bluuebunny/crossref_metadata_2025 huggingface dataset:
Tumor necrosis factor‐α treatment of HepG2 cells mobilizes a cytoplasmic pool of ERp57/1,25D3‐MARRS to the nucleus
Authors: Grindel Brian J. , Rohe Benjamin , Safford Susan E. , Bennett Joseph J. , Farach‐Carson Mary C.
Published: May 2011

ERp57/PDIA3/1,25‐MARRS has diverse functions and multiple cellular locations in various cell types. While classically described as an endoplasmic reticulum (ER) resident protein, ERp57 has a nuclear location sequence (NLS) and can enter the nucleus from the cytosol to alter transcription of target genes. Dysregulation and variable expression of ERp57 is associated with a variety of cancers including hepatocellular carcinoma (HCC). We investigated the dynamic mobility of ERp57 in an HCC cell line, HepG2, to better understand the movement and function of the non‐ER resident pool of ERp57. Subcellular fractionation indicated ERp57 is highly expressed in the ER with a smaller cytoplasmic pool in HepG2 cells. Utilizing an ERp57 green fluorescent protein fusion construct created with and without a secretory signal sequence, we found that cytoplasmic ERp57 translocated to the nucleus within 15 min after tumor necrosis factor‐α (TNF‐α) treatment. Protein kinase C activators including 1,25‐dihydroxyvitamin D3 and phorbol myristate acetate did not trigger nuclear translocation of ERp57, indicating translocation is PKC independent. To determine if an interaction between the rel homology binding domain in ERp57 and the nuclear factor‐κB subunit, p65, occurred after TNF‐α treatment and could account for nuclear movement, co‐immunoprecipitation was performed under control and conditions that stabilized labile disulfide bonds. No support for a functional interaction between p65 and ERp57 after TNF‐α treatment was found in either case. Immunostaining for both ERp57‐GFP and p65 after TNF‐α treatment indicated that nuclear translocation of these two proteins occurs independently in HepG2 cells. J. Cell. Biochem. 112: 2606–2615, 2011. © 2011 Wiley‐Liss, Inc.
Effects of nonylphenol on the production of progesterone on the rats granulosa cells
Authors: Yu Po‐Ling , Lin Han‐Wei , Wang Shyi‐Wu , Wang Paulus S.
Published: May 2011

We investigated the effects of nonylphenol (NP) on release of progesterone (PG) by granulosa cells (GCs) of rats in vitro and in vivo. First, GCs were treated with different doses of NP for 2–24 h alone or with human chorionic gonadotropin (hCG). Maximal PG secretion at 8 h noted, GCs were treated for 2 h with hCG, 8‐bromo‐adenosine 3′:5′‐cyclic monophosphate (8‐Br‐cAMP), forskolin, A23187, nifedipine, and pregnelonone to evaluate the NP effects on PG steroidogenesis. Results indicated that all of chemicals except nifedipine stimulated the PG release compared to vehicle, but the stimulatory effects could not be enhanced by different doses of NP. Second, GCs were isolated to react with hCG, 8‐Br‐cAMP and PD98059 after the immature female rats gavaged with different doses of NP (ONP) for 7 days. PG released significantly when rats treated with oral NP 100 compared to 0 µg/kg/day. Third, GCs collected from the female offspring of mother rats which gavaged with NP 100 µg/kg/day for 21 days during pregnancy (MONP) reacted with different doses of chemicals. The results showed that PG release in the presence of chemicals was significantly higher in ONP and MONP groups; however, this stimulation was not noted by dose‐dependent. The plasma concentration of PG was higher in ONP (100 µg/kg/day) and the offspring of MONP groups. The steroidogenic acute regulatory (StAR) protein expressed higher in all three groups by Western blotting. This study results indicated that low dose of NP stimulated PG release in rat GCs by activation of StAR protein. J. Cell. Biochem. 112: 2627–2636, 2011. © 2011 Wiley‐Liss, Inc.
C‐kit mutations and PKC crosstalks: PKC translocates to nucleous only in cells HMC560,816
Authors: Tobío Araceli , Alfonso Amparo , Botana Luis M.
Published: May 2011

The human mast cell lines HMC‐1560 and HMC‐1560,816 were used to study histamine release, Ca2+ signaling and protein kinase C (PKC) localization and expression, with phorbol 12‐myristate 13‐acetate (PMA). Both sublines carry activating mutations in the proto‐oncogene of c‐kit that cause autophosphorylation and permanent c‐kit tyrosine kinase activation. Both have the Gly‐560 → Val mutation but only the second carries the Asp‐816 → Val mutation. In this study, it was observed that the stimulation of PKC has different effects in HMC‐1560 and HMC‐1560,816 and this would be related to the difference in activating mutations in both mast cell lines. PKC activation increases ionomycin‐induced histamine release in HMC‐1560. This article demonstrates an opposite histamine response in HMC‐1560,816 cells, even though classical PKCs are the family of isozymes responsible for this effect in both cellular lines. Furthermore, it can be observed that upon cell stimulation with PMA, primarily cytosolic PKC translocates to the nucleous in HMC‐1560,816 cells, but not in HMC‐1560 cell line. J. Cell. Biochem. 112: 2637–2651, 2011. © 2011 Wiley‐Liss, Inc.
Computer simulation of trifluoromethane properties with ab initio force field
Authors: Chung Yi‐Hsing , Li Arvin Huang‐Te , Chao Sheng D.
Published: May 2011

Intermolecular interaction potentials of the trifluoromethane dimer in 15 orientations have been calculated using the Hartree‐Fock (HF) self‐consistent theory and the second‐order Møller‐Plesset (MP2) perturbation theory. Single point energies at important geometries were also calibrated by the coupled cluster with single and double and perturbative triple excitation [CCSD(T)] calculations. We have employed Pople's medium size basis sets [up to 6‐311++G(3df,3pd)] and Dunning's correlation consistent basis sets (up to aug‐cc‐pVQZ). Basis set limit potential values were obtained through well‐studied extrapolation methods. The calculated MP2 potential data were employed to parameterize a 5‐site force field for molecular simulations. We performed molecular dynamics simulations using the constructed ab initio force field and compared the simulation results with experiments. Quantitative agreements for the atom‐wise radial distribution functions and the self‐diffusion coefficients over a wide range of experimental conditions can be obtained, thus validating the ab initio force field without using experimental data a priori. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
A dissected ring current model for assessing magnetic aromaticity: A general approach for both organic and inorganic rings
Authors: Foroutan‐Nejad Cina , Shahbazian Shant , Feixas Ferran , Rashidi‐Ranjbar Parviz , Solà Miquel
Published: May 2011

A model based on classical electrodynamics is used to measure the strength of ring currents of different molecular orbitals, i.e., σ‐ and π‐orbitals, and characteristics of ring current loops, i.e., ring current radii and height of current loops above/below the ring planes, among a number of organic as well as inorganic molecules. For the π‐current, the present model represents an improvement of previous approaches to determine ring current intensity. It is proven that the present model is more precise than previous models as they could not explain presence of the minimum in the plot of NICSπzzversus distance close to the ring plane. Variations in the charge of molecules and the types of constituent atoms of each species affect the ring current radii of both σ‐ and π‐current loops as well as the height of π‐current loops above/below the ring plane. It is suggested that variation in the distribution of the one‐electron density in different systems is the main source of differences of the ring current characteristics. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Application of a ligand‐based theoretical approach to derive conversion paths and ligand conformations in CYP11B2‐mediated aldosterone formation
Authors: Roumen Luc , Van Hoof Bram , Pieterse Koen , Hilbers Peter A.J. , Custers Erica M.G. , Plate Ralf , De Gooyer Marcel , Beugels Ilona P.E. , Emmen Judith M.A. , Leysen Dirk , Smits Jos F.M. , Ottenheijm Harry C.J. , Hermans J.J. Rob
Published: May 2011

The biosynthesis of the mineralocorticoid hormone aldosterone involves a multistep hydroxylation of 11‐deoxycorticosterone at the 11‐ and 18‐positions, resulting in the formation of corticosterone and 18‐hydroxycorticosterone, the final precursor of aldosterone. Two members of the cytochrome P450 11B family, CYP11B1 and CYP11B2, are known to catalyze these 11‐ and 18‐hydroxylations, however, only CYP11B2 can oxidize 18‐hydroxycorticosterone to aldosterone. It is unknown what sequence of hydroxylations leads to the formation of 18‐hydroxycorticosterone. In this study we have investigated which of the possible conversion paths towards formation of 18‐hydroxycorticosterone and aldosterone are most likely from the ligand perspective. Therefore, we combined quantum mechanical investigations on the steroid conformations of 11‐deoxycorticosterone and its ensuing reaction intermediates with Fukui indices calculations to predict the reactivity of their carbon atoms for an attack by the iron‐oxygen species. Both F− and F0 were calculated to account for different mechanisms of substrate conversion. We show which particular initial conformations of 11‐deoxycorticosterone and which conversion paths are likely to result in the successful synthesis of aldosterone, and thereby may be representative for the mechanism of aldosterone biosynthesis by CYP11B2. Moreover, we found that the most likely path for aldosterone synthesis coincides with the substrate conformation proposed in an earlier publication (Ref.2). To summarize, we show that on a theoretical and strictly ligand‐directed basis only a limited number of reaction paths in the conversion of 11‐deoxycorticosterone to aldosterone is possible. Despite its theoretical nature, this knowledge may help to understand the catalytic function of CYP11B1 and CYP11B2. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Point atomic multipole moments for simulation of electrostatic potential and field in all‐siliceous zeolites
Authors: Larin Alexander V.
Published: May 2011

Calibration method of atomic multipole moments (AMMs) is presented with respect to geometries of all‐siliceous zeolite models obtained with X‐ray diffraction (XRD) methods. Mulliken atomic charges and AMMs are calculated for all‐siliceous types possessing small size elementary unit cells at the hybrid density functional theory (DFT) (B3LYP) and general gradient approximation (GGA) Perdew‐Burke‐Ernzerhof (PBE) levels and then used to fit the dependences versus geometry variables for the Mulliken charges and versus special coordinate for the AMMs. Fitted and exact charges and AMMs are used to compute electrostatic potential (EP) and electric field (EF) for all‐siliceous zeolites with CRYSTAL. A possibility of application of the point AMMs to quantum mechanical/molecular mechanics computations or classic simulation of physical adsorption is evaluated. The considered models expand over wide range of structural parameters and could be applied even to amorphous all‐siliceous systems. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Alkaline hydrolysis of ethylene phosphate: An ab initio study by supermolecule model and polarizable continuum approach
Authors: Xia Futing , Zhu Hua
Published: May 2011

The alkaline hydrolysis reaction of ethylene phosphate (EP) has been investigated using a supermolecule model, in which several explicit water molecules are included. The structures and single‐point energies for all of the stationary points are calculated in the gas phase and in solution at the B3LYP/6‐31++G(df,p) and MP2/6‐311++G(df,2p) levels. The effect of water bulk solvent is introduced by the polarizable continuum model (PCM). Water attack and hydroxide attack pathways are taken into account for the alkaline hydrolysis of EP. An associative mechanism is observed for both of the two pathways with a kinetically insignificant intermediate. The water attack pathway involves a water molecule attacking and a proton transfer from the attacking water to the hydroxide in the first step, followed by an endocyclic bond cleavage to the leaving group. While in the first step of the hydroxide attack pathway the nucleophile is the hydroxide anion. The calculated barriers in aqueous solution for the water attack and hydroxide attack pathways are all about 22 kcal/mol. The excellent agreement between the calculated and observed values demonstrates that both of the two pathways are possible for the alkaline hydrolysis of EP. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Molecular mechanical study of halogen bonding in drug discovery
Authors: Ibrahim Mahmoud A. A.
Published: May 2011

A halogen bond is a noncovalent bond between a halogen atom (X) and a Lewis base (Y). This type of bond is attributed to the anisotropic distribution of the charge density on the halogen atom, resulting in the formation of a positive cap (called the σ‐hole) centered on the A–X axis. The current research is the first reported molecular mechanical study of halogen bonding, the positive region centered on the halogen atom was represented by an extra‐point (EP) of charge. The correlation between the X–EP distance and the X…Y bond length was explored to determine the optimal position of the EP. A test set of 27 halogen‐containing molecules complexed to various Lewis bases was studied using molecular mechanical potentials. The molecular mechanical minimized halogen bond lengths and binding energies were in good agreement with the corresponding quantum mechanical values. The EP inclusion on the halogen atom resulted in an improvement in the accuracy of the electrostatic‐potential derived charges. The solvation free energies of halobenzene molecules relative to benzene were calculated with and without EP inclusion to assess the accuracy of the developed approach. Molecular mechanical study of halo derivatives of benzotriazole complexed to cyclin‐dependent protein kinase 2 (CDK2) was performed, and MM‐PB(GB)SA binding energies were calculated as a case study in finding potent halogenated inhibitors that can serve as antitumor drugs. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Synthesis of novel 6,7‐dihydro‐5H‐pyrimido[4,5‐e][1,4]diazepin‐8(9H)‐ones
Authors: Xiang Jinbao , Hu Xiaowei , Dang Qun , Bai Xu
Published: May 2011

A new method was developed for the synthesis of 6,7‐dihydro‐5H‐pyrimido[4,5‐e][1,4]diazepin‐8(9H)‐one derivatives. The key to construct the pyrimido[4,5‐e][1,4]diazepine core is the intramolecular amidation of N‐((4‐amino‐6‐chloropyrimidin‐5‐yl)methyl)‐substituted amino acid esters. This methodology was validated through the preparation of 13 representative 6,7‐dihydro‐5H‐pyrimido[4,5‐e][1,4]diazepin‐8(9H)‐ones in moderate to good yields. J. Heterocyclic Chem., (2011).
Development of the excretory system in the polyplacophoran mollusc,Lepidochitona corrugata: The protonephridium
Authors: Baeumler Natalie , Haszprunar Gerhard , Ruthensteiner Bernhard
Published: May 2011

A single pair of protonephridia is the typical larval excretory organ of molluscs. Their presence in postlarval developmental stages was discovered only recently. We found that the protonephridia of the polyplacophoran mollusc,Lepidochitona corrugata, achieve their most elaborate differentiation and become largest during the postlarval period. This study describes the protonephridia ofL. corrugatausing light and electron microscopy and interactive three‐dimensional visualization. We focus on the postlarval developmental period, in which the protonephridia consist of three parts: the terminal part with the ultrafiltration sites at the distal end, the voluminous protonephridial kidney, and the efferent nephroduct leading to the nephropore. The ultrafiltration sites show filtration slits between regularly arranged thin pedicles. The ciliary flame originates from both the terminal cell and the duct cells of the terminal portion. The efferent duct also shows ciliation. The most conspicuous structures, the protonephridial kidneys, are voluminous swellings composed of reabsorptive cells (“nephrocytes”). These cells exhibit strong vacuolization and an infolding system increasing the basal surface. The protonephridial kidneys, previously not reported at such a level of organization in molluscs, strikingly resemble (metanephridial) kidneys of adult molluscan excretory systems. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.
Morphological variation of the palatal organ and chewing pad of catostomidae (Teleostei: Cypriniformes)
Authors: Doosey Michael H. , Bart Henry L.
Published: May 2011

We studied the morphology and shape variation of the palatal organ and chewing pad of sucker fishes, family Catostomidae. The palatal organ is a muscularized structure that forms a large mass on the roof of the posterior part of the buccopharyngeal cavity in cypriniform fishes. It functions in coordination with the branchial arches to separate food items from inorganic debris during feeding. The palatal organ exhibits considerable variability in morphology among catostomids. It is shorter, narrower, and thinner in species of the subfamily Cycleptinae (e.g., Cycleptus elongatus) than in other catostomid subfamilies. The thickest and widest palatal organ is seen in species of the subfamily Ictiobinae (e.g., Ictiobus cyprinellus). The shape and size of the palatal organ generally varies between these extremes in species of subfamily Catostominae (e.g., Catostomus and Moxostoma species). Principal components analysis and analysis of variance has differentiated means of various palatal organ measurements for each monophyletic subfamily and tribe of Catostomidae with statistical significance. These results corroborate previously established typological classification of catostomids based on pharyngeal tooth count, pharyngeal tooth morphology, and diet. A keratinized chewing pad forms on the posterior surface of the palatal organ in catostomids or on a skeletal process in cyprinids and serves as an occlusion surface for pharyngeal teeth. The chewing pad is lunate in catostomids and generally ovoid in cyprinids. It is absent from the species of loaches (e.g., botiids, cobitids, and nemacheilids) and gyrinocheilids examined. A synonymy of terms used in the past to describe the palatal organ and chewing pad of Cypriniformes is provided. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.
Oropharyngeal morphology in the basal tortoise Manouria emys emys with comments on form and function of the testudinid tongue
Authors: Heiss Egon , Natchev Nikolay , Schwaha Thomas , Salaberger Dietmar , Lemell Patrick , Beisser Christian , Weisgram Josef
Published: May 2011

In tetrapods, the ability to ingest food on land is based on certain morphological features of the oropharynx in general and the feeding apparatus in particular. Recent paleoecological studies imply that terrestrial feeding has evolved secondarily in turtles, so they had to meet the morphological oropharyngeal requirements independently to other amniotes. This study is designed to improve our limited knowledge about the oropharyngeal morphology of tortoises by analyzing in detail the oropharynx in Manouria emys emys. Special emphasis is placed on the form and function of the tongue. Even if Manouria is considered a basal member of the only terrestrial turtle clade and was hypothesized to have retained some features reflecting an aquatic ancestry, Manouria shows oropharyngeal characteristics found in more derived testudinids. Accordingly, the oropharyngeal cavity in Manouria is richly structured and the glands are large and complexly organized. The tongue is large and fleshy and bears numerous slender papillae lacking lingual muscles. The hyolingual skeleton is mainly cartilaginous, and the enlarged anterior elements support the tongue and provide insertion sides for the well‐developed lingual muscles, which show striking differences to other reptiles. We conclude that the oropharyngeal design in Manouria differs clearly from semiaquatic and aquatic turtles, as well as from other reptilian sauropsids. J. Morphol., 2011. © 2011 Wiley‐Liss, Inc.
Additional value of gadoxetic acid‐DTPA‐enhanced hepatobiliary phase MR imaging in the diagnosis of early‐stage hepatocellular carcinoma: Comparison with dynamic triple‐phase multidetector CT imaging
Authors: Haradome Hiroki , Grazioli Luigi , Tinti Rita , Morone Mario , Motosugi Utaroh , Sano Katsuhiro , Ichikawa Tomoaki , Kwee Thomas C. , Colagrande Stefano
Published: May 2011

Purpose:

To assess the value of hepatobiliary phase gadoxetic acid (EOB)‐enhanced magnetic resonance imaging (MRI) for the diagnosis of early stage hepatocellular carcinoma (HCC) (<3 cm) compared to triple‐phase dynamic multidetector computed tomography (MDCT).

Materials and Methods:

In all, 52 patients with 60 pathologically proven HCCs underwent both EOB‐enhanced MRI and triple‐phase dynamic MDCT. Two radiologists independently and blindly reviewed three image sets: 1) MDCT, 2) dynamic MRI (unenhanced and EOB‐enhanced dynamic MR images), and 3) combined MRI (dynamic MRI + hepatobiliary phase images) using a five‐point rating scale on a lesion‐by‐lesion basis. Receiver operating characteristics (ROC) analysis was performed, and sensitivity and specificity were calculated.

Results:

The area under the ROC curve (Az) of dynamic MRI was equivalent to that of MDCT for both readers. For both readers, Az and sensitivity of combined MRI for smaller lesions (<1.5 cm) were significantly higher than that of dynamic MRI and MDCT (P < 0.0166). The majority of false‐negative nodules on dynamic MRI or MDCT (75% and 62%, respectively) were due to a lack of identified washout findings.

Conclusion:

Hepatobiliary phase images can increase the value of EOB‐enhanced MRI in the diagnosis of early stage HCC. The sensitivity and accuracy were significantly superior to MDCT for the diagnosis of lesions less than 1.5 cm. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.
Simultaneous bilateral magnetic resonance imaging of the femoral arteries in peripheral arterial disease patients
Authors: Brown Ryan , Karmonik Christof , Brunner Gerd , Lumsden Alan , Ballantyne Christie , Johnson Shawna , Wang Yi , Morrisett Joel
Published: May 2011

Purpose:

To image the femoral arteries in peripheral arterial disease (PAD) patients using a bilateral receive coil.

Materials and Methods:

An eight‐channel surface coil array for bilateral MRI of the femoral arteries at 3T was constructed and evaluated.

Results:

The bilateral array enabled imaging of a 25‐cm segment of the superficial femoral arteries (SFA) from the profunda to the popliteal. The array provided improved the signal‐to‐noise ratio (SNR) at the periphery and similar SNR in the middle of a phantom compared to three other commercially available coils (4‐channel torso, quadrature head, whole body). Multicontrast bilateral images of the in vivo SFA with 1 mm in‐plane resolution made it possible to directly compare lesions in the index SFA to the corresponding anatomical site in the contralateral vessel without repositioning the patient or coil. A set of bilateral time‐of‐flight, T1‐weighted, T2‐weighted, and proton density‐weighted images was acquired in a clinically acceptable exam time of ≈45 minutes.

Conclusion:

The developed bilateral coil is well suited for monitoring dimensional changes in atherosclerotic lesions of the SFA. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.
Distinguishing hemangiomas from malignant solid hepatic lesions: A comparison of heavily T2‐weighted images obtained before and after administration of gadoxetic acid
Authors: Ahn Sung Jun , Kim Myeong‐Jin , Hong Hye‐Suk , Ah Kim Kyung , Song Ho‐Taek
Published: May 2011

Purpose:

To compare the use of heavily T2‐weighted images obtained before and after administration of gadoxetic acid in differentiating hemangiomas from malignant solid hepatic lesions.

Materials and Methods:

Heavily T2‐weighted images (TE = 150 msec) were obtained for 70 patients (42 men and 28 women) with 74 focal hepatic lesions (25 hepatocellular carcinomas [HCC], 22 metastases, and 27 hemangiomas) ≤3 cm in diameter before and after gadoxetic acid‐enhanced dynamic magnetic resonance imaging (MRI). Quantitative analysis was performed using receiver operating characteristic (ROC) curves with lesion‐to‐liver signal intensity difference‐to‐noise ratio (SDNR) on precontrast and postcontrast images. Qualitative analysis was also performed by two blinded reviewers.

Results:

The SDNR of the solid lesions was significantly higher on the postcontrast (1.66 ± 1.18) than on the precontrast (1.38 ± 1.07) images (P = 0.0012), while the SDNR of hemangiomas was comparable for pre‐ and postcontrast images (P = 0.8164). The best SDNR cutoff values for distinguishing solid lesions from hemangiomas were ≤1.85 (Az = 0.948) for precontrast and ≤2.58 (Az = 0.901) for postcontrast images (P = 0.057). Reader performances for distinguishing hemangiomas from solid lesions were comparable between the precontrast (Az = 0.975 and 0.970 for readers 1 and 2) and postcontrast (Az = 0.977 and 0.972) images (P = 0.899 and 0.946).

Conclusion:

Heavily T2‐weighted images obtained after administration of gadoxetic acid have a diagnostic capability comparable to precontrast images for differentiating between small hemangiomas and malignant solid lesions of the liver. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.
Sex‐ and brain region‐specific role of cytochrome c oxidase in 1‐methyl‐4‐phenylpyridinium‐mediated astrocyte vulnerability
Authors: Sundar Boyalla Syama , Barbara Victor Marion , Roemgens André , Beyer Cordian , Arnold Susanne
Published: May 2011

Parkinson's disease is a neurodegenerative disorder characterized by a sex and brain region specificity, showing a higher incidence in men than in women, which is caused by cell death of mainly dopaminergic neurons in the mesencephalon. Mitochondrial toxins are often used to trigger and mimic neurodegenerative processes. Thus, systemic application of 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) induces Parkinsonian symptoms, indicating a causative or consequent involvement of mitochondria. Therefore, mitochondria of neural cells may demonstrate a sex and brain region specificity with respect to structural and functional characteristics of these organelles during toxic and degenerative processes. The application of MPTP in vivo and its toxic derivative 1‐methyl‐4‐phenylpyridinium (MPP+) in vitro represent a well‐accepted experimental model of Parkinson's disease. Aside from the known effects of MPP+ on mitochondria and neural cell survivability and with respect to the supportive role of astrocytes for neuronal function, we aimed to demonstrate the involvement of cytochrome c oxidase subunit IV isoform expression in energy and reactive oxygen species production taking part in an impairment of astrocyte survival. MPP+ caused a specific increase of COX IV‐2 transcript and protein levels in male mesencephalic astrocytes, accompanied by decreased ATP and increased reactive oxygen species levels and elevated apoptotic cell death, which were more pronounced in mesencephalic than in cortical astrocytes from male than from female mice. Our data suggest that MPP+ acts on astrocytes in a sex‐ and brain region‐specific manner involving cytochrome c oxidase isoform expression in an impairment of energy production and elevated oxidative stress levels, which represent hallmarks of neurodegenerative diseases. © 2011 Wiley‐Liss, Inc.
Thriving at work: Toward its measurement, construct validation, and theoretical refinement
Authors: Porath Christine , Spreitzer Gretchen , Gibson Cristina , Garnett Flannery G.
Published: May 2011

Thriving is defined as the psychological state in which individuals experience both a sense of vitality and learning. We developed and validated a measure of the construct of thriving at work. Additionally, we theoretically refined the construct by linking it to key outcomes, such as job performance, and by examining its contextual embeddedness. In Study 1, we conducted second‐order confirmatory factor analyses in two samples, demonstrating initial support for the two‐dimensional structure of thriving. We provided evidence for the convergent and discriminant validity of thriving in relation to theoretically related constructs, such as positive and negative affects, learning and performance goal orientations, proactive personality, and core self‐evaluations. In Study 2, across two different samples, we further assessed construct validity by establishing a relationship between thriving and career development initiative, burnout, health, and individual job performance, explaining significant variance beyond traditional attitudinal predictors, such as job satisfaction and organizational commitment. Finally, in Study 3, we focused on understanding the contextual embeddedness of thriving. We found differences in reports of thriving across two points in time, when substantial changes are occurring in peoples' work lives and across contexts (i.e., work and non‐work). Implications for theory and practice, as well as directions for future research, are discussed. Copyright © 2011 John Wiley & Sons, Ltd.
On two different objective procedures for classifying synoptic weather types over east Australia
Authors: Jiang Ningbo , Cheung Kevin , Luo Kehui , Beggs Paul J. , Zhou Wen
Published: May 2011

Synoptic weather typing depends on the method and its implementation. This paper demonstrates the utility of a 2‐phase batch self‐organising map procedure (CP2) in comparison with a procedure (CP1) consisting of T‐mode principal component analysis followed by convergent K‐means clustering, for classifying the synoptic weather types over east Australia. Four classifications were obtained for the 52‐year NCEP/NCAR dataset, one from CP1 and three from CP2. These classifications were examined in terms of grouping quality, mean type maps, type frequencies, lifetime and transitions, and in relation to the Southern Oscillation Index (SOI).

The results showed that the classifications derived from different procedures are inter‐confirmative and capture a similar set of major synoptic situations influencing east Australia, each having counterparts in previous studies and conforming well to local synoptic experience. In particular, this study demonstrates that CP2 is a promising tool for the purpose of weather typing with a two‐fold utility: CP2 can perform data projection (neighbourhood width > = 1) and provide a flexible means for visualising the broad distribution of the daily weather patterns in the dataset; and the procedure can also conduct cluster analysis (neighbourhood width = 0) and produce results equivalent to those from CP1. It was found that performing data clustering or data projection may affect the inference associated with type frequencies. While focusing on methodology, the analysis has also shown that the frequency of synoptic weather types fluctuates on the seasonal, interannual, and decadal scales. From the 1970s to 1995 there was a decline in the occurrence of a few weather types associated with an east‐coast trough extending over New South Wales from the north, and a slight increase in the activity of some anticyclonic types. Significant correlations were also identified between SOI and frequencies of synoptic weather types on the annual and seasonal timescales. Copyright © 2011 Royal Meteorological Society
Differential gene expression and immunolocalization of insulin‐like growth factors and insulin‐like growth factor binding proteins between experimental nonunions and standard healing fractures
Authors: Koh Akihiro , Niikura Takahiro , Lee Sang Yang , Oe Keisuke , Koga Takaaki , Dogaki Yoshihiro , Kurosaka Masahiro
Published: May 2011

Insulin‐like growth factors (IGF‐I/II) are important growth factors in bone, and their actions are regulated by six IGF binding proteins (IGFBPs). However, little is known about their exact functions in fracture healing. The aim of this study was to compare the gene expression and immunolocalization of IGFs and IGFBPs between standard healing fractures and nonunions using rat experimental models. Standard healing fractures and nonunions produced by periosteal cauterization at the fracture site were created in rat femurs. At postfracture days 3, 7, 10, 14, 21, and 28, total RNA was extracted from the callus of the healing fractures and the fibrous tissue of the nonunions, and gene expression were analyzed by real‐time PCR. Additionally, immunolocalization of these proteins was studied by immunohistochemistry at postfracture days 7, 14, and 21. In nonunions, the gene expression of IGF‐I/II and IGFBP‐6 was significantly higher, and that of IGFBP‐5 was significantly lower at several time points. The immunolocalization of IGF‐I/II and IGFBP‐5 was widely distributed in both models. In contrast, that of IGFBP‐6 was barely detected in the fracture callus. In conclusion, our results suggest that IGFs/IGFBPs may have important roles not only in fracture healing but also in nonunion formation. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1820–1826, 2011
Phonons in SiAs: Raman scattering study and DFT calculations
Authors: Kutzner Jürgen , Kortus Jens , Pätzold Olf , Wunderwald Ulrike , Irmer Gert
Published: May 2011

We present experimental Raman scattering results on single‐crystal silicon monoarsenide (SiAs). Based on a comparison between Raman measurements and first‐principles density functional theory calculations, we found evidence that SiAs will occur in a monoclinic crystal structure rather than an orthorhombic one as has been discussed in the literature. Further, we provide a detailed discussion of the vibrational properties of the monoclinic structure. Copyright © 2011 John Wiley & Sons, Ltd.
Oxygen vacancy‐induced microstructural changes of annealed CeO2−xnanocrystals
Authors: Aškrabić S. , Dohčević‐Mitrović Z. , Kremenović A. , Lazarević N. , Kahlenberg V. , Popović Z. V.
Published: May 2011

Nanocrystalline ceria (CeO2) is known for its ionic conductivity and oxygen storage properties, which depend on the presence of oxygen ion vacancies. The vacancies cause several important changes in CeO2involving microstrain, electronic structure, magnetic properties, etc. In this article, we focus our attention to the microstructural changes of nanocrystalline CeO2−xannealed at different temperatures in the range 200–500 °C. Structural and vibrational properties were investigated by X‐ray diffraction and Raman spectroscopy. It was observed that the content of oxygen vacancies changed significantly with increasing annealing temperature, which plays an important role in the observed microstructural changes of the annealed samples. We demonstrate that the observed microstrain changes, because of variable defect content, dominate over the crystallite size effect. This finding is opposite to the conclusions made by several other authors. A new mode, classified as a probable surface mode, was observed in the Raman spectra at ∼480 cm−1, the appearance of which can be explained by the large defective structure and disorder in the ceria lattice. Copyright © 2011 John Wiley & Sons, Ltd.
Shell‐isolated nanoparticle enhanced Raman spectroscopy (SHINERS) investigation of benzotriazole film formation on Cu(100), Cu(111), and Cu(poly)
Authors: Honesty Nicole R. , Gewirth Andrew A.
Published: May 2011

Benzotriazole (BTAH) is well known as an effective corrosion inhibitor for Cu because of its ability to make a coordination polymer film on the surface that provides a barrier to Cu oxidation. BTA− film formation was investigated on single‐crystal and polycrystalline Cu surfaces with shell‐isolated nanoparticle enhanced Raman spectroscopy (SHINERS) using silica‐encapsulated Au nanoparticles. Potential‐dependent spectra display reversible film formation on polycrystalline Cu and irreversible film formation on single‐crystal Cu. Grain boundaries leading to smaller BTA−‐Cu oligomers are proposed to be the reason for cathodic degradation of the BTA− polymeric films on polycrystalline Cu. Copyright © 2011 John Wiley & Sons, Ltd.
Synthesis of ionic liquid‐bonded organic‐silica hybrid monolithic column for capillary electrochromatography
Authors: Han Haifeng , Li Jing , Wang Xusheng , Liu Xia , Jiang Shengxiang
Published: May 2011

An ionic liquid (IL) was introduced into the organic‐silica hybrid monolithic column as the stationary phase for capillary electrochromatography (CEC). The monolithic silica matrix containing chloropropyl functional group was prepared by the in situ co‐condensation of tetramethoxysilane and (3‐chloropropyl)‐trimethoxysilane via a sol–gel process and chemical modification with N‐methylimidazole. The electroosmotic flow of the IL‐modified hybrid monolithic column was reversed at acidic pH and the morphology of the column was characterized by scanning electron microscope. Four aromatic hydrocarbons were completely separated with 40% acetonitrile phosphate buffer as the mobile phase and seven inorganic ions were efficiently separated with the phosphate buffer on the column in CEC. Reproducibilities of migration time for four aromatic hydrocarbons (benzene, naphthalene, anthracene, chrysene) were acceptable on IL‐modified hybrid monolithic columns. Relative standard deviations of run‐to‐run (n=5), peak area‐to‐peak area (n=5), day‐to‐day (n=3) and column‐to‐column (n=3) were in the range of 0.72–0.88, 1.47–5.40, 2.44–4.99 and 3.01–8.11%, respectively.
QuEChERS‐based extraction procedure for multifamily analysis of phytohormones in vegetables by UHPLC‐MS/MS
Authors: Flores María Isabel Alarcón , Romero‐González Roberto , Frenich Antonia Garrido , Vidal José Luis Martínez
Published: May 2011

A new method has been developed and validated for the simultaneous analysis of different phytohormones (auxins, cytokinins and gibberellins) in vegetables. The compounds were extracted using a QuEChERS‐based method (acronym of quick, easy, cheap, effective, rugged and safe). The separation and determination of the selected phytohormones were carried out by ultra high‐performance liquid chromatography coupled to tandem mass spectrometry (UHPLC‐MS/MS), using electrospray ionization source (ESI) in positive and negative ion modes. The method was validated and mean recoveries were evaluated at three concentration levels (50, 100 and 250 μg/kg), ranging from 75 to 110% at the three levels assayed. Intra‐ and interday precisions, expressed as relative standard deviations (RSDs), were lower than 20 and 25%, respectively. Limits of quantification (LOQs) were equal or lower than 10 μg/kg. The developed procedure was applied to seven courgette samples, and naphthylacetic acid, naphthylacetamide and benzyladenine were found in some of the analysed samples.
Effects of functional monomers on retention behavior of small and large molecules in monolithic capillary columns at isocratic and gradient conditions
Authors: Urban Jiří , Jandera Pavel , Langmaier Pavel
Published: May 2011

The polarity of (poly)methacrylate monolithic capillary columns was varied by using alkylmethacrylate monomers with butyl, cyclohexyl, 2‐ethylhexyl, lauryl, and stearyl functional groups in the polymerization mixture. The hydrodynamic properties, as well as the retention characteristics in RP‐LC of small molecules (alkylbenzenes) and of proteins under gradient elution conditions were studied. The RP selectivity depends on the type of alkyl chain in methacrylate monomer; however, there was no direct correlation between the size of the monomer molecule and methylene or aromatic selectivity of the monlithic column. The lowest selectivity was found for column based on lauryl methacrylate monomer. On the other hand, butyl methacrylate column shows high phenyl selectivity and the column with stearyl methacrylate possesses the highest methylene selectivity for small molecules. The retention increases with longer alkyl chain in methacrylate monomer, especially for high molar mass proteins on all prepared columns and showed gradient elution behavior of proteins in agreement with the linear solvent strength gradient model. The poly(laurylmethacrylate) column showed lowest hydrophobicity but best efficiency for proteins of all columns tested.
A Nanocage for Nanomedicine: Polyhedral Oligomeric Silsesquioxane (POSS)
Authors: Ghanbari Hossein , Cousins Brian G. , Seifalian Alexander M.
Published: May 2011

Ground‐breaking advances in nanomedicine (defined as the application of nanotechnology in medicine) have proposed novel therapeutics and diagnostics, which can potentially revolutionize current medical practice. Polyhedral oligomeric silsesquioxane (POSS) with a distinctive nanocage structure consisting of an inner inorganic framework of silicon and oxygen atoms, and an outer shell of organic functional groups is one of the most promising nanomaterials for medical applications. Enhanced biocompatibility and physicochemical (material bulk and surface) properties have resulted in the development of a wide range of nanocomposite POSS copolymers for biomedical applications, such as the development of biomedical devices, tissue engineering scaffolds, drug delivery systems, dental applications, and biological sensors. The application of POSS nanocomposites in combination with other nanostructures has also been investigated including silver nanoparticles and quantum dot nanocrystals. Chemical functionalization confers antimicrobial efficacy to POSS, and the use of polymer nanocomposites provides a biocompatible surface coating for quantum dot nanocrystals to enhance the efficacy of the materials for different biomedical and biotechnological applications. Interestingly, a family of POSS‐containing nanocomposite materials can be engineered either as completely non‐biodegradable materials or as biodegradable materials with tuneable degradation rates required for tissue engineering applications. These highly versatile POSS derivatives have created new horizons for the field of biomaterials research and beyond. Currently, the application of POSS‐containing polymers in various fields of nanomedicine is under intensive investigation with expectedly encouraging outcomes.

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Crystalline Complex of Syndiotactic Polystyrene with Poly(ethylene Glycol) Dimethyl Ethers
Authors: Kaneko Fumitoshi , Sasaki Keita
Published: May 2011

It has been clarified that syndiotactic polystyrene (sPS) forms co‐crystalline structures with polyethylene glycol dimethyl ethers (PEGDMEs) with molecular weights ranging from 178 to 1 000 g · mol−1 through a guest exchange procedure assisted by a plasticizing agent. The PEGDME molecules are incorporated into the spaces between sPS polymer sheets consisting of (T2G2)2 helices. The results of X‐ray diffraction and gravimetric measurements suggest that one or less molecules are included per unit cell for PEGDME with average molecular weight of 1 000 g · mol−1, which indicates the possibility that longer polymeric molecules can be introduced into sPS lattices with multiple site occupation.

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Output error estimation strategies for discontinuous Galerkin discretizations of unsteady convection‐dominated flows
Authors: Fidkowski Krzysztof J.
Published: May 2011

We study practical strategies for estimating numerical errors in scalar outputs calculated from unsteady simulations of convection‐dominated flows, including those governed by the compressible Navier–Stokes equations. The discretization is a discontinuous Galerkin finite element method in space and time on static spatial meshes. Time‐integral quantities are considered for scalar outputs and these are shown to superconverge with temporal refinement. Output error estimates are calculated using the adjoint‐weighted residual method, where the unsteady adjoint solution is obtained using a discrete approach with an iterative solver. We investigate the accuracy versus computational cost trade‐off for various approximations of the fine‐space adjoint and find that exact adjoint solutions are accurate but expensive. To reduce the cost, we propose a local temporal reconstruction that takes advantage of superconvergence properties at Radau points, and a spatial reconstruction based on nearest‐neighbor elements. This inexact adjoint yields output error estimates at a computational cost of less than 2.5 times that of the forward problem for the cases tested. The calculated error estimates account for numerical error arising from both the spatial and temporal discretizations, and we present a method for identifying the percentage contributions of each discretization to the output error. Copyright © 2011 John Wiley & Sons, Ltd.
Limitations on dynamic excess carrier lifetime calibration methods
Authors: Sinton Ronald A. , Trupke Thorsten
Published: May 2011

Comparison of minority carrier lifetime measurements carried out in transient mode with measurements performed under steady‐state conditions allows determination of the calibration constants needed in non‐transient measurements. In this letter, we point out practical scenarios in which the assumptions underlying this approach break down, resulting in significant experimental errors. Specific examples for crystalline silicon wafers will be discussed to provide some guidelines on practical limitations of this calibration approach. Large errors are possible for wafers with high surface recombination velocity as might be the case for incoming wafers for a solar cell production line. Copyright © 2011 John Wiley & Sons, Ltd.
Eukaryotic cell lines as a sensitive layer for direct monitoring of carbon monoxide
Authors: Bohrn Ulrich , Stütz Evamaria , Fleischer Maximilian , Schöning Michael J. , Wagner Patrick
Published: May 2011

In the past years, whole cell gas toxicity assays have been developed in order to study the harmful effects of gaseous chemicals. Cells are incubated with nutrition medium supplemented with the gaseous substances to be tested. These methods are not feasible for the examination of toxic gases, which are insoluble in water. Carbon monoxide (CO), a poorly soluble and toxic gas (lethal dose 1 vol% for some minutes) has been chosen as a model gas. Besides its binding to hemoglobin, it also leads to an inhibition of cytochrome c oxidase in the mitochondrial respiratory chain of living cells. Thus, a decrease in the respiratory behavior of eukaryotic cells indicates the presence of CO in a gaseous phase. Based on the Bionas® 2500 analyzing system, a device to measure the metabolic and morphological effects, caused by direct gas exposure on eukaryotic cells was established. The gaseous substances directly contact the eukaryotic cell line V79 (Chinese hamster lung fibroblast) without interfering liquid phase in between. Beside the measurement of oxygen consumption also acidification and impedance changes of the cell culture are detected by a metabolic sensor chip. In order to increase the stability different chip surface coatings like collagen A and poly‐L‐lysin (PLL) were used. Adhesion coating leads to a tighter junction of the cells to the sensor chip surface and thus enables higher stability of the confluent cell monolayer towards the gaseous flow during the gas exposure. The method reported here has the potential to become a valuable means for rapid monitoring of toxic compounds in gaseous phases.