经双下肢行肺灌注显像86例护理体会

本文通过对86例患者经双下肢行肺灌注显像中的护理，包括了解患者的一般情况，病情及心理护理，静脉注射时的剂量、注射时间、速度及注意事项等方面的护理，提高了诊断符合率，预防了并发症的发生，减少了患者的痛苦，达到了早诊断、早治疗的目的。

Microstructural evolution and hot tensile behavior of Mg−3Zn−0.5Zr alloy subjected to multi-pass friction stir processing

The microstructures and hot tensile behaviors of ZK30 alloys subjected to single-and multi-pass friction stir processing(FSP)were systematically investigated.Following single-pass FSP(S-FSP),coarse grains underwent refinement to 1−2μm,with a distinct basal texture emerging in the stir zone(SZ).Additionally,second-phase particles were fragmented,dispersed,and partially dissolved.Multi-pass FSP(M-FSP)further enhanced the homogeneity of the microstructure,reduced texture intensity differences,and decreased the fraction of second-phase particles by 50%.Both S-FSP and M-FSP SZs demonstrated superplasticity at strain rates below 1×10^(−3)s^(−1)and at temperatures of 250−350℃.The S-FSP SZ exhibited an elongation of 390%at 250℃and 1×10^(−4)s^(−1),while the M-FSP SZ achieved an elongation of 406%at 350℃and 1×10^(−3)s^(−1).The superplastic deformation of SZ was co-dominated by grain boundary sliding(GBS)and the solute-drag mechanism in S-FSP and mainly by GBS in M-FSP.

Preparation,microstructure and degradation behavior of Mg−2Zn−0.4Sc−0.2Zr alloy wire

A biodegradable Mg−2Zn−0.4Sc−0.2Zr(ZK20−0.4Sc)alloy wire with a diameter of 0.5 mm was prepared by a combination of hot extrusion and cold-drawing.The average grain size of ZK20−0.4Sc alloy wire on the longitudinal section along the drawing direction is approximately 7.3μm.The texture results show relatively strong<1020>and weak<1010>fiber texture components parallel to the drawing direction.The ZK20−0.4Sc alloy wire exhibits better mechanical properties with the tensile strength,yield strength and elongate of(329±2)MPa,(287±2)MPa and(14.2±0.5)%,respectively.The better mechanical properties are mainly attributed to the grain refinement strengthening,dislocation strengthening and precipitation strengthening.With the immersion time increasing to 14 d,the corrosion type transfers from filament corrosion and pitting corrosion to severe localized corrosion.

Improvement of microstructure and mechanical properties of Al−Cu−Li−Mg−Zn alloys through water-cooling centrifugal casting technique

The microstructure and mechanical properties of as-cast Al−Cu−Li−Mg−Zn alloys fabricated by conventional gravity casting and centrifugal casting techniques combined with rapid solidification were investigated.Experimental results demonstrated that compared with the gravity casting technique,the water-cooling centrifugal casting technique significantly reduces porosity,refinesα(Al)grains and secondary phases,modifies the morphology of secondary phases,and mitigates both macro-and micro-segregation.These improvements arise from the synergistic effects of the vigorous backflow,centrifugal field,vibration and rapid solidification.Porosity and coarse plate-like Al13Fe4/Al7Cu2Fe phase result in the fracture before the gravity-cast alloy reaches the yield point.The centrifugal-cast alloy,however,exhibits an ultra-high yield strength of 292.0 MPa and a moderate elongation of 6.1%.This high yield strength is attributed to solid solution strengthening(SSS)of 225.3 MPa,and grain boundary strengthening(GBS)of 35.7 MPa.Li contributes the most to SSS with a scaling factor of 7.9 MPa·wt.%^(-1).The elongation of the centrifugal-cast alloy can be effectively enhanced by reducing the porosity and segregation behavior,refining the microstructure and changing the morphology of secondary phases.

门控心肌显像在测定左心室射血分数中的应用

目的:应用单光子发射计算机体层摄影(SPECT)技术同时测定不同采集条件下左心室射血分数(LVEF)值,并与超声LVEF值比较,研究其一致性和相关性。方法:选择172例受试者,利用SPECT共行门控显像技术,用99mTc-MIBI作为示踪剂,同时将心动周期设定8和16等份,在一次采集中得到两种条件的LVEF值,并与1周时间所得超声LVEF值作比较,研究门控心肌显像在LVEF测定中的影响因素,以及与常规超声法有无相关性。结果:统计分析显示,心动周期分成8和16等份所得的LVEF值大小是不同的,后者LVEF值较大,但两种方法所得结果存在相关关系。另一方面,SPECT所得的LVEF值均较超声心动图(UCG)所得值大,但与UCG所得结果具有很好一致性。结论:门控心肌显像在心肌活力判断时,利用共行显像技术可同时得到LVEF等心功能参数,其LVEF大小与超声结果有很大相关性,但其值存在显著差异,其正常参考范围尚需进一步研究。

Flow behavior and microstructure of ZK60 magnesium alloy compressed at high strain rate

Flow behavior and microstructure of a homogenized ZK60 magnesium alloy were investigated during compression in the temperature range of 250-400 ℃ and the strain rate range of 0.1-50 s^-1. The results showed that dynamic recrystallization （DRX） developed mainly at grain boundaries at lower strain rate （0.1-1 s^-1）, while in the case of higher strain rate （10-50 s^-1）, DRX occurred extensively both at twins and grain boundaries at all temperature range, especially at temperature lower than 350 ℃, which resulted in a more homogeneous microstructure than that under other deformation conditions. The DRX extent determines the hot workability of the workpiece, therefore, hot deformation at the strain rate of 10-50 s^-1 and in the temperature range of 250-350 ℃ was desirable for ZK60 alloy. Twin induced DRX during high strain rate compression included three steps. Firstly, twins with high dislocation subdivided the initial grain, then dislocation arrays subdivided the twins into subgrains, and after that DRX took place with a further increase of strain.

Effect of Sb content on properties of Sn-Bi solders

The effect of Sb content on the properties of Sn-Bi solders was studied. The nonequilibrium melting behaviors of a series of Sn-Bi-Sb solders were examined by differential scanning calorimetry （DSC）. The spreading test was carried out to characterize the wettability of Sn-Bi-Sb solders on Cu substrate. The mechanical properties of the solders/Cu joints were evaluated. The results show that the ternary alloy solders contain eutectic structure resulting from quasi-peritetic reaction. With the increase of Sb content, the amount of the eutectic structure increases. At a heating rate of 5 ℃/min, Sn-Bi-Sb alloys exhibit a higher melting point and a wider melting range. A small amount of Sb has an impact on the wettability of Sn-Bi solders. The reaction layers form during spreading process. Sb is detected in the reaction layer while Bi is not detected. The total thickness of reaction layer between solder and Cu increases with the increase of the Sb content. The shear strength of the Sn-Bi-Sb solders increases as the Sb content increases.

Evaluation of three kinds of MCrAlY coatings produced by electrospark deposition

Three kinds of MCrAlY coatings with different aluminum contents （5%, 8%, 12%） were prepared by electrospark deposition （ESD）, their microstructure and oxidation behavior were studied by SEM and XRD. The results showed that the phase composition of the coatings changed from single γ-Ni to γ-Ni＋β-NiAl hypoeutectic to γ-Ni＋β-NiAl hypereutectic with increasing aluminum content, and their solidification morphologies changed from cluster of cellular structure to cellular dendrites to coarse dendrites with secondary arms. When exposed at 1000 ℃, the coatings with higher Al content had a stronger tendency to form θ-Al2O3 in the initial several hours. After 100 h of oxidation, a dense and adherent α-Al2O3 scale formed on all of the three coatings but the thickness of α-Al2O3 scale and the amount of remaining θ-Al2O3 increased with increasing Al content. These results revealed different characteristics of ESD MCrAlY coatings which could provide scientific guidance for industrial application.

Microstructure and high temperature tribological behavior of laser cladding Ni60A alloys coatings on 45 steel substrate

The crack-free Ni60 A coating was fabricated on 45 steel substrate by laser cladding and the microstructure including solidification characteristics, phases constitution and phase distribution was systematically investigated. The high temperature friction and wear behavior of the cladding coating and substrate sliding against GCr15 ball under different loads was systematically evaluated. It was found that the coating has homogenous and fine microstructure consisting of γ（Ni） solid solution, a considerable amount of network Ni-Ni3 B eutectics, m^23C6 with the floret-shape structure and Cr B with the dark spot-shape structure uniformly distributing in interdendritic eutectics. The microhardness of the coating is about 2.6 times as much as that of the substrate. The coating produces higher friction values than the substrate under the same load condition, but the friction process on the coating keeps relatively stable. Wear rates of the coating are about 1/6.2 of that of the substrate under the higher load（300 g）. Wear mechanism of the substrate includes adhesion wear, abrasive wear, severe plastic deformation and oxidation wear, while that of the coating is merely a combination of mild abrasive wear and moderate oxidation wear.

Microstructure and biocorrosion behaviors of solution treated and as-extruded Mg-2.2Nd-x Sr-0.3Zr alloys

Mg-2.2Nd-xSr-0.3Zr alloys （x=0, 0.4 and 0.7, mass fraction, %） were prepared by gravity casting. Solution treatment was conducted on the as-cast alloys to homogenize microstructure, and hot extrusion was subsequently conducted. Microstructure was observed using an optical microscope and a scanning electron microscope. Biocorrosion behaviors of the alloy in simulated body fluid were analyzed by mass loss, hydrogen evolution and Tafel polarization experiments. The results show that the amount of residual eutectic phase of the solution treated alloys increases with increasing Sr addition, and the grains are significantly refined after hot extrusion. The corrosion resistance of the solution treated alloys deteriorates apparently with increasing Sr addition, while the corrosion resistance of the as-extruded alloys is improved with Sr addition. Nevertheless, the biocorrosion behavior of the as-extruded alloys obtained by Tafel polarization shows different trends from those obtained by the other two methods.

Fabrication, tribological and corrosion behaviors of detonation gun sprayed Fe-based metallic glass coating

A metallic glass coating with the composition of Fe51.33Cr14.9Mo25.67Y3.4C3.44B1.26 （mole fraction, %） on the Q235 stainless steel was developed by the detonation gun （D-gun） spraying process. The microstructure and the phase aggregate were analyzed by scanning electron microscopy and X-ray diffractometry, respectively. Microhardness, wear resistance and corrosion behavior were assessed using a Vickers microhardness tester, a ball-on-disk wear testing machine and the electrochemical measurement method, respectively. Microstructural studies show that the coatings possess a densely layered structure with the porosity less than 2.1%. The tribological behavior of the coatings examined under dry conditions shows that their relative wear resistance is five times higher than that of the substrate material. Both adhesive wear and abrasive wear contribute to the friction, but the former is the dominant wear mechanism of the metallic glass coatings. The coatings exhibit low passive current density and extremely wide passive region in 3.5% NaCl solution, thus indicating excellent corrosion resistance.

Effects of stabilizing heat treatment on microstructures and creep behavior of Zn-10Al-2Cu-0.02Ti alloy

The microstructures of as-extruded and stabilizing heat-treated Zn-10Al-2Cu-0.02Ti alloys were observed by scanning electron microscopy,transmission electron microscopy,electron probe microanalysis and X-ray diffraction analysis techniques.The change in structure after heat treatment and its effects on room temperature creep behavior were investigated by creep experiments at constant stress and slow strain rate tensile tests.The results show that after stabilizing heat treatment（（350℃,30 min,water-cooling）＋（100℃,12 h,air-cooling））,the amount of α＋η lamellar structure decreases,while the amount of cellular and granular structure increases.The heat-treated Zn-10Al-2Cu-0.02Ti alloy exhibits better creep resistance than the as-extruded alloy,and the rate of steady state creep decreases by 96.9% after stabilizing heat treatment.

Effects of plastic deformation on precipitation behavior and tensile fracture behavior of Mg-Gd-Y-Zr alloy

The effects of plastic deformation on precipitation behavior and tensile fracture behavior of Mg-10Gd-3Y-0.6Zr alloy were investigated.The results indicate that more precipitation cores can be provided by the crystal defects caused by the plastic deformation,as well as increasing the amount of β＇ phases,and the formation of precipitations at grain boundaries and interfaces between the twins and matrix.Because of an increase in precipitations,the dislocation slipping during deformation process is effectively hindered and the matrix is strengthened,especially for the 2% deformed alloy which can achieve a good combination of strength and ductility.With increasing the plastic deformation,the microcracks occur at the interface between grain boundary precipitations and matrix,and then propagate intergranularly.When intergranular fracture combines with the formation of smoothing facets on the fracture surface,the tensile properties decrease.

Effect of zinc addition on microstructure and mechanical properties of Mg-7Y-3Sm-0.5Zr alloy

The effect of zinc addition on the microstructure and mechanical properties of Mg-7Y-3Sm-0.5Zr casting alloy was investigated. Creep test was carried out at 200-300 °C under 50-120 MPa. Within the limits of the creep test conditions used in this study, the creep activation energy of the investigated alloys was in the range of 156-221 kJ/mol. The microstructure evolution during creep was characterized by optical metallography, SEM and TEM. The results show that the creep life of the alloy is increased from 52.2 to 152.8 h at 300 °C under 50 MPa by only 1% addition of Zn, though both the alloys have similar creep behaviors below 250 °C, which suggests that the thermally stable compound and lamellar structure can improve the high temperature creep resistance of the alloy with the addition of Zn.

Clinical phenotype and prevalence of hereditary nonpolyposis colorectal cancer syndrome in Chinese population

AIM: To describe systematically the clinical characteristics and phenotype of HNPCC families and the prevalence of HNPCC in the general population of CRC patients in China. METHODS: HNPCC kindreds and CRC patients were from two sources. One was that we consecutively investigated kindreds and patients by ourselves. And the other was the published Chinese and foreign literature related to Chinese HNPCC syndrome. There were 142 HNPCC families fulfilling AC I and/or AC II including 57 families with detailed data, and 3874 general primary CRC patients in all. All statistical tests were two-sided. RESULTS: In AC I families, the number of Lynch syndrome I and II families were 25 (47.2%) and 28 (52.8%) respectively. There were 215 patients (82.4%) with CRC, 67 patients (25.7%) with extracolonic cancer and 50 patients (19.2%) with multiple primary cancers. In all CRC patients, multiple primary CRC were in 41 patients (19.1%), and the first-CRC was right-sided colorectal cancer in 143 patients (66.5%) and rectal cancer in 44 patients (20.5%). 8.8% and 19.2% of the first cancer were CRC and extracolonic cancers. Among those patients whose first cancer was CRC, 66.8% and 19.9% were right-sided colorectal cancer and rectal cancer, respectively. The similar results were found in AC II families. Normal distribution was only found in the distribution of the age of diagnosis of the first cancer in both AC I families (coefficient of skewness: u = 0.81, 0.20<0.40<P<0.50; coefficient of kurtosis: u = 1.13, 0.20<P<0.40,α=0.20) and AC II families (coefficient of skewness: u=0.63, P>0.5> 0.20; coefficient of kurtosis: u = 0.84, 0.20<0.40<P<0.50, α=0.20), but not found in the distribution of the age of diagnosis of the first CRC. When patients with HNPCC-associated cancer suffered from the first malignant tumor in HNPCC families diagnosed by AC I and AC II, the mean age and median age were 45.1±12.7 years and 44.0 years, 45.2±12.7 years and 44.5 years, respectively. The median age of diagnosis of the first tumor of the patients in the later generation was younger than that in the previous generation. Many extracolonic cancers were found to be associated with HNPCC syndrome. Gastric cancer was the most frequent extracolonic cancer followed by endometrial cancer and hepatocarcinoma. In general population of CRC patients, the prevalence of HNPCC diagnosed by AC I and AC II were 1.3% and 2.2%, respectively. CONCLUSION: The clinical phenotype and prevalence of Chinese HNPCC syndrome are similar to those of Europeans and Americans. Gastric cancer is the most common extracolonic malignant tumor. The age of diagnosis of the first malignant tumor tends to be increasingly younger in patients with HNPCC-related tumors.

Navigation Map Data Representation and Parallel Display Algorithm in an Embedded Environment

Map data display is the basic information representation mode under embedded real-time navigation. After a navigation display data set （NDIS_SET） with several dimensions and corresponding mathematical description formula are designed, a series of rules and algorithms are advanced to optimize embedded navigation data and promote data index and input efficiency. A new parallel display algorithm with navigation data named N PDIS is then presented to adapt to limited embedded resources of computation and memory after a normal navigation data display algorithm named NDIS and related problems are analyzed, N_PDIS can synchronously create two preparative bitmapa by two parallel threads and switch one of them to screen automatically. Compared with NDIS, the results show that N_PDIS is more effective in improving display efficiency.

A review of particulate-reinforced aluminum matrix composites fabricated by selective laser melting

Selective laser melting(SLM)is an emerging layer-wise additive manufacturing technique that can generate complex components with high performance.Particulate-reinforced aluminum matrix composites(PAMCs)are important materials for various applications due to the combined properties of Al matrix and reinforcements.Considering the advantages of SLM technology and PAMCs,the novel SLM PAMCs have been developed and researched in recent years.Therefore,the current research progress about the SLM PAMCs is reviewed.Firstly,special attention is paid to the solidification behavior of SLM PAMCs.Secondly,the important issues about the design and fabrication of high-performance SLM PAMCs,including the selection of reinforcement,the influence of parameters on the processing and microstructure,the defect evolution and phase control,are highlighted and discussed comprehensively.Thirdly,the performance and strengthening mechanism of SLM PAMCs are systematically figured out.Finally,future directions are pointed out on the advancement of high-performance SLM PAMCs.

A large-scale functional approach to uncover human genes and pathways in Drosophila

We demonstrate the feasibility of performing a systematic screen for human gene functions in Drosophila by assaying for their ability to induce overexpression phenotypes. Over 1 500 transgenic fly lines corresponding to 236 human genes have been established. In all, 51 lines are capable of eliciting a phenotype suggesting that the human genes are functional. These heterologous genes are functionally relevant as we have found a similar mutant phenotype caused either by a dominant negative mutant form of the human ribosomal protein L8 gene or by RNAi downregulation of the Drosophila RPL8. Significantly, the Drosophila RPL8 mutant can be rescued by wild-type human RPL8. We also provide genetic evidence that Drosophila RPL8 is a new member of the insulin signaling pathway. In summary, the functions of many human genes appear to be highly conserved, and the ability to identify them in Drosophila represents a powerful genetic tool for large-scale analysis of human transcripts in vivo.

Characterization of hot deformation and microstructure evolution of a new metastableβtitanium alloy

The hot deformation characteristics of as-forged Ti−3.5Al−5Mo−6V−3Cr−2Sn−0.5Fe−0.1B−0.1C alloy within a temperature range from 750 to 910℃and a strain rate range from 0.001 to 1 s^(-1) were investigated by hot compression tests.The stress−strain curves show that the flow stress decreases with the increase of temperature and the decrease of strain rate.The microstructure is sensitive to deformation parameters.The dynamic recrystallization(DRX)grains appear while the temperature reaches 790℃at a constant strain rate of 0.001 s^(-1) and strain rate is not higher than 0.1 s^(-1) at a constant temperature of 910℃.The work-hardening rateθis calculated and it is found that DRX prefers to happen at high temperature and low strain rate.The constitutive equation and processing map were obtained.The average activation energy of the alloy is 242.78 kJ/mol and there are few unstable regions on the processing map,which indicates excellent hot workability.At the strain rate of 0.1 s^(-1),the stress−strain curves show an abnormal shape where there are two stress peaks simultaneously.This can be attributed to the alternation of hardening effect,which results from the continuous dynamic recrystallization(CDRX)and the rotation of DRX grains,and dynamic softening mechanism.

Structure, indentation and corrosion characterizations of high-silicon Ni-Si nano-composite coatings prepared by modified electrodeposition process

Ni-Si nano-composite coatings with various silicon contents were prepared by a modified electrodeposition process using electrolytes containing ball-milled Si/Ni particles. The effects of the concentration of the ball-milled Si/Ni particles in the electrolyte on the silicon content, structure, microhardness and corrosion behaviors of the coatings were investigated. Scanning electron microscopy and X-ray diffractometry were used for structural characterization. Also, the microhardness and corrosion behaviors of the deposited coatings were evaluated. According to the results, the Si level reaches about 10 wt.% in the coating, which is a significant content of Si incorporation for electrodeposition. It was also found that the crystallite size of the coatings was progressively decreased and the hardness was increased, by increasing the content of Si. Typically, the crystallite size and microhardness of the Ni-10 wt.%Si coating were 0.39 and 2.1 times those of the pure Ni coating, respectively. Also, the results showed that there is an optimal content of Si to meet the best acidic corrosion resistance of the coatings.