495 research outputs found
Preliminary study for small animal preclinical hadrontherapy facility
Aim of this work is the study of the preliminary steps to perform a particle treatment of cancer cells inoculated in small animals and to realize a preclinical hadrontherapy facility. A well-defined dosimetric protocol was developed to explicate the steps needed in order to perform a precise proton irradiation in small animals and achieve a highly conformal dose into the target. A precise homemade positioning and holding system for small animals was designed and developed at INFN-LNS in Catania (Italy), where an accurate Monte Carlo simulation was developed, using Geant4 code to simulate the treatment in order to choose the best animal position and perform accurately all the necessary dosimetric evaluations. The Geant4 application can also be used to realize dosimetric studies and its peculiarity consists in the possibility to introduce the real target composition in the simulation using the DICOM micro-CT image. This application was fully validated comparing the results with the experimental measurements. The latter ones were performed at the CATANA (Centro di AdroTerapia e Applicazioni Nucleari Avanzate) facility at INFN-LNS by irradiating both PMMA and water solid phantom. Dosimetric measurements were performed using previously calibrated EBT3 Gafchromic films as a detector and the results were compared with the Geant4 simulation ones. In particular, two different types of dosimetric studies were performed: the first one involved irradiation of a phantom made up of water solid slabs where a layer of EBT3 was alternated with two different slabs in a sandwich configuration, in order to validate the dosimetric distribution. The second one involved irradiation of a PMMA phantom made up of a half hemisphere and some PMMA slabs in order to simulate a subcutaneous tumour configuration, normally used in preclinical studies. In order to evaluate the accordance between experimental and simulation results, two different statistical tests were made: Kolmogorov test and gamma index test. This work represents the first step towards the realization of a preclinical hadrontherapy facility at INFN-LNS in Catania for the future in vivo studies
Prognostic role of endocarditis in isolated tricuspid valve surgery. A propensity-weighted study
Objectives: The role of the underlying etiology in isolated tricuspid valve surgery has not been investigated extensively in current literature. Aim of this study was to analyse outcomes of patients undergoing surgery due to endocarditis compared to other pathologies.
Methods: The SURTRI study is a multicenter study enrolling adult patients who underwent isolated tricuspid valve surgery (n = 406, 55 ± 16 y.o.; 56% female) at 13 international sites. Propensity weighted analysis was performed to compare groups (IE group n = 107 vs Not-IE group n = 299).
Results: No difference was found regarding the 30-day mortality (Group IE: 2.8% vs Group Not-IE = 6.8%; OR = 0.45) and major adverse events. Weighted cumulative incidence of cardiac death was significantly higher for patients with endocarditis (p = 0.01). The composite endpoint of cardiac death and reoperation at 6 years was reduced in the Group IE (63.2 ± 6.8% vs 78.9 ± 3.1%; p = 0.022). Repair strategy resulted in an increased late survival even in IE cases.
Conclusions: Data from SURTRI study report acceptable 30-day results but significantly reduced late survival in the setting of endocarditis of the tricuspid valve. Multi-disciplinary approach, repair strategy and earlier treatment may improve outcomes.
Keywords: Endocarditis; Isolated tricuspid valve disease; Tricuspid valve
Bat diversity boosts ecosystem services:Evidence from pine processionary moth predation
HighlightsâąUnveiled new PPM bat predators, emphasizing bats' pest suppression roleâąCluttered and open space foragers: bat guilds with high pest consumption potentialâąBat abundance, species richness and bat diet richness link with pest consumption.âąDiverse bat communities enhance pest consumption, reinforcing biotic resistance.âąNiche segregation fosters bat coexistence, enhancing ecosystem stabilityAbstractConiferous forests contribute to the European economy; however, they have experienced a decline since the late 1990s due to an invasive pest known as the pine processionary moth, Thaumetopoea pityocampa. The impacts of this pest are increasingly exacerbated by climate change. Traditional control strategies involving pesticides have had negative effects on public health and the environment. Instead, forest managers seek a more ecological and sustainable approach to management that promotes the natural actions of pest control agents. This study aims to evaluate the role of bats in suppressing pine processionary moths in pine forests and examine how the bat community composition and abundance influence pest consumption. Bats were sampled in the mountainous environment of the Serra da Estrela in central Portugal to collect faecal samples for DNA meta-barcoding analysis. We assessed the relationship between a) bat richness, b) bat relative abundance, c) bat diet richness, and the frequency of pine processionary moth consumption. Our findings indicate that sites with the highest bat species richness and abundance exhibit the highest levels of pine processionary moth consumption. The intensity of pine processionary moth consumption is independent of insect diversity within the site. The highest occurrence of pine processionary moth presence in bat diets is primarily observed in species that forage in cluttered habitats. A typical predator of pine processionary moths among bats is likely to be a forest-dwelling species that specialises in consuming Lepidoptera. These species primarily use short-range echolocation calls, which are relatively inaudible to tympanate moths, suitable for locating prey in cluttered environments, employing a gleaning hunting strategy. Examples include species from the genera Plecotus, Myotis, and Rhinolophus. This study enhances our understanding of the potential pest consumption services provided by bats in pine forests. The insights gained from this research can inform integrated pest management practices in forestry
Indications for Digital Monitoring of Patients With Multiple Nevi: Recommendations from the International Dermoscopy Society
Introduction: In patients with multiple nevi, sequential imaging using total body skin photography (TBSP) coupled with digital dermoscopy (DD) documentation reduces unnecessary excisions and improves the early detection of melanoma. Correct patient selection is essential for optimizing the efficacy of this diagnostic approach.
Objectives: The purpose of the study was to identify, via expert consensus, the best indications for TBSP and DD follow-up.
Methods: This study was performed on behalf of the International Dermoscopy Society (IDS). We attained consensus by using an e-Delphi methodology. The panel of participants included international experts in dermoscopy. In each Delphi round, experts were asked to select from a list of indications for TBSP and DD.
Results: Expert consensus was attained after 3 rounds of Delphi. Participants considered a total nevus count of 60 or more nevi or the presence of a CDKN2A mutation sufficient to refer the patient for digital monitoring. Â Patients with more than 40 nevi were only considered an indication in case of personal history of melanoma or red hair and/or a MC1R mutation or history of organ transplantation.
Conclusions: Our recommendations support clinicians in choosing appropriate follow-up regimens for patients with multiple nevi and in applying the time-consuming procedure of sequential imaging more efficiently. Further studies and real-life data are needed to confirm the usefulness of this list of indications in clinical practice
Partition function of N = 2* SYM on a large four-sphere
We examine the partition function of N=2* supersymmetric SU(N) Yang-Mills theory on the four-sphere in the large radius limit. We point out that the large radius partition function, at fixed N, is computed by saddle points lying on particular walls of marginal stability on the Coulomb branch of the theory on R^4. For N an even (odd) integer and \theta_YM=0, (\pi), these include a point of maximal degeneration of the Donagi-Witten curve to a torus where BPS dyons with electric charge [N/2] become massless. We argue that the dyon singularity is the lone saddle point in the SU(2) theory, while for SU(N) with N>2, we characterize potentially competing saddle points by obtaining the relations between the Seiberg-Witten periods at such points. Using Nekrasov's instanton partition function, we solve for the maximally degenerate saddle point and obtain its free energy as a function of g_YM and N, and show that the results are "large-N exact". In the large-N theory our results provide analytical expressions for the periods/eigenvalues at the maximally degenerate saddle point, precisely matching previously known formulae following from the correspondence between N=2* theory and the elliptic Calogero-Moser integrable model. The maximally singular point ceases to be a saddle point of the partition function above a critical value of the coupling, in agreement with the recent findings of Russo and Zarembo
Non-hexagonal neural dynamics in vowel space
Are the grid cells discovered in rodents relevant to human cognition? Following up on two seminal studies by others, we aimed to check whether an approximate 6-fold, grid-like symmetry shows up in the cortical activity of humans who "navigate" between vowels, given that vowel space can be approximated with a continuous trapezoidal 2D manifold, spanned by the first and second formant frequencies. We created 30 vowel trajectories in the assumedly flat central portion of the trapezoid. Each of these trajectories had a duration of 240 milliseconds, with a steady start and end point on the perimeter of a "wheel". We hypothesized that if the neural representation of this "box" is similar to that of rodent grid units, there should be an at least partial hexagonal (6-fold) symmetry in the EEG response of participants who navigate it. We have not found any dominant n-fold symmetry, however, but instead, using PCAs, we find indications that the vowel representation may reflect phonetic features, as positioned on the vowel manifold. The suggestion, therefore, is that vowels are encoded in relation to their salient sensory-perceptual variables, and are not assigned to arbitrary gridlike abstract maps. Finally, we explored the relationship between the first PCA eigenvector and putative vowel attractors for native Italian speakers, who served as the subjects in our study
ARTERIAL HYPERTENSION AND SOCIAL LONELINESS IN AN OLDER POPULATION FROM 55 YEARS AND OLDER. BARQUISIMETO, VENEZUELA
Social loneliness has been shown to be closely related to the health status of the population. The present research assessed the prevalence of arterial hypertension and its association with the perception of social loneliness in residents over 55 years of age in the Antonio Carrillo community. In this regard, an analytical prevalence study, 92 people were studied as population, the previous diagnosis of arterial hypertension was asked, blood pressure was measured, and the data collection tool ESTE II was subsequently applied. It was found that, in the population over 55 years of age, according to the general characteristics of the population, the female sex predominated (63%); in addition, the majority of the habitants were between the ages of 55 and 64 (52.2%); according to marital status, married residents prevailed (41.3%); with regard to education, the majority of the population underwent incomplete primary education (24%) and in regards of the inactivity by the unemployment situation (76.1%). 65.2 % of the population was found to be hypertensive, and in terms of the perception of social loneliness, 68.5% of the population was found to have the same conditions. As in fact, when the association between blood pressure and the perception of social loneliness was made, it was specified that 68.3% of the habitants with perception of social loneliness were hypertensive (p>0.05)
Approaches in biotechnological applications of natural polymers
Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento CientfĂico e TecnolĂłgico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de NvĂel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)
Measurement Invariance of the Meaning in Life Questionnaire Across 17 Countries
The Meaning in Life Questionnaire assesses presence of and search for meaning in life. Although the questionnaire has shown promising psychometric properties in samples from different countries, the scaleâs measurement invariance across a large number of nations has yet to be assessed. This study is aimed at addressing this gap, providing insight into how meaning in life is constructed and experienced across countries and into the extent to which cross-country comparisons can be made. A total of 3867 adult participants from 17 countries, aged 30â60, balanced by gender, and with at least secondary education, completed the questionnaire as part of the Eudaimonic and Hedonic Happiness Investigation. Single sample confirmatory factor analysis, multigroup confirmatory factor analysis, and alignment optimization were applied to investigate the scaleâs performance across the samples. Good psychometric properties and high levels of approximate measurement invariance emerged for the Presence subscale after removal of item 9, the only reverse-phrased item. Performance of the Search subscale varied more across samples, suggesting caution in interpreting related results supporting approximate measurement invariance. The conceptualization of presence of meaning operationalized in the corresponding subscale (without item 9) appears consistent across countries, whereas search for meaning seems to be less universally homogenous and requires further exploration. Moreover, the Meaning in Life Questionnaire does not reflect the conceptual distinction between âpurposeâ and âmeaningâ currently acknowledged by researchers. This issue should be further explored in studies addressing the scaleâs performance across cultures
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