bluuebunny/crossref_metadata_2025_split huggingface dataset:
N‐Halogenation by Vanadium‐Dependent Haloperoxidases Enables 1,2,4‐Oxadiazole Synthesis
Authors: Sharma Manik , Patton Zoe E. , Shoemaker Carlie R. , Bacsa John , Biegasiewicz Kyle F. 
Published: August 2024

AbstractNitrogen‐containing compounds are valuable synthetic intermediates and targets in nearly every chemical industry. While methods for nitrogen‐carbon and nitrogen‐heteroatom bond formation have primarily relied on nucleophilic nitrogen atom reactivity, molecules containing nitrogen‐halogen bonds allow for electrophilic or radical reactivity modes at the nitrogen center. Despite the growing synthetic utility of nitrogen‐halogen bond‐containing compounds, selective catalytic strategies for their synthesis are largely underexplored. We recently discovered that the vanadium‐dependent haloperoxidase (VHPO) class of enzymes are a suitable biocatalyst platform for nitrogen‐halogen bond formation. Herein, we show that VHPOs perform selective halogenation of a range of substituted benzamidine hydrochlorides to produce the corresponding N’‐halobenzimidamides. This biocatalytic platform is applied to the synthesis of 1,2,4‐oxadiazoles from the corresponding N‐acylbenzamidines in high yield and with excellent chemoselectivity. Finally, the synthetic applicability of this biotechnology is demonstrated in an extension to nitrogen‐nitrogen bond formation and the chemoenzymatic synthesis of the Duchenne muscular dystrophy drug, ataluren.
Nanoporous Heterojunction Photocatalysts with Engineered Interfacial Sites for Efficient Photocatalytic Nitrogen Fixation
Authors: Yuan Ling , Tang Cheng , Du Peiyang , Li Jiaxin , Zhang Chaoqi , Xi Yamin , Bi Yin , Bao Tong , Du Aijun , Liu Chao , Yu Chengzhong 
Published: August 2024

AbstractPhotocatalytic N2 reduction reaction (PNRR) offers a promising strategy for sustainable production of ammonia (NH3). However, the reported photocatalysts suffer from low efficiency with great room to improve regarding the charge carrier utilization and active site engineering. Herein, a porous and chemically bonded heterojunction photocatalyst is developed for efficient PNRR to NH3 production via hybridization of two semiconducting metal—organic frameworks (MOFs), MIL‐125−NH2 (MIL=Material Institute Lavoisier) and Co‐HHTP (HHTP=2,3,6,7,10,11‐hexahydroxytripehenylene). Experimental and theoretical results demonstrate the formation of Ti−O−Co chemical bonds at the interface, which not only serve as atomic pathway for S‐scheme charge transfer, but also provide electron‐deficient Co centers for improving N2 chemisorption/activation capability and restricting competitive hydrogen evolution. Moreover, the nanoporous structure allows the transportation of reactants to the interfacial active sites at heterojunction, enabling the efficient utilization of charge carriers. Consequently, the rationally designed MOF‐based heterojunction exhibits remarkable PNRR performance with an NH3 production rate of 2.1 mmol g−1 h−1, an apparent quantum yield (AQY) value of 16.2 % at 365 nm and a solar‐to‐chemical conversion (SCC) efficiency of 0.28 %, superior to most reported PNRR photocatalysts. Our work provides new insights into the design principles of high‐performance photocatalysts.
Synthesis, Structural Elucidation, Density Functional Theory Calculations, In Vitro Antimicrobial, Anti‐Inflammatory and Anticancer Activities of Novel Zn (II)‐Group Fourteen Heterobimetallic Complexes Derived From Schiff Base Ligand
Authors: Mamta  , Chaudhary Ashu 
Published: August 2024

ABSTRACTIn the present work, new heterobimetallic complexes with the general formula [Zn(C16H32N8)M2(R)4Cl2], where M = Sn (IV) and Si (IV) and R = ‐CH3 and ‐C6H5, were synthesized by reacting the methanolic solution of the monometallic complex [Zn(C16H36N8)Cl2] with group 14 organometallic dichloride [(CH3)2SnCl2/(C6H5)2SnCl2/(CH3)2SiCl2/(C6H5)2SiCl2]. The structures of the synthesized complexes were determined using several spectrometric techniques, including FT‐IR, 1H NMR, 13C NMR, 119Sn NMR, 29Si NMR, ESI‐MS, PXRD, and molar conductivity measurements. Density functional theory (DFT) calculations were carried out to investigate the quantum chemical characteristics of the newly synthesized Zn (II) complexes. The antimicrobial potential of the monometallic and heterobimetallic complexes was evaluated against two Gram‐positive bacteria (Bacillus subtilis and Bacillus cereus), two Gram‐negative bacteria (Xanthomonas campestris and Pseudomonas aeruginosa), and two fungal strains (Aspergillus flavus and Fusarium oxysporum) by the agar well diffusion method, with heterobimetallic complex [Zn(C16H32N8)Sn2(C6H5)4Cl2] as the most potent complex against microbes. The complex [Zn(C16H32N8)Sn2(C6H5)4Cl2] exhibited significant potential in inhibiting inflammation, demonstrating an IC50 value of 9.75 μg/mL, which closely rivals that of the standard drug sodium diclofenac (IC50 = 4.59 μg/mL). Furthermore, all the synthesized compounds were assessed for their anticancer potential against three cancer cell lines (HCT‐116, MCF‐7, and HeLa) by the MTT assay. The results indicated that the complex [Zn(C16H32N8)Sn2(C6H5)4Cl2] exhibited the most pronounced cytotoxic effects, with values of 4.25 ± 0.15 μM, 4.90 ± 0.18 μM, and 5.20 ± 0.24 μM observed for HCT‐116, MCF‐7, and HeLa cancer cell lines, respectively.
Clinicopathological features of hepatoid adenocarcinoma and non‐hepatoid adenocarcinoma of the stomach: A systematic review and meta‐analysis
Authors: Ling Qi , Liu Han‐Lin , Huang Shi‐Ting , Sun Li‐Fei , Wu Wei‐Wei , Kudriashov Valentin , Liu Kai , Yang Kun , Hu Jian‐Kun , Zhang Wei‐Han 
Published: August 2024

AbstractBackgroundHepatoid adenocarcinoma of the stomach (HAS) is an extremely rare and unique malignant gastric tumor with a significantly worse prognosis than non‐hepatoid adenocarcinoma of the stomach (non‐HAS). The present study explored the clinicopathological features of HAS and non‐HAS patients to provide insights into HAS treatment strategies.MethodsFrom December 26, 2023, we performed a comprehensive search of the PubMed, Web of Science, Cochrane Library, and Embase.com databases for relevant studies. Two authors independently screened the studies, evaluated their quality, extracted data, and performed the analyses. This study was registered with PROSPERO on January 2, 2024.ResultsNine retrospective studies were included for analysis after screening 833 articles. A total of 350 and 924 patients were enrolled in the HAS and non‐HAS groups, respectively. While no significant differences were observed in age, sex, tumor size, T3 or T4 stage, and N2 or N3 stage between the two groups, the HAS group exhibited higher rates of lymph node metastasis (OR = 1.93, 95% CI: 1.19–3.13, p = 0.007), liver metastasis (OR = 3.45, 95% CI: 2.26–5.28, p < 0.001), and vascular invasion (OR = 2.76, 95% CI: 2.05–3.71, p < 0.001). Additionally, the HAS group had lower 3‐year survival rates (HR = 2.35, 95% CI: 1.70–3.25, p < 0.001) and 5‐year survival rates (HR = 3.63, 95% CI: 1.49–8.88, p = 0.005), but lower rates of lymphatic permeation (OR = 0.68, 95% CI: 0.47–0.99, p = 0.040).ConclusionBased on the current clinical evidence, patients with HAS present distinct clinicopathological features, greater invasiveness, and poorer prognosis than non‐HAS patients. Further research is warranted to develop optimal treatment strategies for HAS.
Exploring the influence of submission devices on customer referral creation and receiver reactions in customer referral programs
Authors: Wolf Lukas , Klopfer Lisa‐Marie , Steul‐Fischer Martina , Reinsperger Maximilian 
Published: August 2024

AbstractCustomer referral programs (CRPs) are considered an effective means of customer acquisition through which firms stimulate existing customers to refer services and products to potential new customers. Digitalization and technological developments have led to the common practice of using digital devices like smartphones or laptops to create and submit customer referrals. This is the first study to investigate the influence of submission devices in CRPs from both the sender's and receiver's perspective. Based on four experiments, we demonstrate that smartphone‐generated referrals are shorter and less positive than those composed on laptops/PCs. These differences in text length and valence negatively influence receiver responses, leading to lower purchase intentions due to the perceived usefulness of the referral mediating this relationship. Our findings underscore the important role of submission devices for online referral behavior and contribute to the growing body of research on device‐mediated consumer behavior, offering crucial insights to optimize the promotion and design of CRPs.
Exploration of Potential Anti‐Inflammatory Cum Anti‐Rheumatoid‐Arthritis Phyto‐Molecule Through Integrated Green Approach: Network Pharmacology, Molecular Docking, Molecular Dynamics, In‐Vitro and Ex‐Vivo Study
Authors: Kumar Amresh , Ashif Ikbal Abu Md , Ahmed Laskar Monjur , Sarkar Avik , Saha Abhishek , Bhardwaj Prashant , Das Suprio , Kumar Singh Santosh , Ghosh Parasar , Kargarzadeh Hanieh , Palit Partha , Dutta Choudhury Manabendra 
Published: August 2024

AbstractRheumatoid arthritis (RA) and associated inflammatory complications are the most prevalent illnesses and can turn into fatal conditions if left untreated. Allopathic medicine is not satisfactory for curing RA. Scientific literature reports reveal that several phyto‐compounds viz. flavonoids, saponins, and terpenoids, can heal joints and organs from auto‐inflammatory rheumatoid arthritis and pain. Gene ontology, gene network analysis, molecular clustering, and literature review were used to optimise RA‐specific highly expressed genes. In‐silico molecular docking was performed to short‐out potential phytomolecules (Neohesperidin dihydrochalcone (NHDC)) from 1000 datasets‐library against RA and validate using MD simulation running at 100 ns. In‐vitro anti‐inflammatory assays of NHDC inhibited egg‐albumin denaturation, IC50 of 47.739±0.51 μg/ml. The ex‐vivo MTT assay with NHDC rendered 67.209 % inhibition at 100 μM against fd‐FLS‐cells. NHDC downregulated pro‐inflammatory cytokine IL‐17 A production by 61.11 % and 50 % at 300 and 200 μM, respectively. Thus, this Studies recommend that NHDC may be highlighted as a novel multi‐target PADI4 and JAK3 inhibitor with better efficacy and minimal toxicity in RA warranted to In‐Vivo and clinical investigation. The current findings have uncovered remarkable genes and signalling pathways linked to RA, which could enhance our existing comprehension of the molecular mechanisms that drive its development and progression.
Cytotoxic and Antitumor Agents from Genus Rubia
Authors: Xu Geng , Liu Meiyu , Wang Zuobin , Chen(s) Yujuan 
Published: August 2024

AbstractGenus Rubia is widely distributed in almost all regions of the world, with 36 species and 2 varieties in China. Rubia species, such as Rubia cordifolia, have been used in traditional Chinese medicine for the treatment of diseases since ancient times. In recent years, the study of anticancer effects in traditional Chinese medicine has become a popular topic, and some studies have shown that several Rubia species extracts have cytotoxic and antitumor effects, and some of them have been shown to contain specific antitumor agents. Therefore, this review focuses on the cytotoxic and antitumor effects of the chemical constituents contained in Genus Rubia. Summarized 71 types of chemical substances in 5 categories with the effect of cytotoxicity and antitumor, as well as their structures, targets and mechanisms of action.
Redox‐Activated Substrates for Enhancing Activatable Cyclopropene Bioorthogonal Reactions
Authors: Kao Wei‐Siang , Huang Wei , Zhang Yunlei , Wen Kangqiao , Meyer Andrea , Escorihuela Jorge , Laughlin Scott T. 
Published: August 2024

AbstractBioorthogonal chemistry has become a mainstay in chemical biology and is making inroads in the clinic with recent advances in protein targeting and drug release. Since the field's beginning, a major focus has been on designing bioorthogonal reagents with good selectivity, reactivity, and stability in complex biological environments. More recently, chemists have imbued reagents with new functionalities like click‐and‐release or light/enzyme‐controllable reactivity. We have previously developed a controllable cyclopropene‐based bioorthogonal ligation, which has excellent stability in physiological conditions and can be triggered to react with tetrazines by exposure to enzymes, biologically significant small molecules, or light spanning the visual spectrum. Here, to improve reactivity and gain a better understanding of this system, we screened diene reaction partners for the cyclopropene. We found that a cyclopropene–quinone pair is 26 times faster than reactions with 1,2,4,5‐tetrazines. Additionally, we showed that the reaction of the cyclopropene–quinone pair can be activated by two orthogonal mechanisms: caging group removal on the cyclopropene and oxidation/reduction of the quinone. Finally, we demonstrated that this caged cyclopropene–quinone can be used as an imaging tool to label the membranes of fixed, cultured cells.
Phosphorylation of the HMGN1 Nucleosome Binding Domain Decreases Helicity and Interactions with the Acidic Patch
Authors: Iebed Dina , Gökler Tobias , van Ingen Hugo , Conibear Anne C. 
Published: August 2024

AbstractIntrinsically disordered proteins are abundant in the nucleus and are prime sites for posttranslational modifications that modulate transcriptional regulation. Lacking a defined three‐dimensional structure, intrinsically disordered proteins populate an ensemble of several conformational states, which are dynamic and often altered by posttranslational modifications, or by binding to interaction partners. Although there is growing appreciation for the role that intrinsically disordered regions have in regulating protein‐protein interactions, we still have a poor understanding of how to determine conformational population shifts, their causes under various conditions, and how to represent and model conformational ensembles. Here, we study the effects of serine phosphorylation in the nucleosome‐binding domain of an intrinsically disordered protein – HMGN1 – using NMR spectroscopy, circular dichroism and modelling of protein complexes. We show that phosphorylation induces local conformational changes in the peptide backbone and decreases the helical propensity of the nucleosome binding domain. Modelling studies using AlphaFold3 suggest that phosphorylation disrupts the interface between HMGN1 and the nucleosome acidic patch, but that the models over‐predict helicity in comparison to experimental data. These studies help us to build a picture of how posttranslational modifications might shift the conformational populations of disordered regions, alter access to histones, and regulate chromatin compaction.
Chemoenzymatic Synthesis of Plant‐Derived Kavalactone Natural Products by Dynamic Resolution Using a Biosynthetic O‐Methyltransferase Tailoring Enzyme
Authors: Rydzek Simon , Guth Florian , Friedrich Steffen , Noske Jakob , Höcker Birte , Hahn Frank 
Published: August 2024

AbstractBiosynthetic enzymes have enormous potential for the chemoenzymatic synthesis of natural products and other bioactive compounds. Methyltransferases are promising tools for the selective enzymatic modification of complex structures. This paper describes the production, purification and biochemical characterization of the O‐methyltransferase JerF, which catalyzes unique 4‐methoxy‐5,6‐dihydropyranone formation in jerangolid A biosynthesis. Isolation problems had hitherto prevented detailed studies on JerF and were solved by the fusion to maltose‐binding protein. The differentiation of JerF between styryl‐substituted dihydropyrandion enantiomers was investigated. In combination with a spontaneous racemization occurring with this type of substrates, a new enzymatic dynamic kinetic resolution was observed, which was used for the enantioselective chemoenzymatic synthesis of kavalactone natural products and new derivatives. In combination with an HMT‐based SAM regeneration system, (+)‐kavain, (+)‐11,12‐dimethoxykavain and (+)‐12‐fluorokavain were prepared in 3–4 steps on a 100 μmol scale with overall yields of 37–57 % and ees of 70–86 %. A mutational study based on an AlphaFold 2 model provided indications for active site residues with an influence on the performance of the enzyme that could be targeted for engineering in the future. This example illustrates how the exceptional enzymatic activities and specificities of biosynthetic enzymes can be exploited for the development of new synthesis approaches.
Tandem Hydrocyanation and Nitrile/Amide Cyclization of Propiolamides: A Rapid Access to 5‐Iminopyrrolones
Authors: Hu Jiawen , Wang Suliang , Wang Lingna , Long Jinguo , Fang Xianjie 
Published: August 2024

AbstractA Pd‐catalyzed synthesis of 5‐iminopyrrolones from propiolamides was developed, which featured wide substrate scope and good yields. This efficient conversion involved a tandem hydrocyanation, E to Z isomerization of alkenes, and nitrile/amide cyclization. Control experiments show the intermediacy of β‐cyanation products, and the Z‐isomers was efficiently converted to the target products by Pd/L2 catalysis only after the cyanation reagent was completely consumed.
Chemometric Classification of Motor Oils Using 1H NMR Spectroscopy With Simultaneous Phase and Baseline Optimization
Authors: Olejniczak A. , Łukaszewicz J. P. 
Published: August 2024

ABSTRACTHere, we demonstrate mid‐field 1H NMR spectroscopy combined with chemometrics to be powerful in the classification and authentication of motor oils (MOs). The 1H NMR data were processed with a new algorithm for simultaneous phase and baseline correction, which, for crowded spectra such as those of the refinery products, allowed for more accurate estimation of phase parameters than other literature approaches tested. A principal component analysis (PCA) model based on the unbinned CH3 fingerprint region (0.6–1.0 ppm) enabled the differentiation of hydrocracked and poly‐α‐olefin‐based MOs and was effective in resolving mixtures of these base stocks with conventional base oils. PCA analysis of the 1.0‐ to 1.14‐ppm region enabled the detection of poly (isobutylene) additive and was useful for differentiating between single‐grade and multigrade MOs. Non‐equidistantly binned 1H NMR data were used to detect the addition of esters and to establish discriminant models for classifying MOs by viscosity grade and by major categories of synthetic, semisynthetic, and mineral oils. The performances of four classifiers (linear discriminant analysis [LDA], quadratic discriminant analysis [QDA], naïve Bayes classifier [NBC], and support vector machine [SVM]) with and without PCA dimensionality reduction were compared. In both tasks, SVM showed the best efficiency, with average error rates of ~2.3% and 8.15% for predicting major MO categories and viscosity grades, respectively. The potential to merge spectra collected from different NMR instruments is discussed for models based on spectral binning. It is also shown that small errors in phase parameters are not detrimental to binning‐based PCA models.
Synthetic Investigation toward Acyl Group‐Free Escin Derivatives
Authors: Lv Xin , Liao Jin‐Xi , Li Zhen‐Qiang , Xiong Zhi‐Sheng , Yin Qi‐Shuang , Liu Hui , Tu Yuan‐Hong , Sun Jian‐Song 
Published: August 2024

Comprehensive SummaryWith protoescigenin as starting material and through orchestrated application of Yu and Schmidt glycosylation protocols, the synthesis of acyl group‐free escin derivatives was achieved for the first time. As the undesired non‐specific toxicity, originating from the existence of acyl groups on aglycone, prohibits the wide application of escins, the established strategies toward non‐acylated protoescigenin‐type saponins would dramatically ease the access to escin derivatives dispense of acyl groups, thereby speeding up the pace of pharmaceutical use of these valuable compounds.
Chromophoric Keratin‐Cysteine Particle Synthesis Using Factorial Design of Experiment
Authors: Damatov Yaniv , Nowogrodski Chen , Shoseyov Oded 
Published: August 2024

AbstractThe quest for novel chromophoric materials with tunable properties to match the natural spectrum of skin tones lacks comprehensive solutions, particularly in harnessing natural proteins for pigment synthesis. This research delved into the synthesis of sub‐micron Keratin‐Cysteine particles inspired by natural pigment production pathways. Adjustment of the initial conditions of the water‐based reaction between keratin, tyrosinase and cysteine, yielded Keratin‐Cysteine particles with colors tunable within the light to intermediate skin tone range. A systematic investigation of the reaction conditions through factorial design of experiment (DOE) identified the sequence of addition of tyrosinase and cysteine as the key determinant of color tone. Ultraviolet‐visible (UV‐Vis) spectroscopy, attenuated total reflectance Fourier transform infrared (ATR‐FTIR) spectroscopy and color analysis were performed to elucidate the reaction mechanism. This research presents a promising approach to chromophore synthesis for cosmetic and biomedical applications.
Experimental Elucidation of a Cubane Water Cluster in the Hydrophobic Cavity of UiO‐66
Authors: Sonobe Kazutaka , Tominaka Satoshi , Machida Akihiko 
Published: August 2024

AbstractNanoscale water plays a pivotal role in determining the properties and functionalities of materials, and the precise control of its quantity and atomic‐scale ordered structure is a focal point in nanotechnology and chemistry. Several studies have theoretically discussed the nano‐ordered ice within one‐ or two‐dimensional space and without confinement through hydrogen bonds. In particular, the water cluster has been predicted to play a significant role in biomolecules or functional nanomaterials; however, there has been little experimental evidence for their presence in hydrophobic cavities. In this study, the cubane water octamer – the most stable isomer among small water clusters – was detected within the hydrophobic cavities of UiO‐66 metal–organic frameworks, revealing the presence of the smallest ice in their hydrophobic cavity, in the absence of hydrogen bonding. This observation contrasts earlier examples of water clusters confined within nanocavities through hydrogen bonds and provides experimental evidence for water‐cluster capturing within hydrophobic cavities. Consequently, our renewed understanding of hydrophilicity and hydrophobicity warrants a design re‐evaluation of materials for chemical applications, including fuel cells, water harvesting, catalysts, and batteries.
Organic and Non‐Precious Metal Photosensitizers for Photocatalytic CO2 Reduction
Authors: Xue Yilin , Chao Duobin 
Published: August 2024

AbstractCarbon dioxide (CO2) is the primary greenhouse gas responsible for global warming, posing a significant challenge to the global environment. To reduce CO2 emission and support the sustainable development, efficient conversion of CO2 into chemical feedstocks has gained a lot of attention. One promising strategy inspired by natural photosynthesis is solar‐driven CO2 reduction, which uses appropriate photocatalytic systems to generate CO, HCOOH, CH4, CH3OH, etc. However, developing low‐cost, environmentally friendly, and non‐toxic materials for the catalytic conversion of CO2 remains a significant challenge. Light‐absorbing photosensitizers play an important role in photocatalytic systems. Recently, non‐precious metal photosensitizers such as organic compounds and earth‐abundant metal complexes have been intensively studied for developing low‐cost photocatalytic systems. This review focuses on recent reports on organic and non‐precious metal photosensitizers for photocatalytic CO2 reduction.