224 research outputs found

    SVH-B interacts directly with p53 and suppresses the transcriptional activity of p53

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    AbstractWe previously reported that inhibition of SVH-B, a specific splicing variant of SVH, results in apoptotic cell death. In this study, we reveal that this apoptosis may be dependent on the presence of p53. Co-immunoprecipitation and GST pull-down assays have demonstrated that SVH-B directly interacts with p53. In both BEL-7404 cells and p53-null Saos-2 cells transfected with a temperature-sensitive mutant of p53, V143A, ectopically expressed SVH-B suppresses the transcriptional activity of p53, and suppression of SVH by RNA interference increases the transcriptional activity of p53. Our results suggested the function of SVH-B in accelerating growth and inhibition of apoptosis is related to its inhibitory binding to p53

    Optimal ultraviolet wavelength for in vivo photoacoustic imaging of cell nuclei

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    In order to image noninvasively cell nuclei in vivo without staining, we have developed ultraviolet photoacoustic microscopy (UV-PAM), in which ultraviolet light excites nucleic acids in cell nuclei to produce photoacoustic waves. Equipped with a tunable laser system, the UV-PAM was applied to in vivo imaging of cell nuclei in small animals. We found that 250 nm was the optimal wavelength for in vivo photoacoustic imaging of cell nuclei. The optimal wavelength enables UV-PAM to image cell nuclei using as little as 2 nJ laser pulse energy. Besides the optimal wavelength, application of a wavelength between 245 and 275 nm can produce in vivo images of cell nuclei with specific, positive, and high optical contrast

    In vivo imaging of cell nuclei by photoacoustic microscopy without staining

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    Ultraviolet photoacoustic microscopy (UVPAM) can image cell nuclei in vivo with high contrast and resolution noninvasively without staining. Here, we used UV light at wavelengths of 210-310 nm for excitation of DNA and RNA to produce photoacoustic waves. We applied the UVPAM to in vivo imaging of cell nuclei in mouse skin, and obtained UVPAM images of the unstained cell nuclei at wavelengths of 245-282 nm as ultrasound gel was used for acoustic coupling. The largest ratio of contrast to noise was found for the images of cell nuclei at a 250 nm wavelength

    Pharmacological Effects of Two Novel Bombesin-Like Peptides from the Skin Secretions of Chinese Piebald Odorous Frog (Odorrana schmackeri) and European Edible Frog (Pelophylax kl. esculentus) on Smooth Muscle

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    Bombesin-like peptides, which were identified from a diversity of amphibian skin secretions, have been demonstrated to possess several biological functions such as stimulation of smooth muscle contraction and regulation of food intake. Here, we report two novel bombesin-like peptides, bombesin-OS and bombesin-PE, which were isolated from Odorrana schmackeri and Pelophylax kl. esculentus, respectively. The mature peptides were identified and structurally confirmed by high performance Scliquid chromatography (HPLC) and tandem mass spectrometry (MS/MS). Subsequently, the effects of these purified chemically-synthetic peptides on smooth muscle were determined in bladder, uterus, and ileum. The synthetic replications were revealed to have significant pharmacological effects on these tissues. The EC50 values of bombesin-OS for bladder, uterus and ileum, were 10.8 nM, 33.64 nM, and 12.29 nM, respectively. Furthermore, compared with bombesin-OS, bombesin-PE showed similar contractile activity on ileum smooth muscle and uterus smooth muscle, but had a higher potency on bladder smooth muscle. The EC50 value of bombesin-OS for bladder was around 1000-fold less than that of bombesin-PE. This suggests that bombesin-OS and bombesin-PE have unique binding properties to their receptors. The precursor of bombesin-OS was homologous with that of a bombesin-like peptide, odorranain-BLP-5, and bombesin-PE belongs to the ranatensin subfamily. We identified the structure of bombesin-OS and bombesin-PE, two homologues peptides whose actions may provide a further clue in the classification of ranid frogs, also in the provision of new drugs for human health

    Reflection-mode submicron-resolution in vivo photoacoustic microscopy

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    Submicron-resolution photoacoustic microscopy (PAM) currently exists only in transmission mode, due to the technical difficulties of combining high numerical-aperture (NA) optical illumination with high NA acoustic detection. The lateral resolution of reflection-mode PAM has not reached <2  μm in the visible light range. Here we develop the first reflection-mode submicron-resolution PAM system with a new compact design. By using a parabolic mirror to focus and reflect the photoacoustic waves, sufficient signals were collected for good sensitivity without distorting the optical focusing. By imaging nanospheres and a resolution test chart, the lateral resolution was measured to be ∼0.5  μm with an optical wavelength of 532 nm, an optical NA of 0.63. The axial resolution was measured at 15 μm. Here the axial resolution was measured by a different experiment with the lateral resolution measurement. But we didn’t describe the details of axial resolution measurement due to space limit. The maximum penetration was measured at ∼0.42  mm in optical-scattering soft tissue. As a comparison, both the submicron-resolution PAM and a 2.4 μm-resolution PAM were used to image a mouse ear in vivo with the same optical wavelength and similar pulse energy. Capillaries were resolved better by the submicron-resolution PAM. Therefore, the submicron-resolution PAM is suitable for in vivo high-resolution imaging, or even subcellular imaging, of optical absorption

    A Feasibility Study of the Integration of Enhanced Oil Recovery (CO2 Flooding) with CO2 Storage in the Mature Oil Fields of the Ordos Basin, China

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    AbstractRich in energy resources, China's Ordos Basin Shares many similarities with Wyoming's Powder River Basin. As a result, the experience and expertise pertaining to energy development in the Powder River Basin should prove helpful in the Ordos Basin. The b reserves are ranked fourth. The coal deposits in the Ordos Basin account for 39 percent of total Chinese coal reserves (3.98 trillion tonnes), and six of the thirteen largest coal mines in China are located in the basin. The overlapping development of relatively new coal conversion industries with existing oil and gas industries in northern Shaanxi Province is creating an opportunity to apply the systematic approach developed in Wyoming: the integration of geological CO2 storage and CO2-EOR. The coal conversion industry (i.e., coal-to-methanol, coal-to-olefins, etc.) provides affordable, capture-ready CO2 sources for developing large-scale integrated CO2-EOR and carbon storage projects in the Ordos Basin, China. Compared with other CCUS projects, the ability to use CO2 from the coal- conversion industry for CO2-EOR and subsequent geological CO2 storage will make integrated projects in the Ordos Basin more cost-effective and technologically efficient.The low porosity, low permeability, low oil saturation, anomalously low reservoir pressure, and high reservoir heterogeneity of the target storage formations in the Ordos Basin make using CO2 for enhanced oil recovery much more challenging here than in the US. These reservoir characteristics together constitute a major reason that CO2- EOR is not widely employed in the Ordos Basin, even though sources of highly concentrated CO2 (coal conversion plants) have been available for years. Comparisons of reservoir and crude oil properties in the Ordos Basin with the current US CO2-EOR screening guidelines reveal that gravity, viscosity, crude oil composition, and formation type of the Ordos reservoirs all are favorable for CO2 miscible flooding. The major challenges in deploying EOR result from anomalously low reservoir pressure, low porosity, and higher reservoir heterogeneity

    Real-time four-dimensional optical-resolution photoacoustic microscopy with Au nanoparticle-assisted subdiffraction-limit resolution

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    Photoacoustic microscopy (PAM) offers label-free, optical absorption contrast. A high-speed, high-resolution PAM system in an inverted microscope configuration with a laser pulse repetition rate of 100,000 Hz and a stationary ultrasonic transducer was built. Four-dimensional in vivo imaging of microcirculation in mouse skin was achieved at 18 three-dimensional volumes per second with repeated two-dimensional (2D) raster scans of 100 by 50 points. The corresponding 2D B-scan (50 A-lines) frame rate was 1800 Hz, and the one-dimensional A-scan rate was 90,000 Hz. The lateral resolution is 0.23±0.03 μm for Au nanowire imaging, which is 2.0 times below the diffraction limit

    Dual-axis illumination for virtually augmenting the detection view of optical-resolution photoacoustic microscopy

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    Optical-resolution photoacoustic microscopy (OR-PAM) has demonstrated fast, label-free volumetric imaging of optical-absorption contrast within the quasiballistic regime of photon scattering. However, the limited numerical aperture of the ultrasonic transducer restricts the detectability of the photoacoustic waves, thus resulting in incomplete reconstructed features. To tackle the limited-view problem, we added an oblique illumination beam to the original coaxial optical-acoustic scheme to provide a complementary detection view. The virtual augmentation of the detection view was validated through numerical simulations and tissue-phantom experiments. More importantly, the combination of top and oblique illumination successfully imaged a mouse brain in vivo down to 1 mm in depth, showing detailed brain vasculature. Of special note, it clearly revealed the diving vessels that were long missing in images from original OR-PAM
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