Role of apparent diffusion coefficient values for the differentiation of viable and necrotic areas of breast cancer and its potential utility to guide voxel positioning for MRS in the absence of dynamic contrast-enhanced MRI data

We carried out retrospective analysis of apparent diffusion coefficient (ADC) values in 48 infiltrating ductal breast cancer patients who had dynamic contrast-enhanced magnetic resonance imaging (DCEMRI; Group I) and in 53 patients (Group II) for whom DCEMRI data were not available. Twenty-three patients of Group I showed no necrosis (Group Ia), while in 25 patients, both viable (nonnecrotic) and necrotic tumor areas (Group Ib) were observed on DCEMRI. T1-weighted, fat-suppressed and short inversion recovery images were used to identify the viable and necrotic tumor areas in Group II patients, and necrosis was not seen in 11 patients (Group IIa), while 42 (Group IIb) showed both viable and necrotic tumor areas. The ADCs of the necrotic area of Group Ib (1.79±0.30 ×10(-3) mm(2)/s) and Group IIb (1.83±0.40 ×10(-3) mm(2)/s) patients were similar and significantly higher (P<.01) compared to the ADCs of the viable tumor area of Group Ia (0.96±0.21 ×10(-3) mm(2)/s) and Group IIa (0.90±0.17 ×10(-3) mm(2)/s) patients. Proton MR spectroscopy (MRS) data were also available in these patients, and the ADC values were retrospectively determined from the voxel from which MR spectrum was obtained. These values were compared with the ADC obtained for the viable and necrotic areas of the tumor. ADC of the MRS voxel was similar to that obtained for the viable tumor area in patients of both groups. This interesting observation reveals the potential utility of using ADC values to identify viable tumor area for positioning of voxel for MRS in the absence of DCEMRI data.     

Vibration suppression of a cantilever beam using magnetically tuned-mass-damper

Eddy currents are induced by the movement of a conductor through a stationary magnetic field or a time varying magnetic field through a stationary conductor. These currents circulate in the conductive material and are dissipated, causing a repulsive force between the magnet and the conductor. These electromagnetic forces can be used to suppress the vibrations of a flexible structure. A tuned mass damper is a device mounted in structures to reduce the amplitude of mechanical vibrations and is one of the effective vibration suppression methods. In the present study, an improved concept of this tuned mass damper for the vibration suppression of structures is introduced. This concept consists of the classical tuned mass damper and an eddy current damping. The important advantages of this magnetically tuned mass damper are that it is relatively simple to apply, it does not require any electronic devices and external power, and it is effective on the vibration suppression. The proposed concept is designed for a cantilever beam and the analytical studies on the eddy current damping and its effects on the vibration suppression. To show the effectiveness of the proposed concept and verify the eddy current damping model, experiments on a cantilever beam are performed. It is found that the proposed concept could significantly increase the damping effect of the tuned mass damper even if not adequately tuned.     

Degradation of orange-G by advanced oxidation processes

The degradation and mineralization of orange-G (OG) in aqueous solutions by means of ultrasound irradiation at a frequency of 213 kHz and its combination with a heterogeneous photocatalyst (TiO₂) were investigated. The effects of various operational parameters such as, the concentration of the dye and solution pH on the degradation efficiency were studied. The degradation of the dye followed first-order like kinetics under the conditions examined. The sonolytic degradation of OG was relatively higher at pH 5.8 than that at pH 12. However, an alkaline pH was favoured for the photocatalytic degradation of OG using TiO₂. Total organic carbon (TOC) measurements were also carried out in order to evaluate the mineralization efficiency of OG using sonolysis, photocatalysis and sonophotocatalysis. The hybrid technique of sonophotocatalytic degradation was compared with the individual techniques of photocatalysis and sonolysis. A simple additive effect was observed during the sonophotocatalytic oxidation of OG using TiO₂ indicating that the combined treatment offers no synergistic enhancement. TOC results also support the additive effect in the dual treatment process.     

Scaling of SiGe Heterojunction Bipolar Transistors

Scaling has been the principal driving force behind the successful technology innovations of the past half-century. This paper investigates the impacts of scaling on SiGe heterojunction bipolar transistors (HBTs), which have recently emerged as a strong contender for RF and mixed-signal applications. The impacts of scaling on key performance metrics such as speed and noise are explored, and both theory and data show that scaling, both vertical and lateral, has mostly beneficial effects on these metrics. However, it is shown that the scaled devices are increasingly vulnerable to device reliability issues due to increased electric field and operation current density. Bipolar transistor scaling rules are reviewed and compared with accumulated reported data for verification. A review of scaling limits suggests that bipolar scaling has not reached the physical fundamental limit yet, promising a continued improvement of bipolar performance in the foreseeable future.     

Concentration bounds for empirical conditional value-at-risk: The unbounded case

Conditional Value-at-Risk (CVaR) is a popular risk measure for modelling losses in the case of a rare but extreme event. We consider the problem of estimating CVaR from i.i.d. samples of an unbounded random variable, which is either sub-Gaussian or sub-exponential. We derive a novel one-sided concentration bound for a natural sample-based CVaR estimator in this setting. Our bound relies on a concentration result for a quantile-based estimator for Value-at-Risk (VaR), which may be of independent interest.     

On the q-analogues of the Zassenhaus formula for disentangling exponential operators

Katriel, Rasetti and Solomon introduced a q-analogue of the Zassenhaus formula written as e_q^(A+B)=e_q^Ae_q^Be_q^c₂e_q^c₃e_q^c₄e_q^c₅… , where A and B are two generally noncommuting operators and e_q^z is the Jackson q-exponential, and derived the expressions for c₂, c₃ and c₄. It is shown that one can also write Explicit expressions for , and are given.     

Relationship between ganglioside expression and anti-cancer effects of the monoclonal antibody against epithelial cell adhesion molecule in colon cancer

The human colorectal carcinoma-associated GA733 antigen epithelial cell adhesion molecule (EpCAM) was initially described as a cell surface protein selectively expressed in some myeloid cancers. Gangliosides are sialic acid-containing glycosphingolipids involved in inflammation and oncogenesis. We have demonstrated that treatment with anti-EpCAM mAb and RAW264.7 cells significant inhibited the cell growth in SW620 cancer cells, but neither anti-EpCAM mAb nor RAW264.7 cells alone induced cytotoxicity. The relationship between ganglioside expression and the anti- cancer effects of anti-EpCAM mAb and RAW264.7 was investigated by high-performance thin-layer chromatography. The results demonstrated that expression of GM1 and GD1a significantly increased in the ability of anti-EpCAM to inhibit cell growth in SW620 cells. Anti-EpCAM mAb treatment increased the expression of anti-apoptotic proteins such as Bcl-2, but the expression of pro-apoptotic proteins Bax, TNF-α, caspase-3, cleaved caspase-3, and cleaved caspase-8 were unaltered. We observed that anti-EpCAM mAb significantly inhibited the growth of colon tumors, as determined by a decrease in tumor volume and weight. The expression of anti-apoptotic protein was inhibited by treatment with anti-EpCAM mAb, whereas the expression of pro-apoptotic proteins was increased. These results suggest that GD1a and GM1 were closely related to anticancer effects of anti-EpCAM mAb. In light of these results, further clinical investigation should be conducted on anti-EpCAM mAb to determine its possible chemopreventive and/or therapeutic efficacy against human colon cancer.     

Interplay between edge states and simple bulk defects in graphene nanoribbons

We study the interplay between the edge states and a single impurity in a zigzag graphene nanoribbon. We use tight-binding exact diagonalization techniques, as well as density functional theory calculations to obtain the eigenvalue spectrum, the eigenfunctions, as well as the dependence of the local density of states (LDOS) on energy and position. We study the strictly zero-energy eigenfunctions using symmetry considerations, as well as tight-binding techniques. Moreover, we note that roughly half of the unperturbed eigenstates in the spectrum of the finite-size ribbon hybridize with the impurity state, and the corresponding eigenvalues are shifted with respect to their unperturbed values. The maximum shift and hybridization occur for a state whose energy is inverse proportional to the impurity potential, and give rise to an impurity peak in the DOS spectrum. We find that the interference between the impurity and the edge gives rise to peculiar modifications of the LDOS of the nanoribbon, in particular to oscillations of the edge LDOS. These effects depend on the size of the system, and decay with the distance between the edge and the impurity.     

Kinetic and Binding Studies Reveal Cooperativity and Off-Cycle Competition for H-Bonding Catalysis with Silsesquioxane Silanols

The catalytic activity, kinetics, and quantification of H-bonding ability of incompletely condensed polyhedral oligomeric silsesquioxane (POSS) silanols are reported. POSS-triols, a homogeneous model for vicinal silica surface sites, exhibit enhanced H-bonding compared with other silanols and alcohols as quantified using a ³¹P NMR probe. Evaluation of a Friedel–Crafts addition reaction shows that phenyl-POSS-triol is active as an H-bond donor catalyst whereas other POSS silanols studied are not. An in-depth kinetic study (using RPKA and VTNA) highlights the concentration-dependent H-bonding behavior of POSS-triols, which is attributed to intermolecular association forming an off-cycle dimeric species. Binding constants provide additional support for reduced H-bond ability at higher concentrations, which is attributed to competitive association. POSS-triol self-association disrupts H-bond donor abilities relevant for catalysis by reducing the concentration of active monomeric catalyst.     

A 300-GHz CMOS 7-by-7 Detector Array for Optics-less THz Imaging with Scan-less Target Object

Journal of Infrared, Millimeter, and Terahertz Waves - In this work, a 300-GHz 7?×?7 detector array based on a 65-nm Si CMOS technology has been developed and transmission imaging...