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1.
J Stomatol Oral Maxillofac Surg ; : 101899, 2024 Apr 29.
Article in English | MEDLINE | ID: mdl-38692455

ABSTRACT

In patients with cleft lip and palate the most common associated dental problem is lateral incisor agenesis, often associated with lack of support and definition of the nasal tip. In many cases, adhesions deriving from surgical procedures and skeletal discrepancy make orthognathic surgery and rhinoseptoplasty unavoidable. In the present case report a dental rehabilitation with canine substitution and prosthetic-implant treatment in a posterior area is described. The use, during rhinoseptoplasty, of a customized titanium prosthesis, which provides projection for the tip of the nose, is also introduced. The patient was administered two questionnaires in order to assess the psychological aspects related to the cleft outcomes and the influence that the treatment conveyed.

2.
Dental Press J Orthod ; 28(1): e2321124, 2023.
Article in English | MEDLINE | ID: mdl-37075415

ABSTRACT

INTRODUCTION: Although the superiority of clear aligners over multi-bracket appliances in keeping gingiva healthy has been suggested, the possible benefits of one aligner design over another have not yet been investigated, especially with regard to the vestibular edge. OBJECTIVE: The aim of this study was to measure several periodontal indexes in adolescents undergoing orthodontic treatment with aligners, comparing two different types of rim. METHODS: The study involved 43 patients aged between 14 and 18 years. The periodontal health was assessed using plaque index (PI), gingival index (GI), and gingival bleeding index (GBI), at the start of the treatment with aligners (T0), with a vestibular rim (VR) reaching up to 3 mm beyond the gingival margin. Three months later (T1), aligners were set to obtain a juxtagingival rim (JR) on the second quadrant and VR on the first quadrant. The periodontal indexes were measured again, both at T1 and then three months later (T2). RESULTS: Intra-quadrant comparisons revealed a statistically significant worsening of the periodontal indexes only for the second quadrant (p<0.05), at T1 (GI), and especially at T2 (PI, GI, GBI), while no statistically significant changes were found for the first quadrant. CONCLUSIONS: More severe mechanical irritation, especially during insertion and removal of the aligner, can explain the worsening inflammatory indexes with the JR. In addition, the pressure exerted by the JR on the gingival sulcus seemed to facilitate plaque deposition, whereas the VR had a protective effect, reducing the risk of mechanical trauma.


Subject(s)
Dental Plaque , Gingiva , Adolescent , Humans , Dental Plaque Index
3.
Nat Biotechnol ; 41(4): 552-559, 2023 04.
Article in English | MEDLINE | ID: mdl-36217028

ABSTRACT

The formation of macromolecular complexes can be measured by detection of changes in rotational mobility using time-resolved fluorescence anisotropy. However, this method is limited to relatively small molecules (~0.1-30 kDa), excluding the majority of the human proteome and its complexes. We describe selective time-resolved anisotropy with reversibly switchable states (STARSS), which overcomes this limitation and extends the observable mass range by more than three orders of magnitude. STARSS is based on long-lived reversible molecular transitions of switchable fluorescent proteins to resolve the relatively slow rotational diffusivity of large complexes. We used STARSS to probe the rotational mobility of several molecular complexes in cells, including chromatin, the retroviral Gag lattice and activity-regulated cytoskeleton-associated protein oligomers. Because STARSS can probe arbitrarily large structures, it is generally applicable to the entire human proteome.


Subject(s)
Proteome , Humans , Fluorescence Polarization/methods , Spectrometry, Fluorescence/methods
4.
Dental press j. orthod. (Impr.) ; 28(1): e2321124, 2023. tab, graf
Article in English | LILACS-Express | LILACS, BBO - Dentistry | ID: biblio-1430269

ABSTRACT

ABSTRACT Introduction: Although the superiority of clear aligners over multi-bracket appliances in keeping gingiva healthy has been suggested, the possible benefits of one aligner design over another have not yet been investigated, especially with regard to the vestibular edge. Objective: The aim of this study was to measure several periodontal indexes in adolescents undergoing orthodontic treatment with aligners, comparing two different types of rim. Methods: The study involved 43 patients aged between 14 and 18 years. The periodontal health was assessed using plaque index (PI), gingival index (GI), and gingival bleeding index (GBI), at the start of the treatment with aligners (T0), with a vestibular rim (VR) reaching up to 3 mm beyond the gingival margin. Three months later (T1), aligners were set to obtain a juxtagingival rim (JR) on the second quadrant and VR on the first quadrant. The periodontal indexes were measured again, both at T1 and then three months later (T2). Results: Intra-quadrant comparisons revealed a statistically significant worsening of the periodontal indexes only for the second quadrant (p<0.05), at T1 (GI), and especially at T2 (PI, GI, GBI), while no statistically significant changes were found for the first quadrant. Conclusions: More severe mechanical irritation, especially during insertion and removal of the aligner, can explain the worsening inflammatory indexes with the JR. In addition, the pressure exerted by the JR on the gingival sulcus seemed to facilitate plaque deposition, whereas the VR had a protective effect, reducing the risk of mechanical trauma.


RESUMO Introdução: Embora se alegue uma superioridade dos alinhadores transparentes sobre os aparelhos multibraquetes em manter a gengiva saudável, ainda não foram investigados os possíveis benefícios de um modelo de alinhador sobre outro, especialmente no que diz respeito à borda vestibular. Objetivo: O objetivo deste estudo foi medir vários índices periodontais em adolescentes submetidos a tratamento ortodôntico com alinhadores, comparando dois tipos diferentes de borda. Métodos: O estudo envolveu 43 pacientes com idade entre 14 e 18 anos. A saúde periodontal foi avaliada por meio do índice de placa (IP), índice gengival (IG) e índice de sangramento gengival (ISG), ao início do tratamento com alinhadores (T0), com borda vestibular (BV) estendendo-se até 3 mm além da margem gengival. Três meses depois (T1), os alinhadores foram ajustados para se obter uma borda justagengival (BJ) no segundo quadrante e BV no primeiro quadrante. Os índices periodontais foram medidos novamente tanto em T1 quanto três meses depois (T2). Resultados: As comparações intraquadrantes revelaram uma piora estatisticamente significativa nos índices periodontais apenas para o segundo quadrante (p<0,05), em T1 (IG) e especialmente em T2 (IP, IG, ISG), enquanto nenhuma mudança estatisticamente significativa foi encontrada para o primeiro quadrante. Conclusões: Irritações mecânicas mais intensas, principalmente durante a inserção e remoção do alinhador, podem explicar a piora dos índices inflamatórios com a BJ. Além disso, a pressão exercida pela BJ no sulco gengival pareceu facilitar a deposição de placa, enquanto a BV teve um efeito protetor, reduzindo o risco de trauma mecânico.

5.
Materials (Basel) ; 14(24)2021 Dec 18.
Article in English | MEDLINE | ID: mdl-34947444

ABSTRACT

The polymer structure of thermoplastic materials currently used to make aligners is altered by the oral conditions and this negatively affects their capacity to move teeth. This study aimed to compare different options for storing aligners when not in use by superimposing successive 3D images to identify which storage method least affects material shape and weight. Fifty PET-G aligners, produced using the CA Digital method, were divided into four groups (1A, 1B, 1C, and 2D) and were stored for 18 h a day in artificial saliva at 37 °C. Then, to mimic their storage conditions when not in use, aligners in group 1A were immersed for the remaining 8 hours a day in bicarbonate solution, those in group 1B in chlorhexidine solution, those in group 1C in distilled water, and those in group 2D were stored dry. The samples were scanned at the baseline (before the immersion cycles began) and again two weeks later. The digital scans were superimposed and the median deformation, its variability, and weight differences were recorded for each group. Statistical analysis showed aligner deformation (expansion) in all three groups stored in wet conditions, with a statistically significant difference between groups 1A and 1C. Aligners in group 2D shrank slightly, and to a significantly greater degree with respect to group 1C. Variability in the degree of deformation was similar among the three groups stored in wet conditions, but significantly greater in group 2D. Weight gains were recorded in all four groups, the smallest in group 2D and the largest in group 1A. Storing aligners in dry conditions promoted lower deformation in the material, involving a slight shrinkage, whereas wet storage conditions caused an expansion of the aligner, especially when distilled water is used.

6.
Dent J (Basel) ; 9(4)2021 Apr 19.
Article in English | MEDLINE | ID: mdl-33921608

ABSTRACT

Background: Pregnancy is a unique moment in a woman's life, accompanied with several physiologic changes that have an impact on oral health. Aim of the study: The purpose of the present study was to conduct a critical review of published literature regarding pregnancy and dentistry, the most frequent oral diseases that are encountered during pregnancy, their correlation to adverse pregnancy events, and safe dental treatments that can be performed during pregnancy. Methods: A Medline/COCHRANE search was carried using specific keywords and MeSH terms, combined with the boolean operators "OR" and "AND". Results: The search led to 146 publications including guidelines, meta-analyses, systematic and non-systematic reviews, published between 2000 and 2021. Discussion and conclusions: Due to the increased inflammatory and immune body response that characterizes pregnancy, periodontal conditions are often aggravated during pregnancy and periodontal disease encountered frequently in pregnant patients. There are conflicting study results in the literature regarding the association between periodontitis and adverse pregnancy outcomes. Periodontal treatment did not show a significant reduction in the adverse outcomes. Many dentists, often due to lack of information, are reluctant to provide dental treatment to pregnant women. However, preventive and restorative dental treatment is safe during pregnancy. Diagnostic radiographs may be performed after the first trimester if absolutely necessary. Analgesics (such as paracetamol) and anesthetics (such as lidocaine) are also considered safe. In case of infection, antibacterial drugs such as amoxicillin, ampicillin, and some cephalosporines and macrolides can also be prescribed. Organogenesis takes place in the first trimester, the time during which the fetus is susceptible to severe malformations (teratogenesis). The ideal time to perform dental treatment is the second trimester (week 17 to 28). However, acute pain or infections make the intervention of the dentist absolutely necessary and emergency treatment can be performed during the whole pregnancy period.

7.
J Phys Chem Lett ; 11(19): 7972-7980, 2020 Oct 01.
Article in English | MEDLINE | ID: mdl-32886518

ABSTRACT

The biological light-harvesting process offers an unlimited source of inspiration. The high level of control, adaptation capability, and efficiency challenge humankind to create artificial biomimicking nanoarchitectures with the same performances to respond to our energy needs. Here, in the extensive search for design principles at the base of efficient artificial light harvesters, an approach based on self-assembly of pigment-peptide conjugates is proposed. The solvent-driven and controlled aggregation of the peptide moieties promotes the formation of a dense network of interacting pigments, giving rise to an excitonic network characterized by intense and spectrally wide absorption bands. The ultrafast dynamics of the nanosystems studied through two-dimensional electronic spectroscopy reveals that the excitation energy is funneled in an ultrafast time range (hundreds of femtoseconds) to a manifold of long-living dark states, thus suggesting the considerable potentiality of the systems as efficient harvesters.


Subject(s)
Biomimetic Materials/chemistry , Light-Harvesting Protein Complexes/chemistry , Nanostructures/chemistry , Peptides/chemistry , Photosensitizing Agents/chemistry , Porphyrins/chemistry , Amino Acid Sequence , Kinetics , Light , Molecular Conformation , Molecular Dynamics Simulation , Spectrometry, Fluorescence
8.
BMJ Open Respir Res ; 7(1)2020 03.
Article in English | MEDLINE | ID: mdl-32238349

ABSTRACT

Patients with asthma and Chronic Obstructive Respiratory Disease (COPD) rely on three main device classes for inhalation therapy: metered-dose inhalers (MDIs), dry powder inhalers (DPIs) and soft-mist inhalers (SMIs). The carbon footprint (CF) of these inhalers differs with MDIs having a higher impact than DPIs and SMIs due to the propellant in MDIs. However, the certified CF of specific MDI products may differ significantly. MDIs still represent an essential option for many patients. Consequently, novel approaches shall be considered to balance environmental goals with patient health and well-being while maintaining a diverse range of choices for patients and physicians.


Subject(s)
Asthma/drug therapy , Carbon Footprint , Nebulizers and Vaporizers , Precision Medicine/methods , Pulmonary Disease, Chronic Obstructive/drug therapy , Administration, Inhalation , Adrenergic beta-Agonists/administration & dosage , Humans
9.
Dental Press J Orthod ; 24(1): 38e1-37e7, 2019.
Article in English | MEDLINE | ID: mdl-30916255

ABSTRACT

OBJECTIVE: The aim of the study was to verify and compare the accuracy of full-arch digital impressions obtained using two intraoral scanners and three scanning methodologies. METHODS: A resin model created with dental 3-D printing was scanned by a reference scanner (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) in order to obtain a 3D reference; the same resin model was then scanned with two different intraoral scanners (Zfx IntraScan and Carestream 3600 - CS 3600®, Carestream, Rochester, NY, USA) using: Technique A (from tooth #27 up to tooth #17); Technique B (from tooth #11 up to tooth #17 and then from tooth #21 up to tooth #27) and Technique C (from tooth #22 up to tooth #17, and then from tooth #12 up to tooth #27 - the MeshLab software v. 1.3.3 was then used to match the two scans). The scans obtained were superimposed over the reference scan by means of a software, and the volumetric discrepancies were calculated. RESULTS: The mean results for the Zfx Intrascan scanner were: Technique A = 302.47 ± 37.42 µm; Technique B = 180.45 ± 29.86 µm; Technique C = 147.34 ± 28.23 µm. The mean results for the Carestream 3600 scanner were: Technique A = 303.59 ± 40.20 µm; Technique B = 181.53 ± 29.61 µm; Technique C = 142.28 ± 35.33 µm. Technique C, used by both scanners, produced less volumetric discrepancies compared to the other techniques. CONCLUSIONS: The scanning technique had a statistically significant effect on the quality of the scan (p< 0.0001), whereas the scanner did not present any significant influence (p= 0.91).


Subject(s)
Dental Arch , Imaging, Three-Dimensional , Models, Dental , Printing, Three-Dimensional , Computer-Aided Design , Dental Impression Technique , Humans , Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Software
10.
Opt Express ; 27(3): 2975-2987, 2019 Feb 04.
Article in English | MEDLINE | ID: mdl-30732326

ABSTRACT

The analysis of quantum beats in time-resolved spectroscopic signals is becoming a task of primary importance because it is now clear that they bring crucial information about chemical reactivity, transport, and relaxation processes. Here we describe how to exploit the wide family of time-frequency transform methodologies to obtain information not only about the frequency but also about the dynamics of the oscillating components contributing to the overall beating signal. Several linear and bilinear transforms have been considered, and a general and easy procedure to judge in a non-arbitrary way the performances of different transforms has been outlined.

11.
Dental press j. orthod. (Impr.) ; 24(1): 38e1-37e7, Jan.-Feb. 2019. graf
Article in English | LILACS | ID: biblio-989689

ABSTRACT

ABSTRACT Objective: The aim of the study was to verify and compare the accuracy of full-arch digital impressions obtained using two intraoral scanners and three scanning methodologies. Methods: A resin model created with dental 3-D printing was scanned by a reference scanner (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) in order to obtain a 3D reference; the same resin model was then scanned with two different intraoral scanners (Zfx IntraScan and Carestream 3600 - CS 3600®, Carestream, Rochester, NY, USA) using: Technique A (from tooth #27 up to tooth #17); Technique B (from tooth #11 up to tooth #17 and then from tooth #21 up to tooth #27) and Technique C (from tooth #22 up to tooth #17, and then from tooth #12 up to tooth #27 - the MeshLab software v. 1.3.3 was then used to match the two scans). The scans obtained were superimposed over the reference scan by means of a software, and the volumetric discrepancies were calculated. Results: The mean results for the Zfx Intrascan scanner were: Technique A = 302.47 ± 37.42 µm; Technique B = 180.45 ± 29.86 µm; Technique C = 147.34 ± 28.23 µm. The mean results for the Carestream 3600 scanner were: Technique A = 303.59 ± 40.20 µm; Technique B = 181.53 ± 29.61 µm; Technique C = 142.28 ± 35.33 µm. Technique C, used by both scanners, produced less volumetric discrepancies compared to the other techniques. Conclusions: The scanning technique had a statistically significant effect on the quality of the scan (p< 0.0001), whereas the scanner did not present any significant influence (p= 0.91).


RESUMO Objetivo: o objetivo do presente estudo foi verificar e comparar a precisão de modelos digitais de uma arcada dentária completa obtidos utilizando-se dois tipos de scanners e três metodologias de digitalização. Métodos: um modelo de resina feito com impressão 3D foi digitalizado em um scanner de referência (Zfx Evolution - Zimmer Biomet, Palm Beach Gardens, FL) para se obter uma referência em 3D; o mesmo modelo de resina foi, então, digitalizado com dois scanners intrabucais diferentes (Zfx IntraScan e Carestream 3600 - CS 3600®, Carestream, Rochester, NY, EUA) utilizando: Técnica A (do dente #27 ao dente #17); Técnica B (do dente #11 ao dente #17 e, em seguida, do dente #21 ao dente #27); e Técnica C (do dente #22 ao dente #17 e, em seguida, do dente #12 ao dente #27 - osoftware MeshLab v. 1.3.3 foi, então, usado para mesclar as duas leituras). Em seguida, as imagens digitalizadas foram sobrepostas à imagem de referência, utilizando-se um software, e as discrepâncias volumétricas foram calculadas. Resultados: a média dos resultados para o scanner Zfx Intrascan foram: Técnica A = 302,47 ± 37,42 µm; Técnica B = 180,45 ± 29,86 µm; Técnica C = 147,34 ± 28,23 µm. A média dos resultados para o scanner Carestream 3600 foram: Técnica A= 303,59 ± 40,20 µm; Técnica B = 181,53 ± 29,61 µm; Técnica C = 142,28 ± 35,33 µm. A Técnica C, utilizada em ambos os scanners, produziu as menores discrepâncias volumétricas, quando comparada às outras técnicas. Conclusões: a técnica de digitalização teve um efeito estatisticamente significativo sobre a qualidade do modelo digital (p< 0,0001), enquanto o tipo de scanner usado não apresentou qualquer influência significativa (p= 0,91).


Subject(s)
Humans , Imaging, Three-Dimensional/methods , Dental Arch , Models, Dental , Printing, Three-Dimensional , Image Processing, Computer-Assisted/methods , Software , Dental Impression Technique , Computer-Aided Design
13.
Nat Commun ; 9(1): 3160, 2018 08 08.
Article in English | MEDLINE | ID: mdl-30089871

ABSTRACT

The subtle details of the mechanism of energy flow from carotenoids to chlorophylls in biological light-harvesting complexes are still not fully understood, especially in the ultrafast regime. Here we focus on the antenna complex peridinin-chlorophyll a-protein (PCP), known for its remarkable efficiency of excitation energy transfer from carotenoids-peridinins-to chlorophylls. PCP solutions are studied by means of 2D electronic spectroscopy in different experimental conditions. Together with a global kinetic analysis and multiscale quantum chemical calculations, these data allow us to comprehensively address the contribution of the potential pathways of energy flow in PCP. These data support dominant energy transfer from peridinin S2 to chlorophyll Qy state via an ultrafast coherent mechanism. The coherent superposition of the two states is functional to drive population to the final acceptor state, adding an important piece of information in the quest for connections between coherent phenomena and biological functions.


Subject(s)
Carotenoids/chemistry , Chlorophyll/chemistry , Energy Transfer , Light-Harvesting Protein Complexes/chemistry , Protozoan Proteins/chemistry , Biophysical Phenomena , Carotenoids/metabolism , Chlorophyll/metabolism , Computer Simulation , Dinoflagellida/chemistry , Kinetics , Light-Harvesting Protein Complexes/metabolism , Models, Molecular , Protozoan Proteins/metabolism , Spectrum Analysis
14.
Phys Chem Chem Phys ; 20(27): 18176-18183, 2018 Jul 11.
Article in English | MEDLINE | ID: mdl-29961782

ABSTRACT

Although the harnessing of multiple and hot excitons is a prerequisite for many of the groundbreaking applications of semiconductor quantum dots (QDs), the characterization of their dynamics through conventional spectroscopic techniques is cumbersome. Here, we show how a careful analysis of 2DES maps acquired in different configurations (BOXCARS and pump-probe geometry) allows the tracking and visualization of intraband Auger relaxation mechanisms, driving the hot carrier cooling, and interband bi- and tri-exciton recombination dynamics. The results obtained on archetypal core-shell CdSe/ZnS QDs suggest that, given the global analysis of the resulting datasets, 2D electronic spectroscopy techniques can successfully and efficiently dispel the intertwined dynamics of fast and ultrafast recombination processes in nanomaterials. Hence, we propose this analysis scheme to be used in future research on novel quantum confined systems.

15.
J Phys Chem Lett ; 9(5): 1079-1085, 2018 Mar 01.
Article in English | MEDLINE | ID: mdl-29446639

ABSTRACT

In this work, we demonstrate the use of two-dimensional electronic spectroscopy (2DES) to study the mechanism and time scale of the femtosecond Stokes shift dynamics in molecules characterized by intramolecular charge transfer, such as distyryl-functionalized boron dipyrromethene (BODIPY) molecules. The obtained results demonstrate that 2DES allows clear and direct visualization of the phenomenon. The analysis of the 2D data in terms of 2D frequency-frequency decay associated maps provides indeed not only the time scale of the relaxation process but also the starting and the final point of the energy flow and the associated reorganization energy, identified by looking at the coordinates of a negative signature below the diagonal. The sensitivity of the 2DES technique to vibrational coherence dynamics also allowed the identification of a possible relaxation mechanism involving specific interaction between a vibrational mode of the dye and the solvent.

16.
Sci Rep ; 7(1): 11389, 2017 09 12.
Article in English | MEDLINE | ID: mdl-28900171

ABSTRACT

The non-radiative relaxation of the excitation energy from higher energy states to the lowest energy state in chlorophylls is a crucial preliminary step for the process of photosynthesis. Despite the continuous theoretical and experimental efforts to clarify the ultrafast dynamics of this process, it still represents the object of an intense investigation because the ultrafast timescale and the congestion of the involved states makes its characterization particularly challenging. Here we exploit 2D electronic spectroscopy and recently developed data analysis tools to provide more detailed insights into the mechanism of internal conversion within the Q-bands of chlorophyll a. The measurements confirmed the timescale of the overall internal conversion rate (170 fs) and captured the presence of a previously unidentified ultrafast (40 fs) intermediate step, involving vibronic levels of the lowest excited state.


Subject(s)
Chlorophyll A/chemistry , Mechanical Phenomena , Energy Transfer , Photosynthesis , Spectrum Analysis , Spinacia oleracea/chemistry
17.
Opt Express ; 24(21): 24773-24785, 2016 Oct 17.
Article in English | MEDLINE | ID: mdl-27828197

ABSTRACT

2D electronic spectroscopy is a widely exploited tool to study excited state dynamics. A high density of information is enclosed in 2D spectra. A crucial challenge is to objectively disentangle all the features of the third order optical signal. We propose a global analysis method based on the variable projection algorithm, which is able to reproduce simultaneously coherence and population dynamics of rephasing and non-rephasing contributions. Test measures at room temperature on a standard dye are used to validate the procedure and to discuss the advantages of the proposed methodology with respect to the currently employed analysis procedures.

18.
Phys Chem Chem Phys ; 18(4): 3086-96, 2016 Jan 28.
Article in English | MEDLINE | ID: mdl-26741055

ABSTRACT

The monosaccharide L-rhamnose is common in bacterial polysaccharides and the disaccharide α-L-Rhap-α-(1 → 2)-α-L-Rhap-OMe represents a structural model for a part of Shigella flexneri O-antigen polysaccharides. Utilization of [1'-(13)C]-site-specific labeling in the anomeric position at the glycosidic linkage between the two sugar residues facilitated the determination of transglycosidic NMR (3)JCH and (3)JCC coupling constants. Based on these spin-spin couplings the major state and the conformational distribution could be determined with respect to the ψ torsion angle, which changed between water and dimethyl sulfoxide (DMSO) as solvents, a finding mirrored by molecular dynamics (MD) simulations with explicit solvent molecules. The (13)C NMR spin relaxation parameters T1, T2, and heteronuclear NOE of the probe were measured for the disaccharide in DMSO-d6 at two magnetic field strengths, with standard deviations ≤1%. The combination of MD simulation and a stochastic description based on the diffusive chain model resulted in excellent agreement between calculated and experimentally observed (13)C relaxation parameters, with an average error of <2%. The coupling between the global reorientation of the molecule and the local motion of the spin probe is deemed essential if reproduction of NMR relaxation parameters should succeed, since decoupling of the two modes of motion results in significantly worse agreement. Calculation of (13)C relaxation parameters based on the correlation functions obtained directly from the MD simulation of the solute molecule in DMSO as solvent showed satisfactory agreement with errors on the order of 10% or less.


Subject(s)
Dimethyl Sulfoxide/chemistry , Glycosides/chemistry , Carbon-13 Magnetic Resonance Spectroscopy , Molecular Conformation , Molecular Dynamics Simulation , Stochastic Processes
19.
Opt Express ; 23(15): 20040-50, 2015 Jul 27.
Article in English | MEDLINE | ID: mdl-26367662

ABSTRACT

Time-frequency decomposition techniques, borrowed from the signal-processing field, have been adapted and applied to the analysis of 2D oscillating signals. While the Fourier-analysis techniques available so far are able to interpret the information content of the oscillating signal only in terms of its frequency components, the time-frequency transforms (TFT) proposed in this work can instead provide simultaneously frequency and time resolution, unveiling the dynamics of the relevant beating components, and supplying a valuable help in their interpretation. In order to fully exploit the potentiality of this method, several TFTs have been tested in the analysis of sample 2D data. Possible artifacts and sources of misinterpretation have been identified and discussed.

20.
J Magn Reson ; 246: 94-103, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25117152

ABSTRACT

The analysis of NMR relaxation data is revisited along the lines of a Bayesian approach. Using a Markov Chain Monte Carlo strategy of data fitting, we investigate conditions under which relaxation data can be effectively interpreted in terms of internal dynamics. The limitations to the extraction of kinetic parameters that characterize internal dynamics are analyzed, and we show that extracting characteristic time scales shorter than a few tens of ps is very unlikely. However, using MCMC methods, reliable estimates of the marginal probability distributions and estimators (average, standard deviations, etc.) can still be obtained for subsets of the model parameters. Thus, unlike more conventional strategies of data analysis, the method avoids a model selection process. In addition, it indicates what information may be extracted from the data, but also what cannot.


Subject(s)
Algorithms , Data Interpretation, Statistical , Magnetic Resonance Spectroscopy/methods , Markov Chains , Models, Statistical , Monte Carlo Method , Computer Simulation , Pattern Recognition, Automated/methods , Reproducibility of Results , Sensitivity and Specificity
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