bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrative interaction analysis using threshold gradient directed regularization
Authors: Li Yang , Li Rong , Qin Yichen , Wu Mengyun , Ma Shuangge
Published: May 2018

For many complex business and industry problems, high‐dimensional data collection and modeling have been conducted. It has been shown that interactions may have important implications beyond the main effects. The number of unknown parameters in an interaction analysis can be larger or much larger than the sample size. As such, results generated from analyzing a single data set are often unsatisfactory. Integrative analysis, which jointly analyzes the raw data from multiple independent studies, has been conducted in a series of recent studies and shown to outperform single–data set analysis, meta‐analysis, and other multi–data set analyses. In this study, our goal is to conduct integrative analysis in interaction analysis. For regularized estimation and selection of important interactions (and main effects), we apply a threshold gradient directed regularization approach. Advancing from the existing studies, the threshold gradient directed regularization approach is modified to respect the “main effects, interactions” hierarchy. The proposed approach has an intuitive formulation and is computationally simple and broadly applicable. Simulations and the analyses of financial early warning system data and news‐APP (application) recommendation behavior data demonstrate its satisfactory practical performance.
A BIC‐based consistent metric between Markovian processes
Authors: García Jesús E. , Gholizadeh R. , González‐López V. A.
Published: May 2018

In this paper, we address the problem of deciding if two independent samples coming from discrete Markovian processes are governed by the same stochastic law. We establish a local metric between samples based on the Bayesian information criterion. In addition, we derive the bound that must be used in this metric to take the decision. In the case on which is decided that the laws are not the same, the metric allows to detect the specific elements of the state space where the discrepancies are manifested. We prove that the metric is statistically consistent to detect if the samples follow the same law, tending to zero when the sample sizes increase. Moreover, we show that the metric assumes arbitrarily large values when the sample sizes increase and the stochastic laws are different. This concept is applied to analyze two lines of production of alcohol fuel, described by five variables each. We identify the variables that most contribute to the discrepancy and, using the local nature of the metric, we list the realizations in which the processes behave differently.
One‐Step Fabrication of Hydrophobic Hybrid Gate Dielectrics for Low‐Voltage Organic Thin‐Film Transistors
Authors: Byun Hye‐Ran , Ha Young‐Geun
Published: May 2018

We report here on the design, processing, and dielectric properties of low surface energy organic/inorganic hybrid dielectric films for low‐voltage operation of organic thin‐film transistors (OTFTs). The hydrophobic hybrid dielectric films are easily fabricated by one‐step spin coating of a zirconium chloride precursor in an octadecyltrimethoxysilane solution under ambient conditions, followed by thermal curing at low temperatures (approximately 150°C). These novel dielectrics exhibit excellent surface smoothness (root‐mean‐square roughness is <0.5 nm), great insulating property (leakage current densities <10−6 A/cm2), and high capacitance (365 nF/cm2). In addition, the surface nature of the hybrid dielectric is hydrophobic (water contact angle is 105°), without any further surface modifications, which is highly compatible with organic semiconductors. Consequently, the hybrid dielectrics integrated into the pentacene OTFTs function at relatively low voltages (< −2.5 V) with excellent TFT characteristics (mobility: 0.31 cm2/V·s, on/off current ratio: 105, low threshold voltage: down to −0.7 V).
Compatibility effects of herb pair Phellodendri chinensis cortex and Anemarrhenae rhizoma on benign prostatic hyperplasia using targeted metabolomics
Authors: Zhao Xiaoning , Li Yiran , Huai Jiaxin , Cheng Congcong , Zhang Teng , Xie Linlin , Wang Siqi , Zhang Meng , Dai Ronghua
Published: May 2018

Phellodendri chinensis cortex (P. C. cortex) and Anemarrhenae rhizoma (A. rhizoma) herb pair is a core component of traditional Chinese medicines used to treat inflammation and benign prostatic hyperplasia (BPH). The present study was designed to profile the arachidonic acid (AA) metabolomic characteristics in rat plasma and prostate after being treated with P. C. cortex and A. rhizoma as well as their combination. Plasma and prostate samples from sham group, BPH model group, herb pair group and two single herb groups were collected on days 7, 14, 21 and 28. Then, a systemic metabolomic analysis based on UFLC‐MS/MS was employed to quantify AA and its cyclooxygenase and lipoxygenase pathway metabolites (15‐HETE, 12‐HETE, 5‐HETE, AA, PGI2, PGF2α, 8‐HETE, PGD2, PGE2 and LTB4). The results demonstrated that BPH led a significant increase of 10 biomarkers in plasma and tissue (p < 0.05). The clusters of herb pair group and single herb groups showed a tendency to return to the initial space, and the AA and its metabolites from those groups were differently downregulated to a healthier level, with the combination of single herbs most obvious. The present study demonstrated that P. C. cortex–A. rhizoma herb pair might produce synergistic or complementary compatibility effects on suppressing inflammatory processes occurring in BPH.
Artificial Light Regulation of an Allosteric Bienzyme Complex by a Photosensitive Ligand
Authors: Kneuttinger Andrea C. , Winter Martin , Simeth Nadja A. , Heyn Kristina , Merkl Rainer , König Burkhard , Sterner Reinhard
Published: May 2018

The artificial regulation of proteins by light is an emerging subdiscipline of synthetic biology. Here, we used this concept to photocontrol both catalysis and allostery within the heterodimeric enzyme complex imidazole glycerol phosphate synthase (ImGP‐S). ImGP‐S consists of the cyclase subunit HisF and the glutaminase subunit HisH, which is allosterically stimulated by substrate binding to HisF. We show that a light‐sensitive diarylethene (1,2‐dithienylethene, DTE)‐based competitive inhibitor in its ring‐open state binds with low micromolar affinity to the cyclase subunit and displaces its substrate from the active site. As a consequence, catalysis by HisF and allosteric stimulation of HisH are impaired. Following UV‐light irradiation, the DTE ligand adopts its ring‐closed state and loses affinity for HisF, restoring activity and allostery. Our approach allows for the switching of ImGP‐S activity and allostery during catalysis and appears to be generally applicable for the light regulation of other multienzyme complexes.
Identification of integrin heterodimers functioning on the surface of undifferentiated porcine primed embryonic stem cells
Authors: Kim Hwa‐Young , Baek Song , Han Na Rae , Lee Eunsong , Park Choon‐Keun , Lee Seung Tae
Published: May 2018

In vitro expansion of undifferentiated porcine primed embryonic stem (ES) cells is facilitated by use of non‐cellular niches that mimic three‐dimensional (3D) microenvironments enclosing an inner cell mass of porcine blastocysts. Therefore, we investigated the integrin heterodimers on the surface of undifferentiated porcine primed ES cells for the purpose of developing a non‐cellular niche to support in vitro maintenance of the self‐renewal ability of porcine primed ES cells. Immunocytochemistry and a fluorescence immunoassay were performed to assess integrin α and β subunit levels, and attachment and antibody inhibition assays were used to evaluate the function of integrin heterodimers. The integrin α3, α5, α6, α9, αV, and β1 subunits, but not the α1, α2, α4, α7, and α8 subunits, were identified on the surface of undifferentiated porcine primed ES cells. Subsequently, significant increase of their adhesion to fibronectin, tenascin C, and vitronectin were observed and functional blocking of integrin heterodimer α5β1, α9β1, or αVβ1 showed significantly inhibited adhesion to fibronectin, tenascin C, or vitronectin. No integrin α6β1 heterodimer‐mediated adhesion to laminin was detected. These results demonstrate that active α5β1, α9β1, and αVβ1 integrin heterodimers are present on the surface of undifferentiated porcine primed ES cells, together with inactive integrin α3 (presumed) and α6 subunits.
Down‐regulation of CD19 expression inhibits proliferation, adhesion, migration and invasion and promotes apoptosis and the efficacy of chemotherapeutic agents and imatinib in SUP‐B15 cells
Authors: Wu Junqing , Liang Bin , Qian Yan , Tang Liyuan , Xing Chongyun , Zhuang Qiang , Shen Zhijian , Jiang Songfu , Yu Kang , Feng Jianhua
Published: May 2018

The survival rate of childhood acute lymphoblastic leukemia (ALL) has increased while that of Philadelphia‐positive (Ph+) ALL remains low. CD19 is a B‐cell specific molecule related to the survival and proliferation of normal B cells. However, there is little information available on the effects of CD19 on the biological behavior of Ph+ ALL cells. In this study, we explored a lentiviral vector‐mediated short hairpin RNA (shRNA) expression vector to stably reduce CD19 expression in Ph+ ALL cell line SUP‐B15 cells and investigated the effects of CD19 downregulation on cell proliferation, apoptosis, drug sensitivity, cell adhesion, cell migration and cell invasion in vitro. CD19 mRNA and protein expression levels were inhibited significantly by CD19 shRNA. Down‐regulation of CD19 could inhibit cell proliferation, adhesion, migration and invasion, and increase cell apoptosis and the efficacy of chemotherapeutic agents and imatinib in SUP‐B15 cells. Moreover, we found that down‐regulation of CD19 expression inhibits cell proliferation and induces apoptosis in SUP‐B15 cells in a p53‐dependent manner. Taken together, our results suggest that lentiviral vector‐mediated RNA interference of CD19 gene may be a promising strategy in the treatment of Ph+ ALL.
Two Unconventional Precursors to Produce ZnCl2‐Based Activated Carbon for Water Treatment Applications
Authors: Cruz Gerardo Juan Francisco , Pirilä Minna , Matějová Lenka , Ainassaari Kaisu , Solis Jose Luis , Fajgar Radek , Šolcová Olga , Keiski Riitta Liisa
Published: May 2018

Two unconventional raw materials, the seeds from Spondias purpurea L. (red mombin) and Inga edulis (ice cream bean), were characterized and used as precursors to produce good‐quality zinc chloride‐activated carbons for potential use in water treatment applications. The red mombin seed was significantly more porous than the ice cream bean seed, while the activated carbons prepared from red mombin seed and ice cream bean seeds showed both a very well‐established microporous‐mesoporous structure. Equilibrium as well as kinetic adsorption experiments were conducted with methylene blue, methyl orange, and As(V). It was revealed that both seeds are unconventional, renewable, cheap, and suitable agro‐precursors for production of activated carbons with potential application in wastewater treatment.
Strong Aggregation‐Induced CPL Response Promoted by Chiral Emissive Nematic Liquid Crystals (N*‐LCs)
Authors: Li Xiaojing , Li Qian , Wang Yuxiang , Quan Yiwu , Chen Dongzhong , Cheng Yixiang
Published: May 2018

In this paper we designed a kind of aggregation‐induced emission (AIE) chiral fluorescence emitters (R/S‐BINOL‐CN enantiomers) in the aggregate state. Chiral emissive nematic liquid crystals (N*‐LCs) prepared by doping this kind of AIE‐activeR/S‐BINOL‐CN enantiomers into a common achiral nematic liquid crystal (N‐LC, E7) can self‐assemble as the regularly planar Grandjean texture leading to high luminescence dissymmetry factor (glum) of aggregation‐induced circularly polarized luminescence (AI‐CPL) signal up to 0.41, which can be attributed to dipolar interactions from polar cyano groups and π–π interactions between binaphthyl moiety of the dopantR/S‐BINOL‐CN and biphenyl group of the host molecules (E7).
Post‐Synthetic Mannich Chemistry on Metal‐Organic Frameworks: System‐Specific Reactivity and Functionality‐Triggered Dissolution
Authors: Amer Hamzah Harina , Gee William J. , Raithby Paul R. , Teat Simon J. , Mahon Mary F. , Burrows Andrew D.
Published: May 2018

The Mannich reaction of the zirconium MOF [Zr6O4(OH)4(bdc‐NH2)6] (UiO‐66‐NH2, bdc‐NH2=2‐amino‐1,4‐benzenedicarboxylate) with paraformaldehyde and pyrazole, imidazole or 2‐mercaptoimidazole led to post‐synthetic modification (PSM) through C−N bond formation. The reaction with imidazole (Him) goes to completion whereas those with pyrazole (Hpyz) and 2‐mercaptoimidazole (HimSH) give up to 41 and 36 % conversion, respectively. The BET surface areas for the Mannich products are reduced from that of UiO‐66‐NH2, but the compounds show enhanced selectivity for adsorption of CO2 over N2 at 273 K. The thiol‐containing MOFs adsorb mercury(II) ions from aqueous solution, removing up to 99 %. The Mannich reaction with pyrazole succeeds on [Zn4O(bdc‐NH2)3] (IRMOF‐3), but a similar reaction on [Zn2(bdc‐NH2)2(dabco)] (dabco=1,4‐diazabicyclo[2.2.2]octane) gave [Zn3(bdc‐NH2)1.32(bdc‐NHCH2pyz)1.68(dabco)]⋅2 C7H8 5, whereas the reaction with imidazole gave the expected PSM product. Compound 5 forms via a dissolution–recrystallisation process that is triggered by the “free” pyrazolate nitrogen atom competing with dabco for coordination to the zinc(II) centre. In contrast, the “free” nitrogen atom on the imidazolate is too far away to compete in this way. Mannich reactions on [In(OH)(bdc‐NH2)] (MIL‐68(In)‐NH2) stop after the first step, and the product was identified as [In(OH)(bdc‐NH2)0.41(bdc‐NHCH2OCH3)0.30(bdc‐N=CH2)0.29], with addition of the heterocycle prevented by steric interactions.
Survey on the theoretical research and engineering applications of multivariate statistics process monitoring algorithms: 2008–2017
Authors: Wang Youqing , Si Yabin , Huang Biao , Lou Zhijiang
Published: May 2018

Multivariate statistical process monitoring (MSPM) methods are significant for improving production efficiency and enhancing safety. However, to the authors’ best knowledge, there is no survey paper providing statistics of published papers over the past decade. In this paper, several issues related to MSPM methods are reviewed and studied. First, the annual publication numbers of journal articles concerning MSPM are provided to show the active development of this important research field and to point out several promising directions in the future. Second, the annual numbers of patents are also shown to demonstrate the practicality of different MSPM methods. Particularly, this paper also lists and analyzes the number of MSPM‐related publications in China. The statistics indicate that Chinese researchers and engineers may have different viewpoints from those of other countries, which results in different development trends of MSPM in China.
An approach to custom privacy policy violation detection problems using big social provenance data
Authors: Baeth Mohamed Jehad , Aktas Mehmet S.
Published: May 2018

Social media software changes its system‐wide privacy policies over time. Changes in such system‐wide policies affect the privacy policies of the individual users. In turn, social media users lack the ability to configure and enforce customized privacy policies according to the precise privacy measure that they demand. To this end, we argue that there is an emerging need for third‐party solutions that are independent of existing social media software and that can detect custom privacy policy violations. In order to address this need, we propose an approach to detecting custom privacy violations for social media users. We also introduce a generic software architecture that can be integrated with existing social media software to enable users to keep track of their data. The proposed solution utilizes social provenance data, which is defined as the metadata that describe the lifecycle of the data. To facilitate testing of the software architecture, we developed a prototype implementation and generated a large‐scale synthetic provenance dataset. We discuss the details of the prototype implementation and the synthetic dataset. We evaluate the performance of the prototype under an increasing workload. We show the usability of the proposed architecture, as the initial performance testing results are promising.
Oxidatively‐Stable Linear Poly(propylenimine)‐Containing Adsorbents for CO2 Capture from Ultradilute Streams
Authors: Pang Simon H. , Lively Ryan P. , Jones Christopher W.
Published: May 2018

Aminopolymer‐based solid sorbents have been widely investigated for the capture of CO2 from dilute streams such as flue gas or ambient air. However, the oxidative stability of the widely studied aminopolymer, poly(ethylenimine) (PEI), is limited, causing it to lose its CO2 capture capacity after exposure to oxygen at elevated temperatures. Here, we demonstrate the use of linear poly(propylenimine) (PPI), synthesized through a simple cationic ring‐opening polymerization, as a more oxidatively stable alternative to PEI with high CO2 capacity and amine efficiency. The performance of linear PPI/SBA‐15 composites was investigated over a range of CO2 capture conditions (CO2 partial pressure, adsorption temperature) to examine the tradeoff between adsorption capacity and sorption‐site accessibility, which was expected to be more limited in linear polymers relative to the prototypical hyperbranched PEI. Linear PPI/SBA‐15 composites were more efficient at CO2 capture and retained 65–83 % of their CO2 capacity after exposure to a harsh oxidative treatment, compared to 20–40 % retention for linear PEI. Additionally, we demonstrated long‐term stability of linear PPI sorbents over 50 adsorption/desorption cycles with no loss in performance. Combined with other strategies for improving the oxidative stability and adsorption kinetics, linear PPI may play a role as a component of stable solid adsorbents in commercial applications for CO2 capture.
Adjusting the Introduction of Cations for Highly Efficient and Stable Perovskite Solar Cells Based on (FAPbI3)0.9(FAPbBr3)0.1
Authors: Liu Guozhen , Zheng Haiying , Zhu Liangzheng , Alsaedi Ahmed , Hayat Tasawar , Pan Xu , Mo Li'e , Dai Songyuan
Published: May 2018

Although the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has increased to 22.7 %, the instability when exposed to moisture and heat has hindered their further practical development. In this study, to gain highly efficient and stable perovskite components, methylammonium (MA), Cs, and Rb cations are introduced into a (FAPbI3)0.9(FAPbBr3)0.1 (FA=formamidine) film, which is rarely used because of its poor photovoltaic performance. The effects of different contents of MA, Cs, or Rb cations on the performance of (FAPbI3)0.9(FAPbBr3)0.1 films and devices are systematically studied. The results show that the devices with Cs cations exhibit markedly improved photovoltaic performance and stability, attributed to the clearly enhanced quality of films and their intrinsic stability. The (FAPbI3)0.9(FAPbBr3)0.1 devices with 10 % Cs show a PCE as high as 19.94 %. More importantly, the unsealed devices retain about 80 % and 90 % of the initial PCE at 85 °C after 260 h and under 45±5 % relative humidity (RH) after 1440 h, respectively, which are better than that with 15 % MA and 5 % Rb under the same conditions. This indicates that a highly efficient and stable perovskite component has been achieved, and PSCs based on this component are expected to promote their further development.
Highly Active Catalytic Ruthenium/TiO2 Nanomaterials for Continuous Production of γ‐Valerolactone
Authors: Xu Chunping , Ouyang Weiyi , Muñoz‐Batista Mario J. , Fernández‐García Marcos , Luque Rafael
Published: May 2018

Green energy production from renewable sources is an attractive, but challenging topic to face the likely energy crisis scenario in the future. In the current work, a series of versatile Ru/TiO2 catalysts were simply synthesized and employed in continuous‐flow catalytic transfer hydrogenation of industrially derived methyl levulinate biowaste (from Avantium Chemicals B.V.) to form γ‐valerolactone. Different analytical techniques were applied in the characterization of the as‐synthesized catalysts, including XRD, SEM, energy‐dispersion X‐ray spectroscopy, TEM, and X‐ray photoelectron spectroscopy. The effects of various reaction conditions (e.g., temperature, concentration, and flow rate) were investigated. Results suggested that optimum dispersion and distribution of Ru on the TiO2 surface could efficiently promote the production of γ‐valerolactone; the 5 % Ru/TiO2 catalyst provided excellent catalytic performance and stability compared with commercial Ru catalysts.
Water Splitting–Biosynthetic Hybrid System for CO2 Conversion using Nickel Nanoparticles Embedded in N‐Doped Carbon Nanotubes
Authors: Li Zhongjian , Li Gang , Chen Xinlu , Xia Zheng , Yao Jiani , Yang Bin , Lei Lecheng , Hou Yang
Published: May 2018

CO2 reduction has drawn increasing attention owing to the concern of global warming. Water splitting–biosynthetic hybrid systems are novel and efficient approaches for CO2 conversion. Intimate coupling of electrocatalysts and biosynthesis requires the catalysts possess both high catalytic performance and excellent biocompatibility, which is a bottleneck of developing such catalysts. Here, a complex of Ni nanoparticles embedded in N‐doped carbon nanotubes (Ni@N‐C) is synthesized as a hydrogen evolution reaction electrocatalyst and is coupled with a hydrogen oxidizing autotroph, Cupriavidus necator H16, to convert CO2 to poly‐β‐hydroxybutyrate. In Ni@N‐C, the Ni nanoparticles are encapsulated in N‐C nanotubes, which prevents bacteria from direct contact with Ni and inhibits Ni2+ leaching. As a result, Ni@N‐C exhibits excellent biocompatibility and stability. This work demonstrates that electrocatalysts and biosynthesis can be intimately coupled through rational catalyst design.
Oxygen Evolution Catalysts Based on Ir–Ti Mixed Oxides with Templated Mesopore Structure: Impact of Ir on Activity and Conductivity
Authors: Bernsmeier Denis , Bernicke Michael , Schmack Roman , Sachse René , Paul Benjamin , Bergmann Arno , Strasser Peter , Ortel Erik , Kraehnert Ralph
Published: May 2018

The efficient generation of hydrogen via water electrolysis requires highly active oxygen evolution catalysts. Among the active metals, iridium oxide provides the best compromise in terms of activity and stability. The limited availability and usage in other applications demands an efficient utilization of this precious metal. Forming mixed oxides with titania promises improved Ir utilization, but often at the cost of a low catalyst surface area. Moreover, the role of Ir in establishing a sufficiently conductive mixed oxide has not been elucidated so far. We report a new approach for the synthesis of Ir/TiOx mixed‐oxide catalysts with defined template‐controlled mesoporous structure, low crystallinity, and superior oxygen evolution reaction (OER) activity. The highly accessible pore system provides excellent Ir dispersion and avoids transport limitations. A controlled variation of the oxides Ir content reveals the importance of the catalysts electrical conductivity: at least 0.1 S m−1 are required to avoid limitations owing to slow electron transport. For sufficiently conductive oxides a clear linear correlation between Ir surface sites and OER currents can be established, where all accessible Ir sites equally contribute to the reaction. The optimized catalysts outperform Ir/TiOx materials reported in literature by about a factor of at least four.
High‐Performance Solid Oxide Fuel Cell with an Electrochemically Surface‐Tailored Oxygen Electrode
Authors: Park Beom‐Kyeong , Lee Seung‐Bok , Lim Tak‐Hyoung , Song Rak‐Hyun , Lee Jong‐Won
Published: May 2018

State‐of‐the‐art cathodes for solid oxide fuel cells (SOFCs), such as (La,Sr)MnO3–(Y2O3)0.08(ZrO2)0.92 (LSM–YSZ), suffer from sluggish oxygen reduction reaction (ORR) kinetics at reduced temperatures, leading to a significant decline in their performance. Herein, we report a tailored SOFC cathode with high ORR activity at intermediate temperatures using a simple but effective approach based on “electrochemical” surface modification. The proposed process involves chemically assisted electrodeposition (CAED) of a metal hydroxide (LaCo(OH)x) on LSM–YSZ surfaces followed by in situ thermal conversion of LaCo(OH)x to perovskite‐type LaCoO3 (LCO) nanoparticles during the SOFC startup. This method facilitates easy loading of the LCO nanoparticles with a precisely controlled morphology without the need for repeated deposition/annealing processes. An anode‐supported SOFC with the LCO‐tailored LSM–YSZ electrode exhibits a remarkably increased power density, approximately 180 % at 700 °C, compared with an SOFC with the pristine electrode as well as excellent long‐term stability, which are attributed to the beneficial role of the CAED‐derived LCO nanoparticles in enlarging the active areas for ORR and promoting oxygen adsorption/diffusion. This work demonstrates that controlled surface tailoring of the cathode by CAED could be an effective approach for improving the performance of SOFCs at reduced temperatures.
Tuning the Gas Selectivity of Tröger's Base Polyimide Membranes by Using Carboxylic Acid and Tertiary Base Interactions
Authors: Wang Zhenggong , Isfahani Ali Pournaghshband , Wakimoto Kazuki , Shrestha Binod Babu , Yamaguchi Daisuke , Ghalei Behnam , Sivaniah Easan
Published: May 2018

Polyimide‐based materials provide attractive chemistries for the development of gas‐separation membranes. Modification of inter‐ and intra‐chain interactions is a route to improve the separation performance. In this work, copolyimides with Tröger's base (TB) monomers are designed and synthesized. In particular, a series of copolyimides is synthesized with different contents of carboxylic acid groups (0–50 wt %) to alter the inter‐ and intra‐chain interactions and enhance the basicity of the TB‐polyimides. A detailed thermal and structural analysis is provided for the new copolyimides. Gas permeation data reveal a tunable trend in separation performance with increasing carboxylic acid group content. Importantly, this is one of the few examples of copolyimide membranes materials that show enhanced plasticization resistance to high‐pressure gas feeds through physical cross‐linking.
Distributed fuzzy approach to unequal clustering and routing algorithm for wireless sensor networks
Authors: Mazumdar Nabajyoti , Om Hari
Published: May 2018

Due to inherent issue of energy limitation in sensor nodes, the energy conservation is the primary concern for large‐scale wireless sensor networks. Cluster‐based routing has been found to be an effective mechanism to reduce the energy consumption of sensor nodes. In clustered wireless sensor networks, the network is divided into a set of clusters; each cluster has a coordinator, called cluster head (CH). Each node of a cluster transmits its collected information to its CH that in turn aggregates the received information and sends it to the base station directly or via other CHs. In multihop communication, the CHs closer to the base station are burdened with high relay load; as a result, their energy depletes much faster as compared with other CHs. This problem is termed as the hot spot problem. In this paper, a distributed fuzzy logic‐based unequal clustering approach and routing algorithm (DFCR) is proposed to solve this problem. Based on the cluster design, a multihop routing algorithm is also proposed, which is both energy efficient and energy balancing. The simulation results reinforce the efficiency of the proposed DFCR algorithm over the state‐of‐the‐art algorithms, ie, energy‐aware fuzzy approach to unequal clustering, energy‐aware distributed clustering, and energy‐aware routing algorithm, in terms of different performance parameters like energy efficiency and network lifetime.
Screening of drugs and homeopathic products from Atropa belladonna seed extracts: Tropane alkaloids determination and untargeted analysis
Authors: Marín‐Sáez Jesús , Romero‐González Roberto , Garrido Frenich Antonia , Egea‐González Francisco Javier
Published: May 2018

Homeopathic products are still a controversial issue in modern medicine, understood as complementary or alternative medicine (CAM). In this particular case, homeopathic products prepared from Atropa belladonna extracts may present specific problems due to the effects derived from its components. This article applies a simple, rapid, reliable method to the analysis of different homeopathic products obtained from Atropa belladonna; drugs containing high concentration of plant extracts; and Atropa belladonna seeds. The method was based on a simple solid‐phase preconcentration method followed by ultra‐high pressure liquid chromatography (UHPLC) coupled to high resolution mass spectrometry using Exactive‐Orbitrap as an analyser. An in‐house database was set and atropine and scopolamine were the compounds detected at highest concentrations in homeopathic products from Atropa belladonna extracts (4.57 and 2.56 μg/kg, respectively), in Belladonna ointment (4007 and 1139 μg/kg, respectively) and Belladonna seeds (338 and 32.1 mg/kg, respectively). Other tropane alkaloids such as tropine, apoatropine, aposcopolamine, tropinone, homatropine, and anisodamine were detected at lower concentrations (0.04–1.36 μg/kg). When untargeted analysis was performed, other tropane alkaloids were identified in the tested samples, such as ecgonine (0.003 μg/kg), benzoylecgonine (0.56 μg/kg), calystegines A (19.6 μg/kg), B (33.1 μg/kg), and C (1.01 μg/kg). Finally other compounds present in the homeopathic products, such as sugars (fructose, glucose, and lactose) or amino acids (valine, ornithine, leucine, and phenylalanine), were identified.
The role of environmental driving factors in historical and projected carbon dynamics of wetland ecosystems in Alaska
Authors: Lyu Zhou , Genet Hélène , He Yujie , Zhuang Qianlai , McGuire A. David , Bennett Alec , Breen Amy , Clein Joy , Euskirchen Eugénie S. , Johnson Kristofer , Kurkowski Tom , Pastick Neal J. , Rupp T. Scott , Wylie Bruce K. , Zhu Zhiliang
Published: May 2018

Wetlands are critical terrestrial ecosystems in Alaska, covering ~177,000 km2, an area greater than all the wetlands in the remainder of the United States. To assess the relative influence of changing climate, atmospheric carbon dioxide (CO2) concentration, and fire regime on carbon balance in wetland ecosystems of Alaska, a modeling framework that incorporates a fire disturbance model and two biogeochemical models was used. Spatially explicit simulations were conducted at 1‐km resolution for the historical period (1950–2009) and future projection period (2010–2099). Simulations estimated that wetland ecosystems of Alaska lost 175 Tg carbon (C) in the historical period. Ecosystem C storage in 2009 was 5,556 Tg, with 89% of the C stored in soils. The estimated loss of C as CO2 and biogenic methane (CH4) emissions resulted in wetlands of Alaska increasing the greenhouse gas forcing of climate warming. Simulations for the projection period were conducted for six climate change scenarios constructed from two climate models forced under three CO2 emission scenarios. Ecosystem C storage averaged among climate scenarios increased 3.94 Tg C/yr by 2099, with variability among the simulations ranging from 2.02 to 4.42 Tg C/yr. These increases were driven primarily by increases in net primary production (NPP) that were greater than losses from increased decomposition and fire. The NPP increase was driven by CO2 fertilization (~5% per 100 parts per million by volume increase) and by increases in air temperature (~1% per °C increase). Increases in air temperature were estimated to be the primary cause for a projected 47.7% mean increase in biogenic CH4 emissions among the simulations (~15% per °C increase). Ecosystem CO2 sequestration offset the increase in CH4 emissions during the 21st century to decrease the greenhouse gas forcing of climate warming. However, beyond 2100, we expect that this forcing will ultimately increase as wetland ecosystems transition from being a sink to a source of atmospheric CO2 because of (1) decreasing sensitivity of NPP to increasing atmospheric CO2, (2) increasing availability of soil C for decomposition as permafrost thaws, and (3) continued positive sensitivity of biogenic CH4 emissions to increases in soil temperature.
Synthesis and Properties of Acridine and Acridinium Dye Functionalized Bis(terpyridine) Ruthenium(II) Complexes
Authors: Eberhard Jens , Peuntinger Katrin , Fröhlich Roland , Guldi Dirk M. , Mattay Jochen
Published: May 2018

We present first principle studies on the rational design of an acridine/N‐methylacridinium dye (Acr/MeAcr+) substituted terpyridine ligand to investigate if these chromophores can act as triplet‐energy storage units in bis(terpyridine) ruthenium(II) complexes. We studied the influence of the dye form (Acr/MeAcr+) as well as the interconnecting linker unit (none, 4‐phenyl, or 5‐thien‐2‐yl) and investigated these aspects by steady‐state/time‐resolved spectroscopy, cyclic voltammetry, X‐ray structure analysis, and DFT calculations.
Methods for the Synthesis of α,α‐Difluoroketones
Authors: Pattison Graham
Published: May 2018

α,α‐Difluoroketones are valuable compounds and can be used as synthetic intermediates for the synthesis of fluorinated molecules, but they also have a direct application in medicinal chemistry, particularly as inhibitors for hydrolytic enzymes. This Microreview will summarize the major methods currently available for the synthesis of α,α‐difluoroketones, highlighting methods involving direct C–F bond formation, as well as those using pre‐difluorinated building blocks.
Facile and Efficient Synthesis of 3‐Pyrimidinyl Oxindoles by Phase‐Transfer‐Catalyzed Regioselective Nucleophilic Aromatic Substitution
Authors: Brüning Fabian , Katayev Dmitry , Togni Antonio
Published: May 2018

Phase‐transfer‐catalyzed regioselective nucleophilic aromatic substitution of 2,4‐dichloropyrimidines with N‐Boc‐protected 3‐substituted oxindoles is reported. The reaction allows the formation of unsymmetrical all‐ carbon quaternary centers in the benzylic position of heteroaromatic scaffolds and proceeds with high chemical yield and excellent functional‐group tolerance. Various activated heteroaryl chlorides including dichloropyridazine and activated chloropyridines can also be reacted under the reaction conditions.
Evaluation of Reduced Graphene Oxide Modified with Antimony and Copper Nanoparticles for Levofloxacin Oxidation
Authors: Da Silva Martin K. L. , Plana Simões Rafael , Cesarino Ivana
Published: May 2018

This work presents, for the first time, the oxidation mechanism of levofloxacin combining electrochemical experiments and molecular modelling techniques. Levofloxacin is one of the most widely used antibiotics in the world. The detection of this antibiotic is important, because it cannot be fully assimilated by the human organism, therefore levofloxacin is considerate a hazardous pollutant for environment. Sensors based on reduced graphene oxide (rGO) modified with antimony and copper nanoparticles (NPs) were synthesized, characterized and evaluated for the electrochemical detection of the levofloxacin. The morphological and electrochemical characterization of the composites confirmed that the rGO was modified with the metallic nanoparticles. Molecular modelling studies were performed applying Density Functional Theory (DFT) approach, which indicated that the mechanism of levofloxacin oxidation is given by the loss of two electrons: one from N14 atom and other from C13 atom of the levofloxacin molecule. The glassy carbon electrode (GCE) modified with the SbNPs/rGO and CuNPs/rGO composites were evaluated for the determination of levofloxacin using differential pulse voltammetry (DPV) and achieved detection limit of 4.1×10−8 mol L−1 and 1.7×10−8 mol L−1, respectively, presenting as alternative composites to be used in the analysis of antibiotics.
An optimized microfluidic paper‐based NiOOH/Zn alkaline battery
Authors: Burrola Samantha , Gonzalez‐Guerrero Maria Jose , Avoundjian Ani , Gomez Frank A.
Published: May 2018

In this paper, an alkaline nickel oxide hydroxide/zinc (NiOOH/Zn) battery featuring a cellulose matrix separator between electrodes is presented. The metallic electrodes and the paper separator are inserted in a layer‐by‐layer assembly that provides mechanical stability to the system resulting in a lightweight and easy‐to‐use device. The battery was optimized for the amount of NiOOH‐ink used at the cathode (11.1 mg/cm2) and thickness of the paper membrane separating the electrodes (360 μm). The battery was able to function using a small volume (75 μL) of 1.5 M potassium hydroxide (KOH) producing a maximum voltage, current density, and power density of 1.35 ± 0.05 V, 10.62 ± 0.57 mA/cm², and 0.56 ± 0.01 mW/cm², respectively. The system displayed a maximum current of 23.9 mA and a maximum power of 1.26 mW. Moreover, four batteries connected in series were able to power a small flameless candle for approximately 22 min. This work has potential in fulfilling the demands for short‐term and lightweight power supplies.
Super Nanoteragonal ZrO2 Embedded in Carbon as Efficient Support of PdAg Nanoparticle for Boosting Hydrogen Generation from Formic Acid
Authors: Feng Cheng , Gao Shutao , Shang Ningzhao , Zhou Xin , Wang Chun
Published: May 2018

The application of formic acid (FA) as a safe, renewable and promising hydrogen‐storage material has received considerable attention. However, exploring efficient heterogeneous catalysts for selective dehydrogenation of FA remains a challenging topic. In this paper, a super nanoteragonal ZrO2 (The crystallite size reached even 150 nm) is synthesized by calcining Zr‐based metal‐organic framework. Because the unique microstructures of the material which possess the electron‐rich property and surface basicity, the resulting PdAg@ZrO2/C catalyst exhibits excellent activity (Turnover frequency 9206 h−1 at 50 °C) for the decomposition of FA. These results may contribute to the design of efficient catalysts for dehydrogenation of FA and extended applications of tetragonal zirconia polycrysta without the dopants or reduction of the crystallite size.
Effect of irregular structural configuration on floor acceleration demand in hill‐side buildings
Authors: Surana Mitesh , Singh Yogendra , Lang Dominik H.
Published: May 2018

A suite of reinforced‐concrete frame buildings located on hill sides, with 2 different structural configurations, viz step‐back and split‐foundation, are analyzed to study their floor response. Both step‐back and split‐foundation structural configurations lead to torsional effects in the direction across the slope due to the presence of shorter columns on the uphill side. Peak floor acceleration and floor response spectra are obtained at each storey's center of rigidity and at both its stiff and flexible edges. As reported in previous studies as well, it is observed that the floor response spectra are better correlated with the ground response spectrum. Therefore, the floor spectral amplification functions are obtained as the ratio of spectral ordinates at different floor levels to the one at the ground level. Peaks are observed in the spectral amplification functions corresponding to the first 2 modes in the upper portion of the hill‐side buildings, whereas a single peak corresponding to a specific kth mode of vibration is observed on the floors below the uppermost foundation level. Based on the numerical study for the step‐back and split‐foundation hill‐side buildings, simple floor spectral amplification functions are proposed and validated. The proposed spectral amplification functions take into account both the buildings' plan and elevation irregularities and can be used for seismic design of acceleration‐sensitive nonstructural components, given that the supporting structure's dynamic characteristics, torsional rotation, ground‐motion response spectrum, and location of the nonstructural components within the supporting structure are known, because current code models are actually not applicable to hill‐side buildings.
Comparative Analysis of Two Online Identification Algorithms in a Fuel Cell System
Authors: Kandidayeni M. , Macias A. , Amamou A. A. , Boulon L. , Kelouwani S.
Published: May 2018

Output power of a fuel cell (FC) stack can be controlled through operating parameters (current, temperature, etc.) and is impacted by ageing and degradation. However, designing a complete FC model which includes the whole physical phenomena is very difficult owing to its multivariate nature. Hence, online identification of a FC model, which serves as a basis for global energy management of a fuel cell vehicle (FCV), is considerably important. In this paper, two well‐known recursive algorithms are compared for online estimation of a multi‐input semi‐empirical FC model parameters. In this respect, firstly, a semi‐empirical FC model is selected to reach a satisfactory compromise between computational time and physical meaning. Subsequently, the algorithms are explained and implemented to identify the parameters of the model. Finally, experimental results achieved by the algorithms are discussed and their robustness is investigated. The ultimate results of this experimental study indicate that the employed algorithms are highly applicable in coping with the problem of FC output power alteration, due to the uncertainties caused by degradation and operation condition variations, and these results can be utilized for designing a global energy management strategy in a FCV.
Thresholds and relations for soil‐hydraulic and soil‐physical properties as a function of burn severity 4 years after the 2011 Las Conchas Fire, New Mexico, USA
Authors: Ebel Brian A. , Romero Orlando C. , Martin Deborah A.
Published: May 2018

Wildfire effects on soil‐physical and ‐hydraulic properties as a function of burn severity are poorly characterized, especially several years after wildfire. A stratified random sampling approach was used in 2015 to sample seven sites representing a spectrum of remotely sensed burn severity in the area impacted by the 2011 Las Conchas Fire in New Mexico, USA. Replicate samples from each site were analysed in the laboratory. Linear and linear indicator regression were used to assess thresholds in soil‐physical and ‐hydraulic properties and functional relations with remotely sensed burn severity. Significant thresholds were present for initial soil‐water content (θi) at 0–6 cm depth between the change in the Normalized Burn Ratio (dNBR) equal to 618–802, for bulk density (ρb) at 3–6 cm between dNBR equal to 416–533, for gravel fraction at 0–1 cm between dNBR equal to 416–533, for fines (the silt + clay fraction) at 0–1 cm for dNBR equal to 416–533, and for fines at 3–6 cm for dNBR equal to 293–416. Significant linear relations with dNBR were present between ρb at 0–1 cm, loss on ignition (LOI) at 0–1 cm, gravel fraction at 0–1 cm, and the large organic fraction at 1–3 cm. No thresholds or effects on soil‐hydraulic properties of field‐saturated hydraulic conductivity or sorptivity were observed. These results suggest that ρb and LOI at 0–1 cm have residual direct impacts from the wildfire heat impulse. The θi threshold is most likely from delayed groundcover/vegetation recovery that increases evaporation at the highest burn severity sites. Gravel and silt + clay thresholds at 0–1 cm at the transition to high burn severity suggest surface gravel lag development from hydraulic erosion. Thresholds in ρb from 3 to 6 cm and in silt + clay fraction from 3 to 6 cm appear to be the result of soil variability between sites rather than wildfire impacts. This work suggests that gravel‐rich soils may have increased resilience to sustained surface runoff generation and erosion following wildfire, with implications for assessments of postwildfire hydrologic and erosion recovery potential.
Variables Reflecting the Mineralization of Bone Tissue From Fracturing Versus Nonfracturing Postmenopausal Nonosteoporotic Women
Authors: Rizzo Sébastien , Farlay Delphine , Akhter Mohammed , Boskey Adele , Recker Robert , Lappe Joan , Boivin Georges
Published: May 2018

Women with equivalent areal bone mineral densities may show a different fracture incidence due to differences in bone intrinsic quality. Previously, Fourier transform infrared spectroscopic imaging (FTIRI) on the same iliac bone biopsies reported here, showed that the only significantly different variable was the carbonate/phosphate ratio, which was decreased in the fracturing group. Nanoindentation showed that fracturing bone was less mechanically heterogeneous than nonfracturing bone and could propagate damage (microcracks) more easily. The hypothesis is that fracturing women have reduced mineralization of bone tissue compared to nonfracturing women. Transiliac bone biopsies were collected from fracturing (n = 60, 62.5 ± 7.4 years old) and nonfracturing (n = 60, 62.3 ± 7.3 years old) postmenopausal women, to assess the mineralization of bone tissue using digitized microradiography. The degree of mineralization of bone (DMB, g/cm3) and the heterogeneity index (HI, g/cm3) of the DMB were calculated for cancellous (canc), cortical (cort) and total bone. Results were compared to variables from nanoindentation, FTIRI, and histomorphometry. DMB and HI were not significantly different between fracturing and nonfracturing groups. In the nonfracturing group, cort and canc HI were weakly negatively associated with cort and canc DMB (r′ = −0.388, p < 0.003; r′ = −0.532, p < 0.0001, respectively). In the fracturing group, DMB and HI were negatively correlated only in canc (r′ = −0.295, p = 0.024). DMB and HI were not associated with nanoindentation variables. Cort and canc DMB were positively associated with mineral‐to‐matrix ratio measured by FTIRI (ratio between mineral and organic matrix representing the relative mineralization of the collagen matrix), and negatively associated with carbonate/phosphate ratio. None of the DMB variables were strongly associated with any of the histomorphometric variables. In conclusion, bone mineralization was not significantly different between fracturing and nonfracturing postmenopausal women, suggesting that bone fragility could be partly due to other variables, such as changes in hydration of bone matrix or an increase of non‐enzymatic crosslinks in bone collagen. © 2018 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
Genomewide Association Study of Fracture Nonunion Using Electronic Health Records
Authors: McCoy Thomas H , Fragomen Austin T , Hart Kamber L , Pellegrini Amelia M , Raskin Kevin A , Perlis Roy H
Published: May 2018

Nonunion is a clinically significant complication of fracture associated with worse outcomes, including increased pain, disability, and higher healthcare costs. The risk for nonunion is likely to be complex and multifactorial, and as such, the biology underlying such risk remains poorly understood. Genetic studies represent one approach to identify implicated biology for further investigation, but to date the lack of large cohorts for study has limited such efforts. We utilized the electronic health records of two large academic medical centers in Boston to identify individuals with fracture nonunion and control individuals with fracture but no evidence of nonunion. We conducted a genomewide association study among 1760 individuals of Northern European ancestry with upper or lower extremity fracture, including 131 with nonunion, to examine whether common variants were associated with nonunion in this cohort. In all, one locus in the Calcyon (CALY) gene exceeded a genomewide threshold for statistical significance (p = 1.95e–8), with eight additional loci associated with p < 5e–7. Previously reported candidate genes were not supported by this analysis. Electronic health records should facilitate identification of common genetic variations associated with adverse orthopedic outcomes. The loci we identified in this small cohort require replication and further study to characterize mechanism of action, but represent a starting point for the investigation of genetic liability for this costly outcome. © 2018 American Society for Bone and Mineral Research.