568 research outputs found
Electrical Characterisation of Ultra-thin SAM Structures
The way of reduction of metal oxyde semiconductor (MOS) structures is going
to reach limitations and new devices have to be explored as an alternative to
MOS technology. Molecular electronic and more particularly
self-assembly-molecular technique on silicon substrate gives interesting
results as seen in the literature. We are going to study n-alkyltrichlorosilane
grafting on oxidised silicon, characterise it macroscopically with ellipsometer
and goniometry measurements, and down to microscopic scale with atomic force
microscopy. Once the uniformity of the monolayer is verified (roughness of few
Angstr\"oms) we have tested a sputtering method deposition to form aluminium
dots onto the surface. Also metal-insulator-semiconductor diodes are tested
measuring both leakage current between gate and substrate and
capacitance-voltage. The sputtering method deposition can be improved in order
to decrease the gate leakage current and we would like to test another
evaporation method. Further application we want to study is gas sensors using
conjugated organic films or synthetic polymers and concerns the drift current
with gas absorption.Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
Effect of gonococcal lipooligosaccharide variation on human monocytic cytokine profile
BACKGROUND: Neisseria gonorrhoeae is an obligate human pathogen that causes significant worldwide morbidity. N. gonorrhoeae expresses lipooligosaccharide (LOS), a phase variable molecule that plays an important role during pathogenesis of the organism. Alteration in the structure of gonococcal LOS correlates with altered disease presentation. In addition, LOS sialylation occurs readily in vivo, though the role of this sialylation during disease is unknown. RESULTS: Challenge of human monocytes with purified LOS preparations isolated from strains expressing distinct structurally defined LOSs resulted in identical production of the proinflammatory cytokines tumor necrosis factor alpha (TNFα) and interleukin-12 (IL-12). Similar results were seen when monocytes were challenged with either live or gentamicin-killed whole cell gonococcal variants expressing these LOS structures, although greater cytokine production was observed in comparison with challenge by purified LOS. Challenge of a human primary monocyte model with distinct LOS variants resulted in similar production of TNFα, IL-12, interleukin-10 (IL-10), and interleukin-8 (IL-8). A cytokine array was employed to allow measurement of a broad range of cytokines in samples challenge with gonococcal LOS variants as well as variants expressing sialylated LOS. Challenge of primary monocytes with sialylated gonococci was shown to elicit the production of more MCP-2 (monocyte chemoattractant protein-2) in comparison with challenge by unsialylated gonococci. CONCLUSION: We demonstrated that while alterations in the carbohydrate moiety of LOS do not impact the production of most cytokines by human monocytes, whole-cell bacterial challenge is more stimulatory than challenge with purified LOS, implying that other gonococcal cell surface antigens are important for the elicitation of cytokines. Challenge with gonococci expressing sialylated LOS resulted in elicitation of more of the chemokine MCP-2 from challenged cells in comparison with gonococci expressing unsialylated LOS. As MCP-2 is an important chemoattractant, this indicates that in vivo sialylation may play an important role during the pathogenesis of N. gonorrhoeae
Performance Evaluation of a Satellite Communication-based MEC architecture for IoT applications
New scenarios and use cases are raising following the birth of the fifth generation of mobile communications. The Internet of Things (IoT) is one of the main use cases which are growing, leading to a massive amount of data that need to be exchanged throughout the Internet. Satellite communication networks are essential in remote and isolated environments and can support fully connected environments by offloading the terrestrial infrastructure concerning delay–tolerant traffic flows. However, satellite network resources are limited and expensive, so they need to be carefully used in order to avoid waste and satisfy the required user performance. The multi-access edge computing (MEC) concept can be exploited in this context to allow data preprocessing at the edge, i.e., close to the users, so reducing the amount of data that has to traverse the backhaul satellite link and, in some cases, reducing data delivery times. This article analyses the performance of a satellite architecture in the IoT framework highlighting the advantages brought by MEC, also including data aggregation and compression techniques
Small satellites and CubeSats: survey of structures, architectures, and protocols
The space environment is still challenging but is becoming more and more attractive for an increasing number of entities. In the second half of the 20th century, a huge amount of funds was required to build satellites and gain access to space. Nowadays, it is no longer so. The advancement of technologies allows producing very small hardware components able to survive the strict conditions of the outer space. Consequently, small satellites can be designed for a wide set of missions keeping low design times, production costs, and deployment costs. One widely used type of small satellite is the CubeSat, whose different aspects are surveyed in the following: mission goals, hardware subsystems and components, possible network topologies, channel models, and suitable communication protocols. We also show some future challenges related to the employment of CubeSat networks
The Stroke-Induced Increase of Somatostatin-Expressing Neurons is Inhibited by Diabetes: A Potential Mechanism at the Basis of Impaired Stroke Recovery
Type 2 diabetes (T2D) hampers recovery after stroke, but the underling mechanisms are mostly unknown. In a recently published study (Pintana et al. in Clin Sci (Lond) 133(13):1367\u20131386, 2019), we showed that impaired recovery in T2D was associated with persistent atrophy of parvalbumin+ interneurons in the damaged striatum. In the current work, which is an extension of the abovementioned study, we investigated whether somatostatin (SOM)+ interneurons are also affected by T2D during the stroke recovery phase. C57Bl/6j mice were fed with high-fat diet or standard diet (SD) for 12\ua0months and subjected to 30-min transient middle cerebral artery occlusion (tMCAO). SOM+ cell number/density in the striatum was assessed by immunohistochemistry 2 and 6\ua0weeks after tMCAO in peri-infarct and infarct areas. This was possible by establishing a computer-based quantification method that compensates the post-stroke tissue deformation and the irregular cell distribution. SOM+ interneurons largely survived the stroke as seen at 2\ua0weeks. Remarkably, 6\ua0weeks after stroke, the number of SOM+ interneurons increased (vs. contralateral striatum) in SD-fed mice in both peri-infarct and infarct areas. However, this increase did not result from neurogenesis. T2D completely abolished this effect specifically in the in the infarct area. The results suggest that the up-regulation of SOM expression in the post-stroke phase could be related to neurological recovery and T2D could inhibit this process. We also present a new and precise method for cell counting in the stroke-damaged striatum that allows to reveal accurate, area-related effects of stroke on cell number
Efficiency in Multi-objective Games
In a multi-objective game, each agent individually evaluates each overall
action-profile on multiple objectives. I generalize the price of anarchy to
multi-objective games and provide a polynomial-time algorithm to assess it.
This work asserts that policies on tobacco promote a higher economic
efficiency
Advanced hemostasis in axillary lymph node dissection for locally advanced breast cancer. New technology devices compared in the prevention of seroma formation
Background: Breast cancer is the most frequent neoplasm in women. Axillary lymph nodes dissection represents the treatment of choice in locally advanced breast cancer for prognostic and curative purposes. Seroma formation, an abnormal collection of fluid in the dead space of the axilla, is described in Literature with a wide range of incidence (3-85%). It is a source of significant morbidity and discomfort. The aim of the study is to compare the different haemostasis devices used in breast surgery, investigating the eventual superiority of an instrument among the others in terms of intraoperative and postoperative outcome, especially of seroma formation. Methods: Clinical cases of female patients undergone axillary lymph nodes dissection for local advanced breast cancer between January 2013 and July 2017 at the Surgery Unit of University of Campania "Luigi Vanvitelli" were retrospectively reviewed. Patients were divided into four groups, according to device utilized during surgery: Electrocautery, Harmonic Scalpel, LigaSure and Thunderbeat. All patients underwent II level axillary lymph nodes dissection associated to radical mastectomy or quadrantectomy. Results: One hundred consecutives patients were enrolled in the study. Intra-operative blood loss resulted statistically significant different (P < 0,01) between the Electrocautery group (94,7 ml) and the Thunderbeat group (57,2 ml), while the Harmonic Scalpel group and the Ligasure group, despite presented a lower amount of blood loss, did not differ significantly. Drainage volume resulted significantly lower (P = 0,002) in the comparison between the Electrocautery group and the Thunderbeat group; the Ligasure group and Harmonic Scapel group showed no difference between them and Electrocautery group. About the seroma formation, the Electrocautery group resulted affected by the highest seroma formation rate (64%). Seroma incidence in Harmonic Scalpel group was 24%, in Ligasure group was 44%, while Thunderbeat group showed the lowest presentation of seroma with 16%. Conclusions: In patients affected by breast cancer requiring axillary lymphnodes dissection, the use of advanced hemostasis devices is highly desirable. Among the non-traditional tools, Thunderbeat resulted to be superior in terms of reduction of intra-operative blood loss and post-operative drainage output, moreover associated to a substantial reduction of postoperative seroma incidence
Association between Hashimoto's thyroiditis and papillary thyroid carcinoma: A retrospective analysis of 305 patients
Background: The association between Hashimoto's thyroiditis (HT) and papillary thyroid carcinoma (PTC) is a controversial question that is still under debate, its pathological significance and the eventual clinical implications of this association remaining unclear. Methods: The data regarding 305 patients were retrospectively analyzed. The patients were divided in two different groups. A first group made up of 142 patients undergoing surgery for differentiated thyroid carcinoma was compared to a control group of 142 analogous subjects operated for normofunctioning goiter. A second group was made up of 163 patients who had undergone total thyroidectomy (TT) with pre-operative diagnosis of HT. Results: In the first group of patients an association with HT was found in 28,6% of the patients with final histopathological diagnosis of PTC versus 7,7% of the patients with histopathological diagnosis of multinodular goiter, which was a significant difference (p < 0.001). In the second group, the association with PTC was found in 43 (40,2%) cases of HT nodular variant and in 3 cases (8,1%) of HT diffuse variant (p < 0.001). Conclusions: The relationship between HT and PTC is still far from clear and represents an unresolved issue. Our own study has underlined the frequent coexistence of these two pathologies, an aspect not to be neglected in clinical practice. Patients receiving HT diagnosis should undergo careful follow-up and, especially those with the nodular variant, should undergo a frequent both clinical and cytological evaluation of the nodular lesions, taking always into great consideration the surgical approach of total thyroidectomy
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