Influence of ZnO nanowire array morphology on field emission characteristics.

In this work the growth and field emission properties of vertically aligned and spatially ordered and unordered ZnO nanowires are studied. Spatially ordered nanowire arrays of controlled array density are synthesized by both chemical bath deposition and vapour phase transport using an inverse nanosphere lithography technique, while spatially unordered arrays are synthesized by vapour phase transport without lithography. The field emission characteristics of arrays with 0.5, 1.0, and 1.5 µm inter-wire distances, as well as unordered arrays, are examined, revealing that, within the range of values examined, field emission properties are mainly determined by variations in nanowire height, and show no correlation with nanowire array density. Related to this, we find that a significant variation in nanowire height in an array also leads to a reduction in catastrophic damage observed on samples during field emission because arrays with highly uniform heights are found to suffer significant arcing damage. We discuss these results in light of recent computational studies of comparable nanostructure arrays and find strong qualitative agreement between our results and the computational predictions. Hence the results presented in this work should be useful in informing the design of ZnO nanowire arrays in order to optimize their field emission characteristics generally.

Unambiguous identification of the role of a single Cu atom in the ZnO structured green band.

High quality and purity single crystal ZnO samples doped with single isotopes of (63)Cu and (65)Cu, with equal concentrations of both these isotopes, and with natural Cu using a wet chemical atomic substitution reaction and anneal were studied using low temperature optical spectroscopy. Our data on the zero phonon line of the structured green band in ZnO confirm unambiguously the involvement of a single Cu atom in this defect emission. These data allow us to confirm the main features of the assignment proposed by Dingle in 1969 and to comment further on the defect structure.

Growth and field emission properties of ZnO nanostructures deposited by a novel pulsed laser ablation source on silicon substrates.

Zinc oxide (ZnO) nanostructures were produced using a novel pulsed laser ablation apparatus comprising in-situ analysis of the plume by reflection time-of-flight mass spectrometry. Various morphologies of nano and microstructures were obtained for laser wavelengths of 1064 and 355nm, and oxygen ambient pressures of 10(-6) and 10(-2)mbar, respectively. None of the produced structures exhibited a particular type of self-organisation whereas all of them showed low aspect ratios and good field emission properties. Optimum values of 5.2Vmicrom(-1) and 2060 were obtained for the turn-on field and Fowler-Nordheim enhancement factor, respectively, for deposited nano-tipped microstructures presenting a high coverage of the substrate. The experimental data showed that for a given laser wavelength, higher field enhancement factors were obtained for the samples grown at the lower pressure of 10(-6)mbar. In these conditions, the deposited materials showed distinct nanostructuring and comparison with existing data showed the corresponding ablation plumes to contain (ZnO)(n) clusters, up to n=13. This work also shows that the electronic properties of the nanostructured ZnO produced in our conditions, as determined by the oxygen concentration during deposition, have an influence on the field emission properties in addition to the nanostructure morphology.

Can health care quality indicators be transferred between countries?

OBJECTIVE: To evaluate the transferability of primary care quality indicators by comparing indicators for common clinical problems developed using the same method in the UK and the USA. METHOD: Quality indicators developed in the USA for a range of common conditions using the RAND-UCLA appropriateness method were applied to 19 common primary care conditions in the UK. The US indicators for the selected conditions were used as a starting point, but the literature reviews were updated and panels of UK primary care practitioners were convened to develop quality indicators applicable to British general practice. RESULTS: Of 174 indicators covering 18 conditions in the US set for which a direct comparison could be made, 98 (56.3%) had indicators in the UK set which were exactly or nearly equivalent. Some of the differences may have related to differences in the process of developing the indicators, but many appeared to relate to differences in clinical practice or norms of professional behaviour in the two countries. There was a small but non-significant relationship between the strength of evidence for an indicator and the probability of it appearing in both sets of indicators. CONCLUSION: There are considerable benefits in using work from other settings in developing measures of quality of care. However, indicators cannot simply be transferred directly between countries without an intermediate process to allow for variation in professional culture or clinical practice.

Keeping quality on the policy agenda.

Quality of care in the United States and elsewhere consistently fails to meet established standards. These failures subject patients to premature death and needless suffering. Yet, unlike the experience with other threats to life (tire failures or airplane rudders), public and private policymakers have been unable to maintain sufficient interest in identifying and solving problems with quality to change the way in which care is delivered. We discuss why it is hard to keep quality on the policy agenda and suggest short-term steps that are necessary if quality is to improve here and in the rest of the world.

Parent expectations for antibiotics, physician-parent communication, and satisfaction.

OBJECTIVES: To explore how parents communicate their preferences for antibiotics to their child's physician and to examine whether physicians can communicate why antibiotics are not being prescribed in a way that maintains satisfaction with the visit. DESIGN: Previsit survey of parents, audiotaping of the study encounters, and a postvisit survey of parents and physicians. SETTING: Two private pediatric practices. PARTICIPANTS: Ten physicians (response rate = 77%) and a consecutive sample of 295 eligible parents (response rate = 86%) who attended acute care visits for their children between October 1996 and March 1997. MAIN OUTCOME MEASURES: Physician-perceived pressure to prescribe antibiotics and parental visit-specific satisfaction. RESULTS: Fifty percent of parents expressed a previsit expectation for antibiotics. Among these parents, only 1% made a direct verbal request for them. Even when no direct requests for antibiotics were made, physicians still perceived an expectation for antibiotics 34% of the time. Among parents who did not receive expected antibiotics, those offered a contingency plan from the physician (i.e., the possibility of receiving antibiotics in the future if their child did not get better) had a higher mean satisfaction score than parents not receiving a contingency plan (76 vs. 58.9; P<.05). CONCLUSION: Physicians should consider providing a contingency plan to parents who expect antibiotics for their children when there is no clinical indication. Further study is needed to determine how parents indirectly communicate their desire for antibiotics and what additional communication techniques physicians can use to resist the overprescribing of antibiotics.

A new approach for measuring quality of care for women with hypertension.

BACKGROUND: Guidelines for care of hypertensive patients have proliferated recently, yet quality assessment remains difficult in the absence of well-defined measurement systems. Existing systems have not always linked process measures to blood pressure outcomes. METHODS: A quality measurement system was developed and tested on hypertensive women in a West Coast health plan. An expert panel selected clinically detailed, evidence-explicit indicators using a modified Delphi method. Thirteen indicators (1 screening, 5 diagnostic, 5 treatment, and 2 follow-up indicators) were selected by this process. Trained nurses used a laptop-based tool to abstract data from medical records for the most recent 2 years of care. RESULTS: Of 15 004 eligible patients with hypertensive and other chronic disease codes, 613 patients were sampled, all eligible for the screening indicator. Of these, 234 women with an average blood pressure of 140/90 mm Hg or more, or a documented diagnosis of hypertension, were studied for the remaining indicators. The average woman received 64% of the recommended care. Most patients did not receive adequate initial history, physical examination, or laboratory tests. Only 37% of hypertensive women with persistent elevations to more than 160/90 mm Hg had changes in therapy or lifestyle recommended. The average adherence proportion to all indicators was lower in patients with uncontrolled blood pressure (>140/90 mm Hg) than in those with controlled blood pressure (54% vs 73%; P<.001). CONCLUSIONS: Quality of hypertensive care falls short of indicators based on randomized controlled trials and national guidelines. Poor performance in essential care processes is associated with poor blood pressure control.

Health information on the Internet: accessibility, quality, and readability in English and Spanish.

CONTEXT: Despite the substantial amount of health-related information available on the Internet, little is known about the accessibility, quality, and reading grade level of that health information. OBJECTIVE: To evaluate health information on breast cancer, depression, obesity, and childhood asthma available through English- and Spanish-language search engines and Web sites. DESIGN AND SETTING: Three unique studies were performed from July 2000 through December 2000. Accessibility of 14 search engines was assessed using a structured search experiment. Quality of 25 health Web sites and content provided by 1 search engine was evaluated by 34 physicians using structured implicit review (interrater reliability >0.90). The reading grade level of text selected for structured implicit review was established using the Fry Readability Graph method. MAIN OUTCOME MEASURES: For the accessibility study, proportion of links leading to relevant content; for quality, coverage and accuracy of key clinical elements; and grade level reading formulas. RESULTS: Less than one quarter of the search engine's first pages of links led to relevant content (20% of English and 12% of Spanish). On average, 45% of the clinical elements on English- and 22% on Spanish-language Web sites were more than minimally covered and completely accurate and 24% of the clinical elements on English- and 53% on Spanish-language Web sites were not covered at all. All English and 86% of Spanish Web sites required high school level or greater reading ability. CONCLUSION: Accessing health information using search engines and simple search terms is not efficient. Coverage of key information on English- and Spanish-language Web sites is poor and inconsistent, although the accuracy of the information provided is generally good. High reading levels are required to comprehend Web-based health information.

Screening for chlamydia in adolescents and young women.

OBJECTIVE: To measure the proportion of sexually active females aged 15 to 25 years who received a screening test for Chlamydia trachomatis infection during the previous year. DESIGN: Administrative data were used to identify females in the target age range who were likely to be sexually active. Medical record data were reviewed for a sample to determine whether the administrative algorithm was acceptable. Laboratory claims data and medical record data were used to identify females who had had a screening test for chlamydia. SETTING: Four geographically dispersed US managed health care plans. PATIENTS: We studied 19,214 sexually active females aged 15 to 25 years continuously enrolled for calendar year 1997 in 1 of 4 major US health plans who had a visit to their health care provider during that year. Sexual activity was determined using an algorithm designed for use with administrative data. MAIN OUTCOME MEASURE: Rates of chlamydia screening among sexually active females aged 15 to 25 years. RESULTS: The proportion of females aged 15 to 25 years identified as sexually active by the administrative data algorithm in the 4 health plans was similar (43%-54%; P =.79). However, substantial variation was found in rates of chlamydia screening for eligible females in these 4 health plans (2%-42%; P<. 001). Plans varied considerably in the types of visits (eg, sexually transmitted disease screening or pregnancy) that determined eligibility for the measure. CONCLUSIONS: A measure of health plan performance on screening for chlamydia in young females using administrative data is feasible and provides useful results despite some flaws in estimation. There is room for improvement in rates of chlamydia screening in sexually active females aged 15 to 25 years.

Impact of sociodemographic case mix on the HEDIS measures of health plan quality.

BACKGROUND: The widely used Health Plan Employer Data and Information Set (HEDIS) measures may be affected by differences among plans in sociodemographic characteristics of members. OBJECTIVE: The objective of this study was to estimate effects of geographically linked patient sociodemographic characteristics on differential performance within and among plans on HEDIS measures. RESEARCH DESIGN: Using logistic regression, we modeled associations between age, sex, and residential area characteristics of health plan members and results on HEDIS measures. We then calculated the impact of adjusting for these associations on plan-level measures. SUBJECTS: This study included 92,232 commercially insured members with individual-level HEDIS data and an additional 20,615 members whose geographic distribution was provided. MEASURES: This study used 7 measures of screening and preventive services. RESULTS: Performance was negatively associated with percent receiving public assistance in the local area (6 of 7 measures), percent black (5 measures), and percent Hispanic (2 measures) and positively associated with percent college educated (6 measures), percent urban (2 measures), and percent Asian (1 measure) after controlling for plan and product type. These effects were generally consistent across plans. When measures were adjusted for these characteristics, rates for most plans changed by less than 5 percentage points. The largest change in the difference between plans ranged from 1.5% for retinal exams for people with diabetes to 20.2% for immunization of adolescents. CONCLUSIONS: Performance on quality indicators for individual members is associated with sociodemographic context. Adjustment has little impact on the measured performance of most plans but a substantial impact on a few. Further study with more plans is required to determine the appropriateness and feasibility of adjustment.

Defining and measuring quality of care: a perspective from US researchers.

The modern quality field in medicine is about one-third of a century old. The purpose of this paper is to summarize what we know about quality of care and indicate what we can do to improve quality of care in the next century. We assert that quality can be measured, that quality of care varies enormously, that improving quality of care is difficult, that financial incentives directed at the health system level have little effect on quality, and that we lack a publicly available tool kit to assess quality. To improve quality of care we will need adequate data and that will require patients to provide information about what happened to them and to allow people to abstract their medical records. It also will require that physicians provide patient information when asked. We also need a strategy to measure quality and then report the results and we need to place in the public domain tool kits that can be used by physicians, administrators, and patient groups to assess and improve quality. Each country should have a national quality report, based on standardized comprehensive and scientifically valid measures, which describes the country's progress in improving quality of care. We can act now. For the 70-100 procedures that dominate what physicians do, we should have a computer-based, prospective system to ensure that physicians ask patients the questions required to decide whether to do the procedure. The patient should verify the responses. Answers from patients should be combined with test results and other information obtained from the patient's physician to produce an assessment of the procedure's appropriateness and necessity. Advanced tools to assess quality, based on data from the patient and medical records, are also currently being developed. These tools could be used to comprehensively assess the quality of primary care across multiple conditions at the country, regional, and medical group level.

Measuring antidepressant prescribing practice in a health care system using administrative data: implications for quality measurement and improvement.

BACKGROUND: Up to one in eight Americans experiences an episode of depression that requires treatment in his or her lifetime. The direct and indirect costs associated with major depression are high but may be reduced with appropriate treatment. To decrease the probability of relapse, guidelines specify that treatment with antidepressant medications should continue for at least 4 months after symptom remission and that adequate doses of antidepressants be used. A study was conducted in 1997-1999 to examine how different specifications in the construction of quality of care measures for depression treatment influence conclusions about the adequacy of antidepressant prescribing practices. METHODS: Subjects were all adult members of two United Healthcare plans who each had at least one outpatient or inpatient claim with a diagnosis of depression during the years 1993-1995 and were continuously enrolled for 12 months. Pharmacy claims data were used to construct measures of duration of treatment, dose, and type of antidepressant. The effects of two different definitions of a new episode (4-month versus 9-month clean period) and two different ways of identifying an episode of depression (one visit versus two visits with a code for depression) were examined on conclusions about adequacy of antidepressant prescribing practices (dose and duration). Whether antidepressant type was related to the likelihood that antidepressants were prescribed at therapeutic doses was also examined. RESULTS: Patients with two or more visits with depression diagnosis codes were significantly more likely to receive antidepressants than those with only one visit, and were more likely to receive therapeutic doses at each time period (1-5 months). The duration of the clean period was not related to conclusions about therapeutic dosing. Among persons receiving antidepressants, those receiving selective serotonin reuptake inhibitors (SSRIs) were more likely to receive therapeutic doses and to continue treatment for at least 5 months than were those prescribed other classes of antidepressants. In multivariate analysis, being prescribed an SSRI versus another class of antidepressants was significantly associated with receiving both 1 month (OR = 7.3 [5.7-9.3]) and 5 months (OR = 2.0 [1.6-2.5]) of therapeutic treatment. DISCUSSION: Conclusions regarding the appropriateness of antidepressant prescribing can vary markedly, depending on how the quality measure is specified. Given that administrative data are and will continue to be used for both monitoring and quality improvement purposes in the short run, it is critical that we understand how variations in measurement specifications influence the conclusions that are drawn about treatment of depression in health plans.

Evaluating the quality of cancer care: development of cancer quality indicators for a global quality assessment tool.

BACKGROUND: The rise of managed care has increased interest in measuring, reporting, and improving quality of care. To date, quality assessment has relied on a leading indicator approach, which may miss important variations in care. The authors developed cancer specific indicators using a novel case-based approach for a quality measurement tool designed to compare different managed care organizations. METHODS: Based on a review of the literature, quality indicators were developed for 6 types of cancer and the human immunodeficiency virus (HIV) as well as 39 general adult conditions (GAC). The validity and feasibility of these candidate indicators were evaluated using three modified Delphi expert panels. The strength of evidence, type of care (preventive, acute, or chronic), function (screening, diagnosis, treatment, and follow-up), and modality (history, physical examination, laboratory, medication, or other intervention) of the cancer/HIV quality indicators were compared with indicators developed for GAC. RESULTS: The final system included 117 of the 145 proposed cancer/HIV quality indicators (81%) and 569 of the 705 proposed GAC indicators (81%). A greater percentage of the cancer/HIV indicators were based on evidence from clinical trials compared with the GAC indicators (59% vs. 31%; P = 0.001). Cancer/HIV had significantly more indicators pertaining to chronic care than did GAC (74% vs. 56%; P = 0.001) as well as more indicators for treatment (53% vs. 39%; P = 0.004). CONCLUSIONS: Using the case-based approach, it is feasible to develop quality indicators for cancer that cover the continuum of care. Future studies will evaluate the reliability and validity of measurements made using these indicators in three managed care plans.

Outcome measurement in HEDIS: can risk adjustment save the low birth weight measure?

OBJECTIVE: To evaluate whether adjusting the Health Plan Employer Data and Information Set (HEDIS) low birth weight (LBW) measure for maternal risk factors is feasible and improves its validity as a quality indicator. DATA SOURCE: The Washington State Birth Event Record Data for calendar years 1989 and 1990, including birth certificate data matched with mothers' and infants' hospital discharge records, with 5,837 records of singlet on infants identified as LBW (< 2,500 g) and a 25 percent sample ( n = 31,570) of the normal-weight births (

Health and cost-benefits of chlamydia screening in young women.

BACKGROUND: The Health Plan Employer Data and Information Set (HEDIS) is a set of performance measures used to assess the quality of care delivered in managed care plans. New measures that address unevaluated areas of care are continuously being developed. Chlamydia screening among young women is one new measure that was recently adopted by the National Committee for Quality Assurance (NCQA) for inclusion in HEDIS. An essential criterion for new measures is that the clinical intervention is beneficial to health and cost-effective. GOAL: To assess the health benefits and cost-effectiveness of chlamydia screening among young women. STUDY DESIGN: A focused review of the literature was performed using Medline. Articles addressing the epidemiology of chlamydia infection, its health consequences, and the benefits, problems, and cost-effectiveness associated with chlamydia screening are reviewed. RESULTS: The literature reviewed shows scientific and cost-effectiveness data that support the adoption of the HEDIS measure for chlamydia screening among young women. CONCLUSION: The National Committee for Quality Assurance's recent adoption of the measure for chlamydia screening among young women into the formal HEDIS measurement set is justifiable from a health benefit standpoint and from a cost-effectiveness standpoint.

The relationship between perceived parental expectations and pediatrician antimicrobial prescribing behavior.

CONTEXT: Despite growing concern over the escalating antimicrobial resistance problem, physicians continue to inappropriately prescribe. It has been suggested that a major determinant of pediatrician antimicrobial prescribing behavior is the parental expectation that a prescription will be provided. OBJECTIVES: To explore the extent to which parental previsit expectations and physician perceptions of those expectations are associated with inappropriate antimicrobial prescribing; and to explore the relationship between fulfillment of expectations and parental visit-specific satisfaction. DESIGN: Previsit and postvisit survey of parents and postvisit survey of physicians. SETTING: Two private pediatric practices, one community based and one university based. PARTICIPANTS: Ten physicians (response rate = 77%), and a consecutive sample of 306 eligible parents (response rate = 86%) who were attending sick visits for their children between October 1996 and March 1997. Parents were screened for eligibility in the waiting rooms of the two practices and were invited to participate if they spoke and read English and their child was 2 to 10 years old, had a presenting complaint of ear pain, throat pain, cough, or congestion, was off antimicrobial therapy for the past 2 weeks, and was seeing one of the participating physicians. MAIN OUTCOME MEASURES: Antimicrobial prescribing decision, probability of assigning a bacterial diagnosis, and parental visit-specific satisfaction. RESULTS: Based on multivariate analysis, physicians' perceptions of parental expectations for antimicrobials was the only significant predictor of prescribing antimicrobials for conditions of presumed viral etiology; when physicians thought a parent wanted an antimicrobial, they prescribed them 62% of the time versus 7% of the time when they did not think the parent wanted antimicrobials. However, physician antimicrobial prescribing behavior was not associated with actual parental expectations for receiving antimicrobials. In addition, when physicians thought the parent wanted an antimicrobial, they were also significantly more likely to give a bacterial diagnosis (70% of the time versus 31% of the time). Failure to meet parental expectations regarding communication events during the visit was the only significant predictor of parental satisfaction. Failure to provide expected antimicrobials did not affect satisfaction. CONCLUSIONS: The antibiotic resistance epidemic should lead to immediate replication of this study in a larger more generalizable population. If inaccurate physician perceptions of parent desires for antimicrobials for viral infections are confirmed, then an intervention to change the way physicians acquire this set of perceptions should be undertaken.

Services to families of adults with schizophrenia: from treatment recommendations to dissemination.

OBJECTIVE: Data from the Schizophrenia Patient Outcomes Research Team project were examined to determine the extent to which families of adults with schizophrenia receive services and whether training staff in the provision of family services increases service availability. METHODS: For patients with a diagnosis of schizophrenia, paid claims for family therapy were identified in 1991 in a nationally representative sample of Medicare data and one state's Medicaid data. In a field study in two states, 530 patients were asked about services received by their families. A quasiexperimental dissemination of a family intervention was done at nine agencies; staff at four agencies received a standard didactic presentation, and staff at five received that standard presentation paired with intensive training. RESULTS: In the representative national Medicare sample of 15,425 persons with schizophrenia, .7 percent (N=108) had an outpatient claim for family therapy. This figure was 7.1 percent in the Medicaid sample of 5,393 persons with schizophrenia in one state. Of the 530 patients in the field study who reported having contact with their families, 159 (30 percent) reported that their families had received information, advice, or support about their illness, and 40 (8 percent) responded that their families had attended an educational or support program. At the four agencies where staff received only didactic training, no changes in family services were found after one year. Three of the five agencies where staff participated in intensive training enhanced their family services. CONCLUSIONS: A minority of families of persons with schizophrenia receive information about the illness from providers. Implementation of model family interventions is possible with considerable technical assistance. A gap exists between best practices and standard practices for families of persons with schizophrenia.

Choosing and evaluating clinical performance measures.

BACKGROUND: The importance and utility of routine externally reported assessments of the quality of health care delivered in managed care organizations and hospitals have become widely accepted. Because externally reported measures of quality are intended to inform or lead to action, proposers of such measures have a responsibility to ensure that the results of the measures are meaningful, scientifically sound, and interpretable. CRITERIA FOR SELECTING MEANINGFUL ASSESSMENT AREAS: In choosing clinical performance measures to distinguish among health plans, the condition should have a significant impact on morbidity and/or mortality; the link between the measured processes and outcomes of care should have been established empirically; quality in this area should be variable or substandard currently; and health plans and/or providers should be able to take clinically sensible actions to enhance performance on the measure. CRITERIA FOR ASSESSING SCIENTIFIC SOUNDNESS: Scientific soundness--the likelihood that a clinical performance measure will produce consistent and credible results when implemented--involves precision of specifications, adaptability, and adequacy of risk adjustment. INTERPRETABILITY OF RESULTS: Interpretability is affected by the content of the measure and the audience. Measures that are clinically detailed and specific may be presented more generally to a consumer audience and in full detail to a clinical audience, but measures that are general by nature cannot be made more clinically detailed. Interpretability entails statistical analysis, calibration of measures, modeling, and presentation of information. CONCLUSIONS: Increased standardization of both the expectations for public release on measures of quality and the criteria by which such measures will be evaluated should contribute to improvements in the larger field of quality assessment.