Steroid estrogen determination in sediment and sewage sludge: A critique of chromatographic / mass spectrometry methods incorporating a case study in method development

Current analytical methods for determining steroids in sewage sludge and sediment are reviewed and experimental data comparing LC/MS ESI and GC/MS quantification of extracts from these matrices is presented. The effect of matrix influence on method analysis and steroid recoveries was investigated and a comparison of GC and LC determination with mass spectrometry performed. Consequently upon this, an environmental analytically robust methodology is presented and using this technique analysis of sediments determined E1 to be the main steroid (<18 ng/g), EE2 and E3 were determined at far lower concentrations with minimal detection of E

An assessment of the bioaccumulation of estrone in Daphnia magna

The bioaccumulation of estrone by Daphnia magna was determined. Direct uptake via the aqueous medium occurred within the first 16 hours. A bioconcentration factor of 228 was established over all temporal periods. Ingestion via Chlorella vulgaris gave a partitioning factor of 24 which may approximate to a biomagnification factor assuming steady state conditions. These preliminary results indicate that the partitioning to Daphnia magna via the food source, Chorella vulgaris is less significant than bioconcentration

Harnessing magnetic-mechano actuation in regenerative medicine and tissue engineering

Mechanical stimulus is of upmost importance in tissues developmental and regeneration processes as well as in maintaining body homeostasis. Classical physiological reactions encompass an increase of blood vessel diameter upon exposure to high blood pressure, or the expansion of cortical bone after continuous high-impact exercise. At a cellular level, it is well established that extracellular stiffness, topography, and remote magnetic actuation are instructive mechanical signals for stem cell differentiation. Based on this, biomaterials and their properties can be designed to act as true stem cell regulators, eventually leading to important advances in conventional tissue engineering techniques. This review identifies the latest advances and tremendous potential of magnetic actuation within the scope of regenerative medicine and tissue engineering

Platelet lysate-loaded photocrosslinkable hyaluronic acid hydrogels for periodontal endogenous regenerative technology

The integrity and function of the periodontium can be compromised by traumatic injuries or periodontitis. Currently available clinical therapies are able to stop the progression of periodontitis and allow the healing of periodontal tissue. However an optimal strategy capable of restoring the anatomy and functionality of the lost periodontal tissue is still to be achieved. Herein is proposed the development of an injectable hydrogel system able to release a growth factors and cells to the periodontal defect. This injectable system is based on a photocrosslinkable hydrogel, prepared from methacrylated Hyaluronic Acid (me-HA) and incorporating Platelet Lysate (PL). The delivery of growth factors and cells in situ is expected to enhance regeneration of the periodontium. Various formulations of me-HA containing increasing PL concentrations were studied for achieving the formation of stable photocrosslinkable hydrogels. The produced hydrogels were subsequently characterized to assess mechanical properties, degradation, protein/growth factor release profile, antimicrobial activity and response towards human Periodontal Ligament fibroblasts (hPDLFs). The results demonstrated that it was possible to obtain stable photocrosslinkable hydrogels incorporating different amounts of PL that can be released in a sustained manner. Furthermore, the incorporation of PL improved (p<0.02) the viscoelastic properties of the hydrogels and enhanced their resilience to the degradation by hyaluronidase (HAase). Additionally, the PL showed to provide antimicrobial properties. Finally, hPDLFs, either seeded or encapsulated into the developed hydrogels, showed enhanced proliferation over time (p<0.05), proportionally to the increasing amounts of PL present in the hydrogel formulations

The fate of steroid estrogens: Partitioning during wastewater treatment and onto river sediments

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media B.V.The partitioning of steroid estrogens in wastewater treatment and receiving waters is likely to influence their discharge to, and persistence in, the environment. This study investigated the partitioning behaviour of steroid estrogens in both laboratory and field studies. Partitioning onto activated sludge from laboratory-scale Husmann units was rapid with equilibrium achieved after 1 h. Sorption isotherms and Kd values decreased in the order 17α-ethinyl estradiol > 17α-estradiol > estrone > estriol without a sorption limit being achieved (1/n >1). Samples from a wastewater treatment works indicated no accumulation of steroid estrogens in solids from primary or secondary biological treatment, however, a range of steroid estrogens were identified in sediment samples from the River Thames. This would indicate that partitioning in the environment may play a role in the long-term fate of estrogens, with an indication that they will be recalcitrant in anaerobic conditions.EPSR

Simultaneous determination of natural and synthetic steroid estrogens and their conjugates in aqueous matrices by liquid chromatography / mass spectrometry

An analytical method for the simultaneous determination of nine free and conjugated steroid estrogens was developed with application to environmental aqueous matrices. Solid phase extraction (SPE) was employed for isolation and concentration, with detection by liquid chromatography/mass spectrometry (LC/MS) using electrospray ionisation (ESI) in the negative mode. Method recoveries for various aqueous matrices (wastewater, lake and drinking water) were determined, recoveries proving to be sample dependent. When spiked at 50 ng/l concentrations in sewage influent, recoveries ranged from 62-89 % with relative standard deviations (RSD) < 8.1 %. In comparison, drinking water spiked at the same concentrations had recoveries between 82-100 % with an RSD < 5%. Ion suppression is a known phenomenon when using ESI; hence its impact on method recovery was elucidated for raw sewage. Both ion suppression from matrix interferences and the extraction procedure has bearing on the overall method recovery. Analysis of municipal raw sewage identified several of the analytes of interest at ng/l concentrations, estriol (E3) being the most abundant. Only one conjugate, estrone 3-sulphate (E1-3S) was observe

An efficient semiparametric maxima estimator of the extremal index

The extremal index $\theta$, a measure of the degree of local dependence in the extremes of a stationary process, plays an important role in extreme value analyses. We estimate $\theta$ semiparametrically, using the relationship between the distribution of block maxima and the marginal distribution of a process to define a semiparametric model. We show that these semiparametric estimators are simpler and substantially more efficient than their parametric counterparts. We seek to improve efficiency further using maxima over sliding blocks. A simulation study shows that the semiparametric estimators are competitive with the leading estimators. An application to sea-surge heights combines inferences about $\theta$ with a standard extreme value analysis of block maxima to estimate marginal quantiles.Comment: 17 pages, 7 figures. Minor edits made to version 1 prior to journal publication. The final publication is available at Springer via http://dx.doi.org/10.1007/s10687-015-0221-

Bone turnover markers for early detection of fracture healing disturbances: A review of the scientific literature

Imaging techniques are the standard method for assessment of fracture healing processes. However, these methods are perhaps not entirely reliable for early detection of complications, the most frequent of these being delayed union and non-union. A prompt diagnosis of such disorders could prevent prolonged patient distress and disability. Efforts should be directed towards the development of new technologies for improving accuracy in diagnosing complications following bone fractures. The variation in the levels of bone turnover markers (BTMs) have been assessed with regard to there ability to predict impaired fracture healing at an early stage, nevertheless the conclusions of some studies are not consensual. In this article the authors have revised the potential of BTMs as early predictors of prognosis in adult patients presenting traumatic bone fractures but who did not suffer from osteopenia or postmenopausal osteoporosis. The available information from the different studies performed in this field was systematized in order to highlight the most promising BTMs for the assessment of fracture healing outcome

It's the product not the polymer: Rethinking plastic pollution

Mismanaged plastic waste poses a complex threat to the environments that it contaminates, generating considerable concern from academia, industry, politicians, and the general public. This concern has driven global action that presents a unique opportunity for widespread environmental engagement beyond the immediate problem of the persistence of plastic in the environment. But for such an opportunity to be realized, it is vital that the realities of plastic waste are not misrepresented or exaggerated. Hotspots of plastic pollution, which are often international in their source, present complex environmental problems in certain parts of the world. Here we argue, however, that the current discourse on plastic waste overshadows greater threats to the environment and society at a global scale. Antiplastic sentiments have been exploited by politicians and industry, where reducing consumers' plastic footprints are often confused by the seldom‐challenged veil of environmental consumerism, or “greenwashing.” Plastic is integral to much of modern day life, and regularly represents the greener facilitator of society's consumption. We conclude that it is the product, not the polymer that is driving the issue of plastic waste. Contemporary consumption and disposal practices are the root of much of the anthropogenic waste in the environment, plastic, or not. Effective environmental action to minimize plastic in the environment should be motivated by changes in consumption practices, policies, and product design, and should be informed by objective science and legislation

Enzymatic degradation of starch thermoplastic blends using samples of different thickness

The material studied was a thermoplastic blend of corn starch with a poly(ethylene-vinyl alcohol) copolymer, SEVA-C. The influence of both the material’s exposed surface and enzyme concentration on degradation kinetics was studied. As α-amylase is present in the blood plasma, experiments were performed, varying the material thickness and the α-amylase between 50 and 100 units/l, at 37°C, lasting up to 90 days. Four different batches using SEVA-C and starch samples of different thickness were performed. The positive correlation between degradation rate and the exposed material surface was confirmed, since thin films with larger exposed surfaces were degraded faster than thick square plates having the same total mass. The degradation extent depends on the total amount of amorphous starch present in the formulation rather than on the amount of enzyme used and the minimum thickness to ensure maximum degradation was estimated to be close to 0.25 mm