61 research outputs found

    Quantitative Structure-Retention Relationships (QSRR) for Chromatographic Separation of Disazo and Trisazo 4,4\u27-Diaminobenzanilide-based Dyes

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    For a series of 23 disazo and trisazo 4,4\u27-diaminobenzanilide-based direct dye molecules, thechromatographic mobilities, extrapolated to modifier-free conditions (RM0 values), were determinedfrom reverse-phase thin-layer chromatography (RP-TLC) experiments. Traditional and rational QSAR/QSPR modelling techniques have been applied to find a quantitative structure-retention relationship (QSRR) for the dyes. Molecular dye structures were energy minimized by both molecular mechanics and quantum chemical calculations. A variety of 1D to 3D molecular descriptors taking into account size, shape, symmetry, electronic structure, atom or group distribution, and hydrophobicity of the dyes was derived from the optimized three-dimensional geometries. Multiple linear regression (MLR) and artificial neural network (ANN) modelling revealed that the R M0 values can be successfully expressed by a combination of hydrophobic and polarity dye structural parameters. Additional comparative molecular field (CoMFA) and similarity index (CoMSIA) analyses suggested almost equal contribution of both steric and electrostatic fields to the chromatographic mobility and the major role of hydrophobic and electrostatic interactions with the chromatographic environment

    A Monolithic Piezoelectric Miniature Robot with 5 DOF

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    Mutation of the glucosinolate biosynthesis enzyme cytochrome P450 83A1 monooxygenase increases camalexin accumulation and powdery mildew resistance

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    Small secondary metabolites, including glucosinolates and the major phytoalexin camalexin, play important roles in immunity in Arabidopsis thaliana. We isolated an Arabidopsis mutant with increased resistance to the powdery mildew fungus Golovinomyces cichoracearum and identified a mutation in the gene encoding cytochrome P450 83A1 monooxygenase (CYP83A1), which functions in glucosinolate biosynthesis. The cyp83a1-3 mutant exhibited enhanced defense responses to G. cichoracearum and double mutant analysis showed that this enhanced resistance requires NPR1, EDS1, and PAD4, but not SID2 or EDS5. In cyp83a1-3 mutants, the expression of genes related to camalexin synthesis increased upon G. cichoracearum infection. Significantly, the cyp83a1-3 mutant also accumulated higher levels of camalexin. Decreasing camalexin levels by mutation of the camalexin synthetase gene PAD3 or the camalexin synthesis regulator AtWRKY33 compromised the powdery mildew resistance in these mutants. Consistent with these observations, overexpression of PAD3 increased camalexin levels and enhanced resistance to G. cichoracearum. Taken together, our data indicate that accumulation of higher levels of camalexin contributes to increased resistance to powdery mildew

    Age as an independent factor for the development of neuropathy in diabetic patients

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    Simona Popescu,1,2 Bogdan Timar,2,3 Flavia Baderca,4,5 Mihaela Simu,6,7 Laura Diaconu,1,2 Iulian Velea,8,9 Romulus Timar1,2 12nd Department of Internal Medicine, “Victor Babes” University of Medicine and Pharmacy, 2Clinic of Diabetes, Nutrition and Metabolic Diseases, Emergency Clinical County Hospital, 3Department of Functional Sciences, 4Department of Microscopic Morphology, “Victor Babes” University of Medicine and Pharmacy, 5Service of Pathology, Emergency City Hospital, 6Department of Neurosciences, “Victor Babes” University of Medicine and Pharmacy, 7Clinic of Neurology, Emergency Clinical County Hospital, 8Department of Pediatrics, “Victor Babes” University of Medicine and Pharmacy, 9Clinic of Pediatrics, Emergency Clinical County Hospital, Timisoara, Romania Abstract: Population aging is unprecedented, without parallel in the history of humanity. As type 2 diabetes mellitus is predominantly more prevalent in aging populations, this creates a major public health burden. Older adults with diabetes have the highest rates of major lower-extremity amputation, myocardial infarction, visual impairment, and end-stage renal disease of any age group. The aims of our study were to assess whether age is an independent factor for the occurrence of diabetic neuropathy (DN), and to evaluate the relationship between the presence and the severity of DN and the diabetes duration and blood glucose level. In this study, we enrolled 198 patients, previously diagnosed with type 2 diabetes mellitus. For all patients, we measured hemoglobin A1c (HbA1c), lipid profile, and body mass index and we assessed the presence and severity of DN using the evaluation of clinical signs and symptoms. Patients had a median age of 62 years, with a median of diabetes duration of 7 years; 55.1% of the patients were men and the average HbA1c in the cohort was 8.2%. The prevalence of DN according to Michigan Neuropathy Screening Instrument was 28.8%, being significantly and positively correlated with higher age (65 vs 59 years; P=0.001) and HbA1c (8.6% vs 8.0%; P=0.027). No significant correlations were observed between the severity of DN and diabetes duration, body mass index (31.9 vs 29.9 kg/m2), or the number of centimeters exceeding the normal waist circumference (25.2 vs 17.3 cm; P=0.003). In conclusion, age influences the presence of DN, independent on other risk factors. This influence persists even after adjusting for other, very important risk factors, like blood glucose level or diabetes duration. Keywords: peripheral neuropathy, elderly patients, type 2 diabetes mellitus, body mass index, hemoglobin A1c, diabetic neuropath

    A Polymeric Paraffin Microactuator

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    Versatile microchip utilising ultrasonic manipulation of microparticles

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    This paper presents the concept and initial work on a microfluidic platform for bead-based analysis of biological sample. The core technology in this project is ultrasonic manipulation and trapping of particle in array configurations by means of acoustic forces. The platform is ultimately aimed for parallel multistep bioassays performed on biochemically activated microbeads (or particles) using submicrolitre sample volumes. A first prototype with three individually controlled particle trapping sites has been developed and evaluated. Standing ultrasonic waves were generated across a microfluidic channel by integrated PZT ultrasonic microtransducers. Particles in a fluid passing a transducer were drawn to pressure minima in the acoustic field, thereby being trapped and confined laterally over the transducer. It is anticipated that acoustic trapping using integrated transducers can be exploited in miniaturised total chemical analysis systems (μTAS), where e.g. microbeads with immobilised antibodies can be trapped in arrays and subjected to minute amounts of sample followed by a reaction, detected using fluorescence. Preliminary results indicate that the platform is capable of handling live cells as well as microbeads. A first model bioassay with detection of fluorescein marked avidin binding to trapped biotin beads has been evaluate
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