bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Microwave Digestion for Mercury Determination in Marine Biological Samples by Cold Vapour Atomic Absorption Spectrometry
Authors: Cardellicchio Nicola , di Leo Antonella , Giandomenico Santina , Santoro Stefania
Published: June 2006

Optimization of acid digestion method for mercury determination in marine biological samples (dolphin liver, fish and mussel tissues) using a closed vessel microwave sample preparation is presented. Five digestion procedures with different acid mixtures were investigated: the best results were obtained when the microwave‐assisted digestion was based on sample dissolution with HNO3‐H2SO4‐K2Cr2O7 mixture. A comparison between microwave digestion and conventional reflux digestion shows there are considerable losses of mercury in the open digestion system. The microwave digestion method has been tested satisfactorily using two certified reference materials. Analytical results show a good agreement with certified values. The microwave digestion proved to be a reliable and rapid method for decomposition of biological samples in mercury determination.
Measuring Bioavailable Trace Metals from Freshwater Sediments by Diffusive Gradients in Thin Films (DGT) in Monitoring Procedures for Quality Assessment
Authors: Camusso Marina , Gasparella Alessandro
Published: June 2006

An experimental design using passive samplers was set up in our laboratories with the aim of preparing a procedure for the assessment of trace metals bioavailability in freshwater sediments. Trace metal (Cd, Cu, Pb, Ni, and Zn) bioavailability in sediment samples were measured by diffusive gradients in thin films (DGT) devices and compared to those simultaneously extracted (SEM) in 1N HCl with acid‐volatile sulfide (AVS). During experiments DGT devices were exposed at various times (from 4 to 336h) in sediments with different physical and chemical properties and metal content, after equilibration with ambient water (1:2) for 24 h. Trace metal were progressively accumulated in DGT units and after at least 24‐48 h metal fluxes became constant. No relation was found between metal available fractions measured by DGTs and total concentrations in sediments or pore waters. On the contrary good relations were found between available metals measured by DGT and metals simultaneously extracted (SEM) in HCl 1N with acid volatile sulfide (AVS).
Investigation on a Roman Copper Alloy Artefact from Pompeii (Italy)
Authors: Baraldi Pietro , Baraldi Cecilia , Ferrari Giorgia , Foca Giorgia , Marchetti Andrea , Tassi Lorenzo
Published: June 2006

A selection of samples, obtained from a particular copper‐alloy domestic artefact of Roman style from Pompeii, has been analysed by using different techniques (IR, Raman, SEM‐EDX, FAAS), in order to investigate the chemical nature and composition of the metals utilised for such manufacturing pieces.

The surface analysis of the bright red metallic microfragments conducted by different analytical techniques, emphasises the presence of pure unalloyed copper and confirms the absence of other metallic species on the upper layers. On the contrary, the mapping analysis of the section of the laminar metal of the investigated sample shows a consistent enrichment in tin content. Finally, destructive analysis by FAAS confirms that the artefact looks like a bronze metal alloy, with a medium Sn content of about 6.5%.
Electrocatalysis of Oxygen at Hemoglobin‐Au Colloid‐1,4‐Benzenedimethanethiol Modified Electrode
Authors: Wang Guang‐feng , Deng Xiang‐hui , Zhang Wen‐zhi , Fang Bin
Published: June 2006

A novel renewable O2 sensor based on the direct electron transfer of hemoglobin (Hb) is proposed. Hb was immobilized on a gold nanoparticles (GNP) associated with a 1,4‐benzenedimethanethiol (BDT) monolayer which were modified the electrode. The direct electrochemistry of Hb was investigated by electrochemical methods and cyclic voltammetric showing a pair of redox peaks of Hb. The high efficiency of the Hb/GNP/BDT modified gold electrode towards the catalytic electro‐reduction of oxygen has been observed and the potential application of Hb/GNP/BDT modified gold electrode as biosensors to monitor O2 is proposed. The electrocatalytic response showed a linear dependence on the O2 concentration ranging from 2.0 to 40.0 μmol/L.
Methods to calculate sedimentation rates of floodplain soils in the middle region of the Elbe River
Authors: Krüger Frank , Schwartz René , Kunert Maritta , Friese Kurt
Published: June 2006

This study presents different methods to quantify the historic and recent sedimentation of floodplain soils along the Elbe River. These methods include the comparison of surface elevations, the quantification of sedimentation with the aid of anthropogenic and geogenic tracers, sediment trap studies, and the calculation of load balances. Selected results from sites at the lower section of the middle Elbe River are presented and verified. The results show that several methods are suitable. In future work it should be possible, depending on the available soil and sediment data, to calculate sedimentation in Elbe River floodplain and the loss of retention volume for larger areas.
Physical and mechanical properties of flexible polybenzoxazine resins: Effect of aliphatic diamine chain length
Authors: Allen Douglas J. , Ishida Hatsuo
Published: June 2006

A series of linear aliphatic diamine‐based benzoxazine monomers has been polymerized into transparent, crosslinked specimens that are free of voids and have good mechanical integrity. The density of these polybenzoxazines is measured as a function of the amine chain length. Dynamic mechanical analysis of these linear aliphatic polybenzoxazines shows two, chain length dependent transitions. Properties, such as room temperature modulus, glass transition temperature, crosslink density, thermal degradation temperature, and char yield, of the polybenzoxazines are investigated as a function of the chain length. All these properties exhibit strong dependence on the chain length. These aliphatic amine‐based polybenzoxazines are found to be much more flexible than the bisphenol‐type polybenzoxazines. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2798–2809, 2006
Fabrication and characterization of a persimmon leaves (PL)/poly(acrylonitrile) (PAN) blend bio‐fiber
Authors: Li De‐Lan , Shen Qing , Ding Hong‐Gui , Gu Qing‐Feng , Wang Zhi‐Xin
Published: June 2006

Adopting persimmon leaves, PL, as a biomaterial to blend with poly(acrylonitrile) (PAN) via the wet spinning method, a PL/PAN blend biofiber was fabricated. On the basis of mechanical measurements, X‐ray diffraction, and DSC characterization, it was found that this biofiber has acceptable mechanical properties for further applying to different cases. Results also showed that though the crystal structure, especially the crystal size, is changed indeed for blend fiber, it seems to be of less influence on the thermal properties, especially the crystallization temperature, Tc. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2810–2813, 2006
Poly(aspartic‐acid) derivatives as polymeric micelle drug delivery systems
Authors: Jiang Tong‐ying , Wang Zhong‐yan , Chen Chuang , Mo Feng‐kui , Xu Yan‐li , Tang Lin‐xi , Liang Ji‐jun
Published: June 2006

A novel amphiphilic biodegradable graft copolymer based on poly(aspartic acid) (PASP) was prepared by coupling monomethoxy poly(ethylene glycol) as the hydrophilic segment with PASP‐g‐octadecyl (PASP‐g‐OD) as the hydrophobic backbone. The critical micelle concentration of the copolymer was obtained by measuring the conductivity and fluorescence spectroscopy. Polymeric micelles were prepared with the solvent evaporation method, and the size distribution and morphology of the polymeric micelles were characterized by dynamic light scattering and transmission electron microscopy. The ability of the PASP derivatives to solubilize hydrophobic drugs was investigated using methotrexate (MTX), oleanolic acid, and podophyllotoxin (PODO) as models. The results demonstrated that drug solubility depends on the copolymer concentration, copolymer composition, as well as the physicochemical property of the drug. A stability study performed with PODO loaded by polymeric micelle solution demonstrated that the micelle carrier could protect the drug from being destroyed in a pH 7.4 buffer solution; however, the micelle did not protect it in a pH 9.5 buffer solution. Pharmacokinetic studies were carried out by intravenous administration of MTX loaded by polymeric micelle solution and MTX solution. The results demonstrated that the polymeric micelle prolonged the drug permanence in blood circulation with a mean residence time of about 2.37 times and increased the systemic bioavailability with the area under the drug concentration–time curve by about 2.34 times. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2871–2878, 2006
Novel organosoluble poly(amide‐imide‐imide)s synthesized from new tetraimide‐dicarboxylic acid by condensation with 4,4′‐oxydiphthalic anhydride, 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene, trimellitic anhydride, and various aromatic diamines
Authors: Yang Chin‐Ping , Chen Ya‐Ping , Woo E. M.
Published: June 2006

A new monomer of tetraimide‐dicarboxylic acid (IV) was synthesized by starting from ring‐opening addition of 4,4′‐oxydiphthalic anhydride, trimellitic anhydride, and 1,4‐bis(4‐amino‐2‐trifluoromethylphenoxy)benzene at a 1:2:2 molar ratio in N‐methyl‐2‐pyrrolidone (NMP). From this new monomer, a series of novel organosoluble poly(amide‐imide‐imide)s with inherent viscosities of 0.7–0.96 dL/g were prepared by triphenyl phosphite activated polycondensation from the tetraimide‐diacid with various aromatic diamines. All synthesized polymers were readily soluble in a variety of organic solvents such as NMP and N,N‐dimethylacetamide, and most of them were soluble even in less polar m‐cresol and pyridine. These polymers afforded tough, transparent, and flexible films with tensile strengths ranging from 99 to 125 MPa, elongations at break from 12 to 19%, and initial moduli from 1.6 to 2.4 GPa. The thermal properties and stability were also good with glass‐transition temperatures of 236–276°C and thermogravimetric analysis 10 wt % loss temperatures of 504–559°C in nitrogen and 499–544°C in air. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2854–2864, 2006
Transetherification of melamine–formaldehyde resin methyl ethers and competing reaction of self‐condensation
Authors: Pavlyuchenko V. N. , Ivanchev S. S. , Rätzsch M. , Bucka H. , Primachenko O. N. , Leitner P. , Khaikin S. Ya.
Published: June 2006

Transetherification of methyl ethers of melamine‐formaldehide resins (MER) with monophenyl ethers of ethylene glycol or propylene glycol (ROH) and competing reaction of self‐condensation are studied depending on MER composition (amounts of CH3O, CH2OH, and NH2 groups), ROH type, MER/ROH molar ratio, presence or absence of acid catalysts, and temperature. High rates of self‐condensation processes prevent a complete conversion of CH3O into RO‐groups. It turned out MER free of methylol groups were not able to be transetherified with high yields due to a premature gelation taking place prior to attaining 50% conversion of methoxy groups (∼4 mol/kg) even at low MER/ROH ratios. In contrast, transetherification of MER with methylol groups content up to 3 mol/kg affords the incorporation of RO‐groups into the resin up to 8 mol/kg owing to direct etherification of CH2OH groups. The following factors are responsible for the growth of etherified product yield: presence of methylol groups in MER in some amounts without deterioration of MER–ROH compatibilization; CH3O/ROH molar ratio no higher than 1; primary alcohols (ROH) is more preferable compared to secondary ones; thermal activation of the process is more efficient in comparison with acidic catalysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2977–2985, 2006
Mechanical and thermal properties of ABS and leather waste composites
Authors: Ramaraj B.
Published: June 2006

To determine the possibility of using leather waste as reinforcing filler in the thermoplastic polymer composite, acrylonitrile–butadiene–styrene (ABS) as the matrix and leather buffing powder as reinforcing filler were used to prepare a particulate reinforced composite to determine testing data for the physical, mechanical, and thermal properties of the composites, according to the filler loading in respect to thermoplastic polymer. The ABS and leather powder composites were prepared by the extrusion of ABS with 2.5, 5, 7.5, 10, 12.5, and 15 wt % of leather powder in corotating twin screw extruder. The extruded strands were cut into pellets and injection molded to make specimens. These specimens were tested for physicomechanical properties like tensile and flexural strengths, tensile and flexural modulus, Izod and charpy impact strength, abrasion resistance, Rockwell hardness, density, Heat deflection temperature (HDT) and Vicat softening point (VSP), water absorption, and thermal degradation analysis. The incorporation of leather waste powder does not affect the tensile, flexural strengths, Izod impact strength, abrasion resistance, Rockwell hardness, density, HDT and VSP values drastically. However, the tensile modulus, tensile elongation, and charpy impact strength values are reduced significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3062–3066, 2006
Formation of Freestanding Single‐Walled Carbon Nanotubes by Plasma‐Enhanced CVD
Authors: Kato T. , Hatakeyama R.
Published: June 2006

Freestanding individual single‐walled carbon nanotubes (SWNTs) are successfully produced using plasma‐enhanced (PE)CVD. The quantitative effects of plasmas on SWNT growth are also discussed on the basis of detailed plasma measurements and simple calculations. According to these quantitative results, it is found that the plasma sheath effectively plays the role of driving force in making individual SWNTs stand vertically on a substrate surface. This three‐dimensional alignment control of individual SWNTs based on plasma science and technology has huge potential to create a new type of architecture for future nanotube devices.
Developmental cell death during Xenopus metamorphosis involves BID cleavage and caspase 2 and 8 activation
Authors: Du Pasquier D. , Rincheval V. , Sinzelle L. , Chesneau A. , Ballagny C. , Sachs L.M. , Demeneix B. , Mazabraud A.
Published: June 2006

Elimination of tadpole organs during Xenopus metamorphosis is largely achieved through apoptosis, and recent evidence suggest involvement of the mitochondrial death route and bax‐initiated caspase‐3 and ‐9 deployment. However, events upstream of the activation of Bax are unknown. In other models, proteins of the BH3‐only group such as BID are known to assure this function. We show that Xenopus bid transcript levels increase at metamorphosis in larval cells destined to disappear. This increase correlates with an abrupt rise in Caspase‐2 and ‐8 mRNA levels and an enhanced activity of Caspase‐2 and ‐8. In BIDGFP transgenic animal's tail regression is accelerated. The cleavage of BIDGFP fusion protein during natural or T3‐induced metamorphosis was specifically inhibited by caspase‐8 inhibitors. Our results show that tail regression at metamorphosis implicates an apoptotic pathway inducible by T3 hormone in an organ autonomous manner and involving the cell death executioners BID and Caspases‐2 and ‐8. Developmental Dynamics 235:2083–2094, 2006. © 2006 Wiley‐Liss, Inc.
Chiral separation of cetirizine by capillary electrophoresis
Authors: Van Eeckhaut Ann , Michotte Yvette
Published: June 2006

Chiral separation of cetirizine, a second‐generation H1‐antagonist, was studied by CD‐mediated CE. Several parameters, including pH, CD type, buffer concentration, type of co‐ion, applied voltage and temperature, were investigated. The best conditions for chiral separation were obtained using a 75 mM triethanolamine‐phosphate buffer (pH 2.5) containing 0.4 mg/mL heptakis(2,3‐diacetyl‐6‐sulfato)‐β‐CD and 10% ACN. Online UV detection was performed at 214 nm, a voltage of 20 kV was applied and the capillary was temperature controlled at 25°C by liquid cooling. Hydrodynamic injection was performed for 1 s. The method was validated for the quantification of levocetirizine in tablets and for enantiomeric purity testing of the drug substance. Selectivity, linearity, LOD and LOQ, precision and accuracy were evaluated for both methods. The amount of levocetirizine dihydrochloride in the commercially available tablets was quantified and was found to be within the specification limits of the claimed amount (5 mg). The amount of distomer in levocetirizine drug substance was found to be 0.87 ± 0.09% w/w, which is in agreement with the certificate of analysis supplied by the company.
Simulation of flows with violent free surface motion and moving objects using unstructured grids
Authors: Löhner Rainald , Yang Chi , Oñate Eugenio
Published: June 2006

A volume of fluid (VOF) technique has been developed and coupled with an incompressible Euler/Navier–Stokes solver operating on adaptive, unstructured grids to simulate the interactions of extreme waves and three‐dimensional structures. The present implementation follows the classic VOF implementation for the liquid–gas system, considering only the liquid phase. Extrapolation algorithms are used to obtain velocities and pressure in the gas region near the free surface. The VOF technique is validated against the classic dam‐break problem, as well as series of 2D sloshing experiments and results from SPH calculations. These and a series of other examples demonstrate that the ability of the present approach to simulate violent free surface flows with strong nonlinear behaviour. Copyright © 2006 John Wiley & Sons, Ltd.
Arsenic derivatives in hematologic malignancies: a role beyond acute promyelocytic leukemia?
Authors: Verstovsek Srdan , Giles Francis , Quintás‐Cardama Alfonso , Perez Nichole , Ravandi‐Kashani Farhad , Beran Miloslav , Freireich Emil , Kantarjian Hagop
Published: June 2006

The importance of arsenic trioxide (As2O3) has been underscored over the last decade due to its efficacy against acute promyelocytic leukemia (APL), a disease in which this agent has been associated with complete hematologic and molecular remission rates of 87% and 83%, respectively. The different molecular mechanisms of action of As2O3 suggest its applicability in hematologic malignancies other than APL. However, responses obtained thus far have consisted of improvements in signs and symptoms without the elimination of a given disease. Toxicities derived from As2O3 are significant but manageable and reversible. However, the risk/benefit ratio of As2O3 in hematologic malignancies other than APL is still unclear. The development of new generations of orally bioavailable inorganic, as well as new organic, arsenic compounds with improved toxicity profiles may bolster the therapeutic application of arsenic derivatives in hematologic malignancies such as leukemia, multiple myeloma and myelodysplastic syndromes. Copyright © 2006 John Wiley & Sons, Ltd.
Can the semiempirical PM3 scheme describe iron‐containing bioinorganic molecules?
Authors: McNamara Jonathan P. , Sundararajan Mahesh , Hillier Ian H. , Ge Jun , Campbell Andrew , Morgado Claudio
Published: June 2006

A set of iron parameters for use in the semiempirical PM3 method have been developed to allow the structure and redox properties of the active sites of iron‐containing proteins to be accurately modeled, focussing on iron–sulfur, iron–heme, and iron‐only hydrogenases. Data computed at the B3LYP/6‐31G* level for a training set of 60 representative complexes have been employed. A gradient‐based optimization algorithm has been used, and important modifications of the core repulsion function have been highlighted. The derived parameters lead in general to good predictions of the structure and energetics of molecules both within and outside the training set, and overcome the extensive deficiencies of a B3LYP/STO‐3G model. Particularly encouraging is the success of the parameters in describing [4Fe‐4S] cubanes. The derived parameter set provides a starting point should greater accuracy for a more restricted range of compounds be required. © 2006 Wiley Periodicals, Inc. J Comput Chem 27: 1307–1323, 2006
MRI, volumetry, 1H spectroscopy, and cerebropetal blood flowmetry in childhood idiopathic anatomic megalencephaly
Authors: Koudijs Suzanne M. , van der Grond Jeroen , Hoogendoorn Mechteld L.C. , Hulshoff Pol Hilleke E. , Schnack Hugo G. , Witkamp Theo D. , Gooskens Rob H.J.M. , van Nieuwenhuizen Onno , Braun Kees P.J.
Published: June 2006

Purpose

To evaluate cerebral abnormalities in childhood idiopathic anatomic megalencephaly (MC) by means of different magnetic resonance (MR) modalities.

Materials and Methods

MRI, volumetry, spectroscopy, and cerebropetal blood flowmetry were performed in six children with idiopathic anatomic MC, and seven volunteers.

Results

MRI revealed an increased ventricular system in five of six patients. A thalamic hamartoma was found in one patient and a Chiari I malformation was found in two. Volumetric analysis showed a disproportional increase of ventricular volume but normal subarachnoid cerebrospinal fluid (CSF) volume. Supratentorial volume was disproportionally increased compared to cerebellar volume. Intracranial volume correlated significantly with skull circumference. MR spectroscopy (MRS) N‐acetyl aspartate/choline (NAA/Cho) peak ratios in WM were significantly higher in patients than in controls. Choline/creatine (Cho/Cr) peak ratios in WM were significantly lower in patients. Cortical gray matter (GM) MRS ratios were unaltered. Cerebropetal flow was increased in MC, possibly related to increased brain volume.

Conclusion

This study reveals associated developmental anomalies for idiopathic anatomic MC. A relative ventriculomegaly was found, which should not be misinterpreted as true hydrocephalus. In contrast to metabolic MC, MRS showed no severe disturbances. Total intracranial volume is correlated to skull circumference and cerebropetal blood flow. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
High‐resolution, time‐resolved MRA provides superior definition of lower‐extremity arterial segments compared to 2D time‐of‐flight imaging
Authors: Thornton F.J. , Du J. , Suleiman S.A. , Dieter R. , Tefera G. , Pillai K.R. , Korosec F.R. , Mistretta C.A. , Grist T.M.
Published: June 2006

Purpose

To evaluate a novel time‐resolved contrast‐enhanced (CE) projection reconstruction (PR) magnetic resonance angiography (MRA) method for identifying potential bypass graft target vessels in patients with Class II–IV peripheral vascular disease.

Materials and methods

Twenty patients (M:F = 15:5, mean age = 58 years, range = 48–83 years), were recruited from routine MRA referrals. All imaging was performed on a 1.5 T MRI system with fast gradients (Signa LX; GE Healthcare, Waukesha, WI). Images were acquired with a novel technique that combined undersampled PR with a time‐resolved acquisition to yield an MRA method with high temporal and spatial resolution. The method is called PR hyper time‐resolved imaging of contrast kinetics (PR‐hyperTRICKS). Quantitative and qualitative analyses were used to compare two‐dimensional (2D) time‐of‐flight (TOF) and PR‐hyperTRICKS in 13 arterial segments per lower extremity. Statistical analysis was performed with the Wilcoxon signed‐rank test.

Results

Fifteen percent (77/517) of the vessels were scored as missing or nondiagnostic with 2D TOF, but were scored as diagnostic with PR‐hyperTRICKS. Image quality was superior with PR‐hyperTRICKS vs. 2D TOF (on a four‐point scale, mean rank = 3.3 ± 1.2 vs. 2.9 ± 1.2, P < 0.0001). PR‐hyperTRICKS produced images with high contrast‐to‐noise ratios (CNR) and high spatial and temporal resolution. 2D TOF images were of inferior quality due to moderate spatial resolution, inferior CNR, greater flow‐related artifacts, and absence of temporal resolution.

Conclusion

PR‐hyperTRICKS provides superior preoperative assessment of lower limb ischemia compared to 2D TOF. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Delivery and assessment of endovascular stents to repair aortic coarctation using MR and X‐ray imaging
Authors: Saeed Maythem , Henk Christine B. , Weber Oliver , Martin Alastair , Wilson Mark , Shunk Kendrick , Saloner David , Higgins Charles B.
Published: June 2006

Purpose

To investigate the utility of MR and X‐ray imaging for characterizing aortic coarctation and flow, and guiding the endovascular catheter to place a stent to repair the coarctation.

Materials and Methods

The descending aorta in eight dogs was looped with elastic band and tightened distal to the subclavian artery. Balanced fast field echo (bFFE) and velocity‐encoded cine (VEC) MRI sequences were used for device tracking and measuring aortic flow. A T1‐weighted fast‐field echo sequence (T1‐FFE) was used to visualize the coarctation and roadmap the aorta. Nitinol stents were guided by a nitinol guidewire and placed under MR guidance.

Results

Aortic coarctation was visible on MR and X‐ray imaging. The procedure success rate was 88%. VEC MRI measured the changes in aortic flow (baseline = 1.3 ± 0.2, coarctation = 0.2 ± 0.02, and stent placement = 0.8 ± 0.1 liters/minute). A significant reduction in iliac blood pressure was measured after coarctation, but it was reversed by stent placement. The stent lumen was visible on X‐ray fluoroscopy, but not on MRI.

Conclusion

Stent deployment to repair aortic coarctation is feasible under MR guidance. The combined use of MR and X‐ray imaging is effective for anatomic and functional evaluation of aortic coarctation dilation, which may be crucial for optimal therapy. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Accelerated volumetric MRI with a SENSE/GRAPPA combination
Authors: Blaimer Martin , Breuer Felix A. , Seiberlich Nicole , Mueller Matthias F. , Heidemann Robin M. , Jellus Vladimir , Wiggins Graham , Wald Lawrence L. , Griswold Mark A. , Jakob Peter M.
Published: June 2006

Purpose

To combine the specific advantages of the generalized autocalibrating partially parallel acquisitions (GRAPPA) technique and sensitivity encoding (SENSE) with two‐dimensional (2D) undersampling.

Materials and Methods

By splitting the 2D reconstruction process into multiple one‐dimensional (1D) reconstructions, the normal 1D GRAPPA method can be used for image reconstruction. Due to this data‐handling process, a GRAPPA reconstruction is performed along the phase‐encoding (PE) direction and effectively a SENSE reconstruction is performed along the partition‐encoding (PAE) direction.

Results

In vivo experiments demonstrate the successful implementation of the SENSE/GRAPPA combination. Experimental results with up to 9.6‐fold acceleration using a prototype 32‐channel receiver head coil array are presented.

Conclusion

The proposed SENSE/GRAPPA combination for 3D imaging allows the GRAPPA method to be applied in combination with 2D undersampling. Because the SENSE/GRAPPA combination is not based on knowledge of spatial coil sensitivities, it should be the method of choice whenever it is difficult to extract the sensitivity information. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Intravenous contrast‐enhanced dynamic MR urography: Diagnosis of vesicoureteral reflux during bladder filling with time‐signal intensity curves
Authors: Kocaoglu Murat , Bulakbasi Nail , Ilica Ahmet Turan , Gok Faysal , Tayfun Cem , Somuncu Ibrahim
Published: June 2006

Purpose

To evaluate the time‐signal intensity (SI) curves generated from intravenous (IV) gadodiamide‐enhanced dynamic magnetic resonance (MR) urographic scans for identifying vesicoureteral reflux (VUR) during bladder filling.

Materials and Methods

MR urographic studies of children were retrospectively reviewed, and 52 ureterorenal units of 26 patients (15 females and 11 males, mean age = 5.5 years) who had also undergone voiding cystourethrographic (VCUG) examination were included in this study. The patients were examined on a 1.5T scanner. For functional MR urography and to generate time‐SI curves, we used a post IV contrast‐enhanced two‐dimensional (2D) fast field echo (FFE) sequence (TR = 17 msec, TE = 3.2 msec, flip angle (FA) = 90°) in the coronal plane. MR urographic time‐SI curves that demonstrated a prompt and concave fall of the initial third phase followed by intermittent or constantly increasing SI peaks above the baseline from which the second phase starts were considered to have VUR. We compared the differences in time‐SI curves between the control group and patients with VUR during bladder filling.

Results

Twelve ureterorenal units of eight patients (four bilateral and four unilateral) had VUR during bladder filling on VCUG. The time‐SI curves of these patients showed intermittent (N = 8 ureterorenal units), and constantly increasing (N = 4 ureterorenal units) SI peaks consistent with VUR. One patient also had bilateral abnormal time‐SI curves suggesting VUR despite the normal VCUG study. In the control group, 25 units had normal triphase time‐SI curves, six renal units had urinary dilatation with good washout after diuretic injection, and four renal units had upper urinary dilatation without contrast washout, while five renal units did not show any function. None of the patients in the control group revealed distortion in the time‐SI curve. The differences in time‐SI curves patterns between the control group and patients with VUR during bladder filling were statistically significant (P < 0.001).

Conclusion

After a prompt and concave decrease of the initial third phase of the time‐SI curve, intermittent spikes or a constant rise in SI above the baseline suggest the existence of VUR. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Quantitative diffusion imaging in breast cancer: A clinical prospective study
Authors: Rubesova Erika , Grell Anne‐Sophie , De Maertelaer Viviane , Metens Thierry , Chao Shih‐Li , Lemort Marc
Published: June 2006

Purpose

To study the correlation between apparent diffusion coefficient (ADC) and pathology in patients with undefined breast lesion, to validate how accurately ADC is related to histology, and to define a threshold value of ADC to distinguish malignant from benign lesions.

Materials and Methods

Seventy‐eight patients (110 lesions) were referred for positive or dubious findings. Three‐dimensional fast low‐angle shot (3D‐FLASH) with contrast injection was applied. EPI diffusion‐weighted imaging (DWI) with fat saturation was performed, and ROIs were selected on subtraction 3D‐FLASH images before and after contrast injection, and copied on an ADC map. Inter‐ and intraobserver analyses were performed.

Results

At pathology 22 lesions were benign, 65 were malignant, and 23 were excluded. The ADCs of malignant and benign lesions were statistically different. In malignant tumors the ADC was (mean ± SEM) 0.95 ± 0.027 × 10–3mm2/second, and in benign tumors it was 1.51 ± 0.068 × 10−3mm2/second. According to receiver operating characteristic (ROC) curves, we found a threshold between malignant and benign lesions for highest sensitivity and specificity (both 86%) around 1.13 ± 0.10 × 10−3mm2/second. For a threshold of 0.95 ± 0.10 × 10−3mm2/second, specificity was 100% but sensitivity was very low. Inter‐ and intraobserver studies showed good reproducibility.

Conclusion

The ADC may help to differentiate benign and malignant lesions with good specificity, and may increase the overall specificity of breast MRI. J. Magn. Reson. Imaging 2006. © 2006 Wiley‐Liss, Inc.
Melatonin content in grape: myth or panacea?
Authors: Iriti Marcello , Rossoni Mara , Faoro Franco
Published: June 2006

Melatonin (N‐acetyl‐5‐methoxytryptamine) was detected by a modified HPLC method and ELISA tests in extracts of eight different Vitis vinifera cultivars, namely Nebbiolo, Croatina, Sangiovese, Merlot, Marzemino, Cabernet Franc, Cabernet Sauvignon and Barbera. Its concentration varied greatly among the cultivars, being the highest in Nebbiolo (0.965 ng g−1) and Croatina (0. 870 ng g−1). Field treatments of grapevine with the plant defence activator benzothiadiazole, greatly improved the melatonin content in berry skin extracts, indicating a possible strategy to raise the content of this important pharmaconutrient in plants, while inducing resistance to pathogens. The finding of this compound in grape suggests that the well‐established pharmaconutritional properties of this fruit are due not only to the presence of polyphenolic nutraceuticals, such as resveratrol, anthocyanins and proanthocyanidins, but also to the powerful antioxidant activity of melatonin. Copyright © 2006 Society of Chemical Industry
Novel Densely Alkylated Hydroxyl‐Functional Polyvinylpyrrolidone Showing Phase‐Selective Solubility
Authors: Engström Jonas U. A. , Helgee Bertil , Sung Shayna D. , Bergbreiter David E.
Published: June 2006

Summary: Polyvinylpyrrolidone (PVP) is a commonly used polymer with many different applications in the pharmaceutical, cosmetic and food industries. However, the lack of reactive groups and the difficulty in copolymerizing the monomer, N‐vinylpyrrolidin‐2‐one (NVP) with most other monomers, limits the possibility of modifying the physical and chemical properties of the polymer. Monomers that are derivatives of NVP itself are expected to show small differences in radical reactivity as compared to the parent monomer and provide a way of adjusting the polymer properties without extensive compositional drift during copolymerization. Here we present the synthesis of two new functionalized NVP‐based monomers and their copolymerization with alkylated NVP‐monomers for the preparation of two functionalized PVPs with phase‐selective solubility in heptane. Both copolymers showed 99.99% selective solubility in heptane over DMF (thermomorphic system) and 99.99% in heptane over 90% EtOH‐H2O (latent biphasic system). These results suggest that the polymers could be used as soluble supports to facilitate recovery and recycling of catalysts or reagents from liquid/liquid systems after homogeneous reactions.

Phase‐selectively soluble polyvinylpyrrolidone copolymer.

magnified image

Phase‐selectively soluble polyvinylpyrrolidone copolymer.
Thermally Stable, Organosoluble, and Colorless Poly(ether imide)s Having Ortho‐Linked Aromatic Units in the Main Chain and Trifluoromethyl Pendent Groups
Authors: Yang Chin‐Ping , Wang Je‐Min , Su Yu‐Yang , Hsiao Sheng‐Huei
Published: June 2006

Summary: A novel series of aromatic poly(ether imide)s (PEIs) IVa–h containing ortho‐linked aromatic units and pendent trifluoromethyl (CF3) groups were prepared from 2,3‐bis(3,4‐dicarboxyphenoxy)naphthalene dianhydride (I) with various CF3‐substituted aromatic bis(ether amine)s IIa–h via a conventional two‐stage process including ring‐opening polyaddition to form the poly(amic acid)s followed by either chemical or thermal imidization to the PEIs. The inherent viscosities of PEIs IVa–h were in the range of 0.43–0.86 dL · g−1 that corresponded to weight‐average and number‐average molecular weights (by gel permeation chromatography) of 36 000–73 000 and 23 000–51 000, respectively. All the IV series were highly soluble in several organic solvents and could be solution‐cast into transparent, flexible, and strong films. These films were essentially colorless; their cut‐off wavelengths were between 368 and 377 nm and a very low b* value (a yellowness index) ranging from 4.1 to 5.5. They had useful levels of thermal stability associated with moderately high‐glass transition temperatures (208–281 °C), 10% weight‐loss temperatures in excess of 492 °C, and char yields at 800 °C in nitrogen higher than 51%. They also showed low water uptakes of 0.25–0.48% and low dielectric constants of 3.06–3.67 at 10 kHz. For a comparative study, a series of structurally similar, non‐fluorinated PEIs Va–h from dianhydride I and bis(ether amine)s II′a–h were also prepared and characterized.

A novel series of aromatic poly(ether imide)s (PEIs)IVa–h.

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A novel series of aromatic poly(ether imide)s (PEIs)IVa–h.
Non‐Shrinking Networked Materials from the Cross‐Linking Copolymerization of Spiroorthocarbonate with Bifunctional Oxetane
Authors: Nagai Daisuke , Nishida Masaki , Nagasawa Tomomi , Ochiai Bungo , Miyazaki Koji , Endo Takeshi
Published: June 2006

Summary: The cationic ring‐opening copolymerization behavior of SOC1 with BOXT and the properties of the obtained cross‐linked copolymers are described. SOC1 and BOXT are cationically copolymerized under various feed ratios to obtain the corresponding cross‐linked copolymers in 73–96% yields. The volume change during copolymerization could be controlled by the addition of SOC1 to obtain non‐shrinking or volume‐expanding copolymers. The glass transition temperatures (Tg) of the copolymers also decrease linearly with the feed ratio of SOC1, which suggests that the introduction of the flexible poly(SOC1) segment into the rigid BOXT cross‐linked segment relieves the internal stress in the resins that severely degrade their mechanical properties.

Cationic copolymerization of SOC1 and BOXT.

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Cationic copolymerization of SOC1 and BOXT.
Computations of eigenpair subsets with the MRRR algorithm
Authors: Marques Osni A. , Parlett Beresford N. , Vömel Christof
Published: June 2006

The main advantage of inverse iteration over the QR algorithm and Divide & Conquer for the symmetric tridiagonal eigenproblem is that subsets of eigenpairs can be computed at reduced cost.

The MRRR algorithm (MRRR=multiple relatively robust representations) is a clever variant of inverse iteration without the need for reorthogonalization. STEGR, the current version of MRRR in LAPACK 3.0, does not allow for subset computations. The next release of STEGR is designed to compute a (sub‐)set of k eigenpairs with 𝒪(kn) operations.

Because of the special way in which eigenvectors are computed, MRRR subset computations are more complicated than when using inverse iteration. Unlike the latter, MRRR sometimes cannot ignore the unwanted part of the spectrum.

We describe the problems with what we call ‘false singletons’. These are eigenvalues that appear to be isolated with respect to the wanted eigenvalues but in fact belong to a tight cluster of unwanted eigenvalues. This paper analyses these complications and ways to deal with them. Published in 2006 by John Wiley & Sons, Ltd.
Physicians, pharmacists and patients' compliance with chronic treatment in Bulgaria
Authors: Petkova Valentina
Published: June 2006

Purpose

To study the patient–physician and patient–pharmacist interrelation in order to reveal the systematic factors that influence patients' compliance.

Methods

Standard individual questionnaires were developed and used to assess compliance and non‐compliance among different categories of patients suffering from chronic diseases.

Results

There is a relatively good communication between the patients and the health‐care givers but in order to improve compliance (adherence) further, this level of communication has to be improved. The main reasons for non‐adherence were: the high cost of drugs, the complexity of the daily regimen, negligence, and distrust of treatment. Insufficient information in the patient information leaflet, together with an inappropriate drug formulation also appear to be important factors that cause non‐compliance. This is especially so, when patients have to receive more than one drug, or medications in different dosage forms, and it is particularly marked when elderly people are involved.

Conclusion

Despite the comparatively high level of compliance found in this study (50–92%), there are possibilities for individualization of treatment that merit attention in order that the level of compliance can be improved. Copyright © 2006 John Wiley & Sons, Ltd.
Preparation and characterization of colloidal dispersions of vinyl alcohol–vinyl acetate copolymers: application as stabilizers for vinyl chloride suspension polymerization
Authors: Hong Satha , Albu Roxana , Labbe Clorinthe , Lasuye Thierry , Stasik Bernard , Riess Gérard
Published: June 2006

Well‐defined colloidal dispersions of vinyl alcohol–vinyl acetate copolymers (PVAs) with different degrees of hydrolysis (DH) were prepared by a coacervation technique. Colloidal particles in the size range 150–250 nm, with an acetate‐rich core and a hydrophilic PVA corona, were obtained using a combination of a hydrophobic PVA (PVA II) having an average DH ($\overline{DH}$) value of 43 mol% with a ‘blocky’ hydrophilic PVA (PVA I) with a $\overline{DH}$ value of 72 mol%. The core–shell structure of these particles was demonstrated using 1H NMR and using fluorescence‐labelled PVA I. The stabilization efficiency of PVA I and PVA II and their combination was examined for 1‐chlorobutane–water emulsions, as a ‘model solvent’ for vinyl chloride–water emulsions. Preliminary tests of vinyl chloride suspension polymerization confirmed the beneficial effect of PVA I and PVA II combinations as stabilizers on the granulometry and the porosity specifications of the poly(vinyl chloride) grains. Copyright © 2006 Society of Chemical Industry
Stereoelectronic effects in radical processes
Authors: Brandi Paolo , Galli Carlo , Gentili Patrizia
Published: June 2006

A kinetic study of the H‐abstraction reaction from cyclic and acyclic alkylarene substrates by the nitroxyl radical (dubbed BTNO) of 1‐hydroxy‐benzotriazole (HBT) has been carried out in MeCN solution at 25°C. BTNO was generated from one‐electron oxidation of HBT by cerium(IV) ammonium nitrate. The H‐abstraction reactivity measured with the cyclic alkylarenes is invariably higher than that with the acyclic counterparts. This is explained as the contribution of hyperconjugation between the aromatic π‐system and the scissile benzylic CH bond of the substrate, which weakens the CH bond in the transition state and promotes its cleavage. Stereoelectronic considerations enable to appreciate why the weakening effect is more pronounced in the cyclic system than in the acyclic counterpart, thereby justifying the higher reactivity of the former. Evidence for the intervention of stereoelectronic effects is embodied by the dissociation energies of the CH bonds, having always lower values for the cyclic substrates investigated. Copyright © 2006 John Wiley & Sons, Ltd.
Laboratory and field tests of spray‐dried and granular formulations of a Bacillus thuringiensis strain with insecticidal activity against the sugarcane borer
Authors: Rosas‐García Ninfa M
Published: June 2006

Formulations of Bacillus thuringiensis Berliner (Bt) with insecticidal activity against the sugarcane borer, Diatraea saccharalis Fabricius (Lepidoptera: Pyralidae), were developed and tested under laboratory and field conditions. The formulations were prepared using biodegradable polymers such as modified corn starch as an encapsulating agent, gelatin as an adherent, powdered sugarcane as a feeding stimulant and a Bt var. kurstaki GM‐34 strain from a non‐sugarcane region as the active ingredient. The spore–crystal complex of this strain was mixed at three different concentrations (30, 70 and 100 g kg−1) with the other ingredients. The blends were prepared as spray‐dried and granular formulations, and then submitted to laboratory tests with two day old larvae of D. saccharalis and field tests in sugarcane crops with natural sugarcane borer infestation. Spray‐dried formulations in laboratory bioassays caused mortality near 100% with all three concentrations, and granular formulations caused mortality around 84%. The field tests showed that spray‐dried formulations at 70 and 100 g kg−1 concentrations were as effective as a commercial bioinsectide (Lepinox™), while granular formulations were ineffective. Copyright © 2006 Society of Chemical Industry
Computational study of 4‐fluoro‐4‐chloro‐ and 4‐fluoro‐4‐bromo‐4‐silathiacyclohexane S‐oxides: Effect of halogen on the SO→Si intramolecular coordination in the boat and twist conformers
Authors: Shainyan Bagrat A.
Published: June 2006

Chair, twist, and boat conformations of axial and equatorial 4‐fluoro‐4‐chloro‐ and 4‐fluoro‐4‐bromo‐4‐silathiacyclohexane S‐oxides have been calculated at the second‐order Møller–Plesset (MP2) and density functional theory (DFT) levels of theory. The 2,5‐twist and 1,4‐boat conformers of the axial sulfoxides are stabilized by transannular interaction between the sulfinyl oxygen and silicon to give trigonal bipyramidal geometry at silicon. The stability of conformers containing pentacoordinate silicon is governed by the balance of the transannular sulfinyl oxygen–silicon coordination, nonbonded H…H and O…Hlgax interactions, electronegativity of Hlgax and nucleofugality of Hlgeq, and may approach the stability of the lowest‐energy chair conformers. The effect of pentacoordination on the energy and geometry of Si‐halogenated 4‐silathiane S‐oxides is analyzed as a function of the halogen nature and position. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
State generalization method with support vector machines in reinforcement learning
Authors: Goto Ryo , Matsuo Hiroshi
Published: June 2006

A discrete state space is often the subject of conventional reinforcement learning; continuous states must be discretized in order to be handled with conventional learning methods. However, simple discretization increases the state dimensionality and results in an exponential increase in the number of states. The time needed for learning and the memory requirements are therefore greatly increased. In this paper, the authors propose an algorithm for generalizing multidimensional continuous states using a support vector machine (SVM). This algorithm estimates the optimal action in an unknown state using SVM and can be expected to adapt to the environment in a smaller number of trials. To compare this method with conventional algorithms, a simulation experiment was carried out for an assumed task in which a robot is caused to move toward a goal. As a result, it was confirmed that this algorithm adapted to the environment in a smaller number of trials. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(9): 77–86, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20140
Article for “Diversity Stories in Community Research and Action” Facing Resistance in Waking Up to Privilege
Authors: Vasquez Hugh
Published: June 2006

This article identifies a challenge brought to us while facilitating a diversity workshop with adults in a school work setting. Our program involved using the video The Color of Fear as a centerpiece of a training to school district staff where the goals were to raise awareness and understanding of race, gender and class issues, increase understanding of power and privilege, and build alliances between people from diverse backgrounds. The challenge came from a white, male participant and involved issues of privilege, the intersections of race, class, and gender, and resistance to addressing diversity matters. Reflections of what worked and didn't work are offered as well as recommendations to other facilitators who will face similar challenges.
Lessons Learned in Developing a Research Partnership with the Transgender Community
Authors: Paxton Keisha Carr , Guentzel Heather , Trombacco Kellii
Published: June 2006

The challenge facing the authors was to develop a relationship with members of the Transgender community in a large urban city in order to develop research that would benefit this group. The situation is presented from the differing perspectives of the three women involved (one Transgender woman and two biological women); they provide their accounts of a meeting with key members of the Transgender community where the challenge became apparent. During the meeting, the issue of representation arose resulting in a discussion of whether the research agenda should be focused on a specific subgroup under the Transgender umbrella or be open to all members of this diverse and underserved group. Reflections on what was learned about the diversity of individuals under the Transgender umbrella and the lessons that helped them respond to the challenge are discussed.