bluuebunny/crossref_metadata_2025 huggingface dataset:
Intestinal metabolism of Polygonum cuspidatum in vitro and in vivo
Authors: Fu Jinfeng , Wu Songyan , Wang Min , Tian Yuan , Zhang Zunjian , Song Rui
Published: January 2018

Rhizoma et Radix Polygoni Cuspidati (RRPC) is commonly prescribed for the treatment of amenorrhea, arthralgia, jaundice and abscess in traditional Chinese medicine. Previous pharmacological studies have indicated that polyphenols are the main pharmacological active ingredients in RRPC. Meanwhile, the poor bioavailability of polyphenols in RRPC implies that those components are probably metabolized by intestinal bacteria before absorption. However, there is rather limited information about RRPC''s metabolites produced by intestinal bacteria and the intestinal absorbed constituents. In the present study, the metabolites were characterized after the aqueous extract of RRPC was incubated with the crude enzyme of human intestinal bacteria in vitro. The metabolic characteristics of glycosides in RRPC were figured out by comparing the metabolic profiles of emodin‐8‐O‐β‐d‐glucopyranoside and polydatin between aqueous extract of RRPC and equivalent amounts of these two glycosides. The transitional constituents absorbed into blood were investigated in rats via intraduodental administration and portal vein intubation. A total of 38 prototype components and 43 metabolites were detected and characterized in vivo. The overall results demonstrated that the intestinal bacteria played an important role in the metabolism of RRPC, and the main metabolic pathways were hydrolysis in vitro, glucuronidation and sulfation in vivo.
Efficient Catalytic Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Furandicarboxylic Acid by Magnetic Laccase Catalyst
Authors: Wang Ke‐Feng , Liu Chun‐lei , Sui Kun‐yan , Guo Chen , Liu Chun‐Zhao
Published: January 2018

2,5‐Furandicarboxylic acid (FDCA) is a bio‐based platform chemical for the production of polyethylene furanoate (PEF) and other valuable furanic chemicals. A magnetic laccase catalyst with (2,2,6,6‐tetramethyl‐piperidin‐1‐yl)oxyl (TEMPO) as the mediator has the remarkable capability of oxidizing 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA). Under optimal reaction conditions, a quantitative yield (90.2 %) of FDCA with complete HMF conversion was obtained after 96 h of reaction. More importantly, the magnetic laccase catalyst exhibited good recyclability and stability, maintaining 84.8 % of its original activity following six reuse cycles. This is the first report on the efficient catalytic oxidation of HMF to FDCA by using an immobilized enzyme catalyst.
Core/Shell NiFe Nanoalloy with a Discrete N‐doped Graphitic Carbon Cover for Enhanced Water Oxidation
Authors: Deng Chen , Wu Kuang‐Hsu , Scott Jason , Zhu Shenmin , Amal Rose , Wang Da‐Wei
Published: January 2018

Developing highly efficient and earth‐abundant electrocatalysts for the oxygen evolution reaction (OER) is critical in overall water splitting technology. Among all transition‐metal‐based materials, NiFe‐based electrocatalysts have been regarded as the most promising substitute to commercial noble metals in alkaline conditions. To overcome their leaching problem and improve intrinsic stability without compromising activity, we report a NiFe alloy covered with a discrete N‐doped graphitic shell for the OER. The alloy core@discrete graphitic shell structure exhibits enhanced OER activity and stability with a low onset potential of 1.48 V, reduced overpotential of 320 mV@10 mA cm−1, and small Tafel slope value of 41 mV dec−1, which is superior to Ir/C. It is believed that the nitrogen doping, a discrete graphitic shell, and a mesoporous structure work in harmony to enhance the OER performance.
Metal‐Organic‐Framework‐Derived Co Nanoparticles Deposited on N‐Doped Bimodal Mesoporous Carbon Nanorods as Efficient Bifunctional Catalysts for Rechargeable Zinc−Air Batteries
Authors: Han Huijuan , Chao Shujun , Bai Zhengyu , Wang Xiaobing , Yang Xiaoli , Qiao Jinli , Chen Zhongwei , Yang Lin
Published: January 2018

Electrically rechargeable zinc−air batteries (ZnABs) have received increasing attention as promising energy storage devices, owing to their high theoretical energy density and environmental friendliness. However, it remains a great challenge to develop highly efficient bifunctional catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, we design and prepare a highly active bifunctional catalyst for ZnABs by using a cobalt metal‐organic framework (Co‐MOF) as the precursor. The catalyst has a desirable nanostructure composed of cobalt nanoparticles deposited on N‐doped bimodal mesoporous carbon nanorods (Co@N‐CNR). This hybrid structure exhibits a higher catalytic activity (a maximum power density of 63 mW cm−2) and cycling stability compared to commercial Pt/C+Ir/C integrated in ZnABs. The high catalytic performance could be attributed to the unique nanostructure composed of Co@N‐CNR, which incorporates the advantageous features of cobalt nanoparticles, mesoporous materials, and N‐CNR towards OER and ORR. The reported advancement provides a new and efficient strategy for the development of rechargeable ZnABs.
Heterobimetallic Complexes for Theranostic Applications
Authors: Fernández‐Moreira Vanesa , Gimeno M. Concepción
Published: January 2018

The design of more efficient anticancer drugs requires a deeper understanding of their biodistribution and mechanism of action. Cell imaging agents could help to gain insight into biological processes and, consequently, the best strategy for attaining suitable scaffolds in which both biological and imaging properties are maximized. A new concept arises in this field that is the combination of two metal fragments as collaborative partners to provide the precise emissive properties to visualize the cell as well as the optimum cytotoxic activity to build more potent and selective chemotherapeutic agents.
Identification of the Minimal Glycotope of Streptococcus pneumoniae 7F Capsular Polysaccharide using Synthetic Oligosaccharides
Authors: Ménová Petra , Sella Mauro , Sellrie Katrin , Pereira Claney L. , Seeberger Peter H.
Published: January 2018

Streptococcus pneumoniae causes life‐threatening diseases including meningitis, pneumonia and sepsis. Existing glycoconjugate vaccines based on purified capsular polysaccharides are widely used and help to prevent millions of deaths every year. Herein, the total syntheses of oligosaccharides resembling portions of the S. pneumoniae serotype 7F (ST7F) capsular polysaccharide repeating unit are reported. To define minimal glycan epitopes, glycan microarrays containing the synthetic oligosaccharides were used to screen human reference serum and revealed that both side chains of the ST7F play a key role in antigen recognition. The identification of protective minimal epitopes is vital to design efficient semi‐ and fully‐synthetic glycoconjugate vaccines.
Flexible all‐to‐all data redistribution methods for grid‐based particle codes
Authors: Hofmann Michael , Rünger Gudula
Published: January 2018

The article proposes a fine‐grained all‐to‐all communication operation that can implement flexible data redistribution patterns of irregular applications, such as particle codes. The flexibility is achieved by user‐defined distribution functions, which are used to specify how data elements are to be redistributed among parallel processes on a distributed memory platform. The usage is illustrated for a particle data redistribution step of a grid‐based particle code in which the destination processes for particles are calculated from the particle positions by a specific distribution function. Additionally, the fine‐grained all‐to‐all communication operation proposed allows the duplication and modification of data elements during the data redistribution. This functionality is useful for automatically creating ghost particles for the domain decomposition of the particle code during the particle data redistribution step. The interface of the fine‐grained all‐to‐all communication operation is described and several algorithms for implementing the operation on top of existing MPI operations are presented. Performance results on an IBM Blue Gene/Q platform demonstrate the performance of the communication operation proposed with synthetic benchmark data as well as with a parallel particle code.
Reaction Mechanism for Direct Cyclization of Linear C5, C6, and C7 Alkenes over H‐ITQ‐13 Zeolite Investigated Using Density Functional Theory
Authors: Ma Hong , Chen Yanyan , Wei Zhihong , Wang Sen , Qin Zhangfeng , Dong Mei , Li Junfen , Wang Jianguo , Fan Weibin
Published: January 2018

Although dienes or trienes have been shown to be possible precursors for cyclization, direct cyclization of alkenes or alkoxides has not been systematically studied yet. Thus, the reaction mechanism of cyclization of linear alkenes over H‐ITQ‐13 was investigated here by density functional theory considering dispersive interactions (DFT‐D). The similar free energy of different linear alkoxides of the same carbon number suggests that they can co‐exist in the H‐ITQ‐13 intersection at 673.15 K during the methanol to olefins (MTO) process. The formation of linear alkenes by olefins methylation with methoxyl groups (ZOCH3), trimethyloxonium ions (TMO+), and methanol are kinetically more favorable than by dimerization of olefins. Linear alkoxides or alkenes prefer direct cyclization to cycloalkanes rather than hydride transfer to diene. This study provides new insight into the alkene cyclization and aromatization mechanisms in MTO process.
Preparation and Thermoelectric Properties of Zn‐Doped Sn‐Based Type‐VIII Single‐Crystalline Clathrate via a Grey Sn‐Flux Method
Authors: Shen Lanxian , Li Decong , Deng Shuping , Tang Yu , Chen Zhong , Liu Zuming , Yang Peizhi , Deng Shukang
Published: January 2018

A single‐crystalline samples of Zn‐substituted type‐VIII clathrate Ba8Ga16Sn30 with n‐type carriers by α‐Sn flux method according to the formula Ba8Ga16ZnxSn30 (x = 0, 0.5, 1, and 1.5) is grown. It is found that as the amount of Zn increases from 0.025 to 0.155, the content of Ga decreases from 15.18 to 14.72, indicating Zn atoms preferentially replacing Ga. The carrier concentrations of obtained samples vary from 3.55 × 1019 to 5.53 × 1019 cm−3 as carrier mobility changes from 14.7 to 20.9 cm2 · V−1 · s−1 at room temperature. Meanwhile, the endothermic peak temperature for all samples is approximately 519 °C, which is slightly lower than that of the previous experimental reported. For all samples, their effective mass m*/m0 are lower than that prepared by β‐Sn, indicating that the band structure near the conduction band minima is affected. As a result, the sample with x = 1.5 obtains the higher power factor with the maximum value of 1.07 × 10−3 W m−1 K−2 at 568 K and the largest ZT value of 0.63 at 537 K.
Real‐Time Skin Lactic Acid Monitoring System for Assessment of Training Intensity
Authors: ENOMOTO KEIGO , SHIMIZU RYOSUKE , KUDO HIROYUKI
Published: January 2018

A microfluidic system using electrochemical biosensor for continuous lactic acid (LA) monitoring at the skin's surface was fabricated and tested. The system consists of a micro flow‐cell for sampling LA at the skin's surface and a microfluidic LA biosensor based on a redox reaction of osmium wired horseradish peroxidase. Our system measures excreted LA by dissolving whole secretion in phosphate buffered saline (PBS), which was supplied into the microchannel as carrier flow. The measurement system was utilized in the real‐time monitoring of LA secretion during stationary bike exercises. Exercise intensities were regulated by heart rates (HRs) and the sampling device was attached on the right upper arm of the volunteer. During the exercise, PBS was circulated into the measurement system. As a result, change of LA levels correlated with the volunteer's physiological status was confirmed. Secretion of LA was estimated to be 4.50 μg/cm2/min when the intensity of exercise was high (HR: 160 bpm) and the signal decreased to the initial level after the exercise. This indicates that our system is suitable for not only the assessment of exercise intensity, but also useful in evaluation of metabolic activity.
The Nature of the Technetium Species Formed During the Oxidation of Technetium Dioxide with Oxygen and Water
Authors: Childs Bradley C. , Lawler Keith V. , Braband Henrik , Mast Daniel S. , Bigler Laurent , Stalder Urs , Peterson Derek R. , Jansen Alek , Forster Paul M. , Czerwinski Kenneth R. , Alberto Roger , Sattelberger Alfred P. , Poineau Frederic
Published: January 2018

The oxidation of TcO2 with O2 in the presence of H2O at 250 °C was investigated; Tc2O7 and a red product were observed after the reaction. UV/Visible spectroscopy and a cerium titration on the “red” product are consistent with the presence of a reduced Tc species. It is proposed that the “red” product was formed by the hydrolysis of Tc2O7 to HTcO4 followed by the reduction of HTcO4. The reaction products of TcO2 with O2/H2O at 250 °C were also studied by mass spectrometry. The main dinuclear species were Tc2O7 and Tc2O5, while the main mononuclear species were TcO3 and HTcO4. The compound HTcO4 and associated hydrates were simulated to identify candidate structures for the “red” product; however, neither the acid nor any related hydrates exhibited the UV/Visible signature of the “red” product.
Development of Efficient Copper‐Based MOF‐Derived Catalysts for the Reduction of Aromatic Nitro Compounds
Authors: Karahan Özlem , Biçer Emre , Taşdemir Adnan , Yürüm Alp , Gürsel Selmiye Alkan
Published: January 2018

Two copper‐based Cu3(btc)2 and Cu(Im)2 metal–organic frameworks are synthesized and annealed to form nanoporous Cu/Cu2O@C and Cu@N‐C nanoparticles for utilization as catalysts in the reduction reaction of aromatic nitro compounds to aromatic amines. All synthesized MOF compounds and MOF‐derived nanoparticles are characterized using XRD, Raman spectroscopy, TGA, SEM‐EDX, and XPS methods. Also, the pore‐size distribution and surface area of the MOF‐derived Cu/Cu2O@C and Cu@N‐C nanoparticles are characterized by the BJH and BET methods. After characterization, the catalysts Cu/Cu2O@C and Cu@N‐C are catalytically tested for the reduction reactions of various aromatic nitro compounds chemically by monitoring with a UV/Vis spectrometer. Both catalysts exhibit remarkable results compared with those in the literature. Also, the Cu/Cu2O@C catalyst shows better results than the Cu@N‐C catalyst.
Tetrahydrosalen Uranyl(VI) Complexes: Crystal Structures and Solution Binding Study
Authors: Zhao Xiao , Zhang Di , Yu Ren , Chen Shusen , Zhao Dahui
Published: January 2018

A pair of uranyl complexes incorporating tetrahydrosalen and N,N‐dimethyltetrahydrosalen ligands are synthesized and studied. These new ligands, with saturated secondary and tertiary amines, exhibit higher chemostability than the prototype Schiff base (salen) structure, especially under acidic conditions. As shown by X‐ray diffraction crystallography, the coordination geometry of uranium in these new complexes is a distorted pentagonal bipyramid. Interestingly, UO2([H4]‐salen), comprising the tetrahydrosalen ligand, forms a dimeric structure in the crystals, with two subunits held together by sharing one of the two phenoxy oxygen atoms from each subunit, whereas UO2([H2Me2]‐salen) with the N,N‐dimethyltetrahydrosalen ligand is in the monomer state, with a solvent molecule coordinated to uranium to complete the penta‐coordination configuration. Moreover, as revealed by UV/Vis spectroscopy using the colorimetry method, these hydrogenated salen ligands exhibit comparable, or even higher, binding affinities toward uranyl than the prototype Schiff base salen ligand in weakly basic solution.
State‐of‐Power Estimation of Li‐Ion Batteries Considering the Battery Surface Temperature
Authors: Liu Xintian , He Yao , Zeng Guojian , Zhang Jiangfeng , Zheng Xinxin
Published: January 2018

The state‐of‐power (SOP) of a Li‐ion battery (LIB) is an important evaluation index for safety control and energy recovery in electric vehicles. Major state estimation methods are only applicable to fixed room temperature at 20 °C, although the battery capacity and resistance vary dramatically with a change in battery surface temperature in the working process of the battery. This causes significant errors in state estimation if only room temperature is assumed. The inaccurate state may cause further excessive current at high or low temperatures to affect safety and life cycle of the battery. Therefore, a novel state estimation method applicable to various battery surface temperatures is developed here. This method uses capacity–temperature and resistance–temperature relationships from experimental data to more accurately predict battery capacity and resistance over the full temperature range. It then applies the extended Kalman filter (EKF) technique to estimate the state‐of‐charge, and a method of constrained multi‐parameter algorithm (CMPA) to estimate the SOP of LIBs. Simulation and experimental results show that the proposed method can obtain accurate SOP results at different temperatures.
Modeling spatially correlated spectral accelerations at multiple periods using principal component analysis and geostatistics
Authors: Markhvida Maryia , Ceferino Luis , Baker Jack W.
Published: January 2018

Regional seismic risk assessments and quantification of portfolio losses often require simulation of spatially distributed ground motions at multiple intensity measures. For a given earthquake, distributed ground motions are characterized by spatial correlation and correlation between different intensity measures, known as cross‐correlation. This study proposes a new spatial cross‐correlation model for within‐event spectral acceleration residuals that uses a combination of principal component analysis (PCA) and geostatistics. Records from 45 earthquakes are used to investigate earthquake‐to‐earthquake trends in application of PCA to spectral acceleration residuals. Based on the findings, PCA is used to determine coefficients that linearly transform cross‐correlated residuals to independent principal components. Nested semivariogram models are then fit to empirical semivariograms to quantify the spatial correlation of principal components. The resultant PCA spatial cross‐correlation model is shown to be accurate and computationally efficient. A step‐by‐step procedure and an example are presented to illustrate the use of the predictive model for rapid simulation of spatially cross‐correlated spectral accelerations at multiple periods.
Anxiolytic‐like effects of essential oil from Thymus vulgaris was increased during stress
Authors: Satou Tadaaki , Hayakawa Mako , Goto Yumi , Masuo Yoshinori , Koike Kazuo
Published: January 2018

There is known to be a close relationship among anxiety, fatigue and stress. Here, we studied the anxiolytic‐like effects of essential oil from Thymus vulgaris (EOT), while focusing on the relationship with stress. Male ICR mice inhaled (i.h.) EOT for 90 min. Mice were placed under three different conditions; isolated, intraperitoneal (i.p.) administration of saline or polyinosinic‐polycytidylic acid (poly I:C). EOT did not show any significant anxiolytic‐like effects in isolated mice. On the other hand, in brain fatigue model mice by poly I:C, EOT showed significant anxiolytic‐like effects. EOT increased the absolute value in the elevated plus maze (EPM) tests in the brain fatigue model mice, while linalool and terpinen‐4‐ol in the brain with poly I:C were elevated when compared with isolated mice. Augmented concentrations of these components in the brain were also observed in mice with saline, i.p. These results suggest that the amount of volatile compounds transferred to the brain increased due to stress or inflammation. In the future, further investigation concerning the relationship between the blood brain barrier (BBB) and respiration is required.
New Insights into the Application of Lithium‐Ion Battery Materials: Selective Extraction of Lithium from Brines via a Rocking‐Chair Lithium‐Ion Battery System
Authors: He Lihua , Xu Wenhua , Song Yunfeng , Luo Yunze , Liu Xuheng , Zhao Zhongwei
Published: January 2018

Lithium extraction from high Mg/Li ratio brine is a key technical problem in the world. Based on the principle of rocking‐chair lithium‐ion batteries, cathode material LiFePO4 is applied to extract lithium from brine, and a novel lithium‐ion battery system of LiFePO4 | NaCl solution | anion‐exchange membrane | brine | FePO4 is constructed. In this method, Li+ is selectively absorbed from the brine by FePO4 (Li+ + e + FePO4 = LiFePO4); meanwhile, Li+ is desorbed from LiFePO4 (LiFePO4 − e = Li+ + FePO4) and enriched efficiently. To treat a raw brine solution, the Mg/Li ratio decreases from the initial 134.4 in the brine to 1.2 in the obtained anolyte and 83% lithium is extracted. For the treatment of an old brine solution, the Mg/Li ratio decreases from the initial 48.4 in the brine to 0.5 and the concentration of lithium in the anolyte is accumulated about six times (from the initial 0.51 g L−1 in the brine to 3.2 g L−1 in the anolyte), with the absorption capacity of about 25 mg (Li) g (LiFePO4)−1. Additionally, it displays a great perspective on the application in light of its high selectively, good cycling performance, effective lithium enrichment, environmental friendliness, low cost, and avoidance of poisonous organic reagents and harmful acid or oxidant.
Circular RNA hsa_circ_0000567 can be used as a promising diagnostic biomarker for human colorectal cancer
Authors: Wang Jianjun , Li Xiaomin , Lu Linming , He Lei , Hu Haoran , Xu Zengxiang
Published: January 2018

Background

Recent studies have revealed that circular RNAs are involved in the biological process of some kinds of human cancers. However, little is known about their diagnostic values and functions in colorectal cancer (CRC).

Methods

The expression levels of hsa_circ_0000567 in 102 paired CRC tissues and adjacent noncancerous tissues, 5 CRC cell lines, and a normal colorectal epithelial cell line were detected by quantitative real‐time polymerase chain reaction (qRT‐PCR). The correlations between hsa_circ_0000567 expression levels and the clinicopathological factors of patients with CRC were analyzed. Furthermore, the loss‐of‐function assay was performed to investigate the functions of hsa_circ_0000567 in vitro. Finally, a receiver operating characteristic (ROC) curve was established to evaluate the diagnostic value of hsa_circ_0000567.

Results

Hsa_circ_0000567 expression was significantly downregulated in CRC tissues and CRC cell lines. In addition, the decreased hsa_circ_0000567 expression in CRC was negatively correlated with tumor size (P = .011), lymph metastasis (P = .003), distal metastasis (P < .0001), and tumor–node–metastasis (TNM) stage (P = .003) in CRC. Moreover, knockdown of hsa_circ_0000567 promoted CRC cells proliferation and migration in vitro. Importantly, the area under the ROC curve (AUC) was 0.8653, which indicates hsa_circ_0000567 can serve as a diagnostic biomarker.

Conclusion

Hsa_circ_0000567 may be a novel suppressor and a potential diagnosis biomarker in CRC.
Determination of vitamins K1, MK‐4, and MK‐7 in human serum of postmenopausal women by HPLC with fluorescence detection
Authors: Klapkova Eva , Cepova Jana , Dunovska Katerina , Prusa Richard
Published: January 2018

Background

New high‐performance liquid chromatography (HPLC) method was developed for the determination of vitamin K1 and two forms of vitamin K2 (MK‐4 and MK‐7) in human serum, and the levels of vitamin K were determined in 350 samples of postmenopausal women.

Methods

Vitamin K was determined by HPLC with fluorescence detection after postcolumn zinc reduction. The detection was performed at 246 nm (excitation) and 430 nm (emission). The internal standard and 2 mL of ethanol were added to 500 μL of serum. The mixture was extracted with 4 mL of hexane, and solid phase extraction was then used.

Results

The HLPC method was fully validated. The intra‐ and interday accuracy and precision were evaluated on two QC samples by multiple analysis, and CV were less than 10%. The limit of quantification for MK‐4 was found at 0.04 ng/mL, for K1 0.03 ng/mL, and for MK‐7 0.03 ng/mL. The mean recoveries of the corresponding compounds were 98%‐110%. Serum levels of MK‐4, K1, and MK‐7 in postmenopausal women with osteoporosis were 0.890 ± 0.291 ng/mL, 0.433 ± 0.394 ng/mL, and 1.002 ± 1.020 ng/mL, respectively (mean ± SD). Serum levels of MK‐4, K1, and MK‐7 in postmenopausal women without osteoporosis were 0.825 ± 0.266 ng/mL, 0.493 ± 0.399 ng/mL, and 1.186 ± 1.076 ng/mL, respectively (mean ± SD).

Conclusion

New HPLC method for the determination of vitamins K1, MK‐4, and MK‐7 in serum was evaluated and validated. This method is highly specific and sensitive with the low limit of quantification.
The politics of tourism statistics
Authors: Pratt Stephen , Tolkach Denis
Published: January 2018

Tourism statistics are important for policymakers to make prudent decisions and for researchers to conduct rigorous research. However, statistics are inherently political. This article highlights three areas where tourism statistics appear misleading, serving industry and government interests. First, United Nations World Tourism Organization's interpretation of national sovereignty such that domestic tourism arrivals are counted as international tourism arrivals. Second, United Nations World Tourism Organization's use of terminology with respect to international tourists and international trips, using both terms interchangeably. Third, anomalies in tourism statistics reported by various governments and international organizations. More critical analysis needs to be undertaken when reporting data. Researchers should use official statistics with caution.
Increased soil methane emissions and methanogenesis in oil contaminated areas
Authors: Yang Juejie , Li Guanghe , Qian Yi , Zhang Fang
Published: January 2018

Crude oil exploration and related activities cause severe soil contamination and land degradation. However, how soil CH4 and CO2 fluxes respond to oil contamination is poorly understood. To address this question, we conducted in situ investigation of CH4 and CO2 emissions in the Shengli Oilfield, China. CH4 emissions from contaminated soils were 60–1,800 μg·m−2·hr−1, much higher than those from uncontaminated soils (29–33 μg·m−2·hr−1). CO2 fluxes of 2–78 mg·m−2·hr−1 were lower from contaminated soils compared with uncontaminated controls (78–104 mg·m−2·hr−1). The variance of CH4 and CO2 fluxes could be explained to 78.0% by soil properties and oil well age (p < .001) as suggested by the redundancy analysis and the variance partitioning analysis. On the basis of the Illumina MiSeq sequencing of the archaeal 16S rRNA gene, the relative abundance of methanogens over archaea increased by 8 times in contaminated soils compared with that in the uncontaminated soils, suggesting enhanced methanogenesis processes. The proportion of hydrogenotrophic methanogens over the total methanogens increased from 35% in the uncontaminated soil to 43% in the contaminated soils, consistent with the higher apparent fractionation factor (αC) in the stable isotope analysis. Both microbial and isotopic results suggested that the hydrogenotrophic methanogenesis relatively enhanced with the oil contamination, with less dominance of the acetoclastic methanogenesis. The dramatically increased CH4 emissions under oil contamination call for great attention as a potentially important anthropogenic source of CH4 in the atmosphere.
Comparative Study of Distribution of Active Sites According to Their Stereospecificity in Propylene Polymerization over the Traditional TiCl3 and Supported Titanium–Magnesium Catalysts with Different Composition
Authors: Nikolaeva Marina , Matsko Mikhail , Zakharov Vladimir
Published: January 2018

The preparative‐temperature rising elution fractionation method is used to obtain comparative data on contents of fractions with different microtacticities for polypropylene (PP) samples prepared using three catalytic systems: the traditional Ziegler–Natta (Z–N) catalyst δ‐TiCl3 and two types of supported titanium–magnesium catalysts: the “donor‐free” TiCl4/MgCl2 catalyst and TiCl4/MgCl2·nDBP catalyst (DBP – dibutylphthalate used as an internal donor) at polymerization with the same cocatalyst (AlEt3) in the absence and presence of an external donor (propyltrimetoxy silane). The separated individual PP fractions are also studied by gel permeation chromatography (molecular weight and molecular weight distribution) and differential scanning calorimetry. The results demonstrate general regularities and differences in the formation of active sites having different isospecificities for the traditional TiCl3‐based Z–N catalyst and highly active supported titanium–magnesium catalysts.
Borate‐Mediated Stereo‐ and Topo‐Selective Methylation of 1,4‐β‐Glucomannan
Authors: Zhang Qimeng , Mischnick Petra
Published: January 2018

Konjak glucomannan (KGM) is methylated with NaOH/MeI in water in the presence of borate and as a reference without this additive. With increasing equiv. of borate increasing suppression of 2‐ and 3‐O‐methylation of mannosyl residues (M) is observed, while glucosyl units (G) are mainly affected at O‐6, but to much lower extent. Raising the temperature and/or addition of acetone as a co‐solvent enhance reactivity, but at the cost of M/G regioselectivity. O‐Methyl konjac glucomannans (M‐KGM) with an average degree of substitution (DS) up to 0.8 and a DS ratio for G and M up to 2 are obtained. From liquid chromatrography–electrospray ionization–mass spectrometry (LC‐ESI‐MS) of the oligosaccharides obtained from M‐KGM, it is concluded that borate‐mediated transient protection might also depend on the location of M within KGM. Comparison with random and block models supports random distribution of M and G in KGM. Thermogravimetric analysis shows higher decomposition temperature of M‐KGMs with increasing DS.
Significant Improvement on Polybenzoxazine Toughness Achieved by Amine/Benzoxazine Copolymerization‐Induced Phase Separation
Authors: Zhao Yang , Xu Yazhen , Xu Qingbo , Fu Feiya , Zhang Yanyan , Endo Takeshi , Liu Xiangdong
Published: January 2018

Two commercially available amines, octanediamine (ODM) and m‐xylylenediamine (MXDM), are chosen for tough polybenzoxazine resin due to their controllable capability to cause phase separation during the copolymerization with benzoxazine monomers. The toughening behavior and phase separation of the cured resins are investigated using tensile tests and analyses of dynamic mechanical analysis (DMA), scanning electron microscope, and thermal gravimetry–gas chromatography/mass spectroscopy. The resulting networks show remarkable toughness without obvious degradation in thermomechanical performance. Especially, when ODM/MXDM molar ratio is 1:1, an elongation rate of 10.55% and a breaking strength of 82.67 Mpa, which are 86% and 128% higher than that of the neat benzoxazine resin, respectively, are achieved. These findings open a new way to improve toughness of brittle polybenzoxazine resins.
Structure–Property Relationships of Random Aromatic Copolyamide Membranes by the Partial N‐Methylation of Amide Linkages
Authors: Aiba Motohiro , Ito Kenji , Tokuyama Takahiro , Tomioka Hiroki , Higashihara Tomoya , Ueda Mitsuru , Matsumoto Hidetoshi
Published: January 2018

The internal and surface structures and transport properties of partially N‐methylated aromatic random copolyamides are reported. The results from positron annihilation lifetime spectroscopy demonstrate that the N‐methylation of the amide linkages in the polymer backbone increases the size of the free volume in the membrane. The time‐resolved water contact angle measurements also indicate that the N‐methylation of the amide linkages increases the chain mobility at the membrane surfaces and consequently enhances the water‐induced surface reorganization. The partial N‐methylation of aromatic copolyamides can be used to control the internal and surface structures of the membranes. In particular, the size of the free volume can be tuned by suppressing the hydrogen bonding between the polymer chains, improving the transport properties through the membranes.
Electrospun Antimicrobial PVDF‐DTAB Nanofibrous Membrane for Air Filtration: Effect of DTAB on Structure, Morphology, Adhesion, and Antibacterial Properties
Authors: Capkova Pavla , Kormunda Martin , Kolska Zdenka , Trögl Josef , Munzarova Marcela , Rysanek Petr
Published: January 2018

Antimicrobial polyvinylidene fluoride (PVDF) membrane modified by dodecyltrimethyl ammonium bromide (DTAB) has been electrospun using simple one‐step technology, where the modifying agent DTAB is dissolved in spinning solution. X‐ray photoelectron spectroscopy and electrokinetic analysis confirm reliably the presence of DTAB on the nanofibers surfaces; electrokinetic analysis shows the changes of zeta potential due to modification by DTAB. X‐ray diffraction shows that electrospinning converts the part of α phase (≈40%) present in PVDF powder into β phase with all trans (TTT) zigzag chains conformation in PVDF electrospun membrane. Surface modification does not affect the phase composition of PVDF nanofibers, just only leads to lower crystallinity (smaller size of crystallites) in PVDF nanofibers. DTAB causes the curling of fibers and their aggregation, what completely changed the membrane structure. DTAB‐modified membrane exhibits antibacterial properties against Staphylococcus aureus subsp. Aureus. Concentration of 0.5 wt% DTAB in spinning solution causes partial inhibition of bacterial growth only, while 1.0 wt% concentration leads to complete inhibition.
Rapid, Regioselective Living Ring‐Opening Metathesis Polymerization of Bio‐Derivable Asymmetric Tricyclic Oxanorbornenes
Authors: Naguib Mohamed , Schiller Tara L. , Keddie Daniel J.
Published: January 2018

The synthesis of a range of alkyl esters (methyl, n‐butyl, and n‐decyl) prepared via Steglich esterification of the thermodynamically controlled exo, exo Diels–Alder adduct of furfuryl alcohol and maleic anhydride is reported. Subsequent ring‐opening metathesis polymerization of these bio‐derivable tricyclic oxanorbornene analogs delivers polymers with targeted molar mass and low molar mass dispersity. The polymerizations are rapid with complete monomer conversion achieved within 15 min. Significantly, the presence of the cyclic lactone at the bridgehead of these monomers leads to polymers with high regioregularity (>85% head‐to‐tail) and high stereoregularity (>75% trans). The resultant polymers display both high thermal stability and high glass transition temperatures. This new class of oxanorbornene monomer, accessed from bio‐derivable furfuryl alcohol and maleic anhydride, may be further tailored to incorporate a range of functional moieties. Furthermore, the exceptional properties of the derived polymers indicate potential in a range of applications.
Fluid Flow and Distributive Mixing Analysis in the Cavity Transfer Mixer
Authors: Grosso Giovanna , Hulsen Martien A. , Overend Andrew , Anderson Patrick D.
Published: January 2018

In the polymer industry good mixing is essential to guarantee the characteristics of finished products. However, optimizing mixing devices is often difficult because mixing mechanisms are the result of the complex interaction between the moving elements and the non‐Newtonian fluids used. Full 3D simulations are computationally expensive and the complexity of the problem is often split into approximated subproblems. The present work focuses on a simplified 2D model of the Cavity Transfer Mixer, investigating stretching and folding mixing actions. Several geometrical and functioning parameters, such as cavity speed, cavity shape, intercavity distance, rotor–stator clearance, and fluid rheology are varied. Mixing is analyzed in terms of Poincaré maps and by simulating the evolution of fluid blobs. The intercavity distance is found to play a major role, enabling and governing the stretching actions inside the mixing device.
The effects of low levels of trivalent ions on a standard strain of Escherichia coli (ATCC 11775) in aqueous solutions
Authors: Deng Can , Li Xinpeng , Xue Xinkai , Pashley Richard M.
Published: January 2018

Considering the ever‐growing usage of trivalent salts in water treatment, for example, lanthanum salts in rare earth, AlCl3 and FeCl3, the effects of different trivalent cations on the bacterium Escherichia coli (E. coli) ATCC 11775 strain have been studied in aqueous solutions. From colony incubation studies, the colony‐forming unit (CFU) densities were found to decrease significantly in the presence of even low levels (10−5 mol/L) of lanthanum chloride. This level of reduction in CFU number is comparable to the results obtained using the known bacteriocidal cationic surfactant, C14TAB. By comparison, exposure of the cells to low levels of trivalent ion, aluminum and chromium ion solutions produced only modest reductions in CFU density. The results from the incubation studies suggest that the bacteriostatic mechanism of La3+ ions has similarities to that of the cationic surfactant, and different to that of the other trivalent ions. Size distribution and zeta potential measurements of E. coli cells and phospholipid vesicles in the presence of trivalent cations solutions suggested significant cell shrinkage probably caused by membrane disruption.
Determining the conductivity for a nonautonomous hyperbolic operator in a cylindrical domain
Authors: Beilina Larisa , Cristofol Michel , Li Shumin
Published: January 2018

This paper is devoted to the reconstruction of the conductivity coefficient for a nonautonomous hyperbolic operator an infinite cylindrical domain. Applying a local Carleman estimate, we prove the uniqueness and a Hölder stability in the determination of the conductivity using a single measurement data on the lateral boundary. Our numerical examples show good reconstruction of the location and contrast of the conductivity function in 3 dimensions.
Tuning Bis(imino)pyridyl Iron‐Catalyzed Ethylene Oligomerization by Modification of MAO with p‐BrPhOH
Authors: Zhang Wei , Ye Jian , Jiang Binbo , Wang Jingdai , Liao Zuwei , Huang Zhengliang , Yang Yongrong , Ye Zhibin
Published: January 2018

To reduce the simultaneous production of insoluble polymers during the bis(imino)pyridyl iron‐catalyzed ethylene oligomerization, in this study, p‐BrPhOH (4‐bromophenol) has been chosen as the most optimal modifier for the production of linear α‐olefins. It is found that the polymer share in the total products is largely reduced with the use of p‐BrPhOH as the modifier. The catalytic system also possesses a high activity with the liquid production maintained high level of linearity. Moreover, the introduction of p‐BrPhOH promoted the high‐temperature stability of the catalytic system, leading to the enhanced oligomerization activity as the catalytic system can catalyze ethylene oligomerization at higher temperatures. A characterization of the catalytic system with electron paramagnetic resonance shows that introduction of p‐BrPhOH significantly inhibits the formation of ferric ions, which can be the main active centers responsible for generating undesired insoluble polymers, thus this can largely retard the production of insoluble polymers during ethylene oligomerization.
Improved liver mapping by pixel‐wise curve fitting with adaptive neighborhood regularization
Authors: Wang Changqing , Zhang Xinyuan , Liu Xiaoyun , He Taigang , Chen Wufan , Feng Qianjin , Feng Yanqiu
Published: January 2018

Purpose

To improve liver
mapping by incorporating adaptive neighborhood regularization into pixel‐wise curve fitting.

Methods

Magnetic resonance imaging
mapping remains challenging because of the serial images with low signal‐to‐noise ratio. In this study, we proposed to exploit the neighboring pixels as regularization terms and adaptively determine the regularization parameters according to the interpixel signal similarity. The proposed algorithm, called the pixel‐wise curve fitting with adaptive neighborhood regularization (PCANR), was compared with the conventional nonlinear least squares (NLS) and nonlocal means filter‐based NLS algorithms on simulated, phantom, and in vivo data.

Results

Visually, the PCANR algorithm generates
maps with significantly reduced noise and well‐preserved tiny structures. Quantitatively, the PCANR algorithm produces
maps with lower root mean square errors at varying
values and signal‐to‐noise‐ratio levels compared with the NLS and nonlocal means filter‐based NLS algorithms. For the high
values under low signal‐to‐noise‐ratio levels, the PCANR algorithm outperforms the NLS and nonlocal means filter‐based NLS algorithms in the accuracy and precision, in terms of mean and standard deviation of
measurements in selected region of interests, respectively.

Conclusions

The PCANR algorithm can reduce the effect of noise on liver
mapping, and the improved measurement precision will benefit the assessment of hepatic iron in clinical practice. Magn Reson Med 80:792–801, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
Interleaved susceptibility‐weighted and FLAIR MRI for imaging lesion‐penetrating veins in multiple sclerosis
Authors: Gabr Refaat E. , Pednekar Amol S. , Kamali Arash , Lincoln John A. , Nelson Flavia M. , Wolinsky Jerry S. , Narayana Ponnada A.
Published: January 2018

Purpose

To simultaneously image brain lesions and veins in multiple sclerosis.

Methods

An interleaved sequence was developed to simultaneously acquire 3‐dimensional
‐weighted (or susceptibility‐weighted (SW)) and fluid‐attenuated inversion recovery (FLAIR) images on a 3T MRI system. The pulse sequence parameters were calculated to minimize signal perturbation from steady state while maintaining acceptable image contrast and scan time. Fifteen multiple sclerosis patients were enrolled in this prospective study and underwent a standard multiple sclerosis imaging protocol. In addition, SW and FLAIR images were acquired separately and also in an interleaved manner. The SW and FLAIR images were combined into one image to visualize lesions and penetrating veins. The contrast ratios between white matter lesions and penetrating veins were compared between the interleaved sequence and the individual noninterleaved acquisitions.

Results

Interleaved scanning of the FLAIR and the SW pulse sequences was achieved, producing aligned images, and with similar image contrast as in the noninterleaved images. A total of 1076 lesions were identified in all patients on the combined SW‐FLAIR image, of which 968 lesions (90%) had visible penetrating veins. Lesion‐to‐vein contrast ratio was 32.7 ± 17.9 (mean ± standard deviation) for the interleaved sequence compared with 28.1 ± 13.7 using the separate acquisitions (P < 0.001).

Conclusion

The feasibility of interleaved acquisition of SW and FLAIR images was demonstrated. This sequence provides self‐registered images and facilitates the visualization of veins in brain lesions. Magn Reson Med 80:1132–1137, 2018. © 2018 International Society for Magnetic Resonance in Medicine.
Characterization of mouse neuro‐urological dynamics in a novel decerebrate arterially perfused mouse (DAPM) preparation
Authors: Ito Hiroki , Drake Marcus J. , Fry Christopher H. , Kanai Anthony J. , Pickering Anthony E.
Published: January 2018

Aim

To develop the decerebrate arterially perfused mouse (DAPM) preparation, a novel voiding model of the lower urinary tract (LUT) that enables in vitro‐like access with in vivo‐like neural connectivity.

Methods

Adult male mice were decerebrated and arterially perfused with a carbogenated, Ringer's solution to establish the DAPM. To allow distinction between central and peripheral actions of interventions, experiments were conducted in both the DAPM and in a “pithed” DAPM which has no brainstem or spinal cord control.

Results

Functional micturition cycles were observed in response to bladder filling. During each void, the bladder showed strong contractions and the external urethral sphincter (EUS) showed bursting activity. Both the frequency and amplitude of non‐voiding contractions (NVCs) in DAPM and putative micromotions (pMM) in pithed DAPM increased with bladder filling. Vasopressin (>400 pM) caused dyssynergy of the LUT resulting in retention in DAPM as it increased tonic EUS activity and basal bladder pressure in a dose‐dependent manner (basal pressure increase also noted in pithed DAPM). Both neuromuscular blockade (vecuronium) and autonomic ganglion blockade (hexamethonium), initially caused incomplete voiding, and both drugs eventually stopped voiding in DAPM. Intravesical acetic acid (0.2%) decreased the micturition interval. Recordings from the pelvic nerve in the pithed DAPM showed bladder distention‐induced activity in the non‐noxious range which was associated with pMM.

Conclusions

This study demonstrates the utility of the DAPM which allows a detailed characterization of LUT function in mice.
Enrollment in early‐phase clinical trials in pediatric oncology: The experience at Institut Curie
Authors: Surun Aurore , Dujaric Marie‐Églantine , Aerts Isabelle , Orbach Daniel , Jiménez Irène , Pacquement Hélène , Schleiermacher Gudrun , Bourdeaut Franck , Michon Jean , Dupont Jean‐Claude K. , Doz François
Published: January 2018

Background

The European Paediatric Regulation was introduced in 2007 to facilitate access to new medicines for children. Our study explored accessibility of early‐phase trials in pediatric oncology, in line with the European Paediatric Regulation, to identify the reasons for not inviting patients to participate, parents’ refusal, or inclusion failure.

Procedure

We conducted a retrospective chart review at Institut Curie, Paris, for all pediatric patients whose cancer progressed despite known effective treatments between July 2010 and December 2013.

Results

Out of 100 patients in the palliative phase, 52 received one or more invitations to participate in early‐phase trials. Twenty parents declined the invitation, mainly prioritizing quality of life or fearing constraints. Fourteen inclusions failed despite parental approval, mostly due to rapid clinical deterioration. Five patients received no invitations because no early‐phase trials were available. Major reasons for noninclusion in the 43 remaining patients were presence of exclusion criteria or other physical factors, preference for conventional treatment, constraints, psychological factors, and follow‐up in another hospital after moving.

Conclusions

The Paediatric Regulation has led to increased availability of early‐phase trials. Better timing of the proposal, designing less constraining early‐phase trials, reducing waiting lists, and improving information for parents and children would facilitate pediatric access to new medicines.
Improved efficiencies of hybrid organic light‐emitting diodes using efficient electron injection layer
Authors: Jayabharathi Jayaraman , Nethaji Pavadai , Thanikachalam Venugopal , Jeeva Palanivel , Ramya Ramaiyan
Published: January 2018

Hybrid organic‐inorganic light‐emitting diodes were developed with pristine ZnO (2.0 wt%) and Cu‐doped ZnO (2.0 wt%) as electron injection layer and iridium(III)‐bis‐2‐(4‐fluorophenyl)‐1‐(naphthalen‐1‐yl)‐1H‐phenanthro[9,10‐d]imidazole (acetylacetonate) [Ir(fpnpi)2 (acac)] as green emissive layer (521 nm). The pristine ZnO and Cu‐doped ZnO are deposited at indium tin oxide cathode and emissive layer interface. The electroluminescent performances increased by electron injection layer–Cu‐doped ZnO compared with ZnO‐based device because Cu‐doped ZnO injects electron efficiently result in balanced h+ − e− recombination in emissive layer than ZnO‐based device. The Cu‐doped ZnO (2.0 %) device shows luminance (L) of 10 982 cd/m2 at 23.0 V (ZnO, 1450 cd/m2 at 23.0 V).