1,713 research outputs found
Renormalized Electron Mass in Nonrelativistic QED
Within the framework of nonrelativistic QED, we prove that, for small values
of the coupling constant, the energy function, E_|P|, of a dressed electron is
twice differentiable in the momentum P in a neighborhood of P = 0. Furthermore,
(E_|P|)" is bounded from below by a constant larger than zero. Our results are
proven with the help of iterative analytic perturbation theory
Invariant NKT cells and rheumatic disease: Focus on primary sjogren syndrome
Primary Sjogren syndrome (pSS) is a complex autoimmune disease mainly affecting salivary and lacrimal glands. Several factors contribute to pSS pathogenesis; in particular, innate immunity seems to play a key role in disease etiology. Invariant natural killer (NK) T cells (iNKT) are a T-cell subset able to recognize glycolipid antigens. Their function remains unclear, but studies have pointed out their ability to modulate the immune system through the promotion of specific cytokine milieu. In this review, we discussed the possible role of iNKT in pSS development, as well as their implications as future markers of disease activity
Widening use of dexamethasone implant for the treatment of macular edema
Sustained-release intravitreal 0.7 mg dexamethasone (DEX) implant is approved in Europe for the treatment of macular edema related to diabetic retinopathy, branch retinal vein occlusion, central retinal vein occlusion, and non-infectious uveitis. The implant is formulated in a biodegradable copolymer to release the active ingredient within the vitreous chamber for up to 6 months after an intravitreal injection, allowing a prolonged interval of efficacy between injections with a good safety profile. Various other ocular pathologies with inflammatory etioÂpathogeneses associated with macular edema have been treated by DEX implant, including neovascular age-related macular degeneration, IrvineâGass syndrome, vasoproliferative retinal tumors, retinal telangiectasia, Coatsâ disease, radiation maculopathy, retinitis pigmentosa, and macular edema secondary to scleral buckling and pars plana vitrectomy. We undertook a review to provide a comprehensive collection of all of the diseases that benefit from the use of the sustained-release DEX implant, alone or in combination with concomitant therapies. A MEDLINE search revealed lack of randomized controlled trials related to these indications. Therefore we included and analyzed all available studies (retrospective and prospective, comÂparative and non-comparative, randomized and nonrandomized, single center and multicenter, and case report). There are reports in the literature of the use of DEX implant across a range of macular edema-related pathologies, with their clinical experience supporting the use of DEX implant on a case-by-case basis with the aim of improving patient outcomes in many macular pathologies. As many of the reported macular pathologies are difficult to treat, a new treatÂment option that has a beneficial influence on the clinical course of the disease may be useful in clinical practice
Absence of Ground States for a Class of Translation Invariant Models of Non-relativistic QED
We consider a class of translation invariant models of non-relativistic QED
with net charge. Under certain natural assumptions we prove that ground states
do not exist in the Fock space
Evaluation of the burden of HPV-related hospitalizations as a useful tool to increase awareness: 2007â2017 data from the sicilian hospital discharge records
In light of the implementation of human papillomavirus (HPV) prevention strategies, epidemiological studies in different geographical areas are required in order to assess the impact of HPV-related diseases. The purpose of the present study was to describe the burden of HPV-related hospitalizations in Sicily. A retrospective observational study estimated 43,531 hospitalizations attributable to HPV from 2007 to 2017. During the observed period, there was a decrease for all HPV-related conditions with a higher reduction, among neoplasms, for cervical cancer (annual percent change (APC) = â9.9%, p < 0.001). The median age for cervical cancer was 45 years old, with an increasing value from 43 to 47 years (p < 0.001). The age classes with greater decreases in hospital admissions for invasive cancers were women aged 35 years or more (APC range from â5.5 to â9.86) and 25â34 years old (APC = â11.87, p < 0.001) for women with cervical carcinoma in situ. After ten years for vaccine introduction and sixteen years for cervical cancer screening availability, a relatively large decrease in hospital admissions for cervical cancer and other HPV-related diseases in Sicily was observed. Some clinical characteristics of hospitalization, such as increasing age, are suggestive clues for the impact of preventive strategies, but further research is needed to confirm this relationship
Indagini briologiche in aree urbane: diversitĂ briofitica dei centri abitati di Erice (Trapani) e Belmonte Mezzagno (Palermo).
Bryologic surveys in urban areas: bryophyte diversity of the population centers of Erice (province of Trapani)
and Belmonte Mezzagno ((province of Palermo). The bryophytic flora of the towns of Erice (Trapani) and Belmonte Mezzagno
(Palermo) have been studied. The first consists of 53 taxa (42 mosses and 11 liverwort), two of which are new for
the province of Trapani, the second of 40 taxa (38 mosses and 2 liverworts), one of which new for the province of Palermo.
A comparison between the studied bryofloras and those of other Sicilian urban areas shows that Ericeâs bryophytic flora is,
given its size, rich in species and families
Synthesis and Antibacterial Activity of Mono- and Bi-Cationic Pyridinium 1,2,4-Oxadiazoles and Triazoles
One of the main causes of mortality in humans continues to be infectious diseases. Scientists are searching for new alternatives due to the fast increase in resistance of some harmful bacteria to the frontline antibiotics. To effectively treat pathogenic infections, it is crucial to design antibiotics that can prevent the development of pathogenic resistance. For this purpose, a set of 39 quaternary pyridinium and bis-pyridinium salts with different lengths of side alkyl or fluorinated chains, heterocyclic spacers, and counter ions were tested on diverse reference bacterial ATCC (American Type Culture Collection) strains, such as S. aureus and E. coli. Subsequently, 6 out of the 39 pyridinium salts showing relevant MIC (Minimum Inhibitory Concentration) values were tested on clinically isolated, resistant strains of S. aureus, S. epidermids, S. haemolyticus, K. pneumoniae, A. baumannii, and P. aeruginosa. Additional tests have been performed to assess if the minimum concentration detected through MIC assay may limit the growth of biofilms
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First imaging of corotating interaction regions using the STEREO spacecraft
Plasma parcels are observed propagating from the Sun out to the large coronal heights monitored by the Heliospheric Imagers (HI) instruments onboard the NASA STEREO spacecraft during September 2007. The source region of these out-flowing parcels is found to corotate with the Sun and to be rooted near the western boundary of an equatorial coronal hole. These plasma enhancements evolve during their propagation through the HI camerasâ fields of view and only becoming fully developed in the outer camera field of view. We provide evidence that HI is observing the formation of a Corotating Interaction Region(CIR) where fast solar wind from the equatorial coronal hole is interacting with the slow solar wind of the streamer belt located on the western edge of that coronal hole. A dense plasma parcel is also observed near the footpoint of the observed CIR at a distance less than 0.1AU from the Sun where fast wind would have not had time to catch up slow wind. We suggest that this low-lying plasma enhancement is a plasma parcel which has been disconnected from a helmet streamer and subsequently becomes embedded inside the corotating interaction region
The COVID-19 Wellbeing Study: Examining perceived coercion and psychological wellbeing during the COVID-19 pandemic by means of an online survey, asynchronous virtual focus groups and individual interviews â a protocol
Introduction: The COVID-19 pandemic has resulted in
many countries applying restrictive measures, such as
lockdown, to contain and prevent further spread. The
psychological impact of lockdown and working as a
healthcare worker on the frontline has been chronicled
in studies pertaining to previous infectious disease
pandemics that have reported the presence of depressive
symptoms, anxiety, insomnia, and post-traumatic stress
symptoms. Potentially linked to psychological well-being
and not yet studied is the possibility that lockdown and
working on the frontline of the pandemic are associated
with perceptions of coercion.
Methods and analysis: The present study aimed
to examine perceived coercion in those who have
experienced COVID-19-related lockdown and/or worked
as a frontline healthcare worker across three European
countries. It aimed to describe how such perceptions may
impact on psychological well-being, coping and posttraumatic growth. It will employ an explanatory mixedmethods research methodology consisting of an online
survey and online asynchronous virtual focus groups
(AVFGs) and individual interviews. Ï2
tests and analyses
of variance will be used to examine whether participants
from different countries differ according to demographic
factors, whether there are differences between cohorts on
perceived coercion, depression, anxiety and post-traumatic
growth scores. The relationship between coercion and
symptoms of distress will be assessed using multiple
regression. Both the AVFGs and the narrative interviews
will be analysed using thematic narrative analysis.
Ethics and dissemination: The study has been approved
by University College Londonâs Research Ethics Committee
under Project ID Number 7335/004. Results will be
disseminated by means of peer-reviewed publications and
at national and/or international conferences
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