To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Decreased hemoglobin levels increase the risk of developing dementia among the elderly. However, the underlying mechanisms that link decreased hemoglobin levels to incident dementia still remain unclear, possibly due to the fact that few studies have reported on the relationship between low hemoglobin levels and neuroimaging markers. We, therefore, investigated the relationships between decreased hemoglobin levels, cerebral small-vessel disease (CSVD), and cortical atrophy in cognitively healthy women and men.
Cognitively normal women (n = 1,022) and men (n = 1,018) who underwent medical check-ups and magnetic resonance imaging (MRI) were enrolled at a health promotion center. We measured hemoglobin levels, white matter hyperintensities (WMH) scales, lacunes, and microbleeds. Cortical thickness was automatically measured using surface based methods. Multivariate regression analyses were performed after controlling for possible confounders.
Decreased hemoglobin levels were not associated with the presence of WMH, lacunes, or microbleeds in women and men. Among women, decreased hemoglobin levels were associated with decreased cortical thickness in the frontal (Estimates, 95% confidence interval, −0.007, (−0.013, −0.001)), temporal (−0.010, (−0.018, −0.002)), parietal (−0.009, (−0.015, −0.003)), and occipital regions (−0.011, (−0.019, −0.003)). Among men, however, no associations were observed between hemoglobin levels and cortical thickness.
Our findings suggested that decreased hemoglobin levels affected cortical atrophy, but not increased CSVD, among women, although the association is modest. Given the paucity of modifiable risk factors for age-related cognitive decline, our results have important public health implications.
We investigated the effect of human induced pluripotent stem cell (hiPS) medium on porcine somatic cell nuclear transfer and bovine in vitro fertilized early blastocysts, in comparison with North Carolina State University (NCSU)-37 medium and in vitro culture (IVC)-II medium. After 2 days of culture, the diameter of the portion of the blastocyst that was extruded from the zona pellucid dramatically differed between porcine blastocysts cultured in hiPS medium and those cultured in NCSU-37 medium (221.47 ± 38.94 μm versus 481.87 ± 40.61 μm, P < 0.01). Moreover, the diameter of the portion of the blastocyst significantly differed between bovine blastocysts cultured in hiPS medium and those cultured in IVC-II medium (150.30 ± 29.49 μm versus 195.58 ± 41.59 μm, P < 0.01). Furthermore, the total number of cells per porcine and bovine blastocyst was more than two-fold higher in blastocysts cultured in hiPS medium than in those cultured in NCSU-37 medium (44.33 ± 5.28 and 143.33 ± 16.05, P < 0.01) or IVC-II medium (172.12 ± 45.08 and 604.83 ± 242.64, P < 0.01), respectively. These results indicate that hiPS medium markedly improves the quality of porcine and bovine blastocysts.
An indexed offset distance of the tricuspid septal leaflet ⩾8 mm/m2 is a quantitative criterion for the diagnosis of Ebstein’s anomaly. The purpose of this study was to investigate the validity of this criterion for the discrimination of Ebstein’s anomaly from pulmonary atresia with intact ventricular septum in neonatal patients. A total of 122 neonatal patients, 56 with Ebstein’s anomaly and 66 with pulmonary atresia with intact ventricular septum, were enrolled. Diagnosis of each anomaly was based on typical morphologic features. Echocardiographic variables, including the offset distance of the tricuspid septal leaflet, were measured via an offline analysis of images recorded before 1 month of age. The offset distance of the tricuspid septal leaflet was indexed by the body surface area, and the indexed offset distances in the Ebstein’s anomaly and pulmonary atresia with intact ventricular septum groups were 34.2 mm/m2 (7.1–119.1 mm/m2) and 7.2 mm/m2 (0.0–25.6 mm/m2), respectively. The indexed offset distance was ⩾8 mm/m2 in 29 (43.9%) of the patients with pulmonary atresia with intact ventricular septum; clinical and echocardiographic characteristics were comparable between these 29 patients and the remaining 37 patients with pulmonary atresia with intact ventricular septum. When an indexed offset distance ⩾8 mm/m2 was applied as a cut-off for the diagnosis of Ebstein’s anomaly, the sensitivity was 0.963 and the specificity was 0.561. In conclusion, indexed offset distance ⩾8 mm/m2 cannot be used as a cut-off for the diagnosis of complicated Ebstein’s anomaly in neonatal patients with pulmonary atresia with intact ventricular septum.
Human complement regulatory protein hCD46 may reduce the hyperacute rejection (HAR) in pig-to-human xenotransplantation. In this study, an hCD46 gene was introduced into porcine embryonic germ (EG) cells. Treatment of human serum did not affect the survival of hCD46-transgenic EG cells, whereas the treatment significantly reduced the survival of non-transgenic EG cells (p < 0.01). The transgenic EG cells presumably capable of alleviating HAR were transferred into enucleated oocytes. Among 235 reconstituted oocytes, 35 (14.9%) developed to the blastocyst stage. Analysis of individual embryos indicated that 80.0% (28/35) of embryos contained the transgene hCD46. The result of the present study demonstrates resistance of hCD46-transgenic EG cells against HAR, and the usefulness of the transgenic approach may be predicted by this cytolytic assessment prior to actual production of transgenic pigs. Subsequently performed EG cell nuclear transfer gave rise to hCD46-transgenic embryos. Further study on the transfer of these embryos to recipients may produce hCD46-transgenic pigs.
To improve the IPD reliability of NAND flash memory, plasma oxidation was introduced as the post-treatment process of ONO (Oxide/Nitride/Oxide) IPD. The LP-CVD SiO2 modified by plasma oxidation showed the excellent electrical properties. e.g., low leakage current, high breakdown voltage etc. By the analysis of Tof-SIMS and XRR, we could observe the several changes of physical characteristics such as the reduction of impurities (H, N etc.), the increase of oxide density, and the improvement of oxide surface roughness. We found out the appropriate treatment condition to be able to densify oxide layer without the addition of ONO Equivalent Oxide Thickness (EOT). The LP-CVD SiO2 prepared by plasma oxidation was used for the ONO IPD of 50nm NAND flash device and also compared with the conventional LP-CVD SiO2 in the aspect of the IPD reliability.
The hydrophobicity of poly Si is reported to introduce different polishing behavior with careful control of post CMP cleaning process. The purpose of this study was to investigate the effect of poly Si wettability on its CMP behavior. The adhesion force of polymeric particle on the poly Si wafer surfaces was measured in the KOH solution (pH 11) as a function of solution A concentration. Adhesion force decreased and saturated as a function of concentration of solution A. The change of surface wettability affects not only the polishing rates but also the level of contamination on wafer because the interactions between particles and substrates are dependent on the wettability of the surface. Also, hydrophobic poly Si surfaces attracted much more pad particles with water marks than hydrophilic
The swelling behavior of chitosan hydrogels in ionic liquid–water binary systems was studied using hydrophilic room-temperature ionic liquids (RTILs) to elucidate the swelling properties of chitosan hydrogels. It was confirmed that chitosan hydrogels are much stiffer after immersing in a pure RTIL because the water existing inside the chitosan polymer network is extracted into the RTIL. The pH of the binary system changes when the RTIL is in contact with water. The chitosan hydrogels were fully dissociated at a 90% water content in the BMI-BF4-water binary system. The equilibrium binary system content behavior of the chitosan hydrogels depended upon the amount of free water present. The water behavior in a pure RTIL was examined using differential scanning calorimetry.
Composite fibers composed of chitosan and single-wall carbon nanotubes (CNTs) have been fabricated using a wet spinning method. The dispersion was improved by the sonic agitation of the CNTs in a chitosan solution followed by centrifugation to remove tube aggregates and any residual catalyst. The mechanical behavior was investigated using a dynamic mechanical analyzer (DMA). The mechanical tests showed a dramatic increase in Young's modulus for the chitosan/CNT composite fibers fabricated using the improved dispersion method. The strain on the microfibers was determined from tensile load measurements during pH switching in acidic or basic electrolyte solutions. The microfibers showed a general actuation behavior of expanding at pH = 2 and contracting at pH = 7 under low tensile loads. However, a reverse of this actuation behavior was exhibited under high tensile loads. This anomalous pH actuation is both new and surprising. It was explained from an analysis of the differences in sample stiffness and Poisson’s ratio under tensile load in electrolyte solutions with different pH values.
Composite nanofibers including ferritin nanoparticles or multiwalled carbon nanotubes (MWCNTs) were fabricated to enhance the physical properties of the nanofibers, such as the elastic modulus and electrical conductivity. The ferritin was homogeneously incorporated in the polymeric nanofibers, but excess carbon nanotubes (CNTs) added to the polymer solution resulted in the fabrication of composite nanofibers with rough surfaces. PVA/ferritin/CNT composite nanofibers were fabricated that had smooth surfaces, and had a good dispersion of ferritin and CNTs. These composite nanofibers are applicable to artificial muscles requiring enhanced physical properties.
The effects of ternary element addition of manganese on microstructure and mechanical properties of nanocrystalline L12 (Al+X at.%Mn)3Ti (X=0 - 12) fabricated by mechanical alloying and spark plasma sintering (SPS) were investigated. The SPS method was used to consolidate nanocrystalline L12 (Al+X at.%Mn)3Ti with the pressure of 50 MPa. The heating rate was 100°C /min. The final sintering temperature was determined from the observation of the shrinkage of the specimen. In binary Al3Ti, the final sintering temperature was 864°C. The sintering temperature was reduced down to 658°C with increasing Mn concentration. After SPS, the L12 structure was maintained in the specimens which contained Mn concentration of 8- 12 at.%. The microhardness test, grain size measurements, and fracture toughness test were conducted as a function of Mn concentration. In order to investigate the effect of the grain size on the microhardness and fracture toughness of the (Al+8 at.%Mn)3Ti, heat treatments were performed in a vacuum furnace ( 10-3 torr ). With increasing heat treatment temperature, the microhardness decreased due to the formation and growth of Al4C3, Al2O3, and TiC, while fracture toughness increased. The fracture toughness of 4.12 MPa m1/2 was attained for the (Al+8 at.%Mn)3Ti specimen and it was the highest value among the specimens after 1h heat treatment at 1100°C. The grain sizes were about 60 nm and 100 nm after 1 h heat treatment at 900°C and 1100°C, respectively.
The high porosity and uniform pore size of mesoporous oxide films offer unique opportunities for microelectromechanical system (MEMS) devices that require low density and low thermal conductivity. This paper provides the first report in which mesoporous films were adapted for MEMS applications. Mesoporous SiO2 and Al2O3 films were prepared by spin coating using block copolymers as the structure-directing agents. The resulting films were over 50% porous with uniform pores of 8-nm average diameter and an extremely smooth surface. The photopatterning and etching characteristics of the mesoporous films were investigated and processing protocols were established which enabled the films to serve as the sacrificial layer or the structure layer in MEMS devices. The unique mesoporous morphology leads to novel behavior including extremely high etching rates and the ability to etch underlying layers. Surface micromachining methods were used to fabricate three basic MEMS structures, microbridges, cantilevers, and membranes, from the mesoporous oxides.
The high porosity and uniform pore size provided by mesoporous oxide films offer interesting opportunities for MEMS devices that require low density and low thermal conductivity. This paper describes recent efforts at adapting mesoporous films for MEMS fabrication. Mesoporous SiO2 and Al2O3 films were prepared using block copolymers as the structure-directing agents, leading to films which were 70% porous and < 5 nm surface roughness. A number of etchants were investigated and good etch selectivity was observed with both dry and wet systems. Micromachining methods were used to fabricate cantilevers, micro bridges and membranes.
Email your librarian or administrator to recommend adding this to your organisation's collection.