bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Predictive Emission Monitoring System Algorithms for Qatargas Turbine
Authors: Suliono Andi , Sadois Claude , Raja Mohsin , Baldwin James
Published: May 2012

Qatargas Operating Company Limited (Qatargas) and Total Research Center Qatar (TRC-Q) established a collaboration to study Predictive Emissions Monitoring System (PEMS) algorithms for pilot application on a Qatargas turbine to predict NOx emissions. The approach for this Pilot Study was a blind benchmarking comparison of three main PEMS algorithms (first principle, statistical and neural networks) to define the most appropriate one(s) for application at the pilot gas turbine. This study was intended to demonstrate to local authorities that PEMS can be a reliable monitoring technique in both an alternative or complimentary capacity to CEMS.

The assessment of PEMS models developed as part of this study and their corresponding performance will be discussed in a separate paper when the study is completed. This initial paper describes the challenges and lessons learned during the preparatory phase of PEMS model development. It describes the importance of a well-planned preparatory stage as this significantly affects the quality and validity of collected turbine operational and emissions data for PEMS model construction.

It is important to undertake internal quality assurance checks on collected operational and monitored emissions data prior to model development. This paper describes the important role played by maintenance and calibration of measuring instruments such as stack emissions analyzers in ensuring reliability and accuracy of measured data. To build robust PEMS models, individual correlations between NOx emissions and various turbine operational parameters need to be assessed in the preparatory stage.

The PEMS models developed for the pilot turbine were initiated on an incremental basis using variables with significant correlation and then optimized using other secondary parameters to improve correlation between the predicted and measured NOx emissions. This paper notes that the influence of turbine operational parameter on NOx emissions varies depending on its role in the formation of NOx as part of the combustion process. These include fuel gas composition and flow rate, as well as ambient air temperature and humidity.
Thermal Stability of Various Chelates that are used in the Oilfield and Potential Damage Due to their Decomposition Products
Authors: Sokhanvarian Khatere , Nasr-El-Din H. A. , Wang Guanqun , De-Wolf C. A.
Published: May 2012

Chelating agents are used to remove various inorganic scales, including sulfates and carbonates. They are also used as stand-alone stimulation fluids and as iron control agents during acidizing treatments. The main chelating agents used in the field, include: ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), N-(hydroxyethyl)-ethylenediamineteriaacetic acid (HEDTA), and recently, L- glutamic acid-N, N diacetic acid (GLDA). One of the concerns with these chelates is their thermal stability at elevated temperatures. A few studies examined the thermal stability of these chelating agents, and the impact of thermal degradation products on permeability. The objectives of the present study are to: 1) Examine the thermal stability of several chelating agents and their salts up to 450°F, and 2) assess the effect of thermal decomposition products on the permeability of carbonate and sandstone cores with different initial permeabilities.

We prepared solutions (0.4 to 0.6 M) of HEDTA, GLDA, NTA, EDTA and their salts. The solutions of these chelates were heated at various temperatures and times (2 to 12 hrs.). The concentration of chelate was determined using a new analytical technique that was based on titration with FeCl3. The products of thermal decomposition of chelates were determined using MS technique.

Core flood tests were conducted on Berea sandstone and Indiana limestone to determine the effect of thermal degradation products on the permeability of these cores. Coreflood tests were conducted at 325°F and 3 cm3/min.

Most chelates decomposed at temperatures greater than 350°F. Among monovalent salts, potassium salt was found to be the most stable one. Chelates with two nitrogen atoms were more stable than those with one nitrogen atom. For example, diammonium salt of EDTA is more stable than diammonium salt of GLDA. Analyses of chelate solutions after heating using MS technique highlighted that the decomposition products included: iminodiacetic acid, formic acid, and α-hydroxy acids. Results of the coreflood indicated that some of the thermal decomposition products can cause formation damage. This paper will summarize the results obtained, and explain how chelates can be used to improve field treatments, especially at high temperatures.
Optimization of Limited Entry Matrix Acid Stimulations with Laboratory Testing and Treatment Pressure Matching
Authors: Van Domelen Mary S. , abd Hammoud Mohamad , Glasbergen Gerard , Talib Noor
Published: May 2012

In the Danish Central Graben, tight chalk reservoirs have been successfully developed through drilling, completion and stimulation of long horizontal wells. One of the most successful technologies which has opened access to the far reaches of several major fields is the Controlled Acid Jetting (CAJ) technique. CAJ treatments are performed with a treatment pressure at formation below fracturing pressure and at the maximum rate possible. Diversion is via maximum rate/pressure, combined with the limited entry technique; therefore diversion stages are not normally included in CAJ treatments. A horizontal CAJ completion may range from 5,000 ft to as long as 20,000 ft, but is most often on the order of 10,000 ft. Acid coverage is normally 1 bbl/ft of 15% HCl. Injection rates as high as 40-50 BPM are often required to ensure complete coverage of the CAJ liner.

There are still areas to be investigated to maintain an effective optimization of the CAJ technology. One of these areas to be investigated is the frictional pressure drop across the perforations (ΔPperf), which is influenced by the perforation coefficient (Cp). Usually in the design and operation of the stimulation, Cp is assigned a specific value when calculating the pressure drop across the perforations. Field experience and previous studies discovered that the Cp may change due to the viscosity of the fluid injected.

This paper will present the results of a study of the perforation coefficient through laboratory experiments. A set-up for measuring the pressure drop across an orifice for different types of fluids at different flow rates was constructed. The perforation pressure drops were measured and then used to calculate the fluid specific Cp in order to clarify any changes in relation to the viscosity.

The results of the laboratory study are utilized in a real-time CAJ stimulation diagnostic tool which has been used in several different chalk formations. The predicted acid coverage of the long CAJ liners is shown to be very sensitive to the assumed value of Cp. Overall, the outcome of this project was considered as a further contribution to the process of achieving a better understanding of the CAJ stimulation in general and about the impact of the perforation coefficient in specific.
The Impact of TAN from Heavy Oil EOR to Operation and Integrity: Case Study
Authors: Nengkoda Ardian
Published: May 2012

The reserve of conventional oil is decreasing as a trend and it is leading to the price hikes for conventional crude. Finding alternative energy sources including heavy oil is therefore a major agenda of the day. Thus there is an incentive to explore the heavy oil with a priority. One of the major issues dealing with heavy oil production is TAN (Total Acid Number) from crude oil. What is the impact of TAN to flow assurance? The value of crude oils is often dependent on the corrosivity of the oil, and corrosivity is mainly a function of the total acid number of the oil. TAN, in turn, is heavily dependent, although not completely so, on the naphthenic acid concentration of the oil. Consequently, crudes having a relatively high TAN, e.g., ≥2 have a significantly lower market value, on a per barrel basis, than crudes having a relatively lower TAN. The current approach to refine acidic crudes is to blend the acidic crudes with non-acidic crudes, so that the TAN of the blend is no higher than about 0.5. The case study have been conducted to predict the overall mix of crude TAN in main oil line and see the impact of TAN from heavy oil steam EOR operation in Oman. The workflow are covering: set up and define laboratory testing to see the root cause of TAN and the impact of heavy oil EOR crude to overall field, develop a worst case scenario and selecting the other alternative to lowering TAN. For example, the first basic strategy in managing TAN, high TAN crudes are often blended off with lower TAN crudes, the second strategy is to injecting some TAN reducing chemicals. Finally, the techno-economic matrix will help the decision of managing TAN.
The Design, Implementation and Use of Inflow Control Devices for Improving the Production Performance of Horizontal Wells
Authors: Minulina Polina , Al-Sharif Shahin , Zeito George , Bouchard Michel
Published: May 2012

The use of horizontal and multilateral wells in heterogeneous reservoirs has become well established over the last 10–15 years and has resulted in improved recovery and increased field life. Due to the non-uniform influx from these wells, less than 1/3 of the lateral contributes the bulk of the production from the well. The presence of an aquifer or gas cap can significantly shorten the well life and make it uneconomical. This is especially true for offshore fields where well intervention is difficult and expensive.

The use of ICD's or inflow Control Devices is becoming more prevalent and can result in significantly increasing the economic life of a well. Most of the devices currently in use are passive and once set, cannot be changed or modified. ICD's can be used for both producers and injectors and are very effective when used in conjunction. Prior to completing a well with ICD's, considerable design work needs to be done to determine the optimal settings for the life of the well. In order to properly design the ICD configuration, extensive simulations are required from the newly drilled well properties. A poorly designed well can result in choking production from good reservoir sections or resulting in early breakthrough. This paper discusses the different types of ICD's available and the process to properly design the well completion. The different modeling tools available are presented and the implementation process in the field reviewed. Two field examples are given and the results from these installations presented. A process for the proper design and common issues are also presented. The use of screens coupled with ICD's for sand control is also discussed.
The Role of Calcite in CO2 Increase 25% During Cyclic Steam Injection in Sandstone Heavy Oil Reservoir: Case Study
Authors: Nengkoda Ardian
Published: May 2012

Cyclic steam EOR pilot project has been deployed in sandstone reservoir type, heavy oil field of Petroleum Development Oman, South Operation, and recently within August to October 2011 showing an interesting CO2 increase from 1% to the level of 25% mol in gas phase as phenomena. This paper discuss the implementation of Root Cause Analysis, developing steam core flood techniques to understand the increasing mechanism of CO2, and the proactive well surveillance will help to monitor accurately the increasing level and the impact. The impact of high CO2 to well and operation integrity also have been studied. The Low GOR (<25 scf/bbl) found to be a limitation of reservoir, while the heavy oil characteristics 14 API will limit a level increase from the well. The only possible CO2 increased are coming from a thermal evaporation mechanism of formation water and rock mineralogy. The basis simplified chemistry model have been developed as steam energy reaction, one mole of CO2 was produced for each mole of H2O injected at steam temperatures. From the detail mineralogy study found that the sandstone reservoir from the field containing Dolomite and Calcite. The surface CO2 found to be the total amount of evaporation from rock mineralogy, Calcite from formation water and from origin associate reservoir gas. And finally, the CO2 percentage increase in the surface will be less than 3 scf/bbl.
Qatar Shell GTL Implementation of Process Safety Management
Authors: Johnson Andy D.
Published: May 2012

This paper will contains details of the following aspects of Qatar Shell GTL limited's implementation of process safety management.

The business case for Process Safety Management

The continuing incidence of major industrial accidents has driven the recognition that management of process safety requires a different approach from the management of occupational safety.

Process Safety in Design, ALARP Demonstration and the Design HSE Case

Process Safety Management begins with the design of facilities. The paper describes how Shell uses the Hazards and Effects Management Process to identify process safety hazards, assess their risks and manage them to be As Low As Reasonably Practicable (ALARP) at each stage of the Design of oil and gas facilities, and the formal record of this process in a Design HSE Case.

Process Safety Management in Operations – The Operations HSE Case

The paper will describe how the Operations HSE Case is used to continue the management of process safety in operations. The use of a Hazard Register to record the hazards present during operations and the selection of those hazards with high process safety risks. The use of Bowties to record threats that can lead to loss of containment or control and the barriers (either hardware or task related) used to prevent or recover from such loss. The link between the barriers and the operational activities required to maintain those barriers during the lifetime of a facility.

Instilling the right behaviours in Process Safety Management - Chronic Unease

Challenging the risk management of major accidents requires a retuned leadership mindset, so that leaders ask the right questions, and pick up on the weak signals of potential failure. The paper describes what Shell leaders are doing to improve awareness and focus on process safety.
Editorial
Authors: Mom Gijs , Clarsen Georgine , Seiler Cotten
Published: May 2012

At Eindhoven University of Technology, which has a modest reputation for collecting contemporary art, an exhibition of large machines and poetic video clips by father and son Van Bakel invites passersby to reflect on mobility. Gerrit van Bakel, who died more than a quarter century ago, became known for his Tarim Machine, a vehicle that moves at such a low speed that it almost does not matter whether it moves or not. The propulsion principle—for those who love technology—rests on the dilatation energy of oil in tubes propelling (if propelling is the right word …) the contraption a couple of centimeters over a hundred years or so, as long as there is change in temperature to trigger the dilatation. Emphasizing his father’s insights, Michiel van Bakel, exhibits a video clip of a horse and rider galloping over a square in Rotterdam, where the position and camera work are operated so that the horse seems to turn around its axis while the environment rotates at a different tempo. Mobility, these Dutch artists convey, is often not what it seems to be.
Off-grid Mobilities
Authors: Vannini Phillip: Taggart
Published: May 2012

Drawing from sensory ethnography, the present multimodal writing—accompanied by photography and digital video—documents and interprets the mobilities of off-grid living on Lasqueti Island, British Columbia, Canada. The data presentation focuses in particular on the embodied experience of off-grid inhabitation, highlighting the sensory and kinetic experiences and practices of everyday life in a community disconnected from the North American electrical grid and highway network. The mobilities of fuel and energy are presented in unison with ethnographic attention to the taskscape of everyday activities and movements in which off-grid islanders routinely engage. The analysis, based on Tim Ingold's non-representational theory on place, movement, and inhabitation, focuses on how the material and corporeal mobilities of off-grid life body forth a unique sense of place.
European Models, Domestic Hesitance
Authors: Moraglio Massimo
Published: May 2012

Looking beyond motorways plans, this essay focuses on the role of the Italian "road" lobby in the 1920s in shaping the national transport policy. Contractors like Puricelli were the driving forces of surface transport modernization, with visionary plans but also facing a lack of sympathy by the automobile industry. Those programs were nevertheless carried out with the strong support of the Touring Club and provincial councils. In this context, it seems that the fascist dictatorship, with its hesitance, slowed—rather than hastened—road modernization. Only in 1928, feeding off the ideas of Puricelli and others, did the Mussolini government develop a proper road renewal program. Finally, framing the Italian experience in the European contexts, it emerges that despite the extreme success of American car culture, England is depicted as a more suitable model.
Britain and "the Motorway Club
Authors:   GERMANY,   GREAT BRITAIN,   MOTORWAYS,   NATIONALISM,   TRANSPORT
Published: May 2012

This article examines British attitudes to motorway construction during the 1930s, 1940s and 1950s, stressing the importance of international events to Britain's motorway building policy. It shows that while national social, political and economic imperatives, movements, and contexts were clearly of primary importance in debates about motorway construction in Britain, these often emerged amidst discussions about road-building developments abroad, particularly in mainland Europe and North America. The article focuses on British reactions to the construction of the German National Socialist Party's Autobahnen in the 1930s, examining how the Autobahnen became embroiled in a spectacular propagandist performance of the modern German nation. Finally, the paper examines the attention paid to European and U.S. motorways in postwar Britain, as engineers, landscape architects, designers, and civil servants undertook research to help inform their plans and designs for British motorways.
Regulation of Neuronal Protein Trafficking and Translocation by SUMOylation
Authors: Berndt Anja , Wilkinson Kevin A. , Henley Jeremy M.
Published: May 2012

Post-translational modifications of proteins are essential for cell function. Covalent modification by SUMO (small ubiquitin-like modifier) plays a role in multiple cell processes, including transcriptional regulation, DNA damage repair, protein localization and trafficking. Factors affecting protein localization and trafficking are particularly crucial in neurons because of their polarization, morphological complexity and functional specialization. SUMOylation has emerged as a major mediator of intranuclear and nucleo-cytoplasmic translocations of proteins involved in critical pathways such as circadian rhythm, apoptosis and protein degradation. In addition, SUMO-regulated re-localization of extranuclear proteins is required to sustain neuronal excitability and synaptic transmission. Thus, SUMOylation is a key arbiter of neuronal viability and function. Here, we provide an overview of recent advances in our understanding of regulation of neuronal protein localization and translocation by SUMO and highlight exciting areas of ongoing research.
Detection of Cardiac Biomarkers Using Single Polyaniline Nanowire-Based Conductometric Biosensors
Authors: Lee Innam , Luo Xiliang , Huang Jiyong , Cui Xinyan Tracy , Yun Minhee
Published: May 2012

The detection of myoglobin (Myo), cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and b-type natriuretic peptide (BNP) plays a vital role in diagnosing cardiovascular diseases. Here we present single site-specific polyaniline (PANI) nanowire biosensors that can detect cardiac biomarkers such as Myo, cTnI, CK-MB, and BNP with ultra-high sensitivity and good specificity. Using single PANI nanowire-based biosensors integrated with microfluidic channels, very low concentrations of Myo (100 pg/mL), cTnI (250 fg/mL), CK-MB (150 fg/mL), and BNP (50 fg/mL) were detected. The single PANI nanowire-based biosensors displayed linear sensing profiles for concentrations ranging from hundreds (fg/mL) to tens (ng/mL). In addition, devices showed a fast (few minutes) response satisfying respective reference conditions for Myo, cTnI, CK-MB, and BNP diagnosis of heart failure and for determining the stage of the disease. This single PANI nanowire-based biosensor demonstrated superior biosensing reliability with the feasibility of label free detection and improved processing cost efficiency due to good biocompatibility of PANI to monoclonal antibodies (mAbs). Therefore, this development of single PANI nanowire-based biosensors can be applied to other biosensors for cancer or other diseases.
Synthesis, Structure and Solid State Properties of Cyclohexanemethylamine Substituted Phenalenyl Based Molecular Conductor
Authors: Bag Pradip , Itkis Mikhail E. , Pal Sushanta K. , Bekyarova Elena , Donnadieu Bruno , Haddon Robert C.
Published: May 2012

We report the preparation, crystallization and solid state characterization of a cyclohexanemethylamine substituted spirobiphenalenyl radical; in the solid state the compound is iso-structural with its dehydro-analog (benzylamine-substitued compound), and the molecules packed in a one-dimensional fashion that we refer to as a π-step stack. Neighboring molecules in the stack interact via the overlap of one pair of active (spin bearing) carbon atoms per phenalenyl unit. The magnetic susceptibility measurement indicates that in the solid state the radical remains paramagnetic and the fraction of Curie spins is 0.75 per molecule. We use the analytical form of the Bonner-Fisher model for the S = 1/2 antiferromagnetic Heisenberg chain of isotropically interacting spins with intrachain spin coupling constant J = 6.3 cm−1, to fit the experimentally observed paramagnetism [χp (T)] in the temperature range 4–330 K. The measured room temperature conductivity (σRT = 2.4 × 10–3 S/cm) is comparable with that of the iso-structural benzyl radical, even though the calculated band dispersions are smaller than that of the unsaturated analog.
Antifungal Activities of New Coumarins
Authors: Al-Amiery Ahmed A. , Kadhum Abdul Amir Hassan , Mohamad Abu Bakar
Published: May 2012

Newly synthesized coumarins 4-((5-mercapto-4-phenyl-4H-1,2,4-triazol-3-yl)-methoxy)-2H-chromen-2-one and 4-((5-(phenylamino)-1,3,4-thiadiazol-2-yl)-methoxy)-2H-chromen-2-one were tested against selected types of fungi and showed significant activities. DFT calculations of the synthesized coumarins were performed using molecular structures with optimized geometries. Molecular orbital calculations provide a detailed description of the orbitals, including spatial characteristics, nodal patterns, and the contributions of individual atoms.
Anticancer Properties and Phenolic Contents of Sequentially Prepared Extracts from Different Parts of Selected Medicinal Plants Indigenous to Malaysia
Authors: Ismail Maznah , Bagalkotkar Gururaj , Iqbal Shahid , Adamu Hadiza Altine
Published: May 2012

Different parts of four edible medicinal plants (Casearia capitellata, Baccaurea motleyana, Phyllanthus pulcher and Strobilanthus crispus), indigenous to Malaysia, were extracted in different solvents, sequentially. The obtained 28 extracts were evaluated for their in vitro anticancer properties, using the MTS assay, on four human cancer cell lines: colon (HT-29), breast (MCF-7), prostate (DU-145) and lung (H460) cancers. The best anticancer activity was observed for the ethyl acetate (EA) extract of Casearia capitellata leaves on MCF-7 cell lines with IC50 2.0 μg/mL and its methanolic (MeOH) extract showed an outstanding activity against lung cancer cell lines. Dichloromethane (DCM) extract of Phyllanthus pulcher aerial parts showed the highest anticancer activity against DU-145 cell lines, while significant activity was exhibited by DCM extract of Phyllanthus pulcher roots on colon cancer cell lines with IC50 value of 8.1 μg/mL. Total phenolic content (TPC) ranged over 1–40 mg gallic acid equivalents (GAE)/g. For all the samples, highest yields of phenolics were obtained for MeOH extracts. Among all the extracts analyzed, the MeOH extracts of Strobilanthus crispus leaves exhibited the highest TPC than other samples (p < 0.05). This study shows that the nature of phenol determines its anticaner activity and not the number of phenols present.
Protective Effects of Extracts and Flavonoids Isolated from Scutia buxifolia Reissek against Chromosome Damage in Human Lymphocytes Exposed to Hydrogen Peroxide
Authors: Boligon Aline Augusti , Sagrillo Michele Rorato , Machado Luiz Filipe , De Souza Filho Olmiro , Machado Michel Mansur , Da Cruz Ivana Beatrice Manica , Athayde Margareth Linde
Published: May 2012

Flavonoids are claimed to protect against cardiovascular disease, certain forms of cancer and ageing, possibly by preventing initial DNA damage. Therefore, we investigated the protective effects of crude extract, ethyl acetate fraction and flavonoids (quercetin, quercitrin, isoquercitrin and rutin) isolated from the leaves from Scutia buxifolia against chromosome damage induced by H2O2 in human lymphocytes by analyzing cellular growth rate, cell viability, mitotic index and chromosomal instability. We found a differential response among the compounds tested, with the ethyl acetate fraction being more effective than the crude extract, a difference perhaps related to the presence of the antioxidants identified and quantified by HPLC/DAD. In general, quercetin, isoquercitrin and rutin recovered the mitotic index and chromosomal instability more than quercitrin after treatment with hydrogen peroxide.
Synthesis of Well-Defined, Water-Soluble Hyperbranched Polyamides by Chain-Growth Condensation Polymerization of AB2 Monomer
Authors: Ohta Yoshihiro , Kamijyo Yusuke , Yokoyama Akihiro , Yokozawa Tsutomu
Published: May 2012

Condensation polymerization of 5-aminoisophthalic acid methyl ester 1 bearing a N-tri(ethylene glycol) methyl ester (TEG) chain as an AB2 monomer was conducted and the properties of the resulting hyperbranched polyamides (HBPA) were investigated. When the polymerization of 1 was carried out with N-methyl core initiator 2b at various feed ratios of 1 to 2b ([1]0/[2b]0) in the presence of LiHMDS and LiCl at −10 °C, the Mn values of the obtained HBPA increased in proportion to the [1]0/[2b]0 ratio from 7 to 46 (Mn = 3810–18600), retaining a narrow molecular weight distribution (Mw/Mn = 1.11–1.19). The HBPA was soluble in water, and a 0.25 wt.−% aqueous solution of the HBPA exhibited a lower critical solution temperature (LCST). The cloud point was 21–23 °C, which is about 30 °C lower than that of the corresponding poly(m-benzamide) with the N-TEG unit.
Haunted Encounters: Exile and Holocaust Literature in German and Austrian Post-war Culture
Authors: Lang Birgit
Published: May 2012

In an essay titled ‘The Exiled Tongue’ (2002), Nobel Prize winner Imre Kertész develops a genealogy of Holocaust and émigré writing, in which the German language plays an important, albeit contradictory, role. While the German language signified intellectual independence and freedom of self-definition (against one’s roots) for Kertész before the Holocaust, he notes (based on his engagement with fellow writer Jean Améry) that writing in German created severe difficulties in the post-war era. Using the examples of Hilde Spiel and Friedrich Torberg, this article explores this notion and asks how the loss of language experienced by Holocaust survivors impacted on these two Austrian-Jewish writers. The article argues that, while the works of Spiel and Torberg are haunted by the Shoah, the two writers do not write in the post-Auschwitz language that Kertész delineates in his essays, but are instead shaped by the exile experience of both writers. At the same time though, Kertész’ concept seems to be haunted by exile, as his reception of Jean Améry’s works, which form the basis of his linguistic genealogies, shows an inability to integrate the experience of exile.
Design of Compensation Coils for EMI Suppression in Magnetostrictive Linear Position Sensors
Authors: Zhang Yongjie , Liu Weiwen , Yang Jinfeng , Lv Chunfeng , Zhao Hui
Published: May 2012

This paper presents recent development on magnetostrictive linear position sensors (MLPS). A new compensation coil structure improves the EMI suppression and accuracy considerably. Furthermore, experimental results indicate that the new structure can improve the accuracy to ±0.13 mm nearly double the ±0.2 mm obtained with traditional structures. As another design continuation after the differential waveguide structure, this new structure is a practical and reliable implementation technique for the commercialization of MLPS.
Integral T-Shaped Phantom-Dosimeter System to Measure Transverse and Longitudinal Dose Distributions Simultaneously for Stereotactic Radiosurgery Dosimetry
Authors: Yoo Wook Jae , Moon Jinsoo , Jang Kyoung Won , Han Ki-Tek , Shin Sang Hun , Jeon Dayeong , Park Jang-Yeon , Park Byung Gi , Lee Bongsoo
Published: May 2012

A T-shaped fiber-optic phantom-dosimeter system was developed using square scintillating optical fibers, a lens system, and a CMOS image camera. Images of scintillating light were used to simultaneously measure the transverse and longitudinal distributions of absorbed dose of a 6 MV photon beam with field sizes of 1 × 1 and 3 × 3 cm2. Each optical fiber has a very small sensitive volume and the sensitive material is water equivalent. This allows the measurements of cross-beam profile as well as the percentage depth dose of small field sizes. In the case of transverse dose distribution, the measured beam profiles were gradually become uneven and the beam edge had a gentle slope with increasing depth of the PMMA phantom. In addition, the maximum dose values of longitudinal dose distribution for 6 MV photon beam with field sizes of 1 × 1 and 3 × 3 cm2 were found to be at a depth of approximately 15 mm and the percentage depth dose of both field sizes were nearly in agreement at the skin dose level. Based on the results of this study, it is anticipated that an all-in-one phantom-dosimeter can be developed to accurately measure beam profiles and dose distribution in a small irradiation fields prior to carrying out stereotactic radiosurgery.
Healthcare-associated infections among pediatric oncology patients in Pakistan: risk factors and outcome
Authors: Siddiqui Naveed- ur-Rehman , Wali Rabia , Haque Anwar- ul , Fadoo Zehra
Published: May 2012

Introduction: Pediatric oncology patients are at increased risk of contracting healthcare-associated infections (HAIs), which are responsible for increased morbidity and mortality rates as well as treatment costs.  This study aimed to identify the frequency of HAIs among pediatric oncology patients and their outcome. Methodology: Pediatric oncology patients admitted between January 2009 and June 2010 in a pediatric ward at Aga Khan University Hospital, Karachi, Pakistan, who developed HAIs, were analyzed. Results: A total of 90 HAIs were identified in 32 patients in 70 admissions. The HAI rate among pediatric oncology patients was 3.1/100 admission episodes. Bloodstream infections (63 episodes, 90.0%) were the most common, followed by urinary tract infection (two episodes, 2.9%). Gram-positive infections were seen in 54 (60%) patients, followed by Gram-negative infection in 34 (37.8%), and fungi in 2 (2.8%) cases. Coagulase negative staphylococci was the most common Gram-positive and Escherichia coli and Pseudomonas aeruginosa were most common Gram-negative infections. Mortality rate among pediatric oncology patients who developed HAIs was 12.5% (4/32). Total parental nutrition use and length of stay longer than 30 days were the identified risk factors associated with increased mortality among pediatric oncology patients who developed HAIs. Conclusion: We report an HAI rate among pediatric oncology patients of 3.1/100 admission episodes with a mortality rate of 12.5% in Pakistan. Further studies should be done, especially in the developing world, to identify the risk factors associated with increased mortality among pediatric oncology patients so that adequate measures can be taken to reduce the mortality among these patients.
Comparison of four serological assays for the diagnosis of Chlamydia trachomatis in subfertile women
Authors: Muvunyi Claude , Claeys Laurens , De Sutter Tineka , De Sutter Petra , Temmerman Marleen , Van Renterghem Lieve , Claeys Geert , Padalko Elizaveta
Published: May 2012

Introduction: Chlamydia antibody testing (CAT) in serum has been introduced as a screening method in the infertility workup. We evaluated the test characteristics of two ELISA tests compared to micro-immunofluorescence tests (MIFs).  MIFs are considered the gold standard in the C. trachomatis IgG antibodies detection. We also compared the accuracy of all CAT tests in predicting tubal subfertility, using laparoscopy as a reference. Methodology: Four commercial serological methods were used to analyse 101 serum samples for the presence of C. trachomatis IgG antibodies from patients at the Infertility Clinic of Ghent University Hospital. The diagnostic utility for prediction of tubal infertility of serological methods was evaluated based on patients' medical records. Results: A comparison of the serological assays showed  little difference  in the major performance characteristics: the sensitivities of all MIFs and ELISAs were 100% for all assays (except the ELISA Vircell, with a sensitivity of 90%), and the specificities ranged from 92% for MIF Ani Labsystems to 98% for the MIF Focus and ELISA Vircell. As compared to laparoscopy data, CAT positivity in subfertile women with tubal damage (n=40) did not significantly differ from that of subfertile women without tubal damage (n=61): Positive predictive values (PPV) of CAT ranged from 53% to 60% and negative predictive values (NPV) ranged from 62% to 64%.  Conclusion: evaluated ELISAs are comparable to MIFs in the detection of C. trachomatis IgG antibodies and should be preferred for large serological studies, especially in resource poor settings.
A retrospective study of community-acquired Salmonella infections in patients attending public hospitals in Lagos, Nigeria
Authors: Akinyemi Kabiru Olusegun , Oshundare Yetunde O , Oyeyinka Oladeji G , Coker Akitoye Olusegun
Published: May 2012

Introduction: A retrospective cohort study on Salmonella-associated diseases (SADs) was conducted in 14 public hospitals across Lagos State, Nigeria, between 1999 and 2008. Methodology: Medical records of clinically diagnosed patients with confirmed Salmonella infections were reviewed for the 10-year period. Laboratory diagnosis of typhoid fever cases in all the hospitals were first based on Widal agglutination tests then followed by culture, while non-typhoidal Salmonella infections were based on culture technique. Results: A total of 85,187 confirmed cases of SADs were found, of which 880 deaths were recorded (case-fatality rate = 1.03% / 10 years). The mean incidence of SADs in Lagos State for the 10-year period was estimated at 45 cases per 100,000 persons/year, while that of typhoid fever alone was 16 cases per 100,000 persons/year. During the studied period, the number of deaths due to typhoid fever was significantly (P < 0.05) higher than deaths due to gastroenteritis except in 2003 and 2004. Risk associated with typhoidal deaths was 4 to 11 times greater when compared to gastroenteritis deaths between 2000 and 2002. Salmonella-associated diseases were most prevalent in adults 21 -to30 years of age (49.49%). Cases of patients with invasive Salmonella-associated gastroenteritis were observed mainly in children under five years of age. Conclusion: The current surveillance data indicated high incidence of SADs in areas exposed to environmental contaminations. This study revealed that infections caused by Salmonella enterica serovars are endemic in our environment thus poses a serious threat to public health. Constant public health education is essential to avert undue epidemics.
The prevalence of congenital and perinatal cytomegalovirus infections among newborns of seropositive mothers
Authors: AlKhawaja Shahnaz , Ismaeel Abdulrahman , Botta Giuseppe , Senok Abiola Catherine
Published: May 2012

Introduction: This study aimed to determine the prevalence of congenital and perinatal human cytomegalovirus (HCMV) infections among newborns in two major neonatal intensive care units (NICU) in Bahrain. Methodology: One hundred newborns comprised of 84 preterm and 16 term babies admitted to the NICUs were enrolled in the study. During the first six weeks of life, urine and saliva was obtained from the babies weekly and serial breast milk samples were obtained from the mothers. Maternal serum HCMV IgG was measured. Virus isolation and detection was done by shell vial culture and nested PCR. Results: Maternal HCMV IgG-seropositivity was 100%. Eight HCMV infections were detected comprising of three congenital and five perinatal infections. Congenital HCMV infection was found in preterm (2/84; 1.9%) and term (1/16; 6.3%) babies. HCMV DNA was detected in breast milk samples obtained during the first 10 days postpartum from all mothers whose babies had congenital HCMV. Forty-nine women provided breast milk samples between four and six weeks post-partum and HCMV DNA was detected in the breast milk of 11 women. Five (45.5%) of these eleven were mothers of babies with perinatal HCMV infection. There was no significant difference in the detection of HCMV using shell vial culture versus nested PCR method. Conclusion: The findings indicate occurrence of congenital and perinatal HCMV transmission in this setting of high maternal seropositivity. The use of shell vial culture and PCR amplification for HCMV screening in the NICU for rapid detection of infection during the early postnatal period is recommended.
Tigecycline and intravenous fosfomycin zone breakpoints equivalent to the EUCAST MIC criteria for Enterobacteriaceae
Authors: Pasteran Fernando , Lucero Celeste , Rapoport Melina , Guerriero Leonor , Barreiro Irene , Albornoz Ezequiel , Veliz Omar , Corso Alejandra
Published: May 2012

Introduction: Tigecycline and intravenous (i.v.) fosfomycin could be alternative therapeutic options for the treatment of carbapenemase-possessing Enterobacteriaceae bacterial infections. However, routine laboratories are forced to test these drugs using minimum inhibitory concentration (MIC) methods as zone breakpoints are not available for the disc diffusion technique. Methodology: Clinical and Laboratory Standards Institute methods for agar dilution and disc diffusion were compared to determine tentative zone breakpoints that best correlate to tigecycline and i.v. fosfomycin MIC breakpoints defined by the European Committee on Antimicrobial Susceptibility Testing. A total of 195 Enterobacteriaceae with defined mechanisms of resistance were tested in duplicate assays. Half of the strains were characterized as carbapenemase producers (KPC-2, OXA-48, OXA-163, VIM-1, VIM-2, IMP-8, NDM-1). Results: Corresponding zone diameters of susceptible ≥15mm, resistant ≤12mm and susceptible ≥17mm, resistant ≤15mm for the 50µg fosfomycin plus 50µg glucose-6-phosphate and 200µg fosfomycin plus 50µg glucose-6-phosphate discs, respectively, allowed categorization of the strains with an acceptable level of error (< 10% minor errors, < 1.5 % major errors, < 1% very major errors and categorical agreement > 90%). For the 15µg tigecycline disc, the best performance was achieved with the corresponding zone diameters of susceptible ≥ 21mm and resistant ≤ 16mm, which eliminated the very major and major errors but not the minor errors (34.4%). Conclusions: Based on these results, tigecycline and fosfomycin can be included in the routine panel of antibiotics for susceptibility testing by disc diffusion to provide fast and reliable information for the selection of treatment alternatives, especially for strains with extreme resistance, as carbapenemase producers.
Intra- and inter-laboratory evaluation of an improved multiplex-PCR method for detection and typing of Salmonella
Authors: Martinez-Ballesteros Ilargi , Paglietti Bianca , Rementeria Aitor , Laorden Lorena , Garcia-Ricobaraza Maria , Bikandi Joseba , Rubino Salvatore , Garaizar Javier
Published: May 2012

Introduction: We developed and evaluated a multiplex-PCR method for rapid detection of the most common Salmonella serovars in both developed and developing countries. Additionally, the stability of the premixed reagents at high room temperature was studied. Methodology: Fifty-two Salmonella strains belonging to the collections of the University of Sassari, Italy, and to the University of the Basque Country, Spain, and a collection of a hundred blinded strains, were used to evaluate the multiplex-PCR. Primers targeting genes STY1599 and fliC were selected, and the method was evaluated both intra and inter-laboratories. Results: The inter-laboratory reproducibility was 95.92%, with a kappa index of 0.757 that indicates a substantial agreement and a high accuracy (80.81%). The sensitivity, specificity, accuracy and precision indexes for the Salmonella genus and S. Typhi targets were maximum, although the targets for Paratyphi A, Typhimurium and Enteritidis showed less accuracy. During a seven-week period, hot-start multiplex-PCR runs were performed with reagents mixed with wax to test their stability at 30ºC, and no significant variation in the patterns of amplification was observed. Conclusions: An improved multiplex-PCR for rapid detection of the most common serovars of Salmonella operable in both developed and developing countries has been designed and tested intra and inter-laboratories. Following a careful optimization protocol will not only allow the confirmation of any suspicious colony by the amplification of the Salmonella genus target, but also the preliminary adscription to the prevalent serovars. Premixed reagents with wax facilitate the throughput and stability of reagents at high room temperatures.
Mères, migrantes et malades en Guyane et à Saint-Martin : la maternité au croisement de rapports sociaux inégalitaires
Authors: Carde Estelle
Published: May 2012

Résumé En Guyane et à Saint-Martin, les grossesses en contexte d’infection par le VIH sont plus fréquentes qu’ailleurs en France. Elles sont le fait, dans une grande majorité des cas, de femmes immigrées. Une enquête de terrain a été menée par observations et entretiens auprès de 19 de ces femmes et de 54 professionnels impliqués dans leur suivi social et médical, afin de comprendre les enjeux sociaux qui sous-tendent leurs maternités. Pauvreté, isolement, dépendance vis-à-vis de leurs partenaires, secret sur leur maladie stigmatisée et absence de titre de séjour placent ces femmes dans des rapports sociaux inégalitaires. Ces rapports s’articulent selon des configurations diverses, non seulement évolutives au cours de ces maternités (de la conception au suivi du nouveau-né) mais aussi marquées par les spécificités spatiales de chacun des deux territoires. Pour le système de soins, le défi reste le même sur les deux terrains : atténuer les conséquences, sur la santé des femmes et de leurs enfants, de ces rapports sociaux inégalitaires.
Quel avenir pour l'élevage dans le bassin cotonnier de l'Ouest du Burkina Faso ? Dynamiques agro-pastorales et recompositions territoriales
Authors: Gonin Alexis , Tallet Bernard
Published: May 2012

Résumé La présentation des systèmes d’élevage dans l’Ouest du Burkina Faso permet de montrer la juxtaposition sur les mêmes espaces de pratiques différentes ; la remise en cause des mobilités pastorales au cours des deux dernières décennies est lourde d’incertitudes : comment repenser la mobilité des troupeaux dans un contexte de fort accroissement des espaces agricoles et de réduction des espaces pastoraux ? La vocation du bassin cotonnier est-elle uniquement agricole ou agro-pastorale ? Derrière la « mise en territoire » des espaces pastoraux se cachent des stratégies d’acteurs aux intérêts divergents. En l’absence de point d’équilibre, c’est l’issue de ces rapports de force qui décidera de la place de l’élevage dans l’économie régionale. Différents scénarios qui en découlent sont envisagés.
À la recherche des « voix » des fallāhīn dans un dossier d’archives judiciaires égyptiennes
Authors: Clément Anne
Published: May 2012

À travers l’étude du dossier de Mikhīmar, un jeune fallāh (paysan égyptien) condamné à mort pour meurtre en 1893, cet article montre qu’une approche des archives centrée sur les traces matérielles laissées par le processus de composition et de recomposition du dossier permet de restituer en partie la performance des différents acteurs du processus judiciaire, et contribue par là même à jeter une lumière nouvelle sur le système de justice colonial au tournant du xxe siècle. Plus précisément, l’analyse des traces — citations entre parenthèses et pétitions en annexes — laissées par la négociation, qui se déroule tout au long de la procédure entre la famille de la victime et les autorités judiciaires autour de la nature commanditée du meurtre et des poursuites à engager contre les responsables, révèle à la fois la dimension conflictuelle et éminemment politique du processus de décision des magistrats et une capacité d’expression et de contestation du système tout à fait insoupçonnée de la part des fallāhīn.
Archiver ailleurs, archiver autrement ?
Authors: Baumann Stefanie
Published: May 2012

La « Fondation arabe pour l’image » est un projet archivistique dont le siège est à Beyrouth, et qui est dédié à la collection de photographies du Moyen-Orient prises par des photographes arabes entre 1860 et 1960. Elle a été lancée par un groupe d’artistes en vue d’instaurer une sorte d’histoire alternative de la photographie — qui contrerait les manuels d’histoire de la photographie européens ou américains dans lesquels les représentations photographiques du monde arabe sont souvent construites à partir d’un point de vue orientaliste. La structure et le fonctionnement de ce centre d’archives suivent des logiques hétérogènes remettant en question non seulement le concept d’archive et ses pratiques institutionnelles, mais aussi l’image photographique dans différents contextes, et selon ses différentes propriétés et connotations.
Matière à controverse
Authors: Raymond Candice
Published: May 2012

Cet article a pour objet la polémique qui a opposé entre les années 1980 et 2000 Adel Ismail, historien et diplomate libanais ayant édité une vaste collection de documents diplomatiques français relatifs à l’histoire moderne du Liban, et Antoine Hokayem, historien universitaire à l’origine d’une critique virulente de ces publications et lui-même éditeur de recueils d’archives. L’analyse des différentes séquences du processus polémique vise à identifier les types de manipulation auxquels ces documents ont été soumis depuis leur collecte jusqu’à leur usage polémique et à étudier leurs modes d’articulation avec les logiques historiographiques, politiques et économiques qui en ont sous-tendu le développement. L’examen des dispositifs éditoriaux adoptés par les protagonistes de la polémique mettra en lumière leur rôle dans le déroulement de cette dernière et les effets produits par la matérialité même de ces dispositifs.