bluuebunny/crossref_metadata_2025 huggingface dataset:
CHARACTERIZATION OF THE MICROFLORA ISOLATED FROM QUESO FRESCO MADE FROM RAW AND PASTEURIZED MILK*
Authors: RENYE J.A. , SOMKUTI G.A. , VALLEJO‐CORDOBA B. , VAN HEKKEN D.L. , GONZALEZ‐CORDOVA A.F.
Published: February 2008

This study characterized the microflora present in four Queso Fresco‐style cheeses made from raw milk (RM) and two cheeses made from pasteurized milk (PM) obtained directly from six different producers in Mexico. Microbial isolates were initially analyzed on 8 different selective media and further analyzed by 16S rRNA gene sequence analysis. Sequence analysis identified Lactococcus lactis ssp. lactis as an isolate growing on M17 agar in four cheese samples. L. lactis ssp. lactis was the only lactic acid bacterium identified which is traditionally used as a cheese starter culture. Sequence analysis of isolates from MRS medium supplemented with vancomycin identified Leuconostoc mesenteroides in all six cheese samples. A high number of coliforms, enterococci and coagulase‐positive staphylococci were identified in all RM cheeses. The numbers of total coliform species were lower in both PM samples (by 2 log10), but the numbers of staphylococci were lower in only one sample (by 3 log10). The numbers of enterococci were high in both PM samples, and sequence analysis identified Enterococcus faecium as the only enterococcal species isolated from all six cheeses. These results suggest that L. lactis ssp. lactis, L. mesenteroides and E. faecium are species that may contribute to the organoleptic qualities of Queso Fresco‐style cheeses analyzed in this study.

PRACTICAL APPLICATIONS

This work was performed to define the natural microflora present in traditional‐style Queso Fresco in order to identify bacterial species that may contribute to the organoleptic qualities of the cheese. Identification and enumeration of the “generally regarded as safe” (GRAS) lactic acid bacteria may allow for the development of new culture blends for the production of Queso Fresco using pasteurized milk, while maintaining the desired qualities of the raw milk varieties. In addition, bacteria recovered from the raw milk cheeses may be novel strains offering advantages over commercially available starter and adjunct LAB currently being used to make Queso Fresco. The work also identified potential pathogens and spoilage bacteria associated with traditional‐style Queso Fresco, stressing the importance in developing a desirable pasteurized milk cheese.
EFFECTS OF DIFFERENT STORAGE CONDITIONS ON AFLATOXIN FORMATION IN KÖME INOCULATED WITH ASPERGILLUS PARASITICUS NRRL 2999
Authors: YILDIZ HİLAL , SERT SELAHATTİN , GÜRSES MUSTAFA
Published: February 2008

In this study, Köme with walnuts were investigated for aflatoxin production. One part of stringed walnuts was inoculated at 104 spores/g with the Aspergillus parasiticus NRRL 2999 strain, and the other as control group was not inoculated. The Köme samples were stored at 20 ± 1C at 85 ± 2% and 95 ± 2% relative humidity for 45 days. All the samples were subjected to aflatoxin B1 (AFB1) and total aflatoxin analysis in certain time intervals (1, 4, 7, 15, 30 and 45 days). Enzyme‐linked immunosorbent assay was used to detect the amounts of aflatoxins. At 85 ± 2% and 95 ± 2% relative humidity, the detected amounts of aflatoxins were 616.15 ng/kg AFB1 and 1747.16 ng/kg aflatoxin total, and 732.98 ng/kg AFB1 and 2039.02 ng/kg total at the end of 45 days, respectively. The findings of this research indicated that aflatoxin formation in Köme is dependent on the storage conditions, such as mold contamination, and relative humidity. Aflatoxin production was found in high levels at the 95 ± 2% relative humidity.

PRACTICAL APPLICATIONS

This study contributes to a better understanding of the effect on aflatoxin production of factors such as relative humidity and mold contamination. This approach is useful for determining storage conditions that would prevent aflatoxin formation.
OCCURRENCE OF CAMPYLOBACTER SPECIES, SALMONELLA SPECIES AND GENERIC ESCHERICHIA COLI IN MEAT PRODUCTS FROM RETAIL OUTLETS IN THE FARGO METROPOLITAN AREA
Authors: KEGODE REDEMPTA B. , DOETKOTT DAWN K. , KHAITSA MARGARET L. , WESLEY IRENE V.
Published: February 2008

Foodborne illnesses are a substantial health burden in the United States, with Campylobacter, pathogenic Escherichia coli and Salmonella reported among the major bacterial foodborne pathogens. These organisms are often present in fresh meat and poultry with regional differences in incidence. The objectives of this study were (1) to determine occurrence of foodborne pathogens Campylobacter and Salmonella as well as generic Escherichia coli in raw meats sold in retail grocery stores in the Fargo metropolitan area of North Dakota in the Midwestern United States; and (2) to correlate observed prevalence with the product type and retail store. A total of 456 fresh raw meats (turkey, chicken, pork, beef) were purchased and tested for microbial contamination. Overall, 341 (75%) of the samples were contaminated with generic E. coli (n = 316, 72%), Campylobacter (n = 12, 2.6%) and Salmonella (n = 13, 2.9%). The meats differed significantly (P < 0.0001) in contamination rate with Campylobacter and Salmonella, but not among the five stores.

PRACTICAL APPLICATIONS

The data indicate that meat products, particularly poultry (chicken and turkey), purchased from retail stores in the Fargo metropolitan area may occasionally be contaminated with Campylobacter and Salmonella. This signifies the importance of sustained surveillance of foodborne pathogens in retail meats. In addition, the data suggest that microbial contamination on raw retail meats purchased in the metropolitan area of a rural agricultural state are not higher than those reported for larger urban locales.
PULSED ELECTRIC FIELD PROCESSING OF FORMULATED RICE PUDDING
Authors: RATANATRIWONG P. , EVRENDILEK G. AKDEMIR , ZHANG Q.H.
Published: February 2008

The objectives of the study were to formulate a rice pudding to be processed by pulsed electric fields (PEF), define suitable PEF parameters and measure the shelf life of PEF‐treated rice pudding. Rice pudding was processed by a combination of mild heat (55C for 30 s) and PEF. PEF processing parameters were 33 kV/cm electric field strength, 100 L/h flow rate, 1.47 µs pulse duration and 500 pps repetition rate. The samples were then aseptically packed and kept at 4C for 94 days. pH, color, total aerobic plate count (TPC) and total mold and yeast count (TMY) were measured during shelf life study. pH, TPC and TMY counts showed the effectiveness of PEF system in that 55C+PEF‐treated products had significantly longer shelf life than that of control group (P < 0.05). L, a, and b values for color measurement of the control and the 55C+PEF‐treated samples were not significantly different (P > 0.05).

PRACTICAL APPLICATIONS

The extension of pulsed electric field (PEF) technology to high‐viscosity low‐acidity particulate food requires better understanding of product characteristics and PEF systems. This study is another approach to present the applicability of PEFs to particulate foods. In order to process rice pudding, a mild heat treatment at 55C for 30 s was combined with PEFs. In this frame, reformulation of rice pudding, determination of PEF processing parameters and shelf life study of PEF‐processed rice pudding was studied. It was demonstrated that 55C+PEF treatment of rice pudding is a viable option for food industry.
COMPARISON OF RESPONSE SURFACE METHODOLOGY AND THE PROPOSED WEIBULL MODEL FOR INACTIVATION OF LISTERIA INNOCUA BY HIGH HYDROSTATIC PRESSURE
Authors: BUZRUL SENCER , ÇEVİK METE , ALPAS HAMİ
Published: February 2008

Published inactivation data of Listeria innocua by high hydrostatic pressure (HHP) were used to compare the prediction capabilities of response surface methodology (RSM) and the proposed Weibull model. A quadratic function was used for the secondary modeling of the reduced Weibull model's time constant parameter so that this model consisted of pressure, temperature and time just like RSM equation. Application of each model was shown separately. The usability, differences and similarities of these models were also pointed out. In general, the reduced Weibull model gave better predictions than RSM at 207 and 276 MPa for three temperature values (25, 35 and 45C); however, at 345 MPa for 35 and 45C just the opposite was observed.

PRACTICAL APPLICATIONS

It becomes increasingly apparent that high hydrostatic pressure treatment of food products is often required for effective microbial inactivation. In consequence the prediction of microbial inactivation is essential. Accurate prediction of high hydrostatic pressure inactivation by means of different modeling approaches would be very beneficial to the food industry in selecting optimum combinations of pressure, temperature and time to obtain desired levels of microbial inactivation while minimizing the production costs and maintaining a maximum degree of sensory and nutrient quality.
RICE‐EATING QUALITY AMONG CONSUMERS IN DIFFERENT RICE GRAIN PREFERENCE COUNTRIES
Authors: SUWANNAPORN PRISANA , LINNEMANN ANITA
Published: February 2008

More rice is eaten nowadays in traditionally nonrice‐eating countries. This study investigated consumer eating quality preferences among consumers in target rice export countries to identify opportunities and strategic implications. A quantitative study with 1,128 consumers of target nationalities was conducted in combination with focus group discussions. Discrimination analysis was performed to investigate differences in perception between consumers from countries which had different rice grain preference. Result showed that rice texture was the best discriminator. It could correctly predict consumers from nonspecific grain preference, short grain preference and Basmati preference at 63, 71 and 81%, respectively. Jasmine rice had its unique quality, which was highly differentiated between people who prefer and do not prefer it (α = 0.00). Jasmine rice aroma was not a decisive quality attribute for consumers in general. However, it was a desirable quality trait for those who specifically prefer Jasmine rice. Consumers from the nonrice‐eating countries preferred harder and less sticky rice that was a threat for Jasmine rice in this region. Thai exporters should offer various grain qualities that suit different taste preferences instead of focusing only on Jasmine rice.

PRACTICAL APPLICATIONS

This study found that rice aroma was not a decisive quality attribute for some consumer especially for those originating from nonrice‐eating countries and some Asians. So, Jasmine rice was not always preferred. Consumers from the rice‐eating countries tended to prefer their country's traditional rice variety, which was not easy to change. However, differentiation strategy via diffusion process through Thai cuisine or Thai restaurant can make Jasmine rice an indispensable niche. Consumers from the nonrice‐eating countries have started to develop a preference for long grain rice but with no specific preference among grain varieties. They obviously prefer harder and less sticky rice as the influence of the market pioneer, the American rice. Instead of focusing only on Jasmine rice, Thai rice exporters should offer various rice grain qualities that suit different taste preferences.
ODOR IDENTIFICATION ABILITY PREDICTS CHANGES IN SYMPTOMS OF PSYCHOPATHOLOGY FOLLOWING 56 H OF SLEEP DEPRIVATION
Authors: KILLGORE WILLIAM D.S. , KILLGORE DESIREE B. , MCBRIDE SHARON A. , KAMIMORI GARY H. , BALKIN THOMAS J.
Published: February 2008

ABSTRACTS

A person's ability to identify odors provides an index of the functional integrity of the brain's prefrontal cortex. Some evidence suggests that the functional activity of the prefrontal cortex, when well rested, may predict individual differences in the ability to sustain performance when subsequently sleep deprived. It was hypothesized that odor identification accuracy, when rested would predict the vulnerability to sleep deprivation‐mediated elevations of affective symptoms of psychopathology, as measured on the Personality Assessment Inventory (PAI). Twenty‐two healthy volunteers completed the University of Pennsylvania Smell Identification Test (SIT) and the PAI when rested. After 56 h of continuous wakefulness, participants were re‐administered the PAI. Poorer odor identification at baseline correlated with increased symptoms of depression and borderline negative relationships. In contrast, higher SIT scores correlated with increased manic irritability. Results suggest that better olfactory identification in the well‐rested state (a putative index of orbitofrontal cortex integrity) predicts affective stability during subsequent sleep deprivation.

PRACTICAL APPLICATIONS

The findings of the study showed that a brief, portable and easily administered test of olfactory perception was effective at identifying individuals that were likely to show degradation of emotional and cognitive performance when sleep deprived. With further validation, odor identification tasks, such as the Smell Identification Test, may provide quick screening tools to aid in identifying and selecting personnel that may operate most effectively under adverse conditions of prolonged wakefulness.
CONSUMER PERCEPTION OF SOY AND DAIRY PRODUCTS: A CROSS‐CULTURAL STUDY
Authors: JONES V.S. , DRAKE M.A. , HARDING R. , KUHN‐SHERLOCK B.
Published: February 2008

Soy and dairy are the two main sources of protein that are used in specialized products such as sports bars and beverages. Historically, New Zealanders have consumed mainly dairy products, whereas American consumers have been exposed to both soy and dairy. The purpose of this research was to collect consumer views and opinions from New Zealand (NZ) and U.S. consumers about the health benefits and product claims associated with soy and dairy products and to determine if there were any cross‐cultural differences. Consumers from the U.S.A. and NZ answered a usage and attitude questionnaire and completed a conjoint analysis survey on their general knowledge and perception of the health benefits of soy and dairy products and the differences between these products. Both groups of consumers associated specific health claims with each protein source. There were minimal differences between U.S. and NZ consumers in their knowledge and perception of soy and dairy products; however, NZ consumers had a greater preference for dairy, whereas U.S. consumers did not differentiate their choice of protein source as clearly.

PRACTICAL APPLICATIONS

The insights gained in this study give researchers and marketers information about how soy and dairy products are perceived by consumers. It provides information about the specific health claims that consumers attribute to soy and dairy and what preferences they have for these products. The similarities and differences that are shown between U.S. and New Zealand consumers are beneficial to know when formulating products to sell in today's global food industry.
TABLES FOR PARITY TESTING
Authors: ENNIS DANIEL M.
Published: February 2008

There is frequent interest in establishing whether two products or treatments are essentially equivalent or at parity. Two types of parity hypotheses are defined in this article, an unsurpassed hypothesis and an equality hypothesis. Tables for these two types of parity hypotheses are presented for 2‐alternative forced choice and preference data. These two hypotheses are often used in product testing for claims support involving either equality or unsurpassed claims. The basis for the tables is presented along with illustrative examples of their use in product testing.

PRACTICAL APPLICATIONS

There are many industrial applications in which it is desirable to know whether one product can act as a substitute for another. Examples include blend and flavor modifications of products that are necessary when ingredients change as a result of natural seasonal variation or of changes in suppliers. Products are often deliberately modified in response to government regulations, availability of raw materials, substitution to more healthful or lower cost components, or are inadvertently modified because a new factory has come online. In addition, some companies develop products that are direct substitutes for their competitors and make advertising claims concerning their equivalency. These applications require a reliable basis for making recommendations concerning product substitutions or parity statements.
EFFECT OF THE GLASS SHAPE ON FLAVOR PERCEPTION OF “TOASTED WINE” FROM RIBEIRO (NW SPAIN)
Authors: VILANOVA MAR , VIDAL PABLO , CORTÉS SANDRA
Published: February 2008

The objective of this study was to determine the effect of geometries of nine glass types on the sensory perception of sweet “toasted wine” from the Appellation of Origin Ribeiro wine. Nine wine tasters conducted the sensory evaluation. The subjects compared six Ribeiro wines with nine different glasses. Visual, nose and taste expression of wines were rated repeatedly before and after drinking in each type of glass. Harmony and functionality were rated as well.

Ratings of wine and glass descriptors from different glasses were influenced by glass shape. The present study indicates that the shape of glasses has an influence on the perception of the characteristics of “toasted wine.”

PRACTICAL APPLICATIONS

The results of our study suggest that the glass shape has an effect on the perception of odor and flavor of “toasted wine.” The results showed that the glass type G was the one recommended by the wine tasters to consume the “toasted wine” from the Appellation of Origin Ribeiro.
COMPARISON OF INSTRUMENTAL METHODS FOR MEASURING SEED HARDNESS OF FOOD‐GRADE SOYBEAN
Authors: ZHANG BO , TAMURA MIOKO , BERGER‐DOYLE JOYCE , CHEN PENGYIN
Published: February 2008

Breeding specialty soybeans for the soyfood market requires proper methodology in evaluation of seed quality attributes. In this study, efficient methods that could be potentially used for testing soybean seed hardness were developed by examining different instruments and seed parameters. Five food‐grade soybean genotypes with different seed sizes were used to determine seed water‐absorption capacity and hardness. Water absorption capacity was expressed by swell ratios for seed weight, seed dimension, and volume of water changes before and after soaking. Seed hardness test was conducted by a one‐bite method using a food texture analyzer equipped with five different probes. The results showed that hardness testing by a 75 mm cylinder with 10 steamed seeds, single blade with five steamed seeds, and shear cell with 30 g steamed seeds produced dependable and consistent results with low coefficient of variance. However, shear cell may not be practical for early plant selection in a breeding program due to a relatively large sample requirement. Seed size can be used as indirect selection indicators for seed hardness.

PRACTICAL APPLICATIONS

Seed hardness is an important factor in determining soybean suitability for natto production. This study used two texture analyzers equipped with five different probes to test hardness of five soybean genotypes with different seed size. The methodologies for testing the seed texture of soybean have been established, which can help regulate the seed hardness testing for commercial production and provide consistent hardness references for natto breeding programs and the seed industry.
EFFECT OF COLD STORAGE ON CULTURE VIABILITY AND SOME RHEOLOGICAL PROPERTIES OF FERMENTED MILK PREPARED WITH YOGURT AND PROBIOTIC BACTERIA
Authors: DAMIN MARIA REGINA , MINOWA EIMY , ALCÂNTARA MARIA REGINA , OLIVEIRA MARICÊ NOGUEIRA
Published: February 2008

We examined the effect of storage time on culture viability and some rheological properties (yield stress, storage modulus, loss modulus, linear viscoelastic region, structural recuperation and firmness) of fermented milk made with Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus (LA) and Bifidobacterium animalis ssp. lactis in coculture with Streptococcus thermophilus (ST). Acidification profiles and factors that affect viability (postfermentation acidification, acidity and dissolved oxygen) were also studied during 35 days at 4C. Fermented milk prepared with a coculture of ST and Bifidobacterium lactis gave the most constant rheological behavior and the best cell viability during cold storage; it was superior to ST plus LA for probiotic fermented milk production.

PRACTICAL APPLICATIONS

Probiotic cultures should grow quickly in milk, provide adequate sensory and rheological properties to the product, and remain viable during storage. Commercially, it is very common to use yogurt starter culture (i.e. Streptococcus thermophilus[ST] and Lactobacillus delbrueckii ssp. bulgaricus) in combination with the probiotic bacteria in order to reduce fermentation time. However, LB tends to post acidify fermented milk, which reduces the viability of the probiotic bacteria; thus, it is recommended to use starter cultures devoid of this species. We found that the technological properties and the viability of the probiotic bacterium Bifidobacterium animalis ssp. lactis BL O4 in coculture with ST make it suitable for probiotic fermented milk production; it produces rheological characteristics similar to those of yogurt.
PRODUCTION AND CHARACTERIZATION OF SPONGE‐DOUGH BREAD USING SCALDED RYE
Authors: ESTELLER MAURICIO S. , LANNES SUZANA C.S.
Published: February 2008

In this work, flatbed scanning, instrumental texture analysis, spectrophotometric color determination (L*, a*, b*), moisture and specific volume measurements were used to evaluate the effects of the addition of rye flour or rye flakes, yeast and boiling water in different amounts in sponge‐dough rye bread production. The treatments changed significantly (P < 0.05) the crumb cell area (mm2), cell diameter (mm), cell perimeter (mm), texture parameters and light reflectance (L*, a*, b*). Scalding process could be used to produce new textures and color of baked products.

PRACTICAL APPLICATIONS

Fermented foods contribute to about one‐third of the diet worldwide. Fermentation causes changes in texture, flavor, appearance, nutrition and safety of food. Many cereal products start with heat treatment to change protein and starch properties, removal of antinutrients, natural toxicants and mycotoxins, before fermentation. The study of microstructure can be used to increase understanding of the changes that occur during processing of food and the role of different ingredients, allowing a better control of the structure and regulation of texture. Designing texturally appealing foods presents a new challenge to companies.
EFFECT OF COOKING TIME AND STORAGE TEMPERATURE ON THE TEXTURAL PROPERTIES OF CASSAVA DOUGH
Authors: RODRÍGUEZ‐SANDOVAL EDUARDO , FERNÁNDEZ‐QUINTERO ALEJANDRO , SANDOVAL‐ALDANA ANGÉLICA , QUICAZÁN MARTHA CECILIA
Published: February 2008

The characteristics of the texture of cassava dough were evaluated using the stress–relaxation test and texture profile analysis. Cassava parenchyma processed under different cooking times, 15 or 18 min, and stored at either −5 or −20C for 24 h was used to produce the dough. Two stress–relaxation models, Maxwell and Peleg, were fitted to the experimental data. Both models were validated for quantifying the relaxation behavior; but the Maxwell model best fitted the experimental data. Dough samples from the parenchyma cooked for 18 min and stored at −20C showed the lowest elastic moduli, viscosities, initial compressive relaxation modulus and hardness values. It was concluded that higher cooking times and lower temperatures during the storage period increased the degree of retrogradation of starch granules, affecting the textural properties of cassava dough.

PRACTICAL APPLICATIONS

There are new and growing industries in cassava‐producing countries that use fresh cassava roots in order to produce high added‐value products like croquettes, fried chips or snacks. Cassava dough is an intermediate product for making cassava croquettes, which is a stick‐fried food well positioned in the Colombian market. The study of the rheologic and textural behavior of cassava dough is important for processing improvements in the cassava croquette industry. The results of this investigation showed that stress–relaxation test and texture profile analysis were sensitive to identify changes related to different processing conditions; in addition, the higher cooking times and lower temperatures during the storage period decreased the stiffness of cassava dough, affecting its handling in a following process.
ORAL PHYSIOLOGY AND TEXTURE PERCEPTION OF SEMISOLIDS
Authors: ENGELEN LINA , VAN DER BILT ANDRIES
Published: February 2008

In the oral cavity, the food is subjected to several mechanical and chemical processes. It is fractured by the teeth, diluted and broken down by saliva, heated or cooled by the ambient temperature of the mouth, formed into a bolus and finally swallowed. Numerous receptors in the oral cavity and nose respond to the initially ingested food and monitor the changes during processing. This leads to central perceptions of taste, odor, irritation and texture of the food. Most sensations associated with food texture occur only when the food is manipulated, deformed or moved across the oral receptors. In addition, people assessing the same stimulus differ in their ratings of that stimulus and their oral physiological parameters also exhibit inter‐individual variations.

This paper is based on the PhD thesis of one of the authors. It gives an overview of this study and includes related work of other authors. The aim of our research was to improve the understanding of oral texture perception, in particular to examine the role of oral physiological processes in oral texture perception of semisolids and to investigate whether individual differences in perception could be attributed to differences in oral physiology among subjects.

The results of our study demonstrate that oral physiological parameters such as oral sensitivity, tongue movements, temperature and saliva composition are of importance for texture perception of semisolids. Many parameters of oral physiology correlate with various perceived texture attributes. This implies that intra‐individual differences in texture perception could be attributed to variations in oral physiology. Oral physiology thus plays a role in texture perception of semisolids and should be taken into account in future texture research.

PRACTICAL APPLICATIONS

By understanding the processes in the mouth while eating, a better understanding of the sensations and the perceptions of the food can be gained. Taking for each food the relevant physiological parameter into consideration when performing and designing rheological/instrumental measurements grants more natural conditions and better predictions of sensory perception. This could save time and money on time‐consuming and expensive sensory panels in the earlier steps of product development and renovation. Knowing how physiological processes highlight specific flavor/texture sensations may be useful for product development or quality control where one typically wants to focus on certain sensations and ignores others. In addition, a future application could be to tailor products for personalized nutrition, individual choices or clinical nutrition based on physiological groups.
HUMAN CAPITAL INEQUALITY AND THE KUZNETS CURVE
Authors: LIM Audrey Siew Kim , TANG Kam Ki
Published: February 2008

This paper develops a Mincerian measure of human capital distribution and applies it to evaluate national and global human capital inequality and compare them with education inequality measures. It is shown that using education inequality as a proxy of human capital inequality is problematic due to the nonmonotonic relationship between them. We find that the inconsistent evidence on education and human capital Kuznets curves in the literature is due to the use of different inequality measures. In particular, human capital Kuznets curves are evident when relative inequality measures are used, whereas education Kuznets curves are found when absolute inequality measures are used. It is also observed that while global education inequality has been declining over the past four decades, global human capital inequality remains largely steady, as the decrease in between‐country human capital inequality is largely balanced by the increase in within‐country human capital inequality.
The Madness of the Mob? Explaining the ‘Irrationality’ and Destructiveness of Crowd Violence
Authors: Waddington David
Published: February 2008

This article responds to a recent suggestion by Borch (2006) that sociologists might profitably reconsider the ‘group mind’ explanation, propagated by nineteenth‐century French academics like Tarde and Le Bon, which emphasises the inherent suggestibility, amorality, and destructiveness of crowds as mechanisms of accounting for collective violence. In alluding to the recent French riots of October–November 2005 as an illustrative example, the article rejects the group mind approach (along with a host of other lay explanations appearing in the wake of the disorders) in favour of a multivariate analysis, loosely based on the Flashpoints Model of Public Disorder. The purpose of this analysis is to demonstrate how even the most intensely destructive, spontaneous and emotional acts of collective violence are typically underpinned by a guiding and restraining rationality.
Developmental changes in calcium/calmodulin‐dependent inactivation of calcium currents at the rat calyx of Held
Authors: Nakamura Takeshi , Yamashita Takayuki , Saitoh Naoto , Takahashi Tomoyuki
Published: February 2008

Ca2+‐binding to calmodulin (CaM) causes facilitation and/or inactivation of recombinant Ca2+ channels. At the rat calyx of Held, before hearing onset, presynaptic Ca2+ currents (IpCa) undergo Ca2+/CaM‐dependent inactivation during repetitive activation at around 1 Hz, implying that this may be a major cause of short‐term synaptic depression. However, it remains open whether the Ca2+/CaM‐dependent inactivation of IpCa persists in more mature animals. To address this question, we tested the effect of CaM inhibitors on the activity‐dependent modulation of IpCa in calyces, before (postnatal day (P) 7–9) and after (P13–15) hearing onset. Our results indicate that the CaM‐dependent IpCa inactivation during low‐frequency stimulation, and the ensuing synaptic depression, occur only at calyces in the prehearing period. However, CaM immunoreactivity in P8 and P14 calyces was equally strong. Even at P13–15, high frequency stimulation (200–500 Hz) could induce IpCa inactivation, which was attenuated by EGTA (10 mm) or a CaM inhibitor peptide loaded into the terminal. Furthermore, the CaM inhibitor peptide attenuated a transient facilitation of IpCa preceding inactivation observed at 500 Hz stimulation, whereas it had no effect on sustained IpCa facilitations during trains of 50–200 Hz stimulation. These results suggest that the Ca2+/CaM‐dependent IpCa modulation requires a high intraterminal Ca2+ concentration, which can be attained at immature calyces during low frequency stimulation, but only during unusually high frequency stimulation at calyceal terminals in the posthearing period.
Network hyperexcitability within the deep layers of the pilocarpine‐treated rat entorhinal cortex
Authors: De Guzman Philip , Inaba Yuji , Baldelli Enrica , De Curtis Marco , Biagini Giuseppe , Avoli Massimo
Published: February 2008

In this study we report that in the presence of normal buffer, epileptiform discharges occur spontaneously (duration = 2.60 ± 0.49 s) or can be induced by electrical stimuli (duration = 2.50 ± 0.62 s) in the entorhinal cortex (EC) of brain slices obtained from pilocarpine‐treated rats but not in those from age‐matched, nonepileptic control (NEC) animals. These network‐driven epileptiform events consist of field oscillatory sequences at frequencies greater than 200 Hz that most often initiate in the lateral EC and propagate to the medial EC with 4–63 ms delays. The NMDA receptor antagonist CPP depresses the rate of occurrence (P < 0.01) of these spontaneous epileptiform discharges but fails in blocking them. Paradoxically, stimulus‐induced epileptiform responses are enhanced in duration during CPP application. However, concomitant application of NMDA and non‐NMDA glutamatergic antagonists abolishes spontaneous and stimulus‐induced epileptiform events. Intracellular recordings from lateral EC layer V cells indicate a lower frequency of spontaneous hyperpolarizing postsynaptic potentials in pilocarpine‐treated tissue than in NEC (P < 0.002) both under control conditions and with glutamatergic receptor blockade; the reversal potential of pharmacologically isolated GABAA receptor‐mediated inhibitory postsynaptic potentials has similar values in the two types of tissue. Finally, immunohistochemical analysis shows that parvalbumin‐positive interneurons are selectively reduced in number in EC deep layers. Collectively, these results indicate that reduced inhibition within the pilocarpine‐treated EC layer V may promote network epileptic hyperexcitability.
Diminished A‐type potassium current and altered firing properties in presympathetic PVN neurones in renovascular hypertensive rats
Authors: Sonner Patrick M. , Filosa Jessica A. , Stern Javier E.
Published: February 2008

Accumulating evidence supports a contribution of the hypothalamic paraventricular nucleus (PVN) to sympathoexcitation and elevated blood pressure in renovascular hypertension. However, the underlying mechanisms resulting in altered neuronal function in hypertensive rats remain largely unknown. Here, we aimed to address whether the transient outward potassium current (IA) in identified rostral ventrolateral medulla (RVLM)‐projecting PVN neurones is altered in hypertensive rats, and whether such changes affected single and repetitive action potential properties and associated changes in intracellular Ca2+ levels. Patch‐clamp recordings obtained from PVN‐RVLM neurons showed a reduction in IA current magnitude and single channel conductance, and an enhanced steady‐state current inactivation in hypertensive rats. Morphometric reconstructions of intracellularly labelled PVN‐RVLM neurons showed a diminished dendritic surface area in hypertensive rats. Consistent with a diminished IA availability, action potentials in PVN‐RVLM neurons in hypertensive rats were broader, decayed more slowly, and were less sensitive to the K+ channel blocker 4‐aminopyridine. Simultaneous patch clamp recordings and confocal Ca2+ imaging demonstrated enhanced action potential‐evoked intracellular Ca2+ transients in hypertensive rats. Finally, spike broadening during repetitive firing discharge was enhanced in PVN‐RVLM neurons from hypertensive rats. Altogether, our results indicate that diminished IA availability constitutes a contributing mechanism underlying aberrant central neuronal function in renovascular hypertension.
Regulation of neural KCNQ channels: signalling pathways, structural motifs and functional implications
Authors: Hernandez Ciria C. , Zaika Oleg , Tolstykh Gleb P. , Shapiro Mark S.
Published: February 2008

Neural M‐type (KCNQ/Kv7) K+channels control somatic excitability, bursting and neurotransmitter release throughout the nervous system. Their activity is regulated by multiple signalling pathways. In superior cervical ganglion sympathetic neurons, muscarinic M1, angiotensin II AT1, bradykinin B2and purinergic P2Y agonists suppress M current (IM). Probes of PLC activity show agonists of all four receptors to induce robust PIP2hydrolysis. We have grouped these receptors into two related modes of action. One mode involves depletion of phosphatidylinositol 4,5‐bisphosphate (PIP2) in the membrane, whose interaction with the channels is thought necessary for their function. The other involves IP3‐mediated intracellular Ca2+signals that stimulate PIP2synthesis, preventing its depletion, and suppressIMvia calmodulin. Carbon‐fibre amperometry can evaluate the effect of M channel activity on release of neurotransmitter. Consistent with the dominant role of M current in control of neuronal discharge, M channel openers, or blockers, reduced or augmented the evoked release of noradrenaline neurotransmitter from superior cervical ganglion (SCG) neurons, respectively. We seek to localize the subdomains on the channels critical to their regulation by PIP2. Based on single‐channel recordings from chimeras between high‐PIP2affinity KCNQ3 and low‐PIP2affinity KCNQ4 channels, we focus on a 57‐residue domain within the carboxy‐terminus that is a possible PIP2binding site. Homology modelling of this domain using the published structure of IRK1 channels as a template predicts a structure very similar to an analogous region in IRK1 channels, and shows a cluster of basic residues in the KCNQ2 domain to correspond to those implicated in PIP2regulation of Kir channels. We discuss some important issues dealing with these topics.
Pre‐ and postsynaptic plasticity underlying augmented glutamatergic inputs to hypothalamic presympathetic neurons in spontaneously hypertensive rats
Authors: Li De‐Pei , Yang Qing , Pan Hao‐Min , Pan Hui‐Lin
Published: February 2008

Increased sympathetic outflow plays an important role in the pathogenesis of hypertension. Glutamatergic inputs in the paraventricular nucleus (PVN) of the hypothalamus maintain resting sympathetic vasomotor tone in spontaneously hypertensive rats (SHR). In this study, we determined the synaptic and cellular mechanisms of increased glutamatergic inputs to PVN presympathetic neurons in SHR. The spinally projecting PVN neurons were retrogradely labelled by fluorescent microspheres injected into the intermediolateral cell column of the spinal cord. Blockade of NMDA and non‐NMDA receptors significantly decreased the firing activity of labelled PVN neurons in brain slices in SHR, but not in normotensive Wistar–Kyoto rats (WKY). The basal frequency of glutamatergic spontaneous and miniature excitatory postsynaptic currents (sEPSCs and mEPSCs, respectively) of labelled PVN neurons was significantly greater in SHR than in WKY. But the frequency of neither sEPSCs nor mEPSCs stimulated by 4‐aminopyridine or capsaicin differed significantly between WKY and SHR. Furthermore, the amplitude of postsynaptic NMDA currents elicited by either electrical stimulation or puff application in labelled PVN neurons was significantly higher in SHRs than in WKY. However, the evoked AMPA current amplitude in PVN neurons was similar in WKY and SHR. This study provides new evidence of how the glutamatergic synaptic inputs to PVN presympathetic neurons are increased and how they contribute to the elevated firing activity of these neurons in SHR. The augmented glutamatergic tone in the PVN is maintained by an increase in presynaptic glutamate release and an up‐regulation of postsynaptic NMDA receptor function in SHR.
Nervous system KV7 disorders: breakdown of a subthreshold brake
Authors: Maljevic Snezana , Wuttke Thomas V. , Lerche Holger
Published: February 2008

Voltage‐gated K+ channels of the KV7 (KCNQ) family have been identified in the last 10–15 years by discovering the causative genes for three autosomal dominant diseases: cardiac arrhythmia (long QT syndrome) with or without congenital deafness (KCNQ1), a neonatal epilepsy (KCNQ2 and KCNQ3) and progressive deafness alone (KCNQ4). A fifth member of this gene family (KCNQ5) is not affected in a disease so far. Four genes (KCNQ2–5) are expressed in the nervous system. This review is focused on recent findings on the neuronal KV7 channelopathies, in particular on benign familial neonatal seizures (BFNS) and peripheral nerve hyperexcitability (PNH, neuromyotonia, myokymia) caused by KCNQ2 mutations. The phenotypic spectrum associated with KCNQ2 mutations is probably broader than initially thought, as patients with severe epilepsies and developmental delay, or with Rolando epilepsy have been described. With regard to the underlying molecular pathophysiology, it has been shown that mutations with very subtle changes restricted to subthreshold voltages can cause BFNS thereby proving in a human disease model that this is the relevant voltage range for these channels to modulate neuronal firing. The two mutations associated with PNH induce much more severe channel dysfunction with a dominant negative effect on wild type (WT) channels. Finally, KV7 channels present interesting targets for new therapeutic approaches to diseases caused by neuronal hyperexcitability, such as epilepsy, neuropathic pain, and migraine. The molecular mechanism of KV7 activation by retigabine, which is in phase III clinical testing to treat pharmacoresistant focal epilepsies, has been recently elucidated as a stabilization of the open conformation by binding to the pore region.
The sodium‐calcium exchanger is a mechanosensitive transporter
Authors: Reeves John P. , Abdellatif Maha , Condrescu Madalina
Published: February 2008

This report describes the influence of fluid flow and osmotically induced volume changes on Na+–Ca2+ exchange (NCX) activity in transfected CHO cells. Exchange activity was measured as Na+‐dependent Ca2+ or Ba2+ fluxes using the fluorescent probe fura‐2. When exchange activity was initiated by superfusing Ba2+‐containing solutions over the cells for a 20 s interval, a high rate of Ba2+ uptake was observed while the solution was being applied but the rate of Ba2+ uptake declined > 10‐fold when the solution flow ceased. Ba2+ efflux in exchange for extracellular Na+ or Ca2+ (Ba2+–Ca2+ exchange) was similarly biphasic. During NCX‐mediated Ca2+ uptake, a rapid increase in cytosolic [Ca2+] to a peak value occurred, followed by a decline in [Ca2+]i to a lower steady‐state value after solution flow ceased. When NCX activity was initiated by an alternate procedure that minimized the duration of solution flow, the rapid phase of Ba2+ influx was greatly reduced in magnitude and Ca2+ uptake became nearly monophasic. Solution superfusion did not produce any obvious changes in cell shape or volume. NCX‐mediated Ba2+ and Ca2+ influx were also sensitive to osmotically induced changes in cell volume. NCX activity was stimulated in hypotonic media and inhibited in hypertonic media; the osmotically induced changes in activity occurred within seconds and were rapidly reversible. We conclude that NCX activity is modulated by both solution flow and osmotically induced volume changes.
Acoustic diffraction by deformed edges of finite length: Theory and experiment
Authors: Stanton Timothy K. , Chu Dezhang , Norton Guy V.
Published: February 2008

The acoustic diffraction by deformed edges of finite length is described analytically and in the frequency domain through use of an approximate line-integral formulation. The formulation is based on the diffraction per unit length of an infinitely long straight edge, which inherently limits the accuracy of the approach. The line integral is written in terms of the diffraction by a generalized edge, in that the “edge” can be a single edge or multiple closely spaced edges. Predictions based on an exact solution to the impenetrable infinite knife edge are used to estimate diffraction by the edge of a thin disk and compared with calculations based on the T-matrix approach. Predictions are then made for the more complex geometry involving an impenetrable thick disk. These latter predictions are based on an approximate formula for double-edge diffraction [Chu et al., J. Acoust. Soc. Am. 122, 3177 (2007)] and are compared with laboratory data involving individual elastic (aluminum) disks spanning a range of diameters and submerged in water. The results of this study show this approximate line-integral approach to be versatile and applicable over a range of conditions.
Geoacoustic inversion using multipath pulse shape
Authors: Prior Mark K. , Harrison Chris H. , Nielsen Peter L.
Published: February 2008

Experimental data, measured in a shallow water region of the Mediterranean Sea, are used to show that the variation of received intensity with time is well described by existing expressions [Harrison and Nielsen, J. Acoust. Soc. Am. 121, 1362–1373 (2007)]. These expressions indicate that the effect of the sea-water sound speed profile can be neglected for times greater than the peak intensity arrival. Beyond this time, intensity is shown to decay at a rate determined by the seabed acoustic properties in a manner very similar to that for an isovelocity water column. It is shown that a method of determining seabed acoustic properties, previously restricted to isovelocity water columns [Prior and Harrison, J. Acoust. Soc. Am. 116, 1341–1344 (2004)], can consequently be used in the presence of a sound-speed profile. The method relates the decay rate of smeared multipath arrivals to the angular derivative of seabed reflection loss. Two datasets are studied and the method is used to describe average seabed properties and to detect changes in seabed type. The seabed descriptions thus derived are used to predict total received intensity as a function of source-receiver separation. Agreement between the propagation measurements and predictions is shown to be within measurement uncertainties.
Development of a micromachined piezoelectric microphone for aeroacoustics applications
Authors: Horowitz Stephen , Nishida Toshikazu , Cattafesta Louis , Sheplak Mark
Published: February 2008

This paper describes the design, fabrication, and characterization of a bulk-micromachined piezoelectric microphone for aeroacoustic applications. Microphone design was accomplished through a combination of piezoelectric composite plate theory and lumped element modeling. The device consists of a 1.80-mm-diam, 3-μm-thick, silicon diaphragm with a 267-nm-thick ring of piezoelectric material placed near the boundary of the diaphragm to maximize sensitivity. The microphone was fabricated by combining a sol-gel lead zirconate-titanate deposition process on a silicon-on-insulator wafer with deep-reactive ion etching for the diaphragm release. Experimental characterization indicates a sensitivity of 1.66μV∕Pa, dynamic range greater than six orders of magnitude (35.7–169dB, re 20μPa), a capacitance of 10.8nF, and a resonant frequency of 59.0kHz.
Modeling scattering from azimuthally symmetric bathymetric features using wavefield superposition
Authors: Fawcett John A.
Published: February 2008

In this paper, an approach for modeling the scattering from azimuthally symmetric bathymetric features is described. These features are useful models for small mounds and indentations on the seafloor at high frequencies and seamounts, shoals, and basins at low frequencies. A bathymetric feature can be considered as a compact closed region, with the same sound speed and density as one of the surrounding media. Using this approach, a number of numerical methods appropriate for a partially buried target or facet problem can be applied. This paper considers the use of wavefield superposition and because of the azimuthal symmetry, the three-dimensional solution to the scattering problem can be expressed as a Fourier sum of solutions to a set of two-dimensional scattering problems. In the case where the surrounding two half spaces have only a density contrast, a semianalytic coupled mode solution is derived. This provides a benchmark solution to scattering from a class of penetrable hemispherical bosses or indentations. The details and problems of the numerical implementation of the wavefield superposition method are described. Example computations using the method for a simple scattering feature on a seabed are presented for a wide band of frequencies.