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Aims To perform a systematic evaluation of the applicability, validity and reliability of the long PCR- RFLP of 16 S- ITS-23 S r RNA genes for bacterial genotyping using both sequences retrieved from public genome databases and the experimental data obtained on bacterial cultures. Methods and Results 3301 Full-length sequences of 16 S- ITS-23 S r RNA genes were retrieved from 885 published bacterial genomes. Copy numbers of the whole set of 16 S- ITS-23 S r RNA genes per genome ranged from 1 ( n = 161) to 14 ( n = 4) with an average of 3·71. Their length varied greatly, from 4319 to 6568 bp with an average of 4952 bp. Computer-simulated RFLP analyses of the 16 S- ITS-23 S fragments flanked by the conserved primers 27 F and 2241 R suggested Msp I, Rsa I, Hha I and Taq I as the most appropriate enzymes for long PCR- RFLP analysis of the 16 S- ITS-23 S sequence. Msp I was used to screen over 900 bacterial cultures isolated from the Huguangyan Maar Lake in southern China. An experimental sequencing of 16 S r RNA genes of the isolates possessing a unique RFLP band pattern proved the broad applicability and high resolution of this approach. Conclusions These results indicate that long PCR- RFLP of 16 S- ITS-23 S r RNA genes is a potentially universal and reliable bacterial genotyping tool with a high resolution. Significance and Impact of the Study The methodology of long PCR- RFLP of 16 S- ITS-23 S r RNA genes will facilitate the exploration and tracing of cultivable microbial diversity in natural environments. [ABSTRACT FROM AUTHOR]

Abstract: The influence of DC current on the resistivity and phase transition of polycrystalline La0.7Ca0.3MnO3 has been investigated. The specific heat measurement found that charge carriers and ferromagnetic spin-wave contributions were changed after applied DC current. Applying high electric fields leads to the formation of ferromagnetic regions. The resistivity drops abruptly once the percolating current path is established. As current through the sample disappears, the larger ferromagnetic (FM) clusters, however, remain and are frozen in giving a measurable contribution to the specific heat of the system. The larger clusters should give rise to the value of spin-wave stiffness constant (D), as it is expected to increase the strength of the ferromagnetic coupling. The metallic ferromagnetic regions would make the charge carrier delocalization and attribute to specific heat linear term γ. [Copyright &y& Elsevier]

Abstract: The purpose of this experiment was to estimate the protective effects of melatonin against radiation-induced brain damages in mice induced by heavy ion beams. Kun-Ming mice were randomly divided into five groups: normal control group, irradiation control group, and three different doses of melatonin (5, 10, and 20mg/kg, i.p.) treated groups. Apart from the normal control group, the other four groups were exposed to whole-body 4.0Gy carbon ion beam irradiation (approximately 0.5Gy/min) after i.p. administration of normal saline or melatonin 1h before irradiation. The oxidative redox status of brain tissue was assessed by measurement of malondiadehyde (MDA) levels, total superoxide dismutase (T-SOD), cytosolic superoxide dismutase (Cu/ZnSOD, SOD1) and mitochondrial superoxide dismutase (MnSOD, SOD2) activities at 8h after irradiation. DNA damages were determined using the Comet assay and apoptosis and cell cycle distribution were detected by flow cytometric analyses. A dramatic dose-dependent decrease in MDA levels, tail moment, rates of tailing cells, and apoptosis, and a dose-dependent increase in T-SOD and SOD2 activities, in brain tissues in the melatonin-treated groups were detected compared with the irradiation only group. Furthermore, flow cytometric analysis demonstrated that the percentage of brain cells in the G0/G1 phase decreased significantly, while those in the S and G2/M stage increased dramatically, with mice pretreated with melatonin compared to the irradiation control group. These data indicate that melatonin has protective effects against irradiation-induced brain injury, and that its underlying protective mechanisms may relate to modulation of oxidative stress induced by heavy ionirradiation. [Copyright &y& Elsevier]

This article announces that Arun S. Mujumdar was awarded the Doctor Honoris Causa degree by Lodz Technical University for his distinguished accomplishments in the world's chemical and process engineering.

“Negative” electric-pulse-induced reversible resistance (EPIR) switching phenomenon was found in In/PCMO/Pt sandwich, in which the high resistance can be written with positive voltage pulses, and the low resistance can be reset using negative voltage pulses (the positive voltage direction is defined as going from the top electrode to the bottom electrode). This is just the opposite from the “positive” EPIR effect in Ag/PCMO/Pt sandwich, in which the high resistance can be written only with negative voltage pulses, and the low resistance can be reset using positive voltage pulses. The I–V hysteresis curves of In/PCMO/Pt and Ag/PCMO/Pt sandwiches also show opposite directions, i.e., counterclockwise and clockwise under a negative voltage region for indium and Ag electrode systems, respectively. C–V characteristics show that the barrier does not exist in Ag/PCMO/Pt sandwich, while In/PCMO/Pt sandwich exhibits an obvious Schottky-like barrier. We suggest that in the negative EPIR behavior in In/PCMO/Pt structure, the resistance states are mainly controlled changing the Schottky-like barrier at the interface with the weak effect of carrier trapping process, while the positive EPIR behavior in Ag/PCMO/Pt sandwich mainly depends on the carrier trapping process at the interface. [ABSTRACT FROM AUTHOR]

This research reports the preparation and characterization of copper nanoparticles modified by didecyl benzene sulfonate (DBS). The Cu nanoparticles’ size was determined to be 4.0 nm by transmission electron microscope (TEM). The X-ray photoelectron spectrometry (XPS) results show that there are interactions between the copper nanoparticles and DBS function group. The nonlinear optical properties were studied by the four-wave mixing method. The value of χ(3)/α0 was found to be 6.9×10-11 esu cm. [ABSTRACT FROM AUTHOR]

GaAs nanowires were grown on GaAs (100) substrates by vapor–liquid–solid growth. About 8% of these nanowires grew in <110> directions with straight, Y-branched or L-shaped morphologies. The role of strain-induced reduction in surface free energy is discussed as a possible factor contributing to the evolution of <110> nanowires. Kinking and branching is attributed to growth instabilities resulting from equivalent surface free energies for <110> growth directions. Transmission electron microscopy verified that <110> nanowires are defect free. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: Pd41.25Ni41.25P17.5 bulk metallic glasses (BMGs) undergo phase separation despite the fact that the alloy system has a negative heat of mixing. By employing the techniques of small angle X-ray scattering (SAXS), it was found that the phase separation is consistent with a spinodal mechanism. Its occurrence is attributed to unique short-range orders in the amorphous (or liquid) state of the BMGs. [Copyright &y& Elsevier]

Abstract: In this work, non-polar (1,1,−2,0) ZnO thin films have been grown on a-GaN/r-Al2O3 templates by radio-frequency magnetron sputtering. By varying the substrate temperature, the ZnO thin films were transformed from polycrystalline structure to epitaxial one on a-GaN/r-Al2O3 templates. High-quality (1,1,−2,0) ZnO epitaxial thin films were grown on the a-GaN/r-Al2O3 template at the optimized condition of 300°C, which was confirmed by X-ray diffraction. The full width at half maximum (FWHM) of the (1,1,−2,0) ω-rocking curve of the a-plane ZnO films grown on the a-GaN/r-Al2O3 template was 0.51°, indicating a small mosaicity and a low dislocation density in the ZnO film grown on the a-GaN/r-Al2O3 template. Its surface roughness observed by atomic force microscopy was about 2.32nm. Furthermore, the comparative investigation results show that the ZnO films grown on a-GaN/r-Al2O3 templates are more likely to form in the (1,1,−2,0)-orientation than those directly grown on r-sapphire. [Copyright &y& Elsevier]

Abstract: A simple sol–combustion route involving EDTA was employed to prepare nanosized MHfO3:Ce (M=Ba, Sr, or Ca) which were characterized by XRD, TEM and luminescent measurements. The as-prepared powders consist of particles with cube-like morphologies for Ce-doped BaHfO3 and SrHfO3 and uniform polyhedron-like morphology for Ce-doped CaHfO3. The average sizes of crystallites of BaHfO3:Ce, SrHfO3:Ce and CaHfO3:Ce are 48, 34 and 30.4nm, respectively. Broad emissions for nanocrystals of MHfO3:Ce (M=Ba, Sr, or Ca) resulting from Ce3+ 5d→4f transitions were observed under UV excitation, and the Stokes shift for nanocrystals of Ce-doped BaHfO3, SrHfO3 and CaHfO3 are around 9000, 7400 and 7020cm−1, respectively. [Copyright &y& Elsevier]

Elongated lamellar bands parallel to rolling plane are usually formed in γ-fiber of Ta W alloys at high strains. However, in this study, a type of lamellar bands oriented with α-fiber is formed in Ta 10 W alloy cold-rolled to 5%. Meanwhile, island equiaxed grains with special orientations can be seen in the lamellar bands. Furthermore, the lamellar bands are not homogenously distributed in the whole samples and concentrated in some elongated-grain bands. Although the lamellar bands are composed of extending planar dislocation boundaries with one or two dislocation cells across, they cannot result from incremental rotation of microbands or microshear bands, since no shear bands appear in these lamellar bands at such low strain. Therefore, the lamellar bands can be initiated by the retained elongated lamellar boundaries after annealing. They show a persistent microstructural feature as the ratio of reduction increases. As the hardness and dislocation density of the persistent lamellar bands is quite different from that of other deformed microstructures, these bands are bad for plastic deformation process. Meanwhile, protrusions at high-angle lamellar boundaries migrating to the recovered lamellar bands are observed during annealing because of the inhomogeneous dislocation microstructure. The lamellar bands can be fully eliminated when the annealing temperature reaches 1500 °C. • A type of lamellar bands oriented with the α-fiber is formed in the Ta-10W alloy at low strains. • The development of lamellar bands is related to the retained elongated lamellar boundaries after annealing. • The lamellar bands show a persistent microstructural feature as the ratio of reduction increases. • The lamellar bands can be fully eliminated when the annealing temperature reaches 1500 °C. [ABSTRACT FROM AUTHOR]

Highlights: [•] The PALE method was firstly introduced to the growth of Al0.3Ga0.7As interlayer. [•] The AlGaAs PALE interlayer could effectively eliminate APDs and suppress the Ge inter-diffusion. [•] Smooth morphology (RMS: 0.43nm) and high crystalline quality of GaAs film is achieved on 9°Ge. [•] The different kinds modes of Al0.3Ga0.7As PALE interlayers were analyzed-AlAs/GaAs and AlGa/AlGaAs. [ABSTRACT FROM AUTHOR]

Abstract: 5-Hydroxytryptamine1A (5-HT1A) receptors are expressed in the prefrontal cortical interneurons. Among these interneurons, calcium-binding protein parvalbumin (PV)-positive fast spiking (FS) interneurons play an important role in regulatory function of the prefrontal cortex. In the present study, the response of medial prefrontal cortex (mPFC) FS interneurons to the selective 5-HT1A receptor agonist 8-OH-DPAT and change in expression of 5-HT1A receptor on PV-positive neurons were examined in rats with 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta (SNc) by using extracellular recording and double-labeling immunofluorescence histochemistry. Systemic administration of 8-OH-DPAT (1–243μg/kg, i.v.) dose-dependently inhibited the mean firing rate of the FS interneurons in sham-operated and the lesioned rats, respectively. The cumulative doses producing inhibition in the lesioned rats (243μg/kg) was significantly higher than that of sham-operated rats (27μg/kg). Furthermore, the local application of 8-OH-DPAT (0.01μg) in the mPFC inhibited the FS interneurons in sham-operated rats, while having no effect on firing rate of the FS interneurons in the lesioned rats. In contrast to sham-operated rats, the lesion of the SNc in rats did not cause the change of PV-positive neurons in the prelimbic prefrontal cortex, a subregion of the mPFC, whereas the lesion of the SNc markedly reduced in percentage of PV-positive neurons expressing 5-HT1A receptors. Our results indicate that degeneration of the nigrostriatal pathway results in the decreased response of FS interneurons in the mPFC to 5-HT1A receptor stimulation, which attributes to down-regulation of 5-HT1A receptor expression in these interneurons. [Copyright &y& Elsevier]

Abstract: The 5-hydroxytryptamine (5-HT)-7 receptor began to be cloned and pharmacologically characterized close to 20 years ago. It couples positively via G-proteins to adenylyl cyclase and activation of this receptor increases neuronal excitability, and several studies have shown that degeneration of the nigrostriatal pathway leads to an impairment of 5-HT system. Here we reported that systemic and local administration of 5-HT7 receptor agonist AS 19 produced excitation, inhibition and no change in the firing rate of pyramidal neurons in medial prefrontal cortex (mPFC) of normal and 6-hydroxydopamine-lesioned rats. In normal rats, the mean response of the pyramidal neurons to AS 19 by systemic and local administration in mPFC was excitatory. The inhibitory effect by systemic administration of AS 19 was reversed by GABAA receptor antagonist picrotoxinin. Systemic administration of picrotoxinin excited all the neurons examined in normal rats, and after treatment with picrotoxinin, the local administration of AS 19 further increased the firing rate of the neurons. In the lesioned rats, systemic administration of AS 19, at the same doses, also increased the mean firing rate of the pyramidal neurons. However, cumulative dose producing excitation in the lesioned rats was higher than that of normal rats. Systemic administration of AS 19 produced inhibitory effect in the lesioned rats, which was partially reversed by picrotoxinin. The local administration of AS 19, at the same dose, did not change the firing rate of the neurons in the lesioned rats. Systemic administration of picrotoxinin and the local administration of AS 19 did not affect the firing rate of the neurons in the lesioned rats. These results indicate that activity of mPFC pyramidal neurons is regulated through activation of 5-HT7 receptor by direct or indirect action, and degeneration of the nigrostriatal pathway leads to decreased response of these neurons to AS 19, suggesting dysfunction and/or down-regulation of 5-HT7 receptor on the pyramidal neurons and GABA interneurons in the lesioned rats. [Copyright &y& Elsevier]

Abstract: The growth of GaN epilayers on AlN/Si (111) templates with thin nonlinearly composition-graded Al x Ga1−x N interlayers via metal-organic chemical vapor deposition (MOCVD) is reported in this work. The composition-graded Al x Ga1−x N interlayer was achieved by simply changing the growth condition of AlN to that of GaN layers during a fixed time. The surface morphology, crystalline quality and stress of GaN films have been investigated with different Al x Ga1−x N interlayer thickness, 280nm, 460nm, 575nm, and 750nm. It was found that the properties of GaN films are highly dependent on the Al x Ga1−x N interlayer thickness. High quality crack-free GaN films up to 1.2μm can be achieved with 460nm thick Al x Ga1−x N layer. [ABSTRACT FROM AUTHOR]

Abstract: New configurations of traveling wave thermoacoustic refrigerators driven by a traveling wave thermoacoustic engine were introduced and tested in this paper. First, the performance of the refrigerator with different-diameter inertance tubes was investigated experimentally. Then, investigation of substituting a flexible membrane attached to inertial mass for inertance tube was tested. The experimental results show that the substitution could improve the efficiency of the system and lead to a larger cooling power. So far, using helium gas as the working gas, the system could provide 340W cooling power at the temperature of −20°C with working frequency of 57Hz and average pressure of 3.0MPa. The total COP, i.e., cooling power divided by heating power, is 0.16. [ABSTRACT FROM AUTHOR]

Abstract: The changes in the firing rate and firing pattern of pyramidal neurons in medial prefrontal cortex (mPFC) and the effects of selective 5-hydroxytryptamine-1A (5-HT1A) receptor agonist (R)-(+)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT) and antagonist N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-2-pyridylcyclohexane carboxamide maleate salt (WAY-100635) on the firing activity of the neurons were studied in sham-lesioned rats and rats with 6-hydroxydopamine lesions of the substantia nigra pars compacta (SNc). The lesion of the SNc increased the firing rate of pyramidal neurons significantly compared to sham-lesioned rats, and the firing pattern of these neurons also changed significantly towards a more burst-firing. The systemic administration of 8-OH-DPAT at doses in the range of 0.5–128 μg/kg showed an excitatory-inhibitory effect on the firing rate of pyramidal neurons in mPFC of sham-lesioned rats. At lower doses, 0.5–32 μg/kg, it evoked excitation of the neurons, and at a high dose, i.e. 128 μg/kg, inhibited the activity of the neurons. In contrast to sham-lesioned rats, 8-OH-DPAT, at the same doses, showed no excitatory effect in the lesioned rats although the inhibitory phase of the effect of 8-OH-DPAT on the firing rate of pyramidal neurons in mPFC was still present. Furthermore, the local application of 8-OH-DPAT, 5 μg, in mPFC inhibited the firing rate of pyramidal neurons in sham-lesioned rats, while having no effect on firing rate in the lesioned rats. The excitatory or inhibitory effects of 8-OH-DPAT were reversed by WAY-100635, indicating that these effects are mediated by 5-HT1A receptor. Altogether, these results indicate that the lesion of the SNc leads to hyperactivity of pyramidal neurons in mPFC and the abnormality of response of these neurons to 5-HT1A receptor stimulation, suggesting that mPFC may be involved in the pathophysiology of the psychiatric disturbance of Parkinson''s disease. [Copyright &y& Elsevier]

Abstract: Several studies have shown that the 5-hydroxytryptamine (serotonin, 5-HT) system is severely affected after degeneration of nigrostriatal dopaminergic neurons. In the present study, we examined the changes in the firing rate and firing pattern of the dorsal and median raphe nuclei (DRN and MRN) 5-HT neurons, and the effect of the selective 5-HT1A receptor agonist (R)-(+)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT) and antagonist (N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-2-pyridylcyclohexane carboxamide maleate salt (WAY-100635) on the neuronal firing in rats with 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta by using extracellular recording. The unilateral lesion of the nigrostriatal pathway significantly increased the mean firing rate of DRN and MRN 5-HT neurons compared with normal rats, and the firing pattern of these neurons also changed significantly towards a more bursty one. The lower dose of 8-OH-DPAT, 4 μg/kg (cumulative doses, i.v.), completely inhibited the firing activity of all DRN and MRN 5-HT neurons examined in normal and sham rats. In contrast to normal and sham rats, only the higher doses of 8-OH-DPAT, 128 and 64 μg/kg, completely inhibited the firing rate of DRN and MRN 5-HT neurons in 6-OHDA-lesioned rats, respectively. Furthermore, the local application of 8-OH-DPAT, 1.5 μg, in the DRN completely inhibited the firing rate of 5-HT neurons in normal and sham rats, while having no effect on firing rate in the lesioned rats. Altogether, these results indicate that lesion of the nigrostriatal pathway leads to hyperactivity of DRN and MRN 5-HT neurons, suggesting the implication of the DRN and MRN in the pathophysiology of Parkinson''s disease, and the decreased response of these 5-HT neurons to 5-HT1A receptor stimulation, reflecting 5-HT1A receptor dysfunction in 6-OHDA-lesioned rats. [Copyright &y& Elsevier]