2,469 research outputs found
Protection of cortical cells by equine estrogens against glutamate-induced excitotoxicity is mediated through a calcium independent mechanism
BACKGROUND: High concentrations of glutamate can accumulate in the brain and may be involved in the pathogenesis of neurodegenerative disorders such as Alzheimer's disease. This form of neurotoxicity involves changes in the regulation of cellular calcium (Ca(2+)) and generation of free radicals such as peroxynitrite (ONOO(-)). Estrogen may protect against glutamate-induced cell death by reducing the excitotoxic Ca(2+ )influx associated with glutamate excitotoxicity. In this study, the inhibition of N-methyl-D-aspartate (NMDA) receptor and nitric oxide synthase (NOS) along with the effect of 17β-estradiol (17β-E(2)) and a more potent antioxidant Î(8), 17β-estradiol (Î(8), 17β-E(2)) on cell viability and intracellular Ca(2+ )([Ca(2+)](i)), following treatment of rat cortical cells with glutamate, was investigated. RESULTS: Primary rat cortical cells were cultured for 7â12 days in Neurobasal medium containing B27 supplements. Addition of glutamate (200 ÎźM) decreased cell viability to 51.3 Âą 0.7% compared to control. Treatment with the noncompetitive NMDAR antagonist, MK-801, and the NOS inhibitor, L-NAME, completely prevented cell death. Pretreatment (24 hrs) with 17β-E(2 )and Î(8), 17β-E(2 )(0.01 to 10 ÎźM) significantly reduced cell death. 17β-E(2 )was more potent than Î(8), 17β-E(2). Glutamate caused a rapid 2.5 fold increase in [Ca(2+)](i). Treatment with 0.001 to 10 ÎźM MK-801 reduced the initial Ca(2+ )influx by 14â41% and increased cell viability significantly. Pretreatment with 17β-E(2 )and Î(8), 17β-E(2 )had no effect on Ca(2+ )influx but protected the cortical cells against glutamate-induced cell death. CONCLUSION: Glutamate-induced cell death in cortical cultures can occur through NMDAR and NOS-linked mechanisms by increasing nitric oxide and ONOO(-). Equine estrogens: 17β-E(2 )and Î(8), 17β-E(2), significantly protected cortical cells against glutamate-induced excitotoxicity by a mechanism that appears to be independent of Ca(2+ )influx. To our knowledge, this is a first such observation. Whether the decrease in NOS related products such as ONOO(-), is a mechanism by which estrogens protect against glutamate toxicity, remains to be investigated. Estrogen replacement therapy in healthy and young postmenopausal women may protect against neurodegenerative diseases by these mechanisms
Tunneling spectroscopy studies of aluminum oxide tunnel barrier layers
We report scanning tunneling microscopy and ballistic electron emission
microscopy studies of the electronic states of the uncovered and
chemisorbed-oxygen covered surface of AlOx tunnel barrier layers. These states
change when chemisorbed oxygen ions are moved into the oxide by either flood
gun electron bombardment or by thermal annealing. The former, if sufficiently
energetic, results in locally well defined conduction band onsets at ~1 V,
while the latter results in a progressively higher local conduction band onset,
exceeding 2.3 V for 500 and 600 C thermal anneals
Responses to stress: Investigating the role of gender, social relationships, and touch avoidance in italy
Stress is a physiological response to internal and external events we call âstressorsâ. Response to the same daily stressors varies across individuals and seems to be higher for women. A possible explanation for this phenomenon is that women perceive sociality, relationships, and intimacyâ important sources of both stress and wellbeingâdifferently from how men experience them. In this study, we investigate how gender, attachment, and touch avoidance predict stress responses on a sample of 335 Italians (216 females; age = 35.82 Âą 14.32). Moreover, we analyze the network of relationships between these variables through multiple linear regression and exploratory network analysis techniques. The results recontextualize the role of gender in determining stress responses in terms of (lack of) confidence and touch avoidance toward family members; attitudes toward relationships seem to be the main determinants of stress responses. These results have implications for reducing stress in both clinical settings and at a social level
The Functional Psychotherapy Approach: A Process-Outcome Multiple Case Study
Objective: The present work aims to conduct the first naturalistic empirical investigation
of the process and outcome assessment of functional psychotherapy (FP) treatment.
The FP model of psychotherapy is rooted in psychoanalysis and integrates the verbal
communication approach founded on transference and countertransference dynamics
with the analysis of bodily processes.
Method: The study sample included ten patients recruited on a voluntary basis and
treated by clinicians in their private practices. Each patient received FP with an average
duration of 40 h (min 35 and max 42). Therapies had weekly sessions, were audiorecorded with the patientâs written consent, and lasted for an average of 10 months
(min 9 and max 12). Outcome and process tools included the Minnesota Multiphasic
Personality Inventory-2 (MMPI-2) and the Luborskyâs the Core Conflictual Relationship
Theme (CCRT), used to assess therapeutic benefit, and the Metacognition Assessment
Scale (MAS) and the Italian Discourse Attributes Analysis Program (IDAAP) system, used
to evaluate therapeutic benefit and process. The MMPI-2 was used also in the followup assessment.
Results: Results show that FP had a positive therapeutic outcome on the patients
assessed in this study, and that the therapeutic benefits were maintained over time.
Some specific features of the FP approach were found to contribute more than others
to the observed therapeutic benefits.
Conclusion: The current investigation constitutes a first step toward assessment of
the therapeutic effectiveness of FP. Future developments should apply the methodology
to a larger sample, possibly introducing different methodologies to enable detection of
specific bodily oriented processes and technique
Coupled FEM-DBEM Simulation of 3D Crack Growth under Fatigue Load Spectrum
Abstract Numerical predictions of fatigue crack growth under load spectrum are obtained by coupled FEM-DBEM approach. An initial part-through corner crack, in a pre-notched specimen undergoing a traction fatigue load, propagates becoming through the thickness. A two parameter crack growth law ("Unified Approach") is calibrated by in house made constant amplitude experimental tests and the crack growth retardation after an overload application is reproduced. The residual stresses responsible for such retardation are calculated by a sequence of elastic-plastic static FEM analysis; such stresses are then applied to the crack faces for the propagation simulation in a DBEM environment. A satisfactory agreement between numerical and experimental crack growth rates are displayed, for both part-through crack and through the thickness crack. This approach provide general modeling capabilities, with allowance for general crack front shape and fully automatic propagation
ThermalâMechanical FEM Analyses of a Liquid Rocket Engines Thrust Chamber
The Italian Ministry of University and Research (MIUR) funded the HYPROB Program to develop regeneratively cooled liquid rocket engines. In this type of engine, liquid propellant oxygenâmethane is used, allowing us to reach very good performances in terms of high vacuum specific impulse and high thrust-to-weight ratio. The present study focused on the HYPROB final ground demonstrator, which will be able to produce a 30 kN thrust in flight conditions. In order to achieve such a thrust level, very high chamber pressures (up to 50 bar) and consequently high thermal fluxes and gradients are expected inside the thrust chamber. Very complex and high-fidelity numerical FEM models were adopted here to accurately simulate the thermalâmechanical behavior of the thrust chamber cooling channels, accounting for plasticity, creep, and low-cycle fatigue (LCF) phenomena. The aim of the current work was to investigate the main failure phenomena that could occur during the thrust chamberâs service life. Results demonstrated that LCF is the main cause of failure. The corresponding number of loading cycles to failure were calculated accordingly
Experimental evaluation of the long-term creep deformations of epoxy resin
Abstract Adhesively bonded structures are widely used in many engineering fields for new structures and strengthening of existing ones. The failure of these joints are in some cases caused by long-term deformations. In this paper, an in house made experimental setup for investigating the creep behavior of epoxy resin specimens is presented. The test equipment consists of both conventional apparatus and a non-contact optical technique, Digital Image Correlation (DIC). Several tests were performed at different temperatures and the corresponding results were used for creep master curve construction by means of time-temperature superposition principle (TTSP)
The impact of light and temperature on chromatin organisation and plant adaptation
Light and temperature shape the developmental trajectory and morphology of plants. Changes in chromatin organisation and nuclear architecture can modulate gene expression and lead to short and long-term plant adaptation to the environment. Here, we review recent reports investigating how changes in chromatin composition, structure and topology modulate gene expression in response to fluctuating light and temperature conditions resulting in developmental and physiological responses. Furthermore, the potential application of novel revolutionary techniques such as RNA and padlock fluorescence in situ hybridization (FISH), and Hi-C to study the impact of environmental stimuli such as light and temperature on nuclear compartmentalisation in plants is discussed
Surrounded by the sea: re-investigating the villa maritima del Capo di Sorrento. Interim report
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.traveler passing by ship in front of the peninsula during the 1st c. A.D. would have marveled at a continuous chain of private villas lining the coast (figs. 1-2). Although evidence of these villas survives to the present day, our knowledge is mostly fragmentary due to the fact that many are buried beneath modern estates or have been swallowed by the sea. Between the village of Aequa (near Vico Equense) and the far side of the Sorrentine peninsula with its adjoining islets a total of 24 ruins have been identified as structures related to villae maritimae, commonly dated on the basis of their building techniques to between the Late Republican period and the start of the 2nd c. A.D. Key architectural features of these villas include different porticoes, panoramic exedras, artificial and natural grottos, galleries, nymphaea and piscinae. What all these elements have in common is that they are situated at the very point of contact with the sea and use the bedrock as the ground for construction.Peer Reviewe
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