A time-variant processing approach for the analysis of alpha and gamma MEG oscillations during flicker stimulus generated entrainment

Repetitive flicker stimulation (photic driving) offers the possibility to study the properties and coupling characteristics of stimulation-sensitive neuronal oscillators by means of the MEG/EEG analysis. With flicker frequencies in the region of the individual alpha band frequency, the dynamics of the entrainment process of the alpha oscillation, as well as the dynamics of the accompanying gamma oscillations and the coupling between the oscillations, are investigated by means of an appropriate combination of time-variant analysis methods. The Hilbert and the Gabor transformation reveal time-variant properties (frequency entrainment, phase locking, and n:m synchronization) of the entrainment process in the whole frequency range. Additionally, time-variant partial directed coherence is applied to identify ocular saccadic interferences and to study the directed information transfer between the recording sites of the simultaneously derived MEG/EEG data during the entrainment. The MEG data is the focus of this methodological study as the entrainment effects of the alpha oscillation are stronger in MEG than in the EEG. The occipital brain region (visual cortex) was mainly investigated and the dynamics of the alpha entrainment quantified. It can be shown that at the beginning of this entrainment, a transient, strongly phase-locked "40-Hz" gamma oscillation occurs.     

A STUDY ON THE OCCURRENCE OF AFLATOXIN IN RAW MILK DUE TO FEEDS

Milk and milk products are the most important group of food which carries aflatoxin to the people. Therefore, the existence of aflatoxin M₁ (AFM₁) in milk is a potential risk for public health. AFM₁ existence in milk and milk products was found in studies performed in Turkey. In this study, aflatoxin contamination was detected in 48 raw milk and 48 feed samples. Milk and feed samples, in which the positive sample rate was determined as 24%, included different levels of aflatoxin. Altogether, 20 raw milk samples (41.67%) and 15 feed samples (31.25%) contained over the level of legal limits established by the Turkish Food Codex (TFC) and the European Communities (EC) regulation in positive samples. According to these results, the milk and feed samples collected from this area constitute a potential risk for public health. The most effective way of controlling aflatoxin M₁ in milk is to reduce the contamination of aflatoxin in raw milk and feed samples. Both the producers and the consumers, as well as the government, have important obligations on this subject.     

氢化锆中氢的散射律和散射矩阵研究

从氢化锆晶体散射律的角度出发,研究了氢化锆晶体散射的特殊机理。根据氢化锆晶体散射的声学模型和光学模型给出的频谱分布,用国际通用程序ＧＡＳＫＥＴ计算了氢化锆中氢的散射律。     

Fourier transform time-of-flight mass spectrometry in an electrostatic ion beam trap

We report on the application of an electrostatic ion beam trap as a mass spectrometer. The instrument is analogous to an optical resonator; ions are trapped between focusing mirrors. The storage time is limited by the residual gas pressure and reaches up to several seconds, resulting in long ion flight paths. The oscillation of ion bunches between the mirrors is monitored by nondestructive image charge detection in a field-free region and mass spectra are obtained via Fourier transform. The principle of operation is demonstrated by measuring the mass spectrum of trapped Ar+ and Xe+ particles, produced by a standard electron impact ion source. Also, mass spectra of heavier PEGnNa+ and bradykinin ions from a pulsed MALDI ion source were obtained. The long ion flight path, combined with mass-independent charge detection, makes this system particularly interesting for the investigation of large molecules.     

通用照明市场中的高亮度LED驱动挑战暨安森美半导体解决方案

本文以LED驱动为重点,分析了通用照明市场LED驱动面临的挑战,并结合安森美半导体的高性能LED驱动解决方案,探讨了不同的LED驱动应用示例,如通过交流隔离电源为LED供电和通过宽输入范围DC—DC电源为LED供电等;最后,还介绍了能够用于需要高可靠性和持续性的LED应用中的安森美半导体LED分流保护解决方案。     

Local governments' efficiency: a systematic literature review—part I

The efficient management of the available resources in local governments has been a topic of high interest in the field of public sector. We provide an extensive and comprehensive review of the existing literature on local governments' efficiency from a global point of view, covering all articles from 1990 to August 2016. This paper is the first of two. It covers the basic aspects related to local governments' efficiency measurement not taking into account the effect of environmental conditions. First, we show a detailed overview of the studies investigating public sector efficiency across various countries, comparing the data and samples employed, and the main results obtained. Second, we describe which techniques have been used for measuring efficiency in the context of local governments. Third, we summarize the inputs and outputs used. Finally, we discuss some operative directions and considerations for further research in the field.     

Microphotometric techniques in intravital microcirculatory studies.

Intravital microscopic techniques were developed in order to measure plasma proteins: (1) circulating in the streaming blood of microcirculatory vessels of the exposed rat mesentery, (2) permeating the vessel wall, and (3) moving through the perivascular interstitial tissue. By means of the ultramicrospectrophotometry, the absorbance of proteins containing aromatic amino acids at 280 nm is measured. Absolute amounts of proteins in the range of picograms are measured in a circular measuring field with a diameter of 17 micrometers. Problems of calibration and of unspecific light scattering are discussed. The scanning microfluorometry makes use of the fluorescent labelling of the plasma proteins. Interstitial tissue with a capillary vessel containing labelled proteins is measured at high speed. A motor-driven object stage synchronized with a measuring system uses scanning lines to traverse the tissue. The data are then processed by a computer. In this way we get continuous quantitative information about the dynamics of protein permeability, starting from time zero. The measuring of the fluorescence intensity and the speed of the fluorometric system are further improved by a computerized 10 kHz scanning device.     

复合钒钼酸干凝胶薄膜的制备及其湿敏特性研究

以V2O5 和Mo粉为起始物质,通过溶胶-凝胶法制备了复合钒钼酸(H2V9Mo3O32.3·nH2O)干凝胶薄膜,薄膜为层状结构,V和Mo分别以V5 和Mo6 存在;在11%～95%RH的范围内,复合钒钼酸干凝胶薄膜具有很好的湿敏特性,响应、恢复时间分别为6s和15s,感湿温度系数为0.5%RH/℃.     

Classification of coagulase-negative staphylococci isolated from urologic diseases

A total of 174 strains of coagulase-negative staphylococci were isolated from the urine of urological patients in the USSR (Moscow) and the GDR (Wernigerode). Three schemes were used for identifying the species of the cultures (S. epidermidis and S. saprophyticus): the scheme proposed by the International Subcommittee for Taxonomy of Staphylococci and Micrococci (1976), the scheme of Digranes and Oeding (1975) and the scheme proposed by the authors of the present work. The use of the above-mentioned schemes allowed to identify 25, 33 and 68 per cent of the strains respectively. S. epidermidis prevailed among the "urological" staphylococci isolated in Moscow, and S. saprophyticus prevailed among the staphylococci isolated in Wernigerode. The insufficient effectiveness of the existing schemes for identifying the species of coagulase-negative staphylococci and the necessity of searching for new reliable biological tests are emphasized.