Technological Educational Institute of Athens

Over the last years deep learning methods have been shown to outperform previous state-of-the-art machine learning techniques in several fields, with computer vision being one of the most prominent cases. This review paper provides a brief overview of some of the most significant deep learning schemes used in computer vision problems, that is, Convolutional Neural Networks, Deep Boltzmann Machines and Deep Belief Networks, and Stacked Denoising Autoencoders. A brief account of their history, structure, advantages, and limitations is given, followed by a description of their applications in various computer vision tasks, such as object detection, face recognition, action and activity recognition, and human pose estimation. Finally, a brief overview is given of future directions in designing deep learning schemes for computer vision problems and the challenges involved therein.

The distributed nature and dynamic topology of Wireless Sensor Networks (WSNs) introduces very special requirements in routing protocols that should be met. The most important feature of a routing protocol, in order to be efficient for WSNs, is the energy consumption and the extension of the network's lifetime. During the recent years, many energy efficient routing protocols have been proposed for WSNs. In this paper, energy efficient routing protocols are classified into four main schemes: Network Structure, Communication Model, Topology Based and Reliable Routing. The routing protocols belonging to the first category can be further classified as flat or hierarchical. The routing protocols belonging to the second category can be further classified as Query-based or Coherent and non-coherent-based or Negotiation-based. The routing protocols belonging to the third category can be further classified as Location-based or Mobile Agent-based. The routing protocols belonging to the fourth category can be further classified as QoS-based or Multipath-based. Then, an analytical survey on energy efficient routing protocols for WSNs is provided. In this paper, the classification initially proposed by Al-Karaki, is expanded, in order to enhance all the proposed papers since 2004 and to better describe which issues/operations in each protocol illustrate/enhance the energy-efficiency issues.

Jamming represents the most serious security threat in the field of wireless sensor networks (WSNs), as it can easily put out of order even WSNs that utilize strong highlayer security mechanisms, simply because it is often ignored in the initial WSN design. The objective of this article is to provide a general overview of the critical issue of jamming in WSNs and cover all the relevant work, providing the interested researcher pointers for open research issues in this field. We provide a brief overview of the communication protocols typically used in WSN deployments and highlight the characteristics of contemporary WSNs, that make them susceptible to jamming attacks, along with the various types of jamming which can be exercised against WSNs. Common jamming techniques and an overview of various types of jammers are reviewed and typical countermeasures against jamming are also analyzed. The key ideas of existing security mechanisms against jamming attacks in WSNs are presented and open research issues, with respect to the defense against jamming attacks are highlighted.

In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy, hadrontherapy, molecular radiotherapy, and in vivo dose monitoring. Investigations that have been performed using GEANT4 only are also mentioned to illustrate the potential of GATE. The very practical feature of GATE making it easy to model both a treatment and an imaging acquisition within the same framework is emphasized. The computational times associated with several applications are provided to illustrate the practical feasibility of the simulations using current computing facilities.

Self-reported dietary intake is assessed by methods of real-time recording (food diaries and the duplicate portion method) and methods of recall (dietary histories, food frequency questionnaires, and 24-hour dietary recalls). Being less labor intensive, recall methods are more frequently employed in nutritional epidemiological investigations. However, sources of error, which include the participants' inability to fully and accurately recall their intakes as well as limitations inherent in the food composition databases applied to convert the reported food consumption to energy and nutrient intakes, may limit the validity of the generated information. The use of dietary biomarkers is often recommended to overcome such errors and better capture intra-individual variability in intake; nevertheless, it has its own challenges. To address measurement error associated with dietary questionnaires, large epidemiological investigations often integrate sub-studies for the validation and calibration of the questionnaires and/or administer a combination of different assessment methods (e.g. administration of different questionnaires and assessment of biomarker levels). Recent advances in the omics field could enrich the list of reliable nutrition biomarkers, whereas new approaches employing web-based and smart phone applications could reduce respondent burden and, possibly, reporting bias. Novel technologies are increasingly integrated with traditional methods, but some sources of error still remain. In the analyses, food and nutrient intakes always need to be adjusted for total daily energy intake to account for errors related to reporting.

BACKGROUND: The prevalence of musculoskeletal complaints in dentists is high although relatively few studies had focus in this profession. The aim of this study was to investigate the relations between physical, psychosocial, and individual characteristics and different endpoints of musculoskeletal complaints of low back, neck, shoulders and hand/wrist. METHODS: A questionnaire survey was carried out among 430 dentists (response 88%) in Thessaloniki, Greece. Questions include data on physical and psychosocial workload, need for recovery, perceived general health and (i) the occurrence of musculoskeletal complaints in the past 12 months, (ii) chronic complaints during at least 1 month, complaints which led to (iii) sickness absence, and (iv) medical care seeking. In logistic regression analysis odds ratios were estimated for all relevant risk factors. RESULTS: 62% of dentists reported at least one musculoskeletal complaint, 30% chronic complaints, 16% had spells of absence and, 32% sought medical care. Self-reported factors of physical load were associated with the occurrence of back pain (OR = 1.59), shoulder pain (OR = 2.57) and, hand/wrist pain (OR = 3.46). With the exception of hand/wrist complaints, the physical factors were not associated with chronic complaints and musculoskeletal sickness absence. Physical load showed a trend with the number of musculoskeletal complaints with ORs of 2.50, 3.07 and 4.40 for two, three and four musculoskeletal complaints, respectively. No consistent influence of psychosocial factors on complaints, chronicity, sickness absence and medical care seeking was observed. A perceived moderate general health was a significant factor for chronic complaints, comorbidity and medical care seeking where high perceived exertion was significant for absenteeism. Living alone was also related with increased absenteeism due to shoulder pain (OR = 5.01) and hand/wrist (OR = 4.07). CONCLUSIONS: The physical load among dentists seems to put them at risk for the occurrence of musculoskeletal disorders. More than one and severe complaints are related to perceived general health while high perceived exertion and social characteristics are associated with sickness absence. Chronic symptoms seem to determine medical care seeking. Ergonomic interventions may have a greater impact in prevention of hand/wrist complaints. When investigating the influence of work-related risk factors on musculoskeletal health, psychosocial and other personal characteristics should be taken into account.

Introduction: Having breast cancer or receiving treatment has been seen as a traumatic experience for women due to its impacts on their self-image and sexual relationship, and may lead to an psychological reactions such as denial, anger, or intense fear toward their disease and treatment process. Also many of breast cancer patients have psychiatric morbidities such as depression and anxiety. Purpose: The purpose of this study was to assess the prevalence and associated factors of depression and anxiety in breast cancer patients, in order to identify independent predictors of mental health disorders risk. Material and Methods: A cohort of 152 breast cancer patients who were attending an outpatient oncology department was recruited. Data were collected with a structured questionnaire consisted by social, clinical and demographic information and PHQ-2 and GAD-2 scales. Results: The mean age of the patients was 53.25 years (SD=12.10), 69.7% of the patients underwent mastectomy and 30.3% ongectomy. Chemotherapy received 46.1% of patients as adjuvant therapy, 15.8% radiotherapy and 38.2% received both chemotherapy and radiotherapy. A large percentage found to be classified as depressed (38.2%) and anxious (32.2%) and factors that found to be associated were age, marital status, educational level, stage of cancer from univariate analyses and place of residence, religion, symptoms burden from multivariate analysis (for depression and anxiety). Conclusions: Breast cancer patients are in high risk for developing psychiatric disorders such as depression and anxiety. Being rural resident, non-Orthodox Christian and experiencing extend symptom burden can be predicting factors associated with depression and anxiety in breast cancer patients.

BACKGROUND: Platelet indices are potentially useful markers for the early diagnosis of thromboembolic diseases. An increase in both mean platelet volume (MPV) and platelet distribution width (PDW) due to platelet activation, resulting from platelet swelling and pseudopodia formation was hypothesized. METHODS: Platelet indices (MPV and PDW) in three groups of persons, using impedance and optical technology were measured. The first group consisted of patients with established platelet activation and healthy control subjects. The second study group included pregnant women in different trimesters of pregnancy. The effect of storage time on MPV and PDW in blood samples of a third group of randomly chosen patients was also assessed. RESULTS: There was a significant increase in MPV (P<0.001) and PDW (P<0.001) in patients with confirmed platelet activation compared to healthy control subjects. Only PDW showed a significant increase from the first to the third trimester of pregnancy (P=0.009). Temporal changes of MPV and PDW over storage time revealed a significant increase in MPV (P<0.001), in contrast to a significant decrease in PDW (P<0.05). CONCLUSION: MPV and PDW are simple platelet indices, which increase during platelet activation. PDW is a more specific marker of platelet activation, since it does not increase during simple platelet swelling.

OBJECTIVES: To identify the intrinsic risk factors of non-contact strains in the hamstrings and quadriceps muscles of professional soccer players via a cohort prospective design. METHODS: A total of 100 professional soccer players (aged 19.4-27.8 years) from four professional teams underwent a composite musculoskeletal assessment at preseason. Intrinsic risk factors included dichotomies of asymmetries in muscle strength, flexibility, proprioception, anthropometry and knee joint stability, and of previous injuries. Muscle strains were prospectively monitored during the subsequent season using questionnaires. The data were analysed via binary logistic regression. RESULTS: Thirty-eight percent of the players sustained one or more lower-extremity muscle strains. Sixteen (42.1 %) and seven (18.4 %) of them were clinically diagnosed as having non-contact muscle strains at their hamstrings and quadriceps, respectively. Players with eccentric hamstring strength asymmetries (OR=3.88; 95% CI 1.13 to 13.23), functional leg length asymmetries (OR=3.80; 95% CI 1.08 to 13.33) and no previous hamstrings injuries (OR=0.15; 95% CI 0.029 to 0.79) were at greater risk of sustaining a hamstring muscle strain. Players with eccentric strength (OR=5.01; 95% CI 0.92 to 27.14) and flexibility asymmetries (OR=4.98; 95% CI 0.78 to 31.80) in their quadriceps as well as heavier (OR=10.70; 95% CI 0.73 to 156.37) and shorter players (OR=0.08; 95% CI 0.00 to 1.35) were at greater risk of sustaining a strain in this muscle group. CONCLUSIONS: Professional soccer players with functional asymmetries possess a higher risk of sustaining hamstring strains. Previous injury seems not to constitute a risk factor. The systematic isokinetic evaluation of the lower extremities during the preseason period can provide therapists and trainers with valuable data regarding the predictive elements of non-contact hamstring strains in professional soccer players.

INTRODUCTION: The short International Physical Activity Questionnaire (IPAQ-short) has frequently been used for national and international comparable physical activity (PA) prevalence studies. The purpose of this paper is to describe a Greek version of IPAQ-short (IPAQ-Gr) and present its reliability properties in Greek young and healthy adults. METHODS: Two hundred and eighteen health science students of the Athens Technological Educational Institute, aged 19-29 years, were randomly selected and participated in the study. An intra-examiner reliability study over time (8 and 30 days apart) was carried out to assess IPAQ-Gr repeatability. An inter-examiner reliability study was also performed to assess the consistency of IPAQ-Gr outcomes between examiners. At the same time, an intra-examiner reliability study using an independent sample of 175 medical students at the University of Ioannina was carried out in order to examine multi-centre IPAQ-Gr reliability. Intra-class correlation coefficients for IPAQ scores and kappa statistics and percent agreement for physical activity classification were used in the analysis. RESULTS: Intra-class correlation coefficients (ICCs) between day-1 and day-9 assessments for IPAQ total and vigorous PA were high in all groups examined (0.84 to 0.93). ICCs for walking PA, moderate PA and sitting hours were lower, but still good (0.69 to 0.81). Repeatability of IPAQ-Gr outcomes after one-month re-administration was high for total and vigorous PA (0.87, 0.81) and good for moderate (0.66) and walking PA (0.75). Inter-examiner reliability data showed that all correlations between examiners were greater than 0.70, up to 0.87 (paired t-test, p=NS), with the exception of moderate PA, where correlations were weaker (0.58 to 0.64). Similar results were found when intra-examiner correlations were compared between educational institutes (multi-centre inter-examiner reliability of IPAQ). CONCLUSIONS: IPAQ-Gr was found to present acceptable reliability properties in Greek young adults. IPAQ-Gr showed high repeatability values for total and vigorous PA, and good for moderate and walking PA.

The fundamental role of copper and the recognition of its complexes as important bioactive compounds in vitro and in vivo aroused an ever-increasing interest in these agents as potential drugs for therapeutic intervention in various diseases. The vast array of information available for their bioinorganic properties and mode of action in several biological systems, combined with the new opportunities offered by the flourishing technologies of medicinal chemistry, is creating an exciting scenario for the development of a novel generation of highly active drugs with minimized side effects which could add significantly to the current clinical research and practice. In this paper we attempt to summarize all the available-to-date information on these issues.

Red blood cell (RBC) aging in the blood bank is characterized by the accumulation of a significant number of biochemical and morphologic alterations. Recent mass spectrometry and electron microscopy studies have provided novel insights into the molecular changes underpinning the accumulation of storage lesions to RBCs in the blood bank. Biochemical lesions include altered cation homeostasis, reprogrammed energy, and redox metabolism, which result in the impairment of enzymatic activity and progressive depletion of high-energy phosphate compounds. These factors contribute to the progressive accumulation of oxidative stress, which in turn promotes oxidative lesions to proteins (carbonylation, fragmentation, hemoglobin glycation) and lipids (peroxidation). Biochemical lesions negatively affect RBC morphology, which is marked by progressive membrane blebbing and vesiculation. These storage lesions contribute to the altered physiology of long-stored RBCs and promote the rapid clearance of up to one-fourth of long-stored RBCs from the recipient's bloodstream after 24 hours from administration. While prospective clinical evidence is accumulating, from the present review it emerges that biochemical, morphologic, and omics profiles of stored RBCs have observable changes after approximately 14 days of storage. Future studies will assess whether these in vitro observations might have clinically meaningful effects.

In a companion paper, a new finite element technique for the analysis of brickwork infilled plane frames under lateral loads has been presented. In the present paper, the influence of the masonry infill panel opening in the reduction of the infilled frames stiffness has been investigated by means of this technique. A parametric study has been carried out using as parameters the position and the percentage of the masonry infill panel opening for the case of one-story one-bay infilled frame. The investigation has been extended to the case of multistory, fully or partially infilled frames. In particular, the redistribution of action effects of infilled frames under lateral loads has been studied. It is shown that the redistribution of shear force is critically influenced by the presence and continuity of infill panels. The presence of infills leads, in general, to decreased shear forces on the frame columns. However, in the case of an infilled frame with a soft ground story, the shear forces acting on columns are considerably higher than those obtained from the analysis of the bare frame.

This article summarizes recent work in optimal experimental design in nonlinear problems, in which the major difficulty in obtaining good or optimal designs is their dependence on the true value of the parameters. This difficulty arises in problems with nonlinear models or with linear models in which interest lies in a nonlinear function of the parameters. Most approaches use a static design based on “prior” information about the parameters or a sequential procedure that takes advantage of the inflow of new information about them. The various versions of these methods are discussed, as are some of the consequent problems of inference. Some selected procedures are compared using simulation studies.

Abstract Gilthead sea bream (Sparus aurata) were stored in melting ice (0 °C) for a period of 24 days from the time of harvest with sensory assessments of the whole raw fish and of the cooked fish flesh conducted at regular intervals. The ungutted fish was given an EC freshness grade E for up to 3 days, grade A for a further 7 days, and grade B for 4 more days after which it was graded as C (unfit). The sensory score for flavour of the cooked fillets decreased linearly with period of storage: fresh characteristic flavours were present for 2–4 days, decreasing to a relatively bland flavour after 10–12 days. Off flavours were evident by 13–15 days storage and by 18–19 days the flesh was unpalatable. With the possible exception of hypoxanthine, none of the chemicals investigated was particularly useful as an indicator of change. Changes in pH, trimethylamine and total volatile bases during the first half of the edible storage life were insignificant. Deterioration of flesh lipids, assessed by free fatty acid content and thiobarbituric acid value, appeared to present no serious problem during shelf-life. Proximate composition and sensory attributes, appropriate for routine inspection of gilthead sea bream were also determined.

Kicking and cutting skills in soccer are clearly unilateral, require asymmetrical motor patterns and lead to the development of asymmetrical adaptations in the musculoskeletal function of the lower limbs. Assuming that these adaptations constitute a chronicity-dependent process, this study examined the effects of professional training age (PTA) on the composite strength profile of the knee and ankle joint in soccer players. One hundred soccer players (n=100) with short (5-7 years), intermediate (8-10 years) and long (>11 years) PTA were tested bilaterally for isokinetic concentric and eccentric strength of the knee and ankle muscles. Knee flexion-extension was tested concentrically at 60°, 180° and 300 °/sec and eccentrically at 60° and 180 °/sec. Ankle dorsal and plantar flexions were tested at 60 °/sec for both the concentric and eccentric mode of action. Bilaterally averaged muscle strength [(R+L)/2] increased significantly from short training age to intermediate and stabilized afterwards. These strength adaptations were mainly observed at the concentric function of knee extensors at 60°/sec (p = 0. 023), knee flexors at 60°/sec (p = 0.042) and 180°/sec (p = 0.036), and ankle plantar flexors at 60o/sec (p = 0.044). A linear trend of increase in isokinetic strength with PTA level was observed for the eccentric strength of knee flexors at 60°/sec (p = 0.02) and 180°/sec (p = 0.03). Directional (R/L) asymmetries decreased with PTA, with this being mainly expressed in the concentric function of knee flexors at 180°/sec (p = 0.04) and at 300 °/sec (p = 0.03). These findings confirm the hypothesis of asymmetry in the strength adaptations that take place at the knee and ankle joint of soccer players mainly along with short and intermediate PTA. Players with a longer PTA seem to adopt a more balanced use of their lower extremities to cope with previously developed musculoskeletal asymmetries and possibly reduce injury risk. This has certain implications regarding proper training and injury prevention in relation to professional experience in soccer. Key pointsMuscle strength increased from the low (5-7 years) to the intermediate professional training age (8-10 years) and stabilized thereafter.Soccer practicing and competition at the professional level induces critical strength adaptations (asymmetries) regarding the function of the knee and ankle musculature.Soccer players with long professional training age showed a tendency for lower isokinetic strength asymmetries than players with intermediate and short professional training age.

The main objective of this study was the screening of some selected aromatic plants very popular in Greece, with respect to their total phenolic content, antioxidant capacity, reducing activity, and oxidative stability. All plants were extracted with the conventional method, reflux with methanol. The essential oils of the plants were also analyzed for their antioxidant properties. The total phenolic content was determined by the Folin-Ciocalteu method using gallic acid as the standard, while the phenolic substances were identified and quantified by High Performance Liquid Chromatography (HPLC) coupled with a multi-wavelength ultraviolet-visible (UV-vis) detector. The antioxidant capacity of the plant extracts was measured by their ability to scavenge free radicals such as (a) DPPH (2,2-diphenyl-1-picrylhydrazyl) and, (b) ABTS (2,2'-azinobis-(3-ethylbenzothiaziline-6- sulfonate). The Folin-Ciocalteu method proved the existence of antioxidants in the aromatic plant extracts. Taking into account the results of the DPPH and ABTS methods, the free radical scavenging capacity was confirmed. Eventually, all plants exhibited low but noticeable protection levels against lipid oxidation, as determined by the Rancimat test.

Tobacco smoking is a known cause of gastric cancer, but several aspects of the association remain imprecisely quantified. We examined the relation between cigarette smoking and the risk of gastric cancer using a uniquely large dataset of 23 epidemiological studies within the 'Stomach cancer Pooling (StoP) Project', including 10 290 cases and 26 145 controls. We estimated summary odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) by pooling study-specific ORs using random-effects models. Compared with never smokers, the ORs were 1.20 (95% CI: 1.09-1.32) for ever, 1.12 (95% CI: 0.99-1.27) for former, and 1.25 (95% CI: 1.11-1.40) for current cigarette smokers. Among current smokers, the risk increased with number of cigarettes per day to reach an OR of 1.32 (95% CI: 1.10-1.58) for smokers of more than 20 cigarettes per day. The risk increased with duration of smoking, to reach an OR of 1.33 (95% CI: 1.14-1.54) for more than 40 years of smoking and decreased with increasing time since stopping cigarette smoking (P for trend<0.01) and became similar to that of never smokers 10 years after stopping. Risks were somewhat higher for cardia than noncardia gastric cancer. Risks were similar when considering only studies with information on Helicobacter pylori infection and comparing all cases to H. pylori+ controls only. This study provides the most precise estimate of the detrimental effect of cigarette smoking on the risk of gastric cancer on the basis of individual data, including the relationship with dose and duration, and the decrease in risk following stopping smoking.

The oil from Moringa oleifera variety Mbololo seeds from Kenya was extracted using three different procedures including cold press (CP), extraction with n-hexane (H), and extraction with a mixture of chloroform/methanol (50:50) (CM). The oil concentration ranged from 25.8% (CP) to 31.2% (CM). The density, refractive index, color, smoke point, viscosity, acidity, saponification value, iodine value, fatty acid methyl esters, sterols, tocopherols (by HPLC), peroxide value, and at 232 and 270 nm and the susceptibility to oxidation measured with the Rancimat method were determined. The oil was found to contain high levels of unsaturated fatty acids, especially oleic (up to 75.39%). The dominant saturated acids were behenic (up to 6. 73%) and palmitic (up to 6.04%). The oil was also found to contain high levels of beta-sitosterol (up to 50.07%), stigmasterol (up to 17.27%), and campesterol (up to 15.13%). alpha-, gamma-, and delta-tocopherols were detected up to levels of 105.0, 39.54, and 77. 60 mg/kg of oil, respectively. The induction period (at 120 degrees C) of M. oleifera seed oil was reduced from 44.6 to 64.3% after degumming. The M. oleifera seed oil showed high stability to oxidative rancidity. The results of all the above determinations were compared with those of a commercial virgin olive oil.

The wide utilization of Wireless Sensor Networks (WSNs) is obstructed by the severely limited energy constraints of the individual sensor nodes. This is the reason why a large part of the research in WSNs focuses on the development of energy efficient routing protocols. In this paper, a new protocol called Equalized Cluster Head Election Routing Protocol (ECHERP), which pursues energy conservation through balanced clustering, is proposed. ECHERP models the network as a linear system and, using the Gaussian elimination algorithm, calculates the combinations of nodes that can be chosen as cluster heads in order to extend the network lifetime. The performance evaluation of ECHERP is carried out through simulation tests, which evince the effectiveness of this protocol in terms of network energy efficiency when compared against other well-known protocols.