bluuebunny/crossref_metadata_2025_split huggingface dataset:
COMPARATIVE STUDY ON THE INTENSITY OF Mycobacterium leprae EXPOSURE BETWEEN HOUSEHOLD AND NONHOUSEHOLD CONTACT OF LEPROSY
Authors: Arsyad Yuniarti , Jifanti Friska , Amiruddin Muhammad Dali , Anwar Anis Irawan , Adriaty Dinar , Wahyuni Ratna , Iswahyudi Iswahyudi , Agusni Indropo 
Published: March 2017

Leprosy stills a public health problem in West Sulawesi which has a Case Detection Rate (CDR) around 43.69/100.000 population. Household contacts of leprosy are a high risk group to be infected, due to droplet infection mode of transmission of the disease. A nose swab examination and serological study was conducted to detect exposure of M. leprae of people who live in leprosy endemic area. Detection of M. leprae in the nasal cavity will represent the exposure rate from outside and the measurement of specific antibody is represented the result of exposure to the immune system. Two group of inhabitants (30 household contacts of leprosy and 30 nonhousehold contacts) were involved in the study. They live in Banggae district, a leprosy endemic area of Majene Regency, West Sulawesi. Sixty nose swab samples and sixty capillary blood samples from the same invidividuals of the two groups were collected and sent to Leprosy laboratory of the Institute of Tropical Disease, Airlangga University Surabaya. A Polymerase Chain Reaction (PCR) was performed to the nose swab samples for detection of M. leprae. The blood samples were examined serologically to measure the level of anti PGL-1 antibody. PCR examination of nose swab samples showed 1/30 positive result in the household contact group and also 1/30 positive result in non-household contact of leprosy (statistically no significant difference, p > 0.05). Serological study showed higher sero-positive result in the household contact group (15/30 or 50%) compared to non-household contact (11/30 or 36%), but statistical calculation revealed no significant difference between the two groups (p > 0.05) on sero-positive results of leprosy. It is concluded that household and non-household contact in leprosy have the same risk to be affected by the disease. The term of household and non-household contact need to be redefined. The possible role of exposure from the environment was also discussed, especially from non-human resource of M. leprae.
MYCOBACTERIA AND OTHER ACID FAST ORGANISMS ASSOCIATED WITH PULMONARY DISEASE IN JOS, NIGERIA PULMONARY DISEASE AND ACID FAST ORGANISMS
Authors: AE Ani , B Diarra , UR Dahle , C Lekuk , F Yetunde , AM Somboro , Tounkara Anatole , J Idoko 
Published: March 2017

Objective: Acid fast bacilli (AFB) for sputum smear microscopy is the affordable method used for prompt diagnosis of tuberculosis in Nigeria despite its lack of specificity and limited sensitivity. The study aims to identify Mycobacterium tuberculosis and other acid fast organisms isolated from sputum of of HIV positive adult patients with pulmonary disease in Jos, Nigeria. Methods: Acid fast organisms isolated from 80 AFB positive sputa of HIV positive adult patients suspected for tuberculosis in Jos, Nigeria were identified for members of M. tuberculosis Complex (M tuberculosis, M bovis, M africanum, M canetti M. microti and M. caprae) by use of spoligootyping, Multiplex Gen Probe, Hain genotype assay and gene sequencing for spoligotype negative isolates. Results: Seven different spoligotypes of M. tuberculosis complex were identified from 70/80 (87.5%) total number of isolates. M. kansasii (1), M. dulvalii (1) Nocardia species (1) and Tsukamurella species (2) were detected from 5/10 spoligotype negative isolates. Conclusion and Recommendation: Although M. tuberculosis is the dominant AFB associated with chronic pulmonary disease in Jos, Nigeria, other clinically relevant mycobacteria were observed in the study. This suggests that other AFB positive microorganisms associated withtuberculosis -like symptoms could be misdiagnosed and incorrectly treated as M. tuberculosis. It is therefore necessary for laboratories in TB high burden countries to step up diagnostic procedures beyond routine smear microscopy.
The Relation of Obesity and Individual Factors with Knee Osteoarthritis
Authors: Anggraini Niken Enestasia , Hendrati Lucia Yovita 
Published: March 2017

ABSTRACTOsteoarthritis represent disease at most found in the world, including in Indonesia. This disease cause pain in bone and disability at patient so disturb everyday activity. One of removed occurrence of knee Osteoarthritis was obesity. Other factors like age, gender, physical activity, and habit smoke were risk factors of knee Osteoarthritis . This research was the relationship of obesitas and individuals factors with occurrence knee osteoarthritis at Surabaya Islamic Hospital. The methods of this research was an observation with case control design. Level of sampel was 64 which consist of 32 case group and 32 control group from incomed patient to radiology unit Islamic Hospital Surabaya for X-Ray photo. The dependent variable was occurence of knee osteoarthritis . The independent variables were obesity, gender, age, physical activity, habit smoke. The instrument used was a questionnaire and form BMI measurement. Data analysis used Chi-Square test with α=0,05 and to know oods ratio (OR) used statclac. The results showed significant relationship between occurence of knee osteoartritis with obesity (p=0,001,OR=7,20), age (p=0,012,OR=3,67) , gender (p=0,005,OR=4,69). For the characteristic of habit smoke (p=0,268,OR=0,56) and physical activity (p=0.919,OR=0,71) were’nt associated with occurence of knee Osteoarthritis at Surabaya Islamic Hospital. The conclusion there is relationship between obesity with knee osteoarthritis at Surabaya Islamic Hospital. Risk factor knee osteoarthritis like gender and age also there were relation with occurence of knee osteoarthritis , for the risk factor of physical activity and habit smoke were’nt relation with occurence of knee osteoarthritis. Keyword : Knee osteoarthritis, obesity, individual factors
Novel Studies on Precipitated Phosphate Ester Scale Inhibitors for Precipitation Squeeze Application
Authors: Valiakhmetova A. , Sorbie K. S. , Jordan M. M. , Boak L. S. 
Published: March 2017

Abstract
Often, scale inhibitors (SIs) applied in oilfields are organic phosphorus compounds, either phosphonates, phosphorus containing polymers, or phosphate esters. The latter group of SIs, phosphate esters, have not been as extensively studied as the others and we focus on these in this paper. The current work is focused on the properties of precipitated calcium - phosphate ester (PE) complexes denoted as PE_Can, with the stoichiometry n.
SIs, injected into a wellbore during squeeze treatments, can be retained in the formation rock via two main mechanisms, adsorption and precipitation. Precipitation squeeze treatments are often based on the reaction between a SI and divalent cations where the mixed complexes that form, denoted SI_Mn2+, usually havea much lower solubility than the free SI itself.
In this work we show, that the phosphate ester precipitation process is quite different from that of SIs commonly used by industry, i.e.phosphonates and polymers. Unlike phosphonate-divalent complexes, the phosphate ester complexes stoichiometry is not sensitive to solution pH. However, it is found that elevated pH of PE/Ca solutions positively affects the activity of the precipitates which form; the higher the precipitation pH, the higher the inhibition efficiency (IE, to barite) of the resulting precipitate. The higher IE was determined for stock, precipitated and then re-dissolved phosphate ester and its supernatant solution. These IE results show that phosphate ester activity is very sensitive to temperature; the IE of all phosphate ester solutions decreases with increasing temperature. This phenomenon probably occurs due to hydrolysis reactions at the higher temperatures which changes the chemistry of the phosphate ester solutions. To check this assumption, Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR) were applied to monitor structural changes occurring in molecules of precipitated and stock phosphate ester solutions.
The results obtained in this work are of practical significance for the effective design of phosphate ester precipitation squeeze treatments, since these products offer (i) a more environmentally acceptable alternative to phosphonates, and (ii) a chemical that is significantly easier to detect within produced brine than many polymers used by the industry, many of which are phosphorus free polymers. However, PE scale inhibitors application environment is at lower temperatures, &lt;80°C, relative to phosphonates which can fuctionup to 150°C, and polymers over 200°C.
Effect of Nitrate on Carbon Steel Corrosion
Authors: Vargas Silvia M. , Woollam Richard , Durnie William , Hodges Michael , Betancourt Daniel 
Published: March 2017

Abstract
Nitrate has been used to control Sulphate Reducing Bacteria (SRB) in oil and gas reservoirs. Nitrate is thermodynamically a strong oxidizer, which could increase carbon steel corrosion rates yet; literature documenting the effect of nitrate on corrosion is scarce and contradictory.
This study investigated the effect of nitrate on carbon steel corrosion under simulated oilfield produced water (rich in carbon dioxide with pH~5) and simulated seawater (minimum carbon dioxide and a pH~7). CO2 corrosion tests were conducted with carbon steel X65 exposed to uninhibited brines at 25°C, 60°C, and 80°C via rotating cylinder electrode (RCE). Inhibited synthetic brine was tested under acidic environments at 80°C. Changes in nitrate, nitrite, ammonium and ferrous ions were monitored using ion chromatography.
The results provide experimental evidence to demonstrate that the corrosivity of nitrate strongly depends on pH. Nitrate tends to increase CO2 corrosion rates in the presence of synthetic produced brine (pH~5) and is relatively benign when added to synthetic seawater (pH~7). At the conditions tested, nitrite impurities contained within the source of nitrate tend to increase carbon steel corrosion exposed to synthetic brines.
In the presence of metallic iron and under CO2 environments, nitrate reduces to ammonium, which is thermodynamically stable in acid solutions. The reduction of nitrate can be modelled based on first order kinetics. The main factors promoting the reduction of nitrate are pH, iron to nitrate ratio, and temperature.
A Microfludic Technique for the Evaluation of Demulsifiers
Authors: Loufakis D. N. , Schmitt A. K. , Nelson C. , Hoyles S. , Goodwin J. , White B. , Ayers C. 
Published: March 2017

Abstract
Crude oil is usually produced from the ground in a form of an oil-and-water emulsion. Prior to the treatment of crude oil in the refineries, the removal of water is necessary to prevent corrosion in the pipeline and the refinery equipment. Chemical agents and heat are the most common methods used in order to break the emulsion and enhance the separation of oil and water. The selection of the appropriate chemical (also known as demulsifier or emulsion breaker) is performed by an old, but well-accepted method in the oil industry, the "bottle test". Even though it is widely used, this procedure may be very tedious and time consuming. A typical set of bottle tests may include the testing of several hundred samples. This is partially due to the inability to preselect a promising set of demulsifiers, due to the variability of crude emulsions. As a result, the identification of new methods for fast evaluation of demulsifier performance is highly desirable.
During this study, the microfluidic platform was explored in an effort to identify a novel, fast, and accurate technique for the evaluation of crude oil demulsifiers. An X-junction microfluidic channel was used to generate water droplets in dry crude oil in a controlled manner. The addition of demulsifying agents in the oil phase resulted in the generation of droplets of varying size, and droplet coalescence downstream in the device. In an effort to better understand the microfluidic responses, and their relationship to the macroscopic performance of demulsifiers, these results were examined and compared against bottle test data of the crude oil/water emulsion. A strong correlation among the water drop and oil dryness performance (bottle test response) and the droplet coalescence and relative standard deviation of droplet size (microfluidic response) was observed. This study proves that the microfluidic platform has the potential to serve as an alternate and fast method for demulsifier screening.
Development of Structure-Property Relationships for Oilfield Water Clarifiers
Authors: Young Kaylie L. , D'Ottaviano Fabio , Rhodes Lisa , Gao Wei , Young Wen-Shiue , Behles Jacqueline A. , Khan Greg 
Published: March 2017

Abstract
The production chemical industry currently lacks a comprehensive fundamental understanding of how polymeric oilfield water clarifiers work at the molecular level and which polymer components are most important for increasing field performance. The existing method for choosing a water clarifier involves a brute force approach, bottle testing as many products as possible, and includes a significant amount of trial and error. The study herein describes an approach in which a statistical library of acrylic polymers was used to develop a predictive model of performance for clarifiers in an Alkaline Surfactant Polymer (ASP) flooded reservoir in order to develop a customized polymer.
A library of 50 acrylic polymers was synthesized and characterized with Asymmetric Flow Field Flow Fractionation (A4F). The polymers were evaluated for performance in three wells in an ASP flooded field by measuring the oil and grease remaining in the produced water after treatment. A three-step approach was taken to extract structure-property relationships. Principle Component Analysis was employed to reduce the dimensionality of the characterization properties. The principle components were then modeled using the polymer recipes in JMP/SAS. Finally, a model was developed to understand the field performance results in terms of the principle components.
In the ASP Flood, the performance model indicated that the molecular weight of the acrylic polymers was the most important parameter for water clarifier performance in the three wells tested. The three evaluated wells showed significant variation in sensitivity to molecular weight, which emphasizes the importance of testing polymers in a representative sample of the wells within a reservoir when choosing a product. Importantly, our method of measuring residual oil and grease levels after treatment to evaluate performance was found to have a strong correlation with the ranking system employed by the field bottle testers. This study is one of the first examples of the determination of quantitative structure-property relationships for polymeric oilfield water clarifiers. By using this approach, one can identify the most important parameters for performance in a given field. Using the resulting predictive model, a customized water clarifier can be built for the field to give optimal performance.
Investigation of Oil Adhesion to Shale Rocks for EOR
Authors: Nguyen D. , Phan T. , Phan J. , Hsu T. P. 
Published: March 2017

Abstract
Significant work is ongoing within the industry to determine a best practice for maximizing oil recovery from fractured oil-wet shale reservoirs. Rapid decline curves are often observed and water flooding can be largely ineffective because of negative capillary pressure. The goal of this work is to identify a chemical solution that can maximize oil and gas recovery in unconventional reservoirs by reduction of hydrocarbon adhesion to shale rocks. In order to evaluate an optimal solution, numerous formulations were developed and tested for their impact on adsorption and adhesion on rock and/or sand, changes in interfacial tension, and how the formulation affects the wettability of the formation. Shale rocks were characterized for their surface energy, as this governs the adsorption and adhesion tension of crude oil, water, and chemicals to the solid surface. Formulations were selected that minimized the adsorption on rock and sand surfaces since such adsorption may lead to an increase in the surface tension of fluid pumped into the well and the interfacial tension between the crude oil and fluid. Contact angle measurements were used to determine the Van der Waals and Lewis acid-base components of surface energies for Barnett, Eagle Ford, Niobrara, and Bakken shales. In addition, contact angle measurements and interfacial tension were used to determine the adhesion of crude oil to the rock. Numerous chemical formulations were evaluated to identify products that can decrease the work of adhesion, making oil recovery more efficient (i.e. less work is required to remove oil drops from the rock surface and mobilize them). Competitive adsorption of formulations at the oil-water and rock-water interface was evaluated. The amount of natural surfactants in the oil and their adsorption on the rocks (reversible vs. irreversible) affect whether the rock is oil-wet or water-wet. If the adsorption is reversible, the rock would be more water-wet, resulting in higher oil recovery. Formulations which altered the wettability to water wet rapidly, but reduced the interfacial tension slightly, exhibited the highest oil recoveries.
Based on wettability alteration, interfacial tension, and work of adhesion, a novel product was developed that is salt tolerant (in 30% TDS), thermally stable (115°C), and produces high oil recovery (i.e., 60% OOIP). Kinetics were also improved compared to conventional treatments and brine alone. In addition, this product showed a low static adsorption on the Bakken shale (0.20 mg product active/gram rock) and no emulsion tendency.
Optimization of Scale Treatment Program of a CO2 Water-Alternating-Gas System for Enhanced Oil and Gas Production
Authors: Lu Haiping , Stewart Preston , Jones Doug , Penkala Joe , Brooks Johnathon 
Published: March 2017

Abstract
The use of a water-alternating-gas (WAG) system for enhanced oil and gas production can introduce challenges from scaling issues. At a CO2-WAG facility in the western Rockies of the USA, scale solids were observed to accumulate in the produced fluid gathering and water injection systems. In addition to carbonate scales, suspended solids such as formation fines, corrosion products and bacteria were typically present in the production and injection waters. Although scale inhibitor applications are the preferred approach to prevent scale formation, the suspended solids can limit the performance or availability of these inhibitors by providing large surface areas for their adsorption.
To investigate the effects of pre-existing solids in diminishing performance of scale inhibitors, three types of solids, CaCO3, Fe2O3 and FeS were used in static bottle tests to mimic the impact on scale inhibitor performance in the operating system. A variety of scale inhibitor chemistries were screened, including various types of phosphonate-based and polymer-based scale inhibitors. Test bottles containing simulated field brine were spiked with 100, 1,000 or 10,000 mg/L of each solid and dosed with different scale inhibitors at various concentrations. Results showed that a decrease in scale inhibitor efficiency accompanies increasing amounts of added solids. With CaCO3 and Fe2O3 solids, equivalent amounts of solids limited scale inhibitor performance comparably. FeS solids had the greatest adverse impacts on scale inhibitor performance, possibly because of FeS oxidation or stronger adsorption of scale inhibitors onto FeS oxidation products. In the final phase of this study, scale inhibitor applications were conducted in the CO2 WAG system. Optimization was achieved based on monitoring and system performance. These applications are carefully documented and presented to provide a perspective for effective management of scale in WAG systems.
In conclusion, laboratory results on scale inhibitor performance in the presence of pre-existing solids provided insight into the influence of suspended solids on the efficacy of the scale treatment mechanism. It also established a guideline for inhibitor dosages during field applications to successfully manage scale in this CO2 WAG system in the western Rockies.
Microemulsion Phase Behavior Model Using Empirical Trends in Chemical Potentials
Authors: Torrealba V. A. , Johns R. T. 
Published: March 2017

Abstract
Surfactant-based enhanced oil recovery methods have been a promising technique for the last several decades due to the surfactant's ability to mobilize previously trapped oil by significantly reducing capillary forces at the pore-scale. However, the field-implementation of these techniques have been challenged by the high cost of chemicals, which makes the margin of error for the deployment of such methods increasingly narrow. Some commonly recognized issues are surfactant adsorption, surfactant partitioning to the excess phases, thermal and physical degradation, and scale-representative phase behavior.
Recent contributions to the petroleum engineering literature have used the hydrophilic-lipophilic difference net-average curvature (HLD-NAC) model to develop a phase behavior EoS to fit experimental data and predict phase behavior away from tuned data. The model currently assumes spherical micelles, which may yield errors in the bicontinuous region where micelles transition into cylindrical and planar shapes.
In this paper, we introduce a new empirical phase behavior model based on chemical potentials and HLD that eliminates NAC so that spherical micelles are no longer assumed. The model is able to describe physical two-phase regions, and is shown to represent accurately experimental data at fixed composition and changing HLD (e.g. a salinity scan) as well as compositional data at fixed HLD. Further, the model is extended to account for surfactant partitioning into the excess phases. The model is benchmarked against experimental data, showing excellent fits for a wide variety of experiments, and is compared to the HLD-NAC EoS model for reference.