bluuebunny/crossref_metadata_2025 huggingface dataset:
Correlations Between Amino Acids at Different Sites in Local Sequences of Protein Fragments with Given Structural Patterns
Authors: Lu Wen , Liu Hai-yan
Published: June 2008

Ample evidence suggests that the local structures of peptide fragments in native proteins are to some extent encoded by their local sequences. Detecting such local correlations is important but it is still an open question what would be the most appropriate method. This is partly because conventional sequence analyses treat amino acid preferences at each site of a protein sequence independently, while it is often the inter-site interactions that bring about local sequence-structure correlations. Here a new scheme is introduced to capture the correlation between amino acid preferences at different sites for different local structure types. A library of nine-residue fragments is constructed, and the fragments are divided into clusters based on their local structures. For each local structure cluster or type, chi-square tests are used to identify correlated preferences of amino acid combinations at pairs of sites. A score function is constructed including both the single site amino acid preferences and the dual-site amino acid combination preferences, which can be used to identify whether a sequence fragment would have a strong tendency to form a particular local structure in native proteins. The results show that, given a local structure pattern, dual-site amino acid combinations contain different information from single site amino acid preferences. Representative examples show that many of the statistically identified correlations agree with previously-proposed heuristic rules about local sequence-structure correlations, or are consistent with physical-chemical interactions required to stabilize particular local structures. Results also show that such dual-site correlations in the score function significantly improves the Z-score matching a sequence fragment to its native local structure relative to non-native local structures, and certain local structure types are highly predictable from the local sequence alone if inter-site correlations are considered.
Preparation and Optical Properties of (Nanometer MCM-41)-CdS Composite Materials
Authors: Zhai Qing-zhou , Liu Yue-xiang
Published: June 2008

The nanometer and micrometer molecular sieves MCM-41 were prepared by a hydrothermal method. Cadmium (II) was exchanged into the molecular sieves by ion-exchange, and thioacetamide was then used as a precursor of hydrogen sulfide for sulphidizing the (MCM-41)-cadmium samples to prepare the host-guest composite materials (MCM-41)-CdS. By means of chemical analysis, powder X-ray diffraction, infrared spectroscopy, low temperature nitrogen adsorption-desorption technique, solid state diffuse reflectance absorption spectroscopy and luminescence, the prepared materials were characterized. The chemical analysis shows that the guest is successfully trapped in the molecular sieves. The powder X-ray diffraction suggests that the frameworks of the molecular sieves in the prepared host-guest composite materials are retained during the preparative process. They are intact and the degrees of crystallinity are still very high. The infrared spectra show that the frameworks of the prepared host-guest materials keep intact. The low temperature nitrogen adsorption-desorption studies indicate that the pore volumes, the pore sizes and the surface areas of the prepared composite materials decrease relative to those of the MCM-41 molecular sieve hosts. This shows that the guests are successfully encapsulated in the channels of the molecular sieves. The solid state diffuse reflectance absorption spectra of the prepared host-guest composites show some blue-shifts relative to that of bulk cadmium sulfide, indicating that the guests are trapped in the channels of the molecular sieves. This shows the obvious stereoscopic confinement effect of the molecular sieve host on the nanometer cadmium sulfide guest. The (nanometer MCM-41)-CdS and (micrometer MCM-41)-CdS samples show obvious luminescence.
Raman Spectrum of Er-Y-codoped ZrO2 and Fluorescence Properties of Er3+
Authors: He Jun , Luo Meng-fei , Jin Ling-yun , He Mai , Fang Ping , Xie Yun-long
Published: June 2008

Er-Y-codoped ZrO2 mixed oxides with monoclinic, tetragonal and cubic structures were prepared by a sol-gel method. The crystal structure of ZrO2 matrix and the effect of the ZrO2 phases on the fluorescence properties of Er3+ were studied using Raman spectroscopy. The results indicated that the fluorescence properties of Er3+ depend on its local ZrO2 crystal structures. As ZrO2 matrix transferred from monoclinic to tetragonal and cubic phase, the Raman and fluorescence bands of Er3+ decreased in intensities and tended to form a single peak. With 632.8 nm excitation, the bands between 640 and 680 nm were attributed to the fluorescence of Er3+ in the ZrO2 environment. However, only the fluorescence was observed and no Raman spectra were seen under 514.5 nm excitation, while only Raman spectra were observed under 325 nm excitation. UV Raman spectroscopy was found to be more sensitive in the surface region while the information provided by XRD mainly came from the bulk. The phase with lower symmetry forms more easily on the surface than in the bulk.
Direct Dynamics Simulation of Reaction Between F2 and Ethylene
Authors: Qi Yan , Han Ke-li , Varandas Antonio J. C.
Published: June 2008

Direct dynamics within the framework of DFT was used to study the long-time puzzling mechanism of the reaction between F2 and ethylene. Three types of reactions are widely accepted : F atom elimination reaction, HF elimination reaction and the addition reaction. Several reaction mechanisms have been proposed, but only the radical mechanism can reasonably explain the initial reaction at low temperature. In this article, our calculations support the radical mechanism and the reaction mechanisms of the three reactions, and they are described in detail by trajectory simulation. The reactions in a cryogenic matrix with the reaction mechanism were also discussed.
Theoretical Study of RgNO (Rg=He, Ne, Ar and Kr) Complexes
Authors: Wang Si-sheng , Kong Rui-hong , Sheng Liu-si , Hao Li-qing , Zhou Shi-kang , Wang Zhen-ya
Published: June 2008

RgNO (Rg=He, Ne, Ar and Kr) complexes were studied using ab initio calculations. The neutral RgNO complex geometry and vibrational frequencies were calculated with the cc-pVDZ basis set at the CCSD(T) level of theory. The calculations show that the geometry of the RgNO complexes is a skewed T-shape with the Rg atom on the oxygen side of the NO molecule, and that the RgNO bond angle increases with mass. The dissociation energies (DE) and ionization energies (IE) of the neutral RgNO complexes, and the dissociation energies of RgNO+ ionic complexes were calculated using Gaussian-2 (G2) methods and a high accuracy energy model. The ionization energies of the neutral RgNO complexes range from 9.265 eV for HeNO to 9.132 eV for KrNO and the dissociation energies of RgNO+ range from 0.017 eV for HeNO+ to 0.156 eV for KrNO+, in line with the expectation based on the increasing polarizability of the Rg atom.
Optimal Internal Noise for Mammalian Circadian Oscillator
Authors: Wang Zhi-wei , Hou Zhong-huai , Xin Hou-wen
Published: June 2008

Based on a deterministic mammalian circadian oscillator proposed recently, we have constructed the corresponding mesoscopic stochastic model, and studied the effect of internal noise on the genetic oscillations of such a system. It is found that the stochastic genetic oscillations can show best performance at an optimal internal noise level via a mechanism of internal noise stochastic resonance. Furthermore, it is found that there exists a moderate system size that makes the stochastic model show effective oscillation at more extended region than the deterministic description, which indicates enhanced robustness as the result of internal noise. The potential biological application of such an effect is also discussed.
Radiative Properties of Transparent PLZT Doped with Tm3+ for Active Electro-optical Applications
Authors: Li Bao-zeng , Chen Xue-sheng , Jiang Hua , Zheng Zhi-qiang , Wang An-ting , Ming Hai
Published: June 2008

The optical transition probability of Tm3+ (7.0 mol%) doped PLZT was investigated because of its great interest in many fields such as optical communications in the mid-infrared waveband and medical instrumentation. The absolute intensities of its forced electric dipole transitions between 420 and 2000 nm were measured. According to Judd-Ofelt (J-O) theory, three phenomenological parameters, 2=9.1331021 cm2, 4=1.5291021 cm2 and 6=1.7121021 cm2, were obtained. The J-O intensity parameters were used to calculate the radiative lifetime (7.493 ms) of the excited 3F4 level. The stimulated emission cross-section for the 3F43H6 transition was also evaluated. Analysis reveals that Tm3+-doped PLZT is promising for use as efficient optical amplification devices or zero-loss electro-optical devices.
Theoretical Studies on Stabilities and Spectroscopy of C78O5
Authors: Wu Shi , Teng Qi-wen , Chen Si-cong
Published: June 2008

The semi-empirical AM1 and INDO/CIS methods as well as density function theory were used to study equilibrium geometries and spectroscopic properties of the possible isomers of C78O5 based on C2v-C78. The most stable geometry of C78O5 is 28,29,30,31,52,53,70,71,73,78-C78O5(A) with one annulene-like structure and four epoxide structures. Compared with that of C2v-C78, the blue-shift in the electronic absorption spectra of C78O5 isomers is predicted. The reason for the blue-shift effect is discussed and the electronic transitions are assigned. The IR and NMR spectra of C78O5 are explored with the AM1 and B3LYP/6-31G methods based on the B3LYP/6-31G optimized geometries.
Structure-Activity Relationship of Fluoroquinolones AgainstK. pneumoniae
Authors: Li Xiao-hong , Zhang Rui-zhou , Cheng Xin-lu , Yang Xiang-dong
Published: June 2008

The structure-activity relationship of fluoroquinolones, which show anti-K. pneumoniae activity, was studied by using principal component analysis (PCA) and hierarchical cluster analysis (HCA). The PCA results showed that the lowest unoccupied molecular orbital energy, energy difference between the highest occupied and the lowest unoccupied molecular orbital, dipole moment, net atomic charge on atom I, molecular polarizability, partition coefficient and molecular refractivity of these compounds are responsible for the separation between high-activity and low-activity groups. The HCA results were similar to those obtained with PCA. By using the chemometric results, four synthetic compounds were analyzed through PCA and HCA, and three of them are proposed as active molecules against K. pneumoniae which is consistent with the results of clinical experiments. The methodologies of PCA and HCA provide a reliable rule for classifying new fluoroquinolones with anti-K. pneumoniae activity.
Microstructure of Mixed Cadmium Stearate and Behenate Langmuir-Blodgett Films
Authors: Zhang Chao , Tang Zheng-xin , Chen Qing-dong , Zhang Qing-guo , Du Zu-liang
Published: June 2008

X-ray diffraction (XRD) was used to investigate the microstructure and phase separation of mixed multilayers of cadmium stearate (SA) and behenate (BA) deposited onto hydrophilic glass by the Langmuir-Blodgett technique. No unitary fatty acid diffraction peaks in the XRD spectra of the mixed LB films, which reveals that domains in these samples are small and uniform. The interplanar spacing of the mixed LB films changes with the ratio of BA to SA in a step-shaped curve, which suggests that with the changing of the ratio between BA and SA, only three kinds of ordered structure form in the mixed system, and each microstructure, in particular, the short chains against long chains meshed microstructure can be maintained in a certain ratio range. In addition, for the meshed microstructure, the alkyl chains of both SA and BA stand straight or may have exactly the same small tilted angle from the substrate normal, as is indicated by the symmetric and asymmetric stretching vibration of methylene (CH2) peaks which are at 2847.80 and 2914.37 cm1 respectively in the Fourier transform infrared (FT-IR) transmission spectra. The mixed system always goes through a longitudinal regularity decreasing process when BA/SA is out of the intermediate ratio range (BA/SA: 1/5-1/1), which is illustrated by the relative XRD intensity changing with the ratio of BA/SA in a ``W'' shape. These results for the mixed LB films of BA/SA provide meaningful data for choosing the mixture ratio when fabricating composite films with special structure.
Anti-microfouling activities in extracts of two invasive algae:Grateloupia turuturuandSargassum muticum
Authors: Plouguerné Erwan , Hellio Claire , Deslandes Eric , Véron Benoît , Stiger-Pouvreau Valérie
Published: June 2008

Marine macroalgae are particularly prone to epiphytism. The colonisation of their surface may lead to severe perturbations and sometimes to the death of the host. To protect themselves against settling and/or competing organisms, many algae have developed defences against fouling by producing a wide variety of chemically active metabolites. The goal of this study was to investigate potential anti-microfouling activities of two introduced algal species from the Brittany coast (France),Sargassum muticum(Phaeophyceae) andGrateloupia turuturu(Rhodophyceae). Thus, a complete study of the antimicrobial activities of extracts (aqueous, acetone, chloroform, dichloromethane, diethyl-ether, ethyl acetate, ethanol 96°, hexane and methanol) fromS. muticumandG. turuturuagainst marine fouling bacteria (5 strains), fungi (5 strains) and biofilm-associated microphytobenthic strains (5) were performed. The most active extract ofG. turuturuwas the dichloromethane fraction, while the chloroform extract fromS. muticumshowed some good results. Our data suggest that these macroalgae can provide useful compounds or templates for industrial anti-microfouling applications.
Testing for Neutrality in Samples With Sequencing Errors
Authors: Achaz Guillaume
Published: June 2008

Many data sets one could use for population genetics contain artifactual sites, i.e., sequencing errors. Here, we first explore the impact of such errors on several common summary statistics, assuming that sequencing errors are mostly singletons. We thus show that in the presence of those errors, estimators of θ can be strongly biased. We further show that even with a moderate number of sequencing errors, neutrality tests based on the frequency spectrum reject neutrality. This implies that analyses of data sets with such errors will systematically lead to wrong inferences of evolutionary scenarios. To avoid to these errors, we propose two new estimators of θ that ignore singletons as well as two new tests Y and Y* that can be used to test neutrality despite sequencing errors. All in all, we show that even though singletons are ignored, these new tests show some power to detect deviations from a standard neutral model. We therefore advise the use of these new tests to strengthen conclusions in suspicious data sets.
Functional Characterization of the dRYBP Gene in Drosophila
Authors: González Inma , Aparicio Ricardo , Busturia Ana
Published: June 2008

The Drosophila dRYBP gene has been described to function as a Polycomb-dependent transcriptional repressor. To determine the in vivo function of the dRYBP gene, we have generated mutations and analyzed the associated phenotypes. Homozygous null mutants die progressively throughout development and present phenotypes variable both in their penetrance and in their expressivity, including disrupted oogenesis, a disorganized pattern of the syncytial nuclear divisions, defects in pattern formation, and decreased wing size. Although dRYBP mutations do not show the homeotic-like phenotypes typical of mutations in the PcG and trxG genes, they enhance the phenotypes of mutations of either the Sex comb extra gene (PcG) or the trithorax gene (trxG). Finally, the dRYBP protein interacts physically with the Sex comb extra and the Pleiohomeotic proteins, and the homeotic-like phenotypes produced by the high levels of the dRYBP protein are mediated through its C-terminal domain. Our results indicate that the dRYBP gene functions in the control of cell identity together with the PcG/trxG proteins. Furthermore, they also indicate that dRYBP participates in the control of cell proliferation and cell differentiation and we propose that its functional requirement may well depend on the robustness of the animal.
Comparative Genetics of Hybrid Incompatibility: Sterility in Two Solanum Species Crosses
Authors: Moyle Leonie C , Nakazato Takuya
Published: June 2008

The genetic basis of hybrid sterility can provide insight into the genetic and evolutionary origins of species barriers. We examine the genetics of hybrid incompatibility between two diploid plant species in the plant clade Solanum sect. Lycopersicon. Using a set of near-isogenic lines (NILs) representing the wild species Solanum pennellii (formerly Lycopersicon pennellii) in the genetic background of the cultivated tomato S. lycopersicum (formerly L. esculentum), we found that hybrid pollen and seed infertility are each based on a modest number of loci, male (pollen) and other (seed) incompatibility factors are roughly comparable in number, and seed-infertility QTL act additively or recessively. These findings are remarkably consistent with our previous analysis in a different species pair, S. lycopersicum × S. habrochaites. Data from both studies contrast strongly with data from Drosophila. Finally, QTL for pollen and seed sterility from the two Solanum studies were chromosomally colocalized, indicating a shared evolutionary history for these QTL, a nonrandom genomic distribution of loci causing sterility, and/or a proclivity of certain genes to be involved in hybrid sterility. We show that comparative mapping data can delimit the probable timing of evolution of detected QTL and discern which sterility loci likely evolved earliest among species.
The Temporal Dynamics of Processes Underlying Y Chromosome Degeneration
Authors: Bachtrog Doris
Published: June 2008

Y chromosomes originate from ordinary autosomes and degenerate by accumulating deleterious mutations. This accumulation results from a lack of recombination on the Y and is driven by interference among deleterious mutations (Muller's ratchet and background selection) and the fixation of beneficial alleles (genetic hitchhiking). Here I show that the relative importance of these processes is expected to vary over the course of Y chromosome evolution due to changes in the number of active genes. The dominant mode of degeneration on a newly formed gene-rich Y chromosome is expected to be Muller's ratchet and/or background selection due to the large numbers of deleterious mutations arising in active genes. However, the relative importance of these modes of degeneration declines rapidly as active genes are lost. In contrast, the rate of degeneration due to hitchhiking is predicted to be highest on Y chromosomes containing an intermediate number of active genes. The temporal dynamics of these processes imply that a gradual restriction of recombination, as inferred in mammals, will increase the importance of genetic hitchhiking relative to Muller's ratchet and background selection.
Quantitative Trait Locus-by-Environment Interaction for Milk Yield Traits on Bos taurus Autosome 6
Authors: Lillehammer Marie , Goddard Mike E , Nilsen Heidi , Sehested Erling , Olsen Hanne Gro , Lien Sigbjørn , Meuwissen Theo H E
Published: June 2008

Genotype-by-environment interactions for production traits in dairy cattle have often been observed, while QTL analyses have focused on detecting genes with general effects on production traits. In this study, a QTL search for genes with environmental interaction for the traits milk yield, protein yield, and fat yield were performed on Bos taurus autosome 6 (BTA6), also including information about the previously investigated candidate genes ABCG2 and OPN. The animals in the study were Norwegian Red. Eighteen grandsires and 716 sires were genotyped for 362 markers on BTA6. Every marker bracket was regarded as a putative QTL position. The effects of the candidate genes and the putative QTL were modeled as a regression on an environmental parameter (herd year), which is based on the predicted herd-year effect for the trait. Two QTL were found to have environmentally dependent effects on milk yield. These QTL were located 3.6 cM upstream and 9.1 cM downstream from ABCG2. No environmentally dependent QTL was found to significantly affect protein or fat yield.
The Direction of Linkage Disequilibrium: A New Measure Based on the Ancestral-Derived Status of Segregating Alleles
Authors: Takahasi K Ryo , Innan Hideki
Published: June 2008

A new measure of directional linkage disequilibrium is developed for detecting epistatic selection on interacting genes. Simulations show that by orienting the direction of linkage disequilibrium on the basis of the ancestral-derived status of alleles, the new measure indeed improves the power to detect a positive fitness interaction between two new mutations.
The Molecular Basis for Relative Physiological Functionality of the ADP/ATP Carrier Isoforms in Saccharomyces cerevisiae
Authors: Smith Christopher P , Thorsness Peter E
Published: June 2008

AAC2 is one of three paralogs encoding mitochondrial ADP/ATP carriers in the yeast Saccharomyces cerevisiae, and because it is required for respiratory growth it has been the most extensively studied. To comparatively examine the relative functionality of Aac1, Aac2, and Aac3 in vivo, the gene encoding each isoform was expressed from the native AAC2 locus in aac1Δ aac3Δ yeast. Compared to Aac2, Aac1 exhibited reduced capacity to support growth of yeast lacking mitochondrial DNA or of yeast lacking the ATP/Mg-Pi carrier, both conditions requiring ATP import into the mitochondrial matrix through the ADP/ATP carrier. Sixteen AAC1/AAC2 chimeric genes were constructed and analyzed to determine the key differences between residues or sections of Aac1 and Aac2. On the basis of the growth rate differences of yeast expressing different chimeras, the C1 and M2 loops of the ADP/ATP carriers contain divergent residues that are responsible for the difference(s) between Aac1 and Aac2. One chimeric gene construct supported growth on nonfermentable carbon sources but failed to support growth of yeast lacking mitochondrial DNA. We identified nine independent intragenic mutations in this chimeric gene that suppressed the growth phenotype of yeast lacking mitochondrial DNA, identifying regions of the carrier important for nucleotide exchange activities.
DNA Damage Differentially Activates Regional Chromosomal Loci for Tn7 Transposition in Escherichia coli
Authors: Shi Qiaojuan , Parks Adam R , Potter Benjamin D , Safir Ilan J , Luo Yun , Forster Brian M , Peters Joseph E
Published: June 2008

The bacterial transposon Tn7 recognizes replicating DNA as a target with a preference for the region where DNA replication terminates in the Escherichia coli chromosome. It was previously shown that DNA double-strand breaks in the chromosome stimulate Tn7 transposition where transposition events occur broadly around the point of the DNA break. We show that individual DNA breaks actually activate a series of small regional hotspots in the chromosome for Tn7 insertion. These hotspots are fixed and become active only when a DNA break occurs in the same region of the chromosome. We find that the distribution of insertions around the break is not explained by the exonuclease activity of RecBCD moving the position of the DNA break, and stimulation of Tn7 transposition is not dependent on RecBCD. We show that other forms of DNA damage, like exposure to UV light, mitomycin C, or phleomycin, also stimulate Tn7 transposition. However, inducing the SOS response does not stimulate transposition. Tn7 transposition is not dependent on any known specific pathway of replication fork reactivation as a means of recognizing DNA break repair. Our results are consistent with the idea that Tn7 recognizes DNA replication involved in DNA repair and reveals discrete regions of the chromosome that are differentially activated as transposition targets.
A Genetic Screen for Increased Loss of Heterozygosity inSaccharomyces cerevisiae
Authors: Andersen Marguerite P , Nelson Zara W , Hetrick Elizabeth D , Gottschling Daniel E
Published: June 2008

Loss of heterozygosity (LOH) can be a driving force in the evolution of mitotic/somatic diploid cells, and cellular changes that increase the rate of LOH have been proposed to facilitate this process. In the yeast Saccharomyces cerevisiae, spontaneous LOH occurs by a number of mechanisms including chromosome loss and reciprocal and nonreciprocal recombination. We performed a screen in diploid yeast to identify mutants with increased rates of LOH using the collection of homozygous deletion alleles of nonessential genes. Increased LOH was quantified at three loci (MET15, SAM2, and MAT) on three different chromosomes, and the LOH events were analyzed as to whether they were reciprocal or nonreciprocal in nature. Nonreciprocal LOH was further characterized as chromosome loss or truncation, a local mutational event (gene conversion or point mutation), or break-induced replication (BIR). The 61 mutants identified could be divided into several groups, including ones that had locus-specific effects. Mutations in genes involved in DNA replication and chromatin assembly led to LOH predominantly via reciprocal recombination. In contrast, nonreciprocal LOH events with increased chromosome loss largely resulted from mutations in genes implicated in kinetochore function, sister chromatid cohesion, or relatively late steps of DNA recombination. Mutants of genes normally involved in early steps of DNA damage repair and signaling produced nonreciprocal LOH without an increased proportion of chromosome loss. Altogether, this study defines a genetic landscape for the basis of increased LOH and the processes by which it occurs.
Genetic Analysis of Heterosis for Yield and Yield Components in Rapeseed (Brassica napus L.) by Quantitative Trait Locus Mapping
Authors: Radoev Mladen , Becker Heiko C , Ecke Wolfgang
Published: June 2008

The main objective in this research was the genetic analysis of heterosis in rapeseed at the QTL level. A linkage map comprising 235 SSR and 144 AFLP markers covering 2045 cM was constructed in a doubled-haploid population from a cross between the cultivar “Express” and the resynthesized line “R53.” In field experiments at four locations in Germany 250 doubled-haploid (DH) lines and their corresponding testcrosses with Express were evaluated for grain yield and three yield components. The heterosis ranged from 30% for grain yield to 0.7% for kernel weight. QTL were mapped using three different data sets, allowing the estimation of additive and dominance effects as well as digenic epistatic interactions. In total, 33 QTL were detected, of which 10 showed significant dominance effects. For grain yield, mainly complete dominance or overdominance was observed, whereas the other traits showed mainly partial dominance. A large number of epistatic interactions were detected. It was concluded that epistasis together with all levels of dominance from partial to overdominance is responsible for the expression of heterosis in rapeseed.
Biochemical alterations in patients with Down syndrome
Authors: Varga Petra , V. Oláh Anna , Oláh Éva
Published: June 2008

A Down-kór a 21-es kromoszóma triszómiája okozta értelmi fogyatékosság jellemző klinikai tünetekkel. A genetikai alapeltérés nem gyógyítható, de a kísérő tünetek befolyásolása javíthatja a beteg életminőségét.Célkitűzés:A szerzők összefüggést kerestek a kórképért felelős gének és a háttérben megfigyelhető biokémiai változások között. A szuperoxid-dizmutáz, a cisztation-béta-szintáz és az S100B fehérjegének fokozott expressziójával kapcsolatos paraméterek: a szérumantioxidáns-kapacitás és a sejten kívüli antioxidánsok (transzferrin, ferritin, összfehérje, albumin és bilirubin) vizsgálata mellett a homocisztein-anyagcsere megítélésére a homocisztein-, folsav- és B12-vitamin-koncentrációt, a vascularis károsodás megítélésére az S-100B fehérje és a szérum-N-acetil-béta-D-glükózaminidáz aktivitását mérték.Módszerek:Az antioxidáns-kapacitás (Stocks,1974), a homocisztein (HPLC), a folsav (‘capture’, IMX-Abbott), a B12-vitamin (MEIA, IMX-Abbott) és az S100B fehérje meghatározása kemilumineszcens szendvics immunoassay módszerrel, a szérum-N-acetil-béta-D-glükózaminidáz aktivitásának mérése pedig spektrofotometriásan történt.Eredmények:A plazmahomocisztein 7/30 esetben alacsonyabb, 6/30 betegben pedig magasabb volt, mint a referenciatartomány. A relatív homociszteinérték 95 ± 21%. A plazma relatív folsavértéke (a normálérték százalékában kifejezve) 85 ± 51%, a B12-vitamin 78 ± 30% volt. 2/30 betegben igazoltak folsav-, és 2/30 betegben B12-hiányt. A Down-kóros és az egészséges gyermekek antioxidánsaktivitás-értékei nem különböztek szignifikánsan, bár a felnőtt-referenciatartományt (90–100%) egyikük sem érte el. Emelkedést észleltek az S100B fehérje koncentrációjában (átlag: 0,68 ± 0,27 µg/l), amely a referenciatartomány felső határa (egyéves kor felett > 0,15 µg/l) négy-nyolcszorosának bizonyult. A szérum-N-acetil-béta-D-glükózaminidáz aktivitásának átlaga a referenciatartományon (10–30 U/l) belül maradt. Az N-acetil-béta-D-glükózaminidáz- és az antioxidáns-aktivitás között statisztikailag szignifikáns korreláció nem igazolódott.Következtetések:A Down-kórban talált alacsonyabb homocisztein-, folsav- és B12-vitamin-érték a megnövekedett cisztation-béta-szintáz-aktivitás következménye lehet („atheroma free model”). Az antioxidáns-aktivitás szignifikáns eltérést nem mutatott. A szerzők feltételezik, hogy a szuperoxid-dizmutáz fokozott expressziója következtében termelődő hidrogén-peroxidot az indukált glutation-peroxidáz és kataláz bontja le, így az antioxidáns-rendszer egyensúlya megmarad. Emellett szól, hogy a szérum-N-acetil-béta-D-glükózaminidáz eredményei nem utaltak érkárosodásra. Az S100B fehérje magas értékei viszont agykárosodást jeleznek, amely az életkorral súlyosbodik. Ezek alapján a szerzők javasolják a fenti paraméterek rendszeres kontrollját. Indokoltnak tartják a folsav pótlását, mivel az javíthatja a tanulási képességet, lassítja az Alzheimer-kóros tünetek kifejlődését, azaz jobb életminőséget biztosít.
Detection of Larval Remains after Consumption by Fishes
Authors: Schooley Jason D. , Karam Abraham P. , Kesner Brian R. , Marsh Paul C. , Pacey Carol A. , Thornbrugh Darren J.
Published: June 2008

In southwestern North America, consumption of native fish larvae by nonnative predators has imperiled native populations. Field‐acquired dietary analyses have provided little evidence of this cause‐effect relationship. In this study, small, nonnative green sunfish Lepomis cyanellus, bluegills L. macrochirus, red shiners Cyprinella lutrensis, fathead minnow Pimephales promelas, and yellow bullheads Ameiurus natalis were each fed a single larva of the native razorback sucker Xyrauchen texanus. Gut content analysis revealed that prey detection generally became increasingly difficult over a short postconsumption time period under laboratory conditions. For green sunfish, bluegills, and yellow bullheads, significant relationships between prey detection and time were revealed; the probability of prey identification was initially 50% or greater for about 30 min postconsumption, whereas few prey (3%) were identifiable at 60 min postconsumption. For red shiners and fathead minnow (pooled for analysis), no relationship was evident; these two species completely masticated their prey, thus hindering identification. Green sunfish and bluegills swallowed prey whole, and yellow bullheads damaged larvae during consumption. Many larvae were discovered in the foregut, and 25% were regurgitated during predator fixation. Use of gut content analysis as evidence of predation on native fish larvae by small, nonnative fish is problematic and unreliable due to rapid mechanical and chemical digestion of fragile larval tissues.
Limiares de reconhecimento de sentenças no ruído, em campo livre: valores de referência para adultos normo-ouvintes
Authors: Henriques Marília Oliveira , Miranda Elisiane Crestani de , Costa Maristela Julio
Published: June 2008

Nas clínicas de audiologia, as queixas de dificuldade de compreensão da fala em ambientes ruidosos são freqüentes, mesmo para indivíduos normo-ouvintes. Assim, o audiologista deve não só identificar uma perda auditiva, mas também analisar a compreensão da fala, em condições de comunicação próximas às encontradas no cotidiano. OBJETIVO: Determinar o valor de referência para os limiares de reconhecimento de sentenças no ruído, em campo livre, para indivíduos adultos normo-ouvintes. MATERIAL E MÉTODO: O experimento foi realizado nos anos de 2005 e 2006. Participaram da pesquisa 150 indivíduos adultos normo-ouvintes, com idade entre 18 e 64 anos, avaliados em cabine acusticamente tratada. Realizou-se a avaliação a partir da aplicação do teste Listas de Sentenças em Português. As listas de sentenças foram apresentadas em campo livre, na presença de um ruído competitivo, na intensidade fixa de 65 dB A. O ângulo de incidência de ambos os estímulos foi de 0º- 0º azimute. RESULTADOS E CONCLUSÃO: Os limiares de reconhecimento de sentenças em campo-livre foram obtidos na relação sinal-ruído de -8,14 dB A, sendo este o valor de referência para indivíduos normo-ouvintes.
Reabilitação fonatória do laringectomizado total: utilização de toxina botulínica na voz tráqueo-esofágica com prótese fonatória
Authors: Chone Carlos Takahiro , Teixeira Cristiane , Andreollo Nelson A. , Spina Ana Lucia , Barcelllos Irene H.K. , Quagliato Elizabeth , Crespo Agricio N.
Published: June 2008

Na punção tráqueo-esofágica(PTE) é realizada miotomia do músculo constritor da faringe, mas sua necessidade é entre 9% a 79% dos pacientes. Sua realização pode aumentar as taxas de fístula salivar no pós-operatório. A aplicação da TB é ambulatorial. OBJETIVO: Análise da eficácia da aplicação de toxina botulínica (TB), na reabilitação do laringectomizado total com voz tráqueo-esofágica(VTE) com espasmo(E) do segmento faringo-esofágico (SFE) sem miotomia. MATERIAL E MÉTODOS: Análise de oito pacientes submetidos à laringectomia total (LT), reabilitados com VTE com prótese fonatória (PF), esforço para emissão de voz devido à E do SFE. Todos submetidos a tratamento dessa alteração motora com injeção de 100 unidades de TB no SFE. A avaliação constituiu-se de análise perceptiva de voz, videofluoroscopia (VF) do SFE, análise acústica de voz e manometria computadorizada (MC) do SFE, todos antes e após aplicação de TB. DESENHO DE ESTUDO: Estudo prospectivo. RESULTADOS: Houve diminuição na pressão à MC do SFE, após a injeção de TB. Análise acústica demonstrou melhora na qualidade de harmônicos após o tratamento. Houve emissão de voz sem esforço e melhora do E após o uso da TB. CONCLUSÃO: Todos os pacientes com E do SFE apresentaram melhora vocal após aplicação da TB neste SFE.
Achados otoscópicos e timpanométricos em lactentes com fissura labiopalatina
Authors: Feniman Mariza Ribeiro , Souza Adriana Guerta de , Jorge José Carlos , Lauris José Roberto Pereira
Published: June 2008

A timpanometria tem papel fundamental na identificação de alterações de orelha média, as quais são de grande ocorrência na população com fissura labiopalatina. OBJETIVO: Analisar de maneira retrospectiva os resultados dos exames otoscópicos e timpanométricos de lactentes com fissura labiopalatina não operados. Estudo retrospectivo. MATERIAL E MÉTODO: Foram analisados 273 prontuários de lactentes, portadores de fissura labiopalatina, submetidos de março de 1996 a abril de 2002 a otoscopia pneumática e a timpanometria com a sonda 226Hz. RESULTADOS: Não foi encontrada significância estatística nos achados otoscópicos e timpanométricos considerando os gêneros e orelhas. Observou-se 84% de alteração na otoscopia (opacificação/83,4%, fluido visível na orelha média/1,5%, imobilidade de membrana timpânica na insuflação/1,8 e retração/0,7) e 65% nas curvas timpanométricas (B/38%), A/36,5%, As/21%, C/4% e Ad/0,5%). CONCLUSÃO: Os lactentes portadores de fissura labiopalatina do gênero feminino e do masculino não diferiram nas curvas timpanométricas e nos achados otoscópicos. Todos os tipos de curvas timpanométricas estiveram presentes, sendo as do tipo B e A de maior ocorrência. A opacificação de membrana timpânica foi o achado otoscópico mais freqüente. A otoscopia pneumática identificou maior número de alteração que a timpanometria convencional.
Mecanismos de ação dos corticosteróides na polipose rinossinusal
Authors: Fernandes Atílio Maximino , Valera Fabiana Cardoso Pereira , Anselmo-Lima Wilma T.
Published: June 2008

Os glicocorticóides (GC) são drogas de escolha no tratamento clínico da polipose nasossinusal conforme recomendação da literatura. Entretanto, seus mecanismos de ação nas regressões dos sintomas clínicos e dos pólipos não são totalmente compreendidos. Sabe-se que a administração tópica e ou sistêmica dos glicocorticóides leva a variações na expressão de citocinas, quimiocinas e linfocinas, além das alterações celulares. Assim, os GC suprimem a expressão de citocinas pró-inflamatórias, de quimiocinas, de moléculas de adesão, além de estimular a transcrição de citocinas antiinflamatórias. Citocinas pró-fibróticas como a IL-11, fator básico de crescimento do fibroblasto (b-FGF) e fator de crescimento endotelial vascular (VEGF), relacionados com o crescimento do pólipo, também são suprimidos pela ação do GC. Tal ação depende fundamentalmente da interação com os seus receptores (GR), pois alguns indivíduos apresentam algum grau de resistência celular ao seu efeito, que parece estar relacionada com a presença da isoforma b do GR. Genes envolvidos nas fases de produção de imunoglobulinas, apresentação e processamento do antígeno também sofrem ação dos GC de forma variada. OBJETIVOS: Fazer uma revisão da literatura sobre os mecanismos de ação do GC na PNS. CONCLUSÃO: A compreensão desses mecanismos implicará no desenvolvimento de drogas mais eficazes na sua terapêutica.
Papiloma invertido bilateral: relato de caso e revisão da literatura
Authors: Salomone Raquel , Matsuyama Cícero , Giannotti Filho Osvaldo , Alvarenga Marcia Lanzoni De , Martinez Neto Eulógio Emílio , Chaves Adriana Gonzaga
Published: June 2008

O papiloma invertido é um raro tumor nasossinusal benigno e unilateral. As manifestações clínicas são inespecíficas, como obstrução nasal unilateral, rinorréia, epistaxe, hiposmia e cefaléia. O diagnóstico é realizado por meio de anamnese detalhada, exame otorrinolaringológico e exames complementares. A tomografia computadorizada e a ressonância magnética são exames fundamentais na elucidação diagnóstica, no tratamento e no acompanhamento do paciente. O tratamento é essencialmente cirúrgico. Este trabalho tem como objetivo relatar um caso de papiloma invertido bilateral e realizar uma revisão da literatura.
Otosclerose infantil: relato de caso e revisão da literatura
Authors: Salomone Raquel , Riskalla Paulo Emmanuel , Vicente Andy de Oliveira , Boccalini Maria Carmela Cundari , Chaves Adriana Gonzaga , Lopes Renata , Felin Filho Gilberto Bolivar
Published: June 2008

A otospongiose é uma osteodistrofia do osso temporal caracterizada pela reabsorção e neoformação óssea desordenada. Clinicamente, caracteriza-se por disacusia condutiva, neurossensorial, e/ou mista, progressiva e zumbidos. O início dos sintomas ocorre entre 30 e 40 anos de idade sendo rara sua manifestação na infância. Descrevemos o caso de um paciente de 11 anos de idade, com quadro de hipoacusia unilateral progressiva há 5 anos. O exame otorrinolaringológico revelou mancha rubra de Schwartze em orelha esquerda. A audiometria, imitanciometria e a tomografia computadorizada demonstraram características sugestivas de otospongiose. Realizamos uma revisão dos aspectos clínicos, diagnósticos e da conduta terapêutica da otospongiose na infância.
Tumores nasossinusais raros: série de casos e revisão de literatura
Authors: Araújo Roberta de Paula , Gomes Érika Ferreira , Menezes Dalgimar Beserra de , Ferreira Lidiane Maria de Brito Macedo , Rios Adson Sales do Nascimento
Published: June 2008

Os tumores nasossinusais são patologias pouco freqüentes na prática clínica. Aproximadamente 0,8% de todos os cânceres humanos localizam-se nessa região. Apesar de rara, a neoplasia nasossinusal manifesta-se habitualmente através de sintomas inespecíficos e comuns a inúmeras patologias inflamatórias. Este estudo se propõe a descrever uma série de casos de tumores nasossinusais não-epiteliais raros, incluindo estesioneuroblastoma, granuloma central de células gigantes, plasmocitoma extramedular, hemangiopericitoma sinonasal, neurofibroma e fibroma cemento-ossificante, diagnosticados no Hospital Geral de Fortaleza, SESA/SUS. Faz-se uma breve revisão de literatura de cada patologia, salientando-se a necessidade do diagnóstico anatomopatológico preciso para condução adequada de cada caso.
Fazendas de café oitocentistas no Vale do Paraíba
Authors: Carrilho Marcos José
Published: June 2008

As edificações remanescentes das fazendas de café do Vale do Paraíba constituem notáveis expressões da arquitetura rural paulista. O estudo de seus componentes e a compreensão de sua organização são aqui abordados mediante a leitura de textos, da época, sobre o cultivo de café e o exame de inventários de bens de seus proprietários. Na parte final, este enfoque é desdobrado na análise da arquitetura desses estabelecimentos.
Engenhos e fazendas de café em Campinas (séc. XVIII - séc. XX)
Authors: Silva Áurea Pereira da
Published: June 2008

O artigo estuda a produção arquitetônica rural do município de Campinas legada por dois ciclos econômicos: o da cana-de-açúcar e o do café, a partir do final do século XVIII e no século XIX. Analisa a documentação historiográfica, inventários (arquivos do Centro de Memória da Unicamp) e testemunhos materiais arrolados nos levantamentos de campo. Aborda os edifícios a partir da implantação, no terreno, das diversas formas de agenciamento (no caso da produção cafeeira, a disposição dos edifícios determinada pelo fluxo das operações e tarefas de beneficiamento do grão) e dos múltiplos programas necessários ao setor produtivo e às habitações. Enfatiza a questão tecnológica dos edifícios, revelando a preferência pelos métodos e materiais tradicionais da cultura arquitetônica paulista, particularizada no domínio da taipa de pilão e da taipa de mão até a chegada da ferrovia, na década de 1870.
Le musée d’histoire en France entre traditions nationales et soucis identitaires
Authors: Poulot Dominique
Published: June 2008

Les musées d’histoire ont connu durant les dernières décennies en France des mutations rapides, marquées par une série de constructions ou de rénovations. L’histoire de tels chantiers, intervenus plus tardivement par rapport aux autres types de musées, permet de s’interroger sur les rapports nouveaux tissés à ces occasions entre musées d’histoire et historiographie savante. On constate que le musée d’histoire, aujourd’hui, est davantage un musée du présent qu’un musée érudit au sens traditionnel du terme. Refusant la nostalgie, le musée idéal doit élaborer une nouvelle représentation du patrimoine conçue comme une dynamique inédite du « patrimoine » dans la société. L’enjeu est de refuser une marchandisation spectaculaire de l’histoire qui exclut l’approche critique et savante, tout en combattant l’éventuelle disparition de la spécificité muséographique derrière le seul savoir historien, aux dépens des revendications de la mémoire sociale. Dans ces conditions, le rapport du patrimoine et de l’écriture de l’histoire devient un enjeu central pour les musées d’histoire.
Radiographic diagnosis of incipient proximal caries: an ex-vivo study
Authors: Silva Neto José Moreira da , Santos Rosenês Lima dos , Sampaio Maria Carmeli Correia , Sampaio Fábio Correia , Passos Isabela Albuquerque
Published: June 2008

The aim of this ex vivo study was to compare visual clinical and radiographic examinations to the histological analysis for proximal caries diagnosis in extracted permanent molars and premolars. The relationship between clinical aspects and carious lesions was also evaluated. Eighty-eight proximal surfaces (44 freshly extracted teeth) were longitudinally sectioned with a 370-µm diamond disk, thinned with wet silicon carbide paper and observed with a stereomicroscope at x40 magnification. Sensitivity and specificity were 65.6% and 83.3% for clinical examination and 29.7% and 95.8% for radiographic examination, respectively. Kappa values ranged from 0.64 to 0.91. The white spots corresponded to lesions restricted to enamel, while the dark spots corresponded to lesions that reached the dentinoenamel junction. In most cases, cavitation corresponded to dentin lesions. It may be concluded that interproximal radiographic examination is not a reliable method for detection of incipient proximal carious lesions.
Surface finishing of unused rotary endodontic instruments: a SEM study
Authors: Chianello Giovani , Specian Vivyane Leal , Hardt Lilian Cristina Fucuda , Raldi Denise Pontes , Lage-Marques José Luiz , Habitante Sandra Márcia
Published: June 2008

During endodontic therapy, cleaning of root canals is performed using endodontic files and auxiliary chemical substances, and it is important that the endodontist be familiar with the instruments used in daily practice. This study evaluated, under scanning electron microscopy (SEM), the quality of the surface finishing of unused rotary endodontic instruments. Fifty sizes 20, 25 and 30 rotary files from different commercial brands (ProFile, Protaper, Race, Hero and K3 Endo) were removed directly from their packages and had their final 3 mm examined with a scanning electron microscope at x190 magnification with no previous preparation. The images were evaluated by 3 skillful, calibrated, blinded observers according to the following criteria: cutting edge, debris, grooves, microcavities, tip shape, tip position, scraping and transition angle. Data were recorded in worksheets designed for the study. Irregular edges were observed in 50-100% of the files. Except for ProFile, all commercial brands presented surface debris in 100% of samples. Only Race files showed no grooves or microcavities. K3 Endo files presented the best tip centralization. Excetp for ProTaper files, all commercial brands presented blunt-cutting edges in 100% of samples. All types of files presented surface scraping. K3 Endo files and Protaper had a high percentage of transition angle. Based on the evaluation criteria used in the present study, most samples presented a minimum of 2 alterations and a maximum of 7 alterations per instrument. Under the tested conditions, the quality of the surface finishing of the examined instruments was not as expected, given that no instrument was free of imperfections and most of them presented at least 2 and up to 7 types of surface defects. These results suggest that the manufacturing process and the packaging conditions of rotary endodontic instruments are far from ideal.
External location of the buccinator muscle to facilitate electromyographic analysis
Authors: Silva Regina Helena Barbosa Tavares da , Porciúncula Hélio Ferraz , Jardini Renata Savastano Ribeiro , Pita Ana Paula Gonçalves , Ribeiro Ana Paula Dias
Published: June 2008

Electromyography is frequently used to measure the activity of masticatory muscles. It requires the precise setting of the electrodes, which demands the accurate location of the muscle to be evaluated. The purpose of this study was to investigate the accuracy of an external method to locate the buccinator muscle. Fifteen human cadavers were evaluated and planes were determined on the face using anatomic landmarks. An angle (a) was obtained at the intersection of these planes on the central point of buccinator muscle and measured with a protractor. The value of the angle allows locating the central point of buccinator muscle based on anatomic landmarks on the face. Statistical analysis of the collected data indicated an angle of 90º with 95% reliability, thus proving the efficacy of the proposed method.