157 research outputs found
Nitrate isotope anomaly as a tracer of biogeochemical processes
The general aim of the thesis is testing the potential of the nitrate MIF (massindependent
fractionation) signature as a tracer of biogeochemical processes.
Nitrate ÎŽ15N, ÎŽ17O and ÎŽ18O of water samples collected at the Marano lagoon (Italy)
have been analysed, by combining the denitrifier method with the N2O thermal
decomposition in a gold furnace. No clear correlation between the magnitude of the
capital delta (Î17O=ÎŽ17O+0.5*ÎŽ18O) and the local atmospheric deposition has been
found. Moreover, sewage treatments with ozone might be responsible for some high
Î17O values associated to sampling points close to populated areas. Overall, the signal
is low (0.6â° on average, which would correspond to roughly 2% of atmospheric
nitrate in sample water) and the error associated to the measure is no less than 75%.
To test the assumption that the atmosphere is the only source of a MIF signature, a set
of nitrate minerals of different origin was analysed. The capital delta in a specimen of
buttgenbachite (with formula Cu36(NO3)2Cl8(OH)62*4â10H2O) from Likasi mine
(Congo, 4â°Â±1) and in a sample of nitromagnesite (Mg(NO3)2*6H2O) collected at
Pozalagua Cave (Spain, 10.3â°Â±0.4) would indicate the possibility that a significant
isotope anomaly could be generated due to geochemical processes.
So far the MIF in atmospheric nitrate has been interpreted as the result of chemical
reactions only, but it could be demonstrated that a series of mass dependent processes
might generate an apparent Î17O.
The study of the MIF is a relatively new field and the present work underlined some
limits of this novel tracer. Further work should be focused on identifying the systems
and the conditions for what the nitrate MIF can be considered as a conservative tracer.
Particularly, attention should be paid to the effects of biological processes involved in
the nitrogen cycle, such as nitrification and denitrification, and transport processes
Base-free Oxidative Esterification of HMF over AuPd/nNiO-TiO2. When Alloying Effects and Metal-support Interactions Converge in Producing Effective and Stable Catalysts
Furan-2,5-dimethylcarboxylate (FDMC), along with ethylene glycol (EG), is the key monomer to produce (poly-(ethylene-furanoate) (PEF). Noble metal-based catalysts can convert hydroxymethyl furfural (HMF) to FDMC in methanol through liquid phase catalytic oxidative esterification. In this work, the catalytic performance of Au, Pd and AuPd NPs supported on nanosized nickel oxide (nNiO) have been evaluated under base-free conditions at 90 degrees C and 3 bar O-2. Synergistic effects between Au and Pd imparted high activity and higher yield to FDMC compared to the monometallic counterparts. The role of support was also investigated by depositing AuPd NPs on TiO2 and nNiO-TiO2. Remarkable yield to FDMC (85 % after 8 h) and high stability were observed over AuPd/ nNiO-TiO2 catalyst. This peculiar catalytic behavior could be imputed to the formation of trimetallic AuPdNi particles offering highly active interfacial sites
Oral Health Status in Subjects with Amnestic Mild Cognitive Impairment and Alzheimer's Disease: Data from the ZabĂșt Aging Project
Background: The relationship between Alzheimer's disease (AD) and periodontitis has been recently investigated with heterogenous results.
Objective: This study aims to evaluate the oral health status and its relationship with cognitive impairment of participants, enrolled in the ZabĂșt Aging Project, a community-based cohort study performed in rural community in Sicily, Italy.
Methods: A case-control study (20 subjects with AD, 20 with amnestic mild cognitive impairment (aMCI), and 20 controls) was conducted. The protocol included a comprehensive medical and cognitive-behavioral examination. Full-mouth evaluation, microbial analysis of subgingival plaque samples (by RT-PCR analysis), and oral health-related quality of life (OHR-QoL) were evaluated.
Results: The decayed, missing, and filled teeth (DMFT) total score of AD subjects was significantly higher than for aMCI (p = 0.009) and controls (p = 0.001). Furthermore, the "M" component of DMFT (i.e., the number of missing teeth) was significantly higher in AD than in aMCI (p < 0.001) and controls (p < 0.001). A Poisson regression model revealed that age (p < 0.001), male gender (p = 0.001), and AD (p = 0.001) were positively correlated with DMFT. Concerning oral microbial load, the presence of Fusobacterium nucleatum was significantly higher in AD than in controls (p = 0.02), and a higher load of Treponema denticola was found in aMCI than with AD (p = 0.004). OHR-QoL scores did not differ among the groups.
Conclusion: The current research suggests that AD is associated with chronic periodontitis, which is capable of determining tooth loss due to the pathogenicity of Fusobacterium nucleatum. These data remain to be confirmed in larger population-based cohorts
Conservative Surgical Treatment of Bisphosphonate-Related Osteonecrosis of the Jaw with Er,Cr:YSGG Laser and Platelet-Rich Plasma: A Longitudinal Study
Abstract
Introduction: The management of bisphosphonate-related osteonecrosis of the jaw (BRONJ), with no evidence-based guidelines, remains controversial. We aimed to evaluate the efficiency of a conservative surgical treatment combining Er,Cr:YSGG laser and platelet-rich plasma (PRP) for the treatment of BRONJ in cancer patients.Methods:We performed a longitudinal cohort study. Inclusion criteria were (1) age 65 18 years; (2) cancer diagnosis; (3) treatment with NBP because of the underlying cancer.
Results:We consecutively recruited ten patients diagnosed with BRONJ in stage I or II. These patients underwent a surgical laser-assisted therapy together with autologous PRP. At the latest follow-up at 12 months, clinical improvement was observed in eight patients. Registration Number is IRCT20180329039159N1.
Conclusion:We could successfully manage the BRONJ utilizing this combined protocol to heal the 30% of surgically treated sites and to improve the 50% of patients' lesions clinically. Our findings suggest that a surgical approach combined with Er,Cr:YSGG laser and PRP benefit cancer patients with general health issues
Selectivity Control in Palladium-Catalyzed Alcohol Oxidation through Selective Blocking of Active Sites
Memory CD8+ T cells mediate antibacterial immunity via CCL3 activation of TNF/ROI+ phagocytes
Cytolysis, interferon Îł and tumor necrosis factor (TNF) α secretion are major effector mechanisms of memory CD8+ T cells that are believed to be required for immunological protection in vivo. By using mutants of the intracellular bacterium Listeria monocytogenes, we found that none of these effector activities is sufficient to protect against secondary infection with wild-type (WT) bacteria. We demonstrated that CCL3 derived from reactivated memory CD8+ T cells is required for efficient killing of WT bacteria. CCL3 induces a rapid TNF-α secretion by innate inflammatory mononuclear phagocytic cells (MPCs), which further promotes the production of radical oxygen intermediates (ROIs) by both MPCs and neutrophils. ROI generation is the final bactericidal mechanism involved in L. monocytogenes clearance. These results therefore uncover two levels of regulation of the antibacterial secondary protective response: (a) an antigen-dependent phase in which memory CD8+ T cells are reactivated and control the activation of the innate immune system, and (b) an antigen-independent phase in which the MPCs coordinate innate immunity and promote the bactericidal effector activities. In this context, CCL3-secreting memory CD8+ T cells are able to mediate âbystanderâ killing of an unrelated pathogen upon antigen-specific reactivation, a mechanism that may be important for the design of therapeutic vaccines
Growth and Osteogenic Differentiation of Discarded Gingiva-Derived Mesenchymal Stem Cells on a Commercial Scaffold
Background: In periodontal patients with jawbone resorption, the autologous bone graft is considered a âgold standardâ procedure for the placing of dental prosthesis; however, this procedure is a costly intervention and poses the risk of clinical complications. Thanks to the use of adult mesenchymal stem cells, smart biomaterials, and active biomolecules, regenerative medicine and bone tissue engineering represent
a valid alternative to the traditional procedures.
Aims: In the past, mesenchymal stem cells isolated from periodontally compromised gingiva were considered a biological waste and discarded during surgical procedures.
Conclusion: Matriderm represents a biocompatible scaffold able to support the in vitro cell growth and osteodifferentiation ability of gingival mesenchymal stem cells isolated from waste gingiva, and could be employed to develop low-cost and painless strategy of autologous bone tissue regeneration. This study aims to test the osteoconductive activity of FISIOGRAFT Bone Granular and Matriderm collagen scaffolds on mesenchymal stem cells isolated from periodontally compromised gingiva as a low-cost and painless strategy of autologous bone tissue regeneration.
Materials and Methods: We isolated human mesenchymal stem cells from 22 healthy and 26 periodontally compromised gingival biopsy tissues and confirmed the stem cell phenotype by doubling time assay, colony-forming unit assay, and expression of surface
and nuclear mesenchymal stem cell markers, respectively by cytofluorimetry and realtime quantitative PCR. Healthy and periodontally compromised gingival mesenchymal stem cells were seeded on FISIOGRAFT Bone GranularR and MatridermR scaffolds, and in vitro cell viability and bone differentiation were then evaluated.
Results: Even though preliminary, the results demonstrate that FISIOGRAFT Bone GranularR is not suitable for in vitro growth and osteogenic differentiation of healthy and periodontally compromised mesenchymal stem cells, which, instead, are able to grow, homogeneously distribute, and bone differentiate in the MatridermR collagen scaffold
Assessing the nonequilibrium thermodynamics in a quenched quantum many-body system via single projective measurements
The authors are indebted to T. S. Batalhao, J. Goold,
R. Serra, and Peter Talkner for invaluable discussions.We analyze the nature of the statistics of the work done on or by a quantum many-body system brought
out of equilibrium. We show that, for the sudden quench and for an initial state that commutes with the
initial Hamiltonian, it is possible to retrieve the whole nonequilibrium thermodynamics via single
projective measurements of observables. We highlight, in a physically clear way, the qualitative
implications for the statistics of work coming from considering processes described by operators that
either commute or do not commute with the unperturbed Hamiltonian of a given system. We consider a
quantum many-body system and derive an expression that allows us to give a physical interpretation, for a
thermal initial state, to all of the cumulants of the work in the case of quenched operators commuting with
the unperturbed Hamiltonian. In the commuting case, the observables that we need to measure have an
intuitive physical meaning. Conversely, in the noncommuting case, we show that, although it is possible to
operate fully within the single-measurement framework irrespectively of the size of the quench, some
difficulties are faced in providing a clear-cut physical interpretation to the cumulants. This circumstance
makes the study of the physics of the system nontrivial and highlights the nonintuitive phenomenology of
the emergence of thermodynamics from the fully quantum microscopic description. We illustrate our ideas
with the example of the Ising model in a transverse field showing the interesting behavior of the high-order
statistical moments of the work distribution for a generic thermal state and linking them to the critical
nature of the model itself.This work has been supported by a PERFEST grant
(L. F.) from Universita degli Studi di Palermo, the Marie
Curie Action, the UK EPSRC (EP/G004579/1 and EP/
L005026/1), the John Templeton Foundation (Grant ID
43467), the EU Collaborative Project TherMiQ (Grant
Agreement No. 618074), and by a Marie Curie Intra
European Fellowship within the 7th European
Community Framework Programme through the project
NeQuFlux Grant No. 623085 (M. C.). T. J. G. A. is
supported by the European Commission, the European
Social Fund, and the Region Calabria through the
program POR Calabria FSE 2007-2013-Asse IV
Capitale Umano-Obiettivo Operativo M2. A. X. acknowledges
funding from the Royal Commission for the
Exhibition of 1851. Part of this work was supported by the COST Action MP1209 âThermodynamics in the Quantum Regime.âpeer-reviewe
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