Investigating the binding heterogeneity of trace metal cations with SiO2 nanoparticles using full wave analysis of stripping chronopotentiometry at scanned deposition potential

Silica oxides nano- and microparticles, as well as silica-based materials, are very abundant in nature and industrial processes. Trace metal cation binding with these bulk materials is generally not considered significant in speciation studies in environmental systems. Nonetheless, this might change for nanoparticulate systems as observed in a previous study of Pb(II) with a very small SiO2 particle (7.5 nm diameter). Besides, metal binding by those nanoparticles is surprisingly characterized by a heterogeneity that increases with the decrease of metal-to-particle ratio. Therefore, it is interesting to extend this study to investigate different trace metals and the influence of the nanoparticle size on the cation binding heterogeneity. Consequently, the Cd(II), Pb(II), and Zn(II) binding by two different sized SiO2 nanoparticles (Ludox LS30 and TM40) in aqueous dispersion was studied for a range of pH and ionic strength conditions, using the combination of the electroanalytical techniques Scanned Stripping ChronoPotentiometry and Absence of Gradients and Nernstian Equilibrium Stripping. The coupling of these techniques provides the free metal concentration in the bulk (AGNES) and information of the free and complex concentration at the electrode surface for each Stripping Chronopotentiometry at Scanned deposition Potential (SSCP). A recent mathematical treatment allows the reconstruction of a portion of the metal to ligand binding isotherm with the included heterogeneity information using the full SSCP wave analysis. In this work, we observed that the Zn(II) binding is homogeneous, Cd(II) is slightly heterogeneous, and Pb(II) is moderately heterogeneous, whereas the results obtained with the 7.5 nm diameter nanoparticle are slightly more heterogeneous than those obtained with the one of 17 nm. These findings suggest that the Zn(II) binding is electrostatic in nature, and for both Cd(II) and Pb(II), there should be a significant chemical binding contribution.FCT-ANR/AAG-MAA/0065/2012info:eu-repo/semantics/publishedVersio

Potencial estabilizante de éster de sacarose em suco de graviola (Annona muricata, L.)

Esteres de sacarose são compostos com propriedades tensoativas (biosurfactantes), isto é, capazes de reduzir a tensão superficial e promover a emulsificação de líquidos imiscíveis. Como todas as emulsões, o suco de graviola não é fisicamente estável e é propenso a uma separação de fases. O objetivo do presente trabalho foi avaliar a aplicação do éster de sacarose na estabilização de emulsões de suco de graviola. O éster de sacarose foi adicionado às amostras de suco de graviola nas proporções de 1:10, 1:50 e 1:100 (éster de sacarose:suco de graviola) e caracterizado de acordo com a tensão superficial, índice de emulsificação, potencial zeta e análise microscópica. A análise microscópica apresentou maior aglomerado de glóbulos na amostra B (1:10, éster de sacarose:suco de graviola, p/v). Os resultados das demais análises indicaram que a amostra C (1:50, éster de sacarose:suco de graviola, p/v) apresentou a melhor estabilidade, com uma tensão superficial de 35 N/m e um índice de emulsificação de 50.4 % durante 24 horas de experimento

Effects of Early Changes in Organ Dysfunctions on the Outcomes of Critically Ill Patients in Need of Renal Replacement Therapy

INTRODUCTION: Acute kidney injury usually develops in critically ill patients in the context of multiple organ dysfunctions. OBJECTIVE: To evaluate the effect of changes in associated organ dysfunctions over the first three days of renal replacement therapy on the outcomes of patients with acute kidney injury. METHODS: Over a 19-month period, we evaluated 260 patients admitted to the intensive care units of three tertiary-care hospitals who required renal replacement therapy for > 48 h. Organ dysfunctions were evaluated by SOFA score (excluding renal points) on the first (D1) and third (D3) days of renal replacement therapy. Absolute (A-SOFA) and relative (D-SOFA) changes in SOFA scores were also calculated. RESULTS: Hospital mortality rate was 75%. Organ dysfunctions worsened (A-SOFA>0) in 53%, remained unchanged (A-SOFA=0) in 17% and improved (A-SOFA<0) in 30% of patients; and mortality was lower in the last group (80% vs. 84% vs. 61%, p=0.003). SOFA on D1 (p<0.001), SOFA on D3 (p<0.001), A-SOFA (p=0.019) and D-SOFA (p=0.016) were higher in non-survivors. However, neither A-SOFA nor D-SOFA discriminated survivors from non-survivors on an individual basis. Adjusting for other covariates (including SOFA on D1), A-SOFA and D-SOFA were associated with increased mortality, and patients in whom SOFA scores worsened or remained unchanged had poorer outcomes. CONCLUSIONS: In addition to baseline values, early changes in SOFA score after the start of renal replacement therapy were associated with hospital mortality. However, no prognostic score should be used as the only parameter to predict individual outcomes

Cell block sensitivity for immunohistochemical detection of cytokeratin 5, oestrogen and progesterone receptors in canine primary mammary carcinoma

Mammary carcinomas are relatively common ailments among female canines aged around 10 years old, presentingan important morbidity with an average survival of five years. The cytoinclusion technique is frequently employed in human medicine as the investigative method of choice as it quickly provides resources for the determination of the correct therapeutic response, however, the effectiveness of the technique in canines remains understudied in veterinary medicine. This study aims at evaluating the degree of correlation with immunohistochemical marking for cytokeratin 5 (CK5), oestrogen and progesterone receptors (ER and PR) between the cytoinclusion and the histopathology technique in mammary carcinomas. Twenty-five samples of mammary carcinoma, both for the cytoinclusion and histopathological techniques were submitted for histological processing; microscope slides were created for hematoxylin-eosin (HE) staining and the immunohistochemical technique (IHC) was assessed for the ER, PR and CK5 receptors. Through the HE staining, we reached a concordance rate of 100% between the cytoinclusion and the histopathological analysis in the diagnosis of carcinomas. The immunohistochemical assay presented sensitivity of 85.71%, 95.45% and 100% and Cohen’s kappa of 0.78, 0.84 and 0.95 for ER, PR and CK5, respectively, as well as 100% specificity and P&lt;0.01 for all three markers. Therefore, cytoinclusion represents an accessible, fast and low-cost method, offering high sensitivity for the cytomorphological and immunohistochemical diagnosis of mammary carcinoma in female canines

Producing magnetic nanocomposites from paper sludge for the adsorptive removal of pharmaceuticals from water: a fractional factorial design

In view of a simple after-use separation, the potentiality of producing magnetic activated carbon (MAC) by intercalation of ferromagnetic metal oxide nanoparticles in the framework of a powder activated carbon (PAC) produced from primary paper sludge was explored in this work. The synthesis conditions to produce cost effective and efficient MACs for the adsorptive removal of pharmaceuticals (amoxicillin, carbamazepine, and diclofenac) from aqueous media were evaluated. For this purpose, a fractional factorial design (FFD) was applied to assess the effect of the most significant variables (Fe3+ to Fe2+ salts ratio, PAC to iron salts ratio, temperature, and pH), on the following responses concerning the resulting MACs: Specific surface area (SBET), saturation magnetization (Ms), and adsorption percentage of amoxicillin, carbamazepine, and diclofenac. The statistical analysis revealed that the PAC to iron salts mass ratio was the main factor affecting the considered responses. A quadratic linear regression model A = f(SBET, Ms) was adjusted to the FFD data, allowing to differentiate four of the eighteen MACs produced. These MACs were distinguished by being easily recovered from aqueous phase using a permanent magnet (Ms of 22-27 emu g-1), and their high SBET (741-795 m2 g-1) were responsible for individual adsorption percentages ranging between 61% and 84% using small MAC doses (35 mg L-1).publishe

Cladosporium tenuissimum URM 7803: a promising new β-galactosidase producer

The Cladosporium genus, defined by Link in 1816, is one of the largest and most heterogeneous Hyphomycetes genus. It comprises more than 189 species still rarely explored biotechnologically. One of the most studied microbial enzymes, -galactosidase is a glycoside hydrolase enzyme that catalyzes the hydrolysis of -galactosides into monosaccharides through the breaking of a glycosidic bond. Recently, new studies comprising new microbial sources of -galactosidase, presenting biotechnologically interesting characteristics, have been encouraged. In this context, the present study evaluated the production of -galactosidase by a new isolate of Cladosporium tenuissimum. A C. tenuissimum inoculum was prepared adding 107 spore/mL in sterile saline solution 0.85% (w/v) NaCl containing 0.01% (w/v) Tween 80 and added to fermentation medium for enzyme production. The fermentation medium, composed of (% w/v): lactose (2), peptone (0.4), yeast extract (0.4) and salts (KH2PO4 (0.2), Na2HPO4.12H2O (0.8) and MgSO4.7H2O (0.025), pH 6.5, was maintained at 28° C and 180 rpm for 13 days. One sample (50 mL erlenmeyer) was removed every 24 hours and -galactosidase activity was evaluated using ONPG (ortho-Nitrophenyl--galactoside) method. The results showed maximum -galactosidase production by C. tenuissimum URM 7803 on thirteenth day, displayed enzymatic activity of 462.13 U/mL. The C. tenuissimum URM 7803 isolate proved to be a powerful new -galactosidase producer with potential application for food processing.info:eu-repo/semantics/publishedVersio

Synthesis, characterization, antibacterial and antitumoral activities of mononuclear zinc complexes containing tridentate amine based ligands with N3 or N2O donor groups

The synthesis and characterization of the four zinc(II) complexes [Zn(HL1)Cl-2] (1), [Zn(H2L2)Cl-2](2), [Zn(H2L3)Cl-2] (3) and[Zn(H2L4)Cl-2] (4), where HL1 = (bis-2-pyridylmethyl)amine, H2L2 = (2-hydroxybenzyl- 2-pyridylmethyl) amine, H2L3 = N-2[(pyridine-2-ylmethyl)amino)ethanol, H2L4 = 1-[(pyridine-2-ylmethyl)- amino]-propan-2-ol are reported; (3) and (4) are new while (2) was reported previously but its structure had not been determined. The complexes were characterized by elemental analysis, IR, UV-Vis and NMR spectroscopic, electrospray ionization mass spectrometry (ESI(+)-MS) and tandem mass spectrometry ESI(+)-MS/MS). X-ray diffraction studies were performed for complexes (1)-(3) revealing the presence of mononuclear structures in the solid state. The X-ray analyses of (1) and (3) demonstrate that HL1 and HL2 act as tridentate ligands, while the ligand H2L2 in (2) is bidentate. The cytotoxic properties of the ligands and of all the complexes were examined using human leukemia THP-1, U937 and Molt-4 cells. Complex (4) exhibited the highest cytotoxicity in this series with an IC50 value of 75 +/- 1 mu mol L (1) against U937 cells. Transmission electron microscopy (TEM) reveals ultrastructural changes typical of apoptotic cells. The induction of apoptosis was confirmed by the annexin V assay. The antimicrobial activity of complexes (1)-(4) was also investigated in vitro against four Gram-positive bacteria (ATCC10832, ATCC25923, COL) and the clinical Staphylococcus aureus isolate LSA88 (SEC/SEF/ TSST-1+). Complex (2) showed the most potent inhibitory activity, reaching almost 100% of inhibition against all strains tested. Morphological investigations using TEM indicate that the antibacterial activity of complex (2) may be associated with the inhibition of cell wall and therefore cell division. (C) 2014 Elsevier B. V. All rights reserved