ABSTRACT
Contact-resonance atomic force microscopy (CR-AFM) is of great interest and very valuable for a deeper understanding of the mechanics of biological materials with moduli of at least a few GPa. However, sample surfaces can present a high topography range with significant slopes, where the local angle can be as large as ⯱â¯50°. The non-trivial correlation between surface slope and CR-frequency hinders a straight-forward interpretation of CR-AFM indentation modulus measurements on such samples. We aim to demonstrate the significant influence of the surface slope on the CR-frequency that is caused by the local angle between sample surface and the AFM cantilever and present a practical method to correct the measurements. Based on existing analytical models of the effect of the AFM set-up's intrinsic cantilever tilt on CR-frequencies, we compute the non-linear variation of the first two (eigen)modes CR-frequency for a large range of surface angles. The computations are confirmed by CR-AFM experiments performed on a curved surface. Finally, the model is applied to directly correct contact modulus measurements on a durum wheat starch granule as an exemplary sample.
Subject(s)
Microscopy, Atomic Force/methods , Starch/chemistry , Triticum/chemistry , VibrationABSTRACT
Nanocomposites physical properties unexplainable by general mixture laws are usually supposed to be related to interphases, highly present at the nanoscale. The intrinsic dielectric constant of the interphase and its volume need to be considered in the prediction of the effective permittivity of nanodielectrics, for example. The electrostatic force microscope (EFM) constitutes a promising technique to probe interphases locally. This work reports theoretical finite-elements simulations and experimental measurements to interpret EFM signals in front of nanocomposites with the aim of detecting and characterizing interphases. According to simulations, we designed and synthesized appropriate samples to verify experimentally the ability of EFM to characterize a nanoshell covering nanoparticles, for different shell thicknesses. This type of samples constitutes a simplified electrostatic model of a nanodielectric. Experiments were conducted using either DC or AC-EFM polarization, with force gradient detection method. A comparison between our numerical model and experimental results was performed in order to validate our predictions for general EFM-interphase interactions.
ABSTRACT
The functionalization of surfaces with amino groups is used in many application areas such as in industrial biocatalytic processes for the development of medical biomaterials and in the environment for removing pollutants from water. Amino group density and grafting stability are often related to functionalized material performances; thus, their characterizations are of prime importance. The determination of amino density and grafting stability on polymeric material (e.g. polypropylene, polystyrene and cylco olefin copolymer) is often time consuming and sometimes presents technical constraints, more particularly with non-flat materials. In this paper, we report a novel colorimetric assay using the Coomassie Brilliant Blue dye for both amino density determination and grafting stability measurement. The assay named ADECA for "Amino Density Estimation by Colorimetric Assay" is sensitive, rapid, robust and versatile. We demonstrate that ADECA makes the evaluation of aminated materials performances possible for numerous material compositions, formats and chemistries used for grafting. Our study focuses on dendrigraft of poly-L-lysine and poly(amidoamine) dendrimers dendritic materials.
Subject(s)
Amines/chemistry , Colorimetry/methods , Dendrimers/chemistry , Dental Materials/chemistry , Surface PropertiesABSTRACT
It is shown that both dc and ac electrostatic force gradients can be observed under secondary vacuum by means of phase shifts under amplitude-controlled AFM and a double-pass method. Different flexure mode orders and electrical frequencies have been explored. A theoretical model based on the linear behaviour of the mechanical oscillator allows one to explain the experimental phase shifts and to deduce the key points governing such experiments and the expected performances. As a result, it is shown that surface voltage or Kelvin imaging becomes possible in parallel with morphology with an rms noise in the millivolt range.
ABSTRACT
El artículo hace referencia a casos clínicos de efectos adversos graves en la administración intramuscular de Penicilina Benzatínica, aún bajo observancia de buena técnica de administración. Se destacan además aspectos relevantes del procedimiento de administración de medicamentos por esta vía (AU)
Subject(s)
Humans , Male , Child , Adolescent , Adult , Penicillin G Benzathine/adverse effects , Injections, Intramuscular/adverse effects , Injections, Intramuscular/standards , Injections, Intra-Arterial/adverse effectsABSTRACT
El artículo hace referencia a casos clínicos de efectos adversos graves en la administración intramuscular de Penicilina Benzatínica, aún bajo observancia de buena técnica de administración. Se destacan además aspectos relevantes del procedimiento de administración de medicamentos por esta vía
Subject(s)
Humans , Male , Child , Adolescent , Adult , Penicillin G Benzathine/adverse effects , Injections, Intramuscular/adverse effects , Injections, Intra-Arterial/adverse effects , Injections, Intramuscular/standardsABSTRACT
UNLABELLED: This paper concerns one of the four research projects developed during a training course in clinical epidemiology managed by the Lombardy training centers IREF. OBJECTIVES: To compare the recommendations for treatment concerning 9 vignettes derived from the Australian Quality Assurance Project. SETTING: Six Mental Health Services of Regione Lombardia. DESIGN AND PARTICIPANTS: For each vignette, all psychiatrists working in the 6 Mental Health Services were asked to fill in a questionnaire about treatment location, psychopharmacology, psychotherapy, priority between psychotherapy and psychopharmacology and degree of difficulty in answering. RESULTS: 44 out of 52 target psychiatrists took part to the study. Remarkable variability for treatment location and psychotherapies; moderate variation for psychodrugs prescriptions and a good agreement for diagnoses were observed. In drugs prescription an access of association was observed. The most prevalent model of psychotherapy was the psychodynamic, followed by the cognitive-behavioural and the family-systemic. There was a tendency toward a flexible approach, as suggested by recommendations of different psychotherapeutic models according to the nature of the disorder. No case were judged very difficult; only in 3 cases a judgement of "somewhat difficult" was expressed by more than 20% (but less than 30%) of the psychiatrists. CONCLUSIONS: Studies of this type are very easy to carry out and give useful information for continuous training programs and Continuous Quality Improvement projects.
Subject(s)
Mental Disorders/therapy , Mental Health Services , Adult , Ambulatory Care , Day Care, Medical , Female , Home Care Services , Humans , Italy , Male , Mental Disorders/drug therapy , Mental Health Services/organization & administration , Mental Health Services/standards , Middle Aged , Odds Ratio , Psychotherapy , Psychotropic Drugs/therapeutic use , Quality Assurance, Health Care , Research , Surveys and QuestionnairesABSTRACT
Following an analysis of the concept of rehabilitation in psychiatry, the results of the use of the "Disability Assessment Schedule II" in a group of 50 patients (24 males and 26 females), suffering from schizophrenic psychoses, are reported. The opportuneness of a rehabilitation intervention stressed, wherever medium-severe disability levels are observed, in order to impede the affective and social destitution characteristic of chronic mental disease.