bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrolysis and solubilization of corn gluten by Neutrase
Authors: Kılıç Apar Dilek , Özbek Belma
Published: October 2007

Hydrolysis and solubilization of corn gluten were performed using a commercial protease preparation Neutrase. The effects of substrate concentration, enzyme concentration, temperature, pH and hydrolysate amount on the degree of hydrolysis and solubility of corn gluten were investigated depending on processing time. Trials were conducted in a batch reactor and degrees of hydrolysis were computed using a pH‐stat method. Results show that solubility and degree of hydrolysis were almost linearly related in all process conditions applied except in the case of hydrolysate addition. Optimum conditions for hydrolysis and solubilization were obtained as 10 g L−1 protein concentration, 4 mL L−1 enzyme concentration, 45 °C and pH 6.5. The mechanism of the kinetics was explained by taking into consideration association binding between the enzyme and substrate. The kinetics of hydrolysis and solubilization for all experiments performed were represented by exponential association equations that have not been used in the literature before. Also, to illustrate the effect of process variables on hydrolysis and solubilization, some modelling studies were performed. Copyright © 2007 Society of Chemical Industry
Quorum sensing detected by atomic force microscopy imaging of corrals surrounding multicellular arrangement of bacteria
Authors: Teschke Omar , De Souza Elizabeth Fátima , Silva‐Stenico Maria Estela , Fiore Marli De Fátima , Etchegaray Augusto
Published: October 2007

Connectivity of the glycocalyx covering of small communities of Acidithiobacillus ferrooxidans bacteria deposited on hydrophilic mica plates was imaged by atomic force microscopy. When part of the coverage was removed by water rinsing, an insoluble structure formed by corrals surrounding each individual bacterium was observed. A collective ring structure with clustered bacteria (≥3) was observed, which indicates that the bacteria perceived the neighborhood in order to grow a protective structure that results in smaller production of exopolysaccharides material. The most surprising aspect of these collective corral structures was that they occur at a low bacterial cell density. The deposited layers were also analyzed by confocal Raman microscopy and shown to contain polysaccharides, protein, and glucoronic acid. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.
Histological evaluation on bone regeneration of dental implant placement sites grafted with a self‐setting α‐tricalcium phosphate cement
Authors: Nakadate Masayoshi , Amizuka Norio , Li Minqi , Freitas Paulo H.L. , Oda Kimimitsu , Nomura Shuichi , Uoshima Katsumi , Maeda Takeyasu
Published: October 2007

This study aimed to evaluate the histological characteristics of the new bone formed at dental implant placement sites concomitantly grafted with a self‐setting tricalcium phosphate cement (BIOPEX‐R®). Standardized defects were created adjacent to the implants in maxillae of 4‐week‐old male Wistar rats, and were concomitantly filled with BIOPEX‐R®. Osteogenesis was examined in two sites of extreme clinical relevance: (1) the BIOPEX‐R®‐grafted surface corresponding to the previous alveolar ridge (alveolar ridge area), and (2) the interface between the grafting material and implants (interface area). At the alveolar ridge area, many tartrate‐resistant acid phosphatase (TRAPase)‐reactive osteoclasts had accumulated on the BIOPEX‐R® surface and were shown to migrate toward the implant. After that, alkaline phosphatase (ALPase)‐positive osteoblasts deposited new bone matrix, demonstrating their coupling with osteoclasts. On the other hand, the interface area showed several osteoclasts initially invading the narrow gap between the implant and graft material. Again, ALPase‐positive osteoblasts were shown to couple with osteoclasts, having deposited new bone matrix after bone resorption. Transmission electron microscopic observations revealed direct contact between the implant and the new bone at the interface area, although few thin cells could still be identified. At both the alveolar ridge and the interface areas, newly formed bone resembled compact bone histologically. Also, concentrations of Ca, P, and Mg were much alike with those of the preexistent cortical bone. In summary, when dental implant placement and grafting with BIOPEX‐R® are done concomitantly, the result is a new bone that resembles compact bone, an ideal achievement in reconstructive procedures for dental implantology. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.
Simultaneous determination of gemcitabine and its main metabolite, dFdU, in plasma of patients with advanced non‐small‐cell lung cancer by high‐performance liquid chromatography‐tandem mass spectrometry
Authors: Marangon Elena , Sala Federica , Caffo Orazio , Galligioni Enzo , D'Incalci Maurizio , Zucchetti Massimo
Published: October 2007

Gemcitabine, 2′,2′‐difluoro‐2′‐deoxycytidine (dFdC) is a pyrimidine antimetabolite employed against several human malignancies. It undergoes intracellular activation to the pharmacologically active triphosphate form (dFdCTP) and metabolic inactivation to the metabolite 2′,2′‐difluorodeoxyuridine (dFdU). In order to investigate the human plasma pharmacokinetics of dFdC and dFdU, we developed and validated an HPLC‐MS/MS method, adding 2′‐deoxycytidine as internal standard and simply precipitating the protein with acetonitrile. The method requires a small sample (125 µl), and it is rapid and selective, allowing good resolution of peaks from the plasma matrix in only 7 min. It is sensitive, precise and accurate, with overall precision, expressed as CV%, always less than 10.0% for both analytes and high recovery: ≥ 80%. The limits of detection for dFdC and dFdU were 0.1 and 1.1 ng/ml, but considering the high concentrations in the plasma of patients investigated, we set the limit of quantitation at 20 ng/ml (0.08 µM) for dFdC and 250 ng/ml for dFdU, and validated the assay up to the dFdC concentration of 6.0 µg/ml (22.8 µM). The method was successfully used to study the drug pharmacokinetics in patients with advanced non‐small‐cell lung cancer in a phase II trial with gemcitabine administered as a fixed dose‐rate infusion. Copyright © 2007 John Wiley & Sons, Ltd.
Mass spectrometric study of the ionized C60: (γ‐Cyclodextrin)2 inclusion complex by collision induced dissociation
Authors: Greisch Jean‐François , Kyritsoglou Sam , Leyh Bernard , De Pauw Edwin
Published: October 2007

The water soluble inclusion complex [C60:(γ‐cyclodextrin)2] has been characterized using electrospray tandem mass spectrometry and collision induced dissociation. [C60:(γ‐cyclodextrin)2] ions were detected in the gas phase as doubly deprotonated, doubly protonated and doubly sodiated ions. The absence of monocharged complex ions following electronebulization is a likely consequence of the dimeric nature and structural symmetry of the inclusion complex. The collision induced dissociation of positive ions led exclusively to the observation of the protonated and sodiated cyclodextrin ions as well as their fragments. In negative ion mode the closed shell anion C60H− was the dominant fragment detected at low collision energies whereas at higher collision energies the signal corresponding to deprotonated cyclodextrin units becomes significant. Since C602− has been reported to have a nonnegligible basicity compared to C60 and C60−, it is likely that the proton transfer involved in the formation of the C60H− anion occurs following transfer of the two electrons from the deprotonated γ‐cyclodextrins to the fullerene. Finally, the charge state of the inclusion complex ions is also shown to affect the interaction strengths between its subunits. The relative stabilities of the three ionic species studied in gas phase following electronebulization are as follows: [C60:(γ‐cyclodextrin)2 + 2H]2+ < [C60:(γ‐cyclodextrin)2− 2H]2− < [C60:(γ‐cyclodextrin)2 + 2Na]2+. Copyright © 2007 John Wiley & Sons, Ltd.
Modified Z‐transform‐based FDTD algorithm for the anisotropic perfectly matched layer
Authors: Li Jianxiong , Dai Jufeng
Published: October 2007

A modified Z‐transform‐based algorithm for implementing the D‐H anisotropic perfectly matched layer (APML) is presented for truncating the finite‐difference time‐domain (FDTD) lattices. The main advantage is that, as compared with the previous Z‐transform‐based implementation for the D‐H APML, the proposed algorithm requires less auxiliary variables in the PML regions, and thus the memory requirement and the computational time are saved. These formulations are simple and independent of the material properties of the FDTD computational domain. Two numerical tests have been carried out to validate these formulations. Copyright © 2007 John Wiley & Sons, Ltd.
SPICE‐compatible stamps for semi‐discrete approximations of Maxwell's equations
Authors: Ramachandran Aravind , Ramachandran Anand , Cangellaris Andreas C.
Published: October 2007

This article presents the formulation of equivalent circuit stamps derived from the semi‐discrete form of Maxwell's equations. In particular, when a rectangular Yee's lattice is used for the spatial discretization of Faraday's and Ampere's laws, the stamps assume simple forms in terms of lumped circuit elements and dependent sources. It is shown that there is a very close relationship between the semi‐discrete Maxwell's system and the mesh analysis formalism of Kirchhoff's voltage and current laws. Boundary conditions, including a first‐order absorbing boundary condition, are extended to equivalent circuit descriptions. The utilization of the SPICE‐compatible equivalent circuit stamp formalism for the numerical solution of Maxwell's equations using SPICE is illustrated for the case of the calculation of the resonant frequencies of a perfectly conducting, rectangular cavity resonator. Copyright © 2007 John Wiley & Sons, Ltd.
Insulin‐like growth factors, angiopoietin‐2, and pigment epithelium–derived growth factor in the hypoxic retina
Authors: Sivakumar V. , Zhang Y. , Ling E. A. , Foulds W. S. , Kaur C.
Published: October 2007

As the response of the adult retina to hypoxia is likely to differ from that already established in the neonatal animal, this study was undertaken to examine the expression patterns of insulin‐like growth factor‐I (IGF‐I) and ‐II (IGF‐II), angiopoietin‐2 (Ang‐2), and pigment epithelium–derived growth factor (PEDF) in normal and hypoxic retinas of adult rats. In the latter, the retinas were examined from 3 hr to 14 days after hypoxic exposure. The mRNA and protein expression of IGF‐I, IGF‐II, Ang‐2, and PEDF in the retina was determined by real‐time RT‐PCR, Western blotting, and immunohistochemistry. The results showed up‐regulated expression of IGF‐I, IGF‐II, and Ang‐2 mRNA and protein in response to hypoxia, whereas PEDF expression was drastically reduced, suggesting that increased expression of IGF‐I and IGF‐II may be involved not only in neovascularization but also in neuroprotection in hypoxic conditions. The up‐regulation of Ang‐2, a proangiogenic factor, and the down‐regulation of PEDF, an antiangiogenic factor, is indicative of an imbalance between pro‐ and antiangiogenic factors in the hypoxic retina that may favor neovascularization. This was supported by the increased density of rat endothelial cell antigen–1 (RECA‐1) protein quantification and RECA‐1‐stained blood vessels in the inner retina. © 2007 Wiley‐Liss, Inc.
Inhibition of N‐cadherin and β‐catenin function reduces axon‐induced Schwann cell proliferation
Authors: Gess Burkhard , Halfter Hartmut , Kleffner Ilka , Monje Paula , Athauda Gagani , Wood Patrick M. , Young Peter , Wanner Ina B.
Published: October 2007

N‐cadherin and β‐catenin are involved in cell adhesion and cell cycle in tumor cells and neural crest. Both are expressed at key stages of Schwann cell (SC) development, but little is known about their function in the SC lineage. We studied the role of these molecules in adult rat derived SC‐embryonic dorsal root ganglion cocultures by using low‐Ca2+ conditions and specific blocking antibodies to interfere with N‐cadherin function and by using small interfering RNA (siRNA) to decrease β‐catenin expression in both SC‐neuron cocultures and adult rat‐derived SC monocultures. N‐cadherin blocking conditions decreased SC‐axon association and reduced axon‐induced SC proliferation. In SC monocultures, β‐catenin reduction diminished the proliferative response of SCs to the mitogen β1‐heregulin, and, in SC‐DRG cocultures, β‐catenin reduction inhibited axon‐contact‐dependent SC proliferation. Stimulation of SC cultures with β1‐heregulin increased total β‐catenin protein amount, phosphorylation of GSK‐3β and β‐catenin presence in nuclear extracts. In conclusion, our findings suggest a previously unrecognized contribution of β‐catenin and N‐cadherin to axon‐induced SC proliferation. © 2007 Wiley‐Liss, Inc.
F3/contactin‐related proteins in Helix pomatia nervous tissue (HCRPs): Distribution and function in neurite growth and neurotransmitter release
Authors: Milanese Chiara , Fiumara Ferdinando , Bizzoca Antonella , Giachello Carlo , Leitinger Gerd , Gennarini Gianfranco , Montarolo Pier Giorgio , Ghirardi Mirella
Published: October 2007

By using antibodies against mouse F3/contactin, we found immunologically related glycoproteins expressed in the nervous tissue of the snail Helix pomatia. Helix contactin‐related proteins (HCRPs) include different molecules ranging in size from 90 to 240 kD. Clones isolated from a cDNA expression library allowed us to demonstrate that these proteins are translated from a unique 6.3‐kb mRNA, suggesting that their heterogeneity depends on posttranslational processing. This is supported by the results of endoglycosidase F treatment, which indicate that the high‐molecular‐weight components are glycosylation variants of the 90‐kD chain. In vivo and in cultures, HCRPs antibodies label neuronal soma and neurite extensions, giving the appearance of both cytoplasmic and cell surface immunostaining. On the other hand, no expression is found on nonneural tissues. Functionally, HCRPs are involved in neurite growth control and appear to modulate neurotransmitter release, as indicated by the inhibiting effects of specific antibodies on both functions. These data allow the definition of HCRPs glycoproteins as growth‐promoting molecules, suggesting that they play a role in neurite development and presynaptic terminal maturation in the invertebrate nervous system. © 2007 Wiley‐Liss, Inc.
Different methods for estimating the mean radiant temperature in an outdoor urban setting
Authors: Thorsson Sofia , Lindberg Fredrik , Eliasson Ingegärd , Holmer Björn
Published: October 2007

The mean radiant temperature (Tmrt) is one of the most important meteorological parameters governing human energy balance. In this paper, three different methods of obtaining the Tmrt in an outdoor urban setting are compared. Method A is based on integral radiation measurements and angular factors, method B is based on measurements with a 38‐mm flat grey globe thermometer and in method C makes use of the Rayman 1.2 software is used. Measurements were performed in a large open square in a high latitude city—Göteborg, Sweden—during clear to overcast weather conditions in October 2005 and in July and August 2006.

Results show that the difference between Method A and Method B was generally relatively small. Most of the discrepancy, caused by rapid changes in radiation, temperature and wind speed was smoothed out using 5 min mean values. By systematically and empirically changing the mean convection coefficient, the accuracy of Method B was improved and a new equation expressing the Tmrt was obtained. With this new equation the 38 mm flat grey globe thermometer could successfully be used to estimate the Tmrt in an outdoor urban setting provided that the wind speed and the air and globe temperatures are measured accurately. The study also shows that the flat grey colour of the globe thermometer slightly underestimates the level of short‐wave radiation (i.e. sunshine). Method C works very well during the middle of the day in July, i.e. at high sun elevations. However, the model considerably underestimates the Tmrt in the morning and evening in July and during the whole day in October, i.e. at low sun elevations.

In outdoor urban settings where thermal comfort researchers or urban planners and designers require an easy and reliable method of estimating mean radiant temperature, the 38 mm flat grey globe thermometer provides a good and cheap solution. Copyright © 2007 Royal Meteorological Society
Chelation of Vanadium(IV) by a Natural and Edible Biopolymer Poly(γ‐glutamic acid) in Aqueous Solution: Structure and Binding Constant of Complex
Authors: Karmaker Subarna , Saha Tapan K.
Published: October 2007

The naturally occurring edible biopolymer poly(γ‐glutamic acid) (γ‐PGA) is shown to be an efficient chelating agent of vanadium(IV). The structure of poly(γ‐glutamic acid)oxovanadium(IV) (VO‐γ‐PGA) complex in solution has been analyzed by electron spin resonance and UV‐visible absorption spectra. The equatorial coordination sphere of vanadium(IV) is proposed to be [2 × carboxylate (2O)–VO–(OH2)2]. The binding isotherm is determined for suspensions of γ‐PGA in vanadium(IV) oxide sulfate (VS) solutions of different concentrations, and the data have been adjusted to fit the modified Langmuir equation. The maximum amount of vanadium bound per gram of γ‐PGA is estimated to be 141 mmol · g−1 with a binding constant of 22 L · g−1 at pH 3.

magnified image
Concurrent Differentiation of Marrow Stromal Cells to Osteogenic and Vasculogenic Lineages
Authors: Henderson James A. , He Xuezhong , Jabbari Esmaiel
Published: October 2007

When rat bone marrow stromal (BMS) cells were seeded on aligned type I collagen scaffolds and cultured in osteogenic media, they underwent simultaneous maturation and differentiation into osteogenic and vascular cell lineages. In addition, these cells produced mineralized matricellular deposits. BMS cells were seeded in Petri dish or the collagen scaffold, cultured in osteogenic media for 3, 6, and 9 d and subsequently processed for immunohistochemical and cytochemical analysis. Immunolocalization of lineage‐specific proteins were visualized using confocal microscopy and mRNA transcript analysis was performed by real‐time quantitative polymerase chain reaction (RT‐qPCR). The alkaline phosphatase activity and calcium content significantly increased over the observed period of time in an osteogenic medium. Sheets of abundant Pecam (CD31), Flk‐1 (VEGFR‐2), tomato lectin (TL/LEL), and α‐smooth muscle actin (α‐SMA) positive cells were observed in the collagen scaffolds. Nascent capillary‐like vessels were also seen amidst the osteoblasts in osteogenic culture, augmenting the maturation and differentiation of BMS cells into osteoblasts. In our in vitro study, concurrent differentiation of BMS cells, a heterogeneous cell population with multilineage differentiation potential, to osteogenic and vascular lineages demonstrated that the substrates (three‐dimensional (3‐D), collagen type I, aligned fibrils) had a profound effect on guiding the differentiation pathway of BMS cells.

magnified image
Quantifying Interactions between Cell Receptors and Adhesion Ligand‐Modified Polymers in Solution
Authors: Lee Kuen Yong , Kong Hyun Joon , Mooney David J.
Published: October 2007

Specific interactions between cells and cell‐interactive polymers in solution were investigated by the fluorescence resonance energy transfer (FRET) technique and rheological measurements. The green fluorescence emission was dramatically reduced when rhodamine‐stained cells were mixed with a fluorescein‐labeled RGD‐alginate solution, compared with those mixed with no RGD‐containing alginate solution, which indicated an occurrence of FRET and existence of specific interactions between the cells and the polymers in solution. Rheological measurements also confirmed the formation of ordered structures of cell/polymer mixtures, caused by specific cell‐polymer interactions. The FRET method was able to provide a useful means of investigating cell‐polymer interactions, both in a qualitative and quantitative manner, and this approach to monitoring and controlling specific interactions between cells and polymers could be useful in the design and tailoring of polymeric carriers for cells, as well as for biological drugs, especially for tissue engineering applications.

magnified image
Low Water Swelling and High Proton Conducting Sulfonated Poly(arylene ether) with Pendant Sulfoalkyl Groups for Proton Exchange Membranes
Authors: Pang Jinhui , Zhang Haibo , Li Xuefeng , Ren Dianfu , Jiang Zhenhua
Published: October 2007

Novel side‐chain‐type sulfonated poly(arylene ether) with pendant sulfoalkyl group copolymers (PSA‐SPAE‐6F) have been synthesized by direct copolymerization from a new sulfonated monomer, sodium 3‐(4‐(2,6‐difluorobenzoyl)phenyl)propane‐1‐sulfonate. The sulfonate content could be easily controlled by adjusting the sulfonated and the unsulfonated monomer feed ratio. The obtained copolymers all show good thermal and mechanical properties. It should be noted that the most highly sulfonated copolymer, PSA‐SPAE‐6F90 with an ion exchange capacity of 1.30 mequiv · g−1, shows a proton conductivity of 0.11 S · cm−1 and a water swelling ratio of only 12.9% at 100 °C, which indicates its high proton conductivity and excellent dimensional stability in hot water.

magnified image
Reversible Wettability Switching of Polyaniline‐Coated Fabric, Triggered by Ammonia Gas
Authors: Zhu Ying , Li Jiuming , He Haiyong , Wan Meixiang , Jiang Lei
Published: October 2007

A superhydrophobic polyaniline (PANI)‐coated fabric was prepared by in‐situ doping polymerization in the presence of perfluorosebacic acid (PFSEA) as the dopant. It is found that the PANI‐coated fabric undergoes a change in wettability from superhydrophobic (doped state) to superhydrophilic (de‐doped state) when it is exposed to ammonia gas. In particular, a reversible wettability of the PANI‐fabric is observed when it is doped with PFSEA and de‐doped with ammonium gas. It is proposed that the coordination effect of the pore structure of the polyester fabric, low surface energy of the PFSEA dopant, and reversible doping/dedoping characteristics of PANI results in the reversible wettability of the PANI‐coated fabric from superhydrophobicity to superhydrophilicity. Moreover, the tactic used here may provide a new method to monitor the toxic gas.

magnified image
Morphology and Electrical Conductivity of Poly(N‐vinylcarbazole)/Carbon Nanotubes Nanocomposite Synthesized by Solid State Polymerization
Authors: Maity Arjun , Ray Suprakas Sinha , Pillai Sreejarani K.
Published: October 2007

This communication describes the morphology and DC conductivity of poly(N‐vinylcarbazole) (PNVC)/multi‐walled carbon nanotubes (MWCNTs) nanocomposite. The nanocomposite has been synthesized by solid state in situ polymerization of N‐vinylcarbazole (NVC) monomer in the presence of MWCNTs at an elevated temperature. Fourier transform infrared (FT‐IR) spectroscopy studies reveal the ability of MWCNTs to promote the in situ polymerization of the NVC monomer. Field‐emission scanning electron microscopy (FE‐SEM) observations show the homogeneous wrapping of MWCNTs' outer surface by PNVC polymer. Transmission electron microscopy (TEM) images and Raman spectroscopy results support the SEM observations. Thermogravimetric analyses reveal a significant improvement of thermal stability of the nanocomposite sample in the higher temperature region. The resulting nanocomposite material exhibits a dramatic improvement of the DC conductivity inherent to the PNVC. For example, the DC conductivity increases from ≈5.9 × 10−13 S · cm−1 for PNVC to ≈12 S · cm−1 for the nanocomposite, an increase of about 1013 in the electrical conductivity.

magnified image
Bias‐free rainfall forecast and temperature trend‐based temperature forecast using T‐170 model output during the monsoon season
Authors: Bhardwaj Rashmi , Kumar Ashok , Maini Parvinder , Kar S.C. , Rathore L.S.
Published: October 2007

An objective forecasting system for medium‐range location‐specific forecasting of surface weather elements has been evolved at the National Centre for Medium Range Weather Forecasting, India (NCMRWF). The basic information used for this is the output from the T‐170 general circulation model (GCM). The direct model output (DMO) forecast is briefly explained along with the T‐170 model. The two important weather parameters considered in detail are rainfall and temperature. Both the parameters have biases. Techniques used for obtaining bias‐free rainfall forecasts and temperature trend‐based forecasts are explained in detail. These forecasts are obtained for all of the 602 districts of India. Finally, an evaluation of the accuracy of rainfall and temperature forecasts for selected districts for which the observed data could be obtained during the 2006 monsoon is presented. Copyright © 2007 Royal Meteorological Society
Climatic features of atmospheric stability in the Mediterranean region (1948–2006): spatial modes, inter‐monthly and inter‐annual variability
Authors: Lolis Christos J.
Published: October 2007

The predominant spatial modes of atmospheric stability over the Mediterranean region are revealed by applying factor analysis and cluster analysis on the daily 2.5° × 2.5° grid point values of K‐index for the period 1948–2006. At first, S‐mode factor analysis is applied on the K‐index time series in order to reduce the dimensionality of the data set. The k‐means cluster analysis is then applied to the factor scores time series, and the days are classified into 12 clusters with distinct and characteristic spatial distributions of the K‐index. The 12 spatial modes revealed are associated with the prevailing atmospheric circulation types and/or the thermal and humidity characteristics of the lower and the middle troposphere. The inter‐monthly variations of their frequency reveal the seasonal factors that contribute to their predominance. The seasonality of the 12 clusters shows that three of them prevail mainly in winter, three of them prevail mainly in summer, and the other six clusters present a relatively even seasonal distribution. The inter‐annual variations of their frequency exhibit considerable long‐term changes, providing also some possible indications of the oncoming climatic change. The continuous decrease of the typical high instability pattern of late spring and early summer and the recent increase of one of the typical high instability winter patterns provide some useful information about climate variability in the Mediterranean. Copyright © 2007 Royal Meteorological Society
A dose‐effect relationship of Ginkgo biloba extract to nerve regeneration in a rat model
Authors: Lin Haodong , Wang Huan , Chen Desong , Gu Yudong
Published: October 2007

The effect of Ginkgo biloba extract (EGb50) on nerve regeneration and its dose–effect relationship was investigated in a rat model. Sciatic nerve transection and repair was done in 120 Sprague‐Dawley rats. The animals were divided into four groups and given normal saline, low‐dose EGb50 (50 mg kg−1 d−1), moderate‐dose EGb50 (100 mg kg−1 d−1), and high‐dose EGb50 (200 mg kg−1 d−1), respectively. Electrophysiological, histological examinations, and functional evaluation were conducted at various postoperative intervals. Sensory regeneration distance, sciatic functional index (SFI), motor nerve conduction velocity, compound muscle action potential, axon regeneration index, and muscle mass were significantly higher in EGb50 groups than in saline groups. All but SFI of those parameters were better in high‐dose group when compared with those in moderate‐ and low‐dose groups. EGb50 has the effect of promoting regeneration of injured peripheral nerve.The higher the dose, the better the result. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Ziegler‐Natta/Metallocene Hybrid Catalyst for Ethylene Polymerization
Authors: Ahmadi Mostafa , Jamjah Roghieh , Nekoomanesh Mehdi , Zohuri Gholam Hossein , Arabi Hassan
Published: October 2007

A Ziegler‐Natta/metallocene hybrid catalyst was produced and utilized in the polymerization of ethylene with the aim of producing bimodal polyethylene. The MgCl2 adduct was prepared by a melt quenching method and Cp2ZrCl2 and TiCl4 catalysts were loaded, respectively, after treating the surface with TiBAl. The polymerization kinetics involved an induction period, followed by fragmentation and expansion of particles. SEM micrographs revealed that the spherical morphology was retained through the initial mild reaction conditions of induction period. The polymers produced showed bimodal molecular weight distribution patterns, suggesting that both components of the hybrid catalyst were active over the support.

magnified image
DEM analysis of the crack propagation in brittle clays under uniaxial compression tests
Authors: Vesga Luis F. , Vallejo Luis E. , Lobo‐Guerrero Sebastian
Published: October 2007

The discrete element method (DEM) has been used to study how cracks propagate in a continuum material (clay) subjected to a uniaxial compressive stress. The DEM results were compared with those obtained in laboratory samples. The laboratory tests used stiff clay samples with one crack inclined at varying angles with respect to the compressive stress. The DEM and the laboratory results compared very well. Also, the DEM proved to be a very successful approach for the visualization of secondary crack formations and its propagation in the simulated samples. Copyright © 2007 John Wiley & Sons, Ltd.
Transgenic mice with OIP‐1/hSca overexpression targeted to the osteoclast lineage develop an osteopetrosis bone phenotype
Authors: Shanmugarajan S , Irie K , Musselwhite C , Key Jr LL , Ries WL , Reddy SV
Published: October 2007

Regulatory mechanisms operative in bone‐resorbing osteoclasts are complex. We previously defined the Ly‐6 gene family member OIP‐1/hSca as an inhibitor of osteoclastogenesis in vitro; however, a role in skeletal development is unknown. In this study, we developed transgenic mice with OIP‐1/hSca expression targeted to the osteoclast lineage that develop an osteopetrotic bone phenotype. Humeri from OIP‐1 mice showed a significant increase in bone mineral density and bone mineral content. µCT analysis showed increased trabecular thickness and bone volume. OIP‐1 mice have dense sclerotic cortical bone with absence of spongiosa and inadequate formation of marrow spaces compared to wild‐type mice. Moreover, complete inhibition of osteoclasts and marrow cavities in calvaria suggests defective bone resorption in these mice. OIP‐1 mouse bone marrow cultures demonstrated a significant decrease (41%) in osteoclast progenitors and inhibition (39%) of osteoclast differentiation/bone resorption. Western blot analysis further demonstrated suppression of TRAF‐2, c‐Fos, p‐c‐Jun, and NFATc1 levels in RANKL‐stimulated osteoclast precursors derived from OIP‐1 mice. Therefore, OIP‐1 is an important physiological inhibitor of osteoclastogenesis and may have therapeutic value against bone loss in vivo. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Expression of KIT and PDGFR is associated with a good prognosis in neuroblastoma
Authors: Shimada Akira , Hirato Junko , Kuroiwa Minoru , Kikuchi Akira , Hanada Ryoji , Wakai Kimiko , Hayashi Yasuhide
Published: October 2007

Background

The clinical outcome of neuroblastoma (NB) depends on age, stage, and MYCN amplification. Receptor tyrosine kinases (RTKs) promote cell growth, migration, and metastasis in cancer cells, including NB. However, the correlation of the expression profile of RTKs with prognosis in NB remains controversial.

Procedure

Expression and mutation analysis of KIT, PDGFR, FLT3, RET, and TRKA mRNAs were performed in 24 NB cell lines and 40 tumor samples using RT‐PCR followed by direct sequencing. Immunohistochemical analysis of KIT and PDGFR protein expression was also examined in 38 paraffin sections of NB tumor samples.

Results

The expression of KIT, PDGFRβ, and FLT3 mRNA was associated with NB in patients under 1 year (P < 0.02) and TRKA expression (P < 0.001). The loss of expression of these kinases was associated with MYCN amplification (P < 0.02) and advanced stages of disease in patients over 1 year of age (P < 0.005). PDGFRα mRNA expression was detected in all cell lines and tumor samples, and RET mRNA expression was not associated with any clinical parameters. Immunohistochemistry results showed the similar findings. We did not find any activating mutations in KIT, PDGFR, FLT3, or RET. Notably, the GNNK− isoform of KIT was predominant in all cell lines and clinical samples.

Conclusion

Expression of KIT, PDGFRβ, and FLT3 was associated with a good prognosis in NB. The loss of expression of these RTKs might correlate to the disease progression of NB. Pediatr Blood Cancer 2008;50:213–217. © 2007 Wiley‐Liss, Inc.
A UK survey of treatment of dementia in Parkinson's disease
Authors: Leroi Iracema , Daniel Emily , Fletcher Peter , Hindle John , MacMahon Doug
Published: October 2007

Clinical experience with antidementia drugs in dementia in Parkinson's disease (PDD) is still limited and a lack of diagnostic criteria and specific screening tests further complicates clinical decision making. Here, the authors discuss the results of a postal survey sent to PD clinicians in the UK to assess their methods of diagnosis and use of antidementia drugs in PDD patients. Copyright © 2007 Wiley Interface Ltd
Identification and validation of novel CSF biomarkers for early stages of Alzheimer's disease
Authors: Hu Yan , Hosseini Ava , Kauwe John S. K. , Gross Julia , Cairns Nigel J. , Goate Alison M. , Fagan Anne M. , Townsend R. Reid , Holtzman David M.
Published: October 2007

The pathology of Alzheimer's disease (AD) begins years prior to clinical diagnosis. The development of antecedent biomarkers that indicate the presence of AD pathology and predict risk for decline in both cognitively normal and mildly impaired individuals will be useful as effective therapies are developed. While cerebrospinal fluid (CSF) markers such as amyloid‐β (Aβ) 42 and tau are useful, additional biomarkers are needed. To identify new markers, we utilized 2‐D difference gel electrophoresis (2‐D DIGE) of individual CSF samples from subjects with very mild AD versus controls after depletion of high‐abundant proteins. Protein spots displaying differential abundance between the two groups were identified with MS. A number of candidate biomarkers were identified in 18 gel features. Selected candidates were quantified in a larger clinical set using ELISA. The mean levels of α1‐antichymotrypsin (ACT), antithrombin III (ATIII), and zinc‐α2‐glycoprotein (ZAG) were significantly higher in the mild AD group, and the mean level of carnosinase 1 (CNDP1) was decreased. When these biomarkers are optimally combined, there is a strong trend toward greater specificity and sensitivity based on clinical diagnosis than when used individually. Our findings provide novel biomarker candidates for very mild and mild AD that can be further assessed as antecedent markers and predictors of clinical progression.
The proteomic approach in Parkinson's disease
Authors: Fasano Mauro , Bergamasco Bruno , Lopiano Leonardo
Published: October 2007

Parkinson's disease (PD) is a complex, multifactorial neurodegenerative disease affecting about 2% of the population over 65 years. Etiopathogenetic mechanisms of PD are not fully understood, although a number of factors contributing to the selective degeneration of substantia nigra neurons have been identified, including mitochondrial dysfunction, proteasomal impairment, oxidative stress, excitotoxicity, and inflammation. Although a global view of the disease at the molecular level can be obtained only from the biochemical analysis of the affected human tissue, difficulties in obtaining human specimens of the affected area have limited substantially the number of reports published to date. Therefore, cellular and animal models of the disease have been developed to investigate single factors contributing to disease pathogenesis, e.g., protein aggregation or altered dopamine homeostasis. In this review, we report how proteomic methodologies have been used so far to investigate cellular and animal models of PD, as well as to compare postmortem specimens of substantia nigra of affected patients to that of control subjects. Proteomic studies concur to highlight the role of a compromised antioxidant defense in PD pathogenesis. The proteomic approach in the investigation of etiopathogenetic mechanisms of PD is still at its beginning, however, the findings reviewed here should serve as a useful foundation to further work.
Proteomic strategies in multiple sclerosis and its animal models
Authors: Elkabes Stella , Li Hong
Published: October 2007

The early and precise diagnosis, the prognosis, and the clinical management of multiple sclerosis, remain a considerable challenge. In recent years, the development of novel and powerful proteomic techniques prompted the use of these approaches for the search of unique biomarkers in the cerebrospinal fluid of multiple sclerosis patients. A few studies have also utilized proteomics to delineate the profile of differentially expressed proteins in animal models of the human disease in order to gain global insights into affected pathways. The identification of differentially expressed proteins may be an initial step in the discovery of novel targets and mechanisms that play critical roles in the pathology of multiple sclerosis. Based on these findings, future investigations may elucidate the events leading to demyelination, axonal damage, and neurodegeneration, providing better insights into mechanisms governing the onset and progression of the disease. Although these proteomic studies provide valuable information, they are also faced with a number of challenges. The present review discusses some of the strengths and limitations of proteomic investigations as applied to multiple sclerosis.
Proteomics of Alzheimer's disease: Unveiling protein dysregulation in complex neuronal systems
Authors: Vosseller Keith
Published: October 2007

Alzheimer's disease (AD) and its progressive dementia is multifactorial, develops relatively sporadically, and involves multiple pathologies in the complex biological system of the brain. For these reasons, genetics alone is not likely to explain the molecular basis of this disease. Proteomics is contributing valuable information about the underlying molecular defects involved in AD development and progression, which includes oxidative damage to specific proteins, altered levels of synaptic components, and protein compositions of Aβ plaques and neurofibrillary tangles (pathological hallmarks of AD). However, emerging strategies in the field of proteomics which include more specific targeting of disease‐related anatomical regions, targeting of specific subcellular compartments of functional relevance, novel approaches for large scale identification of regulatory post‐translational modifications such as phosphorylation andO‐GlcNAc, improved chromatographic separations of peptides for more comprehensive analysis of samples, and high‐throughput quantitative strategies directly coupled with MS should greatly enhance the future of AD proteomics. The characterization of AD‐specific alterations in proteomes should provide further insight into mechanisms of disease development and progression, provide biomarkers predicting disease development, and provide novel targets for therapeutic intervention.
Studying the protein–protein interactions in the postsynaptic density by means of immunoabsorption and chemical crosslinking
Authors: Chang Chia‐Wei , Peng Sheng‐Chih , Cheng Wen‐Yao , Liu Szu‐Heng , Cheng Huei‐Hsuan , Huang San‐Yuan , Chang Yen‐Chung
Published: October 2007

Postsynaptic densities (PSDs), isolated from porcine cerebral cortices, are large disk‐shaped aggregates consisting of hundreds of different proteins. To study the protein–protein interactions in such complex supramolecules, we developed a procedure to break up the PSD's overall structure, while preserving some interactions between individual proteins. Using the resulting PSD sample and an indirect immunoabsorption procedure, PSD‐95 was isolated along with the α‐ and β‐subunits of calcium calmodulin‐dependent protein kinase II (CaMKIIα and CaMKIIβ), α‐tubulin, β‐tubulin, and Chapsyn110. Similarly, CaMKIIα was isolated along with CaMKIIβ, α‐tubulin, β‐tubulin, and small amounts of PSD‐95. The proteins isolated from PSDs treated with a cleavable bifunctional crosslinking reagent were further subjected to diagonal gel electrophoresis analysis, and the results indicated that CaMKIIα resides next to α‐tubulin in the PSD. Overall, the results obtained here suggest that within the PSD, large aggregates of CaMKIIα, CaMKIIβ, α‐tubulin, and β‐tubulin may occur that indirectly associate with PSD‐95 and Chapsyn110. Such a protein organization would allow interactions with F‐actin in the cytoplasm and with proteins, such asN‐methyl‐D‐aspartate receptors, which reside on the postsynaptic membrane. Furthermore, it would facilitate binding to proteins such as the various microtubule‐associated proteins that reside in the core region of the PSD.
Oligodendrocytes secrete exosomes containing major myelin and stress‐protective proteins: Trophic support for axons?
Authors: Krämer‐Albers Eva‐Maria , Bretz Niko , Tenzer Stefan , Winterstein Christine , Möbius Wiebke , Berger Hendrik , Nave Klaus‐Armin , Schild Hansjörg , Trotter Jacqueline
Published: October 2007

Oligodendrocytes synthesize the CNS myelin sheath by enwrapping axonal segments with elongations of their plasma membrane. Spatial and temporal control of membrane traffic is a prerequisite for proper myelin formation. The major myelin proteolipid protein (PLP) accumulates in late endosomal storage compartments and multivesicular bodies (MVBs). Fusion of MVBs with the plasma membrane results in the release of the intralumenal vesicles, termed exosomes, into the extracellular space. Here, we show that cultured oligodendrocytes secrete exosomes carrying major amounts of PLP and 2′3′‐cyclic‐nucleotide‐phosphodiesterase (CNP). These exosomes migrated at the characteristic density of 1.10−1.14 g/mL in sucrose density gradients. Treatment of primary oligodendrocytes with the calcium‐ionophore ionomycin markedly increased the release of PLP‐containing exosomes, indicating that oligodendroglial exosome secretion is regulated by cytosolic calcium levels. A proteomic analysis of the exosomal fraction isolated by sucrose density centrifugation revealed in addition to PLP and CNP, myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) as constituents of oligodendroglial exosomes, together with a striking group of proteins with proposed functions in the relief of cell stress. Oligodendroglial exosome secretion may contribute to balanced production of myelin proteins and lipids, but in addition exosomes may embody a signaling moiety involved in glia‐mediated trophic support to axons.
Molecular Dynamics Simulations of Polymer‐Bonded Explosives (PBXs): Modeling, Mechanical Properties and their Dependence on Temperatures and Concentrations of Binders
Authors: Xiao Jijun , Ma Xiufang , Zhu Wei , Huang Yucheng , Xiao Heming , Huang Hui , Li Jinshan
Published: October 2007

Two models, i.e. “covering” and “cutting” models, for the polymer‐bonded explosives (PBXs) were proposed for different researching aspects. Used for choosing polymeric binders, the “covering” models are mainly applied to find the relations of temperatures and concentrations respectively with elastic properties of the PBXs. The “cutting” model is especially used to describe the highly anisotropic behavior of 1,3,5‐triamino‐2,4,6‐trinitrobenzene crystals (TATB). These models were realized by using molecular dynamics methods. It is found that the ductility of crystalline TATB can be effectively improved by blending fluorine‐containing polymers in small amounts. The moduli for the PBXs decrease with increase in temperature and concentration of binders. Different crystalline surfaces interacting with the same polymer binder have different modulus‐decreasing effects due to the highly anisotropic behavior of TATB. The modulus‐decreasing effect for different crystalline surfaces ranking order is (010)≈(100)>(001).
On the Mechanism of Energy Transfer in the Plasma‐Propellant Interaction
Authors: Porwitzky Andrew J. , Keidar Michael , Boyd Iain D.
Published: October 2007

A coupled plasma sheath/ablation model is developed for electrothermal chemical gun applications. By combining a commonly employed collisional sheath model with a previous ablation model, the convective heat flux as a function of time to the propellant bed is determined for two potential electrothermal chemical gun propellants, XM39 and JA2. It is found that the convective heat flux varies smoothly from a nearly collisionless to a fully collisional regime over the short duration of the plasma pulse. The possibility of determining an accurate estimate of the amount of heat flux to the propellant bed due to radiation from the bulk plasma presents itself.
Studies of Detonation Characteristics of Aluminum Enriched RDX Compositions
Authors: Trzciński Waldemar A. , Cudziło Stanisław , Szymańczyk Leszek
Published: October 2007

Research on the effect of aluminum contents and of its particle size on detonation characteristics of RDX‐based compositions containing 15–60% aluminum was carried out. Measurements of detonation velocity for different charge diameters and confinements were performed. To measure the shock curvature of the detonation wave, X‐ray photography was applied. Unconfined charges and charges confined with a water envelope were tested. The radius of the detonation front curvature was determined. The cylinder test results were the basis for determination of the acceleration ability and energetic characteristics of the detonation products of the mixtures. The Gurney energy describing the acceleration ability was found. The detonation energy of the mixtures tested was also estimated from the cylinder test data.
Connecting string/Mtheory to the electroweak scale and to LHC data
Authors: Kumar P.
Published: October 2007

The Standard Model of particle physics explains (almost) all observed non‐gravitational microscopic phenomena but has many open theoretical questions. We are on the threshold of unravelling the mysteries of the Standard Model and discovering its extension. This could be achieved in the near future with the help of many experiments in particle physics and cosmology, the LHC in particular. Assuming that data confirming the existence of new physics beyond the Standard Model is obtained, one is left with the very important and challenging task of solving the “Inverse Problem”,viz. “How can one deduce the nature of the underlying (perhaps microscopic) theory from data?” This paper explores this question in detail, and also proposes an approach to address the problem in a meaningful way which could prove crucial to the possible solution to this problem in the future. The proposed approach has three aspects – a) To systematically study classes of microscopic (string/Mtheory) constructions to the extent that they could be connected to low energy physics (electroweak scale), b) To find patterns of experimental observables which are sensitive to the properties of the underlying theoretical constructions thereby allowing us to distinguish among different constructions, and c) To try to get insights about the qualitative features of the theoretical model from data in a bottom‐up approach which complements the top‐down approach and strengthens it as well. This paper studies all the above aspects in detail. The methods used and results obtained in this paper will hopefully be of great importance in solving the Inverse Problem.