217 research outputs found
PULSED GRADIENT FIELD STUDY OF NANOSIZED RHENIUM COMPLEXES
Radiopharmaceuticals incorporating 99mTc and 186/188Re have been extensively studied in the last decades [1]. Suitable nuclear properties of these metals can be exploited for both diagnosis (99mTc) and therapy (186/188Re). Among the different fragments introduced into the radiopharmaceuticals, great interest has gained the aquo complex [M(H2O)3(CO)3]+ (M = Re, Tc), that contains three labile water molecules together with a stable fac M(CO)3+ core, suitable for bio-conjugation. To test the feasibility and stability of the bioconjugates, experiments are normally performed using the cold rhenium natural isotopic mixture as surrogate. Different chelating agents as well as different coordination routes have been proposed in order to get rhenium derivatives with high specificity and stability [2].
In this communication we show the results obtained by reacting [Re(H2O)3(CO)3]+ with highly hydrosoluble polymers, suitable for the use as biomedical materials.
A detailed study on the polymer size, in the presence and in the absence of rhenium, has been performed by means of longitudinal relaxation (T1) times and pulsed gradient spin echo (PGSE) NMR experiments [3].
1H PGSE NMR experiments have been performed at room temperature on diluted sample, at different ionic strength and different pH, to evaluate the influence of these parameters on polymer aggregations. Stimulated echo sequences, incorporating bipolar gradient pulses, were used, both with and without water suppression. Through these methods, diffusion coefficients have been determined and the hydrodynamic radii rH of the random polymers, with and without rhenium, have been estimated.
Comparison with results obtained by dynamic light scattering measurements will be provided.
References
[1] See for instance U. Mazzi and M. Riondato Recent development in Bioinorganic Chemistry 1-33 (2006)
[2] See for instance R. Alberto, R. Schibli, R. Waibel, U. Abram and A. P. Schubiger Coord. Chem. Rev. 190-192, 901-919 (1999)
[3] See for instance A. Macchioni, G. Ciancaleoni, C. Zuccaccia and D. Zuccaccia Chem. Soc. Rev. 37, 479-489 (2008
1H, 19F, and 15N NMR study of the interaction between bis(pentafluorophenyl)borinic acid and nitrogen bases
Bis(pentafluorophenyl)borinic acid ((ArF)2BOH, ArF = C6F5, 1) is a molecule that, due to its multiple reactivity, can behave in different and not always straightforward ways in the presence of nucleophiles. It has been already shown its behaviour in dicloromethane solution in the presence of water, THF and methanol. Briefly, it exists as monomer and trimer (1m and 1t, see Chart 1), and the presence of nucleophiles strongly influence the thermodynamic and the kinetic of the monomer-trimer interconversion. Moreover, according to the nature of the nucleophile, 1 shows a camaleonic nature by forming several, sometimes unexpected, species.2,3 We have studied now the reaction of 1 in the presence of nitrogen bases, that can act as Lewis and Br\uf8nsted bases. Two nitrogen bases were studied, namely 1,8-bis(dimethylamino)naphthalene (DMAN), which can act as Br\uf8nsted base only, and pyridine, which is a good Lewis base but weak Br\uf8nsted base. First of all, the Br\uf8nsted base DMAN has been proved to be more efficient than oxygenated Lewis bases in catalyzing the trimerization process. Indeed it is enough a catalytic amount of base to cause the complete trimerization of 1. The so obtained trimeric deprotonated anion 2 (Chart 2) is unstable with respect to dearylation reactions, leading eventually (in the presence of more than 0.33 equiv of DMAN and at higher temperatures) to the tetrarylic species 3 (Chart 2). On the other hand, the behaviour of pyridine is quite different, since 0.33 equiv of base are requested to complete the trimerization of 1, and also in this case the obtained trimer is anionic. Moreover, the presence of 1 equivalent of pyridine does not cause the dearylation process but gives rise to the monomeric neutral 1:1 adduct 4 (Chart 2).
Both the identification and the characterization of the involved species were performed by multiparametric and multinuclear low temperature NMR spectroscopy
1H NMR Characterization of Organic and Inorganic Nanoparticles
Drug delivery employing nano-object as liposomes, polymer conjugates, and nanoparticles suspended in solution is a subject of high current interest [1]. The characterization of the size and the surface functionalization of these nanoparticles is of primary importance. Microscopy techniques give information on deposited colloidal samples, after solvent evaporation, so that the correspondence with the nature of the species in solution is not granted. Dynamic Light Scattering (DLS), which is usually used to estimate the size of a colloidal sample in solution, can overestimate the radii of very small nanoparticles [2]. Diffusion NMR, and in particular Pulsed gradient spin-echo (PGSE) technique, has recently emerged as a valuable tool for colloids characterization [3], complementary to DLS from the point of view of the size evaluation, being highly reliable for the measurement of the smallest particles. Moreover, NMR provide information not only on the size, but also on the interaction between the capping ligands and the nanoparticle surface. In this work, we present the characterization through 1H PGSE NMR measurements of the size of spherical and rod-like TiO2/oleic acid nanoparticles and of conjugates between Re complexes and polyamidoamine nanoparticles. Moreover, by 1H NMR experiments the interaction between TiO2 and the capping oleic acid (OA) has been characterized.
[1] a) A. H. Faraji, P. Wipf, Bioorganic and Medicinal Chemistry 2009, 17, 2950-2962; b) S. M. Garg, A. V. Deshmukh, Nano Science and Nano Technology 2007, 1(2), 45-58; c) C. Khemtong, C. W. Kessinger, J. Gao, Chem. Commun. 2009, 3497-3510.
[2] C. Sanna, C. La Mesa, L. Mannina, P. Stano, S. Viel, A. Segre, Langmuir 2006, 22, 6031-6041.
[3] a) F. Ribot, V. Escax, C. Roiland, C. Sanchez, J. C. Martins, M. Biesemans, I. Verbruggen, R. Willem, Chem. Commun. 2005, 1019-1021; b) M. Valentini, A. Vaccaro, A. Rehor, A. Napoli, J. A. Hubbell, N. Tirelli, J. Am. Chem. Soc. 2004, 126, 2142-2147
Morning Priming Exercise Strategy to Enhance Afternoon Performance in Young Elite Soccer Players.
PURPOSE: To compare the effects of different modalities of morning priming exercise on afternoon physical performance with the associated hormonal and psychophysiological responses in young soccer players. METHODS: In a randomized counterbalanced crossover design, 12 young soccer players completed 3 different morning conditions on 3 different days: repeated-sprint running (6 × 40 m), easy exercise (4 × 12 fast half squats, 6 speed ladder drills, and 20-m sprints), and control (no exercise). Blood testosterone and cortisol concentrations were assessed upon arrival (approximately 8:30AM) and approximately 5 hours and 30 minutes later. Body temperature, self-reported mood, quadriceps neuromuscular function (maximal voluntary contraction, voluntary activation, rate of torque development, and twitch contractile properties), jump, and sprint performance were evaluated twice per day, while rating of perceived exertion, motivation, and the Yo-Yo Intermittent Recovery level 2 (IR2) tests were assessed once per day. RESULTS: Compared with the control, repeated-sprint running induced a possible positive effect on testosterone (+11.6%) but a possible to very likely negative effect on twitch contractile properties (-13.0%), jump height (-1.4%), and Yo-Yo IR2 (-7.1%). On the other hand, easy exercise had an unclear effect on testosterone (-3.3%), resulted in lower self-reported fatigue (-31.0%) and cortisol (-12.9%), and had a possible positive effect on the rate of torque development (+4.3%) and Yo-Yo IR2 (+6.5%) compared with the control. CONCLUSIONS: Players' testosterone levels were positively influenced by repeated-sprint running, but this did not translate into better physical function, as both muscular and endurance performance were reduced. Easy exercise seemed to be suitable to optimize the physical performance and psychophysiological state of young soccer players
Clinical audit of minimally invasive nonsurgical techniques in active periodontal therapy
Aims: Periodontitis is one of the most widespread diseases worldwide. Many efforts have been made to increase the efficacy of periodontitis therapy as much as possible. Recently, minimally invasive nonsurgical techniques (MINST) were introduced in the periodontal field as an alternative to minimally invasive surgical techniques (MIST). This clinical audit aims to evaluate the results of MINST in the initial phase of treatment for periodontitis. Materials and methods: One hundred seven patients with periodontitis who were treated with MINST between 2013 and 2017 and reevaluated after 2 months were included in this clinical audit. The primary outcome analyzed was the proportion of pocket closure. The secondary outcomes were tooth extraction before active periodontal therapy, full-mouth plaque score (FMPS) change, full-mouth bleeding score (FMBS) change, average probing pocket depth (PPD) reduction, and average clinical attachment level (CAL) gain between the baseline and reevaluation values. Results: A total of 2,407 teeth were included in the analysis. At the patient level, the treatment resulted in a mean pocket closure rate of 71.6 ± 15.7% for sites with an initial PPD ≥5 mm. The treatment was statistically significantly (p < 0.001) more effective with respect to the primary outcome compared with expected values reported in a recent meta-analysis (57%). The subgroup analysis revealed statistically significant differences between single and multirooted teeth and between shallow (5-6 mm) and deep pockets (≥7 mm) at the baseline. Conclusion: Nonsurgical periodontal therapy with MINST achieved satisfactory results that were better than expected based on the scientific literature. Single-rooted and shallow pockets showed the best proportion of pocket closure at the reevaluation after treatment. Clinical significance: Minimally invasive nonsurgical techniques can be the treatment of choice when approaching periodontally diseased patients with nonsurgical periodontal therapy
Aggregation and ionization equilibria of bis(pentafluorophenyl)borinic acid driven by hydrogen-bonding with tetrahydrofuran
Bis(pentafluophenyl)borinic acid, Ar2BOH (1, Ar = C6F5), in dichloromethane solution is present as an equilibrium mixture of monomeric (1m) and trimeric (1t) forms. Previous studies showed that water affects both the position and the rate of this equilibrium. Here, the behavior of 1 in the presence of tetrahydrofuran (THF), a nucleophile able to behave as a Lewis base and H-bond acceptor only, has been studied, by monitoring with H-1 and F-19 NMR the course of titrations performed directly into NMR tubes. The addition, at 183 K, of 0.33 equiv of THF caused the instantaneous and quantitative formation of the hydrogen-bonded adduct between the trimer 1t and one molecule of THF. Homo- and heteronuclear 2D NMR correlation experiments led to a solution structure consistent with the C2-optimized geometry obtained by PM3 computations. The H-bonding of the THF molecule causes major deformations of the molecular geometry of the trimer, so that only one molecule of THF can interact with the trimer, in spite of its three OH groups. Intra- and intermolecular exchange processes involving this adduct have been investigated by 2D EXSY experiments, showing flopping of the cycle conformation, rotation of the aromatic rings around their B-C bonds, and exchange of THF among the three OH groups, in addition to the exchange between free 1t and the adduct. When the amount of added THF was higher than 0.33 equiv, an unexpected ionization process occurred, leading to the cation [Ar2B(OH2)2]+ and to deprotonated 1t, i.e., to the anion [Ar6B3O3H2]- of Cs symmetry. On increasing the temperature, progressive partial fragmentation of the trimeric species was observed. Both B-11 NMR evidence and PM3 computations indicated that, at variance with what is observed in the interaction with H2O, the interaction between THF and 1m occurs preferentially via an H-bonded adduct, Ar2BO-H...THF, rather than a Lewis acid-base complex, Ar2B(OH)(THF). This confirms the poor Lewis acidity of the boron atom of 1m
Diagnostic performance and cell count of EBUS–TBNA needle gauges: a prospective trial
Background. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a well-established diagnostic procedure for evaluating hilar and mediastinal lymphadenopathies and is the gold standard for lung cancer diagnosis and staging. Recent studies assessed the effectiveness of the 19-G flex needle in obtaining larger EBUS-TBNA samples, and prospective small series gave similar results in terms of diagnostic yield when testing different gauge needles. The lack of homogeneity between series and the small sample size of some prospective cohorts poses a limit to the validity of those results. This prospective controlled study compared the 19-G flex and 22-G needles in terms of diagnostic yield. An objective laboratory method was used to count cells and compare the two needles’ cytologic yields. Material. A prospective controlled study was conducted on 90 patients undergoing EBUS-TBNA for the diagnosis of hilar and mediastinal lymphadenopathies. The institutional ethic committee (IEO573) approved the study, and informed consent was obtained from all patients. Results. A total of 90 patients were enrolled in this study, 84.4% of whom were diagnosed with malignancy and 15.6% with non-neoplastic disease. Sensitivity for malignancy was 93.4% (CI: 87.4–97.1%) for the 19-G needle and 92.6% (CI: 86.3–96.5%) for the 22-G needle (p = 0.80). The percentage of malignant cells in the cell block was 63.9% and 61.5% for the 22-G and 19-G needles, respectively. The cell count assessed by flow cytometry was 2071 cells/μL (IQR: 600,2265) with the 22-G needle and 2761 cells/μL (IQR: 505,3250) with the 19-G needle (p = 0.79). The malignant cell count was 0.05 × 103 cells/μL with the 22-G and 0.08 × 103 cells/μL with the 19-G needle (p = 0.70). There was no difference in the presence of tissue cores in the samples, and rapid on-site evaluation (ROSE) cellularity was comparable between the two needles. Conclusions. The 19-G flex EBUS-TBNA needle is comparable to the 22-G needle in terms of diagnostic yield for cyto-histological evaluation of hilar and mediastinal lymphadenopathies. There is no difference between the 19-G and 22-G needle cell counts evaluated by flow cytometry
Science and technology of BOREXINO: A Real time detector for low-energy solar neutrinos: A Real Time Detector for Low Energy Solar Neutrinos
BOREXINO, a real-time device for low energy neutrino spectroscopy is nearing completion of construction in the underground laboratories at Gran Sasso, Italy (LNGS). The experiment's goal is the direct measurement of the flux of 7Be solar neutrinos of all flavors via neutrino-electron scattering in an ultra-pure scintillation liquid. Seeded by a series of innovations which were brought to fruition by large scale operation of a 4-ton test detector at LNGS, a new technology has been developed for BOREXINO. It enables sub-MeV solar neutrino spectroscopy for the first time. This paper describes the design of BOREXINO, the various facilities essential to its operation, its spectroscopic and background suppression capabilities and a prognosis of the impact of its results towards resolving the solar neutrino problem. BOREXINO will also address several other frontier questions in particle physics, astrophysics and geophysics
Endobronchial Ultrasound Transbronchial Needle Aspiration In Thoracic Diseases: Much More Than Mediastinal Staging
Background and Objective. EBUS-TBNA has revolutionized the diagnostic approach to thoracic diseases from a surgical to minimally invasive procedure. In non small-cell lung cancer (NCSLC) patients, EBUS-TBNA is able to dictate the consecutive therapy both for early and advanced stages, providing pathological diagnosis, mediastinal staging, and even adequate specimens for molecular analysis. This study reports on the ability of EBUS-TBNA to make different diagnoses and dictates the consecutive therapy in a large cohort of patients presenting different thoracic diseases. Methods. All procedures performed from January 2012 to September 2016 were reviewed. Five groups of patients were created according to the main indications for the procedure. Group 1: lung cancer staging; Group 2: pathological diagnosis in advanced stage lung cancer; Group 3: lymphadenopathy in previous malignancies; Group 4: pulmonary lesions; Group 5: unknown origin lymphadenopathy. In each group, the diagnostic yield of the procedure was analysed. Non malignant diagnosis at EBUS-TBNA was confirmed by a surgical procedure or clinical and radiological follow-up. Results. 1891 patients were included in the analysis. Sensitivity, negative predictive value, and diagnostic accuracy in each group were 90.7%, 79.4%, and 93.1% in Group 1; 98.5%, 50%, and 98.5% in Group 2; 92.4%, 85.1%, and 94.7% in Group 3; 90.9%, 51.0%, and 91.7% in Group 4; and 25%, 83.3%, and 84.2% in Group 5. Overall sensitivity, negative predictive value, and accuracy were 91.7%, 78.5%, and 93.6%, respectively. Conclusions. EBUS-TBNA is the best approach for invasive mediastinal investigation, confirming its strategic role and high accuracy in thoracic oncology
La hora del museo: la sala Uriburu del Museo Histórico y Colonial de la Provincia de Buenos Aires (Luján, 1932)
El artículo analiza el proceso de creación de la Sala Uriburu del Museo Histórico y Colonial de la Provincia de Buenos Aires instalado en la ciudad de Luján y abierto al público en 1923. La sala fue inaugurada el 4 de septiembre de 1932 y estaba destinada a honrar la memoria del líder de la "Revolución" del 6 de septiembre de 1930. El objetivo es dar cuenta de los múltiples factores que incidieron en su instalación considerando que ella no puede explicarse solamente a través de la relación directa entre coyuntura política, atmósfera nacionalista y la necesidad de crear un mito para perpetuar su memoria. Proponemos entonces explorar las prácticas y dispositivos colectivos indispensables en el proceso de creación de evidencias materiales para sustentar la visualización de un relato histórico.O artigo analisa o processo de instalação da Sala Uriburu, do Museu Histórico e Colonial da Província de Buenos Aires, fundado na cidade de Luján e aberto ao público em 1923. A sala foi inaugurada em 4 de setembro de 1932, e destinava-se a "honrar a memória" do líder da "Revolução" de 6 de setembro de 1930, poucos meses depois de sua morte. O objetivo é dar conta dos múltiplos fatores que incidiram na instalação, considerando que ela não pode ser explicada somente através da relação direta entre conjuntura política, atmosfera nacionalista e a necessidade de criar um mito para perpetuar sua memória. Propomos, então, explorar as práticas e dispositivos coletivos indispensáveis no processo de criação de evidências materiais para sustentar a visualização de um relato histórico.This article analyzes the installation of Uriburu's Hall at the Museo Histórico y Colonial de la Provincia de Buenos Aires, institution established in Luján in 1923. This hall was opened to the public in September 1932, to celebrate the name and memory of the hero of the Revolution of 1930. Far from proposing a direct relationship between politics and museum displays, this article wants to display the several elements that colluded in the creation of this hall
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