Sonographic demonstration of hepatic venous gas in mesenteric arterial thrombosis

Hepatic portal venous gas is an ominous prognostic sign in bowel necrosis from mesenteric arterial occlusion. Ultrasonic examination is a sensitive and accurate method of demonstrating portal venous gas. We describe a case where the ultrasonic diagnosis of portal venous gas led to the rapid diagnosis of bowel infarction. Ultrasound is an appropriate emergency examination in all patients with suspected mesenteric artery occlusion.     

Social Capital in Romanian Old People: Meanings and Opportunities for Health

Romanian pensioners are among the poorest in the European Union, making them a vulnerable group in terms of health and well-being. Social capital could act as a buffer and protect old people from health inequalities. Although the percentage of old persons has increased in Romania, little is known about their social capital, namely their social networks, their engagement in the community, their perceptions of residential areas and norms of trust and reciprocity. The present study set out to explore the structure and meanings of social capital in Romanian old people, namely the structural, cognitive and behavioural aspects of social capital in old Romanians, as well as the linking, bonding and bridging dimensions of social capital. Semi-structured interviews were conducted with 8 men and 6 women, aged 60 to 69. Data were analyzed using thematic analysis. All in all, Romanian pensioners display a lack of linking and bridging social capital. The most important social structure is the family, which provides both emotional and financial support. Norms of trust and reciprocity function only within the family but not the community. One of the main themes was lack of trust in the community and state institutions and reluctance to engage in community affairs as this is perceived to be the role of younger people. Rural areas are perceived as friendlier and more trustworthy and seen as an ideal residential area. Starting from these findings, interventions can be designed to increase linking, bridging and bonding social capital in old persons and create age-friendly environments.     

Experimental Methods for Improved Spatial Control of Thermal Lesions in Magnetic Resonance-Guided Focused Ultrasound Ablation

Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU, or MRgFUS) is a hybrid technology that was developed to provide efficient and tolerable thermal ablation of targeted tumors or other pathologic tissues, while preserving the normal surrounding structures. Fast 3-D ablation strategies are feasible with the newly available phased-array HIFU transducers. However, unlike fixed heating sources for interstitial ablation (radiofrequency electrode, microwave applicator, infra-red laser applicator), HIFU uses propagating waves. Therefore, the main challenge is to avoid thermo-acoustical adverse effects, such as energy deposition at reflecting interfaces and thermal drift of the focal lesion toward the near field. We report here our investigations on some novel experimental solutions to solve, or at least to alleviate, these generally known tolerability problems in HIFU-based therapy. Online multiplanar MR thermometry was the main investigational tool extensively used in this study to identify the problems and to assess the efficacy of the tested solutions. We present an improved method to cancel the beam reflection at the exit window (i.e., tissue-to-air interface) by creating a multilayer protection, to dissipate the residual HIFU beam by bulk scattering. This study evaluates selective de-activation of transducer elements to reduce the collateral heating at bone surfaces in the far field, mainly during automatically controlled volumetric ablation. We also explore, using hybrid US/MR simultaneous imaging, the feasibility of using disruptive boiling at the focus, both as a far-field self-shielding technique and as an enhanced ablation strategy (i.e., boiling core controlled HIFU ablation).     

Influence of Random Plasmonic Metasurfaces on Fluorescence Enhancement

One of the strategies employed to increase the sensitivity of the fluorescence-based biosensors is to deposit chromophores on plasmonic metasurfaces which are periodic arrays of resonating nano-antennas that allow the control of the electromagnetic field leading to fluorescence enhancement. While artificially engineered metasurfaces realized by micro/nano-fabrication techniques lead to a precise tailoring of the excitation field and resonant cavity properties, the technological overhead, small areas, and high manufacturing cost renders them unsuitable for mass production. A method to circumvent these challenges is to use random distribution of metallic nanoparticles sustaining plasmonic resonances, which present the properties required to significantly enhance the fluorescence. We investigate metasurfaces composed of random aggregates of metal nanoparticles deposited on a silicon and glass substrates. The finite difference time domain simulations of the interaction of the incident electromagnetic wave with the structures reveals a significant enhancement of the excitation field, which is due to the resonant plasmonic modes sustained by the nanoparticles aggregates. We experimentally investigated the role of these structures in the fluorescent behaviour of Rhodamine 6G dispersed in polymethylmethacrylate finding an enhancement that is 423-fold. This suggests that nanoparticle aggregates have the potential to constitute a suitable platform for low-cost, mass-produced fluorescent biosensors.     

Langmuir Probe Perturbations during In Situ Monitoring of Pulsed Laser Deposition Plasmas

The recent advancements in pulsed laser deposition (PLD) control via plasma diagnostics techniques have been positive and raised questions on the limitation of some techniques, such as the Langmuir probe (LP). The particularities of laser-produced plasma can lead to incorrect interpretation of collected electrical signal. In this paper, we explored the limitations of LP as a technique for in situ PLD control by performing investigations on several metallic plasmas, expanding in various Ar atmosphere conditions. Sub-microsecond modulation was seen in the reconstructed IV characteristics attributed to non-equilibrium dynamics of the ejected charges. A perturbative regime was recorded for Ar pressures higher than 2 Pa, where ionic bursts were observed in the electron saturation region. This perturbation was identified as a plasma fireball. A non-linear multifractal model was developed here to explore these new regimes of the LP. The strange attractors characterizing each fireball were reconstructed, and their evolution with the Ar pressure is discussed. Both short- and long-time non-linear behavior were correlated via probe bias, and the pressure effect on the strange attractor’s defining the fireball-like behavior was investigated. A good correlation was noticed between the simulated data and experimental findings.     

Risk perception moderates how intentions are translated into sunscreen use

Planning is supposed to mediate between intention and behavior. The study examines whether such a mediation also exists in the context of sunscreen use. Moreover, the question is raised whether health risk perception might moderate such a mechanism. A longitudinal online study was conducted with three measurement points in time. Sunscreen use, intention, planning, and risk perception were assessed. A sample of 154 individuals was analyzed by hierarchical regression procedures in terms of moderated mediation. Planning partially mediated the intention-behavior relationship, and risk perception operated as a moderator. The moderator effect was negative, implying that low risk perception in conjunction with high intention was a prerequisite for planning, and, thus, for the mediation by planning. Low risk perception reflects health-specific optimism which can be a facilitator of health behavior change, in this case the change of sunscreen use from Time 1 to Time 3.     

Elucidation of cell secretion: pancreas led the way.

Secretion is a basic process in all cells and is required for several important functions such as neurotransmission, the secretion of digestive juices from the exocrine pancreas and the release of hormones from endocrine and neuroendocrine cells. Due to these important functions, the mechanism of cell secretion has been intensely investigated for over half a century. However, it is only in the last decade, with the discovery of a new cellular structure, the 'porosome' or 'fusion pore', and the elucidation of SNARE-induced membrane fusion, that has finally provided us with an understanding of cell secretion at the molecular level. The 'porosome', a supramolecular structure at the cell plasma membrane, was first discovered in the exocrine pancreas, and subsequently in endocrine/neuroendocrine cells and in neurons. The structure and dynamics of the 'porosome' in live cells at nanometer resolution and in real-time, its composition and functional reconstitution in lipid membrane, have all been determined. These findings have fundamentally changed our understanding of cell secretion and provide a clear understanding of this highly regulated process in cells.     

Growth rate analysis of lung metastases appearing 18 years after resection of cutaneous adenoid cystic carcinoma. Case report and review of the literature.

Growth rate analysis of lung metastases of a cutaneous adenoid cystic carcinoma, which appeared 18 years after the resection of the primary tumor from the scalp is presented. The doubling times of the metastases were long compared with that of other lung metastases. They were 22 months for the metastasis in the right lung and 70 months for the metastasis in the left lung, with a shortening of the doubling time in the left side to 10.4 months in the last 4 months of observation. Backward extrapolation showed that the metastases to the lung were disseminated before the diagnosis and surgical resection of the primary tumor. To our knowledge, this is the third reported case of lung metastases from a cutaneous adenoid cystic carcinoma out of 25 documented cases. We present a review of the literature and discuss the clinical implications of our findings.     

Effect of activators and the phosphodiesterase inhibitors pentoxifylline and enoximone on the deformability of neutrophils in neonates and adults

BACKGROUND: Stimulated polymorphonuclear leukocytes (PMN) are extremely rigid compared to resting PMN. They may obstruct narrow vessels and contribute to ischaemic organ injury. Deformability is a prerequisite for both active and passive movement in the microcirculation. AIM: The investigation was designed to study whether stimulators and inhibitors of stimulation show different effects on deformability of neonatal and adult PMN. METHODS: Deformability of PMN was assessed by complete aspiration of a PMN into a micropipette with an internal diameter of 5 microm. Blood samples from 20 neonates and 20 adults were studied before and after stimulation with N-formyl-methionyl-leucyl-phenylalanine (fMLP), interleukin-8 (IL-8) or tumour necrosis factor-alpha (TNF-alpha). Moreover, effects of the phosphodiesterase inhibitors Pentoxifylline (PTX) and Enoximone on the deformability of stimulated PMN were investigated. RESULTS: fMLP, IL-8 and TNF-alpha significantly delayed aspiration times of PMN in relation to the concentrations of the stimulators. The addition of PTX or Enoximone to stimulated PMN increased the deformability up to 60% depending on the concentration of the inhibitors. No significant differences in the aspiration times were found between neonatal and adult PMN at any of the experimental conditions after activation with the three stimulators and treatment with the two inhibitors. CONCLUSION: Neonatal and adult PMN show similar reduction of passive deformability when stimulated with either fMLP, IL-8 or TNF-alpha compared to resting PMN and a similar improvement of deformability in response to PTX or Enoximone.