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  • Author: S. F. Bruno x
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Five Lectures

Abstract

Synthetic NaGaSi2O6-pyroxene, space group C2/c, was investigated at low temperature between 295 to 110 K by X-ray diffraction. The evolution of the unit-cell parameters as a function of temperature does not indicate any structural phase transition down to 110 K. Calculated values for the Debye temperature, θD, and the Grüneisen parameter, γ, are 653(39) and 0.84(8) K, respectively, close to those of other pyroxenes. Five complete intensity data collections were performed at 295, 235, 190, 145, and 110 K to investigate the temperature dependence of the crystal structure. The space group remains C2/c down to 110 K, but anomalies were found between 235 and 190 K for the temperature dependencies of the volume and strain of the M1 polyhedron. This anomalous behavior could be related to variations of the Ga-O2(C1,D1) bond length and the O1(A1,B1)-Ga-O2(C1,D1) bond angle. The C2/c-P1̅ phase transition observed in a previous work for NaTiSi2O6 at about 200 K did not occur for NaGaSi2O6 down to the minimum temperature investigated in this work. This is not due to the different ionic radius at M1 site or to a different tetrahedral chain extension between these two compositions but it is likely due to unfilled t2g orbitals, which do not exist in NaGaSi2O6.

Abstract

Background: Urolithiasis is a common disease that is increasing throughout the world. This study aimed at determining the composition of urinary stones in patients with renal lithiasis in an emerging country.

Methods: A morphological analysis was performed on 340 urinary stones from 325 consecutive patients from Brazil with lithiasis.

Results and conclusions: Among the 340 stones analyzed, 34.7% were pure. The most frequent stone was calcium oxalate (CaOx) (59.3%), followed by uric acid (23.7%). CaOx was more frequently seen in women (p=0.024), while uric acid was more common in men (p<0.001). Among the mixed stones, CaOx (67.1%) was the most frequent major component, followed by carbapatite (11.2%) and struvite (7.9%). CaOx (p<0.001) and uric acid (p=0.014) were more frequently the major components in men, while carbapatite (p<0.001) and struvite (p=0.011) were more frequent in women. The major component of both pure and mixed stones was CaOx (65.1%), followed by uric acid (10.9%), carbapatite (10%), struvite (6.7%), ammonium urate (5.1%), cystine (1.8%) and protein (0.4%). These findings may be related to regional factors, such as weather and nutritional habits.

Clin Chem Lab Med 2009;47:561–4.

Abstract

The crystal structures of the neutral dmt compounds, 4,5-bis(methylthiolato)-1,2-dithiole-3-thione, (1), 4-benzoylthiolato-5-methylthiolato-1,2-dithiole-3-thione, (3) and 4-benzoylthiolato-5-benzylthiolato-1,2-dithiole-3-thione, (4), and the organic salt, 3,4,5-tris(methylthiolato)-1,2-dithiolium iodide (2) have been determined at 120 K. The packing of the molecules provides a variety of intermolecular, or interion, contacts. Notable features in 1 and 3 are the columns of overlapping dithiole rings. In both cases the columns are propagated in the direction of b and neighbouring rings are related to one another by the operation of crystallographic centres of symmetry. In 2 weak C–H · · · I (H · · · I = 3.0236 and 3.0166 Å) and C–H · · · S (H · · · S = 2.8660 Å) hydrogen-bonds, contacts with short I · · · S distances (3.433 and 3.370 Å) and a C–H · · · π contact, with the dithiole ring as acceptor (H · · · Cg = 2.946 Å), create zig-zag chains propagated in the direction of b which are further connected to form corrugated sheets parallel to (0 0 1) with methyl groups on their surfaces. Intermolecular O · · · Sthiole contacts much shorter than the sum of the contact radii (3.32 Å) of oxygen and sulphur are present in 3 and 4.The formation of 3 or 4 occurred regiospecifically from successive reactions of 4,5-bis(benzoylthiolato)-1,2-dithiole-3-thione with one equivalent of caesium hydroxide and RI (R = Me or PhCH2).

Abstract

Seven new compounds have been synthetized in satisfactory yields (51-78 %) through the treatment of mesoionic 1,3-thiazolium-5-thiolate (4a-d) and 1,3,4-thiadiazolium- 5-thiolate (10a,b) with chloroacetic acid or methyl iodide: 1,3,4-thiadiazolium-5-methylthio- (11) and 5-thioacetate (12). The structure of the title compounds was elucidated by elemental analysis, IR, 1H and 13C NMR spectroscopy. The newly synthesized compounds 5a, 6a, 11 and 12 were evaluated for their ex vivo spasmolytic potential on four isolated smooth muscles (rat aorta and uterus, guinea pig ileum and trachea) and compared with scopolamine. Some of the compounds exhibited potent spasmolytic activity equal to or stronger than scopolamine

Abstract

Judo is a high-intensity intermittent combat sport which causes cardiac adaptations both morphologically and related to the autonomic nervous system (ANS). Therefore, this study aims to verify the correlation between heart rate variability (HRV) at rest with performance in the Special Judo Fitness Test (SJFT) and whether groups with different RR values at rest show different performance in the SJFT and during post-test recovery. Sixteen judo athletes with 7.2 ± 3.9 years of training experience participated in the study. Before and after the SJFT execution HRV and lactate measurements were conducted. For HRV analysis, we used the mean interval RR, the standard deviation of the RR interval (SDNN), the root mean square of successive differences in RR intervals (RMSSD), the low frequency (LF) and high frequency (HF) in normalized and absolute units. The sample was split into two groups (low RR and high RR) to verify if this variable could differentiate between specific performance. For the SDNN, a significant and moderate correlation (r = 0.53) was found with the total number of throws and throws in the series A (r = 0.56) and B (r = 0.54) and for the RMSSD a correlation with throws during series B (r = 0.59) in the SJFT. However, the groups did not differ in performance and recovery. Therefore, HRV is related to intermittent judo performance; however, it cannot differentiate between judokas at different levels of performance.

Physicochemical characterization and antinociceptive and anti-inflammatory activities of atranorin (AT) extracted from Cladina kalbii Ahti in formalin- and capsaicin-induced orofacial pain and anti-inflammatory tests in rodents were studied. Physicochemical characterization showed that AT has the general formula C19H18O8. Male Swiss mice were pretreated with AT (100, 200, and 400 mg/kg, i.p.), morphine (3 mg/kg, i.p.), or vehicle (0.9% saline with two drops of 0.2% Tween 80) before formalin (20 μl, 2%) or capsaicin (20 μl, 2.5 μg) were injected into the right vibrissa. Our results showed that i.p. treatment with AT displayed marked inhibitory effects in different orofacial pain tests in mice. AT (400 mg/kg, i.p.) was effective in reducing the nociceptive face-rubbing behavioural response in both phases of the formalin test, which was also naloxone-sensitive. Additionally, AT produced a significant antinociceptive effect at all doses in the capsaicin test. Such results were unlikely to be provoked by motor abnormality, since AT-treated mice exhibited no performance alteration on the rota rod apparatus. AT exhibited significant anti-inflammatory activity in the acute model of inflammation (leukocyte migration to the peritoneal cavity), carrageenan- and arachidonic acid-induced hind paw edema in rats. Additionally, AT exhibited a dose-dependent antioxidant activity in vitro, as assessed by total radical-trapping antioxidant parameter and total antioxidant reactivity assays. All these findings suggest that AT might represent an important tool for the management of orofacial pain and/or inflammatory disorders