bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanistic Studies on Chabazite‐Type Methanol‐to‐Olefin Catalysts: Insights from Time‐Resolved UV/Vis Microspectroscopy Combined with Theoretical Simulations
Authors: Van Speybroeck Veronique , Hemelsoet Karen , De Wispelaere Kristof , Qian Qingyun , Van der Mynsbrugge Jeroen , De Sterck Bart , Weckhuysen Bert M. , Waroquier Michel
Published: November 2012

The formation and nature of active sites for methanol conversion over solid acid catalyst materials are studied by using a unique combined spectroscopic and theoretical approach. A working catalyst for the methanol‐to‐olefin conversion has a hybrid organic–inorganic nature in which a cocatalytic organic species is trapped in zeolite pores. As a case study, microporous materials with the chabazite topology, namely, H‐SAPO‐34 and H‐SSZ‐13, are considered with trapped (poly)aromatic species. First‐principle rate calculations on methylation reactions and in situ UV/Vis spectroscopy measurements are performed. The theoretical results show that the structure of the organic compound and zeolite composition determine the methylation rates: 1) the rate increases by 6 orders of magnitude if more methyl groups are added on benzenic species, 2) transition state selectivity occurs for organic species with more than one aromatic core and bearing more than three methyl groups, 3) methylation rates for H‐SSZ‐13 are approximately 3 orders of magnitude higher than on H‐SAPO‐34 owing to its higher acidity. The formation of (poly)aromatic cationic compounds can be followed by using in situ UV/Vis spectroscopy because these species yield characteristic absorption bands in the visible region of the spectrum. We have monitored the growth of characteristic peaks and derived activation energies of formation for various sets of (poly)aromatic compounds trapped in the zeolite host. The formation–activation barriers deduced by using UV/Vis microspectroscopy correlate well with the activation energies for the methylation of the benzenic species and the lower methylated naphthalenic species. This study shows that a fundamental insight at the molecular level can be obtained by using a combined in situ spectroscopic and theoretical approach for a complex catalyst of industrial relevance.
Immobilization of Styrene‐Substituted 1,3,4‐Oxadiazoles into Thermoreversible Luminescent Organogels and Their Unexpected Photocatalyzed Rearrangement
Authors: Dumur Frédéric , Contal Emmanuel , Wantz Guillaume , Phan Trang N. T. , Bertin Denis , Gigmes Didier
Published: November 2012

A series of styrene‐substituted 1,3,4‐oxadiazoles has been designed and investigated as new low‐molecular‐weight organogelators. The photophysical properties of the resulting thermoreversible organogels have been characterized by UV/Vis absorption and luminescence spectroscopies. Surprisingly, the gelation ability of the oxadiazoles depended on the presence of the styrene moiety as gelation of the investigated oxadiazoles did not take place in its absence. Gel formation was accompanied by a modification of the fluorescence of the organogelators in the supramolecular state. UV irradiation of the gels caused a rearrangement of the immobilized 1,3,4‐oxadiazoles bearing a styrene moiety by a tandem [4+2] and [3+2] cascade reaction. Structure modification and color change of the gels were also evident upon irradiation.
A Click Approach to Polymetallic Chromium(0) and Tungsten(0) Fischer‐Carbene Complexes and Their Use in the Synthesis of Functionalized Polymetallic MetalCarbene Complexes
Authors: Baeza Beatriz , Casarrubios Luis , Sierra Miguel A.
Published: November 2012

Alkynylamino Cr0 and W0 Fischer carbenes undergo a CuAAC reaction with a diverse range of di‐, tri‐, and tetra‐azides to produce polymetallic chromium(0) and tungsten(0) (Fischer)‐carbene complexes in good‐to‐excellent yields. This method is simple, versatile, and is suitable for the preparation of a diverse range of structures with a high level of symmetry. Moreover, the resulting polymetallic carbene complexes are suitable partners for the peripheral functionalization of the metal nuclei, whilst retaining the metal fragment. This fact has been demonstrated in a simultaneous Pauson–Khand reaction, which, in some cases, allows for the generation of four bicyclic [5,5] rings on the periphery of a tetrametallic molecule in a process that involves the formation of 12 new CC bonds, with four simultaneous CO‐insertion processes. The electrochemistry of the polymetallic Fischer carbenes show completely independent behavior for each nucleus, as well as an anomalous observation of the reversible oxidation of the allyl substituents, which has not been reported before in this class of chemistry.
1‐(2′‐Anilinyl)prop‐2‐yn‐1‐ol Rearrangement for Oxindole Synthesis
Authors: Kothandaraman Prasath , Koh Bing Qin , Limpanuparb Taweetham , Hirao Hajime , Chan Philip Wai Hong
Published: November 2012

A synthetic method that relies on NIS (N‐iodosuccinimide)‐mediated cycloisomerization reactions of 1‐(2′‐anilinyl)prop‐2‐yn‐1‐ols to gem‐3‐(diiodomethyl)indolin‐2‐ones and 2‐(iodomethylene)indolin‐3‐ones has been developed. The reactions were shown to be chemoselective, with secondary and tertiary alcoholic substrates exclusively giving the 3‐ and 2‐oxindole products, respectively. In the case of the latter, the transformation features an unprecedented double 1,2‐OH and 1,2‐alkyl migration relay. Density functional theory (DFT) calculations based on proposed iodoaminocyclization species provide insight into this unique divergence in product selectivity.
Exploring the Palladium and PlatinumBis(pyridine) Complex Motif by NMR Spectroscopy, X‐ray Crystallography, (Tandem) Mass Spectrometry, and Isothermal Titration Calorimetry: Do Substituent Effects Follow Chemical Intuition?
Authors: Weilandt Torsten , Löw Nora L. , Schnakenburg Gregor , Daniels Jörg , Nieger Martin , Schalley Christoph A. , Lützen Arne
Published: November 2012

A series of ten palladiumbis(pyridine) complexes, as well as their corresponding platinum complexes, have been synthesized. The pyridine ligands in each series carried different σ‐donor and/or π‐acceptor/donor substituents at the para‐position of their pyridine rings. These complexes were analysed by NMR spectroscopy, X‐ray crystallography, (tandem) MS, and isothermal titration calorimetry (ITC) to validate whether these methods allowed us to obtain a concise and systematic picture of the relative and absolute thermodynamic stabilities of the complexes, as determined by the electronic effects of the substituents. Interestingly, the NMR spectroscopic data hardly correlated with the expected substituent effects but the heteronuclear platinumphosphorus coupling constants did. Crystallographic data were found to be blurred by packing effects. Instead, tandem MS and ITC data were in line with each other and followed the expected trends.
Synthesis, Structures and Reactivity of Lanthanoid(II) Formamidinates of Varying Steric Bulk
Authors: Cole Marcus L. , Deacon Glen B. , Forsyth Craig M. , Junk Peter C. , Konstas Kristina , Wang Jun , Bittig Henry , Werner Daniel
Published: November 2012

New reactive, divalent lanthanoid formamidinates [Yb(Form)2(thf)2] (Form=[RNCHNR]; R=o‐MeC6H4 (o‐TolForm; 1), 2,6‐Me2C6H3 (XylForm; 2), 2,4,6‐Me3C6H2 (MesForm; 3), 2,6‐Et2C6H3 (EtForm; 4), o‐PhC6H4 (o‐PhPhForm; 5), 2,6‐iPr2C6H3 (DippForm; 6), o‐HC6F4 (TFForm; 7)) and [Eu(DippForm)2(thf)2] (8) have been prepared by redox transmetallation/protolysis reactions between an excess of a lanthanoid metal, Hg(C6F5)2 and the corresponding formamidine (HForm). X‐ray crystal structures of 2–6 and 8 show them to be monomeric with six‐coordinate lanthanoid atoms, chelating N,N′‐Form ligands and cis‐thf donors. However, [Yb(TFForm)2(thf)2] (7) crystallizes from THF as [Yb(TFForm)2(thf)3] (7 a), in which ytterbium is seven coordinate and the thf ligands are “pseudo‐meridional”. Representative complexes undergo CX (X=F, Cl, Br) activation reactions with perfluorodecalin, hexachloroethane or 1,2‐dichloroethane, and 1‐bromo‐2,3,4,5‐tetrafluorobenzene, giving [Yb(EtForm)2F]2 (9), [Yb(o‐PhPhForm)2F]2 (10), [Yb(o‐PhPhForm)2Cl(thf)2] (11), [Yb(DippForm)2Cl(thf)] (12) and [Yb(DippForm)2Br(thf)] (16). X‐ray crystallography has shown 9 to be a six‐coordinate, fluoride‐bridged dimer, 12 and 16 to be six‐coordinate monomers with the halide and thf ligands cis to each other, and 11 to have a seven‐coordinate Yb atom with “pseudo‐meridional” unidentate ligands and thf donors cis to each other. The analogous terbium compound [Tb(DippForm)2Cl(thf)2] (13), prepared by metathesis, has a similar structure to 11. CBr activation also accompanies the redox transmetallation/protolysis reactions between La, Nd or Yb metals, Hg(2‐BrC6F4)2, and HDippForm, yielding [Ln(DippForm)2Br(thf)] complexes (Ln=La (14), Nd (15), Yb (16)).
Main‐Chain Linear Polyrotaxanes: Synthesis, Characterization, and Conformational Modulation
Authors: Han Ji‐Min , Zhang Yong‐Hong , Wang Xiao‐Ye , Liu Chen‐Jiang , Wang Jie‐Yu , Pei Jian
Published: November 2012

Two functional main‐chain linear polyrotaxanes, one a covalent polymeric chain that threads through many macrocycles (P1) and the other a poly[n]rotaxane chain that is composed of many repeating rotaxane units (P2), were synthesized by employing strong crown‐ether/ammonium‐based (DB24C8/DBA) host–guest interactions and click chemistry. Energy transfer between the wheel and axle units in both polyrotaxanes was used to provide insight into the conformational information of their resulting polyrotaxanes. Steady‐state and time‐resolved spectroscopy were performed to understand the conformation differences between polymers P1 and P2 in solution. Additional investigations by using dynamic/static light scattering and atomic force microscopy illustrated that polymer P1 was unbending and had a rigid rod‐like structure, whilst polymer P2 was curved and flexible. This flexible topology facilitated the self‐assembly of polymer P2 into relatively large ball‐shaped particles. In addition, the energy transfer between the wheel and axle units was controlled by the addition of specific anions or base. The anion‐induced energy enhancement was attributed to a change in electrostatic interactions between the polymer chains. The base‐driven molecular shuttle broke the DB24C8/DBA host–guest interactions. These results confirm that both intra‐ and intermolecular electrostatic interactions are crucial for modulating conformational topology, which determines the assembly of polyrotaxanes in solution.
Laser Spectroscopic Study of Cold Host–Guest Complexes of Crown Ethers in the Gas Phase
Authors: Inokuchi Yoshiya , Kusaka Ryoji , Ebata Takayuki , Boyarkin Oleg V. , Rizzo Thomas R.
Published: November 2012

A laser spectroscopic study on the structure and dynamics of cold host–guest inclusion complexes of crown ethers (CEs) with various neutral and ionic species in the gas phase is presented. The complexes with neutral guest species are formed by using supersonic free jets, and those with ionic species are generated with electrospray ionization combined with a cold 22‐pole ion trap. For CEs, various sizes of 3n‐crown‐n ethers (n=4, 5, 6, and 8) and their benzene‐substituted species are used. For the guest species, water, methanol, ammonia, acetylene, and phenol are employed as neutral guest species, and for charged guest species, alkali metal cations are chosen. The electronic and vibrational spectra of the complexes are measured by using various laser spectroscopic methods; electronic spectra for the neutral complexes are measured by laser‐induced fluorescence. Discrimination of different species such as conformers is performed by ultraviolet–ultraviolet hole‐burning spectroscopy. The vibrational spectra of selected species are observed by infrared–ultraviolet double‐resonance (IR–UV DR) spectroscopy. For the ionic complexes, ultraviolet photodissociation and IR–UV DR spectroscopy are applied. The complex structures are determined by comparing the observed spectra with those of possible structures obtained by density functional theory calculations. How the host CEs change their conformation or which conformer prefers to form unique inclusion complexes are discussed. These results reveal the key interactions for forming special complexes leading to molecular recognition.
Photoinduced Triplet–Triplet Energy Transfer in a 2‐Ureido‐4(1H)‐Pyrimidinone‐Bridged, Quadruply Hydrogen‐Bonded Ferrocene–Fullerene Assembly
Authors: Feng Ke , Yu Mao‐Lin , Wang Su‐Min , Wang Ge‐Xia , Tung Chen‐Ho , Wu Li‐Zhu
Published: November 2012

2‐Ureido‐4(1H)‐pyrimidinone‐bridged ferrocene–fullerene assembly I is designed and synthesized for elaborating the photoinduced electron‐transfer processes in self‐complementary quadruply hydrogen‐bonded modules. Unexpectedly, steady‐state and time‐resolved spectroscopy reveal an inefficient electron‐transfer process from the ferrocene to the singlet or triplet excited state of the fullerene, although the electron‐transfer reactions are thermodynamically feasible. Instead, an effective intra‐assembly triplet–triplet energy‐transfer process is found to be operative in assembly I with a rate constant of 9.2×105 s−1 and an efficiency of 73 % in CH2Cl2 at room temperature.
Serum adipokines as biomarkers of beta‐cell function in patients with type 1 diabetes: positive association with leptin and resistin and negative association with adiponectin
Authors: Pham Minh Nguyet , Kolb Hubert , Mandrup‐Poulsen Thomas , Battelino Tadej , Ludvigsson Johnny , Pozzilli Paolo , Roden Michael , Schloot Nanette C. ,   European C‐Peptide Trial
Published: November 2012

Background

We investigated the adipokines adiponectin, leptin and resistin as serum biomarkers of beta‐cell function in patients with type 1 diabetes.

Methods

One hundred and eighteen patients with type 1 diabetes (20.3 ± 7.5 years) diagnosed <5 years underwent standardized mixed meal test (MMTT) for 2 h. Systemic concentrations of C‐peptide, adiponectin, leptin and resistin obtained during MMTT were measured and compared between patient groups by multiple regression analysis.

Results

Patients were divided by their adipokine levels in subgroups above or below the median level (‘high versus low’). High adiponectin levels (>10.6 µg/mL) were associated with lower C‐peptide compared to the low adiponectin subgroup (p < 0.03). Increased leptin or resistin concentrations associated positively with beta‐cell function even after adjustment for metabolic confounders (p < 0.04). The described associations between adipokines and C‐peptide concentrations persisted in Spearman correlation tests (p < 0.05). Serum adipokines fell during MMTT (p < 0.05).

Conclusions

Serum adipokine levels differentially correlate with beta‐cell function in type 1 diabetes independent of BMI or metabolic control. Serum adipokines should be investigated as biomarkers of beta‐cell function in prospective studies and intervention trials in type 1 diabetes. Copyright © 2012 John Wiley & Sons, Ltd.
Evolution of sex comb from the primitive bristle pattern in drosophila is associated with modification in the developmental regulatory protein dachshund
Authors: Devi Thangjam Ranjita , Amruthavalli C. , Shyamala B.V.
Published: November 2012

Sex comb is a recently evolved male specific character confined to the Sophophoran group of Drosophila. Such innovations in phenotypes as Waddington proposed, are, outcome of “canalization” in developmental pathways that occur due to mutations creating “choice points” in genetic regulatory pathways. Our interest in the present study is to understand the shifts in genetic network, which has lead to the origin of sex comb from the basic bristle pattern that is seen in rest of the members of Drosophilidae. Here we have made a comparative analysis of expression of some of the key regulators of sex comb morphogenesis, between D. melanogaster and a group of selected species, which primitively lack sex comb. Sex combs reduced (Scr), dachshund (dac), and bric‐a‐brac (bab) gene expression were studied. We show that, primitive bristle pattern is marked by a strikingly down regulated expression of Sex combs reduced in the first tarsal segment of the prothoracic leg discs of male flies. Further a remarkable change with respect to Dachshund, an activator of sex combs reduced gene in the sex comb regulatory pathway, is seen. This is attributed to changes in DAC protein that might have taken place between the two groups of species. bric‐a‐brac does not reveal any significant expression modulation between the sex comb bearing and the primitive patterned species. Earlier works had shown that within the Sophophoran group, dynamic changes in SCR expression is responsible for the diversity seen in sex comb morphology, where as no such variation is witnessed with respect to DAC expression. Our findings have demonstrated that the scenario is different between the group primitively lacking sex comb and D. melanogaster wherein an obvious change in the protein has taken place. genesis 51:97–109,
2013, 2013. © 2012 Wiley Periodicals, Inc.
{Ce10Mn8}: Cerium Analogues of the Decavanadate Archetype
Authors: Malaestean Iurie L. , Ellern Arkady , Kögerler Paul
Published: November 2012

In the presence of structure‐directing isobutyrate (ib) ligands, CeIII and MnII salts undergo a sequence of oxidation and condensation steps, which result in the intermittent formation of the neutral coordination cluster [Mn10O2(ib)18(Hib)2], followed by Mn‐decorated {Ce10Mn8} clusters. Their common inorganic {CeIV10MnII2MnIII6O18} core features a cerium oxide substructure with a decavanadate‐type metal framework, which showcases that molecular cerium oxide structures indeed can adopt certain structural principles of classical polyoxometalates. In addition, we identified the exact composition and structure of the precursor “manganese isobutyrate”, which actually consists of [Mn6(ib)12(Hib)6] macrocycles.
Synthesis of the N‐Substituted Pyridin‐1(2H)‐one Framework by Ligand‐Assisted Pd‐Catalyzed Reactions
Authors: Zhou Kang , Wen Ping , Chen Wenlin , Ma Chaowei , Huang Guosheng
Published: November 2012

An efficient Pd‐catalyzed method for the synthesis of N‐substituted pyridin‐1(2H)‐ones was developed. The corresponding derivatives, which can be found in numerous biologically active compounds, were obtained in good to excellent yields. A possible mechanism for this reaction is discussed.
Predicting the disorder–order transition of dielectrophoretic colloidal assembly with dielectric spectroscopy
Authors: Beltramo Peter J. , Furst Eric M.
Published: November 2012

The dielectrophoretic assembly of colloidal suspensions into crystalline arrays is described by a master scaling that collapses the disorder–order transition as a function of field strength, frequency, and particle size. This master scaling has been verified for particle diameters ranging from 2a = 200 nm to 3 μm by light scattering (Lumsdon et al., Langmuir 2004, 20, 2108–2116; McMullan and Wagner, Langmuir 2012, 28, 4123–4130), optical laser tweezer measurements (Mittal et al., J. Chem. Phys. 2008, 129, 064513), and small‐angle neutron scattering (McMullan and Wagner, Soft Matter 2010, 6, 5443–5450). In this work, we reconcile the empirical phase diagram with direct measurements of the colloid polarizability using dielectric spectroscopy. Dielectric spectroscopy confirms the origin of the order–disorder transition frequency dependence, including its quadratic scaling with particle radius, a2, and provides an alternative method to search for optimal self‐assembly conditions.
Genetic and epigenetic alterations of WWOX in the development of gastric cardia adenocarcinoma
Authors: Guo Wei , Dong Zhiming , Dong Yuran , Guo Yanli , Kuang Gang , Yang Zhibin
Published: November 2012

WWOX is a tumor suppressor gene that maps to the common fragile site FRA16D and is involved in carcinogenesis and cancer progression in many different carcinomas. Reduced WWOX expression is associated with more aggressive phenotypes and poor patient outcomes in several cancers. The present study was conducted in order to elucidate more precisely the genetic and epigenetic alterations of WWOX that play a role in gastric cardia adenocarcinoma (GCA) carcinogenesis in a population from Northern China. Polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP), PCR‐simple sequence length polymorphism (PCR‐SSLP), and methylation specific PCR (MSP) methods were used to characterize polymorphisms in the rs3764340, rs2548861, and rs1079635 loci, the level of loss of heterozygosity (LOH), and methylation status of WWOX, respectively. Protein and mRNA expression of WWOX in GCA tissues was quantified by immunohistochemistry and reverse transcription‐PCR (RT‐PCR). Family history of upper gastrointestinal cancer (UGIC) significantly increased the risk of developing GCA. The CG+GG genotype of rs3764340 and GT or TT genotype of rs2548861 significantly elevated the risk of developing GCA. LOH at the WWOX locus was observed in 45.6% tumors. The promoter and exon 1 methylation frequency of WWOX in GCA tissues was significantly higher than in corresponding normal tissues and was associated with UGIC family history. Protein and mRNA expression of WWOX was reduced in GCA tumor tissues and was associated with LOH and methylation of the gene. These results indicate that WWOX may play an important role in GCA especially in individuals with UGIC family history. Environ. Mol. Mutagen., 2013. © 2012 Wiley Periodicals, Inc.
Effect of TiO2 scaffolds coated with alginate hydrogel containing a proline‐rich peptide on osteoblast growth and differentiation in vitro
Authors: Rubert M. , Pullisaar H. , Gómez‐Florit M. , Ramis J. M. , Tiainen H. , Haugen H. J. , Lyngstadaas S. P. , Monjo M.
Published: November 2012

The aim of this study was to investigate the effect of TiO2 scaffold (SC) coated with an alginate hydrogel containing a proline‐rich peptide (P2) on osteoblast proliferation and differentiation in vitro. Peptide release was evaluated and a burst release was observed during the first hours of incubation, and then progressively released overtime. No changes were observed in the cytotoxicity after 48 h of seeding MC3T3‐E1 cells on the coated and uncoated TiO2 SC. The amount of cells after 7 days was higher on uncoated TiO2 SC than on alginate‐coated TiO2 SC, measured by DNA content and scanning electron microscope imaging. In addition, while lower expression of integrin beta1 was detected for alginate‐coated TiO2 SC at this time point, similar gene expression was observed for other integrins, fibronectin‐1, and several osteoblast differentiation markers. After 21 days, gene expression of integrin beta3, fibronectin‐1, osterix, and collagen‐I was increased in alginate‐coated compared to TiO2 SC. Moreover, increased gene expression of integrin alpha8, bone morphogenetic protein 2, interleukin‐6, and collagen‐I was found on P2 alginate‐coated TiO2 SC compared to alginate‐coated TiO2 SC. In conclusion, our results indicate that alginate‐coated TiO2 SC can act as a matrix for delivery of proline‐rich peptides increasing osteoblast differentiation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
Mathematical modeling of RDC column in extraction of base oil and computing of the energy saving
Authors: FakhrHoseini Seyed Mousa , Tavakkoli Touraj , Hatamipour Mohammad Sadegh , Mehrkesh Amir Hossein
Published: November 2012

Background

A mathematical modeling approach was used to obtain a simulation model to predict the performance of an industrial rotating disc contactor (RDC) in the extraction of lubricating base oils by furfural. The field data of a lube‐oil producing plant was used to validate the model. This model can be used for the parametric study of the RDC column and to investigate the effect of operational data such as solvent and feed temperatures, solvent to feed ratio, and agitation rate on the yield of extraction and on the energy saving value of the extraction.

Results

The mathematical modeling of RDC shows good agreement with the plant data with an accuracy of 95% and the model was used to investigate the effect of adding a co‐solvent.

Conclusion

Results show that by using furfural with added 2,2,4 trimethylpentane it is possible to perform the extraction process at a lower process temperature, 363.15 K, compared with 393.15 K using furfural as solvent, and also at a lower 1.3 solvent/feed ratio, compared with 1.5 when furfural alone was used for as the solvent. This process modification leads to saving of 38% of the consumed energy per cubic meter of product in the extraction process.© 2012 Society of Chemical Industry
Biomechanics of Turtle Shells: How Whole Shells Fail in Compression
Authors: Magwene Paul M. , Socha John J.
Published: November 2012

Turtle shells are a form of armor that provides varying degrees of protection against predation. Although this function of the shell as armor is widely appreciated, the mechanical limits of protection and the modes of failure when subjected to breaking stresses have not been well explored. We studied the mechanical properties of whole shells and of isolated bony tissues and sutures in four species of turtles (Trachemys scripta, Malaclemys terrapin, Chrysemys picta, and Terrapene carolina) using a combination of structural and mechanical tests. Structural properties were evaluated by subjecting whole shells to compressive and point loads in order to quantify maximum load, work to failure, and relative shell deformations. The mechanical properties of bone and sutures from the plastral region of the shell were evaluated using three‐point bending experiments. Analysis of whole shell structural properties suggests that small shells undergo relatively greater deformations before failure than do large shells and similar amounts of energy are required to induce failure under both point and compressive loads. Location of failures occurred far more often at sulci than at sutures (representing the margins of the epidermal scutes and the underlying bones, respectively), suggesting that the small grooves in the bone created by the sulci introduce zones of weakness in the shell. Values for bending strength, ultimate bending strain, Young's modulus, and energy absorption, calculated from the three‐point bending data, indicate that sutures are relatively weaker than the surrounding bone, but are able to absorb similar amounts of energy due to higher ultimate strain values. J. Exp. Zool. 319A:86–98, 2012. © 2012 Wiley Periodicals, Inc.
Anteroposterior variation of the cell types in the interrenal gland of the male toad Rhinella arenarum (Amphibia, Anura)
Authors: Regueira Eleonora , Scaia María Florencia , Volonteri María Clara , Ceballos Nora Raquel
Published: November 2012

The interrenal gland of anurans synthesizes the steroids aldosterone and corticosterone, but it is unknown whether these hormones are synthesized by the same cell type. In this work, we aim to elucidate whether there are different steroidogenic cell types and whether they have specific regionalization in the interrenal gland of the male toad Rhinella arenarum. We characterized all cell types using histological, immuhistochemical, and histochemical methods as well as transmission electron microscopy. Furthermore, we evaluated the organization of the cell types in the gland and anteroposterior variations in the synthesis of the steroids. We found evidence of five cell types: two morphologically different steroidogenic cells, type 1: polyhedral cells tightly attached to each other that have spherical euchromatic nuclei and type 2: retracted cells loosely attached to each other that have oval heterochromatic nuclei. Cell type 2 is mainly observed in the inner zone of the gland. In addition, we observed two types of chromaffin cells, called type 3 and 4 cells, randomly distributed throughout the interrenal gland, as well as type 5 cells, recognized as summer cells. Morphometric analyses of the cell types in the anterior and posterior zones of the interrenal showed that the ratio “area of type 2 cells/total interrenal area” is significantly lower in the posterior zone. In vitro incubations showed that the posterior portion of the gland produces significantly higher amounts of both corticosterone and aldosterone. Overall, our results suggest that the type 2 cells are less active to synthesize both aldosterone and corticosterone, compared to type 1 cells. Unlike most previous reports on the interrenal gland of anurans, in R. arenarum there is a zonation of the steroidogenic cell types, which implies that the organ is not anteroposterior or dorsoventrally homogeneous. © J. Morphol., 2013. © 2012 Wiley Periodicals, Inc.
Chronic exposure of lung alveolar epithelial type II cells to tobacco‐specific carcinogen NNK results in malignant transformation: A new in vitro lung carcinogenesis model
Authors: Mennecier Gregory , Torres Luciana N. , Cogliati Bruno , Sanches Daniel S. , Mori Claudia M. , Latorre Andréia O. , Chaible Lucas M. , Mackowiak Ivone I. , Nagamine Marcia K. , Da Silva Tereza C. , Fukumasu Heidge , Dagli Maria Lucia Zaidan
Published: November 2012

Lung cancer is the leading cause of cancer‐related mortality in both men and women throughout the world. This disease is strongly associated with tobacco smoking. The aim of this manuscript was to establish an in vitro model that mimics the chronic exposures of alveolar epithelial type II cells to the tobacco‐specific nitrosamine carcinogen, NNK. Immortalized non‐neoplastic alveolar epithelial cells type II, (E10 cells), from BALB/c mice were exposed to low concentration of NNK (100 pM) during 5, 10, 15, and 20 cycles of 48 h. NNK‐transformed cells showed an increase of proliferation rate and motility. Moreover, these cells underwent epithelial‐to‐mesenchymal transition (EMT). Increased migratory capacity and EMT were correlated to the time of exposure to NNK. NNK‐transformed cells were tested for their growth and metastatic capacity in vivo. Subcutaneous injection of cells exposed to NNK for 20 cycles (E10‐NNK20 clone) into BALB/c mice led to the formation of subcutaneous tumors that arose after 40 ± 17 d in all animals, which died 95 ± 18 d after cell inoculation, with lymph nodes and lung metastasis. The morphological characteristics of tumors were compatible with metastatic undifferentiated carcinoma. Cells exposed to NNK for 5–10 cycles did not display metastatic capacity, while those exposed for 15 cycles displayed low capacity. Our results show that prolonged exposures to NNK led the cells to increasingly acquire malignant properties. The cellular model presented in this study is suitable for studying the molecular events involved in the different stages of malignant transformation. © 2012 Wiley Periodicals, Inc.
CORAL: Monte Carlo Method as a Tool for the Prediction of the Bioconcentration Factor of Industrial Pollutants
Authors: Toropova A. P. , Toropov A. A. , Martyanov S. E. , Benfenati E. , Gini G. , Leszczynska D. , Leszczynski J.
Published: November 2012

The CORAL software (http://www.insilico.eu/coral/) has been evaluated for application in QSAR modeling of the bioconcentration factor in fish (logBCF). The data used include 237 organic substances (industrial pollutants). Six random splits of the data into sub‐training (30–50 %), calibration (20–30 %), test (13–30 %), and validation sets (7–25 %) have been carried out. The following numbers display the average statistical characteristics of the models for the external validation set: correlation coefficient r2=0.880±0.017 and standard error of estimation s=0.559±0.131. The best models were obtained with a combined representation of the molecular structure by SMILES together with hydrogen suppressed graph.
PexLoc—Parallel excitation using local encoding magnetic fields with nonlinear and nonbijective spatial profiles
Authors: Haas M. , Ullmann P. , Schneider J. T. , Post H. , Ruhm W. , Hennig J. , Zaitsev M.
Published: November 2012

With the recent proposal of using magnetic fields that are nonlinear by design for spatial encoding, new flexibility has been introduced to MR imaging. The new degrees of freedom in shaping the spatially encoding magnetic fields (SEMs) can be used to locally adapt the imaging resolution to features of the imaged object, e.g., anatomical structures, to reduce peripheral nerve stimulation during in vivo experiments or to increase the gradient switching speed by reducing the inductance of the coils producing the SEMs and thus accelerate the imaging process. In this work, the potential of nonlinear and nonbijective SEMs for spatial encoding during transmission in multidimensional spatially selective excitation is explored. Methods for multidimensional spatially selective excitation radiofrequency pulse design based on nonlinear encoding fields are introduced, and it is shown how encoding ambiguities can be resolved using parallel transmission. In simulations and phantom experiments, the feasibility of selective excitation using nonlinear, nonbijective SEMs is demonstrated, and it is shown that the spatial resolution with which the target distribution of the transverse magnetization can be realized varies locally. Thus, the resolution of the target pattern can be increased in some regions compared with conventional linear encoding. Furthermore, experimental proof of principle of accelerated two‐dimensional spatially selective excitation using nonlinear SEMs is provided in this study. Magn Reson Med 70:1220–1228, 2013. © 2012 Wiley Periodicals, Inc.
Gene and cell‐mediated therapies for muscular dystrophy
Authors: Konieczny Patryk , Swiderski Kristy , Chamberlain Jeffrey S.
Published: November 2012

Duchenne muscular dystrophy (DMD) is a devastating muscle disorder that affects 1 in 3,500 boys. Despite years of research and considerable progress in understanding the molecular mechanism of the disease and advancement of therapeutic approaches, there is no cure for DMD. The current treatment options are limited to physiotherapy and corticosteroids, and although they provide a substantial improvement in affected children, they only slow the course of the disorder. On a more optimistic note, more recent approaches either significantly alleviate or eliminate muscular dystrophy in murine and canine models of DMD and importantly, many of them are being tested in early phase human clinical trials. This review summarizes advancements that have been made in viral and nonviral gene therapy as well as stem cell therapy for DMD with a focus on the replacement and repair of the affected dystrophin gene. Muscle Nerve 47: 649–663, 2013
Numerical modeling and optimization of wastewater treatment using porous polymeric membranes
Authors: Rezakazemi Mashallah , Ghafarinazari Ali , Shirazian Saeed , Khoshsima Ali
Published: November 2012

A new modeling approach was developed for prediction of ammonia removal from water by means of porous membranes. The model was based on adaptive neuro‐fuzzy interface system (ANFIS) to simulate ammonia stripping from water by means of hollow‐fiber membrane contactors. The predictions aimed to obtain optimum conditions for ammonia stripping using the Taguchi method. The initial concentrations of ammonia, pH of the ammonia solution, velocity of the feed, and the presence of excess ions in the ammonia feed solution were considered as the input properties. On the other hand, mass transfer coefficient was considered as output. The prediction results revealed that the pH of the ammonia feed has a significant effect on the separation of ammonia from water. The results also showed that the prediction of ANFIS model and experimental data match well and that the model can be used for prediction of porous membranes. Furthermore, simulated annealing was also used to determine controllable conditions to find the highest mass transfer coefficient. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Explicit and implicit multi‐center integrations
Authors: Koch Wolfhard H. G.
Published: November 2012

We present truncated expansions of multicenter one‐electron nuclear attraction and two‐electron repulsion integrals over localized basis functions in terms of one‐ and two‐center integrals of “Coulomb,” “exchange,” and “hybrid” type. Two variants are discussed: the “Explicit Multi‐center Integrations” and the “Implicit Multi‐Center Integrations” (abbreviated as “EMCI” and “IMCI”, respectively). While EMCI also deals with individual integrals, the IMCI option is the more appealing one: it enables us to evaluate the entire matrix elements of “Restricted Hartree–Fock”‐type in a very effective and chemically meaningful way. Due to the diatomic nature of our expansions, integrations over “Slater‐Type Orbitals” become well‐feasible, too. © 2012 Wiley Periodicals, Inc.
On the relation between surface roughness of metallic substrates and adhesion of human primary bone cells
Authors: Anselme K. , Bigerelle M.
Published: November 2012

Surface characteristics of materials, whether their topography, chemistry, or surface energy, play an essential part in osteoblast adhesion on biomaterials. Thus, the quality of cell adhesion will influence the cell's capacity to proliferate and differentiate in contact with a biomaterial. We have developed for more than ten years numerous studies on the influence of topography and chemistry of metallic substrates on the response of primary human bone cells. The originality of our approach is that contrary to most of other authors, we quantified the adhesion of primary human bone cells on metallic substrates with perfectly characterized surface topography after some hours but also over 21 days. Moreover, we have developed original statistical approaches for characterizing the relation between surface roughness and cell‐adhesion parameters. In this article, we will illustrate different studies we did these last ten years concerning the development of a new adhesion parameter, the adhesion power; the correlation between short‐term adhesion, long‐term adhesion, and proliferation; the influence of roughness organization on cell adhesion and the development of the order parameter; our modeling approach of cell adhesion on surface topography; the relative influence of surface chemistry and topography on cell adhesion and contact angle; the relation between surface features dimensions and cell adhesion. Further, some considerations will be given on the methods for scanning surface topography for cell‐adhesion studies. Finally, perspectives will be given to elucidate these intracellular mechanotransduction mechanisms induced by the deformation of cells on model sinusoidal peaks‐or‐valleys surfaces. SCANNING 36:11–20, 2014. © 2012 Wiley Periodicals, Inc.
Utility of improvised video‐camera collars for collecting contact data from white‐tailed deer: Possibilities in disease transmission studies
Authors: Lavelle Michael J. , Hygnstrom Scott E. , Hildreth Aaron M. , Campbell Tyler A. , Long David B. , Hewitt David G. , Beringer Jeff , VerCauteren Kurt C.
Published: November 2012

Rapidly evolving electronic technology enables wildlife researchers to collect previously unobtainable data. To explore possibilities of using deer‐borne cameras (DBCs) to collect behavioral data from an animal's point of view, we constructed DBCs and deployed them on 26 adult male white‐tailed deer (Odocoileus virginianus) within a closed population (405‐ha fenced area) in southern Texas just prior to the breeding season during autumn 2010. Our DBCs consisted of global positioning system collars with attached motion‐activated trail cameras. We obtained 21,474 video clips from 17 functional DBCs over a period of 14 days. Individual‐based data are invaluable in disease and population modeling; therefore, we confirmed the identify of 37 individual deer in field of view of DBCs based on ear tags, collar numbers, and antler characteristics (e.g., point counts, relative mass, tine length). Additionally, we recorded 85 contacts, including 36 with identifiable deer, involving breeding (n = 1), sparring (n = 63), grooming (n = 5), and muzzle contact (n = 16). Our results demonstrate the value of using DBCs to record direct contacts and associated behaviors and even to enable estimation of contact rates, thus improving the understanding of the potential for transmission of disease pathogens. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
Responses of white‐tailed deer and northern bobwhite food plants to a gradient of stand‐establishment intensities in pocosin pine plantations
Authors: Marsh Graham M. , Lane Vanessa R. , Miller Karl V. , Castleberry Steven B. , Miller Darren A. , Wigley T. Bently
Published: November 2012

Loblolly pine (Pinus taeda) plantations are established using various treatments to manage competing vegetation and increase pine production. Although young pine plantations historically supported early successional vegetation communities that contained abundant wildlife forage, increasing intensity of stand‐establishment treatments, particularly herbicides, has caused concern regarding potential effects on composition, availability, and quality of wildlife forage within young pine plantations. Few long‐term studies have described relationships between intensity of site preparation and effects on important forage plants for 2 economically and ecologically important game species: white‐tailed deer (Odocoileus virginianus) and northern bobwhite (Colinus virginianus). Therefore, we examined effects of 6 treatments of increasing stand‐establishment intensity via combinations of mechanical and chemical site preparation with herbaceous weed‐control on deer and bobwhite food plants from 1 year to 8 years after site preparation in loblolly pine plantations (n = 6) within pocosins in the Lower Coastal Plain of North Carolina, USA, during summers of 2002–2005, 2007–2009. Although woody and vine forage plants for deer and quail were common on all treatments, chemical site preparation resulted in long‐term decreases (approx. 50% for 8 yr) in coverage of these plants. Type of mechanical site preparation–spacing and herbaceous weed‐control had few effects on woody and herbaceous deer and quail food plants. Dissimilar from research in other regions, reduction in woody cover did not provide a concurrent increase in herbaceous food plants. Because of relatively poor forage quality in pocosin habitats, vegetation management practices may reduce deer and quail food quantity without increasing quality. However, because abundance of low‐quality forage is high in pocosin habitats, localized forage reductions due to site‐preparation techniques may not affect overall carrying capacity in these areas. © 2012 The Wildlife Society.
Evaluation of hair cortisol concentration as a biomarker of long‐term stress in free‐ranging polar bears
Authors: Macbeth Bryan J. , Cattet Marc R. L. , Obbard Martyn E. , Middel Kevin , Janz David M.
Published: November 2012

Long‐term physiological stress in individual animals may be an important mechanism linking ecological change with impaired wildlife population health. In the Southern Hudson Bay (SH) subpopulation of polar bears (Ursus maritimus), increasing stress associated with climate warming may be related to declining body condition. Accordingly, the development of tools to assess long‐term stress in this species may prove invaluable for conservation efforts in this threatened population. The measurement of hair cortisol concentration (HCC) has shown promise as a potential biomarker of long‐term stress in free‐ranging bears. However, to serve as a useful management tool, factors influencing HCC in polar bears must be identified and then revealed to establish linkages between environmental conditions and the fitness of individual animals. We determined HCC (median = 0.48 pg/mg [range = 0.16–2.26 pg/mg]) in 185 polar bears captured in southern Hudson Bay from 2007 to 2009. HCC was influenced by sex, family group status, and capture period but not by body region or hair type. Using models developed through a combination of hypothesis testing and information theory, we also determined that HCC was negatively associated with growth indices (length, mass, and body condition index) linked to fitness in polar bears. Additional research will be required across several polar bear populations to establish the utility of HCC as a tool for polar bear conservation. © 2012 The Wildlife Society.
On reversing the northern bobwhite population decline: 20 years later
Authors: Hernández Fidel , Brennan Leonard A. , DeMaso Stephen J. , Sands Joseph P. , Wester David B.
Published: November 2012

The northern bobwhite (Colinus virginianus) decline has become a cause célébre of wildlife conservation during the past 2 decades. With few exceptions, current broad‐scale population trends show ongoing erosion in bobwhite numbers across most of the species' range. The causes of these declines are ultimate factors exacerbated by certain proximate factors. Ultimate factors are centered on the loss and fragmentation of habitat. Proximate factors such as predation and disease also may be present. The impacts of some factors, such as climate change, remain unknown but may influence bobwhite population trajectories over the long term. Progress has occurred in bobwhite conservation efforts since 1990 and has culminated in the formation of the National Bobwhite Technical Committee and the publication of the Northern Bobwhite Conservation Initiative. The vast majority of prevailing agricultural, forestry, and to some extent rangeland land uses in the United States continue as threats to bobwhite population persistence in the foreseeable future. Land‐use patterns that once sustained widespread abundance of northern bobwhite during the early 20th century clearly are past and likely never to return. Landscape features that sustain and elevate northern bobwhite populations will only be maintained as a function of purposeful management actions directed at saving and creating usable space. © The Wildlife Society, 2012
Effects of landscape‐scale forest change on the range contraction of ruffed grouse in New York State, USA
Authors: Porter William F. , Jarzyna Marta A.
Published: November 2012

In New York State, USA, the abundance of ruffed grouse (Bonasa umbellus) has declined >75% since the 1960s. We hypothesized that range contraction of grouse in New York State was associated with broad‐scale spatial patterns relating to forest maturation and that these patterns would be evident at the landscape scale. We evaluated data available from New York Breeding Bird Atlases conducted in the early 1980s and again in the early 2000s, which included surveys of >5,000, 25‐km2 sample blocks across a landscape of 125,384 km2. We related detection and non‐detection of grouse within Breeding Bird Atlas blocks to forest amount, landscape configuration, and presence of neighboring grouse populations via autologistic regression. Loss of early successional forest was inversely related to the continued persistence of grouse (R2 = 0.61). Models showed that ruffed grouse were no longer detected in marginal areas of their distribution, blocks with low amounts of forest, and blocks with landscape configurations potentially advantageous to nest predators. We conclude that declines in both habitat quality and quantity have contributed to range contraction within New York State and that the factors affecting grouse populations have acted at broader spatial scales than are typically considered in habitat evaluation. Our work demonstrates that large landscape‐scale data sets are valuable in assessing changes in distribution and abundance of wildlife populations. Landscape analyses at large geographic scales (>100,000 km2) are of particular importance to managers because they represent ways of quantifying the influence of economic incentives and land‐use policy on habitats across large regions. © The Wildlife Society, 2012