971 resultados para Golgi Apparatus
Resumo:
The Road Rater is a dynamic deflection measuring appa-ratus for flexible base pavements. The basic operating principle of the Road Rater is to impart a dynamic loading and measure the resultant movement of the pavement with velocity sensors. This data, when properly adjusted for temperature by use of a nomograph included in this report, can be used to determine pavement life expectancy and estimate overlay thickness required. Road Rater testing will be conducted in the spring, when pave-ments are in their weakest condition, until seasonal correction factors can be developed. The Road Rater does not have sufficient ram weight to effectively evaluate load carrying capacity of rigid pavements. All rigid pavements react similarly to Road Rater testing and generally deflect from 0.65 to 1.30 mils. Research will be continued to evaluate rigid pavements with the Road Rater, however. The Road Rater has proven to be a reliable, trouble free pavement evaluation machine. The deflection apparatus was originally front-mounted, but was rear-mounted during the winter of 1977-78. Since that time, van handling has greatly improved, and front suspension parts are no longer overstressed due to improper weight distribution. The Road Rater provides a fast, economical, nondestructive test method to evaluate flexible pavements. Road Rater test data can be used to predict pavement life, set priorities for asphaltic concrete resurfacing, and design asphaltic concrete overlays. Temperature and seasonal variations significantly affect Road Rater deflection readings and must be considered. A nomograph included in this report adjusts for temperature, but does not correct for seasonal effect. Road Rater testing will be conducted in the spring until seasonal correction factors can be developed. The Road Rater has not successfully evaluated rigid pavements, but research will continue in this area. 1. Recommendations for continuing Road Rater research, evaluation and application are as follows:A computer program should be established to reduce Road Rater raw data (Range and Sensor reading) to HR-178 Road Rater Dynamic Deflections For Determining Structural Rating Of Flexible Pavements mean deflection (mils) and/or structural rating. This computer printout would be similar to present friction testing printouts, and would greatly reduce Road Rater data reduction manpower needs and costs. 2. Seasonal variation study should continue to develop seasonal correction factors. Seasonal test roads will be studied concurrently with routine testing during 1979 to develop this relationship. All Road Rater testing will be conducted in the spring until the seasonal relationship is established. 3. An asphaltic concrete overlay design method should be established based on Road Rater de-flection readings. The AASHTO Interim Guide for Design of Pavement Structures 1972 will be used as a base document for this study. 4. AASHTO Structural numbers should be compared to Road Rater Structural Ratings during 1979 on asphaltic concrete overlay projects. This analysis will enable us to refine Road Rater evaluation of flexible pavements. Roads will be tested before resurfacing and several months
Resumo:
Previous studies have demonstrated that poultry house workers are exposed to very high levels of organic dust and consequently have an increased prevalence of adverse respiratory symptoms. However, the influence of the age of broilers on bioaerosol concentrations has not been investigated. To evaluate the evolution of bioaerosol concentration during the fattening period, bioaerosol parameters (inhalable dust, endotoxin and bacteria) were measured in 12 poultry confinement buildings in Switzerland, at three different stages of the birds' growth; samples of air taken from within the breathing zones of individual poultry house employees as they caught the chickens ready to be transported for slaughter were also analysed. Quantitative polymerase chain reaction (Q-PCR) was used to assess the quantity of total airborne bacteria and total airborne Staphylococcus species. Bioaerosol levels increased significantly during the fattening period of the chickens. During the task of catching mature birds, the mean inhalable dust concentration for a worker was 26 +/- 1.9 mg m(-3) and endotoxin concentration was 6198 +/- 2.3 EU m(-3) air, >6-fold higher than the Swiss occupational recommended value (1000 EU m(-3)). The mean exposure level of bird catchers to total bacteria and Staphylococcus species measured by Q-PCR is also very high, respectively, reaching values of 53 (+/-2.6) x 10(7) cells m(-3) air and 62 (+/-1.9) x 10(6) m(-3) air. It was concluded that in the absence of wearing protective breathing apparatus, chicken catchers in Switzerland risk exposure beyond recommended limits for all measured bioaerosol parameters. Moreover, the use of Q-PCR to estimate total and specific numbers of airborne bacteria is a promising tool for evaluating any modifications intended to improve the safety of current working practices
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Tumor-host interaction is a key determinant during cancer progression, from primary tumor growth to metastatic dissemination. At each step, tumor cells have to adapt to and subvert different types of microenvironment, leading to major phenotypic and genotypic alterations that affect both tumor and surrounding stromal compartments. Understanding the molecular mechanisms that govern tumor-host interplay may be essential for better comprehension of tumorigenesis in an effort to improve current anti-cancer therapies. The present work is composed of two projects that address tumor-host interactions from two different perspectives, the first focusing on the characterization of tumor-associated stroma and the second on membrane trafficking in tumor cells. Part 1. To selectively address stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to analyze the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Comparison showed that invasive breast and prostate cancer elicit distinct, tumor-specific stromal responses, with a limited panel of shared induced and/or repressed genes. Both breast and prostate tumor-specific deregulated stromal gene sets displayed statistically significant survival-predictive ability for their respective tumor type. By contrast, a stromal gene signature common to both tumor types did not display prognostic value, although expression of two individual genes within this common signature was found to be associated with patient survival. Part 2. GLG1 is known as an E-selectin ligand and an intracellular FGF receptor, depending on cell type and context. Immunohistochemical and immunofluorescence analyses showed that GLG1 is primarily localized in the Golgi of human tumor cells, a central location in the biosynthetic/secretory pathways. GLG1 has been shown to interact with and to recruit the ARF GEF BIGI to the Golgi membrane. Depletion of GLG1 or BIGI markedly reduced ARF3 membrane localization and activation, and altered the Golgi structure. Interestingly, these perturbations did not impair constitutive secretion in general, but rather seemed to impair secretion of a specific subset of proteins that includes MMP-9. Thus, GLG1 coordinates ARF3 activation by recruiting BIGI to the Golgi membrane, thereby affecting secretion of specific molecules. - Les interactions tumeur-hôte constituent un élément essentiel à la progression tumorale, de la croissance de la tumeur primaire à la dissémination des métastases. A chaque étape, les cellules tumorales doivent s'adapter à différents types de microenvironnement et les détourner à leur propre avantage, donnant lieu à des altérations phénotypiques et génotypiques majeures qui affectent aussi bien la tumeur elle-même que le compartiment stromal environnant. L'étude des mécanismes moléculaires qui régissent les interactions tumeur-hôte constitue une étape essentielle pour une meilleure compréhension du processus de tumorigenèse dans le but d'améliorer les thérapies anti cancer existantes. Le travail présenté ici est composé de deux projets qui abordent la problématique des interactions tumeur-hôte selon différentes perspectives, le premier se concentrant sur la caractérisation du stroma tumoral et le second sur le trafic intracellulaire des cellules tumorales. Partie 1. Pour examiner les changements d'expression des gènes dans le stroma en réponse à la progression du cancer, des puces à ADN Affymetrix ont été utilisées afin d'analyser les transcriptomes des cellules stromales issues de carcinomes invasifs du sein et de la prostate et collectées par microdissection au laser. L'analyse comparative a montré que les cancers invasifs du sein et de la prostate provoquent des réponses stromales spécifiques à chaque type de tumeur, et présentent peu de gènes induits ou réprimés de façon similaire. L'ensemble des gènes dérégulés dans le stroma associé au cancer du sein, ou à celui de la prostate, présente une valeur pronostique pour les patients atteints d'un cancer du sein, respectivement de la prostate. En revanche, la signature stromale commune aux deux types de cancer n'a aucune valeur prédictive, malgré le fait que l'expression de deux gènes présents dans cette liste soit liée à la survie des patients. Partie 2. GLG1 est connu comme un ligand des sélectines E ainsi que comme récepteur intracellulaire pour des facteurs de croissances FGFs selon le type de cellule dans lequel il est exprimé. Des analyses immunohistochimiques et d'immunofluorescence ont montré que dans les cellules tumorales, GLG1 est principalement localisé au niveau de l'appareil de Golgi, une place centrale dans la voie biosynthétique et sécrétoire. Nous avons montré que GLG1 interagit avec la protéine BIGI et participe à son recrutement à la membrane du Golgi. L'absence de GLG1 ou de BIGI réduit drastiquement le pool d'ARF3 associé aux membranes ainsi que la quantité d'ARF3 activés, et modifie la structure de l'appareil de Golgi. Il est particulièrement intéressant de constater que ces perturbations n'ont pas d'effet sur la sécrétion constitutive en général, mais semblent plutôt affecter la sécrétion spécifique d'un sous-groupe défini de protéines comprenant MMP-9. GLG1 coordonne donc l'activation de ARF3 en recrutant BIGI à la membrane du Golgi, agissant par ce moyen sur la sécrétion de molécules spécifiques.
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Objective: To determine the variation in prevalence of temporomandibular disorders (TMD), other side effects, and technical complications during 5 years of sleep apnea treatment with a mandibular advancement device. Materials and Methods: Forty patients diagnosed with obstructive sleep apnea received an adjustable appliance at 70% of the maximum protrusion. The protrusion was then progressively increased. TMD (diagnosed according to the Research Diagnostic Criteria for TMD), overjet, overbite, occlusal contacts, subjective side effects, and technical complications were recorded before and a mean of 14, 21, and 58 months after treatment and analyzed by the Wilcoxon test (P Less-than .05). Results: Fifteen patients still used the oral appliance at the 5-year follow-up, and no significant variation in TMD prevalence was observed. Subjective side effects were common, and a significant reduction was found in overjet, overbite, and in the number of occlusal contacts. Furthermore, the patients made a mean of 2.5 unscheduled dental visits per year and a mean of 0.8 appliance repairs/relines per year by a dental technician. The most frequent unscheduled visits were needed during the first year and were a result of acrylic breakage on the lateral telescopic attachment, poor retention, and other adjustments to improve comfort. Conclusions: Five-year oral appliance treatment does not affect TMD prevalence but is associated with permanent occlusal changes in most sleep apnea patients during the first 2 years. Patients seek several unscheduled visits, mainly because of technical complications.
Resumo:
Results are presented of triaxial testing of three crushed limestones to which either hydrated high-calcium lime, sodium chloride or calcium chloride had been added. Lime was added at rates of 1, 3, 10 and 16 percent, chlorides were added at 0.5 percent rate only. Speciments were compacted using vibratory compaction apparatus and were tested in triaxial compression using lateral pressures from 10 to 100 psi. Triaxial test results indicate that: (1) sodium chloride slightly decreased the angle of internal friction and increased cohesion, (2) calcium chloride slightly increased the angle of internal friction and decreased cohesion, and (3) lime had no appreciable effect on angle of internal friction but increased cohesion, decreased density and increased pore water pressure.
Resumo:
The liquid and plastic limits of a soil are consistency limits that were arbitrarily chosen by Albert Atterberg in 1911. Their determination is by strictly empirical testing procedures. Except for the development of a liquid limit device and subsequent minor refinements the method has remained basically unchanged for over a half century. The empirical determination of an arbitrary limit would seem to be contrary to the very foundations of scientific procedures. However, the tests are relatively simple and the results are generally acceptable and valuable in almost every conceivable use of soil from an engineering standpoint. Such a great volume of information has been collected and compiled by application of these limits to cohesive soils, that it would be impractical and virtually impossible to replace the tests with a more rational testing method. Nevertheless, many believe that the present method is too time consuming and inconsistent. Research was initiated to investigate the development of a rapid and consistent method by relating the limits to soil moisture tension values determined by porous plate and pressure membrane apparatus. With the moisture tension method, hundreds of samples may be run at one time, operator variability is minimal, results are consistent, and a high degree of correlation to present liquid limit tests is possible.
Resumo:
The Road Rater is a dynamic deflection measuring apparatus for flexible base pavements. The Road Rater replaces the Benkelman Beam which was last used by the Iowa DOT in 1977. Road Rater test results correlate reasonably well (correlation coefficient = 0.83) with Benkelman Beam test data. The basic differences between the Road Rater and Benkelman Beam are as follows: 1. The Benkelman Beam uses a static 18,000 lb. load while the Road Rater uses a dynamic 800 to 2,000 lb. loading. 2. The Road Rater tests much faster and more economically than the Benkelman Beam. 3. The Road Rater better simulates a moving truck than the Benkelman Beam. The basic operating principle of the Road Rater is to impart a dynamic loading and measure the resultant movement of the pavement with velocity sensors. This data, when properly adjusted for temperature by use of a nomograph included in this report, can be used to determine pavement life expectancy and estimate overlay thickness required. Road Rater testing will be conducted in the spring, when pavements are in their weakest condition, until seasonal correction factors can be developed. The Road Rater does not have sufficient ram weight to effectively evaluate load carrying capacity of rigid pavements. All rigid pavements react similarly to Road Rater testing and generally deflect from 0.65 to 1.30 mils. Research will be contined to evaluate rigid pavements with the Road Rater, however. The Road Rater has proven to be a reliable, troublefree pavement evaluation machine. The deflection apparatus was originally front-mounted,but was rear-mounted during the winter of 1977-78. Since that time, van handling has greatly improved, and front suspension parts are no longer overstressed due to improper weight distribution.
Resumo:
El auge de las técnicas mecánicas, mediante rotación continua, en la preparación del sistema de conductos radiculares obliga a realizar una serie de reflexiones respecto a las ventajas e inconvenientes de las mismas según los diferentes objetivos que se persiguen en esta fase de la terapéutica. Se describe el sistema de instrumentación HERO 642 comparado con otras marcas y se expone la técnica propugnada por los diseñadores, Vulcain JM y Calas P, junto con las modificaciones propuestas por los autores del artículo. Finalmente, se establecen unas premisas fundamentales para el correcto empleo de la instrumentación rotatoria como técnica habitual en el tratamiento de conductos radiculares, en comparación con otros sistemas.
Resumo:
Interactions between zinc (Zn) and phosphate (Pi) nutrition in plants have long been recognized, but little information is available on their molecular bases and biological significance. This work aimed at examining the effects of Zn deficiency on Pi accumulation in Arabidopsis thaliana and uncovering genes involved in the Zn-Pi synergy. Wild-type plants as well as mutants affected in Pi signalling and transport genes, namely the transcription factor PHR1, the E2-conjugase PHO2, and the Pi exporter PHO1, were examined. Zn deficiency caused an increase in shoot Pi content in the wild type as well as in the pho2 mutant, but not in the phr1 or pho1 mutants. This indicated that PHR1 and PHO1 participate in the coregulation of Zn and Pi homeostasis. Zn deprivation had a very limited effect on transcript levels of Pi-starvation-responsive genes such as AT4, IPS1, and microRNA399, or on of members of the high-affinity Pi transporter family PHT1. Interestingly, one of the PHO1 homologues, PHO1;H3, was upregulated in response to Zn deficiency. The expression pattern of PHO1 and PHO1;H3 were similar, both being expressed in cells of the root vascular cylinder and both localized to the Golgi when expressed transiently in tobacco cells. When grown in Zn-free medium, pho1;h3 mutant plants displayed higher Pi contents in the shoots than wild-type plants. This was, however, not observed in a pho1 pho1;h3 double mutant, suggesting that PHO1;H3 restricts root-to-shoot Pi transfer requiring PHO1 function for Pi homeostasis in response to Zn deficiency.
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The IncP alpha promiscuous plasmid (R18, R68, RK2, RP1 and RP4) comprises 60,099 bp of nucleotide sequence, encoding at least 74 genes. About 40 kb of the genome, designated the IncP core and including all essential replication and transfer functions, can be aligned with equivalent sequences in the IncP beta plasmid R751. The compiled IncP alpha sequence revealed several previously unidentified reading frames that are potential genes. IncP alpha plasmids carry genetic information very efficiently: the coding sequences of the genes are closely packed but rarely overlap, and occupy almost 86% of the genome's nucleotide sequence. All of the 74 genes should be expressed, although there is as yet experimental evidence for expression of only 60 of them. Six examples of tandem-in-frame initiation sites specifying two gene products each are known. Two overlapping gene arrangements occupy different reading frames of the same region. Intergenic regions include most of the 25 promoters; transcripts are usually polycistronic. Translation of most of the open reading frames seems to be initiated independently, each from its own ribosomal binding and initiation site, although, a few cases of coupled translation have been reported. The most frequently used initiation codon is AUG but translation for a few open reading frames begins at GUG or UUG. The most common stop-codon is UGA followed by UAA and then UAG. Regulatory circuits are complex and largely dependent on two components of the central control operon. KorA and KorB are transcriptional repressors controlling at least seven operons. KorA and KorB act synergistically in several cases by recognizing and binding to conserved nucleotide sequences. Twelve KorB binding sites were found around the IncP alpha sequence and these are conserved in R751 (IncP beta) with respect to both sequence and location. Replication of IncP alpha plasmids requires oriV and the plasmid-encoded initiator protein TrfA in combination with the host-encoded replication machinery. Conjugative plasmid transfer depends on two separate regions occupying about half of the genome. The primary segregational stability system designated Par/Mrs consists of a putative site-specific recombinase, a possible partitioning apparatus and a post-segregational lethality mechanism, all encoded in two divergent operons. Proteins related to the products of F sop and P1 par partitioning genes are separately encoded in the central control operon.
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Photosynthetic responses to daily environmental changes were studied in bean (Phaseolus vulgaris L.) genotypes 'Carioca', 'Ouro Negro', and Guarumbé. Light response curves of CO2 assimilation and stomatal conductance (g s) were also evaluated under controlled (optimum) environmental condition. Under this condition, CO2 assimilation of 'Carioca' was not saturated at 2,000 µmol m-2 s-1, whereas Guarumbé and 'Ouro Negro' exhibited different levels of light saturation. All genotypes showed dynamic photoinhibition and reversible increase in the minimum chlorophyll fluorescence yield under natural condition, as well as lower photosynthetic capacity when compared with optimum environmental condition. Since differences in g s were not observed between natural and controlled conditions for Guarumbé and 'Ouro Negro', the lower photosynthetic capacity of these genotypes under natural condition seems to be caused by high temperature effects on biochemical reactions, as suggested by increased alternative electron sinks. The highest g s values of 'Carioca' were observed at controlled condition, providing evidences that reduction of photosynthetic capacity at natural condition was due to low g s in addition to the high temperature effects on the photosynthetic apparatus. 'Carioca' exhibited the highest photosynthetic rates under optimum environmental condition, and was more affected by daily changes of air temperature and leaf-to-air vapor pressure difference.
Resumo:
Reflective cracking in hot mix asphalt (HMA) overlays has been a common cause of poor pavement performance in Iowa for many years. Reflective cracks commonly occur in HMA overlays when deteriorated portland cement concrete is paved over with HMA. This results in HMA pavement surfaces with poor ride quality and increased transportation maintenance costs. To delay the formation of cracks in HMA overlays, the Iowa Department of Transportation (Iowa DOT) has begun to implement a crack-relief interlayer mix design specification. The crack-relief interlayer is an asphalt-rich, highly flexible HMA that can resist cracking in high strain loading conditions. In this project, the field performance of an HMA overlay using a one inch interlayer was compared to a conventional HMA overlay without an interlayer. Both test sections were constructed on US 169 in Adel, Iowa as part of an Iowa DOT overlay project. The laboratory performance of the interlayer mix design was assessed for resistance to cracking from repeated strains by using the four-point bending beam apparatus. An HMA using a highly polymer modified binder was designed and shown to meet the laboratory performance test criteria. The field performance of the overlay with the interlayer exceeded the performance of the conventional overlay that did not have the interlayer. After one winter season, 29 percent less reflective cracking was measured in the pavement section with the interlayer than the pavement section without the interlayer. The level of cracking severity was also reduced by using the interlayer in the overlay.
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Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone that potentiates glucose-induced insulin secretion by pancreatic beta cells. The mechanisms of interaction between GLP-1 and glucose signaling pathways are not well understood. Here we studied the coupling of the cloned GLP-1 receptor, expressed in fibroblasts or in COS cells, to intracellular second messengers and compared this signaling with that of the endogenous receptor expressed in insulinoma cell lines. Binding of GLP-1 to the cloned receptor stimulated formation of cAMP with the same dose dependence and similar kinetics, compared with the endogenous receptor of insulinoma cells. Compared with forskolin-induced cAMP accumulation, that induced by GLP-1 proceeded with the same initial kinetics but rapidly reached a plateau, suggesting fast desensitization of the receptor. Coupling to the phospholipase C pathway was assessed by measuring inositol phosphate production and variations in the intracellular calcium concentration. No GLP-1-induced production of inositol phosphates could be measured in the different cell types studied. A rise in the intracellular calcium concentration was nevertheless observed in transfected COS cells but was much smaller than that observed in response to norepinephrine in cells also expressing the alpha 1B-adrenergic receptor. Importantly, no such increase in the intracellular calcium concentration could be observed in transfected fibroblasts or insulinoma cells, which, however, responded well to thrombin or carbachol, respectively. Together, our data show that interaction between GLP-1 and glucose signaling pathways in beta cells may be mediated uniquely by an increase in the intracellular cAMP concentration, with the consequent activation of protein kinase A and phosphorylation of elements of the glucose-sensing apparatus or of the insulin granule exocytic machinery.
Effect of Delay in Testing Asphalt Concrete Specimens for Marshall Stability, MLR-86-08, Draft, 1986
Resumo:
The Central Laboratory has been delaying the mix design testing of 2 1/2" X 4" Marshall specimens for stability, until the next day after molding. For example, if the mixes are made and samples molded on Friday a man would have to come in and work on Saturday to test these specimens. The reason for this is that the ASTM-01559 "Resistance to Plastic Flow of Bituminous Mixes Using Marshall Apparatus," states that "the specimens after being molded shall be carefully transferred to a smooth, flat surface and allowed to stand overnight at room temperature, before being weighed, measured and tested." The AASHTO procedure, AASHTO Designation T-245-82 "Resistance to Plastic Flow of Bituminous Mixtures using Marshall Apparatus," does not say when the specimens shall be tested for stability. The IDOT Lab. Specifications, Test Method No. Iowa 502-8 and test method No. Iowa 506-C "compacting asphaltic concrete by the Marshall Method" and "Resistance to Plastic Flow of Bituminous Mixtures Using the Marshall Apparatus," respectively, only state that the specimens shall be cooled before testing. Due to the above conflict in specifications, a number of mix samples were tested, in the Central Lab, for stability on different days. This should furnish enough information to allow us to change the procedure and to test for stability the same day molded, or be able to delay the testing for 3 days or more.
Resumo:
The purpose of this study was to evaluate the efficacy of a Coulomb Controlled Iontophoresis system (CCI) in the local delivery of corticosteroids for the treatment of uveitis. The therapeutic efficacy of Dexamethasone (Dex) administered by CCI was compared to systemic injection and to topical application with the iontophoresis apparatus in the absence of electrical current. The evaluation was done in the treatment of the endotoxin-induced uveitis (EIU) model, and in the effect on TNF gene expression in the iris/ciliary body as well as in the retina and on TNF levels in aqueous humor and vitreous. Dex was administered either at the time of LPS injection or 5 hours later. For iontophoresis, we used a 1 ml reservoir-electrode covering the cornea, the limbus, and the first millimeter of the sclera. The applied electrical current was of 400 microA during four minutes with a total surface charge of 0.4 C cm-2. EIU was evaluated by clinical examination, by counts of intraocular inflammatory cells on histological sections, and by measuring the protein levels in the aqueous humor and in the vitreous. The TNF-alpha gene expression in the iris and ciliary body, and in the retina was evaluated by RT-PCR. The systemic effect of Dex delivered by CCI was evaluated on the level of serum TNF-alpha in EIU. Our results demonstrated that local administration of Dex by CCI inhibited anterior and posterior signs of intraocular inflammation as effectively as systemic administration, with no effect on systemic level of TNF. In the anterior and posterior segments of the eye, the protein exudation. TNF levels and the cellular infiltration were inhibited. The TNF-alpha gene expression was inhibited in the anterior as well as the posterior segment of the eye. No clinical nor histological damage were caused by the CCI apparatus. In conclusion, CCI administration of Dex allows for a therapeutic effect on the posterior as well as the anterior segment of the eye, and may present a viable alternative to systemic administration of glucocorticoids in severe ocular inflammations.