Retrograde Amnesia in Dementia: Comparison of HIV-Associated Dementia, Alzheimer's Disease, and Huntington's Disease.

Remote memory was assessed in persons with HIV-associated dementia (HIV-D), probable Alzheimer's disease (AD), and Huntington's disease (HD) and in healthy controls. The clinical groups were similar in overall dementia severity. Each clinical group exhibited impairments on remote memory tests relative to controls; however, temporally graded memory loss with selective preservation of older information was observed in the AD group but not the HD or HIV-D group. Analysis of cued retrieval indicated a preferential cuing benefit for the HIV-D and HD groups relative to the AD group. The similar pattern of remote memory performance demonstrated by the HIV-D and HD groups is a novel finding and suggests a subcortically mediated retrograde amnesia in HIV-D. The temporally graded pattern and the abnormal cued retrieval performance in the AD group are consistent with a consolidation deficit associated with extrahippocampal (cortical) and hippocampal damage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nano-Oncologicals: A Tortoise Trail Reaching New Avenues

Research efforts towards cancer therapeutics have resulted in the development of a variety of pharmacological molecules, including small synthetic molecules and biological drugs (RNA-based therapies and monoclonal antibodies—mAbs), intended to target tumor or immune-related cells, or their signaling mediators. The majority of them present important biopharmaceutical problems related to their difficulties for overcoming biological barriers and reach their targets. Nanotechnology has been, for more than 60 years, trying to solve these problems. As knowledge in drug discovery, molecular biology, and biomaterials advances, there has been significant progress in the adequate design of nanodelivery strategies that may significantly contribute to the exploitation of the new therapies. This review provides a critical overview of the current potential of nanotechnology to solve problems associated with the different categories of drugs. Starting with the general concept of passive and active targeting, it presents the distinct advantages that delivery technologies have shown to date for improving the therapeutic outcome of small drugs with cytotoxic activity, RNA- and mAb-based therapies. Moreover, it precisely describes the benefits of combining immunotherapies and nanotechnology. The most advanced technologies are put into perspective in relation to their translational pathway and the future avenues for nano-oncologicals.     

Modelling the Competitive Growth of Primary,Allotriomorphic, and Secondary Alpha in Ti-6Al-4V

Metallurgical and Materials Transactions A - The competitive formation of allotriomorphic α along the prior β grain boundaries, secondary α-phase and the growth of globular primary...     

Self‐Assembly of a Donor‐Acceptor Dyad Across Multiple Length Scales: Functional Architectures for Organic Electronics

Molecular dyads based on polycyclic electron donor (D) and electron acceptor (A) units represent suitable building blocks for forming highly ordered, solution‐processable, nanosegregated D‐A domains for potential use in (opto)electronic applications. A new dyad, based on alkyl substituted hexa‐peri‐hexabenzocoronene (HBC) and perylene monoimide (PMI) separated by an ethinylene linker, is shown to have a high tendency to self‐assemble into ordered supramolecular arrangements at multiple length scales: macroscopic extruded filaments display long‐range crystalline order, nanofiber networks are produced by simple spin‐coating, and monolayers with a lamellar packing are formed by physisorption at the solution‐HOPG interface. Moreover, highly uniform mesoscopic ribbons bearing atomically flat facets and steps with single‐molecule heights self‐assemble upon solvent‐vapor annealing. Electrical measurements of HBC‐PMI films and mesoscopic ribbons in a transistor configuration exhibit ambipolar transport with well balanced p‐ and n‐type mobilities. Owing to the increased level of order at the supramolecular level, devices based on ribbons show mobility increases of more than one order of magnitude.     

A comprehensive assessment of measurement equivalence in operations management

This paper provides a comprehensive framework for treating equivalence both prior to data collection and during subsequent analyses, and assesses the extent to which equivalence is considered in survey research in six leading empirical Operations Management (OM) journals (Decision Sciences, International Journal of Operations & Production Management, International Journal of Production Research, Journal of Operations Management, Management Science and Production and Operations Management). Measurement equivalence of latent variables in survey data is an important condition that should be met in order to meaningfully pool and/or compare data stemming from apparently heterogeneous sub-groups. We assess 465 survey articles from a six-year period from 2006 to 2011 and document these articles in relation to the four main stages of our comprehensive framework: identifying sources of heterogeneity; maximising equivalence prior to data collection; testing measurement equivalence after data collection; and dealing with partial and non-equivalence. We conclude that pooling of data from heterogeneous sub-groups is common practice in OM, but that awareness and testing of equivalence remains limited. Given these findings, we further elaborate the best practices detected in those few OM studies that do address equivalence in some way. We conclude that to improve the quality of OM survey research, authors, editors and reviewers should pay greater attention to equivalence, and we provide a pragmatic checklist of measurement equivalence issues across the four stages.     

Enhancing Osteoconduction of PLLA-Based Nanocomposite Scaffolds for Bone Regeneration Using Different Biomimetic Signals to MSCs

In bone engineering, the adhesion, proliferation and differentiation of mesenchymal stromal cells rely on signaling from chemico-physical structure of the substrate, therefore prompting the design of mimetic "extracellular matrix"-like scaffolds. In this study, three-dimensional porous poly-L-lactic acid (PLLA)-based scaffolds have been mixed with different components, including single walled carbon nanotubes (CNT), micro-hydroxyapatite particles (HA), and BMP2, and treated with plasma (PT), to obtain four different nanocomposites: PLLA + CNT, PLLA + CNTHA, PLLA + CNT + HA + BMP2 and PLLA + CNT + HA + PT. Adult bone marrow mesenchymal stromal cells (MSCs) were derived from the femur of orthopaedic patients, seeded on the scaffolds and cultured under osteogenic induction up to differentiation and mineralization. The release of specific metabolites and temporal gene expression profiles of marrow-derived osteoprogenitors were analyzed at definite time points, relevant to in vitro culture as well as in vivo differentiation. As a result, the role of the different biomimetic components added to the PLLA matrix was deciphered, with BMP2-added scaffolds showing the highest biomimetic activity on cells differentiating to mature osteoblasts. The modification of a polymeric scaffold with reinforcing components which also work as biomimetic cues for cells can effectively direct osteoprogenitor cells differentiation, so as to shorten the time required for mineralization.     

Inhibitory control following perinatal brain injury.

Evidence from developmental, lesion, and neuroimaging studies indicates that the prefrontal cortex plays a major role in executive abilities, including inhibitory control. Proficient executive performance, however, relies not only on the integrity of the prefrontal cortex but also on its interactions with other brain regions. In the current study, the authors focused on the effect that early damage to the white matter tracts interconnecting prefrontal and other brain regions has on inhibitory control. Data were collected from 13 children with bilateral spastic cerebral palsy and from a control group of 20 children with no history of neurologic compromise. Converging evidence from 3 separate paradigms is presented that strongly suggests these children experience impairments in inhibitory control. Findings are discussed within the context of current cognitive and neuroanatomical models of inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Photochemical degradation of polycyclic aromatic hydrocarbons in oil films

Photochemical processes affect the fate of spilled oil in the environment, but the relative contribution and kinetics of these degradation pathways are not fully constrained. To address this problem, we followed the weathering of No. 6 fuel oil by periodically sampling rocks covered with a film of oil from Buzzards Bay, MA after the April 2003 Bouchard 120 oil spill. Two sets of polycyclic aromatic hydrocarbon (PAH) isomers, benzo[a]pyrene (BAP) and benzo[e]pyrene (BEP), and benz[a]anthracene (BAA) and chrysene (CHR), were found to have very different disappearance rates in spite of their close structural similarity (kBAA/kCHR approximately 2.0, kBAP/kBEP approximately 2.2). This well-documented phenomenon is suspected to arise from differing capacity for direct photoreaction in the oil film. To investigate the validity of this assumption, we developed a model to estimate the contribution of direct photolysis to the loss of these PAHs from the oil. Newly determined PAH quantum yields demonstrate that the efficiency of phototransformation in hydrophobic media are 2 orders of magnitude lower (Phi' approximately 10(-5)) than in aqueous systems, and the thickness and light-attenuating properties of the oil film reduce the potential for photoreaction by up to 2 orders of magnitude. Given these limiting factors, direct photolysis cannot account for the complete removal of these PAHs (except BAP). Additional results suggest that singlet oxygen photodegradation pathways are not favored in hydrophobic media, as they are in some mineral-associated and aqueous systems. Our results indicate that photomediated reactions with other compounds in the oil mixture were responsible for PAH photodegradation in the oil film.