Broadband Epsilon-Near-Zero Perfect Absorption in the Near-Infrared

Perfect absorption (PA) of incident light is important for both fundamental light-matter interaction studies and practical device applications. PA studies so far have mainly used resonant nanostructures that require delicate structural patterning. Here, we realize tunable and broadband PA in the near-infrared region using relatively simple thin film coatings. We adjust the growth condition of an ITO film and control its epsilon-near-zero (ENZ) wavelength. We show that this results in highly tunable PA in the telecommunication window. Then, using an ITO multilayer of different ENZ wavelengths, we demonstrate broadband PA that covers a wide range of near-infrared wavelengths. The use of ENZ coatings makes PA adjustable during the film growth and does not require any structural patterning afterward. It also facilitates the chip-scale integration of perfect absorbers with other device components. Broadband PA relaxes the single wavelength condition in previous PA studies, and thus it is suitable for many practical device applications, including sensors, photodetectors, and energy harvesting devicesopen0

Volume preservation of a shattered kidney after blunt trauma by superselective renal artery embolization

PURPOSEWe examined whether superselective embolization of the renal artery could be effectively employed to preserve traumatic kidneys and assessed its clinical outcomes.METHODSBetween December 2015 and November 2019, 26 patients who had American Association for the Surgery of Trauma grade V traumatic shattered kidneys were identified. Among them, a retrospective review was conducted of 16 patients who underwent superselective renal artery embolization for shattered kidney. The mean age was 41.2 ± 15.7 years, and the mean follow-up duration was 138.2 ± 140.1 days. Patient data including procedure details and clinical outcomes were reviewed, and the preserved volume of kidney parenchyma was calculated.RESULTSBleeding control was achieved in 13 (81%) patients and kidney preservation was achieved in 11 (79%). There was no mortality, and the median intensive care unit stay was 1.5 days. The mean volume of remnant kidney was 122.3 ± 66.0 cm3 (70%) on the last follow-up computed tomography. The estimated glomerular filtration rate was not significantly changed after superselective renal artery embolization.CONCLUSIONSuperselective renal artery embolization using a microcatheter for the shattered kidney effectively controlled hemorrhage in acute stage trauma and enabled kidney preservation

CRISPR/Cas9-induced knockout and knock-in mutations in Chlamydomonas reinhardtii

Genome editing is crucial for genetic engineering of organisms for improved traits, particularly in microalgae due to the urgent necessity for the next generation biofuel production. The most advanced CRISPR/Cas9 system is simple, efficient and accurate in some organisms; however, it has proven extremely difficult in microalgae including the model alga Chlamydomonas. We solved this problem by delivering Cas9 ribonucleoproteins (RNPs) comprising the Cas9 protein and sgRNAs to avoid cytotoxicity and off-targeting associated with vector-driven expression of Cas9. We obtained CRISPR/Cas9-induced mutations at three loci including MAA7, CpSRP43 and ChlM, and targeted mutagenic efficiency was improved up to 100 fold compared to the first report of transgenic Cas9-induced mutagenesis. Interestingly, we found that unrelated vectors used for the selection purpose were predominantly integrated at the Cas9 cut site, indicative of NHEJ-mediated knock-in events. As expected with Cas9 RNPs, no off-targeting was found in one of the mutagenic screens. In conclusion, we improved the knockout efficiency by using Cas9 RNPs, which opens great opportunities not only for biological research but also industrial applications in Chlamydomonas and other microalgae. Findings of the NHEJ-mediated knock-in events will allow applications of the CRISPR/Cas9 system in microalgae, including safe harboring techniques shown in other organisms.

CRISPR/Cas9-induced knockout and knock-in mutations in Chlamydomonas reinhardtii

Genome editing is crucial for genetic engineering of organisms for improved traits, particularly in microalgae due to the urgent necessity for the next generation biofuel production. The most advanced CRISPR/Cas9 system is simple, efficient and accurate in some organisms; however, it has proven extremely difficult in microalgae including the model alga Chlamydomonas. We solved this problem by delivering Cas9 ribonucleoproteins (RNPs) comprising the Cas9 protein and sgRNAs to avoid cytotoxicity and off-targeting associated with vector-driven expression of Cas9. We obtained CRISPR/Cas9-induced mutations at three loci including MAA7, CpSRP43 and ChlM, and targeted mutagenic efficiency was improved up to 100 fold compared to the first report of transgenic Cas9-induced mutagenesis. Interestingly, we found that unrelated vectors used for the selection purpose were predominantly integrated at the Cas9 cut site, indicative of NHEJ-mediated knock-in events. As expected with Cas9 RNPs, no off-targeting was found in one of the mutagenic screens. In conclusion, we improved the knockout efficiency by using Cas9 RNPs, which opens great opportunities not only for biological research but also industrial applications in Chlamydomonas and other microalgae. Findings of the NHEJ-mediated knock-in events will allow applications of the CRISPR/Cas9 system in microalgae, including "safe harboring" techniques shown in other organisms142561sciescopu

Optical thin films prepared by ion-assisted and ultrasound-assisted deposition.

Optical, electrical, and microstructural effects of Ar ion bombardment and Ar incorporation on thermally evaporated Ag and Al thin films were investigated. The results show that as the momentum supplied to the growing films by the bombarding Ar ions per arriving metal atom increases, refractive index at 632.8 nm increases and extinction coefficient decreases, lattice spacing expands, grain size decreases, electrical resistivity increases, and trapped Ar increases slightly. In Ag films, stress reverses from tensile to compressive; in AI films compressive stress increases. In both films, the change in optical constants can be explained by variation in void volume. The reversal of stress from tensile to compressive in Ag films requires a threshold level of momentum. The increase in electrical resistivity is related to the increase in the void fraction, decrease in the grain size, and increase in trapped Ar in both types of films. Many of these properties correlate well with the momentum transferred, suggesting that the momentum is an important physical parameter in describing the influence of ion beams on growing thin films and determining the characteristics of thin metal films prepared by ion-assisted deposition (IAD). With a low energy ion beam, the Ar concentration in IAD Ag films was negligible. When the bombarded film thickness was less than 5 nm, the electrical resistivity of IAD Ag films tended to decrease slightly from that of the non-IAD film. Using the Bruggeman effective medium theory, a formula for the void fraction at any given wavelength was derived. We investigated optical properties, stoichiometry, chemical bonding states, and structure of aluminum oxynitride thin films prepared by reactive ion-assisted deposition. Variations of optical constants and chemical bonding states are related to the stoichiometry. We found that our amorphous aluminum oxynitride film is not simply a mixture of aluminum oxide and nitride but a compound. A rugate filter using a step-index profile of aluminum oxynitride films was fabricated by nitrogen ion beam bombardment of a growing Al film with backfilled oxygen pressure as the sole variable. The effects of ultrasound-assisted deposition (UAD) on the optical properties of ZrO₂, Ta₂O₅, and MgF₂ films were investigated. UAD is likely to induce oxygen and fluoride deficiencies in oxide and fluoride films and increase the packing density of films

OPTICAL AND STRUCTURAL PROPERTIES OF OPTICAL THIN FILMS WITH VARIOUS COLUMNAR MICROSTRUCTURES

In this study, optical and structural properties of the thin films prepared using glancing angle deposition (GLAD) are investigated. Various glancing angles and substrate rotations are employed to control the columnar microstructure of the films. The results show that as the glancing angle increases, the column angle and the porosity of TiO2 films increase and the refractive index decreases, due to shadow effects. The optical anisotropy of tilted and zigzag microstructure TiO2 films have a large anisotropy and reaches a maximum at a glancing angle of 60°, while that of helical microstructure TiO2 film deposited at 60° with substrate rotation shows a very small anisotropy due to the symmetric structure. It is found that the optical anisotropy of TiO2 films deposited by GLAD can be controlled by modification of microstructure

Intervention for Chest Trauma and Large Vessel Injury

Trauma is an injury to the body that involves multiple anatomical and pathophysiological changes caused by forces acting from outside the body. The number of patients with trauma is increasing as our society becomes more sophisticated. The importance and demand of traumatology are growing due to the development and spread of treatment and diagnostic technologies. In particular, damage to the large blood vessels of the chest can be life-threatening, and the sequelae are often severe; therefore, diagnostic and therapeutic methods are becoming increasingly important. Trauma to nonaortic vessels of the thorax and aorta results in varying degrees of physical damage depending on the mechanism of the accident and anatomical damage involved. The main damage is hemorrhage from non-aortic vessels of the thorax and aorta, accompanied by hemodynamic instability and coagulation disorders, which can be life-threatening. Immediate diagnosis and rapid therapeutic access can often improve the prognosis. The treatment of trauma can be surgical or interventional, depending on the patient’s condition. Among them, interventional procedures are increasingly gaining popularity owing to their convenience, rapidity, and high therapeutic effectiveness, with increasing use in more trauma centers worldwide. Typical interventional procedures for patients with thoracic trauma include embolization for non-aortic injuries and thoracic endovascular aortic repair for aortic injuries. These procedures have many advantages over surgical treatments, such as fewer internal or surgical side effects, and can be performed more quickly than surgical procedures, contributing to improved outcomes for patients with trauma

Admittance matching analysis of perfect absorption in unpatterned thin films

We perform a detailed analysis of perfect absorption in unpattemed thin films by invoking admittance matching conditions. We consider a single, absorptive layer coated on a reflective substrate and investigate perfect absorption conditions for normal and oblique incidences of light. For normal incidence, it is found that we need larger optical losses as the film gets thinner. But, for oblique incidence, perfect absorption can be achieved even for very small losses especially around the epsilonnear-zero frequency of the film. We consider the oblique incidence case in two different configurations (termed Berreman and ATR configurations). In both cases, we show that perfect absorption involves critical coupling to TM modes existing in thin films. We also evaluate actual light absorption and the electric field distribution in ITO films using the transfer matrix method, and show that it agrees well with our analytic theory. Finally, we present a versatile diagram that visualizes the admittance matching process in thin film structures. Our work presents an in-depth analysis of light absorption in thin films and provides design principles for various thin film devices, such as sensors, optical filters, optical modulators, and thermal emitters. (C) 2014 Elsevier B.V. All rights reservedclose5

Control of resonant wavelength from organic light-emitting materials by use of a Fabry-Perot microcavity structure

We report the fabrication of Fabry–Perot microcavity structures with the organic light-emitting material tris- 8-hydroxyquinoline aluminum Alq3 and derive their optical properties by measuring their photoluminescence PL and absorption. Silver and a TiO2–SiO2 multilayer were used as metal and dielectric reflectors, respectively, in a Fabry–Perot microcavity structure. Three types of microcavity were prepared: type A consisted of air Ag Alq3 Ag glass ; type B, of air dielectric Alq3 dielectric glass ; and type C, of air Ag Alq3 dielectric glass . A bare Alq3 film of air Alq3 glass had its PL peak near 514 nm, and its full width at half-maximum FWHM was 80 nm. The broad FWHM of a bare Alq3 film was reduced to 15–27.5, 7–10.5, and 16–16.6 nm for microcavity types A, B, and C, respectively. Also, we could control the PL peak of the microcavity structure by changing the spacer thickness, the amount of phase change on reflection, and the angle of incidence.This research was supported by Korea Research Foundation grant KRF-2000-015-DP0174