bluuebunny/crossref_metadata_2025 huggingface dataset:
Tethered Epidermal Growth Factor Provides a Survival Advantage to Mesenchymal Stem Cells
Authors: Fan Vivian H. , Au Ada , Tamama Kenichi , Littrell Romie , Richardson Llewellyn B. , Wright John W. , Wells Alan , Griffith Linda G.
Published: January 2007

MSC can act as a pluripotent source of reparative cells during injury and therefore have great potential in regenerative medicine and tissue engineering. However, the response of MSC to many growth factors and cytokines is unknown. Many envisioned applications of MSC, such as treating large defects in bone, involve in vivo implantation of MSC attached to a scaffold, a process that creates an acute inflammatory environment that may be hostile to MSC survival. Here, we investigated cellular responses of MSC on a biomaterial surface covalently modified with epidermal growth factor (EGF). We found that surface-tethered EGF promotes both cell spreading and survival more strongly than saturating concentrations of soluble EGF. By sustaining mitogen-activated protein kinase kinase-extracellular-regulated kinase signaling, tethered EGF increases the contact of MSC with an otherwise moderately adhesive synthetic polymer and confers resistance to cell death induced by the proinflammatory cytokine, Fas ligand. We concluded that tethered EGF may offer a protective advantage to MSC in vivo during acute inflammatory reactions to tissue engineering scaffolds. The tethered EGF-modified polymers described here could be used together with structural materials to construct MSC scaffolds for the treatment of hard-tissue lesions, such as large bony defects.

Disclosure of potential conflicts of interest is found at the end of this article.
Cyclooxygenase-2-Derived Prostaglandin E2 Protects Mouse Embryonic Stem Cells from Apoptosis
Authors: Liou Jun-Yang , Ellent David P. , Lee Sang , Goldsby Jennifer , Ko Bor-Sheng , Matijevic Nena , Huang Jaou-Chen , Wu Kenneth K.
Published: January 2007

Little is known about prostaglandin synthesis and function in embryonic stem cells. We postulated that mouse embryonic stem (mES) cells possess enzymes to synthesize protective prostaglandins. Compared with differentiated adult cells, mES cells were less susceptible to H2O2-induced apoptosis. However, their apoptosis was enhanced by indomethacin or SC-236, a selective inhibitor of cyclooxygenase (COX)-2. Analysis of COX pathway enzymes by Western blotting revealed expression of COX-2 and cytosolic and microsomal prostaglandin E2 (PGE2) synthases. COX-1 and prostacyclin (PGI2) synthases were undetectable. mES cells produced PGE2 but not PGI2. Importantly, PGE2 rescued mES cells from apoptosis. To elucidate the signaling mechanism by which PGE2 inhibits apoptosis, we analyzed E-type prostaglandin (EP) receptors by Western blots. All EP isoforms were detected except EP4. Butaprost, a specific EP2 agonist, rescued mES cells from apoptosis, whereas sulprostone, an EP1/EP3 agonist, had no effect, suggesting selective interaction of PGE2 with EP2. The antiapoptotic effect of PGE2 was abrogated by Ly-294002 or wortmannin but not H-89 or a specific inhibitor of protein kinase A, suggesting signaling via phosphatidylinositol-3 kinase (PI-3K). Akt was constitutively active in mES cells, which were inhibited by indomethacin and rescued by PGE2. The rescuing effect of PGE2 was abrogated by Ly-294002. These results indicate that mES cells constitutively express COX-2 and PGE synthases and produce PGE2, which confers resistance to apoptosis via EP2-mediated activation of PI-3K to the Akt pathway.

Disclosure of potential conflicts of interest is found at the end of this article.
Correlation between radiological and clinical findings after anterior cruciate ligament reconstruction
Authors: Ninkovic Srdjan , Milicic Aleksandar , Savic Dragan , Stankovic Milan , Radic Srdjan , Milankov Miroslav
Published: January 2007

Introduction. In the last two decades, the gold standard for anterior cruciate ligament reconstruction is the bone-patellar tendon-bone graft procedure. Correct position of the bone-patellar tendon-bone graft significantly affects the postoperative knee stability. The aim of this study was to establish if and how clinically measured knee stability is associated with radiographic position of bone-patellar tendon-bone graft in the femoral and tibial bones. Material and methods. The prospective study included 39 patients, 30 men and 9 women. We analyzed and compared results of clinical and radiographic examinations prior to and 2 years following surgery. Results. The mean arthrometric difference between the anterior tibial movement prior to surgery was 11,2mm and 2,4mm (p<0,05) after surgery. The preoperative Tegner and Lysholm score was 1,49, and postoperative 8,23 (p<0,05). The preoperative Lysholm-Gillquist scale was 51,56 and postoperative 97,74 (p<0,05). The International Knee Documentation Committee (IKDC) scores were as follows: grade A in 32 patients (84.6%), grade B in 5 patients (12.8%), and grade C in 1 patient (2.6%). By comparison of IKDC scores and radiographic parameters (M1 - M10) of anterior-posterior and profile views, a statistical significance was found only between IKDC and M9 index (sagittal femoral index OR?/RR? x 100). Discussion. By using bone-patellar tendon-bone grafts, it is not possible to entirely achieve anatomical positions. Correct graft position within the bone tunnels is of great significance concerning knee stability after anterior cruciate ligament reconstruction. Conclusion. Correlation between radiological and clinical findings after anterior cruciate ligament reconstruction in our 39 patients shows that only the position of the graft affects the clinical outcome. Posterior graft location provides better clinical outcome and knee stability. On the other hand, anterior location is associated with worse postoperative IKDC scores, unstable knee and worse clinical outcome. .
Globular clusters and planetary nebulae kinematics and X-ray emission in the early-type galaxy NGC 5128
Authors: Samurovic S.
Published: January 2007

The estimates of the mass of the galaxy NGC 5128 based on the different mass tracers, globular clusters (GCs) and planetary nebulae (PNe), are presented. These estimates are compared with the estimate based on the X-ray methodology and it is found that the results for the mass (and mass-to-light ratio) for all three approaches are in very good agreement interior to 25 arcmin; beyond 25 arcmin the X-rays predict the mass which is too high with respect to the one found using GCs and PNe. Some possible explanations for this discrepancy were discussed. The Jeans equation is also solved and its predictions for the velocity dispersion are then compared with the observed values, which extend to ~8 effective radii in the case of the GCs and ~15 effective radii in the case of the PNe. It is found that interior to ~25 arcmin (~5 effective radii) dark matter does not dominate because the total mass-to-light ratio in the B band in solar units is less than 10. Based on the GCs and PNe beyond ~25 arcmin the total mass-to-light ratio increases to ~14 (at ~80 arcmin) which indicates the existence of dark matter in the outer regions of NGC 5128.
Analysis of early-stage sintering mechanisms of mechanically activated BaTiO3
Authors: Nikolic M.V. , Pavlovic V.P. , Pavlovic V.B. , Ristic M.M.
Published: January 2007

Barium-titanate powder was mechanically activated in a planetary-ball mill for 60 and 120 minutes. Non-isothermal sintering of non-activated and activated powder samples was investigated using a dilatometer in the temperature interval from room to 1380oC with three different heating rates (10, 20 and 30oC/min). Early-stage sintering mechanisms for all three types of samples were analyzed, showing significant differences between the non-activated and mechanically activated samples.
Nd pronounced anharmonicity in IR spectra of CaWO4 single crystals
Authors: Golubovic A. , Gajic R. , Dohcevic-Mitrovic Z. , Nikolic S.
Published: January 2007

CaWO4 and Nd:CaWO4 (0.8 at. % Nd) single crystals were grown from the melt by the Czochralski technique in air. The crystal growth parameters dc and ?c were calculated by equations from the hydrodynamics of the melt, whereas the rate of crystal growth was experimentally obtained. The infrared reflectance spectra of Nd:CaWO4 and CaWO4 single crystals were recorded in the range 50-5000 cm-1 at room and liquid nitrogen temperatures. Two oxygen Eu modes showed a splitting. That especially concerns one of them where the splitting is even more pronounced with the Nd doping. Instead of the earlier attempts based on a symmetry breaking or an activation of forbidden modes, we suggest that a strong anharmonicity is the source of this effect.
Simultaneous determination of metformin and glipizide in human plasma by liquid chromatography–tandem mass spectrometry
Authors: Ding Cun‐Gang , Zhou Zhen , Ge Qing‐Hua , Zhi Xiao‐Jin , Ma Li‐Li
Published: January 2007

A method has been developed for the simultaneous quantification of metformin (I) and glipizide (II) in human plasma. It is based on high‐performance liquid chromatography with electrospray ionization tandem mass (LC‐ESI‐MS/MS) spectrometric detection in positive ionization mode. Phenformin (III) and gliclazide (IV) were used as internal standards for I and II, respectively. The MS/MS detection was performed in multiple reaction monitoring (MRM) mode. The precursor‐product ion combinations of m/z 130 → 71, 446 → 321, 206 → 60 and 324 → 127 were used to quantify I, II, III and IV, respectively. This method was validated in the concentration ranges of 0.02–4 µg/mL for I and 0.004–0.8 µg/mL for II. It was utilized to support a clinical pharmacokinetic study after single dose oral administration of a combination of I and II. Copyright © 2007 John Wiley & Sons, Ltd.
The determination of raloxifene in rat tissue using HPLC
Authors: Yang Zhaoyong , He Xiaobo , Zhang Yueqin
Published: January 2007

We report a rapid and reliable HPLC‐UV method for determination of raloxifene, a kind of selective estrogen receptor modulator (SERM), in rat tissue. Proteins were precipitated by adding 200 µL of acetonitrile and 50 µL of methanol to 100 µL of the tissue homogenates, following vortex mixing and centrifugation. Separation was carried out on a reversed‐phase C18 column (150 × 4.6 mm, 5 µm) with a mobile phase of acetonitrile:0.05 m ammonium acetate (pH 4.0 ± 0.1; 33:67, v/v) at a flow rate of 1.0 mL/min. The UV detection wavelength was set at 289 nm and the temperature of column was kept at 23°C, without interference from endogenous tissue compounds. The calibration curve was linear from 0.0125 to 10.0 µg/mL with correlation coefficient of over 0.994, while the limit of quantification was 0.008 µg/mL. The intra‐ and inter‐day coefficients of variation were less than 10% (RSD). The recovery of assay was between 95.8 and 104.5%. Furthermore, the method was used to measure the concentration of raloxifene in rat tissue after a simple oral dose. The highest level was observed in liver, lung, spleen, then heart and kidney. The lowest level was found in brain. These results suggest that raloxifene distributes rapidly and moderately into tissues such as liver, lung and spleen. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid identification of Helicobacter pylori by capillary electrophoresis: an overview
Authors: Buszewski B. , Kłodzińska E. , Dahm H. , Różycki H. , Szeliga J. , Jackowski M.
Published: January 2007

Helicobacter pylori can cause gastritis and peptic ulcers and is directly associated with the development of gastric cancer. There are many types of diagnostic methods used to identification H. pylori (invasive and non‐invasive), but these methods usually require time‐consuming and laborious procedures and therefore are not capable of fast diagnosis in cases of emergency. This contribution describes the new achievements, interdisciplinary significance and some future directions in the application of capillary electrophoresis for determination of H. pylori. Copyright © 2007 John Wiley & Sons, Ltd.
An improved high‐throughput liquid chromatographic/tandem mass spectrometric method for terbinafine quantification in human plasma, using automated liquid–liquid extraction based on 96‐well format plates
Authors: Dotsikas Yannis , Apostolou Constantinos , Kousoulos Constantinos , Tsatsou Georgia , Loukas Yannis L.
Published: January 2007

A fully automated high‐throughput liquid chromatography/tandem mass spectrometry (LC‐MS/MS) method was developed for terbinafine quantification in human plasma. The plasma samples were treated by liquid–liquid extraction (LLE) in 2.2 mL 96‐deepwell plates. Terbinafine and the internal standard (IS) N‐methyl‐1‐naphthalenemethylamine were extracted from human plasma by LLE, using a mixture of methyl t‐butyl ether (MTBE)–hexane (70:30, v/v) as the organic solvent. All liquid transfer steps, including preparation of calibration standards and quality control samples, as well as the addition of the IS, were performed automatically by using robotic liquid handling workstations. After vortexing, centrifugation and freezing, the supernatant organic solvent was evaporated and reconstituted in a small volume of a reconstitution solution. Sample analysis was performed by reversed‐phase LC‐MS/MS, with positive ion electrospray ionization, using multiple reaction monitoring (MRM). The method had a very short sample preparation time and a chromatographic run time of 2.2 min. It was proved to have excellent sensitivity, specificity, accuracy as well as inter‐ and intraday precision for the quantification of terbinafine in human plasma. The calibration curve was linear for the range of concentrations 5.0–2000.0 ng/mL. The proposed method was applied to the rapid and reliable determination of terbinafine in a bioequivalence study after per os administration of 250 mg tablet formulations of terbinafine. Copyright © 2007 John Wiley & Sons, Ltd.
A solid‐phase extraction method for high‐performance liquid chromatographic determination of salvianolic acid B in rabbit plasma: application to pharmacokinetic study
Authors: Ma Yueming , Wang Tianming
Published: January 2007

A sensitive solid‐phase extraction/high‐performance liquid chromatographic method with ultraviolet detection was established for the analysis of salvianolic acid B in rabbit plasma. The analyte was separated on a reversed‐phase column with trifluoroacetic acid–methanol–acetonitrile (70:10:20, v/v/v) as mobile phase at a flow rate of 1 mL/min, and ultraviolet detection at 315 nm. The calibration curve for salvianolic acid B was linear over the range 35–1400 µg/L with coefficients of correlation >0.999. The inter‐day and intra‐day precisions of analysis were <15%, and assay accuracy ranged from 95.3 to 109.1%. This method is suitable for determining salvianolic acid B in plasma and thus investigating the pharmacokinetics of salvianolic acid B. Copyright © 2007 John Wiley & Sons, Ltd.
Semi‐micro column high‐performance liquid chromatography with UV detection for quantification of aspirin and salicylic acid and its application to patients' sera administered with low‐dose enteric‐coated aspirin
Authors: Ohwaki Yuichi , Yamane Tomoko , Ishimatsu Takashi , Wada Mitsuhiro , Nakashima Kenichiro
Published: January 2007

A simultaneous determination of aspirin (ASA) and its metabolite, salicylic acid (SA), in human serum by a semi‐micro column HPLC‐UV was developed. A relatively small size of serum sample (100 µL) containing ASA and SA was cleaned up by a simple solid phase extraction. A good separation of ASA and SA could be achieved within 25 min using a semi‐micro ODS column with an eluent of MeOH/0.7 mm phosphoric acid solution (pH 2.5) = 50:50 (v/v). The calibration curves for ASA and SA showed good linearity (r = 0.999) with the detection limits 114 and 38 ng/mL at a signal‐to‐noise ratio of 3, respectively. ASA and SA in patients' sera administered with low‐dose enteric‐coated aspirin were determined, and the concentration ranges obtained for ASA and SA were 1.2–2.2 and 0.5–57.3 µg/mL, respectively. Copyright © 2007 John Wiley & Sons, Ltd.
Development of a LC‐ESI/MS/MS assay for the quantification of vanillin using a simple off‐line dansyl chloride derivatization reaction to enhance signal intensity
Authors: Beaudry Francis , Ross Andréanne , Vachon Pascal
Published: January 2007

Vanillin is responsible for producing the familiar smell of vanilla. Vanillin has many similarities with other flavor phenolic compounds and could potentially show similar pharmacological activity. A previously published analytical method was adapted, developed and tested. Vanillin was extracted from rat plasma using protein precipitation with acetone. Prior to LC‐ESI/MS/MS analysis, an aliquot of the supernatant was used to proceed to the derivatization of vanillin and the internal standard with dansyl chloride to enhance signal intensity in positive electrospray mode. The chromatography was performed on a 100 × 2.1 mm C8 column and an isocratic mobile phase composed of 75:25 acetonitrile:0.5% formic acid in water with a flow rate fixed at 500 µL/min. A linear (weighted 1/concentration) relationship was used to perform the calibration over an analytical range of 10–10,000 ng/mL. The intra‐batch precision and accuracy at the limit of quantitation (10 ng/mL), medium (500 ng/mL) and high (10,000 ng/mL) concentrations were 10.7, 7.0 and 7.2% and 103.5, 108.0 and 100.1%, respectively. The observed recovery was greater than 87% and no significant ionization suppression or matrix effect was observed. This LC‐ESI/MS/MS method for the determination of vanillin in rat plasma provided results within generally accepted criteria used for bioanalytical assay. Copyright © 2007 John Wiley & Sons, Ltd.
Direct detection method of oligosaccharides by high‐performance liquid chromatography with charged aerosol detection
Authors: Inagaki Shinsuke , Min Jun Zhe , Toyo'oka Toshimasa
Published: January 2007

A simple and rapid detection method of oligosaccharides using high‐performance liquid chromatography with a charged aerosol detection (HPLC‐CAD) was studied. The direct detection of a sialylglycopeptide (SGP) derived from egg yolk was accomplished by HPLC‐CAD using an amido‐silica column, and its limit of detection was 0.40 pmol [signal‐to‐noise ratio (S/N) = 3]. The sensitivity of this method was lower than that of the fluorescence detection; however, the method showed approximately 5 times higher sensitivity than that using the conventional UV absorbance detection. Furthermore, this method was used for the analysis of the acid hydrolysis products of SGP. Monosialo‐ and asialo‐oligosaccharides as well as free sialic acid were detected without using fluorescent derivatization. These results indicate that the present method is a new tool for the analysis of oligosaccharides. Copyright © 2007 John Wiley & Sons, Ltd.
Development and validation of an RP‐HPLC‐UV method for the determination of BOL‐303225‐A, a new coumarin‐based anti‐inflammatory drug, in rat plasma
Authors: Maltese Adriana , Maugeri Francesco , Ward Keith W. , Bucolo Claudio
Published: January 2007

A simple and rapid high‐performance liquid chromatographic method was developed and validated for the analysis in rat plasma of BOL‐303225‐A, a new coumarin‐based anti‐inflammatory drug. Liquid–liquid extraction was used for sample preparation. Chromatographic separation was achieved on a C18 column using acetonitrile and water containing 1% triethylamine pH 3.5, adjusted with orthophosphoric acid (35.5:64.5 v/v) as mobile phase. The UV detector was set at 324 nm. The method proved to be linear (r2 > 0.99) and precise (RSD < 7%) over the concentration range 29–940 ng/mL, and was suitable for the support of pharmacokinetic studies in rats. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of six bioactive components of Saussurea katochaete by capillary electrophoresis
Authors: Yue Mei‐E , Li Ya , Shi Yan‐Ping
Published: January 2007

The simultaneous determination of 3,4‐dimethoxy‐3′‐hydroxy propiophenone, 5‐hydroxy‐7‐methoxy coumarin, 7‐hydroxy coumarin, 3′,5′‐dimethoxy apigenin, apigenin and 4‐hydroxy cinnamic acid in the extract of S. katochaete has been investigated by capillary electrophoresis for the first time. The six active components were completely separated within 10 min in 20 mM Na2HPO4 buffer at pH 11.00 with 10% (v/v) methanol and detected at 214 nm. The applied voltage was 15 kV and the temperature was kept at 25°C. The effects of buffer pH, the concentration of Na2HPO4 and the concentration of methanol on the separation efficiency were studied systematically. The regression equations revealed good linear relationships (correlation coefficients were 0.9987–0.9998) between the peak area of each analyte and its concentration. The relative standard deviations (RSD) of migration time and peak areas were <1.63 and <4.03%, respectively. The application of this method for the separation and determination of the six bioactive components in S. katochaete was reported. The contents of the six analytes ranged from 0.023 to 0.131 mg/g and recoveries ranged from 94.7 to 104.8%. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of hydroxysafflor yellow A in rat plasma and tissues by high‐performance liquid chromatography after oral administration of safflower extract or safflor yellow
Authors: Li Yi , Zhang Zhao‐yang , Zhang Jin‐lan
Published: January 2007

A simple and reproducible HPLC method for quantification of hydroxysafflor yellow A (HSYA) in rat plasma and tissues after oral administration of safflower extract or safflor yellow (SY) was developed. Sample preparation was achieved by protein precipitation of plasma and tissue homogenates with three volumes of methanol. p‐Hydroxybenzaldehyde was used as the internal standard (IS). HSYA and IS were separated on a Hypersil BDS‐C18 column with a gradient elution system composed of acetonitrile and aqueous acetic acid. UV detection was used at 320 nm. The calibration curves were linear in all matrices (r2 > 0.999) in the concentration ranges 0.51–101.36 µg/mL for plasma, 12.27–2454.46 µg/g for intestines and 0.96–192.20 µg/g for lung. The intra‐day and inter‐day precision were all less than 12.5%, and the extract recovery was in the range 64.1–103.7% with RSD less than 15.6% for HSYA in all matrices. The method was used successfully to quantify HSYA in rat plasma and tissue samples to support a pharmacokinectic study. Copyright © 2007 John Wiley & Sons, Ltd.
Rapid quantification of lisinopril in human plasma by liquid chromatography/tandem mass spectrometry
Authors: Qin Weiwei , Zhang Zunjian , Tian Yuan , Xu Fengguo , Wang Na , Chen Yun
Published: January 2007

An assay based on protein precipitation and liquid chromatography/tandem mass spectrometry (LC‐MS/MS) has been developed and validated for the quantitative analysis of lisinopril in human plasma. After the addition of enalaprilat as internal standard (IS), plasma samples were prepared by one‐step protein precipitation using perchloric acid followed by an isocratic elution with 10 mm ammonium acetate buffer (pH adjusted to 5.0 with acetic acid)–methanol (70:30, v/v) on a Phenomenex Luna 5µC18 (2) column. Detection was performed on a triple‐quadrupole mass spectrometer utilizing an electrospray ionization (ESI) interface operating in positive ion and selected reaction monitoring (SRM) mode with the precursor to product ion transitions m/z 406→246 for lisinopril and m/z 349→206 for enalaprilat. Calibration curves of lisinopril in human plasma were linear (r = 0.9973−0.9998) over the concentration range 2–200 ng/mL with acceptable accuracy and precision. The limit of detection and lower limit of quantification in human plasma were 1 and 2 ng/mL, respectively. The validated LC‐MS/MS method has been successfully applied to a preliminary pharmacokinetic study of lisinopril in Chinese healthy male volunteers. Copyright © 2007 John Wiley & Sons, Ltd.
Characteristics of offenders referred to a medium secure NHS personality disorder service: the first five years
Authors: Milton John , Duggan Conor , McCarthy Lucy , Costley‐White Amanda , Mason Lauren
Published: January 2007

Background As new services for offenders with personality disorder emerge in the UK, there is interest in the methods of assessments and characteristics of patients admitted.

Aim To evaluate use of selection criteria for admission to a dedicated personality disorder service within medium secure hospital provision in the UK, and to test for features that discriminate between those admitted and those rejected.

Method A structured multidisciplinary assessment was administered to offenders referred to a new personality disorder service in a medium secure psychiatric unit. The evaluation included self‐report and observer ratings across a range of domains including categorical axis I disorders and axis II disorders, dimensional assessment of personality and ratings of intellect and risk.

Results Sixty‐eight male offenders were assessed, of whom 47 were offered admission. No differences were found between those accepted or rejected on demographic, offence and most clinical characteristics. Axis I comorbidity was high in both groups (over 90%). There was no indication of staff overriding exclusion criteria but men who were accepted had greater extraversion and conscientiousness on the NEO‐FFI.

Conclusion Staff screening men for suitability for admission to this new specialist medium security hospital unit stayed true to given exclusion criteria in their decision not to offer a bed. Characteristics with face value as qualities necessary for engagement in treatments appeared to influence positive choices. Next steps will be to test the validity of choice with outcome studies. Copyright © 2007 John Wiley & Sons, Ltd.
Reversible Assembly and Disassembly of Gold Nanoparticles Directed by a Zwitterionic Polymer
Authors: Ding Ya , Xia Xing‐Hua , Zhai He‐Sheng
Published: January 2007

Herein, we have successfully introduced the stimuli‐response concept into the controllable synthesis of gold nanoparticles (AuNPs) with designed properties. We used a pH‐responsive zwitterionic polymer that acted as a template and a stabilizer. Gold colloids prepared in situ from the polymer solution have a narrow size distribution of about 5 nm. The assembly and disassembly of AuNPs can be finely tuned by modulating the net charges of the zwitterionic polymer so that they are either positive or negative as a function of the solution pH. Different aggregates and colors appear on altering the solution pH. In acidic solutions, gold colloids form large symmetrical aggregates, while the AuNPs disperse in solutions with a pH≈9.6. However, as the solution pH increases (>9.6), needle‐like aggregates with a small interparticle distances are formed. On the basis of TEM, SEM, 1H NMR and UV/Vis measurements, we attribute pH‐triggered aggregation and color changes of the gold colloids to the ionization process and conformational change of the polymer. The ionization process governs the choice of ligand anchored on the surface of AuNPs, and the conformational change of the polymer modulates the interspaces between AuNPs. The present approach, which is based on a rational design of the physicochemical properties of the template used in the synthesis process, provides a powerful means to control the properties of the nanomaterial. Furthermore, the colorimetric readout can be visualized and applied to future studies on nanoscale switches and sensors.
Effect of Protonation and Interaction with Anions on a Lead(II) Complex with a Lateral Macrobicycle Containing a Phenol Schiff‐Base Spacer
Authors: Esteban‐Gómez David , Platas‐Iglesias Carlos , Avecilla Fernando , de Blas Andrés , Rodríguez‐Blas Teresa
Published: January 2007

The macrobicycle receptor L4, derived from 1,10‐diaza‐15‐crown‐5 incorporating a phenol Schiff‐base spacer, forms stable complexes with lead(II). In [Pb(L4)(ClO4)](ClO4)·CH3CN (1), the lead(II) ion is asymmetrically placed at the one end of the macrobicyclic cavity, because of the intramolecular hydrogen bonding interaction that occurs between an imine nitrogen atom and the phenol group. This asymmetric position of the metal ion inside the macrobicyclic cavity induces chirality in this system. Variable temperature 1H NMR spectroscopic experiments indicate that the asymmetric coordination of the metal ion inside the macrocyclic cavity is maintained in acetonitrile solution, but a translocation of the PbII ion from one end of the macrobicyclic cavity to the second one occurs. This dynamic behaviour, which corresponds to the interconversion between the two possible enantiomeric forms of the complex, is fast on the NMR timescale at 320 K but slow at low temperatures, and we have estimated an activation barrier of ΔG‡ = 68 ± 2 kJ mol–1. We have also studied the effect of the protonation on 1 by NMR and UV/Vis spectroscopy in CH3CN solutions at room temperature, finding that diprotonation causes demetallation of the complex without receptor destruction, recovering L4 in its protonated form. On the other hand, the interaction of compound 1 with anions such as NO3– and SCN– has been evaluated by using spectrophotometric titrations in acetonitrile solution, finding log K values of 5.83(1) for NO3– and 6.27(2) forSCN–. The [Pb(L4)]2+, [Pb(L4)(NO3)]+, [Pb(L4)(NCS)]+ and [Pb(L4)(SCN)]+ systems were characterized by means of density functional theory calculations (DFT) performed by using the B3LYP model, and the coordination geometry as well as the role of the PbII lone pair has been investigated and discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Polymer‐Supported Dioxido‐MoVI Complexes as Truly Functional Molybdenum Oxotransferase Model Systems
Authors: Heinze Katja , Fischer Andreas
Published: January 2007

A truly functional model system for molybdenum oxotransferases provides evidence for all biologically realistic intermediates, namely mononuclear MoVI, MoV and MoIV species. Dinucleation to EPR‐silent [MoV2O3] species prevailing in homogeneous solution is suppressed by immobilising the active species to a polymeric support by two‐point attachment.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Polymorphic occurrence and crystallization rates of tristearin/tripalmitin mixtures under non‐isothermal conditions
Authors: Himawan Chrismono , MacNaughtan William , Farhat Imad A. , Stapley Andrew G. F.
Published: January 2007

The effect of composition and cooling rate on polymorphic occurrence and crystallization rates in binary mixtures of tripalmitoylglycerol (PPP) and tristearoylglycerol (SSS) has been studied using differential scanning calorimetry (DSC), light microscopy and X‐ray diffraction under constant cooling rates. In general, β and β' polymorphs were observed at cooling rates of 0.5 K/min and less, and the α form at higher cooling rates. Double peaks were observed in the DSC exotherms of mixtures containing more than 30% SSS. The X‐ray data showed that, when cooling at 0.5 K/min, the double peaks correspond to the crystallization of the α and β' forms. However, when cooling at 1 K/min and higher, the double peaks appear to arise from the crystallization of two α phases – one PPP rich and the other SSS rich. Light microscopy experiments also show two distinct morphologies, which corroborates this view. The apparent SSS‐rich phase crystallizes as irregular spherulites whereas the apparent PPP‐rich phase forms a fine crystal mass. Analyses of thermograms relating to the α form show that the amount of supercooling at the onset of crystallization is virtually independent of composition. However, peak width information shows that, once started, pure‐component samples crystallize faster than mixtures.
Evaluation of partially hydrogenated methyl esters of soybean oil as biodiesel
Authors: Moser Bryan R. , Haas Michael J. , Winkler Jill K. , Jackson Michael A. , Erhan Sevim Z. , List Gary R.
Published: January 2007

Biodiesel, an alternative fuel derived from vegetable oils or animal fats, continues to undergo rapid worldwide growth. Specifications mandating biodiesel quality, most notably in Europe (EN 14214) and the USA (ASTM D6751), have emerged that limit feedstock choice in the production of biodiesel fuel. For instance, EN 14214 contains a specification for iodine value (IV; 120 g I2/100 g maximum) that eliminates soybean oil as a potential feedstock, as it generally has an IV >120. Therefore, partially hydrogenated soybean oil methyl esters (PHSME; IV = 116) were evaluated as biodiesel by measuring a number of fuel properties, such as oxidative stability, low‐temperature performance, lubricity, kinematic viscosity, and specific gravity. Compared to soybean oil methyl esters (SME), PHSME were found to have superior oxidative stability, similar specific gravity, but inferior low‐temperature performance, kinematic viscosity, and lubricity. The kinematic viscosity and lubricity of PHSME, however, were within the prescribed US and European limits. There is no universal value for low‐temperature performance in biodiesel specifications, but PHSME have superior cold flow behavior when compared to other alternative feedstock fuels, such as palm oil, tallow and grease methyl esters. The production of PHSME from refined soybean oil would increase biodiesel production costs by US$ 0.04/L (US$ 0.15/gal) in comparison to SME. In summary, PHSME are within both the European and American standards for all properties measured in this study and deserve consideration as a potential biodiesel fuel.
ω‐Alkyne‐Mono‐ and Diphosphonates – Synthesis and Sonogashira Cross‐Coupling Reaction with Aryl Halides
Authors: Delain‐Bioton Lise , Villemin Didier , Jaffrès Paul‐Alain
Published: January 2007

A convergent approach to functionalise aromatic compounds with a linker terminated by a phosphonate group is reported. The starting point of this strategy is the synthesis of five new ω‐alkyne‐phosphonates. The linker between the phosphonate group and the alkyne part is either an alkyl or an ether chain. This strategy is based on the use of the phosphonate group as the anchoring point for the attachment of organic compounds onto alumina and the alkyne group, which is used to functionalise aryl halide compounds by a Sonogashira cross‐coupling. The use of 1,10‐phenanthroline as substrate illustrates the application of this strategy to an aromatic ligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Effects of rock fragments incorporated in the soil matrix on concentrated flow hydraulics and erosion
Authors: Rieke‐Zapp D. , Poesen J. , Nearing M. A.
Published: January 2007

Rock fragments can act as a controlling factor for erosional rates and patterns in the landscape. Thus, the objective of this study is to better understand the role that rock fragments incorporated into the soil matrix play in concentrated flow hydraulics and erosion. Laboratory flume experiments were conducted with soil material that was mixed with rock fragments. Rock fragment content ranged from 0 to 40 per cent by volume. Other treatments were slope (7 and 14%) and flow discharge (5·7 and 11·4 l min−1). An increase in rock fragment content resulted in lower sediment yield, and broader width of flow. Rock fragment cover at the soil surface, i.e. surface armour, increased with time in experiments with rock fragments. Flow energy was largely dissipated by rock fragment cover. For more turbulent flow conditions, when roughness elements were submerged in the flow, hydraulic roughness was similar for different rock fragment contents. In experiments with few or no rock fragments a narrow rill incised. Flow energy was dissipated by headcuts. Total sediment yield was much larger than for experiments with rock fragments in the soil. Adding just a small number of rock fragments in the soil matrix resulted in a significant reduction of sediment yield. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative biorelevant profiling of material microstructure within 3D porous scaffolds via multiphoton fluorescence microscopy
Authors: Liu Er , Treiser Matthew D. , Johnson Patrick A. , Patel Parth , Rege Aarti , Kohn Joachim , Moghe Prabhas V.
Published: January 2007

This study presents a novel approach, based on fluorescence multiphoton microscopy (MPM), to image and quantitatively characterize the microstructure and cell–substrate interactions within microporous scaffold substrates fabricated from synthetic biodegradable polymers. Using fluorescently dyed scaffolds fabricated from poly(DTE carbonate)/poly(DTO carbonate) blends of varying porosity and complementary green fluorescent protein‐engineered fibroblasts, we reconstructed the three‐dimensional distribution of the microporous and macroporous regions in 3D scaffolds, as well as cellular morphological patterns. The porosity, pore size and distribution, strut size, pore interconnectivity, and orientation of both macroscale and microscale pores of 3D scaffolds were effectively quantified and validated using complementary imaging techniques. Compared to other scaffold characterizing techniques such as confocal imaging and scanning electron microscopy (SEM), MPM enables the acquisition of images from scaffold thicknesses greater than a hundred microns with high signal‐to‐noise ratio, reduced bulk photobleaching, and the elimination of the need for deconvolution. In our study, the morphology and cytoskeletal organization of cells within the scaffold interior could be tracked with high resolution within the limits of penetration of MPM. Thus, MPM affords a promising integrated platform for imaging cell–material interactions within the interior of polymeric biomaterials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Enhanced retention of polymer physical characteristics and mechanical strength of 70:30 poly(L‐lactide‐co‐D,L‐lactide) after ethylene oxide sterilization
Authors: McManus Anastasia J. , Moser Rodney C. , Dabkowski Rhiannon B. , Thomas Kevin A.
Published: January 2007

This study examined the effect of ethylene oxide (EtO) and electron beam (e‐beam) irradiation on the properties of 70:30 poly(L‐lactide‐co‐D,L‐lactide). The effects of sterilization upon the polymer physical characteristics and strength retention of the material were examined, both initially and after being subjected to real time ageing. Commercially available 70:30 poly(L‐lactide‐co‐D,L‐lactide) material was fabricated into rectangular, cylindrical, screw, and sheet designs, and tested in compression, shear, or tension. Sterilization of 70:30 poly(L‐lactide‐co‐D,L‐lactide) by ethylene oxide had a nearly negligible effect on the physical properties of the polymer, regardless of specimen size or manufacturing technique. The molecular weight and inherent viscosity of the specimens decreased by ∼3% after sterilization by EtO. However, sterilization of 70:30 poly(L‐lactide‐co‐D,L‐lactide) by e‐beam irradiation resulted in immediate changes to some of the physical properties of the polymer. Specimens sterilized by e‐beam irradiation displayed an immediate decrease in inherent viscosity of ∼67% as compared to the respective nonsterile samples. The immediate decrease in inherent viscosity and molecular weight with e‐beam irradiation required ∼39 weeks of real time ageing of the EtO sterilized parts. At all time points investigated in the present study, the strength retention of the EtO sterilized devices equaled or exceeded that of the e‐beam irradiated samples. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
New insights on the bridge carbon–carbon bond in propellanes: A theoretical study based on the analysis of the electron localization function
Authors: Polo Victor , Andres Juan , Silvi Bernard
Published: January 2007

The nature of the bonding between bridgehead carbon atoms (Ca, Ca′) as well as the ring strain in a family of 10 propellanes formed by three‐, four‐, or five‐member rings: [1.1.1] (I), [2.1.1] (II), [3.1.1] (III), [2.2.1] (IV), [3.2.1] (V), [2.2.2] (VI), [3.3.1] (VII), [3.2.2] (VIII), [3.3.2] (IX), and [3.3.3] (X) are studied by means of the electron localization function (ELF) at the DFT level (B3LYP/cc‐pVTZ). The ELF analysis of smaller propellanes (I, II, and III) reveals the coexistence of two resonance forms: one with a nonbonding electron pair partially delocalized between Ca and Ca′ atoms outside the cage (ionic) and the other with a bridge bond between the same atoms (covalent). The weights of each form are calculated according to the ELF‐basin populations, yielding 94, 88, and 53% for the ionic structure of I, II, and III, respectively, while larger propellanes (IV–X) present only the covalent form. The question of the s‐character of the bridge bond is addressed by dissecting the bridge‐bond ELF basin into the molecular orbital contributions. Finally, σ‐aromaticity associated to surface electron delocalization has been analyzed by means of nucleus‐independent chemical shift (NICS) calculations. The results point out that the stability of the fused ring structure of propellanes I, II, and III, can be assigned to the remarkable σ‐aromaticity of the involved three‐member rings. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007
Reduced chondrogenic potential of adipose tissue derived stromal cells correlates with an altered TGFβ receptor and BMP profile and is overcome by BMP‐6
Authors: Hennig Thea , Lorenz Helga , Thiel Angela , Goetzke Katrin , Dickhut Andrea , Geiger Florian , Richter Wiltrud
Published: January 2007

Recent interest has focused on mesenchymal stem cells (MSC) for tissue engineering and regenerative therapy of cartilage defects. MSC originating from adipose tissue (ATSC) are attractive as they are easily available and abundant. They have similar properties like bone marrow derived MSC (BMSC), except for a reduced chondrogenic potential under standard culture conditions driven by TGFβ. Aim of this study was to search for possible differences explaining the reduced differentiation capacity of ATSC and to eliminate it by adaptation of induction protocols. Expanded MSC were analyzed for their growth factor and related receptor repertoire and ATSC spheroid cultures were supplemented with BMP‐2,‐4,‐6,‐7, TGFβ, FGFa, FGFb, IGF‐1, and PTHrP alone or in combination with TGFβ. In contrast to BMSC, ATSC showed reduced expression of BMP‐2, ‐4, and ‐6 mRNA and did not express TGFβ‐receptor‐I protein. Consistent with this, increased concentrations of TGFβ did not improve chondrogenesis of ATSC. BMP6 treatment induced TGFβ‐receptor‐I expression and combined application of TGFβ and BMP‐6 eliminated the reduced chondrogenic potential of ATSC inducing a gene expression profile similar to differentiated BMSC. Like in BMSC, chondrogenesis of ATSC was associated with hypertrophy according to premature collagen Type X expression, upregulation of alkaline‐phosphatase activity and in vivo calcification of spheroids after ectopic transplantation in SCID mice. In conclusion, a distinct BMP and TGFβ‐receptor repertoire may explain the reduced chondrogenic capacity of ATSC in vitro, which could be compensated by exogenous application of lacking factors. Further studies should now be directed to induce chondrogenesis in the absence of hypertrophy. J. Cell. Physiol. 211: 682–691, 2007. © 2007 Wiley‐Liss, Inc.
Bifurcated hydrogen‐bonding effect on the shielding and coupling constants in trifluoroacetyl pyrroles as studied by 1H, 13C and 15N NMR spectroscopy and DFT calculations
Authors: Afonin Andrei V. , Ushakov Igor A. , Mikhaleva Al'bina I. , Trofimov Boris A.
Published: January 2007

According to the 1H, 13C and 15N NMR spectroscopic data and DFT calculations, bifurcated NH···N and NH···O intramolecular hydrogen bond is shown to be present in 2‐trifluoroacetyl‐5‐(2′‐pyridyl)‐pyrrole. This bifurcated hydrogen bond causes an increase in the absolute size of the 1J(N,H) coupling constant by about 6 Hz, and the deshielding of the bridge proton by 2 ppm. DFT calculations show that the influence of the NH···N and NH···O intramolecular hydrogen bonds on the 1J(N,H) coupling and proton shielding is almost additive, although the components of the bifurcated hydrogen bond slightly weaken each other. In 2‐trifluoroacetyl‐5‐(2′‐pyridyl)‐pyrrole, the coupling constants involving the fluorine and the NH covalent bond nuclei depend dramatically on the spatial position of the pyridine ring. The pyridine ring rotation operates as a quantum switch controlling the spin information transfer between the 19F and 15N nuclei, as well as the proton. Copyright © 2007 John Wiley & Sons, Ltd.
Complete 1H and 13C NMR assignments of sesquiterpene glucosides from Ixeris sonchifolia
Authors: Na ZeyEi , Cho Jeong‐Yong , Lee Hyoung Jae , Chung Jin Ho , Park Ki Deok , Lee Young Ju , Shin Soo Cheol , Rim Yo Sup , Park Keun‐Hyung , Moon Jae‐Hak
Published: January 2007

Four sesquiterpene glucosides were isolated from Ixeris sonchifolia Hance. The structure of a new compound (1) was assigned as 9β‐monohydroxy‐2,12‐dioxo‐guaia‐3,11(13)‐dien‐1α,5α,6β,7α,9β,10αH‐12,6‐olide‐9‐O‐β‐D‐ glucopyranoside (ixerinoside). In addition, unambiguous and complete assignments of 1H NMR chemical shifts for crepidiaside A (2), ixerin Z (3), and 11,13α‐dihydroixerin Z (4) are presented. The assignments were achieved by two‐dimensional NMR (gCOSY, gHSQC, gHMBC, NOESY) and one‐dimensional nuclear Overhauser effect (NOE) experiments. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative characterization of hemodynamic properties and vasculature dysfunction of high‐grade gliomas
Authors: Nagesh Vijaya , Chenevert Thomas L. , Tsien Christina I. , Ross Brian D. , Lawrence Theodore S. , Junck Larry , Cao Yue
Published: January 2007

Aberrations in tumor and peritumoral vasculature may not be distinguishable by cerebral blood flow (CBF) or cerebral blood volume (CBV) alone. The relationships between CBF and CBV were examined to estimate vasculature‐specific hemodynamic characteristics. Twenty glioma patients were studied with dynamic susceptibility T2*‐weighted MRI [(dynamic contrast‐enhanced magnetic resonance imaging (DSC‐MRI)] before and during week 1 and 3 of radiotherapy (RT). CBF and CBV were calculated from DSC‐MRI, and relationships between the two were evaluated: the physiological measure of mean transit time (MTT) = CBV/CBF; empirical fitting using the power law CBV = constant × (CBF)β. Three different tissue types were assessed: the Gd‐enhancing tumor volume (GEV); non‐enhanced abnormal tissue located beyond GEV but within the abnormal hyperintense region on FLAIR images (NEV); normal tissue in the hemisphere contralateral to the tumor (CNT). The effects of tissue types, CBV magnitudes (low, medium and high), before and during RT, on MTT and β were analyzed by analysis of variance (ANOVA). The MTT and β for the three tissue types were significantly different (p < 0.009). MTT increased from CNT (1.60 s) to NEV (1.93 s) to GEV (2.28 s) (p < 0.0005). β was significantly greater in GEV (1.079) and NEV (1.070) than in CNT (1.025). β increased with increasing CBV magnitude while MTT was independent of CBV magnitude. There was a significant decrease in MTT of NEV and GEV during week 3 of RT compared with pre‐RT values for all CBV magnitudes. There was a significant increase in β during RT in the tumor and peritumor. Progressive abnormalities in vasculature and hemodynamic characteristics of the vascular bed were delineated, with significant disorder in the tumor but mild abnormality in peritumoral tissue. Copyright © 2007 John Wiley & Sons, Ltd.