Phenotyping Metastatic Brain Tumors Applying Spectrochemical Analyses: Segregation of Different Cancer Types

Metastatic brain tumors represent a significant proportion of tumors identified intraoperatively. A rapid diagnostic method, circumventing the need for histopathology studies, could prove clinically useful. As many spectroscopic studies have shown ability to differentitate between different tumor types, this technique was evaluated for use within metastatic brain tumors. Spectrochemical approaches [Raman and attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) spectroscopy] were applied to determine how readily they may identify the primary site for the metastatic tumor. Metastases were from primary adenocarcinomas of lung (n?=?7) and colorectum (n?=?7), and for comparison, metastatic melanoma (n?=?7). The objective was to determine if Raman or ATR-FTIR spectroscopy could delineate the origin of the primary tumor. The results demonstrate that there are marked similarities between the two adenocarcinoma groups and whilst Raman and ATR-FTIR can distinguish the three groups with limited success, classification accuracy is greatly improved when combining the adenocarcinoma groups. The use of such techniques in the clinical setting is more likely to be found intraoperatively, determining the presence of a tumor and suggesting the tumor class; however, traditional histopathology would still be needed to identify the primary origin of the tumor.     

Substituent effects on the amination of racemic allyl carbonates using commercially available chiral rhodium catalysts

In the presence of commercially available chiral rhodium catalysts, a competitive benzylamination of racemic allyl carbonates, substituted with p-X-Ph groups, shows that the reaction proceeds faster with substituents (X) that are more electron-withdrawing. Mechanistic implications of these results are discussed.     

An adhesive bond state classification method for a composite skin-to-spar joint using chaotic insonification

The combination of chaotically amplitude-modulated ultrasonic waves and time series prediction algorithms has shown the ability to locate and classify various bond state damage conditions of a composite bonded joint. This study examines the ability of a new two-part supervised learning classification scheme not only to classify disbond size but also to classify whether a bond for which there is no baseline data is undamaged or has some form of disbond. This classification is performed using data from a similarly configured composite bond for which baseline data are available. The test structures are analogous to a wing skin-to-spar bonded joint. An active excitation signal is imparted to the structure through a macro fiber composite (MFC) patch on one side of the bonded joint and sensed using an equivalent MFC patch on the opposite side of the joint. There is an MFC actuator/sensor pair for each bond condition to be identified. The classification approach compares features derived from an autoregressive (AR) model coefficient vector cross-assurance criterion.     

Analysis of the bonding in alkali-cation/Rg complexes (Rg = He–Xe) using a simple model potential

We have applied the model-potential analysis of Breckenridge and co-workers to the Alk⁺/Rg systems, where Alk is an alkali atom and Rg is a rare-gas atom. Three spectroscopic constants, R_e, D_e and ω_e, are employed to obtain the potential, with fitted parameters being the A and b repulsive Born–Mayer potential parameters, and the effective charge on the metal center, Z. From the analysis, it is concluded that all of these systems can be described in physical terms, with the calculated charge on the metal center being very close to 1.00. Interestingly the effective charge on the metal atom from such model-potential calculations is consistently very slightly greater than 1.00. We discuss and investigate several possible sources for this small anomaly, including a minor breakdown of the model at small internuclear separations, where the “lengths” of the induced multipoles become significant compared to the internuclear separation R. Despite this small breakdown, overall the model is remarkably successful in reproducing high-level ab initio curves for the titular complexes over wide ranges of internuclear distances.     

Nanoindentation of biodegradable cellulose diacetate‐graft‐poly(L‐lactide) copolymers: Effect of molecular composition and thermal aging on mechanical properties

Nanoindentation of cellulose diacetate‐graft‐poly(lactide)s (CDA‐g‐PLLAs) synthesized by ring opening graft copolymerization of L ‐lactide in bulk onto the residual hydroxyl positions on CDA were conducted to investigate the effect of the molecular composition and thermal aging on mechanical properties and creep behavior. Continuous stiffness measurement (CSM) technique was used to obtained hardness and elastic modulus. These material properties were expressed as a mean value from 100 to 300 nm depths and an unloading value at final indentation depth. The hardness and elastic modulus in all CDA‐g‐PLLAs were higher than those in pure CDA, indicating that the introduction of PLLA increases the hardness and elastic modulus. With an increase of crystallinity by thermal aging, the hardness and elastic modulus were increased in both CDA‐g‐PLLA and PLLA. The creep test performed by CSM showed that the creep strain of CDA was decreased by the grafting of PLLA. Thermal aging decreased the creep strain of CDA‐g‐PLLA and PLLA. With an increase of holding time, hardness was decreased, whereas elastic modulus was kept almost constant. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1114–1121, 2007