962 resultados para Current Control


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background: Quality control procedures vary considerably among the providers of equipment for home mechanical ventilation (HMV). Methods: A multicentre quality control survey of HMV was performed at the home of 300 patients included in the HMV programmes of four hospitals in Barcelona. It consisted of three steps: (1) the prescribed ventilation settings, the actual settings in the ventilator control panel, and the actual performance of the ventilator measured at home were compared; (2) the different ventilator alarms were tested; and (3) the effect of differences between the prescribed settings and the actual performance of the ventilator on non-programmed readmissions of the patient was determined. Results: Considerable differences were found between actual, set, and prescribed values of ventilator variables; these differences were similar in volume and pressure preset ventilators. The percentage of patients with a discrepancy between the prescribed and actual measured main ventilator variable (minute ventilation or inspiratory pressure) of more than 20% and 30% was 13% and 4%, respectively. The number of ventilators with built in alarms for power off, disconnection, or obstruction was 225, 280 and 157, respectively. These alarms did not work in two (0.9%), 52 (18.6%) and eight (5.1%) ventilators, respectively. The number of non-programmed hospital readmissions in the year before the study did not correlate with the index of ventilator error. Conclusions: This study illustrates the current limitations of the quality control of HMV and suggests that improvements should be made to ensure adequate ventilator settings and correct ventilator performance and ventilator alarm operation.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In 1980 the World Health Organization declared that smallpox was eradicated from the world, and routine smallpox vaccination was discontinued. Nevertheless, samples of the smallpox virus (variola virus) were retained for research purposes, not least because of fears that terrorist groups or rogue states might also have kept samples in order to develop a bioweapon. Variola virus represents an effective bioweapon because it is associated with high morbidity and mortality and is highly contagious. Since September 11, 2001, countries around the world have begun to develop policies and preparedness programs to deal with a bioterror attack, including stockpiling of smallpox vaccine. Smallpox vaccine itself may be associated with a number of serious adverse events, which can often be managed with vaccinia immune globulin (VIG). VIG may also be needed as prophylaxis in patients for whom pre-exposure smallpox vaccine is contraindicated (such as those with eczema or pregnant women), although it is currently not licensed in these cases. Two intravenous formulations of VIG (VIGIV Cangene and VIGIV Dynport) have been licensed by the FDA for the management of patients with progressive vaccinia, eczema vaccinatum, severe generalized vaccinia, and extensive body surface involvement or periocular implantation following inadvertent inoculation.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Only limited data is available on the relationship between family history of laryngeal and other neoplasms and laryngeal cancer risk. We investigated the issue using data from a multicentre case-control study conducted in Italy and Switzerland between 1992 and 2009 including 852 cases with histologically confirmed laryngeal cancer and 1970 controls admitted to hospital for acute, non neoplastic conditions. Unconditional logistic regression models adjusted for age, sex, study center, education, tobacco smoking, alcohol drinking and number of siblings were used to estimate the odds ratios (ORs) of laryngeal cancer. The multivariate OR was 2.8 (95% confidence interval [CI], 1.5-5.3) in subjects reporting a first-degree relative with laryngeal cancer, as compared to subjects with no family history. The OR was higher when the relative was diagnosed before 60 years of age (OR = 3.5, 95% CI 1.4-8.8). As compared to subjects without family history, non-smokers, and moderate drinkers, the OR was 37.1 (95% CI 9.9-139.4) for current smokers, heavy drinkers, with family history of laryngeal cancer. Family history of colorectal (OR = 1.5, 95% CI 1.0-2.3) and kidney (OR = 3.8, 95% CI 1.2-12.1) cancer were also associated to an increased risk of laryngeal cancer, while no significant increase in risk was found for family history of cancer at all sites, excluding the larynx (OR = 1.1).

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The Gp-9 gene in fire ants represents an important model system for studying the evolution of social organization in insects as well as a rich source of information relevant to other major evolutionary topics. An important feature of this system is that polymorphism in social organization is completely associated with allelic variation at Gp-9, such that single-queen colonies (monogyne form) include only inhabitants bearing B-like alleles while multiple-queen colonies (polygyne form) additionally include inhabitants bearing b-like alleles. A recent study of this system by Leal and Ishida (2008) made two major claims, the validity and significance of which we examine here. After reviewing existing literature, analyzing the methods and results of Leal and Ishida (2008), and generating new data from one of their study sites, we conclude that their claim that polygyny can occur in Solenopsis invicta in the U.S.A. in the absence of expression of the b-like allele Gp-9(b) is unfounded. Moreover, we argue that available information on insect OBPs (the family of proteins to which GP-9 belongs), on the evolutionary/population genetics of Gp-9, and on pheromonal/behavioral control of fire ant colony queen number fails to support their view that GP-9 plays no role in the chemosensory-mediated communication that underpins regulation of social organization. Our analyses lead us to conclude that there are no new reasons to question the existing consensus view of the Gp-9 system outlined in Gotzek and Ross (2007).

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The emergence of powerful new technologies, the existence of large quantities of data, and increasing demands for the extraction of added value from these technologies and data have created a number of significant challenges for those charged with both corporate and information technology management. The possibilities are great, the expectations high, and the risks significant. Organisations seeking to employ cloud technologies and exploit the value of the data to which they have access, be this in the form of "Big Data" available from different external sources or data held within the organisation, in structured or unstructured formats, need to understand the risks involved in such activities. Data owners have responsibilities towards the subjects of the data and must also, frequently, demonstrate that they are in compliance with current standards, laws and regulations. This thesis sets out to explore the nature of the technologies that organisations might utilise, identify the most pertinent constraints and risks, and propose a framework for the management of data from discovery to external hosting that will allow the most significant risks to be managed through the definition, implementation, and performance of appropriate internal control activities.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The multiscale finite-volume (MSFV) method is designed to reduce the computational cost of elliptic and parabolic problems with highly heterogeneous anisotropic coefficients. The reduction is achieved by splitting the original global problem into a set of local problems (with approximate local boundary conditions) coupled by a coarse global problem. It has been shown recently that the numerical errors in MSFV results can be reduced systematically with an iterative procedure that provides a conservative velocity field after any iteration step. The iterative MSFV (i-MSFV) method can be obtained with an improved (smoothed) multiscale solution to enhance the localization conditions, with a Krylov subspace method [e.g., the generalized-minimal-residual (GMRES) algorithm] preconditioned by the MSFV system, or with a combination of both. In a multiphase-flow system, a balance between accuracy and computational efficiency should be achieved by finding a minimum number of i-MSFV iterations (on pressure), which is necessary to achieve the desired accuracy in the saturation solution. In this work, we extend the i-MSFV method to sequential implicit simulation of time-dependent problems. To control the error of the coupled saturation/pressure system, we analyze the transport error caused by an approximate velocity field. We then propose an error-control strategy on the basis of the residual of the pressure equation. At the beginning of simulation, the pressure solution is iterated until a specified accuracy is achieved. To minimize the number of iterations in a multiphase-flow problem, the solution at the previous timestep is used to improve the localization assumption at the current timestep. Additional iterations are used only when the residual becomes larger than a specified threshold value. Numerical results show that only a few iterations on average are necessary to improve the MSFV results significantly, even for very challenging problems. Therefore, the proposed adaptive strategy yields efficient and accurate simulation of multiphase flow in heterogeneous porous media.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The mammalian brain oscillates through three distinct global activity states: wakefulness, non-rapid eye movement (NREM) sleep and REM sleep. The regulation and function of these 'vigilance' or 'behavioural' states can be investigated over a broad range of temporal and spatial scales and at different levels of functional organization, i.e. from gene expression to memory, in single neurons, cortical columns or the whole brain and organism. We summarize some basic questions that have arisen from recent approaches in the quest for the functions of sleep. Whereas traditionally sleep was viewed to be regulated through top-down control mechanisms, recent approaches have emphasized that sleep is emerging locally and regulated in a use-dependent (homeostatic) manner. Traditional markers of sleep homeostasis, such as the electroencephalogram slow-wave activity, have been linked to changes in connectivity and plasticity in local neuronal networks. Thus waking experience-induced local network changes may be sensed by the sleep homeostatic process and used to mediate sleep-dependent events, benefiting network stabilization and memory consolidation. Although many questions remain unanswered, the available data suggest that sleep function will best be understood by an analysis which integrates sleep's many functional levels with its local homeostatic regulation.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

BACKGROUND: We reviewed the current evidence on the benefit and harm of pre-hospital tracheal intubation and mechanical ventilation after traumatic brain injury (TBI). METHODS: We conducted a systematic literature search up to December 2007 without language restriction to identify interventional and observational studies comparing pre-hospital intubation with other airway management (e.g. bag-valve-mask or oxygen administration) in patients with TBI. Information on study design, population, interventions, and outcomes was abstracted by two investigators and cross-checked by two others. Seventeen studies were included with data for 15,335 patients collected from 1985 to 2004. There were 12 retrospective analyses of trauma registries or hospital databases, three cohort studies, one case-control study, and one controlled trial. Using Brain Trauma Foundation classification of evidence, there were 14 class 3 studies, three class 2 studies, and no class 1 study. Six studies were of adults, five of children, and three of both; age groups were unclear in three studies. Maximum follow-up was up to 6 months or hospital discharge. RESULTS: In 13 studies, the unadjusted odds ratios (ORs) for an effect of pre-hospital intubation on in-hospital mortality ranged from 0.17 (favouring control interventions) to 2.43 (favouring pre-hospital intubation); adjusted ORs ranged from 0.24 to 1.42. Estimates for functional outcomes after TBI were equivocal. Three studies indicated higher risk of pneumonia associated with pre-hospital (when compared with in-hospital) intubation. CONCLUSIONS: Overall, the available evidence did not support any benefit from pre-hospital intubation and mechanical ventilation after TBI. Additional arguments need to be taken into account, including medical and procedural aspects.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Transportation agencies in Iowa are responsible for a significant public investment with the installation and maintenance of traffic control devices and pavement markings. Included in this investment are thousands of signs and other inventory items, equipment, facilities, and staff. The proper application of traffic control devices and pavement markings is critical to public safety on streets and highways, and local governments have a prescribed responsibility under the Code of Iowa to properly manage these assets. This research report addresses current traffic control and pavement marking application, maintenance, and management in Iowa.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The circadian timekeeping mechanism adapts physiology to the 24-hour light/dark cycle. However, how the outputs of the circadian clock in different peripheral tissues communicate and synchronize each other is still not fully understood. The circadian clock has been implicated in the regulation of numerous processes, including metabolism, the cell cycle, cell differentiation, immune responses, redox homeostasis, and tissue repair. Accordingly, perturbation of the machinery that generates circadian rhythms is associated with metabolic disorders, premature ageing, and various diseases including cancer. Importantly, it is now possible to target circadian rhythms through systemic or local delivery of time cues or compounds. Here, we summarize recent findings in peripheral tissues that link the circadian clock machinery to tissue-specific functions and diseases.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The major problems associated with the use of corticosteroids for the treatment of ocular diseases are their poor intraocular penetration to the posterior segment when administered locally and their secondary side effects when given systemically. To circumvent these problems more efficient methods and techniques of local delivery are being developed. The purposes of this study were: (1) to investigate the pharmacokinetics of intraocular penetration of hemisuccinate methyl prednisolone (HMP) after its delivery using the transscleral Coulomb controlled iontophoresis (CCI) system applied to the eye or after intravenous (i.v.) injection in the rabbit, (2) to test the safety of the CCI system for the treated eyes and (3) to compare the pharmacokinetic profiles of HMP intraocular distribution after CCI delivery to i.v. injection. For each parameter evaluated, six rabbit eyes were used. For the CCI system, two concentrations of HMP (62.5 and 150mg ml(-1)), various intensities of current and duration of treatment were analyzed. In rabbits serving as controls the HMP was infused in the CCI device but without applied electric current. For the i.v. delivery, HMP at 10mg kg(-1)as a 62.5mg ml(-1)solution was used. The rabbits were observed clinically for evidence of ocular toxicity. At various time points after the administration of drug, rabbits were killed and intraocular fluids and tissues were sampled for methylprednisolone (MP) concentrations by high pressure liquid chromatography (HPLC). Histology examinations were performed on six eyes of each group. Among groups that received CCI, the concentrations of MP increased in all ocular tissues and fluids in relation to the intensities of current used (0.4, 1.0 and 2.0mA/0.5cm(2)) and its duration (4 and 10min). Sustained and highest levels of MP were achieved in the choroid and the retina of rabbit eyes treated with the highest current and 10min duration of CCI. No clinical toxicity or histological lesions were observed following CCI. Negligible amounts of MP were found in ocular tissues in the CCI control group without application of current. Compared to i.v. administration, CCI achieved higher and more sustained tissue concentrations with negligible systemic absorption. These data demonstrate that high levels of MP can be safely achieved in intraocular tissues and fluids of the rabbit eye, using CCI. With this system, intraocular tissues levels of MP are higher than those achieved after i.v. injection. Furthermore, if needed, the drug levels achieved with CCI can be modulated as a function of current intensity and duration of treatment. CCI could therefore be used as an alternative method for the delivery of high levels of MP to the intraocular tissues of both the anterior and posterior segments.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The current shortage of highway funds precludes the immediate replacement of most of the bridges that have been evaluated as structurally deficient or functionally obsolete or both. A low water stream crossing (LWSC) affords an economical alternative to the replacement of a bridge with another bridge in many instances. However, the potential liability that might be incurred from the use of LWSCs has served as a deterrent to their use. Nor have guidelines for traffic control devices been developed for specific application to LWSCs. This research addressed the problems of liability and traffic control associated with the use of LWSCs. Input to the findings from this research was provided by several persons contacted by telephone plus 189 persons who responded to a questionnaire concerning their experience with LWSCs. It was concluded from this research that a significant potential for accidents and liability claims could result from the use of LWSCs. However, it was also concluded that this liability could be reduced to within acceptable limits if adequate warning of the presence of an LWSC were afforded to road users. The potential for accidents and liability could further be reduced if vehicular passage over an LWSC were precluded during periods when the road was flooded. Under these conditions, it is believed, the potential for liability from the use of an LWSC on an unpaved, rural road would be even less than that resulting from the continuing use of an inadequate bridge. The signs recommended for use in advance of an LWSC include two warning signs and one regulatory sign with legends as follows: FLOOD AREA AHEAD, IMPASSABLE DURING HIGH WATER, DO NOT ENTER WHEN FLOODED. Use of the regulatory sign would require an appropriate resolution by the Board of Supervisors having responsibility for a county road. Other recommendations include the optional use of either a supple mental distance advisory plate or an advisory speed plate, or both, under circumstances where these may be needed. It was also recommended HR-218 Liability & Traffic Control Considerations for Low Water Stream Crossings that LWSCs be used only on unpaved roads and that they not be used in locations where flooding of an LWSC would deprive dwelling places of emergency ground access.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The impact of host genetic variation on determining the differential outcomes after HIV infection has been studied by two approaches: targeting of candidate genes and genome-wide association studies (GWASs). The overlap in genetic variants that has been identified by these two means has essentially been restricted to variants near to the human leukocyte antigen (HLA) class I genes, although variation in the CCR5 locus, which was first shown to have an effect on HIV outcomes using the candidate gene approach, does reach significance genome-wide when very large samples sizes (i.e. thousands) are used in GWAS. Overall, many of the variants identified by the candidate gene approach are likely to be spurious, as no additional variants apart from a novel variant near the HLA-C gene have been consistently identified by GWAS. Variants with low frequency and/or low impact on HIV outcomes are likely to exist in the genome and there could be many of them, but these are not identifiable, given current GWAS sample sizes. Several loci centrally involved in the immune response, including the immunoglobulin genes, T-cell receptor loci, or leukocyte receptor complex, are either poorly covered on the GWAS chips or difficult to interpret due to their repetitive nature and/or the presence of insertion/deletion polymorphisms in the region. These loci warrant further interrogation, but genetic characterization of these regions across a range of individuals will first be required. Finally, synergistic interactions between loci may affect outcome after infection, as suggested by associations of specific, functionally relevant HLA and killer cell immunoglobulin-like receptor variants with HIV disease outcomes, and these require further consideration as well.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This report describes a new approach to the problem of scheduling highway construction type projects. The technique can accurately model linear activities and identify the controlling activity path on a linear schedule. Current scheduling practices are unable to accomplish these two tasks with any accuracy for linear activities, leaving planners and manager suspicious of the information they provide. Basic linear scheduling is not a new technique, and many attempts have been made to apply it to various types of work in the past. However, the technique has never been widely used because of the lack of an analytical approach to activity relationships and development of an analytical approach to determining controlling activities. The Linear Scheduling Model (LSM) developed in this report, completes the linear scheduling technique by adding to linear scheduling all of the analytical capabilities, including computer applications, present in CPM scheduling today. The LSM has tremendous potential, and will likely have a significant impact on the way linear construction is scheduled in the future.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

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.