Spin-polarized transport in a lateral two-dimensional diluted magnetic semiconductor electron gas

The transport property of a lateral two-dimensional diluted magnetic semiconductor electron gas under a spatially periodic magnetic field is investigated theoretically. We find that the electron Fermi velocity along the modulation direction is highly spin-dependent even if the spin polarization of the carrier population is negligibly small. It turns out that this spin-polarized Fermi velocity alone can lead to a strong spin polarization of the current, which is still robust against the energy broadening effect induced by the impurity scattering.Comment: 3 pages, 3 figures, submitted to Appl. Phys. Let

Photoelectric measurement of blood flow during hemodialysis

Accurate measurements of blood flow rate during hemodialysis are essential for determinations of hemodialyzer performance. Despite the availability of a variety of electronic blood flow meters, use of such instruments for determination of blood flow in hemodialysis has never been satisfactory, a situation caused by such factors as the need to recalibrate frequently, the necessity of incorporating transducers into the dialyzer blood circuit and the effect which variables such as hematocrit may have on the accuracy of determination. Furthermore, such devices are expensive and often require the periodic services of an electronics specialist to maintain them in an operable condition.An alternative technique for measuring flow rate in the extracorporeal blood tubing consists of timing the passage of an injected air bubble between two points in the tubing. Since the advent of maintenance dialysis, the “racetrack and bubble time” technique [1] has been widely used for routine determinations of blood flow rate. Data derived from research studies in which this method of flow determination was employed have been published widely, in spite of the relative inaccuracies of the method

Interplay between s-d exchange interaction and Rashba effect: spin-polarized transport

We investigate the spin-polarized transport properties of a two-dimensional electron gas in a n-type diluted magnetic narrow gap semiconductor quantum well subjected to a perpendicular magnetic and electric field. Interesting beating patterns in the magneto resistance are found which can be tuned significantly by varying the electric field. A resonant enhancement of spin-polarized current is found which is induced by the competition between the s-d exchange interaction and the Rashba effect [Y. A. Bychkov and E. I. Rashba, J. Phys. C 17, 6039 (1984)].Comment: 4 pages, 3 figures, Appl. Phys. Lett. (in press

Synthesis of MoS2 nanoparticles using MoO3 nanobelts as precursor via a PVP-assisted hydrothermal method

The synthesis of MoS2 nanoparticles from MoO3 with a certain morphology through a surfactant-assisted hydrothermal process is described in this paper. MoO3, which has a nanobelt morphology with a width of 100-500 nm and a length from one to several micrometers, is used as the precursor, and poly(vinylpyrrolidone) (PVP) is used as the surfactant. The morphology of the resulting MoS2 nanomaterial has been characterized by the field-emission scanning electron microscope, which shows that the obtained nanoparticles have diameters ranging from 50 to 100 nm with rough surfaces. Additionally, the composition and crystallinity as well as the phase information of the produced nanoparticles have been characterized by the energy-dispersive X-ray spectrometer and X-ray diffraction. Specifically, in this process, the presence of PVP plays a crucial role for the successful fabrication of the nanoparticle morphology, which may be due to the formation of PVP micelles leading to an oriented aggregation of MoS2 nuclei. In addition, comparative experiments have been conducted and the possible reaction mechanism is proposed. (C) 2016 Elsevier B.V. All rights reserved

Effects of ytterbium ion on the growth, metabolism and membrane fluidity of Tetrahymena thermophila

Power-time curves and metabolic properties of Tetrahymena thermophila BF5 exposed to different Yb3+ stop levels were studied by ampoule method of isothermal calorimetry at 28 degrees C. Metabolic rate (r) decreased significantly while peak time (PT) increased with the increase of Yb3+ stop. These results were mainly due to the inhibition of cell growth, which corresponded to the decrease of cell number obtained by cell counting. Compared with cell counting, calorimetry was sensible, easy to use and convenient for monitoring the toxic effects of Yb3+ stop on cells and freshwater ecosystem. It was also found that cell membrane fluidity decreased significantly under the effects of Yb3+ stop, which indicated that Yb3+ could be membrane active molecules with its effect on cell membranes as fundamental aspect of its toxicity.Power-time curves and metabolic properties of Tetrahymena thermophila BF5 exposed to different Yb3+ stop levels were studied by ampoule method of isothermal calorimetry at 28 degrees C. Metabolic rate (r) decreased significantly while peak time (PT) increased with the increase of Yb3+ stop. These results were mainly due to the inhibition of cell growth, which corresponded to the decrease of cell number obtained by cell counting. Compared with cell counting, calorimetry was sensible, easy to use and convenient for monitoring the toxic effects of Yb3+ stop on cells and freshwater ecosystem. It was also found that cell membrane fluidity decreased significantly under the effects of Yb3+ stop, which indicated that Yb3+ could be membrane active molecules with its effect on cell membranes as fundamental aspect of its toxicity

Thiol-Functionalized Mesoporous Silica for Effective Trap of Mercury in Rats

The chance of exposure to heavy metal for human being rises severely today due to the increasing water contamination and air pollution. Here, we prepared a series of thiol-functionalized mesoporous silica as oral formulation for the prevention and treatment of heavy metal poisoning. The successful incorporation of thiol was verified by the FTIR spectra. SBA15-SH-10 was used for the study as it is of uniform mesopores and fine water dispersibility. In simulated gastrointestinal fluid, the thiol-functionalized mesoporous silica can selectively capture heavy metal, showing a very high affinity for inorganic mercury (II). The blood and urine mercury levels of rats fed with a diet containing Hg (II) and material were significantly lower than those of rats fed with the metal-rich diet only. On the contrary, the mercury content in fecal excretion of the treatment group increased more than twice as much as that of the control group. This result indicated that SBA15-SH-10 could effectively remove mercury (II) in vivo and the mercury loaded on SBA15-SH-10 would be excreted out. Hence, SBA15-SH-10 has potential application in preventing and treating heavy metal poisoning via digestive system

Chlorophyll a fluorescence responses of Haloxylon ammodendron seedlings subjected to progressive saline stress in the Tarim desert highway ecological shelterbelt

In order to assess the long-term impacts of saline groundwater irrigation to Haloxylon ammodendron, one of the main shrubs in the Tarim desert highway ecological shelterbelt, we irrigated the H. ammodendron seedlings with progressive saline groundwater (3-30 g L-1, simulation environment in the Tarim desert highway ecological shelterbelt) and investigated the diurnal variations of chlorophyll a (Chl a) fluorescence parameters, such as maximal quantum yield of photosystem II (PSII) photochemistry (F-v/F-m), quantum yield of photochemical energy conversion in PSII (Y-II), the apparent rate of electron transport at the PSII level (ETR), photochemical quenching coefficient (q(P)), non-photochemical quenching (NPQ), quantum yield of nonregulated non-photochemical energy loss in PSII (Y-NO) and quantum yield of regulated non-photochemical energy loss in PSII (Y-II), at approximately 2-h intervals. F-v/F-m with 5 g L-1 (S2) was lower than that with 2 g L-1 (S1) but a little higher than 20 g L-1 (S5), respectively. Under the low light [photosyntheticallyactive radiation (PAR) a parts per thousand currency sign 250 mu mol m(-2) s(-1), at 08:00, 10:00 and 20:00 h of the local time], S1 kept the lowest Y-II and the highest Y-NPQ; while under the high light (PAR a parts per thousand yen 1500 mu mol m(-2) s(-1)), the Y-II performed S1 &gt; S2 &gt; S5, and the reverse Y-NPQ; under mild light (250 mu mol m(t-2) s(-1) a parts per thousand currency sign PAR a parts per thousand currency sign 1500 mu mol m(-2) s(-1)), S1 remained the highest Y-II, no matter the light and the salinity, the similar Y-NO almost occurred basically. The results showed that the sand-binding plant H. ammodendron could regulate its energy-utilizing strategies. The S2 might be the most suitable salinity of the irrigation water for H. ammodendron in the Tarim desert highway ecological shelterbelt in the northwest of China. </div

Genetic diversity of plankton community as depicted by PCR-DGGE fingerprinting and its relation to morphological composition and environmental factors in lake donghu

To collect information about the genetic diversity of the plankton community and to study how plankton respond to environmental conditions, plankton samples were collected from five stations representing different trophic levels in a shallow, eutrophic lake (Lake Donghu), and investigated by PCR-DGGE fingerprinting. A total of 100 bands (61 of 16S rDNA bands and 39 of 18S rDNA bands) were detected. The DGGE bands unique to any single station accounted for 38% of the total bands, whereas common bands detected at all five stations accounted for only 11%. Using UPGMA clustering and MDS ordination of DGGE fingerprints, stations I and II were found to initially group together into one cluster, which was later joined by station V. Stations III and IV were isolated into two separate groups of one station each. Some differences in grouping relationships were found when analysis was completed on the basis of chemical characteristics and morphological composition, with zooplankton composition showing the greatest variability. However, the most similar stations (I and II) were always initially grouped into one cluster. Moreover, stations that exhibited the same or similar trophic level (stations III and IV), but different concentrations of heavy metals, were further differentiated by the DGGE method. Results of the present study indicated that PCR-DGGE fingerprinting was more sensitive than the traditional methods, as other studies suggested. Additionally, PCR-DGGE appears to be more appropriate for diversity characterization of the plankton community, as it is more canonical, systematic, and effective. Most importantly, fingerprinting results are more convenient for the comparative analyses between different studies. Therefore, the use of the described fingerprinting analysis may provide an operable and sensitive biomonitoring approach to identify critical, and potentially negative, stress within an aquatic ecosystem.To collect information about the genetic diversity of the plankton community and to study how plankton respond to environmental conditions, plankton samples were collected from five stations representing different trophic levels in a shallow, eutrophic lake (Lake Donghu), and investigated by PCR-DGGE fingerprinting. A total of 100 bands (61 of 16S rDNA bands and 39 of 18S rDNA bands) were detected. The DGGE bands unique to any single station accounted for 38% of the total bands, whereas common bands detected at all five stations accounted for only 11%. Using UPGMA clustering and MDS ordination of DGGE fingerprints, stations I and II were found to initially group together into one cluster, which was later joined by station V. Stations III and IV were isolated into two separate groups of one station each. Some differences in grouping relationships were found when analysis was completed on the basis of chemical characteristics and morphological composition, with zooplankton composition showing the greatest variability. However, the most similar stations (I and II) were always initially grouped into one cluster. Moreover, stations that exhibited the same or similar trophic level (stations III and IV), but different concentrations of heavy metals, were further differentiated by the DGGE method. Results of the present study indicated that PCR-DGGE fingerprinting was more sensitive than the traditional methods, as other studies suggested. Additionally, PCR-DGGE appears to be more appropriate for diversity characterization of the plankton community, as it is more canonical, systematic, and effective. Most importantly, fingerprinting results are more convenient for the comparative analyses between different studies. Therefore, the use of the described fingerprinting analysis may provide an operable and sensitive biomonitoring approach to identify critical, and potentially negative, stress within an aquatic ecosystem