bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the Distributions of Nitrogen Dioxide in Nigeria using Neural Network
Authors: Ibeh G. F. , Udochukwu B. C. , Sombo T.
Published: April 2019

Nitrogen dioxide emission is part of atmospheric pollutant that has been linked to climate change. Artificial neural network model were used to investigate nitrogen dioxide distributions in Nigeria at a selected points. The study areas used in this work are thirty six (36) points over Nigeria as shown in Fig. 1. The data used in this work is a satellite nitrogen dioxide () obtained from Global Monitoring for Environment and Security (GMES) under the programme of Monitoring Atmospheric Composition and Climate (MACC). The data used in this work is a satellite nitrogen dioxide data obtained from 2003-2014. The neural network processed the available data by dividing them into three portions randomly: 70% for the training, 15% for validation and the remaining 15% for testing. Input parameters were chosen to be latitude, longitude, day of the year, year. Observed nitrogen dioxide was inputted as targeted data, while the output nitrogen dioxide data were the estimated data. The results reveal that dry and wet season variations differ in Nigeria. Nitrogen dioxide concentrations were observed to be higher in the North during dry season, but were higher in the South during the wet season. This could imply that weather condition and seasons influences the concentrations and variations of nitrogen dioxide in Nigeria. The similar trend of the estimated and observed nitrogen dioxide of both diurnal and annual distributions suggests good performance of the model. The result shows that high concentrations of nitrogen dioxide contribute to climate change in Nigeria, resulting to global warming. Consequently, if left unchecked, increase in nitrogen dioxide may cause alteration in rainfall regimes and patterns, floods, and so on. These in turn will bring about adverse effects on livelihoods, such as crop production, livestock production, fisheries, forestry and post-harvest activities. Finally, we recommend analysis of nitrogen dioxide distributions in Nigeria to be regular.
Breeding Potential and Multivariate Analyses of Morphological and Yield Traits in Industrial Sugarcane (Saccharum officinarum L.) Accessions in a Humid Tropical Agroecology
Authors: Ittah Macauley Asim , Obok Ekemini Edet
Published: April 2019

Sugarcane (Saccharum officinarum L.) is propagated mostly by vegetative method. Although vegetative propagation conserves plant germplasm; it poses challenges in crop breeding. This field study assessed the breeding potential of twelve industrial sugarcane accessions in a humid tropical agroecology of Nigeria. The experiment was laid-out in a randomised complete block design with three replications. Accessions AKWA-005, B70607, C01001, CP65-357, DB37/45 and F141 produced flowers; an indicative trait of their suitability as prospective materials for hybridization. Accession DB37/45 had the highest Brix value of 16.3%, followed by B61208 with 15.7%, accession C01001 had the highest cane yield (58.9 t ha-1) and longest stalks (150 cm); these further highlighted the potentials of C01001, DB37/45, CP65-357, B61208 and AKWA-005 for yield improvement in sugarcane through selection. Whereas principal component and hierarchical cluster analyses (Ward’s method) grouped HAT4, F141 and IMO-002 together, the other accessions formed a separate but distinct grouping. These groupings provided a background information as an aid to selection of similar accessions. Cluster analysis and linear correlation identified significant (P = .05) positive associations between the following traits: stalk girth, stalk length and cane yield. Thus, these traits can be simultaneously selected for and improved in sugarcane. Overall, accession C01001, DB37/45, CP65-357, B61208 and AKWA-005 are recommended for inclusion in the breeding for adaptable lines of sugarcane in the humid tropical agroecology.
Use of Software for Image Analysis and Calibration of Automated Rain Simulator
Authors: Bonfim-Silva Edna Maria , Araújo da Silva Tonny José , De Souza Alves Rackel Danielly , Vieira José Jefferson
Published: April 2019

Aims: To calibrate and evaluate a rain simulator, with automatic operation, as well as determine the average size, the effect of the height of the equipment (2.12; 2.42 and 2.72 m) and of the oscillations of the spray nozzle of the rain simulator (21, 29 and 40 oscillations min-1). Finally, to test and to compare the results of the count of drops by the software of analysis and processing of images Able Image Analyser, ImageJ and Safira.

Study Design: The experimental design was completely randomized, with 3 x 3 x 3 factorial scheme, with three repetitions (81 units).

Place and Duration of Study: The research was conducted in a greenhouse, in the municipality of Rondonópolis, Mato Grosso, located geographically at latitude 16°27'49 "S, longitude       550°34'47" W.

Methodology: For the calibration tests, the rainfall simulator was adjusted according to the heights (2.12; 2.42 and 2.72 m) and oscillations (21, 29 and 40 oscillations min-1), followed by trays with a uniform layer of wheat flour, 2 cm thick, where the simulated raindrops were sprayed for a period of 4 seconds. From this procedure, the drops were dried, sifted, weighed and counted. Droplet analysis was performed using three image analysis software Able Image Analyser, ImageJ and Safira.

Results: The softwares Able Image Analyzer, ImageJ and Safira did not show any significant difference in counting of the number of drops. It was observed that in the oscillation factor in setting that if gets drops of larger size (21 oscillations min-1) the terminal velocity is also greater. In the height factor of the equipment, the drops presented larger sizes at the lower height (2.12 m). There are larger drops, higher terminal velocity as the height of the spray nozzle decreases, and higher kinetic energy value per unit area as the height of the spray nozzle increases. The range of drop sizes observed was 1.2 mm to 3.1 mm.

Conclusion: Although the software does not present significant differences, the ImageJ software proved to be more suitable as a research tool, since it has the license of free use and greater ease of use. Satisfactory results were obtained compared to natural rains in more than one combination of height and swings.
Starvation-induced Changes in Memory Sensitization, Habituation and Psychosomatic Responses
Authors: Ilochi O. N. , Kolawole T. A. , Oluwatayo B. O. , Chuemere A. N.
Published: April 2019

Starvation is a global challenge. Nutritional status of an organism may influence its psychosocial behavior and other nervous system processes like motor responses and its ability to learn and memorize.  This study determined the impact of starvation-induced stress on memory sensitization, habituation and psychosomatic responses in an experimental animal design. 25 wistar rats were randomly sampled and grouped into 1-control, 2- feed after 6 hours deprivation, 3-feed after12 hours deprivation, 4-feed after 18 hours deprivation and 5-feed after 24 hours deprivation. Behavioral tests carried out included the multiple maze tests and elevated plus maze test. Grip strength test was performed to determine neuromuscular response and endurance in all groups. Biochemical investigation of brain stress markers was done on the last day of the study. There was a significant (P≤0.05) enhancement in memory processes and anxiolytic behavior after 6 hours feed deprivation. An increase in antioxidants after 6 hours feed deprivation was suspected to be a compensatory response. A progressive decrease in memory facilitation, anxiolytic behavior and muscular strength was reported after 12, 18 and 24 hours feed deprivation. The increase in habituation and decrease in psychosomatic response was observed and appreciated as the duration of feed deprivation was increased. This study provided evidence about a possible link between memory processes and stress-related alterations in calcium, magnesium and nitric oxide. Starvation may impair learning, memory and motor responses, but this tendency is dependent on the extent of feed deprivation and nutrient depletion.
Nitrogen Fertilization of Marandu Palisadegrass under Different Periods of Deferment
Authors: Loreto Renato Di , De Abreu Joadil Gonçalves , Silva Cabral Luciano da , Behling Neto Arthur , Mendes Ferreira Luis Miguel , Avelino Cabral Carlos Eduardo , De Barros Livia Vieira , De Favare Henrique Guimarães , Herrera Dayenne Mariane , Santos Herrera Larah Drielly
Published: April 2019

The goal with this study was to evaluate the morphological characteristics, nutritive value and the forage dry matter (DM) accumulation of Brachiaria brizantha cv. Marandu in different stages of deferment under nitrogen fertilization levels. The experimental design was a randomized block in split-plot, with three replicates. Plot treatments corresponded to two levels of fertilization (with and without). Split-plot treatments corresponded to four deferment periods (March, April, May, June). Plant height and forage DM accumulation increased (P = .05), while the leaves percentage decreased according to the deferral months. Regarding the fertilization, the percentage of leaves was lower (P= .05) with nitrogen use. The DM content was higher (P = .05) in pastures deferred for a longer time. The neutral detergent fibre (NDF) content increased due to fertilization and greater deferral period. The crude protein (CP) level decreased as the deferral periods. Nitrogen fertilization proved to be viable for the production of good quality forage. The reduction in the deferment period produces forage with better morphological composition and nutritive value.
Gradient Photothermal Field for Precisely Directing Cell Sheet Detachment
Authors: Jing Jiange , Chen Shuangshuang , Lu Qinghua
Published: April 2019

Due to the remaining intact intercellular interactions, cell sheets play increasing roles in biomedical fields. Recently, spatiotemporal control of cell sheets has become an urgent requirement in the context of precise surgery. Here, the development of a gradient photothermal biointerface for precisely directing cell sheet detachment through quantitatively regulating the dissociation rate of collagen is reported. This novel and facile method shows great potential for application in precise regenerative medicine.
Bi‐Facial Substrates Enabled Heterogeneous Multi‐Dimensional Integrated Circuits (MD‐IC) for Internet of Things (IoT) Applications
Authors: El‐Atab Nazek , Shaikh Sohail F. , Khan Sherjeel M. , Hussain Muhammad M.
Published: April 2019

The primary focus of modern electronics technology is to increase its functionalities within a smaller footprint at an affordable cost. This creates a new set of design challenges for the already‐existing complex integration and packaging schemes. Here, CMOS‐compatible and heterogeneous multi‐dimensional integrated circuits (MD‐IC) as smart electronic systems for Internet of Things (IoT) applications are shown. Both sides of bulk monocrystalline Si (100) substrate for device fabrication which are connected via through‐silicon‐via to transform it into bi‐facial CMOS electronics system are used. As a proof‐of‐concept, cubic, pyramidal, and buckyball shaped MD‐ICs, with broad variety of devices including humidity, temperature, pressure, and pH sensors, solar cells, antenna, microcontroller, light emitting diode and micro lithium‐ion battery are shown. In these MD‐ICs, adjacent sides are interconnected through side‐interlocks. It is also shown that polymeric encapsulation and heterogeneous materials (Si, Ge, and GaSb) can be integrated in the MD‐IC architecture to meet the rigorous requirements of IoT devices. Compared to folded rigid or flexible Printed Circuit Board based electronics, this report shows unprecedented usage of area by device fabrication on both sides which are also connected through‐silicon‐via as state‐of‐the‐art tool for 3D‐IC manufacturing.
Direct 3D Printing of Stretchable Circuits via Liquid Metal Co‐Extrusion Within Thermoplastic Filaments
Authors: Khondoker Mohammad A. H. , Ostashek Adam , Sameoto Dan
Published: April 2019

Liquid‐metal alloys are now extensively used for stretchable electronic applications due to their superior electrical conductivity, non‐toxicity, and mechanical stability in micro‐channels. Needle‐injection and direct‐writing are the most popular techniques for patterning micro‐structured liquid metal alloys. However, embedded channels often require a very high pressure to inject liquid‐metal, and direct writing by dispensing is relatively complex due to the low viscosities and high surface tension of the metal which cause liquid to normally dispense in droplets rather than a stream. In this work, a technique to co‐axially extrude liquid‐metal alloy within an encapsulating cover fluid has been presented to obtain a continuous stable stream of liquid‐metal. Fused deposition modeling (FDM) 3D printing has been adapted to co‐extrude a liquid‐metal core with a shell made from a thermoplastic elastomer. A custom extruder system is used to directly produce conductive micro‐wires (diameter: ≈25 μm) of liquid‐metal having an insulating shell of styrene‐ethylene‐butylene‐styrene which can be stretched up to four times the original length without any noticeable mechanical and electrical loss. The system is capable of printing in‐plane conductive pathways as well as out‐of‐plane functional devices with direct‐stable encapsulation of liquid‐metal wires. This technology has been successfully used to print 2D‐pressure and 3D‐strain sensors.
Controlled Fabrication of 3D Chiral Microwrinkles via Asymmetrical and Biaxial Bucklings
Authors: Hwang Myonghoo , Kim Changho , Kim Jinwoo , Son Jeong Gon , Yeom Bongjun
Published: April 2019

Nano‐ and microsized chiral materials are receiving significant attention because of their unique characteristics, which include chiroptical activities and enantioselective interactions with living materials. However, the realization of chiral morphologies in such small‐scale materials has been an issue because of the complicated fabrication methods and limited material selection. In this study, a facile and reproducible method is developed for fabricating 3D chiral microwrinkles with twisted shapes by asymmetric and biaxial buckling. Soft polydimethylsiloxane (PDMS) substrates are asymmetrically stretched with angled biaxial strains and exposed to UV/ozone to prepare hard silica layers on top of the PDMS substrates to induce microwrinkles. The chiral shapes are controlled by changing the angle (θ) between the two strain axes and the UV/ozone exposure times (t1, t2) in each stage of buckling. The 3D chiral microwrinkles are shaped like “fusilli pasta” and occupy an area of 1.5 cm × 1.5 cm. The patterned area can be easily scaled, and no innate chiral biomaterial is necessary. This method could be widely extended to the fabrication of diverse types of chiral materials for advanced optical and bio‐applications.
Hole Transport Materials Based on 6,12‐Dihydroindeno[1,2‐b]fluorine with Different Periphery Groups: A New Strategy for Dopant‐Free Perovskite Solar Cells
Authors: Liu Fan , Wu Fei , Tu Zongxiao , Liao Qiuyan , Gong Yanbin , Zhu Linna , Li Qianqian , Li Zhen
Published: April 2019

Although several hole‐transporting materials (HTMs) have been designed to obtain perovskite solar cells (PSCs) devices with high performance, the dopant‐free HTMs for efficient and stable PSCs remain rare. Herein, a rigid planar 6,12‐dihydroindeno[1,2‐b]fluorine (IDF) core with different numbers of bulky periphery groups to construct dopant‐free HTMs of IDF‐SFXPh, IDF‐DiDPA, and IDF‐TeDPA is modified. Thanks to the contributions of the planar IDF core and the twisted SFX periphery groups, the dopant‐free IDF‐SFXPh‐based PSCs device achieves a device performance of 17.6%, comparable to the doped 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD)‐based device (17.6%), with much enhanced device stability under glovebox and ambient conditions.
Zr‐Doped Indium Oxide (IZRO) Transparent Electrodes for Perovskite‐Based Tandem Solar Cells
Authors: Aydin Erkan , De Bastiani Michele , Yang Xinbo , Sajjad Muhammad , Aljamaan Faisal , Smirnov Yury , Hedhili Mohamed Nejib , Liu Wenzhu , Allen Thomas G. , Xu Lujia , Van Kerschaver Emmanuel , Morales‐Masis Monica , Schwingenschlögl Udo , De Wolf Stefaan
Published: April 2019

Parasitic absorption in transparent electrodes is one of the main roadblocks to enabling power conversion efficiencies (PCEs) for perovskite‐based tandem solar cells beyond 30%. To reduce such losses and maximize light coupling, the broadband transparency of such electrodes should be improved, especially at the front of the device. Here, the excellent properties of Zr‐doped indium oxide (IZRO) transparent electrodes for such applications, with improved near‐infrared (NIR) response, compared to conventional tin‐doped indium oxide (ITO) electrodes, are shown. Optimized IZRO films feature a very high electron mobility (up to ≈77 cm2 V−1 s−1), enabling highly infrared transparent films with a very low sheet resistance (≈18 Ω □−1 for annealed 100 nm films). For devices, this translates in a parasitic absorption of only ≈5% for IZRO within the solar spectrum (250–2500 nm range), to be compared with ≈10% for commercial ITO. Fundamentally, it is found that the high conductivity of annealed IZRO films is directly linked to promoted crystallinity of the indium oxide (In2O3) films due to Zr‐doping. Overall, on a four‐terminal perovskite/silicon tandem device level, an absolute 3.5 mA cm−2 short‐circuit current improvement in silicon bottom cells is obtained by replacing commercial ITO electrodes with IZRO, resulting in improving the PCE from 23.3% to 26.2%.
Superamphiphobic Porous Structure: Design and Implementation
Authors: Li Fang , Du Miao , Xiao Jianliang , Cao Can , Xia Xueke , Xie Jian , Zhao Xinbing , Song Yihu , Zheng Qiang
Published: April 2019

Porous materials with an excellent super‐repellency exist in many applications in life and industry, and their preparation is convenient and cost effective. It would be advantageous to fabricate super‐repellent porous materials. However, because of a lack of understanding of the detailed relationship between structural features and super‐repellency, it is difficult to prepare porous materials with a superamphiphobicity. Based on a theoretical analysis and the discussion of several porous structures' repellant behaviors, the criteria for fabricating super‐repellent porous materials are proposed as: (1) the most appropriate pore size being tens of micrometers to ≈100–200 µm; (2) a larger pore height; (3) a smaller porous‐network thickness; and (4) an appropriate adequate secondary microscopic structure that favors the effective pinning of a gas–liquid–solid three‐phase contact line. According to the four criteria, an optimized superamphiphobic porous material is achieved, which is a dopamine/redox graphene‐oxide‐assembled microscale porous material, which displays a super‐repellency for droplets with a surface tension of 72.8–20 mN m−1. By using the dopamine/graphene‐assembled microscale porous material, a low gate voltage (500 V) for water impaling is acquired.
SBA‐15/POSS‐Imidazolium Hybrid as Catalytic Nanoreactor: the role of the Support in the Stabilization of Palladium Species for C−C Cross Coupling Reactions.
Authors: Calabrese Carla , Campisciano Vincenzo , Siragusa Fabiana , Liotta Leonarda F. , Aprile Carmela , Gruttadauria Michelangelo , Giacalone Francesco
Published: April 2019

Supported imidazolium modified polyhedral oligomeric silsesquioxanes (POSS) on SBA‐15 have been used as platform for Pd(II) species. The so‐obtained material was firstly characterized by means of TGA, solid state NMR, TEM, XPS, SAXS, porosimetry and ICP‐OES and it was successfully tested as pre‐catalyst in C−C cross couplings, namely Suzuki‐Miyaura and Heck reactions. In both cases, the solid proved to be highly efficient and easily recoverable from the reaction mixture. The recyclability was verified for up to seven cycles without showing any activity decrease. Interestingly, only Pd(II) was detected in the reused catalyst in the Heck reaction. Therefore, the versatility of the material was investigated by using various aryl halides. Our palladium nanocomposite was able to promote both Suzuki and Heck reactions down to 0.0007 mol% showing outstanding turnover frequency (TOF) values of 114,286 and 32,381 h−1, respectively. Comparison with the palladium catalyst on SiO2‐POSS‐imidazolium support showed interesting differences in terms of stabilization of Pd species and recyclability. The excellent outcome of the reactions could be ascribed to the textural properties of the SBA‐15 support and the presence of the imidazolium‐POSS nanocage within the pores of SBA‐15, that worked as a sort of nanoreactor.

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Macrophages‐Triggered Sequential Remodeling of Endothelium‐Interstitial Matrix to Form Pre‐Metastatic Niche in Microfluidic Tumor Microenvironment
Authors: Kim Hyunho , Chung Hyewon , Kim Jaehoon , Choi Dong‐Hee , Shin Yoojin , Kang Yong Guk , Kim Beop‐Min , Seo Sang‐Uk , Chung Seok , Seok Seung Hyeok
Published: April 2019

The primed microenvironment of future metastatic sites, called the pre‐metastatic niche, is a prerequisite for overt metastasis. However, a mechanistic understanding of the contributions of recruited cells to the niche is hindered by complex in vivo systems. Herein, a microfluidic platform that incorporates endothelial cells and extracellular matrix (ECM) scaffolds is developed, and the distinct role of recruited monocytes and macrophages in establishing pre‐metastatic niches is delineated. It is observed that monocyte‐derived matrix metalloproteinase 9 facilitates cancer cell extravasation through destruction of endothelial tight junctions. Furthermore, subsequent cancer cell invasiveness is significantly enhanced. Close examination of ECM structures reveals that cancer cells move within characteristic “microtracks” generated by macrophages, suggesting that macrophages could serve as a compensatory mechanism for the reduced migratory capacity of cancer cells. Thus, the first evidence of monocyte/macrophage‐induced remodeling is shown, and these findings will open up new horizons for improving characterization of the pre‐metastatic niche and corresponding immunotherapies.
A New Mode of Chemical Reactivity for Metal‐Free Hydrogen Activation by Lewis Acidic Boranes
Authors: Bennett Elliot L. , Lawrence Elliot J. , Blagg Robin J. , Mullen Anna S. , MacMillan Fraser , Ehlers Andreas W. , Scott Daniel J. , Sapsford Joshua S. , Ashley Andrew E. , Wildgoose Gregory G. , Slootweg J. Chris
Published: April 2019

We herein explore whether tris(aryl)borane Lewis acids are capable of cleaving H2 outside of the usual Lewis acid/base chemistry described by the concept of frustrated Lewis pairs (FLPs). Instead of a Lewis base we use a chemical reductant to generate stable radical anions of two highly hindered boranes: tris(3,5‐dinitromesityl)borane and tris(mesityl)borane. NMR spectroscopic characterization reveals that the corresponding borane radical anions activate (cleave) dihydrogen, whilst EPR spectroscopic characterization, supported by computational analysis, reveals the intermediates along the hydrogen activation pathway. This radical‐based, redox pathway involves the homolytic cleavage of H2, in contrast to conventional models of FLP chemistry, which invoke a heterolytic cleavage pathway. This represents a new mode of chemical reactivity for hydrogen activation by borane Lewis acids.
Formation of Twinned Graphene Polycrystals
Authors: Dong Jichen , Geng Dechao , Liu Fengning , Ding Feng
Published: April 2019

Liquid metals have been widely used as substrates to grow graphene and other 2D materials. On a homogeneous and isotropic liquid surface, a polycrystalline 2D material is formed by coalescence of many randomly nucleated single‐crystal islands, and as a result, the domains in a polycrystal are expected to be randomly aligned. Here, we report the unexpected finding that only 30°‐twinned graphene polycrystals are grown on a liquid Cu surface. Atomic simulations confirm that the unique domain alignment in graphene polycrystals is due to the free rotation of graphene islands on the liquid Cu surface and the highly stable 30°‐grain boundaries in graphene. In‐depth analysis predicts 30 types of possible 30°‐twinned graphene polycrystals and 27 of them are observed. The revealed formation mechanism of graphene polycrystals on a liquid Cu surface deepens our fundamental understanding on polycrystal growth and could serve as a guideline for the controlled synthesis of 2D materials.
Electrochemical Monitoring of ROS/RNS Homeostasis Within Individual Phagolysosomes Inside Single Macrophages
Authors: Zhang Xin‐Wei , Oleinick Alexander , Jiang Hong , Liao Quan‐Lan , Qiu Quan‐Fa , Svir Irina , Liu Yan‐Ling , Amatore Christian , Huang Wei‐Hua
Published: April 2019

The existence of a homeostatic mechanism regulating reactive oxygen/nitrogen species (ROS/RNS) amounts inside phagolysosomes has been invoked to account for the efficiency of this process but could not be unambiguously documented. Now, intracellular electrochemical analysis with platinized nanowire electrodes (Pt‐NWEs) allowed monitoring ROS/RNS effluxes with sub‐millisecond resolution from individual phagolysosomes impacting onto the electrode inserted inside a living macrophage. This shows for the first time that the consumption of ROS/RNS by their oxidation at the nanoelectrode surface stimulates the production of significant ROS/RNS amounts inside phagolysosomes. These results establish the existence of the long‐postulated ROS/RNS homeostasis and allows its kinetics and efficiency to be quantified. ROS/RNS concentrations may then be maintained at sufficiently high levels for sustaining proper pathogen digestion rates without endangering the macrophage internal structures.
Tautomer‐Specific Resonant Photoelectron Imaging of Deprotonated Cytosine Anions
Authors: Zhu Guo‐Zhu , Qian Chen‐Hui , Wang Lai‐Sheng
Published: April 2019

Tautomers of the nucleobases play fundamental roles in spontaneous mutations of DNA. Tautomers of neutral cytosine have been studied in the gas phase, but much less is known about charged species. Here, we report the observation and characterization of three tautomers of deprotonated cytosine anions, [trans‐keto‐amino‐N3H‐H8b] (tKAN3H8b−), [cis‐keto‐amino‐N3H‐H8a] (cKAN3H8a−) and [keto‐amino‐H] (KAN1−), produced by electrospray ionization. Excited dipole‐bound states (DBSs) are uncovered for the three anions by photodetachment spectroscopy. Excitations to selected DBS vibrational levels of cKAN3H8a− and tKAN3H8b− yield tautomer‐specific resonant photoelectron spectra. The current study provides further insight into tautomerism of cytosine and suggests a new method to study the tautomers of nucleobases using electrospray ionization and anion spectroscopy.
Der Naturstoff Elegaphenon verstärkt antibiotische Effekte gegen Pseudomonas aeruginosa
Authors: Zhao Weining , Cross Ashley R. , Crowe‐McAuliffe Caillan , Weigert‐Munoz Angela , Csatary Erika E. , Solinski Amy E. , Krysiak Joanna , Goldberg Joanna B. , Wilson Daniel N. , Medina Eva , Wuest William M. , Sieber Stephan A.
Published: April 2019

Naturstoffe sind eine ergiebige Quelle für Antibiotika, die vielfältige zelluläre Zielstrukturen adressieren. Die Erforschung ihrer Zielproteine mittels chemischer Proteomik wird häufig durch das Einbringen sterisch anspruchsvoller photoreaktiver Gruppen erschwert. Hier verwenden wir Elegaphenon, ein weitestgehend uncharakterisiertes Naturstoffantibiotikum mit einem nativen Benzophenongrundgerüst für affinitätsbasiertes Protein Profiling (AfBPP) in grampositiven und gramnegativen Bakterien. In dieser Studie wurde das Naturstoffgerüst alkinyliert und als Sonde verwendet wodurch es gelungen ist, den Transkriptionsregulator AlgP als biologisches Angriffsziel aufzudecken. Weiterhin wurden durch Proteomprofiling einer Pseudomoas aeruginosa AlgP‐Transposonmutanten einzigartige Erkenntnisse über den Wirkmechanismus gewonnen. Elegaphenon verstärkt die Eliminierung intrazellulärer P. aeruginosa in Makrophagen bei Behandlung mit dem Fluorchinolonantibiotikum Norfloxacin in subinhibitorischen Konzentrationen.
The Structure of the Elusive Urease–Urea Complex Unveils the Mechanism of a Paradigmatic Nickel‐Dependent Enzyme
Authors: Mazzei Luca , Cianci Michele , Benini Stefano , Ciurli Stefano
Published: April 2019

Urease, the most efficient enzyme known, contains an essential dinuclear NiII cluster in the active site. It catalyzes the hydrolysis of urea, inducing a rapid pH increase that has negative effects on human health and agriculture. Thus, the control of urease activity is of utmost importance in medical, pharmaceutical, and agro‐environmental applications. All known urease inhibitors are either toxic or inefficient. The development of new and efficient chemicals able to inhibit urease relies on the knowledge of all steps of the catalytic mechanism. The short (microseconds) lifetime of the urease–urea complex has hampered the determination of its structure. The present study uses fluoride to substitute the hydroxide acting as the co‐substrate in the reaction, preventing the occurrence of the catalytic steps that follow substrate binding. The 1.42 Å crystal structure of the urease–urea complex, reported here, resolves the enduring debate on the mechanism of this metalloenzyme.
Acyl Fluorides in Late‐Transition‐Metal Catalysis
Authors: Ogiwara Yohei , Sakai Norio
Published: April 2019

In this Review, we summarize the current state of the art in late‐transition‐metal‐catalyzed reactions of acyl fluorides, covering both their synthesis and further transformations. In organic reactions, the relationship between stability and reactivity of the starting substrates is usually characterized by a trade‐off. Yet, acyl fluorides display a very good balance between these properties, which is mostly due to their moderate electrophilicity. Thus, acyl fluorides (RCOF) can be used as versatile building blocks in transition‐metal‐catalyzed reactions, for example, as an “RCO” source in acyl coupling reactions, as an “R” source in decarbonylative coupling reactions, and as an “F” source in fluorination reactions. Starting from the cleavage of the acyl C−F bond in acyl fluorides, various transformations are accessible, including C−C, C−H, C−B, and C−F bond‐forming reactions that are catalyzed by transition‐metal catalysts that contain the Group 9–11 metals Co, Rh, Ir, Ni, Pd, or Cu.
Catalytic Enantioselective Intermolecular Benzylic C(sp3)−H Amination
Authors: Nasrallah Ali , Boquet Vincent , Hecker Alexandra , Retailleau Pascal , Darses Benjamin , Dauban Philippe
Published: April 2019

A practical general method for asymmetric intermolecular benzylic C(sp3)−H amination has been developed by combining the pentafluorobenzyl sulfamate PfbsNH2 with the chiral rhodium(II) catalyst Rh2(S‐tfptad)4. Various substrates can be used as limiting components and converted to benzylic amines with excellent yields and high levels of enantioselectivity. Additional key features for the reaction are the low catalyst loading and the ability to remove the Pfbs group under mild conditions to give NH‐free benzylic amines.
The Effects of Matrigel® on the Survival and Differentiation of a Human Neural Progenitor Dissociated Sphere Culture
Authors: Kaiser Andreas , Kale Ajay , Novozhilova Ekaterina , Olivius Petri
Published: April 2019

We have previously developed an in vitro organotypic culture setting in order to investigate the performance of cellular substrates transplanted to the auditory nervous system. We have utilized this system to predict the efficacy of human neural progenitor cells (HNPCs) in transplantation to the auditory nerve to facilitate regeneration of sensory auditory nerve structures in vivo and in vitro. To optimize the growth and differentiation of HNPCs we have introduced an expansion of our in vitro system, exploring the impact of a growth factor‐altered microenvironment. Here, we seeded HNPCs as a dissociated sphere culture on a hydrogel matrix coating (Matrigel®). We evaluated the performance of HNPCs by studying their survival, differentiation, and their axon‐forming capacity. In identical culture conditions, we found that the overall survival rate of HNPCs on Matrigel coated surfaces was better than that on surfaces that were not coated with Matrigel. Furthermore, cells on Matrigel differentiated into neuronal cells to a far greater extent leading to strong synaptic marker signatures. Overall, our findings show that the present Matrigel matrix setting offers an experimental environment for the HNPCs to grow where these cells show novel and promising phenotypic characteristics suitable for further in vivo transplantation to the auditory nerve. Anat Rec, 303:441–450, 2020. © 2019 American Association for Anatomy
Maternal diabetes and hypertensive disorders in association with autism spectrum disorder
Authors: Cordero Christina , Windham Gayle C. , Schieve Laura A. , Fallin Margaret Daniele , Croen Lisa A. , Siega‐Riz Anna Maria , Engel Stephanie M. , Herring Amy H. , Stuebe Alison M. , Vladutiu Catherine J. , Daniels Julie L.
Published: April 2019

Previous studies have shown complications of pregnancy, often examined in aggregate, to be associated with autism spectrum disorder (ASD). Results for specific complications, such as maternal diabetes and hypertension, have not been uniformly consistent and should be investigated independently in relation to ASD in a large community‐based sample. The Study to Explore Early Development (SEED), a US multisite case–control study, enrolled children born in 2003–2006 at 2–5 years of age. Children were classified into three groups based on confirmation of ASD (n = 698), non‐ASD developmental delay (DD; n = 887), or controls drawn from the general population (POP; n = 979). Diagnoses of any diabetes or hypertensive disorder during pregnancy were identified from prenatal medical records and maternal self‐report. Logistic regression models estimated adjusted odds ratios (aOR) and confidence intervals (CI) adjusting for maternal age, race/ethnicity, education, smoking during pregnancy, and study site. Models for hypertension were additionally adjusted for parity and plurality. Among 2,564 mothers, we identified 246 (9.6%) with any diabetes and 386 (15.1%) with any hypertension in pregnancy. After adjustment for covariates, any diabetes during pregnancy was not associated with ASD (aOR = 1.10 [95% CI 0.77, 1.56]), but any hypertension was associated with ASD (aOR = 1.69 [95% CI 1.26, 2.26]). Results were similar for DD, and any diabetes (aOR = 1.29 [95% CI 0.94, 1.78]) or any hypertension (aOR = 1.71 [95% CI 1.30, 2.25]). Some pregnancy complications, such as hypertension, may play a role in autism etiology and can possibly serve as a prompt for more vigilant ASD screening efforts. Autism Res 2019, 12: 967–975. © 2019 International Society for Autism Research, Wiley Periodicals, Inc.

Lay Summary

We studied if common complications in pregnancy are associated with autism spectrum disorder (ASD) in a large sample of mothers and children. Our results show an association between conditions marked by high blood pressure and ASD, but no association with conditions marked by high blood sugar and ASD. Associations were similar for children who had a developmental disorder that was not ASD, suggesting that this relationship may not be specific to ASD.
Targeting the Spleen as an Alternative Site for Hematopoiesis
Authors: Short Christie , Lim Hong K. , Tan Jonathan , O'Neill Helen C.
Published: April 2019

Bone marrow is the main site for hematopoiesis in adults. It acts as a niche for hematopoietic stem cells (HSCs) and contains non‐hematopoietic cells that contribute to stem cell dormancy, quiescence, self‐renewal, and differentiation. HSC also exist in resting spleen of several species, although their contribution to hematopoiesis under steady‐state conditions is unknown. The spleen can however undergo extramedullary hematopoiesis (EMH) triggered by physiological stress or disease. With the loss of bone marrow niches in aging and disease, the spleen as an alternative tissue site for hematopoiesis is an important consideration for future therapy, particularly during HSC transplantation. In terms of harnessing the spleen as a site for hematopoiesis, here the remarkable regenerative capacity of the spleen is considered with a view to forming additional or ectopic spleen tissue through cell engraftment. Studies in mice indicate the potential for such grafts to support the influx of hematopoietic cells leading to the development of normal spleen architecture. An important goal will be the formation of functional ectopic spleen tissue as an aid to hematopoietic recovery following clinical treatments that impact bone marrow. For example, expansion or replacement of niches could be considered where myeloablation ahead of HSC transplantation compromises treatment outcomes.
Why the Lipid Divide? Membrane Proteins as Drivers of the Split between the Lipids of the Three Domains of Life
Authors: Sojo Victor
Published: April 2019

Recent results from engineered and natural samples show that the starkly different lipids of archaea and bacteria can form stable hybrid membranes. But if the two types can mix, why don't they? That is, why do most bacteria and all eukaryotes have only typically bacterial lipids, and archaea archaeal lipids? It is suggested here that the reason may lie on the other main component of cellular membranes: membrane proteins, and their close adaptation to the lipids. Archaeal lipids in modern bacteria could suggest that the last universal common ancestor (LUCA) had both lipid types. However, this would imply a rather elaborate evolutionary scenario, while negating simpler alternatives. In light of widespread horizontal gene transfer across the prokaryotic domains, hybrid membranes reveal that the lipid divide did not just occur once at the divergence of archaea and bacteria from LUCA. Instead, it continues to occur actively to this day. Also see the video abstract here https://youtu.be/TdKjxoDAtsg.
Decision Tree‐PLS (DT‐PLS) algorithm for the development of process: Specific local prediction models
Authors: Narayanan Harini , Sokolov Michael , Butté Alessandro , Morbidelli Massimo
Published: April 2019

This work presents a novel multivariate statistical algorithm, Decision Tree‐PLS (DT‐PLS), to improve the prediction and understanding of dynamic processes based on local partial least square regression (PLSR) models for characteristic process groups defined based on Decision Tree (DT) analysis. The DT‐PLS algorithm is successfully applied to two different cell culture data sets, one obtained from bioreactors of 3.5 L lab scale and the other obtained from the 15 ml ambr microbioreactor system. Substantial improvement in the predictive capabilities of the model can be achieved based on the localization compared to the classical PLSR approach, which is implemented in the commercially available packages. Additionally, the differences in the model parameters of the local models suggest that the governing process variables vary for the different process regimes indicating the different states of the cell under different process conditions.
Bridge the gap between security, disability services through partnerships
Authors: Sutton Halley
Published: April 2019

According to a report published by the Ruderman Family Foundation, almost half of people killed by police have some form of disability. In a webinar hosted by the Bureau of Justice Assistance and the Vera Institute of Justice, panelists discussed ways law enforcement agencies can partner with others to build resources for preventing crises involving individuals with disabilities and de‐escalating potentially fraught scenarios safely.
Be proactive to ensure safety of campus community
Authors: Hope Joan
Published: April 2019

Sometimes your best efforts as a police chief can't be measured — because they prevent crime and injuries, and you don't know what would have happened without them. Scott Borden, chief of police at Rio Grande Community College and the University of Rio Grande in Ohio, takes a proactive approach to keeping his campus safe.
NAC for cannabis use disorder and depression
Authors: Duncan Alison
Published: April 2019

Case: A 16‐year‐old patient is referred for major depressive disorder and cannabis use disorder (CUD). In the past year, she has been smoking marijuana three to five times per day, every day. Over the same year, her grades have declined and her relationship with her family has been strained in the context of increased cannabis use. Sertraline was started 4 months ago for depression and has been dosed at 200 mg daily for the past month. Her family notes improvement in sleep, concentration and mood with the selective serotonin reuptake inhibitor. The patient describes using marijuana, “because it's the only thing that has worked for my anxiety and made me not care about my depression.” She describes craving marijuana every day, especially when she smells marijuana on her clothes, smells marijuana on someone else, hears a song on the radio that she has enjoyed while high, or sees images of people smoking on TV. She doesn't intend to stop smoking altogether, but she doesn't want to feel like she needs to smoke every day. She has a history of occasional alcohol use (less than once a month) and occasional cigarettes (less than five per week).
Mixed aortic valve disease treated with transcatheter aortic valve replacement in a high risk patient presenting with acute decompensated heart failure
Authors: Raj Leah , Mehra Anilkumar , Shavelle David M.
Published: April 2019

Mixed aortic valve disease refers to the combination of aortic regurgitation (AR) and aortic stenosis (AS). Commonly etiologies include a bicuspid aortic valve, rheumatic heart disease, and endocarditis superimposed upon a stenotic aortic valve. Treatment depends upon the severity of disease, the presence of symptoms and the size and function of the left ventricle. We present a case of a young patient that presented with new onset acute decompensated heart failure with mixed aortic valve disease that was successful treated with transcatheter aortic valve replacement (TAVR). Invasive hemodynamics at baseline and following TAVR provide an insight into the characteristic features of mixed aortic valve disease. TAVR represents a new treatment option for critically ill patients deemed high risk or nonoperable for surgical aortic valve replacement.
Improved Ion‐Transfer Behavior and Capacitive Energy Storage Characteristics of SnO2 Nanospacer‐Incorporated Reduced Graphene Oxide Electrodes
Authors: Noh Yuseong , Kim Yoongon , Han Hyunsu , Jung Wan‐Gil , Kim Jong Guk , Kim Youngmin , Kim Hyung Ju , Kim Bong‐Joong , Kim Won Bae
Published: April 2019

This report demonstrates the modification of reduced graphene oxide (RGO) nanosheets by decorating SnO2 nanorod bundles and nanoparticles on the surface for effective use of the graphene as supercapacitor electrode materials. The shape‐ and density‐controlled SnO2 nanostructures were prepared through hydrothermal synthesis and acted as spacer materials to physically inhibit the overlapping of the RGO sheets; this is known as the restacking effect. When measuring the electrochemical properties, the electrode comprising RGO with SnO2 nanorod bundles (RGO−SnO2−NR) revealed a higher capacitance, rate capability, and cyclic stability than the RGO electrode with SnO2 nanoparticles (RGO−SnO2−NP) and the bare RGO electrode, indicating the effective role of the surface‐implanted SnO2 spacer during the electrode reactions of the double‐layer capacitor. The electrochemical superiority of RGO−SnO2−NR could be explained by the fact that wedge‐like SnO2 nanorod bundles between the RGO sheets promote fast transfer and approach of electroactive species to form the electrochemical double layer at the electrode surface. Moreover, the improved mass transfer behavior of the RGO−SnO2 composite electrodes and the role of the SnO2 nanostructures were reasonably verified by various electrochemical analyses.
Hückel and Möbius Aromaticity in Charged Sigma Complexes
Authors: Mauksch Michael , Tsogoeva Svetlana B.
Published: April 2019

In sigma complexes, intermediates in nucleophilic and electrophilic aromatic substitution and other reactions, delocalization in the aromatic ring is formally disrupted. Unexpectedly, computational evidence is presented that favorable processes contain aromatic sigma complexes. Tetracoordinated carbon therein surprisingly employs orbitals that are more similar to sp2 than to sp3 hybrids in sigma bonds with adjacent ring atoms. Both leaving groups and nucleo‐ or electrophiles may donate electrons to the π‐system depending on the availability of p‐type orbitals to fulfill Hückel (4N+2) or Möbius (4N) rules of aromaticity in analogy to conjugated transition‐metal metallacycles.
Hydrazide–Hydrazone Small Molecules as AIEgens: Illuminating Mitochondria in Cancer Cells
Authors: Patil Sohan , Pandey Shalini , Singh Amit , Radhakrishna Mithun , Basu Sudipta
Published: April 2019

Aggregation‐induced‐emission luminogens (AIEgens) have gained considerable attention as interesting tools for several biomedical applications, especially for bioimaging due to their brightness and photostability. Numerous AIEgens have been developed for lighting up the subcellular organelles to understand their forms and functions not only healthy but also unhealthy states, such as in cancer cells. However, there is lack of easily synthesizable, biocompatible small molecules for illuminating mitochondria (powerhouses) inside cells. To address this issue, an easy and short synthesis of new biocompatible hydrazide–hydrazone‐based small molecules with remarkable aggregation‐induced emission (AIE) properties is described. These small‐molecule AIEgens showed hitherto unobserved AIE properties due to dual intramolecular H‐bonding confirmed by theoretical calculation, pH‐ and temperature‐dependent fluorescence and X‐ray crystallographic studies. Confocal microscopy showed that these AIEgens were internalized into the HeLa cervical cancer cells without showing any cytotoxicity. One of the AIEgens was tagged with a triphenylphosphine (TPP) moiety, which successfully localized in the mitochondria of HeLa cells in a selective way compared to L929 noncancerous fibroblast cells. These unique hydrazide–hydrazone‐based biocompatible AIEgens can serve as powerful tools to illuminate multiple subcellular organelles to elucidate their forms and functions in cancer cells for next‐generation biomedical applications.
1,3,9‐Triaza‐2‐oxophenoxazine: An Artificial Nucleobase Forming Highly Stable Self‐Base Pairs with Three AgI Ions in a Duplex
Authors: Fujii Akane , Nakagawa Osamu , Kishimoto Yuki , Okuda Takumi , Nakatsuji Yusuke , Nozaki Natsumi , Kasahara Yuuya , Obika Satoshi
Published: April 2019

Invited for the cover of this issue is the group of Osamu Nakagawa and Satoshi Obika at Osaka University. The image depicts a DNA double helix structure dynamically constructed by incorporation of silver ions into 9‐TAP self‐base pairs. Read the full text of the article at 10.1002/chem.201900373.