To determine whether differences exist in visual acuity and corneal thickness after phacoemulsifi... more To determine whether differences exist in visual acuity and corneal thickness after phacoemulsification using various viscoelastic substances. Phillips Eye Institute, Minneapolis, Minnesota, USA. Fifty patients having routine phacoemulsification cataract extraction and intraocular lens implantation by a single surgeon using the same technique were randomly assigned to receive intraoperative administration of 1 of 3 viscoelastic substances: Amvisc Plus(R) (sodium hyaluronate 1.6%), OcuCoat(R) (hydroxypropyl methylcellulose 2%), or Viscoat(R) (chondroitin sulfate 4%-sodium hyaluronate 3%). Visual acuity and corneal thickness on the first postoperative day were compared between groups. Patients with a best corrected visual acuity (BCVA) of 20/40 or better 1 day postoperatively had significantly thinner corneas (596 microm) than those with a BCVA worse than 20/40 (639 microm). There were no differences in postoperative BCVA or percentage increase in central corneal pachymetry among the 3 viscoelastic groups. Viscoat, Amvisc Plus, and OcuCoat were comparable in their ability to produce clear corneas and good vision after routine phacoemulsification.
RESEARCH DESIGN AND METHODS A total of eight centers with population-based childhood-onset diab... more RESEARCH DESIGN AND METHODS A total of eight centers with population-based childhood-onset diabetes registers developed according to the standards of EURODIAB ACE (Aetiol-ogy of Childhood Onset Diabetes on an Epidemiological Basis) (18) part icipated ...
The aim of this study was to investigate the impact of obesity on diastolic function in children ... more The aim of this study was to investigate the impact of obesity on diastolic function in children and adolescents. Echocardiographic measurements were compared in 28 obese subjects (14 males, 14 females) and 15 age- and gender-matched lean controls (8 males, 7 females). Two-dimensional ultrasound imaging, M-mode imaging, and pulse-wave conventional and tissue Doppler measurements were used to assess cardiac structure and function at rest. No differences were evident between lean and obese subjects in age (13.3 +/- 0.5 vs 12.4 +/- 0.4 years), height (163 +/- 4 vs 159 +/- 2 cm), or systolic blood pressure (119 +/- 3 vs 123 +/- 2 mm Hg). Body mass (54.6 +/- 4.0 vs 85.8 +/- 3.6 kg, p < 0.0001) and body mass index (20.5 +/- 0.7 vs 33.3 +/- 1.0 kg/m2, p < 0.00001) were significantly greater in the obese subjects, whereas measurements of wall thickness (interventricular septal wall 0.86 +/- 0.04 vs 0.89 +/- 0.02 cm, posterior wall 0.83 +/- 0.04 vs 0.91 +/- 0.02 cm) and fractional shortening (38.6 +/- 1.2% vs 38.8 +/- 1.2%) did not significantly differ. The E/E' ratio (6.86 +/- 0.20 vs 8.30 +/- 0.32, p…
Edad de Oro Cantabrigense: Actas del VII Congreso de la Asociación Internacional del Siglo de Oro (AISO). Anthony Close, ed. Madrid: Iberoamericana Editorial Vervuert, 2006
The objective is to assess patient preferences for attributes associated with third agent HIV med... more The objective is to assess patient preferences for attributes associated with third agent HIV medications, including fosamprenavir/ritonavir (FPVr), fosamprenavir (FPV), lopinavir/ritonavir (LPVr), atazanavir (ATZ), and efavirenz (EFV). Subjects with HIV were recruited in the US and Germany to complete a computerized adaptive conjoint survey that assessed 13 attributes, including moderate to severe side effects, regimen convenience, drug resistance and efficacy. Literature on the target third-agent HIV drugs was used to identify percentage risk and severity level descriptions for each attribute. The derived preference (utility) weights for each attribute level informed the calculation of relative importance estimates for each attribute and the desirability of combinations of attributes matching the respective target third agents. The analysis included 288 HIV-positive participants (US: 132; Germany: 156), 205 of whom were treatment-experienced and 83 of whom were treatment-naïve. Of the 13 medication attributes evaluated, developing drug resistance, the risk of lipodystrophy, the risk of gastronitestinal side effects (diarrhoea, nausea and vomiting) and regimen convenience had the greatest impact on preferences. The profile based on FPVr was most preferred. Differences in the risk of developing drug resistance, risk of lipodystrophy, risk of gastrointestinal side effects and regimen convenience would likely be most influential in the perceived relative value of a third-agent medication. Physicians may wish to consider these features, especially when discussing HIV treatment options with their patients.
Research on HIV medication adherence has relied mainly on quantitative methods. The objective of ... more Research on HIV medication adherence has relied mainly on quantitative methods. The objective of this study was to explore factors associated with adherence from the HIV-infected patient's perspective. Six focus groups were convened with treatment-experienced HIV-positive individuals. The discussions focused on issues that make it easy or difficult to adhere to HIV regimens. Thirty-five patients participated in the focus groups, which were conducted in Washington, D.C., and Los Angeles. The mean age was 48; 66% were male; 63% were black; and 40% contracted HIV through heterosexual contact. Six major themes emerged from the data that influenced adherence to medication: regimen complexity/medication features (including number of pills), lifestyle fit, emotional impacts (including worry, anger, stress and anxiety), side effects, medication effectiveness, and communication (including information from friends, physicians, and published sources). The data informed a conceptual framework, illustrating the possible interactions among these themes that can potentially be used by clinicians when discussing HIV treatment options with patients. This is potentially one of the first focus group studies concentrating on HIV medication adherence. The findings highlight specific factors that should be considered when trying to improve adherence and may be helpful in clinical decision-making.
To provide a comparative evaluation of psychometric properties for three or more HIV disease-spec... more To provide a comparative evaluation of psychometric properties for three or more HIV disease-specific quality-of-life (QoL) instruments. Four instruments were selected using the following criteria: multiple publiations of instrument, focus of instrument on QoL, psychometric validation publication or comparison with prevoiusly validated questionnaire, stages of HIV/AIDS used or evaluated in the study, and inclusion of sample items or the instrument in at least one publication. The four HIV-specific QoL instruments were: HIV/AIDS-Targeted Quality of Life Instrument, Medical Outcomes Study HIV questionnaire (MOS-HIV), Functional Assessment of Human Immunodeficiency Virus Infection, and HIV Overview of Problems -- Evaluation System. These instruments were evaluated using combined criteria derived from McHorney and Tarlov and Shumaker et al. The criteria include: administration, content, depth, reliability, validity, and responsiveness. A letter grade scale (A,B,C,D) was used in rating the criteria. No instrument demonstrated ideal psychometric properties. The MOS-HIV questionnaire was the only instrument that published results for seven of the eight categories. Therefore, a decision cannot be made about the best instrument to use for measuring QoL in an HIV-positive patient. Published data for these questionnaires had common limitations of sample size, study design, and population demograhpics, Hence, further testing of these questionnaires is recommended before use in any study to determine suitability, reliability and validity.
The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between ... more The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between tubulin dimers within the microtubule lattice. Although its microtubule severing activity is likely important for fundamental processes including mitosis and axonal outgrowth, its mechanism of action is poorly understood. To better understand this activity, an in vitro assay was developed to enable the real-time observation of katanin-mediated severing of individual, mechanically unconstrained microtubules. To interpret the experimental observations, a number of theoretical models were developed and compared quantitatively to the experimental data via Monte Carlo simulation. Models that assumed that katanin acts on a uniform microtubule lattice were incompatible with the in vitro data, whereas a model that assumed that katanin acts preferentially on spatially infrequent microtubule lattice defects was found to correctly predict the experimentally observed breaking rates, number and spatial frequency of severing events, final levels of severing, and sensitivity to katanin concentration over the range 6-300 nM. As a result of our analysis, we propose that defects in the microtubule lattice, which are known to exist but previously not known to have any biological function, serve as sites for katanin activity.
Association for Science Teacher Education, St. Louis, MO, 2008
Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementa... more Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementary and middle school classrooms. Teachers typically have limited knowledge of models and modeling or of students' ideas about models and modeling. Yet engaging in scientific modeling in the classroom places a high demand on teachers, and they typically do not have access to highquality modeling-oriented curriculum materials. The MoDeLS project works to design innovative and effective supports for teachers' learning around ...
Journal of Research in Science Teaching, Aug 1, 2009
Modeling is a core practice in science and a central part of scientific literacy. We present theo... more Modeling is a core practice in science and a central part of scientific literacy. We present theoretical and empirical motivation for a learning progression for scientific modeling that aims to make the practice accessible and meaningful for learners. We define scientific modeling as including the elements of the practice (constructing, using, evaluating, and revising scientific models) and the metaknowledge that guides and motivates the practice (eg, understanding the nature and purpose of models). Our learning progression ...
To determine whether differences exist in visual acuity and corneal thickness after phacoemulsifi... more To determine whether differences exist in visual acuity and corneal thickness after phacoemulsification using various viscoelastic substances. Phillips Eye Institute, Minneapolis, Minnesota, USA. Fifty patients having routine phacoemulsification cataract extraction and intraocular lens implantation by a single surgeon using the same technique were randomly assigned to receive intraoperative administration of 1 of 3 viscoelastic substances: Amvisc Plus(R) (sodium hyaluronate 1.6%), OcuCoat(R) (hydroxypropyl methylcellulose 2%), or Viscoat(R) (chondroitin sulfate 4%-sodium hyaluronate 3%). Visual acuity and corneal thickness on the first postoperative day were compared between groups. Patients with a best corrected visual acuity (BCVA) of 20/40 or better 1 day postoperatively had significantly thinner corneas (596 microm) than those with a BCVA worse than 20/40 (639 microm). There were no differences in postoperative BCVA or percentage increase in central corneal pachymetry among the 3 viscoelastic groups. Viscoat, Amvisc Plus, and OcuCoat were comparable in their ability to produce clear corneas and good vision after routine phacoemulsification.
RESEARCH DESIGN AND METHODS A total of eight centers with population-based childhood-onset diab... more RESEARCH DESIGN AND METHODS A total of eight centers with population-based childhood-onset diabetes registers developed according to the standards of EURODIAB ACE (Aetiol-ogy of Childhood Onset Diabetes on an Epidemiological Basis) (18) part icipated ...
The aim of this study was to investigate the impact of obesity on diastolic function in children ... more The aim of this study was to investigate the impact of obesity on diastolic function in children and adolescents. Echocardiographic measurements were compared in 28 obese subjects (14 males, 14 females) and 15 age- and gender-matched lean controls (8 males, 7 females). Two-dimensional ultrasound imaging, M-mode imaging, and pulse-wave conventional and tissue Doppler measurements were used to assess cardiac structure and function at rest. No differences were evident between lean and obese subjects in age (13.3 +/- 0.5 vs 12.4 +/- 0.4 years), height (163 +/- 4 vs 159 +/- 2 cm), or systolic blood pressure (119 +/- 3 vs 123 +/- 2 mm Hg). Body mass (54.6 +/- 4.0 vs 85.8 +/- 3.6 kg, p < 0.0001) and body mass index (20.5 +/- 0.7 vs 33.3 +/- 1.0 kg/m2, p < 0.00001) were significantly greater in the obese subjects, whereas measurements of wall thickness (interventricular septal wall 0.86 +/- 0.04 vs 0.89 +/- 0.02 cm, posterior wall 0.83 +/- 0.04 vs 0.91 +/- 0.02 cm) and fractional shortening (38.6 +/- 1.2% vs 38.8 +/- 1.2%) did not significantly differ. The E/E' ratio (6.86 +/- 0.20 vs 8.30 +/- 0.32, p…
Edad de Oro Cantabrigense: Actas del VII Congreso de la Asociación Internacional del Siglo de Oro (AISO). Anthony Close, ed. Madrid: Iberoamericana Editorial Vervuert, 2006
The objective is to assess patient preferences for attributes associated with third agent HIV med... more The objective is to assess patient preferences for attributes associated with third agent HIV medications, including fosamprenavir/ritonavir (FPVr), fosamprenavir (FPV), lopinavir/ritonavir (LPVr), atazanavir (ATZ), and efavirenz (EFV). Subjects with HIV were recruited in the US and Germany to complete a computerized adaptive conjoint survey that assessed 13 attributes, including moderate to severe side effects, regimen convenience, drug resistance and efficacy. Literature on the target third-agent HIV drugs was used to identify percentage risk and severity level descriptions for each attribute. The derived preference (utility) weights for each attribute level informed the calculation of relative importance estimates for each attribute and the desirability of combinations of attributes matching the respective target third agents. The analysis included 288 HIV-positive participants (US: 132; Germany: 156), 205 of whom were treatment-experienced and 83 of whom were treatment-naïve. Of the 13 medication attributes evaluated, developing drug resistance, the risk of lipodystrophy, the risk of gastronitestinal side effects (diarrhoea, nausea and vomiting) and regimen convenience had the greatest impact on preferences. The profile based on FPVr was most preferred. Differences in the risk of developing drug resistance, risk of lipodystrophy, risk of gastrointestinal side effects and regimen convenience would likely be most influential in the perceived relative value of a third-agent medication. Physicians may wish to consider these features, especially when discussing HIV treatment options with their patients.
Research on HIV medication adherence has relied mainly on quantitative methods. The objective of ... more Research on HIV medication adherence has relied mainly on quantitative methods. The objective of this study was to explore factors associated with adherence from the HIV-infected patient's perspective. Six focus groups were convened with treatment-experienced HIV-positive individuals. The discussions focused on issues that make it easy or difficult to adhere to HIV regimens. Thirty-five patients participated in the focus groups, which were conducted in Washington, D.C., and Los Angeles. The mean age was 48; 66% were male; 63% were black; and 40% contracted HIV through heterosexual contact. Six major themes emerged from the data that influenced adherence to medication: regimen complexity/medication features (including number of pills), lifestyle fit, emotional impacts (including worry, anger, stress and anxiety), side effects, medication effectiveness, and communication (including information from friends, physicians, and published sources). The data informed a conceptual framework, illustrating the possible interactions among these themes that can potentially be used by clinicians when discussing HIV treatment options with patients. This is potentially one of the first focus group studies concentrating on HIV medication adherence. The findings highlight specific factors that should be considered when trying to improve adherence and may be helpful in clinical decision-making.
To provide a comparative evaluation of psychometric properties for three or more HIV disease-spec... more To provide a comparative evaluation of psychometric properties for three or more HIV disease-specific quality-of-life (QoL) instruments. Four instruments were selected using the following criteria: multiple publiations of instrument, focus of instrument on QoL, psychometric validation publication or comparison with prevoiusly validated questionnaire, stages of HIV/AIDS used or evaluated in the study, and inclusion of sample items or the instrument in at least one publication. The four HIV-specific QoL instruments were: HIV/AIDS-Targeted Quality of Life Instrument, Medical Outcomes Study HIV questionnaire (MOS-HIV), Functional Assessment of Human Immunodeficiency Virus Infection, and HIV Overview of Problems -- Evaluation System. These instruments were evaluated using combined criteria derived from McHorney and Tarlov and Shumaker et al. The criteria include: administration, content, depth, reliability, validity, and responsiveness. A letter grade scale (A,B,C,D) was used in rating the criteria. No instrument demonstrated ideal psychometric properties. The MOS-HIV questionnaire was the only instrument that published results for seven of the eight categories. Therefore, a decision cannot be made about the best instrument to use for measuring QoL in an HIV-positive patient. Published data for these questionnaires had common limitations of sample size, study design, and population demograhpics, Hence, further testing of these questionnaires is recommended before use in any study to determine suitability, reliability and validity.
The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between ... more The microtubule-severing enzyme katanin uses ATP hydrolysis to disrupt noncovalent bonds between tubulin dimers within the microtubule lattice. Although its microtubule severing activity is likely important for fundamental processes including mitosis and axonal outgrowth, its mechanism of action is poorly understood. To better understand this activity, an in vitro assay was developed to enable the real-time observation of katanin-mediated severing of individual, mechanically unconstrained microtubules. To interpret the experimental observations, a number of theoretical models were developed and compared quantitatively to the experimental data via Monte Carlo simulation. Models that assumed that katanin acts on a uniform microtubule lattice were incompatible with the in vitro data, whereas a model that assumed that katanin acts preferentially on spatially infrequent microtubule lattice defects was found to correctly predict the experimentally observed breaking rates, number and spatial frequency of severing events, final levels of severing, and sensitivity to katanin concentration over the range 6-300 nM. As a result of our analysis, we propose that defects in the microtubule lattice, which are known to exist but previously not known to have any biological function, serve as sites for katanin activity.
Association for Science Teacher Education, St. Louis, MO, 2008
Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementa... more Scientific modeling is a crucial scientific practice, yet it is rarely incorporated into elementary and middle school classrooms. Teachers typically have limited knowledge of models and modeling or of students' ideas about models and modeling. Yet engaging in scientific modeling in the classroom places a high demand on teachers, and they typically do not have access to highquality modeling-oriented curriculum materials. The MoDeLS project works to design innovative and effective supports for teachers' learning around ...
Journal of Research in Science Teaching, Aug 1, 2009
Modeling is a core practice in science and a central part of scientific literacy. We present theo... more Modeling is a core practice in science and a central part of scientific literacy. We present theoretical and empirical motivation for a learning progression for scientific modeling that aims to make the practice accessible and meaningful for learners. We define scientific modeling as including the elements of the practice (constructing, using, evaluating, and revising scientific models) and the metaknowledge that guides and motivates the practice (eg, understanding the nature and purpose of models). Our learning progression ...
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Papers by Elizabeth Davis