SEARCH · Search PubMed

Results for “Functional verification”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources

PubMed1976

The allosteric effect of inositol hexasulfate on oxygen binding by hemoglobin.

Myoinositol hexasulfate (IHS) is a powerful allosteric effector of oxygen binding by hemoglobin. It binds to deoxyhemoglobin at the same site as 2,3-diphosphoglycerate (DPG) and inositol hexaphosphate (IHP) with an affinity which is intermediate between that of the two phosphate esters. The binding constant calculated from the displacement of the oxygenation curve in the presence of low concentrations of IHS is 0.9X10(6) M. The value obtained directly from the number of protons bound as a function of IHS concentration is 1.0X10(6) M. The agreement between these two independent measurements provides an experimental verification of the empirical equation, relating the oxygen affinity to the binding constants, proposed previously (Benesch, R.E., Benesch, R., Renthal, R and Gratzer, W.B. (1971), Nature (London), New Biol. 2348 174).

Binding Sites↗

PubMedDate not supplied

Validation: the new challenge for pathology.

Modern pathologists have been challenged to "validate" mouse models of human cancer. Validation requires matching of morphological attributes of the model to human disease. Computers can assist in the validation process. However, adequate controlled, computer-readable vocabularies that can match terms do not currently exist in mouse pathology. Further, current standard diagnostic terminologies do not include the new concepts discussed here such as pathway pathology and mammary intraepithelial neoplasia. The terminologies must be revised and improved to meet the challenge. Human medicine has traditionally used "guilt-by-association" to validate interpretations of disease. Experimental pathology uses experimental verification exemplified by "test-by-transplantation." Genetically Engineered Mice (GEM) develop unique tumor phenotypes bringing new structural-functional insights and reevaluation of concepts. Novel GEM-related tumors appear in all organ systems but mouse models of human breast cancer are prototypes. For example, mammary tumors induced by Mouse Mammary Tumor Virus (MMTV), chemical, radiation or other carcinogenic stimuli have limited phenotypes. These "spontaneous" or induced mammary tumors have never resembled human breast cancers. GEM tumors created with genes associated with human cancer are strikingly different. GEM tumors have unique histological phenotypes. Depending on the genes, the tumors may: 1) resemble MMTV-induced tumors, 2) display "signature" phenotypes, and 3) mimic human breast cancers. The phenotypes can be placed into structural and functional clusters with shared characteristics leading to the concepts of Pathway Pathology: tumor phenotype reflects the genotype.

Animals↗

PubMed2002

Particle image velocimetry and thermometry for two-phase flow problems.

Image processing in fluid mechanics has become an important quantitative tool for flow analysis. The feasibility of simultaneous measurements of instantaneous velocity and temperature fields, as well as for tracking interfaces, creates a functional tool to describe thermally driven flows accompanied by phase change. The information thus gathered is essential for the verification and validation of computation models. The paper reviews the image processing methods developed by the author and his coworkers to analyze typical problems of two-phase flow. Simultaneous measurement of temperature and velocity fields, obtained by using liquid crystal tracers, are applied to elucidate solidification and growing vapor bubble problems.

Convection↗

PubMed2006

Multifactor authentication reinforces optical security.

A new optical method to obtain multifactor image encoding and authentication is proposed. The encoded complex-amplitude image function fulfills the general requirements of invisible content, extreme difficulty in copying or counterfeiting, and real-time automatic verification. This optical technique is attractive for high-security purposes that require multifactor reliable authentication. A demonstration using a combination of biometric images and key codes is provided. Retina images, which are very effective for authentication, are used as biometric signals. To the best of our knowledge, this is the first report on combined multiple signal encoding and simultaneous AND authentications for optical security reinforcement.

Journal Article↗

PubMed2006

Neural Query System: Data-mining from within the NEURON simulator.

We have developed a simulation tool within the NEURON simulator to assist in organization, verification, and analysis of simulations. This tool, denominated Neural Query System (NQS), provides a relational database system, a query function based on the SELECT function of Structured Query Language, and data-mining tools. We show how NQS can be used to organize, manage, verify, and visualize parameters for both single cell and network simulations. We demonstrate an additional use of NQS to organize simulation output and relate outputs to parameters in a network model. The NQS software package is available at http://senselab. med.yale.edu/senselab/SimToolDB.

Animals↗

PubMed2001

Risk management-an industry approach.

An effective risk management system covering the whole process of food production from "farm to fork" is required by the food industry in order to assure that the food provided to consumers is safe. Food safety and quality assurance begins with the design and development of food products starting with product conceptualisation and continuing with the selection, purchasing, and evaluation of raw materials and with the specifications for processing, packaging and distribution. Within a larger quality management framework a number of tools have been developed by the food industry, which when used in an integrated fashion facilitate the management of food safety. These include good manufacturing practice (GMP), good hygiene practice (GHP) and HACCP (hazard analysis critical control point) as well as quality systems which allow the verification that all factors affecting the safety of a product are under control. Finally, regulations and systems can only function if they are applied. Everyone, from the farmer, the line operator in the manufacturing plant, to the person handling the food in distribution and sales, needs to be aware of his influence with regards safety. The effectiveness of safety awareness programs specific to each area is key to an industry approach to risk management.

Agriculture↗

PubMed2003

Candida albicans response regulator gene SSK1 regulates a subset of genes whose functions are associated with cell wall biosynthesis and adaptation to oxidative stress.

Ssk1p of Candida albicans is a putative response regulator protein of the Hog1 two-component signal transduction system. In Saccharomyces cerevisiae, the phosphorylation state of Ssk1p determines whether genes that promote the adaptation of cells to osmotic stress are activated. We have previously shown that C. albicans SSK1 does not complement the ssk1 mutant of S. cerevisiae and that the ssk1 mutant of C. albicans is not sensitive to sorbitol. In this study, we show that the C. albicans ssk1 mutant is sensitive to several oxidants, including hydrogen peroxide, t-butyl hydroperoxide, menadione, and potassium superoxide when each is incorporated in yeast extract-peptone-dextrose (YPD) agar medium. We used DNA microarrays to identify genes whose regulation is affected by the ssk1 mutation. RNA from mutant cells (strain CSSK21) grown in YPD medium for 3 h at 30 degrees C was reverse transcribed and then compared with similarly prepared RNA from wild-type cells (CAF2). We observed seven genes from mutant cells that were consistently up regulated (three-fold or greater compared to CAF2). In S. cerevisiae, three (AHP1, HSP12, and PYC2) of the seven genes that were up regulated provide cells with an adaptation function in response to oxidative stress; another gene (GPH1) is regulated under stress conditions by Hog1p. Three other genes that are up regulated encode a cell surface protein (FLO1), a mannosyl transferase (MNN4-4), and a putative two-component histidine kinase (CHK1) that regulates cell wall biosynthesis in C. albicans. Of the down-regulated genes, ALS1 is a known cell adhesin in C. albicans. Verification of the microarray data was obtained by reverse transcription-PCR for HSP12, AHP1, CHK1, PYC2, GPH1, ALS1, MNN4-4, and FLO1. To further determine the function of Ssk1p in the Hog1p signal transduction pathway in C. albicans, we used Western blot analysis to measure phosphorylation of Hog1p in the ssk1 mutant of C. albicans when grown under either osmotic or oxidative stress. We observed that Hog1p was phosphorylated in the ssk1 mutant of C. albicans when grown in a hyperosmotic medium but was not phosphorylated in the ssk1 mutant when the latter was grown in the presence of hydrogen peroxide. These data indicate that C. albicans utilizes the Ssk1p response regulator protein to adapt cells to oxidative stress, while its role in the adaptation to osmotic stress is less certain. Further, SSK1 appears to have a regulatory function in some aspects of cell wall biosynthesis. Thus, the functions of C. albicans SSK1 differ from those of S. cerevisiae SSK1.

Adaptation, Physiological↗

PubMed2000

[Mechanisms of extreme states in human].

Pathogenesis of extreme states during hypoxic hypoxia, exogenic and combined hyperthermia, aerial and immersion hypothermia is mainly associated with deterioration of reactivity and decline of functional reserves of the neuroendocrinal system, energetic dysbalance against more pronounced signs of anaerobic catabolism and recruitment of plastic resources of the body, activation of peroxide oxidation of lipids (POL), depletion of AOS potential with labilization of cellular membranes, and progressing changes in structural and functional relations within the antigenous/structural homeostasis. The determinacy of extreme state is influenced by initial status of the body functioning. The bodily extreme state has been found to depend on severity of asthenisation, peculiarities of the autonomous regulation, metabolic and immune status. Partial or full reversibility of decompensation disorders distinguishes extreme state from the critical (predeterminal) one. The relative adequacy of compensation and the principal possibility of a beneficial result are the necessary conditions for extreme state verification. Otherwise, in the lack of time for effective compensation typical syndromes of critical states may develop already during acute adaptation. There can develop partial insufficiency of a dominating functional system which will be compensated at the sacrifice of other organs and tissues. Sometimes extreme state may result in development of marginal or pathological states with human living activities preserved.

Adaptation, Physiological↗

PubMedDate not supplied

[The value of double contrast arthrotomography combined with cinematography in the diagnosis of functional and structural TMJ alterations].

Double contrast arthrotomography combined with cinematography as a diagnostic instrument establishing functional and structural TMJ alterations is evaluated for its diagnostic value and reliability within the chain of diagnostic measures applied. In 131 patients double-contrast arthrotomography was followed by a comprehensive history of joint problems, and verification of the clinical findings as well as the arthrographic diagnosis and the post-arthrographic TMJ alterations. Our interest was focussed, among others, on the question whether arthrography alone would have any therapeutic effect or produce an alteration in TMJ function.

Adolescent↗

PubMed1991

An interleaved tracking procedure to monitor unstable psychometric functions.

In some experimental situations, the psychometric function underlying performance may not be stable, but instead may shift along the stimulus axis in response to changes in attention, learning, or task difficulty. When this occurs, the measured threshold may be influenced and the slope of the measured function will be inaccurately shallow. With commonly used experimental procedures, it is difficult to know whether a shallow psychometric function slope is a true reflection of the sensory process, or is a result of "averaging" a highly variable underlying function. Here, a new method is described of estimating psychometric function slope from the variability in two interleaved adaptive tracks, consulted on alternate trials, that is resistant to the effects of shifting performance levels. Further, a mechanism is described for assessing the likelihood that a threshold was, in fact, stable over the course of its measurement. Computer simulations are reported as well as verification of the method in measurements of human performance on a psychophysical task. Several conditions of externally imposed variability were simulated to establish the ability of these procedures to identify unstable functions and produce accurate slope estimates. The procedures worked well for thresholds shifting by as little as 4 dB if the variation did not occur too rapidly. The procedure and associated analyses are recommended as a relatively "free" means of calculating slope and quantifying threshold reliability with little extra experimental effort.

Attention↗

PubMed1996

A serial CT scan and MRI verification of diffuse cerebrospinal gliomatosis: a case report with stereotactic diagnosis and radiological confirmation.

Gliomatosis cerebri is an infrequent tumor of neuroepithelial origin presenting with deterioration of cognitive functions, behavioral and mental changes, motor weakness, headache, and seizures. Laboratory data are unconclusive. MRI appears to be the imaging modality of choice and mainly reveals a bilateral and diffuse infiltration of midline adjacent brain structures whose anatomical configuration remain intact. MRI- or CT-guided stereotactic biopsy is advised as the diagnostic procedure in suspected cases. A 9-year-old girl with diffuse cerebrospinal gliomatosis, investigated with sequential cranial CT scans, and MRI-verified spinal cord involvement is reported, and the corresponding literature is reviewed.

Biopsy↗

PubMed2002

[Overall design and proof-test of an integrated environmental control and life support system (ECLSS) for demonstration and verification].

Objective. To test and demonstrate embryonic form of our future space station ECLSS, which will also form an advanced research and test ground facility. Method. The following functions of the system were tested and demonstrated: integrated solid amine CO2 collection and concentration, Sabatier CO2 reduction, urine processing thermoelectric integrated membrane evaporation, solid polymer water electrolysis O2 generation, concentrated ventilation, temperature and humidity control, the measurement and control system, and other non-regenerative techniques. All of these were demonstrated in a sealed adiabatic module, and passed the proof-tests. Result. The principal technical requirements of the system and each regenerative subsystem were met. The integration of system general and each subsystem was successful, and the partial closed loop of the system's integration has been realized basically. Conclusion. The reasonableness of the project design was verified, and the major system technical requirements were satisfied. The suitability and harmonization among system general and each subsystem were good, the system operated normally, and the parameters measured were correct.

Amines↗

PubMed1977

[New aspects in diagnosis and therapy of placental insufficiency. Placental perfusion measurements; placental perfusion test (PPT) and betamimetic long term treatment (clinical and experimental data (authors transl)].

The rate of utero-placental blood flow depends on functional components (perfusion pressure and flow resistance within the area of the vascular bed of the placenta), as well as on morphological factors (regressive changes in the placenta). Different primary maternal conditions and diseases may lower the rate of placental flow, leading to placental insufficiency; the highest percentage, by far, of placental dysfunction is found in patients suffering from gestosis. Hypocirculation initially present in cases of EPH gestosis and caused by arteriolar spasms triggers off a vicious circle involving placental infarction and severe reduction in the utero-placental perfusion rate. This in turn leads to fetal hypotrophy, a high rate of premature births and perinatal mortality. Verification of HPL, HCG, alpha-Fetoprotein or E3 in maternal serum and amniotic fluid or urine greatly improved the recording of partial placental functions. Along with ultrasonic biometry, cardiotocography and amnioscopy, these hormonal parameters allow only indirect assessment of the placental function. On the other hand, measurements of the utero-placental flow offers a direct approach. In order to evaluate the placental flow measurements it is imperative to obtain a curve indicating the course over the last third of the pregnancy-in addition to establishing a general normal range. In case of placental insufficiency, it is necessary to determine whether this is due to functional disorders alone, or to more extenisve morphological changes. A placental perfusion test (PPT) was developed in order to make this distinction. Beta2-mimetic treatment is indicated if functional factors predominate, whereby it appears essential to obtain the requisite experimental data for precise quantification of beta-mimetic action.

Adrenergic beta-Agonists↗

PubMed2000

SPACR in the interphotoreceptor matrix of the mouse retina: molecular, biochemical and immunohistochemical characterization.

Mouse SPACR cDNA was cloned by screening a mouse retina cDNA library using a PCR probe derived from human SPACR cDNA. Mouse SPACR cDNA comprises 3675 bp containing an open reading frame coding for 742 amino acids. Multitissue Northern blot analysis and in situ hybridization studies indicate that SPACR expression is restricted to retinal photoreceptors. The SPACR core protein was identified with Western blotting following SDS-PAGE with a SPACR C-terminal peptide polyclonal antibody and a chondroitin-6-sulfate Deltadisaccharide monoclonal antibody. The 150 kD immunopositive band was isolated, digested with trypsin and the peptides analysed by MALDI mass spectroscopy. Peptide mass mapping confirmed the identity of the 150 kD immunopositive band to be mouse SPACR core protein. Alignment comparisons of the deduced amino acid sequence of mouse and human SPACR show 64% homology. Like SPACR in the human interphotoreceptor matrix, the mouse orthologue contains a large central mucin-like domain flanked by consensus sites for N-linked oligosaccharide attachment, one EGF-like domain and four hyaluronan-binding motifs. Unlike human SPACR, which contains no conventional consensus sites for glycosaminoglycan attachment, mouse SPACR contains three. Recent biochemical studies of human and mouse SPACR protein indicate that this novel interphotoreceptor matrix molecule is a glycoprotein in human and a proteoglycan in the mouse. The presence of consensus sites for glycosaminoglycan attachment in the deduced sequence of mouse SPACR and the absence of these sites in human SPACR provide molecular verification of our biochemical results, suggesting that differences in post-translational modifications of SPACR may be important in SPACR function in foveate and non-foveate retinas.

Amino Acid Sequence↗

PubMedDate not supplied

Long-term cognitive sequelae of solvent intoxication.

Memory problems lasting 8 months have previously been described for a small group of female solvent workers following an accidental workplace solvent intoxication. Three years after the intoxication the presence of longer-term residual impairment of cognitive functions was evaluated. The major residual difficulty uncovered related to the speed of processing linguistic material, with workers showing slower verification on tasks probing syntactic and semantic reasoning within the context of relatively unimpaired response execution speeds. Of particular interest was the intoxicated workers' difficulty with the conceptually more complex negative syntactic reasoning problems. This difficulty was also shared by solvent workers who were not involved in that accidental intoxication. In addition, decision fatigue was observed following prolonged responding in a continuous choice reaction time task, although ability to maintain vigilance and concentration were unaffected. Taken together, these findings indicate that a single solvent intoxication can give rise to long-term cognitive sequelae in solvent workers.

Adult↗

PubMed2006

Verification of antiparallel G-quadruplex structure in human telomeres by using two-photon excitation fluorescence lifetime imaging microscopy of the 3,6-Bis(1-methyl-4-vinylpyridinium)carbazole diiodide molecule.

Different G-quadruplex structures for the human telomeric sequence d(T2AG3)4 in vitro have been documented in the presence of sodium and potassium. Verification of the G-quadruplex structures in human telomeres in vivo is the main issue in establishing the biological function of the G-quadruplex structures in telomeres as well as the development of anticancer agents. Here we have applied two-photon excitation fluorescence lifetime imaging microscopy to measure the fluorescence lifetime of the BMVC molecule upon interaction with various DNA structures. The distinction in lifetime measured with submicrometer spatial resolution in two-photon excitation fluorescence lifetime imaging microscopy provides a powerful approach not only to verify the existence of the antiparallel G-quadruplex structure in human telomeres but also to map its localizations in metaphase chromosomes.

Carbazoles↗

PubMed2001

Cognitive skill acquisition and transfer in younger and older adults.

The acquisition of cognitive skills often depends on 1 of (or a combination of) 2 processes, the execution of an algorithm, and the retrieval of problem instances. This study examined the effects of age and repetition of problem instances on the production and verification of solutions to 2 serially presented sets of alphabet arithmetic problems. Analyses of the parameters derived from power-function fits for individuals revealed age differences favoring young adults in improvement span, learning rate, and asymptote. For both age groups, the beneficial effects of repetitions on 1st-set response times were attributable to algorithmic speedup and to the retrieval of instances, whereas improvements in the speed of 2nd-set response times were attributable primarily to item retrieval.

Adolescent↗

PubMedDate not supplied

Operational evaluation of pulse oximetry in NICU patients with arterial access.

OBJECTIVE: To investigate pulse oximetry in neonates who require arterial access as represented by the clinical data recorded to manage their care. STUDY DESIGN: Analysis of simultaneous SpO(2) and SaO(2) from: 7-year historical NICU data (N=31905); 4-month prospective NICU data (N=566); verification data using two hemoximeters (N=52); and NICU data from two collaborating centers (N=95 and 168). The bias function (SpO(2)-SaO(2)) was regressed against the measured "gold" standard, SaO(2). RESULTS: A significant negative correlation was found for each of the data sets between the bias function and SaO(2). This bias was similar for devices from several manufacturers (Datex-Ohmeda, Masimo, Nellcor, and Spacelabs). Maximum operational performance occurred with peaks between 92 and 97% SaO(2), but declined markedly above and below this narrow range. In all, 71 to 95% of patients exhibited data with significant bias(.) CONCLUSION: These operational data suggest that with the methodology and devices currently in use, SpO(2) values in most all neonates who require arterial lines inaccurately correlate with measured arterial saturation.

Cohort Studies↗