bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypoxia‐induced tRNA‐derived fragments, novel regulatory factor for doxorubicin resistance in triple‐negative breast cancer
Authors: Cui Yangyang , Huang Yue , Wu Xiaowei , Zheng Mingjie , Xia Yiqin , Fu Ziyi , Ge Han , Wang Shui , Xie Hui
Published: October 2018

Triple‐negative breast cancer (TNBC) is an aggressive subtype of epithelial breast malignancy, and chemoresistance is the major obstacle for cancer therapy. TNBC is associated with a hypoxic phenotype, and hypoxia contributes to the chemoresistance in breast cancer. Transfer RNA‐derived fragments (tDRs) represent a new class of small noncoding RNAs that can be induced specifically by hypoxia. Here, we conducted a comparative analysis of the aberrant expression of tDRs in hypoxia‐treated TNBC cell lines through the use of high‐throughput sequencing technique. Quantitative real‐time polymerase chain reaction was used to validate the differently expressed tDRs between two samples. The results showed that tDR‐0009 [derived from transfer RNA (tRNA)Gly‐GCC‐1‐1] and tDR‐7336 (derived from tRNA
Gly‐GCC‐1–2) were significantly upregulated when the SUM‐1315 cell lines were stimulated by hypoxia. Gene ontology (GO) and pathway analysis indicated that these two upregulated tDRs were mainly involved in maintenance of stem cell population and cellular response to interleukin (IL)‐6, which may be the underlying mechanism of hypoxia‐induced tDRs that facilitate the doxorubicin resistance in TNBC. The protein–protein interaction network for predicted target genes established by the STRING database manifested that tDR‐0009 (tDR‐7336) might be involved in the chemoresistance of TNBC via regulation of the activation of phosphorylation of STAT3. In summary, our study provided a comprehensive analysis of the deviant expression profiling of tDRs in hypoxia‐treated TNBC cell lines. Specific tDRs may be a new class of regulatory factors involved in the hypoxia‐induced chemoresistance in TNBC, and they could serve as potential biomarkers and intervention targets.
High fat diet reduces the expression of miRNA‐29b in heart and increases susceptibility of myocardium to ischemia/reperfusion injury
Authors: Guedes Elaine Castilho , da Silva Ivson Bezerra , Lima Vanessa Morais , Miranda Juliane B. , Albuquerque Rudá P. , Ferreira Julio C. B. , Barreto‐Chaves Maria Luiza M. , Diniz Gabriela Placoná
Published: October 2018

Several studies have shown the role of microRNAs (miRNAs) in myocardial dysfunction in response to ischemia/reperfusion (I/R). In this study, we investigated the impact of high fat (HF) diet in the myocardial susceptibility to I/R injury, as well as in the expression of miRNA‐29b. Isolated heart experiments using the ex vivo Langendorff perfusion model were used to induce cardiac I/R injury. HF diet‐induced cardiac hypertrophy and impaired cardiac functional recovery after I/R. miRNA‐29b, which targets Col1, was reduced in the heart of HF diet‐fed mice, whereas the cardiac expression of Col1 was increased. In addition, hypoxia–reoxygenation (H/R) reduced the expression of miRNA‐29b in cardiomyoblasts cultures. However, the overexpression of miRNA‐29b in cardiomyoblasts reduced p53 mRNA levels and H/R injury, suggesting that downregulation of miRNA‐29b may be involved in I/R injury. Together, our findings suggest that the reduced expression of miRNA‐29b may be involved in the deteriorated cardiac functional recovery following I/R in obese mice.
microRNA modified tumor‐derived exosomes as novel tools for maturation of dendritic cells
Authors: Taghikhani Adeleh , Hassan Zuhair Mohammad , Ebrahimi Marzieh , Moazzeni Seyyed‐Mohammad
Published: October 2018

Tumor‐derived exosomes (TEX) are known by their immune suppression effects as well as initiation mediators in cancer progression and metastasis. Meanwhile, they are appropriate sources to induce immunity against tumor cells, as consist of tumor specific and associated antigens. The aim of the current study is modifying TEX with microRNA miR‐155, miR‐142, and let‐7i, to enhance their immune stimulation ability and induce potent dendritic cells (DC). For this, exosomes were isolated from mouse mammalian breast cancer cell line; 4T1, and subjected to miR‐155, miR‐142, and let‐7i by electroporation. Immature DCs were generated from mouse bone marrow in the presence of interleukin‐4 (IL‐4) and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF). To mature DCs, lipopolysaccharide (LPS), TEX, and modified TEX were used. The expression level of miRNAs and their target genes (IL‐6, IL‐17, IL‐1b, TGFβ, SOCS1, KLRK1, IFNγ, and TLR4) was determined. TEX were nanovesicles with spheroid morphology which expressed CD81, CD63, and TSG101, as exosome markers, at protein level. MHCII, CD80, and CD40 as maturation markers were assessed by flow cytometry. Overexpression of miRNAs were confirmed in exosomes and mDCs. Up and downregulation of target genes confirmed the gene network in DC maturation. We found that Let‐7i could efficiently induce the DC maturation, as well as miR‐142 and miR‐155 have enhancing effects. These findings reveal that the modified TEX would be a hopeful cell‐free vaccine for the cancer treatment.
Effects of macrophages and CXCR2 on adipogenic differentiation of bone marrow mesenchymal stem cells
Authors: Cao Dingding , Ma Feifei , Ouyang Shengrong , Liu Zhuo , Li Yuanyuan , Wu Jianxin
Published: October 2018

Macrophages and many chemokines are closely associated with the adipogenic differentiation of bone marrow mesenchymal stem cells (MSCs), but their roles in adipogenesis and the underlying mechanisms are not fully understood. Here, we first investigated the influence of macrophages on the differentiation of MSCs in vitro. We found that RAW246.7 macrophages cocultured with MSCs strongly blocked the differentiation progress and inhibited the expression of C‐X‐C motif chemokine ligand 1 (CXCL1) during adipogenesis. Coculture with MSCs mainly induced macrophages toward M2 polarization. In addition, the expression of CXCL1 and its receptor, C‐X‐C chemokine receptor type 2, CXCR2 are high during adipogenic differentiation of MSCs and not in mature adipocytes. Although CXCL1 had no effect on adipogenesis, treatment with a specific CXCR2 inhibitor, SB225002, hampered the adipogenic differentiation of MSCs. Blocking CXCR2 decreased p38 and Elk1 phosphorylation but increased the extracellular signal–regulated kinase (ERK) phosphorylation at the initial stage of adipogenesis, which suppressed the phosphorylation of p38/ERK‐Elk1 at the late stage. Inhibition of ERK had similar effects on adipogenesis and Elk1 phosphorylation. Our data suggest that MSCs interact with macrophages during adipogenic differentiation. CXCR2 regulates the adipogenic differentiation of MSCs by altering the activation of the p38/ERK‐Elk1 signaling pathway.
Combination therapy of sorafenib with mesenchymal stem cells as a novel cancer treatment regimen in xenograft models of hepatocellular carcinoma
Authors: Seyhoun Iman , Hajighasemlou Saieh , Muhammadnejad Samad , Ai Jafar , Nikbakht Mohsen , Alizadeh Ali akbar , Hosseinzadeh Faezeh , Mirmoghtadaei Milad , Seyhoun Seyed Moein , Verdi Javad
Published: October 2018

Aim

Hepatocellular carcinoma (HCC) is the most common liver malignancy and the second leading cause of cancer‐related deaths in the world. Sorafenib is the first‐line treatment of HCC. Although sorafenib has positive effects on the survival of patients, novel therapeutic strategies are needed to extend survival and improve the efficacy of sorafenib. This study combines sorafenib with mesenchymal stem cells (MSCs) as a new approach to enhance the efficacy of sorafenib.

Material and methods

A subcutaneous xenograft model of HCC, established by human HepG2 cell lines, was implanted into the flank of nude mice and was used to evaluate tumor growth after treatment with sorafenib alone or in combination with MSCs. The aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine levels were measured for safety assessment. Histopathological studies were performed using hematoxylin and eosin staining, and immunohistochemistry tests were performed to evaluate proliferation (Ki67) and angiogenesis (CD34). The TUNEL assay was used to detect apoptosis and measure the expression of major inflammatory cytokines (IL‐1a, IL‐10, and TNF‐α) with real‐time polymerase chain reaction.

Result

Sorafenib, in combination with MSCs, strongly inhibited tumor growth in the xenograft model. Furthermore, the combination therapy significantly inhibited HCC cell proliferation, decreased tumor angiogenesis, and induced apoptosis and maintained antitumor‐associated anti‐inflammatory effects of MSCs.

Conclusion

This combination therapy strategy could be used as a new therapeutic approach to the treatment of HCC that significantly improves upon the results achieved using sorafenib as monotherapy.
Biodegradation characteristics and genomic functional analysis of indole‐degrading bacterial strain Acinetobacter sp. JW
Authors: Zhang Xuwang , Jing Jiawei , Zhang Lizhi , Song Zhaojian , Zhou Hao , Wu Minghuo , Qu Yuanyuan , Liu Lifen
Published: October 2018

BACKGROUND

Indole, an important type of N‐heterocyclic aromatic compound, is considered a toxic and odorous pollutant in coking and municipal wastewater. For efficient bioremediation of indole‐containing wastewater, an indole‐degrading bacterial strain JW was isolated from activated sludge in this study. The indole biodegradation characteristics and the whole‐genome sequence of strain JW were also determined.

RESULTS

Strain JW, capable of utilizing indole as the sole carbon and nitrogen source, was identified as Acinetobacter sp. based on 16S rRNA gene sequence analysis. It was able to completely degrade 100 mg L−1 indole within 20 h, and transform organic nitrogen to ammonia (NH4+‐N) and nitrate (NO3−‐N). Meanwhile, strain JW also presented high capacity for indole degradation at a range of initial indole concentrations (25–200 mg L−1) and pH (6.0–8.0). The key metabolites during indole biodegradation were identified by liquid chromatography coupled to Q‐Exactive high resolution mass spectrometry, and included isatin, anthranilate, salicylate, catechol and indigo. The whole‐genome sequence of strain JW revealed the possible functional genes related to indole biodegradation, such as iif genes, ant genes and downstream metabolic genes. Thus, an indole biodegradation mechanism was proposed based on metabolites identification and genomic analysis.

CONCLUSION

The results suggested that Acinetobacter sp. JW could be a promising biological candidate for bioremediation of indole, and the useful genetic information might enrich our understanding of microbial degradation of indole. © 2018 Society of Chemical Industry
Twenty years of daily metabolism show riverine recovery following sewage abatement
Authors: Arroita Maite , Elosegi Arturo , Hall Robert O.
Published: October 2018

Abstract

Human activities have altered the environmental controls on river metabolism, i.e., gross primary production (GPP) and ecosystem respiration (ER). These coupled processes affect water quality, CO2 emissions, and biodiversity. Efforts to mitigate these impacts often lack long‐term, high‐resolution data needed to assess their success. Here, we estimated a 20‐yr time series of daily metabolism from dissolved oxygen (DO) data following pollution abatement (sewage treatment) in the Oria River, Spain. Ammonium concentration declined immediately after sewage abatement, whereas dissolved organic matter absorbance (proxy for concentration) declined slowly. Summer GPP declined with ammonium concentration. ER declined more strongly but more gradually than GPP and was driven by lower rates of autotrophic respiration (AR) and heterotrophic respiration following sewage treatment. Reduced AR reflected a decrease in the fraction of daily GPP being respired by algae themselves. Decline in ER caused net ecosystem production to increase from highly negative to approximately zero. Diel DO swings also declined and episodes of hypoxia nearly disappeared following reduced metabolic rates, and were paralleled by lower benthic chlorophyll a, increased macroinvertebrate indices, and a recovery of fish assemblages. Overall, wastewater treatment plants installation constrained river metabolism, greatly improved water quality, and enabled invertebrates and fish to recolonize the river. However, most variables responded gradually and these changes would not have been evident with short‐term DO data. These gradual responses revealed the need of long‐term, high‐resolution data to gain insight into long‐temporal scale responses superimposed on short‐temporal scale metabolic variation, especially in the current context of climate and land‐use change.
Multidecadal carbon sequestration in a headwater boreal lake
Authors: Hall Britt D. , Hesslein Raymond H. , Emmerton Craig A. , Higgins Scott N. , Ramlal Patricia , Paterson Michael J.
Published: October 2018

Abstract

Dissolved organic carbon (DOC) was measured continuously since 1970 in a pristine headwater boreal lake and its catchment at the IISD‐Experimental Lakes Area (Ontario, Canada). Mass balanced accounting of DOC concentrations in precipitation, watershed runoff, and inflow and outflow streams, and integrated weekly hydrological data determined annual mass flux of DOC to and from the lake. Inputs minus outputs represented two residual terms: (1) mineralization and evasion of CO2 and (2) DOC flocculation and sediment burial. Accumulation of organic carbon in sediment cores estimated permanent storage and evasion was calculated by subtraction of burial from the annual retention over 40 yr (1971–2010). Terrestrial sources accounted for 92% ± 1% of DOC load; 37% ± 2% of which was lost via the outflow. About 40% ± 3% of DOC load accumulated in sediments and 23 ± 3% was lost as CO2. Over 40 yr, C sequestration in sediments was a more important sink than evasion or outflow. We explore the fate of DOC during decade long periods of differing precipitation patterns. Loading and loss via the outflow was higher in wet (1990–2010) compared to dry (1980–1990) years. Due to longer DOC processing times when water residence times are longer, it is possible that if drought increases in the boreal forest, the efficiency of headwater lakes to sequester C in sediments maybe greater than in wet periods.
Effects of partitioning parameters in quenching and partitioning on microstructure and mechanical properties of an ultra‐high strength low‐alloy steel
Authors: Jafari R. , Kheirandish S. , Mirdamadi S.
Published: October 2018

In this research the effects of partitioning temperature and time in quenching and partitioning (Q&P) heat treatment was studied by applying the two‐step quenching and partitioning on a novel low‐alloy medium carbon steel. Partitioning was carried out at 250 °C and 300 °C for various times to obtain different amount of retained austenite and carbide precipitation. Microstructural studies revealed that after 3000 s at 250 °C same as 500 s at 300 °C, the matrix transformed from martensite to tempered martensite and lower bainite. The increase in partitioning time, due to carbide precipitation led to yield strength improvement, while it caused the reduction in elongation. The tensile test results showed that all quenching and partitioning specimens had tensile strengths higher than 1500 MPa and yield strengths over 1000 MPa.
Entwicklung von HPPMS‐Al2O3‐Beschichtungen für die Zerspanung von schwer zerspanbaren Werkstoffen
Authors: Bobzin K. , Brögelmann T. , Kruppe N.C. , Basturk S. , Klocke F. , Gerschwiler K. , Kölker W. , Bolz S. , Kohlscheen J.
Published: October 2018

Die Beschichtung von Zerspanwerkzeugen hat in der Vergangenheit entscheidend zu Verbesserungen und Leistungssteigerungen in der Zerspantechnik beitragen können. Aluminiumoxid (Al2O3) nimmt hierbei aufgrund einer Vielzahl an Eigenschaften, wie Warmhärte, Oxidations‐, Diffusions‐ und chemischer Beständigkeit eine wichtige Rolle ein. Physical Vapor Deposition (PVD) Al2O3‐Beschichtungen, die mittels medium frequency Magnetron Sputtering (mfMS) hergestellt werden, haben ihre Leistungsfähigkeit in der Zerspanung von schwer zerspanbaren Werkstoffen bereits bewiesen. Die High Power Pulsed Magnetron Sputtering (HPPMS)‐Technologie kann zu weiteren Verbesserungen der Schichtmorphologie und ‐eigenschaften aufgrund hoher Ionisation des abgesputterten Materials führen. In diesem Zusammenhang ist die Abscheidung von Al2O3mittels HPPMS bisher wenig erforscht. Bisher ist noch unklar, welche Phasen abgeschieden werden bzw. wie die Prozessparameter die Phasenbildung beeinflussen. Ziel der Untersuchungen ist es, die Erkenntnisse über die Abscheidung von PVD‐Al2O3‐Schichten und deren Einsatzverhalten auf die industrielle Ebene mittels HPPMS zu übertragen, neue Einsatzbereiche des potenzialträchtigen Schichtsystems zu erschließen und somit einen Beitrag zur Weiterentwicklung in der Zerspantechnik von schwer zerspanbaren Werkstoffen zu leisten.
Hyaluronan‐CD44/RHAMM interaction‐dependent cell proliferation and survival in lung cancer cells
Authors: Song Jung Min , Im Jintaek , Nho Richard Seonghun , Han Yong Hwan , Upadhyaya Pramod , Kassie Fekadu
Published: October 2018

Although members of the hyaluronan (HA)‐CD44/HA‐mediated motility receptor (RHAMM) signaling pathway have been shown to be overexpressed in lung cancer, their role in lung tumorigenesis is unclear. In the present study, we first determined levels of HA and its receptors CD44 and RHAMM in human non‐small cell lung cancer (NSCLC) cells and stromal cells as well as mouse lung tumors. Subsequently, we examined the role of HA‐CD44/RHAMM signaling pathway in mediating the proliferation and survival of NSCLC cells and the cross‐talk between NSCLC cells and normal human lung fibroblasts (NHLFs)/lung cancer‐associated fibroblasts (LCAFs). The highest levels of HA and CD44 were observed in NHLFs/LCAFs followed by NSCLC cells, whereas THP‐1 monocytes/macrophages showed negligible levels of both HA and CD44. Simultaneous silencing of HA synthase 2 (HAS2) and HAS3 or CD44 and RHAMM suppressed cell proliferation and survival as well as the EGFR/AKT/ERK signaling pathway. Exogenous HA partially rescued the defect in cell proliferation and survival. Moreover, conditioned media (CM) generated by NHLFs/LCAFs enhanced the proliferation of NSCLC cells in a HA‐dependent manner as treatment of NHLFs and LCAFs with HAS2 siRNA, 4‐methylumbelliferone, an inhibitor of HASs, LY2228820, an inhibitor of p38MAPK, or treatment of A549 cells with CD44 blocking antibody suppressed the effects of the CM. Upon incubation in CM generated by A549 cells or THP‐1 macrophages, NHLFs/LCAFs secreted higher concentrations of HA. Overall, our findings indicate that targeting the HA‐CD44/RHAMM signaling pathway could be a promising approach for the prevention and therapy of lung cancer.
Combined Dystonia With Self‐Mutilation in 6‐Pyruvoyl‐Tetrahydropterin Synthase (PTPS) Deficiency: A Case Report
Authors: Latorre Anna , Salgado Paula , Salari Mehri , Jesuthasan Aaron , Bhatia Kailash P.
Published: October 2018

View Supplementary Video 1
Determinants of moral hazard in research and development supply relations: Empirical results beyond the agency‐theory explanation
Authors: Kloyer Martin , Helm Roland , Aust Christin
Published: October 2018

Moral hazard can hinder both the realization and the effectiveness of research and development (R&D) supply relations. However, to the best of our knowledge, there have been no empirical studies investigating the determinants of moral hazard under the specific circumstances of R&D supply relations. Based on a study on 104 cases, this article will help to fill that gap. The results not only confirm information asymmetries as determinants, as predicted by principal‐agent theory, but also reveal surprising effects of additional factors. Thus, we show that the general explanation of moral hazard needs to be adapted to the specifics of a concrete exchange situation.
CORE‐PI: Non‐iterative convolution‐based reconstruction for parallel MRI in the wavelet domain
Authors: Shimron Efrat , Webb Andrew G. , Azhari Haim
Published: October 2018

Purpose

To develop and test a novel parameter‐free non‐iterative wavelet domain method for reconstruction of undersampled multicoil MR data.

Theory and Methods

A linear parallel MRI method that operates in the Stationary Wavelet Transform (SWT) domain is proposed. The method is coined COnvolution‐based REconstruction for Parallel MRI (CORE‐PI). This method computes the SWT of the unknown MR image directly from subsampled k‐space measurements, without modifying the RF excitation pulse. It then reconstructs the image using the wavelet filter bank approach, with simple linear computations. The CORE‐PI implementation is demonstrated by experiments with a numeric brain phantom and in vivo brain scans data, with various wavelet types and high reduction factors. It is compared to the well‐known parallel MRI methods GRAPPA and l1‐SPIRiT.

Results

The experimental results show that CORE‐PI is suitable for different 1D Cartesian k‐space undersampling schemes, including regular and irregular ones, and for wavelets of different families. CORE‐PI accurately reconstructs the SWT coefficients of the unknown MR image; this wavelet‐domain decomposition is fully computed despite the k‐space undersampling. Furthermore, CORE‐PI provides high‐quality final reconstructions, with an average NRMSE of 0.013, which is significantly lower than that obtained by GRAPPA and l1‐SPIRiT. Moreover, CORE‐PI offers significantly faster computation times: the typical CORE‐PI runtime is about 60 seconds, which is about 20% shorter than that of l1‐SPIRiT and 55%–75% shorter than that of GRAPPA.

Conclusion

COnvolution‐based REconstruction for Parallel MRI advantageously offers: (a) flexible 1D undersampling of a Cartesian k‐space, (b) a parameter‐free non‐iterative implementation, (c) reconstruction performance comparable or better than that of GRAPPA and l1‐SPIRiT, and (d) robust fast computations.
A framework for Fourier‐decomposition free‐breathing pulmonary 1H MRI ventilation measurements
Authors: Guo Fumin , Capaldi Dante P.I. , McCormack David G. , Fenster Aaron , Parraga Grace
Published: October 2018

Purpose

To develop a rapid Fourier decomposition (FD) free‐breathing pulmonary 1H MRI (FDMRI) image processing and biomarker pipeline for research use.

Methods

We acquired MRI in 20 asthmatic subjects using a balanced steady‐state free precession (bSSFP) sequence optimized for ventilation imaging. 2D 1H MRI series were segmented by enforcing the spatial similarity between adjacent images and the right‐to‐left lung volume–ratio. The segmented lung series were co‐registered using a coarse‐to‐fine deformable registration framework that used dual optimization techniques. All pairwise registrations were implemented in parallel and FD was performed to generate 2D ventilation‐weighted maps and ventilation‐defect‐percent (VDP). Lung segmentation and registration accuracy were evaluated by comparing algorithm and manual lung‐masks, deformed manual lung‐masks, and fiducials in the moving and fixed images using Dice‐similarity‐coefficient (DSC), mean‐absolute‐distance (MAD), and target‐registration‐error (TRE). The relationship of FD‐VDP and 3He‐VDP was evaluated using the Pearson‐correlation‐coefficient (r) and Bland Altman analysis. Algorithm reproducibility was evaluated using the coefficient‐of‐variation (CoV) and intra‐class‐correlation‐coefficient (ICC) for segmentation, registration, and FD‐VDP components.

Results

For lung segmentation, there was a DSC of 95 ± 1.5% and MAD of 2.3 ± 0.5 mm, and for registration there was a DSC of 97 ± 0.8%, MAD of 1.6 ± 0.4 mm and TRE of 3.6 ± 1.2 mm. Reproducibility for segmentation DSC (CoV/ICC = 0.5%/0.92), registration TRE (CoV/ICC = 0.4%/0.98), and FD‐VDP (Cov/ICC = 3.9%/0.97) was high. The pipeline required 10 min/subject. FD‐VDP was correlated with 3He‐VDP (r = 0.69, P < 0.001) although there was a bias toward lower FD‐VDP (bias = −4.9%).

Conclusions

We developed and evaluated a pipeline that provides a rapid and precise method for FDMRI ventilation maps.
A new approach to Z‐spectrum acquisition: prospective baseline enhancement (PROBE) for CEST/Nuclear Overhauser Effect
Authors: Lenich Tobias , Pampel André , Mildner Toralf , Möller Harald E.
Published: October 2018

Purpose

To develop a prospective baseline enhancement that compensates for intermingled background effects in Z‐spectra to achieve sensitivity enhancement of peaks related to CEST and nuclear Overhauser effect.

Methods

An MRI sequence–specific compensation of background effects is achieved through variation of the pulsed saturation power, , with the chemical shift, . After a “scout acquisition” of a standard Z‐spectrum, the background is modeled through an appropriate spin system. Subsequently, an optimization procedure yields values that compensate for background contributions yielding a flat baseline. Contributions from metabolites not considered in the optimization procedure are enhanced as distinct perturbations to the baseline. For experimental verification, mapping of the lactate concentration in the presence of cross‐linked bovine serum albumin was performed in phantoms at 7 T. As proof of concept, explorative experiments were performed in healthy human subjects at 3 T.

Results

Nuisance contributions from direct water saturation, macromolecular magnetization transfer, and exchanging background protons were successfully removed from the Z‐spectrum in phantoms and in brain tissue. The lactate methyl, methine, and hydroxyl peaks were readily observable in vitro. The peak areas correlated linearly with known concentrations. Improvement of the detection limit was achieved by a sparse distribution of saturation frequencies, allowing for more efficient signal averaging.

Conclusion

An optimization framework for high‐resolution metabolite mapping by means of CEST/nuclear Overhauser effect was developed. It offers full flexibility to select spin‐pool moieties, whose influence on the Z‐spectrum will be compensated. Deviations from this background model will provide a contrast at the respective offset frequencies.
Reduction techniques for the prize collecting Steiner tree problem and the maximum‐weight connected subgraph problem
Authors: Rehfeldt Daniel , Koch Thorsten , Maher Stephen J.
Published: October 2018

The concept of reduction has frequently distinguished itself as a pivotal ingredient of exact solving approaches for the Steiner tree problem in graphs. In this article we broaden the focus and consider reduction techniques for three Steiner problem variants that have been extensively discussed in the literature and entail various practical applications: The prize‐collecting Steiner tree problem, the rooted prize‐collecting Steiner tree problem and the maximum‐weight connected subgraph problem. By introducing and subsequently deploying numerous new reduction methods, we are able to drastically decrease the size of a large number of benchmark instances, already solving more than 90% of them to optimality. Furthermore, we demonstrate the impact of these techniques on exact solving, using the example of the state‐of‐the‐art Steiner problem solver SCIP‐Jack.
Optimizing ground station networks for free space optical communications: Maximizing the data transfer
Authors: Capelle Mikaël , Huguet Marie‐José , Jozefowiez Nicolas , Olive Xavier
Published: October 2018

Free space optical communications are becoming a mature technology to cope with the needs of high data rate payloads for future low‐earth orbiting observation satellites. However, they are strongly impacted by clouds. In this paper, we aim to find a network of optical ground stations maximizing the percentage of data acquired by a low‐earth orbiting satellite that can be transferred to the Earth, taking into consideration cloud information. This problem can be separated in two parts and solved hierarchically: the selection of a network of optical ground stations and the assignment of downloads to visibility windows of the stations. We present theoretical and practical results regarding the complexity of the latter subproblem and propose a dynamic programming algorithm to solve it. We combine this algorithm with two methods for the enumeration of the stations, and compare them with a mixed integer linear program (MILP). Results show that even if the MILP can solve scenarios over small horizons, the hierarchical approaches outperform it in term of computation time while still achieving optimality for larger instances.
Synthesis and characterization of biodegradable multicomponent amphiphilic conetworks with tunable swelling through combination of ring‐opening polymerization and “click” chemistry method as a controlled release formulation for 2,4‐dichlorophenoxyacetic acid herbicide
Authors: Dabbaghi Alaleh , Rahmani Sohrab
Published: October 2018

Multicomponent (two, three, and four component) amphiphilic conetworks (APCNs) with tunable swelling behaviors were fabricated through the ring opening polymerization and click chemistry utilizing various combinations of azide and alkyne functionalized poly (ethylene glycol) (PEG) and poly (caprolactone) (PCL) precursors. Prepare azido‐terminated star‐shaped PCL, azido‐terminated PEG, alkyne‐terminated PEG, and propargylated pentaerythritol were characterized by hydrogen‐1 proton nuclear magnetic resonance (1H NMR) and Fourier‐transform infrared (FT‐IR) spectroscopy. The morphology and thermal behavior of the APCNs were studied by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The swelling behavior of APCNs could be manipulated through an establishment of a balance between hydrophilic segments, hydrophobic segments, and cross‐linking density. The 2,4‐dichlorophenoxyacetic acid (2,4‐D) herbicide was entrapped in APCNs as a model agrochemical to study the release profile from APCNs. The obtained results showed that the release of 2,4‐D could be controlled by the swelling degree of APCNs. Finally, the biodegradability rates of APCNs were investigated in agricultural soil. The results exhibited that the decrease in the swelling degree led to decreased degradation rate of APCNs. According to obtained results, these APCNs could be used as biomaterials for the controlled release of agrochemicals.
Electrospun Copolyamide Mats Modified by Functionalized Multiwall Carbon Nanotubes
Authors: Sobolciak Patrik , Tanvir Aisha , Popelka Anton , Spitalsky Zdeno , Mrlik Miroslav , Krupa Igor
Published: October 2018

In this article, we report the preparation and properties of electro‐conductive mats based on the commercial copolyamide (Vestamelt X1010) and multiwall carbon nanotubes functionalized by amino groups. Vestamelt X1010 is easily soluble in n‐propanol at room temperature up to a concentration of 18 wt%. This is a significant advantage of this system because n‐propanol is considered to be a safe and relatively environmentally friendly solvent compared with the organic solvents and acids frequently used for electrospinning of common synthetic polymers. The co‐polyamide nanofibers were modified by multiwall carbon nanotubes grafted by amino groups to enhance their electrical conductivity at low filler content. The percolation threshold was found to be 0.33 vol%. Some applications of these mats were demonstrated such as the capability for sensing a selected vapor (acetone) and for oil/water separation. It was shown that neat Vestamelt X1010 mats remove around 85 wt% of oil (100 ppm of vegetable oil dispersed in water), whereas the addition of 1 wt% of CNTs enhances this ability up to 95 wt%. POLYM. COMPOS., 40:E1451–E1460, 2019. © 2018 Society of Plastics Engineers
The relationship between vicarious experience, social persuasion, physiological state, and chemistry self‐efficacy: The role of mastery experience as a mediator
Authors: Capa‐Aydin Yesim , Uzuntiryaki‐Kondakci Esen , Ceylandag Rana
Published: October 2018

Using social cognitive theory as a theoretical framework, the current study examined the mediating role of mastery experience between other sources (vicarious experience, social persuasion, and physiological state) and chemistry self‐efficacy for cognitive skills, which can be defined as students’ beliefs in their capabilities to successfully perform intellectual operations in chemistry. Data were collected from 397 high school students through the High School Chemistry Self‐Efficacy Scale and Sources of Self‐Efficacy Scale. Results of structural equation modeling indicated that mastery experience and vicarious experience directly influenced chemistry self‐efficacy. In addition, a mediation effect of mastery experience was found for social persuasion and physiological state, while no mediation was found for vicarious experience. Overall, 50% of variance in chemistry self‐efficacy for cognitive skills is explained by, or predicted from, the direct and indirect influences of mastery experience.
Conformational Characterization and Classification of Intrinsically Disordered Proteins by Native Mass Spectrometry and Charge‐State Distribution Analysis
Authors: Santambrogio Carlo , Natalello Antonino , Brocca Stefania , Ponzini Erika , Grandori Rita
Published: October 2018

Intrinsically disordered proteins (IDPs) are systematically under‐represented in structural proteomics studies. Their structural characterization implies description of the dynamic conformational ensembles populated by these polymers in solution, posing major challenges to biophysical methods. “Native” MS (native‐MS) has emerged as a central tool in this field, conjugating the unique MS analytical power with structurally meaningful descriptors, like solvent‐accessible surface area (SASA) and collisional cross section (CCS). This review summarizes recently published papers comparing native‐MS and solution methods, with a focus on charge‐state‐distribution (CSD) analysis for IDP conformational analysis. The results point to substantial agreement, supporting structural interpretation of native‐MS spectra of IDPs. The discussion is integrated with data from our group on “synthetic” IDPs, obtained by reduction and alkylation of natively folded proteins, whose fold is stabilized by disulfide bridges. Finally, an MS‐based compaction index (CI) is introduced, evaluating SASA with reference to globular and fully disorder proteins. Such a parameter can be calculated for single conformers or the whole conformational ensemble, offering a continuous index for IDP comparison and classification.
Plectin is Required for Trans‐Endothelial Permeability: A Model of Plectin Dysfunction in Human Endothelial Cells After TNF‐α Treatment and Dengue Virus Infection
Authors: Suttitheptumrong Aroonroong , Rawarak Nantapon , Reamtong Onrapak , Boonnak Kobporn , Pattanakitsakul Sa‐nga
Published: October 2018

The clinical sign of dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) in humans is increased vascular permeability. Virus‐specific factors and host factors, including secreted cytokines and especially TNF‐α, are suggested as having roles in the pathogenesis of these conditions. Proteomic analysis with MS is performed in membrane fraction isolated from human endothelial cells (EA.hy926) upon DENV infection and TNF‐α treatment. In the 451 altered proteins that are identified, decreased plectin expression is revealed by Western blot analysis, while immunofluorescence staining (IFA) shows actin stress fiber rearrangement and decreased VE‐cadherin in treated EA.hy926 cells. In vitro vascular permeability assay was used to determine transepithelial electrical resistance (TEER) in EA.hy926 cells seeded on collagen‐coated Transwell inserts. The low level of TEER, the low expression of plectin and VE‐cadherin, and the unusual organization of actin stress fiber are found to be correlated with increased membrane permeability in DENV2 and TNF‐α‐treated EA.hy926 cells. Similar results are observed when using siRNA knockdown plectin in mock EA.hy926 cells. This study provides better understanding of the role that disruption of cytoskeleton linker protein plays in increased vascular permeability, and suggests these factors as major contributors to vascular leakage in DHF/DSS patients.
Me3SiBr/InCl3 catalyzed allylation of alcohols: Identifying the combined Lewis structure and investigating the reaction mechanism
Authors: Liu Changmei , Sang Shenglong , Chen Fei , Yan Yan , Zhang Cong , Huang Wei
Published: October 2018

The combined Lewis acid Me3SiBr/InCl3 shows unique performance in multireactions. The topology and catalytic properties of Me3SiBr/InCl3 were investigated by DFT method for clarifying the nature of chemical bonds and interactions. Quantum theory of atoms in molecules (QTAIM) analysis showed that the interaction between Me3Si‐halide and In‐trihalide mainly belongs to the closed‐shell interaction. Natural bond order of Br─In is 0.610 in INT_0 while natural bond order of Cl─In in INT_1 is only 0.081 at SMD‐ωB97XD/def2‐SVP level. The coupling reaction mechanism of alcohol and allyltrimethylsilane catalyzed by the complex of Me3SiBr/InCl3 was investigated with DFT method. The combined Lewis acid activates the hydroxyl group by strong coordination to silicone center, which leads to the generation of carbocation. Me3Si+ moiety from the combined Lewis acid is consumed and converts into the side product Me3SiOSiMe3. Furthermore, the reactant allyltrimethylsilane is introduced into the system to bring out the final product, and the complex Me3SiBr/InCl3 is reproduced at the same time. The combined Lewis acid Me3SiBr/InCl3 not only works as the catalyst for the reaction but also involves in the generation of side product.
Refractive Index Dispersion of Hexagonal Boron Nitride in the Visible and Near‐Infrared
Authors: Lee Seong‐Yeon , Jeong Tae‐Young , Jung Suyong , Yee Ki‐Ju
Published: October 2018

Hexagonal boron nitride (h‐BN) is being widely utilized as a platform for optical and electrical devices exploiting two‐dimensional layered materials. By analyzing transmission spectra of h‐BN flakes transferred onto quartz plates with the transfer‐matrix method, the refractive index of h‐BN is determined in the wavelength range from 450 to 1200 nm. The transmission spectra are reproduced by applying the single oscillator model of n(λ)2 = 1 + Aλ2/(λ2–λ02) as the wavelength‐dependent refractive index. Averaging over the parameters from different samples, the parameters of λ0 = 164.4 nm and A = 3.263 are obtained.
UltraMassExplorer: a browser‐based application for the evaluation of high‐resolution mass spectrometric data
Authors: Leefmann Tim , Frickenhaus Stephan , Koch Boris P.
Published: October 2018

Rationale

High‐resolution mass spectrometry (HRMS) with high sample throughput has become an important analytical tool for the analysis of highly complex samples and data processing has become a major challenge for the user community. Evaluating direct‐infusion HRMS data without automated tools for batch processing can be a time‐consuming step in the analytical pipeline. Therefore, we developed a new browser‐based software tool for processing HRMS data.

Methods

The software, named UltraMassExplorer (UME), was written in the R programming language using the shiny library to build the graphical user interface. The performance of the integrated formula library search algorithm was tested using HRMS data derived from analyses of up to 50 extracts of marine dissolved organic matter.

Results

The software supports the processing of lists of calibrated masses of neutral, protonated or deprotonated molecules, with masses of up to 700 Da and a mass accuracy <3 ppm. In the performance test, the number of assigned peaks per second increased with the number of submitted peaks and reached a maximum rate of 4745 assigned peaks per second.

Conclusions

UME offers a complete data evaluation pipeline comprising a fast molecular formula assignment algorithm allowing for the swift reanalysis of complete datasets, advanced filter functions and the export of data, metadata and publication‐quality graphics. Unique to UME is a fast and interactive connection between data and their visual representation. UME provides a new platform enabling an increased transparency, customization, documentation and comparability of datasets.
Robust vertex‐dependent H∞ and H2 estimation for stochastic linear systems
Authors: Gershon E. , Shaked U.
Published: October 2018

We consider linear continuous‐time systems with multiplicative noise and polytopic‐type parameter uncertainty, and we address the problems of H∞ and H2 filtering of these systems. These problems are solved by applying a vertex‐dependent Lyapunov function that considerably reduces the overdesign associated with the classical design that is based on a single Lyapunov function for the whole parameter range. A new approach of the Finsler lemma is used that decreases the overdesign entailed in the usual derivation of the robust estimation problem. The developed theory is also extended to the robust gain scheduling case where online measurement is used to improve the estimation. Two examples are given that demonstrate the tractability and applicability of the design methods.
Tunable Physicochemical and Bactericidal Activity of Multicarboxylic‐Acids‐Crosslinked Polyvinyl Alcohol Membrane for Food Packaging Applications
Authors: Suganthi Sanjeevamuthu , Mohanapriya Subramanian , Raj Vairamuthu , Kanaga Selvaraj , Dhandapani Ramamurthy , Vignesh Shanmugam , Kalyana Sundar Jeyaperumal
Published: October 2018

The present study demonstrates the role of multicarboxylic acids as crosslinkers to polyvinyl alcohol (PVA) films were fabricated by solution casting method for food packing applications. Effect of incorporating different carboxylic acids namely oxalic acid (OA), succinic acid (SA) and citric acid (CA) on physicochemical and bioactive properties of PVA were investigated in detail. The crystalline phase, optical absorptions and the functional group were analyzed through X‐Ray diffraction (XRD), UV‐Vis and Fourier Transform Infrared (FTIR) Spectroscopy. Thermal, microstructure and surface analysis were studied by Differential thermal analysis (TG/DTA) and Scanning Electron Microscope (SEM) analysis and the chief anti‐bacterial activity. The rheological study was carried out using precursor polymer solutions with different crosslinkers reveal that viscosity of PVA/CA solution is higher. Surface topography and roughness exert a strong influence on bactericidal properties of films as evidenced by Atomic Force Microscope (AFM) analysis. Among they studied films, PVA/CA exhibits higher bacterial inhibition efficiency mainly due to the ability of CA to alter local pH and cause an alteration in the permeability of microbial membrane by disrupting bacterial substrate transport. In addition to this food quality analysis results of microbial tests revealed an increase in the microbial shelf life of sliced carrot from 1 to 5 days for PVA/CA film compared to the control and commercial.
Alternative Biofuel Materials for Microbial Fuel Cells from Poplar Wood
Authors: Erensoy Ahmet , Çek Nurettin
Published: October 2018

In this study, biofuel properties of poplar wood materials rich in organic materials were investigated for microbial fuel cells. Therefore, in this study, investigates the chemical, biochemical properties with electrochemical performance of single chamber microbial fuel cell manufactured using poplar biomass materials, natural soil, graphite anode electrode and graphite cathode electrode. With the increase in the weight of the poplar tree in the microbial fuel cells, the power density increased. SEM, EDS, FTIR analyses showed that bacillus and coccus type bacteria in the natural structure of the soil act as the catalyst in the anode electrode. Poplar wood, electrodes and bacteria have served in harmony. According to experimental results, the maximum power reaches to 16.88 mW and microbial fuel cell successfully displays a maximum power density of 8555 mW/m2. All these results indicate that poplar wood may be appropriate biofuel sources for electrical energy generation as an effective environmentally microbial fuel cell technology.
Conformation Specific Binding of [Ru(phen)2(dppz)]2+ with Mono‐ and Cluster Arylamine‐DNA Adducts
Authors: Thangavel Nandhini , Ganesan Vaidyanathan V. , Nair Balachandran U.
Published: October 2018

The development of any probe to detect cluster adducts requires an in depth understanding on the binding affinity of probes to these adducts. In this context, we attempted to study the interaction of known DNA molecular switch [Ru(phen)2(dppz)]2+ with mono‐ and cluster DNA adducts in 16‐mer NarI sequence (5′‐CTCTCG1G2CG3CCATCAC‐3′) where guanine bases are modified with N‐acetyl‐2‐aminofluorene(AAF). Luminescence studies show that [Ru(phen)2(dppz)]2+ (phen: 1,10‐phenanthroline and dppz: dipyrido[3,2‐a:2′,3′‐c]phenazine) binds to AAF adduct at G1 and G3 which possesses minor‐groove(W) and stacked conformation(S) exhibit two fold enhancement while G2 with major groove B‐conformer exhibit 1.6 fold enhancement when compared to control. In diadducts, RuII binds to G2G3 AAF adduct lower than that of other two diadducts G1G3 and G1G2. With triadducts, phenazine moiety of RuII complex adopts canted geometry to the DNA due to the very unstable structure at the adducted site. From microscale thermophoretic data, the kd of RuII was determined and found to be consistent with luminescence data. The present study provides an overall insight of role of conformation of AAF structure embedded in different sequence context that dictates the sensitivity of the DNA molecular light switch, in turn, facilitates in developing highly efficient probe to distinguish these cluster adducts.
Synthesis of 7H‐Indolo[2,3‐c]quinolines by Chemoselective Suzuki Reaction Followed by a Ring‐Closing Two‐Fold Buchwald‐Hartwig Reaction of 3‐Bromo‐4‐iodoquinoline
Authors: Rivera Rodisnel Perdomo , Ehlers Peter , Rodríguez Eugenio Torres , Langer Peter
Published: October 2018

N‐functionalized 7H‐indolo[2,3‐c]quinolines have been synthesized by chemoselective Suzuki‐reaction followed by a ring‐closing two‐fold Buchwald‐Hartwig reaction. The developed methodology allows the application of various anilines, benzyl amines as well as aliphatic amines and led to corresponding products in high yields.
HClO4⋅SiO2‐Catalyzed Mechanochemical Protocol: An Effective, Economical and Eco‐friendly Preparation of N‐(tert‐butylsulfinyl)imines
Authors: Appa Rama Moorthy , Lakshmidevi Jangam , Prasad S. Siva , Naidu Bandameeda Ramesh , Narasimhulu Manchala , Venkateswarlu Katta
Published: October 2018

The imines of Ellman's tert‐butylsulfinamides have become one of the elementary substrates for the construction of chiral precursors and complex organic molecules. This article reports a mechanochemical access to imines of chiral tert‐butylsulfinamides with a variety of aldehydes using solid acid catalyst, perchloric acid‐silica (HClO4⋅SiO2) at innocuous reaction environs. The conversion can be carried out at ambient temperature under solvent and metal‐free conditions by (hand) grinding the contents in a mortar at open‐air. The current protocol is highly economical, allows large‐scale preparation, offers a very good to nearly quantitative yields of imines in short reaction times with no product racemization and doesn′t necessitate the moisture‐free conditions.