bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Slow-Release Fluoride Devices and Casein Phosphopeptide/Amorphous Calcium Phosphate Nanocomplexes on Enamel Remineralization in vitro
Authors: Al-Mullahi A.M. , Toumba K.J.
Published: July 2010

To investigate the remineralization effect of slow-release fluoride glass devices (SFGD), casein phosphopeptide/amorphous calcium phosphate nanocomplexes (CPP-ACP) and SFGD and CPP-ACP together on enamel pH cycling in vitro. Eighty bovine enamel slabs were allocated to each of 4 groups (20/group): SFGD; CPP-ACP; SFGD + CPP-ACP; control. Baseline surface microhardness (SMH; Knoop number) was measured for all slabs which were then subjected to a pH cycling regime for 10 days, and SMH was then remeasured. The pH cycling regime involved immersion 5 times daily (each for 5 min) in demineralization solution with the slabs immersed in artificial saliva between dipping. The treatment for the enamel slabs in the SFGD group involved exposure all the time to 2 SFGD devices per group during the cycling regime. In contrast, slabs in the CPP-ACP group were exposed to CPP-ACP slurry once daily for 30 min after the last demineralization challenge of the day. The slabs in the SFGD + CPP-ACP group received both treatments as the SFGD and CPP-ACP groups. The control group received no treatment during the cycling. There was a statistically significant difference in enamel SMH change among the groups (one-way ANOVA; p < 0.0001). Enamel SMH values in the SFGD, CPP-ACP and SFGD + CPP-ACP groups were all significantly higher than in the control group (Bonferroni; p < 0.0001). There was no significant difference in enamel SMH between the SFGD and CPP-ACP groups (p > 0.05). The use of both SFGD + CPP-ACP showed a non-significant trend for improvement in enamel SMH in comparison to SFGD or CPP-ACP alone.
Data reduction for spectral clustering to analyze high throughput flow cytometry data
Authors: Zare Habil , Shooshtari Parisa , Gupta Arvind , Brinkman Ryan R
Published: July 2010

Background

Recent biological discoveries have shown that clustering large datasets is essential for better understanding biology in many areas. Spectral clustering in particular has proven to be a powerful tool amenable for many applications. However, it cannot be directly applied to large datasets due to time and memory limitations. To address this issue, we have modified spectral clustering by adding an information preserving sampling procedure and applying a post-processing stage. We call this entire algorithm SamSPECTRAL.

Results

We tested our algorithm on flow cytometry data as an example of large, multidimensional data containing potentially hundreds of thousands of data points (i.e., "events" in flow cytometry, typically corresponding to cells). Compared to two state of the art model-based flow cytometry clustering methods, SamSPECTRAL demonstrates significant advantages in proper identification of populations with non-elliptical shapes, low density populations close to dense ones, minor subpopulations of a major population and rare populations.

Conclusions

This work is the first successful attempt to apply spectral methodology on flow cytometry data. An implementation of our algorithm as an R package is freely available through BioConductor.
The C. elegans Hox gene ceh-13 regulates cell migration and fusion in a non-colinear way. Implications for the early evolution of Hoxclusters
Authors: Tihanyi Borbála , Vellai Tibor , Regős Ágnes , Ari Eszter , Müller Fritz , Takács-Vellai Krisztina
Published: July 2010

Background

Hox genes play a central role in axial patterning during animal development. They are clustered in the genome and specify cell fate in sequential domains along the anteroposterior (A-P) body axis in a conserved order that is co-linear with their relative genomic position. In the soil worm Caenorhabditis elegans, this striking rule of co-linearity is broken by the anterior Hox gene ceh-13, which is located between the two middle Hox paralogs, lin-39 and mab-5, within the loosely organized nematode Hox cluster. Despite its evolutionary and developmental significance, the functional consequence of this unusual genomic organization remains unresolved.

Results

In this study we have investigated the role of ceh-13 in different developmental processes, and found that its expression and function are not restricted to the anterior body part. We show that ceh-13 affects cell migration and fusion as well as tissue patterning in the middle and posterior body regions too. These data reveal novel roles for ceh-13 in developmental processes known to be under the control of middle Hox paralogs. Consistently, enhanced activity of lin-39 and mab-5 can suppress developmental arrest and morphologic malformation in ceh-13 deficient animals.

Conclusion

Our findings presented here show that, unlike other Hox genes in C. elegans which display region-specific accumulation and function along the A-P axis, the expression and functional domain of the anterior Hox paralog ceh-13 extends beyond the anterior region of the worm. Furthermore, ceh-13 and the middle Hox paralogs share several developmental functions. Together, these results suggest the emergence of the middle-group Hox genes from a ceh-13-like primordial Hox ancestor.
KeaA, a Dictyostelium kelch-domain protein that regulates the response to stress and development
Authors: Mantzouranis Luciana , Bagattini Raquel , Souza Glaucia M
Published: July 2010

Background

The protein kinase YakA is responsible for the growth arrest and induction of developmental processes that occur upon starvation of Dictyostelium cells. yakA

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cells are aggregation deficient, have a faster cell cycle and are hypersensitive to oxidative and nitrosoative stress. With the aim of isolating members of the YakA pathway, suppressors of the death induced by nitrosoative stress in the yakA

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cells were identified. One of the suppressor mutations occurred in keaA, a gene identical to DG1106 and similar to Keap1 from mice and the Kelch protein from Drosophila, among others that contain Kelch domains.

Results

A mutation in keaA suppresses the hypersensitivity to oxidative and nitrosoative stresses but not the faster growth phenotype of yakA

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cells. The growth profile of keaA deficient cells indicates that this gene is necessary for growth. keaA deficient cells are more resistant to nitrosoative and oxidative stress and keaA is necessary for the production and detection of cAMP. A morphological analysis of keaA deficient cells during multicellular development indicated that, although the mutant is not absolutely deficient in aggregation, cells do not efficiently participate in the process. Gene expression analysis using cDNA microarrays of wild-type and keaA deficient cells indicated a role for KeaA in the regulation of the cell cycle and pre-starvation responses.

Conclusions

KeaA is required for cAMP signaling following stress. Our studies indicate a role for kelch proteins in the signaling that regulates the cell cycle and development in response to changes in the environmental conditions.
Prevalence, estimated HIV-1 incidence and viral diversity among people seeking voluntary counseling and testing services in Rio de Janeiro, Brazil
Authors: de Castro Carlos A Velasco , Grinsztejn Beatriz , Veloso Valdiléa G , Bastos Francisco I , Pilotto José H , Morgado Mariza G
Published: July 2010

Background

BED-EIA HIV-1 Incidence Test (BED-CEIA) has been described as a tool to discriminate recent (RS) from long-term (LTS) seroconversion of HIV-1 infection, contributing to a better understanding of the dynamics of the HIV/AIDS epidemic over time. This study determined the prevalence, estimated incidence and HIV-1 subtype infection among individuals seeking testing in Voluntary Counseling and Testing centers (VCTs) from Rio de Janeiro, Brazil.

Methods

Demographics and behavioral data were obtained from 434 individuals, diagnosed as HIV-positive among 9,008 volunteers screened from November 2004 to October 2005 in three VCTs located in the Rio de Janeiro Metropolitan area, Brazil. BED-CEIA protocol was performed to identify RS. DNA samples from RS and a subset of LTS (under a proportion of 1:2) were selected for gp120 C2-V3 and pol (protease and reverse transcriptase) regions genomic sequencing.

Results

Overall HIV-1 prevalence was 4.8%. Sixty-one of 434 seropositive individuals were classified as RS, corresponding to an incidence rate of 1.68%/year (95%CI 1.26% -2.10%). Estimated incidence between Men Who Have Sex with Men (MSM) was 11 times higher than among heterosexual men and 55% of the new cases were identified in volunteers aged 25-40 years. A similar distribution of different HIV-1 subtypes was found among RS and LTS.

Conclusions

Our data suggest that prevention for MSM remains a challenge and efforts focusing on prevention targeting this population should be prioritized. No significant changes in HIV-1 subtypes were observed among the RS and LTS subgroups. One case of HIV-1 AUK (pol)/A (env) recombinant genome was detected for the first time in Brazil.
Plasma folate levels are associated with the lipoprotein profile: a retrospective database analysis
Authors: Semmler Alexander , Moskau Susanna , Grigull Andreas , Farmand Susan , Klockgether Thomas , Smulders Yvo , Blom Henk , Zur Bernd , Stoffel-Wagner Birgit , Linnebank Michael
Published: July 2010

Background

Several studies demonstrated an association of homocysteine plasma levels and the plasma lipoprotein profile. This cross-sectional pilot study aimed at analyzing whether blood levels of the two important cofactors of homocysteine metabolism, folate and vitamin B12, coincide with the lipoprotein profile.

Methods

In a retrospective single center approach, we analyzed the laboratory database (2003-2006) of the University Hospital Bonn, Germany, including 1743 individuals, in whom vitamin B12, folate and at least one lipoprotein parameter had been determined by linear multilogistic regression.

Results

Higher folate serum levels were associated with lower serum levels of low density lipoprotein cholesterol (LDL-C; Beta = -0.164; p < 0.001), higher levels of high density lipoprotein cholesterol (HDL-C; Beta = 0.094; p = 0.021 for trend) and a lower LDL-C-C/HDL-C-ratio (Beta = -0.210; p < 0.001). Using ANOVA, we additionally compared the individuals of the highest with those of the lowest quartile of folate. Individuals of the highest folate quartile had higher levels of HDL-C (1.42 ± 0.44 mmol/l vs. 1.26 ± 0.47 mmol/l; p = 0.005), lower levels of LDL-C (3.21 ± 1.04 mmol/l vs. 3.67 ± 1.10 mmol/l; p = 0.001) and a lower LDL-C/HDL-C- ratio (2.47 ± 1.18 vs. 3.77 ± 5.29; p = 0.002). Vitamin B12 was not associated with the lipoprotein profile.

Conclusion

In our study sample, high folate levels were associated with a favorable lipoprotein profile. A reconfirmation of these results in a different study population with a well defined status of health, diet and medication is warranted.
Transcriptome analysis of human cancer reveals a functional role of Heme Oxygenase-1 in tumor cell adhesion
Authors: Tauber Stefanie , Jais Alexander , Jeitler Markus , Haider Sandra , Husa Julia , Lindroos Josefine , Knöfler Martin , Mayerhofer Matthias , Pehamberger Hubert , Wagner Oswald , Bilban Martin
Published: July 2010

Background

Heme Oxygenase-1 (HO-1) is expressed in many cancers and promotes growth and survival of neoplastic cells. Recently, HO-1 has been implicated in tumor cell invasion and metastasis. However, the molecular mechanisms underlying these biologic effects of HO-1 remain largely unknown. To identify a common mechanism of action of HO-1 in cancer, we determined the global effect of HO-1 on the transcriptome of multiple tumor entities and identified a universal HO-1-associated gene expression signature.

Results

Genome-wide expression profiling of Heme Oxygenase-1 expressing versus HO-1 silenced BeWo choriocarcinoma cells as well as a comparative meta-profiling of the preexisting expression database of 190 human tumors of 14 independent cancer types led to the identification of 14 genes, the expression of which correlated strongly and universally with that of HO-1 (P = 0.00002). These genes included regulators of cell plasticity and extracellular matrix (ECM) remodeling (MMP2, ADAM8, TGFB1, BGN, COL21A1, PXDN), signaling (CRIP2, MICB), amino acid transport and glycosylation (SLC7A1 and ST3GAL2), estrogen and phospholipid biosynthesis (AGPAT2 and HSD17B1), protein stabilization (IFI30), and phosphorylation (ALPPL2). We selected PXDN, an adhesion molecule involved in ECM formation, for further analysis and functional characterization. Immunofluorescence and Western blotting confirmed the positive correlation of expression of PXDN and HO-1 in BeWo cancer cells as well as co-localization of these two proteins in invasive extravillous trophoblast cells. Modulation of HO-1 expression in both loss-of and gain-of function cell models (BeWo and 607B melanoma cells, respectively) demonstrated a direct relationship of HO-1 expression with cell adhesion to Fibronectin and Laminin coated wells. The adhesion-promoting effects of HO-1 were dependent on PXDN expression, as loss of PXDN in HO-1 expressing BeWo and 607B cells led to reduced cell attachment to Laminin and Fibronectin coated wells.

Conclusions

Collectively, our results show that HO-1 expression determines a distinct 'molecular signature' in cancer cells, which is enriched in genes associated with tumorigenesis. The protein network downstream of HO-1 modulates adhesion, signaling, transport, and other critical cellular functions of neoplastic cells and thus promotes tumor cell growth and dissemination.
Glycyrrhizic acid improved lipoprotein lipase expression, insulin sensitivity, serum lipid and lipid deposition in high-fat diet-induced obese rats
Authors: Eu Chia Hui Apphia , Lim Wai Yen Alfred , Ton So Ha , Kadir Khalid bin Abdul
Published: July 2010

Background

The metabolic syndrome, known also as the insulin resistance syndrome, refers to the clustering of several risk factors for atherosclerotic cardiovascular disease. Dyslipidaemia is a hallmark of the syndrome and is associated with a whole body reduction in the activity of lipoprotein lipase (LPL), an enzyme under the regulation of the class of nuclear receptors known as peroxisome proliferator-activated receptor (PPAR). Glycyrrhizic acid (GA), a triterpenoid saponin, is the primary bioactive constituent of the roots of the shrub Glycyrrhiza glabra. Studies have indicated that triterpenoids could act as PPAR agonists and GA is therefore postulated to restore LPL expression in the insulin resistant state.

Results

Oral administration of 100 mg/kg of GA to high-fat diet-induced obese rats for 28 days led to significant reduction in blood glucose concentration and improvement in insulin sensitivity as indicated by the homeostasis model assessment of insulin resistance (HOMA-IR) (p < 0.05). LPL expression was up-regulated in the kidney, heart, quadriceps femoris, abdominal muscle and the visceral and subcutaneous adipose tissues but down-regulated in the liver - a condition in reverse to that seen in high-fat diet-induced obese rats without GA. With regard to lipid metabolism, GA administration led to significant hypotriglyceridemic and HDL-raising effects (p < 0.05), with a consistent reduction in serum free fatty acid, total cholesterol and LDL cholesterol and significant decrease in tissue lipid deposition across all studied tissue (p < 0.01).

Conclusion

In conclusion, GA may be a potential compound in improving dyslipidaemia by selectively inducing LPL expression in non-hepatic tissues. Such up-regulation was accompanied by a GA-mediated improvement in insulin sensitivity, which may be associated with a decrease in tissue lipid deposition. The HDL-raising effect of GA suggests the antiatherosclerotic properties of GA.
Problems in the reporting of acne clinical trials: a spot check from the 2009 Annual Evidence Update on Acne Vulgaris
Authors: Ingram John R , Grindlay Douglas JC , Williams Hywel C
Published: July 2010

In the course of producing the 2009 NHS Evidence - skin disorders Annual Evidence Update on Acne Vulgaris, 25 randomised controlled trials were examined. From these, at least 12 potentially serious problems of trial reporting were identified. Several trials concluded no effect of a treatment yet they were insufficiently powered to exclude potentially useful benefits. There were examples of duplicate publication and "salami publication", as well as two trials being combined and reported as one. In some cases, an incorrect "within-groups" statistical comparison was made and one trial report omitted original efficacy data and included only P values. Both of the non-inferiority studies examined failed to pre-specify a non-inferiority margin. Trials reported as "double-blind" compared treatments that were dissimilar in appearance or had differing adverse effect profiles. In one case an intention-to-treat analysis was not performed and there was a failure to account for all of the randomized participants. Trial results were made to sound more impressive by selective outcome reporting, emphasizing the statistical significance of treatment effects that were clinically insignificant, and by the use of larger-sounding odds ratios rather than rate ratios for common events. Most of the reporting problems could have been avoided by use of the CONSORT guidelines and prospective trial registration on a public clinical trials database.
Imaging Brain Activation
Authors: Dienel Gerald A. , Cruz Nancy F.
Published: July 2010

Elucidation of biochemical, physiological, and cellular contributions to metabolic images of brain is important for interpretation of images of brain activation and disease. Discordant brain images obtained with [14C]deoxyglucose and [1‐ or 6‐14C]glucose were previously ascribed to increased glycolysis and rapid [14C]lactate release from tissue, but direct proof of [14C]lactate release from activated brain structures is lacking. Analysis of factors contributing to images of focal metabolic activity evoked by monotonic acoustic stimulation of conscious rats reveals that labeled metabolites of [1‐ or 6‐14C]glucose are quickly released from activated cells as a result of decarboxylation reactions, spreading via gap junctions, and efflux via lactate transporters. Label release from activated tissue accounts for most of the additional [14C]glucose consumed during activation compared to rest. Metabolism of [3,4‐14C]glucose generates about four times more [14C]lactate compared to 14CO2 in extracellular fluid, suggesting that most lactate is not locally oxidized. In brain slices, direct assays of lactate uptake from extracellular fluid demonstrate that astrocytes have faster influx and higher transport capacity than neurons. Also, lactate transfer from a single astrocyte to other gap junction‐coupled astrocytes exceeds astrocyte‐to‐neuron lactate shuttling. Astrocytes and neurons have excess capacities for glycolysis, and oxidative metabolism in both cell types rises during sensory stimulation. The energetics of brain activation is quite complex, and the proportion of glucose consumed by astrocytes and neurons, lactate generation by either cell type, and the contributions of both cell types to brain images during brain activation are likely to vary with the stimulus paradigm and activated pathways.
Screening for the Metabolic Basis of Neurodegeneration
Authors: Murray James , Capaldi Roderick A.
Published: July 2010

Metabolism is controlled by a complex system of transcriptional events and posttranslational modifications stimulated by substrate and metabolite availability. It is becoming clear that neurodegenerative diseases are a symptom of a deficiency in the regulation or execution of metabolic reactions. Mitochondria, as the central organelles in metabolic regulation as well as the chief generators of reactive species, clearly have a role to play in the etiology of neurodegenerative conditions. We are developing antibody‐based capture arrays to determine multiple parameters of key mitochondrial proteins. Parameters include enzyme activity, quantity, oxidative modification (including nitrative and oxidative stress), and regulation (phosphorylation and acetylation). At this time the core of this array focuses on the enzymes of oxidative phosphorylation. We continue to expand this array as antibodies for enzyme isolation and modification detection become available. Here we demonstrate the use of this array by analyzing the proteomic differences in oxidative phosphorylation enzymes between human heart and liver tissues, cells grown in media promoting aerobic versus anaerobic metabolism, and the catalytic/proteomic effects of mitochondria exposed to oxidative stress.
Multinuclear Magnetic Resonance Spectroscopy for in Vivo Assessment of Mitochondrial Dysfunction in Parkinson's Disease
Authors: Henchcliffe Claire , Shungu Dikoma C. , Mao Xiangling , Huang Chaorui , Nirenberg Melissa J. , Jenkins Bruce G. , Beal M. Flint
Published: July 2010

Parkinson's disease (PD) is a common and often devastating neurodegenerative disease affecting up to one million individuals in the United States alone. Multiple lines of evidence support mitochondrial dysfunction as a primary or secondary event in PD pathogenesis; a better understanding, therefore, of how mitochondrial function is altered in vivo in brain tissue in PD is a critical step toward developing potential PD biomarkers. In vivo study of mitochondrial metabolism in human subjects has previously been technically challenging. However, proton and phosphorus magnetic resonance spectroscopy (1H and 31P MRS) are powerful noninvasive techniques that allow evaluation in vivo of lactate, a marker of anaerobic glycolysis, and high energy phosphates, such as adenosine triphosphate and phosphocreatine, directly reflecting mitochondrial function. This article reviews previous 1H and 31P MRS studies in PD, which demonstrate metabolic abnormalities consistent with mitochondrial dysfunction, and then presents recent 1H MRS data revealing abnormally elevated lactate levels in PD subjects.
The same enhancer regulates the earliestEmx2expression in caudal forebrain primordium, subsequent expression in dorsal telencephalon and later expression in the cortical ventricular zone
Authors: Suda Yoko , Kokura Kenji , Kimura Jun , Kajikawa Eriko , Inoue Fumitaka , Aizawa Shinichi
Published: July 2010

We have analyzed Emx2 enhancers to determine how Emx2 functions during forebrain development are regulated. The FB (forebrain) enhancer we identified immediately 3′ downstream of the last coding exon is well conserved among tetrapods and unexpectedly directed all the Emx2 expression in forebrain: caudal forebrain primordium at E8.5, dorsal telencephalon at E9.5-E10.5 and the cortical ventricular zone after E12.5. Otx, Tcf, Smad and two unknown transcription factor binding sites were essential to all these activities. The mutant that lacked this enhancer demonstrated that Emx2 expression under the enhancer is solely responsible for diencephalon development. However, in telencephalon, the FB enhancer did not have activities in cortical hem or Cajal-Retzius cells, nor was its activity in the cortex graded. Emx2 expression was greatly reduced, but persisted in the telencephalon of the enhancer mutant, indicating that there exists another enhancer for Emx2 expression unique to mammalian telencephalon.
Transcriptomic landscape of the primitive streak
Authors: Alev Cantas , Wu Yuping , Kasukawa Takeya , Jakt Lars M. , Ueda Hiroki R. , Sheng Guojun
Published: July 2010

In birds and mammals, all mesoderm cells are generated from the primitive streak. Nascent mesoderm cells contain unique dorsoventral (D/V) identities according to their relative ingression position along the streak. Molecular mechanisms controlling this initial phase of mesoderm diversification are not well understood. Using the chick model, we generated high-quality transcriptomic datasets of different streak regions and analyzed their molecular heterogeneity. Fifteen percent of expressed genes exhibit differential expression levels, as represented by two major groups (dorsal to ventral and ventral to dorsal). A complete set of transcription factors and many novel genes with strong and region-specific expression were uncovered. Core components of BMP, Wnt and FGF pathways showed little regional difference, whereas their positive and negative regulators exhibited both dorsal-to-ventral and ventral-to-dorsal gradients, suggesting that robust D/V positional information is generated by fine-tuned regulation of key signaling pathways at multiple levels. Overall, our study provides a comprehensive molecular resource for understanding mesoderm diversification in vivo and targeted mesoderm lineage differentiation in vitro.
Estimating the Effect of Unearned Income on Labor Earnings, Savings, and Consumption: Evidence from a Survey of Lottery Players
Authors: Imbens Guido W , Rubin Donald B , Sacerdote Bruce I
Published: July 2010

This paper provides empirical evidence about the effect of unearned income on earnings, consumption, and savings. Using an original survey of people playing the lottery in Massachusetts in the mid-1980's, we analyze the effects of the magnitude of lottery prizes on economic behavior. The critical assumption is that among lottery winners the magnitude of the prize is randomly assigned. We find that unearned income reduces labor earnings, with a marginal propensity to consume leisure of approximately 11 percent, with larger effects for individuals between 55 and 65 years old. After receiving about half their prize, individuals saved about 16 percent. (JEL C81, D12, E21, J22, J26)
What Accounts for the Variation in Retirement Wealth Among U.S. Households?
Authors: Bernheim B. Douglas , Skinner Jonathan , Weinberg Steven
Published: July 2010

Even among households with similar socioeconomic characteristics, saving and wealth vary considerably. Life-cycle models attribute this variation to differences in time preference rates, risk tolerance, exposure to uncertainty, relative tastes for work and leisure at advanced ages, and income replacement rates. These factors have testable implications concerning the relation between accumulated wealth and the shape of the consumption profile. Using the Panel Study of Income Dynamics and the Consumer Expenditure Survey, we find little support for these implications. The data are instead consistent with “rule of thumb,” “mental accounting,” or hyperbolic discounting theories of wealth accumulation. (JEL D1, D91, E21)
The Stock Market and Capital Accumulation
Authors: Hall Robert E
Published: July 2010

The value of a firm's securities measures the value of the firm's productive assets. If the assets include only capital goods and not a permanent monopoly franchise, the value of the securities measures the value of the capital. Finally, if the price of the capital can be measured or inferred, the quantity of capital is the value divided by the price. A standard model of adjustment costs enables the inference of the price of installed capital. Data from U.S. corporations over the past 50 years imply that corporations have formed large amounts of intangible capital, especially in the past decade. (JEL E44, G12)
Is the Price Level Determined by the Needs of Fiscal Solvency?
Authors: Canzoneri Matthew B , Cumby Robert E , Diba Behzad T
Published: July 2010

The fiscal theory of price determination suggests that if primary surpluses evolve independently of government debt, the equilibrium price level “jumps” to assure fiscal solvency. In this non-Ricardian regime, fiscal policy—not monetary policy—provides the nominal anchor. Alternatively, in a Ricardian regime, primary surpluses are expected to respond to debt in a way that assures fiscal solvency, and the price level is determined in conventional ways. This paper argues that Ricardian regimes are as theoretically plausible as non-Ricardian regimes, and provide a more plausible interpretation of certain aspects of the postwar U.S. data than do non-Ricardian regimes. (JEL E60, E63)
Why Regulate Insider Trading? Evidence from the First Great Merger Wave (1897–1903)
Authors: Banerjee Ajeyo , Eckard E. Woodrow
Published: July 2010

We use event-time methodology to study legal insider trading associated with mergers circa 1900. For mergers with “prospective” disclosures similar to today's, we find substantial value gains at announcement, implying participation by “out-side” shareholders despite the absence of insider constraints. Furthermore, preannouncement stock-price runups, relative to total value gain, are no more than those observed for modern mergers. Insider regulation apparently has produced little benefit for outsiders, with the inside information-pricing function and related gains shifting to external “information specialists.” Other results suggest market penalties for nondisclosure; i.e., insider trading is less successful in a restricted information environment. (JEL G3, K2, L5, N2)
Investigation on wax-impregnated wood. Part 1: Microscopic observations and 2D X-ray imaging of distinct wax types
Authors: Scholz Gunthard , Van den Bulcke Jan , Boone Matthieu , Zauer Mario , Bäucker Ernst , Van Acker Joris , Militz Holger
Published: July 2010

The migration and deposition of hot melting wax in wax-treated wood is not described in detail in the literature, although such products are available on the market. In the present study, this topic was investigated based on pine sapwood (Pinus sylvestris L.) and beech (Fagus sylvatica L.). The behavior of three different waxes was studied by means of 2D X-ray measurements and scanning electron microscopy observations. The three waxes did not show distinct differences in their deposition patterns. An intensive wax deposition could be observed within the vessels, tracheids, and fibers. In P. sylvestris the ray tracheids were penetrated with hot melting waxes, therefore there is a lateral wood penetration from the outer to the inner wood. In general, no wax penetration was visible within the parenchyma tissue and epithelium cells. Cracks were detected within the wax deposits as well as secondary microcapillaries, which were visible between the deposits and the cell walls.
A CP/MAS 13C-NMR study of cellulose fibril aggregation in eucalyptus dissolving pulps during drying and the correlation between aggregate dimensions and chemical reactivity
Authors: Chunilall Viren , Bush Tamara , Larsson Per Tomas , Iversen Tommy , Kindness Andrew
Published: July 2010

Changes in supramolecular properties of cellulose I, namely its lateral fibril aggregate dimension (LFAD), in bleached hardwood acid bisulphite pulp during drying was studied using cross-polarization/magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C-NMR) in combination with spectral fitting. A significant change in aggregate dimensions was noticed when each of the pulp grades were oven dried. The effect of drying was further investigated with pulp samples subjected to different drying methods. A comparison of a harsh oven drying, mild and rapid air drying, and a very mild and slow condition drying showed that the LFAD of the material decreases in the following order: oven drying > air drying > condition drying. The correlation between the total extractable material S10 (%) and LFAD and also the LFAD increment (ΔLFAD in %) are presented and shown to be intimately related. This means that the method of drying influences the size of the fibril aggregate dimensions and depends on the presence of extractable material within the fibre cell wall. Reactivity studies were carried out based on the acetylation of cotton linters and commercial 96α pulp. Results indicate that the initial reaction rate is proportional to the specific surface area of the two cellulose pulp samples. Accordingly, the specific surface area is directly related to initial reactivity of the performed acetylation. We demonstrated that it is possible to control the LFAD and hence specific surface area in laboratory-produced pulps 91α, 92α, and 96α by the drying method. Thus controlling LFAD can probably be one viable route for controlling the initial reactivity of dissolving pulp towards acetylation.
REFLET Experiment in OSIRIS: Relaxation under Flux as a Method for Determining Creep Behavior of Zircaloy Assembly Components
Authors: Carassou S. , Duguay C. , Yvon P. , Rozenblum F. , Cloué J. M. , Chabretou V. , Bernaudat C. , Levasseur B. , Maurice A. , Bouffioux P. , Audic K.
Published: July 2010

A stress relaxation on bent-beam specimen irradiation campaign was performed in the French material testing reactor OSIRIS in order to screen different materials according to their in-flux behavior and to derive constitutive laws that are used to describe the in-reactor behavior of assembly components under axial stress. This paper presents the methodology used, with particular emphasis on the validation of the different hypotheses. The methodology is illustrated with the results obtained on an industrial Zircaloy-4 (Zy-4) alloy used in guide thimbles. As an illustration of the capability of the method, the parameters of simple creep behavior laws are adjusted to the relaxation results. The creep-law predictions are compared to results obtained previously in a creep experiment.
Persistence of Coordinated Long-Term Potentiation and Dendritic Spine Enlargement at Mature Hippocampal CA1 Synapses Requires N-Cadherin
Authors: Bozdagi Ozlem , Wang Xiao-bin , Nikitczuk Jessica S. , Anderson Tonya R. , Bloss Erik B. , Radice Glenn L. , Zhou Qiang , Benson Deanna L. , Huntley George W.
Published: July 2010

Persistent changes in spine shape are coupled to long-lasting synaptic plasticity in hippocampus. The molecules that coordinate such persistent structural and functional plasticity are unknown. Here, we generated mice in which the cell adhesion molecule N-cadherin was conditionally ablated from postnatal, excitatory synapses in hippocampus. We applied to adult mice of either sex a combination of whole-cell recording, two-photon microscopy, and spine morphometric analysis to show that postnatal ablation of N-cadherin has profound effects on the stability of coordinated spine enlargement and long-term potentiation (LTP) at mature CA1 synapses, with no effects on baseline spine density or morphology, baseline properties of synaptic neurotransmission, or long-term depression. Thus, N-cadherin couples persistent spine structural modifications with long-lasting synaptic functional modifications associated selectively with LTP, revealing unexpectedly distinct roles at mature synapses in comparison with earlier, broader functions in synapse and spine development.
Cannabinoids Excite Circadian Clock Neurons
Authors: Acuna-Goycolea Claudio , Obrietan Karl , van den Pol Anthony N.
Published: July 2010

Cannabinoids, the primary active agent in drugs of abuse such as marijuana and hashish, tend to generate a distorted sense of time. Here we study the effect of cannabinoids on the brain's circadian clock, the suprachiasmatic nucleus (SCN), using patch clamp and cell-attached electrophysiological recordings, RT-PCR, immunocytochemistry, and behavioral analysis. The SCN showed strong expression of the cannabinoid receptor CB1R, as detected with RT-PCR. SCN neurons, including those using GABA as a transmitter, and axons within the SCN, expressed CB1R immunoreactivity. Behaviorally, cannabinoids did not alter the endogenous free-running circadian rhythm in the mouse brain, but did attenuate the ability of the circadian clock to entrain to light zeitgebers. In the absence of light, infusion of the CB1R antagonist AM251 caused a modest phase shift, suggesting endocannabinoid modulation of clock timing. Interestingly, cannabinoids had no effect on glutamate release from the retinohypothalamic projection, suggesting a direct action of cannabinoids on the retinohypothalamic tract was unlikely to explain the inhibition of the phase shift. Within the SCN, cannabinoids were excitatory by a mechanism based on presynaptic CB1R attenuation of axonal GABA release. These data raise the possibility that the time dissociation described by cannabinoid users may result in part from altered circadian clock function and/or entrainment to environmental time cues.
Ric-3 Promotes α7 Nicotinic Receptor Assembly and Trafficking through the ER Subcompartment of Dendrites
Authors: Alexander John K. , Sagher Daphna , Krivoshein Arcadius V. , Criado Manuel , Jefford Gregory , Green William N.
Published: July 2010

The function of Ric-3, which is required for nicotinic acetylcholine receptor (nAChR) expression inC. elegans, is unclear. Here we found that Ric-3 can promote or inhibit cell-surface delivery of α-bungarotoxin-binding nAChRs (BgtRs) composed of α7 subunits. At low levels, Ric-3 promoted BgtR assembly, endoplasmic reticulum (ER) release, and cell-surface delivery without trafficking from the ER. At high Ric-3 levels, Ric-3 suppressed BgtR surface delivery, but not its assembly, and BgtRs were retained in the ER or in Ric-3-containing aggregates. In PC12 cells, native BgtRs trafficked to the cell surface from the ER where low levels of endogenous Ric-3 were observed. In cultured neurons, native Ric-3 levels were higher than in PC12 cells, and Ric-3 and α7 subunits were found in somata and dendrites, but not axons, of inhibitory interneurons. Ric-3 trafficked with α7 subunits in rapidly moving vesicles to dendrites, where it was restricted to the ER subcompartment. We conclude that Ric-3 has two potential functions. At low levels, Ric-3 interactions are short-lived and promote BgtR assembly and ER release. At higher levels, Ric-3 interactions are longer-lived and mediate ER retention. In neurons, Ric-3 ER retention appears to promote transport within the dendritic ER subcompartment, thereby restricting α7 trafficking to dendrites and preventing axonal transport.
Frequência de Bacillus spp. em solos de diferentes sistemas de cultivo de arroz irrigado em Cachoeirinha, RS
Authors: Fritz Leila Lucia , Berlitz Diouneia Lisiane , Macedo Vera Regina Mussoi , Machado Vilmar , Fiuza Lidia Mariana
Published: July 2010

Bacilos entomopatogênicos são bactérias observadas principalmente no solo, consideradas importantes agentes no controle biológico de doenças e pragas da agricultura. No entanto, existem poucos estudos que relatam a influência das práticas agrícolas nas populações de Bacillus spp. Essa pesquisa objetivou avaliar a freqüência de bactérias entomopatogênicas pertencentes ao gênero Bacillus obtidas de amostras de solo coletadas no ano agrícola de 2006/2007 de diferentes sistemas de cultivo de arroz irrigado da EEA-IRGA, Cachoeirinha (RS). Foram analisadas 36 amostras de solos, oriundas de três sistemas de plantio de arroz irrigado, pré-germinado (SPG), convencional (SPC), plantio direto (SPD) e de uma área sem plantio de arroz (C). Para tanto, um grama de solo foi diluído, pasteurizado e inoculado em Ágar Nutriente (AN), incubado a 30 °C, por 24 horas. Todas as unidades formadoras de colônias bacterianas (UFC) foram repicadas em meios seletivos e as espécies, B. thuringiensis, B. sphaericus e B. cereus, foram identificadas por microscopia de contraste de fase. Os resultados revelaram que não houve diferença significativa entre os sistemas de plantio analisados. Por outro lado, a frequência de Bacillus spp. variou entre as diferentes fases do plantio de arroz nos períodos amostrados. A irrigação foi o principal fator que contribuiu para a variação da frequência dos Bacillus em sistemas de plantio de arroz irrigado da EEA-IRGA.
Variabilidade espacial de atributos físicos de um argissolo vermelho-amarelo cultivado com leguminosas consorciada com a seringueira
Authors: Vieira Sidney Rosa , Brancalião Sandro Roberto , Grego Célia Regina , Martins Antonio Lúcio Mello
Published: July 2010

O objetivo deste trabalho foi avaliar a distribuição espacial de alguns atributos físicos do solo e verificar suas alterações no desenvolvimento da seringueira consorciada com leguminosas. O experimento foi instalado em Argissolo Vermelho-Amarelo no Polo Regional de Desenvolvimento Tecnológico dos Agronegócios do Centro-Norte, localizado em Pindorama (SP). Foram avaliadas: infiltração de água a 0,10 e a 0,20 m de profundidade, macro e micro porosidade e densidade do solo nas camadas 0-0,10; 0,10-0,20; 0,20-0,40 e 0,40-0,60 m. O desenvolvimento das plantas de seringueira foi avaliado medindo-se o perímetro do caule e o aumento desta medida no período de quatro anos (1996-1999). Os dados foram submetidos à análise de estatística descritiva para verificação de parâmetros de tendência central e dispersão. Foram utilizados métodos geoestatísticos incluindo semivariogramas, krigagem e mapas de isolinhas para a avaliação da variabilidade espacial. Houve dependência espacial de moderada a forte para todos os atributos do solo, com o valor do alcance variando entre 15 e 90 m. A dependência espacial anotada para infiltração de água no solo não teve relação com as avaliações efetuadas nas plantas nem com os outros atributos avaliados. Os altos valores de densidade do solo e de microporosidade na camada de 0,20-0,40 m indicaram a ocorrência de compactação nesta camada. O perímetro do caule de seringueira aumentou linearmente com o tempo, porém a taxa de crescimento do perímetro do caule decresceu ao longo dos anos. A taxa média de crescimento do perímetro do caule variou em função do crescimento menor no inverno quando comparado com o do verão. Na distribuição espacial do espessamento do caule das árvores de seringueira ao longo do tempo houve alta continuidade, avaliada pelos baixos valores do efeito pepita dos semivariogramas e estreita correlação com densidade do solo, onde locais menos densos tiveram os maiores valores para o perímetro do caule da seringueira.
Morcegos da região sul do Brasil: análise comparativa da riqueza de espécies, novos registros e atualizações nomenclaturais (Mammalia, Chiroptera)
Authors: Passos Fernando C. , Miranda João M. D. , Bernardi Itiberê P. , Kaku-Oliveira Nathalia Y. , Munster Luana C.
Published: July 2010

Uma análise comparativa da riqueza de espécies de morcegos da Região Sul do Brasil é apresentada, assim como análises de similaridades entre estados. O estado do Paraná apresentou a maior riqueza de espécies de morcegos, com 64 espécies, seguido por Santa Catarina com 46 e pelo Rio Grande do Sul com 40. A família Phyllostomidae influencia fortemente este padrão de riqueza. As distribuições geográficas de Trachops cirrhosus (Spix, 1823), Artibeus cinereus (Gervais, 1851) e Thyroptera tricolor Spix, 1823 são ampliadas até o Paraná, estabelecendo um novo limite sul de distribuição dessas espécies e da família Thyropteridae. Além disso, Myotis dinellii Thomas, 1902 foi registrado pela primeira vez no Brasil, em Santa Catarina e no Rio Grande do Sul, estabelecendo um novo limite leste para sua distribuição. Ainda, é ampliada a distribuição de Eptesicus taddeii Miranda, Bernardi & Passos, 2006 a partir de seu primeiro registro no estado do Rio Grande do Sul. Uma lista atualizada dos morcegos dos estados sul-brasileiros é apresentada bem como algumas adequações nomenclaturais. É enfatizada a importância do emprego de maiores esforços de campo para levantamentos da quiropterofauna, que assim podem contribuir para medidas de conservação embasadas em inventariamentos e coleções científicas representativas.
Determination of patulin in apple juice by HPLC using a simple and fast sample preparation method
Authors: Sargenti Silvia R. , Almeida Carlos A. A.
Published: July 2010

The goal of this work was to develop a simple and rapid preparation method for patulin analysis in apple juice without previous clean-up. This method combined sonication and liquid extraction techniques and was used for determination of patulin in 37 commercial apple juices available on the market in the South of Brazil. The method performance characteristics were determined using a sample obtained in a local market fortified at five concentration levels of patulin and done in triplicates. The coefficient of variation for repeatability at the fortification level of 20.70µg.L-1 was 3.53 % and the recovery 94.63 %, respectively. The correlation coefficient was 0.9996 and agrees with the requirements for a linear analytical method value. The detection limit was 0.21µg.L-1 and the quantification limit 0.70 µg.L-1. Only three of the analyzed samples were upper the allowed level of 50.00 µg.L-1 recommended for the World Health Organization.
Detection, transmission, pathogenicity and chemical treatment of fungi in Ceiba speciosa seeds
Authors: Lazarotto Marília , Muniz Marlove Fátima Brião , Santos Álvaro Figueredo dos
Published: July 2010

The aim of this work was to evaluate fungus association, transmission and pathogenicity, besides chemical seed treatment in Ceiba speciosa seeds from different regions of southern Brazil. Seven seed samples were used to do the germination test, fungus detection by blotter test and potato-dextrose-agar (PDA), fungus transmission and pathogenicity tests; besides, chemical seed treatments were tested. Germination ranged from 0 to 59,5%. The following fungi were associated in the seeds: Fusarium sp., Alternaria sp., Colletotrichum sp., Curvularia sp. and Pestalotia sp.; in addition, Fusarium sp. was found in all the samples. Alternaria sp. and Fusarium sp. were transmitted by seeds. The isolates of Alternaria sp., Colletotrichum sp. and Fusarium sp., were pathogenic to seedlings and seeds. The seed treatment with methyl tiophanate and the combination captan + methyl tiophanate reduced Fusarium sp. incidence.
Efeito de indutores bióticos e abióticos na atividade de quitinase e peroxidase e no controle da ferrugem causada por Puccinia psidii em eucalipto
Authors: Boava Leonardo Pires , Kuhn Odair José , Pascholati Sérgio Florentino , Di Piero Robson Marcelo , Furtado Edson Luiz
Published: July 2010

Verificou-se o efeito de indutores de resistência bióticos e abióticos nas atividades de quitinase e peroxidase e na redução da severidade da ferrugem do eucalipto causada por Puccinia psidii. Para isso, mudas de dois clones de eucalipto (Eucalyptus grandis x E. urophylla) denominados VR e C0, com sessenta dias de idade, mantidas em casa de vegetação, receberam tratamentos com Bion® (Acibenzolar-S-metil-ASM), Agro-Mos®, Dipel®, Ecolife40®, Crop-set® e uma preparação obtida a partir de Saccharomyces cerevisiae, 5 dias antes da inoculação com o patógeno. Uma suspensão de uredósporos de P. psidii, coletados a partir de plantas naturalmente infectadas, foi calibrada para 5 x 10(4) uredósporos/ mL. A inoculação foi realizada na face abaxial das folhas e a avaliação se deu 15 dias após, estimando-se a severidade da doença por meio de escala de notas. Os tratamentos ASM, preparado de S. cerevisiae e Ecolife® apresentaram os melhores resultados de controle da doença e os demais tratamentos não se mostraram eficazes para o controle. O aumento de atividade das enzimas quitinase e peroxidase foi observado em ambos os clones, previamente tratados com os indutores(ASM e S. cerevisiae), 48 horas após a inoculação com o fungo.