[Effect of RBP2 gene silencing on proliferation, migration and invasion of ovarian epithelial cancer SKOV3/DDP cells and its mechanism].

Objective: To explore the effect of down-regulation of retinol binding protein 2 (RBP2) expression on the biological characteristics of ovarian cancer cells and its mechanism. Methods: Knockdown of RBP2 and cisplatin (DDP)-resistant ovarian cancer cell line SKOV3/DDP-RBP2i was established, the negative control group and blank control group were also set. Cell counting kit 8 (CCK-8) was used to detect the cell proliferation ability, flow cytometry was used to detect cell apoptosis, scratch test and Transwell invasion test were used to detect cell migration and invasion ability, real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) and western blot were used to detect the expressions of molecular markers related to epithelial-mesenchymal transition (EMT). The effect of RBP2 on the growth of ovarian cancer was verified through experiment of transplanted tumors in nude mice, and the relationships between RBP2 expression and tumor metastasis and patient prognosis were analyzed using the clinical data of ovarian cancer in TCGA database. Results: After down-regulating the expression of RBP2, the proliferation ability of SKOV3/DDP cell was significantly reduced. On the fifth day, the proliferation activities of SKOV3/DDP-RBP2i group, negative control group and blank control group were (56.67±4.16)%, (84.67±3.51) and (87.00±4.00)% respectively, with statistically significant difference (P<0.001). The apoptosis rate of SKOV3/DDP-RBP2i group was (14.19±1.50)%, higher than (8.77±0.75)% of the negative control group and (7.48±0.52)% of the blank control group (P<0.001). The number of invasive cells of SKOV3/DDP-RBP2i group was (55.20±2.39), lower than (82.60±5.18) and (80.80±7.26) of the negative control group and the blank control group, respectively (P<0.001). The scratch healing rate of SKOV3/DDP-RBP2i group was (28.47±2.72)%, lower than (50.58±4.06)% and (48.92±4.63)% of the negative control group and the blank control group, respectively (P<0.001). The mRNA and protein expressions of E-cadherin in the SKOV3/DDP-RBP2i group were higher than those in the negative control group (P=0.015, P<0.001) and the blank control group (P=0.006, P<0.001). The mRNA and protein expression of N-cadherin in SKOV3/DDP-RBP2i group were lower than those in the negative control group (P=0.012, P<0.001) and the blank control group (P=0.005, P<0.001). The mRNA and protein expressions of vimentin in SKOV3/DDP-RBP2i group were also lower than those in the negative control group (P=0.016, P=0.001) and the blank control group (P=0.011, P=0.001). Five weeks after the cells inoculated into the nude mice, the tumor volume of SKOV3/DDP-RBP2i group, negative control group and blank control group were statistically significant different. The tumor volume of SKOV3/DDP-RBP2i group was smaller than those of negative control group and blank control group (P=0.001). Bioinformatics analysis showed that the expression of RBP2 in patients with metastatic ovarian cancer was higher than that without metastasis (P=0.043), and the median overall survival of ovarian cancer patients with high RBP2 expression was 41 months, shorter than 69 months of low RBP2 expression patients (P<0.001). Conclusion: Downregulation of the expression of RBP2 in SKOV3/DDP cells can inhibit cell migration and invasion, and the mechanism may be related to the inhibition of EMT.

Hydroxytyrosol inhibits apoptosis in ischemia/reperfusion-induced acute kidney injury via activating Sonic Hedgehog signaling pathway.

OBJECTIVE: Acute kidney injury (AKI) is a common critical illness in clinic, which seriously threatens the life of patients. The aim of this study was to validate the anti-apoptotic effect of hydroxytyrosol (HT) in ischemia/reperfusion (I/R)-induced AKI. MATERIALS AND METHODS: The cell model of AKI was established by hypoxia/reoxygenation (H/R), and the animal model of AKI was established by I/R. The apoptosis was observed by Caspase-3 activity assay, flow cytometry and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining. Cell viability was detected by cell counting kit-8 (CCK-8) assay. Protein expression was measured by Western blot and mRNA level was analyzed by quantitative real-time polymerase chain reaction (RT-PCR). Renal function was assessed by measuring serum creatinine (Cr) and blood urea nitrogen (BUN). RESULTS: H/R induced apoptosis of HK-2 cells and reduced cell viability. When HK-2 cells were pretreated with HT, apoptosis was markedly inhibited, and cell viability was greatly increased. In addition, HT could inhibit I/R-induced apoptosis of rat kidney cells and could notably improve rat kidney function. H/R promoted Sonic Hedgehog (SHH) expression in HK-2 cells, while HT treatment further enhanced SHH expression. Similarly, I/R induces SHH expression in kidney tissue, and HT could further promote SHH expression. CONCLUSIONS: These results indicated that HT could inhibit apoptosis in I/R-induced AKI via activating SHH signaling pathway.

[Expression of tropomyosin 2 in aortic dissection tissue].

Objective: To investigate the expression pattern of tropomyosin 2(TPM2) in aorta of patients with aortic dissection and explore its clinical implication. Methods: Thirteen cases with acute type A aortic dissection(TAAD) diagnosed by transabdominal aortic angiography from 2015 in Tongji Hospital were included. During the operation, the aortic wall tissues of these patients were collected. Ten patients with heart transplantation were selected as control group, and normal aortic wall tissues were taken. The hematoxylin-eosin (HE) and Verhoeff's Van Gieson (EVG) staining were performed to observe the morphological changes of aorta. The mRNA expression level of TPM2 was measured by real-time fluorescent quantitative-PCR, and the protein levels of TPM2 were detected by Western blot and immunohistochemical staining. Image The J software was used to collect the optical density values of each point on the image, obtain the integrated optical density(IOD) value, and calculate the average density(%, IOD/area of the target distribution area). Results: HE and EVG staining revealed medial degeneration and broken elastic fiber in aorta of TAAD patients. The mRNA expression levels of TPM2 were significantly upregulated in aorta of TAAD patients as compared to the control group (P<0.05), so as the TPM2 protein expression levels ((9.73±1.20)% vs. (0.11±0.04)%, P<0.05). And TPM2 was mainly expressed in cytoplasm. Conclusion: The increased expression of TPM2 in TAAD patients hints that TPM2 might be involved in the pathogenesis of aortic dissection.

Performance of InGaN based green laser diodes improved by using an asymmetric InGaN/InGaN multi-quantum well active region.

Series of green laser diodes (LDs) with different (In)GaN barrier layers are investigated. It is found that the optical confinement factor of multi-quantum well (MQW) always increases with increasing indium content of InGaN barrier layer, which results in a decrease of threshold current when indium content of InGaN barrier layer increases from 0 to 5%. However, when a high In content InGaN barrier is used (> 5%), both threshold current and slop efficiency of LDs deteriorate. It may be attributed to the waste of carriers in the potential well at the interface between the last barrier (LB) and the upper waveguide (UWG) layers, which is induced by the piezoelectric polarization effect in high In content InGaN LB layer. Therefore, a new LD structure using a thin thickness of the LB layer to reduce the effect of polarization shows a low threshold current and a high output power even when the In content of barrier layers is as large as 7%.

High-performance temperature sensing using a selectively filled solid-core photonic crystal fiber with a central air-bore.

A high-performance temperature sensor based on mode-coupling principle is proposed using a selectively filled, solid-core photonic crystal fiber with a central air-bore. The fibers are fabricated using the "stack-and-draw" method, with a micro scale central bore deliberately kept during the drawing procedure. The addition of the central air-bore enhances the mode-coupling efficiency between the fundamental core mode and modes in the high-index liquid-filled holes in the fiber cladding, therefore, the fiber can be used for a novel sensing architecture, when cladding holes are selectively filled with temperature sensitive liquids. Based on this concept, numerical analyses are accomplished using finite element method, showing that this fiber-based temperature sensor possesses high sensitivity of -6.02 nm/°C, with a resolution of 3.32 × 10-3 °C, in the temperature range from -80 to 90 °C. The selective hole-filling is verified by a multi-step infiltration technique. A particularly designed probe with improved sensitivity and manipulation is also proposed for this system.

Evolution of differential efficiency in blue InGaN laser diodes before and after a lasing threshold.

The optical power emitting from the cavity facet of blue InGaN-based laser diodes (LDs) is measured to investigate the efficiency droop. The efficiency droop behavior of blue InGaN-based LDs near the threshold is confirmed in our experiments. From measurements of optical power at different wavelengths, it is analyzed that the droop behavior of LDs can be ascribed to the efficiency reduction of longer wavelengths. The efficiency of longer wavelengths is subject to the carrier occupation process in quantum levels. In addition, it is found that the droop behavior may be largely affected by the relatively large threshold current of InGaN-based LDs and the screening effect of polarization, and it can be suppressed by stimulated emission.

Investigation on the corrosive effect of NH3 during InGaN/GaN multi-quantum well growth in light emitting diodes.

Three series of samples with different NH3 flow rate are grown and the optical and structural properties are investigated. It is found that apart from a positive effect on keeping a high partial pressure of nitrogen to enhance indium incorporation, NH3 may also play a negative effect on indium incorporation during InGaN growth. Especially, when temperature is relatively high, the hydrogen generated from the dissociation of NH3 may suppress the chemical reaction which produces InN, leading to a reduced indium incorporation efficiency during the InGaN layer growth.

Emission efficiency enhanced by reducing the concentration of residual carbon impurities in InGaN/GaN multiple quantum well light emitting diodes.

A series of samples with varying growth pressure are grown and their optical and structural properties are investigated. It is found that the residual carbon concentration decreases when the reactor pressure increases from 80 to 450 Torr during the InGaN/GaN multiple quantum well growth. It results in an enhanced peak intensity of electroluminescence because carbon impurities can induce deep energy levels and act as non-radiative recombination centers in InGaN layers.

A dynamic model for the outbreaks of hand, foot, and mouth disease in Taiwan.

The first large outbreak of hand, foot, and mouth disease (HFMD) with severe complications primarily caused by enterovirus 71 was reported in Taiwan in 1998. Surveillance of HFMD to evaluate the spread of HFMD with and without infection control policy is needed. We developed a new dynamic epidemic Susceptible-Infected-Recovered (SIR) model to fit the surveillance data on containing valuable information on the severity of HFMD in order to accurately estimate the basic reproductive number (R 0) of HFMD. After fitting the empirical data, in conjunction with other relevant parameters extracted from the literature, the estimated transmission coefficients were close to 5 × 10-7 (per day) and the proportion of severe HFMD cases ranged between 0 and 0·0036 (per day). Taking into account the distribution of all parameters considered in our dynamic epidemic model, the R 0 computed was 1·37 (95% confidence interval 0·24-5·84), suggesting a higher likelihood of the spread of HFMD if no infection control policy is provided. The isolation strategy against the spread of HFMD not only delayed the epidemic peak with the delayed time ranging from 4 weeks for only 20% isolation to 47 weeks for 100% isolation but also reduced total number of HFMD cases with the percentage of reduction ranging from 1·3% for only 20% isolation to 13·3% for 100% isolation. The proposed model can also be flexible for evaluating the effectiveness of two other possible policies for containing HFMD, quarantine and vaccination (if the vaccine can be developed).

Differential resistance of GaN-based laser diodes with and without polarization effect.

In this paper, we used numerical calculation and simulation to investigate the differential resistance of GaN-based laser diodes (LDs) with and without polarization effect. We confirmed the existence of a kink at the vicinity of threshold current in the differential resistance curve of GaN-based LDs and found that the kink polarity can be reversed dependent on the polarization effect. The serial parasitic diodes should be included in the theoretical analysis of the equivalent circuit of the LD devices. We determined that the superposition effects of the n-side, active, and p-side regions of the LDs caused the kink and its polarity. We also found that the differential resistance before and after the threshold was dominated by the p-side region and its gradual reduction is related to an electron overflow into p-side. Finally, we studied the effects of cavity facet reflectivity on the kink.

Temperature dependence of photoluminescence spectra for green light emission from InGaN/GaN multiple wells.

Three green light emitting InGaN/GaN multiple quantum well (MQW) structures with different In composition grown by metal-organic chemical vapor deposition are investigated by the X-ray diffraction and the temperature-dependent photoluminescence (PL) measurements. It is found that when the In composition increases in the InGaN/GaN MQWs, the PL spectral bandwidth may anomalously decrease with increasing temperature. The reduction of PL spectral bandwidth may be ascribed to the enhanced non-radiative recombination process which may lower the light emission efficiency of the localized luminescent centers with shallow localization energy in the high-In-content InGaN quantum wells and also cause a reduction of integrated PL intensity.

TRAF1 is a key mediator for hepatic ischemia/reperfusion injury.

Tumor necrosis factor receptor-associated factor 1 (TRAF1), an adapter in signal transduction, is involved in immunity and in apoptotic processes in various cell types. However, little is known about its function and the molecular mechanism of its activation during liver injury. This study tested the hypothesis that TRAF1 is a mediator of cell injury after hepatic ischemia/reperfusion injury (I/R). In a mouse hepatic I/R injury model, we found that TRAF1 expression was highly induced. TRAF1 deficiency was liver protective, whereas sustained TRAF1 overexpression aggravated liver injury in response to hepatic I/R injury. Mechanistic studies demonstrated that a deficiency of TRAF1 in cultured hepatocytes led to the inhibition of NF-κB-mediated inflammatory responses, suppression of the ASK/JNK pro-death pathway and promotion of cellular regeneration capacity. In contrast, the converse occurred in hepatocyte-specific TRAF1 transgenic mice. TRAF1 activated the ASK1/JNK pathway and promoted hepatic injury. Our study demonstrates that TRAF1 is a crucial early mediator of hepatic I/R injury and suggests that TRAF1 may be a potential gene therapy target for the treatment of liver injury.

Suppression of electron leakage by inserting a thin undoped InGaN layer prior to electron blocking layer in InGaN-based blue-violet laser diodes.

InGaN-based blue-violet laser diodes (LDs) suffer from electron leakage into the p-type regions, which could be only partially alleviated by employing the electron blocking layer (EBL). Here, a thin undoped InGaN interlayer prior to EBL is proposed to create an additional forbidden energy range above the natural conduction band edge, which further suppresses the electron leakage and thus improve the characteristics of LDs. Numerical device simulations reveal that when the proper composition and thickness of InGaN interlayer are chosen, the electron leakage could be efficiently eliminated without inducing any severe accumulation of electrons at the interlayer, resulting in a maximum output power of the device.

IRF4 is a novel mediator for neuronal survival in ischaemic stroke.

Neuroprotection following ischaemic stroke is driven by the interplay between regulatory transcription factors and endogenous protective factors. IRF4, a member of the interferon regulatory factor (IRF) family, is implicated in the survival of tumour cells. However, its role in the survival of normal cells including neurons remains elusive. Using genetic approaches, we established a central role for IRF4 in protection against ischaemia/reperfusion (I/R)-induced neuronal death. IRF4 was expressed in neurons, and induced by ischaemic stroke. Neuron-specific IRF4 transgenic (IRF4-TG) mice exhibited reduced infarct lesions, and this effect was reversed in IRF4-knockout mice. Notably, we revealed that IRF4 rescues neurons from I/R-induced death both in vivo and in vitro. Integrative transcriptional and cell survival analyses showed that IRF4 functions mechanistically as a transcription activator of serum response factor (SRF) crucial to salvage neurons during stroke. Indeed, the expression of SRF and SRF-dependent molecules was significantly upregulated upon IRF4 overexpression and conversely inhibited upon IRF4 ablation. Similar results were observed in oxygen glucose deprivation (OGD)-treated primary cortical neurons. Furthermore, we identified the IRF4-binding site in the promoter region of the SRF gene essential for its transcription. To verify the IRF4-SRF axis in vivo, we generated neuron-specific SRF knockout mice, in which SRF exerted profound cerebroprotective effects similar to those of IRF4. More importantly, the phenotype observed in IRF4-TG mice was completely reversed by SRF ablation. Thus, we have shown that the IRF4-SRF axis is a novel signalling pathway critical for neuronal survival in the setting of ischaemic stroke.

Single-photon property characterization of 1.3 µm emissions from InAs/GaAs quantum dots using silicon avalanche photodiodes.

We developed a new approach to test the single-photon emissions of semiconductor quantum dots (QDs) in the optical communication band. A diamond-anvil cell pressure device was used for blue-shifting the 1.3 µm emissions of InAs/GaAs QDs to 0.9 µm for detection by silicon avalanche photodiodes. The obtained g((2))(0) values from the second-order autocorrelation function measurements of several QD emissions at 6.58 GPa were less than 0.3, indicating that this approach provides a convenient and efficient method of characterizing 1.3 µm single-photon source based on semiconductor materials.

Al compositional inhomogeneity of AlGaN epilayer with a high Al composition grown by metal-organic chemical vapour deposition.

The Al compositional distribution of AlGaN is investigated by cathodoluminescence (CL). Monochromatic CL images and CL spectra reveal a lateral Al compositional inhomogeneity, which corresponds to surface hexagonal patterns. Cross-sectional CL images show a relatively uniform Al compositional distribution in the growth direction, indicating columnar growth mode of AlGaN films. In addition, a thin AlGaN layer with lower Al composition is grown on top of the buffer AlN layer near the bottom of the AlGaN epilayer because of the larger lateral mobility of Ga adatoms on the growth surface and their accumulation at the grain boundaries.

Genetic diversity of noroviruses in Taiwan between November 2004 and March 2005.

Noroviruses are a major health burden and are responsible for the majority of outbreaks of gastroenteritis in the world. Human noroviruses can be genetically divided into two main genogroups (GI and GII) and subdivided into many genotypes. In this study, stool specimens collected from 12 outbreaks of gastroenteritis in Taiwan were screened for viral agents between the 23rd of November 2004 and 9th of March 2005. Noroviruses were detected in all outbreaks. We detected six different norovirus genotypes: GI/11, GI/14, GII/3, GII/4, GII/6, and GII/18. Noroviruses belonging to GII/4 were dominant, 50 of 60 (83%) sequences, and were detected in 10 of 12 outbreaks. Furthermore, the norovirus GII/4 strains were detected throughout Taiwan, demonstrating their widespread distribution. We also found that three outbreaks had noroviruses from multiple genotypes. Our results have shown for the first time that noroviruses are an important cause of gastroenteritis in Taiwan.