bluuebunny/crossref_metadata_2025_split huggingface dataset:
Der Sonnenblumen‐Trypsin‐Inhibitor 1 (SFTI‐1) in der Chemie und Biologie
Authors: de Veer Simon J. , White Andrew M. , Craik David J. 
Published: July 2020

AbstractNatürlich vorkommende zyklische Peptide haben sich als wichtige Inspirationsquelle für die Weiterentwicklung des modernen pharmazeutischen Designs und der Synthesechemie erwiesen. Der Schwerpunkt dieses Aufsatzes liegt auf dem Sonnenblumen‐Trypsin‐Inhibitor 1 (SFTI‐1), einem der kleinsten in der Natur vorkommenden disulfidverbrückten zyklischen Peptide. SFTI‐1 hat einen ungewöhnlichen Biosyntheseweg, der mit einem Albuminvorläufer mit doppeltem Verwendungszweck beginnt und mit der Produktion eines Serinproteaseinhibitors mit hoher Affinität endet, der mit anderen viel größeren Inhibitoren konkurriert. Die Untersuchung der molekularen Grundlagen für die starre Struktur und anpassungsfähige Funktion von SFTI‐1 hat zu Denkanstößen geführt, die nun in verschiedenen Bereichen erste Resultate zeitigen. Hier untersuchen wir diese Anwendungen, um das wachsende Potenzial von SFTI‐1 als vielseitiges Templat für das Inhibitoren‐Engineering, als prototypisches Peptid zur Untersuchung von Inhibitormechanismen, als stabiles Gerüst für die Aufpfropfung bioaktiver Peptide und als Modellpeptid zur Bewertung peptidmimetischer Motive und Plattformtechnologien hervorzuheben.
Homologation of the Fischer Indolization: A Quinoline Synthesis via Homo‐Diaza‐Cope Rearrangement
Authors: Gerosa Gabriela Guillermina , Schwengers Sebastian Armin , Maji Rajat , De Chandra Kanta , List Benjamin 
Published: July 2020

AbstractWe disclose a new Brønsted acid promoted quinoline synthesis, proceeding via homo‐diaza‐Cope rearrangement of N‐aryl‐N′‐cyclopropyl hydrazines. Our strategy can be considered a homologation of Fischer's classical indole synthesis and delivers 6‐membered N‐heterocycles, including previously inaccessible pyridine derivatives. This approach can also be used as a pyridannulation methodology toward constructing polycyclic polyheteroaromatics. A computational analysis has been employed to probe plausible activation modes and to interrogate the role of the catalyst.
Sunflower Trypsin Inhibitor‐1 (SFTI‐1): Sowing Seeds in the Fields of Chemistry and Biology
Authors: de Veer Simon J. , White Andrew M. , Craik David J. 
Published: July 2020

AbstractNature‐derived cyclic peptides have proven to be a vast source of inspiration for advancing modern pharmaceutical design and synthetic chemistry. The focus of this Review is sunflower trypsin inhibitor‐1 (SFTI‐1), one of the smallest disulfide‐bridged cyclic peptides found in nature. SFTI‐1 has an unusual biosynthetic pathway that begins with a dual‐purpose albumin precursor and ends with the production of a high‐affinity serine protease inhibitor that rivals other inhibitors much larger in size. Investigations on the molecular basis for SFTI‐1′s rigid structure and adaptable function have planted seeds for thought that have now blossomed in several different fields. Here we survey these applications to highlight the growing potential of SFTI‐1 as a versatile template for engineering inhibitors, a prototypic peptide for studying inhibitory mechanisms, a stable scaffold for grafting bioactive peptides, and a model peptide for evaluating peptidomimetic motifs and platform technologies.
Enhancement in Li+/Mg2+ separation from salt lake brine with PDA–PEI composite nanofiltration membrane
Authors: Ashraf Muhammad Awais , Wang Junfeng , Wu Baichun , Cui Penglei , Xu Baohua , Li Xingchun 
Published: July 2020

AbstractExtraction of lithium from high Mg2+/Li+ ratio salt lake brine with the nanofiltration (NF) membrane is significantly challenging. Interfacial polymerization was utilized for the facile modification of NF membranes with polydopamine (PDA) and polyethylenimine (PEI) to enhance lithium separation efficiency. Comparing permeability and salts rejection (Li+ and Mg2+) of three NF membranes before and after PDA/PEI deposition, it was observed that separation efficiency was not only dependent on steric hindrance but also affected by Donnan exclusion mechanism. In the case of NF270 membrane after facile polymerization, due to small pore size distribution and low charge density confirmed by zeta potential measurements, Li+ permeability was reached about 95% at a flux of 21.33 L·m−2·h−1. Although with the DK membrane, separation factor SFLi/Mg was also increased up to 60 after modification, the pore narrowing effect significantly decreased lithium permeability and flux. Experimental results showed that facile modification not only enhanced stability and hydrophilicity but also reduced the high Mg2+/Li+ ratio from 30 to 4.1 in single‐stage separation.
A comprehensive study on Plantago ovata/PVA biocompatible nanofibers: Fabrication, characterization, and biological assessment
Authors: Allafchian Ali Reza , Kalani Sahar , Golkar Pooran , Mohammadi Hassan , Jalali Seyed Amir Hossein 
Published: July 2020

AbstractIn this study, a biocompatible nanofiber is fabricated using Plantago ovata mucilage (POM) combined with polyvinyl alcohol (PVA), which is considered as a non‐toxic polymer. High quality nanofibers were produced by controlling the electrospinning parameters after selecting an appropriate solvent for the POM/PVA combination (12% PVA and 3% POM). Electrospinning parameters, including high voltage, distance from collector to tip, feed rate and POM to PVA proportion were optimized following preparation of an aqueous POM/PVA solution. Using the results of scanning electron microscopy, the optimized electrospinning conditions for producing POM/PVA nanofibers were determined (high voltage = 18 kV, distance = 15 cm, feed rate = 0.125 ml/hr, PMM/PVA = 50/50) and uniform nanofibers with an average diameter of 250 nm were produced. The POM/PVA nanofiber sample was evaluated by determining the mechanical strength, characterization of produced nanofiber morphology, and investigating the cell viability by applying MTT assay. The bands for both POM and PVA from FTIR results showed that the samples remained stable. The tensile strength results showed that blending POM with PVA solution enhanced the Young's modulus by factor of 3.2 (0.2 MPa to 0.64 MPa). The MTT analysis on POM/PVA cell lines proved that the produced nanofiber considerably enabled the cellular proliferation. Enhancement in these analysis indicated how POM‐based nanofibers is a promising scaffold for cell culture, drug delivery systems and food additives.
Synergistic toughening and electrical functionalization of an epoxy usingMWCNTsand silane‐ /plasma‐activated basalt fibers
Authors: Quan Dong , Moloney Peter , Carolan Declan , Abourayana Hisham , Ralph Calvin , Ivankovic Alojz , Dowling Denis , Murphy Neal 
Published: July 2020

AbstractThis work studied the effects of adding short basalt fibers (BFs) and multi‐walled carbon nanotubes (MWCNTs), both separately and in combination, on the mechanical properties, fracture toughness, and electrical conductivity of an epoxy polymer. The surfaces of the short BFs were either treated using a silane coupling agent or further functionalized by atmospheric plasma to enhance the adhesion between the BFs and the epoxy. The results of a single fiber fragmentation test demonstrated a significantly improved BF/epoxy adhesion upon applying the plasma treatment to the BFs. This resulted in better mechanical properties and fracture toughness of the composites containing the plasma‐activated BFs. The improved BF/epoxy adhesion also affected the hybrid toughening performance of the BFs and MWCNTs. In particular, synergistic toughening effects were observed when the plasma‐activated BFs/MWCNTs hybrid modifiers were used, while only additive toughening effects occurred for the silane‐sized BFs/MWCNTs hybrid modifiers. This work demonstrated a potential to develop strong, tough, and electrically conductive epoxy composites by adding hybrid BF/MWCNT modifiers.
Autoantibodies to Malondialdehyde–Acetaldehyde Are Detected Prior to Rheumatoid Arthritis Diagnosis and After Other Disease Specific Autoantibodies
Authors: Mikuls Ted R. , Edison Jess , Meeshaw Elizabeth , Sayles Harlan , England Bryant R. , Duryee Michael J. , Hunter Carlos D. , Kelmenson Lindsay B. , Kay Moss Laura , Feser Marie L. , Wagner Brandie , Parish Mark C. , Deane Kevin D. , Thiele Geoffrey M. 
Published: July 2020

ObjectiveTo examine serum autoantibodies to malondialdehyde–acetaldehyde (MAA) prior to rheumatoid arthritis (RA) diagnosis.MethodsConcentrations of anti‐MAA antibody isotypes, anti–cyclic citrullinated peptide 2 (anti–CCP‐2), and IgM rheumatoid factor (IgM‐RF) were evaluated before and after RA diagnosis in samples from cases (n = 214) and controls (n = 210). The timing of elevations in autoantibody concentrations relative to RA diagnosis was explored using separate mixed models for each antibody and/or isotype. Associations between prediagnosis autoantibody concentrations in RA patients were examined using mixed effects linear regression models.ResultsConcentrations of IgG (log2 difference 0.34) and IgA (log2 difference 0.43) anti‐MAA antibodies in RA patients diverged from controls at 3.0 years and 2.3 years prior to diagnosis, respectively (P < 0.05 for both). There was no evidence of case–control divergence for IgM anti‐MAA antibody concentration. Anti–CCP‐2 and IgM‐RF concentrations diverged between RA patients and controls beginning at 17.6 years and 7.2 years prior to RA diagnosis, respectively. All 3 anti‐MAA antibody isotypes (IgA, IgM, and IgG) were significantly associated with anti–CCP‐2 antibody and RF concentrations prior to diagnosis (β = 0.22–0.27 for IgM‐RF; β = 0.44–0.93 for anti–CCP‐2) (P < 0.001).ConclusionIgG and IgA anti‐MAA autoantibodies are elevated prior to RA diagnosis but appear later in the preclinical course than anti–CCP‐2 or RF. These findings suggest that MAA formation and anti‐MAA immune responses could play a role in the transition from subclinical autoimmunity to clinically apparent arthritis.
Immunodetection of urinary C‐terminal telopeptide fragment of type II collagen: An osteoarthritis biomarker analysis
Authors: Wang Shuwei , Su Shanlin , Yu Chunyun , Gopinath Subash C. B. , Yang Zhiquan 
Published: July 2020

AbstractThe urinary C‐terminal telopeptide fragment of type II collagen (uCTX‐II) has been reported as the efficient blood‐based biomarker for osteoarthritis, which affects knees, hands, spine, and hips. This study reports a sensing strategy with antibody‐conjugated gold nanoparticles (GNP) on an interdigitated electrode (IDE) to determine uCTX‐II. The GNP–antibody complex was chemically immobilized on the IDE surface through the amine linker. uCTX‐II was determined by monitoring the alteration in current upon interacting the GNP‐complexed antibody. This strategy was improved the detection by attracting higher uCTX‐II molecules, and the detection limit falls in the range of 10–100 pM with an acceptable regression value [y = 0.6254x − 0.4073, R² = 0.9787]. The sensitivity of the detection was recognized at 10 pM. Additionally, upon increasing the uCTX‐II concentration, the current changes were increased in a linear fashion. Control detection with nonimmune antibody and control protein do not increase the current level, confirming the specific detection of uCTX‐II. This method of detection helps in diagnosing osteoarthritis and its follow‐up treatment.
Cover Image, Volume 14, Issue 4
Authors: Brandt Kristin L. , Wooley Robert J. , Geleynse Scott C. , Gao Johnway , Zhu Junyong , Cavalieri Ralph P. , Wolcott Michael P. 
Published: July 2020

The cover image is based on the Modeling and Analysis Article Impact of co‐product selection on techno‐economic analyses of alternative jet fuel produced with forest harvest residuals by Kristin Brandt et al., https://doi.org/10.1002/bbb.2111.
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An efficient method for the determination of enantiomeric purity of racemic amino acids using micellar chromatography, a green approach
Authors: Alwera Shiv , Alwera Vijay , Sehlangia Suman 
Published: July 2020

AbstractA simple, sensitive and green micellar liquid chromatographic method (RP‐HPLC) was developed for enantioseparation of four racemic amino acids, namely, (RS)‐selenomethionine, (RS)‐methionine, (RS)‐cysteine and (RS)‐penicillamine. An aqueous solution of sodium dodecyl sulfate and Brij‐35 was prepared and used as mobile phase for HPLC analysis. Activated esters of (S)‐ibuprofen, (S)‐ketoprofen and (S)‐levofloxacin were synthesized by reacting them with N‐hydroxybenzotriazole. These esters were characterized by UV, IR, 1HNMR, HRMS and elemental analysis. These chiral reagents (activated esters) were used for the synthesis of diastereomeric derivatives of the chosen amino acids. The diastereomeric derivatives were separated on a C18 column by micellar liquid chromatography. Chromatographic conditions were optimized by varying concentration of surfactant in aqueous solution, and by varying the concentration and pH of the buffer. The green assessment score was calculated for the developed method (78, an excellent green method score). In addition, density functional theory calculations were performed, using Gaussian 09 rev. A.02 and hybrid density functional B3LYP with a 6‐31G* basis set program, in order to develop lowest energy optimized structures of diastereomeric derivatives. The method was validated according to International Conference on Harmonization guidelines and the retention factor (k), selectivity factor (α), resolution factor (RS) and limit of detection (0.295 ng ml−1) and limit of quantification (0.896 ng ml−1) were calculated.
Transient effects of multi‐infusion ketamine augmentation on treatment‐resistant depressive symptoms in patients with treatment‐resistant bipolar depression – An open‐label three‐week pilot study
Authors: Zhuo Chuanjun , Ji Feng , Tian Hongjun , Wang Lina , Jia Feng , Jiang Deguo , Chen Ce , Zhou Chunhua , Lin Xiaodong , Zhu Jingjing 
Published: July 2020

AbstractIntroductionWhile the psychiatric benefits of ketamine have been verified through clinical trials, there is limited information about ketamine augmentation in patients with treatment‐resistant bipolar depression (TRBPD). Hence, in the present study, we investigate the therapeutic efficacy and functional brain alterations associated with multi‐infusion ketamine augmentation in patients with TRBPD.MethodsThe present three‐week study included 38 patients with TRBPD, all of whom received a series of nine ketamine injections over the study period. The Hamilton Depression Rating Scale (HAMD) was used to assess the effects of multi‐infusion ketamine combined with mood stabilizers. Brain function was evaluated by global functional connectivity density (gFCD).ResultsAdjunctive treatment with multiple infusions of ketamine, when combined with a mood stabilizer, could effectively alleviate depressive symptoms for one week, yet the symptoms began to relapse during the second week. Functional brain alterations were detected via gFCD. Specifically, gFCD reductions were mainly found in the bilateral insula, right caudate nucleus, and bilateral inferior frontal gyrus, while increased gFCD was mainly located in the bilateral postcentral gyrus, subgenual anterior cingulate cortex, bilateral thalamus, and cerebellum. Although gFCD alterations were sustained for up to three weeks after the first ketamine infusion, the antidepressant effects of ketamine augmentation sharply declined from the end of the second week of treatment.ConclusionsMulti‐infusion ketamine augmentation can rapidly alleviate depressive symptoms in patients with TRBPD. The clinical effects were primarily visible in the first week after treatment and partially sustained for two weeks; however, the therapeutic effects and related functional brain alterations sharply decreased from the end of the second week. Based on these findings, we demonstrated that the clinical efficacy and functional brain alterations induced by ketamine augmentation are transient.
The Ubiquitin Enigma: Progress in the Detection and Chemical Synthesis of Branched Ubiquitin Chains
Authors: Hua Xiao , Chu Guo‐Chao , Li Yi‐Ming 
Published: July 2020

AbstractUbiquitin chains with distinct topologies play essential roles in eukaryotic cells. Recently, it was discovered that multiple ubiquitin units can be ligated to more than one lysine residue in the same ubiquitin to form diverse branched ubiquitin chains. Although there is increasing evidence implicating these branched chains in a plethora of biological functions, few mechanistic details have been elucidated. This concept article introduces the function, detection and chemical synthesis of branched ubiquitin chains; and offers some future perspective for this exciting new field.
Spontaneous thrombosis of a transcatheter aortic valve replacement‐induced aortic root pseudoaneurysm
Authors: Costa Giulia , Ihlemann Nikolaj , Søndergaard Lars , De Backer Ole 
Published: July 2020

AbstractAortic annulus rupture or aortic root perforation is a rare complication of transcatheter aortic valve replacement (TAVR), requiring emergent cardiac surgery and carrying a high intraoperative mortality. Few cases can be managed conservatively, provided a strict clinical follow‐up. This study describes the case of a 78‐year‐old patient with a degenerated bicuspid aortic valve stenosis who presented with a late aortic root perforation following TAVR, which was successfully managed applying a “watchful waiting” approach. Cardiac computed tomography imaging played a pivotal role in the diagnosis and subsequent decision on treatment and clinical follow‐up.
Identification of Iron Carbides in Fe(−Na−S)/α‐Al2O3 Fischer‐Tropsch Synthesis Catalysts with X‐ray Powder Diffractometry and Mössbauer Absorption Spectroscopy
Authors: Paalanen Pasi P. , van Vreeswijk Sophie H. , Dugulan A. Iulian , Weckhuysen Bert M. 
Published: July 2020

AbstractIn Fe‐based Fischer‐Tropsch Synthesis (FTS), the Fe carbides form under the carburizing H2 : CO reaction atmosphere providing the active phases for hydrocarbon synthesis. H2 reduced Fe(−Na−S)/α‐Al2O3 catalyst materials, with and without Na−S promotion, were carburized under CO at 240–440 °C to form Fe carbides. X‐ray Powder Diffractometry (XRPD) with Rietveld Quantitative Phase Analysis (R‐QPA) and Mössbauer Absorption Spectroscopy (MAS) were used to identity and quantify the formed Fe carbide phases. The Fe carbides formed in order of increasing temperature are ϵ‐Fe3C, η‐Fe2C, χ‐Fe5C2 and θ‐Fe3C. θ‐Fe7C3 and a distorted χ‐Fe5C2 phase are formed at 25 bar CO (340 °C) from a Fe oxide precursor. Fe carbide formation was unaffected by Na−S addition, but it did increase Fe oxidation (≤290 °C) and preferred formation of χ‐Fe5C2 over θ‐Fe3C phase (≥390 °C). The results unify the often ambiguous Fe carbide identification and nomenclature and specify the role of Na−S in the carburization process.
Enantioselective synthesis of cyclic and linear diamines by imine cycloadditions
Authors: Chang Tsung‐Che , Pradipta Ambara R. , Tanaka Katsunori 
Published: July 2020

AbstractImine is one of the most versatile functional groups in chemistry and biochemistry fields. Although many biochemical reactions involve imine formation, the inherently unstable property of N‐alkyl‐α,β‐unsaturated imines still hindered their utilization in organic synthesis. In this article, we described that the N‐alkyl‐α,β‐unsaturated imines, which prepared from alkylamines and acrolein, could smoothly react through [4 + 4] cycloaddition to give eight‐membered diazacyclooctane derivatives in excellent yields. Under a similar condition, in the presence of formaldehyde, the [4 + 2] and [4 + 2 + 2] cycloadditions could lead to the formation of six‐membered hexahydropyrimidine or eight‐membered triazacyclooctanes, depending on the substituent of aldehydes. Moreover, an easy functional group manipulation of the cyclic products obtained from these cycloadditions can provide variously substituted chiral linear diamines. We can utilize these novel reactivities to reveal the unknown and essential properties of many biological processes that involve N‐alkyl‐unsaturated imines.
Construction of a Nano‐rectangular Zn(II)‐Yb(III) Complex with Near‐Infrared Luminescent Response towards Metal Ions
Authors: Liu Xia , Yang Xiaoping , Ma Yanan , Liu Jieni , Shi Dongliang , Niu Mengyu 
Published: July 2020

Summary of main observation and conclusionOne six‐metal Zn(II)‐Yb(III) complex [Zn2Yb4L2(OAc)10(OH)2(CH3OH)2] (1) was constructed from Schiff base ligand bis(3‐methoxysalicylidene)ethylene‐1,2‐phenylenediamine (H2L). 1 shows a nanoscale rectangular structure with dimensions of approximately 0.8 nm × 1.1 nm × 2.8 nm. Excited by ligand‐centered absorption bands, 1 shows typical near‐infrared emission of Yb3+ ion. Interestingly, 1 exhibits lanthanide luminescent response towards metal ions, especially to Cd2+ at ppm level.
Comparing Onset of Biosimilar Versus Generic Competition in the United States
Authors: Beall Reed F. , Ronksley Paul E. , Wick James , Darrow Jonathan J. , Sarpatwari Ameet , Kesselheim Aaron S. 
Published: July 2020

We sought to compare expected and observed biosimilar and generic entry dates among new drugs approved by the US Food and Drug Administration (FDA) between 2000 and 2012. We defined expected biosimilar and generic entry dates as the later of the expiration of the key patent term or statutory exclusivity (12 years for biologics, 5 years for small molecule drugs not indicated for a rare disease, and 7 years for small molecule drugs indicated for a rare disease; plus 6 months if a pediatric extension had been granted). For drugs with expected entry prior to 2019, we calculated the proportion with observed biosimilar or generic entry. The expected biosimilar entry dates were estimated to be a median of 12.3 years (interquartile range (IQR) 12.0–14.0, n = 60) after FDA approval. The 12‐year biologic statutory exclusivity period comprised 98% of the median expected protection period. By contrast, expected generic entry was estimated to be a median of 12.2 years (IQR 8.4–14.0, n=268), or 7.2 years after the 5‐year small molecule statutory exclusivity (59% of the total expected market protection period). By 2019, observed biosimilar entry occurred in 12% of cases (3/25) and observed generic entry in 65% (101/155). We concluded that expected US market exclusivity periods are similar for biologic and small molecule drugs. Statutory exclusivity plays a more substantial role in market exclusivity protection for biologics. Biosimilar competition, currently lagging behind generic competition, will likely increase as the biosimilar market becomes established.
Unsymmetrical 2,4,6‐Triarylpyridines as Versatile Scaffolds for Deep‐Blue and Dual‐Emission Fluorophores
Authors: Fontes Luís F. B. , Nunes da Silva Raquel , Silva Artur M. S. , Guieu Samuel 
Published: July 2020

AbstractPyridines substituted with different aromatic groups at C‐2, C‐4 and C‐6 were prepared following a Kröhnke synthetic route. Introducing ortho‐anisole at C‐2 resulted in deep blue emitters in solution, with quantum yields up to 74 %. On the other hand, when ortho‐phenol was introduced, forming a strong hydrogen bond with the pyridine nitrogen, excited‐state intramolecular proton transfer was witnessed by the dual emission of the fluorophores, which is sensitive to the dye environment. The phenyl ring at C‐4 was used to introduce electron‐donating or withdrawing groups, to fine‐tune the photophysical properties of the dyes. Crystal structures of the fluorophores, together with theoretical studies using DFT/TD‐DFT calculations, were used to rationalize the experimental photophysical properties of the two families of dyes. Unsymmetrical 2,4,6‐triarylpyridines are therefore versatile scaffolds for the preparation of deep‐blue and dual emission fluorophores, and are promising building blocks for luminescent devices and sensors.