Search results for "ToF"

Comparison of two methods skipping cell lysis and protein extraction for identification of bacteria from blood cultures by matrix-assisted laser deso…

2019

ABSTRACT Objective Matrix-assisted laser desorption/ionization time-of-flight mass-spectrometry (MALDI-TOF MS) is widely used for fast identification of bacteria from blood cultures (BC). We compared the performance of two procedures, one including a pre-enrichment step in brain heart infusion and the other a direct method using vacutainer separator gel tubes (DI), for identification of bacteria from blood cultures by MALDI-TOF MS. Material and methods We first prepared a training set of 20 simulated bacteremia specimens, including 10 Gram-negative and 10 Gram-positive species. A total of 145 non-consecutive BCs flagged as positive (68 Gram-negative rods, and 77 Gram-positive cocci) were pr…

Using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the characterization of functionalized carbon nanotubes

2013

RATIONALE: Functionalization of carbon nanotubes (CNTs) generates complex systems that require the development of suitable characterization protocols. New techniques have been explored, and existing analytical and spectroscopic methods to characterize functionalized CNTs have been adapted. Presently, chemical characterization of functionalized CNTs (f-CNTs) remains a difficult task. METHODS: Matrix-assisted laser desorption/ionization (MALDI) analysis is performed on f-MWCNT samples prepared via grafting or absorption of anti-oxidant (AO) molecules on both MWCNT-COOH and MWCNT-OH. Covalently functionalized MWCNTs were subjected to thermal degradation and/or hydrolysis reaction before analys…

MALDI-TOF mass spectrometry identification of filamentous fungi in the clinical laboratory.

2014

Pôle MERS F. Dalle; International audience; This study aimed to validate the effectiveness of a standardised procedure for the MALDI-TOF mass spectrometry (MS)-based identification on a large sample of filamentous fungi routinely identified in university hospitals' laboratories. Non-dermatophyte filamentous fungi prospectively isolated in the routine activity of five teaching hospitals in France were first identified by conventional methods in each laboratory and then by MS in one centre. DNA sequence-based identification resolved discrepancies between both methods. In this study, of the 625 analysed filamentous fungi of 58 species, 501 (80%) and 556 (89%) were correctly identified by conve…

A Multicentre Pilot Study of a Two-Tier Newborn Sickle Cell Disease Screening Procedure with a First Tier Based on a Fully Automated MALDI-TOF MS Pla…

2019

The reference methods used for sickle cell disease (SCD) screening usually include two analytical steps: a first tier for differentiating haemoglobin S (HbS) heterozygotes, HbS homozygotes and β-thalassemia from other samples, and a confirmatory second tier. Here, we evaluated a first-tier approach based on a fully automated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) platform with automated sample processing, a laboratory information management system and NeoSickle® software for automatic data interpretation. A total of 6701 samples (with high proportions of phenotypes homozygous (FS) or heterozygous (FAS) for the inherited genes for sickle h…

Identification clinique par spectrométrie de masse MALDI-TOF des champignons filamenteux : construction de banques de données pour les dermatophytes …

2015

Gaļas bojāšanos izraisošo mikroorganismu identifikācija

2016

Bakalaura darba tēma: Gaļas bojāšanos izraisošo mikroorganismu identifikācija. Šī bakalaura darba mērķis bija noskaidrot dominējošos mikroorganismus gaļas bojāšanās laikā atkarībā no temperatūras un iepakojuma veida. Tika iegādāta vistas, cūkas un liellopa gaļa no Rīgas centrāltirgus. Gaļa 16 dienas uzglabāta dažādās temperatūrās 2, 8 un 12 oC grādi. Šī darba laikā tika identificēti 829 mikrooganismi, kas veidoja 82 mikroorganismu sugas. Vistas un cūkas bojātā gaļā dominējošās baktērjas ir Pseudomonas spp, bet liellopa gaļā dominē Hafnia alvei. Gaļas bojāšanās laikā 12oC uzglabāšanas temperatūrā mikroflorā dominē Enterobacteriaceae dzimtas baktērijas, bet 2oC un 8oC temperatūrā dominē Pseud…

Guidelines for the use and interpretation of assays for monitoring cell death in higher eukaryotes

2009

Cell death is essential for a plethora of physiological processes, and its deregulation characterizes numerous human diseases. Thus, the in-depth investigation of cell death and its mechanisms constitutes a formidable challenge for fundamental and applied biomedical research, and has tremendous implications for the development of novel therapeutic strategies. It is, therefore, of utmost importance to standardize the experimental procedures that identify dying and dead cells in cell cultures and/or in tissues, from model organisms and/or humans, in healthy and/or pathological scenarios. Thus far, dozens of methods have been proposed to quantify cell death-related parameters. However, no guid…

Kalcija ortofosfāta sintēzes apstākļu pētījumi

2015

Kalcija ortofosfāta sintēzes apstākļu pētījumi. Bezzaponnaja V., zinātniskais vadītājs Dr. chem., asoc. prof. Švirksts J. Bakalaura darbs, 48 lappuses, 19 tabulas, 26 attēli, 42 literatūras avoti, 1 pielikums. Latviešu valodā. Darbā apkopota informācija par dabīgajiem kalcija fosfātiem un hidroksīlapatītiem, to sintēzes un pētīšanas metodēm, katjonu aizvietošanu apatītos un fosfātos, kalcija fosfātu biomateriāliem. Darbā veikta kalcija ortofosfātu sintēze ar dažādu kalcija/fosfora molāro attiecību robežās no 1,20 līdz 1,60. Izmantojot kompleksonometriju un fotometriju noteikts kalcija un fosfora saturs sintezētajos paraugos. Paraugu fāzu noteikšanai pirms un pēc karsēšanas tika izmantota re…

Overrating Classifier Performance in ROC Analysis in the Absence of a Test Set: Evidence from Simulation and Italian CARATkids Validation

2019

Background The use of receiver operating characteristic curves, or “ROC analysis,” has become quite common in biomedical research to support decisions. However, sensitivity, specificity, and misclassification rates are still often estimated using the training sample, overlooking the risk of overrating the test performance. Methods A simulation study was performed to highlight the inferential implications of splitting (or not) the dataset into training and test set. The normality assumption was made for the classifier given the disease status, and the Youden's criterion considered for the detection of the optimal cutoff. Then, an ROC analysis with sample split was applied to assess the disc…

Reduced firing rates of pyramidal cells in the frontal cortex of APP/PS1 can be restored by acute treatment with levetiracetam

2020

Contains fulltext : 229488.pdf (Publisher’s version ) (Open Access) Contains fulltext : 229488pre.pdf (Author’s version preprint ) (Open Access) In recent years, aberrant neural oscillations in various cortical areas have emerged as a common physiological hallmark across mouse models of amyloid pathology and patients with Alzheimer's disease. However, much less is known about the underlying effect of amyloid pathology on single cell activity. Here, we used high-density silicon probe recordings from frontal cortex area of 9-month-old APP/PS1 mice to show that local field potential power in the theta and beta band is increased in transgenic animals, whereas single-cell firing rates, specifica…