Infections are one of the main reasons for removal of implants from patients, and usually need difficult and expensive treatments. Staphylococcus aureus and Staphylococcus epidermidis are the most ...frequently detected pathogens. We reviewed the epidemiology and pathogenesis of implant-related infections. Relevant studies were identified by electronic searching of the following databases: PubMed, ScienceDirect, Academic Google, and CAPES Journal Portal. This review reports epidemiological studies of implant infections caused by S. aureus and S. epidermidis. We discuss some methodologies used in the search for new compounds with antibiofilm activity and the main strategies for biomaterial surface modifications to avoid bacterial plaque formation and consequent infection. S. aureus and S. epidermidis are frequently involved in infections in catheters and orthopaedic/breast implants. Different methodologies have been used to test the potential antibiofilm properties of compounds; for example, crystal violet dye is widely used for in-vitro biofilm quantification due to its low cost and good reproducibility. Changes in the surface biomaterials are necessary to prevent biofilm formation. Some studies have investigated the immobilization of antibiotics on the surfaces of materials used in implants. Other approaches have been used as a way to avoid the spread of bacterial resistance to antimicrobials, such as the functionalization of these surfaces with silver and natural compounds, as well as the electrical treatment of these substrates.
While climate change is a global phenomenon, its negative impacts are more severely felt in poor countries because of their high dependence on natural resources and limited coping capacity to climate ...variability and extremes. However, investigation of the relationship between poverty, climate variability and water-related disasters is complex. This article investigates the relationship between disaster risk, poverty, and the associated vulnerability of households and communities. The case study on which the article is based was carried out in Sri Lanka, a developing country prone to disasters. Data collected from household surveys conducted in North Central province, Sri Lanka, was examined with the use of cross tabulation and regression analysis techniques. Our study is novel because it considers floods and droughts together and compares their economic impact on socioeconomic groups at a local level.
Our findings show that households depend heavily on natural resources for their livelihood, and that those with low income suffer greater losses from floods and droughts than households with high income. On the other hand flood impact is higher on households depend heavily on natural resources for their livelihood, and having lower income. The study uses survey data to examine the relationship between disaster frequency and localized poverty, an issue rarely considered in past literature. We show that low income households that depend fully on natural resources for their livelihood are exposed to more frequent disasters and most vulnerable to financial losses incurred through floods and droughts. To combat the effects of disasters, the Sri Lankan government might encourage members of poor households to seek at least some income from non-agricultural endeavors.
Ethyl lactate is an environmentally benign solvent with effectiveness comparable to petroleum-based solvents. The worldwide solvent market is about 30 million pounds per year, where ethyl lactate can ...have an important share. It is considered a chemical commodity and has attracted much attention in recent years, since it is formed by the esterification reaction of ethanol and lactic acid, which can be generated from biomass raw materials through fermentation. In this work, an overview regarding the main properties and applications of ethyl lactate, as well as its synthesis and production processes, with a particular emphasis on reactive/separation processes, is presented.
Environmental pollution is a recognized issue of major concern since a wide range of contaminants has been found in aquatic environment at ngL−1 to μgL−1 levels. In the year 2000, a strategy was ...defined to identify the priority substances concerning aquatic ecosystems, followed by the definition of environmental quality standards (EQS) in 2008. Recently it was launched the Directive 2013/39/EU that updates the water framework policy highlighting the need to develop new water treatment technologies to deal with such problem. This review summarizes the data published in the last decade regarding the application of advanced oxidation processes (AOPs) to treat priority compounds and certain other pollutants defined in this Directive, excluding the inorganic species (cadmium, lead, mercury, nickel and their derivatives).
The Directive 2013/39/EU includes several pesticides (aldrin, dichlorodiphenyltrichloroethane, dicofol, dieldrin, endrin, endosulfan, isodrin, heptachlor, lindane, pentachlorophenol, chlorpyrifos, chlorfenvinphos, dichlorvos, atrazine, simazine, terbutryn, diuron, isoproturon, trifluralin, cypermethrin, alachlor), solvents (dichloromethane, dichloroethane, trichloromethane and carbon tetrachloride), perfluorooctane sulfonic acid and its derivatives (PFOS), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), nonylphenol and octylphenol, as well as the three compounds included in the recommendation for the first watch list of substances (diclofenac, 17-alpha-ethinylestradiol (EE2) and 17-beta-estradiol (E2)). Some particular pesticides (aclonifen, bifenox, cybutryne, quinoxyfen), organotin compounds (tributyltin), dioxins and dioxin-like compounds, brominated diphenylethers, hexabromocyclododecanes and di(2-ethylhexyl)phthalate are also defined in this Directive, but studies dealing with AOPs are missing.
AOPs are recognized tools to destroy recalcitrant compounds or, at least, to transform them into biodegradable species. Diuron (a phenylurea herbicide) and atrazine (from the triazine chemical class) are the most studied pesticides from Directive 2013/39/EU. Fenton-based processes are the most frequently applied to treat priority compounds in water and their efficiency typically increases with the operating temperature as well as under UV or solar light. Heterogeneous photocatalysis is the second most used treatment to destroy pollutants defined in the Directive. Ozone alone promotes the partial oxidation of pollutants, and an increase in the effluent biodegradability, but complete mineralization of pollutants is difficult. To overcome this drawback, ozonation has been combined with heterogeneous catalysts, addition of H2O2, other AOPs (such as photocatalysis) or membrane technologies.
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•AOPs to treat priority compounds listed in the Directive 2013/39/EU are reviewed.•Fenton-based processes, photocatalysis and ozonation are the most frequently applied.•Importance of AOPs to treat recalcitrant compounds is emphasized.
Polyvinylidene fluoride (PVDF) flat sheet membranes were blended with multi-walled carbon nanotubes (MWCNTs) by the phase inversion method for direct contact membrane distillation (DCMD) of salty ...water (35gL−1 NaCl). The membrane properties and performances depended markedly on the synthesis parameters such as MWCNT loading, polyvinylpyrrolidone (PVP) addition and MWCNT surface chemistry. MWCNT/PVDF membranes prepared with functionalized MWCNTs have a smaller pore size (determined by bubble point measurements) and lower contact angles, thus, functionalization of MWCNTs is not recommended for this application. For membranes presenting the same pore size, the pore morphology and the membrane thickness are crucial for efficient salt rejection. Sponge-like pores and the smallest possible thickness (i.e., membranes prepared without PVP) allow complete salt rejection (i.e., 100%), in contrast with larger thickness and elongated finger-like pores (resulting from PVP addition) whose salt exclusion ranged from 88.8 to 98.6%. Overall, the MWCNT/PVDF blended membrane prepared with 0.2wt.% optimal content of pristine MWCNTs (without adding PVP) exhibited the best performance in DCMD, presenting total salt rejection and a higher permeate flux (9.5×10−3kgm−2s−1) than that obtained with a commercial PVDF membrane (7.8×10−3kgm−2s−1).
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•MWCNT/PVDF blended membranes prepared by phase inversion method•Membranes tested in direct contact membrane distillation (DCMD) of salty water•Large sponge-like pores and small membrane thickness allow complete salt rejection.•Functionalization of MWCNTs and PVP addition are not recommended.•The membrane with 0.2wt.% of pristine MWCNTs exhibited the best performance.
Aim
The maternal environment during pregnancy and lactation plays a determining role in programming energy metabolism in offspring. Among a myriad of maternal factors, disruptions in the light/dark ...cycle during pregnancy can program glucose intolerance in offspring. Out‐of‐phase feeding has recently been reported to influence metabolism in adult humans and rodents; however, it is not known whether this environmental factor impacts offspring metabolism when applied during pregnancy and lactation. This study aims to determine whether maternal day‐restricted feeding (DF) influences energy metabolism in offspring.
Methods
Pregnant and lactating Wistar rats were subjected to ad libitum (AL) or DF during pregnancy and lactation. The offspring born to the AL and DF dams were intra‐ and interfostered, which resulted in 4 group types.
Results
The male offspring born to and breastfed by the DF dams (DF/DF off) were glucose intolerant, but without parallel insulin resistance as adults. Experiments with isolated pancreatic islets demonstrated that the male DF/DF off rats had reduced insulin secretion with no parallel disruption in calcium handling. However, this reduction in insulin secretion was accompanied by increased miRNA‐29a and miRNA34a expression and decreased syntaxin 1a protein levels.
Conclusion
We conclude that out‐of‐phase feeding during pregnancy and lactation can lead to glucose intolerance in male offspring, which is caused by a disruption in insulin secretion capacity. This metabolic programming is possibly caused by mechanisms dependent on miRNA modulation of syntaxin 1a.
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The biocatalytic performance of immobilized enzyme systems depends mostly on the intrinsic properties of both biomolecule and support, immobilization technique and immobilization ...conditions. Multi-walled carbon nanotubes (MWCNTs) possess unique features for enzyme immobilization by adsorption. Enhanced catalytic activity and stability can be achieved by optimization of the immobilization conditions and by investigating the effect of operational parameters.
Laccase was immobilized over MWCNTs by adsorption. The hybrid material was characterized by Fourier transformed infrared (FTIR) spectroscopy, scanning and transmission electron microscopy (SEM and TEM, respectively). The effect of different operational conditions (contact time, enzyme concentration and pH) on laccase immobilization was investigated. Optimized conditions were used for thermal stability, kinetic, and storage and operational stability studies.
The optimal immobilization conditions for a laccase concentration of 3.75μL/mL were a pH of 9.0 and a contact time of 30min (522 Ulac/gcarrier). A decrease in the thermal stability of laccase was observed after immobilization. Changes in ΔS and ΔH of deactivation were found for the immobilized enzyme. The Michaelis–Menten kinetic constant was higher for laccase/MWCNT system than for free laccase. Immobilized laccase maintained (or even increased) its catalytic performance up to nine cycles of utilization and revealed long-term storage stability.
Design of graphene-based TiO2 photocatalysts—a review Morales-Torres, Sergio; Pastrana-Martínez, Luisa M.; Figueiredo, José L. ...
Environmental science and pollution research international,
11/2012, Letnik:
19, Številka:
9
Journal Article
Recenzirano
There is a recent increase in the interest of designing high-performance photocatalysts using graphene-based materials. This review gathers some important aspects of graphene–TiO
2
, graphene ...oxide–TiO
2
, and reduced graphene oxide–TiO
2
composites, which are of especial relevance as next generation photocatalysts. The methods used for the preparation of these materials, the associated mechanistic fundamentals, and the application of graphene-based composites on the photocatalytic degradation of pollutants are reviewed. Some structural, textural, and chemical properties of these materials and other photo-assisted applications, such as hydrogen production from water splitting and dye-sensitized solar cells, are also briefly included.
Photocatalytic ozonation was employed for the first time in continuous mode with TiO2-coated glass Raschig rings and light emitting diodes (LEDs) to treat urban wastewater as well as surface water ...collected from the supply area of a drinking water treatment plant (DWTP). Different levels of contamination and types of contaminants were considered in this work, including chemical priority substances (PSs) and contaminants of emerging concern (CECs), as well as potential human opportunistic antibiotic resistant bacteria and their genes (ARB&ARG). Photocatalytic ozonation was more effective than single ozonation (or even than TiO2 catalytic ozonation) in the degradation of typical reaction by-products (such as oxalic acid), and more effective than photocatalysis to remove the parent micropollutants determined in urban wastewater. In fact, only fluoxetine, clarithromycin, erythromycin and 17-alpha-ethinylestradiol (EE2) were detected after photocatalytic ozonation, by using solid-phase extraction (SPE) pre-concentration and LC-MS/MS analysis. In surface water, this treatment allowed the removal of all determined micropollutants to levels below the limit of detection (0.01–0.20 ng L−1). The efficiency of this process was then assessed based on the capacity to remove different groups of cultivable microorganisms and housekeeping (16S rRNA) and antibiotic resistance or related genes (intI1, blaTEM, qnrS, sul1). Photocatalytic ozonation was observed to efficiently remove microorganisms and ARGs. Although after storage total heterotrophic and ARB (to ciprofloxacin, gentamicin, meropenem), fungi, and the genes 16S rRNA and intI1, increased to values close to the pre-treatment levels, the ARGs (blaTEM, qnrS and sul1) were reduced to levels below/close to the quantification limit even after 3-days storage of treated surface water or wastewater. Yeast estrogen screen (YES), thiazolyl blue tetrazolium reduction (MTT) and lactate dehydrogenase (LDH) assays were also performed before and after photocatalytic ozonation to evaluate the potential estrogenic activity, the cellular metabolic activity and the cell viability. Compounds with estrogenic effects and significant differences concerning cell viability were not observed in any case. A slight cytotoxicity was only detected for Caco-2 and hCMEC/D3 cell lines after treatment of the urban wastewater, but not for L929 fibroblasts.
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•Treatment of urban wastewater and of surface water for drinking water production.•Removal efficiency assessment of antibiotic resistant bacteria (ARB) & genes (ARGs).•Photocatalytic ozonation in continuous mode with TiO2-coated glass rings and LEDs.•Efficient removal of organic micropollutants, cultivable microorganisms and ARGs.•ARGs below/close to quantification limit even after 3-days storage of treated water.
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