Miracle-dz/UniFAR-FTUs huggingface dataset:
Comparison of Boron-Doped Diamond and Glassy Carbon Electrodes for Determination of Terbinafine in Pharmaceuticals Using Differential Pulse and Square Wave Voltammetry

This paper examines the electrochemical oxidation of terbinafine with the boron doped diamond and glassy carbon electrodes. The studies were performed by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square-wave voltammetry (SWV). The supporting electrolytes, solution pH, the range of potentials, and the scan rates were optimized. Terbinafine was irreversibly oxidized in all electrolytes, yielding well-defined peaks in the positive potential range. The peak potential shifted towards less positive values as the solution pH increased. Voltammetric determination of terbinafine was performed under the optimized conditions. Using the boron doped diamond electrode, a linear relationship between current and concentration was obtained between 5.44 × 10−7 and 5.18 and 10−6 mol/L with SWV and between 7.75 · 10−7 and 8.55 · 10−6 mol/L by DPV. At the glassy carbon electrode, a linear relationship between 7.75 · 10−7 and 8.55 · 10−6 mol/L was obtained by SWV and between 7.75 · 10−7 and 1.05 · 10−5 mol/L by DPV. The sensitivity, precision, and selectivity of the procedures were evaluated. In order to check the practical application of the developed methods, the concentration of terbinafine was determined in pharmaceutical preparations.
Automated Classification and Visualization of Healthy and Diseased Hard Dental Tissues by Near-Infrared Hyperspectral Imaging

Dental caries remains one of the most prevalent chronic diseases of modern society. The initial stages of dental caries are characterized by demineralization of enamel, resulting in subclinical lesions, which are difficult to diagnose. If detected early enough, such demineralization can be arrested and reversed by noninvasive means through well-established preventive measures, such as fluoride therapy, anti-bacterial therapy, or low intensity laser irradiation. Near-infrared (NIR) hyperspectral imaging is a promising new technique for early detection of dental caries based on distinct spectral features of healthy and diseased dental tissues. In this study, we apply NIR hyperspectral imaging to classify and visualize healthy and diseased dental tissues including enamel, dentin, calculus, enamel caries, and dentin caries. For this purpose, a standardized teeth database was constructed consisting of 12 extracted human teeth with different degrees of caries lesions imaged by an NIR hyperspectral system, X-ray, and digital color camera. The color and X-ray images of teeth were presented to a clinician expert for localization of the dental tissues and classification of pathological changes, thereby obtaining the gold standard. Principal component analysis (PCA) was used for multivariate local modeling of healthy and diseased dental tissues. Finally, the dental tissues were classified by employing multiple discriminant analysis. Good agreement was observed between the resulting cross-validated classification and the gold standard with the classification sensitivity and specificity exceeding 79.8% and 93.8%, respectively. This study clearly shows that the proposed automated classification and visualization method based on NIR hyperspectral imaging has considerable diagnostic potential.
In Search of a Unified Definition of Organisational Political Behaviour: Evidence for a Multi-Level Approach

Abstract Despite thousands of years of interest, there is no standardised definition of organisational politics. This paper attempts to integrate different accounts of organisational politics through the development of a multi-level definition. A two-stage field study showed that political activities observed in the workplace can be fully captured by defining organisational politics relative to organisational efficiency at the level of the organisation, the group and the individual.
Using Maimonides' Rule to Estimate the Effect of Class Size on Student Achievement

The effect of class size on student achievement has long been of concern to educators, parents, and scholars. In Israeli public schools today, class size is partly determined using a rule proposed by Maimonides in the 12th century. This rule induces a nonlinear and non-monotonic relationship between enroll- ment size and class size. We use this relationship to construct instrumental variables estimates of the effect of class size on the test scores of Israeli 4th and 5th graders in 1991 and 3rd graders in 1992. Because the up-and-down pattern in class size induced by Maimonides' rule matches a similar pattern in test scores, the rule provides a credible source of exogenous variation for investigation of the causal effect of class size on student achievement. Our use of Maimonides' rule can be viewed as an application of Campbell's (1969) regression-discontinuity design to the class size question. The results of this application show that reductions in class size induce a significant increase in reading and math scores for 5th graders and a smaller increase in reading scores for 4th graders. In contrast, there is little evidence of any association between class size and the test scores of 3rd graders, although this finding may result from problems with the 1992 wave of the testing program. The estimates also suggest that the gains from small classes are largest for students from disadvantaged backgrounds. Besides being of metho- dological interest and providing new evidence on the class size question, these findings are of immediate policy interest in Israel where legislation to reduce the maximum class size is pending.
Cross-talk bandwidth in backward pumped fiber Raman amplifiers

We report both experimental results and numerical simulations on Raman gain and crosstalk bandwidth in three backward-pumped fiber Raman amplifiers. Dependence of crosstalk on fiber length, fiber loss coefficient, and Raman gain saturation is discussed. We show an empirical formula that relates the crosstalk bandwidth to operating parameters.
SUBADIABATIC AND SUPERADIABATIC PERFORMANCE OF A TWO-SECTION POROUS BURNER

ABSTRACT Flames may be stabilized in porous media at velocities either above or below the laminar flame speed. These two regimes are often called superadiabatic and subadiabatic, respectively. In this paper, several burners are investigated experimentally at both superadiabatic and subadiabatic conditions. The upper and lower velocity limits of stable combustion are reported. For equivalence ratios of 0.70 and below, both sub- and superadiabatic performance was seen. For both sub- and superadiabatic performance, the flame was stabilized at or near the interface between the upstream and downstream sections of porous media. The lower velocity limit for superadiabatic performance was extinction of the flame. The upper limit for superadiabatic performance was blowoff, which occurred for all burners at a flow velocity several times the adiabatic laminar flame speed, a phenomenon which is attributed to heat recirculation within the porous media. For equivalence ratios above 0.70, only subadiabatic performance was observed. The lower velocity limit occurred when the flame reached extinction. The upper velocity limit occurred when heat recirculation enhanced the laminar flame speed to a point at which the flame front propagated through the upstream section of porous media and flashed back upstream of the burner. Both the upper and lower velocity limits minimized at or near an equivalence ratio of 1.1. For equivalence ratios between 1.3 and 1.7 and flow velocities between 4 and 9 cm/s, oscillations of the flame front within the downstream section of porous media were observed.
New use of size exclusion chromatography in kinetics of mechanical degradation of polymers in solution

A new method to investigate the mechanical degradation of polymers in solution is described that uses size exclusion chromatograms of the initial polymer and of the degraded sample. The incipient parts of these chromatograms are analyzed to obtain kinetic data about degradation at the level of infinitesimal fractions. The procedure is based on the fact that mechanical degradation of the polymers is a first-order reaction and macromolecules are cleaved mostly in their central region. The rate constant and the variation in the rate constant with molecular weight are determined in a single experiment, avoiding additional fractionation steps. Moreover, the slope of the size exclusion chromatographic calibration curve is derived, opening new ways to determine polydispersities or even to make rapid calibration for unknown polymers. To verify the method, the rate constant and the molecular weight dependence of the rate constant were determined for the sonic degradation of polystyrene in toluene. The rate constant is found to vary with the square of the molecular weight, and its value is in good agreement with results reported using much more laborious methods. © 1993 John Wiley & Sons, Inc.
Surface Acoustic Wave Characteristics on ZnO/\mbYZ·LiNbO 3 Structure and Their Application to Elastic Convolver

In an effort to improve the efficiency of an elastic convolver, we discussed ways to increase the electromechanical coupling factor of the LiNbO 3 (LN) substrate. We examined, both theoretically and experimentally, the surface acoustic wave (SAW) characteristics of ZnO films formed on the +Y and -Y.planes of the YZ.LN substrates. As a result, it was clear that a larger electromechanical coupling factor, k s , can be obtained with a ZnO film on the +Y.plane than on the -Y.plane of YZ.LN substrates. The maximum value of the coupling factor obtained was 0.32, which was 2.04 times the square (k R 2 ) of the value obtained without the ZnO film. By applying the LN substrate with the ZnO film on its +Y.plane to the elastic convolver, we obtained a processing time of 7.6 μs, a 3 dB bandwidth of 44 MHz and an efficiency of -58 dBm.
The Homomorphism Structure of Classes of Graphs

We consider three aspects of homomorphisms of graphs and hypergraphs which are related to the structure of colour classes: (1) density, (2) the fractal property and (3) the generation of colour classes. In particular, we prove a density theorem for hypergraphs and show that, for connected oriented graphs, all jumps are balanced (and give an example to show that connectivity is needed here). We also show that a Hajós-type theorem holds for any colour class of undirected graphs, thus providing further evidence of the well-known ‘non-effective’ character of Hajós' theorem.
Hydrogenated amorphous carbon films having embedded nanoparticles deposited by cathodic jet carbon arc technique

This paper reports the formation and properties of hydrogenated amorphous carbon (a-C: H) films having embedded nanoparticles deposited by cathodic jet carbon arc (CJCA) technique in absence of magnetic field. The films have been characterized by XRD, HRTEM, XPS, dark conductivity, activation energy, optical band gap, residual stress, hardness, elastic modulus and plastic index parameter. The properties evaluated of a-C: H films having embedded particles have been compared with that of undoped and nitrogen doped a-C films having embedded nanoparticles deposited by CJCA technique. All the properties of a- C films studied are found to depend on the gaseous environment used during the deposition of the films. These a-C films having embedded nanoparticles act as hard coating materials.
Building‐Block Diversity in Polydopamine Underpins a Multifunctional Eumelanin‐Type Platform Tunable Through a Quinone Control Point

Rational approaches to engineering polydopamine films with tailored properties for surface coating and functionalization are currently challenged by the lack of detailed information about the polymer structure and the mechanism of buildup. Using an integrated chemical and spectroscopic approach enables the demonstration of: a) a three‐component structure of polydopamine, comprising uncyclized (catecholamine) and cyclized (indole) units, as well as novel pyrrolecarboxylic acid moieties; b) remarkable variations in the relative proportions of the cyclized and uncyclized units with starting dopamine concentration; c) the occurrence of oligomer components up to the tetramer level; d) the covalent incorporation of Tris buffer; and e) the role of dopamine quinone as a crucial control point for directing the buildup pathways and tuning the properties. The importance of the uncyclized amine‐containing units in polydopamine adhesion is also highlighted. The proper selection of substrate concentration and buffer is thus proposed as a practical means of tailoring polydopamine functionality via control of competing pathways downstream of dopamine quinone.
Dielectric properties of Ti-deficient SrTiO3-δ thin films

Ti-deficient SrTi x O 3- d thin films were prepared by high frequency magnetron sputtering. Electric transport and dielectric characterization was carried out by using plate-like capacitors with YBa 2 Cu 3 O 7- d as electrode material. Samples with x = 0.988, 0.98 and 0.89 were measured in the frequency and temperature range between 100 Hz and 100 kHz and 4.2 K and 300 K, respectively. The transport properties of the films were dominated by variable range hopping via localized states. With decreasing x the density of localized states increases nearly linearly indicating that the Ti-deficiency is primarily compensated by the formation of point defects. For low defect concentration, x > 0.89, the dielectric constant is enhanced significantly by the defect formation whereas, for x = 0.89, a very strong decrease of the polarization occurs accompanied by a drastic increase of the dielectric loss, tan d.
Alkylation of Nucleic Acids by a Model Quinone Methide

Quinone methides and related electrophiles represent a common class of intermediates that form during metabolism of drugs and xenobiotics and may lead to DNA alkylation. The intrinsic reactivity of these species has now been characterized using a stable model compound, O-(tert-butyldimethylsilyl)-2-bromomethylphenol, designed to generate an o-quinone methide in the presence of fluoride. The resulting deoxynucleoside adducts were assigned unambiguously through use of two-dimensional NMR and, in particular, heteronuclear multiple-bond connectivity (HMBC). Both purines, dG and dA, reacted at their exo-amino groups. In contrast, dC had previously been shown to react at its cyclic N3 position [Rokita, S. E. ; Yang, J.; Pande, P.; Greenberg, W. A. J. Org. Chem. 1997, 62, 3010−3012], and the relatively nonnucleophilic T remained inert under all conditions examined. Surprisingly, the efficiency of cytosine modification exceeded that of adenine and guanine by more than 10-fold in competition studies with the deoxym.
29‐Si and 27‐Al Magic‐Angle Spinning Nuclear Magnetic Resonance Study of the Thermal Transformations of Pyrophyllite

The thermal transformation of pyrophyllite was analyzed using 27-Al and 29-Si MAS-NMR spectroscopies, thermal analysis (DTA-TG), dilatometry, and X-ray diffraction techniques. Above 800°C, dehydroxylation of pyrophyllite is the origin of a broad component in the 27-Al NMR spectra which is associated with a distorted pentahedral coordination of Al. At 1000°C, tetrahedral sheet breakdown takes place and a partial segregation of amorphous SiO2 is detected by NMR spectroscopy. This process permits rearrangements of aluminum ions and favors the formation of small disordered nuclei of mullite. The 27-Al NMR signals observed at 59.5, 40.7, and 1 ppm have been assigned to 4- and 6-coordinated Al in mullite, and the 29-Si NMR signals observed at −110 and −88 ppm are assigned to well-crystallized mullite and cristobalite, respectively, formed during thermal decomposition of pyrophyllite.
Simultaneous Computational Fluid Dynamics (CFD) Simulation of the Hydrodynamics and Mass Transfer in a Partially Aerated Bubble Column

In this work, simultaneous hydrodynamics and mass-transfer computational fluid dynamics (CFD) studies in a rectangular partially aerated bubble column were conducted. The proposed transient Eulerian−Eulerian model was applied to a two-phase flow composed of polydispersed air and water. Four different kl correlations were implemented in the CFD code, and the results were compared. At superficial gas velocity values ranging from 2.4 mm/s to 21.3 mm/s, the developed flow regimes were experimentally characterized by means of visual observations, global gas holdup, plume oscillation period, and Sauter mean bubble diameter measurements. Simultaneously, the transfer of oxygen from the disperse phase to the initially deoxygenized water was characterized by the measurement of the evolution of the dissolved oxygen concentration with time. Comparison between the experimental and simulated parameters previously mentioned allows for the validation of the computational model. According to the results presented in this .
Trophic state, ecosystem efficiency and biodiversity of transitional aquatic ecosystems: analysis of environmental quality based on different benthic indicators

Estuaries and coastal lagoons are characterized by a strong spatial and temporal variability of physicochemical characteristics and productivity patterns. In these environments, the magnitude and direction of the ecological responses to inorganic nutrient increase (i.e. eutrophication) are difficult to predict. In the framework of the project, New Indicators of Trophic state and environmental quality of marine coastal ecosystems and transitional environments (NITIDA), we analysed benthic indicators of trophic state, ecosystem efficiency, and environmental quality in four different transitional environments. The trophic state of the sediments was assessed in terms of quantity and bioavailability of sediment organic C pools; ecosystem efficiency was determined in terms of the prokaryote efficiency in exploiting enzymatycally degraded organic C; environmental quality was determined in terms of meiofaunal diversity. Here, we provide a synopsis of the results obtained and a meta-analysis of the scores assessments obtained using the different ecological indicators of environmental quality and demonstrate that trophic state, ecosystem efficiency, and biodiversity in transitional ecosystems are closely linked. We conclude that the assessment of the environmental quality of transitional ecosystems should be based upon a battery of trophic state indicators and ‘sensors’ of ecosystem functioning, efficiency, and quality.
Knowledge, attitude and willingness to accept the RTS,S malaria vaccine among mothers in Abuja Nigeria

Objective To assess mothers knowledge, attitude, and practices to malaria and its prevention as well as mothers willingness to accept the RTS,S/AS01 malaria vaccine. Methods A cross-sectional study design was used to administer questionnaires to 180 mothers within six public secondary health facilities in Abuja, Nigeria. Regression analyses were used to assess the effect of maternal demographics and exposure to malaria related messages on the outcome measures. Results Knowledge of malaria preventive measures was approximately 59% (124/180). Multivariate logistic regression analyses indicated ethnicity, education and number of messages or training on malaria were associated with mothers knowledge of 3 or more preventive measures against malaria. About 30% (36/180) of respondents were aware of malaria vaccines but only four percent (7/180) had heard of RTS,S. Young maternal age (OR, 2.4; p = 0.03), self-employment (OR, 2.55; p = 0.04) and formal employment (OR, 3.74; p = 0.03) were associated with no prior knowledge of malaria vaccine. Ninety-one percent (163/180) had positive attitude to malaria vaccine and 98% (176/180) were willing to allow their child(ren) to be immunized with RTS,S despite the efficacy of the vaccine, route of administration and number of doses. Conclusion Knowledge of malaria preventive measures does not correlate with knowledge of RTS,S. Although willingness to accept RTS,S is high, consistent targeted messaging on RTS,S would be required to improve community knowledge and attitude prior to implementation to ensure maximum uptake. Keywords: knowledge, attitude, malaria prevention, RTS,S malaria vaccine, vaccine acceptance
Reduced frequency of perforin-positive CD8+ T cells in menstrual effluent of endometriosis patients compared to healthy controls

Background: Endometriosis is a widespread disease in women of reproductive age. The disease often reduces life quality of women affected by symptoms like dysmenorrhea, dyspareunia or infertility. Diagnosis remains challenging and no causal treatments exist until now. The scientific literature indicates many immunological changes like reduced cytotoxicity of natural killer cells and macrophages or altered concentrations of cytokines or cell adhesion molecules in women with endometriosis. Research has been concentrated on immunological alterations in peripheral blood, endometrial tissue and peritoneal fluid of women with endometriosis. Yet, knowledge on immunological differences in menstrual effluent is scarce. The aim of this study was to investigate menstrual effluent of hormone-free women with endometriosis in comparison to age matched healthy controls regarding selected immunological parameters. Methods: 12 women with endometriosis and 11 healthy controls were included in the study. Menstrual effluent (ME) was collected using menstrual cups over a time period of 24 h, and venous blood samples (PB) were taken. Mononuclear cells were obtained from ME (MMC) and PB (PBMC) using density gradient centrifugation and analyzed using flow cytometry. Furthermore, concentrations of cell adhesion molecules (ICAM-I and VCAM-I) and cytokines (IL-6, IL-8 and TNF-) were measured in centrifugation supernatant of ME and plasma of PB. Results: The comparison of MMC from women with endometriosis and healthy controls revealed a significantly lower frequency of perforin-positive cells among CD8+ T cells in endometriosis patients compared to healthy controls. No additional differences regarding frequencies of CD8+ or CD4+ T cells, regulatory T cells (Tregs), NK cell subsets or monocytic subsets could be detected between MMC or PBMC, of endometriosis patients and healthy controls. Comparing MMC with PBMC revealed that MMC contained significantly more B cells and significantly less T cells than PBMC. Among the T cells, the CD4/CD8 ratio was significantly higher in MMC, and Tregs were significantly less common in MMC. T cells and NK cells expressed significantly more CD69 in MMC. , NK cells of the MMC were predominantly CD56bright/CD16dim and the CD56dim NK cell subset had a low frequency of perforin+ cells, in contrast to CD56dim NK cells of PBMC, which were predominantly perforin-positive. However, NKp46 was significantly more expressed on NK cells from MMC. Finally, the endometriosis group had significantly lower plasma ICAM-I concentrations than the control group. There were no significant differences in VCAM-1, IL-6, IL-8 or TNF- between the two groups. Conclusion: MMC are distinctively different from PBMC and, thus, seem to be of endometrial origin. The CD8+ T cells from the ME were significantly less perforin-positive in endometriosis patients than in healthy controls, suggesting a reduced cytotoxic potential.