB concentration for both sorbents. Maximum capacities of the columns were found as 36.9 and 2.6 mg/g with dried SBP at pH 2.0 and 8.0, respectively, at a maximum inlet RBB concentration of 500 mg/L and a minimum flow rate of 0.8 mL/min. The highest capacity value at pH 8.0 was found as 140.0 mg/g under the same operating conditions, which reveals positive effect of the treatment on adsorptive performance. Langmuir isotherm was found to be most convenient model for the all equilibrium cases in the column. Moreover, Thomas model accurately predicted the breakthrough curves of each system. This is the first study reporting the modeling data of an anionic dye adsorption in a packed bed column by using modified SBP. 相似文献
443.
Yali Feng Jing Fang Yan Zhao Shuyue Ye Anna Wang Yuqi Zhang Jinfeng Zhu Jiachen Li Zhengzhong Lv Zhongsheng Zhao Prof. Haibin Shi 《Angewandte Chemie (International ed. in English)》2023,62(19):e202218969
Mitochondrial RNA (mtRNA) plays a critical role in synthesis of mitochondrial proteins. Interfering mtRNA is a highly effective way to induce cell apoptosis. Herein, we report a near-infrared (NIR) light-mediated mitochondrial RNA modification approach for long-term imaging and effective suppression of tumors. A tumor-targetable NIR fluorescent probe f-CRI consisting of a cyclic RGD peptide, a NIR fluorophore IR780, and a singlet oxygen (1O2)-labile furan group for RNA modification was rationally designed and synthesized. This probe was demonstrated to dominantly accumulate in cellular mitochondria and could be covalently conjugated onto mtRNA upon 808 nm irradiation resulting in prolonged retention in tumors. More notably, this covalent modification of mtRNA by f-CRI could perturb the function of mitochondria leading to remarkable tumor suppression. We thus envision that our current approach would offer a potential approach for cancer RNA interference therapeutics. 相似文献
444.
Dr. Zhen Yu Dr. Dale F. Kreitler Yin Ting T. Chiu Ruiwen Xu Austin T. Bruchs Dr. Craig A. Bingman Prof. Samuel H. Gellman 《Angewandte Chemie (International ed. in English)》2023,62(40):e202308100
Peptide engineering efforts have delivered drugs for diverse human diseases. Side chain alteration is among the most common approaches to designing new peptides for specific applications. The peptide backbone can be modified as well, but this strategy has received relatively little attention. Here we show that new and favorable contacts between a His side chain on a target protein and an aromatic side chain on a synthetic peptide ligand can be engineered by rational and coordinated side chain modification and backbone extension. Side chain modification alone was unsuccessful. Binding measurements, high-resolution structural studies and pharmacological outcomes all support the synergy between backbone and side chain modification in engineered ligands of the parathyroid hormone receptor-1, which is targeted by osteoporosis drugs. These results should motivate other structure-based designs featuring coordinated side chain modification and backbone extension to enhance the engagement of peptide ligands with target proteins. 相似文献
445.
Dr. Joachim F. R. Van Guyse Dr. Yann Bernhard Dr. Annelore Podevyn Prof. Dr. Richard Hoogenboom 《Angewandte Chemie (International ed. in English)》2023,62(40):e202303841
Non-activated esters are prominently featured functional groups in polymer science, as ester functional monomers display great structural diversity and excellent compatibility with a wide range of polymerization mechanisms. Yet, their direct use as a reactive handle in post-polymerization modification has been typically avoided due to their low reactivity, which impairs the quantitative conversion typically desired in post-polymerization modification reactions. While activated ester approaches are a well-established alternative, the modification of non-activated esters remains a synthetic and economically valuable opportunity. In this review, we discuss past and recent efforts in the utilization of non-activated ester groups as a reactive handle to facilitate transesterification and aminolysis/amidation reactions, and the potential of the developed methodologies in the context of macromolecular engineering. 相似文献
446.
Shuyu Liang Jiewen Xiao Tianyu Zhang Yue Zheng Qiang Wang Bin Liu 《Angewandte Chemie (International ed. in English)》2023,62(44):e202310740
Electrochemical CO2 reduction to value-added chemicals or fuels offers a promising approach to reduce carbon emissions and alleviate energy shortage. Cu-based electrocatalysts have been widely reported as capable of reducing CO2 to produce a variety of multicarbon products (e.g., ethylene and ethanol). In this work, we develop sulfur-doped Cu2O electrocatalysts, which instead can electrochemically reduce CO2 to almost exclusively formate. We show that a dynamic equilibrium of S exists at the Cu2O-electrolyte interface, and S-doped Cu2O undergoes in situ surface reconstruction to generate active S-adsorbed metallic Cu sites during the CO2 reduction reaction (CO2RR). Density functional theory (DFT) calculations together with in situ infrared absorption spectroscopy measurements show that the S-adsorbed metallic Cu surface can not only promote the formation of the *OCHO intermediate but also greatly suppress *H and *COOH adsorption, thus facilitating CO2-to-formate conversion during the electrochemical CO2RR. 相似文献
447.
Brigita Tomšič Barbara Simončič Boris Orel Lidija Černe Petra Forte Tavčer Mateja Zorko Ivan Jerman Aljaž Vilčnik Janez Kovač 《Journal of Sol-Gel Science and Technology》2008,47(1):44-57
Multifunctional, water and oil repellent and antimicrobial finishes for cotton fibres were prepared from a commercially available
fluoroalkylfunctional water-born siloxane (FAS) (Degussa), nanosized silver (Ag) (CHT) and a reactive organic–inorganic binder
(RB) (CHT). Two different application procedures were used: firstly, one stage treatment of cotton fabric samples by FAS sol
(i), as well as by a sol mixture constituted from all three precursors (Ag–RB–FAS, procedure 1S) (ii), and secondly, two stage
treatment of cotton by Ag–RB sol and than by FAS sol (Ag–RB + FAS, procedure 2S) (iii). The hydrophobic and oleophobic properties
of cotton fabrics treated by procedures (i)–(iii) before and after consecutive (up to 10) washings were established from contact
angle measurements (water, diiodomethane and n-hexadecane) and correlated with infrared and XPS spectroscopic measurements. The results revealed that even after 10 washing
cycles cotton treated with Ag–RB + FAS (2S) retained an oleophobicity similar to that of the FAS treated cotton, while the
Ag–RB–FAS (1S) cotton fibres exhibited a loss of oleophobicity already after the second washing, even though fluorine and
C–F vibrational bands were detected in the corresponding XPS and IR spectra. The antibacterial activity of cotton treated
by procedures (i)–(iii) was tested by its reduction of the bacteria Escherichia coli and Staphylococcus aureus following the AATCC 100-1999 standard method and EN ISO 20743:2007 transfer method. The reduction in growth of both bacteria
was nearly complete for the unwashed Ag–RB and Ag–RB–FAS (S1), but for the unwashed Ag–RB + FAS (S2) treated cotton no reduction
of S. aureus and 43.5 ± 6.9% reduction of E. coli was noted. After the first washing, the latter two finishes exhibited nearly a complete reduction of E. coli but for the Ag–RB treated cotton the reduction dropped to 88.9 ± 3.4. None of the finishes retained antibacterial properties
after 10 repetitive washings. The beneficial and long-lasting low surface energy effect of FAS finishes in the absence of
Ag nanoparticles, which led to the “passive” antibacterial properties of FAS treated cotton fabrics, was established by applying
the EN ISO 20743:2007 transfer method. The results revealed a reduction in bacteria of about 21.9 ± 5.7% (FAS), 13.1 ± 4.8%
(Ag–RB–FAS (S1)) and 41.5 ± 3.7% (Ag–Rb + FAS (S2)), while no reduction of the growth of bacteria was observed for cotton
treated with Ag nanoparticles after 10 repetitive washings. The physical properties (bending rigidity, breaking strength,
air permeability) of finished cotton samples were determined, and showed increased fabric softness and flexibility as compared
to the Ag–RB treated cotton, but a slight decrease of breaking strength in the warp and weft directions, while air permeability
decreased for all type of finishes. 相似文献
448.
使用浓HNO3和浓H2O2对活性炭进行常温氧化改性,用FTIR和N2吸附法对活性炭进行表面分析,用AAS、SEM、XRD研究银在活性炭表面的吸附和分布特征,并研究了载银活性炭的抗茵性能.结果表明,活性炭经浓HNO3常温改性后,比表面积提高,而经浓H2O2常温改性后,比表面积略有下降,但都使活性炭表面含氧基团增加.改性后,活性炭表面增加的含氧基团为[Ag(NH3)2] 的还原吸附提供更多的活性点,使银的吸附量增大5倍多,银颗粒更加密集,大小更加均一.研究表明,载银活性炭具有明显的抗茵作用,其中对金黄色葡萄球菌的杀灭效果优于对大肠杆菌的杀灭效果,氧化改性使载银活性炭抗茵作用显著增强,其中硝酸改性现象更加明显. 相似文献
449.
Zhao Jin~a Da Ling Yang~ 《中国化学快报》2008,19(3):367-370
New hydrophobic poly(phthalazinone ether sulfone ketone) (PPESK) hollow fiber composite membranes were obtained by surface-coated modification method. 相似文献
450.
Organic framework materials have shown increasingly promising applications in biomedicine, such as drug delivery and release. In this work, we first synthesized a new hydroxyl-containing imine-linked two-dimensional covalent organic framework (COF) through solvothermal synthesis. Then, the imine group was converted into a benzoxazine group using a cyclization reaction. The results show that the postsynthetic modification did not change the basic framework of the original COF and did not affect the basic properties of the original COF. At the same time, the new benzoxazine group obtained by cyclization gave the COF good antibacterial activity against Escherichia coli and Staphylococcus aureus. The COF efficiency after cyclization was improved, and its antibacterial activity against both bacteria was over 90% compared with the imine-linked COF. Moreover, the benzoxazine-linked COF crystal structure and pore structures were retained, leaving the drug delivery and release functions unaffected. A benzoxazine-linked COF has never been reported because it cannot be synthesized by a direct reaction method. The work in this paper shows that the COFs that cannot be directly synthesized can be obtained through specific postsynthetic modification reactions. This means that more functional COFs can be obtained based on existing COFs, and the diversity of COF types and their potential applications can be further enriched and expanded. 相似文献