Improving Neural Radiance Field using Near-Surface Sampling with Point Cloud Generation

Neural radiance field (NeRF) is an emerging view synthesis method that samples points in a three-dimensional (3D) space and estimates their existence and color probabilities. The disadvantage of NeRF is that it requires a long training time since it samples many 3D points. In addition, if one samples points from occluded regions or in the space where an object is unlikely to exist, the rendering quality of NeRF can be degraded. These issues can be solved by estimating the geometry of 3D scene. This paper proposes a near-surface sampling framework to improve the rendering quality of NeRF. To this end, the proposed method estimates the surface of a 3D object using depth images of the training set and sampling is performed around there only. To obtain depth information on a novel view, the paper proposes a 3D point cloud generation method and a simple refining method for projected depth from a point cloud. Experimental results show that the proposed near-surface sampling NeRF framework can significantly improve the rendering quality, compared to the original NeRF and a state-of-the-art depth-based NeRF method. In addition, one can significantly accelerate the training time of a NeRF model with the proposed near-surface sampling framework.Comment: 13 figures, 2 table

Cell type–dependent variation in paracrine potency determines therapeutic efficacy against neonatal hyperoxic lung injury

AbstractBackground aimsThe aim of this study was to determine the optimal cell type for transplantation to protect against neonatal hyperoxic lung injury. To this end, the in vitro and in vivo therapeutic efficacies and paracrine potencies of human umbilical cord blood–derived mesenchymal stromal cells (HUMs), human adipose tissue–derived mesenchymal stromal cells (HAMs) and human umbilical cord blood mononuclear cells (HMNs) were compared.MethodsHyperoxic injury was induced in vitro in A549 cells by challenge with H2O2. Alternatively, hyperoxic injury was induced in newborn Sprague-Dawley rats in vivo by exposure to hyperoxia (90% oxygen) for 14 days. HUMs, HAMs or HMNs (5 × 105 cells) were given intratracheally at postnatal day 5.ResultsHyperoxia-induced increases in in vitro cell death and in vivo impaired alveolarization were significantly attenuated in both the HUM and HAM groups but not in the HMN group. Hyperoxia impaired angiogenesis, increased the cell death and pulmonary macrophages and elevated inflammatory cytokine levels. These effects were significantly decreased in the HUM group but not in the HAM or HMN groups. The levels of human vascular endothelial growth factor and hepatocyte growth factor produced by donor cells were highest in HUM group, followed by HAM group and then HMN group.ConclusionsHUMs exhibited the best therapeutic efficacy and paracrine potency than HAMs or HMNs in protecting against neonatal hyperoxic lung injury. These cell type-dependent variations in therapeutic efficacy might be associated or mediated with the paracrine potency of the transplanted donor cells

Weighted-Averaging Finite-Element Method for Scalar Wave Equation in the Frequency Domain

We develop a new weighted-averaging finite-element method which can be applied to generate synthetic seismograms using scalar wave equation in the frequency domain. Our method introducest hree kinds of supplementarye lements etsi n addition to a basic elements et which is used in standard finite-element method. By constructing global stiffness and mass matrices for four kinds of element sets and then averaging them with weighting coefficients, we obtain a,new global stiffness and mass matrix. With the optimal weighting coefficients minimizing grid dispersion and grid anisotropy, we can reduce the number of grid points required per wavelength to 4 for a l% tpper limit of error. This reduction of the number of grid points, achieved by using the weighted-averaging finite-element method, makes it possible to reduce computer memory to 32.7Vo of that for the eclectic finite-element method. We confirm the accuracy of our weighted-averaging finite-element method through accuracy analyses for a homogeneous and a horizontal-layer model. By synthetic data example, we reconfirm that our method is more efficient for simulating a geological model than previousf inite-element methodsThis work was financially supported by grant No. R05-2000-00003 from the Basic Research Program of the Korea Science & Engineering Foundation, grant No. PM10300 from Korea Ocean Research & Development Institute, National Laboratory Project of Ministry of Science and Technology, and Brain Korea 21 project of the Ministry of Education

A Survey on Ubiquitous Healthcare Service Demand among Diabetic Patients

BackgroundAdvanced information technology can be used when developing diagnostic and treatment strategies to provide better care for diabetic patients. However, the levels of need and demand for the use of technological advances have not been investigated in diabetic patients. We proposed and developed an individualized, ubiquitous (U)-healthcare service using advanced information technology for more effective glucose control. Prior to our service initiation, we surveyed patient needs and other pertinent information.MethodsDuring August 2009, we conducted a 34-item questionnaire survey among patients with diabetes who were older than 40 years in two certain hospitals in Korea.ResultsThe mean age of the 228 participants was 61.2±9 years, and males made up 49.1% of the sample. Seventy-one percent replied that they wanted individualized healthcare service, and they also wanted their health information to be delivered through mobile devices such as a cellular phone or a personal digital assistant (40.4%). Most patients had never heard of U-healthcare services (81.1%); however, after explaining the concept, 71.1% of participants responded that they would use the service if it was provided. Despite their willingness, participants were concerned about technical difficulty in using the service (26.3%) as well as the cost of the service (29.8%).ConclusionThe current study suggests that more than 70% of diabetic patients are interested in using U-healthcare services. To encourage widespread use, the application program or device of U-healthcare services should be simple, easy to use and affordable while also including a policy for the protection of private information

Idiopathic severe hypermagnesemia in an extremely low birth weight infant on the first day of life

A preterm female infant born at 27 weeks of gestation with a birth weight of 990 g developed acute hypotonia, apnea, hypotension and bradycardia mimicking septic shock syndrome at 14h after birth. Laboratory tests indicated a severe hypermagnesemia of 45 mg/dL. The renal function, complete blood count and maternal blood concentrations of magnesium were normal, and the blood cultures were negative. The patient recovered with treatment including exchange transfusion. However, the etiology of the severe hypermagnesemia remains unknown

Taurine chloramine differentially inhibits matrix metalloproteinase 1 and 13 synthesis in interleukin-1β stimulated fibroblast-like synoviocytes

It has been suggested that taurine chloramine (TauCl) plays an important role in the downregulation of proinflammatory mediators. However, little is known about its effect on the expression of matrix metalloproteinases (MMPs). In this study, we investigated the effects of TauCl on synovial expression of MMPs. The effects of TauCl on MMP expression in IL-1β stimulated fibroblast-like synoviocytes (FLSs) were studied using the following techniques. Real-time PCR and semi-quantitative PCR were employed to analyze the mRNA expression of MMPs. ELISA was used to determine protein levels of MMPs. Western blot analyses were performed to analyze the mitogen-activated protein kinase and inhibitor of nuclear factor-κB (IκB) kinase signalling pathways. Finally, electrophoretic mobility shift assay and immunohistochemistry were used to assess localization of transcription factors. IL-1β increased the transcriptional and translational levels of MMP-1 and MMP-13 in rheumatoid arthritis FLSs, whereas the levels of MMP-2 and MMP-9 were unaffected. TauCl at a concentration of 400 to 600 μmol/l greatly inhibited the transcriptional and translational expression of MMP-13, but the expression of MMP-1 was significantly inhibited at 800 μmol/l. At a concentration of 600 μmol/l, TauCl did not significantly inhibit phosphorylation of mitogen-activated protein kinase or IκB degradation in IL-1β stimulated rheumatoid arthritis FLSs. The degradation of IκB was significantly inhibited at a TauCl concentration of 800 μmol/l. The inhibitory effect of TauCl on IκB degradation was confirmed by electrophoretic mobility shift assay and immunochemical staining for localization of nuclear factor-κB. TauCl differentially inhibits the expression of MMP-1 and MMP-13, and inhibits expression of MMP-1 primarily through the inhibition of IκB degradation, whereas it inhibits expression of MMP-13 through signalling pathways other than the IκB pathway

Electroacupuncture Delays Hypertension Development through Enhancing NO/NOS Activity in Spontaneously Hypertensive Rats

Using spontaneously hypertensive rats (SHR), this study investigated whether electroacupuncture (EA) could reduce early stage hypertension by examining nitric oxide (NO) levels in plasma and nitric oxide synthase (NOS) levels in the mesenteric resistance artery. EA was applied to the acupuncture point Governor Vessel 20 (GV20) or to a non-acupuncture point in the tail twice weekly for 3 weeks under anesthesia. In conscious SHR and normotensive Wistar Kyoto (WKY) rats, blood pressure was determined the day after EA treatment by the tail-cuff method. We measured plasma NO concentration, and evaluated endothelial NO syntheses (eNOS) and neuronal NOS (nNOS) protein expression in the mesenteric artery. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lower after 3 weeks of GV20 treatment than EA at non-acupuncture point and no treatment control in SHR. nNOS expression by EA was significantly different between both WKY and no treatment SHR control, and EA at GV20 in SHR. eNOS expression was significantly high in EA at GV 20 compared with no treatment control. In conclusion, EA could attenuate the blood pressure elevation of SHR, along with enhancing NO/NOS activity in the mesenteric artery in SHR