bluuebunny/crossref_metadata_2025 huggingface dataset:
Process Technology for Waste Wood Processing
Authors: Eisenlauer Moritz , Graf Hannah , Teipel Ulrich
Published: February 2018

In den letzten Jahren hat die Nutzung nachwachsender Rohstoffe stark zugenommen. Um die Nachfrage decken zu können, müssen neue Rohstoffströme erschlossen, aber auch die Prozessschritte bei der Nutzung dieser in ihrer Effizienz gesteigert werden. Altholz bzw. Recyclingholz stellt einen bis heute wenig genutzten Rohstoffstrom dar. Ein wesentlicher Aspekt bei der Nutzung dieser Rohstoffe ist die Zerkleinerung. In dieser Arbeit wurde Recyclingholz in einer Hammer‐ und einer Schneidmühle zerkleinert. Dabei wurde der Einfluss von Prozessparametern und des Rohstofftyps auf die Zerkleinerungsenergie und die Zerkleinerungsprodukte untersucht.
Formation and Vaporization of Hydrocarbons During Cobalt‐Catalysed Fischer‐Tropsch Synthesis
Authors: Rößler Stefan , Kern Christoph , Jess Andreas
Published: February 2018

During the initial phase of low‐temperature Fischer‐Tropsch synthesis, the pore system of the catalyst is filled with liquid hydrocarbons. The investigations in a magnetic suspension balance with a cobalt catalyst revealed that the filling period may take several days or even more and strongly depends on the conditions such as temperature and H2‐to‐CO ratio. A numerical model of the pore filling process was developed to gain a better understanding of the parameters that determine this process and of their impact on the filling time. The model is in good agreement with the experimental data.
Adverse pregnancy outcomes and future maternal cardiovascular disease
Authors: Hauspurg Alisse , Ying Wendy , Hubel Carl A. , Michos Erin D. , Ouyang Pamela
Published: February 2018

Cardiovascular disease (CVD) remains the leading cause of death in women. Although traditional risk factors increase later‐life CVD, pregnancy‐associated complications additionally influence future CVD risk in women. Recent guidelines for the prevention of CVD in women have added adverse pregnancy outcomes as major CVD risk factors. Studies have shown that women with a history of preeclampsia, gestational diabetes, preterm delivery, and delivery of a small‐for‐gestational‐age infant have an increased risk of developing cardiometabolic risk factors and subsequent CVD. A history of multiple adverse pregnancy outcomes further increases this risk. It has been suggested that these pregnancy complications may unmask preexisting elevated CVD risk; however, whether the pathophysiologic changes underlying these conditions directly result in long‐term cardiovascular damage is unclear. The purpose of this review was to highlight the associations between adverse pregnancy outcomes and future CVD, and to emphasize the importance of considering pregnancy history in assessing a woman's CVD risk. Targeted efforts to initiate screening and risk‐reduction strategies in women with prior history of pregnancy complications, particularly lifestyle modification, may help decrease the burden of CVD in women.
Rates of Ligand Exchange around the Bis‐Oxalato Complex [NpO2(C2O4)2]3− Measured by Using Multinuclear NMR Spectroscopy under Neutral to Semi‐Alkaline Conditions
Authors: Pilgrim Corey D. , Mason Harris E. , Zavarin Mavrik , Casey William H.
Published: February 2018

The kinetics of ligand exchange between the free oxalate ion, C2O42−, and the bis‐oxalato NpV complex, [NpO2(C2O4)2]3−, in aqueous solution are reported by using 13C and 17O NMR spectroscopy methods. Rates of exchange were measured in the pH regime of 6.5–9.0, at which speciation is shown to be suitably simple. Because the neptunium(V) complex is paramagnetic, the rates of ligand exchange were estimated by following the width of the 13C and 17O signals assigned to the free oxalate ion in solution and by applying the Swift–Connick method for measuring rates of exchange. A set of experiments were conducted in which pH and total oxalate concentration were varied, and the linear dependence of the rate on these parameters was demonstrated. Variable‐temperature NMR spectroscopy was also performed to measure activation parameters of complexation. At pH<8.0, ΔH≠=16.9 ±4.9 kJ mol−1 and ΔS≠=−116.3 ±17.1 kJ mol−1 K−1, whereas at pH>8.0 there is almost no dependence on temperature, which is interpreted to indicate that hydrolysis is coupled to ligand exchange under these conditions.
Photo‐ and Electrochemical Properties of a CO2 Reducing Ruthenium–Rhenium Quaterpyridine‐Based Catalyst
Authors: Frayne Liam , Das Nivedita , Paul Avishek , Amirjalayer Saeed , Buma Wybren J. , Woutersen Sander , Long Conor , Vos Johannes G. , Pryce Mary T.
Published: February 2018

The bridging ligand 2,2′,5′,3′′,6′′,2′′′‐quaterpyridine was utilised to tether [(bpy)2Ru]2+ and [Re(CO)3Cl] subunits for the purpose of photocatalytic CO2 reduction. The photophysics and electrochemistry of the complex and associated mononuclear species are reported herein, in addition to photocatalytic, picosecond time‐resolved infrared and computational studies. Photophysical, time‐resolved IR, and electrochemical data together with quantum chemical calculations indicate weak communication between the two metal centres. As a result of the electron‐withdrawing effect of the ligand on both the Ru and Re subunits, the reducing power of the photosensitiser and catalytic unit were significantly attenuated relative to the intermolecular approach utilising [(bpy)3Ru]2+ and (bpy)Re(CO)3Cl.
Cleaning effect of osteoconductive powder abrasive treatment on explanted human implants and biofilm‐coated titanium discs
Authors: Tastepe Ceylin S. , Lin Xingnan , Werner Arie , Donnet Marcel , Wismeijer Daniel , Liu Yuelian
Published: February 2018

The aim of this study is to test the cleaning effect and surface modification of a new implant surface treatment on explanted dental implants and titanium discs. It is a modified air powder abrasive (APA) treatment applied using osteoconductive powders. Twenty‐eight in vitro Ca‐precipitated organic film‐coated titanium discs and 13 explanted dental implants were treated. In a 2‐step approach, 3 powders were used: hydroxylapatite (HA) and biomimetic calcium phosphate (BioCaP), which are osteoconductive, and erythritol, which is not. APA treatment was applied. (Air pressure: 2.4 bar; water flow for cleaning: 41.5 ml/min, for Coating 1: 2.1 ml/min, and for Coating 2: 15.2 ml/min.) The test groups were as follows: Group 1: HA cleaning + BioCaP Coating 1; Group 2: HA cleaning + BioCaP Coating 2; Group 3: erythritol cleaning + BioCaP Coating 1; Group 4: erythritol cleaning + BioCaP Coating 2; Group 5: HA cleaning; Group 6: erythritol cleaning; and control: no powder. Cleaned areas were calculated by point counting method. Surface changes and chemical content were evaluated using light microscopy, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy. Cleaning effect between groups was compared by a pairwise Student's t test. The significance level was fixed at p < .05. Cleaning effect on the discs was 100% in all test groups and 5% in the control. Powder particles in varying size and shape were embedded on the surface. All HA‐ or CaP‐treated surfaces showed Ca and P content but no surface damage. Calcified biofilm remnants were removed from the implant surface by the test groups, whereas in control groups, they remained. APA treatment with CaP and HA powders under clinically applicable pressure settings gives positive results in vitro; therefore, they could be promising when used in vivo.
Promoting Ethylene Selectivity from CO2 Electroreduction on CuO Supported onto CO2 Capture Materials
Authors: Yang Hui‐Juan , Yang Hong , Hong Yu‐Hao , Zhang Peng‐Yang , Wang Tao , Chen Li‐Na , Zhang Feng‐Yang , Wu Qi‐Hui , Tian Na , Zhou Zhi‐You , Sun Shi‐Gang
Published: February 2018

Cu is a unique catalyst for CO2 electroreduction, since it can catalyze CO2 reduction to a series of hydrocarbons, alcohols, and carboxylic acids. Nevertheless, such Cu catalysts suffer from poor selectivity. High pressure of CO2 is considered to facilitate the activity and selectivity of CO2 reduction. Herein, a new strategy is presented for CO2 reduction with improved C2H4 selectivity on a Cu catalyst by using CO2 capture materials as the support at ambient pressure. N‐doped carbon (NxC) was synthesized through high‐temperature carbonization of melamine and l‐lysine. We observed that the CO2 uptake capacity of NxC depends on both the microporous area and the content of pyridinic N species, which can be controlled by the carbonization temperature (600–800 °C). The as‐prepared CuO/NxC catalysts exhibit a considerably higher C2H4 faradaic efficiency (36 %) than CuO supported on XC‐72 carbon black (19 %), or unsupported CuO (20 %). Moreover, there is a good linear relationship between the C2H4 faradaic efficiency and CO2 uptake capacity of the supports for CuO. The local high CO2 concentration near Cu catalysts, created by CO2 capture materials, was proposed to increase the coverage of CO intermediate, which is favorable for the coupling of two CO units in the formation of C2H4. This study demonstrates that pairing Cu catalysts with CO2 capture supports is a promising approach for designing highly effective CO2 reduction electrocatalysts.
Conservation value of low‐productivity forests measured as the amount and diversity of dead wood and saproxylic beetles
Authors: Hämäläinen Aino , Strengbom Joachim , Ranius Thomas
Published: February 2018

In many managed landscapes, low‐productivity land comprises most of the remaining relatively untouched areas, and is often over‐represented within protected areas. The relationship between the productivity and conservational value of a site is poorly known; however, it has been hypothesized that biodiversity increases with productivity due to higher resource abundance or heterogeneity, and that the species communities of low‐productivity land are a nested subset of communities from more productive land. We tested these hypotheses for dead‐wood‐dependent beetles by comparing their species richness and composition, as well as the amount and diversity of dead wood, between low‐productivity (potential forest growth <1 m3·ha−1·yr−1) and high‐productivity Scots pine‐dominated stands in Sweden. We included four stand types: stands situated on (1) thin soils and (2) mires (both low‐productivity), (3) managed stands, and (4) unmanaged stands set aside for conservation purposes (both high‐productivity). Beetle species richness and number of red‐listed species were highest in the high‐productivity set‐asides. Species richness was positively correlated with the volume and diversity of dead wood, but volume appeared to be a better predictor than diversity for the higher species richness in set‐asides. Beetle species composition was similar among stand types, and the assemblages in low‐productivity stands were largely subsets of those in high‐productivity set‐asides. However, 11% of all species and 40% of red‐listed species only occurred in high‐productivity stands, while no species were unique to low‐productivity stands. We conclude that low‐productivity forests are less valuable for conservation than high‐productivity forest land. Given the generally similar species composition among stand types, a comparable conservational effect could be obtained by setting aside a larger area of low‐productivity forest in comparison to the high‐productivity. In terms of dead wood volumes, 1.8–3.6 ha of low‐productivity forest has the same value as 1 ha of unmanaged high‐productivity forest. This figure can be used to estimate the conservation value of low‐productivity forests; however, as high‐productivity forests harbored some unique species, they are not completely exchangeable.
Hydrological and environmental variables outperform spatial factors in structuring species, trait composition, and beta diversity of pelagic algae
Authors: Wu Naicheng , Qu Yueming , Guse Björn , Makarevičiūtė Kristė , To Szewing , Riis Tenna , Fohrer Nicola
Published: February 2018

There has been increasing interest in algae‐based bioassessment, particularly, trait‐based approaches are increasingly suggested. However, the main drivers, especially the contribution of hydrological variables, of species composition, trait composition, and beta diversity of algae communities are less studied. To link species and trait composition to multiple factors (i.e., hydrological variables, local environmental variables, and spatial factors) that potentially control species occurrence/abundance and to determine their relative roles in shaping species composition, trait composition, and beta diversities of pelagic algae communities, samples were collected from a German lowland catchment, where a well‐proven ecohydrological modeling enabled to predict long‐term discharges at each sampling site. Both trait and species composition showed significant correlations with hydrological, environmental, and spatial variables, and variation partitioning revealed that the hydrological and local environmental variables outperformed spatial variables. A higher variation of trait composition (57.0%) than species composition (37.5%) could be explained by abiotic factors. Mantel tests showed that both species and trait‐based beta diversities were mostly related to hydrological and environmental heterogeneity with hydrological contributing more than environmental variables, while purely spatial impact was less important. Our findings revealed the relative importance of hydrological variables in shaping pelagic algae community and their spatial patterns of beta diversities, emphasizing the need to include hydrological variables in long‐term biomonitoring campaigns and biodiversity conservation or restoration. A key implication for biodiversity conservation was that maintaining the instream flow regime and keeping various habitats among rivers are of vital importance. However, further investigations at multispatial and temporal scales are greatly needed.
A Fluidic Vibrational Energy Harvester for Implantable Medical Device Applications
Authors: INOUE SATOSHI , TAKAHASHI TAKUYA , KUMEMURA MOMOKO , ISHIBASHI KAZUNORI , FUJITA HIROYUKI , HASHIGUCHI GEN , TOSHIYOSHI HIROSHI
Published: February 2018

In this paper, we report on a proof‐of‐concept level energy harvester device that could earn electric power of 0.093 μW/cm2 by the fluidic motion in a polydimethylsiloxane microfluidic channel placed on a silicon substrate with built‐in permanent electrical charges or so‐called electrets. Targeting implantable medical devices such as respiratory pacemaker, the heart beat or aspiration is thought to be the source of motion as a final shape of the energy harvesting system.
Multiscale Structured Particle‐Based Zinc Anodes in Non‐Stirred Alkaline Systems for Zinc–Air Batteries
Authors: Titscher Paul , Riede Jens‐Christian , Wiedemann Janosch , Kunz Ulrich , Kwade Arno
Published: February 2018

Primary zinc–air batteries are well established in the commercial market, but secondary zinc–air batteries still suffer from challenging problems. Multiple charge and discharge cycles result in zinc density migration and the formation of passivating by‐products, which can ultimately change the shape of the zinc anode. This work focuses on the use of zinc particles in combination with highly structured current collectors in a cell with a stagnant alkaline electrolyte. Copper weave and copper foam were used as current collectors. The influences of the zinc particle size, the mass loading and the macroscopic structure of the anodes were characterized. Highly structured electrode designs led to improved discharge and cycling performances. Due to the increased active surface area, the electrodes take advantage of highly distributed zinc deposits. The results reveal that the use of multiscale structures within the zinc anode can be beneficial for further applications.
Less of a bird's song than a hard rock ensemble
Authors: Hosfield Robert , Cole James , McNabb John
Published: February 2018

Corbey et al. (2016) propose that the Acheulean handaxe was, at least in part, under genetic control. An alternative perspective is offered here, focusing on the nature of the Acheulean handaxe and the archaeological record, and re‐emphasizing their status as cultural artefacts. This is based on four main arguments challenging the proposals of Corbey et al. Firstly, handaxes do not have to track environmental variation to be a cultural artefact, given their role as a hand‐held butchery knife or multi‐purpose tool. Secondly, while handaxe shapes do cluster around a basic bauplan, there is also significant variability in the Acheulean handaxe record, characterized by site‐specific modal forms and locally expressed, short‐lived, idiosyncratic traits. Critically, this variability occurs in both time and space, is multi‐scalar, and does not appear to be under genetic control. Thirdly, handaxes were produced in social contexts, within which their makers grew up exposed to the sights and sounds of artefact manufacture. Finally, the localized absences of handaxes at different times and places in the Lower Paleolithic world is suggestive of active behavioral choices and population dynamics rather than genetic controls.
Building Information Modelling in mechanised shield tunnelling – A practitioner's outlook to the near future
Authors: Stascheit Janosch , Ninić Jelena , Meschke Günther , Hegemann Felix , Maidl Ulrich
Published: February 2018

The contribution takes a glance at the application of BIM technologies in the design and construction phases of shield tunnelling projects. The intention is to show how Building Information Modelling can be translated into actual benefit, not only in the operation phase but also in the design and construction phases of bored tunnels. Emphasising the integrative character of referencing data uniformly in space and time, examples are given of seamless communication between 3D geometrical modelling, efficient numerical simulation and model adaptation based on measured data acquired during the boring process. The article covers the complete range from predesign through structural analysis and detailed design until the actual excavation process including its interactions with the environment. Special emphasis is given to data management, which is the key to transforming a mere 3D visualisation into a Building Information Model. The article therefore presents a concept for database‐supported, web‐based integration of software modules for geometrical modelling in various levels of detail, efficient numerical simulation tools that are based upon this representation, and process controlling that manages all data acquired during the construction process in a spatially and temporally coordinated reference system.
Metro Doha Green Line – More than 30 km of tunnel in 18 months
Authors: Rengshausen Rainer , Weiner Thorsten
Published: February 2018

The capital of Qatar, Doha is being increasingly turned into a modern centre for industry, trade and sport. One essential precondition for this is the development of high‐capacity infrastructure with modern means of transport. This includes the construction of an underground railway network, which has to be completed in a very short time due to the football World Cup taking place in Qatar in 2022. The (part) project ”Metro Green Line Underground“ was awarded in summer 2013 to a Joint Venture comprised of Porr (lead), the Saudi Binladin Group and the local construction company HBK. It includes the turnkey completion of the underground part of the Green Line in the future underground system. This includes two tunnels with a length of 17 km each, six stations, crossover structures, several emergency exits and 32 cross passages and two road underpasses. The shield drive for the running tunnels began in late summer 2014 and could be completed after only 18 months of construction time in early 2016. In addition to explaining how the simultaneous operation of six EPB machines was successfully mastered, this article also describes the conventional tunnelling of the various connection and underpass structures under inner‐city conditions.
An evaluation of delay to reinforcement and mand variability during functional communication training
Authors: Muething Colin S. , Falcomata Terry S. , Ferguson Raechal , Swinnea Samantha , Shpall Cayenne
Published: February 2018

Children with autism spectrum disorder and other developmental disabilities often exhibit invariant responding (i.e., restricted behavioral repertoires), deficits in communication, and challenging behavior. Approaches demonstrated in the basic and applied literature to increase response variability include extinction, lag schedules of reinforcement, and percentile schedules of reinforcement. Results of basic studies have also indicated that delays to reinforcement often produce increases in response variability. The purpose of the current study was to evaluate the effects of a delay to reinforcement on the variability of communication responses during functional communication training with individuals with developmental disabilities and histories of engaging in challenging behavior. Results indicated that delays to reinforcement increased mand variability with all four participants with variable effects on challenging behavior across participants.
A simple mathematical model capable of describing the microbial production of poly(hydroxyalkanoates) under carbon‐ and nitrogen‐limiting growth conditions
Authors: Vega Roberto , Castillo Augusto
Published: February 2018

BACKGROUND

Poly(hydroxyalkanoates) (PHAs) are biodegradable polymers that can replace conventional plastics, but microbial production of PHAs must be optimized for commercial success. The aim of this study is to provide a simple mathematical model based on previous studies in the literature to represent the production of PHAs in chemostat and batch cultures by Pseudomonas putida GPo1 (ATCC 29347) and Cupriavidus necator (DSM 545) grown on octanoate and glucose, respectively.

RESULTS

Kinetic and stoichiometric equations, dependent on the specific growth rate of residual biomass (µR), were developed for carbon‐ and nitrogen‐limiting growth conditions. The parameters have biochemical significance and are independent of the biomass concentration. The results revealed that the Luedeking–Piret model is growth‐associated for both fermentations under carbon limitation. In addition, the PHA content increases with µR. Meanwhile, the PHA content is amplified under nitrogen limitation but decreases as μR increases. Also, the Luedeking–Piret model exhibits a profile that depends on the synthesized polyhydroxyalkanoate.

CONCLUSION

This study demonstrates that strategies for the production of PHAs require an in‐depth understanding of the process kinetics. This model gives satisfactory predictions, may be extended to fed batch cultures and may be adapted to other fermentations. © 2018 Society of Chemical Industry
HEV and HAV seroprevalence in men that have sex with men (MSM): An update from Milan, Italy
Authors: Greco Letizia , Uceda Renteria Sara C. , Guarneri Davide , Orlandi Anna , Zoccoli Antonella , Benardon Susanna , Cusini Marco , Lunghi Giovanna
Published: February 2018

Hepatitis E virus (HEV) is a feco‐orally transmitted pathogen and one of the most common cause of acute hepatitis worldwide. Recent studies in developed countries suggested that a direct human‐to‐human contact such as for sexually transmitted diseases may play a significant role in the HEV spread. The aim of this study was to investigate the seroprevalence of HEV and HAV in a group of MSM, including subjects HIV, and Treponema infected, in Milan, Italy. The overall anti HEV IgG seroprevalence in MSM was 10.2% (65/636), instead in the control group the detection rate was 5.2% (15/288) (P < 0.05); the anti HAV seroprevalence was 42.8% in MSM, when in the control group the positivity rate was 29.2% (P < 0.05). The rate of coinfection HEV/HAV was 14.6% in MSM and 1% in control group (P < 0.05). In the future, sexual history, HIV status, and STI risk might address specific investigations to prevent spread of pathogens such HEV in MSM, before becoming a substantial public health problem like for HAV outbreaks.
Anthropogenic impact in the Maya Lowlands of Petén, Guatemala, during the last 5500 years
Authors: Battistel D. , Roman M. , Marchetti A. , Kehrwald N. M. , Radaelli M. , Balliana E. , Toscano G. , Barbante C.
Published: February 2018

Trace and rare earth elements from a sediment core from Lake Petén Itzá (Guatemala) depict the geochemical dynamics affecting the lake from ∼5500 a BP to the present. This timing encompasses the Preclassic (4000–1700 a BP) and Classic Periods (1700−1000 a BP) when thriving Maya societies extensively cleared land for agriculture. We demonstrate that this land use occurred during times of increased precipitation, where both processes resulted in increased erosion. Rare earth element ratios depict high precipitation rates between 3000 and 1000 a BP, correlating with an increase in allochthonous silicate input and low organic carbon in the ‘Maya Clay’ stratigraphic section, where this layer is ascribed to intensive anthropogenic land use. Cesium anomalies provide additional evidence for runoff due to high rainfalls and amplified by anthropogenic impacts. The Petén Itzá core contains anomalous spikes of arsenic and mercury, and these peaks correspond to documented volcanic eruptions and therefore are probably natural. The geochemical composition of sediments and palynological records indicate re‐growth of the forest after ∼900 a BP. This increased forest vegetation coincides with the timing of the decline in Maya agriculture.
Multi‐proxy reassessment of the paleolimnology of Lake Bonneville (western USA) as observed in the restricted Pilot Valley sub‐basin
Authors: Nelson S. T. , Rey K. A.
Published: February 2018

Late Pleistocene sediments of pluvial Lake Bonneville of the western USA represent an important archive of climate and paleolimnological processes. Geochemical, mineralogical and diatom records from the Pilot Valley sub‐basin represent a complete multi‐proxy record of the Bonneville cycle, including closed‐basin transgressive, the Bonneville flood, open‐lake and closed‐basin regressive cycles. Diatoms record pH and salinity, and vary from alkalibiontic/brackish (early transgression), alkaliphilous/fresh‐brackish (deep lake) and back to alkalibiontic/brackish (late regression) conditions. Pennate diatoms reveal passage through and back into the euphotic zone due to the penetration of light through the water column supporting an active benthos. As such, the base of the euphotic zone (∼35 m depth) can be established through time. Restriction and evaporation within the Pilot Valley arm of Lake Bonneville during times of shallow water produced very high endogenic carbonate production, an order of magnitude higher than during deep water. This is shown by age–depth relations in the core, major element and isotopic variations, and sediment mineralogy, requiring a major re‐evaluation of the position of the Bonneville flood horizon within the sediments of Pilot Valley. In summary, lacustrine sediments from restricted arms of large pluvial lakes may vary significantly from complementary records from an open basin.
Lipidomic Analysis: From Archaea to Mammals
Authors: Řezanka Tomáš , Kolouchová Irena , Gharwalová Lucia , Palyzová Andrea , Sigler Karel
Published: February 2018

Lipids are among the most important organic compounds found in all living cells, from primitive archaebacteria to flowering plants or mammalian cells. They form part of cell walls and constitute cell storage material. Their biosynthesis and metabolism play key roles in faraway topics such as biofuel production (third‐generation biofuels produced by microorganisms, e.g. algae) and human diseases such as adrenoleukodystrophy, Zellweger syndrome, or Refsum disease. Current lipidomic analysis requires fast and accurate processing of samples and especially their characterization. Because the number of possible lipids and, more specifically, molecular species of lipids is of the order of hundreds to thousands, it is necessary to process huge amounts of data in a short time. There are two basic approaches to lipidomic analysis: shotgun and liquid chromatography–mass spectometry. Both methods have their pros and cons. This review deals with lipidomics not according to the type of ionization or the lipid classes analyzed but according to the types of samples (organisms) under study. Thus, it is divided into lipidomic analysis of archaebacteria, bacteria, yeast, fungi, algae, plants, and animals.
Extreme isomeric complexity of dissolved organic matter found across aquatic environments
Authors: Hawkes Jeffrey A. , Patriarca Claudia , Sjöberg Per J. R. , Tranvik Lars J. , Bergquist Jonas
Published: February 2018

The natural aquatic environment contains an enormous pool of dissolved reduced carbon, present as ultra‐complex mixtures that are constituted by an unknown number of compounds at vanishingly small concentrations. We attempted to separate individual structural isomers from several samples using online reversed‐phase chromatography with selected ion monitoring/tandem mass spectrometry, but found that isomeric complexity still presented a boundary to investigation even after chromatographic simplification of the samples. However, it was possible to determine that the structural complexity differed among samples. Our results also suggest that extreme structural complexity was a ubiquitous feature of dissolved organic matter (DOM) in all aquatic systems, meaning that this diversity may play similar roles for recalcitrance and degradation of DOM in all tested environments.
Effects of metabolic activity of sulphate‐reducing bacteria on heterogeneous corrosion behaviors of copper in seawater
Authors: Chen Shiqiang , Zhang Dun
Published: February 2018

In this paper, wire beam electrode method combined with other analysis methods, that is, electrochemical impedance spectroscopy, scanning electron microscope, and X‐ray photoelectron spectroscopy, was used to investigate effects of metabolic activity of sulphate‐reducing bacteria (SRB) on heterogeneous corrosion behaviors of copper in seawater. Results show that heterogeneous corrosion behaviors of copper are associated with metabolic activity of SRB, that is, the higher metabolic activity of SRB is, the more heterogeneously current of copper distributes. In particularly, on the 5th day of exposure, SRB cells on cathodic and anodic areas display distinct micromorphologies. SRB attach onto corrosion products film surface in anodic area, while they implant in corrosion products film with self‐produced organic nanowires in cathodic area. These organic nanowires may be conductive, and help SRB to obtain electrons from cathodic area directly. The XPS results show that the relative content of corrosion products components on cathodic area is obviously different with that on anodic area when SRB with the high metabolic activity are present.
Interactions of Desulfovibrio desulfuricans biofilm with 2205 duplex stainless steel – the role of microstructure
Authors: Michalska Joanna , Chmiela Bartosz , Simka Wojciech
Published: February 2018

The paper presents the results on sulfate‐reducing bacteria (SRB) induced corrosion of 2205 duplex stainless steel (DSS) in as‐received and thermally aged conditions. Biofilm formation and damage process stimulated by DSM642 strain were analyzed with reference to its metabolic activity and to the surface characterization of structure and configuration of the biofilm. Electrochemical techniques were applied to monitor bacterial attachment to the steel surface and to determine the effect of bacteria on the passivity and corrosion resistance of 2205 DSS. Results demonstrated that MIC behavior was strongly affected by the microstructure and phase composition of the steel. Enhanced biofilm interactions were mainly limited to the austenitic phase, as well as primary (γ) and intergranular (γ2) austenite was found to be more prone to bacterial attack. Thermal aging of 2205 DSS led to the enhanced bacterial attack. Thermally aged samples were characterized by quicker and more intensive biofouling. Pitting and crevice‐type attacks were predominant on the thermally aged samples. It has been found that the presence of DSM642 biofilm changed the corrosion mechanism of 2205 DSS in 3.5% NaCl and the SRB‐induced selective attack was evident even for the material in phase‐balanced conditions.
Characterizing Long Chain Branching in Polypropylene
Authors: Cangussú Manoela E. , de Azeredo Ana P. , Simanke Adriane G. , Monrabal Benjamin
Published: February 2018

In order to improve elongational viscosity of polypropylene, allowing its use in a wide range of applications, different samples of branched polypropylene have been produced by reactive extrusion and evaluated by different techniques. It is known that the long chain branching (LCB) can act as a nucleating agent in the crystallization process. This is confirmed by differential scanning calorimetry (DSC), optical microscopy, and crystallization analysis fractionation (CRYSTAF), where an increase in the crystallization temperature can be observed when comparing linear and branched samples. In the chemical composition distribution profile of the analyzed samples, it is possible to see differences in the amount of crystallized material among the branched PP samples and it is possible to correlate it with the long chain branching content and distribution, measured by Triple Detector Gel Permeation Chromatography (3D‐GPC), using the Mark‐Houwink plot (MH Plot), conformation plot, and gpcBR methodology. A decrease in dissolution temperature, and an increase in soluble fraction is observed by temperature rising elution fractionation (TREF) at increasing LCB content in the polymer samples. These results indicate that the presence, amount, or distribution of long chain branching affects the crystallization kinetics and the crystal morphology. CRYSTAF and TREF show a good correlation with LCB content measured by GPC.
Mathematical Modeling of Multiple High Temperature Thermal Gradient Interaction Chromatography (m‐HT‐TGIC) for Ethylene/1‐Olefin Copolymer Blends
Authors: Prasongsuksakul Siwakorn , Anantawaraskul Siripon , Soares João B. P.
Published: February 2018

High temperature thermal gradient interaction chromatography (HT‐TGIC) have been developed to measure the chemical composition distribution (CCD) of ethylene/1‐olefin copolymers over a wide range of compositions. Multiple high temperature thermal gradient interaction chromatography (m‐HT‐TGIC) is a concept developed to further enhance the physical separation of copolymer components by performing multiple adsorption/desorption cycles, similarly to the operation of multiple crystallization elution fractionation (m‐CEF) developed earlier. In this work, a mathematical model for describing m‐HT‐TGIC is developed based on population balances in multiple non‐equilibrium adsorption/desorption stages for ethylene/1‐olefin copolymer blends. The effects of number of m‐HT‐TGIC cycles, section length, and column length are also reported and discussed.
Biogeographical distribution of bacterial communities in Changbai Mountain, Northeast China
Authors: Han Dongxue , Wang Ning , Sun Xue , Hu Yanbo , Feng Fujuan
Published: February 2018

The broad‐leaved and Korean pine mixed forest in Changbai Mountain, China is an important component of boreal forest; the area is sensitive to global climate change. To understand spatial distribution patterns of soil bacterial community along elevation, we analyzed the soil bacterial community diversity and composition along an elevational gradient of 699–1177 m in a primitive Korean pine forest in Changbai Mountain using the high‐throughput sequencing. In total, 149,519 optimized sequences were obtained. Bacterial Shannon index increased along elevation from 699 m to 937 m and started to decrease at the elevation of 1,044 m, showing a humpback curve along elevation. Evenness (ACE index) and richness (Chao index) of the soil bacterial community both decreased with elevation (the highest values of 770 and 762 at 699 m and the lowest values of 548 and 539 at 1,177 m, respectively), all the indices are significantly different between elevations. Bacterial composition at phylum and genus levels had some differences between elevations, but the dominant bacterial populations were generally consistent. Beta‐diversity analysis showed a distance‐decay pattern of bacterial community similarity at different samples. Soil physical and chemical properties explained 70.78% of the variation in bacterial community structure (soil pH explained 19.95%), and elevational distance only explained 8.42%. In conclusion, the contemporary environmental disturbances are the critical factors in maintaining the bacterial spatial distribution compared with historical contingencies.
Development of a dual‐energy computed tomography quality control program: Characterization of scanner response and definition of relevant parameters for a fast‐kVp switching dual‐energy computed tomography system
Authors: Nute Jessica L. , Jacobsen Megan C. , Stefan Wolfgang , Wei Wei , Cody Dianna D.
Published: February 2018

Purpose

A prototype QC phantom system and analysis process were developed to characterize the spectral capabilities of a fast kV‐switching dual‐energy computed tomography (DECT) scanner. This work addresses the current lack of quantitative oversight for this technology, with the goal of identifying relevant scan parameters and test metrics instrumental to the development of a dual‐energy quality control (DEQC).

Methods

A prototype elliptical phantom (effective diameter: 35 cm) was designed with multiple material inserts for DECT imaging. Inserts included tissue equivalent and material rods (including iodine and calcium at varying concentrations). The phantom was scanned on a fast kV‐switching DECT system using 16 dual‐energy acquisitions (CTDIvol range: 10.3–62 mGy) with varying pitch, rotation time, and tube current. The circular head phantom (22 cm diameter) was scanned using a similar protocol (12 acquisitions; CTDIvol range: 36.7–132.6 mGy). All acquisitions were reconstructed at 50, 70, 110, and 140 keV and using a water‐iodine material basis pair. The images were evaluated for iodine quantification accuracy, stability of monoenergetic reconstruction CT number, noise, and positional constancy. Variance component analysis was used to identify technique parameters that drove deviations in test metrics. Variances were compared to thresholds derived from manufacturer tolerances to determine technique parameters that had a nominally significant effect on test metrics.

Results

Iodine quantification error was largely unaffected by any of the technique parameters investigated. Monoenergetic HU stability was found to be affected by mAs, with a threshold under which spectral separation was unsuccessful, diminishing the utility of DECT imaging. Noise was found to be affected by CTDIvol in the DEQC body phantom, and CTDIvol and mA in the DEQC head phantom. Positional constancy was found to be affected by mAs in the DEQC body phantom and mA in the DEQC head phantom.

Conclusion

A streamlined scan protocol was developed to further investigate the effects of CTDIvol and rotation time while limiting data collection to the DEQC body phantom. Further data collection will be pursued to determine baseline values and statistically based failure thresholds for the validation of long‐term DECT scanner performance.
A real‐time method to simultaneously measure linear energy transfer and dose for proton therapy using organic scintillators
Authors: Alsanea Fahed , Therriault‐Proulx Francois , Sawakuchi Gabriel , Beddar Sam
Published: February 2018

Purpose

Currently, no detectors are capable of simultaneously measuring dose and linear energy transfer (LET) in real time. In this study, we evaluated the feasibility of exploiting the difference in the response of various organic plastic scintillation detectors to measure LET and dose in therapeutic proton beams. The hypothesis behind this work was that the ratio of the responses of different scintillators exposed to the same proton beam can be used to obtain a LET vs ratio calibration curve that can then be used to infer LET under any other measurement conditions.

Methods

We first used similar scintillators with different ionization quenching factors. LET values for different irradiation conditions were calculated using a validated Monte Carlo model of the proton beam line. The quenching factors in the Birks equation for different scintillators as a function of LET were obtained from measurements in a 100‐MeV pristine proton beam. We then used four different organic scintillation materials — polystyrene (BCF‐12), poly (methyl methacrylate), polyvinyltoluene, and a liquid scintillator — for which the LET response varied with regard to not only quenching but also differences in material density and relative stopping power. We simultaneously exposed the four different organic scintillators and a plane–parallel ion chamber to passively scattered proton beams at fluence‐averaged LET. Comparisons to the expected values obtained from the Monte Carlo simulations were made on the basis of both dose and LET.

Results

The maximum difference in the quenching factor was 20%, resulting in a 5% change in LET with a response ratio over a range of 5 keV/μm. Among all the scintillators investigated, the ratio of PMMA to BCF‐12 provided the best correlation with LET values and was therefore used to construct the LET calibration curve. The expected LET values in the validation set were within 2% ± 6%, which resulted in dose accuracy of 1.5% ± 5.8% for the range of LET values investigated in this work.

Conclusions

We demonstrated the feasibility of using the ratio of the light outputs of two organic scintillators to simultaneously measure LET and dose in therapeutic proton beams for fluence‐averaged LET values from 0.47 to 1.26 keV/μm. Further studies are needed to verify the response for higher LET values and the reproducibility of this method.
Buckling‐Induced Assembly of Three‐Dimensional Tunable Metamaterials
Authors: Zhou Shiwei , Xie Yi Min , Lin Sen , Feng Xi‐Qiao , Li Qing
Published: February 2018

Conventional metamaterials are usually confined to planar settings due to the fabrication challenges at the nanoscale. Here, we explore the shape transformation of metasurfaces into three‐dimensional metamaterials to generate some on‐demand plasmon modes which would be otherwise unachievable in two dimensions. This method is inspired by the buckling‐induced folding of a layer of metal sheet bonded to a stretchable compliant substrate in some specified regions. Two prototypes of three‐dimensional metamaterials are obtained, demonstrating the enhancement of quality factors as well as the tunability. We find the occurrence of sharp Fano resonance and the resonance mode with toroidal dipole attributed to the structural asymmetry in depth. This work provides an effective approach to practical fabrication of nanoscale metamaterials in an extra dimension that would enable a wide range of applications in the optical spectrum.
Drivers of interannual variability of the East African “Long Rains”
Authors: Vellinga Michael , Milton Sean F.
Published: February 2018

The East African Long Rains season is unusual in that its year‐to‐year rainfall variability is mostly insensitive to the main modes of interannual tropical sea‐surface temperature (SST) variability (ENSO, Indian Ocean Dipole). Various alternative drivers of interannual variability have been described previously but remain poorly understood. Here we present an analysis of three important drivers: regional Indian Ocean SST, seasonal amplitude of the Madden–Julian Oscillation (MJO) and phase of the Quasi‐Biennial Oscillation (QBO). Reanalyses and instrumental datasets are in close agreement about rainfall interannual variability across the region as a whole, which represents 30–50% of the total variance. Subregional structure of the remaining variance is far more uncertain and is not considered here. We use modern reanalyses to understand how the proposed drivers affect March–April mean. Common to all three drivers is their ability to modify the large‐scale subsidence over the East African region during boreal spring. SST in the western Indian Ocean achieves this via anomalous boundary‐layer heating of the lower troposphere. The MJO modifies subsidence over the region through anomalous ascent and descent. Rainfall over East Africa responds to this MJO forcing in a unidirectional way, allowing seasonal rectification and interannual modulation by seasonal MJO amplitude. Understanding the QBO's influence is complicated by the limited number of cycles over the reanalysis period. Each driver individually has a modest effect on the Long Rains, but added together they explain 30–60% of the variance of yearly rainfall variability that affects the region as a whole. This constitutes 13–25% of the total interannual precipitation variance, depending on dataset. The mechanisms we discuss suggest priorities for model development to improve model variability over East Africa. The metrics developed here lend themselves for easy evaluation of the remote drivers in models and other datasets.
Critical airway compression caused by a large mediastinal tumour with spontaneous haemorrhage
Authors: Liu Shih‐Peng , Chien Hung‐Che , Chen Chun‐Ku , Hsieh Chih‐Cheng , Huang Chien‐Sheng
Published: February 2018

We report the case of a 77‐year‐old woman presenting with out‐of‐hospital cardiac arrest, which was then interpreted as an acute, life‐threatening critical airway compression by a huge mediastinal tumour without appropriate diagnosis. Emergency extracorporeal membrane oxygenation was cannulated for sufficient respiratory support after spontaneous circulation was regained. After the multidisciplinary team, involving thoracic surgeons, discussed the resectability of the mediastinal tumour, the patient underwent successful resection of the mediastinal tumour through a median sternotomy. The pathological report demonstrated an intrathoracic goitre with spontaneous haemorrhage and haematoma formation, and the patient was discharged with favourable respiratory and neurological outcomes.
Thin laryngeal foreign bodies in infants: diagnostic potential of MDCT
Authors: Concerto Antonella , Cavallaro Marco , Visalli Carmela , Bagnato Anna Maria , Barbaro Ugo , Salamone Ignazio
Published: February 2018

A laryngeal foreign body (FB) is a significant, life‐threatening event in the paediatric population. Incomplete airways obstruction by a thin, laminar, radiolucent FB lodged in the glottis or supraglottis is a rare occurrence that may present with non‐specific symptoms, absence of chest findings, and normal radiographic investigations, resulting in misdiagnosis, delay in diagnosis, or prolonged recovery. We report two cases of 10‐month‐old male infants, each with a thin radiolucent FB lodged between the vocal folds that was detected with low‐dose multidetector computed tomography (MDCT) and thin‐slice reconstruction. Both infants presented with symptoms of respiratory airway inflammation at clinical examination and negative neck and chest radiographs. FBs were removed by direct laryngoscopy, without complications. In our experience, low‐dose MDCT with thin‐slice reconstruction is particularly useful for diagnosis in cases of suspected FB aspiration with uncertain clinical presentation and negative radiographic exams.