bluuebunny/crossref_metadata_2025 huggingface dataset:
Base excision repair of DNA in mammalian cells
Authors: Krokan Hans E , Nilsen Hilde , Skorpen Frank , Otterlei Marit , Slupphaug Geir
Published: July 2002

Base excision repair (BER) of DNA corrects a number of spontaneous and environmentally induced genotoxic or miscoding base lesions in a process initiated by DNA glycosylases. An AP endonuclease cleaves at the 5′ side of the abasic site and the repair process is subsequently completed via either short patch repair or long patch repair, which largely require different proteins. As one example, the UNG gene encodes both nuclear (UNG2) and mitochondrial (UNG1) uracil DNA glycosylase and prevents accumulation of uracil in the genome. BER is likely to have a major role in preserving the integrity of DNA during evolution and may prevent cancer.
An Arabidopsis mutant cex1 exhibits constant accumulation of jasmonate‐regulated AtVSP, Thi2.1 and PDF1.2
Authors: Xu Linghui , Liu Fuquan , Wang Zhilong , Peng Wen , Huang Rongfeng , Huang Dafang , Xie Daoxin
Published: July 2002

Jasmonates (JA) act as a regulator in plant growth as well as a signal in plant defense. The Arabidopsis vegetative storage protein (AtVSP) and plant defense‐related proteins thionin (Thi2.1) and defensin (PDF1.2) have previously been shown to accumulate in response to JA induction. In this report, we isolated and characterized a novel recessive mutant, cex1, conferring constitutive JA‐responsive phenotypes including JA‐inhibitory growth and constitutive expression of JA‐regulated AtVSP, Thi2.1 and PDF1.2. The plant morphology and the gene expression pattern of the cex1 mutant could be phenocopied by treatment of wild‐type plants with exogenous JA, indicating that CEX1 might be a negative regulator of the JA response pathway.
Do mammalian cells synthesize lipoic acid?
Authors: Morikawa Toshimitsu , Yasuno Rie , Wada Hajime
Published: July 2002

Lipoic acid is a coenzyme essential to the activity of enzymes such as pyruvate dehydrogenase, which play important roles in central metabolism. However, neither the enzymes responsible for biosynthesis nor the biosynthetic event of lipoic acid has been reported in mammalian cells. In this study, a mouse mLIP1 cDNA for lipoic acid synthase has been identified. We have shown that the cDNA encodes a lipoic acid synthase by its ability to complement a mutant of Escherichia coli defective in lipoic acid synthase and that mLIP1 is targeted into the mitochondria. These findings suggest that mammalian cells are able to synthesize lipoic acid in mitochondria.
Shear stress inhibits apoptosis of human endothelial cells
Authors: Dimmeler Stefanie , Haendeler Judith , Rippmann Volker , Nehls Michael , Zeiher Andreas M.
Published: July 2002

Physiological levels of shear stress alter the genetic program of cultured endothelial cells and reduce endothelial cell turnover in vivo. To test the hypothesis that shear stress interferes with programmed cell death, apoptosis was induced in human umbilical venous endothelial cells by growth factor withdrawal or incubation with tumor necrosis factor α(TNFα) for 18 h. Apoptosis was quantified by ELISA specific for histone‐associated DNA fragments and confirmed by demonstrating the specific pattern of internucleosomal DNA fragmentation detected by electrophoresis and immunohistochemical staining. The TNFα (300 U/ml)‐mediated increase in DNA fragmentation was completely abrogated by shear stress. Furthermore, shear stress dose‐dependently reduced DNA fragmentation induced by growth factor withdrawal with maximal effect at 45 dyn/cm2. Inhibition of the CPP32‐like proteases with Ac‐DEVD‐CHO (100 μM) revealed similar anti‐apoptotic effects. In contrast, CPP32‐independent induction of endothelial cell apoptosis by C2‐ceramide (50 μM) was not prevented by shear stress. Thus, we propose that shear stress interferes with common cell death signal transduction involving the CPP32‐like protease family and may contribute to endothelial cell integrity by inhibition of apoptosis.
Single‐strand‐specific DNase activity is an inherent property of the 140‐kDa protein of the snake venom exonuclease1
Authors: Stoynov Stoyno S , Bakalova Anastassia T , Dimov Svetoslav I , Mitkova Atanaska V , Dolapchiev Luben B
Published: July 2002

Polyclonal antibodies against the exonuclease from Crotalus adamanteus venom (the 140‐kDa protein) inhibit both the exonucleolytic and the single‐strand‐specific endonucleolytic activities, present in the exonuclease preparation. The antibodies also diminish the ability of the enzyme to split the negatively supercoiled Bluescript KS+ in the AT‐rich fragment near‐by the transcription termination site of the Ampicillin gene. Therefore the single‐strand‐specific endonucleolytic activity was attributed to the protein molecule of the exonuclease. The processivity of the exonucleolytic action was found to be less than 3 monomers as indicated by the heparin trapping method.
The yeast mic2 mutant is defective in the formation of mannosyl‐diinositolphosphorylceramide1
Authors: Leber Andrea , Fischer Petra , Schneiter Roger , Kohlwein Sepp D. , Daum Günther
Published: July 2002

The mic2 mutation dominantly blocks formation of mannosyl‐diinositolphosphorylceramide, the most abundant sphingolipid of the yeast, Saccharomyces cerevisiae. Interestingly, lack of mannosyl‐diinositolphosphorylceramide is not lethal but is compensated for by increased amounts of inositolphosphorylceramide and mannosyl‐inositolphosphorylceramide in the plasma membrane and Golgi of the mutant. The level of negatively charged phospholipids in the plasma membrane of the mic2 strain is markedly reduced; the sterol composition is not altered. In spite of dramatic changes of its lipid composition the mutant grows like wild type on complex and minimal media, under osmotic stress conditions, at low pH, and in the presence of high ionic strength. While sensitivity to several drugs is not altered, the mic2 mutant strain becomes resistant to the polyene antibiotic nystatin.
The acetyl‐CoA synthetase gene ACS2 of the yeast Saccharomyces cerevisiae is coregulated with structural genes of fatty acid biosynthesis by the transcriptional activators Ino2p and Ino4p
Authors: Hiesinger Margit , Wagner Christian , Schüller Hans-Joachim
Published: July 2002

The yeast Saccharomyces cerevisiae contains two acetyl‐CoA synthetase genes, ACS1 and ACS2. While ACS1 transcription is glucose repressible, ACS2 shows coregulation with structural genes of fatty acid biosynthesis. The ACS2 upstream region contains an ICRE (inositol/choline‐responsive element) as an activating sequence and requires the regulatory genes INO2 and INO4 for maximal expression. We demonstrate in vitro binding of the heterodimeric activator protein Ino2p/Ino4p to the ACS2 promoter. In addition, the pleiotropic transcription factor Abf1p also binds to the ACS2 control region. The identification of ACS2 activating elements also found upstream of ACC1, FAS1 and FAS2 suggests a role of this acetyl‐CoA synthetase isoenzyme for the generation of the acetyl‐CoA pool required for fatty acid biosynthesis.
Opposite effects of cell differentiation and apoptosis on Ap3A/Ap4A ratio in human cell cultures
Authors: Vartanian Amalia , Prudovsky Igor , Suzuki Hisanori , Dal Pra Ilaria , Kisselev Lev
Published: July 2002

The biological role of diadenosine oligophosphates (DAOP) remains obscure in spite of numerous attempts to solve this enigma. It is known that Ap3A contrary to Ap4A accumulates in human cultured cells treated with interferons (IFNs) alpha or gamma. Since IFNs are considered as antiproliferative regulators, we assumed that different cell status may be associated with varying intracellular levels of DAOP. Promyelocytic human cell line HL60 induced by phorbol ester (TPA) to differentiate to macrophage‐like cells in culture exhibits a profound loss of proliferative potential. Here we have shown a 4–5‐fold increase in Ap3A concentration in HL60 cells induced by TPA, similar to the effect of IFN, while the Ap4A concentration remained unchanged. On the contrary, in cells undergoing apoptosis induced by VP16, a topoisomerase II inhibitor, the Ap3A concentration considerably decreased, while the Ap4A concentration increased. These findings combined with earlier results suggest an involvement of the Ap3A/Ap4A ratio in signal transduction pathways controlling the cell status.
Genotyping of human cytochrome P450 2A6 (CYP2A6), a nicotine C‐oxidase
Authors: Oscarson Mikael , Gullstén Harriet , Rautio Arja , Bernal Maria Luisa , Sinues Blanca , Dahl Marja-Liisa , Stengård Jari H , Pelkonen Olavi , Raunio Hannu , Ingelman-Sundberg Magnus
Published: July 2002

Cytochrome P450 2A6 (CYP2A6) is a polymorphic enzyme responsible for the oxidation of certain precarcinogens and drugs and is the major nicotine C‐oxidase. The role of CYP2A6 for nicotine elimination was emphasised recently by the finding that smokers carrying defective CYP2A6 alleles consumed fewer cigarettes [Pianezza et al. (1998) Nature 393, 750]. The method used for CYP2A6 genotyping has, however, been found to give erroneous results with respect to the coumarin hydroxylase phenotype, a probe reaction for the CYP2A6 enzyme. The present study describes an allele‐specific PCR genotyping method that identifies the major defective CYP2A6 allele and accurately predicts the phenotype. An allele frequency of 1–3% was observed in Finnish, Spanish, and Swedish populations, much lower than described previously.
HMG‐CoA reductase inhibitor‐induced L6 myoblast cell death: involvement of the phosphatidylinositol 3‐kinase pathway
Authors: Nakagawa Hiroto , Mutoh Tatsuro , Kumano Takanori , Kuriyama Masaru
Published: July 2002

Our previous studies have shown that the HMG‐CoA reductase inhibitor (HCRI) causes rhabdomyolysis and electrical myotonia in rabbits and also kills L6 myoblasts in culture. In the present study, we analyzed the intracellular signal transduction pathway of HCRI‐induced cell death using L6 myoblasts as a model system. Here, we report that simvastatin, a lipophilic HCRI, efficiently inhibited isoprenylation of Ras proteins and therefore induced translocation of a significant part of Ras proteins from the membrane fraction into the cytosolic fraction within 10 min. With this translocation, PI 3‐kinase activity of the Ras‐bound form both in total and in the membrane fraction was also decreased profoundly. Furthermore, various PI 3‐kinase inhibitors also caused cell death with morphological changes similar to those caused by simvastatin. These results might represent the molecular events of HCRI‐induced cell death, and suggest the significance of PI 3‐kinase activity of the Ras‐bound form in the maintenance of cell viability.
Thiol‐dependent degradation of protoporphyrin IX by plant peroxidases
Authors: Dayan F.E , Rimando A.M , Duke S.O , Jacobs N.J
Published: July 2002

Protoporphyrin IX (PP) is the last porphyrin intermediate in common between heme and chlorophyll biosynthesis. This pigment normally does not accumulate in plants because its highly photodynamic nature makes it toxic. While the steps leading to heme and chlorophylls are well characterized, relatively little is known of the metabolic fate of excess PP in plants. We have discovered that plant peroxidases can rapidly degrade this pigment in the presence of thiol‐containing substrates such as glutathione and cysteine. This thiol‐dependent degradation of PP by horseradish peroxidase consumes oxygen and is inhibited by ascorbic acid.
Artificial antifreeze polypeptides: α‐helical peptides with KAAK motifs have antifreeze and ice crystal morphology modifying properties
Authors: Zhang Wei , Laursen Richard A.
Published: July 2002

Antifreeze polypeptides from fish are generally thought to inhibit ice crystal growth by specific adsorption onto ice surfaces and preventing addition of water molecules to the ice lattice. Recent studies have suggested that this adsorption results from hydrogen bonding through the side chains of polar amino acids as well as hydrophobic interactions between the non‐polar domains on the ice‐binding side of antifreeze polypeptides and the clathrate‐like surfaces of ice. In order to better understand the activity of one of the antifreeze polypeptide families, namely the α‐helical type I antifreeze polypeptides, four α‐helical peptides having sequences not directly analogous to those of known antifreeze polypeptides and containing only positively charged and non‐polar side chains were synthesized. Two peptides with regularly spaced lysine residues, GAAKAAKAAAAAAAKAAKAAAAAAAKAAKAAGGY‐NH2 and GAALKAAKAAAAAALKAAKAAAAAALKAAKAAGGY‐NH2, showed antifreeze activity, albeit weaker than seen in natural antifreeze polypeptides, by the criteria of freezing point depression (thermal hysteresis) and ice crystal modification to a hexagonal trapezohedron. Peptides with irregular spacing of Lys residues were completely inactive. Up to now, lysine residues have not been generally associated with antifreeze activity, though they have been implicated in some antifreeze polypeptides. This work also shows that lysine residues in themselves, when properly positioned on an α‐helical polyalanine scaffold, have all the requisite properties needed for such an activity.
Involvement of branched‐chain amino acid aminotransferase (Bcat1/Eca39) in apoptosis
Authors: Eden Amir , Benvenisty Nissim
Published: July 2002

The branched‐chain amino acid aminotransferase, Bcat1/Eca39, catalyzes the first step of branched‐chain amino acid catabolism. Bcat1/Eca39 was originally isolated from a c‐myc‐induced tumor and was proven to be a direct target for c‐Myc regulation. The gene is highly conserved in evolution and disruption of its yeast homolog affects cell growth. To assess the role of Bcat1/Eca39 in mammalian cells, we overexpressed Bcat1/Eca39 in murine cells and studied effects on cell growth. Overexpression of Bcat1/Eca39 had no apparent effect on the proliferation of cells grown with high serum concentrations, but under serum deprivation conditions, led to a decrease in cell viability. Cell death under these conditions displayed apoptotic features. The branched‐chain keto acid, α‐ketoisocaproate, a metabolite of leucine catabolism produced by BCAT1/ECA39, was previously found to inhibit cell growth. We show that α‐ketoisocaproate can induce rapid apoptotic cell death. This observation suggests that the growth inhibitory effect of BCAT1/ECA39 and its apoptosis promoting effect may be mediated by the levels of the products of BCAT1/ECA39 activity, namely, branched‐chain keto acids.
Potential role of 3‐phosphoinositide‐dependent protein kinase 1 (PDK1) in insulin‐stimulated glucose transporter 4 translocation in adipocytes
Authors: Grillo Sophie , Grémeaux Thierry , Le Marchand-Brustel Yannick , Tanti Jean-François
Published: July 2002

Insulin stimulation of Glut 4 translocation requires the activation of phosphatidylinositol 3‐kinase (PI 3‐kinase) but the downstream pathway remains ill‐defined. We demonstrated that the overexpression of PDK1 (3‐phosphoinositide‐dependent protein kinase 1), a downstream effector of PI 3‐kinase, stimulated Glut 4 translocation in adipocytes. This effect does not require the PH domain of PDK1, but expression of the pleckstrin homology domain‐deleted PDK1 inhibits the effect of insulin, but not okadaic acid, on Glut 4 translocation. These results support a role of the PDK1 pathway in the transmission of insulin signal to Glut translocation.
Doppler echocardiography reliably predicts pulmonary artery wedge pressure in patients with chronic heart failure even when atrial fibrillation is present
Authors: Traversi Egidio , Cobelli Franco , Pozzoli Massimo
Published: July 2002

Background and aims:

In patients with chronic congestive heart failure a high pulmonary artery wedge pressure (PAWP) is associated with poor prognosis, severe symptoms and low exercise tolerance. When atrial fibrillation is present the non‐invasive prediction of PAWP by Doppler echocardiography is generally considered to be not reliable.

Methods:

In 51 consecutive patients with chronic heart failure, due to either ischemic and non‐ischemic dilated cardiomyopathy, and atrial fibrillation simultaneous Doppler echocardiographic and hemodynamic studies were used to estimate PAWP. The power of the obtained multivariate equation was compared with that of previously developed equations and was then prospectively tested in a group of 15 patients.

Results:

The deceleration rate (DR) of early diastolic mitral flow, the left ventricular iso‐volumic relaxation time (IVRT) and the systolic fraction of pulmonary venous flow (SF) were independent predictors of PAWP and the following multivariable equation was derived: PAWP ‐ 24.04 + 1.23 × DR − 0.089 × IVRT − 0.175 × SF. The correlation between invasive PAWP and the PAWP non‐invasively estimated by this equation in the testing group was 0.91 (standard error of estimate ‐ 3.2 mmHg). The mean difference was 0.93 and the standard error of differences was 2.7 mmHg.

Conclusion:

In patients with chronic heart failure due to dilated cardiomyopathy who are in atrial fibrillation a relatively accurate estimation of PAWP can be obtained by Doppler echocardiography of mitral and pulmonary venous flow.
Gradiently Sodiated Alucone as an Interfacial Stabilizing Strategy for Solid‐State Na Metal Batteries
Authors: Zhang Shumin , Zhao Yang , Zhao Feipeng , Zhang Long , Wang Changhong , Li Xiaona , Liang Jianwen , Li Weihan , Sun Qian , Yu Chuang , Luo Jing , Doyle‐Davis Kieran , Li Ruying , Sham Tsun‐Kong , Sun Xueliang
Published: April 2020

All‐solid‐state metal batteries (ASSMBs) are attracting much attention due to their cost effectiveness, enhanced safety, room‐temperature performance and high theoretical specific capacity. However, the alkali metal anodes (such as Li and Na) are active enough to react with most solid‐state electrolytes (SSEs), leading to detrimental reactions at the metal–SSE interface. In this work, a molecular layer deposition (MLD) alucone film is employed to stabilize the active Na anode/electrolyte interface in the ASSMBs, limiting the decomposition of the sulfide‐based electrolytes (Na3SbS4 and Na3PS4) and Na dendrite growth. Such a strategy effectively improves the room‐temperature full battery performance as well as cycling stability for over 475 h in Na–Na symmetric cells. The modified interface is further characterized by X‐ray photoelectron spectroscopy (XPS) depth profiling, which provides spatially resolved evidence of the synergistic effect between the dendrite‐suppressed sodiated alucone and the insulating unsodiated alucone. The coupled layers reinforce the protection of the Na metal/electrolyte interface. Therefore, alucone is identified as an effective and bifunctional coating material for the enhancement of the metal/electrolyte interfacial stability, paving the way for rapid development and wide application of high‐energy ASSMBs.
Hydrosilylation of Aldehydes and Ketones Catalysed by Bis(phosphinite) Pincer Platinum Hydride Complexes
Authors: Chang Jiarui , Fang Fei , Zhang Jie , Chen Xuenian
Published: April 2020

Bis(phosphinite) pincer platinum hydride complexes, [2,6‐(R2PO)2C6H3]PtH (R=tBu, iPr), were synthesized, characterized and applied to the hydrosilylation of aldehydes and ketones. NMR study and single crystal X‐ray diffraction analysis indicated that the hydrides in these two platinum complexes are comparatively less hydridic: down‐field 1H NMR resonances (0.71 and 0.98 ppm) and weak Pt−H interactions were observed. Both the platinum complexes were found to be good catalysts for the hydrosilylation of aldehydes and ketones with phenylsilane. The corresponding alcohols were isolated in good to excellent yields following basic hydrolysis of the resultant hydrosilylation products and turnover frequencies (TOFs) up to 3200 h−1 were achieved at 60 °C in toluene, which are much higher than those of the hydrosilylation catalysed by the corresponding nickel pincer hydride complexes. A possible mechanism for the present hydrosilylation process was discussed.

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Multiple synostoses syndrome: Clinical report and retrospective analysis
Authors: Pan Zhaoyu , Lu Wei , Li Xiaohong , Huang Shasha , Dai Pu , Yuan Yongyi
Published: April 2020

Multiple synostoses syndrome (SYNS1; OMIM# 186500) is a rare autosomal dominant disorder reported in a few cases worldwide. We report a Chinese pedigree characterized by proximal symphalangism, conductive hearing loss, and distinctive facies. We examined the genetic cause and reviewed the literature to discuss the pathogeny, treatment, and prevention of SYNS1. Audiological, ophthalmological, and radiological examinations were evaluated. Whole‐exome sequencing (WES) was performed to identify mutations in the proband and her parents. Sanger sequencing was used to verify the results for the proband, parents, and grandmother. The literature on the genotype–phenotype correlation was reviewed. The patient was diagnosed with multiple synostoses syndrome clinically. WES and bioinformatic analysis revealed a novel missense mutation in the NOG gene, c.554C>G (p.Ser185Cys), cosegregated in this family. The literature review showed that the phenotype varies widely, but the typical facies, conductive hearing loss, and proximal symphalangism occurred frequently. All reported mutations are highly conserved in mammals based on conservation analysis, and there are regional hot spots for these mutations. However, no distinct genotype–phenotype correlations have been identified for mutations in NOG in different races. Regular systematic examinations and hearing aids are beneficial for this syndrome. However, the outcomes of otomicrosurgery are not encouraging owing to the regrowth of bone. This study expanded the mutation spectrum of NOG and is the first report of SYNS1 in a Chinese family. Genetic testing is recommended as part of the diagnosis of syndromic deafness. A clinical genetic evaluation is essential to guide prevention, such as preimplantation genetic diagnosis.
Enhanced hydroformylation of 1‐hexene in microbubble media
Authors: Peng Fei , Zhang Jie , Tang Zhiyong , Sun Yuhan
Published: April 2020

To enhance the gas–liquid mass transfer in the hydroformylation reaction, microbubbles were applied into this typical gas–liquid reaction. Compared with a commercial tube microbubble generator, a fractal microbubble distributor, which was designed based on the bionic fractal theory and manufactured via 3D printing, permitted to increase the total microbubble number and decrease the microbubble size. Moreover, the microbubbles were more uniformly distributed in the reactor by the fractal distributor. The gas holdup and the gas–liquid mass transfer were much higher in microbubble system than those with millimeter bubbles. The microbubble status played an important role on the hydroformylation performance. With a close total aldehyde yield (90%), the introduction of microbubbles could reduce the hydroformylation reaction time from 120 min of the stirred batch reactor to 60 min owing to the enhanced mass transfer. The proposed microbubble mediated system also has great potential for intensifying the other gas–liquid reactions.
Bauzeitenvorhersage von Injektionen im Tunnelbau
Authors: Backhaus Jan Onne
Published: April 2020

In diesem Beitrag wird eine Methode vorgestellt, die die digitale Dokumentation auf Injektionsbaustellen nutzt, um automatisierte, baubegleitende Bauzeitenvorhersagen zu berechnen. Es wird gezeigt, dass die Genauigkeit der Vorhersagen jener von bisher üblichen händischen Vorhersagemethoden deutlich überlegen sein kann. Hierbei werden traditionelle statistische Methoden und Markow‐Ketten innerhalb einer diskreten Ereignissimulation verwendet, um hypothetische Projektverläufe zu berechnen. Diese werden mit einer Monte‐Carlo‐Simulation in eine Vorhersage für die Gesamtbauzeit überführt. Die Daten wurden von der Renesco GmbH in Zusammenarbeit mit der eguana GmbH erhoben.
Screening and identification of resistant sources against Sclerotinia sclerotiorum causing white mold disease in common bean
Authors: Chauhan Sonali , Katoch Shabnam , Sharma S.K. , Sharma P.N. , Rana J.C. , Singh Kuldeep , Singh Mohar
Published: April 2020

White mold caused by Sclerotinia sclerotiorum (Lib.) de Bary is a devastating constraint in common bean (Phaseolus vulgaris L.) production, affecting plants at both seedling and adult stages. Being a crop of small‐area, resource‐poor, farmers and given the high cost of fungicides, farmers prefer the use of region‐specific landraces or resistant accessions. In this study, we compared various methods of bean plant inoculation with S. sclerotiorum and found modified straw test method of inoculation as most accurate and effective. Using this method, we screened a panel of 516 common bean germplasm procured from 22 countries through the National Bureau of Plant Genetic Resources (NBPGR; New Delhi, India) against white mold pathogen. Only 12 accessions were found resistant, whereas 121 were moderately resistant to white mold. Among exotic resistant accessions, EC271515, EC271475, EC271523, and EC271528 were from the Colombian region, while the remaining four, EC530910, EC530913, EC530916, and EC531044, belonged to Columbia. Of the four resistant landraces from India, IC280353 was a collection from Jammu and Kashmir State, whereas landraces IC278744, IC278709, and IC278734 were from Himachal Pradesh. Considering the area under disease progress curve (AUDPC), incubation period, infection rate, and lesion length, EC‐271475 followed by EC‐530916 were concluded to be the best accessions against white mold. Further, the statistical analysis also confirms the highly resistant nature of phenotypically screened common bean accessions. One exotic accession, EC271475, possessing resistance to S. sclerotiorum was also resistant to bean common mosaic virus (BCMV) strain NL‐7n and could be used in common bean breeding programs.
Balancing aspects of numerical dissipation, dispersion, and aliasing in time‐accurate simulations
Authors: Edoh Ayaboe K. , Mundis Nathan L. , Karagozian Ann R. , Sankaran Venkateswaran
Published: April 2020

The current study looks at the selection of scheme elements that are well‐suited for long‐time integration of unsteady flows in the absence or under‐resolution of physical diffusion. A concerted assembly of numerical components are chosen relative to a target aliasing limit, which is taken as a best‐case scenario for overall spectral resolvability. High‐order and optimized difference stencils are employed in order to achieve accuracy; meanwhile, quasi skew‐symmetric splitting techniques for nonlinear transport terms are used in order to greatly improve robustness. Finally, tunable and scale‐discriminant artificial‐dissipation methods are incorporated for de‐aliasing purposes and as a means of further enhancing both accuracy and stability. Central finite difference methods are considered, and spectral characterizations of the scheme components are presented. Canonical test cases (the isentropic vortex [IV] and Taylor‐Green vortex problems) are chosen in order to highlight the benefits associated with the proposed approach for enhancing overall algorithm robustness and accuracy.
A comparison of methods to estimate groundwater recharge from bare soil based on data observed by a large‐scale lysimeter
Authors: Zhang Zaiyong , Wang Wenke , Gong Chengcheng , Zhang Ming
Published: April 2020

Effectively estimating groundwater recharge is critical to manage water resources, especially in arid and semi‐arid regions as impacted by intensive human activities and climate changes. Rare insights have been gained into groundwater recharge since direct observation is hard to carry out. Although several methods are currently available to estimate groundwater recharge, the estimated results may cover noticeable bias. The behaviours of different methods based on different conceptual frameworks and exhibiting different levels of complexity should be examined to estimate actual groundwater recharge. This study aims to assess the performance of four common methods to estimate groundwater recharge. For this end, large‐scale lysimeters equipped with soil water content sensors and water table sensors were set up at a research site established in Guanzhong Basin of China. The data achieved by 1‐year observation were employed to compare four estimation methods. As revealed from the results, the following findings are drawn. (a) Groundwater level fluctuation (GLF) method is simple, whereas its accuracy is determined by specific yield, and adopting a water balance method to estimate specific yield can considerably enhance the accuracy of GLF. (b) The calibrated numerical model can obtain the optimal result compared with the other methods, whereas long‐term observation data are required for parameter calibration. (c) In the water balance method, the maximum entropy production (MEP) model and a practical method (estimating evaporation between two rainfall events) were used to calculate evaporation. As indicated by the results, water balance method combined with MEP is capable of obtaining more reliable results of groundwater recharge compared with the practical method. (d) With an analytical model based on linearized Richards' equation, accurate results can be achieved. What is more, the analytical model only needs the measurement of soil moisture near the surface. The limitation of this method is that it is difficult to determine the maximal water flux. The mentioned findings are of critical implications to the management and sustainable development of groundwater.
A monthly regression correction model for the Hargreaves–Samani method in Mainland China
Authors: Xia Xingsheng , Zhu Xiufang , Pan Yaozhong , Zhang Jinshui
Published: April 2020

Reference crop evapotranspiration (ET0) is an important parameter for irrigation engineering. It can be calculated using the Penman–Monteith method (PM), which results in ET0‐PM. This study uses ET0‐PM to determine the availability of a monthly linear regression correction model for the Hargreaves–Samani method (HG). The data were obtained from 647 meteorological stations in mainland China, which are contained within the data set of monthly values of climate data from Chinese surface stations. For most stations, the correlation coefficient of ET0‐PM and ET0‐HG (determined by the HG method) ranges from 0.5 to 1.0. This provides the necessary conditions for the monthly linear regression correction of ET0‐HG. The mean relative change of the mean absolute error before and after the ET0‐HG correction for each year indicates that the scheme adopted in this study yields improved correction results during autumn, winter and spring in mainland China and poor results during summer. However, the monthly regression correction model for the HG is only available for part of the stations in each season. This study supplements a case for the larger‐scale ET0‐HG monthly regression correction. This can be a reference for the further refinement of the ET0‐HG spatio‐temporal correction © 2020 John Wiley & Sons, Ltd.
Reduced basis method for managed pressure drilling based on a model with local nonlinearities
Authors: Abbasi Mohammad Hossein , Iapichino Laura , Naderi Lordejani Sajad , Schilders Wil , van de Wouw Nathan
Published: April 2020

To circumvent restrictions of conventional drilling methods, such as slow control actions and inability to drill depleted reservoirs, a drilling method called managed pressure drilling (MPD) has been developed. In MPD, single‐phase flow processes can be modeled as a feedback interconnection of a high‐order linear system and a low‐order nonlinear system. These nonlinearities appear locally both inside and at the boundaries of the computational domain. To obtain a fast simulation platform for real‐time purposes (eg, online model‐based controller implementation), model order reduction is required for MPD. However, the local nonlinearities render applying model order reduction techniques challenging. In this study, a new approach is proposed to deal with such nonlinearities within the reduced basis (RB) context and it is successfully tested on a model for MPD. Contrary to the classical RB technique, the proposed approach not only does not generate nonphysical spikes at the locations of these local nonlinearities but also yields high speedup factors. The obtained reduced‐order model can be used for efficient online simulation and controller design for drilling systems with
MPD.
Registration of Hessian fly‐resistant germplasm KS18WGRC65 carrying H26 in hard red winter wheat ‘Overley’ background
Authors: Singh Narinder , Steeves Ryan , Chen Ming‐Shun , Bouhssini Mustapha El , Pumphrey Michael , Poland Jesse
Published: April 2020

Hessian fly (HF; Mayetiola destructor Say) causes severe damage to wheat (Triticum aestivum L.) worldwide. Several resistance genes have been identified in wheat and wild relatives; however, HF populations are under strong selection pressure and evolve rapidly to overcome resistance. To ensure the availability of resistance sources, HF‐resistant germplasm KS18WGRC65 (TA5110, Reg. no. GP‐1042, PI 688251) was developed by Wheat Genetics Resource Center at Kansas State University as a breeding stock that carries resistance gene H26 from Aegilops tauschii Coss. KS18WGRC65 is a cytogenetically stable, homozygous, BC3F3:6 line derived from the cross between Ae. tauschii accession KU2147 and hard red winter wheat recurrent parent ‘Overley’. KS18WGRC65 exhibited no penalty for yield or other agronomic characters, making it a suitable source of HF resistance for wheat breeding.
Reduction of harmonic current distortion for single‐phase grid‐tied inverter operated in discontinuous current mode
Authors: Zhang JianTao , Isobe Takanori , Tadano Hiroshi
Published: April 2020

Discontinuous current mode (DCM) with high‐frequency operation can be an effective way to reduce the volume of inductors for low‐power grid‐tied inverter applications. Unlike the controllers designed for continuous current mode operations, current controllers for DCM are required to address their nonlinear characteristics. A feed‐forward controller can be a good choice for the current control of the grid‐tied inverters operated in DCM. However, distortions in the output current cannot be eliminated, and they can be more severe if devices with large output capacitance are applied. Two harmonic current reduction strategies, namely a partial feedback path and an improved modulation, are proposed to reduce the low‐ and high‐order harmonics for single‐phase grid‐tied inverters operated in DCM. The proposed strategies are discussed and verified by a laboratory prototype in some experiments. It is indicated that the proposed modulation can mitigate the influence of device parasitic capacitance on current distortion and expand the device selections. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Failure of the N‐wave interaction approximation without imposing periodic boundary conditions
Authors: Haas Tobias , Schneider Guido
Published: April 2020

The N‐wave interaction (NWI) system appears as an amplitude system in the description of N nonlinearly interacting and linearly transported wave packets in dispersive wave systems such as the water wave problem or problems in nonlinear optics. The purpose of this paper is twofold. First we give a new simplified proof for the failure of the NWI approximation in case of resonances which are located at integer multiples of a basic wave number k0 in the original ‐spatially periodic dispersive wave system. Secondly, we give a first rigorous proof that an amplitude system fails in the description of an original system, without imposing periodic boundary conditions on the original system.
Consequences of mandated usage of innovations in organizations: developing an innovation decision model of symbolic and forced adoption
Authors: Heidenreich Sven , Talke Katrin
Published: April 2020

In organizations, mandated adoption contexts are the rule rather than the exception. Individuals, who are denied the choice between adopting and rejecting an innovation, are more likely to engage in opposition behavior, particularly if the innovation conflicts with their held beliefs. Interestingly, neither the construct of forced adoption nor its consequences have received much research attention. To address this gap, we conduct a systematic literature review and provide theoretical rationales for the emergence of innovation resistance and opposition behaviors in organizations. We then develop an innovation decision model of individual adoption behavior that localizes negative outcomes of the secondary adoption process along the different process stages, providing insights into their emergence and potential consequences for the organization. Furthermore, we identify important avenues for future research and show how our innovation decision model can be used to advance theory development on forced adoption.
Chandra view on the active nucleus of CGCG 292–057: Jet-ISM interactions
Authors: Balasubramaniam K. , Stawarz Ł. , Marchenko V. , Thimmappa R. , Sobolewska M. , Siemiginowska A. , Cheung C. C. , Kozieł-Wierzbowska D. , Jamrozy M.
Published: April 2020

We present the analysis of the 93 ksec Chandra ACIS–S data for the galaxy CGCG 292–057 (z = 0.054), with complex radio structure indicative of the intermittent jet activity. In order to characterize precisely the spectrum of the unresolved low-luminosity active nucleus in the source, we performed detailed MARX/PSF simulations and studied the radial profile of the source region surface brightness. In this way, we have detected an additional X-ray component extending from a few up to ∼10 kpc from the unresolved core, which could be associated with the hot gaseous medium compressed and heated (up to 0.9 keV) by the expanding inner lobes of the radio galaxy. We modeled the X-ray spectrum of the unresolved nucleus assuming various emission models, including an absorbed power-law, a power-law plus thermal emission component, and a two-temperature thermal plasma. The best fit was however obtained assuming a power-law emission scattered by a hot ionized gas, giving rise to the 6.7 keV iron line.
Magnetic Fields in the Relativistic Jets of Active Galactic Nuclei
Authors: Gabuzda Denise C.
Published: April 2020

An abundance of information about the magnetic (B) fields of relativistic AGN jets has been obtained through radio polarization observations made on a wide range of scales, from the parsec scales probed by Very Long Baseline Interferometry to the kiloparsec scales probed by instruments such as the the Jansky Very Large Array and e-MERLIN. The observed radio emission is synchrotron radiation, for which the linear polarization angles in optically thin regions is orthogonal to the local synchrotron B fields. The characteristic B field structures observed for these jets on parsec scales are described. A key question is whether B field structures observed in particular AGN jets come about primarily due to “global” effects such as the intrinsic B field of the jet itself, which is expected to be helical, or local phenomena such as shocks, shear and bending of the jets. Observational criteria that can be used to try to distinguish between various possible origins for observed B field structures are described. There is now considerable evidence that the relativistic jets of AGNs do indeed carry helical B fields, with the observed polarization also sometimes appreciably influenced by local effects. Patterns seen in the helical B field components, indicated for example by Faraday rotation observations, provide unique information about the processes involved in the generation of these helical B fields. The collected observations on parsec and kiloparsec scales provide weighty evidence that an important role is played by the action of a cosmic “battery” that acts to generate an inward current along the jet axis and an outward current in a more extended region surrounding the jet.
Expanding Radio Lobe associated with 3C 84
Authors: Asada Keiichi , Inoue Makoto , Nagai Hiroshi , Kameno Seiji
Published: April 2020

Following the discovery of the expansion of a young radio lobe associated with the bright radio source 3C 84 in the Seyfert galaxy NGC 1275 using VSOP monitoring observation with duration of 3 years, we further investigated its evolution by utilizing VLBA monitoring data taken by MOJAVE project. As the results, we confirmed the expanding motion of both the southern and northern lobes, and detected side-way expanding motions for the first time. In meantime, the total flux density of the lobes are decreasing, while total flux density associated with the nuclei is significantly increasing. This cooling of the radio lobe can be well-explained with the energy loss through the adiabatic cooling.
Numerical and experimental analysis of a transmission-based breast imaging system: a study of application to patients
Authors: Norouzzadeh Elham , Chamaani Somayyeh , Moll Jochen , Kexel Christian , Nguyen Duy Hai , Hübner Frank , Bazrafshan Babak , Vogl Thomas J. , Krozer Viktor
Published: April 2020

Early detection of breast cancer is required to increase the chances of a successful treatment. However, current breast-imaging systems such as X-Ray mammography, breast ultrasound, and magnetic resonance imaging have technological limitations so that novel solutions are needed to address this major societal problem. The current paper considers ultra-wideband (UWB) microwave radiation in the frequency band from 1 to 9 GHz. Given by the non-ionizing nature of microwaves frequent check-ups are more feasible. In this work, we propose algorithms for qualitative and quantitative microwave breast imaging for a transmission-based UWB system. Based on numerical and experimental data, the performance of the algorithms has been investigated and compared. Finally, microwave images obtained during an initial patient study are discussed relative to corresponding X-ray images.
Real-space imaging of confined magnetic skyrmion tubes
Authors: Birch M. T. , Cortés-Ortuño D. , Turnbull L. A. , Wilson M. N. , Groß F. , Träger N. , Laurenson A. , Bukin N. , Moody S. H. , Weigand M. , Schütz G. , Popescu H. , Fan R. , Steadman P. , Verezhak J. A. T. , Balakrishnan G. , Loudon J. C. , Twitchett-Harrison A. C. , Hovorka O. , Fangohr H. , Ogrin F. Y. , Gräfe J. , Hatton P. D.
Published: April 2020

Magnetic skyrmions are topologically nontrivial particles with a potential application as information elements in future spintronic device architectures. While they are commonly portrayed as two dimensional objects, in reality magnetic skyrmions are thought to exist as elongated, tube-like objects extending through the thickness of the host material. The study of this skyrmion tube state (SkT) is vital for furthering the understanding of skyrmion formation and dynamics for future applications. However, direct experimental imaging of skyrmion tubes has yet to be reported. Here, we demonstrate the real-space observation of skyrmion tubes in a lamella of FeGe using resonant magnetic x-ray imaging and comparative micromagnetic simulations, confirming their extended structure. The formation of these structures at the edge of the sample highlights the importance of confinement and edge effects in the stabilisation of the SkT state, opening the door to further investigation into this unexplored dimension of the skyrmion spin texture.
Publisher Correction: Multi-resolution localization of causal variants across the genome
Authors: Sesia Matteo , Katsevich Eugene , Bates Stephen , Candès Emmanuel , Sabatti Chiara
Published: April 2020

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Combination of highly efficient microflora to degrade paint spray exhaust gas
Authors: Lan Huixia , Qi Shixin , Yang Da , Zhang Heng , Liu Jianbo , Sun Yanhui
Published: April 2020

Spray paint exhaust gas contains recalcitrant volatile organic compounds (VOCs), such as benzene, toluene and xylene (BTX). Treating BTX with a biofilter often achieves unsatisfactory results because the biofilter lacks efficient microbial community. In this work, three strains for BTX degradation were isolated and identified as Pseudomonas putida, Bacillus cereus and Bacillus subtilis by using 16S rRNA sequencing technology. A consortium of highly efficient microbial community was then constructed on a stable biofilm to treat BTX in a biofilter. A relatively suitable ratio of P. putida, B. cereus and B. subtilis was obtained. An efficiency of over 90% was achieved in the biofilter with VOC concentration of 1000 mg/m3 through inoculation with the microbial community after only 10 days of operation. Thus, fast start-up of the biofilter was realised. Analysis of intermediate products by gas chromatography–mass spectrometry indicated that BTX was degraded into short-chain aldehydes or acids via ring opening reactions.
Glutathione S-transferasesP1 AA (105Ile) allele increases oral cancer risk, interacts strongly with c-Jun Kinase and weakly detoxifies areca-nut metabolites
Authors: Yadav Pallavi , Banerjee Atanu , Boruah Nabamita , Singh Chongtham Sovachandra , Chatterjee Puja , Mukherjee Souvik , Dakhar Hughbert , Nongrum Henry B. , Bhattacharjee Atanu , Chatterjee Anupam
Published: April 2020

The Glutathione S-transferases (GSTs) protects cellular DNA against oxidative damage. The role of GSTP1 polymorphism (A313G; Ile105Val) as a susceptibility factor in oral cancer was evaluated in a hospital-based case-control study in North-East India, because the habit of chewing raw areca-nut (RAN) with/without tobacco is common in this region. Genetic polymorphism was investigated by genotyping 445 cases and 444 controls. Individuals with the GSTP1 AA-genotype showed association with the oral cancer (OR = 3.1, 95% CI = 2.4–4.2, p = 0.0002). Even after adjusting for age, sex and habit the AA-genotype is found to be significantly associated with oral cancer (OR = 2.4, 95% CI = 1.7–3.2, p = 0.0001). A protein-protein docking analysis demonstrated that in the GG-genotype the binding geometry between c-Jun Kinase and GSTP1 was disrupted. It was validated by immunohistochemistry in human samples, showing lower c-Jun-phosphorylation and down-regulation of pro-apoptotic genes in normal oral epithelial cells with the AA-genotype. In silico docking revealed that AA-genotype weakly detoxifies the RAN/tobacco metabolites. In addition, experiments revealed a higher level of 8-Oxo-2′-deoxyguanosine induction in tumor samples with the AA-genotype. Thus, habit of using RAN/tobacco and GSTP1 AA-genotype together play a significant role in predisposition to oral cancer risk by showing higher DNA-lesions and lower c-Jun phosphorylation that may inhibit apoptosis.