Optical rogue waves generated on Gaussian background beam

We study optical rogue waves (RWs) in a nonlinear graded-index waveguide with variable coefficients. An exact RW solution on Gaussian background beam is presented, in contrast to the previous studies about RWs, on plane wave background. It is shown that the characteristics of RWs are maintained on Gaussian background beam and that the beam's width is even a bit smaller than the RWs scale. These results may raise the possibility of related experiments and potential applications in nonlinear optics.

Off-diagonal Bethe ansatz and exact solution of a topological spin ring

A general method is proposed for constructing the Bethe ansatz equations of integrable models without U(1) symmetry. As an example, the exact spectrum of the XXZ spin ring with a Möbius-like topological boundary condition is derived by constructing a modified T-Q relation based on the functional connection between the eigenvalues of the transfer matrix and the quantum determinant of the monodromy matrix. With the exact solution, the elementary excitations of the topological XX spin ring are discussed in detail. It is found that the excitation spectrum indeed shows a nontrivial topological nature.

Axonal loss and blood flow disturbances in the natural course of indirect traumatic optic neuropathy

BACKGROUND

Indirect traumatic optic neuropathy (TON) is an acute injury of the optic nerve associated with severe visual dysfunction, which may be a result of secondary mechanical injury and vascular disorder of the optic nerve due to trauma. We analyzed the natural course of axonal loss and blood flow disturbances in patients with indirect TON to find a possible therapeutic window.

METHODS

A cohort of 54 patients with indirect TON recruited between October 2008 and October 2010 at Beijing Tongren Hospital was retrospectively analyzed. The patients were divided into no light perception group (NLP) and better than NLP (btNLP) group. Specifically, the thickness of the retinal nerve fiber layer (RNFL) measured by spectral domain optical coherence tomography (SD-OCT), and hemodynamic parameters of the ophthalmic artery (OA), central retinal artery (CRA) and posterior ciliary artery (PCA) were determined.

RESULTS

Two weeks after injury, there was a statistically significant decrease in the thickness of RNFL in the btNLP group as compared with the fellow control eyes (P < 0.05). In contrast, in the NLP group, RNFL thickness slightly increased for 2 weeks following injury, then overtly reduced after 4 weeks (P < 0.05). Peak systolic velocity (PSV) of CRA was significantly decreased 4 weeks after injury (P < 0.05) in both the NLP group and btNLP group (P < 0.05). The thickness of RNFL in the NLP group was negatively correlated with PSV of CRA after 1 week of injury (P < 0.05, r = -0.962).

CONCLUSIONS

SD-OCT is a useful supplement in detecting the axonal loss in TON. The dynamic change of the thickness of RNFL appears to correlate with the hemodynamic disturbances in the natural course of TON. The first 2 weeks following an injury is critical and should be considered as the therapeutic window for TON patients.

X-Ray spectra and electronic correlations of FeSe(1-x)Te(x)

Critical issues concerning emerging Fe-based superconductors include the degree of electron correlation and the origin of the superconductivity. X-Ray absorption spectra (XAS) and resonant inelastic X-ray scattering spectra (RIXS) of FeSe(1-x)Te(x) (x = 0-1) single crystals were obtained to study their electronic properties that relate to electron correlation and superconductivity. The linewidth of Fe L(2,3)-edges XAS of FeSe(1-x)Te(x) is narrower than that of Fe-pnictides, revealing the difference between their hybridization effects and localization character and those of other Fe-pnictides. While no significant differences exist between the Fe L-edge XAS and RIXS of FeSe(1-x)Te(x) and those of Fe-pnictides, Se K-edge and Te K-edge XAS exhibit substantial edge shift, suggesting that the superconductivity in an Fe-Se superconductor is strongly associated with the ligand states. A comparison of the Se K-edge and Te K-edge spectra reveals that the charge transfer may occur between Se and Te. Given the Coulomb interaction and the bandwidth, the spectral results indicate that FeSe(1-x)Te(x) is unlikely to be a weakly correlated system unlike the Fe-pnictides of the "1111" and "122" families. The spectral results further demonstrate that superconductivity in this class of Fe-based compounds is strongly associated with the ligand 4p hole state.

Ferromagnetic enhancement of CE-type spin ordering in (Pr,Ca)MnO3

We present resonant soft x-ray scattering results from small bandwidth manganites (Pr,Ca)MnO(3), which show that the CE-type spin ordering (SO) at the phase boundary is stabilized only below the canted antiferromagnetic transition temperature and enhanced by ferromagnetism in the macroscopically insulating state (FM-I). Our results reveal the fragility of the CE-type ordering that underpins the colossal magnetoresistance effect in this system, as well as an unexpected cooperative interplay between FM-I and CE-type SO which is in contrast to the competitive interplay between the ferromagnetic metallic state and CE-type ordering.

[Finite element contact stress analysis of simulating teeth with wedge shaped defects in the cervical region]

OBJECTIVE

To study the distribution of stress of simulating teeth with wedge shaped defects in the cervical region.

METHODS

The models of anisotropic enamel of the mandibular first premolar and the opposite maxillary first premolar crown were created. A defect was introduced into the model of mandibular premolar in the buccal cervical region along the enamelo-dentinal junction (DEJ). The stress distribution in the cervical region of the mandibular premolar was investigated considering lateral condition simulating working micromotions. In this case, the stroke was applied to the maxillary first mandibular in a stepping procedure using nonlinear contact analysis.

RESULTS

The stresses were concentrated in the defect of the enamel and dentin at the DEJ in the condition of lateral loading. As the defect length increased in size, the peak maximum principal stress (MPS) value and the magnitude of the stress field along the DEJ both increased.

CONCLUSION

Undermined cervical DEJ had a significant effect on the stress distribution in the buccal cervical region.

[Traditional medicine CDP and promoter demethylation in breast cancer cell lines]

OBJECTIVE

To investigate the demethylation effect of CDP on P16 and E-CADHERIN genes.

METHODS

Breast cancer cell lines T47D and MDA-MB-435 were treated with CDP and DNA methyltransferase inhibitor 5-azacytidine (5-aza-C). The methylation of P16 and E-CADHERIN gene promoters were measured by methylation-specific PCR (MSP). The RNA transcription was determined by reverse transcription-PCR(RT-PCR).

RESULTS

1) The methylation-specific fragments of P16 gene promoter existed in T47D cells after 25, 50 and 75 micromol/L of CDP treatment for 6 days. An absolute demethylation on P16 gene occurred after treatment with 100 micromol/L of CDP. The unmethylation-specific fragments appeared in T47D cells after being treated with 25, 50, 75 and 100 micromol/L of CDP for 6 days. The RNA expression of P16 was detected after treatment with 75 and 100 micromol/L of CDP. 2) After being treated with 50 micromol/L of CDP, the methylation-specific fragments of CpG island in P16 gene promoter still existed in T47D cells. The unmethylation-specific fragments in T47D cells started to appear after 24 hours of treatment and lasted until 144 hour of treatment. The RNA expression was detected after 144 hours of treatment. 3) The demethylation on E-CADHERIN gene and genomic DNA or RNA transcription were not detected in MDA-MB-435 cells.

CONCLUSION

CDP has concentration- and time-dependent demethylation effect on P16 gene in T47D cells, but not on E-CADHERIN gene in MDA-MB-435 cells, which indicates that CDP has substantial diversity in molecular activities.

[Cloning, expression, purification and identification of multi-potent transcription factor CTCF recombinant and its segments]

OBJECTIVE

To clone ctc f cDNA, N, Zn and C fragments separately into expresstion vector, purify and identify the expressed proteins.

METHODS

Using the recombinant plasmid pGEM7Zf (-)-ctc f as template for PCR, pGEX-4T-2-ctc f, pGEX-4T-2-ctc f-N, pGEX-4T-2- ctc f-Zn and pGEX-4T-2- ctc f-C recombinants were constructed successfully. After transformed into E. coli BL21 cells, the recombinants were confirmed by enzyme digestion and sequence analysis. After optimizing the IPTG inducing condition, the purified GST fusion proteins with affinity chromatography were conformed by Far-Western blotting.

RESULTS

The recombinant plasmids pGEX-4T-2-ctc f, pGEX-4T-2- ctc f-N, pGEX-4T-2-ctc f-Zn and pGEX-4T-2-ctc f-C were confirmed by restriction enzyme assay and sequencing. All GST fusion proteins, CTCF, CTCF-N, CTCF-Zn and CTCF-C were successfully expressed at the optimal parameters and purified with affinity chromatography, and specifically recognized by anti-GST antibody.

CONCLUSION

Ctc f, ctc f-n, ctc f-Zn and ctc f-c gene recombinants were constructed successfully and their corresponding fusion proteins were successfully purified with affinity chromatography and identified.

The effects of maternal Cd on the metallothionein expression in tilapia (Oreochromis mossambicus) embryos and larvae

The purpose of this study was to identify the factor(s) which would enhance the Cd resistance as assessed by the metallothionein (MT) expression in tilapia larvae. Larvae were collected from parents that were pretreated respectively with Cd or saline. At the end of the 12-week experiment, the hepatic MT and Cd contents in the breeding female fish were recorded. Our results indicated that a significant relationship between Cd and MT contents can be found in the offspring from the parent fish treated with Cd. However, the higher Cd resistance, Cd contents, and MT expression were limited to those larvae from parent fish bred within 4 weeks of the injection. By week 12, the Cd-treated fish still contained high levels of MT in their hepatic tissues. However, the MT and Cd contents in the larvae from these adult fish were not significantly different from those from the controls. In summary, we suggest that the higher Cd resistance of larvae from the egg stage was a result of the Cd contamination of the parent female, as evidenced by an increase in MT expression induced in tilapia embryos and larvae.

Monochromatic Electron Photoemission from Diamondoid Monolayers

We found monochromatic electron photoemission from large-area self-assembled monolayers of a functionalized diamondoid, [121]tetramantane-6-thiol. Photoelectron spectra of the diamondoid monolayers exhibited a peak at the low-kinetic energy threshold; up to 68% of all emitted electrons were emitted within this single energy peak. The intensity of the emission peak is indicative of diamondoids being negative electron affinity materials. With an energy distribution width of less than 0.5 electron volts, this source of monochromatic electrons may find application in technologies such as electron microscopy, electron beam lithography, and field-emission flat-panel displays.

Enhancement of Intracellular Delivery of CdTe Quantum Dots (QDs) to Living Cells by Tat Conjugation

Quantum dots (QDs), as novel fluorescence probes, have shown a great potential for bio-molecular labeling and cellular imaging. To stain cellular targets, the sufficient intracellular delivery of QDs is required. In this work the tat, a typical membrane-permeable carrier peptide, was conjugated with thiol-capped CdTe QDs to form CdTe Tat-QDs, and the intracellular deliveries of CdTe QDs or CdTe Tat-QDs were compared in human hepatocellular carcinoma (QGY) cells and human breast cancer (MCF7) cells in vitro by means of confocal laser scanning microscopy. Added into the cell dishes, both QDs and Tat-QDs adhered to the outer leaflet of the plasma membrane of cells within a few minutes, but the binding amount of Tat-QDs was obviously higher than that of QDs. Then both QDs and Tat-QDs can penetrate into cells, and their cellular contents increased with incubation time but both saturated after 3 hours incubation. However the cellular levels of Tat-QDs were higher than those of QDs, with the ratio of 2.1 (+/-0.3) times in QGY cells and 1.5 (+/-0.2) times in MCF7 cells, demonstrating the enhancing effect of Tat conjugation on the intracellular delivery of QDs.

Energy dispersion of 4f-derived emissions in photoelectron spectra of the heavy-fermion compound YbIr2Si2

Angle-resolved photoemission spectra of the heavy-fermion system YbIr(2)Si(2) are reported that reveal strong momentum (k) dependent splittings of the 4f(13) bulk and surface emissions around the expected intersection points of the 4f final states with valence bands in the Brillouin zone. The obtained dispersion is explained in terms of a simplified periodic Anderson model by a k dependence of the electron hopping matrix element disregarding clearly interpretation in terms of a single-impurity model.

[Correlation of antitumor effect of recombinant sea snake basic phospholipase A2 to its enzymatic activity]

BACKGROUND & OBJECTIVE

Snake venom phospolipase A2 (PLA(2)), a large family of homologous (14 ku) soluble proteins, exerts diverse pharmacologic activities as well as enzymatic activities. So far, the structure and function of terrestrial snake PLA(2), especially the relationship of its enzymatic and pharmacologic activities have been studied extensively, but the investigation of sea snake PLA(2) are limited. This study was to investigate the in vitro and in vivo antitumor effects of recombinant sea snake basic PLA(2) (rSSBPLA(2)) and its mutants rN48 and rK4 from sea snake Lapemis hardwickii venom, and to explore the influence of 2 residues related with the enzymatic activity on the antitumor effects.

METHODS

Site-directed mutagenesis of the 2 conserved residues related with enzymatic activity (His48 mutated to Asn and Asp49 mutated to Lys) was performed. The inhibitory effects of rSSBPLA(2), rN48 and rK49 on proliferation of human myeloid leukemia cell line HL-60, human neuroblastoma cell line SK-N-SH, human gastric cancer cell line MGC-803, and human liver cancer cell line HepG2 were assessed by MTT assay. Their antitumor effects on sarcoma cell line S180 xenograft and EAC ascites cancer model in mice were detected.

RESULTS

The relative enzymatic activities of rN48 and rK49 were 0 and 5% of that of rSSBPLA(2). The 50% inhibitory concentration (IC(50)) of rSSBPLA(2) for HL60, SK-N-SH, and MGC-803 cells were (45.28+/-0.09) microg/ml, (57.07+/-0.12) microg/ml, and (69.34+/-0.35) microg/ml, respectively, but it had no inhibitory effect on proliferation of HepG2 cells. rSSBPLA(2) obviously inhibited growth of S180 xenograft in miceû the inhibitory rates were 50.8%, 43.2%, 38.2%, and 55.5%, respectively, under the dose of 2 mg/kg (qd x 10), 2 mg/kg (q2d x 5), 4 mg/kg (qd x 1) and 4 mg/kg (q5d x 2). The inhibitory rate of EAC model was 33.5% under the dose of 4 mg/kg (q5d x 2). The inhibitory rates were significantly higher in test groups than in control groups (P<0.01). rN48 and rK49 had no inhibitory effect on proliferation of the 4 tumor cell lines and on growth of the xenograft tumors.

CONCLUSION

The antitumor effect of rSSBPLA(2) may be closely related with its enzymatic activity.

Nodal quasiparticle in pseudogapped colossal magnetoresistive manganites

A characteristic feature of the copper oxide high-temperature superconductors is the dichotomy between the electronic excitations along the nodal (diagonal) and antinodal (parallel to the Cu-O bonds) directions in momentum space, generally assumed to be linked to the 'd-wave' symmetry of the superconducting state. Angle-resolved photoemission measurements in the superconducting state have revealed a quasiparticle spectrum with a d-wave gap structure that exhibits a maximum along the antinodal direction and vanishes along the nodal direction. Subsequent measurements have shown that, at low doping levels, this gap structure persists even in the high-temperature metallic state, although the nodal points of the superconducting state spread out in finite 'Fermi arcs'. This is the so-called pseudogap phase, and it has been assumed that it is closely linked to the superconducting state, either by assigning it to fluctuating superconductivity or by invoking orders which are natural competitors of d-wave superconductors. Here we report experimental evidence that a very similar pseudogap state with a nodal-antinodal dichotomous character exists in a system that is markedly different from a superconductor: the ferromagnetic metallic groundstate of the colossal magnetoresistive bilayer manganite La1.2Sr1.8Mn2O7. Our findings therefore cast doubt on the assumption that the pseudogap state in the copper oxides and the nodal-antinodal dichotomy are hallmarks of the superconductivity state.

Multiple bosonic mode coupling in the electron self-energy of (La2-xSrx)CuO4

High resolution angle-resolved photoemission spectroscopy data along the (0,0)-(pi,pi) nodal direction with significantly improved statistics reveal fine structure in the electron self-energy of the underdoped (La2-xSrx)CuO4 samples in the normal state. Fine structure at energies of (40-46) meV and (58-63) meV, and possible fine structure at energies of (23-29) meV and (75-85) meV, have been identified. These observations indicate that, in (La2-xSrx)CuO4, more than one bosonic modes are involved in the coupling with electrons.

[Analysis of changes of color Doppler flow imaging in age-related macular degeneration]

OBJECTIVE

To study the specific imaging of age-related macular degeneration (AMD) by color Doppler flow imaging (CDFI).

METHODS

Routine CDFI was carried out in 98 cases of AMD to observe the character of blood flow in AMD, to establish the diagnosis criteria of different types of AMD and to different the AMD from malignant choroidal melanoma, metastatic carcinoma of the choroid, choroidal nevus and macular edema.

RESULTS

CDFI in dry form AMD did not detect changes in most patients, mildly elevated lesions presented in some cases. In wet form of AMD, CDFI showed solid lesion with irregular surface contour. The internal structure of these lesions was middle degree. Choroidal excavation was not found. Numerous blood flow signals could be found at the base of the lesion. Spot blood flow signals were present on the surface of the lesion. There was no abnormal blood flow signal in the mass. The different acoustic properties between wet form and dry form included configuration, surface and internal structure, with or without vitreous hemorrhage.

CONCLUSION

CDFI is a simple and reliable method in the diagnosis of AMD.

Orientation-dependent C60 electronic structures revealed by photoemission spectroscopy

We observe, with angle-resolved photoemission, a dramatic change in the electronic structure of two C60 monolayers, deposited, respectively, on Ag (111) and (100) substrates, and similarly doped with potassium to half filling of the C60 lowest unoccupied molecular orbital. The Fermi surface symmetry, the bandwidth, and the curvature of the dispersion at Gamma point are different. Orientations of the C60 molecules on the two substrates are known to be the main structural difference between the two monolayers, and we present new band-structure calculations for some of these orientations. We conclude that orientations play a key role in the electronic structure of fullerides.

Fermi surface reconstruction in the CDW state of CeTe3 observed by photoemission

CeTe3 is a layered compound where an incommensurate charge density wave (CDW) opens a large gap ( approximately 400 meV) in optimally nested regions of the Fermi surface (FS), whereas other sections with poorer nesting remain ungapped. Through angle-resolved photoemission, we identify bands backfolded according to the CDW periodicity. They define FS pockets formed by the intersection of the original FS and its CDW replica. Such pockets illustrate very directly the role of nesting in the CDW formation but they could not be detected so far in a CDW system. We address the reasons for the weak intensity of the folded bands, by comparing different foldings coexisting in CeTe3.

Dichotomy between nodal and antinodal quasiparticles in underdoped (La2-xSrx)CuO4 superconductors

High resolution angle-resolved photoemission measurements on an underdoped (La(2-x)Srx)CuO4 system show that, at energies below 70 meV, the quasiparticle peak is well defined around the (pi/2,pi/2) nodal region and disappears rather abruptly when the momentum is changed from the nodal point to the (pi,0) antinodal point along the underlying "Fermi surface." It indicates that there is an extra low energy scattering mechanism acting upon the antinodal quasiparticles. We propose that this mechanism is the scattering of quasiparticles across the nearly parallel segments of the Fermi surface near the antinodes.

Direct extraction of the Eliashberg function for electron-phonon coupling: a case study of Be(10(-)10)

We propose a systematic procedure to directly extract the Eliashberg function for electron-phonon coupling from high-resolution angle-resolved photoemission measurement. The procedure is successfully applied to the Be(10(-)10) surface, providing new insights into electron-phonon coupling at this surface. The method is shown to be robust against imperfections in experimental data and suitable for wider applications.

Metallic behavior of lightly doped La2-xSrxCuO4 with a Fermi surface forming an arc

Lightly doped La2-xSrxCuO4 in the so-called "insulating" spin-glass phase has been studied by angle-resolved photoemission spectroscopy. We have observed that a "quasiparticle" (QP) peak crosses the Fermi level in the node direction of the d-wave superconducting gap, forming an "arc" of Fermi surface, which explains the metallic behavior at high temperatures of the lightly doped materials. The QP spectral weight of the arc smoothly increases with hole doping, which we attribute to the n approximately x behavior of the carrier number in the underdoped and lightly doped regions.