Assessment of thirty-day readmission rate, timing, causes and predictors after hospitalization with COVID-19.

BACKGROUND: There are limited data on the characteristics of 30-day readmission after hospitalization with coronavirus disease 2019 (COVID-19). OBJECTIVES: To examine the rate, timing, causes, predictors and outcomes of 30-day readmission after COVID-19 hospitalization. METHODS: From 13 March to 9 April 2020, all patients hospitalized with COVID-19 and discharged alive were included in this retrospective observational study. Multivariable logistic regression was used to identify the predictors of 30-day readmission, and a restricted cubic spline function was utilized to assess the linearity of the association between continuous predictors and 30-day readmission. RESULTS: A total of 1062 patients were included in the analysis, with a median follow-up time of 62 days. The mean age of patients was 56.5 years, and 40.5% were women. At the end of the study, a total of 48 (4.5%) patients were readmitted within 30 days of discharge, and a median time to readmission was 5 days. The most common primary diagnosis of 30-day readmission was a hypoxic respiratory failure (68.8%) followed by thromboembolism (12.5%) and sepsis (6.3%). The patients with a peak serum creatinine level of ≥1.29 mg/dL during the index hospitalization, compared to those with a creatinine of <1.29 mg/dL, had 2.4 times increased risk of 30-day readmission (adjusted odds ratio: 2.41; 95% CI: 1.23-4.74). The mortality rate during the readmission was 22.9%. CONCLUSION: With 4.5% of the thirty-day readmission rate, COVID-19 survivors were readmitted early after hospital discharge, mainly due to morbidities of COVID-19. One in five readmitted COVID-19 survivors died during their readmission.

Search for Sub-eV Sterile Neutrinos at RENO.

We report a search result for a light sterile neutrino oscillation with roughly 2200 live days of data in the RENO experiment. The search is performed by electron antineutrino (ν[over ¯]_{e}) disappearance taking place between six 2.8 GW_{th} reactors and two identical detectors located at 294 m (near) and 1383 m (far) from the center of the reactor array. A spectral comparison between near and far detectors can explore reactor ν[over ¯]_{e} oscillations to a light sterile neutrino. An observed spectral difference is found to be consistent with that of the three-flavor oscillation model. This yields limits on sin^{2}2θ_{14} in the 10^{-4}≲|Δm_{41}^{2}|≲0.5 eV^{2} region, free from reactor ν[over ¯]_{e} flux and spectrum uncertainties. The RENO result provides the most stringent limits on sterile neutrino mixing at |Δm_{41}^{2}|≲0.002 eV^{2} using the ν[over ¯]_{e} disappearance channel.

Incidence, risk factors, and fracture healing of atypical femoral fractures: a multicenter case-control study.

The incidence of atypical femoral fractures (AFFs) was 2.95% among 6644 hip and femoral fractures. Independent risk factors included the use of bisphosphonates (BPs), osteopenia or osteoporosis, rheumatoid arthritis, increased femoral curvatures, and thicker femoral cortices. Patients with AFFs and BP treatment were more likely to have problematic healing than those with typical femoral fractures (TFFs) and no BP treatment. INTRODUCTION: To determine the incidence and risk factors of atypical femoral fractures (AFFs), we performed a multicenter case-control study. We also investigated the effects of bisphosphonates (BPs) on AFF healing. METHODS: We retrospectively reviewed the medical records and radiographs of 6644 hip and femoral fractures of patients from eight tertiary referral hospitals. All the radiographs were reviewed to distinguish AFFs from TFFs. Univariate and multivariate logistic regression analyses were performed to identify risk factors, and interaction analyses were used to investigate the effects of BPs on fracture healing. RESULTS: The incidence of AFFs among 6644 hip and femoral fractures was 2.95% (90 subtrochanter and 106 femoral shaft fractures). All patients were females with a mean age of 72 years, and 75.5% were exposed to BPs for an average duration of 5.2 years (range, 1-17 years). The use of BPs was significantly associated with AFFs (p < 0.001, odds ratio = 25.65; 95% confidence interval = 10.74-61.28). Other independent risk factors for AFFs included osteopenia or osteoporosis, rheumatoid arthritis, increased anterior and lateral femoral curvatures, and thicker lateral femoral cortex at the shaft level. Interaction analyses showed that patients with AFFs using BPs had a significantly higher risk of problematic fracture healing than those with TFFs and no BP treatment. CONCLUSIONS: The incidence of AFFs among 6644 hip and femoral fractures was 2.95%. Osteopenia or osteoporosis, use of BPs, rheumatoid arthritis, increased anterior and lateral femoral curvatures, and thicker lateral femoral cortex were independent risk factors for the development of AFFs. Patients with AFFs and BP treatment were more likely to have problematic fracture healing than those with TFFs and no BP treatment.

Assessing the cumulative impacts of geographically isolated wetlands on watershed hydrology using the SWAT model coupled with improved wetland modules.

Despite recognizing the importance of wetlands in the Coastal Plain of the Chesapeake Bay Watershed (CBW) in terms of ecosystem services, our understanding of wetland functions has mostly been limited to individual wetlands and overall catchment-scale wetland functions have rarely been investigated. This study is aimed at assessing the cumulative impacts of wetlands on watershed hydrology for an agricultural watershed within the Coastal Plain of the CBW using the Soil and Water Assessment Tool (SWAT). We employed two improved wetland modules for enhanced representation of physical processes and spatial distribution of riparian wetlands (RWs) and geographically isolated wetlands (GIWs). This study focused on GIWs as their hydrological impacts on watershed hydrology are poorly understood and GIWs are poorly protected. Multiple wetland scenarios were prepared by removing all or portions of the baseline GIW condition indicated by the U.S. Fish and Wildlife Service National Wetlands Inventory geospatial dataset. We further compared the impacts of GIWs and RWs on downstream flow (i.e., streamflow at the watershed outlet). Our simulation results showed that GIWs strongly influenced downstream flow by altering water transport mechanisms in upstream areas. Loss of all GIWs reduced both water routed to GIWs and water infiltrated into the soil through the bottom of GIWs, leading to an increase in surface runoff of 9% and a decrease in groundwater flow of 7% in upstream areas. These changes resulted in increased variability of downstream flow in response to extreme flow conditions. GIW loss also induced an increase in month to month variability of downstream flow and a decrease in the baseflow contribution to streamflow. Loss of all GIWs was shown to cause a greater fluctuation of downstream flow than loss of all RWs for this study site, due to a greater total water storage capacity of GIWs. Our findings indicate that GIWs play a significant role in controlling hydrological processes in upstream areas and downstream flow and, therefore, protecting GIWs is important for enhanced hydrological resilience to extreme flow conditions in this region.

Strain-Gradient Position Mapping of Semiconductor Quantum Dots.

We introduce a nondestructive method to determine the position of randomly distributed semiconductor quantum dots (QDs) integrated in a solid photonic structure. By setting the structure in an oscillating motion, we generate a large stress gradient across the QDs plane. We then exploit the fact that the QDs emission frequency is highly sensitive to the local material stress to map the position of QDs deeply embedded in a photonic wire antenna with an accuracy ranging from ±35 nm down to ±1 nm. In the context of fast developing quantum technologies, this technique can be generalized to different photonic nanostructures embedding any stress-sensitive quantum emitters.

Observation of Energy and Baseline Dependent Reactor Antineutrino Disappearance in the RENO Experiment.

The RENO experiment has analyzed about 500 live days of data to observe an energy dependent disappearance of reactor ν[over ¯]_{e} by comparing their prompt signal spectra measured in two identical near and far detectors. In the period between August of 2011 and January of 2013, the far (near) detector observed 31 541 (290 775) electron antineutrino candidate events with a background fraction of 4.9% (2.8%). The measured prompt spectra show an excess of reactor ν[over ¯]_{e} around 5 MeV relative to the prediction from a most commonly used model. A clear energy and baseline dependent disappearance of reactor ν[over ¯]_{e} is observed in the deficit of the observed number of ν[over ¯]_{e}. Based on the measured far-to-near ratio of prompt spectra, we obtain sin^{2}2θ_{13}=0.082±0.009(stat)±0.006(syst) and |Δm_{ee}^{2}|=[2.62_{-0.23}^{+0.21}(stat)_{-0.13}^{+0.12}(syst)]×10^{-3} eV^{2}.

An epidemiological study of androgenic alopecia in 3114 Korean patients.

BACKGROUND: Androgenetic alopecia (AGA) is the most common type of hair loss, and is characterized by the transformation of terminal scalp hair into vellus hair. The epidemiology of AGA is not fully understood. A strong genetic basis has long been identified, although little is known of its nongenetic causes. AIM: To evaluate the association of AGA with a number of environmental factors, including smoking, drinking and sleeping habit. METHODS: In total, 3114 Korean individuals with AGA who attended any one of 17 dermatology clinics in 6 cities in South Korea between March 2011 and February 2012 were enrolled in the study. Epidemiologic a data were collected using a standard questionnaire. RESULTS: No association was seen between eating or sleeping habits and severity of hair loss. However, drinking and smoking were associated with the severity of AGA in male patients. We also found that patients of both genders with a family history had more advanced types of hair loss, and the age of onset of AGA in male patients with a family history was earlier than that in male patients without a family history. CONCLUSIONS: Although the evidence for an environmental influence on AGA remains very weak, we did find an association between hair loss severity and certain environmental factors, such as smoking and drinking. Family history with more severe hair loss and an earlier age of onset.

Preclinical safety evaluation of subretinal AAV2.sFlt-1 in non-human primates.

We report on the long-term safety of AAV2.sFlt-1 (a recombinant adeno-associated virus serotype 2 carrying the soluble form of the Flt-1 receptor) injection into the subretinal space of non-human primates. Levels of sFlt-1 protein were significantly higher (P<0.05) in the vitreous of four out of five AAV2.sFlt-1-injected eyes. There was no evidence of damage to the eyes of animals that received subretinal injections of AAV2.sFlt-1; ocular examination showed no anterior chamber flare, normal fundus and electroretinography responses equivalent to those observed before treatment. Notably, immunological analysis demonstrated that gene therapy involving subretinal injection of AAV2.sFlt-1 does not elicit cell-mediated immunity. Biodistribution analysis showed that AAV2.sFlt-1 could be detected only in the eye and not in the other organs tested. These data indicate that gene therapy with subretinal AAV2.sFlt-1 is safe and well tolerated, and therefore promising for the long-term treatment of neovascular diseases of the eye.

Observation of reactor electron antineutrinos disappearance in the RENO experiment.

The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six 2.8 GW(th) reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is 0.920±0.009(stat)±0.014(syst). From this deficit, we determine sin(2)2θ(13)=0.113±0.013(stat)±0.019(syst) based on a rate-only analysis.

The 2019-2020 volcanic eruption of Late'iki (Metis Shoal), Tonga.

Late'iki (previously known as Metis Shoal) is a highly active volcano in the Tofua arc with at least four temporary island-building eruptions and one submarine eruption in the last 55 years. The most recent eruption, commencing in October 2019, resulted in lava effusion and subsequent phreatic explosions, the construction of a short-lived island that was quickly eroded by wave action and possibly further phreatic activity that continued into January 2020. The two-pyroxene dacite from the 2019 eruption is similar to the 1967/8 eruptions suggesting the magma is residual from earlier eruptions and has not undergone further differentiation in the last 50 years. New observations of the 2019 eruption site confirm the lava-dominant character of the volcano summit but a thin veneer of wave-reworked, finely fragmented lava material remains that is interpreted to have been produced by phreatic explosions from hot rock-water interactions during the effusive eruption. A notable absence of quench-fragmented hyaloclastite breccias suggests that non-explosive quench fragmentation processes were minimal at these shallow depths or that hyaloclastite debris has resedimented to greater depths beyond our summit survey area.

Causal mechanism of injection-induced earthquakes through the Mw 5.5 Pohang earthquake case study.

Causal mechanisms for fluid injection-induced earthquakes remain a challenge to identify. Past studies largely established spatiotemporal correlations. Here, we propose a multi-process causal mechanism for injection-induced earthquakes through a case study of the 2017 Mw 5.5 induced earthquake near Pohang Enhanced Geothermal System, Korea, where detailed hydraulic stimulation and on-site seismicity monitoring data provide an unprecedented opportunity. Pore pressure modeling reveals that pore pressure changes initiate seismicity on critically stressed faults and Coulomb static stress transfer modeling reveals that earthquake interactions promote continued seismicity, leading to larger events. On the basis of these results, we propose the following causal mechanism for induced seismicity: pore pressure increase and earthquake interactions lead to fault weakening and ultimately triggering larger earthquakes later in the process. We suggest that it is prudent that pore pressure change, initial seismicity locations, and Coulomb static stress transfer from seismicity earlier in the sequence are assessed in real-time.

In-hospital infective endocarditis following transcatheter aortic valve replacement: a cross-sectional study of the National Inpatient Sample database in the USA.

BACKGROUND: While the utilization of transcatheter aortic valve replacement (TAVR) for patients with severe aortic stenosis has been increasing, in-hospital infective endocarditis (IE) following TAVR has not been well described. AIM: To identify in-hospital IE following TAVR. METHODS: All patients who underwent TAVR between 2012 and 2014 were identified using the National Inpatient Sample database. Multi-variate logistic regression was performed to identify the predictors of in-hospital IE after TAVR. FINDINGS: Of the 41,025 patients who received TAVR, 120 patients (0.3%) developed in-hospital IE. Viridans group streptococci (20.8%) was the most frequent causative organism for in-hospital IE, followed by Staphylococcus aureus (16.7%) and enterococci (8.3%). Patients who developed in-hospital IE after TAVR had significantly higher rates of death (20.8% vs 4.1%, P<0.001), septic shock (16.7% vs 0.8%, P<0.001), cardiogenic shock (12.5% vs 3.4%, P=0.02), acute kidney injury requiring haemodialysis (16.7% vs 1.6%, P<0.001), bleeding requiring transfusion (29.2% vs 11.3%, P=0.01), myocardial infarction (12.5% vs 2.1%, P<0.001) and permanent pacemaker removal (4.2% vs 0.05%, P<0.001) compared with patients without IE. Independent predictors of in-hospital IE after TAVR include younger age [odds ratio (OR) 0.92, 95% confidence interval (CI) 0.89-0.95], drug abuse (OR 48.9, 95% CI 6.9-347.3) and human immunodeficiency virus (HIV) infection (OR 7.8, 95% CI 1.4-44.4). CONCLUSION: IE occurred in 0.3% of patients after TAVR during the same hospitalization, resulting in higher rates of adverse outcomes including mortality. Patients with younger age, a history of drug abuse or HIV infection are at greater risk of in-hospital IE following TAVR, and would benefit from vigilant preventive measures perioperatively.

Evaluation of abundance of artificial radionuclides in food products in South Korea and sources.

Food samples are collected nationwide from January 2016 to February 2017 and their contents of artificial radionuclides are measured to address the growing concerns regarding the radioactive contamination of food products in Korea. Specifically, 900 food samples are collected for this study and their contents of representative artificial radionuclides 134Cs, 137Cs, 239,240Pu, and 90Sr are analyzed. The analysis shows that the activity concentrations of 137Cs in fish range from minimum detectable activity (MDA) to 340 mBq/kg of fresh weight. The concentration factor (CF) determined for 137Cs as a measure of its bioavailability is calculated to be ca. 74 and found to be very similar to that (100) recommended by the International Atomic Energy Agency. With an MDA of <0.221 mBq/kg, the results reveal that 239,240Pu values in fish are below the MDA. The activity concentrations of 137Cs and 90Sr are lower than the MDA in both shellfish and seaweed, while the activity concentrations of 239,240Pu in shellfish range from 0.26 to 2.18 mBq/kg, and for seaweed samples range from 2.07 to 3.38 mBq/kg. The atom ratios of 240Pu/239Pu in shellfish caught at the Korean coast vary from 0.209 to 0.237, with a mean of 0.227. The higher 240Pu/239Pu atom ratio determined in shellfish is thought to be caused by the plutonium transported from the Pacific Proving Grounds rather than other sources such as the Fukushima nuclear power plant accident. The activity concentrations of 137Cs in mushrooms are found to vary from 1.0 to 21.4 Bq/kg, with the highest concentrations observed in the Oak (shiitake) and Sarcodon asparatus. 134Cs is detected in three mushroom specimens collected from Jeju Island and about 3-3.6% of 137Cs present in the wild mushrooms native to the Jeju Island are introduced as a result of the Fukushima nuclear plant accident. The annual effective doses of 137Cs received through consumption of mushrooms and fish are 2.0 × 10-4 mSv yr-1 and 3.9 × 10-5 mSv yr-1, and those values are negligible compared to the annual effective doses limit of 1 mSv yr-1.

Physical properties of new collimator cone system for stereotactic radiation therapy developed in samsung medical center.

PURPOSE: A new collimator cone system has been developed at the Samsung Medical Center that overcomes some of the limitations of present commercially supplied collimator cones. The physical properties of the newly developed cone system are described in this report. METHODS AND MATERIALS: The new cones have relatively larger aperture sizes (3.0-7.0 cm in diameter) and are 16 cm in length. Each new cone is fabricated with cerrobend alloy melted and poured into a stainless steel housing that is permanently fixed to a mounting plate. The mounting plate of the new cone is designed to insert into the wedge mount slot of the gantry head. The mechanical accuracy of the central axis of the cone pointing to the isocenter was tested using film, a steel ball positioned at the isocenter by the mechanical isocenter device. For the evaluation of beam flatness and penumbra, off-axis ratios at 5 cm depth were measured by film dosimetry using polystyrene phantom. RESULTS: The average error of the mechanical isocenter was 0.27 mm (+/- 0.16 mm). The beam flatness was excellent in the central region of the beam, and the average penumbra width was 3.35 mm (+/- 0.25 mm). The new cone design has more clearance between the patient's head and the gantry, and can more easily be removed from the gantry head because it slides in and out of the wedge slot. This facilitates changing cone sizes during one treatment session, and makes the process of double exposure port films easier. CONCLUSIONS: A new collimator cone system for stereotactic radiation therapy has been developed. The mechanical accuracy and physical properties are satisfactory for clinical use, and the new design permits a wider range of clinical applications for stereotactic radiation therapy.

A glass compensator filter to improve breast image quality in radiation therapy simulation.

PURPOSE: To improve the image quality of simulation films in tangential radiotherapy for breast cancer, we have designed a new compensator filter for the variation of breast contour using high-density-glass material. METHODS AND MATERIALS: The measurements and analyses of the body contour were done using CT scans, taken in the treatment position, of 20 breast cancer patients. The maximum tissue deficit that needed to be compensated for was 8 cm, and the authors fabricated the compensator system using high-density-glass material to maintain transparency. The glass compensator can be attached to the accessory mount of the simulator head and its position can be easily adjusted according to breast shape and position. The image qualities of simulation films taken with and without the glass compensator in tangential breast radiotherapy field were compared and the film densitometry was performed using the humanoid phantom. RESULTS: Using this compensator system, the overall image quality improved, resulting in enhanced contrast and resolution of the breast simulation image. The delineator wires for the beam margins were also well depicted, and the surgical clips within the breast tissue can be easily demonstrated. The film densitometry resulted in much less saturation over the breast tissue when using the glass compensator. CONCLUSION: Using the glass compensator system, the geographical miss may be reduced with the virtue of the improved image quality.

Fractionated stereotactic radiation therapy for extracranial head and neck tumors.

BACKGROUND: This study is to report the clinical experiences of fractionated stereotactic radiation therapy (FSRT) for extracranial head and neck tumors. METHODS AND MATERIALS: Between the period of July 1995 and November 1998, 48 patients with extracranial head and neck tumors were given FSRT as a boost and sole modality. Individualized treatment planning was performed using XKnife-3 system with relocatable Gill-Thomas-Cosman frame. In 24 patients, FSRT was applied as a boost technique following the 2-dimensional conventional external radiation therapy (ERT); in 24 patients FSRT was the sole radiotherapy modality. The primary diseases in the boost group consisted of nasopharynx cancer (19), lacrimal gland adenoid cystic carcinoma (3), orbital lymphoma (1), and skull-base recurrence of maxillary sinus adenoid cystic carcinoma (1). The primary diseases in the sole modality group consisted of recurrent nasopharynx cancer (12), orbital pseudotumor (4), skull-base recurrence of maxillary sinus, submandibular gland, and hypopharynx cancers (3), orbital rhabdomyosarcoma (2), orbital lymphoma (1), orbital metastasis of neuroblastoma (1), and nasal cavity melanoma (1). The fractionation schedule was to give 5 treatments per one week and the fractional doses were 2.0-3 Gy depending on the treatment aim and the FSRT volume. The FSRT doses varied depending on the nature of the primary diseases. RESULTS: The local tumor response in nasopharynx cancer patients was excellent compared to retrospective data without occurrence of unexpectedly severe complication. FSRT to other regions was well tolerated by the patients and resulted in good to excellent local tumor responses with no unacceptable side effects as expected by the authors. CONCLUSION: Based on the current observations, FSRT is a very effective and safe modality in the treatment of extracranial head and neck tumors.

Prompt radiation oncology record access by patient centered digital image chart system.

The authors have developed and evaluated a radiation oncology digital image chart system (RODICS). With this system we could achieve paperless and filmless practice, and thus improved operational efficiency within the department. In this paper, we describe characteristics and clinical usage of RODICS.

A filtration method for improving film dosimetry in photon radiation therapy.

Successful radiotherapy requires accurate dosimetry for treatment verification. Existing dosimeters such as ion chambers, TLD, and diodes have drawbacks such as relatively long measurement time and poor spatial resolution. These disadvantages become serious problems for dynamic-wedged beams. Thus the clinical use of dynamic wedges requires an improved dosimetry method. X-ray film may serve this purpose. However, x-ray film is not clinically accepted as a dosimeter for photon beams, because it overresponds to photons with energies below about 400 keV. This paper presents and develops a method which was initially proposed by Burch to improve the dose response of x-ray film in a phantom. The method is based on placing high-atomic number foils next to the film. The foils are used as filters to preferentially remove low-energy photons. The optimal film and filter configuration in a phantom was determined using a mathematical scheme derived in this study and a Monte Carlo technique (ITS code). The optimal configuration thus determined is as follows: the filter-to-film distance of 6 mm and the filter thickness of 0.15 mm for percent depth-dose measurement; the distance of 1 cm and the thickness of 0.25 mm for off-axis (dose) ratio measurement. The configuration was then tested with photon beams from a 4 MV linac. The test result indicates that the in-phantom dose distribution based on the optimal configuration agrees well with those measured by ion chambers.