Evolution of superconductivity in K2-xFe4+ySe5: Spectroscopic studies of X-ray absorption and emission.

This study investigates the evolution of superconductivity in K2-xFe4+ySe5 using temperature-dependent X-ray absorption and resonant inelastic X-ray scattering techniques. Magnetization measurements show that polycrystalline superconducting (SC) K1.9Fe4.2Se5 has a critical temperature (T c) of ∼31 K with a varying superconducting volume fraction, which strongly depends on its synthesis temperature. An increase in Fe-structural/vacancy disorder in SC samples with more Fe atoms occupying vacant 4d sites is found to be closely related to the decrease in the spin magnetic moment of Fe. Moreover, the nearest-neighbor Fe-Se bond length in SC samples exceeds that in the non-SC (NS) sample, K2Fe4Se5, which indicates a weaker hybridization between the Fe 3d and Se 4p states in SC samples. These results clearly demonstrate the correlations among the local electronic and atomic structures and the magnetic properties of K2-xFe4+ySe5 superconductors, providing deeper insight into the electron pairing mechanisms of superconductivity.

Antibacterial activity of viable and heat-killed probiotic strains against oral pathogens.

Probiotics can stabilize gut flora, regulate intestinal immunity and protect the host from enteric diseases; however, their roles in oral health have received little attention compared to their roles in gut health. Nowadays, the prevalence of sugar-sweetened foods and abuse of antibiotics contribute towards dysbiosis of oral microbiota and drug resistance development in oral pathogens, resulting in various intractable oral diseases. We screened the antibacterial activities of viable and heat-killed probiotic strains against the oral pathogens Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans. The probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 displayed strong antipathogenic activities, whereas heat-killed AP-32, CT-53 and ET-66 displayed high levels of pathogen inhibition. The antibacterial activities of these probiotics were not associated with their H2 O2 production; L. acidophilus TYCA02 produced high levels of H2 O2 but merely exhibited moderate antibacterial activities. Oral tablets containing probiotics showed positive inhibitory effects against oral pathogens, particularly those containing viable probiotics. Our results indicate that probiotics prevent the growth of oral pathogens and improve oral health, providing insights into the antipathogenic efficacy of different probiotic species and their potential role in functional foods that improve oral health. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study provides insights into the antipathogenic efficacy of different probiotic species and their potential roles in developing functional foods to improve oral health. We showed that the probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 have great potential for use in the development of functional foods to improve oral health. Since active probiotics may provide strong and long-term protection, the development of functional food products should favour the use of viable bacteria.

Synthesis of Pt doped Bi2O3/RuO2 photocatalysts for hydrogen production from water splitting using visible light.

This study was focused on the preparation of modified bismuth oxide photocatalysts, including Ru and Pt doped Bi2O3, using sonochemically assisted method to enhance their photocatalytic activity. The crystalline phase composition and surface structure of Bi2O3 photocatalysts were examined using SEM, XRD, UV-visible spectroscopy, and XPS. Optical characterizations have indicated that the Bi2O3 presents the photoabsorption properties shifting from UV light region into visible light which is approaching towards the edge of 470 nm. According to the experimental results, visible-light-driven photocatalysis for water splitting with the addition of 0.3 M Na2SO3 and 0.03 M H2C2O4 as sacrificing agents demonstrates that Pt/Bi2O3-RuO2 catalyst could increase the amount of hydrogen evolution, which is around 11.6 and 14.5 micromol g(-1) h(-1), respectively. Plausible formation mechanisms of modified bismuth oxide and reaction mechanisms of photocatalytic water splitting have been proposed.

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

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

The effect of orbital-lattice coupling on the electrical resistivity of YBaCuFeO5 investigated by X-ray absorption.

Temperature-dependent X-ray absorption near-edge structures, X-ray linear dichroism (XLD) and extended X-ray absorption fine structure (EXAFS) spectroscopic techniques were used to investigate the valence state, preferred orbital and local atomic structure that significantly affect the electrical and magnetic properties of a single crystal of YBaCuFeO5 (YBCFO). An onset of increase of resistivity at ~180 K, followed by a rapid increase at/below 125 K, is observed. An antiferromagnetic (AFM)-like transition is close to the temperature at which the resistivity starts to increase in the ab-plane and is also observed with strong anisotropy between the ab-plane and the c-axis. The XLD spectra at the Fe L3,2-edge revealed a change in Fe 3d eg holes from the preferential [Formula: see text] orbital at high temperature (300-150 K) to the [Formula: see text] orbital at/below 125 K. The analysis of the Fe K-edge EXAFS data of YBCFO further revealed an unusual increase in the Debye-Waller factor of the nearest-neighbor Fe-O bond length at/below 125 K, suggesting phonon-softening behavior, resulting in the breaking of lattice symmetry, particularly in the ab-plane of Fe-related square pyramids. These findings demonstrate a close correlation between electrical resistivity and coupling of the preferred Fe 3d orbital with lattice distortion of a single crystal of YBCFO.

Anisotropy in the magnetic interaction and lattice-orbital coupling of single crystal Ni3TeO6.

This investigation reports on anisotropy in the magnetic interaction, lattice-orbital coupling and degree of phonon softening in single crystal Ni3TeO6 (NTO) using temperature- and polarization-dependent X-ray absorption spectroscopic techniques. The magnetic field-cooled and zero-field-cooled measurements and temperature-dependent Ni L3,2-edge X-ray magnetic circular dichroism spectra of NTO reveal a weak Ni-Ni ferromagnetic interaction close to ~60 K (TSO: temperature of the onset of spin ordering) with a net alignment of Ni spins (the uncompensated components of the Ni moments) along the crystallographic c-axis, which is absent from the ab-plane. Below the Néel temperature, TN~ 52 K, NTO is stable in the antiferromagnetic state with its spin axis parallel to the c-axis. The Ni L3,2-edge X-ray linear dichroism results indicate that above TSO, the Ni 3d eg electrons preferentially occupy the out-of-plane 3d3z2-r2 orbitals and switch to the in-plane 3dx2-y2 orbitals below TSO. The inherent distortion of the NiO6 octahedra and anisotropic nearest-neighbor Ni-O bond lengths between the c-axis and the ab-plane of NTO, followed by anomalous Debye-Waller factors and orbital-lattice in conjunction with spin-phonon couplings, stabilize the occupied out-of-plane (3d3z2-r2) and in-plane (3dx2-y2) Ni eg orbitals above and below TSO, respectively.

Origin of magnetic properties in carbon implanted ZnO nanowires.

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

Electronic and atomic structures of the Sr3Ir4Sn13 single crystal: A possible charge density wave material.

X-ray scattering (XRS), x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) spectroscopic techniques were used to study the electronic and atomic structures of the high-quality Sr3Ir4Sn13 (SIS) single crystal below and above the transition temperature (T* ≈ 147 K). The evolution of a series of modulated satellite peaks below the transition temperature in the XRS experiment indicated the formation of a possible charge density wave (CDW) in the (110) plane. The EXAFS phase derivative analysis supports the CDW-like formation by revealing different bond distances [Sn1(2)-Sn2] below and above T* in the (110) plane. XANES spectra at the Ir L3-edge and Sn K-edge demonstrated an increase (decrease) in the unoccupied (occupied) density of Ir 5d-derived states and a nearly constant density of Sn 5p-derived states at temperatures T < T* in the (110) plane. These observations clearly suggest that the Ir 5d-derived states are closely related to the anomalous resistivity transition. Accordingly, a close relationship exists between local electronic and atomic structures and the CDW-like phase in the SIS single crystal.

Anisotropy in the thermal hysteresis of resistivity and charge density wave nature of single crystal SrFeO3-δ: X-ray absorption and photoemission studies.

The local electronic and atomic structures of the high-quality single crystal of SrFeO3-δ (δ~0.19) were studied using temperature-dependent x-ray absorption and valence-band photoemission spectroscopy (VB-PES) to investigate the origin of anisotropic resistivity in the ab-plane and along the c-axis close to the region of thermal hysteresis (near temperature for susceptibility maximum, Tm~78 K). All experiments herein were conducted during warming and cooling processes. The Fe L 3,2-edge X-ray linear dichroism results show that during cooling from room temperature to below the transition temperature, the unoccupied Fe 3d e g states remain in persistently out-of-plane 3d 3z2-r2 orbitals. In contrast, in the warming process below the transition temperature, they change from 3d 3z2-r2 to in-plane 3d x2-y2 orbitals. The nearest-neighbor (NN) Fe-O bond lengths also exhibit anisotropic behavior in the ab-plane and along the c-axis below Tm. The anisotropic NN Fe-O bond lengths and Debye-Waller factors stabilize the in-plane Fe 3d x2-y2 and out-of-plane 3d 3z2-r2 orbitals during warming and cooling, respectively. Additionally, a VB-PES study further confirms that a relative band gap opens at low temperature in both the ab-plane and along the c-axis, providing the clear evidence of the charge-density-wave nature of SrFeO3-δ (δ~0.19) single crystal.

Understanding of sub-band gap absorption of femtosecond-laser sulfur hyperdoped silicon using synchrotron-based techniques.

The correlation between sub-band gap absorption and the chemical states and electronic and atomic structures of S-hyperdoped Si have been extensively studied, using synchrotron-based x-ray photoelectron spectroscopy (XPS), x-ray absorption near-edge spectroscopy (XANES), extended x-ray absorption fine structure (EXAFS), valence-band photoemission spectroscopy (VB-PES) and first-principles calculation. S 2p XPS spectra reveal that the S-hyperdoped Si with the greatest (~87%) sub-band gap absorption contains the highest concentration of S(2-) (monosulfide) species. Annealing S-hyperdoped Si reduces the sub-band gap absorptance and the concentration of S(2-) species, but significantly increases the concentration of larger S clusters [polysulfides (Sn(2-), n > 2)]. The Si K-edge XANES spectra show that S hyperdoping in Si increases (decreased) the occupied (unoccupied) electronic density of states at/above the conduction-band-minimum. VB-PES spectra evidently reveal that the S-dopants not only form an impurity band deep within the band gap, giving rise to the sub-band gap absorption, but also cause the insulator-to-metal transition in S-hyperdoped Si samples. Based on the experimental results and the calculations by density functional theory, the chemical state of the S species and the formation of the S-dopant states in the band gap of Si are critical in determining the sub-band gap absorptance of hyperdoped Si samples.

Visualizing chemical states and defects induced magnetism of graphene oxide by spatially-resolved-X-ray microscopy and spectroscopy.

This investigation studies the various magnetic behaviors of graphene oxide (GO) and reduced graphene oxides (rGOs) and elucidates the relationship between the chemical states that involve defects therein and their magnetic behaviors in GO sheets. Magnetic hysteresis loop reveals that the GO is ferromagnetic whereas photo-thermal moderately reduced graphene oxide (M-rGO) and heavily reduced graphene oxide (H-rGO) gradually become paramagnetic behavior at room temperature. Scanning transmission X-ray microscopy and corresponding X-ray absorption near-edge structure spectroscopy were utilized to investigate thoroughly the variation of the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups, as well as the C 2p(σ*)-derived states in flat and wrinkle regions to clarify the relationship between the spatially-resolved chemical states and the magnetism of GO, M-rGO and H-rGO. The results of X-ray magnetic circular dichroism further support the finding that C 2p(σ*)-derived states are the main origin of the magnetism of GO. Based on experimental results and first-principles calculations, the variation in magnetic behavior from GO to M-rGO and to H-rGO is interpreted, and the origin of ferromagnetism is identified as the C 2p(σ*)-derived states that involve defects/vacancies rather than the C 2p(π*) states that are bound with oxygen-containing and hydroxyl groups on GO sheets.

Suggestive evidence for linkage of schizophrenia to markers at chromosome 15q13-14 in Taiwanese families.

In order to evaluate the linkage of schizophrenia to loci at chromosome 15q, we genotyped six microsatellite markers at chromosome 15q11-14 in 52 Taiwanese schizophrenic families. Two phenotype models (narrow: DSM-IV schizophrenia only; and broad: including schizophrenia, schizoaffective, and other nonaffective psychotic disorders) were used to define the disease phenotype. Maximum nonparametric linkage scores (NPL scores) of 3.33 (P = 0.0003) and 2.96 (P = 0.0008) were obtained at the marker D15S976 under broad and narrow models, respectively. Positive linkage results were also observed at the marker D15S1360, previously reported to have significant linkage to a neurophysiological deficit of schizophrenia, with NPL scores of 2.71 (P = 0.003) and 2.78 (P = 0.002) under broad and narrow models, respectively. The results provide suggestive linkage evidence of schizophrenia to loci at chromosome 15q13-14 in an ethnically distinct Taiwanese sample.

Antisense oligodeoxynucleotides of IGF-II selectively inhibit growth of human hepatoma cells overproducing IGF-II.

Insulin-like growth factor II (IGF-II) is expressed in many developing embryonic tissues and is involved in mammalian growth and development. After birth, serum IGF-II is mainly produced by liver cells. Many reports have indicated that IGF-II is overexpressed in some hepatocellular carcinoma (HCC) tissue. These findings imply the possible importance of this growth factor in carcinogenesis. We screened four human HCC cell lines and three rat HCC cell lines and found that HuH-7 and HepG2 cells produced fivefold more intracellular IGF-II than the other cell lines. Experimental data indicate that IGF-II functions through the intracrine mode for HuH-7 cells. To study whether the overexpression of IGF-II is significant for the growth of HCC or only a consequence of HCC development, we used antisense oligodeoxynucleotides (ATON) to arrest the translation of IGF-II mRNA, and then measured the effects on cell growth. We found that the production of IGF-II was suppressed by ATON, and the decrease of IGF-II resulted in growth inhibition of HuH-7 and HepG2. ATON had no effect on the other tested cell lines, which produced lower levels of IGF-II. The growth inhibition was mainly attributed to a decrease of cell proliferative activity. The results indicate that the IGF-II-overproducing cell lines do depend on IGF-II for growth, and ATON of IGF-II can selectively inhibit the growth of these cells. ATON may be a potential therapeutic agent for this type of HCC in vivo.

Asymmetric trialkylaluminium addition to aldehydes catalyzed by titanium complexes of N-sulfonylated amino alcohols with two stereogenic centers.

The asymmetric methylation, ethylation and allylation of aldehydes using trialkylaluminium reagents catalyzed by titanium(IV) complexes of N-sulfonylated amino alcohols gave excellent enantioselectivities of up to 99% ee.

Galectin-1, a novel ligand of neuropilin-1, activates VEGFR-2 signaling and modulates the migration of vascular endothelial cells.

Galectin-1 (Gal-1), a homodimeric prototype of the galectins with a single carbohydrate-recognition domain, was recently identified as being overexpressed in tumor-associated capillary endothelial cells. The role of Gal-1 in endothelial cellular functions and the mechanism of action of Gal-1 remain unknown. Neuropilin-1 (NRP1) is a neuronal receptor that mediates repulsive growth cone guidance, and NRP1 functions in endothelial cells as a coreceptor (with vascular endothelial growth factor receptors (VEGFRs)) for VEGF(165). In this study, we found that Gal-1 was overexpressed in the tumor-associated endothelial cells of oral squamous cell carcinomas (P<0.001). Gal-1 increased the proliferation and adhesion of endothelial cells, and enhanced cell migration in combination with VEGF(165). Surprisingly, Gal-1 selectively bound NRP1 via the carbohydrate-recognition domain, but did not bind VEGFR-1, VEGFR-2 or VEGFR-3. The Gal-1-NRP1 interaction mediated the migration and adhesion of endothelial cells. The binding of Gal-1 to NRP1 enhanced VEGFR-2 phosphorylation and stimulated the activation of the mitogen activated protein (MAP) kinases SAPK1/JNK (stress activated protein kinase-1/c-Jun NH2-terminal kinase). These findings show, for the first time, that Gal-1 can directly bind to NRP1 on endothelial cells, and can promote the NRP1/VEGFR-2-mediated signaling pathway as well as NRP1-mediated biological activities.

An integrated healthcare enterprise information portal and healthcare information system framework.

The paper presents an integrated, distributed Healthcare Enterprise Information Portal (HEIP) and Hospital Information Systems (HIS) framework over wireless/wired infrastructure at National Taiwan University Hospital (NTUH). A single sign-on solution for the hospital customer relationship management (CRM) in HEIP has been established. The outcomes of the newly developed Outpatient Information Systems (OIS) in HIS are discussed. The future HEIP blueprints with CRM oriented features: e-Learning, Remote Consultation and Diagnosis (RCD), as well as on-Line Vaccination Services are addressed. Finally, the integrated HEIP and HIS architectures based on the middleware technologies are proposed along with the feasible approaches. The preliminary performance of multi-media, time-based data exchanges over the wireless HEIP side is collected to evaluate the efficiency of the architecture.

[Low dose radioiodine treatment of papillary thyroid carcinoma in a child--a case report].

The thyroid carcinoma is rare in children and the optimal management is rather controversial. We report a case of a 7-year-old boy who had right neck masses and proved to be papillary thyroid carcinoma after near-total thyroidectomy. Post-operative 20 mCi radioiodine-131 (I-131) ablation scan, lung metastasis was suspected but the chest X ray was normal. After being lost to follow up for 4 years, the patient returned with the complaints of cough; the chest X ray was still normal. He then received 5 treatment with low dose (30 mCi) I-131 therapy and continued thyroxine replacement. Progressive decrease both of the thyroglobulin level and the intensity of radioactivity of lung were noted. After a total doses of 193 mCi I-131 therapy, neither pulmonary fibrosis nor bone marrow suppression was seen. Although the low dose (< or = 30 mCi) I-131 therapy was recommended, it was limited for the ablation therapy of the remnant thyroid tissue. Upon consideration of economics and the convenience of not being admitted to the isolation room, the low dose I-131 therapy seems feasible for children with thyroid carcinoma with systemic disease. However, the long term efficacy needs further evaluation.

Outcome after treatment for papillary thyroid cancer.

BACKGROUND: To evaluate the results of treatment and the prognostic variables of papillary thyroid carcinoma patients after long-term follow-up. PATIENTS AND METHODS: Retrospective review of 1,373 thyroid cancer patients. Of the 1,016 papillary thyroid cancer patients, 394 patients received follow-up for more than 5 years, including 305 women (mean age, 38.4 +/- 13.7 years) and 89 men (mean age, 44.0 +/- 13.4 years). Of these papillary thyroid carcinoma patients, 227, 76, 68, and 23 patients were categorized in clinical stages I, II, III, and IV, respectively, at the time of diagnosis. RESULTS: After treatment, 36 (9.1%) patients died. Only 23 (5.8%) of them died of papillary thyroid carcinoma. The 1-, 5-, 10-, and 20-year survival rates were 0.980, 0.951, 0.901, and 0.731. Mortality factors of the papillary thyroid carcinoma patients related to age, gender, tumor size, and postoperative serum thyroglobulin (Tg) levels. Twenty-four patients progressed from clinical stages I, II, and III to stage IV during the follow-up period. Of these 24 patients, 12 died during the follow-up period. In this study, age, gender, 131I accumulated dose, postoperative serum Tg levels, and the survival rate were demonstrated to be statistically significant between the patients in early stage and advanced stage groups after treatment. CONCLUSION: Twenty-four of the 47 papillary thyroid cancer patients with distant metastases were diagnosed during the follow-up period. This study suggests that distant metastasis may occur at a serum Tg level of 2.3 ng/mL with thyroxine replacement. Postoperative long-term close follow-up of these patients is recommended.

In vitro and in vivo suppression of growth of rat liver epithelial tumor cells by antisense oligonucleotide against protein kinase C-alpha.

BACKGROUND/AIMS: It has been hypothesized that liver stem cells may be activated and proliferate upon liver injury and may participate in the development of liver cancer. GP7TB, a rat liver epithelial tumor cell line, possesses characteristics of liver stem-like cells and can develop into a tumor in syngeneic Fischer 344 rat. We found that protein kinase C-alpha (PKC-alpha) is overexpressed in GP7TB cells. The importance of PKC-alpha for this liver tumor cell was elucidated. METHODS: Antisense oligonucleotide (ODN) was applied to suppress the production of PKC-alpha in GP7TB cells in vitro and in vivo. Cell viability was measured by acid phosphatase assay. The cellular levels of PKC-alpha and Bcl-2 were monitored by Western-blot analysis. Activation of nuclear factor NF-kappaB was analyzed by electrophoretic mobility shift assay. Cell cycle phase distribution was monitored by FACScan. Cell apoptosis was detected by TUNEL assay and histochemical staining of tumor tissue sections. The in vivo experiment was conducted by implanting tumor mass of GP7TB in the liver of F-344 rat and continuous delivery of the ODN by a mini-osmotic pump. RESULTS: Antisense ODN effectively suppressed the level of PKC-alpha that resulted in the decrease of Bcl-2 and nuclear NF-kappaB. The cumulative viable cells also decreased dramatically for the antisense-treated group. FACScan showed that the cells were arrested at early S-phase. These cells in turn went into apoptosis without completing a cell cycle. It was found that growth of the tumor was suppressed efficiently by antisense ODN. Cell apoptosis was found in the orthotopic tumor. The normal liver cells were not affected. CONCLUSIONS: A lethal effect of depressing the level of PKC-alpha in GP7TB cells and success in suppressing orthotopic tumor growth in vivo suggests that PKC-alpha antisense ODN would be a promising therapeutic agent for some liver cancers.