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In vivo positron emission tomography (PET) using [C11]-labeled Pittsburgh Compound B ([C11]PiB) has previously been shown to detect amyloid-β (Aβ) in late-onset Alzheimer disease (LOAD) brain; however, the sensitivity of this technique for detecting β-amyloidosis in autosomal dominant Alzheimer disease (ADAD) has not been systematically investigated. To validate [C11]PiB PET as a useful biomarker of β-amyloidosis, we measured the cortical and regional standardized uptake value ratios (SUVRs) in 16 ADAD and 15 LOAD cases and compared them with histopathologic measures of β-amyloidosis in postmortem brain. The PiB-PET data were obtained between 40–70 min after bolus injection of ∼15 mCi of [11C]PiB. MRI and PiB-PET images were co-registered and SUVRs were generated for several brain regions. Using Aβ immunohistochemistry (10D5, Eli Lilly), the burden of Aβ plaques was quantified in 16 regions of interest using an area fraction fractionator probe (Stereo Investigator, MicroBrightfield, VT). There were regional variations in Aβ plaque burden with highest densities observed in the neocortical areas and the striatum. On spearman correlations, in vivo PiB-PET correlated with postmortem Aβ plaque burden in both LOAD and ADAD, with strongest correlations seen in neocortical areas. In summary, [C11]PiB-PET has utility as a biomarker in both ADAD and LOAD.
This presentation will enable the learner to:
1.Discuss how PET-PiB beta-amyloid imaging is used as a potential biomarker of Alzheimer disease (AD)
2.Correlate postmortem neuropathologic evidence of beta-amyloidosis with PET-PiB data, and learn that PET-PiB is a potentially useful tool to detect beta-amyloidosis in presymptomatic and symptomatic individuals
This paper reports scanning microwave microscopy of CMOS interconnect aluminum lines both bare and buried under oxide. In both cases, a spatial resolution of 190 ± 70 nm was achieved, which was comparable or better than what had been reported in the literature. With the lines immersed in water to simulate high-k dielectric, the signal-to-noise ratio degraded significantly, but the image remained as sharp as before, especially after averaging across a few adjacent scans. These results imply that scanning microwave microscopy can be a promising technique for non-destructive nano-characterization of both CMOS interconnects buried under oxide and live biological samples immersed in water.
Although previous studies have investigated the association of cruciferous vegetable consumption with breast cancer risk, few studies focused on the association between bioactive components in cruciferous vegetables, glucosinolates (GSL) and isothiocyanates (ITC), and breast cancer risk. This study aimed to examine the association between consumption of cruciferous vegetables and breast cancer risk according to GSL and ITC contents in a Chinese population. A total of 1485 cases and 1506 controls were recruited into this case–control study from June 2007 to March 2017. Consumption of cruciferous vegetables was assessed using a validated FFQ. Dietary GSL and ITC were computed by using two food composition databases linking GSL and ITC contents in cruciferous vegetables with responses to the FFQ. The OR and 95 % CI were assessed by unconditional logistic regression after adjusting for the potential confounders. Significant inverse associations were found between consumption of cruciferous vegetables, GSL and ITC and breast cancer risk. The adjusted OR comparing the highest with the lowest quartile were 0·51 (95 % CI 0·41, 0·63) for cruciferous vegetables, 0·54 (95 % CI 0·44, 0·67) for GSL and 0·62 (95 % CI 0·50, 0·76) for ITC, respectively. These inverse associations were also observed in both premenopausal and postmenopausal women. Subgroup analysis by hormone receptor status found inverse associations between cruciferous vegetables, GSL and ITC and both hormone-receptor-positive or hormone-receptor-negative breast cancer. This study indicated that consumption of cruciferous vegetables, GSL and ITC was inversely associated with breast cancer risk among Chinese women.
Based on large-signal theory, a one-dimensional theoretical model of a coaxial vircator is developed to give the microwave gain of the nonlinear beam–wave interaction, and the effect of injected current premodulation on the microwave gain is analysed theoretically. In addition, a coaxial vircator with improved dual-cavity modulation structure, which has the advantage of enhancing the effect of the modulation cavity on the injected electron beam by way of feedback microwaves, is presented. The simulation results are presented to test the validity of the proposed theory, and it can be seen that the system power efficiency can become further strengthened by adjusting the parameters of the microwave feedback channel until the feedback electric field is at the proper phase. Finally, through optimization, a structure capable of generating 7.05 GW average output power and 19.5 % power conversion efficiency at 2.95 GHz operating frequency is obtained.
To conduct a meta-analysis to compare the short-term outcomes of robotic thyroidectomy and conventional open thyroidectomy for differentiated thyroid cancer.
Medline, Embase, Science Citation Index Expanded and the Cochrane Library databases were searched for relevant literature. The evaluated endpoints were intra-operative and post-operative outcomes.
Twelve eligible, non-randomised comparative studies involving 2513 patients were included, with 923 patients in the robotic thyroidectomy group and 1590 patients in the conventional open thyroidectomy group. Meta-analysis results revealed that robotic thyroidectomy was associated with significantly longer operative time and a lower number of retrieved central lymph nodes, as compared with conventional open thyroidectomy. No significant differences were found between robotic thyroidectomy and conventional open thyroidectomy in terms of post-operative outcomes.
Robotic thyroidectomy appears to be a feasible and safe surgical procedure for patients with differentiated thyroid cancer. However, more high-quality randomised clinical trials should be undertaken to confirm these findings.
We report the Eu doping induced improvement on the second harmonic generation (SHG) of ZnO nanowires and correlates with the structural modification and corresponding linear absorption. A non-monotonic enhancement in the SHG emission is observed with the increase of Eu concentration. To understand the underlying mechanism, the effective second order non–linear coefficient (deff) is calculated from the theoretical fitting with considering the absorption effect. The highest deff (19.09±0.11 pm/V) is obtained for the 1 at.% Eu doped ZnO nanowires, which is several times larger than the standard SHG material β-BaB2O4 (BBO). Dependence of the deff with the Eu doping, structural modification and absorption magnitude are systematically discussed.
Recently, Fickenscher et al.  have shown that, in a core-multi-shell structure where a GaAs quantum well is embedded into an AlGaAs shell wrapped around a  oriented GaAs nanowire, the electron and hole ground states are strongly confined to the corners of the hexagonally symmetric quantum well. Thus this confinement defines quantum wires which run along the length of the nanowires along its corners. Here we review single nanowire photoluminescence measurements which show the significant confinement energy of the excitons. For well widths larger than 5 nm, optical transitions between electron and hole excited states can be seen in excitation spectra, while for widths less than 5 nm only the ground state optical transitions are observed. For well widths smaller than 5 nm, high resolution spatially resolved photoluminescence measurements show directly the appearance of localized states. Single nanowire spectra from the 4 nm QWT sample display ultranarrow emission lines on the high energy side of the luminescence band. Spatially-resolved PL images show that these quantum dots are localized randomly along the length of the wire.
We use Raman scattering to study the spatially-resolved strain and stress in a complex zinc blende GaAs/GaP heterostructured nanowire which contains both axial and radial interfaces. The nanowires are grown by metal-organic chemical vapor deposition in the  direction with Au nano particles as catalysts, High spatial resolution Raman scans along the nanowires show the GaAs/GaP interface is clearly identifiable. We interpret the phonon energy shifts in each material as one approaches the interface.
Carbon nanotube ﬁeld effect transistors (CNT FETs) have many possible applications in future nano-electronics due to their excellent electrical properties. However, one of the major challenges regarding their performance is the noticeable gate hysteresis which is often displayed in their transfer characteristics. The hysteresis phenomenon is often attributed to water-mediated charge transfer between the CNT and the dielectric layer or the CNT and the water layer itself. In this study, we implement three different experimental techniques and provide evidence that the hysteresis phenomenon of suspended CNT FETs, as well as of on-surface CNT FETs which operate at low gate voltage regimes (| Vg | < 3V), is based on gate-induced, water-assisted redistribution of mobile charge on the SiO2 surface, and it is not related to charge injection from the CNT itself. Two techniques are based on the current measurements through the CNT and the third utilizes electrostatic force microscopy (EFM) setup. In addition, the applied external gate voltage affect the relaxation time of the current. This change arises from the modification of the amount of water layers which adsorb onto the dielectric surface, which caused by dielectrophoresis attraction between the water molecules and the substrate. It is found that the relaxation time, and hence the surface conductivity, are very sensitive for the first few layers, and saturates above three monolayers of water molecules.
We analyze and compare optoelectronic properties and hot carrier relaxation dynamics in different forms of TiO2 anatase materials: nanowires and thin films. The models are chosen in such way that the same crystallographic surfaces are exposed and any difference in properties is attributed to the change of the dimensionality of the nanostructure. Specifically, we give a brief review of the electronic properties and non-adiabatic excited state dynamics of <001> anatase TiO2 nanowire as well as (100) and (001) anatase TiO2 surfaces. The calculated band gap of nanowire is larger than the ones of surfaces. The hole relaxation rate is higher than the electron relaxation rate for both the surfaces and nanowire, and the electron and hole relaxation rates of surfaces are larger than the ones of nanowire.
High yield nanomanufacturing is important to turning nanotechnology advances into industrial products. Electrospinning is a nanomanufacturing process that has been used to process advanced ceramic nanofibers suitable for functional applications in sensing and catalysis, yet it has been limited in its scalability thus far. In this study a novel design of the electrospinning process and related equipment that could produce large qualities of ceramic nanofibers is described. This scaled-up approach to traditional needle electrospinning allows the formation of 24 jets operating under the same conditions as those set in the single jet lab-based process. Due to a thin metallic disc design, with tiny (0.5mm) holes drilled at the bottom corner of the disc, all jets experience a uniform impact of the electrostatic field. Continuous replenishment of the source disk at higher flow rates allows for high yields of nanofibers.
In recent years, studies have shown that single crystal metallic nanowires (NWs) can exhibit unique pseudoelastic behavior when their cross-sectional area is smaller than a certain critical value, which is on the order of a few nms. The mechanism responsible for this behavior is the formation of partial dislocations (twinning). In this paper we demonstrate using molecular dynamics simulations that thicker composite nanowires can exhibit pseudoelastic behavior at large cross-sectional dimensions to 28 nm and higher, as long as the individual layer thickness do not exceed a critical value of 1.8-2 nm, thus making their manufacturing feasible and more attractive.
This study aims at investigating the formation of nanofibers containing poly (vinylidene fluoride) (PVDF) and Fe3O4 nanoparticles using magnetic field assisted electrospinning. For this purpose, two Helmholtz coils were mounted on the electrospinning apparatus in order to create a uniform magnetic field. Different separations, angles and magnetic fields are being analyzed. Polymeric solutions containing PVDF, DMF and acetone with a concentration of 18 wt% were adopted (DMF to Acetone ratio of 3 to 1). Iron Oxide Nanopowder (Fe3O4, particle diameter of 20 nm to 30 nm) to PVDF ratios are 1:5, 1:10 and 1:15. The application of the electromagnetic field during fiber deposition results in better orientation of the polymer flow towards the grounded electrode and leads to smoother fibers with diameters in the range of hundreds of nanometers. Blisters, probably related to Fe3O4 agglomerates, were distributed on the surface of all samples of this study. A magnetic field response of the nanofibers with higher magnetic fields was clear observed. By adding more Fe3O4 to the polymeric solution the ferromagnetic response on thin films and nanofibers was improved. The analysis of circular capacitors revealed a full dielectric response.