Detailed knowledge of the image of the point spread function (PSF) is necessary to optimize astronomical coronagraph masks and to understand potential sources of errors in astrometric measurements. ...The PSF for astronomical telescopes and instruments depends not only on geometric aberrations and scalar wave diffraction but also on those wavefront errors introduced by the physical optics and the polarization properties of reflecting and transmitting surfaces within the optical system. These vector wave aberrations, called polarization aberrations, result from two sources: (1) the mirror coatings necessary to make the highly reflecting mirror surfaces, and (2) the optical prescription with its inevitable non-normal incidence of rays on reflecting surfaces. The purpose of this article is to characterize the importance of polarization aberrations, to describe the analytical tools to calculate the PSF image, and to provide the background to understand how astronomical image data may be affected. To show the order of magnitude of the effects of polarization aberrations on astronomical images, a generic astronomical telescope configuration is analyzed here by modeling a fast Cassegrain telescope followed by a single 90° deviation fold mirror. All mirrors in this example use bare aluminum reflective coatings and the illumination wavelength is 800 nm. Our findings for this example telescope are: (1) The image plane irradiance distribution is the linear superposition of four PSF images: one for each of the two orthogonal polarizations and one for each of two cross-coupled polarization terms. (2) The PSF image is brighter by 9% for one polarization component compared to its orthogonal state. (3) The PSF images for two orthogonal linearly polarization components are shifted with respect to each other, causing the PSF image for unpolarized point sources to become slightly elongated (elliptical) with a centroid separation of about 0.6 mas. This is important for both astrometry and coronagraph applications. (4) Part of the aberration is a polarization-dependent astigmatism, with a magnitude of 22 milliwaves, which enlarges the PSF image. (5) The orthogonally polarized components of unpolarized sources contain different wavefront aberrations, which differ by approximately 32 milliwaves. This implies that a wavefront correction system cannot optimally correct the aberrations for all polarizations simultaneously. (6) The polarization aberrations couple small parts of each polarization component of the light (∼10-4) into the orthogonal polarization where these components cause highly distorted secondary, or "ghost" PSF images. (7) The radius of the spatial extent of the 90% encircled energy of these two ghost PSF image is twice as large as the radius of the Airy diffraction pattern. Coronagraphs for terrestrial exoplanet science are expected to image objects 10-10, or 6 orders of magnitude less than the intensity of the instrument-induced "ghost" PSF image, which will interfere with exoplanet measurements. A polarization aberration expansion which approximates the Jones pupil of the example telescope in six polarization terms is presented in the appendix. Individual terms can be associated with particular polarization defects. The dependence of these terms on angles of incidence, numerical aperture, and the Taylor series representation of the Fresnel equations lead to algebraic relations between these parameters and the scaling of the polarization aberrations. These "design rules" applicable to the example telescope are collected in § 5. Currently, exoplanet coronagraph masks are designed and optimized for scalar diffraction in optical systems. Radiation from the "ghost" PSF image leaks around currently designed image plane masks. Here, we show a vector-wave or polarization optimization is recommended. These effects follow from a natural description of the optical system in terms of the Jones matrices associated with each ray path of interest. The importance of these effects varies by orders of magnitude between different optical systems, depending on the optical design and coatings selected. Some of these effects can be calibrated while others are more problematic. Polarization aberration mitigation methods and technologies to minimize these effects are discussed. These effects have important implications for high-contrast imaging, coronagraphy, and astrometry with their stringent PSF image symmetry and scattered light requirements.
Patients with severe kidney diseases are at risk of complications from COVID-19; however, little is known about the effectiveness of COVID-19 vaccines in children and adolescents with kidney ...diseases.
We investigated the immunogenicity and safety of an accelerated 3-dose primary series of COVID-19 vaccination among 59 pediatric patients with chronic kidney disease (CKD) (mean age 12.9 years; 30 male) with or without immunosuppression, dialysis, or kidney transplant. Dosage was 0.1 ml BNT162b2 to those aged 5 to 11 years, and 0.3 ml BNT162b2 to those aged 11 to 18 years.
Three doses of either vaccine type elicited significant antibody responses that included spike receptor-binding domain (S-RBD) IgG (90.5%–93.8% seropositive) and surrogate virus neutralization (geometric mean sVNT% level, 78.6%–79.3%). There were notable T cell responses. Weaker neutralization responses were observed among those on immunosuppression, especially those receiving higher number of immunosuppressants or on mycophenolate mofetil. Neutralization was reduced against Omicron BA.1 compared to wild type (WT, i.e., ancestral) (post-dose 3 sVNT% level; 82.7% vs. 27.4%; P < 0.0001). However, the T cell response against Omicron BA.1 was preserved, which likely confers protection against severe COVID-19. Infected patients exhibited hybrid immunity after vaccination, as evidenced by the higher Omicron BA.1 neutralization response among these infected patients who received 2 doses compared with those who were uninfected. Generally mild or moderate adverse reactions following vaccines were reported.
An accelerated 3-dose primary series with BNT162b2 is immunogenic and safe in young children and adolescents with kidney diseases.
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Background and Aims
There are no prospective data on stereotactic body radiation therapy (SBRT) as a bridge to liver transplantation for HCC. This study aimed to evaluate the efficacy and safety of ...SBRT as bridging therapy, with comparison with transarterial chemoembolization (TACE) and high‐intensity focused ultrasound (HIFU).
Approach and Results
Patients were prospectively enrolled for SBRT under a standardized protocol from July 2015 and compared with a retrospective cohort of patients who underwent TACE or HIFU from 2010. The primary endpoint was tumor control rate at 1 year after bridging therapy. Secondary endpoints included cumulative incidence of dropout, toxicity, and posttransplant survival.
During the study period, 150 patients were evaluated (SBRT, n = 40; TACE, n = 59; HIFU, n = 51). The tumor control rate at 1 year was significantly higher after SBRT compared with TACE and HIFU (92.3%, 43.5%, and 33.3%, respectively; P = 0.02). With competing risk analysis, the cumulative incidence of dropout at 1 and 3 years after listing was lower after SBRT (15.1% and 23.3%) compared with TACE (28.9% and 45.8%; P = 0.034) and HIFU (33.3% and 45.1%; P = 0.032). Time‐to‐progression at 1 and 3 years was also superior after SBRT (10.8%, 18.5% in SBRT, 45%, 54.9% in TACE, and 47.6%, 62.8% in HIFU; P < 0.001). The periprocedural toxicity was similar, without any difference in perioperative complications and patient and recurrence‐free survival rates after transplant. Pathological complete response was more frequent after SBRT compared with TACE and HIFU (48.1% vs. 25% vs. 17.9%, respectively; P = 0.037). In multivariable analysis, tumor size <3 cm, listing alpha‐fetoprotein <200 ng/mL, Child A, and SBRT significantly reduced the risk of dropout.
Conclusions
SBRT was safe, with a significantly higher tumor control rate, reduced the risk of waitlist dropout, and should be used as an alternative to conventional bridging therapies.
The proper use of face mask comprises the correct practice and wearing technique and is important in preventing the spread of respiratory infections. Previous studies have addressed only the aspect ...of practice and failed to provide a detailed account of face mask usage amongst community-based populations. This study examined the practice and technique of using face mask amongst adults.
A cross-sectional descriptive design was adopted. A quota sample of 1500 adults was recruited in Hong Kong during a nonepidemic state between January and February 2017. The participants' practice of using face mask in five given situations was assessed using a questionnaire. Their technique in using face mask, including 12 steps, was assessed using an observation checklist. Statistical tests were used to compare the differences in practice and technique amongst adults of different gender and age groups.
Findings revealed that the performance of the participants in both categories was unsatisfactory. In terms of practice, less than one-fifth of the participants reported that they always wore face mask when taking care of family members with fever (14.7%) or respiratory infections (19.5%). Male adults and those aged 55-64 reported low frequency in using face mask during required situations. In terms of technique, none of the participants performed all the required steps in using face mask correctly. More than 90% of the participants did not perform hand hygiene before putting on (91.5%), taking off (97.3%), or after disposing (91.5%) face mask. Adults aged 55 and above performed poorer than adults in the younger age groups.
Compared with previous findings obtained during an epidemic, the performance of the participants during a nonepidemic state was less satisfactory. The possibility of developing fatigue after exposure to repeated epidemics was discussed. This study contributes to a comprehensive understanding of the use of face mask in a community and reveals the underperformed areas. Effort is required to enhance the proper practice of using face mask, convey the message that hand hygiene is an essential step in wearing and taking off a face mask and increase the public's general concern in the value of using face mask.
•Fundamental properties of copper(I) complexes.•Copper complexes for organic light-emitting diodes.•Copper complexes for dye-sensitized solar cells.•Copper complexes for bulk heterojunction solar ...cells.
A great deal of research effort has been put in green energy applications in the past few decades based on organic optoelectronics. Compared with conventional inorganic semiconductors, organic counterparts offer a much simpler strategy for low-cost mass production and structural modification. Hence, continuous and intensive academic and industrial research works have been done in these areas. In terms of the materials used, transition-metal complexes with the unique features of the transition metal centers represent a large group of candidates, showing high performance in energy conversion technologies. However, the commonly used transition metals, like Pt(II), Ir(III) and Ru(II), are expensive and of relatively low abundance. Concerning elemental sustainability and marketability, some abundant and cheaper metals should be investigated and further developed to replace these precious metals. Cu(I) complexes have shown their potentiality in solar energy harvesting and light emitting applications, due to their well-studied photophysics and structural diversity. In addition, copper is one of the earth-abundant metals with less toxicity, which makes it competitive to precious transition metals. As a result, a series of rational molecular engineering has been developed to boost the device performance of copper complexes. In this review, the recent progress of copper complexes in the fields of organic light emitting devices (OLEDs), photovoltaic cells (dye-sensitized solar cells (DSSCs) and bulk heterojunction solar cells (BHJSCs)) in the past two decades will be presented. Representative examples are chosen for discussion.
Weak light absorption of common Ir(III) complexes (e. g., using phenylpyridine as the ligand) has hindered their applications in photocatalytic hydrogen generation from water as an efficient ...photosensitizer. To address this issue, a series of cyclometalated Ir(III) complexes (Ir1–Ir5), featuring different electron‐donating substituents to enhance the absorptivity, have been synthesized and studied as photosensitizers (PSs) for light‐driven hydrogen production from water. Ir6–Ir7 were prepared as fundamental systems for comparisons. Electron donors, including 9‐phenylcarbazole, triphenylamine, 4,4′‐dimethoxytriphenylamine, 4,4′‐di(N‐hexylcarbazole)triphenylamine moieties were introduced on 6‐(thiophen‐2‐yl)phenanthridine‐based cyclometalating (C^N) ligands to explore the donor effect on the hydrogen evolution performance of these cationic Ir(III) complexes. Remarkably, Ir4 with 4,4′‐dimethoxytriphenylamine achieved the highest turn‐over number (TON) of 12 300 and initial turnover frequency (TOFi) of 394 h−1, with initial activity (activityi) of 547 000 μmol g−1 h−1 and initial apparent quantum yield (AQYi) of 9.59 %, under the illumination of blue light‐emitting diodes (LEDs) for 105 hours, which demonstrated a stable three‐component photocatalytic system with high efficiency. The TON (based on n(H2)/n(PSr)) in this study is the highest value reported to date among the similar photocatalytic systems using Ir(III) complexes with Pt nanoparticles as catalyst. The great potential of using triphenylamine‐based Ir(III) PSs in boosting photocatalytic performance has also been shown.
Intense and broadband UV‐Vis absorption do matters in iridium(III)‐based photosensitizers for photocatalytic hydrogen generation. This study reveals the importance of choosing an appropriate electron donor on the C^N ligands to improve the performance. The use of triphenylamine‐based Ir(III) PSs shows great potential in boosting the photocatalytic performance.
A series of neutral cyclometalated platinum(II) complexes bearing 2,6‐bis(2‐naphthyl)pyridine as a C^N^C tridentate chelating ligand with monodentate pyridyl ligands with different substituents 1–3 ...have been synthesized via double cyclometalation and ligand displacement reaction. The structural, photophysical, electrochemical and aggregation induced emission (AIE) properties of these neutral platinum(II) complexes were systematically studied. Complexes 1–3 exhibited AIE effects with different emission intensities and colors, in which 1 showed the highest quantum efficiency of 8.6 % under aggregated state, and the aggregates were assembled to ordered spheres. Among the Pt(II) complexes, 1 showed a bactericidal activity against both Staphylococcus aureus (S. aureus) (MIC and MBC=3.13 μg/mL) and methicillin‐resistant S. aureus (MRSA) (MIC and MBC=6.25 μg/mL). Complex 1 did not possess noticeable cytotoxicity to human skin HaCaT keratinocytes. The non‐cytotoxic complex 1 would have a good potential to be used for the antibacterial therapy to combat with S. aureus and MRSA‐infected skin diseases.
A series of tridentate cyclometalated platinum(II) complexes were synthesized. They showed aggregation induced emission behaviors. Complex 1 showed a bactericidal activity against both Staphylococcus aureus (S. aureus) (MIC and MBC=3.13 μg/mL) and methicillin‐resistant S. aureus (MIC and MBC=6.25 μg/mL) and did not possess noticeable cytotoxicity to human skin HaCaT keratinocytes.
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