bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterogeneity of aldehyde dehydrogenase expression in lung cancer cell lines is revealed by Aldefluor flow cytometry‐based assay
Authors: Moreb Jan S. , Zucali James R. , Ostmark Blanca , Benson Neal A.
Published: November 2006

Background:

We have been interested in studying the roles of two aldehyde dehydrogenases in the biology of lung cancer. In this study, we seek to apply Aldefluor flow cytometry‐based assay for the measurement of aldehyde dehydrogenase (ALDH) activity in lung cancer cell lines, which may become a new tool that will facilitate our continued research in this field.

Experimental Design:

Several established lung cancer cell lines were used, including A549 cell line expressing siRNA against aldehyde dehydrogenase class‐1A1 (ALDH1A1). Western blot analysis, spectrophotometry assay, and Aldefluor staining were used to measure protein or enzyme activity in these cell lines. For the purpose of measurement of ALDH activity by Aldefluor in cells with known high ALDH levels, cells were mixed 1:10 with immortalized lung epithelial cell line (Beas‐2B), which is known to lack ALDH activity. To delineate dead cells, double staining using Aldefluor and propidium iodide (PI) was done. Double staining was also used to detect changes in ALDH activity in two different cell lines after treatment with 4‐hydroperoxycyclophosphamide (4‐HC).

Results:

Our results show a very good correlation between Aldefluor, Western blot, and spectrophotometry assays. Mixing experiments with Beas‐2B cells allowed accurate assessment of ALDH activity in A549 cells at baseline and after siRNA expression, thus establishing an approach that facilitates the measurement of very high ALDH using the Aldefluor assay. Aldefluor staining was able to detect heterogeneity in ALDH expression among as well as within the same cell lines and better assess viability after 4‐HC treatment when combined with PI.

Conclusions:

Aldefluor assay can be adapted successfully to measure ALDH activity in lung cancer cells and may have the advantage of providing real time changes in ALDH activity in viable cells treated with siRNA or chemotherapy. © 2006 International Society for Analytical Cytology
Therapeutic applications of incretin mimetics for metabolic diseases: preclinical studies
Authors: Mack Christine , Laugero Kevin , Liu Que , Jodka Carolyn , Young Andrew , Parkes David
Published: November 2006

Exenatide (exendin‐4) is an incretin mimetic peptide that shares several glucoregulatory actions with the endogenous incretin GLP‐1. In addition to its actions on glucose control, exenatide produces effects to reduce food intake and body weight in all species studied. GLP‐1 and exenatide have also been shown to modulate cardiovascular function in both animal and human studies. This overview examines the metabolic effects of exenatide beyond its antidiabetic actions, and will focus on studies with respect to obesity, hypertension, and cardiac dysfunction in preclinical models of diet‐induced obesity, metabolic syndrome, and chronic heart failure. Drug Dev. Res. 67:553–558, 2006.© 2006 Wiley‐Liss, Inc.
Buccal delivery of insulin: the time is now
Authors: Bernstein Gerald
Published: November 2006

The burgeoning numbers of individuals with diabetes mellitus and prediabetes, in particular Type 2 including large numbers of children, open up not only the classic risks for microvascular disease but the earlier and incapacitating risk for macrovascular disease. Oral hypoglycemic agents and insulin sensitizers have not been adequate to control postprandial glucose. Prandial insulin is most desirable but resistance to injections limits its use. This has led to a battery of needle‐free insulin delivery systems. Buccal delivery stands out as being safe, simple, fast, flexible, and familiar to patient and physician alike. Drug Dev. Res. 67:597–599, 2006. © 2006 Wiley‐Liss, Inc.
Our children and the metabolic syndrome
Authors: Desmangles Jean‐Claude
Published: November 2006

The metabolic syndrome is a cluster of metabolic disturbances that result in an increased risk of type 2 diabetes and cardiovascular disease in adults. Despite the lack of a uniform definition of the syndrome for children, several studies have reported an overall prevalence of 3 to 4% among children. Among obese adolescents, the prevalence can be as high as 30 to 50%. Besides insulin resistance and obesity, the intrauterine environment and genetic factors also seem to play a role in the pathogenesis of the syndrome in children. In view of the current obesity epidemic and since an increasing amount of evidence shows that obesity during adolescence is significantly associated with insulin resistance, abnormal serum lipid levels, and elevated blood pressure during adulthood, there is a great need for a clear definition, for the development of screening guidelines, and for appropriate prevention and treatment strategies for the metabolic syndrome in the pediatric population. Drug Dev. Res. 67:602–606, 2006. © 2006 Wiley‐Liss, Inc.
Male hypogonadism and the metabolic syndrome: lessons from clinical studies
Authors: Rodzvilla John P.
Published: November 2006

The symptoms of male hypogonadism can be subtle. The diagnosis must be based on a high degree of suspicion coupled with the finding of low total testosterone, low free testosterone, or low bioavailable testosterone. Appropriate therapy of low testosterone results in improvement of signs and symptoms. The improvements directly related to metabolic syndrome (MetS) are: increased muscle mass, decreased fat mass, and decreased insulin resistance. The correlation of low testosterone with MetS has recently gained impetus with evidence revealing a correlation of low testosterone levels and low levels of sex hormone binding globulin (SHBG) serving as predictors of the development of MetS and diabetes mellitus type 2. The treatment of hypogonadism in males may be accomplished by several methods of testosterone replacement or the stimulation of testosterone production. Given the association of low SHBG and low T levels with MetS, and the potentially positive effects on MetS and diabetes type 2 with treatment of male hypogonadism, further studies are warranted to evaluate hypogonadal treatment effect on MetS, diabetes type 2, and cardiovascular disease. Drug Dev. Res. 67:612–615, 2006. © 2006 Wiley‐Liss, Inc.
Economic aspects of diabetic foot care in a multidisciplinary setting: a review
Authors: Matricali Giovanni A. , Dereymaeker Greta , Muls Erik , Flour Maria , Mathieu Chantal
Published: November 2006

Background

To evaluate the economic aspects of diabetic foot care in a multidisciplinary setting.

Method

A review of the English language literature, published from 1966 to November 2005.

Results

The results of available studies on the cost‐of‐illness of diabetic foot problems are difficult to compare. Nevertheless trends concerning excess of costs, protraction in time of costs, positive correlation to severity of ulcer and/or peripheral vascular disease, contribution of in‐hospital stay and length of stay, and the patient's own contribution to total costs, are obvious. Only a few cost‐effectiveness and cost‐utility studies are available. Most use a Markov based model to predict outcome and show an acceptable result on long‐term.

Conclusions

Diabetic foot problems are frequent and are associated with high costs. A multidisciplinary approach to diabetic foot problems has proved to be cost saving with regard to cost of treatment itself. Nevertheless, it remained unclear if these savings could offset the overall costs involved in implementing this kind of approach. The few studies that address this issue specifically all show an acceptable cost‐effectiveness, but often the profit will be evident after some years only, because long‐term costs are involved. Based on these data, policymakers should foresee sufficient reimbursement for preventive and early curative measures, and not only for ‘salvage manoeuvres’. Copyright © 2007 John Wiley & Sons, Ltd.
Crim1KST264/KST264 mice display a disruption of the Crim1 gene resulting in perinatal lethality with defects in multiple organ systems
Authors: Pennisi David J. , Wilkinson Lorine , Kolle Gabriel , Sohaskey Michael L. , Gillinder Kevin , Piper Michael J. , McAvoy John W. , Lovicu Frank J. , Little Melissa H.
Published: November 2006

Crim1 is a transmembrane protein, containing six vWF‐C type cysteine‐rich repeats, that tethers growth factors to the cell surface. A mouse line, KST264, generated in a LacZ insertion mutagenesis gene‐trap screen, was examined to elucidate Crim1 function in development. We showed that Crim1KST264/KST264 mice were not null for Crim1 due to the production of a shortened protein isoform. These mice are likely to represent an effective hypomorph or a dominant‐negative for Crim1. Transgene expression recapitulated known Crim1 expression in lens, brain, and limb, but also revealed expression in the smooth muscle cells of the developing heart and renal vasculature, developing cartilage, mature ovary and detrusor of the bladder. Transgene expression was also observed in glomerular epithelial cells, podocytes, mesangial cells, and urothelium in the kidney. Crim1KST264/KST264 mice displayed perinatal lethality, syndactyly, eye, and kidney abnormalities. The severe and complex phenotype observed in Crim1KST264/KST264 mice highlights the importance of Crim1 in numerous aspects of organogenesis. Developmental Dynamics 236:502–511, 2007. © 2006 Wiley‐Liss, Inc.
Estimating scale of peer‐to‐peer file sharing applications using multilayer partial measurement
Authors: Kamei Satoshi , Uchida Masato , Mori Tatsuya , Takahashi Yutaka
Published: November 2006

Autonomous distributed systems comprising an overlay network on the Internet are proliferating as a new technology responsible for the next‐generation Web. Due to the properties of such a large‐scale system, it is difficult to measure the characteristics of the entire system without modifying the internal protocol of the applications. In this paper, by using a measurement method applicable to P2P applications and measured results obtained by applying this measurement method in part, a general‐purpose method for estimating the size and behavior of the entire P2P network is proposed. Further, the present method is applied to a real P2P network and its effectiveness is presented by a specific example. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(3): 54–63, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20318
Stochastic node placement improving fault tolerance in wireless sensor networks
Authors: Ishizuka Mika , Aida Masaki
Published: November 2006

One of the most important issues in wireless sensor networks is to develop the technology for improved fault tolerance, since sensor nodes are prone to failure (for mechanical reasons, for example) and have limited energy storage. The strategy for determining the positions in which sensor nodes are placed is very important, because it affects the likelihood that a target will be within the sensing range of a node, and that there will be a communication path from that node back to the base station. We have considered that when many sensor nodes are to be placed in a wide area, an effective approach is stochastic node placement, whereby sensors may be scattered in a controlled manner, such that their approximate positions are characterized by a probability density function. Then, as the first step of our research, we have proposed stochastic node placements in which the degrees of the nodes follow a power‐law distribution (“power‐law placement”). Through simulation studies, we have shown that power‐law placement, with well‐tuned parameters, shows a higher tolerance against random failures and failure through battery exhaustion than general stochastic node placement. However, this can be difficult to implement. As the second step of our research, this paper proposes an alternative method of stochastic node placement that has as high a fault tolerance as power‐law placement and can be achieved with a reasonable degree of complexity. To this end, we first investigate the requirements necessary for other types of stochastic node placement to exhibit as high a fault tolerance as power‐law placement. Next, we propose ways of achieving stochastic node placement that meets these requirements. Our proposal has theoretical basis that any stochastic node placement can be achieved by scattering sensor nodes many times from the air in a number of appropriately controlled operations. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(3): 42–53, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20319
Model policies for land use and the environment: towards a critical typology?
Authors: Peel D. , Lloyd M. G.
Published: November 2006

This article considers contemporary debates in Scotland that are concerned with the design and implementation of land use development plan ‘policies that work’. The interest in developing a resource bank of model policy texts is illustrative of the wider agenda to modernize the public sector and to secure efficiency gains in public policy making. On the one hand, this is presented as strengthening policy makers' ability to achieve stated policy outcomes, and to enforce particular policy objectives in the public interest. On the other hand, it is argued that a more uniform and consistent policy context across Scotland would offer a more certain operating environment for developers and users of the planning service. The discussion considers the diversity of land use planning topics identified as potentially appropriate for formulation as a model policy, and proposes a typology for critically interrogating their suitability in practice. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment.
Prolonged exposure of dendritic cells to maturation stimuli favors the induction of type‐2 cytotoxic T lymphocytes
Authors: Boni Andrea , Iezzi Giandomenica , Degl'Innocenti Elena , Grioni Matteo , Jachetti Elena , Camporeale Annalisa , Bellone Matteo
Published: November 2006

Dendritic cell (DC) maturation influences the priming and polarization of T lymphocytes. We recently found that early activated DC (i.e. DC exposed to pro‐maturation stimuli for 8 h) were more prone to prime in vivo a type‐1 cytotoxic T cell (Tc1) response than DC exposed to pro‐maturation stimuli for 48 h (48h‐DC). We investigated whether 48h‐DC, conversely, allowed the induction of Tc2 cells. Antigen‐pulsed mouse bone‐marrow‐derived DC at any maturation stage, in the presence of exogenous IL‐12, skewed in vitro naive CD8+ T cells towards Tc1 cells, but 48h‐DC most potently, in the presence of exogenous IL‐4, favored the induction of Tc2 cells. In vivo, full maturation of DC promoted expansion of Tc2 and fall of Tc1 cells. Tc2 cells maintained a high cytolytic activity and produced significant amounts of IL‐4, IL‐5, IL‐10 and TGF‐β. Our results indicate that polarization of naive CD8+ T cells to Tc2 cells is dependent on the amount of time DC have been exposed to maturation stimuli, and might be favored in late and/or chronic phases of an immune response.
Structure and duration of contact between dendritic cells and T cells are controlled by T cell activation state
Authors: Rothoeft Tobias , Balkow Sandra , Krummen Mathias , Beissert Stefan , Varga Georg , Loser Karin , Oberbanscheidt Pia , van den Boom Frank , Grabbe Stephan
Published: November 2006

The adaptive immune response is initiated when naive T cells interact with dendritic cells (DC). However, the physicodynamics as well as the molecules that constitute the contact plane (immunological synapse) between DC and T cells are not well understood. We show here that for the formation of stable conjugates, T cells need to be preactivated by DC in a CD80/86‐ and antigen dose‐dependent manner. When activated, T cells induce cytoskeletal reorganization within DC via CD40‐CD40L signaling. Polarization of the actin and fascin cytoskeleton in DC is associated with sustained DC‐T cell contacts, strong T cell proliferation and a Th1 response. Organized contact planes with clearly separated patches containing TCR or CD11a are also formed. Thus, DC‐T cell interactions take place in a sequential, interdependent fashion: first, DC “license” naive T cells to engage DC in an antigen dose‐ and CD80/86‐dependent fashion. Then, these preactivated T cells induce cytoskeletal reorientation in DC, resulting in sustained DC‐T cell contacts and subsequent T cell activation. These results demonstrate that T cells control the mode of interaction based on information gathered from DC.
Transient Notch signaling induces NK cell potential in Pax5‐deficient pro‐B cells
Authors: Carotta Sebastian , Brady Jason , Wu Li , Nutt Stephen L.
Published: November 2006

Unlike early B/T cell development, NK cell lineage commitment is not well understood, with a major limitation being the lack of a robust culture system to assay NK cell progenitors. Here we have exploited the multi‐lineage potential of Pax5–/– pro‐B cells to establish an effective system to direct differentiation of progenitors into the NK cell lineage. Cultivation of Pax5–/– pro‐B cells on OP9 cells expressing the Notch ligand Delta‐Like1 (OP9‐DL1) in the presence of IL‐7 efficiently induced T and NK cell potential. For NK cells, Notch was only transiently required, as prolonged signaling decreased NK and increased T cell development. Pure NK cell populations could be obtained by the culture of these Notch signal‐experienced cells onto OP9 stroma and IL‐15. A similar transient exposure to Notch was also compatible with the differentiation of NK cells from hematopoietic progenitors, while sustained Notch signaling impaired NK cell generation. Pax5–/– pro‐B cell‐derived NK cells were cytotoxic, secreted cytokines and expressed all the expected NK cell‐specific surface markers examined except the Ly49 family, a phenotype similar to fetal NK cells. These data indicate that Notch signaling induces T/NK cell differentiation in Pax5–/– pro‐B cells that is strikingly similar to early thymopoiesis.
Involvement of GATA3 in Protein Kinase C θ‐induced Th2 cytokine expression
Authors: Stevens Lisa , Htut Tin M. , White Della , Li Xiang , Hanidu Adedayo , Stearns Carol , Labadia Mark E. , Li Jun , Brown Maryanne , Yang Jianfei
Published: November 2006

Protein kinase C θ (PKCθ) is essential for T cell activation, as it is required for the activation of NF‐κB and expression of IL‐2. PKCθ has also been shown to affect NFAT activation and Th2 differentiation. To better understand the role of PKCθ in the regulation of T helper cells, we used PKCθ‐deficient DO11.10 transgenic T cells to study its rolein vitro. DO11.10 Th1 cells deficient in PKCθ produced significantly less TNF‐α and IL‐2. The expression of Th2 cytokines, including IL‐4, IL‐5, IL‐10, IL‐13 and IL‐24 was significantly reduced in PKCθ‐deficient T cells. Moreover, the expression of the Th2 transcription factor, GATA3, was significantly reduced in PKCθ‐deficient T cells. Overexpression of GATA3 by retroviral infection in PKCθ‐deficient T cells resulted in increased expansion of IL‐4‐producing T cells and higher IL‐4 production than that of wild type Th2 cells. IL‐5, IL‐10, IL‐13 and IL‐24 expressions were also rescued by GATA3 overexpression. Our observations suggest that PKCθ regulates Th2 cytokine expressionviaGATA3.
Genomic suppression of murine B29/Ig‐β promoter‐driven transgenes
Authors: Vettermann Christian , Lutz Johannes , Selg Manuel , Bösl Michael , Jäck Hans‐Martin
Published: November 2006

Immunoglobulin β (Ig‐β) is a critical signal transducer of precursor B cell and B cell receptors. B29, the gene coding for Ig‐β, is switched on in progenitor B cells and expressed until the terminal stage of antibody‐producing plasma cells. Although several cis‐acting elements and transcription factors required for B29 expression have been characterized in cell lines, the in vivo significance of individual motifs located in the 1.2‐kb promoter region remained unclear. To address whether this region drives B lineage‐specific expression in mice as efficiently as in transfected cell lines, we established transgenic animals carrying the B29 promoter fused to either enhanced green fluorescent protein (EGFP) or the precursor B cell receptor component λ5. Surprisingly, only minimal levels of B29‐derived transcripts were produced in B lymphoid tissues of several independent transgenic lines, and the respective proteins were below the detection limit. In addition, transgenic transcripts were found in testis, kidney and brain. Hence, the 1.2‐kb‐sized B29 promoter does not define a strong, B lineage‐restricted expression unit when randomly integrated into the genome and passed through the murine germ line. Therefore, yet unidentified genomic locus control elements are required to efficiently drive B29 expression in B lymphocytes.
First Allylpalladium Systems Containing Chiral Imidazolylpyridine Ligands – Structural Studies and Catalytic Behaviour
Authors: Bastero Amaia , Bella Antonio F. , Fernández Fernando , Jansat Susanna , Claver Carmen , Gómez Montserrat , Muller Guillermo , Ruiz Aurora , Font‐Bardía Mercè , Solans Xavier
Published: November 2006

Palladium/chiral imidazolylpyridine systems were tested in allylic alkylation of rac‐3‐acetoxy‐1,3‐diphenyl‐1‐propene (rac‐I) and 3‐acetoxy‐1‐phenyl‐1‐propene (II), paying particular attention to the influence of the amine nitrogen hybridisation on their catalytic behaviour. Allylpalladium complexes 9–11 containing optically pure imidazolines were synthesised and fully characterised both in solution (NMR) and the solid state (single‐crystal X‐ray diffraction). NMR studies showed four species in solution for complex 9 containing the unsymmetrical 1‐phenylallyl group, while for 10 and 11, involving the symmetrical 1,3‐diphenylallyl moiety, two species, endo and exo, were identified. In the solid state, only endo isomers crystallised for each complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of Cp* Iridium and Rhodium Complexes Containing Bidentate sp2‐N‐Donor Ligands and Counter‐Anions [Cp*MCl3]–
Authors: Kennedy Danielle F. , Messerle Barbara A. , Smith Matthew K.
Published: November 2006

Complexes of the type [Cp*MCl(N–N)][X] (M = Rh and Ir) have been synthesised, where N–N is a series of bidentate ligands with sp2 N‐donors: bis(pyrazol‐1‐yl)methane (bpm), bis(1‐methylimidazol‐2‐yl)methane (bim), bis(3,5‐dimethylpyrazol‐1‐yl)methane (dmbpm), bis(1‐methylimidazol‐2‐yl) ketone (bik), bis(2,4,6‐trimethylphenylimino)acenapthene (mesBIAN), 2,4,6‐trimethylphenylimino‐(1‐methyl‐2‐imidazolyl)methane (mesim–mim), and X = Cl–, BF4– and the unusual anion [Cp*MCl3]–. All of these complexes were synthesised by treatment of [Cp*MCl2]2 with 2 equivalents of ligand and were isolated as air stable solids. The solid‐state structures of [Cp*MCl(bpm)][Cp*MCl3] (M = Rh and Ir) and [Cp*IrCl(bim)][Cp*IrCl3] have been determined by single‐crystal X‐ray diffraction analysis. All of the structures of the bimetallic species displayed a “piano stool” configuration about the both the anionic and cationic metal centre. The solid‐state structures of the monometallic iridium species [Cp*IrCl(N–N)][BF4], where N–N = bim, mesBIAN, and mesim‐mim, were also determined using single‐crystal X‐ray diffraction analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis and Transition Metal Complexes of Novel N,N,O Scorpionate Ligands Suitable for Solid Phase Immobilisation
Authors: Hübner Eike , Haas Thomas , Burzlaff Nicolai
Published: November 2006

Introduction of an allyl or a hydroxymethyl group to bis(3,5‐dimethylpyrazol‐1‐yl)acetic acid (1) at the bridging carbon atom leads to the new tripodal N,N,O ligands 2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)pent‐4‐enoic acid (Hbdmpzpen) (2) and 2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)‐3‐hydroxypropionic acid (Hbdmpzhp) (3). These ligands exhibit similar chemical behaviour to that of 1, but they have the additional possibility to be immobilised to a solid phase. Esterification of the hydroxymethyl linker of 3 yields 2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)‐3‐acetatopropionic acid (Hbdmpzap) (4). The molecular structures of 2, 3 and 4 all exhibit intramolecular hydrogen bridges. Introduction of a hydroxymethyl group to methyl bis(3,5‐dimethylpyrazol‐1‐yl)acetate (5) yields methyl2,2‐bis(3,5‐dimethylpyrazol‐1‐yl)‐3‐hydroxypropionate(Mebdmpzhp) (6), which can be immobilised on Merrifield polymer to yield modified resin P‐6. To investigate the reactivity of these new ligands, manganese and rhenium complexes of 2, 3 and 4 have been studied. The molecular structures of the two manganese complexes [Mn(bdmpzpen)(CO)3] (7) and [Mn(bdmpzap)(CO)3] (8) have been confirmed by single‐crystal X‐ray structure determination. Saponification of polymer resin P‐6 and subsequent reaction with [ReBr(CO)5] yields rhenium tricarbonyl complexes anchored on Merrifield polymer (P‐Re). Solid phase immobilisation of the [Mn(bdmpzpen)(CO)3] (7) and [Re(bdmpzpen)(CO)3] (9) complexes on 3‐mercaptopropyl functionalised silica is initialised by AIBN. The tripodal coordination of manganese and rhenium in these functionalised Merrifield resins (P‐Re) and silica (S‐Mn, S‐Re) is proven by a single A1 and two E signals in the IR spectra that are typical for unsymmetrical “piano stool” type carbonyl complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Reducing intra‐sample variability of muscle lipid analysis
Authors: Zhou Lianzhen , Guo ZengKui
Published: November 2006

Intra‐sample variability of intramyocellular triacylglycerols (imcTG) in skeletal muscle has been examined using two different tissue processing sequences assisted by tracer and solvent extraction techniques. Aliquoting after homogenization of muscle biopsies significantly reduced intra‐sample variability compared to the aliquoting before homogenization approach. The results suggested that skeletal muscle samples be homogenized before aliquoting, if necessary, in order to reduce variability in imcTG measurements. Intramyocellular non‐esterified fatty acids have a lower variability than triacylglycerols.
The Synthesis of Dendritic β‐Diketonato Ligands and Their Europium Complexes
Authors: Li Bao‐Lin , Liu Zi‐Tong , Deng Guo‐Jun , Fan Qing‐Hua
Published: November 2006

Two kinds of dendritic β‐diketonato ligands (1a,1b and 2a–2c) which contain a dibenzoylmethane (dbm) core and poly(aryl ether) dendron, have been synthesized by a convergent strategy. The attachment point of the dendron to dbm is found to play an important role in the preparation of europium(III) complexes. Reaction of the β‐diketonato ligands 2a–2c, which bear a dendron substituted on the phenyl group of dbm, with EuCl3·6H2O gives the first‐ to third‐generation dendritic europium(III) complexes in good yields, while europium(III) complexes could not be formed with β‐diketonato ligands 1a and 1b, which have dendrons attached to the 2‐position of dbm. The resulting dendritic europium(III) complexes were characterized by elemental analysis and MALDI‐TOF mass spectrometry, and further confirmed by luminescence measurements. Incorporation of 1,10‐phenanthroline as the second ligand in these dendritic (β‐diketonato)europium(III) complexes gives new dendritic europium(III) complexes with enhanced luminescence intensity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Smaragdyrin–Azobenzene Conjugates: Syntheses, Structure, and Spectral and Electrochemical Properties
Authors: Gokulnath Sabapathi , Prabhuraja Viswanathan , Sankar Jeyaraman , Chandrashekar Tavarekere K.
Published: November 2006

The syntheses, characterization, and spectral properties of smaragdyrin–azobenzene conjugates are reported. Our synthetic strategy involves linking the azobenzene group in one of the precursors to a dipyrromethane subunit, which was achieved by reaction of azobenzenecarbaldehyde with pyrrole under TFA catalysis. A [3+2] acid‐catalyzed oxidative coupling of this precursor with the tripyrrane moiety gave the expected smaragdyrin–azobenzene conjugates. The azobenzene is in the (E) conformation both in the precursor and in the smaragdyrin conjugates, as revealed by its single‐crystal X‐ray structure. Electronic absorption and emission spectral studies reveal the presence of a moderate electronic interaction between the azobenzene and smaragdyrin π‐systems. Irradiation experiments at 360 nm reveal the presence of a reversible (E)/(Z) transformation of the azobenzene moiety in the precursors 3b and 4b. However, in the smaragdyrin conjugates the formation of the (Z) conformer leads to the decomposition of the macrocycle upon prolonged irradiation. Excitation at the azobenzene absorption results in the appearance of the emission band of smaragdyrin, thereby suggesting an energy transfer. The electrochemical data reveal that ring oxidations of the smaragdyrin macrocycle become harder upon azobenzene introduction, which suggests the electron‐withdrawing nature of the azobenzene in these conjugates. A significant shortening of the N–N bond (0.067 Å) and elongation of the C–N bonds (0.055 and 0.069 Å) in 7a relative to the azobenzene–dipyrromethane precursor 4a clearly reveal a rearrangement of the electronic π‐delocalization pathway in the smaragdyrin–azobenzene conjugates. RhI binds to one amino and one imino nitrogen atom in the smaragdyrin cavity to form a 1:1 complex. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Absolute Configurations of Globosuxanthone A and Secondary Metabolites from Microdiplodia sp. – A Novel Solid‐State CD/TDDFT Approach
Authors: Hussain Hidayat , Krohn Karsten , Floerke Ulrich , Schulz Barbara , Draeger Siegfried , Pescitelli Gennaro , Antus Sándor , Kurtán Tibor
Published: November 2006

The absolute configuration of a potent new antitumor dihydroxanthenone, globosuxanthone A (1), active against human solid tumor cell lines and isolated by Gunatilaka et al. from Chaetomium globosum Ames1 and in this study from the endophytic fungus Microdiplodia sp., was established by a new methodology. In this new approach, the Cartesian coordinates of the X‐ray data serve as input geometry for quantum mechanical calculation of the theoretical CD spectrum. Comparison with the solid‐state CD spectrum gives a very good match, since the calculated and the experimentally acquired data are derived from the very same single conformation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Regeneration of spent bleaching earth by lye‐extraction
Authors: Chang James I. , Tai Hua‐Shan , Huang Teng‐Hsiang
Published: November 2006

Lye extraction was investigated for regenerating a spent bleaching earth (SBE) generated after the discoloration of crude edible oils. Bivariate regression and response surface methodology were applied to find the optimal ratio of the liquid caustic soda to SBE and the retention time at the boiling temperature. Experimental results showed that the oil content in SBE could be reduced to less than 1% by boiling SBE in an aqueous solution of 1% caustic soda for more than 20 min. The deoiled SBE could be mixed in the soy meal for animal feed. A preliminary financial analysis showed that the investment for a hypothetical 10‐ton/day processing unit and an additional 50‐ton/day acidulation and a 100‐ton/day wastewater treatment unit would be paid back in 24 months. The contour lines of the payback period between 18 and 36 months for the investment between $400,000 and $1,200,000 and the meal price between $200 and $300/ton are also shown. © 2006 American Institute of Chemical Engineers Environ Prog, 2006
Bias in the estimation of non‐linear transformations of the integrated variance of returns
Authors: Harris Richard D. F. , Guermat Cherif
Published: November 2006

Volatility models such as GARCH, although misspecified with respect to the data‐generating process, may well generate volatility forecasts that are unconditionally unbiased. In other words, they generate variance forecasts that, on average, are equal to the integrated variance. However, many applications in finance require a measure of return volatility that is a non‐linear function of the variance of returns, rather than of the variance itself. Even if a volatility model generates forecasts of the integrated variance that are unbiased, non‐linear transformations of these forecasts will be biased estimators of the same non‐linear transformations of the integrated variance because of Jensen's inequality. In this paper, we derive an analytical approximation for the unconditional bias of estimators of non‐linear transformations of the integrated variance. This bias is a function of the volatility of the forecast variance and the volatility of the integrated variance, and depends on the concavity of the non‐linear transformation. In order to estimate the volatility of the unobserved integrated variance, we employ recent results from the realized volatility literature. As an illustration, we estimate the unconditional bias for both in‐sample and out‐of‐sample forecasts of three non‐linear transformations of the integrated standard deviation of returns for three exchange rate return series, where a GARCH(1, 1) model is used to forecast the integrated variance. Our estimation results suggest that, in practice, the bias can be substantial.  Copyright © 2006 John Wiley & Sons, Ltd.
Evaluation of patterns of failure and subjective salivary function in patients treated with intensity modulated radiotherapy for head and neck squamous cell carcinoma
Authors: Daly Megan E. , Lieskovsky YeeYie , Pawlicki Todd , Yau Jervis , Pinto Harlan , Kaplan Michael , Fee Willard E. , Koong Albert , Goffinet Don R. , Xing Lei , Le Quynh‐Thu
Published: November 2006

Background.

Our aim was to correlate patterns of failure with target volume delineations in patients with head and neck squamous cell carcinoma (HNSCC) treated with intensity‐modulated radiation therapy (IMRT) and to report subjective xerostomia outcomes after IMRT as compared with conventional radiation therapy (CRT).

Methods.

Between January 2000 and April 2005, 69 patients with newly diagnosed nonmetastatic HNSCC underwent curative parotid‐sparing IMRT at Stanford University. Sites included were oropharynx (n = 39), oral cavity (n = 8), larynx (n = 8), hypopharynx (n = 8), and unknown primary (n = 6). Forty‐six patients received definitive IMRT (66 Gy, 2.2 Gy/fraction), and 23 patients received postoperative IMRT (60.2 Gy, 2.15 Gy/fraction). Fifty‐one patients also received concomitant chemotherapy. Posttreatment salivary gland function was evaluated by a validated xerostomia questionnaire in 29 IMRT and 75 matched CRT patients >6 months after completing radiation treatment.

Results.

At a median follow‐up of 25 months for living patients (range, 10–60), 7 locoregional failures were observed, 5 in the gross target or high‐risk postoperative volume, 1 in the clinical target volume, and 1 at the junction of the IMRT and supraclavicular fields. The 2‐year Kaplan–Meier estimates for locoregional control and overall survival were 92% and 74% for definitive IMRT and 87% and 87% for postoperative IMRT patients, respectively. The mean total xerostomia questionnaire score was significantly better for IMRT than for CRT patients (p = .006).

Conclusions.

The predominant pattern of failure in IMRT‐treated patients is in the gross tumor volume. Parotid sparing with IMRT resulted in less subjective xerostomia and may improve quality of life in irradiated HNSCC patients. © 2006 Wiley Periodicals, Inc. Head Neck, 2007
Post‐translational synaptic protein modification as substrate for long‐lasting, remote memory: An initial test
Authors: Holahan Matthew R. , Routtenberg Aryeh
Published: November 2006

The current view of the molecular basis for information storage is that post‐translational modification (PTM) of brain proteins is important for the early stages of memory storage and that protein synthesis is necessary for long‐lasting memory. This view has been challenged by the proposal that PTM of synaptic proteins is the critical instructive mechanism underlying both recent as well as long‐lasting memories (Routtenberg and Rekart,2005). As an initial test, a broad spectrum serine/threonine kinase inhibitor (H‐7) was delivered bilaterally to rat anterior cingulate cortex 1 h before a 3 week retention test of contextual fear conditioning. This significantly blocked 21‐Day retention. In the second experiment evaluating extinction of a 21‐Day remote memory, H‐7 injected into mouse medial prefrontal cortex blocked fear extinction. As the H‐7‐induced impairment in 21‐Day retention was indexed by a decrease in freezing, while the extinction blockade by no decrease in freezing, the results could not be ascribed to a direct effect of the drug on behavioral performance. This represents the first demonstration, to our knowledge, that PTM inhibition, here serine/threonine kinase activity, interferes with long‐lasting memory, providing initial support for the PTM model. © 2006 Wiley‐Liss, Inc.
Hydrological versus biogeochemical controls on catchment nitrate export: a test of the flushing mechanism
Authors: Ocampo Carlos J. , Oldham Carolyn E. , Sivapalan Murugesu , Turner Jeffrey V.
Published: November 2006

Deciphering the connection between streamflows and nitrate (NO−3) discharge requires identification of the various water flow pathways within a catchment, and the different time‐scales at which hydrological and biogeochemical processes occur. Despite the complexity of the processes involved, many catchments around the world present a characteristic flushing response of NO−3 export. Yet the controls on the flushing response, and how they vary across space and time, are still not clearly understood. In this paper, the ‘flushing response’ of NO−3 export from a rural catchment in Western Australia was investigated using isotopic (deuterium), chemical (chloride, NO−3), and hydrometric data across different antecedent conditions and time‐scales. The catchment streamflow was at all time‐scales dominated by a pre‐event water source, and the NO−3 discharge was correlated with the magnitude of areas contributing to saturation overland flow. The NO−3 discharge also appeared related to the shallow groundwater dynamics. Thus, the antecedent moisture condition of the catchment at seasonal and interannual time‐scales had a major impact on the NO−3 flushing response. In particular, the dynamics of the shallow ephemeral perched aquifer drove a shift from hydrological controls on NO−3 discharge during the ‘early flushing’ stage to an apparent biogeochemical control on NO−3 discharge during the ‘steady decline’ stage of the flushing response. This temporally variable control hypothesis provides a new and alternative description of the mechanisms behind the commonly seen flushing response. Copyright © 2006 John Wiley & Sons, Ltd.
Wind‐forced seiche events on Great Slave Lake: hydrologic implications for the Slave River Delta, NWT, Canada
Authors: Gardner J. T. , English M. C. , Prowse T. D.
Published: November 2006

A limited amount of research has focused on northern lacustrine deltas and the impacts of basin processes prevalent at these deltas. Wind‐forced seiche events have received little focus in deltaic studies. The Slave River Delta, located on the south shore of Great Slave Lake (GSL), NWT, is an ideal environment to study the prevalence of wind‐forced seiche events and the impact of seiche events on the hydrodynamics of the delta. This paper presents an historical analysis of seiche activity on GSL and the effect of seiches on water levels of the Slave River Delta. The seasonality, frequency, and magnitude of seiche events on the lake are quantified. A description of the wind characteristics that force these events is included. The radial distributary pattern of the delta suggests that water level response to seiche events within the delta may be particularly complex. Hydrologic data from delta distributaries illustrate the temporal and spatial dynamics of seiche response. During the open‐water season, seiche response in the delta is affected by the seasonal hydrograph of the Slave River and wind conditions. Spatially, the slope of delta distributaries governs seiche response. Responses are most similar among zones in the delta rather than among different distributaries. Copyright © 2006 John Wiley & Sons, Ltd.
Interphase effects in dental nanocomposites investigated by small‐angle neutron scattering
Authors: Wilson Kristen S. , Allen Andrew J. , Washburn Newell R. , Antonucci Joseph M.
Published: November 2006

Small‐angle and ultrasmall‐angle neutron scattering (SANS and USANS) were used to characterize silica nanoparticle dispersion morphologies and the interphase in thermoset dimethacrylate polymer nanocomposites. Silica nanoparticle fillers were silanized with varying mass ratios of 3‐methacryloxypropyltrimethoxysilane (MPTMS), a silane that interacts with the matrix through covalent and H‐bonding, and n‐octyltrimethoxysilane (OTMS), a silane that interacts through weak dispersion forces. Interphases with high OTMS mass fractions were found to be fractally rough with fractal dimensions, Ds, between 2.19 and 2.49. This roughness was associated with poor interfacial adhesion and inferior mechanical properties. Mean interparticle distances calculated for composites containing 10 mass % and 25 mass % silica suggest that the nanoparticles treated with more MPTMS than OTMS may be better dispersed than OTMS‐rich nanoparticles. The results indicate that the covalent bonding and H‐bonding of MPTMS‐rich nanoparticles with the matrix are necessary for preparing well‐dispersed nanocomposites. In addition, interphases containing equal masses of MPTMS and OTMS may yield composites with overall optimal properties. Finally, the combined SANS/USANS data could distinguish the differences, as a function of silane chemistry, in the nanoparticle/silane and silane/matrix interfaces that affect the overall mechanical properties of the composites. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Preparation and assessment of glutaraldehyde‐crosslinked collagen–chitosan hydrogels for adipose tissue engineering
Authors: Wu Xuemei , Black Lindsay , Santacana‐Laffitte Guido , Patrick, Charles W.
Published: November 2006

A portfolio of crosslinked chitosan:collagen blends was prepared, and their microarchitecture and water binding capacity were studied to investigate their application for adipose tissue engineering. Glutaraldehyde (GA) concentration had little effect on scaffold morphology or water binding capacity. However, the processing freezing temperature prior to lyophilization affected both. In vitro cytocompatibility of preadipocytes (PAs) was assessed for a candidate collagen:chitosan blend using two assays. Results confirm the viability of PAs on GA‐crosslinked collagen:chitosan scaffolds. A rat subcutaneous pocket assay was employed to assess PA‐seeded scaffolds in vivo. Animal tests proved that PA‐seeded scaffolds were biocompatible, could induce vascularization, and form adipose tissue. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Influence of silanated filler content on the biodegradation of bisGMA/TEGDMA dental composite resins
Authors: Finer Y. , Santerre J.P.
Published: November 2006

It has been shown that an increase in the content of nonsilanated submicron colloidal silica filler particles within dental composites resulted in the release of more bis‐phenol‐A diglycidyl dimethacrylate (bisGMA)‐derived product, bis‐hydroxy‐propoxyphenyl propane, following incubation with cholesterol esterase (CE). This work further investigates the enzyme‐catalyzed biodegradation of fine composite resin systems, containing silanated micron‐size irregular glass fillers, commonly used in clinical restorations. Model composite resin samples (10 or 60% weight fraction silanated barium glass filler, 1 μm average particle size) based on bisGMA/triethylene glycol dimethacrylate (TEGDMA) were incubated in buffer or buffer with CE (pH = 7.0, 37°C) solutions for 32 days. The incubation solutions were analyzed using high‐performance liquid chromatography, UV spectroscopy, and mass spectrometry. Both groups were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray photoelectron spectroscopy. In contrast with previous findings for nonsilanated submicron filler systems, the higher filler containing composite showed an increase in its stability with time, following exposure to esterase and when compared to the lower filler content material. As well, the 60% filler composite leached less unreacted monomer TEGDMA. Since the model composite resins studied here were identical and only the filler content varied, the differences in biostability could be specifically associated with the relative amount of resin/filler distribution. The clinical use of different materials in varied dental applications (ranging from fissure sealant to tooth‐colored highly filled materials) must consider the potential for different degradation profiles to occur as a function of filler content. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Depth‐dependent mechanical properties of enamel by nanoindentation
Authors: Zhou Jikou , Hsiung Luke L.
Published: November 2006

Nanoindentation has recently emerged to be the primary method to study the mechanical behavior and reliability of human enamel. Its hardness and elastic modulus were generally reported as average values with standard deviations that were calculated from the results of multiple nanoindentation testing. In such an approach, it is assumed that the mechanical properties of human enamel are constant, independent of testing parameters, like indent depth and loading rate. However, little is known if they affect the measurements. In this study, we investigated the dependence of the hardness and elastic modulus of human enamel on the indent depth. We found that in a depth range from 100 to 2000 nm the elastic moduli continuously decreased from ∼104 to 70 GPa, and the hardnesses decreased from ∼5.7 to 3.6 GPa. We then considered human enamel as a fiber‐reinforced composite, and used the celebrated rule of mixture theory to quantify the upper and lower bounds of the elastic moduli, which were shown to cover the values measured in the current study and previous studies. Accordingly, we attributed the depth dependence of the hardness and modulus to the continuous microstructure evolution induced by the nanoindenter tip. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Vertical bone augmentation with granulated brushite cement set in glycolic acid
Authors: Mariño F. Tamimi , Torres J. , Tresguerres I. , Jerez L. Blanco , Cabarcos E. López
Published: November 2006

Brushite cements are a biocompatible materials that are resorbed in vivo. A new cement composed of a mixture of monocalcium phosphate (MCP) and β‐tricalcium phosphate (β‐TCP) that sets using glycolic acid (GA) was synthesized and characterized. After setting, the cement composition, derived from X‐ray diffraction, was 83 wt % brushite and 17 wt % β‐TCP with an average brushite crystal size of about 2.6 ± 1.4 μm. The cement has a diametral tensile strength of 2.9 ± 0.7 MPa. Granules prepared from the set‐cement were used as grafting material in bone defects on rabbit calvaria for evaluating in vivo its bone regeneration capacity. Considerable cement resorption, improvement in the bone mineral density, and bone neoformation was observed after 4 weeks of the granules' implantation. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007