bluuebunny/crossref_metadata_2025 huggingface dataset:
Coherent intraseasonal oceanic variations in the eastern equatorial Indian Ocean and in the Lombok and Ombai Straits from observations and a high‐resolution OGCM
Authors: Iskandar Iskhaq , Masumoto Yukio , Mizuno Keisuke , Sasaki Hideharu , Affandi Azhar K. , Setiabudidaya Dedi , Syamsuddin Fadli
Published: February 2014

Ongoing acoustic Doppler current profilers (ADCP) observation in the eastern equatorial Indian Ocean and a recent International Nusantara Stratification and Transport (INSTANT) experiment in the Indonesian Throughflow (ITF) straits have shown coherent intraseasonal oceanic variations in this region. The intraseasonal variations are dominated by 30–70 day variations, with a tendency for the observed currents in the eastern equatorial Indian Ocean to lead those at the Lombok and Ombai Straits. Phase speed of these eastward propagating signals estimated using lag correlation analysis does not correspond to one particular baroclinic mode, though it is in the range expected for the first two baroclinic modes. In this study, the dynamics underlying this intraseasonal coherency is evaluated using output from a high‐resolution ocean general circulation model developed for the Earth Simulator (OFES). The results from model simulation of January 2001 through December 2007 show that the first two baroclinic modes dominate the intraseasonal variations in this region. While the first and second baroclinic modes have comparable contribution to the intraseasonal oceanic variations in the eastern equatorial Indian Ocean and in the Ombai Strait, the intraseasonal oceanic variations in the Lombok Strait are dominated by the first baroclinic mode. Moreover, the analysis reveals that the intraseasonal variability at all mooring sites is mostly confined in the upper layer above ∼100 m depth. Both equatorial wind from the Indian Ocean and alongshore winds off Sumatra and Java play important roles in generating intraseasonal variations in the Lombok and Ombai Straits.
Postlaunch performance of the Suomi National Polar‐orbiting Partnership Ozone Mapping and Profiler Suite (OMPS) nadir sensors
Authors: Seftor C. J. , Jaross G. , Kowitt M. , Haken M. , Li J. , Flynn L. E.
Published: February 2014

The prelaunch specifications for nadir sensors of the Ozone Mapping and Profiler Suite (OMPS) were designed to ensure that measurements from them could be used to retrieve total column ozone and nadir ozone profile information both for operational use and for use in long‐term ozone data records. In this paper, we will show results from our extensive analysis of the performance of the nadir mapper (NM) and nadir profiler (NP) sensors during the first year and a half of OMPS nadir operations. In most cases, we determined that both sensors meet or exceed their prelaunch specifications. Normalized radiance (radiance divided by irradiance) measurements have been determined to be well within their 2% specification for both sensors. In the case of stray light, the NM sensor is within its 2% specification for all but the shortest wavelengths, while the NP sensor is within its 2% specification for all but the longest wavelengths. Artifacts that negatively impacted the sensor calibration due to diffuser features were reduced to less than 1% through changes made in the solar calibration sequence. Preliminary analysis of the disagreement between measurements made by the NM and NP sensors in the region where their wavelengths overlap indicates that it is due to shifts in the shared dichroic filter after launch and that it can be corrected. In general, our analysis indicates that both the NM and NP sensors are performing well, that they are stable, and that any deviations from nominal performance can be well characterized and corrected.
Evaluation of the Sensor Data Record from the nadir instruments of the Ozone Mapping Profiler Suite (OMPS)
Authors: Wu Xiangqian , Liu Quanhua , Zeng Jian , Grotenhuis Michael , Qian Haifeng , Caponi Maria , Flynn Larry , Jaross Glen , Sen Bhaswar , Buss Richard H. , Johnsen William , Janz Scott , Pan Chunhui , Niu Jianguo , Beck Trevor , Beach Eric , Yu Wei , Rama Varma Raja M. K. , Stuhmer Derek , Cumpton Daniel , Owen Cristina , Li Wen‐Hao
Published: February 2014

This paper evaluates the first 15 months of the Ozone Mapping and Profiler Suite (OMPS) Sensor Data Record (SDR) acquired by the nadir sensors and processed by the National Oceanic and Atmospheric Administration Interface Data Processing Segment. The evaluation consists of an inter‐comparison with a similar satellite instrument, an analysis using a radiative transfer model, and an assessment of product stability. This is in addition to the evaluation of sensor calibration and the Environment Data Record product that are also reported in this Special Issue. All these are parts of synergetic effort to provide comprehensive assessment at every level of the products to ensure its quality. It is found that the OMPS nadir SDR quality is satisfactory for the current Provisional maturity. Methods used in the evaluation are being further refined, developed, and expanded, in collaboration with international community through the Global Space‐based Inter‐Calibration System, to support the upcoming long‐term monitoring.
Spatial and temporal patterns of global burned area in response to anthropogenic and environmental factors: Reconstructing global fire history for the 20th and early 21st centuries
Authors: Yang Jia , Tian Hanqin , Tao Bo , Ren Wei , Kush John , Liu Yongqiang , Wang Yuhang
Published: February 2014

Fire is a critical component of the Earth system, and substantially influences land surface, climate change, and ecosystem dynamics. To accurately predict the fire regimes in the 21st century, it is essential to understand the historical fire patterns and recognize the interaction among fire, human, and environment factors. Until now, few efforts are put on the studies regarding to the long‐term fire reconstruction and the attribution analysis of anthropogenic and environmental factors to fire regimes at global scale. To fill this knowledge gap, we developed a 0.5° × 0.5° data set of global burned area from 1901 to 2007 by coupling Global Fire Emission Database version 3 with a process‐based fire model and conducted factorial simulation experiments to evaluate the impacts of human, climate, and atmospheric components. The average global burned area is ~442 × 104 km2 yr−1during 1901–2007 and our results suggest a notable declining rate of burned area globally (1.28 × 104 km2 yr−1). Burned area in tropics and extratropics exhibited a significant declining trend, with no significant trend detected at high latitudes. Factorial experiments indicated that human activities were the dominant factor in determining the declining trend of burned area in tropics and extratropics, and climate variation was the primary factor controlling the decadal variation of burned area at high latitudes. Elevated CO2and nitrogen deposition enhanced burned area in tropics and southern extratropics but suppressed fire occurrence at high latitudes. Rising temperature and frequent droughts are becoming increasingly important and expected to increase wildfire activity in many regions of the world.
CMIP5 historical simulations (1850–2012) with GISS ModelE2
Authors: Miller Ron L. , Schmidt Gavin A. , Nazarenko Larissa S. , Tausnev Nick , Bauer Susanne E. , DelGenio Anthony D. , Kelley Max , Lo Ken K. , Ruedy Reto , Shindell Drew T. , Aleinov Igor , Bauer Mike , Bleck Rainer , Canuto Vittorio , Chen Yonghua , Cheng Ye , Clune Thomas L. , Faluvegi Greg , Hansen James E. , Healy Richard J. , Kiang Nancy Y. , Koch Dorothy , Lacis Andy A. , LeGrande Allegra N. , Lerner Jean , Menon Surabi , Oinas Valdar , Pérez García‐Pando Carlos , Perlwitz Jan P. , Puma Michael J. , Rind David , Romanou Anastasia , Russell Gary L. , Sato Makiko , Sun Shan , Tsigaridis Kostas , Unger Nadine , Voulgarakis Apostolos , Yao Mao‐Sung , Zhang Jinlun
Published: February 2014

Observations of climate change during the CMIP5 extended historical period (1850–2012) are compared to trends simulated by six versions of the NASA Goddard Institute for Space Studies ModelE2 Earth System Model. The six models are constructed from three versions of the ModelE2 atmospheric general circulation model, distinguished by their treatment of atmospheric composition and the aerosol indirect effect, combined with two ocean general circulation models, HYCOM and Russell. Forcings that perturb the model climate during the historical period are described. Five‐member ensemble averages from each of the six versions of ModelE2 simulate trends of surface air temperature, atmospheric temperature, sea ice and ocean heat content that are in general agreement with observed trends, although simulated warming is slightly excessive within the past decade. Only simulations that include increasing concentrations of long‐lived greenhouse gases match the warming observed during the twentieth century. Differences in twentieth‐century warming among the six model versions can be attributed to differences in climate sensitivity, aerosol and ozone forcing, and heat uptake by the deep ocean. Coupled models with HYCOM export less heat to the deep ocean, associated with reduced surface warming in regions of deepwater formation, but greater warming elsewhere at high latitudes along with reduced sea ice. All ensembles show twentieth‐century annular trends toward reduced surface pressure at southern high latitudes and a poleward shift of the midlatitude westerlies, consistent with observations.
Inhibition of oil plume dilution in Langmuir ocean circulation
Authors: Yang Di , Chamecki Marcelo , Meneveau Charles
Published: February 2014

Oil spills from deep‐water blowouts rise through and interact with the ocean mixed layer and Langmuir turbulence, leading to considerable diversity of oil slick dilution patterns observed on the ocean surface. Certain conditions can drive oil droplet plumes to organize into distinct bands called windrows, inhibiting oil dilution. Observations of blurred or even diffused plumes are also common, but conditions under which these various dilution regimes emerge are not well understood. Here we use large eddy simulations to explain and quantify the dilution patterns and their dependence on relevant physical parameters. Two mechanisms, the downwelling and dilution due to Langmuir cells and the inhibition of dilution due to buoyancy of oil droplets, compete. This competition can be characterized by the ratio of Stokes drift to droplet rise velocity—the drift‐to‐buoyancy parameter, Db. We find that plume appearance and quantitative measures of relative dilution depend mainly on Db.
Promoter Fusions to Study Gene Expression
Authors: Ma Jun
Published: February 2014

One important tool in molecular biology takes advantage of promoter fusions where the expression of one gene is controlled by the promoter or regulatory elements of another gene. Promoter fusions engineered
in vitro
can help to determine how gene expression is regulated in cells and whole organisms. Promoter fusions generated
in vivo
, for example, by promoter trapping, can help to identify new genes and generate useful genetic resources for dissecting important biological processes. A binary effector–reporter system can be used to direct the production of a protein of interest in specific cells of an organism for functional studies. It can also be used to direct the production of interference
ribonucleic acid
molecules that can inhibit the activity of their target genes in specific cells of an organism. The GAL4–UAS version of this binary system is a valuable genetic tool for investigations of mechanisms that control development.

Key Concepts:

The first step towards expressing a gene is transcription.

Gene transcription is controlled by regulatory DNA sequences (elements) that contain binding sites for regulatory proteins.

The regulatory DNA element of one gene can exert its effect on the expression of another gene in a chimaeric (fusion) construct.

Engineered fusion constructs can be introduced to cells or whole organisms.

Reporter genes are used in fusion constructs because their encoded proteins can be monitored or assayed easily.

Reporter fusion constructs can be used to analyse the functions of the regulatory DNA elements.

An effector–reporter system can be used to study the relationship between a regulatory DNA element and the regulatory proteins that bind to it.

Promoter trapping and enhancer trapping are useful techniques to generate genome‐scale resources for genetic studies.

A binary effector–reporter system (a version of which is commonly known as the GAL4–UAS system) is a powerful genetic tool.
Two‐Hybrid Systems to Measure Protein–Protein Interactions
Authors: Finley Russell L , Mairiang Dumrong
Published: February 2014

To understand how proteins function to control cellular processes, their interactions with other proteins must be identified and characterised. The yeast two‐hybrid system is a simple and efficient assay for protein–protein interactions. In a yeast two‐hybrid assay, two proteins are expressed in a yeast nucleus with each protein fused to one‐half of a transcription activator. If the two hybrid proteins interact, the transcription activator is reconstituted and turns on easily detectable reporter genes. This assay has been used to identify tens of thousands of protein interactions, to map protein interaction domains and to characterise mutant variants of proteins. A variety of related assays have been developed, all based on the ability of two interacting hybrid proteins to activate a reporter system. These assays along with the original two‐hybrid assay are contributing to the characterisation of the protein interactions – or protein interactome – for humans and several model organisms.

Key Concepts:

The role that most proteins play in cells involves interacting with one or more proteins.

A binary interaction is a physical interaction between two proteins.

Understanding a protein's function requires charting its binary interactions.

Interactome is a term used to refer to all of the protein interactions for a particular cell or an entire organism.

Two‐hybrid assays are assays for binary protein interactions, where two test proteins are expressed in cells as hybrids fused to protein moieties that when brought into proximity via the protein interaction produces a detectable signal.

In a yeast two‐hybrid assay, the two proteins to be tested for interaction are fused to the two halves of a transcription factor in yeast, which activates reporter genes if the proteins interact.

In a protein complementation assay, the two proteins are fused to separate halves of a reporter protein like an enzyme, which will be reconstituted if the two halves are brought into close proximity via the protein–protein interaction.

False positives are interactions that are detected in the assay even though they do not occur under normal conditions
in vivo
.

Protein interaction assays can also result in missed interactions or false negatives.

Use of multiple different protein interaction assays can reduce the number of false negatives and provide cross‐validation to rule out false positives.
Expanding Applications of Deep Brain Stimulation
Authors: Tekriwal Anand , Keshavan Arjuna , Halpern Casey H , Baltuch Gordon H
Published: February 2014

Deep brain stimulation (DBS) has proved to be a highly effective therapy for multiple types of movement disorders. Because of its well‐tolerated procedure, low side effect profile and high degree of titratability, it has been increasingly explored as an adjunctive therapy for patients refractory to conventional care. This article examines the potential efficacy of DBS for neurological and psychiatric disorders currently under investigation. Pilot studies and clinical trials have been instructive in guiding clinicians and researchers as they seek to elucidate whether DBS is efficacious for indications like epilepsy, Tourette syndrome, addiction and even obesity. Continuing refinement of patient selection protocols and stimulatory parameters, as well as advances in stimulatory tools and surgical procedures, has contributed to these expanding applications of DBS.

Key Concepts:

Titratability is one of the key strengths of DBS as it allows clinicians the ability to adjust the ‘dose’ of stimulation at any point after implantation.

The refractory nature of neuropsychiatric disorders has created the need for direct, brain‐targeted treatments like DBS that can address treatment‐resistant cases.

Parkinson disease, a disorder resulting from the degeneration of dopamine‐producing cells in the substantia nigra, has been well treated by DBS for more than a decade.

Clinical trials, such as the SANTE trials, are crucial for demonstrating the efficacy of an experimental treatment like DBS.

Closed‐loop systems incorporate cortical EEG monitoring to time stimulatory pulses with pathological neural activity, prospectively increasing the efficacy of DBS for conditions like epilepsy.

The ‘psychiatric armamentarium’ describes the treatments and tools, mostly pharmaceuticals, available with clinicians in order to treat patients diagnosed with neuropsychiatric disorders.
Moving Water Droplets Over Nanoscaled (Super) hydrophobic Wettability Contrasts: Experimental Test of a Simple Model Describing Driving Forces
Authors: Neckernuss Tobias , Wiedemann Stefan , Plettl Alfred , Ziemann Paul
Published: February 2014

Applying advanced nanolithography techniques, various arrays of nanopillars on top of Si‐wafers are fabricated with all geometric parameters on the nanoscale. Additional chemical functionalization together with control over areal pillar density, height, and diameter allows the preparation of superhydrophobic surfaces exhibiting a wide range of contact angles (CA). Further improvement of this approach enables the production of step‐like wettability contrasts involving various CB–CB (Cassie‐Baxter) and CB–S (Smooth substrate)‐transitions. Such samples in combination with a high‐speed camera allow studying under optimized conditions quantitatively additional driving forces acting on a water droplet due to CA gradients. Experimentally it turns out that the maximum driving force on the droplet is well predicted by a simple model assuming circularly‐shaped base lines during the passage of a step‐like gradient of wettability. The provided study permits a comparison between maximum retention forces when tilting the substrate up to a critical angle and the presently determines maximum driving forces acting on a droplet due to a step‐like CA gradient. Both situations can be nicely described by a joint linear relation between normalized forces and CA hysteresis values with a slope close to theoretical values.
Very High Surface Capacity Observed Using Si Negative Electrodes Embedded in Copper Foam as 3D Current Collectors
Authors: Mazouzi Driss , Reyter David , Gauthier Magali , Moreau Philippe , Guyomard Dominique , Roué Lionel , Lestriez Bernard
Published: February 2014

Cu foam is evaluated as a replacement for metal foil current collectors to create 3D composite electrodes with the objective to produce Si‐based anodes with high loadings. The electrodes are prepared by casting the slurry into the porosity of the foam. With such a design, the loading and the surface capacity can reach values as high as 10 mg cm−2 and 10 mAh cm−2. Compared to the common 2D design, the 3D copper framework shows a great advantage in the cycle life (more than 400 cycles at a Si loading of 10 mg cm−2 with commercial micrometric particles) and power performance. The thinness of the composite coating on the foam walls favors a better preservation of the electronic wiring upon cycling and fast lithium ion diffusion. A higher coulombic efficiency in half cells with lithium metal as the counter electrode is achieved by using carbon nanofibers (CNF) rather than carbon black (CB). The possibility to reach, in practice, higher surface capacity could allow a significant increase in both the volumetric and gravimetric energy densities by 23% and 19%, respectively, for the Cu foam‐silicon//LiFePO4 stack compared to the graphite/LiFePO4 stack of traditional design.
Quantitative relationships between microstructure and effective transport properties based on virtual materials testing
Authors: Gaiselmann Gerd , Neumann Matthias , Schmidt Volker , Pecho Omar , Hocker Thomas , Holzer Lorenz
Published: February 2014

The microstructure influence on conductive transport processes is described in terms of volume fraction ε, tortuosity τ, and constrictivity β. Virtual microstructures with different parameter constellations are produced using methods from stochastic geometry. Effective conductivities
are obtained from solving the diffusion equation in a finite element model. In this way, a large database is generated which is used to test expressions describing different micro–macro relationships such as Archie's law, tortuosity, and constrictivity equations. It turns out that the constrictivity equation has the highest accuracy indicating that all three parameters
are necessary to capture the microstructure influence correctly. The predictive capability of the constrictivity equation is improved by introducing modifications of it and using error‐minimization, which leads to the following expression:
with intrinsic conductivity
. The equation is important for future studies in, for example, batteries, fuel cells, and for transport processes in porous materials. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1983–1999, 2014
The adaptive value of primate color vision for predator detection
Authors: Pessoa Daniel Marques Almeida , Maia Rafael , de Albuquerque Ajuz Rafael Cavalcanti , De Moraes Pedro Zurvaino Palmeira Melo Rosa , Spyrides Maria Helena Constantino , Pessoa Valdir Filgueiras
Published: February 2014

The complex evolution of primate color vision has puzzled biologists for decades. Primates are the only eutherian mammals that evolved an enhanced capacity for discriminating colors in the green–red part of the spectrum (trichromatism). However, while Old World primates present three types of cone pigments and are routinely trichromatic, most New World primates exhibit a color vision polymorphism, characterized by the occurrence of trichromatic and dichromatic females and obligatory dichromatic males. Even though this has stimulated a prolific line of inquiry, the selective forces and relative benefits influencing color vision evolution in primates are still under debate, with current explanations focusing almost exclusively at the advantages in finding food and detecting socio‐sexual signals. Here, we evaluate a previously untested possibility, the adaptive value of primate color vision for predator detection. By combining color vision modeling data on New World and Old World primates, as well as behavioral information from human subjects, we demonstrate that primates exhibiting better color discrimination (trichromats) excel those displaying poorer color visions (dichromats) at detecting carnivoran predators against the green foliage background. The distribution of color vision found in extant anthropoid primates agrees with our results, and may be explained by the advantages of trichromats and dichromats in detecting predators and insects, respectively. Am. J. Primatol. 76:721–729, 2014. © 2014 Wiley Periodicals, Inc.
Transition from π Radicals to σ Radicals: Substituent‐Tuned Cyclization of Hydrazonyl Radicals
Authors: Duan Xiao‐Yong , Zhou Neng‐Neng , Fang Ran , Yang Xiu‐Long , Yu Wei , Han Bing
Published: February 2014

Hydrazonyl radicals are known for their π‐electronic structures; however, their σ‐electronic structures have not been reported as yet. Herein, we show that readily accessible β,γ‐ and γ,δ‐unsaturated N‐trichloroacetyl and N‐trifluoroacetyl hydrazones can be conveniently converted into hydrazonyl σ radicals, which subsequently undergo 5‐exo‐trig radical cyclization at the N1 or N2 atom to form pyrazolines and azomethine imines, respectively.
Room‐Temperature Amination of Deactivated Aniline and Aryl Halide Partners with Carbonate Base Using a Pd‐PEPPSI‐IPentCl‐ o‐Picoline Catalyst
Authors: Pompeo Matthew , Farmer Jennifer L. , Froese Robert D. J. , Organ Michael G.
Published: February 2014

Current state‐of‐the‐art protocols for the coupling of unreactive amines (e.g., electron‐poor anilines) with deactivated oxidative‐addition partners (e.g., electron‐rich and/or hindered aryl chlorides) involve strong heating (usually >100 °C) and/or tert‐butoxide base, and even then not all couplings are successful. The aggressive base tert‐butoxide reacts with and in many instances destroys the typical functional groups that are necessary for the function of most organic molecules, such as carbonyl groups, esters, nitriles, amides, alcohols, and amines. The new catalyst described herein, Pd‐PEPPSI‐IPentCl‐o‐picoline, is able to aminate profoundly deactivated coupling partners when using only carbonate base at room temperature.
Structural Reevaluation of the Electrophilic Hypervalent Iodine Reagent for Trifluoromethylthiolation Supported by the Crystalline Sponge Method for X‐ray Analysis
Authors: Vinogradova Ekaterina V. , Müller Peter , Buchwald Stephen L.
Published: February 2014

Hypervalent iodine λ3‐benziodoxoles are common electrophilic transfer reagents known for their enhanced stability compared to their non‐cyclic analogues. Herein we present data showing that chlorobenziodoxole reacts with two different thiolate nucleophiles (thiocyanate and trifluoromethylthiolate), resulting in the formation of stable thioperoxy complexes rather than the expected benziodoxole derivatives. We further report a revised structure for the earlier described electrophilic trifluoromethylthiolation reagent (1), which was previously believed to contain the benziodoxole framework. Our findings, which are based on a combination of analytical techniques, including the recently introduced crystalline sponge method for X‐ray analysis, unambiguously demonstrate that 1 is a thioperoxy compound both in solution and the solid state.
On the Stability of a POCsp3OP‐Type Pincer Ligand in Nickel(II) Complexes
Authors: Hao Jingjun , Mougang‐Soumé Berline , Vabre Boris , Zargarian Davit
Published: February 2014

We describe the results of a study on the stabilities of pincer‐type nickel complexes relevant to catalytic hydroalkoxylation and hydroamination of olefins, CC and CX couplings, and fluorination of alkyl halides. Complexes [(POCsp3OP)NiX] are stable for X=OSiMe3, OMes (Mes=1,3,5‐Me3C6H2), NPh2, and CCH, whereas the O(tBu) and N(SiMe3)2 derivatives decompose readily. The phenylacetylide derivative transforms gradually into the zero‐valent species cis‐[{κP,κC,κC′‐(iPr2POCH2CHCH2)}Ni{η2,κC,κC′‐(iPr2P(O)CCPh)}]. Likewise, attempts to prepare [(POCsp3OP)NiF] gave instead the zwitterionic trinuclear species [{(η3‐allyl)Ni}2‐{μ,κP,κO‐(iPr2PO)4Ni}]. Characterization of these two complexes provides concrete examples of decomposition processes that can dismantle POCsp3OP‐type pincer ligands by facile CO bond rupture. These results serve as a cautionary tale for the inherent structural fragility of pincer systems bearing phosphinite donor moieties, and provide guidelines on how to design more robust analogues.
Mesoporous Prussian Blue Analogues: Template‐Free Synthesis and Sodium‐Ion Battery Applications
Authors: Yue Yanfeng , Binder Andrew J. , Guo Bingkun , Zhang Zhiyong , Qiao Zhen‐An , Tian Chengcheng , Dai Sheng
Published: February 2014

The synthesis of mesoporous Prussian blue analogues through a template‐free methodology and the application of these mesoporous materials as high‐performance cathode materials in sodium‐ion batteries is presented. Crystalline mesostructures were produced through a synergistically coupled nanocrystal formation and aggregation mechanism. As cathodes for sodium‐ion batteries, the Prussian blue analogues all show a reversible capacity of 65 mA h g−1 at low current rate and show excellent cycle stability. The reported method stands as an environmentally friendly and low‐cost alternative to hard or soft templating for the fabrication of mesoporous materials.
Redox‐Triggered CC Coupling of Diols and Alkynes: Synthesis of β,γ‐Unsaturated α‐Hydroxyketones and Furans by Ruthenium‐Catalyzed Hydrohydroxyalkylation
Authors: McInturff Emma L. , Nguyen Khoa D. , Krische Michael J.
Published: February 2014

Direct ruthenium‐catalyzed CC coupling of alkynes and vicinal diols to form β,γ‐unsaturated ketones occurs with complete levels of regioselectivity and good to complete control over the alkene geometry. Exposure of the reaction products to substoichiometric quantities of p‐toluenesulfonic acid induces cyclodehydration to form tetrasubstituted furans. These alkyne‐diol hydrohydroxyalkylations contribute to a growing body of merged redox‐construction events that bypass the use of premetalated reagents and, hence, stoichiometric quantities of metallic by‐products.
Blends of poly(3‐hydroxybutyrate) with poly(β‐alanine) and its derivatives
Authors: Çatıker Efkan , Sancaktar Erol
Published: February 2014

Nanofibers and films of poly(3‐hydroxybutyrate) (PHB)/nylon 3 [poly(β‐alanine) (N3)], PHB/poly(α‐methyl‐β‐alanine) (2mN3), and PHB/poly(β‐methyl‐β‐alanine) (3mN3) blends were prepared by electrospinning and film‐casting techniques, respectively. The miscibility of the blends was studied by Fourier transform infrared spectrometry, differential scanning calorimetry, thermogravimetric analysis, and X‐ray diffraction (XRD). The electrospinnability of the blends was studied by scanning electron microscopy. Some characteristic IR absorption bands of the components in the blends shifted gradually with changes in the compositions. The melting temperature and decomposition temperature of PHB decreased gradually with increasing fractions of N3, 2mN3, and 3mN3. The XRD spectra of all of the blends exhibited peaks with lower intensities compared to those of the neat species. The suppression of PHB crystallinity in the blends after blending was attributed to the disruption of its crystal lattice and the prevention of recrystallization of each component by means of other components and segmental interactions between the components in the amorphous phase. Thermal, spectroscopic, and optical analyses of the polymer blends revealed that the polymers were miscible with good compatibility, and this could have improved the scaffold properties of PHB. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40484.
Characterization of rheological and thermophysical properties of HDPE–wood composite
Authors: Tazi Mosfafa , Erchiqui Fouad , Godard François , Kaddami Hamid , Ajji Abdellah
Published: February 2014

The objective of this study is to develop a new biocomposite material with high deformation ability. In this regard, the thermal, rheological, and thermophysical properties of this new composite were characterized as a function of temperature and filler concentration. High density polyethylene (HDPE) was the matrix of this new composite which was reinforced with six sawdust concentrations 0%, 20%, 30%, 40%, 50%, and 60%. Maleic anhydride grafted polyethylene (PE‐g‐MA) was used as coupling agent. Addition of sawdust with PE‐g‐MA increased significantly the complex viscosity, the storage modulus (G′), and loss modulus (G″) of the matrix. The superposition of the complex viscosity curves using temperature dependent shift factor, allowed the construction of a viscosity master curve covering a wide range of temperatures. Arrhenius law was used for the relationship of the shift factor to temperature. Furthermore, method of Van Gurp and Palmen (tan delta vs. G*) is also used to control the time–temperature superposition. The experimental results can be well fitted with the cross rheological model which allowed the prediction of the thermorheological properties of the composites over a broad frequency range. By increasing wood concentration, both the activation energy and relaxation time for the biocomposites determined using, respectively, the Arrhenius law and the cole–cole rule increased. By contrast, specific heat of the matrix decreased with sawdust addition while its dimensional stability improved. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40495.
Predicting use of habitat patches by spawning horseshoe crabs (Limulus polyphemus) along a complex coastline with field surveys and geospatial analyses
Authors: Landi Alicia A. , Vokoun Jason C. , Howell Penelope , Auster Peter
Published: February 2014

This research described coastal habitat characteristics at a landscape scale and followed a geospatial modelling approach to predict the probability of habitat use by the population of Atlantic horseshoe crabs (Limulus polyphemus) in Long Island Sound (LIS, USA). This approach was developed to aid in decision‐making regarding management of horseshoe crab spawning locations.

Geospatial data layers were created within which beach slope, wave exposure, surface substrate type, and distance from offshore aggregations of crabs (i.e. hotspots) were summarized for beaches in the western, central, and eastern regions of the Connecticut coast of LIS.

Spawning abundances derived from field surveys conducted in May and June of 2009 and 2010 were used with remotely‐sensed habitat characteristics to develop a resource selection function from a candidate model set based on polytomous logistic regression.

A single best model (Akaike weight = 0.97) for predicting the probability of habitat use by spawning horseshoe crabs was selected using an information‐theoretic approach. The parameter estimates predicted a greater probability of habitat use with increasing slope, decreasing wave exposure, and decreasing distance from offshore hotspots.

Small ‘pocket’ beaches surrounded by rocky headlands, marshes, and developed areas are the typical habitat available to support horseshoe crab spawning in LIS. As spawning densities in LIS are relatively small and suitable spawning habitat is fragmented, geospatial methods are especially useful for identifying high‐use sites and maximizing the conservation value of management actions.

Copyright © 2014 John Wiley & Sons, Ltd.
Design, Synthesis, Antiviral, and Cytostatic Evaluation of Novel Isoxazolidine Analogs of Homonucleotides
Authors: Łysakowska Magdalena , Balzarini Jan , Piotrowska Dorota G.
Published: February 2014

Moderate diastereoselectivities (d.e. 2–62%) of isoxazolidine homonucleotides were observed for cycloadditions between N‐methyl‐C‐(diethoxyphosphoryl)nitrone and N‐allyl nucleobases, with trans‐isoxazolidines predominating. The stereochemistry of the substituted isoxazolidines was established based on 2D NOE experiments performed for uracil‐containing cycloadducts. The cis‐ and trans‐isoxazolidine phosphonates obtained herein were evaluated in vitro for activity against a broad range of DNA and RNA viruses. None of the compounds were endowed with antiviral activity at subtoxic concentrations, but some of them were found to inhibit the proliferation of L1210 cells with IC50 values in the range of 33–100 µM.
Porous Protein Crystals as Catalytic Vessels for Organometallic Complexes
Authors: Tabe Hiroyasu , Abe Satoshi , Hikage Tatsuo , Kitagawa Susumu , Ueno Takafumi
Published: February 2014

Porous protein crystals, which are protein assemblies in the solid state, have been engineered to form catalytic vessels by the incorporation of organometallic complexes. Ruthenium complexes in cross‐linked porous hen egg white lysozyme (HEWL) crystals catalyzed the enantioselective hydrogen‐transfer reduction of acetophenone derivatives. The crystals accelerated the catalytic reaction and gave different enantiomers based on the crystal form (tetragonal or orthorhombic). This method represents a new approach for the construction of bioinorganic catalysts from protein crystals.
The Influence of the Framework: An Anion‐Binding Study Using Fused [n]Polynorbornanes
Authors: Long Benjamin M. , Pfeffer Frederick M.
Published: February 2014

A series of bis‐thiourea‐functionalized [n]polynorbornane hosts (1–6) with increasing size were synthesized and their anion‐binding properties were evaluated by using 1H NMR spectroscopic titration and Job’s plot analysis. The larger bis‐thiourea‐[3]polynorbornane scaffolds 4 and 5 bound acetate in a 1:1 (cooperative) arrangement, whereas the corresponding smaller norbornane host 2, identical in preorganization, bound acetate in a 1:2 (independent) arrangement. In contrast, the size of the framework had no influence on the binding of dihydrogenphosphate. These results clearly highlight the subtle influence that the framework itself can have on host–guest interactions.
A stochastic multimodal reliable network design problem under adverse weather conditions
Authors: Uchida Kenetsu , Sumalee Agachai , Ho H. W.
Published: February 2014

This paper formulates a network design problem (NDP) for finding the optimal public transport service frequencies and link capacity expansions in a multimodal network with consideration of impacts from adverse weather conditions. The proposed NDP aims to minimize the sum of expected total travel time, operational cost of transit services, and construction cost of link capacity expansions under an acceptable level of variance of total travel time. Auto, transit, bus, and walking modes are considered in the multimodal network model for finding the equilibrium flows and travel times. In the proposed network model, demands are assumed to follow Poisson distribution, and weather‐dependent link travel time functions are adopted. A probit‐based stochastic user equilibrium, which is based on the perceived expected travel disutility, is used to determine the multimodal route of the travelers. This model also considers the strategic behavior of the public transport travelers in choosing their routes, that is, common‐line network. Based on the stochastic multimodal model, the mean and variance of total travel time are analytical estimated for setting up the NDP. A sensitivity‐based solution algorithm is proposed for solving the NDP, and two numerical examples are adopted to demonstrate the characteristics of the proposed model. Copyright © 2014 John Wiley & Sons, Ltd.
Choline transporter‐like proteins CTLs/SLC44 family as a novel molecular target for cancer therapy
Authors: Inazu Masato
Published: February 2014

Choline is essential for the synthesis of the major membrane phospholipid phosphatidylcholine (PC), the methyl donor betaine and the neurotransmitter acetylcholine (ACh). Elevated levels of choline and up‐regulated choline kinase activity have been detected in various cancers. Thus, the intracellular accumulation of choline through choline transporters is the rate‐limiting step in phospholipid metabolism and a prerequisite for cancer cell proliferation. Previous studies have demonstrated abnormalities in choline uptake and choline phospholipid metabolism in cancer cells using the imaging of cancer with positron emission tomography (PET) and magnetic resonance spectroscopy (MRS). The aberrant choline metabolism in cancer cells is strongly correlated with their malignant progression. Using quantitative real‐time PCR, the mRNA expression of choline transporters was measured, and it was found that choline transporter‐like proteins CTLs/SLC44 family are highly expressed in various cancer cell lines. Choline uptake through CTLs is associated with cell viability, and the functional inhibition of CTLs could promote apoptotic cell death. Furthermore, non‐neuronal cholinergic systems that include CTLs‐mediated choline transport are associated with cell proliferation and their inhibition promotes apoptotic cell death in colon cancer, small cell lung cancer and human leukemic T‐cells. The identification of this new CTLs‐mediated choline transport system provides a potential new target for cancer therapy. Copyright © 2014 John Wiley & Sons, Ltd.
Pharmacokinetics of tolbutamide and its metabolite 4‐hydroxy tolbutamide in poloxamer 407‐induced hyperlipidemic rats
Authors: Choi Mi Ran , Kwon Mi Hye , Cho Yong Yeon , Choi Hye Duck , Kim Yu Chul , Kang Hee Eun
Published: February 2014

Under hyperlipidemic conditions, there are likely to be alterations in the pharmacokinetics of CYP2C11 substrates following decreased expression of CYP2C11, which is homologous to human CYP2C9. The pharmacokinetics of tolbutamide (TB) and its metabolite 4‐hydroxy tolbutamide (4‐OHTB) were evaluated as a CYP2C11 probe after intravenous and oral administration of 10 mg/kg tolbutamide to poloxamer 407‐induced hyperlipidemic rats (HL rats). Changes in the expression and metabolic activity of hepatic CYP2C11 and the plasma protein binding of tolbutamide in HL rats were also evaluated. The total area under the plasma concentration–time curve (AUC) of tolbutamide in HL rats after intravenous administration was comparable to that in controls due to their comparable non‐renal clearance (CLNR). The free fractions of tolbutamide in plasma were comparable between the control and HL rats. The 4‐hydroxylated metabolite formation ratio (AUC4‐OHTB/AUCTB) in HL rats was significantly smaller than that in the control rats as a result of the reduced expression of hepatic CYP2C11 (by 15.0%) and decreased hepatic CLint (by 28.8%) for metabolism of tolbutamide to 4‐OHTB via CYP2C11. Similar pharmacokinetic changes were observed in HL rats after oral administration of tolbutamide. These findings have potential therapeutic implications, assuming that the HL rat model qualitatively reflects similar changes in patients with hyperlipidemia. Since other sulfonylureas in clinical use are substrates of CYP2C9, their hepatic CLint changes have the potential to cause clinically relevant pharmacokinetic changes in a hyperlipidemic state. Copyright © 2014 John Wiley & Sons, Ltd.
Effects of fluidity on the ensemble structure of a membrane embedded α‐helical peptide
Authors: Eagleburger Michael K. , Cooley Jason W. , JiJi Renee D.
Published: February 2014

Melittin, the main hemolytic component of honeybee venom, is unfolded in an aqueous environment and folds into an α‐helical conformation in a lipid environment. Membrane fluidity is known to affect the activity and structure of melittin. By combining two structurally sensitive optical methods, circular dichroism (CD) and deep‐ultraviolet resonance Raman spectroscopy (dUVRR), we have identified distinct structural fluctuations in melittin correlated with increased and decreased 1,2‐dimyristoyl‐sn‐glycero‐3‐phosphocholine bilayer fluidities. CD spectra have reduced intensity at temperatures above 22°C and high concentrations of the cholesterol analog 5α‐cholestan‐3β‐ol indicating distortions in the α‐helical structure under these conditions. No increase in the amide S is observed in the temperature‐dependent dUVRR spectra, suggesting an increase in 310‐helical structure with increasing temperatures above 22°C. However, incorporation of 25 mol% 5α‐cholestan‐3β‐ol resulted in a small increase in the amide S intensity indicating partial unfolding of melittin. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 895–902, 2014.
Randomized clinical trial of single- versus multi-incision laparoscopic cholecystectomy
Authors: Jørgensen L N , Rosenberg J , Al-Tayar H , Assaadzadeh S , Helgstrand F , Bisgaard T
Published: February 2014

Background

There are no randomized studies that compare outcomes after single-incision (SLC) and conventional multi-incision (MLC) laparoscopic cholecystectomy under an optimized perioperative analgesic regimen.

Methods

This patient- and assessor-blinded randomized three-centre clinical trial compared SLC and MLC in women admitted electively with cholecystolithiasis. Outcomes were registered on the day of operation (day 0), on postoperative days 1, 2, 3 and 30, and 12 months after surgery. Blinding of the patients was maintained until day 3. The primary endpoint was pain on movement measured on a visual analogue scale, reported repeatedly by the patient until day 3.

Results

The intention-to-treat population comprised 59 patients in the SLC and 58 in the MLC group. There was no significant difference between the groups with regard to any of the pain-related outcomes, on-demand administration of opioids or general discomfort. Median duration of surgery was 32·5 min longer in the SLC group (P < 0·001). SLC was associated with a reduced incidence of vomiting on day 0 (7 versus 22 per cent; P = 0·019). The incidences of wound-related problems were comparable. One patient in the SLC group experienced a biliary leak requiring endoscopic retrograde cholangiopancreatography. The rates of incisional hernia at 12-month follow-up were 2 per cent in both groups. Cosmetic rating was significantly improved after SLC at 1 and 12 months (P < 0·001).

Conclusion

SLC did not significantly diminish early pain in a setting with optimized perioperative analgesic patient care. SLC may reduce postoperative vomiting. Registration number: NCT01268748 (http://www.clinicaltrials.gov).
Risk factors for anastomotic leakage and leak-related mortality after colonic cancer surgery in a nationwide audit
Authors: Bakker I S , Grossmann I , Henneman D , Havenga K , Wiggers T
Published: February 2014

Background

Surgical resection with restoration of bowel continuity is the cornerstone of treatment for patients with colonic cancer. The aim of this study was to identify risk factors for anastomotic leakage (AL) and subsequent death after colonic cancer surgery.

Methods

Data were retrieved from the Dutch Surgical Colorectal Audit. Patients undergoing colonic cancer resection with creation of an anastomosis between January 2009 to December 2011 were included. Outcomes were AL requiring reintervention and postoperative mortality following AL.

Results

AL occurred in 7·5 per cent of 15 667 patients. Multivariable analyses identified male sex, high American Society of Anesthesiologists (ASA) fitness grade, extensive tumour resection, emergency surgery, and surgical resection types such as transverse resection, left colectomy and subtotal colectomy as independent risk factors for AL. A defunctioning stoma was created in a small group of patients, leading to a lower risk of leakage. The mortality rate was 4·1 per cent overall, and was significantly higher in patients with AL than in those without leakage (16·4 versus 3·1 per cent; P < 0·001). Multivariable analyses identified older age, high ASA grade, high Charlson score and emergency surgery as independent risk factors for death after AL. The adjusted risk of death after AL was twice as high following right compared with left colectomy.

Conclusion

The elderly and patients with co-morbidity have a higher risk of death after AL. Accurate preoperative patient selection, intensive postoperative surveillance for AL, and early and aggressive treatment of suspected leakage is important, especially in patients undergoing right colectomy.