bluuebunny/crossref_metadata_2025 huggingface dataset:
An Asymmetrical Glycerol Diether Bolalipid with Protonable Phosphodimethylethanolamine Headgroup: The Impact of pH on Aggregation Behavior and Miscibility with DPPC
Authors: Markowski Thomas , Müller Sindy , Dobner Bodo , Meister Annette , Blume Alfred , Drescher Simon
Published: November 2017

Investigations regarding the self-assembly of (bola)phospholipids in aqueous media are crucial to understand the complex relationship between chemical structure of lipids and the shape and size of their aggregates in water. Here, we introduce a new asymmetrical glycerol diether bolaphospholipid, the compound Me2PE-Gly(2C16)C32-OH. This bolalipid contains a long (C32) ω-hydroxy alkyl chain bond to glycerol in the sn-3 position, a C16 alkyl chain at the sn-2 position, and a protonable phosphodimethylethanolamine (Me2PE) headgroup at the sn-1 position of the glycerol. The aggregation behavior of this bolalipid was studied as a function of temperature and pH using transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. We show that this bolalipid aggregates into condensed lamellar sheets in acidic milieu and in large sheet-like aggregates at neutral pH-value. By contrast, at a pH-value of 10, where the Me2PE headgroup is only partially protonated, small lipid disks with diameter 50–100 nm were additionally found. Moreover, the miscibility of this asymmetrical bolalipid with the bilayer-forming phosphatidylcholine DPPC was investigated by means of DSC and TEM. The incorporation of bolalipids into phospholipid membranes could result in stabilized liposomes applicable for drug delivery purposes. We show that mixtures of DPPC and Me2PE-Gly(2C16)C32-OH form large lamellar aggregates at pH of 5, 7, and 10. However, closed lipid vesicles (liposomes) with an increased thermal stability were not found.
Restoration of Impaired Metabolic Energy Balance (ATP Pool) and Tube Formation Potential of Endothelial Cells under “high glucose”, Diabetic Conditions by the Bioinorganic Polymer Polyphosphate
Authors: Wang Xiaohong , Ackermann Maximilian , Neufurth Meik , Wang Shunfeng , Li Qiang , Feng Qingling , Schröder Heinz , Müller Werner
Published: November 2017

Micro-vascularization is a fast, energy-dependent process that is compromised by elevated glucose concentrations such as in diabetes mellitus disease. Here, we studied the effect of the physiological bioinorganic polymer, polyphosphate (polyP), on the reduced ATP content and impaired function of endothelial cells cultivated under “high glucose” (35 mM diabetes mellitus conditions) concentrations. This high-energy biopolymer has been shown to provide a source of metabolic energy, stored in its phosphoanhydride bonds. We show that exposure of human umbilical vein endothelial cells (HUVEC cells) to “high glucose” levels results in reduced cell viability, increased apoptotic cell death, and a decline in intracellular ATP level. As a consequence, the ability of HUVEC cells to form tube-like structures in the in vitro cell tube formation assay was almost completely abolished under “high glucose” conditions. Those cells were grown onto a physiological collagen scaffold (collagen/basement membrane extract). We demonstrate that these adverse effects of increased glucose levels can be reversed by administration of polyP to almost normal values. Using Na-polyP, complexed in a stoichiometric (molar) ratio to Ca2+ ions and in the physiological concentration range between 30 and 300 µM, an almost complete restoration of the reduced ATP pool of cells exposed to “high glucose” was found, as well as a normalization of the number of apoptotic cells and energy-dependent tube formation. It is concluded that the adverse effects on endothelial cells caused by the metabolic energy imbalance at elevated glucose concentrations can be counterbalanced by polyP, potentially opening new strategies for treatment of the micro-vascular complications in diabetic patients.
A Cationic Smart Copolymer for DNA Binding
Authors: Ribeiro Tânia , Santiago Ana , Gaspar Martinho Jose , Farinha Jose
Published: November 2017

A new block copolymer with a temperature-responsive block and a cationic block was prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization, with good control of its size and composition. The first block is composed by di(ethylene glycol) methyl ether methacrylate (DEGMA) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA), with the ratio DEGMA/OEGMA being used to choose the volume phase transition temperature of the polymer in water, tunable from ca. 25 to above 90 °C. The second block, of trimethyl-2-methacroyloxyethylammonium chloride (TMEC), is positively charged at physiological pH values and is used for DNA binding. The coacervate complexes between the block copolymer and a model single strand DNA are characterized by fluorescence correlation spectroscopy and fluorescence spectroscopy. The new materials offer good prospects for biomedical application, for example in controlled gene delivery.
Dynamics of Dual Scale-Free Polymer Networks
Authors: Galiceanu Mircea , Tota de Carvalho Luan , Mülken Oliver , Dolgushev Maxim
Published: November 2017

We focus on macromolecules which are modeled as sequentially growing dual scale-free networks. The dual networks are built by replacing star-like units of the primal treelike scale-free networks through rings, which are then transformed in a small-world manner up to the complete graphs. In this respect, the parameter γ describing the degree distribution in the primal treelike scale-free networks regulates the size of the dual units. The transition towards the networks of complete graphs is controlled by the probability p of adding a link between non-neighboring nodes of the same initial ring. The relaxation dynamics of the polymer networks is studied in the framework of generalized Gaussian structures by using the full eigenvalue spectrum of the Laplacian matrix. The dynamical quantities on which we focus here are the averaged monomer displacement and the mechanical relaxation moduli. For several intermediate values of the parameters’ set ( γ , p ) , we encounter for these dynamical properties regions of constant in-between slope.
A Strategy of Rapid Extraction of Built-Up Area Using Multi-Seasonal Landsat-8 Thermal Infrared Band 10 Images
Authors: Zhang Ping , Sun Qiangqiang , Liu Ming , Li Jing , Sun Danfeng
Published: November 2017

Recently, studies have focused more attention on surface feature extraction using thermal infrared remote sensing (TIRS) as supplementary materials. Innovatively, in this paper, using three-date (winter, early spring, and end of spring) TIRS Band 10 images of Landsat-8, we proposed an empirical normalized difference of a seasonal brightness temperature index (NDSTI) for enhancing a built-up area based on the contrast heat emission seasonal response of a built-up area to solar radiation, and adopted a decision tree classification method for the rapidly accurate extraction of the built-up area. Four study areas, including one major experimental study area (Tangshan) and three verification areas (Minqin, Laizhou, and Yugan) in different climate zones, respectively, were used to empirically establish the overall strategy system, then we specified constrained conditions of this strategy. Moreover, we compared the NDSTI to the current built-up indices, respectively, for extracting the built-up area. The results showed that (1) the new index (NDSTI) exploited the seasonal thermal characteristic variation between the built-up area and other covers in the time series analysis, helping achieve more accurate built-up area extraction than other spectral indices; (2) this strategy could effectively realize rapid built-up area extraction with generally satisfied overall accuracy (over 80%), and was especially excellent in Tangshan and Laizhou; however, (3) it may be constrained by climate patterns and other surface characteristics, which need to be improved from the view of the results of Minqin and Yugan. In summary, the method developed in this study has the potential and advantage to extract the built-up area rapidly from the multi-seasonal thermal infrared remote sensing data. It could be an operative tool for long-term monitoring of built-up areas efficiently and for more applications of thermal infrared images in the future.
Optimizing the Timing of Unmanned Aerial Vehicle Image Acquisition for Applied Mapping of Woody Vegetation Species Using Feature Selection
Authors: Weil Gilad , Lensky Itamar , Resheff Yehezkel , Levin Noam
Published: November 2017

Most recent studies relating to the classification of vegetation species on the individual level use cutting-edge sensors and follow a data-driven approach, aimed at maximizing classification accuracy within a relatively small allocated area of optimal conditions. However, this approach does not incorporate cost-benefit considerations or the ability of applying the chosen methodology for applied mapping over larger areas with higher natural heterogeneity. In this study, we present a phenology-based cost-effective approach for optimizing the number and timing of unmanned aerial vehicle (UAV) imagery acquisition, based on a priori near-surface observations. A ground-placed camera was used in order to generate annual time series of nine spectral indices and three color conversions (red, green and blue to hue, saturation and value) in four different East Mediterranean sites that represent different environmental conditions. After outliers’ removal, the time series dataset represented 1852 individuals of 12 common vegetation species and annual herbaceous patches. A feature selection process was used for identifying the optimal dates for species classification in every site. The feature selection can be designed for various objectives, e.g., optimization of overall classification, discrimination between two species, or discrimination of one species from all others. In order to evaluate the a priori findings, a UAV was flown for acquiring five overhead multiband orthomosaics (five bands in the visible-near infrared range based on the five optimal dates identified in the feature selection of the near-surface time series of the previous year. An object-based classification methodology was used for the discrimination of 976 individuals of nine species and annual herbaceous patches in the UAV imagery, and resulted in an average overall accuracy of 85% and an average Kappa coefficient of 0.82. This cost-effective approach has high potential for detailed vegetation mapping, regarding the accessibility of UAV-produced time series, compared to hyper-spectral imagery with high spatial resolution which is more expensive and involves great difficulties in implementation over large areas.
A Ratiometric Fluorescent Sensor for Cd2+ Based on Internal Charge Transfer
Authors: Cheng Dandan , Liu Xingliang , Xie Yadian , Lv Haitang , Wang Zhaoqian , Yang Hongzhi , Han Aixia , Yang Xiaomei , Zang Ling
Published: November 2017

This work reports on a novel fluorescent sensor 1 for Cd2+ ion based on the fluorophore of tetramethyl substituted bis(difluoroboron)-1,2-bis[(1H-pyrrol-2-yl)methylene]hydrazine (Me4BOPHY), which is modified with an electron donor moiety of N,N-bis(pyridin-2-ylmethyl)benzenamine. Sensor 1 has absorption and emission in visible region, at 550 nm and 675 nm, respectively. The long wavelength spectral response makes it easier to fabricate the fluorescence detector. The sensor mechanism is based on the tunable internal charge transfer (ICT) transition of molecule 1. Binding of Cd2+ ion quenches the ICT transition, but turns on the π − π transition of the fluorophore, thus enabling ratiometric fluorescence sensing. The limit of detection (LOD) was projected down to 0.77 ppb, which is far below the safety value (3 ppb) set for drinking water by World Health Organization. The sensor also demonstrates a high selectivity towards Cd2+ in comparison to other interferent metal ions.
An Energy Efficient Adaptive Sampling Algorithm in a Sensor Network for Automated Water Quality Monitoring
Authors: Shu Tongxin , Xia Min , Chen Jiahong , De Silva Clarence
Published: November 2017

Power management is crucial in the monitoring of a remote environment, especially when long-term monitoring is needed. Renewable energy sources such as solar and wind may be harvested to sustain a monitoring system. However, without proper power management, equipment within the monitoring system may become nonfunctional and, as a consequence, the data or events captured during the monitoring process will become inaccurate as well. This paper develops and applies a novel adaptive sampling algorithm for power management in the automated monitoring of the quality of water in an extensive and remote aquatic environment. Based on the data collected on line using sensor nodes, a data-driven adaptive sampling algorithm (DDASA) is developed for improving the power efficiency while ensuring the accuracy of sampled data. The developed algorithm is evaluated using two distinct key parameters, which are dissolved oxygen (DO) and turbidity. It is found that by dynamically changing the sampling frequency, the battery lifetime can be effectively prolonged while maintaining a required level of sampling accuracy. According to the simulation results, compared to a fixed sampling rate, approximately 30.66% of the battery energy can be saved for three months of continuous water quality monitoring. Using the same dataset to compare with a traditional adaptive sampling algorithm (ASA), while achieving around the same Normalized Mean Error (NME), DDASA is superior in saving 5.31% more battery energy.
Detonation Velocity Measurement with Chirped Fiber Bragg Grating
Authors: Wei Peng , Lang Hao , Liu Taolin , Xia Dong
Published: November 2017

Detonation velocity is an important parameter for explosive, and it is crucial for many fields such as dynamic chemistry burn models, detonation propagation prediction, explosive performance estimation, and so on. Dual-channel detonation velocity measurement method and system are described. The CFBG sensors are pasted both on the surface and in the center of the explosive cylinder. The length of CFBG sensors is measured via the hot-tip probe method. The light intensity reflected from the CFBG sensors attached to the explosive is transformed to voltage, and the voltage–time is then measured with the oscilloscope. According to the five experiments results, the relative standard uncertainty of detonation velocity is below 1%.
A Real-Time Smooth Weighted Data Fusion Algorithm for Greenhouse Sensing Based on Wireless Sensor Networks
Authors: Zou Tengyue , Wang Yuanxia , Wang Mengyi , Lin Shouying
Published: November 2017

Wireless sensor networks are widely used to acquire environmental parameters to support agricultural production. However, data variation and noise caused by actuators often produce complex measurement conditions. These factors can lead to nonconformity in reporting samples from different nodes and cause errors when making a final decision. Data fusion is well suited to reduce the influence of actuator-based noise and improve automation accuracy. A key step is to identify the sensor nodes disturbed by actuator noise and reduce their degree of participation in the data fusion results. A smoothing value is introduced and a searching method based on Prim’s algorithm is designed to help obtain stable sensing data. A voting mechanism with dynamic weights is then proposed to obtain the data fusion result. The dynamic weighting process can sharply reduce the influence of actuator noise in data fusion and gradually condition the data to normal levels over time. To shorten the data fusion time in large networks, an acceleration method with prediction is also presented to reduce the data collection time. A real-time system is implemented on STMicroelectronics STM32F103 and NORDIC nRF24L01 platforms and the experimental results verify the improvement provided by these new algorithms.
Single-Shot Dense Depth Sensing with Color Sequence Coded Fringe Pattern
Authors: Li Fu , Zhang Baoyu , Shi Guangming , Niu Yi , Li Ruodai , Yang Lili , Xie Xuemei
Published: November 2017

A single-shot structured light method is widely used to acquire dense and accurate depth maps for dynamic scenes. In this paper, we propose a color sequence coded fringe depth sensing method. To overcome the phase unwrapping problem encountered in phase-based methods, the color-coded sequence information is embedded into the phase information. We adopt the color-encoded De Bruijn sequence to denote the period of the phase information and assign the sequence into two channels of the pattern, while the third channel is used to code the phase information. Benefiting from this coding strategy, the phase information distributed in multiple channels can improve the quality of the phase intensity by channel overlay, which results in precise phase estimation. Meanwhile, the wrapped phase period assists the sequence decoding to obtain a precise period order. To evaluate the performance of the proposed method, an experimental platform is established. Quantitative and qualitative experiments demonstrate that the proposed method generates a higher precision depth, as compared to a Kinect and larger resolution ToF (Time of Flight) camera.
Effect of Irrigation Schemes on Forage Yield, Water Use Efficiency, and Nutrients in Artificial Grassland under Arid Conditions
Authors: Tian Yuhong , Liu Yiqing , Jin Jianjun
Published: November 2017

Artificial grasslands are effective solutions to problems with grassland degradation. Water scarcity is an important limitation for grassland production in arid regions. In this study, we carried out comparison experiments to assess the impacts of irrigation schemes on forage yield, water use efficiency, and nutrients in the single and mixed sowing ways of Medicago sativa L. and Agropyron cristatum in different stages in artificial grassland. Results indicated that deficit irrigation can increase forage yields of M. sativa and A. cristatum in most growth stages and sowing treatments. Heavy deficit irrigation or even no irrigation had the greatest potential to increase forage yields of both species in the squaring stage and instantaneous water-use efficiency (WUEI) in all growth stages. They can also significantly increase the nutritional level of M. sativa using a mixed sowing method. In June and September, only irrigating to near field capacity (T1) can increase the long-term water-use efficiency (WUEL) of both species. We suggest irrigating with water to near field capacity in June, and applying deficit irrigation in July and August. Deficit irrigation is an effective water management technique to both save water and increase forage quality in arid areas.
Deep Learning-Based Iris Segmentation for Iris Recognition in Visible Light Environment
Authors: Arsalan Muhammad , Hong Hyung , Naqvi Rizwan , Lee Min , Kim Min , Kim Dong , Kim Chan , Park Kang
Published: November 2017

Existing iris recognition systems are heavily dependent on specific conditions, such as the distance of image acquisition and the stop-and-stare environment, which require significant user cooperation. In environments where user cooperation is not guaranteed, prevailing segmentation schemes of the iris region are confronted with many problems, such as heavy occlusion of eyelashes, invalid off-axis rotations, motion blurs, and non-regular reflections in the eye area. In addition, iris recognition based on visible light environment has been investigated to avoid the use of additional near-infrared (NIR) light camera and NIR illuminator, which increased the difficulty of segmenting the iris region accurately owing to the environmental noise of visible light. To address these issues; this study proposes a two-stage iris segmentation scheme based on convolutional neural network (CNN); which is capable of accurate iris segmentation in severely noisy environments of iris recognition by visible light camera sensor. In the experiment; the noisy iris challenge evaluation part-II (NICE-II) training database (selected from the UBIRIS.v2 database) and mobile iris challenge evaluation (MICHE) dataset were used. Experimental results showed that our method outperformed the existing segmentation methods.
The Selection of Wagons for the Internal Transport of a Logistics Company: A Novel Approach Based on Rough BWM and Rough SAW Methods
Authors: Stević Željko , Pamučar Dragan , Kazimieras Zavadskas Edmundas , Ćirović Goran , Prentkovskis Olegas
Published: November 2017

The rationalization of logistics activities and processes is very important in the business and efficiency of every company. In this respect, transportation as a subsystem of logistics, whether internal or external, is potentially a huge area for achieving significant savings. In this paper, the emphasis is placed upon the internal transport logistics of a paper manufacturing company. It is necessary to rationalize the movement of vehicles in the company’s internal transport, that is, for the majority of the transport to be transferred to rail transport, because the company already has an industrial track installed in its premises. To do this, it is necessary to purchase at least two used wagons. The problem is formulated as a multi-criteria decision model with eight criteria and eight alternatives. The paper presents a new approach based on a combination of the Simple Additive Weighting (SAW) method and rough numbers, which is used for ranking the potential solutions and selecting the most suitable one. The rough Best–Worst Method (BWM) was used to determine the weight values of the criteria. The results obtained using a combination of these two methods in their rough form were verified by means of a sensitivity analysis consisting of a change in the weight criteria and comparison with the following methods in their conventional and rough forms: the Analytic Hierarchy Process (AHP), Technique for Ordering Preference by Similarity to Ideal Solution (TOPSIS) and MultiAttributive Border Approximation area Comparison (MABAC). The results show very high stability of the model and ranks that are the same or similar in different scenarios.
TGF-β1/Smad3 Signaling Pathway Mediates T-2 Toxin-Induced Decrease of Type II Collagen in Cultured Rat Chondrocytes
Authors: Li Yang , Zou Ning , Wang Jing , Wang Ke-Wei , Li Fu-Yuan , Chen Fu-Xun , Sun Bing-Yu , Sun Dian-Jun
Published: November 2017

T-2 toxin can cause damage to the articular cartilage, but the molecular mechanism remains unclear. By employing the culture of rat chondrocytes, we investigated the effect of the TGF-β1/Smad3 signaling pathway on the damage to chondrocytes induced by T-2 toxin. It was found that T-2 toxin could reduce cell viability and increased the number of apoptotic cells when compared with the control group. After the addition of the T-2 toxin, the production of type II collagen was reduced at mRNA and protein levels, while the levels of TGF-β1, Smad3, ALK5, and MMP13 were upregulated. The production of the P-Smad3 protein was also increased. Inhibitors of TGF-β1 and Smad3 were able to reverse the effect of the T-2 toxin on the protein level of above-mentioned signaling molecules. The T-2 toxin could promote the level of MMP13 via the stimulation of TGF-β1 signaling in chondrocytes, resulting in the downregulation of type II collagen and chondrocyte damage. Smad3 may be involved in the degradation of type II collagen, but the Smad3 has no connection with the regulation of MMP13 level. This study provides a new clue to elucidate the mechanism of T-2 toxin-induced chondrocyte damage.
The Impact of Demographic Factors, Beliefs, and Social Influences on Residential Water Consumption and Implications for Non-Price Policies in Urban India
Authors: Ramsey Elizabeth , Berglund Emily , Goyal Rohit
Published: November 2017

In rapidly growing urban areas in India and the developing world, water demands typically exceed supply. While local governments may implement management programs to reduce demand for freshwater, water savings are dependent on the conservation behaviors of individuals. A household survey is presented here to examine residential water end uses and conservation behaviors in Jaipur, India. The survey explores end uses, engagement in conservation behaviors, and the influence of demographic factors, water sources, beliefs about water, and social pressures on these behaviors are tested. The survey was conducted at 248 households, including 29 households in the slums. Our study finds that while the majority of participants recognize the importance of water conservation, they do not necessarily conserve water themselves. Households report engaging most frequently in water-conservation behaviors that require little effort or financial investment. Multivariate analysis of variance (MANOVA) results and subsequent pairwise comparisons indicate higher incomes, longer water-supply durations, and the belief that droughts are preventable are positively correlated with overall amenability to adoption of water-conservation behaviors and technology. Binomial logistic regression analysis indicates that being in the age group 26–35, having higher income, and giving a neutral response about the responsibility of the government to provide relief during a drought were all predictors of the installation of dual-flush (DF) toilets. Education levels and water awareness were found to have no correlation with conservation behaviors or amenability to conservation technology adoption. Results are applied to examine their possible implications from a demand-management perspective and provide suggestions for further research and policy decisions.
Statistical and Fractal Approaches on Long Time-Series to Surface-Water/Groundwater Relationship Assessment: A Central Italy Alluvial Plain Case Study
Authors: Chiaudani Alessandro , Di Curzio Diego , Palmucci William , Pasculli Antonio , Polemio Maurizio , Rusi Sergio
Published: November 2017

In this research, univariate and bivariate statistical methods were applied to rainfall, river and piezometric level datasets belonging to 24-year time series (1986–2009). These methods, which often are used to understand the effects of precipitation on rivers and karstic springs discharge, have been used to assess piezometric level response to rainfall and river level fluctuations in a porous aquifer. A rain gauge, a river level gauge and three wells, located in Central Italy along the lower Pescara River valley in correspondence of its important alluvial aquifer, provided the data. Statistical analysis has been used within a known hydrogeological framework, which has been refined by mean of a photo-interpretation and a GPS survey. Water–groundwater relationships were identified following the autocorrelation and cross-correlation analyses. Spectral analysis and mono-fractal features of time series were assessed to provide information on multi-year variability, data distributions, their fractal dimension and the distribution return time within the historical time series. The statistical–mathematical results were interpreted through fieldwork that identified distinct groundwater flowpaths within the aquifer and enabled the implementation of a conceptual model, improving the knowledge on water resources management tools.
Risk of and Fatality from Acute Pancreatitis in Long-Term Hemodialysis and Peritoneal Dialysis Patients
Authors: Wang I-Kuan , Lai Shih-Wei , Lai Hsueh-Chou , Lin Cheng-Li , Yen Tzung-Hai , Chou Che-Yi , Chang Chiz-Tzung , Huang Chiu-Ching , Sung Fung-Chang
Published: November 2017

Background

This study was conducted to evaluate the risk of developing acute pancreatitis (AP) and the fatality from AP in hemodialysis (HD) and peritoneal dialysis (PD) patients, using the claims data of Taiwan National Health Insurance.

Methods

From patients with newly diagnosed end-stage renal disease (ESRD) in 2000–2010, we identified a PD cohort ( N = 9,766), a HD cohort ( N = 18,841), and a control cohort ( N = 114,386) matched by sex, age, and the diagnosis year of the PD cohort. We also established another 2 cohorts with 9,744 PD patients and 9,744 propensity score-matched HD patients. The incident AP and fatality from AP were evaluated for all cohorts by the end of 2011.

Results

The adjusted hazard ratios (HRs) of acute pancreatitis were 5.68 (95% confidence interval [CI] = 5.05 – 6.39), 4.91 (95% CI = 4.32 – 5.59), and 7.47 (95% CI = 6.48 – 8.62) in the all dialysis, HD, and PD patients, compared with the controls, respectively. Peritoneal dialysis patients had an adjusted HR of 1.41 (95% CI = 1.21 – 1.65) for AP, compared with propensity score-matched HD patients. Peritoneal dialysis patients under icodextrin treatment had a lower incidence of AP than those without the treatment, with an adjusted HR of 0.59 (95% CI = 0.47 – 0.73). There was no significant difference in the 30-day mortality from AP between HD and PD patients.

Conclusions

Peritoneal dialysis patients were at a higher risk of developing AP than HD patients. Icodextrin solution could reduce the risk of developing AP in PD patients.
Numerical investigation of the tribological performance of micro-dimple textured surfaces under hydrodynamic lubrication
Authors: Li Kangmei , Jing Dalei , Hu Jun , Ding Xiaohong , Yao Zhenqiang
Published: November 2017

Surface texturing is an important approach for controlling the tribological behavior of friction pairs used in mechanical and biological engineering. In this study, by utilizing the method of three-dimensional computational fluid dynamics (CFD) simulation, the lubrication model of a friction pair with micro-dimple array was established based on the Navier–Stokes equations. The typical pressure distribution of the lubricant film was analyzed. It was found that a positive hydrodynamic pressure is generated in the convergent part of the micro-dimple, while a negative hydrodynamic pressure is generated in the divergent part. With suitable parameters, the total integration of the pressure is positive, which can increase the load-carrying capacity of a friction pair. The effects of the micro-dimple parameters as well as fluid properties on tribological performance were investigated. It was concluded that under the condition of hydrodynamic lubrication, the main mechanism for the improvement in the tribological performance is the combined effects of wedging and recirculation. Within the range of parameters investigated in this study, the optimum texture density is 13%, while the optimum aspect ratio varies with the Reynolds number. For a given Reynolds number, there exists a combination of texture density and aspect ratio at which the optimum tribological performance could be obtained. Conclusions from this study could be helpful for the design of texture parameters in mechanical friction components and even in artificial joints.
Solvent-free copper-catalyzed click chemistry for the synthesis of N-heterocyclic hybrids based on quinoline and 1,2,3-triazole
Authors: Tireli Martina , Maračić Silvija , Lukin Stipe , Kulcsár Marina Juribašić , Žilić Dijana , Cetina Mario , Halasz Ivan , Raić-Malić Silvana , Užarević Krunoslav
Published: November 2017

Copper-catalyzed mechanochemical click reactions using Cu(II), Cu(I) and Cu(0) catalysts have been successfully implemented to provide novel 6-phenyl-2-(trifluoromethyl)quinolines with a phenyl-1,2,3-triazole moiety at O-4 of the quinoline core. Milling procedures proved to be significantly more efficient than the corresponding solution reactions, with up to a 15-fold gain in yield. Efficiency of both solution and milling procedures depended on the p-substituent in the azide reactant, resulting in H < Cl < Br < I reactivity bias. Solid-state catalysis using Cu(II) and Cu(I) catalysts entailed the direct involvement of the copper species in the reaction and generation of highly luminescent compounds which hindered in situ monitoring by Raman spectroscopy. However, in situ monitoring of the milling processes was enabled by using Cu(0) catalysts in the form of brass milling media which offered a direct insight into the reaction pathway of mechanochemical CuAAC reactions, indicating that the catalysis is most likely conducted on the surface of milling balls. Electron spin resonance spectroscopy was used to determine the oxidation and spin states of the respective copper catalysts in bulk products obtained by milling procedures.
Correlation between Angular Widths of CMEs and Characteristics of Their Source Regions
Authors: Zhao X. H. , Feng X. S. , Feng H. Q. , Li Z.
Published: November 2017

The angular width of a coronal mass ejection (CME) is an important factor in determining whether the corresponding interplanetary CME (ICME) and its preceding shock will reach Earth. However, there have been very few studies of the decisive factors of the CME’s angular width. In this study, we use the three-dimensional (3D) angular width of CMEs obtained from the Graduated Cylindrical Shell model based on observations of Solar Terrestrial Relations Observatory (STEREO) to study the relations between the CME’s 3D width and characteristics of the CME’s source region. We find that for the CMEs produced by active regions (ARs), the CME width has some correlations with the AR’s area and flux, but these correlations are not strong. The magnetic flux contained in the CME seems to come from only part of the AR’s total flux. For the CMEs produced by flare regions, the correlations between the CME angular width and the flare region’s area and flux are strong. The magnetic flux within those CMEs seems to come from the whole flare region or even from a larger region than the flare. Our findings show that the CME’s 3D angular width can be generally estimated based on observations of Solar Dynamics Observatory for the CME’s source region instead of the observations from coronagraphs on board the Solar and Heliospheric Observatory andSTEREO if the two foot points of the CME stay in the same places with no expansion of the CME in the transverse direction until reaching Earth.
Two-fluid Numerical Simulations of Solar Spicules
Authors: Kuźma Błażej , Murawski Kris , Kayshap Pradeep , Wójcik Darek , Srivastava Abhishek Kumar , Dwivedi Bhola N.
Published: November 2017

We aim to study the formation and evolution of solar spicules by means of numerical simulations of the solar atmosphere. With the use of newly developed JOANNA code, we numerically solve two-fluid (for ions + electrons and neutrals) equations in 2D Cartesian geometry. We follow the evolution of a spicule triggered by the time-dependent signal in ion and neutral components of gas pressure launched in the upper chromosphere. We use the potential magnetic field, which evolves self-consistently, but mainly plays a passive role in the dynamics. Our numerical results reveal that the signal is steepened into a shock that propagates upward into the corona. The chromospheric cold and dense plasma lags behind this shock and rises into the corona with a mean speed of 20–25 km s−1. The formed spicule exhibits the upflow/downfall of plasma during its total lifetime of around 3–4 minutes, and it follows the typical characteristics of a classical spicule, which is modeled by magnetohydrodynamics. The simulated spicule consists of a dense and cold core that is dominated by neutrals. The general dynamics of ion and neutral spicules are very similar to each other. Minor differences in those dynamics result in different widths of both spicules with increasing rarefaction of the ion spicule in time.
The Emergence of the Infrared Transient VVV-WIT-06*
Authors: Minniti D. , Saito R. K. , Forster F. , Pignata G. , Ivanov V. D. , Lucas P. W. , Beamin J. C. , Borissova J. , Catelan M. , Gonzalez O. A. , Hempel M. , Hsiao E. , Kurtev R. , Majaess D. , Masetti N. , Morrell N. I. , Phillips M. M. , Pullen J. B. , Rejkuba M. , Smith L. , Surot F. , Valenti E. , Zoccali M.
Published: November 2017

We report the discovery of an enigmatic large-amplitude (

mag) transient event in near-IR data obtained by the VISTA Variables in the Via Lactea (VVV) ESO Public Survey. The object (designated VVV-WIT-06) is located at R.A. = 17:07:18.917, decl. = −39:06:26.45 (J2000), corresponding to Galactic coordinates l = 347.14539, b = 0.88522. It exhibits a clear eruption, peaking at Ks = 9 mag during 2013 July and fading to

in 2017. Our late near-IR spectra show post-outburst emission lines, including some broad emission lines (upward of

km s−1). We estimate a total extinction of

mag in the surrounding field, and no progenitor was observed in ZYJHKs images obtained during 2010–2012 (down to

mag). Subsequent deep near-IR imaging and spectroscopy, in concert with the available multiband photometry, indicate that VVV-WIT-06 may be either: (i) the closest Type I SN observed in about 400 years, (ii) an exotic high-amplitude nova that would extend the known realm of such objects, or (iii) a stellar merger. In all of these cases, VVV-WIT-06 is a fascinating and curious astrophysical target under any of the scenarios considered.
New VVV Survey Globular Cluster Candidates in the Milky Way Bulge*
Authors: Minniti Dante , Geisler Douglas , Alonso-García Javier , Palma Tali , Beamín Juan Carlos , Borissova Jura , Catelan Marcio , Clariá Juan J. , Cohen Roger E. , Ramos Rodrigo Contreras , Dias Bruno , Fernández-Trincado Jose G. , Gómez Matías , Hempel Maren , Ivanov Valentin D. , Kurtev Radostin , Lucas Phillip W. , Moni-Bidin Christian , Pullen Joyce , Alegría Sebastian Ramírez , Saito Roberto K. , Valenti Elena
Published: November 2017

It is likely that a number of Galactic globular clusters remain to be discovered, especially toward the Galactic bulge. High stellar density combined with high and differential interstellar reddening are the two major problems for finding globular clusters located toward the bulge. We use the deep near-IR photometry of the VISTA Variables in the Vía Láctea (VVV) Survey to search for globular clusters projected toward the Galactic bulge, and hereby report the discovery of 22 new candidate globular clusters. These objects, detected as high density regions in our maps of bulge red giants, are confirmed as globular cluster candidates by their color–magnitude diagrams. We provide their coordinates as well as their near-IR color–magnitude diagrams, from which some basic parameters are derived, such as reddenings and heliocentric distances. The color–magnitude diagrams reveal well defined red giant branches in all cases, often including a prominent red clump. The new globular cluster candidates exhibit a variety of extinctions (0.06 < A
Ks < 2.77) and distances (5.3 < D < 9.5 kpc). We also classify the globular cluster candidates into 10 metal-poor and 12 metal-rich clusters, based on the comparison of their color–magnitude diagrams with those of known globular clusters also observed by the VVV Survey. Finally, we argue that the census for Galactic globular clusters still remains incomplete, and that many more candidate globular clusters (particularly the low luminosity ones) await to be found and studied in detail in the central regions of the Milky Way.
Association of vitamin D binding protein polymorphisms with response to therapy in Egyptian chronic hepatitis C patients
Authors: Kamel Ahmed Mohamed , Farid Samar Farghali , Attia Ahmed Sherif , El. Raziky Maissa
Published: November 2017

Introduction: Vitamin D binding protein (VDBP) is a potential modulator of immune response and is associated with clinical progression of many diseases. Our aim was to assess influence of baseline 25-hydroxyvitamin D levels and VDBP single nucleotide polymorphisms (SNPs), rs4588 (C > A) and rs7041 (G > T), on baseline clinical parameters and response to interferon based therapy in chronic hepatitis C patients in Egypt.

Methodology: Genotyping was performed by RFLP (Restriction Fragment Length Polymorphism) in 112 treatment naïve hepatitis C patients and 50 healthy controls. Vitamin D levels were assessed by ELISA. HCV RNA quantification was performed by PCR to assess therapy outcome.

Results: Patients with VDBP WT+ diplotype (3 or 4 VDBP major alleles) had higher viral response rates at weeks 12, 48, and 72 (p = 0.046, 0.034 and 0.029, respectively) and lower base line viral load (p = 0.016). Multivariate logistic regression identified VDBP WT+ diplotype as an independent predictor of sustained viral response (SVR; p = 0.014, RR = 4.716, 95% CI = 1.371 – 16.609). Interestingly, WT- diplotype (less than 3 VDBP major alleles) was associated with significant liver fibrosis (p = 0.045).

Conclusions: VDBP WT+ diplotype is associated with lower baseline viral load and better therapy outcome in HCV treatment naïve patients. The rs4588 genotype is associated with SVR in the Egyptian population.
Human immunodeficiency virus prevalence and risk determinants among people who inject drugs in the Republic of Georgia
Authors: Shengelia Natia , Chikovani Ivdity , Sulaberidze Lela
Published: November 2017

Introduction: In Georgia as in most Eastern European countries, injecting drug use remains one of the leading transmission modes of HIV infection. This paper aims to identify HIV prevalence and risk determinants among people who inject drugs (PWID).

Methodology: A cross -sectional, anonymous bio-behavioral survey of PWID was conducted in seven cities of Georgia in 2014-2015. Overall 2,022 PWID were investigated. Bivariate and multivariate regression analyses were performed to identify association of HIV positivity with other factors.

Results: HIV prevalence among PWID was (2.2%, 95% CI 1.53-2.99). Significant associations were found between HIV positivity and history of drug injection (OR 1.03, p < 0.05), older age at first drug injection (OR 3.94, p <  0.01), safe sex behavior last year (OR 5.32, p < 0.01) and preventive program coverage (OR 2.0, p < 0.05).

Conclusions: HIV prevalence among PWID is stable and remains at low level. Our study shows that preventive interventions influence the sexual behavior of HIV positive PWID, however, the majority of injecting drug users are still not reached with these interventions. A changing environment may present additional challenges for harm reduction and current safe practices may change unless continuously supported by innovative HIV prevention programming.
Toxin production and drug resistance profiles of pediatric methicillin-resistant Staphylococcus aureus isolates in Tehran
Authors: Esmaeili Benvidi Mozhgan , Houri Hamidreza , Ghalavand Zohreh , Nikmanesh Bahram , Azimi Hadi , Samadi Roghayeh , Nodeh Farahani Narges , Eslami Gita
Published: November 2017

Introduction: Staphylococcus aureus is known to be a major cause of skin and soft tissue infections, pneumonia and invasive diseases. In this study, attempts were made to examine the prevalence of tsst-1, eta, etb, and luk-PV genes among methicillin-resistant S. aureus (MRSA) isolated from children in Tehran.

Methodology: In the present cross-sectional study, a total of 100 MRSA were isolated from children who were referred to a pediatric hospital during 11-month period of September 2014 to August 2015. Isolates were identified using biochemical tests and then, using PCR, the isolates were tested for the presence of mecA, tsst-1, eta, etb, and luk-PV genes. Susceptibility of isolates to cefoxitin, penicillin, erythromycin, clindamycin, gentamicin, rifampin, minocycline, co-trimoxazole, linezolid, and vancomycin were evaluated using standard methods.

Results: It was found that the MRSA isolates had the greatest resistance to clindamycin (72%) and erythromycin (59%), while the lowest rates of resistance were observed to be related to minocycline (6%) and rifampin (12%). All of isolates were sensitive to vancomycin and linezolid. The mecA gene was detected in all the isolates. Moreover, luk-PV and tsst-1 were detected in 18% and 17% of the isolates, respectively. None of the isolates harbored eta and etb genes.

Conclusions: Our data provide specifications about the toxin production status of S. aureus isolates from pediatric children. The current study showed increased resistance to different antibiotics in S. aureus isolates. Therefore, to prevent multi-resistance to other antibiotic classes, it is essential to withhold prescriptions and stop unessential use of available antibiotics.
Expliquer la rupture du Programme commun de gouvernement en septembre 1977
Authors: Batardy Christophe
Published: November 2017

Le 12 juillet 1972, le Parti communiste français (PCF), le Parti socialiste (PS) et les radicaux de gauche signent un accord programmatique, le Programme commun de gouvernement, appelé très vite Programme commun. Les discussions sur l’actualisation débutent en mai 1977 pour échouer en septembre 1977. Le Programme n’est dès lors plus partagé et la gauche perd les élections législatives de mars 1978. Une lecture chronologique de la période qui court de mai à septembre 1977 permet de revenir sur les causes de cette rupture, et de réévaluer la responsabilité du Parti communiste et de son secrétaire général Georges Marchais.
Marie Claire , magazine féministe ?
Authors: Pavard Bibia
Published: November 2017

Existe-t-il un féminisme populaire porté par la presse féminine ? L’étude de cas du cahier « Femmes » de Marie Claire , autoproclamé « journal des féministes » dans le magazine de 1976 à 1990, permet d’analyser finement les mécanismes de diffusion de discours militants dans la culture de masse. L’étude qualitative de la rubrique couplée à des entretiens avec les professionnels qui l’ont animée montrent que cette expérience éditoriale originale est rendue possible par le poids du contexte politique s’articulant avec le contexte organisationnel de l’entreprise et les trajectoires des journalistes. Le magazine propose une rubrique qui suit l’air du temps, permettant à une jeune génération d’entrer dans la rédaction et d’y faire carrière.