Shock-induced reaction behaviors of functionally graded reactive material

In this paper,the ballistic impact experiments,including impact test chamber and impact double-spaced plates,were conducted to study the reaction behaviors of a novel functionally graded reactive material(FGRM),which was composed of polytetrafluoroethylene/aluminum(PTFE/Al)and PTFE/Al/bismuth trioxide(Bi_(2)O_(3)).The experiments showed that the impact direction of the FGRM had a significant effect on the reaction.With the same impact velocity,when the first impact material was PTFE/Al/Bi_(2)O_(3),compared with first impact material PTFE/Al,the FGRM induced higher overpressure in the test chamber and larger damaged area of double-spaced plates.The theoretical model,which considered the shock wave generation and propagation,the effect of the shock wave on reaction efficiency,and penetration behaviors,was developed to analyze the reaction behaviors of the FGRM.The model predicted first impact material of the FGRM with a higher shock impedance was conducive to the reaction of reactive materials.The conclusion of this study provides significant information about the design and application of reactive materials.

Update on Molecular Imaging in Parkinson's Disease

Advances in radionuclide tracers have allowed for more accurate imaging that reflects the actions of numerous neurotransmitters, energy metabolism utilization, inflammation, and pathological protein accumulation. All of these achievements in molecular brain imaging have broadened our understanding of brain function in Parkinson’s disease(PD).The implementation of molecular imaging has supported more accurate PD diagnosis as well as assessment of therapeutic outcome and disease progression. Moreover, molecular imaging is well suited for the detection of preclinical or prodromal PD cases. Despite these advances, future frontiers of research in this area will focus on using multi-modalities combining positron emission tomography and magnetic resonance imaging along with causal modeling with complex algorithms.

Cognitive characteristics in Chinese non-demented PD patients based on gender difference

Background:Cognitive impairment is one of the non-motor symptoms in Parkinson’s disease(PD).In the present study,we aim to examine the cognitive function of non-demented Parkinson’s disease patients and compare the results between male and female patients as well as control groups in search of any gender effect.Methods:Sixty PD Patients(30 males and 30 females)from the Movement Disorders Clinic at Huashan Hospital Affiliated to Fudan University were recruited to participate in the study.One hundred age and gender matched control subjects without neurological or psychiatric disorders were voluntarily recruited.The participants were administered measures of cognition in five domains including memory,language,spatial processing abilities,attention and executive function.Results:PD patients attained significantly lower scores in the visual spatial function,language and attention/executive function compared with the control group.Anti-parkinsonian treated patients performed worse in Rey-copy score,Clock Drawing Test(CDT)and Verbal Fluency-City than untreated ones.In regard to gender differences,though no general cognitive differences were found in Mini-mental State Examination(MMSE),men surpassed women on Boston naming test(BNT)while women were superior on Auditory Verbal Learning Test-long(AVLT)delayed cued recall test.Conclusions:Cognitive impairments were common in PD patients even in the absence of dementia.PD patients with anti-parkinsonian medication had worse cognitive impairment than untreated patients.Genders may have different manifestations of cognitive impairment in PD patients.

Morphology evolution and crystallographic feature of Nb nanowire in an in-situ NiTi-Nb nanocomposite

In–situ NiTi shape memory alloy–Nb nanowire nanocomposite was revealed to exhibit exceptional mechanical properties. The properties of high strength and ultra-large elastic strains are closely related with the high performance of in situ-formed Nb nanowire reinforcements. In this study, the morphology evolution and crystallographic feature of Nb nanowires in NiTi shape memory alloy matrix during cold drawing were investigated by means of transmission electron microscopy（TEM）. It is revealed that, as a result of the severe work hardening and amorphization of NiTi matrix, the cold work reduction of nanowire reinforcements can exceed that of the entire composite. The irregular-shaped Nb nanowires are reshaped to straight and smooth nanowires during cold drawing process. By means of TEM nanobeam diffraction,it is revealed that the in situ-formed Nb nanowire in such top-down processed NiTi–Nb composite keeps single crystalline over 1,000 nm at length direction. As a consequence, the aspect ratio of nanowire reinforcements in NiTi matrix exceeds 25：1.

Microstructure of stress-induced martensite in nanocrystalline NiTi shape memory alloy

The microstructure of stress-induced martensite （SIM） in the nanocrystalline NiTi alloy was investigated by means of transmission electron microscopy （TEM）. The result shows that the multi-variant structure of the martensite is suppressed and only single-variant martensitic twins form after tensile deformation when the grain size is smaller than 80 nm. The normal directions of the （001）B19, twin planes are all. within the range of 45° from the axial direction of the wire. The angle between twin crystals （111）M and （111）x of the SIM is also found to be smaller than that of thermally induced martensite in nanocrystalline NiTi.