bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrothermal Synthesis, Structural Characterisations, and Photoluminescence Properties of Four Inorganic‐Organic Hybrid Compounds in the Indium/Gallium Iodate Family
Authors: Liu Xiaomin , Li Guanghua , Hu Bin , Yu Yang , Hu Yawei , Bi Minghui , Shi Zhan , Feng Shouhua
Published: April 2008

Four inorganic‐organic hybrid compounds with the formulae In2(IO3)6(H2O)(2,2′‐bipy)·H2O (1), In2(IO3)6(H2O)(1,10‐phen)·H2O (2), Ga(IO3)3(2,2′‐bipy)·HIO3 (3) and Ga(IO3)3(1,10‐phen)·H2O (4) were hydrothermally synthesised at 100 °C over 7 d and subsequently characterised by single‐crystal X‐ray diffraction. The bidentate diamine ligands 2,2′‐bipy and 1,10‐phen in the In/I/O system give rise to the compounds In2(IO3)6(H2O)(2,2′‐bipy)·H2O and In2(IO3)6(H2O)(1,10‐phen)·H2O which crystallise in the monoclinic space group P21/c. Using the same bidentate diamine ligands, namely 2,2′‐bipy and 1,10‐phen, in the Ga/I/O system led to the formationof Ga(IO3)3(2,2′‐bipy)·HIO3 and Ga(IO3)3(1,10‐phen)·H2O which crystallise in the monoclinic space group P21/n. Both, In2(IO3)6(H2O)(2,2′‐bipy)·H2O and In2(IO3)6(H2O)(1,10‐phen)·H2O possess 2D layered structures, with the former consisting of [In(H2O)(IO3)5]2– clusters and [In(IO3)(2,2′‐bipy)]2+ chains and the latter consisting of [In(H2O)(IO3)5]2– clusters and [In(IO3)(1,10‐phen)]2+ chains. Compound Ga(IO3)3(2,2′‐bipy)·HIO3 is a 1D ribbon built up from [IO3] pyramids, [GaO4N2] octahedra and distinct [I2O6] units and featuring interesting left and right helical chains. Compound Ga(IO3)3(1,10‐phen)·H2O has a 1D chain‐like structure constructed from the alternation of [GaO4N2] octahedra and [IO3] pyramids. By comparatively studying the photoluminescence properties of these compounds, we may conclude that the photoluminescence originates from ligand‐centred π‐π* transitions. The synthesised products were further characterised by powder X‐ray diffraction, thermogravimetric analysis, IR spectroscopy, ICP and elemental analysis.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Palladium‐Catalyzed Hydrostannylation of α‐Heteroalkynes and Alkynyl Esters in Ionic Liquids
Authors: Cai Mingzhong , Wang Yongguang , Hao Wenyan
Published: April 2008

Palladium‐catalyzed hydrostannylation reactions of α‐heteroalkynes and alkynyl esters were achieved with high regio‐ and stereoselectively in the ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim][PF6]) at 60 °C in high yields. Our system not only avoids the use of highly toxic benzene or volatile THF as solvent but also solves the basic problem of palladium catalyst reuse.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Applicability of pushover methods for the seismic analysis of single‐column bent viaducts
Authors: Isaković Tatjana , Lazaro Mauro Pompeyo Nino , Fischinger Matej
Published: April 2008

An overview of the applicability of a typical single‐mode pushover method (the N2 method) and two typical multi‐mode pushover methods (the modal pushover analysis (MPA) and incremental response spectrum analysis (IRSA) methods) for the analysis of single column bent viaducts in the transverse direction is presented. Previous research, which was limited to relatively short viaducts supported by few columns, has been extended to longer viaducts with more bents.

The single‐mode N2 method is accurate enough for bridges where the effective modal mass of the fundamental mode is at least 80% of the total mass. The applicability of this method depends on (a) the ratio of the stiffness of the superstructure to that of the bents and (b) the strength of the bents. In short bridges with few columns, the accuracy of the N2 method increases as the seismic intensity increases, whereas in long viaducts (e.g. viaducts with lengths greater than 500 m) the method is in general less effective.

In the case of the analyzed moderately irregular long viaducts, which are common in construction design practice, the MPA method performed well. For the analysis of bridges where the modes change significantly, depending on the seismic intensity, the IRSA method is in principle more appropriate, unless a viaduct is torsionally sensitive. In such cases, all simplified methods should be used with care. Copyright © 2008 John Wiley & Sons, Ltd.
Fabrication of drug‐loaded electrospun aligned fibrous threads for suture applications
Authors: He Chuang‐Long , Huang Zheng‐Ming , Han Xiao‐Jian
Published: April 2008

In this work, drug‐loaded fibers and threads were successfully fabricated by combining electrospinning with aligned fibers collection. Two different electrospinning processes, that is, blend and coaxial electrospinning, to incorporate a model drug tetracycline hydrochloride (TCH) into poly(L‐lactic acid) (PLLA) fibers have been used and compared with each other. The resulting composite ultrafine fibers and threads were characterized through scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, differential scanning calorimetry, and tensile testing. It has been shown that average diameters of the fibers made from the same polymer concentration depended on the processing method. The blend TCH/PLLA fibers showed the smallest fiber diameter, whereas neat PLLA fibers and core‐shell TCH‐PLLA fibers showed a larger proximal average diameter. Higher rotating speed of a wheel collector is helpful for obtaining better‐aligned fibers. Both the polymer and the drug in the electrospun fibers have poor crystalline property. In vitro release study indicated that threads made from the core‐shell fibers could suppress the initial burst release and provide a sustained drug release useful for the release of growth factor or other therapeutic drugs. On the other hand, the threads from the blend fibers produced a large initial burst release that may be used to prevent bacteria infection. A combination of these results suggests that electrospinning technique provides a novel way to fabricate medical agents‐loaded fibrous threads for tissue suturing and tissue regeneration applications. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Directional conductivity in SWNT‐collagen‐fibrin composite biomaterials through strain‐induced matrix alignment
Authors: Voge Christopher M. , Kariolis Mihalis , MacDonald Rebecca A. , Stegemann Jan P.
Published: April 2008

Composite biomaterials incorporating fibroblast cells, collagen Type I, fibrin, and 2 wt % carboxylated SWNT were created, and their properties were compared with similar control constructs without SWNT. Alignment of the matrix was stimulated by application of 8% cyclic strain for three 12‐h periods over three days. All constructs underwent cell‐mediated gel compaction to 15–20% of their initial volume, which was not affected by SWNT loading. Mechanical strain increased the rate of compaction, and strained constructs were significantly more compacted than unstrained controls by day 3. Cell viability and morphology were similar in both control and SWNT‐loaded constructs, but unstrained samples exhibited a more stellate appearance with more numerous cellular projections. Application of mechanical strain caused clear alignment of both the cells and matrix in the direction of the applied strain. Bioimpedance measurements showed that SWNT loading increased the electrical conductivity of composite constructs, and that mechanically‐induced alignment of the matrix/SWNT caused a further increase in conductivity. These results demonstrate that SWNT can be used to augment the electrical properties of 3D protein hydrogels, and that anisotropy in the matrix further enhances these properties. Such electrically conductive biopolymers may have a variety of applications in tissue engineering and biosensor development. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Almost regular edge colorings and regular decompositions of complete graphs
Authors: Bryant Darryn , Maenhaut Barbara
Published: April 2008

For k = 1 and k = 2, we prove that the obvious necessary numerical conditions for packing t pairwise edge‐disjoint k‐regular subgraphs of specified orders m1,m2,… ,mt in the complete graph of order n are also sufficient. To do so, we present an edge‐coloring technique which also yields new proofs of various known results on graph factorizations. For example, a new construction for Hamilton cycle decompositions of complete graphs is given. © 2008 Wiley Periodicals, Inc. J Combin Designs 16: 499–506, 2008
Zidovudine with nevirapine for the prevention of HIV mother‐to‐child transmission reduces nevirapine resistance in mothers from the Western Cape, South Africa
Authors: van Zyl G.U. , Claassen M. , Engelbrecht S. , Laten J.D. , Cotton M.F. , Theron G.B. , Preiser W.
Published: April 2008

In the Western Cape province of South Africa, an intensified regimen for the prevention‐of‐mother‐to‐child‐transmission‐of‐HIV consisting of zidovudine (AZT) from 34 weeks of pregnancy plus single dose (sd) nevirapine (NVP) during labor was instituted in 2004. The newborn baby receives a single dose of NVP and AZT for 7 days. Similar strategies in Thailand and Africa have been shown to be more effective in reducing transmission than NVP alone. The use of sd NVP only for the prevention‐of‐mother‐to‐child‐transmission‐of‐HIV has a high risk of inducing resistance (25–69%) with an average of 35.7% by a recent meta‐analysis and has been shown to adversely affect non‐nucleoside reverse transcriptase inhibitor (NNRTI)‐based antiretroviral therapy when initiated within 6 months. In this study the prevalence of resistance to NVP and AZT in mothers who had received the intensified regimen was measured. Specimens collected from mothers were genotyped by in‐house PCR and sequencing. In specimens obtained within 60 days of delivery, acquired NVP resistance mutations were detected in 13 of 76 patients (17.1%, 95% confidence interval: 8.7–25.6%), which appears to be lower than in studies with sd NVP alone (37.5%, 95% confidence interval: 23.0–50.6%). J. Med. Virol. 80:942–946, 2008. © 2008 Wiley‐Liss, Inc.
Crimean‐Congo hemorrhagic fever in Pakistan
Authors: Rai Mohammad A. , Khanani Mohammad R. , Warraich Haider J. , Hayat Abbas , Ali Syed H.
Published: April 2008

Crimean‐Congo virus, the causative agent of Crimean‐Congo Virus Fever (CCVF) is endemic in Pakistan. Cases are documented sporadically ever year, mostly at and around the time of Eid‐ul‐Adha, an Islamic festival, celebrated on day 10 through 13 of the 12th month of each lunar calendar year. At this time of the year in Pakistan, livestock are brought down to the urban areas from the rural parts of the country. Animals are housed in open spaces and private houses until they are slaughtered during the 3 days of Eid‐ul‐Adha. This allows the CCHF virus, which is carried by a tick that inhabits the animal hide, to be transmitted through unprotected contact with live animals as well as through contact with animal blood subsequent to its slaughter. In this report, a typical case of CCVF is described that was encountered in Rawalpindi, Pakistan. A number of issues pertaining to the management of recurrent outbreaks of CCVF in the country are discussed. J. Med. Virol. 80:1004–1006, 2008. © 2008 Wiley‐Liss, Inc.
Cervical and oral human papillomavirus types in HIV‐1 positive and negative women with cervical disease in South Africa
Authors: Marais Dianne J. , Passmore Jo‐Ann S. , Denny Lynette , Sampson Candice , Allan Bruce R. , Williamson Anna‐Lise
Published: April 2008

This study tested cervical and oral human papillomavirus (HPV) infection in HIV‐1 seropositive (HIV+) and seronegative (HIV−) women to determine any association between infections at both sites and the difference in prevalence of the HPV types infecting these women. Participants were 115 women referred to a colposcopy clinic after diagnosis of abnormal cervical cytology. The women showed low grade cervical intraepithelial neoplasia (CIN1) or high grade disease (CIN2/3) or no CIN based on colposcopy and histology. Typing of HPV in cervical and oral cells was by Roche linear array and included direct sequencing on selected oral samples. Cervical HPV prevalence was 86.5% and 97.1% in HIV− and HIV+ women respectively. With the exception of HPV‐45, prominent in HIV+ women, the hierarchy of predominant types were similar in HIV− and HIV+ women. HPV‐16 was most prevalent in both HIV+ (41.7%) and HIV− women (38.5%) with CIN2/3. Significantly more HIV+ women had multiple cervical (>1) infections than HIV− women (36.1% vs. 88.2%, P < 0.001) and more oral HPV infections (45.5% and 25% respectively; P = 0.04). The most prevalent oral HPV types were HPV‐33, ‐11, and ‐72. The majority of women did not have concordant oral and cervical HPV types, reflecting possible independence of infection at the two sites. HIV immune suppression did not impact significantly on the predominant types of cervical HPV infection (except for HPV‐45). HIV+ women had more multiple HPV infections and those with severe cervical disease a similar prevalence of HIV‐16 but a lower HPV‐18 prevalence than HIV− women. J. Med. Virol. 80:953–959, 2008. © 2008 Wiley‐Liss, Inc.
Monitoring of adenovirus from conjunctival scrapings in Japan during 2005–2006
Authors: Matsui Kiyohiko , Shimizu Hideaki , Yoshida Atsushi , Nagaoka Emi , Nishio Osamu , Okuda Kenji
Published: April 2008

A total of 189 conjunctival scrapings were collected from patients in Tokyo, Japan by monitoring adenovirus infection in community‐based clinics during 2005 and 2006. Of the 189 samples, 155 (82%) had adenoviruses detected by polymerase chain reaction (PCR). The serotypes were determined by PCR‐restriction fragment length polymorphism (PCR‐RFLP) analysis, using a combination of endonucleases, such as HhaI, AluI, and HaeIII, and neutralization tests (NTs). PCR‐RFLP identified five serotypes: serotype 3: 16.8%, serotype 4: 9.7%, serotype 8: 34.8%, serotype 11: 23.2%, and serotype 37: 15.5%. Adenovirus 8 was the most common serotype identified. A subset consisting of 25 isolates identified as adenovirus 8 from this study plus 25 isolates from Kawasaki were analyzed using PCR sequencing of the hexon gene. Compared with prototype adenovirus serotype 8 and serotype 9 derived in Tokyo and Kawasaki, these isolates shared 61.7–62.8% and 80.5–82.7% amino acid homology, respectively, suggesting that a variant adenovirus serotype 8 was involved in this outbreak, and is different from the prototype adenovirus 8 virus. This variant had not been detected in Japan prior to 1996 and appears to be the most common adenovirus type 8 involved in cases of epidemic keratoconjunctivitis in Japan at present. J. Med. Virol. 80:997–1003, 2008. © 2008 Wiley‐Liss, Inc.
What is the role of serology for the study of chronic hepatitis B virus infection in the age of molecular biology?
Authors: Galli Claudio , Orlandini Elisa , Penzo Luigi , Badiale Renzo , Caltran Giacomo , Valverde Sara , Gessoni Gianluca
Published: April 2008

To assess quantitative serology in chronic hepatitis B virus (HBV) infection, testing by novel immunoassays has been carried out on 202 specimens from untreated patients and in 83 samples from 10 patients with chronic hepatitis B treated with lamivudine. Serum samples were assayed for quantitative HBsAg, in comparison with quantitative HBV‐DNA, and for anti‐HBc IgM and the avidity index (AI) of total anti‐HBc antibodies. The AI was high (mean: 0.93 ± 0.19) in all groups, confirming the consistency of this procedure in chronic HBV infections. A low‐level positivity (2–28 Paul‐Ehrlich units/ml) for IgM anti‐HBc was detectable both in HBeAg‐positive and in HBeAg‐negative untreated chronic hepatitis cases (mean S/CO values by the Abbott Architect assay: 0.51 ± 0.12 and 0.48 ± 0.10, respectively; correlation between assays: r = 0.685), while treated patients (mean: 0.20 ± 0.15) and inactive carriers (mean: 0.17 ± 0.21), were generally negative for IgM. The levels of HBsAg (IU/ml) showed a weak correlation with HBV‐DNA (IU/ml). A difference in HBsAg levels was found between inactive carriers (1,935 ± 2,887 IU/ml) and chronic hepatitis B cases, either treated (5,199 ± 9,259 IU/ml) or untreated (14,596 ± 15,227 IU/ml). Pre‐treatment levels of HBsAg in patients undergoing lamivudine treatment were correlated with a sustained response to therapy over 13–33 months (mean: 27.3) of follow‐up: mean HBsAg values were 1,576 + 1,487 IU/ml in five responders and 6,063 + 5,142 in five nonresponders or breakthrough responders (P < 0.05). The availability of standardized quantitative immunoassays for HBsAg and anti‐HBc IgM may be considered in addition to quantitative HBV‐DNA in the staging and monitoring of chronic HBV infection. J. Med. Virol. 80:974–979, 2008. © 2008 Wiley‐Liss, Inc.
Human cytomegalovirus and Epstein–Barr virus in apical and marginal periodontitis: A role in pathology?
Authors: Sunde Pia Titterud , Olsen Ingar , Enersen Morten , Beiske Klaus , Grinde Bjørn
Published: April 2008

Periodontitis is presumably caused by bacterial infection, but it has been shown recently that affected tissue often contains human cytomegalovirus (HCMV) and Epstein–Barr virus (EBV). The present study was initiated to evaluate the role of these viruses in the pathogenesis of periodontitis. HCMV and EBV were quantified in 40 apical and 25 marginal periodontitis samples using real time PCR. In situ hybridization or immunohistochemistry was carried out on apical samples to detect viral presence within cells. A possible association with relevant bacteria was examined. Of the apical periodontitis samples, 50% contained EBV, while none contained HCMV. Of the marginal periodontitis samples, 40% were positive for EBV and 12% for HCMV. With one exception, however, the amount of virus was close to the detection limits. EBV was only detected in 1 out of 15 healthy periodontium samples. Immunohistochemistry and in situ hybridization were all negative. Significant associations were found between periodontal EBV and the presence of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Although there was an obvious association of the virus with clinical samples, it seems unlikely that these viruses play a major role in the pathogenesis of periodontitis of the average patient. Their presence may reflect that the clinical samples contain more blood or saliva compared to controls, or an accumulation of lymphoid cells harboring virus in the inflamed tissue. J. Med. Virol. 80:1007–1011, 2008. © 2008 Wiley‐Liss, Inc.
Improvement in the tribological properties of imidazolium‐derived ionic liquids by additive technology
Authors: Minami Ichiro , Watanabe Naoko , Nanao Hidetaka , Mori Shigeyuki , Fukumoto Kenta , Ohno Hiroyuki
Published: April 2008

Molecular design of wear‐preventing and friction‐reducing additives for ionic liquids is described. The tribological properties of carboxylic acid‐derived additives were evaluated by a ball‐on‐flat type tribotest under reciprocating motion. Tetraalkylammonium and tetraalkylphosphonium salts of N‐benzyl‐protected aspartic acid were dissolved in 1‐alkyl‐3‐methylimidazolium‐derived ionic liquids. They prevented wear remarkably and reduced friction fairly. Influences of alkyl group in imidazolium molecule on additive response were observed. In tetraalkylammonium‐derived ionic liquids, the additive reduced wear but did not reduce friction under these conditions. The salt of N‐acetyl‐protected glutamic acid prevented wear, but did not reduce friction. Copyright © 2008 John Wiley & Sons, Ltd.
Deconvolution of electrokinetic and chromatographic contributions to solute migration in stereoselective ion‐exchange capillary electrochromatography on monolithic silica capillary columns
Authors: Preinerstorfer Beatrix , Lämmerhofer Michael , Hoffmann Christian V. , Lubda Dieter , Lindner Wolfgang
Published: April 2008

A monolithic silica stationary phase functionalized with an enantioselective strong cation exchanger based on an aminosulfonic acid derivative was used for chiral separations of basic test solutes by nonaqueous CEC and capillary LC. The effects of the applied electric field as well as the ionic strength in the eluent on electrokinetic and chromatographic contributions to the overall separation performance in the electrically driven mode were investigated. Hence, under the utilized experimental conditions, i. e., at an electric field strength in the range of ∼︁120–720 V/cm (applied voltages 4–24 kV) and an ionic strength of the counterion between 5 and 25 mM (at constant acid‐to‐base, i. e., co‐ to counterion ratio of 2:1), no deviations from the expected linearity of the EOF were observed. This led to the conclusion that an occurrence of the so‐called electrokinetic effects of the second kind resulting from electric double layer overlap inside the mesopores of the monolithic stationary phase and concentration polarization phenomena were largely negligible. Additional support to this conclusion was inferred from the observed independence of CEC retention factors on the electric field strength across the investigated ionic strength range of the BGE. As a consequence, a simple framework allowing for calculation of the CEC mobilities from the individual separation contributions, viz. electroosmotic and electrophoretic mobilities as well as retention factors, could be applied to model CEC migration. There was a reasonable agreement between calculated and experimental CEC mobility data with deviations typically below 5%. The deconvolution of the individual contributions to CEC migration and separation is of particular value for the understanding of the separation processes in which electrophoretic migration of ionic sample constituents plays a significant role like in ion‐exchange CEC and may aid the optimization procedure of the BGE and other experimental conditions such as the optimization of the surface chemistry of the stationary phase. In combination with the remarkable column performance evident from the low theoretical plate heights observed under CEC conditions for all test solutes (3.5–7.5 μm in the flow rate range of 0.4–1.2 mm/s, corresponding to (130 000–300 000 plates per meter), the presented framework provides an attractive tool as the basis for the assessment of chromatographic selectivities in a miniaturized CEC screening of new selectors and chiral stationary phases (CSPs), respectively, from experimental CEC data and known CE mobilities.
In‐line coupling of a reversed‐phase column to cope with limited chemoselectivity of a quinine carbamate‐based anion‐exchange type chiral stationary phase
Authors: Sardella Roccaldo , Lämmerhofer Michael , Natalini Benedetto , Lindner Wolfgang
Published: April 2008

A chiral stationary phase based on tert‐butylcarbamoyl quinine has shown remarkable enantiomer separation capability for the thyroid hormone thyroxine (T4) and its structural analogue triiodothyronine (T3) employing hydroorganic buffered mobile phases (typical RP conditions). To overcome the problem of a somehow limited chemoselectivity for the critical peak pair between adjacent L‐thyroxine (L‐T4) and D‐thyroxine (D‐T4) peaks on the chiral anion‐exchanger CSP when all four compounds need to be analysed simultaneously like in impurity profiling of L‐T4 drug products, an RP column (Gemini C18) was serially coupled with the chiral anion‐exchanger column to add a hydrophobic selectivity increment and to improve thereby the critical resolution between L‐T3 and D‐T4. Various parameters such as organic modifier content, pH, buffer concentration and type, type of achiral column as well as sequence of achiral and chiral column have been investigated with individual and tandem columns. With the optimized conditions and use of the tandem column a significantly improved separation, as compared to the chiral anion‐exchanger column alone, with a critical resolution as high as 3.7 and an almost equal band spacing of the four components of the test mixture could be obtained. The sequence of the columns (achiral–chiral or chiral–achiral) had no significant effect on the separation performance.
Hydrophilic interaction chromatography of small metal species in plants using sulfobetaine‐ and phosphorylcholine‐type zwitterionic stationary phases
Authors: Weber Günther , von Wirén Nicolaus , Hayen Heiko
Published: April 2008

Hydrophilic interaction chromatography (HILIC) was applied for the separation of small, noncovalent metal species, and free ligands in plants, using two different zwitterionic stationary phases at pH 7.3. Ligands ranged from amino acids and phytosiderophores to organic acids and synthetic chelators like EDTA. Our results confirmed the suitability of zwitterionic stationary phases for the separation of such ligands and their metal complexes. In particular, the chromatographic behavior of phytosiderophore complexes of copper, nickel, and zinc on a sulfobetaine‐type material was compared to that on a phosphorylcholine‐type material under otherwise identical conditions. A compression of the usable retention range for phytosiderophore species on the latter phase was found, which can be traced back to the reversed charge orientation of the zwitterionic functionalities. Differences were also found for the integrity of more labile metal chelates during separation on the two columns. In particular, Ni–malate could only be analyzed on the sulfobetaine phase, and Cu–glutathione, Ni–aspartate, and Ni–citrate complexes were only stable on the phosphorylcholine stationary phase at pH 7.3. Ni–histidine species were only found after lowering the pH to 4–5. The identification of separated species is possible by online ESI‐MS in the negative ionization mode.
Nonlinear surface plasmon polaritonic crystals
Authors: Wurtz G.A. , Zayats A.V.
Published: April 2008

We present an overview of the optical properties of nonlinear surface plasmon polaritonic crystals and their applications to control light with light. Surface plasmon polaritonic crystals are periodically nanostructured metal surfaces or thin metal films that act as two‐dimensional photonic crystals for surface polaritons. Hybritization of such nanostructures with dielectrics exhibiting an optical nonlinear response allows utilization of the electromagnetic field enhancement effects to observe nonlinear effects and bistable behaviour at low light intensities. By changing the geometry of the nanostructured film, the dispersion of the crystal is modified and, thus, electromagnetic mode structure and associated density of states can be controllably tuned in the desired spectral range. This provides enhanced flexibility in engineering the nonlinear optical response of plasmonic crystals in a chosen spectral range for both control and signal wavelengths.
Feasibility of using limited‐population‐based arterial input function for pharmacokinetic modeling of osteosarcoma dynamic contrast‐enhanced MRI data
Authors: Wang Ya , Huang Wei , Panicek David M. , Schwartz Lawrence H. , Koutcher Jason A.
Published: April 2008

For clinical dynamic contrast‐enhanced (DCE) MRI studies, it is often not possible to obtain reliable arterial input function (AIF) in each measurement. Thus, it is important to find a representative AIF for pharmacokinetic modeling of DCE‐MRI data when individual AIF (Ind‐AIF) measurements are not available. A total of 16 patients with osteosarcomas in the lower extremity (knee region) underwent multislice DCE‐MRI. Reliable Ind‐AIFs were obtained in five patients with a contrast injection rate of 2 cc/s and another five patients with a 1 cc/s injection rate. Average AIF (Avg‐AIF) for each injection rate was constructed from the corresponding five Ind‐AIFs. For each injection rate there are no statistically significant differences between pharmacokinetic parameters of the five patients derived with Ind‐AIFs and Avg‐AIF. There are no statistically significant changes in pharmacokinetic parameters of the 16 patients when the two Avg‐AIFs were applied in kinetic modeling. The results suggest that it is feasible, as well as practical, to use a limited‐population‐based Avg‐AIF for pharmacokinetic modeling of osteosarcoma DCE‐MRI data. Further validation with a larger population and multiple regions is desirable. Magn Reson Med 59:1183–1189, 2008. © 2008 Wiley‐Liss, Inc.
3D hyperpolarized He‐3 MRI of ventilation using a multi‐echo projection acquisition
Authors: Holmes James H. , O'Halloran Rafael L. , Brodsky Ethan K. , Jung Youngkyoo , Block Walter F. , Fain Sean B.
Published: April 2008

A method is presented for high‐resolution 3D imaging of the whole lung using inhaled hyperpolarized (HP) He‐3 MR with multiple half‐echo radial trajectories that can accelerate imaging through undersampling. A multiple half‐echo radial trajectory can be used to reduce the level of artifact for undersampled 3D projection reconstruction (PR) imaging by increasing the amount of data acquired per unit time for HP He‐3 lung imaging. The point spread functions (PSFs) for breath‐held He‐3 MRI using multiple half‐echo trajectories were evaluated using simulations to predict the effects of T2* and gas diffusion on image quality. Results from PSF simulations were consistent with imaging results in volunteer studies showing improved image quality with increasing number of echoes using up to 8 half‐echoes. The 8‐half‐echo acquisition is shown to accommodate lost breath‐holds as short as 6 sec using a retrospective reconstruction at reduced resolution and also to allow reduced breath‐hold time compared with an equivalent Cartesian trajectory. Furthermore, preliminary results from a 3D dynamic inhalation‐exhalation maneuver are demonstrated using the 8‐half‐echo trajectory. Results demonstrate the first high‐resolution 3D PR imaging of ventilation and respiratory dynamics in humans using HP He‐3 MR. Magn Reson Med 59:1062–1071, 2008. © 2008 Wiley‐Liss, Inc.
Quantitative J‐resolved prostate spectroscopy using two‐dimensional prior‐knowledge fitting
Authors: Lange Thomas , Schulte Rolf F. , Boesiger Peter
Published: April 2008

Two‐dimensional (2D) prior‐knowledge fitting (ProFit) was adapted and applied for the quantification of J‐resolved (JPRESS) spectra acquired at a field strength of 3T from the human prostate in vivo. In contrast to methods based on simple line fitting and peak integration, commonly applied for metabolite quantification in the prostate, ProFit yields metabolite concentration ratios that are independent of sequence and field strength, since it is based on the linear combination of 2D basis spectra. It is demonstrated that ProFit benefits from the increased information content and reduced baseline distortion in JPRESS prostate spectra, in particular for the quantification of coupled metabolites like citrate (Cit), spermine (Spm), and myo‐inositol (mI). The method is validated with 10 repetitive prostate measurements on the same subject. Furthermore, a study carried out on 10 healthy subjects shows that the six prostate metabolites creatine (Cr), total choline (Cho), Cit, Spm, mI, and scyllo‐inositol (sI) can be reliably detected in vivo, some of which—especially total Cho and Cit—have proven to be useful markers for the detection of prostate cancer. Magn Reson Med 59:966–972, 2008. © 2008 Wiley‐Liss, Inc.
Cardiac metabolism measured noninvasively by hyperpolarized 13C MRI
Authors: Golman Klaes , Petersson J. Stefan , Magnusson Peter , Johansson Edvin , Åkeson Per , Chai Chun‐Ming , Hansson Georg , Månsson Sven
Published: April 2008

Pyruvate is included in the energy production of the heart muscle and is metabolized into lactate, alanine, and CO2 in equilibrium with HCO. The aim of this study was to evaluate the feasibility of using 13C hyperpolarization enhanced MRI to monitor pyruvate metabolism in the heart during an ischemic episode. The left circumflex artery of pigs (4 months, male, 29–34 kg) was occluded for 15 or 45 min followed by 2 hr of reperfusion. Pigs were examined by 13C chemical shift imaging following intravenous injection of 1‐13C pyruvate. 13C chemical shift MR imaging was used in order to visualize the local concentrations of the metabolites. After a 15‐min occlusion (no infarct) the bicarbonate signal level in the affected area was reduced (25–44%) compared with the normal myocardium. Alanine signal level was normal. After a 45‐min occlusion (infarction) the bicarbonate signal was almost absent (0.2–11%) and the alanine signal was reduced (27–51%). Due to image‐folding artifacts the data obtained for lactate were inconclusive. These studies demonstrate that cardiac metabolic imaging with hyperpolarized 1‐13C‐pyruvate is feasible. The changes in concentrations of the metabolites within a minute after injection can be detected and metabolic maps constructed. Magn Reson Med 59:1005–1013, 2008. © 2008 Wiley‐Liss, Inc.
MRI visualization of rodent liver structure and peritoneal adhesion with dialyzate enhancement
Authors: Cheung Jerry S. , Guo Hong , Leung Joseph C.K. , Man Kwan , Lai Kar N. , Wu Ed X.
Published: April 2008

This study investigated the use of peritoneal dialysis fluid (dialyzate) as a MR contrast agent to visualize the liver structure and peritoneal adhesion in rats at 7 T. Intraperitoneal injection of dialyzate (∼0.1 ml/g) yielded excellent and consistent intraperitoneal enhancement that delineated the liver lobular structure in all rats studied (N = 8). It also allowed the MR detection of peritoneal adhesions that were surgically induced. MR measurements of adhesion surface areas correlated well with the postmortem estimations (R = 0.99; N = 6). Dialyzate persisted in the intraperitoneal cavity for up to 2 days. T1 and T2 values of undiluted dialyzate were found to be 3017.5 ± 35.3 ms and 108.4 ± 2.0 ms, respectively. These findings demonstrated dialyzate‐enhanced MRI as a potentially valuable technique to localize certain activities within liver (such as local tumor metastasis), and to monitor therapeutic interventions (e.g., against peritoneal adhesion) in preclinical research using small animal models. Magn Reson Med 59:1170–1174, 2008. © 2008 Wiley‐Liss, Inc.
High‐contrast 3D neonatal brain imaging with combined T1‐ and T2‐weighted MP‐RAGE
Authors: Conklin John , Winter Jeff D. , Thompson R. Terry , Gelman Neil
Published: April 2008

Optimization of magnetization‐prepared rapid gradient‐echo (MP‐RAGE) sequence variations for maximum white matter (WM) versus gray matter (GM) contrast in neonates at 3T was investigated. Numerical simulations were applied to optimize and compare three contrast preparation modules and to assess the effect of phase encoding (PE) order on contrast between WM and thin cortical GM layers. Simulations predict that a new sequence, which combines both T1‐ and T2‐weighting into the contrast preparation and utilizes an interleaved elliptical‐spiral PE order, should provide the strongest contrast between neonatal WM and cortical GM. This sequence was compared to a conventional MP‐RAGE acquisition (i.e., T1‐weighted preparation, centric PE order) for in vivo imaging of seven preterm newborn infants. Regional measurements of the contrast‐to‐noise ratio (CNR) between WM and GM demonstrated an increase of 50–70% (depending on GM region) using the new sequence, in good agreement with theoretical predictions. This improved contrast resulted in superior WM versus GM discrimination in intensity‐based brain tissue segmentations. Magn Reson Med 59:1190–1196, 2008. © 2008 Wiley‐Liss, Inc.
Magnetization transfer ratio as a predictor of malignancy in breast lesions: Preliminary results
Authors: Bonini Ruth Helena Morais , Zeotti Denise , Saraiva Luciano Albuquerque Lima , Trad Clovis Simao , Filho Joaquim Moraes Sarmento , Carrara Helio Humberto Angotti , de Andrade Jurandyr Moreira , Santos Antonio Carlos , Muglia Valdair Francisco
Published: April 2008

MRI is an important tool for investigating breast cancer. Although recognized as the method of choice for screening high‐risk patients, and for other indications the role of MRI for lesion characterization remains controversial. Recently some authors have advocated the use of morphologic and postcontrast features for this purpose. Quantitative breast MRI techniques have not been applied extensively in breast diseases. Magnetization transfer (MT) is a quantitative MR technique commonly used to investigate neurological diseases. In breast diseases the use of MT has been limited to improving visualization of areas of enhancement in postcontrast images. The purpose of this study was to evaluate the feasibility and utility of MT in discriminating benign from malignant breast lesions. Fifty‐two lesions, BIRADS 4 and 5, from 49 patients, were prospectively evaluated using the MT ratio (MTR). Patients were divided into two groups: benign and malignant lesions. The MTR of fat, pectoralis major muscle, fibroglandular tissue, and breast lesions were calculated. A statistically significant difference was found between MTR from benign and malignant lesions (P < 0.001). Preliminary results suggest that MT can be used to evaluate breast lesions. Further studies are necessary to better define the utility and applicability of this technique. Magn Reson Med 59:1030–1034, 2008. © 2008 Wiley‐Liss, Inc.
High b‐value q‐space diffusion‐weighted MRI of the human cervical spinal cord in vivo: Feasibility and application to multiple sclerosis
Authors: Farrell Jonathan A.D. , Smith Seth A. , Gordon‐Lipkin Eliza M. , Reich Daniel S. , Calabresi Peter A. , van Zijl Peter C.M.
Published: April 2008

Q‐space analysis is an alternative analysis technique for diffusion‐weighted imaging (DWI) data in which the probability density function (PDF) for molecular diffusion is estimated without the need to assume a Gaussian shape. Although used in the human brain, q‐space DWI has not yet been applied to study the human spinal cord in vivo. Here we demonstrate the feasibility of performing q‐space imaging in the cervical spinal cord of eight healthy volunteers and four patients with multiple sclerosis. The PDF was computed and water displacement and zero‐displacement probability maps were calculated from the width and height of the PDF, respectively. In the dorsal column white matter, q‐space contrasts showed a significant (P < 0.01) increase in the width and a decrease in the height of the PDF in lesions, the result of increased diffusion. These q‐space contrasts, which are sensitive to the slow diffusion component, exhibited improved detection of abnormal diffusion compared to perpendicular apparent diffusion constant measurements. The conspicuity of lesions compared favorably with magnetization transfer (MT)‐weighted images and quantitative CSF‐normalized MT measurements. Thus, q‐space DWI can be used to study water diffusion in the human spinal cord in vivo and is well suited to assess white matter damage. Magn Reson Med 59:1079–1089, 2008. © 2008 Wiley‐Liss, Inc.
Relaxation‐compensated fast multislice amide proton transfer (APT) imaging of acute ischemic stroke
Authors: Sun Phillip Zhe , Murata Yoshihiro , Lu Jie , Wang Xiaoying , Lo Eng H. , Sorensen A. Gregory
Published: April 2008

Amide proton transfer (APT) imaging is a variant form of chemical exchange saturation transfer (CEST) imaging that is based on the magnetization exchange between bulk water and labile endogenous amide protons. Given that chemical exchange is pH‐dependent, APT imaging has been shown capable of imaging ischemic tissue acidosis, and as such, may serve as a surrogate metabolic imaging marker complementary to perfusion and diffusion MRI. In order for APT imaging to properly diagnose heterogeneous pathologies such as stroke and cancer, fast volumetric APT imaging has to be developed. In this study the evolution of CEST contrast after RF irradiation was solved showing that although the CEST steady state is reached by the apparent longitudinal relaxation rate, the decreases of CEST contrast after irradiation is governed by the intrinsic relaxation constant. A volumetric APT imaging sequence is proposed that acquires multislice images immediately after a single long continuous wave (CW) RF irradiation, wherein the relaxation‐induced loss of CEST contrast is compensated for during postprocessing. The proposed technique was verified by numerical simulation, a tissue‐like dual‐pH phantom, and demonstrated on an embolic stroke animal model. In summary, our study has established a fast volumetric pH‐weighted APT imaging technique, allowing further investigation to fully evaluate its diagnostic power. Magn Reson Med 59:1175–1182, 2008. © 2008 Wiley‐Liss, Inc.
Reconstruction of undersampled non‐Cartesian data sets using pseudo‐Cartesian GRAPPA in conjunction with GROG
Authors: Seiberlich Nicole , Breuer Felix , Heidemann Robin , Blaimer Martin , Griswold Mark , Jakob Peter
Published: April 2008

Most k‐space‐based parallel imaging reconstruction techniques, such as Generalized Autocalibrating Partially Parallel Acquisitions (GRAPPA), necessitate the acquisition of regularly sampled Cartesian k‐space data to reconstruct a nonaliased image efficiently. However, non‐Cartesian sampling schemes offer some inherent advantages to the user due to their better coverage of the center of k‐space and faster acquisition times. On the other hand, these sampling schemes have the disadvantage that the points acquired generally do not lie on a grid and have complex k‐space sampling patterns. Thus, the extension of Cartesian GRAPPA to non‐Cartesian sequences is nontrivial. This study introduces a simple, novel method for performing Cartesian GRAPPA reconstructions on undersampled non‐Cartesian k‐space data gridded using GROG (GRAPPA Operator Gridding) to arrive at a nonaliased image. Because the undersampled non‐Cartesian data cannot be reconstructed using a single GRAPPA kernel, several Cartesian patterns are selected for the reconstruction. This flexibility in terms of both the appearance and number of patterns allows this pseudo‐Cartesian GRAPPA to be used with undersampled data sets acquired with any non‐Cartesian trajectory. The successful implementation of the reconstruction algorithm using several different trajectories, including radial, rosette, spiral, one‐dimensional non‐Cartesian, and zig–zag trajectories, is demonstrated. Magn Reson Med 59:1127–1137, 2008. © 2008 Wiley‐Liss, Inc.
The role of hematopoietic stem cell transplantation with relapsed or primary refractory childhood B‐cell non‐Hodgkin lymphoma and mature B‐cell leukemia: A retrospective analysis of enrolled cases in Japan
Authors: Fujita Naoto , Mori Tetsuya , Mitsui Tetsuo , Inada Hiroko , Horibe Keizo , Tsurusawa Masahito
Published: April 2008

Background

There have been excellent treatment results for children with B‐cell non‐Hodgkin lymphoma (B‐NHL) and mature B‐cell leukemia (B‐ALL) in the last few decades. However, a small subset of relapsed or refractory patients, after first‐line therapy, still have a poor prognosis.

Procedure

Thirty‐three patients with relapsed or primary refractory B‐NHL/B‐ALL among 327 newly diagnosed patients between 1996 and 2004 were analyzed retrospectively.

Results

After salvage therapy, 18 patients were chemotherapy‐sensitive and 15 patients suffered from progression. Among 18 patients who had a chemotherapy‐sensitive disease, 4 of 5 patients who underwent hematopoietic stem cell transplantation (HSCT) during remission survived without progression, while 3 of 12 patients who did not receive HSCT were alive without disease progression. Fifteen patients never sensitive to salvage therapy died.

Conclusions

Patients with relapsed/primary refractory B‐NHL/B‐ALL have a poor prognosis with current treatment approaches, while the patients sensitive to salvage therapy have a respectable chance to achieve a sustained complete second remission with HSCT. Pediatr Blood Cancer 2008;51:188–192. © 2008 Wiley‐Liss, Inc.
Effects of wood flour and chitosan on mechanical, chemical, and thermal properties of polylactide
Authors: Shah Bhavesh L. , Selke Susan E. , Walters Michael B. , Heiden Patricia A.
Published: April 2008

Composites of polylactide (PLA, 100–60 wt%) and wood flour (0–40 wt%) were prepared to assess the effects of wood filler content on the mechanical, chemical, thermal, and morphological properties of the composites. The polysaccharide chitosan (0–10 wt%) was added as a potential coupling agent for the PLA‐wood flour composites. Addition of wood flour significantly increased the flexural modulus and the storage modulus of PLA‐wood flour composite, but neither the wood flour nor chitosan had an effect on the glass transition temperature (Tg). Fourier transform infrared spectra did not show any evidence of covalent bonding, but chitosan at the interface between wood and PLA is thought to have formed hydrogen bonds to PLA‐carbonyl groups. SEM images of fracture surfaces showed that fiber breakage was far more common than fiber pullout in the composites. No evidence of discrete chitosan domains was seen in SEM micrographs. When added at up to 10 wt% (based on wood flour mass), chitosan showed no significant effect on the mechanical, chemical, or thermal properties of the composites, with property changes depending on wood flour content only. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers.
A novel method of hyperbranched poly(amide‐ester) modifying nano‐SiO2 and study of mechanical properties of PVC/nano‐SiO2 composites
Authors: Zhao Hui , Sun Ruimin , Luo Yunjun , Li Jie
Published: April 2008

A new method of surface chemical modification of nano‐SiO2 was proposed in the paper. In the presence of catalyst, the active hydroxyl groups on the surface of nano‐SiO2 reacted with AB2‐type monomer (N,N‐dihydroxyethyl‐3‐amino methyl propionate) by one‐step polycondensation. And the product's Fourier transform infrared graphs and transmission electron microscopy (TEM) images proved that hyperbranched poly(amine‐ester) (HPAE) was grafted from nano‐SiO2 surface successfully. Moreover, polyvinyl chloride (PVC)/modified nano‐SiO2 composites were made by melt‐blending. The composites' structures and mechanical properties were characterized by TEM, scanning electron microscopy, and electronic universal testing machine. The results showed that nano‐SiO2 grafted by HPAE increased obviously in dispersion in PVC matrix, and mechanical properties of PVC were effectively improved. Additionally, it was found that mechanical properties of PVC/nano‐SiO2 composites reached the best when weight percent of nano‐SiO2 in PVC matrix was 1%. Compared with crude PVC, the tensile strength of HPAE grafted nano‐SiO2/PVC composite increased by 24.68% and its break elongation, flexural strength, and impact strength increased by 15.73, 4.07, and 184.84%, respectively. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers