bluuebunny/crossref_metadata_2025 huggingface dataset:
Mammalian target of rapamycin signaling is crucial for joint destruction in experimental arthritis and is activated in osteoclasts from patients with rheumatoid arthritis
Authors: Cejka Daniel , Hayer Silvia , Niederreiter Birgit , Sieghart Wolfgang , Fuereder Thorsten , Zwerina Jochen , Schett Georg
Published: April 2010

Objective

Activation of the mammalian target of rapamycin (mTOR) pathway is important for immune cell activation and bone metabolism. To date, the contribution of mTOR signaling to joint inflammation and structural bone and cartilage damage is unknown. The aim of this study was to investigate the potential of inhibiting mTOR as a treatment of inflammatory arthritis.

Methods

Human tumor necrosis factor–transgenic mice in which inflammatory arthritis was developing were treated with 2 different mTOR inhibitors, sirolimus or everolimus. The effects of treatment on clinical disease activity, inflammation, and localized joint and cartilage destruction were studied. In addition, the effects of mTOR inhibition on osteoclast survival and expression of key molecules of osteoclast function were analyzed in vitro. Moreover, synovial tissue from patients with rheumatoid arthritis (RA) was assessed for activation of the mTOR pathway.

Results

Inhibition of mTOR by sirolimus or everolimus reduced synovial osteoclast formation and protected against local bone erosions and cartilage loss. Clinical signs of arthritis improved after mTOR inhibition, and histologic evaluation showed a decrease in synovitis. In vitro, mTOR inhibition down‐regulated the expression of digestive enzymes and led to osteoclast apoptosis. Moreover, mTOR signaling was shown to be active in the synovial membrane of patients with RA, particularly in synovial osteoclasts.

Conclusion

Signaling through mTOR is an important link between synovitis and structural damage in inflammatory arthritis. Current pharmacologic inhibitors of mTOR could be effective in protecting joints against structural damage.
Heptahapticity in Binuclear (Cycloheptatrienyl)molybdenum Carbonyl Derivatives: The Interplay between Ring Hapticity/Planarity and Metal–Metal Multiple Bonding
Authors: Feng Xuejun , Xie Chanyuan , Xie Yaoming , King R. Bruce , Schaefer Henry F.
Published: April 2010

Theoretical studies on the binuclear (cycloheptatrienyl)molybdenum carbonyl complexes [(C7H7)2Mo2(CO)n] (n=6, 5, 4, 3, 2, 1, 0) indicate structures with fully bonded heptahapto η7‐C7H7 rings and four or fewer carbonyl groups to be energetically competitive. This is in striking contrast to the corresponding chromium derivatives. The lowest energy of such a structure for [(η7‐C7H7)2Mo2(CO)4] is a singlet unbridged structure with a formal MoMo single bond with a length of approximately 3.2 Å. A higher‐energy pentahapto structure [(η5‐C7H7)2Mo2(CO)4] is also predicted with a formal Mo≡Mo triple bond with a length of approximately 2.56 Å. Low‐energy structures are predicted for [(C7H7)2Mo2(CO)3] with two heptahapto η7‐C7H7 rings, either one or two bridging carbonyl groups, and formal MoMo double bonds with a length of approximately 2.8 Å. However, the global minimum for [(C7H7)2Mo2(CO)3] is a [(η7‐C7H7)(η5‐C7H7)Mo2(CO)3] structure with a formal Mo≡Mo triple bond with a length of approximately 2.53 Å. The lowest‐energy structures for [(C7H7)2Mo2(CO)2] and [(C7H7)2Mo2(CO)] have heptahapto η7‐C7H7 rings and predicted metal–metal bond lengths of approximately 2.54 and 2.31 Å, respectively, consistent with the formal triple and quadruple bonds, respectively, needed to give both metal atoms the favored 18‐electron configuration. The lowest‐energy structures for the carbonyl‐richer systems [(C7H7)2Mo2(CO)n] (n=6, 5) contain one trihapto η3‐C7H7 ring and one pentahapto η5‐C7H7 ring.
Ein einheitliches dreiaxiales Bruchkriterium für alle Betone
Authors: Speck Kerstin , Curbach Manfred
Published: April 2010

Die Auswertung zahlreicher mehraxialer Versuche hat ergeben, dass die auftretenden Versagensmechanismen unter mehraxialer Beanspruchung für alle Betonarten prinzipiell gleich sind. Dies gilt sowohl für Normal‐ bis ultrahochfesten Beton, für Leichtbeton als auch für Faserbeton. Das vorgestellte Bruchkriterium orientiert sich an diesen Versagensarten und wird über eine entsprechende Kalibrierung an das Verhalten des jeweiligen Betons angepasst. Im Zuge der Aktualisierung des CEB‐FIP Model Codes 90 wird es Einzug in die Bemessungsvorschriften finden.

A Unified Multiaxial Fracture Criterion for all Concretes

The evaluation of numerous multiaxial tests has shown that the occurring failure mechanisms under a multiaxial load are basically the same for all types of concrete. This is true for normal to ultra high performance concrete, lightweight concrete, as well as for fibre concrete. The presented fracture criterion is based on these failure types and is adjusted by a corresponding calibration to the behaviour of each concrete. In the course of the upgrade of the CEB‐FIP Model Code 90, it will find entry into the dimensioning specification.
Zum Durchstanzen von Flachdecken nach Eurocode 2
Authors: Hegger Josef , Walraven Joost C. , Häusler Frank
Published: April 2010

Die Regelungen zur Durchstanzbemessung im Eurocode 2 basieren im Wesentlichen auf den Modellvorstellungen in Model Code 90, der die Durchstanztragfähigkeit auf die Querkrafttragfähigkeit zurückführt. Nach Versuchsauswertungen ist diese Analogie für punktgestützte Platten jedoch nicht in jedem Fall zutreffend. Insbesondere für bügelbewehrte Platten ist bei der Bemessung nach Eurocode 2 ein Sicherheitsdefizit möglich, und es erscheint eine Anpassung der Bemessungsgleichungen zwingend erforderlich. Dieser Beitrag erläutert die Sicherheitsdefizite und schlägt verbesserte Bemessungsgleichungen vor.

Punching of Flat Slabs according to Eurocode 2

The punching shear provisions according to Eurocode 2 are based on the design recommendations in Model Code 90 where no differentiation between shear and punching shear design is made. This approach is not fully confirmed by test results for flat slabs. In particular for flat slabs with stirrups as shear reinforcement some design provisions according to Eurocode 2 do not achieve the required safety level. Therefore adjustments to the design equations seem to be necessary. In this paper the Eurocode 2 provisions are critically reviewed and improved design regulations are proposed.
Deep homology: A view from systematics
Authors: Scotland Robert W.
Published: April 2010

Over the past decade, it has been discovered that disparate aspects of morphology – often of distantly related groups of organisms – are regulated by the same genetic regulatory mechanisms. Those discoveries provide a new perspective on morphological evolutionary change. A conceptual framework for exploring these research findings is termed ‘deep homology’. A comparative framework for morphological relations of homology is provided that distinguishes analogy, homoplasy, plesiomorphy and synapomorphy. Four examples – three from plants and one from animals – demonstrate that homologous developmental mechanisms can regulate a range of morphological relations including analogy, homoplasy and examples of uncertain homology. Deep homology is part of a much wider range of phenomena in which biological (genes, regulatory mechanisms, morphological traits) and phylogenetic levels of homology can both be disassociated. Therefore, to understand homology, precise, comparative, independent statements of both biological and phylogenetic levels of homology are necessary.
Expression and purification of an antitumor‐analgesic peptide from the venom of Mesobuthus martensii Karsch by small ubiquitin–related modifier fusion in Escherichia coli
Authors: Cao Peng , Yu Jiemiao , Lu Wuguang , Cai Xueting , Wang Zhigang , Gu Zhenhua , Zhang Juan , Ye Tingmei , Wang Min
Published: April 2010

To prevent protein aggregation, some proteins are usually expressed as fusion proteins from which target proteins can be released by proteolytic or chemical reagents. In this report, small ubiquitin‐related modifier (SUMO) linked with a hexa‐histidine tag was used as a fusion partner for the antitumor‐analgesic peptide from the venom of Buthus martensii (Karsch) scorpion (AGAP). The optimal expression level of the soluble fusion protein, SUMO‐AGAP, was up to 40% of the total cellular protein. The fusion protein was purified by Ni‐NTA affinity chromatography and cleaved by a SUMO‐specific protease (Ulp1) to obtain the recombinant AGAP (rAGAP), which was further purified by Ni‐NTA affinity chromatography. The purified final product was >95% pure by SDS‐PAGE stained with Coomassie brilliant blue R‐250. Mass spectroscopic analysis indicated the protein to be 7142.63 Dalton, which equaled the theoretically expected mass. N‐terminal sequencing of rAGAP showed the sequence corresponded to the native protein. MTT assay indicated the rAGAP could significantly inhibit the proliferation of Jurkat and Hut 78 T lymphoma cell lines. The further writhing experiment showed that the rAGAP had an intensive analgesic effect. The expression strategy presented in this study allows convenient high yield and easy purification of the rAGAP with native sequences. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Food for thought: the effect of counterfactual thinking on the use of nutrition information
Authors: Aboulnasr Khaled , Sivaraman Anu
Published: April 2010

In three experiments, we examine the efficacy of counterfactual thinking (CFT) as a strategy to enhance consumers' motivation to process and use nutrition information on food packages. In the first study, we test whether CFT leads to greater motivation to process nutrition label information in the process of forming product attitudes. We also test whether motivation mediates the relationship between CFT and the influence of the nutrition label in product evaluation. In a second study, we test the effect of upward versus downward CFT on motivation. We also examine whether nutrition information on food packages moderates the relationship between CFT and product attitudes. In a third study, we examined the duration of the motivational effect of CFT. Results from the three studies support the role of CFT as a mechanism that enhances consumers' motivation to elaborate on and use nutrition information to form product attitudes. Copyright © 2010 John Wiley & Sons, Ltd.
Isotopic Oxygen Exchange over Pd/Al2O3 Catalyst: Study on C18O2 and 18O2 Exchange
Authors: Ojala Satu , Bion Nicolas , Rijo Gomes Sérgio , Keiski Riitta L. , Duprez Daniel
Published: April 2010

Oxygen mobility on Pd/Al2O3 catalysts is generally considered to be rather slow compared with other noble metal catalysts. This study shows that oxygen can be exchanged from gas‐phase CO2 produced during, for example, methane oxidation, more rapidly than from O2 molecules. The oxygen exchange from C18O2 occurs mainly on Al2O3, whereas 18O2 exchange needs to be carried out in the presence of palladium. However, the presence of Pd on Al2O3 slightly enhances C18O2 exchange according to the number of exchanged atoms in the gas phase. In this case, the calculation of initial rate for C18O2 exchange is not adequate to evaluate oxygen mobility; information on the number of exchanged atoms and on the evolution of the concentrations of the different isotopomers is also needed. The enhancement of oxygen exchange is due to carbonate formation on the catalytic surface, as evidenced by in situ FTIR spectroscopic measurements. A five‐step mechanism is suggested to explain these findings.
Molecular Logic Gates and Switches Based on 1,3,4‐Oxadiazoles Triggered by Metal Ions
Authors: Li Ai‐Fang , Ruan Yi‐Bin , Jiang Qian‐Qian , He Wen‐Bin , Jiang Yun‐Bao
Published: April 2010

Organic molecular devices for information processing applications are highly useful building blocks for constructing molecular‐level machines. The development of “intelligent” molecules capable of performing logic operations would enable molecular‐level devices and machines to be created. We designed a series of 2,5‐diaryl‐1,3,4‐oxadiazoles bearing a 2‐(para‐substituted)phenyl and a 5‐(o‐pyridyl) group (substituent X=NMe2, OEt, Me, H, and Cl; 1 a–e) that form a bidentate chelating environment for metal ions. These compounds showed fluorescence response profiles varying in both emission intensity and wavelength toward the tested metal ions Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, and Pb2+ and the responses were dependent on the substituent X, with those of 1 d being the most substantial. The 1,3,4‐oxadiazole O or N atom and pyridine N atom were identified as metal‐chelating sites. The fluorescence responses of 1 d upon metal chelation were employed for developing truth tables for OR, NOR, INHIBIT, and EnNOR logic gates as well as “ON‐OFF‐ON” and “OFF‐ON‐OFF” fluorescent switches in a single 1,3,4‐oxadiazole molecular system.
Thiotimolin – Ein Nanoreview
Authors: Schneider Thomas
Published: April 2010

Mit seinen drei berühmten Beiträgen über Thiotimolin, die er zwischen 1948 und 1960 veröffentlichte, gilt Isaac Asimov als Begründer der Chronochemie. Dieser Review gibt einen Überblick über die wichtigsten Eigenschaften und die bisher bekannten Verwendungsmöglichkeiten der ungewöhnlichen Substanz.
Litz wire radiofrequency receive coils for hyperpolarized noble gas MR imaging of rodent lungs at 73.5 mT
Authors: Dominguez‐Viqueira William , Berger Warren , Parra‐Robles Juan , Santyr Giles E.
Published: April 2010

Magnetic resonance imaging with hyperpolarized noble gases, 3He or 129Xe, has become a promising approach for visualizing lung anatomy and function. The polarization of hyperpolarized noble gases does not depend on the magnetic field strength of the imaging system providing an opportunity to image at magnetic field strengths considerably lower than those typically used for clinical purposes (<0.1 T). At such low fields, image noise is dominated by electronic sources, particularly those originating from the radiofrequency coils. An improvement in image signal‐to‐noise ratio (SNR) is possible at low fields by reducing radiofrequency coil noise using Litz wire. In this work, radiofrequency coils of similar geometry were constructed with either conventional copper wire or three different types of Litz wire and compared in phantoms and in vivo in rat lungs using hyperpolarized 3He and 129Xe gases. The coils were tuned at either 0.866 MHz or 2.385 MHz, corresponding to the Larmor frequencies of 129Xe and 3He at 73.5 mT. The effect of wire spacing and number of windings was investigated. A SNR improvement of up to 131% was obtained with the Litz wire when compared with that of conventional copper wire. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 37B: 75–85, 2010
A high temperature superconducting imaging coil for low‐field MRI
Authors: Cheong Hoon‐Sin , Wild James , Alford Neil , Valkov Ivelin , Randell Christopher , Paley Martyn
Published: April 2010

In low field MRI (<0.5T), the signal‐to‐noise ratio (SNR) is predominantly degraded by thermal noise due to the electrical resistance of the imaging coil. This means using an imaging coil made of materials with a low intrinsic resistivity such as high temperature superconductors (HTS) should improve the SNR significantly when compared to an equivalent copper coil. The aim of this study was to perform a quantitative analysis on the performance of a cryogenically‐cooled HTS coil in low field MRI. A 70 mm circular spiral HTS resonator was fabricated by using YBa2Cu3O7 (YBCO) onto a sapphire substrate. The HTS coil was placed inside a cryogenic Dewar flask made of G10 materials to allow cooling using liquid nitrogen. A copper coil with the same layout was also fabricated to provide reference data for SNR comparisons. From the quality factor (Q) measurement results, the cryogenically‐cooled HTS coil was estimated to give SNR gains of 4.0 and 1.9 when compared to the copper coil at room temperature (292 K) and at the same cryogenic temperature (81.5 K) respectively. The phantom imaging results showed good agreement with these estimations in which SNR gains of 3.7 and 1.8 were recorded for the same comparisons. Similar SNR gains of 3.2 and 1.8 were also measured from in‐vivo hand imaging results, confirming the advantage of HTS coils over equivalent copper coils in low field MRI. Meanwhile, the SNR gain of the HTS coil against the room temperature copper coil dropped to 1.8 when the coil‐to‐sample separation in the latter setup was minimized to around 1 mm. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 37B: 56–64, 2010
Haptic interaction of organs based on the spherical harmonic representation
Authors: Yang Zhengyi , Vegh Viktor , Tieng Quang M. , Olsen‐Kettle Louise M. , Wang Deming
Published: April 2010

Visual and haptic organ interactions in real time are essential in virtual reality–based medical simulations to provide training, early diagnosis, and improved treatment planning. This work presents a robust method of computing the deformation of an elastic object when external forces are applied. Point‐based haptic interaction between the user of the haptic device and an object is outlined and is formulated as a deformation problem over the surface. The model is expressed in the spherical harmonic basis, from which both haptic device force feedback and object surface updates are calculated. Haptic and visual updates are performed in the same basis, in turn providing significant benefits of computing efficiency and multiresolution modeling. Partially, this is due to the fact that in the model the objects are represented as surfaces. A haptic device is used to probe different prostates that have been segmented and reconstructed from MR images to validate the findings. The calculated deformation and feedback force is further validated against the established finite element method. © 2010 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 37B: 45–55, 2010
Clinical significance of the 21‐gene signature (Oncotype DX) in hormone receptor‐positive early stage primary breast cancer in the Japanese population
Authors: Toi Masakazu , Iwata Hiroji , Yamanaka Takeharu , Masuda Norikazu , Ohno Shinji , Nakamura Seigo , Nakayama Takahiro , Kashiwaba Masahiro , Kamigaki Shunji , Kuroi Katsumasa
Published: April 2010

BACKGROUND:

The 21‐gene signature has been intensively studied and incorporated into major guidelines for treatment decision in early breast caner. However, it remains to be examined whether this system is applicable to Asian populations.

METHODS:

The authors collected 325 tumor tissues from estrogen receptor (ER)‐positive primary breast cancer patients who had undergone surgery and were treated with tamoxifen between 1992 and 1998. The tissues were analyzed for the 21‐gene signature, and the patients were classified into groups of low, intermediate, or high risk based on the Recurrence Score.

RESULTS:

A total of 280 patients were eligible, with adequate reverse transcription polymerase chain reaction profiles for the Recurrence Score. Of those, 200 and 80 patients had lymph node‐negative and lymph node‐positive disease, respectively. The proportions of lymph node‐negative patients categorized as being at low, intermediate, or high risk were 48%, 20%, and 33%, respectively. In lymph node‐negative patients, the Kaplan‐Meier estimates of the distant recurrence rate at 10 years were 3.3% (95% confidence interval [95% CI], 1.1‐10.0%), 0%, and 24.8% (95% CI, 15.7‐37.8%) for those in the low‐risk, intermediate‐risk, and high‐risk groups, respectively. The risk of distant recurrence in the low‐risk group was significantly lower than that in the high‐risk group when the entire Kaplan‐Meier plots were compared (P < .001, log‐rank test). There was a significant difference for overall survival between the low‐risk and the high‐risk groups (P = .008, log‐rank test).

CONCLUSIONS:

This is the first report to show that the 21‐gene signature has value in providing prognostic information in Asian populations with ER‐positive, lymph node‐negative breast cancer. Cancer 2010. © 2010 American Cancer Society.
Quality meshing based on STL triangulations for biomedical simulations
Authors: Marchandise E. , Compère G. , Willemet M. , Bricteux G. , Geuzaine C. , Remacle J.‐F.
Published: April 2010

This work describes an automatic approach to recover a high‐quality surface mesh from low‐quality or oversampled inputs (STL‐files) obtained from medical imaging through classical segmentation techniques. The approach combines a robust method of parametrization based on harmonic maps (Int. J. Numer. Meth. Engng. 2009; accepted) with a recursive call to a multi‐level edge partitioning software. By doing so, we are able to get rid of the topological and the geometrical limitations of harmonic maps. The overall remeshing procedure is implemented, together with the finite element discretization procedure required for computing harmonic maps, in the open‐source mesh generator Gmsh (Int. J. Numer. Meth. Engng. 2009; 79(11):1309–1331). We show that the proposed method produces high‐quality meshes and we highlight the benefits of using those high‐quality meshes for biomedical simulations. Copyright © 2010 John Wiley & Sons, Ltd.
Linear Dichroism in the XANES of Partially Oriented Samples: Theory and Application to the Photosynthetic Manganese Complex
Authors: Liebisch Peter , Dau Holger
Published: April 2010

For molecular systems which are partially ordered with respect to one macroscopic axis, for example, the sample–surface normal, X‐ray absorption spectroscopy (XAS) with linearly polarized synchrotron radiation can provide information on structure and orientation of the X‐ray absorbing site (polarized or linear‐dichroism XAS). Examples for such partially oriented systems are protein‐carrying membrane particles deposited in the form of multilayers on surfaces, layered minerals, surface films or imperfect 2D crystals, planar electrodes or catalytic surfaces. For electric dipole transitions, equations are derived describing how partial unidirectional orientation determines the linear dichroism (LD). The approach presented facilitates description of 1) LD in multiple‐scattering contributions of the extended X‐ray absorption fine‐structure (EXAFS) and 2) of LD in the X‐ray absorption near‐edge structure (LD‐XANES). Structural and orientation information becomes accessible by combination with ab initio XANES calculations. The LD‐XANES approach is applied to the water‐oxidizing Mn complex of photosystem II. The results suggest that the (μ‐O)‐(μ‐O) vectors of the Mn‐(μ‐O)2‐Mn units are at an average angle to the membrane normal of 30–45°. The best‐fit structure in connection with crystallographic data suggests a specific oxidation‐state assignment: Mn(1)IIIMn(2)IIIMn(3)IVMn(4)IV. However, currently this assignment remains uncertain. In future studies, the LD‐XANES analysis should play an important role in construction of unequivocal atomic‐resolution model of the photosynthetic Mn complex.
Prediction of Local pH Variations during Amperometric Monitoring of Vesicular Exocytotic Events at Chromaffin Cells
Authors: Amatore Christian , Arbault Stéphane , Bouret Yann , Guille Manon , Lemaître Frédéric
Published: April 2010

Electrochemical monitoring of the exocytosis process is generally performed through amperometric oxidation of the electroactive messengers released by single living cells. Herein, we consider the vesicular release of catecholamines by chromaffin cells. Each exocytotic event is thus detected as a current spike whose morphology (intensity, duration, area, etc.) features the efficiency of the secretion process. However, the electrochemical oxidation of catechols produces quinone derivatives and protons. As a consequence, unless specific mechanisms may be adopted by a cell to regulate the pH near its membrane, the local pH between the cell membrane and the electrode necessarily drops within the electrode–cell cleft. Though this consequence of amperometric detection is generally ignored, it has been investigated in this work through simulation of the local pH drop created during the amperometric recording of a sequence of exocytotic events. This was performed based on frequencies and magnitudes of release detected at chromaffin cells. The corresponding acidification was shown to severely depend on the microelectrode radius. For usual 10 μm diameter carbon fiber electrodes, pH values below six were predicted to be reached within the electrode–cell cleft after monitoring a few current spikes.
Si modified Ge10 cluster: the preparation and characterization of single crystal Na4(Ge,Si)9O20
Authors: Xiao Peng‐Yan , Ren Tie‐Zhen , Wang Zhi‐Qiang , Christensen K. E.
Published: April 2010

A Si modified Ge10 cluster with structure Na4(Ge,Si)9O20 (denoted as HUT‐1) was synthesized by hydrothermal synthesis at 160 °C with a sodium silicate source. The compound was characterized by single crystal, powder X‐ray diffraction and TGA‐DSC analysis. HUT‐1 crystallizes in space group I41 (80) with calculated unit cell (a=14.966(5) Å, c=7.343(2) Å, V=1644.8(9) Å3), which has the same structure as Na4Ge9O20. HUT‐1 has a high Si/Ge ratio with an approximate formula of Na4Ge7.68Si1.32O20. Single crystal X‐ray structure refinements together with results from X‐ray powder diffraction (XRPD) confirm the occupancy of Si at two tetrahedral sites. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Three‐dimensional study of the pressure field and advantages of hemispherical crucible in silicon Czochralski crystal growth
Authors: Mokhtari F. , Bouabdallah A. , Merah A. , Zizi M. , Hanchi S. , Alemany A.
Published: April 2010

The effects of several growth parameters in cylindrical and spherical Czochralski crystal process are studied numerically and particularly, we focus on the influence of the pressure field. We present a set of three‐dimensional computational simulations using the finite volume package Fluent in two different geometries, a new geometry as cylindro‐spherical and the traditional configuration as cylindro‐cylindrical. We found that the evolution of pressure which is has not been studied before; this important function is strongly related to the vorticity in the bulk flow, the free surface and the growth interface. It seems that the pressure is more sensitive to the breaking of symmetry than the other properties that characterize the crystal growth as temperature or velocity fields. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization and growth of CdS nanoparticles by a cost effective chemical reduction method
Authors: Bhattacharya R. , Manna A. , Das T. K. , Saha S.
Published: April 2010

A simple chemical reduction method is followed to grow CdS nanoparticles at room temperature with different duration of time. The grown samples are ultrasonicated in ethanol. The dispersed samples are characterized using electron diffraction techniques. Simultaneously optical absorption, photoluminescence and longtime photorelaxation of these samples are studied at room temperature. An increase in band gap is observed in each case as compared to bulk CdS. Also particle size increases with increase of growth time and hence there is decrease of band gap with increase of growth duration. Simultaneously long time relaxation increases with increase of growth time. An attempt is made to correlate the structural, optical, electrical and opto‐electrical properties. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, characterization and dielectric properties of EuBa2SbO6 nanocrystals
Authors: Kavitha V. T. , Vijayakumar C. , Wariar P. R. S. , Koshy J.
Published: April 2010

Nanoparticles of EuBa2SbO6, a complex perovskite metal oxide were synthesized by a self‐sustained combustion method employing citric acid as the complexing agent. The powders were characterized by X‐ray diffraction, IR and Raman spectroscopy, transmission electron microscopy and scanning electron microscopy. Nanocrystals of EuBa2SbO6 were sintered to 97 % of theoretical density at 1450 °C for 4 h without any sintering aid. The dielectric properties (dielectric constant, εr and loss factor, tanδ) of the ceramics have been measured in the frequency range 50 Hz to 5 MHz at room temperature. The chemical non‐reactivity of EuBa2SbO6 with YBa2Cu3O7‐δ makes it an ideal substrate for YBa2Cu3O7‐δ superconductors. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Addition to the theory of LPE growth: Crystallization mechanisms
Authors: Peev N. S.
Published: April 2010

Different possible mechanisms of crystal growth for the used in the practice LPE techniques are considered in the present paper. The time dependences of the super saturation for the cases of normal growth mechanism and screw dislocations growth mechanism are presented. The values of the stationary super saturation, of the stationary growth rate and of the time constant for the transient growth process are obtained. The effect of the initial super saturation on the growth rate is considered. Relation between the stationary value of the super saturation, the time constant of the transient process, the cooling rate and the liquidus surface slope has been ascertained. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Methyltrioxorhenium Catalysis in Nonconventional Solvents: A Great Catalyst in a Safe Reaction Medium
Authors: Crucianelli Marcello , Saladino Raffaele , De Angelis Francesco
Published: April 2010

The requirement that chemical processes are sustainabable, reflected in waste reduction and the use of safe reagents and reaction conditions, is becoming even more stringent as a result of pressure by society and governments to preserve the environment and protect human health. Catalysis offers numerous benefits related to green chemistry, including lowered energetic reaction requirements; catalytic, rather than stoichiometric, amounts of materials; increased selectivity; lowered consumption of processing and separation agents; and, in many cases, the use of less‐toxic compounds. Our research group has for a long time been studying methyltrioxorhenium in the oxyfunctionalization of different substrates, by using H2O2 or its urea‐hydrogen peroxide complex as the primary oxidant. In this Review paper we aim to provide a full literature account on the catalytic activity and selectivity of methyltrioxorhenium in the oxyfunctionalization reaction, either in nonconventional solvents or under solvent‐free conditions, with a particular emphasis on the use of ionic liquids as green reaction media.
The checkpoint kinase ATM protects against stress‐induced elevation of cyclin D1 and potential cell death in neurons
Authors: Hitomi Masahiro , Stacey Dennis W.
Published: April 2010

Quantitative cytometric studies show that cyclin D1 levels must decline during S phase for proper cell cycle progression, and that cyclin D1 decline follows phosphorylation induced by the checkpoint kinases ataxia telangiectasia mutated (ATM) and ATM and Rad3‐related (ATR). ATM is mutated in ataxia telangiectasia (AT), a disease characterized by progressive neurodegeneration. Importantly, neurodegeneration in many cases has been linked to the increased expression of cyclin D1 in neurons leading to inappropriate cell cycle entry. These facts prompted us to test the possibility that ATM normally protects against neural degeneration by suppressing cyclin D1 levels, particularly following genotoxic stress. For this purpose, neural stem cells were induced to differentiate into mature neural cells, including neurons. ATM activity in these cultures was inhibited with a specific chemical inhibitor in the presence or absence of hydrogen peroxide treatment, and the effect on cyclin D1 expression was determined by quantitative, single cell cytometric analyses. As predicted, inhibition of ATM did promote elevation of cyclin D1 in differentiated neurons, particularly under conditions of oxidative stress. The survival of differentiated neurons and of neural stem cells was reduced by such treatments. These data support our suggestion that ATM functions to maintain low levels of cyclin D1 expression in differentiated neurons; and may provide important clues in understanding neural degeneration in general. © 2010 International Society for Advancement of Cytometry
Temporal and spatial expression of CCN genes in zebrafish
Authors: Fernando Carol A. , Conrad Patricia A. , Bartels Cynthia F. , Marques Tomas , To Michael , Balow Stephanie A. , Nakamura Yukio , Warman Matthew L.
Published: April 2010

The six mammalian CCN genes (Cyr61, CTGF, Nov, WISP1, WISP2, WISP3) encode a family of secreted, cysteine‐rich, multimodular proteins having roles in cell proliferation, adhesion, migration, and differentiation during embryogenesis, wound healing, and angiogenesis. We used bioinformatics to identify 9 CCN genes in zebrafish (zCCNs), 6 of which have not been previously described. When compared with mammalian CCN family members, 3 were paralogs of Cyr61, 2 of CTGF, 2 of WISP1, 1 of WISP2, and 1 of WISP3. No paralog of Nov was found. In situ hybridization was performed to characterize the sites of expression of the zCCNs during early zebrafish development. zCCNs demonstrated both unique and overlapping patterns of expression, suggesting potential division of labor between orthologous genes and providing an alternate approach to gene function studies that will complement studies in mammalian models. Developmental Dynamics 239:1755–1767, 2010. © 2010 Wiley‐Liss, Inc.
Staying alive: Dalmatian mediated blocking of apoptosis is essential for tissue maintenance
Authors: Kerman Bilal E. , Andrew Deborah J.
Published: April 2010

In an EMS screen for mutations disrupting tracheal development, we identified new alleles of the dalmation (dmt) gene, which had previously been shown to affect peripheral nervous system (PNS) development. Here, we demonstrate that dmt loss results in programmed cell death, disrupting PNS patterning and leading to large gaps in the salivary duct and trachea. Dmt loss results in increased expression of the proapoptotic regulator genes head involution defective (hid) and reaper (rpr), and deletion of these genes or tissue‐specific expression of the baculoviral apoptotic inhibitor P35 rescues the dmt defects. dmt is also required to protect cells from irradiation induced expression of hid and rpr during the irradiation resistant stage, which begins as cells become irreversibly committed to their final fates. Thus, we propose that Dmt keeps cells alive by blocking activation of hid and rpr as cells become irreversibly committed. Developmental Dynamics 239:1609–1621, 2010. © 2010 Wiley‐Liss, Inc.
Prickle1b mediates interpretation of migratory cues during zebrafish facial branchiomotor neuron migration
Authors: Mapp Oni M. , Wanner Sarah J. , Rohrschneider Monica R. , Prince Victoria E.
Published: April 2010

The facial branchiomotor neurons undergo a characteristic tangential migration in the vertebrate hindbrain. Several signaling mechanisms have been implicated in this process, including the non‐canonical Wnt/planar cell polarity (PCP) pathway. However, the role of this signaling pathway in controlling the dynamics of these neurons is unclear. Here, we describe the cellular dynamics of the facial neurons as they migrate, focusing on the speed and direction of migration, extension of protrusions, cell shape, and orientation. Furthermore, we show that the PET/LIM domain protein Prickle1b (Pk1b) is required for several aspects of these migratory behaviors, including cell orientation. However, we find that centrosome localization is not significantly affected by disruption of Pk1b function, suggesting that polarization of the neurons is not completely lost. Together, our data suggest that Pk1b function may be required to integrate the multiple migratory cues received by the neurons into polarization instructions for proper posterior movement. Developmental Dynamics 239:1596–1608, 2010. © 2010 Wiley‐Liss, Inc.
Embryonic and not maternal trisomy causes developmental attenuation in the Ts65Dn mouse model for Down syndrome
Authors: Blazek Joshua D. , Billingsley Cherie N. , Newbauer Abby , Roper Randall J.
Published: April 2010

Trisomy 21 results in Down syndrome (DS) and causes phenotypes that may result from alterations of developmental processes. The Ts65Dn mouse is the most widely used genetic and phenotypic model for DS. We used over 1,500 offspring from Ts65Dn and two nontrisomic genetically similar control strains to investigate the influence of trisomy on developmental alterations and number of offspring. For the first time, we demonstrate gross developmental attenuation of Ts65Dn trisomic offspring at embryonic day (E) 9.5 and E13.5 and show that the major determinant of the developmental changes is segmental trisomy of the embryo and not the trisomic maternal uterine environment. Maternal alleles of nontrisomic genes linked to Pde6b may also influence the development of Ts65Dn offspring. Both developmental attenuation and the contribution of trisomic and nontrisomic genes are important components in the genesis of DS phenotypes. Developmental Dynamics 239:1645–1653, 2010. © 2010 Wiley‐Liss, Inc.
Natural killer cells become tolerogenic after interaction with apoptotic cells
Authors: Chong Wai Po , Zhou Jianfang , Law Helen K. W. , Tu Wenwei , Lau Yu Lung
Published: April 2010

NK cells are effectors in innate immunity and also participate in immunoregulation through the release of TGF‐β1 and lysis of activated/autoreactive T cells. Apoptotic cells (AC) have been shown to induce tolerogenic properties in innate immune cells, including macrophages and dendritic cells, but not NK cells. In this study, we demonstrated that after interaction with AC, NK cells released TGF‐β1, which in turn suppressed the production of IFN‐γ by NK cells upon IL‐12 and IgG activation. We further identified phosphatidylserine as a potential target on AC for the NK cells, as phosphatidylserine could stimulate NK cells to release TGF‐β1, which in turn suppressed CD4+ T‐cell proliferation and activation. Moreover, AC‐treated NK cells displayed cytotoxicity against autologous‐activated CD4+ T cells by upregulating NKp46. This lysis occurred in part through the NKp46‐vimentin pathway, as activated CD4+ T cells expressed vimentin on the cell surface and blocking of vimentin or NKp46, but not other NK‐cell receptors, significantly suppressed the NK‐cell cytotoxicity. We report here a novel interaction between NK cells and AC, resulting in the tolerogenic properties of NK cells required for immune contraction.
Differential subcellular localization of the regulatory T‐cell protein LAG‐3 and the coreceptor CD4
Authors: Woo Seng‐Ryong , Li Nianyu , Bruno Tullia C. , Forbes Karen , Brown Scott , Workman Creg , Drake Charles G. , Vignali Dario A. A.
Published: April 2010

CD4 binds to MHC class II molecules and enhances T‐cell activation. The CD4‐related transmembrane protein LAG‐3 (lymphocyte activation gene‐3, CD223) binds to the same ligand but inhibits T‐cell proliferation. We have previously shown that LAG‐3 cell surface expression is tightly regulated by extracellular cleavage in order to regulate its potent inhibitory activity. Given this observation and the contrasting functions of CD4 and LAG‐3, we investigated the cell distribution, location and transport of these related cell surface molecules. As expected, the vast majority of CD4 is expressed at the cell surface with minimal intracellular localization, as determined by flow cytometry, immunoblotting and confocal microscopy. In contrast, nearly half the cellular content of LAG‐3 is retained in intracellular compartments. This significant intracellular storage of LAG‐3 appears to facilitate its rapid translocation to the cell surface following T‐cell activation, which was much faster for LAG‐3 than CD4. Increased vesicular pH inhibited translocation of both CD4 and LAG‐3 to the plasma membrane. While some colocalization of the microtubule organizing center, early/recycling endosomes and secretory lysosomes was observed with CD4, significantly greater colocalization was observed with LAG‐3. Analysis of CD4:LAG‐3 chimeras suggested that multiple domains may contribute to intracellular retention of LAG‐3. Thus, in contrast with CD4, the substantial intracellular storage of LAG‐3 and its close association with the microtubule organizing center and recycling endosomes may facilitate its rapid translocation to the cell surface during T‐cell activation and help to mitigate T‐cell activation.
New Mixed‐Valence MnII/III6 Complexes Bearing Oximato and Azido Ligands: Synthesis, and Structural and Magnetic Characterization
Authors: Lampropoulos Christos , Stamatatos Theocharis C. , Manos Manolis J. , Tasiopoulos Anastasios J. , Abboud Khalil A. , Christou George
Published: April 2010

The combined use of the anion of methyl 2‐pyridyl ketone oxime (mpko–) and azides (N3–) in non‐carboxylate Mn chemistry has afforded two new Mn6 clusters, [Mn6O3(N3)3(mpko)6(H2O)3](ClO4)2 (1) and [Mn6O3(N3)5(mpko)6(H2O)] (2), which are mixed‐valence (MnII, 5 MnIII). The 1:1:1:1 reaction of Mn(ClO4)2·6H2O, mpkoH, NaN3 and NEt3 in MeOH gave the cationic complex 1, while a similar reaction using additional NaO2CMe led instead to the neutral complex 2. The structurally unprecedented cores of the two cages are very similar, and contain the six Mn ions in a topology comprising three vertex‐sharing oxide‐centered triangles bridged by two end‐on azides. Variable‐temperature, solid‐state dc and ac magnetization studies were carried out for 1 and 2 in the 1.8–300 K range. The data reveal S = 5/2 ground states for both complexes, and fitting of magnetization vs. field (H) and temperature (T) data by matrix diagonalization for 1 gave S = 5/2, D = –1.4(3) cm–1, and g = 1.99(1), where D is the axial zero‐field splitting (ZFS) parameter. The combined results demonstrate the versatility of 2‐pyridyl ketone oxime anions in the presence of suitable ancillary ligands, such as azides, for the synthesis of new Mn clusters, without requiring the co‐presence of carboxylate ligands.
Indium‐Promoted Allylation Reaction of Imino‐Isatins in Aqueous Media: Synthesis of Quaternary 3‐Aminooxindoles
Authors: Alcaide Benito , Almendros Pedro , Aragoncillo Cristina
Published: April 2010

Quaternary 3‐amino‐2‐oxindoles have been obtained viaallylation and propargylation reactions of imino‐isatins in aqueous media promoted by In and Zn respectively, under Barbier conditions, in good to excellent yields. A quaternary new stereocenter has been formed without hydrolysis of the starting imino‐isatin.
Ultrasound‐guided mechanical fragmentation of sialoliths (sonoguide forceps)
Authors: Geisthoff Urban W. , Maune Steffen
Published: April 2010

Background

Little data about the efficacy and limitations of ultrasound‐guided mechanical intraductal stone fragmentation and removal of sialoliths (Sonoguide Forceps) exist.

Methods

This was a chart review of patients treated within the last 4 years at 2 tertiary care centers.

Results

Sonoguide Forceps were used as a second‐line treatment in 22 patients with sialolithiasis. Ten patients were free of stones and symptoms afterwards (7 of 17 submandibular, 2 of 4 parotid, 1 of 1 sublingual). Six patients were primarily treated for parotid sialolithiasis, 4 with successful stone retrieval. The reasons for failure were a lack of accessibility to the stone by the forceps (n = 9), the impossibility of grasping the stone (n = 5), and/or the concomitant grabbing of soft tissue together with the stone (n = 3).

Conclusion

The efficacy of Sonoguide Forceps as both a secondary and primary treatment modality makes it an interesting, simple, and inexpensive therapeutic alternative. Relevant parameters for treatment success include the size and position of the stones. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Evaluation of lymphangiogenesis in premalignant conditions of the head and neck mucosa
Authors: Palomba Annarita , Gallo Oreste , Brahimi Arta , Franchi Alessandro
Published: April 2010

Background

Our aim was to determine whether lymphangiogenesis occurs in the early steps of cancerogenesis of the upper aerodigestive tract.

Methods

We assessed the number of lymphatics per unit area (lymphatic vascular density [LVD]) and the percent area occupied by the lymphatic vessels (lymphatic vascular area [LVA]) by computer‐assisted morphometric analysis in 56 samples immunohistochemically stained with the lymphatic marker D2‐40. The results were compared to those obtained in 63 invasive squamous cell carcinomas.

Results

No significant difference was observed between normal mucosa, hyperplasia/mild dysplasia, and moderate/severe dysplasia for LVD (p = .8) and LVA (p = .7). Conversely, invasive carcinomas presented a higher LVD than normal mucosa and precancerous lesions (p < .001), whereas there was no difference for LVA (p = .1).

Conclusion

Lymphangiogenesis does not occur in premalignant lesions of the upper aerodigestive tract and it is rather a late event associated with the development of an invasive phenotype. © 2010 Wiley Periodicals, Inc. Head Neck, 2010
Visualizing meltwater flow through snow at the centimetre‐to‐metre scale using a snow guillotine
Authors: Williams Mark W. , Erickson Tyler A. , Petrzelka Jennifer L.
Published: April 2010

Movement of liquid water through snowpacks remains one of the least understood aspects of snow hydrology. Liquid water movement through snowpacks is generally recognized to occur in distinct flow paths rather than as uniform flow through a homogeneous porous medium. Dye tracer experiments have been used in studies of meltwater flow through snow since the 1930s. Although dye tracer experiments have provided valuable qualitative information about meltwater pathways, quantitative descriptions of their spacing and location are not commonly available because of the difficulty in precisely excavating and measuring pathways. Here we provide a new proof‐of‐concept instrument we term a ‘snow guillotine’ that provides more quantitative information from dye tracer experiments conducted on melting snowpacks. Photographs are taken of each cross‐section over a 1‐m distance. Application of image processing and geostatistical analysis allows collection of high‐resolution (1 cm3), three‐dimensional data on meltwater flow through a snowpack.

The results show preferential flowpaths, with the majority of vertical flow occurring in the upper 20–55 cm of the snowpack, while fewer preferential flowpaths are apparent below 100 cm. The number of vertical flowpaths in the upper half of the snowpack averaged almost 100 per m2, with the highest number of flowpaths reaching almost 300 per m2. Layer interfaces were found to significantly increase the volume of dye, indicating dominance by lateral flow at these boundaries. At each stratigraphic interface, the number of individual clusters decreased and it was more likely for a dyed pixel to be part of a large cluster. Geostatistical analyses showed that there were large increases in correlation lengths and the connectivity function at stratigraphic layers in contrast to low values between layers. For example, the buried ice layer in Experiment A at 169–170 cm showed separation distances of 20 cm. In contrast, two rows above this layer the separation distance was only 2 cm. Implementation of the snow guillotine provides the ability to conduct geostatistical analyses on field measurements of meltwater flow while providing three‐dimensional, quantitative data of unprecedented spatial resolution. Copyright © 2010 John Wiley & Sons, Ltd.