Role of surface states in the Casimir force between semiconducting films

We present results of first principle calculations of the Casimir force between Si films of nanometric size, which show that it depends significantly upon the configuration of the surface atoms, and give evidence of the importance of surface states.Comment: to be published on J.Phys.

Evidence for a GABAergic system in rodent and human testis: Local GABA production and GABA receptors

The major neurotransmitter of the central nervous system, gamma-aminobutyric acid (GABA), exerts its actions through GABA(A), GABA(B) and GABA(C) receptors. GABA and GABA receptors are, however, also present in several non-neural tissues, including the endocrine organs pituitary, pancreas and testis. In the case of the rat testis, GABA appears to be linked to the regulation of steroid synthesis by Leydig cells via GABA(A) receptors, but neither testicular sources of GABA, nor the precise nature of testicular GABA receptors are fully known. We examined these points in rat, mouse, hamster and human testicular samples. RT-PCR followed by sequencing showed that the GABA-synthesizing enzymes glutamate decarboxylase (GAD) 65 and/or GAD67, as well as the vesicular GABA transporter vesicular inhibitory amino acid transporter (VIAAT/VGAT) are expressed. Testicular GAD in the rat was shown to be functionally active by using a GAD assay, and Western blot analysis confirmed the presence of GAD65 and GAD67. Interstitial cells, most of which are Leydig cells according to their location and morphological characteristics, showed positive immunoreaction for GAD and VIAAT/VGAT proteins. In addition, several GABA(A) receptor subunits (alpha1-3, beta1-3, gamma1-3), as well as GABAB receptor subunits R1 and R2, were detected by RT-PCR. Western blot analysis confirmed the results for GABA(A) receptor subunits beta2/3 in the rat, and immunohistochemistry identified interstitial Leydig cells to possess immunoreactive GABA(A) receptor subunits beta2/3 and alpha1. The presence of GABA(A) receptor subunit alpha1 mRNA in interstitial cells of the rat testis was further shown after laser microdissection followed by RT-PCR analysis. In summary, these results describe molecular details of the components of an intratesticular GABAergic system expressed in the endocrine compartment of rodent and human testes. While the physiological significance of this peripheral neuroendocrine system conserved throughout species remains to be elucidated, its mere presence in humans suggests the possibility that clinically used drugs might be able to interfere with testicular function. Copyright (C) 2003 S. Karger AG, Basel

Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic Mechanisms?

It is known that there must be some weak form of transport (called cool bottom processing, or CBP) acting in low mass RGB and AGB stars, adding nuclei, newly produced near the hydrogen-burning shell, to the convective envelope. We assume that this extra-mixing originates in a stellar dynamo operated by the differential rotation below the envelope, maintaining toroidal magnetic fields near the hydrogen-burning shell. We use a phenomenological approach to the buoyancy of magnetic flux tubes, assuming that they induce matter circulation as needed by CBP models. This establishes requirements on the fields necessary to transport material from zones where some nuclear burning takes place, through the radiative layer, and into the convective envelope. Magnetic field strengths are determined by the transport rates needed by CBP for the model stellar structure of a star of initially 1.5 solar mass, in both the AGB and RGB phases. The field required for the AGB star in the processing zone is B_0 ~ 5x10^6 G; at the base of the convective envelope this yields an intensity B_E < 10^4 G (approximately). For the RGB case, B_0 ~ 5x10^4 to 4x10^5 G, and the corresponding B_E are ~ 450 to 3500 G. These results are consistent with existing observations on AGB stars. They also hint at the basis for high field sources in some planetary nebulae and the very large fields found in some white dwarfs. It is concluded that transport by magnetic buoyancy should be considered as a possible mechanism for extra mixing through the radiative zone, as is required by both stellar observations and the extensive isotopic data on circumstellar condensates found in meteorites.Comment: 26 pages, 4 figures, accepted by Astrophysical Journa

Predictors of survival in progressive supranuclear palsy and multiple system atrophy: a systematic review and meta-analysis

Objective To undertake a systematic review and meta-analysis of studies that investigated prognostic factors and survival in patients with progressive supranuclear palsy (PSP) and multiple system atrophy (MSA). Methods Publications of at least 10 patients with a likely or confirmed diagnosis of PSP or MSA were eligible for inclusion. Methodological quality was rated using a modified version of the Quality in Prognostic Studies tool. For frequently examined prognostic factors, HRs derived by univariate and multivariate analysis were pooled in separate subgroups; other results were synthesised narratively and HRs could not be reported here. Results Thirty-seven studies presenting findings on 6193 patients (1911 PSP, 4282 MSA) fulfilled the inclusion criteria. We identified the following variables as unfavourable predictors of survival. In PSP, PSP-Richardson’s phenotype (univariate HR 2.53; 95% CI 1.69 to 3.78), early dysphagia and early cognitive symptoms. In MSA, severe dysautonomia and early development of combined autonomic and motor features but not MSA phenotype (multivariate HR 1.22; 95% CI 0.83 to 1.80). In PSP and MSA, survival was predicted by early falls (multivariate HR 2.32; 95% CI 1.94 to 2.77), the Neuroprotection and Natural History in Parkinson Plus Syndromes Parkinson Plus Score and the Clinical Global Impression Disease Severity Score but not sex (multivariate HR 0.93; 95% CI 0.67 to 1.28). There was conflicting evidence regarding the prognostic effect of age at onset and stridor. Conclusion Several clinical variables were strongly associated with shorter survival in PSP and MSA. Results on most prognostic factors were consistent across methodologically diverse studies; however, the lack of commonality of prognostic factors investigated is a significant limitation

Enhancing upper limb prosthetic embodiment through virtual reality with eye-tracking and vibrotactile feedback

The advances in bionic prosthetics yearly show impressive achievements in the effort to improve the motor capabilities and the quality of life of people facing the difficulties due to a limb amputation or agenesis. However, aligning the actual and the desired experience of using an artificial limb in daily activities constitutes an additional challenge. Indeed, several prosthetic users tend to abandon their bionic limbs because of (for instance) their lack of reliability and sensory feedback. Consequently, strategies for increasing the prosthetic technology acceptance are explored in literature, often referring to the phenomenon of the embodiment: the incorporation of an external object in the individual body scheme (the neurocognitive representation of one's body). Among the solutions for stimulating the prosthetic embodiment, the literature offers heterogeneous interactive trainings, often based on Virtual Reality (VR) settings. By exploiting the capability of digital environments to engage the user in repetitive exercises (as in the exergames) and to accurately elicit expected reactions (like the ones of the Rubber Hand Illusion, RHI), the study presented in this paper explores the use of immersive VR to enhance the sense of embodiment, focusing on one of its components, the body ownership - the sensation of owning the external object. The VR application developed for accomplishing this study includes a vibro-tactile feedback to increase the sensory engagement and facilitate the integration of a bionic upper limb - in this case the "Hannes" hand. In particular, the experiment compares two conditions: in one, the users (healthy subjects) use their gaze for attaching components of the digital limb after a certain dwell time, and evoking the vibro-tactile feedback; in the other condition, they must press a button with the other hand for completing the task without any dwell time. The two conditions are assessed using measures of body ownership, such as the proprioceptive drift (estimating the real hand position after a session for triggering the RHI for the actual prosthesis). The findings suggest that immersive VR can improve the acceptance and integration of prosthetic limbs, especially without fully entrusting the gaze control for the interaction: probably, this condition misdirected the cognitive resources for evoking the illusion of owning the digital hand, apparently a requiremennt for "embodying" the actual prosthesis. Preliminary results show this approach could help the bionic limb users with a novel tool to improve their prosthetic technology acceptance

mTORC1 is essential for early steps during Schwann cell differentiation of amniotic fluid stem cells and regulates lipogenic gene expression.

Schwann cell development is hallmarked by the induction of a lipogenic profile. Here we used amniotic fluid stem (AFS) cells and focused on the mechanisms occurring during early steps of differentiation along the Schwann cell lineage. Therefore, we initiated Schwann cell differentiation in AFS cells and monitored as well as modulated the activity of the mechanistic target of rapamycin (mTOR) pathway, the major regulator of anabolic processes. Our results show that mTOR complex 1 (mTORC1) activity is essential for glial marker expression and expression of Sterol Regulatory Element-Binding Protein (SREBP) target genes. Moreover, SREBP target gene activation by statin treatment promoted lipogenic gene expression, induced mTORC1 activation and stimulated Schwann cell differentiation. To investigate mTORC1 downstream signaling we expressed a mutant S6K1, which subsequently induced the expression of the Schwann cell marker S100b, but did not affect lipogenic gene expression. This suggests that S6K1 dependent and independent pathways downstream of mTORC1 drive AFS cells to early Schwann cell differentiation and lipogenic gene expression. In conclusion our results propose that future strategies for peripheral nervous system regeneration will depend on ways to efficiently induce the mTORC1 pathway

Physician practice patterns on the use of inferior vena cava filters in venous thromboembolism

Research lette

Rotigotine Objectively Improves Sleep in Parkinson’s Disease: An Open-Label Pilot Study with Actigraphic Recording

Sleep disturbances represent important predictors of poor quality of life (QoL) in Parkinson’s disease (PD). This open-label pilot study aimed to objectively assess, by means of actigraphic recording, effect of rotigotine on sleep in PD patients with self-reported sleep complaints. 15 PD patients underwent one-week actigraphic recording before (T0) and during (T1) rotigotine treatment, which was titrated to the dose subjectively improving motor symptoms (4–8 mg/24 h). Sleep disturbances, daytime sleepiness, cognitive performance, QoL, and depression were also evaluated with questionnaires. Actigraphic recordings showed a significant reduction in nocturnal motor activity and mean duration of wake episodes after sleep onset during rotigotine treatment compared to baseline. In 10 patients presenting objective evidence of poor sleep quality at T0 (sleep efficiency ≤ 85%), rotigotine also significantly improved other sleep parameters and further reduced nocturnal motor activity and mean duration of wake episodes. A significant decrease in number and duration of daytime sleep episodes was also observed at T1. Finally we confirmed that rotigotine significantly improves perceived sleep quality and QoL. Our study showed for the first time that rotigotine is associated with an objective improvement of nocturnal and diurnal sleep disturbances in PD patients with self-reported sleep complaints. This study is registered with AIFA-observational study registry number 12021

Rotigotine Objectively Improves Sleep in Parkinson's Disease: An Open-Label Pilot Study with Actigraphic Recording

Sleep disturbances represent important predictors of poor quality of life (QoL) in Parkinson\u2019s disease (PD).This open-label pilot study aimed to objectively assess, by means of actigraphic recording, effect of rotigotine on sleep in PD patients with self-reported sleep complaints. 15 PDpatients underwent one-week actigraphic recording before (T0) and during (T1) rotigotine treatment, which was titrated to the dose subjectively improving motor symptoms (4\u20138mg/24 h). Sleep disturbances, daytime sleepiness, cognitive performance, QoL, and depression were also evaluated with questionnaires. Actigraphic recordings showed a significant reduction in nocturnalmotor activity andmean duration of wake episodes after sleep onset during rotigotine treatment compared to baseline. In 10 patients presenting objective evidence of poor sleep quality at T0 (sleep efficiency 64 85%), rotigotine also significantly improved other sleep parameters and further reduced nocturnal motor activity and mean duration of wake episodes. A significant decrease in number and duration of daytime sleep episodes was also observed at T1. Finally we confirmed that rotigotine significantly improves perceived sleep quality and QoL. Our study showed for the first time that rotigotine is associated with an objective improvement of nocturnal and diurnal sleep disturbances in PD patients with self-reported sleep complaints.This study is registered with AIFAobservational study registry number 12021

An augmented and diminished reality exergame for investigating the embodiment of a prosthetic limb

Bionic limb prosthetics continue to face significant challenges in terms of artificial limb embodiment, often leading to prosthesis abandonment in patients. Following recent results in literature on digital trainings, this study investigates the impact of the visuo-attentive feedback of an Augmented/Diminished Reality (AR/DR) exergame on prosthetic embodiment. Two interaction paradigms were compared, i.e. a reference unrestricted interaction of a virtual prosthetic limb against a one in which the prosthesis and its interaction capability fades over time and requires the participant's visual-attention to reestablish it. Preliminary findings on non-amputees demonstrated hardship with the visuo-attentive approach which was associated with detrimental effects on the prothesis embodiment, possibly because of the re-allocation of cognitive resources that are necessary to establish the process of body ownership