141 research outputs found
Magnetic levitation on a type-I superconductor as a practical demonstration experiment for students
We describe and discuss an experimental set-up which allows undergraduate and
graduate students to view and study magnetic levitation on a type-I
superconductor. The demonstration can be repeated many times using one readily
available 25 liter liquid helium dewar. We study the equilibrium position of a
magnet that levitates over a lead bowl immersed in a liquid hand-held helium
cryostat. We combine the measurement of the position of the magnet with simple
analytical calculations. This provides a vivid visualization of magnetic
levitation from the balance between pure flux expulsion and gravitation. The
experiment contrasts and illustrates the case of magnetic levitation with high
temperature type-II superconductors using liquid nitrogen, where levitation
results from partial flux expulsion and vortex physics
¿Es posible crecer con equidad y en democracia?: una síntesis de la propuesta de la CEPAL
Incluye Bibliografí
Functional recovery in patients with schizophrenia: recommendations from a panel of experts
emission and encompasses multiple aspects of the patient's life, making it difficult to settle on a definition and to develop reliable assessment criteria. In this consensus process based on a panel of experts in schizophrenia, we aimed to provide useful insights on functional recovery and its involvement in clinical practice and clinical research.
Methods: After a literature review of functional recovery in schizophrenia, a scientific committee of 8 members prepared a 75-item questionnaire, including 6 sections: (I) the concept of functional recovery (9 items), (II) assessment of functional recovery (23 items), (III) factors influencing functional recovery (16 items), (IV) psychosocial interventions and functional recovery (8 items), (V) pharmacological treatment and functional recovery (14 items), and (VI) the perspective of patients and their relatives on functional recovery (5 items). The questionnaire was sent to a panel of 53 experts, who rated each item on a 9-point Liken scale. Consensus was achieved in a 2-round Delphi dynamics, using the median (interquartile range) scores to consider consensus in either agreement (scores 7-9) or disagreement (scores 1-3). Items not achieving consensus in the first round were sent back to the experts for a second consideration.
Results: After the two recursive rounds, consensus was achieved in 64 items (85.3%): 61 items (81.3%) in agreement and 3 (4.0%) in disagreement all of them from section II (assessment of functional recovery). Items not reaching consensus were related to the concepts of functional recovery (1 item, 13%), functional assessment (5 items, 6.7%), factors influencing functional recovery (3 items, 4.0%), and psychosocial interventions (2 items, 5.6%).
Conclusions: Despite the lack of a well-defined concept of functional recovery, we identified a trend towards a common archetype of the definition and factors associated with functional recovery, as well as its applicability in clinical practice and clinical research.This project was funded by Janssen. The funding body participated in study design and data interpretation
Women with psychotic episodes during pregnancy show increased markers of placental damage with Tenney-Parker changes
y. Psychosis is a hazardous and functionally
disruptive psychiatric condition which may affect
women in pregnancy, entailing negative consequences
for maternofetal well-being. The precise pathophysiological basis and consequences of a psychotic episode in
pregnancy remain to be further elucidated. The placenta
is a pivotal tissue with many functions in the gestational
period, critically influencing the fate and development of
pregnancy. Although detrimental alterations have been
observed in women undergoing severe psychiatric
disorders in pregnancy, there are little studies evaluating
the consequences of suffering from a psychotic episode
in the placental tissue In this work, we have evaluated
the histopathological consequences of a first episode of
psychosis in pregnancy (FE-PW; N=22) and compare
them with healthy pregnant women (HC-PW; N=20) by
using histological, immunohistochemical and gene
expression techniques. Our results define that the
placental tissue of FE-PW display an increase in the
number of placental villi, bridges, syncytial knots and
syncytial knots/villi. Besides, we have also observed an
enhanced gene and protein expression in FE-PW of the
hypoxic marker HIF-1α, together with the apoptotic
markers BAX and Bcl-2. To our knowledge, this is the
first study demonstrating significant histopathological
changes in the placenta of women suffering a new-onset
psychotic episode in pregnancy. Further studies should
be aimed at deepening the knowledge about the
pernicious effects of psychosis in the maternofetal
tissues, as well as the potential implications of these
alterations
What to consider when pseudohypoparathyroidism is ruled out: IPPSD and differential diagnosis
Background: Pseudohypoparathyroidism (PHP) is a rare disease whose phenotypic features are rather difficult to identify in some cases. Thus, although these patients may present with the Albright''s hereditary osteodystrophy (AHO) phenotype, which is characterized by small stature, obesity with a rounded face, subcutaneous ossifications, mental retardation and brachydactyly, its manifestations are somewhat variable. Indeed, some of them present with a complete phenotype, whereas others show only subtle manifestations. In addition, the features of the AHO phenotype are not specific to it and a similar phenotype is also commonly observed in other syndromes. Brachydactyly type E (BDE) is the most specific and objective feature of the AHO phenotype, and several genes have been associated with syndromic BDE in the past few years. Moreover, these syndromes have a skeletal and endocrinological phenotype that overlaps with AHO/PHP. In light of the above, we have developed an algorithm to aid in genetic testing of patients with clinical features of AHO but with no causative molecular defect at the GNAS locus. Starting with the feature of brachydactyly, this algorithm allows the differential diagnosis to be broadened and, with the addition of other clinical features, can guide genetic testing. Methods: We reviewed our series of patients (n = 23) with a clinical diagnosis of AHO and with brachydactyly type E or similar pattern, who were negative for GNAS anomalies, and classify them according to the diagnosis algorithm to finally propose and analyse the most probable gene(s) in each case. Results: A review of the clinical data for our series of patients, and subsequent analysis of the candidate gene(s), allowed detection of the underlying molecular defect in 12 out of 23 patients: five patients harboured a mutation in PRKAR1A, one in PDE4D, four in TRPS1 and two in PTHLH. Conclusions: This study confirmed that the screening of other genes implicated in syndromes with BDE and AHO or a similar phenotype is very helpful for establishing a correct genetic diagnosis for those patients who have been misdiagnosed with "AHO-like phenotype" with an unknown genetic cause, and also for better describing the characteristic and differential features of these less common syndromes
Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases
The production of peroxide and superoxide is an inevitable consequence of
aerobic metabolism, and while these particular "reactive oxygen species" (ROSs)
can exhibit a number of biological effects, they are not of themselves
excessively reactive and thus they are not especially damaging at physiological
concentrations. However, their reactions with poorly liganded iron species can
lead to the catalytic production of the very reactive and dangerous hydroxyl
radical, which is exceptionally damaging, and a major cause of chronic
inflammation. We review the considerable and wide-ranging evidence for the
involvement of this combination of (su)peroxide and poorly liganded iron in a
large number of physiological and indeed pathological processes and
inflammatory disorders, especially those involving the progressive degradation
of cellular and organismal performance. These diseases share a great many
similarities and thus might be considered to have a common cause (i.e.
iron-catalysed free radical and especially hydroxyl radical generation). The
studies reviewed include those focused on a series of cardiovascular, metabolic
and neurological diseases, where iron can be found at the sites of plaques and
lesions, as well as studies showing the significance of iron to aging and
longevity. The effective chelation of iron by natural or synthetic ligands is
thus of major physiological (and potentially therapeutic) importance. As
systems properties, we need to recognise that physiological observables have
multiple molecular causes, and studying them in isolation leads to inconsistent
patterns of apparent causality when it is the simultaneous combination of
multiple factors that is responsible. This explains, for instance, the
decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference
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