bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Gold Chemistry: From Simple Salts to Complexes for Regioselective C−H Bond Functionalization
Authors: Praveen Chandrasekar , Dupeux Aurélien , Michelet Véronique 
Published: April 2021

AbstractGold coordinated to neutral phosphines (R3P), N‐heterocyclic carbenes (NHCs) or anionic ligands is catalytically active in functionalizing various C−H bonds with high selectivity. The sterics/electronic nature of the studied C−H bond, oxidation state of gold and stereoelectronic capacity of the coordinated auxiliary ligand are some of the associated selectivity factors in gold‐catalyzed C−H bond functionalization reactions. Hence, in this review a comprehensive update about the action of different types of gold catalysts, from simple to sophisticated ones, on C−H bond reactions and their regiochemical outcome is disclosed. This review also highlights the catalytic applications of Au(I)‐ and Au(III)‐species in creating new opportunities for the regio‐ and site‐selective activation of challenging C−H bonds. Finally, it also intends to stress the potential applications in selective C−H bond activation associated with a variety of heterocycles recently described in the literature.
Selective Production of Linear Aldehydes and Alcohols from Alkenes using Formic Acid as Syngas Surrogate
Authors: Chen Junjun , Hua Kaimin , Liu Xiaofang , Deng Yuchao , Wei Baiyin , Wang Hui , Sun Yuhan 
Published: April 2021

AbstractPerforming carbonylation without the use of carbon monoxide for high‐value‐added products is an attractive yet challenging topic in sustainable chemistry. Herein, effective methods for producing linear aldehydes or alcohols selectively with formic acid as both carbon monoxide and hydrogen source have been described. Linear‐selective hydroformylation of alkenes proceeds smoothly with up to 88 % yield and >30 regioselectivity in the presence of single Rh catalyst. Strikingly, introducing Ru into the system, the dual Rh/Ru catalysts accomplish efficient and regioselective hydroxymethylation in one pot. The present processes utilizing formic acid as syngas surrogate operate simply under mild condition, which opens a sustainable way for production of linear aldehydes and alcohols without the need for gas cylinders and autoclaves. As formic acid can be readily produced via CO2 hydrogenation, the protocols represent indirect approaches for chemical valorization of CO2.
Complementary switching enabled cascaded boost‐buck‐boost (BS‐BB) and buck‐boost‐buck (BB‐BU) converters
Authors: Naresh SVK , Peddapati Sankar 
Published: April 2021

SummaryIn this paper, two cascaded buck‐boost nature converters are developed; one converter is capable of producing high step‐up gain, and the other converter addresses high step‐down gain. In proposed converters, for a given voltage gain, two distinct duty ratios are possible due to their ability in handling complementary switching schemes. This feature is effective for voltage‐sensitive applications like LED systems. The operation principle, steady‐state analysis, and the design of the passive components for each switching scheme are presented for the proposed converters. Comparative analysis with competitive converters profound the merits of the proposed converters in terms of voltage gain and the continuous nature of the output. Experiments are conducted on both proposed converters for simultaneous and complementary switching schemes, and they validate the theoretical steady‐state performance.
Cytomorphometry and morphology analysis of human papillomavirus type 16 in liquid‐based cervical cytology samples
Authors: Safi Oz Zehra , Onak Kandemir Nilufer , Kokturk Furuzan , Ozdamar Sukru Oguz 
Published: April 2021

AbstractBackgroundHuman papillomavirus (HPV) is the main causal factor of cervical carcinoma. HPV 16 is one of the most prominent oncogenic types. We aimed to evaluate the cytomorphometric and morphological alterations caused by HPV 16 in liquid‐based cytology (LBC).MethodsThe Cobas 4800 HPV system was used for the detecting and typing HPV DNA in cervical specimens. In this study, 30 HPV 16 positive and 30 HPV 16 negative cervical samples were evaluated for micronuclei (MN), nonclassical cytologic abnormalities, and the nuclear‐to‐cytoplasmic ratio. Nuclear and cellular areas were evaluated using image analysis software and the nuclear‐to‐cytoplasm ratio was calculated. All analyses were performed blinded to the patients' HPV status. Statistical evaluation was carried out using the χ2 and Fisher test; P‐values < .05 were considered significant.ResultsThe frequencies of micronucleated cells and koilocytes were higher in the HPV 16 infected group (P < .05). Cells with perinuclear halo in control group were higher than the HPV 16 infected group (P < .05). The mean nuclear‐to‐cytoplasm ratio in HPV 16 patients was higher than the control value, but the difference was not statistically significant.ConclusionLBC can be used to detect morphological and morphometric changes. HPV 16 induces the formation of MN and koilocytosis. The evaluation of MN could provide additional information in monitoring genomic instability and of koilocytes could provide information about damage to the cytoskeleton filaments in HPV infection. Further studies are needed to investigate the effects of HPV‐18 and other high‐risk HPV types on the cell size and nucleus‐to‐cytoplasm ratio.
Mixing characteristics of a bubble mixing microfluidic chip for genomic DNA extraction based on magnetophoresis: CFD simulation and experiment
Authors: Sun Lin , K. Siddique Muhammad , Wang Lei , Li Songjing 
Published: April 2021

AbstractMixing a small amount of magnetic beads and regents with large volume samples evenly in microcavities of a microfluidic chip is always the key step for the application of microfluidic technology in the field of magnetophoresis analysis. This article proposes a microfluidic chip for DNA extraction by magnetophoresis, which relies on bubble rising to generate turbulence and microvortices of various sizes to mix magnetic beads with samples uniformly. The construction and working principle of the microfluidic chip are introduced. CFD simulations are conducted when magnetic beads and samples are irritated by the generation of gas bubbles with the variation of supply pressures. The whole mixing process in the microfluidic chip is observed through a high‐speed camera and a microfluidic system when the gas bubbles are generated continuously. The influence of supply pressure on the mixing characteristics of the microfluidic chip is investigated and discussed with both simulation and experiments. Compared with magnetic mixing, bubble mixing can avoid the magnetic beads gather phenomenon caused by magnetic forces and provide a rapid and high efficient solution to realize mixing small amount of regents in large volume samples in a certain order without complex moving structures and operations in a chip. Two applications of mixing with the proposed microfluidic chip are also carried out and discussed.
Association of genomic variants at PAX8 and PBX2 with cervical cancer risk
Authors: Ramachandran Dhanya , Wang Yingying , Schürmann Peter , Hülse Fabienne , Mao Qianqian , Jentschke Matthias , Böhmer Gerd , Strauß Hans‐Georg , Hirchenhain Christine , Schmidmayr Monika , Müller Florian , Runnebaum Ingo , Hein Alexander , Koch Martin , Ruebner Matthias , Beckmann Matthias W. , Fasching Peter A. , Luyten Alexander , Dürst Matthias , Hillemanns Peter , Dörk Thilo 
Published: April 2021

AbstractCervical malignancy is triggered by human papillomavirus infection but the risk for cervical cancer has a hereditary component. From a recent Genome Wide Association Study meta‐analysis, 2q14.1 (PAX8) and 6p21.32 (PBX2) have been proposed as novel cervical cancer susceptibility loci. We investigated the two main signals at these loci in an independent case‐control series of 2578 cases with cervical dysplasia or carcinoma and 1483 healthy females. We find significant associations for both variants, rs10175462 at PAX8 and rs2856437 at PBX2, with overall cervical disease (rs10175462: odds ratio [OR] 0.82, 95% confidence interval [CI] 0.74‐0.91, P = 2.4 × 10−4; rs2856437: OR 1.52, 95% CI 1.14‐2.02, P = .004). Both variants showed evidence of association with invasive squamous cervical cancer (rs10175462: OR 0.80, 95% CI 0.68‐0.94, P = .006; rs2856437: OR 1.56, 95% CI 1.03‐2.36, P = .036) and with high‐grade dysplasia (rs10175462: OR 0.79, 95%CI 0.70‐0.90, P = 1.9 × 10−4; rs2856437: OR 1.58, 95% CI 1.15‐2.17, P = .005). A combined analysis of high‐grade dysplasia and invasive cervical cancer also showed significant associations for both variants (rs10175462: OR 0.81, 95% CI 0.73‐0.91, P = 2.4 × 10−4; rs2856437: OR 1.57, 95% CI 1.18‐2.10, P = .002). No association was detected for rs2856437 with low‐grade dysplasia, while rs10175462 showed weak evidence of association (P = .05). RNA analyses in cervical samples revealed that PAX8 transcripts were upregulated in HPV‐positive lesions (P = .008) but this was not observed in the presence of the protective minor allele of rs10175462. The rs10175462 genotype also correlated with reduced levels of the lncRNA PAX8‐AS1 (P < .001). Taken together, our results extend the evidence for a link between genomic risk variants at the HLA region (PBX2) with cervical disease and support PAX8 as the first consistent non‐HLA cervical cancer susceptibility locus.
Negative‐pressure irrigation improves water and fertilizer use efficiencies and fruit yield of greenhouse tomato on the North China Plain*
Authors: Li Yinkun , Xue Xuzhang , Xu Fan , Guo Wenzhong , Duan Minjie , Lin Sen , Li Youli , Wang Zhan 
Published: April 2021

AbstractWater and fertilizer supply are the main factors limiting greenhouse vegetable production on the North China Plain. This study tested the hypothesis that negative‐pressure irrigation is advantageous for reducing water and fertilizer application compared with drip irrigation in a greenhouse. Three treatments (drip irrigation + optimal fertilizer [DOF], drip irrigation + Yamazaki tomato nutrient solution [DNS], and negative‐pressure irrigation + Yamazaki tomato nutrient solution [NNS]) were applied in a greenhouse tomato double‐cropping system conducted in consecutive spring–summer and autumn–winter seasons. Soil moisture content, nitrate‐nitrogen (N) concentration, fruit yield, total N uptake (Nu), irrigation water productivity, and partial factor productivity of applied fertilizer were analysed. The seasonal variation of soil moisture and nitrate‐N contents in the 0–20‐cm soil layer for NNS treatment was stable. Nitrate‐N accumulated after the final harvest in the autumn–winter season of NNS treatment was significantly less than under DOF and DNS. Despite lower water and nutrient inputs, NNS showed higher Nu and fruit yield than DOF and DNS. These results demonstrated that negative‐pressure irrigation can reduce irrigation water and nutrient inputs and nitrate‐N accumulation in the soil, and significantly improve water and fertilizer use efficiency in greenhouse‐grown tomato compared with those under drip irrigation.
Extracellular vesicles from monocyte/platelet aggregates modulate human atherosclerotic plaque reactivity
Authors: Oggero Silvia , de Gaetano Monica , Marcone Simone , Fitzsimons Stephen , Pinto Andreia L. , Ikramova Dinara , Barry Mary , Burke David , Montero‐Melendez Trinidad , Cooper Dianne , Burgoyne Thomas , Belton Orina , Norling Lucy V. , Brennan Eoin P. , Godson Catherine , Perretti Mauro 
Published: April 2021

AbstractExtracellular vesicles (EVs) are emerging as key players in different stages of atherosclerosis. Here we provide evidence that EVs released by mixed aggregates of monocytes and platelets in response to TNF‐α display pro‐inflammatory actions on endothelial cells and atherosclerotic plaques. Tempering platelet activation with Iloprost, Aspirin or a P2Y12 inhibitor impacted quantity and phenotype of EV produced. Proteomics of EVs from cells activated with TNF‐α alone or in the presence of Iloprost revealed a distinct composition, with interesting hits like annexin‐A1 and gelsolin. When added to human atherosclerotic plaque explants, EVs from TNF‐α stimulated monocytes augmented release of cytokines. In contrast, EVs generated by TNF‐α together with Iloprost produced minimal plaque activation. Notably, patients with coronary artery disease that required percutaneous coronary intervention had elevated plasma numbers of monocyte, platelet as well as double positive EV subsets. In conclusion, EVs released following monocyte/platelet activation may play a potential role in the development and progression of atherosclerosis. Whereas attenuating platelet activation modifies EV composition released from monocyte/platelet aggregates, curbing their pro‐inflammatory actions may offer therapeutic avenues for the treatment of atherosclerosis.
Impact of sarcopenia on recurrent biliary obstruction after insertion of self‐expandable metallic stent in patients with malignant biliary obstruction
Authors: Koya Yudai , Shibata Michihiko , Oe Shinji , Honma Yuichi , Nebuya Satoru , Miyagawa Koichiro , Yoshikawa Ichiro , Harada Masaru 
Published: April 2021

AbstractBackground/PurposeRecurrent biliary obstruction (RBO) after self‐expandable metallic stent (SEMS) insertion is a big problem in patients with unresectable malignant biliary obstruction (MBO). Sarcopenia is associated with poor prognosis in patients with malignancies. The purpose of this study is to clarify the relationship between RBO and sarcopenia.MethodsForty‐six patients with normal psoas muscle mass index (PMI) and 55 with low PMI were enrolled, based on PMI cut‐off values. We analyzed the cumulative incidences and predictors of RBO, considering death without RBO to be a competing risk.ResultsIn the Kaplan‐Meier analysis, the 60‐, 180‐, and 360‐day cumulative incidence rates of RBO were 0.0%, 12.2%, and 22.0% in the normal PMI group, as compared to 4.0%, 31.1%, and 55.0% in the low PMI group, respectively (log‐rank P = .003). In competing risk analysis, the incidences were 2.9%, 2.9%, and 7.1% in the normal PMI group, as compared to 13.7%, 34.8%, and 51.7% in the low PMI group, respectively (P < .001). In multivariate Cox regression and Fine‐Gray's analyses, hazard ratios of low PMI for RBO were 4.593 (95% confidence interval 1.673‐12.61, P = .003) and 4.980 (2.045‐12.13, P < .001), respectively.ConclusionsSarcopenia in MBO was an independent risk factor for RBO.
Cation Template‐Assisted RAFT Cyclopolymerization of Hexa(Ethylene Glycol) Di(meth)acrylates to Thermoresponsive Pseudo‐Crown Ether Polymers
Authors: Kimura Yoshihiko , Terashima Takaya 
Published: April 2021

AbstractCation template‐assisted reversible addition fragmentation/chain transfer (RAFT) cyclopolymerization of hexa(ethylene glycol) diacrylate (PEG6DA) or hexa(ethylene glycol) dimethacrylate (PEG6DMA) is developed as a versatile system to produce large in‐chain ring cyclopolymers, thermoresponsive pseudo‐crown ether polymers. For an efficient synthesis, potassium hexafluorophosphate (KPF6) is employed as a cation template; PEG6DA as well as PEG6DMA recognizes the potassium cation with the hexa(ethylene glycol) spacer to dynamically form a pseudo‐cyclic divinyl monomer. Those monomers interacting with the potassium cations are efficiently polymerized with RAFT agents and radical initiators into cyclopolymers comprising 24‐membered hexa(ethylene glycol) rings. The cation template‐assisted RAFT cyclopolymerization is also effective for the synthesis of amphiphilic random cyclocopolymers bearing hydrophilic hexa(ethylene glycol) rings and hydrophobic butyl groups. Cyclopolymers of PEG6DA and PEG6DMA further show thermoresponsive solubility in water. The cloud point temperature of cyclopoly(PEG6DA)s is higher than that of a cyclopoly(PEG6DMA).
An Advanced Material with Synergistic Viscoelasticity Enhancement of Hydrophobically Associated Water‐Soluble Polymer and Surfactant
Authors: Wang Tongyu , Kang Wanli , Yang Hongbin , Li Zhe , Zhu Tongyu , Sarsenbekuly Bauyrzhan , Gabdullin Maratbek 
Published: April 2021

AbstractIn order to prepare materials with controllable properties, changeable microstructure, and high viscoelasticity solution with low polymer and surfactant concentration, a composite is constituted by adding surfactant (sodium dodecyl sulfate, SDS) to hydrophobically associated water‐soluble polymer (abbreviated as PAAC) solution. The viscoelasticity, aggregate microstructure, and interaction mechanism of the composite are investigated by rheometery, Cryo‐transmission electron microscopy (Cryo‐TEM), and fluorescence spectrum. The results show that when the mass ratio of polymer to surfactant is 15:1, the viscosity of the composite reaches the maximum. The viscosity of the composite system increases hundredfold. The viscosity plateau under dynamic shear is generated. The composite has the properties of high viscoelasticity, strong shear thinning behavior, and good salt tolerance, and temperature resistance. The maximum viscosity of the composite is shown at the salinity of 20000 mg L−1. In addition, there is no phase separation in the composite with the increase of polymer and surfactant concentration, which indicates the good stability of the system. It is proposed a method to obtain a high viscoelasticity solution by adding surfactants without wormlike micelles to a hydrophobically associated water‐soluble polymer solution.
Porous Electroactive and Biodegradable Polyurethane Membrane through Self‐Doping Organogel
Authors: Fang Wei , Sun Fuhua , Tang Jiajing , Zhao Qing , Chen Jie , Lei Xiaoyu , Zhang Jinzheng , Zhang Yinglong , Zuo Yi , Li Jidong , Li Yubao 
Published: April 2021

AbstractIn order to improve the processability of conductive polyurethane (CPU) containing aniline oligomers, a new CPU containing aniline trimer (AT) and l‐lysine (PUAT) are designed and synthesized. Further, the 3D porous PUAT membranes have been prepared by a simple gel cooperated with freeze‐drying method. Chemical testings and conductive properties testify a self‐ doping model of PUAT based on the rich electronic l‐lysine and electroaffinity AT moities. The self‐doping behavior further endows the PUAT copolymers specific characteristics such as high electrical conductivity and the formation of the polaron lattice like‐structure in good solvent dimethyl sulfoxide. The combination of organogel and freeze‐drying could prevent the collapse of pore structure when the copolymers are molded as membranes. The synergistic effect of l‐lysine and AT components has a strong influence on the dissolution, degradation, thermal stability, and mechanical properties of PUAT. The excellent properties of PUAT would broad the application of conductive polymers in biomedicine field.
Quadratic relation for mass density calibration in human body using dual‐energy CT data
Authors: Saito Masatoshi 
Published: April 2021

PurposeTo derive the mass density (ρ) from dual‐energy computed tomography (DECT) data by calibrating electron density (ρe) and effective atomic numbers (Zeff) of human tissues.MethodsWe propose the DEEDZ‐MD method, in which a single polynomial parameterization covers the entire human‐tissue range to establish an empirical quadratic relation between the atomic number‐to‐mass ratio and Zeff. Then, we numerically evaluate the DEEDZ‐MD method in reference human tissues listed in the ICRP Publication 110 and ICRU Report 46. The tissues are considered to have unknown ρ values. The attenuation coefficients of these tissues are calculated using the XCOM Photon Cross Sections Database. The DEEDZ‐MD method is also applied to experimental DECT data acquired from a tissue characterization phantom and an anthropomorphic phantom at 90 kV and 150 kV/Sn.ResultsThe numerical analysis of the DEEDZ‐MD method reveals a single quadratic relation between the atomic number‐to‐mass ratio and Zeff in a wide range of human tissues. The simulated ρ values are in excellent agreement with the reference values over ρ values from 0.260 (lung) to 3.225 (hydroxyapatite). The relative deviations from the reference ρ remain within ±0.6% for all the reference human tissues, except for the eye lens (approximate deviation of −1.0%). The overall root‐mean‐square error is 0.24%. The application of the DEEDZ‐MD method to experimental dual‐energy CT data confirms this agreement within experimental accuracy, indicating the practical feasibility of the method. The DEEDZ‐MD method enables the generation of ρ images with less image noise than the existing DECT‐based conversion of ρ from ρe and with fewer beam‐hardening artifacts than conventional single‐energy CT images.ConclusionsThe DEEDZ‐MD method can facilitate the generation of ρ images from dual‐energy CT data without relying on the nontrivial segmentation of different tissues.
Deep cross‐modality (MR‐CT) educed distillation learning for cone beam CT lung tumor segmentation
Authors: Jiang Jue , Riyahi Alam Sadegh , Chen Ishita , Zhang Perry , Rimner Andreas , Deasy Joseph O. , Veeraraghavan Harini 
Published: April 2021

PurposeDespite the widespread availability of in‐treatment room cone beam computed tomography (CBCT) imaging, due to the lack of reliable segmentation methods, CBCT is only used for gross set up corrections in lung radiotherapies. Accurate and reliable auto‐segmentation tools could potentiate volumetric response assessment and geometry‐guided adaptive radiation therapies. Therefore, we developed a new deep learning CBCT lung tumor segmentation method.MethodsThe key idea of our approach called cross‐modality educed distillation (CMEDL) is to use magnetic resonance imaging (MRI) to guide a CBCT segmentation network training to extract more informative features during training. We accomplish this by training an end‐to‐end network comprised of unpaired domain adaptation (UDA) and cross‐domain segmentation distillation networks (SDNs) using unpaired CBCT and MRI datasets. UDA approach uses CBCT and MRI that are not aligned and may arise from different sets of patients. The UDA network synthesizes pseudo MRI from CBCT images. The SDN consists of teacher MRI and student CBCT segmentation networks. Feature distillation regularizes the student network to extract CBCT features that match the statistical distribution of MRI features extracted by the teacher network and obtain better differentiation of tumor from background. The UDA network was implemented with a cycleGAN improved with contextual losses separately on Unet and dense fully convolutional segmentation networks (DenseFCN). Performance comparisons were done against CBCT only using 2D and 3D networks. We also compared against an alternative framework that used UDA with MR segmentation network, whereby segmentation was done on the synthesized pseudo MRI representation. All networks were trained with 216 weekly CBCTs and 82 T2‐weighted turbo spin echo MRI acquired from different patient cohorts. Validation was done on 20 weekly CBCTs from patients not used in training. Independent testing was done on 38 weekly CBCTs from patients not used in training or validation. Segmentation accuracy was measured using surface Dice similarity coefficient (SDSC) and Hausdroff distance at 95th percentile (HD95) metrics.ResultsThe CMEDL approach significantly improved (p < 0.001) the accuracy of both Unet (SDSC of 0.83 ± 0.08; HD95 of 7.69 ± 7.86 mm) and DenseFCN (SDSC of 0.75 ± 0.13; HD95 of 11.42 ± 9.87 mm) over CBCT only 2DUnet (SDSC of 0.69 ± 0.11; HD95 of 21.70 ± 16.34 mm), 3D Unet (SDSC of 0.72 ± 0.20; HD95 15.01 ± 12.98 mm), and DenseFCN (SDSC of 0.66 ± 0.15; HD95 of 22.15 ± 17.19 mm) networks. The alternate framework using UDA with the MRI network was also more accurate than the CBCT only methods but less accurate the CMEDL approach.ConclusionsOur results demonstrate feasibility of the introduced CMEDL approach to produce reasonably accurate lung cancer segmentation from CBCT images. Further validation on larger datasets is necessary for clinical translation.