59 research outputs found
Automatic Internal Stray Light Calibration of AMCW Coaxial Scanning LiDAR Using GMM and PSO
In this paper, an automatic calibration algorithm is proposed to reduce the
depth error caused by internal stray light in amplitude-modulated continuous
wave (AMCW) coaxial scanning light detection and ranging (LiDAR). Assuming that
the internal stray light generated in the process of emitting laser is static,
the amplitude and phase delay of internal stray light are estimated using the
Gaussian mixture model (GMM) and particle swarm optimization (PSO).
Specifically, the pixel positions in a raw signal amplitude map of calibration
checkboard are segmented by GMM with two clusters considering the dark and
bright image pattern. The loss function is then defined as L1-norm of
difference between mean depths of two amplitude-segmented clusters. To avoid
overfitting at a specific distance in PSO process, the calibration check board
is actually measured at multiple distances and the average of corresponding L1
loss functions is chosen as the actual loss. Such loss is minimized by PSO to
find the two optimal target parameters: the amplitude and phase delay of
internal stray light. According to the validation of the proposed algorithm,
the original loss is reduced from tens of centimeters to 3.2 mm when the
measured distances of the calibration checkboard are between 1 m and 4 m. This
accurate calibration performance is also maintained in geometrically complex
measured scene. The proposed internal stray light calibration algorithm in this
paper can be used for any type of AMCW coaxial scanning LiDAR regardless of its
optical characteristics
Highly precise AMCW time-of-flight scanning sensor based on digital-parallel demodulation
In this paper, a novel amplitude-modulated continuous wave (AMCW)
time-of-flight (ToF) scanning sensor based on digital-parallel demodulation is
proposed and demonstrated in the aspect of distance measurement precision.
Since digital-parallel demodulation utilizes a high-amplitude demodulation
signal with zero-offset, the proposed sensor platform can maintain extremely
high demodulation contrast. Meanwhile, as all cross correlated samples are
calculated in parallel and in extremely short integration time, the proposed
sensor platform can utilize a 2D laser scanning structure with a single photo
detector, maintaining a moderate frame rate. This optical structure can
increase the received optical SNR and remove the crosstalk of image pixel
array. Based on these measurement properties, the proposed AMCW ToF scanning
sensor shows highly precise 3D depth measurement performance. In this study,
this precise measurement performance is explained in detail. Additionally, the
actual measurement performance of the proposed sensor platform is
experimentally validated under various conditions
Expression of Phospholipase A2 Receptor in Pediatric Hepatitis B Virus-Related Membranous Nephropathy
Purpose Hepatitis B virus (HBV) infection is among etiologies of secondary membranous nephropathy (MN) in pediatric patients. We evaluated expression of phospholipase A2 receptor (PLA2R), a specific target antigen of primary MN, in pediatric HBV-related MN. Methods We retrospectively reviewed patients with biopsy-proven HBV-related MN from the renal biopsy registry and electronic medical records of Severance Hospital, Seoul, Korea, from 1993 to 2004. Paraffin-embedded human kidney tissues were retrieved and immunohistochemically stained for PLA2R. Results Ten pediatric patients with 13 biopsied specimens were reviewed. The predominant pathological stage was stage II–III, and second was stage II. The intensity of staining for IgG was greatest, with less intense staining for IgM, IgA, C3, C4, and C1q. All the patients had angiotensin-converting enzyme inhibitor combined with glucocorticoid, and four patients converted to cyclosporine treatment from glucocorticoid monotherapy. Urinalysis of all the patients normalized after variable period. PLA2R staining was demonstrated in the outer glomerulus in 3 out of 13 biopsies, 2 of which were obtained from the same patient over a 5-year interval. Conclusions PLA2R was expressed in a small number of cases diagnosed as pediatric HBV-related MN, indicating that some HBV-related MN cases may be primary MN concurrent with HBV infection
High-yield exfoliation of three-dimensional graphite into two-dimensional graphene-like sheets
Edge-functionalized graphite (EFG) is prepared via a "direct'' covalent attachment of organic molecular wedges. The EFG is dispersed in N-methyl-2-pyrrolidone with a concentration as high as 0.27 mg mL(-1), leading to high-yield exfoliation of the three-dimensional graphite into two-dimensional graphene-like sheets.close464
Transition metal-doped Ni-rich layered cathode materials for durable Li-ion batteries
Doping is a well-known strategy to enhance the electrochemical energy storage performance of layered cathode materials. Many studies on various dopants have been reported; however, a general relationship between the dopants and their effect on the stability of the positive electrode upon prolonged cell cycling has yet to be established. Here, we explore the impact of the oxidation states of various dopants (i.e., Mg2+, Al3+, Ti4+, Ta5+, and Mo6+) on the electrochemical, morphological, and structural properties of a Ni-rich cathode material (i.e., Li[Ni0.91Co0.09]O2). Galvanostatic cycling measurements in pouch-type Li-ion full cells show that cathodes featuring dopants with high oxidation states significantly outperform their undoped counterparts and the dopants with low oxidation states. In particular, Li-ion pouch cells with Ta5+- and Mo6+-doped Li[Ni0.91Co0.09]O2 cathodes retain about 81.5% of their initial specific capacity after 3000 cycles at 200???mA???g???1. Furthermore, physicochemical measurements and analyses suggest substantial differences in the grain geometries and crystal lattice structures of the various cathode materials, which contribute to their widely different battery performances and correlate with the oxidation states of their dopants
Sasa borealis leaves extract improves insulin resistance by modulating inflammatory cytokine secretion in high fat diet-induced obese C57/BL6J mice
Obesity is considered a mild inflammatory state, and the secretion of inflammation-related cytokines rises as adipose tissue expands. Inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interlukin 6 (IL-6) and monocyte-chemoattractant protein 1 (MCP-1), are modulated by adipose tissue and known to play an important role in insulin resistance which is the common characteristics of obesity related disorders. In this study we analyzed the effects of Sasa borealis leaves extract on inflammatory cytokines and insulin resistance in diet induced obese C57/BL6J mice. The obese state was induced by a high fat diet for 20 weeks and then the mice were divided into two groups; obese control group (OBC, n = 7) and experimental group (OB-SBE, n = 7). The OBC group was fed a high fat diet and the OB-SBE group was fed a high fat diet containing 5% Sasa borealis leaves extract (SBE) for 12 weeks. We also used mice fed a standard diet as a normal control (NC, n = 7). The body weight and adipose tissue weight in the OB group were significantly higher than those in the NC group. The effects of the high fat diet were reduced by SBE treatments, and the body weight and adipose tissue deposition in the OB-SBE group were significantly decreased compared to the OBC group. The OBC group showed higher serum glucose and insulin levels which resulted in a significant increase of incremental area under the curve (IAUC) and HOMA-IR than the NC group. Also, serum leptin, TNF-α, and IL-6 levels were significantly higher in the OBC group than in the NC group. In contrast, the OB-SBE group showed a reversal in the metabolic defects, including a decrease in glucose, insulin, IAUC, HOMA-IR, TNF-α, IL-6 and leptin levels. These results suggest that BSE can suppress increased weight gain and/or fat deposition induced by a high fat diet and theses effects are accompanied by modulation of the inflammatory cytokines, TNF-α and IL-6 secretion resulting in improved insulin resistance
Clinical outcomes and prognostic factors in patients with breast diffuse large B cell lymphoma; Consortium for Improving Survival of Lymphoma (CISL) study
<p>Abstract</p> <p>Background</p> <p>The breast is a rare extranodal site of non-Hodgkin lymphoma, and primary breast lymphoma (PBL) has been arbitrarily defined as disease localized to one or both breasts with or without regional lymph nodes involvement. The aim of this study was to evaluate the clinical outcomes in patients with diffuse large B cell lymphoma (DLBCL) and breast involvement, and to find the criteria of PBL reflecting the outcome and prognosis.</p> <p>Methods</p> <p>We retrospectively analyzed data from 68 patients, newly diagnosed with DLBCL and breast involvement at 16 Korean institutions between January 1994 and June 2009.</p> <p>Results</p> <p>Median age at diagnosis was 48 years (range, 20-83 years). Forty-three (63.2%) patients were PBL according to previous arbitrary criteria, sixteen (23.5%) patients were high-intermediate to high risk of international prognostic index. The patients with one extranodal disease in the breast (OED) with or without nodal disease were 49 (72.1%), and those with multiple extranodal disease (MED) were 19 (27.9%). During median follow-up of 41.5 months (range, 2.4-186.0 months), estimated 5-year progression-free survival (PFS) was 53.7 ± 7.6%, and overall survival (OS) was 60.3 ± 7.2%. The 5-year PFS and OS was significantly higher for patients with the OED group than those with the MED group (5-year PFS, 64.9 ± 8.9% vs. 27.5 ± 11.4%, p = 0.001; 5-year OS, 74.3 ± 7.6% vs. 24.5 ± 13.0%, p < 0.001). In multivariate analysis, MED (hazard ratio [HR], 3.61; 95% confidence interval [CI], 1.07-12.2) and fewer than four cycles of systemic chemotherapy with or without local treatments (HR, 4.47; 95% CI, 1.54-12.96) were independent prognostic factors for worse OS. Twenty-five (36.8%) patients experienced progression, and the cumulative incidence of progression in multiple extranodal sites or other than breasts and central nervous system was significantly different between the OED group and the MED group (5-year cumulative incidence, 9.7 ± 5.4% vs. 49.0 ± 15.1%, p = 0.001).</p> <p>Conclusions</p> <p>Our results show that the patients included in OED group, reflecting different treatment outcome, prognosis and pattern of progression, should be considered as PBL in the future trial. Further studies are warranted to validate our suggested criteria.</p
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Freeze-Dried Sulfur–Graphene Oxide–Carbon Nanotube Nanocomposite for High Sulfur-Loading Lithium/Sulfur Cells
The
ambient-temperature rechargeable lithium/sulfur (Li/S) cell
is a strong candidate for the beyond lithium ion cell since significant
progress on developing advanced sulfur electrodes with high sulfur
loading has been made. Here we report on a new sulfur electrode active
material consisting of a cetyltrimethylammonium bromide-modified sulfur–graphene
oxide–carbon nanotube (S-GO-CTA-CNT) nanocomposite prepared
by freeze-drying. We show the real-time formation of nanocrystalline
lithium sulfide (Li<sub>2</sub>S) at the interface between the S-GO-CTA-CNT
nanocomposite and the liquid electrolyte by in situ TEM observation
of the reaction. The combination of GO and CNT helps to maintain the
structural integrity of the S-GO-CTA-CNT nanocomposite during lithiation/delithiation.
A high S loading (11.1 mgS/cm<sup>2</sup>, 75% S) S-GO-CTA-CNT electrode
was successfully prepared using a three-dimensional structured Al
foam as a substrate and showed good S utilization (1128 mAh/g S corresponding
to 12.5 mAh/cm<sup>2</sup>), even with a very low electrolyte to sulfur
weight ratio of 4. Moreover, it was demonstrated that the ionic liquid
in the electrolyte improves the Coulombic efficiency and stabilizes
the morphology of the Li metal anode
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