bluuebunny/crossref_metadata_2025_split huggingface dataset:
N‐Heterocyclic Carbene Organocatalysis: With or Without Carbenes?
Authors: Gehrke Sascha , Hollóczki Oldamur 
Published: July 2020

AbstractIn this work the mechanism of the aldehyde umpolung reactions, catalyzed by azolium cations in the presence of bases, was studied through computational methods. Next to the mechanism established by Breslow in the 1950s that takes effect through the formation of a free carbene, we have suggested that these processes can follow a concerted asynchronous path, in which the azolium cation directly reacts with the substrate, avoiding the formation of the carbene intermediate. We hereby show that substituting the azolium cation, and varying the base or the substrate do not affect the preference for the concerted reaction mechanism. The concerted path was found to exhibit low barriers also for the reactions of thiamine with model substrates, showing that this path might have biological relevance. The dominance of the concerted mechanism can be explained through the specific structure of the key transition state, avoiding the liberation of the highly reactive, and thus unstable carbene lone pair, whereas activating the substrate through hydrogen‐bonding interactions. Polar and hydrogen‐bonding solvents, as well as the presence of the counterions of the azolium salts facilitate the reaction through carbenes, bringing the barriers of the two reaction mechanisms closer, in many cases making the concerted path less favorable. Thus, our data show that by choosing the exact components in a reaction, the mechanism can be switched to occur with or without carbenes.
Light‐Promoted Organocatalysis with N‐Heterocyclic Carbenes
Authors: Mavroskoufis Andreas , Jakob Michael , Hopkinson Matthew N. 
Published: July 2020

AbstractThe combination of N‐heterocyclic carbene (NHC)‐organocatalysis with photochemical activation can lead to unprecedented reaction pathways not observed without light. A selection of dual catalytic systems merging NHCs with photoredox catalysis, for example, have leveraged the ability of NHCs to stabilize intermediate radical species and facilitate single electron transfer events. Furthermore, NHCs can transiently modulate the photochemical properties of a substrate and enable direct absorption of otherwise photoinactive organic compounds. In this Concept article, the recent advances in this rapidly developing field are summarized. For each transformation, a particular focus is placed on the mechanistic aspects of the process while key features that highlight the synthetic potential of the light mediated NHC organocatalysis are presented.
Can We Increase Economic Return from Sugarbeet with Slow‐Release Nitrogen Additions?
Authors: Chatterjee A. 
Published: July 2020

AbstractFertilizer N management is critical for sugarbeet production. A field experiment was conducted to compare Environmentally Smart Nitrogen (ESN) with urea applied at 90, 120, and 150 lb N/ac for sugarbeet production in the Red River Valley of Minnesota during the 2017–2018 growing seasons. Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/743.
Rethinking trophic niches: Speed and body mass colimit prey space of mammalian predators
Authors: Hirt Myriam R. , Tucker Marlee , Müller Thomas , Rosenbaum Benjamin , Brose Ulrich 
Published: June 2020

Abstract

Realized trophic niches of predators are often characterized along a one‐dimensional range in predator–prey body mass ratios. This prey range is constrained by an “energy limit” and a “subdue limit” toward small and large prey, respectively. Besides these body mass ratios, maximum speed is an additional key component in most predator–prey interactions.

Here, we extend the concept of a one‐dimensional prey range to a two‐dimensional prey space by incorporating a hump‐shaped speed‐body mass relation. This new “speed limit” additionally constrains trophic niches of predators toward fast prey.

To test this concept of two‐dimensional prey spaces for different hunting strategies (pursuit, group, and ambush predation), we synthesized data on 63 terrestrial mammalian predator–prey interactions, their body masses, and maximum speeds.

We found that pursuit predators hunt smaller and slower prey, whereas group hunters focus on larger but mostly slower prey and ambushers are more flexible. Group hunters and ambushers have evolved different strategies to occupy a similar trophic niche that avoids competition with pursuit predators. Moreover, our concept suggests energetic optima of these hunting strategies along a body mass axis and thereby provides mechanistic explanations for why there are no small group hunters (referred to as “micro‐lions”) or mega‐carnivores (referred to as “mega‐cheetahs”).

Our results demonstrate that advancing the concept of prey ranges to prey spaces by adding the new dimension of speed will foster a new and mechanistic understanding of predator trophic niches and improve our predictions of predator–prey interactions, food web structure, and ecosystem functions.
Optimizing the widely used nuclear protein‐coding gene primers in beetle phylogenies and their application in the genus Sasajiscymnus Vandenberg (Coleoptera: Coccinellidae)
Authors: Huang Weidong , Xie Xiufeng , Peng Feng , Liang Xinyue , Wang Xingmin , Chen Xiaosheng 
Published: June 2020

AbstractAdvances in genomic biology and the increasing availability of genomic resources allow developing hundreds of nuclear protein‐coding (NPC) markers, which can be used in phylogenetic research. However, for low taxonomic levels, it may be more practical to select a handful of suitable molecular loci for phylogenetic inference. Unfortunately, the presence of degenerate primers of NPC markers can be a major impediment, as the amplification success rate is low and they tend to amplify nontargeted regions. In this study, we optimized five NPC fragments widely used in beetle phylogenetics (i.e., two parts of carbamoyl‐phosphate synthetase: CADXM and CADMC, Topoisomerase, Wingless and Pepck) by reducing the degenerate site of primers and the length of target genes slightly. These five NPC fragments and 6 other molecular loci were amplified to test the monophyly of the coccinellid genus Sasajiscymnus Vandenberg. The analysis of our molecular data set clearly supported the genus Sasajiscymnus may be monophyletic but confirmation with an extended sampling is required. A fossil‐calibrated chronogram was generated by BEAST, indicating an origin of the genus at the end of the Cretaceous (77.87 Myr). Furthermore, a phylogenetic informativeness profile was generated to compare the phylogenetic properties of each gene more explicitly. The results showed that COI provides the strongest phylogenetic signal among all the genes, but Pepck, Topoisomerase, CADXM and CADMC are also relatively informative. Our results provide insight into the evolution of the genus Sasajiscymnus, and also enrich the molecular data resources for further study.
In‐site investigation of regional outburst prevention in coal roadway strip of a deep mine using an improved method
Authors: Yang Huiming , Wang Zhonghua , Zhang Yongjiang , Cao Jianjun , Liu Yanbao , Yang Xuelin , Li Chengcheng 
Published: July 2020

AbstractWith the increase of mining depth, the occurrence mechanism of coal and gas outburst becomes more complex, and stress‐dominated outburst disaster has become one of the major safety problems in deep coal mines. Therefore, stress relief of coal seam has become an urgent technical demand for outburst prevention method in deep mines. In this study, based on zonal disintegration characteristics of deep surrounding rock, a regional strip outburst prevention method, called strip stress relief combined with gas extraction through stress‐relief floor roadway, was proposed, and relevant in‐site investigations were carried out in the Qujiang coal mine in China. Our results show that the zonal disintegration phenomenon occurs in the high‐stress surrounding rock at great depths, and induces the stress‐relief effect on the upper coal seam, in which the permeability and extraction radius of boreholes are increased greatly. The results of deformation and failure of surrounding rock of floor roadway show that from the surface to deep regions, fractured and nonfractured zones were alternatively distributed in the surrounding rock of deep floor roadways, the damage degree of surrounding rock was gradually weakened, and the width of fractured area was gradually reduced. The displacement of surrounding rock also presented the characteristics of alternative distribution of wave peak and trough. Moreover, the deformation and failure of surrounding rock presented a time‐dependent rheological behavior. In the stress‐relief zone, the coal seam permeability was enhanced significantly, with the maximum value being 43 times larger than that of the original coal seam. The effective gas extraction radius of the borehole was improved by 15%‐45%. During the driving period of coal roadways, the outburst risk prediction indexes K1 and S of the working face were lower than the critical value, and the driving speed of the coal roadway improved from 40 m per month to 100 m per month. This indicates that the proposed strip regional outburst prevention method can simultaneously reduce the ground stress and the gas content, and can effectively eliminate the outburst risk of coal roadway in deep mines.
Transcriptomic analysis of photosynthesis‐related genes regulated by alternate wetting and drying irrigation in flag leaves of rice
Authors: Song Tao , Yang Feng , Das Debatosh , Chen Moxian , Hu Qijuan , Tian Yuan , Cheng Chaolin , Liu Yue , Zhang Jianhua 
Published: July 2020

AbstractAlternate wetting and drying (AWD) irrigation has been widely used to replace continuous flooding (CF), which does not result in yield loss while improving water productivity. However, it is still unexplored as to how this agricultural practice would affect gene expression to control plant physiology. In this study, we found that photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), chlorophyll (Chl) content, and leaf water potential (Lwp) significantly decreased while abscisic acid (ABA) content and water use efficiency (WUE) increased when soil water potential reached to −15 kPa in the AWD irrigation regime. We then analyzed the differences between AWD and CF irrigation practices in transcriptomic profiles for flag leaves. Genes were found to be differentially expressed in photosynthesis related pathways namely, Chl biosynthesis, photosynthesis‐antenna proteins pathway, photosynthesis process, and ABA signal transduction pathway. The study provides important information on the morphological adaptations observed in the flag leaves in response to AWD irrigation, which will act as a basic framework to conduct molecular studies for improving rice cultivation.
Case of post‐orgasmic illness syndrome associated with hypogonadism
Authors: Takeshima Teppei , Kuroda Shinnosuke , Yumura Yasushi 
Published: July 2020

IntroductionPost‐orgasmic illness syndrome is a rare condition that occurs after ejaculation and persists for 2–7 days and is characterized by flu‐like symptoms, which can significantly reduce quality of life.Case presentationA 21‐year‐old unmarried man was referred to our hospital due to flu‐like symptoms that developed after ejaculation by masturbation and persisted for about 2 days. The patient’s free testosterone level was slightly lower than normal. Nonsteroidal anti‐inflammatory drugs were initially administered and helped relieve headache and muscle pain. Thereafter, the patient was able to ejaculate three times a week. In addition, after administering testosterone enanthate once or twice a month, his general fatigue significantly improved, and he could ejaculate every day.ConclusionThe pathophysiology of post‐orgasmic illness syndrome has not been fully elucidated. The treatments for this condition must be accurately selected according to pathophysiology.
Histone demethylase JHDM2A regulates H3K9 dimethylation in response to arsenic‐induced DNA damage and repair in normal human liver cells
Authors: Zhang An‐liu , Tang Shun‐fang , Yang Yue , Li Chang‐zhe , Ding Xue‐jiao , Zhao Hua , Wang Jun‐hua , Yang Guang‐hong , Li Jun 
Published: July 2020

AbstractLong‐term arsenic exposure is a worldwide public health problem that causes serious harm to human health. The liver is the main target organ of arsenic toxicity; arsenic induces disruption of the DNA damage repair pathway, but its mechanisms remain unclear. In recent years, studies have found that epigenetic mechanisms play an important role in arsenic‐induced lesions. In this study, we conducted experiments in vitro using normal human liver cells (L‐02) to explore the mechanism by which the histone demethylase JHDM2A regulates H3K9 dimethylation (me2) in response to arsenic‐induced DNA damage. Our results indicated that arsenic exposure upregulated the expression of JHDM2A, downregulated global H3K9me2 modification levels, increased the H3K9me2 levels at the promoters of base excision repair (BER) genes (N‐methylpurine‐DNA glycosylase [MPG], XRCC1 and poly(ADP‐ribose)polymerase 1) and inhibited their expression levels, causing DNA damage in cells. In addition, we studied the effects of overexpression and inhibition of JHDM2A and found that JHDM2A can participate in the molecular mechanism of arsenic‐induced DNA damage via the BER pathway, which may not be involved in the BER process because H3K9me2 levels at the promoter region of the BER genes were unchanged following JHDM2A interference. These results suggest a potential mechanism by which JHDM2A can regulate the MPG and XRCC1 genes in the process of responding to DNA damage induced by arsenic exposure and can participate in the process of DNA damage repair, which provides a scientific basis for understanding the epigenetic mechanisms and treatments for endemic arsenic poisoning.
CircHN1 affects cell proliferation and migration in gastric cancer
Authors: Zhang Yu , Wang Maoye , Zang Xueyan , Mao Zheying , Chen Yanke , Mao Fei , Qian Hui , Xu Wenrong , Zhang Xu 
Published: July 2020

AbstractBackgroundIncreasing evidence indicates that circular RNAs (circRNAs) are dysregulated in human cancers. The biological roles of circRNAs in gastric cancer (GC) have not been well‐characterized.MethodsThe GEO database was used to analyze circRNA expression profile in GC. The expression level of target circRNA in tumor tissues and adjacent non‐tumor tissues was detected by reverse transcription‐quantitative PCR. Gene transfection was used to manipulate the expression of circRNAs. The biological roles of circRNAs in cell proliferation, migration, and invasion were determined by cell counting, colony formation, transwell migration, Matrigel invasion, and mouse xenograft tumor assays. The interactions between circRNAs and miRNAs were verified by RNA immunoprecipitation and luciferase reporter assays.ResultsWe found that circHN1 was upregulated in GC tissues and cell lines compared to adjacent non‐tumor tissues and normal gastric epithelial cells. Additionally, circHN1 silencing significantly promoted GC cell growth, colony formation, migration, and invasion, whereas circHN1 overexpression had the opposite effects. CircHN1 overexpression also suppressed gastric cancer growth in the mouse xenograft tumor model. CircHN1 was mainly localized in the cytoplasm of GC cells and could bind to AGO2. MiR‐1248 and miR‐375 were predicted to interact with circHN1 by bioinformatic analyses. MiR‐1248 and miR‐375 overexpression inhibited the activity of the circHN1 luciferase reporter.ConclusionCircHN1 is aberrantly expressed in GC and affects the proliferation and migration of gastric cancer cells by acting as miRNA sponge.
Accurate assessment of nonalcoholic fatty liver disease lesions in liver allograft biopsies by a smartphone platform: A proof of concept
Authors: Cesaretti Manuela , Gal Jocelyn , Bouveyron Charles , Diaspro Alberto , Fontas Eric , Antonini Andrea , Anty Rodolphe , Iannelli Antonio , Patouraux Stephanie 
Published: July 2020

AbstractMacrovesicular steatosis (MS) is a major risk factor for liver graft failure after transplantation and pathological microscopic examination of a frozen tissue section remains the gold standard for its assessment. However, the latter requires an experienced in‐house pathologist for correct and rapid diagnosis as well as specific equipment that is not always available. Smartphones, which are must‐have tools for everyone, are very suitable for incorporation into promising technology to generate moveable diagnostic tools as for telepathology. The study aims to compare the microscopic assessment of nonalcoholic fatty liver disease (NAFLD) spectrum in liver allograft biopsies by a smartphone microscopy platform (DIPLE device) to standard light microscopy. Forty‐two liver graft biopsies were evaluated in transmitted light, using an iPhone X and the microscopy platform. A significant correlation was reported between the two different approaches for graft MS assessment (Spearman's correlation coefficient: r = .93; p < .001) and for steatohepatitis feature (r = .56; p < .001; r = .45; p < .001). Based on these findings, a smartphone integrated with a cheap microscopy platform can achieve adequate accuracy in the assessment of NAFLD in liver graft and could be used as an alternative to standard light microscopy when the latter is unavailable.
ZnO/Fe3O4 nanoparticles promoted green synthesis of pyrazolo pyrimidinones: Study of antioxidant activity
Authors: Ghoorchibeigi Mona , Larijani Kambiz , Azar Parviz A. , Zare Karim , Mehregan Iraj 
Published: July 2020

AbstractThe preparation of pyrazolo pyrimidinone derivatives was performed by using five component reactions of phthalaldehyde, cyanomethylamine, electron deficient acetylenic compounds, isocyanate, hydrazine, and catalytic amounts of ZnO/Fe3O4‐magnetic nanoparticles as a high performance catalyst under ultrasonic conditions at ambient temperature in aquause media at room temperature. It should be mentioned that this catalyst was prepared using Spinacia oleracea water extract. In addition, for investigation of antioxidant ability, radical trapping by DPPH and reducing power of ferric ion experiments was performed. As a result, synthesized compounds show excellent radical trapping by DPPH and good reducing ability of ferric ion. The current procedure has the benefits for instance excellent yield of reaction, green media, and easy separation of product and catalyst.
Experimental assessment and implications of long‐term within‐trap mineralization of seston in lake trapping studies
Authors: Radbourne Alan D. , Ryves David B. 
Published: July 2020

AbstractSediment trapping is a widely accepted technique in lake studies for analyzing seasonal limnological events and can provide insight into ecological succession as well as the seasonal dynamics of organic and inorganic fluxes. More recently, organic flux measurement from traps has been especially important in estimating whole‐lake C sequestration as a basis for regional and global upscaling of C budgets across lake types. However, in‐trap mineralization or dissolution of components of collected sediment (seston) has not been systematically examined, and thus a reliable correction factor for in‐trap losses of various sedimentary fluxes (especially those involving organic carbon) is still unknown. This experimental study assesses the loss of algal biomass representative of a 6‐month carousel‐type (closed) sediment trap deployment in a deep, eutrophic lake under cold (~ 5°C) and anoxic ambient conditions typical of the hypolimnion in stratifying, temperate lakes. Results show a loss of organic matter (OM) at a consistent rate over 180 d, reducing the fraction of initial OM content by approximately a third after 180 d of deployment (linear regression of OM fraction loss = −0.001864t). The significance of these findings is demonstrated by application to published trap data; at Rostherne Mere, UK, which implies that annual OM fluxes are underestimated by 18.2% on average (range 13.7–23.2%). This highlights the far‐reaching implications for lake sediment trap methodology and our understanding of seston taphonomy, suggesting a mineralization correction factor for OM should be applied to traps deployed for longer than 1 week. With loss correction factored in, this study supports the reliability of longer‐term (i.e., ~ 6 months) sediment trap deployment.
A biomechanical finite element model to generate a library of cervix CTVs
Authors: Beekman Chris , van Beek Suzanne , Stam Jikke , Sonke Jan‐Jakob , Remeijer Peter 
Published: June 2020

PurposeTo generate a series of physiologically plausible cervix CTVs by biomechanically modeling organ deformation as a consequence of bladder filling. This series can serve as planning CTVs for radiotherapy treatment of cervical cancer patients using a library of plans (LoP) strategy.MethodsThe model was constructed based on the full and empty bladder scans of 20 cervical cancer patients, for which the bladder, rectum and the clinical target volume (CTV) of the cervix were delineated. Finite element modeling (FEM) was used to deform empty to full bladder anatomy. This deformation comprised two steps. In the first step, the surfaces of the bladder and rectum of the empty bladder anatomy were explicitly deformed to the full bladder anatomy and imported as enforced displacements into the biomechanical model. These surface displacements cause volumetric deformations of the bladder, rectum and cervix CTV meshes, dictated by their respective elastic properties and the type of contact among them. In the second step, the residual offset between the simulated and target CTV was corrected by an additional thin plate spline warp. Intermediate structural outputs of a linear superposition of the biomechanical and residual warp then constituted the library of CTVs for each patient. The residual warp was minimized by optimizing the FEM parameters over the 20 patients. Finally, the model was tested for nine healthy volunteers for which repeat MR scans were available as the bladder filled from empty to full. Small and large movers were identified depending on the extent of CTV motion, and analyzed separately. The proposed method was compared against the method currently used in our institute, in which intermediate structures are linearly interpolated between full and empty bladder anatomy, using a thin plate spline warp. The comparison metrics used were the ability to preserve CTV volume throughout the deformation, and residual offsets between repeat and library CTV.ResultsOptimal model parameters were found to be compatible with published values. While for the current method, the median CTV volume shrunk by 4% for large movers halfway the deformation (and by up to 10% for individual cases), the proposed FEM‐based method preserved CTV volumes throughout the deformation. Regional residual errors between repeat and library CTV reduced by up to 3 mm when averaged over the group of large movers. For individual cases this regional error reduction could be as large as 8 mm.ConclusionsWe developed a robust and automatic method to create a patient‐specific FEM‐based LoP. The FEM‐based method resulted in more accurate library of planning CTVs as compared to the current method, with the greatest improvements observed for patients with large CTV motion. The biomechanical model simulates volumetric deformations from empty to full bladder anatomy, paving the way for dose accumulation in an LoP setting.