1,793 research outputs found
Water activity in lamellar stacks of lipid bilayers: "Hydration forces" revisited
Water activity and its relationship with interactions stabilising lamellar
stacks of mixed lipid bilayers in their fluid state are investigated by means
of osmotic pressure measurements coupled with small-angle x-ray scattering. The
(electrically-neutral) bilayers are composed of a mixture in various
proportions of lecithin, a zwitterionic phospholipid, and Simulsol, a non-ionic
cosurfactant with an ethoxylated polar head. For highly dehydrated samples the
osmotic pressure profile always exhibits the "classical" exponential decay as
hydration increases but, depending on Simulsol to lecithin ratio, it becomes
either of the "bound" or "unbound" types for more water-swollen systems. A
simple thermodynamic model is used for interpreting the results without
resorting to the celebrated but elusive "hydration forces"Comment: 24 pages, 12 figures. Accepted for publication in The European
Physical Journal
INTORNO A NOVATI. ERUDIZIONE E CONOSCENZA STORICO-ARTISTICA IN ITALIA, 1880-1915
This thesis offers a wide selection and a synopsis of many previously unpublished letters excavated from the Novati correspondance Nachlass, Biblioteca Nazionale Braidense, Milan, and is focused on correspondences concerning art historical and cultural interests of Francesco Novati, 1859-1915
iPSCs-Based Neural 3D Systems: A Multidimensional Approach for Disease Modeling and Drug Discovery
Induced pluripotent stem cells (iPSCs)-based two-dimensional (2D) protocols have offered invaluable insights into the pathophysiology of neurological diseases. However, these systems are unable to reproduce complex cytoarchitectural features, cell-cell and tissue-tissue interactions like their in vivo counterpart. Three-dimensional (3D)-based culture protocols, though in their infancy, have offered new insights into modeling human diseases. Human neural organoids try to recapitulate the cellular diversity of complex tissues and can be generated from iPSCs to model the pathophysiology of a wide spectrum of pathologies. The engraftment of iPSCs into mice models and the improvement of differentiation protocols towards 3D cultures has enabled the generation of more complex multicellular systems. Consequently, models of neuropsychiatric disorders, infectious diseases, brain cancer and cerebral hypoxic injury can now be investigated from new perspectives. In this review, we consider the advancements made in modeling neuropsychiatric and neurological diseases with iPSC-derived organoids and their potential use to develop new drugs
Ecumenical modal logic
The discussion about how to put together Gentzen's systems for classical and
intuitionistic logic in a single unified system is back in fashion. Indeed,
recently Prawitz and others have been discussing the so called Ecumenical
Systems, where connectives from these logics can co-exist in peace. In Prawitz'
system, the classical logician and the intuitionistic logician would share the
universal quantifier, conjunction, negation, and the constant for the absurd,
but they would each have their own existential quantifier, disjunction, and
implication, with different meanings. Prawitz' main idea is that these
different meanings are given by a semantical framework that can be accepted by
both parties. In a recent work, Ecumenical sequent calculi and a nested system
were presented, and some very interesting proof theoretical properties of the
systems were established. In this work we extend Prawitz' Ecumenical idea to
alethic K-modalities
Validation of a bioanalytical method for the determination of synthetic and natural cannabinoids (New psychoactive substances) in oral fluid samples by means of hplc-ms/ms
New psychoactive substances (NPS) represent an important focus nowadays and are continually produced with minimal structural modifications in order to circumvent the law and increase the difficulty of identifying them. Moreover, since there are a high number of different compounds, it is arduous to develop analytical screening and/or confirmation methods that allow the identification and quantification of these compounds. The aim of this work is to develop and validate a bioanalytical method for detecting new synthetic drugs in biological samples, specifically oral fluid, using high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS/MS) with minimal sample pretreatment. Oral fluid samples were simply centrifuged and denaturized with different rapid procedures before injection into the LC-MS/MS system. Calibration curves covered a linear concentration range from LOQ to 100 ng/mL. Validation parameters such as linearity, precision, accuracy, selectivity, matrix effect and thermal stability were evaluated and showed satisfactory results, in accordance with US Food & Drug Administration guidelines. The inter-day analytical bias and imprecision at two levels of quality control (QC) were within ±15% for most compounds. This method was able to identify and calculate the concentration of 10 NPS validated in this biological sample, even in the presence of matrix effect
Antirheumatic drugs and reproduction in women and men with chronic arthritis.
The impact of rheumatic disease on fertility and reproduction can be remarkable. Many disease-related factors can influence patients' sexual functioning, perturb fertility and limit family planning. Antirheumatic pharmacological treatment can also have a crucial role in this field. Proper counselling, preferably provided by a multidisciplinary team of rheumatologists, obstetricians, gynaecologists and neonatologists, is recommended for patients taking antirheumatic drugs, not only at the beginning, but also during the course of treatment. Paternal exposure to antirheumatic drugs was not found to be specifically associated with congenital malformation and adverse pregnancy outcome, therefore discontinuation of these drugs while planning for conception should be weighed against the risk of disease flare. Drugs in Food and Drug Administration (FDA) category 'X' should be withdrawn in a timely manner in women who desire a pregnancy. Meanwhile, disease control can be achieved with anti-tumour necrosis factor (TNF)-α agents, which are not teratogenic drugs. If maternal disease control is permissive, they can be stopped as soon as the pregnancy test turns positive and be resumed during pregnancy in case of a flare
A interpretação do teste de tetrazólio em sementes de milho com o emprego da técnica de análise de imagens.
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