1,263 research outputs found
A Quantization of 2+1-Gravity Related to High-Energy Yang-Mills Theory
We point out that canonical quantization of the two-body problem in
2+1-Gravity is related to the high-energy equation in Yang-Mills theory by a
proper ordering of the relevant operators. This feature arises from expanding
the Hamiltonian around its conformal limit - or treating running coupling
effects in the Yang-Mills case - and yields a peculiar short distance behaviour
of the wave functions.Comment: 11 page
Gold nanoparticles onto cerium oxycarbonate as highly efficient catalyst for aerobic allyl alcohol oxidation
Abstract Au nanoparticles, generated by the metal vapor synthesis technique, were supported onto cerium oxycarbonate monohydrate (Ce2O(CO3)2·H2O) giving Au@Ce2O(CO3)2·H2O. The obtained heterogeneous catalyst was used in the aerobic allyl alcohol oxidation reaction performed in toluene, showing a notably higher catalytic substrate conversion and isomerization activity compared to Au onto ceria, which is the reference catalyst for this type of catalysis. Results originating from catalytic recycling experiments and PXRD, HRTEM and XPS measurements carried out on recovered Au@Ce2O(CO3)2·H2O, confirmed the stability of the catalyst under aerobic oxidation reaction conditions and hence its recyclability, without the need of a regeneration step
Characterization of natural clays from italian deposits with focus on elemental composition and exchange estimated by edx analysis: potential pharmaceutical and cosmetic uses
Purification processes performed on natural clays to select specific clay minerals are complex
and expensive and can lead to over-exploitation of some deposits. The present study aimed to examine
physicochemical (mineralogy, morphology, size, surface charge, chemical composition, cation exchange
capacity [CEC], and pH) and hydration (swelling, wettability, water sorption, and rheological behavior)
properties of three native clays from Italian deposits for potential pharmaceutical and cosmetic uses due to
the presence of phyllosilicate minerals. Particular emphasis was placed on energy dispersive X-ray (EDX)
microanalysis coupled with the ‘cesium method’ to assay clay elemental composition and CEC. One
bentonite of volcanic origin (BNT) and two kaolins, one of hydrothermal origin (K-H) and another of
lacustrine-fluvial origin (K-L), were evaluated in comparison with a commercial, purified bentonite. The
CEC assay revealed the complete substitution of exchangeable cations (Na+ and Ca2+) by Cs+ in BNT
samples and CEC values consistent with those of typical smectites (100.64 7.33 meq/100 g). For kaolins,
partial substitution of Na+ cations occurred only in the K-L samples because of the interstratified mineral
component which has small CEC values (11.13 5.46 meq/100 g for the K-H sample and 14.75
6.58 meq/100 g for the K-L sample). The degree of isomorphous substitution of Al3+ by Mg2+ affected the
hydration properties of BNT in terms of swelling, water sorption, and rheology, whereas both of the poorly
expandable kaolins exhibited significant water-adsorption properties. The EDX microanalysis has proved
to be of considerable interest in terms of providing more information about clay properties in comparison
with other commonly used methods and to identify the role played by both chemical and mineralogical
composition of natural clays for their appropriate use in pharmaceutical and cosmetic fields
Virtual Cultural Experiences: the Drivers of Satisfaction
This article presents the results of an interdisciplinary research work on the emergence and impact of virtual technologies on the valorization of cultural experience. After reviewing the literature on immersive museography and the concepts of immersion, interaction and social interaction within a cultural experience, we focus our analysis on the drivers of the users' satisfaction through a three-step research path. Firstly, we realized a preliminary qualitative overview of users' reactions to virtual environments in a series of selected cultural experiences. Secondly, we designed a model focusing on immersion and social interaction as the two potentially critical drivers of satisfaction. Thirdly, we realized a quantitative study of a project concerning an intangible cultural asset. The results of this study give evidence to the link between immersion and emotion and emphasize the essential mediating role of social interaction. These conclusions are consistent with present technological and market trends, concerning the integration of virtual reality and social networks
Effect of Dietary Chestnut or Quebracho Tannin Supplementation on Microbial Community and Fatty Acid Profile in the Rumen of Dairy Ewes
Ruminants derived products have a prominent role in diets and economy worldwide; therefore, the capability to control the rumen microbial ecosystem, for ameliorating their quality, is of fundamental importance in the livestock sector. e aim of this study was to evaluate the e ect of dietary supplementation with chestnut and quebracho tannins on microbial community and fatty acid pro le, in the rumen uid of dairy ewes. Multivariate analysis of PCR-DGGE pro les of rumen microbial communities showed a correlation among the presence of chestnut or quebracho in the diet, the speci c Butyrivibrio group DGGE pro les, the increase in 18:3 cis9, cis12, and cis15; 18:2 cis9 and cis12; 18:2 cis9 and trans11; 18:2 trans11 and cis15; and 18:1 trans11 content, and the decrease in 18:0 concentration. Phylogenetic analysis of DGGE band sequences revealed the presence of bacteria representatives related to the genera Hungatella, Ruminococcus, and Eubacterium and unclassi ed Lachnospiraceae family members, suggesting that these taxa could be a ected by tannins presence in the diets. e results of this study showed that tannins from chestnut and quebracho can reduce the biohydrogenation of unsaturated fatty acids through changes in rumen microbial communities
Gene Therapy in the Neuroendocrine System
The implementation of experimental gene therapy in animal models of neuroendocrine diseases is an area of growing interest. In the hypothalamus, restorative gene therapy has been successfully implemented in Brattleboro rats, an arginine vasopressin (AVP) mutant which suffers from diabetes insipidus, and in Koletsky (fak/fak) and in Zucker (fa/fa) rats which have leptin receptor mutations that render them obese, hyperphagic and hyperinsulinemic. In the above models, viral vectors expressing AVP, leptin receptor b and proopiomelanocortin, respectively, were stereotaxically injected in the relevant hypothalamic regions. In rats, aging brings about a progressive degeneration and loss of hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons, which are involved in the tonic inhibitory control of prolactin secretion and lactotropic cell proliferation. Stereotaxic injection of an adenoviral vector expressing insulin-like growth factor I corrected their chronic hyperprolactinemia and restored TIDA neuron numbers. Spontaneous intermediate lobe pituitary tumors in a retinoblastoma (Rb) gene mutant mouse were corrected by injection of an adenoviral vector expressing the human Rb cDNA and experimental prolactinomas in rats were partially reduced by intrapituitary injection of an adenoviral vector expressing the HSV1-thymidine kinase suicide gene. These results suggest that further implementation of gene therapy strategies in neuroendocrine models may be highly rewarding.Instituto de Investigaciones Bioquímicas de La Plat
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Lifetime measurements of 214Po and 212Po with the CTF liquid scintillator detector at LNGS
We have studied the alpha decays of 214Po into 210Pb and of 212Po into 208Pb
tagged by the coincidence with the preceding beta decays from 214Bi and 212Bi,
respectively. The employed 222Rn, 232Th, and 220Rn sources were sealed inside
quartz vials and inserted in the Counting Test Facility at the underground Gran
Sasso National Laboratory in Italy. We find that the mean lifetime of 214Po is
(236.00 +- 0.42(stat) +- 0.15(syst)) \mu s and that of 212Po is (425.1 +-
0.9(stat) +- 1.2(syst)) ns. Our results, obtained from data with
signal-to-background ratio larger than 1000, reduce the overall uncertainties
and are compatible with previous measurements.Comment: RevTex, 11 pages, 5 figures, 3 tables. This second version matches
the one accepted for publication in EPJA: minor stylistic changes plus a
discussion of calibration of TDC time scal
Colorectal cancer after bariatric surgery (Cric-Abs 2020): Sicob (Italian society of obesity surgery) endorsed national survey
Background The published colorectal cancer (CRC) outcomes after bariatric surgery (BS) are conflicting, with some anecdotal studies reporting increased risks. The present nationwide survey CRIC-ABS 2020 (Colo-Rectal Cancer Incidence-After Bariatric Surgery-2020), endorsed by the Italian Society of Obesity Surgery (SICOB), aims to report its incidence in Italy after BS, comparing the two commonest laparoscopic procedures-Sleeve Gastrectomy (SG) and Roux-en-Y gastric bypass (GBP). Methods Two online questionnaires-first having 11 questions on SG/GBP frequency with a follow-up of 5-10 years, and the second containing 15 questions on CRC incidence and management, were administered to 53 referral bariatric, high volume centers. A standardized incidence ratio (SIR-a ratio of the observed number of cases to the expected number) with 95% confidence intervals (CI) was calculated along with CRC incidence risk computation for baseline characteristics. Results Data for 20,571 patients from 34 (63%) centers between 2010 and 2015 were collected, of which 14,431 had SG (70%) and 6140 GBP (30%). 22 patients (0.10%, mean age = 53 +/- 12 years, 13 males), SG: 12 and GBP: 10, developed CRC after 4.3 +/- 2.3 years. Overall incidence was higher among males for both groups (SG: 0.15% vs 0.05%; GBP: 0.35% vs 0.09%) and the GBP cohort having slightly older patients. The right colon was most affected (n = 13) and SIR categorized/sex had fewer values < 1, except for GBP males (SIR = 1.07). Conclusion Low CRC incidence after BS at 10 years (0.10%), and no difference between procedures was seen, suggesting that BS does not trigger the neoplasm development
Serum IgG against Simian Virus 40 antigens are hampered by high levels of sHLA-G in patients affected by inflammatory neurological diseases, as multiple sclerosis
Background: Many investigators detected the simian polyomavirus SV40 footprints in human brain tumors and neurologic diseases and recently it has been indicated that SV40 seems to be associated with multiple sclerosis (MS) disease. Interestingly, SV40 interacts with human leukocyte antigen (HLA) class I molecules for cell entry. HLA class I antigens, in particular non-classical HLA-G molecules, characterized by an immune-regulatory function, are involved in MS disease, and the levels of these molecules are modified according with the disease status. Objective: We investigated in serum samples, from Italian patients affected by MS, other inflammatory diseases (OIND), non-inflammatory neurological diseases (NIND) and healthy subjects (HS), SV40-antibody and soluble sHLA-G and the association between SV40-prevalence and sHLA-G levels. Methods: ELISA tests were used for SV40-antibodies detection and sHLA-G quantitation in serum samples. Results: The presence of SV40 antibodies was observed in 6 % of patients affected by MS (N = 4/63), 10 % of OIND (N = 8/77) and 15 % of NIND (N = 9/59), which is suggestive of a lower prevalence in respect to HS (22 %, N = 18/83). MS patients are characterized by higher sHLA-G serum levels (13.9 \ub1 0.9 ng/ml; mean \ub1 St. Error) in comparison with OIND (6.7 \ub1 0.8 ng/ml), NIND (2.9 \ub1 0.4 ng/ml) and HS (2.6 \ub1 0.7 ng/ml) subjects. Interestingly, we observed an inverse correlation between SV40 antibody prevalence and sHLA-G serum levels in MS patients. Conclusion: The data obtained showed a low prevalence of SV40 antibodies in MS patients. These results seems to be due to a generalized status of inability to counteract SV40 infection via antibody production. In particular, we hypothesize that SV40 immune-inhibitory direct effect and the presence of high levels of the immune-inhibitory HLA-G molecules could co-operate in impairing B lymphocyte activation towards SV40 specific peptides
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