The Molecular Pathogenesis of Pituitary Adenomas: An Update

Pituitary tumors represent the most common intracranial neoplasms accompanying serious morbidity through mass effects and inappropriate secretion of pituitary hormones. Understanding the etiology of pituitary tumorigenesis will facilitate the development of satisfactory treatment for pituitary adenomas. Although the pathogenesis of pituitary adenomas is largely unknown, considerable evidence indicates that the pituitary tumorigenesis is a complex process involving multiple factors, including genetic and epigenetic changes. This review summarized the recent progress in the study of pituitary tumorigenesis, focusing on the role of tumor suppressor genes, oncogenes and microRNAs

Txilm: Lossy Block Compression with Salted Short Hashing

Current blockchains are restricted by the low throughput. Aimed at this problem, we propose Txilm, a protocol that compresses the size of transaction presentation in each block to save the bandwidth of the network. In this protocol, a block carries short hashes of TXIDs instead of complete transactions. Combined with the sorted transactions based on TXIDs, Txilm realizes 80 times of data size reduction compared with the original blockchains. We also evaluate the probability of hash collisions, and provide methods of resolving such collisions. Finally, we design strategies to protect against potential attacks on Txilm.Comment: 5 pages and 2 figure

Finite-Time Chaos Control of a Complex Permanent Magnet Synchronous Motor System

This paper investigates the finite-time chaos control of a permanent magnet synchronous motor system with complex variables. Based on the finite-time stability theory, two control strategies are proposed to realize stabilization of the complex permanent magnet synchronous motor system in a finite time. Two numerical simulations have been conducted to demonstrate the validity and feasibility of the theoretical analysis

Hopf Bifurcation Analysis for the van der Pol Equation with Discrete and Distributed Delays

We consider the van der Pol equation with discrete and distributed delays. Linear stability of this equation is investigated by analyzing the transcendental characteristic equation of its linearized equation. It is found that this equation undergoes a sequence of Hopf bifurcations by choosing the discrete time delay as a bifurcation parameter. In addition, the properties of Hopf bifurcation were analyzed in detail by applying the center manifold theorem and the normal form theory. Finally, some numerical simulations are performed to illustrate and verify the theoretical analysis

A new post-frac evaluation method for shale gas wells based on fracturing curves

AbstractPost-fracturing evaluation by using limited data is of great significance to continuous improvement of the fracturing programs. In this paper, a fracturing curve was divided into two stages (i.e., prepad fluid injection and main fracturing) so as to further understand the parameters of reservoirs and artificial fractures. The brittleness and plasticity of formations were qualitatively identified by use of the statistics of formation fracture frequency, and average pressure dropping range and rate during the prepad fluid injection. The composite brittleness index was quantitatively calculated by using the energy zones in the process of fracturing. It is shown from the large-scale true triaxial physical simulation results that the complexity of fractures is reflected by the pressure fluctuation frequency and amplitude in the main fracturing curve, and combined with the brittleness and plasticity of formations, the fracture morphology far away from the well can be diagnosed. Well P, a shale gas well in SE Chongqing, was taken as an example for post-fracturing evaluation. It is shown that the shale beds are of stronger heterogeneity along the extension directions of horizontal wells, and with GR 260 API as the dividing line between brittleness and plasticity in this area, complex fracture systems tend to form in brittleness-prone formations. In Well P, half of the fractures are single fractures, so it is necessary to carry out fine subsection and turnaround fracturing so as to improve development effects. This paper provides a theoretical basis for improving the fracturing well design and increasing the effective stimulated volume in this area

Nanofibrous Spongy Microspheres for the Delivery of Hypoxia-primed Human Dental Pulp Stem Cells to Regenerate Vascularized Dental Pulp

Dental pulp infection and necrosis are widespread diseases. Conventional endodontic treatments result in a devitalized and weakened tooth. In this work, we synthesized novel star-shaped polymer to self-assemble into unique nanofibrous spongy microspheres (NF-SMS), which were used to carry human dental pulp stem cells (hDPSCs) into the pulp cavity to regenerate living dental pulp tissues. It was found that NF-SMS significantly enhanced hDPSCs attachment, proliferation, odontogenic differentiation and angiogenesis, as compared to control cell carriers. Additionally, NF-SMS promoted vascular endothelial growth factor (VEGF) expression of hDPSCs in a 3D hypoxic culture. Hypoxia-primed hDPSCs/NF-SMS complexes were injected into the cleaned pulp cavities of rabbit molars for subcutaneous implantation in mice. After 4 weeks, the hypoxia group significantly enhanced angiogenesis inside the pulp chamber and promoted the formation of ondontoblast-like cells lining along the dentin-pulp interface, as compared to the control groups (hDPSCs alone group, NF-SMS alone group, and hDPSCs/NF-SMS group pre-cultured under normoxic conditions). Furthermore, in an in situ dental pulp repair model in rats, hypoxia-primed hDPSCs/NF-SMS were injected to fully fill the pulp cavity and regenerate pulp-like tissues with a rich vasculature and a histological structure similar to the native pulp

Preparation and imaging of intravascular high-frequency transducer

Intravascular ultrasound (IVUS) imaging is by far the most favorable imaging modality for coronary artery evaluation. IVUS transducer design and fabrication, a key technology for intravascular ultrasound imaging, has a significant impact on the performance of the imaging results. Herein, a 35-MHz side-looking IVUS transducer probe was developed. With a small aperture of 0.40 mm × 0.40 mm, the transducer exhibited a very wide -6 dB bandwidth of 85% and a very low insertion loss of -12 dB. Further, the in vitro IVUS imaging of a porcine coronary artery was performed to clearly display the vessel wall structure while the corresponding color-coded graph was constructed successfully to distinguish necrotic core and fibrous plaque via image processing. The results demonstrated that the imaging performance of the optimized design transducer performs favorably