207 research outputs found

    Dispersed fluorsecence spectroscopy of jet-cooled AgAu and Pt?

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    Journal ArticleDispersed fluorescence spectroscopy has been used to study jet-cooled AgAu and Pt2 . Fluorescence resulting from the excitation of five bands of the A?X 1?+ system of AgAu was dispersed, and 51 measured ground state vibrational levels were fit to provide ground state vibrational constants of ?"e=198.2260.11 cm21 and ?"exe"=0.512?0.002 cm-1. A Franck?Condon calculation was performed using the experimental values of the ground and excited state vibrational frequencies and anharmonicities, providing an estimate of the change in bond length upon excitation of the A?X system of ?re=0.214?0.005 ?. Fluorescence resulting from four different excitations of Pt2 was dispersed, providing vibrational constants for the ground and two low-lying excited states. Ground state vibrational constants of ?e=222.3 cm-1 and ?exe=0.62 cm21 were obtained, based on the analysis of 16 measured ground state vibrational levels. In addition, a low-lying excited state was located at T0=2877 cm-1, with ?e=197 cm-1. This state perturbed the ground state, from which it was deduced that it has the same symmetry as the ground state. A comparison to theoretical calculations suggests that both states have 0g 1 symmetry. Finally, a metastable state of Pt2 lying at an unknown energy was determined to have ?e=211 cm-1, ?exe=0.4 cm-1

    Dispersed fluorsecence spectroscopy of AINi, NiAu, and PtCu

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    Journal ArticleDispersed fluorescence studies of AlNi, NiAu, and PtCu have been performed, providing spectroscopic information about the ground and low-lying excited electronic states. Vibrational frequencies are reported for the ground X 2?5/2 state of all three molecules. In the case of AlNi, fluorescence to all five of the states originating from the 3dNi 9 3sAl2?2 manifold has been observed. For both NiAu and PtCu, fluorescence to two low-lying excited states in addition to the ground state was observed. Relative energies, vibrational constants, and, when possible, V values of these states are reported. Comparisons of the measured electronic states to the predictions of a ligand-field plus spin?orbit model are also provided, along with a comparison of the electronic structure of PtCu to that of PtH

    Evaluation of a Cell-Free Collagen Type I-Based Scaffold for Articular Cartilage Regeneration in an Orthotopic Rat Model.

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    The management of chondral defects represents a big challenge because of the limited self-healing capacity of cartilage. Many approaches in this field obtained partial satisfactory results. Cartilage tissue engineering, combining innovative scaffolds and stem cells from different sources, emerges as a promising strategy for cartilage regeneration. The aim of this study was to evaluate the capability of a cell-free collagen I-based scaffold to promote cartilaginous repair after orthotopic implantation in vivo. Articular cartilage lesions (ACL) were created at the femoropatellar groove in rat knees and cell free collagen I-based scaffolds (S) were then implanted into right knee defect for the ACL-S group. No scaffold was implanted for the ACL group. At 4-, 8- and 16-weeks post-transplantation, degrees of cartilage repair were evaluated by morphological, histochemical and gene expression analyses. Histological analysis shows the formation of fibrous tissue, at 4-weeks replaced by a tissue resembling the calcified one at 16-weeks in the ACL group. In the ACL-S group, progressive replacement of the scaffold with the newly formed cartilage-like tissue is shown, as confirmed by Alcian Blue staining. Immunohistochemical and quantitative real-time PCR (qRT-PCR) analyses display the expression of typical cartilage markers, such as collagen type I and II (ColI and ColII), Aggrecan and Sox9. The results of this study display that the collagen I-based scaffold is highly biocompatible and able to recruit host cells from the surrounding joint tissues to promote cartilaginous repair of articular defects, suggesting its use as a potential approach for cartilage tissue regeneration

    Molecular screening for bacterial pathogens in ticks (Ixodes ricinus) collected on migratory birds captured in northern Italy

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    Migratory birds have an important role in transporting ticks and associated tick-borne pathogens over long distances. In this study, 2,793 migratory birds were captured by nets in a ringing station, located in northern Italy, and checked for the presence of ticks. Two-hundred and fifty-one ticks were identified as nymphs and larvae of Ixodes ricinus (Linnaeus, 1758) and they were PCR-screened for the presence of bacteria belonging to Borrelia burgdorferi sensu lato, Rickettsia spp., Francisella tularensis and Coxiella burnetii. Four species of Borrelia (B. garinii, B. afzelii, B. valaisiana and B. lusitaniae) and three species of Rickettsia (R. monacensis, R. helvetica and Candidatus Rickettsia mendelii) were detected in 74 (30%) and 25 (10%) respectively out of 251 ticks examined. Co-infection with Borrelia spp. and Rickettsia spp. in the same tick sample was encountered in 7 (7%) out of the 99 infected ticks. We report for the first time the presence of Candidatus Rickettsia mendelii in I. ricinus collected on birds in Italy. This study, besides confirming the role of birds in dispersal of I. ricinus, highlights an important route by which tick-borne pathogens might spread across different countries and from natural environments towards urbanised areas

    Effects of Bariatric Surgery on COVID-19: a Multicentric Study from a High Incidence Area

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    Introduction: The favorable effects of bariatric surgery (BS) on overall pulmonary function and obesity-related comorbidities could influence SARS-CoV-2 clinical expression. This has been investigated comparing COVID-19 incidence and clinical course between a cohort of patients submitted to BS and a cohort of candidates for BS during the spring outbreak in Italy. Materials and Methods: From April to August 2020, 594 patients from 6 major bariatric centers in Emilia-Romagna were administered an 87-item telephonic questionnaire. Demographics, COVID-19 incidence, suggestive symptoms, and clinical outcome parameters of operated patients and candidates to BS were compared. The incidence of symptomatic COVID-19 was assessed including the clinical definition of probable case, according to World Health Organization criteria. Results: Three hundred fifty-three operated patients (Op) and 169 candidates for BS (C) were finally included in the statistical analysis. While COVID-19 incidence confirmed by laboratory tests was similar in the two groups (5.7% vs 5.9%), lower incidence of most of COVID-19-related symptoms, such as anosmia (p: 0.046), dysgeusia (p: 0.049), fever with rapid onset (p: 0.046) were recorded among Op patients, resulting in a lower rate of probable cases (14.4% vs 23.7%; p: 0.009). Hospitalization was more frequent in C patients (2.4% vs 0.3%, p: 0.02). One death in each group was reported (0.3% vs 0.6%). Previous pneumonia and malignancies resulted to be associated with symptomatic COVID-19 at univariate and multivariate analysis. Conclusion: Patients submitted to BS seem to develop less severe SARS-CoV-2 infection than subjects suffering from obesity

    Microenvironmental regulation of the IL-23R/IL-23 axis overrides chronic lymphocytic leukemia indolence

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    Although the progression of chronic lymphocytic leukemia (CLL) requires the cooperation of the microenvironment, the exact cellular and molecular mechanisms involved are still unclear. We investigated the interleukin (IL)-23 receptor (IL-23R)/IL-23 axis and found that circulating cells from early-stage CLL patients with shorter time-to-treatment, but not of those with a more benign course, expressed a defective form of the IL-23R complex lacking the IL-12R beta 1 chain. However, cells from both patient groups expressed the complete IL-23R complex in tissue infiltrates and could be induced to express the IL-12R. 1 chain when cocultured with activated T cells or CD40L(+) cells. CLL cells activated in vitro in this context produced IL-23, a finding that, together with the presence of IL-23 in CLL lymphoid tissues, suggests the existence of an autocrine/paracrine loop inducing CLL cell proliferation. Interference with the IL-23R/IL-23 axis using an anti-IL-23p19 antibody proved effective in controlling disease onset and expansion in xenografted mice, suggesting potential therapeutic strategies

    Prevalence of Bartonella henselae and Bartonella clarridgeiae in cats in the south of Brazil: a molecular study

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    Bartonella spp are the causative agent of cat scratch disease in humans. Cats are the natural reservoir of these bacteria and may infect humans through scratches, bites or fleas. Blood samples from 47 cats aged up to 12 months were collected for this study. All animals were lodged in municipal animal shelters in the Vale do Sinos region, Rio Grande do Sul, Brazil. Bartonella spp were detected by genus-specific polymerase chain reaction (PCR) and when the PCR was positive, the species were determined by DNA sequencing. A Giemsa-stained blood smear was also examined for the presence of intraerythrocytic elements suggestive of Bartonella spp infection. Phylogenetic analysis was also performed for all positive samples. Using molecular detection methods, Bartonella spp were detected in 17.02% (8/47) of the samples. In seven out of eight samples confirmed to be positive for Bartonella spp, blood smear examination revealed the presence of intraerythrocytic elements suggestive of Bartonella spp. Phylogenetic analysis characterized positive samples as Bartonella henselae (5) or Bartonella clarridgeiae (3). To the best of our knowledge, this is the first molecular study demonstrating the presence of Bartonella spp in cats from the Southern Region of Brazil
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