bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular and Supramolecular Synthesis with Dibenzofuran‐Containing Systems
Authors: Asakawa Masumi , Ashton Peter R. , Brown Christopher L. , Fyfe Matthew C. T. , Menzer Stephan , Pasini Dario , Scheuer Cecile , Spencer Neil , Stoddart J. Fraser , White Andrew J. P. , Williams David J.
Published: July 2007

The template‐directed syntheses of two new tetracationic cyclophanes, cyclobis(paraquat‐2,8‐dibenzofuran) and cyclobis(paraquat‐3,7‐dibenzofuran), incorporating dibenzofuran subunits has been accomplished. Initially, the cyclophanes were self‐assembled around a macrocyclic polyether template, bis‐p‐phenylene[34]crown‐10 (BPP34C10), to form catenanes: the mechanical bond order of the catenane formed determined the requisite “amacrocyclic” templates for synthesis of the free cyclophane. X‐ray crystallography shows that both of the cyclophanes possess rectangular covalent frameworks. Furthermore, these cyclophanes form self‐assembled tapes in the solid state, since the dibenzofuran moieties have a tendency to associate with each other through crossed ∞–∞ stacks. The dibenzofuran‐containing catenanes also form two‐dimensional supramolecular arrays in the solid state on account of extended ∞–∞ stacking interactions. In addition, the serendipitous discovery of a plerotopic tecton (consisting of a dibenzofuran nucleus covalently linked from the 2‐ and 8‐positions by methylene groups to 4,4′‐pyridylpyridinium (hydrogen bond acceptor) and protonated bipyridinium (hydrogen bond donor) units) has been made. The tecton dimerizes in the solid state to form a supramolecular macrocycle, since its complementary hydrogen bonding sites are oriented in a horseshoelike fashion by the 2,8‐disubstituted dibenzofuran unit. However, this superstructure is not retained in the 1:1 complex of the tecton with BPP34C10: cocrystallization of the tecton with this crown ether opens the macrocyclic two‐component supermolecule to afford a hydrogen‐bonded pseudopolyrotaxane.
Intermetallic s̀ and ∞ Communication in Heterodinuclear μ‐Cyclooctatetraene Complexes
Authors: Bögels Gerdjan , Brussaard Hugo C. , Hagenau Ute , Heck Jürgen , Kopf Jürgen , van der Linden Johannes G. M. , Roelofsen Annie
Published: July 2007

The reaction of [(C5R5)Cr(∞6‐Cot)] (R = H, Me; Cot = cyclooctatetraene) with [(CO)3Fe(∞‐cis‐cyclooctene)2] affords the heterodinuclear complexes [(C5R5)Cr{μ‐∞5(Cr):∞3(Fe)‐Cot}Fe(CO)3] (R = H: 1, R = Me: 2) in quite good yields. One of the CO ligands in 1 and 2 can be easily substituted by a phosphane ligand, PR3 (R = Me, Ph, OEt, F) to obtain [(C5R5)Cr{μ‐∞5(Cr):∞3(Fe)‐Cot}Fe‐(CO)2PR3] (R = H, R = Me: 3a; R = H, R = Ph: 3b; R = Me, R = Me: 4a; R = Me, R = Ph: 4b; R = Me, R = OEt: 4c; R = Me, R = F: 4d). The X‐ray structure determinations of 2, 3a, and 4c showed exclusively synfacial coordination of the two metal ligand moieties, despite the bulky C5Me5 (Cp*) ligand in 2 and 4c. However, the steric demand of Cp* gives rise to structural distortions in 2 and 4c, compared to the Cp‐containing products 1 and 3a, and an elongation of the Cr–Fe distance from 293 pm to 303 and 304 pm, respectively. The heterodinuclear complexes were investigated by cyclic voltammetry and ESR spectroscopy in order to elucidate the role of the permethylation of the cyclopentadienyl ligand and the influence of phosphane ligands with different π‐accepting abilities. The ESR spectroscopic results reveal surprisingly large 31P hyperfine coupling constants (hfcc). These can be explained by a superposition of two different electron spin transfer mechanisms, which include a s̀‐ and a π‐bonding mode between the Cr and Fe centers.
Reaction Paths for the Conversion of Methane to Methanol Catalyzed by FeO+
Authors: Yoshizawa Kazunari , Shiota Yoshihito , Yamabe Tokio
Published: July 2007

We propose possible theoretical reaction paths for the conversion of methane to methanol catalyzed by FeO+. The geometric and electronic structures for the reactant, product, intermediates, and transition states were calculated and analyzed in detail by means of a hybrid Hartree–Fock/density functional method. Sextet and quartet spin states were taken into consideration in the analysis of the reaction paths. The conversion of methane to methanol was shown to proceed through basic concerted hydrogen‐ and methyl‐shift reactions. A fragment molecular orbital analysis for the formation of the reactant complex, OFe+–CH4, which plays an important role in the initial stage of methane activation, was carried out in order to understand the nature of the interesting Fe–C bond. The five‐coordinate methane in the reactant complex was calculated to have a C3v‐type geometry. Each reaction path presented in this paper includes an important insertion species, HO–Fe+–CH3 or H–Fe+–OCH3, and two transition states. Thus, there are several kinds of reaction paths, if the high‐spin sextet and low‐spin quartet states are taken into consideration. A reaction towards the hydroxy intermediate, HO–Fe+–CH3, was found to be more favorable in both the sextet and quartet spin states from the viewpoint of activation energy, and this intermediate is extremely stable. It was found from intrinsic reaction coordinate (IRC) analyses that two basic reactions coexist, namely, hydrogen or methyl migration between the reactant and the methoxy intermediate, H–Fe+–OCH3. This transition state is interesting, because the two transition states resulting from C–H bond cleavage and methyl migration are located in the same region of space on the potential energy surfaces. IRCs are partially shown for the complicated first halves of the total reaction paths.
The impact of new chemotherapeutic and hormone agents on survival in a population‐based cohort of women with metastatic breast cancer
Authors: Chia Stephen K. , Speers Caroline H. , D'yachkova Yulia , Kang Anna , Malfair‐Taylor Suzanne , Barnett Jeff , Coldman Andy , Gelmon Karen A. , O'Reilly Susan E. , Olivotto Ivo A.
Published: July 2007

BACKGROUND.

Over the past decade, a number of new therapeutic agents have become available in the treatment of metastatic breast cancer (MBC). This study characterized the use and assessed the impact on survival of population‐based access to new agents for the treatment of MBC.

METHODS.

The dates of release in British Columbia of 7 new systemic agents for MBC during the 1990s were used to construct 4 time cohorts. All patients with a first diagnosis of distant metastases in each of the time cohorts were identified and characterized, and their survival was compared. Cox proportional regression modeling was used to assess for predictors of survival.

RESULTS.

In total, 2150 patients with a first distant metastases diagnosed during 1 of the 4 cohort intervals were identified. Baseline characteristics between cohorts were similar, except a greater proportion of the later cohorts received adjuvant chemotherapy (P < .001), had positive estrogen receptor status (P = .01), and had a longer median time from initial diagnosis to MBC (P < .001). Survival in Cohort 1 (1991–1992) and Cohort 2 (1994–1995; median, 438 days and 450 days, respectively) was similar. Survival was longer in Cohort 3 (1997–1998; median, 564 days; P = .002) and improved further in Cohort 4 (1999–2001; median, 667 days; P = .05). In multivariate analysis, the later cohorts were associated independently with improved survival (P = .01 and P < .001, respectively).

CONCLUSIONS.

Population‐based access to new therapeutic agents for MBC appeared to be associated with improved survival. To the authors' knowledge, this is the first study to date that demonstrates, from a population‐based perspective, improving survival over the past decade for women with MBC. Cancer 2007. © 2007 American Cancer Society.
Expression of erythropoietin and its receptor in neuroblastomas
Authors: Sartelet Hervé , Fabre Monique , Castaing Marine , Bosq Jacques , Racu Ivan , Lagonotte Emeryc , Scott Véronique , Lecluse Yann , Barette Stephane , Michiels Stefan , Vassal Gilles
Published: July 2007

BACKGROUND.

Children with high‐risk neuroblastomas (NB) potentially may benefit from treatment with recombinant human erythropoietin (Epo). Epo is a stimulator of erythropoiesis, acting through its receptor (EpoR). The objective of the current study was to evaluate expression levels of Epo and EpoR in NB and in normal tissues and their effects on the proliferation of tumor cells.

METHODS.

A tissue microarray study was performed with 101 primary tumors, 39 paired metastases, 56 paired control tissues, and 6 human NB cell lines. Immunohistochemical staining was performed using antibodies against Epo and EpoR. Immunostaining intensity was evaluated by using a semiquantitative score based on the percentage of positive cells. An in vitro analysis of cell proliferation and cell cycle in the presence of recombinant Epo was performed in the 6 cell lines.

RESULTS.

The expression of EpoR was found to be significantly higher in tumors than in paired control tissues (P < .0001) compared with the expression of Epo (P = .06), and the expression of EpoR was significantly higher in lymph node metastases than in paired primary tumors (P = .02) compared with Epo (P = .99). Survival analysis demonstrated that the patients who had tumors with the highest expression of EpoR had a significantly better overall survival (P = .03). In the in vitro study, recombinant Epo did not modify proliferation and cell cycle in the cell lines regardless of the EpoR expression level.

CONCLUSIONS.

Epo and EpoR were expressed in NB but did not modify tumor cell proliferation. The results of the current study suggested that Epo may be used safely for supportive care in children with NB. Cancer 2007. © 2007 American Cancer Society.
Garlic compounds generate reactive oxygen species leading to activation of stress kinases and cysteine proteases for apoptosis in human glioblastoma T98G and U87MG cells
Authors: Das Arabinda , Banik Naren L. , Ray Swapan K.
Published: July 2007

BACKGROUND.

Garlic‐derived organosulfur compounds such as diallyl sulfide (DAS), diallyl disulfide (DADS), and diallyl trisulfide (DATS) provide significant protection against carcinogenesis.

METHODS.

Dose‐dependent cytotoxic effects of the garlic compounds (DAS, DADS, and DATS) were tested in human glioblastoma T98G and U87MG cells. Wright staining and ApopTag assay confirmed induction of apoptosis. Measurements showed that production of reactive oxygen species (ROS) and an increase in intracellular free [Ca2+] promoted apoptosis. Western blot analysis indicated that increased expression and activities of the stress kinases and cysteine proteases caused apoptosis. Use of JC‐1 showed changes in mitochondrial membrane potential (Δψm) for mediation of apoptosis. Use of the specific inhibitors monitored the activation of different kinases and proteases in apoptosis.

RESULTS.

Treatment of glioblastoma cells with garlic compounds triggered production of ROS that induced apoptosis with the phosphorylation of p38 MAPK and activation of the redox‐sensitive JNK1 pathway. Pretreatment of cells with ascorbic acid attenuated ROS production, p38 MAPK phosphorylation, and JNK1 activation. Pretreatment with JNK1 inhibitor I also significantly reduced cell death. Increases in intracellular free [Ca2+], expression of calreticulin, and activation of caspase‐4 indicated involvement of endoplasmic reticulum (ER) stress in apoptosis. Other events in apoptosis included overexpression of Bax, down‐regulation of Bcl‐2 and some BIRC proteins, mitochondrial release of cytochrome c and Smac into the cytosol, and activation of calpain, caspase‐9, and caspase‐3.

CONCLUSIONS.

Garlic compounds induced apoptosis in glioblastoma cells due toproduction of ROS, increase in ER stress, decrease in Δψm, and activation of stress kinases and cysteine proteases. Cancer 2007. © 2007 American Cancer Society.
Effectiveness of sperm banking in adolescents and young adults with cancer
Authors: Neal Michael S. , Nagel Kim , Duckworth JoAnn , Bissessar Haimant , Fischer Marc A. , Portwine Carol , Tozer Richard , Barr Ronald D.
Published: July 2007

BACKGROUND.

Improving success in the treatment of cancer has resulted in an increasing number of survivors. An important quality of life issue among younger survivors is the ability to have a family. Current gonadotoxic treatments for cancer pose a challenge to future fertility. Preservation of fertility after gonadotoxic therapy is an important consideration for these patients. In a regional center, the authors evaluated efficacy and utilization of sperm banking for preservation of male fertility in adolescents and young adults (AYA) with cancer.

METHODS.

A retrospective chart review was conducted to obtain data on clinical features, andrology, and fertility from patients (ages < 30 years) who cryopreserved samples of semen from 1995–2005.

RESULTS.

Of 821 newly diagnosed male AYA cancer patients, aged 14–30 years, only 146 (17.8%) used sperm cryopreservation technology. Patients who used their cryopreserved semen for attempted conception had a 36.4% success rate with intrauterine insemination (IUI) and a 50.0% clinical pregnancy rate with in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

CONCLUSIONS.

Sperm cryopreservation by AYA males with cancer is an efficacious method for preserving future fertility. Awareness and employment of assisted reproductive technologies needs to be implemented by an interdisciplinary team of experts caring for these patients and can result in successful paternity in males after treatment for cancer. Cancer 2007. © 2007 American Cancer Society.
Effects of supportive‐expressive group therapy on survival of patients with metastatic breast cancer
Authors: Spiegel David , Butler Lisa D. , Giese‐Davis Janine , Koopman Cheryl , Miller Elaine , DiMiceli Sue , Classen Catherine C. , Fobair Patricia , Carlson Robert W. , Kraemer Helena C.
Published: July 2007

BACKGROUND.

This study was designed to replicate our earlier finding that intensive group therapy extended survival time of women with metastatic breast cancer. Subsequent findings concerning the question of whether such psychosocial support affects survival have been mixed.

METHODS.

One hundred twenty‐five women with confirmed metastatic (n = 122) or locally recurrent (n = 3) breast cancer were randomly assigned either to the supportive‐expressive group therapy condition (n = 64), where they received educational materials plus weekly supportive‐expressive group therapy, or to the control condition (n = 61), where they received only educational materials for a minimum of 1 year. The treatment, 90 minutes once a week, was designed to build new bonds of social support, encourage expression of emotion, deal with fears of dying and death, help restructure life priorities, improve communication with family members and healthcare professionals, and enhance control of pain and anxiety.

RESULTS.

Overall mortality after 14 years was 86%; median survival time was 32.8 months. No overall statistically significant effect of treatment on survival was found for treatment (median, 30.7 months) compared with control (median, 33.3 months) patients, but there was a statistically significant intervention site‐by‐condition interaction. Exploratory moderator analysis to explain that interaction revealed a significant overall interaction between estrogen‐receptor (ER) status and treatment condition (P= .002) such that among the 25 ER‐negative participants, those randomized to treatment survived longer (median, 29.8 months) than ER‐negative controls (median, 9.3 months), whereas the ER‐positive participants showed no treatment effect.

CONCLUSIONS.

The earlier finding that longer survival was associated with supportive‐expressive group therapy was not replicated. Although it is possible that psychosocial effects on survival are relevant to a small subsample of women who are more refractory to current hormonal treatments, further research is required to investigate subgroup differences. Cancer 2007. © 2007 American Cancer Society.
Quenching and Recoupling of Echo Modulations in NMR Spectroscopy
Authors: Gopalakrishnan Karthik , Aeby Nicolas , Bodenhausen Geoffrey
Published: July 2007

Trains of spin echoes are normally modulated by homonuclear scalar couplings. It has long been known that echo modulations are quenched when the pulse‐repetition rates are much larger than the offsets of the coupling partners, because the spin systems behave as if they consisted of magnetically equivalent spins when the offsets are suppressed. This type of quenching of the echo modulations can occur when the radio‐frequency (RF) pulses are ideal, that is, when they are perfectly homogeneous, properly calibrated to induce rotations through an angle,π, and have an RF amplitude,ω1=−γB1, that is strong compared to the largest offset,ΩS=ω0S−ωRF, with respect to the carrier frequency. Recently, it was discovered that echo modulations can also be quenched when the RF pulses are nonideal, that is, when they are too weak to bring about an ideal rotation of the magnetization of the coupling partners, so that the effective fields associated with the RF pulses are tilted in the rotating frame. This phenomenon typically occurs when the pulse‐repetition rates are much slower than the offset of the coupling partner. Under such conditions, it turns out, however, that for certain offsets, when the phase,ΦS(which arises from a free precession of the magnetization of the coupling partner,S, in the pulse interval, 2τ, and the pulse length,τπ),approaches a multiple of 2π, the echo modulations are restored. However, the frequencies of these echo modulations are not simply determined by the homonuclear scalar coupling,JIS. The Fourier transforms of the echo trains (the so‐called “Jspectra”) reveal surprising multiplet patterns, and the amplitudes of the echo modulations depend on the offsets of the coupling partners. Herein, we present a unified theory, based on an average‐Hamiltonian approach, to describe these effects for two‐spin systems. Experimental evidence of echo modulations in a system of two spins is presented. Experiments with three and more spins, backed up by extensive numerical simulations, will be presented elsewhere.
Dichotic listening deficits in children with dyslexia
Authors: Moncrieff Deborah W. , Black Jeffrey R.
Published: July 2007

Several auditory processing deficits have been reported in children with dyslexia. In order to assess for the presence of a binaural integration type of auditory processing deficit, dichotic listening tests with digits, words and consonant–vowel (CV) pairs were administered to two groups of right‐handed 11‐year‐old children, one group diagnosed with developmental dyslexia and an age‐matched control group. Dyslexic children performed more poorly than controls from their left ears when listening to digits and words and from their right ears when listening to CVs. Direction of ear advantage varied across individuals in both groups when tested with digits and CVs, but ear advantage was stable with words. Several factors that may have contributed to inconsistencies in direction of ear advantage are discussed. When the children were tested in a directed response mode, degree of ear advantage differed significantly between groups with both words and digits. More dyslexic than control children demonstrated clinically significant reductions in dichotic listening performance, but no uniform pattern of deficit emerged. Only the double correct score and the left ear score with CV pairs were predictive of word recognition performance in dyslexic children. Binaural integration deficits are present in some children with dyslexia. Auditory processing disorder assessment may help delineate factors that underlie or are associated with reading impairment in this population. Copyright © 2007 John Wiley & Sons, Ltd.
Baclofen for binge eating: An open‐label trial
Authors: Broft Allegra I. , Spanos Alexia , Corwin Rebecca L. , Mayer Laurel , Steinglass Joanna , Devlin Michael J. , Attia Evelyn , Walsh B. Timothy
Published: July 2007

Objective:

Baclofen is a GABA‐B agonist that may be useful in the treatment of substance use disorders, and also reduces ‘binge‐like’ eating in rodents. We hypothesized that baclofen might be effective in reducing binge eating episodes in binge eating disorder (BED) and bulimia nervosa (BN).

Method:

Seven women with BED (n = 4) or BN (n = 3) took baclofen (60 mg/day) for 10 weeks.

Results:

Six out of seven patients completed the full 10‐week trial. Five out of seven participants (3 BED; 2 BN) demonstrated 50% or greater reduction of frequency of binge eating from beginning to end of the study. Three out of seven participants (2 BED; 1 BN) were free of binge eating at study end. Four out of seven participants elected to continue baclofen at study end. Baclofen was well tolerated by the participants.

Conclusion:

In this open‐label trial, baclofen was associated with decreased binge eating frequency in patients with BED and BN. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
System simulator for structural description and error analysis of multimodal 3D data integration systems
Authors: Sakuragi Futoshi , Nakamoto Masahiko , Sasama Toshihiko , Nakajima Yoshikazu , Sato Yoshinobu , Tamura Shinichi
Published: July 2007

In surgical navigation systems, system error analysis is performed because of the need for correct superposition of three‐dimensional data obtained with three‐dimensional position sensors and different coordinate systems for the images. Lea and colleagues proposed a registration graph for providing a systematic description with a graph of the geometrical position of the system and performing error analysis. However, the registration graph requires the explicit input of errors for each 3D data item. The authors expanded this system to automatically calculate individually occurring errors from system design information through a simulation, and to perform direct error analysis from the system design information. As a result, a user without specialized knowledge of error analysis can automatically perform error analysis by virtually designing a 3D data integration system on a computer. In this paper, the authors constructed a system simulator for modeling point‐to‐point registration and 3D position sensors, performing automatic error calculation with the simulation based thereon, and designing a system easily using a GUI. Furthermore, as a demonstration of the simulator, the simulator was applied to error analysis for a system including point‐to‐point registration and 3D position sensors, and its effectiveness and reliability were confirmed. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(8): 45–59, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20377
Design and Synthesis of a Tag‐Free Chemical Probe for Photoaffinity Labeling
Authors: Mayer Timo , Maier Martin E.
Published: July 2007

The novel aromatic diazirine‐containing benzoic acid 22 was prepared via the diazirine 11 as the key intermediate. After formylation of the aryl ring and cleavage of the methyl ether function of aldehyde 12, the phenolic hydroxy group was converted into the ether 21 terminating in an alkyne function. Oxidation of the aldehyde to the carboxylic acid provided the chemical probe 22 designed for tag‐free photoaffinity labeling. In a proof‐of‐concept study it could be shown that irradiation of the simple ester 23 indeed yields the methanol insertion product 24. A subsequent click reaction with benzyl azide 20 led to the triazole 25. A more complicated example was realized with the esterification of bafilomycin A1 (27) with acid 22. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Characterization of quantum dots using capillary zone electrophoresis
Authors: Pereira Mark , Lai Edward P. C. , Hollebone Bryan
Published: July 2007

Commercially available quantum dots (QDs) were characterized using CE. The CE instruments were laboratory‐built, each being capable of both electrokinetic and hydrodynamic injection. Modes of detection include UV absorption and LIF. The CE‐LIF system was further modified to handle microliter sample volumes during injection. Sodium phosphate (5–25 mM, pH 7.5–11) was found to be a good buffer electrolyte. Sodium mercaptoproprionate CdTe/CdS (ADS620) QDs and carboxylic acid CdSe/ZnS (T2‐Evitag) QDs yielded high separation efficiencies of N = 1.5×106 plates at tM = 10 min and N = 1.0×105 plates at tM = 3.8 min, respectively. Apparently the EDC/sulfo‐NHS bioconjugation chemistry worked well with the neutral T2‐Evitag QDs, but not so well with the negatively charged ADS620 QDs. This preliminary knowledge will serve as a basis for new CE immunoassay studies of QD‐biomolecule conjugates and their immunocomplexes with target analytes.
Transcriptional control of oligodendrogenesis
Authors: Nicolay Danette J. , Doucette J. Ronald , Nazarali Adil J.
Published: July 2007

Oligodendrocytes (OGs) assemble the myelin sheath around axons in the central nervous system. Specification of cells into the OG lineage is largely the result of interplay between bone morphogenetic protein, sonic hedgehog and Notch signaling pathways, which regulate expression of transcription factors (TFs) dictating spatial and temporal aspects of oligodendrogenesis. Many of these TFs and others then direct OG development through to a mature myelinating OG. Here we describe signaling pathways and TFs that are inductive, inhibitory, and/or permissive to OG specification and maturation. We develop a basic transcriptional network and identify similarities and differences between regulation of oligodendrogenesis in the spinal cord and brain. © 2007 Wiley‐Liss, Inc.
Spatial arrangement of microglia in the mouse hippocampus: A stereological study in comparison with astrocytes
Authors: Jinno Shozo , Fleischer Frank , Eckel Stefanie , Schmidt Volker , Kosaka Toshio
Published: July 2007

Microglia are classically considered to be immune cells in the brain, but have now been proven to be involved in neuronal activity as well. Here we stereologically analyzed the spatial arrangement of microglia in the mouse hippocampus. First, we estimated the numerical densities (NDs) of microglia identified by ionized calcium‐binding adaptor molecule 1 (Iba1). Despite that microglia appeared to be evenly distributed throughout the hippocampal area, the NDs demonstrated significant dorsoventral, interregional, and interlaminar differences. Briefly, the NDs in the ventral hippocampus were significantly lower in the CA3 region than in the CA1 region and dentate gyrus, although no interregional differences were detectable in the dorsal hippocampus. Both in the CA1 and CA3 regions, the NDs were significantly higher in the stratum lacunosum‐moleculare than in the remaining layers. Next, we investigated the spatial patterns of distribution of Iba1‐labeled microglia and S100β‐labeled astrocytes. So far as we examined, the somato–somatic contacts were not seen among microglia or among astrocytes, whereas the close apposition between microglia and astrocytes were occasionally detected. The 3D point process analysis showed that the spatial distribution of microglia was significantly repulsive. Because the statistical territory of single microglia was larger than that estimated from process tracing, they are not likely to touch each other with their processes. Astrocytes were distributed slightly repulsively with overlapping areas. The 3D point process analysis also revealed a significant spatial attraction between microglia and astrocytes. The present findings provide a novel anatomical basis for glial research. © 2007 Wiley‐Liss, Inc.
Gastric cancer cells in collagen gel matrix: Three‐dimensional growth and differential expression of adhesion molecules (CD44s, CD54, E‐cadherin)
Authors: Jia Qian , Feng Meifu , Wang Yun , Xue Shaobai
Published: July 2007

To characterize the growth of human gastric cancer cells in collagen gel matrix and adhesive status of the cells in comparison with conventional monolayer cells. Three kinds of human gastric cancer cell lines (BGC823, SGC7901, and MKN28) were cultured alone or co‐cultured with normal human fibroblasts in collagen gel matrix, and their cell cycle, metabolic function, and the expression of adhesive molecules (CD44s, CD54, and E‐cadherin) were analyzed by flow cytometry or other methods. Two of three cell lines (BGC823 and SGC7901) and their co‐cultures showed multilayer growth in collagen gel matrix, and their growth and metabolism rate became slow and the cell adhesion molecules (CAMs) expression was down regulated. Gastric cancer cell alone or with fibroblasts in collagen gel matrix showed distinct growth feature when compared with monolayer cells, which represent two kinds of different experimental models. BGC823 and SGC7901 cells growing in three‐dimension may recur some characteristics of their original solid tumor in vivo with the invasive or metastatic ability. According to different aims, it should pay great care in choice of experimental model to get more reasonable results. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Supported phospholipid bilayers as a platform for neural progenitor cell culture
Authors: Thid D. , Holm K. , Eriksson P.S. , Ekeroth J. , Kasemo B. , Gold J.
Published: July 2007

Supported phospholipid bilayers constitute a biomimetic platform for cell behavior studies and a new approach to the design of cell culture substrates. Phosphocholine bilayers are resistant to cell attachment, but can be functionalized with bioactive molecules to promote specific cell interactions. Here, we explore phosphocholine bilayers, functionalized with the laminin‐derived IKVAV pentamer, as substrates for attachment, growth, and differentiation of neural progenitor cells (AHPs). By varying peptide concentration (0–10%), we discovered a strongly nonlinear relationship between cell attachment and IKVAV concentration, with a threshold of 1% IKVAV required for attachment, and saturation in cell binding at 3% IKVAV. This behavior, together with the 10‐fold reduction in cell attachment when using a jumbled peptide sequence, gives evidence for a specific interaction between IKVAV and its AHP cell‐surface receptor. After 8 days in culture, the peptide‐functionalized bilayers promoted a high degree of cell cluster formation. This is in contrast to the predominant monolayer growth, observed for these cells on the standard laminin coated growth substrates. The peptide‐functionalized bilayer did not induce differentiation levels over those observed for the laminin coated substrates. These results are promising in that peptide‐functionalized bilayers can allow attachment and growth of stem cells without induction of differentiation. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Controlled degradation of multilayered poly(lactide‐co‐glycolide) films using electron beam irradiation
Authors: Chia N.K. , Venkatraman S. S. , Boey F.Y.C. , Cadart S. , Loo J.S.C.
Published: July 2007

The ability to undergo predictable and controlled degradation allows biopolymers to release prescribed dosages of drugs locally over a sustained period. However, the bulk or homogeneous degradation of some of these polymers like poly(L‐lactide) (PLLA) and poly(lactide‐co‐glycolide) (PLGA) work against a better controlled release of the drugs. Inducing the polymers to undergo surface erosion or layer‐by‐layer degradation could provide a better process of controlled drug release from the polymers. This study has demonstrated that surface erosion degradation of PLGA is possible with the use of a multilayer film system, with PPdlLGA [plasticized poly(D,L‐lactide‐co‐glycolide) (PdlLGA)] as the surface layers and poly(L‐lactide‐co‐glycolide) as the center layer. The use of the more hydrophilic PPdlLGA as the surface layer resulted in a faster degradation of the surface layers compared to the center layer, thus giving a surface erosion degradation effect. The rate of surface degradation could also be controlled with electron beam (e‐beam) radiation, where e‐beam irradiation was shown to alter the degradation time and onset of polymer mass loss. It was also shown that the more highly irradiated PPdlLGA surface layers had an earlier onset of mass loss, which resulted in a faster reduction in overall film thickness. The ability to control the rate of film thickness reduction with different radiation dose promises a better controlled release of drugs from this multilayer PLGA film system. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Modification of Ti implant surface for cell proliferation and cell alignment
Authors: Zhao Jia Ming , Tsuru Kanji , Hayakawa Satoshi , Osaka Akiyoshi
Published: July 2007

Surface properties of implants are the keys for ensuring their long‐lasting anchorage to the tissue. This study aims to develop a novel implant surface microstructure with high biocompatibility and ability of guided tissue formation. By a photolithography method, gold (Au) grids (1 × 1 mm2 square lattices, 10 μm in grid‐line width) were deposited on titanium substrates. They were oxidized with H2O2 solution to yield titania (anatase) layer, and the Au grid formed channels due to larger molar volume of anatase than Ti. L‐Cysteine and type I collagen were then immobilized on them to yield the target substrates, CHT–Au–cys–col. Apatite deposited within 3 days when they were soaked in Kokubo's simulated body fluid, regardless of the protein coating, but not on the bottom of the Au channel. Osteoblast‐like MC3T3‐E1 cells were cultured on the CHT–Au–cys–col substrates, showing that (1) the cysteine–collagen coating promoted cell attachment and proliferation, and (2) the Au channels were filled with the cells which were aligned along the channel direction and were connected to the neighboring cells as well as attached to the channel wall with cytoplasmic extensions. The results thus ensured filopodial guidance for the substrates. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Water absorbing and antibacterial properties of N‐isopropyl acrylamide grafted and collagen/chitosan immobilized polypropylene nonwoven fabric and its application on wound healing enhancement
Authors: Wang Chyung‐Chyung , Su Ching‐Hua , Chen Cheng‐Chi
Published: July 2007

A durable sandwich wound dressing system with high liquid absorbing, biocompatibility, and antibacterial properties was designed. Various solution weight ratios of collagen to chitosan were used to immobilize on the polypropylene nonwoven fabric, which were pregrafted with acrylic acid (AA) or N‐isopropyl acrylamide (NIPAAm) to construct a durable sandwich wound dressing membrane with high water absorbing, easy removal, and antibacterial activity. Swelling properties and antibacterial activity of the membranes were measured, and wound healing enhancement by skin full‐thickness excision on animal model was examined. The results indicated that NIPAAm‐grafted and collagen/chitosan‐immobilized polypropylene nonwoven fabric (PP‐NIPAAm‐collagen‐chitosan) showed a better healing effect than AA‐grafted and collagen/chitosan‐immobilized polypropylene nonwoven fabric (PP‐AA‐collagen‐chitosan). The wound treated with PP‐NIPAAm‐collagen‐chitosan demonstrated the excellent remodeling effect in histological examination with respect to the construction of vein, epidermis, and dermis at 21 days after skin injury. The values of water uptake and water diffusion coefficient for PP‐NIPAAm‐collagen‐chitosan were higher than that for PP‐AA‐collagen‐chitosan under a given solution weight ratio of collagen/chitosan. Both PP‐NIPAAm‐collagen‐chitosan and PP‐AA‐collagen‐chitosan demonstrated antibacterial activity. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2008
Anisomycin abrogates repression of protooncogene c‐fos transcription in E1A + cHa‐ras‐transformed cells through activation of MEK/ERK kinase cascade
Authors: Kukushkin Alexander N. , Svetlikova Svetlana B. , Amanzholov Rustam A. , Pospelov Valery A.
Published: July 2007

We have previously shown that transcription of immediate‐early c‐fos protooncogene is becoming strongly repressed in rat embryo fibroblasts transformed by oncogenes E1A and cHa‐ras, so that serum only slightly stimulated c‐fos transcription in these cells in contrast to high level of c‐fos activation in non‐transformed REF52 cells. Here we showed that stress‐inducing agent anisomycin was able to override the c‐fos repression and to induce c‐fos transcription in E1A + ras transformants. In vitro kinase assay data demonstrated that anisomycin increased phosphorylation of transactivation domain of Elk‐1 transcription factor—a key regulator of inducible c‐fos transcription. Importantly, this activation was mediated through up‐regulation of MEK/ERK but not stress‐kinase cascades JNK or p38. The activating effect of anisomycin on c‐fos transcription could be abrogated by a prior treatment with N‐acetyl‐L‐cysteine. This indicates that anisomycin potentiates generation of reactive oxygen species (ROS), which, in turn, can modulate the activity of MAP kinase‐specific phosphatases (MKPs). As anisomycin did not cause acetylation of nucleosome core histones, the present work focuses on the molecular mechanisms mediating the HDAC‐independent induction of IEG c‐fos by anisomycin in E1A + cHa‐ras‐transformed fibroblasts. J. Cell. Biochem. 103: 1005–1012, 2008. © 2007 Wiley‐Liss, Inc.
Tricycloalternarene derivatives produced by an endophyte Alternaria alternata isolated from Maytenus hookeri
Authors: Qiao Li‐Rui , Yuan Lin , Gao Jin‐Ming , Zhao Pei‐Ji , Kang Qian‐Jin , Shen Yue‐Mao
Published: July 2007

A new tricycloalternarene derivative, named tricycloalternarenal (1), together with three known compounds was isolated from the cultures of Alternaria alternata, an endophytic fungus in the leaves of the plant Maytenus hookeri (Celastraceae). Structure of 1 was established as (2E)‐6‐(3,3a,5,6,7,8,9,9a‐octahydro‐5‐hydroxy‐3a‐methyl‐8‐oxo‐cyclo‐penta[b]chromen‐1‐yl)‐2‐methylhept‐2‐enal by spectroscopic methods, including 2D‐NMR experiments. The remaining compounds were determined as tricycloalternarene‐3b (2), alterperylenol (3), and dihydroalterperylenol (4). (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of a Pleurotus ostreatus fruiting body‐specific hydrophobin gene, Po.hyd
Authors: Ma Aimin , Shan Linjun , Wang Nianjiu , Zheng Liesheng , Chen Liguo , Xie Bijun
Published: July 2007

Hydrophobins are a family of small, moderately hydrophobic proteins with eight cysteine residues arranged in a conserved pattern. A full‐length cDNA, designated Po.hyd, corresponding to a hydrophobin gene of Pleurotus ostreatus was obtained in our previous work. The Po.hyd gene contains a 333 bp open reading frame (ORF), which is interrupted by two typical classI introns. There was no consensus signal for a polyA tail detected in the 3′untranslated region. However, an analogous T‐ or TG‐rich motif was observed that probably influence the formation of the mRNA 3′ end. We assign the putative Po.HYD protein to the classI hydrophobins since its sequence arrangement and hydropathy pattern has a high consensus to other known class I hydrophobins. Northern analysis showed that the Po.hyd gene was abundantly expressed throughout the fruiting process (from primordium to mature fruiting body) but silenced during vegetative growth of the mycelium. Southern blot analysis showed Po.hyd to be a single copy gene in the genome of dikaryotic strain likely to locate at the same locus within the two parental genomes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phosphate supply and arsenate toxicity in ectomycorrhizal fungi
Authors: Chen Serena H. , Tibbett Mark
Published: July 2007

Three species of ectomycorrhizal fungi (Hebeloma crustuliniforme, Suillus variegatus and Cenococcum geophilum) were grown in axenic culture amended with range of AsO43– concentration under three different PO43– regimes. The fungi exhibited different growth responses to AsO43– that varied with PO43– concentration. Suillus variegatus showed the greatest sensitivity to AsO43–, with growth almost completely inhibited in the presence of AsO43– under the lower two PO43– treatments. Under the highest PO43– treatment however, growth was enhanced and S. variegatus was able to persist at AsO43– concentrations of up to 4 mM. Hebeloma crustuliniforme also showed high sensitivity to AsO43– especially at low PO43– concentration. The two higher PO43– treatments had an ameliorating effect on AsO43– toxicity in H. crustuliniforme. This demonstrates the ability of PO43– to alleviate AsO43– toxicity. The response from S. variegatus and H. crustuliniforme, both basidiomycetes, was in contrast to the ascomycete C. geophilum. This fungus demonstrated tolerance to AsO43– when grown in culture solution and PO43– did not have an ameliorating effect on AsO43– toxicity in C. geophilum. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A simple model for estimating the maximum intensity of nocturnal urban heat Island
Authors: Montávez Juan Pedro , González‐Rouco Jesús Fidel , Valero Francisco
Published: July 2007

Several studies have tried to determine the empirical relationships between the maximum urban heat island (UHI) intensity and factors such as the city size taking the number of inhabitants as indicator, the geometry of the city (i.e. the H/W ratio), meteorological factors, etc. On the other hand, numerical models have also been formulated to understand the main factors contributing to the formation of UHI.

In this work, a set of empirical equations for determining the maximum of the UHI is presented. The equations have been fitted to the output results of a set of experiments performed by a canyon model (Montávez et al., 2000a), investigating the main factors contributing to the nocturnal UHI. The input parameters are the thermal inertia of rural and urban materials, the H/W ratio and the increase in long‐wave sky radiation due in part to pollution over cities. The results obtained are able to reproduce most of UHI intensity maxima around the world. Copyright © 2007 Royal Meteorological Society
Classification of daily abundant rainfall patterns and associated large‐scale atmospheric circulation types in Southern Portugal
Authors: Fragoso M. , Tildes Gomes P.
Published: July 2007

The aim of this study is to carry out two objective classifications concerning the occurrence of episodes of heavy rainfall in Southern Portugal. The first one seeks to define the main spatial distribution patterns associated with abundant rainfall days in this region. Using a 15‐year (from October 1983 to April 1998) precipitation data base corresponding to 98 sites in Southern Portugal, a sample is established by extracting the precipitation days in which the threshold of 40 mm/24 h was exceeded in three or more stations, yielding a total of 199 days. It is found that the Algarve region is the one where episodes of heavy rainfall are most frequent and which exhibits the strongest torrential character. The highest frequency of days with heavy rain occurs in the fall and in the early part of the winter. Through the combined use of principal component analysis (PCA) and k‐means clustering, four different rainfall patterns are identified, and each one exhibits specific characteristics.

The second classification is obtained using the same computational method (PCA coupled with k‐means) and seeks to define the fundamental large‐scale atmospheric circulation types associated with abundant rainfall in the region, based on sea level pressure (SLP) data. The data was collected from the NCEP/NCAR Reanalysis dataset, taking SLP as the most discriminating variable. Five circulation types are thus obtained, indicating considerable diversity among the large‐scale atmospheric circulation conditions that are conducive to the occurrence of heavy rainstorms in Southern Portugal.

The article concludes by discussing the main links between the two classification schemes, in order to ascertain the influence of the large‐scale atmospheric circulation upon the spatial distribution patterns of heavy precipitation episodes. Copyright © 2007 Royal Meteorological Society
A 10‐year spatial climatology of squall line storms across Oklahoma
Authors: Hocker James E. , Basara Jeffrey B.
Published: July 2007

Severe thunderstorms are an important and relatively common component of the annual weather across the State of Oklahoma. Such weather brings hazardous features such as, large hail, damaging winds, and tornadoes, while also providing beneficial precipitation vital to the state's agricultural and hydrological needs. In any given year, severe weather activity is dictated by seasonal and monthly changes in atmospheric conditions, which frequently determine the type and severity of subsequent storms.

This study focuses on a 10‐year period between 1994 and 2003 to quantify the spatial and temporal characteristics of severe squall line storms across Oklahoma. A squall line is a linearly organized set of storms that has a sharp radar reflectivity gradient at its leading edge typically followed by a less intense stratiform region. Squall line storms are one of the most significant storm modes observed in Oklahoma due to their large aerial extent, long durations, high winds, heavy rains, and hail. For this study, geographic information systems (GIS) were used to store geo‐referenced storm data and spatially analyse storm events across varying timescales. The analysis revealed that squall lines were most predominant across eastern Oklahoma with a decreasing westward gradient. The annual averaged storm track was from the west to east, while the monthly mean squall line tracks were oriented from southwest to northeast from January through April, from west to east during May, from northwest to southeast from June through September, and from southwest to northeast through the end of the year. In addition, high‐resolution analyses of squall line initiation and termination locations revealed important geographical variability in typical storm lifecycle. Copyright © 2007 Royal Meteorological Society
Vertical variations of rain intensity in different rainy periods in and around Bangladesh derived from TRMM observations
Authors: Islam Md. Nazrul , Uyeda Hiroshi
Published: July 2007

In this paper, differences in rain intensity in and around Bangladesh during various rainy periods are described. The data were obtained from tropical rainfall measuring mission (TRMM) ‐2A25, ‐3B42 and ‐3B43. The version 5 (V5) 3B42 daily products overestimated rainfall in pre‐monsoon and post‐monsoon periods but underestimated it in the monsoon period compared with rain‐gauge data. The version 6 (V6) daily products reduced the over‐ and under‐estimation of rainfall. On the basis of the analysed rainfall characteristics in different rainy periods, the 2A25 data was analysed to reveal the vertical variations of rain intensity. Pre‐monsoon rainfall was characterized by convective rain with strong intensity upto high altitudes and high echo tops that usually occurred over land and not over the Bay of Bengal. In contrast, during monsoon, intense rain occurred over the Bay of Bengal and land; however, the existence of strong and high echo tops was less significant than that during the pre‐monsoon period. The radar echo tops and the height of strong rain intensity measured in the post‐monsoon period were lower than those obtained in the monsoon period. Copyright © 2007 Royal Meteorological Society
39-mW annular excitation of ytterbium fiber laser with radial polarization
Authors: Li J-L , Ueda K-I , Shirakawa A , Musha M , Zhong L-X , Zhang Z-M
Published: July 2007

An efficient radial-polarization Yb-fiber laser with an intracavity Brewster axicon is demonstrated. The fraction of ASE at low pumping and parasitical oscillation are minimized by adopting bidirectional pumping and angle-polished fiber end. So far, except for the improvement in polarization purity and cylindrical symmetry of output beam, 39-mW output power is obtained at 460-mW launched pump power with 13.8% slope efficiency. And also a new type of low-V-parameter multi-mode gain fiber with doughnut concentration distribution of active ions in fiber core profile is predicted to be promising in improving the laser performance further.