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Extending the stability of intravenous ampicillinHanan, Nathan January 2012 (has links)
Class of 2012 Abstract / Specific Aims: To assess the chemical stability of ampicillin for injection in normal saline at pH values ranging from 5 to 6.
Methods: A stability-indicating high performance liquid chromatography (HPLC) method was developed and used to determine the stability of ampicillin for injection in normal saline following buffering with sodium acetate and acid adjustment with HCl at pH values of 5, 5.5, and 6. To confirm that the assay was stability-indicating, ampicillin trihydrate reference standard (1 mg/mL) was exposed to alkali, acid, and oxidative stress conditions and analyzed by HPLC for the presence of degradation products. Analysis was performed on a reverse-phase (C-18) column with a mobile phase consisting of water, acetonitrile, 1 M monobasic potassium phosphate, and 1 N acetic acid (909:80:10:1). Other HPLC parameters were: flow rate 1 mL/min; detection wavelength 254 nm; injection volume 20 μL; column temperature 30 ̊C. The method was evaluated for linearity, precision, and accuracy. The chemical stability of ampicillin for injection (18 mg/mL) in normal saline and sodium acetate (pH adjusted at values of 5, 5.5, and 6) was assessed at baseline (t=0), 7, 11, 17, 31, and 44 hours and compared to a control solution (no pH adjustment). Measurements at each time interval were performed in triplicate.
Main Results: Ampicillin trihydrate reference standard (1 mg/mL) was adequately separated from degradation products following exposure to alkali, acid, and oxidative stress conditions. After 16 hours, a precipitate was observed in the solution at pH 6, and therefore stability is not reported. All other solutions (pH 5, pH 5.5, and control) were stable for at least 24 hours at room temperature and yielded t90 values of 110, 64.2, and 27.5 hours, respectively.
Conclusions: Adjustment of intravenous ampicillin solutions to pH values of 5 or 5.5 significantly increased stability. Ampicillin appears to be most stable at a pH near its isoelectric point (pH 5).
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Stability of Midazolam Intravenous Injection Solutions Under Varying Conditions and in Different Intravenous BagsEarhart, Zachary January 2009 (has links)
Class of 2009 Abstract / OBJECTIVES: The purpose of this study was to examine solutions of midazolam at a concentration of 1 mg/ml in 2 different types of IV bags while being stored under different conditions to see if they maintain stability over a one month period.
METHODS: Triplicate solutions of midazolam 1 mg/ml were made in polyolefin and polyvinyl chloride IV bags and stored under refrigeration, exposed to light at room temperature, and protected from light in amber bags at room temperature. High performance liquid chromatography was used to evaluate solution stability over a 4 week period.
RESULTS: All solutions remained stable with no statistically significant (p = 0.164) change in concentration from initial over the four week period. Storage condition also did not have an impact on stability and neither did type of plasticizer used.
CONCLUSIONS: Solutions remain stable for longer than the manufacturer stated 24 hours and may be made in advance and stored for future use.
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Synthesis, Stability, and Reactions of DichloroketeneLiddel, Harold Glenn 06 1900 (has links)
The primary objective of this work was to prepare dichloroketene.
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A Study to Determine the Relationship Between Emotional Stability and Academic AccomplishmentLatham, William Robert 06 1900 (has links)
This study is concerned with the determination of the relationship that exists between levels of emotional stability and academic accomplishment among students of Business Administration at North Texas State College. It is the hypothesis of this study that a positive relationship exists between levels of emotional stability and academic achievement among students of Business Administration at North Texas State College and that the degree of this relationship can be determined.
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Preparation of Pyridinium and Diaminocarbonium Barbituric Acid YlidesDouelle, Frederic 07 August 2003 (has links)
Through NMR experiments of the reaction of barbituric acid with carbodiimide, a general synthetic procedure for the preparation of 5-diaminomethylenebarbiturates (DABA) was developed. This procedure is very simple and applicable to the preparation of large quantities of DABA derivatives. Through the X-ray structural study of one of the DABA derivatives it was established that these compounds have a ylide-type structure with strong charge separation inside the molecule. 5-Ylide-pyridinium-methyl barbituric acid derivatives were investigated with the isolation of 4-dimethylamino-1-(2,4,6-trioxohexahydro- pyrimidin-5-ylide-methyl)-pyridinium as well as its corresponding 1,3- dimethylbarbituric acid derivative with quantitative yields. An alternative approach was attempted in order to prepare chiral 5-ylide-pyridinium-methyl-barbituric acid derivatives thus containing a chiral center between the charge separation. The extreme instability of the derivatives under investigation afforded the unique isolation of 4-dimethylamino-1- [(1,3-dimethyl-2,4,6-trioxo-hexahydro-pyrimidin-5-yl)-phenyl-methyl]-pyridinium in quantitative yield.
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Synthesis of Cyclo and Backbone Extended NucleosidesLi, Yiran January 2013 (has links)
Thesis advisor: Larry W. McLaughlin / Nucleic acids are essential biological molecules that encode and transfer genetic information from generation to generation. Intensive efforts have been made by scientists to study the properties of nucleic acids, looking for opportunities that could help diagnose, prevent, and cure disease, and/or gain a greater insight into the wonder of nature. Chapter 2 presents our synthetic attempts towards the rigidified nucleosides 2'-deoxy-6,3'-propanouridine and 2'-deoxy-6,3'-butanouridine. These nucleosides are constrained so that they mimic the native conformation in DNA duplex and are postulated to increase duplex stability, as well as increase the affinity of the nucleobase for its complementary partner. Chapter 3 presents work towards the synthesis of backbone extended nucleosides. These molecules have the potential to form a new type of helical structure when incorporated into a double helix. Through the investigation of these novel nucleic acids, we would like to gain a greater understanding of the properties that contribute to duplex stability. / Thesis (MS) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.
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Relationship Stability in Lesbian Couples with Children : a Qualitative Psychological StudyO'Rourke, Julie January 1996 (has links)
Thesis advisor: Bernard O'Brien / This study investigated factors which influenced the stability of long-term relationships among twelve lesbian couples who had been together for at least fifteen years and reared children. A retrospective, semi-structured interview was used and each participant was interviewed separately. Themes related to relationship stability were identified prior to the interview and operationalized through the interview questions. / Thesis (PhD) — Boston College, 1996. / Submitted to: Boston College. School of Education. / Discipline: Counseling, Developmental Psychology, and Research Methods.
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A fuzzy constraint satisfaction approach to achieving stability in dynamic constraint satisfaction problems.January 2001 (has links)
by Wong, Yin Pong Anthony. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 101-107). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Constraint Satisfaction Problems --- p.2 / Chapter 1.2 --- Solution Stability in Dynamic Constraint Satisfaction Problems --- p.3 / Chapter 1.3 --- Motivation of the Research --- p.5 / Chapter 1.4 --- Overview of the Thesis --- p.5 / Chapter 2 --- Related Work --- p.7 / Chapter 2.1 --- Complete Search Algorithms --- p.7 / Chapter 2.1.1 --- DnAC-4 --- p.8 / Chapter 2.1.2 --- ac --- p.9 / Chapter 2.1.3 --- DnAC-6 --- p.9 / Chapter 2.2 --- Algorithms for Stability --- p.10 / Chapter 2.2.1 --- Bellicha --- p.10 / Chapter 2.2.2 --- Dynamic Dynamic Backtracking --- p.11 / Chapter 2.2.3 --- Wallace and Freuder --- p.12 / Chapter 2.2.4 --- Unimodular Probing --- p.13 / Chapter 2.2.5 --- Train Rescheduling --- p.14 / Chapter 2.3 --- Constrained Optimization Algorithms --- p.14 / Chapter 2.3.1 --- Guided Local Search --- p.14 / Chapter 2.3.2 --- Anytime CSA with Iterative Deepening --- p.15 / Chapter 2.4 --- A Real-life Application --- p.16 / Chapter 3 --- Background --- p.17 / Chapter 3.1 --- Fuzzy Constraint Satisfaction Problems --- p.17 / Chapter 3.2 --- Fuzzy GENET --- p.19 / Chapter 3.2.1 --- Network Architecture --- p.19 / Chapter 3.2.2 --- Convergence Procedure --- p.21 / Chapter 3.3 --- Deficiency in Fuzzy GENET --- p.24 / Chapter 3.4 --- Rectification of Fuzzy GENET --- p.26 / Chapter 4 --- Using Fuzzy GENET for Solving Stability Problems --- p.30 / Chapter 4.1 --- Modelling Stability Problems as FCSPs --- p.30 / Chapter 4.2 --- Extending Fuzzy GENET for Solving Stability Problems --- p.36 / Chapter 4.3 --- Experiments --- p.38 / Chapter 4.3.1 --- Dynamic CSP Generation --- p.39 / Chapter 4.3.2 --- Problems Using Hamming Distance Function --- p.41 / Chapter 4.3.2.1 --- Variation in Number of Variables --- p.42 / Chapter 4.3.2.2 --- Variation in Domain Size --- p.45 / Chapter 4.3.2.3 --- Variation in Density and Tightness --- p.47 / Chapter 4.3.3 --- Comparison in Using Different Thresholds --- p.47 / Chapter 4.3.4 --- Problems Using Manhattan Distance Function --- p.50 / Chapter 5 --- Enhancement of the Modelling Scheme --- p.56 / Chapter 5.1 --- Distance Bound --- p.56 / Chapter 5.2 --- Enhancement of Convergence Procedure --- p.57 / Chapter 5.3 --- Comparison with Optimal Solutions --- p.60 / Chapter 5.4 --- Comparison with Fuzzy GENET(dcsp) --- p.64 / Chapter 5.4.1 --- Medium-sized Problems --- p.64 / Chapter 5.4.2 --- The 150-10-15-15 Problem --- p.67 / Chapter 5.4.3 --- Variation in Density and Tightness --- p.73 / Chapter 5.4.4 --- Variation in Domain Size --- p.76 / Chapter 5.5 --- Analysis of Fuzzy GENET(dcsp2) --- p.94 / Chapter 6 --- Conclusion --- p.98 / Chapter 6.1 --- Contributions --- p.98 / Chapter 6.2 --- Future Work --- p.99 / Bibliography --- p.101
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The Effect of Machining Residual Stresses on the Dimensional Stability of Aluminum Alloys used in Optical SystemsSpence, Timothy 12 April 2010 (has links)
Dimensional stability of materials is of critical importance in the fabrication of precision components used for applications such as optical systems. One source of dimensional instability is residual stress produced on the surfaces of parts due to machining operations. A creep model is proposed in this research that describes how these stressed layers affect the overall geometry of a component as they creep over time and temperature. Depth corrected XRD stress measurements and a bimetallic strip model were utilized to quantify the residual stress layer of two machining operations. The creep model parameters were determined by monitoring curvature over time and temperature. This model can be used for two purposes, the prediction of long term storage effects on part geometry for purposes of reliability assessment, and the design of short term, moderate temperature stress relief treatments. Two alloys were investigated, aluminum 6061-T6, and aluminum 4032-0. A methodology for applying the observed creep strain to complex parts using a finite element analysis is proposed.
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The linear stability of Reissner-Nordström spacetime for small chargeGiorgi, Elena January 2019 (has links)
In this thesis we prove the linear stability to gravitational and electromagnetic perturbations of the Reissner-Nordström family of charged black holes with small charge. Solutions to the linearized Einstein-Maxwell equations around a Reissner-Nordström solution arising from regular initial data remain globally bounded on the black hole exterior and in fact decay to a linearized Kerr-Newman metric. We express the perturbations in geodesic outgoing null foliations, also known as Bondi gauge. To obtain decay of the solution, one must add a residual pure gauge solution which is proved to be itself controlled from initial data. Our results rely on decay statements for the Teukolsky system of spin +/-2 and spin +/-1 satisfied by gauge-invariant null-decomposed curvature components, obtained in earlier works. These decays are then exploited to obtain polynomial decay for all the remaining components of curvature, electromagnetic tensor and Ricci coefficients. In particular, the obtained decay is optimal in the sense that it is the one which is expected to hold in the non-linear problem.
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