Transient increases in intracellular calcium and reactive oxygen species levels in TCam-2 cells exposed to microgravity

The effects of microgravity on functions of the human body are well described, including alterations in the male and female reproductive systems. In the present study, TCam-2 cells, which are considered a good model of mitotically active male germ cells, were used to investigate intracellular signalling and cell metabolism during exposure to simulated microgravity, a condition that affects cell shape and cytoskeletal architecture. After a 24 hour exposure to simulated microgravity, TCam-2 cells showed 1) a decreased proliferation rate and a delay in cell cycle progression, 2) increased anaerobic metabolism accompanied by increased levels of intracellular Ca(2+), reactive oxygen species and superoxide anion and modifications in mitochondrial morphology. Interestingly, all these events were transient and were no longer evident after 48 hours of exposure. The presence of antioxidants prevented not only the effects described above but also the modifications in cytoskeletal architecture and the activation of the autophagy process induced by simulated microgravity. In conclusion, in the TCam-2 cell model, simulated microgravity activated the oxidative machinery, triggering transient macroscopic cell events, such as a reduction in the proliferation rate, changes in cytoskeleton-driven shape and autophagy activation

The optical light curve of GRB 970228 refined

We present the R and V light curves of the optical counterpart of GRB 970228. A critical analysis of all the available data is made in light of the results achieved in the recent GRB Symposium held in Huntsville and by considering the latest information from the HST images on the underlying nebulosity.Comment: 3 pages, 2 .ps figures, Nuclear Physics style file espcrc2.sty included. To appear in the proceedings of the conference "The Active X-Ray Sky: Results from BeppoSAX and Rossi-XTE", Rome, Italy, 21-24 October, 1997. L. Scarsi, H. Bradt, P. Giommi and F. Fiore editors, Nuc. Phys. B Proc. Supp

Altered Kv2.1 functioning promotes increased excitability in hippocampal neurons of an Alzheimer's disease mouse model.

Altered neuronal excitability is emerging as an important feature in Alzheimer's disease (AD). Kv2.1 potassium channels are important modulators of neuronal excitability and synaptic activity. We investigated Kv2.1 currents and its relation to the intrinsic synaptic activity of hippocampal neurons from 3xTg-AD (triple transgenic mouse model of Alzheimer's disease) mice, a widely employed preclinical AD model. Synaptic activity was also investigated by analyzing spontaneous [Ca(2+)]i spikes. Compared with wild-type (Non-Tg (non-transgenic mouse model)) cultures, 3xTg-AD neurons showed enhanced spike frequency and decreased intensity. Compared with Non-Tg cultures, 3xTg-AD hippocampal neurons revealed reduced Kv2.1-dependent Ik current densities as well as normalized conductances. 3xTg-AD cultures also exhibited an overall decrease in the number of functional Kv2.1 channels. Immunofluorescence assay revealed an increase in Kv2.1 channel oligomerization, a condition associated with blockade of channel function. In Non-Tg neurons, pharmacological blockade of Kv2.1 channels reproduced the altered pattern found in the 3xTg-AD cultures. Moreover, compared with untreated sister cultures, pharmacological inhibition of Kv2.1 in 3xTg-AD neurons did not produce any significant modification in Ik current densities. Reactive oxygen species (ROS) promote Kv2.1 oligomerization, thereby acting as negative modulator of the channel activity. Glutamate receptor activation produced higher ROS levels in hippocampal 3xTg-AD cultures compared with Non-Tg neurons. Antioxidant treatment with N-Acetyl-Cysteine was found to rescue Kv2.1-dependent currents and decreased spontaneous hyperexcitability in 3xTg-AD neurons. Analogous results regarding spontaneous synaptic activity were observed in neuronal cultures treated with the antioxidant 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox). Our study indicates that AD-related mutations may promote enhanced ROS generation, oxidative-dependent oligomerization, and loss of function of Kv2.1 channels. These processes can be part on the increased neuronal excitability of these neurons. These steps may set a deleterious vicious circle that eventually helps to promote excitotoxic damage found in the AD brain

GRBs with optical afterglow and known redshift: a statistical study

We present a correlation between two intrinsic parameters of GRB optical afterglows. These are the isotropic luminosity at the maximum of the light curve (Lpeak) and the time-integrated isotropic energy (Eiso) radiated after the observed maximum. We test the correlation between the logarithms of (Eiso) and (Lpeak) and finally we value the effect of the different samples of GRBs in according with the first optical observation reduced to proper time.Comment: To be published in the proceedings of the conference "SWIFT and GRBs: Unveiling the Relativistic Universe", Venice, June 5-9, 200

Numerical simulation of physical systems in agri-food engineering

In agri-food engineering many complex problems arise in plant and process design. Specifically the designer has to deal with fluid dynamics, thermal or mechanical problems, often characterized by physics coupling, non-linearity, irregular geometry, anisotropy and in definitive rather high complexity. In recent years, the ever growing availability of computational power at low cost, made these problems more often approached with numerical simulation techniques. Mainly in terms of finite elements and finite volumes. In this paper the fundamentals of numerical methods are briefly recalled and a discussion about their possibility of application in the food and agricultural engineering is developed

Analisi carpologiche per la Vasca dello Specchio (Ferrara, XIV-XV sec. d.C.): metodologie d’indagine e risultati

Lo scavo condotto tra Corso Porta Reno e Via Vaspergolo, nel centro storico di Ferrara, ha portato alla luce un vano sotterraneo rettangolare denominato “Vasca dello Specchio”, utilizzato per lo smaltimento dei rifiuti tra XIV e XV secolo. Il riempimento, in parte già analizzato e pubblicato, è stato oggetto di nuove analisi carpologiche. I semi e i frutti, conservati prevalentemente per sommersione e in ottimo stato, sono complessivamente oltre 400.000 e la lista floristica comprende 168 taxa. La maggior parte dei reperti appartiene a piante coltivate/coltivabili o spontanee correlate all’uomo, che forniscono nuove informazioni sulla dieta vegetale e sull’ambiente urbano della Ferrara basso-medievale/rinascimentale. I reperti evidenziano anche pratiche domestiche e culinarie talora curiose