9,363 research outputs found
Neutron spectrometer for fast nuclear reactors
In this paper we describe the development and first tests of a neutron
spectrometer designed for high flux environments, such as the ones found in
fast nuclear reactors. The spectrometer is based on the conversion of neutrons
impinging on Li into and whose total energy comprises the
initial neutron energy and the reaction -value. The LiF layer is
sandwiched between two CVD diamond detectors, which measure the two reaction
products in coincidence. The spectrometer was calibrated at two neutron
energies in well known thermal and 3 MeV neutron fluxes. The measured neutron
detection efficiency varies from 4.2 to 3.5 for
thermal and 3 MeV neutrons, respectively. These values are in agreement with
Geant4 simulations and close to simple estimates based on the knowledge of the
Li(n,) cross section. The energy resolution of the spectrometer
was found to be better than 100 keV when using 5 m cables between the detector
and the preamplifiers.Comment: submitted to NI
Impairment of the autophagic flux in astrocytes intoxicated by trimethyltin
Autophagy is a lysosomal catabolic route for protein aggregates and damaged organelles which in different stress conditions, such as starvation, generally improves cell survival. An impairment of this degradation pathway has been reported to occur in many neurodegenerative processes. Trimethyltin (TMT) is a potent neurotoxin present as an environmental contaminant causing tremors, seizures and learning impairment in intoxicated subjects. The present data show that in rat primary astrocytes autophagic vesicles (AVs) appeared after few hours of TMT treatment. The analysis of the autophagic flux in TMT-treated astrocytes was consistent with a block of the late stages of autophagy and was accompanied by a progressive accumulation of the microtubule associated protein light chain 3 (LC3) and of p62/SQSTM1. Interestingly, an increased immunoreactivity for p62/SQSTM1 was also observed in hippocampal astrocytes detected in brain slices of TMT-intoxicated rats. The time-lapse recordings of AVs in EGFP-mCherry-LC3B transfected astrocytes demonstrated a reduced mobility of autophagosomes after TMT exposure respect to control cells. The observed block of the autophagic flux cannot be overcome by known autophagy inducers such as rapamycin or 0.5mM lithium. Although ineffective when used at 0.5mM, lithium at higher concentrations (2mM) was able to protect astrocyte cultures from TMT toxicity. This effect correlated well with its ability to determine the phosphorylation/inactivation of glycogen kinase synthase-3β (GSK-3β)
COVID-19 related lockdown: a trigger from the pre-melancholic phase to catatonia and depression, a case report of a 59 year-old man
Background: The pre-melancholic model described by Tellenbach may provide a common model for understanding the psychological implications of the lockdown. In this case report, we describe a rare catatonic status as a psychological implication linked to the COVID-19 pandemic, a really unique global situation. Case presentation: B is a 59 year-old man with mute psychiatric anamnesis whose mother suffered from a major depressive disorder. As the lockdown began, he started to develop concerns about his family’s economic condition. According to his wife, he could see no end to the epidemic and no future at all. Moving from this, he started to show a severe and rapidly progressive depression and to develop mood congruent delusions. In addition, he had increasing anhedonia, apathy, starvation and insomnia. This turned in the end into a catatonic-like state, along with a deep desire to die. Admitted to the psychiatry ward in a state of mutism, he was discharged after 15 days with a diagnosis of “Major depressive disorder, single severe episode with no psychotic behavior”. He was treated with Sertraline, Olanzapine and Lorazepam. Conclusions: Our aim is to draw attention to the effect of the lockdown upon a Tellenbach-like personality structure. Identifying this type of pre-morbid personality structure could help clinicians understand and treat some cases of patients with severe major depressive disorders elicited by the COVID-19 pandemic
The role of new technologies to prevent suicide in adolescence. a systematic review of the literature
Background and objectives: Suicide in adolescents represents a major public health concern. To date, a growing number of suicide preventive strategies based on the use of new technologies are emerging. We aimed to provide an overview of the present literature on the use of new technologies in adolescent suicide prevention. Materials and methods: An electronic search was run using the following keywords: Technology OR Technologies OR APP OR Application OR mobile application) AND (Adolescent OR youth OR puberty) AND (Suicid* OR Self-harm OR self-destruction). Inclusion criteria were: English language, published in a peer-reviewed journal, suicide prevention with the use of new technologies among adolescents. Results: Our search strategy yielded a total of 12 studies on the use of telemedicine, 7 on mobile applications, and 3 on language detection. We also found heterogeneity regarding the study design: 3 are randomized controlled trials (RCT), 13 are open-label single group trials, 2 are randomized studies, and 1 is a cross-sectional study. Telemedicine was the most adopted tool, especially web-based approaches. Mobile applications mostly focused on screening of depressive symptoms and suicidal ideation, and for clinical monitoring through the use of text messages. Although telepsychiatry and mobile applications can provide a fast and safe tool, supporting and preceding a face-to-face clinical assessment, only a few studies demonstrated efficacy in preventing suicide among adolescents through the use of these interventions. Some studies suggested algorithms able to recognize people at risk of suicide from the exploration of the language on social media posts. Conclusions: New technologies were found to be well accepted and tolerated supports for suicide prevention in adolescents. However, to date, few data support the use of such interventions in clinical practice and preventive strategies. Further studies are needed to test their efficacy in suicide prevention among adolescents and young adults
Conceptualizations of suicide through time and socio-economic factors: a historical mini-review
OBJECTIVES:
Suicide is a complex phenomenon determined by the interplay of an articulated network of factors including socio-economic factors which have a decisive role. This paper investigates the development of the modern conceptualization of suicide in Europe, its sociological understandings and its intertwinement with economic cycles throughout time.
METHODS:
MEDLINE, SCHOLAR, EMBASE using the keywords 'socioeconomic factors AND suicide'; 'economic cycles AND suicide'; 'history AND suicide' without timeframe limitations. Moreover, journal-by-journal search in journals of related areas was performed.
RESULTS:
In total, 51 historical studies focusing on the subjects in European countries were included. Three main areas arose: (a) development of the conceptualization of suicide over time; (b) sociological understandings of suicide according to the structure of society and its economy of power; (c) economic theories explaining the intertwinement of economic cycles and suicides.
CONCLUSIONS:
Suicide is a deeply human phenomenon inescapably linked to and grounded in society and economic cycles. Understandings from the past show the importance of accurate analysis of socio-economic contexts that shape societies together with man's own sense of self in order to organize multi-layered tangible and intangible support strategies to better understand and prevent suicide in this day and age
Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB
The plasma-based acceleration is an encouraging technique to overcome the
limits of the accelerating gradient in the conventional RF acceleration. A
plasma accelerator is able to provide accelerating fields up to hundreds of
, paving the way to accelerate particles to several MeV over a short
distance (below the millimetre range). Here the characteristics of preliminary
electron beams obtained with the self-injection mechanism produced with the
FLAME high-power laser at the SPARC_LAB test facility are shown. In detail,
with an energy laser on focus of and a pulse temporal length (FWHM) of
, we obtained an electron plasma density due to laser ionization of
about , electron energy up to and beam
charge in the range .Comment: 6 pages, 11 figures, conference EAAC201
An integrated atom array-nanophotonic chip platform with background-free imaging
Arrays of neutral atoms trapped in optical tweezers have emerged as a leading platform for quantum information processing and quantum simulation due to their scalability, reconfigurable connectivity, and high-fidelity operations. Individual atoms are promising candidates for quantum networking due to their capability to emit indistinguishable photons that are entangled with their internal atomic states. Integrating atom arrays with photonic interfaces would enable distributed architectures in which nodes hosting many processing qubits could be efficiently linked together via the distribution of remote entanglement. However, many atom array techniques cease to work in close proximity to photonic interfaces, with atom detection via standard fluorescence imaging presenting a major challenge due to scattering from nearby photonic devices. Here, we demonstrate an architecture that combines atom arrays with up to 64 optical tweezers and a millimeter-scale photonic chip hosting more than 100 nanophotonic cavities. We achieve high-fidelity ( ~ 99.2%), background-free imaging in close proximity to nanofabricated cavities using a multichromatic excitation and detection scheme. The atoms can be imaged while trapped a few hundred nanometers above the dielectric surface, which we verify using Stark shift measurements of the modified trapping potential. Finally, we rearrange atoms into defect-free arrays and load them simultaneously onto the same or multiple devices
Can Nrf2 modulate the development of intestinal fibrosis and cancer in inflammatory bowel disease?
One of the main mechanisms carried out by the cells to counteract several forms of stress is the activation of the nuclear factor erythroid 2-related factor (Nrf2) signaling. Nrf2 signaling controls the expression of many genes through the binding of a specific cis-acting element known as the antioxidant response element (ARE). Activation of Nrf2/ARE signaling can mitigate several pathologic mechanisms associated with an autoimmune response, digestive and metabolic disorders, as well as respiratory, cardiovascular, and neurodegenerative diseases. Indeed, several studies have demonstrated that Nrf2 pathway plays a key role in inflammation and in cancer development in many organs, including the intestine. Nrf2 appears to be involved in inflammatory bowel disease (IBD), an immune-mediated chronic and disabling disease, with a high risk of developing intestinal fibrotic strictures and cancer. Currently, drugs able to increase cytoprotective Nrf2 function are in clinical trials or already being used in clinical practice to reduce the progression of some degenerative conditions. The role of Nrf2 in cancer development and progression is controversial, and drugs able to inhibit abnormal levels of Nrf2 are also under investigation. The goal of this review is to analyze and discuss Nrf2-dependent signals in the initiation and progression of intestinal fibrosis and cancers occurring in IBD
Artroplastia total no cementada en la coxartrosis secundaria a displasia y luxación congenita de cadera
Se revisan 13 prótesis no cementadas implantadas en 12 paciente s que presentaban
una coxartrosis secundaria a una displasia congénita de cadera. Los paciente s
han sido seguidos más de 2 años de evolución. En todos los casos se utilizó la via de abordaje
postero-lateral. Se implantó siempre la prótesis tipo PCA procediéndose en 7 casos a la
realización, a nivel acetabular, de un alo o autoinjerto complementario. A nivel femoral se
utilizaron 7 vástagos estándar, 3 medianos y 3 largos para facilitar la restauración del centro
rotatorio original de la cadera. En los pacientes que presentaban una luxación importante
se llevaron a cabo osteotomías de acortamiento a nivel subtrocantérico. Los pacientes
han sido evaluados pre y post-operatoriamente tanto desde el punto de vista radiográfico
como clínico. Desde el punto de vista clínico, se obtuvieron 8 resultados excelentes, 3 buenos,
1 discreto y 1 malo. Todos los pacientes estaban plenamente satisfechos con el resultado
de la operación habiendo aumentado drásticamente su nivel de actividad. Solamente en
un caso fue necesario practicar una intervención de revisión a los 4 años de la artroplastia
primitiva, a causa de una grave osificación periprotésica. Solamente se tuvo una complicación
intraoperatoria consistente en una fractura de la diálisis femoral.Thirteen non-cemented hips prostheses implanted in 12 patients with an osteoartritis
secundar y to congenita l dislocation and dysplasi a of the hip wer e reviewed .
Patients had a more than 2 years follow-up. The postero-lateral surgical approach was employed
in all cases. On the acetabular side, we always used the PCA socket type. On the femoral
side we implanted a PCA standard stem in 7 cases, mid stem in 3 cases and a long
stem in 3. Acetabular bone autograft was added in 7 patients. In order to restore the original
center of rotacion of the hip, in patients with a severe dislocation we perfomed also a shortening
sub-trochanteric osteotomy; all the patients wer e evaluated pre and post-operatively
with two separate forms. The first regarding the clinical evaluation, the second for radiographic
assessment. All the patients were fully satisfied with the operation increasing dramatically
their activity level. We obtained 8 excellent results, 3 good, 1 fair and 1 poor. One case
required a revision for a severe heterotopic bone formation about 4 years after the first implant.
We had a diaphyseal femoral fracture as the sole inly an intraoperative complication
clinical and functional outcome in a subject with bipolar disorder and severe white matter hyperintensities
Background and Objectives: Neuroimaging studies have found higher rates of white matter hyperintensities (WMHs) in patients with bipolar disorder (BD) of all ages, although whether BD is associated with increased rates of WMHs independently from age and cerebrovascular risk factors is still matter of debate. The outcome of BD associated with severe WMHs is generally poor, but several authors have suggested that some factors could have a protective role in BD. The aim of the present study was to report the two-year follow-up of a woman with BD type I and severe WMH/PWMH lesions who was taking high concentrations of vitamin-D in her nutrition, as well as taking lithium and haloperidol as treatment. Case presentation: A 76-year-old woman was hospitalized for a mixed state BD. She had severe WMHs. She took lithium and haloperidol during the hospitalization and was euthymic at discharge as well as after two-years of follow-up. Her nutrition had a high concentration of Vitamin-D. Unfortunately, it was not possible to give her a second MRI. Conclusions: Although there was probable persistence of WMHs, the patient improved in both mood and quality of life. The possible protective effect of lithium and Vitamin-D is discussed. Received: 12 January 2010 Revised: 5 August 2010 Accepted: 14 September 2010 Short report 42 GIANLUCA SERAFINI ET AL. Background and objectives Neuroimaging studies have found higher rates of WMHs in patients of all ages with bipolar disorder (BD), most frequently localized in the frontal lobes and the frontal/parietal junction1. WMHs may indicate astrogliosis, demyelination and loss of axons and may be relatively more common in older patients with BD, reflecting an interaction of the disease with processes of normal aging. However, WMHs are also associated with several pathological conditions among older individuals2. As a result of this, the meaning of these lesions in BD is still unclear. Although there have been inconsistent results in the research on this issue, WMHs are considered to be negative prognostic factors, associated with treatment resistance, increased hospitalization rates, cognitive impairment and increased suicide risk in individuals with BD3,4. However, several other factors may play a protective role in BD. Tsai et al.5 reported that psychiatric treatment, including medication with antipsychotics or lithium, could be a protective factor against early natural death. Here, we present the case of a 76year-old woman who had had a BD for twenty-one years and had, in addition, severe WMH/PWMH lesions, who was admitted to our psychiatric hospital for a mixed state. The patient gave written consent before being included in the study
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