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Bauxite residue (BR) is the main by-product of the alkaline production of alumina from bauxite containing significant amounts of valuable metals such as scandium that belongs to rare-earth elements (REEs), classified by the European Community as critical raw materials (CRMs). BR is considered a hazardous waste due to its huge volume and high alkalinity making its disposal a serious universal environmental problem. The recovery of scandium from Greek BR can be an excellent approach for waste management and resource efficiency of the waste using environmentally friendly biometallurgical methods. In this work, bioleaching of scandium from bauxite residue using the fungus Aspergillus niger was studied. Bioleaching experiments were performed using the Taguchi experimental design, in batch cultures with BR at various pulp densities (1, 5 and 10%, w/v), sucrose concentrations (40, 90 and 140 g/L) and fungus suspension of 2, 4, and 6% v/v under one-step bioleaching condition and subculturing. The highest Sc recovery equal to 46%, was achieved in 20 days at 1% pulp density. Biosorption phenomena were observed during the leaching process. Lactic, acetic, oxalic and citric were the main organic acids identified. Graphical Abstract

As installed photovoltaic panels (PVP) approach their end of life, the need for a sustainable recovery plan becomes imperative. This work aims to reuse Silicon from End-of-Life PVP as a potential catalyst/photocatalyst for wastewater treatment. PVPs were pretreated thermally (550°C for 30 min). The resulting mixture of glass, silicon, electrodes, and ash was separated into different fractions in a trommel. Recovered Silicon flakes were washed with water, acetone, ΗΝΟ3, and HF in order to obtain pure Si. Then Si was etched through a single stage Ag-assisted Chemical etching process and doped with copper. Doping was performed in aqueous HF solutions containing CuSO4. Photocatalytic reduction of Cr(VI) in the presence of 5mM citric acid was carried out in a 600 mL batch reactor irradiated by a Xenon 150W arc lamp as well as under dark conditions. It was found that in the presence of 1.2 g/L of the Si catalyst, Cr(VI) at an initial concentration of 15 mg/L can be reduced below detection limit (>99%),under dark conditions in 90-240 min, depending on the pH of the solution. Irradiation, however, was shown to inhibit the process, contrary to previous reports that had not examined catalysis in the dark.

Lignocellulosic biomass including agricultural and forestry residues such as willow sawdust could be used as feedstock for anaerobic digestion (AD). Hydrolysis has been shown to be the rate-limiting step in the case of AD of such substrates. Although being abundant, since the annual world production of biomass residues exceed 220 billion tons, the main obstacles of their use are the low yields attained, due to the recalcitrant nature of their lignocellulosic content. The application of a pretreatment process prior to AD could improve the hydrolysis and the total methane yield. In this study, hydrothermal pretreatment alone or in combination with HCl, at a chemical loading of 2 g /100 g TS was carried out as a pretreatment method to enhance anaerobic digestion of willow sawdust, through biochemical methane potential (BMP) experiments. For both pretreatment approaches, various temperatures (130.5-229.5 oC) and process times (15.6 -59.4 min) were studied. Following pretreatment, the insoluble solids and the hydrolysates were separated by filtration and fully characterized in terms of their structural and chemical characteristics. BMP experiments showed that the hydrothermal pretreatment alone or in combination with the acid enhanced the methane yields and the higher the temperature or process time, the higher the yields which were obtained.

The objective of the current work is to study the impact of the operational parameters' variation (HRT, OLR and T) on biomethane productivity in a periodic anaerobic baffled reactor (PABR). The feedstock used was a biomass product named food residue biomass (FORBI), which is dried and shredded source-separated household food waste. The PABR is an innovative, high-rate bioreactor. Apart from the hydraulic retention time (HRT) and the organic loading rate (OLR), an important operational parameter is the switching period (T) of the feeding compartment: when T is high, the bioreactor operation is similar to an anaerobic baffled reactor (ABR), while when it is low, the operation approaches that of an upflow anaerobic sludge blanket reactor (UASBR). Nine distinct experimental phases were conducted, during which the operational parameters of the PABR were consecutively modified: the HRT varied from 9 to 2.5 days, T between 2 days and 1 and finally the OLR from 1.24 gCOD/Lbioreactor*d to 8.08 gCOD/Lbioreactor*d. The maximum biomethane yield was 384 LCH4/kgFORBI corresponding to the operation at HRT = 5 d, OLR = 2.14 gCOD/Lbioreactor*d and T = 2 days. Similar efficiency (333 LCH4/kg­FORBI) was achieved at higher OLR (4.53 gCOD/Lbioreactor*d). Highlights The feedstock used was a biomass product food residue biomass (FORBI), which is dried and shredded food waste.; Periodic anaerobic baffled reactor (PABR), a high-rate bioreactor.; The switching period (T) of the feeding compartment gives the bioreactor the element of operational flexibility.; The PABR can efficiently operate at HRTs as low as 2.5 days, however, the highest biomethane yield was achieved under HRT of 5 d.

The scope of this paper was to examine the environmental and economic performance of alternative household fermentable waste (HFW) management scenarios. In Greece, the business-as-usual scheme for the management of HFW is its disposal in landfills as part of mixed waste. Within a HORIZON2020 called Waste4think a series of alternative approaches based on the benefits of source separation was developed. Specifically, source separated HFW is led to a drying/shredding plant, located in the municipality, for the production of a high-quality biomass product, which is called FORBI (Food Residue Biomass). Alternative approaches have been examined for the exploitation of FORBI: a simple alternative consists of the transportation of food waste (without drying/shredding) to the landfill, composting and covering the landfill’s layers with the produced compost. On the other hand, a set of technological alternatives examined are: one- and two-stage anaerobic digestion for the production of biogenic compressed natural gas (bio-CNG) and bio-hythane, composting and utilization of compost in the municipality, bio-ethanol production and pelletization. The alternatives have been assessed using Life Cycle Assessment and Life Cycle Costing tools. The results show that both the simple and the innovative alternatives proposed perform better than the baseline scenario both in economic and environmental terms.

Purpose: The acquisition of reliable data on Municipal Solid Waste (MSW) composition is very important for the development of environmentally sound, sustainable and economically viable integrated waste management systems. However, no standardized universally accepted waste characterization protocol has been developed, as there are various methodologies described in the relevant literature. In this study, a generic and easy-to-apply MSW sampling and sorting protocol is developed and presented. Methods: The MSW composition characterization was used for the development of an innovative waste management strategy in the Municipality of Halandri (Attica region, Greece). The methodology was applied four times, to study the repeatability of the results, as well as the potential impact of seasonality. In each sampling point one collection bin for each waste stream was employed (mixed waste, recyclables, paper/cardboard and food waste in the region where food waste was separately collected at the source) in order to collect all the separate streams and account for the entire MSW production profile. The sampling points were selected in strictly residential areas (no shops, companies nearby). For 7 consecutive days the content of the bins was collected on a daily basis and transported to a sorting facility, where the content was sorted and weighed. Results: The results repeatedly indicated source separation rates of up to 79% and a level of impurities in the recycling waste source separation and collection streams (recyclables and paper/cardboard) not exceeding 20%. Conclusion: The applied methodology proved to generate accurate results, offering a detailed picture of the Municipal Solid Waste management performance.

The rapid urbanization that took place in the last 60 years has led to a dramatic increase in the generation of Municipal Solid Waste (MSW). The biodegradable fraction of MSW mainly consists of food waste (FW) and corresponds to about 50% of the total MSW. The disposal of FW in the environment has become a significant challenge. On the other hand, FW is an excellent substrate for anaerobic digestion (AD). This manuscript reviews the different AD technologies for the treatment of FW. Different types of bioreactors and pretreatment methods used to enhance methane production through AD of FW are discussed. The current review gives special emphasis on the methods for biogas upgrading and on technologies for FW digestate valorization. Food waste valorization through anaerobic digestion offers a wide variety of options in all process steps. From the pre-treatment of the feedstock and the selection of the suitable anaerobic digestion technology to the configuration of the process based on the desired products and the valorization of the generated digestate, the design of an integrated anaerobic digestion plant is a challenging task, which necessitates a systematic design. A systematic approach is necessary for FW valorization. The simple single-stage AD process leads to underutilization of the feedstock. There are plenty of available technologies that could be combined for the development of an integrated biorefinery that will be optimized in terms of FW valorization towards the production of biofuels and high-added value products, while introducing a circularity in the nutrients contained in the FW. FW-to-biofuel conversion technologies are high Technology Readiness Level (TRL—9) technologies and anaerobic digestion is applied worldwide at commercial scale.

The effects of the combined loading on the bearing capacity (B.C.) shallow bridge foundations on cohesionless soil are investigated by 2D and 3D finite element analyses (F.E.A.), in conjunction with the main parameters involved, as the embedment depth. For the better visual understanding how the various loading or inherent parameters affect the ultimate B.C. the results of F.E.A. are presented as interaction diagrams of the normalized vertical load, moment and horizontal load. The scour effects on the B.C. of shallow foundation are investigated, through the normalized scour depth.

Robotic liver surgery is a novel technique expanding the field of minimally invasive approaches. An increasing number of studies assess the outcomes of robotic liver resections (RLR). The aim of our meta-analysis is to provide an up-to-date comparison of RLR versus open liver resections (OLR), evaluating its safety and efficacy.A systematic search of MEDLINE, Scopus, Google Scholar, Cochrane, and Clinicaltrials.gov for articles published from January 2000 until January 2022 was undertaken.Thirteen non-randomized retrospective and one prospective clinical study enlisting 1801 patients met our inclusion criteria, with 640 patients undergoing RLR and 1161 undergoing OLR. RLR resulted in significantly lower overall morbidity (p0.001), shorter length of hospital stay (p = 0.002), and less intraoperative blood loss (p0.001). Operative time was found to be significantly higher in the RLR group (p0.001). Blood transfusion requirements, R0 resection, and mortality rates presented no difference among the two groups. The cumulative rate of conversion was 5% in the RLR group.The increasing experience in the implementation of the robot will undoubtedly generate more prospective randomized studies, necessary to assess its potential superiority over the traditional open approach, in a variety of hepatic lesions.

Background/aim U-74389G and ascorbic acid protect the cells from oxidation. This study aimed to depict their role in ischemia-reperfusion injury in a renal rat model. Materials and methods Sixty Wistars rats were randomized into six groups of 10 animals each. Group A Ischemia 30 min, reperfusion 60 min; Group B Ischemia 30 min, reperfusion 120 min; Group C Ischemia 30 min, ascorbic acid administration, reperfusion 60 min; Group D Ischemia 30 min, ascorbic acid administration, reperfusion 120 min; Group E Ischemia 30 min, U-74389G administration, reperfusion 60 min; Group F Ischemia 30 min, U-74389G administration, reperfusion 120 min. We then collected tissue and blood samples. Results Histology and the significantly decreased malondialdehyde and tumor necrosis factor-α levels indicated that ascorbic acid was superior to U-74389G, at pre-defined time intervals. Conclusion Ascorbic acid and U-74389G ameliorated renal damage induced by ischemia-reperfusion injury, suggesting a therapeutic effect.

The undrained vertical bearing capacity on a two-layered clay of centrally loaded rigid strip, rectangular and ring footings is studied parametrically with 2D, 3D and axisymmetric finite-element analyses. The shear strength ratio of the two layers and the relative thickness of the uppermost layer with respect to pertinent foundation dimension are the key parameters investigated. In addition, for rectangles and rings the length-to-width (“aspect”) ratio and the ring width to external radius ratio are reported. The results are portrayed in diagrams of bearing capacity and shape modification factors, in the familiar soil mechanics form, along with fitted algebraic expressions to facilitate their numerical use. The failure mechanisms are presented for a number of characteristic cases and are being contrasted with the classical Prandtl failure mechanism, giving additional insight into the mechanics of the problem. The results of the paper can be directly used in practical applications.

The undrained ultimate capacity to combined (M, V) loading of strip and square foundations on a two-layered clay deposit is investigated. Extensive two and threedimensional parametric finite element analyses are carried out in terms of the ratio of the undrained shear strength of two layers, the normalized thickness of the top layer and the normalized load eccentricity. Two basic cases are separately investigated, referring to strength ratios higher or lower than unity. The assumption of effective width of the foundations, to account for eccentricity, generally adopted for homogeneous soil, is extended for two layers. The results are mainly presented in terms of modified bearing capacity factors for strip or square footings for a wide range of dimensionless problem parameters. However, for a better visual understanding of how the bending moment affects the ultimate vertical load failure loci diagrams (“yield surfaces”) in M, V space are also presented. Emphasis is given to developing insight into the particular failure mechanisms of most examined cases.

Natural time analysis enables the introduction of an order parameter for seismicity, which is just the variance of natural time χ, κ1=⟨χ2⟩−⟨χ⟩2. During the last years, there has been significant progress in the natural time analysis of seismicity. Milestones in this progress are the identification of clearly distiguishable minima of the fluctuations of the order parameter κ1 of seismicity both in the regional and global scale, the emergence of an interrelation between the time correlations of the earthquake (EQ) magnitude time series and these minima, and the introduction by Turcotte, Rundle and coworkers of EQ nowcasting. Here, we apply all these recent advances in the global seismicity by employing the Global Centroid Moment Tensor (GCMT) catalog. We show that the combination of the above three milestones may provide useful precursory information for the time of occurrence and epicenter location of strong EQs with M≥8.5 in GCMT. This can be achieved with high statistical significance (p-values of the order of 10−5), while the epicentral areas lie within a region covering only 4% of that investigated.

The scope of this paper is to examine the environmental and economic performance of an alternative household fermentable waste (HFW) management paradigm, developed within the framework of the HORIZON 2020 project Waste4think. In Greece, the business-as-usual scheme for the management of HFW is its disposal in landfills as part of mixed waste. Waste4think developed an alternative approach based on the benefits of source separation. Specifically, source separated HFW is taken to a drying/shredding plant, located in the municipality, for the production of a high-quality biomass product called FORBI. Alternative approaches have been examined for the exploitation of FORBI. In this work, the use of FORBI as an alternative fuel for the cement industry is assessed using life cycle assessment (LCA) and life cycle costing (LCC) tools. The results show that the proposed HFW management framework performs better than the baseline scenario both in economic and environmental terms. However, focus should be given to the optimisation of the drying/shredding process in order to reduce its energy intensity and environmental loadings.

Highlights • During the lockdown: • Two thirds of university students reported at least ‘much’ increase in anxiety • One third in depressive feelings and • 2.59% an increase in suicidal thoughts. • Major depression was present in 12.43% • Severe distress was present in 13.46% • Risk factors were: • Female sex • History of self-injury • History of suicidal attempts • Following studies of law, literature, pedagogics, political sciences and related studies as well as technical but not health sciences • Beliefs in conspiracy theories • Enjoyed acceptance ranging from 20-68% • Students of law, literature, pedagogics, political sciences and related studies manifested higher acceptance rates., Introduction : The aim of the study was to investigate mental health in university students in Greece, during lockdown due to COVID-19. Material and Methods : The data were collected online and anonymously, during lockdown; they included 1104 females (aged 22.08±4,96) and 431 males (aged 22.35±3.11). The analysis included transformation of the data with post-stratification method, descriptive statistics, Chi-square tests, Factorial Analysis of Variance and Relative Risk ratios Results : The results suggest that during, lockdown major depression was present in 12.43% with 13.46% experiencing severe distress. Risk factors were female sex, history of self-injury, suicidal attempts and following theoretical studies (RR=2-5.71). Conspiracy theories were accepted by 20-68%, with students of theoretical studies manifesting higher rates. Discussion : The results of the current study confirmed that students are at high risk to develop depression and suicidality in relation to the COVID-19 outbreak. They also identified specific risk factors and pointed to the role of believing in conspiracy theories in copying with stress. They also identified populations with higher prevalence of these beliefs. Further targeted research is necessary as well as targeted intervention in vulnerable groups but concerning mental health as well as the reduction of believing in conspiracy theories.

The COVID-19 hit also Greece but due to early measures and their exceptional success, the death toll is one of the lowest in the world. Here we report the results from the analysis of the responses to an online survey, from the first 1000 university students, concerning the impact of the lockdown on their mental health. Overall, there was a ‘horizontal’ increase in scores; 42.5% for anxiety, 74.3% for depression, and 63.3% increase in total suicidal thoughts. Quantity of sleep increased in 66.3% but quality worsened in 43.0%. Quality of life worsened in 57.0% (same in 27.9%). There was a 25-3 fold increase in possible clinical cases of depression and an almost 8-fold increase in suicidal thoughts. Almost a third accept and one fifth are open to conspiracy theories concerning COVID-19. To our knowledge this is the first study reporting data concerning the impact of lockdown and quarantine on the mental health of university students. While the acute impact seems clear, the long-term consequences are unknown and although suicidal thoughts have risen substantially, it seems unlikely this will result in deaths. However, the results constitute a clear message that vulnerable populations are at a need for specific interventions concerning their mental health issues.

The present study focuses on the production of an Alternative Fuel (AF) for the cement industry from a Food Residue Biomass (FORBI) product, generated from pre-sorted Household Food Waste (HFW). FORBI is generated by drying and shredding the fermentable fraction of HFW collected door-to-door in the Municipality of Halandri, Greece. The key physicochemical properties such as the net calorific value (NCV), the concentration of heavy metals and chlorine are subsequently determined using well-established international standards (EN and ISO). FORBI is evaluated as a potential AF in terms of technical feasibility and environmental impacts. Based on the characterization, FORBI is classified as a non-dangerous waste according to EWC 20 01 08, European Commission Decision 2014/955. According to EN 15359 it is classified as category 3, 2 and 1 with respect to NCV, Cl and Hg respectively. The study concludes that FORBI is a suitable candidate as a secondary fuel for the cement industry, given its high calorific value along with its low humidity and ash content. Challenges for practical implementation include the relatively high chlorine content, the inclusion of alkalis in the cement produced and the reduction of non-thermal NOx emissions., The data set of the publication can be accessed at: http://doi.org/10.5281/zenodo.3906241

A major factor that determines the mixing pattern inside a reactor is the Residence Time Distribution (RTD). The aim of this paper is the study of the hydraulic behavior of a pilot-scale Periodic Anaerobic Baffled Reactor (PABR) through experimental RTD tests and the development of a CFD model. The tank in series model was used for the determination of the equivalent number (NR) of Continuous Stirred Tank Reactors (CSTR) that simulates the mixing pattern. The hydraulic “dead” space (Vd) was also calculated. Both experimental and simulation results indicate the flexibility of the reactor to perform as a CSTR (NR= 1, Vd= 38.6%–39.6%), as a Plug Flow Reactor (PFR) (NR= 10–16, Vd= 25%–35.4%) or intermediate between the two, depending on the operating parameters. The CFD model can be used for the optimization of the reactor's geometry and for the selection of the optimal operating parameters depending on the type of wastewater to be treated.

The combination of anaerobic digestion and composting is examined as an integrated valorization process of the livestock waste generated in rural areas. Both biogas and high quality compost may be produced by such a combined process. Six different kinds of waste (pig manure, cow manure, cattle manure, poultry manure, sheep manure and whey) were mixed considering the annual waste production of Metsovo region, Greece, in a representative way. The feed was subjected to a solids/liquid separation step. The bioreactor was operated in different phases with different organic loadings of the liquid fraction of the waste. During phase #1, the Periodic Anaerobic Baffled Reactor (PABR) was fed with a hydraulic retention time (HRT) of 10.65 days, (an organic loading rate of 0.83 g-COD Lreactor−1 day−1) and the biogas production rate was 0.2 Lbiogas Lreactor−1 day−1. During phase #2, the organic loading rate was increased to 1.9 g-COD Lreactor−1 day−1. The biogas production rate was 0.41 Lbiogas Lreactor−1 day−1. During phase #3, the organic loading rate was increased to 2.69 g-COD Lreactor−1 day−1 by decreasing the HRT to 6 days, resulting in the kinetic limitation of the process. The biogas production rate increased to 0.68 Lbiogas Lreactor−1 day−1 with an average methane composition of 65%. The experimental results obtained were used as a basis for the development of an ADM1 model (Batstone et al. in Anaerobic digestion model no. 1 (ADM1). IWA Task Group for Mathematical Modelling of Anaerobic Digestion Processes Report no 1, vol 1(1), 2002) that was able to adequately simulate the operation of the bioreactor. The solid fraction of the pretreatment step was mixed with sawdust and fed to a closed-vessel composter. The highest temperature (56.2 °C) was reached in 2 days. The germination index (GI) of the compost produced was 77.8%, meaning that it was free of phytotoxic substances.

The objective of this work is the evaluation of two alternative ways of valorizing the liquid fraction of a mixture of different kinds of livestock waste and cheese whey, namely (a) biogas production through the anaerobic co-digestion of in a Periodic Anaerobic Baffled Reactor (PABR) and (b) electrical energy generation in a Microbial Fuel Cell (MFC). The different kinds of livestock manure (pig manure, cow manure, poultry manure, sheep manure and cheese whey) were collected from the region of Metsovo, Greece. The mixture was passed through a pretreatment process producing a liquid fraction that was treated (a) in a pilot-scale Periodic Anaerobic Baffled Reactor (PABR) for methane production and (b) in a lab-scale two-chamber Microbial Fuel Cell for electricity production. In the present study, the experimental data obtained from a previous study [1] were used for the evaluation of a simple mathematical model, based on Monod kinetics, for the PABR using Aquasim 2.1 [2]. The simple model was able to satisfactorily describe the behavior of the PABR in terms of soluble COD consumption. In addition, the same liquid waste, filtered (0.70 μm) and diluted at different initial concentrations, was used as feedstock for electricity production, using a two-chamber microbial fuel cell (MFC). The experiments showed that the MFC performance was not limited by the wastewater strength, since the substrate removal efficiency and the maximum power density were not affected by an increase of the initial concentration. The required time showed a linear relationship with the initial concentration of the substrate.

The aim of this chapter is to provide a description of the main methods used to assess biological transformation of biomass. It will address saccharification tests which account for the ability of biomass to release sugars during enzymatic hydrolysis. Biochemical methane potential (BMP) tests, which are widely used to assess anaerobic digestibility of biomass for the production of methane and BMP prediction by near infra-red spectroscopy will be presented. Biohydrogen potential (BHP), used to assess the ability to produce biohydrogen from biomass by dark fermentation will be described. Respirometry tests accounting for assessing aerobic degradability of biomass will be described. Incubation tests used to assess carbon and nitrogen degradation in soils will also be presented.

The genus Strychnos (Loganiaceae) is well-known as a rich source of various bioactive metabolites. In continuation of our phytochemical studies on plants from Amazonia, we examined Strychnos aff. darienensis, collected in Peru. This species has been traditionally used in South America and is still presently used as a drug by the Yanesha tribe in Peru. Phytochemical investigation of this plant led to the isolation and structure elucidation by NuclearMagnetic Resonance and High Resolution Mass Spectroscopy of 14 compounds that belong to the categories of phenolic acids [p-hydroxybenzoic acid (1) and vanillic acid (2)], flavonoids [luteolin, (3),3-O-methyl quercetin (4), strychnobiflavone (5), minaxin (6) and 3’,4’,7-trihydroxy-flavone (7)], lignans [syringaresinol-beta-D-glucoside (8), balanophonin (9) and ficusal (10)] and alkaloids [venoterpine (11), 11-methoxyhenningsamine (12), diaboline (13) and 11-methoxy diaboline (14)]. The isolated flavonoids-a class known for its anti-aging activities-were further evaluated for their biological activities on normal human skin fibroblasts. Among them, only (6), and to a lesser extent (7), exhibited cytotoxicity at 100 mu g/ml. All five flavonoids suppressed intracellularreactive oxygen species (ROS) levels, either basal or following stimulation with hydrogen peroxide or both. Moreover, luteolin and strychnobiflavone protected skin fibroblasts against ultraviolet (UV)-irradiation-induced cell death. The isolated flavonoids could prove useful bioactive ingredients in the cosmetic industry.

This study concerns the production of hydrogen and methane from a Food Residue Biomass (FORBI) product (Papanikola et al. in 5th international conference on sustainable waste management systems, Athens, 2017), generated from pre-sorted HFW in a CSTR and in a PABR respectively. FORBI is generated by drying and shredding the fermentable fraction of household food waste collected door-to-door in the Municipality of Halandri, Greece. Hydrogen production from FORBI through anaerobic fermentation under acidogenic mesophilic conditions was carried out using a 4 L CSTR, operated at 12 h HRT under an organic loading of 15 g TS L−1. The H2-CSTR was operated for 40 days. During the operation of H2-CSTR the production of biogas reached up to 0.1026 Lbiogas gFORBI−1 and the percentage of hydrogen in the gas up to 48.2%. The conversion of FORBI into methane was carried out through the operation of a 77 L PABR operated under mesophilic methanogenic conditions at various operating parameters (OLR, HRT, T). Two different approaches were adopted for the pre-treatment of the feedstock. For the two first phases of the experimental procedure, a liquid extraction step was carried out before feeding the bioreactor with the separated liquid fraction, while in the subsequent three phases, a whole suspension of FORBI was used as feed. The mean biogas production rate was 0.158 ± 0.02 Lbiogas gFORBI−1 and the mean methane percentage in the biogas was 67.5 ± 2.1%, in the first two phases. The mean biogas production rate was 0.519 ± 0.03 Lbiogas gFORBI−1 and the mean methane percentage in the biogas was 66 ± 2.8%, when a whole suspension of FORBI was fed to the PABR.

This article explains the Halandri pilot in the Wsate4think project: An alternative management of biowaste for biomass production

Some basic factors which influence the behaviour of the anchored retaining structures are investigated and 2D analyses with three dimensional ones are compared. The parametric analysis under 2D conditions focuses on the influence of significant factors such as the normalized embedded depth of the wall, the resistance of the anchors, the free tendon length, the earth pressure coefficient at rest and the flexibility of the system, on the behaviour of the retaining structure. The analyses are performed in two groups for two representative soil types named S1 (weathered weak rock) and S2 (very stiff clay). Qualitative as well as quantitative conclusions are derived from the analyses concerning the influence of the above mentioned factors, mainly on the safety factor as well as on the displacements. The 3D analyses are carried out for various ratios L/H, where L is the length and H the height of the slope. Several trends are confirmed from the results concerning the influence of the above-mentioned factors. It is concluded that the triaxal conditions strongly affect the safety factor, as well as the distribution of horizontal and vertical displacements, mainly in the cases where the ratios L/H ≤ 2. Some serious deviations between 2D and 3D analyses are pointed out and the physical explanation of these differences is given for several cases.

Aim Lignocellulosic biomass, mostly by agricultural and forestry sources, mainly consists of cellulose, hemicelluloses, and lignin. White rot fungi are known to be efficient degraders of cellulose due to their ligninolytic enzyme system. The use of Pleurotus ostreatus AMRL 141 as a biological treatment of wheat straw (WS) was explored to determine the most significant variables affecting the cultivation of fungus. Methods Two experimental designs were applied: firstly, a 2-level factorial design (screening) with 7 variables and 3 responses and a central composite design with 4 variables and 3 responses. The optima of the statistically adequate models obtained for a 2 weeks cultivation period were then found. The solid state medium used was sandy soil mixed with agricultural residue (milled WS). Results Overall, the results of many previous studies of our research group have proved that Pleurotus ostreatus is an efficient lignocellulosic decomposer. In this study, design of experiments methodologies were successfully used and the optimum values of responses found for the two weeks cultivation period were lag time (2 days), extent of colonization (46 mm), and propagation velocity (3 mm d−1). © 2015 American Institute of Chemical Engineers Environ Prog, 2015

In this study, the use of a dual-chamber microbial fuel cell for the production of bioelectricity from a food residue biomass (FORBI) product was investigated. Food residue biomass was produced by drying and shredding the pre-sorted fermentable fraction of household food waste collected door-to-door in the Municipality of Halandri, Athens, Greece. Different organic loads of food residue biomass expressed as chemical oxygen demand (COD) were examined (0.7, 0.9, 1.4, 2.8, 6 and 14 g COD L−1, respectively). It was observed that an increase of the initial concentration of the final extract resulted in a corresponding increase in the operating time. The microbial fuel cell potential increased from 33.3 mV to 46 mV as the concentration was increased from 0.7 to 14 g COD L−1. The best performance in terms of maximum power density (29.6 mW m−2) corresponding to a current density of 88 mA m−2 was observed for 6 g COD L−1. Setting the external resistance at its optimal value (Rext = 2 kΩ) as determined by polarisation experiments, Pyield drastically increased to 13.7 and 17.3 Joule (g FORBI)−1 in two consecutive cycles. The results demonstrate that readily biodegradable substrates, such as food residue biomass, can be effectively used for enhanced bioelectricity harvesting in a microbial fuel cell.

Within the framework of a research program on the behaviour of a specific type of screw micropile with helical plates of 220 mm diameter, the response in axial and horizontal loadings by the finite element method and full scale in situ tests were investigated. For the axial compressive or tensile loads, the simulation of the helical plates was carried out under axisymmetric conditions as shell foundations. The cases of purely cohesive or cohesionless soils with linear elastic–perfectly plastic behaviour were studied. The influence of shear strength parameters and the number of helical plates on the characteristic-ultimate resistance were also analyzed. For the horizontal loads 3D F.E. programs were applied for the analyses of the micropiles either as short or long ones. The in situ tests, which are presented in this article, were performed in two areas with representative subsoil conditions. The respective predictions from the F.E. method were based on results of geotechnical investigations and compared with the results of the in situ tests. A good approximation was ascertained, especially for uplift and horizontal loads and the differences were commented.

Dyes released by the textile industries pose a threat to environmental quality. Ligninolytic white-rot fungi can effectively decolorize colored effluents and conventional dyes. The present study investigates the ability of eleven strains belonging to Pleurotus, Ganoderma and Lentinula mushroom genera in the decolorization of eight textile azo and anthraquinone dyes added in solid-plate cultures. Pleurotus pulmonarius AMRL 177, showing the greatest decolorization ability, was further investigated for Remazol Brilliant Blue R (RBBR) decolorization using response surface methodology (RSM). RSM involved Box-Behnken design matrix for three design factors: dye concentration, nitrogen concentration and copper concentration were successfully employed for the optimization of four responses: lag time, mycelium extension rate, decolorization rate and laccase activity. Optimum values of responses obtained were: lag time 3 days, mycelium extension rate 2.8 mm d−1, decolorization rate 2.7 mm d−1 and laccase activity 480 U ml−1.

A commercial strain of the fungus Pleurotus ostreatus was used to mediate the degradation of lindane, by landfarming technology during a 4 weeks statistical experiment. The Multilevel Factorial Design was used with two design factors, namely, straw content X 1 (%) and lindane content X 2 (ppm). The optimization parameters (responses) investigated were: biodegradation rate Y 1 (μg d−1), biomass growth rate Y 2 (mg d−1), biodegradation/biomass Y 3 (μg mg−1), total organic carbon Y 4 (%), total organic nitrogen Y 5 (%) and total organic carbon/total organic nitrogen Y 6. The optima of the adequate models obtained for the period of 2 and 4-weeks were found. An overall kinetic study, conducted in this work with the aid of experimental design, determined the optimum (maximum) specific lindane degradation rate to be 0.16 g kg−1 month−1.

Nowadays, cultural development is considered to be a matter of high priority for a modern state. Local cultural assets play a major role in the design and development of a successful and sustainable national cultural development policy. The purpose of the current survey is to explore to what extend people who are residents at the Municipality of Serres realize the importance of cultural assets in the context both of national or regional economic development and which are these local cultural assets and resources. Additionally, the survey presented, attempts to gain insight into what are the factors that inhibit local cultural development and which are the main driving instructions responsible for the exploitation of these cultural assets and resources. In order to achieve its goals, the survey utilizes a sample of 121 responses to a comprehensive questionnaire, answered mainly by people who are permanent residents at the greater area of the Municipality of Serres. Analysis of the results gave strong evidence that the Municipality of Serres hosts and important number of cultural resources, which are not yet sufficiently exploited and promoted. In addition, citizens realize the important role cultural development can play in local economy and the value it can add in order to advance local economy as a whole.

The degradation of lindane was studied in liquid-agitated cultures using a commercial strain of the fungus Pleurotus ostreatus as the biodegrading organism. The biodegradation was accomplished with the action of extracellular oxidative enzymes, produced by the fungus to decompose woody substrates. Enzyme activities of manganese peroxidase and laccase were measured in a liquid mineral medium. An orthogonal Central Composite Design of experiments was used to construct second-order response surfaces with the fungus growth, final pH and the lindane biodegradation as optimization parameters. The initial lindane concentration, the nitrogen content, the incubation time and the temperature were used as design factors. Optimal conditions found for all these parameters will be used for the continuation of this project aiming at the bioremediation of contaminated sites with persistent organic pollutants such as lindane. Keywords: Bioremediation, Lindane, Fungi, Biodegradation, Ligninolytic enzymes, Response surface methodology, Central composite design

The aim of the study was to assess treatment effects and potential side effects of different archwires used on patients receiving orthodontic therapy. Electronic and manual unrestricted searches were conducted in 19 databases including MEDLINE, Cochrane Library, and Google Scholar until April 2012 to identify randomized controlled trials (RCTs) and quasi-RCTs. After duplicate study selection, data extraction, risk of bias assessment with the Cochrane risk of bias tool, and narrative analysis, mean differences (MDs) with confidence intervals (CIs) of similar studies were pooled using a random-effects model and evaluated with GRADE. A total of 16 RCTs were included assessing different archwire characteristics on 1108 patients. Regarding initial archwires, meta-analysis of two trials found slightly greater irregularity correction with an austenitic-active nickel-titanium (NiTi) compared with an martensitic-stabilized NiTi archwire (corresponding to MD: 1.11 mm, 95% CI: -0.38 to 2.61). Regarding archwire sequences, meta-analysis of two trials found it took patient treated with a sequence of martensitic-active copper-nickel-titanium (CuNiTi) slightly longer to reach the working archwire (MD: 0.54 months, 95% CI: -0.87 to 1.95) compared with a martensitic-stabilized NiTi sequence. However, patients treated with a sequence of martensitic-active CuNiTi archwires reported general greater pain intensity on the Likert scale 4 h and 1 day after placement of each archwire, compared with a martensitic-stabilized NiTi sequence. Although confidence in effect estimates ranged from moderate to high, meta-analyses could be performed only for limited comparisons, while inconsistency might pose a threat to some of them. At this point, there is insufficient data to make recommendations about the majority of initial archwires or for a specific archwire sequence.

SUMMARY BACKGROUND: Fixed-appliance treatment is a major part of orthodontic treatment, but clinical evidence remains scarce. OBJECTIvES: Objective of this systematic review was to investigate how the therapeutic effects and sideeffects of brackets used during the fixed-appliance orthodontic treatment are affected by their characteristics. SEARCh METhODS AND SElECTION CRITERIA: We searched MEDlINE and 18 other databases through April 2012 without restrictions for randomized controlled trials and quasi-randomized controlled trials investigating any bracket characteristic. DATA COllECTION AND ANAlYSIS: After duplicate selection and extraction procedures, risk of bias was assessed also in duplicate according to Cochrane guidelines and quality of evidence according to the Grades of Recommendation. Assessment, Development and Evaluation approach. Random-effects meta-analyses, subgroup analyses, and sensitivity analyses were performed with the corresponding 95 per cent confidence intervals (CI) and 95 per cent prediction intervals (PI). RESUlTS: We included 25 trials on 1321 patients, with most comparing self-ligated (S l) and conventional brackets. Based on the meta-analyses, the duration of orthodontic treatment was on average 2.01 months longer among patients with S l brackets (95 per cent CI: 0.45 to 3.57). The 95 per cent PIs for a future trial indicated that the difference could be considerable (−1.46 to 5.47 months). Treatment characteristics, outcomes, and side-effects were clinically similar between S l and conventional brackets. For most bracket characteristics, evidence is insufficient. Some meta-analyses included trials with high risk of bias, but sensitivity analyses indicated robustness. CONClUSIONS: Based on existing evidence, no clinical recommendation can be made regarding the bracket material or different ligation modules. For S l brackets, no conclusive benefits could be proven, while their use was associated with longer treatment durations.

SUMMARY The analysis of the non-linear and time-dependent viscoelasticity of the periodontal ligament (PDL) enables a better understanding of the biomechanical features of the key regulator tissue for tooth movement. This is of great significance in the field of orthodontics as targeted tooth movement remains still one of the main goals to accomplish. The investigation of biomechanical aspects of the PDL function, a difficult area of research, helps towards this direction. After analysing the time-dependent biomechanical properties of pig PDL specimens in an in vitro experimental study, it was possible to confirm that PDL has a viscoelastic anisotropic behaviour. Three-dimensional finite element models of mini-pig mandibular premolars with surrounding tissues were developed, based on micro-computed tomography (μCT) data of the experimental specimens. Tooth mobility was numerically analysed under the same force systems as used in the experiment. A bilinear material parameter set was assumed to simulate tooth displacements. The numerical force/displacement curves were fitted to the experimental curves by repeatedly calculating tooth displacements of 0.2mm varying the loading velocities and the parameters, which describe the nonlinearity. The experimental results showed a good agreement with the numerical calculations. Mean values of Young's moduli E1, E2 and ultimate strain ε12 were derived for the elastic behaviour of the PDL for all loading velocities. E1 and E2 values increased with increasing the velocity, while ε12 remained relatively stable. A bilinear approximation of material properties of the PDL is a suitable description of measured force/displacement diagrams. The numerical results can be used to describe mechanical processes, especially stress-strain distributions in the PDL, accurately. Further development of suitable modelling assumptions for the response of PDL under load would be instrumental to orthodontists and engineers for designing more predictable orthodontic force systems and appliances

The aim of the present work was to evaluate the biomechanical behaviour of the periodontal ligament (PDL) with respect to force development with different controlled loading velocities. For this purpose, an in vitro experimental study was performed on 18 minipig jaw segments. Displacements with variable increasing loading time were applied to one premolar crown of each jaw segment into the linguobuccal direction through a force sensor provided by a specialized biomechanical set-up. The predefined displacement values to be achieved were 0.1 and 0.2 mm. Each of the given displacement increments was applied on the specimens with a linear displacement increase employing the following time spans: 5, 10, 20, 30, 60, 120, 300, 450, and 600 seconds. Force values were measured during load application to register force/displacement diagrams and after the maximum displacement was reached force decay was monitored for a period of 600 seconds. Force/time curves for each tooth were plotted according to the data obtained. Diagrams of the maximum force values obtained from these plots and the force at the end of each measurement were extracted for all teeth. Forces at the point when maximum displacement was reached ranged from 0.5 to 2.5 N for the 0.1 mm activation and showed extreme variation with the specimens. The factor of volume and surface area of the individual roots were evaluated and found not to be responsible for these deviations. A comparable behaviour was recorded for the 0.2 mm deflection, however, on a higher force level. The results show that the force development at different displacement velocities is complex and dominated by the PDL biomechanical characteristics.

Mycelium growth rates, biomass concentration (estimated as glucosamine content) and laccase and endoglucanase secretion were monitored during solid state fermentation (SSF) of wheat straw (WS), reed grass (RG) and bean stalk (BS) residues by Lentinula edodes strains 119, 121, and 122. In a first experiment, these strains were subjected to screening regarding their growth rates and biomass yield, where strain 121 proved to be the fastest colonizer. However, the greater biomass yield at the end of colonization was demonstrated by strain 122 on BS (465.93 mg g(-1) d.w.). In a second experiment, growth characters, as well as endoglucanase and laccase production patterns of the selected strains 121 and 122 were monitored at three intervals i.e., at 33, 66, and 100% of substrate colonization. BS furnished the highest endoglucanase production for strain 121, while RG for strain 122. A strain and substrate-dependent behaviour of the enzyme secretion was detected, with strain 122 presenting maximal endoglucanase activity in all substrates at the initial (33%) and final (100%) stages of colonization (0.64-0.90 and 0.79-0.97 U g(-1,) respectively). However, in strain 121 the peak of endoglucanase production was detected in the early stages of colonization (at 33% on WS and at 66% on RG and BS). Laccase activity showed increased values (maxima on WS, 353.68 and 548.67 U g(-1) by strains 121 and 122, respectively) at 66% of colonization. Correlation analysis of growth data demonstrated negative relations between growth rate and biomass yield and between laccase and endoglucanase activities on WS and RG substrates fermented by strain 122. Finally, possible relations of growth parameters with nutritional constituents of the substrates were investigated.

To summarise the currently available evidence on the effects of microorganisms on the corrosion processes of biomaterials, with specific relevance to orthodontic alloys.Factors related to the micro-environmental milieu, conditions, site characteristics, microbial species, enzymes and compounds released in response to their attachment to surfaces and formation of biofilms are analysed with respect to their contributory roles in corrosion.Application to orthodontics is projected from relevant evidence, albeit hypothetical due to the lack of extensive investigations of the subject. The micro-organisms involved and effects observed in orthodontic alloys are summarised. Finally, protective measures are proposed to minimise the potential for corrosion processes in orthodontic patients.