Phase wavefront perturbation calculation model for spectroscopic refractive index matching of hybrid materials.

A low-cost flexible spectroscopic refractive index matching (SRIM) material with bandpass filtering properties without incidence angle and polarization dependence by randomly dispersing inorganic C a F 2 particles in organic polydimethylsiloxane (PDMS) materials was proposed in our previous study. Since the micron size of the dispersed particles is much larger than the visible wavelength, the calculation based on the commonly used finite-difference time-domain (FDTD) method to simulate light propagation through the SRIM material is too bulky; however, on the other hand, the light tracing method based on Monte Carlo theory in our previous study cannot adequately explain the process. Therefore, a novel approximate calculation model, to the best of our knowledge, based on phase wavefront perturbation is proposed that can well explain the propagation of light through this SRIM sample material and can also be used to approximate the soft scattering of light through composite materials with small refractive index differences, such as translucent ceramics. The model simplifies the complex superposition of wavefront phase disturbances and the calculation of scattered light propagation in space. The scattered and nonscattered light ratios; the light intensity distribution after transmission through the spectroscopic material; and the influence of absorption attenuation of the PDMS organic material on the spectroscopic performance are also considered. The simulation results based on the model are in great agreement with the experimental results. This work is important to further improve the performance of SRIM materials.

Ink-jet printed, blended polymer-based microdisk resonators for controlling non-specific adsorption of biomolecules: publisher's note.

This publisher's note contains corrections to Opt. Lett.46, 262 (2021).OPLEDP0146-959210.1364/OL.412993.

On-demand inkjet-printed microdisk laser with air cladding by liquid flow microetching.

We have novelly, to the best of our knowledge, developed the liquid flow microetching method that can treat a single microdisk in a microregion with precise position control for inkjet-printed microdisk lasers. The injection-drain wet etching setup consisted of two microneedles that successfully performed a formation of a fine undercut structure of an inkjet-printed microdisk on a pre-pedestal layer through the individual wet etching process. Then measurement of the undercut structure using scanning electron microscopy and lasing characteristics with whispering gallery modes were carried out to demonstrate performance of the etched microdisks. The measured lasing threshold decreased by half compared with that of the unetched microdisk directly printed on a fluorine-type film. A point to note is that this etching method exhibits an excellent undercut and lasing characteristics even when using a clad pre-pedestal layer having a refractive index higher than that of core microdisks. This technique, combined with inkjet printing, offers a powerful tool for individually designing a microdisk and can help develop novel devices that comprise several inkjet-printed microdisks being evanescently coupled.

Changes in optical characteristics induced by polymer blending in printed colloidal quantum dots microlasers.

On-chip microlasers are desirable to meet the different control requirements and unique demands in different application scenarios. In this work, we obtained the on-chip microlaser by printing pixelated CdSe/ZnS colloidal quantum dots (CQDs), incorporating the quantum dot self-assembly mechanism and the external cavity-free configuration. The spectral purity of the microlaser can be significantly improved by slightly blending polymer into the CQD matrix. The quasitoroid profile was gradually changed to microdisks as the polystyrene (PS) concentration increased from 0 wt.% to 10 wt.%. Specially, when the PS solution varied from 0 wt.% to 1 wt.%, the lasing threshold of 1.4 µJ/mm2 was increased up to 14 µJ/mm2, meanwhile the emission wavelength range showed a 25 nm blue-shift approximately. The easy printing technologies and the low-cost polymer blending method employed in the obtained microlasers will further facilitate the development of printing photonics and electronics, especially in the high-performance microlaser displays and high-precision sensors.

Demonstration of on-chip quantum dot microcavity lasers in a molecularly engineered annular groove.

The on-chip quantum dot (QD) microcavity laser engineered on an annular groove made of fused silica was demonstrated based on the external quasi-cavity configuration. By incorporating an appropriate dose of polymer into QD film, the spectral purity of the lasing spectrum was significantly enhanced. In contrast to the dye microcavity laser embedded on the same trench profile, a QD laser possesses a lifetime that is over 10 times longer. We have introduced a unique two-step quantum gain deposition process that has remarkably reduced the wavelength drifts of laser emissions in an aqueous environment by approximately 400%. The reconfigurable cavity platform in combination with an appropriately engineered quantum gain medium embedded onto it promises to enable photostable chip-scale coherent light sources for various photonic, chemical, and biochemical sensing applications.

Organic-inorganic hybrid microdisk laser with dye and silica mixed doping prepared by ink-jet printing method.

We developed an ink-jet printing method for fabricating inorganic microdisks at room temperature, which is much lower than the melting point of solid-state inorganic oxide, and have fabricated an organic-inorganic hybrid microdisk laser. Silica was used as the inorganic disk material, and microdisk-shaped aggregates were formed by the ink-jet printing method using a solution in which nanosilica particles were dispersed in propylene glycol monomethylether (PGME) solvent. Then, a microdisk capable of laser oscillation was also prepared by preliminarily adding the laser dye rhodamine 6G to the ink to form a mixed organic material. The structural evaluation of the printed microdisk was first conducted using an optical microscope, a scanning electron microscope (SEM), and an atomic force microscope (AFM). The results of laser oscillation evaluation by optical excitation showed that the printed microdisk sufficiently functions as an optical resonator with a low optical loss. In these evaluations, excellent values such as a surface roughness of 5.83 nm from root mean square (R. M. S.) which is one forth smaller than the particle diameter, and a laser oscillation threshold of 4.76 µJ/mm2 at a wavelength of 601.4 nm were obtained. To the best of our knowledge, this is the first time that an inorganic microdisk has been fabricated at room temperature to realize an organic-inorganic hybrid microdisk laser.

Effects of edge inclination angles on whispering-gallery modes in printable wedge microdisk lasers.

The ink-jet technique was developed to print the wedge polymer microdisk lasers. The characterization of these lasers was implemented using a free-space optics measurement setup. It was found that disks of larger edge inclination angles have a larger free spectral range (FSR) and a lower resonance wavelength difference between the fundamental transverse electric (TE) and transverse magnetic (TM) whispering-gallery modes (WGMs). This behavior was also confirmed with simulations based on the modified Oxborrow's model with perfectly matched layers (PMLs), which was adopted to accurately calculate the eigenfrequencies, electric field distributions, and quality parameters of modes in the axisymmetric microdisk resonators. Combined with the nearly equivalent quality factor (Q-factor) and finesse factor (F-factor) variations, the correlations between the TE and left adjacent TM modes were theoretically demonstrated. When the edge inclination angle is varied, the distinguishable mode distribution facilitates the precise estimation of a resonance wavelength shift. Therefore, the flexible and efficient nature of wedge polymer microdisk lasers extends their potential applications in precision sensing technology.

[A multicenter study of the antimicrobial susceptibility of Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis from community acquired infections in Saitama, Japan].

We examined regional surveillance of antimicrobial susceptibility of community acquired bacterial pathogens from patients in Saitama, Japan. The fourth-year survey was conducted in three of the period 2007-2010 (period I, 2007-2008; period II, 2008-2009; period III, 2009-2010). Antimicrobial susceptibility testing was conducted at the central reference laboratory according to the method recommended by Japanese Society of Chemotherapy using maximum 13 antibacterial agents. Susceptibility testing was evaluable with 789 strains (227 Streptococcus pneumoniae, 148 Streptococcus pyogenes, 220 Haemophilus influenzae, and 194 Moraxella catarrhalis). Ratio of penicillin-susceptible S. pneumoniae (PSSP, MIC of benzylpenicillin ≤ 0.06 µg/mL) was 43.5% (period I), 43.5% (period II) and 55.8% (period III), and those of erythromycin-sensitive and azithromycin-sensitive S. pyogenes were 100% and 65.5% (period I), 47.9% and 47.9% (period II), 29.4%, and 29.4% (period III) , respectively. Among H. influenzae, ß-lactamase-nonproducing ampicillin-resistant isolates were 34.9% (period I), 25.8% (period II), and 17.1% (period III); however, ß-lactamase-nonproducing ampicillin-intermediately resistant isolates were 19.8% (period I), 26.9% (period II), and 29.3% (period III). Regarding M. catarrhalis, macrolides showed potent activities, with MIC90s of ≤ 0.25-0.5 µg/mL, and fluoroquinolones showed strong activities, with MIC90s ≤0.03-0.125 µg/mL. The result of this survey indicated that the trends observed were similar to the results of previous nationwide surveillance.

Fundamental characteristics of degradation-recoverable solid-state DFB polymer laser.

A novel solid-state dye laser with degradation recovery was proposed and demonstrated. Polydimethylsiloxane was used as a nanoporous solid matrix to enable the internal circulation of dye molecules in the solid state. An internal circulation model for the dye molecules was also proposed and verified numerically by assuming molecular mobility and using a proposed diffusion equation. The durability of the laser was increased 20.5-fold compared with that of a conventional polymethylmethacrylate laser. This novel laser solves the low-durability problem of dye-doped polymer lasers.

Optical bending sensor using distributed feedback solid state dye lasers on optical fiber.

Novel type of optical fiber sensor was proposed and demonstrated. The print-like fabrication technique fabricates multiple distributed feedback solid state dye lasers on a polymeric optical fiber (POF) with tapered coupling. This multi-active-sidecore structure was easily fabricated and provides multiple functions. Mounting the lasers on the same point of a multimode POF demonstrated a bending radius sensitivity of 20 m without any supports. Two axis directional sensing without cross talk was also confirmed. A more complicated mounting formation can demonstrate a twisted POF. The temperature property of the sensor was also studied, and elimination of the temperature influence was experimentally attained.

[A single-center prospective study of viral infection in community-acquired pneumonia in adults].

From July, 2008 to March, 2009, 125 adults with community-acquired pneumonia (CAP) who were admitted to our hospital were retrospectively investigated to elucidate the characteristics of viral infection in adult CAP in Japan. Nasopharyngeal swabs for real-time polymerase chain reaction for 7 types of influenza virus, rhinovirus, respiratory synctial virus, human metapneumovirus, parainfluenza virus, coronavirus, and enterovirus were obtained. Diagnoses of viral infections were established according to positive results in real-time polymerase chain reaction and influenza rapid diagnostic testing, and based on a fourfold increase in antibody titer of influenza virus antibody in paired sera. Overall, a pathogen was identified in 74 patients (59.8%). Of these pathogens, 47 (37.6%) were bacterial, 17 (13.6%) were viral, and 10 (8.0%) were mixed virus and bacterial infection. Influenza virus (n = 12; 9.6%), rhinovirus (n = 8; 6.4%), respiratory syncytial virus (n = 8; 6.4%), and parainfluenza virus (n = 6; 4.8%) were detected. Adenovirus, coronavirus or enterovirus was not detected. Sore throat was more frequently found in patients with viral pneumonia than in those with non-viral pneumonia. Higher age and pneumococcal pneumonia were factors which contributed to severity in the present cases. It is difficult to distinguish viral pneumonia from non-viral pneumonia by clinical findings, and there were few clinically meaningful differences in presentation and severity, and no differences in severity or outcomes according to either the presence or absence of viral infection. Further studies are needed to clarify the possible significance of viral infection in CAP.

Dual-wavelength mode-locked Yb:YAG ceramic laser in single cavity.

We experimentally demonstrated a dual-wavelength independently mode-locked Yb:YAG ceramic laser in a single cavity. Dual-wavelength mode locking at 1033.6 and 1047.6 nm was operated simultaneously in one beam. Each pulse width was measured to be approximately 380 fs using an autocorrelator. The spectral widths were 4.50 nm centered at 1033.6 nm and 3.08 nm centered at 1047.6 nm. To the best of our knowledge, this is the first dual-wavelength mode locking achieved in Yb-doped solid-state lasers.

Comparison between Patients with Chest Infection due to Klebsiella spp. and Streptococcus pneumoniae.

Objective In Japan, the aging demographic structure is becoming pronounced, and the full-blown graying of society appears not far off, which indicates an increasing population that will require healthcare contact. Klebsiella spp. are major pathogens in healthcare-associated infections, and their importance is increasing. The aim of this study was to clarify the characteristics of Klebsiella spp. chest infections by evaluating the differences in the characteristics of chest infections caused by Klebsiella spp. and pneumoniae. Methods We conducted a retrospective study of consecutive patients hospitalized with pneumonia, lung abscess/necrotizing pneumonia, and empyema due to Klebsiella spp. and S. pneumoniae for 15 years at our institution in Saitama, Japan. Patients Patients with chest infections due to Klebsiella spp. (K group, n=76) and S. pneumoniae (S group, n=446) were included. Results The K group more frequently was male, older, coinfected by Pseudomonas aeruginosa, and had diabetes mellitus, a history of upper digestive system surgery, alcohol drinking habit, a smoking habit, and an impaired premorbid performance status than the S group. The percentages of lung abscesses or necrotizing pneumonia (31.6% vs. 0.9%) and empyema without pulmonary parenchymal shadow (3.9% vs. 0.7%) were higher in the K group than those in the S group. Severity on admission and mortality did not differ between the groups; however, patients in the K group required a longer duration of antibiotics administration and hospital stay than those in the S group. Conclusion Klebsiella spp. chest infections have some marked characteristics when compared with pneumococcal infections, and our results serve to differentiate Klebsiella spp. infection from pneumococcal infection.

Diode-pumped mode-locked Yb:YAG ceramic laser.

A diode-pumped passively mode-locked Yb:YAG ceramic laser was demonstrated. 417 and 286 fs pulses with average powers of 250 and 25 mW were obtained at 1030 nm using 1 and 0.1% output couplers, respectively. 233 fs pulses with an average power of 20 mW were also obtained at a center wavelength of 1048.3 nm using a 0.1% output coupler. To the best of our knowledge, this is the first demonstration of a diode-pumped mode-locked Yb:YAG ceramic laser.

Synthesis and applications of novel fluorinated dendrimer-type copolymers by the use of fluoroalkanoyl peroxide as a key intermediate.

Fluoroalkanoyl peroxide reacted with 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (TTRV-Si) to afford fluoroalkyl end-capped oligomers containing some unreacted vinyl segments under very mild conditions. Fluoroalkyl end-capped cyclosiloxane oligomers containing some vinyl segments thus obtained reacted with N,N-dimethylacrylamide and fluoroalkanoyl peroxide to afford new fluorinated dendrimer-type block copolymers in good isolated yield. Similar reactions were also occurred by the use of 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane instead of TTRV-Si, and the corresponding fluorinated dendrimer-type block copolymer was obtained in good isolated yield. These fluorinated dendrimer-type block copolymers had an excellent solubility not only in water but also in traditional organic solvents including aliphatic fluorinated solvents. Interestingly, these fluorinated block copolymers were found to form the self-assembled dendrimer-type polymeric aggregates in aqueous solutions. More interestingly, these fluorinated block copolymers had an extremely higher dispersion ability of not only single-walled carbon nanotube and fullerenes but also magnetic nanoparticles into water, compared to that of the corresponding two fluoroalkyl end-capped oligomers.

Carbon-polydimethylsiloxane-based integratable optical technology for spectroscopic analysis.

A polydimethylsiloxane (PDMS)-based optical system has been demonstrated. To suppress intense background radiation due to multiple internal scatting in a transparent material, a composite structure of a carbon-PDMS compound and PDMS was proposed. The index matching of the real part of the refractive index can suppress internal scattering, and an absorption of 99-99.7% was attained by using carbon micro particles and carbon nano tubes. The black-PDMS light channel functions as a light filter for straight pass, and an optical density of 5 was obtained by bending the filter.

Nonconcordant regulation of mitochondrial respiratory complexes in the kidneys of 5/6 nephrectomized mice.

Hyperglycemia induces nonconcordant regulation of renal mitochondrial respiratory complexes, increases oxidative stress, and causes diabetic nephropathy. Hypertension is a complication associated with diabetes and involves glomerular hyperfiltration, the effects of which on mitochondrial respiratory complexes are not well understood. To investigate the effect of glomerular hyperfiltration on renal mitochondrial respiratory complexes, we used the 5/6 nephrectomized BKS. Cg-Dock7m+/+Leprdb/J, Dock7m+/+Leprdb mice (db/m-5/6Nx mice) as a model for glomerular hyperfiltration. The BKS. Cg-Dock7m+/+Leprdb/J, +Leprdb/+Leprdb mice (db/db mice), a model for type 2 diabetes, was used as the positive control. We investigated the activities and protein levels of the mitochondrial complex, and the mitochondrial DNA and adenosine triphosphate content in the kidneys of these models. Blood chemistry and renal histopathological examination were performed for characterization of the disease. Both models showed expansion of the mesangial matrix of the glomeruli, which is indicative of glomerular hyperfiltration. The activities of complexes I and IV and the protein levels of complexes I and III were nonconcordant in db/m-5/6Nx mice. In conclusion, we demonstrated that nonconcordant regulation of mitochondrial complexes in db/m-5/6Nx mice involved with glomerular hyperfiltration. The progression and/or severity of nephropathy might be affected through a synergistic effect of mitochondrial dysfunction in hyperglycemia and glomerular hyperfiltration. J. Med. Invest. 64: 255-261, August, 2017.

A case of empyema and septic arthritis due to Nocardia farcinica.

Septic arthritis due to Nocardia sp. should be suspected when a patient with risk factors such as pneumoconiosis or diabetes mellitus develops joint symptoms, especially if the patient has had nocardiosis in other sites.

Extreme ultra-low lasing threshold of full-polymeric fundamental microdisk printed with room-temperature atmospheric ink-jet technique.

We experimentally demonstrated an extreme ultra-low lasing threshold from full-polymeric fundamental microdisk cavities fabricated by a novel fabrication method, the ink-jet printing method, which is much simpler and easier than previous methods such as lithography. The ink-jet printing method provides additive, room-temperature atmospheric, rapid fabrication with only two steps: (i) stacking cladding pedestal and waveguiding disk spots using the ink-jet technique, and (ii) partial etching of the cladding pedestal envelope. Two kinds of low-viscosity polymers successfully formed microdisks with high surface homogeneity, and one of the polymers doped with LDS798 dye yielded whispering-gallery-mode lasing. The fundamental disks exhibited an extremely ultra-low lasing threshold of 0.33 µJ/mm(2) at a wavelength of 817.3 nm. To the best of our knowledge, this lasing threshold is the lowest threshold obtained among both organic and inorganic fundamental microdisk cavity lasers with a highly confined structure.