bluuebunny/crossref_metadata_2025 huggingface dataset:
HF fades caused by multiple wave fronts detected by a dipole antenna in the ionosphere
Authors: James H. G. , Gillies R. G. , Hussey G. C. , Prikryl P.
Published: August 2006

An experiment on transionospheric HF propagation was carried out in 1978 using a dedicated ground transmitter at Ottawa and the sounder receivers of the ISIS 1 and ISIS 2 spacecraft. This paper deals with resulting data from ISIS 2 at 1400 km altitude. Fade frequencies of one to a few hertz on 9.303‐MHz fixed‐frequency carrier signals were measured and were found to be confined to satellite locations between about 3° and 20° equatorward of the transmitter. The majority of the fades were of the Faraday type, involving ordinary (O) and extraordinary (X) wave components. There was also a smaller number of single‐mode fades interpreted as a beat interference between two O‐mode or two X‐mode rays that take different routes to the spacecraft. Rays traced through model ionospheric density distributions based on tomographic data show that rays launched toward the equator are more susceptible to focusing by latitudinal periodicity than rays launched toward the pole. Such refractive effects can produce two same‐mode rays with equal intensities and different propagation directions. Swept‐frequency ionograms interleaved with fixed‐frequency measurements have also been used to model density distributions in altitude and latitude. These distributions were used iteratively with three‐dimensional ray tracing to find rays that connected the transmitter with the position of the satellite at times of interest along its path. Faraday fade rates thus predicted agree with those observed equatorward of the transmitter. Geometric optics cannot account for observed X‐mode to O‐mode signal ratios of at least 10 dB in other parts of the passes, ruling out deep Faraday fades. This research supports planning for coordinated ground‐space radio experiments in the upcoming Enhanced Polar Outflow Probe satellite mission.
Complex fault patterns, transtension and structural segmentation of the Lofoten Ridge, Norwegian margin: Using digital mapping to link onshore and offshore geology
Authors: Wilson Robert W. , McCaffrey Kenneth J. W. , Holdsworth Robert E. , Imber Jonathan , Jones Richard R. , Welbon Alastair I. F. , Roberts David
Published: August 2006

An integrated onshore‐offshore study involving regional to outcrop‐scale fault analysis is used to develop a self‐consistent structural model for transtension along the Lofoten Ridge. The Lofoten‐Vesterålen archipelago (LVA) is a segmented basement high showing distinct lateral variations in trend, deformational style, and structural complexity. This study investigates whether segmentation can be linked to differences in the obliquity of preexisting structures relative to plate movement vectors. Regional analysis of fault lineament patterns using Geographic Information Systems (GIS) reveals that the LVA can be subdivided into a series of distinct lineament domains. These domains are closely coincident with changes in ridge trend and variations in structure within offshore models derived from seismic reflection studies. Digital field mapping and spatial analysis of faulting in the north Lofoten reveal that multimodal faulting is dominated by transtensional dip‐slip and oblique‐slip movements which are comparable to analogue models where the ridge axis is 30° oblique to regional extension. The overall change in fault orientation, fault geometry, and deformation style are consistent with models for transtension where the ridge‐bounding structure becomes increasingly oblique to regional extension. Previously identified transfer zones simply reflect segment domain boundaries and are not reactivating basement structures. This model is a possible analogue for other orthogonal and oblique rift structures on the Norwegian and other margins.
Identification of runoff generation spatial distribution using conventional hydrologic gauge time series
Authors: Martina Mario L. V. , Entekhabi Dara
Published: August 2006

As traditional hydrologic measurements, stream stage and precipitation gauge observations often have the benefit of long records. Even though they have good value for calibrating conceptual models of basin hydrologic units, they are not adequate for understanding basic (spatial) physical processes such as rainfall‐runoff transformation. Stream discharge estimated from stage measurements represents the aggregate outflow from the catchment draining at the measurement location. Processes governing runoff nevertheless vary considerably across the terrain. Hillslope recharge‐discharge patterns, surface water–groundwater interaction, and the emergence of riparian zones are examples of processes that vary across the basin. Their dynamics are not evident in stream gauge hydrographs. In this paper a methodology is introduced that allows the extraction of some spatial information from the analysis of precipitation and discharge time series. The marginal distribution of available soil water storage across the basin is evident in the subtle and nonlinear covariations between storm precipitation and storm runoff volumes in the time series. The approach is nonparametric in that it does not assume nor require a conceptual hydrologic model. The methodology is introduced and tested using both synthetic and observed gauge records. A scalar and nondimensional measure of hydrologic complexity is introduced to characterize the spatial variability of basin rainfall‐runoff response behavior.
The disappearance of anomalous protons at Voyager 1 and Voyager 2 in the outer heliosphere between 1998 and 2002
Authors: Webber W. R. , McDonald F. B. , Cummings A. C. , Stone E. C. , Heikkila B. , Lal N.
Published: August 2006

In 1998 and 1999 at V1 and V2 in the outer heliosphere between 55 and 75 AU, large intensities of anomalous H were observed with a peak in the differential energy spectrum at ∼25 MeV. Subsequently, in 2000 and 2001 when these spacecraft were 5–10 AU further out, these intensities were greatly reduced by 11‐year modulation effects, so that by the beginning of 2002 anomalous H had completely disappeared beneath the E1.0 spectrum of galactic H at low energies. The modulation between 1998 and 2002 produced intensity changes of galactic H similar to those observed at the Earth in the same time period except that the changes at V1 and V2 were much smaller. The intensity change at V2 was also larger than that at V1. For anomalous H, however, the intensity changes at V1 and V2 were a factor of 10–20 times larger than those for galactic H, so that by the end of 2001 the anomalous H intensities were less than 1% of their 1998 values. Also, during one time period in late 2001 there was a large reduction of anomalous H at both V1 and V2 with no corresponding change in galactic H. These different intensity changes between galactic and anomalous H provide an insight into particle transport, drift, and acceleration processes in the region near the heliospheric termination shock, which is located just beyond V1. Radial gradient comparisons in 1998 and also at the times of reduced anomalous H intensities imply that most of the intensity reduction of anomalous H apparently occurred at ∼90 AU or beyond. This could indicate source changes in the anomalous H spectra but most likely is a measure of changes in the “connection” between V1 and V2 and the source region, such as might be caused by changing drift patterns and particle entry into the heliosphere.
One-dimensional arrays of nanoshell dimers for single molecule spectroscopy via surface-enhanced raman scattering
Authors: Zhao Ke , Xu Hongxing , Gu Baohua , Zhang Zhenyu
Published: August 2006

The optical properties of one-dimensional arrays of metal nanoshell dimers are studied systematically using the T-matrix method based on Mie theory, within the context of surface enhanced Raman scattering (SERS). It is shown that the local electromagnetic enhancement can be as high as ∼4.5×1013 for nanoshell dimer arrays with optimal geometry, and sensitive tunability in the resonant frequency can be gained by varying the geometrical parameters, making such structures appealing templates for SERS measurements with single molecule sensitivity. The extraordinarily high enhancement is attributed to a collective photonic effect constructively superposed onto the intrinsic enhancement associated with an isolated nanoshell dimer.
Large dielectric susceptibility associated with proton transfer in a supramolecular structure of chloranilic acid and 5,5′-dimethyl-2,2′-bipyridine
Authors: Kumai Reiji , Horiuchi Sachio , Okimoto Yoichi , Tokura Yoshinori
Published: August 2006

A 1:1 adduct of chloranilic acid with 5,5′-dimethyl-2,2′-bipyridine, in which two kinds of molecules are connected by infinite hydrogen bond chains, exhibits a distinct dielectric phase transition when cooled. Below Tc(=318K) the hydrogen atoms participating in hydrogen bonding undergo long-range ordering and form an antiferroelectriclike state, taking a single minimum potential in the high-temperature phase (T>Tc) due to the bifurcate hydrogen bond system. The proton-transfer phenomenon was clearly observed by electron density distribution analysis using a maximum entropy method of synchrotron x-ray diffraction data.
Theoretical assessment of the elastic constants and hydrogen storage capacity of some metal-organic framework materials
Authors: Samanta Amit , Furuta Terumi , Li Ju
Published: August 2006

Metal-organic frameworks (MOFs) are promising materials for applications such as separation, catalysis, and gas storage. A key indicator of their structural stability is the shear modulus. By density functional theory calculations in a 106-atom supercell, under the local density approximation, we find c11=29.2GPa and c12=13.1GPa for Zn-based MOF 5. However, we find c44 of MOF-5 to be exceedingly small, only 1.4GPa at T=0K. The binding energy Eads of a single hydrogen molecule in MOF-5 is evaluated using the same setup. We find it to be −0.069to−0.086eV∕H2 near the benzene linker and −0.106to−0.160eV∕H2 near the Zn4O tetrahedra. Substitutions of chlorine and hydroxyl in the benzene linker have negligible effect on the physisorption energies. Pentacoordinated copper (and aluminum) in a framework structure similar to MOF-2 gives Eads≈−0.291eV∕H2 (and −0.230eV∕H2), and substitution of nitrogen in benzene (pyrazine) further enhances Eads near the organic linker to −0.16eV∕H2, according to density functional theory with local density approximation.
Viscoelasticity of mono- and polydisperse inverse ferrofluids
Authors: Saldivar-Guerrero Ruben , Richter Reinhard , Rehberg Ingo , Aksel Nuri , Heymann Lutz , Rodriguez-Fernández Oliverio S.
Published: August 2006

We report on measurements of a magnetorheological model fluid created by dispersing nonmagnetic microparticles of polystyrene in a commercial ferrofluid. The linear viscoelastic properties as a function of magnetic field strength, particle size, and particle size distribution are studied by oscillatory measurements. We compare the results with a magnetostatic theory proposed by De Gans et al. [Phys. Rev. E 60, 4518 (1999)] for the case of gap spanning chains of particles. We observe these chain structures via a long distance microscope. For monodisperse particles we find good agreement of the measured storage modulus with theory, even for an extended range, where the linear magnetization law is no longer strictly valid. Moreover we compare for the first time results for mono- and polydisperse particles. For the latter, we observe an enhanced storage modulus in the linear regime of the magnetization.
Mobility of O+ in He and interaction potential of HeO+
Authors: Danailov Danial M. , Brothers Renee , Viehland Larry A. , Johnsen Rainer , Wright Timothy G. , Lee Edmond P. F.
Published: August 2006

New experimental measurements are reported for the mobility of O+ ions in He gas at 300K. The accuracy of these new values is estimated as ±2.5%, which allows them to serve as a stringent test of a new ab initio potential that we have calculated using the RCCSD(T) method. We employed the aug-cc-pV5Z basis set with counterpoise corrections and took spin-orbit coupling into account. The present experimental values lie below the calculated ones, but the difference becomes statistically significant only at moderate and high values of the ratio of the electric field strength to the gas number density; even there they are only marginally significant.
State-resolved thermalization of singlet and mixed singlet-triplet states of CH2
Authors: Komissarov Anatoly V. , Lin Ao , Sears Trevor J. , Hall Gregory E.
Published: August 2006

The role of mixed states in the collision-induced thermalization, intersystem crossing, and reactive loss of CH2 (ãA11) has been monitored using Doppler-resolved transient frequency modulation absorption spectroscopy. Singlet CH2 is produced in a hot initial distribution of translation and rotational energy states in the 308nm photodissociation of ketene in a large excess of argon. Collisions with Ar and ketene cool the translational and rotational degrees of freedom, while depleting the total singlet CH2 population through reaction and intersystem crossing. Direct monitoring of the time-dependent populations of rotational levels containing mixed singlet and triplet character reveals a rapid interconversion between the two components, but no discernable difference between the kinetics of the pure singlet and mixed states at longer times.
Patterns of nucleotide misincorporations during enzymatic amplification and direct large-scale sequencing of ancient DNA
Authors: Stiller M. , Green R. E. , Ronan M. , Simons J. F. , Du L. , He W. , Egholm M. , Rothberg J. M. , Keates S. G. , Ovodov N. D. , Antipina E. E. , Baryshnikov G. F. , Kuzmin Y. V. , Vasilevski A. A. , Wuenschell G. E. , Termini J. , Hofreiter M. , Jaenicke-Després V. , Pääbo S.
Published: August 2006

Whereas evolutionary inferences derived from present-day DNA sequences are by necessity indirect, ancient DNA sequences provide a direct view of past genetic variants. However, base lesions that accumulate in DNA over time may cause nucleotide misincorporations when ancient DNA sequences are replicated. By repeated amplifications of mitochondrial DNA sequences from a large number of ancient wolf remains, we show that C/G-to-T/A transitions are the predominant type of such misincorporations. Using a massively parallel sequencing method that allows large numbers of single DNA strands to be sequenced, we show that modifications of C, as well as to a lesser extent of G, residues cause such misincorporations. Experiments where oligonucleotides containing modified bases are used as templates in amplification reactions suggest that both of these types of misincorporations can be caused by deamination of the template bases. New DNA sequencing methods in conjunction with knowledge of misincorporation processes have now, in principle, opened the way for the determination of complete genomes from organisms that became extinct during and after the last glaciation.
The Nck-interacting kinase phosphorylates ERM proteins for formation of lamellipodium by growth factors
Authors: Baumgartner Martin , Sillman Amy L. , Blackwood Elizabeth M. , Srivastava Jyoti , Madson Nikki , Schilling James W. , Wright Jocelyn H. , Barber Diane L.
Published: August 2006

The mammalian Ste20-like Nck-interacting kinase (NIK) and its orthologs Misshapen in
Drosophila
and Mig-15 in
Caenorhabditis elegans
have a conserved function in regulating cell morphology, although through poorly understood mechanisms. We report two previously unrecognized actions of NIK: regulation of lamellipodium formation by growth factors and phosphorylation of the ERM proteins ezrin, radixin, and moesin. ERM proteins regulate cell morphology and plasma membrane dynamics by reversibly anchoring actin filaments to integral plasma membrane proteins.
In vitro
assays show that NIK interacts directly with ERM proteins, binding their N termini and phosphorylating a conserved C-terminal threonine. In cells, NIK and phosphorylated ERM proteins localize at the distal margins of lamellipodia, and NIK activity is necessary for phosphorylation of ERM proteins induced by EGF and PDGF, but not by thrombin. Lamellipodium extension in response to growth factors is inhibited in cells expressing a kinase-inactive NIK, suppressed for NIK expression with siRNA oligonucleotides, or expressing ezrin T567A that cannot be phosphorylated. These data suggest that direct phosphorylation of ERM proteins by NIK constitutes a signaling mechanism controlling growth factor-induced membrane protrusion and cell morphology.
ArrayFusion: a web application for multi-dimensional analysis of CGH, SNP and microarray data
Authors: Yang Tsun-Po , Chang Ting-Yu , Lin Chi-Hung , Hsu Ming-Ta , Wang Hsei-Wei
Published: August 2006

Summary: ArrayFusion annotates conventional CGH results and various types of microarray data from a range of platforms (cDNA, expression, exon, SNP, array-CGH and ChIP-on-chip) and converts them into standard formats which can be visualized in genome browsers (Affymetrix™ Integrated Genome Browser and GBrowse in the HapMap Project). Converted files can then be imported simultaneously into a single genome browser to benefit a collective interpretation between different array results. ArrayFusion therefore provides a new type of tool facilitating the integration of CGH and array results to provide new experimental directions.

Availability:  

Contact:  hwwang@ym.edu.tw
Weighted quality estimates in machine learning
Authors: Budagyan Levon , Abagyan Ruben
Published: August 2006

Motivation: Machine learning methods such as neural networks, support vector machines, and other classification and regression methods rely on iterative optimization of the model quality in the space of the parameters of the method. Model quality measures (accuracies, correlations, etc.) are frequently overly optimistic because the training sets are dominated by particular families and subfamilies. To overcome the bias, the dataset is usually reduced by filtering out closely related objects. However, such filtering uses fixed similarity thresholds and ignores a part of the training information.

Results: We suggested a novel approach to calculate prediction model quality based on assigning to each data point inverse density weights derived from the postulated distance metric. We demonstrated that our new weighted measures estimate the model generalization better and are consistent with the machine learning theory. The Vapnik–Chervonenkis theorem was reformulated and applied to derive the space-uniform error estimates. Two examples were used to illustrate the advantages of the inverse density weighting. First, we demonstrated on a set with a built-in bias that the unweighted cross-validation procedure leads to an overly optimistic quality estimate, while the density-weighted quality estimates are more realistic. Second, an analytical equation for weighted quality estimates was used to derive an SVM model for signal peptide prediction using a full set of known signal peptides, instead of the usual filtered subset.

Contact:  levon@molsoft.com
Species Preferentiality of the Pollen Tube Attractant Derived from the Synergid Cell ofTorenia fournieri
Authors: Higashiyama Tetsuya , Inatsugi Rie , Sakamoto Sachio , Sasaki Narie , Mori Toshiyuki , Kuroiwa Haruko , Nakada Takashi , Nozaki Hisayoshi , Kuroiwa Tsuneyoshi , Nakano Akihiko
Published: August 2006

The synergid cell of Torenia fournieri attracts pollen tubes by a diffusible but yet unknown chemical attractant. Here we investigated the species difference of the attractant using five closely related species in two genera, namely T. fournieri, Torenia baillonii, Torenia concolor, Lindernia (Vandellia) crustacea, and Lindernia micrantha. These five species have an exserted embryo sac, and ablation experiments confirmed that their synergid cells attracted the pollen tube. When ovules of T. fournieri and one of the other species were cultivated together with pollen tubes of each species, pollen tubes were significantly more attracted to synergid cells of the corresponding species. The attraction was not affected by the close proximity of embryo sacs of different species. This suggests that the attractant is a species-preferential molecule that is likely synthesized in the synergid cell. The calcium ion, long considered a potential attractant, could not serve as the sole attractant in these species, because elevation of the calcium ion concentration did not affect the observed attraction. In vivo crossing experiments also showed that the attraction of the pollen tube to the embryo sac was impaired when pollen tubes of different species arrived around the embryo sac, suggesting that the species preferentiality of the attractant may serve as a reproductive barrier in the final step of directional control of the pollen tube.
Discovery of Cyclotide-Like Protein Sequences in Graminaceous Crop Plants: Ancestral Precursors of Circular Proteins?
Authors: Mulvenna Jason P. , Mylne Joshua S. , Bharathi Rekha , Burton Rachel A. , Shirley Neil J. , Fincher Geoffrey B. , Anderson Marilyn A. , Craik David J.
Published: August 2006

Cyclotides are peptides from plants of the Rubiaceae and Violaceae families that have the unusual characteristic of a macrocylic backbone. They are further characterized by their incorporation of a cystine knot in which two disulfides, along with the intervening backbone residues, form a ring through which a third disulfide is threaded. The cyclotides have been found in every Violaceae species screened to date but are apparently present in only a few Rubiaceae species. The selective distribution reported so far raises questions about the evolution of the cyclotides within the plant kingdom. In this study, we use a combined bioinformatics and expression analysis approach to elucidate the evolution and distribution of the cyclotides in the plant kingdom and report the discovery of related sequences widespread in the Poaceae family, including crop plants such as rice (Oryza sativa), maize (Zea mays), and wheat (Triticum aestivum), which carry considerable economic and social importance. The presence of cyclotide-like sequences within these plants suggests that the cyclotides may be derived from an ancestral gene of great antiquity. Quantitative RT-PCR was used to show that two of the discovered cyclotide-like genes from rice and barley (Hordeum vulgare) have tissue-specific expression patterns.
Compounds Responsible for the Color of Black “Ripe” Olives
Authors: SIMPSON KENNETH L. , CHICHESTER C. O. , VAUGHN REESE H.
Published: August 2006

Isolation and purification is reported of a polyphenol that contributes to the color formation in the processed dark olive, known in commerce as the California ripe olive. This compound (probably oleuropein as described by Cruess) was purified by counter‐current distribution. Acid hydrolysis yielded glucose and a second unreported sugar, arabinose. Additional evidence indicates that the compound is not a double ester of glucose, as previously reported.
Volatile Amines in the Odors of Food
Authors: WEURMAN C. , DE ROOIJ CORRY
Published: August 2006

To establish whether using steam distillation in the determination of volatile amines in food might lead to artifact formation, a number of nonvolatile nitrogenous substances known to occur in food were tested under these conditions. The results showed that such a formation need be considered only when relatively large amounts of phosphatides, caffeine, theobromine, or hordenine are present in the sample. A method was worked out to eliminate the artificial production of amines from phosphatides. Selected food items were tested for volatile amines following the suggested procedure, and most of the amines were tentatively identified by paper chromatography. In addition to amines, pyrrolidine was probably found in milk and cocoa powder.
Studies on Frozen Fish. I. Denaturation of Proteins
Authors: SAWANT P. L. , MAGAR N. G.
Published: August 2006

The effect of frozen storage and different glazes on the denaturation of fish proteins was studied. The solubility of proteins was affected less when glazes were used. The denaturation of proteins was restricted to the actomyosin fraction of proteins; the sarcoplasmic fraction remained unchanged. The total actomyosin denaturation was not closely related with either the decrease in apyrase activity of the muscle brei or with the contractility of the muscle fiber.
Comparative Studies on Media for Counting Anaerobic Bacterial Spores. II.
Authors: WHEATON E. , PRATT G. B.
Published: August 2006

Subculture counts using 16 different media representing three general types (fresh‐meat infusion, formulated media, and dehydrated) were compared for the recovery of severely heated spores of two strains of PA3679. Comparative tests with these same media were made on the recovery of heated spores of PA3679, which had been produced in four sporogenic media. In general, the subculture media prepared from fresh‐meat infusions showed the highest recovery counts for all spore suspensions in all experiments. Dehydrated media showed the poorest recovery. The intermediate counts with the formulated media overlapped the counts with the other two groups of media. Pork‐pea infusion extract and beef infusion extract consistently yielded the highest counts and were appreciably higher than any of the dehydrated media. Differences were noted between the response of the two strains of PA3679 to the various subculture media. In addition, differences were noted between the responses to various subculture media on a single strain when the spores were grown on different substrates. Spores of a single strain of PA3679 grown in different substrates showed marked differences in heat resistance.
The Anthocyanins of the American Cranberrya
Authors: SAKAMURA S. , FRANCIS F. J.
Published: August 2006

The red pigments from Early Black cranberries were extracted, separated, and purified. Four distinct bands appeared on silicic acid column. The slowest‐moving band was identified as cyanidin 3‐monogalactoside, the next was peonidin 3‐monogalactoside. The third and fourth were respectively glycosides of cyanidin and peonidin. The absorption coefficients of the purified pigments and the aglucone portions were determined in 95% ethanol–0.1N hydrochloric acid (85:15 v/v).
Studies on Domestic Dates. II. Some Chemical Changes Associated with Deteriorationa,b
Authors: MAIER V. P. , SCHILLER FRANK H.
Published: August 2006

Some chemical changes in Deglet Noor dates during storage at 49° C were studied. Darkening is the combined result of both oxidative and non‐oxidative browning. The former, which constitutes about 10–20% of the total darkening, can be inhibited by storage in inert gas atmospheres. The decrease in pH of the tissue is primarily the result of nonoxidative nonenzymic reactions. Sucrose inversion, the result of invertase action, can be prevented by a mild heat treatment. Oxygen absorption and carbon dioxide production are due to both enzymic and nonenzymic reactions. Apparent phenolase activity increased during storage, whereas apparent peroxidase activity decreased.
Spectral Examination of Cured‐Meat Pigments During Frankfurter Processinga
Authors: SIDWELL C. G. , SALWIN HAROLD , DRIVER MARGARET , KOCH ROBERT B.
Published: August 2006

Spectrophotometric analyses of aqueous‐acetone extracts of frankfurters were useful for characterizing the porphyrin pigments that formed during smokehouse treatment or laboratory heating. The absorption curves showed differences among samples in spectral structure, rates of pigment development, and pigment stability. They also showed promise of differentiating among samples on the basis of storage ‐stability.
The Concentration of Myoglobin and Hemoglobin in Tuna Flesh
Authors: BROWN W. DUANE
Published: August 2006

Amounts of myoglobin and hemoglobin were determined in light and dark muscle of yellowfin tuna, Neothunnus macropterus. Myoglobin concentration ranged from 0.37 to 1.28 mg/g wet weight in light muscle and from 5.3 to 24.4 mg/g in dark muscle; hemoglobin concentrations ranged from 0.12 to 0.58 mg/g in light muscle and from 0.5 to 3.8 mg/g in dark muscle. The fish were divided into two groups on the basis of means of capture, i.e., taken on hooks from a bait boat, or seined. Average percentage of hemoglobin was slightly, but not significantly, higher in the seined fish. Of the total heme pigments, myoglobin constituted 69–85% in light muscle and 81–95% in dark muscle from bait‐boat fish, and 47–81% in light muscle and 84–98% in dark muscle of seined fish.
A Simplified Method for Determination of Some Aspects of the Carotenoid Distribution in Natural and Carotene‐Fortified Orange Juice
Authors: HIGBY WILLIAM K.
Published: August 2006

The unique and complex mixtures of earotenoids in oranges present difficulties in analysis and interpretation of results. The situation is at times further complicated by the addition of β‐carotene to orange juice. Existing analytical procedures, in combination, have been adapted to a rapid quantitative method for both total carotenoids and carotenes. The method involves extraction with a foaming solvent mixture, saponification of esterified oxygenated carotenoids, separation of carotenes by column chromatography, and measurement with a spectrophotometer. An increase in carotenes from the normal level of less than 10% of the total carotenoids to approximately 20% is readily detected, reflecting a sensitivity adequate to the interpretive needs in examining commercial products.
The Effect of Tylosin on Coagulase‐Positive Staphylococci in Food Products
Authors: GREENBERG RICHARD A. , SILLIKER JOHN H.
Published: August 2006

The ability of Tylosin to prevent the growth of coagulase‐positive staphylococci was examined in four food substrates. Staphylococcal development was prevented during the organoleptically acceptable shelf life of ice cream mix by 20 ppm of the antibiotic. Staphylococci were controlled in processed cheddar cheese spread, ham, and domestic sausage by 2.5, 3.0, and 5 ppm Tylosin, respectively. The possible use of Tylosin as a preventive of staphylococcal food poisoning in foods is discussed.
The Action of Tylosin on Spore‐Forming Bacteria
Authors: GREENBERG RICHARD A. , SILLIKER JOHN H.
Published: August 2006

Tylosin at levels up to 100 ppm did not inhibit the germination of spores of Bacillus cereus and Clostridium species PA 3679 in brain heart infusion broth. Death of B. cereus in the presenee of Tylosin was correlated ehronologically with the start of exponential growth in Tylosin‐free control cultures. With PA 3679, the stage most susceptible to Tylosin occurred after germination but prior to exponential growth.
Effects of Tetracycline Antibiotics on the Products of Anserinase Action in Chill Stored Haddock (Gadus aeglefinus) Muscle
Authors: PEREZ B. SANZ , JONES N. R.
Published: August 2006

Anserine (β‐alanyl‐L‐1‐methylhistidine) is cleaved hydrolytically by a haddock muscle enzyme. The inclusion of chlortetracycline and oxytetracycline in ice preserving eviscerated haddock increases the free β‐alanine and L‐l‐methylhistidine recoverable from the muscle during chill storage. This results from their lower utilization by the microfloras selected by tetracyclines. Technological implications are discussed briefly.
Radiation Resistance of Spores of Type E Clostridium As Related to Extension of the Refrigerated Storage Life of Foodsa,b
Authors: SCHMIDT C. F. , LECHOWICH R. V. , NANK W. K.
Published: August 2006

Spores of three strains of Clostridium botulinum Type E were inoculated into 202 × 202 cans of beef stew and irradiated to permit the survival of a small number (50–250) of spores per container. The cans containing survivors were incubated at 43 and 49°F to determine whether germination and outgrowth of surviving spores could take place. With all three strains at least some of the survivors were capable of developing to the point of producing swell spoilage and toxin at both temperatures. The significance. of these results in relation to extension of the refrigerated storage’ life of food by radiation “pasteurization” is discussed.
Some Characteristics of a Proteolytic Enzyme System of Pseudomonas fluorescensa
Authors: HURLEY W. C. , GARDNER F. A. , VANDERZANT CARL
Published: August 2006

When grown in nutrient broth, Pseudomonas fluorescens produced a heat‐labile proteolytic enzyme system that was active against blended fresh egg white, spray‐dried egg white, and hemoglobin. The proteolytie enzyme system was released into the growth medium when the viable cell population had reached a maximum. The proteolytic activity was greater at the higher (25°C) than at the lower temperatures (15, 5°C) of culture incubation. Some purification was obtained by fractionation with ammonium sulfate and cellulose‐column chromatography. The addition of Fe++ to the enzyme preparation greatly increased its activity.
Peonidin‐3‐monoglucoside in Vinifera Grapes
Authors: ALBACH R. F. , KEPNER R. E. , WEBB A. D.
Published: August 2006

The band‐four pigment in the general eight‐band pattern for red vinifera grapes as observed in this laboratory was isolated from Freisa grapes with paper chromatographic techniques. Hydrolysis, partial hydrolysis, and alkaline microdegradation studies on the pure pigment demonstrated that it was peonidin‐3‐monoglucoside.
The Extraction of Pectins from Apple Marc Preparations
Authors: JOSLYN M. A. , DEUEL H.
Published: August 2006

Methods of preparing alcohol‐insoluble solids from apple tissue and different extractives were compared. Marked differences were found in extractability of peetins present in marts prepared in various ways from the same lot of apples. Enzymatic browning during preparation markedly decreased the solubility of pectins but did not alter the composition of pectins extracted. The solubility of pectins present in fresh or dried commercial apple pomace was markedly lower than that from carefully prepared non‐oxidized apple tissue. Pretreatment of browned mart preparations with chlorous acid bleached the mares, yielded colorless pectins, and increased yields with some preparations. A variety of solvents were used, and the yield of pectins obtained differed markedly. The pectins extracted were precipitated by alcohol and characterized by determination of anhydrogalacturonide content and esterification degree. Some measurements of intrinsic viscosity were made, but without extensive studies of the molecular weight and degree of polymerization.
Color Studies on Processed Dried Fruitsa
Authors: NURY F. S. , BREKKE J. E.
Published: August 2006

A procedure for color measurement that can be used in quality determination of dried fruits is described and evaluated for accuracy and reproducibility. Rates of darkening, based on this analytical procedure, are shown for raisins and golden raisins at 50, 70, and 90°F. The apparent activation energies for the browning reaction in these fruits are calculated.
Microbiological Studies of Bruised Tissuesa,b,c
Authors: McCARTHY PATRICIA A. , BROWN WILLIAM , HAMDY MOSTAFA K.
Published: August 2006

Microbiological examination of poultry bruises revealed that 61.0–74.2% of the tissues examined harbored both aerobic and anerobic bacteria. These organisms were found, in experimentally inflicted bruises, to increase in number at the early stages of healing (1–2 days), followed by a rapid decrease to the level of the controls within 4–6 days. Age of bruise, environmental conditions (sanitation of batteries, temperature, and moisture), severity of the bruise, and hemoglobin and its degradation'products were found to be among factors affecting the microbial content and their growth in bruised tissue.

A total of 86 predominant organisms were isolated from experimentally inflicted bruises; of these, 47 were Gram‐positive cocci, 19 Gram‐negative rods, 11 yeasts, 7 Gram‐positive rods, and 2 Gram‐negative cocci. Thirty‐six percent of the Gram‐positive cocci were found to belong to the genus Staphylococcus. Forty‐eight percent of the Staphylococcus cultures were identified as S. aureus, and the others were S. epidermis. Fecal material and poultry feed were shown to be the source of the predominant organisms.

The skin of the injured tissue may be a possible portal of entry of these microorganisms. Bruising increased the permeability of the tissue as determined by dye penetration and the extent of microbial invasion.
Growth of Psychrophiles. II. Growth of Poultry Meat Spoilage Bacteria and Some Effects of Chlortetracyclinea
Authors: WELLS FRANK E. , STADELMAN WILLIAM J. , HARTSELL STANLEY E.
Published: August 2006

The alteration of growth characteristics by environmental factors, such as growth‐temperature reductions and addition of chlortetraeycline to growth medium, was studied. Three bacteria that possessed different psychrophilic abilities were used as test organisms. The stresses imposed were measured by changes in growth rate, cell pigmentation, and lytic response to lysozyme. All strains grew well at 25°C, but differences began to become more pronounced at 12°C and differences were great at 4°C. Temperature fluctuations influenced subsequent growth. The effect of environmental changes on pigmentation varied with the test strain. The lytic response to lysozyme varied but was not greatly influenced by the environmental factors tested. A strain of Brevibacterium linens was found extremely resistant to lysozyme in a number of test systems.
Fish Hydrolysates. III. Influence of degree of hydrolysis on nutritive value
Authors: SRIPATHY N. V. , KADKOL S. B. , SEN D. P. , SWAMINATHAN M. , LAHIRY N. L.
Published: August 2006

Three vacuum‐dried papaic hydrolysates (A and B, short‐term hydrolysis; and C, long‐term hydrolysis) of fish muscle were prepared from a fresh‐water fish, Barbus dubious. They had, in order, α‐amino N contents of 22.5, 28.2, and 42.5%, and sub‐peptone N content of 29.3, 32.6, and 60.9% of total N. The lysine and methionine contents of the three hydrolysates were nearly the same, ranging from 8.88 to 10.53 and 3.11 to 3.50 g/16 g N, respectively, while the tryptophan contents of hydrolysates A and B (0.66 and 0.69 g/16 g N) were much less than that of hydrolysate C (1.16 g/16 g N), indicating slower release of tryptophan than of lysine and methionine during hydrolysis. The protein efficiency ratios of hydrolysates A, B, and C were 2.01, 1.87, and 2.88 at 5% level, and 2.31, 2.39, and 2.95 at 10% level of protein intake, compared with 2.92 and 3.19 for the proteins of skim‐milk powder. Weight gain response by the rat repletion method, using adult rats, showed a similar trend for the nutritive value of the hydrolysates. The superior nutritive value of hydrolysate C may be due to its higher tryptophan content.
Correlation of Gas Chromatographic Data with Flavor Profiles of Fresh Banana Fruita
Authors: McCARTHY ALICE I. , PALMER JAMES K. , SHAW CAROL P. , ANDERSON EDWARD E.
Published: August 2006

Data obtained with several banana varieties show excellent qualitative and quantitative correlations between the development of flavor and odor notes and chemical analysis for volatiles by gas‐liquid chromatography. The characteristic “banana‐like” flavor is due to the amyl esters of acetic, propionic, and butyric acids. The distinctive “fruity” and “estery” notes are attributed to butyl acetate, butyl butyrate, hexyl acetate, and amyl butyrate. It is evident from these studies that determination of the chemical composition of the volatiles has permitted a much more precise characterization of flavor and odor notes, and, conversely, that these flavor profiles contribute greatly to interpretation of the significance of chemical constituents. The correlations found also substantiate the potential value of gas chromatographic analysis for routine evaluation of banana fruit quality. It is anticipated that the combined use of these two techniques will enhance the value of both in their application to numerous flavor and odor problems.
Development of Standard Rating Scales for Mechanical Parameters of Texture and Correlation Between the Objective and the Sensory Methods of Texture Evaluation
Authors: SZCZESNIAK ALINA SURMACKA , BRANDT MARGARET A. , FRIEDMAN HERMAN H.
Published: August 2006

Standard rating scales of hardness, brittleness, chewiness, gumminess, viscosity, and adhesiveness were established for quantitative evaluation of food texture. The scales cover the entire intensity range found in food products and may be expanded at any desired point for greater precision in a narrower range. Each point on the scale is represented by a food product selected on the basis of availability, familiarity, constancy of textural characteristics, and other criteria. Using the developed scales, correlation was good between sensory and instrumental (texturometer and viscosimeter) evaluations of texture.
Spectrometry in Organic Analysis. Application to Small Samples
Authors: BASSLER G. C. , SILVERSTEIN R. M.
Published: August 2006

Gas chromatography offers the food chemist an unparalleled technique for separation and isolation of the components of complex volatile mixtures. Unfortunately, the problem of compound identification still remains. Often, the available quantity of an isolated pure compound may not exceed one or two milligrams. Conventional organic analytical techniques are seldom adequate for identification of such small samples. An empirical examination of infrared, ultraviolet, mass, and nuclear magnetic resonance (NMR) spectra permits the solution of a gratifying number of identification problems.

The application of mass spectrometry to the identification of organic compounds is discussed briefly. Two sets of spectra are translated into organic structures as examples of the methodology.
Alteration of the Flavor of Processed Vegetables by Enzyme Preparations
Authors: SCHWIMMER SIGMUND
Published: August 2006

The role of enzymes as agents for the restoration of fresh food flavor in processed foods is embodied in the “flavorese” concept of Hewitt et al. (1956). The experimental validity of this concept has been tested by adding a vegetable enzyme fraction to food prepared from the same or phylogenetically related vegetable. The flavor of the enzyme‐treated processed food approached that of the fresh vegetable hut was not identical with it. In general, addition of enzyme tended to over‐emphasize certain notes of the natural flavor. Odor changes were more readily detected than changes in taste. Both the qualitative and quantitative aspects of the flavor changes were affected by the processing of the vegetables, by the method and source of enzyme preparation, and by the conditions under which the alterations in flavor occurred. These results are discussed in light of the enzymology underlying the flavor changes.
Effect of Excitement, Fasting, and Sucrose Feeding on Porcine Muscle Phosphorylase and Post‐Mortem Glycolysisa,b
Authors: SAYRE R. N. , BRISKEY E. J. , HOEKSTRA W. G.
Published: August 2006

Phosphorylase activities were studied in relation to pre‐slaughter treatment, post‐mortem glycolysis, and ultimate characteristics of porcine longissimus dorsi. Total phosphorylase activity was not affected by pre‐slaughter treatment and did not appear to be associated with post‐mortem muscle glycolytic rate or ultimate muscle characteristics. The Hampshire muscles which had high muscle glycogen levels immediately post‐mortem also possessed especially high levels of total phosphorylase; however, when all breeds were considered, the within breed correlations for these two factors were not significant (p 0.05). Insufficient knowledge exists on the relation of the time course of phosphorylase activation and glycolytic rate in post‐mortem muscle. Nevertheless, extracts of porcine muscle at 10 min post‐mortem generally showed the phosphorylase to be in the b form.

Short‐term excitement and exercise immediately prior to slaughter caused a rapid post‐mortem glycolysis, indicated by a rapid pH decline and decrease of color intensity in the muscle. This rapid glycolysis resulted in muscle with inferior water‐binding properties and low color and texture scores. Long‐ and short‐term sucrose feeding elevated the glycogen level of the muscle at slaughter, which ultimately resulted in muscle that was slightly soft and pale. Fasting 70 hr prior to slaughter lowered the initial glycogen content of the muscle and also slowed pH decline and color change during post‐mortem glycolysis. Correlation between pH values and the ultimate color and water‐binding properties of the muscle were significant soon after death, declining thereafter.
Lipid Alterations During the Fermentation of Vegetables by the Lactic Acid Bacteriaa
Authors: VOKBECK M. L. , ALBURY M. N. , MATTICK L. R. , LEE F. A. , PEDERSON C. S.
Published: August 2006

Qualitative and quantitative analyses of the fatty acids of the various lipid fractions of raw and fermented cabbage and Brussels sprouts were made by gas‐liquid chromatography of the methyl esters.

The amount of free or non‐esterified fatty acids increased considerably in the lipid fractions of both vegetables as a result of fermentation. The unsaponifiable matter, and the fatty acids of both the acetone‐soluble and acetone‐insoluble fractions of the vegetables, decreased during the fermentations.

Free or non‐esterified palmitic acid increased significantly during fermentation—from 0.63 to 6.87% of the total fatty acid lipid in the cabbage fermentation. Results were similar in Brussels sprouts. During fermentation, the unsaturated C18 fatty acids decreased while the shorter‐chain fatty acids increased. As a result of fermentation, a change was observed in the waxy or shiny appearance of the cabbage. The presence of longer‐chain saturated fatty acids in the non‐esterified fatty acid fraction of the fermented material has been attributed to the changes in the unsaponifiable fraction. These longer‐chain fatty acids were notably absent from the fatty acids of the acetone‐soluble and acetone‐insoluble lipids of the unfermented vegetables.

The data suggest that the changes in the lipid fraction during fermentation were effected primarily through the metabolic activities of the various lactic acid bacteria. Since it is known that many of the lactic acid bacteria require certain fatty acids for growth, it has been postulated that the changes in the lipid fraction could influence the growth and sequence of the various bacterial types that are observed in a particular fermentation.
The Relationship of Some Intracellular Protein Characteristics to Beef Muscle Tenderness a,b
Authors: HEGARTY G. R. , BRATZLER L. J. , PEARSON A. M.
Published: August 2006

A procedure developed to fractionate the major nitrogen‐containing components of muscle was utilized to study the relationship of intracellular muscle proteins to tenderness. The study was performed on a group of 20 yearling bulls from two lines of cattle that had been selected for differences in tenderness. The longissimus dorsi muscle contained more total nitrogen per unit of muscle tissue and almost twice as much sarcoplasmic protein as the infra‐spinatus muscle. The longissimus dorsi contained less fibrillar protein and non‐protein nitrogen than the infraspinatus. The following factors were correlated with tenderness as measured by shear and panel: sarcoplasmic protein nitrogen/total fibrillar protein nitrogen; soluble fibrillar protein nitrogen/ total fibrillar protein nitrogen; water released/total water. Fibrillar protein solubility was highly correlated with tenderness (r.=−0.69 for shear and r= 0.59 for panel). An r value of 0.49, significant at the 5% level, was found between water‐holding capacity and tenderness as measured by the shear.