81 research outputs found
Antheraea pernyi Silk Fiber: A Potential Resource for Artificially Biospinning Spider Dragline Silk
The outstanding properties of spider dragline silk are likely to be determined by a combination of the primary sequences and the secondary structure of the silk proteins. Antheraea pernyi silk has more similar sequences to spider dragline silk than the silk from its domestic counterpart, Bombyx mori. This makes it much potential as a resource for biospinning spider dragline silk. This paper further verified its possibility as the resource from the mechanical properties and the structures of the A. pernyi silks prepared by forcible reeling. It is surprising that the stress-strain curves of the A. pernyi fibers show similar sigmoidal shape to those of spider dragline silk. Under a controlled reeling speed of 95 mm/s, the breaking energy was 1.04 × 105 J/kg, the tensile strength was 639 MPa and the initial modulus was 9.9 GPa. It should be noted that this breaking energy of the A. pernyi silk approaches that of spider dragline silk. The tensile properties, the optical orientation and the β-sheet structure contents of the silk fibers are remarkably increased by raising the spinning speeds up to 95 mm/s
Verteporfin mitigates sepsis-induced liver injury by blocking macrophage-derived inflammation
Purpose: To study the role of yes-associated protein (YAP) inhibition by verteporfin (VTF) in LPSinduced acute liver injury (ALI) after sepsis.Methods: In vitro, VTF was used to treat LPS-stimulated RAW 267.4 cells. In vivo, LPS was injected to induce sepsis in mice, followed by treatment with VTF. The inflammatory mediators were determined using quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence spectroscopy (IF) and immunohistochemical staining (IHC), and the levels of YAP, P53 and ERK were measured by qRT-PCR, WB and IHC. Moreover, liver histology and liver function were examined using HE staining and ELISA respectively.Results: The results showed that VTF reduced YAP expression and inhibited LPS-induced cell activation and inflammatory cytokine production such as IL-6 and IL-1β, by attenuating the expressions of p53 and ERK pathway in macrophages. The levels of AST, AIL and TBiL remarkably decreased in ALI mice after VTF treatment (p < 0.05). Moreover, it was observed that inflammatory mediators, including inducible nitric oxide synthase (iNOS), IL-6 and IL-1β, decreased significantly in VTF treated mice (P < 0.05).Conclusion: VTF plays an antagonistic role in LPS-induced inflammatory response after ALI. Therefore, VTF is a potential medicinal agent for preventing infectious acute liver injury
Self-Assembly, Interfacial Nanostructure, and Supramolecular Chirality of the Langmuir-Blodgett Films of Some Schiff Base Derivatives without Alkyl Chain
A special naphthyl-containing Schiff base derivative, , -bis(2-hydroxy-1-naphthylidene)-1,2-phenylenediamine, was synthesized, and its coordination with various metal ions in situ at the air/water interface has been investigated. Although the ligand contains no alkyl chain, it can be spread on water surface. When metal ions existed in the subphase, an interfacial coordination between the ligand and different metal ions occurred in the spreading film, while different Nanostructures were fabricated in the monolayers. Interestingly to note that among various metal ions, only the in situ coordination-induced Cu(II)-complex film showed supramolecular chirality, although the multilayer films from the ligand or preformed complex are achiral. The chirality of the in situ Cu(II)-coordinated Langmuir film was developed due to the special distorted coordination reaction and the spatial limitation at the air/water interface. A possible organization mechanism at the air/water interface was suggested
Multivisceral resection of nonfunctional pancreatic neuroendocrine neoplasm with nearby organ invasion: a case report
Pancreatic neuroendocrine neoplasms (pNENs) are relatively rare epithelial malignancies originating from pancreatic neuroendocrine cells, pathologically classified into well-differentiated pancreatic neuroendocrine tumors (pNETs) and poorly-differentiated pancreatic neuroendocrine carcinoma (pNECs). Although they also fall under the category of pNENs, the almost entirely distinct biological characteristics and survival prognosis have caused debate among surgeons when it comes to the development of surgical intervention options, particularly for locally advanced G3 pNETs and pNECs. We present a case of 66-year-old male with nonfunctional G3 pNET, invasion of five nearby pancreatic organs and type II liver metastases. The patient achieved good outcomes after undergoing multivisceral resection and postoperative adjuvant chemotherapy. This finding helps surgeons better understand locally advanced pNENs, formulate treatment decisions systematically and confidently, and balance patient benefits and risks of surgery
A CsI hodoscope on CSHINE for Bremsstrahlung {\gamma}-rays in Heavy Ion Reactions
Bremsstrahlung production in heavy ion reactions at Fermi energies
carries important physical information including the nuclear symmetry energy at
supra-saturation densities. In order to detect the high energy Bremsstrahlung
rays, a hodoscope consisting of 15 CsI(Tl) crystal read out by photo
multiplier tubes has been built, tested and operated in experiment. The
resolution, efficiency and linear response of the units to rays have
been studied using radioactive source and reactions. The
inherent energy resolution of is obtained.
Reconstruction method has been established through Geant 4 simulations,
reproducing the experimental results where comparison can be made. Using the
reconstruction method developed, the whole efficiency of the hodoscope is about
against the emissions at the target position,
exhibiting insignificant dependence on the energy of incident rays
above 20 MeV. The hodoscope is operated in the experiment of Kr +
Sn at 25 MeV/u, and a full energy spectrum up to 80 MeV has
been obtained.Comment: 9 pages, 19 figure
Probing high-momentum component in nucleon momentum distribution by neutron-proton bremsstrahlung {\gamma}-rays in heavy ion reactions
The high momentum tail (HMT) of nucleons, as a signature of the short-range
correlations in nuclei, has been investigated by the high-energy bremsstrahlung
rays produced in Kr + Sn at 25 MeV/u. The energetic
photons are measured by a CsI(Tl) hodoscope mounted on the spectrometer CSHINE.
The energy spectrum above 30 MeV can be reproduced by the IBUU model
calculations incorporating the photon production channel from process in
which the HMTs of nucleons is considered. A non-zero HMT ratio of about
is favored by the data. The effect of the capture channel is
demonstrated
Modeling of Rate-Dependent Hysteresis Using a GPO-Based Adaptive Filter
A novel generalized play operator-based (GPO-based) nonlinear adaptive filter is proposed to model rate-dependent hysteresis nonlinearity for smart actuators. In the proposed filter, the input signal vector consists of the output of a tapped delay line. GPOs with various thresholds are used to construct a nonlinear network and connected with the input signals. The output signal of the filter is composed of a linear combination of signals from the output of GPOs. The least-mean-square (LMS) algorithm is used to adjust the weights of the nonlinear filter. The modeling results of four adaptive filter methods are compared: GPO-based adaptive filter, Volterra filter, backlash filter and linear adaptive filter. Moreover, a phenomenological operator-based model, the rate-dependent generalized Prandtl-Ishlinskii (RDGPI) model, is compared to the proposed adaptive filter. The various rate-dependent modeling methods are applied to model the rate-dependent hysteresis of a giant magnetostrictive actuator (GMA). It is shown from the modeling results that the GPO-based adaptive filter can describe the rate-dependent hysteresis nonlinear of the GMA more accurately and effectively
Effects of High Temperatures on the Physical and Mechanical Properties of Carbonated Ordinary Concrete
Fires are always known for seriously deteriorating concrete in structures, especially for those with certain carbonation due to long-time service. In this paper, 75 prism specimens were prepared and divided into four groups (three carbonated groups and one uncarbonated group). Specimens were tested under different temperatures (20, 300, 400, 500, 600, and 700°C), exposure times (3, 4, and 6 hours), and cooling methods (water and natural cooling). Surface characteristics, weight loss rate, and residual mechanical properties (strength, initial elastic modulus, peak, and ultimate compressive strains) of carbonated concrete specimens after elevated temperatures were investigated and compared with that of the uncarbonated ones. Results show that the weight loss rates of the carbonated concrete specimens are slightly lower than that of the uncarbonated ones and that the cracks are increased with raising of temperatures. Surface colors of carbonated concrete are significantly changed, but they are not sensitive to cooling methods. Surface cracks can be evidently observed on carbonated specimens when temperature reaches 400°C. Residual compressive strength and initial elastic modulus of carbonated concrete after natural cooling are generally larger than those cooled by water. The peak and ultimate compressive strains of both carbonated and uncarbonated concrete specimens increase after heating, but the values of the latter are greater than that of the former. Finally, the constitutive equation to predict the compressive behaviors of carbonated concrete after high temperatures was established and validated by tests
Role of humidity on the structures and properties of regenerated silk fibers
Silk fiber was processed from highly concentrated spinning dope to solid fibers along with water removal. To understand the mechanism of water removal during silk fiber spinning process, a microfluidic chip was designed and applied to investigate the structures and mechanical properties of two kinds of regenerated silk fibroin fibers dry-spun at different relative humidity. The experimental results showed that the diameters of the fibers spun at 40% RH are always larger than the fibers spun at 50% RH due to different removal rates of water. The fibers spun at low humidity contain more β-sheet structure and lower degree of chain orientation and crystalline orientation. These results indicate that the fast phase transition of silk fibroin from sol–gel to silk fiber undergoes with rapid water removal and higher fiber orientation relates to more residue water and drawing force
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