168 research outputs found
Magnetic Exchange Couplings from Noncollinear Spin Density Functional Perturbation Theory
We propose a method for the evaluation of magnetic exchange couplings based
on noncollinear spin-density functional calculations. The method employs the
second derivative of the total Kohn-Sham energy of a single reference state, in
contrast to approximations based on Kohn-Sham total energy differences. The
advantage of our approach is twofold: It provides a physically motivated
picture of the transition from a low-spin to a high-spin state, and it utilizes
a perturbation scheme for the evaluation of magnetic exchange couplings. The
latter simplifies the way these parameters are predicted using
first-principles: It avoids the non-trivial search for different spin-states
that needs to be carried out in energy difference methods and it opens the
possibility of "black-boxifying" the extraction of exchange couplings from
density functional theory calculations. We present proof of concept
calculations of magnetic exchange couplings in the H--He--H model system and in
an oxovanadium bimetallic complex where the results can be intuitively
rationalized.Comment: J.Chem. Phys. (accepted
Enhanced Half-Metallicity in Edge-Oxidized Zigzag Graphene Nanoribbons
We present a novel comprehensive first-principles theoretical study of the
electronic properties and relative stabilities of edge-oxidized zigzag graphene
nanoribbons. The oxidation schemes considered include hydroxyl, carboxyl,
ether, and ketone groups. Using screened exchange density functional theory, we
show that these oxidized ribbons are more stable than hydrogen-terminated
nanoribbons except for the case of the etheric groups. The stable oxidized
configurations maintain a spin-polarized ground state with antiferromagnetic
ordering localized at the edges, similar to the fully hydrogenated
counterparts. More important, edge oxidation is found to lower the onset
electric field required to induce half-metallic behavior and extend the overall
field range at which the systems remain half-metallic. Once the half-metallic
state is reached, further increase of the external electric field intensity
produces a rapid decrease in the spin magnetization up to a point where the
magnetization is quenched completely. Finally, we find that oxygen containing
edge groups have a minor effect on the energy difference between the
antiferromagnetic ground state and the above-lying ferromagnetic state.Comment: 5 pages,5 figures, 1 tabl
A Randomized Clinical Trial to Evaluate the Efficacy and Safety of the ACTLIFE Exercise Program for Women with Post-menopausal Osteoporosis: Study Protocol
Osteoporosis (OP) is a systemic disease of the skeleton characterized by increased risk of fracture. There is a general consensus on the efficacy of physical activity in the prevention of bone loss, falls and fractures, but there is no agreement on the best setting to exercise. The aim of the study is to evaluate the efficacy of a 12-months exercise protocol for women with post-menopausal OP when administered as individual home training (IHT) versus gym group training (GGT). The study is a randomized trial with two parallel groups. Sedentary patients with primary post-menopausal osteoporosis are recruited at the Istituto Ortopedico Rizzoli of Bologna. In the first group, the 12-month ACTLIFE program is performed as IHT, while in the second as GGT. The program is aimed at improving joint mobility, muscle force, balance, motor coordination and endurance. The study is single blinded. Patients are assessed at baseline and after 6 and 12 months. The primary outcome is the modification of quality of life measured with the Short Osteoporosis Quality of Life Questionnaire (ECOS-16). The findings of this study will highlight advantages and disadvantages of exercising in the two different settings and provide evidence on how to increase physical activity in osteoporotic women
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Epitaxial growth of the first two members of the Ban +1InnO2.5 n +1Ruddlesden-Popper homologous series
We demonstrate the epitaxial growth of the first two members, and the n = â member of the homologous Ruddlesden-Popper series of Ba n + 1 In n O 2.5 n + 1 of which the n = 1 member was previously unknown. The films were grown by suboxide molecular-beam epitaxy where the indium is provided by a molecular beam of indium-suboxide [In 2O (g)]. To facilitate ex situ characterization of the highly hygroscopic barium indate films, a capping layer of amorphous SiO 2 was deposited prior to air exposure. The structural quality of the films was assessed by x-ray diffraction, reflective high-energy electron diffraction, and scanning transmission electron microscopy
Loco-regional treatment with temozolomide-loaded thermogels prevents glioblastoma recurrences in orthotopic human xenograft models
Glioblastoma multiforme (GBM) is the most aggressive primary tumor of the central nervous system and the diagnosis is often dismal. GBM pharmacological treatment is strongly limited by its intracranial location beyond the bloodâbrain barrier (BBB). While Temozolomide (TMZ) exhibits the best clinical performance, still less than 20% crosses the BBB, therefore requiring administration of very high doses with resulting unnecessary systemic side efects. Here, we aimed at designing new negative temperatureâresponsive gel formulations able to locally release TMZ beyond the BBB. The biocompatibility of a chitosanâβâglycerophosphateâbased thermogel (THG)âcontaining mesoporous
SiO2 nanoparticles (THG@SiO2) or polycaprolactone microparticles (THG@PCL) was ascertained in vitro and in vivo by cell counting and histological examination. Next, we loaded TMZ into such matrices (THG@SiO2âTMZ and THG@PCLâTMZ) and tested their therapeutic potential both in vitro and in vivo, in a glioblastoma resection and recurrence mouse model based on orthotopic growth of human cancer cells. The two newly designed anticancer formulations, consisting in TMZâsilica (SiO2@TMZ) dispersed in the thermogel matrix (THG@SiO2âTMZ) and TMZ, sprayâdried on PLC and incorporated into the thermogel (THG@PCLâTMZ), induced cell death in vitro. When applied intracranially to a resected U87âMGâRedâFLuc human GBM model, THG@SiO2âTMZ and THG@PCLâ
TMZ caused a signifcant reduction in the growth of tumor recurrences, when compared to untreated controls. THG@SiO2âTMZ and THG@PCLâTMZ are therefore new promising gelâbased local therapy candidates for the treatment of GBM
A comprehensive map of CNS transduction by eight recombinant adeno-associated virus serotypes upon cerebrospinal fluid administration in pigs
Cerebrospinal fluid administration of recombinant adeno-associated viral (rAAV) vectors has been demonstrated to be effective in delivering therapeutic genes to the central nervous system (CNS) in different disease animal models. However, a quantitative and qualitative analysis of transduction patterns of the most promising rAAV serotypes for brain targeting in large animal models is missing. Here, we characterize distribution, transduction efficiency, and cellular targeting of rAAV serotypes 1, 2, 5, 7, 9, rh.10, rh.39, and rh.43 delivered into the cisterna magna of wild-type pigs. rAAV9 showed the highest transduction efficiency and the widest distribution capability among the vectors tested. Moreover, rAAV9 robustly transduced both glia and neurons, including the motor neurons of the spinal cord. Relevant cell transduction specificity of the glia was observed after rAAV1 and rAAV7 delivery. rAAV7 also displayed a specific tropism to Purkinje cells. Evaluation of biochemical and hematological markers suggested that all rAAV serotypes tested were well tolerated. This study provides a comprehensive CNS transduction map in a useful preclinical large animal model enabling the selection of potentially clinically transferable rAAV serotypes based on disease specificity. Therefore, our data are instrumental for the clinical evaluation of these rAAV vectors in human neurodegenerative diseases
Outcomes of COVID-19 patients treated with continuous positive airway pressure outside ICU
Aim We aim at characterizing a large population of Coronavirus 19 (COVID-19) patients with moderate-to-severe hypoxemic acute respiratory failure (ARF) receiving CPAP outside intensive care unit (ICU), and ascertaining whether the duration of CPAP application increased the risk of mortality for patients requiring intubation.
Methods In this retrospective, multicentre cohort study, we included COVID-19 adult patients, treated with CPAP outside ICU for hypoxemic ARF from March 1 st to April 15th, 2020. We collected demographic and clinical data, including CPAP therapeutic goal, hospital length of stay (LOS), and 60- day in-hospital mortality.
Results The study includes 537 patients with a median age of 69 (IQR, 60-76) years. Males were 391 (73%). According to predefined CPAP therapeutic goal, 397 (74%) patients were included in full treatment subgroup, and 140 (26%) in the do-not intubate (DNI) subgroup. Median CPAP duration was 4 (IQR, 1-8) days, while hospital LOS 16 (IQR, 9-27) days. Sixty-day in-hospital mortality was overall 34% (95%CI, 0.304-0.384), and 21% (95%CI, 0.169-0.249) and 73% (95%CI, 0.648-0.787) for full treatment and DNI subgroups, respectively. In the full treatment subgroup, in-hospital mortality was 42% (95%CI, 0.345-0.488) for 180 (45%) CPAP failures requiring intubation, while 2% (95%CI, 0.008- 0.035) for the remaining 217 (55%) patients who succeeded. Delaying intubation was associated with increased mortality [HR, 1.093 (95%CI, 1.010-1.184)].
Conclusions We described a large population of COVID-19 patients treated with CPAP outside ICU. Intubation delay represents a risk factor for mortality. Further investigation is needed for early identification of CPAP failures
Il farmaco: ricerca, sviluppo e applicazione in terapia
[Italiano]:Il farmaco: ricerca, sviluppo e applicazione in terapia si propone lâobiettivo di offrire una panoramica sul processo di Ricerca e Sviluppo che un farmaco compie a partire dal momento in cui viene progettato fino alla sua pratica utilizzazione. Quando una molecola è ritenuta potenzialmente adatta per creare un medicinale, si attiva un lungo percorso che ha come traguardo la realizzazione di un nuovo mezzo terapeutico e la sua approvazione per lâimmissione in commercio. Un percorso scandito dalla rigorosa osservanza di regolamenti e leggi che si sono evoluti nel tempo di pari passo con il progresso scientifico e tecnologico, ma spesso anche a seguito di reazioni avverse o eventi dannosi irreversibili che hanno innescato processi di revisione delle norme e dei protocolli sperimentali.
Questo libro parte con una densa ricognizione sulla storia della farmacologia occidentale, al fine di agevolare la comprensione del coacervo di vicende e circostanze che nel tempo hanno fatto da sfondo a tutte quelle dinamiche attraverso cui il processo di Ricerca e Sviluppo si è gradualmente affermato e consolidato. Notevole attenzione è stata poi dedicata ad alcuni risvolti divenuti oramai cruciali allâinterno dellâarticolato universo normativo in cui il farmaco è collocato, quali le terapie avanzate e i nuovi approcci per la ricerca clinica. Inoltre, gli autori si sono concentrati sulla prescrizione dei cosiddetti off-label e sulle tematiche di farmacoutilizzazione e farmacovigilanza che, nel giro di pochi decenni, sono assurte a sfere di conoscenza sempre piĂš significative e influenti nelle prospettive presenti e future, non solo delle scienze farmaceutiche ma dellâintera societĂ . Lo sforzo compiuto per redigere questo volume trova la sua ragion dâessere proprio nel voler mettere a disposizione dei lettori uno sguardo dâinsieme sul farmaco e sulle complesse sfide che ancora lo attendono./ [English]:âThe drug: research, development and application in therapyâ is an in-depth study on the Research and Development process that a drug performs from the moment it is designed up to its practical use. When a molecule is considered suitable for a medicine, a long process is activated which has as its goal the creation of a new therapeutic tool and its approval for marketing. A path marked by the strict observance of regulations and laws that have evolved over time in step with scientific and technological progress. A path that however has often been determined also by tragic events following damaging adverse reactions that have triggered processes of revision of the norms and experimental protocols. This book starts with a summary on the history of Western pharmacology, written to allow the reader to understand the circumstances that have been the background to those dynamics through which the Research and Development process has gradually consolidated. An important part of the book is dedicated to some aspects that are crucial in the normative universe in which the drug is placed, such as the advanced therapies and new approaches for clinical research. The authors also focused on the prescriptions of off-label drugs and on the issues of pharmacoutilization and pharmacovigilance, two disciplines that, in a few years, have become increasingly influential in the present and future perspectives, not only of the pharmaceutical sciences but of the entire society
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