BACKGROUND: With the continuous development of materials science, magnesium alloy vascular stent materials have become a hot research. Because of the mechanical properties and biocompatibility of commercial magnesium alloy, it is difficult to meet the requirements of vascular stents. Therefore, effective measures to improve the sten's surface properties and comprehensive performance become the focus of research.OBJECTIVE: To study the histology and surface modification of vascular stents in rapidly solidified Mg-Zn-Y-Nd alloy.Methods: The low-zinc Mg-2Zn-0.2Y alloy with good mechanical properties and corrosion resistance was selected as the basic material, and Nd and Zn elements were added to refine the alloy stents. After the microstructure of the stent was extruded, the surface modification of the stent was completed and the comprehensive properties of the alloy were improved. The new magnesium alloy for the stent was obtained and the stent surface was modified. The metallographic microstructure, scanning electron microscopy and radiological analysis were used to study the microstructure and mechanical properties of the prepared stents. The mechanical properties of the stents were investigated by hardness and tensile tests.RESULTS AND CONCLUSION: (1) Metallographic microstructure results showed that: when Y elements were not added, the second phase of the magnesium alloy was rod-shaped, and there were a few granules embedded in the matrix. After addition of 0.5% Y elements, in the second phase of the magnesium alloy stent, the shafts were significantly reduced in number, and granules were increased in number and evenly distributed in the body. After the addition of 1% Y,the second phase number increased, a large number of dendrites were visible in the grains, and discontinuous rods existed in the second phase. After the addition of 1.5% Y, the second phase was rod-shaped, with mixture of large and local dendrites in the alloy. (2) X-ray diffraction test results: Mn-Zn-0.5Nd alloy and Mn-Zn-1.0Nd alloy contained the same phases (Mg4Zn7 and (Nd, Y) 2Zn17 phase). When the concentration of Nd increased to 1%, the new MgZn2 phase appeared in the alloy. (3) SEM & EDS test results of modified magnesium alloy showed that after magnesium alloy modification, the second phase contained Zn, Nd and Y elements, and their contents were very close. EDS analysis showed that after the addition of Zr elements, the level of Zn elements in the lamellar second phase decreased significantly, and the level of Nd and Y elements increased, indicating a more stable performance. (4) Micro-hardness test results showed that with the increasing of the content of magnesium alloy, the alloy microhardness increased. (5)Tensile test results showed that the tensile strength and yield strength of the Mg-Zn-Y-0.5Nd-Zr stent were significantly higher than those of Mg-Zn-Y-0.5Nd, Mg-Zn-Y-1.0Nd,Mg-Zn-Y-1.0Nd-Zr stents (P < 0.05); and the elongation at break of Mg-Zn-Y-0.5Nd-Zr and Mg-Zn-Y-1.0Nd-Zr stents was significantly higher than that of Mg-Zn-Y-1.0Nd and Mg-Zn-Y-0.5Nd stents (P < 0.05). To conclude, with Mg-2Zn-0.2Y as core materials, the material modification could be completed by the addition of Nd and Zn elements, and the surface modification could be implemented by extruding and refining the stent microstructure. The modified material has excellent properties.

Objective To screen the differentially expressed genes in optic tecta of pigeon with monooccular deprivation. Methods Using suppression subtractive hybridization technique,the differentially expressed cDNA library for the left optic tecta of pigeons was constructed;recombinant clones were sequenced randomly and further proved to be the true positive by reverse Northern blot analysis. Results 150 of EST (expressed sequence tags) were sequenced and 16 of them proved true positive,which included those homologous to known genes and those having no matches.138 of ESTs were assigned Accession Number by Genbank.Conclusion\ Our data provided to be the useful clues for studying the development of visual system and the molecular construction of vision center system.

ObjectiveTo study the prevalence rate of post-stroke depression (PSD) of the elderly in the community and analyze risk factors of them. MethodsThe elders of the age of 60 or over were sampled as subjects from a community. Zung (SDS) was used as screening instruments and Hamilton rating scale for depression (HRSD-24) as evaluating scales. The prevalence rate of PSD was surveyed. A structured questionnaire was used and physical examination was carried out. Risk factors measured included baseline information, daily habits, and history of main diseases (hypertension, coronary heart disease, diabetes mellitus, myocardial infarction, and so on). The relationship between risk factors and PSD was analyzed.ResultsThe prevalence of PSD was 9.5%. The risk factors for PSD were life quality and age. ConclusionPost-stroke depression disturbs elder's health and rehabilitation. The prevalence rate and harm of PSD are higher than depression without stroke.

ObjectiveTo investigate the changes of non-linear dynamics characteristic of electroencephalogram (EEG) under three states (eyes closed, mental arithmetic with eyes closed and orientation test with eyes closed), and the application of non-linear dynamic analysis for cognitive function research.MethodsEEG was recorded in 30 healthy young volunteers at three stages. The correlation dimension (D2) and approximate entropy (ApEn) were calculated for all subjects.ResultsD2 and ApEn increased significantly during mental tasks as compared to the rest state with eyes closed (P<0.01). In different mental tasks, the complexity of mental functions and the regions involved in the cognitive task were different.ConclusionNon-linear analysis methods are appropriate for the study of cognitive functions and can help to understand the working mechanism of brain during mental activities.

AIM: To obtain differentially expressed cDNA fragments in the cerebellum of rats and screen unknown expressed sequence tag (EST). METHODS: Suppression subtractive hybridization (SSH) was carried out, in which the cDNA fragments of cerebellum were taken as "tester" and correspondingly that of cerebrum and brain stem as "driver". The homogeneous sequences between the tester and driver were excluded and the rare sequences in cerebellum were enriched by SSH. The differentially expressed cDNA fragments were further cloned for the construction of subtracted cDNA libraries and sequencing. RESULTS: 32 clones were selected and 34 cDNA fragments were sequenced. 8 of 32 were proved to be true positive with reverse Northern assay, 13 of 34 fragments were identified to be new cDNA fragment and given the gene sequence numbers by GenBank (AW288461-AW288474). CONCLUSION: SSH is very useful method for screening differentially expressed genes. Our data may be helpful to understand the molecular mechanism of brain function.

Objective To investigate the expression of apoptosis-related neuclosome assembly protein-1(NAP-1) gene in related brain region of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP) treated mice and beta-amyloid treated rats. Methods The animal models with central nervous system degeneration were established by consecutive administration of MPTP to C57BL mice and injection of beta-amyloid to brain ventricular of SD rats. The RNA in striatum and substantia nigra of mice and the RNA in cortex and hippocampus of rats were extracted. The levels of NAP-1 mRNA in these samples were estimated by RT-PCR. Results For mice, the expression of NAP-1 were decreased after MPTP treatment in substantia nigra, while its expression showed no significant change in striatum. In contrast, no effect on NAP-1 gene expression by beta-amyloid injection can be detected in cortex and hippocampus of rats. Conclusions The apoptosis of dopaminergic neurons in nigrostriatal pathway after MPTP treatment may be related to the expression of NAP-1 gene. But the mechanism of neurodegeneration after beta-amyloid injection in rats may be different.

AIM: To investigated the effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the expression of kinesin superfamily (KIF) genes in striatum and substantia nigra in C57BL mice. METHODS: The Parkinson's disease model was established by consecutive administration of MPTP to C57BL mice. The levels of mRNA for five kinesin superfamily genes, KIF1A, KIF2, KIF3A, KIF4, and KIF5A, in striatum and substantia nigra of mice, were estimated by RT-PCR. RESULTS: In substantia nigra, the expression of KIF genes were decreased after MPTP treatment except KIF2 that showed no significant change. However, the expression of KIF1A, KIF3A and KIF4 were increased in striatum after MPTP treatment, while the expression of KIF2 and KIF5A were similar to that in substantia nigra. CONCLUSION: The lose of dopaminergic neurons in nigrostriatal pathway after MPTP treatment may be related to the expression of KIF genes. [

Pancreatic cancer is a highly malignant tumor with a high mortality.Surgery is the only potential hope of cure for patients with pancreatic cancer.Imaging examination plays an essential role in both the early diagnosis and preoperative assessment.Accurate tumor staging has guiding significance for clinical practice.Appropriate therapeutic schedule will be selected according to the tumor staging,and then patients' prognosis can be evaluated.Recently,the TNM staging systems for pancreatic cancer have been updated by American Joint Committee on Cancer (AJCC).Major changes were made in the T and N staging.This article will review the updates of the 8th edition of AJCC cancer staging for pancreatic cancer from radiography aspect.

Objective To assess the role of the different pancreatic islet β cell function index in the evaluation of glucose metabolism in different duration of type 2 diabetes mellitus (T2DM).Methods Normal glucose tolerance subjects without diabetes family history (NC group,48 cases) and T2DM patients (182 cases) were enrolled.The T2DM patients were divided into three groups:less than 5 years group (DM ＜5 group,74 cases),5-10 years group (DM5-10 group,51 cases) and more than 10 years group ( DM ＞10 group,57 cases).Oral glucose tolerance test (OGTT) and insulin release test were taken in all groups.Insulin resistance index (HOMA-IR) and whole body insulin sensitivity index [ISI(Matsuda)] were used to estimate insulin sensitivity,and early insulin secretion index ( △ I30/ △ G30) and glucose disposition index (DI) were used to evaluate the function of pancreatic islet β cell.Results HOMA-IR was increased and ISI (Matsuda) was decreased in DM ＜5 group,DM5-10 group and DM ＞10 group compared with those in NC group [HOMA-IR:8.78 ± 7.12,8.08 ± 3.67,7.84 ± 5.08 vs.4.76 ± 3.43;ISI(Matsuda):46.78 ± 29.00,36.71 ± 16.67,38.86 ±21.72 vs.61.13 ± 32.08,P ＜ 0.05],however,there was no significant difference among DM ＜5 group,DM5-10 group and DM ＞10 group.△ I30/ △ G30 and DI were decreased in DM ＜5 group,DM5-10 group and DM ＞10 group compared with those in NC group [ △ I30 △ G30:( 68.41 ± 361.52 ),(4.31 ± 3.42 ),(7.70 ± 5.78 ) mU/mmol vs.(92.65 ± 309.29) mU/mmol;DI:0.0421 ± 0.0123,0.0412 ± 0.0123,0.0363 ± 0.0116 vs.0.1151 ± 0.0236,P ＜ 0.05 ],and there was no significant difference in △ I30 / △ G30 among DM ＜5 group,DM5-10 group and DM ＞10 group,however,DI was decreased in DM＞10 group compared with that in DM＜5 group and DM5-10 group (P＜0.05).ConclusionsHOMA-IR,ISI (Matsuda),△I30/△G30 are not sensitive to evaluate the insulin resistance of different duration.DI can reflect the glucose utilization of pancreatic islet β cell earlier and the ability to regulate blood sugar steady state changes.

Objective To find out whether conversation analysis helps to differentiate psychogenic nonepileptic seizure (PNES) from epileptic seizure in Chinese patients.Methods Twelve unselected patients from Peking Union Medical College Hospital during 2014 to 2016 with diagnostic uncertainty were included.Interactions following standard protocol were carried out.A linguist blinded to all medical data and a neurologist studied videos and transcripts of the interactions.Using a diagnostic scoring aid which includes 17 conversation features summarized from previous researches, they attempted to predict the medical diagnosis of those patients independently.Results Accurate diagnosis was predicted in 10/12 patients by both raters.Average scores of patients with epileptic seizures were 8.00 (linguist) and 6.75 (neurologist), while average scores of paitents with PNES were-5.75 (linguist) and-7.88 (neurologist).Both raters agreed on most individual items (81.86%, 167/204).To demonstrate different features between these two groups, a case comparison was made between one patient with frontal lobe epilepsy and one patient with PNES.Conclusion In Chinese patients, conversation analysis can help differentiate between epileptic seizure and PNES.