Optical trapping and critical Casimir forces

Critical Casimir forces emerge between objects, such as colloidal particles, whenever their surfaces spatially confine the fluctuations of the order parameter of a critical liquid used as a solvent. These forces act at short but microscopically large distances between these objects, reaching often hundreds of nanometers. Keeping colloids at such distances is a major experimental challenge, which can be addressed by the means of optical tweezers. Here, we review how optical tweezers have been successfully used to quantitatively study critical Casimir forces acting on particles in suspensions. As we will see, the use of optical tweezers to experimentally study critical Casimir forces can play a crucial role in developing nano-technologies, representing an innovative way to realize self-assembled devices at the nano- and microscale.Comment: 18 pages, 11 figure

Correction: Controlling the dynamics of colloidal particles by critical Casimir forces.

Correction for 'Controlling the dynamics of colloidal particles by critical Casimir forces' by Alessandro Magazzù et al., Soft Matter, 2019, 15, 2152–2162, DOI: 10.1039/C8SM01376D

Controlling the dynamics of colloidal particles by critical Casimir forces

Critical Casimir forces can play an important role for applications in nano-science and nano-technology, owing to their piconewton strength, nanometric action range, fine tunability as a function of temperature, and exquisite dependence on the surface properties of the involved objects. Here, we investigate the effects of critical Casimir forces on the free dynamics of a pair of colloidal particles dispersed in the bulk of a near-critical binary liquid solvent, using blinking optical tweezers. In particular, we measure the time evolution of the distance between the two colloids to determine their relative diffusion and drift velocity. Furthermore, we show how critical Casimir forces change the dynamic properties of this two-colloid system by studying the temperature dependence of the distribution of the so-called first-passage time, i. e., of the time necessary for the particles to reach for the first time a certain separation, starting from an initially assigned one. These data are in good agreement with theoretical results obtained from Monte Carlo simulations and Langevin dynamics

Pharmacotherapy Use in Older Patients with Heart Failure and Reduced Ejection Fraction Living in Skilled Nursing Facilities

Background: Little is known about the use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) and β-blockers among older adults with heart failure and reduced ejection fraction (HFrEF) in skilled nursing facilities (SNFs). Methods: Using national data Minimum Data Set 3.0 cross-linked with Medicare data (2011-2012), we studied 31,675 patients with HFrEF (ICD-9 codes: 428.2 or 428.4) aged ≥65 years admitted to 9,659 SNFs. We estimated the prevalence of a Part D claim for ACEIs/ARBs or β-blockers during 3 months before the SNF stay and used log-binomial models to evaluate correlates of use by estimating prevalence ratios (PR) and 95% confidence intervals (CI). Results: The median age of the study population was 83 years, 60% were women, and 10% and 4% were African Americans and Hispanics, respectively. Approximately 46% had ≥3 important risk factors for HFrEF. Fifty-seven percent received an ACEI/ARB and 47% a β-blocker; 25% received neither. Older age was inversely associated with receipt of these therapies: adjusted PRs were 0.94 (95% CI: 0.91-0.96) for ACEIs/ARBs and 0.86 (95% CI: 0.84-0.89) for β-blockers for patients aged ≥85 years compared with those aged 65-74 years. Compared with Whites, use of these therapies was higher among African Americans (adjusted PRs were 1.07 [95% CI: 1.04-1.10] for ACEIs/ARBs and 1.11 [95% CI: 1.08-1.15] for β-blockers) and Hispanics (adjusted PRs were 1.13 [95% CI: 1.09-1.18] for ACEIs/ARBs and 1.12 [95% CI: 1.07-1.18] for β-blockers). The prevalence of ACEI/ARB use was greater in patients with ≥3 important risk factors than in those with ≤1 factor: adjusted PR was 1.16 (95% CI 1.13-1.19). Conclusions: Use of guideline-directed medications may be suboptimal in older patients with HFrEF receiving SNF care. Whether this is a result of adverse drug events from prior use or insufficient evidence in vulnerable populations needs to be examined. Acknowledgements: Lin Li has received funding from a National Institutes of Health Ruth L. Kirschstein National Research Service Award Institutional Research Training Grant (5T32HL120823-02

Perception of the quality of communication with physicians among relatives of dying residents of long-term care facilities in 6 European countries : PACE cross-sectional study

Objective: To examine how relatives evaluate the quality of communication with the treating physician of a dying resident in long-term care facilities (LTCFs) and to assess its differences between countries. Design: A cross-sectional retrospective study in a representative sample of LTCFs conducted in 2015. Relatives of residents who died during the previous 3 months were sent a questionnaire. Settings and participants: 761 relatives of deceased residents in 241 LTCFs in Belgium, England, Finland, Italy, the Netherlands, and Poland. Methods: The Family Perception of Physician-Family Communication (FPPFC) scale (ratings from 0 to 3, where 3 means the highest quality) was used to retrospectively assess how the quality of end-of-life communication with treating physicians was perceived by relatives. We applied multilevel linear and logistic regression models to assess differences between countries and LTCF types. Results: The FPPFC score was the lowest in Finland (1.4 +/- 0.8) and the highest in Italy (2.2 +/- 0.7). In LTCFs served by general practitioners, the FPPFC score differed between countries, but did not in LTCFs with onsite physicians. Most relatives reported that they were well informed about a resident's general condition (from 50.8% in Finland to 90.6% in Italy) and felt listened to (from 53.1% in Finland to 84.9% in Italy) and understood by the physician (from 56.7% in Finland to 85.8% in Italy). In most countries, relatives assessed the worst communication as being about the resident's wishes for medical treatment at the end of life, with the lowest rate of satisfied relatives in Finland (37.6%). Conclusion: The relatives' perception of the quality of end-of-life communication with physicians differs between countries. However, in all countries, physicians' communication needs to be improved, especially regarding resident's wishes for medical care at the end of life. Implications: Training in end-of-life communication to physicians providing care for LTCF residents is recommended

Dying in long-term care facilities in Europe : the PACE epidemiological study of deceased residents in six countries

Background: By 2030, 30% of the European population will be aged 60 or over and those aged 80 and above will be the fastest growing cohort. An increasing number of people will die at an advanced age with multiple chronic diseases. In Europe at present, between 12 and 38% of the oldest people die in a long-term care facility. The lack of nationally representative empirical data, either demographic or clinical, about people who die in long-term care facilities makes appropriate policy responses more difficult. Additionally, there is a lack of comparable cross-country data; the opportunity to compare and contrast data internationally would allow for a better understanding of both common issues and country-specific challenges and could help generate hypotheses about different options regarding policy, health care organization and provision. The objectives of this study are to describe the demographic, facility stay and clinical characteristics of residents dying in long-term care facilities and the differences between countries. Methods: Epidemiological study (2015) in a proportionally stratified random sample of 322 facilities in Belgium, Finland, Italy, the Netherlands, Poland and England. The final sample included 1384 deceased residents. The sampled facilities received a letter introducing the project and asking for voluntary participation. Facility manager, nursing staff member and treating physician completed structured questionnaires for all deaths in the preceding 3 months. Results: Of 1384 residents the average age at death ranged from 81 (Poland) to 87 (Belgium, England) (p < 0.001) and length of stay from 6 months (Poland, Italy) to 2 years (Belgium) (p < 0.05); 47% (the Netherlands) to 74% (Italy) had more than two morbidities and 60% (England) to 83% (Finland) dementia, with a significant difference between countries (p < 0.001). Italy and Poland had the highest percentages with poor functional and cognitive status 1 month before death (BANS-S score of 21.8 and 21.9 respectively). Clinical complications occurred often during the final month (51.9% England, 66.4% Finland and Poland). Conclusions: The population dying in long-term care facilities is complex, displaying multiple diseases with cognitive and functional impairment and high levels of dementia. We recommend future policy should include integration of high-quality palliative and dementia care

Comparing the Prognostic Accuracy for All-Cause Mortality of Frailty Instruments: A Multicentre 1-Year Follow-Up in Hospitalized Older Patients

Frailty is a dynamic age-related condition of increased vulnerability characterized by declines across multiple physiologic systems and associated with an increased risk of death. We compared the predictive accuracy for one-month and one-year all-cause mortality of four frailty instruments in a large population of hospitalized older patients in a prospective multicentre cohort study

Physical restraining of nursing home residents in the last week of life : an epidemiological study in six European countries

Background: End-of-life care in nursing homes holds several risk factors for the use of physical restraints on residents, a practice shown to be neither safe nor effective. Objectives: To determine the frequency of physical limb and/or trunk restraint use in the last week of life of nursing home residents in six European countries and its association with country, resident and nursing home characteristics. Design: Epidemiological survey study. Setting: Proportionally stratified random sample of nursing homes in Belgium (BE), England (ENG), Finland (FI), Italy (IT), the Netherlands (NL), and Poland (PL). Participants: Nursing home staff (nurses or care assistants). Methods: In all participating nursing homes, we identified all residents who died during the three months prior to measurements. The staff member most involved in each resident's care indicated in a structured questionnaire whether trunk and/or limb restraints were used on that resident during the last week of life 'daily', 'less frequently than daily' or not used'. Results: In 322 nursing homes, staff returned questionnaires regarding 1384 deceased residents (response rate 81%). Limb and/or trunk restraints were used "daily" in the last week of life in 8% (BE), 1% (ENG), 4% (FI), 12% (IT), 0% (NL), and 0.4% (PL) of residents; and "less frequently than daily" in 4% (BE), 0% (ENG), 0.4% (FI), 6% (IT), 0% (NL), and 3.5% (PL) of residents. Restraint use was associated with country (p = 0.020) and inversely associated with residents' age (p = 0.017; odds ratio 0.96, 95% confidence interval 0.93 to 0.99). Restraint use was not significantly associated with resident's gender, dementia, functional status, staffing level, or the level of dependency of residents within the nursing home. Conclusions: In all but one of the six countries studied, staff reported that nursing home residents were restrained through limb and/or trunk restraints in the last week of life. The proportion of restrained residents was highest in Italy and Belgium. Organizational and resident characteristics may not be relevant predictors of restraint use at the end of life in this setting. National policy that explicitly discourages physical restraints in nursing home care and suggests alternative practices may be an important component of strategies to prevent their use. (C) 2019 The Author(s). Published by Elsevier Ltd