bluuebunny/crossref_metadata_2025 huggingface dataset:
Bulk organic δ13C and C/N ratios as palaeosalinity indicators within a Scottish isolation basin
Authors: Mackie Elizabeth A. V. , Leng Melanie J. , Lloyd Jeremy M. , Arrowsmith Carol
Published: June 2005

Microfossils in isolation basin sediments are frequently used to reconstruct sea‐level change, but preservation problems and non‐analogue situations can limit their usefulness. Here we investigate the potential of stable carbon isotopes (δ13C) and C/N ratios from bulk organic matter, as an alternative proxy of salinity within isolation basin sediments from a basin in northwest Scotland. Within the Holocene sediment δ13C and C/N are determined largely by the mean weighted values of the predominant source of the organic material. Analysis of modern materials and comparison with the diatom record shows that the marine parts of the sequence are dominated by high δ13C and variable C/N. In the fresh water sequences the organic material is a mixture of both freshwater aquatic and terrestrial plant input that have relatively low δ13C and high C/N. The application of δ13C and C/N ratios in the studied basin in general follow the environmental change recorded by the diatoms and shows the potential of bulk organic matter in the investigation of salinity change in isolation basins. Copyright © 2005 John Wiley & Sons, Ltd.
Holocene millennial/centennial‐scale multiproxy cyclicity in temperate eastern Australian estuary sediments
Authors: Skilbeck C. Gregory , Rolph Timothy C. , Hill Natalie , Woods Jonathan , Wilkens Roy H.
Published: June 2005

We have undertaken a comparative study of down‐core variation in multiproxy palaeoclimate data (magnetic susceptibility, calcium carbonate content and total organic carbon) from two coastal water bodies (Myall and Tuggerah Lakes) in temperate eastern Australia to identify local, regional and global‐forcing factors within Holocene estuarine sediments. The two lakes lie within the same temperate climate zone adjacent to the Tasman Sea, but are not part of the same catchment and drain different geological provinces. One is essentially a freshwater coastal lake whereas the other is a brackish back‐barrier lagoon. Despite these differences, data from two sites in each of the two lakes have allowed us to investigate and compare cyclicity in otherwise uniform, single facies sediments within the frequency range of 200–2000 years, limited by the sedimentation rate within the lakes and our sample requirements. We have auto‐ and cross‐correlated strong periodicities at ∼360 years, ∼500–530 years, ∼270–290 years, 420–450 years and ∼210 years, and subordinate periods of ∼650 years, 1200–1400 years and ∼1800 years. Our thesis is that climate is the only regionally available mechanism available to control common millennial and centennial scale cyclicity in these sediments, given the geographical and other differences. However, regional climate may not be the dominant effect at any single time and either location. Within the range of frequency spectral peaks we have identified, several fall within known long‐term periodical fluctuations of sun spot activity; however, feedback loops associated with short‐term orbital variation, such as Dansgaard–Oeschger cycles, and the relationship between these and palaeo‐ENSO variation, are also possible contributors. Copyright © 2005 John Wiley & Sons, Ltd.
Climate change in lowland Central America during the late deglacial and early Holocene
Authors: Hillesheim Michael B. , Hodell David A. , Leyden Barbara W. , Brenner Mark , Curtis Jason H. , Anselmetti Flavio S. , Ariztegui Daniel , Buck David G. , Guilderson Thomas P. , Rosenmeier Michael F. , Schnurrenberger Douglas W.
Published: June 2005

The transition from arid glacial to moist early Holocene conditions represented a profound change in northern lowland Neotropical climate. Here we report a detailed record of changes in moisture availability during the latter part of this transition (∼11 250 to 7500 cal. yr BP) inferred from sediment cores retrieved in Lake Petén Itzá, northern Guatemala. Pollen assemblages demonstrate that a mesic forest had been largely established by ∼11 250 cal. yr BP, but sediment properties indicate that lake level was more than 35 m below modern stage. From 11 250 to 10 350 cal. yr BP, during the Preboreal period, lithologic changes in sediments from deep‐water cores (>50 m below modern water level) indicate several wet–dry cycles that suggest distinct changes in effective moisture. Four dry events (designated PBE1‐4) occurred centred at 11 200, 10 900, 10 700 and 10 400 cal. yr BP and correlate with similar variability observed in the Cariaco Basin titanium record and glacial meltwater pulses into the Gulf of Mexico. After 10 350 cal. yr BP, multiple sediment proxies suggest a shift to a more persistently moist early Holocene climate. Comparison of results from Lake Petén Itzá with other records from the circum‐Caribbean demonstrates a coherent climate response during the entire span of our record. Furthermore, lowland Neotropical climate during the late deglacial and early Holocene period appears to be tightly linked to climate change in the high‐latitude North Atlantic. We speculate that the observed changes in lowland Neotropical precipitation were related to the intensity of the annual cycle and associated displacements in the mean latitudinal position of the Intertropical Convergence Zone and Azores–Bermuda high‐pressure system. This mechanism operated on millennial‐to‐submillennial timescales and may have responded to changes in solar radiation, glacial meltwater, North Atlantic sea ice, and the Atlantic meridional overturning circulation (MOC). Copyright © 2005 John Wiley & Sons, Ltd.
Isolation of obligate anaerobic rumen bacteria capable of degrading the neurotoxin β‐ODAP (β‐N‐oxalyl‐L‐α,β‐diaminopropionic acid) as evaluated by a liquid chromatography/biosensor analysis system
Authors: Marichamy Sankar , Yigzaw Yirgalem , Gorton Lo , Mattiasson Bo
Published: June 2005

Six pure strains of obligate anaerobes capable of degrading the toxin β‐N‐oxalyl‐L‐α, β‐diaminopropionic acid (β‐ODAP) contained in grass pea (Lathyrus sativus) have been isolated from cow rumen. The new isolates were identified as Megasphaera elsdenii (five different genotypes) and Clostridium bifermentans using 16S rDNA analysis. The β‐ODAP degrading efficiency of the isolates was evaluated by measuring the amount of β‐ODAP in the growth medium, which contained β‐ODAP as the only carbon source, before and after incubation with the microbes. The method of analysis was liquid chromatography employing bioelectrochemical detection. The biosensor is based on co‐immobilising two enzymes, glutamate oxidase (GlOx) and horseradish peroxidase (HRP), on the end of a spectrographic graphite electrode. β‐ODAP is oxidised by GlOx to form H2O2, which in turn is bioelectrocatalytically reduced by HRP through a mediated reaction using a polymeric mediator incorporating Os2 + /3+ functionalities rapidly shuttling electrons with the electrode_giving rise to the analytical signal. On the basis of this analysis system, the new isolates are capable of utilising β‐ODAP as sole carbon source to a maximum of 90–95% within 5 days with concomitant increase in cell protein. Copyright © 2005 Society of Chemical Industry
Terpene profiles in Cantal and Saint‐Nectaire‐type cheese made from raw or pasteurised milk
Authors: Cornu Agnès , Kondjoyan Nathalie , Martin Bruno , Verdier‐Metz Isabelle , Pradel Philippe , Berdagué Jean‐Louis , Coulon Jean‐Baptiste
Published: June 2005

Terpene profiles in cheese can be considered a ‘terroir’ fingerprint as the information contained in it should enable the pastures on which the animals were fed to be recognised. Yet a certain elasticity of the signature must be taken into account when determining authentication strategies, since products acknowledged as containing a common signature may have undergone certain procedures, such as cheese making and milk pasteurisation, that could have potentially altered their terpene profiles. In this study, Cantal and Saint‐Nectaire‐type cheeses were made from both raw and pasteurised milk from the same herd of dairy cows that had been grazed on natural grassland. Cheeses from raw and pasteurised milk were made from the same milking on the same days. Cantal and Saint‐Nectaire‐type cheeses were made on 4 different days, alternatively over four weeks. The terpenes in the cheese fat were analysed by dynamic headspace/gas chromatography/mass spectrometry. A great diversity of monoterpenes, sesquiterpenes and oxygen‐containing derivatives were identified. The major terpenes identified in most cheeses were β‐caryophyllene, α‐ and β‐pinene and limonene. Milk pasteurisation did not induce changes in the terpene profile of the cheese. Significant differences (p < 0.001) were observed between Cantal and Saint‐Nectaire cheeses: α‐pinene, β‐myrcene and β‐phellandrene were, respectively, three, five and five times more abundant in Cantal cheese, while tricyclene, α‐phellandrene and geraniol were found exclusively in Cantal cheese. In contrast, unidentified sesquiterpenes with retention indices (KI) = 1342 and 1511, α‐cubebene, longifolene and γ‐elemene were more abundant or exclusively found in Saint‐Nectaire cheese. A significant relationship with the date of milking (p < 0.01) was observed for α‐pinene and tricyclene in Cantal, for β‐myrcene, δ‐3‐carene, p‐cymene and α‐terpinene in Saint‐Nectaire cheese. Copyright © 2005 Society of Chemical Industry
Roasting effects on fatty acid distribution of triacylglycerols and phospholipids in the kernels of pumpkin (Cucurbita spp) seeds
Authors: Yoshida Hiromi , Tomiyama Yuka , Kita Sayaka , Mizushina Yoshiyuki
Published: June 2005

In this study, changes in fatty acid distributions of pumpkin seeds (Cucurbita spp) in the course of the roasting process were investigated. Whole pumpkin seeds were exposed to microwaves for 6, 12, 20 or 30 min at a frequency of 2450 MHz. The kernels were separated from the seeds, and the lipid components and the fatty acid distributions of triacylglycerols (TAGs) and phospholipids (PLs) were analysed by a combination of thin layer chromatography and gas chromatography. Major lipid components were TAGs, free fatty acids (FFAs) and PLs, while steryl esters and diacylglycerols were also present in minor proportions. The greatest PL losses (p < 0.05) were observed in phosphatidyl ethanolamine, followed by phosphatidyl choline or phosphatidyl inositol. With a few exceptions, significant differences (p < 0.05) in fatty acid distributions occurred when the seeds were microwaved for 20 min or more. Nevertheless, the positional characteristics of fatty acid distributions in the TAGs were still retained after 20 min of roasting: unsaturated fatty acids were predominantly concentrated in the sn‐2‐position, and saturated fatty acids primarly occupied the sn‐1‐ or sn‐3‐position. These results suggest that no significant changes in fatty acid distribution of TAGs and PLs would occur within 12 min of microwave roasting, thus ensuring that a good‐quality product would be obtained. Copyright © 2005 Society of Chemical Industry
The effect of drying, pressure and processing time on the quality of liquid‐smoked trout (Salmo gairdnerii) fillets
Authors: Siskos Ilias , Zotos Anastasios , Taylor KD Anthony
Published: June 2005

A new fish smoking process was applied using a combination of liquid smoke and steaming at pressures up to 1 bar above atmospheric. Processing yield, sensory analysis, instrumental colour measurement, available lysine and polynuclear aromatic hydrocarbons (PAHs) were estimated. The losses due to processing were quite reasonable (20.05 ± 4.9% to 23.58 ± 3.9%) and slightly influenced by the process. The fillets processed at 2 bar steam pressure, for 30, 45 or 60 min and previously dried were assessed as highly acceptable regarding their firmness, colour, flavour and acceptability by panellists. The destruction of available lysine was not very high (21.1 ± 8.4%) and it was dependent upon the process. Depending on the method used, very low (0.63–3.2ng g−1) amounts of PAHs were found and were also dependent upon the process. Copyright © 2005 Society of Chemical Industry
Improving wheat for bread and tortilla production by manipulating glutenin‐to‐gliadin ratio
Authors: Uthayakumaran Surjani , Lukow Odean M
Published: June 2005

Gluten, starch, water soluble material, and glutenin‐rich and gliadin‐rich proteins were extracted from three Canadian wheat cultivars representing the Canada Western Red Spring (CWRS) (cv Roblin), Canada Western Extra Strong (CWES) (cv Glenlea) and Canada Prairie Spring (CPS) (cv AC Crystal) classes having glutenin‐to‐gliadin (Glu:Gli) ratios of 0.70, 0.75 and 0.85 respectively, all giving the same high‐molecular‐weight glutenin subunit score (Glu‐1 score) of 10. The resulting fractions were reconstituted to produce 18 mixtures of flour components, representing all combinations of Glu:Gli ratio and protein content observed in the original three flours. Dough rheological properties and baking (bread and tortilla) performance were determined using small‐scale techniques. Within any of the cultivars, increasing the Glu:Gli ratio in a reconstituted dough system had significant effects on dough and end‐use properties, causing increases in mixograph development time (MDT), maximum resistance (Rmax), pan bread loaf volume, tortilla dough maximum resistance and cooked tortilla puncture force. The CWRS wheat Roblin, proved to be best suited for pan bread at higher protein content and higher Glu:Gli ratio, and also produced a high protein tortilla of large diameter at a Glu:Gli ratio of 0.70. The CPS flour, AC Crystal, was good for making tortillas at protein contents of 110–130 g kg−1 and at its original ratio of 0.85. The CWES wheat Glenlea, did not perform as well in bread or tortilla‐making but in its role as a blending wheat, altering the Glu:Gli ratio of Glenlea to 0.70 may have an advantage by lowering mixing time without compromising baking properties. Manipulating the Glu:Gli ratio may make a wheat cultivar suitable for a particular end‐product. For the Department of Agriculture and Agri‐Food, Government of Canada, © Minister of Public Works and Government Services Canada 2005. Published for SCI by John Wiley & Sons, Ltd.
Effects of low temperature blanching on texture, microstructure and rehydration capacity of carrots
Authors: Sanjuán Neus , Hernando Isabel , Lluch M Angeles , Mulet Antonio
Published: June 2005

The effect on quality of stepwise blanching (first 10 min at 65 °C, 50 min holding time, and 1 min at 95 °C) prior to drying of carrot slices was compared with conventional blanching (95 °C, 1 min). As quality parameters, rehydration capacity (effective diffusivity De, equilibrium moisture content We), texture (puncture test) and microstructure (SEM and Cryo‐SEM) were chosen. Non‐significant differences were found between the We of stepwise blanched samples and conventionally blanched ones, both values being similar to the moisture content of fresh carrots. De of conventional blanched carrots was higher than for stepwise blanched ones. Maximum force of stepwise blanched samples was higher than those of conventionally blanched ones and not significantly different from fresh carrots. Microstructural observations showed that stepwise blanching preserved cell to cell contacts better than conventional blanching; this fact was attributed to pectin‐methyl‐esterase activation at 65 °C, resulting in the differences in the maximum force between both treatments. Conventionally blanched samples tended to separate along their cell walls, forming voids among the phloem parenchyma cells. These voids would be filled with water during rehydration, thus showing the slightly higher We and the higher De for conventionally blanched carrots. Copyright © 2005 Society of Chemical Industry
Processing of rye bran influences both the fermentation of dietary fibre and the bioconversion of lignans by human faecal flora in vitro
Authors: Aura Anna‐Marja , Karppinen Sirpa , Virtanen Hannele , Forssell Pirkko , Heinonen Satu‐Maarit , Nurmi Tarja , Adlercreutz Herman , Poutanen Kaisa
Published: June 2005

Plant lignans are converted to mammalian forms, enterodiol and enterolactone, in the colon. Enhanced plasma or urinary enterolactone levels have been associated with lowered risk of cardiovascular diseases and breast cancer. Processed rye bran and its fractions were compared to ascertain the fermentation rates of fermentable carbohydrates and the bioconversion of lignans. Rye bran was extruded and treated with a food‐grade xylanase. Part of the xylanase‐treated rye bran was separated into a soluble rye bran extract and an insoluble residue, and a part of the xylanase‐treated rye bran was freeze‐dried without separation. All the samples were digested by pepsin and pancreatin and subsequently fermented with a human faecal inoculum in vitro. The consumption of carbohydrates, the productions of short‐chain fatty acids (SCFA), enterodiol and enterolactone were followed as a function of time. The soluble rye bran extract showed the fastest fermentation rate and the highest extent of fermentation determined as the consumption of neutral sugar residues (arabinose, xylose and glucose), the production of SCFA and the formation of enterodiol and enterolactone. Xylanase treatment enhanced the fermentation rate of extruded rye bran. An even a higher fermentation rate was observed for rye bran extract containing soluble carbohydrates. The amount of enterolactone precursors in rye seemed to be too low for enterolactone formation using an amount of substrate suitable for carbohydrate fermentation. However, xylanase treatment enhanced the availability of plant lignans from rye bran, as enterodiol formation was increased by the use of xylanase. Copyright © 2005 Society of Chemical Industry
Effects of fibre derived from passion fruit seed on the activities of ileum mucosal enzymes and colonic bacterial enzymes in hamsters
Authors: Chau Chi‐Fai , Huang Ya‐Ling , Chang Fang‐Yu
Published: June 2005

Passion fruit, a popular tropical fruit, produces a large quantity of edible seeds as agricultural byproducts after juice extraction. The defatted passion fruit seed (PFS) contained a high level of insoluble fibre (∼90%, w/w) of desirable characteristics and physicochemical properties. Cellulose, pectic substances and hemicellulose were the major structural polysaccharides of the PFS insoluble fibre. In this study, the influence of the PFS insoluble fibre on the activities of ileum mucosal enzymes and colonic bacterial enzymes was investigated. It was found that the incorporation of the PFS insoluble fibre into a fibre‐free diet at 5% level significantly (p < 0.05) enhanced the intestinal amylase activity (137%), reduced the caecal pH (6.22), decreased the caecal ammonia content (−38.6%) and faecal ammonia output (−21.2%), and also decreased the activities of β‐D‐glucosidase (−37.4%), β‐D‐glucuronidase (−52.9%), mucinase (−35.5%) and urease (−91.4%) in faeces. Our results suggested that PFS insoluble fibre might exert favourable effects on intestinal health. The fact that PFS insoluble fibre was more effective than cellulose in improving intestinal health suggested it could be exploited as a new functional ingredient to promote intestinal function and health. Copyright © 2005 Society of Chemical Industry
The enrichment of Asian noodles with fiber‐rich fractions derived from roller milling of hull‐less barley
Authors: Izydorczyk MS , Lagassé SL , Hatcher DW , Dexter JE , Rossnagel BG
Published: June 2005

Fiber‐rich fractions (FRF) derived from roller milling of waxy (W) and high amylose (HA) starch hull‐less barley genotypes were evaluated for suitability as functional ingredients in fresh and dried white salted (WSN) and fresh yellow alkaline (YAN) noodles. FRF‐W and FRF‐HA both contained over 300 g kg−1 dietary fiber, and over 200 g kg−1 of β‐glucans. Replacement of 250 g kg−1 Canada Prairie Spring White (cv AC Vista) wheat patent flour with the FRF posed no problems in noodle processing, although water absorption had to be substantially increased. All three noodle types enriched with the FRF were significantly darker and contained more brown specks than the wheat flour control noodles. The presence of the FRF reduced cooking time of fresh YAN and WSN by ∼50%. The addition of FRF improved cooked YAN texture, as evidenced by increased firmness and resistance to compression. FRF‐enriched fresh WSN were comparable to the wheat flour control noodles for those parameters, whereas enrichment of dry WSN by FRF imparted less firmness and less chewiness. FRF‐enriched fresh YAN and WSN offer consumer convenience due to shorter cooking time, improved nutritional quality and acceptable cooking quality. These features might make FRF‐enriched noodles sufficiently attractive to health‐conscious consumers to overcome the negative effects of color and appearance Copyright © 2005 Society of Chemical Industry
A novel method to realize multi-wavelength with phase-shifted FBG inscribed in PMF
Authors: Zhao Y-C , Xu X-F , Li Y , Shao Z , Gao J-Y
Published: June 2005

A novel grating is proposed to produce
multi-wavelength output with inscribing phase-shifted fiber
Bragg grating (FBG) in polarization-maintaining fiber (PMF). The
reflective spectrum of grating is analyzed by a transfer matrix
method. The effects of grating parameters on property of the
phase-shifted FBG in PMF are discussed. We find that optimistic
phase-shifted FBG in PMF with high reflective peaks, narrow
bandwidths and multi-wavelength is possible if the grating
parameters are properly selected.
Normal and anomalous averages for systems with
Bose-Einstein condensate
Authors: Yukalov V I , Yukalova E P
Published: June 2005

The comparative behaviour of normal and anomalous
averages as functions of momentum or energy, at different
temperatures, is analysed for systems with Bose-Einstein
condensate. Three qualitatively distinct temperature regions are
revealed: The critical region, where the absolute value of the
anomalous average, for the main energy range, is much smaller than
the normal average. The region of intermediate temperatures, where
the absolute values of the anomalous and normal averages are of
the same order. And the region of low temperatures, where the
absolute value of the anomalous average, for practically all
energies, becomes much larger than the normal average. This shows
the importance of the anomalous averages for the intermediate and,
especially, for low temperatures, where these anomalous averages
cannot be neglected.
1083 nm single frequency ytterbium doped fiber laser
Authors: Huang S , Feng Y , Dong J , Shirakawa A , Musha M , Ueda K
Published: June 2005

Single frequency 1083 nm ytterbium fiber laser was
demonstrated by introducing loop mirror filter and polarization
controller in linear laser cavity. The loop mirror with unpumped
ytterbium fiber as a narrow bandwidth filter discriminated and
selected laser longitudinal modes efficiently. Spatial hole
burning effect was restrained by adjusting polarization controller
appropriately. The laser linewidth was about 2 KHz. Output power
up to 14 mW were obtained under the launched pump power of 100 mW
at 976 nm, the corresponding optical-optical conversion efficiency
was 14%, the slope efficiency was 18%. The measurement of RIN
and power stability indicated the stable operation of the laser.
The economics of soil productivity: local, national and global perspectives
Authors: Knowler D. J.
Published: June 2005

Soil degradation is a mounting problem on many smallholder lands in developing countries. Economic analysis has been an important tool in addressing this problem, beginning with assessments of the financial attractiveness of investing in soil conservation works. Data compiled from 67 studies of the financial attractiveness of conservation technologies suggest that many can provide positive net returns at the farm level (64·2 per cent). While such studies have made a valuable contribution, economists have been exploring additional applications of economics to the problem, such as the development of new perspectives under the guise of ecological economics. As a result, this paper argues it is an opportune time to assess progress in the field of economic analysis of soil degradation and to consider the policy ramifications of this research. Key issues are grouped into farm‐level considerations, national policy linkages and global issues. A number of policy implications emerge. Clearly, devising effective incentives at the farm or community (collective action) level must be a priority. As part of this effort, even more attention should be paid to the influence of macroeconomic and sectoral policies on soil productivity. Since soil degradation is also a problem with global ramifications, there is a clear rationale for intervention at the international level via mechanisms such as international transfers. Copyright © 2004 John Wiley & Sons, Ltd.
The Nucleating Effect of Carbon Nanotubes on Crystallinity in R‐BAPB‐Type Thermoplastic Polyimide
Authors: Yudin Vladimir E. , Svetlichnyi Valentine M. , Shumakov Alexander N. , Letenko Dmitriy G. , Feldman Alexander Y. , Marom Gad
Published: June 2005

Summary: The relatively high degree of crystallinity of a new thermoplastic polyimide (PI) makes it a favorable matrix candidate for fiber reinforced composites. This advantage is the result of the ability of the matrix to recrystallize during the composite manufacturing process. In this study we examine the potential nucleating effect of carbon nanotubes on a thermoplastic PI. In addition to their inherent mechanical contribution, the carbon nanotubes help recover a significant proportion of the original crystallinity.

Scanning electron micrograph of the spherulitic structure of a recrystallized carbon nanotube/polyimide film.

magnified image

Scanning electron micrograph of the spherulitic structure of a recrystallized carbon nanotube/polyimide film.
Cover Picture: Macromol. Theory Simul. 5/2005
Authors: Karssenberg Frederik G. , Piel Christian , Hopf Andreas , Mathot Vincent B. F. , Kaminsky Walter
Published: June 2005

Cover: The modeled 0th (black), 1st (green), 2nd (red) and 3rd (blue) order Markov and experimental copolymer composition of a series of ethylene‐propylene copolymers produced by the [(3‐MePh)(4‐MePh)C(2,7‐di‐tert‐BuFlu)(Cp)]ZrCl2 metallocene catalyst (top right). Schematical picture of the copolymerization of ethene (E) and propene (P), E‐E‐E‐E‐E‐E‐E‐E‐P‐P‐catalyst (inset). The way to decide upon the optimal Markov order for a 99.5% reliability on the basis of the chi‐square (χ2) value of the fitting of experimental and modeled 13C NMR spectra (bottom left). Further details can be found in the Communication by F. G. Karssenberg, C. Piel, A. Hopf, V. B. F. Mathot,* and W. Kaminsky on page 295.
Loss of heterozygosity and transcriptome analyses of a 1.2 Mb candidate ovarian cancer tumor suppressor locus region at 17q25.1‐q25.2
Authors: Presneau Nadège , Dewar Ken , Forgetta Vince , Provencher Diane , Mes‐Masson Anne‐Marie , Tonin Patricia N.
Published: June 2005

Loss of heterozygosity (LOH) analysis was performed in epithelial ovarian cancers (EOC) to further characterize a previously identified candidate tumor suppressor gene (TSG) region encompassing D17S801 at chromosomal region 17q25.1. LOH of at least one informative marker was observed for 100 (71%) of 140 malignant EOC samples in an analysis of 6 polymorphic markers (cen‐D17S1839‐D17S785‐D17S1817‐D17S801‐D17S751‐D17S722‐tel). The combined LOH analysis revealed a 453 kilobase (Kb) minimal region of deletion (MRD) bounded by D17S1817 and D17S751. Human and mouse genome assemblies were used to resolve marker inconsistencies in the D17S1839‐D17S722 interval and identify candidates. The region contains 32 known and strongly predicted genes, 9 of which overlap the MRD. The reference genomic sequences share nearly identical gene structures and the organization of the region is highly collinear. Although, the region does not show any large internal duplications, a 1.5 Kb inverted duplicated sequence of 87% nucleotide identity was observed in a 13 Kb region surrounding D17S801. Transcriptome analysis by Affymetrix GeneChip® and reverse transcription (RT)‐polymerase chain reaction (PCR) methods of 3 well characterized EOC cell lines and primary cultures of normal ovarian surface epithelial (NOSE) cells was performed with 32 candidates spanning D17S1839‐D17S722 interval. RT‐PCR analysis of 8 known or strongly predicted genes residing in the MRD in 10 EOC samples, that exhibited LOH of the MRD, identified FLJ22341 as a strong candidate TSG. The proximal repeat sequence of D17S801 occurs 8 Kb upstream of the putative promoter region of FLJ22341. RT‐PCR analysis of the EOC samples and cell lines identified DKFZP434P0316 that maps proximal to the MRD, as a candidate. While Affymetrix technology was useful for initially eliminating less promising candidates, subsequent RT‐PCR analysis of well‐characterized EOC samples was essential to prioritize TSG candidates for further study. © 2005 Wiley‐Liss, Inc.
Hypermethylation patterns in the Fhit regulatory region are tissue specific
Authors: Guler Gülnur , Iliopoulos Dimitrios , Han Shuang‐Yin , Fong Louise Y.Y. , Lubet Ronald A. , Grubbs Clinton J. , Huebner Kay
Published: June 2005

DNA hypermethylation is associated with decreased expression of tumor suppressor genes. We previously observed decreased Fhit expression and Fhit promoter region hypermethylation in rodent tumors induced by various carcinogens, and noted that the 5′ regulatory regions in the promoter, exon 1, and intron 1 were differentially methylated, depending on the tissue of origin. Because different carcinogens were used for induction of tumors of the different organs, we could not conclude that the methylation patterns were tissue‐specific. To determine if in rat tissues: (1) Fhit methylation status is related to expression levels and (2) Fhit methylation patterns were tissue‐ or carcinogen‐specific, we examined Fhit methylation status and expression levels in DMBA‐ and MNU‐induced benign and malignant mammary tumors. Fhit intron 1 was methylated in 3/9 DMBA and all of MNU‐induced benign mammary tumors, in association with reduced Fhit expression levels; Fhit promoter and intron 1 were methylated in all DMBA and MNU‐induced carcinomas in association with highly reduced Fhit expression levels. Treatment of rat cancer cells in vitro with the DNA methyltransferase inhibitor, 5′‐Aza‐2′deoxycytidine, for 4 d, increased Fhit expression and altered the methylation status. Before treatment, both promoter and intron 1 regions were methylated; after treatment, only intron 1 remained methylated. Thus, in carcinogen‐exposed rat tissues there is an overall association of Fhit expression with regulatory region methylation, and hypermethylation patterns did not vary with carcinogen. The specific patterns of hypermethylated CpGs in the Fhit regulatory regions thus appear to be tissue‐specific. Published 2005 Wiley‐Liss, Inc.
Characterization of medroxyprogesterone and DMBA‐induced multilineage mammary tumors by gene expression profiling
Authors: Yin Yuzhi , Bai Renkui , Russell Robert G. , Beildeck Marcy E. , Xie Zhihui , Kopelovich Levy , Glazer Robert I.
Published: June 2005

Mouse mammary tumors arising during medroxyprogesterone‐DMBA‐mediated mammary carcinogenesis comprised three distinct phenotypes: adenocarcinoma, squamous cell carcinoma, and myoepithelial carcinoma. The molecular signature for each of the three tumor subsets was characterized by gene microarray analysis, and three distinct sets of gene expression profiles were obtained that were corroborated in part by quantitative RT‐PCR and immunohistochemistry. These results suggest that this carcinogenesis and gene expression model will be useful for rapidly assessing the histopathological differences arising in mammary carcinogenesis and the effects of tumor promoting or chemoprevention agents. Published 2005 Wiley‐Liss, Inc.
Hibernation induction trigger reduces hypoxic damage of swine skeletal muscle
Authors: Hong Jinback , Sigg Daniel C. , Coles James A. , Oeltgen Peter R. , Harlow Henry J. , Soule Charles L. , Iaizzo Paul A.
Published: June 2005

A link between the cardioprotective benefits of pharmacological preconditioning and natural mammalian hibernation is considered to involve the cellular activation of opioid receptors and subsequent opening of KATP channels. In previous studies, we have demonstrated the protective effects of specific δ‐opioid agonists against porcine cardiac ischemia/reperfusion injury. We hypothesize here that preincubation with hibernation induction trigger (HIT) should confer a similar protection in skeletal muscles. Therefore, muscle bundles from swine were pretreated with plasma from hibernating woodchucks (HWP) for 30 min, then exposed to hypoxia for 90 min and reoxygenation for 120 min. Stimulated twitch forces were assessed. The functional effects of pretreatment with nonhibernation (summer) woodchuck plasma, a KATP blocker, or opioid antagonist were also studied. During the reoxygenation period, significantly greater force recoveries were observed only for bundles pretreated with HWP; this response was blocked by naloxone (P < 0.05). We conclude that HIT pretreatment could be used to confer protection against hypoxia/reperfusion injury of skeletal muscles of nonhibernators; it could potentially be utilized to prevent injury during surgical procedures requiring ischemia. © 2005 Wiley Periodicals, Inc. Muscle Nerve, 2005
NMR and DFT investigations of the substituent and solvent effect on amino—imino tautomerism in acridin‐9‐amines substituted at the exocyclic nitrogen atom
Authors: Ebead Youssif , Wróblewska Agnieszka , Krzymiński Karol , Rak Janusz , Błażejowski Jerzy
Published: June 2005

The 1H and 13C NMR spectra of 9‐(methoxyamino)acridine (1) and 9‐hydrazinoacridine (2) show that these compounds exist principally in the imino tautomeric form in CDCl3, acetone‐d6, CD3CN, DMSO‐d6 and Py‐d5, all solvents with different polarities and abilities to participate in specific interactions. The spectra of the other two compounds investigated—N‐(2‐chloroethyl)acridin‐9‐amine (3) and N‐(5‐methylpyridin‐2‐yl)acridin‐9‐amine (4)—indicate that they coexist in the amino and imino forms. The amino tautomer of compound 3 predominates in CDCl3, CD3CN and Py‐d5 and that of compound 4 in CDCl3 and Py‐d5. On the other hand, the amino and imino forms of compound 3 coexist in acetone‐d6 and probably DMSO‐d6, whereas those of compound 4 coexist in acetone‐d6 and DMSO‐d6. The positions of the signals in the NMR spectra compare qualitatively with those predicted computationally at the GIAO/DFT level of theory. The equilibrium constants predicted by the DFT(PCM) method are in agreement with the results of NMR spectral analysis. In general, both the data predicted at the DFT level of theory and x‐ray structural data show that the imino tautomers display a ‘butterfly’‐type geometry, whereas the amino forms are characterized by an almost flat acridine moiety. Electron‐attracting substituents at the exocyclic N atom improve the stability of the imino form, and electron‐withdrawing substituents do likewise for the amino form. The importance of tautomeric phenomena in the context of the ability of acridin‐9‐amines to participate in specific interactions is outlined in brief, as are the possible applications of these compounds as probes of environmental properties. Copyright © 2005 John Wiley & Sons, Ltd.
Critical properties of thin films of polymer solutions
Authors: Rizzotto M. , Szleifer I.
Published: June 2005

The critical properties of polymer solutions confined in thin‐film environments is studied with simple scaling arguments and a molecular theory. For purely repulsive surfaces, the critical volume fraction is a universal function of x = N1/2/L, where N is the chain length and L is the film thickness. The critical volume fraction is nonmonotonic in x and shows a deep minimum at a film thickness several times larger than the chain's radius of gyration. This nonmonotonic behavior results from the interplay between the surface–polymer entropic repulsion and the tendency of the film to avoid large density gradients. The critical temperature is a monotonically increasing function of L, as L goes from the two‐dimensional limit to the three‐dimensional limit. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1849–1853, 2005
Synergism of electrochemical and mechanical factors in porous silicon growth
Authors: Parkhutik Vitali , Udagawa Masayuki , Harima Yutaka
Published: June 2005

Here we report new data on mechanical properties of porous silicon films that support a model where both electrochemistry of local dissolution of silicon and mechanical stress factors are playing roles. Using micro‐Raman spectroscopy allowed us to establish the presence of rather high tensile stress in monocrystalline Si in the close vicinity of the interface with porous silicon that supports our assumption of stress‐enhanced pore growth. Our recent data on spontaneous layering of porous silicon films under steady‐state conditions of p‐Si growth also show that the mechanical stress is a key factor in formation of the structure of porous silicon additionally to conventional electrochemical factors. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light propagation in a porous silicon waveguide: an optical modes analysis in near‐field
Authors: Bruyant A. , Stefanon I. , Lerondel G. , Blaize S. , Aubert S. , Bachelot R. , Royer P. , Pirasteh P. , Charrier J. , Joubert P.
Published: June 2005

We report on the first near‐field observation of light propagation in a porous silicon planar waveguide. The observation has been made possible using a scattering‐type scanning near field optical microscope (s‐SNOM). Optical constants of the propating modes are retrieved by two methods first, from the intensity profile and then from the complex field profile, the latter being obtained with a heterodyne interferometric setup. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous silicon substrates for neurons culturing and bio‐photonic sensing
Authors: de‐Leon S. Ben‐Tabou , Oren R. , Spira M. E. , Korbakov N. , Yitzchaik S. , Sa'ar A.
Published: June 2005

In this work we report on culturing of Aplysia neurons and vertebrate cells to porous silicon substrates and on the first steps toward characterizing porous silicon as a biosensor of neural activity. Neurons cultured on porous silicon substrates survived for at least one week showing normal passive membrane properties and generation of action potentials. We have investigated several mechanisms that take advantage of the optical properties of porous silicon for transducing both electrical and chemical neuronal activities into photonic signals. For example, the photoluminescence response to voltage and the reflectivity response to chemical changes were investigated. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sum‐frequency generation from surface species in porous silicon
Authors: Mattei G. , Valentini V. , Yakovlev V. A. , Mani A. A. , Sartenaer Y. , Thiry P. A. , Peremans A. , Caudano Y. , Dreesen L. , Humbert C. , Busson B. , Vidal F. , Tadjeddine A.
Published: June 2005

For the first time, the sum‐frequency generation (SFG) spectra of surface species have been measured in porous silicon (PS) layers. The range of the vibrations 2000–2300 cm–1 for the native species Si–Hx has been explored. Furthermore for the studied mesoporous materials, it has been found that, as opposed to the infrared absorption, the SFG signal increases with porosity. Finally, the angular dependence and the enhancement of the SFG signal were measured in a one‐dimensional PS photonic crystal structure with a defect producing an energy level in the photonic band gap. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of semiconductor nanowires by pulsed current electrodeposition of metal with subsequent sulfurization
Authors: Gavrilov S. , Nosova L. , Sieber I. , Belaidi A. , Dloczik L. , Dittrich Th.
Published: June 2005

Semiconductor nanowires of CdS and CuxS were embedded into porous anodic alumina (PAA) by sulfurization of the metal precursors. Pores of PAA were filled with Cd and Cu by ac electrochemical preparation while the PAA layers remained on the Al‐substrate. Deposited metal and semiconductor wires were characterized by scanning electron microscopy and X‐ray diffraction. Photovoltage spectroscopy was applied to demonstrate semiconductor behaviour of CdS nanowires manufactured by the proposed technique. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence mechanisms of Tb3+‐doped porous GaP
Authors: Elhouichet H. , Oueslati M. , Lorrain N. , Langa S. , Tiginyanu I. M. , Föll H.
Published: June 2005

Porous GaP (por‐GaP) samples are doped with terbium ions (Tb3+) by simple impregnation followed by high‐temperature annealing. From scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX) analysis, we show that the por‐GaP skeleton is conserved and the Tb3+ ions are uniformly distributed in the host. The influence of annealing temperature on the luminescence intensity is explored. The photoluminescence (PL) intensity is found to be constant at temperatures lower than 130 K and quenches weakly for temperatures higher than 130 K. A quantitative model for excitation and de‐excitation processes of Tb3+ in por‐GaP based on the recombination of bound excitons to a Tb‐related trap site is proposed that shows good agreement with experimental results. We show that the PL quenching above 130 K can be interpreted in terms of both a back transfer of Tb3+ excitation to the host and a weak thermalization of bound electrons to the conduction band. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Monte Carlo simulation of electrochemical oscillations in the electropolishing regime
Authors: Foca E. , Carstensen J. , Föll H.
Published: June 2005

Current oscillations, and for the first time, voltage oscillations too, which occur at the Si electrode in a HF electrolyte in the electropolishing regime, are quantitatively calculated using Monte Carlo simulations based on the current burst model. Results obtained for relatively large areas comprise stable, unstable and damped oscillations, the formation of synchronized domains, and the influence of external voltage modulations, always in conjunction with all other parameters like oxide thickness and roughness behavior, or electrode capacitance. The results show good quantitative agreement in all respects with the experiments. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab initio study of birefringent porous silicon
Authors: Bonder Yuri , Wang Chumin
Published: June 2005

Optical properties of birefringent porous‐silicon layers are studied within the density functional theory. Starting from a (110)‐oriented supercell of 32 silicon atoms, elliptic columns of atoms in [100] and [010] directions are removed. The dangling bonds are saturated with hydrogen atoms. The results show an in‐plane anisotropy in the refractive index and in the absorption coefficient, i.e., a birefringence response. The difference Δn defined as $ n_{[1\bar 10]} $–$ n_{[001]} $ is compared with experimental data and a good agreement is observed. Also, the calculated absorption coefficients behave very closely to the measured ones. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Micro‐Raman study of columnar GaAs nanostructures
Authors: Prunici Pavel , Irmer Gert , Monecke Jochen , Sirbu Lilian , Tiginyanu Ion
Published: June 2005

Micro‐Raman scattering spectra of bulk and porous GaAs and of individual nanocolumns were studied. The GaAs nanocolumns have radii of 50–100 nm and lengths between 5 and 25 µm. The experimental data are compared with the results of calculations predicting coupled LO‐phonon–plasmon and coupled Fröhlich‐plasmon modes using a dielectric function derived on the basis of an appropriate two‐dimensional effective medium theory. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Boron passivation and its reactivation in mesoporous silicon: a “chemical” model
Authors: Garrone E. , Geobaldo F. , Rivolo P. , Salvador G. P. , Pallavidino L. , Boarino L. , Amato G. , Giamello E. , Chiesa M. , Gobetto R. , Ugliengo P.
Published: June 2005

A chemical model is proposed to explain the passivation of carriers upon etching and their reactivation by the presence of gases in p+‐type mesoporous silicon (m‐PS). The model is based on the results obtained by means of FTIR, EPR, NMR spectroscopies and ab‐initio calculations. This chemical description accounts for the behaviour of mPS when contacted with NO2 or NH3. B atoms in subsurface location play a prominent role. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spontaneous layering of porous silicon layers formed at high current densities
Authors: Parkhutik Vitali , Curiel‐Esparza Jorge , Millan Mari‐Carmen , Albella Jose
Published: June 2005

We report here a curious effect of spontaneous fracturing of the silicon layers formed in galvanostatic conditions at medium and high current densities. Instead of formation of homogeneous p‐Si layer as at low currents, a stack of thin layers is formed. Each layer is nearly separated from others and possesses rather flat interfaces. The effects is observed using p+‐Si wafers for the p‐Si formation and starts being noticeable at above 100 mA/cm2.

We interpret these results in terms of the porous silicon growth model where generation of dynamic mechanical stress during the p‐Si growth causes sharp changes in Si dissolution mechanism from anisotropic etching of individual needle‐like pores in silicon to their branching and isotropic etching. At this moment p‐Si layer loses its adhesion to the surface of Si wafer and another p‐Si layer starts growing. One of the mechanisms triggering on the separation of p‐Si layers from one another is a fluctuation of local anodic current in the pore bottoms associated with gas bubble evolution during the p‐Si formation. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of NO2 molecule adsorption on free charge carriers and spin centers in porous silicon
Authors: Konstantinova E. A. , Osminkina L. A. , Sharov C. S. , Timoshenko V. Yu. , Kashkarov P. K.
Published: June 2005

The effect of nitrogen dioxide (NO2) adsorption on free charge carriers and spin centers in porous silicon has been studied by FTIR and ESR spectroscopy. The silicon dangling bond (Pb1‐center) density rises with increasing NO2 pressure (P) while free charge carrier concentration depends on P nonmonotonically. The experimental results are explained by a microscopic model taking into account both the formation of P–(NO2)– donor–acceptor pairs and NO2‐induced oxidation of Si nanocrystal surfaces. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Raman measurements on nanocolumnar ZnO crystals
Authors: Marí B. , Cembrero J. , Manjón F. J. , Mollar M. , Gómez R.
Published: June 2005

Hexagonal zinc oxide nanocolumns have been grown on conducting F‐doped SnO2 substrates by galvanostatic electrodeposition. Raman and photoluminescence spectra of the ZnO nanocolumns have been measured in several samples with different size distributions as a function of the annealing temperature. Photoluminescence properties of ZnO nanocolumns are strongly influenced by the crystalline quality of the samples. The dependence of the crystalline quality of the samples on the growth parameters and annealing temperature is discussed. In particular, the Raman spectra of as‐grown samples exhibit broad bands that correlate perfectly with the one‐phonon density of states obtained from recent ab initio calculations. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)