90 research outputs found

    Involvement of the JNK/FOXO3a/Bim Pathway in Neuronal Apoptosis after Hypoxic-Ischemic Brain Damage in Neonatal Rats.

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    c-Jun N-terminal kinase (JNK) plays a key role in the regulation of neuronal apoptosis. Previous studies have revealed that forkhead transcription factor (FOXO3a) is a critical effector of JNK-mediated tumor suppression. However, it is not clear whether the JNK/FOXO3a pathway is involved in neuronal apoptosis in the developing rat brain after hypoxia-ischemia (HI). In this study, we generated an HI model using postnatal day 7 rats. Fluorescence immunolabeling and Western blot assays were used to detect the distribution and expression of total and phosphorylated JNK and FOXO3a and the pro-apoptotic proteins Bim and CC3. We found that JNK phosphorylation was accompanied by FOXO3a dephosphorylation, which induced FOXO3a translocation into the nucleus, resulting in the upregulation of levels of Bim and CC3 proteins. Furthermore, we found that JNK inhibition by AS601245, a specific JNK inhibitor, significantly increased FOXO3a phosphorylation, which attenuated FOXO3a translocation into the nucleus after HI. Moreover, JNK inhibition downregulated levels of Bim and CC3 proteins, attenuated neuronal apoptosis and reduced brain infarct volume in the developing rat brain. Our findings suggest that the JNK/FOXO3a/Bim pathway is involved in neuronal apoptosis in the developing rat brain after HI. Agents targeting JNK may offer promise for rescuing neurons from HI-induced damage

    Retroperitoneal neuroglial heterotopia: a case report and literature review

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    BackgroundNeuroglial heterotopia is a rare lesion composed of differentiated neuroectodermal cells that manifest in extracranial locations, with the majority of cases predominantly occurring in the head and neck region. Retroperitoneal neuroglial heterotopia is exceptionally rare, with isolated cases published in the scientific literature.Case reportHere, we present the case of a 3-year-old girl who was admitted without clinical signs but presented with a palpable abdominal mass. Ultrasonography and computed tomography scans revealed a sizable cystic lesion within the retroperitoneal space. Subsequently, laparoscopic resection was performed. Histological examination unveiled neuroglial cell-lined cysts encompassing fibrous connective tissue, ganglia, glial tissue, and nerve bundles. Notably, distinct areas and cell types exhibited expression of S100, glial fibrillary acidic protein, and neuron-specific enolase. Follow-up assessments revealed no relapses or late complications.ConclusionIn cases of retroperitoneal neuroglial heterotopia, most children may remain asymptomatic without any congenital anomalies. Despite their detectability through imaging, accurate preoperative diagnosis is seldom achieved. Generally, a favorable prognosis follows complete surgical resection, although further cases are required to confirm its long-term efficacy, necessitating extended follow-up for verification

    DNA-Interacting Characteristics of the Archaeal Rudiviral Protein SIRV2_Gp1

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    Whereas the infection cycles of many bacterial and eukaryotic viruses have been characterized in detail, those of archaeal viruses remain largely unexplored. Recently, studies on a few model archaeal viruses such as SIRV2 (Sulfolobus islandicus rod-shaped virus) have revealed an unusual lysis mechanism that involves the formation of pyramidal egress structures on the host cell surface. To expand understanding of the infection cycle of SIRV2, we aimed to functionally characterize gp1, which is a SIRV2 gene with unknown function. The SIRV2_Gp1 protein is highly expressed during early stages of infection and it is the only protein that is encoded twice on the viral genome. It harbours a helix-turn-helix motif and was therefore hypothesized to bind DNA. The DNA-binding behavior of SIRV2_Gp1 was characterized with electrophoretic mobility shift assays and atomic force microscopy. We provide evidence that the protein interacts with DNA and that it forms large aggregates, thereby causing extreme condensation of the DNA. Furthermore, the N-terminal domain of the protein mediates toxicity to the viral host Sulfolobus. Our findings may lead to biotechnological applications, such as the development of a toxic peptide for the containment of pathogenic bacteria, and add to our understanding of the Rudiviral infection cycle.status: publishe

    Highly sensitive temperature sensing based on all-solid cladding dual-core photonic crystal fiber filled with the toluene and ethanol

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    An all-solid cladding dual-core photonic crystal fiber (DC-PCF) filled with toluene and ethanol is proposed for the temperature sensing. The all-solid cladding is formed by using the fluorine-doped silica glass instead of the air holes in the cladding region. By selectively filling the toluene and ethanol into the three air holes near the core region, the characteristic of the temperature sensing is numerically investigated. The simulation results show that the average sensitivity of the temperature sensing can achieve −11.64 and −7.41 nm/°C in the temperature ranges from 0 to 70 °C and −80 to 0 °C, respectively, when the length of the DC-PCF is as short as 1.6 mm. The maximum sensitivity in the considered temperature ranges can be up to −15 and −9 nm/°C, respectively. Moreover, the proposed temperature sensor is insensitive to the hydrostatic pressure

    Mid-Infrared Silicon Photonic Crystal Fiber Polarization Filter Based on Surface Plasmon Resonance Effect

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    In this paper, a novel silicon photonic crystal fiber (Si-PCF) polarization filter based on surface plasmon resonance effect is proposed for the first time. With the full-vector finite-element method, the mode coupling characteristics of the Si-PCF with the gold-coated film between the core mode and surface plasmonpolariton mode are investigated, and the confinement losses are analyzed. The confinement losses of the Y-polarized core mode at the three resonant wavelengths 2.84, 3.29, and 4.53 μm are 9235.9, 27097.5, and 97818.3 dB/m, respectively. The extinction ratio reaches -391 dB and the insertion loss is less than 1 dB when the Si-PCF length is 4 mm, along with the filter bandwidth of 2.75 μm. Moreover, by modifying the fiber structure parameters, the filter bandwidth of the proposed three kinds of Si-PCF polarization filters can cover 2.75 to 7.80 μm. It is believed that the proposed Si-PCF polarization filter has important applications in the mid-infrared laser and optical communication systems

    Design of diamond-shape photonic crystal fiber polarization filter based on surface plasma resonance effect

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    A novel plasmonic polarization filter based on the diamond-shape photonic crystal fiber (PCF) is proposed. The resonant coupling characteristics of the PCF polarization filter are investigated by the full-vector finite-element method. By optimizing the geometric parameters of the PCF, when the fiber length is 5 mm, the polarization filter has a bandwidth of 990 nm and an extinction ratio (ER) of lower than -20 dB. Moreover, a single wavelength polarization filter can also be achieved, along with an ER of -279.78 dB at wavelength 1.55 μm. It is believed that the proposed PCF polarization filter will be very useful in laser and optical communication systems

    Surface Plasmon Resonance-Based Silicon Dual-Core Photonic Crystal Fiber Polarization Beam Splitter at Mid-Infrared Spectral Region

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    In this paper, a novel silicon dual-core photonic crystal fiber (Si-DC-PCF) polarization beam splitter (PBS) based on surface plasmon resonance effect is proposed. The mode coupling characteristics between the X and Y-polarized even and odd modes and surface plasmon polariton mode are analyzed by using the finite element method and coupled-mode theory. The influences of the structure parameters of the Si-DC-PCF on the coupling length and coupling length ratio are investigated. The normalized output power of the X and Y-polarized modes in the cores A and B and the corresponding extinction ratio are also discussed. By optimizing the structure parameters of the Si-DC-PCF, the PBS length of 192 μm and bandwidth of 830 and 730 nm in the cores A and B are achieved. It is believed that the proposed Si-DC-PCF PBS can find important applications in the mid-infrared laser and sensing systems

    Ultra-short polarization beam splitter based on dual-core photonic crystal fiber with surface plasmon resonance effect

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    An ultra-short polarization beam splitter (PBS) based on a dual-core photonic crystal fiber (PCF) with the surface plasmon resonance effect is proposed. The finite-element method is used to investigate the coupling characteristics between the core mode and surface plasmon polariton mode. The influences of the PCF structure parameters on the coupling length and coupling length ratio are also investigated. The normalized output powers of the x-polarization and y-polarization are calculated, and the optimized PBS achieves an ultra-short length of 62.5  μm. The splitting bandwidth of 110 nm (1.51 to 1.61  μm) is achieved when the extinction ratio (ER) is less than −20  dB. The minimum ER reaches −71  dB at the wavelength of 1.55  μm. The proposed PBS has an important application in high-speed optical communication systems

    A Surface Plasmon Resonance-Based Photonic Crystal Fiber Sensor for Simultaneously Measuring the Refractive Index and Temperature

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    In this paper, a surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) sensor is proposed for simultaneously measuring the refractive index (RI) and temperature. In the design, the central air hole and external surface of the proposed PCF are coated with gold films, and an air hole is filled with the temperature-sensitive material (TSM). By introducing the inner and outer gold films and TSM, the RI and temperature can be measured simultaneously at different wavelength regions. The simulation results show that the average wavelength sensitivities of the proposed SPR-based PCF sensor can reach 4520 nm/RIU and 4.83 nm/°C in the RI range of 1.35~1.40 and a temperature range of 20~60 °C, respectively. Moreover, because of using the different wavelength regions for sensing, the RI and temperature detections of the proposed SPR-based PCF sensor can be achieved independently. It is believed that the proposed SPR-based PCF RI and temperature sensor has important applications in biomedicine and in environmental science
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