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High mobility group box 1 (HMGB1), a protein with important functions, has been recognized as a potential therapeutic target for the treatment of sepsis. One possible mechanism for this is that inhibiting HMGB1 secretion can exert antiseptic effects, which can restore the integrity of the vascular barrier. (7S)-(+)-cyclopentyl carbamic acid 8,8-dimethyl-2-oxo-6,7-dihydro-2H,8H-pyrano[3,2-g]chromen-7-yl-ester (CGK012) is a newly synthesized pyranocoumarin compound that could function as a novel small-molecule inhibitor of the Wnt/β-catenin signaling pathway. However, no studies have yet determined the effects of CGK012 on sepsis. We investigated the potential of CGK012 to attenuate the excessive permeability induced by HMGB1 and enhance survival rates in a mouse model of sepsis with reduced HMGB1 levels following lipopolysaccharide (LPS) treatment. In both LPS-stimulated human endothelial cells and a mouse model exhibiting septic symptoms due to cecal ligation and puncture (CLP), we assessed proinflammatory protein levels and tissue damage biomarkers as indicators of reduced vascular permeability. CGK012 was applied after induction in human endothelial cells exposed to LPS and the CLP-induced mouse model of sepsis. CGK012 effectively mitigated excessive permeability and suppressed HMGB1 release, resulting in improved vascular stability, decreased mortality, and enhanced histological conditions in the mouse model of CLP-induced sepsis. In conclusion, our findings indicate that CGK012 treatment in mice with CLP-induced sepsis diminished HMGB1 release and increased the survival rate, suggesting its potential as a pharmaceutical intervention for sepsis. [ABSTRACT FROM AUTHOR]

A small natural substance called cirsilineol (CSL), which was discovered in the plant Artemisia vestita, is lethal to many cancer cells and has antioxidant, anticancer, and antibacterial properties. Here, we investigated the underlying mechanisms of the antithrombotic action of CSL. We demonstrated that CSL has antithrombotic efficacy comparable to rivaroxaban, a direct blood coagulation factor Xa (FXa) inhibitor employed as a positive control, in inhibiting the enzymatic activity of FXa and the platelet aggregation induced by adenosine diphosphate (ADP) and U46619, a thromboxane A2 analog. The expression of P-selectin, the phosphorylation of myristoylated alanine-rich C kinase substrate by U46619 or ADP, and the activation of PAC-1 in platelets were inhibited by CSL. Nitric oxide production was increased by CSL in ADP- or U46619-treated human umbilical vein endothelial cells (HUVECs), although excessive endothelin-1 secretion was suppressed. CSL demonstrated strong anticoagulant and antithrombotic effects in a mouse model of arterial and pulmonary thrombosis. Our findings suggest that CSL is a potential pharmacological candidate for a novel class of anti-FXa and antiplatelet medications. [ABSTRACT FROM AUTHOR]

Cd‐S‐Se quantum dot embedded glasses (QDEGs) with dual‐band emissions of green and red were synthesized by assembling two QDEGs, to obtain a color converter for white LEDs (wLEDs) with a wide color gamut and long‐term stability. Each QDEG, possessing different sizes of QD, was prepared by adjusting heat‐treatment conditions. They were then bonded to each other by an additional heat treatment to fabricate a pattern structured QDEG (pQDEG). The fabrication conditions of the pQDEGs, such as their heat‐treatment condition and thickness, were varied to improve the color gamut. pQDEG‐based WLEDs were demonstrated and their optical properties such as color coordinates, luminous efficiency, and color rendering index (CRI) were monitored. The effect of pQDEG fabrication conditions on the resultant emission spectra and color gamut were discussed. [ABSTRACT FROM AUTHOR]

Heavy metal oxide glasses containing GeO[SUB2] were investigated as potential hosts for 1.48 μm fiber-optic amplifiers because of their low phonon energy. Addition of ⩾ 10 mol % GeO[SUB2] to 0.57PbO-0.25Bi[SUB2]O[SUB3] - 0.18Ga[SUB2]O[SUB3] (mole fraction) glass provided thermal stability as well as good emission properties. The optimum glass composition for 1.48 mm amplifiers, considering lifetimes and population of the Tm[SUB3+]:[SUP3]H[SUB4] level, was 0.8 (0.57PbO-0.25Bi[SUB2]O[SUB3] - (0.18Ga[SUB2]O[SUB3] - 0.2GeO[SUB2] (mole fraction). As the concentration of codoped Ho[SUP3+] exceeded 0.2 mol %, the population density of the Tm[SUP3+]:[SUP3]H[SUB4] level decreased sharply and the population inversion between the [SUP3]H[SUB4] and [SUP3]F[SUB4] levels in Tm[SUP3+] was achieved. [ABSTRACT FROM AUTHOR]

Low-temperature midinfrared emission properties of Pr[sup 3+]-doped Ge[sub 30]Ga[sub 2]As[sub 6]S[sub 62] and Ge[sub 28]Ga[sub 5]As[sub 12]Se[sub 55] glasses (at. %) were investigated. Emissions centered at 3400 and 4700 nm were clearly observed from sulfide and selenide glasses, respectively, when the specimens were cooled to 20 K. The measured lifetime of the [sup 1]G[sub 4] level in sulfide glass increased from 320 μs at room temperature to 400 μs at 20 K. The intensity and quantum efficiency of the emission from the Pr[sup 3+]:([sup 3]F[sub 3], [sup 3]F[sub 4]) level in selenide glass also increased as the temperature decreased to 120 K. The enhancement resulted from a decrease in nonradiative multiphonon relaxation at low temperatures. The temperature dependence of the multiphonon relaxation rates indicated that the asymmetrical stretching vibration of GeS[sub 4] tetrahedra (375 cm-1) is primarily responsible for the multiphonon relaxation process in sulfide glass. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Spectroscopic properties and room-temperature persistent spectral hole burning mechanisms of Eu[sup 3+] -doped borate glasses were investigated. The depth of the burnt hole increased K. The photoreduction of Eu[sup 3+] to Eu[sup 2+] is a primary mechanism of hole burning and this hypothesis was supported by spectral hole properties, relaxation properties as well as changes in the local structure of Eu[sup 3+] in glasses. [ABSTRACT FROM AUTHOR]

Efficient persistent spectral hole burning in Eu[sup 3+]-doped sulfide glasses was observed with the addition of CsBr or KBr. Holes in these glasses showed high initial growth rates, thermal barrier heights, and low relaxation rates. It was also possible to form independent multiholes on the inhomogeneously broadened absorption spectrum. One-photon absorption of the burning light and corresponding reduction of Eu[sup 3+] into Eu[sup 2+] via interaction with local conduction (or charge transfer) bands are the main processes for hole burning. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) is a potent transcription factor for mitochondrial function, lipid metabolism, and detoxification in a variety of tissues. PGC1α also promotes brain cell proliferation and memory. However, how PGC1α is involved in aging is not well known. In brain endothelial cells, we found that PGC1α knockdown accelerated DNA damage-induced senescence, evidenced by an increase in senescence-associated β-galactosidase-positive cells and a decrease in cell proliferation and adenosine triphosphate production. PGC1α knockdown delayed DNA damage repair mechanisms compared with the wild-type condition as shown by γ-H2AX foci staining assay. Overexpression of PGC1α reduced senescence-associated β-galactosidase-positive cells and increased the proliferation of senescent cells. Although PGC1α protein levels were not decreased, PGC1 acetylation was increased by ionizing radiation treatment and aging. Histone deacetylase 1 (HDAC1) expression was decreased by ionizing radiation treatment and aging, and downregulation of HDAC1 induced acetylation of PGC1α. HDAC1 knockdown affected sirtuin 1 expression and decreased its deacetylation of PGC1α. In the mouse brain cortex, acetylation of PGC1α was increased by ionizing radiation treatment. These results suggest that acetylation of PGC1α is induced by DNA damage agents such as ionizing radiation, which deregulates mitochondrial mechanisms and metabolism, resulting in acceleration of radiation-induced senescence. Therefore, acetylation of PGC1α may be a cause of brain disorders and has the potential to serve as a therapeutic target for radiation-induced senescence after radiation cancer therapy. [ABSTRACT FROM AUTHOR]

Abstract: Fluorescence intensity ratios (FIRs) of the 640 nm and 602 nm emissions from Sm3+ were recorded at various temperatures T to identify the temperature increases ΔT associated with laser‐induced local heating of Ag nanoparticles. The FIRs increased as intensities of the excitation beam from a 532‐nm continuous‐wave laser increased. Estimated T of the irradiated region increased to as high as 586°C when at laser irradiation of 1.5 W on the surface containing Ag nanoparticles. Local heating due to the surface plasmon resonance of Ag nanoparticles is a main reason for the ΔT that eventually leads to precipitation of PbS quantum dots in glasses. [ABSTRACT FROM AUTHOR]

Glass-ceramics containing calcium neodymium(cerium) oxide silicate [Ca 2 Nd 8-x Ce x (SiO 4 ) 6 O 2 ] crystals were fabricated for the immobilization of radioactive wastes that contain large portions of rare-earth ions. Controlled crystallization of alkali borosilicate glasses by heating at T ≥ 750 °C for 3 h formed hexagonal Ca–silicate crystals. Maximum lanthanide oxide waste loading was >26.8 wt.%. Ce and Nd ions were highly partitioned inside Ca–silicate crystals compared to the glass matrix; the rare-earth wastes are efficiently immobilized inside the crystalline phases. The concentrations of Ce and Nd ions released in a material characterization center-type 1 test were below the detection limit (0.1 ppb) of inductively coupled plasma mass spectroscopy. Normalized release values performed by a product consistency test were 2.64·10 −6 g m −2 for Ce ion and 2.19·10 −6 g m −2 for Nd ion. Results suggest that glass-ceramics containing calcium neodymium(cerium) silicate crystals are good candidate wasteforms for immobilization of lanthanide wastes generated by pyro-processing. [ABSTRACT FROM AUTHOR]

Modulation of the band gap energy and diameter of quantum dots (QDs) formed in glasses is important to achieve the optimized performance for applications as infrared light sources, lasers, saturable absorbers, etc. Absorption and photoluminescence of PbS QDs were extended into mid-infrared wavelength range in glasses containing small amount of lead but oversaturated with sulfur. Dual-band photoluminescence of PbSe QDs was prepared in oxyfluoride glass-ceramics containing BaF2 nanocrystals. By introducing SnO in the glasses, alloyed Pb1-xSnxSe QDs with smaller band gap energies were formed in glasses, and mid-infrared photoluminescence of Pb1-xSnxSe QDs at ~2570 nm in wavelength was achieved. [ABSTRACT FROM AUTHOR]

Glass-ceramic wasteforms containing vitusite (Na 3 Ce(PO 4 ) 2 ) and Ce-rich crystals were investigated to immobilize lanthanide oxide wastes generated by pyro-processing. Controlled crystallization of alkali borosilicate glasses containing small amounts of P 2 O 5 by heating at T >600 °C for 3 h resulted in formation of vitusite as a major crystalline phase with a minor Ce-rich crystalline phase. Lanthanide oxide waste loading was 11.87 wt%. Rare-earth wastes were efficiently immobilized inside the crystalline phases: lanthanide elements such as Ce and Nd constituted ~26 wt% of vitusite and 80 wt% of Ce-rich crystals. Amounts of Ce and Nd ions released in a product consistency test were below the detection limit (0.1 ppm) of inductively coupled plasma atomic emission spectroscopy. Glass-ceramic wasteforms that contain vitusite crystals are good candidates to immobilize lanthanide wastes generated by pyro-processing. [ABSTRACT FROM AUTHOR]

Distribution and roles of rare earth ions in fluoride nanocrystals and lead chalcogenide quantum dots formed in glasses are reported. High-resolution transmission electron microscopic analysis and electron energy loss spectroscopic ( EELS) analysis showed that oxyfluoride glasses initially form crystals with high Er3+ content such as PbErF5 during heating and gradually form crystals with low Er3+ concentration. Amount of PbErF5 crystals depended upon the initial concentration of Er3+ ions in the parent glasses. EELS analysis also showed that Nd3+ ions were formed inside PbS quantum dots, supporting the proposition of the formation of Nd-O clusters. [ABSTRACT FROM AUTHOR]

Abstract: Infrared upconversion luminescence properties of Er3+/Yb3+ co-doped oxy-fluoride glasses and glass-ceramics were investigated. Under 1550nm laser excitation, infrared emission centered at ~980nm that originated from the Yb3+: 2F5/2 → 2F7/2 and Er3+: 4I11/2 → 4F15/2 transitions was observed. The upconversion luminescence was enhanced both by Yb3+ content increase and by precipitation of β-PbF2 nano-crystals in the glass matrix. The energy transfer process between Yb3+ and Er3+ ions dominated IR upconversion emission, and Yb3+ can be used as energy acceptor. The strong upconverted luminescence can be used to increase the efficiency of silicon solar cells. [Copyright &y& Elsevier]

Tunable absorption and photoluminescence ( PL) of lead chalcogenide quantum dots ( QDs) doped in glasses due to the quantum confinements effect have been actively investigated for application as saturable absorbers, laser sources, and fiber-optic amplifiers. Optical properties of QDs have been carefully monitored by controlling their sizes through heat treatment and rare-earth ion doping. Two- and three-dimensional precipitation of lead chalcogenide QDs were also realized using silver ion exchange and femtosecond laser irradiation in combination with thermal treatment. Prototypes of microstructured single-mode fibers and tapered fiber amplifiers containing QDs proved potentials of these materials for fiber-optic amplifiers application. Further research works on QD-doped solid core fibers, surface passivation of quantum dots and their application for the mid-infrared optical devices are necessary. [ABSTRACT FROM AUTHOR]

Holliday junction recognition protein (HJURP), a centromere protein-A (CENP-A) histone chaperone, mediates centromere-specific assembly of CENP-A nucleosome, contributing to high-fidelity chromosome segregation during cell division. However, the role of HJURP in cellular senescence of human primary cells remains unclear. We found that the expression levels of HJURP decreased in human dermal fibroblasts and umbilical vein endothelial cells in replicative or premature senescence. Ectopic expression of HJURP in senescent cells partially overcame cell senescence. Conversely, downregulation of HJURP in young cells led to premature senescence. p53 knockdown, but not p16 knockdown, abolished senescence phenotypes caused by HJURP reduction. These data suggest that HJURP plays an important role in the regulation of cellular senescence through a p53-dependent pathway and might contribute to tissue or organismal aging and protection of cellular transformation. [ABSTRACT FROM AUTHOR]

Holliday junction recognition protein (HJURP), a centromere protein-A (CENP-A) histone chaperone, mediates centromere-specific assembly of CENP-A nucleosome, contributing to high-fidelity chromosome segregation during cell division. However, the role of HJURP in cellular senescence of human primary cells remains unclear. We found that the expression levels of HJURP decreased in human dermal fibroblasts and umbilical vein endothelial cells in replicative or premature senescence. Ectopic expression of HJURP in senescent cells partially overcame cell senescence. Conversely, downregulation of HJURP in young cells led to premature senescence. p53 knockdown, but not p16 knockdown, abolished senescence phenotypes caused by HJURP reduction. These data suggest that HJURP plays an important role in the regulation of cellular senescence through a p53-dependent pathway and might contribute to tissue or organismal aging and protection of cellular transformation. [ABSTRACT FROM PUBLISHER]

The angiopoietin/Tie2 system is an important regulator of angiogenesis and inflammation. In addition to its functions in endothelial cells, Tie2 expression on non-endothelial cells allows for angiopoietin ligands to stimulate the cells. Although Ang1 is a strong Tie2 receptor agonist, little is known regarding the effect of Ang1 on non-endothelial cells, such as monocytes and macrophages. In this study, we found that Ang1 functionally binds to and stimulates monocytes via p38 and Erk1/2 phosphorylation. Ang1-mediated monocyte stimulation is associated with proinflammatory cytokine TNF-α expression. We also determined that Ang1 switched macrophage differentiation toward a pro-inflammatory phenotype, even in the presence of an anti-inflammatory mediator. These findings suggest that Ang1 plays a role in stimulating pro-inflammatory responses and could provide a new strategy by which to manage inflammatory responses. [ABSTRACT FROM AUTHOR]

Luminescence of CdS quantum dots ( QDs) enhanced by the induction of Ag nanoparticles ( NPs) in glasses was investigated. Ag+ ions diffused into glasses containing CdS QDs by ion exchange, then formed Ag NPs after subsequent heat treatment. Luminescence intensity of CdS QDs increased approximately three times when the ion-exchange duration was 1 min, but was severely quenched when the duration was extended to 30 min. Increasing the amount of Ag+ ions increased the number of Ag NPs and decreased the average distance between Ag NPs and CdS QDs. This decrease in the average distance induced the changes of luminescence intensity. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we analyzed the chemical composition of fine particulate matter 2.5μm or less (PM2.5) collected at Incheon, the coastal area in Seoul, Korea every third day from June 2009 to May 2010. Based on the analyzed chemical species in the PM2.5 samples, the sources of PM2.5 were identified using a positive matrix factorization (PMF). Nine sources of PM2.5 were determined from PMF analysis. The major sources of PM2.5 were secondary nitrate (25.4%), secondary sulfate (19.0%), motor vehicle 1 (14.8%) with a lesser contribution from industry (8.5%), motor vehicle 2 (8.2%), biomass burning (6.1%), soil (6.1%), combustion and copper production emissions (6.1%), and sea salt (5.9%). From a paired t-test, it was found that yellow sand samples were characterized as having higher contribution from soil sources (p<0.05). Furthermore, the likely source areas of PM2.5 emissions were determined using the conditional probability function (CPF) and the potential source contribution function (PSCF). CPF analysis identified the likely local sources of PM2.5 as motor vehicles and sea salt. PSCF analysis indicated that the likely source areas for secondary particles (sulfate and nitrate) were the major industrial areas in China. Finally, using the source contribution of PM2.5 and associated organic composition data, principal component analysis (PCA) was conducted to evaluate the accuracy of the PM2.5 source apportionments by PMF. The PCA analysis confirmed eight of the nine PM2.5 sources. Our result implies that the chemical composition analysis of PM2.5 data and various modeling techniques can effectively identify the potential contributing sources. [Copyright &y& Elsevier]

A method is reported that uses visible continuous-wave laser to directly fabricate micropatterns in glasses containing silver ( Ag) nanoparticles. Ag nanoparticles were formed in the glass using thermal treatment. Upon laser irradiation, Ag nanoparticles with their surface plasmon in resonance with the laser beam were partially melted and decreased in size due to the temperature increase induced by the excited Ag nanoparticles. Three-dimensional patterns were achieved by scanning the laser beam through the thickness of the glass. [ABSTRACT FROM AUTHOR]

Abstract: We examined the characteristics, sources, and distribution of PM2.5 and carbonaceous species in particulate samples collected from June 2009 to May 2010 in Incheon, Korea. The average PM2.5 concentration (41.9 ± 9.0 μg m−3) exceeded the annual level set by the United States'' National Ambient Air Quality Standards (15 μg m−3). The major fraction of PM2.5 consisted of ionic species (accounting for 38.9 ± 8.8%), such as NO3 −, SO4 2−, and NH4 +, as well as organic carbon (OC) (accounting for 18.9 ± 5.1%). We also analyzed the seasonal variation in PM2.5 and secondary aerosols such as NO3 − and SO4 2− in PM2.5. While SO4 2− concentrations were higher in spring and summer, the concentration of PM2.5 and NO3 − were the highest in winter. SO4 2− concentrations were higher during the spring and summer, but PM2.5 and NO3 − were highest during the winter. As an important aerosol indicator, water-soluble organic carbon (WSOC) (mean 4.7 ± 0.8 μg m−3, 58.9 ± 10.7% of total OC) showed a strong relationship with NO3 −, SO4 2−, and SOC (R 2 = 0.56, 0.67, and 0.65, respectively), which was indicative of favorable conditions for SOC formation during the sampling period. Among the individual organic aerosols measured, n-alkanes, n-alkanoic acids, levoglucosan, and phthalates were major components, whereas PAHs (polycyclic aromatic hydrocarbons), oxy-PAHs, hopanes, and cholestanes were minor components. The concentration of organic compounds during smoggy periods was higher than during non-event periods. The n-alkane and n-alkanoic acid species during the smoggy periods were 10–14 times higher than during the normal period. Using principal component analysis coupled with multiple linear regression analysis, we identified the primary sources of PM2.5 to be motor vehicle/sea salt, secondary organic aerosols, combustion, biogenic/meat cooking, and soil sources. [Copyright &y& Elsevier]

This article reports the effect of Ag+ ion-exchange on the precipitation of PbS quantum dots ( QDs) in silicate glasses. The glasses were subjected to ion-exchange in AgNO3 salt melts at 260°C for 60 s. Ag nanoparticles ( NPs) and PbS QDs precipitated after heat treatment at temperatures of 440°C-460°C for 10 h. Photoluminescence wavelength λPL of PbS QDs was longer (~1525 ≤ λPL ≤ ~1580 nm) in Ag+ ion-exchanged regions than in Ag+-free regions (~1030 ≤ λPL ≤ ~1200 nm). Average diameter D of PbS QDs estimated by calculation and TEM images was larger in Ag+ ion-exchanged regions (~5.2 ≤ D ≤ ~5.5 nm) than in Ag+-free regions (~2.4 ≤ D ≤ ~3.3 nm). Ag NPs that formed during heat treatment provided the sites for heterogeneous nucleation of PbS QDs and promoted the precipitation of PbS QDs in glasses. [ABSTRACT FROM AUTHOR]

Abstract: We experimentally verify that a color center in the form of takes shape in silicate glasses containing relatively small amount of ZnSe which are prepared via a conventional melt-quenching process. Samples also produce broad photoluminescence when excited with UV light source, suggesting potential applications in the visible range. Analyses based on X-ray diffraction patterns, high resolution transmission electron microscopy, and Raman spectroscopy support the formation of color centers in addition to Se nanocrystals. [Copyright &y& Elsevier]

Abstract: Precipitation of PbS quantum dots (QDs) in silicate glasses controlled by Ag+ ion diffusion was investigated. Ag+ ions penetrated ~0.5μm into the glass when the glass was immersed in the AgNO3 solution at 80°C. Ag nano-particles (NPs) and PbS QDs were formed after heat-treatment at temperatures of 420–460°C for 10h. PbS QDs in Ag+-diffused regions photoluminesced at longer wavelengths than did those in Ag+-free regions. This indicates that PbS QDs thus formed in regions containing Ag NPs were larger than those in Ag+-free regions and this size difference was confirmed from the transmission electron microscope images. PbS QDs can grow at temperature as low as 420°C in Ag+-diffused regions and this implies that PbS QDs form preferentially using Ag NPs as nucleating agents. [Copyright &y& Elsevier]

PbS and PbS/CdS core/shell colloidal quantum dots (QDs) were mixed with As 2 S 3 glass powders to prepare solid composite materials. PbS QDs showed an absorption band centered at a wavelength of λ = 1478 nm and a photoluminescence (PL) band centered at λ = 1547 nm. PbS/CdS core/shell QDs had higher PL intensity than did bare PbS QDs. Solid composites made by mixing QDs and As 2 S 3 glass powders showed clear PL bands at λ = 1385 nm. Optical fibers of As 2 S 3 glass can be prepared from these composite materials if appropriate scale-up technology is realized. [ABSTRACT FROM AUTHOR]

Abstract: Optical properties and photoluminescence of PbS quantum dots (QDs) embedded in glasses were investigated. Formation and radius of PbS QDs were carefully controlled though heat-treatment and modification of host glass composition. Heat-treatment conditions for precipitation of 3–10nm radius QDs for the tunable photoluminescence in the 1–2μm wavelength range were identified. Glasses doped with PbS QDs provide potential as robust materials for broadband fiber-optic amplifiers. [Copyright &y& Elsevier]

Abstract: Thermal treatment at 480 °C for 40 h resulted in the precipitation of β-PbF2 nano-crystals inside the oxy-fluoride glasses co-doped with Ho3+, Tm3+ and Yb3+. Generation of white light was achieved through the simultaneous blue, green and red up-converted emissions by pumping at 900 nm. Simulation of sunlight was most successfully achieved with pump power of ∼150 mW. [Copyright &y& Elsevier]

Abstract: Local structures of rare-earth ions in Ge–Ga–S–CsBr glasses were investigated to understand the structural origin on the emission property enhancement. The frequency of the phonon vibration controlling the multiphonon relaxation was changed to 245cm−1 due to the formation of Ga–Br bonds with CsBr addition to sulfide glasses. Formation of this new chemical bond was also confirmed from the phonon side band spectra of Eu3+ ions. Analyses of the EXASF spectra proved that Tm3+ ions were surrounded by approximately seven S ions in Ge0.25Ga0.10S0.65 glass but were coordinated by ∼6 Br ions in the glass with 10mol% of CsBr. [Copyright &y& Elsevier]

Abstract: Transparent nano-crystalline glass–ceramics (nano-structured glasses) were prepared from oxy-fluoride precursor glass doped with HoF3 and their luminescence properties were investigated. Visible blue, green and red emissions were observed, and the relative intensity of the green and red emission was strongly dependent on HoF3 concentration. Under 750 nm pumping, the intense green emission due to the photon avalanche process was observed at room temperature from nano-structured glass doped with high (0.5mol%) concentration of HoF3. [Copyright &y& Elsevier]

Emission properties and energy transfer of PbO-Bi2O3-Ga2O3-GeO2 glasses codoped with Tm3+ and Tb3+ ions were investigated. The 1.48-μm emission due to the Tm3+ : ³H4→³F4 transition can be used to amplify the S-band (1460-1530-nm) signal light. With Tb3+ addition, the lifetime and emission intensity of the Tm3+ : ³F4 level decreased sharply via the Tm3+ : ³F4 → Tb3+ : 7 F0.12 energy transfer. Population densities of the ³F4 and ³H4 levels in Tm3+ calculated from rate equations clearly verified that population inversion in Tm3+ ions became possible with as little as 0.1 mol% of Tb3+ addition. [ABSTRACT FROM AUTHOR]

Glasses and glass-ceramics were prepared by melting municipal solid waste (MSW) incinerator fly ash and their corrosion properties were evaluated. Corrosion of both materials proceeded in two different steps. At the initial stage, the corrosion process is a diffusion-controlled process. After ∼10 h at the initial stage, weight losses increased linearly with time due to the total dissolution of glasses or glass-ceramics. Leaching of heavy metals from glasses and glass-ceramics were well within international environmental regulations. Corrosion proceeded uniformly in fly ash glass while Na2CaSiO4 crystalline phase was preferentially dissolved in the glass-ceramics. [Copyright &y& Elsevier]

Spectroscopic properties of 1.6 μm emission from Ho3+-doped sulfide glass were evaluated for their potential use as U-band fiber-optic amplifiers. Emission from the 5I5 → 5I7 transition showed a peak wavelength of 1670 nm and a full width at half maximum of ∼65 nm with a cross-section of ∼7.1 × 10−21 cm2. Ho3+ concentration in glass should be limited to 0.08 mol% due to energy transfers between Ho3+ ions which lead to a decrease in the 5I5 level lifetime. Co-doping of Tb3+ effectively decreased terminal 5I7 level lifetimes via the energy transfer of Ho3+:5I7 → Tb3+:7F0, 1, 2. [Copyright &y& Elsevier]

Emission characteristics and energy transfer in chalcohalide glasses doped with Tm3+ and Tb3+ were investigated and their potential as S-band fiber-optic amplifiers was evaluated. Upon the addition of CsBr into sulfide glass, intensity of the 1.48 μm emission (3H4 → 3F4 transition) from Tm3+ increased. At the same time, the lifetime of the 3H4 level increased to 1.2 ms, approximately eight times longer than the value obtained from sulfide glass. Quantum efficiency of the transition also increased to approximately 90%. Cross relaxation between the 3H4 and 3F4 levels was significant when Tm3+ ion concentration exceeded 0.2 mol%. Population density of the 3F4 level in Tm3+ decreased upon the addition of Tb3+ due to the Tm3+:3F4 → Tb3+:7F0,1,2 energy transfer. Population inversion became possible when Tb3+ concentration reached 0.11 mol%. [Copyright &y& Elsevier]

Emission properties associated with the fiber-optic amplification in Ge–Ga–S–CsBr glasses were investigated. The intensity of the 1.31 μm emission from Dy3+ (6F11/2 · 6H9/2 → 6H15/2) increased sharply when the appropriate concentrations of alkali halides were added, at the expense of the 1.75 μm emission intensity (6H11/2 → 6H15/2). The lifetimes of the 1.31 μm emission level also increased up to 1580 μs. A small amount of As was added to increase the resistivity against the recrystallization during re-heating. The optimum composition for practical usage was 0.7[Ge0.25As0.10S0.65]–0.15GaS3/2–0.15CsBr. Phonon side band showed that the several local phonon modes, with the frequencies around 100 cm−1, were coupled to 4f electrons of Eu3+. The nearest neighbors of Eu3+ ions are composed of halogen ions that are part of well-structured complex such as tetrahedral [GaS3/2Br]− subunit and/or Ga2Br6. [Copyright &y& Elsevier]

Addition of CsBr and KBr into Eu3+-doped Ge–Ga–S glasses resulted in persistent spectral hole burning with high quantum efficiency, whereas the addition of alkali chloride did not show any evidence for a hole formation process. The characterization of the phonon side band spectra revealed the site for Eu3+ ions located near the Ga–Br− or Ga–Cl− units. The presence of Br− ions near Eu3+ lowers the energy of the conduction band, thereby enabling the interaction between the 4f electrons and the resultant conduction band. The interaction made the photo-reduction of Eu3+ to Eu2+ possible. However, the higher coupling of phonon energy with Eu3+ together with the higher electronegativity of Cl− ion in CsCl-containing glass compared to its CsBr counterpart, hindered the photo-reduction of Eu3+ into Eu2+. [Copyright &y& Elsevier]

Cross relaxation among Tm3+ ions in Ge30Ga2As6S62 glass, where an ion excited to the 3H4 level transfers part of its energy to a nearby ion in the ground state 3H6 (3H4, 3H6→3F4, 3F4), was investigated in the temperature range of 20–300 K. The relative intensity ratio of the 1.48 μm emission to 1.84 μm increased with decreasing temperature. At the same time, the lifetime of the 3H4 level increased. Analysis of decay curves of the 1.48 μm emission suggested that cross relaxation was assisted by phonons of 390 cm−1 in frequency. These phonons are generated from the asymmetrical stretching vibration of GeS4 tetrahedra. Critical distance for cross relaxation decreased from 0.73 to 0.58 nm as the temperature decreased. [Copyright &y& Elsevier]

Spectroscopic properties and local structure of rare-earth ions in Ge–Ga–S glasses with the addition of alkali halides were investigated. The intensity of the 1.31-μm emission from Dy3+ (6F11/2·6H9/2 → 6H15/2) increased sharply when the appropriate amount of alkali halides was added, at the expense of the 1.75-μm emission intensity (6H11/2 →6H15/2). The lifetimes of the 1.31-μm emission level also increased as much as 35 times from 38 μs for Ge–Ga–S glass (0.1 at.% Dy3+) to 1320 μs for glass containing 10 mol% of CsBr. These enhancements occurred only when the ratio of MX(M = K,Cs and X = Br, I)/Ga was equal to or larger than unity. Phonon side band (PSB) showed that the several local phonon modes, with the frequencies around 100 cm–1, were coupled to 4f electrons of Eu3+. The nearest neighbors of Eu3+ ions are composed of halogen ions that are part of well-structured complex such as EuCl3, tetrahedral ⟦GaS3/2Cl〉– subunit and/or Ga2Cl6. A small amount of As was added to increase the resistivity against the recrystallization during re-heating. The best composition for practical usage was 0.7 ⟦Ge0.25As0.10S0.65〉–0.15 GaS3/2–0.15 CsBr. This glass also exhibited high resistance against the attack of liquid water and is therefore a potential material for efficient fiber-optic amplifiers. [Copyright &y& Elsevier]

Nucleation and crystallization kinetics concerning the conversion of a glass made from municipal solid waste (MSW) incinerator fly ash to glass-ceramics have been investigated. The maximum nucleation rate was found near 720 °C. Activation energies of crystallization were 468–293 kJ/mol and decreased with increasing powder particle size. Avrami exponents for crystallization were 1.5–2.0 which indicates that surface crystallization dominates the overall crystallization. Maximum crystallization can be achieved in a temperature range of 870–980 °C and this temperature increased as the particle size of the specimen increased. [Copyright &y& Elsevier]

Glasses were made using fly ash from municipal solid waste (MSW) incinerators with the addition of SiO2, MgO and TiO2. The glasses were then converted to glass-ceramics for further recycling to construction materials. The optimum heat-treatment schedule for the ceramitization of glasses was 720 °C for 90 min for nucleation and 870 °C for 10 h for crystal growth. Diopside (CaMgSi2O6) was formed as a major crystalline phase. The glass-ceramics showed good mechanical properties with a hardness of 6,730 MPa, fracture toughness of 1.86 Mpa m1/2 and bending strength of 127 MPa. Glasses and glass-ceramics with a composition of 20SiO2–5MgO–75fly ash–2TiO2 (all given in wt.%) showed an excellent resistance against leaching of heavy metal ions in water. The amount of heavy metal ions leached after 18 h at 23 °C was well below regulation with Cd2+ <0.04 ppm, Cr3+ <0.004 ppm, Cu2+ <0.03 ppm and Pb2+ <0.15 ppm, respectively. [Copyright &y& Elsevier]

Fluorescence and efficient persistent spectral hole burning of Eu3+ at 77 K were observed in chalcohalide glasses. The depth of the hole was approximately 30% after a burning process of 1 min with 50 mW power, and it was completely erased with Ar+ laser irradiation. The hole survived room temperature heat treatment and showed good thermal stability. The hole-burning mechanism was most probably the photo-reduction of Eu3+→Eu2+. Fluorescence from Eu3+ decreased with increasing temperature and disappeared at the temperature above ∼130 K. [Copyright &y& Elsevier]

Fly ash from municipal solid wastes (MSW) incinerators in Korea contains a large amount of toxic materials and requires pertinent treatments. However, since fly ash in Korea has a high chlorine concentration, it is difficult to apply cementation and chemical treatment techniques. In this study, we report the vitrification of fly ash along with the properties of the glasses and leaching characteristics of heavy metal ions.Fly ash can be vitrified by melting at 1500 °C for 30 min with the addition of >5 wt.% of SiO2. Glasses showed Vickers hardness of 4000–5000 MPa, bending strength of 60–90 MPa and indentation fracture toughness of ∼ 0.9 MPa m1/2. Glasses also showed the excellent resistance against leaching of heavy metal ions with Cd2+<0.04 ppm, Cr3+<0.02 ppm, Cu2+<0.04 ppm and Pb2+<0.2 ppm. These results indicate that the vitrification technique is effective for the stabilization and recycling of toxic incinerator fly ash. [Copyright &y& Elsevier]

The cardiotoxicity of various anticancer therapies, including radiotherapy, can lead to cardiovascular complications. These complications can range from damaging cardiac tissues within the irradiation field to increasing the long-term risks of developing heart failure, coronary artery disease, and myocardial infarction. We analyzed radiation-induced metabolites capable of mediating critical biological processes, such as inflammation, senescence, and apoptosis. Previously, by applying QTOF-MASS analysis to irradiated human fibroblasts, we identified that metabolite sets of lysophosphatidylcholine (LPC) were increased in these cells. In this study, radiation-induced LPC accumulation in human aortic endothelial cells (HAECs) increased reactive oxygen species (ROS) production and senescence-associated-beta-galactosidase staining, in addition to decreasing their tube-forming ability. Knockdown of lipoprotein-associated phospholipase A2 (Lp-PLA2) with small interfering RNA (siRNA) inhibited the increased LPC production induced by radiation, and reduced the radiation-induced cell damage produced by ROS and oxidized low-density lipoprotein (LDL). Lp-PLA2 depletion abolished the induction of proinflammatory factors, such as interleukin 1β, tumor necrosis factor-alpha, matrix metalloproteinase 2, and matrix metalloproteinase 9, as well as adhesion molecules, such as intercellular adhesion molecule 1 (ICAM-1) and E-selection. Likewise, we showed that Lp-PLA2 expression was upregulated in the vasculature of irradiated rat, resulting in increased LPC production and LDL oxidation. Our data demonstrate that radiation-induced LPC production is a potential risk factor for cardiotoxicity that is mediated by Lp-PLA2 activity, suggesting that LPC and Lp-PLA2 offer potential diagnostic and therapeutic approaches to cardiovascular damage during radiotherapy. [ABSTRACT FROM AUTHOR]

Precipitation of PbS quantum dots (QDs) in glasses was controlled by thermal diffusion of Ag+ ions from Ag paste at a temperature of 320°C. After subsequent heat treatment at 420–450°C, PbS QDs formed in the near-surface regions where the silver paste was applied. After the glasses were heat-treated at 440 or 450°C, PbS QDs were larger in Ag-affected surface regions than in Ag-free glasses. PbS QDs grew in Ag-affected regions when they were heat-treated at 420 or 430°C. Ag+ ions penetrated ~25μm from the glass surface after thermal diffusion of Ag+ ions and subsequent heat treatment at 430°C. Thermal diffusion of Ag+ ions from Ag paste is a viable method to control the precipitation and spatial distribution of PbS QDs in glasses. [ABSTRACT FROM AUTHOR]

Abstract: Electric-field assisted solid-state diffusion of Ag+ was used to control precipitation of PbS quantum dots (QDs) inside glasses. Precipitation of PbS QDs was confirmed by transmission electron microscopy images and photoluminescence (PL) spectra. PL bands moved to longer wavelengths as applied voltage increased under the same subsequent heat-treatment, and as heat-treatment temperature increased under the same voltage. PbS QDs can preferentially precipitate at low temperature and photo-luminesce at longer wavelengths in Ag+-affected regions than in unaffected regions. Ag nanoparticles were also formed inside affected regions after thermal treatment, and provided nucleation sites for PbS QDs. Precipitation of PbS QDs and their spatial distribution in glasses can be controlled by electric field-assisted Ag+ migration. [Copyright &y& Elsevier]

Various rare earth (RE) oxides such as Pr 2 O 3 , Dy 2 O 3 , Ho 2 O 3 , and Er 2 O 3 were introduced into Cd–S–Se quantum dot embedded glasses (QDEGs) to investigate their effect on the color conversion properties of the Cd–S–Se QDEGs. The absorption and emission peak wavelengths due to the excitonic transition of the Cd–S–Se QDs were modified by the introduction of RE oxides, implying their influence on QD formation. The photoluminescence of the various QDEGs RE oxides under 450 nm excitation were monitored and compared with the un-doped QDEGs. White LEDs (wLEDs) were also fabricated with the RE-doped QDEGs and their color conversion properties, such as quantum yield (QY), luminous efficacy, correlated color temperature (CCT) and color rendering index (CRI) were examined. Transmission electron microscope (TEM) revealed that the size and spatial distribution of the QDs were improved by the RE-oxides. Their effect on QD formation within the silicate glass was discussed using Raman spectroscopy. • Cd–S–Se quantum dot embedded glasses (QDEG) with various rare earth (RE) ions were fabricated. • RE ions reduced QD size and modified spectral properties of QDEGs. • RE ions improved size and spatial distribution of QDs within glass matrix. • White LED was successfully achieved with RE-doped QDEGs. [ABSTRACT FROM AUTHOR]

The preferential incorporation of Er3+ ions into the PbF2 nanocrystals during the ceraming process of oxyfluoride glass was analyzed using electron energy loss spectroscopy analysis. Concentrations of Er3+ ions were considerably higher in PbF2 nanocrystals compared to those in the glass matrix. Changes in lineshapes of absorption spectra from Er3+: 4 I15/2→4 I13/2 transition and lifetimes of the excited-state Er3+ (4 S3/2 level) ions also supported the incorporation of Er3+ ions into PbF2 nanocrystals. [ABSTRACT FROM AUTHOR]

Abstract: Mechanisms of the compositional dependence of blue emission from Nd3+/Tm3+ co-doped Ge–Ga–S–CsBr chalcohalide glasses were investigated. The blue upconversion emissions (centered at 475nm) due to the Tm3+: 1G4 → 3H6 transition decreased as the CsBr/Ga ratio in glasses while the other upconversion emissions from the Nd3+ ions increased. Changes in the local environment of rare-earth ions incurred by the CsBr addition significantly increased the excited state absorption within Nd3+ ions. This resulted in the decrease in the Nd3+ →Tm3+ energy transfer rates that led to the large decrease in blue upconversion emission. [Copyright &y& Elsevier]

Stromal cell-derived factor 1 (SDF-1) and its main receptor, CXC chemokine receptor 4 (CXCR4), play a critical role in endothelial cell function regulation during cardiogenesis, angiogenesis, and reendothelialization after injury. The expression of CXCR4 and SDF-1 in brain endothelial cells decreases due to ionizing radiation treatment and aging. SDF-1 protein treatment in the senescent and radiation-damaged cells reduced several senescence phenotypes, such as decreased cell proliferation, upregulated p53 and p21 expression, and increased senescence-associated beta-galactosidase (SA-β-gal) activity, through CXCR4-dependent signaling. By inhibiting extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription protein 3 (STAT3), we confirmed that activation of both is important in recovery by SDF-1-related mechanisms. A CXCR4 agonist, ATI2341, protected brain endothelial cells from radiation-induced damage. In irradiation-damaged tissue, ATI2341 treatment inhibited cell death in the villi of the small intestine and decreased SA-β-gal activity in arterial tissue. An ischemic injury experiment revealed no decrease in blood flow by irradiation in ATI2341-administrated mice. ATI2341 treatment specifically affected CXCR4 action in mouse brain vessels and partially restored normal cognitive ability in irradiated mice. These results demonstrate that SDF-1 and ATI2341 may offer potential therapeutic approaches to recover tissues damaged during chemotherapy or radiotherapy, particularly by protecting vascular endothelial cells. [ABSTRACT FROM AUTHOR]