bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of powder‐to‐liquid monomer ratio on properties of an injectable iodine‐containing acrylic bone cement for vertebroplasty and balloon kyphoplasty
Authors: Lewis Gladius , Koole Leo H. , van Hooy‐Corstjens Catharina S. J.
Published: June 2009

The interventional radiological techniques of vertebroplasty (VP) and balloon kyphoplasty (BKP) are widely used in cases where the pain secondary to compression fractures of vertebral bodies is severe, persistent, and refractory to conservative treatments. In the majority of VP and BKP cases, an injectable poly(methyl methacrylate) (PMMA) bone cement and different values of powder‐to‐liquid monomer ratio (PLMR) are used. A systematic study of the influence of PLMR on relevant cement properties is lacking. This was the subject of the present study, with the injectable PMMA bone cement used being an experimental one whose radiopacity is provided by an iodine‐containing compound in the powder. The PLMRs used—1.54, 2.22, and 3.08 g mL−1—are within the range used in clinical reports on VP and BKP. One property of the curing cement, namely, the polymerization rate at 37°C (k′), was estimated using nonisothermal differential scanning calorimetry results. The fatigue lives (Nf) of cured cement specimens were obtained under axial loading corresponding to axial stresses (S) of ±20.0, 15.0, 12.5, and 10.0 MPa, at a frequency of 2 Hz. The fatigue limit of the cement was estimated from the fit of the S − Nf results to the Olgive equation. With increase in PLMR, k′ increased significantly, but the influence of PLMR on the fatigue limit and on another property also estimated from the S − ln Nf results is not significant. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Forkhead transcription factor foxe1 regulates chondrogenesis in zebrafish
Authors: Nakada Chisako , Iida Atsumi , Tabata Yoko , Watanabe Sumiko
Published: June 2009

Forkhead transcription factor (Fox) e1 is a causative gene for Bamforth–Lazarus syndrome, which is characterized by hypothyroidism and cleft palate. Applying degenerate polymerase chain reaction using primers specific for the conserved forkhead domain, we identified zebrafish foxe1 (foxe1). Foxe1 is expressed in the thyroid, pharynx, and pharyngeal skeleton during development; strongly expressed in the gill and weakly expressed in the brain, eye, and heart in adult zebrafish. A loss of function of foxe1 by morpholino antisense oligo (MO) exhibited abnormal craniofacial development, shortening of Meckel's cartilage and the ceratohyals, and suppressed chondrycytic proliferation. However, at 27 hr post fertilization, the foxe1 MO‐injected embryos showed normal dlx2, hoxa2, and hoxb2 expression, suggesting that the initial steps of pharyngeal skeletal development, including neural crest migration and specification of the pharyngeal arch occurred normally. In contrast, at 2 dpf, a severe reduction in the expression of sox9a, colIIaI, and runx2b, which play roles in chondrocytic proliferation and differentiation, was observed. Interestingly, fgfr2 was strongly upregulated in the branchial arches of the foxe1 MO‐injected embryos. Unlike Foxe1‐null mice, normal thyroid development in terms of morphology and thyroid‐specific marker expression was observed in foxe1 MO‐injected zebrafish embryos. Taken together, our results indicate that Foxe1 plays an important role in chondrogenesis during development of the pharyngeal skeleton in zebrafish, probably through regulation of fgfr2 expression. Furthermore, the roles reported for FOXE1 in mammalian thyroid development may have been acquired during evolution. J. Exp. Zool. (Mol. Dev. Evol.) 312B:827–840, 2009. © 2009 Wiley‐Liss, Inc.
Use of fluorescence labeled mesenchymal stem cells in pluronic F127 and porous hydroxyapatite as a bone substitute for posterolateral spinal fusion
Authors: Chen Wen‐Jer , Huang Jau‐Wen , Niu Chi‐Chien , Chen Lih‐Huei , Yuan Li‐Jen , Lai Po‐Liang , Yang Chuen‐Yung , Lin Song‐Shu
Published: June 2009

Posterolateral spinal fusion is used to treat patients with degenerative spinal disorders. We investigated the effectiveness of a mesenchymal stem cell (MSC)/Pluronic F127/Interpore hybrid graft for spinal fusion in rabbits. Spinal fusion was examined using radiography, manual palpation, computed tomography (CT), torsional loading tests, and histological analysis. Using a PKH fluorescence labeling system, we also examined whether the newly formed bone was derived from the transplanted MSCs. We found that the MSCs adhered to the Interpore surface and within its pores, and differentiated into osteoblasts. Radiographs and CT images showed a continuous bone bridge and a satisfactory fusion mass incorporated into the transverse processes. The results of manual palpation and biomechanical data did not differ significantly from an autograft group. Histology from both groups revealed the presence of fibrous tissue, cartilage, and endochondral ossification in the gaps between the grafted fragments. In both groups, the degree of mature bone formation was greater at 12 weeks than at 6 weeks after grafting. Quantitative histomorphometry revealed no significant differences between the two groups at either time point. In situ tracing of the PKH 67‐labeled MSCs indicated that the transplanted MSCs were partly responsible for the new bone formation in both the repaired transverse processes and the grafted fragments. Thus, the MSC/Pluronic F127/Interpore hybrid graft could be used effectively to achieve posterolateral spinal fusion. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1631–1636, 2009
Relationship between solute transport properties and tissue morphology in human annulus fibrosus
Authors: Travascio Francesco , Jackson Alicia R. , Brown Mark D. , Gu Wei Yong
Published: June 2009

Poor nutritional supply to the intervertebral disc is believed to be an important factor leading to disc degeneration. However, little is known regarding nutritional transport in human annulus fibrosus (AF) and its relation to tissue morphology. We hypothesized that solute diffusivity in human AF is anisotropic and inhomogeneous, and that transport behaviors are associated with tissue composition and structure. To test these hypotheses, we measured the direction‐dependent diffusivity of a fluorescent molecule (fluorescein, 332 Da) in three regions of AF using a fluorescence recovery after photobleaching (FRAP) technique, and associated transport results to the regional variation in water content and collagen architecture in the tissue. Diffusivity in AF was anisotropic, with higher values in the axial direction than in the radial direction for all regions investigated. The values of the diffusion coefficient ranged from 0.38 ± 0.25 × 10−6 cm2/s (radial diffusivity in outer AF) to 2.68 ± 0.84 × 10−6 cm2/s (axial diffusivity in inner AF). In both directions, diffusivity decreased moving from inner to outer AF. Tissue structure was investigated using both scanning electron microscopy and environmental scanning electron microscopy. A unique arrangement of microtubes was found in human AF. Furthermore, we also found that the density of these microtubes varied moving from inner to outer AF. A similar trend of regional variation was found for water content, with the highest value also measured in inner AF. Therefore, we concluded that a relationship exists among the anisotropic and inhomogeneous diffusion in human AF and the structure and composition of the tissue. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1625–1630, 2009
Human papillomavirus in early laryngeal carcinoma
Authors: Baumann Jessica L. , Cohen Seth , Evjen Amy N. , Law Jonathan H. , Vadivelu Sangeetha , Attia Albert , Schindler Joshua S. , Chung Christine H. , Wirth Pamela S. , Meijer Chris J.L.M. , Snijders Peter J.F. , Yarbrough Wendell G. , Slebos Robbert J.C.
Published: June 2009

Objectives/Hypothesis:

To examine the role of HPV status in the etiology, prognosis, and treatment of head and neck squamous cell carcinoma in early larynx malignancies.

Study Design:

Retrospective.

Methods:

Thirty‐eight cases of T1 or carcinoma in situ (CIS) laryngeal lesions were examined for the presence of human papilloma virus (HPV) using an inclusive polymerase chain reaction (PCR)/hybridization technique capable of identifying 37 HPV subtypes.

Results:

HPV DNA was detected in 6 (16%) of the 38 lesions, representing HPV types 16, 26, 31, 39, and 52, and p16 tumor suppressor protein expression was confirmed in 10 representative cases. This HPV prevalence is higher than that noted in many previous laryngeal cancer studies, possibly due to the relatively large panel of subtypes screened for in this study. Identification of HPV‐26, which has been associated with uterine cervical cancer, in an early laryngeal cancer specimen represents the first evidence of this subtype in a laryngeal carcinoma. Consistent with reports focusing on head and neck squamous cell carcinoma (HNSCC) arising from other subsites within the upper aerodigestive tract, patients with HPV‐positive laryngeal carcinomas were of younger age and were somewhat less likely to have a history of tobacco use, although the latter of the two findings did not reach statistical significance.

Conclusions:

Our findings emphasize the presence of a broad spectrum of HPV types in a relevant proportion of early laryngeal cancers, and together with evidence of an association of HPV tumor status with a more favorable clinical course, provide a rationale for the routine HPV testing of small larynx lesions. Laryngoscope, 2009
Three‐dimensional femtosecond laser micromachining of photosensitive glass for biomicrochips
Authors: Sugioka K. , Hanada Y. , Midorikawa K.
Published: June 2009

Internal modification of transparent materials such as glass can be carried out using multiphoton absorption induced by a femtosecond (fs) laser. The fs‐laser modification followed by thermal treatment and successive chemical wet etching in a hydrofluoric (HF) acid solution forms three‐dimensional (3D) hollow microstructures embedded in photosensitive glass. This technique is a powerful method for directly fabricating 3D microfluidic structures inside a photosensitive glass microchip. We used fabricated microchips, referred to as a nanoaquarium, for dynamic observations of living microorganisms. In addition, the present technique can also be used to form microoptical components such as micromirrors and microlenses inside the photosensitive glass, since the fabricated structures have optically flat surfaces. The integration of microfluidics and microoptical components in a single glass chip yields biophotonic microchips, in other words, optofluidics, which provide high sensitivity in absorption and fluorescence measurements of small volumes of liquid samples.
Real‐time three‐dimensional single‐particle tracking spectroscopy for complex systems
Authors: Montiel D. , Yang H.
Published: June 2009

Complex systems are characterized by dynamical processes spread over multiple time and length scales. At a given instant, these systems can display spatial heterogeneities in which the local physical and chemical properties are nonuniform, depending on the location. They can also exhibit dynamical heterogeneities in which the local dynamical characteristics vary with time. These types of systems pose unique experimental challenges for their characterization and test of theoretical ideas. Recently, real‐time three‐dimensional (3D) single‐particle tracking spectroscopy has been developed to address these kinds of problems. With this approach, in principle, one can follow how a system evolves spatially as well as temporally. This article attempts to provide an introduction to this promising new technique by discussing the aims of studying a complex system and recent experimental advances towards this goal.
Erosion–corrosion characteristic of nano‐particulates reinforced Ni–Cr–Mo–Cu surface alloying layer in acidic flow and acidic slurry flow
Authors: Xu J. , Zhuo C.
Published: June 2009

In order to improve the corrosion and erosion–corrosion resistance of 316L stainless steel in engineering application, two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano‐SiC and Ni/nano‐SiO2 predeposited by brush plating, respectively, and a subsequent surface alloying with Ni–Cr–Mo–Cu by double glow process. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were performed on the two kinds of composite alloying layer using 10 wt% HCl solution to assess the corrosion behavior. Erosion–corrosion tests were carried out by erosion–corrosion test rig in acidic flow and acidic slurry flow for test time of 20 h at four different rotational speeds. Results of electrochemical tests indicated that the corrosion resistance of composite alloying layer with brush plating Ni/nano‐SiO2 particles interlayer approximated to that of single Ni‐based alloying layer, whereas the corrosion resistance of the composite alloying layer with brush plating Ni/nano‐SiC particles interlayer was apparently inferior to that of Ni‐based alloying layer in 10 wt% HCl solution at static state. Under the conditions of acidic flow and acidic slurry flow, the mass losses of tested samples increased with increase in the time of erosion–corrosion tests and the rotational speeds of samples. The mass losses of composite alloying layer with brush plating Ni/nano‐SiO2 particles interlayer were lower than that of single Ni‐based alloying layer at all rotational speeds, except at 1.88 m/s in acidic flow. The mass losses of composite alloying layer with brush plating Ni/nano‐SiC particles interlayer were higher than that of single Ni‐based alloying layer at all rotational speeds, but were obviously lower than that of AISI 316L stainless steel. The influences of second phase on the corrosion and erosion–corrosion of the two kinds of composite alloying layer were discussed in this paper.
Ex situ TEM observation of localized attack on AA 6061
Authors: Sun D. M. , Jiang Y. M. , Xiang Q. W. , Zhong C. , Gong J. , Zhang L. H. , Li J.
Published: June 2009

Ex situ transmission electron microscopy (TEM) was used in conjunction with energy dispersed spectrometry (EDS) to monitor evolution near the pre‐selected inclusions during initial stages of localized dissolution on the aluminum alloy (AA) 6061 immersed in 0.1 M NaCl solution. On the alloy TEM foil, Mg2Si phase particles were observed to preferentially dissolve after 3 min immersion. Nevertheless, different dissolution behaviors were observed to form in the vicinities of the different structure Fe‐rich precipitates; the trenches were observed near the anorthic phase particle, but no obvious priority dissolution was detected in the vicinity of hexagonal phase particles. The preferential sites of alloy dissolution were found to depend on both the component and the structure of the intermetallics. The shift of electrochemical potential was found to relate the dissolution of the heterogeneous phases.
On the importance of using known reference materials for the calibration of analytical methods — with particular reference to chloride and sodium content in hardened concrete
Authors: Miller J. B.
Published: June 2009

This paper treats the importance of calibrating procedures and methods of chemical analysis against known reference materials, and gives examples of how even accredited laboratories return erroneous results, with particular reference to the determination of chloride and sodium in hardened concrete. It is pointed out that much standardised work on methods has been laid down, but this has little value if reference materials are not available. A scheme that has been used for the production of reference material for this latter purpose is detailed.
Use of SECM to study the electrochemical behavior of DIN 1.4575 superferritic stainless steel aged at 475 °C
Authors: Terada M. , Padilha A. F. , Simões A. M. P. , de Melo H. G. , Costa I.
Published: June 2009

In order to lower the excessive costs of metallic prosthesis materials alternatives to Ti and Ti alloys have been searched. In this study, the corrosion resistance of the DIN 1.4575 superferritic stainless steel, either solution annealed or solution annealed and aged at 475 °C for periods varying from 100 to 1080 h, was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods in Hanks' solution. The solution annealed and the aged for 1080 h samples were also tested using scanning electrochemical microscopy (SECM) in a 0.1 mol/L NaCl solution at 25 °C. The EIS results showed that the corrosion resistance of the DIN 1.4575 steel decreases with heat treatment time at 475 °C probably due to alpha prime formation. Besides the diminution of the overall impedance values, the low frequency limit of the Nyquist diagrams show a progressive change from an almost capacitive response to a resistive behavior as the heat treatment time increases. Pitting corrosion resistance also decreased with aging time at 475 °C.
Amphiphilic Conetworks Based on End‐Linked Multiblock Copolymers of Different Numbers of Blocks and Constant Molecular Weight and Composition
Authors: Hadjiantoniou Natalie A. , Patrickios Costas S. , Thomann Yi , Tiller Joerg C.
Published: June 2009

Amphiphilic conetworks based on end‐linked copolymers of the hydrophilic ionizable 2‐(dimethylamino)ethyl methacrylate and the hydrophobic n‐butyl methacrylate bearing 3, 5, 7, and 9 blocks were synthesized using group transfer polymerization, and employing a bifunctional initiator and sequential addition of monomers and ethylene glycol dimethacrylate cross‐linker. All the linear precursors to the conetworks had the same molecular weight and composition, and differed only in their number of blocks. The aqueous degrees of swelling of the ionized conetworks increased with the number of blocks, manifesting the reduction of the driving force for nanophase separation, resulting from the reduction of the length of the hydrophobic segments. Reduction in the tendency for nanophase separation with increasing block number was also supported by atomic force microscopy on bulk conetworks, which indicated a decrease in the domain size as the number of blocks increased.

magnified image
Effect of Sonication on Polymeric Aggregates Formed by Poly(ethylene oxide)‐Based Amphiphilic Block Copolymers
Authors: Zhao Junpeng , Pispas Stergios , Zhang Guangzhao
Published: June 2009

The effect of sonication on the size and structure of polymeric aggregates formed by amphiphilic block copolymers was studied by the combination of dynamic and static light scattering. Poly(ethylene oxide)‐block‐polyisoprene, poly(ethylene oxide)‐block‐polystyrene diblock copolymers, and poly(ethylene oxide)‐block‐polyisoprene‐block‐poly(ethylene oxide) triblock copolymer were used as typical polymeric amphiphiles. Sonication was found to be an effective method to break up inter‐micellar associations and split large polymeric aggregates, present initially in the aqueous solutions, into monodisperse micelles. The content and type of hydrophobic block, copolymer solution‐preparation protocol, and copolymer concentration were also investigated as co‐factors in conjunction to the effect of sonication time.

magnified image
ICP‐MS‐Based strategies for protein quantification
Authors: Wang Meng , Feng Wei‐Yue , Zhao Yu‐Liang , Chai Zhi‐Fang
Published: June 2009

In the post‐genomics era, proteomics has become a central branch in life sciences. An understanding of biological functions will not only rely on protein identification, but also on protein quantification in a living organism. Most of the existing methods for quantitative proteomics are based on isotope labeling combined with molecular mass spectrometry. Recently, a remarkable progress that utilizes inductively coupled plasma‐mass spectrometry (ICP‐MS) as an attractive complement to electrospray MS and MALDI MS for protein quantification, especially for absolute quantification, has been achieved. This review will selectively discuss the recent advances of ICP‐MS‐based technique, which will be expected to further mature and to become one of the key methods in quantitative proteomics. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:326–348, 2010
Linear quadrupoles in mass spectrometry
Authors: Douglas D.J.
Published: June 2009

The use of linear quadrupoles in mass spectrometry as mass filters and ion guides is reviewed. Following a tutorial review of the principles of mass filter operation, methods of mass analysis are reviewed. Discussed are extensions of quadrupole mass filters to higher masses, scanning with frequency sweeps of the quadrupole waveform, operation in higher stability regions, and operation with rectangular or other periodic waveforms. Two relatively new methods of mass analysis the use of “islands of stability” and “mass selective axial ejection” are then reviewed. The optimal electrode geometry for a quadrupole mass filter constructed with round rods is discussed. The use of collisional cooling in quadrupole ion guides is discussed along with ion guides that have axial fields. Finally, mass analysis with quadrupoles that have large distortions to the geometry and fields is discussed. An Appendix gives a brief tutorial review of definitions of electrical potentials and fields, as well as the units used in this article. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:937–960, 2009
Deep brain stimulation in dystonia: Sonographic monitoring of electrode placement into the globus pallidus internus
Authors: Walter Uwe , Wolters Alexander , Wittstock Matthias , Benecke Reiner , Schroeder Henry W. , Müller Jan‐Uwe
Published: June 2009

Deep brain stimulation (DBS) of the globus pallidus internus (GPi) is an effective treatment in primary dystonia. Its success depends on the implantation accuracy of the DBS electrode into the targeted GPi. Discrepancies of up to 4 mm between the initial target, selected on preoperative MRI, and the final DBS lead location are caused mainly by caudal brain shift that occurs once the cranium is open. Nowadays, transcranial sonography (TCS) can display echogenic deep brain structures with higher image resolution compared to MRI under clinical conditions. Here, we demonstrate for the first time the use of a contemporary clinical high‐end TCS system for intraoperative monitoring of DBS electrode position. Herewith, a high‐resolution real‐time imaging of closely located microelectrodes and of the DBS lead through the intact skull is feasible. Simultaneous color‐coded sonographic imaging of arteries near the anatomical target allows further intraoperative refinement of DBS lead positioning, simultaneously preventing hemorrhages. © 2009 Movement Disorder Society
Assimilating humidity pseudo‐observations derived from the cloud profiling radar aboard CloudSat in ALADIN 3D‐Var
Authors: Storto Andrea , Thomas Tveter Frank
Published: June 2009

This paper describes an experimental procedure for assimilating CloudSat Cloud Profiling Radar (CPR) observations in ALADIN 3D‐Var through the use of humidity pseudo‐observations derived from a one‐dimensional Bayesian analysis. Cloud data are considered as binary occurrences (‘cloud’ vs ‘no‐cloud’), which makes the approach feasible to be extended to other cloudiness observations, and to any other binary observation in general. A simple large‐scale condensation scheme is used for projecting the prior information from a Numerical Weather Prediction model into cloud fraction space. Verification over a 1 month assimilation test period indicates a clear benefit of the pseudo‐observation assimilation scheme for the limited CloudSat CPR data set, especially in terms of improved skill scores for dynamical parameters such as geopotential and wind. Copyright © 2008 Royal Meteorological Society
Copula‐based drought severity‐duration‐frequency analysis in Iran
Authors: Shiau J. T. , Modarres R.
Published: June 2009

Drought is a complex and multi‐attribute natural hazard that has worldwide effects. Defined by a commonly used standardized precipitation index (SPI), each drought event is characterized by three correlated attributes: severity, duration and frequency. A probabilistic approach is developed to establish a drought severity‐duration‐frequency (SDF) relationship. Copulas are employed to construct the joint distribution function of drought severity and duration. Drought frequency, in terms of recurrence interval of drought events, is then related to the copula‐based distribution function via a conditional distribution function. The derived analytic drought SDF thus becomes a function of univariate distribution functions of drought severity and duration, a copula function which links the fitted univariate models, and the arrival rate of drought events. In this study, rainfall data for the period of 1954–2003 from two gauge stations in Iran, Abadan in the southwestern semi‐arid region and Anzali in the north humid region, are employed as an example to illustrate the proposed approach. From the derived drought SDF, drought severity in Anzali station is greater than those in Abadan station for given drought duration and recurrence interval. The results imply that the drought severity in humid region might be more severe if high rainfall fluctuations exist in that region. Copyright © 2009 Royal Meteorological Society
Tautomerism of 3‐nitro‐1,2,4‐triazole‐5‐one radical anions
Authors: Vakulskaya Tamara I. , Larina Lyudmila I. , Protsuk Nadezhda I. , Lopyrev Valentin A.
Published: June 2009

The non‐degenerate tautomers of 3‐nitro‐1,2,4‐triazole‐5‐one (NTO) radical anions were investigated for the first time by an ESR method during electrochemical reduction of NTO in an aprotic medium. Copyright © 2009 John Wiley & Sons, Ltd.
Prospective real‐time correction for arbitrary head motion using active markers
Authors: Ooi Melvyn B. , Krueger Sascha , Thomas William J. , Swaminathan Srirama V. , Brown Truman R.
Published: June 2009

Patient motion during an MRI exam can result in major degradation of image quality, and is of increasing concern due to the aging population and its associated diseases. This work presents a general strategy for real‐time, intraimage compensation of rigid‐body motion that is compatible with multiple imaging sequences. Image quality improvements are established for structural brain MRI acquired during volunteer motion. A headband integrated with three active markers is secured to the forehead. Prospective correction is achieved by interleaving a rapid track‐and‐update module into the imaging sequence. For every repetition of this module, a short tracking pulse‐sequence remeasures the marker positions; during head motion, the rigid‐body transformation that realigns the markers to their initial positions is fed back to adaptively update the image‐plane—maintaining it at a fixed orientation relative to the head—before the next imaging segment of k‐space is acquired. In cases of extreme motion, corrupted lines of k‐space are rejected and reacquired with the updated geometry. High‐precision tracking measurements (0.01 mm) and corrections are accomplished in a temporal resolution (37 ms) suitable for real‐time application. The correction package requires minimal additional hardware and is fully integrated into the standard user interface, promoting transferability to clinical practice. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Accelerated spectroscopic imaging of hyperpolarized C‐13 pyruvate using SENSE parallel imaging
Authors: Arunachalam Arjun , Whitt David , Fish Kenneth , Giaquinto Randy , Piel Joseph , Watkins Ronald , Hancu Ileana
Published: June 2009

The ability to accelerate the spatial encoding process during a chemical shift imaging (CSI) scan of hyperpolarized compounds is demonstrated through parallel imaging. A hardware setup designed to simultaneously acquire 13C data from multiple receivers is presented here. A system consisting of four preamplifiers, four gain stages, a transmit coil, and a four receive channel rat coil was built for single channel excitation and simultaneous multi‐channel detection of 13C signals. The hardware setup was integrated with commercial scanner electronics, allowing the system to function similar to a conventional proton multi‐channel setup, except at a different frequency. The ability to perform parallel imaging is demonstrated in vivo. CSI data from the accelerated scans are reconstructed using a self‐calibrated multi‐spectral parallel imaging algorithm, by using lower resolution coil sensitivity maps obtained from the central region of k‐space. The advantages and disadvantages of parallel imaging in the context of imaging hyperpolarized compounds are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Ultrathin polymer gate buffer layer for air‐stable, low‐voltage, n‐channel organic thin‐film transistors
Authors: Tanida Shinji , Noda Kei , Kawabata Hiroshi , Matsushige Kazumi
Published: June 2009

An ultrathin poly(methyl methacrylate) (PMMA) buffer layer was developed to improve the performance of n‐channel organic thin‐film transistors (OTFTs). The 8 nm‐thick PMMA film, prepared by spin‐coating, provided a very smooth surface and a uniform coverage on SiO2 surface reproducibly, which was confirmed by X‐ray reflectivity (XR) measurement. Then, we fabricated N,N′‐ditridecyl‐3,4,9,10‐perylenetetracarboxylic diimide (PTCDI‐C13) thin‐film transistors with and without this 8 nm‐thick PMMA insulating layer on SiO2 gate insulators and achieved one‐order increase of field‐effect mobility (up to 0.11 cm2/(Vs) in a vacuum), one‐half decrease of threshold voltage, and reduction of current hysteresis with the PMMA layer. Only TFTs with the PMMA layer displayed n‐channel operation in air and showed field‐effect mobility of 0.10 cm2/(Vs). We consider that electrical characteristics of n‐channel OTFTs were considerably improved because the ultrathin PMMA film could effectively passivate the SiO2 insulator surface and decrease interfacial electron traps. This result suggests the importance of the ultrathin PMMA layer for controlling the interfacial state at the semiconductor/insulator interface and the device characteristics of OTFTs. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of telomeres in peripheral blood cells from patients with bone marrow failure
Authors: Pavesi Elisa , Avondo Federica , Aspesi Anna , Quarello Paola , Rocci Alberto , Vimercati Chiara , Pigullo Simona , Dufour Carlo , Ramenghi Ugo , Dianzani Irma
Published: June 2009

Background

The determination of telomere length is useful for the characterization of dyskeratosis congenita (DC) and of aplastic anemias (AA) as well as hematological malignancies. Short telomeres result from a specific defect of telomere maintenance in DC and likely from higher cellular turnover in AA and hematological malignancies. Data are not conclusive for Diamond‐Blackfan anemia (DBA), a pure erythroid aplasia due to defects of ribosomal proteins. Our aim was to evaluate the utility of a qPCR method for telomere length assessment to evaluate the diagnostic contribution of telomere measurement in bone marrow failure syndromes (BMFS).

Procedure

Telomere length was evaluated by qPCR in peripheral blood cells from 95 normal individuals and 62 patients with BMFS, including 45 patients with DBA.

Results

Results obtained with qPCR are comparable with other quantitative methods, such as flow‐FISH and Southern blotting. Our data show that only one DBA patient and a minority of other BMFS patients have very short telomeres, defined as less than the 1st percentile of controls.

Conclusions

The qPCR method for telomere length evaluation is an easy alternative to other methods and may thus be valuable in a clinical hematological laboratory setting. Telomere maintenance does not seem to be involved in the pathogenesis of DBA unlike in other BMFSs. Pediatr Blood Cancer 2009;53:411–416. © 2009 Wiley‐Liss, Inc.
Medulloblastoma in a child with down syndrome: Long‐term remission with multimodality treatment
Authors: Benesch Martin , Moser Andrea , Sovinz Petra , Lackner Herwig , Schwinger Wolfgang , Eder Hans , Urban Christian
Published: June 2009

A 4¾‐year‐old male with Down syndrome (DS) presented with unsteady gait and fatigue. Neuroimaging revealed a cerebellar mass with concomitant obstructive hydrocephalus and additional metastatic lesions. He was successfully treated and is still in complete remission 5 years from diagnosis. The present case illustrates that, although not yet reported, medulloblastoma can also occur in patients with DS. Pediatr Blood Cancer 2009;53:1150–1151. © 2009 Wiley‐Liss, Inc.
The influence of maternal opiate use in pregnancy on second trimester biochemical markers for Down syndrome
Authors: Scott G. J. , Holding S. , Purcell A. , Tutty S. , Lindow S. W.
Published: June 2009

Objective

The object of this study is to examine the influence of maternal opiate use on the levels of second trimester biochemical markers for Down syndrome. Maternal opiate use is known to be associated with problems of placental origin and it is possible that the secretion of alpha‐feto protein (AFP), free‐beta human chorionic gonadotrophin (HCG) and unconjugated oestriol (UE) differs from that of a normal population.

Method

Seventy nine women who used opiates in pregnancy were compared to a control group of seventy nine women who did not use opiates and their adjusted marker levels analysed.

Results

The adjusted median MoM in the opiate and control groups respectively were: AFP (1.00 vs 0.94), HCG (0.95 vs 1.04) and UE (0.96 vs 1.02), with no significant difference between these groups.

Conclusion

This study suggests that the current practice of calculating the risk of Down syndrome from second trimester biochemistry in women using opiate can be performed using data derived from a normal population. Copyright © 2009 John Wiley & Sons, Ltd.
Gibbs energy of cooperative hydrogen‐bonding interactions in aqueous solutions of amines and pyridines
Authors: Solomonov Boris N. , Sedov Igor A. , Akhmadiyarov Aydar A.
Published: June 2009

A method to determine the Gibbs energy of specific (hydrogen bonding) interactions of a solute with water is proposed. The energies of hydrogen bonding in bulk water are very difficult to determine by any method. The Gibbs energy of hydration of substances forming hydrogen bonds with water is considered as the sum of contributions due to non‐specific interactions, the hydrophobic effect, and specific interactions. The first two terms were found to be rather accurately described by empirical equations. The Gibbs energies of hydrogen bonding of aliphatic amines and pyridines in bulk water are determined, and the results are compared with the energies of their complexes with one molecule of water. The cooperativity of hydrogen bonding is proved in aqueous solutions of amines and pyridines. To use our equations, experimental values of the Gibbs energies of solvation in 'standard' solvents need to be known. The Gibbs energies of solvation of ten amines and pyridines in dimethyl sulfoxide are determined experimentally using chromatographic head space analysis. The tendencies observed for the series of amines and pyridines are in agreement with other studies. Copyright © 2009 John Wiley & Sons, Ltd.
Targeting of prostate cancer cells by a cytotoxic lentiviral vector containing a prostate stem cell antigen (PSCA) promoter
Authors: Petrigliano Frank A. , Virk Mandeep S. , Liu Nancy , Sugiyama Osamu , Yu Duan , Lieberman Jay R.
Published: June 2009

BACKGROUND

The efficacy of prostate cancer gene therapy is limited by the inefficiency of prostate‐specific promoters as compared to ubiquitous viral promoters. The purpose of this investigation was to evaluate the specificity and efficacy of a lentiviral vector driven by a PSCA promoter.

METHODS

Prostate cancer (LNCap, C42‐B, and LAPC‐4) and non‐prostate cancer (HeLa, MB231, and MCF‐7) cells were transduced with a lentiviral vector expressing either the luciferase or the HSV‐TK suicide gene and driven by a short PSCA promoter. Specificity and efficacy were evaluated in vitro and in vivo.

RESULTS

Luciferase expression was only detected in prostate cancer cells and was comparable to the universal CMV promoter. Luciferase expression in prostate cancer cells cultured with androgen was higher than that in cells cultured without androgen. In subsequent cytotoxicity experiments in which the luciferase marker gene was replaced with the HSV‐TK gene, the lentiviral vector harboring the PSCA promoter induced cytotoxicity in prostate cancer cell lines while demonstrating a minimal effect on non‐prostate cells. Cellular toxicity was correlated to increasing concentrations of the prodrug ganciclovir. Androgen had a positive effect on the cytotoxicity of this lentiviral construct. Intratumoral injection of prostate cancer xenografts with the lentiviral construct induced tumor growth inhibition versus saline controls.

CONCLUSION

Our results indicate that a lentiviral gene therapy vector driven by a short PSCA promoter can induce prostate‐specific cellular toxicity in vivo and in vitro and may provide a strategy to selectively treat local and advanced metastatic prostate cancer. Prostate 69: 1422–1434, 2009. © 2009 Wiley‐Liss, Inc.
Magnetic plasmon‐polaritons in negative‐index metallic antiferromagnets
Authors: Tarkhanyan Roland H. , Niarchos Dimitris G.
Published: June 2009

A simple model is proposed for understanding of the main properties of backward electromagnetic waves in conducting antiferromagnetic crystals in the presence of an external magnetic field. Necessary conditions are found for realization of the negative refraction in the case of the Voigt geometry and the corresponding frequency regions are determined. It is shown that the behavior of the waves in various ranges of the magnetic field is quite different, and both the number and the limits of the frequency ranges, where the material behaves as an absolute left‐handed medium, are very sensitive to the strength of the field. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The total energy splitting of ionic eigenstates in the axial crystal fields
Authors: Mulak Jacek , Mulak Maciej
Published: June 2009

The relationship between the energy total splitting ΔE of the free‐ion electron states in the axial crystal‐fields and the second moment of that splitting σ2 is thoroughly investigated. The non‐Kramers and Kramers states with the quantum number 1 ≤ J ≤ 8 in the axial crystal‐fields of any multipolar composition but fixed σ2 are considered. Since the crystal‐field Hamiltonian ℋ︁CF is a superposition of the three effective multipoles various ΔE can correspond to a fixed σ2 according to the resultant combination of the independent contributions. This ΔE variation range is the subject of the study. For the states under examination ΔE can take the values from 2.00σ to 3.75σ, whereas the difference ΔEmax – ΔEmin, except the states with J ≤ 5/2, amounts roughly to σ.

For comparison, the one‐multipolar ℋ︁CFs yield accurately defined ΔE ranging from 2.50σ to 3.00σ. The limitations of the allowed ΔE values exclude rigorously a number of virtually possible splitting diagrams. The documentary evidence for this restriction has been supplied in the paper collating the nominally admissible total energy splittings Δℰ (i.e. those preserving the σ2) with the (ΔEmin, ΔEmax) ranges occurring in the actual axial crystal‐fields. Although the ΔE unlike the σ2 is not an essential characteristic and depends on the reference frame orientation, it is useful to know its dispersion range, particularly attempting to assign or verify complex electron spectra. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical studies of EPR g ‐factors and microstructure of the two tetragonal palladium centers in silver chloride
Authors: Feng W. L.
Published: June 2009

The EPR g ‐factors g∥, g⊥ for two tetragonal Pd+ impurity centers (i.e. Pd+ I and II centers) in AgCl crystal are calculated by using the high‐order perturbation formulas of EPR parameters for the 4d9 ion in tetragonal symmetry with the ground state |dx 2–y 2〉. Based on the calculations, the defect models for the two centers are suggested as a substitutional Ag+ ion with (PdCl6)5– or the [(PdCl6)5– – VAg+] cluster. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐throughput approaches towards the definitive identification of pharmaceutical drug metabolites. 2. An example of how unexpected dissociation behaviour could preclude correct assignment of sites of metabolism
Authors: Holman Stephen W. , Wright Patricia , Langley G. John
Published: June 2009

S‐oxidation is a common metabolic route for sulfur‐containing compounds. Whilst investigating the dissociation of a series of chemically synthesised model S‐oxide metabolites, two unexpected losses of 62 m/z units were observed in the collision‐induced dissociation (CID) product ion spectrum of protonated 3‐dimethylaminomethyl‐4‐(4‐methanesulfinyl‐3‐methylphenoxy)benzenesulfonamide. A single loss was initially assigned using the low‐resolution product ion spectrum, acquired by electrospray ionisation quadrupole ion trap mass spectrometry (ESI‐QIT‐MS), as methanethial, S‐oxide via a charge‐remote, four‐centred rearrangement. This assignment was consistent with well‐documented hydrogen rearrangements in the literature. Further, the loss was not observed for the parent compound. Thus, it was inferred that the site of metabolism was involved in the dissociation and the attractive nature of the four‐centred rearrangement meant that the loss of methanethial, S‐oxide was a logical assignment. However, deuterium‐labelling experiments and accurate mass measurements, performed using electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI‐FT‐ICR‐MS), showed that the nominal loss of 62 m/z units occurs via two distinct dissociation pathways. Neither of these losses was of methanethial, S‐oxide as initially hypothesised from the low‐resolution product ion spectrum of the protonated molecule. Mechanisms consistent with the experimental findings are postulated. An MS3 spectrum of the fully exchanged, deuterated species supported the proposed mechanisms by suggesting that 3‐dimethylaminomethyl‐4‐(4‐methanesulfinyl‐3‐methylphenoxy)benzenesulfonamide has multiple sites of protonation in the gas phase. The planar structures of the posited product ions are likely to provide the driving force for the rearrangements. The relevance of the observations with regards to pharmaceutical drug metabolite identification is discussed. Copyright © 2009 John Wiley & Sons, Ltd.
δ13C,δ15N andδ2H isotope ratio mass spectrometry of ephedrine and pseudoephedrine: application to methylamphetamine profiling
Authors: Collins Michael , Cawley Adam T. , Heagney Aaron C. , Kissane Luke , Robertson James , Salouros Helen
Published: June 2009

Conventional chemical profiling of methylamphetamine has been used for many years to determine the synthetic route employed and where possible to identify the precursor chemicals used. In this study stable isotope ratio analysis was investigated as a means of determining the origin of the methylamphetamine precursors, ephedrine and pseudoephedrine. Ephedrine and pseudoephedrine may be prepared industrially by several routes. Results are presented for the stable isotope ratios of carbon (δ13C), nitrogen (δ15N) and hydrogen (δ2H) measured in methylamphetamine samples synthesized from ephedrine and pseudoephedrine of known provenance. It is clear from the results that measurement of theδ13C,δ15N andδ2H stable isotope ratios by elemental analyzer/thermal conversion isotope ratio mass spectrometry (EA/TC‐IRMS) in high‐purity methylamphetamine samples will allow determination of the synthetic source of the ephedrine or pseudoephedrine precursor as being either of a natural, semi‐synthetic, or fully synthetic origin. Copyright © 2009 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.
Microstructure and interfacial adhesion of high velocity oxy‐fuel‐sprayed MoB–CoCr alloy coating on 316L stainless steel
Authors: Lv Heping , Nie Pulin , Yan Yonggen , Wang Jun , Sun Baode
Published: June 2009

In this article, a newly developed MoB–CoCr alloy coating was deposited on 316L stainless steel substrate by high velocity oxy‐fuel thermal spraying process. The microstructures and interfacial adhesion of the alloy coating were determined by scanning electron microscopy, X‐ray diffraction and three‐point bending. The results show that the coating consisted of ternary transition metal boride matrix phases (CoMo2B2, CoMoB) and a little amount of binary borides (MoB and CrB), the former composed of partially amorphous phase. The formation of the amorphous phase was attributed to the high cooling rates of molten droplets and the proper powder compositions. In the interfacial adhesion measurement, the delamination of the coating is induced during the three‐point bending test, and the interfacial fracture toughness is analyzed using a finite element analysis model. The critical load is determined by comparing the load versus deflection curves obtained by finite element analysis under assumed no crack conditions with the experimental data, and other inputs are determined by test. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and Stretching of Rolling Circle Amplification Products in a Flow‐Through System
Authors: Reiß Edda , Hölzel Ralph , Bier Frank F.
Published: June 2009

Enzymatic isothermal rolling circle amplification (RCA) produces long concatemeric single‐stranded DNA (ssDNA) molecules if a small circular ssDNA molecule is applied as the template. A method is presented here in which the RCA reaction is carried out in a flow‐through system, starting from isolated surface‐tethered DNA primers. This approach combines gentle fluidic handling of the single‐stranded RCA products, such as staining or stretching via a receding meniscus, with the option of simultaneous (fluorescence) microscopic observation. It is shown that the stretched and surface‐attached RCA products are accessible for hybridization of complementary oligonucleotides, which demonstrates their addressability by complementary base pairing. The long RCA products should be well suited to bridge the gap between biomolecular nanoscale building‐blocks and structures at the micro‐ and macroscale, especially at the single‐molecule level presented here.
Facilitation of glutamate release from rat cerebral cortex nerve terminal by subanesthetic concentration propofol
Authors: Lu Cheng‐Wei , Lin Tzu‐Yu , Chiang Han‐Sun , Wang Su‐Jane
Published: June 2009

Propofol is now the most commonly used intravenous anesthetic‐for general anesthesia and sedation because of its rapid onset and recovery. Besides the well‐known adverse effects of cardiovascular and respiratory depression, recent studies indicate that propofol may cause excitatory phenomena such as myoclonus, opisthotonus, and even seizure. However, the mechanisms of these excitatory effects of propofol have not been elucidated. Considering glutamate as the principle excitatory neurotransmitter in the central nervous system and excessive glutamatergic synaptic transmission can cause seizure, we examined the effect of propofol on the release of glutamate from rat cerebral cortex nerve terminals (synaptosomes). Results showed that subanesthetic concentration propofol facilitated 4‐aminopyridine (4‐AP), but not KCl‐ or ionomycin‐evoked glutamate release from nerve terminals. The facilitation of 4‐AP‐evoked glutamate release by propofol also occurred in the calcium chelation and significantly attenuated by glutamate transporter inhibitors, DL‐threo‐β‐benzyloxyaspartic acid (DL‐TBOA) and L‐trans‐pyrrolidine‐2,4‐dicarboxylic acid (L‐trans‐PDC). In addition, propofol increased 4‐AP‐evoked depolarization of the plasma membrane potential. Furthermore, protein kinase C (PKC) inhibition suppressed propofol‐mediated facilitation of glutamate release. These results suggest that subanesthetic concentration propofol facilitates glutamate release from rat cerebrocortical glutamatergic terminals by increasing nerve terminal excitability, likely through the activation of PKC pathway. This finding may provide an explanation for propofol‐induced excitatory phenomena. Synapse 63:773–781, 2009. © 2009 Wiley‐Liss, Inc.