2-Dimensional Clay/Reduced Graphene Oxide Ordered Heterostructures Dispersible in Water via a One-Step Hydrothermal Route.

A facile and green method for trapping the hydrophobic reduced graphene oxide between the hydrophilic Kunipia F layers in order to attain stable aqueous dispersions of reduced graphene oxide is described. Initially stable aqueous dispersions of hydrophilic clay intercalated with hydrophilic graphene oxide sheets were formed providing well-organized heterostructures, as it was revealed by scanning electron microscopy images. These structures were preserved in the product obtained after hydrothermal treatment where the hydrophilic graphene oxide was converted to hydrophobic reduced graphene oxide. Ultraviolet measurements revealed the aforementioned conversion which was accompanied by a characteristic change in color from yellow-brown to black in the corresponding aqueous dispersions of these hybrids before and after hydrothermal treatment. The stability of these homogeneous dispersions was confirmed by Zeta Potential measurements implying interactions both in cases of graphene oxide and reduced graphene oxide with clay sheets that made feasible the effective interstratification of graphene-clay layered materials. In these stable dispersions chemistry in aqueous environment could be fully utilized making possible their incorporation e.g., as fillers to hydrophilic polymeric matrices extending thus the limits of application.

Post-treatment of molasses wastewater by electrocoagulation and process optimization through response surface analysis.

Molasses wastewater is a high strength effluent of food industry such as distilleries, sugar and yeast production plants etc. It is characterized by a dark brown color and exhibits a high content in substances of recalcitrant nature such as melanoidins. In this study, electrocoagulation (EC) was studied as a post treatment step for biologically treated molasses wastewater with high nitrogen content obtained from a baker's yeast industry. Iron and copper electrodes were used in various forms; the influence and interaction of current density, molasses wastewater dilution, and reaction time, on COD, color, ammonium and nitrate removal rates and operating cost were studied and optimized through Box Behnken's response surface analysis. Reaction time varied from 0.5 to 4 h, current density varied from 5 to 40 mA/cm(2) and dilution from 0 to 90% (v/v expressed as water concentration). pH, conductivity and temperature measurements were also carried out during each experiment. From preliminary experiments, it was concluded that the application of aeration and sample dilution, considerably influenced the kinetics of the process. The obtained results showed that COD removal varied between 10 and 54%, corresponding to an operation cost ranging from 0.2 to 33 euro/kg COD removed. Significant removal rates were obtained for nitrogen as nitrate and ammonium (i.e. 70% ammonium removal). A linear relation of COD and ammonium to the design parameters was observed, while operation cost and nitrate removal responded in a curvilinear function. A low ratio of electrode surface to treated volume was used, associated to a low investment cost; in addition, iron wastes could be utilized as low cost electrodes i.e. iron fillings from lathes, aiming to a low operation cost due to electrodes replacement. In general, electrocoagulation proved to be an effective and low cost process for biologically treated molasses-wastewater treatment for additional removal of COD and nitrogen content and color reduction. Treated effluent samples with good quality were produced by EC, with COD, NH4-N and NO3-N concentrations of 180, 52 and 2 mg/l respectively. Response surface analysis revealed that optimized conditions could be established under moderate molasses wastewater dilution, (e.g. 45%), at 3.5 h treatment time and 33 mA/cm(2) current density.

Protozoans as indicators of sequential batch processes for phenol treatment; an autoecological approach.

The objective of this study was the investigation of the potential use of protistan species as quality indicators of the activated sludge performance in sequential batch processes receiving toxic compounds. Two laboratory scale sequential batch reactors (SBR) were used, a conventional one and a system with plastic biofilm carriers (SBBR), treating wastewater containing phenol at concentrations ranging from 1 up to 40 mg/L. Physicochemical analyses of the samples included the determination of MLSS, effluent suspended solids, BOD5, nitrogen-ammonia, nitrogen-nitrate and phenol. The activated sludge protistan community was identified and enumerated in each reactor. Statistical analyses included Canonical Correspondence Analysis and Indicator Species Analysis of the collected experimental data. Canonical Correspondence Analysis showed inversely proportional relationships between the protozoa and the physicochemical parameters of the effluent as well as protozoan species competition. Indicator species analysis revealed the presence and the prevalence of different species under various phenol influent concentrations. No indicator species were observed for the period of operation under 5 mg/L influent phenol in both reactors, while no indicator species were observed for 20 mg/L influent phenol in the SBR reactor. Carchesium and Epistylis sp. showed the higher values for 1 mg/L phenol in the SBR, while Holophrya sp. showed lower indicator values for the same period in the SBBR. Although several species showed a good correlation to the treatment efficiency of the reactors, Blepharisma sp., could be used as the primary indicator species in both reactors for the operation period under 40 mg/L phenol, as deduced by statistical analysis.

Synthesis and magnetic properties of Fe3O4 nanoparticles coated with biocompatible double hydrophilic block copolymer.

Fe3O4 nanoparticles coated with double hydrophilic biocompatible poly(sodium(2-sulfamate-3-carboxylate)isoprene)-b-poly(ethylene oxide) block copolymer were prepared by a one step precipitation method. The magnetic nanoparticles have 15 nm mean diameter (TEM), 68 nm hydrodynamic diameter, -30.10 mV zeta-potential and form very stable dispersion in aqueous media. Structural characterization using powder XRD and Mössbauer spectroscopy establish the magnetite phase, while thermogravimetric analysis and FT-IR spectroscopy confirm the presence of the block copolymer on the nanoparticles surface. The magnetic properties were determined using a vibrating sample magnetometer (VSM) at room temperature and reveal superparamagnetic behavior while the composite materials shows high saturation magnetization up to 67.7 emu/gr.

A general chemical route for the synthesis of capped nanocrystalline materials.

Noble metals, magnetic and semiconducting nanocrystalline materials have been synthesized via the thermolytic decomposition of inorganic metal salts, at high temperature, in commercial oleyl amine. The oleyl amine acts as high boiling point coordinating solvent, capping agent and, when required, as reducing agent. The crystal structure and morphology of the nanostructured materials have been studied with powder X-ray analysis (XRD) and transmission electron microscopy (TEM). The particles are well dispersed in non polar solvents such as hexane, toluene and chloroform and have uniform morphology.

Magnetic properties of gamma-Fe2O3/poly(ether-ester) nanocomposites.

The magnetic properties of gamma-Fe2O3 nanoparticles embedded in a thermoplastic elastomer poly(ether-ester) copolymer by the in situ polycondensation reaction process have been investigated by means of magnetization and ferromagnetic resonance (FMR) measurements at low filler concentrations of 0.1 and 0.3 wt% with the magnetic additive introduced in the polymer matrix in powder and solution form. The magnetic behavior of the magnetopolymeric nanocomposites indicates significant interparticle interaction effects that depend mainly on the dispersion state of the magnetic nanoparticles as well as their concentration, consistent with the variation of the particle microstructure characterized by magnetic aggregates in the nanometer and micron scale for the solution and powder dispersions, respectively. The magnetization and FMR results at different filler concentrations and dispersions show a close correspondence to the relaxation processes of the copolymer, implying the coupling of polymeric and magnetic properties.

One-step solid state synthesis of capped γ-Fe(2)O(3) nanocrystallites.

The thermally induced solid state synthesis of soluble organophilic maghemite (γ-Fe(2)O(3)) nanocrystallites is described. The solvent-free one-step synthesis involves the reaction in the melt state of Fe(NO)(3)·9H(2)O and RCOOH (R = C(11)H(23), C(15)H(31)) at 240 °C. The method yields well-crystallized nanoparticles of γ-Fe(2)O(3) functionalized with the corresponding aliphatic acid. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) observations reveal composite particles with faceted magnetic cores and average size of 20 nm, which are well capped with the surrounding organic sheath. The Fourier transform infrared (FT-IR) spectra and thermal analysis suggest a bimodal configuration of the organic shell including chemically coordinated and physisorbed molecules of aliphatic acid. The chemical bonding of the carboxylate groups to the surface iron atoms is also indicated by a paramagnetic doublet with unchanged area in the variable temperature Mössbauer spectra. The spinel γ-Fe(2)O(3) particles exhibit perfect structural and magnetic ordering, including the almost ideal ratio of octahedral to tetrahedral positions (5/3) and very low degree of spin canting, as confirmed by in-field Mössbauer spectroscopy. Magnetic measurements demonstrate the suitable properties required in various (bio)magnetic applications like superparamagnetic behavior at room temperature, high saturation magnetization achievable at low applied fields and suppressed magnetic interactions.

Large-scale synthesis, size control, and anisotropic growth of gamma-Fe2O3 nanoparticles: organosols and hydrosols.

Monodispersed, spherical gamma-Fe2O3 nanoparticles with controllable size in large-scale were prepared by thermolytic decomposition of FeCl3.6H2O in aliphatic amines. The nanoparticles gave very stable colloidal solution in organic solvents and can be easily converted to water-soluble by a very simple route. Their characterisation was based on TEM microscopy, XRD, Mössbauer, and magnetic measurements. Furthermore, a small amount of Pt can lead to the formation of anisotropic gamma-Fe2O3 nanostructures.

Synthesis and characterization of monodispersed rhodium nanoparticles organized in 3-D symmetrical structures soluble in organic media.

Monodispersed rhodium nanoparticles were synthesized through a flexible and very simple approach in a monosurfactant system by thermolysis of RhCl3, in which oleyl amine serves as capping, reducing agent, and high boiled solvent. The coated rhodium nanoparticles are monodispersed with 4 nm diameter and well characterised by TEM microscopy, UV-Vis spectroscopy, and X-ray diffraction measurements. The as prepared rhodium nanoparticles have the tendency to aggregate forming well-organized large symmetrical and spherical 3-D superstructures which generally have diameters between 40-60 nm as revealed by the characteristic TEM images. Due to the organic monolayer that encloses the nanoparticles are soluble in non-polar organic solvents.

Laryngeal tuberculosis presenting as supraglottic carcinoma: case report and literature review.

Laryngeal tuberculosis is a rare extra-pulmonary manifestation of tuberculosis, and frequently presents with tumour-like symptoms and clinical findings. Uncommon clinical features are to be expected by the ENT specialist, who should be aware of these recently changing presentations. Despite the dramatic reduction of the incidence of the disease during the last few decades, a perceptible increase in case reports has lately been noted and may prove significant. Treatment remains conservative and long-term follow-up is suggested. A relevant case of laryngeal tuberculosis presenting as a supraglottic carcinoma is presented, its diagnosis and management are detailed, and suggestions are offered based on a literature review.

Gonadal changes and blood sex steroids levels during natural sex inversion in the protogynous Mediterranean red porgy, Pagrus pagrus (Teleostei: Sparidae).

Changes in gonadal structure and serum levels of sex steroids were investigated during natural sex inversion from female to male in reared populations of the protogynous Mediterranean red porgy, Pagrus pagrus. Four developmental phases were identified by histological observation: female, early transitional (ETr), late transitional (LTr), and male phases. At female phase, a few nests of spermatogonia were observed at the posterior-ventral part of the gonad mainly in females out of the breeding season. At ETr phase, spermatogonial proliferation occurred while perinucleolar oocytes showed signs of degeneration. At LTr phase, seminiferous lobules were formed and spermatogonial proliferation expanded along the ovary which degenerated. All types of male germ cells could be found. At male phase, functional testis underwent active spermatogenesis while small ovarian remnants associated to fat tissue could be detected. Both 17beta-estradiol (E2) and estrone (E1) blood levels were significantly lower in fish at transitional and male phases in comparison to breeding females, while levels of 11-ketotestosterone (11-KT) and testosterone (T) gradually increased in the transitional and male phases. In conclusion, the protogynous P. pagrus possess a delimited type bisexual gonad with a medio-dorsal ovarian area and a latero-ventral testicular zone. Sex inversion starts mainly after the female breeding season with an active spermatogonial proliferation. The testis tissues develop while ovarian tissues regress to disappear completely in the functional male. This process is accompanied by a sharp decrease of estrogens levels and a progressive increase of androgens levels. The physiological significance of such endocrine changes is discussed.

The effect of Mn doping in FePt nanoparticles on the magnetic properties of the L1(0) phase.

FePtMn nanoparticles with a narrow size distribution and an average diameter of 3 nm were synthesized by the chemical reduction of Fe(acac)(3) and Pt(acac)(2) by NaBH(4) and the thermal decomposition of Mn(2)(CO)(10) in phenyl ether. The as-made nanoparticles have a disordered face-centred cubic (fcc) structure, which transformed after thermal treatment at 650 °C to an ordered face-centred tetragonal (fct) structure, possessing coercivity values up to 13.7 kOe at room temperature. The coercivity of the annealed samples depends on the amount of Mn added to the reaction mixture, with the coercive field increasing significantly with the partial substitution of Pt by Mn, while the partial substitution of Fe by Mn does not affect the magnetic properties strongly.

Factors influencing tumour relapse after total laryngectomy.

OBJECTIVES: To determine the prognostic factors predictive of tumour recurrence after surgical treatment for laryngeal carcinoma with total laryngectomy. STUDY DESIGN/METHODS: Retrospective review of 308 patients with laryngeal carcinoma who underwent total laryngectomy in the ENT Department of AHEPA University Hospital between 01/01/1992 and 31/12/1999. In 238 patients, total laryngectomy was performed as primary treatment of laryngeal carcinoma, and in 70 others as treatment of tumour recurrence following radiotherapy or partial surgery. Follow-up was standardized, following a strict protocol, the mean follow-up time was 68 months. RESULTS: During post-operative follow-up, recurrences were observed in 96 of 308 patients (31%). The relapse rates were 27% (65 of 238) for patients treated with primary total laryngectomy, and 44% (31 of 70) for those treated for recurrence following previous treatment. The difference in relapse rates was statistically significant. In 39 of 238 (16%) cases treated with primary total laryngectomy cervical lymph node infiltration was present at diagnosis and radical or modified neck dissection was performed. The tumour recurrence rate in this group was 46% (18 of 39), while in metastatic node-free patients the relapse rate was 24% (47 of 199) [p < 0.05]. Primary laryngectomy was effective in 82% of glottic, 70% of supraglottic, and only 59% of transglottic carcinoma. Concerning primary tumour extension at the time of surgery, total laryngectomy proved effective in 85% of T2 tumours, 81% of T3, and only 55% for T4. The higher recurrence rates for supraglottic and transglottic tumours seem related mainly to the higher rates of cervical lymph node metastasis at diagnosis. The majority of tumour recurrences were observed during the first two years of post-operative follow-up. Thus, 76% of the 308 patients remained disease-free after the first year of post-operative follow-up, 68% after the second year, and 67% after the fifth follow-up year. Of the 96 recurrences documented until now, 91 were loco-regional (19 at the tracheostomy), and only 5 involved distant metastases. Sixteen of the 308 patients (5%) subjected to total laryngectomy have since developed second primary neoplasms, most often involving the lungs (10 patients). CONCLUSIONS: Prognostic factors for recurrence following total laryngectomy include: performance of total laryngectomy as salvage surgery, degree of tumour extension, infiltration of cervical lymph nodes at the time of initial diagnosis, poor initial tumour differentiation and trans-glottic/sub-glottic tumour localization.

The prevalence of the metabolic syndrome in Greece: the MetS-Greece Multicentre Study.

BACKGROUND: The Third Report (ATP III) of the National Cholesterol Education Program Expert Panel (NCEP) highlighted the importance of identifying and treating patients with the metabolic syndrome (MetS) to prevent cardiovascular disease (CVD) and progression to diabetes mellitus. Limited information is available about the prevalence of MetS, as defined by the NCEP ATP III, in Europe, especially in Greece. OBJECTIVE: To estimate the prevalence of the MetS in Greece, The MetS-Greece Study. DESIGN AND PARTICIPANTS: A cross-sectional analysis of a representative sample of Greek adults (4153 participants older than 18 years). One group consisting of military personnel (n = 300) and another one from a Greek Muslim Community (n = 300) were used for comparison. In all, 4753 subjects were included in the final analysis. RESULTS: All subjects from the general population were Caucasian men (49%) and women (51%), living in urban (n = 2243, 54%), semi-urban (n = 1038, 25%) and rural (n = 872, 21%) areas. The age-standardized prevalence of the MetS was 23.6%[95% confidence interval (CI): 22.4-25.1%]. This was similar in men (24.2%, 95% CI: 22.3-25.2%) and women (22.8%, 95% CI: 21.4-25.0%) (p = 0.3). The prevalence increased with age in both sexes, 4.8% among participants aged 19-29 years and 43% for participants over 70 years old (p for trend < 0.0001). There was a 14.7-fold increase in odds ratio for having MetS in the age group > 70 years old compared with that of 19-29 years old (p < 0.0001) Most of those with MetS had three components of the syndrome (61%), 29% had four and 10% had all five components. Abdominal obesity (82%) and arterial hypertension (78%) were the most common abnormalities in both sexes. The Greek Muslim Community, on a high-saturated fat diet, had the highest prevalence of the MetS (35.2%, 95% CI: 30.4-40.3%), and the military group, with a high physical activity level and a diet 'close' to Mediterranean, had the lowest (9.4%, 95% CI: 6.2-13.1%). According to the 2001 Census, about 2.3 million Greeks may have the MetS. CONCLUSIONS: These results show that the MetS is highly prevalent in the Greek adult population. This may have major implications for the incidence of CVD. Promoting healthy diets, low caloric intake and physical activity must be urgently undertaken.

Aqueous and gaseous adsorption from montmorillonite-carbon composites and from derived carbons.

Clay-carbon composites and the carbons derived from demineralization of the clay template were examined for their aqueous adsorption properties (2,4,6-trichlorophenol and methylene blue) and for their gas adsorption/separation abilities regarding CO(2), CH(4), and N(2) gases. The sorption results are discussed in relation with their structural properties (surface area, pore width and volume, and surface chemistry). It was found that the properties of the adsorbents depend highly on the synthetic route, for instance, on the use of clay or H(2)SO(4) as structure mediating and activating agents, respectively. Particularly, the simultaneous use of clay and H(2)SO(4) leads to a synergistic action, which imparts to the final solids the highest sorption capacity and the best potential for separation of CO(2) from gaseous mixtures of CH(4) and N(2).

Copper and zinc in four freshwater fish species from Lake Pamvotis (Greece).

Lake ecosystems are vulnerable to heavy-metal pollution. Fish samples are considered as one of the most indicative factors, in freshwater systems, for the estimation of trace metals pollution potential. Lake Pamvotis (NW Greece) is a typical Mediterranean ecosystem of great importance in regard to biodiversity and to aesthetic value. The fish species found most commonly in the lake are Cyprinus carpio, Silurus aristotelis, Rutilus ylikiensis, and Carassius gibelio. The aim of the present study is to evaluate the level of contamination of two essential heavy metals (copper and zinc) appearing at high concentrations in lake water in the above four fish species. Metal concentrations were measured by atomic absorption spectroscopy in three different tissues (muscle, liver, gonads) in order to assess the fish contamination. A two-factor analysis of variance, based on the procedure of general linear models, was employed in which fish species (four levels) and fish tissue (three levels) were examined for potential influence on Cu and Zn concentrations. Differences between level means per factor were treated using Tukey's multiple comparisons of means. The study showed that C. carpio and R. ylikiensis presented the highest metal content. Tissues analysis revealed that liver and gonads accumulated the highest levels of Cu and Zn. Metal concentration in the edible part of the examined fish (muscle) were in the safety-permissible levels for human consumption.

Shape fabrication of millimeter-sized metal-containing carboxymethyl cellulose hollow capsules.

Dropwise addition of an aqueous carboxymethyl cellulose solution to a solution of a copper or iron salt in n-butanol, leads to self-assembled, permeable millimeter sized metal-ion derivatized carboxymethyl cellulose hollow capsules of uniform dimensions and different morphologies.

How often is total laryngectomy necessary for the treatment of T1 failures after radiotherapy or cordectomy?

Between 1992 and 1998, 547 patients (pts) with laryngeal SCC were diagnosed and treated in our department, 145 (27%) of whom presented with glottic tumors T1N0M0 (125 T1a and 20 T1b). Seventy-eight (54%) were treated surgically with cordectomy and 67 (46%) with radiotherapy. After a median follow-up time of 43 months, 22 (15.2%) of the 145 pts presented with recurrent disease. In more detail, 16 (13%) of the 125 T1a pts and 6 (30%) of the 20 T1b pts had recurrences. Among the 78 surgically treated patients only 4 (5%) had recurrence, while 18 (27%) of the radiotherapy group relapsed. The difference is statistically significant (log rank test, P = 0.0001 < 0.05). After salvage treatment, of the 67 pts of the radiotherapy group 57 (85%) remain disease-free, 49 (73%) retaining their larynx intact and 1 only having undergone cordectomy. Among the cordectomy group 75 (96%) pts remain disease-free with only 1 having had a total laryngectomy. Using the Kaplan-Meier method and calculating the disease-free survival regardless of salvage treatment, there is no doubt that surgical treatment statistically is more successful than radiotherapy (log rank test, P = 0.01 < 0.05). Analysis of parameters such as tumor differentiation and T1a or T1b staging, which indeed influence the overall recurrence rate, did not alter the favorable outcome after surgical treatment.

Factors influencing quality of life in laryngectomized patients.

The aim of this study is to estimate the quality of life postlaryngectomy. A questionnaire was used. Fifty-six patients were enrolled answering 26 questions. The mean age was 60.2 (40-76) years and median post-treatment time 43 (7-120) months. The most frequent complaints of the patients were increased bronchial discharge (66%) and reduced olfactory function (63%). Communication problems with strangers was mentioned by 57% and with their family by 29%. With regard to the psychological status, 30% were ashamed of their voice, 32% were ashamed of their appearance, 42% stated that they were rather depressed, and 30% were feeling lonely. More than 3 out of 4 patients believed that their everyday life had been altered. Half of the patients experienced financial difficulties and 37% were not participating in social meetings outside their house. Statistical analysis was used in order to calculate the severity of each category of problems which the patient faced using the scale from 0 to 1. The average grade for functional disorders was 0.31, for communication problems 0.47, for psychological problems 0.29, for social problems 0.27, and for financial problems 0.51.