bluuebunny/crossref_metadata_2025 huggingface dataset:
Lagrangian and Eulerian Description of Bed Load Transport
Authors: Ballio Francesco , Pokrajac Dubravka , Radice Alessio , Hosseini Sadabadi Seyed Abbas
Published: February 2018

Sediment particles transported as bed load undergo alternating periods of motion and rest, particularly at weak flow intensity. Bed load transport can be investigated by either following the motion of individual particles (Lagrangian approach) or observing the phenomenon at prescribed locations (Eulerian approach). In this paper, the Lagrangian and Eulerian descriptions are merged into a unifying framework that includes definitions for quantities used to describe the kinematics of particle motion, as well as the relationships among these quantities. The alternation of motion and rest is represented by two complementary descriptions: (i) proportion of motion, indicating either the relative time spent in motion by an individual particle or the relative number of moving particles; (ii) persistence of motion, indicating the extent to which the process consists of relatively few long periods of motion or of many short ones. The framework only involves first moments of the key quantities. The conceptual developments are tested against results from an experiment with weak bed load transport, demonstrating the soundness of the approach. From an operational point of view, a Lagrangian observation is difficult to perform, since the particle motion is usually investigated for finite spatial domains (e.g., a measurement window within a laboratory or natural reach). Strategies to overcome such limitations are described, suggesting the possibility of obtaining unbiased mean values for Lagrangian descriptors. The proposed framework can be used in any study aimed at parameterizing the kinematic properties of bed load particles as functions of the hydrodynamic conditions.
Climate Change Attribution: When Is It Appropriate to Accept New Methods?
Authors: Lloyd Elisabeth A. , Oreskes Naomi
Published: February 2018

The most common approaches to detection and attribution (D&A) of extreme weather events using fraction of attributable risk or risk ratio answer a particular form of research question, namely “What is the probability of a certain class of weather events, given global climate change, relative to a world without?” In a set of recent papers, Trenberth et al. (2015,https://doi.org/10.1038/nclimate2657) and Shepherd (2016,https://doi.org/10.1007/s40641‐016‐0033‐y) have argued that this is not always the best tool for analyzing causes, or for communicating with the public about climate events and extremes. Instead, they promote the idea of a “storyline” approach, which asks complementary questions, such as “How much did climate change affect the severity of a given storm?” From the vantage of history and philosophy of science, a proposal to introduce a new approach or to answer different research questions—especially those of public interest—does not appear particularly controversial. However, the proposal proved highly controversial, with the majority of D&A scientists reacting in a very negative and even personal manner. Some suggested the proposed alternatives amount to a weakening of standards, or an abandonment of scientific method. Here, we address the question: Why is this such a controversial proposition? We argue that there is no “right” or “wrong” approach to D&A in any absolute sense, but rather that in different contexts, society may have a greater or lesser concern with errors of a particular type. How we view the relative risk of overestimation versus underestimation of harm is context‐dependent.
Biogeophysical Impacts of Land‐Use Change on Climate Extremes in Low‐Emission Scenarios: Results From HAPPI‐Land
Authors: Hirsch Annette L. , Guillod Benoit P. , Seneviratne Sonia I. , Beyerle Urs , Boysen Lena R. , Brovkin Victor , Davin Edouard L. , Doelman Jonathan C. , Kim Hyungjun , Mitchell Daniel M. , Nitta Tomoko , Shiogama Hideo , Sparrow Sarah , Stehfest Elke , van Vuuren Detlef P. , Wilson Simon
Published: February 2018

The impacts of land use have been shown to have considerable influence on regional climate. With the recent international commitment to limit global warming to well below 2°C, emission reductions need to be ambitious and could involve major land‐use change (LUC). Land‐based mitigation efforts to curb emissions growth include increasing terrestrial carbon sequestration through reforestation, or the adoption of bioenergy crops. These activities influence local climate through biogeophysical feedbacks, however, it is uncertain how important they are for a 1.5° climate target. This was the motivation for HAPPI‐Land: the half a degree additional warming, prognosis, and projected impacts—land‐use scenario experiment. Using four Earth system models, we present the first multimodel results from HAPPI‐Land and demonstrate the critical role of land use for understanding the characteristics of regional climate extremes in low‐emission scenarios. In particular, our results show that changes in temperature extremes due to LUC are comparable in magnitude to changes arising from half a degree of global warming. We also demonstrate that LUC contributes to more than 20% of the change in temperature extremes for large land areas concentrated over the Northern Hemisphere. However, we also identify sources of uncertainty that influence the multimodel consensus of our results including how LUC is implemented and the corresponding biogeophysical feedbacks that perturb climate. Therefore, our results highlight the urgent need to resolve the challenges in implementing LUC across models to quantify the impacts and consider how LUC contributes to regional changes in extremes associated with sustainable development pathways.
Climate Impact of a Regional Nuclear Weapons Exchange: An Improved Assessment Based On Detailed Source Calculations
Authors: Reisner Jon , D'Angelo Gennaro , Koo Eunmo , Even Wesley , Hecht Matthew , Hunke Elizabeth , Comeau Darin , Bos Randall , Cooley James
Published: February 2018

We present a multiscale study examining the impact of a regional exchange of nuclear weapons on global climate. Our models investigate multiple phases of the effects of nuclear weapons usage, including growth and rise of the nuclear fireball, ignition and spread of the induced firestorm, and comprehensive Earth system modeling of the oceans, land, ice, and atmosphere. This study follows from the scenario originally envisioned by Robock, Oman, Stenchikov, et al. (2007, https://doi.org/10.5194/acp-7-2003-2007), based on the analysis of Toon et al. (2007, https://doi.org/10.5194/acp-7-1973-2007), which assumes a regional exchange between India and Pakistan of fifty 15 kt weapons detonated by each side. We expand this scenario by modeling the processes that lead to production of black carbon, in order to refine the black carbon forcing estimates of these previous studies. When the Earth system model is initiated with 5 × 109 kg of black carbon in the upper troposphere (approximately from 9 to 13 km), the impact on climate variables such as global temperature and precipitation in our simulations is similar to that predicted by previously published work. However, while our thorough simulations of the firestorm produce about 3.7 × 109 kg of black carbon, we find that the vast majority of the black carbon never reaches an altitude above weather systems (approximately 12 km). Therefore, our Earth system model simulations conducted with model‐informed atmospheric distributions of black carbon produce significantly lower global climatic impacts than assessed in prior studies, as the carbon at lower altitudes is more quickly removed from the atmosphere. In addition, our model ensembles indicate that statistically significant effects on global surface temperatures are limited to the first 5 years and are much smaller in magnitude than those shown in earlier works. None of the simulations produced a nuclear winter effect. We find that the effects on global surface temperatures are not uniform and are concentrated primarily around the highest arctic latitudes, dramatically reducing the global impact on human health and agriculture compared with that reported by earlier studies. Our analysis demonstrates that the probability of significant global cooling from a limited exchange scenario as envisioned in previous studies is highly unlikely, a conclusion supported by examination of natural analogs, such as large forest fires and volcanic eruptions.
Modeling the TTL at Continental Scale for a Wet Season: An Evaluation of the BRAMS Mesoscale Model Using TRO‐Pico Campaign, and Measurements From Airborne and Spaceborne Sensors
Authors: Behera Abhinna K. , Rivière Emmanuel D. , Marécal Virginie , Rysman Jean‐François , Chantal Claud , Sèze Geneviève , Amarouche Nadir , Ghysels Mélanie , Khaykin Sergey M. , Pommereau Jean‐Pierre , Held Gerhard , Burgalat Jérémie , Durry Georges
Published: February 2018

In order to better understand the water vapor (WV) intrusion into the tropical stratosphere, a mesoscale simulation of the tropical tropopause layer using the BRAMS (Brazilian version of Regional Atmospheric Modeling System (RAMS)) model is evaluated for a wet season. This simulation with a horizontal grid point resolution of 20 km × 20 km cannot resolve the stratospheric overshooting convection (SOC). Its ability to reproduce other key parameters playing a role in the stratospheric WV abundance is investigated using the balloon‐borne TRO‐Pico campaign measurements, the upper‐air soundings over Brazil, and the satellite observations by Aura Microwave Limb Sounder, Microwave Humidity Sounder, and Geostationary Operational Environmental Satellite 12. The BRAMS exhibits a good ability in simulating temperature, cold‐point, WV variability around the tropopause. However, the simulation is typically observed to be warmer by ∼2.0°C and wetter by ∼0.4 ppmv at the hygropause, which can be partly affiliated with the grid boundary nudging of the model by European Centre for Medium‐Range Weather Forecasts operational analyses. The modeled cloud tops show a good correlation (maximum cross‐correlation of ∼0.7) with Geostationary Operational Environmental Satellite 12. Furthermore, the overshooting cells detected by Microwave Humidity Sounder are observed at the locations, where 75% of the modeled cloud tops are higher than 11 km. Finally, the modeled inertia‐gravity wave periodicity and wavelength are comparable with those deduced from the radio sounding measurements during TRO‐Pico campaign. The good behavior of BRAMS confirms the SOC contribution in the WV abundance, and variability is of lesser importance than the large‐scale processes. This simulation can be used as a reference run for upscaling the impact of SOC at a continental scale for future studies.
The Thickness and Volume of Young Basalts Within Mare Imbrium
Authors: Chen Yuan , Li Chunlai , Ren Xin , Liu Jianjun , Wu Yunzhao , Lu Yu , Cai Wei , Zhang Xunyu
Published: February 2018

Basaltic volcanism is one of the most important geologic processes of the Moon. Research on the thickness and volume of late‐stage basalts of Mare Imbrium helps better understand the source of lunar volcanism and eruption styles. Based on whether apparent flow fronts exist or not, the late‐stage basalts within Mare Imbrium were divided into two groups, namely, Upper Eratosthenian basalts (UEm) and Lower Eratosthenian basalts (LEm). Employing the topographic profile analysis method for UEm and the crater excavation technique for LEm, we studied the thickness and distribution of Eratosthenian basalts in Mare Imbrium. For the UEm units, their thicknesses were estimated to be ~16–34 (±2) m with several layers of individual lava (~8–13 m) inside. The estimated thickness of LEm units was ~14–45(±1) m, with a trend of reducing thickness from north to south. The measured thickness of late‐stage basalts around the Chang'E‐3 landing site (~37 ± 1 m) was quite close to the results acquired by the lunar penetrating radar carried on board the Yutu Rover (~35 m). The total volume of the late‐stage basalts in Mare Imbrium was calculated to be ~8,671 (±320) km3, which is 4 times lower than that of Schaber's estimation (~4 × 104 km3). Our results indicate that the actual volume is much lower than previous estimates of the final stage of the late basaltic eruption of Mare Imbrium. Together, the area flux and transport distance of the lava flows gradually decreased with time. These results suggest that late‐stage volcanic evolution of the Moon might be revised.
Promotion Effect of Asian Dust on Phytoplankton Growth and Potential Dissolved Organic Phosphorus Utilization in the South China Sea
Authors: Chu Qiang , Liu Ying , Shi Jie , Zhang Chao , Gong Xiang , Yao Xiaohong , Guo Xinyu , Gao Huiwang
Published: February 2018

Dust deposition is an important nutrient source to the South China Sea (SCS), but few in situ experiments were conducted on phytoplankton response to the deposition. We conducted onboard incubation experiments at three stations near Luzon Strait in the SCS, with addition of multiple dissolved inorganic nutrients, Asian dust, and rainwater. From our results, nitrogen and phosphorus were both urgently needed for phytoplankton growth in the SCS, indicated by the evident Chl a response to the addition of nitrogen and phosphorus together. Almost no evident response was observed by adding phosphorus or iron alone to incubation waters, although a delayed response of Chl a in mass concentration was observed by adding nitrogen alone. The latter implied a possible utilization of dissolved organic phosphorus because of insufficient dissolved inorganic phosphorus in incubation waters. Under such nutrient condition, Asian dust showed an apparent promotion effect on phytoplankton growth by providing sufficient amounts of nitrogen but low phosphorus. Meanwhile, it was found that large sized (> 5 μm) phytoplankton community showed different responses to dust addition at different stations. At stations A3 and A6, Chaetoceros spp. became the dominant species during the bloom period, while at station WG2, Nitzschia spp. became dominant. In combination with different initial nutrients and Chl a levels at the three stations, the different phytoplankton community evolution implied the response difference to external inputs between oligotrophic (stations A3 and A6) and ultraoligotrophic (station WG2) conditions in the SCS.
Calculation of Voltages in Electric Power Transmission Lines During Historic Geomagnetic Storms: An Investigation Using Realistic Earth Impedances
Authors: Lucas Greg M. , Love Jeffrey J. , Kelbert Anna
Published: February 2018

Commonly, one‐dimensional (1‐D) Earth impedances have been used to calculate the voltages induced across electric power transmission lines during geomagnetic storms under the assumption that much of the three‐dimensional structure of the Earth gets smoothed when integrating along power transmission lines. We calculate the voltage across power transmission lines in the mid‐Atlantic region with both regional 1‐D impedances and 64 empirical 3‐D impedances obtained from a magnetotelluric survey. The use of 3‐D impedances produces substantially more spatial variance in the calculated voltages, with the voltages being more than an order of magnitude different, both higher and lower, than the voltages calculated utilizing regional 1‐D impedances. During the March 1989 geomagnetic storm 62 transmission lines exceed 100 V when utilizing empirical 3‐D impedances, whereas 16 transmission lines exceed 100 V when utilizing regional 1‐D impedances. This demonstrates the importance of using realistic impedances to understand and quantify the impact that a geomagnetic storm has on power grids.
Understanding the Factors That Influence Risk Tolerance Among Minority Women: A Qualitative Study
Authors: Hsiao Betty , Bhalla Sonal , Mattocks Kristin , Fraenkel Liana
Published: February 2018

Objective

To explore the factors that influence risk tolerance among women from different racial/ethnic groups.

Methods

In‐depth individual interviews of non‐Hispanic African American, non‐Hispanic white, and Hispanic women ages 20–45 years were conducted by a trained interviewer using a semi‐structured interview guide to elicit the factors that influence risk tolerance among minority women. The interviews were audiotaped and professionally transcribed, with a final sample size of 36 determined by thematic saturation. The members of the research team used open coding to review and develop a list of codes, which was modified as new codes emerged. A final list of 35 codes was applied to the transcripts and combined into broader themes.

Results

The study included 30.6% non‐Hispanic African American, 33.3% non‐Hispanic white, and 36.1% Hispanic women, with a mean ± SD age of 34.8 ± 6.8 years. Several major themes explaining risk aversion among minority women emerged: discrepancies in quality of health care, perceived prejudice, lack of knowledge and education, medication beliefs, risk perception, and constrained resources. The latter was discussed most frequently.

Conclusion

While our findings identify several concerns that may be addressed through implementation of more effective communication strategies by medical providers, they also highlight that disparities are strongly influenced by the complex ways financial and social constraints impact health care decisions of minority women.
Graphene–Graphene Interactions: Friction, Superlubricity, and Exfoliation
Authors: Sinclair Robert C. , Suter James L. , Coveney Peter V.
Published: February 2018

Graphite's lubricating properties due to the “weak” interactions between individual layers have long been known. However, these interactions are not weak enough to allow graphite to readily exfoliate into graphene on a large scale. Separating graphite layers down to a single sheet is an intense area of research as scientists attempt to utilize graphene's superlative properties. The exfoliation and processing of layered materials is governed by the friction between layers. Friction on the macroscale can be intuitively understood, but there is little understanding of the mechanisms involved in nanolayered materials. Using molecular dynamics and a new forcefield, graphene's unusual behavior in a superlubric state is examined, and the energy dissipated between two such surfaces sliding past each other is shown. The dependence of friction on temperature and surface roughness is described, and agreement with experiment is reported. The accuracy of the simulated behavior enables the processes that drive exfoliation of graphite into individual graphene sheets to be described. Taking into account the friction between layers, a peeling mechanism of exfoliation is predicted to be of lower energy cost than shearing.
Hyperbolic Dispersion Dominant Regime Identified through Spontaneous Emission Variations near Metamaterial Interfaces
Authors: Lee Kwang Jin , Lee Yeon Ui , Kim Sang Jun , André Pascal
Published: February 2018

Surface plasmon polariton (SPP), hyperbolic dispersion of energy and momentum, and emission interference provide opportunities to control photoluminescence properties. However, the interplays between these regimes need to be understood to take advantage of them in optoelectronic applications. Herein, broadband variations induced by hyperbolic metamaterial (HMM) multilayer nanostructures on the spontaneous emission of selected organic chromophores are investigated. Experimental and calculated spontaneous emission lifetimes are shown to vary nonmonotonously near HMM interfaces. With the HMM number of pairs used as the analysis parameter, the lifetime is shown to be independent of the number of pairs in the surface plasmon polaritons, and emission interference dominant regimes, while it decreases in the hyperbolic dispersion dominant regime. It is also shown that the spontaneous emission lifetime is similarly affected by transverse positive and transverse negative HMMs. This work has broad implications on the rational design of functional photonic surfaces to control the luminescence of semiconductor chromophores.
Diabetic neuropathy differs between type 1 and type 2 diabetes: Insights from magnetic resonance neurography
Authors: Jende Johann M. E. , Groener Jan B. , Oikonomou Dimitrios , Heiland Sabine , Kopf Stefan , Pham Mirko , Nawroth Peter , Bendszus Martin , Kurz Felix T.
Published: February 2018

Objective

To visualize and quantify differences of microstructural nerve damage in distal symmetric diabetic neuropathy (DPN) between type 1 diabetes (T1D) and type 2 diabetes (T2D), and to detect correlations between neuropathic symptoms and serological risk factors.

Methods

Three‐tesla magnetic resonance neurography of the sciatic nerve was performed in 120 patients (T1D, n = 35; T2D, n = 85) with either DPN (n = 84) or no DPN (n = 36). Results were subsequently correlated with clinical, serological, and electrophysiological patient data.

Results

T2‐weighted (T2w)‐hyperintense lesions correlated negatively with tibial compound motor action potential (r = −0.58, p < 0.0001) and peroneal nerve conduction (r = 0.51, p = 0.0002), and positively with neuropathy disability score (NDS; r = −0.54, p < 0.0001), neuropathy symptom score (NSS; r = 0.52, p < 0.0001), and HbA1c level (r = 0.23, p = 0.014). T2w‐hypointense lesions correlated positively with NDS (r = 0.28, p = 0.002), NSS (r = 0.36, p < 0.0001), and serum triglycerides (r = 0.34, p = 0.0003), and negatively with serum high‐density lipoprotein (HDL; r = −0.48, p < 0.0001). For DPN in T1D, elevated values of T2w‐hyperintense lesions (19.67 ± 4.13% vs 12.49 ± 1.23%, p = 0.027) and HbA1c (8.74 ± 0.29% vs 7.11 ± 0.16%, p < 0.0001) were found when compared to T2D. For DPN in T2D, elevated T2w‐hypointense lesions (23.41 ± 2.69mm3 vs 11.43 ± 1.74mm3, p = 0.046) and triglycerides (220.70 ± 23.70mg/dl vs 106.60 ± 14.51mg/dl, p < 0.0001), and lower serum HDL (51.29 ± 3.02mg/dl vs 70.79 ± 4.65mg/dl, p < 0.0001) were found when compared to T1D.

Interpretation

The predominant type of nerve lesion in DPN differs between T1D and T2D. Correlations found between lesion type and serological parameters indicate that predominant nerve lesions in T1D are associated with poor glycemic control and loss of nerve conduction, whereas predominant lesions in T2D are associated with changes in lipid metabolism. These findings may be helpful for future studies on the underlying pathophysiological pathways and possible treatments for DPN in T1D and T2D. Ann Neurol 2018;83:588–598
Hybrid Indicators for Fast and Sensitive Voltage Imaging
Authors: Xu Yongxian , Peng Luxin , Wang Sicong , Wang Anqi , Ma Ruirui , Zhou Ying , Yang Jiahe , Sun De‐en , Lin Wei , Chen Xing , Zou Peng
Published: February 2018

Membrane voltage is an important biophysical signal that underlies intercellular electrical communications. A fluorescent voltage indicator is presented that enables the investigation of electrical signaling at high spatial resolution. The method is built upon the site‐specific modification of microbial rhodopsin proteins with organic fluorophores, resulting in a hybrid indicator scaffold that is one of the most sensitive and fastest orange‐colored voltage indicators developed to date. We applied this technique to optically map electrical connectivity in cultured cells, which revealed gap junction‐mediated long‐range coupling that spanned over hundreds of micrometers.
Catalyst‐Enabled Site‐Divergent Stereoselective Michael Reactions: Overriding Intrinsic Reactivity of Enynyl Carbonyl Acceptors
Authors: Uraguchi Daisuke , Shibazaki Ryo , Tanaka Naoya , Yamada Kohei , Yoshioka Ken , Ooi Takashi
Published: February 2018

A site‐divergent stereoselective Michael reaction system is developed based on the identification of two distinct catalysts. Cinchonidine‐derived thiourea catalyzes the 1,4‐addition of prochiral azlactone enolates to enynyl N‐acyl pyrazoles in a highly diastereo‐ and enantioselective manner to give stereochemically defined alkynes, while P‐spiro chiral triaminoiminophosphorane catalytically controls the stereoselective 1,6‐addition and the consecutive γ‐protonation of the vinylogous enolate intermediate to afford Z,E‐configured conjugated dienes. This 1,6‐adduct serves as a valuable precursor for the synthesis of a 2‐amino‐2‐deoxy sugar.
Electrolyte Additives for Lithium Metal Anodes and Rechargeable Lithium Metal Batteries: Progress and Perspectives
Authors: Zhang Heng , Eshetu Gebrekidan Gebresilassie , Judez Xabier , Li Chunmei , Rodriguez‐Martínez Lide M. , Armand Michel
Published: February 2018

Lithium metal (Li0) rechargeable batteries (LMBs), such as systems with a Li0 anode and intercalation and/or conversion type cathode, lithium‐sulfur (Li‐S), and lithium‐oxygen (O2)/air (Li‐O2/air) batteries, are becoming increasingly important for electrifying the modern transportation system, with the aim of sustainable mobility. Although some rechargeable LMBs (e.g. Li0/LiFePO4 batteries from Bolloré Bluecar, Li‐S batteries from OXIS Energy and Sion Power) are already commercially viable in niche applications, their large‐scale deployment is hampered by a number of formidable challenges, including growth of lithium dendrites, electrolyte instability towards high voltage intercalation‐type cathodes, the poor electronic and ionic conductivities of sulfur (S8) and O2, as well as their corresponding reduction products (e.g. Li2S and Li2O), dissolution, and shuttling of polysulfide (PS) intermediates. This leads to a short lifecycle, low coulombic/energy efficiency, poor safety, and a high self‐discharge rate. The use of electrolyte additives is considered one of the most economical and effective approaches for circumventing these problems. This Review gives an overview of the various functional additives that are being applied and aims to stimulate new avenues for the practical realization of these appealing devices.
Dynamic Kinetic Resolution of Heterobiaryl Ketones by Zinc‐Catalyzed Asymmetric Hydrosilylation
Authors: Hornillos Valentín , Carmona José A. , Ros Abel , Iglesias‐Sigüenza Javier , López‐Serrano Joaquín , Fernández Rosario , Lassaletta José M.
Published: February 2018

A diastereo‐ and highly enantioselective dynamic kinetic resolution (DKR) of configurationally labile heterobiaryl ketones is described. The DKR proceeds by zinc‐catalyzed hydrosilylation of the carbonyl group, thus leading to secondary alcohols bearing axial and central chirality. The strategy relies on the labilization of the stereogenic axis that takes place thanks to a Lewis acid–base interaction between a nitrogen atom in the heterocycle and the ketone carbonyl group. The synthetic utility of the methodology is demonstrated through stereospecific transformations into either N,N‐ligands or appealing axially chiral, bifunctional thiourea organocatalysts.
Direct Cyclization of Tertiary Aryl Amines with Iodonium Ylides
Authors: Zhao Zhiguo , Luo Yongrui , Liu Shuya , Zhang Liang , Feng Lei , Wang Yao
Published: February 2018

Described herein is a direct cyclization of simple tertiary aryl amines with iodonium ylides leading to a broad range of N‐heterocycles. Completely different from the known reactivity of iodonium ylides, the finding reported herein is that an iodonium ylide is capable of cleaving a C(sp3)−H bond and accepting two hydrogen atoms of a tertiary aryl amine, thus inducing a novel cyclization process. This transformation can proceed without the assistance of a transition‐metal catalyst and eliminates the need for the premodification of the amine or the use of an additional initiator/oxidant.
Metal complexes of novel Schiff base derived from iron sandwiched organometallic and 4‐nitro‐1,2‐phenylenediamine: Synthesis, characterization, DFT studies, antimicrobial activities and molecular docking
Authors: Mahmoud Walaa H. , Deghadi Reem G. , Mohamed Gehad G.
Published: February 2018

The condensation of 2‐acetylferrocene with 4‐nitro‐1,2‐phenylenediamine in a 1:1 molar ratio, resulting in formation of a novel bi‐dentate organometallic Schiff base ligand (L), (2‐(1‐((2‐amino‐5‐nitrophenyl)imino)ethyl)cyclopenta‐2,4‐dien‐1‐yl)(cyclopenta‐2,4‐dien‐1‐yl)iron. Also, its Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes have been synthesized. The stoichiometric ratios of the prepared compounds were estimated using elemental analysis (C, H, N, M), molar conductivity, FT‐IR, UV‐Vis, 1H‐NMR, SEM and mass spectral analysis. Furthermore, their TG and DTG properties were studied. The geometrical structure of the complexes was found to be octahedral. From spectral analysis, the Schiff base coordinated to metal ions through the azomethine and amine groups. DFT‐based molecular orbital energy calculations of the synthesized ligand have been studied, in which the ligand was theoretically optimized. The Schiff base and its metal complexes have been screened for their antimicrobial activities against different bacterial and fungal species by using disc diffusion method. The anticancer activities of the ligand and its metal complexes have also been studied towards breast cancer (MCF‐7) and human normal melanocytes (HFB‐4) cell lines. Molecular docking was also used to identify the interaction between the Schiff base ligand and its Cd(II) complex with the active site of the receptors of breast cancer mutant oxidoreductase (PDB ID: 3HB5), crystal structure of Staphylococcus aureus (PDB ID: 3Q8U) and yeast‐specific serine/threonine protein phosphatase (PPZ1) of Candida albicans (PDB ID:5JPE).
Pyrene‐functional star polymers as fluorescent probes for nitrophenolic compounds
Authors: Tasci Enis , Aydin Muhammet , Gorur Mesut , Gürek Ayşe Gül , Yilmaz Faruk
Published: February 2018

Novel tetra‐armed star‐shaped styrenic copolymers with pyrene side groups [(S1‐S3)‐Pyr] were prepared and employed as fluorescence sensing probe for fast and sensitive determination of nitroaromatic compounds. (S1‐S3)‐Pyr depicted characteristic pyrene monomer emission signals as well as broad excimer bands in their fluorescence emission spectra due to close proximity of the pyrene groups on the polymer chains and the ratio of monomer to excimer emission intensities gradually decreased as the pyrene content of the star polymers were increased from S1‐Pyr to S3‐Pyr. The highest quenching efficiency in the presence of 25 equivalent nitroaromatics was observed for 2,4,6‐trinitrophenol/picric acid (99.4%) followed by 2,4‐dinitrophenol (84.2%), 4‐nitrophenol (82.6%), 2,4,6‐trinitrotoluene (44.0%), 2,4‐dinitrotolunene (32.6%), and 4‐nitrotoluene (28.8%). Superior quenching efficiencies of nitrophenolic compounds were ascribed to their strong binding affinity for (S1‐S3)‐Pyr due to the acidity of phenolic hydroxyl units. Besides, quenching ratios of S1‐Pyr, S2‐Pyr, and S3‐Pyr were measured to be very close to each other. Thus, (S1‐S3)‐Pyr are considered to be highly selective and sensitive fluorescence probes for phenolic nitroaromatic compounds. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46310.
Determination of the Selection Capacity of Antibiotics for Gene Selection
Authors: Delrue Iris , Pan Qiubao , Baczmanska Anna K. , Callens Bram W. , Verdoodt Lia L. M.
Published: February 2018

Choosing a potent selection antibiotic (SA), is a crucial success factor when creating stably transfected cell lines using an antibiotic selection marker. The selection capacity of this antibiotic is defined as its ability to kill sensitive, untransfected parental cells, while leaving resistant, transfected cells unharmed. Currently, no procedure has been described to determine this selection capacity. Therefore, a protocol to obtain a numerical value, called the “selectivity factor” (SF), that defines the selection capacity of SAs is developed. The SF is determined by using a modified MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐diphenyltetrazolium bromide) assay for both sensitive and resistant cells, and applies to commonly used cell lines. To prove the concept, the SF of the SA G418 and hygromycin B (HmB) on several cell lines is determined. The SF of G418 on BHK‐21 cells is very high, indicating that G418 is an ideal SA for transfected BHK‐21 cells. For HeLa cells, the SF of G418 is very low suggesting G418 is not an optimal SA for selecting transfected HeLa cells. For these cells, HmB would be a better choice. These conclusions are confirmed by an independent cell death assay. The SF identifies the most optimal SA for a certain cell line, reduces the risk of selecting spontaneously resistant cell clones, and streamlines the process of generating stable cell lines. Most importantly, the method is especially time saving when obtaining stable cell lines expressing toxic genes, and reduces culture times for generating large numbers of cell lines from the same parental cell line.
Selective Synthesis of N,N‐Bis(3‐dimethylaminopropyl)amine over Pd/γ‐Al2O3
Authors: Lin Chenhui , Wang Bowei , Guo Haotian , Chen Ligong , Yan Xilong
Published: February 2018

The synthesis of N,N‐bis(3‐dimethylaminopropyl)amine (BPA) from 3‐(dimethylamino)‐propionitrile (PN) and 3‐(N,N‐dimethylamino)propylamine (PA) over Pd/γ‐Al2O3 in autoclaves was investigated. A series of Pd catalysts were prepared by different methods and characterized by XRD, TEM, and N2 adsorption–desorption. It was found that their activities were obviously affected by calcination temperature and reducing agent. Among them, the catalyst calcined at 500 °C and reduced with NaBH4 exhibited the best performance in this reaction. It was possibly attributed to the better dispersion of palladium particles on γ‐Al2O3. Furthermore, reaction parameters were also optimized. Under optimal conditions (PN/PA molar radio 1:1, toluene as solvent), BPA was obtained in 87.9% yield with 95.6% conversion over the above catalyst. Meanwhile, split of PN was observed. A probable mechanism of retro‐Michael reaction was also proposed.
Knowledge about cervical cancer and barriers toward cervical cancer screening among HIV‐positive women attending public health centers in Addis Ababa city, Ethiopia
Authors: Shiferaw Saba , Addissie Adamu , Gizaw Muluken , Hirpa Selamawit , Ayele Wondimu , Getachew Sefonias , Kantelhardt Eva J. , Assefa Mathewos , Jemal Ahmedin
Published: February 2018

Screening rate for cervical cancer among HIV‐infected women and among women overall is low in Ethiopia despite the high burden of the disease and HIV infection, which increases cervical cancer risk. In this paper, we assessed knowledge about cervical cancer symptoms, prevention, early detection, and treatment and barriers to screening among HIV‐positive women attending community health centers for HIV‐infection management in Addis Ababa. A cross‐sectional survey of 581 HIV‐positive women aged 21–64 years old attending 14 randomly selected community health centers without cervical cancer screening service in Addis Ababa. We used univariate analysis to calculate summary statistics for each variable considered in the analysis, binary logistic regression analysis to measure the degree of association between dependent and independent variables, and multiple regressions for covariate adjusted associations. Statistical significance for all tests was set at P < 0.05. We used thematic analysis to describe the qualitative data. Of the 581 women enrolled in the study with mean age 34.9 ± 7.7 years, 57.8% of participants had heard of cervical cancer and 23.4% were knowledgeable about the symptoms, prevention, early detection, and treatment of the disease. In multivariate analysis, higher educational attainment and employment were significantly associated with good knowledge about cervical cancer. In addition, only 10.8% of the participants ever had screening and 17% ever received recommendation for it. However, 86.2% of them were willing to be screened if free of cost. Knowledge about cervical cancer is poor and cervical cancer screening rate and provider recommendation are low among HIV‐positive women attending community health centers for management and follow‐up of their disease in Addis Ababa. These findings underscore the need to scale up health education about cervical cancer prevention and early detection among HIV‐positive women as well as among primary healthcare providers in the city.
Novel N‐Mo2C Active Sites for Efficient Solar‐to‐Hydrogen Generation
Authors: Abbas Syed Comail , Peng Zeng , Wu Jing , Anandhababu Ganesan , Babu Dickson D. , Huang Yiyin , Ghausi Muhammad Arsalan , Wu Maoxiang , Wang Yaobing
Published: February 2018

Hydrogen production from water driven by electrochemical/solar energy is extremely desirable, but it requires a capable and robust electrocatalyst for the hydrogen evolution reaction (HER). For the aforesaid purpose, molybdenum carbide (Mo2C) has been considered as an efficient electrocatalyst for hydrogen production; however, N‐Mo2C has been less focused upon. For this purpose, we report a facile method for the synthesis of N‐Mo2C active species. The as‐synthesized electrocatalyst exhibits a remarkable electrochemical performance for HER with a small onset potential of 30.6 mV vs. RHE and requires overpotential (η) of only 99.3 mV vs. RHE to render −10 mA cm−2 current density. The Tafel slope of 62.8 mV dec−1 further demonstrates the favorable reaction kinetics of the electrocatalyst. Moreover, for practical applications, solar‐driven hydrogen production has been efficiently implemented, which shows excellent faradaic efficiency (95.2 %) as well as solar‐to‐hydrogen generation efficiency (1.14 %). This facile approach for the synthesis of N‐Mo2C active species can provide valuable enlightenment for the further development of photo‐/electrocatalysts.
Carbon Nanorod−MoS2 Core−Sheath Heterostructure and Its Electrochemical Properties over Various Electrochemical Windows
Authors: Wu Manman , Liu Cong , Xu Hui , Shen Jiandong , Yang Yang , Yang Gang
Published: February 2018

The powder of a carbon nanorod−MoS2 core−sheath heterostructure is successfully synthesized by using a hydrothermal method. The carbon nanorod−MoS2 material is composed of hierarchical MoS2 nanosheets tightly grown on carbon nanorods, in which the carbon nanorods as a template effectively reduce the aggregation of the MoS2 nanosheets. The electrochemical properties of the carbon nanorod−MoS2 composite electrode are studied in detail, as the intercalation of lithium into MoS2 includes two significant changes in lithiation mechanism, which occur over various electrochemical windows, such as from 1.0 to 3.0 V and from 0.001 to 3.0 V. The former mainly corresponds to the intercalation/extraction of lithium cations, and thus it presents excellent cyclic stability but low specific capacity. The later causes a big phase change in the final Li‐Sulfur battery system, and thus delivers a high specific capacity but is accompanied by serious pulverization and consequential fast capacity fading. MoS2 supported by carbon nanorods presents a better electrochemical performance than the pure MoS2 sample over various electrochemical windows.
Bioorthogonal Metabolic DNA Labelling using Vinyl Thioether‐Modified Thymidine and o‐Quinolinone Quinone Methide
Authors: Gubu Amu , Li Long , Ning Yan , Zhang Xiaoyun , Lee Seonghyun , Feng Mengke , Li Qiang , Lei Xiaoguang , Jo Kyubong , Tang Xinjing
Published: February 2018

Bioorthogonal metabolic DNA labeling with fluorochromes is a powerful strategy to visualize DNA molecules and their functions. Here, we report the development of a new DNA metabolic labeling strategy enabled by the catalyst‐free bioorthogonal ligation using vinyl thioether modified thymidine and o‐quinolinone quinone methide. With the newly designed vinyl thioether‐modified thymidine (VTdT), we added labeling tags on cellular DNA, which could further be linked to fluorochromes in cells. Therefore, we successfully visualized the DNA localization within cells as well as single DNA molecules without other staining reagents. In addition, we further characterized this bioorthogonal DNA metabolic labeling using DNase I digestion, MS characterization of VTdT as well as VTdT‐oQQF conjugate in cell nuclei or mitochondria. This technique provides a powerful strategy to study DNA in cells, which paves the way to achieve future spatiotemporal deciphering of DNA synthesis and functions.
Cover Picture: Recent Advances in Transition Metal‐Catalyzed Asymmetric Radical Reactions (Chin. J. Chem. 3/2018)
Authors: Wang Kuai , Kong Wangqing
Published: February 2018

The control of stereoselectivity in radical reactions is of great importance, but remains a formidable challenge. The cover picture shows that the enantiomerically pure compounds can be prepared in radical transformations using chiral transition metal complexes as catalysts. Recent advances are summarized in the review by Kong et al. on page 247–256.

image
Odanacatib Pharmacokinetics Comparison Between Chinese and Non‐Chinese Postmenopausal Women
Authors: Chen Xia , Jiang Ji , Hu Pei , Zajic Stefan , Liu Wen , McCrea Jacqueline , Liu Fang , Witter Rose , Mangin Eric , Stoch S. Aubrey
Published: February 2018

Odanacatib (ODN), an oral selective inhibitor of cathepsin K, was an investigational agent previously in development for the treatment of osteoporosis. In this phase 1 open‐label study, 12 healthy Chinese postmenopausal women received single‐dose ODN 50 mg on day 1 and multiple‐dose ODN 50 mg once weekly on days 15, 22, 29, and 36 under fasted conditions. Pharmacokinetic (PK) parameters were evaluated on days 1 and 36. Multiple‐dose area under the concentration–time profile (AUC0–168h) and maximum plasma concentration (Cmax) were compared with historical data from 9 non‐Chinese postmenopausal women who also received ODN 50 mg once weekly for 4 weeks. Median time to Cmax (tmax) was 3 and 4 hours following single‐ and multiple‐dose administration, respectively. The arithmetic mean ± SD terminal half‐life was 81.0 ± 14.0 and 106.7 ± 14.4 hours following single‐ and multiple‐dose administration, respectively. Comparison of multiple‐dose PK parameters showed that the geometric mean ratios (Chinese/non‐Chinese) and 95%CIs for AUC0–168h and Cmax were 0.81 (0.55‒1.19) and 0.87 (0.69‒1.11), respectively. All adverse events were mild, none were serious, and none led to discontinuation. Single‐ and multiple‐dose PKs of ODN 50 mg in Chinese postmenopausal women were generally similar to those previously reported in non‐Chinese postmenopausal women.
Retaining volunteer mediators: Comparing predictors of burnout
Authors: Harmon‐Darrow Caroline , Xu Yanfeng
Published: February 2018

Retention of the estimated 30,000 U.S. volunteer community mediators is critical to provision of high‐quality services. Although workers’ retention and burnout is well researched, retention of volunteers such as community mediators is less understood. Survey data of 53 volunteer mediators were analyzed. For volunteer mediators, burnout and intent to remain for 2 years were significantly negatively associated. Using a self‐determination‐based basic needs satisfaction scale, more relatedness satisfaction predicted lower burnout for volunteer mediators, while competence satisfaction and autonomy satisfaction did not. This association held, even when controlling for mediators’ experience in the field and self‐care behaviors.
The role of plasma analytics in leading‐edge semiconductor technologies
Authors: Zimmermann S. , Haase M. , Lang N. , Röpcke J. , Schulz S.E. , Otto T.
Published: February 2018

Plasma patterning processes play a key role in modern Ultra Large Scale Integration (ULSI) device fabrication. With further scaling of device dimensions, plasma process characteristics become more and more the limiting factor in pattern minimization, not least due to parasitic effects caused by different plasma properties. Such effects are geometrical deviations in the etch profiles, the loss of critical dimensions, the undercut as well as the most critical sidewall damage while etching trenches and vias to fabricate the circuit contact and metallization system. Especially for modern dielectric materials on the base of carbon‐doped silica these drawbacks are much pronounced and worsen performance and power consumption of microelectronic devices. Finally, the charge damage of thin gate oxides during plasma processing results in reduced reliability and functionality of microelectronic devices. The complex interactions between conditions in the plasma bulk and the impacts on the wafer surface are not yet understood completely. With respect to the increasing complexity of modern semiconductor plasma etch equipment, the optimization of patterning processes using the empirical method becomes more and more impossible. This paper overviews typical challenges during plasma patterning processes in 28 nm and 22 nm technology nodes by means of today's Back‐End of Line integration schemes. Different plasma diagnostic methods provide an insight into the physical and chemical conditions of different etch chambers and their influence on process results and damaging behaviour.
Application of the partial safety concept for complex non‐linear calculations through the example of Friedrichswerder Church in Berlin
Authors: Bakeer Tammam
Published: February 2018

Non‐linear analysis of special structures is routine practice in every engineering design office. Current code provisions provide no sufficient regulations or clear procedures on how to use partial safety factors in non‐linear analyses. The present paper introduces some specific problems of masonry structures from practice.

Limit state functions of vertically loaded masonry walls were investigated. A reliability study shows that the decisive case of verification can be obtained by considering a special combination of material parameters. The study also indicates the importance of considering a partial factor for the elastic modulus to account for stability failure.

This proposed procedure has been applied to a practical example, the Friedrichswerder Church. The stability of the church has been checked with many FEM models at the macro level.
Advanced imaging technology applications in cytology
Authors: Pantanowitz Liron , Preffer Frederic , Wilbur David C.
Published: February 2018

Novel techniques have been developed to image cells at cellular and subcellular levels. They allow images to be analyzed with ultra‐high resolution, in 2D and/or 3D. Several of these tools have been tested on cytology specimens demonstrating emerging applications that are likely to change the field of cytopathology. This review covers several of these advanced imaging methods. The use of optical coherence tomography to perform optical biopsies during endoscopic ultrasound procedures or visualize cells within effusion samples is discussed. The potential for quantitative phase microscopy to accurately screen Pap test slides or resolve indeterminate diagnoses in urine cytology is reviewed. The article also examines the application of 3D cytology using LuCED for lung cancer detection in sputum samples and the feasibility of imaging flow and mass cytometry to measure multiple biomarkers at the single cell level. Although these novel technologies have great potential, further research is necessary to validate their routine use in cytopathology practice.