bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of serotonin in the trunk of Metaperipatus blainvillei (Onychophora, Peripatopsidae): Implications for the evolution of the nervous system in Arhropoda
Authors: Mayer Georg , Harzsch Steffen
Published: January 2008

Onychophora (“velvet worms”) are a key taxon in the discussion of arthropod phylogeny. Studies that analyze neuroanatomical characters against a phylogenetic background have recently provided new insights into this debate. However, to date only a few studies on nervous system organization, particularly in the trunk, are available in Onychophora. To close this gap and to compare the onychophoran nervous system with that of other bilaterians, we have analyzed the pattern of serotonin‐like immunoreactivity in Metaperipatus blainvillei (Peripatopsidae). In addition to confirming previous histological observations, our experiments revealed many new aspects of nervous system organization in Onychophora. The serotonergic nervous system of M. blainvillei consists of five longitudinal nerve strands (the paired dorsolateral nerves, the heart nerve, and the paired ventral cords), which are interconnected at regular intervals by ring commissures as well as median commissures. The ring commissures are absent in the leg‐bearing regions. In addition to the main nerve tracts, there are several extensive fiber networks innervating the integument, the nephridial organs, and the body musculature. The leg nerves and nephridial nerves represent the only strictly segmental neuronal structures. We conclude that the general architecture of the onychophoran nervous system in the trunk closely resembles the orthogonal organization that is present in various other groups of Bilateria, which suggests that the arthropod nervous system is derived from such an orthogonal pattern. This finding implies that the “rope ladder‐like” nervous system may have arisen independently in Panarthropoda and Annelida and does not represent a synapomorphy of these groups. J. Comp. Neurol. 507:1196–1208, 2008. © 2008 Wiley‐Liss, Inc.
Physical Properties of Biopolymers Assessed by Optical Tweezers: Analysis of Folding and Refolding of Bacterial Pili
Authors: Andersson Magnus , Axner Ove , Almqvist Fredrik , Uhlin Bernt Eric , Fällman Erik
Published: January 2008

Bacterial adhesion to surfaces mediated by specific adhesion organelles that promote infections, as exemplified by the pili of uropathogenic E. coli, is studied mostly at the level of cell–cell interactions and thereby reflects the averaged behavior of multiple pili. The role of pilus rod structure has therefore only been estimated from the outcome of experiments involving large numbers of organelles at the same time. It has, however, lately become clear that the biomechanical behavior of the pilus shafts play an important, albeit hitherto rather unrecognized, role in the adhesion process. For example, it has been observed that shafts from two different strains, even though they are similar in structure, result in large differences in the ability of the bacteria to adhere to their host tissue. However, in order to identify all properties of pilus structures that are of importance in the adhesion process, the biomechanical properties of pili must be assessed at the single‐molecule level. Due to the low range of forces of these structures, until recently it was not possible to obtain such information. However, with the development of force‐measuring optical tweezers (FMOT) with force resolution in the low piconewton range, it has lately become possible to assess forces mediated by individual pili on single living bacteria in real time. FMOT allows for a more or less detailed mapping of the biomechanical properties of individual pilus shafts, in particular those that are associated with their elongation and contraction under stress. This Mi‐ nireview presents the FMOT technique, the biological model system, and results from assessment of the biomechanical properties of bacterial pili. The information retrieved is also compared with that obtained by atomic force microscopy.
Accuracy of herpes simplex virus detection in liquid‐based (SurePath) Papanicolaou tests: A comparison with polymerase chain reaction
Authors: Aslan Deniz L. , Pambuccian Stefan E. , Prekker Frances L. , Schacker Timothy W. , Southern Peter , Savik Kay , McKeon Dan , Gulbahce H. Evin
Published: January 2008

A review of our institution's Papanicolaou test records over an 11‐yr period showed that liquid‐based Papanicolaou tests (LBPTs) had a significantly higher frequency of diagnoses of Herpes simplex virus (HSV)‐related cellular changes compared to conventional Papanicolaou smears (77/302,841, 0.026% vs. 56/376,173, 0.015%, P = 0.002). To investigate the accuracy of the diagnosis of HSV by LBPT, we performed conventional polymerase chain reaction (PCR) on the residual samples from 258 prospectively collected LBPT and real‐time PCR using a different primer set on a subset of 40 LBPT. Conventional PCR was positive in 22 of 22 cases diagnosed of HSV, 1 of 2 cases diagnosed as suspicious for HSV, and none of 234 LBPT without a cytologic HSV diagnosis. Real‐time PCR was positive in 8 of 8 cases diagnosed as HSV and none of the 32 controls. We conclude that LBPT allows an increased detection of HSV that is highly accurate. Diagn. Cytopathol. 2008;36:94–103. © 2008 Wiley‐Liss, Inc.
Diagnosis of myeloid sarcoma involving salivary glands by fine‐needle aspiration cytology and flow cytometry: Report of four cases
Authors: Cai Guoping , Levine Pascale , Şen Filiz
Published: January 2008

Myeloid sarcoma involving salivary glands is extremely rare. Here, we report four cases of this rare occurrance, diagnosed by fine‐needle aspiration biopsy. All of four patients had previous diagnoses of myeloid neoplasms. They presented with a solitary mass in the parotid or submandibular salivary gland. The cytological evaluation of the aspirates revealed scattered salivary gland acini admixed with dispersed atypical cells. In three cases, the atypical cells appeared to be heterogenous, intermediate to large in size, and have folded nuclei with fine chromatin. In another case the atypical cells were monotonous and had round nuclei with fine chromatin. The myeloid lineage of the atypical cells was demonstrated by flow cytometric analysis. High clinical suspicion, careful cytological evaluation, and concurrent ancillary studies are essential for establishing a diagnosis of myeloid sarcoma. Diagn. Cytopathol. 2008;36:124–127. © 2008 Wiley‐Liss, Inc.
Phosphaturic mesenchymal tumor diagnosed by fine‐needle aspiration and core biopsy: A case report and review of literature
Authors: Policarpio‐Nicolas Maria Luisa , Abbott Todd E. , Dalkin Alan C. , Bennett‐Wick Jane , Frierson Henry F.
Published: January 2008

Oncogenic (tumor‐induced) osteomalacia is a rare paraneoplastic syndrome of phosphate wasting that is frequently associated with phosphaturic mesenchymal tumor (PMT). As the cytologic features of this tumor apparently have not been reported, we describe the fine‐needle aspiration (FNA) findings for PMT that arose from the gluteal soft tissue in a patient with hypophosphatemia and multiple fractures secondary to osteomalacia. Smears from the computerized tomography (CT)‐guided FNA showed groups of spindle cells having elongated nuclei, fine to moderately coarsely granular chromatin, inconspicuous nucleoli, and delicate cytoplasm. Marked nuclear atypia, mitotic figures, and necrosis were absent. The differential diagnosis included a variety of benign and malignant spindle cell neoplasms such as monophasic synovial sarcoma, leiomyoma, peripheral nerve sheath tumor, fibrosarcoma, and, less likely, metastatic melanoma and sarcomatoid carcinoma. The bland‐appearing cytologic features of a spindle cell tumor in a patient with osteomalacia should suggest the diagnosis of PMT. Diagn. Cytopathol. 2008;36:115–119. © 2008 Wiley‐Liss, Inc.
Lithium and Zinc Complexes of C‐ and N‐Functionalized (2‐Pyridylmethyl)amines
Authors: Koch Christian , Kahnes Marcel , Schulz Martin , Görls Helmar , Westerhausen Matthias
Published: January 2008

The addition reaction of benzophenone with lithium (2‐pyridylmethyl)(tert‐butyldimethylsilyl)amide yields dimeric1‐lithoxy‐1,1‐diphenyl‐2‐(2‐pyridyl)‐2‐(trialkylsilylamino)ethane (1) with formation of a C–C bond. C‐Functionalized 2‐(pyridylmethyl)amines are accessible via the reaction of N‐(2‐pyridylmethylidene)phenylamine with diethylmalonate giving 2,2‐bis(ethoxycarbonyl)‐1‐(phenylamino)‐1‐(2‐pyridyl)ethane (2) which eliminates aniline upon heating yielding diethyl 2‐(2‐pyridylmethylidene)malonate (3). The addition of piperidine leads to the formation of the Michael type adduct 2,2‐bis(ethoxycarbonyl)‐1‐piperidyl‐1‐(2‐pyridyl)ethane (4) which can be deprotonated with metal‐organic reagents such as Zn[N(SiMe3)2]2, Zn[CH(SiMe3)2]2, LiN(SiMe3)2, and NaN(SiMe3)2 leading to 2,2‐bis(ethoxycarbonyl)‐1‐piperidyl‐1‐(2‐pyridyl)ethane‐2‐yl complexes of zinc (5 and 6), lithium (7), and sodium (8). N‐Functionalization can be achieved via the reaction of (2‐pyridylmethyl)(trialkylsilyl)amine with benzoyl chloride giving N‐(2‐pyridylmethyl)benzoylamine (9). Lithiation and subsequent salt metathesis reaction with another equivalent of benzoyl chloride yields N‐(2‐pyridylmethyl)dibenzoylamine (10). The addition reaction of ZnCl2 with N‐(2‐pyridylmethyl)(diphenylmethylidene)amine (11) forms colorless crystalline [(Py–CH2N=CPh2)ZnCl2] (12). The addition of benzoyl chloride leads to N‐(diphenylchloromethyl)‐N‐(2‐pyridylmethyl)benzoylamine (13). Addition of ZnCl2 leads to the formation of solvent‐separated [(2‐pyridylmethyl)(benzoylamino)diphenylcarbonium] [(tetrahydrofuran)trichlorozincate] (14). The X‐ray crystal structures of 1, 4 to 7, 9, 12, and 14 are discussed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Stereoselective Desymmetrizations by Recombinant Whole Cells Expressing the Baeyer–Villiger Monooxygenase from Xanthobacter sp. ZL5: A New Biocatalyst Accepting Structurally Demanding Substrates
Authors: Rial Daniela V. , Bianchi Dario A. , Kapitanova Petra , Lengar Alenka , van Beilen Jan B. , Mihovilovic Marko D.
Published: January 2008

In this work the substrate profile and stereoselectivity of engineered whole cells overexpressing the Baeyer–Villiger monooxygenase from Xanthobacter sp. ZL5 with respect to biotransformations of prochiral substrates is characterized. This enzyme catalyzes the desymmetrization of cyclic ketones bearing different chemical features with stereoselectivity similar to that obtained with a related protein fromAcinetobacter as a prototype representative of the cyclohexanone monooxygenase enzyme cluster. Moreover, this biocatalyst is able to convert sterically demanding substrates previously not transformed by other enzymes with excellent enantioselectivities. These results expand the repertoire of optically pure lactones accessible by whole‐cell biotransformation processes, which are useful intermediates for the synthesis of natural and bioactive products. In addition, we observed a remarkable epoxidation reaction of a non‐activated C=C bond catalyzed by this monooxygenase.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis, Ion Complexation Study, and 3D‐Structural Analysis of Peptides Based on Crown‐Carrier, Cα‐Methyl‐L‐DOPA Amino Acids
Authors: Wright Karen , Anddad Rachid , Lohier Jean‐François , Steinmetz Vincent , Wakselman Michel , Mazaleyrat Jean‐Paul , Formaggio Fernando , Peggion Cristina , De Zotti Marta , Keiderling Timothy A. , Huang Rong , Toniolo Claudio
Published: January 2008

Selected series of terminally protected model peptides to the hexamer level, based on four novel, crown‐ether containing Cα‐methyl‐L‐DOPA (L‐Mdp) amino acid residues, namely L‐Mdp[15‐C‐5], L‐Mdp[18‐C‐6], L‐Mdp[benzo‐24‐C‐8] and L‐Mdp[(S)‐Binol‐20‐C‐6], combined with either L‐Ala or L‐Ala/Aib or Gly/Aib, were synthesized by solution methods. An ESI‐MS analysis of their alkali metal cation complexation ability was carried out. Their FTIR absorption, 1H NMR, ECD, and VCD spectroscopic properties suggest that all of these crowned amino acids are strong inducers of (left‐handed) β‐turns and 310‐helical structures.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Ruthenium‐Catalyzed Allenyl Carbamate Formation from Propargyl Alcohols and Isocyanates
Authors: Haak Edgar
Published: January 2008

Ruthenium complexes of redox‐coupled cyclopentadienone ligands catalyze the formation of allenyl carbamates from propargyl alcohols and isocyanates. This efficient and atom‐economical process represents the first catalytic access to allenyl carbamates, compounds of high synthetic potential. The reaction needs an acidic co‐catalyst and can be performed at room temperature. In addition, new (cyclopentadienone)iron and ‐ruthenium complexes were synthesized, and mechanistic aspects regarding catalytic transformations of propargyl systems with ruthenium catalysts are obtained. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A projection method‐based model for dam‐ and dyke‐break flows using an unstructured finite‐volume technique: Applications to the Malpasset dam break (France) and to the flood diversion in the Red River Basin (Vietnam)
Authors: Shi Yu‐e , Nguyen Kim Dan
Published: January 2008

A numerical model is presented for simulating dam‐break flows and flood diversions. The model is based on a projection method, which consists of combining the momentum and continuity equations to establish a Poisson‐type equation for the water surface level. The computed domain is discretized by finite volumes on an unstructured grid. A second‐order upwind scheme coupled with a least‐square technique is used for handling advection terms. The accuracy, stability and reliability of the present model are verified by comparing numerical results with observed data for the Malpasset dam‐break event. An application of flood diversion in Red River Basin is also reported. Copyright © 2008 John Wiley & Sons, Ltd.
A novel non‐upwind, interconnected, multi‐grid, overlapping numerical procedure for problems involving fluid flow
Authors: Abou‐Ellail Mohsen M. M. , Li Yuan , Tong Timothy W.
Published: January 2008

A novel numerical procedure for heat, mass and momentum transfer in fluid flow is presented. The new scheme is passed on a non‐upwind, interconnected, multi‐grid, overlapping (NIMO) finite‐difference algorithm. In 2D flows, the NIMO algorithm solves finite‐difference equations for each dependent variable on four overlapping grids. The finite‐difference equations are formulated using the control‐volume approach, such that no interpolations are needed for computing the convective fluxes. For a particular dependent variable, four fields of values are produced. The NIMO numerical procedure is tested against the exact solution of two test problems. The first test problem is an oblique laminar 2D flow with a double step abrupt change in a passive scalar variable for infinite Peclet number. The second test problem is a rotating radial flow in an annular sector with a single step abrupt change in a passive scalar variable for infinite Peclet number. The NIMO scheme produced essentially the exact solution using different uniform and non‐uniform square and rectangular grids for 45 and 30° angle of inclination. All other schemes were unable to capture the exact solution, especially for the rectangular and non‐uniform grids. The NIMO scheme was also successful in predicting the exact solution for the rotating radial flow, using a uniform cylindrical‐polar coordinate grid. Copyright © 2008 John Wiley & Sons, Ltd.
An anisothermal, compressible, piezoviscous model for journal‐bearing lubrication
Authors: Bollada P. C. , Phillips T. N.
Published: January 2008

Compressibility plays a significant role in the load‐bearing capacity of a journal bearing. This paper offers more realistic modelling of the lubricant than presented in an earlier paper (Int. J. Numer. Meth. Fluids 2007; 55(11):1091–1120) by including variable sound speed, piezoviscosity and both temperature and shear thinning. The load‐bearing capacity of the journal bearing is sensitive to all of these attributes of the model, but piezoviscosity is found to be the most significant. The equations of motion are adapted to a moving frame to explore the stability of the journal in a more dynamic setting and it is found that a free journal using this model will spiral outward exhibiting half speed whirl. The model is discretized in 2D, semi‐implicitly in time and using the spectral element method in space. Numerical results are presented that highlight the contributions of the different elements in the model to journal stability. Copyright © 2008 John Wiley & Sons, Ltd.
Assessment of regularized delta functions and feedback forcing schemes for an immersed boundary method
Authors: Shin Soo Jai , Huang Wei‐Xi , Sung Hyung Jin
Published: January 2008

We present an improved immersed boundary method for simulating incompressible viscous flow around an arbitrarily moving body on a fixed computational grid. To achieve a large Courant–Friedrichs–Lewy number and to transfer quantities between Eulerian and Lagrangian domains effectively, we combined the feedback forcing scheme of the virtual boundary method with Peskin's regularized delta function approach. Stability analysis of the proposed method was carried out for various types of regularized delta functions. The stability regime of the 4‐point regularized delta function was much wider than that of the 2‐point delta function. An optimum regime of the feedback forcing is suggested on the basis of the analysis of stability limits and feedback forcing gains. The proposed method was implemented in a finite‐difference and fractional‐step context. The proposed method was tested on several flow problems, including the flow past a stationary cylinder, inline oscillation of a cylinder in a quiescent fluid, and transverse oscillation of a circular cylinder in a free‐stream. The findings were in excellent agreement with previous numerical and experimental results. Copyright © 2008 John Wiley & Sons, Ltd.
DEM prediction of particle flows in grinding processes
Authors: Cleary P. W. , Sinnott M. D. , Morrison R. D.
Published: January 2008

Particle size reduction is a critical unit process in many industries including mineral processing, cement, food processing, pigments and industrial minerals and pharmaceuticals. The aim is to take large feed material and as efficiently as possible reduce the size of the particles to a target size range. Over time, a very large range of equipment has been developed to perform this for many materials and in many different conditions. Discrete element method (DEM) modelling is a computational tool that can allow detailed exploration of the particle flow and breakage processes within comminution equipment and can assist in developing a clearer and more comprehensive understanding of the detailed processes occurring within. In this paper, we examine the particle and energy flows in representative examples of the equipment used in many grinding processes. We study a 36′ semi‐autogenous mill used in primary grinding for mineral processing, a ball mill used for cement clinker grinding, a grinding table also used for cement grinding, a tower mill used for fine grinding both in mineral processing and for industrial minerals and finally for an Isamill, which is used for ultra‐fine grinding in mineral processing. Copyright © 2008 John Wiley & Sons, Ltd.
Identification of a novel and myeloid specific role of the leukemia‐associated fusion protein DEK‐NUP214 leading to increased protein synthesis
Authors: Ageberg Malin , Drott Kristina , Olofsson Tor , Gullberg Urban , Lindmark Anders
Published: January 2008

The t(6;9)(p22;q34) chromosomal translocation is found in a subset of patients with acute myeloid leukemia (AML). The translocation results in a fusion between the nuclear phosphoprotein DEK and the nucleoporin NUP214 (previously CAN). The mechanism by which the fusion protein DEK‐NUP214 contributes to leukemia development has not been identified, and disruptions of normal cellular functions by DEK‐NUP214 have previously not been described. In the present study, a novel effect of the DEK‐NUP214 fusion protein is demonstrated. Our findings reveal a substantial increase in global protein synthesis in DEK‐NUP214 expressing cells. Furthermore, we conclude that this effect is not the result of dysregulated transcription but merely due to increased translation. Consistent with the association with AML, the increased protein synthesis mediated by DEK‐NUP214 is restricted to cells of the myeloid lineage. Analysis of potential mechanisms for regulating protein synthesis shows that expression of DEK‐NUP214 correlates to the phosphorylation of the translation initiation protein, EIF4E. The present data provide evidence that increase of translational activity constitutes a mechanism by which the leukemogenic effect of DEK‐NUP124 may be mediated. © 2008 Wiley‐Liss, Inc.
Expression and prognostic significance of different mRNA 5′‐end variants of the oncogene EVI1 in 266 patients with de novo AML: EVI1 and MDS1/EVI1 overexpression both predict short remission duration
Authors: Haas Katja , Kundi Michael , Sperr Wolfgang R. , Esterbauer Harald , Ludwig Wolf‐Dieter , Ratei Richard , Koller Elisabeth , Gruener Helga , Sauerland Cristina , Fonatsch Christa , Valent Peter , Wieser Rotraud
Published: January 2008

Rearrangements of chromosome band 3q26.2 lead to overexpression of the EVI1 gene and are associated with a poor prognosis in myeloid malignancies. EVI1 is also overexpressed in some cases without 3q26 rearrangements. To uncover its prognostic significance in this patient group, however, it may be necessary to distinguish among several known 5′‐end variants of its mRNA. According to a recent report, overexpression of the transcript variant EVI1_1d was associated with shortened survival in acute myeloid leukemia (AML), but overexpression of MDS1/EVI1, whose protein product differs structurally and functionally from that of all other known EVI1 5′‐end variants, was not. The aim of the present study was to determine, for the first time, the expression and prognostic significance of all known EVI1 5′‐end variants in AML. Quantitative RT‐PCR was used to measure the expression of EVI1_1a, EVI1_1b, EVI1_1d, EVI1_3L, and MDS1/EVI1 in 266 samples from patients with de novo AML. To correlate expression of the EVI1 5′‐end variants with survival parameters, regression analyses were performed. 41/266 patients (15.4%) overexpressed at least one, but more often several or all, EVI1 transcript type(s). High expression of each of the EVI1 mRNA variants, including MDS1/EVI1, was significantly associated with shortened continuous complete remission in the total patient population as well as in the subgroups of patients with intermediate risk or normal cytogenetics. The present study therefore shows that high levels of each of the known EVI1 mRNA 5′‐end variants represents an adverse prognostic factor in de novo AML without 3q26 rearrangements. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045‐2257/suppmat.© 2008 Wiley‐Liss, Inc.
Controlled delivery of platelet‐rich plasma‐derived growth factors for bone formation
Authors: Lu Helen H. , Vo Jennifer M. , Chin Hsin Sheila , Lin Jeffrey , Cozin Matthew , Tsay Rick , Eisig Sidney , Landesberg Regina
Published: January 2008

Platelet‐rich plasma (PRP) represents an autologous source of growth factors essential for bone regeneration. The clinical efficacy of PRP is, however, unpredictable, and this is likely due to the inefficient and inconsistent delivery of PRP‐derived growth factors. Previous investigations have shown that current methods of PRP preparation result in a premature release of the relevant bone stimulatory factors. As successful bone regeneration requires multiple factors presented in a physiologic temporal and spatial cascade, the objective of this study is to control the bioavailability of PRP‐derived growth factors using a hydrogel carrier system. Specifically, the release of platelet‐derived growth factor, transforming growth factor beta‐1, and insulin‐like growth factor from two types of alginate carriers was compared over time. The effects of the released factors on the growth and alkaline phosphatase (ALP) activity of human osteoblast‐like cells were also evaluated. It was found that factor release profiles varied as function of carrier type, and binding of growth factors to the alginate matrix also modulated their release. The bioactivity of released factors was maintained in vitro and they promoted cell proliferation and ALP activity. These results demonstrate the potential of this autologous multifactor delivery system for controlling the bioavailability of PRP‐derived factors. Future studies will focus on optimizing this system to increase the clinical efficacy of PRP by matching the distribution and temporal sequencing of PRP‐derived factors to the bone healing cascade. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Effects of γ‐irradiation, storage and hydration on osteoinductivity of DBM and DBM/AM composite
Authors: Qiu Qing‐Qing , Connor Jerome
Published: January 2008

This study investigated the effect of γ‐irradiation dose, irradiation temperature, hydration and storage condition on osteoinductivity of demineralized bone matrix (DBM) and demineralized bone matrix/acellular dermal matrix (DBM/AM) composite. DBM and DBM/AM in dry and hydrated form were treated with γ‐irradiation of 15–40 kGy at ambient or low temperature (−40°C ∼ −70°C) and then stored at ambient condition for 6 months. The athymic rat muscle implant model was used to evaluate the osteoinductive potential of the DBM and DBM/AM composites. Histological and alkaline phosphatase (ALPase) activity assessments were carried out at 28 days after implantation to determine the new bone formation and ALPase activity. Both histological and ALPase activity analysis showed that the osteoinductivity of DBM decreased with the increase of γ‐irradiation dose at ambient temperature, whereas no decrease occurred when treated with γ‐irradiation at low temperature. However, the hydrated DBM showed diminishing osteoinductivity after 6‐month storage at ambient condition, whereas the DBM in dry form retained their osteoinductivity after the 6‐months storage. The findings in this study indicate that DBM and DBM/AM composites could retain their osteoinductivity when they are in dry configuration and are irradiated at low temperature (−40°C ∼ −70°C) using the custom‐made cold γ‐irradiation system. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
Bioimaging of dexamethasone and TGF β‐1 and its biological activities of chondrogenic differentiation in hydrogel constructs
Authors: Na Kun , Kim Sungwon , Sun Bo Kyung , Woo Dae Gyun , Yang Han Na , Chung Hyung‐Min , Park Keun‐Hong
Published: January 2008

This study examined the efficacy of poly(NiPAAm‐co‐AAc) as an injectable drug delivery vehicle and a cell therapeutic agent in the form of a supporting matrix for the chondrogenic differentiation of rabbit chondrocytes. The hydrogel constructs, which consisted of embedded cells co‐encapsulating dexamethasone (Dex) and TGF β‐1 or unloaded Dex, were used as controls to determine the effects of Dex and TGF β‐1 on chondrogenic differentiation. The level of Dex and TGF β‐1 released was monitored using a bioimaging method. The amount of Dex released from hydrogel was faster than that of TGF β‐1. TGF β‐1 was present in hydrogel for more than 4 weeks after the injection. The level of the cartilage associated ECM proteins was examined by immunohistochemical staining for collagen type II as well as by Safranin‐O and Alcian blue (GAG) staining. These results highlight the potential of a thermo‐reversible hydrogel mixed with the chondrocytes and differentiation delivery material for applications in neocartilage formation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2008
CMV antibody prevalence and seroincidence in plateletpheresis donors
Authors: Boeke Caroline E. , Pauly Megan E. , Hatch‐Stock Holly , Jackson J. Brooks
Published: January 2008

Objective: To determine the prevalence and seroincidence of CMV seropositivity in plateletpheresis donors of different ages and gender. Methods: CMV antibody serostatus, birthdate, and date of first and most recent donation between the years 1976 and 2006 were retrieved from 222 plateletpheresis donor records at the Johns Hopkins Hospital Donor Center. CMV antibody serostatus was obtained for 183 donors at the most recent donation for which CMV antibody data were available. CMV antibody status and time interval between first and most recent donation were also obtained from 97 repeat plateletpheresis donors who were CMV antibody negative at time of first donation. Results: Overall CMV antibody positivity was 35.5% for 183 donors (mean age = 46.0 years) at time of most recent donation. CMV seropositivity tended to increase with age, being 37.5, 17.9, 37.5, 39.0, and 61.5% for donors aged 20–29 years (n = 8), 30–39 years (n = 39), 40–49 years (n = 64), 50–59 years (n = 59), and 60+ years (n = 13), respectively. Overall CMV seroincidence was 1.6 seroconversions per 100 person years with a rate of 1.4 seroconversions per 100 years for men and 2.3 for women. Conclusion: CMV seroprevalence and seroincidence in this plateletpheresis donor population are relatively low so that a large percentage of donors are likely to be able to provide CMV seronegative platelet components for many years. Our data suggest that targeting groups with lower CMV seroprevalence and seroincidence rates such as young people and possibly men will likely yield the highest percentage of CMV seronegative donors. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Fine mapping and functional activity of the adenosine deaminase origin in murine embryonic fibroblasts
Authors: Sibani Sahar , Rampakakis Emmanouil , Di Paola Domenic , Zannis‐Hadjopoulos Maria
Published: January 2008

DNA replication initiates at origins within the genome. The late‐firing murine adenosine deaminase (mAdA) origin is located within a 2 kb fragment of DNA, making it difficult to examine by realtime technology. In this study, fine mapping of the mAdA region by measuring the abundance of nascent strand DNA identified two origins, mAdA‐1 and mAdA‐C, located 397 bp apart from each other. Both origins conferred autonomous replication to plasmids transfected in murine embryonic fibroblasts (MEFs), and exhibited similar activities in vivo and in vitro. Furthermore, both were able to recruit the DNA replication initiator proteins Cdc6 and Ku in vitro, similar to other bona fide replication origins. When tested in a murine Ku80−/− cell line, both origins exhibited replication activities comparable to those observed in wildtype cells, as did the hypoxanthine‐guanine phosphoribosyltransferase (HPRT) and c‐myc origins. This contrasts with previously published studies using Ku80‐deficient human cells lines and suggests differences in the mechanism of initiation of DNA replication between the murine and human systems. J. Cell. Biochem. 104: 773–784, 2008. © 2008 Wiley‐Liss, Inc.
On substructures of abelian difference sets with classical parameters
Authors: Jennings Kevin
Published: January 2008

We constrain the structure of difference sets with classical parameters in abelian groups. These include the classical Singer 7 and Gordon et al. 4 constructions and also more recent constructions due to Helleseth et al. 5, 6 arising from the study of sequences with ideal autocorrelation properties. A unified overview of the known families is given in 3 and 3. We show here that any abelian difference set with these parameters inherits a very regular intersection property with regard to subgroups. We show in particular that a planar difference set can always be found embedded in an abelian difference set of odd order whose parameters are those of a 5‐dimensional projective geometry. © 2008 Wiley Periodicals, Inc. J Combin Designs 16: 182–190, 2008
Vascular smooth muscle cell polyploidy: An adaptive or maladaptive response?
Authors: McCrann Donald J. , Nguyen Hao G. , Jones Matthew R. , Ravid Katya
Published: January 2008

Polyploidy is a state in which a cell contains multiple copies of its entire genome, while a normal diploid cell contains only two sets of homologous chromosomes. Although widely studied and pervasive in nature, the signals and mechanisms of polyploidization and its accompanying operational consequences are still unclear. This review focuses on relevant questions in deciphering the regulation of polyploidization of vascular smooth muscle cells (VSMC) in mammals and the role of polyploidy in various vascular pathologies, such as hypertension and aging. Additionally, we will explore new investigations in polyploidization of VSMCs involving the rapidly expanding fields of oxidative stress and senescence. J. Cell. Physiol. 215: 588–592, 2008. © 2008 Wiley‐Liss, Inc.
Practical experiences from the development of aqueous two‐phase processes for the recovery of high value biological products
Authors: Benavides Jorge , Rito‐Palomares Marco
Published: January 2008

The development of recovery processes using aqueous two‐phase systems (ATPS) has been limited by the extensive experimental work required to establish the optimal system parameters to ensure selective partitioning of the product of interest. Although using full factorial experiments has been demonstrated to be an effective strategy for the characterization of the partitioning behaviour of biological products in ATPS, this approach is characterized by its costly and time consuming nature. As an alternative, the use of a robotic‐aided strategy has been proposed. However, the need for high cost equipment may limit the generic implementation of this strategy. Based on practical experience using ATPS, practical strategies for the predictive design of primary recovery processes using polymer–salt systems were derived. To evaluate the generic application of the proposed strategies, four experimental models (B‐phycoerythrin, C‐phycocyanin, double layered rotavirus‐like particles and lutein) were selected. The application of these strategies resulted in the development of simplified recovery processes for the selected experimental models. The practical review presented is considered a relevant contribution that will provide general rules to facilitate the establishment of ATPS processes, particularly for new researchers in the field. Copyright © 2007 Society of Chemical Industry
Challenges and trends in bioseparations
Authors: Asenjo Juan A , Andrews Barbara A
Published: January 2008

In this paper the issues and challenges presented 15 years ago for performing efficient separation processes for recombinant proteins are revised and discussed. Competitive advantage in production was seen as not only dependent on innovations in molecular biology and other areas of basic biological sciences but also on innovation of separations and downstream processes. The trend to develop techniques that exploit fundamental physicochemical principles more efficiently was emphasized, including analysis of the physicochemical properties of proteins and its relation to efficiency in bioseparation. 15 years ago the main thrust was also focused on the development of novel techniques. Clearly the challenges faced today, where highly optimized and efficient production processes exist, are dramatically different. The use of mathematical models for optimizing chromatographic separations and simplifying validation of such operations is extremely advantageous. Their use constitutes an example of how the challenges that bioseparations are facing and will be facing within the next few years can be met. Such models should be extended to a larger number of proteins, chromatographic procedures and experimental conditions. Copyright © 2008 Society of Chemical Industry
The use of colloidal gas aphrons as novel downstream processing for the recovery of astaxanthin from cells ofPhaffia rhodozyma
Authors: Dermiki Maria , Gordon Mike H , Jauregi Paula
Published: January 2008

BACKGROUND:There is an increasing interest in obtaining natural products with bioactive properties, using fermentation technology. However, the downstream processing consisting of multiple steps can be complicated, leading to increase in the final cost of the product. Therefore there is a need for integrated, cost‐effective and scalable separation processes.

RESULTS:The present study investigates the use of colloidal gas aphrons (CGA), which are surfactant‐stabilized microbubbles, as a novel method for downstream processing. More particularly, their application for the recovery of astaxanthin from the cells ofPhaffia rhodozymais explored. Research carried out with standard solutions of astaxanthin and CGA generated from the cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) showed that up to 90% recovery can be achieved under optimum conditions, i.e., pH 11 with NaOH 0.2 mol L−1. In the case of the cells' suspension from the fermentation broth, three different approaches were investigated: (a) the conventional integrated approach where CGA were applied directly; (b) CGA were applied to the clarified suspension of cells; and finally (c) thein situapproach, where CGA are generated within the clarified suspension of cells. Interestingly, in the case of the whole suspension (approach a) highest recoveries (78%) were achieved under the same conditions found to be optimal for the standard solutions. In addition, up to 97% recovery of total carotenoids could be achieved from the clarified suspension after pretreatment with NaOH. This pretreatment led to maximum cell disruption as well as optimum conditioning for subsequent CGA separation.

CONCLUSIONS:These results demonstrate the potential of CGA for the recovery of bioactive components from complex feedstock. Copyright © 2008 Society of Chemical Industry
Synthesis and Mechanical Properties of Polypropylene‐based Polymer Hybrids via Controlled Radical Polymerization
Authors: Kaneko Hideyuki , Matsuo Shingo , Kawahara Nobuo , Saito Junji , Matsugi Tomoaki , Kashiwa Norio
Published: January 2008

Isotactic polypropylene‐based graft copolymers linking poly(methyl methacrylate), poly(n‐butyl acrylate) and polystyrene were successfully synthesized by a controlled radical polymerization with isotactic polypropylene (iPP) macroinitiator. The hydroxylated iPP, prepared by propylene/10‐undecen‐1‐ol copolymerization with a metallocene/methyl‐aluminoxane/triisobutylaluminum catalyst system, was treated with 2‐bromoisobutyryl bromide to produce a Br‐group containing iPP (PP‐g‐Br). The resulting PP‐g‐Br could initiate controlled radical polymerization of methyl methacrylate, n‐butyl acrylate and styrene by using a copper catalyst system, leading to a variety of iPP‐based graft copolymers with a different content of the corresponding polar segment. These graft copolymers demonstrated unique mechanical properties dependent upon the kind and content of the grafted polar segment.
Kinetic and Active Centre Studies on the Polymerization of Propylene using MgCl2 Supported Ziegler – Natta Catalysts and 1,3 Diether Donors
Authors: Yaluma Andrew K. , Chadwick John C. , Tait Peter J. T.
Published: January 2008

All polymerization experiments were carried out in a Büchi glass reactor capable of operating at propylene pressures of 1‐7 atmospheres. Two types of MgCl2 supported catalysts with controlled morphology were studied, viz., catalyst systems containing either a 1,3 diether (Catalysts A and D), 9,9‐bis (methoxymethyl) fluorene, or a simple diester (Catalysts B, C and E) such as diisobutylphthalate, used as reference systems. The kinetic behaviours of these catalysts were investigated for propylene polymerization. The 1,3‐diether based systems proved to be excellent catalyst systems for propylene polymerization showing high polymerization activities and stable rate‐time profiles and produced spherical polymer particles. Catalyst pre‐treatment was found to play an important role in controlling the morphology of the final polymer. A tritiated alcohol radio‐quenching technique was used to determine the concentrations active centres: values of 7.5 and 5.1 mol/mol % respectively were obtained for catalysts A and D and 3.5, 2.9 and 2.2 mol/mol % respectively were obtained for catalysts B, C and E. Catalysts A and D showed very high polymerization activities and also higher C0* values. All polymers produced were characterized by SEM, DSC, extraction and molecular weight determinations.
Experimental and Computational Approaches on the Isospecific Role of Monoester‐Type Internal Electron Donor for TiCl4/MgCl2 Ziegler‐Natta Catalysts
Authors: Liu Boping , Cheng Ruihua , Liu Zhen , Qiu Pengyuan , Zhang Shiliang , Taniike Toshiaki , Terano Minoru , Tashino Kunihiko , Fujita Takashi
Published: January 2008

In this work, a combination of experimental and computational approaches on the isospecific role of monoester‐type internal electron donors (ED) such as phenylpropionate (PhP), ethylheptanoate (EH), methylbenzoate (MB), ethylbenzoate (EB) for TiCl4/ED/MgCl2 Ziegler‐Natta catalysts had been performed. The propylene polymerization results revealed that the isospecificity of catalysts increases in the following order: PhP < EH < MB < EB. The subsequent molecular modeling on the electronic properties of the donors and two kinds of cluster model catalysts: TiCl4/ED/MgCl2 and TiCl4/ED/(MgCl2)4 based on density functional theory (DFT) method was carried out. Two kinds of ED coordination on MgCl2 clusters through either O or O within the monoester‐type ED had been disclosed. A perfect correlation between the dipole moment of ED, the coordination bond length of O … Mg, the competitive coordination from O with Mg ion and the isospecificity of the catalysts had been established.
Density Functional Calculations for Electronic and Steric Effects of Ethyl Benzoate on Various Ti Species in MgCl2‐Supported Ziegler‐Natta Catalysts
Authors: Taniike Toshiaki , Terano Minoru
Published: January 2008

Possible coadsorption states of Ti mononuclear species and ethyl benzoate (EB) and their interaction on MgCl2 (110) and (100) surfaces were investigated with periodic density functional calculations in order to obtain the microscopic understanding about how EB affects the steric and electronic natures of the Ti species. EB was unlikely to be attached to the TiCl4 species on both the MgCl2 (110) and (100) surfaces. The coadsorption of EB at Mg2+ ions near the Ti species was as favorable as the separate adsorption, which implied the random placement of these adsorbants in the final catalyst. The charge redistributions upon coadsorption among the Ti species, EB and the support were found to be dependent on the surface structures: the electron density of the Ti speceies was rather decreased by the coadsorption on the (100) surface, while that of the Ti species was enhanced due to the support‐mediated electron transfer from EB on the (110) surface. It was suggested that the presence of EB close to the Ti species should generate donor‐related active sites selectively on the (110) surface.
Supported Zr‐and Hf‐cene Catalysts for Propylene Polymerization
Authors: Novokshonova L. A. , Ushakova T. M. , Lysova M. V. , Kudinova O. I. , Krasheninnikov V. G. , Lyubimtsev A. L.
Published: January 2008

The supported metallocene catalysts were obtained on the layered silicate montmorillonite (MMT), using AlMe3 and AliBu3 for synthesis of alkylaluminoxane directly on a support surface, followed by metallocene supporting. It was shown that the MMT‐H2O/AliBu3 forms with ansa‐Zr‐cenes of C1 and C2‐symmetry the significantly more active supported metal‐alkyl complexes in propene polymerization, than MMT‐H2O/AlMe3. The MMT‐H2O/AliBu3 is the effective activator of the ansa‐Hf‐cenes, in contrast to MAO and MMT‐H2O/AlMe3, giving the high active supported catalysts for synthesis of isotactic and elastic polypropene. The character of influence of metallocene fixation on support on the isotactic pentad [mmmm] content in polymer, compared to homogeneous analogues, depends on the metallocene nature. The introduction of borate Ph3CB(C6F5)4 in the case of both Zr‐cene and Hf‐cene catalysts increases significantly the activity at the reduced ratio of Al/Zr, Hf (100–500 instead of 2000–3000) and stabilizes the catalytic complexes.
Improvement of Structure and Properties of Polypropylene/Poly(ethylene‐co‐propylene) In‐reactor Alloy by Modifying the Cocatalyst
Authors: Dong Qi , Fan Zhiqiang , Fu Zhisheng , Xu Junting
Published: January 2008

Summary: A series of polypropylene/poly(ethylene‐co‐propylene) in‐reactor alloy were synthesized by a TiCl4/MgCl2/SiO2/diester type Ziegler‐Natta catalyst, using triethylaluminium (TEA), triisobutylaluminium (TIBA) or TEA/TIBA mixtures of different molar ratio as cocatalyst. Mechanical properties of the alloy are strongly influenced by the cocatalyst. Toughness‐stiffness balance of the alloy synthesized using a 50/50 TEA/TIBA mixture as cocatalyst is much better than that of the alloy based on pure TEA cocatalyst. Changes in copolymer chain structure and composition distribution are thought to be the main reason for this improvement of properties.
A Flat Model Approach to Ziegler‐Natta Catalysts for Propylene Polymerization and a Preparation Method of Well‐defined Crystallites of MgCl2‐supported Catalysts
Authors: Andoni Adelaida , Chadwick John C. , Niemantsverdriet Hans (J.W.) , Thune Peter C.
Published: January 2008

Summary: An active model for a Ziegler‐Natta propylene polymerization catalyst has been prepared by spin‐coating of a MgCl2/diether donor solution in ethanol on a flat silica wafer, followed by crystal growth by Ostwald ripening to give well‐defined MgCl2 · diether · nEtOH crystallites. The flat model approach facilitates detailed characterization of the catalyst and polymer using surface spectroscopy and microscopy techniques. The growth of the crystallites on the flat silica indicates formation of only 120° edge angles, suggesting the preference for the formation of one particular crystallite face for the MgCl2. Subsequent treatment with TiCl4 generates the catalyst and in propylene polymerization polymer forms on the lateral face of each crystallite.
Ultrahigh Molecular Weight Ethene Copolymers from Metallocene and Ziegler Catalysts
Authors: Hasebe Koichi , Fujiwara Akio , Nozaki Takashi , Miyamoto Koichi
Published: January 2008

In this study, ultrahigh molecular weight polyethene homopolymer and copolymer were successfully produced with the metallocene and the Ziegler catalyst system. In case with the metallocene catalyst system, viscosity average molecular weight of the homopolymer was controlled from 2 million to 10 million. Also, the molecular weight of the copolymer was reached up to 6 million. In case with the Ziegler catalyst system, the molecular weight of the copolymer was reached up to 4 million. The transparency of the copolymer by the Ziegler catalyst, with which the copolymer with better uniformity was produced, could be comparable with that by the metallocene catalyst.
Chromium Catalysts for Butadiene and Norbornene Polymerization
Authors: Ricci Giovanni , Boglia Aldo , Boccia Antonella Caterina , Zetta Lucia
Published: January 2008

A new class of chromium catalysts were obtained by combining bidentate phosphine chromium(II) complexes with methylaluminoxanes. These systems were found to be very active in the polymerization of butadiene giving 1,2 polymers having different tacticity (iso or syndio) depending on the type of phosphine bonded to the chromium atom. Moreover, they were also able to polymerize norbornene, giving crystalline all exo‐enchained vinyl addition polymers, exhibiting a rather unusual structure in the field of olefin stereospecific polymerization, namely diheterotactic structure, characterized by regular sequences of (mr) atactic triads.