950 research outputs found
Code Quality Evaluation Methodology Using The ISO/IEC 9126 Standard
This work proposes a methodology for source code quality and static behaviour
evaluation of a software system, based on the standard ISO/IEC-9126. It uses
elements automatically derived from source code enhanced with expert knowledge
in the form of quality characteristic rankings, allowing software engineers to
assign weights to source code attributes. It is flexible in terms of the set of
metrics and source code attributes employed, even in terms of the ISO/IEC-9126
characteristics to be assessed. We applied the methodology to two case studies,
involving five open source and one proprietary system. Results demonstrated
that the methodology can capture software quality trends and express expert
perceptions concerning system quality in a quantitative and systematic manner.Comment: 20 pages, 14 figure
Interaction of dental pulp stem cells with Biodentine and MTA after exposure to different environments
Objective: The aim of the present study was to evaluate and compare the cytotoxic effects of Biodentine and MTA on dental pulp stem cells (DPSCs) and to assess cell viability and adherence after material exposure to an acidic environment. Material and Methods: DPSCs were cultured either alone or in contact with either: Biodentine; MTA set for 1 hour; or MTA set for 24 hours. After 4 and 7 days, cell viability was measured using the MTT assay. Biodentine and MTA were also prepared and packed into standardized bovine dentin disks and divided into three groups according to the storage media (n=6/group): freshly mixed materials without storage medium (Group A); materials stored in saline (Group B); materials stored in citric acid buffered at pH 5.4 (Group C). After 24 hours, DPSCs were introduced in the wells and cell adherence, viability, and cellular morphology were observed via confocal microscopy after three days of culture. Cell viability was analyzed using repeated-measures analysis of variance test with Tukey's post hoc tests (α=0.05). Results: Biodentine expressed significantly higher cell viability compared with all other groups after 4 days, with no differences after 7 days. Notably, cell viability was significantly greater in 24-hour set MTA compared with 1-hour set MTA and control groups after 7 days. Material exposure to an acidic environment showed an increase in cell adherence and viability in both groups. Conclusions: Biodentine induced a significantly accelerated cell proliferation compared with MTA. Setting of these materials in the presence of citric acid enhanced DPSC viability and adherence
Application of nano-hydroxyapatite/chitosan scaffolds on rat calvarial critical-sized defects : a pilot study
The purpose of this pilot study was to evaluate for the first time the effect of 75/25 w/w nano-Hydroxyapatite/Chitosan (nHAp/CS) scaffolds on Guided Bone Regeneration (GBR) in rat calvarial critical-sized defects (CSDs). Six adult Sprague Dawley rats, 3 males and 3 females, were used. Two CSDs, full thickness and 5mm in diameter, were trephined in both sides of the parietal bone. The right CSD was filled with nHAp/CS scaffold, while the left CSD remained empty, as the control group. The wound was sutured in layers. Rats were euthanized with diethyl ether inhalation at 2, 4 and 8 weeks after surgical procedure. Histological and histomorphometric analysis was performed within distinct regions of interest (ROI): the lateral area inward of the middle sagittal seam; the lateral area outward of the middle sagittal seam and the central area. The mean surface of newly formed bone (in ?m2) in the lateral area inward of the middle sagittal seam of all rats was significantly higher (P=0.039) in the experimental group (91733.00±38855.60) than the control group (46762.17±25507.97). The NOex-c, defined as total number of osteocytes (OST) in newly formed bone surface in experimental group [experimental OST] minus the total number of osteocytes in newly formed bone surface in control group [control OST], was significantly greater (P=0.029) at 4th week post-surgery. Within the experimental group, a statistically significant increase (P=0.042) in the surface of newly formed bone was noticed in rats euthanized in 4th week compared with rats euthanized in 2nd week after surgery in the lateral area inward of the middle sagittal seam. The results of this study suggest that 75/25 w/w nHAp/CS scaffolds should be considered as a suitable biomaterial for GBR
Doppler tissue imaging unmasks right ventricular function abnormalities in HIV-infected patients
Background: We sought to investigate right ventricular (RV) function with Doppler tissue
imaging (DTI) in human immunodeficiency virus (HIV)-infected patients receiving highly-active antiretroviral treatment, without any heart-related symptoms.
Methods: We studied 38 asymptomatic HIV patients (aged 44.5 ± 9.2 years, 22 of them men)
and 25 age-matched and sex-matched controls. All subjects underwent conventional and DTI
estimation of left ventricular (LV) systolic and diastolic function, measuring peak systolic and
diastolic myocardial velocities at the mitral annulus (Sm, Em, Am). Two-dimensional (2-D)
echocardiographic study of the right ventricle (RV) was performed from the four-chamber view, and
RV end-diastolic dimensions were measured. DTI recordings from the RV free wall at the tricuspid
annulus were used to determine systolic (SmRV) and diastolic function (EmRV and AmRV).
Results: HIV-infected patients compared to controls exhibited significantly lower peak systolic
velocities at the septal-SmIVS (7.9 ± 1.3 vs 9.1 ± 1.4 cm/s, p = 0.002) and lateral mitral
annulus - SmLAT (9.8 ± 1.7 vs 11.2 ± 1.3 cm/s, p = 0.025); no difference was observed
regarding conventional 2-D examination of LV systolic and diastolic function and DTI-derived Em and Am. No significant difference occurred between HIV patients and controls
regarding RV end-diastolic dimensions and pulmonary artery systolic pressure. However,
SmRV (13.8 ± 1.6 vs 14.9 ± 2.2 cm/s, p = 0.040), EmRV (11.6 ± 3 vs 13.5 ± 2.6 cm/s, p = 0.028)
and AmRV (10.9 ± 2.5 vs 13.8 ± 4 cm/s, p = 0.003) were significantly reduced in HIV
patients as compared to controls.
Conclusions: DTI unmasks subtle and otherwise undetectable abnormalities of the longitudinal
LV systolic function and both RV systolic and diastolic function, in asymptomatic HIV
patients receiving highly-active antiretroviral treatment. (Cardiol J 2010; 17, 6: 587-593
Comparison of Bacterial Community Composition of Primary and Persistent Endodontic Infections Using Pyrosequencing
Elucidating the microbial ecology of endodontic infections (EI) is a necessary step in developing effective intra-canal antimicrobials. The aim of the present study was to investigate the bacterial composition of symptomatic and asymptomatic primary and persistent infections in a Greek population, using high throughput sequencing methods
Speeding up Energy System Models - a Best Practice Guide
Background
Energy system models (ESM) are widely used in research and industry to analyze todays and future energy systems and potential pathways for the European energy transition. Current studies address future policy design, analysis of technology pathways and of future energy systems. To address these questions and support the transformation of today’s energy systems, ESM have to increase in complexity to provide valuable quantitative insights for policy makers and industry. Especially when dealing with uncertainty and in integrating large shares of renewable energies, ESM require a detailed implementation of the underlying electricity system. The increased complexity of the models makes the application of ESM more and more difficult, as the models are limited by the available computational power of today’s decentralized workstations. Severe simplifications of the models are common strategies to solve problems in a reasonable amount of time – naturally significantly influencing the validity of results and reliability of the models in general.
Solutions for Energy-System Modelling
Within BEAM-ME a consortium of researchers from different research fields (system analysis, mathematics, operations research and informatics) develop new strategies to increase the computational performance of energy system models and to transform energy system models for usage on high performance computing clusters. Within the project, an ESM will be applied on two of Germany’s fastest supercomputers. To further demonstrate the general application of named techniques on ESM, a model experiment is implemented as part of the project. Within this experiment up to six energy system models will jointly develop, implement and benchmark speed-up methods. Finally, continually collecting all experiences from the project and the experiment, identified efficient strategies will be documented and general standards for increasing computational performance and for applying ESM to high performance computing will be documented in a best-practice guide
Assessment of osteoarthritis candidate genes in a meta-analysis of nine genome-wide association studies
OBJECTIVE:
To assess candidate genes for association with osteoarthritis (OA) and identify promising genetic factors and, secondarily, to assess the candidate gene approach in OA.
METHODS:
A total of 199 candidate genes for association with OA were identified using Human Genome Epidemiology (HuGE) Navigator. All of their single-nucleotide polymorphisms (SNPs) with an allele frequency of >5% were assessed by fixed-effects meta-analysis of 9 genome-wide association studies (GWAS) that included 5,636 patients with knee OA and 16,972 control subjects and 4,349 patients with hip OA and 17,836 control subjects of European ancestry. An additional 5,921 individuals were genotyped for significantly associated SNPs in the meta-analysis. After correction for the number of independent tests, P values less than 1.58 Ă— 10(-5) were considered significant.
RESULTS:
SNPs at only 2 of the 199 candidate genes (COL11A1 and VEGF) were associated with OA in the meta-analysis. Two SNPs in COL11A1 showed association with hip OA in the combined analysis: rs4907986 (P = 1.29 Ă— 10(-5) , odds ratio [OR] 1.12, 95% confidence interval [95% CI] 1.06-1.17) and rs1241164 (P = 1.47 Ă— 10(-5) , OR 0.82, 95% CI 0.74-0.89). The sex-stratified analysis also showed association of COL11A1 SNP rs4908291 in women (P = 1.29 Ă— 10(-5) , OR 0.87, 95% CI 0.82-0.92); this SNP showed linkage disequilibrium with rs4907986. A single SNP of VEGF, rs833058, showed association with hip OA in men (P = 1.35 Ă— 10(-5) , OR 0.85, 95% CI 0.79-0.91). After additional samples were genotyped, association at one of the COL11A1 signals was reinforced, whereas association at VEGF was slightly weakened.
CONCLUSION:
Two candidate genes, COL11A1 and VEGF, were significantly associated with OA in this focused meta-analysis. The remaining candidate genes were not associated
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