Factor-defined abilities in patients with unilateral brain lesions.

Administered a battery of 4 tests adapted from the structure of intellect model of differential abilities to 72 adults with right and left cerebral lesions and normals. Findings show that both brain-damaged groups exhibited slower response times than normals and that there was a relation between locus of the lesion and performance. However, results do not sufficiently demonstrate the advantage of factor-defined ability tests over tests of global intelligence and question the validity of these factor-defined tests in that they do not distinguish behaviors that are factorially distinct in normal populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of keratan sulfate oligosaccharides by electrospray ionization tandem mass spectrometry

Keratan sulfate (KS) is a glycosaminoglycan consisting of repeating disaccharide units composed of alternating residues of d-galactose and N-acetyl-d-glucosamine linked beta-(1-4) and beta-(1-3), respectively. In this study, electrospray ionization tandem mass spectrometry (ESI-MS/MS) was employed to identify keratan sulfate oligosaccharides. Two nonsulfated disaccharide isomers and two monosulfated disaccharide isomers were distinguished through MS/MS. In MS(1) spectra of multiply sulfated KS oligosaccharides, the charge state of the most abundant molecular ion equals the number of sulfates. Subsequent MS(2) and MS(3) spectra of mono-, di-, tri-, and tetrasulfated KS oligosaccharides and sialylated tetrasaccharides reveal diagnostic ions that can be used as fingerprint maps to identify unknown KS oligosaccharides. Based on the pattern of fragment ions, the compositions of an oligosaccharide mixture from shark cartilage KS and of two enzyme digests of bovine corneal KS were determined directly, without prior isolation of individual oligosaccharides by HPLC or other methods.     

Natural gas combined cycle with exhaust gas recirculation and CO2 capture at part-load operation

This paper aims to evaluate part-load operation of a natural gas combined cycle (NGCC) power plant with exhaust gas recirculation (EGR) and a CO₂ capture plant. Several studies have demonstrated the feasibility and the advantages of EGR at full load, but operation at part load is also important because it is a common condition when NGCC power plants are being used as backup for renewables. The results of this study show that the number of absorber trains is reduced from 4 to 3 with EGR. The efficiency of the NGCC plant with EGR was 0.5% points higher than a conventional NGCC at full load as a result of a higher CO₂ concentration in the flue gas. However, this efficiency advantage decreased as the load was reduced from 100% to 50%, with both cases presenting the same efficiency at 50% load. This means that there was no benefit from the effect of EGR at lower loads. The efficiency of a NGCC plant with EGR and CO₂ capture configuration decreased from 52.6% to 45.9% when the load was reduced from 100% to 50% compared with a conventional NGCC where the efficiency changed from 52.1% to 45.9%. It was concluded that a NGCC plant with EGR and CO₂ capture is viable, results in lower capital costs due to the smaller number of absorber trains and yields slightly higher efficiencies, for operation at part-load down to 50%.     

Acid gelation of low acyl gellan gum relevant to self-structuring in the human stomach

The aim of this study was to investigate the in vitro acid-induced gelation of low acyl gellan gum. Various metabolically relevant pH environments and hydrocolloid concentrations were investigated. These resulted in very different acid structures, which were characterised by texture analysis, with Young’s and bulk moduli and work of failure being reported. The structures of the acid gels were shown to depend upon the pH and hydrocolloid concentration (c) used during their production, with a maximum in gel strength between pH 3 and 4. Both the Young’s and bulk moduli data suggest that there is a critical concentration for gelation to occur, and both parameter values displayed a gradual increase (which appears to be lower than a c² dependency) as the gellan concentration was increased.     

Structure of heat-treated Nylon 6 and 6.6 fibers. I. The shrinkage mechanism

Nylon 6 and 6.6 fibers were submitted to thermal annealing in a wide range of temperatures (below and above their glass transition temperatures) under inert atmosphere and slack condition, allowing free shrinkage. The structural changes due to the heat settings were analyzed by several techniques (differential scanning calorimetry analysis, wide- and small-angle X-ray scattering, and birefringence). The results revealed different recrystallization responses of the fibers to the applied thermal annealings and consequently different shrinkage mechanisms. In the recrystallization of the Nylon 6 fibers were involved a generation of nuclei crystallites in the interfibrillar regions, as well as growth and perfection of these new crystallites and preexisting ones. But, recrystallization of the Nylon 6.6 fiber was accompanied only by growth and perfection of the preexisting crystals. The existence of the nuclei crystallites at temperatures of heat treatments above 120°C was the major commanding factor for the Nylon 6 fiber to undergo less shrinkage than the Nylon 6.6 fiber. These very tiny crystallites worked as crosslinking points that would impose restrictions in the mobility of the chains segments, inhibiting subsequent disorientation of the amorphous regions and consequently intense shrinkage, thus resulting in recrystallization in a preferred direction of the fiber axis. The Nylon 6.6 fiber experienced an instantaneous shrinkage at the annealing temperature around 70°C. That was the temperature necessary to release its hydrogen bonds and the starting temperature for presenting its major structural changes, including global disorientation of the amorphous and crystalline regions. Thus, its recrystallization occurred with no preferred orientation. Also, it was suggested that the occurrence of so different shrinkage mechanisms reside in the different crystalline morphology that these fibers originally possessed before the heat treatments. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 441–452, 1998     

Maximizing DNA loading on a range of gold nanoparticle sizes

We have investigated the variables that influence DNA coverage on gold nanoparticles. The effects of salt concentration, spacer composition, nanoparticle size, and degree of sonication have been evaluated. Maximum loading was obtained by salt aging the nanoparticles to approximately 0.7 M NaCl in the presence of DNA containing a poly(ethylene glycol) spacer. In addition, DNA loading was substantially increased by sonicating the nanoparticles during the surface loading process. Last, nanoparticles up to 250 nm in diameter were found have approximately 2 orders of magnitude higher DNA loading than smaller (13-30 nm) nanoparticles, a consequence of their larger surface area. Stable large particles are attractive for a variety of biodiagnostic assays.     

Identifying chemical changes in subchondral bone taken from murine knee joints using Raman spectroscopy

Application of Raman spectroscopy to analysis of subchondral bone is described. The effect of cartilage health on subchondral bone has been widely studied using radiological and histological methods; however, there is no method to directly assay mineral components. We present Raman spectra of femur condyles and observe mineral bands that arise from the subchondral bone. In two separate experiments, transgenic mouse models of early-onset osteoarthritis (OA) and lipoatrophy were compared to tissue from wild-type mice. Raman spectroscopy was used to identify chemical changes in the mineral of subchondral bone that may accompany or precede morphological changes that can be observed by histology. The transgenic mice were compared to age-matched wild-type mice. Subtle alterations in the mineral or collagen matrix were observed by Raman spectroscopy using established Raman markers such as the carbonate-to-phosphate ratio, mineral-to-matrix ratio (MTMR), and amide I ratio. The Raman microscope configuration enabled rapid collection of Raman spectra from the mineralized layer that lies under an intact layer of non-mineralized articular cartilage. The effect of the cartilage layer on collection of spectra is discussed. The technique proposed is capable of providing insight into the chemical changes that occur in subchondral bone on a molecular level.     

Posttraumatic stress symptoms among National Guard soldiers deployed to Iraq: Associations with parenting behaviors and couple adjustment.

Objective: In this article, we report findings from a 1-year longitudinal study examining the impact of change in posttraumatic stress disorder (PTSD) symptoms following combat deployment on National Guard soldiers' perceived parenting and couple adjustment 1 year following return from Iraq. Method: Participants were 468 Army National Guard fathers from a brigade combat team (mean age = 36 years; median deployment length = 16 months; 89% European American, 5% African American, 6% Hispanic American). Participants completed an in-theater survey 1 month before returning home from Operation Iraqi Freedom deployment (Time 1) and again 1 year postdeployment (Time 2). The PTSD Checklist—Military Version (PCL–M; Weathers, Litz, Herman, Huska, & Keane, 1993) was gathered at both times, and 2 items assessing social support were gathered at baseline only. At Time 2, participants also completed self-report measures of parenting (Alabama Parenting Questionnaire—Short Form; Elgar, Waschbusch, Dadds, & Sigvaldason, 2007), couple adjustment (Dyadic Adjustment Scale—7; Sharpley & Rogers, 1984; Spanier, 1976), parent–child relationship quality (4 items from the Social Adjustment Scale—Self-Report; Weissman & Bothwell, 1976), alcohol use (Alcohol Use Disorders Identification Test; Babor, Higgins-Biddle, Saunders, & Monteiro, 2001), and items assessing injuries sustained while deployed. Results: Structural equation modeling analyses showed that increases in PTSD symptoms were associated with poorer couple adjustment and greater perceived parenting challenges at Time 2 (both at p     

Accuracy of carotid strain estimates from ultrasonic wall tracking: a study based on multiphysics simulations and in vivo data

We used a multiphysics model to assess the accuracy of carotid strain estimates derived from a 1-D ultrasonic wall tracking algorithm. The presented tool integrates fluid-structure interaction (FSI) simulations with an ultrasound simulator (Field II), which allows comparison of the ultrasound (US) images with a ground truth. Field II represents tissue as random points on which US waves reflect and whose position can be updated based on the flow field and vessel wall deformation from FSI. We simulated the RF-signal of a patient-specific carotid bifurcation, including the blood pool as well as the vessel wall and surrounding tissue. Distension estimates were obtained from a wall tracking algorithm using tracking points at various depths within the wall, and further processed to assess radial and circumferential strain. The simulated data demonstrated that circumferential strain can be estimated with reasonable accuracy (especially for the common carotid artery and at the lumen-intima and media-adventitia interface), but the technique does not allow to reliably assess intra-arterial radial strain. These findings were supported by in vivo data of 10 healthy adults, showing similar circumferential and radial strain profiles throughout the arterial wall. We concluded that these deviations are present due to the complex 3-D vessel wall deformation, the presence of specular reflections and, to a lesser extent, the spatially varying beam profile, with the error depending on the phase in the cardiac cycle and the scanning location.