361 research outputs found
Specific Targeting MRI of Chitosan Oligosaccharide Modified Fe3O4 Nanoprobe on Macrophage and the Inhibition of Macrophage Foaming Induced by ox-LDL
Atherosclerosis (AS) is a primary cause of morbidity and mortality all over the world. Molecular imaging techniques can enable early localization and diagnosis of atherosclerosis plaques. Recent newly developed chitooligosaccharides (CSO) is considered to be capable of target mannose receptors on the surface of macrophages and to inhibit foam cell formation. Here we present a targeting magnetic resonance imaging (MRI) nanoprobe, which was successfully constructed with polyacrylic acid (PAA) modified nanometer iron oxide (Fe3O4) as the core, and coating with CSO molecules, possessing the abilities of targeted MRI and specifically inhibition of the formation of foamy macrophages in the atherosclerotic process. The experimental results showed that the distributions of PAA-Fe3O4 and CSO-PAA-Fe3O4 were uniform and the corresponding sizes were about 5.93 nm and 8.15 nm, respectively. The Fourier transform infrared spectra (FTIR) testified the CSO was coupled with PAA-Fe3O4 successfully. After coupled with CSO, the r1 of PAA-Fe3O4 was increased from 5.317 mM s-1 to 6.147 mM s-1, indicating their potential as MRI contrast agent. Oil Red O staining and total cholesterols (TC) determination showed that CSO-PAA-Fe3O4 could significantly inhibit the foaming process of RAW264.7 cells induced by oxidatively modified low density lipoprotein (ox-LDL). In vitro cellular MRI displayed that, compared with PAA-Fe3O4,CSO-PAA-Fe3O4 could lower the T1 relaxation time of RAW264.7 cells better. In summary, construction of CSO-PAA-Fe3O4 nanoprobe in this study could realize the targeted MRI of macrophages and inhibition of ox-LDL induced macrophage foaming process. This will provide a new avenue in the diagnosis and treatment of AS
Engineering ferroelectricity in monoclinic hafnia
Ferroelectricity in the complementary metal-oxide semiconductor
(CMOS)-compatible hafnia (HfO) is crucial for the fabrication of
high-integration nonvolatile memory devices. However, the capture of
ferroelectricity in HfO requires the stabilization of
thermodynamically-metastable orthorhombic or rhombohedral phases, which entails
the introduction of defects (e.g., dopants and vacancies) and pays the price of
crystal imperfections, causing unpleasant wake-up and fatigue effects. Here, we
report a theoretical strategy on the realization of robust ferroelectricity in
HfO-based ferroelectrics by designing a series of epitaxial
(HfO)/(CeO) superlattices. The advantages of the designated
ferroelectric superlattices are defects free, and most importantly, on the base
of the thermodynamically stable monoclinic phase of HfO. Consequently, this
allows the creation of superior ferroelectric properties with an electric
polarization 25 C/cm and an ultralow polarization-switching energy
barrier at 2.5 meV/atom. Our work may open an entirely new route towards
the fabrication of high-performance HfO based ferroelectric devices
MiT family translocation renal cell carcinoma with retroperitoneal metastasis in childhood: a case report
RCC accounts for only 0.1%–0.3% of all kidney tumors and 2%–6% of malignant kidney tumors in children. Accounting for approximately one-third of the total number of cases in children and adolescents with RCC, Xp11.2 tRCC is the most common subtype of the MiT family translocation renal cell carcinoma, which is a group of rare childhood and adult tumors, characterized by recurrent gene rearrangements of TFE3. Here we report a rare case of a 6-year-old male patient with MiT family translocation renal cell carcinoma (MiTF tRCC) where the patient developed retroperitoneal metastasis. The patient underwent partial nephrectomy (PN), radical nephrectomy (RN), abdominal lymph node resection, and intestinal adhesion lysis. Microscopically, we detected focal and nest clump-shaped clusters of tumor cells whose cytoplasm was bright and clear. Immunohistochemistry (IHC) showed tumor cells diffusely expressed TFE3, and fluorescence in situ hybridization (FISH) demonstrated disruption of the TFE3 locus, confirming the diagnosis of Xp11.2 tRCC, the most common subtype of MiTF tRCC. Eventually, the patient obtained a good therapeutic result. This case can provide a good reference and guidance for pediatric urologists and oncologists to recognize and diagnose rare renal cell carcinoma in children
High-voltage vertical Ga\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e power rectifiers operational at high temperatures up to 600 K
This work presents the temperature-dependent forward conduction and reverse blocking characteristics of a high-voltage vertical Ga2O3 power rectifier from 300 K to 600 K. Vertical β-Ga2O3 Schottky barrier diodes (SBDs) were fabricated with a bevel-field-plated edge termination, where a beveled sidewall was implemented in both the mesa and the field plate oxide. The Schottky barrier height was found to increase from 1.2 eV to 1.3 eV as the temperature increases from 300 K to 600 K, indicating the existence of barrier height inhomogeneity. The net donor concentration in the drift region shows little dependence on the temperature. The reverse leakage current up to 500 V was found to be limited by both the thermionic-field electron injection at the Schottky contact and the electron hopping via the defect states in the depletion region. At 300-500 K, the leakage is first limited by the electron injection at low voltages and then by the hopping in depleted Ga2O3 at high voltages. At temperatures above 500 K, the thermionic field emission limits the device leakage over the entire voltage range up to 500 V. Compared to the state-of-the-art SiC and GaN SBDs when blocking a similar voltage, our vertical Ga2O3 SBDs are capable of operating at significantly higher temperatures and show a smaller leakage current increase with temperature. This shows the great potential of Ga2O3 SBDs for high-temperature and high-voltage power applications
Research on Infection and Toxin Producing Mechanism of Postharvest penicillium in Citrus
Citrus fruits are the largest fruit crop in China. Post-harvest green mold is one of the major diseases that affect the quality and safety of citrus fruits, as it poses a risk of mycotoxins contamination. Current research primarily focuses on the infection mechanism of Penicillium digitatum, while other important Penicillium plays a significant role in citrus infection and toxin production. The mycotoxins produced can pose a serious threat to food safety. In this review, we provide an overview of the infection and toxin producing mechanisms of the main green mold fungi affecting citrus post-harvest, analyze the current research trends and directions in the field of citrus green mold disease, aiming to reduce the risk of fungal toxin contamination and promote quality improvement and efficiency in the citrus industry, providing new research perspectives for enhancing citrus quality and supporting industry development
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