Pathogenic genes associated with Parkinson’s disease:molecular mechanism overview

Parkinson’s disease(PD)is a common neurodegenerative disease in the elderly,accounting for more than 1%of the population aged 65 years.Monogenic inheritance is relatively rare in PD,accounting for approximately 5%to 10%of PD patients,and there is a growing body of evidence suggesting that multiple genetic risk factors play a significant role in the pathogenesis of PD.Several groups have identified and reported a number of genes carrying mutations associated with affected family members.Mutated genes associated with PD are also candidates for idiopathic PD,and these genes may also carry other mutation sites that increase risk.When multiple genetic risk factors are combined,the risk of PD is increased to a greater extent,and to unravel the pathogenic pathways that lead to different forms of PD.This review focuses on the association of PD genes,such as Parkinson Disease 1-24(PARK1-24),glucosylceramidase(GBA),GTP cyclohydrolase 1(GCH1),fibroblast growth factor 20(FGF20),nuclear receptor-related factor 1(NURR1),NUS1 dehydrodolichyl diphosphate synthase subunit(NUS1),diacylglycerol Lipase Beta(DAGLB),transmembrane protein(TMEM),ubiquinol-cytochrome c reductase core protein 1(UQCRC1),glycoprotein non-metastatic melanoma protein B protein(GPNMB),dynactin 1(DCTN1),LDL receptor related protein 10(LRP10),monoamine oxidase(MAO),ataxin 2(ATXN2),microtubule associated protein tau(MAPT),pantothenate kinase 2(PANK2),spastic parapplegia type 11(SPG11),polymer gamma(POLG),TATA-box binding protein associated factor 1(TAF1),dual specificity tyrosine phosphorylation regulated kinase 1A(Dyrk1a),and crystallin alpha A(CRYAA),with the pathogenesis of PD.We introduce what is currently known about the molecular genetics of PD to help explain the molecular mechanisms leading to the neurodegenerative disease.

Aerodynamic simulation of evacuated tube maglev trains with different streamlined designs

Based on the Navier-Stokes （N-S） equations of incompressible viscous fluids and the standard k-ε turbu- lence model with assumptions of steady state and two dimensional conditions, a simulation of the aerodynamic drag on a maglev train in an evacuated tube was made with ANSYS/FLOTRAN software under different vacuum pressures, blockage ratios, and shapes of train head and tail. The pressure flow fields of the evacuated tube maglev train under different vacuum pressures were analyzed, and then compared under the same blockage ratio condition. The results show that the environmental pressure of 1 000 Pa in the tube is the best to achieve the effect of aerodynamic drag reduction, and there are no obvious differences in the aerodynamic drag reduction among different streamline head shapes. Overall, the blunt-shape tail and the blockage ratio of 0.25 are more efficient for drag reduction of the train at the tube pressure of 1 000 Pa.

The approach to calculate the aerodynamic drag of maglev train in the evacuated tube

In order to study the relationships between the aerodynamic drag of maglev and other factors in the evacuated tube, the formula of aerodynamic drag was deduced based on the basic equations of aerodynamics and then the calculated result was confirmed at a low speed on an experimental system developed by Superconductivity and New Energy R＆D Center of South Jiaotong University. With regard to this system a high temperature superconducting magnetic levitation vehicle was motivated by a linear induction motor （LIM） fixed on the permanent magnetic guideway. When the vehicle reached an expected speed, the LIM was stopped. Then the damped speed was recorded and used to calculate the experimental drag. The two results show the approximately same relationship between the aerodynamic drag on the maglev and the other factors such as the pressure in the tube, the velocity of the maglev and the blockage ratio. Thus, the pressure, the velocity, and the blockage ratio are viewed as the three important factors that contribute to the energy loss in the evacuated tube transportation.

The time and space characteristics of magnetomotive force in the cascaded linear induction motor

To choose a reasonable mode of three-phase winding for the improvement of the operating efficiency of cascaded linear induction motor, the time and space characteristics of magnetomotive force were investigated. The ideal model of the cascaded linear induction motor was built, in which the B and C-phase windings are respectively separated from the A-phase winding by a distance of d and e slots pitch and not overlapped. By changing the values of d and e from 1 to 5, we can obtain 20 different modes of three-phase winding with the different combinations of d and e. Then, the air-gap magnetomotive forces of A-, B-, and C-phase windings were calculated by the magnetomotive force theory. According to the transient superposition of magnetomotive forces of A-, B-, and C-phase windings, the theoretical and simulated synthetic fundamental magnetomotive forces under 20 different arrangement modes were obtained. The results show that the synthetic magnetomotive force with d = 2 and e = 4 is close to forward sinusoidal traveling wave and the synthetic magnetomotive force with d = 4 and e = 2 is close to backward sinusoidal traveling wave, and their amplitudes and wave velocities are approximately constant and equal. In both cases, the motor could work normally with ahigh efficiency, but under other 18 arrangement modes （d= 1, e=2; d= 1, e=3; d= 1, e=4;...）, the synthetic magnetomotive force presents obvious pulse vibration and moves with variable velocity, which means that the motor did not work normally and had high energy loss.

Vibration characteristics of a multi-block high-temperature superconducting maglev system

The multi-block high-temperature superconducting （HTS） maglev system has more complicated dynamic characteristics than the single-block HTS maglev system. To study its vibration characteristics, we designed a maglev measurement system. The system responses at the excitation frequencies of 2, 3 and 15 Hz were examined. Results show that the responses under excitation frequencies of 2 and 3 Hz include a 6 Hz component, which means that the maglev system is a critical nonlinear system. Moreover, the 6 Hz component is much stronger than the 2 Hz or 3 Hz components in the response spectra. There is the interaction between excitation and response. Under an excitation frequency of 15 Hz, intensified low-frequency perturbations were observed.

Magnetic levitation performance of high-temperature superconductor over three magnetic hills of permanent magnet guideway with iron shims of different thicknesses

Superconducting magnetic levitation performance, including levitation force and guidance force, is important for the application of high-temperature super- conducting maglev. Both of them are not only affected by different arrays of superconductors and magnets, but also by the thickness of the iron shim between permanent magnets. In order to obtain the best levitation performance, the magnetic field distribution, levitation force, and guidance force of a new type of three magnetic hills of permanent magnet guideway with iron shim of different thicknesses （4, 6, and 8 mm） are discussed in this paper. Simulation analysis and experiment results show that the guideway with iron shim of 8 mm thickness possesses the strongest magnetic field and levitation performance when the suspension gap is larger than 10 mm. However, with the decreasing of suspension gap, the guideway with iron shim of 4 mm thickness possesses the best levitation performance. The phenomena can be attributed to the density distribution of flux and magnetization of iron shim.

Physiological and Molecular Changes of Detached Wheat Leaves in Responding to Various Treatments

Leaf senescence is induced or accelerated when leaves are detached. However, the senescence process and expression pattern of senescence-associated genes （SAGs） when leaves are detached are not clearly understood. To detect senescence-associated physiological changes and SAG expression, wheat （Triticum aestivum L.） leaves were detached and treated with light, darkness, low temperature （4℃）, jasmonic acid （JA）, abscisic acid （ABA）, and salicylic acid （SA）. The leaf phenotypes, chlorophyll content, delayed fluorescence （DF）, and expression levels of two SAGs, namely, TaSAG3 and TaSAG5, were analyzed. Under these different treatments, the detached leaves turned yellow with different patterns and varying chlorophyll content. DF significantly decreased after the dark, ABA, JA and SA treatments. TaSAG3 and TaSAG5, which are expressed in natural senescent leaves, showed different expression patterns under various treatments. However, both TaSAG3 and TaSAG5 were upregulated after leaf detachment. Our results revealed senescence-associated physiological changes and molecular differences in leaves, which induced leaf senescence during different stress treatments.