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Isolated acid sites were selectively generated by postsynthesis modification of a borosilicate zeolite beta. To this end, samples were prepared with pairs of adjacent boron sites balanced by Ca2+ ions, whereas isolated boron in the zeolite framework was balanced by NH4+ ions. To avoid undesired boron leaching, these ion exchange reactions were carried out in methanol solution rather than in water. Trigonal boron forms near the NH4+ ions by decomposing the latter into NH3 (and a proton), and selective extraction of the trigonal boron is achieved by water treatment, whereas the tetrahedral boron near Ca2+ ions remains in the zeolite framework. The vacancies were refilled with aluminum by treatment with an aqueous Al(NO3)3 solution. Two Bronsted acid sites with 1H chemical shifts of 4.0 and 5.0 ppm exist in the dehydrated samples. 1H–27Al REAPDOR solid-state NMR measurements yield quantitative information on the local H–Al distances of isolated H–Al two-spin and H–Al–Al three-spin systems. The nearest H–Al d...

Aim Primary clear cell carcinoma of liver (PCCCL) is a specific and rare subtype of primary hepatocellular carcinoma (HCC). We performed a retrospective study with long-term follow-up to investigate predictive factors and prognosis of intrahepatic recurrences of PCCCL after radical resection. Methods We retrospectively analyzed records of 38 patients with PCCCL who were diagnosed at Peking Union Medical College Hospital between January 1989 and September 2010, with a long-term follow up to January 2015, to determine their clinical characteristics and postoperative survival. The data were compared with 400 patients received radical hepatectomy for common type hepatocellular carcinoma (CHCC) during the study period. Results PCCCL tumors were smaller than those of CHCC (P < 0.001) and the incidence of vascular invasion of tumors in PCCCL group was significantly lower than that in CHCC (P = 0.029). The 1-, 3-, and 5-year overall survival (OS) for PCCCL patients were 94.6%, 67.3%, and 58.5%, respectively; 1-, 3-, and 5-year disease-free survival (DFS) were 89.2%, 54.1%, and 48.6%, respectively. Both OS and DFS were significantly better for PCCCL patients than for CHCC (P = 0.039 and 0.044). Cox modeling showed high Edmondson grade to be the only independent predictive factor for survival of PCCCL patients, which were different from those of CHCC. Conclusions PCCCL is a less malignant subtype of HCC than CHCC, patients with PCCCL likely have later intrahepatic recurrences and a better prognosis. Edmondson grade predicts survival of patients with PCCCL after curative resection; those with higher Edmondson grades may require more careful follow-up and aggressive post-hepatectomy therapy.

A series of glasses with the compositions of 10NaF-(90-x) NaPO3-xYF3 (x = 5, 10, 15 and 20 mol%) were prepared via the conventional melt-quenching method. The structures of these glasses were characterized by multiple advanced solid-state nuclear magnetic resonance (SSNMR) techniques. Multiple phosphorus species QmnY were resolved at atomic level. Here, the value m and n denote the number of P–O–P bonds and the number of Y3+ ion bounding to phosphorus oxygen tetrahedron, respectively, which were identified by two dimensional (2D) J-resolved spectroscopy. 19F MAS spectra, 19F↔23Na and 19F↔31P rotational echo double resonance (REDOR) prove that F−ions are involved into the glass networks through Y-F•••Na and P-F•••Na linkages. The 31P {19F} J-coupling based heteronuclear multiple quantum coherence (J-HMQC) spectrum proves that F− ions selectively connect with Q1 species. F− ions show significant preference to connecting with Y3+ over P5+.

The mixed alkaline earth effect (MAEE) is important for several families of industrial borosilicate and aluminosilicate glasses, including glasses used in pharmaceutical packaging and as substrates for flat panel displays. Despite the technological importance of the mixed alkaline earth effect, the physical origin of this phenomenon is not well understood, and there is currently no model to offer quantitative prediction of the effect. In this work, the MAEE is studied both experimentally and through modeling in a series of boroaluminosilicate glasses with systematic substitution of CaO with MgO. The network structure is characterized by magic angle spinning nuclear magnetic resonance (MAS NMR) analyses of 27Al, 11B, 29Si, and 23Na. Molecular dynamics (MD) simulations are conducted to simulate the glass structures and calculate the evolution of the bond angle distributions with composition. Based on the structural data, a topological constraint model is proposed to capture the MAEE on glass transition temperature (Tg), liquid fragility index (m), and Young's modulus (E) of the glasses. Results of the topological constraint model are in good quantitative agreement with experimental data. The success of the constraint model confirms that the mixed alkaline earth effect is the result of a shift in angle around oxygen in the cation-oxygen-cation bond in the glass network. This is related to the constraint strength that ultimately governs the nonlinear property variation.

Yb

Sodium phosphosilicate glasses with high phosphate contents represent an unusual case in glass science as they are known to contain large amounts of six-coordinated silicon species (SiO6/2 units, Si(6)). Although the network connectivity of these units has been previously investigated, the overall structural organization of this system at the medium-range order level is still incompletely understood. In the present study, this issue is addressed by using a comprehensive suite of homo- and heteronuclear dipolar recoupling studies involving the nuclear isotopes 23Na, 29Si, and 31P on isotopically enriched glasses in the systems xSiO2–(1 – x)(0.45Na2O–0.55P2O5) (x = 0.0, 0.1, and 0.2) and 0.2SiO2–0.2Na2O–0.6P2O5. Four- and six-fold coordinated silicon species (Si(4) and Si(6)) coexist in these glasses. Invariably, Si(6) selectively connects with phosphate species, which are exclusively of the P(3) type, whereas the Si(4) species are coordinated to both P(2) and P(3) units. 29Si ↔ 23Na and 31P ↔ 23Na rotation...

Two series of silica glasses [(95.9−x)SiO2–4Al2O3–xP2O5–0.1Yb2O3 (in mol%, x=0–10) and (92−y) SiO2–4Al2O3–4P2O5–yYb2O3 (in mol%, y=0–0.2)] were prepared by sol–gel method combined with high-temperature sintering. The relationship between the glass structure and spectroscopic properties is investigated. Significant alterations in density, refractive index, absorption and emission cross sections, fluorescence lifetime, and scalar crystal field NJ are observed at a molar ratio of P5+/Al3+=1 due to the transformation of P5+ structure type from AlPO4-like to PO4 units. This structural change is clearly observed in Raman spectra. In addition, NMR experimental results suggest that Yb3+ is mainly located in AlPO4-like but not SiO4 units at a molar ratio of P5+/Al3+=1, and also Raman spectra reveals the presence of P=O linkage in samples with molar ratio of P5+/Al3+>1. This further demonstrates that it is due to the formation of P=O site but not the simple addition of P2O5 in Yb3+/Al3+/P5+ co-doped silica glass to significantly decrease the absorption and emission cross sections of Yb3+. It reflects in the change of Yb3+ Stark splitting, and is revealed by the decline of Yb3+ asymmetry degree.

A new pulse sequence entitled DQ-DRENAR (Double-Quantum based Dipolar Recoupling Effects Nuclear Alignment Reduction) was recently described for the quantitative measurement of magnetic dipole-dipole interactions in homonuclear spin-1/2 systems involving multiple nuclei. As described in the present manuscript, the efficiency and performance of this sequence can be significantly improved, if the measurement is done in the constant-time mode. We describe both the theoretical analysis of this method and its experimental validation of a number of crystalline model compounds, considering both symmetry-based and back-to-back (BABA) DQ-coherence excitation schemes. Based on the combination of theoretical analysis and experimental results we discuss the effect of experimental parameters such as the chemical shift anisotropy (CSA), the spinning rate, and the radio frequency field inhomogeneity upon its performance. Our results indicate that constant-time (CT-) DRENAR is a method of high efficiency and accuracy for compounds with multiple homonuclear spin systems with particular promise for the analysis of stronger-coupled and short T2 spin systems.

A new solid state NMR technique entitled DQ-DRENAR (Double-Quantum based Dipolar Recoupling Effects Nuclear Alignment Reduction) has been recently described for measuring homonuclear dipole-dipole interactions in multi-spin-1/2 systems under magic-angle spinning conditions. As in rotational echo double resonance (REDOR), the homonuclear dipole-dipole coupling constant can be extracted from a plot of a normalized difference signal (S0-S')/S0 versus dipolar mixing time, where S is the signal amplitude with the DQ-Hamiltonian present, and S0 is the signal amplitude in the absence of the DQ-Hamiltonian, which is used for normalization. Within the range of (S0-S)/S0≤0.3-0.5 such "homonuclear REDOR curves" can be approximated by simple parabolae, yielding effective squared dipole-dipole coupling constants ∑bjk(2) summed over all the pairwise interactions present. The effect of glassy disorder has been studied by simulations, replacing singular-valued internuclear distances by Gaussian distance distributions with the same central value. This situation results in a systematic over-estimation effect, which tends to compensate the implicit under-estimation effect caused by the parabolic fitting approach. The present contribution describes applications to a number of phosphate-based glasses and glass ceramics. The method turns out to be well suited for the differentiation of the various Q((n)) phosphate species, for characterizing the spatial distribution of isolated orthophosphate ions and for the detection of incipient nano-segregation and/or phase separation effects in glass ceramics.

We investigated moderate-temperature oxygen diffusion mechanisms in Sr2ScGaO5 with Brownmillerite structure type. From oxygen isotope 18O−16O exchange experiments we determined that oxygen mobility sets in above 550 °C. Temperature-dependent neutron and X-ray (synchrotron) diffraction experiments allowed us to correlate the oxygen mobility with a subtle phase transition of the orthorhombic room-temperature structure with I2mb space group toward Imma, going along with a disorder of the (GaO4)∞-tetrahedral chains. From lattice dynamical simulations we could clearly evidence that dynamic switching of the (GaO4)∞-tetrahedral chains from its R to L configuration sets in at 600 °C, thus correlating oxygen diffusion with the dynamic disorder. Oxygen ion diffusion pathways are thus constrained along the onedimensional oxygen vacancy channels, which is a different diffusion mechanism compared to that of the isostructural CaFeO2.5, where diffusion of the apical oxygen atoms into the vacant lattice sites are equally involved in the diffusion pathway. The proposed ordered room-temperature structure in I2mb is strongly supported by 17O, 45Sc, and 71Ga NMR measurements, which indicate the presence of crystallographically unique sites and the absence of local disordering effects below the phase transition. The electric field gradient tensor components measured at the nuclear sites are found to be in excellent agreement with calculated values using the WIEN2k program. The oxygen site assignment has been independently confirmed by 17O{45Sc} transfer of adiabatic populations double-resonance experiments.

Although a fairly large number of binary group 15/16 element cations have been reported, no example involving phosphorus in combination with a group 16 element has been synthesized and characterized to date. In this contribution is reported the synthesis and structural characterization of the first example of such a cation, namely a nortricyclane-type [P3Se4](+). This cation has been independently discovered by three groups through three different synthetic routes, as described herein. The molecular and electronic structure of the [P3Se4](+) cage and its crystal properties in the solid state have been characterized comprehensively by using X-ray diffraction, Raman, and nuclear magnetic resonance spectroscopies, as well as quantum chemical calculations.

International audience; To investigate clusters of Yb ions and the effectiveness of lanthanum co-doping in dispersing and isolating Yb ions in silica glass, Yb-doped high-silica lanthanum aluminosilicate (LAS) glass with compositions Yb2O3 Al2O3 La2O3 SiO2 was prepared by the sol-gel method combined with high temperature sintering. The glass structure and spectroscopic properties of Yb-doped high-silica LAS glass were studied in detail to explore the mechanism of cluster dissolution. 27Al and 29Si solid-state nuclear magnetic resonance (SSNMR) spectra were introduced to study the spatial distribution of the Yb ions in the glass. The spinning sideband patterns of the 27Al and 29Si NMR spectra showed that part of the Yb3+ ions in the vicinity of aluminium atoms transferred to Si ions with increasing La2O3 concentration. The results of two-dimensional hyperfine sublevel correlation (2D-HYSCORE) electron paramagnetic resonance (EPR) spectroscopy led to the conclusion that the vicinity of Yb3+ ions are mostly aluminum atoms for glass doped with Al and aluminum and silicon atoms for glass co-doped with Al and La. It was also found that Yb clusters exist in the form of YbOYb bonds in high-concentration Yb-doped silica glass and that co-doping with La can replace these bonds with YbOLa linkages to reduce the number of Yb3+ pairs. The fluorescence intensity and fluorescence lifetime of Yb increase steadily with increasing La2O3 concentration, which also indicates that the addition of La in silica glass can dissolve the Yb clusters. The results show that co-doping high-silica LAS glasses with La3+ ions is an ideal way to increase Yb solubility and decrease clustering.

We present a combined theoretical and experimental analysis of the carbon–carbon bond character in two prototypical zirconocene complexes. The two cyclic seven-membered ring zirconium compounds 2a and 2b differ by the substitution of a tert-butyl by a trimethylsilyl group. Due to the coordination of the π-system to the metal atom, a formally forbidden (η2-allenyl)/enamido-Zr to (η2-alkyne)/κN-imine-Zr complex isomerization is feasible. State-of-the-art dispersion-corrected density functional theory (DFT-D3) is used in both the solid and condensed phase to examine and quantify the experimental structures (X-ray diffraction) and 13C NMR magnetic shielding. The complementary investigations demonstrate the importance of nonlocal London dispersion interactions. Both X-ray structures agree excellently with the results of the solid-state DFT-D3 calculations. Interestingly, 2b exhibits a mixed allene–alkyne form in the solid state, while its gas phase structure has a strong allene character. The substitution lead...

The vicinal frustrated Lewis pair (FLP) mes2P-CH2CH2-B(C6F5)2 (3) reacts with phenyl(trimethylsilyl)acetylene by 1,1-carboboration to give the extended C3-bridged FLP 6 featuring a substituted vinylborane subunit. The FLP 6 actively cleaves dihydrogen. The FLP 3 also undergoes a 1,1-carboboration reaction with diphenylphosphino(trimethylsilyl)acetylene to give the P/B/P FLP 11 that features a central unsaturated four-membered heterocyclic P/B FLP and a pendant CH2CH2-Pmes2 functional group. Compound 11 reacts with nitric oxide (NO) by oxidation of the pendant Pmes2 unit to the P(O)mes2 phosphine oxide and N,N-addition of the P/B FLP unit to NO to yield the persistent P/B/PO FLPNO aminoxyl radical 14. This reaction is initiated by P(O)mes2 formation and opening of the central Ph2P···B(C6F5)2 linkage triggered by the pendant CH2CH2-P(O)mes2 group.

No-bond 31P–31P indirect dipolar couplings, which arise from the transmission of nuclear spin polarization through interaction of proximal nonbonded electron pairs have been investigated in the solid state for a series of closely related substituted P,P-[3]ferrocenophanes and model systems. Through variation and combination of ligands (phenyl, cyclohexyl, isopropyl) at the two phosphorus sites, the P···P distances in these compounds can be varied from 3.49 to 4.06 A. Thus, the distance dependence of the indirect no-bond coupling constant Jnb can be studied in a series of closely related compounds. One- and two-dimensional solid-state NMR experiments serve to establish the character of these couplings and to measure the isotropic coupling constants Jiso, which were found to range between 12 and 250 Hz. To develop an understanding of the magnitude of Jnb in terms of molecular structure, their dependences on intramolecular internuclear distances and relative orbital orientations is discussed by DFT-calculati...

The synthesis of the new vicinal frustrated Lewis pair 5 containing (C6F5)2P-Lewis base and (C6F5)BH-Lewis acid functionality is described. It forms a unique cyclotrimer (5)3 which was structurally characterized by X-ray crystallography and high-resolution solid-state NMR spectroscopy. The relevant NMR Hamiltonian parameters ((11)B and (31)P chemical shielding tensors, (11)B quadrupolar coupling tensors, and (31)P-(11)B spin-spin coupling constants) indicate significant intramolecular covalent BP interactions, consistent with results from density functional theory (DFT) calculations. In addition, the (11)B/(31)P and (31)P/(31)P three-spin geometries are accurately reproduced by suitable high-resolution hetero- and homonuclear dipolar NMR experiments. As predicted from the bonding character portrayed by the solid-state NMR results, the cyclotrimer (5)3 possesses only moderate catalytic activity. However, it undergoes an addition reaction with pyridine and hydroboration reactions with benzaldehyde and tert-butylacetylene. The products of the hydroboration reactions form stable adducts with pyridine.

Homogeneous 89.9SiO2-4Al2O3-6P2O5–0.1Yb2O3/Eu2O3 glasses were fabricated via a sol−gel method and sintered under vacuum at high temperature, and subsequently they were annealed at 850 °C for 15 and 75 h. Effect of thermal annealing time on structures and properties of glasses was systematically investigated. Solid state nuclear magnetic resonance (SSNMR) and Raman scattering spectra were employed to characterize the network structures. Pulse electron paramagnetic resonance (EPR) techniques and the emission and excitation spectra of Eu3+ ions were used to study the local environment of Yb3+ ions. SSNMR and Raman results indicate that AlPO4 units increase at the expense of AlV, AlVI and P(3) groups after annealing. The glass network structures have a significant influence on density and refractive index. EPR and Eu3+ spectra indicate an increase in Al around Yb3+ ions and a reduction in the asymmetry degree of Yb3+ ligands. A correlation between structures and properties of glasses is developed.

The structure of roller-quenched fast ion conductive glasses (FICs) (Ag3PO4)x(AgI)1–x (0.15 ≤ x ≤ 0.50) is investigated by 109Ag and 31P solid-state NMR spectroscopies. Monotonic linear dependences of 109Ag and 31P chemical shifts on x are consistent with a statistical distribution of the phosphate and iodide anions. This conclusion is quantitatively confirmed by a new 31P homonuclear magnetic dipolar recoupling method, termed double-quantum-based dipolar recoupling effects nuclear alignment reduction (DQ-DRENAR), which numerically proves a random spatial distribution of the phosphate anions. Altogether these results give the final answer to a long-standing debate on the structure of silver in AgI-based (FIC) glasses, proving the absence of previously postulated silver iodide cluster domains.

We present a novel “Top-down” strategy to design the long phosphorescent phosphors in the second biological transparency window via energy transfer. Inherence in this approach to material design involves an ingenious engineering for hybridizing the coordination networks of hosts, tailoring the topochemical configuration of dopants and bridging a cascaded tunnel for transferring the persistent energy from traps, to sensitizers and then to acceptors. Another significance of this endeavour is to highlight a rational scheme for functionally important hosts and dopants, Cr/Nd co-doped Zn1−xCaxGa2O4 solid solutions. Such solid-solution is employed as an optimized host to take advantage of its characteristic trap site level to establish an electron reservoir and network parameters for the precipitation of activators Nd3+ and Cr3+. The results reveal that the strategy employed here has the great potential, as well as opens new opportunities for future new-wavelength, NIR phosphorescent phosphors fabrication with many potential multifunctional bio-imaging applications.

The local structure of glassy NaPS 3 and AgPS 3 was analyzed based on quantitative 31 P MAS-NMR spectroscopy. The glasses contain some oxide impurities, which could be quantified from the NMR spectral analysis. Four discrete resonances are observed in both glasses, which were assigned to four distinct types of phosphate groups P ( n ) , where n is the number of P–S–P bridges(i.e., P (0) , P (1) , P (2) , and P (3) units, respectively) with the help of 2D homonuclear J-resolved and INADEQUATE methods. Based on the results obtained, the interpretations of previous spectra obtained at low spinning speeds on lithium and silver thiophosphate glasses ( Chem. Mater. 2 ( 1990), 273, and J. Am. Chem. Soc. 114 (1992), 5775 ) need to be revised. Contrary to the situation in alkali phosphate glasses, the corresponding sulfide analogs are characterized by a wide P ( n ) species distribution close to that predicted by a statistical charge distribution. INADEQUATE experiments fail to detect P ( n ) −P ( n −1) connectivities, suggesting that the structure of these glasses is rather inhomogeneous, possibly featuring the different P ( n ) species in segregated domains.

A series of heavy metal oxide (HMO) glasses with composition 26.66B2O3-16GeO2-4 Bi2O3-(53.33-x)PbO-xPbF2 (0 ≤ x ≤ 40) were prepared and characterized with respect to their bulk (glass transition and crystallization temperatures, densities, molar volumes) and spectroscopic properties. Homogeneous glasses are formed up to x = 30, while crystallization of β-PbF2 takes place at higher contents. Substitution of PbO by PbF2 shifts the optical band gap toward higher energies, thereby extending the UV transmission window significantly toward higher frequencies. Raman and infrared absorption spectra can be interpreted in conjunction with published reference data. Using 11B and 19F high-resolution solid state NMR as well as 11B/19F double resonance methodologies, we develop a quantitative structural description of this material. The fraction of four-coordinate boron is found to be moderately higher compared to that in glasses with the same PbO/B2O3 ratios, suggesting some participation of PbF2 in the network transf...

Transparent AlPO4 mesoporous glasses codoped with different amounts, as well as different molar ratios, of Rhodamine 6G (Rh6G) and Coumarin 102 (Cou102) were fabricated by a dipping method. Solidification of dyes in mesoporous AlPO4 glasses was probed by 27Al and 31P solid state NMR techniques. The interaction of dyes with the glassy AlPO4 network has been characterized by a new six-coordinated aluminum species (Al(6)) environment in 27Al MAS spectra, combined with advanced solid state NMR techniques probing 27Al−1H and 27Al−31P internuclear dipole couplings. Optical excitation and simultaneous dual-wavelength emission spectra of both series of samples show significant dependences on the Rh6G and Cou102 concentration and Cou102/Rh6G molar ratio. Efficient simultaneous dual-wavelength emission was observed at low dye concentration ( 10−3 M), quenching of the fluorescence of Cou102 happened, but the fluorescence intensity was dependent on the Cou102/Rh6G molar ratio.

Homogeneous monolith of AlPO4 gel doped with Rhodamine 6G (Rh6G) in different dye concentration is prepared by one step process with sol–gel method using the precursors Al(lact)3 and H3PO4. The optical properties of AlPO4 gel doped with Rh6G have been characterized by UV–vis absorption spectra and fluorescence spectra. Rh6G molecular J-dimers and H-dimers even multimers are analyzed by excitation spectra based on Exciton theory. The structure of AlPO4 gel doped with Rh6G is investigated by 27Al and 31P Magic Angle Solid Nuclear Magnetic Resonance (MAS NMR), 27Al {31P} Rotational Echo Double Resonance (REDOR) NMR and 27Al Triple Quantum Magic Angle Spinning (TQ-MAS) NMR. Based on the results of optical spectra and the structural analysis by NMR techniques, The AlPO4 gel doped with Rh6G dye with molar ratio of Rh6G/Al(lact)3 of 1 × 10−4 displays excellent optical properties.

Luminescences from bismuth-doped lime silicate glasses were investigated. Luminescences centered at about 400, 650, and 1300 nm were observed, excited at 280, 532 and 808 nm, respectively. These three luminescence bands arise from three different kinds of bismuth ions in the glasses. The visible luminescences centered at 400 and 650 nm arise from Bi 3+ , and Bi 2+ , respectively. The infrared luminescences cover the wavelength range from 1000 to 1600 nm when exited by an 808 nm laser diode. The full width at half maximum (FWHM) of the infrared luminescences is more than 205 nm. The intensity of the infrared luminescence decreases with the increment in CaO content. We suggest that the infrared luminescences might arise from Bi + . Such broadband luminescences indicate that the glasses may be potential candidate material for

Transparent Ni2+-doped MgO–Al2O3–SiO2 glass ceramics without and with Ga2O3 were synthetized. The precipitation of spinel nanocrystals, which was identified as solid solutions in the glass ceramics, could be favored by Ga2O3 addition and their sizes were about 7.6 nm in diameter. The luminescent intensity of the Ni2+-doped glass ceramics was largely enhanced by Ga2O3 addition which could mainly be caused by increasing of Ni2+ in the octahedral sites and the reduction of the mean frequency of phonon density of states in the spinel nanocrystals of solid solutions. The full width at half maximum (FWHM) of emissions for the glass ceramics with different Ga2O3 content was all more than 200 nm. The emission lifetime increased with the Ga2O3 content and the longest lifetime is about 250 μs. The Ni2+-doped transparent glass ceramics with Ga2O3 addition have potential application as broadband optical amplifier and laser materials.

Broadband infrared luminescence is observed in various Bi-doped oxide glasses prepared by conventional melting-quenching technique. The absorption spectrum of the Bi-doped germanium oxide glass consists of five broad peaks at below 370, 500, 700, 800 and 1000 nm. The fluorescence spectrum exhibits a broad peak at about 1300 nm with full width at half maximum (FWHM) of more than 300 nm when excited by an 808 nm laser diode. The fluorescence lifetime at room temperature decreases with increasing Bi2O3 concentration. Influence of the glass composition and melting atmosphere on the fluorescence lifetime and luminescent intensity is investigated. The mechanism of the broadband infrared luminescence is suggested. The product of stimulated emission cross-section and lifetime of the Bi-doped aluminophosphate glass is about 5.0 X 10(-24) cm(2) s. The glasses might be promising for applications in broadband optical fiber amplifiers and tunable lasers. (c) 2007 Elsevier B.V. All rights reserved.

Yb-doped and Yb–Al-codoped high silica glasses have been prepared by sintering nanoporous glasses. The absorption, fluorescent spectra and fluorescent lifetimes have been measured and the emission cross-section and minimum pump intensities were calculated. Codoping aluminum ions enhanced the fluorescence intensity of Yb-doped high silica glass obviously. The emission cross-sections of Yb-doped and Yb–Al-codoped high silica glasses were 0.65 and 0.82 pm2, respectively. The results show that Yb–Al-codoped high silica glass has better spectroscopic properties for a laser material. The study of high silica glass doped with ytterbium is helpful for its application in Yb laser systems, especially for high-power and high-repetition lasers.

Broadband near-infrared (IR) luminescence in transparent alkali gallium silicate glass-ceramics containing Ni2+-doped β-Ga2O3 nanocrystals was observed. This broadband emission could be attributed to the 3T2g (3F) → 3A2g (3F) transition of octahedral Ni2+ ions in glass-ceramics. The full width at half-maximum (FWHM) of the near-IR luminescence and fluorescent lifetime of the glass-ceramic doped with 0.10 mol% NiO were 260 nm and ∼1220 μs, respectively. It is expected that transparent Ni2+-doped β-Ga2O3 glass-ceramics with this broad near-IR emission and long fluorescent lifetime have potential applications as super-broadband optical amplification media.

In this paper, we present the broadband optical amplification in bismuth-doped germanate glass, at the second telecommunication window when excited with 808 nm and 980 nm laser diodes, respectively. The amplification range is from 1272 nm to 1348 nm wavelength, which is within the O-band of silica fiber communication. This bismuth-doped glass can be used as ultra broadband amplification material for wavelength-division-multiplexing (WDM) at the second telecommunication window.

Infrared (IR) luminescence covering 1.1 to ∼1.6 μm wavelength region was observed from bismuth-doped barium silicate glasses, excited by a laser diode at 808 nm wavelength region, at room temperature. The peak of the IR luminescence appears at 1325 nm. A full width half-maximum (FWHM) and the lifetime of the fluorescence is more than 200 nm and 400 μs, respectively. The fluorescence intensity increases with Al2O3 content, but decreases with BaO content. We suggest that the IR luminescence should be ascribed to the low valence state of bismuth Bi2+ or Bi+, and Al3+ ions play an indirect dispersing role for the infrared luminescent centers.

We report on ultrabroad infrared (IR) luminescences covering the 1000–1700-nm wavelength region, from Bi-doped 75GeO2–20RO–5Al2O3–1Bi2O3(R = Sr, Ca, and Mg) glasses. The full width at half-maximum of the IR luminescences excited at 980 nm increases (315 → 440 → 510 nm) with the change of alkaline earth metal (Mg2+→ Ca2+→ Sr2+). The fluorescence lifetime of the glass samples is 1725, 157, and 264 μs when R is Sr, Ca, and Mg, respectively. These materials may be promising candidates for broad-band fiber amplifiers and tunable laser resources.

We report transparent Ni 2+ -doped ZnO–Al 2 O 3 –SiO 2 system glass-ceramics with broadband infrared luminescence. After heat-treatment, ZnAl 2 O 4 crystallite was precipitated in the glasses, and its average size increased with increasing heat-treatment temperature. No infrared emission was detected in the as-prepared glass samples, while broadband infrared luminescence centered at 1310 nm with full width at half maximum (FWHM) of about 300 nm was observed from the glass-ceramics. The peak position of the infrared luminescence showed a blue-shift with increasing heat-treatment temperature, but a red-shift with an increase in NiO concentration. The mechanisms of the observed phenomena were discussed. These glass-ceramics are promising as materials for super broadband optical amplifier and tunable laser.

We report ultrabroad infrared luminescence from Bi-doped aluminogermanate glasses. The infrared luminescence almost covers the whole low loss wavelength region (1200–1650 nm) of silica glass fiber when excited by a diode laser at 980 nm. The full width at half maximum (FWHM) of the luminescence is 510 nm. The luminescence peak can be divided into three Gaussian peaks, and the fluorescence lifetime of the three emissions are 297 μs, 470 μs and 1725 μs, respectively. These fluorescence properties indicate that the glasses are promising material for broadband optical amplifiers.

A new pulse sequence entitled DQ-DRENAR, (Double-Quantum based Dipolar Recoupling Effects Nuclear Alignment Reduction) was recently described for the quantitative measurement of magnetic dipole-dipole interactions in homonuclear spin-1/2 systems involving multiple nuclei. The double quantum coherences were created via a windowless symmetry-based pulse sequence (POST-C7). The present contribution evaluates the performance of the "Back-to-Back" excitation pulse scheme BABA-xy16 in such DRENAR experiments. Using SIMPSON simulations, special attention is given to finite pulse length effects, dipolar truncation, and chemical shift anisotropy interference. Experimental results on model compounds demonstrate good stability up to long mixing times (>10 ms) as well as high accuracy. As its dipolar coupling efficiency is relatively high (the dipolar coupling scaling factor is 4.24 times as high as that of POST-C7), DQ-DRENAR-BABA-xy16 is most appropriate for the measurement of relatively weak dipolar coupling strengths (

To investigate the protective effect of magnesium isoglycyrrhizinate (MgIG) on excessive hepatectomy animal model and its possible mechanism.We used the standard 90% hepatectomy model in Sprague-Dawley rats developed using the modified Emond's method, in which the left, middle, right upper, and right lower lobes of the liver were removed. Rats with 90% liver resection were divided into three groups, and were injected intraperitoneally with 3 mL saline (control group), 30 mg/kg (low-dose group) and 60 mg/kg (high-dose group) of MgIG, respectively. Animals were sacrificed at various time points and blood was drawn from the vena cava. Biochemical tests were performed with an automatic biochemical analyzer for the following items: serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutamyl endopeptidase, total bilirubin (TBil), direct bilirubin (DBil), total protein, albumin, blood glucose (Glu), hyper-sensitivity C-reactive protein, prothrombin time (PT), and thrombin time (TT). Postoperative survival time was observed hourly until death. Hepatocyte regeneration was analyzed by immunohistochemistry. Serum inflammatory cytokines (IL-1, IL-6, IL-10, and iNOS) was analyzed by ELISA. STAT3 protein and mRNA were analyzed by Western blot and quantitative reverse-transcription PCR, respectively.The high-dose group demonstrated a significantly prolonged survival time, compared with both the control and the low-dose groups (22.0 ± 4.7 h vs 8.9 ± 2.0 vs 10.3 ± 3.3 h, P = 0.018). There were significant differences among the groups in ALT, Glu and PT levels starting from 6 h after surgery. The ALT levels were significantly lower in the MgIG treated groups than in the control group. Both Glu and PT levels were significantly higher in the MgIG treated groups than in the control group. At 12 h, ALT, AST, TBil, DBil and TT levels showed significant differences between the MgIG treated groups and the control group. No significant differences in hepatocyte regeneration were found. Compared to the control group, the high-dose group showed a significantly increase in serum inflammatory cytokines IL-1 and IL-10, and a decrease in IL-6. Both STAT3 protein and mRNA levels were significantly lower in the MgIG treated groups than in the control group at 6 h, 12 h, and 18 h after surgery.High-dose MgIG can extend survival time in rats after excessive hepatectomy. This hepatoprotective effect is mediated by inhibiting the inflammatory response through inhibition of the STAT3 pathway.

An R 2 O-B 2 O 3 -SiO 2 (R = Li, Na, K) polarizing glass containing Ag nanorods is prepared by thermal elongation-reduction technology. The transverse and longitudinal plasmon absorption peaks of the embedded Ag nanorods are near 460 and 720 nm, respectively. When the polarization of the laser is parallel to the long axis of the Ag nanorods, the nonlinear absorption coefficient β=0.82 cm GW -1 and the nonlinear refractive index n 2 = -1.5 x10 -4 cm 2 GW -1 . When the polarization of light is perpendicular to the long axis of the Ag nanorods β= 0.12 cm GW -1 and n 2 = -7.2 x 10 -5 cm 2 GW -1 and the appropriate one- and two-photon figures of merit (FOM), W= 1.6 and T=0.16, respectively, are obtained, which satisfies the demand, W> 1 and T

We report on the effect of various alkaline-earth metal oxides on the broadband infrared luminescence covering 1000‐1600 nm wavelength region from bismuth-doped silicate glasses. The full width at half maximum (FWHM) of the infrared luminescence and the fluorescent lifetime is more than 200 nm and 400 µs, respectively. The fluorescent intensity decreases with increasing basicity of host glasses. Besides the broadband infrared luminescence, luminescence centered at 640 nm was also observed, which should be ascribed to Bi 2+ rather than to the familiar Bi 3+ . We suggest that the infrared luminescence should be assigned to the X2 2 3/2 ! X1 2 1/2 transition of BiO molecules dispersed in the host

International audience; Output power scaling of single mode large mode area (LMA) photonic crystal fiber (PCF) amplifiers urgently requires the low refractive index of Yb 3+-doped silica glasses whilst maintaining high optical homogeneity. In this paper, we report on a promising alternative Yb 3+ /Al 3+ /F-/P 5+-co-doped silica core-glass (YAFP), which is prepared by modified sol-gel method developed by our group and highly suitable for fabricating high power LMA PCF amplifiers. By controlling the doping combinations of Al 3+ /F-/P 5+ in Yb 3+doped silica glass,it not only ensures low refractive index (RI) but also maintains the excellent optical homogeneity and spectroscopic properties of Yb 3+. The spectroscopic properties of Yb 3+ ions have not deteriorated by the co-doping of Fand P 5+ in YAFP glass compared with that of Yb 3+ /Al 3+ co-doped silica glass. A large-size (⌀5 mm × 90 mm) YAFP silica-core glass rod with low average RI difference of 2.6 × 10 −4 (with respect to pure silica glass), and low radial and axial RI fluctuations of ~2 × 10 −4 , was prepared. A LMA PCF with 50 µm core diameter was obtained by stack-capillary-draw techniques using YAFP core glass. Its core NA is 0.027. An average amplified power of 97 W peaking at 1030 nm and light-light efficiency of 54% are achieved from a 6.5 m long PCF in the pulse amplification laser experiment. Meanwhile, quasi-single-mode transmission is obtained with laser beam quality factor M 2 of 1.4.

AIM: To analyze the expression profiles of long non-coding RNAs (lncRNAs) in hepatocellular carcinoma. METHODS: Hepatocellular carcinoma (HCC) tissues and matched adjacent non-tumor (NT) liver tissues were collected from 29 patients with HCC, immediately after liver resection, between March 2011 and July 2013. The diagnosis of HCC was made based on histological examination. Differentially expressed lncRNAs between HCC and NT tissues were revealed through microarray-based lncRNAs expression profiling. Further, quantification of selected lncRNAs was performed using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: Six hundred and fifty-nine lncRNAs were differentially expressed between HCC and NT tissues, of which five [TCONS_00018278, {"type":"entrez-nucleotide","attrs":{"text":"AK093543","term_id":"21752443","term_text":"AK093543"}}AK093543, {"type":"entrez-nucleotide","attrs":{"text":"D16366","term_id":"303612","term_text":"D16366"}}D16366, ENST00000501583, {"type":"entrez-nucleotide","attrs":{"text":"NR_002819","term_id":"764020144","term_text":"NR_002819"}}NR_002819 (MALAT1)] were selected for validation. Four of them were significantly downregulated in HCC tissues compared with NT tissues (P = 0.012, 0.045, 0.000 and 0.000, respectively), and the expression level of MALAT1 showed no significant difference (P = 0.114). CONCLUSION: This study identified a set of lncRNAs differentially expressed in HCC tissues and provided useful information for exploring potential therapeutic targets and diagnostic biomarkers of this cancer.

No-bond (31)P-(31)P indirect dipolar couplings, which arise from the transmission of nuclear spin polarization through interaction of proximal nonbonded electron pairs have been investigated in the solid state for a series of closely related substituted P,P-[3]ferrocenophanes and model systems. Through variation and combination of ligands (phenyl, cyclohexyl, isopropyl) at the two phosphorus sites, the P···P distances in these compounds can be varied from 3.49 to 4.06 Å. Thus, the distance dependence of the indirect no-bond coupling constant J(nb) can be studied in a series of closely related compounds. One- and two-dimensional solid-state NMR experiments serve to establish the character of these couplings and to measure the isotropic coupling constants J(iso), which were found to range between 12 and 250 Hz. To develop an understanding of the magnitude of J(nb) in terms of molecular structure, their dependences on intramolecular internuclear distances and relative orbital orientations is discussed by DFT-calculations on suitable models. In agreement with the literature the dependence of J(nb) on the P···P distance is found to be exponential; however, the steepness of this curve is highly dependent on the internuclear equilibrium distance. For a quantitative description, the off-diagonal elements of the expectation value of the Kohn-Sham-Fock operator in the LMO basis for the LMOs of the two phosphorus lone-pairs is proposed. This parameter correlates linearly with the calculated J(nb) values and possesses the same distance-dependence. In addition, the simulations indicate a distinct dependence of J(nb) on the dihedral angle defined by the two C-P bonds providing ligation to the molecular backbone. For disordered materials or those featuring multiple sites, conformers, and/or polymorphism, a new double-quantum NMR method termed DQ-DRENAR can be used to conveniently measure internuclear (31)P-(31)P distances. If conducted on compounds with known P···P distances, such measurements can also serve to estimate the magnitude of the anisotropy ΔJ of these no-bond indirect spin-spin couplings. The DFT results suggest that in the present series of compounds the magnitude of ΔJ is strongly correlated with that of the isotropic component, as both parameters have analogous distance dependences. While our studies indicate a sizable J-anisotropy for the model compound 1,8-bis(diphenylphosphino)napthalene (ΔJ ~ -70 Hz), the corresponding values for the P,P-[3]ferrocenophanes are significantly smaller, affecting their DQ-DRENAR curves only in a minor way. Based on the above insights, the structural aspects of conformational disorder and polymorphism observed in some of the P,P-[3]ferrocenophanes are discussed.

A series of (NaPO3)1–x(Ga2O3)x glasses (0 ≤ x ≤ 0.35) prepared by conventional melt-quenching methods has been structurally characterized by various complementary high resolution one-dimensional and two-dimensional (2D) solid state magic angle spinning nuclear magnetic resonance (MAS NMR) techniques, which were validated by corresponding experiments on the crystalline model compounds GaPO4 (quartz) and Ga(PO3)3. Alloying NaPO3 glass by Ga2O3 results in a marked increase in the glass transition temperature, similar to the effect observed with Al2O3. At the atomic level, multiple phosphate species QnmGa (n = 0, 1, and 2; m = 0, 1, 2, and 3) can be observed. Here n denotes the number of P–O–P and m the number of P–O–Ga linkages, and (m + n ≤ 4). For resolved resonances, the value of n can be quantified by 2D J-resolved spectroscopy, refocused INADEQUATE, and a recently developed homonuclear dipolar recoupling method termed DQ-DRENAR (double-quantum based dipolar recoupling effects nuclear alignment reduction...

The structural aspects of the glass-to-crystal transition in the technologically important ion conducting glass ceramic system Li1+xAlxGe2–x(PO4)3 (0 ≤ x ≤ 0.75) have been examined by complementary multinuclear solid state nuclear magnetic single and double-resonance experiments. In the crystalline state, the materials form solid solutions in the NASICON structure, with additional nanocrystalline AlPO4 present at x values ≥0.5. Substitution of Al in the octahedral Ge sites results in a binomial distribution of multiple phosphate species, which differ in the number P–O–Al and P–O–Ge linkages and can be differentiated by 31P chemical shift and 31P{27Al} rotational echo adiabatic passage double resonance (REAPDOR) spectroscopies. The detailed quantitative analysis of these data, of complementary 27Al{31P} rotational echo double resonance (REDOR) and of homonuclear 31P–31P double quantum NMR studies suggest that the AlO6 coordination polyhedra are noticeably expanded compared to the GeO6 sites in the NASICON-...

Glasses along the composition line 0.5Al2O3–xSiO2 (1 ≤ x ≤ 6) were prepared via a novel sol–gel route using tetraethylorthosilicate and aluminum lactate as precursors. The structural evolution from solution to gel to glass is monitored by standard 27Al and 29Si nuclear magnetic resonance (NMR) spectroscopies, revealing important insights about molecular level mechanisms occurring at the various stages of glass formation. Under the experimental conditions reported, silica and alumina precursors undergo homoatomic condensation processes when the gel is heat treated at about 100 and 300 °C, respectively, and only little heteroatomic co-condensation occurs in this temperature range. The latter is promoted only upon elimination of the residual lactate and water ligands upon annealing the gels above 300 °C. Following calcination at 650 °C, mesoporous glasses are obtained, having average pore diameter of about 3 nm and a surface areas near 500 m2/g. Si–O–Al connectivities are detected by 29Si magic angle spinning (MAS)-NMR. 27Al MAS-NMR spectra reveal aluminum in four-, five- and six-coordination. The spectra differ significantly from those of other sol–gel derived Al2O3–SiO2 materials prepared from different precursor routes, suggesting that the lactate route results in a higher degree of compositional homogeneity.

A luminescent inorganic-organic hybrid material was synthesized by covalent immobilization of a europium bipyridine carboxylate complex on the inner pore walls of the mesoporous silica host MCM-41 using the grafting method. Guest-host binding was achieved through double functionalization of the host surface with organosilane reagents (trimethylsilyl, TMS, and aminopropyltriethoxysilane, APTES) followed by reaction of the active amino sites of the APTES residue with the ligand 2,2'-bipyridyl-6,6'-dicarboxylic acid. Addition of EuCl3 solution dissolved in ethanol results in the formation of an immobilized complex having the probable formula Eu(L)x(3 ≥ x ≥ 1)(H2O)y, whose detailed photophysical properties were investigated. In the final step, an additional 2,2'-bipyridine-6 monocarboxylic acid ligand was added in an attempt to complete the coordination sphere of the rare earth ion. Each of the synthesis steps was monitored by (1)H, (13)C, and (29)Si solid state NMR spectroscopies, allowing for a quantitative assessment of the progress of the reaction and the influence of the paramagnetic species on the spectra. Based on these data and additional characterizations by chemical analysis, thermogravimetric analysis (TGA), N2 sorption, X-ray diffraction and FT-IR spectroscopy, a comprehensive quantitative picture of the covalent binding and complexation process was developed.

This letter reports the ultrabroadband infrared luminescence from 1000- to 1700-nm wavelength range and demonstrate optical amplification at the second optical communication window in a novel bismuth-doped germanosilicate glass. The full-width at half-maximum of the luminescence is about 300 nm and the optical gain is larger than 1.37 within the wavelength region from 1272 to 1348 nm with pump power 0.97 W. This material could be useful to fabricate ultrabroadband optical fiber amplifiers.

Transparent Ni2+-doped β-Ga2O3 glass–ceramics were synthesized. The nanocrystal phase in the glass–ceramics was identified to be β-Ga2O3 and its size was about 3.6 nm. It was confirmed from the absorption spectra that the ligand environment of Ni2+ ions changed from the trigonal bi-pyramid fivefold sites in the as-cast glass to the octahedral sites in the glass–ceramics. The broadband infrared emission centering at 1270 nm with full width at half maximum (FWHM) of more than 250 nm was observed. The fluorescence lifetime was about 1.1 μs at room temperature. The observed infrared emission could be attributed to the 3T2g (3F )→3A2g (3F ) transition of octahedral Ni2+ ions. It is suggested that the Ni2+-doped transparent β-Ga2O3 glass–ceramics with broad bandwidth and long lifetime have a potential as a broadband amplification medium.