Gaining control on optical force by the stimulated-emission resonance effect.

The resonance between an electronic transition of a micro/nanoscale object and an incident photon flux can modify the radiation force exerted on that object, especially at an interface. It has been theoretically proposed that a non-linear stimulated emission process can also induce an optical force, however its direction will be opposite to conventional photon scattering/absorption processes. In this work, we experimentally and theoretically demonstrate that a stimulated emission process can induce a repulsive pulling optical force on a single trapped dye-doped particle. Moreover, we successfully integrate both attractive pushing (excited state absorption) and repulsive pulling (stimulated emission) resonance forces to control the overall exerted optical force on an object, validating the proposed non-linear optical resonance theory. Indeed, the results presented here will enable the optical manipulation of the exerted optical force with exquisite control and ultimately enable single particle manipulation.

Unravelling 3D Dynamics and Hydrodynamics during Incorporation of Dielectric Particles to an Optical Trapping Site.

Mapping of the spatial and temporal motion of particles inside an optical field is critical for understanding and further improvement of the 3D spatio-temporal control over their optical trapping dynamics. However, it is not trivial to capture the 3D motion, and most imaging systems only capture a 2D projection of the 3D motion, in which the information about the axial movement is not directly available. In this work, we resolve the 3D incorporation trajectories of 200 nm fluorescent polystyrene particles in an optical trapping site under different optical experimental conditions using a recently developed widefield multiplane microscope (imaging volume of 50 × 50 × 4 µm3). The particles are gathered at the focus following some preferential 3D channels that show a shallow cone distribution. We demonstrate that the radial and the axial flow speed components depend on the axial distance from the focus, which is directly related to the scattering/gradient optical forces. While particle velocities and trajectories are mainly determined by the trapping laser profile, they cannot be completely explained without considering collective effects resulting from hydrodynamic forces.

In-Hospital Mortality of Patients With Acute Type A Aortic Dissection Hospitalized on Weekends Versus Weekdays.

Background: In acute aortic dissection, weekend admissions are reported to be associated with increased mortality compared with weekday admissions. Objective: This study aimed to determine whether patients with acute type A aortic dissection (ATAAD) admitted on weekends had higher in-hospital mortality than those admitted on weekdays in the Tokyo metropolitan area, where we developed a patient-transfer system for aortic dissection. Methods: Data were collected during the first year after our transfer system began (cohort I) and in the subsequent years from 2013 to 2015 (cohort II). Results: We studied 2,339 patients (500 in cohort I; 1,839 in cohort II) with ATAAD. Patients with weekend admissions had higher in-hospital mortality than those with weekday admissions in cohort I. In association with increased interfacility transfer during weekends and reduced mortality at non-high-volume centers, the in-hospital mortality in the weekend group improved from 37.2% in cohort I to 22.2% in cohort II (P < 0.001). After inverse probability weighting adjustment, weekend admission was associated with higher in-hospital mortality in cohort I (odds ratio: 2.28; 95% confidence interval: 1.48 to 3.52; P < 0.001), but not in cohort II (odds ratio: 0.96; 95% confidence interval: 0.75 to 1.22; P = 0.731). On multivariable analyses, weekend admission was associated with higher in-hospital mortality in combined cohort I+II; the associations between weekend admission and mortality were not significant in cohort II. Conclusions: We found a significant reduction in in-hospital mortality in patients with weekend admissions for ATAAD. No mortality difference between weekend and weekday admissions was observed in the later years of the study.

Structural region essential for amyloid fibril formation in cytochrome c elucidated by optical trapping.

Amyloid fibril formation of cytochrome c is spatially and temporally controlled with a combined method of disulfide bond cross-linking of cysteine-introduced variants and optical trapping, identifying that the structural change in the region containing Ala83 is essential for the amyloid fibril formation.

The primeval optical evolving matter by optical binding inside and outside the photon beam.

Optical binding has recently gained considerable attention because it enables the light-induced assembly of many-body systems; however, this phenomenon has only been described between directly irradiated particles. Here, we demonstrate that optical binding can occur outside the focal spot of a single tightly focused laser beam. By trapping at an interface, we assemble up to three gold nanoparticles with a linear arrangement which fully-occupies the laser focus. The trapping laser is efficiently scattered by this linear alignment and interacts with particles outside the focus area, generating several discrete arc-shape potential wells with a half-wavelength periodicity. Those external nanoparticles inside the arcs show a correlated motion not only with the linear aligned particles, but also between themselves even both are not directly illuminated. We propose that the particles are optically bound outside the focal spot by the back-scattered light and multi-channel light scattering, forming a dynamic optical binding network.

Sex-Related Differences in Clinical Features and In-Hospital Outcomes of Type B Acute Aortic Dissection: A Registry Study.

Background The association between female sex and poor outcomes following surgery for type A acute aortic dissection has been reported; however, sex-related differences in clinical features and in-hospital outcomes of type B acute aortic dissection, including classic aortic dissection and intramural hematoma, remain to be elucidated. Methods and Results We studied 2372 patients with type B acute aortic dissection who were enrolled in the Tokyo Acute Aortic Super-Network Registry. There were fewer and older women than men (median age [interquartile range]: 76 years [66-84 years], n=695 versus 68 years [57-77 years], n=1677; P<0.001). Women presented to the aortic centers later than men. Women had a higher proportion of intramural hematoma (63.7% versus 53.7%, P<0.001), were medically managed more frequently (90.9% versus 86.3%, P=0.002), and had less end-organ malperfusion (2.4% versus 5.7%, P<0.001) and higher in-hospital mortality (5.3% versus 2.7%, P=0.002) than men. In multivariable analysis, age (per year, odds ratio [OR], 1.06 [95% CI, 1.03-1.08]; P<0.001), hyperlipidemia (OR, 2.09 [95% CI, 1.13-3.88]; P=0.019), painlessness (OR, 2.59 [95% CI, 1.14-5.89]; P=0.023), shock/hypotension (OR, 2.93 [95% CI, 1.21-7.11]; P=0.017), non-intramural hematoma (OR, 2.31 [95% CI, 1.32-4.05]; P=0.004), aortic rupture (OR, 26.6 [95% CI, 14.1-50.0]; P<0.001), and end-organ malperfusion (OR, 4.61 [95% CI, 2.11-10.1]; P<0.001) were associated with higher in-hospital mortality, but was not female sex (OR, 1.67 [95% CI, 0.96-2.91]; P=0.072). Conclusions Women affected with type B acute aortic dissection were older and had more intramural hematoma, a lower incidence of end-organ malperfusion, and higher in-hospital mortality than men. However, female sex was not associated with in-hospital mortality after multivariable adjustment.

Risk analysis for early mortality in emergency acute type A aortic dissection surgery: experience of Tokyo Acute Aortic Super-network.

OBJECTIVES: We investigated the various pre- and postoperative complications related to early (30-day) mortality after open surgery for acute type A aortic dissection. METHODS: Data from the Tokyo Acute Aortic Super-network database spanning January 2015 to December 2017 were retrospectively reviewed. Pre- and postoperative factors related to early postoperative mortality were assessed in 1504 of 2058 (73.0%) consecutive patients [age: 66.6 (SD: 13.5) years, male: 52.9%] who underwent acute type A aortic dissection repair. RESULTS: The early mortality rate following surgical repair was 8.9%. According to multivariable analysis, male sex [odds ratio (OR) 1.670, 95% confidence interval (CI) 1.063-2.624, P = 0.026], use of percutaneous circulatory assist devices (n = 116, 7.7%) including extracorporeal membrane oxygenators or intra-aortic balloon pumps (OR 4.857, 95% CI 2.867-8.228, P < 0.001), shock (n = 162, 10.8%) (OR 3.06, 95% CI 1.741-5.387, P < 0.001), cardiopulmonary arrest (n = 41, 2.7%) (OR 7.534, 95% CI 3.407-16.661, P < 0.001), coronary ischaemia (n = 36, 2.3%) (OR 2.583, 95% CI 1.042-6.404, P = 0.041) and cerebral ischaemia (n = 59, 3.9%) (OR 2.904, 95% CI 1.347-6.261, P = 0.007) were independent preoperative risk factors for early mortality, while cardiac tamponade (n = 34, 2.3%) (OR 10.282, 95% CI 4.640-22.785, P < 0.001), cerebral ischaemia (n = 80, 5.3%) (OR 2.409, 95% CI 1.179-4.923, P = 0.016) and mesenteric ischaemia (n = 15, 1.0%) (OR 44.763, 95% CI 13.027-153.808, P < 0.001) were independent postoperative risk factors. CONCLUSIONS: Not only critical preoperative conditions but also postoperative cardiac tamponade and vital organ ischaemia are risk factors for early mortality after acute type A aortic dissection repair.

Nanoparticle Assembling Dynamics Induced by Pulsed Optical Force.

Femtosecond (fs) laser trapping dynamics is summarized for silica, hydrophobically modified silica, and polystyrene nanoparticles (NPs) in aqueous solution, highlighting their distinct optical trapping dynamics under CW laser. Mutually repulsive silica nanoparticles are tightly confined under fs laser compared to CW laser trapping and, upon increasing laser power, they are ejected from the focus as an assembly. Hydrophobically modified silica and polystyrene (PS) NPs are sequentially ejected just like a stream or ablated, giving bubbles. The ejection and bubbling take place with the direction perpendicular to laser polarization and its direction is randomly switched from one to the other. These characteristic features are interpreted from the viewpoint of single assembly formation of NPs at an asymmetric position in the optical potential. Temporal change in optical forces map is prepared for a single PS NP by calculating scattering, gradient, and temporal forces. The relative contribution of the forces changes with the volume increase of the assembly and, when the pushing force along the trapping pulse propagation overcome the gradient in the focal plane, the assembly undergoes the ejection. Further fs multiphoton absorption is induced for the larger assembly leading to bubble generation. The assembling, ejection, and bubbling dynamics of NPs are characteristic features of pulsed optical force and are considered as a new platform for developing new material fabrication method.

From Nanosecond Photochemistry to Optical Force Chemistry: My Journey.

Laser was invented in 1960 and soon introduced to chemistry research. We started time-resolved spectroscopy and photochemistry and initial trial was focused to nanosecond and then picosecond electronic absorption spectroscopy for studying molecular electronic excited states, charge separation in molecular complexes, and intermolecular electron transfer in solution. We considered that not only time-resolved but also space-resolved chemistry would be important for future laser-based chemistry and combined pulsed lasers with optical microscopes. Spectroscopy, photochemistry, ablation, and spatial arrangement of single microparticles and microdroplets in solution were carried out. Further we shifted from micro to nano and opened a new field covering spectroscopy, ablation, phase transition, crystallization, patterning, and fabrication. The progress is summarized and discussed as time-resolved nano spectroscopy, ablation nano dynamics, and optical force chemistry.

Optical Force-Induced Chemistry at Solution Surfaces.

When an intense 1,064-nm continuous-wave laser is tightly focused at solution surfaces, it exerts an optical force on molecules, polymers, and nanoparticles (NPs). Initially, molecules and NPs are gathered into a single assembly inside the focus, and the laser is scattered and propagated through the assembly. The expanded laser further traps them at the edge of the assembly, producing a single assembly much larger than the focus along the surface. Amino acids and inorganic ionic compounds undergo crystallization and crystal growth, polystyrene NPs form periodic arrays and disklike structures with concentric circles or hexagonal packing, and Au NPs demonstrate assembling and swarming, in which the NPs fluctuate like a group of bees. These phenomena that depend on laser polarization are called optically evolved assembling at solution surfaces, and their dynamics and mechanisms are elucidated in this review. As a promising application in materials science, the optical trapping assembly of lead halide perovskites, supramolecules, and aggregation-induced emission enhancement-active molecules is demonstrated and future directions for fundamental study are discussed.

Anomalously Large Assembly Formation of Polystyrene Nanoparticles by Optical Trapping at the Solution Surface.

We demonstrated the optical trapping-induced formation of a single large disc-like assembly (∼50 µm in diameter) of polystyrene (PS) nanoparticles (NPs) (100 nm in diameter) at a solution surface. Different from the conventional trapping behavior in solution, the assembly grows from the focus to the outside along the surface and contains needle structures expanding radially in all directions. Upon switching off the trapping laser, the assembly disperses and needle structures disappear, while the highly concentrated domain of the NPs is left for a while. The single assembly is quickly restored by switching on the laser again, where the needle structures are also reproduced but in a different way. When a single 10 µm PS microparticle (MP) is trapped in the NP solution, a single disc-like assembly containing needle structures is similarly prepared outside the MP. Based on backscattering imaging and tracking analyses of the MP at the solution surface, it is proposed that scattering and propagation of the trapping laser from the central part of the NP assembly or the MP lead to this new phenomenon.

Surface plasmon resonance effect on laser trapping and swarming of gold nanoparticles at an interface.

Laser trapping at an interface is a unique platform for aligning and assembling nanomaterials outside the focal spot. In our previous studies, Au nanoparticles form a dynamically evolved assembly outside the focus, leading to the formation of an antenna-like structure with their fluctuating swarms. Herein, we unravel the role of surface plasmon resonance on the swarming phenomena by tuning the trapping laser wavelength concerning the dipole mode for Au nanoparticles of different sizes. We clearly show that the swarm is formed when the laser wavelength is near to the resonance peak of the dipole mode together with an increase in the swarming area. The interpretation is well supported by the scattering spectra and the spatial light scattering profiles from single nanoparticle simulations. These findings indicate that whether the first trapped particle is resonant with trapping laser or not essentially determines the evolution of the swarming.

Fast-tracking of single emitters in large volumes with nanometer precision.

Multifocal plane microscopy allows for capturing images at different focal planes simultaneously. Using a proprietary prism which splits the emitted light into paths of different lengths, images at 8 different focal depths were obtained, covering a volume of 50x50x4 µm3. The position of single emitters was retrieved using a phasor-based approach across the different imaging planes, with better than 10 nm precision in the axial direction. We validated the accuracy of this approach by tracking fluorescent beads in 3D to calculate water viscosity. The fast acquisition rate (>100 fps) also enabled us to follow the capturing of 0.2 µm fluorescent beads into an optical trap.

Two-Year Results of a Multicenter Prospective Observational Study of the Zenith Spiral-Z Limb Deployed in the External Iliac Artery During Endovascular Aneurysm Repair.

BACKGROUND: Limited data is available on the use of a polyester graft limb with a helical stent configuration deployed in the external iliac artery (EIA) during endovascular aneurysm repair (EVAR), so we prospectively analyzed the efficacy of the Zenith Spiral-Z limb deployed in the EIA.Methods and Results:Patients undergoing EVAR using a Zenith stent-graft and Spiral-Z limb deployed in the EIA were prospectively registered in 24 Japanese institutions from June 2017 to November 2017. In total, 65 patients (74 limbs) (mean age: 77.1±8.0 years, 87.7% men, mean abdominal aortic aneurysm (AAA) diameter: 51.9±7.2 mm, mean iliac artery aneurysm (IAA) diameter: 38.3±10.0 mm) were registered and followed up. The most common reason for deployment in the EIA was a common IAA (43 limbs, 58.1%), and 8 limbs (10.8%) had a bare nitinol stent placed at the Spiral-Z limb. A total of 61 patients (70 limbs) completed a 24-month follow-up. There were 2 Spiral-Z limb stenoses and 1 occlusion, leading to a primary patency of 95.5% and a secondary patency of 100%, at 24 months. Buttock claudication occurred in 24.3% of the limbs treated at 1 month but decreased to 4.3% at 24 months. CONCLUSIONS: Our multicenter prospective study showed that Spiral-Z limb deployed in the EIA was associated with satisfactory results and seems to be a durable option, even in the era of iliac branch devices.

Large Submillimeter Assembly of Microparticles with Necklace-like Patterns Formed by Laser Trapping at Solution Surface.

In colloidal solution, nanoparticles can be optically trapped by a tightly focused laser beam, and they are assembled in a focal spot whose diameter is typically about one micrometer. We herein report that a large submillimeter sized assembly of polystyrene microparticles with necklace-like patterns are prepared by laser trapping at a solution surface. The light propagation outside the focal spot is directly confirmed by 1064 nm backscattering images, and finite difference time domain simulation well supports the idea that an optical potential is expanded outside the focal spot based on light propagation through whispering gallery mode. This demonstration opens a new method for fabrication of a millimeter-order huge assembly by a single tightly focused laser beam.

Photo-induced electrodeposition of metallic nanostructures on graphene.

Graphene, a single atomic layer of sp2 hybridized carbon, is a promising material for future devices due to its excellent optical and electrical properties. Nevertheless, for practical applications, it is essential to deposit patterned metals on graphene in the micro and nano-meter scale in order to inject electrodes or modify the 2D film electrical properties. However, conventional methods for depositing patterned metals such as lift-off or etching leave behind contamination. This contamination has been demonstrated to deteriorate the interesting properties of graphene such as its carrier mobility. Therefore, to fully exploit the unique properties of graphene, the controlled and nano-patterned deposition of metals on graphene films without the use of a sacrificial resist is of significant importance for graphene film functionalization and contact deposition. In this work, we demonstrate a practical and low-cost optical technique of direct deposition of metal nano-patterned structures without the need for a sacrificial lift-off resist. The technique relies on the laser induced reduction of metal ions on a graphene film. We demonstrate that this deposition is optically driven, and the resolution is limited only by the diffraction limit of the light source being used. Patterned metal features as small as 270 nm in diameter are deposited using light with a wavelength of 532 nm and a numerical aperture of 1.25. Deposition of different metals such as Au, Ag, Pd, Pb and Pt is shown. Additionally, change in the Fermi level of the graphene film through the nano-patterned metal is demonstrated through the electrical characterization of four probe field effect transistors.

The prognostic impact of the controlling nutritional status (CONUT) score in patients undergoing cardiovascular surgery.

BACKGROUND: Various postoperative predictive markers following cardiovascular surgery have been examined for use in the current aging population. The controlling nutritional status (CONUT) score, which is advocated not only as a screening tool for poor nutritional status, but also as an immunonutritional assessment, has started to attract attention in several clinical settings, such as in cancer and heart failure patients. The aim of this study was to evaluate the value of the CONUT score as a postoperative prognostic marker in patients who underwent cardiovascular surgery. METHODS: A total of 75 patients who underwent elective cardiovascular surgery between January 2015 and October 2017 were retrospectively analyzed. The patients were divided into two groups according to their preoperative CONUT score (i.e., CONUT < 2 or CONUT ≥ 2), and their clinicopathological characteristics, surgical outcomes, and overall survival were compared. The median follow-up period was 23 months (range 0-43 months) after surgery. RESULTS: The high CONUT group (CONUT ≥ 2), which consisted of 30 (40.0%) patients, had a significantly worse prognosis than the low CONUT group with regard to overall survival (p = 0.0007). On multivariate analyses, the CONUT score was identified as the only independent prognostic factor for overall survival (hazard ratio 1.47 per 1 CONUT score increase, 95% confidence interval 1.05-2.06, p < 0.026). CONCLUSIONS: The CONUT score is a reliable and independent preoperative predictor of overall survival after cardiovascular surgery.

Spatiotemporal Dynamics of Aggregation-Induced Emission Enhancement Controlled by Optical Manipulation.

We present spatiotemporal control of aggregation-induced emission enhancement (AIEE) of a protonated tetraphenylethene derivative by optical manipulation. A single submicrometer-sized aggregate is initially confined by laser irradiation when its fluorescence is hardly detectable. The continuous irradiation of the formed aggregate leads to sudden and rapid growth, resulting in bright yellow fluorescence emission. The fluorescence intensity at the peak wavelength of 540 nm is tremendously enhanced with growth, meaning that AIEE is activated by optical manipulation. Amazingly, the switching on/off of the activation of AIEE is arbitrarily controlled by alternating the laser power. This result means that optical manipulation increases the local concentration, which overcomes the electrostatic repulsion between the protonated molecules, namely, optical manipulation changes the aggregate structure. The dynamics and mechanism in AIEE controlled by optical manipulation will be discussed from the viewpoint of molecular conformation and association depending on the laser power.

[Cardiac Strangulation Induced by Epicardial Pacemaker Leads Causing Heart Failure;Report of a Case].

A 5-year-old girl has a history of epicardial VVI-pacemaker implantation due to congenital heart block at the age of 2 months. Five years later, she developed heart failure at the same time of battery depletion. The chest X-ray indicated the loop formation of the epicardial leads and the echocardiogram demonstrated paradoxical movement of ventricles. The 3-dimensional computed tomography finally revealed strangulation of biventricular apex caused by loop of the leads. She underwent reoperation. Cardiac strangulation was relieved by total removal of the loop and repositioning of right atrial and ventricular electrodes in a gentle curve of the leads. She was discharged and doing well. Cardiac strangulation is a rare, but it can be lethal. Therefore epicardial pacemaker leads should not be positioned around the ventricle with excessive redundancy.