bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased risk of essential tremor in first‐degree relatives of patients with Parkinson's disease
Authors: Rocca Walter A. , Bower James H. , Ahlskog J. Eric , Elbaz Alexis , Grossardt Brandon R. , McDonnell Shannon K. , Schaid Daniel J. , Maraganore Demetrius M.
Published: June 2007

We conducted a historical cohort study of 981 first‐degree relatives of 162 patients with Parkinson's disease (PD) and of 838 first‐degree relatives of 147 controls representative of the population of Olmsted County, Minnesota. In addition, we studied 2,684 first‐degree relatives of 411 patients with PD referred to the Mayo Clinic. Relatives were interviewed and screened for tremor either directly or through a proxy, and those who screened positive were examined or copies of their medical records were obtained to confirm the diagnosis of essential tremor (ET). We also obtained ET information from a medical records‐linkage system (family study method). In the population‐based sample, the risk of ET was significantly increased for relatives of patients with onset of PD ≤ 66 years (first tertile; hazard ratio [HR] = 2.24; 95% confidence interval [95% CI] = 1.26–3.98; P = 0.006). In the referral‐based sample, the risk of ET among relatives increased with younger onset of PD in patients (linear trend; P = 0.001), and was higher in relatives of PD patients with the tremor‐predominant or mixed form when compared with relatives of patients with the akinetic‐rigid form, and in men compared with women. These findings suggest that PD and ET may share familial susceptibility factors. © 2007 Movement Disorder Society
On the structural stability of thermoelastic model of porous media
Authors: Chiriţă Stan , Ciarletta Michele
Published: June 2007

In the present paper we study the structural stability of the mathematical model of the linear thermoelastic materials with voids. We prove that the solutions of problems depend continuously on the constitutive quantities, which may be subjected to error or perturbations in the mathematical modelling process. Thus, we assume to have changes in the various coupling coefficients of the model and then we establish estimates of continuous dependence of solutions. We have to outline that such estimates play a central role in obtaining approximations to these kinds of problems.

To derive a priori estimates for a solution we first establish appropriate bounds for the solutions of certain auxiliary problems. These are achieved by means of so‐called Rellich‐like identities.

We also investigate how the solution in the coupled model behaves as some coupling coefficients tend to zero. Copyright © 2007 John Wiley
& Sons, Ltd.
Cranberry and blueberry: Evidence for protective effects against cancer and vascular diseases
Authors: Neto Catherine C.
Published: May 2007

Growing evidence from tissue culture, animal, and clinical models suggests that the flavonoid‐rich fruits of the North American cranberry and blueberry (Vaccinium spp.) have the potential ability to limit the development and severity of certain cancers and vascular diseases including atherosclerosis, ischemic stroke, and neurodegenerative diseases of aging. The fruits contain a variety of phytochemicals that could contribute to these protective effects, including flavonoids such as anthocyanins, flavonols, and proanthocyanidins; substituted cinnamic acids and stilbenes; and triterpenoids such as ursolic acid and its esters. Cranberry and blueberry constituents are likely to act by mechanisms that counteract oxidative stress, decrease inflammation, and modulate macromolecular interactions and expression of genes associated with disease processes. The evidence suggests a potential role for dietary cranberry and blueberry in the prevention of cancer and vascular diseases, justifying further research to determine how the bioavailability and metabolism of berry phytonutrients influence their activity in vivo.
Currents reconstruction using a modal expansion of near field measurements for synthesis error detection
Authors: Sanchez Daniel , Baquero Mariano , Rodrigo Vicent Miquel , Bernardo Bernardo
Published: May 2007

A new procedure for obtaining the equivalent currents on a plane surface from spherical near field measurements is proposed. It uses the modal expansion in spherical waves and the plane wave spectrum to achieve the objective. Some results using real measurements are shown. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2043–2047, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22575
Instrument panel mount GPS antenna
Authors: Yegin Korkut
Published: May 2007

When the GPS antenna is mounted inside the instrument panel or dashboard of a vehicle, its passive antenna performance is adversely affected. Free space and vehicle level measurements are performed to understand the extent of degradation. Then, the antenna with a low‐noise amplifier is connected to a GPS receiver, and the number of satellites tracked in a 24‐h period is recorded for system performance. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1979–1981, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22579
Design of multi‐layered polygonal helix antennas for RFID applications
Authors: Choo Jaeyul , Choo Hosung , Park Ikmo , Oh Yisok
Published: May 2007

In this letter, we propose a novel printed helix antenna for an RFID reader in the UHF band. The printed microstrip line of the antenna is first wound outside a polygonal‐shaped layer and then wound on an inner layer to control the overall gain and the radiation pattern of the antenna. On each layer, the winding pitch angles can have either negative or positive values, which results in a circularly polarized (CP) broad bandwidth. The structural details of the antenna were optimized using the Pareto genetic algorithm (GA), which allowed for excellent performance with the use of RFID reader antennas. The optimized two‐layered polygonal helix was fabricated on a flexible cardboard substrate. Performances of the antenna were measured and compared with those of simulations. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1971–1974, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22595
Novel dual‐band WLAN antennas with integrated band‐select filter for 802.11 a/b/g WLAN radios in portable devices
Authors: Demir Veysel , Huang Chun‐Wen Paul , Elsherbeni Atef
Published: May 2007

Novel dual‐band WLAN antenna system with integrated band‐select filter is designed. This integrated antenna design system provide VSWR <2:1 for both 2.4–2.5 GHz and 4.9–5.85 GHz with omni‐directional radio patterns. Based on these features, a novel architecture for a dual‐band WLAN radio Front‐End in portable devices can be achieved. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1868–1872, 2007; Published online in Wiley Inter‐Science (www.interscience.wiley.com). DOI 10.1002/mop.22601
Research on broadband characteristics of double folded‐slot antenna with back ground conductor
Authors: He Qing‐Qiang , Wang Bing‐Zhong , Yin Zhong‐Liang
Published: May 2007

A novel wideband coplanar waveguide‐fed double folded‐slot antenna with back ground conductor is proposed and studied. The design considerations for achieving broadband operation of the proposed double folded‐slot antenna are described. Return loss and radiation pattern are measured. The obtained results show that the impedance bandwidth, determined by 10 dB return loss of the proposed double folded‐slot antenna can be greater than 30%, and can be used for the engineering. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1829–1833, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22603
A current reused CMOS quadrature injection‐locked frequency divider
Authors: Chuang Yun‐Hsueh , Jang Sheng‐Lyang , Lee Shao‐Hwa , Chiang Yeuh‐Hua
Published: May 2007

A new current‐reused injection‐locked frequency divider is proposed to generate quadrature outputs and implemented using the standard UMC 0.18 μm CMOS 1P6M process. The proposed circuit is made of two LC‐tank voltage controlled oscillators (VCOs) stacked in series and the VCOs are coupled with the coupling transistors to generate quadrature signals. The direct injection‐locked technique is applied to the VCO to perform a divide by two functions, so that the quadrature circuit can provide low phase noise signal. At the 1.8 V supply voltage, the free running frequency of proposed circuit operates from 2.3 to 2.63 GHz and provides 1 GHz locking from 4.43 to 5.43 GHz. The power consumption is 7.4 mW with 4.1 mA current consumption. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1804–1806, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22604
High‐order accurate FDTD method based on the combination of staggered backward differentiation integrator with optimal central finite difference scheme
Authors: Xiao Fei , Tang Xiaohong
Published: May 2007

In this letter, a high order accurate FDTD method is proposed, in which a fourth‐order accurate staggered backward differentiation integrator is used for time marching and a new finite difference scheme named the optimal central finite difference scheme is used for spatial discretization. The analysis shows that the numerical dispersion of the new method can be reduced to some extent in comparison with that of the former fourth‐order accurate FDTD method while no extra computation cost is involved. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1802–1804, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22605
A novel all‐fiber high velocity interferometer for any reflector
Authors: Hong Guang‐Wei , Jia Bo , Wang Xiang
Published: May 2007

A novel all‐fiber high velocity interferometer system for any reflector (AFHVISAR) is proposed and demonstrated. The system mainly consists of two 3 × 3 SM fiber couplers. A quasi‐direct current (QDC) signal directly from the moving surface is obtained and used to offset the QDC component in the interfering signals for more precise phase demodulation. The use of the diffuse surface solves the fringe loss problem induced by the nonparallel movements of the surface. The experiment with a one‐stage light gas gun shows that the AFHVISAR can successfully achieve the surface velocity profile of LY12 aluminum specimen. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2032–2035, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22606
Small printed magnetic dipole
Authors: Rudant L. , Delaveaud C.
Published: May 2007

A very compact antenna with magnetic dipole radiation properties is presented. It is horizontally polarized HP with low cross polarization level XPR, it has omnidirectional radiation with a very low ripple in the azimuth cut plane. With a compact design (quarter wavelength square) it is suitable for integration into small WLAN devices. When combined with other radiating elements, this antenna offers new opportunities for diversity system deployment. This antenna can be equally used for propagation channel characterization as a reference for horizontally polarized waves. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1862–1864, 2007; Published online in Wiley Inter‐Science (www.interscience.wiley.com). DOI 10.1002/mop.22617
An extendedZYT‐chart for conjugately characteristic‐impedance transmission lines with active characteristic impedances
Authors: Torrungrueng D. , Chou P. Y. , Krairiksh M.
Published: May 2007

It has been shown recently in the literature that the conjugately characteristic‐impedance transmission lines (CCITLs) implemented by periodically loaded lossless lines can exhibit active characteristic impedances (i.e., negative characteristic resistances). In this case, the magnitude of the voltage reflection coefficient is always greater than or equal to unity for passive load termination. Because of this reason, some modifications to the standard T‐chart, a graphical tool for solving CCITL problems, is necessary. The modified chart is called as an extended ZY T‐chart, where the range of plotting is always outside or on the unit circle of the voltage reflection coefficient Γ plane. It is found that the extended chart depends on the angle ϕ, the argument of the CCITL characteristic impedances, in a complicated fashion. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1961–1964, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22626
60‐GHz CPW‐fed dielectric‐resonator‐above‐patch (DRAP) antenna for broadband WLAN applications using micromachining technology
Authors: Oh Jungsuek , Baek Taejong , Shin Donghoon , Rhee Jinkoo , Nam Sangwook
Published: May 2007

A 60‐GHz coplanar waveguide (CPW)‐fed dielectric‐resonator‐above‐patch (DRAP) antenna using micromachining technology is presented. In the proposed structure, the patch is elevated in the air with support of a dielectric‐post, and a rectangular dielectric resonator antenna (RDRA) is fixed above the patch. The size of the RDR is 1 × 0.8 mm2. We introduce a novel use of micromachining technology (solder ball bumping and flip chip bonding) for the first time to exactingly align and bond a small RDRA with a feed‐slot. The fabricated antenna shows broadband characteristics such as −10‐dB bandwidth of 17.5 GHz from 54 to 71.5 GHz, corresponding to a fractional bandwidth of 29.2%. Moreover, the radiation pattern could be measured by integrating the proposed antenna with a 60‐GHz VCO. An antenna gain of about 3.6 dBi at 60 GHz is measured. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1859–1861, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22632
Highly saturated EDFA for gain clamping operation
Authors: Muhd‐Yassin S. Zen , Harun S. W. , Ahmad H. , Abd‐Rahman M. Kamil
Published: May 2007

A highly saturated erbium‐doped fiber amplifier (EDFA) that can be used for gain‐clamping is demonstrated. This amplifier utilizes a short length of active fiber to provide a small but maximum gain and a high pump power to enhance the gain dynamic range. The gain for two simultaneous equal strength input signal channels is clamped at 19.3 dB from −34 dBm to −14 dBm with gain variation of less than 1 dB. The corresponding noise figure is obtained at 3.4 dB, which is slightly lower compared with the normal EDFA. This amplifier is expected to have a low transient power excursion since no compensating light is used inside the system. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1815–1816, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22635
Solid‐state 17O NMR study of the electric‐field‐gradient and chemical shielding tensors in polycrystalline amino acids
Authors: Yamada Kazuhiko , Shimizu Tadashi , Tansho Masataka , Nemoto Takahiro , Asanuma Miwako , Yoshida Mitsuru , Yamazaki Toshio , Hirota Hiroshi
Published: May 2007

We have presented a systematic experimental investigation of carboxyl oxygen electric‐field‐gradient (EFG) and chemical shielding (CS) tensors in crystalline amino acids. Three 17O‐enriched amino acids were prepared: L‐aspartic acid, L‐threonine, and L‐tyrosine. Analysis of two‐dimensional 17O multiple‐quantum magic‐angle spinning (MQMAS), MAS, and stationary NMR spectra yields the 17O CS, EFG tensors and the relative orientations between the two tensors for the amino acids. The values of quadrupolar coupling constants (CQ) are found to be in the range of 6.70–7.60 MHz. The values of δiso lie in the range of 268–292 ppm, while those of the δ11 and δ22 components vary from 428 to 502 ppm, and from 303 to 338 ppm, respectively. There is a significant correlation between the magnitudes of δ22 components and CO bond lengths. Since CO bond length may be related to hydrogen‐bonding environments, solid‐state 17O NMR has significant potential to provide insights into important aspects of hydrogen bonds in biological systems. Copyright © 2007 John Wiley & Sons, Ltd.
Normal carbon acid referencing for protein amide hydrogen exchange
Authors: LeMaster David M. , Anderson Janet S. , Hernández Griselda
Published: May 2007

Measurement of the exchange kinetics for amide hydrogens along the protein backbone continues to offer valuable insights into structural stability and conformational dynamics. Since such studies routinely compare samples that differ in solution conditions or mechanical handling, normalization of the relative exchange rates can present a potentially significant source of experimental uncertainty. The carbon acids 1,3‐dimethylimidazolium cation and thiomethylacetonitrile exhibit base catalyzed exchange rates similar to those of the slowly exchanging amides, under conditions typical for protein studies. With 13C enrichment at the acidic carbon position to facilitate selective observation, such carbon acids offer practical internal calibration of exchange. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental and DFT studies on the transmission mechanisms of analogous NMR JCH and JCC couplings in 1‐X‐ and 1‐X‐3‐methylbicyclo[1.1.1]‐pentanes
Authors: Contreras Rubén H. , Esteban Ángel L. , Díez Ernesto , Lochert Ian J. , Della Ernest W. , Tormena Cláudio F.
Published: May 2007

The main aim of this work is to compare the transmission mechanisms for the Fermi contact term of spin–spin couplings, SSCCs, in series 1‐X‐bicyclo[1.1.1]‐pentane, (1), and 1‐X‐3‐methylbicyclo[1.1.1]pentane, (2), and from that comparison to gain insight into some subtle aspects of the FC transmission. To this end, 18 members of the latter series were isotopically enriched in 13C at the methyl position and the following couplings were measured; 1J, 3J and 4J. These three types of SSCCs in (2) are compared, respectively, with 1J, 3J and 4J in (1); these latter values were taken from previous works. Since electron delocalization plays an important role in the transmission of the FC interaction, the natural bond orbital (NBO) method is employed to quantify electron delocalization interactions within selected members of series (1) and (2). It is found that 1J SSCCs in (1) is more efficiently transmitted than 1J SSCCs in (2). On the other hand, 3J and 4J SSCCs in (1) are notably less efficiently transmitted than 3J and 4J SSCCs in (2), although substituent effects on these two SSCCs show the opposite trends. These different efficiencies are rationalized in terms of different σ‐hyperconjugative interactions in both series of compounds. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental and theoretical investigation of NMR 2JHH coupling constant on six‐membered ring systems containing oxygen or sulfur atoms
Authors: Tormena Cláudio F. , Vilcachagua Janaína D. , Karcher Viviane , Rittner Roberto , Contreras Rubén H.
Published: May 2007

Theoretical and experimental 2JHH coupling constants for six‐membered rings containing oxygen or sulfur atoms were studied to investigate whether the 2JHH coupling constant can be used for stereoelectronic studies in heterocyclohexanes, instead of 1JCH, because it is well known that experimental measurements of 2JHH coupling constants at low temperature are much easier to determine than the corresponding 1JCH couplings. For all compounds studied here, the 2JHH coupling constants are affected by σ*C–H antibonding occupancy together with bond angle effects. For cyclohexane and oxygen‐containing compounds, the influence on the geminal coupling for Hax‐C2‐Heq and for X1‐C2‐X3 (X = O and C), bond angles are more pronounced than for the sulfur derivatives. Copyright © 2007 John Wiley & Sons, Ltd.
Sperm binding properties and secretory activity of the bovine oviduct immediately before and after ovulation
Authors: Sostaric Edita , Dieleman Steph J. , van de Lest Chris H.A. , Colenbrander Ben , Vos Peter L.A.M. , Garcia‐Gil Nuria , Gadella Bart M.
Published: June 2007

The possibility that differences in hormonal regimes between the two oviducts in the cow around ovulation affects secretory activity of the oviduct epithelial cells and/or sperm–oviduct binding was studied. Oviducts were collected immediately after slaughter at 6 hr before to 5 hr after timed ovulation of 14 normally cyclic cows that had been inseminated (n = 6) or not (n = 8) and material obtained from the same cows was processed in three ways. First, in vivo, after artificial insemination of the cows, low numbers of sperm cells (approx. 15 per oviduct) were found within the entire oviducts as observed by scanning electron microscopy (SEM). Almost all sperm were located in the isthmus and then only on ciliated cells and showed without exception fully matured, intact morphology. Secretory activity of noninseminated oviduct epithelia was induced after ovulation which was most predominant in the pockets of the ipsi‐lateral ampulla compared to the contra‐lateral ampulla (P < 0.01). Second, ex vivo, explants dissected from oviducts of the noniseminated cows were incubated with sperm. In all cases, the sperm bound to the explants in a similar pattern as observed in vivo and this binding was strictly fucose‐dependent. The main difference with in vivo experiments was the high numbers of sperm bound at any site of the oviduct (∼3,000 cells per mm2) indicating the high sperm binding capacity of the oviduct epithelia. Ovulation induced a striking drop in sperm binding capacity in the oviducts and was most pronounced in the isthmus (∼1,300 cells per mm2;P < 0.001) and to a lesser extent in the ampulla (∼2,000 cells per mm2,P < 0.01). Third, in vitro, pieces of tissue dissected from oviducts of the noninseminated cows were cultured to mono‐layers. Culturing epithelial cells resulted in loss of their normal morphological appearance. In all cases, the sperm binding capacity in monolayers was very low (<50 cells per mm2) when compared to corresponding explants (P < 0.0001). Sperm binding to monolayers originating from the isthmus (<25 cells per mm2) was lower than in those from the ampulla (40–50 cells per mm2;P < 0.01) and remained similar after ovulation. In all three approaches, no significant differences were found in sperm–oviduct binding characteristics and sperm‐distribution in the ipsi‐ versus contra‐lateral oviducts. This indicates, that systemic endocrine changes around ovulation rather than specific oviduct changes at the ipsi–lateral oviduct induce secretion in oviduct epithelial cells, and thus induce sperm release. Mol. Reprod. Dev. 75: 60–74, 2008. © 2007 Wiley‐Liss, Inc.
Effects of follicle size and stages of maturation on mRNA expression in bovine in vitro matured oocytes
Authors: Racedo Silvia E. , Wrenzycki Christine , Herrmann Doris , Salamone D. , Niemann Heiner
Published: June 2007

Transcription in bovine oocytes: The goal of this study was to unravel the dynamics of transcripts thought to be critically involved in oocyte maturation. The relative abundance (RA) of DYNLL1 (cytoplasmic dynein light chain LC8), DYNC1I1 (cytoplasmic dynein 1 intermediate chain), DCTN1 (dynactin 1; pGlued homolog, the activator of the cytoplasmic dynein complex 1), PMSB1 (proteasome beta subunit 1), PMSA4 (proteasome alfa subunit 4), PAP (poly‐A polymerase) and Cx43 (connexin 43) were determined by semi‐quantitative endpoint RT‐PCR at different stages of IVM, that is, GV, GVBD, MI and MII in oocytes collected from follicles of two different size categories, that is, <2 mm and 2–8 mm. The RA of DYNLL1 and DYNC1I1 were significantly higher in immature oocytes from bigger follicles than in oocytes from small follicles. Messenger RNA expression levels were similar for DCTN1, PMSB1, PMSA4, PAP, and Cx43 in the two groups during the maturation process. RA of DYNLL1, DYNC1I1 and PMSB1 decreased significantly during IVM in oocytes from follicles 2 to 8 mm. The RA for DYNLL1 was significantly higher in GVBD and MI in the oocytes from follicles 2 to 8 mm in size compared to the other group. The higher mRNA expression of DYNLL1 and DYNC1I1 and the diverging dynamics of DYNLL1, DYNC1I1, and PMSB1 mRNA expression during IVM in oocytes from the different follicle categories could be related to the developmental capacity, that is, development to blastocysts after IVF. The differences found between groups of oocytes could serve as a marker to assess the developmental capacity of bovine oocytes. Mol. Reprod. Dev. 75: 17–25, 2008. © 2007 Wiley‐Liss, Inc.
Statistical group comparison of diffusion tensors via multivariate hypothesis testing
Authors: Whitcher Brandon , Wisco Jonathan J. , Hadjikhani Nouchine , Tuch David S.
Published: May 2007

Diffusion tensor imaging (DTI) provides a powerful tool for identifying white matter (WM) alterations in clinical populations. The prevalent method for group‐level analysis of DTI is statistical comparison of the diffusion tensor fractional anisotropy (FA) metric. The FA metric, however, does not capture the full orientational information contained in the diffusion tensor. For example, the FA test is incapable of detecting group‐level differences in diffusion orientation when the level of anisotropy is unaffected. Here, we apply multivariate hypothesis testing procedures to the elements of the diffusion tensor as an alternative to univariate testing using FA. Both parametric and nonparametric tests are proposed with each choice carrying specific assumptions about the diffusion tensor model. Of particular interest is the Cramér test, which works on Euclidean interpoint distances and can be readily adapted to a specific non‐Euclidean framework by applying matrix logarithms to the diffusion tensors. Using Monte Carlo simulations, we show that multivariate tests can detect diffusion tensor principal eigenvector differences of 15 degrees with up to 80–90% power under typical design conditions. We also show that some multivariate tests are more sensitive to FA differences, when compared to a univariate test on FA, even if there is no principal eigenvector difference. The Cramér test, using the Euclidean interpoint distances, performed best under both simulation scenarios. When applying the Cramér test of the diffusion tensor in a clinical population with a history of migraine, a 169% increase was observed in the volume of a significant cluster compared to the univariate FA test. Magn Reson Med 57:1065–1074, 2007. © 2007 Wiley‐Liss, Inc.
2H double quantum filtered (DQF) NMR spectroscopy of the nucleus pulposus tissues of the intervertebral disc
Authors: Perea William , Cannella Marco , Yang Jun , Vega Alexander J. , Polenova Tatyana , Marcolongo Michele
Published: May 2007

Deuterium (2H) double‐quantum filtered (DQF) NMR spectroscopy of nucleus pulposus (NP) tissues from human intervertebral discs is reported. The DQF spectral intensities, DQ build‐up rates, and DQF‐detected rotating‐frame spin‐lattice relaxation times are sensitive to the degree of hydration of the NP tissue, and display a monotonous correlation with age between 15 and 80 years. The implications of this work are that the changes in water dynamics as detected via DQF NMR spectroscopy may be used as a probe of tissue degeneration in NP, particularly in the early stages of degeneration to which most standard NMR methods are not sensitive. Magn Reson Med 57:990–999, 2007. © 2007 Wiley‐Liss, Inc.
Self‐calibration method for radial GRAPPA/k‐t GRAPPA
Authors: Huang Feng , Vijayakumar Sathya , Li Yu , Hertel Sarah , Reza Shahed , Duensing George R.
Published: May 2007

Generalized autocalibrating partially parallel acquisitions (GRAPPA), an important parallel imaging technique, can be easily applied to radial k‐space data by segmenting the k‐space. The previously reported radial GRAPPA method requires extra calibration data to determine the relative shift operators. In this work it is shown that pseudo‐full k‐space data can be generated from the partially acquired radial data by filtering in image space followed by inverse gridding. The relative shift operators can then be approximated from the pseudo‐full k‐space data. The self‐calibration method using pseudo‐full k‐space data can be applied in both k and k‐t space. This technique avoids the prescans and hence improves the applicability of radial GRAPPA to image static tissue, and makes k‐t GRAPPA applicable to radial trajectory. Experiments show that radial GRAPPA calibrated with pseudo‐full calibration data generates results similar to radial GRAPPA calibrated with the true full k‐space data for that image. If motion occurs during acquisition, self‐calibrated radial GRAPPA protects structural information better than externally calibrated GRAPPA. However, radial GRAPPA calibrated with pseudo‐full calibration data suffers from residual streaking artifacts when the reduction factor is high. Radial k‐t GRAPPA calibrated with pseudo‐full calibration data generates reduced errors compared to the sliding‐window method and temporal GRAPPA (TGRAPPA). Magn Reson Med 57:1075–1085, 2007. © 2007 Wiley‐Liss, Inc.
Numerical calculation of grounding system in low‐frequency domain based on the boundary element method
Authors: Li Zhong‐Xin , Fan Jian‐Bin
Published: May 2007

A new mathematical model for accurately computing currents flowing along the high‐voltage ac substation's grounding system and nearby floating metallic conductors buried in the multilayer earth model has been developed in this paper, which is a hybrid of the Galerkin‐type boundary element method (BEM) and the conventional nodal analysis method. Only the propagation effect of electromagnetic waves within the substation's limited area has been neglected in this model. The quasi‐static complex image method and the closed form of Green's function are introduced into this model to accelerate the mutual impedance and induction coefficients calculation. The model is then implemented in a computer program, which can be used to calculate current distribution of any configuration of the grounding system, with or without floating metallic conductors'. Copyright © 2007 John Wiley & Sons, Ltd.
A higher‐order potential flow method for thick bodies, thin surfaces and wakes
Authors: Bernasconi D. J. , Richelsen P. M.
Published: May 2007

A higher‐order panel method for analysing the three‐dimensional potential flow fields around bodies and wakes is presented. The geometric surfaces are represented by continuous curved patches, with no discretization into panels. These geometric patches hold singularity distributions that have C2 continuity, and which are solved by applying Dirichlet or Neumann boundary conditions at discrete collocation points. While higher‐order methods have previously been developed for thick bodies and Dirichlet boundary conditions, this potential flow method is capable of modelling continuous geometry and singularity surfaces over thin bodies and wakes.

The continuous surface method has a number of advantages over conventional constant panel methods. Firstly, as curved geometries are represented exactly, changing the order of the solution does not modify the physical shape of the configuration under investigation. Furthermore, the continuous singularity distributions allow velocities to be evaluated accurately across the entire surface rather than just at collocation points. This means that pressure distributions can be calculated exactly without interpolation, and streamlines can be constructed very close to surfaces without problems of divergence. Finally, body and wake surfaces do not exhibit the strong modelling singularities that can present difficulties with wake relaxation. Copyright © 2007 John Wiley & Sons, Ltd.
Interferon‐gamma‐dependent mechanisms of mycobacteria‐induced pulmonary immunopathology: the role of angiostasis and CXCR3‐targeted chemokines for granuloma necrosis
Authors: Aly S , Laskay T , Mages J , Malzan A , Lang R , Ehlers S
Published: May 2007

The mechanisms leading to granuloma caseation, a hallmark of tuberculosis (TB) in humans, are poorly understood. Lung histopathology of C57BL/6 (WT) mice 16 weeks after aerosol infection with Mycobacterium avium strain TMC724 is uniquely characterized by centrally necrotizing granulomas, strongly resembling human TB lesions. However, IFN‐γ‐deficient (GKO) and IFN‐γ‐receptor‐deficient (GRKO) mice did not develop granuloma necrosis following M. avium infection. Comparison of differentially expressed genes in infected WT and GKO lungs by DNA microarray and RNase protection assays revealed that the angiostatic chemokines CXCL9–11 were significantly reduced in GKO mice. In contrast, angiogenic mediators such as angiopoietin and vascular endothelial growth factor, and angiogenic chemokines such as CXCL2, CCL3, and CCL4, remained unchanged or were expressed at higher levels than in infected WT mice, suggesting impaired neovascularization of the granuloma as a possible mechanism for caseation in WT mice. Granuloma vascularization was significantly decreased in central, but not peripheral, areas of granulomas of infected WT compared to GKO mice. In contrast to GRKO mice, WT mice showed signs of severe hypoxia in cells immediately surrounding the necrotic core of granulomas as measured immunohistochemically with a reagent detecting pimonidazole adducts. To test the hypothesis that CXCR3, the common receptor for the angiostatic chemokines CXCL9–11, is involved in granuloma caseation, histomorphology was assessed in M. avium‐infected mice deficient for CXCR3 (CXCR3‐KO). 16 weeks after infection, these mice developed caseating granulomas similar to WT mice. We conclude that IFN‐γ causes a dysbalance between angiostatic and angiogenic mediators and a concomitant reduction in granuloma vascularization, but that CXCR3‐targeted chemokines are not sufficient to induce granuloma necrosis in a mouse model of mycobacteria‐induced immunopathology. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The phosphatidylserine receptor mediates phagocytosis by vascular smooth muscle cells
Authors: Kolb S , Vranckx R , Huisse M‐G , Michel J‐B , Meilhac O
Published: May 2007

Apoptosis participates in every step of atherogenesis, but the process of clearance of apoptotic cells by phagocytosis has been underestimated. Rapid removal of apoptotic cells is critical for tissue homeostasis, in order to avoid accumulation of necrotic material and subsequent inflammation in the pathological vascular wall. We have demonstrated by RT–PCR, western blot and immunocytofluorescence that vascular smooth muscle cells (VSMCs) express the phosphatidylserine receptor (PSR). We then tested the involvement of PSR in the ability of VSMCs to bind and engulf apoptotic cells. We used a model of senescent erythrocytes, which expose PS after 4 days of culture (85% of cells relative to 8% in freshly isolated erythrocytes). The pseudo‐peroxidase activity of haemoglobin contained within erythrocytes allowed us to quantify per se both binding and phagocytosis by VSMCs. We have also shown by light and confocal microscopy that VSMCs were able to ingest aged erythrocytes. Addition of a blocking antibody or transfection of VSMCs by a siRNA directed against PSR reduced the binding and engulfment of aged erythrocytes by more than 90%. These results suggest that PSR is involved in phagocytosis of PS‐presenting cells. Incubation of aged erythrocytes with VSMCs also significantly increased the expression of PSR, suggesting that the tethering/ingestion of apoptotic cells triggers this process. Immunostaining for PSR in complicated atherosclerotic plaques shows positivity in the media and macrophage‐rich areas. The mechanisms underlying phagocytosis and involving PSR in vivo, within the pathological arterial wall, deserve further investigation. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Pemetrexed, a multitargeted antifolate drug, demonstrates lower efficacy in comparison to methotrexate against osteosarcoma cell lines
Authors: Bodmer N. , Walters D.K. , Fuchs B.
Published: May 2007

The folate inhibitor methotrexate (MTX) is an important component of osteosarcoma (OS) treatment regimens. New generation multitargeted antifolates, such as pemetrexed (PMX), have shown promise in the treatment of various solid tumors. In this study, the in vitro efficacy of MTX and PMX was compared in OS cell lines. MTX demonstrated a superior cytotoxic effect in comparison to PMX in all tested cell lines. Apoptosis assays revealed that both MTX and PMX induce apoptosis but MTX demonstrated superior efficacy. These in vitro results suggest that PMX as a single agent may not demonstrate improved efficacy compared to MTX in OS patients. Pediatr Blood Cancer 2008;50:905–908. © 2007 Wiley‐Liss, Inc.
NMR assignment of iso‐α‐acids from isomerised extracts of Humulus lupulus L. cones
Authors: Khatib Alfi , Wilson Erica G. , Kim Hye Kyong , Supardi Moses , Choi Young Hae , Verpoorte Robert
Published: May 2007

Iso‐α‐acids are known to contribute to the characteristic bitter taste of beer. Six iso‐α‐acids were isolated from a carbon dioxide extract of the cones of Humulus lupulus L. by centrifugal partition chromatography followed by separation through β‐cyclodextrin binding. This method overcame the low yield issue of most isolation procedures that results from the low stability of these compounds to light and oxygen. Their full identification was performed using one‐ and two‐dimensional NMR spectrometry, including 1H‐ and 13C‐NMR, 1H‐1H COSY, HMQC and HMBC and electrospray ionisation mass spectrometry. The results confirmed the structures of the isolated compounds as trans‐isocohumulone, cis‐isocohumulone, trans‐isohumulone, cis‐isohumulone, trans‐isoadhumulone and cis‐isoadhumulone. Epimers can be easily distinguished by observing the chemical shift differences of the H‐5, H‐1′″, H‐2′″ and C‐5 signals and the different splitting pattern of H‐5 and H‐2″. Copyright © 2007 John Wiley & Sons, Ltd.
Could ovarian choriocarcinoma be detected by maternal serum screening for Down syndrome?
Authors: Gauchez Anne‐Sophie , Dreux Sophie , Stéfani Laetitia , Mousseau Mireille , Jouk Pierre‐Simon , Muller Françoise
Published: May 2007

The incidence of ovarian malignancies during gestation ranges from 1 in 8000 to 1 in 20 000 deliveries. Ovarian malignancies that produce human chorionic gonadotropin (hCG) are limited to germ cell tumors, of which dysgerminoma is the most frequent (45%) malignant type encountered in pregnant patients, the others being ovarian choriocarcinoma and mixed germ cell tumors (Boulay and Podczaski, 1998). In women of childbearing age, it is hard to distinguish between metastatic choriocarcinoma on a complete mole and primary ovarian choriocarcinoma. Treatment is based on adnexectomy followed by chemotherapy. Given the extreme rarity of these tumors, the long‐term prognosis is difficult to establish. Had the diagnosis for our patient been made during pregnancy, the therapeutic approach would have been discussed in terms of gestational age. In the last trimester, we could have suggested cesarean section followed by adnexectomy, and then chemotherapy. In the second‐trimester, chemotherapy could have been discussed, although the fetal toxicity of cisplatin chemotherapy is not firmly defined (Ferrandina et al., 2005). This treatment is an alternative to termination of pregnancy. We retrospectively studied maternal serum biochemistry so as to assess the possibility of a diagnosis of ovarian choriocarcinoma at the time of maternal serum screening for Down syndrome. Copyright © 2007 John Wiley & Sons, Ltd.
Mechanism of a one‐step method for preparing silane grafting and cross‐linking polypropylene
Authors: Yang Shujing , Song Guojun , Zhao Yunguo , Yang Chao , She Xilin
Published: May 2007

A high‐melt‐strength polypropylene (HMSPP) with partially cross‐linking, modified from a normal isotactic polypropylene (IPP), is prepared by a one‐step silane grafting and cross‐linking method in a twin‐screw reactive extruder. The melt grafting and cross‐linking of IPP is achieved by using vinyl unsaturated silane with long chain as a grafting monomer, benzoyl peroxide (BPO) as an initiator, styrene as a coagent, and a little water as a catalyst for cross‐linking. By analyzing the difference of the Fourier transformed infrared spectra between raw and modified PP, comparing the variety of the melt flow rate (MFR) and gel percentage between cured and uncured PP samples, and investigating the effect of catalyst on the MFR and gel percentage of modified PP, the partially cross‐linked polypropylene in the way of one‐step reactive extrusion has been verified. We put forward the reactive mechanism of one‐step method based on our experimental results. In this mechanism, the hydrolysis and condensation of silane occur first through the catalysis of water and a compound with two or more double‐bond is formed, which then the compound reacts with PP macroradicals to form the partially cross‐linked PP. POLYM. ENG. SCI., 47:1004–1008, 2007. © 2007 Society of Plastics Engineers
The rheological and physical properties of linear and branched polypropylene blends
Authors: McCallum Tara J. , Kontopoulou Marianna , Park Chul B. , Muliawan Edward B. , Hatzikiriakos Savvas G.
Published: May 2007

The rheological, thermal, and mechanical properties of blends consisting of a linear high melt flow rate polypropylene (PP) and two branched PPs are characterized in detail. Blends containing branched PPs display evidence of miscibility in the melt state and exhibit high melt elasticity together with significant strain hardening in extensional deformation while retaining good flow properties. Out of the two blend systems examined the blends containing linear and branched PPs with similar melt flow rates have better mechanical properties, higher crystallization temperatures, and higher crystallinities. POLYM. ENG. SCI., 47:1133–1140, 2007. © 2007 Society of Plastics Engineers
Synthesis, characterization, mechanical properties and biocompatibility of interpenetrating polymer network–super‐porous hydrogel containing sodium alginate
Authors: Yin Lichen , Fei Likun , Tang Cui , Yin Chunhua
Published: May 2007

In this investigation an interpenetrating polymer network–superporous hydrogel containing sodium alginate (IPN‐SPHAlg) was synthesized. The morphology of the polymer was characterized using scanning electron microscopy, light images and porosity, and the polymer was further examined by swelling ratio, mechanical strength and biocompatibility. The results indicated that the IPN‐SPHAlg possessed both large numbers of interconnected pores and an interpenetrating network. The swelling ratio of IPN‐SPHAlg was lower than that of the superporous hydrogel (SPH) and it decreased as the sodium alginate/monomer ratio increased. The IPN‐SPHAlg exhibited pH responsiveness and salt‐sensitive properties. Compared to SPH and SPH composites, the mechanical strength of IPN‐SPHAlg was significantly enhanced. Thiazolyl blue assay on AD293 cells, in situ lactate dehydrogenase assay and morphological study of rat intestine showed that the polymer induced no significant cell or mucosal damage. The fast swelling, good mechanical properties, pH sensitivity and biocompatibility of the IPN‐SPHAlg suggested it as a potential candidate in the field of drug‐delivery systems. Copyright © 2007 Society of Chemical Industry
Synthesis and characterization of novel π‐conjugated polymers with phosphole ring derivatives
Authors: Na Hai‐Sub , Morisaki Yasuhiro , Aiki Yasuhiro , Chujo Yoshiki
Published: June 2007

Novel π‐conjugated polymers (8–10) were prepared by the palladium‐catalyzed Sonogashira coupling reaction of three kinds of phosphole‐ring‐containing monomers with 2,5‐dihexyloxyl‐1,4‐diethynylbenzene. The obtained polymers (8–10) were regioregulated with the 2,5‐substituted phosphole ring in the polymer main chain and characterized with 1H, 13C, and 31P NMR and FTIR. Polymers 8–10 were found to have an extended π‐conjugated system according to the results of UV–vis absorption spectra. In the fluorescence emission spectra of 8–10, moderate emission peaks were observed in the visible blue‐to‐green region. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2867–2875, 2007
Synthesis and photophysical properties of Rhodamine B dye‐bearing poly(isobutyl methacrylate‐co‐2,2,2‐trifluoroethyl methacrylate) as a temperature‐sensing polymer film
Authors: Obata Makoto , Morita Mako , Nakase Kayoko , Mitsuo Kazunori , Asai Keisuke , Hirohara Shiho , Yano Shigenobu
Published: June 2007

To develop a novel temperature‐sensitive paint, methacrylamide monomers bearing Rhodamine B dye (two regioisomers, 3a and 3b) were synthesized and polymerized with isobutyl methacrylate and 2,2,2‐trifluoroethyl methacrylate to afford Rhodamine B‐pendant polymers 4a and 4b. The methacrylamide monomers 3a and 3b showed photophysical properties almost identical with those of Rhodamine B. The temperature sensitivity of the luminescence intensity of 3a and 3b was also similar to that of Rhodamine B. The polymers 4a and 4b have excellent solubility in nonpolar organic solvents and are suitable for application as paint. Films of polymers 4a and 4b showed temperature‐dependent luminescence, which is applicable for temperature‐sensing. The temperature sensitivity of the film of 4a was estimated to be −0.37% °C−1, and was independent of pressure. The film of 4b showed higher temperature sensitivity, but its temperature sensitivity was slightly pressure‐dependent. Hence, polymer 4a is expected to be superior for practical use in paints having temperature‐sensing functionality. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2876–2885, 2007
Modular synthesis of ABC type block copolymers by “click” chemistry
Authors: Opsteen Joost A. , van Hest Jan C. M.
Published: June 2007

Heterotelechelic polystyrene (PS), poly(tert‐butyl acrylate) (PtBA), and poly (methyl acrylate) (PMA), containing both azide and triisopropylsilyl (TIPS) protected acetylene end groups, were prepared in good control (Mw/Mn ≤ 1.24) by atom transfer radical polymerization (ATRP). The end groups were independently applied in two successive “click” reactions, that is: first the azide termini were functionalized and, after deprotection, the acetylene moieties were utilized for a second conjugation step. As a proof of concept, PS was consecutively functionalized with propargyl alcohol and azidoacetic acid, as confirmed by MALDI‐ToF MS. In addition, the same methodology was employed to modularly build up an ABC type triblock terpolymer. Size exclusion chromatography measurements demonstrated first coupling of PtBA to PS and, after the deprotection of the acetylene functionality on PS, connection of PMA, yielding a PMA‐b‐PS‐b‐PtBA triblock terpolymer. The reactions were driven to completion using a slight excess of azide functionalized polymers. Reduction of the residual azide groups into amines allowed easy removal of this excess of polymer by column chromatography. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2913–2924, 2007