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Introduction: Despite the significant progress that has been made during the last decade, Greece still faces the effects of road traffic accidents (RTAs) to a great extent every year. This study represents an epidemiological approach to road traffic injuries (RTIs) presenting to a secondary hospital in a geographical area with very low-quality road network; it aims to indicate possible preventive measures and actions. Methods: The present study was conducted in Rethymnon General Hospital between January 2018 and February 2020. Data from all trauma patients who presented to the emergency department (ED) after RTAs were retrospectively collected from patient medical records. The severity of injury sustained by road traffic victims was graded using the Injury Severity Score (ISS). Results: During the study period, 1582 trauma patients presented to the ED after RTAs. There were 1079 men and 503 women and the median age was 30 years. In total, 818 motorcycle-related injuries (51.7%), 497 automobile-related injuries (31.4%), 165 bicycle-related injuries (10.4%) and 102 pedestrian injuries (6.4%) were documented. Of the 1582 trauma patients, 58.2% (921) presented with injuries to the extremities, 35.3% (554) presented with thoracic injuries, 34.4% (541) presented with head injuries, 30% (475) presented with spinal column injuries, 17.4% (271) presented with facial injuries, 12.9% (203) presented with abdominal injuries and 10.3% (162) presented with pelvic injuries. A significant increase in the number of incidents was noticed during the tourist season. Median ISS was 2 (IQR=4). 53.7% of patients who were transferred to the hospital by ambulance had an ISS≤4. In 41 cases, transportation to a tertiary hospital was necessary, six patients had emergency operations and 13 others died in the ED. The median length of hospital stay was 3 (IQR=6) days. Conclusion: Actions that could possibly mitigate the burden of RTIs in the district of Rethymnon include upgrading the level of law enforcement, implementing educational strategies and information campaigns against inappropriate ambulance use, encouraging facilities to develop trauma registries and ensuring adequate hospital staffing.

The purpose of this study is to determine the effect of various commonly used antiglaucoma eye drops on inflammatory mediators such as the platelet activating factor (PAF).Various intraocular pressure (IOP) lowering drops were tested to examine their inhibitory effect on PAF. Multiple eye drops were tested in washed rabbit platelets (WRPs) in order to determine the interaction between these eye drops and the inhibition of PAF in the PAF-induced platelet aggregation model. In addition, we examined the eyedrops' effect on PAF-metabolism, through in vitro analysis on PAF basic metabolic enzymes (PAF-CPT, lyso PAF-AT, and PAF-AH).Latanoprost (Xalatan) was found to be the most potent in inhibiting PAF, suggesting that it is the most effective in decreasing IOP amongst the eye drops tested. Conversely, dorzolamide hydrochloride-timolol (Cosopt) exhibited the least anti-PAF action.This is the first study examine the relationship between PAF activity and glaucoma medication. Potency in PAF inhibition may be related to drop efficacy.

Antiretroviral therapy (ΑRT) has successfully decreased AIDS morbidity and mortality and increased the lifespan of HIV patients to several decades. However, numerous factors contribute with unknown mechanisms to chronic immune activation and inflammation leading to severe “non-AIDS morbidities’’. Platelet Activating Factor (PAF) is a potent lipid inflammatory mediator with important role in the ‘’non-AIDS morbidities’’. The purpose of this study was to investigate whether tenofovir-DF/emtricitabine and abacavir/lamivudine with atazanavir boosted ritonavir (ART_A and ART_B, respectively) affect in vitro PAF activity and in vivo PAF levels and metabolism. In this intent, the two ART regimens were examined in vitro against platelet aggregation induced by PAF. In addition, PAF levels and PAF metabolic enzymes were determined in HIV-1 infected volunteers before and after the initiation of antiretroviral therapy for a 12-month period. The in vitro results showed that ritonavir was the most potent inhibitor against PAF induced platelet aggregation while abacavir presented the less potent action. The in vivo results showed that tenofovir-DF/emtricitabine with atazanavir-r seems not to affect PAF levels and metabolism while abacavir/lamivudine with atazanavir-r increased bound and total PAF blood levels, PAF biosynthesis in platelets and also decreased Lp-PLA2 activity. In addition, ART_B revealed higher lyso-PAF-AT specific activity at 3rd, 6th and 9th month (p3=0.04, p6=0.04 and p9=0.03) compared to ART_A. In conclusion, there is a direct relation between in vitro and in vivo effect of antiretrovirals on PAF and abacavircontaining regimen activates PAF biosynthesis leading to elevated PAF levels.

Platelet Activating factor (PAF) is a potent inflammatory mediator that is involved in the initiation and the prolongation of atherosclerosis. The purpose of the study was to investigate the effect of wine consumption on the activity of PAF metabolic enzymes and on IL-6 levels as a cytokine inflammatory marker. Healthy men participated in 4 daily trials and consumed a standardized meal along with Robola wine (trial R), or Cabernet Sauvignon (trial CS), or ethanol solution (trial E), or water (trial W). A significant trial effect was found in the activity of lyso-PAF acetyltransferase (Lyso-PAF AT) (ptrial=0.01). In specific, R trial decreased enzyme activity compared to E trial (p=0.03) while a trend for differentiation was observed between CS trial and E one (p=0.06) as well as between R trial and W one (p=0.07). Concerning PAF-cholinephosphotransferase (PAF-CPT) activity, a significant trial effect was found (ptrial

Opportunistic spectrum access is a key technology for the development of novel applications with stringent QoS requirements on top of wireless sensor networks. However, the many challenges posed by opportunistic spectrum access itself are further exacerbated by the power constrained nature of wireless sensors and the QoS requirements of the applications to be supported. In this work we consider the problem of dynamic spectrum assignment in the context of cognitive CSMA/CA based wireless sensor networks. We propose a two-stage dynamic spectrum assignment scheme that exhibits minimal power consumption and guarantees the QoS requirements of data flows in the network. The proposed scheme utilizes both opportunistic and free access bands via cognitive radio technology and is based on a two-stage stochastic integer program with recourse. Numerical results verify the effectiveness of the proposed dynamic spectrum assignment scheme.

Platelet-activating factor (PAF), a mediator of proatherosclerotic inflammatory processes, is also implicated in endothelial dysfunction during human immunodeficiency virus (HIV) infection. We examined PAF metabolism in blood of naive male patients, 8 with early HIV infection (group A) and 17 just before treatment initiation (group B), versus 18 healthy age-matched males (group C). Statistical analysis was performed with 1-way analysis of variance (ANOVA) criterion and Pearson r test. Higher PAF biosynthesis in patients’ leukocytes versus group C was accompanied by an increase in lipoprotein-associated phospholipase A2 (Lp-PLA2) activity that degrades PAF. Moreover, PAF synthesis was higher and Lp-PLA2 activity was lower in group B compared to group A. Lipoprotein-associated phospholipase A2 was positively correlated with viral load and negatively correlated with CD4 cell counts in group B. The activities of PAF-basic biosynthetic enzymes in patients’ leukocytes were also negatively correlated with CD4 cell counts. The observed continuous increase in PAF biosynthesis during HIV infection progress seems to amplify the risk of AIDS manifestations and/or cardiovascular complications in HIV-infected patients, while a subsequent increase in Lp-PLA2 activity seems to be a host response.

The Internet-of-things facilitates the development of many groundbreaking applications. A large number of these applications involve mobile end nodes and a sparsely deployed network of base stations that operate as gateways to the Internet. Most of the mobile nodes, at least within city areas, are connected through low power wide area networking technologies (LPWAN) using public frequencies. Mobility and sparse network coverage result in long delays and intermittent connectivity for the end nodes. Disruption Tolerant Networks and utilization of heterogeneous wireless interfaces have emerged as key technologies to tackle the problem at hand. The first technology renders communication resilient to intermittent connectivity by storing and carrying data while the later increases the communication opportunities of the end nodes and at the same time reduces energy consumption whenever short-range communication is possible. However, one has to consider that end nodes are typically both memory and energy constrained devices which makes finding an energy efficient data transmission policy for heterogeneous disruption tolerant networks imperative. In this work we utilize information related to the spatial availability of network resources and localization information to formulate the problem at hand as a dynamic programming problem. Next, we utilize the framework of Markov Decision Processes to derive approximately optimal and suboptimal data transmission policies. We also prove that we can achieve improved packet transmission policies and reduce energy consumption, extending battery lifetime. This is achieved by knowing the spatial availability of heterogeneous network resources combined with the mobile node’s location information. Numerical resultsshow significant gains achieved by utilizing the derived approximately optimal and suboptimal policies.

The present paper aims at presenting an innovative approach to educating teacher-candidates through the art. More specifically, it aims at exploring the benefits of this approach for student-teachers and for their future teaching of social science subjects. It is an experiential approach, based on a multi-level methodology, developed and implemented through the collaboration of the Teacher Education Program of Athens University of Economics and Business with the Aalto University and the Athens School of Fine Arts. After the completion of the implementation of the specific teaching method, the student-teachers have been interviewed, in order to detect their views on the effectiveness of this method, which has been introduced for the first time in the Teacher Education field in Greece. The results are positive with the interviewees reporting having achieved an in-depth and multi-perspective understanding of the matter in discussion as well as enhanced collaborative skills among other benefits.

Olive oil protects against atherosclerosis because of biologically active microconstituents. In this study, total polar lipids from olive oil, pomace, pomace oil and waste byproducts were extracted, fractionated by thin layer chromatography and tested for their bioactivity. The most active ones were further purified on high-performance liquid chromatography, and the resulting lipid fractions were tested for their bioactivity. Bioactive compounds were determined in all samples with the exception of olive pomace oil. These lipids inhibited platelet-activating factor (PAF)-induced platelet aggregation and also induced platelet aggregation. The bioactive compound from olive pomace has been chemically characterized as a glycerylether-sn-2-acetyl glycolipid based on mass spectra. Chemical determinations and mass spectrometry data reinforce the assumption that these active microconstituents share both similar bioactivity and common structural features. The existence of PAF antagonists in polar lipid extracts from olive oil waste by-products render them biologically valuable materials for the food industry that could be used for the production of functional foods. PRACTICAL APPLICATIONS Isolated bioactive polar lipids from waste by-products of the olive oil industry that act as inhibitors of platelet-activating factor (PAF) may be used for enrichment and production of foods with higher nutritional value, as PAF plays a major role in inflammatory disorders, including atherosclerosis development.

Novel applications running on top of wireless sensor networks set new QoS requirements, demand devices' seamless connectivity, and call for new communication paradigms such as opportunistic spectrum access. However, realization of opportunistic spectrum access without causing interference to primary users poses significant challenges that are further exacerbated by the power constrained nature of wireless sensors and the QoS requirements of the supported applications. In this work we consider the problem of dynamic spectrum assignment in opportunistic access spectrum bands in the context of cognitive wireless sensor networks. We propose a dynamic spectrum assignment scheme that establishes a virtual link, between wireless sensors, which exhibits minimal power consumption and deterministic capacity. The virtual link is created on top of opportunistic and free access bands and to this end we utilize cognitive radio technology. The proposed DSA scheme is based on a two-stage stochastic integer program with non-fixed recourse. Numerical results verify the effectiveness of the proposed dynamic spectrum assignment scheme.

We consider the problem of intelligent spectrum sensing based on historical data in the context of Cognitive Wireless Sensor Networks with the goal to minimize the long term energy consumed for spectrum sensing. The problem involves a wireless sensor with cognitive abilities that must decide how often to sense a specific region of the spectrum based on the last known state of its primary user. We model the problem at hand as a pure-exploration multi-armed bandit problem with dependent arms and use two well known arm pulling strategies to tackle it. Next, we identify the existing correlation structure among the candidate solutions and utilize it to significantly speed up the learning process. Numerical results verify the effectiveness of the proposed strategies.

We define a utility-based framework for joint channel assignment and topology control in multi-rate multi-radio wireless mesh networks, and present a greedy algorithm for solving the corresponding optimization problem. The proposed approach can support different target objectives, which are expressed as utility functions of the end-to-end throughput from the gateways to the mesh nodes. The latter accounts for the 802.11 MAC sharing model and rate diversity. The model can be extended to the case of multipath routing, where there are multiple paths from the same or different gateways to the mesh nodes, and for performing joint channel assignment, topology control, and routing.

We define a utility-based framework for joint channel assignment and topology control in multi-rate multi-radio wireless mesh networks, and present a greedy algorithm for solving the corresponding optimization problem. Key features of the proposed approach are the support for different target objectives, which are expressed as utility functions of the MAC layer throughput, and the efficient utilization of wired network gateways, while guaranteeing that for every mesh node there exists a path to a gateway. Investigations show the influence of different target objectives on the channel assignment and network topology, demonstrate the proposed approach's load balancing properties in mesh networks containing multiple gateways, show the effect of 802.11a adjacent channel interference on the channel assignment, and compare the performance of the proposed procedure with a rate-based channel assignment scheme.

We investigate the optimal selection of minimum contention window values to achieve proportional fairness in a multirate IEEE 802.11e test-bed. Unlike other approaches, the proposed model accounts for the contention-based nature of 802.11's MAC layer operation and considers the case where stations can have different weights corresponding to different throughput classes. Our test-bed evaluation considers both the long-term throughput achieved by wireless stations and the short-term fairness. When all stations have the same transmission rate, optimality is achieved when a station's throughput is proportional to its weight factor, and the optimal minimum contention windows also maximize the aggregate throughput. When stations have different transmission rates, the optimal minimum contention window for high rate stations is smaller than for low rate stations. Furthermore, we compare proportional fairness with time-based fairness, which can be achieved by adjusting packet sizes so that low and high rate stations have equal successful transmission times, or by adjusting the transmission opportunity (TXOP)limit so that high rate stations transmit multiple back-to-back packets and thus occupy the channel for the same time as low rate stations that transmit a single packet. The test-bed experiments show that when stations have different transmission rates and the same weight, proportional fairness achieves higher performance than the time-based fairness approaches, in terms of both aggregate utility and throughput.

In this paper we address the issue of service differentiation in wireless networks based on the IEEE 802.11 standard. Wireless local area networks (WLANs) of this type are becoming increasingly prevalent, counting millions of deployed networks in homes, offices and hot spots. However, the medium access control (MAC) protocol and the unpredictability of the wireless channel prohibit the direct employment of classical wireline service differentiation algorithms. The main contribution of this paper is a network layer mechanism, capable of differentiating service, while improving fairness and aggregate throughput in the presence of both uplink (TCP) and downlink traffic. We exploit a class based weight fair queuing (CBWFQ) scheme, properly supplemented by two algorithms that perform periodical weight adjustments. The two algorithms deal effectively with important WLANs problems, such as, unfairness due to location dependent channel errors, uplink-downlink unfairness and decreased throughput for all nodes, when a station transmits at a small rate. The proposed solution has been implemented in a testbed and the conducted experiments confirmed its resultfulness in real life scenarios

In this paper we present the design, implementation, and experience in using network layer mechanisms for service differentiation in 802.11 wireless LANs (WLANs). In particular, we use the class-based weighted fair queuing (CBWFQ) mechanism with weights that are dynamically adjusted based on the achieved throughput of the wireless stations and their physical layer transmission rate. The scheme was implemented in a Linux-based testbed, and experiments show that it can effectively support throughput differentiation, and deal with important WLANs problems, such as unfairness due to location-dependent channel errors, uplink-downlink unfairness, and performance degradation for the whole WLAN when a station transmits at a small rate. The experiments involved best-effort traffic, as well as streaming video and voice-over-IP

Purpose of the study PAF, a potent inflammatory mediator, seems to play a role in the pathogenesis of several AIDS manifestations. PAFantagonists have been studied in this context with promising results. We have previously described the in vitro interaction between HAART and PAF-induced platelet aggregation, as well as between HAART and the specific activities of the basic PAF metabolic enzymes.

Background: Persistent immune activation and inflammation are lying behind HIV-infection even in the setting of ART mediated viral suppression. The purpose of this study is to define the in vivo effect of two first-line ART regimens on certain inflammatory mediators in male HIV patients. Methods: Male, naive, HIV-infected volunteers were assigned either to tenofovir-DF/emtricitabine/efavirenz (Group_T) or abacavir/lamivudine/efavirenz (Group_A). Platelet Activating Factor (PAF) levels and metabolic enzymes together with HIV-implicated cytokines (IL-1beta, IL-6, IL-8, IL-10, IL-12p70, TNFa) and VEGF were determined for a 12-month period. Differences within each group were determined by non-parametric Friedman and Wilcoxon test, while the differences between the groups were checked by ANOVA repeated measures. Results: Both ART regimens present pronounced effect on inflammatory mediators, resulting in decreased PAF levels and Lipoprotein-associated phospholipase A2 (Lp-PLA2) activity for tenofovir-containing regimen and same as baseline PAF levels with a peak though at the 3 rd month as well as elevated Lp-PLA2 activity for abacavir-containing regimen. Conclusions: Studies regarding the effect of first-line ART regimens on inflammation may be beneficial in preventing chronic morbidities during HIV-treatment. From this point of view, the present study suggests an anti-inflammatory effect of tenofovir-containing ART, while the temporary increase of PAF levels in abacavir-containing ART may be the link between the reported cardiovascular risk and abacavir administration.