411 research outputs found

    Synthetic, Crystallographic, and Computational Study of Copper(II) Complexes of Ethylenediaminetetracarboxylate Ligands

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    Copper(II) complexes of hexadentate ethylenediaminetetracarboxylic acid type ligands H4eda3p and H4eddadp (H4eda3p = ethylenediamine-N-acetic-N,N′,N′-tri-3-propionic acid; H4eddadp = ethylenediamine-N,N′-diacetic-N,N′-di-3-propionic acid) have been prepared. An octahedral trans(O6) geometry (two propionate ligands coordinated in axial positions) has been established crystallographically for the Ba[Cu(eda3p)]·8H2O compound, while Ba[Cu(eddadp)]·8H2O is proposed to adopt a trans(O5) geometry (two axial acetates) on the basis of density functional theory calculations and comparisons of IR and UV−vis spectral data. Experimental and computed structural data correlating similar copper(II) chelate complexes have been used to better understand the isomerism and departure from regular octahedral geometry within the series. The in-plane O−Cu−N chelate angles show the smallest deviation from the ideal octahedral value of 90°, and hence the lowest strain, for the eddadp complex with two equatorial β-propionate rings. A linear dependence between tetragonality and the number of five-membered rings has been established. A natural bonding orbital analysis of the series of complexes is also presented.

    Neutral Radius Value Determination by Numerical Simulation Method at Ring Upsetting Test

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    Ring upsetting represents a basic operation for bulk forming process and has particular significance since it is used for contact friction determination. At ring upsetting by flat dies, metal flow depends upon tribological conditions present at contact surface. Thereby, two variants of metal flow are possible: a) two-way flow from neutral radius that is present at lower friction coefficient values, followed by ring’s inner radius reduction and ring’s outer radius increase. In such circumstances, neutral radius is found between inner and outer radius. b) one-way flow that occurs at higher friction coefficient values, where neutral radius is lower than ring’s inner radius. This paper is presenting the results of determination of relation between neutral radius value and friction coefficient. Such relation is determined by numerical simulation, by using Simufact.Forming software. Experimental verification of neutral radius position is conducted by metallographic analysis, for two friction coefficient values. Friction coefficient values are determined by ring upsetting by using dies, where in one case of ring upsetting, contact surfaces were ion implanted with nitroge

    Fatigue and depression in multiple sclerosis: Correlation with quality of life

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    The aim of this work was to examine the relationship between fatigue and depression, common features of multiple sclerosis (MS), and the quality of life (QOL). The study was comprised of 120 patients with clinical manifestations of definite MS. Relapsing-remitting MS was present in 76.7% patients and secondary progressive MS was present in 23.3% patients. Mean disease duration was 8.1 ± 5.6 years and the mean Expanded Disability Status Score (EDSS) was 3.5 ± 1.8 (range 1-8). Fatigue was measured with the Fatigue Severity Scale (FSS), depression was measured by the Beck Depression Inventory (BDI) and QOL was assessed using the health-related quality of life questionnaire SF-36. We observed that the global FSS score was 4.6 ± 1.8 (range 1-7) and BDI was 10.7 ± 10.3 (range 0-39). The FSS significantly and positively correlated with the BDI scores (r = 0.572; p = 0.000). The severity of fatigue had a significant impact on the quality of life (r = -0.743; p = 0.000), in particular on mental health (r = -0.749; p = 0.000). We observed a significant correlation between the severity of depression and impaired quality of life (r = -0.684; p = 0.000). This study shows that fatigue and depression are associated with impaired QOL in MS

    AC Stark-shift in CPT-based Cs miniature atomic clocks

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    We report on studies on the light-shift in caesium miniature atomic clocks based on coherent population trapping (CPT) using a micro-fabricated buffer-gas cell (MEMS cell). The CPT signal is observed on the Cs D1-line by coupling the two hyperfine ground-state Zeeman sublevels involved in the clock transition to a common excited state, using two coherent electromagnetic fields. These light fields are created with a distributed feedback laser and an electro-optical modulator. We study the light-shift phenomena at different cell temperatures and laser wavelengths around 894.6nm. By adjusting the cell temperature, conditions are identified where a miniature CPT atomic clock can be operated with simultaneously low temperature coefficient and suppressed light-shift. The impact of the light-shift on the clock frequency stability is evaluated. These results are relevant for improving the long-term frequency stability of CPT-based Cs vapour-cell clock

    The Assessment of Breeding Value of First Farrowed Sows by the Method of Selection Indices

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    The goal of this research paper was to assess the breeding value of first farrowed Swedish Landrace sows by the means of selection indices method. The traits on the basis of which the breeding value of animals was assessed are following: daily liveweight gain, average thickness of collected back fat measured at five sites and number of liveborn piglets in the first litter. The liveweight gain and carcass quality traits determined at the end of performance test were corrected for the body mass of 100kg by the method of basic indexes and following mean values were determined: for corrected daily liveweight gain (KZDP) 499.92g/day and for corrected average collected backfat thickness (KSL) 20.01mm. The first farrowed sows on average produced 8.09 liveborn piglets in the litter. Studying the effect of the gilts` birth year and season on KZDP and KSL it was determined that the gilts` birth year and season had no statistically significant influence (P>0.05) on KZDP variation but they had a statistically significant effect on KSL (P0.05) on BZPL, while the KZDP class and the age at first farrowing had a statistically significant effect on the variability of these trait (P<0.05; P<0.01). All studied traits varied statistically significantly (P<0.01) under the impact of the gilts` sire or dam. Heritability coefficients were: h2= 0.402 for KZDP, h2= 0.261 for KSL and h2= 0.177 for BZPL. The relation between KZDP and KSL was of a medium strength both at phenotype and genetic levels (rph=0.491; rg=0.411), while the relation of these traits with BZPL did not exist, except for the genetic relationship between KSL and KZDP which was of a medium strength (rg=0.252). Three equations for the selection indexes were constructed among which as the most optimal was chosen the one which includes all three traits (KZDP, KSL and BZPL) and whose correlation coefficent of selection index and aggregate genotype was rIAG = 0.5473

    A rapid and reliable determination of doxycycline hyclate by HPLC with UV detection in pharmaceutical samples

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    An accurate, sensitive and reproducible high performance liquid chromatographic (HPLC) method for the quantification of doxycycline hyclate in pharmaceutical samples has been developed and validated. The drug and the standard were eluted from a Lichrosorb RP-8 (250 mm´4.6 mm, 10 mm particle size) at 20 °C with a mobile phase consisting of methanol, acetonitrile and 0.010 M aqueous solution of oxalic acid (2:3:5, v/v/v). The flow rate was 1.25 ml min-1. A UV detector set at 350 nm was used to monitor the effluent. Each analysis required no longer than 4 min. The limits of detection and quantification were 1.15 and 3.84 μg ml-1, respectively. Recoveries for different concentrations ranged from 99.58 to 101.93 %

    Effects of Task Difficulty on Centre of Pressure Excursion and Its Inter-Trial Variability in Acrobatic Gymnastics Pyramid Performance

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    Despite the importance of balance in Acrobatic Gymnastic Pyramid performance, there is limited biomechanical analysis of balance during this activity. The aims of this study were to analyse the effect of pyramid difficulty on the centre of pressure (COP) excursion and its inter-trial variability, and determine which parameters had strongest relationship with performance. Forty-seven acrobatic gymnasts performed five trials of back and front pyramids and a third more difficult, handstand pyramid on a force platform. Pyramids were held for 7 seconds and surface area, range, mediolateral amplitude and anteroposterior amplitude of the CoP were examined to analyse balance. The pyramid scores were obtained from qualified judges to assess the performance. Results showed higher CoP excursions and inter-trial variability during the execution of the high difficulty pyramid. Higher judges' scores were associated with lower CoP excursions in all the pyramids regardless of the difficulty. Similarly, correlation between inter-trial variability and pyramid performance was observed, although these coefficients were lower than those reported for the relationship between CoP excursion and performance. These results suggested that CoP monitoring could help coaches and gymnasts to assess the pyramid instability more accurately.Universidad Pablo de Olavide de Sevilla. Departamento de Deporte e Informátic

    Exercise-Based Cardiac Rehabilitation in Twelve European Countries Results of the European Cardiac Rehabilitation Registry

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    AIM: Results from EuroCaReD study should serve as a benchmark to improve guideline adherence and treatment quality of cardiac rehabilitation (CR) in Europe. METHODS AND RESULTS: Data from 2.054 CR patients in 12 European countries were derived from 69 centres. 76% were male. Indication for CR differed between countries being predominantly ACS in Switzerland (79%), Portugal (62%) and Germany (61%), elective PCI in Greece (37%), Austria (36%) and Spain (32%), and CABG in Croatia and Russia (36%). A minority of patients presented with chronic heart failure (4%). At CR start, most patients already were under medication according to current guidelines for the treatment of CV risk factors. A wide range of CR programme designs was found (duration 3 to 24weeks; total number of sessions 30 to 196). Patient programme adherence after admission was high (85%). With reservations that eCRF follow-up data exchange remained incomplete, patient CV risk profiles experienced only small improvements. CR success as defined by an increase of exercise capacity >25W was significantly higher in young patients and those who were employed. Results differed by countries. After CR only 9% of patients were admitted to a structured post-CR programme. CONCLUSIONS: Clinical characteristics of CR patients, indications and programmes in Europe are different. Guideline adherence is poor. Thus, patient selection and CR programme designs should become more evidence-based. Routine eCRF documentation of CR results throughout European countries was not sufficient in its first application because of incomplete data exchange. Therefore better adherence of CR centres to minimal routine clinical standards is requested

    Evaluation of Staining-Dependent Colour Changes in Resin Composites Using Principal Component Analysis

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    Colour changes in Gradia Direct (TM) composite after immersion in tea, coffee, red wine, Coca-Cola, Colgate mouthwash, and distilled water were evaluated using principal component analysis (PCA) and the CIELAB colour coordinates. The reflection spectra of the composites were used as input data for the PCA. The output data (scores and loadings) provided information about the magnitude and origin of the surface reflection changes after exposure to the staining solutions. The reflection spectra of the stained samples generally exhibited lower reflection in the blue spectral range, which was manifested in the lower content of the blue shade for the samples. Both analyses demonstrated the high staining abilities of tea, coffee, and red wine, which produced total colour changes of 4.31, 6.61, and 6.22, respectively, according to the CIELAB analysis. PCA revealed subtle changes in the reflection spectra of composites immersed in Coca-Cola, demonstrating Coca-Colas ability to stain the composite to a small degree
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