bluuebunny/crossref_metadata_2025 huggingface dataset:
Perennial stream discharge in the hyperarid Atacama Desert of northern Chile during the latest Pleistocene
Authors: Nester Peter L. , Gayó Eugenia , Latorre Claudio , Jordan Teresa E. , Blanco Nicolás
Published: December 2007

A large fraction of the vital groundwater in the Atacama Desert of northern Chile is likely composed of “fossil” or “ancient” reserves that receive little or no recharge in today's hyperarid climate. Here, we present evidence for latest Pleistocene perennial streamflow in canyons from the hyperarid core of the Atacama Desert in northern Chile. Fluvial terraces in the Pampa del Tamarugal (PdT) basin (21°S) contain widespread fossil wood,
in situ
roots, and well preserved leaf litter deposits indicative of perennial surface flow currently absent in these channels. Nineteen radiocarbon dates on these deposits from four separate drainages within this endorheic basin indicate ages from 16,380 to 13,740 cal yr BP, synchronous with paleolake Tauca on the Bolivian Altiplano and other regional evidence for wetter conditions during the latest Pleistocene. Groundwater-fed riparian ecosystems and associated fluvial deposits abound today in the absence of direct rainfall in northern Atacama canyons with perennial discharge. Our relict riparian ecosystems from the PdT basin are indicative of conditions similar to these northern canyons. Given that discharge was higher than present during this time, we propose that these deposits represent the most important groundwater recharge events of the last 18,000 years. A lesser recharge event occurred during the Holocene, when phreatophytic trees also grew in these drainages between 1,070 and 700 cal yr BP, during the Medieval Climatic Anomaly. Taken together, our evidence lends further support for gradient changes in the equatorial Pacific as a major driver of hydrologic change in the Atacama on both centennial and millennial time scales.
Observational evidence for volcanic impact on sea level and the global water cycle
Authors: Grinsted A. , Moore J. C. , Jevrejeva S.
Published: December 2007

It has previously been noted that there are drops in global sea level (GSL) after some major volcanic eruptions. However, observational evidence has not been convincing because there is substantial variability in the global sea level record over periods similar to those at which we expect volcanoes to have an impact. To quantify the impact of volcanic eruptions we average monthly GSL data from 830 tide gauge records around five major volcanic eruptions. Surprisingly, we find that the initial response to a volcanic eruption is a significant rise in sea level of 9 ± 3 mm in the first year after the eruption. This rise is followed by a drop of 7 ± 3 mm in the period 2–3 years after the eruption relative to preeruption sea level. These results are statistically robust and no particular volcanic eruption or ocean region dominates the signature we find. Neither the drop nor especially the rise in GSL can be explained by models of lower oceanic heat content. We suggest that the mechanism is a transient disturbance of the water cycle with a delayed response of land river runoff relative to ocean evaporation and global precipitation that affects global sea level. The volcanic impact on the water cycle and sea levels is comparable in magnitude to that of a large El Niño–La Niña cycle, amounting to ≈5% of global land precipitation.
Circuit theory predicts gene flow in plant and animal populations
Authors: McRae Brad H. , Beier Paul
Published: December 2007

Maintaining connectivity for broad-scale ecological processes like dispersal and gene flow is essential for conserving endangered species in fragmented landscapes. However, determining which habitats should be set aside to promote connectivity has been difficult because existing models cannot incorporate effects of multiple pathways linking populations. Here, we test an ecological connectivity model that overcomes this obstacle by borrowing from electrical circuit theory. The model vastly improves gene flow predictions because it simultaneously integrates all possible pathways connecting populations. When applied to data from threatened mammal and tree species, the model consistently outperformed conventional gene flow models, revealing that barriers were less important in structuring populations than previously thought. Circuit theory now provides the best-justified method to bridge landscape and genetic data, and holds much promise in ecology, evolution, and conservation planning.
An androgen-regulated miRNA suppresses Bak1 expression and induces androgen-independent growth of prostate cancer cells
Authors: Shi Xu-Bao , Xue Lingru , Yang Joy , Ma Ai-Hong , Zhao Jianjun , Xu Ma , Tepper Clifford G. , Evans Christopher P. , Kung Hsing-Jien , deVere White Ralph W.
Published: December 2007

Although prostate cancer (CaP) is the most frequently diagnosed malignant tumor and the second leading cause of cancer deaths in American men, the mechanisms explaining the development and progression of CaP remain largely unknown. Recent studies have shown that some aberrantly expressed microRNAs (miRNAs) are involved in tumorigenesis. Although aberrant expression of certain miRNAs has been discovered in CaP, their function in this disease has not yet been defined. In this study, we found differential expression of
miR-125b
in androgen-dependent and independent CaP cells, as well as in benign and malignant prostate tissues. Furthermore, androgen signaling was able to up-regulate the expression of
miR-125b
. In addition, transfection of synthetic miR-125b stimulated androgen-independent growth of CaP cells and down-regulated the expression of Bak1. Our results suggest that
miR-125b
acts as an oncogene, contributing to the pathogenesis of CaP.
Anterior temporal lobes mediate semantic representation: Mimicking semantic dementia by using rTMS in normal participants
Authors: Pobric Gorana , Jefferies Elizabeth , Ralph Matthew A. Lambon
Published: December 2007

Studies of semantic dementia and PET neuroimaging investigations suggest that the anterior temporal lobes (ATL) are a critical substrate for semantic representation. In stark contrast, classical neurological models of comprehension do not include ATL, and likewise functional MRI studies often fail to show activations in the ATL, reinforcing the classical view. Using a novel application of low-frequency, repetitive transcranial magnetic stimulation (rTMS) over the ATL, we demonstrate that the behavioral pattern of semantic dementia can be mirrored in neurologically intact participants: Specifically, we show that temporary disruption to neural processing in the ATL produces a selective semantic impairment leading to significant slowing in both picture naming and word comprehension but not to other equally demanding, nonsemantic cognitive tasks.
Competitive release and facilitation of drug-resistant parasites after therapeutic chemotherapy in a rodent malaria model
Authors: Wargo Andrew R. , Huijben Silvie , de Roode Jacobus C. , Shepherd James , Read Andrew F.
Published: December 2007

Malaria infections frequently consist of mixtures of drug-resistant and drug-sensitive parasites. If crowding occurs, where clonal population densities are suppressed by the presence of coinfecting clones, removal of susceptible clones by drug treatment could allow resistant clones to expand into the newly vacated niche space within a host. Theoretical models show that, if such competitive release occurs, it can be a potent contributor to the strength of selection, greatly accelerating the rate at which resistance spreads in a population. A variety of correlational field data suggest that competitive release could occur in human malaria populations, but direct evidence cannot be ethically obtained from human infections. Here we show competitive release after pyrimethamine curative chemotherapy of acute infections of the rodent malaria
Plasmodium chabaudi
in laboratory mice. The expansion of resistant parasite numbers after treatment resulted in enhanced transmission-stage densities. After the elimination or near-elimination of sensitive parasites, the number of resistant parasites increased beyond that achieved when a competitor had never been present. Thus, a substantial competitive release occurred, markedly elevating the fitness advantages of drug resistance above those arising from survival alone. This finding may explain the rapid spread of drug resistance and the subsequently brief useful lifespans of some antimalarial drugs. In a second experiment, where subcurative chemotherapy was administered, the resistant clone was only partly released from competitive suppression and experienced a restriction in the size of its expansion after treatment. This finding raises the prospect of harnessing in-host ecology to slow the spread of drug resistance.
Ubiquitin-dependent virus particle budding without viral protein ubiquitination
Authors: Zhadina Maria , McClure Myra O. , Johnson Marc C. , Bieniasz Paul D.
Published: December 2007

An essential step in the release of an extracellular enveloped virus particle is a budding event that ultimately separates virion and host cell membranes. For many enveloped viruses, membrane fission requires the recruitment of the class E vacuolar protein sorting (VPS) machinery by short, virally encoded peptide sequences termed “late-budding” or “L” domains. Some L-domain peptide sequences (e.g., PSAP) bind directly to components of class E VPS machinery, whereas others (e.g., PPxY) access it indirectly by recruiting ubiquitin ligases. Additionally, ubiquitin itself is known to be generally important for the fission of virion from cellular membranes, and because ubiquitination of cellular transmembrane proteins can signal the recruitment of class E machinery, a popular model is that deposition of ubiquitin on viral structural proteins mediates class E machinery recruitment. To test this model, we took advantage of a retroviral Gag protein from the prototypic foamy virus (PFV) that is almost devoid of ubiquitin acceptors, and we engineered it to generate extracellular virus-like particles in the complete absence of other viral proteins. Notably, we found that particle budding, induced by a class E VPS machinery-binding L domain (PSAP), proceeded efficiently in the absence of ubiquitin acceptors in PFV Gag. Moreover, when particle release was engineered to be dependent on a viral PPXY motif, the requirement for a catalytically active ubiquitin ligase was maintained, irrespective of the presence or absence of ubiquitin acceptor sites in PFV Gag. Thus, in this model system, ubiquitin conjugation to transacting factors, not viral proteins, appears critical for ubiquitin-dependent enveloped viral particle release.
Signal sequence mutation in autosomal dominant form of hypoparathyroidism induces apoptosis that is corrected by a chemical chaperone
Authors: Datta Rupak , Waheed Abdul , Shah Gul N. , Sly William S.
Published: December 2007

Autosomal dominant familial isolated hypoparathyroidism (AD-FIH) is caused by a Cys → Arg mutation (C18R) in the hydrophobic core of the signal peptide of human preproparathyroid hormone (PPTH). Although this mutation impairs secretion of the hormone, the mechanism by which one mutant allele produces the autosomal-dominant disease is unexplained. Using transfected HEK293 cells, we demonstrate that the expressed mutant hormone is trapped intracellularly, predominantly in the endoplasmic reticulum (ER). This ER retention was found to be toxic for the cells, which underwent apoptosis, as evident from the marked increase in the number of cells staining positive for Annexin V binding and for the TUNEL reaction. The cells producing mutant hormone also had marked up-regulation of the ER stress-responsive proteins, BiP and PERK, as well as the proapoptotic transcription factor, CHOP. Up-regulation of these markers of the unfolded protein response supported a causal link between the ER stress and the cell death cascade. When the C18R PPTH was expressed in the presence of 4-phenylbutyric acid, which is a pharmacological chaperone, intracellular accumulation was reduced and normal secretion was restored. This treatment also produced remarkable reduction of ER stress signals and protection against cell death. These data implicate ER stress-induced cell death as the underlying mechanism for AD-FIH and suggest that the pharmacological manipulation of this pathway by using chemical chaperones offers a therapeutic option for treating this disease.
Mammary epithelial-specific disruption of the focal adhesion kinase blocks mammary tumor progression
Authors: Lahlou Hicham , Sanguin-Gendreau Virginie , Zuo Dongmei , Cardiff Robert. D. , McLean Gordon W. , Frame Margaret C. , Muller William J.
Published: December 2007

Elevated expression and activation of the focal adhesion kinase (FAK) occurs in a large proportion of human breast cancers. Although several studies have implicated FAK as an important signaling molecule in cell culture systems, evidence supporting a role for FAK in mammary tumor progression is lacking. To directly assess the role of FAK in this process, we have used the Cre/loxP recombination system to disrupt FAK function in the mammary epithelium of a transgenic model of breast cancer. Using this approach, we demonstrate that FAK expression is required for the transition of premalignant hyperplasias to carcinomas and their subsequent metastases. This dramatic block in tumor progression was further correlated with impaired mammary epithelial proliferation. These observations provide direct evidence that FAK plays a critical role in mammary tumor progression.
Two forces for arousal: Pitting hunger versus circadian influences and identifying neurons responsible for changes in behavioral arousal
Authors: Ribeiro Ana C. , Sawa Evelyn , Carren-LeSauter Isabelle , LeSauter Joseph , Silver Rae , Pfaff Donald W.
Published: December 2007

The mechanisms underlying CNS arousal in response to homeostatic pressures are not known. In this study, we pitted two forces for CNS arousal against each other (circadian influences vs. restricted food availability) and measured the neuronal activation that occurs in a behaviorally defined group of animals that exhibited increased arousal in anticipation of feeding restricted to their normal sleeping time. The number of c-FOS+ neurons was significantly increased only in the ventromedial nucleus of the hypothalamus (VMH) in these mice, compared with control animals whose feeding was restricted to their normal active and feeding time (
P
< 0.01). Because the activation of VMH neurons coincides with the earliest signs of behavioral arousal preceding a change in meal time, we infer that VMH activation is involved in the increased arousal in anticipation of food.
Multiple, conserved cryptic recombination signals in VH gene segments: detection of cleavage products only in pro–B cells
Authors: Davila Marco , Liu Feifei , Cowell Lindsay G. , Lieberman Anne E. , Heikamp Emily , Patel Anjali , Kelsoe Garnett
Published: December 2007

Receptor editing is believed to play the major role in purging newly formed B cell compartments of autoreactivity by the induction of secondary V(D)J rearrangements. In the process of immunoglobulin heavy (H) chain editing, these secondary rearrangements are mediated by direct VH-to-JH joining or cryptic recombination signals (cRSs) within VH gene segments. Using a statistical model of RS, we have identified potential cRSs within VH gene segments at conserved sites flanking complementarity-determining regions 1 and 2. These cRSs are active in extrachromosomal recombination assays and cleaved during normal B cell development. Cleavage of multiple VH cRSs was observed in the bone marrow of C57BL/6 and RAG2:GFP and μMT congenic animals, and we determined that cRS cleavage efficiencies are 30–50-fold lower than a physiological RS. cRS signal ends are abundant in pro–B cells, including those recovered from μMT mice, but undetectable in pre– or immature B cells. Thus, VH cRS cleavage regularly occurs before the generation of functional preBCR and BCR. Conservation of cRSs distal from the 3′ end of VH gene segments suggests a function for these cryptic signals other than VH gene replacement.
The Worlds of Frantz Fanon's ‘L’Algérie se dévoile'
Authors: Reid Donald
Published: December 2007

Frantz Fanon's pioneering essay ‘L’Algérie se dévoile' is enriched by examining the particular situation of a few exceptional Algerian and French women prominent in Algeria during the War of Independence who are not the focus of Fanon's analysis, individuals like the FLN militant Zohra Drif and General Jacques Massu's wife, Suzanne Massu. They were quite unrepresentative of Algerian or French women in Algeria, but crucial figures in representations of activists in each group. Drif, a gifted student from the social elite, had, like Fanon, been exposed in French cultural institutions to a liberation at once proffered and denied. If there is little place for her experience in Fanon's essay, he does show what we can learn about the contemporary French
mentalité
from assessment of characters inspired by women like Drif in novels about the war. Examination of Suzanne Massu in turn suggests how bourgeois French women empowered in maternalist projects could work to try to impede Algerian women's embrace of national liberation, but not through the putative liberation of women Fanon addresses. The war unveiled a yet more complicated world of imagination and practices than we see in Fanon's essay.
‘Doctrine moult paradoxe et nouvelle’: Linguistic and Medical Innovation in Rabelais's
Tiers Livre
Authors: Steczowicz Agnieszka
Published: December 2007

One hitherto neglected avenue to the study of sixteenth-century paradoxes is through the history of the word. Focusing on Rabelais's use of the adjective
paradoxe
in the
Tiers Livre
(1546), this article proposes to examine the earliest known occurrences of the word in the French language. Why does Rabelais use it for the first time in the
Tiers Livre
, and why are nearly all the occurrences of this term in his work confined to the
Tiers Livre
? Rabelais may have been influenced, as critics have noted, by Ortensio Lando's
Paradossi
, a collection of mock encomia published in Lyon in 1543, and by the anonymous
Paradoxe contre les lettres
(1545), whose authorship has been attributed to Maurice Scève. But he may also, I argue, have drawn on learned Latin and vernacular paradoxes, as exemplified by works of Cicero, Andrea Alciato and Leonhart Fuchs, which were published in Lyon at the time by Sébastien Gryphe and Jean de Tournes. To illustrate the impact that these paradoxes had on Rabelais's thought, I turn to medical paradoxes and follow the traces of one particular medical controversy, regarding suppers and lunches and which should be the lighter of the two meals, in Rabelais's fictional writings.
Mathieu Kassovitz's
La Haine
and the Ambivalence of French–Jewish Identity
Authors: Rose Sven-Erik
Published: December 2007

From the 1995 release of
La Haine
, critics have questioned whether Jewish-French film director Mathieu Kassovitz is ‘authentic enough’ to speak for the ethnic
banlieue
. Yet
La Haine
is preoccupied with this very anxiety. This article examines how the film self-reflexively explores the place of Jewishness in the social crisis it dramatizes.
La Haine
achieves this ‘Jewish’ self-reflexivity primarily through the relationship its arguably most fully realized character, Vinz (a working-class Ashkenazi Jew), entertains to his more visibly ethnic friends Saïd (an Arab) and Hubert (a black African). As Vinz navigates the complicated terrain of adolescent relationships striving to become ‘real’, in other words, ethnic, masculine, authentic, the film also searches for a place for Jewish identity a generation after the ambivalent Jewish encounter with May 1968 and beyond. Vinz's ambivalent locus between, on the one hand, other minority figures with whom he wishes problematically to identify and, on the other, the privilege of whiteness vis-à-vis which he occupies a position of complex and uneasy proximity exemplifies a wider crisis of French Jews on the Left. The article concludes with a discussion of this crisis and how
La Haine
situates itself in the history of post-war Left Jewish politics in France.
Touch, Translation, Witness in Alberto Giacometti,
La Main
,
Le Nez
Authors: Mathews Timothy
Published: December 2007

In the period from the late 1930s to the late 1940s, spanning the Second World War, Giacometti embarks on his attempts to represent the human form. He discovers his inability to locate the human form in space. How then can human experience be witnessed? What is at stake in transposing, translating one experience into another? Aesthetic concerns activate moral ones by failing to occupy the same place. This creates an experience of responsibility which arises through engagement with the formal presence of aesthetic artefacts; and also through the act itself of comparison. This essay responds by placing two pieces by Giacometti in a critical vicinity with works by Nancy and Blanchot exploring the failure to locate in touch, on the one hand, and in time, on the other.
Herring and the “Exxon Valdez” oil spill: an investigation into historical data conflicts
Authors: Thorne Richard E. , Thomas Gary L.
Published: December 2007

Thorne, R. E., and Thomas, G. L. 2008. Herring and the "Exxon Valdez" oil spill: an investigation into historical data conflicts. – ICES Journal of Marine Science, 65: 44–50. It was generally believed that the 1989 “Exxon Valdez” oil spill did not cause the collapse of the Prince William Sound Pacific herring (Clupea pallasi) population because of a 4-year gap between the spill and the collapse. However, we noted in a previous paper that some data suggested an earlier timing for the herring decline. We examine historical patterns of herring spawn, anomalies in historical fisheries model predictions, changes in predation behaviour of Steller sea lions (Eumetopias jubatus), and a decadal database of acoustic measurements of herring biomass. Behaviour of adult herring makes them especially vulnerable to damage from oil spills, something that was either unknown or misunderstood at the time of the spill. We therefore argue that the start of the herring decline was coincident with the oil spill, and that the decline took place over a 5-year period, rather than the single-year collapse previously reported. Although a comprehensive management approach is now in use for herring, the tools were not in place at the time of the oil spill or the subsequent collapse.
Daytime steady‐state haemoglobin desaturation is a risk factor for overt stroke in children with sickle cell anaemia
Authors: Quinn Charles T. , Sargent James W.
Published: December 2007

Haemoglobin (Hb) desaturation could increase the risk of stroke in sickle cell anaemia (SS) by perturbing endothelial function and limiting oxygen delivery to the brain. We performed a nested case–control study of the Dallas Newborn Cohort to determine whether daytime steady‐state Hb desaturation was associated with overt stroke in children with SS. Cases had SS and overt ischaemic strokes. Controls had comparable genotypes but no overt stroke. Cases had lower prestroke steady‐state pulse oximetry values (SpO2) than controls, and cases’ SpO2 fell even lower as the time to impending stroke decreased. The odds ratio for stroke was 1·32 for each 1% decrease in SpO2. In conclusion, steady‐state Hb desaturation is a risk factor for overt ischaemic stroke in children with SS. Decline in SpO2 over time further increases this risk. Hb desaturation is easily measured, potentially modifiable, and could be used to identify children with SS at increased risk of stroke.
Bottom‐up cascading effects in a tritrophic system: interactions between plant quality and host‐parasitoid immune responses
Authors: KARIMZADEH JAVAD , WRIGHT DENIS J.
Published: December 2007

Abstract1. Little is known about underlying mechanisms by which plants indirectly affect parasitism success in hymenopteran endoparasitoids. The hypothesis thathost‐plant effects can challenge the innate immune system of an insect hostwas experimentally tested in this study using a model tritrophic, crucifer – lepidopteran [Plutella xylostella(L.)] – parasitoid [Cotesia plutellae(Kurdjumov)], system.

2. The effects of host‐plant suitability on herbivore performance and parasitism were examined. The bottom‐up effect of plant suitability on host‐parasitoid immune responses was then evaluated using measures of cellular and humoral effectors.

3. Host‐plant quality showed a significant effect on the encapsulation response ofP. xylostellato first instar but not to second instar parasitoid larvae. Encapsulation was never sufficient to prevent parasitoid emergence.

4. Poor host‐plant suitability suppressed phenoloxidase activity in the absence of the parasitoid. The suppressive effect ofC. plutellaeon phenoloxidase activity was much greater and no plant effects were detectable after insects had been parasitized.

5. Despite strong plant effects on parasitism, those on immune effectors of the host were transitory or overwhelmed by the effect of the parasitoid.

6. These results demonstrated that plant‐mediated variation in parasitism success byC. plutellaewere not as a result of plant nutritional status or other attributes affecting the immune function ofP. xylostella, nor to host‐plant effects on superparasitism.

7. In these experiments,P. xylostellawas a fully permissive host toC. plutellaeand host‐plant‐mediated effects on the innate immune response appeared to play no part in parasitoid survival within hosts.
The effect of pH on surface hardness and microstructure of mineral trioxide aggregate
Authors: Namazikhah M. S. , Nekoofar M. H. , Sheykhrezae M. S. , Salariyeh S. , Hayes S. J. , Bryant S. T. , Mohammadi M. M. , Dummer P. M. H.
Published: December 2007

Aim  To evaluate the surface microhardness of mineral trioxide aggregate (MTA) specimens following exposure of their surface to a range of acidic environments during hydration. In addition, the morphological microstructure features of samples were studied by scanning electron microscopy (SEM).

Methodology  White ProRoot MTA (Dentsply Tulsa Dental, Johnson City, TN, USA) was mixed and packed into cylindrical polycarbonate tubes. Four groups, each of 10 specimens, were formed using a pressure of 3.22 MPa and exposed to pH 4.4, 5.4, 6.4 and 7.4, respectively, for 4 days. Vickers microhardness of the surface of each specimen was measured after exposure. Four groups of two specimens were prepared and treated in the same way prior to qualitative examination by SEM. Data were subjected to one‐way anova and post hoc Tukey’s test.

Result  The greatest mean surface hardness values (53.19 ± 4.124) were observed following exposure to pH 7.4 with the values decreasing to 14.34 ± 6.477 following exposure to pH 4.4. The difference between these values at the 95% CI (33.39–44.30) was statistically significant (P < 0.0001). There were no distinct morphological differences between groups in terms of the internal microstructure. However, a trend was observed that the more acidic the solution, the more extensive the porosity of the specimens.

Conclusion  Under the conditions of this study, surface hardness of MTA was impaired in an acidic environment.
Androgen receptor CAG repeats and body composition among Ariaal men
Authors: Campbell Benjamin C. , Gray Peter B. , Eisenberg Dan T. A. , Ellison Peter , Sorenson Michael D.
Published: December 2007

To determine the population variation in the androgen receptor (AR) and its association with body composition in a subsistence population, we sampled 87 settled and 65 nomadic males ages 20+ among the Ariaal of northern Kenya. Anthropometric measures included height, body mass index, fat‐free mass (FFM), upper arm muscle plus bone area (AMPBA), % body fat (%BF), suprailliac skinfold (SISF), and waist‐to‐hip ratio. Salivary testosterone (T) was determined from both morning (Am T) and afternoon (Pm T) samples. Hair roots were obtained for genotyping AR CAG repeat length. AR CAG repeat length did not vary between the two sub‐groups (overall value = 22.6 ± 3.1). Multiple regression models, controlling for age and residence, indicate that Pm T was positively associated with all measures of body composition. AR CAG repeat length was a significant positive predictor of height, FFM, %BF, SISF and waist circumference. There was a significant negative Pm T by AR CAG repeat length interaction in predicting all anthropometric measures but AMPBA. These findings provide evidence for population variation in AR CAG repeat length and suggest that both T and AR CAG length play a role in body composition in this extremely lean population.
Preliminary characterisation of peach cultivars for their antioxidant capacity
Authors: Tavarini Silvia , Degl’Innocenti Elena , Remorini Damiano , Massai Rossano , Guidi Lucia
Published: December 2007

Eleven peach cultivars (white‐ and yellow‐flesh peaches, nectarines and canning clingstone peaches) were assayed for their antioxidant capacity and their content of some important organic compounds as well as vitamin C, carotenoids and phenols. Antioxidant capacity, determined by FRAP assay, varied between genotypes. Those with the highest value of Ferric Reducing Antioxidant Power (FRAP) were Federica and Springcrest. Antioxidant capacity was correlated to the amount of organic components with significant differences among the cultivars. In some case, antioxidant capacity was related to phenol content, as in yellow–flesh peaches. These results suggest the importance of genotype for determining antioxidant capacity, which, in turn, is related to the organic constituents, such as phenols, vitamin C and carotenoids.
Prognostication of tempering time in wheat conditioning by dielectric heating
Authors: Krasteva Ana , Petrova Nadezhda , Aljoshev Peter
Published: December 2007

From the investigations done concerning the change of the basic milling indices in wheat conditioning by dielectric heating it has been established that the hectolitre weight in wheat variety with 32%, 52% and 84% of vitreousness decreases up to the third hour for the first two wheat varieties and to the fourth hour for the third variety, after which the values were constant. The index of wheat vitreousness increases to the second hour for the low‐vitreous wheat variety, to the fourth hour for the medium‐vitreous wheat variety and to the fifth hour in the highly vitreous wheat variety. After these hours, the vitreous values were constant. The dependence between tempering time and the indices of vitreousness and hectolitre weight in wheat conditioning by dielectric heating has been investigated. From the regression equations that were obtained, it is possible to prognosticate the tempering time by pre‐setting values of the indices at the vitreousness and their respective moistures that were studied.
An evaluation of the retention of quality characteristics in fresh and freeze‐dried alpine strawberries
Authors: Yurdugül Seyhun
Published: December 2007

Alpine strawberries (Fragaria vesca) are used in fruit juice, marmalade, or jam production and as a result have economical importance in food sector. The fresh alpine strawberries have a tendency to lose their quality in a few days as a result of high water loss and spoilage. In this paper, the results of a study on the effects of freeze drying process on the characteristics of the alpine strawberries, such as firmness, sugar content, pH, colour, weight loss, dissolved solids, anthocyanin and vitamin C content with reference to the fresh, are reported. Freeze‐drying indicated no difference in the characteristics of the alpine strawberries when compared with the fresh. It is found that a slight acid or base addition onto the rehydrated alpine strawberry juice preserved the stability of pigments and the colour. In addition, the rehydrated alpine strawberry juice exhibited an antimicrobial activity towards an important foodborne pathogen, Enterobacter faecium ATCC 6057.
Process development of a chocolate‐flavoured peanut–soy beverage
Authors: Deshpande Rashmi P. , Chinnan Manjeet S. , Phillips Robert D.
Published: December 2007

A new beverage product was developed utilising two protein‐rich oilseed sources, namely peanut and soy. Medium‐roasted peanut flour and chocolate flavour were incorporated to offer pleasant flavour profile. The peanut–soy combination would also improve essential amino acid profile, especially that of lysine, compared with an all‐peanut product. A pilot‐plant scale beverage‐processing protocol involved filtration, homogenisation and pasteurisation as the major operating steps. Beverage formulation employed a three‐component constrained mixture design. The low‐ and high‐bound constraints were determined for peanut (30.6–58.7%), soy (28.3–43.5%) and chocolate syrup (13.0–25.9%) based on lysine content, viscosity and visual stability index values of 51‐mg g−1 protein, 36.9 mPa s and 1.00, respectively. The beverage formulation and processing protocol thus developed were the basis for further study on consumer acceptability of the new chocolate‐flavoured peanut–soy beverage.
Thermodynamic properties of moisture desorption of raw pinhão (Araucaria angustifolia seeds)
Authors: Cladera‐Olivera Florencia , Pettermann Ana Carolina , Noreña Caciano Pelayo Zapata , Wada Keiko , Marczak Ligia Damasceno Ferreira
Published: December 2007

The seeds of Araucaria angustifolia, named pinhão, are consumed in the south and southeast of Brazil. They are big in size and have high nutritious value. The literature about technological aspects of pinhão is very scarce and there are no reports about moisture sorption models. In this work, moisture desorption isotherms of raw pinhão were determined at 15, 25, 30 and 40 °C. Results show that temperature has little effect on the sorption behaviour and the Chirife model was found to best represent the experimental data. The isosteric heat of sorption (differential enthalpy) was calculated through direct use of moisture desorption isotherm by applying the Clausius‐Clapeyron equation. The differential enthalpy of desorption decreased with increasing moisture content. The enthalpy–entropy compensation theory was applied to desorption isotherms and plots of differential enthalpy vs. differential entropy for pinhão provided the isokinetic temperature, indicating an enthalpy‐controlled desorption process.
Nonenzymatic browning of selected fruit juices affected by D‐galacturonic acid
Authors: Ibarz Albert , Garza Salvador , Pagán Jordi
Published: December 2007

This work studies the effect of d‐galacturonic acid (AGA) on the non‐enzymatic browning of three types of clarified concentrated fruit juices (apple, pear and peach). It was observed that the presence of AGA increases the browning of juices. This was evaluated by the evolution of the absorbance at 420 nm (A420) with the treatment time that these juices show. The evolution at A420 over time was fitted to first‐order kinetics and it was observed that the kinetic constant values increased with both the increase in the AGA content and the rise in the treatment. The effect of the temperature treatment on the non‐enzymatic browning of these juices was quantified by fitting the variation of the kinetic constants with the Arrehnius equation, thus obtaining the corresponding activation energies. In the case of apple juice, it was observed that for the increase in AGA content the activation energy increases considerably, while for the pear and peach juices, a slight increase of the activation energy was observed with the increase in AGA.
Characteristics of pigment composition and colour value by the difference of harvesting times in Korean red pepper varieties (Capsicum annuum, L.)
Authors: Kim Suna , Youl Ha Tae , Park Jaebok
Published: December 2007

The main pigments of Capsicum annuum cv. Hanbando and Dabotop in dried red fruits were capsanthin, zeaxanthin, beta‐cryptoxanthin and beta‐carotene. Total carotenoid contents were twice as high at the fourth harvest compared with the second harvest in both varieties. The ratios of capsanthin to yellow fraction were above 1.0 in Hanbando and below 1.0 in Dabotop. Zeaxanthin content at the third harvest was about three times higher than at the second harvest in Dabotop. ASTA colour values harvested in the second, third and fourth weeks were 114, 152 and 178 in Hanbando and 115, 137 and 140 in Dabotop. Hue value of Hanbando was below 1.0 at all harvests and that of Dabotop was above 1.0 at the second and fourth harvests. The comparison of the C* values of two varieties revealed that Hanbando had the most vivid redness at the fourth harvest, whereas Dabotop was most vivid at the second harvest.
Statistical modelling of the geometry of planar sections of prostatic capillaries on the basis of stationary Strauss hard‐core processes
Authors: MATTFELDT TORSTEN , ECKEL STEFANIE , FLEISCHER FRANK , SCHMIDT VOLKER
Published: December 2007

In a recent study, the capillarization of normal prostatic tissue and prostatic carcinoma tissue was characterized by means of explorative methods of spatial statistics. In the present paper, an attempt was made to go beyond the explorative approach and to characterize the observed point patterns of the capillary profiles on sections by means of a parametric model. For this purpose, the flexible class of Gibbs processes was considered. Specifically, stationary Strauss hard‐core processes were fitted to the observed point patterns. The goodness of fit achieved by the model was checked by simulations with the Markov chain Monte Carlo method using the Metropolis–Hastings algorithm. Model fitting and simulations were performed with the help of thespatstatpackage under R. The observed point patterns were in some cases compatible with realizations of stationary Strauss hard‐core processes for all ranges of spatial interaction. However, deviations from the model were found for one or more domains of ranges in other cases. In the tumour tissue, a highly significant decrease of the interaction parameter of the Strauss hard‐core process could be found as compared to the normal prostatic tissue. This finding is discussed in terms of a loss of the normal lobular architecture of the glands in the tumour tissue.
Analytic solutions to modelling exponential and harmonic functions using Chebyshev polynomials: fitting frequency‐domain lifetime images with photobleaching
Authors: MALACHOWSKI GEORGE C. , CLEGG ROBERT M. , REDFORD GLEN I.
Published: December 2007

A novel approach is introduced for modelling linear dynamic systems composed of exponentials and harmonics. The method improves the speed of current numerical techniques up to 1000‐fold for problems that have solutions of multiple exponentials plus harmonics and decaying components. Such signals are common in fluorescence microscopy experiments. Selective constraints of the parameters being fitted are allowed. This method, using discrete Chebyshev transforms, will correctly fit large volumes of data using a noniterative, single‐pass routine that is fast enough to analyse images in real time. The method is applied to fluorescence lifetime imaging data in the frequency domain with varying degrees of photobleaching over the time of total data acquisition. The accuracy of the Chebyshev method is compared to a simple rapid discrete Fourier transform (equivalent to least‐squares fitting) that does not take the photobleaching into account. The method can be extended to other linear systems composed of different functions. Simulations are performed and applications are described showing the utility of the method, in particular in the area of fluorescence microscopy.
The Large‐Scale Digital Cell Analysis System: an open system for nonperturbing live cell imaging
Authors: DAVIS PAUL J. , KOSMACEK ELIZABETH A. , SUN YUANSHENG , IANZINI FIORENZA , MACKEY MICHAEL A.
Published: December 2007

The Large‐Scale Digital Cell Analysis System (LSDCAS) was designed to provide a highly extensible open source live cell imaging system. Analysis of cell growth data has demonstrated a lack of perturbation in cells imaged using LSDCAS, through reference to cell growth data from cells growing in CO2incubators. LSDCAS consists of data acquisition, data management and data analysis software, and is currently a Core research facility at the Holden Comprehensive Cancer Center at the University of Iowa. Using LSDCAS analysis software, this report and others show that although phase‐contrast imaging has no apparent effect on cell growth kinetics and viability, fluorescent image acquisition in the cell lines tested caused a measurable level of growth perturbation using LSDCAS. This report describes the current design of the system, reasons for the implemented design, and details its basic functionality. The LSDCAS software runs on the GNU/Linux operating system, and provides easy to use, graphical programs for data acquisition and quantitative analysis of cells imaged with phase‐contrast or fluorescence microscopy (alone or in combination), and complete source code is freely available under the terms of the GNU Public Software License at the project website (http://lsdcas.engineering.uiowa.edu).
Can scanning near‐field optical microscopy be compared with confocal laser scanning microscopy? A preliminary study on α‐sarcoglycan and β1D‐integrin in human skeletal muscle
Authors: ANASTASI G. , CUTRONEO G. , PISANI A. , BRUSCHETTA D. , MILARDI D. , PRINCI P. , GUCCIARDI P.G. , BRAMANTI P. , SOSCIA L. , FAVALORO A.
Published: December 2007

The dystrophin–glycoprotein complex and the vinculin–talin–integrin system constitute, together a protein machinery, called costameres. The dystrophin–glycoprotein complex contains, among other proteins, also dystrophin and the sarcoglycans subcomplex, proteins playing a key role in the pathogenesis of many muscular dystrophies and linking the cytoplasmic myofibrillar contractile elements to the signal transducing molecules of the extracellular matrix, also providing structural support to the sarcolemma. The vinculin–talin–integrin system connects some components of the extracellular matrix with intermediate filaments of desmin, forming transverse bridges between Z and M lines. In our previous reports we always studied these systems by confocal laser scanning microscopy (CLSM). In this paper we report on the first applications of optical near‐field fluorescence microscopy to the spatial localization of α‐sarcoglycan and β1D‐integrin in human skeletal muscle fibres in order to better compare and test the images obtained with conventional CLSM and with scanning near‐field optical microscopy (SNOM). In addition, the analysis of the surface morphology, and the comparison with the fluorescence map is put forward and analyzed for the first time on human muscle fibres. In aperture‐SNOM the sample is excited through the nanometre‐scale aperture produced at the apex of an optical fibre after tapering and subsequent metal coating. The acquisition of the topography map, simultaneously to the optical signal, by SNOM, permits to exactly overlap the fluorescence images obtained from the two consecutive scans needed for the double localization. Besides, the differences between the topography and the optical spatial patterns permit to assess the absence of artefacts in the fluorescence maps. Although the SNOM represented a good method of analysis, this technique remains a complementary method to the CLSM and it can be accepted in order to confirm the hypothesis advanced by CLSM.
In situ fluorescence microscopy of bacteriophage aggregates
Authors: SERWER PHILIP , HAYES SHIRLEY J. , LIEMAN KAREN , GRIESS GARY A.
Published: December 2007

Virus aggregation is analyzed because of its potential use for both classifying viruses and understanding virus ecology and evolution. Virus aggregation is, however, problematic because aggregation causes loss of virions during processing for microscopy of any type. Thus, here we detect virus aggregation by fluorescence microscopy of wet‐mounted dissections of dilute gel‐supported plaques (in situ fluorescence microscopy) of a test virus, the long‐tail aggregating Bacillus thuringiensis bacteriophage, 0305φ8–36. Background fluorescence is reduced to nonproblematic levels by using the dye, DAPI (4′,6‐diamidino‐2‐phenylindole), to stain viral nucleic acid. In situ fluorescence microscopy reveals two in situ phases, one weakly fluorescent. Most bacteriophages partition to the weakly fluorescent phase. Aggregates of bacteriophage 0305φ8–36 are detected during fluorescence microscopy via the following. (1) Coordinated motion is found for visibly separate particles in solution; the motion is either thermally generated, fluid drift‐induced or mechanical pressure‐induced. (2) Aggregate dissociation is observed. Some of the larger aggregates are elastic and entangled with material of the weakly fluorescent phase. The larger aggregates sometimes sink at 1‐g within specimens. In situ fluorescence microscopy rapidly distinguishes 0305φ8–36 from nonaggregating bacteriophages.
Software image alignment for X‐ray microtomography with submicrometre resolution using a SEM‐based X‐ray microscope
Authors: MAYO S. , MILLER P. , GAO D. , SHEFFIELD‐PARKER J.
Published: December 2007

Improved X‐ray sources and optics now enable X‐ray imaging resolution down to ∼50 nm for laboratory‐based X‐ray microscopy systems. This offers the potential for submicrometre resolution in tomography; however, achieving this resolution presents challenges due to system stability. We describe the use of software methods to enable submicrometre resolution of approximately 560 nm. This is a very high resolution for a modest laboratory‐based point‐projection X‐ray tomography system. The hardware is based on a scanning electron microscope, and benefits from inline X‐ray phase contrast to improve visibility of fine features. Improving the resolution achievable with the system enables it to be used to address a greater range of samples.
Automated electron tomography with scanning transmission electron microscopy
Authors: FENG JIANGLIN , SOMLYO ANDREW P. , SOMLYO AVRIL V. , SHAO ZHIFENG
Published: December 2007

We report the successful implementation of a fully automated tomographic data collection system in scanning transmission electron microscopy (STEM) mode. Autotracking is carried out by combining mechanical and electronic corrections for specimen movement. Autofocusing is based on contrast difference of a focus series of a small sample area. The focus gradient that exists in normal images due to specimen tilt is effectively removed by using dynamic focusing. An advantage of STEM tomography with dynamic focusing over TEM tomography is its ability to reconstruct large objects with a potentially higher resolution.
Role of Escherichia coli in acute diarrhoea in tribal preschool children of central India
Authors: Anvikar Anupkumar R. , Dolla Chandrakumar , Dutta Shanta , Rao Vikas G. , Gadge Vijay S. , Shukla Gajadhar P. , Rao Savinder , Karforma Chandan
Published: December 2007

Five hundred and eighty preschool children belonging to tribal areas of Madhya Pradesh were followed up daily for the presence of diarrhoea for a period of 1 year. In all, 1236 episodes of diarrhoea were recorded with an average of 2.13 episodes per child per year. Stool samples were collected during 780 episodes. They were cultured to isolate Escherichia coli as well as non‐E. coli enteropathogens. Ten different genes were detected to identify all diarrhoeagenic E. coli using multiplex polymerase chain reaction. Enteroaggregative E. coli was the commonest diarrhoeagenic E. coli and was isolated from 64 children, followed by enteropathogenic E. coli (27), enterotoxigenic E. coli (10) and enterohaemorrhagic E. coli (2). Other enteropathogens detected were bacteria such as Shigella sp, Vibrio cholerae and Salmonella sp, parasites such as Giardia lamblia and Entameba histolytica, and rotavirus. Most of the bacterial pathogens were multi‐drug resistant.

The study shows that diarrhoeagenic E. coli contribute significantly to the burden of acute diarrhoea in tribal preschool children.