Epstein-barr virus infections induce aberrant osteoclastogenesis in immune system-humanized NOD/Shi-scid/IL-2RγCnull mice.

Epstein-Barr virus (EBV) and other viral infections are possible triggers of autoimmune diseases, such as rheumatoid arthritis (RA). To analyze the causative relationship between EBV infections and RA development, we performed experiment on humanized NOD/Shi-scid/IL-2RγCnull (hu-NOG) mice reconstituted human immune system components and infected with EBV. In EBV-infected hu-NOG mice, breakdown of knee joint bones was found to be accompanied by the accumulation of receptor activator of nuclear factor-κB (NF-κB) (RANK) ligand (RANKL), a key factor in osteoclastogenesis, human CD19 and EBV-encoded small RNA (EBER)-bearing cells. Accumulation of these cells expanded in the bone marrow adjacent to the bone breakage, showing a histological feature like to that in bone marrow edema. On the other hand, human RANK/human matrix metalloprotease-9 (MMP-9) positive, osteoclast-like cells were found at broken bone portion of EBV-infected mouse knee joint. In addition, human macrophage-colony stimulating factor (M-CSF), an essential factor in development of osteoclasts, evidently expressed in spleen and bone marrow of EBV-infected humanized mice. Furthermore, RANKL and M-CSF were identified at certain period of EBV-transformed B lymphoblastoid cells (BLBCs) derived from umbilical cord blood lymphocytes. Co-culturing bone marrow cells of hu-NOG mice with EBV-transformed BLBCs resulted in the induction of a multinucleated cell population positive for tartrate-resistant acid phosphatase and human MMP-9 which indicating human osteoclast-like cells. These findings suggest that EBV-infected BLBCs induce human aberrant osteoclastogenesis, which cause erosive arthritis in the joints.

Involvement of Epstein-Barr virus in the development and spontaneous regression of methotrexate-associated lymphoproliferative disorder in patients with rheumatoid arthritis.

OBJECTIVES: Conventionally, some patients with methotrexate-associated lymphoproliferative disorder (MTX-LPD) undergo spontaneous tumour regression after cessation of MTX. Although the involvement of Epstein-Barr virus (EBV) in the development and spontaneous regression has been suggested, the underlying mechanism remains unknown. In this study, we analysed patients who had developed MTX-LPD to evaluate the association between the development and spontaneous regression of MTX-LPD with EBV. METHODS: We analysed the age, stage, disease activity, MTX dose, lymphocyte count, EBV real-time polymerase chain reaction (PCR) test value, and EBV-encoded small RNA (EBER) positivity rate in patients with MTX-LPD at our hospital. Moreover, we investigated the factors related to spontaneous regression, which is a characteristic of MTX-LPD. RESULTS: Thirty-four patients were enrolled in this study. The MTX dose at LPD onset was 8.3±2.0 mg/week, and the total dose of MTX was 1,530.3±779.2 mg. The EBV load in the peripheral blood was 270.4±431.8 copy/µL, and the pathological tissues of 17 of 34 (50%) patients tested positive for EBER. Twenty-one patients had spontaneous regression after discontinuation of MTX. The factors related to spontaneous regression were examined using a univariate analysis, and the EBV real-time PCR test value in the peripheral blood, EBER in pathological tissues, and improvement rate of lymphocyte count were considered significant factors. The EBV real-time PCR test value in the peripheral blood was defined as an independent factor of spontaneous regression using a multivariate analysis of related factors. CONCLUSIONS: EBV may be involved in the development of MTX-LPD and its spontaneous regression.

Optical Trapping-Polarized Raman Microspectroscopy of Single Ethanol Aerosol Microdroplets: Droplet Size Effects on Rotational Relaxation Time and Viscosity.

Optical trapping-polarized Raman microspectroscopy of single ethanol (EtOH) microdroplets with a diameter (d) of 6.1-16.5 µm levitated in an EtOH vapor-saturated air/N2 gas atmosphere has been explored to elucidate the vibrational and rotational motions of EtOH in the droplets at 22.0 °C. The Raman spectral bandwidth of the C-C stretching vibrational mode observed for an aerosol EtOH microdroplet was narrower than that of bulk EtOH, suggesting that the vibrational/rotational motions of EtOH in the aerosol system were restricted compared to those in the bulk system. In practice, polarized Raman microspectroscopy demonstrated that the rotational relaxation time (τrot) of EtOH in an aerosol microdroplet with d = 16. 5 µm was slower (2.33 ps) than that in a bulk EtOH (1.65 ps), while the vibrational relaxation times (τvib) in the aerosol and bulk EtOH systems were almost comparable with one another: 0.86-0.98 ps. Furthermore, although the τvib value of an aerosol EtOH microdroplet was almost unchanged irrespective of d as described above, the τrot value increased from 2.33 to 3.57 ps with a decrease in d from 16.5 to 6.1 µm, which corresponded to the increase in EtOH viscosity (η) from 1.33 to 2.04 cP with the decrease in d. The droplet size dependences of τrot and η in an aerosol EtOH microdroplet were discussed in terms of the gas/droplet interfacial molecular arrangements of EtOH and Laplace pressure experienced by a spherical EtOH microdroplet in the gas phase.

Laser-Induced Single-Molecule Extraction and Detection in Aqueous Poly(N-isopropylacrylamide)/1-Butanol Solutions.

We report photothermal phase separation of aqueous poly(N-isopropylacrylamide) (PNIPAM)/1-butanol (BuOH) solutions by focused 1064 nm laser irradiation and subsequent single microparticle formation in the solution. The single microparticle [diameter = ∼10 µm and volume = ∼picoliter (pL)] produced by laser irradiation was optically trapped by the incident 1064 nm laser beam, and this enabled us in situ Raman/fluorescence microspectroscopies of the particle. Raman spectroscopy demonstrated that the particle produced by laser irradiation was composed of PNIPAM and BuOH. In the presence of rhodamine B (RhB) in the solution, RhB was distributed from the water phase to the PNIPAM/BuOH microparticle produced by laser irradiation, as confirmed by fluorescence microspectroscopy. Laser-induced distribution/extraction of RhB to a single PNIPAM/BuOH microparticle was shown to be possible at the RhB concentration as low as 10-14 mol/dm3, where the RhB fluorescence intensity from the particle showed a step-by-step increase by every ∼3 min laser irradiation. This is the first demonstration of laser-induced simultaneous extraction and detection of single RhB molecules in solution.

Synthesis, Structures, and Photoluminescent Properties of Tricyanidonitridorhenium(V) Complexes with Bipyridine-Type Ligands.

Tricyanidonitridorhenium(V) complexes with 2,2'-bipyridine (bpy) derivatives in which the 4 and 4' positions were substituted by X, [ReN(CN)3(X2bpy)]- (X = NMe2, NH2, OMe, Me, Cl, and Br), were newly synthesized and characterized. The structures of the new complexes were determined by single-crystal X-ray analysis. UV-vis spectra of the complexes in dimethyl sulfoxide (DMSO) showed that the peak maximum wavelengths of rhenium-to-π* bpy-type-ligand charge transfer were in the range of 474-542 nm. Cyclic voltammograms in n-(C4H9)4NPF6-DMSO showed one-electron oxidation and reduction waves corresponding to the Re(VI/V) and X2bpy0/- processes, respectively. The new complexes and [ReN(CN)3bpy]- showed photoluminescence in the crystalline phase at 295 and 80 K and in DMSO at 295 K. The origin of the emission in DMSO was attributed to the triplet nature of the rhenium-to-π* bpy-type-ligand charge-transfer transition. Density functional theory calculations showed that the highest occupied and lowest unoccupied molecular orbitals were primarily localized on the dxy orbital of the rhenium and π* orbitals of the bpy-type ligand, respectively.

Optical Trapping-Microspectroscopy of Single Aerosol Microdroplets in Air: Supercooling of Dimethylsulfoxide Microdroplets.

We report temperature (T = +22.5 ∼ -57.0 °C)-controlled optical trapping of single dimethylsulfoxide (DMSO) droplets with the diameter (d) of 7-15 µm in air. Optically levitated DMSO microdroplets containing 0.1 mol/dm3 (=M) potassium iodide (KI) as an additive for reducing the vapor pressure of DMSO in air have been suggested to take supercooled liquid states even below the freezing temperature (fp) of the bulk DMSO liquid (fp = +18.4 °C in the presence of 0.1 M KI) as seen in bright-field microscopic observations of the droplet. Clear evidence for supercooling of an aerosol DMSO microdroplet below fp has been obtained by in situ optical trapping-polarized Raman microspectroscopy of the droplet down to -14.9 °C. Analysis of the polarized Raman spectral data of an aerosol DMSO droplet (d = ∼10 µm) has demonstrated that the droplet at +22.5, +0.2, or -14.9 °C is characterized by the rotational relaxation time (τrot) of a DMSO molecule in the droplet being 1.95, 2.58, or 3.90 ps, respectively. On the basis of the τrot values and the Stokes-Einstein equation (τrot = 8πa3η/kBT where a, η, kB are the radius (1.883 Å) of a DMSO molecule, the viscosity in DMSO, and the Boltzmann constant, respectively), the η values in the DMSO microdroplet in air at +22.5, +0.2, or -14.9 °C have been estimated to be 2.39, 2.94, or 4.20 cP, respectively, while that of bulk DMSO liquid at +20.5 °C is 1.98 cP. We also report the T-dependence (+22.5 > T > -14.9 °C) of the viscosity in a single aerosol DMSO microdroplet (d = ∼10 µm) and the effects of aerosolization in air on the viscosity in DMSO.

Terminal Ligand (L) Effects on Zero-Magnetic-Field Splitting in the Excited Triplet States of [{Mo6Br8}L6]2- (L = Aromatic Carboxylates).

We report the emission properties of the octahedral hexamolybdenum(II) bromide-core ({Mo6Br8}4+) clusters having a series of terminal aromatic carboxylate ligands (RCOO), [{Mo6Br8}(RCOO)6]2-, in solution and crystalline phases. The acid dissociation constant of RCOOH (p Ka(L)) was shown to govern the redox and emission properties of the clusters. Temperature ( T)-controlled emission experiments (3-300 K) demonstrated that the clusters showed large T-dependent emission energies (ν̃em) and lifetimes (τem) because of zero-magnetic-field splitting in the emissive excited triplet (T1) states. The spin sublevel (Φ n, n = 1-4) model in the T1 state of the cluster explained very well the T-dependent emission characteristics (ν̃em and τem), irrespective of the clusters studied. Furthermore, we revealed that the energy difference between the lowest-energy (Φ1) and energetically upper-lying third (Φ3) or fourth spin sublevels (Φ4), Δ E13 or Δ E14, respectively, correlated very well with p Ka( L). The results are discussed in terms of the variation of the effective nuclear charge of the Mo metal center(s) in [{Mo6Br8}(RCOO)6]2- with that of p Ka(L).

Control of Emissive Excited States of Silver(I) Halogenido Coordination Polymers by a Solid Solution Approach.

Luminescent silver(I) halogenido coordination polymers [Ag2X2(PPh3)2(bpy)] n (X = I, Br, Cl) have been prepared. The iodido and bromido complexes exhibit strong blue phosphorescence assignable to the 3π-π*-excited-state of bpy, whereas the chlorido complex shows luminescence thermochromism due to the π-π*-state of bpy and charge transfer from the {Ag2Cl2} core to the bpy π*-orbital. Taking advantage of their structural similarities, we prepared a series of mixed-halogenido silver(I) complexes [Ag2(X xX'(1- x))2(PPh3)2(bpy)] n (X, X' = I, Br, Cl) at varying molar fractions as solid solutions. The mixed-halogenido complexes are as strongly luminescent as their parent complexes. The detailed study of their structure and emissive properties revealed smooth energy migration between the luminescent units and modification of the luminescence properties based on the planarity of bpy.

[{Re6Q8}(SO3)6]10- (Q = S or Se): Facile Synthesis and Properties of the Most Highly Charged Octahedral Cluster Complexes and High Magnetic Relaxivity of Their Colloids with Gd3+ Ions.

New octahedral rhenium cluster complexes [{Re6Q8}(SO3)6]10- (Q = S or Se) were synthesized starting from [{Re6Q8}(H2O)4(OH)2]·12H2O. The complexes were crystallized as sodium salts and characterized by X-ray single-crystal diffraction and elemental analyses, IR, UV/vis and luminescence spectroscopies. Magnetic relaxation data demonstrate the complex formation of the cluster units with gadolinium ions. The analysis of the magnetic relaxation rates measured at various Gd:cluster ratios and different concentrations revealed the conversion of the aggregates (Gdx[{Re6Se8}(SO3)6]y)n- into a nanoparticulate form even at x = 1 and y ≥ 1. Thus, the self-assembly of the cluster units into the nanoparticles is greatly facilitated by counterion binding with sodium cations. The concentration conditions were optimized for the formation and hydrophilization of NaxGdy[{Re6Q8}(SO3)6]-based colloids with the magnetic relaxivity values of r1(2) = 21.0(24.1) and r1(2) = 25.9(29.8) mM-1 s-1 for the {Re6S8}2+ and {Re6Se8}2+ derivatives, respectively.

Ferroelectricity and Piezoelectricity in Free-Standing Polycrystalline Films of Plastic Crystals.

Plastic crystals represent a unique compound class that is often encountered in molecules with globular structures. The highly symmetric cubic crystal structure of plastic crystals endows these materials with multiaxial ferroelectricity that allows a three-dimensional realignment of the polarization axes of the crystals, which cannot be achieved using conventional molecular ferroelectric crystals with low crystal symmetry. In this work, we focused our attention on malleability as another characteristic feature of plastic crystals. We have synthesized the new plastic/ferroelectric ionic crystals tetramethylammonium tetrachloroferrate(III) and tetramethylammonium bromotrichloroferrate(III), and discovered that free-standing translucent films can be easily prepared by pressing powdered samples of these compounds. The thus obtained polycrystalline films exhibit ferroelectric polarization switching and a relatively large piezoelectric response at room temperature. The ready availability of functional films demonstrates the practical utility of such plastic/ferroelectric crystals, and considering the vast variety of possible constituent cations and anions, a wide range of applications should be expected for these unique and attractive functional materials.

Emission Tuning of Heteroleptic Arylborane-Ruthenium(II) Complexes by Ancillary Ligands: Observation of Strickler-Berg-Type Relation.

Novel heteroleptic arylborane-ruthenium(II) complexes having a series of ancillary ligands L' ([Ru(B2bpy)L'2]2+) in CH3CN showed low-energy/intense metal-to-ligand charge transfer (MLCT)-type absorption and intense/long-lived emission compared to the reference complexes. The spectroscopic and photophysical properties of [Ru(B2bpy)L'2]2+ were shown to be manipulated synthetically by the electron-donating ability of the ancillary ligand(s). The intense and long-lived emission observed for [Ru(B2bpy)L'2]2+ in CH3CN at 298 K is responsible for the accelerated radiative and decelerated nonradiative decay processes, which are controllable through the electronic structures of the ancillary ligand(s). On the basis of the present systematic study, furthermore, we succeeded in demonstrating the Strickler-Berg-type relation between the molar absorption coefficients of the MLCT bands and the radiative rate constants of the complexes.

23-Electron Octahedral Molybdenum Cluster Complex [{Mo6I8}Cl6].

Photoactive transition metal compounds that are prone to reversible redox reactions are important for myriad applications, including catalysis, optoelectronics, and sensing. This article describes chemical and electrochemical methods to prepare cluster complex (Bu4N)[{Mo6I8}Cl6], a rare example of a 23 e- cluster complex within the family of octahedral clusters of Mo, W, and Re. The low temperature and room temperature crystal structures; electronic structure; and the magnetic, optical, and electrochemical properties of this complex are described.

Zero-Magnetic-Field Splitting in the Excited Triplet States of Octahedral Hexanuclear Molybdenum(II) Clusters: [{Mo6X8}Y6]2- (X, Y = Cl, Br, I).

The temperature ( T) dependences of the emissions from the tetra- n-butylammonium salts of [{Mo6X8}Y6]2- (X, Y = Cl, Br, and I) in optically transparent polyethylene glycol dimethacrylate matrixes were studied in the T range of 3-300 K. [{Mo6Cl8}Y6]2-, [{Mo6Br8}Y6]2-, and [{Mo6I8}I6]2- showed the T-dependent emission characteristics similar to those of other hexanuclear Mo(II), Re(III), and W(II) clusters reported previously, while [{Mo6I8}Br6]2- and [{Mo6I8}Cl6]2- exhibited the emission properties different from those of other [{Mo6X8}Y6]2- clusters. The photophysical behavior of these clusters was explained by the excited triplet state spin-sublevel ( Φn, n = 1-4) model irrespective of the nature of X and Y. The zero-magnetic-field splitting energies between the lowest energy (Φ1) and the higher energy spin sublevels (Φ4 or Φ3) caused by the first- or second-order spin-orbit coupling, Δ E14 or Δ E13, were evaluated to be 620-870 or 50-99 cm-1, respectively. We found the linear correlation between the Δ E14 or Δ E13 value and the fourth power of the atomic number ( Z) of the inner halide X: Δ E14 or Δ E13 vs { Z(X)}4 (correlation coefficient: cc = ∼ 0.999). Furthermore, we also found the correlation between Δ E14 or Δ E13 and the 95Mo NMR chemical shift of the cluster. These findings gave very important insight into the spin-orbit coupling and zero-magnetic-field splitting in the excited triplet states of transition metal complexes.

Highly Sensitive Detection of Organic Molecules on the Basis of a Poly(N-isopropylacrylamide) Microassembly Formed by Plasmonic Optical Trapping.

We demonstrate that a poly(N-isopropylacrylamide) (PNIPAM) microassembly, formed by plasmonic optical trapping, can provide the platform for a highly sensitive detection technique for fluorescent and nonfluorescent organic molecules dissolved in aqueous solution. PNIPAM microassemblies can be easily formed by a combination with a photothermal effect and an enhanced optical force. These physical phenomena were obtained through resonant excitation of localized surface plasmon (LSP). Sparsely distributed fluorescent or nonfluorescent molecules dissolved in solution can be extracted into the PNIPAM assembly, resulting in an increase in fluorescence or Raman signals. In particular, we successfully detected quite small amounts of analytes (rhodamine B) at the 10-9 mol/L level. Using LSP is an alternative approach in analytical chemistry and can be used in addition to surface enhanced Raman scattering and surface enhanced fluorescence.

A novel multimode sensor showing cation-dependent fluorescence colour.

A novel sensor, 4-[2-(9-anthryl)ethynyl]-1,10-phenanthroline (1), exhibits highly intense fluorescent in the wavelength region of 440-600 nm (maximum wavelength (λf) = 470 nm) with the quantum yield (Φf) and lifetime (τf) being 0.90 and 4.2 ns, respectively, in CH3CN at 298 K. In the presence of a divalent cation (M2+ = Ba2+, Ca2+, Mg2+, or Zn2+) in CH3CN, sensor 1 can tightly bind M2+ and shows intense fluorescent (Φf = 0.90-0.19, τf = 2.1-6.9 ns) with the color being dependent on the nature of M2+ (λf = 514-584 nm). The results demonstrate that a single fluorescent sensor 1 is capable of simultaneous identification and quantitation of M2+ based on λf and the fluorescent intensity (Φf), respectively. The fluorescence maximum energy of the [1-M2+] complex is shown to correlate linearly with the pKa value of M2+. The spectroscopic and photophysical properties of sensor 1 in the absence and presence of M2+ are also discussed.

Zero-Magnetic-Field Splitting in the Excited Triplet States of Octahedral Hexanuclear Molybdenum(II) Clusters: [{Mo6X8}(n-C3F7COO)6]2- (X = Cl, Br, or I).

Temperature (T)-dependent emission from [{Mo6X8}(n-C3F7COO)6]2- (X = Cl (1), Br (2), and I (3)) in optically transparent polyethylene glycol dimethacrylate matrices were studied in 3 K < T < 300 K to elucidate the spectroscopic and photophysical properties of the clusters, in special reference to zero-magnetic-field splitting (zfs) in the lowest-energy excited triplet states (T1) of the clusters. The cluster complexes 1 and 2 showed the T-dependent emission characteristics similar to those of [{Mo6Cl8}Cl6]2-, while 3 exhibited emission properties different completely from those of 1 and 2. Such T-dependent emission characteristics of 1, 2, and 3 were explained successfully by the excited triplet state spin-sublevel (Φn, n = 1-4) model. The zfs energies between the lowest-energy (Φ1) and highest-energy (Φ4) spin sublevels, ΔE14, resulted by the first-order spin-orbit coupling, were evaluated to be 650, 720, and 1000 cm-1 for 1, 2, and 3, respectively. The emission spectra of 1, 2, and 3 in CH3CN at 298 K were reproduced very well by the ΔE14 values and the population percentages of Φn at 300 K. We also report that the ΔE14 values of the clusters correlate linearly with the fourth power of the atomic number (Z) of X: ΔE14 ∝ {Z(X)}4.

Quasi-One-Step Six-Electron Electrochemical Reduction of an Octahedral Hexanuclear Molybdenum(II) Cluster.

We report for the first time quasi-one-step six-electron electrochemical reduction of a new hexanuclear molybdenum(II) bromide cluster having terminal 3,5-dinitrobenzoate ligands: [Mo6Br8(DNBA)6]2-. The electrochemical responses of the cluster were studied based on cyclic (CV), differential pulse, and normal pulse voltammetries, together with the analytical simulations of the CV and spectroelectrochemistry. CV simulations have revealed that the electrochemical reaction of the cluster proceeds in an EEEEEE scheme, and the potential differences between the two adjacent reduction steps are in the range of 15-30 mV. These potential differences indicate quite smooth and quasi-one-step six-electron reduction of the cluster.

Synthetic Tuning of Redox, Spectroscopic, and Photophysical Properties of {Mo6I8}(4+) Core Cluster Complexes by Terminal Carboxylate Ligands.

The reactions between the tetra-n-butylammonium salt of [{Mo6I8}I6](2-) and silver carboxylates RCOOAg (R = CH3 (1), C(CH3)3 (2), α-C4H3O (3), C6H5 (4), α-C10H7 (5), or C2F5 (6)) in CH2Cl2 afforded new carboxylate complexes [{Mo6I8}(RCOO)6](2-). The complexes were characterized by X-ray single-crystal diffraction and elemental analysis, cyclic/differential pulse voltammetry, and IR, NMR, and UV-visible spectroscopies. The emission properties of the complexes 1-6, and those of the earlier reported complexes with R = CF3 (7) and n-C3F7 (8), were studied both in acetonitrile solution and in the solid state. In deaerated CH3CN at 298 K, all of the complexes 1-8 exhibit intense and long-lived emission with the quantum yield and lifetime being 0.48-0.73 and 283-359 µs, respectively. The oxidation (Eox)/reduction (Ered) potentials of the complexes correlate linearly with the pKa value of the terminal carboxylate ligands L = RCOO (pKa(L)). Reflecting the pKa(L) dependences of Eox/Ered, the emission energy (νem) of the complexes was also shown to correlate with pKa(L). The present study successfully demonstrates synthetic tuning of the redox, spectroscopic, and photophysical characteristics of a {Mo6I8}(4+)-based cluster complex with pKa(L).

Self-assembly formed by a short DNA probe pair: Application for highly sensitive mRNA species detection without reverse transcription.

We describe a novel technology for detecting nucleic acids: Probe Alteration Link Self-Assembly Reactions (PALSAR). PALSAR comprises DNA self-assembly of pairs of short DNA probes formed by alternate hybridization of three complementary regions in a pair of honeycomb probes (HCPs). Self-assembly occurs at designated salt concentrations and reaction temperatures and requires no enzymes. We prepared pairs of HCPs to detect mRNAs encoded by the GAPDH gene ß-actin (BA) gene, CD3D gene, CD4 gene, major vault protein (MV) gene and the signalling lymphocytic activation molecule-associated protein (SAP) gene, and succeeded in quantitatively detecting these mRNAs. PALSAR could detect mRNA directly without synthesizing cDNA. Moreover, multiple mRNAs could be detected simultaneously in a single reaction tube and there was a good correlation between the results obtained PALSAR and those by real-time PCR.