bluuebunny/crossref_metadata_2025 huggingface dataset:
Mediated and direct effects of the North Atlantic Ocean on winter temperatures in northwest Europe
Authors: Junge Martina M. , Stephenson David B.
Published: February 2003

This study has used a multiple regression model to quantify the importance of wintertime mean North Atlantic sea‐surface temperatures (SSTs) for explaining (simultaneous) variations in wintertime mean temperatures in northwestern Europe. Although wintertime temperature variations are primarily determined by atmospheric flow patterns, it has been speculated that North Atlantic SSTs might also provide some additional information. To test this hypothesis, we have attempted to explain 1900–93 variations in wintertime mean central England temperature (CET) by using multiple regression with contemporaneous winter mean North Atlantic sea‐level pressures (SLPs) and SSTs as explanatory variables. With no SST information, the leading SLP patterns (including the North Atlantic oscillation) explain 63% of the total variance in winter mean CET; however, SSTs alone are capable of explaining only 16% of the variance in winter mean CET. Much of the SST effect is ‘indirect’ in that it supplies no more significant information than already contained in the mean SLP; e.g. both SLP and SST together can only explain 68% of the variance. However, there is a small (5% variance) direct effect due to SST that is not mediated by mean SLP, which has a spatial pattern resembling the Newfoundland SST pattern identified by Ratcliffe and Murray (1970. Quarterly Journal of the Royal Meteorological Society 96: 226–246). In predictive mode, however, using explanatory variables from preceding seasons, SSTs contain more information than SLP factors. On longer time scales, the variance explained by contemporaneous SST increases, but the SLP explanatory variables still provide a better model than the SST variables. Copyright © 2003 Royal Meteorological Society
Microclimate of a desert playa: evaluation of annual radiation, energy, and water budgets components
Authors: Malek Esmaiel
Published: February 2003

We set up two automatic weather stations over a playa (the flat floor of an undrained desert basin that, at times, becomes a shallow lake), approximately 65 km east–west by 130 km north–south, located in Dugway (40° 08′N, 113° 27′W, 1124 m above mean sea level) in northwestern Utah, USA, in 1999. These stations measured the radiation budget components, namely: incoming Rsi and outgoing Rso solar or shortwave radiation, using two Kipp and Zonen pyranometers (one inverted), the incoming Rli (or atmospheric) and outgoing Rlo (or terrestrial) longwave radiation, using two Kipp and Zonen pyrgeometers (one inverted) during the year 2000. These sensors were ventilated throughout the year to prevent dew and frost formation. Summation of these components yields the net radiation Rn. We also measured the air temperatures and humidity at 1 and 2 m and the soil moisture and temperature (Campbell Sci., Inc., CSI) to evaluate the energy budget components (latent (LE), sensible (H), and the soil (Gsur) heat fluxes). The 10 m wind speed U10 and direction (R.M. Young wind monitor), precipitation (CSI), and the surface temperature (Radiation and Energy Balance Systems, REBS) were also measured during 2000. The measurements were taken every 2 s, averaged into 20 min, continuously, throughout the year 2000. The annual comparison of radiation budget components indicates that about 34% of the annual Rsi (6937.7 MJ m−2 year−1) was reflected back to the sky as Rso, with Rli and Rlo amounting to 9943.4 MJ m−2 year−1 and 12 789.7 MJ m−2 year−1 respectively. This yields about 1634.3 MJ m−2 year−1 as Rn, which is about 24% of the annual Rsi. Of the total 1634.3 MJ m−2 year−1 available energy, about 25% was used for the process of evaporation (LE) and 77% for heating the air (H). The annual heat contribution from the soil to the energy budget amounted to 2% during the experimental period. Our studies showed that the total annual measured precipitation amounted to 108.0 mm year−1 during the year 2000, but the total evaporation was 167.6 mm year−1, which means some water was extracted from the shallow water table (about 60 cm on the average depth during the year 2000). Copyright © 2003 Royal Meteorological Society.
Changes in spring weather conditions and atmospheric circulation in Estonia (1955–95)
Authors: Keevallik Sirje
Published: February 2003

An analysis has been undertaken at Tiirikoja Meteorological Station to investigate changes in the main weather elements in late winter and spring during the period 1955–95. The relationship between these changes and the trends in the atmospheric circulation above Estonia have also been analysed. The latter was estimated from wind speed and direction data recorded at Tallinn Aerological Station at two isobaric levels (500 and 850 hPa). These data permitted the analysts to calculate zonal and meridional components of wind velocity at both levels. Linear trends were fitted to time series of monthly averages of all parameters under consideration. The results indicate that significant changes in meteorological parameters took place in March. These changes are statistically related to the changes in the average airflow in the free atmosphere above Estonia. In March the wind speed at the 500 and 850 hPa isobaric levels increased and the average airflow turned from WNW or NW to SW or WSW. Such changes in the atmospheric circulation can only partly be attributed to the intensification of the North Atlantic oscillation. Copyright © 2003 Royal Meteorological Society
A conceptual model relating the quasi‐biennial oscillation and the tropospheric biennial oscillation
Authors: Kwan Kok Foo , Samah Azizan Abu
Published: February 2003

A survey of the zonal wind throughout the troposphere and the lower stratosphere near the equator is made for the 41 year period of 1958–98. A similar survey of the 500 hPa geopotential height, sea‐surface temperature (SST) and tropopause height is also made, except that the survey period for the tropopause height is shorter than 41 years due to unavailability of data.

Other than the well‐known quasi‐biennial oscillation (QBO) feature in the lower stratosphere and the tropospheric biennial oscillation (TBO) feature exhibited by the SST, similar oscillation features are found throughout the whole troposphere by both surveys. Pearson cross‐correlation functions and smoothed power spectrums of all meteorological parameters used in the surveys indicate that all these features are statistically significant at the 90–95% confidence level.

The Pearson cross‐correlation functions are further used to deduce a conceptual model relating the QBO in the lower stratosphere and the TBO feature found in the interannual variability of monsoon pattern at and near the surface of the Earth. The QBO and TBO seem to be interrelated to each other thermodynamically. Thoughts on QBO–TBO connections in this conceptual model are tentative and await full testing. Copyright © 2003 Royal Meteorological Society.
The contribution of increased incoming shortwave radiation to the retreat of the Rwenzori Glaciers, East Africa, during the 20th century
Authors: Mölg Thomas , Georges Christian , Kaser Georg
Published: February 2003

Based on (i) the observation of spatially differential glacier retreats in the tropical Rwenzori Range (East Africa) during the 20th century, which are most striking on the mountains Baker and Speke, and (ii) the information on an abrupt climate change to drier conditions in East Africa at the end of the 19th century, the following hypothesis is derived: owing to a drier atmosphere than in a previous period, both accumulation (possibly supported by increasing air temperatures) and convective cloud activity have decreased. Consequently, increased incoming shortwave radiation, especially during the morning hours, induced a differentially increased ablation that could not be compensated by mass advection on the mountains Baker and Speke.

The results obtained from a combined radiation–terrain model, run for one more humid and one drier climatic scenario, confirm the hypothesis by quantifying the correlation between increased incoming shortwave radiation and glacier surface area loss. In the context of modern climate fluctuations, the results are a further indicator for a drastic climatic dislocation in East Africa at the end of the 19th century, leaving a humid regime behind and leading to a relatively dry regime, which is forcing the recession of glaciers not only by less accumulation but also by less protection against shortwave radiation through clouds. Copyright © 2003 Royal Meteorological Society.
Long‐term trends in near‐surface flow over the Baltic
Authors: Pryor S. C. , Barthelmie R. J.
Published: February 2003

We report an analysis of trends in 850 hPa wind speed, as manifest in the NCEP–NCAR reanalysis fields, over the Baltic region during the latter half of the 20th century. The results indicate that annual mean wind speeds over the Baltic significantly increased over the period 1953–99 with the majority of the increase being associated with increases in the upper quartile of the wind speed distribution. Accordingly, much of the change is focused on the winter season. The trends in annual and seasonal mean wind speeds are greatest in relative and absolute sense in the southwest of the Baltic basin, where they are in excess of 0.25 m s−1 per decade for the annual mean. The extremes of the wind‐speed distribution also increased by up to 5 m s−1 over the study period for the wind speed with a 50 year return period, again with the largest magnitude changes in the southwestern Baltic. These changes in wind speed are strongly linked to changes in the synoptic‐scale circulation. The majority of the increase in wintertime wind speeds is attributable to an increase in westerly anticyclonic, westerly cyclonic and northwesterly cyclonic circulation types as manifest in the Grosswetterlagen catalogue, which are in turn related to the recent prevalence of the positive phase of the North Atlantic oscillation. Copyright © 2003 Royal Meteorological Society
Trends affecting pluviometric indices at the Fabra Observatory (Barcelona, NE Spain) from 1917 to 1999
Authors: Lana X. , Serra C. , Burgueño A.
Published: February 2003

A set of daily rainfall amounts collected at the Fabra Observatory (Barcelona, NE Spain) from 1917 to 1999 has made it possible to compute several pluviometric indices at seasonal and annual scales for every year, after applying a low‐pass filter. The first index is obtained by considering the time series of seasonal and annual rainfall amounts. The next two indices evaluate the number of days equalling or exceeding a threshold rainfall level and the average intensity for these days. These procedures are applied to different threshold rainfall levels accounting for all rainy days and the sets of days reaching the 25, 50 and 75% percentile of daily rainfall amounts. The fourth index is defined as the quotient between cumulative rainfall for some class intervals and the total rainfall. Daily amounts falling within the <25, 25–50, 50–75, 75–90 and ≥90% percentile rainfall amounts define the class intervals. Additionally, the same indices are also calculated for the 95% percentile of rainy days, which correspond to outstanding daily amounts. A detailed analysis of the trends affecting all these indices and their statistical significance suggests the effects of a possible climatic change on the pluviometric regime of the Fabra Observatory over the course of the 20th century. Moreover, the resulting trends are compared with those inferred from data from around the planet during the 20th century and with other Mediterranean rain gauges. By comparing this with regional rain data series, the possibility of the heat island effect of the city of Barcelona is argued to be the cause of the significant positive trends found in rainfall amounts. As far as possible linkages between trends on the pluviometric regime and circulation patterns are concerned, a set of cross‐correlations between these indices and the North Atlantic oscillation index has been examined. However, the results are not conclusive, as most of the cross‐correlation coefficients obtained are small and not statistically significant. Copyright © 2003 Royal Meteorological Society
Relationships between rainfall and West African wave disturbances in station observations
Authors: Taleb El Houssein , Druyan Leonard M.
Published: February 2003

Morlet wavelets of the meridional component of daily radiosonde wind observations above four West Africa stations were constructed for May–September seasons, 1950–84, at three vertical levels. The passage of African wave disturbances (AWDs) at each station was detected as statistically significant wavelet amplitudes within two spectral bands. The detected AWD activity, or lack of it, was compared with the precipitation record at each station. Results demonstrate that AWDs account for only a proportion of the seasonal rainfall, implying that other precipitation triggers are also important. In addition, the analysis finds that many AWD traversals fail to initiate heavy rainfall at the selected stations. At Niamey, the average precipitation amount per wave had a positive trend between 1953 and 1978. With few exceptions, seasonal precipitation totals were not correlated with the number of days on which AWDs were detected. Although the seasonal average precipitation amount per AWD day exhibited a positive trend at Niamey between 1953 and 1978, there was no corresponding interannual trend in total seasonal precipitation. Copyright © 2003 Royal Meteorological Society
Comparative dry matter intake and nutrient utilisation efficiency in lactating cattle and buffaloes
Authors: Paul Shyam S , Mandal Asit B , Kannan Alagarsamy , Mandal Guru P , Pathak Nitya N
Published: February 2003

An attempt was made to assess the comparative dry matter intake and nutrient utilisation efficiency of lactating buffaloes and cows based on results obtained from experimental feeding trials conducted in India. Data on dry matter (DM) intake, total digestible nutrient (TDN) intake, digestible crude protein (DCP) intake, body weight or metabolic body size (MBS), body weight change, milk yield or 4% fat‐corrected milk (FCM) yield, milk fat percentage and roughage/concentrate ratio in the diet of lactating buffaloes and cows were collected from published reports. The data were processed and analysed to assess the comparative dry matter intake and nutrient utilisation efficiency using suitable statistical analysis models. DM intake was significantly (P < 0.01) lower in buffaloes (2.57 kg DM per 100 kg body weight or 119.2 g kg−1 MBS) than in cattle (3.09 kg DM per 100 kg body weight or 132.0 g kg−1 MBS). Mean gross energetic efficiency (30.53 versus 27.83%; P < 0.01), gross protein efficiency (45.48 versus 37.06%; P < 0.01), net energetic efficiency (69.16 versus 64.10%; P < 0.05) and net protein efficiency (80.15 versus 59.59%; P < 0.001) were significantly higher in buffaloes than in cattle. Lactating buffaloes consumed significantly less (P < 0.001) protein (75.69 g DCP) and less (P < 0.01) energy (695.9 g TDN) than cows (93.89 g DCP, 774.8 g TDN) for production of 1 kg of 4% fat‐corrected milk. Buffaloes had higher energy and protein utilisation efficiencies as compared with cattle at similar fat‐corrected milk production level, plane of energy and protein nutrition, body size and body weight change. Buffaloes (1.189 kg DM kg−1 4% FCM) consumed a similar (P > 0.05) amount of feed dry matter to that of cows (1.267 kg DM kg−1 4% FCM). However, when DM intake kg−1 FCM (4%) was compared at constant levels of metabolic body size, fat‐corrected milk, body weight change, dietary energy concentration and green forage percentage in the diet, lactating buffaloes consumed significantly less DM kg−1 FCM yield as compared with cattle. It was concluded that DM intake was lower in lactating buffaloes. Moreover, lactating buffaloes utilised dietary dry matter, energy and protein for milk production more efficiently than cattle.

© 2003 Society of Chemical Industry
Magnetic resonance imaging as a predictive tool for sensory characteristics and intramuscular fat content of dry‐cured loin
Authors: Antequera Teresa , Muriel Elena , Rodríguez Pablo G , Cernadas Eva , Ruiz Jorge
Published: February 2003

A novel methodology to non‐invasively and objectively predict sensory traits and intramuscular fat content of dry‐cured Iberian loins was studied. Texture analysis of magnetic resonance images was performed on 47 dry‐cured Iberian loins. Appearance and texture traits were assessed by a 18‐member trained panel, and intramuscular fat content was chemically extracted and quantified for the same samples. Three classes of dry‐cured loin according to each sensory and chemical trait were established (low, medium and high). Using the texture features selected by the floating search method (FSM), a system accuracy of 83% for intramuscular fat content and not lower than 70% for all sensory traits was obtained. These results are encouraging for the application of this methodology, allowing in situ, automatic, objective and non‐destructive classification of loins.

© 2003 Society of Chemical Industry
Cassava root yields and culinary qualities as affected by harvest age and test environment
Authors: Ngeve Jacob M
Published: February 2003

Five cassava genotypes were grown at five contrasting sites in Cameroon, and their roots were harvested 6, 8, 10, 12, 14 and 16 months after planting, to determine the effects of growing environment and harvest age on storage root yields and culinary qualities. The highest root yields were obtained at Ekona (26.3 t ha−1), whereas the highest root counts were recorded at Bertoua (33 roots per 10 m2). Root yields were lowest (2.9 t ha−1) when roots were harvested at 6 months, but continued to bulk up to 18.5 t ha−1 at 16 months. The greatest root increase (9.3 t ha−1) was observed between 8 and 12 months. Improved and local varieties had comparable dry matter contents (39%). All clones cooked when harvested at 6 and 8 months; thereafter, improved clones did not cook, and cooking duration continued to increase even for the local variety, accounting for the difficulty seen in disseminating these newly developed clones to growers. Cooking durations of roots were longer at Nkolbisson, Bertoua and Ebolowa than at Ekona and Yoke. Soil carbon content was negatively correlated (r = −0.999***) with mealiness but not with cooking duration. Cooking quality appears to be under genetic and environmental control. Further studies to elucidate the role of the environment on cookability should concentrate on duration of the rainy and dry seasons, soil physical and chemical properties, and starch chemistry of the genotypes. Suggestions for further research are discussed.

© 2003 Society of Chemical Industry
Flavour index and aroma profiles of fresh and processed honeys
Authors: Serra Bonvehí Josep , Ventura Coll Francesc
Published: February 2003

This paper discusses the importance of flavour profiling in detecting indicative parameters for quality control of fresh and heated honey. Flavour compounds of six unifloral honeys (Lavandula stoechas, Castanea sativa, Dorycnium pentaphyllum, Rosmarinus officinalis, Eucalyptus sp and Robinia pseudoacacia) were investigated. The aroma extracts were obtained by a two‐step procedure involving (i) preliminary steam distillation under reduced pressure to evaluate the methylpyrazines generated in heated honeys by spectrophotometry (flavour index) and (ii) Likens–Nickerson's simultaneous steam distillation and solvent extraction (SDE) method with added NaCl. A combined total of 64 compounds were detected by gas chromatography/mass spectrometry (GC/MS), 58 of which were identified. Some compounds appeared to be characteristic of the floral source, particularly in Spanish lavender (methylated aliphatic acids and aromatic esters), eucalyptus (2,3‐pentanedione, acetoin, 1‐hexyl alcohol, 2‐acetyl‐5‐methylfuran, furfuryl propionate, 2‐phenylacetaldehyde and nerolidol), chestnut (acetophenone and 2‐aminoacetophenone), rosemary and D pentaphyllum (aromatic acids and esters, 2‐phenylacetaldehyde, farnesol and thymol) honeys. Robinia honey samples were characterised by very low levels of aromatic compounds. Twenty‐six flavour compounds were statistically closely related to the floral origin of the honeys (P ≤ 0.05). The flavour index was evaluated progressively in heated honeys, whereas in fresh honeys it showed a minimal value.

© 2003 Society of Chemical Industry
Assessment of nutritional compounds and antinutritional factors in pea (Pisum sativum) seeds
Authors: Vidal‐Valverde Concepción , Frias Juana , Hernández Amelia , Martín‐Alvarez Pedro J , Sierra Isabel , Rodríguez Carmen , Blazquez Inmaculada , Vicente Gema
Published: February 2003

The nutrient and antinutritional factor content of 18 pea lines was studied. The following levels were found: non‐protein nitrogen 5.2–10.2 g kg−1 DM, protein nitrogen 35.3–42.4 g kg−1 DM, lysine 50.7–76.3 g kg−1 protein DM, histidine 17.8–24.8 g kg−1 protein DM, tyrosine 22.6–30.0 g kg−1 protein DM, protein 25.9–31.9% DM, in vitro protein digestibility 89.3–95.6%, vitamin B1 5.9–10.3 mg kg−1 DM, vitamin B2 1.1–3.7 mg kg−1 DM, sucrose 11.6–25.4 g kg−1 DM, raffinose 4.1–10.3 g kg−1 DM, stachyose 10.7–26.7 g kg−1 DM, verbascose 0.0–26.7 g kg−1 DM, total α‐galactosides 22.6–63.4 g kg−1 DM, trypsin inhibitor activity 0.8–8.4 TIU mg−1 DM, inositol hexaphosphate 2.3–6.5 g kg−1 DM, inositol pentaphosphate 0.1–1.8 g kg−1 DM and total inositol phosphates 2.8–7.1 g kg−1 DM. Peas with yellow cotyledons had the highest trypsin inhibitor activities, those with light green cotyledons had the highest lysine contents, and those with dark green cotyledons were the richest in vitamins B1 and B2. Peas with brown testae had the lowest verbascose and sucrose contents, while they were the richest in inositol hexaphosphate. Smaller peas were characterised by the highest protein nitrogen contents as well as the highest contents of vitamins B1 and B2, verbascose and inositol pentaphosphate. Peas of medium size showed the lowest verbascose, α‐galactoside and vitamin B2 contents. Bigger peas showed the lowest inositol pentaphosphate contents.

© 2003 Society of Chemical Industry
Emission patterns of wound volatile compounds following injury of ripe strawberry fruit
Authors: Hamilton‐Kemp Thomas R , Archbold Douglas D , Collins Randall W , Yu Keshun
Published: February 2003

Volatile compounds emitted from plants following wounding influence the growth of fungal pathogens, including Botrytis cinerea (grey mould), which causes serious economic loss of strawberry fruit. In the present study the patterns of volatile compound emission from ripe strawberry fruit, comprising store‐purchased fruit and two known cultivars, were determined following injury, using solid phase microextraction analysis to sample a stream of air continuously flowing over the fruit. The principal compounds produced from all fruits comprised C6 aldehydes, alcohols and acetate and butyrate esters derived from the lipoxygenase–hydroperoxide lyase pathway. There was an initial burst of production of aldehydes, including t‐2‐hexenal, following wounding and then a gradual decline, which in one cultivar continued for 3 h. t‐2‐Hexenal is of special interest, since it has been shown to inhibit or promote Botrytis growth in vitro depending on concentration. The acetate esters t‐2‐hexenyl acetate, c‐3‐hexenyl acetate and hexyl acetate were major wound compounds released by the fruit and were produced for 3 h after wounding. The production of relatively large quantities of wound‐derived esters is markedly different from the patterns observed for most vegetative tissue. Knowledge of the wound compounds produced by strawberry fruit and their profiles of emission after injury provides a basis for studies of the potential roles of these compounds in pathogen development on fruit.

© 2003 Society of Chemical Industry
Comparison of aroma characteristics of 16 fish species by sensory evaluation and gas chromatographic analysis
Authors: Morita Kae , Kubota Kikue , Aishima Tetsuo
Published: February 2003

The aroma properties of fish broths prepared from 16 fish species (10 saltwater, three freshwater, two anadromous and one brackish water species) were described quantitatively by reference to 10 sensory attributes. Principal component analysis (PCA) and cluster analysis of sensory attributes classified the fish into four groups. Group 1, characterised by a strong ‘green’ odour, comprised all three freshwater species (loach, pond smelt and carp), two saltwater whitefish species (snapper and conger) and eel. Group 2 included migratory coastal species (sardine, banded blue‐sprat and mackerel) and was distinguished by strong ‘fish oil’ and ‘grilled fish’ notes. Group 3 consisted of swordfish, sablefish and salmon, which exhibited a strong ‘fried chicken’ note. Group 4 included flounder, cod, tuna and goby, which were scored high for ‘cooked fish’, ‘roasted soy sauce’, ‘canned tuna’ and ‘sweet’ aromas. Partial least squares regression (PLSR) models derived from selected influential peaks in the gas chromatograms of the volatile components in the broths for each attribute were highly predictive (R2 ≥ 0.936). The selected peaks corresponded well to each sensory attribute.

© 2003 Society of Chemical Industry
Effect of harvest time and storage conditions on almond kernel oil and sugar composition
Authors: Kazantzis Ioannis , Nanos George D , Stavroulakis George G
Published: February 2003

The effect of storage for 6 months at 5 °C (80% RH) versus 20 °C (60% RH) of shelled versus in‐shell almonds was studied on early versus late harvested nuts from ‘Ferragnes’ and ‘Texas’ trees. Kernel quality characteristics, oil composition and sugar composition were determined initially and after 6 months of storage. Early harvested almonds had similar kernel weight to but higher moisture content than late harvested almonds after 6 months of storage. Early harvested almonds also had similar oil quality (based on ultraviolet absorption coefficient measurements) and oil composition but lower sugar content and modified sugar composition compared with late harvested almonds. Storage of shelled almonds resulted in kernels with higher oil content, better oil quality, similar oil composition, similar sugar content and some modifications in sugar composition compared with in‐shell stored almonds. Finally, storage for 6 months at either 5 or 20 °C resulted in lower moisture content, higher oil content, similar oil quality and composition, similar sugar content and some modifications in sugar composition compared with freshly harvested almonds. Almonds stored at 5 °C retained higher kernel weight and moisture content than almonds stored at 20 °C.

© 2003 Society of Chemical Industry
The effect of process time and temperature on the accumulation of polar compounds in cottonseed oil during deep‐fat frying
Authors: Houhoula Dimitra P , Oreopoulou Vassiliki , Tzia Constantina
Published: February 2003

The deterioration of oil during successive fryings of potato chips, especially the accumulation of polar compounds, was studied in the temperature range 155–195 °C. The content of polar compounds increased linearly with process time. The analysis of individual polar compounds showed that the products of thermal and oxidative degradation dominated over the products of hydrolytic cleavage as frying proceeded. Dimeric triglycerides increased linearly with process time, while polymerised triglycerides increased exponentially. The rate constants of the degradation reactions increased slightly with temperature, following an Arrhenius‐type equation. Oxidised triglycerides increased with frying time up to 6 h, thereafter remaining constant or increasing further upon prolonged frying. The increase was greater at higher temperature. The products of hydrolytic cleavage were not significantly affected by temperature. Mono‐ and diglycerides increased initially to reach a plateau, while free fatty acids remained almost constant throughout frying. The thermo‐oxidative alterations induced by heating the oil were also measured and compared with those observed during frying at the same temperature. Dimeric and polymerised triglycerides showed higher rates of increase during heating as compared with frying at the same temperature.

© 2003 Society of Chemical Industry
Analysis of the temperature effect on the components of plant digestibility in two populations of perennial ryegrass
Authors: Groot Jeroen C J , Lantinga Egbert A , Neuteboom Jan H , Deinum Bauke
Published: February 2003

For the development of mechanistic models of herbage digestibility, quantitative insight into the effects of age, temperature and cultivar on digestibility characteristics of individual plant parts is needed. Towards that goal, glasshouse experiments were conducted at day/night temperatures of 13/8, 18/13 and 23/18 °C with vegetative and reproductive crops of two populations of perennial ryegrass (Lolium perenne L) selected for differences in leaf blade digestibility. Cell wall content (CWC) and true cell wall and organic matter digestibility (CWD and OMD) of vegetative and reproductive tillers were related to dimensions, mass, CWC and digestibility of separate plant parts. Compared with the vegetative tillers, the reproductive tillers had higher rates of leaf appearance, organic matter growth and CWD decline. Strikingly, for both tiller types, no direct effect of temperature on whole tiller CWD was observed, since temperature effects could be eliminated completely by relating CWD to development stage (DVS) expressed as number of leaves appearing on the main tiller. Temperature effects on CWD were restricted to its influence on tiller development rate only. The decline of CWD of individual plant parts with DVS in the reproductive tillers could be described with a negative exponential curve, which reached an asymptote that was higher for leaf blades (755 g kg−1) than for leaf sheaths (491 g kg−1) and stem internodes (230 g kg−1). However, all plant parts in both tiller types had the same fractional CWD decline rate of 0.395 per leaf appearance interval, independent of plant part insertion level, population or temperature. Differences between temperature treatments in OMD were caused by the higher CWC of plant parts at higher temperature, due to a stronger decline of the specific organic matter mass than of the specific cell wall mass of plant parts at increasing temperature. Differences in whole tiller OMD between populations were observed only for vegetative tillers and were also caused by differences in CWC. It is concluded that temperature increase accelerated both the tiller development rate and the rate of decline of CWD during aging to the same extent, whereas plant parts responded similarly in the fractional CWD decline pattern as a function of DVS. These trends offer unique possibilities for modelling grass digestibility under contrasting temperature regimes.

© 2003 Society of Chemical Industry
Plant sterols in vegetables, fruits and berries
Authors: Piironen Vieno , Toivo Jari , Puupponen‐Pimiä Riitta , Lampi Anna‐Maija
Published: February 2003

The plant sterol contents of the most important vegetables, fruits and berries available in Finland were determined by capillary gas chromatography. The sample preparation procedure included both acid and alkaline hydrolysis to liberate sterols from their conjugates. The plant sterol contents of fresh vegetables ranged from 51 to 370 mg kg−1 fresh weight (fw) in samples obtained from retail sale. The highest contents (>300 mg kg−1) were measured in broccoli, Brussels sprouts, cauliflower and dill and the lowest (51 mg kg−1) in potato. The range of sterol contents on a dry weight (dw) basis was high, 246–4100 mg kg−1 dw. Considerable variation was also observed when individual samples of some vegetables were compared. Sitosterol was the main sterol (proportion 43–86%) in all vegetables except cucumber and spinach, in which Δ7‐sterols dominated. The total sterol contents were in the range 116–228 mg kg−1 fw in all fresh fruits except avocado, which contained more sterols, 752 mg kg−1 fw. In fresh berries the corresponding range was 60–279 m kg−1 fw. The wild berries lingonberry and blueberry were better plant sterol sources than the cultivated berries blackcurrant, redcurrant and strawberry. In fruits and berries the proportion of sitosterol ranged from 61–93% total sterols. On the basis of the results, the contribution of vegetables, fruits and berries to the total average daily plant sterol intake was estimated to be ca 60 mg.

© 2003 Society of Chemical Industry
Edible oils: discrimination by 1H nuclear magnetic resonance
Authors: Guillén María D , Ruiz Ainhoa
Published: February 2003

The 1H nuclear magnetic resonance (NMR) spectra of 36 edible oil samples of 15 different botanical origins were recorded with a 300 MHz instrument using deuterated chloroform as solvent. The assignment of each of their peaks was made by comparison with those of standard compounds, tristearin, triolein, trilinolein and trilinolenin. For the first time, certain spectral regions of interest, conveniently expanded, together with the chemical shifts of their peaks, are given for 15 oil samples of different botanical origin. The usefulness of each of these spectral regions in the differentiation of oils is discussed. It is shown that 1H NMR spectra can be considered as the fingerprint of each oil sample. It is proved that they provide a great deal of information which permits discrimination between oils of different composition. This discrimination can be made in many cases with the naked eye by observation of certain spectral signals, without any other additional determinations.

© 2003 Society of Chemical Industry
Ergovaline occurrence in grasses infected by fungal endophytes of semi‐arid pastures in Spain
Authors: Vazquez de Aldana Beatriz R , Zabalgogeazcoa Iñigo , Garcia Ciudad Antonia , Garcia Criado Balbino
Published: February 2003

Ergovaline is a mycotoxin produced by fungal endophytes belonging to Neotyphodium and Epichloë spp in several host grass species. Owing to the production of this alkaloid, the ingestion of endophyte‐infected grasses causes toxicosis in grazing animals. The aim of this work was to determine if ergovaline is produced in several grasses (Agrostis castellana Boiss and Reuter, Brachypodium phoenicoides (L) Roemer and Schultes, Dactylis glomerata L, Festuca arundinacea Schreb, Festuca arundinacea Schreb subsp fenas (Lag) Arcangeli, Festuca ovina L, Festuca rubra L, Holcus lanatus L and Lolium perenne L) infected by fungal endophytes in ‘dehesa’ pastures in Spain. Forage and seed samples of several ecotypes of these grass species were analysed for their ergovaline content by HPLC with fluorescence detection. The ergovaline content ranged between 0.03 and 0.85 µg g−1 in forage and 0.28 and 3.17 µg g−1 in seed samples of F arundinacea, between 0.00 and 0.08 µg g−1 in forage and 0.02 and 0.19 µg g−1 in seed samples of F rubra, between 0.00 and 0.02 µg g−1 in forage samples of H lanatus, and was 0.11 µg g−1 in one ecotype of F ovina. All nine ecotypes of F rubra had ergovaline in seed samples, but in three ecotypes the alkaloid was not detected in forage samples. No ergovaline was detected in the other four endophyte‐infected grasses analysed. The ergovaline content should be considered as an anti‐quality parameter to be measured when the nutritional quality of these pastures is evaluated.

© 2003 Society of Chemical Industry
Total and individual glucosinolate contents in inflorescences of eight broccoli cultivars grown under various climatic and fertilisation conditions
Authors: Vallejo F , Tomás‐Barberán F A , Benavente‐García A Gonzalez , García‐Viguera C
Published: February 2003

Total aliphatic, indolic and aromatic glucosinolates were evaluated in the edible portions of fresh harvested inflorescences of five commercial and three experimental broccoli (Brassica oleracea L var italica) cultivars grown under various climatic and agronomic conditions, ie early (winter) or late (spring) season with poor (15 kg ha−1) or rich (150 kg ha−1) sulphur fertilisation, in an attempt to identify differences due to genetic and agronomic factors. The predominant glucosinolates in all broccoli cultivars were 4‐methylsulphinylbutyl‐glucosinolate (glucoraphanin), 3‐indolylmethyl‐glucosinolate (glucobrassicin) and 1‐methoxy‐3‐indolylmethyl‐glucosinolate (neoglucobrassicin). The results showed no significance differences in total glucosinolates between rich and poor fertilisation, whereas total glucosinolates were detected more significantly in the late than in the early season. All broccoli cultivars showed a higher content of indolic glucosinolates than aliphatic glucosinolates. Clear advantages were detected in the analysed commercial cultivars, as the experimental cultivars yielded lower concentrations of these compounds.

© 2003 Society of Chemical Industry
In Vitro Degradation of Trimethylene Carbonate Based (Co)polymers
Authors: Pêgo Ana Paula , Poot André A. , Grijpma Dirk W. , Feijen Jan
Published: February 2003

Trimethylene carbonate (TMC) was copolymerized with D,L‐lactide (DLLA) or with ε‐caprolactone (CL), and the degradation of melt‐pressed solid copolymer films in phosphate‐buffered saline at pH 7.4 and 37 °C was followed for a period of over two years. The parent homopolymers were used as reference materials. The degradation profile of TMC‐DLLA‐ and TMC‐CL based copolymers was similar and was best described by autocatalyzed bulk hydrolysis, preferentially of ester bonds. The hydrolysis rates varied by two orders of magnitude, depending on polymer composition and physical characteristics under the degradation conditions. TMC‐DLLA copolymers degraded faster than the parent homopolymers. The copolymers lost their tensile strength in less than five months, after which mass loss occurred. Copolymers with 50 or 80 mol‐% of TMC underwent total degradation in eleven months. For TMC‐CL copolymers, a slow and gradual decrease in molecular weight and deterioration of the mechanical performance was observed. These copolymers maintained suitable mechanical properties for seventeen months or longer. Chain scission in the semicrystalline copolymers resulted in an increase in crystallinity. In comparison with the CL homopolymer, the introduction of a small amount of TMC (10 mol‐%) significantly reduced the increase in crystallinity during degradation. Poly(TMC) specimens were dimensionally stable and showed a negligible decrease in molecular weight. A 60% decrease in the initial tensile strength of the polymer samples was observed after two years.

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Poly(L‐lactide)‐Degrading Activity in Various Actinomycetes
Authors: Jarerat Amnat , Pranamuda Hardaning , Tokiwa Yutaka
Published: February 2003

The poly(L‐lactide) (PLA)‐degrading ability of actinomycetes obtained from culture collections was examined by the formation of clear zones on PLA‐emulsified agar plates. Using 41 genera (105 strains) of actinomycetes with phylogenetic affiliations based on 16S rRNA sequences, PLA degraders were found to be limited to members of the family Pseudonocardiaceae and related genera. They included Amycolatopsis, Saccharothrix, Lentzea, Kibdelosporangium, and Streptoalloteichus. A large number of PLA degraders were widely distributed within the genus Saccharothrix. Most strains forming clear zones on PLA‐emulsified agar plates also formed clear zones on silk fibroin agar plates. Saccharothrix species showed an ability to degrade PLA films and assimilate degradation products in liquid cultures. No significant change of the molecular weight and polydispersity (Mw/Mn) of the remaining film fragments was confirmed. After cultivation for two weeks, many irregular holes/pits on the surface of the film due to the colonization of microorganisms were observed by scanning electron microscopy.

Scanning electron micrograph of the surface of PLA film: A. orientalis subsp. orientalis IFO 12362 after 14 d.

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Scanning electron micrograph of the surface of PLA film: A. orientalis subsp. orientalis IFO 12362 after 14 d.
Mechanism of Enzymatic Hydrolysis of Poly(butylene succinate) and Poly(butylene succinate‐co‐L‐lactate) with a Lipase from Pseudomonas cepacia
Authors: Taniguchi Ikuo , Nakano Shigeyuki , Nakamura Tetsuro , El‐Salmawy Ahmed , Miyamoto Masatoshi , Kimura Yoshiharu
Published: February 2003

Enzymatic hydrolysis of poly(butylene succinate) (PBS) and poly(butylene succinate‐co‐L‐lactate) (PBSL) has been studied by using a lipase originated from Pseudomonas cepacia. It has been found that the drawn fibers of PBSL are readily hydrolyzed by the action of the lipase, while those of PBS undergo little enzymatic hydrolysis. Since the polymer films of PBS and PBSL are readily hydrolyzed under the same conditions, the enzymatic hydrolysis should depend not only on the crystallinity but also on the molecular orientation. The molecular weight of the samples gradually decreases with incubation time, because nonspecific hydrolysis occurs on the main chains of both PBS and PBSL even in the absence of lipase. The enzymatic hydrolysis of PBS and PBSL gives 4‐hydroxybutyl succinate (HBS) as the main product with traces of succinic acid and butane‐1,4‐diol together with L‐lactic acid in the case of PBSL. In addition, the hydrolysis rate of the carboxyl end‐capped PBS is much slower than that of the original or hydroxyl end‐capped PBS. These results imply a hydrolysis mechanism involving the preferential exo‐type chain scission from the carboxyl terminals.

Mass remaining of various PBS and PBSL samples as a function of time.

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Mass remaining of various PBS and PBSL samples as a function of time.
Enzymatic Ring‐Opening Polymerization of Oxiranes and Dicarboxylic Anhydrides
Authors: Soeda Yasuyuki , Okamoto Takeshi , Toshima Kazunobu , Matsumura Shuichi
Published: February 2003

Oxiranes, such as glycidyl phenyl ether, benzyl glycidate, glycidyl methyl ether, and styrene oxide, were copolymerized with dicarboxylic anhydrides, such as succinic anhydride, phthalic anhydride, and maleic anhydride, by the action of an enzyme in a stepwise reaction to produce the corresponding polyesters containing some ether linkages having a maximum Mw of 13 500. Oxiranes, such as glycidol and glycidyl phenyl ether, were also homopolymerized and copolymerized with other oxiranes by the enzyme to produce the corresponding polyethers.

Enzymatic polymerization of oxiranes and dicarboxylic anhydrides.

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Enzymatic polymerization of oxiranes and dicarboxylic anhydrides.
Effect of Physicochemical Properties of Polyplexes Composed of Chemically Modified PL Derivatives on Transfection Efficiency In Vitro
Authors: Kimura Tsuyoshi , Yamaoka Tetsuji , Iwase Reiko , Murakami Akira
Published: February 2003

Chemically modified poly‐L‐lysine (PL) derivatives with two essential features, which we have previously reported, have been used to examine the effect of physicochemical properties of their complexes with plasmid DNA on expression efficacy in in vitro gene transfection by osmotic shock procedure. PL derivatives having either Nε‐trimethyl lysine or 13.9% serine residue showed no transfection efficiency. Only when PL was modified in both ways, giving Nε‐trimethyl poly(L‐lysine‐co‐L‐serine), markedly enhanced gene expression was observed. The cellular uptake and localization of DNA in the cells were similar for each cationic polypeptide. The trimethylated polypeptide formed the loosest complexes of DNA among all of the polypeptides used, judging from the loss of EtBr fluorescence. It resulted in more effective DNA release from the complexes by adding heparin, and in the significant gene expression in in vitro transcription/translation systems, as compared with the other polypeptides. The gene transfection efficiency was found to depend on the physicochemical properties of the complexes, such as absence of aggregation, moderate compaction, and easy dissociation, which allow the efficient transcription.

Transfection efficiency of pEGFP‐N1 complexes with (○) PL, (•) PLS, (□) PtmL, and (▪) PtmLS at various C/A ratios.

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Transfection efficiency of pEGFP‐N1 complexes with (○) PL, (•) PLS, (□) PtmL, and (▪) PtmLS at various C/A ratios.
Amphiphilic Lipopeptide Microparticles as Contrast Agents for Medical Ultrasound Imaging
Authors: Cuthbertson Alan , Tornes Audun , Solbakken Magne , Moen Ove , Eriksen Morten
Published: February 2003

In this study we investigated the utility of complementary amphiphilic lipopeptides as a new membrane formulation suitable for the preparation of gas‐filled microbubbles. Through primarily ion pairing and hydrophobic interactions we rationalized that the stacking of synthetic lipopeptides into the surface of microbubbles would make bubble suspensions useful as ultrasound contrast agents. By mixing charged lipopeptides in propylene glycol/glycerol solutions in the presence of a perfluorocarbon gas followed by vigorous shaking, microbubble suspensions were formed in good yield with a size distribution spanning the range 1–7 × 10−6m. The microbubbles were studied in an in vivo model and provided imaging efficacy comparable with conventional ultrasound contrast agents.

Crude sample (before flotation) of Formulation A analyzed at ×40 magnification. The solid bar indicates 10 × 10−6m.

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Crude sample (before flotation) of Formulation A analyzed at ×40 magnification. The solid bar indicates 10 × 10−6m.
Preparation of Polylactide Microspheres Having Positively or Negatively Charged Surfaces
Authors: Arimura Hidetoshi , Ohya Yuichi , Ouchi Tatsuro , Yamada Hideaki
Published: February 2003

The syntheses of polylactides (PLAs) with branched peptide end groups containing reactive (ionic) moieties such as amino or carboxyl groups are described and were used to prepare PLA‐based microspheres (MSs) with positively or negatively charged surfaces. Branched peptides with hydroxyl end groups and four protected amino or carboxyl groups, Boc4‐K3‐OH or Bn4‐E3‐OH, were synthesized, and the hydroxyl group converted to an alkoxide and was used as the initiation site for the ring‐opening polymerization of L‐lactide. Subsequent deprotection gave PLAs end‐capped with branched peptides having four amino or carboxyl groups, respectively (K3‐PLA and E3‐PLA). K3‐PLA and E3‐PLA were converted to K34+‐PLA and E34−‐PLA by acid or base treatment, respectively. MSs with charged surfaces were then prepared using K34+‐PLA or E34−‐PLA as a surfactant [MS(K34+‐PLA) or MS(E34−‐PLA)]. The ionic surface state of the MSs was confirmed by colloidal titration and zeta potential analysis.

SEM image of MSs: MS(K34+‐PLA).

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SEM image of MSs: MS(K34+‐PLA).
Synthesis and Conformation of Star‐Shaped Poly(γ‐benzyl‐L‐glutamate)s on a Cyclotriphosphazene Core
Authors: Inoue Kenzo , Horibe Shigeru , Fukae Makiko , Muraki Takahito , Ihara Eiji , Kayama Hiroshi
Published: February 2003

The preparation of star‐shaped poly(γ‐benzyl‐L‐glutamate)s by the ring‐opening polymerization of N‐carboxy anhydride γ‐benzyl‐L‐glutamate (BLG‐NCA) with hexakis(4‐aminomethylphenoxy)‐ (4) and hexakis(4‐aminophenoxy)cyclotriphosphazenes (6), and the conformation of resulting polymers has been studied. The six amino groups in 4 can initiate the polymerization of BLG‐NCA to give star‐shaped polyglutamates (7) with narrow molecular weight distributions (Mw/Mn = 1.10–1.33). For the polymerization of BLG‐NCA with 6, however, a high ratio of [BLG‐MCA]/[6] was required to obtain star‐shaped polyglutamates (8). The conformation of 7 changed from a β‐sheet form to a right‐handed α‐helix form, depending on the degree of polymerization per chain (DPn/6). The helix content of hexa‐armed poly (γ‐benzyl‐L‐glutamate‐co‐L‐glutamic acid)s (9), prepared by partial hydrolysis of 7, increased significantly compared with that of the corresponding linear analogue (10). As increasing of helix content of 9, the fluorescence spectra of 8‐anilino‐1‐naphthalenesulfonic acid (ANS), a fluorescence probe, shifted to a short wavelength accompanied by the enhancement of intensity, suggesting that star‐shaped polymers are liable to form hydrophobic domains. From these results and the structural feature of the cyclotriphosphazene core, the formation of a 3α‐helix bundle structure of polyglutamates on both sides of the phosphazene ring has been suggested.

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