Strain effect on orbital and magnetic structures of Mn ions in epitaxial Nd0.35Sr0.65MnO3/SrTiO3 films using X-ray diffraction and absorption.

This study probes the temperature-dependent strain that is strongly correlated with the orbital and magnetic structures of epitaxial films of Nd0.35Sr0.65MnO3 (NSMO) that are fabricated by pulsed laser deposition with two thicknesses, 17 (NS17) and 103 nm (NS103) on SrTiO3 (STO) substrate. This investigation is probed using X-ray diffraction (XRD) and absorption-based techniques, X-ray linear dichroism (XLD) and the X-ray magnetic circular dichroism (XMCD). XRD indicates a significant shift in the (004) peak position that is associated with larger strain in NS17 relative to that of NS103 at both 30 and 300 K. Experimental and atomic multiplet simulated temperature-dependent Mn L3,2-edge XLD results reveal that the stronger strain in a thinner NS17 film causes less splitting of Mn 3d eg state at low temperature, indicating an enhancement of orbital fluctuations in the band above the Fermi level. This greater Mn 3d orbital fluctuation can be the cause of both the enhanced ferromagnetism (FM) as a result of spin moments and the reduced Néel temperature of C-type antiferromagnetism (AFM) in NS17, leading to the FM coupling of the canted-antiferromagnetism (FM-cAFM) state in NSMO/STO epitaxial films at low temperature (T = 30 K). These findings are also confirmed by Mn L3,2-edge XMCD measurements.

Origin of magnetic properties in carbon implanted ZnO nanowires.

Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.

Recombinant ApxIV protein enhances protective efficacy against Actinobacillus pleuropneumoniae in mice and pigs.

AIMS: Available bacterins, commercial or autogenous, for Actinobacillus pleuropneumoniae disease control have, thus far, shown debatable protective efficacy and only in homologous challenges. Our study sought to determine whether the addition of reombinant protein ApxIV to the multicomponent vaccine could enhance protection against homologous and heterologous challenge of A. pleuropneumoniae. METHODS AND RESULTS: The virulence of ApxI, ApxII, ApxIV and OMP were cloned and expressed using a prokaryotic system; these recombinant proteins were combined with inactivated A. pleuropneumoniae serovar 1 to formulate different multicomponent vaccines. Immune response and protective efficacy of the vaccines were evaluated in mice and pigs. A protection rate of 67% was observed against heterologous challenge in mice vaccinated with the rApxIV formulation. Piglets vaccinated with vaccine containing ApxIV produced significantly higher antibody titre and provided complete protection and reduced gross lesions by 67% when compared with the nonimmunized group after homologous challenge. Additionally, flow cytometry analysis showed significant cellular immune response. CONCLUSIONS: The results of our vaccination experiments revealed that a combination of inactivated bacteria and the recombinant antigens rApxI, rApxII, rApxIV and rOMP can provide effective protection against heterologous A. pleuropneumoniae challenge. SIGNIFICANCE AND IMPACT OF THE STUDY: The addition of ApxIV to the multicomponent vaccine could enhance homologous and heterologous protection in mice and pigs, respectively, against challenge by A. pleuropneumoniae.

A solid-state cation exchange reaction to form multiple metal oxide heterostructure nanowires.

Metal oxide nanostructures have been investigated extensively due to their wide range of physical properties; zinc oxide is one of the most promising materials. It exhibits fascinating functional properties and various types of morphologies. In particular, ZnO heterostructures have attracted great attention because their performance can be modified and further improved by the addition of other materials. In this study, we successfully transformed ZnO nanowires (NWs) into multiple ZnO/Al2O3 heterostructure NWs via a solid-state cation exchange reaction. The experiment was carried out in situ via an ultrahigh vacuum transmission electron microscope (UHV-TEM), which was equipped with a video recorder. Moreover, we analyzed the structure and composition of the heterostructure NWs by Cs-corrected STEM equipped with EDS. Based on these experimental results, we inferred a cation exchange reaction ion path model. Additionally, we investigated the defects that appeared after the cation reaction, which resulted from the remaining zinc ions. These multiple heterostructure ZnO/Al2O3 NWs exhibited excellent UV sensing sensitivity and efficiency.

Size-controllable synthesis of Bi/Bi2O3 heterojunction nanoparticles using pulsed Nd:YAG laser deposition and metal-semiconductor-heterojunction-assisted photoluminescence.

We synthesized Bi/Bi2O3 heterojunction nanoparticles at various substrate temperatures using the pulsed laser deposition (PLD) technique with a pulsed Nd:YAG laser. The Bi/Bi2O3 heterojunction nanoparticles consisted of Bi nanoparticles and Bi2O3 surface layers. The average diameter of the Bi nanoparticles and the thickness of the Bi2O3 surface layer are linearly proportional to the substrate temperature. The heterojunctions between the Bi nanoparticles and Bi2O3 surface layers, which are the metal-semiconductor heterojunctions, can strongly enhance the photoluminescence (PL) of the Bi/Bi2O3 nanoparticles, because the metallic Bi nanoparticles can provide massive free Fermi-level electrons for the electron transitions in the Bi2O3 surface layers. The enhancement of PL emission at room temperature by metal-semiconductor-heterojunctions make the Bi/Bi2O3 heterojunction nanoparticles potential candidates for use in optoelectronic nanodevices, such as light-emitting diodes (LEDs) and laser diodes (LDs).

Iron-generated hydroxyl radicals kill retinal cells in vivo: effect of ferulic acid.

Siderosis bulbi is vision threatening. An investigation into its mechanisms and management is crucial. Experimental siderosis was established by intravitreous administration of an iron particle (chronic) or FeSO(4) (acute). After siderosis, there was a significant dose-responsive reduction in eletroretinogram (a/b-wave) amplitude, and an increase in OH level, greater when caused by 24 mM FeSO(4) than that by 8 mM FeSO(4). Furthermore, the FeSO(4)-induced oxidative stress was significantly blunted by 100 microM ferulic acid (FA). Siderosis also resulted in an excessive glutamate release, increased [Ca(++)](i), and enhanced superoxide dismutase immunoreactivity. The latter finding was consistent with the Western blot result. Obvious disorganization including loss of photoreceptor outer segments and cholinergic amacrines together with a wide-spreading ferric distribution across the retina was present, which were related to the eletro-retinographic and pathologic dysfunctions. Furthermore, b-wave reduction and amacrine damage were respectively, significantly, dose-dependently, and clearly ameliorated by FA. Thus, siderosis stimulates oxidative stress, and possibly, subsequent excitotoxicity, and calcium influx, which explains why the retina is impaired electro-physiologically and pathologically. Importantly, FA protects iron toxicity perhaps by acting as a free radical scavenger. This provides an approach to the study and treatment of the iron-related disorders such as retained intraocular iron and Alzheimer disease.

Lateral self-aligned p-type In2O3 nanowire arrays epitaxially grown on Si substrates.

Lateral orientated growth of In2O3 nanowire (NW) and nanorod (NR) arrays has been achieved by a vapor transport and condensation method on (001) and (111) surfaces of Si substrates. The single crystalline In2O3 NWs and NRs were grown along [211] in parallel to the Si +/-[110] and lying in the substrate plane. The electrical measurements show that the In2O3 NWs are p-type semiconductor. By N+ doping, the resistivity of the In2O3 NWs has been tuned. The lateral self-aligned In2O3 NW and NR arrays on Si can offer some unique advantages for fabricating parallel nanodevices that can be integrated directly with silicon technology.

Nonvolatile memory devices with NiSi2/CoSi2 nanocrystals.

Metal-oxide-semiconductor structures with NiSi2 and CoSi2 nanocrystals embedded in the SiO2 layer have been fabricated. A pronounced capacitance-voltage hysteresis was observed with a memory window about 1 V under low programming voltage. The retention characteristic can be improved by using HfO2 layer as control oxide. The processing of the structure is compatible with the current manufacturing technology of semiconductor industry.

Hepatobiliary excretion of fluconazole and its interaction with cyclosporin A in rat blood and bile using microdialysis.

In order to investigate the hepatobiliary excretion of Fluconazole, we develop a rapid and sensitive method using high-performance liquid chromatography coupled with microdialysis for the simultaneous determination of unbound fluconazole in rat blood and bile. Microdialysis probes were inserted into both the jugular vein toward the right atrium and bile duct of male Sprague-Dawley rats for biological fluid sampling after administration of fluconazole at 10 mg/kg through the femoral vein. Fluconazole and dialysates were separated using a Zorbax phenyl column maintained at ambient temperature. The detection limit of fluconazole was 50 ng/ml. Biological fluid sampling thereby allowed the simultaneous determination of fluconazole levels in blood and bile. The disposition of fluconazole in the blood and bile fluid suggests that there was rapid exchange and equilibration between the blood and hepatobiliary system. In addition, to investigate the mechanism of P-glycoprotein related hepatobiliary excretion of fluconazole, we examined the drug-drug interaction of fluconazole and cyclosporin A in the aspect of pharmacokinetics. These results indicate that the plasma level of fluconazole was no different than that in bile, and that fluconazole undergoes hepatobiliary excretion, maybe unrelated to the P-glycoprotein transported system.

Effect of P-glycoprotein modulators on the pharmacokinetics of camptothecin using microdialysis.

1. By performing microdialysis, this study investigated the pharmacokinetics of unbound camptothecin in rat blood, brain and bile in the presence of P-glycoprotein mediated transport modulators (cyclosporin A, berberine, quercetin, naringin and naringenin). Pharmacokinetic parameters of camptothecin were assessed using a non-compartmental model. 2. Camptothecin rapidly crosses the blood-brain barrier (BBB) within 20 min after camptothecin administration. The disposition of camptothecin in rat bile appeared to have a slow elimination phase and a peak concentration after 20 min of camptothecin administration. The area under the concentration versus time curve (AUC) for camptothecin in bile significantly surpassed that in blood, suggesting active transport of hepatobiliary excretion. 3. In the presence of cyclosporin A camptothecin AUC, in the brain, was significantly elevated but no significant change in the presence of berberine, quercetin, naringin and naringenin. 4. With treatment by smaller doses of quercetin (0.1 mg x kg(-1)), naringin (10 mg x kg(-1)) and naringenin (10 mg x kg(-1)), they significantly diminished the camptothecin AUC in bile, but was not altered by the treatment of berberine (20 mg x kg(-1)), a higher dose of quercetin (10 mg x kg(-1)), and cyclosporin A treated (20 mg x kg(-1)) and pretreated groups. 5. The distribution ratio (AUC(bile)/AUC(blood)) of camptothecin in bile was decreased in the cyclosporin A, quercetin, naringin and naringenin treated groups. However, the distribution ratio in the brain was increased in the cyclosporin A groups, but was decreased in the groups treated with quercetin, naringin and naringenin. These results revealed that P-glycoprotein might modulate hepatobiliary excretion and BBB penetration of camptothecin.

Determination of unbound cefamandole in rat blood by microdialysis and microbore liquid chromatography.

To analyze unbound cefamandole in rat blood, a method combing microdialysis with microbore liquid chromatography has been developed. A microdialysis probe was inserted into the jugular vein/right atrium of male Sprague-Dawley rats to examine the unbound cefamandole level in the rat blood following cefamandole administration (50 mg/kg, i.v.). The dialysates were directly submitted to a liquid chromatographic system. Samples were eluted with a mobile phase containing acetonitrile-methanol-100 mM monosodium phosphate (pH 5.0; 15:20:65, v/v). The UV wavelength was set at 270 nm for monitoring the analyte. Using the retrograde method, at infusion concentrations of 1 microg/mL of cefamandole, the in vivo microdialysis recoveries were 55.44% for the rat blood (n = 6). Intra- and inter-assay accuracy and precision of the analyses were < or = 10% in the range of 0.1-10 microg/mL. Pharmacokinetic parameters were calculated from the recovery-corrected dialysate concentrations of cefamandole vs time data. The elimination half-life (t1/2,beta) was 21.6 +/- 1.6 min. The results suggest that the pharmacokinetics of unbound cefamandole in blood following cefamandole administration (50 mg/kg, i.v., n = 5) fit best to the two-compartmental model.

Evaluation of iliopsoas compartment disorders by computed tomography.

BACKGROUND: Iliopsoas compartment lesion frequently goes undiagnosed at clinical presentation. Therefore, even delayed diagnosis may depend on radiographic techniques. Computed tomography (CT) can play an important role in the identification and localization of these lesions. This report concerns the experience of using CT to evaluate the iliopsoas compartment disorder. METHODS: Retrospective review of CT scans for 42 patients who had abnormalities of the iliopsoas compartment revealed that inflammation was responsible in 20, hemorrhage in 8, and tumor in 14 patients. Diagnoses were proven by surgery or biopsy/aspiration in all cases except in five cases whose CT findings correlated with their clinical pictures. A comparison was made among the surgical data, the CT and plain abdominal films. In addition, a comparative evaluation of CT features was also made. RESULTS: By using a hypodense area for the diagnosis of psoas abscess, the sensitivity, specificity and accuracy of CT were 100%, 77%, and 88%, respectively. By using a diffuse involvement of the entire muscle for the diagnosis of hemorrhage, the sensitivity, specificity and accuracy of CT were 63%, 62%, and 62% respectively. By using a bone destruction for the diagnosis of tumors, the sensitivity, specificity and accuracy of CT were 79%, 39%, and 69%, respectively. Evaluation of the iliopsoas compartment lesions was 91% sensitive by CT and 40% sensitive by plain X-ray film. CONCLUSIONS: It is difficult to differentiate iliopsoas abscesses, hematomas and neoplasms without knowing the clinical history. However, when coupled with percutaneous aspiration biopsy, CT has proved to be an effective, rapid means to diagnose and guide the therapy of psoas lesions.

Sodium pertechnetate Tc 99m antral scan in the diagnosis of retained gastric antrum.

Retained gastric antrum (RGA) is a major factor in recurrent peptic ulcer. We studied 121 patients with proven anastomotic ulcers following subtotal gastrectomy and Billroth II reconstruction with sodium pertechnetate Tc 99m to determine the presence of RGA. Of the patients, 59 required surgery, 22 had RGA, and 16 had a positive scan for RGA. This noninvasive examination has 100% specificity. If RGA is identified before operation, minimal time is wasted in exploration of the abdomen, which is especially important in dealing with emergency cases. When an antral scan is negative for RGA, the surgeon is still advised to search for this condition.