bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scaffold‐Directed Face Selectivity Machine‐Learned from Vectors of Non‐covalent Interactions
Authors: Moskal Martyna , Beker Wiktor , Szymkuć Sara , Grzybowski Bartosz A. 
Published: April 2021

AbstractThis work describes a method to vectorize and Machine‐Learn, ML, non‐covalent interactions responsible for scaffold‐directed reactions important in synthetic chemistry. Models trained on this representation predict correct face of approach in ca. 90 % of Michael additions or Diels–Alder cycloadditions. These accuracies are significantly higher than those based on traditional ML descriptors, energetic calculations, or intuition of experienced synthetic chemists. Our results also emphasize the importance of ML models being provided with relevant mechanistic knowledge; without such knowledge, these models cannot easily “transfer‐learn” and extrapolate to previously unseen reaction mechanisms.
Efficient Intramolecular Charge‐Transfer Fluorophores Based on Substituted Triphenylphosphine Donors
Authors: Liu Zhang , Deng Chao , Su Liwu , Wang Dan , Jiang Yongshi , Tsuboi Taiju , Zhang Qisheng 
Published: April 2021

AbstractTriphenylphosphine (TPP)‐based luminescent compounds are rarely investigated because of the low photoluminescence quantum yield (PLQY). Here, we demonstrate that introducing steric hindrance groups to the TPP moiety and separating the orbitals involved in the transition can drastically suppress the non‐radiative decay induced by structural distortion of TPP in the excited state. High PLQY up to 0.89 as well as thermally activated delayed fluorescence are observed from the intramolecular charge‐transfer (ICT) molecules with substituted TPP donors (sTPPs) in doped films. The red organic light‐emitting diodes employing these emitters achieve comparable external quantum efficiencies to the control device containing a classical phosphorescent dye, revealing the great potential of the ICT emitters based on electrochemically stable sTPPs.
Supercharging Prions via Amyloid‐Selective Lysine Acetylation
Authors: Baumer Katelyn M. , Cook Christopher D. , Zahler Collin T. , Beard Alexandra A. , Chen Zhijuan , Koone Jordan C. , Dashnaw Chad M. , Villacob Raul A. , Solouki Touradj , Wood John L. , Borchelt David R. , Shaw Bryan F. 
Published: April 2021

AbstractRepulsive electrostatic forces between prion‐like proteins are a barrier against aggregation. In neuropharmacology, however, a prion's net charge (Z) is not a targeted parameter. Compounds that selectively boost prion Z remain unreported. Here, we synthesized compounds that amplified the negative charge of misfolded superoxide dismutase‐1 (SOD1) by acetylating lysine‐NH3+ in amyloid‐SOD1, without acetylating native‐SOD1. Compounds resembled a “ball and chain” mace: a rigid amyloid‐binding “handle” (benzothiazole, stilbene, or styrylpyridine); an aryl ester “ball”; and a triethylene glycol chain connecting ball to handle. At stoichiometric excess, compounds acetylated up to 9 of 11 lysine per misfolded subunit (ΔZfibril=−8100 per 103 subunits). Acetylated amyloid‐SOD1 seeded aggregation more slowly than unacetylated amyloid‐SOD1 in vitro and organotypic spinal cord (these effects were partially due to compound binding). Compounds exhibited reactivity with other amyloid and non‐amyloid proteins (e.g., fibrillar α‐synuclein was peracetylated; serum albumin was partially acetylated; carbonic anhydrase was largely unacetylated).
Synthesis, Electronic Structure, and Reactivity of a Planar Four‐Coordinate, Cobalt–Imido Complex
Authors: Park Yoonsu , Semproni Scott P. , Zhong Hongyu , Chirik Paul J. 
Published: April 2021

AbstractA four‐coordinate cobalt–imido complex, (tBumPNP)Co=NMes (tBumPNP=modified PNP pincer ligand) has been synthesized from addition of 2,4,6‐trimethylphenylazide (Mes–N3) to the corresponding dinitrogen complex. The solid‐state structure determined by X‐ray diffraction established a rare, idealized planar geometry with a Co=N bond distance of 1.716(2) Å. Magnetic measurements revealed an S=1 ground state with CAS‐SCF calculations supporting radical character on the imide nitrogen. Thermolysis of the cobalt–imido compound induced selective insertion of the imido group into a Co−P bond and yielded a three‐coordinate cobalt complex with a distorted T‐shaped geometry. Transition state analysis conducted with DFT calculations established the thermodynamic stability of the P–N coupled product and provided insight into the exclusive selectivity.
Anion⋅⋅⋅Anion Coinage Bonds: The Case of Tetrachloridoaurate
Authors: Daolio Andrea , Pizzi Andrea , Terraneo Giancarlo , Ursini Maurizio , Frontera Antonio , Resnati Giuseppe 
Published: April 2021

AbstractInteractions in crystalline tetrachloridoaurates of acetylcholine and dimethylpropiothetine are characterized by Au⋅⋅⋅Cl and Au⋅⋅⋅O short contacts. The former interactions assemble the AuCl4− units into supramolecular anionic polymers, while the latter interactions append the acetylcholine and propiothetine units to the polymer. The distorted octahedral geometry of the bonding pattern around the gold center is rationalized on the basis of the anisotropic distribution of the electron density, which enables gold to behave as an electrophile (π‐hole coinage‐bond donor). Computational studies prove that gold atoms in negatively charged species can function as acceptors of electron density. The attractive nature of the Au⋅⋅⋅Cl/O interactions described here complement the known aurophilic bonds involved in gold‐centered interactions.
Neither too Classic nor too Exotic: One‐Electron Na⋅B Bond in NaBH3− Cluster
Authors: Pino‐Rios Ricardo , Inostroza Diego , Tiznado William 
Published: April 2021

AbstractIt is here reported that the NaBH3− cluster exhibits a Na⋅B one‐electron bond, a well‐established type of electron‐deficient bonding in the literature. The topological analysis of the electron localization function, at the correlated level, reveals that Na−, when approaching the bonding distance, fairly distributes its valence electron pair between two lobes. One of these electrons is used to bond with BH3, which participates through its boron empty p‐orbital. Furthermore, the bonding situation of LiBH3−, KBH3−, MgBH3, and CaBH3 global minima structures are similar to that of NaBH3−, extending the family of these new one‐electron bond systems with biradicaloid character.
Synergistic Effect of Dielectric Property and Energy Transfer on Charge Separation in Non‐Fullerene‐Based Solar Cells
Authors: Li Pandeng , Fang Jin , Wang Yusheng , Manzhos Sergei , Cai Lei , Song Zheheng , Li Yajuan , Song Tao , Wang Xuechun , Guo Xia , Zhang Maojie , Ma Dongling , Sun Baoquan 
Published: April 2021

AbstractIn non‐fullerene‐based photovoltaic devices, it is unclear how excitons efficiently dissociate into charge carriers under small driving force. Here, we developed a modified method to estimate dielectric constants of PM6 donor and non‐fullerene acceptors. Surprisingly, most non‐fullerene acceptors and blend films showed higher dielectric constants. Moreover, they exhibited larger dielectric constants differences at the optical frequency. These results are likely bound to reduced exciton binding energy and bimolecular recombination. Besides, the overlap between the emission spectrum of donor and absorption spectra of non‐fullerene acceptors allowed the energy transfer from donor to acceptors. Hence, based on the synergistic effect of dielectric property and energy transfer resulting in efficient charge separation, our finding paves an alternative path to elucidate the physical working mechanism in non‐fullerene‐based photovoltaic devices.
Fabrication of active corrosion protection waterborne polyurethane coatings using cerium modified palygorskite nanocontainers
Authors: Ni Lingli , Li Shanshan , Liu Yongtao , Jiang Xiaowu , Cai Peng , Feng Liangdong , Zhang Shizhong , Gao Xiaoyan 
Published: April 2021

AbstractThe development of eco‐efficient and environmental friendly active anti‐corrosion coatings for metallic substrates represents a fundamental milestone in many engineering applications. Herein, a new type of active corrosion protection coating was successfully synthesized simply based on waterborne polyurethane (WPU) and nanocontainer of Ce3+ modified palygorskite (Ce‐PAL). Particularly, the nanocontainer of Ce‐PAL was achieved via a facile and green process by cation exchange in water. Inductively coupled plasma atomic emission spectrometry (ICP) revealed that Ce3+ had successfully incorporated into PAL nanofibers with a loading amount of 10.334 g/kg. The salt immersion test, electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy (EIS) demonstrated that the incorporation of Ce‐PAL only with 2 wt% into WPU led to a significant improvement of their corrosion protection properties. Finally, according to the results of scanning electron microscopy with energy dispersive X‐ray spectroscopy, the active anti‐corrosion mechanism of Ce‐PAL/WPU coating was proposed.
Collagen quantification in the ventricular walls of the heart of the common marmoset (Callithrix jacchus)
Authors: Senos Rafael , Gomes Benedicto Hildebrando , Macedo del Rio do Valle Cristiane , del Rio do Valle Rodrigo , L Nayudu Penelope , Roberto‐Rodrigues Mauro , Bombonato Pedro Primo 
Published: April 2021

AbstractThe excellent adaptability of Callithrix jacchus to life in captivity presents advantages in comparison to other nonhuman primates that are used in experimental models for biomedical research, which explains the increasing scientific interest in investigating the anatomical characteristics of this species. Owing to the relative scarcity of publications on the descriptive morphology of the heart of C. jacchus, the aim of this study was to quantify the presence of collagen in the left and right ventricular myocardium using modified picrosirius red and acid fuchsine colorimetric assays. The myocardium of the right ventricle presented a higher percentage of collagen than that of the left ventricle. No sex‐related differences were observed between the groups. Interestingly, the absolute values of collagen were different depending on the method used for quantification (modified picrosirius red vs. acid fuchsine). The level of collagen quantification observed in the ventricular myocardium of C. jacchus was similar to that seen in other nonhuman primates traditionally used in experimental models of cardiac diseases.
Hybridization‐based design of novel anticholinesterase indanone–carbamates for Alzheimer's disease: Synthesis, biological evaluation, and docking studies
Authors: Shahrivar‐Gargari Mohammad , Hamzeh‐Mivehroud Maryam , Hemmati Salar , Mojarrad Javid S. , Tüylü Küçükkılınç Tuba , Ayazgök Beyza , Dastmalchi Siavoush 
Published: April 2021

AbstractInspired by the structures of donepezil and rivastigmine, a novel series of indanone–carbamate hybrids was synthesized using the pharmacophore hybridization‐based design strategy, and their biological activities toward acetylcholinesterase (AChE) and butyrylcholinesterase were evaluated. Among the synthesized compounds, 4d and 4b showed the highest AChE inhibitory activities with IC50 values in the micromolar range (compound 4d: IC50 = 3.04 μM; compound 4b: IC50 = 4.64 μM). Moreover, the results of the Aβ1–40 aggregation assay revealed that compound 4b is a potent Aβ1–40 aggregation inhibitor. The kinetics of AChE enzymatic activity in the presence of 4b was investigated, and the results were indicative of a reversible partial noncompetitive type of inhibition. A molecular docking study was conducted to determine the possible allosteric binding mode of 4b with the enzyme. The allosteric nature of AChE inhibition by these compounds provides the opportunity for the design of subtype‐selective enzyme inhibitors. The presented indanone–carbamate scaffold can be structurally modified and optimized through medicinal chemistry‐based approaches for designing novel multitargeted anti‐Alzheimer agents.
Cytotoxic and antimicrobial potential of benzimidazole derivatives
Authors: Küçükbay Hasan , Uçkun Mustafa , Apohan Elif , Yeşilada Özfer 
Published: April 2021

AbstractNew benzimidazole derivatives were synthesized and their structures were characterized by spectroscopic and microanalysis techniques. The cytotoxic properties of ten benzimidazole derivatives, five of which were synthesized in our previous studies, were determined against the lung cancer cell line, A549, and the healthy lung epithelial cell line, BEAS‐2B. Among the ten compounds tested, based on the 72‐h incubation results, compound 12 was the most cytotoxic against the A549 cell line, whereas against the BEAS‐2B cell line, it was as cytotoxic as cisplatin. The IC50 values of compound 12 were 3.98 and 2.94 µg/ml for A549 and BEAS‐2B cells, respectively. The cisplatin values were 6.75 and 2.75 µg/ml for A549 and BEAS‐2B cells, respectively. Compounds 10, 8, 7, and 13 showed toxic effects against A549 cells, but were less toxic against BEAS‐2B cells than cisplatin. The antimicrobial activity of these compounds against pathogenic bacteria and yeasts was also evaluated based on their minimum inhibitory concentration (MIC) values. The compounds, except 12 and 13, generally showed higher antimicrobial activity against yeasts, compared with bacteria. Compound 12 showed better activity against Pseudomonas aeruginosa and Staphylococcus aureus than against Escherichia coli. Compounds 7, 8, and 11 were the most effective ones against the microorganisms, and yeasts were highly sensitive to these compounds with MIC values of 25–100 µg/ml.
Understanding the process of data reuse: An extensive review
Authors: Wang Xiaoguang , Duan Qingyu , Liang Mengli 
Published: April 2021

AbstractData reuse has recently become significant in academia and is providing new impetus for academic research. This prompts two questions: What precisely is the data reuse process? What is the connection between each participating element? To address these issues, 42 studies were reviewed to identify the stages and primary data reuse elements. A meta‐synthesis was used to locate and analyze the studies, and inductive coding was used to organize the analytical process. We identified three stages of data reuse—initiation, exploration and collection, and repurposing—and explored how they interact and form iterative characteristics. The results illuminated the data reuse at each stage, including issues of data trust, data sources, scaffolds, and barriers. The results indicated that multisource data and human scaffolds promote reuse behavior effectively. Further, two data and information search patterns were extracted: reticular centripetal patterns and decentralized centripetal patterns. Three paths with elements cooperating through flexible functions and motivated by different action items were identified: data centers, human scaffolds, and publications. This study supports improvements for data infrastructure construction, data reuse, and data reuse research by providing a new perspective on the effect of information behavior and clarifying the stages and contextual relationships between various elements.
Modification of the association between diabetes and birth defects by obesity, National Birth Defects Prevention Study, 1997–2011
Authors: Tinker Sarah C. , Gilboa Suzanne M. , Moore Cynthia A. , Waller D. Kim , Simeone Regina M. , Kim Shin Y. , Jamieson Denise J. , Botto Lorenzo D. , Fisher Sarah C. , Reefhuis Jennita ,   the National Birth Defects Prevention Study
Published: April 2021

AbstractBackgroundMaternal pregestational diabetes and obesity are risk factors for birth defects. Diabetes and obesity often occur together; it is unclear whether their co‐occurrence compounds birth defect risk.MethodsWe analyzed 1997–2011 data on 29,671 cases and 10,963 controls from the National Birth Defects Prevention Study, a multisite case‐control study. Mothers self‐reported height, pregestational weight, and diabetes (pregestational and gestational; analyzed separately). We created four exposure groups: no obesity or diabetes (referent), obesity only, diabetes only, and both obesity and diabetes. We estimated odds ratios (ORs) using logistic regression and the relative excess risk due to interaction (RERI).ResultsAmong mothers with pregestational obesity without diabetes, modest associations (OR range: 1.1–1.5) were observed for neural tube defects, small intestinal atresia, anorectal atresia, renal agenesis/hypoplasia, omphalocele, and several congenital heart defects. Pregestational diabetes, regardless of obesity, was strongly associated with most birth defects (OR range: 2.0–75.9). Gestational diabetes and obesity had a stronger association than for obesity alone and the RERI (in parentheses) suggested additive interaction for hydrocephaly (1.2; 95% confidence interval [CI]: −0.1, 2.5), tetralogy of Fallot (0.9; 95% CI: −0.01, 1.8), atrioventricular septal defect (1.1; 95% CI: −0.1, 2.3), hypoplastic left heart syndrome (1.1; 95% CI: −0.2, 2.4), and atrial septal defect secundum or not otherwise specified (1.0; 95% CI: 0.3, 1.6; only statistically significant RERI).ConclusionsOur results do not support a synergistic relationship between obesity and diabetes for most birth defects examined. However, there are opportunities for prevention by reducing obesity and improving glycemic control among women with pregestational diabetes before conception.
Cryo‐kinetics Reveal Dynamic Effects on the Chemistry of Human Dihydrofolate Reductase
Authors: Adesina Aduragbemi S. , Luk Louis Y. P. , Allemann Rudolf K. 
Published: April 2021

AbstractEffects of isotopic substitution on the rate constants of human dihydrofolate reductase (HsDHFR), an important target for anti‐cancer drugs, have not previously been characterized due to its complex fast kinetics. Here, we report the results of cryo‐measurements of the kinetics of the HsDHFR catalyzed reaction and the effects of protein motion on catalysis. Isotopic enzyme labeling revealed an enzyme KIE (kHLE/kHHE) close to unity above 0 °C; however, the enzyme KIE was increased to 1.72±0.15 at −20 °C, indicating that the coupling of protein motions to the chemical step is minimized under optimal conditions but enhanced at non‐physiological temperatures. The presented cryogenic approach provides an opportunity to probe the kinetics of mammalian DHFRs, thereby laying the foundation for characterizing their transition state structure.
Modulating the Acidic and Basic Site Concentration of Metal‐Organic Framework Derivatives to Promote the Carbon Dioxide Epoxidation Reaction
Authors: Ji Jinhua , Liu Hao , Chen Zewei , Fu Yajun , Yang Weijun , Yin Shuang‐Feng 
Published: April 2021

AbstractMetal‐organic framework (MOF) is an ideal precursor/template for porous carbon, and its active components are uniformly doped, which can be used in energy storage and catalytic conversion fields. Metal‐organic framework PCN‐224 with carboxylporphyrin as the ligand was synthesized, and then Zn2+ and Co2+ ions were coordinated in the center of the porphyrin ring by post‐modification. Here, PCN‐224−ZnCo with different ratios of bimetallic Zn2+/Co2+ ions were used as the precursor, and the metal‐nitrogen‐carbon(M−N−C) material of PCN‐224−ZnCo‐950 was obtained by pyrolyzing the precursor at 950 °C in Ar. Because Zn is easy to volatilize at 950 °C, the formed M−N−C materials can reflect different Co contents and different basic site concentrations. The formed material still maintains the original basic framework. With the increase of Zn2+/Co2+ ratio in precursor, the concentration of N‐containing alkaline sites in pyrolysis products gradually increase. Compared with the precursor, PCN‐224−ZnCo1‐950 with Zn2+/Co2+=1 : 1 has greatly improved basicity and suitable acidic/ alkaline site concentration. It can be efficiently used to carbon dioxide absorption and catalyze the cycloaddition of CO2 with epoxide. More importantly, the current method of adjusting the acidic/basic sites in M−N−C materials through volatilization of volatile metals can provide an effective strategy for adjusting the catalysis of MOF derivatives with porphyrin structure.
DNA Functionality with Photoswitchable Hydrazone Cytidine**
Authors: Mao Song , Chang Zhihua , Ying Zheng Ya , Shekhtman Alexander , Sheng Jia 
Published: April 2021

AbstractA new family of hydrazone modified cytidine phosphoramidite building block was synthesized and incorporated into oligodeoxynucleotides to construct photoswitchable DNA strands. The E‐Z isomerization triggered by the irradiation of blue light with a wavelength of 450 nm was investigated and confirmed by 1H NMR spectroscopy and HPLC in the contexts of both nucleoside and oligodeoxynucleotide. The light activated Z form isomer of this hydrazone‐cytidine with a six‐member intramolecular hydrogen bond was found to inhibit DNA synthesis in the primer extension model by using Bst DNA polymerase. In addition, the hydrazone modification caused the misincorporation of dATP together with dGTP into the growing DNA strand with similar selectivity, highlighting a potential G to A mutation. This work provides a novel functional DNA building block and an additional molecular tool that has potential chemical biology and biomedicinal applications to control DNA synthesis and DNA‐enzyme interactions using the cell friendly blue light irradiation.
Human Mass Balance and Metabolite Profiling of [14C]‐Pamiparib, a Poly (ADP‐Ribose) Polymerase Inhibitor, in Patients With Advanced Cancer
Authors: Mu Song , Palmer Daniel , Fitzgerald Richard , Andreu‐Vieyra Claudia , Zhang Heather , Tang Zhiyu , Su Dan , Sahasranaman Srikumar 
Published: April 2021

AbstractPamiparib, a selective poly (ADP‐ribose) polymerase 1/2 inhibitor, demonstrated tolerability and antitumor activity in patients with solid tumors at 60 mg orally twice daily. This phase 1 open‐label study (NCT03991494; BGB‐290‐106) investigated the absorption, metabolism, and excretion (AME) of 60 mg [14C]‐pamiparib in 4 patients with solid tumors. The mass balance in excreta, blood, and plasma radioactivity and plasma pamiparib concentration were determined along with metabolite profiles in plasma, urine, and feces. Unchanged pamiparib accounted for the most plasma radioactivity (67.2% ± 10.2%). Pamiparib was rapidly absorbed with a median time to maximum plasma concentration (Cmax) of 2.00 hours (range, 1.00‐3.05 hours). After reaching Cmax, pamiparib declined in a biphasic manner, with a geometric mean terminal half‐life (t1/2) of 28.7 hours. Mean cumulative [14C]‐pamiparib excretion was 84.7% ± 3.5%. Pamiparib was mainly cleared through metabolism, primarily via N‐oxidation and oxidation of the pyrrolidine ring. A dehydrogenated oxidative product (M3) was the most abundant metabolite in biosamples. A mean of 2.11% and 1.11% of [14C]‐pamiparib was excreted as unchanged pamiparib in feces and urine, respectively, indicating near‐complete absorption and low renal clearance of parent drug. Cytochrome P450 (CYP) phenotyping demonstrated CYP2C8 and CYP3A involvement in pamiparib metabolism. These findings provide an understanding of pamiparib AME mechanisms and potential drug‐drug interaction liability.