bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of 2‐Alkylidene‐Substituted 1,3,4,5‐Tetramethylimidazolines and Their Reactivity Towards RhI Complexes and B(C6F5)3
Authors: Kronig Sabrina , Jones Peter G. , Tamm Matthias
Published: February 2013

In addition to the known 1,3,4,5‐tetramethyl‐2‐methyleneimidazoline (1a), which exhibits a highly polarized exocyclic C–C bond, a series of novel 2‐alkylidene‐substituted 1,3,4,5‐tetramethylimidazolines 1b–e were synthesized and characterized. The molecular structures of 1b, 1d, and 1e were determined by X‐ray diffraction analysis and revealed an increase in the polarization of the exocyclic C–C bond with increasing steric demand of the 2‐substituent. On the basis of their ylidic nature, 1a–e show enhanced basicity and reactivity towards Lewis acidic centers. Treatment of 1a and 1b with [{RhCl(cod)}2] or B(C6F5)3 afforded complexes of the type [(L)RhCl(cod)] (4a,b), [(L)RhCl(CO)2] (7a,b) (L = 1a,b) or classical Lewis acid/base adducts [(1a)B(C6F5)3] (8a) and [(1b)B(C6F5)3] (8b). In contrast, complexes [(L)RhCl(cod)] with 1c and 1d as ligands are not stable, and imidazolium dichlororhodate salts 6a and 6b were isolated instead. Rhodium–alkyl complexes 5a and 5b are assumed to be intermediates in this decomposition process, and 5a was characterized by X‐ray diffraction analysis. Furthermore, treatment of 1c and 1d with B(C6F5)3 did not afford classical Lewis adducts, and instead imidazolium hydridoborate salts 9a and 9b are formed by hydride abstraction. Surprisingly, we found that 1e does not react with [{RhCl(cod)}2] and forms an abnormal Lewis adduct 10 when treated with B(C6F5)3.
Brønsted Acid Catalyzed Highly Diastereoselective Michael‐Type Addition of Azlactones to Enones
Authors: Ávila Eloah P. , de Mello Amanda C. , Diniz Renata , Amarante Giovanni W.
Published: February 2013

A highly regio‐ and diastereoselective 1,4‐addition of azlactones to enones catalyzed by a Brønsted acid is described. The Michael adducts were prepared in moderate to good yields and with complete control of the relative stereochemistry. In addition, two consecutive stereogenic centers were created, one of which was a quaternary stereocenter. The method was successfully extended to the first highly diastereoselective desymmetrization of dibenzylidene acetone.
Building on the past, shaping the future: The environmental mutagenesis and genomics society
Authors: Wilson Thomas E. , DeMarini David M. , Dertinger Stephen D. , Engelward Bevin P. , Hanawalt Philip C. , MacGregor James T. , Smith‐Roe Stephanie L. , Witt Kristine L. , Yauk Carole L. , Ljungman Mats , Schwartz Jeffrey L. , Klein Catherine B.
Published: February 2013

In late 2012, the members of the Environmental Mutagen Society voted to change its name to the Environmental Mutagenesis and Genomics Society. Here, we describe the thought process that led to adoption of the new name, which both respects the rich history of a Society founded in 1969 and reflects the many advances in our understanding of the nature and breadth of gene‐environment interactions during the intervening 43 years. Environ. Mol. Mutagen. 54:153–157, 2013. © 2013 Wiley Periodicals, Inc.
Terrestrial gastropods (Helix spp) as sentinels of primary DNA damage for biomonitoring purposes: A validation study
Authors: Angeletti Dario , Sebbio Claudia , Carere Claudio , Cimmaruta Roberta , Nascetti Giuseppe , Pepe Gaetano , Mosesso Pasquale
Published: February 2013

We validated the alkaline comet assay in two species of land snail (Helix aspersa and Helix vermiculata) to test their suitability as sentinels for primary DNA damage in polluted environments. The study was conducted under the framework of a biomonitoring program for a power station in Central Italy that had recently been converted from oil to coal‐fired plant. After optimizing test conditions, the comet assay was used to measure the % Tail DNA induced by in vitro exposure of hemocytes to different concentrations of a reactive oxygen species (H2O2). The treatment induced significant increases in this parameter with a concentration effect, indicating the effectiveness of the assay in snail hemocytes. After evaluating possible differences between the two species, we sampled them in three field sites at different distances from the power station, and in two reference sites assumed to have low or no levels of pollution. No species differences emerged. Percent Tail DNA values in snails from the sites near the power station were higher than those from control sites. An inverse correlation emerged between % Tail DNA and distance from the power station, suggesting that the primary DNA damage decreased as distance increased away from the pollution source. Detection of a gradient of heavy metal concentration in snail tissues suggests that these pollutants are a potential cause of the observed pattern. The comet assay appears to be a suitable assay and Helix spp. populations suitable sentinels to detect the genotoxic impact of pollutants. Environ. Mol. Mutagen. 54:204–212, 2013. © 2013 Wiley Periodicals, Inc.
Utilization of palm pressed pericarp fiber: Pretreatment, optimization and characterization
Authors: Ling Hii Kiew , Pin Yeap Swee , Mashitah Mat Don
Published: February 2013

Four primary factors in controlling effectiveness of organosolvent pretreatment in lignin removal (%), cellulose retained (%), as well as hydrolysis (%) was done through a central composite design (CCD) coupled with response surface methodology (RSM). Statistically analysis predicted 54.49% of lignin removal, 86.40% of cellulose retained, and 90.67% of hydrolysis yield under numerically optimized process conditions (182.84 C, 0.61% solvent ratio, 0.69%w/w catalysts concentration, and 92.17 min reaction time). Almost reproducible results were successfully gained, suggesting feasible of design of experiment (DoE) in optimizing pressed pericarp fiber (PPF) pretreatment with nitric acid‐catalyzed ethanol solvent. Both the untreated and treated PPF were characterized by using scanning electron microscopy (SEM), X‐ray diffraction (XRD), and Fourier transformed infrared spectroscopy (FTIR). It was found that the treated PPF showed a distorted surface structure (SEM), amorphous and cellulose II pattern (XRD) and bonds shrinkage for several functional groups of lignin and hemicellulose while bands expanded for functional groups of cellulose (FTIR). © 2013 American Institute of Chemical Engineers Environ Prog, 33: 238–249, 2014
Reduction of [Fe(III)EDTA]− catalyzed by activated carbon modified with ammonia solution
Authors: Long Xiang‐Li , Yang Lin , Chou Xue‐wei , Li Cong , Yuan Wei‐kang
Published: February 2013

NO and SO2 can be removed simultaneously by [Fe(II)EDTA]2− solution. Activated carbon is used to catalyze the regeneration of [Fe(II)EDTA]2− to maintain the NO removal efficiency at a high level for a long time. In this article, ammonia solution has been tried to modify the coconut activated carbon to ameliorate its catalytic capability in the regeneration of [Fe(II)EDTA]2−. Experiments have been made in a batch stirred cell to investigate the effects of modification conditions, such as ammonia concentration, impregnation time, activation temperature, and activation time, on the catalytic performance of activated carbon. The experimental results suggest that the optimal modification condition be illustrated as follow: ammonia concentration 9.0 mol L−1, impregnation time 11 h, activation temperature 700°C, and activation time 4 h. After ammonia modification, the surface area of activated carbon decreases. But the total basicity of activated carbon is enhanced, which plays a vital role in improving the catalytic capability of activated carbon in the reduction of [Fe(III)EDTA]−. The activated carbon modified by ammonia solution can get a higher NO removal efficiency than the original activated carbon. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 99–106, 2014
A functional role of NMDA receptor in regulating the differentiation of oligodendrocyte precursor cells and remyelination
Authors: Li Cui , Xiao Lin , Liu Xiuyun , Yang Wenjing , Shen Weiran , Hu Chun , Yang Guang , He Cheng
Published: February 2013

Differentiation of oligodendrocyte precursor cells (OPCs) is the most important event for the myelination of central nervous system (CNS) axons during development and remyelination in demyelinating diseases, while the underlying molecular mechanisms remain largely unknown. Here we show that NMDA receptor (NMDAR) is a functional regulator of OPCs differentiation and remyelination. First, GluN1, GluN2A, and GluN2B subunits are expressed in oligodendrocyte lineage cells (OLs) in vitro and in vivo by immunostaining and Western blot analysis. Second, in a purified rat OPC culture system, NMDARs specially mediate OPCs differentiation by enhancing myelin proteins expression and the processes branching at the immature to mature oligodendrocyte transition analyzed by a serial of developmental stage‐specific antigens. Moreover, pharmacological NMDAR antagonists or specific knockdown of GluN1 by RNA interference in OPCs prevents the differentiation induced by NMDA. NMDA can activate the mammalian target of rapamycin (mTOR) signal in OPCs and the pro‐differentiation effect of NMDA is obstructed by the mTOR inhibitor rapamycin, suggesting NMDAR exerts its effect through mTOR‐dependent mechanism. Furthermore, NMDA increases numbers of myelin segments in DRG‐OPC cocultures. Finally, NMDAR specific antagonist MK801 delays remyelination in the cuprizone model examined by LFB‐PAS, immunofluorescence and electron microscopy. This effect appears to result from inhibiting OPCs differentiation as more NG2+ OPCs but less GST‐π+ mature oligodendrocytes are observed. Together, these results indicate that NMDAR plays a critical role in the regulation of OPCs differentiation in vitro and remyelination in cuprizone model which may provide potential target for the treatment of demyelination disease.
CX3CR1 deficiency induces an early protective inflammatory environment in ischemic mice
Authors: Fumagalli Stefano , Perego Carlo , Ortolano Fabrizio , De Simoni Maria‐Grazia
Published: February 2013

The studies on fractalkine and its unique receptor CX3CR1 in neurological disorders yielded contrasting results. We have explored the consequences of CX3CR1 deletion in ischemic (30′ MCAo) mice on: (1) brain infarct size; (2) microglia dynamism and morphology; (3) expression of markers of microglia/macrophages (M/M) activation and polarization. We observed smaller infarcts in cx3cr1−/− (26.42 ± 7.41 mm3, mean ± sd) compared to wild type (36.29 ± 11.57) and cx3cr1−/+ (34.49 ± 8.91) mice. We longitudinally analyzed microglia by in vivo two‐photon microscopy before, 1 and 24 h after transient ischemia. Microglia were stationary in both cx3cr1−/− and cx3cr1−/+ mice throughout the study. In cx3cr1−/− mice, they displayed a significantly higher number of ramifications >10 μm at baseline and at 24 h after ischemia compared to cx3cr1−/+ mice, indicating that CX3CR1 deficiency impaired the development of microglia hypertrophic/amoeboid morphology. At 24 h after ischemia, we performed post mortem quantitative immunohistochemistry for different M/M markers. In cx3cr1−/− immunoreactivity for CD11b (M/M activation) and for CD68 (associated with phagocytosis) were decreased, while that for CD45high (macrophage and leukocyte recruitment) was increased. In addition, immunoreactivity for Ym1 (M2 polarization) was enhanced, while that for iNOS (M1) was decreased. Our data show that in cx3cr1−/− mice protection from ischemia at early time points after injury is associated with a protective inflammatory milieu, characterized by the promotion of M2 polarization markers.
Quantifying Northern Hemisphere freshwater ice
Authors: Brooks Rheannon N. , Prowse Terry D. , O'Connell Ian J.
Published: February 2013

The areal extent and volume of peak freshwater (river and lake) ice are quantified across the Northern Hemisphere for the period 1957–2002. Quantification is conducted using a degree‐day ice growth model and ice growth coefficients defined for 14 ice‐specific hydroclimatic regions. The model is driven by ERA‐40 gridded daily air temperature data, and the Global Lakes and Wetlands Database is employed to spatially define rivers and lakes. Results indicate that the total area covered by freshwater ice, at peak thickness, north of the January 0°C isotherm (excluding the Greenland ice sheet) is 1.7 × 106 km2 and the total freshwater ice volume is 1.6 × 103 km3. This area is approximately equal to that of the Greenland ice sheet and the volume to snow on land (Northern Hemisphere). Such values now permit a more complete quantification of the cryosphere (evaluations already having been completed for other components, such as snow, glaciers, and sea ice) and provide a reference data set for assessing future climate‐related changes.
Further observations of a decreasing atmospheric CO2 uptake capacity in the Canada Basin (Arctic Ocean) due to sea ice loss
Authors: Else Brent G.T. , Galley R.J. , Lansard B. , Barber D.G. , Brown K. , Miller L.A. , Mucci A. , Papakyriakou T.N. , Tremblay J.‐É. , Rysgaard S.
Published: February 2013

Using data collected in 2009, we evaluated the potential for the southeastern Canada Basin (Arctic Ocean) to act as an atmospheric CO2 sink under the summertime ice‐free conditions expected in the near future. Beneath a heavily decayed ice cover, we found surprisingly high pCO2sw (~290–320 µatm), considering that surface water temperatures were low and the influence of ice melt was strong. A simple model simulating melt of the remaining ice and exposure of the surface water for 100 days revealed a weak capacity for atmospheric CO2 uptake (mean flux: −2.4 mmol m−2 d−1), due largely to warming of the shallow mixed layer. Our results confirm a previous finding that the Canada Basin is not a significant sink of atmospheric CO2 under summertime ice‐free conditions and that increased ventilation of the surface mixed layer due to sea ice loss is weakening the sink even further.
The birth and death of lakes on young landscapes
Authors: Englund Göran , Eriksson Håkan , Nilsson Mats B.
Published: February 2013

Ongoing land uplift caused by postglacial isostatic rebound creates strong landscape‐age gradients alongside the Gulf of Bothnia, northern Scandinavia. Lakes are continuously generated on this dynamic landscape as the uplift isolates bays from sea inundation. However, concomitant with this process older lakes are lost as the basins are filled with sediments, creating a continuum of lake ages on the landscape. We studied the lake size and depth distributions and lake densities, along an age gradient covering 0–4500 years. Map data on the density, area, and elevation of lakes were combined with field‐based measurements of maximum basin depth. We find that young lake populations are densely distributed and dominated by small and shallow lakes. Over time, small and shallow lakes are lost by complete sediment filling, resulting in lower lake density and a shift in size and depth distributions towards larger, deeper lakes. Since lake filling is a universal process, we propose that these findings can be generalized to other gradients in landscape age.
Detecting human influence on extreme temperatures in China
Authors: Wen Qiuzi Han , Zhang Xuebin , Xu Ying , Wang Bin
Published: February 2013

This study compares observed and model‐simulated spatiotemporal patterns of changes in Chinese extreme temperatures during 1961–2007 using an optimal detection method. Four extreme indices, namely annual maximum daily maximum (TXx) and daily minimum (TNx) temperatures and annual minimum daily maximum (TXn) and daily minimum (TNn) temperatures, are studied. Model simulations are conducted with the CanESM2, which include six 5‐member ensembles under different historical forcings, i.e., four individual external forcings (greenhouse gases, anthropogenic aerosol, land use change, and solar irradiance), combined effect of natural forcings (solar irradiance and volcanic activity), and combined effect of all external forcings (both natural and anthropogenic forcings). We find that anthropogenic influence is clearly detectable in extreme temperatures over China. Additionally, anthropogenic forcing can also be separated from natural forcing in two‐signal analyses. The influence of natural forcings cannot be detected in any analysis. Moreover, there are indications that the effects of greenhouse gases and/or land use change may be separated from other anthropogenic forcings in warm extremes TXx and TNx in joint two‐signal analyses. These results suggest that further investigations of roles of individual anthropogenic forcing are justified, particularly in studies of extremely warm temperatures over China.
AXIOMATIC FOUNDATIONS FOR COST‐EFFECTIVENESS ANALYSIS
Authors: Canning David
Published: February 2013

We show that individual utilities can be measured in units of healthy life years. Social preferences over these life metric utilities are assumed to satisfy the Pareto principle, anonymity, and invariance to a change in origin. These axioms generate a utilitarian social welfare function implying the use of cost‐effectiveness analysis in ordering health projects, based on maximizing the healthy years equivalents gained from a fixed health budget. For projects outside the health sector, our cost‐effectiveness axioms imply a form of cost–benefit analysis where both costs and benefits are measured in equivalent healthy life years. Copyright © 2013 John Wiley & Sons, Ltd.
Alantolactone inhibits growth of K562/adriamycin cells by downregulating Bcr/Abl and P‐glycoprotein expression
Authors: Yang Chunhui , Yang Jingbo , Sun Meiyan , Yan Jiangzhou , Meng Xiuxiang , Ma Tonghui
Published: February 2013

Alantolactone, a sesquiterpene lactone containing an α‐methylene‐γ‐lactone group, is the active component of Inula helenium (Compositae), a traditional Chinese medicinal herb. It has been reported that alantolactone has the capacity to inhibit tumor cell growth through induction of apoptosis. The purpose of this study was to assess the effects of alantolactone in the adriamycin (ADR)‐resistant human erythroleukemia cell line K562/ADR, and provide evidence that it might function as a potent therapeutic agent in chronic myelogenous leukemia (CML) patients with Bcr/Abl and the multidrug‐resistance phenotype. Our results showed that alantolactone significantly inhibited K562/ADR cell growth by downregulating Bcr/Abl and P‐glycoprotein expression. Alantolactone also induced apoptosis via modulation of protein levels of Bcl‐2 family members, caspase activation, poly ADP ribose polymerase cleavage, and cytochrome C release. We also observed that alantolactone induced cell‐cycle arrest in the G2/M phase, downregulated cyclin B1 and cyclin‐dependent protein kinase 1, and upregulated the cyclin‐dependent kinase inhibitor p21. Together, these results demonstrate that alantolactone may be a potent therapeutic agent against CML, and a potential Bcr/Abl inhibitor. © 2013 IUBMB Life., 65(5):435–444, 2013.
Alkylglycerol monooxygenase
Authors: Watschinger Katrin , Werner Ernst R.
Published: February 2013

Alkylglycerol monooxygenase (E.C. 1.14.16.5), also called glyceryl ether monooxygenase, is a tetrahydrobiopterin‐dependent enzyme. It is the only enzyme known to cleave the ether bond of alkylglycerols and lyso‐alkylglycerol phospholipids, including lyso‐platelet activating factor. Although it has been first described already in 1964, it was not possible so far to purify the protein. It took until 2010 to assign a sequence to this labile integral membrane enzyme by bioinformatic selection of candidate genes, recombinant expression of these, and sensitive monitoring of the enzymatic activity by a fluorescence‐based assay. The sequence shows no significant similarity with the other known tetrahydrobiopterin‐dependent enzymes but contains the fatty acid hydroxylase protein motif signature. Proteins containing this signature are all labile and catalyze reactions similar to the alkylglycerol monooxygenase reaction. They are thought to use a di‐iron centre for catalysis. Site directed mutagenesis of alkylglycerol monooxygenase defined a region of the active site and a conserved glutamate residue important for tetrahydrobiopterin interaction. Current research now focuses on defining a physiological role of this enzyme which occurs not only in mammals but also in commonly used model organisms such as zebrafish and the nematode Caenorhabditis elegans. © 2013 IUBMB Life 65(4):366–372, 2013.
Mechanisms of tryptophan and tyrosine hydroxylase
Authors: Roberts Kenneth M. , Fitzpatrick Paul F.
Published: February 2013

The aromatic amino acid hydroxylases tryptophan hydroxylase and tyrosine hydroxylase are responsible for the initial steps in the formation of serotonin and the catecholamine neurotransmitters, respectively. Both enzymes are nonheme iron‐dependent monooxygenases that catalyze the insertion of one atom of molecular oxygen onto the aromatic ring of their amino acid substrates, using a tetrahydropterin as a two electron donor to reduce the second oxygen atom to water. This review discusses the current understanding of the catalytic mechanism of these two enzymes. The reaction occurs as two sequential half reactions: a reaction between the active site iron, oxygen, and the tetrahydropterin to form a reactive FeIVO intermediate and hydroxylation of the amino acid by the FeIVO. The mechanism of formation of the FeIVO is unclear; however, considerable evidence suggests the formation of an FeII‐peroxypterin intermediate. The amino acid is hydroxylated by the FeIVO intermediate in an electrophilic aromatic substitution mechanism. © 2013 IUBMB Life 65(4):350–357, 2013.
Src kinases mediate VEGFR2 transactivation by the osteostatin domain of PTHrP to modulate osteoblastic function
Authors: García‐Martín Adela , Acitores Alicia , Maycas Marta , Villanueva‐Peñacarrillo María L. , Esbrit Pedro
Published: February 2013

Parathyroid hormone‐related protein (PTHrP) stimulates osteoblastic function through its N‐ and C‐terminal domains. Since the osteogenic action of the latter domain appears to depend at least in part on its interaction with the vascular endothelial growth factor (VEGF) system, we aimed to explore the putative mechanism underlying this interaction in osteoblasts. Using native conditions for protein extraction and immunoblotting, we found that both PTHrP (107–139) and the shorter PTHrP (107–111) peptide (known as osteostatin), at 100 nM, promoted the appearance of a VEGF receptor (VEGFR) 2 protein band of apparent Mr. wt. 230 kDa, which likely represents its activation by dimer formation, in mouse osteoblastic MC3T3‐E1 cells. Moreover, osteostatin (100 nM) maximally increased VEGFR2 phosphorylation at Tyr‐1059 within 5–10 min in both MC3T3‐E1 and rat osteoblastic osteosarcoma UMR‐106 cells. This phosphorylation elicited by osteostatin appears to be VEGF‐independent, but prevented by the VEGFR2 activation inhibitor SU1498 and also by the Src kinase inhibitors SU6656 and PP1. Furthermore, osteostatin induced phosphorylation of Src, extracellular signal‐regulated kinase (ERK) and Akt with a similar time course to that observed for VEGFR2 activation in these osteoblastic cells. This osteostatin‐dependent induction of ERK and Akt activation was abrogated by SU6656. Up‐regulation of VEGF and osteoprotegerin gene expression as well as the pro‐survival effect induced by osteostatin treatment were all prevented by both SU1498 and SU6656 in these osteoblastic cells. Collectively, these findings demonstrate that the osteostatin domain of C‐terminal PTHrP phosphorylates VEGFR2 through Src activation, which represents a mechanism for modulating osteoblastic function. J. Cell. Biochem. 114: 1404–1413, 2013. © 2012 Wiley Periodicals, Inc.
Structure and function of mycobacterium glycopeptidolipids from comparative genomics perspective
Authors: Pang Lei , Tian Xuelian , Pan Weihua , Xie Jianping
Published: February 2013

Glycopeptidolipids (GPLs) attached to the outer surface of the greasy cell envelope, are a class of important glycolipids synthesized by several non‐tuberculosis mycobacteria. The deletion or structure change of GPLs confers several phenotypical changes including colony morphology, hydrophobicity, aggregation, sliding motility, and biofilm formation. In addition, GPLs, particular serovar specific GPLs, are important immunomodulators. This review aims to summarize the advance on the structure, function and biosynthesis of mycobacterium GPLs. J. Cell. Biochem. 114: 1705–1713, 2013. © 2013 Wiley Periodicals, Inc.
Specific route mapping visualized with GFP of single‐file streaming contralateral and systemic metastasis of Lewis lung carcinoma cells beginning within hours of orthotopic implantion
Authors: Rashidi Babak , Moossa Abdool R. , Hoffman Robert M.
Published: February 2013

In this study, we visualized the origin of Lewis lung carcinoma metastasis after transducing tumor cells with green fluorescent protein (GFP) and transplanting them orthotopically in the middle lobe of the right lung of nude mice. Metastasis was visualized in live tissue at single cell resolution by GFP‐expression as early as 18 h post‐tumor transplant. At this time, single‐file streaming lung carcinoma cells already had invaded inferiorly via a tubular lymphatic structure crossing the lower lobes of the lung to the ipsilateral diaphragmatic surface. By post‐implantation day 2, the ipsilateral lower lobes of the lung were involved with metastatic cells. By post‐implantation day 3, the ipsilateral lower lobes of the lung and the ipsilateral diaphragmatic surface were highly involved with streaming metastatic cells trafficking in single file. By day 4 post‐implantation, cancer cells invaded across the diaphragm to the contralateral diaphragmatic surface. Metastatic cells then invaded superiorly through a lymphatic vessel to involve the contralateral mediastinal lymph nodes. In this model of lung cancer, the origin of metastasis was an inferior invasion from the implanted tumor via a lymphatic duct to the ipsilateral diaphragmatic surface. The cancer cells from this site invaded on the surface of the diaphragm to the contralateral diaphragmatic surface and proceeded superiorly through a lymphatic duct to contralateral lymph nodes. Other organs such as the kidneys and the adrenal glands later became involved with metastasis with the contralateral mediastinal lymph nodes as the source. The use of GFP and the highly metastatic orthotopic lung cancer model allowed the visualization of the origin of metastasis at the single‐cell level and demonstrated the critical role of lymphatic ducts and the diaphragmatic surface as the path to the contralateral side. J. Cell. Biochem. 114: 1738–1743, 2013. © 2013 Wiley Periodicals, Inc.
Rapamycin inhibits BMP‐7‐induced osteogenic and lipogenic marker expressions in fetal rat calvarial cells
Authors: Yeh Lee‐Chuan C. , Ma Xiuye , Ford Jeffery J. , Adamo Martin L. , Lee John C.
Published: February 2013

Bone morphogenetic proteins (BMPs) promote osteoblast differentiation and bone formation in vitro and in vivo. BMPs canonically signal through Smad transcription factors, but BMPs may activate signaling pathways traditionally stimulated by growth factor tyrosine kinase receptors. Of these, the mTOR pathway has received considerable attention because BMPs activate P70S6K, a downstream effector of mTOR, suggesting that BMP‐induced osteogenesis is mediated by mTOR activation. However, contradictory effects of the mTOR inhibitor rapamycin (RAPA) on bone formation have been reported. Since bone formation is thought to be inversely related to lipid accumulation and mTOR is also important for lipid synthesis, we postulated that BMP‐7 may stimulate lipogenic enzyme expression in a RAPA‐sensitive mechanism. To test this hypothesis, we determined the effects of RAPA on BMP‐7‐stimulated expression of osteogenic and lipogenic markers in cultured fetal rat calvarial cells. Our study showed that BMP‐7 promoted the expression of osteogenic and lipogenic markers. The effect of BMP‐7 on osteogenic markers was greater in magnitude than on lipogenic markers and was temporally more sustained. RAPA inhibited basal and BMP‐7‐stimulated osteogenic and lipogenic marker expression and bone nodule mineralization. The acetyl CoA carboxylase inhibitor TOFA stimulated the expression of osteoblast differentiation markers, whereas palmitate suppressed their expression. We speculate that the BMP‐7‐stimulated adipogenesis is part of the normal anabolic response to BMPs, but that inappropriate activation of the lipid biosynthetic pathway by mTOR could have deleterious effects on bone formation and could explain paradoxical effects of RAPA to promote bone formation. J. Cell. Biochem. 114: 1760–1771, 2013. © 2013 Wiley Periodicals, Inc.
Functional studies of MP62 during male chromatin decondensation in sea urchins
Authors: Iribarren Claudio , Hermosilla Viviana , Morin Violeta , Puchi Marcia
Published: February 2013

In amphibians, sperm histone transition post‐fertilization during male pronucleus formation is commanded by histone chaperone Nucleoplasmin (NPM). Here, we report the first studies to analyze the participation of a Nucleoplasmin‐like protein on male chromatin remodeling in sea urchins. In this report, we present the molecular characterization of a nucleoplasmin‐like protein that is present in non fertilized eggs and early zygotes in sea urchin specie Tetrapygus niger. This protein, named MP62 can interact with sperm histones in vitro. By male chromatin decondensation assays and immunodepletion experiments in vitro, we have demonstrated that this protein is responsible for sperm nucleosome disorganization. Furthermore, as amphibian nucleoplasmin MP62 is phosphorylated in vivo immediately post‐fertilization and this phosphorylation is dependent on CDK‐cyclin activities found after fertilization. As we shown, olomoucine and roscovitine inhibits male nucleosome decondensation, sperm histone replacement in vitro and MP62 phosphorylation in vivo. This is the first report of a nucleoplasmin‐like activity in sea urchins participating during male pronucleus formation post‐fecundation. J. Cell. Biochem. 114: 1779–1788, 2013. © 2013 Wiley Periodicals, Inc.
IS IT BOTH WHAT YOU KNOW AND WHO YOU KNOW? HUMAN CAPITAL, SOCIAL CAPITAL AND ENTREPRENEURIAL SUCCESS
Authors: Kolstad Ivar , Wiig Arne
Published: February 2013

This paper analyses the importance of human and social capital for entrepreneurial success, using survey data of 459 urban entrepreneurs in Luanda, Angola. The paper offers four main findings: (i) an added year of schooling significantly increases entrepreneurial profits; (ii) different family background variables are associated with the educational attainment of men and women, indicating that educational attainment is gendered; (iii) profits are substantially lower for entrepreneurs suffering from chronic illness; and (iv) entrepreneurs who know a local police officer have higher profits, suggesting that specific forms of networks are related to entrepreneurial success. Copyright © 2013 John Wiley & Sons, Ltd.
Physical Properties, Crystallization, and Thermal/Hydrolytic Degradation of Poly(L‐lactide)/Nano/Micro‐Diamond Composites
Authors: Tsuji Hideto , Aratani Toshiyuki , Takikawa Hirofumi
Published: February 2013

The effects of incorporated nano/micro‐diamond (NMD) on the physical properties, crystallization, thermal/hydrolytic degradation of poly(L‐lactic acid) (PLLA) were investigated for a wide NMD concentration range of 0–10 wt.‐%. Incorporated NMD increased the tensile modulus and strength of PLLA films but decreased the elongation at break of PLLA films. Incorporated NMD accelerated the crystallization of PLLA during heating and cooling and increased the absolute crystallization enthalpy of PLLA films (except for an NMD concentration of 10 wt.‐% during cooling) but did not alter the crystallization mechanism. Incorporated NMD increased and decreased the thermal stability of PLLA films for NMD concentrations of 1–5 and 10 wt.‐%, respectively, and increased the hydrolytic degradation resistance of PLLA films.

magnified image
Association of isolated short fetal femur with intrauterine growth restriction
Authors: Vermeer N. , Bekker M. N.
Published: February 2013

Objectives

To analyze the outcomes of fetuses referred because of short femur length.

Methods

This was a retrospective study of all singleton pregnancies referred to a tertiary care referral hospital with a femur length below the 5th percentile. All ultrasound scan reports, including Doppler, fetal karyotyping, pregnancy outcome and neonatal data were analyzed.

Results

In 112 patients, 87 (78%) had an isolated short femur and 25 (22%) had a non‐isolated short femur. The non‐isolated cases consisted of chromosomal disorders (n = 6), skeletal abnormalities (n = 6), multiple abnormalities (n = 12) and 1 genetic disorder. In the isolated group 37 cases (43%) were intrauterine growth restricted (positive likelihood ratio 1.20, negative likelihood ratio 0.45). In 33 cases the short femur was unexplained and 17 referrals were considered false‐positive. The growth restricted group had significant more abnormal Doppler measurements (p = 0.01), caesarean deliveries (p = 0.043) and admissions to the neonatal intensive care unit (p = 0.001).

Conclusion

An isolated short femur is associated with intrauterine growth restriction and adverse pregnancy outcome. © 2013 John Wiley & Sons, Ltd.
First principles view on chemical compound space: Gaining rigorous atomistic control of molecular properties
Authors: von Lilienfeld O. Anatole
Published: February 2013

A well‐defined notion of chemical compound space (CCS) is essential for gaining rigorous control of properties through variation of elemental composition and atomic configurations. Here, we give an introduction to an atomistic first principles perspective on CCS. First, CCS is discussed in terms of variational nuclear charges in the context of conceptual density functional and molecular grand‐canonical ensemble theory. Thereafter, we revisit the notion of compound pairs, related to each other via “alchemical” interpolations involving fractional nuclear charges in the electronic Hamiltonian. We address Taylor expansions in CCS, property nonlinearity, improved predictions using reference compound pairs, and the ounce‐of‐gold prize challenge to linearize CCS. Finally, we turn to machine learning of analytical structure property relationships in CCS. These relationships correspond to inferred, rather than derived through variational principle, solutions of the electronic Schrödinger equation. © 2013 Wiley Periodicals, Inc.
Probing actinide electronic structure through pu cluster calculations
Authors: Ryzhkov Mickhail V. , Mirmelstein Alexei , Yu Sung‐Woo , Chung Brandon W. , Tobin James G.
Published: February 2013

Calculations of the electronic structure of clusters of plutonium have been performed, within the framework of the relativistic discrete‐variational method. These theoretical results and those calculated earlier for related systems have been compared to spectroscopic data produced in the experimental investigations of bulk systems, including photoelectron spectroscopy. Observation of the changes in the Pu electronic structure as a function of size provides powerful insight for aspects of bulk Pu electronic structure. © 2013 Wiley Periodicals, Inc.
Graphene‐Bonded and ‐Encapsulated Si Nanoparticles for Lithium Ion Battery Anodes
Authors: Wen Yang , Zhu Yujie , Langrock Alex , Manivannan Ayyakkannu , Ehrman Sheryl H. , Wang Chunsheng
Published: February 2013

Silicon (Si) has been considered a very promising anode material for lithium ion batteries due to its high theoretical capacity. However, high‐capacity Si nanoparticles usually suffer from low electronic conductivity, large volume change, and severe aggregation problems during lithiation and delithiation. In this paper, a unique nanostructured anode with Si nanoparticles bonded and wrapped by graphene is synthesized by a one‐step aerosol spraying of surface‐modified Si nanoparticles and graphene oxide suspension. The functional groups on the surface of Si nanoparticles (50–100 nm) not only react with graphene oxide and bind Si nanoparticles to the graphene oxide shell, but also prevent Si nanoparticles from aggregation, thus contributing to a uniform Si suspension. A homogeneous graphene‐encapsulated Si nanoparticle morphology forms during the aerosol spraying process. The open‐ended graphene shell with defects allows fast electrochemical lithiation/delithiation, and the void space inside the graphene shell accompanied by its strong mechanical strength can effectively accommodate the volume expansion of Si upon lithiation. The graphene shell provides good electronic conductivity for Si nanoparticles and prevents them from aggregating during charge/discharge cycles. The functionalized Si encapsulated by graphene sample exhibits a capacity of 2250 mAh g−1 (based on the total mass of graphene and Si) at 0.1C and 1000 mAh g−1 at 10C, and retains 85% of its initial capacity even after 120 charge/discharge cycles. The exceptional performance of graphene‐encapsulated Si anodes combined with the scalable and one‐step aerosol synthesis technique makes this material very promising for lithium ion batteries.
Skills and abilities for working in a global software development team: a competence model
Authors: Saldaña‐Ramos Javier , Sanz‐Esteban Ana , García Javier , Amescua Antonio
Published: February 2013

Nowadays, it is common to develop software development projects collaboratively among team members or organizations in different geographical locations. These teams, known as global software development (GSD) teams, allow organizations to save costs as well as have available highly qualified personnel. This kind of team is different from traditional teams, so it is necessary for team members to develop other essential competences to work efficiently in a global context. Unfortunately, there is no well‐defined competence model that allows organizations to assess personnel competences and establish the relevant training program that allows them to work efficiently in such teams. This work defines and implements, in four GSD teams, a competence model specifically designed to address challenges that people face when they work in a GSD team. This competence model has been defined considering tasks a GSD team have to carry out, bodies of knowledge, and existing competence models for the software engineering profiles and the authors' experience working in such teams. As a result of the implementation process, it was confirmed that the competence model is a key factor for human capital improvement. When personnel have these competences, team and individual efficiency and product quality increase, and delays in delivering products decrease. Copyright © 2013 John Wiley & Sons, Ltd.
Interpreting Student Views of Learning Experiences in a Contextualized Science Discourse in Kenya
Authors: Nashon Samson Madera , Anderson David
Published: February 2013

Despite the centrality of the informal manufacturing sector (Jua Kali) to the Kenyan society and its richness in scientific phenomena, there is no strong link between activities in the Jua Kali and school science. And, although there has been an ongoing public discourse in Kenya to industrialize, this hope is unlikely without connecting classroom science to the real world of the Jua Kali. In view of this concern, an interpretive case study was framed to investigate Kenyan high school students' views of contextualized science learning in culturally relevant real‐world science curriculum. This article reports the analysis of Kenyan students' views of contextualized science learning and school science curriculum and instruction elicited through an interpretive case study approach employing interview methods. The analysis of interview data reveals that the participating students interviewed expressed views that: (1) acknowledged the richness of Jua Kali in scientific phenomena and embedded science; (2) indicated existence of a lack of meaningfulness and relevance in existing science curriculum and instruction model; (3) revealed experience of resonance of group and real life learning strategies modeled in the curriculum unit with their preferred learning modes; and (4) revealed their metacognitive assessment of the traditionally used and the new contextualized science modeled learning strategies. Thus, this article offers insight about the Kenyan students on their journey through the experience of contextualized science learning. © 2013 Wiley Periodicals, Inc. J Res Sci Teach 50: 381‐407, 2013
Detection and attribution of anthropogenic climate change impacts
Authors: Rosenzweig Cynthia , Neofotis Peter
Published: February 2013

Human‐influenced climate change is an observed phenomenon affecting physical and biological systems across the globe. The majority of observed impacts are related to temperature changes and are located in the northern high‐ and mid‐latitudes. However, new evidence is emerging that demonstrates that impacts are related to precipitation changes as well as temperature, and that climate change is impacting systems and sectors beyond the Northern Hemisphere. In this paper, we highlight some of this new evidence—focusing on regions and sectors that the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) noted as under‐represented—in the context of observed climate change impacts, direct and indirect drivers of change (including carbon dioxide itself), and methods of detection. We also present methods and studies attributing observed impacts to anthropogenic forcing. We argue that the expansion of methods of detection (in terms of a broader array of climate variables and data sources, inclusion of the major modes of climate variability, and incorporation of other drivers of change) is key to discerning the climate sensitivities of sectors and systems in regions where the impacts of climate change currently remain elusive. Attributing such changes to human forcing of the climate system, where possible, is important for development of effective mitigation and adaptation. Current challenges in documenting adaptation and the role of indigenous knowledge in detection and attribution are described. WIREs Clim Change 2013, 4:121–150. doi: 10.1002/wcc.209

This article is categorized under:

Assessing Impacts of Climate Change > Observed Impacts of Climate Change
Controls on topographic dependence and temporal instability in catchment‐scale soil moisture patterns
Authors: Coleman Michael L. , Niemann Jeffrey D.
Published: February 2013

Key Points

Type of topographic dependence mainly depends on soil & vegetation properties

Temporal instability increases if lateral flow & radiative ET are balanced

Soil & vegetation properties mainly determine if the dominant process changes
Holography for general gauge mediation
Authors: McGarrie Moritz
Published: February 2013

Abstract

We construct a holographic model of spontaneous supersymmetry breaking in analogy to AdS/QCD models. Integrating out the bulk theory one obtains an entirely four dimensional effective action that encodes spontaneous supersymmetry breaking effects, coupled to external sources. Using only this four dimensional action it is possible to compute soft masses, scattering cross sections and determine the form factors of vector mesons. This construction lends itself to a more natural comparison with operator product expansions.
Long-lived higgsinos as probes of gravitino dark matter at the LHC
Authors: Bobrovskyi S. , Hajer J. , Rydbeck S.
Published: February 2013

Abstract

We investigate the LHC sensitivity to supersymmetric models with light higgsinos, small R-parity breaking and gravitino dark matter. The limits on decaying gravitino dark matter from gamma-ray searches with the Fermi-LAT put a lower bound on the higgsino-like neutralino NLSP decay length, giving rise to a displaced-vertex collider signature. Using publicly available tools for simulation of signal, background and detector response, we find that higgsinos with masses of 100 – 400 GeV and R-parity violation ofζ~ 10−8– 10−9can show up in the 8 TeV LHC data with 10 – 30 fb−1of integrated luminosity. We demonstrate that in the case of a signal, the higgsino mass can be determined by reconstruction of the dimuon mass edge.
Inter‐annual variability of seed rain and seedling establishment of two woody Mediterranean species under field‐induced drought and warming
Authors: del Cacho Montse , Estiarte Marc , Peñuelas Josep , Lloret Francisco
Published: February 2013

We aimed to assess the impact of warmer and drier climate change conditions on the seed rain and seedling establishment of Globularia alypum L. and Erica multiflora L., two dominant species in Western coastal Mediterranean shrublands. We performed a non‐intrusive field experiment in which we increased the night‐time temperatures and excluded spring and autumn rainfall. We monitored the seed rain over 5 years and the seedling recruitment over 9 years on these experimental plots. Seed rain of E. multiflora was enhanced by warming treatment in relation to control, and higher annual rainfall, while seed rain of G. alypum was increased by drought treatment in relation to control, dry years and higher minimum annual temperature. Annual rainfall enhanced the seedling emergence of both species, which also positively correlated with annual mean temperatures. Drought treatment significantly decreased seedling emergence for both species, which was higher in open areas than below vegetation cover. The seedling survival of both species diminished at closer distances to competing neighbours, and in G. alypum seedling survival was higher with lower annual mean temperatures and higher annual rainfall, but also in drought treatment, which have experienced vegetation cover decline. The study confirms that the increasing aridity in Mediterranean ecosystems would constrain the early stages of development in typical co‐occurring shrubs. However, there are contrasting responses to climatic conditions between species recruitment, which might favour changes in vegetation through modification of species relative abundance.
Effects of increasing nutrient supply and omnivorous feeding on the size spectrum slope: a size‐based nutrient‐phytoplankton‐zooplankton model
Authors: Ho Pei‐Chi , Chang Chun‐Wei , Hsieh Chih Hao , Shiah Fuh‐Kwo , Miki Takeshi
Published: February 2013

Size spectrum slope has been considered as an indicator for system productivity and size‐dependent trophic interactions in plankton communities. We investigated the effect of new nutrient flux (Nin) and feeding breadth of zooplankton (σ2) on spectral slopes of the plankton community using a size‐structured nutrient‐phytoplankton‐zooplankton model. We studied two types of plankton systems (1) at a steady state and (2) with fluctuating plankton populations. For the steady state systems, the spectral slopes increased with Nin and σ2. In contrast, for the systems in fluctuation, spectral slopes constructed from long‐term average plankton populations decreased with increasing Nin and σ2. In addition to spectral slopes constructed from long‐term average population densities, we investigated slope variability in systems with fluctuating plankton populations. The variability of spectral slopes was found to increase with Nin and σ2, indicating that spectral slope variation is large in a eutrophic system or when zooplankton feed on a wide size range of prey. Empirically, because Nin is difficult to measure, nutrient concentration is investigated instead. Our model predicts that the spectral slope is positively correlated with nutrient concentration due to the accumulated mesozooplankton biomass, which was confirmed by our study in plankton community in a subtropical reservoir in Taiwan.