Adsorption of Three Commercial Dyes onto Chitosan Beads Using Spectrophotometric Determination and a Multivariate Calibration Method

A simple and rapid analytical method for the simultaneous quantification of three commercial azo dyes—Tartrazine (TAR), Congo Red (CR), and Amido Black (AB) in water is presented. The simultaneous assessment of the individual concentration of an organic dye in mixtures using a spectrophotometric method is a difficult procedure in analytical chemistry, due to spectral overlapping. This drawback can be overcome if a multivariate calibration method such as Partial Least Squares Regression (PLSR) is used. This study presents a calibration model based on absorption spectra in the 300 - 650 nm range for a set of 20 different mixtures of dyes, followed by the prediction of the concentrations of dyes in 6 validation mixtures, randomly selected, using the PLSR method. Estimated limits of detection (LOD) were 0.106, 0.047 and 0.079 mg/L for TAR, CR, and AB, respectively, and limits of quantification (LOQ) were 0.355, 0.157 and 0.265 mg/L for TAR, CR, and AB, respectively. Quantitative determination of the three azo dyes was performed following optimized adsorption experiments onto chitosan beads of mixtures of TAR, CR and AB. Adsorption isotherm and kinetic studies were carried out, proving that the proposed PLSR method is rapid, accurate and reliable.

Comparative Study on the Surface Dose of Some Bolus Materials

In order to investigate the possibility of using different materials as bolus in radiotherapy, five samples denoted by S2 - S6 were prepared and analyzed by comparison with one available commercial bolus denoted by S1. Sample S1 was a thermoplastic material from Qfix;S2 was a moldable silicon rubber (RTV-530 from Prochima);S3 and S4 were obtained by adding micrometric particles of Al and Cu respectively (at the same mass concentration of 5.5%);S5 was another moldable silicon rubber (GSP400 from Prochima) and S6 was a mixture of GSP400 and micrometric particles of Cu (at the mass concentration of 5.5%). The measurements of normalized transmitted dose as a function of sample thickness were performed for all samples (S1 - S6) at two values of electron beam energy (6 and 9 MeV) produced by a linear accelerator VARIAN 2100SC. The results showed that the maximum of the normalized transmitted dose of manufactured samples (S2 - S6) is registered at smaller sample thicknesses than for the analyzed commercial bolus (sample S1). The smallest sample thickness corresponding to normalized maximum point dose is obtained for sample S2 (RTV-530). Measurements performed for electron beam energy of 6 and 9 MeV have proven the possibility of using the manufactured samples as bolus in radiotherapy.

Minimum Representative Size in Comparing Research Performance of Universities:the Case of Medicine Faculties in Romania

Purpose： The main goal of this study is to provide reliable comparison of performance in higher education. In this respect, we use scientometric measures associated with faculties of medicine in the six health studies universities in Romania.Design/methodology/approach： The method to estimate the minimum necessary size, proposed in in Shen et al.（2017）, is applied in this article. We collected data from the Scopus data-base for the academics of the departments of medicine within the six health studies universities in Romania during the 2009 to 2014. And two kind of statistic treatments based on that method are implemented, pair-wise comparison and one-to-the-rest comparison. All the results of these comparisons are shown.Findings： According to the results： We deem that Cluj and Tg. Mure？ have the superior and inferior performance respectively, since their reasonably small value of the minimum representative size, in either of the kinds of comparison, whichever indexes of citations, h-index, or g-index is used. we can not reliably distinguish differences among the rest of the faculties, since the quite large value of their minimum representative size.Research limitations： There is only six faculties of medicine in health studies universities in Romania are analyzed.Practical implications： Our methods of comparison play an important role in ranking data sets associated with different collective units, such as faculties, universities, institutions, based on some aggregate scores like mean and totality. Originality/value： We applied the minimum representative size to a new emprical context- that of the departments of medicine in the health studies universities in Romania.

Influence of velocity profile on calibration function of Lorentz force flowmeter

A Lorentz force flowmeter is a noncontact electromagnetic flow-measuring device based on exposing a flowing electrically conducting liquid to a magnetic field and measuring the force acting on the magnet system. The measured Lorentz force is proportional to the flow rate via a calibration coefficient which depends on the velocity distribution and magnetic field in liquid. In this paper, the influence of different velocity profiles on the calibration coefficient is investigated by using numerical simulations. The Lorentz forces are computed for laminar flows in closed and open rectangular channels, and the results are compared with the simplified case of a solid conductor moving at a constant velocity. The numerical computations demonstrate that calibration coefficients for solid bodies are always higher than for liquid metals. Moreover, it can be found that for some parameters the solid-body calibration coefficient is almost twice as high as for a liquid metal. These differences are explained by analyzing the patterns of the induced eddy currents and the spatial distributions of the Lorentz force density. The result provides a first step for evaluating the influence of the laminar velocity profiles on the calibration function of a Lorentz force flowmeter.

Termination of life! reflections on abortion and euthanasia

The article follows an analysis critical of the human rights convention from the perspective of abortion and euthanasia,bringing arguments for and against the right to life,starting at conception and to the final phase of a human being.

内蒙古鄂尔多斯高原古冰缘遗迹科学考察研究进展

冰缘遗迹(特别是冷生楔形构造及融冻褶皱)是重建古气候及第四纪晚期多年冻土环境的重要证据。内蒙古鄂尔多斯高原是我国北方地区冰缘现象最为发育的地区之一。为准确了解鄂尔多斯高原冰缘遗迹类型及其分布特征、区域冻土演化历史等,中国科学院西北生态环境资源研究院和荷兰自由大学共同组成科研小组,于2018年5—6月组织了"鄂尔多斯高原冰缘遗迹科学考察"。考察区域涉及靖边—城川—乌审旗—鄂尔多斯东胜区一带约12000km2的范围。考察内容主要包括鄂尔多斯高原冰缘遗迹类型及特征、分布区域、各类型冰缘遗迹所指示的气候条件的初步推断等。结果表明:冻融褶皱和冷生楔体构造是鄂尔多斯高原主要存在的两大类冰缘遗迹。基于本次考察中关于冰缘遗迹的分布与特征等新发现,并综合前人研究成果,初步推断:在气温极低、多年冻土非常发育的时段,有利于形成各类冷生楔状构造,如冰楔假形和大型原生砂楔等;在气候转暖、多年冻土退化,但还没有全部融化完阶段,可能形成融冻褶皱;区域性大面积分布和成群出现的融冻褶皱一般反映较暖气候环境下,多年冻土层上部已退化到一定程度。基于光释光(OSL)年代测试结果,结合冰缘遗迹的特征及其所指示的古气候环境,初步重建了鄂尔多斯5万年以来的冻土环境变化序列。区内多年冻土在多年冻土最大期(LPM,25~19ka BP)时最发育,以大面积连续多年冻土为主;之后,随气温转暖,总趋势呈退化状态,多年冻土分布逐渐变为片状→岛状→零星斑状,直至现今全部融完变为深季节冻土区。

The Principals Stress and Coping Strategies in Bedouin Schools in Israel

The purpose of this research is to investigate the principals’stress and coping strategies to deal with stress by principals in Bedouin schools in Israel.Data were collected in this research by combining a quantitative and qualitative mixed method.A quantitative research questionnaire was conducted for school principals in 36 schools,in addition to an interview with three principals based on the causes of principal stress and coping mechanisms.Research results show that the principals experiencing balance had the highest mean(M)of 3.28 and standard deviation(SD)of 1.64 on a five-point scale.Principals experiencing moderate stress was parents(M=3.10,SD=0.57)and teachers(M=3.14,SD=0.54),while workload had the lowest mean(M=2.97,SD=0.64).

New perspectives of volemic resuscitation in polytrauma patients:a review

Nowadays,fluid resuscitation of multiple trauma patients is still a challenging therapy.Existing therapies for volume replacement in severe haemorrhagic shock can lead to adverse reactions that may be fatal for the patient.Patients presenting with multiple trauma often develop hemorrhagic shock,which triggers a series of metabolic,physiological and cellular dysfunction.These disorders combined,lead to complications that significantly decrease survival rate in this subset of patients.Volume and electrolyte resuscitation is chal enging due to many factors that overlap.Poor management can lead to post-resuscitation systemic inflammation causing multiple organ failure and ultimately death.In literature,there is no exact formula for this purpose,and opinions are divided.This paper presents a review of modern techniques and current studies regarding the management of fluid resuscitation in trauma patients with hemorrhagic shock.According to the literature and from clinical experience,al aspects regarding post-resuscitation period need to be considered.Also,for every case in particular,emergency therapy management needs to be rigorously respected considering al physiological,biochemical and biological parameters.

Fermion scattering by a class of Bardeen black holes

In this study, the scattering of fermions by a class of Bardeen black holes is investigated. After obtaining the scattering modes by solving the Dirac equation in this geometry, we use the partial wave method to derive an analytical expression for the phase shifts that enter into the definitions of partial amplitudes that define the scattering cross sections and induced polarization. It is shown that, similar to Schwarzschild and Reissner-Nordstrom black holes, the phenomena of glory and spiral scattering are present.

Flat limit of the de Sitter QFT in the rest frame vacuum

The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the traditional adiabatic vacuum and in the new rest frame vacuum we proposed recently,in which the frequencies are separated in the rest frames as in special relativity.It is shown that only in the rest frame vacuum can the Minkowskian flat limit be reached naturally fbr any momentum,whereas in the adiabatic vacuum,this limit remains undefined in rest frames in which the momentum vanishes.An important role is played by the phases of the fundamental solutions in the rest frame vacuum,which must be regularized to obtain the desired Minkowskian flat limits.This procedure fixes the phases of the scalar mode functions and Dirac spinors,resulting in their definitive expressions derived here.The physical consequenee is that,in the rest frame vacuum,the flat limits of the oneparticle operators are simply the corresponding operators of special relativity.

Scattering of massless fermions by Schwarzschild and Reissner-Nordstrm black holes

We study the scattering of massless Dirac fermions by Schwarzschild and Reissner-Nordstrm black holes. This is done by applying partial wave analysis to the scattering modes obtained after solving the massless Dirac equation in the asymptotic regions of the two black hole geometries. We successfully obtain analytic phase shifts, with the help of which the scattering cross section is computed. The glory and spiral scattering phenomena are shown to be present, as in the case of massive fermion scattering by black holes.

Perovskite type lanthanum manganite：Morpho-structural analysis and electrical investigations

Perovskite-type oxides of LaMnO3 were synthesized by means of the sol-gel method, in the presence of citric acid as gelling agent. The precursors used were Mn（NO3）2·H2O, La2O3, and NaOH,mixed in the stoichiometric ratio to obtain perovskite materials. The obtained gel was heat-treated at 400, 600 and 800 ℃ respectively, for 6 h. X-ray diffraction and FT-IR spectroscopy were used to analyze the phase transformation as a function of temperature, and the Rietveld refinement was used in order to characterize the materials obtained structurally. The average crystallite size of the products was calculated from XRD data and the average particle size was measured from the TEM micrographs. At 600 ℃, the synthesized compound is well-crystallized, showcases a perovskite structure（Pm-3m space group）, and exhibits uniform and homogeneous hexagonally-shaped particles, with sizes in the 20-50 nm range.Complex impedance measurements in the 20-2 × 10^6 Hz frequency range were carried out at different temperatures（26-115 ℃）, and the electrical conduction mechanism is discussed.

分立空间低维纳米尺度系统

当前受到普遍关注的一些重要的研究方向，如外场作用下晶格上的电子、量子光学、量子电子学、神经网络、信号处理、介观系统以及超晶格等，都涉及到分立空间的量子系统。近一、二十年，在紧束缚固态物理学与分立的和q——变形方程的理论进展之间的相互推动，

First order QED processes in a spatially flat FLRW space-time with a Milne-type scale factor

The quantum electrodynamics(QED)in a spatially flat(1+3)-dimensional Friedmann-Lema?tre-Robertson-Walker(FLRW)space-time with a Milne-type scale factor is outlined focusing on the amplitudes of the allowed processes in the first order perturbations.The definition of the transition rates is reconsidered such that an appropriate angular behavior of the probability for creation of an electron-positron pair from a photon is obtained,which has a similar rate as the creation of a photon and an electron-positron pair from vacuum.It is shown that these processes are allowed only in the first order perturbations,since the photon emission or absorption by an electron or positron are forbidden.