bluuebunny/crossref_metadata_2025_split huggingface dataset:
Steady‐State Pharmacokinetics and Pharmacodynamics of Meropenem in Hospitalized Patients
Authors: Cheatham S. Christian , Kays Michael B. , Smith David W. , Wack Matthew F. , Sowinski Kevin M. 
Published: May 2008

Study Objective. To evaluate the steady‐state pharmacokinetics and pharmacodynamics of meropenem 500 mg every 6, 8, and 12 hours, based on renal function, in hospitalized patients.Design. Prospective, open‐label, steady‐state pharmacokinetic study.Setting. One tertiary care medical center and one community hospital.Patients. Twenty adult patients (12 men, 8 women) with suspected or documented bacterial infections requiring antimicrobial therapy.Intervention. Patients received 30‐minute infusions of meropenem 500 mg every 6 hours (group 1), every 8 hours (group 2), or every 12 hours (group 3) based on estimated creatinine clearances greater than 60, 40–60, or 10–39 ml/minute, respectively.Measurements and Main Results. Serial blood samples were collected after 2 or more days of therapy. Meropenem concentrations were determined by high‐performance liquid chromatography, and pharmacokinetic data were analyzed by noncompartmental methods. Monte Carlo simulations (10,000 patients) were performed to calculate the cumulative fraction of response (CFR) for a percentage of the dosing interval that free drug concentrations remain above the minimum inhibitory concentration (fT>MIC) of 40% by using pharmacokinetic data for each group and MIC data for seven gram‐negative pathogens from the Meropenem Yearly Susceptibility Test Information Collection (MYSTIC, 2004–2005) database. Maximum and minimum serum concentrations (mean ± SD) were 29.2 ± 9.8 and 2.4 ±1.1 μg/ml, 33.2 ± 8.5 and 3.8 ± 2.7 μg/ml, and 33.5 ± 4.7 and 4.9 ± 1.6 μg/ml for groups 1, 2, and 3, respectively. The half‐life values were 2.5 ± 0.9, 3.4 ± 1.3, and 6.1 ± 1.4 hours, and the values for volume of distribution at steady state were 29.3 ± 8.7, 23.8 ± 8.1, and 28.7 ± 8.6 L for groups 1, 2, and 3, respectively. For all three groups, the CFR was greater than 90% for the enteric pathogens and Pseudomonas aeruginosa and 82.4–85.2% for Acinetobacter species.Conclusion. Pharmacodynamic analyses suggest that regimens of meropenem 500 mg every 6, 8, or 12 hours, adjusted for renal function, are acceptable for treatment of infections caused by enteric gram‐negative pathogens and P. aeruginosa. However, more aggressive dosing or alternative dosing strategies may be necessary for Acinetobacter species.
Pharmacodynamics of Uniform versus Nonuniform Warfarin Dosages
Authors: Hameed Mohamed S. , Nafziger Anne N. , Gartung Anne M. , Bertino Joseph S. 
Published: May 2008

Study Objective. To compare the pharmacodynamics of uniform versus nonuniform warfarin dosages.Design. Prospective, randomized, crossover study.Setting. Anticoagulation clinic.Subjects. Twenty healthy subjects who had the extensive metabolizer cytochrome P450 (CYP) genotype of 2C9*1/*1 or CYP2C9*1/*3.Intervention. Subjects received either warfarin 5.75 mg once/day (two 1‐mg tablets plus one and a half 2.5‐mg tablets) as part of the uniform dosage group or warfarin 7.5 mg/day on Mondays and Fridays and 5 mg/day on each of the remaining days of the week as part of the nonuniform dosage group. Subjects received the first regimen for 17 days, had a 2‐week washout period, and then were switched to the other regimen for another 17 days.Measurements and Main Results. During both treatment periods, international normalized ratios (INRs) were checked daily using a fingerstick method. Any changes in concomitant drug therapy, including over‐the‐counter and supplement products, as well as health status were recorded. The Scheffe post hoc test revealed no significant differences in mean INR values obtained during receipt of the two dosage regimens. In both dosage groups, variation in the INR became more pronounced as INR values increased. No adverse events (i.e., major or minor bleeding) or changes in drug therapy were reported during the study.Conclusion. Our findings suggest that it is safe to use a nonuniform dosage regimen of warfarin to reach a target INR range. With both uniform and nonuniform regimens, close monitoring remains important to ensure that patients remain within the desired INR range.
Absorption, Bioavailability, and Partner Transfer of Estradiol from a Topical Emulsion
Authors: Taylor Maida B. , Gutierrez Maria J. 
Published: May 2008

Study Objective. To investigate the systemic absorption of estradiol in partners of postmenopausal women after making skin‐to‐skin contact with the application sites of estradiol topical emulsion.Design. Open‐label, nonrandomized clinical study.Setting. Clinical study unit.Subjects. Fourteen postmenopausal women and their male partners (mean ± SD age 57.6 ± 8.7 and 49.1 ± 13.3 yrs, respectively).Intervention. Women applied 1.74 g/day of estradiol topical emulsion (containing 2.5 mg estradiol/g) to each leg on 2 consecutive days. Their male partners were exposed to the application sites by mean of vigorous skin‐to‐skin contact at 2 and 8 hours after application.Measurements and Main Results. Serum concentrations of estradiol, estrone, and estrone sulfate were measured in the female subjects and their male partners. The mean ± SD estradiol level in the women at baseline was 2.9 ± 1.5 pg/ml. Their average concentration (Caverage) increased from 15.3 ± 14.8 pg/ml on the first day of treatment to 27.6 ± 22.7 pg/ml on the second day. Among male partners, Caverage for serum estradiol increased from 17.0 ± 4.3 pg/ml at baseline to 21.0 ± 4.4 pg/ml on the second exposure day. Their geometric mean fold ratio for the area under the serum concentration‐time curve from 0–24 hours was 1.25 (baseline vs after second exposure, p<0.0001).Conclusions. Estradiol was transferred to male partners by means of vigorous skin‐to‐skin contact at application sites. Although the increase in postexposure levels of estradiol was statistically significant, all levels were still below the upper limit of the normal range for men (45 pg/ml).Conclusion
Concurrent Administration of Sirolimus and Voriconazole: A Pilot Study Assessing Safety and Approaches to Appropriate Management
Authors: Surowiec Dorothy , DePestel Daryl D. , Carver Peggy L. 
Published: May 2008

Study Objectives. To assess the use and safety of concurrent administration of voriconazole and sirolimus—which is contraindicated—and to determine approaches for appropriately managing patients who receive both drugs.Design. Retrospective medical record review.Setting. University‐affiliated medical center.Patients. Thirty‐one cases in 23 inpatients who received at least one dose of voriconazole and sirolimus concomitantly within a 24‐hour period.Measurements and Main Results. Data on sirolimus and voriconazole indications, doses, routes, frequencies, and administration times; number of days of coadministration; and sirolimus dosage adjustments were collected. In addition, data on laboratory values, adverse events, sirolimus concentrations, and concomitant drugs, including cytochrome P450 (CYP) 3A isoenzyme and P‐glycoprotein inhibitors and inducers, were collected for 7 days before, during, and for 14 days after coadministration. No cases of elevated sirolimus concentrations (> 20 mg/ml) occurred in patients stabilized with voriconazole before starting low‐dose sirolimus 0.5‐1 mg/day, or in those stabilized with sirolimus 0.5‐2 mg/day who had baseline sirolimus concentrations of 12 ng/ml or lower and whose sirolimus dose was decreased by 50% before the addition of voriconazole. In contrast, elevated sirolimus concentrations were experienced in patients receiving sirolimus doses of 4 mg/day or higher who had sirolimus concentrations of 12 ng/ml or higher and whose sirolimus dose was not decreased before addition of voriconazole. In a patient who received sirolimus with itraconazole, a strong CYP3A isoenzyme inhibitor, one case of only a minimal increase in the sirolimus concentration occurred after the addition of voriconazole.Conclusions. Sirolimus and voriconazole can be safely coadministered as long as consideration is given to which agent the patient receives first, the sirolimus dosage, sirolimus concentrations, and concurrent disease states and CYP3A isoenzyme inhibitors. Sirolimus concentrations should be closely and routinely monitored before, during, and after coadministration of voriconazole and other CYP3A isoenzyme inhibitors. Based on the results of this pilot study, a protocol on the management of this drug combination will be implemented and prospectively evaluated for efficacy and safety.
Investigation of the corrosivity of some water-glycol hydraulic fluids to stainless steel 316L for subsea applications
Authors: Zheng Lei , Neville Anne 
Published: May 2008

Abstract
Water-glycol solutions (HFC) [1] are one of the most commonly used hydraulic fluids in applications where fire hazard is a concern such as in the offshore oil industry. However they may cause corrosion failures of components in electro-hydraulic control systems that can have serious consequences for the operation of an entire subsea oil recovery system. The principal objective of this study is to assess the corrosion behaviour of the main material of construction used for the components in such systems (Stainless Steel 316L) in a range of commercial water-glycol hydraulic fluids (Oceanic HW443, HW525, HW540, HT, EE1), and to find out the probable factors that may affect the corrosivity of each fluid.
The corrosivity of each fluid was ranked according to the breakdown potential obtained from cyclic potentiodynamic polarization (CPP) tests [2]. Gas chromatography-mass spectroscopy (GC-MS) analysis was carried out to assess the components of the different organic additives in each fluid and the water percentage of each fluid was determined by Karl Fischer titration. A comparison of relative ethylene glycol content has indicated that the higher the concentration of ethylene glycol the more corrosive the fluid is to stainless steel 316L if the additive package is the same. However, additive packages dominate the corrosivity.
Erosion-corrosion of pipeline steel X65 and 22Cr duplex stainless steel in CO2 saturated environment
Authors: HU Xinming , Neville Anne 
Published: May 2008

Abstract
An erosion-corrosion study on pipeline material degradation in sand-containing and CO2 saturated environments has been carried out. The total material loss, corrosion, erosion and their interactions (often referred to as synergy) have been assessed for pipeline steel X65 and 22Cr duplex stainless steel in various environmental conditions (temperature, flow velocity and sand content). The experimental results show the 22Cr duplex stainless steel exhibits a better performance under liquid-solid impingement for all conditions resulting from the better resistance to corrosion related degradation. A comparison between the experimental data and the empirical prediction model developed in this work shows a good correlation.
Study of the Effect of Inhibitor on Erosion-Corrosion in CO2-Saturated Condition With Sand
Authors: Neville A. , Wang C. 
Published: May 2008

Abstract
CO2 corrosion inhibitors are widely adopted in production and processing facilities in the oil and gas industry. The challenge is that under multiphase flow (liquid/sand) and high shear stress conditions, successful application of inhibitors can be difficult. Under such severe erosion-corrosion conditions, the total material damage is identified as being associated with electrochemical corrosion, solid particle erosion and synergistic effects between the two.
To investigate the possibility of using corrosion inhibitors to reduce erosion-corrosion, this study has characterized the corrosion phenomena occurring at the carbon steel-electrolyte interface under erosion-corrosion conditions. AC impedance was used to provide mechanistic information of corrosion with absence and presence of a commercial corrosion inhibitor in erosion-corrosion conditions in a CO2-saturated brine. Experiments were conducted using a Rotating Cylinder Electrode cell containing sand at different temperatures, rotational speeds and with various inhibitor concentrations. Four commercial inhibitors have been investigated.
In this work the potential for applying corrosion inhibitors for the reduction of material loss in erosion –corrosion is assessed and the role of the inhibitor in reducing corrosion, erosion and interactive mass loss mechanisms is discussed.
Inhibition Performance of a New Series of Mono/Diamine-Based Corrosion Inhibitors for HCl Acid Solutions
Authors: Al-Taq Ali A. , Ali Shaikh A. , Nasr-El-Din Hisham A 
Published: May 2008

Abstract
New monoamine and diamine compounds were synthesized from dodecylamine and 1, 12-dodacanediamine, and evaluated as acid corrosion inhibitors for low-carbon steel. The inhibition behavior of these compounds was examined using gravimetric and electrochemical methods (linear polarization and Tafel plot). Weight loss tests were conducted in 1M HCl at 140°F for six hours. To simulate acid stimulation treatments, other weight loss tests were conducted using typical acid stimulation concentrations 4.1 and 7.7 M HCl, (equivalent to 15 and 28 wt%, respectively) at 140°F for two hours. The effects of corrosion inhibitor type and concentration, and acid concentration were investigated.
Experimental results indicated that examined monoamine compounds exhibited better corrosion inhibition for low-carbon steel in 1 M HCl acid solution than their corresponding diamine compounds. This behavior was clearly observed at a low corrosion inhibitor concentration of 50 ppm. Tafel Plot results suggest that the inhibition mechanism for all examined compounds involved a simple reaction site blocking. For both monoamine and diamine compounds, the inhibition performance was found to increase with increasing corrosion inhibitor concentration and decrease with acid concentration.
Aromatic and multiple bonds substituents introduced to monoamine and dimamine compounds were found to enhance inhibition performance compared to the starting materials (dodecylamine and 1, 12-dodacanediamine). This is attributed to the π-electrons present in aromatic and multiple bonds substituents. Both dodecylamine derivatives with a triple bond or an aromatic substituent exhibited excellent protection in 4.1 M HCl. However, the derivative with a triple bond showed the best protection (98%) at 7.7 M HCl. This result is very promising and suggests that this corrosion inhibitor has a good potential to be used as a corrosion inhibitor in oil/gas wells acid stimulation treatments.
Hydrothermal Chemistry of Formate Brines and Its Impact on Corrosion in HPHT Wells
Authors: Howard S. K. , Downs J. D. 
Published: May 2008

Abstract
Formate brines have been successfully used in hundreds of HPHT drilling and completion operations over the past 12 years and have exhibited remarkable thermal stability. This has been confirmed by analyses of brines recovered from extreme HPHT wells after lengthy exposure (months/years). Laboratory testing cited in the literature has, however, indicated that significant formate brine decomposition to bicarbonate and hydrogen gas should occur at even relatively low temperatures if the brine is in contact with catalytic surfaces. The potential damage that such decomposition and the evolution of decomposition products could cause to metallic materials has caused concern in the industry.
The inconsistency between laboratory and field behavior has indicated that standard laboratory autoclaves are not suited for reproducing or simulating downhole conditions. Typical differences between these two environments are pressure, presence of gas cap, and amount and type of catalytic surfaces. In order to better simulate actual downhole conditions, experiments have been carried out in specialist equipment developed to examine hydrothermal chemistry. A non-catalytic gold test cell was used for the decomposition testing, immersed in a high pressure high temperature autoclave filled with water.
The flexibility of the gold cell has allowed experiments to be conducted and sampled at high pressure without the presence of an artificial gas cap. Initial tests have shown that any decomposition reactions taking place in formate brine under hydrothermal conditions will reach equilibrium with bicarbonate. This discovery has also given us useful information on how to formulate bicarbonate-rich formate brine compositions which remain stable even at very high temperatures. As bicarbonate is an important component in buffered formate brines, these formulations are not much different from the current brines already in field use.
Analyses of a range of formate brine samples that have been recovered from two HPHT wells have confirmed that formate reaches equilibrium with bicarbonate over time under hydrothermal conditions.
This paper reviews what has been learnt about formate decomposition under realistic hydrothermal conditions, and exposes new information on how the equilibrium reactions might impact on metal integrity and corrosion processes in HPHT wells.
The most important lesson learned from testing in the flexible gold cell is that traditional laboratory autoclaves operated with a gaseous head space are not suited for testing formate brines at high temperatures. In fact, test results generated in such autoclaves will be laboratory artifacts that do not simulate or reproduce what actually happens in HPHT wells.
Increasing the Life of Flare Tips
Authors: Fox A. B. , Huang Yan Yan , Rafik Dena , Williamson J. , Lindley T. C. , Lee P. D. 
Published: May 2008

Abstract
Flare tips are essential for safety. Maintenance is difficult and costly. Flare tips are subjected to high combustion temperatures, thermal cycling, oxidation and marine corrosion. Following a number of flare tip failures an in depth study by Imperial College was carried out into the failure of a flare tip from a UK platform, looking for service life improvement. Materials selection and design solutions were considered. The study considered alternative materials and concluded that materials selection was the smaller part of the answer; design changes can double service life. This study used failure investigation, high temperature experimental and thermo-mechanical modelling analysis.
The modelling process simulated two common flaring conditions and correctly predicted the observed failure of initiation and crack propagation from holes used to bolt on flame stabilizing plates to the top of the flare. The calculated thermal stress and strains enabled the low cycle fatigue life and minimum creep life to be predicted. It was concluded that service life could be improved by replacing Incoloy alloy 800HT (UNS N08800) with Inconel alloy 625 (UNS N06625), an alloy with attractive mechanical properties and improved high temperature corrosion resistance. Repositioning or eliminating bolt holes can double service life.
The Role of Packer Fluids in the Annular Environmentally Assisted Cracking of CRA Production Tubing
Authors: McKennis J. S. , Termine Enrico J. , Bae N. S. , Kimura M. , Shimamoto K. , Sato H. 
Published: May 2008

Abstract
The increased use of corrosion resistant alloys (CRAs) in deep HPHT wells has led to production-tubing cracking failures throughout the industry. Many of these failures have occurred from the outside (annulus side) and been attributed to Environmentally Assisted Cracking (EAC) and hence, best described as Annular EAC (AEAC). Examination of these failures points to a serious incompatibility of the production tubing metallurgy with the packer fluid under stress.
To solve this problem, combined expertise in fluid chemistry and metallurgy is needed. Consequently, in 2003 a research alliance of the co-authors to examine the compatibility of a wide spectrum of completion fluids with various martensitic stainless steel metallurgies was established.
This unique research collaboration leading to extensive stress cracking testing performed with different metallurgies and different fluids under simulated well conditions has resulted in an extensive database and new body of knowledge regarding the causes behind AEAC failures. With respect to the mechanisms of failure, a variety of contaminants in completion/packer fluids have been found to play a dominant role. Such contaminants include sulfur-containing species, oxidants, and select ionic species. This paper addresses the impact of the new information and identifies serious misconceptions regarding the role of completion & packer fluids in the tubular failures.
The information accrued from this comprehensive study has advanced the industry's knowledge of the causes of AEAC by detailing the previously unrecognized importance of various contaminants present in the fluids. Importantly, it has led to the recognition of the need for quality assurance and best-practice fluid management throughout the life cycle of the fluids. The extensive database and a user friendly software program derived from it permit minimization of tubular failure risk by matching packer fluids with metallurgies under a wide variety of stipulated well conditions.
Cathodic protection system life assessment
Authors: Buxton D C , John D G 
Published: May 2008

Abstract
The North Sea environment is a harsh environment and cathodic protection is typically applied to offshore steel platforms to control degradation by corrosion. As offshore platforms near the end of their design life, the cathodic protection systems, either galvanic anodes or impressed current systems, may also be reaching the end of their life. Where the platform life is extended, it is necessary to consider whether the existing cathodic protection systems are fit-for-purpose for the intended life extension period.
Over the past few years the condition of a hybrid cathodic protection system, which comprises both galvanic anodes and seabed impressed current anodes, on one North Sea platform has been investigated and assessed. This has included regular performance assessment, specific assessment of anode wastage and estimates of remaining life. The aim of the assessment was to predict when extensive retrofit activity might be required, thus avoiding unnecessary corrosion degradation and enabling any retrofit work to be scheduled in advance.
Modeling processes can be used in the cathodic protection life assessment to provide a better understanding of the existing protection system and to predict future performance.
The assessment has demonstrated that the platform is satisfactorily protected from corrosion and that extensive retrofit work is not expected to be required in the short term.