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Results for “Functional verification”

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At least 541 records · Page 30Linked to original sources
PubMed2001

Neurotization as an alternative for restoring finger and wrist extension.

OBJECT: In cases of irreparable injuries to the radial nerve or in cases in which nerves are repaired with little anticipation of restoration of function, tendon transfers are widely used. In this study, the authors searched for a more natural alternative for selectively restoring function, with the aid of a motor nerve transfer. METHODS: Ten arms from five cadavers were used in the study. The posterior interosseous nerve and the median nerve together with their motor branches were exposed in the proximal forearm. The possibility of posterior interosseous nerve neurotization via the median nerve through its motor branches leading to the pronator teres, flexor pollicis longus, flexor digitorum profundus, and pronator quadratus muscles was investigated. The lengths of the nerves from points of divergence and their widths were measured using calipers, and the means with standard deviations of all nerves were calculated. Motor branches to the pronator teres, flexor pollicis longus, and pronator quadratus muscles were found to be suitable for neurotization of the posterior interosseous nerve at different levels and in various combinations. The motor nerve extending to the flexor digitorum profundus muscle was too short to use for transfer. CONCLUSIONS: These results offer a suitable alternative to tendon transfer for restoring finger and wrist extension in cases of irreversible radial palsy. The second step would be clinical verification in appropriate cases.

Cadaver↗
PubMed2002

Speciation analysis of trace elements in the brains of individuals with Alzheimer's disease with special emphasis on metallothioneins.

A speciation analysis of protein-bound elements in the cytosol of human brain was achieved by size exclusion chromatographical separation of the biomolecules and on-line detection of the metal profiles in the eluate by hyphenated inductively coupled plasma-mass spectrometry. Post-mortem samples from Alzheimer's disease brains and from brains of a control group were investigated to elucidate changes in the trace element distribution during the pathological process. Special attention was paid to the metallothioneins (MT) - cysteine-rich, metal-binding proteins of low molecular weight, existing in several isoforms. The isoform MT-3 is found especially in the brain and has a growth inhibition function on neurons. The MT peaks were identified in the element profiles. For this purpose, the metal binding capability and the heat stability of MT were taken into consideration. For verification, a comparison with pure MT-3 was carried out and further biochemical and analytical methods were applied to the fractions of the chromatographical run. A comparison between Alzheimer's disease and control brains showed a significant difference concerning the MT-1/-2 and MT-3 metal levels, leading to the assumption that there were oxidative processes having taken place in the Alzheimer's brain samples.

Alzheimer Disease↗
PubMed2026

Integrated photoelectrocatalytic reduction and oxidation processes to achieve efficient degradation of fluoxetine in pharmaceutical wastewater.

Fluorinated organic compounds have been frequently detected in aquatic environments, with the widespread use of fluorinated drugs. The existing processes of urban sewage treatment plants are difficult to completely remove these pollutants containing the persistent C-F bonds. In this work, an integrated system of UV-activated sulfite and UV-assisted electrochemical oxidation was innovatively constructed for efficient degradation of fluoxetine. For the UV-activated sulfite unit system, when the sulfite dosage was 0.5 mmol/L and the initial pH was about 10, the defluorination efficiency of 5 mg/L fluoxetine wastewater under nitrogen atmosphere was about 98 %. Subsequently, the UV-assisted electrochemical oxidation unit system was employed to treat the reduced wastewater mentioned above. When the sodium chloride dosage was 25 mmol/L, the initial pH was about 5, and the current density was 30 mA/cm2, the total organic carbon (TOC) removal of the wastewater arrived at 65 %. Active species capture experiments and ESR tests confirmed that hydrated electrons, hydroxyl, and chlorine radicals were the main components for the efficient degradation of fluoxetine. According to the analysis of Fukui function and HPLC-MS, the degradation pathway of pollutants was proposed including defluorination and mineralization. Meanwhile, the toxicity of intermediates was predicted using the ECOSAR program. In addition, the verification test of actual wastewater treatment indicated that the defluorination and TOC removal efficiency of fluorouracil by the integrated system were similar to those for fluoxetine. This work provided a new approach for the efficient degradation of fluorinated organic pollutants in pharmaceutical wastewater.

Fluoxetine↗
PubMed2003

Response-monitoring dysfunction in aging and Alzheimer's disease: an event-related potential study.

Executive control is a broad-reaching function that includes response monitoring and is likely implemented in the frontal lobes. Age- and dementia-related changes in response-monitoring were assessed during a Picture-Name Verification Task, using response-synchronized event-related potential (ERP) markers of response monitoring: the centrally oriented error-related negativity (ERN); the smaller and more frontally-oriented correct-response negativity (CRN); and the positivity associated with errors (Pe), a marker of error awareness. These were recorded from 10 younger and 10 older healthy controls, as well as 12 Alzheimer's disease (AD) patients. Although the older and younger controls showed equivalent accuracy, error awareness (Pe), and relative ERN>CRN amplitude, aging was associated with slower behavioral responses and decreased ERN amplitude. Although dementia was associated with decreased accuracy, decreased ERN, and a loss of relative ERN>CRN amplitude, error awareness (Pe) remained somewhat intact in AD patients. In AD patients, CRN amplitude was affected by item certainty (assessed a week earlier), being larger to items that were idiosyncratically difficult for patients to name.

Adult↗
PubMed2002

Natural display mode for digital DICOM-conformant diagnostic imaging.

RATIONALE AND OBJECTIVES: The authors performed this study to investigate the verification of the contrast display properties defined by the digital imaging and communication in medicine (DICOM) PS (picture archiving and communication system [PACS] standard) 3.14-2001 gray-scale display function standard and their dependency on display luminance range and video signal bandwidth. MATERIALS AND METHODS: Contrast sensitivity and contrast linearity of DICOM-conformant displays were measured in just-noticeable differences (JNDs) on special perceptual contrast test patterns. Measurements were obtained six times at various display settings under dark room conditions. RESULTS: Display luminance range and video bandwidth had a significant effect on contrast perception. The perceptual promises of the standard could be established only with displays that were calibrated to a unity contrast resolution, at which the number of displayed intensity steps was equal to the number of perceivable contrast steps (JNDs). Such display conditions provide for visual perception information at the level of single-step contrast sensitivity and full-range contrast linearity. These "natural display" conditions also help minimize the Mach banding effects that otherwise reduce contrast sensitivity and contrast linearity. CONCLUSION: Most, if not all, conventionally used digital display modalities are driven with a contrast resolution larger than 1. Such conditions reduce contrast perception when compared with natural imaging conditions. The DICOM-conformant display conditions at unity contrast resolution were characterized as the "natural display" mode, and, thus, the authors a priori recommend them as being useful for making a primary diagnosis with PACS and teleradiology and as a standard for psychophysical research and performance measurements.

Contrast Sensitivity↗
PubMed2004

Combination of hyperbolic functions for multimodal biometrics data fusion.

In this paper, we treat the problem of combining fingerprint and speech biometric decisions as a classifier fusion problem. By exploiting the specialist capabilities of each classifier, a combined classifier may yield results which would not be possible in a single classifier. The Feedforward Neural Network provides a natural choice for such data fusion as it has been shown to be a universal approximator. However, the training process remains much to be a trial-and-error effort since no learning algorithm can guarantee convergence to optimal solution within finite iterations. In this work, we propose a network model to generate different combinations of the hyperbolic functions to achieve some approximation and classification properties. This is to circumvent the iterative training problem as seen in neural networks learning. In many decision data fusion applications, since individual classifiers or estimators to be combined would have attained a certain level of classification or approximation accuracy, this hyperbolic functions network can be used to combine these classifiers taking their decision outputs as the inputs to the network. The proposed hyperbolic functions network model is first applied to a function approximation problem to illustrate its approximation capability. This is followed by some case studies on pattern classification problems. The model is finally applied to combine the fingerprint and speaker verification decisions which show either better or comparable results with respect to several commonly used methods.

Algorithms↗
PubMed1998

A contextually relevant assessment of the impact of child maltreatment on the social competencies of low-income urban children.

OBJECTIVE: A developmental-ecological model was used to explore the psychological adjustment and peer social competencies of maltreated preschool children. METHOD: Enhanced research methods were used that included verification of maltreatment status, multiple-variable matching of comparison children, and contextually relevant assessment. One hundred eight Head Start children, of whom 54 were maltreated, participated. Assessment of social functioning included measurement of peer play interactions, global social skills, peer sociometrics, and teacher and parent ratings of behavior problems. RESULTS: Findings indicated that maltreated children were significantly less interactive in peer play and overall exhibited less self-control and interpersonal skill in social interactions than nonmaltreated children. In addition, maltreated children were more likely than their nonmaltreated peers to receive low sociometric ratings and were found by both teachers and parents to display more internalizing behavior problems than comparison children. CONCLUSIONS: These findings indicate the importance of using developmentally sensitive research methods to inform contextually relevant interventions.

Case-Control Studies↗
PubMed2003

Numerical simulation and experimental verification of particle coagulation dynamics for a pulsed input.

Mathematical simulation of particle coagulation dynamics was carried out using improved sectional modeling techniques for a system with a pulsed input of primary particles. The methodological improvement included the modification of the size density function based on a realistic assumption of particle size distributions, the application of a new and comprehensive curvilinear collision model, and special adjustment for the mass transfer of a doublet of particles that were very different in size. The simulation results demonstrated that the rectilinear model over-predicted the rate of particle coagulation and that the degree of over-prediction increased as the particles increased in size and the system became more heterogeneous. The coagulation rate increased remarkably as the fractal dimension of the particle aggregates decreased. The curvilinear model and the fractal scaling relationship in place of the rectilinear model and the Euclidean sizing geometry are two important modifications to the conventional Smoluchowski modeling approach. However, both modifications, rather than only one of them, should be applied together to produce more accurate and realistic simulations of coagulation dynamics. As indicated by the simulation, the importance of fluid shear rate to particle coagulation is reduced according to the curvilinear model compared to that previously described with the rectilinear model. As particles increased in size, the role of shear rate in coagulation became even less significant according to the curvilinear view of particle collisions. The results of numerical simulations in terms of the evolution of particle size distributions compared reasonably well with the observations of the jar-test coagulation experiments, which suggested the applicability of the modeling system, including the modified curvilinear-fractal approach, established in the present study.

Computer Simulation↗
PubMedDate not supplied

Enteral feedings with comfort and safety.

Patients who are unable to eat by mouth can be fed in a manner that maintains the structural and functional integrity of the gastrointestinal tract. The appropriate choice of type of feeding tube to use is based on the reasons patients need to be tube fed and the expected duration of need for the tube. Once the tubes are placed, verification of placement is critical for safe use. Patients, family caregivers, and staff must assess for potential complications. Misplacement is the most common problem of feeding tubes. Life-threatening complications can include "refeed syndrome" and "buried bumper syndrome." Additional threats include contaminated tube feeding and inappropriate medication administration. Feeding too rapidly into the small intestine can cause necrosis of the small bowel. To maintain patient comfort, site care is critical. Nasogastric tubes can cause permanent deformity of the nares. Gastric drainage on the skin can cause painful excoriation that is difficult to manage. With careful monitoring of tube feedings, positive nutritional status can be achieved. A positive nutritional status assists in promoting health and immune function.

Enteral Nutrition↗
PubMed1975

[Cytologic diagnosis of different histologic forms of lung cancer].

Parallel cytological and histological investigations in 511 patients with of the lung cancer confirmed the possibility of verification of a tumour form on the basis of cytological preparations. Determination of cancer forms is carried out on the basis of the same principle criteria which are used in a histological investigation. The first stage of diagnosis consists in search for cellular, structural and functional signs of epidermoid and glandular differentiation. In the absence of these, there are grounds to consider the diagnosis to be non-differentiated cancer with subdivisions into micro- and macrocellular variants. Squamous-cell carcinoma with cornification highly differentiated adenocarcinoma and non-differentiated microcellular cancer possess characteristic features ensuring a highly reliable-cytological diagnosis. Cytological diagnosis of squamous-cell cancer was correct in 95.3% of cases, that of non-differentiated microcellular cancer-in 87.1%, and that of glandular cancer-in 81.2% of cases. The majority of errors made in verification of squamous-cell and glandular cancer were made with respect to their poorly differentiated forms which have no reliable cytological characteristics. The last statement is also true with respect to non-differentiated macrocellular cancer of the lung.

Adenocarcinoma↗
PubMed2005

Building a human kinase gene repository: bioinformatics, molecular cloning, and functional validation.

Kinases catalyze the phosphorylation of proteins, lipids, sugars, nucleosides, and other important cellular metabolites and play key regulatory roles in all aspects of eukaryotic cell physiology. Here, we describe the mining of public databases to collect the sequence information of all identified human kinase genes and the cloning of the corresponding ORFs. We identified 663 genes, 511 encoding protein kinases, and 152 encoding nonprotein kinases. We describe the successful cloning and sequence verification of 270 of these genes. Subcloning of this gene set in mammalian expression vectors and their use in high-throughput cell-based screens allowed the validation of the clones at the level of expression and the identification of previously uncharacterized modulators of the survivin promoter. Moreover, expressions of the kinase genes in bacteria, followed by autophosphorylation assays, identified 21 protein kinases that showed autocatalytic activity. The work described here will facilitate the functional assaying of this important gene family in phenotypic screens and their use in biochemical and structural studies.

Animals↗
PubMed2000

Cloning and functional analysis of cDNA encoding the hamster Bcl-2 protein.

We have cloned cDNA encoding hamster Bcl-2 protein from total RNA of CHO-9 cells by RT-PCR using oligonucleotide primers sharing homology with the sequence of mouse and rat bcl-2. The fragments spanning the total coding region were cloned into pCR4-TOPO and sequenced for verification. The hamster bcl-2 cDNA has a size of 711 nucleotides and encodes a polypeptide of 236 amino acids. Hamster Bcl-2 shares 95.8 and 88.6% similarity with mouse and human Bcl-2, respectively. Northern blot analysis revealed a single 7.5 kb bcl-2 transcript in hamster (CHO-9), mouse (BK4), and rat (H5) cells and a 8.5 kb bcl-2 mRNA in human (HeLa MR) cells. The bcl-2 cDNA (771 bp) was recloned into pcDNA3 and the recombinant construct was transiently transfected into MGMT-deficient HeLa MR cells. Expression of hamster Bcl-2 rendered the cells more resistant to MNNG-induced cytotoxicity, which is consistent with the anti-apoptotic function of Bcl-2.

Alkylation↗
PubMed2005

Microscopic verification of topological electron-vortex binding in the lowest Landau-level crystal state.

When two-dimensional electrons are subjected to a very strong magnetic field, they are believed to form a triangular crystal. By a direct comparison with the exact wave function, we demonstrate that this crystal is not a simple Hartree-Fock crystal of electrons but an inherently quantum mechanical crystal characterized by a nonperturbative binding of quantized vortices to electrons. It is suggested that this has qualitative consequences for experiment.

Journal Article↗
PubMed2001

Quantitative evaluation of nonrepetitive phase-encoding orders for first-pass, 3D contrast-enhanced MR angiography.

In this work, a detailed quantitative comparison was made of many alternative phase-encoding strategies for first-pass 3D MR angiography where each phase encode is only sampled once during the transient passage of contrast agent. A series of standard sequential and centric phase-encoding orders including elliptical centric were tested, as well as a new order called elliptical sequential. The characteristics of the different phase-encoding orders were tested using a computer simulation followed by experimental verification using a variable flip angle scheme. The characteristics to be considered included: arterial intensity, arterial-to-venous contrast, degree of artifact, and the blurring of the point-spread function. By making use of a wide range of start times and a rapidly varying contrast curve, the quantitative results clearly indicate the widely varying merits of each phase-encoding order. In general, when an optimal start time is used techniques that sample the low k-space views most compactly will produce the best results; however, the same methods are more problematic when the bolus arrival time deviates substantially from that expected.

Computer Simulation↗
PubMed1993

Biophysical tools for structure-based drug design.

The emerging understanding of the structural basis of biological function has made possible a new technology of rational drug design. This technology uses a combination of modeling and intensive computational tools, but also relies critically on direct structural methods for verification and to provide direction for new leads. The present work illustrates applications of this technology to ligand design for several model systems, including iterative modeling and crystallographic design of streptavidin ligands, ranking of streptavidin ligands using comparative molecular field analysis and ranking of thermolysin inhibitors using Poisson-Boltzman methods.

Amino Acid Sequence↗
PubMed2001

Age-at-death diagnosis and determination of life-history parameters by incremental lines in human dental cementum as an identification aid.

Incremental lines in acellular extrinsic fiber cementum of 91 roots from 80 freshly extracted teeth have been investigated for a verification of the suitability of pathological teeth for a valid age-at-death diagnosis. Independent from tooth type, the accuracy of histological age-at-death diagnosis is clearly a function of a tooth's pathological state. Various periodontal diseases lead to a reduced number of incremental lines, while teeth with a sufficient nutritional support of their root showed a deviation of the histological age from the known actual age of 2-3 years only. For all patients, a detailed query concerning a variety of life-history parameters was established. We are able to show that especially previous pregnancies, skeletal traumata and renal diseases which all have a marked influence on the calcium metabolism result in hypomineralized incremental lines. The year of production of these hypomineralized lines could be dated precisely. Differential quality of incremental lines can, therefore, serve as a valuable tool in identification cases.

Adult↗
PubMed2002

Arithmetic fact retrieval and working memory in schizophrenia.

Despite its importance in every-day life and vocational rehabilitation, arithmetic ability has rarely been investigated in schizophrenic patients. Those few studies reporting arithmetic deficits in schizophrenia, however, administered complex calculation tasks which drew not only on arithmetic abilities, but also on working memory resources known to be impaired in schizophrenia. In the present study, arithmetic abilities and working memory functions were investigated in schizophrenic patients (n=24) and healthy control subjects (n=24). Arithmetic fact retrieval was assessed in single-digit multiplication and corresponding division problems using a result verification task which minimized working memory demands. Problem size and the disparity of the proposed result were manipulated. The storage component of working memory was tested with a digit span forward task and the executive control component with a digit span backward as well as with verbal fluency tasks. Schizophrenic patients performed worse than controls only in the executive tasks. Digit span forward was preserved. In the arithmetic tasks, groups did not differ from each other, and a similar pattern of task manipulations was obtained. Hence, despite the executive control deficit retrieval of arithmetic facts is preserved in schizophrenia. Moreover, the same underlying cognitive processes as in control subjects are involved.

Adult↗
PubMedDate not supplied

A dynamic two-dimensional phantom for ultrasound hyperthermia controller testing.

A new thin layer phantom for testing hyperthermia controllers has been constructed and evaluated using an ultrasound hyperthermia system. The phantom's thermal behaviour agrees with the characteristics of the Pennes' bio-heat transfer equation (BHTE). In particular, the experimental and theoretical results agree in the following ways. First, with respect to the power deposition: for a given power magnitude and scan radius, the shape of the temperature distribution across the phantom corresponds to the shape predicted by the BHTE and the experimental and theoretical temperature values agree closely; when the power magnitude is varied at a fixed scan radius, the average temperature of the phantom varies linearly with the applied power, and as the scan radius is varied at a fixed power magnitude, the average temperature increases with decreasing scan radius size. Secondly, with respect to perfusion: increasing or decreasing the flow rate over the phantom simulates an increase or decrease in the BHTE perfusion term, and the estimated perfusion values are dependent on flow rate only, and are not functions of power or geometry. The combination of these experimental and theoretical results validate the phantom's potential for testing feedback control systems, particularly for future use in the development and verification of model-based controllers. The use of this phantom should improve and accelerate the testing and evaluation of feedback control systems, and reduce the need for animal and human testing.

Animals↗