Associations between sleep complaints, suicidal ideation and depressive symptoms among adolescents and young adults in Greece.

Depression prevalence increases significantly during adolescence/early adulthood. Depression in youth may present suicidal ideation, while suicide represents the leading cause of death in this age group. Moreover, adolescents/young adults frequently report sleep complaints that may partially be due to depressive symptoms. Studies on the associations between depression, sleep complaints and suicidality in this age group are limited. We aimed to examine associations between depressive symptoms, sleep complaints and suicidal ideation in a large (n = 2771), representative sample of adolescents (age: 15-17 years, n = 512) and young adults (age: 18-24 years, n = 2259) from the general population in Greece. A telephone structured questionnaire was administered. Depressive symptoms were assessed using the modified Patient Health-7 questionnaire score, while presence of suicidal ideation and sleep complaints were assessed using the ninth and third question of Patient Health-9 questionnaire, respectively. Mediation logistic regression analysis revealed significant direct paths from depressive symptoms to sleep complaints (odds ratio [OR] 1.22, 95% confidence interval [CI] 1.19-1.24; OR 1.21, 95% CI 1.18-1.24) and suicidal ideation (OR 1.18, 95% CI 1.14-1.22; OR 1.18, 95% CI 1.14-1.22), as well as sleep complaints and suicidal ideation (OR 1.82, 95% CI 1.32-2.50; OR 1.91, 95% CI 1.33-2.76) in the total group and in young adults, respectively, but not among adolescents. Moreover, we detected a significant indirect effect of depressive symptoms on suicidal ideation mediated by sleep complaints (18.8%) in young adults. These findings support the hypothesis that treatment of sleep disturbances among youth with depression may independently further reduce suicidal risk.

Α 10-gigawatt attosecond source for non-linear XUV optics and XUV-pump-XUV-probe studies.

The quantum mechanical motion of electrons and nuclei in systems spatially confined to the molecular dimensions occurs on the sub-femtosecond to the femtosecond timescales respectively. Consequently, the study of ultrafast electronic and, in specific cases, nuclear dynamics requires the availability of light pulses with attosecond (asec) duration and of sufficient intensity to induce two-photon processes, essential for probing the intrinsic system dynamics. The majority of atoms, molecules and solids absorb in the extreme-ultraviolet (XUV) spectral region, in which the synthesis of the required attosecond pulses is feasible. Therefore, the XUV spectral region optimally serves the study of such ultrafast phenomena. Here, we present a detailed review of the first 10-GW class XUV attosecond source based on laser driven high harmonic generation in rare gases. The pulse energy of this source largely exceeds other laser driven attosecond sources and is comparable to the pulse energy of femtosecond Free-Electron-Laser (FEL) XUV sources. The measured pulse duration in the attosecond pulse train is 650 ± 80 asec. The uniqueness of the combined high intensity and short pulse duration of the source is evidenced in non-linear XUV-optics experiments. It further advances the implementation of XUV-pump-XUV-probe experiments and enables the investigation of strong field effects in the XUV spectral region.

Patients' intention to consume prescribed and non-prescribed medicines: A study based on the theory of planned behaviour in selected European countries.

WHAT IS KNOWN AND OBJECTIVE: Polypharmacy has a significant impact on patients' health with overall expenditure on over-the-counter (OTC) medicines representing a substantial burden in terms of cost of treatment. The aim of this study, which was conducted within the framework of a European Project funded by the European Union under the Seventh Framework Programme and was entitled OTC-SOCIOMED, was to report on possible determinants of patient behaviour regarding the consumption of medicines, and particularly OTCs, in the context of primary care. METHODS: A multicentre, cross-sectional study was designed and implemented in well-defined primary healthcare settings in Cyprus, the Czech Republic, France, Greece, Malta and Turkey. Patients completed a questionnaire constructed on the basis of the theory of planned behaviour (TPB), which was administered via face-to-face interviews. RESULTS AND DISCUSSION: The percentage of patients who had consumed prescribed medicines over a 6-month period was consistently high, ranging from 79% in the Czech Republic and 82% in Turkey to 97% in Malta and 100% in Cyprus. Reported non-prescribed medicine consumption ranged from 33% in Turkey to 92% in the Czech Republic and 97% in Cyprus. TPB behavioural antecedents explained 43% of the variability of patients' intention to consume medicines in Malta and 24% in Greece, but only 3% in Turkey. Subjective norm was a significant predictor of the intention to consume medicines in all three countries (Greece, Malta and Turkey), whereas attitude towards consumption was a significant predictor of the expectation to consume medicines, if needed. WHAT IS NEW AND CONCLUSION: This study shows that parameters such as patients' beliefs and influence from family and friends could be determining factors in explaining the high rates of medicine consumption. Factors that affect patients' behavioural intention towards medicine consumption may assist in the formulation of evidence-based policy proposals and inform initiatives and interventions aimed at increasing the appropriate use of medicines.

Fate of natural organic matter at a full-scale Drinking Water Treatment Plant in Greece.

The aim of this study was to investigate the fate of natural organic matter (NOM) and subsequent changes during the various treatment processes at a full-scale Drinking Water Treatment Plant (DWTP). Monthly sampling campaigns were conducted for 1 year at six sites along DWTP of Thessaloniki, Northern Greece including raw water from the Aliakmonas River that supplies DWTP and samples from various treatment processes (pre-ozonation, coagulation, sand filtration, ozonation, and granular activated carbon (GAC) filtration). The concentration of NOM and its characteristics as well as the removal efficiency of various treatment processes on the basis of dissolved organic carbon, UV absorbance, specific ultra-violet absorbance, fluorescence intensity, hydrophobicity, biodegradable dissolved organic carbon, and formation potential of chlorination by-products trihalomethanes (THMs) and haloacetic acids (HAAs) were studied. The concentration of dissolved organic carbon (DOC) in reservoir of the Aliakmonas River ranged from 1.46 to 1.84 mg/L, exhibiting variations regarding UV, fluorescence, and hydrophobic character through the year. Along DWTP, a significant reduction of aromatic, fluorophoric, and hydrophobic character of NOM was observed resulting in significant elimination of THM (63%) and HAAs (75%) precursors.

An improved optical flow tracking technique for real-time MR-guided beam therapies in moving organs.

Magnetic resonance (MR) guided high intensity focused ultrasound and external beam radiotherapy interventions, which we shall refer to as beam therapies/interventions, are promising techniques for the non-invasive ablation of tumours in abdominal organs. However, therapeutic energy delivery in these areas becomes challenging due to the continuous displacement of the organs with respiration. Previous studies have addressed this problem by coupling high-framerate MR-imaging with a tracking technique based on the algorithm proposed by Horn and Schunck (H and S), which was chosen due to its fast convergence rate and highly parallelisable numerical scheme. Such characteristics were shown to be indispensable for the real-time guidance of beam therapies. In its original form, however, the algorithm is sensitive to local grey-level intensity variations not attributed to motion such as those that occur, for example, in the proximity of pulsating arteries.In this study, an improved motion estimation strategy which reduces the impact of such effects is proposed. Displacements are estimated through the minimisation of a variation of the H and S functional for which the quadratic data fidelity term was replaced with a term based on the linear L(1)norm, resulting in what we have called an L(2)-L(1) functional.The proposed method was tested in the livers and kidneys of two healthy volunteers under free-breathing conditions, on a data set comprising 3000 images equally divided between the volunteers. The results show that, compared to the existing approaches, our method demonstrates a greater robustness to local grey-level intensity variations introduced by arterial pulsations. Additionally, the computational time required by our implementation make it compatible with the work-flow of real-time MR-guided beam interventions.To the best of our knowledge this study was the first to analyse the behaviour of an L(1)-based optical flow functional in an applicative context: real-time MR-guidance of beam therapies in moving organs.

Occurrence and fate of ozonation by-products at a full-scale drinking water treatment plant.

The occurrence and fate of carbonyl compounds as ozonation by-products at a full scale drinking water treatment plant (DWTP) were studied for one year. Raw water and samples after the main treatment processes (pre-ozonation, coagulation/flocculation, sand filtration, main ozonation, filtration through granular activated carbon and chlorination) were collected on a monthly basis. Pre-ozonation led to the formation of carbonyl compounds at concentrations of 67.3 ± 43.3 µg/l as sum of 14 carbonyl compounds whereas lower concentrations were determined after the main ozonation process, 32.8 ± 22.3 µg/l. The dominant compounds were formaldehyde, acetaldehyde, glyoxal and methyl glyoxal contributing to 65% of total carbonyl content. The DOC reactivity in formation of carbonyl compounds varied through the year exhibiting the higher values in spring. Coagulation/flocculation and sand filtration significantly removed (64-80%) the carbonyl compounds formed at the pre-ozonation step. The removal efficiency of filtration through granular activated carbon showed great variation ranging from 15 to 62%. Finally, the concentrations of carbonyl compounds in finished water were low, close to detection limits, revealing the efficiency of DWTP in the removal of this class of ozonation by-products.

Perceptions of primary care professionals on quality of services in rural Greece: a qualitative study.

INTRODUCTION: Greece is striving to limit its health expenditure to essential needs. General practice and the provision of Primary Health Care (PHC) mainly take place in rural settings, where approximately 200 Primary Health Care Centres (PHCCs) have been established. In order to determine how to optimize the effectiveness and efficiency of PHC services, it is important to first gain insights into the providers' perspectives. The aim of the study was to assess the perceptions of General Practitioners (GPs) and the directors of PHCCs regarding the effectiveness of available PHC services, and to elicit suggestions on how current services could be improved. METHODS: This qualitative study was based on semi-structured interviews. The setting was 21 PHCCs in the Epirus and Crete regions of Greece. Twenty-nine physicians were interviewed on aspects of capacity, resources, performance and quality of PHC services. Discussions were digitally recorded and transcribed verbatim. The transcriptions were then analysed using thematic content analysis. RESULTS: The main identified barriers to providing high-quality PHC services were: PHC service shortages in workforce and equipment; inadequate GP and paramedic training; the absence of position/job descriptions or duty statements for GPs and other PHC personnel; and limited public awareness about the role of GPs. Suggestions for remodelling the current PHC system included: the introduction of new technologies; GP empowerment; leadership reforms; and mechanisms for evaluating of the quality of services. Finally, areas of concern regarding future development and utilisation of private PHC infrastructure and services were highlighted. CONCLUSION: The methodology of this study and the results regarding remodelling the current PHC system could be used to inform policy-making in Greece, particularly in the current period of severe economic crisis; they may also be of relevance to other European countries facing similar challenges in allocating resources and reforming PHC.

Analysis of fatal motor vehicle collisions: evidence from Central Macedonia, Greece.

BACKGROUND: The objective of this study was to assess the factors associated with the traffic mortality in the region of Central Macedonia in order to produce evidence in building up preventive policies. MATERIAL AND METHODS: This study is a descriptive survey covering a three-year period (from 01-01-2006 to 31-12- 2008). The data used were supplied by the regional Road Traffic Police Service in Thessaloniki. RESULTS: A total of 280 fatal vehicle collisions were recorded in three years, in which 312 people died. 266 (85.26%) of the 312 people who died were men and 46 (14.74%) were women. The victims were between 1 and 91 years of age (mean ± SD, 42.00 ± 20.36 years). More fatal vehicle collisions were recorded on weekends and holidays than weekdays. Regarding the type of the vehicle, occupants of two-wheeled motor vehicles were in greater risk for dying compared to heavy duty vehicle passengers, who are considered to be protected by the vehicle. Among the 312 fatalities, alcohol was detected in 87 (28%) of the drivers who were responsible for the collision. Most of them (56/86, 64.4%) were between 15 and 44 years of age. In 6 (1.9%) cases, all of them drivers, illicit substances were detected. Vehicle collisions with younger victims were recorded during the early morning hours, whereas older people died more frequently during daytime. CONCLUSIONS: The findings of this study are providing evidence for the design and implementation of concrete and urgently needed preventive strategies in order to control the almost completely preventable fatalities of the road crashes.

A variational model for histogram transfer of color images.

In this paper, we propose a variational formulation for histogram transfer of two or more color images. We study an energy functional composed by three terms: one tends to approach the cumulative histograms of the transformed images, the other two tend to maintain the colors and geometry of the original images. By minimizing this energy, we obtain an algorithm that balances equalization and the conservation of features of the original images. As a result, they evolve while approaching an intermediate histogram between them. This intermediate histogram does not need to be specified in advance, but it is a natural result of the model. Finally, we provide experiments showing that the proposed method compares well with the state of the art.

Influence of acute anterior cruciate ligament deficiency in gait variability.

The objective of this study was to compare the gait variability of patients with isolated anterior cruciate ligament (ACL) deficiency (experimental group) with that of healthy individuals (control group). The hypothesis was that the gait variability of the experimental group would be higher than the control group. The experimental group consisted of 20 men with an ACL tear and the control group consisted of 20 healthy men without any neurological and/or musculoskeletal pathology or injury. The gait acceleration signal was analysed using the Gait Evaluation Differential Entropy Method (GEDEM). The GEDEM index of the experimental group in the medio-lateral axis was significantly higher than that of the control subjects. A receiver operating characteristic (ROC) analysis was used to assess the diagnostic value of the method and to determine a cut-off entropy value. The GEDEM cut-off value had a 95.6% probability of separating isolated ACL patients from healthy subjects.

Time trends of female breast cancer mortality in Greece during 1980-2005: a population based study.

BACKGROUND: Changes in female breast cancer mortality trends have been observed in recent years in western countries. The aim of the present study was to analyse breast cancer mortality in Greece, between 1980 and 2005. METHODS: Time trends of breast cancer mortality were calculated per 100,000 women in the whole female population of Greece, in different age groups, and in different areas of the country. Mortality data and population age distribution were provided by the National Statistical Service of Greece. RESULTS: Overall, female breast cancer mortality in Greece had an increasing trend during 1980-2005. Subgroup analysis according to age showed that this increase was confined to women older than 70 years. In contrast, a mild decrease was noted after the mid-1990s in women 40-69 years old. There were no notable regional differences in breast cancer mortality. CONCLUSIONS: The increasing trend of breast cancer mortality in women aged 70 years and older could be attributed to limited use of secondary prevention methods and rare administration of systemic cytotoxic chemotherapy in these women. In contrast, implementation of these strategies could explain the recent reduction of breast cancer mortality in younger age groups.

Corpus callosum morphology and microstructure assessed using structural MR imaging and diffusion tensor imaging: initial findings in adults with neurofibromatosis type 1.

BACKGROUND AND PURPOSE: Imaging studies have shown that children with NF-1 have increased brain volumes compared with age-matched controls and the CCs are disproportionately large. The purpose of this study was to determine if the CC in adults with NF-1 differed from that in matched controls by using DTI and volumetric imaging. MATERIALS AND METHODS: MR imaging with DTI was performed in 10 adults with NF-1 and in 10 age-, sex-, and handedness-matched controls by using a 3T system. Total brain volumes and the areas and central lengths of the CC were calculated, along with the radial width of callosal subdivisions, in the 2 groups. RESULTS: Our results showed that the total brain volume was not significantly different between adults with NF-1 and matched controls. The length and total cross-sectional area of the CC were statistically larger in adults with NF-1 compared with controls (approximately 10% longer and 20% greater area). On DTI we found a preservation of the primary eigenvalue with increases in the minor eigenvalues at the genu. CONCLUSIONS: We have shown that the increased size of the CC found in children with NF-1 is also present in adults with the syndrome, whereas no difference in total brain volume was found.

Gait variability measurements in lumbar spinal stenosis patients: part A. Comparison with healthy subjects.

The objective of this study is to compare the gait variability of patients with lumbar spinal stenosis (experimental group) with healthy individuals (control group). The hypothesis is that the preoperative gait variability of the experimental group is higher than the control group. The experimental group consisted of 35 adults (18 males, 17 females). The subjects of the experimental group suffered exclusively from spinal stenosis. The patients were determined by MRI scans. A tri-axial accelerometer sensor was used for the gait measurement, and differential entropy algorithm was used to quantify the gait acceleration signal. The Oswestry Low Back Pain Questionnaire was used to determine the condition on the day of the measurement. Receiver operating characteristic (ROC) was utilized to assess the diagnostic value of the method and determine a cut-off value. There is a statistically significant difference between gait variability in the control group and the experimental group. ROC analysis determines a cut-off differential entropy value. The cut-off value has a 97.6% probability of separating patients with spinal stenosis from healthy subjects. The Oswestry Low Back Questionnaire is well correlated with the spectral differential entropy values.

Gait variability measurements in lumbar spinal stenosis patients: part B. Preoperative versus postoperative gait variability.

The objective of this study was to assess the gait variability of lumbar spinal stenosis (LSS) patients and to evaluate its postoperative progression. The hypothesis was that LSS patients' preoperative gait variability in the frequency domain was higher than the corresponding postoperative. A tri-axial accelerometer sensor was used for the gait measurement and a spectral differential entropy algorithm was used to measure the gait variability. Twelve subjects with LSS were measured before and after surgery. Preoperative measurements were performed 2 days before surgery. Postoperative measurements were performed 6 and 12 months after surgery. Preoperative gait variability was higher than the corresponding postoperative. Also, in most cases, gait variability appeared to decrease throughout the year.

Accelerometry for evaluation of gait pattern in healthy soccer athletes.

An accelerometer system was used to measure the characteristics of the motion of 133 healthy male soccer athletes in a 30-s walking test and the data obtained were analysed using the gait evaluation differential entropy method (GEDEM). GEDEM processes gait acceleration data and calculates an index that provides a quantitative evaluation of a subject's gait, at low cost and with negligible effect on the subject. The GEDEM index was not significantly correlated with age, body weight, body mass index, or the number of years of active training. The GEDEM value for the anterior-posterior axis showed a small negative statistically significant correlation with height and the vertical axis was moderately and statistically significantly positively correlated with the time spent training per week. The triaxial accelerometry system described here is easy for subjects and testers to use, and enables measurements to be made on the sports field to evaluate an athlete's musculoskeletal condition with respect to gait stability.

Optimal treatment of a recurrent giant craniopharyngioma: lessons from a case.

A case of a 33-year-old man presented with symptoms of dramatic deterioration of the level of consciousness because of a recurrence of a previously aspirated and irradiated craniopharyngioma is described. The tumor had grown enormously in dimensions and was extending in the region of hypothalamus, third ventricle and brain stem, with signs of local compression and obstructive hydrocephalus. Radical surgical excision, despite the size and the location of the lesion, was the therapy of choice. The surgical technique is described. We conclude that in expert hands, microsurgery aiming at total removal should be the therapeutic option for the treatment of recurrent as well as primary craniopharyngiomas.

Suprasellar and intrasellar paragangliomas.

Neoplasms of the sellar region are entities with a large differential diagnosis. Although paraganglionic cells have not been demonstrated in the pituitary or adjacent structures, the existence of sellar region paragangliomas is well-documented. To elucidate, in this area the nature of these unusual tumors is relatively difficult. Clinical history, physical examination, radiographic investigation as well as intraoperative gross observation are the same as those of sellar meningioma or pituitary adenoma. Immunohistochemistry, using neuroendocrine markers and electron microscopy are the two definitive diagnostic methods to differentiate among these entities. The clinical management, the possible pathogenesis of the tumor, the importance of immunohistochemistry in making the diagnosis and the clinical outcome of these patients are discussed.

Diffusion tensor imaging for the assessment of upper motor neuron integrity in ALS.

BACKGROUND: High angular resolution diffusion tensor imaging (HARD) is an MRI technique that exploits the mobility of water molecules to yield maps of structural order and directionality of white matter tracts with greater precision than six-direction diffusion tensor imaging (DTI) schemes. OBJECTIVE: To assess whether HARD is more sensitive than conventional MRI or neurologic assessment in detecting the upper motor neuron (UMN) pathology of patients with ALS. METHODS: Twenty-five patients with definite UMN clinical signs and 23 healthy volunteers underwent conventional MRI. HARD datasets were collected from a subset of these participants plus four patients with isolated lower motor neuron (LMN) signs. ALS symptom severity was assessed by a neurologist, the conventional MR images were reviewed by neuroradiologists, and the DTI maps were subject to quantitative region of interest analysis. RESULTS: Motor cortex hypointensity on T2-weighted images and corona radiata hyperintensity on proton density-weighted images distinguished patients with UMN involvement from volunteers with 100% specificity, but only 20% sensitivity. Fractional anisotropy (FA) was reduced in the posterior limb of the internal capsule in patients with UMN involvement compared to volunteers. A FA threshold value with a sensitivity of 95% to detect patients with ALS (including those with isolated LMN signs) had a specificity of 71%. CONCLUSIONS: High angular resolution diffusion tensor imaging may be more sensitive than conventional MRI or neurologic assessment to the upper motor neuron (UMN) pathology of ALS, but it lacks the specificity required of a diagnostic marker. Instead, it is potentially useful as a quantitative tool for monitoring the progression of UMN pathology.

A method of generalized projections (MGP) ghost correction algorithm for interleaved EPI.

Investigations into the method of generalized projections (MGP) as a ghost correction method for interleaved EPI are described. The technique is image-based and does not require additional reference scans. The algorithm was found to be more effective if a priori knowledge was incorporated to reduce the degrees of freedom, by modeling the ghosting as arising from a small number of phase offsets. In simulations with phase variation between consecutive shots for n-interleaved echo planar imaging (EPI), ghost reduction was achieved for n = 2 only. With no phase variation between shots, ghost reduction was obtained with n up to 16. Incorporating a relaxation parameter was found to improve convergence. Dependence of convergence on the region of support was also investigated. A fully automatic version of the method was developed, using results from the simulations. When tested on in vivo 2-, 16-, and 32-interleaved spin-echo EPI data, the method achieved deghosting and image restoration close to that obtained by both reference scan and odd/even filter correction, although some residual artifacts remained.

Analysis of diffusion tensor magnetic resonance imaging data using principal component analysis.

An analysis method for diffusion tensor (DT) magnetic resonance imaging data is described, which, contrary to the standard method (multivariate fitting), does not require a specific functional model for diffusion-weighted (DW) signals. The method uses principal component analysis (PCA) under the assumption of a single fibre per pixel. PCA and the standard method were compared using simulations and human brain data. The two methods were equivalent in determining fibre orientation. PCA-derived fractional anisotropy and DT relative anisotropy had similar signal-to-noise ratio (SNR) and dependence on fibre shape. PCA-derived mean diffusivity had similar SNR to the respective DT scalar, and it depended on fibre anisotropy. Appropriate scaling of the PCA measures resulted in very good agreement between PCA and DT maps. In conclusion, the assumption of a specific functional model for DW signals is not necessary for characterization of anisotropic diffusion in a single fibre.