8,267 research outputs found
Nitric oxide and hydrogen sulfide: the gasotransmitter paradigm of the vascular system.
There are several reviews on NO and hydrogen sulfide (H2 S) and their role in vascular diseases in the current relevant literature. The aim of this review is to discuss, within the limits of present knowledge, the interconnection between these two gasotransmitters in vascular function. In particular, the review focuses on the role played by the balance between the NO and H2 S pathways in either physiological or pathological conditions. The distinction between physiology and pathology has been made in order to dissect the molecular basis of this crosstalk, highlighting how and if this balance varies, depending upon the vascular status. Perspectives and possible novel therapeutic approaches are also discussed
A fast feasibility tool for the assessment of fuel switch in the concept design of merchant ships
Due to the utmost importance of international maritime transport within the global economy, shipping contributes substantially to the emission of pollutants and Greenhouse Gases. Consequently, it is called to reduce its environmental impact, in accordance with the regulations that will enter into force in the next years. In this framework, innovative technologies can find fruitful applications in new constructions, but there is still a significant number of operating ships that needs to be technologically updated. Nonetheless, since these ships may be already in the middle of their service life, revamping operations must take into account the purpose of both reducing pollution and avoiding long and expensive interventions. The sustainability-oriented production is one of the most discussed topics and in this paper, the authors aim at describing the potential technologies and solutions to adapt operating ships to the future emission threshold limits. Then, they propose a tool for supporting energy conversion studies on ships. The tool was tested on an Oil Tanker selected as a case study; different layouts exploiting the use of liquefied natural gas, ammonia, and methanol as alternative fuels were analysed. The considered technological solutions were compared on the basis of both technical and economic aspects. Indeed, technological feasibility and economic viability represent the most important discriminants for the diffusion of such innovations on a wide scale and in particular for commercial vessels employed predominantly in long and international voyages
Effectiveness of surgical procedures in the acceleration of orthodontic tooth movement: Findings from systematic reviews and meta-analyses
The current overview aimed to summarise the findings provided by systematic reviews (SRs) on the effect of surgical procedures in the acceleration of tooth movement and to assess the methodological quality of the included SRs. Three electronic databases have been explored. SRs addressing the effects of surgical procedures on the acceleration of tooth movement were included. The methodological quality of the included SRs was assessed using the updated version of “A Measurement Tool to Assess Systematic Review” (AMSTAR-2). Twenty-eight (28) SRs were included. The methodological quality of the included reviews ranged between critically low (6 studies) and high (12 studies). The most common critical weakness in the included reviews was the absence of clearly a-prior established review methods and any significant deviations from the protocol. The most studied surgical procedure was corticotomy, followed by micro-osteoperforation, piezocision and periodontally accelerated osteogenic orthodontics. The majority of the included SRs supported short-term favourable effects of corticotomy on treatment time and tooth movement rate, in the short-term. However, the authors of the included SRs reported that results were based on weak quality evidence. Conflicting results arise from the existent SRs with regards to the effectiveness of piezocision and micro-osteoperforation. Few SRs summarised complications and side effects of surgical techniques, supporting absence of loss of tooth vitality, periodontal problems, or severe root resorption. The current overview of SRs highlighted the need of high quality SRs comparing different surgical approaches for tooth movement acceleration though network meta-analysis, in order to determine the most efficient instrument for orthodontic movement acceleration
Electrification of a large catamaran water bus for everyday commuting in the Venice Lagoon
The continuous problem of environmental degradation caused by exhaust emissions in maritime navigation has prompted the search for sustainable solutions. One potential approach involves the development of innovative, environmentally friendly passenger boats that align with principles of ecological sustainability. The design process for such vessels demands meticulous consideration of the operational context and requirements. In regions with distinctive features like the Venice Lagoon, design alternatives must take into account the area's unique characteristics and comply with existing laws and regulations. This paper proposes a feasibility study on an innovative hybrid-electric catamaran water bus designed to both minimize wave generation and operate in Zero Emission Mode, aiming to properly address the mentioned environmental and navigation challenges
Digital Transformation, Applications, and Vulnerabilities in Maritime and Shipbuilding Ecosystems
The evolution of maritime and shipbuilding supply chains toward digital ecosystems increases operational complexity and needs reliable communication and coordination. As labor and suppliers shift to digital platforms, interconnection, information transparency, and decentralized choices become ubiquitous. In this sense, Industry 4.0 enables "smart digitalization"in these environments. Many applications exist in two distinct but interrelated areas related to shipbuilding design and shipyard operational performance. New digital tools, such as virtual prototypes and augmented reality, begin to be used in the design phases, during the commissioning/quality control activities, and for training workers and crews. An application relates to using Virtual Prototypes and Augmented Reality during all the design and construction phases. Another application relates to the cybersecurity protection of operational networks that support shipbuilding supply chains that ensures the flow of material and labor to the shipyards. This protection requires a holistic approach to evaluate their vulnerability and understand ripple effects. This paper presents the applications of Industry 4.0 for the areas mentioned above. The first case in shipbuilding design is an example of how the virtual prototype of a ship, together with wearable devices enabling augmented reality, can be used for the quality control of the construction of ship systems. For the second case, we propose developing an artificial intelligence-based cybersecurity supply network framework that characterizes and monitors shipbuilding supply networks and determines ripple effects from disruptions caused by cyberattacks. This framework extends a novel risk management framework developed by Diaz and Smith and Smith and Diaz that considers complex tiered networks
Laser Scanning Application for the Enhancement of Quality Assessment in Shipbuilding Industry
The need for a shipyard to improve the quality of its final products is crucial to be competitive in the shipbuilding market. In particular, in the latest years the attention has moved to reducing the presence and occurrence of dimensional non-conformities throughout the entire construction process, in order to facilitate and speed up subsequent phases and ship blocks assembly. This necessity has led shipyards management to evaluate the introduction of dimensional detection systems for the manufactured articles. As an innovative solution, laser scanning technologies have been already tested in extensive ways at industrial level and have recently found application in the shipbuilding sector. Specifically, among the various available technologies, laser scanner systems and laser trackers proved to be the most suitable ones for the targeted purposes. Within the paper, the authors firstly describe the evolution of shipbuilding process and highlight its peculiarities. Then, they focuse on the quality assessment process with a specific reference to both dimensional controls and laser scanning technologies that may support such operation. The application of the latest-generation tools is validated through the presentation and discussion of a real case study related to a ship block. Finally, the authors present the potential future developments and integration of laser scanning technologies within Industry 4.0 framework
Invariance: a Theoretical Approach for Coding Sets of Words Modulo Literal (Anti)Morphisms
Let be a finite or countable alphabet and let be literal
(anti)morphism onto (by definition, such a correspondence is determinated
by a permutation of the alphabet). This paper deals with sets which are
invariant under (-invariant for short).We establish an
extension of the famous defect theorem. Moreover, we prove that for the
so-called thin -invariant codes, maximality and completeness are two
equivalent notions. We prove that a similar property holds in the framework of
some special families of -invariant codes such as prefix (bifix) codes,
codes with a finite deciphering delay, uniformly synchronized codes and
circular codes. For a special class of involutive antimorphisms, we prove that
any regular -invariant code may be embedded into a complete one.Comment: To appear in Acts of WORDS 201
Geoscience studies in the Maltese Islands: a gateway to the Central Mediterranean region
The location of the Maltese Islands, at the centre of the Mediterranean Sea, places them as a reference for regional climatic, tectonic and marine processes that have affected the Mediterranean basin. Our review work targeted the entire geoscientific literature produced about the Maltese Islands, covering the period from the 19th century to 2023. We identified ca. 390 papers, by using the main literature databases, and classified them according to the main scientific fields. Geomorphology, stratigraphy and sedimentology represent the main research topics, followed by palaeontology and structural geology. We analysed the temporal distribution of this scientific production, highlighting an overall increasing trend in the number of papers over time. This reveals a growing interest in the geoscientific research related to the Maltese Islands. The review emphasises collaborative efforts between scientists from different fields, illustrating the interdisciplinary nature of geoscientific research in Malta. Our results show that the scientific collaboration between authors, and affiliated institutions, is also based on the shared history and linguistic ties, among the Maltese, Italian and British cultures. The outputs of our review aim to be a comprehensive reference for those undertaking geoscientific research on the Islands
Effect of orthopedic and functional orthodontic treatment in children with obstructive sleep apnea: A systematic review and meta-analysis
Orthodontic treatment is suggested in growing individuals to correct transverse maxillary deficiency and mandibular retrusion. Since, as a secondary effect, these orthodontic procedures may improve pediatric obstructive sleep apnea (OSA), this systematic review assessed their effects on apnea-hypopnea index (AHI) and oxygen saturation (SaO2). Twenty-five (25) manuscripts were included for qualitative synthesis, 19 were selected for quantitative synthesis. Five interventions were analyzed: rapid maxillary expansion (RME, 15 studies), mandibular advancement (MAA, five studies), myofunctional therapy (MT, four studies), and RME combined with MAA (one study). RME produced a significant AHI reduction and minimum SaO2 increase immediately after active treatment, at six and 12 months from baseline. A significant AHI reduction was also observed six and 12 months after the beginning of MAA treatment. MT showed positive effects, with different protocols. In this systematic review and meta-analysis of data from mainly uncontrolled studies, interceptive orthodontic treatments showed overall favorable effects on respiratory outcomes in pediatric OSA. However, due to the low to very low level of the body evidence, this treatment cannot be suggested as elective for OSA treatment. An orthodontic indication is needed to support this therapy and a careful monitoring is required to ensure positive improvement in OSA parameters
Long-term prediction of adherence to continuous positive air pressure therapy for the treatment of moderate/severe obstructive sleep apnea syndrome
BACKGROUND: Continuous positive airway pressure (CPAP) therapy is a highly effective treatment for obstructive sleep apnea syndrome (OSAS). However, poor adherence is a limiting factor, and a significant proportion of patients are unable to tolerate CPAP. The aim of this study was to determine predictors of long-term non-compliance with CPAP.
METHODS: CPAP treatment was prescribed to all consecutive patients with moderate or severe OSAS (AHI ≥15 events/h) (n = 295) who underwent a full-night CPAP titration study at home between February 1, 2002 and December 1, 2016. Adherence was defined as CPAP use for at least 4 h per night and five days per week. Subjects had periodical follow-up visits including clinical and biochemical evaluation and assessment of adherence to CPAP.
RESULTS: Median follow-up observation was 74.8 (24.2/110.9) months. The percentage of OSAS patients adhering to CPAP was 41.4% (42.3% in males and 37.0% in females), and prevalence was significantly higher in severe OSAS than in moderate (51.8% vs. 22.1%; p < 0.001; respectively). At multivariate analysis, lower severity of OSAS (HR = 0.66; CI 95 0.46-0.94) p < 0.023), cigarette smoking (HR = 1.72; CI 95 1.13-2.61); p = 0.011), and previous cardiovascular events (HR = 1.95; CI 95 1.03-3.70; p = 0.04) were the only independent predictors of long-term non-adherence to CPAP after controlling for age, gender, and metabolic syndrome.
CONCLUSIONS: In our cohort of patients with moderate/severe OSAS who were prescribed CPAP therapy, long-term compliance to treatment was present in less than half of the patients. Adherence was positively associated with OSAS severity and negatively associated with cigarette smoking and previous cardiovascular events at baseline
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