bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of flying ashes according to the recent Pittsburgh symposium
Authors: López Ruiz A.
Published: November 2014

Not available
Criteria on cement specifications
Authors: Calleja J.
Published: November 2014

Not available
Qualitative determination of the constituents of hydraulic cements by X ray fluorescence
Authors: Sagrera J. L.
Published: November 2014

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Heat treatments of concrete
Authors: Calleja J.
Published: November 2014

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Development and tests with rubber protection in ball, tube, stone or rod mills
Authors: Mohr Kassel F.
Published: November 2014

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Concrete thermal treatments. 2nd part
Authors: Calleja J.
Published: November 2014

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How to determine the correct load of the grinding elements to secure optimum output
Authors: Jenness R. C.
Published: November 2014

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Automatic analysis by X ray spectrometry and associated computer in the cement industry
Authors: Von Euw M.
Published: November 2014

No available
Construction and exploitation possibilities of the automatic apparatus for the determination of carbonates, Holderbank system
Authors: Haegele W.
Published: November 2014

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Contribution to the microscopic study of the Portland cement structure. I
Authors: Calleja J. , Fernández París J. M.
Published: November 2014

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Concrete proportioning
Authors: Herreno Núñez E.
Published: November 2014

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Adhesives
Authors: Kennedy J. G.
Published: November 2014

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New research on the necessary steps to avoid harmful inclusions in lime
Authors: Schmidt E.
Published: November 2014

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International seminary on the automation of the lime, cement and similar industries
Authors: Editorial Equipo
Published: November 2014

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Method of automatic computer control of a cement plant
Authors: Hayes J. , Rais F.
Published: November 2014

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Use of computer systems for the automation of cement plants, especially in preparing the mixture of raws
Authors: Schrodt K.
Published: November 2014

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Prehomogeneization influence on the proportioning control of raws in cement by means of RFA (X ray fluorescence analysis) and digital computation
Authors: Buzzi Sandro
Published: November 2014

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Investigation on the meteorization of cements by infra-red spectroscopy
Authors: García de Paredes P. , Calleja J. , Vázquez T. , Cebrián J. L.
Published: November 2014

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Investigation on the strength of construction concrete
Authors: Wesche K.
Published: November 2014

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Identification and elimination of moulding defects in the brick industry
Authors: Schlinkert C.
Published: November 2014

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An empirical approximate method to calculate kiln capacity
Authors: Gieskieng D. H.
Published: November 2014

No available
A study of the causes of volume changes in cement paste
Authors: Chujo K. , Kondo M.
Published: November 2014

Not available
On the methods to study the durability of hydraulic cements
Authors: Calleja J. , García de Paredes P.
Published: November 2014

Not available
On the use of grinding additives in cement grinding
Authors: Schneider H.
Published: November 2014

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Examination of the uniformity of raws and accuracy of the multichannel X ray spectroscope
Authors: Eriangen J. Ess.
Published: November 2014

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Additions to concrete based on organic greases
Authors: Doty D. M.
Published: November 2014

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Automation problems in drying and grinding installations
Authors: Stürmer W.
Published: November 2014

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Coloration of brick surfaces
Authors: Anónimo .
Published: November 2014

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New proportioning method for set mortars and concretes, applying digital computers. (Comparison of the method with the «Full method for the chemical analysis of hardened concrete» of Cembureau)
Authors: Ruiz de Gauna A.
Published: November 2014

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Portland cement concretes with normal aggregate. Relation between maximum size of the granular skeleton and the mix water, for various consistencies and water-cement ratios
Authors: Sabesinsky Felperin M.
Published: November 2014

Not available
Specialised literature on the manufacture and use of expanded clay granules
Authors: Schmidt H.
Published: November 2014

Not available
VDZ International Congress (Association of Cement Manufacturers of Western Germany)
Authors: Editorial Equipo
Published: November 2014

Not available
Influence of time and mode of hydratation in the Le Chatelier-Anstell test
Authors: Sagrera J. L.
Published: November 2014

Not available
New proportioning analysis procedure in set mortars and concretes, using digital computers. (Comparison of this method with the «Complete method for the analysis of hardened concrete of Cembureau.) (Continued)
Authors: Ruiz de Gauna A.
Published: November 2014

Not available
Good practice cods for sulphate resisting concrete (remarks on requirements applicable to usable Portland cements)
Authors: Calleja J.
Published: November 2014

Not available
An investigation into the effectiveness of public entities’ procurement practices
Authors: Mofokeng Moitswadi , Luke Rose
Published: November 2014

The delivery of services through the procurement of goods and services requires proper strategic leadership and management processes. Inappropriate planning, under-spending of budgets and ineffective procurement form part of the root causes of poor service delivery, as this restricts the movement of resources to the right places. This study identified the leading procurement practices as: procurement strategy and leadership, the procurement process, human resource management, procurement information systems, supplier management and procurement performance management. These practices were then tested in public entities, mainly in Gauteng Province, South Africa, to determine the extent to which they are applied. The study found that there is a major divide between the perception of the level of application of the leading practices and actual implementation. Processes, skills, performance management, information technology (IT) systems and supplier management are applied inadequately or inappropriately. Most entities thus show a poor understanding of customer needs and there seems to be a general lack of customer focus. The study highlighted the best practice areas in which public entities are able to focus their efforts to better achieve excellent customer service and thus service delivery.
Torsion of Gravid Uterus due to Uterine Asymmetry associated with Placental Abruption, Intrauterine Fetal Demise, and Maternal Shock
Authors: Rathod Ashakiran Thavarsingh
Published: November 2014

A 24-year-old gravida 3 para 2 living 1 with 28 weeks gestation presented with acute abdomen and shock. A diagnosis of concealed abruption with intrauterine death of fetus was made and case was taken for emergency cesarean section. It turned out to be 180° levorotation of gravid uterus with abruption. Detorsion of the uterus failed. A dead fetus was delivered through a vertical incision on posterior wall of uterus. Asymmetrically, enlarged uterus and excess liquor were the associated findings. Total hysterectomy was done for uncontrolled atonic postpartum hemorrhage. Postoperative period was uneventful. Although a rare obstetric condition, torsion of gravid uterus should be considered in the differential diagnosis of placental abruption particularly when concealed.

How to cite this article

Rathod AT. Torsion of Gravid Uterus due to Uterine Asymmetry associated with Placental Abruption, Intrauterine Fetal Demise and Maternal Shock. Int J Infertil Fetal Med 2014;5(2):64-65.
Constraining black carbon aerosol over Southeast Asia using OMI aerosol absorption optical depth and the adjoint of GEOS-Chem
Authors: Zhang L. , Henze D. K. , Grell G. A. , Carmichael G. R. , Bousserez N. , Zhang Q. , Cao J.
Published: November 2014

Abstract. Accurate estimates of the emissions and distribution of Southeast Asian (70–150° E, 11° S–55° N) black carbon (BC) are critical to studies of the atmospheric environment and climate change. Analysis of modeled BC concentrations compared to in situ observations indicates levels are underestimated over most of Southeast Asia when using any of four different emission inventories. We thus attempt to reduce uncertainties in BC emissions and improve BC model simulations by developing top-down, spatially resolved, estimates of BC emissions through assimilation of OMI observations of aerosol absorption optical depth (AAOD) with the GEOS-Chem model and its adjoint for April and October of 2006. Overwhelming enhancements, up to 500%, in anthropogenic BC emissions are shown after optimization over broad areas of Southeast Asia in April. In October, the optimization of anthropogenic emissions yields a slight reduction (1 ~ 5%) over India and parts of southern China, while emissions increase by 10 ~ 50% over eastern China. Observational data from in situ measurements and AERONET observations are used to evaluate the BC inversions and assess the bias between OMI and AERONET AAOD. Low biases in BC concentrations are improved or corrected in most eastern and central sites over China after optimization, while the constrained model still underestimates concentrations in Indian sites in both April and October, possibly as a consequence of low prior emissions. Model resolution errors may contribute up to a factor of 2.5 to the underestimate of surface BC concentrations over northern India. We also compare the optimized results using different anthropogenic emission inventories and discuss the sensitivity of top-down constraints on anthropogenic emissions with respect to biomass burning emissions. In addition, the impacts of different observation operators and a priori constraints on the optimization are investigated. Overall, despite these limitations and uncertainties, using OMI AAOD to constrain BC sources improves model representation of BC distributions, particularly over China.
Stably stratified canopy flow in complex terrain
Authors: Xu X. , Yi C. , Kutter E.
Published: November 2014

Abstract. The characteristics of stably stratified canopy flows in complex terrain are investigated by employing the Renormalized Group (RNG) k-ε turbulence model. In this two-dimensional simulation, we imposed persistent constant heat flux at ground surface and linearly increasing cooling rate in the upper canopy layer, vertically varying dissipative force from canopy drag elements, buoyancy forcing induced from thermal stratification and the hill terrain. These strong boundary effects keep nonlinearity in the two-dimensional Navier–Stokes equations high enough to generate turbulent behavior. The fundamental characteristics of nighttime canopy flow over complex terrain measured by a few multi-tower advection experiments can be produced by this numerical simulation, such as: (1) unstable layer in the canopy, (2) super-stable layer associated with flow decoupling in deep canopy and near the top of canopy, (3) upward momentum transfer in canopy, and (4) large buoyancy suppression and weak shear production in strong stability.
A compact PTR-ToF-MS instrument for airborne measurements of volatile organic compounds at high spatiotemporal resolution
Authors: Müller M. , Mikoviny T. , Feil S. , Haidacher S. , Hanel G. , Hartungen E. , Jordan A. , Märk L. , Mutschlechner P. , Schottkowsky R. , Sulzer P. , Crawford J. H. , Wisthaler A.
Published: November 2014

Abstract. Herein, we report on the development of a compact proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) for airborne measurements of volatile organic compounds (VOCs). The new instrument resolves isobaric ions with a mass resolving power (m/Δm) of ~1000, provides accurate m/z measurements (Δm < 3 mDa), records full mass spectra at 1 Hz and thus overcomes some of the major analytical deficiencies of quadrupole-MS-based airborne instruments. 1 Hz detection limits for biogenic VOCs (isoprene, α total monoterpenes), aromatic VOCs (benzene, toluene, xylenes) and ketones (acetone, methyl ethyl ketone) range from 0.05 to 0.12 ppbV, making the instrument well-suited for fast measurements of abundant VOCs in the continental boundary layer. The instrument detects and quantifies VOCs in locally confined plumes (< 1 km), which improves our capability of characterizing emission sources and atmospheric processing within plumes. A deployment during the NASA 2013 DISCOVER-AQ mission generated high vertical- and horizontal-resolution in situ data of VOCs and ammonia for the validation of satellite retrievals and chemistry transport models.
Short-term effects of biogas digestate and cattle slurry application on greenhouse gas emissions affected by N availability from grasslands on drained fen peatlands and associated organic soils
Authors: Eickenscheidt T. , Freibauer A. , Heinichen J. , Augustin J. , Drösler M.
Published: November 2014

Abstract. A change in German energy policy has resulted in a strong increase in the number of biogas plants in Germany. As a consequence, huge amounts of nutrient-rich residues, the by-products of the fermentative process, are used as organic fertilizers. Drained peatlands are increasingly used to satisfy the huge demand for fermentative substrates (e.g., energy crops, grass silage) and the digestate is returned to the peatlands. However, drained organic soils are considered as hot spots for nitrous oxide (N2O) emissions and organic fertilization is additionally known to increase N2O emissions from managed grasslands. Our study addressed the questions (a) to what extent biogas digestate and cattle slurry application increase N2O and methane (CH4) fluxes as well as the mineral nitrogen use efficiency (NUEmin) and grass yield, and (b) how different soil organic matter contents (SOMs) and nitrogen contents promote the production of N2O. In addition NH3 volatilization was determined at one application event to obtain first clues with respect to the effects of soil and fertilizer types. The study was conducted at two sites within a grassland parcel, which differed in their soil organic carbon (SOC) and N contents. At each site (named Corg-medium and Corg-high) three plots were established: one was fertilized five times with biogas digestate, one with cattle slurry, and the third served as control plot. On each plot, fluxes of N2O and CH4 were measured on three replicates over 2 years using the closed chamber method. For NH3 measurements we used the calibrated dynamic chamber method. On an annual basis, the application of biogas digestate significantly enhanced the N2O fluxes compared to the application of cattle slurry and additionally increased the plant N-uptake and NUEmin. Furthermore, N2O fluxes from the Corg-high treatments significantly exceeded N2O fluxes from the Corg-medium treatments. Annual cumulative emissions ranged from 0.91 ± 0.49 to 3.14 ± 0.91 kg N ha−1 yr−1. Significantly different CH4 fluxes between the investigated treatments or the different soil types were not observed. Cumulative annual CH4 exchange rates varied between −0.21 ± 0.19 and −1.06 ± 0.46 kg C ha−1 yr−1. Significantly higher NH3 losses, NUEmin and grass yields from treatments fertilized with biogas digestate compared to those fertilized with cattle slurry were observed. The total NH3 losses following the splash plate application were 18.17 kg N ha−1 for the digestate treatments and 3.48 kg N ha−1 for the slurry treatments (36 and 15% of applied NH4+–N). The observed linear increase of 16 days' cumulative N2O–N exchange or annual N2O emissions, with mean groundwater level and ammonium application rate, reveals the importance of site-adapted N fertilization and the avoidance of N surpluses in Corg-rich grasslands.
Aggregates reduce transport distance of soil organic carbon: are our balances correct?
Authors: Hu Y. , Kuhn N. J.
Published: November 2014

Abstract. The effect of soil erosion on global carbon cycling, especially as a source or sink for greenhouse gases, has been the subject of intense debate. The controversy arises mostly from the lack of information on the fate of eroded soil organic carbon (SOC) whilst in-transit from the site of erosion to the site of longer-term deposition. Solving this controversy requires an improved understanding of the transport distance of eroded SOC, which is principally related to the settling velocity of sediment fractions that carry the eroded SOC. Although settling velocity has already been included in some erosion models, it is often based on mineral particle size distribution. For aggregated soils, settling velocities are affected by their actual aggregate size rather than by mineral particle size distribution. Aggregate stability is, in turn, strongly influenced by SOC. In order to identify the effect of aggregation of source soil on the transport distance of eroded SOC, and its susceptibility to mineralization after transport and temporary deposition, a rainfall simulation was carried out on a silty loam. Both the eroded sediments and undisturbed soils were fractionated into six different size classes using a settling tube apparatus according to their settling velocities: > 250, 125 to 250, 63 to 125, 32 to 63, 20 to 32 and < 20 μm. Weight, SOC content and instantaneous respiration rates were measured for each of the six class fractions. Our results indicate that (1) 41% of the eroded SOC was transported with coarse aggregates that would be likely re-deposited down eroding hillslopes, rather than with fine particles likely transferred to water courses; (2) erosion was prone to accelerate the mineralization of eroded SOC, and thus might contribute more CO2 to the atmosphere than current estimates which often ignore potential effects of aggregation; (3) preferential deposition of SOC-rich coarse aggregates potentially causes an increase of SOC remaining in the colluvial system and a reduction of SOC flux to the alluvial or aquatic system. These findings identify a potential error of overestimating net erosion-induced carbon sink effects, and thus add an additional factor to consider when improving our current understanding of SOC erosion and deposition on hillslopes.
Alkali element background reduction in laser ICP-MS
Authors: Magee C. W. , Norris C. A.
Published: November 2014

Abstract. Alkali backgrounds in laser ablation ICP-MS analyses can be enhanced by electron-induced ionization of alkali contamination on the skimmer cone, reducing effective detection limits for these elements. Traditionally, this problem is addressed by isolating analyses of high alkali materials onto a designated cone set, or by operating the ICP-MS in a "soft extraction" mode, which reduces the energy of electrons repelled into the potentially contaminated sampling cone by the extraction field. Here we present a novel approach, where we replace the traditional alkali glass tuning standards with synthetic low-alkali glass reference materials. Using this vitreous tuning solution, we find that this approach reduces the amount of alkali contamination produced, halving backgrounds for the heavy alkali elements without any change to analytical procedures. Using segregated cones is still the most effective method for reducing lithium backgrounds, but since the procedures are complimentary both can easily be applied to the routine operations of an analytical lab.
gpuPOM: a GPU-based Princeton Ocean Model
Authors: Xu S. , Huang X. , Zhang Y. , Fu H. , Oey L.-Y. , Xu F. , Yang G.
Published: November 2014

Abstract. Rapid advances in the performance of the graphics processing unit (GPU) have made the GPU a compelling solution for a series of scientific applications. However, most existing GPU acceleration works for climate models are doing partial code porting for certain hot spots, and can only achieve limited speedup for the entire model. In this work, we take the mpiPOM (a parallel version of the Princeton Ocean Model) as our starting point, design and implement a GPU-based Princeton Ocean Model. By carefully considering the architectural features of the state-of-the-art GPU devices, we rewrite the full mpiPOM model from the original Fortran version into a new Compute Unified Device Architecture C (CUDA-C) version. We take several accelerating methods to further improve the performance of gpuPOM, including optimizing memory access in a single GPU, overlapping communication and boundary operations among multiple GPUs, and overlapping input/output (I/O) between the hybrid Central Processing Unit (CPU) and the GPU. Our experimental results indicate that the performance of the gpuPOM on a workstation containing 4 GPUs is comparable to a powerful cluster with 408 CPU cores and it reduces the energy consumption by 6.8 times.
Spatial analysis of precipitation in a high-mountain region: exploring methods with multi-scale topographic predictors and circulation types
Authors: Masson D. , Frei C.
Published: November 2014

Abstract. Statistical models of the relationship between precipitation and topography are key elements for the spatial interpolation of rain-gauge measurements in high-mountain regions. This study investigates several extensions of the classical precipitation–height model in a direct comparison and within two popular interpolation frameworks, namely linear regression and kriging with external drift. The models studied include predictors of topographic height and slope at several spatial scales, a stratification by types of a circulation classification, and a predictor for wind-aligned topographic gradients. The benefit of the modeling components is investigated for the interpolation of seasonal mean and daily precipitation using leave-one-out cross-validation. The study domain is a north–south cross section of the European Alps (154 km × 187 km) that is inclined towards dense rain-gauge measurements (approx. 440 stations, 1971–2008). The significance of the topographic predictors was found to strongly depend on the interpolation framework. In linear regression, predictors of slope and at multiple scales reduce interpolation errors substantially. But with as many as nine predictors, the resulting interpolation still poorly replicates the across-ridge variation of climatological mean precipitation. Kriging with external drift (KED) leads to much smaller interpolation errors than linear regression, but this is achieved with a single predictor (local topographic height), whereas the incorporation of more extended predictor sets brings only marginal further improvement. Furthermore, the stratification by circulation types and the wind-aligned gradient predictor do not improve over the single predictor KED model. As for daily precipitation, interpolation accuracy improves considerably with KED and the use of a single predictor field (the distribution of seasonal mean precipitation) as compared to ordinary kriging (i.e., without any predictor). Nonetheless, information from circulation types did not improve interpolation accuracy. Our results confirm that the consideration of topography effects is important for spatial interpolation of precipitation in high-mountain regions. But a single predictor may be sufficient and taking appropriate account of the spatial autocorrelation (by kriging) can be more effective than the development of elaborate predictor sets within a regression model. Our results also question a popular practice of using linear regression for predictor selection in spatial interpolation; however they support the common practice of using a climatological mean field as a background in the interpolation of daily precipitation.
Fully probabilistic seismic source inversion – Part 1: Efficient parameterisation
Authors: Stähler S. C. , Sigloch K.
Published: November 2014

Abstract. Seismic source inversion is a non-linear problem in seismology where not just the earthquake parameters themselves but also estimates of their uncertainties are of great practical importance. Probabilistic source inversion (Bayesian inference) is very adapted to this challenge, provided that the parameter space can be chosen small enough to make Bayesian sampling computationally feasible. We propose a framework for PRobabilistic Inference of Seismic source Mechanisms (PRISM) that parameterises and samples earthquake depth, moment tensor, and source time function efficiently by using information from previous non-Bayesian inversions. The source time function is expressed as a weighted sum of a small number of empirical orthogonal functions, which were derived from a catalogue of >1000 source time functions (STFs) by a principal component analysis. We use a likelihood model based on the cross-correlation misfit between observed and predicted waveforms. The resulting ensemble of solutions provides full uncertainty and covariance information for the source parameters, and permits propagating these source uncertainties into travel time estimates used for seismic tomography. The computational effort is such that routine, global estimation of earthquake mechanisms and source time functions from teleseismic broadband waveforms is feasible.
Hydrostatic grounding line parameterization in ice sheet models
Authors: Seroussi H. , Morlighem M. , Larour E. , Rignot E. , Khazendar A.
Published: November 2014

Abstract. Modeling of grounding line migration is essential to accurately simulate the behavior of marine ice sheets and investigate their stability. Here, we assess the sensitivity of numerical models to the parameterization of the grounding line position. We run the MISMIP3D benchmark experiments using the Ice Sheet System Model (ISSM) and a two-dimensional shelfy-stream approximation (SSA) model with different mesh resolutions and different sub-element parameterizations of grounding line position. Results show that different grounding line parameterizations lead to different steady state grounding line positions as well as different retreat/advance rates. Our simulations explain why some vertically depth-averaged model simulations deviate significantly from the vast majority of simulations based on SSA in the MISMIP3D benchmark. The results reveal that differences between simulations performed with and without sub-element parameterization are as large as those performed with different approximations of the stress balance equations in this configuration. They also demonstrate that the reversibility test is passed at relatively coarse resolution while much finer resolutions are needed to accurately capture the steady-state grounding line position. We conclude that fixed grid SSA models that do not employ such a parameterization should be avoided, as they do not provide accurate estimates of grounding line dynamics, even at high spatial resolution. For models that include sub-element grounding line parameterization, in the MISMIP3D configuration, a mesh resolution finer than 2 km should be employed.
Randomized Trial of Frequent Low-Efficiency and Short Hemodialysis/Hemofiltration in Hemodialysis Patients with Acute Brain Injury
Authors: Okada Kazuyoshi , Abe Masanori , Takashima Hiroyuki , Baba Seishiro , Taniguchi Machiko , Suzuki Hiroko , Yoshida Yoshinori , Oikawa Osamu , Maruyama Noriaki , Soma Masayoshi
Published: November 2014

Purpose

The aim of the study was to compare effects of frequent low-efficiency and short hemodialysis (FLESHD) and frequent low-efficiency and short hemofiltration (FLESHF) in hemodialysis (HD) patients with acute brain injury (ABI).

Methods

We randomly divided 13 HD patients with ABI into FLESHD (n = 6) or FLESHF (n = 7) groups. Conditions for the first to third sessions were as follows. FLESHD: intravenous administration of glycerol 400 ml/session, blood flow rate (QB) 100 ml/min, dialysate flow rate 300 ml/min, and treatment duration 2 h (HD-1). FLESHF: intravenous administration of glycerol 400 ml/session, QB 150 ml/min, substitution flow rate 10 l/session, and treatment duration 4 h (HF-1). After the fourth session, we gradually changed the conditions and stopped glycerol administration (HD-2 and HF-2).

Results

There were no significant differences in survival rate, consciousness level, or adverse effects during hospitalization in either group. In mixed model analysis, the level of HCO3– post FLESHF was significantly (p≤0.0001) increased compared with the level post FLESHD. However, no significant differences were seen in the levels of osmolality, in blood pressure before and after either dialysis method, or in the level of HCO3– pre dialysis. The variation in the relative ratio of BUN before FLESHF was significantly higher (p≤0.05) than the relative ratio before FLESHD in the sixth session. In the FLESHD groups, serum sodium was higher and serum potassium was lower than in the FLESHF groups.

Conclusions

FLESHD with glycerol under these conditions may be a better therapeutic option for managing patients with ABI, although the short-term survival rate is similar.
Implementation of Recurrent Artificial Neural Networks for Nonlinear Dynamic Modeling in Biomedical Applications
Authors: Stošović Miona V. Andrejević , Litovski Vančo B.
Published: November 2014

Simulation is indispensable during the design of many biomedical prostheses that are based on fundamental electrical and electronic actions. However, simulation necessitates the use of adequate models. The main difficulties related to the modeling of such devices are their nonlinearity and dynamic behavior. Here we report the application of recurrent artificial neural networks for modeling of a nonlinear, two-terminal circuit equivalent to a specific implantable hearing device. The method is general in the sense that any nonlinear dynamic two-terminal device or circuit may be modeled in the same way. The model generated was successfully used for simulation and optimization of a driver (operational amplifier)-transducer ensemble. This confirms our claim that in addition to the proper design and optimization of the hearing actuator, optimization in the electronic domain, at the electronic driver circuit-to-actuator interface, should take place in order to achieve best performance of the complete hearing aid.
Design and validation of a diaphragm pump for pediatric CRRT during ECMO
Authors: Santhanakrishnan Arvind , Nestle Trent , Moore Brian L. , Yoganathan Ajit P. , Paden Matthew L.
Published: November 2014

Purpose

Children requiring artificial heart-lung support through extracorporeal membrane oxygenation (ECMO) are at increased risk of developing acute kidney injury (AKI). Continuous renal replacement therapy (CRRT) is the preferred method of treatment in pediatric AKI patients. CRRT devices are noted to provide inaccurate fluid balance (FB) when operated under low flow rates seen in children. We present the design and validation of a novel pump concept to provide accurate pediatric CRRT during ECMO.

Methods

A diaphragm pump was prototyped with a working stroke volume (SV) of 7 mL. Fluid transport occurs by periodic expansion and contraction of a flexible membrane due to pressure fluctuations of hydraulic fluid contained below its surface. Comparison of intravenous (IV) pumps to the diaphragm pump was conducted in vitro across the range of pressures observed during CRRT in ECMO. The pump was integrated into a CRRT circuit parallel with ECMO and FB accuracy was evaluated.

Results

The pump design improved efficiency of fluid transport, with flow rate errors as low as 1-5 ml/hr as compared to IV pumps (15-50 ml/hr). The SV of IV pumps increased with source pressure in a nearly linear manner compared to the minimal variation produced by the diaphragm pump. Inclusion of the diaphragm pump in a conventional CRRT circuit with ECMO improved the FB accuracy.

Conclusions

A novel diaphragm pump concept has been presented for providing CRRT during ECMO in the pediatric population. Improvement of the pump accuracy compared to currently used CRRT pumps was demonstrated via in vitro testing.
Development and Analysis of Semi-Interpenetrating Polymer Networks for Brain Injection in Neurodegenerative Disorders
Authors: Tunesi Marta , Batelli Sara , Rodilossi Serena , Russo Teresa , Grimaldi Annalisa , Forloni Gianluigi , Ambrosio Luigi , Cigada Alberto , Gloria Antonio , Albani Diego , Giordano Carmen
Published: November 2014

Purpose

Our aim was to assess the use of injectable, biocompatible and resorbable, hydrogel-based tools for innovative therapies against brain-related neurodegenerative disorders like Alzheimer's (AD) and Parkinson's (PD) diseases.

Methods

Two compositions of semi-interpenetrating polymer networks (semi-IPNs) based on collagen and poly(ethylene glycol) (PEG) were investigated. We examined their viscoelastic properties, flow behavior, functional injectability, as well as in vitro biocompatibility with SH-SY5Y human neuroblastoma cells and murine primary neurons. We also evaluated the in vivo biological performance after subcutaneous and brain injection in mice.

Results

The selected semi-IPNs showed a gel-like behavior and were injectable through a 30 G needle, with the maximum load ranging from 3.0 to 3.9 N. In vitro results showed that immortalized cells kept their proliferative potential and neurons maintained their viability after embedding in both materials, with better performances for the gel with the higher collagen content. For both semi-IPNs, after subcutaneous injection, the inflammatory response was negligible; after brain injection, the tissue did not show any signs of damage or degeneration.

Conclusions

The results suggest that the selected semi-IPNs not only represent a proper environment for cells, but also, once injected in vivo, do not induce damage/inflammation in the surrounding brain tissue. These findings represent a crucial starting point for the development of minimally invasive and injectable hydrogel-based tools for innovative drug/cell-based therapeutic strategies against AD, PD, or other severe brain-related neurodegenerative pathologies.
Sternal Closure following Negative Pressure Wound Therapy: A Safe Approach with a New Titanium Device
Authors: Santarpino Giuseppe , Pollari Francesco , Fischlein Theodor J.
Published: November 2014

Background

The application of negative pressure wound therapy (NPWT) in patients with deep wound infection after cardiac surgery has steadily increased worldwide. Following NPWT, in patients with concomitant sternal diastasis, preparation of the substernal structures for the sternal wires application is mandatory, with increased risk of severe complications, such as laceration of the right ventricle. The aim of this study is to present an innovative technique for sternal closure after NPWT, using the ASCS® System (ASCS atraumatic Sternum Closure System; KS Handelsvertretung Produktinovation, Bad Homburg, Germany).

Methods

Between January 2009 and August 2012, 88 patients (mean age 64.2 ± 12.4 years) with deep wound infection and sternal diastasis received NPWT; 16 of these patients (18.2%) underwent sternal closure after NPWT with ASCS®.

Results

In all 16 cases, neither sub-sternal dissection nor placement of trans- or peristernal wires was necessary. No damage to the aortocoronary bypass and ventricular rupture occurred. Minimal post-operative bleeding from Redon drains (mean 40 ± 10 ml) was present. At follow-up, deep wound infection and sternal diastasis did not occur.

Conclusions

The ASCS® System combined with NPWT in patients with postoperative deep wound infection and sternal diastasis is a feasible and safe procedure. Because preparation of the substernal structures is not necessary, this device might prevent the occurrence of severe complications. Our experience, however, is limited and larger case series are necessary to fully evaluate this new and innovative technique.
Numerical Washout Study of a Pulsatile Total Artificial Heart
Authors: Sonntag Simon J. , Kaufmann Tim A.S. , Büsen Martin R. , Laumen Marco , Gräf Felix , Linde Torsten , Steinseifer Ulrich
Published: November 2014

Purpose

For blood pumps with long term indication, blood stagnation can result in excessive thromboembolic risks for patients. This study numerically investigates the washout performance of the left pump chamber of a pulsatile total artificial heart (TAH) as well as the sensitivity of the rotational orientation of the inlet bileaflet mechanical heart valve (MHV) on blood stagnation.

Methods

To quantitatively evaluate the washout efficiency, a fluid-structure interaction (FSI) simulation of the artificial heart pumping process was combined with a blood washout model. Four geometries with different orientations (0°, 45°, 90° and 135°) of the inlet valve were compared with respect to washout performance.

Results

The calculated flow field showed a high level of agreement with particle image velocimetry (PIV) measurements. Almost complete washout was achievable after three ejection phases. Remains of old blood in relation to the chamber volume was below 0.6% for all configurations and were mainly detected opposite to the inlet and outlet port at the square edge where the membrane and the pump chamber are connected. Only a small variation in the washout efficiency and the general flow field was observed. An orientation of 0° showed minor advantages with respect to blood stagnation and recirculation.

Conclusions

Bileaflet MHVs were demonstrated to be only slightly sensitive to rotation regarding the washout performance of the TAH. The proposed numerical washout model proved to be an adequate tool to quantitatively compare different configurations and designs of the artificial organ regarding the potential for blood stagnation where experimental measurements are limited.
Effects of NiTi Rotary and Reciprocating Instruments on Debris and Smear Layer Scores: An SEM Evaluation
Authors: Poggio Claudio , Dagna Alberto , Chiesa Marco , Scribante Andrea , Beltrami Riccardo , Colombo Marco
Published: November 2014

Purpose

The purpose of the present study was to investigate the cleaning efficacy of 2 different nickel-titanium (NiTi) rotary systems: a new single system Reciproc compared with the rotary full sequence Mtwo. The amount of debris and the morphology of smear layer were the parameters for the evaluation of the cleanliness of root canals. The null hypothesis of the study was that there would be no significant difference in debris scores and smear layer scores between the 2 systems.

Methods

Forty single-rooted freshly extracted teeth were selected and divided into 2 groups. For each group, all root canals were shaped with 2 different NiTi instruments (Mtwo and Reciproc) and irrigated with 5.25% NaOCl and 17% ethylenediaminetetraacetic acid (EDTA) solutions by 3 trained operators. Specimens were fractured longitudinally and prepared for scanning electron microscopy (SEM) analysis at a standard magnification of ×5,000. The presence/absence of smear layer and the presence/absence of debris at the coronal, middle and apical third of each canal were evaluated using two 5-step scales for scores. Numeric data were analyzed using the Kruskal-Wallis and Mann-Whitney U statistical tests, and significance was set at a P value <0.05.

Results

This study revealed significant differences among the various groups. The Mtwo group presented significantly lower smear layer scores than the Reciproc group (P<0.01) in the middle and apical third of the canal.

Conclusions

Conventional continuous rotary NiTi instruments associated with 5.25% NaOCl and 17% EDTA solutions seem to be better for obtaining clean dentinal canal walls. Reciprocating instruments leave a higher quantity of smear layer which covers dentinal walls and dentinal tubules.
Characterisation and Comparison of the Host Response of 6 Tissue-Based Surgical Implants in a Subcutaneous in vivo Rat Model
Authors: Bryan Nicholas , Ashwin Helen , Smart Neil J. , Wohlert Stephen , Bayon Yves , Hunt John A.
Published: November 2014

Background

Hernia repair often involves fascial augmentation using biologic prostheses. Small processing changes during preparation modulate host tissue response, which influence material efficacy and longevity. In this pilot study, a rat model was used to determine the specific influence of tissue origin, decellularisation treatment and 1,6-hexamethylene diisocyanate (HMDI) cross-linking.

Methods

Materials (1 cm2) were implanted subcutaneously into 6-week-old Wistar rats (4 materials per animal, n=6/material per time point) for 2, 5, 7, 14 and 28 days. Histologic processing was carried out after resin infiltration, observing classical histopathology and pathologic indexing. Materials comprised 6 tissue-based grafts covering both experimental and commercial porcine decellularised dermal and small intestinal submucosal materials.

Results

Subcutaneous delivery of biologics demonstrated material-specific inflammatory/host responses. Controlled variations of the Permacol™ manufacturing process showed sodium dodecyl sulfate (SDS) was the most proinflammatory decellularisation reagent, and HMDI cross-linking had no effect on host response. All materials remained recoverable after 28 days, although Surgisis™ had partially resorbed.

Conclusion

Differences in host responses exist between biologic implants for hernia repair in this rat model. It is postulated that these modifications are induced during processing and may have an effect on the clinical outcome of hernia repair.
Effect of Surface Treatments on the Bond Strength of Veneering Ceramic to Zirconia
Authors: Korkmaz Fatih Mehmet , Bagis Bora , Turgut Sedanur , Ates Sabit Melih , Ayaz Elif Aydogan
Published: November 2014

Aim

The purpose of this study was to evaluate the effect of different surface treatments on the bond strength of veneering ceramic to zirconia.

Methods

Square (15 mm x 10 mm x 2 mm) zirconia specimens (n=18) received one of the following surface treatments: Group 1, sandblasting; Group 2, Clearfil ceramic primer application; Group 3, grinding; Group 4, alloy primer application; and Group 5, RelyX ceramic primer application. The zirconia core specimens were layered with a veneering porcelain (5 mm x 3 mm x 3 mm). Mean shear bond strength values (MPa) were calculated. Data were analyzed with one-way ANOVA and Tukey's post hoc pairwise comparisons (α=0.05). Fractured surfaces of the specimens were examined with scanning electron microscope (SEM).

Results

This study showed that bond strengths of the metal primer-treated zirconia specimens (Group 4) were significantly higher than those of the other paired groups. The application of metal primer affected the specimens' failure mode. SEM analysis demonstrated that Group 4 had mainly cohesive fractures, while the other groups showed approximately equal levels of adhesive and mixed fracture types. The mean and SD values for shear bond strengths ranged from 8.90 ± 3.42 MPa (Group 2) to 19.74 ± 4.96 MPa (Group 4).

Conclusions

In conclusion, the application of a metal primer to a zirconia core increased the bond strength of veneering ceramics. The use of chemical agents to improve the strength of the zirconia core's bond to veneering ceramic may have more benefits than the use of mechanical pretreatments.
MicroRNAs 143 and 145 May be Involved in Benign Prostatic Hyperplasia Pathogenesis through Regulation of Target Genes and Proteins
Authors: Viana Nayara I. , Reis Sabrina T. , Dip Nelson G. , Morais Denis R. , Moura Caio M. , Silva Iran A. , Katz Betina , Srougi Miguel , Leite Katia R. M. , Antunes Alberto A.
Published: November 2014

Objectives

The aim of this study was to analyze the roles of miR-143 and miR-145, as well as the gene and protein expression of their targets ( KRAS, ERK5, MAP3K3, and MAP4K4) in the pathogenesis of benign prostatic hyperplasia (BPH).

Methods

We analyzed the specimens of 44 patients diagnosed with BPH who underwent surgical treatment. The control group consisted of prostate samples from 2 young patients who were organ donors. miRNAs and their target genes were assessed using real-time polymerase chain reaction (qRT-PCR), and protein levels were assessed by Western blotting.

Results

miR-143 and miR-145 were overexpressed in, respectively, 62.5% and 73.8% of the cases. The ERK5 and MAP4K4 genes were underexpressed respectively in 59.4% and 100% of the BPH samples, whereas KRAS and MAP3K3 were overexpressed respectively in 79.4% and 61.5% of the samples. Increased protein expression was found for both KRAS (4,312.2 luminance/area) and MAP3K3 (7,461.7 luminance/area), while the ERK5 protein was more abundant in the samples from patients with prostate larger than 60 grams (p=0.019).

Conclusions

The overexpression of miR-143 and miR-145 in BPH samples suggests an association with the pathogenesis of the disease; additionally, the latter miRNA may act through the inhibition of MAP4K4. KRAS and MAP3K3 overexpression may also be associated with BPH pathogenesis. Further analyses are necessary to confirm these results.
Tumor Microvasculature Characteristics Studied by Image Analysis: Histologically-Driven Angiogenic Profile
Authors: Fakhrejahani Elham , Asao Yasufumi , Toi Masakazu
Published: November 2014

Angiogenesis, a hallmark of cancer, has been studied to be a potential marker for diagnosis, prognosis and therapy in breast cancer. To evaluate tumor angiogenesis, histological assessment has been a common approach and counting tumor microvessels after visualizing them by immunohistochemistry has been in use for a long time. With recent advances in digital pathology and image analysis, other characteristics of tumor vasculature can also be evaluated. In this article we briefly review the potentials of image analysis in assessing tumor microvessel morphologically that might be helpful in defining a better angiogenesis marker than other common markers like vessel count.
Which Accesses should be Abandoned or Revised?
Authors: Gibbons Christopher P.
Published: November 2014

This review considers the factors in deciding whether to abandon a functioning access. Strong indications for ligation or excision of an access are infection or severe early-onset steal. Access ligation may also be required for central vein occlusion or high-output cardiac failure. In general, a failing or thrombosed access should be restored to function unless it is no longer required. For failing or thrombosed distal arteriovenous fistulas, it may be easiest to abandon it and create a new fistula a few centimetres proximally rather than perform angioplasty, which is likely to require repeating. Other accesses may be abandoned after repeated treatment of the same stenosis over a short period provided other options exist.
Elbow Arteriovenous Fistulae
Authors: Wilmink Teun
Published: November 2014

Multiple superficial veins in different anatomical configurations exist in the elbow. The resulting variety of elbow arteriovenous fistulae (AVFs) is described in this paper. A classification of elbow AVF in nontransposed AVF, transposed AVF and multiple outflow AVF is proposed. The nontransposed brachiocephalic AVF has the lowest primary failure rate and a good medium-term survival particularly in the elderly. The simplest technique is an end-to-side anastomosis of the median cubital vein to the brachial artery. In cases of small upper arm veins, a perforating vein AVF, using multiple outflow tracts, may be helpful to lower primary failure risk. In the era of vein mapping with portable ultrasound elbow AVF should be made when forearm veins are exhausted or too small. A side-to-side AVF in order to enhance retrograde flow in the median forearm vein seems rarely indicated, in particular considering the greater risk of steal and venous hypertension. A transposed brachiobasilic AVF is a tertiary access procedure after the simpler alternatives have been exhausted. There is conflicting evidence of the benefits of one-stage versus two-stage procedures. Therefore, the type of operation should be tailored to the individual patient.