Isothermal oxidation of the plain and palladium modified aluminide coatings, developed by the low-pressure pack cementation process, on the nickel-base superalloy IN738, has been carried out at ...900∼1100 °C, with the primary objective of systematically understanding the coating degradation process during oxidation, by XRD, optical microscopy (OM) and energy dispersive X-ray spectrometry (EDS). Results show that the degradation mechanism of the (Ni,Pd)Al coating is similar to the plain NiAl coating. The microstructural degradation of both the (Ni,Pd)Al coating and NiAl coatings occurs due to phase transformation from
β to
γ′ during oxidation at high temperature. Palladium may play a significant role in stabilizing the
β phase, retarding the degradation of coating, and increasing the coating performance for high temperature oxidation resistance.
To investigate the efficacy and safety of a new endoscopic anastomosis clip in the treatment of defects after endoscopic full-thickness resection (EFTR).
Retrospective cohort study. Fourteen patients ...4 males and 10 females, aged (55.9±8.2) years (45-69 years) with gastric submucosal tumors underwent EFTR at the First Affiliated Hospital of Soochow University were included from December 2018 to January 2021. Patients were divided into new anastomotic clamp group (
=6) and nylon ring combined with metal clips group (
=8). Preoperative endoscopic ultrasound examinations were required to all patients to evaluate the wound condition. The size of the defect, operation time required for wound closure, success rate of closure, postoperative gastric tube placement time, postoperative hospital stay, incidence of complications, preoperative and postoperative serological indexes were compared between the two groups. All patients were followed up after the operation, among which the general endoscopy was reviewed in the
Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diverse cellular responses through signal transduction pathways including the protein kinase C (PKC) ...pathway. In the present study, we sought to determine the effect of PMA on mucin gene expression and on the biological properties of a human colon cancer cell line, HM3. The cells were treated for 8 and 24 h with various concentrations of PMA and total RNA was extracted and Northern and slot blot analyses were carried out using MUC2, MUC3 and MUC5AC mucin cDNA probes to assess the steady state levels of mRNA. Spent media were collected and the level of cancer associated carbohydrate antigens (T, Tn, sialyl Tn, sialyl Lex, and sialyl Lea) and matrix-degrading metalloproteinase (MMPs) activity were examined. Trypsinized cells were used for assessing in vitro invasion, motility and adhesion to matrigel. Our results showed that PMA caused upregulation of steady state mRNA levels of MUC2, MUC3 and MUC5AC which was inhibited after treatment with protein synthesis inhibitors. Calphostin C, a highly specific inhibitor of protein kinase C significantly inhibited the PMA induced induction of mRNA levels of MUC2, MUC3, and MUC5AC. The levels of all cancer-associated mucin carbohydrate antigens examined in the media were increased by PMA treatment. PMA also caused an increase in MMPs activity and in in vitro invasion and motility properties, but did not affect adhesion of HM3 cells to matrigel. Thus, PMA caused a significant increase in the expression of all three mucin genes through signaling pathways involving protein kinase C and increased secretion of mucin associated carbohydrate antigens. These changes were associated with increases in MMP activity as well as by increases in the invasive and motility properties of HM3 colon cancer cells. These data suggest that protein kinase C signaling pathways may be involved in mucin gene regulation and in modulating the invasive and metastatic properties of colon cancer cells.
Abstract
The supply of lubrication oil has a great influence on the reliability and efficiency of a scroll compressor, because oil plays a role in lubrication, sealing, and heat transfer in the ...compressor. In this work, a comprehensive steady and transient analysis on the oil supply system of a high-pressure shell scroll compressor was carried out using a commercial computational fluid dynamics (CFD) program. Various parameters, including pressure difference, compressor rotation speed, oil temperature, bearing clearance, and diameter of the oil gallery, were investigated to find the relations with oil flowrate. Among them, oil temperature and bearing clearance are indicated as the most sensitive, and pressure difference follows. Compressor rotation speed and diameter of the oil gallery are insensitive. Some hydrodynamic parameters can also be obtained in detail, such as pressure drop and oil flow velocity. This CFD analysis has proved to be helpful for the design and optimization of an oil supply system in a scroll compressor.
Deuterated potassium dihydrogen phosphate (DKDP) crystals were grown under constant temperature and supersaturation by the solution circulating method. Temperature uniformity and appropriate mass ...transfer could be easier to achieve in comparison with other crystallization systems, because the overall volume of the employed two-vessel-four-zone crystallizer was significantly reduced. Optical transmission, Raman and infrared spectra, thermal diffusivities and laser damage thresholds of both potassium dihydrogen phosphate (KDP) and DKDP crystals were measured and compared with reference data. The excellent optical properties of the DKDP crystals obtained had demonstrated that the new crystallizer design is useful for growing large DKDP crystals of good quality and with greatly reduced heavy-water consumption.
In this work we try to search for signals generated by ultra-heavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible gamma-ray by dark matter ...annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter which have low fluxes of astrophysical \(\gamma\)-ray background while large amount of dark matter. By analyzing more than 700 days observational data at LHAASO, no significant dark matter signal from 1 TeV to 1 EeV is detected. Accordingly we derive the most stringent constraints on the ultra-heavy dark matter annihilation cross-section up to EeV. The constraints on the lifetime of dark matter in decay mode are also derived.
We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and ...December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at \(3.67 \pm 0.05 \pm 0.15\) PeV. Below the knee, the spectral index is found to be -\(2.7413 \pm 0.0004 \pm 0.0050\), while above the knee, it is -\(3.128 \pm 0.005 \pm 0.027\), with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -\(0.1200 \pm 0.0003 \pm 0.0341\). This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.
A novel mesoporous SBA-15 type of hybrid material (phen−SBA-15) covalently bonded with 1,10-phenanthroline (phen) ligand was synthesized by co-condensation of tetraethoxysilane (TEOS) and the chelate ...ligand 5-N,N-bis-3-(triethoxysilyl)propylureyl-1,10-phenanthroline (phen-Si) in the presence of Pluronic P123 surfactant as a template. The preservation of the chelate ligand structure during the hydrothermal synthesis and the surfactant extraction process was confirmed by Fourier transform infrared (FTIR) and 29Si MAS NMR spectroscopies. SBA-15 consisting of the highly luminescent ternary complex Eu(TTA)3phen (TTA = 2-thenoyltrifluoroacetone) covalently bonded to a silica-based network, which was designated as Eu(TTA)3phen−SBA-15, was obtained by introducing the Eu(TTA)3·2H2O complex into the hybrid materials via a ligand exchange reaction. XRD, TEM, and N2 adsorption measurements were employed to characterize the mesostructure of Eu(TTA)3phen−SBA-15. For comparison, SBA-15 doped with Eu(TTA)3·2H2O and Eu(TTA)3phen complexes and SBA-15 covalently bonded with a binary europium complex with phen ligand were also synthesized, and were named SBA-15/Eu(TTA)3, SBA-15/Eu(TTA)3phen, and Eu−phen−SBA-15, respectively. The detailed luminescence studies on all the materials showed that, compared with the doping sample SBA-15/Eu(TTA)3phen and binary europium complex functionalized sample Eu−phen−SBA-15, the Eu(TTA)3phen−SBA-15 mesoporous hybrid material exhibited higher luminescence intensity and emission quantum efficiency. Thermogravimetric analysis on Eu(TTA)3phen−SBA-15 demonstrated that the thermal stability of the lanthanide complex was evidently improved as it was covalently bonded to the mesoporous SBA-15 matrix.
The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data ...recorded by the EDs and MDs are used to reconstruct primary information of cosmic ray and gamma-ray showers. This information is used for physical analysis in gamma-ray astronomy and cosmic ray physics. To ensure the reliability of the LHAASO-KM2A data, a three-level quality control system has been established. It is used to monitor the status of detector units, stability of reconstructed parameters and the performance of the array based on observations of the Crab Nebula and Moon shadow. This paper will introduce the control system and its application on the LHAASO-KM2A data collected from August 2021 to July 2023. During this period, the pointing and angular resolution of the array were stable. From the observations of the Moon shadow and Crab Nebula, the results achieved using the two methods are consistent with each other. According to the observation of the Crab Nebula at energies from 25 TeV to 100 TeV, the time averaged pointing errors are estimated to be \(-0.003^{\circ} \pm 0.005^{\circ}\) and \(0.001^{\circ} \pm 0.006^{\circ}\) in the R.A. and Dec directions, respectively.
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