scholarly journals Isolation and Structure-Activity Relationship of Subergorgic Acid and Synthesis of Its Derivatives as Antifouling Agent

Marine Drugs ◽  
2019 ◽  
Vol 17 (2) ◽  
pp. 101 ◽  
Author(s):  
Jun Zhang ◽  
Wei Ling ◽  
Zhiqiang Yang ◽  
Yan Liang ◽  
Linyan Zhang ◽  
...  
Keyword(s):  
Functional Groups ◽  
Rational Design ◽  
High Efficiency ◽  
Acid Group ◽  
Essential Elements ◽  
Gorgonian Coral ◽  
Structure Activity ◽  
Methylene Chain ◽  
Subergorgic Acid ◽  
Benzyl Esters

In this study, as part of our continuous search for environmentally-friendly antifoulants from natural resources, subergorgic acid (SA) was identified from the gorgonian coral Subergorgia suberosa, demonstrating non-toxic, significant inhibitory effects (EC50 1.25 μg/mL, LC50 > 25 μg/mL) against the settlement of Balanus amphitrite. To further explore the bioactive functional groups of SA and synthesize more potent antifouling compounds based on the lead SA, the structure-activity relationships of SA were studied, followed by rational design and synthesis of two series of SA derivatives (one being benzyl esters of SA and another being SA derivatives containing methylene chains of various lengths). Our results indicated that (1) both the double bond and ketone carbonyl are essential elements responsible for the antifouling effect of SA, while the acid group is not absolutely necessary for maintaining the antifouling effect; (2) all benzyl esters of SA displayed good antifouling effects (EC50 ranged from 0.30 to 2.50 μg/mL) with the most potent compound being 5 (EC50 0.30 μg/mL, LC50 > 25 μg/mL), which was over four-fold more potent than SA; and (3) the introduction of a methylene chain into SA reduces the antifouling potency while the length of the methylene chain may differently influence the antifouling effect, depending on the functional group at the opposite site of the methylene chain. Not only has this study successfully revealed the bioactive functional groups of SA, contributing to the mechanism of SA against the settlement of B. amphitrite, but it has also resulted in the identification of a more potent compound 5, which might represent a non-toxic, high-efficiency antifoulant.

scholarly journals Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Hui-Ju Chen ◽  
Chien-Cheng Chiu ◽  
Tsui Wang ◽  
Dong-Sheng Lee ◽  
Ta-Jung Lu
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
High Efficiency ◽  
Aqueous Media ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Terminal Alkynes ◽  
Wide Range ◽  
Transfer Hydrogenation Reaction

The bis-NHC–Ag/Pd(OAc)2 catalytic system (NHC = N-heterocyclic carbene), a combination of bis-NHC–Ag complex and Pd(OAc)2, was found to be a smart catalyst in the Pd-catalyzed transfer hydrogenation of various functionalized arenes and internal/terminal alkynes. The catalytic system demonstrated high efficiency for the reduction of a wide range of various functional groups such as carbonyls, alkynes, olefins, and nitro groups in good to excellent yields and high chemoselectivity for the reduction of functional groups. In addition, the protocol was successfully exploited to stereoselectivity for the transformation of alkynes to alkenes in aqueous media under air. This methodology successfully provided an alternative useful protocol for reducing various functional groups and a simple operational protocol for transfer hydrogenation.

Nucleoside Transporter-guided Cytarabine Conjugated Liposomes for Intracellular Methotrexate Delivery and Cooperative Choriocarcinoma Therapy

2021 ◽  
Author(s):  
Weidong Fei ◽  
Yunchun Zhao ◽  
Xiaodong Wu ◽  
Dongli Sun ◽  
Yao Yao ◽  
...  
Keyword(s):  
Targeted Delivery ◽  
Rational Design ◽  
High Efficiency ◽  
Nucleoside Transporter ◽  
Childbearing Age ◽  
Equilibrative Nucleoside Transporter ◽  
Choriocarcinoma Cells ◽  
Tumor Accumulation ◽  
Novel Strategy ◽  
Distribution Studies

Abstract The gestational trophoblastic tumor seriously endangers child productive needs and the health of women in childbearing age. Nanodrug-based therapy mediated by transporters provides novel strategy for the treatment of trophoblastic tumors. Focus on the overexpressed human equilibrative nucleoside transporter 1 (ENT1) on the membrane of choriocarcinoma cells (JEG-3), the cytarabine (Cy, a substrate of ENT1) grafted liposome (Cy-Lipo) was introduced for targeted delivery of methotrexate (Cy-Lipo@MTX) for choriocarcinoma therapy in this study. The ENT1 has high affinity for Cy-Lipo and can mediate the endocytosis of the designed nanovehicles into JEG-3 cells. The ENT1 protein maintains its transporting function through circulation and regeneration during endocytosis. Therefore, Cy-Lipo-based formulations achieved high tumor accumulation and retention in pharmacokinetic and distribution studies. More importantly, the designed Cy-lipid conjugation exhibited a synergistic therapeutic effect on choriocarcinoma. Finally, Cy-Lipo@MTX exerts an extremely powerful anti-choriocarcinoma effect with fewer side effects. This study suggests that the overexpressed ENT1 on choriocarcinoma cells holds a great potential to be a high-efficiency target for the rational design of active targeting nanotherapeutics.

scholarly journals Concomitant polymorphs of aryl-ether amine via catemer and dimer carboxylic acid supramolecular interactions and their effect on optical properties

2021 ◽  
Author(s):  
Mehboobali Pannipara ◽  
Abdullah G Al-Sehemi
Keyword(s):  
Optical Properties ◽  
Carboxylic Acid ◽  
Crystal Lattice ◽  
Functional Groups ◽  
Molecular Orbital ◽  
Acid Group ◽  
Supramolecular Interactions ◽  
Aryl Ether ◽  
Stability Calculation ◽  
The Stability

Abstract Carboxylic acid supramolecular synthon exhibited dimer or catemer motifs in the crystal lattice depend on the substituent and other functional groups present in the structure. In general, presence of other competing functional groups produced catemer motifs whereas unsubstituted acids showed dimer. In this manuscript, we have synthesized a new aryl ether amine-based Schiff base with carboxylic acid functionality ( 1 ) and demonstrated polymorphic structure via catemer ( 1a ) and dimer ( 1b ) motifs in the solid state. In both the structure, carboxylic acid group adopted different orientation in the crystal lattice. The different H-bonding lead to modulation of optical properties that was further supported highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) calculation. Further the stability calculation indicates that catemer structure was more stable by 8.54 kcal/mole relative to dimer motifs. In contrast, naphthyl group attached carboxylic acid structure did not show neither dimer nor catemer motifs in the crystal lattice as compared to diethylaminophenyl group, which confirm the presence of other substituent or competing functional groups strongly influence on the motifs of supramolecular interactions.

scholarly journals Comprehensive Evaluation of Transition Metal Doped Ni3N to Construct High-Efficiency Hydrogen Evolution Catalyst

2021 ◽  
Author(s):  
Meng Wang ◽  
Zepeng Lv ◽  
Xuewei Lv ◽  
Qian Li ◽  
Jie Dang
Keyword(s):  
Transition Metal ◽  
Hydrogen Evolution ◽  
Density Functional ◽  
Rational Design ◽  
Dft Calculation ◽  
High Efficiency ◽  
Comprehensive Evaluation ◽  
Low Cost ◽  
Alkaline Electrolyte ◽  
Metal Doped

Abstract Density functional theory (DFT) calculation indicators (ΔG, densities of state, D-band and bader charge) are commonly used to predict and analyze the hydrogen evolution reaction (HER) activity of catalysts, and most studies discuss only one or few of these indicators’ impact on catalysis, but still no report has comprehensively evaluated the influence of all these indicators on catalytic performance. Herein, foreseen by comprehensive consideration first, we report transition metal doped Ni3N nanosheets combined on Ni foam for utra-efficient alkaline hydrogen evolution. For dual transition metals doped Ni3N, Co,V-Ni3N exhibits remarkable HER performance with a significantly low overpotential of only 10 mV in alkaline electrolyte and 41 mV in alkaline seawater electrolyte at 10 mA cm− 2; while for single transition metal doped Ni3N, V-Ni3N exhibits the best performance with an overpotential of 15 mV and a Tafel slope of 37 mV dec− 1. Our work highlights the importance of comprehensive evaluation of DFT calculation indexes, and opens up a new method for the rational design of efficient and low-cost catalysts.

scholarly journals De Novo Protein Design of Photochemical Reaction Centers

2021 ◽  
Author(s):  
Nathan Ennist ◽  
Zhenyu Zhao ◽  
Steven Stayrook ◽  
Bohdana Discher ◽  
P Leslie 'Les' Dutton ◽  
...  
Keyword(s):  
Reaction Center ◽  
Charge Separation ◽  
Rational Design ◽  
De Novo ◽  
Metal Cluster ◽  
Protein Structures ◽  
Essential Elements ◽  
Reaction Centers ◽  
Transient Absorption Spectroscopy

Abstract Natural photosynthetic protein complexes capture sunlight to power the energetic catalysis that supports life on Earth. Yet these natural protein structures carry an evolutionary legacy of complexity and fragility that encumbers protein reengineering efforts and obfuscates the underlying design rules for light-driven charge separation. De novo development of a simplified photosynthetic reaction center protein can clarify practical engineering principles needed to build new enzymes for efficient solar-to-fuel energy conversion. Here we report the rational design, X-ray crystal structure, and electron transfer activity of a multi-cofactor protein that incorporates essential elements of photosynthetic reaction centers. This highly stable, modular artificial protein framework can be reconstituted in vitro with interchangeable redox centers for nanometer-scale photochemical charge separation. Transient absorption spectroscopy demonstrates Photosystem II-like tyrosine and metal cluster oxidation, and we measure charge separation lifetimes exceeding 100 ms, ideal for light-activated catalysis. This de novo-designed reaction center builds upon engineering guidelines established for charge separation in earlier synthetic photochemical triads and modified natural proteins, and it shows how synthetic biology may lead to a new generation of genetically encoded, light-powered catalysts for solar fuel production.

scholarly journals METHODS FOR INCREASING EFFICIENCY OF HYDRAULIC RIGGING IN THE OIL PRODUCTION PROCESSES

2020 ◽  
pp. 32-38
Author(s):  
М. А. Куразов ◽  
З. Х. Газабиева ◽  
Р. Х. Моллаев ◽  
А. Ш. Халадов
Keyword(s):  
High Efficiency ◽  
Essential Elements ◽  
Oil Field ◽  
Hydraulic Pressure ◽  
Field Equipment ◽  
Field Development ◽  
Bottom Hole ◽  
Oil Flow ◽  
Complex Technology ◽  
Pumping Equipment

Гидравлический разрыв пласта (ГРП) представляет собой комплексную технологию обработок скважин. При этом его следует рассматривать не только как средство воздействия на призабойную зону пласта (ПЗП), но и как один из существенных элементов системы разработки месторождения в целом. Технологические схемы ГРП, в том числе с последующим химическим воздействием, различаются в зависимости от коллекторских свойств обрабатываемых объектов. Их эффективность определяется условиями, связанными с фильтрационными характеристиками пластов, то есть коэффициентами проницаемости близлежащих и удаленных зон объекта. При этом подход к проектированию обработок ГРП будет различным в низко- и высокопроницаемых пластах, и в этой связи грамотный выбор скважин имеет существенное значение. Для исключения смыкания трещин после ГРП и снятия давления в призабойной зоне пласта (ПЗП) в скважины закачиваются различные расклинивающие агенты. Расклинивающие агенты (проппанты) должны противостоять напряжениям горной породы, удерживая трещину раскрытой после снятия гидравлического давления жидкости разрыва и обеспечивая, таким образом, высокую фильтрационную способность призабойной зоны пласта и дебиты нефти скважин. Обработки скважин проводятся с использованием стандартного нефтепромыслового оборудования и насосной техники. Промысловый опыт ГРП в условиях Верхне-Салымского месторождения (Западная Сибирь) показал его достаточно высокую эффективность. Hydraulic fracturing is a complex technology of well treatment. At the same time it should be considered not only as a means of impact on the bottom-hole zone of the formation, but also as one of the essential elements of the field development system as a whole. Technological schemes of MPG, including with subsequent chemical impact, differ depending on collector properties of processed objects. Their effectiveness is determined by conditions related to filtration characteristics of formations, i. e. permeability coefficients of nearby and remote zones of the object. At the same time, the approach to the design of GRP treatments will be different in low and highly permeable formations and in this regard, competent selection of wells is essential. Various proppantsare pumped into wells to prevent closing of cracks after MPG and to relieve pressure in bottom-hole zone of formation. Proppants (proppants) must withstand rock stresses by holding the fracture open after the hydraulic pressure of the fracturing fluid has been removed, and thus ensuring high filtration capacity of the bottom-hole formation zone and well oil flow rate. Well treatments are carried out using standard oil field equipment and pumping equipment. The field experience of GRP in the conditions of Verkhne-Salymsky field (Western Siberia) showed its rather high efficiency.

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