43 research outputs found

    Identification of Nonlinear Systems Using the Hammerstein-Wiener Model with Improved Orthogonal Functions

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    Hammerstein-Wiener systems present a structure consisting of three serial cascade blocks. Two are static nonlinearities, which can be described with nonlinear functions. The third block represents a linear dynamic component placed between the first two blocks. Some of the common linear model structures include a rational-type transfer function, orthogonal rational functions (ORF), finite impulse response (FIR), autoregressive with extra input (ARX), autoregressive moving average with exogenous inputs model (ARMAX), and output-error (O-E) model structure. This paper presents a new structure, and a new improvement is proposed, which is consisted of the basic structure of Hammerstein-Wiener models with an improved orthogonal function of Müntz-Legendre type. We present an extension of generalised Malmquist polynomials that represent Müntz polynomials. Also, a detailed mathematical background for performing improved almost orthogonal polynomials, in combination with Hammerstein-Wiener models, is proposed. The proposed approach is used to identify the strongly nonlinear hydraulic system via the transfer function. To compare the results obtained, well-known orthogonal functions of the Legendre, Chebyshev, and Laguerre types are exploited

    Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

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    Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

    Pediatric Anesthesia Providers’ Perspective on the Real-Life Implementation of the Philips Visual Patient Avatar: A Qualitative Study

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    The Philips Visual Patient Avatar represents an alternative method of patient monitoring that, according to computer-based simulation studies, enhances diagnostic accuracy and confidence and reduces workload. After its clinical integration, we assessed pediatric anesthesia providers’ perspectives on this technology. This is a single-center qualitative study, conducted at the University Hospital Zurich using in-depth individual interviews. We aimed to identify the advantages and limitations of the Visual Patient Avatar in pediatric anesthesia and to assess children’s and parents’ reactions from caregivers’ perspectives. Thematic analysis was used to identify the dominant themes. Fourteen members of the institution’s pediatric anesthesia team were interviewed. The most prevalent themes were children’s positive reactions towards the Visual Patient Avatar (92.9%) and enhanced speed in problem identification (71.4%). Additionally, 50% of participants reported finding the Visual Patient Avatar useful for diverting children’s attention during anesthesia induction, and 50% suggested that its vital sign thresholds should be adaptable for different age groups. The study revealed that the Visual Patient Avatar was recognized as a tool in pediatric anesthesia, enabling prompt identification of underlying issues and receiving positive feedback from both children and parents. The most commonly voiced wish for improvement in the study was the ability to customize the Visual Patient Avatar’s thresholds for different age groups

    Efikasnost različitih insekticida u poljskim uslovima u suzbijanju repičinog sjajnika (Meligethes aeneus F.) u usevima ozime uljane repice

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    Since pollen beetle, M. aeneus, is usually controlled by insecticides, the efficacy of several compounds with different modes of action against adult beetles was studied in a threeyear field study. The selected insecticides were: three pyrethroids (lambda-cyhalothrin, alpha-cypermethrin and bifenthrin), an oganophosphate (pirimiphos-methyl), a combination of an organophosphate and a pyrethroid (chlorpyrifos + cypermethrin) and a neonicotinoid (thiacloprid). The insecticides were applied at label rates to winter rapeseed crops at the moment of visible but still closed flower buds (BBCH 55-57). In all experiments, the efficacy of pyrethroids and the organophosphate ranged from 90-100%, while the efficacy of the neonicotinoid was 85-95%. Therefore, they can be recommended for control of pollen beetle in Serbia.S obzirom da gajenje uljane repice za sobom povlači i primenu insekticida za suzbijanje repičinog sjajnika kao najštetnije insekatske vrste, u radu je tokom trogodišnjih poljskih ogleda (2008-2010. godina) na tri lokaliteta (Kovin, Smederevo i Požarevac) ispitana efikasnost insekticida rаzličitih mehаnizаmа delovаnjа: piretroidа (lаmbdа-cihаlotrin, аlfа-cipermetrin, bifentrin), orgаnofosfаtа (pirimifos-metil), kombinаcije orgаnofosfаtа i piretroidа (hlorpirifos + cipermetrin) i neonikotinoidа (tiаkloprid) za imaga M. aeneus. Komercijalne formulacije insekticida su primenjivаne u preporučenim dozаmа u usevima ozime uljаne repice u vreme vidljivih cvetnih pupoljaka, ali još zatvorenih (BBCH 55-57). Efikasnost piretroida i organofosfata je tokom svih ogleda bila 90-100%, a neonikotinoida 85-95%, pa se zbog ispoljene visoke efikasnosti može preporučiti njihova primena u Srbiji

    Age estimation in children based on open apices measurement in the Serbian population: Belgrade Age Formula (BAF)

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    Background: Cameriere’s method has been tested in many populations and is widely accepted for dental age estimation. Aim: To establish a new formula for age estimation by measurement of open apices of mandibular teeth based on Cameriere’s European formula. Subjects and methods: Panoramic radiographs of 333 healthy Serbian children aged 5–14 years were analysed by two independent researchers. The new formula – Belgrade Age Formula (BAF) – was created and tested on the same Serbian sample. Furthermore, BAF was tested on the Serbian validation sample of 126 children and 2115 Italian children aged 5–14 years. Results: In the Serbian sample, the residuals of the BAF and European formula demonstrated that BAF is significantly better in age estimation than the European formula. No significant difference was found in females from the Serbian validation sample between dental and chronological age when BAF was applied. For males, the BAF and European formula had similar accuracy. In the Italian sample, the mean differences between estimated and real age for the European formula were −0.214 ± 0.934 and 0.109 ± 0.773 for females and males, respectively, while for BAF these differences were 0.182 ± 0.951 and −0.195 ± 0.923 for females and males, respectively. Conclusion: BAF was found to be accurate in the Serbian and Italian populations

    Porotic paradox: distribution of cortical bone pore sizes at nano- and micro-levels in healthy vs. fragile human bone

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    Bone is a remarkable biological nanocomposite material showing peculiar hierarchical organization from smaller (nano, micro) to larger (macro) length scales. Increased material porosity is considered as the main feature of fragile bone at larger length-scales. However, there is a shortage of quantitative information on bone porosity at smaller length-scales, as well as on the distribution of pore sizes in healthy vs. fragile bone. Therefore, here we investigated how healthy and fragile bones differ in pore volume and pore size distribution patterns, considering a wide range of mostly neglected pore sizes from nano to micron-length scales (7.5 to 15000 nm). Cortical bone specimens from four young healthy women (age: 35 +/- 6 years) and five women with bone fracture (age: 82 +/- 5 years) were analyzed by mercury porosimetry. Our findings showed that, surprisingly, fragile bone demonstrated lower pore volume at the measured scales. Furtnermore, pore size distribution showed differential patterns between healthy and fragile bones, where healthy bone showed especially high proportion of pores between 200 and 15000 nm. Therefore, although fragile bones are known for increased porosity at macroscopic level and level of tens or hundreds of microns as firmly established in the literature, our study with a unique assessment range of nano-to micron-sized pores reveal that osteoporosis does not imply increased porosity at all length scales. Our thorough assessment of bone porosity reveals a specific distribution of porosities at smaller length-scales and contributes to proper understanding of bone structure which is important for designing new biomimetic bone substitute materials. [GRAPHICS

    Surface characterization of the cement for retention of implant supported dental prostheses: In vitro evaluation of cement roughness and surface free energy

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    Background: Material surface free energy and surface roughness strongly influence the bacterial adhesion in oral cavity. The aim of this study was to analyze these two parameters in various commercial luting agents used for cementation of implant restorations. Materials and methods: Zinc-based, glass-ionomers, resin modified glass-ionomer and resin-cements were investigated. Contact angle and surface free energy were measured by contact angle analyzer using Image J software program. Materials average roughness and fractal dimension were calculated based on Atomic Force Microscope topography images. Results: Zinc phosphate cements presented significantly higher total surface free energy and significantly lower dispersive component of surface free energy compared to other groups, while resin-cements showed significantly lower polar component than other groups. The surface roughness and fractal dimension values were statistically the highest in the zinc phosphate cements and the lowest for the glass-ionomers cements. Conclusion: Glass-ionomers-cements presented lower values of surface free energy and surface roughness than zinc phosphate and resin cements, indicating that their surfaces are less prone to biofilm adhesion. Practical implications: Within limitations of an in vitro trial, our results indicate that glass-ionomers-cements could be the cements of choice for fixation of cement retained implant restorations due to superior surface properties compared to zinc phosphate and resin cements, which may result in reduced plaque formation and presumably prevent periimplant infection. (C) 2014 Elsevier B.V. All rights reserved

    Age-related deterioration in trabecular bone mechanical properties at material level: Nanoindentation study of the femoral neck in women by using AFM

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    Despite general belief that the mechanical properties of bone material contribute to whole bone strength, it is still obscure what the age effects are on mechanical behavior of the bone material, particularly in the case of the femoral neck trabeculae. In this study, atomic force microscopy was used for imaging and measuring the size of mineral grains, as well as nano-scale mechanical characterization (nanoindentation) of the bone mineralized matrix of trabeculae, with the aim to explore the age effects on bone elasticity and give new insight into age-related bone fragility. The bone samples in this study comprised trabecular bone specimens of the femoral neck region, collected from eight skeletal healthy women (five young adults: 27-38 yrs., three elderly: 83-94 yrs.) at autopsy. Bone trabeculae in the elderly displayed a higher modulus and nanohardness, signifying a decreased amount of energy that can be accommodated by the bone tissue during loading. Regression analysis revealed that nearly 65% of variability in the bone matrix elastic modulus can be statistically explained by the changes in size of the matrix mineral grains. This study revealed that the bone trabeculae of elderly women express less elastic behavior at the material level, which makes them more vulnerable to unusual impact loads originating from a fall. The observed age-related structural and mechanical alteration at the bone material level adds new evidence for understanding why hip fractures are more frequent in elderly women. (C) 2011 Elsevier Inc. All rights reserved

    Nano-structural and compositional basis of devitalized tooth fragility

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    Objective. Increased tooth fragility after devitalization is commonly observed but there is no definite mechanistic explanation for such phenomenon. Therefore, it is important to analyze more profoundly structural and compositional properties of this altered form of dentin. The present study investigates the differences between normal and devitalized dentin using advanced techniques. Methods. Atomic force microscopic imaging (AFM), energy dispersive X-ray analysis (EDX) and micro-Raman spectroscopy were performed on 16 dentin specimens, eight vital and eight that underwent root-canal treatment at least two years before extraction and had no infection in root canals before or after devitalization. Results. The mean size of mineral crystals showed by AFM was larger in devitalized than in healthy dentin in the same age category. AFM phase shifts in devitalized cases revealed altered mechanical characteristics and suggested differences in composition of material between devitalized teeth and healthy controls. No significant difference in Ca/P ratio between vital and devitalized teeth was found using EDX. However, micro-Raman analyses showed that in devitalized teeth, apart from hydroxyapatite, dentin contained significant amounts of apatite phases with lower calcium content: octacalcium phosphate, dicalcium phosphate dihydrate and tricalcium phosphate. Significance. Differences between vital and devitalized dentin bring new insights into the basis of devitalized tooth fragility. Larger mineral crystals could account for decreased mechanical strength in devitalized teeth. Moreover, calcium-phosphate phases with lower Ca content have lower material strength, and the presence of these phases in devitalized teeth may explain their increased fragility. (C) 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved
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