In this study, metabolic changes in the 79A/C3H, ME7/VM, ME7/C3H, 87V/VM and 22A/SV scrapie mouse models were investigated during the clinical phase of the disease, using in vitro proton nuclear ...magnetic resonance spectroscopy. N‐acetyl‐aspartate was found to be significantly reduced in infected mice of the ME7/C3H (40% reduction), ME7/VM (26%) and 79A/C3H (17%) models when compared to control mice, but not in the 87V/VM and 22A/SV models. The concentration of choline containing compounds and creatine remain unchanged in all models when compared with control murine brains. The level of N‐acetyl‐aspartate reduction correlated with the extent of grey‐matter brain vacuolation. The levels of myo‐inositol were found to be significantly increased in the ME7/VM (143%) and 79A/C3H (132%) models only and no significant changes were observed in the ME7/C3H, 87V/VM and 22A/SV models. These changes did not correspond to the severity of gliosis
The trend toward finer pitch and higher performance integrated circuits (ICs) devices has driven the semiconductor industry to incorporate copper and low-k dielectric materials. However, the low-k ...materials have lower modulus and poorer adhesion compared to the common dielectric materials. Thus, thermo-mechanical failure is one of the major bottlenecks for development of a Cu/low-k larger die flip chip package. Very low modulus underfills must also be avoided because low modulus underfills transfer too much stress to the bumps which result in bump cracking in TC testing. A 2D plane strain analysis was performed to investigate the reliability of Chartered's C 65 nm 21 x 2 lmm 9 metal Cu/ low-k, chips with 150 um interconnect pitch in a FCBGA package. A series of parametric studies are performed by using Polymer Encapsulated Dicing Lane Technology (PEDL) to reduce 1 layer of FSG, variation of Cu post height, die thickness, substrate thickness, and underfill selection. The results obtained from the reduction of the stress in the low-k structure and the inelastic energy in the solder bumps modeling is useful to formulate design guidelines for packaging of large dies.
Twin-twin transfusion syndrome (TTTS) is present in approximately 5-15% of monochorionic-diamniotic twin pregnancies. A chronic blood flow imbalance through placental vascular anastomoses from the ...donor to the recipient twin is considered the pathophysiologic mechanism responsible for the development of TTTS. Discordant echogenicity between the donor and recipient placenta has been proposed in a previous case report as an additional sonographic sign of TTTS. Here, we present a case of TTTS with discordant placental echogenicity characterized by a hyperechoic and thicker placental side in the donor twin associated with reduced vascular Doppler signals, histologic lesions suggestive of ischemic changes, and overexpression of anti-angiogenic factors.
This paper focused on design, assembly and reliability assessments of 21 × 21 mm 2 Cu/Low-K Flip Chip (65 nm technology) with 150 ¿m bump pitch. Metal redistribution layer (RDL) and polymer ...encapsulated dicing lane (PEDL) were applied to the chip wafer to reduce the shear stress on the Cu/low-K layers and also the strain on the solder bumps. The first level interconnects evaluated were Pb-free (97.5Sn2.5Ag), High-Pb (95Pb5Sn) and Cu-post/95Pb5Sn. Two different die thicknesses, such as 750 ¿m and 300 ¿m, were evaluated. the flip chip assembly of high-pb test vehicles required the right choice of flux and special alignment between the high-pb solder bumps and substrate presolder to ensure proper solder bumps and substrate pre-solder alloy wetting. Finite Element Modeling (FEM) was performed to investigate the impact of different underfill, on the inelastic strain of the outermost bumps and shear stress in the Cu/low-K layer. JEDEC standard reliability were performed on the test vehicles with different first level interconnects, die thickness, underfill materials and dicing methods.
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