Localization and Orientation of Dye Molecules at the Surface of a Levitated Microdroplet in Air Revealed by Whispering Gallery Mode Resonances.

Microdroplets offer unique environments that accelerate chemical reactions; however, the mechanisms behind these processes remain debated. The localization and orientation of solute molecules near the droplet surface have been proposed as factors for this acceleration. Since significant reaction acceleration has been observed for electrospray- and sonic-spray-generated aerosol droplets, the analysis of microdroplets in air has become essential.

Alignment of fibrous J-aggregates and the resulting macroscopic optical anisotropy observed in static solution.

J-aggregates, which are supramolecular assemblies that exhibit unique optical properties owing to their excitonic interactions, have potential applications in artificial light-harvesting systems and fluorescence biosensing. Although J-aggregates are formed in solution, in situ observations of their structures and behaviors in solution remain scarce. In this study, we investigated the J-aggregates of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate [DiIC18(3)] in methanol/water (M/W) binary solvents using fluorescence imaging as well as polarized absorption and fluorescence measurements to explore the relationship between their structure and macroscopic optical properties under static conditions.

Synthesis of Single-Nanometer-Sized Gold Nanoparticles in Liquid-Liquid Dispersion System by Femtosecond Laser Irradiation.

Gold nanoparticles (AuNPs) show unique optical properties and catalytic activities, and their synthesis from gold ions has been widely studied. One of the additive-reagent-free and noncontact production procedures is the reduction of gold ions in solution by femtosecond laser pulses; however, the aggregation of AuNPs is unavoidable in homogeneous solution. Here, we report the synthesis of single-nanometer-sized AuNPs in a mixture of aqueous HAuCl solution and -hexane (the mixture) and in aqueous HAuCl solution (the aqueous solution) by femtosecond laser irradiation in the absence of any additive reagents.

Synthesis of Bare Iron Nanoparticles from Ferrocene Hexane Solution by Femtosecond Laser Pulses.

Iron-based nanoparticles (FeNPs) have unique and attractive properties such as superparamagnetism, biocompatibility, and catalytic activity. Although the synthesis of precious metal NPs from a metal in liquid and/or metal salt solution by a pulsed laser has been investigated, comparably little effort has been devoted to examine the production of FeNPs. Here we report the synthesis of carbon-shell free spherical NPs of iron oxide (magnetite) from ferrocene hexane solution by femtosecond near infrared laser pulses.

Real-time observation of the photoionization-induced water rearrangement dynamics in the 5-hydroxyindole-water cluster by time-resolved IR spectroscopy.

Solvation plays an essential role in controlling the mechanism and dynamics of chemical reactions in solution. The present study reveals that changes in the local solute-solvent interaction have a great impact on the timescale of solvent rearrangement dynamics. Time-resolved IR spectroscopy has been applied to a hydration rearrangement reaction in the monohydrated 5-hydroxyindole-water cluster induced by photoionization of the solute molecule.

Elevation of the Energy Threshold for Isomerization of 5-Hydroxyindole-(tert-butyl alcohol) Cluster Cations.

Isomerization between two hydrogen-bonded (H-bonded) isomers of 5-hydroxyindole-(tert-butyl alcohol) cluster cations ([5HI-(t-BuOH)]) was investigated in the gas phase. In the S state, jet-cooled 5HI-(t-BuOH) has two structural isomers, 5HI(OH)-(t-BuOH) and 5HI(NH)-(t-BuOH), in which the t-BuOH molecule is bound to the OH or the NH group of 5HI. The IR photodissociation spectrum of [5HI-(t-BuOH)] generated by two-color resonant two-photon ionization (2C-R2PI) via the S-S origin of 5HI(NH)-(t-BuOH) provided evidence of both [5HI(OH)-(t-BuOH)] and [5HI(NH)-(t-BuOH)] coexisting in the D state, indicating that [5HI(NH)-(t-BuOH)] isomerizes to [5HI(OH)-(t-BuOH)] after 2C-R2PI of 5HI(NH)-(t-BuOH).

Rearrangements of a Water Molecule in Both Directions between Two Hydrogen-Bonding Sites of 5-Hydroxyindole Cation: Experimental Determination of the Energy Threshold for the Rearrangement.

Rearrangements of a water molecule in both directions between two hydrogen-bonding (H-bonding) sites of the 5-hydroxyindole (5HI) cation was investigated in the gas phase. IR-dip spectra of jet-cooled 5HI-(H2O)1 revealed that two structural isomers, 5HI(OH)-(H2O)1 and 5HI(NH)-(H2O)1, in which a water molecule is bound to either the OH group or the NH group of 5HI, were formed in the S0 state. The IR photodissociation spectrum of [5HI-(H2O)1](+) generated by two-color resonant two-photon ionization (2C-R2PI) via the S1-S0 origin of 5HI(NH)-(H2O)1 clearly showed that [5HI(OH)-(H2O)1](+) and [5HI(NH)-(H2O)1](+) coexist in the D0 state.

Simultaneous Interaction of Hydrophilic and Hydrophobic Solvents with Ethylamino Neurotransmitter Radical Cations: Infrared Spectra of Tryptamine(+)-(H2O)m-(N2)n Clusters (m,n ≤ 3).

Solvation of biomolecules by a hydrophilic and hydrophobic environment strongly affects their structure and function. Here, the structural, vibrational, and energetic properties of size-selected clusters of the microhydrated tryptamine cation with N2 ligands, TRA(+)-(H2O)m-(N2)n (m,n ≤ 3), are characterized by infrared photodissociation spectroscopy in the 2800-3800 cm(-1) range and dispersion-corrected density functional theory calculations at the ωB97X-D/cc-pVTZ level to investigate the simultaneous solvation of this prototypical neurotransmitter by dipolar water and quadrupolar N2 ligands. In the global minimum structure of TRA(+)-H2O generated by electron ionization, H2O is strongly hydrogen-bonded (H-bonded) as proton acceptor to the acidic indolic NH group.

Macromolecular Crowding Modifies the Impact of Specific Hofmeister Ions on the Coil-Globule Transition of PNIPAM.

Macromolecular crowding alters many biological processes ranging from protein folding and enzyme reactions in vivo to the precipitation and crystallization of proteins in vitro. Herein, we have investigated the effect of specific monovalent Hofmeister salts (NaH2PO4, NaF, NaCl, NaClO4, and NaSCN) on the coil-globule transition of poly(N-isopropylacrylamide) (PNIPAM) in a crowded macromolecular environment as a model for understanding the specific-ion effect on the solubility and stability of proteins in a crowded macromolecular environment. It was found that although the salts (NaH2PO4, NaF, and NaCl) and the macromolecular crowder (polyethylene glycol) lowered the transition temperature almost independently, the macromolecular crowder had a great impact on the transition temperature in the case of the chaotropes (NaClO4 and NaSCN).

Weak hydrogen bonding motifs of ethylamino neurotransmitter radical cations in a hydrophobic environment: infrared spectra of tryptamine(+)-(N2)n clusters (n ≤ 6).

Size-selected clusters of the tryptamine cation with N2 ligands, TRA(+)-(N2)n with n = 1-6, are investigated by infrared photodissociation (IRPD) spectroscopy in the hydride stretch range and quantum chemical calculations at the ωB97X-D/cc-pVTZ level to characterize the microsolvation of this prototypical aromatic ethylamino neurotransmitter radical cation in a nonpolar solvent. Two types of structural isomers exhibiting different interaction motifs are identified for the TRA(+)-N2 dimer, namely the TRA(+)-N2(H) global minimum, in which N2 forms a linear hydrogen bond (H-bond) to the indolic NH group, and the less stable TRA(+)-N2(π) local minima, in which N2 binds to the aromatic π electron system of the indolic pyrrole ring. The IRPD spectrum of TRA(+)-(N2)2 is consistent with contributions from two structural H-bound isomers with similar calculated stabilization energies.

IR spectroscopy of monohydrated tryptamine cation: rearrangement of the intermolecular hydrogen bond induced by photoionization.

Rearrangement of intermolecular hydrogen bond in a monohydrated tryptamine cation, [TRA(H(2)O)(1)](+), has been investigated in the gas phase by IR spectroscopy and quantum chemical calculations. In the S(0) state of TRA(H(2)O)(1), a water molecule is hydrogen-bonded to the N atom of the amino group of a flexible ethylamine side chain [T. S.

Photoionization-induced water migration in the hydrated trans-formanilide cluster cation revealed by gas-phase spectroscopy and ab initio molecular dynamics simulation.

Photoionization-induced water migration in the trans-formanilide-water 1:1 cluster, FA-(H(2)O)(1), has been investigated by using IR-dip spectroscopy, quantum chemical calculations, and ab initio molecular dynamics simulations. In the S(0) state, FA-(H(2)O)(1) has two structural isomers, FA(NH)-(H(2)O)(1) and FA(CO)-(H(2)O)(1), where a water molecule is hydrogen-bonded (H-bonded) to the NH group and the CO group, respectively. In addition, the S(1)-S(0) origin transition of FA(CO)-(H(2)O)(2), where a water dimer is H-bonded to the CO group, was observed only in the [FA-(H(2)O)(1)](+) mass channel, indicating that one of the water molecules evaporates completely in the D(0) state.

Entropy-driven rearrangement of the water network at the hydrated amide group of the trans-formanilide-water cluster in the gas phase.

Photoionization-induced rearrangement of the water network in the trans-formanilide 1:4 cluster, FA-(H(2)O)(4), has been investigated by using IR-photodissociation spectroscopy and quantum chemical calculations. The IR spectrum of FA-(H(2)O)(4) in the S(0) state shows that the observed cluster has a cyclic hydrogen-bonded structure where the CO group and the NH group of FA are bridged with four water molecules, consistent with the reported structure [E. G.

Photon induced isomerization in the first excited state of the 7-azaindole-(H2O)3 cluster.

A picosecond pump and probe experiment has been applied to study the excited state dynamics of 7-azaindole-water 1 ∶ 2 and 1 ∶ 3 clusters [7AI(H(2)O)(2,3)] in the gas phase. The vibrational-mode selective Excited-State-Triple-Proton Transfer (ESTPT) in 7AI(H(2)O)(2) proposed from the frequency-resolved study has been confirmed by picosecond decays. The decay times for the vibronic states involving the ESTPT promoting mode σ(1) (850-1000 ps) are much shorter than those for the other vibronic states (2100-4600 ps).

Photoionization-induced water migration in the amide group of trans-acetanilide-(H2O)1 in the gas phase.

IR-dip spectra of trans-acetanilide-water 1:1 cluster, AA-(H(2)O)(1), have been measured for the S(0) and D(0) state in the gas phase. Two structural isomers, where a water molecule binds to the NH group or the CO group of AA, AA(NH)-(H(2)O)(1) and AA(CO)-(H(2)O)(1), are identified in the S(0) state. One-color resonance-enhanced two-photon ionization, (1 + 1) RE2PI, of AA(NH)-(H(2)O)(1) via the S(1)-S(0) origin generates [AA(NH)-(H(2)O)(1)](+) in the D(0) state, however, photoionization of [AA(CO)-(H(2)O)(1)] does not produce [AA(CO)-(H(2)O)(1)](+), leading to [AA(NH)-(H(2)O)(1)](+).

Excited-state triple-proton transfer in 7-azaindole(H(2)O)(2) and reaction path studied by electronic spectroscopy in the gas phase and quantum chemical calculations.

We have investigated the excited-state multiple-proton/hydrogen atom transfer reactions in the 7-azaindole water clusters, [7AI](H(2)O)(n) (n = 2,3), in the gas phase by combining electronic spectroscopy and quantum chemical calculations. The fluorescence excitation (FE) spectrum of 7AI(H(2)O)(2) has been observed by monitoring visible emission. In contrast, no vibronic bands are detected in the FE spectrum of 7AI(H(2)O)(3) when the visible emission is monitored.

Electronic spectra of two long-lived photoproducts: double-proton transfer in 7-hydroxyquinoline dimer in a 2-methyltetrahydrofuran glass matrix.

Photoreactions of 7-hydroxyquinoline (7-HQ) in low-temperature (77-100 K) 2-methyltetrahydrofuran glass matrices are investigated using electronic spectroscopy. We have observed fluorescence excitation and fluorescence spectra of two long-lived species generated by irradiation of UV light (230-400 nm). The dominant species responsible for the fluorescence spectrum between 470 and 600 nm was assigned to the S(1)-->S(0) (pipi*) transition of the keto form of cyclic 7-HQ dimer [(7-HQ)(2)] produced by excited-state double-proton transfer, the corresponding S(1)-S(0) fluorescence excitation spectrum of which was detected between 360 and 510 nm.

Formation of a dual hydrogen bond in the N-H...C=O moiety in the indole-(N-methylacetamide)1 cluster revealed by IR-dip spectroscopy with natural bond orbital analysis.

IR-dip spectra in the NH stretch regions have been measured for the S(0) state of the indole/N-methylacetamide 1:1 clusters (Ind-NMA(1)). We identified two structural isomers of Ind-NMA(1) that possess an N-H..

Spectroscopic study on the structural isomers of 7-azaindole(ethanol)(n) (n=1-3) and multiple-proton transfer reactions in the gas phase.

The resonance-enhanced two-photon ionization (RE2PI) and laser-induced fluorescence excitation spectra were recorded for the S(1)-S(0)(pipi( *)) region of the 7-azaindole(ethanol)(n) (n=1-3) [7AI(EtOH)(n) (n=1-3)] clusters in the gas phase to investigate the geometrical structures and the multiple-proton/hydrogen atom transfer reaction dynamics. Four and two structural isomers were identified for 7AI(EtOH)(2) and 7AI(EtOH)(3), respectively. Density functional theory calculations at the B3LYP/6-31++G( * *)/6-31G( *) level predicted four different conformations of the ethyl group for 7AI(EtOH)(2), in good agreement with the observation of the four structural isomers in the RE2PI spectra.

Charge transfer interaction of intermolecular hydrogen bonds in 7-azaindole(MeOH)n (n = 1, 2) with IR-dip spectroscopy and natural bond orbital analysis.

Resonance-enhanced two-photon ionization (RE2PI) spectra of the deuterated 7-azaindole [7AI](MeOH)(n) (n = 1-3) clusters in the 0-0 region of the S(1)-S(0) (pi pi*) transition and IR-UV ion-dip spectra of the deuterated 7AI(MeOH)(n) (n = 1, 2) in the NH and OH stretch regions are observed in the gas phase to investigate the effect of charge transfer delocalization interaction on intermolecular hydrogen bonds. Two and three isotopomers are identified for 7AI(MeOH)(1)-d(1) and 7AI(MeOH)(2)-d(2), respectively, where 7AI(MeOH)(1)-d(1) has a deuterium atom in the NH or OH group and 7AI(MeOH)(2)-d(2) has two deuterium atoms in the NH and OH groups or in the two OH groups. The local modes of the NH and OH groups are successfully observed in the IR-dip spectra upon deuteration.

Probe of the NH bond strength in 1L(a) and 1L(b) states of 7-azaindole with IR-dip spectroscopy: insights into the electronic-state dependence of the multiple proton/hydrogen transfers in hydrogen-bonded clusters.

The difference in the NH bond strengths in the (1)L(a) and (1)L(b) state of 7-azaindole is examined with the fluorescence-detected IR-dip spectroscopy. It has been found that the NH stretch fundamental (3456 cm(-1)) measured by probing the vibronic band at 280 cm(-1) above the zero-point level of (1)L(b) is remarkably red-shifted with respect to those (3483-3489 cm(-1)) obtained by probing the other six vibronic bands in the 0-717 cm(-1) region. The electronic state of the band at 280 cm(-1) was assigned to a S(1)(L(b))/S(2)(L(a)) mixing state [Kang et al.

Two patients with bepridil-induced interstitial pneumonia.

Two patients developed bepridil-induced interstitial pneumonia during treatment of arrhythmia. The first patient was a 69-year-old man who received bepridil to maintain sinus rhythm in atrial fibrillation and who developed dyspnea on the 20th day after administration. The second patient was a 72-year-old man who received bepridil for paroxysmal atrial fibrillation and who developed dyspnea on the 60th day after administration.

Cooperativity of hydrogen-bonded networks in 7-azaindole(CH3OH)n (n=2,3) clusters evidenced by IR-UV ion-dip spectroscopy and natural bond orbital analysis.

IR-UV ion-dip spectra of the 7-azaindole (7AI)(CH(3)OH)(n) (n=1-3) clusters have been measured in the hydrogen-bonded NH and OH stretching regions to investigate the stable structures of 7AI(CH(3)OH)(n) (n=1-3) in the S(0) state and the cooperativity of the H-bonding interactions in the H-bonded networks. The comparison of the IR-UV ion-dip spectra with IR spectra obtained by quantum chemistry calculations shows that 7AI(CH(3)OH)(n) (n=1-3) have cyclic H-bonded structures, where the NH group and the heteroaromatic N atom of 7AI act as the proton donor and proton acceptor, respectively. The H-bonded OH stretch fundamental of 7AI(CH(3)OH)(2) is remarkably redshifted from the corresponding fundamental of (CH(3)OH)(2) by 286 cm(-1), which is an experimental manifestation of the cooperativity in H-bonding interaction.

Cytokine and clinical predictors for treatment outcome of visually guided temporomandibular joint irrigation in patients with chronic closed lock.

Purpose: This study investigates selected predictors for clinical outcome of temporomandibular joint (TMJ) irrigation in patients with chronic closed lock (CCL).

Patients And Methods: Fifty-six patients with unilateral CCL, who underwent a visually guided TMJ irrigation (VGIR), were enrolled in this study. They were divided into either successful (s-group; n = 38) or unsuccessful groups (u-group; n = 18), according to the clinical success criteria.

Factors affecting long-term compliance of osteoporotic patients with bisphosphonate treatment and QOL assessment in actual practice: alendronate and risedronate.

The aim of our study was to examine compliance with a daily dose of 5 mg alendronate (ALN) and 2.5 mg risedronate (RDN) in actual practice, and to determine the causes of noncompliance through a questionnaire. In addition, we studied the quality of life (QOL) of patients through another disease-related questionnaire.