bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Insights into Mechanisms of Oil Recovery by Low Salinity Water Injection
Authors: Sohrabi M. , Mahzari P. , Farzaneh S. A. , Mills J. R. , Tsolis P. , Ireland S.
Published: March 2015

The underlying mechanism of oil recovery by low salinity water injection (LSWI) is still unknown. It would, therefore, be difficult to predict the performance of reservoirs under LSWI. A number of mechanisms have been proposed in the literature but these are controversial and have largely ignored crucial fluid/fluid interactions. Our direct flow visualization investigations have revealed that a physical phenomenon takes place when certain crude oils are contacted by low salinity water leading to a spontaneous formation of micelles which can be seen in the form of micro-dispersions in the oil phase.

In this paper, we present the results of a comprehensive study that includes experiments at different scales designed to systematically investigate the role of the observed crude oil/brine interaction and micelle formation in the process of oil recovery by LSWI. The experiments include; direct flow (micromodel) visualization, crude oil characterization, coreflooding, and spontaneous imbibition experiments. We establish a clear link between the formation of these micelles, the natural surface active components of crude oil, and the improvement in oil recovery due to LSWI. We present the results of a series of spontaneous and forced imbibition experiments carefully designed using reservoir cores to investigate the role of the micro-dispersions in wettability alteration and oil recovery. To further assess the significance of this mechanism, in a separate exercise, we eliminate the effect of clay by performing a LSWI experiment in a clay-free core. Absence of clay minerals is expected to significantly reduce the influence of the previously proposed mechanisms for oil recovery by LSWI. Nevertheless, we observe significant additional oil recovery compared to high salinity water injection in the clay-free porous medium. The additional oil recovery is attributed to the formation of micelles stemming from the crude oil/brine interaction mechanism described in this work and our previous related publications. Compositional analyses of the oil produced during this coreflood experiment indicates that the natural surface active compounds of the crude oil had been desorbed from the rock surfaces during the LSWI period of the experiment when the additional oil was produced.

The results of this study present new insights into the fundamental mechanisms involved in oil recovery by LSWI and new criteria for evaluating the potential of LSWI for application in oil reservoirs. The fluid/fluid interactions revealed in this research applies to oil recovery from both sandstone and carbonate oil reservoirs.
Detecting and Correcting Pipeline Leaks Before They Become a Big Problem
Authors: Cramer R. , Tulalian R. , Angelo P. , Van Stuijvenberg M. , Shaw D.
Published: March 2015

Timely pipeline leak detection is a significant business issue in view of a long history of catastrophic incidents and growing intolerance for such events. It is vital to flag containment loss and location quickly, credibly and reliably, for all green, brown field critical lines in order to shut down the line safely and isolate the leak. Pipelines are designed to transport hydrocarbons safely; however, leaks have severe safety, economic, environmental and reputational effects.

This paper will highlight robust, reliable and cost effective methods, most of which leverage real time instrumentation, telecommunications, SCADA, DCS, and associated online leak detection applications.

The purpose of this paper will be to review the underlying Leak Detection business issues, catalogue the functional challenges and describe experiences with available technologies. Internal and External techniques will be described, including basic rate of change of flow and pressure, compensated mass balance, statistical, real time transient modeling, acoustic wave sensing, fiber optic cable (distributed temperature, distributed acoustic sensing) and subsea hydrophones. The paper will also describe related credibility, deployment, organizational and maintenance issues with an emphasis on upstream applications.

The scope will include leak detection for pipelines conveying various flowing fluids – gas, liquid and multiphase flow. Pipeline environments will include subsea and onshore.

Advantages, disadvantages and experiences with these techniques will be described and analyzed.
Predicting Water Movement Using a Discrete Fracture Network Approach Combined with Fluid Flow Modeling in a Naturally Fractured Carbonate Reservoir
Authors: Jambayev A.S. , Todd Hoffman B.
Published: March 2015

Predicting the movement of fluids in large naturally-fractured carbonate reservoirs is challenging because of the many uncertainties such as complicated fracture networks and the heterogeneity of carbonate rock; however, flow models are necessary to understand and predict reservoir behavior. In this paper, we study one such reservoir where there are concerns with the potential for very high water production.

A well from this reservoir was suspended due to water cut (up to 60%) shortly after putting it on production, and there is concern that the water seen at the well might end up at nearby wells. The objective of dynamic analysis is to predict potential water flow from the aquifer through the fractures to two other producing wells.

A three well section of this reservoir is studied by combining a discrete fracture network (DFN) model with a finite difference flow simulator. Fracture parameters such as intensity, size, shape, and orientation are assigned to each fracture based on measured data or relevant statistical distribution derived from the measured data. Well test results, using the constructed DFN models and the results of actual test, are used to determine skin and fracture permeability. The DFN model is then upscaled to obtain grid properties including porosity, permeability and sigma factor suitable for a dual porosity flow simulation model.

Many different scenarios are simulated with different water influx rates and different DFN models, which show the wide range of water breakthrough times (16 to 161 months) and cumulative produced water volumes (8,000 to 1,000,000 bbl), however the largest impact on the results is the aquifer strength. We recommend further testing the shut-in well to try to estimate the influx potential, so a more accurate prediction can be made for breakthrough time and produced water volumes.

The workflow presented in this paper allows for building representative models of fracture networks, which can improve reservoir characterization, flow predictions and reservoir management strategies.
Implementation Study for Miscible Water Alternating Gas (WAG) EOR in a Giant, Offshore Field
Authors: Al Shehhi Budoor , Patel Harshad , Jani Zankar , Khan Sameer
Published: March 2015

The WAG (water-alternating-gas) recovery process is a well-established process for enhanced oil recovery with several successful field applications. This process is evaluated for potential application in a giant, offshore Abu Dhabi field. This paper describes an evaluation approach of the WAG process application to the subject field.

Many separate reservoir simulation models were created to evaluate various aspects of the WAG recovery process. The models addressed WAG operating parameters such as implementation timing, and the effect of WAG parameters (WAG ratio, cycle length). The models were also used to estimate the rate and recovery impact of WAG implementation using different injectants (off-site available hydrocarbon gas, associated gas, enriched gas).

The evaluation process for the giant field started with a small 3D sector model derived from a full-field model of the most significant reservoir unit. This model was extensively used to test the operational parameters. The findings were then tested with larger-scale models for full-field evaluations. Finally, grid sensitivity studies were done using 2D cross-sectional models to calibrate the recovery results from the coarser gridded full-field models.

Results show that WAG incremental recovery over the waterflood recovery for the situations studied is about 7 to 8% OOIP (original-oil-in-place). A WAG ratio of 4:1 appears to be optimal. Incremental WAG recovery is insensitive to cycle lengths and timing of WAG implementation. Miscible injectants provide higher recoveries than immiscible gas injection. Model derived recovery benefits were sensitive to the grid size with as much as twice the likely benefit shown with a coarser grid.
Innovative Permit to Work System - HSE Management in Engineering Manner
Authors: Xingchen ZHOU , Zhang William , Harm David , Jianhua GONG
Published: March 2015

This paper summarizes the successful practice of applying an innovative Permit to Work (PTW) system that has immensely improved the HSE performance of PetroChina Southwest (PCSW).

This system demonstrates how the ‘line’ organisation can effectively and efficiently manage HSE along with its production responsibilities. It has been developed in line with the project management process; organically incorporating Hazard and Effect Management Process (HEMP) principles.

This system differs from a traditional one in term of approaches, roles and responsibilities. Its built-in mechanisms facilitate 100% quality PTW/Job Hazard Analysis (JHA) preparation, precise implementation in the field and continuous improvement of mindset, technical competency and work attitude of staff and contractors.

It has established ‘Best in Class’ JHAs and best practices for quality PTW/JHA preparation, system isolation, gas testing, toolbox talk, verification of safe work conditions, and PTW effectiveness assessment.

Initially developed by the principal Author in 2007, the system was then assessed by the Shell Group Risk and Assurance Manager to be “outstanding and worthy of sharing and adoption more broadly across Shell operations” 1during a global HSSE&SP Audit in October 2008. Its main contents have been introduced to the current Shell Group Permit to Work Manual.

This system has helped a Shell/Sinopec JV to achieve 9 Million Man Hours without Lost Time Injury and 3170 “Goal Zero” Days to the date of 15th October 2014. The Sinopec Group has enforced this system to other ventures. Dozens of Shell coal gasification licensees have adopted it as well.

The current PTW process was updated by its developer in 2012, based on the 2007 version. This new version crystalized upon the successful Shell-PetroChina HSE Cooperation Program. Applying the new PTW system, PCSW has recorded its best HSE performance in their history. Its parent company, PetroChina intends to roll it out across the Group.
Ultrasonic High Resolution Real Time Thickness Combined With High Resolution Multi-Sensor Caliper and CBL Tools in a Single Pass: New Mechanical Well Integrity Logging String Identifies Difficult Casing Problems
Authors: Tello Lucio N. , Lopez Eglee Y. , Azuaje Dimas C.
Published: March 2015

Ultrasonic scanning tools measure the casing thickness by inducing a mechanical resonance of the casing in the thickness mode. At the same time they measure the cement acoustic impedance at higher radial and vertical resolution than sector and segmented tools. A modified Multi-sensor caliper tool measures the casing ID with excellent accuracy and resolution.

A DFT algorithm implemented in the ultrasonic radial scanner tool improves the circumferential and vertical coverage of the thickness over previous methods while widening the measurement range, resolution and accuracy. The algorithm is performed by the tool with more circumferential coverage of the pipe than before. The tool performs this in real time at normal logging speed, thus saving operation and rig time.

When the new ultrasonic radial scanner tool is combined with the new multi-sensor caliper, the magnetic flux-leakage tool, and the CBL in one pass, the tool string generates data that identifies casing damage otherwise difficult to detect with just one of the tools. In addition, the ultrasonic cement impedance measurement and the CBL-VDL (in combination) identify clearly the cement bond conditions. This combination provides comprehensive well mechanical integrity interpretation of the well.

New 3D visualization capabilities of caliper, magnetic flux-leakage, and ultrasonic measurements provide the operator with information to interpret broken or parted casing. This 3D visualization also provides critical information after the remedial work is finished. Discerning whether there is internal or external damage is important information for the operator.

The capability to identify previously undetected casing damage corroborates the new high resolution real time thickness methodology and the improved multi-sensor internal caliper measurements. The four tools in combination provide a valuable method for identifying difficult casing problems.
Exploring the Northern Red Sea – Using Geological Insight and Advanced Geophysical Technologies to Build an Integrated Earth Model for Exploration
Authors: Tulbah Basil , Borsato Ronald , Fox Adam , Snyder Fred , Saragoussi Emmanuel , Cairns Graeme
Published: March 2015

The northeastern Red Sea is part of an active northwest-southeast trending extensional rift basin positioned between the African and Arabian plates. The tectonostratigraphic evolution of the northern Red Sea is largely controlled by phases of differing Arabian plate motion with respect to Africa, which include initial rifting (N55E, ~3.5 mm/yr), initiation of the Dead Sea/Gulf of Aqaba (DSGAT) transform, cessation of rifting in the Gulf of Suez (N20E, ~8.5 mm/yr) and initiation of sea floor spreading and opening of the Gulf of Aqaba (N40E, ~7 mm/yr). Each change in plate motion is characterized by a distinct change in structural orientation and associated sedimentation.

Regional geologic studies and tectonic reconstructions suggest rifting initiated in the northern Red Sea during the early to middle Oligocene (~27-30 Ma). Rifting initiation extended from the Gulf of Aden in the south through the Gulf of Suez and into the present day Nile Delta. In the northern Red Sea, the Arabian plate was moving at approximately 3.5 mm/yr along N55E with respect to Africa; this orientation remained consistent throughout the initial 12-15 million years of rifting. Extension was primarily accommodated along northwest-southeast trending normal faults oriented perpendicular to the regional plate motion direction. Movement along the extensional faults was transferred by northeast-southwest and east-west trending oblique slip faults. Reactivated basement faults of variable orientation also accommodated and transferred extension. The orientation of these structures is consistent with geologic studies of the Gulf of Suez suggesting a common structural evolution for the northeastern Red Sea from 30 to 15 Ma.
Reinterpreting the Low-resistivity Reservoir by Using New Logging Model: A Case Study from a Block in Sulige Tight Gas Field
Authors: Gai Shaohua , Liu Huiqing , He Shunli , Mo Shaoyuan , Lei Gang , Huang Xing , Yang Yang , Liu Ruohan
Published: March 2015

Sulige gas field is the largest discovered gas field so far in China. The pay zone is He8 and Shan1 formation of lower-Permian. The well logging faces the challenges of the thin bed, tight sand and strong lateral heterogeneities, which seriously affected the ability of the well logging data to identify and evaluate gas reservoir. The purpose of this paper is to build up some more accurate models to identify gas layer, water layer, gas and water mixed layer. In this study, the pretreatment have to be done, such as environmental correction, core reposition and well log normalization and so on. Through integrated core, log, test data, models is builded up by using the cross plot multiple regression analysis, including shale content, porosity, permeability, water saturation, etc. The data indicate that the accuracy of the model is 92%.We find that the shale content has a great influence on the porosity model in the block. The characteristic of the gas layer is decreased resistance invasion, and the water layer is increased resistance invasion. Moreover,47 new gas layers are found from 155 wells, and the total increased net pay thickness is 84.5 m. The results accord with the facts basically. By using the results, it can not only optimize the subsequent well logging interpretation design, but also provide the important reservoir information for the researchers of well test and reserves estimation. It is significant to evaluate the subsequent production and allocate reasonable production capacity. Furthermore, it may avoid unnecessary yield loss.
A review on full-scale decentralized wastewater treatment systems: techno-economical approach
Authors: Singh Nitin Kumar , Kazmi A. A. , Starkl M.
Published: March 2015

As a solution to the shortcomings of centralized systems, over the last two decades large numbers of decentralized wastewater treatment plants of different technology types have been installed all over the world. This paper aims at deriving lessons learned from existing decentralized wastewater treatment plants that are relevant for smaller towns (and peri-urban areas) as well as rural communities in developing countries, such as India. Only full-scale implemented decentralized wastewater treatment systems are reviewed in terms of performance, land area requirement, capital cost, and operation and maintenance costs. The results are presented in tables comparing different technology types with respect to those parameters.
Start-up of a full-scale deammonification SBR-treating effluent from digested sludge dewatering
Authors: Lackner Susanne , Thoma Konrad , Gilbert Eva M. , Gander Wolfgang , Schreff Dieter , Horn Harald
Published: March 2015

This study shows the start-up and operation of a full-scale sequencing batch reactor (SBR) with a volume of 550 m³ for deammonification of reject water from sludge dewatering over the first 650 days of operation. The SBR was operated with discontinuous aeration and achieved an optimum of around 85% of ammonium removal at a load of 0.17 kg m−3 d−1. The application of batch tests for the activity measurement of aerobic ammonium and nitrite oxidizing bacteria and anaerobic ammonium oxidizing bacteria were proven to support the identification of setbacks in reactor operation. Furthermore, the calculation of the oxygen uptake rates from online oxygen measurements helped to explain the overall reactor performance. The aeration regime is a key parameter for stable operation of such an SBR for deammonification. At aeration/non-aeration time ranges from 6–9 min, the best results with respect to turnover rates and low nitrate production were achieved. Compared with the nitrification/denitrification SBR operated in parallel with methanol as the carbon source, a significant reduction in costs for energy and chemicals was achieved. The costs for maintenance slightly increased.
A full-scale plug-flow reactor for biological sludge ozonation
Authors: Gardoni Davide , Ficara Elena , Vergine Pompilio , Canziani Roberto
Published: March 2015

The reduction of biological excess sludge production using ozone is a well-known technology and is applied in several full-scale plants around the world. Nevertheless, optimisation of the process is not yet adequately documented in the literature. Operational parameters are usually chosen by assuming a direct proportionality between ozone dose and excess sludge reduction. This paper investigates the role of ozone concentration on process efficiency and demonstrates the (non-linear) inverse relationship between ozone dose and specific particulate chemical oxygen demand solubilisation in plug-flow contact reactors. The influence of total suspended solids concentration is also studied and described. No short-term lethal effects on heterotrophic biomass have been observed.
Arsenic and antimony removal from drinking water by adsorption on granular ferric oxide
Authors: Sazakli Eleni , Zouvelou Stavroula V. , Kalavrouziotis Ioannis , Leotsinidis Michalis
Published: March 2015

Arsenic and antimony occur in drinking water due to natural weathering or anthropogenic activities. There has been growing concern about their impact on health. The aim of this study was to assess the efficiency of a granular ferric oxide adsorbent medium to remove arsenic and antimony from drinking water via rapid small-scale column tests (RSSCTs). Three different water matrices – deionized, raw water treated with a reverse osmosis domestic device and raw water – were spiked with arsenic and/or antimony to a concentration of 100 μg L−1. Both elements were successfully adsorbed onto the medium. The loadings until the guideline value was exceeded in the effluent were found to be 0.35–1.63 mg g−1 for arsenic and 0.12–2.11 mg g−1 for antimony, depending on the water matrix. Adsorption of one element was not substantially affected by the presence of the other. Aeration did not affect significantly the adsorption capacity. Granular ferric oxide could be employed for the simultaneous removal of arsenic and antimony from drinking water, whereas full-scale systems should be assessed via laboratory tests before their implementation.
Comparison of reverse osmosis membrane fouling characteristics in full-scale leachate treatment systems with chemical coagulation and microfiltration pre-treatments
Authors: Rukapan Weerapong , Khananthai Benyapa , Srisukphun Thirdpong , Chiemchaisri Wilai , Chiemchaisri Chart
Published: March 2015

Fouling characteristics of reverse osmosis (RO) membrane with chemical coagulation and microfiltration (MF) pre-treatment were investigated at full-scale leachate treatment systems. In chemical coagulation pre-treatment, solid separation from stabilized leachate was performed by ferric chloride coagulation followed by sand filtration. Meanwhile, MF pre-treatment and the RO system utilized direct filtration using a 0.03 µm membrane without chemical addition. MF pre-treatment yielded better pollutant removals in terms of organics and nitrogen. The study on effect of pre-treatment on RO membrane fouling revealed that accumulated foulant on the RO membrane in MF pre-treatment was significantly lower than that of chemical coagulation. Nevertheless, NaOH cleaning of the fouled RO membrane after chemical coagulation pre-treatment could better recover its permeate flux, thus suggesting that the formation of a loose-structure cake layer by chemical coagulation pre-treatment could allow effective penetration of chemical cleaning and detachment of foulant layer from the membrane surface.
Water quantity and quality assessment on a tertiary treatment wetland in a tropical climate
Authors: Sun Guangzhi , Saeed Tanveer , Zhang Guangxin , Sivakugan Nagaratnam
Published: March 2015

This study aimed to assess the quantity and quality of water in a surface flow constructed wetland in Australia's far north Queensland. Owing to tropical climate in the region, the wetland provided dual functions: retention of a treated wastewater for zero discharge during the dry season and tertiary treatment prior to discharge during the wet season. Rainfall data, permeability of wetland soil, evaporation, inflow and outflow were analysed in a water balance analysis; the results showed that based on a 72-year-average rainfall pattern, daily wastewater inflow of 85 m3/d is the maximum this wetland can cope with without breaching its discharge certificate. In water quality analysis, the K-C* model was used to predict changes of biochemical oxygen demand (BOD, suspended solids (SS), total nitrogen (TN), total phosphorus (TP) and faecal coliforms (FC) in the wetland. Model predictions were compared with field sampling results. It was found that the wetland was effective in removing FC (>99.9%), TN (70.7%) and TP (68.2%), for which the predictions by the K-C* model were consistent with field testing results. However, significant disparities between the predictions and testing results were found for BOD and SS. A revised K-C* equation was proposed to account for the internal generation of organics in constructed wetlands with a long retention time.
The practical influence of rapid mixing on coagulation in a full-scale water treatment plant
Authors: Allerdings Demitri , Förster Gerrit , Vasyukova Ekaterina , Uhl Wolfgang
Published: March 2015

This study focuses on the effect of rapid mixing on the coagulation efficiency in a full-scale drinking-water treatment plant and discusses the mechanisms involved in the floc-formation process. The results refer to three periods of operation of the waterworks when no mechanical mixing was provided in the tanks for coagulant dosing due to mechanical failure of the rapid mixers. Although a certain deterioration of the subsequent flocculation process was observed, as assessed using the data for suspended solids, turbidity, and chemical oxygen demand, the overall water treatment performance was not affected. This suggests an insignificant role for intense rapid mixing in sweep flocculation during full-scale water treatment and reveals the potential to reduce the required energy costs for mechanical mixers.
Anaerobic/aerobic treatment of greywater via UASB and MBR for unrestricted reuse
Authors: Abdel-Shafy Hussein I. , Al-Sulaiman Ahmed Makki , Mansour Mona S. M.
Published: March 2015

The aim of the present study was to investigate the efficiency of integrated up-flow anaerobic sludge blanket (UASB) as anaerobic system followed by membrane bioreactor (MBR) as aerobic system for the treatment of greywater for unrestricted reuse. Pilot-scale UASB and MBR units were installed and operated in the NRC, Egypt. Real raw greywater was subjected to UASB and the effluent was further treated with microfiltration MBR. The necessary trans-membrane pressure difference is applied by the water head above the membrane (gravity flow) without any energy input. The average characteristics of the raw greywater were 95, 392, 298, 10.45, 0.4, 118.5 and 28 mg/L for total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total phosphates, nitrates, oil and grease, and total Kjeldahl nitrogen (TKN), respectively. The pH was 6.71. The UASB treatment efficiency reached 19.3, 57.8, 67.5 and 83.7% for TSS, COD, BOD5 and oil and grease, respectively. When the UASB effluent was further treated with MBR, the overall removal rate achieved 97.7, 97.8, 97.4 and 95.8% for the same parameters successively. The characteristics of the final effluent reached 2.5, 8.5, 6.1, 0.95, 4.6 and 2.3 mg/L for TSS, COD, BOD, phosphates, oil and grease and TKN, respectively. This final treated effluent could cope with the unrestricted water reuse of local Egyptian guidelines.
Full-scale phosphorus recovery from digested waste water sludge in Belgium – part I: technical achievements and challenges
Authors: Marchi A. , Geerts S. , Weemaes M. , Wim S. , Christine V.
Published: March 2015

To date, phosphorus recovery as struvite in wastewater treatment plants has been mainly implemented on water phases resulting from dewatering processes of the sludge line. However, it is possible to recover struvite directly from sludge phases. Besides minimising the return loads of phosphorus from the sludge line to the water line, placing such a process within the sludge line is claimed to offer advantages such as a higher recovery potential, enhanced dewaterability of the treated sludge, and reduced speed of scaling in pipes and dewatering devices. In the wastewater treatment plant at Leuven (Belgium), a full-scale struvite recovery process from digested sludge has been tested for 1 year. Several monitoring campaigns and experiments provided indications of the efficiency of the process for recovery. The load of phosphorus from the sludge line returning to the water line as centrate accounted for 15% of the P-load of the plant in the reference situation. Data indicated that the process divides this phosphorus load by two. An improved dewaterability of 1.5% of dry solids content was achieved, provided a proper tuning of the installation. Quality analyses showed that the formed struvite was quite pure.
Levels of gingival crevicular fluid matrix metalloproteinases in periodontally compromised teeth under orthodontic forces
Authors: Almeida Rhita C. , Capelli Jonas , Teles Ricardo P.
Published: March 2015

Objective: 

To examine levels of matrix metalloproteinases (MMPs)-1, -2, -3, -7, -8, -12, and -13 in the gingival crevicular fluid (GCF) of periodontally compromised teeth at different time points during orthodontic movement.

Materials and Methods: 

Ten controlled periodontitis subjects were submitted to orthodontic treatment. One dental arch was subjected to orthodontic movement, and teeth in the opposite arch were used as controls. GCF samples were collected from the lingual sites of two movement and two control incisors 1 week before orthodontic activation (−7 d), immediately after orthodontic activation, and after 1 hour, 24 hours, and 7, 14, and 21 days. Multiplexed bead immunoassay was used to measure MMPs in GCF. Data were analyzed using Friedman and Wilcoxon statistical tests.

Results: 

The only significant change found over time was in the levels of MMP-1 in the movement group (P < .05). When the two groups were compared after activation, the only statistically significant difference found was in levels of MMP-12 24 hours after activation (P < .05).

Conclusions: 

Our findings suggested that the orthodontic movement of periodontally compromised teeth without active pockets did not result in significant changes in the GCF levels of MMPs.
Methylation Status of the Chromosome Arm 19q MicroRNA Cluster in Sporadic and Androgenetic-Biparental Mosaicism–Associated Hepatic Mesenchymal Hamartoma
Authors: Keller Rachel B. , El Demellawy Dina , Quaglia Alberto , Finegold Milton , Kapur Raj P.
Published: March 2015

The C19MC gene on chromosome band 19q13.4 encodes a cluster of 46 microRNAs; those microRNAs are normally only expressed from the paternal allele and in the placenta. Placental expression correlates with selective demethylation of the paternal C19MC promoter, in contrast to methylation of both maternal and paternal alleles in nonplacental tissues. Prior investigations demonstrated “ectopic” activation of this gene in most hepatic mesenchymal hamartomas, including sporadic tumors and others with androgenetic-biparental mosaicism (subset of cells are diploid, but contain only paternally derived chromosomes). In the present investigation of C19MC promoter methylation status in a series of 14 mesenchymal hamartomas, a demethylated allele was identified in 6 tumors, including all 4 with androgenetic-biparental mosaicism. Conversely, only methylated alleles were cloned from sporadic hamartomas, including 3 tumors with chromosomal rearrangements thought likely to activate C19MC expression independent of the native promoter. In conjunction with published data, the findings suggest multiple molecular mechanisms for C19MC activation in hepatic mesenchymal hamartoma, including the existence of a normal placental imprinting pattern in mesenchymal cells in a subset of cases. Some or all of the latter hamartomas may result from placental “grafting,” a hypothesis supported by endothelial expression of the placental vascular marker, glucose transporter-1, in 1 of the 6 cases with a demethylated allele.
New LA-ICP-MS cryocell and calibration technique for sub-millimeter analysis of ice cores
Authors: Sneed Sharon B. , Mayewski Paul A. , Sayre W.G. , Handley Michael J. , Kurbatov Andrei V. , Taylor Kendrick C. , Bohleber Pascal , Wagenbach Dietmar , Erhardt Tobias , Spaulding Nicole E.
Published: March 2015

Ice cores provide a robust reconstruction of past climate. However, development of timescales by annual-layer counting, essential to detailed climate reconstruction and interpretation, on ice cores collected at low-accumulation sites or in regions of compressed ice, is problematic due to closely spaced layers. Ice-core analysis by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) provides sub-millimeter-scale sampling resolution (on the order of 100 μm in this study) and the low detection limits (ng L−1) necessary to measure the chemical constituents preserved in ice cores. We present a newly developed cryocell that can hold a 1 m long section of ice core, and an alternative strategy for calibration. Using ice-core samples from central Greenland, we demonstrate the repeatability of multiple ablation passes, highlight the improved sampling resolution, verify the calibration technique and identify annual layers in the chemical profile in a deep section of an ice core where annual layers have not previously been identified using chemistry. In addition, using sections of cores from the Swiss/Italian Alps we illustrate the relationship between Ca, Na and Fe and particle concentration and conductivity, and validate the LA-ICP-MS Ca profile through a direct comparison with continuous flow analysis results.
An Experimental Examination of the Interaction between Mood Induction Task and Personality Psychopathology on State Emotion Dysregulation
Authors: Borges Lauren , Naugle Amy
Published: March 2015

While emotion dysregulation has been investigated as a key variable in the development and persistence of personality psychopathology, few studies have explored state emotion dysregulation among individuals with personality disorders (PDs). The current study addresses this void in the literature through a laboratory investigation of state emotion dysregulation among participants with and without PDs. To facilitate this goal, participants were matched to pairs based on similar personality features and were randomized to one of two behavioral analogues; either the Paced Auditory Serial Addition Task-Computerized (PASAT-C) or an interpersonally based mood induction. As hypothesized, PD participants in the PASAT-C reported significantly more difficulty with impulsivity and emotion regulation strategies. Contrary to expectations, the PD group in the interpersonal task demonstrated significantly less difficulty with non-acceptance of emotion and emotional clarity and significantly greater positive affect compared to non-PD participants. Implications for these findings and directions for future research are discussed.
Is Black Always the Opposite of White? An Investigation on the Comprehension of Antonyms in People with Schizophrenia and in Healthy Participants
Authors: Cacciari Cristina , Pesciarelli Francesca , Gamberoni Tania , Ferlazzo Fabio , Russo Leo , Pedrazzi Francesca , Melati Ermanno
Published: March 2015

The present investigation sought to expand our understanding of the cognitive processes underlying the recognition of antonyms and to evaluate whether these processes differed in patients with schizophrenia and in healthy controls. Antonymy is the most robust of the lexico-semantic relations and is relevant to both the mental organization of the lexicon and the organization of coherent discourse, as attested by the resurgence of interest in antonymy in the linguistic and psychological domains. In contrast, the vast literature on semantic processing in schizophrenia almost ignored antonymy. In this study, we tested the online comprehension of antonyms in 39 Italian patients with paranoid schizophrenia and in an equal number of pairwise-matched healthy controls. Participants read a definitional sentence fragment (e.g., the opposite of black is), followed by the correct antonym (white) or by a semantically unrelated word (nice), and judged whether or not the target word was correct. Patients were rather accurate in identifying antonyms, but compared to controls, they showed longer response times and higher priming scores, suggesting an exaggerated contextual facilitation. Presumably, this reflects a deficient controlled semantic processing and an overreliance on stored semantic representations.
Nanoparticle Filtration Characteristics of Advanced Metal Foam Media for a Spark Ignition Direct Injection Engine in Steady Engine Operating Conditions and Vehicle Test Modes
Authors: Myung Cha-Lee , Kim Juwon , Jang Wonwook , Jin Dongyoung , Park Simsoo , Lee Jeongmin
Published: March 2015

In this study, the particle formation and reduction characteristics at the engine-out position, after a three-way catalyst (TWC) and a metal foam gasoline particulate filter (GPF), were evaluated for a gasoline direct-injection (GDI) engine under part-load operating conditions. The vehicle tests were performed under the Federal Test Procedure-75 (FTP-75) and the Highway Fuel Economy Test (HWFET) modes. Particle number (PN) concentrations, size distributions, and the filtering efficiency with the GPF were evaluated with a condensation particle counter (CPC) and a differential mobility spectrometer (DMS500). Under steady engine operating conditions, the PN concentrations at the engine-out position were 9.7 × 105–2.5 × 106 N/cc. While, the PN concentrations after the GPF were 9.2 × 104–3.5 × 105 N/cc, and the PN was reduced by 77%–96%. The PN filtering efficiency with the GPF-GDI vehicle reached approximately 58% in the FTP-75 and 62% in the HWFET mode. The PN concentration of the GPF-GDI vehicle was significantly reduced to 3.95 × 1011 N/km for the FTP-75 and 8.86 × 1010 N/km for the HWFET mode. The amount of nucleation mode particles below 23 nm was substantially reduced with the GPF-GDI vehicle. The fuel economy, CO2, and regulated emissions of the GPF-GDI vehicle were equivalent to those of the base GDI vehicle under the vehicle certification modes.
Species-Dependent Splice Recognition of a Cryptic Exon Resulting from a Recurrent Intronic CEP290 Mutation that Causes Congenital Blindness
Authors: Garanto Alejandro , Duijkers Lonneke , Collin Rob
Published: March 2015

A mutation in intron 26 of CEP290 (c.2991+1655A>G) is the most common genetic cause of Leber congenital amaurosis (LCA), a severe type of inherited retinal degeneration. This mutation creates a cryptic splice donor site, resulting in the insertion of an aberrant exon (exon X) into ~50% of all CEP290 transcripts. A humanized mouse model with this mutation did not recapitulate the aberrant CEP290 splicing observed in LCA patients, suggesting differential recognition of cryptic splice sites between species. To further assess this phenomenon, we generated two CEP290 minigene constructs, with and without the intronic mutation, and transfected these in cell lines of various species. RT-PCR analysis revealed that exon X is well recognized by the splicing machinery in human and non-human primate cell lines. Intriguingly, this recognition decreases in cell lines derived from species such as dog and rodents, and it is completely absent in Drosophila. In addition, other cryptic splicing events corresponding to sequences in intron 26 of CEP290 were observed to varying degrees in the different cell lines. Together, these results highlight the complexity of splice site recognition among different species, and show that care is warranted when generating animal models to mimic splice site mutations in vivo.
Trans-Membrane Area Asymmetry Controls the Shape of Cellular Organelles
Authors: Beznoussenko Galina , Pilyugin Sergei , Geerts Willie , Kozlov Michael , Burger Koert , Luini Alberto , Derganc Jure , Mironov Alexander
Published: March 2015

Membrane organelles often have complicated shapes and differ in their volume, surface area and membrane curvature. The ratio between the surface area of the cytosolic and luminal leaflets (trans-membrane area asymmetry (TAA)) determines the membrane curvature within different sites of the organelle. Thus, the shape of the organelle could be critically dependent on TAA. Here, using mathematical modeling and stereological measurements of TAA during fast transformation of organelle shapes, we present evidence that suggests that when organelle volume and surface area are constant, TAA can regulate transformation of the shape of the Golgi apparatus, endosomal multivesicular bodies, and microvilli of brush borders of kidney epithelial cells. Extraction of membrane curvature by small spheres, such as COPI-dependent vesicles within the Golgi (extraction of positive curvature), or by intraluminal vesicles within endosomes (extraction of negative curvature) controls the shape of these organelles. For instance, Golgi tubulation is critically dependent on the fusion of COPI vesicles with Golgi cisternae, and vice versa, for the extraction of membrane curvature into 50–60 nm vesicles, to induce transformation of Golgi tubules into cisternae. Also, formation of intraluminal ultra-small vesicles after fusion of endosomes allows equilibration of their TAA, volume and surface area. Finally, when microvilli of the brush border are broken into vesicles and microvilli fragments, TAA of these membranes remains the same as TAA of the microvilli. Thus, TAA has a significant role in transformation of organelle shape when other factors remain constant.
Comparison of Mutation Profiles in the Duchenne Muscular Dystrophy Gene among Populations: Implications for Potential Molecular Therapies
Authors: López-Hernández Luz , Gómez-Díaz Benjamín , Luna-Angulo Alexandra , Anaya-Segura Mónica , Bunyan David , Zúñiga-Guzman Carolina , Escobar-Cedillo Rosa , Roque-Ramírez Bladimir , Ruano-Calderón Luis , Rangel-Villalobos Héctor , López-Hernández Julia , Estrada-Mena Francisco , García Silvia , Coral-Vázquez Ramón
Published: March 2015

Novel therapeutic approaches are emerging to restore dystrophin function in Duchenne Muscular Dystrophy (DMD), a severe neuromuscular disease characterized by progressive muscle wasting and weakness. Some of the molecular therapies, such as exon skipping, stop codon read-through and internal ribosome entry site-mediated translation rely on the type and location of mutations. Hence, their potential applicability worldwide depends on mutation frequencies within populations. In view of this, we compared the mutation profiles of the populations represented in the DMD Leiden Open-source Variation Database with original data from Mexican patients (n = 162) with clinical diagnosis of the disease. Our data confirm that applicability of exon 51 is high in most populations, but also show that differences in theoretical applicability of exon skipping may exist among populations; Mexico has the highest frequency of potential candidates for the skipping of exons 44 and 46, which is different from other populations (p < 0.001). To our knowledge, this is the first comprehensive comparison of theoretical applicability of exon skipping targets among specific populations.
Monitoring of Apoptosis in 3D Cell Cultures by FRET and Light Sheet Fluorescence Microscopy
Authors: Weber Petra , Schickinger Sarah , Wagner Michael , Angres Brigitte , Bruns Thomas , Schneckenburger Herbert
Published: March 2015

Non-radiative cell membrane associated Förster Resonance Energy Transfer (FRET) from an enhanced cyan fluorescent protein (ECFP) to an enhanced yellow fluorescent protein (EYFP) is used for detection of apoptosis in 3-dimensional cell cultures. FRET is visualized in multi-cellular tumor spheroids by light sheet based fluorescence microscopy in combination with microspectral analysis and fluorescence lifetime imaging (FLIM). Upon application of staurosporine and to some extent after treatment with phorbol-12-myristate-13-acetate (PMA), a specific activator of protein kinase c, the caspase-3 sensitive peptide linker DEVD is cleaved. This results in a reduction of acceptor (EYFP) fluorescence as well as a prolongation of the fluorescence lifetime of the donor (ECFP). Fluorescence spectra and lifetimes may, therefore, be used for monitoring of apoptosis in a realistic 3-dimensional system, while light sheet based microscopy appears appropriate for 3D imaging at low light exposure.
A Heme Oxygenase-1 Transducer Model of Degenerative and Developmental Brain Disorders
Authors: Schipper Hyman , Song Wei
Published: March 2015

Heme oxygenase-1 (HO-1) is a 32 kDa protein which catalyzes the breakdown of heme to free iron, carbon monoxide and biliverdin. The Hmox1 promoter contains numerous consensus sequences that render the gene exquisitely sensitive to induction by diverse pro-oxidant and inflammatory stimuli. In “stressed” astroglia, HO-1 hyperactivity promotes mitochondrial iron sequestration and macroautophagy and may thereby contribute to the pathological iron deposition and bioenergetic failure documented in Alzheimer disease, Parkinson disease and certain neurodevelopmental conditions. Glial HO-1 expression may also impact neuroplasticity and cell survival by modulating brain sterol metabolism and the proteasomal degradation of neurotoxic proteins. The glial HO-1 response may represent a pivotal transducer of noxious environmental and endogenous stressors into patterns of neural damage and repair characteristic of many human degenerative and developmental CNS disorders.
Evidence of Aortopathy in Mice with Haploinsufficiency of Notch1 in Nos3-Null Background
Authors: Koenig Sara , Bosse Kevin , Nadorlik Holly , Lilly Brenda , Garg Vidu
Published: March 2015

Thoracic aortic aneurysms (TAA) are a significant cause of morbidity and mortality in humans. While the exact etiology is unknown, genetic factors play an important role. Mutations in NOTCH1 have been linked to bicuspid aortic valve (BAV) and aortopathy in humans. The aim of this study was to determine if haploinsufficiency of Notch1 contributes to aortopathy using Notch1+/−; Nos3−/− mice. Echocardiographic analysis of Notch1+/−; Nos3−/− mice reveals effacement of the sinotubular junction and a trend toward dilation of the aortic sinus. Furthermore, examination of the proximal aorta of Notch1+/−; Nos3−/− mice reveals elastic fiber degradation, a trend toward increased matrix metalloproteinase 2 expression, and increased smooth muscle cell apoptosis, features characteristic of aneurysmal disease. Although at a lower penetrance, we also found features consistent with aortopathic changes in Notch1 heterozygote mice and in Nos3-null mice. Our findings implicate a novel role for Notch1 in aortopathy of the proximal aorta.
Hypercalcemia Associated with Calcium Supplement Use: Prevalence and Characteristics in Hospitalized Patients
Authors: Machado Maria , Bruce-Mensah Araba , Whitmire Melanie , Rizvi Ali
Published: March 2015

Background: The ingestion of large amounts of milk and antacids to treat peptic ulcer disease was a common cause of hypercalcemia in the past (the “milk-alkali syndrome”). The current popularity of calcium and supplements has given rise to a similar problem. Objectives: To evaluate the prevalence and characteristics of hypercalcemia induced by calcium intake (“calcium supplement syndrome”; or CSS) in hospitalized patients. Methods: We conducted a retrospective; electronic health record (EHR)-based review of patients with hypercalcemia over a 3-year period. Diagnosis of CSS was based on the presence of hypercalcemia; a normal parathyroid hormone (PTH) level; renal insufficiency; metabolic alkalosis; a history of calcium intake; and documented improvement with treatment. Results: Of the 72 patients with non-PTH mediated hypercalcemia; 15 (20.8%) satisfied all the criteria for the diagnosis of CSS. Calcium; vitamin D; and multivitamin ingestion were significantly associated with the diagnosis (p values < 0.0001; 0.014; and 0.045 respectively); while the presence of hypertension; diabetes; and renal insufficiency showed a trend towards statistical significance. All patients received intravenous fluids; and six (40%) received calcium-lowering drugs. The calcium level at discharge was normal 12 (80%) of patients. The mean serum creatinine and bicarbonate levels decreased from 2.4 and 35 mg/dL on admission respectively; to 1.6 mg/dL and 25.6 mg/dL at discharge respectively. Conclusion: The widespread use of calcium and vitamin D supplementation can manifest as hypercalcemia and worsening of kidney function in susceptible individuals. Awareness among health care professionals can lead to proper patient education regarding these health risks.