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Novel hybrid admixtures for construction applications were prepared by layer-by-layer deposition technique. Colloidal core templates consisting of styrene/n-butylacrylate latex particles were coated with multilayers of superplasticizers commonly used in concrete. This way, core-shell particles possessing both dispersing and film-forming properties were achieved. Incorporation of the latex@dispersant hybrid additive into a cement paste results in a slow release of the superplasticizer as a result of gradual shell disintegration which instigates prolonged plastification (long ”slump life”) of the cement slurry. Once the shell has been dissolved, latex particles are released into the pore solution and can coalesce into a polymer film which improves the mechanical properties of the hardened cement. Characterization of the templates and novel additives was performed by means of zeta potential measurement, dynamic light scattering and electron microscopy. Our method allows to synthesize multifunctional additives with time-controlled release effect.
Novel microcapsules were prepared from colloidal core–shell particles by acid dissolution of the organic core. Weakly crosslinked, monodisperse and spherical melamine-formaldehyde polycondensate particles (diameter ∼ 1 μm) were synthesized as core template and coated with multilayers of an anionic polyelectrolyte via layer-by-layer deposition technique. As polyelectrolytes, an anionic naphthalenesulfonate formaldehyde polycondensate that is a common concrete superplasticizer and thus industrially available, and cationic poly(allylamine hydrochloride) were used. Core removal was achieved by soaking the core–shell particles in aqueous hydrochloric acid at pH 1.6, resulting in hollow microcapsules consisting of the polyelectrolytes. Characterization of the template, the core–shell particles, and the microcapsules plus tracking of the layer-by-layer polyelectrolyte deposition was performed by means of zeta potential measurement and scanning electron microscopy. The microcapsules might be useful as microcontainers for cement additives.
Several methods were employed to study the time dependent film formation of a self synthesized anionic latex dispersion in water and cement pore solution. First, a model carboxylated styrene/n-butyl acrylate latex dispersion possessing a minimum film forming temperature (MFFT) of 18 °C and a glass transition temperature (Tg) of 30 °C was synthesized via emulsion polymerization. Next, its film forming behaviour was studied at 40 °C, using an ESEM instrument. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. Film formation is significantly hindered in synthetic cement pore solution. This effect can be ascribed to adsorption of Ca2+ ions onto the surface of the anionic latex particles and to interfacial secondary phases. This layer of adsorbed Ca2+ ions hinders interdiffusion of the macromolecules and subsequent film formation of the latex polymer.
People can exert control over the contents of their memory and can intentionally forget information when cued to do so. The present study examined such intentional forgetting in older adults using the listwise directed forgetting (DF) task. We replicated prior work by finding intact forgetting in young-old adults (up to 75 years). Extending the prior work, we additionally found forgetting to decline gradually with individuals' age and to be inefficient in old-old adults (above 75 years). The results indicate that listwise DF is a late-declining capability, suggesting a deficit in very old adults' episodic memory control.
The Bode catchment (Germany) shows strong land use gradients from forested parts of the National Park (23 % of total land cover) to agricultural (70 %) and urbanised areas (7 %). It is part of the Terrestrial Environmental Observatories of the German Helmholtz association. We performed a biogeochemical analysis of the entire river network. Surface water was sampled at 21 headwaters and at ten downstream sites, before (in early spring) and during the growing season (in late summer). Many parameters showed lower concentrations in headwaters than in downstream reaches, among them nutrients (ammonium, nitrate and phosphorus), dissolved copper and seston dry mass. Nitrate and phosphorus concentrations were positively related to the proportion of agricultural area within the catchment. Punctual anthropogenic loads affected some parameters such as chloride and arsenic. Chlorophyll a concentration and total phosphorus in surface waters were positively related. The concentration of dissolved organic carbon (DOC) was higher in summer than in spring, whereas the molecular size of DOC was lower in summer. The specific UV absorption at 254 nm, indicating the content of humic substances, was higher in headwaters than in downstream reaches and was positively related to the proportion of forest within the catchment. CO2 oversaturation of the water was higher downstream compared with headwaters and was higher in summer than in spring. It was correlated negatively with oxygen saturation and positively with DOC concentration but negatively with DOC quality (molecular size and humic content). A principle component analysis clearly separated the effects of site (44 %) and season (15 %), demonstrating the strong effect of land use on biogeochemical parameters.
The paper demonstrates how institutional ethnography provides a way forward for occupational scientists to understand how social policies shape and infiltrate people's daily lives and work. Institutional ethnography is a method of inquiry that starts in individual's experiences and from there traces how their experiences are coordinated to and become shaped within particular organizational processes and social relations. In this paper, we are specifically interested in how social policies, as higher order texts, shape the organizational processes and service agents' work at Labor Market Offices, and enter into the organization of people's everyday activities. We want to make visible how particular policies enter into the organization of the daily lives of women with rheumatoid arthritis who apply for unemployment benefits and ‘regulate’ what they can or may have to do, even though higher order policy texts are not immediately visible or actively referred to in the setting. We learn from the experiences of two women, who are of employable age, have been diagnosed with rheumatoid arthritis, and live in a mid-sized city in Austria.
Background
Joint contractures are frequent in older individuals in geriatric care settings. Even though they are used as indicator of quality of care, there is neither a common standard to describe functioning and disability in patients nor an established standardized assessment to describe and quantify the impact of joint contractures on patients’ functioning. Thus, the aim of our study is (1) to develop a standard set for the assessment of the impact of joint contractures on functioning and social participation in older individuals and (2) to develop and validate a standardized assessment instrument for describing and quantifying the impact of joint contractures on the individuals’ functioning.
Methods
The standard set for joint contractures integrate the perspectives of all potentially relevant user groups, from the affected individuals to clinicians and researchers. The development of this set follows the methodology to develop an International Classification of Functioning Disability and Health (ICF) Core Set and involves a formal decision-making and consensus process. Evidence from four preparatory studies will be integrated including qualitative interviews with patients, a systematic review of the literature, a survey with health professionals, and a cross sectional study with patients affected by joint contractures. The assessment instrument will be developed using item-response-theory models. The instrument will be validated.
Discussion
The standard set for joint contractures will provide a list of aspects of functioning and health most relevant for older individuals in geriatric care settings with joint contractures. This list will describe body functions, body structures, activities and participation and related environmental factors. This standard set will define what aspects of functioning should be assessed in individuals with joint contractures and will be the basis of the new assessment instrument to evaluate the impact of joint contractures on functioning and social participation.
Background Free movement of the limbs is a prerequisite of mobility and autonomy in old age. Joint contractures, i.e. restrictions in full range of motion of any joint due to deformity, disuse or pain, are common problems of frail older people, particularly in nursing home residents.
Contractures are among the most unexplored and underreported syndromes in clinical and homecare settings. Epidemiological studies indicate a wide range of prevalence of joint contractures in older individuals between 20% and 80%. This variation is due to different definitions of contracture and varying diagnostic criteria or data collection methods, different research settings, sample size and study participants? characteristics.
The aetiology of joint contractures is multifaceted. In older people contractures may be caused by a variety of health conditions and situations, but immobility due to an acute injury or disease seems to be the major risk factor. Upper limb joint contractures may result in loss of ability to dress or eat independently while lower limb contractures may lead to instability and inability to walk independently and higher risk of bed confinement.
Joint contractures further increase the risk of other adverse patient outcomes like pain, pressure ulcers and risk of falls. Thus, joint contractures are a major cause for excess disability in older people with a significant impact on overall quality of life and functioning. Preventive and rehabilitation interventions targeting joint contractures may decrease morbidity, increase functioning and quality of life, and, ultimately, prevent long-term disability. In the United States of America, presence of joint contractures is an established indicator of quality of care in nursing facilities.
In Germany, joint contracture risk assessment and prevention have recently been defined as a quality indicator of nursing home care that should be regularly monitored by experts from the statutory health insurance system. Nursing homes are obliged to report whether they regularly assess the risk of joint contracture and administer relevant preventive measures. In clinical settings, joint contractures are assessed by measuring the range of motion.
However, from a patient- and nursing-oriented perspective the relevance of a systematic registration of contractures in care-dependent older people is unclear unless their impact on functioning is understood. Contracture assessment is only an intermediate step in the evaluation of patient-relevant outcomes such as quality of life, functioning, and the ability to participate in everyday life and social participation. Arguably, a clinical definition of joint contracture is difficult because the contracture?s severity is determined by the consequences on activities of daily living, quality of life and social participation. In addition, there is no consensus on aspects most relevant to the affected individuals.
A variety of functional measures is currently used for the assessment and evaluation of geriatric patients. To date, there is no consensus on common concepts for the choice of outcome measures specifically for evaluating the impact of interventions targeted on joint
Symptom frequency and severity in vestibular disorders often do not correlate well with patients' restrictions of activities of daily living and limitations of participation.
Due to the lack of appropriate patient reported outcome measures (PRO), the extent of limitations and restrictions is mostly unknown. The International Classification of Functioning, Disability and Health (ICF) is a conceptual framework and classification to evaluate all aspects of health and disability. An ICF-based measure, the Vestibular and Participation Measure (VAP), was recently proposed.
Also, an ICF Core Set for vertigo, dizziness and balance disorders was developed to describe what aspects of functioning should be measured. This study protocol describes the development and cross-cultural validation of a new measure, the VAP-extended (VAP-e), based on VAP and ICF Core Set on three continents.
To determine objectivity and cross-cultural validity of the VAP and to find potentially redundant items, Rasch models will be used. The VAP-e will be created by modifying or adding items from the Activities and Participation and Environmental Factors component of the ICF Core Set. Reliability, objectivity and responsiveness of the VAP-e will be tested.