bluuebunny/crossref_metadata_2025_split huggingface dataset:
Setup of 4‐Prenylated Quinolines through Suzuki‐Miyaura Coupling for the Synthesis of Aurachins A and B
Authors: Stief Laura , Speicher Andreas 
Published: September 2021

AbstractA polyprenyl side chain could be introduced into the heterocyclic quinoline moiety through Suzuki‐Miyaura coupling of the corresponding quinoline‐N‐oxide with a polyprenyl boronic acid. This tool could be utilized for the synthesis of the natural product Aurachin B from the myxobacterium Stigmatella aurantiaca. This prenylated quinoline could then be transformed into the related Aurachin A through an epoxidation‐ring opening cascade.magnified image
Visible‐Light‐Induced Regioselective Deaminative Alkylation of Coumarins via Photoredox Catalysis
Authors: Tao Maoling , Wang An‐Jun , Guo Peng , Li Weipiao , Zhao Liang , Tong Jie , Wang Haoyang , Yu Yanbo , He Chun‐Yang 
Published: September 2021

Abstract3‐Alkylated coumarins have many applications in medicinal chemistry, however, methods access to such structures are still limited. Herein, we report a site‐selective photocatalytic deaminative alkylation of coumarins utilizing pyridinium‐activated aliphatic primary amines as alkylation reagents. The protocol was highlighted by its mild reaction conditions, operational simplicity, and broad functional group compatibility. Moreover, this strategy enables late‐stage modification of some pharmaceuticals and natural products, thus providing an appealing approach to valuable molecules in medicinal chemistry.magnified image
Solid Phase Synthesis of Thioether‐linked Peptide Macrocycles via Palladium‐Catalyzed Intramolecular S‐Arylation and S‐Alkenylation
Authors: Yang Peng , Zhang Chao , Li Bo , He Gang , Chen Gong 
Published: September 2021

AbstractA new protocol for synthesis of thioether‐linked peptide macrocycles via Pd‐catalyzed intramolecular S‐arylation and S‐alkenylation on solid phase is developed. The use of PEGA resin in mixed solvents of CH3CN and H2O is critical to suppress the undesired S‐arylation reactions with the XantPhos‐Pd‐G3 catalyst. Peptide macrocycles of varied ring size, composition, and with different thioether linkers can be prepared in moderate to good yield with one column chromatography purification.
Novel metabolic enzyme inhibitors designed through the molecular hybridization of thiazole and pyrazoline scaffolds
Authors: Sever Belgin , Türkeş Cüneyt , Altıntop Mehlika D. , Demir Yeliz , Akalın Çiftçi Gülşen , Beydemir Şükrü 
Published: September 2021

AbstractNew hybrid thiazolyl–pyrazoline derivatives (4a–k) were obtained through a facile and versatile synthetic procedure, and their inhibitory effects on the human carbonic anhydrase (hCA) isoforms I and II as well as on acetylcholinesterase (AChE) were determined. All new thiazolyl–pyrazolines showed activity at nanomolar levels as hCA I, hCA II, and AChE inhibitors, with KI values in the range of 13.35–63.79, 7.01–115.80, and 17.89–48.05 nM, respectively. 1‐[4‐(4‐Cyanophenyl)thiazol‐2‐yl]‐3‐(4‐piperidinophenyl)‐5‐(4‐fluorophenyl)‐2‐pyrazoline (4f) and 1‐(4‐phenylthiazol‐2‐yl)‐3‐(4‐piperidinophenyl)‐5‐(4‐fluorophenyl)‐2‐pyrazoline (4a) against hCAs and 1‐[4‐(4‐chlorophenyl)thiazol‐2‐yl]‐3‐(4‐piperidinophenyl)‐5‐(4‐fluorophenyl)‐2‐pyrazoline (4d) and 1‐[4‐(4‐nitrophenyl)thiazol‐2‐yl]‐3‐(4‐piperidinophenyl)‐5‐(4‐fluorophenyl)‐2‐pyrazoline (4b) against AChE were identified as highly potent inhibitors, superior to the standard drugs, acetazolamide and tacrine, respectively. Compounds 4a–k were also evaluated for their cytotoxic effects on the L929 mouse fibroblast (normal) cell line. Moreover, a comprehensive ligand–receptor interaction prediction was performed using the ADME‐Tox, Glide XP, and MM‐GBSA modules of the Schrödinger Small‐Molecule Drug Discovery Suite to elucidate the potential binding modes of the new hybrid inhibitors against these metabolic enzymes.
Intravenous injection of mesenchymal stem cell spheroids improves the pulmonary delivery and prolongs in vivo survival
Authors: Shimazawa Yoshihiko , Kusamori Kosuke , Tsujimura Mari , Shimomura Asuka , Takasaki Ryo , Takayama Yukiya , Shimizu Kazunori , Konishi Satoshi , Nishikawa Makiya 
Published: September 2021

AbstractBackgroundBecause of the excellent therapeutic potential, mesenchymal stem cells (MSCs) have been used as cell therapeutics for various diseases. However, the survival rate and duration of MSCs after transplantation are extremely low and short, respectively. To solve these problems, in this study, we prepared multicellular spheroids of MSCs and investigated their survival and function after intravenous injection in mice.Methods and ResultsThe murine adipose‐derived MSC line m17.ASC was cultured in agarose‐based microwell plates to obtain size‐controlled m17.ASC spheroids of an average diameter and cell number of approximately 170 μm and 1100 cells/spheroid, respectively. The intravenously injected m17.ASC spheroids mainly accumulated in the lung and showed a higher survival rate than suspended m17.ASC cells during the experimental period of 7 days. m17.ASC spheroids efficiently reduced the lipopolysaccharide‐induced increase in plasma concentrations of interleukin‐6 and tumor necrosis factor‐α.ConclusionsThese results indicate that spheroid formation improved the pulmonary delivery and survival of MSCs, as well as their therapeutic potential against inflammatory pulmonary diseases.
Synthesis and electrochemical characteristics of oligo[{3,4‐diphenyl‐1,1‐di(propan‐2‐yl)‐2,5‐silolene}‐co‐(diphenylsilylene)] for lithium‐ion secondary battery anodes
Authors: Jung Young Min , Park Young Tae 
Published: September 2021

AbstractThe co‐oligomerization of 2,5‐dibromo‐3,4‐diphenyl‐1,1‐di(propan‐2‐yl)‐silole (3) with dichlorodiphenylsilane was carried out using n‐butyllithium at −78°C to synthesize oligo[{3,4‐diphenyl‐1,1‐di(propan‐2‐yl)‐2,5‐silolene}‐co‐(diphenylsilylene)] (5) as yellowish‐white powder, with a mass‐average molar mass of 561, polydispersity of 1.01, λabs,max of 260 and 279 nm, λex,max of 296 nm, λem,max of 391 nm, and thermal stability up to 125°C without any weight loss. The rate performance obtained with oligomer 5 was superior to that obtained with monomer 3. The discharge and charge capacities with 5 were 1234 and 1263 mAhg−1, respectively, with Coulombic efficiency of 97.7% at the 100th cycle. Nyquist plots suggested that the resistance decreases gradually with repeated cycling.
Construction of circRNA‐based ceRNA network and its prognosis‐associated subnet of clear cell renal cell carcinoma
Authors: Zhang Yuwei , Zhang Yuchen , Feng Yangkun , Zhang Nan , Chen Saisai , Gu Chaoqun , Hu Lei , Sheng Jiayi , Xu Bin , Feng Ninghan 
Published: September 2021

AbstractCircular RNAs (circRNAs) are novel biomarkers of various cancers. CircRNAs can sponge miRNAs and regulate target mRNAs, which was called competing endogenous RNAs (ceRNA). This study was designed to identify circRNAs related to patients with clear cell renal cell carcinoma (ccRCC) and the first to select three independent Gene Expression Omnibus microarrays covering circRNAs, miRNAs, and mRNAs for multiple analyses. The data of clinical cases applied in our study were obtained from The Cancer Genome Atlas. We successfully conducted a circRNA/miRNA/mRNA ceRNA network related to ccRCC patients via R software and Cytoscape including 8 circRNAs, 6 miRNAs, and 49 mRNAs. The prognosis‐associated subnet covered 8 circRNAs, 6 miRNAs, and 22 mRNAs. Quantitative real‐time PCR was applied to measure our prediction in three renal cell lines and 23 pairs of tissues. Small interfering RNA targeting the back‐splice region of hsa_circ_0001167 was further implied to confirm the regulation. Ultimately, hsa_circ_0001167/hsa‐miR‐595/CCDC8 regulatory axis was identified in this study, which may serve as prognostic indicators. Lower levels of hsa_circ_0001167 and CCDC8 were potentially correlated with worse patient survival.
Optimization Strategies for the Anodic Phenol‐Arene Cross‐Coupling Reaction
Authors: Hielscher Maximilian , Oehl Elisabeth K. , Gleede Barbara , Buchholz Julian , Waldvogel Siegfried R. 
Published: September 2021

AbstractDehydrogenative phenol‐arene cross‐coupling by direct anodic oxidation is a promising alternative to reductive cross‐coupling, especially for construction of smaller molecules. The reaction pathway via phenoxyl radicals allows for unusual regioselectivity. Nevertheless, the numerous electrolysis parameters pose a challenge for optimization, as they determine the yield and selectivity of the reaction. Using design of experiments, we present optimization strategies for two example reactions to improve the space‐time yield. In particular, coupling reactions with 2,6‐dimethoxyphenol (syringol) were found to be very robust in the electrolysis at high current densities of up to 150 mA/cm2. Cyclic voltammetry was used to classify combinations of phenols and arenes, on the basis of which the various clusters were optimized. Based on this classification, various biaryls were synthesized and isolated in yields of up to 85 %.
Relationship between longitudinal changes in type‐2 inflammation, immunoglobulin E sensitization, and clinical outcomes in young asthmatics
Authors: Tsolakis Nikolaos , Jacinto Tiago , Janson Christer , Borres Magnus , Malinovschi Andrei , Alving Kjell 
Published: September 2021

AbstractBackgroundAsthma is a heterogeneous condition where biomarkers may be of considerable advantage in diagnosis and therapy monitoring. However, the changes in asthma biomarkers and immunoglobulin E (IgE) over the course of life has not been extensively investigated.ObjectiveTo study longitudinal changes in type‐2 inflammatory biomarkers, IgE, and clinical outcomes, and the association between these changes, in young asthmatics.MethodsAsthmatics (age 10–35 years, n = 253) were examined at baseline and at a follow‐up visit, 43 [23–65] (median [range]) months later. Subjects were analyzed using the multi‐allergen tests Phadiatop and fx5 (ImmunoCAP) and grouped based on the baseline allergen‐specific IgE antibody (sIgE) concentration: <0.10, 0.10–0.34, and ≥0.35 kUA/L. The relationship between changes (Δ values) in type‐2 biomarkers (individualized fraction of exhaled nitric oxide [FeNO%], blood eosinophil [B‐Eos] count, total IgE [tIgE] and sIgE, lung function [% predicted forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC)], and Asthma Control Test [ACT]) score were determined.ResultsAt follow up, FEV1 and FEV1/FVC had decreased (93.6% vs. 95.8%, and 93.4% vs. 94.7% of predicted, respectively [p < 0.001 both]), whereas ACT score had increased (21.6 vs. 20.6, p = 0.001). A significant decline in lung function was seen in subjects with sIgE ≥ 0.10 kUA/L, but not in those with undetectable sIgE (<0.10 kUA/L). Furthermore, tIgE and sIgE declined over time (p < 0.001 all) whereas FeNO% and B‐Eos count were not significantly changed. In univariate analysis, significant negative correlations between ∆B‐Eos count and ∆FeNO%, on one hand, and changes in lung function, on the other hand, were seen, and multivariate analysis showed an independent relationship between ΔFeNO%, and ΔFEV1 (p < 0.05) and ΔFEV1/FVC% (p < 0.01). Sex‐specific analysis showed that the independent association between ΔFeNO%, and ΔFEV1 remained only in females (p = 0.005), and there was a significant interaction with sex (p = 0.02).ConclusionIn young asthmatics, IgE levels declined over 43 months, whereas FeNO and B‐Eos remained unchanged. In spite of improved asthma control, an accelerated lung function decline was seen in patients with detectable sIgE at baseline, and the decline correlated with changes in type‐2 biomarkers. Particularly, the increase in individualized FeNO associated independently with decline in FEV1 in females.
A Versatile Compact Parahydrogen Membrane Reactor
Authors: TomHon Patrick M. , Han Suyong , Lehmkuhl Sören , Appelt Stephan , Chekmenev Eduard Y. , Abolhasani Milad , Theis Thomas 
Published: September 2021

AbstractWe introduce a Spin Transfer Automated Reactor (STAR) that produces continuous parahydrogen induced polarization (PHIP), which is stable for hours to days. We use the PHIP variant called signal amplification by reversible exchange (SABRE), which is particularly well suited to produce continuous hyperpolarization. The STAR is operated in conjunction with benchtop (1.1 T) and high field (9.4 T) NMR magnets, highlighting the versatility of this system to operate with any NMR or MRI system. The STAR uses semipermeable membranes to efficiently deliver parahydrogen into solutions at nano to milli Tesla fields, which enables 1H, 13C, and 15N hyperpolarization on a large range of substrates including drugs and metabolites. The unique features of the STAR are leveraged for important applications, including continuous hyperpolarization of metabolites, desirable for examining steady‐state metabolism in vivo, as well as for continuous RASER signals suitable for the investigation of new physics.
A 1‐Hydroxy‐1H‐imidazole ESIPT Emitter Demonstrating anti‐Kasha Fluorescence and Direct Excitation of a Tautomeric Form
Authors: Shekhovtsov Nikita A. , Nikolaenkova Elena B. , Berezin Alexey S. , Plyusnin Victor F. , Vinogradova Katerina A. , Naumov Dmitry Yu. , Pervukhina Natalia V. , Tikhonov Alexsei Ya. , Bushuev Mark B. 
Published: September 2021

AbstractThe ability of 1‐hydroxy‐1H‐imidazoles to exist in the form of two prototropic tautomers, the N‐hydroxy and the N‐oxide forms, can be utilized in the design of new types of ESIPT‐fluorophores (ESIPT=excited state intramolecular proton transfer). Here we report the first example of 1‐hydroxy‐1H‐imidazole‐based ESIPT‐fluorophores, 1‐hydroxy‐5‐methyl‐2,4‐di(pyridin‐2‐yl)‐1H‐imidazole (HL), featuring a short intramolecular hydrogen bond O−H⋅⋅⋅N (O⋅⋅⋅N 2.56 Å) as a pre‐requisite for ESIPT. The emission of HL originates from the anti‐Kasha S2→S0 fluorescence in the N‐oxide form as a result of a large S2–S1 energy gap slowing down the S2→S1 internal conversion. Due to an energy barrier between the N‐hydroxy and N‐oxide forms in the ground state, the HL molecules can be trapped and photoexcited in the N‐oxide form leading to the Stokes shift of ca. 60 nm which is the smallest among known ESIPT‐fluorophores.
Multidomain modeling of nonlinear electromagnetic circuits using wave digital filters
Authors: Giampiccolo Riccardo , Bernardini Alberto , Gruosso Giambattista , Maffezzoni Paolo , Sarti Augusto 
Published: September 2021

SummaryAccurate models of electromagnetic systems can be derived by coupling electric and magnetic equivalent circuits together. The different nature of such physical domains constitutes a big challenge that puts a continuous strain on software simulators. To face this problem, a simulation approach based on Wave Digital Filters (WDFs) is proposed in this manuscript. The method is employed to solve nonlinear electromagnetic systems containing complex magnetic equivalent circuits while maintaining the modularity of the electric and magnetic subsystems. The nonlinearities can be locally handled, enabling the possibility to choose a dedicated model for each one of them. The proposed algorithm is a hierarchical generalization of the Scattering Iterative Method, which has shown, over the past few years, promising performance for the simulation of large nonlinear circuits. In addition, the method constitutes a further step towards the development of novel general‐purpose circuit simulators based on WDF principles. In a comparison with mainstream circuit simulation software, the proposed approach turns out to be considerably faster and thus particularly promising for parametric analyses of electromagnetic systems.
Compact closed‐slot eight‐antenna system for 5G laptops with a metal back cover
Authors: Chen Shu‐Chuan , Zhu Jia‐Le , Hsu Chung‐I G. 
Published: September 2021

SummaryThis paper presents the design of a compact closed‐slot sub‐6‐GHz dual‐band eight‐antenna system on a 5G laptop with a metal back cover. The antenna system is installed in a 277 × 2 mm2 clearance area that is 3 mm below the upper edge of the metal back cover of the laptop. Each single closed‐slot antenna element measures 32 × 2 mm2 and features an inverted‐C feeding section and a crossover path consisting of a meandered section and a series chip capacitor. The crossover path can help generate a resonance mode at high frequencies while adjusting the frequency location of the low‐frequency mode, allowing the closed‐slot antenna to support the 3300‐ to 3600‐ and 4800‐ to 5000‐MHz dual‐band operation required for sub‐6‐GHz 5G. The eight closed‐slot antenna elements are oriented in the same direction and aligned in the same axis with a 3‐mm separation between any two adjacent antenna elements. Without the help of any isolation elements, the resultant eight‐element multi‐input multi‐output (MIMO) antenna system possesses measured isolations of larger than 10 dB. The envelope correlation coefficients (ECCs) calculated from the measured complex radiation patterns are all less than 0.105, and the measured antenna efficiencies are over 40%. These results indicate that the proposed MIMO antenna system is ideal for use in laptop devices with a metal back cover and a large screen‐to‐body ratio.
Endoscopic diagnosis of chronic diarrhea
Authors: Kinoshita Yoshikazu , Ariyoshi Ryusuke , Fujigaki Seiji , Tanaka Katsuhide , Morikawa Teruhisa , Sanuki Tsuyoshi 
Published: September 2021

AbstractThe prevalence of chronic diarrhea in the general population is reported to be 4%–5%. Since various pathological conditions cause diarrheal symptoms, etiological diagnosis of chronic diarrhea is difficult in many cases. Medical history taking, physical examinations, and laboratory testing are not adequately sensitive or specific, thus a colonoscopic investigation is frequently employed for etiological evaluation. However, for cases with non‐bloody chronic diarrhea, the diagnostic yield of a colonoscopy procedure is reported to be not high enough. Furthermore, endoscopically identifiable findings are not adequately specific for the diagnosis of diarrheal disease, except for inflammatory bowel disease, while microscopic colitis, amyloidosis, eosinophilic gastroenteritis, celiac disease, and bile acid diarrhea are difficult to definitively diagnose using endoscopic findings. Thus, a histopathological examination of biopsy samples obtained with endoscopy is critically important. Endoscopists should consider obtaining biopsy samples from even normal‐appearing gastrointestinal mucosa for chronic diarrhea diagnosis.
Experimental verification of bidirectional modular multilevel cascaded converter suitable for applying 120‐degree discontinuous pulse width modulation maximum
Authors: Oi Kazunobu , Urushibata Shota , Tadano Yugo , Sato Yukihiko 
Published: September 2021

AbstractModular multilevel cascaded converters (MMCCs) have advantages in the application of high or medium voltage without transformers. They can also generate high‐quality voltage with fewer harmonics. Their unique merits make them leading technology candidates for high/medium voltage applications. However, a concern still exists that the number of parts may be increased. In this study, an MMCC topology using high‐voltage IGBT (HV‐IGBT) with snubber capacitor connected in parallel as a cell module arm is proposed, by which the number of cells can be halved and conduction loss can be significantly reduced owing to the output current flowing through the HV‐IGBT in one‐third of the cycle. Meanwhile, the proposed control stratagem can control the cell capacitor voltage, suppress the HV‐IGHT surge voltage, and avoid short‐circuiting of the snubber capacitor by circulating current. This study reports the evaluation results of capacitors and the experimental results of bidirectional active power conversion operation.
Limitations and Benefits of MAX Phases in Electroanalysis
Authors: Tesař Jan , Muñoz Jose , Pumera Martin 
Published: September 2021

AbstractMAX phases are a group of layered 2D materials made of early transition metal, A‐group element (e.g., Al, Sn or Si), and C or N. These nanolaminated carbides and nitrides combine many attractive characteristics of metals and ceramics such as excellent electric and thermal conductivity and high chemical resistance. Although MAX phases have shown promising electrochemical results in the field of energy conversion, their use for electroanalytical approaches is nowadays an unexplored field. Herein, the potential use of MAX phases for electroanalytical approaches has been investigated. For this aim, seven different MAX phases (Cr2AlC, Mo2AlC, Ta2AlC, Ti2AlN, Ti2SnC, Ti3AlC2, Ti3SiC2, and V2AlC) have been drop‐casted upon a conventional glassy‐carbon electrode and tested at different pH media, also providing their potential towards the determination of different analytes. Overall, our findings elucidate the limitations and benefits of using MAX phases for electroanalysis, demonstrating that a proper combination of both MAX phases and electrolyte media is a must to direct efficient performances as electrode for electroanalysis. Accordingly, this work provides new knowledge about the electrochemical behaviour of MAX phases and their potential in the field of electronic devices.
The mechanism exploration of the non‐colonic toxicity and obesity inhibition of food‐grade κ‐carrageenan by transcriptome
Authors: Zhang Hui , Cao Wanxiu , Liu Fang , Gao Yuan , Chang Yaoguang , Xue Changhu , Tang Qingjuan 
Published: September 2021

AbstractPrevious study has suggested the colonic nontoxicity and obesity inhibition of food‐grade κ‐carrageenan in obese mice. Further study using transcriptome is important to provide further understanding on the gene expressions of inflammation and obesity. Here, the obese mice without any treatment (HFD) or with 5% food‐grade κ‐carrageenan diet intervention (H5%) were used to perform colonic transcriptome sequencing. The results showed that genes involved in the inflammatory pathways or tight junction protein encoding were not significantly dysregulated by 5% carrageenan. However, the expression of lipid metabolism genes meaningfully changed as evidenced by the decreased gene levels of adipocytokines, lipogenesis, lipid absorption and transport, and the increased adipolysis and oxidation. In addition, the carrageenan metabolism experiments by toluidine blue (TB) staining of colon and high‐performance size exclusion chromatography (HPSEC) of feces supernatant showed that the food‐grade κ‐carrageenan was not absorbed or significantly degraded in the digestive tract of obese mice. Hence, the fact that food‐grade κ‐carrageenan was not significantly metabolized by the organism and did not cause obvious dysregulation of colonic inflammatory genes provided evidences for its noncolonic toxicity in obese mice. An anti‐obesity potential of food‐grade κ‐carrageenan was probably mediated by the regulation of lipids metabolism‐related genes.
Use of high‐frequency data to evaluate the performance of dynamic hedging strategies
Authors: Lai Yu‐Sheng 
Published: September 2021

AbstractThe hedging performance results of generalized autoregressive conditional heteroskedasticity models are mixed; we address this herein by adopting an asymptotic setting to determine the relative performance of competing hedge ratios. The proxy variable is constructed through precise realized measures rather than through noisy squared returns because the substitution of the latent true hedged portfolio variance with a noisy proxy renders the loss function incapable of ranking forecasts consistently. The merits of allowing some features in modeling the spot–futures distribution are assessed. Empirical comparisons suggest that hedgers may favor the wrong model when the quality of the proxy variable deteriorates.