33 research outputs found
On the Validation of a Multiple-Network Poroelastic Model Using Arterial Spin Labeling MRI Data
The Multiple-Network Poroelastic Theory (MPET) is a numerical model to characterize the transport of multiple fluid networks in the brain, which overcomes the problem of conducting separate analyses on individual fluid compartments and losing the interactions between tissue and fluids, in addition to the interaction between the different fluids themselves. In this paper, the blood perfusion results from MPET modeling are partially validated using cerebral blood flow (CBF) data obtained from arterial spin labeling (ASL) magnetic resonance imaging (MRI), which uses arterial blood water as an endogenous tracer to measure CBF. Two subjectsâone healthy control and one patient with unilateral middle cerebral artery (MCA) stenosis are included in the validation test. The comparison shows several similarities between CBF data from ASL and blood perfusion results from MPET modeling, such as higher blood perfusion in the gray matter than in the white matter, higher perfusion in the periventricular region for both the healthy control and the patient, and asymmetric distribution of blood perfusion for the patient. Although the partial validation is mainly conducted in a qualitative way, it is one important step toward the full validation of the MPET model, which has the potential to be used as a testing bed for hypotheses and new theories in neuroscience research
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Effects of single-leg foot-landing techniques on ground reaction force and electromyography
Anterior Cruciate Ligament (ACL) injury has deleterious consequences on athletes both psychologically and financially. As the worldwide prevalence of ACL injury remains high today, developing prevention strategies is essential. The study aimed to examine the effects of foot-landing techniques on vertical ground reaction force (vGRF) and electromyographic (EMG) activities of the lower extremity during single-leg drop-landings. It was hypothesized that forefoot landing would result in lower vGRF and higher muscular activities of medial gastrocnemius (MG) and soleus as compared with flat-foot landing. Fifteen male basketball athletes (age = 23.6 ± 1.9 years, height = 175.4 ± 8.0 cm, mass = 68.4 ± 10.0 kg) with no previous surgery and existing injury on the lower extremity were each tasked to perform single-leg drop-landings from a 30 cm platform onto a force plate using three different foot techniques (self-preferred, forefoot, flat-foot). Kinematics, vGRF and EMG data were recorded. Values of EMG were separated into two sets of averaged data (landing phase, pre-landing phase). Flat-foot landing produced a significantly higher peak vGRF compared to self-preferred and flat-foot landings (p < .001). There were significant main effects in MG between different foot-landing techniques (p = .002) and between different phases of landing (p = .037). Significant interactions were observed between foot-landing technique and phase of landing in MG (p = .035), as well as in soleus (p = .031). These results demonstrate that forefoot landing technique can effectively activate calf muscles and lower vGRF, hence mitigating the possible risk of non-contact ACL injury.Bachelor of Science (Sport Science and Management
Novel composite in situ obtained from coal gasification coarse slag and its mechanism of removing phosphate
A novel low-cost hematiteâsilicon mesoporous composite (HSMC) was synthesized in situ from coal gasification coarse slag (CGCS) via acid modification and its potential for phosphate removal from wastewater was studied. Calcium, aluminum and iron in CGCS were activated by hydrochloric acid, and formed crystalline hematite on the quartz and silicates substrates. Compared with traditional methods of preparing hematite, this in-situ preparation method effectively utilized the iron in CGCS instead of requiring added iron salts, which is highly cost-effective. The specific surface area increased from 4Â m2/g for CGCS to 67Â m2/g for HSMC, greatly enhancing the phosphate removal ability of HSMC. The maximum adsorption capacity of HSMC for phosphate was 28.62Â mg/g, which is more than 28 times higher than that of CGCS. The HSMC had a high point of zero charge (pHPZC) of 7.5, providing good phosphate removal performance over a wide pH range. The phosphate removal mechanism of HSMC mainly involves ligand exchange induced by the large number of hydroxyl groups, inner-sphere complexation induced by the presence of major metal (hydr)oxides, the precipitation of calcium and aluminum with phosphate groups, and some electrostatic adsorption induced by the positively charged surface. The contribution of precipitation to the phosphate removal ability was approximately 27Â %. This study provides a new method for the development of phosphate adsorbents while recycling CGCS
Effect of tungsten based coating characteristics on microstructure and thermal conductivity of diamond/Cu composites prepared by pressueless infiltration
Tungsten coatings were deposited on diamond particles by vacuum magnetron sputtering. The coated diamond particles were firstly heat treated at different temperatures, and diamond/copper (Cu) composites were fabricated by using a pressureless infiltration method afterwards. The influences of heat treatment on the microstructure and composition of tungsten based coating surface and diamond/copper composites were analysed. Notable differences were found in the microstructure with heating temperatures. Moreover, the tungsten based coating surface contained large quantities of oxidised tungsten, and the phase composition of the coatings varied within the range of tungstenâW 2 CâWC as the heat treatment temperature increased. The fracture surface morphologies in the copper matrix composites reinforced with diamond particles with coatings were identically characterised with the presence of ductile fracture of matrix accompanied by dissociation of diamond particles from the matrix. The thermal conductivity (TC) and gas tightness behaviours of the diamond/copper composites were also explored. A maximum TC of 768 W m â1 K â1 and a fine gas tightness of 2.5 Ă 10-10 Pa m 3 /s were obtained with reinforcement of tungsten-coated diamond particles treated at 800 °C. The value of the interface thermal resistance between copper and diamond particles was also estimated and specifically discussed. Accepted Author ManuscriptImPhys/Optic
Full N,N-Methylation of 4,4âČ-Methylenedianiline with Dimethyl Carbonate: A Feasible Access to 4,4âČ-Methylene bis(N,N-Dimethylaniline)
The full N,N-methylation of 4,4âČ-methylenedianiline (MDA) with dimethyl carbonate (DMC) was investigated. The yield of the major product 4,4âČ-methylene bis(N,N-dimethylaniline) (MBDMA) reached as high as 97% over NaY catalyst at 190°C for 6âh. The catalyst could be used for two more times with acceptable MBDMA yields higher than 90%. The main by-products were identified as three N-methylated derivatives. Surprisingly, the formation of the N-methoxycarbonylation product was extremely restrained, which could be produced in high yields of 98% on zinc acetate catalyst. Furthermore, the reaction pathway to the major product MBDMA was proposed. Finally, a feasible synthetic route of 4,4âČ-methylene bis(N,N-dimethylaniline) (MBDMA) was established, featuring a high yield, mild reaction conditions, and simple operations
Intracellular self-assembly of nanoparticles for enhancing cell uptake
National Natural Science Foundation of China [21175122, 91127036]; Fundamental Research Funds for Central Universities [WK2060190018]; Anhui Provincial Natural Science Foundation [1108085J17]A radioactive probe (1) has been developed and applied to a condensation reaction and self-assembly of radioactive nanoparticles (i.e., I-125-NPs) intracellularly. Upon 160 min cellular efflux, the radioactivity retained in cells incubated with 1 was 4-fold more higher than that of those cells treated with a scrambled control probe (1-Scr)
Sedimentary architecture and distribution of intra-platform shoal in sequence framework of Permian Changxing Formation in central Sichuan Basin, SW China
Based on the comprehensive analysis of core, thin section, logging and seismic data, this study carried out the identification and comparison of Permian Changxing Formation sequences, clarified the typical sedimentary architectures of intra-platform shoal, investigated the vertical and horizontal development and distribution of intra-platform shoal in each sequence, and thus established the sedimentary evolution model of shoal body. The study results are reflected in four aspects. First, there are two complete third-order sequences (SQ1 and SQ2) in Changxing Formation in central Sichuan Basin. SQ1 is generally thick in the north and thin in the south, and SQ2 shows a thickness differentiation trend of âtwo thicknesses and three thinnessesâ. Second, the Changxing Formation in central Sichuan Basin mainly develops intra-platform shoal, inter-shoal sea and intra-platform depression subfacies. In the vertical direction, the intra-platform shoal mainly presents two typical sedimentary sequences: stable superposed and high-frequency interbedded. Third, the stable superimposed sedimentary sequence is developed in the shoal belt at the edge of intra-platform depression, which is composed of two shoal-forming periods and located in the highstand systems tracts (HSTs) of SQ1 and SQ2. The high-frequency interbedded sedimentary sequence is developed in the southern shoal belt of intra-platform depression, which is composed of four shoal-forming periods and mainly located in the HST of SQ2. Fourth, during the SQ1 deposition, the intra-platform shoal was mainly developed at the edge of the intra-platform depression on the north side of the study area, and the inter-shoal sea subfacies was mainly developed on the south side. During the SQ2 deposition, the intra-platform shoal was widely developed in the area, forming two nearly parallel intra-platform shoal belts. The study results provide direction and ideas for exploration of Changxing Formation intra-platform shoal reservoirs in central Sichuan Basin
Identification of <i>Fusarium oxysporum</i> Causing Leaf Blight on <i>Dendrobium chrysotoxum</i> in Yunnan Province, China
Leaf-blight disease caused by the Fusarium oxysporum is an emerging problem in Dendrobium chrysotoxum production in China. Symptoms of leaf blight were observed on seedlings of D. chrysotoxum cultivated in a nursery in Ruili City, Yunnan Province, China. In this study, we isolated the Fusarium sp. associated with leaf-blight disease of D. chrysotoxum from the diseased seedlings. A pathogenicity test was performed to fulfill Kochâs postulates to confirm the pathogenicity of isolated strains and identified using morphological and molecular techniques. The results revealed that all four isolated Fusarium sp. isolates (DHRL-01~04) produced typical blight symptoms followed by marginal necrosis of leaves on the D. chrysotoxum plants. On the PDA medium, the fungal colony appeared as a white to purplish color with cottony mycelium growth. Microconidia are oval-shaped, whereas macroconidia are sickle-shaped, tapering at both ends with 2â4 septations. The phylogenetic trees were construed based on internal transcribed spacer (ITS), translation elongation factor (EF-1α), and RNA polymerase subunit genes RPB1 and RPB2 genes, respectively, and blasted against the NCBI database for species confirmation. Based on the NCBI databaseâs blast results, the isolates showed that more than 99% identify with Fusarium oxysporum. To our knowledge, this is the first comprehensive report on the identification of Fusarium oxysporum as the causal agent of Dendrobium chrysotoxum leaf blight in Yunnan Province, China, based on morphological and molecular characteristics