Level Set Based Hippocampus Segmentation in MR Images with Improved Initialization Using Region Growing

The hippocampus has been known as one of the most important structures referred to as Alzheimer’s disease and other neurological disorders. However, segmentation of the hippocampus from MR images is still a challenging task due to its small size, complex shape, low contrast, and discontinuous boundaries. For the accurate and efficient detection of the hippocampus, a new image segmentation method based on adaptive region growing and level set algorithm is proposed. Firstly, adaptive region growing and morphological operations are performed in the target regions and its output is used for the initial contour of level set evolution method. Then, an improved edge-based level set method utilizing global Gaussian distributions with different means and variances is developed to implement the accurate segmentation. Finally, gradient descent method is adopted to get the minimization of the energy equation. As proved by experiment results, the proposed method can ideally extract the contours of the hippocampus that are very close to manual segmentation drawn by specialists

A Single E627K Mutation in the PB2 Protein of H9N2 Avian Influenza Virus Increases Virulence by Inducing Higher Glucocorticoids (GCs) Level

While repeated infection of humans and enhanced replication and transmission in mice has attracted more attention to it, the pathogenesis of H9N2 virus was less known in mice. PB2 residue 627 as the virulent determinant of H5N1 virus is associated with systemic infection and impaired TCR activation, but the impact of this position in H9N2 virus on the host immune response has not been evaluated. In this study, we quantified the cellular immune response to infection in the mouse lung and demonstrate that VK627 and rTsE627K infection caused a significant reduction in the numbers of T cells and inflammatory cells (Macrophage, Neutrophils, Dendritic cells) compared to mice infected with rVK627E and TsE627. Further, we discovered (i) a high level of thymocyte apoptosis resulted in impaired T cell development, which led to the reduced amount of mature T cells into lung, and (ii) the reduced inflammatory cells entering into lung was attributed to the diminished levels in pro-inflammatory cytokines and chemokines. Thereafter, we recognized that higher GCs level in plasma induced by VK627 and rTsE627K infection was associated with the increased apoptosis in thymus and the reduced pro-inflammatory cytokines and chemokines levels in lung. These data demonstrated that VK627 and rTsE627K infection contributing to higher GCs level would decrease the magnitude of antiviral response in lung, which may be offered as a novel mechanism of enhanced pathogenicity for H9N2 AIV

Improved algorithm for determining cable saddle pre-offsets considering the coupling effect of tower and splay saddles

Abstract By analysing the mechanical and geometrical relations between the main cable, tower, and splay saddles, and considering the coupling effect of the tower and splay saddles, an improved algorithm is proposed to determine the cable saddles pre-offsets of suspension bridges. The equilibrium relationship of the cable saddles, the compatible deformation condition, and the basic equation of the main cable shape are considered to establish several coupled non-linear equations up to 19, and the tower and splay saddle pre-offsets are obtained by solving the above equations with the Newton–Raphson method. This paper presents the initial value selection principle and the constraint conditions for solving the cable saddle pre-offsets of the plane cable suspension bridge and the calculation process ensures convergence. The calculation example demonstrates that the improved algorithm without an exact initial value can achieve excellent convergence

TinyPairing: Computing Tate Pairing on Sensor Nodes with Higher Speed and Less Memory

Since the introduction of bilinear pairing to public key cryptography in 2001, pairing has been considered as one of the most expensive public key operations in terms of both computational complexity and memory requirement. Recently some work has been done on improving the computation time of pairing on resource-constrained wireless sensors. However, little has been focused on reducing the memory consumption. In this paper, we propose three new algorithms for speeding up the computation and reducing the memory footprint of cubing, modular reduction and polynomial multiplication in ηT pairing over finite fields of characteristic three. We further propose new programming techniques for making the implementation even more lightweight. Our experimental results show that one ηT pairing, with security level comparable to 1024-bit RSA, can be done on a MICAz sensor node in just 5.3 seconds, using only 154 bytes of RAM and 8,576 bytes of ROM. To the best of our knowledge, this is the most efficient nesC implementation to date. Also, when compared with the best known result found in the literature, our implementation reduces the RAM usage by 75 % and the ROM usage by 51%. The resulting size of our implementation corresponds to only 3.7 % and 6.5 % of the RAM and ROM capacities of MICAz, respectively

TinyPairing: A Fast and Lightweight Pairing-Based Cryptographic Library for Wireless Sensor Networks

Abstract—Computing Bilinear Pairing on sensor platforms has become an important research topic since the introduction of pairing-based cryptography to Wireless Sensor Networks (WSNs). Some previous works have provided benchmarks for the pairing computation on sensors. However, a complete pairing-based cryptographic scheme requires much more than just a bilinear pairing operation, and little work has been done yet in this area. In this paper, we present the first fully functional pairing-based cryptographic library for WSNs. The library is fast and lightweight, and has an additional of one identity-based encryption scheme and two short signature schemes included. We also propose several new algorithms and techniques, and show that they significantly improve the speed and reduce the memory usage of the library. The performance results of implementing the three pairing-based cryptographic schemes show that pairing-based cryptosystems are feasible and applicable in WSNs. In particular, the amount of RAM and ROM taken by each of these pairing-based cryptographic schemes is no more than 10% and 20%, respectively, of the total capacities of a MICAz mote. Index Terms—pairing-based cryptosystems; cryptographic li-brary for motes; secure wireless sensor networks; and security and privacy I

Exhaust noise, performance and emission characteristics of spark ignition engine fuelled with pure gasoline and hydrous ethanol gasoline blends

The exhaust noise, performance and emission characteristics of a gasoline engine fuelled by hydrous ethanol gasoline with 10%, 20% hydrous ethanol by volume (E10W and E20W) and pure gasoline (E0) were experimentally investigated. The tests were performed at full load and different engine speeds varying from 1500 rpm to 5000 rpm. The results showed that compared with E0, E10W and E20W had much lower exhaust noise at low engine speeds. With the increase of engine speed, E0 showed an advantage in low exhaust noise. However, engine fuelled with three fuels displayed comparable noise emissions at high speed. In addition, better thermal efficiency, significantly decreased CO and HC emissions were achieved by hydrous ethanol gasoline at all tested operating conditions. However, significant NOx emission and slight BSFC were observed for E10W and E20W. Compared with E20W, E10W showed decreased BSFC, HC and NOx emissions with the increase of engine speed, while CO emission was only slightly increased. Hydrous ethanol gasoline was capable of realizing comparable torque and power with E0 at all operating conditions. From the results above, hydrous ethanol gasoline could be considered as a promising alternative for SI engine. What's more, E10W exhibits enhanced performance. Keywords: Exhaust noise, Performance characteristics, Emission characteristics, Hydrous ethanol content, Spark ignition engin

A new elasmothere genus and species from the middle Miocene of Tongxin, Ningxia, China, and its phylogenetic relationship

The elasmotheres were well diversified and widespread throughout the Neogene in Eurasia and East Africa. Here we report a new elasmothere genus and species, Tongxinotherium latirhinum gen. et sp. nov., from the Zhang’enbao Formation (middle Miocene) of Tongxin, Ningxia, China. The new genus is characterized by a broad and thick nasal bone, the ‘U’-shaped nasal notch located at the level of P3, the anterior margin of the orbit situated at the level of M2, subhypsodont teeth covered and filled by plentiful cement, slightly developed enamel foldings, expanded protocone with anterior and posterior constrictions, the middle valley and posterior valley closed on the premolars, protoloph separated from the ectoloph on P2, and buccal and lingual cingula present on premolars, but absent on molars. A phylogenetic analysis reveals that Tongxinotherium latirhinum gen. et sp. nov. is more derived than the early elasmotheres, and more primitive than Iranotherium and Ningxiatherium, bridging a morphological and stratigraphical gap between them. The discovery of new material improves the morphological characteristics of the early elasmotheres’ horns and increases the diversity of the middle Miocene elasmotheres. http://zoobank.org/urn:lsid:zoobank.org:pub:7DF2F57F-38DD-4FBF-B3DF-57AADD510131</p

Contrasting Pre-Mei-Yu and Mei-Yu Extreme Precipitation in the Yangtze River Valley: Influencing Systems and Precipitation Mechanisms

The mei-yu season over the Yangtze-Huai Rivers basin, typically occurring from mid-June to mid-July, is one of three heavy-rainfall periods over China and can contribute 50% of the annual precipitation. In this study, the first and second heaviest daily precipitation events at the Wuhan station have been selected to represent typical mei-yu and pre-mei-yu precipitation events where the differences in the atmospheric thermodynamic characteristics, precipitation nature, influencing systems, and mechanisms are investigated. During the mei-yu case, moist air mainly came from the South China Sea. Precipitation occurred south of the mei-yu front where abundant moisture and favorable thermodynamic conditions were present. The main influencing systems include a stable blocking pattern and strong and stable western Pacific subtropical high in the midtroposphere, and a small yet intense mesoscale cyclonic vortex in the low troposphere. Rainfall in Wuhan was continuous, caused by a well-organized convective line. A heavy rainband was located along the narrow band between the elongated upper-level jet (ULJ) and the low-level jet (LLJ) where the symmetric instability was found in the midtroposphere near Wuhan. Quite differently, for the pre-mei-yu precipitation case, moist air primarily came from the Beibu Gulf and the Bay of Bengal. Precipitation happened in the low-level convective instability region, where a short-wave trough in the midtroposphere and a mesoscale cyclonic vortex in the low-troposphere were found. Precipitation in Wuhan showed multiple peaks associated with independent meso-beta-scale convective systems. A rainstorm occurred at the exit of the LLJ and the right entrance of the ULJ, where convective instability exited in the mid- to low troposphere.National Natural Science Foundation of ChinaNational Natural Science Foundation of China [41705019, 41620104009, 91637211]; IHR; U.S. National Science FoundationNational Science Foundation (NSF) [AGS-1354402, AGS-1445956]6 month embargo; published online: 16 November 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Development and Characterization of a Novel Porous-Media Borosilicate Glass Ion Sources for Electrospray Thruster

The porous-media-based electrospray thruster is a cutting-edge micropropulsion technology that can revolutionize the capabilities of microsatellites. This paper reports the design, fabrication, and characterization of a novel porous-media borosilicate glass electrospray thruster. The porous glass used here is integrally formed by the phase separation method, which make it display outstanding pore uniformity and processability. The picosecond ultraviolet laser processing technique is applied to machine 361 emitters out of glass. Performance characteristic experiments are conducted with the thruster passively fed with ionic EMI-BF4 liquid. The results reveal that the per-emitter can emit up to 200.46 nA of ion current at 2 kV. The novel porous glass and the corresponding machine method present an opportunity to attain more-controllable emitter shapes, which has a positive impact on thruster lifetime and performance improvement