bluuebunny/crossref_metadata_2025 huggingface dataset:
Macro‐, Micro‐, Nano‐ and Crystal Structures of a Homodinuclear Complex [NH3(CH2)3NH3]2{Na2[(C6H4O2)2](C6H4O2H)2}
Authors: Lu Xiao‐Ming , Wei Chun‐Xia , Wang Zhen
Published: August 2007

A homodinuclear complex (NH3CH2CH2CH2NH3)2{Na2[(C6H4O2)2](C6H4O2H)2} (1) has been synthesized by a solution‐based self‐assembly route. It crystallized in monoclinic system with space groupP21/c. Every sodium ion coordinates in a tetragonal prism fashion with two O atoms of a terminal chelating catecholate ligand and three O atoms from two bridging catecholate ligands. Two neighboring NaO5tetragonal prisms are edge‐shared and centrosymmetric with regard to the inversion center to form a binuclear cluster {Na2[(C6H4O2)2](C6H4OOH)2}4−anion. The complex anions were aligned parallelly by π‐π interaction and linked with the protonated 1,3‐propylenediamine through hydrogen bonds which were assembled into a multi‐lamellar structure with channels. The crystal exhibits rectangular geometry with an interior triangle hollow structure under optical microscopy. And the scanning electron microscopy (SEM) indicates that the wall of the tubes shows multi‐lamella morphologies. Further, the transmission electron microscopy (TEM) reveals that the crystal is composed of multi‐lamellar nano‐tubes with diameters less than 100 nm. The molecular structure of the complex was compared with that of its isomer complex2.
A Highly Sensitive Spectrophotometric Assay of Bleomycins Based on the Fading Reaction of Some Halofluorescein Dyes
Authors: Liu Jiang‐Tao , Liu Zhong‐Fang , Hu Xiao‐Li , Kong Ling , Liu Shao‐Pu
Published: August 2007

In weak acidic medium, anticancer antibiotics bleomycin A5 (BLMA5) and bleomycin A2 (BLMA2) can react with halofluorescein dyes such as erythrosin (Ery), eosin Y (EY), eosin B (EB) and rose bengal (RB) by virtue of electrostatic attraction and hydrophobic force to form the ion‐association complexes, which can result in the fading reactions of four halofluorescein dyes. The maximum fading wavelengths of these four dyes were located at 527 nm for Ery, 515 nm for EY, 517 nm for EB and 546 nm for RB, respectively. The decrements of absorbance ((A) were directly proportional to the concentrations of bleomycin in a certain range. A new method for the determination of bleomycins anticancer drugs based on fading reactions of halofluorescein dyes has been developed. The method was not only highly sensitive but also simple and rapid. The molar absorptivities (ε) ranged from 1.5×105 to 7.5×105 L·mol−1·cm−1. It was applied to determination of the bleomycins in human serum, urine and rabbit serum samples. In this work, the spectral properties and the optimum reaction conditions were investigated. The structure of ion‐association complexes and the reaction mechanism were discussed.
Simple Approach to the Highly Stereoselective Synthesis of trans‐1,2‐Cyclopropane Derivatives
Authors: Zhang Hui , Cao Wei‐Guo , Ren Zhong‐Jiao , Chen Jie , Sun Ru‐Shu , Hu Ji‐Rong , Qian Jia‐Xian , Deng Hong‐Mei
Published: August 2007

In the presence of KF·2H2O, furoylmethyltriphenylarsonium bromide (1a) or thienoylmethyltriphenylarsonium bromide (1b) reacted with 2‐[(un)substituted benzylidene]malononitrile (2) in chloroform at room temperature to give trans‐3,3‐dicyano‐1‐furoyl‐2‐[(un)substituted phenyl]cyclopropane (3a) or trans‐3,3‐dicyano‐1‐thienoyl‐2‐[(un)substituted phenyl]cyclopropane (3b) respectively in good yield with high stereoselectivity. The structures of product 3 were confirmed by IR, MS, 1H NMR, 1H‐1H COSY and microanalysis. The relative configuration of product 3 was determined by 1H‐1H NOESY technique. The mechanism for the formation of product 3 was also proposed.
One‐Pot Synthesis of 1,2,3‐Triazoles using Polymer‐Supported Propyne in Aqueous Solution
Authors: Shang Yong‐Jia , Ren Lian‐Bing , Wang Dong‐Mei
Published: August 2007

A practical and efficient liquid‐phase synthesis of 1,2,3‐triazoles using poly(ethylene glycol) as support in aqueous solution was described. The title compounds, 1,2,3‐triazoles 5 were obtained by a one‐pot three‐component 1,3‐dipolar cycloaddition reaction in middle yields. In addition, a series of unexpected products 7 of Sonogashira reaction were also formed under the same condition.
Genomic profile of chronic myelogenous leukemia: Imbalances associated with disease progression
Authors: Brazma D. , Grace C. , Howard J. , Melo J. V. , Holyoke T. , Apperley J. F. , Nacheva E. P.
Published: August 2007

The expression of the chimeric BCR/ABL1 fusion gene resulting from t(9;22)(q34;q11) in chronic myelogenous leukemia (CML) is necessary for malignant transformation, but not sufficient to maintain disease progression. The appearance of various chromosomal and molecular alterations in the accelerated and terminal phase of CML is well documented, but evidence for causal relationship is largely lacking. We carried out a genome wide screening at a resolution of 1 Mb of 54 samples at different stages of CML together with 12 CML cell lines and found that disease progression is accompanied by a spectrum of recurrent genome imbalances. Among the most frequent are losses at 1p36, 5q21, 9p21, and 9q34 and gains at 1q, 8q24, 9q34, 16p, and 22q11, all of which were located with higher precision within the genome than previously possible. These genome imbalances are unique to CML cases with clinically manifested or suspected accelerated/blast stage alike, but not seen in chronic phase samples. Previously unrecognized cryptic imbalances occurring within the Ph‐chromosome were also detected, although further scrutiny is required to pin‐point gene involvement and seek association with disease features. Importantly, some of these imbalances were seen in the CD34(+) cells but not in the whole BM samples of patients in accelerated phase. Taken together, these findings highlight the potential of screening CD34(+) cells for genome wide imbalances associated with disease progression. Finally, the numerous single copy number variations recorded, many unique to this cohort of patients, raise the possible association of genome polymorphism and CML. © 2007 Wiley‐Liss, Inc.
Modelling of meteorological conditions at an urban scale for the PUMA campaigns
Authors: Cai X.‐M. , McGregor G. R. , Harrison R. M. , Ryall D.
Published: August 2007

In this paper, a comparison of modelled and observed surface wind and temperature for two campaigns of the PUMA (Pollution of Urban Midlands Atmosphere) project is presented. The Regional Atmospheric Modelling System (RAMS) was configured for the West Midlands conurbation (WM), UK, to have two nested grids with a mesh size of 2 km for the inner grid which is embedded in the outer grid with a mesh size of 8 km. Statistical evaluation of the model results against observational data of wind speed, direction and temperature was conducted. In general, the model's performance is better in the summer campaign than in the winter campaign. The results suggest that the quality of the prediction is sensitive to whether or not cloud cover is captured by the model under winter conditions. Although the topography of the region is relatively flat, some spatial patterns of wind and temperature may exist under stagnant conditions during the summer and winter seasons. Under summer conditions, the spatial patterns are associated with convective eddies or rolls during daytime, while under winter conditions, the spatial patterns are closely linked to stability and topography. The modelled results of such winter conditions for the inner grid reveal subtle spatial patterns at a scale smaller than 10 km near hills and valleys with differences in elevation of a few hundred metres. Copyright © 2007 Royal Meteorological Society
Strategies to enhance patient‐centred care in a cardiothoracic surgical unit
Authors: Bouras Christina , Barrett Catherine
Published: August 2007

This article describes a project undertaken to enhance patient‐centred care in a cardiothoracic surgical unit in Melbourne. In particular, the article describes the implementation of a transdisciplinary patient assessment tool and interdisciplinary team meetings to enhance the understanding of the patient's experience of illness and to improve the coordination of care. Copyright © 2007 John Wiley & Sons, Ltd.
HIV‐1 protease and HIV‐1 integrase inhibitory substances from Eclipta prostrata
Authors: Tewtrakul Supinya , Subhadhirasakul Sanan , Cheenpracha Sarot , Karalai Chatchanok
Published: August 2007

The bioassay‐guided fractionation for anti‐HIV‐1 integrase activity led to the isolation of six compounds from the whole plant extract of Eclipta prostrata extract. They were identified as 5‐hydroxymethyl‐(2,2′:5′,2″)‐terthienyl tiglate (1), 5‐hydroxymethyl‐(2,2′:5′,2″)‐terthienyl agelate (2), 5‐hydroxymethyl‐(2,2′:5′,2″)‐terthienyl acetate (3), ecliptal (4), orobol (5) and wedelolactone (6). Of these, compound 6 showed the highest activity against HIV‐1 integrase (IN) with an IC50 value of 4.0 ± 0.2 µm, followed by compound 5 (IC50 = 8.1 ± 0.5 µm), whereas the four terthiophene compounds (1–4) were inactive (IC50 > 100 µm). Regarding HIV‐1 protease (PR) inhibitory activity, compound 1 exhibited appreciable activity against HIV‐1 PR with an IC50 of 58.3 ± 0.8 µm, followed by compound 4 (IC50 = 83.3 ± 1.6 µm) and compound 3 (IC50 = 93.7 ± 0.8 µm), while compounds 2, 5 and 6 were inactive against HIV‐1 PR (IC50 > 100 µm). This is the first report of anti‐HIV‐1 IN activities for wedelolactone (6), a coumarin derivative, and orobol (5), an isoflavone derivative. This study supports the use of E. prostrata in AIDS patients, which is in accord with its traditional use by Thai traditional doctors for curing blood related diseases. Copyright © 2007 John Wiley & Sons, Ltd.
Multiple lines of evidence for the beneficial effects of environmental flows in two lowland rivers in Victoria, Australia
Authors: Lind P. R. , Robson B. J. , Mitchell B. D.
Published: August 2007

The aim of this study was to identify whether environmental flows released into two lowland rivers (the Glenelg and Wimmera Rivers, western Victoria, Australia) during the spring to autumn period had successfully ameliorated the negative effects of multiple human impacts. Macroinvertebrates and a range of physico‐chemical variables were sampled from three reaches in each river. Both rivers were sampled during three environmental release seasons with average‐sized releases (1997–1998, 1998–1999 and 2001–2002) and two drought seasons with limited releases (1999–2000 and 2000–2001). The effects of releasing average‐sized environmental flows on macroinvertebrates and physico‐chemical variables were assessed by comparison with data from the two drought seasons. For the Glenelg River, data from a reference season prior to the release of environmental flows (1995–1996) was also compared to data from the five environmental flow seasons. Multivariate analyses revealed four pieces of evidence indicating that the release of environmental flows effectively slowed the process of environmental degradation in the Glenelg River but not in the Wimmera River: (1) the magnitude of the river discharge was dependent on the size of environmental flow releases; (2) in the Wimmera River, water quality deteriorated markedly during the two drought seasons and correlated strongly with macroinvertebrate assemblage structure, but this was not observed in the Glenelg River; (3) the taxonomic composition of the macroinvertebrate assemblages among contrasting flow release seasons reflected the severe deterioration in water quality of the Wimmera River; (4) despite two drought seasons with minimal environmental flow releases, the macroinvertebrate assemblage in the Glenelg River did not differ from the average‐release seasons, nor did it return to a pre‐environmental flows condition. Therefore, it appears that environmental flow releases did sustain the macroinvertebrate assemblage and maintain reasonable water quality in the Glenelg River. However, in the Wimmera River, release volumes were too small to maintain low salinities and were associated with marked changes in the macroinvertebrate assemblage. Therefore, there are multiple lines of evidence that environmental flow releases of sufficient magnitude may slow the process of degradation in a regulated lowland river. Copyright © 2007 John Wiley & Sons, Ltd.
Isomerization studies: II. Thermal alteration of oleic acid and methyl oleate in the presence of mineral catalysts
Authors: Eisner A. , Barr P. A. , Foglia T. A.
Published: August 2007

A structure analysis has been conducted on the distillable fraction (67–71%) obtained from the clay catalyzed isomerization of methyl oleate and oleic acid. The method of analysis involved the combined use of reductive ozonolysis, urea adduction, and gas liquid chromatography‐mass spectrometry. The results of this study indicate that the original unsaturation of the fatty acid is mostly retained, but less than the theoretical amount of hydrogen is absorbed when the products are subjected to low pressure catalytic hydrogenation. These results in conjunction with the gas liquid chromatography‐mass spectrometry data suggest that branching of the carbon chain has occurred.
Autoxidative stability of rendered fat from growing and mature steers fed protected safflower oil
Authors: Kimoto W. I. , Ellis R. , Wasserman A. E. , Oltjen R.
Published: August 2007

Growing and mature steers with increased linoleic acid (18∶2) in their adipose tissues were reared by the Nutrition Institute, U.S. Department of Agriculture. The 18∶2 content of rendered fats from these animals fed protected safflower oil varied from 6.5–20.6% and from 3.4–5.8% for the growing and mature steers, respectively. Increasing the 18∶2 levels resulted in decreased stability to autoxidation of the rendered subcutaneous fats.
Isolation and identification of oxidation product of 2,6‐Di‐(tert‐butyl)‐4‐methylphenol from polyethylene film
Authors: Daun H. , Gilbert S. G. , Giacin J.
Published: August 2007

2,6‐Di‐(tert‐butyl)‐4‐methylphenol is a widely used antioxidant in the production of polyethylene. An oxidation product of this antioxidant was isolated from aged polyethylene film and purified by preparative thin layer chromatography. This compound was identified as 3,3′, 5,5′‐tetra‐bis(tert‐butyl)‐stilbenequinone with the aid of IR‐ and mass spectroscopy. The generation of this oxidation product can lead to the discoloration of polyethylene film, and its formation can be catalyzed by contact with carbon black.
Metabolism of gossypol, biosynthesized from methyl‐14C‐and carboxyl‐14C‐labeled sodium acetate, in rat
Authors: Skutches Charles L. , Smith F. H.
Published: August 2007

Stereospecifically labeled radioactive gossypol was biosynthesized by incubating cotton seedlings with either methyl‐14C‐ or carboxyl‐14C‐labeled sodium acetate. The respective products were purified as gossypol acetic acid. Each radioactive gossypol acetic acid preparation was dissolved in oil and administered by stomach tube to two rats. A negligible amount of radioactivity was found in the expired air of the rats receiving the gossypol biosynthesized from 1‐14C‐sodium acetate; however, a significant quantity of radioactivity was found in the expired air of rats that received gossypol labeled from 2‐14C‐acetate. This indicated that the binaphthalene nucleus of the gossypol molecule was not degraded to CO2 in the rat. A low level of radioactivity was found in the urine of rats administered either gossypol preparation. In each rat there was radioactivity found in all the tissues that were analyzed; however, the major portion of the radioactivity was excreted in the feces.
A mechanism of Munc18b–syntaxin 3–SANP25 complex assembly in regulated epithelial secretion
Authors: Liu Ya , Ding Xia , Wang Dongmei , Deng Hui , Feng Mingye , Wang Min , Yu Xue , Jiang Kai , Ward Tarsha , Aikhionbare Felix , Guo Zhen , Forte John G. , Yao Xuebiao
Published: August 2007

Syntaxin and Munc18 are essential for regulated exocytosis in all eukaryotes. It was shown that Munc18 inhibition of neuronal syntaxin 1 can be overcome by CDK5 phosphorylation, indicating that structural change disrupts the syntaxin–Munc18 interaction. Here, we show that this phosphorylation promotes the assembly of Munc18b–syntaxin 3–SNAP25 tripartite complex and membrane fusion machinery SNARE. Using siRNAs to screen for genes required for regulated epithelial secretion, we identified the requirements of CDK5 and Munc18b in cAMP‐dependent gastric acid secretion. Biochemical characterization revealed that Munc18b bears a syntaxin 3‐selective binding site located at its most C‐terminal 53 amino acids. Significantly, the phosphorylation of Thr572 by CDK5 attenuates Munc18b–syntaxin 3 interaction and promotes formation of Munc18b–syntaxin 3–SNAP25 tripartite complex, leading to an assembly of functional Munc18b–syntaxin 3–SNAP25–VAMP2 membrane fusion machinery. Thus, our studies suggest a novel regulatory mechanism in which phosphorylation of Munc18b operates vesicle docking and fusion in regulated exocytosis.
Modulation of the protein environment in the hydrophilic pore of the ammonia transporter protein AmtB upon GlnK protein binding
Authors: Ishikita Hiroshi
Published: August 2007

The conduction of ammonia/ammonium () through the channel protein AmtB is inhibited by the binding of the signal transduction protein GlnK. In the AmtB–GlnK binding interface, there exists an binding site – Am6. The calculated pK
a values at the Am6 sites in both the AmtB–GlnK complex and isolated AmtB implies the dominance of an uncharged NH3 state. The GlnK protein binding causes a significant downshift in the Am6 pK
a value of the AmtB. However, this downshift is perfectly compensated by the reorientation of the protein backbone (carbonyl group of Cys312 from the AmtB part) upon AmtB–GlnK complex formation.
Activation of Candida rugosa lipase at alkane–aqueous interfaces: A molecular dynamics study
Authors: James Jayasundar Jayant , Lakshmi Baddireddi Subadhra , Seshasayee Aswin Sai Narain , Gautam Pennathur
Published: August 2007

The effect of solvent hydrophobicity on activation of Candida rugosa lipase (CRL) was investigated by performing molecular dynamics simulations for four nano seconds (ns). The closed/inactive conformer of CRL (PDB code 1TRH) was solvated in three alkane–aqueous environments. The alkanes aggregated in a predominantly aqueous environment and by 1 ns a stable spherical alkane–aqueous interface had formed. This led to the interfacial activation of CRL. On analyzing the simulated conformers with the closed conformer of CRL, the flap was found to have opened from a closed state by 7.7 Å, 10.2 Å, 13.1 Å at hexane–aqueous, octane–aqueous, and decane–aqueous interfaces. Further, essential dynamics analysis revealed that major anharmonic fluctuations were confined to residues 64–81, the flap of CRL.
Single exposure of human fibroblasts (WI‐38) to a sub‐cytotoxic dose of UVB induces premature senescence
Authors: Straface Elisabetta , Vona Rosa , Ascione Barbara , Matarrese Paola , Strudthoff Tiziana , Franconi Flavia , Malorni Walter
Published: August 2007

In this work, we present a new model of stress‐induced premature senescence obtained by exposing human fibroblasts (WI‐38) at early passages (passages 2–4) to a single sub‐cytotoxic dose of UVB (200 mJ/cm2). We show that this treatment leads to the appearance of several biomarkers of senescence such as enlarged and flattened cell morphology, the presence of nuclear heterochromatic foci and β‐galactosidase activity. Furthermore, we demonstrate that a mild ROS production and p53 activation are upstream events required for the induction of premature senescence. Our method represents an alternative in vitro model in photoaging research and could be used to test potential anti‐photoaging compounds.
Lysophosphatidylethanolamine stimulates chemotactic migration and cellular invasion in SK‐OV3 human ovarian cancer cells: Involvement of pertussis toxin‐sensitive G‐protein coupled receptor
Authors: Park Kyoung Sun , Lee Ha Young , Lee Sun Young , Kim Mi-Kyoung , Kim Sang Doo , Kim Jung Mo , Yun Jeanho , Im Dong-Soon , Bae Yoe-Sik
Published: August 2007

We investigated whether lysophosphatidylethanolamine (LPE) modulates cellular signaling in different cell types. SK‐OV3 ovarian cancer cells and OVCAR‐3 ovarian cancer cells were responsive to LPE. LPE‐stimulated intracellular calcium concentration ([Ca2+]i) increase was inhibited by U‐73122, suggesting that LPE stimulates calcium signaling via phospholipase C activation. Moreover, pertussis toxin (PTX) almost completely inhibited [Ca2+]i increase by LPE, indicating the involvement of PTX‐sensitive G‐proteins. Furthermore, we found that LPE stimulated chemotactic migration and cellular invasion in SK‐OV3 ovarian cancer cells. We examined the role of lysophosphatidic acid receptors on LPE‐stimulated cellular responses using HepG2 cells transfected with different LPA receptors, and found that LPE failed to stimulate nuclear factor kappa B‐driven luciferase. We suggest that LPE stimulates a membrane bound receptor, different from well known LPA receptors, resulting in chemotactic migration and cellular invasion in SK‐OV3 ovarian cancer cells.
A Nori but not a Konbu, dietary supplement decreases the cholesterolaemia, liver fat infiltration and mineral bioavailability in hypercholesterolaemic growing Wistar rats
Authors: Bocanegra Arancha , Nieto Ana , Bastida Sara , Benedí Juana , Sánchez-Muniz Francisco J.
Published: August 2007

The nutritional consequences of algae consumption in young populations consuming hypercholesterolaemic diets have hardly been investigated. This study tests the effect of algae supplementation of cholesterol-enriched balanced diets on growth, dietary efficiency ratio, mineral intake and absorption, organ weight and structure and cholesterolaemia in growing Wistar rats. Three groups of ten rats each were fed for 3 weeks with experimental diets containing 93 % casein-soyabean oil base with 2·4 % cholesterol-raising agent and 7 % supplement. The control group received cellulose (35 %), group 2 consumed Nori (33·8 % fibre) and group 3 consumed Konbu (36·1 % fibre). Food intake and body weight gain were not significantly affected. Algae groups presented significantly higher dietary efficiency ratio values than control rats. Apparent absorption of several minerals appeared significantly affected, mainly in Nori-fed rats, with a significant decrease in the ratio of Zn and Cu intakes and apparent absorption. Nori diet significantly decreased plasma cholesterol. Algae supplement did not significantly affect organ size and structure. Control and Konbu rats showed severe liver fat infiltration, while Nori rats exhibited a significantly lower degree of lipid-like hepatocyte vacuolization but light to moderate leukocyte infiltration. Light to moderate scaling off of the epithelium and moderate submucosa oedema was observed in all groups. Although long-term studies are needed to check the possible extrapolation of these data to human subjects, it can be concluded that a Nori, but not a Konbu, dietary supplement reverses the negative effect of dietary cholesterol intake and also appears to be related to mineral availability in growing subjects.
Temperature differences in the air layer close to a road surface
Authors: Bogren Jörgen , Gustavsson Torbjörn , Karlsson Maria
Published: August 2007

In this study, profiles of temperature and humidity (<250 cm above the road and 5 m into the surroundings) have been used to examine the development of temperature differences in the air layer close to the road. Temperature, humidity and wind profiles were measured, together with net radiation and observations of road surface state, at a test site at Road 45, Surte, Sweden. Measured temperature differences were compared with present weather, preceding weather, surface status, wind direction and other parameters thought to be important for the development of temperature differences. The results showed that large temperature differences (1–3°C between 250 cm and 10 cm above the road) occurred when there was a high risk of slipperiness caused by hoarfrost, snow or ice on the road. The temperature differences between different levels were associated with the exchange of humidity and temperature between the air layer and the road surface. The 10 cm level reflected the surface processes well. Higher levels were influenced by the surroundings because of turbulence and advection. This study emphasises the need for measurements to be taken at a height and place that reflects the processes at the road surface. Copyright © 2001 Royal Meteorological Society
Adjustment time for road surface temperature during weather changes
Authors: Postgård U
Published: August 2007

The object of this study is to examine the possibility of developing a model that can determine road surface adjustment times to new conditions after weather changes. Situations where the weather changes from clear to overcast conditions are studied in order to produce a worst‐case scenario. One hypothesis tested is that the decrease in road surface temperature (RST) differences between shaded and sun‐exposed stations on clear days can be used to determine the reduction in RST difference on days with weather changes. A relationship that describes the variation in RST difference as a function of time of day and season is developed. For clear days a fourth‐order polynomial can describe the relationship between RST differences and time of day. The coefficient in the polynomial depends on maximal solar elevation. Validation of the model for clear days showed that the deviation between modelled and measured values varied between 0.3 and$0.5\ ^{\circ}\hbox{C}$. It was also possible to use the clear day relationship to predict the decrease in RST differences for situations with weather changes, but during these situations the deviations between modelled and measured values were higher and also tended to show a positive bias. Copyright © 2001 Royal Meteorological Society
An early freeze in southern Brazil in April 1999 and its NWP guidance
Authors: Satyamurty Prakki , Fonseca Josiane Ferreira Bustamante , Bottino Marcus Jorge , Seluchi Marcelo E , Lourenço Maria Cristina Maciel , Gonçalves Luis Gustavo Gonçalves de
Published: August 2007

A cold air outbreak occurred in the third week of April 1999 in southern Brazil. A synoptic study of this rare event is undertaken. A surface high pressure cell in the Pacific Ocean off the coast of Chile slowly built up and moved eastward on 14 April. It started crossing the Andes, acquiring the characteristic shape of a bean on 15th, and separated into two cells later in the day. The cell on the lee side of the mountains moved gradually northwards over central South America affecting northern Argentina, Paraguay, Uruguay, Bolivia and southern Brazil. The temperature fell $15 \ ^{\circ}\hbox{C}$ in the state of Mato Grosso (about $15 \ ^{\circ}\hbox{S}$). In southern Brazil temperatures below freezing were registered in some places on the 17th and 18th and frost occurred in many states. There was snowfall in the uplands of Santa Catarina on the 17th, and such an early snow had not been recorded for 30 years. Baroclinic synoptic wave intensification followed by surface low development in association with a cut‐off low formation in the middle and upper troposphere were responsible for strong surface southerlies over Argentina on the 16th and 17th. Cold air advection by the southerlies in the eastern sector of the high‐pressure centre was responsible for the northward projection of the high pressure cell east of the Andes. The whole event was well predicted by the Centro de Previsão de Tempo e Estudos Climáticos/Instituto Nacional de Pesquisas Espaciais (CPTEC/INPE) operational global and regional models with lead times of 120 and 60 hours respectively. Copyright © 2002 Royal Meteorological Society.
FLEXIBLE FUNCTIONAL FORMS, CURVATURE CONDITIONS, AND THE DEMAND FOR ASSETS
Authors: SERLETIS APOSTOLOS , SHAHMORADI ASGHAR
Published: August 2007

This paper focuses on the demand for money in the United States in the context of five popular locally flexible functional forms—the generalized Leontief, the basic translog, the almost ideal demand system, the Minflex Laurent, and the normalized quadratic reciprocal indirect utility function. We pay explicit attention to the theoretical regularity conditions of positivity, monotonicity, and curvature and argue that much of the older empirical literature ignores economic regularity. We treat the curvature property as a maintained hypothesis and provide a comparison in terms of violations of the regularity conditions and in terms of output in the form of a full set of elasticities. We also provide a policy perspective, in that a strong case can be made for abandoning the simple sum approach to monetary aggregation, on the basis of the low elasticities of substitution among the components of the popular M2 aggregate of money.
CAUTION OR ACTIVISM? MONETARY POLICY STRATEGIES IN AN OPEN ECONOMY
Authors: ELLISON MARTIN , SARNO LUCIO , VILMUNEN JOUKO
Published: August 2007

We examine optimal policy in an open-economy model with uncertainty and learning, where monetary policy actions affect the economy through the real exchange rate channel. Our results show that the degree of caution or activism in optimal policy depends on whether central banks are in coordinated or uncoordinated equilibrium. If central banks coordinate their policy actions then activism is optimal. In contrast, if there is no coordination, caution prevails. In the latter case caution is optimal because it helps central banks to avoid exposing themselves to manipulative actions by other central banks.
Temporal variation in Sr and 87Sr/86Sr of the Brahmaputra: Implications for annual fluxes and tracking flash floods through chemical and isotope composition
Authors: Rai Santosh K. , Singh Sunil K.
Published: August 2007

Temporal variations in dissolved Sr and its 87Sr/86Sr in the Brahmaputra River were determined for the first time by analyzing biweekly samples collected over a period of about a year at Guwahati. Sr in the Brahmaputra range from 0.604 to 1.392 μM with 87Sr/86Sr of 0.71594 to 0.71802. Sr concentration decreases in monsoon (except for the 15 June 2000 sample, which had anomalously high concentrations of Sr and major ions) compared to the nonmonsoon period. The decrease in elemental abundances, a factor of ∼2, is not proportional to the increase in discharge, an order of magnitude, indicating enhanced weathering during monsoon. This can be a cumulative effect of an increase in drainage area and in physical weathering during monsoon. 87Sr/86Sr and other proxies of silicate weathering show a relatively lower contribution from silicate weathering to the major ion and Sr budget during monsoon with a concomitant increase in carbonate weathering contribution. Shorter interaction time between water and minerals during monsoon coupled with the slower weathering kinetics of silicate compared to carbonate can be contributing factors to the seasonal changes in their relative contributions to the major ion budget. This study shows that the annual fluxes of various ions, ΣCatsil, and Srsil calculated on the basis of measured biweekly concentrations and monthly water discharge data are roughly within ±35% of those calculated using either the lowest or the highest concentrations and annual water discharge. This implies that a tropical region such as in India, where river discharge is governed mostly by monsoon rains, the annual elemental fluxes measured during monsoon would be a good approximation for their discharge weighted annual fluxes; however, an additional sampling during a drier period would be required to understand the weathering processes. The geochemistry of the 15 June 2000 sample is anomalous. The chemistry of this sample is similar to those from the Tibetan region, an inference consistent with reports of a flash flood in the Brahmaputra due to a natural dam burst in the Yigong River of Tibet. These results highlight the use of the chemical and isotopic composition of water samples to track and quantify the source and discharge of a flash flood.
Ice polar stratospheric clouds detected from assimilation of Atmospheric Infrared Sounder data
Authors: Stajner Ivanka , Benson Craig , Liu Hui‐Chun , Pawson Steven , Brubaker Nicole , Chang Lang‐Ping , Riishojgaard Lars Peter , Todling Ricardo
Published: August 2007

A novel technique is presented for the detection and mapping of ice polar stratospheric clouds (PSCs), using brightness temperatures from the Atmospheric Infrared Sounder (AIRS) “moisture” channel near 6.79 μm. It is based on observed‐minus‐forecast residuals (O‐Fs) computed when using AIRS radiances in the Goddard Earth Observing System version 5 (GEOS‐5) data assimilation system. Brightness temperatures are computed from six‐hour GEOS‐5 forecasts using a radiation transfer module under clear‐sky conditions, meaning they will be too high when ice PSCs are present. We study whether the O‐Fs contain quantitative information about PSCs by comparison with sparse data from the Polar Ozone and Aerosol Measurement (POAM) III solar occultation instrument. AIRS O‐Fs lower than −2 K generally coincide with PSCs observed by POAM III. Synoptic maps of AIRS O‐Fs lower than −2 K are constructed as a proxy for ice PSCs. These are used to investigate spatio‐temporal variations of Antarctic PSCs in the year 2004.
Potential climatic effects of meteoric smoke in the Earth's paleo‐atmosphere
Authors: Saunders Russell W. , Forster Piers M. , Plane John M. C.
Published: August 2007

Modelling of the growth of meteoric smoke in the Earth's atmosphere, by assuming the formation of either simple spherical (compact) particles or, more realistically, fractal (porous) aggregates, highlights important differences in the predicted atmospheric size distributions as a function of altitude. The calculated UV extinction and direct radiative forcing (DRF) of these types of particles is also quite different. It is shown that, with regard to (a), forming a UV barrier before the presence of significant ozone levels in the atmosphere and (b), triggering ‘snowball Earth’ glaciations by negative DRF, fractal smoke particles are unlikely to have been important even if the flux of interplanetary dust into the atmosphere was 3 orders of magnitude higher than the present day. However, if these particles are effective ice nuclei, then subsequent indirect forcing through ice cloud formation could have made a more significant contribution to the onset of ancient glaciation episodes.
On the cause of IMF By related mid‐ and low latitude magnetic disturbances
Authors: Vennerstrom S. , Christiansen F. , Olsen N. , Moretto T.
Published: August 2007

An analysis of the effect of the IMF By on near‐Earth low and mid‐latitude magnetic disturbances is presented. In particular the contribution from field‐aligned currents (FACs) connected to the polar regions is investigated. Based on statistically determined high‐latitude FAC patterns for various Interplanetary Magnetic Field (IMF) directions, we estimate the FAC contribution to the mid‐ and low latitude magnetic disturbance and its dependence on the IMF. The estimated perturbations are compared with observations from the ground and from the low‐altitude polar orbiting satellite Oersted. It is found that the long‐distance effect of the high‐latitude FACs constitute the major source to IMF By and Bz related magnetic east‐west disturbances at mid‐ and low latitudes.
Thermal demagnetization of Martian upper crust by magma intrusion
Authors: Ogawa Yoshiko , Manga Michael
Published: August 2007

The absent or weak magnetic field above large Martian volcanoes may provide constraints on their formation and the carrier of magnetization. We consider the ability of magma intrusions to thermally demagnetize the shallow crust beneath volcanoes through heat conduction and hydrothermal circulation. If magnetization is dominated by magnetite, the volume of crust that is thermally demagnetized is similar to the volume of crust emplaced since the dynamo field disappeared. If magnetization is dominated by pyrrhotite, the volume of crust that is demagnetized is typically more than twice the volume of magma intruded. Hydrothermal circulation contributes negligible additional thermal demagnetization, beyond that from heat conduction alone, for permeabilities less than O(10−15) m2.
Biological characterization of citrus tristeza virus isolates by in vitro tissue cultures
Authors: Ghorbel R. , Navarro L. , Duran‐Vila N.
Published: August 2007

Stem segments from Mexican lime, sweet orange, grapefruit, Citrus excelsa and alemow, infected with five citrus tristeza virus (CTV) isolates, were cultured in vitro. Regeneration of roots and shoots were modified as a result of infection. The effect of CTV on the morphogenesis of stem segments cultured in vitro depended on the CTV isolate and the plant host, and showed a correlation with the in vivo effects observed in biological indexing. Evaluation of the morphogenic response of stem segments of Mexican lime and grapefruit can be used as an additional tool for the biological characterization of CTV isolates. The symptoms on sweet orange plants obtained from regenerated shoots indicated that CTV is unevenly distributed in the host plant cells and that the regeneration process may be utilized as a tool to separate strains from complex field isolates.
Effects of bean line pattern mosaic virus on the monocyclic components of rust and angular leaf spot of Phaseolus bean at different temperatures
Authors: Bassanezi R. B. , Amorim L. , Bergamin Filho A. , Hau B.
Published: August 2007

Monocyclic components (development rate during the incubation period or latent period, lesion density, lesion size and disease severity) of rust (Uromyces appendiculatus) and of angular leaf spot (Phaeoisariopsis griseola) in two bean (Phaseolus vulgaris) cultivars (Rosinha G‐2 and Carioca), pre‐infected or not with bean line pattern mosaic virus (BLPMV), were determined. Trials were conducted at temperatures in the range from 9 to 27°C for rust and from 12 to 30°C for angular leaf spot. Regardless of viral pre‐infection, the effect of temperature on the four monocyclic components followed an optimum curve and could be described by a generalized beta function. Generally, angular leaf spot was favoured by higher temperatures with an optimum for disease severity between 24.2 and 28.3°C compared with 15.9–18.5°C for rust. Pre‐infection with BLPMV did not change the shape of the optimum curves for all components, but significantly reduced lesion density and disease severity on both cultivars. The development rates during incubation and latent periods for both fungal diseases were not affected by BLPMV. Pre‐infection with virus did not alter the ranking of cultivars with respect to resistance to both fungal diseases.
Effects of wind, relative humidity, leaf movement and colony age on dispersal of conidia of Uncinula necator, causal agent of grape powdery mildew
Authors: Willocquet L. , Berud F. , Raoux L. , Clerjeau M.
Published: August 2007

A wind tunnel was designed to study the effect of wind, relative humidity, leaf movement and colony age on dispersal of conidia of Uncinula necator. Wind speed as low as 2.3 m s−1 instantaneously triggered dispersal of conidia from fixed leaf discs of 18‐day‐old infections. Conidia were observed on sporulating leaf discs even after exposure to 17 m s−1 wind. The fraction of conidia dispersed at a given wind speed increased with colony age from 12 to 24 days. Conidia of 27‐day‐old colonies were less easily dispersed. No gradient of maturation of conidia along the conidial chain was observed, suggesting that even newly formed conidia were able to germinate after dispersal. Germination of dispersed conidia decreased slightly with greater colony age. Both wind and simulated rain drops caused dispersal of conidia from infected leaves. Leaf movement at wind speed of 3.5–4 m s−1 increased dispersal, and the first impact of three simulated raindrops caused release of 53% of the total conidia dispersed. Relative humidity had no effect on dispersal of conidia at different wind speeds.
Use of a scanning electron microscope to pattern large areas of a hydrogen resist for electrical contacts
Authors: Hallam T. , Butcher M. J. , Goh K. E. J. , Ruess F. J. , Simmons M. Y.
Published: August 2007

We use scanning tunneling microscopy to investigate the atomic-scale process of hydrogen desorption from H:Si(001) with a 25keV scanning electron microscope (SEM) electron beam and characterize the rate of desorption, contaminant deposition, and desorption straggle. We then demonstrate the effectiveness of a SEM to pattern a hydrogen resist for device fabrication by showing that it is compatible with phosphine (PH3) dosing to form large (4×4μm2) buried planar conducting regions in silicon.
Critical state in low-dimensional superconductors with an edge barrier
Authors: Ainbinder R. M. , Maksimov I. L.
Published: August 2007

The combined influence of the surface barrier and the bulk pinning on the shape of the magnetization curve and the curves of the harmonics of the magnetic susceptibility is investigated for a slab in a parallel magnetic field. The change in shape of these curves and the characteristic differences in the behavior of several harmonics is described with both these mechanisms of irreversibility taken into account. An effect observed in thin films—a change in sign of the imaginary part of the third Fourier harmonic of the magnetic susceptibility upon a change of the dominant mechanism of irreversibility—is confirmed.
Nonclassical magnetic dynamics and negative exchange bias in Nd0.5Sr0.5MnO3 films
Authors: Prokhorov V. G. , Kaminsky G. G. , Komashko V. A. , Lee Y. P. , Park S. Y. , Hyun Y. H. , Kim J. B. , Park J. S. , Svetchnikov V. L. , Pashchenko V. P. , Khokhlov V. A.
Published: August 2007

Amorphous, nanocluster, and self-organizing bilayer Nd0.5Sr0.5MnO3 films are prepared by rf magnetron sputtering. The amorphous film turns out to be a typical paramagnet with free motion of the individual Mn spins, the magnetic properties of which are well described by the Curie-Weiss approximation. The nanocluster film manifests magnetic properties mimicking superparamagnetic particles with a nonclassical magnetic dynamics. The unique shape of the hysteresis loops, which have hysteretic lobes at high magnetic field but are nonhysteretic as the field crosses zero, suggests that each particle (nanocluster) is a closure magnetic domain (or magnetic vortex) rather than a single domian. At the same time, a blocked to unblocked transition was observed with increasing temperature, as in the usual superparamagnet. The self-organizing bilayer film demonstrates a negative exchange bias, which is typical for the ferromagnet/antiferromagnet hybrid system in spite of the fact that both layers in our case have a ferromagnetic origin. The magnetic properties of the films are discussed in detail on the basis of modern theoretical models.
IR spectra of water polyaggregates in a nitrogen cryomatrix
Authors: Drobyshev A. , Abdykalykov K. , Aldiyarov A. , Kurnosov V. , Tokmoldin N. , Zhumagaliuly D.
Published: August 2007

An attempt is undertaken to determine qualitatively, using the cryomatrix isolation method, the state of water cryocondensates in accordance with their cluster composition. To this end IR spectrometry is performed on thin cryovacuum condensate films formed from a mixture of water vapor and nitrogen in a combined condensation regime at substrate temperature T=16K. The water content in nitrogen in most experiments was 5%. The water partial pressure in the course of the experiments and the film thicknesses were determined in a way so that it would be possible to compare them with pure water films with the same reduced thickness grown at the same pressure and temperature. As a result of comparing our IR spectra with the data obtained by other authors it was concluded that water polyaggregates (H2O)n with different composition are formed in the process of combined condensation of water and nitrogen. In the concentration range studied, a large fraction of the polyaggregates consisted of dimers, and higher-order polyaggregates, right up to hexamers, were also present. In addition, the presence of a strong absorption band in the frequency range of librational vibrations is due to the presence of water microcrystallites in the nitrogen matrix. The presumed cyclical character of cluster formation made it possible to consider the clusters to be the nuclei of a crystalline phase. The short-range order parameters in the polyaggregates and microcrystallites formed can largely determine the character of the thermally stimulated polyamorphic and polymorphic transformations in amorphous solid water.
Structural phase transition in two-dimensional tetramer-cuprate Na5RbCu4(AsO4)4Cl2
Authors: Gnezdilov V. , Bedarev V. , Gnatchenko S. , Pashchenko M. , Pashkevich Yu. , Lemmens P. , Zvyagin S. , Mo X. , Queen W. , Hwu S.-J.
Published: August 2007

Raman scattering and optical birefringence are used in to investigate a low-temperature phase transition in a single crystal of the two-dimensional Na5RbCu4(AsO4)4Cl2. Phonon anomalies point to a first-order nature of the transition. The observed transition is most probably related to an order-disorder transition of the Rb ion positions along the z axis within the ionic framework of mixed alkali metal chloride lattices.
O
O
C
O
+
cation I: Characterization of its isomers and lowest electronic states
Authors: Ndome H. , Alcaraz C. , Hochlaf M.
Published: August 2007

Accurate ab initio calculations are performed in order to investigate the stable isomers of OOCO+ and its electronic states at both the molecular and asymptotic regions. These calculations are done using large basis sets and configuration interaction methods. Our theoretical computations predict the presence of four stable forms: A global minimum where a weakly bound charge transfer complex (OOOC+) may be found. Few tenths of cm−1 above in energy, the OOCO+ very weakly bound isomer is predicted. At 1.75eV above OOCO+, a strongly bound centrosymmetric isomer (c-CO3+) is located. For energies >8eV, a third isomer of C2v symmetry is found where one oxygen is in the center. The one-dimensional potential energy surface cuts of these electronic states reveal the existence of shallow potential wells for OOCO+ and OOOC+ and of deep potential wells for the two other forms, where electronically excited molecules can be formed at least transiently. Finally, the electronic states of each isomer should interact by spin-orbit, vibronic, Renner-Teller, and Jahn-Teller couplings in competition with isomerization processes converting one form to another.
Photofragment slice imaging studies of pyrrole and the Xe⋯pyrrole cluster
Authors: Rubio-Lago L. , Zaouris D. , Sakellariou Y. , Sofikitis D. , Kitsopoulos T. N. , Wang F. , Yang X. , Cronin B. , Devine A. L. , King G. A. , Nix M. G. D. , Ashfold M. N. R. , Xantheas S. S.
Published: August 2007

The photolysis of pyrrole has been studied in a molecular beam at wavelengths of 250, 240, and 193.3nm, using two different carrier gases, He and Xe. A broad bimodal distribution of H-atom fragment velocities has been observed at all wavelengths. Near threshold at both 240 and 250nm, sharp features have been observed in the fast part of the H-atom distribution. Under appropriate molecular beam conditions, the entire H-atom loss signal from the photolysis of pyrrole at both 240 and 250nm (including the sharp features) disappear when using Xe as opposed to He as the carrier gas. We attribute this phenomenon to cluster formation between Xe and pyrrole, and this assumption is supported by the observation of resonance enhanced multiphoton ionization spectra for the (Xe⋯pyrrole) cluster followed by photofragmentation of the nascent cation cluster. Ab initio calculations are presented for the ground states of the neutral and cationic (Xe⋯pyrrole) clusters as a means of understanding their structural and energetic properties.