bluuebunny/crossref_metadata_2025 huggingface dataset:
Excited‐State Relaxation of Protonated Adenine
Authors: Nolting Dirk , Weinkauf Rainer , Hertel Ingolf V. , Schultz Thomas
Published: March 2007

The excited state dynamics of protonated adenine in the gas phase were investigated by femtosecond pump–probe transient mass spectroscopy. Adenine was protonated in an electrospray ionization source and transferred to a Paul trap. Two femtosecond laser pulses at 266 nm and 800 nm excited the lowest electronic ππ* state and probed the excited‐state dynamics by monitoring ion fragment formation. The measured excited state decay is monoexponential with a lifetime shorter than 161 fs. This agrees with a theoretical prediction of very fast internal conversion via a conical intersection with the ground state.
In Situ ESR and UV/Vis Spectroelectrochemical Study of Eosin Y Upon Reduction with and without Zn(II) Ions
Authors: Goux A. , Pauporté T. , Lincot D. , Dunsch L.
Published: March 2007

The electroreduction of eosin Y on a platinum electrode in deaerated slightly acidic aqueous 0.1 mol L−1 potassium chloride medium is followed in situ by electron spin resonance (ESR) spectroscopy and UV/Vis spectroscopy. The electrochemical formation of a semiquinone radical is proved by both the appearance of an absorbing band at 408 nm, and a strong ESR signal observed during a negative‐going scan. The system is also studied in the presence of ZnII ions due to its importance for understanding the growth mechanism of nanostructured ZnO/Eosin Y hybrid films by electrodeposition; under such conditions the ESR and UV/Vis response of the semiquinone radical is not observed. Zinc (II) ions form a complex with the dye, which is reduced by a fast two‐electron process.
Ascidian embryonic development: An emerging model system for the study of cell fate specification in chordates
Authors: Kumano Gaku , Nishida Hiroki
Published: March 2007

The ascidian tadpole larva represents the basic body plan of all chordates in a relatively small number of cells and tissue types. Although it had been considered that ascidians develop largely in a determinative way, whereas vertebrates develop in an inductive way, recent studies at the molecular and cellular levels have uncovered several similarities in the way developmental fates are specified. In this review, we describe ascidian embryogenesis and its cell lineages, introduce several characteristics of ascidian embryos, describe recent advances in understanding of the mechanisms of cell fate specification, and discuss them in the context of what is known in vertebrates and other organisms. Developmental Dynamics 236:1748–1757, 2007. © 2007 Wiley‐Liss, Inc.
Nestin expression in pancreatic endocrine and exocrine cells of mice lacking glucagon signaling
Authors: Kedees Mamdouh H. , Guz Yelena , Vuguin Patricia M. , Vargas Carlos , Cui Lingguang , Steiner Donald F. , Charron Maureen J. , Teitelman Gladys
Published: March 2007

Nestin, a marker of neural stem cells, is also expressed by cells located in the epithelium of the pancreatic primordium and by a subpopulation of exocrine cells but not by endocrine cells. These findings raised the possibility that the pancreatic epithelium is heterogeneous and comprised of subpopulations of exocrine/nestin‐positive and endocrine/nestin‐negative precursor cells. We examined this issue in two mutant mouse models characterized by protracted expression of several embryonal properties in islet cells. One mutant line comprises mice lacking mature glucagon due to abrogation of proprotein convertase‐2 (PC2−/−), responsible for the conversion of proglucagon into glucagon, while the second line consists of mice with a global deletion of the glucagon receptor (Gcgr−/−). We demonstrate that nestin is transiently expressed by acinar cells and by insulin and glucagon cells of islets of both lines of mice. In addition, the lack of glucagon signaling increased nestin mRNA levels in pancreas of mutant embryos and adult mice. We conclude that nestin+ cells located in the pancreatic primordium generate the cells of the endocrine and exocrine lineages. Furthermore, our results suggest that nestin expression is regulated by glucagon signaling. Developmental Dynamics 236:1126–1133, 2007. © 2007 Wiley‐Liss, Inc.
Myocardium defects and ventricular hypoplasia in mice homozygous null for the Forkhead Box m1 transcription factor
Authors: Ramakrishna Sneha , Kim Il‐Man , Petrovic Vladimir , Malin Dmitriy , Wang I‐Ching , Kalin Tanya V. , Meliton Lucille , Zhao You‐Yang , Ackerson Timothy , Qin Yimin , Malik Asrar B. , Costa Robert H. , Kalinichenko Vladimir V.
Published: March 2007

The Forkhead Box m1 (Foxm1) transcription factor is expressed in cardiomyocytes and cardiac endothelial cells during heart development. In this study, we used a novel Foxm1 −/− mouse line to demonstrate that Foxm1‐deletion causes ventricular hypoplasia and diminished DNA replication and mitosis in developing cardiomyocytes. Proliferation defects in Foxm1 −/− hearts were associated with a reduced expression of Cdk1‐activator Cdc25B phosphatase and NFATc3 transcription factor, and with abnormal nuclear accumulation of the Cdk‐inhibitor p21Cip1 protein. Depletion of Foxm1 levels by siRNA caused altered expression of these genes in cultured HL‐1 cardiomyocytes. Endothelial‐specific deletion of the Foxm1 fl/fl allele in Tie2‐Cre Foxm1 fl/fl embryos did not influence heart development and cardiomyocyte proliferation. Foxm1 protein binds to the −9,259/−9,288‐bp region of the endogenous mouse NFATc3 promoter, indicating that Foxm1 is a transcriptional activator of the NFATc3 gene. Foxm1 regulates expression of genes essential for the proliferation of cardiomyocytes during heart development. Developmental Dynamics 236:1000–1013, 2007. © 2007 Wiley‐Liss, Inc.
Oscillator mechanism of notch pathway in the segmentation clock
Authors: Kageyama Ryoichiro , Masamizu Yoshito , Niwa Yasutaka
Published: March 2007

Somites are formed by periodic segmentation of the presomitic mesoderm (PSM). This periodic event is controlled by the segmentation clock, where Notch signaling plays an essential role. The basic helix–loop–helix factor Hes7, a Notch effector, is cyclically expressed by negative feedback and regulates cyclic expression of Lunatic fringe (Lfng), a Notch modulator. Lfng then seems to periodically inhibit Notch, leading to oscillation in Notch activity. It is thought that these coupled negative feedback loops by Hes7 and Lfng are important for sustained and synchronized oscillations in the PSM. Of interest, another Notch effector, Hes1, is cyclically expressed by many cell types such as neuroblasts, suggesting that this clock is widely distributed and regulates many biological events. This review summarizes the recent finding about roles and mechanism of Notch signaling in the segmentation clock and discusses the significance of Hes1 oscillation in non‐PSM cells. Developmental Dynamics 236:1403–1409, 2007. © 2007 Wiley‐Liss, Inc.
Diversified expression patterns ofautotaxin, a gene for phospholipid‐generating enzyme during mouse and chicken development
Authors: Ohuchi Hideyo , Hayashibaral Yasunori , Matsuda Hironao , Onoi Motoyoshi , Mitsumori Masayuki , Tanaka Masayuki , Aoki Junken , Arai Hiroyuki , Noji Sumihare
Published: March 2007

Autotaxin (ATX), or nucleotide pyrophosphatase‐phosphodiesterase 2, is a secreted lysophospholipase D that generates bioactive phospholipids that act on G protein–coupled receptors. Here we show the expression patterns of theATXgene in mouse and chicken embryos.ATXhas a dynamic spatial and temporal expression pattern in both species and the expression domains during neural development are quite distinct from each other. MurineATX(mATX) is expressed immediately rostral to the midbrain‐hindbrain boundary, whereas chickenATX(cATX) is expressed in the diencephalon and later in the parencephalon‐synencephalon boundary. In the neural tube,cATXis expressed in the alar plate in contrast tomATXin the floor plate.ATXis also expressed in the hindbrain and various organ primordia such as face anlagen and skin appendages of the mouse and chicken. These results suggest conserved and non‐conserved roles for ATX during neural development and organogenesis in these species. Developmental Dynamics 236:1134–1143, 2007. © 2007 Wiley‐Liss, Inc.
Hyperoxia inhibits several critical aspects of vascular development
Authors: Uno Koichi , Merges Carol A. , Grebe Rhonda , Lutty Gerard A. , Prow Tarl W.
Published: March 2007

Normal human retinal vascular development uses angiogenesis and vasculogenesis, both of which are interrupted in the vaso‐obliteration phase of retinopathy of prematurity (ROP). Canine oxygen‐induced retinopathy (OIR) closely resembles human ROP. Canine retinal endothelial cells (ECs) and angioblasts were used to model OIR and characterize the effects of hyperoxia on angiogenesis and vasculogenesis. Cell cycle analysis showed that hyperoxia reduced the number of G1 phase cells and showed increased arrest in S phase for both cell types. Migration of ECs was significantly inhibited in hyperoxia (P < 0.01). Hyperoxia disrupted the cytoskeleton of angioblasts but not ECs after 2 days. Differentiation of angioblasts into ECs (determined by acetylated low‐density lipoprotein uptake) was evaluated after basic fibroblast growth factor treatment. Differentiation of angioblasts into pericytes was determined by smooth muscle actin expression after treatment with platelet‐derived growth factor. Differentiation into ECs was significantly inhibited by hyperoxia (P < 0.0001). The percentage of CXCR4+ cells (a marker for retinal vascular precursors) increased in both treatment groups after hyperoxia. These data show novel mechanisms of hyperoxia‐induced disruption of vascular development. Developmental Dynamics 236:981–990, 2007. © 2007 Wiley‐Liss, Inc.
Lack of galectin‐1 results in defects in myoblast fusion and muscle regeneration
Authors: Georgiadis Vasilios , Stewart Helen J.S. , Pollard Hilary J. , Tavsanoglu Yasemin , Prasad Rathi , Horwood Julia , Deltour Louise , Goldring Kirstin , Poirier Francoise , Lawrence‐Watt Diana J.
Published: March 2007

Galectin‐1 has been implicated in the development of skeletal muscle, being maximally expressed at the time of myofiber formation. Furthermore, in the presence of exogenous galectin‐1, mononuclear myoblasts show increased fusion in vitro. In the current study, we have used the galectin‐1 null mouse to elucidate the role of galectin‐1 in skeletal muscle development and regeneration. Myoblasts derived from the galectin‐1 mutant showed a reduced ability to fuse in vitro. In galectin‐1 null mutants, there was evidence of a delay in muscle fiber development at the neonatal stage and muscle fiber diameter was reduced when compared with wild‐type at the adult stage. Muscle regeneration was also compromised in the galectin‐1 mutant with the process being delayed and a reduced fiber size being maintained. These results, therefore, show a definitive role for galectin‐1 in fusion of myoblasts both in vitro, in vivo, and in regeneration after recovery from induced injury. Developmental Dynamics 236:1014–1024, 2007. © 2007 Wiley‐Liss, Inc.
Rapid accumulation of nucleostemin in nucleolus during newt regeneration
Authors: Maki Nobuyasu , Takechi Katsuaki , Sano Shozo , Tarui Hiroshi , Sasai Yoshiki , Agata Kiyokazu
Published: March 2007

Nucleolar accumulation of nucleostemin in pigmented epithelial cells at the early stage of lens regeneration. In newt regeneration, differentiated cells can revert to stem cell‐like cells in which the proliferative ability and multipotentiality are restored after dedifferentiation. Nucleostemin has been identified in mammals as a nucleolar protein specific to stem cells and cancer cells (Tsai and McKay, 2002). In cover figure, it is shown that nucleostemin (magenta) is rapidly emerged and accumulated in the nucleoli of dedifferentiating pigmented epithelial cells in both dorsal (upper) and ventral iris (lower). From left to right, 0, 2, 4, 6, and 8 days after lentectomy. See Maki et al., Developmental Dynamics 236:941–950
Frying performance of a sunflower/palm oil blend in comparison with pure palm oil
Authors: De Marco Elena , Savarese Maria , Parisini Cristina , Battimo Ilaria , Falco Salvatore , Sacchi Raffaele
Published: March 2007

The aim of this study was to test the performance of a vegetable oil blend formulated as alternative to pure palm oil as frying medium. For this purpose, the evolution of many analytical parameters (free acidity, spectrophotometric indices, total polar components, fatty acid composition, short‐chain fatty acids, tocopherol and tocotrienol content and composition, color, flavor evaluated by means of an electronic nose) of the selected blend (sunflower/palm oil 65 : 35 vol/vol) has been monitored during a prolonged frying process (8 h discontinuous frying without oil replenishment) in comparison to pure palm oil. Sensory attributes of the fried food were also evaluated. The blend proved to keep qualitative parameters comparable to those shown by palm oil during the prolonged frying process. Even if some oxidation indices, such as spectrophotometric indices, short‐chain fatty acids and total polar components, increased faster in the blend, it showed a higher tocopherol content and a lower increment in free fatty acids as compared to pure palm oil. Chips fried in the two oils did not show significantly different sensory profiles.
The use of palm oil in aquaculture feeds for salmonid species
Authors: Ng Wing‐Keong , Tocher Douglas R. , Bell J. Gordon
Published: March 2007

In this overview, our current knowledge and research being conducted on the use of palm oil in the commercial feeds for cold‐water salmonid species such as Atlantic salmon and rainbow trout will be highlighted. Salmonid diets have a high lipid content to provide a source of easily available energy and also n‐3 polyunsaturated fatty acids (PUFA) which is used to maintain membrane fluidity in a cold‐water environment. The culture of salmonid fishes has traditionally depended on marine fish oils for this purpose, but with limited supplies and the rapid increase in salmon production, alternatives to fish oils must be investigated. Research has shown that crude palm oil can be used to replace 100% of added fish oils in salmonid diets without compromising growth performance and feed utilization efficiency, despite reductions in lipid and fatty acid digestibilities that occur during low water temperatures over the winter rearing period. Fatty acid desaturation and elongation activities increased with increasing dietary palm oil and, to a certain extent, decreasing water temperatures. The effects of palm oil on fish health requires further research, but the use of this more saturated vegetable oil may reduce oxidative stress in fish, thereby reducing pathological conditions associated with this physiological state. It is generally known that the fish fillet fatty acid composition directly reflects that of the dietary oil used. Extrapolating from work done with other vegetable oils, the supply of beneficial n‐3 PUFA in salmon fillets to the human consumer can be maintained by using a finishing diet strategy just prior to harvesting, despite significant reductions in these fatty acids when high levels of dietary palm oil are used in grower feeds. Compared to vegetable oils such as soybean or rapeseed oil, palm oil has several advantages in terms of high oil productivity, lower cost, less deposition of undesirable fatty acids such as 18:2(n‐6), superior energy source in the form of saturated and monounsaturated fatty acids, and a high content of natural antioxidants (carotenes and vitamin E). Fillet texture and color were not affected by feeding salmon palm oil‐based diets.
Future prospects for oil palm in the 21st century: Biological and related challenges
Authors: Murphy Denis J.
Published: March 2007

Oil palm is currently at a historic crossroads as regards its future prospects as a versatile global oil crop. In 2005, oil palm became the world's leading commercial source of vegetable oil, and the continued expansion of Asian economies augers well for further growth in production. There are several significant challenges that face the oil palm industry, both biological and non‐biological. The major biological and managerial challenge will be to tackle the stagnating yield that has characterised average plantation output over the past decade. Yield can be enhanced by developing and efficiently propagating/distributing improved germplasm for both large plantations and smallholders. Improved biocontrol of major pests and diseases, such as Ganoderma and rhinoceros beetle, will also have a significant impact. Oil quality can be improved by diversifying fatty acid composition to produce high‐oleate varieties for mainstream edible/oleochemical use, as well as other useful acyl compositions, including nutraceutical components and enhanced vitamin A and E contents for higher‐value niche markets. The whole spectrum of breeding approaches, from DNA marker‐assisted selection to genetic engineering, is being deployed to meet these objectives. One of the potential threats to the future growth of oil palm as a source of high‐quality foods and oleochemicals is the rapid emergence of biodiesel, which might destabilise the industry in the short term and adversely impact on its image and attractiveness for longer‐term investment.
Evaluation of virgin olive oil bitterness by total phenol content analysis
Authors: Beltrán Gabriel , Ruano María T. , Jiménez Antonio , Uceda Marino , Aguilera María P.
Published: March 2007

Bitterness is an important sensory attribute of virgin olive oil (VOO). It is usually assessed by tasting, which is a time‐consuming method and needs trained tasters. Bitterness is related to the phenolic compounds and can be estimated by the measurement of the specific absorbance at 225 nm (K225). This paper proposes to evaluate oil bitterness intensity as estimated from the K225 values measuring the phenol content. A significant relationship between phenol content and K225 as well as a prediction model for bitterness intensity estimation from the phenol content was obtained. Classification of oil bitterness was based on the phenol content. Furthermore, when 12 VOO samples were classified by their bitterness intensities as estimated by the prediction model and by sensory analysis, more than 92% of the oil samples were correctly classified. Therefore, by measuring the phenol content, the bitterness intensity can be estimated and oils can be classified by their bitterness. This model may represent an easy method to evaluate the bitterness intensity without any sensory assessment.
Liquid‐liquid phase separation in acetone solutions of palm olein: Implications for solvent fractionation
Authors: Smith Kevin W. , Cain Fred W. , Favre Loek , Talbot Geoff
Published: March 2007

The quality of palm mid fractions (PMF) obtained by dry fractionation has increased, but the best‐quality PMF for application in many confectionery fats are still produced by solvent fractionation. In the present study, liquid‐liquid phase separation has been observed in acetone solutions both for pure triacylglycerols and for palm olein. The temperature at which phase separation occurs increases as the oil concentration is increased and linearly as the water content of the system is increased. The triacylglycerol compositions of the two liquid phases that form do not differ. However, the oil‐rich phase is depleted with respect to the polar components. The temperature at which liquid‐liquid phase separation occurs is reduced by about 0.2 and 0.4 °C per percent of free fatty acids and diacylglycerols, respectively. When oil‐rich droplets appear, crystallisation occurs within them rather than in the oil‐depleted phase, due to the higher oil concentration. Thus, liquid‐liquid phase separation prior to crystallisation raises the nucleation temperature but may lead to a greater concentration of entrained olein in the filter cake, leading to a poorer‐quality PMF.
Thermal and structural behaviour of crude palm oil: Crystallisation at very slow cooling rate
Authors: Chong Chiew Let , Kamarudin Zukarinah , Lesieur Pierre , Marangoni Alejandro , Bourgaux Claudie , Ollivon Michel
Published: March 2007

The crystallisation behaviour of crude palm oil (CPO) has been examined with a new instrument coupling time‐resolved synchrotron X‐ray diffraction with high‐sensitivity differential scanning calorimetry at cooling rates of 0.1 and 0.4 °C/min from melt temperature to –20 °C, in order to determine the triacylglycerol (TAG) organisations formed as a function of temperature and thermal treatment. At slow cooling rate, CPO TAG sequentially crystallise in apparently two different lamellar structures with double‐chain length of 41.9 Å and a triple‐chain length of 62.8Å stackings of β' type, which are correlated to two main exothermic peaks at 26 and 8 °C, respectively. While a time‐dependent slow β'→β irreversible transition is observed even at low temperature, it only affects a few percent of the TAG population. Subsequent heating at 1 °C/min showed no structural rearrangements of the crystalline forms observed before final melting, indicating that the main moiety of the system is close to equilibrium. Crystallisation at 0.4 °C/min has shown the formation of many additional structures, some of which are evanescent. An unexpected finding was the vicinity of the two lines corresponding to the two 2L (bilayered) structures and the isosbestic point located at 4.42 Å. Only careful analysis allowed the separation of both lines, the coexistence of which was related to the epitaxy/eutectic phenomenon, as evidenced by the simultaneous appearance of the 3L (trilayered) stackings at the same time of the second burst of the 2L stacking and the observation of the isosbestic point. The coexistence of β and β' forms even at high temperature demonstrates that the whole system is not in a two‐phase domain but rather in a three‐phase one (β + β' + liquid) in which all TAG molecules could not fit into a single β' structure. This is likely related with the granular phase separations observed in margarine.
CIEF with hydrodynamic and chemical mobilization for the separation of forms of α‐1‐acid glycoprotein
Authors: Lacunza Izaskun , Diez‐Masa Jose C. , de Frutos Mercedes
Published: March 2007

α‐1‐Acid glycoprotein (AGP) is a protein that exists in different forms, which is due to variations in the amino acid sequence and/or in the glycosidic part of the protein. These differences confer to these forms, among other characteristics, diverse pIs. Changes in these forms of AGP have been correlated to modifications of the pathophysiological conditions of the individuals. One of the analytical techniques employed for their study has been IEF performed in slab gels. CIEF method with hydrodynamic and chemical mobilization, involving an isotachophoretic process, is developed in this work to separate up to 12 bands of forms of standard AGP, which is proposed as a more reproducible, quantitative, less sample‐consuming, and more automated one than conventional IEF. The challenge of this work has been the development of a CIEF method for the separation of bands of a very acidic protein (pI range: 1.8–3.8) in a capillary. Intraday RSD values ≤ 1.7% have been achieved for the relative migration time of the AGP bands to that of an internal standard. For intraday area precision, RSD (%) in the range of 2.70–22.71% for AGP zones accounting for more than 10% of total area of AGP sample has been obtained. As a proof of the potential of the methodology proposed, an AGP sample purified from a pool of sera of patients suffering from ovary cancer is analyzed by CIEF.
Electrophoretic separation of environmentally important phenolic compounds using montomorillonite‐coated fused‐silica capillaries
Authors: Mora Maria F. , García Carlos D.
Published: March 2007

This paper reports a simple procedure for coating fused‐silica capillaries with poly(diallyldimethyl ammonium chloride) and montmorillonite. The coated capillaries were characterized by performing EOF measurements as a function of buffer pH, number of layers of coating, and number of runs (stability). The coated capillaries showed a highly stable μEOF (run‐to‐run RSD less than 1.5%, n = 20), allowing continuous use for several days without conditioning. The coated capillaries were then used for the effective separation of nine environmentally important phenolic compounds showing a significant improvement in the resolution, when compared to bare fused‐silica capillaries. The EOF of the coated capillaries was constant in alkaline solutions (pH ≥ 7), allowing the optimization of the separation conditions of phenolic compounds without significantly affecting the μEOF.
A sheathless poly(methyl methacrylate) chip‐CE/MS interface fabricated using a wire‐assisted epoxy‐fixing method
Authors: Li Fu‐An , Wang Chih‐Hung , Her Guor‐Rong
Published: March 2007

Using a wire‐assisted epoxy‐fixing method, a sheathless CE/MS interface on a poly‐(methyl methacrylate) (PMMA) CE chip has been developed. The sheathless chip‐CE/MS interface utilized a tapered fused‐silica tip and the electrical connection was achieved through a layered coating of conductive rubber. The wire‐assisted method provided facile alignment of channels between the PMMA CE chip and an external capillary sprayer without the need for micromachining. Because the wire was in the channel during fixing, the risk of channel blockage by the epoxy was avoided. This chip CE device has minimal dead volume because the interstitial spaces were filled by a fast‐fixing epoxy resin. The performance of the chip‐CE‐ESI‐MS device was demonstrated with the analysis of peptide mixtures.
Parallel separation of multiple samples with negative pressure sample injection on a 3‐D microfluidic array chip
Authors: Zhang Lei , Yin Xuefeng
Published: March 2007

A simple and powerful microfluidic array chip‐based electrophoresis system, which is composed of a 3‐D microfluidic array chip, a microvacuum pump‐based negative pressure sampling device, a high‐voltage supply and an LIF detector, was developed. The 3‐D microfluidic array chip was fabricated with three glass plates, in which a common sample waste bus (SWbus) was etched in the bottom layer plate to avoid intersecting with the separation channel array. The negative pressure sampling device consists of a microvacuum air pump, a buffer vessel, a 3‐way electromagnet valve, and a vacuum gauge. In the sample loading step, all the six samples and buffer solutions were drawn from their reservoirs across the injection intersections through the SWbus toward the common sample waste reservoir (SWT) by negative pressure. Only 0.5 s was required to obtain six pinched sample plugs at the channel crossings. By switching the three‐way electromagnetic valve to release the vacuum in the reservoir SWT, six sample plugs were simultaneously injected into the separation channels by EOF and electrophoretic separation was activated. Parallel separations of different analytes are presented on the 3‐D array chip by using the newly developed sampling device.
Separation of fluorescent phosphatidyl inositol phosphates by CE
Authors: Mwongela Simon M. , Lee Katherine , Sims Christopher E. , Allbritton Nancy L.
Published: March 2007

Phosphatidyl inositol 4,5‐bisphosphate (PIP2) and phosphatidyl inositol 3,4,5‐trisphosphate (PIP3) labeled with 4,4‐difluoro‐5,7‐dimethyl‐4‐bora‐3a,4a‐diaza‐s‐indacene‐3‐propionic acid (BODIPY FL) on the acyl chain or a phosphatidyl ethanolamine head group were separated by CE with LIF detection. Several methods and capillary‐coating procedures were tested for the separation of these phosphatidyl inositol phosphates (PIPs) at 20°C. Separation of the PIPs in less than 20 min with excellent resolution was achieved using a buffer containing sodium deoxycholate (SDC), 1‐propanol, MgCl2 and the polymer coating reagent, EOTrol™ LR. The efficiency of the optimized method was as high as 1.3×105 plates. The dependence of the separation on the concentration of 1‐propanol, SDC, and MgCl2 was determined. The separation of PIP2 and PIP3 was primarily due to differential binding of the lipids to Mg2+ rather than to different solubilities in the micellar phase. The role of the SDC was to prevent adsorption of the hydrophobic lipids to the capillary wall and thus enhance the efficiency. The fluorescent PIPs are of value for both in vitro and in vivo assays of phospholipid metabolism. In particular, the use of these lipids with the optimized capillary‐based separation will be of utility for drug screening as well as cell‐based assays.
3′‐azido‐3′‐deoxythymidine induces deletions in L5178Y mouse lymphoma cells
Authors: Wang Jianyong , Chen Tao , Honma Masamitsu , Chen Ling , Moore Martha M.
Published: March 2007

3′‐Azido‐3′‐deoxythymidine (AZT), a nucleoside analogue used for the treatment of acquired immunodeficiency syndrome (AIDS), induced a significant dose‐related increase in the thymidine kinase (Tk) mutant frequency (MF) in L5178Y/Tk+/− 3.7.2C mouse lymphoma cells. Treatment with 1 mg/ml (3,742 μM) AZT for 24 hr resulted in a MF of 407 × 10−6 compared to a control MF of 84 × 10−6. The MFs of the large and small colony mutants resulting from AZT exposure were 142 × 10−6 and 265 × 10−6, respectively. One hundred and fifty mutants from the 1 mg/ml (3,742 μM) AZT‐treated culture and sixty‐nine mutants from independent untreated cultures were isolated and analyzed. LOH analysis using a heteromorphic microsatellite locus located in the Tk gene was performed to determine the presence or absence of the Tk+ allele. Eight other microsatellite markers spanning the entire mouse chromosome 11 also were examined for heterozygosity to determine the extent of LOH. In addition, Tk gene dosage analysis was conducted using Real‐Time PCR in those mutants showing LOH at the Tk locus. The presence of only one Tk allele based on Real‐Time PCR indicated that the mutant resulted from deletion while the presence of two alleles was consistent with a recombination event. More mutants from the AZT‐treated culture showed Tk LOH than did independent mutants from the untreated cultures (91% vs. 64%) and the induced mutants also showed distinct chromosome 11 LOH patterns. The mutation spectrum of mutants from AZT‐treated cells was also significantly different from that of spontaneous mutants. More deletions and fewer intragenic mutations were observed in the mutants from the AZT‐treated culture than independent mutants from the untreated control. Our data indicate that AZT primarily induced LOH mutations in L5178Y mouse lymphoma cells and a large number of LOH mutations resulted from deletions. Environ. Mol. Mutagen., 2007. Published 2007 Wiley‐Liss, Inc.
Mutagenicity of zidovudine, lamivudine, and abacavir following in vitro exposure of human lymphoblastoid cells or in utero exposure of CD‐1 mice to single agents or drug combinations
Authors: Torres Salina M. , Walker Dale M. , Carter Meghan M. , Cook Dennis L. , McCash Consuelo L. , Cordova Edmund M. , Olivero Ofelia A. , Poirier Miriam C. , Walker Vernon E.
Published: March 2007

Experiments were performed to investigate the impact of zidovudine (AZT), lamivudine (3TC), and abacavir (ABC) on cell survival and mutagenicity in two reporter genes, hypoxanthine‐guanine phosphoribosyltransferase (HPRT) and thymidine kinase (TK), using cell cloning assays for assessing the effects of individual drugs/drug combinations in (1) TK6 human lymphoblastoid cells exposed in vitro and (2) splenic lymphocytes from male CD‐1 mice exposed transplacentally on days 12–18 of gestation. In TK6 cells, dose‐related increases in HPRT and TK mutant frequencies were found following 3 days of exposure to AZT or 3TC alone (33, 100, or 300 μM), or to equimolar amounts of AZT‐3TC. Compared with single drug exposures, AZT‐3TC coexposures generally yielded enhanced elevations in HPRT and TK mutant frequencies. Mutagenicity experiments with ABC alone, or in combination with AZT‐3TC, were complicated by the extreme cytotoxicity of ABC. Exposure of cells either to relatively high levels of AZT‐3TC short‐term (100 μM, 3 days), or to peak plasma‐equivalent levels of AZT‐3TC for an extended period (10 μM, 30 days), resulted in similar drug‐induced mutagenic responses. Among sets of mice necropsied on days 13, 15, or 21 postpartum, Hprt mutant frequencies in T‐cells were significantly elevated in the AZT‐only (200 mg/kg bw/day) and AZT‐3TC (200 mg AZT + 100 mg 3TC/kg bw/day) groups at 13 days of age. These results suggest that the mutagenicity by these nucleoside analogs is driven by cumulative dose, and raises the question of whether AZT‐3TC has greater mutagenic effects than AZT alone in perinatally exposed children. Environ. Mol. Mutagen. © 2007 Wiley‐Liss, Inc.
Frequency of Hprt mutant lymphocytes and micronucleated erythrocytes in p53‐haplodeficient mice treated perinatally with AZT and AZT in combination with 3TC
Authors: Dobrovolsky Vasily N. , Shaddock Joseph G. , Mittelstaedt Roberta A. , Bishop Michelle E. , Lewis Sherry M. , Lee Fei W. , Aidoo Anane , Leakey Julian E.A. , Dunnick June K. , Heflich Robert H.
Published: March 2007

Azidothymidine (AZT) is a nucleoside reverse transcriptase inhibitor (NRTI) that is used for reducing mother‐to‐child transmission of human immunodeficiency virus I. Combinations of AZT and 3′‐thiacytidine (3TC) are even more effective than AZT alone. AZT, however, is a mutagen and carcinogen in rodent models and 3TC can increase the genotoxicity of AZT. Since p53 plays a key role in human and mouse tumorigenesis, p53‐haplodeficient mice are currently being evaluated as a model for assessing the carcinogenicity of perinatal exposure to NRTIs. In the present study, male C57BL/6 p53+/+ and p53−/− mice were mated with C3H p53+/+ females; the pregnant females were treated on gestation day 12 through parturition with 40, 80, and 160 mg/kg of AZT or a combination of 160 mg/kg AZT and 100 mg/kg 3TC (AZT‐3TC); the p53+/+ and p53+/− offspring were treated daily after birth through postnatal day (PND) 28. The frequencies of micronucleated reticulocytes (MN‐RETs) and micronucleated normochromatic erythrocytes (MN‐NCEs) were determined on PND1, PND10, and PND28; the frequency of Hprt mutant lymphocytes was measured on PND28. The frequencies of MN‐RETs and MN‐NCEs were increased in treated animals at all time points; there were no differences in the responses of p53+/+ and p53+/− animals treated with identical doses of NRTIs. After correction for clonal expansion, both AZT and AZT‐3TC treatments induced small but significant increases in the frequency of Hprt mutant lymphocytes in p53+/− mice, but not in p53+/+ mice. The data indicate that p53 haplodeficiency affects the genotoxicity of NRTIs; thus, p53+/− mice may be a sensitive model for evaluating the carcinogenicity of perinatal exposure to NRTIs. Environ. Mol. Mutagen., 2007. Published 2007 Wiley‐Liss, Inc.
Relative mutagenic potencies of several nucleoside analogs, alone or in drug pairs, at the HPRT and TK loci of human TK6 lymphoblastoid cells
Authors: Carter Meghan M. , Torres Salina M. , Cook Dennis L. , McCash Consuelo L. , Yu Mia , Walker Vernon E. , Walker Dale M.
Published: March 2007

Experiments were performed to investigate the impact of didanosine (ddI), lamivudine (3TC), and stavudine (d4T) on cell survival and mutagenicity in two reporter genes, hypoxanthine‐guanine phosphoribosyltransferase (HPRT) and thymidine kinase (TK), using a cell cloning assay for assessing the effects of individual nucleoside analogs (NRTIs)/drug combinations in human TK6 B‐lymphoblastoid cells. Three‐day treatments with 0, 33, 100, or 300 μM ddI, 3TC, or ddI‐3TC produced positive trends for increased HPRT and TK mutant frequencies. While dose‐related trends were too small to reach significance after treatments with d4T or d4T‐3TC, pairwise comparisons with control cells indicated that exposure to 100 μM d4T or d4T‐3TC caused significant elevations in HPRT mutants. Measurements of mutagenicity in cells exposed to d4T (or d4T‐3TC) were complicated by the cytotoxicity of this NRTI. Enhanced increases in mutagenic responses to combined NRTI treatments, compared with single drug treatments, occurred as additive to synergistic effects in the HPRT gene of cells exposed to 100 μM ddI‐3TC or 100 μM d4T‐3TC, and in the TK gene of cells exposed to 100 or 300 μM ddI‐3TC. Comparisons of these data to mutagenicity studies of other NRTIs in the same system (Meng Q et al. [2000c]: Proc Natl Acad Sci USA 97:12667–126671; Torres SM et al. [2007]: Environ Mol Mutagen) indicate that the relative mutagenic potencies for all drugs tested to date are: AZT‐ddI > ddI‐3TC > AZT‐3TC ≅ AZT‐3TC‐ABC (abacavir) > AZT ≥ddI > d4T‐3TC > 3TC > d4T ≥ ABC. These collective data suggest that all NRTIs with antiviral activity against HIV‐1 may cause host cell DNA damage and mutations, and impose a cancer risk. Environ. Mol. Mutagen., 2007. © 2007 Wiley‐Liss, Inc.
Plasma and cellular markers of 3′‐azido‐3′‐dideoxythymidine (AZT) metabolism as indicators of DNA damage in cord blood mononuclear cells from infants receiving prepartum NRTIs
Authors: Meng Quanxin , Olivero Ofelia A. , Fasco Michael J. , Bellisario Ronald , Kaminsky Laurence , Pass Ken A. , Wade Nancy A. , Abrams Elaine J. , Nesel Carol J. , Ness Roberta B. , Bigbee William L. , O'Neill J. Patrick , Walker Dale M. , Poirier Miriam C. , Walker Vernon E. ,   for the Study Team
Published: March 2007

Several systemic and cellular markers of 3′‐azido‐3′‐dideoxythymidine (AZT) metabolism and AZT incorporation into nuclear DNA were measured in cord blood from uninfected infants born to HIV‐1‐infected mothers receiving prepartum therapies based on AZT or AZT in combination with 2′,3′‐dideoxy‐3′‐thiacytidine (3TC). In addition, the relationships among these pharmacological end points, levels of AZT‐DNA incorporation, and the previously reported mutagenic responses in these infants were evaluated. AZT‐ and 3TC‐specific radioimmunoassays (RIAs), or HPLC coupled with AZT‐RIA, were used to measure plasma levels of AZT and the AZT‐glucuronide, and cellular levels of AZT, phosphorylated AZT, and DNA incorporation of AZT or 3TC in cord blood mononuclear cells from treated infants compared with unexposed controls born to HIV‐uninfected mothers. Fewer infants had detectable AZT‐DNA incorporation levels in the group exposed to AZT (71%; n = 7) compared with those receiving AZT‐3TC (100%; n = 21), and the mean AZT‐DNA incorporation for AZT‐exposed infants (14.6 ± 6.3 AZT/106 nucleotides) was significantly lower than that in AZT‐3TC exposed infants (51.6 ± 10.2 AZT/106 nucleotides; P = 0.028). Low levels of 3TC‐DNA incorporation found in a few AZT‐3TC‐exposed newborns correlated with AZT‐DNA incorporation values in the same samples. Among the metabolites studied, there were positive correlations between levels of AZT‐diphosphate and AZT‐triphosphate, and AZT‐triphosphate and AZT‐DNA incorporation, in nucleoside analog‐exposed infants. Levels of AZT‐DNA incorporation, however, did not correlate well with the reported frequencies of somatic mutations in the same population of nucleoside analog‐treated children. While these data support the continued use of AZT‐based therapies during pregnancy, infants receiving prepartum AZT should be monitored long‐term for adverse health effects. Environ. Mol. Mutagen., 2007. © 2007 Wiley‐Liss, Inc.
Effect of self‐weight and vertical acceleration on the behaviour of tall structures during earthquake
Authors: Iyengar R. N. , Shinozuka M.
Published: March 2007

The effect of self‐weight and vertical ground acceleration during earthquakes on vertical cantilevers has been studied. The input is taken to be a bivariate normal random process, digitally simulated on a computer. The tip deflection, base moment and shear force have been obtained numerically for three structures of different natural frequencies. It is found that the presence of self‐weight and vertical ground excitation could alter these three quantities considerably. This leads to the conclusion that with tall structures a refined analysis, similar to the one presented here, is advisable.
Earthquake design considerations in reinforced concrete columns
Authors: Hisada Toshihiko , Ohmori Nobutsugu , Bessho Satoshi
Published: March 2007

Damages resulting from the Tokachi‐Oki earthquake of 1968 demonstrated that many code‐designed reinforced concrete columns do not have adequate earthquake resistance. A review of Japanese research revealed that the axial force ratio, the moment arm ratio, and the type and ratio of transverse reinforcement control the resistance and ductility of concrete columns. A recent experimental study at the Kajima Institute of Construction Technology evaluated the resistance of columns with three types of transverse reinforcement and three reinforcement ratios subjected to repeated alternating loads. Tied and spiral columns proved to be superior to hooped columns.
Measurements of sonic boom responses of structures due to concorde
Authors: Webb D. R. B.
Published: March 2007

Measurements have been made of the responses of twelve different buildings and one cliff to the sonic booms produced during ten supersonic flights by Concorde 002 along the west coast route. Measurements were made of the levels of induced vibration and of any permanent movements of existing defects. The dynamic measurements show that, with the exception of roof structures, the vibration levels were generally similar to those produced by environmental loads. On roof structures, the sonic boom causes vibrations some two to three times those of the normal environment. The static measurements show that slow movements occur in the buildings due to temperature changes but none could be related to the sonic boom. No significant damage was observed at the monitored sites.
Desert pavement dynamics: numerical modeling and field‐based calibration
Authors: Pelletier Jon D. , Cline Michael , DeLong Stephen B.
Published: March 2007

Desert pavements are widely used as a relative surface‐dating tool because they are progressively better developed on surfaces ranging from thousands to hundreds of thousands of years in age. Recent work, however, has highlighted the dynamic nature of pavements and undermined their use as surface‐age indicators. Quade (2001) proposed that latest Pleistocene vegetation advances destroyed all Mojave Desert pavements above 400 m elevation, making all such pavements Holocene in age. In an effort to reconcile young‐pavement evidence with their widespread use as Pleistocene surface‐age indicators, we developed a numerical model based on the classic conceptual model in which pavements co‐evolve with their underlying eolian epipedons over millennial timescales. In this co‐evolutionary process, fine‐grained eolian deposition and Av‐horizon development within the eolian epipedon promotes surface clast motion and pavement development, enhancing the eolian‐sediment‐trapping ability of the pavement in a positive feedback. Model results illustrate the multi‐scale nature of pavement dynamics: pavements may require tens of thousands of years to fully develop from a newly abandoned alluvial surface, but may heal over timescales of decades to centuries if a mature eolian epipedon is present. As such, there is no inconsistency between rapid pavement healing and a Pleistocene age for the underlying alluvial surface.

To calibrate the model, we conducted surficial geologic mapping and pavement‐sedimentological analysis on two desert piedmonts. Our study areas include both proximal and distal fan environments, illustrating the role of parent‐material texture in controlling the mode of pavement formation. Using available geochronology, our work provides a rigorous calibration of pavement formation rates in our study areas and provides evidence supporting the use of pavements as local relative surface‐age indicators over Holocene to late Pleistocene timescales. Copyright © 2007 John Wiley & Sons, Ltd.
Sandstone response to salt weathering following simulated fire damage: a comparison of the effects of furnace heating and fire
Authors: McCabe S. , Smith B. J. , Warke P. A.
Published: March 2007

Fire has long been recognized as an agent of rock weathering. Our understanding of the impact of fire on stone comes either from early anecdotal evidence, or from more recent laboratory simulation studies, using furnaces to simulate the effects of fire. This paper suggests that knowledge derived from simulated heating experiments is based on the pre‐conceptions of the experiment designer – when using a furnace to simulate fire, the operator decides on the maximum temperature and the duration of the experiment. These are key factors in determining the response of the stone to fire, and if these are removed from real‐world observations then knowledge based on these simulations must be questioned.

To explore the differences between heating sandstone in a furnace and a real fire, sample blocks of Peakmoor Sandstone were subjected to different stress histories in combination (lime rendering and removal, furnace heating or fire, frost and salt weathering). Block response to furnace heating and fire is discussed, with emphasis placed on the non‐uniformity of the fire and of block response to fire in contrast to the uniform response to surface heating in a furnace.

Subsequent response to salt weathering (by a 10% solution of sodium chloride and magnesium sulphate) was then monitored by weight loss. Blocks that had experienced fire showed a more unpredictable response to salt weathering than those that had undergone furnace heating – spalling of corners and rapid catastrophic weight loss were evidenced in blocks that had been subjected to fire, after periods of relative quiescence. An important physical side‐effect of the fire was soot accumulation, which created a waxy, relatively impermeable layer on some blocks. This layer repelled water and hindered salt ingress, but eventually detached when salt, able to enter the substrate through more permeable areas, concentrated and crystallized behind it, resulting in rapid weight loss and accelerated decay. Copyright © 2007 John Wiley & Sons, Ltd.
Hedging under the influence of transaction costs: An empirical investigation on FTSE 100 index options
Authors: Gregoriou Andros , Healy Jerome , Ioannidis Christos
Published: March 2007

The Black–Scholes (BS; F. Black & M. Scholes, 1973) option pricing model, and modern parametric option pricing models in general, assume that a single unique price for the underlying instrument exists, and that it is the mid‐ (the average of the ask and the bid) price. In this article the authors consider the Financial Times and London Stock Exchange (FTSE) 100 Index Options for the time period 1992–1997. They estimate the ask and bid prices for the index, and show that, when substituted for the mid‐price in the BS formula, they provide superior option price predictors, for call and put options, respectively. This result is reinforced further when they .t a non‐parametric neural network model to market prices of liquid options. The empirical .ndings in this article suggest that the ask and bid prices of the underlying asset provide a superior fit to the mid/closing price because they include market maker's, compensation for providing liquidity in the market for constituent stocks of the FTSE 100 index. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:471–494, 2007
Long memory in commodity futures volatility: A wavelet perspective
Authors: Elder John , Jin Hyun J.
Published: March 2007

The authors reexamine the volatility of agricultural commodity futures for evidence of fractional integration, providing new empirical results and extending the extant literature in important dimensions. First, they utilize two relatively new estimators based on wavelets, which are generally superior to, for example, the popular estimator by J. Geweke and S. Porter‐Hudak (GPH; 1983) and exact maximum likelihood estimators (MLEs) on the basis of mean squared error (MSE). Second, they provide simulations to contrast their point estimates with those obtained by a fractionally integrated GARCH (generalized autoregressive conditional heteroscedasticity) model. Third, they conduct a wavelet coef.cient decomposition of futures volatility. They .nd that futures volatilities display the self‐similarity property consistent with long memory and that futures volatilities exhibit persistent long memory with .nite unconditional variance. © 2007 Wiley Periodicals, Inc. Jrl Fut Mark 27:411–437, 2007