bluuebunny/crossref_metadata_2025_split huggingface dataset:
Zirconium‐Salan Catalyzed Enantioselective α‐Hydroxylation of β‐Keto Esters
Authors: Chen Jie , Gu Haiyang , Zhu Xueying , Nam Wonwoo , Wang Bin 
Published: June 2020

AbstractWe report herein the development of enantioselective and scalable α‐hydroxylation of 1‐indanone‐derived β‐keto esters by Zr(IV) complexes bearing readily available C2‐symmetric salan ligands and cumene hydroperoxide as an oxidant, affording synthetically valuable hydroxylation products in high yields (up to 99%) with excellent enantioselectivities (up to 99% ee) under mild reaction conditions. In mechanistic studies, we have shown that (1) a Zr(IV)‐salan complex was generated in situ as the active catalyst responsible for the chiral induction, (2) the transfer of the electrophilic fragment from cumene hydroperoxide to the Zr(IV)‐bound enolate was accompanied by a heterolytic O−O bond cleavage, and (3) the formation of hydrogen bond between the amine hydrogen atom(s) of the salan ligand and the hydroxy group of cumene hydroperoxide was significant for stabilizing the stereocontrolled transition state and improving the enantioselectivity.magnified image
Distinguishing Enantiomers by Tip‐Enhanced Raman Scattering: Chemically Modified Silver Tip with an Asymmetric Atomic Arrangement
Authors: Sukmanee Thanyada , Wongravee Kanet , Kitahama Yasutaka , Ekgasit Sanong , Itoh Tamitake , Pienpinijtham Prompong , Ozaki Yukihiro 
Published: June 2020

AbstractDiscrimination between enantiomers is achieved by tip‐enhanced Raman scattering (TERS) using a silver tip that is chemically modified by an achiral para‐mercaptopyridine (pMPY) probe molecule. Differences in the relative intensities of the pMPY spectra were monitored for three pairs of enantiomers containing hydroxy (−OH) and/or amino (−NH2) groups. The N: or N+−H functionality of the pMPY‐modified tip participates in hydrogen‐bond interactions with a particular molecular orientation of each chiral isomer. The asymmetric arrangement of silver atoms at the apex of the tip induces an asymmetric electric field, which causes the tip to become a chiral center. Differences in the charge‐transfer (CT) states of the metal‐achiral probe system in conjunction with the asymmetric electric field produce different enhancements in the Raman signals of the two enantiomers. The near‐field effect of the asymmetric electric field, which depends on the number of analyte functional groups capable of hydrogen‐bond formation, improves the degree of discrimination.
Glycoconjugated Metallohelices have Improved Nuclear Delivery and Suppress Tumour Growth In Vivo
Authors: Song Hualong , Allison Simon J. , Brabec Viktor , Bridgewater Hannah E. , Kasparkova Jana , Kostrhunova Hana , Novohradsky Vojtech , Phillips Roger M. , Pracharova Jitka , Rogers Nicola J. , Shepherd Samantha L. , Scott Peter 
Published: June 2020

AbstractMonosaccharides are added to the hydrophilic face of a self‐assembled asymmetric FeII metallohelix, using CuAAC chemistry. The sixteen resulting architectures are water‐stable and optically pure, and exhibit improved antiproliferative selectivity against colon cancer cells (HCT116 p53+/+) with respect to the non‐cancerous ARPE‐19 cell line. While the most selective compound is a glucose‐appended enantiomer, its cellular entry is not mainly glucose transporter‐mediated. Glucose conjugation nevertheless increases nuclear delivery ca 2.5‐fold, and a non‐destructive interaction with DNA is indicated. Addition of the glucose units affects the binding orientation of the metallohelix to naked DNA, but does not substantially alter the overall affinity. In a mouse model, the glucose conjugated compound was far better tolerated, and tumour growth delays for the parent compound (2.6 d) were improved to 4.3 d; performance as good as cisplatin but with the advantage of no weight loss in the subjects.
Isothiourea‐Catalyzed Acylative Kinetic Resolution of Tertiary α‐Hydroxy Esters
Authors: Qu Shen , Smith Samuel M. , Laina‐Martín Víctor , Neyyappadath Rifahath M. , Greenhalgh Mark D. , Smith Andrew D. 
Published: June 2020

AbstractA highly enantioselective isothiourea‐catalyzed acylative kinetic resolution (KR) of acyclic tertiary alcohols has been developed. Selectivity factors of up to 200 were achieved for the KR of tertiary alcohols bearing an adjacent ester substituent, with both reaction conversion and enantioselectivity found to be sensitive to the steric and electronic environment at the stereogenic tertiary carbinol centre. For more sterically congested alcohols, the use of a recently‐developed isoselenourea catalyst was optimal, with equivalent enantioselectivity but higher conversion achieved in comparison to the isothiourea HyperBTM. Diastereomeric acylation transition state models are proposed to rationalize the origins of enantiodiscrimination in this process. This KR procedure was also translated to a continuous‐flow process using a polymer‐supported variant of the catalyst.
Anisotropic Poisson Effect and Deformation‐Induced Fluorescence Change of Elastic 9,10‐Dibromoanthracene Single Crystals
Authors: Hayashi Shotaro , Ishiwari Fumitaka , Fukushima Takanori , Mikage Shohei , Imamura Yutaka , Tashiro Motomichi , Katouda Michio 
Published: June 2020

AbstractElastic organic crystals have attracted considerable attention as next‐generation flexible smart materials. However, the detailed information on both molecular packing change and macroscopic mechanical crystal deformations upon applied stress is still insufficient. Herein, we report that fluorescent single crystals of 9,10‐dibromoanthracene are elastically bendable and stretchable, which allows a detailed investigation of the deformation behavior. We clearly observed a Poisson effect for the crystal, where the short axes (b and c‐axes) of the crystal are contracted upon elongation along the long axis (a‐axis). Moreover, we found that the Poisson's ratios along the b‐axis and c‐axis are largely different. Theoretical molecular simulation suggests that the tilting motion of the anthracene may be responsible for the large deformation along the c‐axis. Spatially resolved photoluminescence (PL) measurement of the bent elastic crystals reveals that the PL spectra at the outer (elongated), central (neutral), and inner (contracted) sides are different from each other.
Electrochemical activity of 3D hairy hollow sphered Mn‐Cu‐Al layered hydroxide nanocomposites: A short survey on glucose analyte
Authors: Chandrasekaran Nivedhini Iswarya , Matheswaran Manickam 
Published: June 2020

AbstractA sensitive hollow shell‐based non‐enzymatic glucose sensor was developed using Mn‐Cu‐Al layered triple hydroxide on the surface of nickel foam (Mn‐Cu‐Al‐TH/NF). Mn‐Cu‐Al‐TH nanocomposites were prepared using a facile microwave‐assisted technique, and its hollow structure was created by continuous treatment with urea. The electrochemical activity of the Mn‐Cu‐Al‐TH/NF electrode was examined by cyclic voltammetric techniques. It was identified that the Mn‐Cu‐Al‐TH/NF electrode exhibited enhanced electrocatalytic activity towards glucose oxidation in alkaline medium (pH = 13), as compared with Mn‐Cu‐DH/NF and Mn‐H/NF electrodes. The electrocatalytic activity of the modified electrode under various pH values has been investigated. Under the optimized conditions, the electrochemical sensor exhibits a linear sensitivity towards glucose from 5 μM to 4 mM with a sensitivity of 2,108 μA mM−1 cm−2. Moreover, the glucose sensor demonstrated good selectivity, stability, fast response (<2 s), and repeatability. Our results suggest that Mn‐Cu‐Al‐TH hollow‐shelled layered triple hydroxide (LTH) nanocomposite could be a promising candidate for the construction of a nonenzymatic sensor.
The physiological characteristics of the basal microvilli microvessels in pancreatic cancers
Authors: Ma Lixiang , Han Xu , Gu Jichun , Li Ji , Lou Wenhui , Jin Chen , Saiyin Hexige 
Published: June 2020

AbstractPancreatic cancer (PC) is a highly lethal tumor with controversial high glucose uptake and hypomicrovascularity, and the hypomicrovasculature, which is considered to have poor perfusion, blocks the delivery of drugs to tumors. The preferential existence of a novel endothelial projection with trafficking vesicles in PCs, referring to basal microvilli, was described previously. However, the perfusion and nutrients delivering status of the basal microvilli microvessels are unknown. Here, we used the perfusion of fluorescently labeled CD31 antibody, lectin, and 2‐NBDG to autochthonous PC‐bearing mice, immunostaining, probe‐based confocal laser endoscopy and three‐dimensional (3D) reconstruction to study the nutrient trafficking, and perfusion status of the basal microvilli microvasculature in PC. Our data showed that the coperfusion of lectin and CD31 is an efficient way to show the microcirculation in most healthy organs. However, coperfusion with lectin and CD31 is inefficient for showing the microcirculation in PCs compared with that in healthy organs and immunostaining. This method does not reflect the nutrient trafficking status in the microvessels, especially in basal microvilli microvessels of PCs. In basal microvilli microvessels that were poorly labeled by lectin, we observed large vesicle‐like structures with 2‐NBDG preferentially located at the base of the basal microvilli or in basal microvilli, and there were long filopodia on the luminal surface of the human PC microvasculature. Our observations suggest that the PC microvasculature, especially basal microvilli microvessels, is well perfused and might be highly efficient in the trafficking of glucose or other nutrients, indicating that macropinocytosis might participate in the nutrient trafficking.
Differences in diagnosis, treatment, and survival rate of acute myeloid leukemia with or without disabilities: A national cohort study in the Republic of Korea
Authors: Kwon Jihyun , Kim So Young , Yeob Kyoung Eun , Han Hye Sook , Lee Ki Hyeong , Shin Dong Wook , Kim Yeon‐Yong , Park Jong Heon , Park Jong Hyock , Kawachi Ichiro 
Published: June 2020

AbstractWe analyzed the patterns of diagnosis, treatment, and prognoses of acute myeloid leukemia (AML) patients with and without disabilities. The data were collected from the National Disability Database, the Korean Central Cancer Registry, and the Korean National Health Insurance claim database. We built a cohort of 2 776 450 people with disabilities and a nondisabled cohort of 8 329 350 people who were selected at a ratio of 1:3 by matching age and sex. From this population, adult patients who were diagnosed with AML were analyzed. The number of patients with AML were 26.74 per 100 000 in people without disabilities and 20.39 per 100 000 in those with disabilities (P < .0001). The proportion of AML patients receiving chemotherapy and those of patients receiving transplants were significantly lower in the disabled population than that of nondisabled populations (71.2% vs 77.1%, P = .0031, and 17.5% vs 26.9%, P = .002). This trend was more pronounced in subgroups of communication disability and major internal organ disorder. The median survival was 10.8 months for patients with disabilities, which was significantly shorter than 17.1 months for those without a disability (P = .002). Individuals with disabilities have a low diagnosis rate of AML and undergo less active treatment, which results in inferior prognosis.
Counselling and psychotherapy post‐COVID‐19
Authors: Vostanis Panos , Bell Chance A. 
Published: June 2020

AbstractWe consider how the prolonged, complex and uncertain aftermath of the COVID‐19 crisis will present challenges and opportunities for counselling and psychotherapy. Increased mental strain on populations, individuals and professionals is likely to be compounded by further constraints in therapeutic resources. Nevertheless, emerging needs and priorities will offer ground for systems thinking in linking the application of a range of therapeutic frameworks, theories to address global challenges, integration of counselling and psychotherapy into new sectors, service models for the most vulnerable, use of digital approaches, support mechanisms for professionals and interdisciplinary research.
Analysis of Modified Nucleotide Aptamer Library Generated by Thermophilic DNA Polymerases
Authors: Percze Krisztina , Mészáros Tamás 
Published: June 2020

AbstractOne of the pivotal steps in aptamer selection is the amplification of target‐specific oligonucleotides by thermophilic DNA polymerases; it can be a challenging task if nucleic acids possessing modified nucleotides are to be amplified. Hence, the identification of compatible DNA polymerase and modified nucleotide pairs is necessary for effective selection of aptamers with unnatural nucleotides. We present an in‐depth study of using 5‐indolyl‐AA‐dUTP (TAdUTP) to generate oligonucleotide libraries for aptamer selection. We found that, among the eight studied DNA polymerases, only Vent(exo‐) and KOD XL are capable of adapting TAdUTP, and that replacing dTTP did not have a significant effect on the productivity of KOD XL. We demonstrated that water‐in‐oil emulsion PCR is suitable for the generation of aptamer libraries of modified nucleotides. Finally, high‐throughput sequence analysis showed that neither the error rate nor the PCR bias was significantly affected by using TAdUTP. In summary, we propose that KOD XL and TAdUTP could be effectively used for aptamer selection without distorting the sequence space of random oligonucleotide libraries.
Non‐Symmetrical Sterically Challenged Phenanthroline Ligands and Their Homoleptic Copper(I) Complexes with Improved Excited‐State Properties
Authors: Gimeno Lea , Blart Errol , Rebilly Jean‐Noël , Coupeau Marina , Allain Magali , Roisnel Thierry , Quarré de Verneuil Alexis , Gourlaouen Christophe , Daniel Chantal , Pellegrin Yann 
Published: June 2020

AbstractA strategy is presented to improve the excited state reactivity of homoleptic copper–bis(diimine) complexes CuL2+ by increasing the steric bulk around CuI whereas preserving their stability. Substituting the phenanthroline at the 2‐position by a phenyl group allows the implementation of stabilizing intramolecular π stacking within the copper complex, whereas tethering a branched alkyl chain at the 9‐position provides enough steric bulk to rise the excited state energy E00. Two novel complexes are studied and compared to symmetrical models. The impact of breaking the symmetry of phenanthroline ligands on the photophysical properties of the complexes is analyzed and rationalized thanks to a combined theoretical and experimental study. The importance of fine‐tuning the steric bulk of the N–N chelate in order to stabilize the coordination sphere is demonstrated. Importantly, the excited state reactivity of the newly developed complexes is improved as demonstrated in the frame of a reductive quenching step, evidencing the relevance of our strategy.
Boronate Ester‐Capped Helicates
Authors: Giraldi Erica , Depallens Adrien B. , Ortiz Daniel , Fadaei‐Tirani Farzaneh , Scopelliti Rosario , Severin Kay 
Published: June 2020

AbstractTriple‐stranded helicates were obtained by metal‐templated multicomponent reactions of bispyridyloxime ligands with arylboronic acids. The helicates feature two hexa‐coordinated MII ions (M=Fe, Zn, or Mn), which are embedded in a macrobicyclic ligand framework, and two arylboronate ester capping groups. The latter can be used to introduce functional groups such as pyridines, aldehydes, nitriles, and carboxylic acids in apical position. The functionalized helicates have the potential to be used as nanoscale building blocks for more complex assemblies, as evidenced by the synthesis of a 3 nm‐sized trianglimine.
Zinc Interactions with a Soluble Mutated Rat Amylin to Mimic Whole Human Amylin: An Experimental and Simulation Approach to Understand Stoichiometry, Speciation and Coordination of the Metal Complexes
Authors: Magrì Antonio , Tabbì Giovanni , Di Natale Giuseppe , La Mendola Diego , Pietropaolo Adriana , Zoroddu Maria Antonietta , Peana Massimiliano , Rizzarelli Enrico 
Published: June 2020

AbstractIslet amyloid polypeptide (IAPP) is a hormone co‐secreted with insulin and zinc from pancreatic β‐cells. To overcome the low solubility of human IAPP, we characterized zinc complexes species formed with 1) a mutated form of rat‐IAPP(1–37; R18 H) able to mimic the human IAPP, 2) the r‐IAPP(1–37) and the IAPP(1–8) fragment. Stoichiometry, speciation and coordination features of zinc(II) complexes were unveiled by ESI‐MS, potentiometry and NMR measurements combined with DFT and free‐energy simulations. Mononuclear species start to form around pH 6; Zn2+ binds both His18 and N‐amino terminus in rat‐IAPP(1–37; R18 H). The in silico study allows us to assess not only a structured turn compact domain in r‐IAPP(1–37) and r‐IAPP(1–37; R18 H) featured by a different free energy barrier for the transition from the compact to elongated conformation upon the coordination of Zn2+, but also to bring into light a coordination shell further stabilized by noncovalent interactions.
Impact of body mass index on procedural complications, procedure duration, and radiation dose in patients with atrial fibrillation undergoing radiofrequency ablation: A systematic review and meta‐analysis
Authors: Liu Menglu , Mei Kaibo , Liu Xiao , Zhao Yujie 
Published: June 2020

AbstractBackgroundThe association of body mass index (BMI) and procedure‐related factors in patients with atrial fibrillation (AF) after radiofrequency ablation (RFA) is still unclear.HypothesisBMI is associated with increased the radiation dose, procedure duration, and procedural complications.MethodsProspective studies assessing BMI and procedure duration, radiation dose, and procedural complications in patients with AF after RFA were identified through electronic searches of PubMed, Embase, and the Cochrane Library database.ResultsTen studies with 14 735 participants undergoing RFA were included. Procedure duration was significantly longer in patients with overweight or obesity than in patients with normal BMI, with a mean difference (MD) of 0.95. Patients with overweight and obesity were exposed to a larger radiation dose, with standard MD of 1.71 and 1.98, respectively. There was no significant association between overweight or obesity and the risk of procedural complications (RR of 0.91 for overweight, 1.01 for obesity, 0.89 for stage I obesity, 1.00 for stage II obesity, and 0.94 for stage III obesity). Further analysis showed there was no significant difference regarding stroke or transient ischemic attack (overweight, RR: 0.92; obesity, RR: 1.02); cardiac tamponade (overweight, RR: 0.92; obesity, RR: 1.02); groin hematoma (overweight, RR: 0.62; obesity, RR: 0.40); or pulmonary vein stenosis (overweight, RR: 0.49; obesity, RR: 0.40) among BMI groups.ConclusionBased on available evidence, we first showed that patients with overweight/obesity undergoing RFA experienced a significantly increased procedure duration and received a larger radiation dose than patients with normal BMI; however, there was no significant difference in procedural complications between patients with overweight/obesity and patients with normal BMI.
Electrocardiographic criteria which have the best prognostic significance in hypertensive patients with echocardiographic hypertrophy of left ventricle: 15‐year prospective study
Authors: Djordjevic Dragan B. , Tasic Ivan S. , Kostic Svetlana T. , Stamenkovic Bojana N. , Lovic Milan B. , Djordjevic Nikola D. , Koracevic Goran P. , Lovic Dragan B. 
Published: June 2020

AbstractBackgroundElectrocardiography is the first‐choice technique for detecting left ventricular hypertrophy in patients with arterial hypertension. It is necessary to know the probable outcome for every patient during the treatment, with the aim of improving cardiovascular event prevention.HypothesisCertain electrocardiographic criteria for left ventricular hypertrophy may predict outcomes of patients with left ventricular hypertrophy during a 15‐year follow‐up.MethodsFifteen‐year prospective study of 83 consecutive patients (53 male and 30 female; mean age 55.3 ± 8.1) with echocardiographic left ventricular hypertrophy (left ventricular mass index 170.3 ± 31.6 g/m2). Electrocardiographic left ventricular hypertrophy was determined by means of Gubner‐Ungerleider voltage, Lewis voltage, voltage of R wave in aVL lead, Lyon‐Sokolow voltage, Cornell voltage and Cornell product, voltage RV6and RV5ratio, Romhilt‐Estes score, Framingham criterion and Perugia criterion.ResultsOne or more composite events were registered in 32 (38.5%) patients during 15‐year follow‐up. Positive Lyon‐Sokolow score (17.6% vs. 47.3%;P < 0.05), Lewis voltage (9.8% vs. 21.9%;P < 0.05), Cornell voltage (15.7% vs. 37.5%;P < 0.05), and Cornell product (9.8% vs. 34.4%;P < 0.01) were more frequent in a group of patients with composite events. Odd ratio for Cornell product was 4.819 (95% CI 1.486‐15.627).ConclusionPatients with echocardiographic left ventricular hypertrophy who had positive Lewis voltage, Lyon‐Sokolow voltage, Cornell voltage, and Cornell product showed worse 15‐year outcome. The strongest predictor of cardiovascular events was positive result of Cornell product.
Geometrical Evolution and Formation of the Photoproduct in the Cycloreversion Reaction of a Diarylethene Derivative Probed by Vibrational Spectroscopy
Authors: Sotome Hikaru , Okajima Hajime , Nagasaka Tatsuhiro , Tachii Yuka , Sakamoto Akira , Kobatake Seiya , Irie Masahiro , Miyasaka Hiroshi 
Published: June 2020

AbstractThe geometrical evolution of the reactant and formation of the photoproduct in the cycloreversion reaction of a diarylethene derivative were probed using time‐resolved absorption spectroscopies in the visible to near‐infrared and mid‐infrared regions. The time‐domain vibrational data in the visible region show that the initially formed Franck‐Condon state is geometrically relaxed into the minimum in the excited state potential energy surface, concomitantly with the low‐frequency coherent vibrations. Theoretical calculations indicate that the nuclear displacement in this coherent vibration is nearly parallel to that in the geometrical relaxation. Time‐resolved mid‐infrared spectroscopy directly detected the formation of the open‐ring isomer with the same time constant as the decrease of the closed‐ring isomer in the excited state minimum. This observation reveals that no detectable intermediate, in which the population is accumulated, is present between the excited closed‐ring isomer and the open‐ring isomer in the ground state.
Unraveling the Origin of Differentiable ‘Turn‐On’ Fluorescence Sensing of Zn2+ and Cd2+ Ions with Squaramides
Authors: Lasitha P. , Dasgupta S. , Naresh Patwari G. 
Published: June 2020

AbstractA squaramide ring conjugated with Schiff‐bases decorated with hydroxy and methoxy functional groups differentially senses zinc and cadmium ions, which turn on the fluorescence. The feebly emitting free ligands light up in the presence of zinc and cadmium acetates, with the acetate ion playing a pivotal role as a conjugate anion. The selective and differentiable emission responses for zinc and cadmium ions make these ligands efficient multi‐analyte sensing agents. Furthermore, these ligands could be used to differentially sense zinc and cadmium ions even in aqueous environments. The NMR investigations reveal marginal differences in the binding of zinc and cadmium ions to the ligands, whereas density functional theory calculations suggest the different extent of ligand‐to‐metal charge transfer (LMCT) contributes to the differential behavior. Finally, comparison of the excited‐state dynamics of free ligand and the metal complexes reveal the appearance of longer lifetime (about 500–700 ps) component with complexation, due to rigidified molecular skeleton, thereby impeding the non‐radiative processes.