bluuebunny/crossref_metadata_2025_split huggingface dataset:
Asymmetric Total Synthesis of Oxazolomycins B and C
Authors: Song Yeonghun , Kim Jae Hyun , Kim Young Chan , Kim Sanghee 
Published: May 2021

AbstractEfforts towards the first total synthesis of (−)‐oxazolomycin B and (+)‐oxazolomycin C from the intermediate of our previous synthesis of (+)‐neoxazolomycin are reported. The syntheses were achieved in a longest linear sequence of 25 steps from the amino acid serine in 3.6 and 2.7 % overall yields, respectively. The efficiency of our approach is derived from silyl triflate‐mediated reductive oxazolidine ring‐opening and Fürstner's Ru‐catalyzed hydrosilylation and protodesilylation reactions. The obtained spectra and optical rotations were in good agreement with those of natural products, thus confirming the structures.
A Proton‐Responsive Pyridyl(benzamide)‐Functionalized NHC Ligand on Ir Complex for Alkylation of Ketones and Secondary Alcohols
Authors: Kaur Mandeep , U Din Reshi Noor , Patra Kamaless , Bhattacherya Arindom , Kunnikuruvan Sooraj , Bera Jitendra K. 
Published: May 2021

AbstractA Cp*Ir(III) complex (1) of a newly designed ligand L1 featuring a proton‐responsive pyridyl(benzamide) appended on N‐heterocyclic carbene (NHC) has been synthesized. The molecular structure of 1 reveals a dearomatized form of the ligand. The protonation of 1 with HBF4 in tetrahydrofuran gives the corresponding aromatized complex [Cp*Ir(L1H)Cl]BF4 (2). Both compounds are characterized spectroscopically and by X‐ray crystallography. The protonation of 1 with acid is examined by 1H NMR and UV‐vis spectra. The proton‐responsive character of 1 is exploited for catalyzing α‐alkylation of ketones and β‐alkylation of secondary alcohols using primary alcohols as alkylating agents through hydrogen‐borrowing methodology. Compound 1 is an effective catalyst for these reactions and exhibits a superior activity in comparison to a structurally similar iridium complex [Cp*Ir(L2)Cl]PF6 (3) lacking a proton‐responsive pendant amide moiety. The catalytic alkylation is characterized by a wide substrate scope, low catalyst and base loadings, and a short reaction time. The catalytic efficacy of 1 is also demonstrated for the syntheses of quinoline and lactone derivatives via acceptorless dehydrogenation, and selective alkylation of two steroids, pregnenolone and testosterone. Detailed mechanistic investigations and DFT calculations substantiate the role of the proton‐responsive ligand in the hydrogen‐borrowing process.
Preparation of Butadienylpyridines by Iridium‐NHC‐Catalyzed Alkyne Hydroalkenylation and Quinolizine Rearrangement
Authors: Azpíroz Ramón , Greger Ingo , Oro Luis A. , Passarelli Vincenzo , Castarlenas Ricardo , Pérez‐Torrente Jesús J. 
Published: May 2021

AbstractIridium(I) N‐heterocyclic carbene complexes of formula Ir(κ2O,O’‐BHetA)(IPr)(η2‐coe) [BHetA=bis‐heteroatomic acidato, acetylacetonate or acetate; IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐carbene; coe=cyclooctene] have been prepared by treating Ir(κ2O,O’‐BHetA)(η2‐coe)2 complexes with IPr. These complexes react with 2‐vinylpyridine to afford the hydrido‐iridium(III)‐alkenyl cyclometalated derivatives IrH(κ2O,O’‐BHetA)(κ2N,C‐C7H6N)(IPr) through the iridium(I) intermediate Ir(κ2O,O’‐BHetA)(IPr)(η2‐C7H7N). The cyclometalated IrH(κ2O,O’‐acac)(κ2N,C–C7H6N)(IPr) complex efficiently catalyzes the hydroalkenylation of aromatic and aliphatic terminal alkynes and enynes with 2‐vinylpyridine to afford 2‐(4R‐butadienyl)pyridines with Z,E configuration as the major reaction products (yield up to 89 %). In addition, unprecedented (Z)‐2‐butadienyl‐5R‐pyridine derivatives have been obtained as minor reaction products (yield up to 21 %) from the elusive 1Z,3gem‐butadienyl hydroalkenylation products. These compounds undergo a thermal 6π‐electrocyclization to afford bicyclic 4H‐quinolizine derivatives that, under catalytic reaction conditions, tautomerize to 6H‐quinolizine to afford the (Z)‐2‐(butadienyl)‐5R‐pyridine by a retro‐electrocyclization reaction.
Hyperpolarized 13C Magnetic Resonance Imaging of Fumarate Metabolism by Parahydrogen‐induced Polarization: A Proof‐of‐Concept in vivo Study
Authors: Stewart Neil J. , Nakano Hitomi , Sugai Shuto , Tomohiro Mitsushi , Kase Yuki , Uchio Yoshiki , Yamaguchi Toru , Matsuo Yujirou , Naganuma Tatsuya , Takeda Norihiko , Nishimura Ikuya , Hirata Hiroshi , Hashimoto Takuya , Matsumoto Shingo 
Published: May 2021

AbstractThe front cover artwork is provided by the group of Dr. Neil J. Stewart, Prof. Hiroshi Hirata, and Dr. Shingo Matsumoto (Hokkaido University, Japan) as well as Dr. Takuya Hashimoto (Chiba University, Japan). The image shows hyperpolarized 13C fumarate metabolism to hyperpolarized 13C malate, which is released into the extracellular space in regions of necrotic cell death, where the cell membrane is disrupted. Read the full text of the Article at 10.1002/cphc.202001038.
Assessing Protein Synthesis and Degradation Rates in Arabidopsis thaliana Using Amino Acid Analysis
Authors: Ishihara Hirofumi , Moraes Thiago A. , Arrivault Stéphanie , Stitt Mark 
Published: May 2021

AbstractPlants continually synthesize and degrade proteins, for example, to adjust protein content during development or during adaptation to new environments. In order to estimate global protein synthesis and degradation rates in plants, we developed a relatively simple and inexpensive method using a combination of 13CO2 labeling and mass spectrometry–based analyses. Arabidopsis thaliana plants are subjected to a 24‐hr 13CO2 pulse followed by a 4‐day 12CO2 chase. Soluble alanine and serine from total protein and glucose from cell wall material are analyzed by gas chromatography time‐of‐flight mass spectrometry (GC‐TOF‐MS) and their 13C enrichment (%) is estimated. The rate of protein synthesis during the 13CO2 pulse experiment is defined as the rate of incorporation of labeled amino acids into proteins normalized by a correction factor for incomplete enrichment in free amino acid pools. The rate of protein degradation is estimated as the difference between the rate of protein synthesis and the relative growth rate calculated using the 13C enrichment of glucose from cell wall material. Degradation rates are also estimated from the 12CO2 pulse experiment. The following method description includes setting up and performing labeling experiments, preparation and measurement of samples, and calculation steps. In addition, an R script is provided for the calculations. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC.Basic Protocol 1: Setting up the 13CO2 labeling system and stable isotope labeling of Arabidopsis thaliana rosette leavesBasic Protocol 2: Extraction of soluble amino acids for GC‐TOF‐MS analysisBasic Protocol 3: Preparation of amino acids from total protein for GC‐TOF‐MS analysisBasic Protocol 4: Preparation of sugars from cell wall material for GC‐TOF‐MS analysisBasis Protocol 5: GC‐TOF‐MS analysis of 13C‐labeled samples and estimation of 13C enrichment (%)Basis Protocol 6: Estimation of protein synthesis and degradation rates
Agrobacterium‐Mediated Transformation of Setaria viridis, a Model System for Cereals and Bioenergy Crops
Authors: Finley Todd , Chappell Hal , Veena Veena 
Published: May 2021

AbstractSetaria viridis is an emerging model system for the genetic and molecular characterization of cereals and bioenergy crops. Here, we describe a detailed procedure for genetic transformation of the S. viridis accession line ME034V‐1. This method utilizes callus generated from mature seeds for infection with Agrobacterium tumefaciens strain AGL1 to regenerate hygromycin‐resistant stable transgenic plants. It takes approximately 7 weeks to generate callus from mature seeds, 11‐17 weeks from infection to the regeneration of transgenic lines, and an additional 3‐4 weeks for plant growth in the greenhouse for seed collection. The protocol as presented consistently results in transformation frequency of approximately 25% for the generation of transgenic plants, with fewer escapes and higher survivability in soil for optimal seed collection. © 2021 Donald Danforth Plant Science Center. Current Protocols published by Wiley Periodicals LLC.Basic Protocol 1: Generation of S. viridis (Accession ME034V‐1) callus from mature seedsBasic Protocol 2: Agrobacterium‐mediated transformation of callus to generate transgenic plantsBasic Protocol 3: Plantlet transplantation in soil, plant growth in greenhouse, and seed collectionSupport Protocol: Preparation of Agrobacterium culture for infection
SHIRPA as a Neurological Screening Battery in Mice
Authors: Lalonde Robert , Filali Mohammed , Strazielle Catherine 
Published: May 2021

AbstractThe SmithKline, Harwell, Imperial College, Royal Hospital, Phenotype Assessment (SHIRPA) is a rapid battery of tests comprising 42 measurements of motor activity, coordination, postural control, muscle tone, autonomic functions, and emotional reactivity, as well as reflexes dependent on visual, auditory, and tactile modalities. Individual scores in SHIRPA are sensitive in detecting phenotypes of several experimental models of neural disease, especially cerebellar degeneration and Alzheimer disease, and combined subscores have been useful in estimating the impact of vascular anomalies and exposure to infectious agents. In cerebellar degeneration, weak forelimb grip, impaired wire maneuver and air righting, and negative geotaxis appear as prevalent features. Most of the measures in the battery are susceptible to change after gene modifications or physiological alterations. SHIRPA can be used both in adult mice and mice in the preweaning period to screen for sensorimotor function and emotional reactivity, not selective attention or memory. © 2021 Wiley Periodicals LLCThis article was corrected on 28 July 2022. See the end of the full text for details.Basic Protocol: Step‐by‐step procedure for SHIRPA
Waste to Wealth: Chemical Recycling and Chemical Upcycling of Waste Plastics for a Great Future
Authors: Chen Huan , Wan Kun , Zhang Yayun , Wang Yanqin 
Published: May 2021

AbstractThe linear approach to resource utilization has led to the accumulation of waste plastic in the environment for decades. Unfortunately, both traditional mechanical recycling and incineration have faced their bottlenecks that have always resulted in quality deterioration and value recovery failures. Recently, chemical recycling and upcycling processes, including the conversion of plastics into their virgin monomers, liquid fuels, or chemical feedstocks to produce value‐added products, have been identified as the most promising strategy for recovering value from waste plastics. However, these methods are often cost prohibitive and relying on stringent conditions compared to current recycling methods. Accordingly, this Minireview summarizes recent trends and achievements in the chemical recycling and upcycling of waste plastics. We highlight three research topics: depolymerization of plastics into monomers; degradation of plastics into liquid fuels and waxes; and conversion of plastics into hydrogen, fine chemical feedstocks, and value‐added functional materials. Indeed, chemical recycling and upcycling is a bright path to a circular and environmentally friendly plastic economy.
Automatisierter Bau von Kalksandstein‐Mauerwerk mit Seilrobotern
Authors: Roske Thomas , Lipowsky Justus , Palzer Ulrich , Eden Wolfgang , Schäfers Martin , Lemmen Patrik , Heidel Robin , Boumann Roland , Spengler Arnim , Bruckmann Tobias 
Published: May 2021

AbstractSeilroboter stellen einen innovativen und vielversprechenden Ansatz bei der Digitalisierung und Automatisierung im Mauerwerksbau dar. Zudem verfügen sie über das Potenzial, die Verarbeitung von Mauersteinen zu revolutionieren. Denn der Einsatz von Seilrobotern eröffnet die Möglichkeit, große Bauvolumina auch bei komplexen Geometrien und reduziertem Personaleinsatz in kürzester Zeit zu errichten. Damit steigt perspektivisch nicht nur die Produktivität in den Bauunternehmen, es wird auch dem Mangel an qualifizierten Fachkräften entgegengewirkt und das Image der Branche insgesamt verbessert.An der praktischen Umsetzung der Digitalisierung und Automatisierung im Mauerwerksbau mittels Seilroboter arbeitet seit dem 1. Februar 2019 die Forschungsvereinigung Kalk‐Sand e.V. gemeinsam mit dem Lehrstuhl für Mechatronik und dem Institut für Baubetrieb und Baumanagement der Universität Duisburg‐Essen sowie dem IAB – Institut für Angewandte Bauforschung Weimar gGmbH.Der vorliegende Beitrag gibt einen Einblick in die Realisierung eines Funktionsmusters eines Seilroboters inklusive einer Bemörtelungseinrichtung, mit dem das automatisierte Mauern anhand eines eingeschossigen Mustergebäudes demonstriert werden soll.
Cascading effects: insights from the U.S. Long Term Ecological Research Network
Authors: Bahlai Christie A. , Hart Clarisse , Kavanaugh Maria T. , White Jeffrey D. , Ruess Roger W. , Brinkman Todd J. , Ducklow Hugh W. , Foster David R. , Fraser William R. , Genet Hélène , Groffman Peter M. , Hamilton Stephen K. , Johnstone Jill F. , Kielland Knut , Landis Douglas A. , Mack Michelle C. , Sarnelle Orlando , Thompson Jonathan R. 
Published: May 2021

AbstractEcosystems across the United States are changing in complex and unpredictable ways and analysis of these changes requires coordinated, long‐term research. This paper is a product of a synthesis effort of the U.S. National Science Foundation funded Long‐Term Ecological Research (LTER) network addressing the LTER core research area of “populations and communities.” This analysis revealed that each LTER site had at least one compelling “story” about what their site would look like in 50–100 yr. As the stories were prepared, themes emerged, and the stories were group into papers along five themes: state change, connectivity, resilience, time lags, and cascading effects. This paper addresses the cascading effects theme and includes stories from the Bonanza Creek (boreal), Kellogg Biological Station (agricultural and freshwater), Palmer (Antarctica), and Harvard Forest (temperate forest) LTER sites. We define cascading effects very broadly to include a wide array of unforeseen chains of events that result from a variety of actions or changes in a system. While climate change is having important direct effects on boreal forests, indirect effects mediated by fire activity—severity, size, and return interval—have large cascading effects over the long term. In northeastern temperate forests, legacies of human management and disturbance affect the composition of current forests, which creates a cascade of effects that interact with the climate‐facilitated invasion of an exotic pest. In Antarctica, declining sea ice creates a cascade of effects including declines in Adèlie and increases in Gentoo penguins, changes in phytoplankton, and consequent changes in zooplankton populations. An invasion of an exotic species of lady beetle is likely to have important future effects on pest control and conservation of native species in agricultural landscapes. New studies of zebra mussels, a well‐studied invader, have established links between climate, the heat tolerance of the mussels, and harmful algal blooms. Collectively, these stories highlight the need for long‐term studies to sort out the complexities of different types of ecological cascades. The diversity of sites within the LTER network facilitates the emergence of overarching concepts about trophic interactions as an important driver of ecosystem structure, function, services, and futures.
An Acyclic Diaminocarbene Complex of Platinum Formed by Desulfurization of 1,3‐Bis(3‐methylpyridin‐2‐yl)thiourea
Authors: Bulak Ece , Dogan Ilknur , Varnali Tereza , Schwederski Brigitte , Gunal Sule Erol , Lönnecke Peter , Bubrin Martina , Kaim Wolfgang 
Published: May 2021

AbstractThe reaction of the ambidentate ligand 1,3‐bis(3‐methylpyridin‐2‐yl)thiourea (1) with [PtCl2(dmso)2] in dichloromethane led to formation of a poorly soluble compound 2, characterized as a conventional chelate complex [PtCl2(1)]=2. Reaction in methanol resulted in desulfurization to produce a fluorescing cationic diaminocarbene−platinum(II) complex 3, the structure of which was elucidated by X‐ray crystallography, mass spectrometry and NMR. Experimental findings were supported by DFT calculations.
Free Fatty Acids Reduction in Waste Cooking Oil by Rhodosporidium toruloides and Simultaneous Carotenoids, Lipids, and PAL Enzyme Production in a Two‐Phase Culture System
Authors: Lee Jaslyn Jie Lin , Li Aaron , Lyu Xiaomei , Kim Jae Jung , Chen Wei Ning 
Published: May 2021

AbstractWaste cooking oil (WCO) is a problematic waste product that contains free fatty acids (FFAs), preventing it from being valorized easily as biodiesel and poses an environmental hazard if incorrectly disposed. The use of WCO as a carbon source for Rhodosporidium toruloides (R. toruloides) using a two‐phase culture system is developed. The normal growth of R. toruloides when cultured in WCO (OD600 52) reveals its ability to use a hydrophobic substrate as the carbon source compared to glucose (OD600 51.9). Interestingly, the extracellular lipase activity when R. toruloides is grown on WCO is 14.4 U mL−1 compared to when grown on glucose (2.4 U mL−1). Additionally, FFA levels in WCO are reduced from 2% to 0.2% at end of fermentation, suggesting that R. toruloides can consume FFA. Furthermore, higher yield of beneficial products: β‐carotene (4.57 µg mL−1), torularhodin (4.2 µg mL−1), fatty acids (1 mg mL−1), and phenylalanine ammonia‐lyase (PAL) enzyme (0.12 µmol mg−1) are produced when WCO is the carbon source, compared to glucose (4.1 µg mL−1 β‐carotene, 3.0 µg mL−1 torularhodin, 1 mg mL−1 of fatty acids, and 0.096 µmol mg−1 PAL enzyme). This is a first study that shows R. toruloides can grow on hydrophobic carbon source.
Antioxidant and Biological Activities of Novel Structured Monoacylglycerol Derivatives with Phenolic Acids
Authors: Gandhi Bhukya , Juliya Johny , Dileep Veeragoni , Uma Rajeswari Batchu , Misra Sunil , Kaki Shiva Shanker 
Published: May 2021

AbstractNovel structured monoacylglycerol (MAG)‐based phenolic lipids are synthesized from11‐bromoundecanoic acid, phenolic acids, and solketal. Selected phenolic acids namely 4‐hydroxy benzoic, vanillic, syringic, cinnamic, p‐coumaric, sinapic, 4‐fluorocinnamic, 4‐hydroxyphenyl acetic acid, 3‐(4‐hydroxyphenyl) propanoic and dihydrocaffeic acids are employed for the synthesis of ten novel MAG‐based phenolic lipids. The synthesized phenolic lipids are characterized by FT‐IR, NMR, and mass spectra analysis. All the compounds are evaluated for antioxidant, antimicrobial, and cytotoxic activities. MAG derivative 8g of sinapic acid exhibits excellent antioxidant activity in both DPPH assay and inhibition of lipid oxidation assay. MAG derivative 8f bearing p‐coumaric acid shows good antimicrobial activity against both Gram‐positive and Gram‐negative bacterial strains with a minimum inhibitory concentration (MIC) value of 6.25 µm mL−1. All the synthesized compounds are found to exhibit cytotoxicity against B16, DU145, and CHO cell lines, while sinapic and p‐coumaric acid derivatives exhibit better activities compared to other derivatives.
Propargyl Radicals in Organic Synthesis
Authors: Muresan Marcus , Subramanian Hariharaputhiran , Sibi Mukund P. , Green James R. 
Published: May 2021

AbstractThe appearance of propargyl radicals as synthetic intermediates has increased in recent years from a structural curiosity to a frequent occurrence. This minireview covers the synthetically relevant organic chemistry involving the intermediacy of propargyl radicals. The review is organized by the process employed in radical generation, including H‐atom abstraction, propargyl‐X homolyses, radical addition to enynes, reduction of polar C=X bonds, reductions of stable carbocations, and metal‐mediated coupling reactions. The relevant mechanisms of generation and reaction are discussed, as are applications in syntheses of target molecules of interest.
Dietary supplementation with N‐3 polyunsaturated fatty acid‐enriched fish oil promotes wound healing after ultraviolet B‐induced sunburn in mice
Authors: Meng Fanxing , Qiu Jiayi , Chen Houjie , Shi Xiaojun , Yin Meifang , Zhu Meishu , Yang Guang 
Published: May 2021

AbstractN‐3 polyunsaturated fatty acids (n‐3 PUFA) can alleviate ultraviolet B (UVB)‐induced skin cancers, but their effects on sunburn and upcoming wound healing remain controversial. This study aimed to explore the impact of n‐3 PUFA‐enriched fish oil (n‐3 PUFA‐FO) on UVB‐induced sunburns and subsequent healing. Sixty C57BL/6 female mice were divided into two groups. The treated group mice were fed n‐3 PUFA‐FO for the entire duration of the experiment. Mice in the control group were fed a standard diet. After two weeks of n‐3 PUFA‐FO feeding, mice were exposed to UVB for 20 min and sacrificed 20 d later. Skin photodamage and lesion area were recorded during wound healing. Epidermal lesion thickness was quantified in hematoxylin and eosin‐stained skin sections. Inflammation and macrophage polarization were assessed by qRT‐PCR. Oxidative stress and antioxidant enzyme activity were quantified using specific ELISA kits. N‐3 PUFA‐FO feeding decreased UVB photodamage and accelerated wound healing progression, both of which were coupled with less intense inflammation and increased macrophage M2 phenotype polarization. Furthermore, n‐3 PUFA‐FO brought about a decrease in malondialdehyde (MDA) levels but increased the activity of catalase (CAT) and glutathione peroxidase (GP), without changing superoxide dismutase (SOD) activity. N‐3 PUFA‐FO protects against UVB‐induced skin photodamage and promotes wound healing by modulating macrophage phenotypic polarization and antioxidant enzyme activities. N‐3 PUFA‐FO could be a novel therapeutic approach for both the prevention and treatment of sunburns.
Penalized linear mixed models for structured genetic data
Authors: Reisetter Anna C. , Breheny Patrick 
Published: May 2021

AbstractMany genetic studies that aim to identify genetic variants associated with complex phenotypes are subject to unobserved confounding factors arising from environmental heterogeneity. This poses a challenge to detecting associations of interest and is known to induce spurious associations when left unaccounted for. Penalized linear mixed models (LMMs) are an attractive method to correct for unobserved confounding. These methods correct for varying levels of relatedness and population structure by modeling it as a random effect with a covariance structure estimated from observed genetic data. Despite an extensive literature on penalized regression and LMMs separately, the two are rarely discussed together. The aim of this review is to do so while examining the statistical properties of penalized LMMs in the genetic association setting. Specifically, the ability of penalized LMMs to accurately estimate genetic effects in the presence of environmental confounding has not been well studied. To clarify the important yet subtle distinction between population structure and environmental heterogeneity, we present a detailed review of relevant concepts and methods. In addition, we evaluate the performance of penalized LMMs and competing methods in terms of estimation and selection accuracy in the presence of a number of confounding structures.
Genetic, epigenetic, and post‐transcriptional basis of divergent tissue regenerative capacities among vertebrates
Authors: Khyeam Sheamin , Lee Sukjun , Huang Guo N. 
Published: May 2021

AbstractRegeneration is widespread across the animal kingdom but varies vastly across phylogeny and even ontogeny. Adult mammalian regeneration in most organs and appendages is limited, while vertebrates such as zebrafish and salamanders are able to regenerate various organs and body parts. Here, we focus on the regeneration of appendages, spinal cord, and heart—organs and body parts that are highly regenerative among fish and amphibian species but limited in adult mammals. We then describe potential genetic, epigenetic, and post‐transcriptional similarities among these different forms of regeneration across vertebrates and discuss several theories for diminished regenerative capacity throughout evolution.