2-(Phenylcarbonothioylsulfanyl)acetic acid

The title compound, C(9)H(8)O(2)S(2), can be used as a chain transfer agent and may be used to control the behavior of polymerization reactions. O-H center dot center dot center dot O hydrogen bonds of moderate character link the molecules into dimers. In the crystal, the dimers are linked into sheets by C-H center dot center dot center dot O interactions, forming R(4)(2)(12) and R(2)(2)(8) edge-fused rings running parallel to [101]. There are no intermolecular interactions involving the S atoms.

2-[(2-Carboxyphenyl)disulfanyl]benzoic acid-4,4 '-bipyridyl N,N '-dioxide (1/2)

In the title 2:1 adduct, C(14)H(10)O(4)S(2)center dot 0.5C(10)H(8)N(2)O(2), which arose from an unexpected oxidation of a precursor, the dihedral angle between the aromatic rings in the disulfide is 82.51 (11)degrees. In the crystal, the molecules are linked by O-H center dot center dot center dot O, OH center dot center dot center dot N and C-H center dot center dot center dot O interactions, generating sheets.

3-Nitrobenzoic acid-3-methyl-4-nitropyridine 1-oxide (1/1)

The title adduct, C(7)H(5)NO(4)center dot C(6)H(6)N(2)O(3), forms part of an ongoing study of the design of non-centrosymmetric systems based on 3-methy-4-nitropyridine 1-oxide. The components of the adduct are linked by intermolecular O-H center dot center dot center dot O hydrogen bonds. The rings of the two components are nearly planar, with a dihedral angle of 11.9 (2)degrees between the planes. The supramolecular structure shows that molecules of the title complex are linked into sheets by a combination of strong O-H center dot center dot center dot O and weak C-H center dot center dot center dot O hydrogen bonds.

Ionic mobility of the solvated proton and acid-base titration in a four-compartment capillary electrophoresis system

Although H(+) and OH(-) are the most common ions in aqueous media, they are not usually observable in capillary electrophoresis (CE) experiments, because of the extensive use of buffer solutions as the background electrolyte. In the present work, we introduce CE equipment designed to allow the determination of such ions in a similar fashion as any other ion. Basically, it consists of a four-compartment piece of equipment for electrolysis-separated experiments (D. P. de Jesus et at, Anal. Chem., 2005, 77, 607). In such a system, the ends of the capillary are placed in two reservoirs, which are connected to two other reservoirs through electrolyte-filled tubes. The electrodes of the high-voltage power source are positioned in these reservoirs. Thus, the electrolysis products are kept away from the inputs of the capillary. The detection was provided by two capacitively coupled contactless conductivity detectors (CD), each one positioned about 11 cm from the end of the capillary. Two applications were demonstrated: titration-like procedures for nanolitre samples and mobility measurements. Strong and weak acids (pK(a) < 5), pure or mixtures, could be titrated. The analytical curve is linear from 50 mu M up to 10 mM of total dissociable hydrogen (r = 0.99899 for n =10) in 10-nL samples. By including D(2)O in the running electrolyte, we could demonstrate how to measure the mixed proton/deuteron mobility. When H(2)O/D(2)O (9 : 1 v/v) was used as the solvent, the mobility was 289.6 +/- 0.5 x 10(-5) cm(2) V(-1) s(-1). Due to the fast conversion of the species, this value is related to the overall behaviour of all isotopologues and isotopomers of the Zundel and Eigen structures, as well as the Stokesian mobility of proton and deuteron. The effect of neutral (o-phenanthroline) and negatively charged (chloroacetate) bases and aprotic solvent (DMSO) over the H(+) mobility was also demonstrated.

Intraspecific variability of dihydrochalcone, chromenes and benzoic acid derivatives in leaves of Piper aduncum L. (Piperaceae)

Chemical analysis carried out in leaves of 18 specimens of Piper aduncum L. (Piperaceae) occurring at Ripasa Reserve, Araraquara, SP, Brazil indicated two distinct populations when investigated over a period of 14 months (January 2000 to February 2001) and then submitted to cluster analysis. The two groups were characterized by accumulation of prenylated benzoic acids, chromenes and dihydrochalcone, respectively. A total of seven compounds were identified by HPLC analysis and compared with standards including two prenylated benzoic acid [aduncumene (1) and 3-(3'-7'-dimethyl-2'-6'-octadienyl)-4-methoxy-benzoic acid (5)], four chromenes [methyl 2,2-dimethyl-8-(3'-methyl-2'-butenyl)-2H-1-chromene-6-carboxylate (4), methyl 2,2-dimethyl-2H-1-chromene-6-carboxylate (2b), methyl 8-hydroxy-2,2-dimethyl-2H-1-chromene-6-carboxylate (3) and 2,2-dimethyl-2H-1-chromene-6-carboxylic acid (2a)] and one dihydrochalcone [2',6'-dihydroxy-4'-methoxy-dihydrochalcone (6)].

Redetermination of 3-methylbenzoic acid

The asymmetric unit of the title compound, C(8)H(8)O(2), contains two crystallographically independent molecules, which form dimers linked by O center dot center dot center dot H-O hydrogen bonds. The benzene rings in the dimers are inclined at a dihedral angle of 7.30 (8)degrees and both methyl groups display rotational disorder. This redetermination results in a crystal structure with significantly higher precision than the original determination [Ellas & Garcia-Blanco (1963). Acta Cryst. 16, 434], in which the authors reported only the unit-cell parameters and space group, without any detailed information on the atomic arrangement. In the crystal, dimers are connected by weak C-H center dot center dot center dot O interactions, forming R(2)(2)(10) and R(4)(4)(18) rings along [110] and an infinite zigzag chain of dimers along the [001] direction also occurs.

A flow-based procedure with solenoid micro-pumps for the spectrophotometric determination of uric acid in urine

The determination of uric acid in urine shows clinical importance, once it can be related to human organism dysfunctions, such as gout. An analytical procedure employing a multicommuted flow system was developed for the determination of uric acid in urine samples. Cu(II) ions are reduced by uric acid to Cu(I) that can be quantified by spectrophotometry in the presence of 2,2`-biquinoline 4,4`-dicarboxylic acid (BCA). The analytical response was linear between 10 and 100 mu mol L(-1) uric acid with a detection limit of 3.0 mu mol L(-1) (99.7% confidence level). Coefficient of variation of 1.2% and sampling rate of 150 determinations per hour were achieved. Per determination, 32 mu g of CuSO(4) and 200 mu g of BCA were consumed, generating 2.0 mL of waste. Recoveries from 91 to 112% were estimated and the results for 7 urine samples agreed with those obtained by the commercially available enzymatic kit for determination of uric acid. The procedure required 100-fold dilution of urine samples, minimizing sample consumption and interfering effects. In order to avoid the manual dilution step, on-line sample dilution was achieved by a simple system reconfiguration attaining a sampling rate of 95 h(-1). (C) 2009 Elsevier B.V. All rights reserved.

Determination of uranium in phosphoric acid using neutron activation analysis

Phosphoric acid is generally obtained from an aqueous process starting with the reaction between phosphate rock and sulphuric acid. Due to their chemical similarity, uranium is usually associated with phosphate rock which during chemical processing is partitioned to phosphoric acid. Uranium determination in this matrix is a very important task because of its ingestion it could lead to radiological impact on the population. Therefore, a procedure was developed using an initial precipitation with calcium hydroxide and evaporation, followed by instrumental neutron activation analysis (INAA). The procedure was applied to analyse fourteen uranium enriched phosphoric acid samples.

PRODUCTION OF (15)N-ENRICHED NITRIC ACID (H(15)NO(3))

Techniques that employ (15)N have proved to be an important tool in many areas of the agronomic and biomedical sciences. Nevertheless, their use is limited by methodological difficulties and by the price of compounds in the international market. Nitric compounds ((15)NO(3)(-)) have attracted the interest of researchers. However, these compounds are not currently produced in Brazil. Thus, in the present work H(15)NO(3) was obtained from the oxidation of anhydrous (15)NH(3). The method we used differs from the industrial process in that the absorption tower is replaced with a polytetrafluoroethylene-lined, stainless-steel hydration reactor. The process output was evaluated based on the following parameters: reaction temperature; ratio of reagents; pressure and flow of (15)NH(3(g)) through the catalyst (Pt/Rh). The results showed that, at the best conditions (500 degrees C; 50% excess O(2); 0.4 MPa; and 3.39 g. min(-1) of (15)NH(3)), a conversion percentage (N-(15)NH(3) to N-(15)NO(3)(-)) of 62.2%, an overall nitrogen balance (N-(15)NH(3) + N-(15)NO(3)(-)) of 86.8%, and purity higher than 99% could be obtained.

FATTY ACID COMPOSITION OF ACID, BIOLOGICAL AND ENZYMATIC FISH SILAGE

The use of the fish silage as an ingredient in feed for aquatic organisms is an alternative to solve sanitary and environmental problems caused by the lack of an adequate destination for the residues generated by the fishing industry. It would also lower the costs with feed, and consequently the fish production costs, since the expenses with the feed account for approximately 60% of the total cost. The objective of this study was to evaluate the fatty acid composition of the acid silage (AS), biological silage (BS) and enzymatic silage (ES) produced from discardings of the culture and from processing residues of the Nile tilapia (Oreochromis niloticus). The values found for lipids (dry matter basis) were: 12.45; 12.25 and 12.17 g 100 g(-1) for BS, AS, and ES, respectively. The fatty acids present in the lipid fraction of the silages are predominantly unsaturated. Oleic acid was present in larger amounts (30.49, 28.60 and 30.60 g 100 g(-1) of lipids for BS, AS and ES, respectively). Among saturated fatty acids, palmitic and stearic acids were present in larger amounts. Only traces of eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids were found. The silages produced from discardings of the culture and processing residues of the Nile tilapia are not a good source of EPA and DHA for fish feeds.

Effects of branched-chain amino acid (BCAA) supplementation on endurance exercise performance of pregnant rats

Aims. - The present study evaluated the effects of BCAA supplementation on exercise performance of pregnant rats. Methods. - In order to assess these effects, Wistar rats were divided into four groups: sedentary not-supplemented (SNS, n = 8); sedentary supplemented (SS, n = 8); trained not-supplemented (TNS, n = 8) and trained supplemented (TS, n = 8). All groups were submitted to the endurance test until exhaustion (ET) and post-effort lactate (PEL) determination before pregnancy (ET-B and PEL-B) and at the 19th day of pregnancy (ET-19 and PEL-19). Results. - The endurance training significantly increased the ET time to exhaustion (p<0.05). Regardless of BCAA supplementation, both endurance trained groups (TS and TNS) showed a longer time to exhaustion, assessed by ET, compared with the sedentary groups (SS and SNS) (p < 0.05). In the TNS, ET-19 time to exhaustion decreased when compared with the period before pregnancy. On the other hand, ET-19 time to exhaustion was not affected in the TS at the end of the pregnancy period. In addition, TS showed a marked PEL-19 reduction when compared with PEL-B. The data presented herein suggest that BCAA supplementation plays an ergogenic role in the maintenance of exercise performance during pregnancy in rats. (C) 2008 Elsevier Masson SAS. All rights reserved.

Severe Lactic Acidosis Treated With Prolonged Hemodiafiltration in a Disseminated Histoplasmosis

Infections with Histoplasma are rarely seen in immunocompromized patients. We report the case of a renal transplant recipient who presented with disseminated histoplasmosis 3.5 years after transplant He presented severe lactic acidosis (LA), sepsis complicated by circulatory failure, renal failure, and liver dysfunction. We describe the successful use of continuous venovenous hemodiafiltration (CVVHDF) with regional citrate anticoagulation, treatment that stabilized our patient until infectious focus was identified and treated. The lactate was decreasing, concomitant with hemodynamic improvement, with reduction and suspension of the norepinephrine. The serum lactate level normalized 52 hours after CVVHDF initiated (from 28.9 to 2.2 mmol/L). Continuous renal replacement therapy was safely applied and can be recommended as an efficient method on adjuvant treatment of hyperlactatemia. ASAIO Journal 2009; 55:123-125.

Psychosocial perspectives of the partners of breast cancer patients treated with a mastectomy

The family members of cancer patients play a central role as caregivers. This study reports on the perspectives of men whose wives underwent a mastectomy because of breast cancer. This qualitative research used a narrative analysis method, and 17 men were interviewed. Five main themes emerged from the analysis of the narratives: initial reactions to the diagnosis, involvement in caregiving, support received, influence of breast cancer on the couples` relationships, and evaluation of care provided by the institution. The findings indicated the existence of substantive evidence that the spouses attended to and followed the recommendations of healthcare providers on ways to care for their wives, including their emotional demands and care needs. In this sense, the healthcare professionals should interact with a. patient`s primary caregiver, take the family dynamics and the caregiver`s personal characteristics into account, and systematically consider and include the needs of the patients` caregivers in the entire healthcare process.

Effect of Oxalate Desensitizer on the Durability of Resin-Bonded Interfaces

Potassium oxalate desensitizers were previously shown to effectively reduce the immediate permeability of resin-bonded dentin. The current study evaluated whether the effect of the combined application of oxalate with etch-and-rinse adhesives interferes with the durability of resin-dentin bonds when using etch-and-rinse adhesives. The bond strength of resin-bonded dentin specimens composed of two-step or three-step etch-and-rinse adhesives (Single Bond, One-Step and Scotchbond Multi-Purpose, respectively) was tested immediately (24 hours) and after 12 months of water storage. The adhesives were used either according to the manufacturers` instructions (control groups) or after treating acid-etched dentin with a potassium oxalate gel (BisBlock, BISCO, Inc). The treatment of dentin with potassium oxalate was shown to negatively affect the baseline bond strength of resin-bonded dentin specimens, regardless of the adhesive used (p<0.05). After storage, the bond strength of the resin-bonded interfaces was significantly reduced for all the tested groups (p<0.001). Nevertheless, the rate of decreasing bond strength was significantly lower for oxalate-treated specimens than for the controls (p<0.05).

Radicicol improves regeneration of skeletal muscle previously damaged by crotoxin in mice

This work investigates the influence of heat shock proteins (HSPs) on necrosis and subsequent skeletal muscle regeneration induced by crotoxin (CTX), the major component of Crotalus durissus terrificus venom. Mice were treated with radicicol, a HSP inductor, followed by an intramuscular injection of CTX into the gastrocnemius muscle. Treated groups were sacrificed 1, 10 and 21 days after CTX injection. Muscle histological sections were stained with toluidine blue and assayed for acid phosphatase or immunostained with either neuronal cell adhesion molecule (NCAM) or neonatal myosin heavy chain (MHCn). Muscle samples were also submitted to Western blotting analysis. The results show that CTX alone and CTX combined with radicicol induced a similar degree of myofiber necrosis. CTX-injured muscles treated with radicicol had increased cross-sectional areas at 10 and 21 days post-lesion compared with untreated CTX-injured muscles. Additionally, radicicol significantly increased the number of NCAM-positive satellite cells in the gastrocnemius at one day post-CTX injury. CTX-injured Muscles treated with radicicol contained more MHCn-positive regenerating myofibers compared with untreated CTX-injured muscles. These results suggest that HSPs contribute to the regeneration of myofibers damaged by CTX. Additionally, further studies should investigate the potential therapeutic effects of radicicol in skeletal muscles affected by Crotalus venom. (C) 2008 Elsevier Ltd. All rights reserved.