Functional correlation between cerebellum and basal ganglia: A parkinsonism model.

INTRODUCTION: The cerebellar response has been studied for years with different models of alteration of other brain structures to understand its complex functioning and its relationship with the rest of the body. Studies in patients with Parkinson's disease (PD) showed that the cerebellar function is modified by deficit of the basal ganglia; which supports the hypothesis that both structures are related anatomically and functionally. METHODS: In our study, the ventrolateral striatum (VLS) of the basal ganglia was altered by an electrolytic lesion, in order to produce a similar jaw frequency of jaw tremor movements presented in parkinsonism, thereafter we analyzed the effect of the lesion on the expression of multiunit activity (MUA) of the cerebellum. RESULTS: We found cerebellar activation during mandibular movements and increment during oral jaw tremor movements. In addition, the amplitude of baseline MUA registered in animals with alteration of the VLS decreased with respect to the intact group. CONCLUSIONS: Accordingly, we conclude that cerebellar changes in MUA may be due to a decrease in the cerebellar inflectional or as a possible compensatory function between cerebellum and basal ganglia.

Photocatalytic degradation of acid yellow 36 with calcined titania-hydroxyapatite-cuo xerogels.

Advanced oxidation processes (AOP), using semiconductor (SC) and hydroxyapatite (HA) composites, are promising due to the synergy of photocatalytic and adsorption properties. Still, dye removal efficiency of composites based on HA-SC remains low, because most of the research reported consider single SC materials. In this work, nanocrystalline xerogels of titanium oxide (TiO2) with copper oxide (CuO) and HA were synthesized by the sol-gel process. HA was obtained by the precipitation method without heat treatment and calcined in the range of 200-1000 °C. TiO2 and copper precursors were added to a sol containing HA in a 12:1 mol ratio, obtaining HA-TiO2 and HA-CuO-TiO2 nanomaterials. The xerogels were characterized by X-ray diffraction, scanning electron microscopy, emission field scanning electron microscopy and photoresponse. Their performance in the photocatalytic discoloration of an aqueous solution acid yellow dye 36 (AY36) was evaluated, using visible and UV light. The best discoloration was achieved with HA-CuO-TiO2 xerogels with HA calcined at 600 °C, showing a degradation kinetic constant of 0.24 min-1. In contrast, HA-TiO2 materials showed little or no photocatalytic activity, but strong dye adsorption/desorption. The thermal treatment of HA determines the filament-like morphology and degree of compaction of the nanomaterials, which are relevant in the crystallite size and sensitization of the SC matrix. Further studies must address the surface chemistry and rectifying properties of the best SC composite to have a more complete understanding of the mechanisms involved.

Apropiación de los elementos de innovación social en organizaciones comunitarias agropecuarias del departamento de Boyacá, Colombia / Appropriation of the elements of social innovation in community agricultural organizations of the department of Boyaca, Colombia

RESUMEN Con el objetivo de establecer criterios mínimos relativos a la innovación social en organizaciones comunitarias agropecuarias, se hizo uso de herramientas propias de la investigación cualitativa que incluyeron búsquedas especializadas y uso de programas para análisis de datos bibliográficos (por ejemplo VOSviewer™) para determinar los elementos relativos a la gestión, gobernanza, capacidades, modelo de negocio sostenibilidad para ocho (8) organizaciones comunitarias de productores agropecuarios de la provincia del Sugamuxi, en el departamento de Boyacá, Colombia. Se pudo establecer que algunas organizaciones de productores agropecuarios que ejercen actividades en el departamento de Boyacá no están apropiando de forma integral los elementos de innovación social (en niveles operativos y gerenciales) y, consecuentemente, existe toda una ruta de mejoramiento por desarrollar con estas para optimizar los índices de eficiencia organizacional; además, se evidencia la complejidad de la temática, dado que la sostenibilidad de las innovaciones sociales dependerá en gran medida de la gestión de las organizaciones, donde se establezcan agendas institucionales compartidas contextualizadas y ajustadas a los territorios. Es necesario optimizar los canales de participación de manera mancomunada entre el Estado, las organizaciones y los mismos productores para poder dinamizar procesos, metas y alcances reales de la innovación social a la luz de los acelerados cambios a los que se enfrenta el productor agropecuario agremiado en Colombia, relativos estos a la dinámica del mercado, el acceso a recursos y otros.

ABSTRACT In order to establish minimum criteria related to social innovation in agricultural community organizations, qualitative research tools were used, including specialized searches and the use of programs for the analysis of bibliographic data (for example VOSviewer™), with the purpose of defining the elements related to management, governance, capacities, business model and sustainability for eight (8) community organizations of agricultural producers in the province of Sugamuxi, in the department of Boyacá, Colombia. It was possible to establish that some organizations of agricultural producers that carry out activities in the department of Boyacá are not integrally appropriating the elements of social innovation (at operational and managerial levels) and, consequently, there is a whole route of improvement to be developed with them to optimize the organizational efficiency indexes; in addition, the complexity of the subject is evident, given that the sustainability of social innovations will depend largely on the management of the organizations, where shared institutional agendas contextualized and adjusted to the territories are established. It is necessary to optimize the channels of participation in a joint manner between the State, the organizations, and the producers themselves to be able to dynamize processes, goals and the real scope of social innovation in light of the accelerated changes faced by the agribusiness producer in Colombia, related to market dynamics, access to resources and others.

Impact of Cadmium Mediated by Tobacco Use in Musculoskeletal Diseases.

Tobacco use has a negative impact on health due to its relationship with the development of high-mortality diseases, such as pulmonary cancer. However, the effect of cadmium (Cd), present in tobacco smoke, on the development of joint diseases has been scarcely studied. The objective of this review is to discuss the evidence regarding the mechanisms by which Cd exposure, through tobacco smoke, may lead to the development of osteoarthritis (OA), osteoporosis (OP), and rheumatoid arthritis (RA). There's evidence suggesting a string association between moderate to severe OA development and tobacco use, and that a higher blood concentration of Cd can trigger oxidative stress (OS) and inflammation, favoring cartilage loss. At the bone level, the Cd that is inhaled through tobacco smoke affects bone mineral density, resulting in OP mediated by a decrease in the antioxidant enzymes, which favors the bone resorption process. In RA, tobacco use promotes the citrullination process through Cd exposure and increases OS and inflammation. Understanding how tobacco use can increase the damage at the articular level mediated by a toxic metal, i.e., Cd, is important. Finally, we propose prevention, control, and treatment strategies for frequently disabling diseases, such as OA, OP, and RA to reduce its prevalence in the population.

Abdominal compartment syndrome: Current concepts and management. / Síndrome compartimental abdominal: conceptos actuales y manejo.

Abdominal compartment syndrome occurs when 2 or more anatomic compartments have a sustained intra-abdominal pressure >20mmHg, associated with organ failure. Incidence is 2% and prevalence varies from 0% to 36.4%. A literature search was conducted utilizing different databases. Articles published from 1970 to 2018 were included, in English or Spanish, to provide the concepts, classifications, and comprehensive management in the approach to abdominal compartment syndrome, for its treatment and the prevention of severe complications associated with the entity. Intravesical pressure measurement is the standard diagnostic method. Treatment is based on evacuation of the intraluminal content, identification and treatment of intra-abdominal lesions, improvement of abdominal wall compliance, and optimum administration of fluids and tissue perfusion. Laparotomy is generally followed by temporary abdominal wall closure 5 to 7 days after surgery. Reconstruction is performed 6 to 12 months after the last operation. Abdominal compartment syndrome should be diagnosed and operated on before organic damage from the illness occurs. Kidney injury can frequently progress and is a parameter for considering abdominal decompression. Having a biomarker for early damage would be ideal. Surgical treatment is successful in the majority of cases. A multidisciplinary focus is necessary for the intensive care and reconstructive needs of the patient. Thus, efforts must be made to define and implement strategies for patient quality of life optimization.

Toxicity of cadmium in musculoskeletal diseases.

Epidemiological studies have reported that exposure to toxic metals like cadmium (Cd) may promote the development of musculoskeletal diseases, such as osteoporosis, rheumatoid arthritis (RA), and osteoarthritis (OA), among others. The objective of this review is to summarize the molecular mechanisms of inflammation and oxidative stress activated by Cd at the bone level, particularly in osteoporosis, RA, and OA. Cadmium can increase bone resorption, affect the activity of osteoclasts and calcium (Ca) absorption, and impair kidney function, which favors the development of osteoporosis. In the case of RA, Cd interferes with the activity of antioxidant proteins, like superoxide dismutase (SOD) and catalase (CAT). It also promotes an inflammatory state, inducing the process of citrullination, which affects the proteins of immune response. On the other hand, accumulation of Cd in the tissues and blood of smokers has been related to the development of some musculoskeletal diseases. Therefore, knowing the negative impact of Cd toxicity at the articular level can help understand the damage mechanisms it produces, leading to the development of such diseases.

Heavy Metal Content in Chilean Fish Related to Habitat Use, Tissue Type and River of Origin.

In this study, we analyze the concentration of ten metals in two freshwater fish-the benthic catfish Trichomycterus areolatus and the limnetic silverside Basilichthys microlepidotus-in order to detect possible accumulation differences related to fish habitat (benthic or pelagic), tissue type (gill, liver and muscle), and the river of origin (four different rivers) in central Chile. The MANOVA performed with all variables and metals, revealed independent effects of fish, tissue and river. In the case of the fish factor, Cu, Cr, Mo and Zn showed statistically higher concentrations in catfish compared with silverside for all tissues and in all rivers (p < 0.05). In the case of the tissue factor, Al, Cr, Fe and Mn had statistically higher concentrations in liver and gills than in muscle (p < 0.05). For the river effect, the analysis showed higher concentrations of Cr, Mn and Pb in the Cogoti river and the lower concentrations in the Recoleta river. These results suggest that not all metals have the same pattern of accumulation; however, some metals tend to accumulate more in readily catfish, probably due to their benthic habit, and in liver and gill tissue, probably as a result of accumulation from food sources and respiration.

Olfactory conditioned same-sex partner preference in female rats: Role of ovarian hormones.

The dopamine D2-type receptor agonist quinpirole (QNP) facilitates the development of conditioned same-sex partner preference in males during cohabitation, but not in ovariectomized (OVX) females, primed with estradiol benzoate (EB) and progesterone (P). Herein we tested the effects of QNP on OVX, EB-only primed females. Females received a systemic injection (every four days) of either saline (Saline-conditioned) or QNP (QNP-conditioned) and then cohabited for 24h with lemon-scented stimulus females (CS+), during three trials. In test 1 (female-female) preference was QNP-free, and females chose between the CS+ female and a novel female. In test 2 (male-female) they chose between the CS+ female and a sexually experienced male. In test 1 Saline-conditioned females displayed more hops & darts towards the novel female, but QNP-conditioned females displayed more sexual solicitations towards the CS+ female. In test 2 Saline-conditioned females displayed a clear preference for the male, whereas QNP-conditioned females displayed what we considered a bisexual preference. We discuss the effect of dopamine and ovarian hormones on the development of olfactory conditioned same-sex preference in females.

Draft Genome Sequence of Enterococcus casseliflavus PAVET15 Obtained from the Oviduct Infection of the Cattle Tick (Rhipicephalus microplus) in Jiutepec, Morelos, Mexico.

Enterococcus spp. are Gram-positive lactic acid-producing bacteria found in the intestinal tracts of animals, like mammals, birds, and arthropods. Enterococcus spp. may cause oportunistic infections in vertebrate and invertebrate hosts. We report here the draft genome sequence of Enterococcus casseliflavus PAVET15 containing 3,722,480 bp, with 80 contigs, an N50 of 179,476 bp, and 41.93% G+C content.

Genomewide association analysis of growth traits in Charolais beef cattle.

The objective of this study was to perform a genomewide association study (GWAS) for growth traits in Charolais beef cattle and to identify SNP markers and genes associated with these traits. Our study included 855 animals genotyped using 76,883 SNP from the GeneSeek Genomic Profiler Bovine HD panel. The examined phenotypic data included birth, weaning, and yearling weights as well as pre- and postweaning ADG. After quality control, 68,337 SNP and 823 animals were retained in the analysis. The association analysis was performed using the principal components method via the egscore function of the GenABEL version 1.8-0 package in the R environment. Eighteen SNP located in 13 BTA were associated with growth traits ( < 5 × 10). The most important genes in these genomic regions were (), (), (), (), and ( [angiotensinase C]), due to their relationships with perinatal and postnatal survival, bone growth, cell adhesion, regulation of adipogenesis, and appetite. In conclusion, this study is the first to describe a GWAS conducted in beef cattle in Mexico and represents a basis for further and future research. This study detected new QTL associated with growth traits and identified 5 positional and functional candidate genes that are potentially involved in variations of the analyzed traits. Future analyses of these regions could help to identify useful markers for marker-assisted selection and will contribute to the knowledge of the genetic basis of growth in cattle and be a foundation for genomic predictions in Mexican Charolais cattle.

First Report of Rust Caused by Puccinia psidii on Eucalyptus dunnii in Uruguay.

Eucalypt rust caused by Puccinia psidii Winter represents a major disease affecting eucalypt production in South America, and is threatening myrtaceous hosts worldwide. In Uruguay, it was first detected infecting Eucalyptus globulus in 2001 (4) and later on E. grandis, Myrrhinium atropurpureum, and Myrcianthes pungens, two myrtaceae hosts native to Uruguay (3). Over the summer 2013, bright orange-yellowish pustules were detected on stock plants of E. dunnii in a nursery located in western Uruguay, province of Paysandú. A severe and explosive epidemic was readily observed. Affected leaves were taken to the laboratory and examined under the microscope. Uredinia and urediniospores were similar with those described previously in Uruguay on other hosts (3,4). Uredioniospores were 18 to 25 × 15 to 21 µm, yellow, unicellular, spherical to elliptical, base truncate, finely and uniformly echinulate with spines up to 1 µm long, with an evident bald patch without spines. To confirm identity of this fungus, genomic DNA was extracted from single-pustule urediniospores, and ITS region was amplified using primers PR1 and PR2 (1) with PCR conditions previously described (3). Forward and reverse sequences from three single pustules were obtained, assembled, and compared with those available in GenBank using BLAST searches. Obtained sequences showed to be identical to those analyzed by Pérez et al. (2011) collected from E. grandis and E. globulus, with no variation found in the analyzed region. A 100% identity was found with isolates UY1374 and UY1375 obtained from E. globulus, and with isolate UY1731 obtained from E. grandis (FJ710805, FJ710806, and FJ710807, respectively). Sequences were deposited in GenBank with accession numbers KM083129, KM083130, and KM083131. Even though this pathogen is known to occur in a wide variety of myrtaceous species, to our knowledge, this is the first natural infection record of P. psidii on E. dunnii in Uruguay and worldwide. This report confirms previous studies that indicated the susceptibility of E. dunnii when inoculated under controlled conditions (2,5). E. dunnii is being widely planted in Uruguay, eastern Argentina, and southern Brazil, with increasing significance to the pulp industry. Although the consequences of this finding have yet to be realized, scouting plantations is essential to estimate the real impact of this pathogen on this tree species. Our study contributes to expand the host range known for this globally important pathogen. References: (1) S. R. H. Langrell et al. Plant Pathol. 57:687, 2008. (2) L. Morin et al. PLoS ONE 7:e35434, 2012. (3) C. A. Pérez et al. Mycol. Progress 10:273, 2011. (4) N. Telechea et al. Plant Pathol. 52:427, 2003. (5) E. A. V. Zauza et al. Australas. Plant Pathol. 39:406, 2010.

Species of Mycosphaerellaceae and Teratosphaeriaceae on native Myrtaceae in Uruguay: evidence of fungal host jumps.

Mycosphaerella species are well-known causal agents of leaf diseases on many economically and ecologically important plant species. In Uruguay, a relatively large number of Mycosphaerellaceae and Teratosphaeriaceae are found on Eucalyptus, but nothing is known of these fungi on native Myrtaceae. The aim of this study was to identify Mycosphaerellaceae and Teratosphaeriaceae species associated with leaf diseases on native Myrtaceae in Uruguay and to consider whether host jumps by the pathogen from introduced Eucalyptus to native Myrtaceae have occurred. Several native forests throughout the country were surveyed with special attention given to those located close to Eucalyptus plantations. Five species belonging to the Mycosphaerellaceae and Teratosphaeriaceae clades were found on native Myrtaceous trees and three of these had previously been reported on Eucalyptus in Uruguay. Those occurring both on Eucalyptus and native Myrtaceae included Pallidocercospora heimii, Pseudocercospora norchiensis, and Teratosphaeria aurantia. In addition, Mycosphaerella yunnanensis, a species known to occur on Eucalyptus but not previously recorded in Uruguay, was found on leaves of two native Myrtaceous hosts. Because most of these species occur on Eucalyptus in countries other than Uruguay, it appears that they were introduced in this country and have adapted to be able to infect native Myrtaceae. These apparent host jumps have the potential to result in serious disease problems and they should be carefully monitored.

[Comparison of glycemic control in diabetic patients with and without metabolic syndrome]. / Comparación del control glucémico en pacientes diabéticos con y sin síndrome metabólico.

OBJECTIVE: To compare the glycemic level patients with type 2 diabetes (T2DM) with and without Metabolic syndrome (MS). METHODOLOGY: cross sectional study. Included patients randomly DM2 corroborated in your clinical record. The SM was identified in patients with at least 3 of 5 criteria of ATP III (Adult Treatment Panel III). A questionnaire was structured. Hemoglobin was determined (HbA1c), HDL-cholesterol, triglycerides, hypertension (HBP), body mass index (BMI), waist circumference (WC) and hip (NCC). RESULTS: 283 patients were included. Mean age was 59.8 ± 10.6. The predominant sex was female (73.6%). SM Criteria were : low HDL: 62.9%; hypertriglyceridemia: 56.3%; obesity abdominal (OA) 90.1%, hypertension (HBP): 62.5%. The prevalence of MS was 86.6% (95% CI 83% to 89%). There was significant difference in mean HbA1c level in patients with and without MS, HAS, OR, and low HDL. In contrast, subjects with hypertriglyceridemia had an HbA1c level significantly higher than those without hypertriglyceridemia (8.9% 2.3 vs 8.5% 2.1, respectively, P = 0.01). HbA1c is positively correlated with triglycerides (r = 0.24, p = 0.001), and negatively with weight (r = -0.19, p = 0.001), BMI (r = -0172, p = 0.004), CCI (r = -0.12, P = 0.004) and CCA (r = -0.14, p = 0.02). In adjusted multivariate analysis, only the duration of diabetes was associated with glycemic level (OR = 1.014, 95% in 1.010 to 1.016). CONCLUSIONS: We not found differences significant glycemic level in patients with and without MS.

Objetivo: Comparar el nivel glucémico en pacientes con diabetes tipo 2 (DM2) con y sin síndrome metabólico (SM). Metodología: Estudio transversal analítico. Se incluyeron aleatoriamente pacientes con DM2 corroborado en su expediente clínico. El SM se identificó en pacientes con al menos 3 de 5 criterios del ATP III (AdultTreatment Panel III). Se aplicó un cuestionario estructurado. Se determinó hemoglobina glucosilada (HbA1c), colesterol-HDL, triglicéridos, hipertensión arterial sistémica (HAS), índice de masa corporal (IMC), circunferencia de cintura (CCi) y cadera (CCa). Plan de análisis: prevalencia, prueba t de Student, correlación de Pearson y regresión logística. Resultados: Se incluyeron 283 pacientes. Edad promedio: 59.8±10.6 años. Predominó el sexo femenino (73.6%)Criterios cubiertos para SM: hipocolesterolemia-HDL: 62.9%; hipertrigliceridemia: 56.3%; obesidad abdominal (OA) 90.1%; hipertensión arterial sistémica (HAS): 62.5%. La prevalencia de SM fue 86.6% (IC95% 83% a 89%). No hubo diferencia significativa en el promedio de HbA1c en pacientes con y sin SM, HAS, OA, e hipocolesterolemia-HDL. En cambio, sujetos con hipertrigliceridemia tuvieron un promedio significativamente mayor de HbA1c que aquellos sin hipertrigliceridemia (8.9±2.3 vs 8.5±2.1, respectivamente; p=0.01). HbA1c correlacionó positivamente con trigliceridemia (r=0.24, p=0.001), y negativamente con el peso (r= -0.19, p=0.001), IMC (r= -0.172, p=0.004), CCi (r= -0.12, p=0.004) y CCa (r=-0.14, p=0.02). En el análisis multivariado ajustado, solamente la duración de la diabetes se asoció con el nivel glucémico (OR= 1.014, IC95% 1.010 a 1.016). Conclusiones: No encontramos diferencias significativas en el nivel glucémico en pacientes con y sin SM.

Comparación del control glucémico en pacientes diabéticos con y sin síndrome metabólico. / [Comparison of glycemic control in diabetic patients with and without metabolic syndrome].

OBJECTIVE: To compare the glycemic level patients with type 2 diabetes (T2DM) with and without Metabolic syndrome (MS). METHODOLOGY: cross sectional study. Included patients randomly DM2 corroborated in your clinical record. The SM was identified in patients with at least 3 of 5 criteria of ATP III (Adult Treatment Panel III). A questionnaire was structured. Hemoglobin was determined (HbA1c), HDL-cholesterol, triglycerides, hypertension (HBP), body mass index (BMI), waist circumference (WC) and hip (NCC). RESULTS: 283 patients were included. Mean age was 59.8 ± 10.6. The predominant sex was female (73.6

). SM Criteria were : low HDL: 62.9

; hypertriglyceridemia: 56.3

; obesity abdominal (OA) 90.1

, hypertension (HBP): 62.5

. The prevalence of MS was 86.6

(95

CI 83

to 89

). There was significant difference in mean HbA1c level in patients with and without MS, HAS, OR, and low HDL. In contrast, subjects with hypertriglyceridemia had an HbA1c level significantly higher than those without hypertriglyceridemia (8.9

2.3 vs 8.5

2.1, respectively, P = 0.01). HbA1c is positively correlated with triglycerides (r = 0.24, p = 0.001), and negatively with weight (r = -0.19, p = 0.001), BMI (r = -0172, p = 0.004), CCI (r = -0.12, P = 0.004) and CCA (r = -0.14, p = 0.02). In adjusted multivariate analysis, only the duration of diabetes was associated with glycemic level (OR = 1.014, 95

in 1.010 to 1.016). CONCLUSIONS: We not found differences significant glycemic level in patients with and without MS.

Comparación del control glucémico en pacientes diabéticos con y sin síndrome metabólico / [Comparison of glycemic control in diabetic patients with and without metabolic syndrome].

OBJECTIVE: To compare the glycemic level patients with type 2 diabetes (T2DM) with and without Metabolic syndrome (MS). METHODOLOGY: cross sectional study. Included patients randomly DM2 corroborated in your clinical record. The SM was identified in patients with at least 3 of 5 criteria of ATP III (Adult Treatment Panel III). A questionnaire was structured. Hemoglobin was determined (HbA1c), HDL-cholesterol, triglycerides, hypertension (HBP), body mass index (BMI), waist circumference (WC) and hip (NCC). RESULTS: 283 patients were included. Mean age was 59.8 ± 10.6. The predominant sex was female (73.6

. The prevalence of MS was 86.6

). There was significant difference in mean HbA1c level in patients with and without MS, HAS, OR, and low HDL. In contrast, subjects with hypertriglyceridemia had an HbA1c level significantly higher than those without hypertriglyceridemia (8.9

2.1, respectively, P = 0.01). HbA1c is positively correlated with triglycerides (r = 0.24, p = 0.001), and negatively with weight (r = -0.19, p = 0.001), BMI (r = -0172, p = 0.004), CCI (r = -0.12, P = 0.004) and CCA (r = -0.14, p = 0.02). In adjusted multivariate analysis, only the duration of diabetes was associated with glycemic level (OR = 1.014, 95

in 1.010 to 1.016). CONCLUSIONS: We not found differences significant glycemic level in patients with and without MS.

Chitosan/poly(DL,lactide-co-glycolide) scaffolds for tissue engineering.

Chitosan/poly(DL-lactide-co-glycolide) (Ch/DL PLG) composite scaffolds were fabricated by freeze-drying lyophilization, and were evaluated and compared for use as a bone regeneration scaffold through measurements of the compression mechanical properties of the porous scaffolds. Also, In vitro cell culture of Sprague-Dawley rat's osteoblasts were used to evaluate the phenotype expression of cells in the scaffolds, characterizing the cellular adhesion, proliferation and alkaline phosphatase activity. The gene expression of osteocalcin, sialoprotein, alkaline phosphatase, Type I collagen and TGFß1 were confirmed in the samples; moreover, it was confirmed, the mineralization by IR spectra and EDS analysis. Our results thus show that Ch/DL PLG scaffolds are suitable for biological applications.

Brownian dynamics simulation of monolayer formation by deposition of colloidal particles: a kinetic study at high bulk particle concentration.

Brownian dynamics simulations (BDS) of sedimentation and irreversible adsorption of colloidal particles on a planar surface were carried out at bulk particle volume fractions (φ) in the range 0.05 to 0.25. The sedimentation and adsorption of colloidal particles were simulated as a non-sequential process that allows simultaneous settling and adsorption of particles. A kinetic model for the formation of particle monolayers based on the available surface fraction (θ(A)) is proposed to predict simulation results. The simulations show a value of 0.625 for the maximum fractional surface coverage (θ(∞)) and a monolayer structure insensitive to φ. However, the kinetic order of the monolayer formation process has a strong dependence with φ, changing from a value close to a unit, at low φ, to a value around two at high φ. This change in the kinetic reaction order is associated to differences of particle adsorption mechanism on the surface. At low φ values, the monolayer formation is achieved by independent adsorption of single particles and the reaction order is close to 1. At high φ values, the simultaneous adsorption of two particles on the surface leads to an increase of the reaction order to values close to 2.

Biological tissues analysis by XRF microtomography.

The main of this work is to determine the elemental distribution in breast and prostate tissue samples in order to verify the concentration of some elements correlated with characteristics and pathology of each tissue observed by the X-ray transmission microtomography (microCT). The experiments were performed at the X-ray fluorescence beamline of the Brazilian Synchrotron Light Laboratory. The microCT images were reconstructed using a filtered-back-projection algorithm and the XRF microtomographies were reconstructed using a filtered-back-projection algorithm with absorption corrections.

Digestive enzymes of eight Amazonian teleosts with different feeding habits.

The levels of amylase, maltase, lipase and alkaline protease from eight fish species of the Amazon were analysed. The enzyme levels are not related to fish feeding habits, reflecting their ever-changing habitats and their opportunistic feeding behaviour.