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We present possibility analysis of using Y2O2S:Er,Yb for temperature sensing. Material samples were obtained by solution combustion method. We have used pulsed laser diode excitation at 980 nm. Our analysis is based on time resolved luminescence spectra acquired by a streak camera. Intensity ratios of prominent luminescence peaks were used for determining the temperature sensing curves. We compare the synthesized Y2O2S:Er,Yb material with other thermophosphors, showing its usefulness for temperature measurements up to 620 K. [ABSTRACT FROM AUTHOR]

In this work, we analyze optical characteristics of greater celandine (Chelidonium majus L.) ethanol solution extracts and fresh leaf samples. Optical emission of samples was measured using a pulsed laser excitation of tunable wavelengths (320–470 nm) and time-resolved detection system. Results of our analysis reveal two distinct alkaloid optical emission bands with different excitation characteristics. Chlorophyll fluorescence emission band was also detected. Time-resolved analysis of luminescent spectra shows that lifetimes of both alkaloid fluorescence bands and chlorophyll band are in nanosecond domain [ABSTRACT FROM AUTHOR]

In this study we analyze nano powder Gd2O3 doped with Er3+ and Yb3+. Material was synthesized by simple and efficient solution combustion method. The nano phosphor was optically excited at 980 nm by using pulsed laser diode. We have obtained time resolved upconversion luminescence spectra of nano powder samples of Gd2O3:Er,Yb using a streak camera and analyzed temperature dependence of erbium optical line emission intensities. The possibilities of using Gd2O3:Er,Yb for temperature sensing were analyzed by means of luminescence intensity ratio method. We show that synthesized Gd2O3:Er,Yb material is useful for temperature measurements up to 550 K. [ABSTRACT FROM AUTHOR]

Bulk samples of pseudobrookite with an orthorhombic crystal structure were prepared by sintering a mixture of starting hematite and anatase nano powders in the weight ratio 60:40 at three different sintering temperatures (950, 1050 and 1150 °C) resulting in different microstructures determined by SEM analysis. Humidity sensing properties of pseudobrookite were investigated by measuring changes in electrical properties at operating temperatures of 20, 40 and 60 °C in the frequency range 100 Hz-100 kHz in the relative humidity range 30-90% in a climatic chamber. At 100 Hz, and 20 °C the impedance of pseudobrookite sintered at 1150 °C reduced over 5 times in the humidity range 40-90%, and 7 times at 60 °C for pseudobrookite sintered at 950 °C. Detailed analysis of dielectric properties showed that the dielectric constant increased noticeably with increase in humidity at low frequencies. Electrical conductivity change with frequency followed the Jonscher power law, and increased with increase in relative humidity. The determined frequency constant reduced with increase in sample temperature and increase in relative humidity. The conduction mechanism can be explained using the correlated barrier hopping model. Analysis of complex impedance using an equivalent circuit showed the dominant influence of grain boundaries. Low hysteresis (3.6 and 2.99%) was obtained in the 40-90% humidity range at room temperature (25 °C) for pseudobrookite sintered at 950 and 1150 °C. [ABSTRACT FROM AUTHOR]

Piezoresistivity was discovered in the nineteenth century. Numerous applications of this phenomenon exist nowadays. The aim of the present paper is to explore the possibility of applying the Hubbard model to theoretical work on piezoresistivity. Results are encouraging, in the sense that numerical values of the strain gauge obtained by using the Hubbard model agree with results obtained by other methods. The calculation is simplified by the fact that it uses results for the electrical conductivity of 1D systems previously obtained within the Hubbard model by one of the present authors. [ABSTRACT FROM AUTHOR]

Background: Barrett's esophagus (BE) is the premalignant manifestation of gastroesophageal reflux disease (GERD). Radiofrequency ablation (RFA) with and without endoscopic resection (ER) is a novel treatment for BE. Methods: Here we present a single-center update of the recommendations of a recent (June 2015) interdisciplinary expert panel meeting on the management of BE with dysplasia as well as cancer-positive and cancer-negative BE. We conducted a PubMed search of studies published in 2016 and 2017 on the topic of BE and RFA. Results: Our update reconfirms that BE positive for T1a cancer as well as low- and high-grade dysplasia justifies the use of RFA ± ER, offering an 80-100% rate of BE clearance. RFA ± ER of dysplastic BE is tenfold more effective for cancer prevention when compared with surveillance. Risk factors for recurrence and follow-up treatments include baseline histopathology (dysplasia/T1a cancer), esophagitis, hiatal hernia >3 cm, smoking habits, BE segments >3 cm, and >10 years of GERD symptoms. A baseline diagnosis for dysplasia and T1a cancer should include a second expert pathologist opinion. Recent data justify the use of RFA for nondysplastic BE only in controlled clinical trials. Antireflux surgery can be offered to those with function-test-proven, GERD-symptom-positive BE before, during, or after RFA ± ER. Additionally, there is growing evidence that the intake of a sugar-rich diet is positively correlated with the development of GERD, BE, and cancer. Conclusion: RFA ± ER should be offered for dysplastic BE and T1a cancer after ER as well as for nondysplastic BE with additional risk factors in controlled trials. Antireflux surgery can be offered to patients with function-test-proven GERD-symptom-positive BE. Diet considerations should be included in the management of GERD and BE. [ABSTRACT FROM AUTHOR]

In this work we have investigated changes in dielectric properties, electrical conductivity and complex impedance of FeTiO nanopowder compacts and bulk samples as a function of elevated temperature (room to 423 K compacts, to 443 K bulk samples), frequency (100 Hz-1 MHz) and composition (starting molar ratio of FeO and TiO 1:1-PSB11 and 1:1.5-PSB115). XRD, SEM and TEM analysis of PSB11 and PSB115 powders obtained by a simple solid state process from starting hematite and anatase nanopowders confirmed the formation of nanostructured orthorhombic pseudobrookite with small amounts of excess hematite and rutile. The dielectric constant decreased with frequency and temperature for both compacts and bulk samples. Higher values were determined for bulk samples also reflecting the influence of sample composition. Change in the dielectric loss also reflected the influence of sample composition showing one maximum at high frequencies for compacts, and two maxima at room temperature for bulk samples. Complex impedance was analyzed using equivalent circuits and showed in the case of compacts the influence of both grain and grain boundary components, while in the case of bulk samples the dominant influence of grain boundaries. The temperature dependence of the determined grain and grain boundary resistance for compacts and grain boundary resistance for bulk samples was analyzed using the adiabatic small polaron hopping model enabling determination of activation energies for conduction, while the temperature dependence of relaxation times enabled determination of activation energies for relaxation. Changes in electrical conductivity for compacts and bulk samples followed Jonscher's power law. The change of the determined frequency constant with temperature showed that at elevated temperatures the quantum mechanical-tunneling model for the case of small polaron hopping explains the conduction mechanism occurring in both compacts and bulk samples. [ABSTRACT FROM AUTHOR]

Casimir forces are of fundamental interest because they originate from quantum fluctuations of the electromagnetic field. Apart from controlling this force via the optical properties of materials, a number of novel geometries have been proposed to generate repulsive and/or non-monotonic Casimir forces between bodies separated by vacuum gaps. Experimental realization of these geometries, however, is hindered by the difficulties in alignment when the bodies are brought into close proximity. Here, using an on-chip platform with integrated force sensors and actuators, we circumvent the alignment problem and measure the Casimir force between two surfaces with nanoscale protrusions. We demonstrate that the force depends non-monotonically on the displacement. At some displacements, the Casimir force leads to an effective stiffening of the nanomechanical spring. Our findings pave the way for exploiting the Casimir force in nanomechanical systems using structures of complex and non-conventional shapes. [ABSTRACT FROM AUTHOR]

In this work we have analyzed how milling starting commercial Mn-Zn powder prior to the sintering process has an influence on electrical conductivity, relative permittivity and complex impedance in the frequency range from 100 Hz to 1 GHz and relative permeability in the frequency range 1-500 MHz. Starting powders additionally were milled for 30, 60, 120 and 240 min followed by sintering disk samples between 900 and 1300 °C. Structural properties were analyzed using XRD and SEM analysis. Milling the starting powder reduced grain and crystallite size, but longer milling leads to agglomeration and consequently an inhomogeneous microstructure that was more expressed at higher sintering temperatures. Milling the starting powder improved relative permeability, reaching a maximum for samples of starting powder milled for 60 min and sintered at 1200 °C. [ABSTRACT FROM AUTHOR]

Mutual collisions and impacts of solids occur in systems of widely different scales. The aim of this paper is to present a calculation of the change of temperature which a solid target undergoes when hit by a solid impactor. As a test, the equations derived are applied to examples of laboratory experimental data, and the results are physically plausible. [ABSTRACT FROM AUTHOR]

PbTe single crystals, doped with B, were grown using the Bridgman method. Far infrared spectra were measured in the temperature range between 10 K and room temperature. The experimental spectra were numerically analyzed, and optical parameters were calculated. Local impurity modes of boron were observed at about 150 and 240 cm. For all samples, after FIR measurements, the content of boron was measured using inductively coupled plasma atomic emission spectrometry. Optical mobility of free carriers was calculated and it was the highest for the sample with only 0.014 at.% of boron in PbTe. A negative photoconductivity effect at 130 K for PbTe + B was also observed. [ABSTRACT FROM AUTHOR]

Single crystals of lead telluride doped with Nd were synthesized using the Bridgeman method. Room temperature far infrared reflectivity spectra were measured for PbTe samples with Nd content in the range 0.2–0.9 at.%. Optical reflectivity in the far infrared range was measured in the temperature range between 10 and 300 K for a highly polished PbTe sample with 0.6 at.% Nd. The experimental diagrams were numerically analyzed with a fitting procedure using a modified plasmon–phonon model. Two local modes were noted and their origin was discussed. Optical electron mobility was calculated for all analyzed samples. [ABSTRACT FROM AUTHOR]

The starting mixtures of ZnO, TiO2, and MgO (0, 1.25, and 2.5 wt.%) powders are mechanically activated in a high-energy planetary mill for 15 min and then sintered between 800 and 1100°C for 2 h. The influence of MgO addition on the structure of the samples obtained is analyzed with X-ray diffraction and infrared reflection spectroscopy. Room-temperature far-infrared reflectivity spectra of the samples doped with MgO (0, 1.25, and 2.5 wt.%) and sintered at 1100°C in the frequency range between 100 and 1200 cm–1 are measured and analyzed. Optical parameters are determined for seven oscillators belonging to the spinel structure using the four-parameter model of coupled oscillators. Born effective charges are calculated from the transversal/longitudinal splitting. [ABSTRACT FROM AUTHOR]

Far infrared reflectivity spectra of single crystal PbTe doped with Bi were measured and numerically analyzed using a fitting procedure based on a modified plasmon–phonon interaction model with two additional oscillators at about 140 and 219 cm−1 which represents local Bi impurity modes. The position of observed plasma minimum and the values of the calculated parameters were compared with the literature data for pure single crystal PbTe which shows that bismuth improved the basic properties of the host crystal a lot. [ABSTRACT FROM AUTHOR]

The use of family planning methods reduces maternal mortality, prevents unwanted and high-risk pregnancies, the need for (un)safe abortion and protects from sexually transmitted diseases. The objective of the study was to assess the use of family planning methods by women in the municipality of Nis. We applied an observational cohort study that included 1,584 women age 15–49 who lived in the municipality of Nis. Data was collected through the opinion poll examination, which took place in the municipality of Nis from February to September 2002. We found 81.9% of interviewees having sexual relations protect themselves from unwanted pregnancy permanently or occasionally; 18.1% do not. Of interviewees who do not use protection and have sexual relations, 28.1% think it harms health and 27.7% think it is unsafe. Among women who use contraceptive protection, 57.9% use traditional (unsafe) methods while 42.1% use modern methods. Interviewees who use contraception mostly choose a particular method of their own accord without consultation (52.9%); 58.2% estimate their method of contraception as partly safe, 6.8% as unsafe and 35% as completely safe. As to the reason for contraception use, 40.4% state they already have their preferred number of children, 22.4% use contraception for health reasons, 17% because they are not married, 7.6% because of poor economic condition, and other reasons are present in significantly lesser percentages. Of the interviewees, 29.3% had intentionally interrupted pregnancies. The use of family planning methods is unsatisfactory. Therefore, it is necessary to promptly begin promoting protection of reproductive health and the use of modern family planning methods as a part of the nurturing of healthy lifestyles. [ABSTRACT FROM AUTHOR]

Characterizes the role of zinc nutritional status of plants on the extent of phloem mobility of zinc. Relationship between phloem mobility of zinc and zinc efficiency of the used wheat cultivars; Absence of a link between differences in expression of zinc efficiency between and within durum and bread wheats and the translocation or distribution of foliar-applied [sup 65]zinc in roots.

Investigates the uptake of [sup 59]Fe from soluble [sup 59]Fe-humate complexes by cucumber and barley plants. Extraplasmic root iron; Iron deficiency; Indirect mechanism involving ligand exchange between water-soluble humic fraction and PS.

In this paper we study the possibility of using the synthesized nanopowder samples of Gd2Zr2O7:Eu3+ for temperature measurements by analyzing the temperature effects on its photoluminescence. The nanopowder was prepared by solution combustion synthesis method. The photoluminescence spectra used for analysis of Gd2Zr2O7:Eu3+ nano phosphor optical emission temperature dependence were acquired using continuous laser diode excitation at 405 nm. The temperature dependencies of line emission intensities of transitions from 5D0 and 5D1 energy levels to the ground state were analyzed. Based on this analysis we use the two lines intensity ratio method for temperature sensing. Our results show that the synthesized material can be efficiently used as thermographic phosphor up to 650 K. [ABSTRACT FROM AUTHOR]

In this paper we study the possibility of using the synthesized nanopowder samples of Gd2Zr2O7:Eu3+ for temperature measurements by analyzing the temperature effects on its photoluminescence. The nanopowder was prepared by solution combustion synthesis method. The photoluminescence spectra used for analysis of Gd2Zr2O7:Eu3+ nano phosphor optical emission temperature dependence were acquired using continuous laser diode excitation at 405 nm. The temperature dependencies of line emission intensities of transitions from 5D0 and 5D1 energy levels to the ground state were analyzed. Based on this analysis we use the two lines intensity ratio method for temperature sensing. Our results show that the synthesized material can be efficiently used as thermographic phosphor up to 650 K. [ABSTRACT FROM AUTHOR]

An abstract of the article "Usefulness and applicability of web-based headache diagnostic software" by A. Radojicic, M. Nikolic, J. Zidverc-Trajkovic, A. Podgorac, and N. Sternic is presented.

The mechanism of iron (Fe) uptake from the leaf apoplast into leaf mesophyll cells was studied to evaluate the putative Fe inactivation as a possible cause of Fe deficiency chlorosis. For this purpose, sunflower (Helianthus annuus L.) and faba bean plants (Vicia faba L.) were precultured with varied Fe and bicarbonate (HCO3-) supply in nutrient solution. After 2-3 weeks preculture, FeIII reduction and 59Fe uptake by leaf discs were measured in solutions with Fe supplied as citrate or synthetic chelatesin darkness. The data clearly indicate that FeIII reduction is a prerequisite for Fe uptake into leaf cells and that the Fe nutritional status of plants does not affect either process. In addition, varied supply of Fe and HCO3- to the root medium during preculture had no effect on pH of the xylem sap and leaf apoplastic fluid. A varied pH of the incubation solution had no significant effect on FeIII reduction and Fe uptake by leaf discs in the physiologically relevant pH range of 5.0-6.0 as measured inthe apoplastic leaf fluid. It is concluded that Fe inactivation in the leaf apoplast is not a primary cause of Fe deficiency chlorosis induced by bicarbonate." [ABSTRACT FROM AUTHOR]