Characterization of Baylisascaris schroederi from Qinling subspecies of giant panda in China by the first internal transcribed spacer (ITS-1) of nuclear ribosomal DNA

In the present study, a total of 20 nematode isolates, (including 10 male and 10 female worms) representing Baylisascaris schroederi from 5 Qinling subspecies of giant pandas (Ailuropoda melanoleuca) in Shaanxi Province of China, were characterized and grouped genetically by the first internal transcribed spacer (ITS-1) of nuclear ribosomal DNA (rDNA). The rDNA fragment spanning 3' end of 18S rDNA, complete ITS-1 rDNA, and 5' end of 5.8S rDNA were amplified and sequenced. The sequence variability in ITS-1 rDNA was examined within B. schroederi and among parasites in order Ascaridata available in GenBank™, and their phylogenetic relationships were also reconstructed. The sequences of ITS-1 rDNA for all the B. schroederi isolates were 427 bp in length, with no genetic variation detected among these isolates. Phylogenetic analyses based on the ITS-1 rDNA sequences revealed that all the male and female B. schroederi isolates sequenced in the present study were posited into the clade of genus Baylisascaris, sistered to zoonotic nematodes in genus Ascaris, and the ITS-1 rDNA sequence could distinguish different species in order Ascaridata. These results showed that the ITS-1 rDNA provides a suitable molecular marker for the inter-species phylogenetic analysis and differential identification of nematodes in order Ascaridata.

Effect of DEM mesh size on AnnAGNPS simulation and slope correction

The objective of this paper is to study the impact of the mesh size of the digital elevation model (DEM) on terrain attributes within an Annualized AGricultural NonPoint Source pollution (AnnAGNPS) Model simulation at watershed scale and provide a correction of slope gradient for low resolution DEMs. The effect of different grid sizes of DEMs on terrain attributes was examined by comparing eight DEMs (30, 40, 50, 60, 70, 80, 90, and 100 m). The accuracy of the AnnAGNPS stimulation on runoff, sediments, and nutrient loads is evaluated. The results are as follows: (1) Rnoff does not vary much with decrease of DEM resolution whereas soil erosion and total nitrogen (TN) load change prominently. There is little effect on runoff simulation of AnnAGNPS modeling by the amended slope using an adjusted 50 m DEM. (2) A decrease of sediment yield and TN load is observed with an increase of DEM mesh size from 30 to 60 m; a slight decrease of sediment and TN load with the DEM mesh size bigger than 60 m. There is similar trend for total phosphorus (TP) variation, but with less range of variation, the simulation of sediment, TN, and TP increase, in which sediment increase up to 1.75 times compared to the model using unadjusted 50 m DEM. In all, the amended simulation still has a large difference relative to the results using 30 m DEM. AnnAGNPS is less reliable for sediment loading prediction in a small hilly watershed. (3) Resolution of DEM has significant impact on slope gradient. The average, minimum, maximum of slope from the various DEMs reduced obviously with the decrease of DEM precision. For the grade of 0∼15°, the slopes at lower resolution DEM are generally bigger than those at higher resolution DEM. But for the grade bigger than 15°, the slopes at lower resolution DEM are generally smaller than those at higher resolution DEM. So it is necessary to adjust the slope with a fitting equation. A cubic model is used for correction of slope gradient from lower resolution to that from higher resolution. Results for Dage watershed showed that fine meshes are desired to avoid large underestimates of sediment and total nitrogen loads and moderate underestimates of total phosphorus loads even with the slopes for the 50 m DEM adjusted to be more similar to the slopes from the 30 m DEM. Decreasing the mesh size beyond this threshold does not substantially affect the computed runoff flux but generated prediction errors for nitrogen and sediment yields. So the appropriate DEM will control error and make simulation at acceptable level.

Abstract P4-06-23: KLF8 Is Regulated by Its Novel Interacting Protein PARP-1

Krüppel-like factor 8 (KLF8) plays an important role in the progression of breast cancer invasion and metastasis. Using mass spectrometry and co-immunoprecipitation, we identified PARP-1, a chromatin-associated enzyme that catalyzes protein poly(ADP-ribosyl)ation (PARylation), as a novel KLF8 interacting protein. Co-IP and western blotting indicated that KLF8 is a PARylation substrate. Mutation of the cystein residues in the first and second zinc-finger motifs of KLF8 abolishes its interaction with PARP-1. Luciferase assays showed KLF8 activation on the cyclin D1 promoter was significantly reduced when PARP-1 was physically deleted or functionally inhibited or when KLF8-PARP-1 interaction was disrupted. Surprisingly, immunofluorescent staining demonstrated that KLF8 was localized in the nuclei of wide type MEFs, but was mislocalized in the perinuclear cytoplasm of the PARP-1-/- cells, which could be rescued by re-expression of PARP-1. The detection of γH2A.X, comet assay and clonogenic assay indicated KLF8 play a DNA repair role in a PARP-1- dependent matter. Cychloheximade-chase assay revealed the stability of KLF8 dramatically reduced by loss of PARP-1 or when KLF8-PARP-1 interaction was disrupted, meanwhile ubiquitination assay showed heavier ubiquitin chains of KLF8. This work has identified PARP-1 as a novel binding partner and post-translational modifier of KLF8 and a critical regulator of KLF8 localization, functions and stability in the cells and suggested a critical role of the interaction between KLF8 and PARP1 during metastatic progression of breast cancer. Support by: NIH, ACS and Komen grants to J.Z.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-06-23.

Over-expression of talin 1 and integrin-linked kinase in PBMCs of patients with ankylosing spondylitis: a proteomic study

OBJECTIVES

Ankylosing spondylitis (AS) is difficult to diagnose in its early stage due to the lack of simple and specific diagnostic indicators. This study was performed to screen candidate AS-associated proteins from peripheral blood mononuclear cells (PBMCs) of AS patients by combining a two-dimensional electrophoresis (2-DE) technique with mass spectrometry (MS) analysis.

METHODS

Twelve subjects consisting of 6 AS patients and 6 healthy volunteers (HVs) were enrolled in the 2-DE experiments. The protein expression patterns of PBMCs from different groups were analysed by PDQuest software, and the protein spots over/under-expressed by more than 2-fold between the two groups were identified by MS analysis. Western blot analyses were used to verify the differentially expressed proteins in 32 AS patients and 32 HVs.

RESULTS

Six proteins including pyruvate kinase (PK), profilin 1 (PFN1), talin 1 (TLN1), Chain A of cyclophilin A (CyPA), unknown protein (gi|16306948) and integrin-linked kinase (ILK) were identified from 10 over-expressed protein spots found by 2-DE in the AS group. Western blot experiments confirmed a higher expression of both TLN1 and ILK in AS group compared to the HV group (p<0.05).

CONCLUSIONS

TLN1 and ILK expressed higher in PBMCs of AS patients compared to healthy controls, which were involved in the integrin signalling pathway. The two proteins are likely novel disease-associated proteins and potential disease markers of AS.

Human adipose tissue-derived adult stem cells can lead to multiorgan engraftment

Recent studies have demonstrated the existence of a population of adipose tissue-derived adult stem cells that can undergo multilineage differentiation in vitro; however, it is unclear whether these cells maintain their multilineage differentiation in vivo. The objective of the present study was to examine the in vivo characteristics and behavior of a potential population of human adipose tissue-derived adult stem cells. Herein, we demonstrate that human adipose tissue-derived adult stem cells differentiate into the epithelium of the gastrointestinal tract, liver, and bronchi, and an endothelial lineage after transplantation into irradiated nonobese mice with diabetes or severe combined immunodeficiency. These findings may contribute to clinical tissue repair after injury.

Spin polarization induced by in-plane electric and magnetic fields in two-dimensional heavy-hole systems

Using a nonequilibrium Green function approach, we systematically investigate the current induced spin polarization (CISP) in a two-dimensional heavy-hole system with cubic Rashba spin-orbit coupling, driven by in-plane electric and magnetic fields. We find that when a magnetic field is applied along the direction of electric field, the longitudinal conductivity drops monotonously with an increase of magnetic-field strength or of hole density. The spin polarization along the electric-field direction is just the Pauli paramagnetism and it quadratically increases with an increase of hole density. The nonvanishing out-of-plane component of spin polarization emerges for both short-range and long-range disorders, and it changes sign with the variation of magnetic field, especially for long-range hole-impurity scattering. In the magnetic-field dependences of this out-of-plane CISP and of the in-plane CISP perpendicular to the electric field, there are singular magnetic fields, below or above which the effects of magnetic field are completely different.

A numerical investigation of the effect of vertex geometry on localized surface plasmon resonance of nanostructures

Advances in nanofabrication and nano-scale measurement methods now allow for fabrication of highly detailed nanometer-scale topographic features. As geometric features greatly impact the formation of an electromagnetic field in response to incident light, this in turn calls for the study of the effects of new features of nanostructures on their performance in applications such as localized surface plasmon resonance (LSPR) sensing. This paper studies the effects of vertex features of a single nanostructure on its LSPR properties. A general relationship between the LSPR spectra and the vertex features of a nanoparticle is established. The results of electrodynamics calculations show that a delta-star with a relatively small vertex angle exhibits a bigger resonant wavelength than one with a large vertex angle. Moreover, the sensing performance initially increases, and then decreases as angular size of the vertices increases, with a turning point of 30 degrees. It is also shown that for nanostars with different numbers of vertices, the resonant wavelength undergoes a blue shift and the sensing performance grows poorer as the number of vertices increases. A regular vertex angle of 30 degrees displays the greatest figure of merit (FOM) value for LSPR applications, approximately 9.5 RIU(-1).

Effects of vertex truncation of polyhedral nanostructures on localized surface plasmon resonance

Polyhedral nanostructures are widely used to enable localized surface plasmon resonance (LSPR). In practice, vertices of such structures are almost always truncated due to limitations of nanofabrication processes. This paper studies the effects of vertex truncation of polyhedral nanostructures on the characteristics of LSPR sensing. The optical properties and sensing performance of triangular nanoplates with truncated vertices are investigated using electrodynamics analysis and verified by experiment. The experimental results correlated with simulation analysis demonstrate that the fabricated triangular nanoplate array has a truncation ratio, defined as the length of truncation along an edge of the triangle over the edge length, of approximately 12.8%. This significantly influences optical properties of the nanostructures, resulting in poorer sensing performance. These insights can be used to guide the design and fabrication of nanostructures for high performance LSPR sensors.

Comparison of radiography, CT and MR imaging in detection of arthropathies in patients with haemophilia

To compare magnetic resonance (MR) imaging, computed tomography (CT) and radiography for the detection of arthropathies in patients with haemophilia. Forty-one symptomatic joints in 14 men with haemophilia, ages 11-24 years (mean age 17.5 +/- 3.9 years) were examined with radiography, CT and MR. Images of each joint were acquired on the same day. The precontrast MR examination obtained coronal spin-echo T1 images and gradient echo with rephasing T2* images, as well as sagittal, axial gradient echo with rephasing T2* images using a low-field-strength 0.3-T MR imager. For the postcontrast MR examination, coronal, sagittal and axial images were acquired using the same precontrast T1 sequence. Thirteen joints were also examined on enhanced MR. The severity of damage was classified using conventional radiographical staging. Severely affected haemophilic arthropathy (HA) patients (stage 5) were excluded. Findings of soft tissue swelling, osteoporosis, epiphyseal overgrowth, joint erosion, cysts, joint space narrowing, bone marrow oedema, joint effusion, haemorrhage, synovial hypertrophy and widened intercondylar notches as well as anterior and posterior cruciate ligaments (for the knee) were used in all imaging comparisons. The joints were classified by radiographical criteria into stage 0 (n = 5), stage 1 (n = 7), stage 2 (n = 6), stage 3 (n = 8) and stage 4 (n = 15). Soft tissue swelling or joint effusion was observed in 33 joints on radiographs, in 34 on both CT and MR; joint erosions were observed in 34 joints on MR, 33 on CT and 20 on radiographs. Joint cysts appeared in 21 joints on MR, 18 on CT and 9 on radiographs. Significant differences in detection of erosion and cysts were found between radiography and CT (P < 0.05) and radiography and MR imaging (P < 0.05), not between CT and MR (P > 0.05). MR was better for detecting foci of both erosion and cysts than CT and radiography, and CT was better than radiography. MR imaging, CT and radiography were equally effective in showing the changes of epiphyseal overgrowth in 26 joints, joint space narrowing in 14 joints and widened intercondylar notches in 20 knee joints. However, only MR imaging detected tears in 17 anterior and 13 posterior cruciate ligaments in the 20 knee joints with widened intercondylar notches. Bone marrow oedema in 14 joints, haemorrhage in 34 joints and synovial hypertrophy in 27 joints were seen on MR images, but not on CT or radiography. MR imaging is superior to CT and conventional radiography for detecting abnormal changes and should be considered the first choice among imaging modalities in evaluating HAs.

Association of chromosome 2q36.1-36.3 and autosomal dominant transmission in ankylosing spondylitis: results of genetic studies across generations of Han Chinese families

Background:

Ankylosing spondylitis (AS) is a chronic, potentially crippling, spondyloarthropathy with strong genetic components affecting approximately 0.3% of the population. Its exact genetic mechanism and mode of transmission, however, remains obscure.

Methods and results:

The authors conducted a genome wide scan on 75 individuals across multiple generations of three Han Chinese families affected with AS. Segregation analysis and pedigree investigation suggested an autosomal dominant inheritance. Pairwise logarithm of odds (LOD) scores were calculated using LINKAGE package for the obtained genotypes. High resolution mapping was then performed based on markers with significant LOD scores. To minimise the number of crossovers in each family, haplotype were constructed and assigned. Two of the pedigrees shared one candidate region for AS on 2q36.1–2q36.3 spanning 6-cM (maximum heterogeneity LOD score of 12.41 at marker D2S2228), while the other showed strong linkage to the HLA-B region.

Conclusions:

This is the first report which proposes one of the new genetic models of autosomal dominant transmission in AS. The breakthrough in the identification of linkage to chromosome 2q36.1–2q36.3 and the HLA-B region highlights the future potential of more comprehensive genetic studies of determinants of disease risk.

Promethium-147 capacitor

Beta particle surface fluxes for tritium, Ni-63, Pm-147, and Sr-90 sources were calculated in this work. High current density was experimentally achieved from Pm-147 oxide in silica-titana glass. A 96 GBq (2.6 Ci) Pm-147 4pi-source with flux efficiency greater than 50% was used for constructing a direct charge capacitor with a polyimide coated collector and vacuum as electrical insulation. The capacitor connected to high resistance (TOmega) loads produced up to 35 kV. Overall conversion efficiency was over 10% (on optimal load).

Preclinical characterization of WAY-211612: a dual 5-HT uptake inhibitor and 5-HT (1A) receptor antagonist and potential novel antidepressant

BACKGROUND AND PURPOSE

As a combination of 5-HT selective reuptake inhibitor (SSRI) with 5-HT(1A) receptor antagonism may yield a rapidly acting antidepressant, WAY-211612, a compound with both SSRI and 5-HT(1A) receptor antagonist activities, was evaluated in preclinical models.

EXPERIMENTAL APPROACH

Occupancy studies confirmed the mechanism of action of WAY-211612, while its in vivo profile was characterized in microdialysis and behavioural models.

KEY RESULTS

WAY-211612 inhibited 5-HT reuptake (K(i) = 1.5 nmol.L(-1); K(B) = 17.7 nmol.L(-1)) and exhibited full 5-HT(1A) receptor antagonist activity (K(i) = 1.2 nmol.L(-1); K(B) = 6.3 nmol.L(-1); I(max) 100% in adenyl cyclase assays; K(B) = 19.8 nmol.L(-1); I(max) 100% in GTPgammaS). WAY-211612 (3 and 30 mg.kg(-1), po) occupied 5-HT reuptake sites in rat prefrontal cortex (56.6% and 73.6% respectively) and hippocampus (52.2% and 78.5%), and 5-HT(1A) receptors in the prefrontal cortex (6.7% and 44.7%), hippocampus (8.3% and 48.6%) and dorsal raphe (15% and 83%). Acute or chronic treatment with WAY-211612 (3-30 mg.kg(-1), po) raised levels of cortical 5-HT approximately twofold, as also observed with a combination of an SSRI (fluoxetine; 30 mg.kg(-1), s.c.) and a 5-HT(1A) antagonist (WAY-100635; 0.3 mg.kg(-1), s.c). WAY-211612 (3.3-30 mg.kg(-1), s.c.) decreased aggressive behaviour in the resident-intruder model, while increasing the number of punished crossings (3-30 mg.kg(-1), i.p. and 10-56 mg.kg(-1), po) in the mouse four-plate model and decreased adjunctive drinking behaviour (56 mg.kg(-1), i.p.) in the rat scheduled-induced polydipsia model.

CONCLUSIONS AND IMPLICATIONS

These findings suggest that WAY-211612 may represent a novel antidepressant.

Adiabatic self-tuning in a silicon microdisk optical resonator

We demonstrate a method for adiabatically self-tuning a silicon microdisk resonator. This mechanism is not only able to sensitively probe the fast nonlinear cavity dynamics, but also provides various optical functionalities like pulse compression, shaping, and tunable time delay.

A proposal for highly tunable optical parametric oscillation in silicon micro-resonators

We propose a novel scheme for continuous-wave pumped optical parametric oscillation (OPO) inside silicon micro-resonators. The proposed scheme not only requires a relative low lasing threshold, but also exhibits extremely broad tunability extending from the telecom band to mid infrared.

Nonlinear optical phenomena in silicon waveguides: modeling and applications

<p> <a href="http://oe.osa.org/virtual_issue.cfm?vid=36">Focus Serial: Frontiers of Nonlinear Optics</a> </p>Several kinds of nonlinear optical effects have been observed in recent years using silicon waveguides, and their device applications are attracting considerable attention. In this review, we provide a unified theoretical platform that not only can be used for understanding the underlying physics but should also provide guidance toward new and useful applications. We begin with a description of the third-order nonlinearity of silicon and consider the tensorial nature of both the electronic and Raman contributions. The generation of free carriers through two-photon absorption and their impact on various nonlinear phenomena is included fully within the theory presented here. We derive a general propagation equation in the frequency domain and show how it leads to a generalized nonlinear Schrodinger equation when it is converted to the time domain. We use this equation to study propagation of ultrashort optical pulses in the presence of self-phase modulation and show the possibility of soliton formation and supercontinuum generation. The nonlinear phenomena of cross-phase modulation and stimulated Raman scattering are discussed next with emphasis on the impact of free carriers on Raman amplification and lasing. We also consider the four-wave mixing process for both continuous-wave and pulsed pumping and discuss the conditions under which parametric amplification and wavelength conversion can be realized with net gain in the telecommunication band.

Decreased expression level of SH2 domain-containing protein tyrosine phosphatase-1 (Shp1) is associated with progression of chronic myeloid leukaemia

Chronic myeloid leukaemia (CML) is characterized by t(9;22)(q34;q11) and the aberrant expression of the fusion protein Bcr-Abl that leads to constitutive activation of c-Abl kinase. Bcr-Abl plays a major role in the development and progression of CML through chronic, accelerated, and blast phases. The interaction between Bcr-Abl and other oncogenic molecules has been extensively documented. Nonetheless, negative regulatory mechanisms of Bcr-Abl are not completely defined. One major inhibitory pathway is mediated via the SH2 domain-containing protein tyrosine phosphatase Shp1. In the present study, we demonstrate that Shp1 levels are markedly decreased in advanced stage CML patients compared with those in chronic phase. This process was independent of DNA methylation. Furthermore, we did not detect mutations in the Shp1 gene in CML cell lines or patient samples. These data suggest that the decrease in Shp1 in advanced stage CML patients is due to post-transcriptional modifications. Our findings suggest that the decrease in Shp1 expression levels plays a role in the progression of CML. Also, the decrease in Shp1 and subsequently its inhibitory effect on Bcr-Abl could provide an explanation for imatinib resistance seen in advanced stage CML patients.

Using human adipose tissue-derived mesenchymal stem cells as salvage therapy for hepatic graft-versus-host disease resembling acute hepatitis

A 43-year-old woman with chronic hepatic graft-versus-host disease (GVHD) who failed previous immunosuppressive therapy with cyclosporine and prednisone was treated with tacrolimus starting on day 165 after allogeneic hematopoietic stem cell transplantation. Fifteen days later, tacrolimus was discontinued because of progressive deterioration of renal function. However, after changing treatment to human adipose tissue-derived mesenchymal stem cells (AMSC), we observed rapid and complete resolution of hepatic GVHD and renal toxicity. We concluded that it is worthwhile to administer AMSC as a treatment for common hepatic GVHD, particularly for atypical cases presenting as acute hepatitis.

Biodegradation of nicotine from tobacco waste extract by Ochrobactrum intermedium DN2

Ochrobactrum intermedium DN2 was used to degrade nicotine in tobacco waste extracts. The optimal temperature and pH of nicotine degradation by strain DN2 was 30-37 degrees C and 7.0, respectively. Under these optimal conditions, the average degradation rate of nicotine in a 30L fed-batch culture was 140.5 mg 1(-1) h(-1). The results of this study indicate that strain DN2 may be useful for reducing the nicotine content of reconstituted tobacco.

Evaluation of quality of life using ASQoL questionnaire in patients with ankylosing spondylitis in a Chinese population

The purpose of this study was to evaluate the reliability of Chinese version of the ankylosing spondylitis quality of life questionnaire (ASQoL) for AS patients. All the enrolled AS patients should fulfill five questionnaires (BASDAI, BASFI, DFI, BAS-G and ASQoL) by himself, then the investigators did physical examination of the patients, fulfilling BASMI. Physical function has a strong correlation with QoL in patients with AS. In different disease activity groups, ASQoL had a correlation with BASFI, especially in the moderate activity group (gamma = 0.66, P < 0.0001). All four questionnaires in entanacept treatment group improved distinctly on week 6 and 12 comparing to baseline. There were significantly correlations of changing between ASQoL and BAS-G, BASDAI and BASFI after treatment with etanercept in AS patients. The Chinese ASQoL questionnaire is valuable to evaluate the activity of AS patients and effect of biologic agent treatment in patients with AS. It is a good generic instrument to measure QoL in patients with AS in China.

Silicon waveguides for creating quantum-correlated photon pairs

We propose to use four-wave mixing inside silicon waveguides for generating quantum-correlated photon pairs in a single spatial mode. Such silicon-based photon sources not only exhibit high pair correlation but also have high spectral brightness. As the proposed scheme is based on mature silicon technology, it has the potential of becoming a cost-effective platform for on-chip quantum information processing applications.

Raman response function for silica fibers

The commonly used Lorentzian form of the Raman response function for studying propagation of ultrashort pulses in silica fibers does not properly account for the shoulder in the Raman gain spectrum originating from the Boson peak. We propose a more accurate form of this response function and show that its predictions for the Raman-induced frequency shift should be in better agreement with experiments.

Restoration of shp1 expression by 5-AZA-2'-deoxycytidine is associated with downregulation of JAK3/STAT3 signaling in ALK-positive anaplastic large cell lymphoma

Anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALK+ ALCL) is characterized by constitutive activation of the Janus kinase (JAK)3/signal transducers and activators of transcription 3 (STAT3) signaling pathway. SHP1, a tyrosine phosphatase that negatively regulates JAK/STAT, is frequently absent in ALK+ ALCL owing to gene methylation. To test the hypothesis that loss of SHP1 contributes to JAK3/STAT3 activation in ALK+ ALCL cells, we induced SHP1 expression using 5-aza-2'-deoxycytidine (5-AZA), an inhibitor of DNA methyltransferase, in ALK+ ALCL cell lines, and correlated with changes in the JAK3/STAT3 pathway. 5-AZA gradually restored SHP1 expression in Karpas 299 and SU-DHL-1 cells over 5 days. The initially low level of SHP1 expression did not result in significant changes to the expression or tyrosine phosphorylation of JAK3 and STAT3. However, higher levels of SHP1 seen subsequently correlated with substantial decreases in JAK3 and pJAK3, followed by pSTAT3 (but not STAT3). Importantly, the decrease in JAK3 was abrogated by MG132, a proteasome inhibitor. 5-AZA induced no significant increase in apoptosis but it sensitized ALCL cells to doxorubicin-induced apoptosis. Our findings support the concept that loss of SHP1 contributes to the constitutive activation of JAK3/STAT3 in ALK+ ALCL cells. SHP1 appears to downregulate JAK3 by two mechanisms: tyrosine dephosphorylation and increased degradation via the proteasome pathway.

High-order harmonic generation in a tightly focused laser beam

The force due to the transverse magnetic field of a laser beam drives an electron in the direction of laser propagation, thereby impeding the recollision mechanism for high-order harmonic generation. The longitudinal electric field component of a tightly focused Gaussian beam can sufficiently counteract the magnetic force to enhance the harmonic yield substantially. For tight focusing and a laser intensity of 10(18) W/cm2, it can raise the harmonic yield by several orders of magnitude.

Enhanced dissipation of phenanthrene and pyrene in spiked soils by combined plants cultivation

Polycyclic aromatic hydrocarbons (PAHs), a class of POPs, are widely distributed in the environment. Phytoremediation has long been recognized as a cost-effective method for removal of PAHs pollutants from soil. This study was conducted to investigate the capability of three plant species separately and their combination to promote the degradation of phenanthrene and pyrene in soil. The performance of three plant species, maize, ryegrass and white clover for phenanthrene and pyrene removal was also compared. The result showed that the presence of vegetation significantly enhances the dissipation of phenanthrene and pyrene in the soil environment. This effect was especially marked with maize. At the end of 60 days treatment, phenanthrene and pyrene concentrations in treated soils declined from an initial 52.52 mg kg-1 and 58.19 mg kg-1 to 4.15 mg kg-1 and 6.77 mg kg-1, respectively, indicating that phenanthrene and pyrene was successfully removed by maize. Around 92.10% of phenanthrene and 88.36% of pyrene were removed from soils planted with maize. Within approximately two months experimental period, the dissipation extent showed that the 4-ring pyrene was more recalcitrant than 3-ring phenanthrene. Although the extents did not differ significantly among three tested species, the rates of degradation were different. The maize treatment had the highest rate of contaminant removal after two months, followed by white clover and annual ryegrass. As compare to single plant cultivation, combined plants cultivation significantly enhanced the destruction rate and extent of phenanthrene and pyrene in soils. Around 98.22% of phenanthrene and 95.81% of pyrene were removed from soils planted with maize and ryegrass. This research indicates the potential for phenanthrene and pyrene mineralization in combined plants cultivation, which may be especially useful for phytoremediation of soils contaminated with PAHs.

Dispersion tailoring and soliton propagation in silicon waveguides

The dispersive properties of silicon-on-insulator (SOI) waveguides are studied by using the effective-index method. Extensive calculations indicate that an SOI waveguide can be designed to have its zero-dispersion wavelength near 1.5 microm with reasonable device dimensions. Numerical simulations show that soliton-like pulse propagation is achievable in such a waveguide in the spectral region at approximately 1.55 microm. The concept of path-averaged solitons is used to minimize the impact of linear loss and two-photon absorption.

Photon-pair generation by four-wave mixing in optical fibers

We present a theory to quantify a fundamental limit on correlated photon pairs generated through four-wave mixing inside optical fibers in the presence of spontaneous Raman scattering (SpRS). Our theory is able to explain current experimental data. We show that if correlated photon pairs are generated with polarization orthogonal to the pump the effect of SpRS is significantly reduced over a broad spectral region extending from 5 to 15 THz.

Microscale localized spectroscopy with a magnetic resonance force microscope

Magnetic resonance force microscopy is combined with spin-echo spectroscopy to obtain spatially and spectrally resolved NMR signals of micrometer-scale objects. The experimental spatial resolution for the demonstration experiment on a sample consisting of Ba(ClO3)2.H2O and (NH4)2SO4 single crystals is 3.4 microm. The spectral resolution of 3.4 kHz is sample limited. Improvements in resolution and extensions of the method to more than one spatial dimension and to multidimensional spectroscopy are possible.

Pump-noise transfer in dual-pump fiber-optic parametric amplifiers: walk-off effects

Transfer of intensity noise from pumps to signal in dual-pump fiber-optic parametric amplifiers is simulated numerically for a realistic configuration in which both pumps are amplified and filtered before they enter the fiber. The walk-off effects induced by different group velocities of pumps, signal, and idler are fully taken into account. It is found that the optical signal-to-noise ratio can be as low as 15 dB when the amplifier length is close to 0.5 km, but it can be improved by 3 dB or so by use of longer fibers.

Intrapulse depolarization in optical fibers: a classical analog of spin decoherence

We show that the combination of cross-phase modulation and polarization-mode dispersion inside optical fibers leads to a novel phenomenon of intrapulse depolarization manifested as different random states of polarization across the pulse profile. Such polarization evolution of optical pulses is directly analogous to the phenomenon of spin decoherence in semiconductors or pseudospin relaxation in atoms.

Expression of survivin and bax/bcl-2 in peroxisome proliferator activated receptor-gamma ligands induces apoptosis on human myeloid leukemia cells in vitro

The present study was undertaken to investigate the mechanisms of peroxisome proliferator activated receptor-gamma (PPAR-gamma) ligand-induced apoptosis on human myeloid leukemia K562 and HL-60 cell lines. The results revealed that both 15-deoxy-delta(12,14)-prostaglandin J2 (15d-PGJ2) and troglitazone (TGZ) have significant anti-proliferation- and apoptosis-inducing effects on these two kinds of leukemia cells. Marked morphological changes of cell apoptosis including condensation of chromatin and nuclear fragmentation were observed clearly using Wright's and Hoechst 33258 staining. Reverse transcription-PCR and western blot analyses demonstrated that both survivin and bcl-2 expression were downregulated markedly, while bax expression was upregulated concurrently when apoptosis occurred. We therefore conclude that 15d-PGJ2 and TGZ have significant apoptosis effects on K562 and HL-60 cells in vitro, and that upregulation of bax as well as downregulation of survivin and bcl-2 expression may be the important apoptosis-inducing mechanisms. The results suggest that PPAR-gamma ligands may serve as potential therapeutic agents for both acute and chronic myeloid leukemia.