Adaptive Optics Microscopy with Wavefront Sensing Based on Neighbor Correlation.

Complex structures in living cells and tissues induce wavefront errors when light waves pass through them, and images observed with optical microscopes are undesirably blurred. This problem is especially serious for living plant cells because images are strikingly degraded even within a single cell. Adaptive optics (AO) is expected to be a solution to this problem by correcting such wavefront errors, thus enabling high-resolution imaging. In particular, scene-based AO involves wavefront sensing based on the image correlation between subapertures in a Shack-Hartmann wavefront sensor and thus does not require an intense point light source. However, the complex 3D structures of living cells often cause low correlation between subimages, leading to loss of accuracy in wavefront sensing. This paper proposes a novel method for scene-based sensing using only image correlations between adjacent subapertures. The method can minimize changes between subimages to be correlated and thus prevent inaccuracy in phase estimation. Using an artificial test target mimicking the optical properties of a layer of living plant cells, an imaging performance with a Strehl ratio of approximately 0.5 was confirmed. Upon observation of chloroplast autofluorescence inside living leaf cells of the moss Physcomitrium patens, recovered resolution images were successfully obtained even with complex biological structures. Under bright-field illumination, the proposed method outperformed the conventional method, demonstrating the future potential of this method for label- and damage-free AO microscopy. Several points for improvement in terms of the effect of AO correction are discussed.

Reduction of converging distance change in an aquatic display formed with aerial imaging by retro-reflection in conjugated optical structure.

This paper proposes an optical system for aquatic display that shows an image in water. The aquatic image is formed by utilizing aerial imaging by retro-reflection, which converges light by a retro-reflector and a beam splitter. Refraction on intersection between air and another material causes spherical aberration, which changes light-converging distance. In order to reduce the converging distance change, the light-source component is filled with water so that the optical system becomes conjugate including the medium. We analyzed converging of light in water by simulations. Furthermore, we have confirmed effectiveness of conjugated optical structure experimentally by use of a prototype.

The Impact of Medical Students Teaching Basic Life Support to Laypersons.

Basic life support (BLS) courses for laypersons, including cardiopulmonary resuscitation (CPR) training, is known to improve outcomes of out-of-hospital cardiac events. We asked medical students to provide BLS training for laypersons as a part of their emergency medicine education and evaluated the effects of training on the BLS skills of laypersons. We also used a questionnaire to determine whether the medical students who provided the BLS training were themselves more confident and motivated to perform BLS compared to students who did not provide BLS training. The proportions of laypersons who reported confidence in checking for a response, performing chest compressions, and automated external defibrillator (AED) use were significantly increased after the BLS training. The proportions of medical students who reported increased confidence/motivation in terms of understanding BLS, checking for a response, chest compression, use of AED, and willingness to perform BLS were significantly greater among medical students who provided BLS instructions compared to those who did not. BLS instruction by medical students was associated with an improvement in laypersons' CPR accuracy and confidence in responding to cardiac arrest. The results indicate that medical students could gain understanding, confidence, and motivation in regard to their BLS skills by teaching BLS to laypersons.

Multicascade-linked synthetic-wavelength digital holography using a line-by-line spectral-shaped optical frequency comb.

Phase imaging without a phase wrapping ambiguity is required for wide-axial-range 3D imaging in the fields of surface topography measurement and biomedical imaging. Although multicascade-linked synthetic-wavelength digital holography (MCL-SW-DH) using an optical frequency synthesizer (OFS) is a promising method to meet this requirement, the slow switching of multiple optical wavelengths in the OFS prevents rapid imaging. In the work described in this article, a line-by-line spectral-shaped electro-optics-modulator-based optical frequency comb (EOM-OFC) is used as a light source in MCL-SW-DH to achieve rapid image acquisition. While MCL-SW-DH enables surface topography measurement with millimeter-order axial range and micrometer-order axial resolution, the line-by-line spectral-shaped EOM-OFC extracts a single narrow-linewidth OFC mode from the 10 GHz-spacing EOM-OFC at a center wavelength of 1545 nm within a spectral range of 30 nm at an interval of 500 ms. The effectiveness of the proposed MCL-SW-DH was highlighted by performing surface topography measurement with four step differences of sub-millimeter to millimeter size with an axial uncertainty of 2.08 µm in the image acquisition time of several seconds. The proposed MCL-SW-DH will be a powerful tool for 3D imaging with a wide axial range and high axial resolution.

Association between emergency medical service transport time and survival in patients with traumatic cardiac arrest: a Nationwide retrospective observational study.

BACKGROUND: Patients with traumatic cardiac arrest (TCA) are known to have poor prognoses. In 2003, the joint committee of the National Association of EMS Physicians and the American College of Surgeons Committee on Trauma proposed stopping unsuccessful cardiopulmonary resuscitation (CPR) sustained for > 15 min after TCA. However, in 2013, a specific time-limit for terminating resuscitation was dropped, due to the lack of conclusive studies or data. We aimed to define the association between emergency medical services transport time and survival to demonstrate the survival curve of TCA. METHODS: A retrospective review of the Japan Trauma Data Bank. Inclusion criteria were age ≥ 16, at least one trauma with Abbreviated Injury Scale score (AIS) ≥ 3, and CPR performed in a prehospital setting. Exclusion criteria were burn injury, AIS score of 6 in any region, and missing data. Estimated survival rate and risk ratio for survival were analyzed according to transport time for all patients. Analysis was also performed separately on patients with sustained TCA at arrival. RESULTS: Of 292,027 patients in the database, 5336 were included in the study with 4141 sustained TCA. Their median age was 53 years (interquartile range (IQR) 36-70), and 67.2% were male. Their median Injury Severity Score was 29 (IQR 22-41), and median transport time was 11 min (IQR 6-17). Overall survival after TCA was 4.5%; however, survival of patients with sustained TCA at arrival was only 1.2%. The estimated survival rate and risk ratio for sustained TCA rapidly decreased after 15 min of transport time, with estimated survival falling below 1%. CONCLUSION: The chances of survival for sustained TCA declined rapidly while the patient is transported with CPR support. Time should be one reasonable factor for considering termination of resuscitation in patients with sustained TCA, although clinical signs of life, and type and severity of trauma should be taken into account clinically.

Triple-views aerial display to show different floating images for surrounding directions.

To realize a triple-views aerial image floating in the center of the passages that can be displayed in front of an user and passed through, we propose a novel display device using aerial imaging with retro-reflection with polarization. We confirmed that our device can form aerial images in the center of the intersection of three passages and can display different contents to users in each passage without using the material as screen.

Aerial image resolution measurement based on the slanted knife edge method.

Image resolution is one of the most important performance specifications of aerial display techniques. However, there is no standard method for evaluating the aerial image resolution. In this paper, we propose a method for measuring the modulation transfer function (MTF) of an aerial imaging system based on the slanted knife edge method. We hypothesize that aerial images have a different blur function from standard camera images. In order to explore this, we simulate blurred slanted knife edge images by convolving two types of blur functions. Furthermore, the MTF curves of the aerial image formed using different retro-reflectors are compared using the proposed method.

Roadmap on 3D integral imaging: sensing, processing, and display.

This Roadmap article on three-dimensional integral imaging provides an overview of some of the research activities in the field of integral imaging. The article discusses various aspects of the field including sensing of 3D scenes, processing of captured information, and 3D display and visualization of information. The paper consists of a series of 15 sections from the experts presenting various aspects of the field on sensing, processing, displays, augmented reality, microscopy, object recognition, and other applications. Each section represents the vision of its author to describe the progress, potential, vision, and challenging issues in this field.

Luminal preloading with hydrogen-rich saline ameliorates ischemia-reperfusion injury following intestinal transplantation in rats.

Prolonged intestinal cold storage causes considerable mucosal breakdown, which could bolster bacterial translocation and cause life-threatening infection for the transplant recipient. The intestine has an intraluminal compartment, which could be a target for intervention, but has not yet been fully investigated. Hydrogen gas exerts organ protection and has used been recently in several clinical and basic research studies on topics including intestinal transplantation. In this study, we aimed to investigate the cytoprotective efficacy of intraluminally administered hydrogen-rich saline on cold IR injury in intestinal transplantation. Isogeneic intestinal transplantation with 6 hours of cold ischemia was performed on Lewis rats. Hydrogen-rich saline (H2 concentration at 5 ppm) or normal saline was intraluminally introduced immediately before preservation. Graft intestine was excised 3 hours after reperfusion and analyzed. Histopathological analysis of control grafts revealed blunting of the villi and erosion. These mucosal changes were notably attenuated by intraluminal hydrogen. Intestinal mucosa damage caused by IR injury led to considerable deterioration of gut barrier function 3 h post-reperfusion. However, this decline in permeability was critically prevented by hydrogen treatment. IR-induced upregulation of proinflammatory cytokine mRNAs such as IL-6 was mitigated by hydrogen treatment. Western blot revealed that hydrogen treatment regulated loss of the transmembrane protein ZO-1. Hydrogen-rich saline intraluminally administered in the graft intestine modulated IR injury to transplanted intestine in rats. Successful abrogation of intestinal IR injury with a novel strategy using intraluminal hydrogen may be easily clinically applicable and will compellingly improve patient care after transplantation.

Comparison of Two Different Intensive Care Unit Systems for Severely Ill Children in Japan: Data from the JaRPAC Registry.

The importance of centralizing treatment services for severely ill children has been well established, but such entralization remains difficult in Japan. We aimed to compare the trauma and illness severity and mortality of children admitted to two common types of ICUs for children. According to the type of management and disposition of the medical provider, we classified ICUs as pediatric ICUs [PICUs] or general ICUs, and analyzed differences in endogenous and exogenous illness settings between them. Overall, 1,333 pediatric patients were included, with 1,143 patients admitted to PICUs and 190 patients to general ICUs. The Pediatric Cerebral Performance Category score (PCPC) at discharge was significantly lower in the PICU group (adjusted OR: 0.45; 95%CI: 0.23-0.88). Death and unfavorable neurological outcomes occurred less often in the PICU group (adjusted OR: 0.29; 95%CI: 0.14-0.60). However, when limited to exogenous illness, PCPC scores (adjusted OR: 0.38; 95%CI: 0.07-1.99) or death/unfavorable outcomes (adjusted OR: 0.72; 95%CI: 0.08-6.34) did not differ between the groups. PCPC deterioration and overall sequelae/death rates were lower in PICUs for children with endogenous illnesses, although the outcomes of exogenous illness were similar between the 2 unit types. Further studies on the necessity of centralization are warranted.

Refractive index sensing with temperature compensation by a multimode-interference fiber-based optical frequency comb sensing cavity.

We proposed a refractive index (RI) sensing method with temperature compensation by using an optical frequency comb (OFC) sensing cavity including a multimode-interference (MMI) fiber, namely, the MMI-OFC sensing cavity. The MMI-OFC sensing cavity enables simultaneous measurement of material-dependent RI and sample temperature by decoding from the comb spacing frequency shift and the wavelength shift of the OFC. We realized the simultaneous and continuous measurement of RI-related concentration of a liquid sample and its temperature with precisions of 1.6 × 10-4 RIU and 0.08 °C. The proposed method would be a useful means for the various applications based on RI sensing.

Visualization of internal structure and internal stress in visibly opaque objects using full-field phase-shifting terahertz digital holography.

We construct a full-field phase-shifting terahertz digital holography (PS-THz-DH) system by use of a THz quantum cascade laser and an uncooled, 2D micro-bolometer array. The PS-THz-DH enables us to separate the necessary diffraction-order image from unnecessary diffraction-order images without the need for spatial Fourier filtering, leading to suppress the decrease of spatial resolution. 3D shape of a visibly opaque object is visualized with a sub-millimeter lateral resolution and a sub-µm axial resolution. Also, the digital focusing of amplitude image enables the visualization of internal structure with the millimeter-order axial selectivity. Furthermore, the internal stress distribution of an externally compressed object is visualized from the phase image. The demonstrated results imply a possibility for non-destructive inspection of visibly opaque non-metal materials.

Strain sensing based on strain to radio-frequency conversion of optical frequency comb.

We propose an optical frequency comb (OFC)-based strain sensing method, namely OFC sensing cavity, which is capable of radio-frequency (RF)-based strain measurement. We developed a null-method-based strain sensing system with a comb-spacing-stabilized OFC generator. We realized strain measurement from 1.83 µÎµ to 1800 µÎµ with a sensing fiber length of 20 mm. The measurable strain frequency range of the developed strain sensing system was from 0 to 310 Hz. Owing to the use of RF-based strain measurement, our approach would be a useful and powerful tool for sensing of strain or other physical quantities, and the concept of the OFC sensing cavity is a new aspect of OFC technology.

Refractive-index-sensing optical comb based on photonic radio-frequency conversion with intracavity multi-mode interference fiber sensor.

Optical frequency combs (OFCs) have attracted attention as optical frequency rulers due to their tooth-like discrete spectra together with their inherent mode-locking nature and phase-locking control to a frequency standard. Based on this concept, their applications until now have been demonstrated in the fields of optical frequency metrology. However, if the utility of OFCs can be further expanded beyond their application by exploiting new aspects of OFCs, this will lead to new developments in optical metrology and instrumentation. Here, we report a fiber sensing application of OFCs based on a coherent link between the optical and radio frequencies, enabling high-precision refractive index measurement based on frequency measurement in radio-frequency (RF) region. Our technique encodes a refractive index change of a liquid sample into a repetition frequency of OFC by a combination of an intracavity multi-mode-interference fiber sensor and wavelength dispersion of a cavity fiber. Then, the change in refractive index is read out by measuring the repetition frequency in RF region based on a frequency standard. Use of an OFC as a photonic RF converter will lead to the development of new applications in high-precision fiber sensing with the help of functional fiber sensors and precise RF measurement.

Multicascade-linked synthetic wavelength digital holography using an optical-comb-referenced frequency synthesizer.

Digital holography (DH) is a promising method for non-contact surface topography because the reconstructed phase image can visualize the nanometer unevenness in a sample. However, the axial range of this method is limited to the range of the optical wavelength due to the phase wrapping ambiguity. Although the use of two different wavelengths of light and the resulting synthetic wavelength, i.e., synthetic wavelength DH, can expand the axial range up to several hundreds of millimeters, its axial precision does not reach sub-micrometer. In this article, we constructed a tunable external cavity laser diode phase-locked to an optical frequency comb, namely, an optical-comb-referenced frequency synthesizer, enabling us to generate multiple synthetic wavelengths within the range of 32 µm to 1.20 m. A multiple cascade link of the phase images among an optical wavelength ( = 1.520 µm) and 5 different synthetic wavelengths ( = 32.39 µm, 99.98 µm, 400.0 µm, 1003 µm, and 4021 µm) enables the shape measurement of a reflective millimeter-sized stepped surface with the axial resolution of 34 nm. The axial dynamic range, defined as the ratio of the axial range ( = 2.0 mm) to the axial resolution ( = 34 nm), achieves 5.9 × 105, which is larger than that of previous synthetic wavelength DH. Such a wide axial dynamic range capability will further expand the application field of DH for large objects with meter dimensions.

Ictal Cardiorespiratory Arrest Associated with Status Epilepticus in Panayiotopoulos Syndrome.

A healthy 10-year-old boy vomited during sleep and later complained of abdominal pain; he became drowsy and uncommunicative. At the nearby hospital E.R., he deteriorated rapidly, and his respiratory movements were absent with cardiac arrest. He was immediately resuscitated. Brain MRI showed no abnormalities. EEG revealed an abnormal pattern with recurrent multifocal epileptiform activity over the bilateral occipital and frontal regions during sleep. Based on the clinical/radiological findings we diagnosed Panayiotopoulos syndrome (PS), a benign form of early-onset pediatric epilepsy characterized by autonomic symptoms. Lifethreating cardiopulmonary arrest is rare in PS, but long seizure duration of PS may associate with apnea and bradycardia.

Emphysematous cystitis successfully treated with hyperbaric oxygen therapy: case report.

Emphysematous cystitis is an uncommon acute infection of the underlying bladder musculature and mucosa, caused by gas-producing organisms. Here we describe an 87-year-old woman with diabetes mellitus and emphysematous cystitis who was successfully treated with hyperbaric oxygen (HBO2) therapy. Her predisposition of diabetes and infection with gas-producing bacteria was considered to precede the development of emphysematous cystitis. Computed tomography revealed gas accumulation in the bladder wall and lumen. Antibiotics and HBO2 therapy were administered. HBO2 therapy may be beneficial due to the improvement in oxygenation of the tissues affected by the disease. HBO2 is a useful adjunct therapy for the management of severe emphysematous cystitis.

Scan-less hyperspectral dual-comb single-pixel-imaging in both amplitude and phase.

We have developed a hyperspectral imaging scheme that involves a combination of dual-comb spectroscopy and Hadamard-transform-based single-pixel imaging. The scheme enables us to obtain 12,000 hyperspectral images of amplitude and phase at a spatial resolution of 46 µm without mechanical scanning. The spectral resolution given by the data point interval in the frequency domain is 20 MHz and the comb mode interval is 100 MHz over a spectral range of 1.2 THz centered at 191.5 THz. As an initial demonstration of our scheme, we obtained spectroscopic images of a standard test chart through an etalon plate. The thickness of an absorptive chromium-coated layer on a float-glass substrate was determined to be 70 nm from the hyperspectral phase images in the near-infrared wavelength region.

Occult Sources of Bleeding in Blunt Trauma : A Narrative Review.

Worldwide, hemorrhagic shock in major trauma remains a major potentially preventable cause of death. Controlling bleeding and subsequent coagulopathy is a big challenge. Immediate assessment of unidentified bleeding sources is essential in blunt trauma patients with hemorrhagic shock. Chest/pelvic X-ray in conjunction with ultrasonography have been established classically as initial diagnostic imaging modalities to identify the major sources of internal bleeding including intra-thoracic, intra-abdominal, or retroperitoneal hemorrhage related to pelvic fracture. Massive soft tissue injury, regardless of whether isolated or associated with multiple injuries, occasionally causes extensive hemorrhage and acute traumatic coagulopathy. Specific types of injuries, including soft tissue injury or retroperitoneal hemorrhage unrelated to pelvic fracture, can potentially be overlooked or be considered "occult" causes of bleeding because classical diagnostic imaging often cannot exclude such injuries. The purpose of this narrative review article is to describe "occult" or unusual sources of bleeding associated with blunt trauma.

Real-time absolute frequency measurement of continuous-wave terahertz radiation based on dual terahertz combs of photocarriers with different frequency spacings.

Real-time measurement of the absolute frequency of continuous-wave terahertz (CW-THz) radiation is required for characterization and frequency calibration of practical CW-THz sources. We proposed a method for real-time monitoring of the absolute frequency of CW-THz radiation involving temporally parallel, i.e., simultaneous, measurement of two pairs of beat frequencies and laser repetition frequencies based on dual THz combs of photocarriers (PC-THz combs) with different frequency spacings. To demonstrate the method, THz-comb-referenced spectrum analyzers were constructed with a dual configuration based on dual femtosecond lasers. Regardless of the presence or absence of frequency control in the PC-THz combs, a frequency precision of 10(-11) was achieved at a measurement rate of 100 Hz. Furthermore, large fluctuation of the CW-THz frequencies, crossing several modes of the PC-THz combs, was correctly monitored in real time. The proposed method will be a powerful tool for the research and development of practical CW-THz sources, and other applications.