bluuebunny/crossref_metadata_2025 huggingface dataset:
Generation I(mmersion) – How to Meet Learner Expectations of Tomorrow
Authors: Erenli Kai
Published: April 2016

Today’s teachers mainly belong to the so-called “Generation X” while learners are most often described as “Generation Y” or “Millennials”. Most current discussions of learning methods are being held in view of the status quo. But what about the learners of tomorrow? What expectations do the learners of tomorrow have? Which methods and tools will the teachers of tomorrow have in stock to meet these expectations? “The old learning spaces, dominated by the immensely successful organizations of the industrial era like schools and universities, are struggling to maintain authority and control over the definition and certification of knowledge while at the same time remaining true to the stated mandate of helping to equip people and society for a life where learning is much more heterogeneous and heterarchical”[11]. Therefore, wouldn´t it be good to have a toolset ready and be able to choose the appropriate tools and techniques right on time? Reflecting on publications, expert interviews and state-of-the-art best practices, this paper attempts to draw a picture of the future (e-)learning scenario. To give the next generation a name, “Generation I(mmersion)” has been chosen. Despite breaking the X, Y, Z sequence, this name highlights the state of “Immersion”, which educators and learners of tomorrow will/might find themselves in.
Experimental Investigation of Residual Stress in the Concrete Caused by Volume Changes with Consideration of Environmental Effect
Authors: Zvolánek Lukáš , Terzijski Ivailo , Kratochvíl Miroslav , Kadlec Jaroslav
Published: April 2016

This paper investigates such concrete properties which determine the stress magnitude of concrete caused by its volume changes. The magnitude of induced stress is given by shrinkage or swelling value and corresponding modulus of elasticity value. It is essential to know these properties of concrete from the beginning of its skeletal frame formation since the volume changes occur almost immediately after mixing of water with cement. In addition, the humidity effect of ambient environment when the early age concrete matured was considered. Thereby was achieved relevant comparison between ordinary concrete mixture and optimized one. For experiments was used micro-concrete (with maximum aggregate size 1.6 mm) with respect to cost reduction. After the suitable composition of micro-concrete was found the analogue investigation was carried out with the optimized concrete.
Effect of Density on Compressive Strength of Ultra High Performance Fiber Reinforced Concrete (UHPFRC) Using Design of Experiment
Authors: Mosaberpanah Mohammad Ali , Eren Ozgur
Published: April 2016

This paper aims to model the effect of density in 7, 14, 28 days on compressive strength of Ultra High Performance Concrete (UHPC) in same compaction and curing conditions by Design of Experiments (DOE) methodology using vary range of 5 variables: Silica fume (SF), Steel Fiber, Cement 42.5, Superplasticizer (SP), and water cemetiotious ratio (w/c).The results shows the significance effect of density on compressive strength of UHPC in different days, The models are valid for the mixes made with 1.0 sand, 0.15-0.30 silica fume amount, 0.70-1.30 cement amount, 0.10- 0.20 steel fiber, 0.04- 0.08 superplasticizer (all values are by sand by weight mass) and 0.18- 0.32 water cementitious ratio.
Research of Fire Resistance of Tunnel Lining Concrete
Authors: Hubáček Adam , Ondryášová Veronika
Published: April 2016

The article is involved with study of fire resistance of concrete for tunnel linings. It summarises the problems of present knowledge of concrete resistance in tunnels and deals with behaviour of concrete particular parts at exposure to high temperatures. Further possibilities of fire resistance improvement for production of concretes together with fire prevention are described in this paper.
Evaluation of Wedge Splitting Fracture Tests Using the Double-K Model: Analysis of the Effect of Hemp Fibre Dosage and Length in Concrete Specimens
Authors: Šimonová Hana , Havlíková Ivana , Sobek Jakub , Abdulrahman Alaa , Keršner Zbyněk , Merta Ildikó
Published: April 2016

This paper deals with the results obtained from the employment of a selected fracture model to evaluate wedge splitting fracture tests carried out on hemp fibre concrete specimens. The research work was focused mainly on the effect of the dosage and length of hemp fibres on the initiation part of crack propagation in concrete specimens, and on critical crack opening displacement. Concrete mixtures with different volumetric dosages (0.5, 1.0 and 2.0 %) and fibre lengths (10, 20 and 40 mm) were prepared, and six identical specimens were cast from each mixture. Specimens were also cast from a reference mixture, which was without fibres. The specimens were provided with an initial notch and tested using the wedge splitting test method. Load versus crack mouth opening displacement diagrams were recorded during testing and (after data filtering and appropriate modifications) subsequently evaluated using the Double-K fracture model. This model allows the evaluation of two material parameters – the initiation fracture toughness, which defines the onset of stable crack propagation, and the unstable fracture toughness, which defines the onset of unstable cracking or failure. Finally, the critical crack opening displacement was determined with the assumption of the bilinear function of softening in tension.
Numerical Modeling of Reinforcement Corrosion on Bond Behaviour
Authors: Holly Ivan , Bilčík Juraj , Gajdošová Katarína
Published: April 2016

Chloride-induced steel corrosion is one of the major deterioration problems for steel reinforced concrete structures. Its effects on RC structures include cracking of the concrete cover, reduction and eventually loss of bond between concrete and corroding reinforcement, and reduction of cross-sectional area of reinforcing steel. The accumulated corrosion products on the bar surface cause longitudinal cracking of the concrete cover. Loss of concrete cover leads to reduction in bond strength at the interfacial zone between the two materials. In addition, the deterioration of the ribs of the deformed bars causes a significant reduction of the interlocking forces between the ribs of the bars and the surrounding concrete keys. This deteriorates the primary mechanism of the bond strength between deformed bars and concrete, and hence, the bond strength decreases significantly. In this paper the effect of reinforcement corrosion on the bond strength between reinforcement and concrete was investigated for different corrosion levels. The effect of corrosion was simulated by the nonlinear numerical analysis with the FEM program using the 3D models.
Experimental Analysis of Slender Concrete Columns at the Loss of Stability
Authors: Kendický Peter , Benko Vladimír , Gúcky Tomáš
Published: April 2016

The use of non-linear methods for design of slender concrete columns by European standards. For the verification of non-linear design methods it is important to compare their results with results of experiments. Within the applied research of the Faculty of Civil Engineering at Slovak University of Technology in Bratislava in cooperation with the company ZIPP Bratislava LTD the experimental verification of the slender reinforced concrete columns was realized. In the paper the authors present the preparation and process one of three series of slender reinforced concrete columns, which were made to verify the reliability of various design methods. Columns of planned second series were designed from high performance concrete C100/115, but the material tests showed that the strength class of concrete was C70/85. The columns, subjected to axial force and bending moment were designed to fail due to loss of stability before the resistance of the critical cross-section is reached. The expected compressive strain in concrete was 1,5 ‰.
Dynamic Characteristics of Multi-Story Reinforced Concrete Buildings
Authors: Snaebjornsson Jónas Thór , Thorhallsson Eythor Rafn
Published: April 2016

Having a realistic estimate of structural parameters, such as natural frequency and damping is important for design purposes. In this study, available wind and earthquake induced acceleration data from four multi-story reinforced concrete buildings are utilized to examine structural behaviour and system parameters. The buildings measurement systems are described and the recorded structural response data presented. The data stems from two different sources of excitation, i.e. wind and earthquake, and are recorded for various excitation levels and environmental conditions. System identification analyses of the buildings are carried out applying previously verified parametric methods to the recorded data. The natural frequencies and critical damping ratios established from the recordings are compared to values estimated using design guidelines and international data compilations for reinforced concrete structures of similar type. Considerable variability is discovered between the different estimation formulas and the observed natural frequencies of the buildings are found to lie at the upper limit of the prediction formula.
Experimental Research into Demountable Joints of a Precast System
Authors: Witzany Jiří , Čejka Tomáš , Karas Jiří , Polák Aleš , Zigler Radek
Published: April 2016

The TA02010837 project "Multipurpose dismantleable prefabricated reinforced concrete building system with controlled joint properties and the possibility of repeated use " includes the development of a multi-purpose reinforced concrete precast system with demountable joints. The novel concept of the reinforced concrete precast structure brings numerous innovative, not yet verified solutions, construction and structural problems, functional requirements and user qualities. Apart from theoretical and numerical analyses, a component part of the research is demanding and extensive experimental research into the load-bearing system’s structural members and nodes, including the verification of the hybrid prototype implementation system in which the basic versions of the presumed system alternatives are applied – a column, pillar, wall, integrated system and a system composed of open spatial wall units.
Effects of Axial Stress on Air Permeability of HPFRC
Authors: Paulík Peter , Hudoba Igor , Ševčík Patrik
Published: April 2016

Gas permeability of concrete is a property, which is recognized as one of the basic indicators of its durability. Measuring of the air permeability is mostly carried out on samples, which are not exposed (before or during the tests) to any certain external loads, which could cause microcracks in hardened cement matrix. However, in the case of real structures there is always some stress level and thus the concrete permeability is usually affected by microcracks. To know both, permeability of sound concrete and the permeability of concrete containing certain amount of microcracks, is the basic assumption for correct evaluation of its durability. Our paper deals with the permeability of loaded specimens made of high performance fibre reinforced concrete (HPFRC). This type of concrete is in Slovakia used for the construction of containers for a low and medium level radioactive waste storage and thus their properties in loaded conditions are of primary concern. Permeability was measured with Torrent Permeability Tester on cube specimens at different loading levels and after unloading. Specimens were 10 years old and varied in the amount of fibre reinforcement.
Rendezvous Point Technique for Multivehicle Mine Countermeasure Operations in Communication-Constrained Environments
Authors: Yordanova Veronika , Griffiths Hugh
Published: April 2016

AbstractAdvantages of using a multivehicle network over a single autonomous underwater vehicle platform include extended coverage area, potential cost and time efficiency, and more robust performance. A common issue that slows advancement in the field is the limited available
communication between the platforms. The approach we propose is based on assigning a sequence of rendezvous points (RPs) where the vehicles can meet and exchange information. The work we present in this paper applies principally to mine countermeasure and suggests that, despite the disadvantage
of time to allow for the vehicles to reach the RPs, there are techniques that can minimize the losses and provide advantages such as easier coordination and access points for operator monitoring and system modifications. The results we present in this paper give an estimate of the reduction
in loss if such an approach is employed. We make a comparison between the RP and a benchmark case by analyzing numerical simulations.
Results of the first Wave Glider experiment in the southern Tyrrhenian Sea
Authors: Aulicino Giuseppe , Cotroneo Yuri , Lacava Teodosio , Sileo Giancanio , Fusco Giannetta , Carlon Ryan , Satriano Valeria , Pergola Nicola , Tramutoli Valerio , Budillon Giorgio
Published: April 2016

A wave-propelled autonomous vehicle (Wave Glider) instrumented with a variety of oceanographic and meteorological sensors was launched from Gulf of Naples on the 12th of September 2012 for a two-week mission in the Southern Tyrrhenian Sea. The main objective of the mission was a preliminary evaluation of the potential of commercial autonomous platforms to provide reliable measurements of sea surface parameters which can complement existing satellite based products moving from the local to the synoptic scale. To this aim Wave Glider measurements were compared to equivalent, or near-equivalent, satellite products achieved from MODIS (Moderate Resolution Imaging Spectroradiometer) sensors onboard the EOS (Earth Observing System) satellite platforms and from AVISO (Archiving Validation and Interpretation of Satellite Oceanographic Data). Level-3 near real time and Level-4 reprocessed sea surface foundation temperature products provided by the CMEMS (Copernicus Marine Environment Monitoring Service) were also included in this study as well as high resolution model output supplied by NEMO (Nucleus for European Modelling of the Ocean). The Wave Glider was equipped with sensors to measure temperature, salinity, currents, as well as Colored Dissolved Organic Matter (CDOM), turbidity and refined fuels fluorescence. The achieved results confirmed the emerging value of Wave Gliders in the framework of multiplatform monitoring systems of the ocean surface parameters. In particular, they showed that Wave Glider measurements captured the southern Tyrrhenian Sea major surface oceanographic features, including the coast to open sea haline gradient and the presence of a cyclone-anticyclone system in the southeastern sub-region. The Wave Glider also had the capability to monitor upper ocean currents at finer spatial and temporal scales than satellite altimetric observations and model outputs. Nonetheless, results stressed the existence of several limits in the combined use of satellite and Wave Glider observations and the necessity of further analyses concerning the monitoring of the ocean optical properties. In fact, Wave Glider and satellite-based products agree in terms of sea surface temperature and currents patterns, while bio-optical properties turned out to be less well correlated. No significant traces of refined fuels have been detected along the WG track.
О принципе усреднения в периодической по времени задаче для уравнений Навье-Стокса с быстро осциллирующей массовой силой
Authors: Khatskevich Vladimir Lvovich
Published: April 2016

Исследуется поведение множества периодических по времени решений
трехмерной системы уравнений Навье-Стокса в ограниченной области
при стремлении частоты колебаний правой части к бесконечности.
Установлено, что множество периодических решений стремится
к множеству решений усредненного стационарного уравнения.
Библиография: 14 названий.
Primary Care Physician Designation and Response to Clinical Decision Support Reminders
Authors: Gorman Paul , Weinfeld Jeffrey
Published: April 2016

Clinical decision support (CDS) has been shown to improve process outcomes, but overalerting may not produce incremental benefits. We analyzed providers’ response to preventive care reminders to determine if reminder response rates varied when a primary care provider (PCP) saw their own patients as compared with a partner’s patients. Secondary objectives were to describe variation in PCP identification in the electronic health record (EHR) across sites, and to determine its accuracy.

We retrospectively analyzed response to preventive care reminders during visits to outpatient primary care sites over a three-month period where an EHR was used. Data on clinician requests for reminders, viewing of preventive care reminders, and response rates were stratified by whether the patient visited their own PCP, the PCP’s partner, or where no PCP was listed in the EHR. We calculated the proportion of PCP identification across sites and agreement of identified PCP with an external standard.

Of 84,937 visits, 58,482 (68.9%) were with the PCP, 10,259 (12.1%) were with the PCP’s partner, and 16,196 (19.1%) had no listed PCP. Compared with PCP partner visits, visits with the patient’s PCP were associated with more requested reminders (30.9% vs 22.9%), viewed reminders (29.7% vs 20.7%), and responses to reminders (28.7% vs 12.6%), all comparisons p<0.001. Visits with no listed PCP had the lowest rates of requests, views, and responses. There was good agreement between the EHR-listed PCP and the provider seen for a plurality of visits over the last year (D = 0.917).

A PCP relationship during a visit was associated with higher use of preventive care reminders and a lack of PCP was associated with lower use of CDS. Targeting reminders to the PCP may be desirable, but further studies are needed to determine which strategy achieves better patient care outcomes.

primary care physician (PCP), clinical decision support (CDS), electronic health record (EHR), National Provider Identifier (NPI)
Restauración de la ornamentación dorada Salas nobles del palacio del Barón de Ariza
Authors: González M. Alonso Enriqueta
Published: April 2016

Sin resumen
Recording of climate and diagenesis through sedimentary DNA and fossil pigments at Laguna Potrok Aike, Argentina
Authors: Vuillemin Aurèle , Ariztegui Daniel , Leavitt Peter R. , Bunting Lynda ,   the PASADO Science Team
Published: April 2016

Abstract. Aquatic sediments record past climatic conditions while providing a wide range of ecological niches for microorganisms. In theory, benthic microbial community composition should depend on environmental features and geochemical conditions of surrounding sediments, as well as ontogeny of the subsurface environment as sediment degraded. In principle, DNA in sediments should be composed of ancient and extant microbial elements persisting at different degrees of preservation, although to date few studies have quantified the relative influence of each factor in regulating final composition of total sedimentary DNA assemblage. Here geomicrobiological and phylogenetic analyses of a Patagonian maar lake were used to indicate that the different sedimentary microbial assemblages derive from specific lacustrine regimes during defined climatic periods. Two climatic intervals (Mid-Holocene, 5 ka BP; Last Glacial Maximum, 25 ka BP) whose sediments harbored active microbial populations were sampled for a comparative environmental study based on fossil pigments and 16S rRNA gene sequences. The genetic assemblage recovered from the Holocene record revealed a microbial community displaying metabolic complementarities that allowed prolonged degradation of organic matter to methane. The series of Archaea identified throughout the Holocene record indicated an age-related stratification of these populations brought on by environmental selection during early diagenesis. These characteristics were associated with sediments resulting from endorheic lake conditions and stable pelagic regime, high evaporative stress and concomitant high algal productivity. In contrast, sulphate-reducing bacteria and lithotrophic Archaea were predominant in sediments dated from the Last Glacial Maximum, in which pelagic clays alternated with fine volcanic material characteristic of a lake level highstand and freshwater conditions, but reduced water column productivity. Comparison of sedimentary DNA composition with that of fossil pigments suggested that post-depositional diagenesis resulted in a rapid change in the initial nucleic acid composition and overprint of phototrophic communities by heterotrophic assemblages with preserved pigment compositions. Long DNA sequences (1400–900 bp) appeared to derive from intact bacterial cells, whereas short fragments (290–150 bp) reflected extracellular DNA accumulation in ancient sediments. We conclude that sedimentary DNA obtained from lacustrine deposits provides essential genetic information to complement paleoenvironmental indicators and trace post-depositional diagenetic processes over tens of millennia. However, it remains difficult to estimate the time lag between original deposition of lacustrine sediments and establishment of the final composition of the sedimentary DNA assemblage.
Assessment of combating-desertification strategies using the linear assignment method
Authors: Sadeghravesh Mohammad Hassan , Khosravi Hassan , Ghasemian Soudeh
Published: April 2016

Abstract. Nowadays desertification, as a global problem, affects many countries in the world, especially developing countries like Iran. With respect to increasing importance of desertification and its complexity, the necessity of attention to the optimal combating-desertification alternatives is essential. Selecting appropriate strategies according to all effective criteria to combat the desertification process can be useful in rehabilitating degraded lands and avoiding degradation in vulnerable fields. This study provides systematic and optimal strategies of combating desertification by use of a group decision-making model. To this end, the preferences of indexes were obtained through using the Delphi model, within the framework of multi-attribute decision making (MADM). Then, priorities of strategies were evaluated by using linear assignment (LA) method. According to the results, the strategies to prevent improper change of land use (A18), development and reclamation of plant cover (A23), and control overcharging of groundwater resources (A31) were identified as the most important strategies for combating desertification in this study area. Therefore, it is suggested that the aforementioned ranking results be considered in projects which control and reduce the effects of desertification and rehabilitate degraded lands.
УЛААНБААТАР ХОТЫН ГЭР ХОРООЛЛЫН НҮҮРСНИЙ ҮНСНИЙ ШИНЖ ЧАНАР, АШИГЛАХ БОЛОМЖИЙН УРЬДЧИЛСАН СУДАЛГАА
Authors: Даваабал Б , Батцэцэг Б , Золзаяа Ц , Тэмүүжин Ж
Published: April 2016

Улаанбаатар хотын гэр хороололд хэрэглэгдэж байгаа зарим ордын нүүрснээс гарч буй үнсний химийн найрлага, дагалдах элемент, цацраг идэвхи болон эрдэс бүрдлийн судалгааг нарийвчлан явуулав. Судалгаанд Налайх, Багануурын ордын хоёр төрлийн нүүрсийг ердийн болон бүрэн шаталттай төслийн гэсэн хоёр төрлийн зууханд шатааж гаргасан үнсийг ашиглав. Бэлдсэн үнсний шатаалтын  хорогдол нь 8.90-14.07%-ийн хооронд хэлбэлзэж байв. Рентгенфлуоросцентийн (XRF) судалгаагаар Налайх, Багануурын нүүрсний үнс нь С ангиллын буюу лигнит нүүрсний үнс болох нь тогтоогдсон. Судалгаанд авсан хаягдал үнсүүд дэх Калий, Торийн изотопын идэвхжлийн хэмжээ дэлхийн дунджаас бага  байсан боловч Радийн изотопын идэвхжлийн хэмжээ өндөр байв. Үнсний 98 хүртэлх хувийн ширхэглэл нь 73 микроноос том хэмжээтэй байсан. Үнсний голлох эрдсүүд нь кварц (SiO2), шохой (CaCO3), aнгидрит (CaSO4) болохыг рентгендифрактометрийн (XRD)  судалгаагаар тогтоолоо. Үнсэнд Метилен хөх (66мг/г) болон Иодыг (3.06 %) шингээх замаар шингээлтийн багтаамж тодорхойлов.
ЗАРИМ ТУСГАЙ РАДИКАЛЫН ТУХАЙ
Authors: Төмөрбат С
Published: April 2016

Энэхүү өгүүлэлд Амицур цагираг, уламжлагдах Амицур цагиргийн тухай судалсан бөгөөд радикал t -ийн анхдагч цагираг А бүр нь уламжлагдах Амицурын биш байх сонирхолтой радикалыг байгуулж судалсан юм.
УЛААНБААТАР ХОТЫН СУУРЬШЛЫН БҮСИЙН ХӨРСНИЙ БОХИРДЛЫН СУДАЛГААНЫ ЗАРИМ ДҮН
Authors: Сономдагва Ч , Бямбацэрэн Ч , Даваадорж Д
Published: April 2016

Энэхүү судалгааны ажлын хүрээнд Улаанбаатар хотын хөрсний бохирдлыг өнгөн хөрсөн дэх зарим хүнд металл болон өнгөн хөрсний цацраг идэвхийн агууламжаар судлан тэдгээрийн тархалтын зураглалыг хийж гүйцэтгэлээ. Хөрсний бохирдлыг судлахын тулд Улаанбаатар хотын суурьшлын бүсийн газрын гадаргаас жигд бус байдлаар, бохирдолтонд шууд өртөхгүй, хуримтлал үүсэхгүй газруудыг сонгон авч хөрсний бохирдлыг хүнд металл болон цацраг идэвхийн түвшнээр тодорхойлон үр дүнг гарган авсан. Хөрсний цацраг идэвхийн хэмжээ, хүний эрүүл мэндэд нөлөөлөх байдал зэргийг тооцохдоо A.A.Qureshi-ийн томъёогоор тооцож үзэхэд хавдраар өвчлөх эрсдлийг тооцоолсон бөгөөд судалгааны дүн 0.6-1.34*10-3 хооронд хэлбэлзэж байна. Уг аргачлал нь цацраг идэвхт изотопын хэмжээ болон гадаад, дотоод идэвх, нийлбэр бохирдолт, эрүүл мэндэд үзүүлэх эрсдэл зэргийг тооцдог учраас бусдаасаа давуу талтай юм. Судалгааны үр дүнгээс үзэхэд, Rаeq буюу цацраг идэвхт изотопын суурь агууламжийн хувьд Хүрэл тогоот, Нисэх орчимд изотопын суурь агууламж хамгийн их буюу 138-152 Bq/kg-1, харин 100 айл, Да хүрээ орчмоор хамгийн бага утга буюу 70.3-95.8 Bq/kg-1 орчим агууламжтай гарсан байна.Хөрсний хүнд металлын бохирдлыг судлаж, индексээр илэрхийлэхэд Улаанчулуут, Цагаандаваа, Хайлааст орчим хамгийн их бохирдолттой байгаа бөгөөд бохирдуулагч элементүүдээс хүнцлийн агууламж ЗДХ-ний аюултай агууламжинд хүрсэн үзүүлэлттэй байгаа нь анхаарах шаардлагатай асуудал юм. Цацраг идэвхийн хувьд, хотын өмнөд талаар хамгийн өндөр бохирдолттой байгаа хэдий ч судлаачдын гаргасан дүгнэлтээр хүний эрүүл мэндэд сөрөг нөлөө үзүүлэх хэмжээнд хүрээгүй байна.
Sub 10 ns fast switching and resistance control in lateral GeTe-based phase-change memory
Authors: Yin You , Zhang Yulong , Takehana Yousuke , Kobayashi Ryota , Zhang Hui , Hosaka Sumio
Published: April 2016

In this study, we investigated the fast switching and resistance control in a lateral GeTe-based phase-change memory (PCM). The resistivity of GeTe as a function of annealing temperature showed that it changed by more than 6 orders of magnitude in a very narrow temperature range. X-ray diffraction patterns of GeTe films indicated that GeTe had only one crystal structure, that is, face-centered cubic. It was demonstrated that the lateral device with a top conducting layer had a good performance. The operation characteristics of the GeTe-based lateral PCM device showed that it could be operated even when sub-10-ns voltage pulses were applied, making it much faster than a Ge2Sb2Te5-based device. The device resistance was successfully controlled by applying a staircase-like pulse, which enables the device to be used for fast multilevel storage.
The Histopathologic Effects of l-Carnitine in a Sodium Taurocholate–Induced Severe Pancreatitis Model
Authors: Karakahya Murat , Gül Mehmet , Işık Sevil , Aydın Cemalettin , Yiğitcan Birgül , Otan Emrah , Taner Orug
Published: April 2016

This study aims to evaluate the histopathologic effects of l-carnitine (LC) in an experimental severe pancreatitis (SP) model induced with sodium taurocholate. LC is an amino acid–like molecule that plays an active role in transporting fatty acids and producing acetyl CoA in mitochondrial matrix for β-oxidation to provide energy that is needed for metabolism. It has ameliorative effects on cell injury, as has been demonstrated in many studies. The present study focuses on evaluating the histopathologic effects of LC in an experimental SP model. A total of 32 Sprague-Dawley male rats were divided into 4 groups in a randomized fashion: control (C) group, l-carnitine (LC) group, pancreatitis (P) group, and pancreatitis and l-carnitine (P + LC) group. Pancreatitis was induced by a retrograde pancreatic duct injection of 4% sodium taurocholate, and LC was administered 200 mg/kg/d in the treatment group. Rats were euthanized with cardiac puncture under anesthesia at the 48th hour of the experiment for biochemical and histopathologic examination. In the P + LC group, the histopathologic findings of the pancreatitis were markedly reduced. Acinar cell degeneration was rarely seen. Interlobular and intralobular inflammation and edema was generally mild. The pancreatic damage score of the P + LC group was significantly lower than that of the P group (P < 0.05). This study revealed that LC has a significant histopathologic protective effect on acinar cell degeneration in a sodium taurocholate–induced SP model in rats.
Characteristics of GPS TEC variations in the polar cap ionosphere
Authors: Watson Chris , Jayachandran P. T. , MacDougall John W.
Published: April 2016

This paper presents statistical characteristics (occurrence rate, amplitude, and frequency) of low‐frequency (<100 mHz) variations in total electron content (TEC) observed in the polar cap ionosphere. TEC variations were primarily associated with mesoscale (tens to hundreds of kilometers) ionization structures and were observed by five Global Positioning System (GPS) receivers over a 6 year period (2009–2014). The altitude of ionization structures was estimated by using colocated ionosonde radars. High data rate receivers combined with broad spatial coverage of multisatellite TEC measurements provided high‐resolution magnetic local time/latitude maps of TEC variation characteristics, which were examined as a function of solar cycle and season. These high‐resolution maps improve upon the current observational picture of mesoscale structuring in the polar cap and provide accurate links to particular magnetospheric source regions. Occurrence of TEC variations was consistently highest in dayside regions mapping to low latitude and plasma mantle boundary layers, while largest‐amplitude TEC variations were observed in dayside regions close to the polar cusp, and lower latitudes around midnight. Occurrence and amplitude of TEC variations increased significantly during the ascending phase of the solar cycle, independent of solar wind conditions, while seasonal statistics showed highest dayside occurrence and amplitude in winter months, lowest in summer, and highest nightside occurrence and amplitude around equinox. A surprising result in the frequency distributions of TEC variations was discrete frequencies of about 2 and 4 mHz, which appeared to originate from regions corresponding to the plasma mantle, immediately poleward of the polar cusp.
Combination of various observation techniques for regional modeling of the gravity field
Authors: Lieb Verena , Schmidt Michael , Dettmering Denise , Börger Klaus
Published: April 2016

Modeling a very broad spectrum of the Earth's gravity field needs observations from various measurement techniques with different spectral sensitivities. Typically, high‐resolution regional gravity data are combined with low‐resolution global observations. To exploit the gravitational information as optimally as possible, we set up a regional modeling approach using radial spherical basis functions, emphasizing the strengths of various data sets by the flexible combination of high‐ and middle‐resolution terrestrial, airborne, shipborne, and altimetry measurements. The basis functions are defined and located in the region of interest in such a manner, which the highest measure of information of the input data is captured. Any functional of the Earth's gravity field can be derived, as, e.g., quasi‐geoid heights or gravity anomalies. Here we present results of a study area in Northern Germany. A comprehensive cross validation to external observation data delivers standard deviations less than 5 cm. Differences to an existing regional quasi‐geoid model count on average ±6 cm and proof the plausibility of our solution. The comparison with existing global models reaches higher standard deviations for the more sensitive gravity anomalies as for quasi‐geoid heights, showing the additional value of our solution in the high frequency domain. Covering a broad frequency spectrum, our regional models can be used as basis for various applications, such as refinement of global models, national geoid determination, and detection of mass anomalies in the Earth's interior.
Estimating nocturnal opaque ice cloud optical depth from MODIS multispectral infrared radiances using a neural network method
Authors: Minnis Patrick , Hong Gang , Sun‐Mack Szedung , Smith William L. , Chen Yan , Miller Steven D.
Published: April 2016

Retrieval of ice cloud properties using IR measurements has a distinct advantage over the visible and near‐IR techniques by providing consistent monitoring regardless of solar illumination conditions. Historically, the IR bands at 3.7, 6.7, 11.0, and 12.0 µm have been used to infer ice cloud parameters by various methods, but the reliable retrieval of ice cloud optical depth τ is limited to nonopaque cirrus with τ < 8. The Ice Cloud Optical Depth from Infrared using a Neural network (ICODIN) method is developed in this paper by training Moderate Resolution Imaging Spectroradiometer (MODIS) radiances at 3.7, 6.7, 11.0, and 12.0 µm against CloudSat‐estimated τ during the nighttime using 2 months of matched global data from 2007. An independent data set comprising observations from the same 2 months of 2008 was used to validate the ICODIN. One 4‐channel and three 3‐channel versions of the ICODIN were tested. The training and validation results show that IR channels can be used to estimate ice cloud τ up to 150 with correlations above 78% and 69% for all clouds and only opaque ice clouds, respectively. However, τ for the deepest clouds is still underestimated in many instances. The corresponding RMS differences relative to CloudSat are ~100 and ~72%. If the opaque clouds are properly identified with the IR methods, the RMS differences in the retrieved optical depths are ~62%. The 3.7 µm channel appears to be most sensitive to optical depth changes but is constrained by poor precision at low temperatures. A method for estimating total optical depth is explored for estimation of cloud water path in the future. Factors affecting the uncertainties and potential improvements are discussed. With improved techniques for discriminating between opaque and semitransparent ice clouds, the method can ultimately improve cloud property monitoring over the entire diurnal cycle.
Hyporheic exchange controlled by dynamic hydrologic boundary conditions
Authors: Schmadel Noah M. , Ward Adam S. , Lowry Christopher S. , Malzone Jonathan M.
Published: April 2016

The relative roles of dynamic hydrologic forcing and geomorphology as controls on the timescales and magnitudes of stream‐aquifer exchange and hyporheic flow paths are unknown but required for management of stream corridors. We developed a comprehensive framework relating diel hydrologic fluctuations to hyporheic exchange in the absence of geomorphic complexity. We simulated groundwater flow through an aquifer bounded by a straight stream and hillslope and under time‐varying boundary conditions. We found that diel fluctuations can produce hyporheic flow path lengths and residence times that span orders of magnitude. With these results, hyporheic flow path residence times and lengths can be predicted from the timing and magnitude of diel fluctuations and valley slope. Finally, we demonstrated that dynamic hydrologic boundary conditions can produce spatial and temporal scales of hyporheic flow paths equivalent to those driven by many well‐studied geomorphic features, indicating that these controls must be considered together in future efforts of upscaling to stream networks.
1,2,3,4‐Tetrahydronaphthalene (vapour) [Air Monitoring Methods, 2014]
Authors: Tschickardt M. , Bremer S. , Hebisch R. , Hartwig A. ,   MAK Commission
Published: April 2016

This analytical method is a validated measurement procedure for the determination of gaseous 1,2,3,4‐tetrahydronaphthalene and for monitoring its MAK value at workplaces. Sampling is performed by drawing a defined volume of air through an adsorption tube filled with Chromosorb 106. The flow rate can be set in the range from 5 to 60 mL/min with a recommended air sample volume of 1.2 L whereas the sampling time must be adjusted to the corresponding flow rate. The collected 1,2,3,4‐tetrahydronaphthalene is thermally desorbed and then analysed by means of gas chromatography fitted with two detectors, a flame ionisation detector (FID) for quantification and a mass selective detector (MSD) for identification and quantification. The quantitative determination is based on a calibration function obtained by means of a multiple‐point calibration using 1,2,3,4‐tetrahydronaphthalene as external standard. The limit of quantification (LOQ) is determined on the basis of aliquots from 1 to 10 mL of the calibration gas in the lower concentration range. The relative LOQ is 0.1 mg/m
3
with a mean recovery of 99%. The expanded uncertainty for this procedure is between 16 and 17%.
N‐Alkyl‐2‐pyrrolidones (N‐methyl‐2‐pyrrolidone, N‐ethyl‐2‐pyrrolidone), vapour [Air Monitoring Methods, 2014a]
Authors: Breuer D. , Ehmann E. , Rosenberger W. , Hebisch R. , Hartwig A. ,   MAK Commission
Published: April 2016

This analytical method is a validated measurement procedure for the determination of gaseous
N
‐methyl‐2‐pyrrolidone (NMP) and N‐ethyl‐2‐pyrrolidone (NEP) and for monitoring their Occupational Exposure Limits (OELs) or MAK values at workplaces. Both personal and stationary sampling can be performed for assessment of workplaces. Sampling is performed by drawing air through an ADS‐type silica gel tube using a suitable flow‐regulated pump with a volumetric flow rate of 20 L/h. Gaseous NMP and/or NEP are adsorbed onto the silica gel. For sample preparation the collected NMP and/or NEP are desorbed from the silica gel with a potassium hydroxide solution in methanol. The sample solutions are analysed by gas chromatography using a nitrogen‐selective detector (NPD) with dibutylamine as internal standard. The quantitative determination is based on calibration functions obtained by means of multiple‐point calibrations. The limit of quantification (LOQ) for both, NMP and NEP is 1.6 µg/mL (absolute 1.6 ng), which corresponds to a relative LOQ of 0.1 mg/m
3
based on an air sample volume of 40 L.
Addendum to 4,4'‐Methylene diphenyl diisocyanate (inhalable fraction)[BAT Value Documentation, 2007]
Authors: Leng G. , Reuter U. , Drexler H. , Hartwig A. ,   MAK Commission
Published: April 2016

4,4'‐Methylene diphenyl diisocyanate(MDI) (inhalable fraction) (14. Lieferung 2007)

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated 4,4'‐Methylene diphenyl diisocyanate (MDI) (inhalable fraction) in 2006. The Commission established a “Biologischer Leitwert” (BLW), which allows for a threshold value in spite of insufficient data in order to make use of the advantage of biological monitoring. The provisional BAT value to date was based on the relationship between external and internal exposure and was creatinine‐related. For an MDI concentration of 50 µg/m3, a urinary excretion of MDA of no more than 10 μg/g creatinine was obtained (Lewalter and Steinmann‐Steiner‐Haldenstätt 1994). The correlation is based on excretion data that are volume‐related, not creatinine‐related. Taking recent data from MDI monitoring, also from occupational medical sources, into account, a BLW (“Biologischer Leitwert”) of 10 μg 4,4'‐diaminodiphenylmethane (MDA) (after hydrolysis)/l urine is established. Sampling should be carried out at the end of exposure or the end of the shift.
Methoxyessigsäure [MAK Value Documentation in German language, 2016]
Authors: Hartwig A. ,   MAK Commission
Published: April 2016

Methoxyacetic acid

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of 1 ml/m
3
for methoxyacetic acid, considering the endpoints local and systemic toxicity as well as developmental toxicity. Methoxyacetic acid acts locally as well as systemically. It is the metabolite responsible for the haematotoxicity and reproductive toxicity of the better investigated methoxyethanol. Hence, the MAK value of 1 ml methoxyethanol/m
3
was also assigned to methoxyacetic acid in 2008. A 28‐day study with rats shows a NOAEC for systemic and local effects of 15 ml/m
3
. Since 2014, the Commission uses an empirical approach to set MAK values for substances with critical effects on the upper respiratory tract or the eyes. According to this approach, a concentration of 0.9 ml/m
3
for the workplace air can be calculated from this study. Therefore, the MAK value of 1 ml/m
3
is confirmed. Systemic as well as local effects are critical and the assignment to Peak Limitation Category II for systemic effects is retained. However, to avoid sensory irritation, the former excursion factor of 8 seems too high and is reduced to 2 in analogy to the excursion factors for formic and acetic acid. The assignment to Pregnancy Risk Group B, substances for which damage to the embryo or foetus cannot be excluded even when the MAK value is observed, is confirmed.
Trypsin und Chymotrypsin [MAK Value Documentation in German language, 2016]
Authors: van Kampen V. , Hartwig A. ,   MAK Commission
Published: April 2016

Trypsin (EC 3.4.21.4) and Chymotrypsin (EC 3.4.21.1)

Trypsin (EC 3.4.21.4) and Chymotrypsin (EC 3.4.21.1) are proteolytic pancreatic enzymes which are secreted as inactive precursors trypsinogen and chymotrypsinogen, respectively. They have several clinical pharmacological as well as laboratory applications and they are used in protein chemistry, especially in the preparation of insulin. Exposure to enzyme dusts has long been known to cause occupational immediate hypersensitivities of the airways. Also trypsin and chymotrypsin are potential inhalable sensitizers; cases of specific airway sensitization caused by trypsin and chymotrypsin containing products could be shown clearly by several studies. Positive skin prick and challenge tests as well as specific IgE antibodies have been described. Since these results and the clinical symptoms usually matched well, an immunological mechanism of action is suggested. There is no clear evidence of allergic cell‐mediated late type eczematous skin reactions. Trypsin and chymotrypsin are designated with “Sa” (for substances causing airway sensitization) but not with “Sh” (for skin‐sensitizing substances).
Polyvinylchlorid (PVC),[MAK Value Documentation in German language, 2016]
Authors: Hartwig A. ,   MAK Commission
Published: April 2016

Polyvinylchloride (PVC)

The German Commission for the Investigation of Health Hazards of Chemicals in the Work Area has re‐evaluated polyvinylchloride since a new maximum concentration at the workplace (MAK value) for poorly soluble dusts was established in 2011.

Polyvinylchloride (PVC) is a biopersistent granular dust. It is therefore classified in Carcinogen Category 4 and a MAK value of 0.3 mg/m3× material density for the respirable dust is established in analogy to biopersistent granular dusts. This value is valid for PVC containing no additives and having a monomer content of < 1%. The classification is based on animal data that showed increased tumour incidences in rats exposed to biopersistent granular dusts in the high dose range. These tumours are regarded to be a consequence of the inflammatory mechanism of action, for which thresholds can be defined. Direct genotoxic effects appear to be of subordinate relevance for the carcinogenicity of biopersistent granular dusts. In analogy to biopersistent granular dusts, Peak Limitation Category II with an excursion factor of 8 was established for PVC. Since PVC is not distributed systemically and accumulates only locally in the lungs, no developmental effects due to this dust are expected to occur at the MAK value of 0.3 mg/m3× material density. The assignment to Pregnancy Risk Group C is confirmed.
ortho‐Phenylphenol (OPP) und ortho‐Phenylphenol‐Natrium (OPP‐Na) [MAK Value Documentation in German language, 2016]
Authors: Hartwig A. ,   MAK Commission
Published: April 2016

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of o‐phenylphenol (OPP) and sodium o‐phenylphenol (OPP‐Na), considering all endpoints.

Bladder tumours were observed in rats after supplementation of food with OPP and OPP‐Na. The cause of these is regarded to be a cytotoxic effect in combination with species or gender‐specific factors and the effect is seen especially at high dosages at a saturation range in metabolism. A specific genotoxic effect could not be detected. OPP and OPP‐Na are therefore classified into Carcinogen Category 4; this means if the MAK value is observed, no carcinogenic effects are to be expected. The liver tumours which were observed in male mice are not taken into consideration for this evaluation due to their debatable relevance for humans.

After long‐term administration of 40 mg OPP/kg body weight and day via food supplements, rats showed no adverse effects. This NOAEL is equal to an air concentration of 98 mg/m3. In establishing the MAK value one must take into consideration the systemic effects and additionally the irritant effects of OPP or the corrosive effects of OPP‐Na. There are no data relevant to an evaluation of the local effects on the upper respiratory tract after repeated exposure either for humans or animals. Therefore a comparative structure analysis has been made for OPP to bisphenol A and a MAK value of 5 mg/m3I established. For OPP‐Na, a structure analogy to calcium hydroxide was considered, based on its alkali strength, and a MAK value of 2 mg/m3I was set.

Due to irritative effects, Peak Limitation Category I is established for both OPP and OPP‐Na. OPP was assigned an excursion factor of 1 based on the comparative analysis to bisphenol A. For OPP‐Na with its higher water solubility, a comparative analysis based on its alkali strength was made to calcium hydroxide and an excursion factor of 1 was also set.

As the NOAEL for developmentally toxic effects at workplace air concentrations is higher than the MAK value for OPP and OPP‐Na by a factor of 105 and 146, respectively, both substances are classified in Pregnancy Risk Group C.

Skin contact with either OPP or OPP‐Na is not expected to contribute significantly to systemic toxicity.
Fracture Behavior of Cracked Giant Magnetostrictive Materials in Three‐Point Bending under Magnetic Fields: Strain Energy Density Criterion
Authors: Colussi Marco , Berto Filippo , Mori Kotaro , Narita Fumio
Published: April 2016

In this paper, the fracture behavior of cracked giant magnetostrictive materials has been investigated both numerically and experimentally. Works in literature have been revisited, focusing on iron and rare‐earth alloys, such as Terfenol‐D. Three‐point bending tests have been carried out on precracked specimens and the fracture loads have been measured in the presence and absence of a magnetic field. Recent studies on local stress fields in proximity of crack tips have shown that the Strain Energy Density (SED) can be a robust parameter in the brittle fracture assessment. Coupled‐field finite element analyses have then been performed and the effect of the magnetic field on Terfenol‐D fracture resistance has been discussed in terms of Energy Release Rate and averaged SED.