Improved semiclassical dynamics through adiabatic switching trajectory sampling.

We introduce an improved semiclassical dynamics approach to quantum vibrational spectroscopy. In this method, a harmonic-based phase space sampling is preliminarily driven toward non-harmonic quantization by slowly switching on the actual potential. The new coordinates and momenta serve as initial conditions for the semiclassical dynamics calculation, leading to a substantial decrease in the number of chaotic trajectories to deal with. Applications are presented for model and molecular systems of increasing dimensionality characterized by moderate or high chaoticity. They include a bidimensional Henon-Heiles potential, water, formaldehyde, and methane. The method improves accuracy and precision of semiclassical results and it can be easily interfaced with all pre-existing semiclassical theories.

Non-specific interstitial pneumonia and features of connective tissue disease: What are the consequences of a different point of view?

Patients with Interstitial Lung Disease (ILD) without a definitive diagnosis of connective tissue diseases (CTD) were historically described as Undifferentiated Connective Tissue Disease (UCTD-ILD). Recently a new classification, Interstitial Pneumonia with Autoimmune Features (IPAF), has been proposed. Aim of this study was to describe the prevalence, clinical characteristics and prognostic factors of UCTD and IPAF subjects in a cohort of Non-Specific Interstitial Pneumonia (NSIP) patients. This retrospective, observational study enrolled 102 adult patients characterized by NSIP pattern on High Resolution Computed Tomography, without a specific diagnosis of CTD. Three groups were identified according to patients' characteristics: IPAF, UCTD or idiopathic NSIP (iNSIP). Forty percent, 27% and 55% of patients showed diagnostic criteria for IPAF, UCTD and iNSIP, respectively. No significant differences in age, gender, smoking habit, pulmonary function tests and three-year survival rate were observed among study groups. IPAF patients with antisynthetase antibodies positivity, in comparison to IPAF without antisynthetase antibodies positivity, showed more frequently an acute onset (44% vs 9%, p<0.012). The presence of autoimmune features seems not to be associated with better outcomes in NSIP patients. IPAF criteria seem to be more representative than UCTD criteria in identifying patients with autoimmune features. Further studies are needed to verify if IPAF should include patients with positive antisynthetase serology.

Echinoderm regeneration: an in vitro approach using the crinoid Antedon mediterranea.

Among echinoderms, crinoids are well known for their remarkable regenerative potential. Regeneration depends mainly on progenitor cells (undifferentiated or differentiated), which migrate and proliferate in the lesion site. The crucial role of the "progenitor" elements involved in the regenerative processes, in terms of cell recruitment, sources, and fate, is a central problem in view of its topical interest and biological implications. The spectacular regenerative potential of crinoids is used to replace lost internal and external organs. In particular, the process of arm regeneration in the feather star Antedon mediterranea is the regeneration model most extensively explored to date. We have addressed the morphological and functional characterization of the cell phenotypes responsible for the arm regenerative processes by using an in vitro approach. This represents the first successful attempt to culture cells involved in crinoid regeneration. A comparison of these results with others from previous in vivo investigations confirms the diverse cell types contributing to regeneration and underscores their involvement in migration, proliferation, and dedifferentiation processes.

The reaction of the sponge Chondrosia reniformis to mechanical stimulation is mediated by the outer epithelium and the release of stiffening factor(s).

Although sponges are still often considered to be simple, inactive animals, both larvae and adults of different species show clear coordination phenomena triggered by extrinsic and intrinsic stimuli. Chondrosia reniformis, a common Mediterranean demosponge, lacks both endogenous siliceous spicules and reinforcing spongin fibers and has a very conspicuous collagenous mesohyl. Although this species can stiffen its body in response to mechanical stimulation when handled, almost no quantitative data are available in the literature on this phenomenon. The present work was intended to quantify the dynamic response to mechanical stimulation both of intact animals and isolated tissue samples in order to evaluate: (i) the magnitude of stiffening; (ii) the relationship between the amount of stimulation and the magnitude of the stiffening response; (iii) the ability of the whole body to react to localized stimulation; (iv) the possible occurrence of a conduction mechanism and the role of the exopinacoderm (outer epithelium). Data on mesohyl tensility obtained with mechanical tests confirmed the difference between stimulated and non-stimulated isolated tissue samples, showing a significant relationship between ectosome stiffness and the amount of mechanical stimulation. Our experiments revealed a significant difference in tensility between undisturbed and maximally stiffened sponges and evidence of signal transmission that requires a continuous exopinacoderm. We also provide further evidence for the presence of a chemical factor that alters the interaction between collagen fibrils, thereby changing the mechanical properties of the mesohyl.