bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman spectroscopic characteristics of phthalocyanine and naphthalocyanine in sandwich‐type phthalocyaninato and porphyrinato rare earth complexes. Part 5—Raman spectroscopic characteristics of naphthalocyanine in mixed [tetrakis(4‐tert‐butylphenyl)porphyrinato] (naphthalocyaninato) rare earth double‐deckers
Authors: Sun Xuan , Rintoul Llew , Bian Yongzhong , Arnold Dennis P. , Wang Rongming , Jiang Jianzhuang
Published: April 2003

Raman spectra were recorded in the range 400–1800 cm−1 for a series of 15 mixed [tetrakis(4‐tert‐butylphenyl)porphyrinato](2,3‐naphthalocyaninato) rare earth double‐deckers M(TBPP)(Nc) (M = Y; La–Lu except Pm) using laser excitation at 632.8 and 785 nm. Comparisons with bis(naphthalocyaninato) rare earth counterparts reveal that the vibrations of the metallonaphthalocyanine M(Nc) fragment dominate the Raman features of M(TBPP)(Nc). When excited with radiation of 632.8 nm, the most intense vibration appears at about 1595 cm−1, due to the naphthalene stretching. These complexes exhibit the marker Raman band for Nc•− as a medium‐intense band in the range 1496–1507 cm−1, attributed to the coupling of pyrrole and aza stretching, while the marker Raman band of Nc2− in intermediate‐valence Ce(TBPP)(Nc) appears as a strong band at 1493 cm−1 and is due to the isoindole stretchings. By contrast, when excited with radiation of 785 nm that is in close resonance with the main Q absorption band of the naphthalocyanine ligand, the ring radial vibrations at ca 680 and 735 cm−1 for MIII(TBPP)(Nc) are selectively intensified and are the most intense bands. For the cerium double‐decker, the most intense vibration also acting as the marker Raman band of Nc2− appears at 1497 cm−1 with contributions from both pyrrole CC and aza CN stretches. The same vibrational modes show weak to medium intensity scattering at 1506–1509 cm−1 for MIII(TBPP)(Nc) and this is the marker Raman band of Nc•− when thus excited. The scatterings due to the Nc breathings, ring radial vibration, aza group stretchings, naphthalene stretchings, benzoisoindole stretchings and the coupling of pyrrole CC and aza CN stretchings in MIII(TBPP)(Nc) are all slightly blue shifted along with the decrease in rare earth ionic radius, confirming the effects of increased ring–ring interactions on the Raman characteristics of naphthalocyanine in the mixed ring double‐deckers. Copyright © 2003 John Wiley & Sons, Ltd.
Diamond as pressure sensor in high‐pressure Raman spectroscopy using sapphire and other gem anvil cells
Authors: Baonza Valentín García , Taravillo Mercedes , Arencibia Amaya , Cáceres Mercedes , Núñez Javier
Published: April 2003

We propose a new Raman pressure scale based on the shift with pressure of the fundamental Raman band of micrometer‐sized diamonds. First, we confirmed that the pressure slope of the triply degenerate diamond phonon behaves in a similar fashion to that of the bulk. Our measurements were calibrated Raman against the Sm:YAG fluorescence pressure scale up to 5 GPa using a gasketed sapphire anvil cell. The most relevant features regarding the design of the anvil cell are briefly outlined. Measurements were performed under hydrostatic conditions using 4 : 1 methanol–ethanol as pressure‐transmitting medium. The calibration pressures according to the relationship p(GPa) = 0.356[ν(cm−1) − 1332.3] are considered to be accurate within about 0.1 GPa. The convenience of using micrometer‐sized diamonds as pressure sensors in Raman studies using gem anvil devices is demonstrated with several examples. Copyright © 2003 John Wiley & Sons, Ltd.
High‐pressure Raman and infrared spectroscopy of polyacetylene
Authors: Balzaretti Naira Maria , Perottoni Cláudio Antônio , da Jornada João Alziro Herz
Published: April 2003

A systematic study of the high‐pressure (HP) effect on the Raman and infrared (IR) spectra of the cis and trans isomers of polyacetylene (PA) is presented. The experiments were performed in a diamond anvil cell (DAC) up to 9.6 GPa. The pressure‐dependent Raman resonance effect observed for cis‐PA was used to estimate the pressure dependence of the energy gap (Eg) for this isomer. The calculated pressure derivative at zero pressure, dEg/dP = −0.12 eV GPa−1, is the same as that for the trans isomer, estimated from previous results for optical absorption measurements. This is consistent with the idea that the relevant effect of moderated pressures on the PA structure should be the reduction of the interchain distance, which leads to increased interchain coupling that would affect both isomers in a similar way. Furthermore, the IR spectra indicated the onset of structural modifications on both isomers at pressures above 5 GPa. These structural transitions are reversible in the case of trans‐PA and irreversible for cis‐PA. Copyright © 2003 John Wiley & Sons, Ltd.
Freezing/defrosting/frying of sardine fillets. Influence of slow and quick defrosting on protein quality
Authors: García‐Arias M Trinidad , Alvarez‐Pontes Esther , García‐Fernández M Camino , Sánchez‐Muniz Francisco J
Published: April 2003

The effect of sequential freezing/defrosting/frying on protein quality is not well known. With this in mind, fillets of fresh sardine were stored frozen, then thawed, either conventionally at 4 °C in a refrigerator or with the use of a microwave oven, and subsequently deep‐fried. Proximate and amino acid compositions, protein solubility in sodium dodecyl sulphate/β‐mercaptoethanol (SDS/β‐ME), total SH group content and amino acid chemical score were determined. The lowest protein concentration was observed in frozen/4 °C‐thawed sardines (CR), whilst the lowest fat content was found in both fresh/fried sardines (F) and 4 °C‐thawed/fried sardines (CF). Every step of each process studied caused a decrease in cyst(e)ine; the most important loss was recorded in CF samples and in frozen sardines fried without defrosting (Fro‐F). The lowest solubility in SDS/β‐ME and the lowest total SH group content were observed for Fro‐F samples and microwave‐thawed/fried sardines (MF). On the other hand, the lowest chemical score was found for Fro‐F, CF and MF samples. Although weight loss and proximate composition seemed to change less when defrosting sardine fillets using a microwave oven rather than at 4 °C, the results for SDS/β‐ME solubility and total SH group content suggest that a slow defrosting process (refrigerator at 4 °C) is preferable to a much quicker process (microwave oven) for thawing frozen sardine fillets before frying. Copyright © 2003 Society of Chemical Industry
Olive oil extractability index as a parameter for olive cultivar characterisation
Authors: Beltrán Gabriel , Uceda Marino , Jiménez Antonio , Aguilera Maria P
Published: April 2003

Extractability, when applied to the olive oil extraction process is defined as the percentage of oil extracted from the total oil content of the fruit. In this work, extractability index (EI), a new parameter determined in a laboratory oil mill, has been studied for 24 olive (Olea europaea L) cultivars from the Olive Germplasm Bank Collection of Mengibar (Spain). In order to evaluate the genetic variability of this new parameter, the influence of cultivar and tree on EI variability has been analysed in olive fruits collected at the same ripening index. The results indicate that cultivar is the most important variation source. Thus olive oil extractability depends on extraction process variables and cultivar. Extractability index could be used together with pulp oil content (on a dry matter basis) as a parameter for olive cultivar characterisation and selection for breeding projects. Copyright © 2003 Society of Chemical Industry
Oxidative effects in uninfected tissue in leaves of French bean (Phaseolus vulgaris) containing soft rots caused by Botrytis cinerea
Authors: Muckenschnabel Ingo , Schulze Gronover Christian , Deighton Nigel , Goodman Bernard A , Lyon Gary D , Stewart Derek , Williamson Brian
Published: April 2003

Several markers of oxidative processes have been measured in leaves of Phaseolus vulgaris infected with Botrytis cinerea, with the specific objective of investigating changes induced by this necrotrophic pathogen in tissue remote from the lesion. There was a progressive decrease with time in the contents of ascorbic acid (AA) in apparently healthy tissues from infected plants and non‐inoculated plants grown under identical high‐humidity conditions (abiotically stressed controls), and for periods >48 h this decrease was greater in the infected plants. This decline in AA content was accompanied by an elevation in the intensity of the electron paramagnetic resonance (EPR) signal from adducts of the spin trap α‐(4‐pyridyl‐1‐oxide)‐N‐t‐butylnitrone (POBN), a destabilisation of the (monodehydro) ascorbate radical (Asc·) signal in the presence of POBN, and an increase in the ratio of Asc· to AA in samples studied in the absence of the spin trap. These results are consistent with a shift in redox status to more oxidising conditions in apparently healthy tissue of infected plants and indicate the prevalence of chemical processes that are distinctly different from those in uninfected plants. However, no differences in lipid peroxidation products or the single‐peak free radical and Fe(III) (g = 4.27) EPR signals were observed between these tissues distant from the lesions and those from abiotically stressed controls. In addition, the pathogen‐derived sesquiterpene toxin botrydial and a second Mn(II) EPR signal, both of which are associated with Botrytis infection, were not detected in these ‘apparently healthy’ tissues. Copyright © 2003 Society of Chemical Industry
Effect of age of regrowth on chemical composition of chaya (Cnidoscolus aconitifolius) leaves
Authors: Sarmiento‐Franco Luis , Sandoval‐Castro Carlos A , McNab Jim M , Quijano‐Cervera Rosario , Reyes‐Ramirez Raúl R
Published: April 2003

The chemical composition of chaya (Cnidoscolus spp) leaves, as a promissory edible tropical shrub for both humans and animals was evaluated. The chemical composition of C aconitifolius did not differ significantly with age of regrowth, with the exception of ether extractives and the oxalic acid content. Galactose, glucose and xylose were the most important sugars found in the insoluble fraction and, galactose and uronic acid were the main components in the soluble portion of non‐starch polysaccharides (NSP). There was a total content of 197.2 g kg−1 NSP, of which 68.72 and 31.26% corresponded to the insoluble and soluble components respectively. The amino acid composition of C aconitifolius ranged from 0.416 for lysine to 0.641 for valine relative to their contents in soyabean meal. Nevertheless, without exception, the concentrations of all the essential amino acids in C aconitifolius were higher than the corresponding values in alfalfa, a fibrous foodstuff widely acceptable in diets for farm animals. Copyright © 2003 Society of Chemical Industry
Amino acid profiles and protein quality of cooked cassava leaves or ‘saka‐saka’
Authors: Diasolua Ngudi Delphin , Kuo Yu‐Haey , Lambein Fernand
Published: April 2003

Cassava (Manihot esculenta Crantz) leaves form the main source of protein in a diet consisting of processed cassava roots as sole staple food in konzo‐affected areas of the Democratic Republic of Congo. Pounded cassava leaves were hydrolysed and analysed by HPLC before and after cooking to assess amino acid profiles and protein quality. An average of about 58% loss of total protein content was observed in five different cooked samples. The protein content in cassava leaves was high, an average of 285.9 g kg−1 dry weight in the raw and 119.2 g kg−1 dry weight in the cooked samples, but of poor quality, with sulphur amino acids as the most limiting amino acids. Lysine and leucine were also limiting amino acids in some of the raw samples. Lysine, histidine, leucine and isoleucine were limiting amino acids in the cooked samples besides the sulphur amino acids. The consumption of cassava leaves does not compensate the dietary deficiency of sulphur amino acids in the roots that are the staple food in konzo‐affected areas. Sulphur amino acids are essential for detoxification of the residual cyanogens remaining in insufficiently processed cassava roots. Cereals and legumes, as sources of sulphur amino acids and lysine respectively, should be promoted as part of the diet in those areas to prevent the paralytic neuro‐toxico‐nutritional disease konzo among the poor population. Copyright © 2003 Society of Chemical Industry
Compositional and degradative changes during the manufacture of dry‐cured ‘lacón’
Authors: Lorenzo José M , Prieto Bernardo , Carballo Javier , Franco Inmaculada
Published: April 2003

The gross and mineral composition, the main physicochemical parameters, the protein extractability and the proteolytic (nitrogen fractions and free amino acids) and lipolytic (acidity index and free fatty acids) changes were studied throughout the manufacturing process of five batches of dry‐cured ‘lacón’, a traditional Spanish meat product made from the fore‐ham of the pig following a similar technological process to that of dry‐cured ham. The main compositional characteristics of this product are the high NaCl content and the low moisture content at the end of the curing process. The pH remained fairly stable (around 6) throughout the whole process and a fall inawwas observed, reaching very low (0.767 ± 0.052) final average values. It was noted that 76% of the sarcoplasmic and 83% of the myofibrillar proteins became insoluble during the manufacturing process. The values of the different nitrogen fractions increased in a significant manner during manufacture, reaching low final values that indicate that ‘lacón’ undergoes a low level of proteolysis in comparison with other products manufactured by similar technologies. The high NaCl content and the intense dehydration suffered during the manufacturing process appear to be the principal causes of this reduced protein degradation. In accordance with the limited increase in the α‐amino acidic nitrogen during ripening, the total free amino acid content increased slightly but significantly from average values of 4371 mg kg−1dry matter in fresh pieces to average values of 13 020 mg kg−1dry matter in pieces at the end of the ripening process. The profile of free amino acids in the final product was similar to that observed by other authors in dry‐cured ham. The acidity of the fat increased by a factor of five. The final average values (49.9 g oleic acid kg−1) were lower than those determined in dry‐cured ham, which indicates that ‘lacón’ undergoes less lipolysis during the ripening process than dry‐cured ham. C18 : 1, C18 : 2 and C16 were the most intensively released fatty acids during curing. The profile of free fatty acids in the end product was in agreement with that observed by other authors in dry‐cured ham. Copyright © 2003 Society of Chemical Industry
Oxidative stabilization of cold‐pressed sunflower oil using phenolic compounds of the same seeds
Authors: De Leonardis Antonella , Macciola Vincenzo , Di Rocco Antonietta
Published: April 2003

It is known that sunflower seeds are rich in phenols, constituting approximately 1–3 g per 100 g of seeds. The principal phenol is chlorogenic acid (CGA), followed by caffeic acid (CA) and lower quantities of several other compounds. On the contrary, it is known that phenols are present only in trace amounts in cold‐pressed sunflower seed oils. In this study, the possibility of improving the oxidative stability of cold‐pressed sunflower oil is evaluated using phenolic substances constitutive of seeds. Phenols, extracted from two different dehulled sunflower seed samples, were identified, measured and added to a cold‐pressed sunflower oil and compared with butylated hydroxyanisole (BHA), pure CGA and pure CA. Raw phenolic extract (RPE) was composed of CGA exclusively, whereas CA was present only in traces in its free form was not present. On the contrary, hydrolysable phenol acids (HPAs) were constituted prevalently from CA, released by CGA alkaline hydrolysis. The stabilization effect on oil oxidation at 110 °C was evaluated as 41% and 118% for RPE and HPAs respectively with respect to the control. At 30 °C, no significant differences were recorded between the two seed extracts. Their antioxidant effect was lower than that at 110 °C and evaluated to be, on average 13%. In comparison with BHA, at 30 °C, both seed extracts were more effective than this synthetic phenol; at 110 °C, the antioxidant effect of RPE and BHA was similar, whereas HPA was significantly more effective than BHA. In conclusion, this study demonstrates that the phenols present in sunflower seeds can be considered natural antioxidants suitable for stabilizing the oxidation of cold‐pressed sunflower oil, at both low and high temperatures. Copyright © 2003 Society of Chemical Industry
Production of a yogurt‐like product from Lupinus campestris seeds
Authors: Jiménez‐Martínez Cristian , Hernández‐Sánchez Humberto , Dávila‐Ortiz Gloria
Published: April 2003

A Lupinus campestris milk‐like product was obtained with 6.3% protein by using an alkaline thermal treatment. The colour of the suspension showed a greater similarity to cow's milk than to commercial soymilk. To adjust the carbohydrate concentration and induce fermentation, 3% of sucrose and 1.5% of lactose were added. The product was pasteurized and inoculated with a culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp bulgaricus. A lupin yogurt‐like product with pH 4.02, 0.87% lactic acid, and a lactic acid bacteria count (3.2 × 108 CFU ml−1) and viscosity similar to commercial cow's milk yogurt was obtained. The amino acid composition of the proteins in the lupin milk and yogurt products had a good balance, with the exception, as in other legumes, of the sulphur‐containing amino acids. Sensory evaluation indicated that the product was well accepted by consumers. These results offer a good possibility for the utilization of this legume in human nutrition through the elaboration of products that are analogous to others already present in the commercial market. Copyright © 2003 Society of Chemical Industry
A rapid non‐destructive method for fish quality control by determination of smell intensity
Authors: Gelman A , Drabkin V , Glatman L
Published: April 2003

The ‘Cosmos’ instrument (Japan) was applied to the evaluation of fish quality in six species of different origins, by determination of smell intensity. Pond‐raised fish (trout, carp, silver perch, tilapia, barramundi) were stored in ice for 4–5 weeks and frozen/thawed mackerel was kept at room temperature for 74 h. The fish quality was examined by organoleptic assessment, by determination of smell intensity and by tests of the chemical (total volatile basic nitrogen, hypoxanthine and histamine) and dielectric (Torrymeter) properties. Strong correlation was found between the organoleptic and ‘Cosmos’ results, whereas the data from the chemical and Torrymeter analyses were relatively poorly correlated with the sensory evaluation and ‘Cosmos’ data. Thus the application of the ‘Cosmos’ instrument for objective quantitative evaluation of fresh and chilled fish quality by determination of smell intensity seems practicable. The ‘Cosmos’ instrument is hand‐held and portable as well as being rapid and non‐destructive in operation; therefore it could be used for evaluation of fresh and chilled fish in the field and on board fishing vessels. Copyright © 2003 Society of Chemical Industry
The mouth‐feel properties of grape and apple proanthocyanidins in a wine‐like medium
Authors: Vidal Stéphane , Francis Leigh , Guyot Sylvain , Marnet Nathalie , Kwiatkowski Mariola , Gawel Richard , Cheynier Véronique , Waters Elizabeth J
Published: April 2003

A range of structurally defined apple and grape proanthocyanidins was isolated in sufficient amount to carry out a formal sensory descriptive analysis study. Purified proanthocyanidin fractions differed in chain length, degree of galloylation and epigallocatechin content. Astringency attributes of the preparations in a model wine medium were rated while the fractions were held in the mouth and after expectoration. The degree of polymerization appeared to be the variable that discriminated among the fractions to the greatest extent. It affected both the overall astringency and the different individual astringency attributes, with increased ‘drying’, ‘chalky’, ‘adhesive’ and ‘pucker’ characters correlating with increasing chain length. A rougher sensation with increased ‘coarseness’, ‘drying’ and ‘chalkiness’ correlated with an increased degree of galloylation of the fractions. The presence of epigallocatechin units in the proanthocyanidin tended to lower the ‘coarse’ perception. Copyright © 2003 Society of Chemical Industry
Evaluation of fermentation and aerobic stability of wet brewers' grains ensiled alone or in combination with various feeds as a total mixed ration
Authors: Nishino Naoki , Harada Hiroaki , Sakaguchi Ei
Published: April 2003

Wet brewer's grains (BG; 200 g kg−1 dry matter(DM)) were ensiled alone or in combination with various dry feeds as a total mixed ration (TMR; 540 g kg−1 DM) in laboratory silos. Ensilage was stopped at 40 days (experiment 1) or at 5, 20, 40 and 60 days (experiment 2) after storage. The composition of soluble sugars and the profiles of fermentation products were determined. The 60 day silages were subjected to aerobic deterioration and changes in silage temperature were recorded for 7 days. A rapid pH fall coupled with accelerated lactic acid production was observed in BG silage; soluble sugars, mainly composed of maltose and raffinose, completely disappeared within 5 days of ensiling. Prolonged storage, however, decreased lactic acid concentration and increased acetic acid greatly. Appreciable amounts of propionic acid and 1‐propanol were also produced in BG silage in the late stages of fermentation. When TMR silage was made, the decline in pH and the increase in lactic acid were delayed due to the low moisture content. Acetic acid production was enhanced from the beginning of storage, and mannitol accumulated in TMR silage. Yeast numbers were lower in TMR than in BG silage, but the changes were limited in the late stages of fermentation. When exposed to air, the temperature of BG silage increased after 3 days, whereas that of TMR silage appeared stable during the 7 days test. The results indicate that BG is a suitable by‐product for ensiling and, when ensiled with various feeds as a TMR, improved stability against aerobic deterioration can be expected. Copyright © 2003 Society of Chemical Industry
Effect of industrial processing on desert truffles Terfezia claveryi Chatin and Picoa juniperi Vittadini): proximate composition and fatty acids
Authors: Murcia M Antonia , Martínez‐Tomé Magdalena , Vera Ana , Morte Asunción , Gutierrez Almudena , Honrubia Mario , Jiménez Antonia M
Published: April 2003

Our objectives were to investigate the proximate composition of two desert truffles (Terfezia claveryi Chatin and Picoa juniperi Vittadini) and to determine the effects of freezing and canning on proximate composition. The moisture content of T claveryi and P juniperi was 730.9 g kg−1 and 637.8 g kg−1 respectively; ash was 42.5 g kg−1 and 82.1 g kg−1 respectively; protein was 159.5 g kg−1 and 225.4 g kg−1 respectively; lipids were 69.5 g kg−1 and 199.4 g kg−1 respectively; fibre was 83.2 g kg−1 and 130.4 g kg−1 respectively; and carbohydrates were 645.5 g kg−1 and 366.6 g kg−1 respectively. The fatty acids composition showed high quantities of linoleic acid 18:2 (45.4% in T claveryi and 53.0% in P juniperi), the rest of the fatty acids in decreasing order were 16:0 > 18 : 1 > 18 : 3 18 : 0 + 22 : 0 > 20 : 0 + 24 : 0 > 14 : 0 + 22 : 1 > 15 : 0 + 16 : 1 + 17 : 0 + 21 : 0 in T claveryi and 18 : 1 > 16 : 0 > 18 : 0 + 18 : 3 + 16 : 1 + 20 : 0 + 22 : 1 > 14 : 0 + 24 : 0 > 15 : 0 + 17 : 0 + 22 : 0 in the P juniperi. Little loss of ash, protein and lipids was observed as a result of industrial processing (p < 0.05). Copyright © 2003 Society of Chemical Industry
Effect of ‘Californian’ process on the texture of Hojiblanca olive (Olea europaea L) harvested at different ripening stages
Authors: Georget Dominique MR , Smith Andrew C , Waldron Keith W , Rejano Luis
Published: April 2003

The tensile properties of the skin and the flesh of the table olive, ‘Hojiblanca’ produced in Spain, which underwent the ‘Californian style’ process (step 1: brine; step 2: lye; step 3: heat and brine), were determined. The stiffness and strength of the skin were significantly higher than those of the flesh at all processing stages. The results showed that step 2 resulted in a decrease in strength of the skin. The strength of the flesh increased after step 2 but decreased after step 3 due to heat treatment at 121 °C for 30 min. These changes in strength varied with the degree of maturity for the flesh. An increase in strain at failure was observed in the skin after step 2, whereas no significant changes were detected in the flesh. A decrease in strain at failure was observed in the skin and the flesh further to step 3. After step 2, the stiffness of the skin decreased significantly, whereas that of the flesh increased, the latter decreasing with increasing degree of maturity. The largest effects were in the strength and stiffness of the skin after sodium hydroxide treatment affecting their wax content. Maturity has a larger effect on flesh than on skin mechanical properties. Copyright © 2003 Society of Chemical Industry
Application of electron‐beam irradiation pasteurization of ground beef, from steers fed vitamin E fortified diets: microbial and chemical effects
Authors: Poon Patty WB , Wong Peter YY , Dubeski Paula , Durance Tim D , Kitts David D
Published: April 2003

The effects of vitamin E supplementation of diets and electron‐beam irradiation (EBI) processing of ground beef patties on microbial and chemical qualities were investigated during 21 days of storage at 4 °C. Oxidative damage to lipids induced by EBI in ground beef patties containing different fat contents was first determined at 3 day intervals throughout a 7 day storage period at 4 °C. Significantly (P ≤ 0.05) higher values for thiobarbituric acid reactive substances (TBARS) were detected in beef patties of higher fat content (ie at 17 and 30%), which was further enhanced by irradiation at 5 kGy. Since lipid oxidation proceeded to a greater extent in beef patties with higher fat levels, ground beef patties of 30% fat were prepared from steers fed basal (diet I) or basal + 500 IU (diet II) of the antioxidant (vitamin E) supplemented diets. Plasma vitamin E concentrations in cattle fed diets I and II were 1.58 ± 0.42 µg ml−1 and 2.49 ± 0.40 µg ml−1 respectively. Patties were processed with three doses (2, 5, or 10 kGy) of EBI and compared with non‐irradiated patties. Microbial indices monitored at 3 day intervals included total aerobic plate count, psychrotrophic counts, and total coliform and Escherichia coli counts. Bacterial growth in ground beef patties stored at 4 °C was significantly (P ≤ 0.05) reduced by EBI at 2 kGy dose. Complete inhibition of bacteria occurred at 5 kGy or higher (P ≤ 0.05) dosage of EBI over 21 days of storage at 4 °C. Quality indices monitored at 3 day intervals throughout a 21 day storage (4 °C) study involving 30% fat ground beef patties made from steers fed vitamin E supplemented diets I and II included TBARS and colour. Results indicated that irradiation at the highest dosages was associated with higher (P ≤ 0.05) TBARS values, which in turn corresponded to lower linoleic acid content. With all three levels of irradiation, Hunter a values of beef patties decreased (P ≤ 0.05) significantly. Lipid oxidation was significantly (P ≤ 0.05) retarded in stored beef patties derived from cattle fed vitamin E (diet II). Copyright © 2003 Society of Chemical Industry
Supercritical carbon dioxide extraction of pelletized Jalapeño peppers
Authors: del Valle José M , Jiménez Marisol , Napolitano Pablo , Zetzl Carsten , Brunner Gerd
Published: April 2003

The effects of process pressure (220–500 bar) and temperature (35–65 °C) on yield and extract quality of pelletized Jalapeño peppers (Capsicum annuum L) treated with supercritical carbon dioxide (ScCO2) were studied. Compaction was inadequate when using whole air‐dried pepper flakes conditioned to high moisture as raw material, which resulted in high porosity pellets and low bed densities. Thus, reference pellet samples were produced from Jalapeño pepper flakes that were finely ground and conditioned to low moisture. Pressures ≥290 bar did not affect cumulative extraction of reference pellet samples at 45 °C. On the other hand, the extraction rate of reference pellet samples at 360 bar increased with process temperature, as a result of increments in solubility, improvements in mass transfer properties, and/or improvements in solute desorption from the solid matrix. With regard to pretreatment, finely ground pepper samples were extracted in half the time of reference pellets (120 versus 270 min) at 360 bar and 45 °C; increasing sample moisture prior to pelletization increased extraction yield; and decreasing particle size prior to pelletization increased extraction rate slightly. These results suggest that sample moisture is partially co‐extracted by ScCO2, and that the extraction rate of pelletized Jalapeño peppers is controlled by internal mass transfer mechanisms. Chlorophyllian pigments were removed in the final stages of the extraction process. Furthermore, pigment extraction increased with process pressure at 45 °C, and it increased slightly with process temperature at 360 bar. On the other hand, the concentration of capsaicinoids in extract samples remained constant during ScCO2 extraction. Copyright © 2003 Society of Chemical Industry
Boron concentrations in selected foods from borate‐producing regions in Turkey
Authors: Simsek Atilla , Velioglu Y. Sedat , Coskun A. Levent , Sayli B. Sitki
Published: April 2003

As part of a large‐scale programme to investigate the health effects of exposure to borate minerals in Turkey, boron concentrations in vegetables, fruits and some other foods were determined. From all borate‐producing regions of the country, 22 species of fruit, 17 species of vegetable, 12 species of cereal, legume and oilseed, three species of herbs and six types of other food were collected in 1999 and analysed for boron concentrations using the Azomethine H method. The results were compared with 37 types of food collected from areas well distant from the borate‐producing areas. The total number of samples evaluated was 420. Pistachio (67.0 mg kg−1) had the highest concentration of boron, followed by grape leaf (60.48 mg kg−1), sour cherry (57.03 mg kg−1), quince (38.78 mg kg−1), peach (34.49 mg kg−1), grape (20.70 mg kg−1), green beans (19.49 mg kg−1), unripe peach (18.92 mg kg−1) and parsley (10.24 mg kg−1) from the borate‐producing regions. A large number of foods contained boron at higher concentrations than those reported in the literature, most probably due to the high boron content of these Turkish soils. According to the results of t‐tests, the area itself does not have a significant effect (p > 0.05) on boron concentration in all foods evaluated so far. Copyright © 2003 Society of Chemical Industry
GA‐based prediction of antenna radiation patterns from planar near‐field samples
Authors: Pérez J. R. , Basterrechea J.
Published: April 2003

In this paper, a genetic‐algorithm (GA) based approach for predicting the far‐field pattern of an antenna under test (AUT) from planar near‐field samples is presented. The method reconstructs the antenna radiation pattern from an optimized equivalent model of the AUT consisting of electric and magnetic short dipoles. Numerical results showing predicted far‐field patterns are reported and discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 235–236, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10880
Hybrid FDTD/AUTOCAD® method for the analysis of BOR horns and reflectors
Authors: Yang Zijiang , Chen Yinchao , Yu Wenhua , Mittra Raj
Published: April 2003

Horns and reflector antennas, which are bodies of revolution (BORs), find widespread use in the areas of communication and radar systems. In this work, we present a highly efficient, BOR finite‐difference time‐domain (BOR/FDTD) technique for the analysis of these antennas. This approach allows us to employ a 2D finite‐difference lattice that projects a 3D Yee cell in the cylindrical coordinates (ρ, ϕ, z) onto the (ρ, z) plane, and substantially reduces the computational burden in the process. To analyze arbitrary BOR geometries, we develop a mesh generator that uses the commercial design tool AutoCAD® to systematically generate the geometrical and material input files for the BOR/FDTD solver. We also apply a near‐to‐far‐field transformation, based on a line integral along a contour of equivalent electric and magnetic currents, to evaluate the radiation patterns of these antennas in a highly efficient manner. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 236–243, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10881
Triple‐frequency rectangular‐ring slot antennas fed by CPW and microstrip line
Authors: Chen Jin‐Sen , Lin Shun‐Yun
Published: April 2003

In this paper, a design of a rectangular‐ring slot antenna for obtaining triple‐frequency operation using a coplanar waveguide (CPW) feed or microstrip‐line feed is presented. We introduce three concentric rectangular‐ring slots whose perimeters easily control the three respective operating frequencies. Details of the proposed design are investigated by experimental as well as theoretical studies. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 243–246, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10882
Efficient analysis of arbitrarily shaped microstrip structures
Authors: Ge Yuehe , Esselle Karu P.
Published: April 2003

A new, efficient method of moments (MoM) is developed for accurate, full‐wave analysis of microstrip components and circuits. The new method is applied for the analysis of a two‐gap filter. The new method is found to be as accurate as conventional moment methods, and also significantly faster. It has a good potential for use in the microstrip design of CAD tools. The key to the high efficiency of the new MoM is the use of a set of newly developed closed‐form Green's functions, which allow the computation of the MoM matrix elements without any numerical integration when using the RWG function as the basis functions. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 246–248, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10883
Compact microstrip slot antenna for broadband operation
Authors: Paulson Manju , Kundukulam Sona O. , Aanandan C. K. , Mohanan P. , Vasudevan K.
Published: April 2003

An arrow‐shaped microstrip antenna with a pair of narrow slots embedded near the non‐radiating edges gives wide impedance bandwidth. The experimental and simulated (IE3D) results show that antenna bandwidth is ∼3.5 times that of a conventional patch with the added advantage of reduced antenna size. The radiation characteristics are found to be uniform throughout the operating band. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 248–250, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10884
Analysis of terahertz detection with a 2D hot‐electron quantum well detector
Authors: Huo Y. , Taylor G. W.
Published: April 2003

The operation of a previously proposed terahertz (THz) detector is formulated in detail. The detector is based on the hot‐electron effect of the 2D electron gas (2DEG) in the quantum well (QW) of a GaAs/AlGaAs heterostructure. The interaction between the THz radiation and the 2DEG, the current enhancement due to hot‐electron effect, and the noise performance of the detector are analyzed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 250–255, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10885
Spectral properties of a periodic N × N network of interconnected transmission lines
Authors: Le Floc'h Laurence , Quintard Véronique , Favennec Jean‐François , Boucher Yann
Published: April 2003

We investigate theoretically and experimentally the spectral behavior of discrete 2D structures of finite size, made of microwave lines periodically interconnected by four‐port networks. Their spectral responses, including forbidden bands, are expressed analytically as functions of a reduced set of parameters, all related to the properties of a unit cell. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 255–259, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10886
Backward waves and negative refraction in uniaxial dielectrics with negative dielectric permittivity along the anisotropy axis
Authors: Belov P. A.
Published: April 2003

Veselago medium (also called double negative material, backward medium, left‐handed medium) is a medium with both negative isotropic dielectric permittivity and permeability. It has the effect of backward waves with negative (anomalous) refraction, in contrast to the usual forward waves with normal refraction in normal isotropic dielectrics and/or magnetics. In this paper, examples of the existence of backward waves (with respect to the interface) without negative refraction, and negative refraction without backward waves in uniaxial dielectrics with negative permittivity along the anisotropy axis, are presented. Considering these examples increases the possibility of designing backward wave materials and negative refraction materials without using magnetic media. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 259–263, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10887
A highly efficient and accurate procedure for semi‐anechoic chamber analysis using circuital techniques
Authors: Nuño L. , Balbastre J. V. , Quesada F. D.
Published: April 2003

This paper reports on a new method for the determination of the performance qualities of a semi‐anechoic chamber used for electromagnetic compatibility measurements. This approach, based on highly efficient and accurate circuital techniques, provides very good results on low‐cost desktop computers in the frequency range 30–300 MHz. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 263–265, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10888
Gain clamped L‐band EDFA using a fiber Bragg grating in two stage configuration
Authors: Harun S. W. , Tamchek N. , Ahmad H.
Published: April 2003

A gain clamping technique for the long‐wavelength‐band erbium‐doped fiber amplifier (L‐band EDFA) is presented. It uses two circulators and a fiber Bragg grating (FBG) to route a backward amplified spontaneous emission (ASE) from a second‐stage amplifier and launch it back into the first stage. The use of a broadband (BB) FBG has shown a better gain clamping effect, compared to a narrowband (NB) FBG. The amplifier gain for the BB FBG set up is clamped at 15.0 dB with a gain variation of less than 0.1 dB for an input power as high as −5 dBm. The use of a BB FBG has also flattened the gain spectrum. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 265–266, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10889
Novel periodically loaded ridged waveguide resonators
Authors: Goussetis George , Budimir Djuradj
Published: April 2003

Novel periodically loaded E‐plane waveguide resonators are presented in this paper. The proposed resonators make use of the slow‐wave effect in order to achieve significantly increased loaded Q values for resonators of constant volume, as compared to their homogeneous counterparts, without introducing any complexity in the fabrication process. Numerical and experimental results are presented to validate the argument. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 266–268, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10890
Propagation of a femtosecond laser pulse through a dispersion‐free spatially‐chirped medium
Authors: Hovhannisyan D. L. , Stepanyan K. G. , Kalayjian Z. K.
Published: April 2003

The analytical solution of a wave equation that describes the propagation of a femtosecond laser pulse in a dispersion‐free finite‐length spatially chirped medium with 1D periodic inhomogeneity is presented. Such media are important to modern optics and are found in holograms, lasers, Bragg reflectors, compressors, and other applications. FDTD numerical modeling confirms the validity of our analytic results. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 269–273, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10891
Clock recovery from degraded signals at high repetition rates using a two‐ring injection mode‐locked fiber ring laser
Authors: Wang Zhaoxin , Wang Tong , Huo Li , Lou Caiyun , Gao Yizhi
Published: April 2003

Clock recovery from degraded signals at 10, 20, and 40 Gb/s data rates was achieved using a two‐ring injection mode‐locked fiber‐ring laser based on 10‐GHz bandwidth components. No pattern effect was observed in these experiments. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 273–276, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10892
An experimental implementation of resistive plates to enhance the performance of the mobile base station antennas
Authors: Chou Hsi‐Tseng , Wang Jing‐Song , Hsiao Yu‐Ting
Published: April 2003

In mobile communications, irregular handover and undesired interference, caused by wide inter‐sector coverage overlapping and the antenna's side‐lobe radiation, are improved by the application of resistive plates. This paper experimentally examines the characteristics of resistive plates and their design and implementation in order to reduce interference and enhance performance by guiding the power from overlapping regions to the main‐beam regions of each sector. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 276–280, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10893
Optimized grids for the wavelet‐analysis of generalized T‐junctions
Authors: Schneider Guido , Heyen Johann , Jacob Arne F.
Published: April 2003

Generalized microstrip T‐junctions are investigated by means of a method of moments (MoM) wavelet analysis. The focus is on the optimization of the grid for both efficiency and accuracy. Numerical results for different geometrical parameters show that, in contrast to simpler junctions, this grid has to be designed very carefully. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 280–282, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10894
Techniques to increase gain and impedance bandwidth of a cross‐aperture coupled patch antenna
Authors: Chung Kwok L. , Mohan Ananda S.
Published: April 2003

A broadband high‐gain single‐feed cross‐aperture coupled patch antenna is presented in this paper. The measured results confirm that the antenna is capable of a 14.4% impedance bandwidth (VSWR ≤ 2), 3% of 3‐dB axial‐ratio bandwidth, and 17.4% of gain (>8 dBic) bandwidth with a mean gain level of 9.3 dBic. The techniques for obtaining high gain and broad impedance bandwidth as well as the effects on aperture size are discussed. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 283–286, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10895
Linearity vs. Q‐factor of loads for RF amplifiers
Authors: Kim Jin‐pil , Park Seong‐su , Lee Sang‐gug
Published: April 2003

This paper analyzes and verifies that RF amplifier linearity as well as gain depend significantly on the quality of the output matching components or the loads (especially the inductor). Two amplifiers with off‐ and on‐chip matching circuits are built and compared. Measurement results show that a driver amplifier with off‐chip reactive output matching provides better linearity and gain of 3.6 dB and 1.6 dB, respectively, as compared to that of the amplifier with on‐chip matching. The amplifiers are implemented for 2.4‐GHz operation based on 0.35‐μm CMOS technology. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 286–288, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10896
Electrically tunable dispersion compensator based on nonlinearly chirped fiber Bragg grating
Authors: Yinying Zhang , Dexiang Wang , Enguang Dai , Deming Wu , Anshi Xu
Published: April 2003

A new prototype of a compact and power‐efficient tunable dispersion compensator is demonstrated. To our acknowledge, this is the first time a tunable dispersion compensator using nonlinearly chirped fiber Bragg grating, coated with on‐fiber uniform metal heater, has been realized. A remarkable degree of dispersion tunability, as much as approximately 800 ps/nm, has been demonstrated. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 288–292, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10897
Numerical study of a Gaussian beam propagating in media with negative permittivity and permeability by using a bidirectional beam propagation method
Authors: Lu Jun , He Sailing
Published: April 2003

Gaussian beam propagation in structures containing meta‐materials with negative permittivity and negative permeability is numerically studied by using a bidirectional wide‐angle finite‐difference beam propagation method. Illustrative and quantitative views are given for various anomalous behaviors, such as the negative angle of refraction, beam refocusing, arbitrarily thin distributed Bragg reflector, and negative lateral shift of the reflected beam from a grounded slab, by a Gaussian beam propagating in some meta‐material structures. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 292–296, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10898
Almost uniformly excited arrays
Authors: Rodríguez J. A. , López P. , Ares F. , Moreno E.
Published: April 2003

Antenna arrays with good performance that are uniformly excited except for the amplitudes and/or phases of a minority of elements can be synthesized using genetic algorithms. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 297–300, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10899
Wideband dielectric resonator‐loaded suspended microstrip patch antennas
Authors: Gupta Vijay , Sinha Sumit , Koul Shiban K. , Bhat Bharathi
Published: April 2003

Experimental investigations of rectangular and circular suspended microstrip patch antennas with dielectric resonator loading at X‐band are reported. With loading, enhanced impedance bandwidth to about 18% is achieved in a single circular patch as compared to 13% for a single rectangular patch. In both cases, with loading, there is practically no change in the respective 3‐dB beam widths of the radiation patterns in E‐ and H‐planes. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 37: 300–302, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10900