Large magnetoresistance effects in Fe3O4

We investigated the magnetoresistance (MR) of a single crystal of magnetite, Fe₃O₄. In an effort to distinguish between different contributions to the MR the samples were prepared in two different initial magnetic states, i.e. by either zero-field or by field cooling from room temperature. The different magnetic structures in this sample have a dramatic effect on the magnetoresistance: for initially zero-field-cooled conditions a negative MR of about  -20% is observed just below the Verwey transition at [Formula: see text] K. For decreasing temperature the MR increases, changes sign at  ∼78 K and reaches a record positive value of  ∼45% at around 50 K. This behavior is completely absent in the field-cooled sample. Magnetization measurements corroborate an alignment of the easy magnetization direction in applied magnetic fields below [Formula: see text] as a cause of the strong effects observed in both, magnetization and MR. Our results point to a complex interplay of structural and magnetocrystalline effects taking place upon cooling Fe₃O₄ through [Formula: see text].

[Effect of occupational lead exposure on the blood pressure of lead-exposed workers]

Objective: To investigate the effect of occupational lead exposure on blood pressure and pro-vide supportive evidence of health protection on lead - exposed workers. Methods: 612 workers (452 lead - ex-posed workers, 160 workers as control) were recruited in the battery factory. The blood lead concentration and blood pressure were detected by occupational health examination and biological monitoring. The relationship of blood lead concentration and blood pressure wasanalyzed. Results: The blood lead concentration in the exposed group (249.84±137.74) μg/L was higher than that of the control group (117.25±70.15) μg/L, and the differ-ence was statistically significant (P<0.01) . The difference of abnormal blood pressure and diastolic pressure among the exposed and the control group was statistically significant (P<0.05) . The abnormal blood pressure rate, systolic pressure rate and diastolic pressure rate in the 400~726 μg/L group was higher than that of the 6~199 μg/L and 200~399 μg/L group, and the difference was statistically significant (P<0.01) . Multiple lin-ear regression analysis showed that the influencing factors of the systolic pressure followed by sex, age, length of service and blood lead concentration, diastolic pressure followed by sex, age, smoke and blood lead concen-tration. Conclusion: These findings suggest that long - term occupational lead exposure may result in the in-crease of blood lead concentration.

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.

[SPINK3: A novel growth factor that promotes rat liver regeneration]

Serine peptidase inhibitor, Kazal type 3 (SPINK3) is a trypsin inhibitor, and also a growth factor that has an identical structure to epidermal growth factor (EGF), which could combine with epidermal growth factor receptor (EGFR) to promote cell proliferation. To shed light on the role and regulation mechanism of SPINK3 in rat liver regeneration (LR), Rat Genome 230 2.0 assay was used to detect the expression profiles of LR genes after partial hepatectomy (PH). The results showed that Spink3 was significantly up-regulated at 2-24 h and 72-168 h after PH. In the present study, RT-PCR and immunoblotting were used to validate the assay results. Ingenuity Pathway Analysis 9.0 (IPA) software was used to build the SPINK3 signaling regulating LR and analyze the possible mechanism. And then the expression of cell proliferation-associated gene Ccna2 was examined by RT-PCR in normal rat liver cell line BRL-3A in which Spink3 was overexpressed. The results showed that Ccna2 was significantly up-regulated in BRL-3A in which Spink3 was over-expressed. SPINK3 combining with EGFR accelerated cell proliferation during rat liver regeneration via P38, PKC, JAK-STAT and AKT pathways. Thus, SPINK3 was likely to promote hepatocytes proliferation in LR through P38, PKC, JAK-STAT and AKT.

Branches of the NF-κB signaling pathway regulate proliferation of oval cells in rat liver regeneration

The NF-kB (nuclear factor kB) pathway is involved in the proliferation of many cell types. To explore the mechanism of the NF-kB signaling pathway underlying the oval cell proliferation during rat liver regeneration, the Rat Genome 230 2.0 Array was used to detect expression changes of NF-kB signaling pathway-related genes in oval cells. The results revealed that the expression levels of many genes in the NF-kB pathway were significantly changed. This included 48 known genes and 16 homologous genes, as well as 370 genes and 85 homologous genes related to cell proliferation. To further understand the biological significance of these changes, an expression profile function was used to analyze the potential biological processes. The results showed that the NF-kB pathway promoted oval cell proliferation mainly through three signaling branches; the tumor necrosis factor alpha branch (TNF-a pathway), the growth factor branch, and the chemokine branch. An integrated statistics method was used to define the key genes in the NF-kB pathway. Seven genes were identified to play vital roles in the NF-kB pathway. To confirm these results, the protein content, including two key genes (TNF and FGF11) and two non-key genes (CCL2 and TNFRSF12A), were analyzed using two-dimensional gel electrophoresis and MALDI-TOF/TOF mass spectrometry. The results were generally consistent with those of the array data. To conclude, three branches and seven key genes were involved in the NF-kB signaling pathway that regulates oval cell proliferation during rat liver regeneration.

Branches of NF-κb signaling pathway regulate hepatocyte proliferation in rat liver regeneration

Previous studies have demonstrated that the nuclear factor κB (NF-κB) pathway is involved in promoting cell proliferation. To further explore the regulatory branches and their sequence in the NF-κB pathway in the promotion of hepatocyte proliferation at the transcriptional level during rat liver regeneration, Rat Genome 230 2.0 array was used to detect the expression changes of the isolated hepatocytes. We found that many genes involved in the NF-κB pathway (including 73 known genes and 19 homologous genes) and cell proliferation (including 484 genes and 104 homologous genes) were associated with liver regeneration. Expression profile function (Ep) was used to analyze the biological processes. It was revealed that the NF-κB pathway promoted hepatocyte proliferation through three branches. Several methods of integrated statistics were applied to extract and screen key genes in liver regeneration, and it indicated that eight genes may play a vital role in rat liver regeneration. To confirm the above predicted results, Ccnd1, Jun and Myc were analyzed using qRT-PCR, and the results were generally consistent with that of microarray data. It is concluded that 3 branches and 8 key genes involved in the NF-κB pathway regulate hepatocyte proliferation during rat liver regeneration.

Gene expression profiling analysis of 5-hydroxytryptamine signaling pathway in rat regenerating liver and different types of liver cells

We examined the gene expression profiles of the 5-hydroxytryptamine signaling pathway in the regenerating liver and 8 types of liver cells during rat liver regeneration, and explored expression differences in 5-hydroxytryptamine signaling pathway genes at the level of tissues and cells, as well as the role of the pathway on liver regeneration. Eight types of rat regenerating liver cells were isolated using Percoll density-gradient centrifugation and immunomagnetic bead methods. Rat Genome 230 2.0 Array was used to detect expression changes in 5-hydroxytryptamine signaling pathway genes. The results showed that 26, 47, 8, 21, 16, 19, 22, 27, and 20 genes changed significantly in hepatocytes, biliary epithelial cells, hepatic stellate cells, oval cells, sinusoidal endothelial cells, Kupffer cells, pit cells, dendritic cells, and the regenerating liver, respectively. Synthetic effects of 5-hydroxytryptamine signaling pathway genes in 8 types of liver cells showed that 26 genes were expressed significantly; the expression trends of 10 genes were the same in the regenerating liver, while others were different. Based on the gene expression profiles of the 8 types of liver cells, 5-hydroxytryptamine promoted hepatocyte proliferation through the RAS and STAT3 signaling pathways, proliferation and differentiation of sinusoidal endothelial cells through the STAT3 signaling pathway, and proliferation and apoptosis of pit cells through the AKT3 signaling pathway. There were large differences in genes involved in 5-hydroxytryptamine signaling at the tissue and cellular levels; thus, liver regeneration should be studied in-depth at the cellular level to reveal the molecular mechanism of liver regeneration.

[Studies on causes of gynecology postoperative urinary retention and its acupuncture treatment]

Urinary retention is a frequent-encountered complication after gynaecological surgery. It affects the postoperative recovery and decreases the life quality of patients. In recent years, extensive researches on causes and treatments of postoperative urinary retention are carried out in clinic. And it is approved that acupuncture treatment, which includes body needling, moxibustion, combination of acupuncture and moxibustion, acupoint injection and medication plasters, has reliable effects and less side-effects. Acupuncture treatment on postoperative urinary retention keeps developing and innovating. And it is held to have better effect when compare with western medicine.

Speed limit of the insulator-metal transition in magnetite

As the oldest known magnetic material, magnetite (Fe3O4) has fascinated mankind for millennia. As the first oxide in which a relationship between electrical conductivity and fluctuating/localized electronic order was shown, magnetite represents a model system for understanding correlated oxides in general. Nevertheless, the exact mechanism of the insulator-metal, or Verwey, transition has long remained inaccessible. Recently, three-Fe-site lattice distortions called trimerons were identified as the characteristic building blocks of the low-temperature insulating electronically ordered phase. Here we investigate the Verwey transition with pump-probe X-ray diffraction and optical reflectivity techniques, and show how trimerons become mobile across the insulator-metal transition. We find this to be a two-step process. After an initial 300 fs destruction of individual trimerons, phase separation occurs on a 1.5±0.2 ps timescale to yield residual insulating and metallic regions. This work establishes the speed limit for switching in future oxide electronics.

The role of Kupffer cells in rat liver regeneration revealed by cell-specific microarray analysis

Liver regeneration after partial hepatectomy is a process with various types of cells involved. The role of Kupffer cells (KCs) in liver regeneration is still controversial. In this study we isolated KCs from regenerating liver and conducted cell-specific microarray analysis. The results demonstrated that the controversial role of KCs in liver regeneration could be explained with the expression patterns of TGF-α, IL-6, TNF, and possibly IL-18 during liver regeneration. IL-18 may play an important role in negative regulation of liver regeneration. The functional profiles of gene expression in KCs also indicated that KC signaling might play a negative role in cell proliferation: signaling genes were down regulated before cell division. Immune response genes in KCs were also down regulated during liver regeneration, demonstrating similar expression profiles to that of hepatocytes. The expression patterns of key genes in these functional categories were consistent with the temporal functional profiles.

Symmetry of orbital order in Fe3O4 studied by Fe L(2,3) resonant x-ray diffraction

We studied the symmetry of the Fe 3d wave function in magnetite below the Verwey temperature T(V) with resonant soft-x-ray diffraction. Although the lattice structure of the low-temperature phase of Fe(3)O(4) is well described by the pseudo-orthorhombic Pmca with a slight monoclinic P2/c distortion, we find that the 3d wave function does not reflect the Pmca symmetry, and its distortion toward monoclinic symmetry is by far larger than that of the lattice. The result supports a scenario in which the Verwey transition involves the ordering of t(2g) orbitals with complex-number coefficients.

Resonant soft x-ray scattering from stepped surfaces of SrTiO3

We studied the resonant diffraction signal from stepped surfaces of SrTiO(3) at the Ti 2p → 3d (L(2,3)) resonance in comparison with x-ray absorption (XAS) and specular reflectivity data. The steps on the surface form an artificial superstructure suitable as a model system for resonant soft x-ray diffraction. A small step density on the surface is sufficient to produce a well defined diffraction peak. We determined the optical parameters of the sample across the resonance and found that the differences between the energy dependence of the x-ray absorption signal, the specular reflectivity and the step-related peak reflect the different quantities probed in these signals. When recorded at low incidence or detection angles, XAS and specular reflectivity spectra are strongly distorted by the changes of the angle of total reflection with energy. The resonant diffraction spectrum is less affected and can be used as a spectroscopic probe even in less favorable geometries.

Eight paths of ERK1/2 signalling pathway regulating hepatocyte proliferation in rat liver regeneration

Although it is known that hormones, growth factors and integrin promote hepatocyte proliferation in liver regeneration (LR) through ERK1/2 signalling pathway, reports about regulating processes of its intracellular paths in hepatocytes of LR are limited. This study aims at exploring which paths of ERK1/2 signalling pathway participate in the regulation of rat LR, especially in hepatocyte proliferation, and how they do so. In all, 14 paths and 165 genes are known to be involved in ERK1/2 signalling pathway. Of them, 161 genes are included in Rat Genome 230 2.0 Array. This array was used to detect expression changes of genes related to ERK1/2 signalling pathway in isolated hepatocytes of rat LR, showing that 60 genes were related to hepatocytes of LR. In addition, bioinformatics and systems biology methods were used to analyse the roles of 14 above paths in regenerating hepatocytes. We found that three paths, RTK→SHC→GRB2/SOS→RAS→RAF, IntegrinΒ→FAK→RAC→PAK→RAF and GΒγ→PI3KΒγ→RAC→PAK→RAF, promoted the G1 phase progression of hepatocytes by activating ERK1/2. A further four paths, Gq→PLCΒ→PKC→SRC/PYK2→GRB2/SOS→RAS→RAF, RTK→PLCγ→PKC→SRC/PYK2→GRB2/SOS→RAS→RAF, IntegrinΒ→FAK/SRC→GRB2/SOS→RAS→RAF and IntegrinΒ→FAK→RAC→PAK→RAF, advanced the cell progression of S phase and G(2)/M checkpoint by activating ERK1/2, and so did PP1/2→Mek1/2 by decreasing the negative influence on ERK1/2. At the late phase of LR, Gαs→AC→EPAC→Rap1→Raf blocked hepatocyte proliferation by decreasing the activity of ERK1/2 and so did PP1/2→Mek1/2. In summary, 60 genes and 8 paths of ERK1/2 signalling pathway regulated hepatocyte proliferation in rat LR.

Differential gene expression and functional analysis of pit cells from regenerating rat liver

Hepatic pit cells are a population of large granular lymphocytes that substantially contribute to hepatic immunity. Studies have proven that pit cells have a role in liver regeneration, but the details of the relationship between pit cells and liver regeneration is not clear at present. We subjected rats to a two-third hepatectomy; pit cells with high purity were obtained with Percoll density centrifugation and immunomagnetic bead methods, and the changes in mRNA levels in pit cells from the regenerating liver were monitored up to 168 h using a Rat Genome 230 2.0 Array composed of 25,020 distinct rat liver cDNA clones. Of the 25,020 genes analyzed, 612 known and 358 unknown genes were identified to be associated with liver regeneration. The 612 known genes are classified into up-regulation and down-regulation patterns based on the expression levels; they primarily participate in at least 23 biological activities based on gene ontology analysis. Together with gene function enrichment analysis, cytokines and a growth factor-mediated pathway in pit cells were activated at an early phase of liver regeneration; pit cell proliferation occurred from 24-72 h after liver hepatectomy; the machinery of pit cell differentiation commenced early and came into play late; an immune/inflammatory response was enhanced late. Expression pattern analysis of functionally classified genes in pit cells can give insights into the relationship between pit cells and liver regeneration.

Spin blockade, orbital occupation, and charge ordering in La1.5Sr0.5CoO4

Using Co-L2,3 and O-K x-ray absorption spectroscopy, we reveal that the charge ordering in La1.5Sr0.5CoO4 involves high spin (S=3/2) Co2+ and low spin (S=0) Co3+ ions. This provides evidence for the spin-blockade phenomenon as a source for the extremely insulating nature of the La2-xSrxCoO4 series. The associated e{g}{2} and e{g}{0} orbital occupation accounts for the large contrast in the Co-O bond lengths and, in turn, the high charge ordering temperature. Yet, the low magnetic ordering temperature is naturally explained by the presence of the nonmagnetic (S=0) Co3+ ions. From the identification of the bands we infer that La1.5Sr0.5CoO4 is a narrow band material.

Crystal-field level inversion in lightly Mn-doped Sr3Ru2O7

Sr3(Ru(1-x)Mnx)2O7, in which 4d-Ru is substituted by the more localized 3d-Mn, is studied by x-ray dichroism and spin-resolved density functional theory. We find that Mn impurities do not exhibit the same 4+ valence of Ru, but act as 3+ acceptors; the extra eg electron occupies the in-plane 3d(x2-y2) orbital instead of the expected out-of-plane 3d(3z2-r2). We propose that the 3d-4d interplay, via the ligand oxygen orbitals, is responsible for this crystal-field level inversion and the material's transition to an antiferromagnetic, possibly orbitally ordered, low-temperature state.

Determining the crystal-field ground state in rare earth heavy fermion materials using soft-x-ray absorption spectroscopy

We infer that soft-x-ray absorption spectroscopy is a versatile method for the determination of the crystal-field ground state symmetry of rare earth heavy fermion systems, complementing neutron scattering. Using realistic and universal parameters, we provide a theoretical mapping between the polarization dependence of Ce M(4,5) spectra and the charge distribution of the Ce 4f states. The experimental resolution can be orders of magnitude larger than the 4f crystal-field splitting itself. To demonstrate the experimental feasibility of the method, we investigated CePd2Si2, thereby settling an existing disagreement about its crystal-field ground state.

Direct observation of t2g orbital ordering in magnetite

Using soft-x-ray diffraction at the site-specific resonances in the Fe L2,3 edge, we find clear evidence for orbital and charge ordering in magnetite below the Verwey transition. The spectra show directly that the (001/2) diffraction peak (in cubic notation) is caused by t2g orbital ordering at octahedral Fe2+ sites and the (001) by a spatial modulation of the t2g occupation.

Expression profiles of the genes associated with metabolism and transport of amino acids and their derivatives in rat liver regeneration

Amino acids (AA) are components of protein and precursors of many important biological molecules. To address effects of the genes associated with metabolism and transport of AA and their derivatives during rat liver regeneration (LR), we firstly obtained the above genes by collecting databases data and retrieving related thesis, and then analyzed their expression profiles during LR using Rat Genome 230 2.0 array. The LR-associated genes were identified by comparing the gene expression difference between partial hepatectomy (PH) and sham-operation (SO) rat livers. It was approved that 134 genes associated with metabolism of AA and their derivatives and 26 genes involved in transport of them were LR-associated. The initially and totally expressing number of these genes occurring in initial phase of LR (0.5-4 h after PH), G0/G1 (4-6 h after PH), cell proliferation (6-66 h after PH), cell differentiation and structure-function reconstruction of liver tissue (72-168 h after PH) were respectively 76, 17, 79, 5 and 162, 89, 564, 195, illustrating that these LR-associated genes were initially expressed mainly in initial stage, and functioned in different phases. Frequencies of up-regulation and down-regulation of them being separately 564 and 357 demonstrated that genes up-regulated outnumbered those down-regulated. Categorization of their expression patterns into 22 types implied the diversity of cell physiological and biochemical activities. According to expression changes and patterns of the above-mentioned genes in LR, it was presumed that histidine biosynthesis in the metaphase and anaphase, valine metabolism in the anaphase, and metabolism of glutamate, glutamine, asparate, asparagine, methionine, alanine, leucine and aromatic amino acid almost were enhanced in the whole LR; as for amino acid derivatives, transport of neutral amino acids, urea, gamma-aminobutyric acid, betaine and taurine, metabolism of dopamine, heme, S-adenosylmethionine, thyroxine, and biosynthesis of hydroxyproline, nitric oxide, orinithine, polyamine, carnitine, selenocysteine were augmented during the entire liver restoration. Above results showed that metabolism and transport of AA and their derivates were necessary in liver regeneration.

Modelling respiratory infection control measure effects

One of the most pressing issues in facing emerging and re-emerging respiratory infections is how to bring them under control with current public health measures. Approaches such as the Wells-Riley equation, competing-risks model, and Von Foerster equation are used to prioritize control-measure efforts. Here we formulate how to integrate those three different types of functional relationship to construct easy-to-use and easy-to-interpret critical-control lines that help determine optimally the intervention strategies for containing airborne infections. We show that a combination of assigned effective public health interventions and enhanced engineering control measures would have a high probability for containing airborne infection. We suggest that integrated analysis to enhance modelling the impact of potential control measures against airborne infections presents an opportunity to assess risks and benefits. We demonstrate the approach with examples of optimal control measures to prioritize respiratory infections of severe acute respiratory syndrome (SARS), influenza, measles, and chickenpox.

Spectroscopy of stripe order in La1.8Sr0.2NiO4 using resonant soft x-ray diffraction

Strong resonant enhancements of the charge-order and spin-order superstructure-diffraction intensities in La1.8Sr0.2NiO4 are observed when x-ray energies in the vicinity of the Ni L2,3 absorption edges are used. The pronounced photon-energy and polarization dependences of these diffraction intensities allow for a critical determination of the local symmetry of the ordered spin and charge carriers. We found that not only the antiferromagnetic order but also the charge-order superstructure resides within the NiO2 layers; the holes are mainly located on in-plane oxygens surrounding a Ni2+ site with the spins coupled antiparallel in close analogy to Zhang-Rice singlets in the cuprates.

Expressed genes in regenerating rat liver after partial hepatectomy

AIM: To reveal the liver regeneration (LR) and its control as well as the occurrence of liver disease and to study the gene expression profiles of 551 genes after partial hepatectomy (PH) in regenerating rat livers.

METHODS: Five hundred and fifty-one expressed sequence tags screened by suppression subtractive hybridization were made into an in-house cDNA microarray, and the expressive genes and their expressive profiles in regenerating rat livers were analyzed by microarray and bioinformatics.

RESULTS: Three hundred of the analyzed 551 genes were up- or downregulated more than twofolds at one or more time points during LR. Most of the genes were up- or downregulated 2-5 folds, but the highest reached 90 folds of the control. One hundred and thirty-nine of them showed upregulation, 135 displayed downregulation, and up or down expression of 26 genes revealed a dependence on regenerating livers. The genes expressed in 24-h regenerating livers were much more than those in the others. Cluster analysis and generalization analysis showed that there were at least six distinct temporal patterns of gene expression in the regenerating livers, that is, genes were expressed in the immediate early phase, early phase, intermediate phase, early-late phase, late phase, terminal phase.

CONCLUSION: In LR, the number of down-regulated genes was almost similar to that of the upregulated genes; the successively altered genes were more than the rapidly transient genes. The temporal patterns of gene expression were similar 2 and 4 h, 12 and 16 h, 48 and 96 h, 72 and 144 h after PH. Microarray combined with suppressive subtractive hybridization can effectively identify the genes related to LR.

Identification of expressed genes in regenerating rat liver in 0-4-8-12 h short interval successive partial hepatectomy

AIM: To identify the genes differentially expressed in the regenerating rat liver of 0-4-8-12 h short interval successive partial hepatectomy (SISPH) and to analyze their expression profiles.

METHODS: Five hundred and fifty-one elements screened from subtractive cDNA libraries were made into a cDNA microarray (cDNA chip). Extensive gene expression analysis following 0-4-8-12 h SISPH was conducted by microarray.

RESULTS: One hundred and eighty-three elements were selected, which were either up- or down-regulated more than 2-fold at one or more time points after SISPH. Cluster analysis and generalization analysis showed that there were five distinct temporal patterns of gene expression. Eighty-six genes were unreported, associated with liver regeneration (LR).

CONCLUSION: Microarray analysis shows that the down regulated genes are much more than the up-regulated ones in SISPH; the numbers of genes expressed consistently are fewer than that expressed immediately; the genes expressed in high abundance are much fewer than that increased 2-5-fold. The comparison of SISPH with partial hepatectomy (PH) shows that the expression trends of most genes in SISPH and in PH are similar, but the expression of 43 genes is specifically altered in SISPH.

Mineralization of polyethylene glycol in aqueous solution by hydrogen peroxide with basic oxygen furnace slag

This study evaluated the dissolution behavior of basic oxygen furnace slag (BOF slag) and the performance of H2O2 with BOF slag denoted as H2O2/BOF slag process to degrade polyethylene glycol (PEG) in the aqueous solution. The concentration of total organic carbon (TOC) was chosen as a mineralization index of the degradation of PEG by the H2O2/BOF slag process. A first-order kinetic model with respect to TOC was adopted to represent the mineralization of PEG by H2O2/BOF slag process. The experimental results in this study suggested that dosages with 3.98 x 10(-4) mole min(-1) l(-1) H2O2 and 15 g l(-1) BOF slag loading in the solution at pH 2 provided the optimal operation conditions for the mineralization of PEG yielding a 75.5% treatment efficiency at 100 min reaction time. The H2O2/Fe2+ ratio was then determined to be 13.5:1.

Gene expression differences of regenerating rat liver in a short interval successive partial hepatectomy

AIM: To identify the genes expressed differentially in the regenerating rat liver in a short interval successive partial hepatectomy (SISPH), and to analyze their expression profiles.

METHODS: Five hundred and fifty-one elements selected from subtractive cDNA libraries were conformed to a cDNA microarray (cDNA chip). An extensive gene expression analysis following 0-36-72-96-144 h SISPH was performed by microarray.

RESULTS: Two hundred and sixteen elements were identified either up- or down-regulated more than 2-fold at one or more time points of SISPH. By cluster analysis and generalization analysis, 8 kinds of ramose gene expression clusters were generated in the SISPH. Of the 216 elements, 111 were up-regulated and 105 down-regulated. Except 99 unreported genes, 117 reported genes were categorized into 22 groups based on their biological functions. Comparison of the gene expression in SISPH with that after partial hepatectomy (PH) disclosed that 56 genes were specially altered in SISPH, and 160 genes were simultaneously up-regulated or down-regulated in SISPH and after PH, but in various amount and at different time points.

CONCLUSION: Genes expressed consistently are far less than that intermittently; the genes strikingly increased are much less than that increased only 2-5 fold; the expression trends of most genes in SISPH and in PH are similar, but the expression of 56 genes is specifically altered in SISPH. Microarray combined with suppressive subtractive hybridization can in a large scale effectively identify the genes related to liver regeneration.

Spin and orbital magnetic moments of Fe3O4

We present measurements of the spin and orbital magnetic moments of Fe3O4 by using SQUID and magnetic circular dichroism in soft x-ray absorption. The measurements show that Fe3O4 has a noninteger spin moment, in contrast to its predicted half-metallic feature. Fe3O4 also exhibits a large unquenched orbital moment. Calculations using the local density approximation including the Hubbard U method and the configuration interaction cluster-model suggest that strong correlations and spin-orbit interaction of the 3d electrons result in the noninteger spin and large orbital moments of Fe3O4.

Adsorption of acid dyes from aqueous solution on activated bleaching earth

In the present study, activated bleaching earth was used as clay adsorbent for an investigation of the adsorbability and adsorption kinetics of acid dyes (i.e., acid orange 51, acid blue 9, and acid orange 10) with three different molecular sizes from aqueous solution at 25 degrees C in a batch adsorber. The rate of adsorption has been investigated under the most important process parameters (i.e., initial dye concentration). A simple pseudo-second-order model has been tested to predict the adsorption rate constant, equilibrium adsorbate concentration, and equilibrium adsorption capacity by the fittings of the experimental data. The results showed that the adsorbability of the acid acids by activated bleaching earth follows the order: acid orange 51 > acid blue 9 > acid orange 10, parallel to the molecular weights and molecular sizes of the acid dyes. The adsorption removals (below 3%) of acid blue 9 and acid orange 10 onto the clay adsorbent are far lower than that (approximately 24%) of acid orange 51. Further, the adsorption kinetic of acid orange 51 can be well described by the pseudo-second-order reaction model. Based on the isotherm data obtained from the fittings of the adsorption kinetics, the Langmuir model appears to fit the adsorption better than the Freundlich model. The external coefficients of mass transfer of the acid orange 51 molecule across the boundary layer of adsorbent particle have also been estimated at the order of 10(-4)-10(-5) cm s(-1) based on the film-pore model and pseudo-second-order reaction model.

Decomposition of 2-mercaptothiazoline in aqueous solution by ozonation

This study investigates the ozonation of 2-mercaptothiazoline (2-MT). The 2-MT is one of the important organic additives for the electroplating solution of the printed wiring board industry and has been widely used as a corrosion inhibitor in many industrial processes. It is of concern for the aquatic pollution control especially in the wastewaters. Semibatch ozonation experiments in the completely stirred tank reactor are performed under various concentrations of input ozone. The concentrations of 2-MT, sulfate, and ammonium are analyzed at specified time intervals to elucidate the decomposition of 2-MT during the ozonation. In addition, the time variation of the dissolved ozone concentration (C(ALb)) is continuously monitored in the course of experiments. Total organic carbon (TOC) is chosen and measured as a mineralization index of the ozonation of 2-MT. The results indicate that the decomposition of 2-MT is efficient, while the mineralization of TOC is limited via the ozonation only. Simultaneously, the yield of sulfate with the maximum value of about 47% is characterized by the increases of TOC removal and ozone consumption. These results can provide some useful information for assessing the feasibility of the treatment of 2-MT in the aqueous solution by the ozonation.

Gene expression difference in regenerating rat liver after 0-36-40-44h short interval successive partial hepatectomy

AIM: To identify genes related to rat liver regeneration (LR) after 0-36-40-44h short interval successive partial hepatectomy (SISPH) and to analyze their action and expression profile in LR.

METHODS: A cDNA microarray containing 551 elements (liver chip) was made to analyze extensively expression changes of them in 0-36-40-44h SISPH, which were selected from subtractive cDNA libraries of the LR. Cluster analysis of these gene expression profile was performed by Genemath.

RESULTS: Among the selected 551 cDNA, 157 were up- ordown-regulated more than twofold at one or more time points. Of the 157 elements, 86 were up-regulated and 71 down-regulated, and 70 were not reported and 87 were reported, which had not been previously reported to be involved in LR. By cluster analysis and generalization analysis, 6 distinct temporal induction or suppression patterns showed that immediate induction, intermediate induction, late induction, immediate suppression, intermediate suppression, and late suppression. Comparison of the gene expression in SISPH with after PH found that 38 genes were specially altered in SISPH, and the expression trends for other 119 genes were similar between SISPH and PH, except of the various abundance at the different time points.

CONCLUSION: In 0-36-40-44h SISPH, the numbers of the up-regulated and down-regulated genes show no apparent difference. The genes expressed lately are more than that immediately, and much more than that intermediately. The genes expressed abundantly are much less than that increased 2-5 folds.

Orbital ordering in La0.5Sr1.5MnO4 studied by soft X-ray linear dichroism

We found that the conventional model of orbital-ordering of 3x(2)-r(2)/3y(2)-r(2) type in the e(g) states of La0.5Sr1.5MnO4 is incompatible with measurements of linear dichroism in the Mn 2p-edge x-ray absorption, whereas these e(g) states exhibit predominantly cross-type orbital ordering of x(2)-z(2)/y(2)-z(2). LDA+U band-structure calculations reveal that such a cross-type orbital-ordering results from a combined effect of antiferromagnetic structure, Jahn-Teller distortion, and on-site Coulomb interactions.

HSV amplicon delivery of glial cell line-derived neurotrophic factor is neuroprotective against ischemic injury

Direct intracerebral administration of glial cell line-derived neurotrophic factor (GDNF) is neuroprotective against ischemia-induced cerebral injury. Utilizing viral vectors to deliver and express therapeutic genes presents an opportunity to produce GDNF within localized regions of an evolving infarct. We investigated whether a herpes simplex virus (HSV) amplicon-based vector encoding GDNF (HSVgdnf) would protect neurons against ischemic injury. In primary cortical cultures HSVgdnf reduced oxidant-induced injury compared to the control vector HSVlac. To test protective effects in vivo, HSVgdnf or HSVlac was injected into the cerebral cortex 4 days prior to, or 3 days, after a 60-min unilateral occlusion of the middle cerebral artery. Control stroke animals developed bradykinesia and motor asymmetry; pretreatment with HSVgdnf significantly reduced such motor deficits. Animals receiving HSVlac or HSVgdnf after the ischemic insult did not exhibit any behavioral improvement. Histological analyses performed 1 month after stroke revealed a reduction in ischemic tissue loss in rats pretreated with HSVgdnf. Similarly, these animals exhibited less immunostaining for glial fibrillary acidic protein and the apoptotic marker caspase-3. Taken together, our data indicate that HSVgdnf pretreatment provides protection against cerebral ischemia and supports the utilization of the HSV amplicon for therapeutic delivery of trophic factors to the CNS.

Differential expression of the cell line-derived neurotrophic factor (GDNF) receptor GFRalpha1 in heterozygous Gfralpha1 null-mutant mice after stroke

Exogenous administration of glial cell line-derived neurotrophic factor (GDNF) reduces ischemia-induced cerebral infarction. Cerebral ischemia induces gene expression of GDNF, GDNF-receptor alpha-1 (GFRalpha-1) and c-Ret, suggesting that a GDNF signaling cascade mechanism may be involved in endogenous neuroprotection during ischemia. In the present study, we examined if this endogenous neuroprotective pathway was altered in Gfralpha-1 deficient mice. Since mice homozygous for the Gfralpha-1 deletion (-/-) die within 24 h of birth, stroke-induced changes in the levels of Gfralpha-1 mRNA were studied in Gfralpha-1 heterozygous (+/-) mice and their wild-type (+/+) littermates. The right middle cerebral artery was transiently ligated for 45 min in anesthetized mice. Animals were killed at 0, 6, 12 and 24 h after the onset of reperfusion and levels of Gfralpha-1 mRNA were measured by in situ hybridization histochemistry. Previously, we showed that Gfralpha-1 (+/-) mice are more vulnerable to focal cerebral ischemia. In the present study, we found that basal levels of GFRalpha-1 mRNA were at similar low levels in cortex and striatum in adult Gfralpha-1 (+/+) and Gfralpha-1 (+/-) mice and that ischemia/reperfusion induced up-regulation of Gfralpha-1 mRNA in the lesioned and contralateral sides of cortex and striatum in both Gfralpha-1 (+/+) and GFRalpha-1 (+/-) mice. However, the ischemia/reperfusion induction of Gfralpha-1 mRNA was significantly higher in the cortex of wild type mice, as compared to Gfralpha-1 (+/-) mice. Moreover, the increased expression of Gfralpha-1 in striatum after reperfusion occurred earlier in the GFRalpha-1 (+/+) than in the Gfralpha-1 (+/-) mice. These results indicate that after ischemia, there is a differential up-regulation of Gfralpha-1 expression in Gfralpha-1 (+/+) and Gfralpha-1 (+/-) mice. Since GDNF has neuroprotective effects, the reduced up-regulation of Gfralpha-1 in Gfralpha-1 (+/-) mice at early time points after ischemia suggests that the responsiveness to GDNF and GDNF receptor mediated neuroprotection is attenuated in these genetically modified animals and may underlie their greater vulnerability.

Adsorption of polyethylene glycol (PEG) from aqueous solution onto hydrophobic zeolite

In the present study, a hydrophobic zeolite was used as an adsorbent for the adsorption of polyethylene glycol (PEG) in water solution and electroplating solution at 25 degrees C. The adsorption capacities were determined through the adsorption isotherms in a thermostated shaker. The rate of adsorption, on the other hand, was investigated in a batch adsorber under controlled process parameters such as initial PEG concentration (30, 70, 110, 150, 200, and 300 mg x dm(-3)), agitation speed (200, 800, and 1000 rpm), and adsorbent particle size (0.72, 1.44, and 2.03 mm). A batch kinetic model, according to a pseudo-second-order mechanism, has been tested to predict the rate constant of adsorption, equilibrium adsorption capacity, time of half-adsorption, and equilibrium concentration by the fitting of the experimental data. The results of the adsorption isotherm and kinetic studies show that the adsorption process can well be described with the Langmuir and Freundlich models and the pseudo-second-order equation, respectively. Comparing the values of adsorption parameters of PEG in water solution and electroplating solution, there are no significant differences. In addition, the effective diffusion coefficient of the PEG molecule in the microporous adsorbent has been estimated at about 3.20 x 10(-8) cm(2)s(-1) based on the restrictive diffusion model.

Bone morphogenetic proteins are involved in fetal kidney tissue transplantation-induced neuroprotection in stroke rats

Both bone morphogenetic proteins (BMPs) and glial cell line-derived neurotrophic factor (GDNF) reduce ischemia-induced cerebral injury in rats. Intracerebral transplantation of fetal kidney tissue, which normally expresses BMPs and GDNF during development, reduces ischemic injury in cerebral cortex. In this study, we tested the hypothesis that BMP is involved in this neuroprotective response. Fetal kidney tissue was cut into small pieces and transplanted into cortical areas adjacent to the right middle cerebral artery (MCA) in adult rats. In situ hybridization of brain indicated that these fetal kidney transplants contained high levels of BMP-7 mRNA three days after grafting. Immunohistochemical analysis of grafted brain showed co-localization of BMP-7 and PAX-2 immunoreactivity in the graft, suggesting that these transplants contained BMP protein. Some animals were grafted with fetal kidney tissue after intraventricular administration (ICV) of the BMP antagonist noggin (1 micro g) or after vehicle, followed by MCA ligation for 60 min. Animals receiving fetal kidney tissue transplantation developed significantly less body asymmetry, as compared to stroke animals that either did not receive transplantation or received fetal kidney grafts and noggin pretreatment. Analysis of these brains after triphenyltetrazolium chloride staining showed that fetal kidney tissue transplantation reduced the volume of infarction in the cerebral cortex. Noggin pretreatment reduced the protection induced by fetal kidney grafting, although noggin itself did not cause increase in cerebral infarction. Eight hours after ischemia, brain homogenates were obtained from grafted and control animals to assay caspase-3 enzymatic activity. This analysis demonstrated that fetal kidney grafts significantly reduced ischemia-induced caspase-3 activity. Reduction of caspase-3 activity could also be antagonized by noggin pretreatment. In conclusion, our data suggest that fetal kidney transplantation reduces ischemia/reperfusion-induced cortical infarction and behavioral deficits in adult rats, which are, at least partially, mediated through the effect of BMPs from the transplants.

Protective effects of glial cell line-derived neurotrophic factor in ischemic brain injury

Glial cell line-derived neurotrophic factor (GDNF), a member of the transforming growth factor-beta (TGF-beta) superfamily, has been shown to have trophic activity on dopaminergic neurons. Recent studies indicate that GDNF can protect the cerebral hemispheres from damage induced by middle cerebral arterial ligation. We found that such neuroprotective effects are mediated through specific GDNF receptor alpha-1 (GFRalpha1). Animals with a deficiency in GFRalpha-1 have less GDNF-induced neuroprotection. Ischemia also enhances nitric oxide synthase (NOS) activity, which can be attenuated by GDNF. These.data suggest that GDNF can protect against ischemic injury through a GFRalpha-1/NOS mechanism. We also found that the receptor for GDNF, GFRalpha1, and its signaling moiety c-Ret were upregulated, starting immediately after ischemia. This upregulation suggests that activation of an endogenous neuroprotective mechanism occurs so that responsiveness of GDNF can be enhanced at very early stages during ischemia.

Sex change in the protandrous black porgy, Acanthopagrus schlegeli: a review in gonadal development, estradiol, estrogen receptor, aromatase activity and gonadotropin

Black porgy, Acanthopagrus schlegeli Bleeker, a marine protandrous hermaphrodite, is functional male for the first two years of life but begins to sexually change to female after the third year. Testicular tissue and ovarian tissue was separated by connective tissue in the bisexual gonad. This sex pattern provides a very good model to study the endocrine mechanism of sex change in fish. The annual profiles of plasma estradiol, vitellogenin and 11-ketotestosterone concentrations in males were significantly different from those in the three-year-old females. Significantly high levels of plasma estradiol during the prespawning/spawning season and low levels of plasma 11-ketotestosterone during the spawning season were observed in the inversing females. No difference of plasma testosterone levels was observed in males and females. Oral administration of estradiol stimulated high levels of gonadal aromatase activity, plasma gonadotropin II levels and sex change in the two-year-old fish. Exogenous estradiol administered for 5-6 months induced a reversible sex change in one- and two-year-old fish. The sensitive period for estradiol treatment of sex change is from early prespawning to spawning season. Implantation with testosterone for more than a year could not block the natural sex change in three-year-old fish. Exogenous aromatase inhibitors (1,4,6-androstatriene-3,17-dione or fadrozole) suppressed aromatase activity in the brain. Oral administration with aromatase inhibitors for a year further inhibited the natural sex change in three-year-old black porgy and all fish became functional male with spermiation. Estrogen receptor alpha gene in the ovarian tissue of bisexual gonad is significantly less expressed than that in the vitellogenic ovary of female on the basis of reverse-transcription polymerase-chain reaction. There was no difference in the annual profiles of the plasma gonadotropin II levels in the males and natural inversing females. Plasma gonadotropin II levels were significantly higher in estradiol-treated group than those in the control. It is concluded that estradiol, aromatase activity and estrogen receptor in the ovarian tissue play an important role in the natural and controlled sex change in black porgy. The association of gonadotropin and sex change in black porgy is not clear.

Signalling of GPI-anchored CD157 via focal adhesion kinase in MCA102 fibroblasts

CD157, a glycosylphosphatidylinositol-anchored protein, has previously been shown to mediate tyrosine phosphorylation of a 130 kDa protein (p130) in several cell lines. In this study, we have identified the p130 protein to be focal adhesion kinase (FAK or pp125(FAK)). FAK undergoes phosphorylation at Tyr-397 and Tyr-861 in intact MCA102 cells stably transfected with CD157 (MCA/CD157). MCA/CD157 cells, which displayed a rounded and compact cell morphology, exhibited a dispersed distribution, in contrast to a more closely associated and elongated spindle cell shape in the vector-transfected cells. MCA/CD157 cells proliferated at a rate 20-25% slower than the control cells. Our results demonstrate, for the first time, that FAK is a downstream signalling molecule of CD157.

Utilization of agricultural waste corn cob for the preparation of carbon adsorbent

In the present study, a series of activated carbons were prepared from agricultural waste corn cob by chemical and physical activations with potassium hydroxide (KOH)/potassium carbonate (K2CO3) and carbon dioxide (CO2). The effect of process variables such as impregnation ratio, impregnation time, activation temperature and soaking time of CO2 was studied in order to relate these preparation parameters with the physical properties of final carbon products. The resulting activated carbons were characterized by nitrogen adsorption-desorption isotherms at 77 K. The surface areas and pore volumes of carbons were estimated by the BET equation, the Langmuir equation and the t-plot method. Under the experimental conditions investigated, the main parameters in the activation of corn cob were found to be the impregnation ratio and activation temperature. The soaking time of CO2 is another important variable, which had a strong effect on the pore volume development. The BET surface area and total pore volume were as large as about 2000 m2/g and about 1.0 cm3/g, respectively. This study showed that the activation of agricultural waste corn cob with KOH/K2CO3 and CO2 was suitable for the preparation of large-surface-area activated carbons.

Bone morphogenetic protein-6 reduces ischemia-induced brain damage in rats

BACKGROUND AND PURPOSE

Bone morphogenetic protein-6 (BMP6) and its receptors are expressed in adult and fetal brain. Receptors for BMP6 are upregulated in adult brain after injury, leading to the suggestion that BMP6 is involved in the physiological response to neuronal injury. The purpose of this study was to determine whether there was a neuroprotective effect of BMP6 in vivo and in vitro.

METHODS

Lactate dehydrogenase and microtubule-associated protein-2 (MAP-2) activities were used to determine the protective effect of BMP6 against H(2)O(2) in primary cortical cultures. The neuroprotective effects of BMP6 were also studied in chloral hydrate-anesthetized rats. BMP6 or vehicle was injected into right cerebral cortex before transient right middle cerebral artery (MCA) ligation. Animals were killed for triphenyl-tetrazolium chloride staining, caspase-3 immunoreactivity and enzymatic assays, and TUNEL assay. A subgroup of animals were used for locomotor behavioral assays.

RESULTS

Application of H(2)O(2) increased lactate dehydrogenase activity and decreased the density of MAP-2(+) neurons in culture. Both responses were attenuated by BMP6 pretreatment. Complementary in vivo studies showed that pretreatment with BMP6 increased motor performance and generated less cerebral infarction induced by MCA ligation/reperfusion in rats. Pretreatment with BMP6 did not alter cerebral blood flow or physiological parameters. There was decreased ischemia-induced caspase-3 immunoreactivity, caspase-3 enzymatic activity, and density of TUNEL-positive cells in ischemic cortex in BMP6-treated animals.

CONCLUSIONS

BMP6 reduces ischemia/reperfusion injury, perhaps by attenuating molecular events underlying apoptosis.

Time course study of GFRalpha-1 expression in an animal model of stroke

Previous studies have shown that intracerebral administration of glial cell line-derived neurotrophic factor (GDNF) reduces ischemia-mediated cerebral infarction. The biological effects of GDNF are mediated by GDNF-family receptor alpha-1 (GFRalpha-1) and c-Ret. In this study, we examined the levels of expression of GFRalpha-1 and c-Ret in a rat model of stroke. Adult Sprague-Dawley rats were anesthetized with chloral hydrate. The right middle cerebral artery was ligated at its distal branch for 90 min. Animals were sacrificed at 0, 6, 12, and 24 h after reperfusion and levels of expression of GFRalpha-1 and c-Ret mRNA were determined by in situ hybridization histochemistry. We found that GFRalpha-1 mRNA was up-regulated in CA3, dentate gyrus (DG), cortex, and striatum. The peak of up-regulation in DG was 6 h after reperfusion. GFRalpha-1 mRNA levels in CA3 were gradually up-regulated over the 24-h reperfusion period. In cortex, GFRalpha-1 mRNA was up-regulated at all time points; however, the peak of up-regulation was observed at 0 and 24 h after reperfusion. In striatum, an initial up-regulation of GFRalpha-1 was found at 0 h after ischemia. In striatum, up-regulation of c-Ret mRNA was detected as early as 0 h after reperfusion. A gradual increase was found at 6, 12, and 24 h after reperfusion. In conclusion, our results indicate that there are both regional and temporal differences in up-regulation of GFRalpha-1 and c-Ret after ischemia. Since GDNF is neuroprotective, up-regulation of GFRalpha-1 and c-Ret could enhance the responsiveness to GDNF and reduce neuronal damage. The selective up-regulation of GFRalpha-1 and c-Ret in different brain areas suggests that there may be regional differences in GDNF-induced neuroprotection in stroke.

Access to prenatal, delivery, and newborn care among undocumented Hispanics in the Memphis area

The purpose of this study was to examine the prenatal, delivery, and newborn care received by undocumented Hispanics in the Memphis area. The focus was to sketch a demographic profile of this population, identify barriers encountered in obtaining prenatal, delivery and newborn care, and present a five-year projection of the demand for prenatal care for this population. Participants included 97 undocumented Hispanic women, who either were pregnant or had a baby within the past 12 months, and health care providers. Most women came from Mexico (90.7%). They tended to be young, to have low educational attainment, to be homemakers, to have a high number of members in their households, to be financially supported by their spouses, and to live at or below the poverty line. The average length of time that they had been in the United States and Memphis were 42 and 21 months respectively. With regard to access to health care, undocumented Hispanics who migrated to the Memphis area lacked adequate prenatal and delivery care, and we estimated that the demand for prenatal care in this population will increase over 60% in the next five years.

Use of dexamethasone on the prophylaxis of nausea and vomiting after tympanomastoid surgery

OBJECTIVE

The aim of this study was to evaluate the prophylactic effect of dexamethasone on postoperative nausea and vomiting (PONV) in patients undergoing tympanomastoid surgery.

STUDY DESIGN

Eighty patients (n = 40 in each of two groups) undergoing tympanomastoid surgery under general anesthesia were enrolled in this randomized, double-blind, placebo-controlled study.

METHODS

After tracheal intubation, group 1 received 10 mg dexamethasone intravenously, whereas group 2 received saline intravenously. Several parameters concerning with the occurrence of PONV were evaluated.

RESULTS

We found that dexamethasone reduced the total incidence of nausea and vomiting by 45%, with a 95% confidence interval of 26% to 64% (P <.001). Furthermore, dexamethasone reduced the incidence of vomiting episodes >4 times and the incidence of patients requiring rescue antiemetics (P <.05).

CONCLUSION

Dexamethasone at a dosage of 10 mg administered intravenously is effective in preventing PONV in patients undergoing tympanomastoid surgery.

Experimental induction of chronic borreliosis in adult dogs exposed to Borrelia burgdorferi-infected ticks and treated with dexamethasone

OBJECTIVE

To develop a method to experimentally induce Borrelia burgdorferi infection in young adult dogs.

ANIMALS

22 healthy Beagles.

PROCEDURE

All dogs were verified to be free of borreliosis. Twenty 6-month-old dogs were exposed to Borrelia burgdorferi-infected adult ticks and treated with dexamethasone for 5 consecutive days. Two dogs not exposed to ticks were treated with dexamethasone and served as negative-control dogs. Clinical signs, results of microbial culture and polymerase chain reaction (PCR) testing, immunologic responses, and gross and histologic lesions were evaluated 9 months after tick exposure.

RESULTS

Predominant clinical signs were episodic pyrexia and lameness in 12 of 20 dogs. Infection with B burgdorferi was detected in microbial cultures of skin biopsy specimens and various tissues obtained during necropsy in 19 of 20 dogs and in all 20 dogs by use of a PCR assay. All 20 exposed dogs seroconverted and developed chronic nonsuppurative arthritis. Three dogs also developed mild focal meningitis, 1 dog developed mild focal encephalitis, and 18 dogs developed perineuritis or rare neuritis. Control dogs were seronegative, had negative results for microbial culture and PCR testing, and did not develop lesions.

CONCLUSIONS AND CLINICAL RELEVANCE

Use of this technique successfully induced borreliosis in young dogs. Dogs with experimentally induced borreliosis may be useful in evaluating vaccines, chemotherapeutic agents, and the pathogenesis of borreliosis-induced arthritis.

Regulation of plasma gonadotropin II secretion by sex steroids, aromatase inhibitors, and antiestrogens in the protandrous black porgy, Acanthopagrus schlegeli Bleeker

Plasma gonadotropin II (GTH II) concentrations were significantly higher (approx. 15-20-fold) in estradiol-17beta (E(2)) treated (1.0 microg or 2.5 microg g(-1) body weight) female black porgy from days 4 to 12 compared with the control. E(2) (1 microg g(-1) wt.) had a stronger stimulation on plasma GTH II in early recrudescent phase (low GSI) males (11-fold) than in high GSI and late spermiating males (2.6-fold, P< 0.05). No effect of androgens (testosterone, T; 5alpha-dihydrotestosterone, DHT) on plasma GTH II levels was observed either sex. The levels of plasma GTH II were stimulated in 1,4,6-androstatriene-3,17-dione (ATD, 1 microg g(-1), 2 microg g(-1) body wt.) and fadrozole-treated (1 microg g(-1), 3 microg g(-1) body wt.) groups compared to control. Tamoxifen (1 microg g(-1), 3 microg g(-1) body wt.) but not enclomiphene could stimulate high GTH II levels in plasma. In another experiment of ATD in combination with T, T treatment further attenuated the ATD stimulation of plasma GTH II levels. We concluded that GTH II secretion is positively regulated by an estrogen-specific effect in female and male black porgy. Gonadal stage had significant effects on the responsiveness of GTH II to E(2) stimulation in males. A negative aromatase-dependent feedback control of plasma GTH II levels was also suggested in the protandrous black porgy, Acanthopagrus schlegeli.

Preparation of activated carbons from corn cob catalyzed by potassium salts and subsequent gasification with CO2

In the present study, granular activated carbons were prepared from agricultural waste corn cob by chemical activation with potassium salts and/or physical activation with CO2. Under the experimental conditions investigated, potassium hydroxide (KOH) and potassium carbonate (K2CO3) were effective activating agents for chemical activation during a ramping period of 10 degrees C/min and subsequent gasification (i.e., physical activation) at a soaking period of 800 degrees C. Large BET surface areas (>1,600 m2/g) of activated carbons were thus obtained by the combined activation. In addition, this study clearly showed that the porosity created in the acid-unwashed carbon products is substantially lower than that of acid-washed carbon products due to potassium salts left in the pore structure.