The Pursuing Excellence Collaborative: Engaging First-Year Residents and Fellows in Patient Safety Event Investigations.

OBJECTIVES: Resident and fellow engagement in patient safety event investigations (PSEIs) can benefit both the clinical learning environment's ability to improve patient care and learners' problem-solving skills. The goals of this collaborative were to increase resident and fellow participation in these investigations and improve PSEI quality. METHODS: This collaborative involved 18 sites-8 sites that had participated in a similar previous collaborative (cohort I) and 10 "new" sites (cohort II). The 18-month collaborative included face-to-face and virtual learning sessions, check-ins, and coaching calls. A validated assessment tool measured PSEI quality, and sites tracked the percentage of first-year residents and fellows included in a PSEI. RESULTS: Sixteen of the 18 sites completed the 18-month collaborative. Baseline was no first-year resident or fellow participation in a PSEI. Among these 16 clinical learning environments, 1237 early learners participated in a PSEI by the end of the collaborative. Six of these 16 sites (38%) reached the goal of 100% participation of first-year residents and fellows. As a percentage of total first-year residents and fellows, larger institutions had less resident and fellow participation. Six of the 9 cohort II sites submitted PSEIs for independent review at 6 months and again at the end of the collaborative. The PSEI quality scores increased from 5.9 ± 1.8 to 8.2 ± 0.8 ( P ≤ 0.05). CONCLUSIONS: It is possible to include all residents and fellows in PSEIs. Patient safety event investigation quality can improve through resident and fellow participation, use of standardized processes during training and investigations, and review of PSEI quality scores with a validated tool.

The impact of health literacy and socioeconomic status on asthma disparities.

OBJECTIVE: Racial/ethnic disparities have been well documented in asthma. While socioeconomic status (SES) has been repeatedly implicated as a root cause, the role of limited health literacy has not been extensively studied. The purpose of this study was to examine the independent contributions of SES and health literacy in explaining asthma disparities. METHODS: A cohort study was conducted in a Chicago-based sample of 353 adults aged 18-40 years with persistent asthma from 2004 to 2007. Health literacy, SES, and asthma outcomes including disease control, quality of life, emergency department visits, and hospitalizations were assessed in person at baseline, and asthma outcomes were measured every 3 months for 2 years by phone. Multivariate models were used to assess racial/ethnic disparities in asthma outcomes and the effect of health literacy and SES on these estimates. RESULTS: Compared with White participants, African American adults fared significantly worse in all asthma outcomes (p < .05) and Latino participants had lower quality of life (ß = -0.47; 95% confidence interval [CI] = -0.79, -0.14; p = .01) and worse asthma control (risk ratio [RR] = 0.63; 95% CI = 0.41, 0.98; p = .04). Differences in SES partially explained these disparities. Health literacy explained an additional 20.2% of differences in quality of life between Latinos and Whites, but differences in hospitalization rates between African American and White adults remained (RR = 2.97; 95% CI = 1.09, 8.12, p = .03). CONCLUSIONS: Health literacy appears to be an overlooked factor explaining racial and ethnic disparities in asthma. Evidence-based low literacy strategies for patient education and counseling should be included in comprehensive interventions.

Pay for performance through the lens of medical professionalism.

Lagging quality of care in the U.S. health care system has been a persistent problem and challenge. In the past, medical professionalism and professional certification have served as cornerstones for improving quality in health care. Among newer efforts to improve quality, pay for performance has been proposed to propel better results, but many observers are concerned that pay for performance is at odds with medical professionalism. The authors examine the potential conflicts between pay for performance and medical professionalism and conclude that properly designed pay-for-performance models can support professional objectives.

An african-specific functional polymorphism in KCNMB1 shows sex-specific association with asthma severity.

A highly heritable and reproducible measure of asthma severity is baseline pulmonary function. Pulmonary function is largely determined by airway smooth muscle (ASM) tone and contractility. The large conductance, voltage and calcium-activated potassium (BK) channel negatively regulates smooth muscle tone and contraction in ASM. The modulatory subunit of BK channels, the beta1-subunit, is critical for proper activation of BK channels in smooth muscle and has shown sex hormone specific regulation. We hypothesized that KCNMB1 genetic variants in African Americans may underlie differences in bronchial smooth muscle tone and thus pulmonary function, possibly in a sex-specific manner. Through resequencing of the KCNMB1 gene we identified several common variants including a novel African-specific coding polymorphism (C818T, R140W). The C818T SNP and four other KCNMB1 variants were genotyped in two independent groups of African American asthmatics (n = 509) and tested for association with the pulmonary function measure--forced expiratory volume (FEV(1)) % of predicted value. The 818T allele is associated with a clinically significant decline (-13%) in FEV(1) in both cohorts of asthmatics among males but not females (P(combined) = 0.0003). Patch clamp electrophysiology studies of the BK channel expressed with the 140Trp variant of the beta1-subunit demonstrated significantly reduced channel openings, predicted by the loss of pulmonary function observed. African American male asthmatics carrying the 818T allele (10% of population) are potentially at risk for greater airway obstruction and increased asthma morbidity. Female asthmatics may be insulated from the deleterious effects of the 818T allele by estrogen-mediated upregulation in BK channel activity.

Obesity and asthma morbidity in a community-based adult cohort in a large urban area: the Chicago Initiative to Raise Asthma Health Equity (CHIRAH).

BACKGROUND: Urban minority populations experience increased rates of obesity and increased asthma prevalence and severity. Objective. The authors sought to determine whether obesity, as measured by body mass index (BMI), was associated with asthma quality of life or asthma-related emergency department (ED)/urgent care utilization in an urban, community-based sample of adults. METHODS: This is a cross-sectional analysis of 352 adult subjects (age 30.9 +/- 6.1, 77.8% females, forced expiratory volume in one second (FEV(1))% predicted = 87.0% +/- 18.5%) with physician-diagnosed asthma from a community-based Chicago cohort. Outcome variables included the Juniper Asthma Quality of Life Questionnaire (AQLQ) scores and health care utilization in the previous 12 months. Bivariate tests were used as appropriate to assess the relationship between BMI or obesity status and asthma outcome variables. Multivariate regression analyses were performed to predict asthma outcomes, controlling for demographics, income, depression score, and beta-agonist use. RESULTS: One hundred ninety-one (54.3%) adults were obese (BMI > 30 kg/m(2)). Participants with a higher BMI were older (p = .008), African American (p < .001), female (p = .002), or from lower income households (p = .002). BMI was inversely related to overall AQLQ scores (r = -.174, p = .001) as well as to individual domains. In multivariate models, BMI remained an independent predictor of AQLQ. Obese participants were more likely to have received ED/urgent care for asthma than nonobese subjects (odds ratio [OR] = 1.8, p = .036). CONCLUSIONS: In a community-based sample of urban asthmatic adults, obesity was related to worse asthma-specific quality of life and increased ED/urgent care utilization. However, compared to other variables measured such as depression, the contribution of obesity to lower AQLQ scores was relatively modest.

The protective effect of community factors on childhood asthma.

BACKGROUND: Asthma burden in the US is not evenly distributed. Although asthma prevalence varies widely across urban neighborhoods, little attention has been paid to the community as a key contributor. OBJECTIVE: To determine the effect of positive socio-environmental community factors on childhood asthma prevalence in Chicago. METHODS: From 2003 to 2005, an asthma screening survey was conducted among children attending Chicago Public/Catholic schools from kindergarten through eighth grade. One hundred five schools participated, yielding a stratified representation of 4 race-income groups. Positive community factors, such as social capital, economic potential, and community amenities, were assessed by using the Metro Chicago Information Center's Community Vitality Index. RESULTS: Of the surveys returned, 45,177 (92%) were geocoded into 287 neighborhoods. Neighborhoods were divided into quartile groups by asthma prevalence (mean, 8%, 12%, 17%, 25%). Community vitality (54% vs 44%; P < .0001) and economic potential (64% vs 38%; P < .0001) were significantly higher in neighborhoods with low asthma prevalence. Neighborhood interaction (36% vs 73%; P < .0001) and stability (40% vs 53%; P < .0001) were significantly higher in neighborhoods with high asthma prevalence. Overall, positive factors explained 21% of asthma variation. Childhood asthma increased as the black population increased in a community (P < .0001). Accordingly, race/ethnicity was controlled. In black neighborhoods, these factors remained significantly higher in neighborhoods with low asthma prevalence. When considered alongside socio-demographic/individual characteristics, overall community vitality as well as social capital continued to contribute significantly to asthma variation. CONCLUSION: Asthma prevalence in Chicago is strongly associated with socio-environmental factors thought to enrich a community. A deeper understanding of this impact may lend insight into interventions to reduce childhood asthma.

Improving asthma self-efficacy: developing and testing a pilot community-based asthma intervention for African American adults.

BACKGROUND: Low-income African American adults in Chicago have disproportionately high asthma morbidity and mortality rates. Interventions that improve asthma self-efficacy for appropriate self-management behaviors might ultimately improve asthma control in this population. OBJECTIVE: We sought to pilot test an intervention to improve asthma self-efficacy for appropriate self-management behaviors. METHODS: Participants for this trial were recruited through 2 primary care clinics located in the largest African American community in Chicago. Participants were then randomized into one of 2 groups. The control group received mailed asthma education materials. The intervention group was offered 4 group sessions led by a community social worker and 6 home visits by community health workers. Telephone interviews were conducted at baseline (before intervention), 3 months (after intervention), and 6 months (maintenance). RESULTS: The 42 participants were predominantly African American and low income and had poorly controlled persistent asthma. The intervention group had significantly higher asthma self-efficacy at 3 months (P < .001) after the completion of the intervention. Asthma action plans were more common in the intervention group at 3 months (P = .06). At 6 months, the intervention group had improved asthma quality of life (P = .002) and improved coping (P = .01) compared with control subjects. Trends in behavioral and clinical outcomes favored the intervention group but were not statistically significant. CONCLUSIONS: This community-based asthma intervention improved asthma self-efficacy, self-perceived coping skills, and asthma quality of life for low-income African American adults. Larger trials are needed to test the efficacy of this intervention to reduce asthma morbidity in similar high-risk populations.

Elevating Resident Voices in Health Systems Change: Lessons From the Closure of Hahnemann University Hospital.

The closure of Philadelphia's Hahnemann University Hospital (HUH) in summer 2019 brought an abrupt end to its status as a sponsor of graduate medical education (GME). The Accreditation Council for Graduate Medical Education (ACGME) provided assistance to ensure that more than 550 residents and fellows in HUH's 35 ACGME-accredited programs were able to transfer to new programs in which they could continue their education. As the ACGME joined other organizations in responding to HUH's closure, it was apparent that the voices of residents and fellows should be emphasized in regulatory processes and policies that address substantial disruptions to GME and affect their education, their daily lives, and their professional futures.

Role of the clinical learning environment in preparing new clinicians to engage in quality improvement efforts to eliminate health care disparities.

PURPOSE: The National Collaborative for Improving the Clinical Learning Environment offers guidance to health care leaders for engaging new clinicians in efforts to eliminate health care disparities. SUMMARY: To address health care disparities that are pervasive across the United States, individuals at all levels of the health care system need to commit to ensuring equity in care. Engaging new clinicians is a key element of any systems-based approach, as new clinicians will shape the future of health care delivery. Clinical learning environments, or the hospitals, medical centers, and ambulatory care clinics where new clinicians train, have an important role in this process. Efforts may include training in cultural humility and cultural competency, education about the organization's vulnerable populations, and continuous interprofessional experiential learning through comprehensive, systems-based QI efforts focused on eliminating health care disparities. CONCLUSION: By preparing and supporting new clinicians to engage in systems-based QI efforts to eliminate health care disparities, clinical learning environments are instilling skills and supporting behaviors that clinicians can build throughout their careers-and helping pave the road towards equity throughout the US health care system.

Transitions of Care Consensus Policy Statement American College of Physicians-Society of General Internal Medicine-Society of Hospital Medicine-American Geriatrics Society-American College of Emergency Physicians-Society of Academic Emergency Medicine.

The American College of Physicians (ACP), Society of Hospital Medicine (SHM), Society of General Internal Medicine (SGIM), American Geriatric Society (AGS), American College of Emergency Physicians (ACEP) and the Society for Academic Emergency Medicine (SAEM) developed consensus standards to address the quality gaps in the transitions between inpatient and outpatient settings. The following summarized principles were established: 1.) Accountability; 2) Communication; 3.) Timely interchange of information; 4.) Involvement of the patient and family member; 5.) Respect the hub of coordination of care; 6.) All patients and their family/caregivers should have a medical home or coordinating clinician; 7.) At every point of transitions the patient and/or their family/caregivers need to know who is responsible for their care at that point; 9.) National standards; and 10.) Standardized metrics related to these standards in order to lead to quality improvement and accountability. Based on these principles, standards describing necessary components for implementation were developed: coordinating clinicians, care plans/transition record, communication infrastructure, standard communication formats, transition responsibility, timeliness, community standards, and measurement.

Eliminating asthma disparities: is there evidence of progress?

PURPOSE OF REVIEW: In spite of numerous efforts, asthma rates in the United States remain historically high and disparities persist among low-income and minority populations. This review assesses the current status of asthma inequities from the perspective of disease development, progression, and outcomes. RECENT FINDINGS: Recent findings highlight the complex and multifactorial nature of asthma. There is a clear line of emerging evidence suggestive of important hierarchical relationships between the predisposed or affected individual and his or her intrapersonal life, familial relationships, social networks, and broader community. SUMMARY: Approaches in basic, clinical, and translational asthma research must be modified to account for the social construct of race and to detangle complex interactions of contributing factors at and across the individual and community level. However, there are a number of obvious opportunities to dramatically reduce asthma disparities at hand.

Ethnic disparities in asthma morbidity in Chicago.

RATIONALE: The role of ethnicity and socioeconomic status in explaining variations in asthma morbidity is unclear. OBJECTIVES: To describe the magnitude of ethnic disparities in asthma morbidity in Chicago and to determine whether differences in socioeconomic status explain these disparities. METHODS: We conducted a survey of 561 school-age children and 353 young adults with asthma and measured their self-reported ethnicity, socioeconomic status (using 11 variables), and asthma morbidity (symptom frequency, asthma-specific quality of life, and frequency of severe asthma exacerbations). MEASUREMENTS AND MAIN RESULTS: White children and adults had better asthma-specific quality of life and fewer severe asthma exacerbations compared to black and Hispanic children and adults. White children also had fewer days with asthma symptoms, but among adults there were no ethnic differences in the frequency of asthma symptoms. Socioeconomic status explained a large portion of the ethnic disparities in asthma quality of life but explained little of the disparities in other aspects of asthma morbidity. CONCLUSIONS: There are large disparities across ethnic groups in Chicago in asthma quality of life and in the frequency of severe exacerbations. Differences in socioeconomic status do not fully explain these disparities.

Risk for death associated with medications for recently diagnosed chronic obstructive pulmonary disease.

BACKGROUND: Concerns exist regarding increased risk for mortality associated with some chronic obstructive pulmonary disease (COPD) medications. OBJECTIVE: To examine the association between various respiratory medications and risk for death in veterans with newly diagnosed COPD. DESIGN: Nested case-control study in a cohort identified between 1 October 1999 and 30 September 2003 and followed through 30 September 2004 by using National Veterans Affairs inpatient, outpatient, pharmacy, and mortality databases; Centers for Medicare & Medicaid Services databases; and National Death Index Plus data. Cause of death was ascertained for a random sample of 40% of those who died during follow-up. Case patients were categorized on the basis of all-cause, respiratory, or cardiovascular death. Mortality risk associated with medications was assessed by using conditional logistic regression adjusted for comorbid conditions, health care use, and markers of COPD severity. SETTING: U.S. Veterans Health Administration health care system. PARTICIPANTS: 32 130 case patients and 320 501 control participants in the all-cause mortality analysis. Of 11 897 patients with cause-of-death data, 2405 case patients had respiratory deaths and 3159 case patients had cardiovascular deaths. MEASUREMENTS: All-cause mortality; respiratory and cardiovascular deaths; and exposure to COPD medications, inhaled corticosteroids, ipratropium, long-acting beta-agonists, and theophylline in the 6 months preceding death. RESULTS: Adjusted odds ratios (ORs) for all-cause mortality were 0.80 (95% CI, 0.78 to 0.83) for inhaled corticosteroids, 1.11 (CI, 1.08 to 1.15) for ipratropium, 0.92 (CI, 0.88 to 0.96) for long-acting beta-agonists, and 1.05 (CI, 0.99 to 1.10) for theophylline. Ipratropium was associated with increased cardiovascular deaths (OR, 1.34 [CI, 1.22 to 1.47]), whereas inhaled corticosteroids were associated with reduced risk for cardiovascular death (OR, 0.80 [CI, 0.72 to 0.88]). Results were consistent across sensitivity analyses. LIMITATIONS: Current smoking status and lung function were not measured. Misclassification of cause-specific mortality is unknown. CONCLUSION: The possible association between ipratropium and elevated risk for all-cause and cardiovascular death needs further study.

Coded cause of death and timing of COPD diagnosis.

The aims of this study were to characterize causes of death among veterans with COPD using multiple cause of death coding, and to examine whether causes of death differed according to timing of COPD diagnosis. Veterans with COPD who died during a five-year follow-up period were identified from national VA databases linked to National Death Index files. Primary, secondary, underlying, and all-coded causes of death were compared between recent and preexistent COPD cohorts using proportional mortality ratios (PMRs), which compares proportion dying from specific causes as opposed to absolute risk of death. Of 26,357 decedents, 7,729 were categorized preexistent and 18,628 were recent COPD cases. Unspecified COPD was listed as underlying cause of death in a significantly greater proportion of preexistent COPD cases compared to recent cases, 20% vs 10%, PMR = 2.0 (95% CI: 1.9-2.1). A relatively higher proportion of recently diagnosed cases died from lung/bronchus, prostate, and site-unspecified cancers. Respiratory failure (J969) was rarely coded as an underlying or primary cause (< 1%), but was a second-code cause of death in 9% of recent and 12% of preexistent cases. Differences in coded causes of death between patients with a recent diagnosis of COPD compared to a preexistent diagnosis of COPD suggests that there is either coded cause-related bias or true differences in cause of death related to length of time with diagnosis. Thus, methods used to identify cohorts of COPD patients, i.e., incidence versus prevalence-based approaches, and coded cause of death can affect estimates of cause-specific mortality.

Geographic variability in childhood asthma prevalence in Chicago.

BACKGROUND: Childhood asthma prevalence has been shown to be higher in urban communities overall without an understanding of differences by neighborhood. OBJECTIVE: To characterize the geographic variability of childhood asthma prevalence among neighborhoods in Chicago. METHODS: Asthma screening was conducted among children attending 105 Chicago schools as part of the Chicago Initiative to Raise Asthma Health Equity. Additional child information included age, sex, race/ethnicity, and household members with asthma. Surveys were geocoded and linked with neighborhoods. Neighborhood information on race, education, and income was based on 2000 census data. Bivariate and multilevel analyses were performed. RESULTS: Of the 48,917 surveys, 41,255 (84.3%) were geocoded into 287 neighborhoods. Asthma prevalence among all children was 12.9%. Asthma rates varied among neighborhoods from 0% to 44% (interquartile range, 8% to 24%). Asthma prevalence (mean, SD, range) in predominantly black neighborhoods (19.9, +/-7, 4% to 44%) was higher than in predominantly white neighborhoods (11.4, +/-4.7, 2% to 30%) and predominantly Hispanic neighborhoods (12.1, +/-6.8, 0% to 29%). Although sex, age, household members with asthma, and neighborhood income significantly affected asthma prevalence, they did not explain the differences seen between neighborhoods. Race explained a significant proportion (about 80%) but not all of this variation. CONCLUSION: Childhood asthma prevalence varies widely by neighborhood within this urban environment. Adjacent areas in Chicago were identified with significantly different asthma prevalence. A better understanding of the effect of neighborhood characteristics may lend insight into potential interventions to reduce childhood asthma.

A community-based study of tobacco smoke exposure among inner-city children with asthma in Chicago.

BACKGROUND: Little is known about the level of tobacco exposure and the factors that influence exposure in children with persistent asthma. OBJECTIVE: We sought to measure tobacco smoke exposure and determine factors associated with exposure in a large urban sample of asthmatic children. METHODS: This cross-sectional study is based on a community-based cohort of 482 children (8-14 years old) with persistent asthma. Caregiver and household tobacco use were reported by the caregiver. Child tobacco smoke exposure was assessed by using salivary cotinine level. Multivariate linear regression of log-transformed salivary cotinine levels were used to characterize the relationship between smoke exposure and caregiver, household, and demographic characteristics. We used a multivariate logistic model to characterize associations with caregiver smoking. RESULTS: Overall, 68.5% of children had tobacco smoke exposure. Compared with nonexposed children, those exposed to smoking by a caregiver or another household member had cotinine levels that were 1.68 (95% CI, 1.45-1.94) or 1.40 (95% CI, 1.22-1.62) times higher, respectively. Compared with Hispanic children, African American and white/other children had 1.55 (95% CI, 1.16-2.06) and 1.59 (95% CI, 1.18-2.14) times higher cotinine levels, respectively. Child exposure was also associated with caregiver depression symptoms (odds ratio, 1.01; 95% CI, 1.01-1.02), and higher household income was protective (odds ratio, 0.73; 95% CI, 0.56-0.95). Independent predictors of caregiver smoking included a protective effect of higher education (odds ratio, 0.35; 95% CI, 0.15-0.83) and a positive association with potential problematic drug/alcohol use (odds ratio, 2.30; 95% CI, 1.39-3.83). CONCLUSIONS: Tobacco smoke exposure was high in this urban sample of asthmatic children. Caregiver smoking was strongly associated with child exposure and also was associated with lower socioeconomic status, non-Hispanic ethnicity, and depression symptoms.

A four-system comparison of patients with chronic illness: the Military Health System, Veterans Health Administration, Medicaid, and commercial plans.

We compared chronic care utilization in four major health systems in the U.S.: the military health system (TRICARE), the Department of Veterans Affairs (VA), Medicaid, and employer-sponsored commercial plans. Prevalence rates and key performance indicators were constructed from administrative data in federal fiscal year 2003 for eight chronic conditions: hypertension, major depression, diabetes, tobacco dependence, ischemic heart disease, severe mental illness, persistent asthma, and stroke. Continuously enrolled beneficiaries under 65 years old were studied: TRICARE (N = 2,963,987), VA (N = 2,114,739), Medicaid enrollees in five states (N = 5,554,974), and commercial insurance (N = 5,212,833). Condition-specific adjusted prevalence rates and measures were compared using the standardized rate ratio. For the majority of the conditions, the estimated prevalence rates were highest in the VA and Medicaid populations. Prevalence rates were generally lower in TRICARE and commercial plans. Medicaid beneficiaries had the highest hospitalization rates in four of the six conditions where hospitalization rates were measured. These results provide empirical evidence of differences in chronically ill patient populations in several of the major U.S. health insurance systems.

International variation in the prevalence of COPD (the BOLD Study): a population-based prevalence study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a growing cause of morbidity and mortality worldwide, and accurate estimates of the prevalence of this disease are needed to anticipate the future burden of COPD, target key risk factors, and plan for providing COPD-related health services. We aimed to measure the prevalence of COPD and its risk factors and investigate variation across countries by age, sex, and smoking status. METHODS: Participants from 12 sites (n=9425) completed postbronchodilator spirometry testing plus questionnaires about respiratory symptoms, health status, and exposure to COPD risk factors. COPD prevalence estimates based on the Global Initiative for Chronic Obstructive Lung Disease staging criteria were adjusted for the target population. Logistic regression was used to estimate adjusted odds ratios (ORs) for COPD associated with 10-year age increments and 10-pack-year (defined as the number of cigarettes smoked per day divided by 20 and multiplied by the number of years that the participant smoked) increments. Meta-analyses provided pooled estimates for these risk factors. FINDINGS: The prevalence of stage II or higher COPD was 10.1% (SE 4.8) overall, 11.8% (7.9) for men, and 8.5% (5.8) for women. The ORs for 10-year age increments were much the same across sites and for women and men. The overall pooled estimate was 1.94 (95% CI 1.80-2.10) per 10-year increment. Site-specific pack-year ORs varied significantly in women (pooled OR=1.28, 95% CI 1.15-1.42, p=0.012), but not in men (1.16, 1.12-1.21, p=0.743). INTERPRETATION: This worldwide study showed higher levels and more advanced staging of spirometrically confirmed COPD than have typically been reported. However, although age and smoking are strong contributors to COPD, they do not fully explain variations in disease prevalence-other factors also seem to be important. Although smoking cessation is becoming an increasingly urgent objective for an ageing worldwide population, a better understanding of other factors that contribute to COPD is crucial to assist local public-health officials in developing the best possible primary and secondary prevention policies for their regions.