bluuebunny/crossref_metadata_2025 huggingface dataset:
Geographically Related Variation in Epicuticular Wax Traits of Pinus nigra Populations from Southern Carpathians and Central Balkans – Taxonomic Considerations
Authors: Mitić Zorica S. , Zlatković Bojan K. , Jovanović Snežana Č. , Stojanović Gordana S. , Marin Petar D.
Published: June 2016

The chemical composition of epicuticular waxes of nine populations from three Pinus nigra J. F. Arnold subspecies (namely subsp. nigra, subsp. banatica (Borbás) Novák, and subsp. pallasiana (Lamb.) Holmboe) from Southern Carpathians and central Balkan Peninsula were analyzed using GC/MS and GC/FID chromatography, and multivariate statistical techniques with respect to biogeography and taxonomy. In the needle waxes, four primary alcohols and 14 n‐alkanes ranging from C21 to C33 were identified, and the most abundant compounds were the four odd‐numbered n‐alkanes C27, C25, C23, and C29. Multivariate statistical analyses (CDA and CA) have shown existence of three P. nigra groups and suggested clinal differentiation as a mechanism of genetic variation across a geographic area: the first group consisted of the southernmost populations of subsp. pallasiana from Macedonia, the second consisted of the northernmost subsp. banatica populations from Romania, while all populations in Serbia described as three different subspecies (nigra, banatica, and pallasiana) formed the third group together with subsp. nigra population from Bosnia and Herzegovina. According to simple linear regression, geographic latitude and four bioclimatic parameters were moderately correlated with the contents of epicuticular wax compounds that are important in population discrimination, while stepwise multiple regression showed that latitude participated in most of the regression models for predicting the composition of the epicuticular waxes. These results agree with CDA and CA analysis, and confirmed the possibility of recognition of fine geographic differentiation of the analyzed P. nigra populations.
Hepatoma‐derived growth factor promotes growth and metastasis of hepatocellular carcinoma cells
Authors: Yang Guang‐yun , Zhang Ai‐qun , Wang Jing , Li Chong‐hui , Wang Xian‐qiang , Pan Ke , Zhou Cheng , Dong Jia‐hong
Published: June 2016

We aimed to elucidate the effects of hepatoma‐derived growth factor (HDGF) on growth and metastasis of hepatocellular carcinoma (HCC) cells. Tissue microarrays with 236 HCC specimens and 18 extrahepatic metastases were utilized to detect the HDGF expression by immunohistochemistry. Meanwhile, HDGF expressions in HCC cell lines with different metastatic potentials were examined using immunofluorescence staining, real‐time PCR and western blotting. After HDGF silencing, the growth and metastatic potentials of HCC cells were evaluated by soft agar assay, invasion assay, together with tumorigenicity assay in nude mice. The gelatin zymography was performed by detecting MMP‐2 and MMP‐9 levels. Additionally, western blotting was conducted to determine the levels of total and phosphorylated ERK1/2, JNK, p38 and Akt. The results showed that HDGF was overexpressed in HCC metastasis tumour, and the expression increased with the differentiation degree of tumours (Grade I 44.0%, Grade II 48.4% and Grade III 65.6%). Consistently, HDGF levels were positively associated with the metastatic capability of HCC cells (MHCC97L < MHCC97H < HCCLM3). The growth and metastasis were suppressed by HDGF‐siRNA. Gelatinolytic activities were enhanced in the three metastatic HCC cell lines, but had no significant difference among them. The tumourigenicity and metastatic capability of HCCLM3 cells in nude mice were inhibited after silencing HDGF. Meanwhile, HDGF‐siRNA specifically suppressed the total and phosphorylated protein levels of ERK1/2, while not JNK, p38 and Akt. In conclusion, HDGF was overexpressed in HCC patients and cells, and HDGF might be closely correlated with HCC metastasis via regulating ERK signalling pathway. Copyright © 2016 John Wiley & Sons, Ltd.
Stereospecific Effects of Oxygen‐to‐Sulfur Substitution in DNA Phosphate on Ion Pair Dynamics and Protein–DNA Affinity
Authors: Nguyen Dan , Zandarashvili Levani , White Mark A. , Iwahara Junji
Published: June 2016

Oxygen‐to‐sulfur substitutions in DNA phosphate often enhance affinity for DNA‐binding proteins. Our previous studies have suggested that this effect of sulfur substitution of both OP1 and OP2 atoms is due to an entropic gain associated with enhanced ion pair dynamics. In this work, we studied stereospecific effects of single sulfur substitution of either the OP1 or OP2 atom in DNA phosphate at the Lys57 interaction site of the Antennapedia homeodomain–DNA complex. Using crystallography, we obtained structural information on the RP and SP diastereomers of the phosphoromonothioate and their interaction with Lys57. Using fluorescence‐based assays, we found significant affinity enhancement upon sulfur substitution of the OP2 atom. Using NMR spectroscopy, we found significant mobilization of the Lys57 side‐chain NH3+ group upon sulfur substitution of the OP2 atom. These data provide further mechanistic insights into the affinity enhancement by oxygen‐to‐sulfur substitution in DNA phosphate.
Branched Tungsten Oxide Nanorod Arrays Synthesized by Controlled Phase Transformation for Solar Water Oxidation
Authors: Zhang Tao , Wang Lu , Su Jinzhan , Guo Liejin
Published: June 2016

Branched (NH4)0.33⋅WO3 nanorods have been successfully synthesized by applying a simple hydrothermal approach with ammonium oxalate as capping agents. After annealing them in different atmospheres, the (NH4)0.33⋅WO3 nanorods were converted to WO3 nanorods. Atmosphere‐dependent morphology evolution and phase transformation by annealing of (NH4)0.33⋅WO3 were observed. The branched WO3 nanorods produce a higher photoelectrochemical activity than the bare WO3 nanorods without branches obtained under similar conditions, and the improvement of efficiency by branched nanorods was ascribed to the better light‐trapping characteristics and increase in surface area, which facilitates holes transfer at the WO3/electrolyte interface. The possible formation mechanisms of branched nanorods have been explored and the results show that the synergistic interaction between ammonium ion (NH4+) and acetate ion (−COO−) contributes to the formation of branched (NH4)0.33⋅WO3 nanorods.
Cyclization of 2‐Ethynylphenyl Vinyl Ether Catalyzed by a Ruthenium Complex: Mechanism of Catalytic Cyclization and Stoichiometric Cycloisomerization
Authors: Chen Chi‐Ren , Lai Ying‐Xuan , Wu Rong‐Yu , Liu Yi‐Hung , Lin Ying‐Chih
Published: June 2016

Catalytic cyclization reactions and new stoichiometric skeletal rearrangement cycloisomerizations of 2‐ethynylphenyl vinyl ethers containing methyl substituents on the vinyl groups by using [Ru]Cl {[Ru]=Cp(PPh3)2Ru, Cp=η5‐cyclopentadienyl} were observed in MeOH and CH2Cl2, respectively. In MeOH, the catalytic cyclization of three different enynes gave the corresponding benzoxepine derivatives in high yields in each case. Interestingly, in the stoichiometric reactions of [Ru]Cl with enynes, two unprecedented rearrangements of enynes were observed in CH2Cl2. The presence of a methyl group in the vinyl unit plays a critical role in choosing one of the double bonds of the vinylidene ligand, that is, the Ru=Cα or the Cα=Cβ bond, for the [2+2] cycloaddition in the cycloisomerization processes. Structure determination by single‐crystal X‐ray diffraction analysis along with various isotope studies corroborated the proposed mechanisms.
Design, Synthesis, EPR‐Studies and Conformational Bias of Novel Spin‐Labeled DCC‐Analogues for the Highly Regioselective Labeling of Aliphatic and Aromatic Carboxylic Acids
Authors: Gölz Jan Philipp , NejatyJahromy Yaser , Bauer Mirko , Muhammad Ashraf , Schnakenburg Gregor , Grimme Stefan , Schiemann Olav , Menche Dirk
Published: June 2016

Novel types of spin‐labeled N,N′‐dicyclohexylcarbodiimides (DCC) are reported that bear a 2,2,6,6‐tetramethylpiperidinyloxyl (TEMPO) residue on one side and different aromatic and aliphatic cyclohexyl analogues on the other side of the diimide core. These readily available novel reagents add efficiently to aliphatic and aromatic carboxylic acids, forming two possible spin‐labeled amide derivatives with different radical distances of the resulting amide. The addition of aromatic DCC analogues proceeds with excellent selectivity, giving amides where the carboxylic acid is exclusively connected to the aromatic residue, while little or no selectivity was observed for the aliphatic congeners. The usefulness of these adducts in structural studies was demonstrated by EPR (electron paramagnetic resonance) measurements of biradical adducts of biphenyl‐4,4′‐dicarboxylic acids. These analyses also reveal high degrees of conformational bias for aromatic DCC derivatives, which further underlines the powerfulness of these novel reagents. This observation was further corroborated by quantum chemical calculations, giving a detailed understanding of the structural dynamics, while detailed information on the solid state structure of all novel reagents was obtained by X‐ray structure analyses.
The Mechanism of Phosphonium Ylide Alcoholysis and Hydrolysis: Concerted Addition of the O−H Bond Across the P=C Bond
Authors: Byrne Peter A. , Gilheany Declan G.
Published: June 2016

The previous work on the hydrolysis and alcoholysis reactions of phosphonium ylides is summarized and reviewed in the context of their currently accepted mechanisms. Several experimental facts relating to ylide hydrolysis and to salt and ylide alcoholysis are shown to conflict with those mechanisms. In particular, we demonstrate that the pKa values of water and alcohols are too high in organic media to bring about protonation of ylide. Therefore, we propose concerted addition of the water or alcohol O−H bond across the ylide P=C bond. In support of this, we provide NMR spectroscopic evidence for equilibrium between ylide and aclohol that does not require the involvement of phosphonium hydroxide. We report the first P‐alkoxyphosphorane to be characterised by NMR spectroscopy that does not undergo exchange on an NMR timescale. Two‐dimensional NMR spectroscopic techniques have been applied to the characterisation to P‐alkoxyphosphoranes for the first time.
First Atroposelective Total Synthesis of Enantiomerically Pure Ancistrocladidine and Ancistrotectorine
Authors: Bringmann Gerhard , Manchala Narasimhulu , Büttner Tobias , Hertlein‐Amslinger Barbara , Seupel Raina
Published: June 2016

The first regio‐ and stereoselective total synthesis of the axially chiral 7,3′‐coupled naphthylisoquinoline alkaloids ancistrocladidine (1) and ancistrotectorine (2) has been described. Both possess a 7,3′‐coupled axis, which before now, was difficult to attain synthetically. Moreover, target 2 has a sensitive relative cis‐array of the two methyl groups at C1 and C3 in the tetrahydroisoquinoline part. The key step in the chosen strategy was the construction of the biaryl axis in accordance with the “lactone method”: the two molecular halves, which were activated in an “inverse‐halogenated” form, were prefixed by an ester bridge, followed by intramolecular coupling, and atroposelective cleavage of the lactone auxiliary bridge delivered the desired biaryl scaffold.
Experiment‐Driven Modeling of Crystalline Phosphorus Nitride P3N5: Wide‐Ranging Implications from a Unique Structure
Authors: Tolhurst Thomas M. , Braun Cordula , Boyko Teak D. , Schnick Wolfgang , Moewes Alexander
Published: June 2016

Nitridophosphates have emerged as advanced materials due to their structural variability and broad technical applicability. Their binary parent compound P3N5, a polymeric network of corner‐ and edge‐sharing PN4 tetrahedra with N and N sites, is a particularly interesting example. We present a study of the band gap and electronic structure of α‐P3N5 by using soft X‐ray spectroscopy measurements and DFT calculations. The band gap, which is crucial for all applications, is measured to be 5.87±0.20 eV. This agrees well with the calculated, indirect band gap of 5.21 eV. The density of states are found to show dramatic variation between the nonequivalent N sites and a high degree of covalency. Coupled to these results is what is, to our knowledge, the largest core hole shift reported to date for a soft X‐ray absorption spectrum. We propose an intuitive bonding scheme for α‐P3N5 that explains the observed band gap and unique density of states, while providing a framework for predicting these properties in known and yet to be discovered PN compounds. We briefly consider the implications of these results for new low‐dimensional P and PN materials, which alongside graphene, could become important materials for nanoelectronics.
Towards Safer Rocket Fuels: Hypergolic Imidazolylidene‐Borane Compounds as Replacements for Hydrazine Derivatives
Authors: Huang Shi , Qi Xiujuan , Liu Tianlin , Wang Kangcai , Zhang Wenquan , Li Jianlin , Zhang Qinghua
Published: June 2016

Currently, toxic and volatile hydrazine derivatives are still the main fuel choices for liquid bipropellants, especially in some traditional rocket propulsion systems. Therefore, the search for safer hypergolic fuels as replacements for hydrazine derivatives has been one of the most challenging tasks. In this study, six imidazolylidene‐borane compounds with zwitterionic structure have been synthesized and characterized, and their hypergolic reactivity has been studied. As expected, these compounds exhibited fast spontaneous combustion upon contact with white fuming nitric acid (WFNA). Among them, compound 5 showed excellent integrated properties including wide liquid operating range (−70–160 °C), superior loading density (0.99 g cm−3), ultrafast ignition delay times with WFNA (15 ms), and high specific impulse (303.5 s), suggesting promising application potential as safer hypergolic fuels in liquid bipropellant formulations.
[40]π Fused and Nonfused Core‐Modified Nonaphyrins: Syntheses and Structural Diversity
Authors: Ghosh Arindam , Srinivasan A. , Suresh Cherumuttathu H. , Chandrashekar Tavarekere K.
Published: June 2016

The synthesis of fused and nonfused core‐modified 40π nonaphyrins are reported. Spectroscopic and X‐ray structural studies reveal a twisted figure‐eight conformation in the freebase form that is nonaromatic. Structural changes occur, from figure‐eight to open extended conformation, upon protonation, thereby adopting 4nπ Hückel antiaromatic character, which is reflected in spectroscopic and theoretical studies. Such a structural change also induces ring inversions of specific heterocyclic rings by 180°.
Noncovalent Substrate‐Directed Enantioselective Heck Reactions: Synthesis of S‐ and P‐Stereogenic Heterocycles
Authors: de Azambuja Francisco , Carmona Rafaela C. , Chorro Tomaz H. D. , Heerdt Gabriel , Correia Carlos Roque D.
Published: June 2016

S‐ and P‐Stereogenic heterocycles were synthesized by a remarkably simple enantioselective Heck desymmetrization reaction based on the unprecedented noncovalent directing effect of S=O and P=O functionalities. Selected prochiral symmetric substrates were efficiently arylated using the recently disclosed chiral PyraBOx ligand under mild and open‐flask reaction conditions. Several five‐membered aryl‐ sulfones, sulfoxides, and phosphine oxides were synthesized in good to excellent yields, in good to high diastereoselectivity, and enantiomeric ratios up to 98:2. Theoretical calculations also support the noncovalent directing effect of the S=O and P=O functionalities during the arylation process.
Nickel‐Catalyzed Cross‐Electrophile Coupling with Organic Reductants in Non‐Amide Solvents
Authors: Anka‐Lufford Lukiana L. , Huihui Kierra M. M. , Gower Nicholas J. , Ackerman Laura K. G. , Weix Daniel J.
Published: June 2016

Cross‐electrophile coupling of aryl halides with alkyl halides has thus far been primarily conducted with stoichiometric metallic reductants in amide solvents. This report demonstrates that the use of tetrakis(dimethylamino)ethylene (TDAE) as an organic reductant enables the use of non‐amide solvents, such as acetonitrile or propylene oxide, for the coupling of benzyl chlorides and alkyl iodides with aryl halides. Furthermore, these conditions work for several electron‐poor heterocycles that are easily reduced by manganese. Finally, we demonstrate that TDAE addition can be used as a control element to ‘hold’ a reaction without diminishing yield or catalyst activity.
Chiral HPLC Separation, Absolute Structural Elucidation, and Determination of Stereochemical Stability of trans‐Bis[2‐(2‐pyridinyl)aminophenolato] Cyclotriphosphazene
Authors: Kajiyama Kazumasa , Setone Yuki , Aoyagi Kouki , Yuge Hidetaka
Published: June 2016

Chiral high‐performance liquid chromatography (HPLC) separation of trans‐bis[2‐(2‐pyridyl)aminophenolato] dichlorocyclotriphosphazene 1 was achieved and the absolute configuration of (+)-1 was assigned to be S,S by single‐crystal X‐ray structural analysis. The optically pure 1,2‐diphenyl‐1,2‐ethanediolate derivatives (+)‐2a and (−)‐2b were synthesized by the reactions of (+)-1 and (-)-1 with (R,R)‐hydrobenzoin, respectively, in refluxing toluene in the presence of an excess amount of triethylamine and a catalytic amount of 4‐(dimethylamino)pyridine. The racemization of the enantiomers of 1 and the epimerization of diastereomers of 2 were not observed in refluxing toluene neither under acidic nor basic conditions. The stereochemistry of (+)-1 was confirmed by the crystal structure of (+)‐2a and bis[(4‐methyl‐2‐pyridyl)oxy]cyclotriphosphazene (+)-3 derived from (+)-1. Chirality 28:556–561, 2016. © 2016 Wiley Periodicals, Inc.
Imaging the Bonds of Dehalogenated Benzene Radicals on Cu(111) and Au(111)
Authors: Simic‐Milosevic Violeta , Mehlhorn Michael , Morgenstern Karina
Published: June 2016

Dissociative adsorption of doubly substituted benzene molecules leads to formation of benzyne radicals. In this study, co‐adsorbed hydrogen molecules are used in scanning tunneling hydrogen microscopy to enhance the contrast of the meta‐ and the para‐isomers of these radicals on Cu(111) and Au(111). Up to three hydrogen molecules are attached to one radical. One hydrogen molecule reveals the orientation of the carbon ring and its adsorption site, allowing discrimination between the two radicals. Two hydrogen molecules reflect the bond picture of the carbon skeleton and reveals that adsorption on Cu(111) distorts the meta‐ isomer differently from its gas‐phase distortion. Three hydrogen molecules allow us to determine the bond picture of a minor species.
Gadolinium(III)‐Based Porous Luminescent Metal–Organic Frameworks for Bimodal Imaging
Authors: Kundu Tanay , Mitra Shouvik , Díaz Díaz David , Banerjee Rahul
Published: June 2016

GdIII‐based metal–organic frameworks, Gd‐pDBI‐1 and Gd‐pDBI‐2, have been synthesized using the linker pDBI (pDBI=1,4‐bis(5‐carboxy‐1H‐benzimidazole‐2yl)benzene). They exhibited structural diversity due to subtle change in reaction constituents. Owing to the judicious choice of the fluorescent linker, the materials could be used for bimodal imaging (fluorescent and magnetic resonance) and displayed a modest T1 relaxivity value.
Heterogeneity in readouts of canonical wnt pathway activity within intestinal crypts
Authors: Li Ning , Yousefi Maryam , Nakauka‐Ddamba Angela , Tobias John W. , Jensen Shane T. , Morrisey Edward E. , Lengner Christopher J.
Published: June 2016

Background: Canonical Wnt pathway signaling is necessary for maintaining the proliferative capacity of mammalian intestinal crypt base columnar stem cells (CBCs). Furthermore, dysregulation of the Wnt pathway is a major contributor to disease, including oncogenic transformation of the intestinal epithelium. Given the critical importance of this pathway, numerous tools have been used as proxy measures for Wnt pathway activity, yet the relationship between Wnt target gene expression and reporter allele activity within individual cells at the crypt base remains unclear. Results: Here, we describe a novel Axin2‐CreERT2‐tdTomato allele that efficiently marks both WntHigh CBCs and radioresistant reserve intestinal stem cells. We analyze the molecular and functional identity of Axin2‐CreERT2‐tdTomato‐marked cells using single cell gene expression profiling and tissue regeneration assays and find that Axin2 reporter activity does not necessarily correlate with expression of Wnt target genes and, furthermore, that Wnt target genes themselves vary in their expression patterns at the crypt base. Conclusions: Wnt target genes and reporter alleles can vary greatly in their cell‐type specificity, demonstrating that these proxies cannot be used interchangeably. Furthermore, Axin2‐CreERT2‐tdTomato is a robust marker of both active and reserve intestinal stem cells and is thus useful for understanding the intestinal stem cell compartment. Developmental Dynamics 245:822–833, 2016. © 2016 Wiley Periodicals, Inc.
Somatic growth dynamics of West Atlantic hawksbill sea turtles: a spatio‐temporal perspective
Authors: Bjorndal Karen A. , Chaloupka Milani , Saba Vincent S. , Diez Carlos E. , van Dam Robert P. , Krueger Barry H. , Horrocks Julia A. , Santos Armando J. B. , Bellini Cláudio , Marcovaldi Maria A. G. , Nava Mabel , Willis Sue , Godley Brendan J. , Gore Shannon , Hawkes Lucy A. , McGowan Andrew , Witt Matthew J. , Stringell Thomas B. , Sanghera Amdeep , Richardson Peter B. , Broderick Annette C. , Phillips Quinton , Calosso Marta C. , Claydon John A. B. , Blumenthal Janice , Moncada Felix , Nodarse Gonzalo , Medina Yosvani , Dunbar Stephen G. , Wood Lawrence D. , Lagueux Cynthia J. , Campbell Cathi L. , Meylan Anne B. , Meylan Peter A. , Burns Perez Virginia R. , Coleman Robin A. , Strindberg Samantha , Guzmán‐H. Vicente , Hart Kristen M. , Cherkiss Michael S. , Hillis‐Starr Zandy , Lundgren Ian F. , Boulon Ralf H. , Connett Stephen , Outerbridge Mark E. , Bolten Alan B.
Published: June 2016

Somatic growth dynamics are an integrated response to environmental conditions. Hawksbill sea turtles (Eretmochelys imbricata) are long‐lived, major consumers in coral reef habitats that move over broad geographic areas (hundreds to thousands of kilometers). We evaluated spatio‐temporal effects on hawksbill growth dynamics over a 33‐yr period and 24 study sites throughout the West Atlantic and explored relationships between growth dynamics and climate indices. We compiled the largest ever data set on somatic growth rates for hawksbills – 3541 growth increments from 1980 to 2013. Using generalized additive mixed model analyses, we evaluated 10 covariates, including spatial and temporal variation, that could affect growth rates. Growth rates throughout the region responded similarly over space and time. The lack of a spatial effect or spatio‐temporal interaction and the very strong temporal effect reveal that growth rates in West Atlantic hawksbills are likely driven by region‐wide forces. Between 1997 and 2013, mean growth rates declined significantly and steadily by 18%. Regional climate indices have significant relationships with annual growth rates with 0‐ or 1‐yr lags: positive with the Multivariate El Niño Southern Oscillation Index (correlation = 0.99) and negative with Caribbean sea surface temperature (correlation = −0.85). Declines in growth rates between 1997 and 2013 throughout the West Atlantic most likely resulted from warming waters through indirect negative effects on foraging resources of hawksbills. These climatic influences are complex. With increasing temperatures, trajectories of decline of coral cover and availability in reef habitats of major prey species of hawksbills are not parallel. Knowledge of how choice of foraging habitats, prey selection, and prey abundance are affected by warming water temperatures is needed to understand how climate change will affect productivity of consumers that live in association with coral reefs.
Effects of temporal variation in temperature and density dependence on insect population dynamics
Authors: Haridas C. V. , Meinke Lance J. , Hibbard Bruce E. , Siegfried Blair D. , Tenhumberg Brigitte
Published: June 2016

Understanding the effects of environmental variation on insect populations is important in light of predictions about increasing climatic variability. This paper uses the univoltine western corn rootworm (WCR, Diabrotica virgifera virgifera LeConte) as a case study and employs deterministic and stochastic modeling to evaluate how insect population dynamics is shaped by density‐dependent survival and annual variation in temperature, which are key in regulating insect populations. Field data showed that larval survival varied significantly between years but was constant for a range of densities. Survival dropped only beyond a threshold density, a feature resembling generalized Ricker functions used in modeling density‐dependent survival due to scramble competition for resources. We used soil temperature data for 20 yr to model annual variation in developmental time and survival. The deterministic model, where the developmental time was same across years, showed that though survival was high and did not change for a range of densities (i.e., density‐independent survival), predicted densities were large enough that strong density dependence could occur in the field (i.e., predicted densities fall in the region where survival drops sharply) and that populations could exhibit stable equilibrium, cycles, etc. Interestingly, populations with lower density‐independent survival were less likely to produce stable equilibrium compared to populations with higher density‐independent survival. We found that population densities were at stable equilibrium when both mean developmental time and fertility were relatively low or when developmental time and fertility were relatively high. This in turn implies that, in warmer regions, where mean developmental time will be lower, stability is more likely for insect populations with low fertility; species in warmer regions will experience cyclical and unstable dynamics when fertility is high. While increase in the mean developmental time reduces overall survival, increasing variation in developmental time could increase mean survival, a consequence of the Jensen's inequality, since survival was a concave decreasing function of developmental time. Hence, both mean and variability in temperature affect the dynamics of insect populations. Finally, we found that stochastic variation in soil temperature produced large variation in predicted population densities that could potentially enhance or diminish the effect of density dependence.
Mapping for coral reef conservation: comparing the value of participatory and remote sensing approaches
Authors: Selgrath Jennifer C. , Roelfsema Chris , Gergel Sarah E. , Vincent Amanda C. J.
Published: June 2016

Detailed habitat maps are critical for conservation planning, yet for many coastal habitats only coarse‐resolution maps are available. As the logistic and technological constraints of habitat mapping become increasingly tractable, habitat map comparisons are warranted. Here we compare two mapping approaches: local environmental knowledge (LEK) obtained from interviews; and remote sensing analysis (RS) of high spatial resolution satellite imagery (2.0 m pixel) using object‐based image analysis. For a coral reef ecosystem, we compare the accuracy of these two approaches for mapping shallow seafloor habitats and contrast their characterization of habitat area and seascape connectivity. We also explore several implications for conservation planning. When evaluated using independent ground verification data, LEK‐derived maps achieved a lower overall accuracy than RS‐derived maps (LEK: 66%; RS: 76%). A comparison of mapped habitats found low overall agreement between LEK and RS maps. The RS map identified 5.4 times more habitat edges (the border between adjacent habitat classes) and 3.7–6.4 times greater seascape connectivity. Since the spatial arrangement of habitats affects many species (e.g., movement, predation risk), such discrepancies in landscape metrics are important to consider in conservation planning. Our results help identify strengths and weakness of both mapping approaches for conservation planning. Because RS provided a more accurate estimate of habitat distributions, it would be better for conservation planning for species sensitive to fine‐spatial scale seascape patterns (e.g., habitat edges), whereas LEK is more cost effective and appropriate for mapping coarse habitat patterns. Goals for maps used in conservation should be identified early in their development.
Metabolic programming in chronically stimulated T cells: Lessons from cancer and viral infections
Authors: Bettonville Marie , D'Aria Stefania , Braun Michel Y.
Published: June 2016

T‐cell metabolism is central to the shaping of a successful immune response. However, there are pathological situations where T cells are rendered dysfunctional and incapable of eliminating infected or transformed cells. Here, we review the current knowledge on T‐cell metabolism and how persistent antigenic stimulation, in the form of cancer and chronic viral infection, modifies both metabolic and functional pathways in T cells.
Exercise increases pressure pain tolerance but not pressure and heat pain thresholds in healthy young men
Authors: Vaegter H.B. , Hoeger Bement M. , Madsen A.B. , Fridriksson J. , Dasa M. , Graven‐Nielsen T.
Published: June 2016

Background

Exercise causes an acute decrease in the pain sensitivity known as exercise‐induced hypoalgesia (EIH), but the specificity to certain pain modalities remains unknown. This study aimed to compare the effect of isometric exercise on the heat and pressure pain sensitivity.

Methods

On three different days, 20 healthy young men performed two submaximal isometric knee extensions (30% maximal voluntary contraction in 3 min) and a control condition (quiet rest). Before and immediately after exercise and rest, the sensitivity to heat pain and pressure pain was assessed in randomized and counterbalanced order. Cuff pressure pain threshold (cPPT) and pain tolerance (cPTT) were assessed on the ipsilateral lower leg by computer‐controlled cuff algometry. Heat pain threshold (HPT) was recorded on the ipsilateral foot by a computer‐controlled thermal stimulator.

Results

Cuff pressure pain tolerance was significantly increased after exercise compared with baseline and rest (p < 0.05). Compared with rest, cPPT and HPT were not significantly increased by exercise. No significant correlation between exercise‐induced changes in HPT and cPPT was found. Test–retest reliability before and after the rest condition was better for cPPT and CPTT (intraclass correlation > 0.77) compared with HPT (intraclass correlation = 0.54).

Conclusions

The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the pain threshold. These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain.

Significance

The effect of isometric exercise on pain tolerance may be relevant for patients in chronic musculoskeletal pain as a pain‐coping strategy.

What does this study add?

The results indicate that hypoalgesia after submaximal isometric exercise is primarily affecting tolerance of pressure pain compared with the heat and pressure pain threshold.

These data contribute to the understanding of how isometric exercise influences pain perception, which is necessary to optimize the clinical utility of exercise in management of chronic pain.
Glycerol and Methanol Electro‐oxidation at Pt/C‐ITO under Alkaline Condition
Authors: Ottoni Cristiane Angélica , Ramos Carlos Eduardo Domingues , Gomes da Silva Sirlane , Spinacé Estevan Vitorio , Brambilla de Souza Rodrigo Fernando , Neto Almir Oliveira
Published: June 2016

A physical mixture composed by carbon Vulcan XC 72 and indium tin oxide (ITO) with different ratios (85 : 15; 50 : 50; 85 : 15) was used as support for platinum nanoparticles synthesis by borohydride reduction method. The characterization of this electrocatalyst was performed by transmission electron microscopy (TEM), X‐ray diffraction (XRD), electrochemical techniques cyclic voltammetry (CV), chronoamperometry and performance test on direct alkaline glycerol/methanol fuel cell (DGFC/DMFC). According to TEM micrographs, Pt/C‐ITO nanoparticles analysis revealed the presence of large agglomerations of particles. Moreover, it was possible to observe Pt deposition on ITO and also in the carbon surface. The electrochemical studies showed that Pt/C‐ITO (85 : 15) had superior performance for glycerol electro‐oxidation, whereas Pt/C‐ITO (15 : 85) was the most promising in the methanol oxidation. A comparative study using direct alkaline fuel cells revealed Pt‐C‐ITO (15 : 85) electrocatalyst to be the best material for glycerol and methanol oxidation, specifically when being at open circuit potential about 0.95 V, maximum power density of 16 mW cm−2 for glycerol and circuit potential 0.95 V, and maximum power density of approximately 20 mW cm−2 for methanol.
Non‐enzymatic Amperometric Glucose Sensor Based on Copper Nanowires Decorated Reduced Graphene Oxide
Authors: Ju Lele , Wu Guosong , Lu Biao , Li Xiaoyun , Wu Huaping , Liu Aiping
Published: June 2016

A nanocomposite consisting of one‐dimensional copper nanowires and two‐dimensional reduced graphene oxide nanosheets (CuNWs/rGO) was synthesized by a simple one‐step wet‐chemical synthetic process. The Cu NWs anchored onto the rGO nanosheets with wrinkles and folds had a smooth surface. The CuNWs/rGO hybrids exhibited excellent electrocatalytic activity toward glucose oxidation due to the superior conductivity along one‐dimensional direction and excellent catalytic activity of Cu NWs and rapid electron transfer in the two‐dimensional rGO sheets. A wide linear range up to 11 mM, high sensitivity (1625 µA/(mM ⋅ cm2)), low detection limit (0.2 µM) and fast response (<2 s) to glucose oxidation were obtained under a working potential of 0.58 V for the hybrid with optimized Cu/rGO mass ratio in the alkaline solution. Furthermore, the CuNWs/rGO composites displayed high selectivity to glucose and resistance against poisoning by commonly interfering species such as ascorbic acid, dopamine, uric acid, acetamidophenol and some carbohydrates. The CuNWs/rGO hybrids with good reproducibility, stability and poisoning resistance to chloride ions were therefore promising for the potential application as non‐enzymatic amperometric glucose sensors with improved electrochemical performances.
Electrochemical Behaviour of Nitrobenzene, Nitrosobenzene, Azobenzene, and Azoxybenzene on Hg, Pt, Cu, and Ni Electrodes in Aprotic Medium
Authors: Huang Youqin , Lessard Jean
Published: June 2016

The electrochemical behaviour of nitrobenzene and other members of the nitrobenzene family (nitrosobenzene, azoxybenzene, azobenzene) has been investigated in DMF/TEAP by cyclic voltammetry, polarography, and controlled potential electrolysis at mercury, platinum, copper, and nickel cathodes. At the four electrodes, nitrobenzene and the other members of the family are reduced to aniline via hydrazobenzene upon exhaustive electrolysis at −2.35 V vs. Ag/AgNO3 (0,05 M). The electrochemical reversibility of the nitrobenzene/nitrobenzene radical anion and of the azoxybenzene/azoxybenzene radical anion couples is decreased by the presence of oxides at the surface of copper and nickel. The presence of oxides has little influence on the reversibility of the nitrosobenzene/nitrosobenzene radical anion and azobenzene/azobenzene radical anion couples.
Electrogeneration of O2.− and H2O2 Using Polymer‐modified Microelectrodes in the Environment of Living Cells
Authors: Dongmo Saustin , Leyk Janina , Dosche Carsten , Richter‐Landsberg Christiane , Wollenberger Ulla , Wittstock Gunther
Published: June 2016

Microelectrodes modified with electropolymerized plumbagin (PLG) were used for the generation of superoxide radical (O2.−) and hydrogen peroxide (H2O2) during oxygen reduction reaction (ORR) in an aqueous medium, specifically in serum‐free cell culture media. This is enabled by the specific design of a polymer film on the microelectrode. The generation and diffusion of O2.− during electrocatalytic ORR at a positionable PLG polymer‐modified microelectrode was followed by fluorescence microscopy with the selective dye 4‐chloro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐Cl) and by amperometric detection using a cytochrome c‐modified electrode at +0.13 V. H2O2 production, either by direct oxygen reduction or as product of O2.− disproportionation, was monitored by the reaction with Amplex UltraRed. The PLG polymer‐modified microelectrodes were used to expose mammalian B6‐RPE07 retinal cells to defined local fluxes of reactive oxygen species (ROS), and cellular responses and morphological alterations were observed. The use of a controllable source of ROS opens many possibilities to study how living cells respond to the presence of a certain flux of specific ROS.
The care needs and experiences with the use of services of people with young‐onset dementia and their caregivers: a systematic review
Authors: Millenaar Joany K. , Bakker Christian , Koopmans Raymond T. C. M. , Verhey Frans R. J. , Kurz Alexander , de Vugt Marjolein E.
Published: June 2016

Objective

In this review, the care needs and experiences with the use of available services of individuals with young‐onset dementia (YOD) and their caregivers were investigated. This knowledge is an important prerequisite for the development of appropriate interventions and personalized care to address their specific needs and problems.

Design

A systematic literature search was performed in PubMed, Psycinfo and Cinahl. A quality checklist for observational and qualitative studies was used to appraise the methodological quality of the studies.

Results

Twenty‐seven studies were included, and a synthesis of the literature revealed six themes. The first theme concerned problems in the diagnostic period. Early recognition and referral was reported as an essential area that required improvement in order to obtain appropriate help in time. The second theme discussed the need for information about YOD and the availability of care throughout the caregiving trajectory. The third theme described barriers in access to care that hindered caregivers in finding the right services. The fourth theme showed the availability of appropriate services and specific unmet needs. The fifth theme illustrated that behavioural and personality changes pose a significant challenge for caregivers and other family members. The last theme showed the profound impact of YOD on caregivers.

Conclusions

The literature indicates that people with YOD and their caregivers face a wide range of difficulties during the disease process. The reviewed studies provide an important foundation for knowledge and awareness about the specific care needs and experiences of people with YOD and their caregivers. Copyright © 2016 John Wiley & Sons, Ltd.
Effect of surgical intervention on circulating tumor cells in patients with squamous cell carcinoma of the head and neck using a negative enrichment technology
Authors: Jatana Kris R. , Balasubramanian Priya , McMullen Kyle P. , Lang Jas C. , Teknos Theodoros N. , Chalmers Jeffrey J.
Published: June 2016

Background

The purpose of this study was to investigate the impact of surgical intervention on detection of circulating tumor cells (CTCs) in patients with squamous cell carcinoma of the head and neck (SCCHN.)

Methods

We utilized a negative depletion technique to identify cytokeratin (CK)‐positive CTCs. The numbers of CTCs immediately before and after surgical resection were compared.

Results

Seventy‐six blood samples from 38 patients with SCCHN were examined. Seventy‐nine percent of the patients had CTCs detected before and after surgery. A total of 7.89% had no CTCs before surgery, yet had CTCs identified after surgery. Overall, 60.5% of patients had an increased number of CTCs/mL after surgery with a mean increase of 6.63‐fold. A statistically significant increase in CTCs was seen after surgery (p = .02).

Conclusion

The timing of sample collection in patients with SCCHN who have surgical intervention can potentially impact the number of CTCs identified. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1799–1803, 2016
Bioguided Isolation and Antiproliferative Activity of Constituents fromSmilax korthalsiiA.D.C. Leaves
Authors: Hamid Abdulmumeen A. , Aiyelaagbe Olapeju O. , Negi Arvind S. , Luqman Suaib , Kaneez Fatima
Published: June 2016

Ethyl acetate extract ofSmilax korthalsiiA.D.C. leaves exhibited antiproliferative activity on leukaemia carcinoma K562, hepatic liver cancer cells WRL and colorectal carcinoma with IC50of 125.20, 46.10 and 160.00 μM respectively. Isolation of the bioactive ethyl acetate extract ofSmilax korthalsiiA.D.C. leaves gave eight compounds; 3β‐hydroxyspirost‐5‐ene (diosgenin),1, β‐sitosterol,2, lup‐5,11,20‐trien‐23‐ol,3, uneicos‐9‐enoic acid,4, ethylheptadecan‐17‐oic‐9‐enoate,5, cis‐octadec‐9‐enoic acid,6, hexadec9‐enoic acid,7and 11‐methyltridec‐12‐en‐1‐ol,8. The isolated compounds were tested against four human cancer cell lines: leukaemia carcinoma, K‐562; hepatic liver cancer cells, WRL; colorectal carcinoma, COLO; and breast carcinoma, MCF‐7 using the MTT assay. Diosgenin1exhibited significant antiproliferative activity against all four cell lines (IC50; K562=6.25, WRL=14.34, COLO=38.00, MCF‐7=12.40 μM), while compounds3, 6and7inhibited the growth of K‐562 at 20, 50 and 100 μM concentrations with IC50of 90.20, 75.92 and 50.72 μM respectively. Other isolated compounds also showed cytotoxic properties against K‐562, WRL and COLO, but showed low inhibition of MCF‐7.
Will (CH3)2COO Survive in Humid Conditions?
Authors: Lin Liang‐Chun , Takahashi Kaito
Published: June 2016

Criegee intermediates (CIs) are thought to be important oxidizing agents in the atmosphere; whereas in high humidity conditions, some CIs are quenched by water vapor, while some are immune from it. CIs’ reactivity toward water vapor is strongly dependent on the substituents of the CIs. It was reported previously that syn‐substituted CIs are less reactive toward water vapor than anti‐substituted ones, and this characteristic allows syn‐substituted CIs to survive in high humidity and react with other atmospheric trace gases, for example, SOx, NOx. In this paper, we calculated the rate coefficients of (CH3)2COO+(H2O)n,n=1,2 and compared them with those of syn‐CH3CHOO+(H2O)n,n=1,2 reported in our previous work. We discussed the substituent effect of CIs and the competition between SO2 and water vapor reaction at atmospheric conditions. In addition, we also discussed the tunneling correction with four different methods on these water mediated hydrogen transfer reactions. We calculated the rate coefficients with anharmonic correction for the partition function, with energetic values from our ratio extrapolation strategy, and with tunneling correction by small curvature approximation. At 298K the calculated bimolecular rate coefficients of (CH3)2COO+(H2O)2 and (CH3)2COO+H2O are 7.4×10−15 and 2.3×10−18 cm3sec−1, which are slow enough that (CH3)2COO can survive in high humidity condition, allowing it to possibly play an important role to oxidize SO2.
Nitrogen incorporation in saturated aliphatic C6–C8 hydrocarbons and ethanol in low‐pressure nitrogen plasma generated by a hollow cathode discharge ion source
Authors: Usmanov Dilshadbek T. , Chen Lee Chuin , Hiraoka Kenzo , Wada Hiroshi , Nonami Hiroshi , Yamabe Shinichi
Published: June 2016

Ion/molecule reactions of saturated hydrocarbons (n‐hexane, cyclohexane, n‐heptane, n‐octane and isooctane) in 28‐Torr N2 plasma generated by a hollow cathode discharge ion source were investigated using an Orbitrap mass spectrometer. It was found that the ions with [M+14]+ were observed as the major ions (M: sample molecule). The exact mass analysis revealed that the ions are nitrogenated molecules, [M+N]+ formed by the reactions of N3+ with M. The reaction, N3+ + M → [M+N]+ + N2, were examined by the density functional theory calculations. It was found that N3+ abstracts the H atom from hydrocarbon molecules leading to the formation of protonated imines in the forms of R′R″CNH2+ (i.e. C–H bond nitrogenation). This result is in accord with the fact that elimination of NH3 is the major channel for MS/MS of [M+N]+. That is, nitrogen is incorporated in the C–H bonds of saturated hydrocarbons. No nitrogenation was observed for benzene and acetone, which was ascribed to the formation of stable charge‐transfer complexes benzene⋅⋅⋅⋅N3+ and acetone⋅⋅⋅⋅N3+ revealed by density functional theory calculations. Copyright © 2016 John Wiley & Sons, Ltd.
Comment on: MALDI ionization mechanisms investigated by comparison of isomers of dihydroxybenzoic acid
Authors: Chen Jien‐Lian , Ni Chi‐Kung
Published: June 2016

Ionization mechanism of matrix‐assisted laser desorption/ionization was recently investigated by Kirmess et al. (J. Mass Spectrom. 2016, 51, 79). The authors compared the ion yields of dihydroxybenzoic acid isomers between experimental measurements and theoretical models and claimed that the predictions of chemical and physical dynamics model are in good agreement with experimental data, but the predictions of thermal model are not. Here, we show that wrong S1–S1 energy pooling rate constants and absorption cross sections were used in the aforementioned article. In addition, we suggest the authors to list the values of many parameters used in their calculations and describe how they obtained these values because these values are completely unknown.
Interdecadal changes in the links between Mediterranean evaporation and regional atmospheric dynamics during extended cold season
Authors: Zveryaev Igor I. , Hannachi Abdel B. A.
Published: June 2016

Monthly evaporation data for 1958–2010 from the Woods Hole Oceanographic Institution dataset are used to investigate interdecadal changes in interannual variability of Mediterranean evaporation and its links to regional climate. Analysis performed for the two climate periods characterized by the downward (1958–1978) and upward (1979–2010) trends of evaporation revealed significant season‐dependent interdecadal changes in its interannual variability. The largest changes in interannual variability have been revealed during autumn when the leading empirical orthogonal functions (EOFs) are characterized by a zonal dipole pattern (except in November 1979–2010). During winter and spring, the EOF‐1 and EOF‐2 are characterized, respectively, by a monopole pattern and a zonal dipole and are associated with the East Atlantic (EA) and the East Atlantic–West Russia (EAWR) teleconnections. It is shown that interdecadal changes in interannual variability of Mediterranean evaporation during cold season were determined by the EA transition from the strongly negative to more neutral phase that occurred in late 1970s. Seasonally dependent changes in the structure of the leading evaporation EOFs reflect changing roles of the EA and EAWR which impact near surface air temperature, specific humidity and wind.