291 research outputs found
Measurement of and Factors Associated with the Anterior Chamber Volume in Healthy Chinese Adults
Purpose. To measure the anterior chamber volume (ACV) and determine factors associated with the ACV in healthy Chinese adults. Methods. In this cross-sectional study, we used swept-source optical coherence tomography (SS-OCT) to measure ACV and other anterior segment parameters. Factors associated with ACV were also determined. Results. A total of 313 healthy Chinese adults were enrolled. The anterior segment parameters, including ACV, could be measured by SS-OCT with excellent repeatability and reproducibility. There was a significant difference between the horizontal and vertical anterior chamber widths (ACW) (P<0.05), with a mean difference of 390 μm. The ACV (mean 153.83±32.42 mm3) was correlated with most of the anterior segment parameters, especially anterior chamber depth (ACD), which accounted for about 85% of the variation of ACV. Most of the anterior segment parameters were significantly correlated with age, and the relative changes in ACV and ACD were greatest in subjects aged 41–50 years. Conclusion. ACV was correlated with most of the anterior segment parameters measured in this study, particularly ACD. The relatively large difference between horizontal and vertical ACW suggests that the ACV could and should be measured using multiple OCT scans
Analysis of Multiple Interfacial Cracks in Three Dimensional Bimaterials Using Hypersingular Integral-Differential Equation Method
By using the concept of finite-part integral, a set of hypersingular integro-differential equations for multiple interfacial cracks in a three-dimensional infinite bimaterial subjected to arbitrary loads is derived. In the numerical analysis, unknown displacement discontinuities are approximated with the products of the fundamental density functions and power series. The fundamental functions are chosen to express a two-dimensional interface crack rigorously. As illustrative examples, the stress intensity factors for two rectangular interface cracks are calculated for various spacing, crack shape and elastic constants. It is shown that the stress intensity factors decrease with the crack spacing
FAK Promotes Osteoblast Progenitor Cell Proliferation and Differentiation by Enhancing Wnt Signaling
Decreased bone formation is often associated with increased bone marrow adiposity. The molecular mechanisms that are accountable for the negative correlation between bone mass and bone marrow adiposity are incompletely understood. Focal adhesion kinase (FAK) has critical functions in proliferation and differentiation of many cell types; however, its roles in osteoblast lineage cells are largely unknown. We show herein that mice lacking FAK in Osterixâ expressing cells exhibited decreased osteoblast number and low bone mass as well as increased bone marrow adiposity. The decreased bone mass in FAKâ deficient mice was accounted for by decreased proliferation, compromised osteogenic differentiation, and increased adipogenic differentiation of bone marrow Osterixâ expressing cells resulting from downregulation of Wnt/βâ catenin signaling due to the reduced expression of canonical Wnt ligands. In contrast, FAK loss in calvarial preosteoblasts had no adverse effect on their proliferation and osteogenic differentiation and these cells had intact Wnt/βâ catenin signaling. © 2016 American Society for Bone and Mineral Research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135488/1/jbmr2908_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135488/2/jbmr2908-sup-0001-SuppData-S1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/135488/3/jbmr2908.pd
Experimental study on the shear stiffness and damping ratio of the coarse-grained soil against geogrid interface
Geosynthetic-reinforced soil structures are mostly used to retain subgrade slope of highway and railway. For the design and performance analyses of geosynthetic-reinforced soil structures under repeated loading, such as those induced by compaction, traffic and earthquakes, the understanding of cyclic soil–geosynthetic interface behaviour is of great interest. Nevertheless, experimental data concerning this type of behaviour are very scarce. A laboratory study was carried out and is described in this paper. This paper presents the behaviour of an interface between a coarse-grained soil and a geogrid under cyclic loading conditions. A large-scale direct shear test device able to perform displacement-controlled cyclic tests was used. The results obtained are presented and discussed, especially the effects of the displacement amplitude and normal stress on the shear stiffness and damping ratio are investigated. The dynamic response parameters of the soil-geosynthetic interface are greatly affected by the number of cycles, and the variations in the two parameters with the number of cycles are related to the normal stress and the shear displacement amplitude. when at large displacements, the damping ratio decreases first and then stabilizes with the number of cycles. However, at small displacement, the shear stiffness and damping ratio are all decrease somewhat at the initial stage of cyclic shearing. As the experimental materials used in this study are relatively single, and further experimental research should be carried out in the future. The shear parameters of interface in this study can provide reference for the design of reinforced soil structure
Case Report: Primary hepatic neuroendocrine tumor: two cases report with literature review
Background & AimsPrimary hepatic neuroendocrine tumors (PHNETs) are rare malignant liver tumors that present diagnostic challenges owing to their rarity and absence of specific clinical features. This study aimed to investigate the characteristics of this rare liver tumor to enhance our understanding of the disease, improve diagnostic accuracy, and explore standardized diagnostic and treatment approaches.Case descriptionDuring physical examination, two elderly women, aged 64 and 74 years, were found to have liver masses. 18F-FDG Positron Emission Tomography-Computed Tomography (18F-FDG PET-CT) and Ga68-DOTATATE PET-CT scans of both individuals revealed multiple liver masses that were initially suspected to be hepatic neuroendocrine tumors. Subsequent puncture pathology confirmed the diagnosis of neuroendocrine tumors. Furthermore, in Case 1, the tumor was also detected by 18F-FDG PET-CT in the lung, suggesting a metastatic tumor, in conjunction with liver immunohistochemistry and imaging findings. Laboratory tests revealed no significant abnormalities in liver function or autoimmune liver disease indicators, and there was no evidence of viral hepatitis infection. However, partial hepatectomy was not indicated for cases with distant metastasis or multiple space-occupying lesions. Individualized treatment approaches have been developed for such situations. A large portion of the tumor underwent Transarterial Embolization (TAE), and targeted combination chemotherapy or endocrine therapy was administered based on the pathological results. During regular follow-ups a 13 and 12 months, the tumor remained stable. The patients’ quality of life was good, and their psychological well-being was healthy. They led active lifestyles, demonstrated a thorough understanding of their disease and its progression, and actively cooperated during the follow-up process.ConclusionOur findings suggest that a combination of serological, radiological, and immunohistochemical examinations can aid in the diagnosis of PHNET. In addition, we determined that TAE combined with drug therapy could be an effective method for controlling PHNET progression. Regular postoperative follow-ups are important for monitoring the prognosis and tumor progression status of patients with PHNET
Application of Metal Oxide Heterostructures in Arsenic Removal from Contaminated Water
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It has become one of the major environmental problems for people worldwide to be exposed to high arsenic concentrations through contaminated drinking water, and even the long-term intake of small doses of arsenic has a carcinogenic effect. As an efficient and economic approach for the purification of arsenic-containing water, the adsorbents in adsorption processes have been widely studied. Among a variety of adsorbents reported, the metal oxide heterostructures with high surface area and specific affinity for arsenic adsorption from aqueous systems have demonstrated a promising performance in practical applications. This review paper aims to summarize briefly the metal oxide heterostructures in arsenic removal from contaminated water, so as to provide efficient, economic, and robust solutions for water purification.</p
A High-Performance Mid-infrared Optical Switch Enabled by Bulk Dirac Fermions in Cd3As2
Pulsed lasers operating in the 2-5 {\mu}m band are important for a wide range
of applications in sensing, spectroscopy, imaging and communications. Despite
recent advances with mid-infrared gain media, the lack of a capable pulse
generation mechanism, i.e. a passive optical switch, remains a significant
technological challenge. Here we show that mid-infrared optical response of
Dirac states in crystalline Cd3As2, a three-dimensional topological Dirac
semimetal (TDS), constitutes an ideal ultrafast optical switching mechanism for
the 2-5 {\mu}m range. Significantly, fundamental aspects of the photocarrier
processes, such as relaxation time scales, are found to be flexibly controlled
through element doping, a feature crucial for the development of convenient
mid-infrared ultrafast sources. Although various exotic physical phenomena have
been uncovered in three-dimensional TDS systems, our findings show for the
first time that this emerging class of quantum materials can be harnessed to
fill a long known gap in the field of photonics.Comment: 17 pages, 3 figure
Serum level of S100A8/A9 as a biomarker for establishing the diagnosis and severity of community-acquired pneumonia in children
BackgroundS100A8/A9, which is a member of S100 proteins, may be involved in the pathophysiology of Community-acquired pneumonia (CAP) that seriously threatens children’s health. However, circulating markers to assess the severity of pneumonia in children are yet to be explored. Therefore, we aimed to investigate the diagnostic performance of serum S100A8/A9 level in determining the severity of CAP in children.MethodsIn this prospective and observational study, we recruited 195 in-hospital children diagnosed with CAP. In comparison, 63 healthy children (HC) and 58 children with non-infectious pneumonia (pneumonitis) were included as control groups. Demographic and clinical data were collected. Serum S100A8/A9 levels, serum pro-calcitonin concentrations, and blood leucocyte counts were quantified.ResultsThe serum S100A8/A9 levels in patients with CAP was 1.59 ± 1.32 ng/mL, which was approximately five and two times higher than those in healthy controls and those in children with pneumonitis, respectively. Serum S100A8/A9 was elevated parallelly with the clinical pulmonary infection score. The sensitivity, specificity, and Youden’s index of S100A8/A9 ≥1.25 ng/mL for predicting the severity of CAP in children was optimal. The area under the receiver operating characteristic curve of S100A8/A9 was the highest among the indices used to evaluate severity.ConclusionsS100A8/A9 may serve as a biomarker for predicting the severity of the condition in children with CAP and establishing treatment grading
Sensitive and Ultrabroadband Phototransistor Based on Two-Dimensional Bi2O2Se Nanosheets
Bi2O2Se, a high-mobility and air-stable 2D material, has attracted substantial attention for application in integrated logic electronics and optoelectronics. However, achieving an overall high performance over a wide spectral range for Bi2O2Se-based devices remains a challenge. A broadband phototransistor with high photoresponsivity (R) is reported that comprises high-quality large-area (≈180 µm) Bi2O2Se nanosheets synthesized via a modified chemical vapor deposition method with a face-down configuration. The device covers the ultraviolet (UV), visible (Vis), and near-infrared (NIR) wavelength ranges (360–1800 nm) at room temperature, exhibiting a maximum R of 108 696 A W−1 at 360 nm. Upon illumination at 405 nm, the external quantum efficiency, R, and detectivity (D*) of the device reach up to 1.5 × 107%, 50055 A W−1, and 8.2 × 1012 Jones, respectively, which is attributable to a combination of the photogating, photovoltaic, and photothermal effects. The devices reach a −3 dB bandwidth of 5.4 kHz, accounting for a fast rise time (τrise) of 32 µs. The high sensitivity, fast response time, and environmental stability achieved simultaneously in these 2D Bi2O2Se phototransistors are promising for high-quality UV and IR imaging applications
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