Microbially influenced corrosion and rust tubercle formation on sheet piles in freshwater systems.

The extent of how complex natural microbial communities contribute to metal corrosion is still not fully resolved, especially not for freshwater environments. In order to elucidate the key processes, we investigated rust tubercles forming massively on sheet piles along the river Havel (Germany) applying a complementary set of techniques. In-situ microsensor profiling revealed steep gradients of O2 , redox potential and pH within the tubercle. Micro-computed tomography and scanning electron microscopy showed a multi-layered inner structure with chambers and channels and various organisms embedded in the mineral matrix. Using Mössbauer spectroscopy we identified typical corrosion products including electrically conductive iron (Fe) minerals. Determination of bacterial gene copy numbers and sequencing of 16S rRNA and 18S rRNA amplicons supported a densely populated tubercle matrix with a phylogenetically and metabolically diverse microbial community. Based on our results and previous models of physic(electro)chemical reactions, we propose here a comprehensive concept of tubercle formation highlighting the crucial reactions and microorganisms involved (such as phototrophs, fermenting bacteria, dissimilatory sulphate and Fe(III) reducers) in metal corrosion in freshwaters.

Phytoplankton gross primary production increases along cascading impoundments in a temperate, low-discharge river: Insights from high frequency water quality monitoring.

Damming alters carbon processing along river continua. Estimating carbon transport along rivers intersected by multiple dams requires an understanding of the effects of cascading impoundments on the riverine metabolism. We analyzed patterns of riverine metabolism and phytoplankton biomass (chlorophyll a; Chla) along a 74.4-km river reach intersected by six low-head navigation dams. Calculating gross primary production (GPP) from continuous measurements of dissolved oxygen concentration, we found a maximum increase in the mean GPP by a factor of 3.5 (absolute difference of 0.45 g C m-3 d-1) along the first 26.5 km of the study reach, while Chla increased over the entire reach by a factor of 2.9 (8.7 µg l-1). In the intermittently stratified section of the deepest impoundment the mean GPP between the 1 and 4 m water layer differed by a factor of 1.4 (0.31 g C m-3 d-1). Due to the strong increase in GPP, the river featured a wide range of conditions characteristic of low- to medium-production rivers. We suggest that cascading impoundments have the potential to stimulate riverine GPP, and conclude that phytoplankton CO2 uptake is an important carbon flux in the river Saar, where a considerable amount of organic matter is of autochthonous origin.

A Simple Compartment Model for the Dynamical Behavior of Medically Derived 131I in a Municipal Wastewater Treatment Plant.

A compartmental model for the reactive flow of the radioisotope 131I, frequently introduced into the sewer system at varying concentrations through radiotherapy of thyroid diseases, has been developed for an existing municipal wastewater treatment plant (WWTP). It includes the transition of activity from dissolved to suspended particulate and colloid matter, and the separation of phases in sedimentation basins. It has been parametrized by experimental data obtained at key locations in the plant, and validated by measured time series of activity concentration of inflow and outflow. It can be used to predict concentrations at various locations in the WWTP, including outflow and primary sludge. It can also be reparameterized to be applied to other WWTPs based on activated sludge systems. In principle, a modification for the simulation of other nuclides is possible as well. As radioisotopes of iodine form an important part of accidental releases from nuclear power plants, they are monitored, and their environmental behavior is predicted by models. The present work can contribute to these efforts by improving predictions of radioiodine transport in the public sewer system.

Pacific Proving Grounds radioisotope imprint in the Philippine Sea sediments.

Radionuclide concentrations were studied in sediment cores taken at the continental slope of the Philippine Sea off Mindanao Island in the equatorial Western Pacific. High resolution deposition records of anthropogenic radionuclides were collected at this site. Excess 210Pb together with excess 228Th and anthropogenic radionuclides provided information about accumulation rates. Concentrations of Am and Pu isotopes were detected by gamma spectrometry, alpha spectrometry and ICP-MS. The Pu ratios indicate a high portion (minimum of 60%) of Pu from the Pacific Proving Grounds (PPG). This implies that the transport of PPG derived plutonium with the Mindanao Current southward is similarly effective as the previously known transport towards the north with the Kuroshio Current. The record is compared to other studies from northwest Pacific marginal seas and Lombok basin in the Indonesian Archipelago. The sediment core top was found to contain a 6 cm thick layer dominated by terrestrial organic matter, which was interpreted as a result of the 2012 Typhoon Pablo-related fast deposition.

The physicochemical distribution of 131I in a municipal wastewater treatment plant.

As a consequence of therapeutic and diagnostic treatment of patients with thyroid diseases, 131I is introduced into the sewage system on a regular basis. This presents an opportunity to use the 131I as a tracer to study its partitioning and transport within a wastewater treatment plant (WWTP). In the case of nuclear accidents where 131I is one of the most prominent nuclides, an understanding of iodine partitioning and transport will be valuable for developing models that may prognosticate the activity concentrations in sludge and outflow, especially after an accidental input. In this study, samples from various locations inside a municipal WWTP were taken and for each sample, three different fractions were separated by a chemical extraction process. These fractions were analysed for their 131I activity concentrations by gamma-ray spectroscopy. While about 30% of the radioiodine activity in the inflow is associated with organic molecules, this amounts to about 90% after biological treatment. This is caused by the accumulation of 131I bound to organic matter in the return sludge and by a transfer of 131I from the inorganic to the organic fractions, most likely mediated by microbial action. In the outflow, inorganic and low-molecular 131I is dominant, but the overall activity concentration is reduced to about 50-75%.

Continuous transport of Pacific-derived anthropogenic radionuclides towards the Indian Ocean.

Unusually high concentrations of americium and plutonium have been observed in a sediment core collected from the eastern Lombok Basin between Sumba and Sumbawa Islands in the Indonesian Archipelago. Gamma spectrometry and accelerator mass spectrometry data together with radiometric dating of the core provide a high-resolution record of ongoing deposition of anthropogenic radionuclides. A plutonium signature characteristic of the Pacific Proving Grounds (PPG) dominates in the first two decades after the start of the high yield atmospheric tests in 1950's. Approximately 40-70% of plutonium at this site in the post 1970 period originates from the PPG. This sediment record of transuranic isotopes deposition over the last 55 years provides evidence for the continuous long-distance transport of particle-reactive radionuclides from the Pacific Ocean towards the Indian Ocean.

Nasal Reconstruction: Extending the Limits.

Reconstructing the 3-dimensional structure of the nose requires the maintenance of its aesthetic form and function. Restoration of the correct dimension, projection, skin quality, symmetrical contour, and function remains problematic. Consequently, modern approaches of nasal reconstruction aim at rebuilding the units rather than just covering the defect. However, revising or redoing a failed or insufficient reconstruction remains very challenging and requires experience and creativity. Here, we present a very particular case with a male patient, who underwent 37 operations elsewhere and presented with a failed nasal reconstruction. We describe and illustrate the complex steps of the nasal rereconstruction, including the reconstruction of the forehead donor site, surgical delay procedures for lining, and the coverage with a third paramedian forehead flap.

Recent advances in metathesis-derived polymers containing transition metals in the side chain.

This account critically surveys the field of side-chain transition metal-containing polymers as prepared by controlled living ring-opening metathesis polymerization (ROMP) of the respective metal-incorporating monomers. Ferrocene- and other metallocene-modified polymers, macromolecules including metal-carbonyl complexes, polymers tethering early or late transition metal complexes, etc. are herein discussed. Recent advances in the design and syntheses reported mainly during the last three years are highlighted, with special emphasis on new trends for superior applications of these hybrid materials.

A Cohort Study of Paramedian Forehead Flap in 2 Stages (87 Flaps) and 3 Stages (100 Flaps).

BACKGROUND: In nasal reconstruction, the paramedian forehead flap is traditionally performed in 2 stages. To minimize the risk of flap necrosis, Millard described a 3-stage technique in a series of 5 cases in 1974. In this technique, an intermediate step of flap thinning is performed after flap transfer and before pedicle division. In this article, we compare the 2- and 3-stage techniques of paramedian forehead flaps for nasal reconstruction to determine the type and prevalence of complications related to each procedure. METHODS: Here, we present a retrospective review of a prospectively maintained database of paramedian forehead flaps for nasal reconstruction performed during a period of 6 years. We included all patients with 2- (n=87) and 3-stage (n=100) paramedian forehead flaps who had consistent and complete electronic patient records and followed them up for at least 6 months after pedicle division. We performed a regression analysis to adjust for the unequal distribution of complex cases. RESULTS: Demographic factors and the causes for the nasal defects were similar in both groups. Although the nasal reconstructions were significantly more complex in the 3-stage group, the rate of partial forehead flap necrosis was similar in both groups (2-stage, 3.4%; 3-stage, 5%; P=0.601). A regression analysis showed that the relative risk of partial flap necrosis in complex cases did not differ significantly between groups (relative risk, 0.80; P=0.705). CONCLUSIONS: To our knowledge, our study is the largest series published to date and the first one to compare the prevalence of forehead flap necrosis in the 2- versus the 3-stage technique for paramedian forehead flaps. We found no evidence that the use of a 3-stage forehead flap lowers the prevalence of necrosis. Until larger multicenter studies or meta-analyses can be conducted, smaller yet well-conducted studies such as the present one provide critical data and represent an important contribution to the field. Future research should investigate whether the 3-stage technique produces better aesthetic results than the 2-stage technique.

Detection of long-lived europium-152 in samarium-153-lexidronam.

Samarium-153-lexidronam is a radiopharmaceutical used for pain palliation therapy in patients suffering from multilocular bone metastases. The postinjection residual of four pharmaceutical vials of (153)Sm-lexidronam and one patient were investigated for contamination with other isotopes using high-resolution gamma spectroscopy. In the spectra besides the already known contaminants europium-154, (155)Eu and (156)Eu, europium-152 was discovered in vitro and also in vivo. (152)Eu disintegrates with a half-life of 13.5years emitting a multitude of high energy photons. Due to these properties, it does not only affect radioactive waste management regarding e.g. the disposal of the postinjection residual, but also poses an additional dose burden to the patient and to third persons. In the postinjection residual a mean activity concentration of 10.4±1.1kBq europium-152 per GBq (153)Sm was detected. 62days after isotope application, 15.8±4.0kBq of (152)Eu were found within the patient. The lifetime effective dose to the patient from the europium impurities was determined using a multicompartment model. For (152)Eu the effective dose was 2.1mSv/GBq (153)Sm-lexidronam and the total effective dose from all impurities was 6.1mSv/GBq (153)Sm-lexidronam. The total absorbed dose to third persons caused by the europium impurities was estimated as 0.6mGy/GBq (153)Sm-lexidronam.

Skin-fat-graft: a simple tool for reconstruction of small deep defects of the nose.

Small deep defects of the nose after resection of benign or malignant skin tumors are a common challenge in facial plastic surgery daily routine. The use of local flaps has several disadvantages for what reason they are a minor or no option especially in certain localizations in the lower third of the nose. Many elder patients suffer from comorbidities where complex more-staged reconstructional procedures drop out. We present a technique of nasal defect closure with a skin-fat composite graft. Between April 2010 and July 2013, we treated 42 patients with a total of 46 skin-fat-grafts to the nose. We reevaluated the esthetic and functional outcome in a retrospective analysis. In 80% of the cases, the results were rated excellent to satisfactory, 20% fair to poor. Reasons for worse validation were color and contour differences of grafts and surrounding tissue as well as alar retraction in very few cases. Nevertheless, we consider skin-fat-grafts to be a useful tool in single-layer nasal reconstruction in defects of smaller size.

One-stage nasal soft tissue reconstruction with local flaps.

Because of better public education and earlier diagnosis of skin tumors, the number of soft tissue defects of the nose with limited size and depth after tumor resection is increasing. A variety of surgical methods such as skin grafts, regional flaps such as forehead flap, and local flaps have been described. The method of choice is dependent on the defect size, localization, skin structure and the wishes and expectations, and general condition of the patient. Nasal reconstruction for soft tissue defects in the supratip area, dorsum, and sidewalls using local rotation and/or advancement flaps is our primary option. But achieving supreme results with these non-subunit-based techniques is still a challenge. Showing schematic figures and case studies, this article is aimed at assisting surgeons in the planning and decision making of which flap is appropriate for the reconstruction of soft tissue defects of the nose.

Lining in nasal reconstruction.

Restoring nasal lining is one of the essential parts during reconstruction of full-thickness defects of the nose. Without a sufficient nasal lining the whole reconstruction will fail. Nasal lining has to sufficiently cover the shaping subsurface framework. But in addition, lining must not compromise or even block nasal ventilation. This article demonstrates different possibilities of lining reconstruction. The use of composite grafts for small rim defects is described. The limits and technical components for application of skin grafts are discussed. Then the advantages and limitations of endonasal, perinasal, and hingeover flaps are demonstrated. Strategies to restore lining with one or two forehead flaps are presented. Finally, the possibilities and technical aspects to reconstruct nasal lining with a forearm flap are demonstrated. Technical details are explained by intraoperative pictures. Clinical cases are shown to illustrate the different approaches and should help to understand the process of decision making. It is concluded that although the lining cannot be seen after reconstruction of the cover it remains one of the key components for nasal reconstruction. When dealing with full-thickness nasal defects, there is no way to avoid learning how to restore nasal lining.

Framework fabrication with rib cartilage in partial and total nasal reconstruction.

The framework reconstruction of the nose is a significant and complex component of its partial or total reconstruction. On the one hand, the design of the individual framework parts is based on the anatomic nature of available rib or ear cartilage, which must on the other hand be adapted to the anatomic characteristics of the defect. The framework parts must be anchored not only to each other but also stably to the facial skeleton. The symmetry of the framework reconstruction is an essential component of the aesthetics of the reconstructed nose. If these points are already considered in planning, the reconstruction of the nasal framework can be standardized insofar as the same principles for the basic design of the individual parts as well as stable solutions for the anchoring points can be chosen. With reproducible techniques, functionally and aesthetically good to very good results can be achieved, including in the long term. The surgeon must possess special skills in the field of nasal reconstruction to correctly choose, apply, and combine the various techniques of nasal framework reconstruction.

Nasal reconstruction with the paramedian forehead flap--details for success.

This article is focused on technical details for successfully reconstructing the nasal skin cover in parts or totally. Nasal reconstruction is based on the successful reconstruction of the inner lining and the nasal framework in three-layer defects. The details to be considered include planning the flap, subunit reconstruction and outline of margins, dealing with hair-bearing forehead skin, sequence of stages, intermediate debulking, details of pedicle dissection, brow reconstruction, forehead closure, forehead expansion, and complication management.

Nasal reconstruction in children.

The nose represents the center of the face. The nasal shape changes with the progression from infancy to adulthood. In newborns, the main supporting structure of the nose is the dorsal septal cartilage; it is the facial growth center. The loss of septal cartilage at different ages leads to various facial syndromes involving the nose, maxilla, and orbita. Therefore, every surgical treatment can compromise not only the nasal growth but also the growth of the whole face. Childhood trauma or a malformation of the nose can also cause enormous functional impairments similar to those caused by surgical treatments. Our contribution represents different aspects of nasal deformities and their treatment. An individual concept is indispensable to reach the best compromise in all cases. The postulate of an early treatment gives priority to physical and mental damage control. The late therapy concept uses the inimitable potential of the growth of different tissues needed for a septoplasty and should be protected from iatrogenic impairment. We recommend a first-line pediatric nasal reconstruction, an attentive follow-up, and finally, a secondary nasal reconstruction in the adult patient if required for achieving normalcy.

Nasal reconstruction in heminasal deficiency (proboscis lateralis): two case reports, with airway reconstruction in one case.

Proboscis lateralis is a very rare congenital malformation with heminasal hypoplasia or aplasia. The affected side is represented by a trunk (proboscis) which can be positioned from the upper eyelid down to the alar base. We present two cases of proboscis lateralis, one in which we reconstructed an airway. The first case is a 16-year-old male patient who presented with heminasal aplasia. Immediately after birth, a proboscis lateralis was resected from the right upper eyelid as primary treatment elsewhere. We reconstructed the nose using costal cartilage as framework. A paramedian forehead flap was transposed to give the patient a nose with adult dimensions. We made no attempt to reconstruct an airway in this case as unilateral nasal breathing appeared adequate. The second case is a 14-year-old male patient who presented with heminasal aplasia on his right side, where a nodule-like appendix was existent with a fistula underneath. A computed tomographic scan revealed an existing hypoplastic posterior nasal airway and a complete ventilated sinus system. The fact that there was an existing posterior airway encouraged us to construct an anterior airway to create an airflow passage. Costal cartilage was taken for framework reconstruction and nasal skin was completely replaced by a paramedian forehead flap. The reconstructed airflow passage was stable.

Estimating the distribution of radionuclides in agricultural soils - dependence on soil parameters.

In this study it is shown how radionuclide distributions in agricultural soils and their dependence on soil parameters can be quantitatively estimated. The most important sorption and speciation processes have been implemented into a numerical model using the geochemical code PHREEQC that is able to include specific soil and soil solution compositions. Using this model, distribution coefficients (Kd values) for the elements Cs, Ni, U and Se have been calculated for two different soil types. Furthermore, the dependencies of these Kd values on various soil parameters (e.g. pH value or organic matter content) have been evaluated. It is shown that for each element, an individual set of soil parameters is relevant for its solid-liquid distribution. The model may be used for the calculation of input parameters used by reference biosphere models (e.g. used for the risk assessment of nuclear waste repositories).

Sediment trapping by dams creates methane emission hot spots.

Inland waters transport and transform substantial amounts of carbon and account for ∼18% of global methane emissions. Large reservoirs with higher areal methane release rates than natural waters contribute significantly to freshwater emissions. However, there are millions of small dams worldwide that receive and trap high loads of organic carbon and can therefore potentially emit significant amounts of methane to the atmosphere. We evaluated the effect of damming on methane emissions in a central European impounded river. Direct comparison of riverine and reservoir reaches, where sedimentation in the latter is increased due to trapping by dams, revealed that the reservoir reaches are the major source of methane emissions (∼0.23 mmol CH4 m(-2) d(-1) vs ∼19.7 mmol CH4 m(-2) d(-1), respectively) and that areal emission rates far exceed previous estimates for temperate reservoirs or rivers. We show that sediment accumulation correlates with methane production and subsequent ebullitive release rates and may therefore be an excellent proxy for estimating methane emissions from small reservoirs. Our results suggest that sedimentation-driven methane emissions from dammed river hot spot sites can potentially increase global freshwater emissions by up to 7%.