53,112 results match your criteria side chain


Synthesis of six-membered carbocyclic ring α,α-disubstituted amino acids and arginine-rich peptides to investigate the effect of ring size on the properties of the peptide.

Bioorg Med Chem 2021 Mar 19;38:116111. Epub 2021 Mar 19.

Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.

Cell-penetrating peptides (CPPs) have been attracting attention as tools for intracellular delivery of membrane-impermeant functional molecules. Among the variety of CPPs that have been developed, many are composed of both natural and unnatural amino acids. We previously synthesized α,α-disubstituted α-amino acids (dAAs) containing a five-membered carbocyclic ring in its side chain and revealed the utility of dAAs for the development of novel CPPs. Read More

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Crystal structure of BRP39, a signaling glycoprotein expressed during mammary gland apoptosis at 2.6 Å resolution.

J Struct Biol 2021 Apr 7:107737. Epub 2021 Apr 7.

Department of Chemistry, University of California Davis, Davis, California, 95616, United States; Department of Molecular and Cellular Biology, University of California Davis, Davis, California, 95616, United States.

Breast regression protein 39 (BRP39) is a 39 kDa protein that is a member of chitolectin class of glycosyl hydrolase family 18 (GH18). High expression levels of BRP39 have been detected in breast carcinoma. It helps in proliferation of cells during the progression of this disease and may act as a signaling factor. Read More

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Effect of Leu277 on Disproportionation and Hydrolysis Activity in NO2 Cyclodextrin Glucosyltransferase.

Appl Environ Microbiol 2021 Apr 9. Epub 2021 Apr 9.

State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China

The disproportionation activity of cyclodextrin glucosyltransferase (CGTase, EC 2.4.1. Read More

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A novel dextrin produced by the enzymatic reaction of 6-α-glucosyltransferase I: The effect of non-reducing ends of glucose with by α-1,6 bonds on the retrogradation inhibition of high molecular weight dextrin.

Biosci Biotechnol Biochem 2021 Apr 9. Epub 2021 Apr 9.

HAYASHIBARA CO., LTD., 675-1 Fujisaki, Naka-ku, Okayama 702-8006, Japan.

We prepared a high-molecular-weight modified dextrin (MWS-1000) from a partial hydrolysate of waxy corn starch with a weight average molecular weight of 1 × 106 (WS-1000) using Paenibacillus alginolyticus PP710 α-glucosyltransferase. The gel permeation chromatography showed that the weight average molecular weight of MWS-1000 was almost the same as that of WS-1000. The side chain length of WS-1000 and MWS-1000 after isomaltodextranase digestion were also shown to be similar to each other by high performance anion exchange chromatography with pulsed amperometric detection. Read More

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Flexibility and Cell Permeability of Cyclic Ras-Inhibitor Peptides Revealed by the Coupled Nosé-Hoover Equation.

J Chem Inf Model 2021 Apr 9. Epub 2021 Apr 9.

Graduate School of Simulation Studies, University of Hyogo, 7-1-28 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.

Quantifying the cell permeability of cyclic peptides is crucial for their rational drug design. However, the reasons remain unclear why a minor chemical modification, such as the difference between Ras inhibitors cyclorasin 9A5 and 9A54, can substantially change a peptide's permeability. To address this question, we performed enhanced sampling simulations of these two 11-mer peptides using the coupled Nosé-Hoover equation (cNH) we recently developed. Read More

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A tetravalent single-chain variable fragment antibody for the detection of staphylococcal enterotoxin A.

J Zhejiang Univ Sci B 2021 Apr;22(4):305-309

Key Laboratory of Environment Correlative Dietology, College of Food Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.

Staphylococcal enterotoxin A (SEA) synthesized by is a foodborne and heat-stable toxin, which is a great threat to human health (Pexaraet al., 2010). Highly sensitive antibodies are a key factor in the immunological detection of SEA, which is one of the most effective ways to detect SEA because of its accuracy, agility, and efficiency (Nouri et al. Read More

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[Trichophyton tonsurans-an emerging pathogen in wrestling in Germany].

Hautarzt 2021 Apr 9. Epub 2021 Apr 9.

Labor für medizinische Mikrobiologie - Partnerschaft Prof. Dr. med. Pietro Nenoff & Dr. med. Constanze Krüger, Mölbiser Hauptstr. 8, 04571, Rötha/OT Mölbis, Deutschland.

Trichophyton (T.) tonsurans is considered as the main causative agent of tinea gladiatorum (ringworm) in contact and martial arts worldwide and regularly leads to outbreaks. In the national wrestling squad in Leipzig, dermatophytoses occurred frequently and recurrently in children and adolescents for over a 2-year period. Read More

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[Effect of different orthodontic forces on the expression of T helper cell 17 cell-related cytokines in the pressure side of periodontal tissue in rats].

Hua Xi Kou Qiang Yi Xue Za Zhi 2021 Apr;39(2):143-152

Dept. of Orthodontics, Qingdao Stomatological Hospital Affiliated to Qingdao University, Qing-dao 266001, China.

Objectives: This study aimed to explore the changes in the expression of the characteristic transcription factor retinoid related orphan receptor γt (RORγt) and the cytokine interleukin-17 (IL-17) of T helper cell 17 (Th17) in the pressure side of the periodontal tissue of rats under different orthodontic forces. Their effects on the expression of osteoprotegerin (OPG) and the quantity of osteoclast (OC) were also explored. The role of Th17 cell in alveolar bone remodeling under different forces was preliminarily investigated. Read More

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Peptidoglycan Recognition Peptide 2 Aggravates Weight Loss in a Murine Model of Chemotherapy-Induced Gastrointestinal Toxicity.

Front Oncol 2021 23;11:635005. Epub 2021 Mar 23.

Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark.

Chemotherapy-induced gastrointestinal toxicity (CIGT) is a frequent, severe and dose-limiting side effect. Few treatments have proven effective for CIGT. CIGT is characterized by activation of the nuclear factor kappa B pathway which, leads to upregulation of proinflammatory cytokines. Read More

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Surface charged amino acid-based strategy for rational engineering of kinetic stability and specific activity of enzymes: Linking experiments with computational modeling.

Int J Biol Macromol 2021 Apr 5. Epub 2021 Apr 5.

College of Food Science and Engineering, Ocean University of China, Qingdao 266003, China. Electronic address:

A rational workflow for engineering kinetically stable enzymes with good specific activity by surface charged amino acids engineering was proposed based on systematically analyzing the results of mutating 44 negatively charged surface amino acids of a thermophilic β-mannanase (ManAK). Computational data, combined with experimental results indicated that percentage side-chain solvent accessibility (PSSA), changes in Gibbs free energy of unfolding (∆∆G) and root-mean-square fluctuations (RMSF) could be suitable for screening kinetically stable mutants. A combinational standard (∆∆G < -0. Read More

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Interaction of Alkali Ions with Flavins: Infrared and Optical Spectra of Metal-Riboflavin Complexes.

J Phys Chem A 2021 Apr 8. Epub 2021 Apr 8.

Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany.

Flavin compounds are of great interest in biochemistry because of their diverse functions in catalytic and photochemical processes. The intrinsic optical properties of flavins depend sensitively on their environment such as complexation with metal ions. Herein, we characterize the interaction of alkali metal ions (M) with riboflavin (RF, vitamin B). Read More

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Metal Binding Ability of Small Peptides Containing Cysteine Residues.

ChemistryOpen 2021 Apr;10(4):451-463

Department of Inorganic and Analytical Chemistry, University of Debrecen, Egyetem tér 1, 4032, Debrecen, Hungary.

The Cd(II)-, Pb(II)-, Ni(II)- and Zn(II)-complexes of small terminally protected peptides containing CXXX, XXXC, XCCX, CX C (n=1-3) sequences have been studied with potentiometric, UV/Vis and CD spectroscopic techniques. The cysteine thiolate group is the primary binding site for all studied metal ions, but the presence of a histidyl or aspartyl side chain in the molecule contributes to the stability of the complexes. For two-cysteine containing peptides the (S ,S ) coordinated species are formed in the physiological pH range and the stability increases in the Ni(II)Read More

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Synthesis and cytotoxicity evaluation of novel cyclic/non-cyclic -aryl enamino amides against human cancer cell lines.

Res Pharm Sci 2020 Dec 27;15(6):563-570. Epub 2020 Nov 27.

Department of Medicinal Chemistry, School of Pharmacy, Ardabil University of Medical Sciences, Ardabil, I.R. Iran.

Background And Purpose: Considering the undesirable consequences of prevalent cancer diseases, design and development of potent and selective anticancer chemotherapeutics is a major concern. Several studies have unraveled the potential of dihydropyrimidinone (DHPM) scaffold toward generating anticancer agents.

Experimental Approach: In the present work, a series of new dihydropyrimidinethiones (DHPMTs) along with a few acyclic enamino amides were synthesized and evaluated for their cytotoxic activity against human gastric (AGS), liver (Hep-G2), and breast (MCF-7) cancer cell lines. Read More

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December 2020

Contributing barriers to loss to follow up from antenatal care services in villages around Addis Ababa: a qualitative study.

BMC Womens Health 2021 Apr 7;21(1):140. Epub 2021 Apr 7.

JSI/ USAID Transform: Primary Health Care Activity, Addis Ababa, Ethiopia.

Background: Problems during pregnancy, childbirth and postpartum are the major contributors to maternal and perinatal morbidity and mortality. Focused antenatal care is an intervention set to provide basic services for pregnant women, to reduce morbidity and mortality related to pregnancy. In Ethiopia, there is a significant loss to follow up from antenatal care services between the first and fourth visits. Read More

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Enzymatic β-Oxidation of the Cholesterol Side Chain in Bifurcates Stereospecifically at Hydration of 3-Oxo-cholest-4,22-dien-24-oyl-CoA.

ACS Infect Dis 2021 Apr 7. Epub 2021 Apr 7.

Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States.

The unique ability of (Mtb) to utilize host lipids such as cholesterol for survival, persistence, and virulence has made the metabolic pathway of cholesterol an area of great interest for therapeutics development. Herein, we identify and characterize two genes from the Cho-region (genomic locus responsible for cholesterol catabolism) of the Mtb genome, (Rv3538) and (Rv3502c). Their protein products catalyze two sequential stereospecific hydration and dehydrogenation steps in the β-oxidation of the cholesterol side chain. Read More

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Protein Conjugation via SpyStapler-Mediated SpyTag/BDTag Coupling.

Curr Protoc 2021 Apr;1(4):e99

Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, P. R. China.

Genetically encoded peptide-protein coupling reactions, such as the SpyTag/SpyCatcher chemistry, are recent additions to the expanding toolbox of protein bioconjugation. The alternative three-component ligation system, e.g. Read More

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Posttranslational modifications in proteins: resources, tools and prediction methods.

Database (Oxford) 2021 Apr 7. Epub 2021 Apr 7.

Bioinformatics and Computational Omics Lab (BioCOOL), Department of Biophysics, Faculty of Biological Sciences Tarbiat Modares University, Jalal Ale Ahmad Highway, P.O. Box: 14115-111, Tehran, Iran.

Posttranslational modifications (PTMs) refer to amino acid side chain modification in some proteins after their biosynthesis. There are more than 400 different types of PTMs affecting many aspects of protein functions. Such modifications happen as crucial molecular regulatory mechanisms to regulate diverse cellular processes. Read More

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Reversible Transformation between Azo and Azonium Bond Other than Photoisomerization of Azo Bond in Main-Chain Polyazobenzenes.

J Phys Chem Lett 2021 Apr 7:3655-3661. Epub 2021 Apr 7.

Experimental Center for Advanced Materials, School of Materials Science and Engineering, Beijing Institute of Technology, No. 5, Zhongguancun South Street, Beijing 100081, China.

Although side-chain polyazobenzenes have been extensively studied, main-chain polyazobenzenes (abbreviated MCPABs) are rarely reported due to the challenges associated with difficulty in synthetic chemistry and photoisomerization of azo bonds in MCPABs. Thus, it is highly demanded to develop new mechanisms other than photoisomerization of azo bonds in MCPABs to extend their applications. In this work, we created a new series of N-linked MCPABs via fast NaBH-mediated reductive coupling polymerization on N-substituted bis(4-nitrophenyl)amines. Read More

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Protein identification from electron cryomicroscopy maps by automated model building and side-chain matching.

Acta Crystallogr D Struct Biol 2021 Apr 30;77(Pt 4):457-462. Epub 2021 Mar 30.

The Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.

Using single-particle electron cryo-microscopy (cryo-EM), it is possible to obtain multiple reconstructions showing the 3D structures of proteins imaged as a mixture. Here, it is shown that automatic map interpretation based on such reconstructions can be used to create atomic models of proteins as well as to match the proteins to the correct sequences and thereby to identify them. This procedure was tested using two proteins previously identified from a mixture at resolutions of 3. Read More

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REVIEW - Advancements in combination therapy of Hepatitis C virus.

Pak J Pharm Sci 2020 Sep;33(5):2171-2178

Department of Biochemistry, Government College University Faisalabad, Faisalabad, Pakistan.

Hepatitis C virus (HCV) is a primary cause of chronic liver disease along with various complications like liver cirrhosis and malignancy which leads to death. It has infected more than 185 million people worldwide. There is no congruence established for the treatment of various genotypes of HCV infection owing to diversity in prevalence globally. Read More

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September 2020

Dynamics of uniformly labelled solid proteins between 100 and 300 K: A 2D H-C MAS NMR approach.

Authors:
Ümit Akbey

J Magn Reson 2021 Mar 24;327:106974. Epub 2021 Mar 24.

Weizmann Institute of Science, Department of Chemical and Biological Physics, Perlman Chemical Sciences Building, P.O. Box 26, Rehovot 76100, Israel. Electronic address:

We describe a H based MAS nuclear magnetic resonance (NMR) method to obtain site-specific molecular dynamics of biomolecules. The method utilizes the use of deuterium nucleus as a spin label that is proven to be very useful in dynamics studies of solid biological and functional materials. The aim is to understand overall characteristics of protein backbone and side-chain motions for CD, CD and CD groups, in terms of timescale, type and activation energy of the underlying processes. Read More

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Chiral Alkyl Groups at Position 3(1') of Pyropheophorbide-a Specify Uptake and Retention by Tumor Cells and Are Essential for Effective Photodynamic Therapy.

J Med Chem 2021 Apr 6. Epub 2021 Apr 6.

PDT Center and Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, New York 14263, United States.

To investigate the importance of the chirality and precise structure at position 3(1') of pyropheophorbide-a for tumor cell specificity and photodynamic therapy (PDT), a series of photosensitizers (PSs) was synthesized: (a) with and without chirality at position 3(1'), (b) alkyl ether chain with a variable number of chiral centers, (c) hexyl ether versus thioether side chain, and (d) methyl ester versus carboxylic acid group at position 17. The cellular uptake and specificity were defined in human lung and head/neck cancer cells. PSs without a chiral center and with an alkyl chain or thioether functionalities showed limited uptake and PDT efficacy. Read More

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Modulating the Molecular Geometry and Solution Self-Assembly of Amphiphilic Polypeptoid Block Copolymers by Side Chain Branching Pattern.

J Am Chem Soc 2021 Apr 6. Epub 2021 Apr 6.

Department of Chemistry and Macromolecular Studies Group, Louisiana State University, Baton Rouge, Louisiana 70803, United States.

Solution self-assembly of coil-crystalline diblock copolypeptoids has attracted increasing attention due to its capability to form hierarchical nanostructures with tailorable morphologies and functionalities. While the N-substituent (or side chain) structures are known to affect the crystallization of polypeptoids, their roles in dictating the hierarchical solution self-assembly of diblock copolypeptoids are not fully understood. Herein, we designed and synthesized two types of diblock copolypeptoids, i. Read More

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A novel peptide design aids in the expression and its simplified process of manufacturing of Insulin Glargine in Pichia pastoris.

Appl Microbiol Biotechnol 2021 Apr 5. Epub 2021 Apr 5.

Biocon Biologics Limited (BBL), Science and Technology Innovation Center (SNTI), Biocon Park, Plot No. 2 & 3, Bommasandra Industrial Estate, IV Phase, Bommasandra Jigani Link Road, Bangalore, 560 099, India.

Manufacturing of insulin and its analogues relied upon in vitro enzymatic cleavages of its precursor forms (single chain precursor, SCP) at both ends of a connecting peptide (C-peptide) that links the respective B-chain and A-chains to corresponding final forms. We have demonstrated a simplified approach of cleaving P. pastoris expressed SCP, distinctly at one site for conversion to insulin glargine. Read More

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Ecdysteroid metabolism in mammals: the fate of ingested 20-hydroxyecdysone in mice and rats.

J Steroid Biochem Mol Biol 2021 Apr 2:105896. Epub 2021 Apr 2.

Biophytis, Sorbonne Université - BC9, 4 place Jussieu, 75005, Paris, France; Sorbonne Université, CNRS - Institut de Biologie Paris Seine (BIOSIPE), 75005, Paris, France. Electronic address:

Phytoecdysteroids are molecules derived from sterol metabolism and found in many plants. They display a wide array of pharmacological effects on mammals (e.g. Read More

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Lipid-Dependent Titration of Glutamic Acid at a Bilayer Membrane Interface.

ACS Omega 2021 Mar 17;6(12):8488-8494. Epub 2021 Mar 17.

Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, United States.

The ionization properties of protein side chains in lipid-bilayer membranes will differ from the canonical values of side chains exposed to an aqueous solution. While the propensities of positively charged side chains of His, Lys, and Arg to release a proton in lipid membranes have been rather well characterized, the propensity for a negatively charged Glu side chain to receive a proton and achieve the neutral state in a bilayer membrane has been less well characterized. Indeed, the ionization of the glutamic acid side chain has been predicted to depend on its depth of burial in a lipid membrane but has been difficult to verify experimentally. Read More

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Influence of Potential Gene Polymorphisms on Propofol Dosage Regimen in Patients Undergoing Abdominal Hysterectomy.

Balkan J Med Genet 2020 Nov 23;23(2):41-48. Epub 2021 Mar 23.

University Clinic for Gynecology and Obstetrics, University "Ss Cyril and Methodius" Medical Faculty, Skopje, Republic of North Macedonia.

Propofol (2,6-diisopropylphenol) is the most common intravenous anesthetic used in modern medicine. It is postulated that individual differences in genetic factors [polymorphism of single nucleotide polymorphisms (SNPs)] in the genes encoding metabolic enzymes, molecular targets and molecular binding sites of propofol can be responsible for susceptibility to propofol effects. The aim of our study was to investigate the influence of the cytochrome P450 2B6 isozyme (rs3745274), γ-aminobutyric acid type A (GABAA) receptor α1 subunit (rs2279020) and ATP-binding cassette subfamily B member 1 (rs1045642) gene polymorphisms on propofol therapeutic outcomes in the patients undergoing abdominal hysterectomy. Read More

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November 2020

Two-color, ultra-sensitive fluorescent strategy for Ochratoxin A detection based on hybridization chain reaction and DNA tweezers.

Food Chem 2021 Mar 23;356:129663. Epub 2021 Mar 23.

School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China. Electronic address:

A two-color fluorescent DNA tweezers was developed for ultrasensitive detection of Ochratoxin A (OTA) based on hairpin-locked aptamer and hybridization chain reaction (HCR) amplification strategy. OTA can bind with hairpin-locked aptamer and then trigger the HCR reaction to produce a long double-strand DNA. The side-chains of the long duplex can separately hybridize with the two locker sequences of DNA tweezer, causing the opening of DNA tweezer and the recovery of two-color fluorescent signals. Read More

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Solution NMR structure of titin N2A region Ig domain I83 and its interaction with metal ions.

J Mol Biol 2021 Mar 31:166977. Epub 2021 Mar 31.

School of Cardiovascular Medicine and Sciences and Randall Centre, King's College London, Guy's Campus, London, SE1 1UL, UK. Electronic address:

Titin, the largest single chain protein known so far, has long been known to play a critical role in passive muscle function but recent studies have highlighted titin's role in active muscle function. One of the key elements in this role is the Ca-dependent interaction between titin's N2A region and the thin filament. An important element in this interaction is I83, the terminal immunoglobulin domain in the N2A region. Read More

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The Effect of Alkyl Substitution of Novel Imines on Their Supramolecular Organization, towards Photovoltaic Applications.

Polymers (Basel) 2021 Mar 26;13(7). Epub 2021 Mar 26.

Centre of Polymer and Carbon Materials, Polish Academy of Sciences, 34 M. Curie-Skłodowska Str., 41-819 Zabrze, Poland.

Three novel conjugated polyazomethines have been obtained by polycondensation of diamines consisting of the diimine system, with either 2,5-bis(octyloxy)terephthalaldehyde or 9-(2-ethylhexyl)carbazole-3,6-dicarboxaldehyde. Partial replacement of bulky solubilizing substituents with the smaller side groups has allowed to investigate the effect of supramolecular organization. All obtained compounds have been subsequently identified using the NMR and FTIR spectroscopies and characterized by the thermogravimetric analysis, differential scanning calorimetry, cyclic voltammetry, UV-Vis spectroscopy, and X-ray diffraction. Read More

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