Adsorption of Organic Dyes on Magnetic Iron Oxide Nanoparticles. Part II: Field-Induced Nanoparticle Agglomeration and Magnetic Separation.

This paper (part II) is devoted to the effect of molecular adsorption on the surface of magnetic iron oxide nanoparticles (IONP) on the enhancement of their (secondary) field-induced agglomeration and magnetic separation. Experimentally, we use Methylene Blue (MB) cationic dye adsorption on citrate-coated maghemite nanoparticles to provoke primary agglomeration of IONP in the absence of the field. The secondary agglomeration is manifested through the appearance of needlelike micron-sized agglomerates in the presence of an applied magnetic field. With the increasing amount of adsorbed MB molecules, the size of the field-induced agglomerates increases and the magnetic separation on a magnetized micropillar becomes more efficient. These effects are mainly governed by the ratio of magnetic-to-thermal energy α, suspension supersaturation Δ0, and Brownian diffusivity Deff of primary agglomerates. The three parameters (α, Δ0, and Deff) are implicitly related to the surface coverage θ of IONP by MB molecules through the hydrodynamic size of primary agglomerates exponentially increasing with θ. Experiments and developed theoretical models allow quantitative evaluation of the θ effect on the efficiency of the secondary agglomeration and magnetic separation.

Thermographic assessment of saddles used in Mangalarga Marchador horses / Avaliação termográfica de selas utilizadas em cavalos da raça Mangalarga Marchador

Poor saddle-fitting is one of the main causes of back pain in horses. Mangalarga Marchador is a popular breed in Brazil, being used mainly for pleasure riding and sports. This study aimed to thermographically assess saddles used in horses of this breed. Thermographic images were obtained from 18 saddles of animals from different categories during a Mangalarga Marchador National Exposition. The evaluation was based on three parameters: contact area symmetry, dorsal midline interaction and total skin contact area (25%, 50%, 75% or 100%). Contact area asymmetry was observed in 83.3% of saddles. Dorsal midline interaction was observed with the same frequency. Only 22.2% of saddles assessed in the present study had panels with contact areas greater than 50%. Based on the results of this essay it can be concluded that thermography is a useful tool for the evaluation of saddle contact area with the back of horses and that there is a high frequency of fitting unconformities in saddles used in Mangalarga Marchador horses.(AU)

O ajuste inadequado da sela é um dos principais causadores de lombalgias em equinos. A raça Mangalarga Marchador está entre as mais populares do Brasil, sendo muito utilizada para cavalgadas e prática de esportes. O presente estudo teve como objetivo avaliar termograficamente as selas utilizadas em cavalos dessa raça. Para tal, foram realizadas imagens termográficas de 18 selas de animais de diversas categorias durante uma Exposição Nacional do Cavalo Mangalarga Marchador. A avaliação foi realizada baseando-se em três parâmetros: simetria da área de contato, interação com a linha média dorsal e área total de contato com a pele (25%, 50%, 75% ou 100%). Em 83,3% das selas avaliadas foi observada assimetria da área de contato. A interação com a linha média dorsal foi observada com a mesma frequência. Apenas 22,2% das selas avaliadas no presente estudo tinham suadouros com área de contato maior que 50%. Com base nos resultados obtidos neste trabalho, conclui-se que a termografia é uma ferramenta útil na avaliação do contato das selas com o dorso dos cavalos e que existe alta frequência de inconformidades no ajuste de selas utilizadas na raça Mangalarga Marchador.(AU)

Two-stage kinetics of field-induced aggregation of medium-sized magnetic nanoparticles.

The present paper is focused on the theoretical and experimental study of the kinetics of field-induced aggregation of magnetic nanoparticles of a size range of 20-100 nm. Our results demonstrate that (a) in polydisperse suspensions, the largest particles could play a role of the centers of nucleation for smaller particles during the earliest heterogeneous nucleation stage; (b) an intermediate stage of the aggregate growth (due to diffusion and migration of individual nanoparticles towards the aggregates) is weakly influenced by the magnetic field strength, at least at high supersaturation;

Effect of particle concentration on the microstructural and macromechanical properties of biocompatible magnetic hydrogels.

We analyze the effect of nanoparticle concentration on the physical properties of magnetic hydrogels consisting of polymer networks of the human fibrin biopolymer with embedded magnetic particles, swollen by a water-based solution. We prepared these magnetic hydrogels by polymerization of mixtures consisting mainly of human plasma and magnetic nanoparticles with OH- functionalization. Microscopic observations revealed that magnetic hydrogels presented some cluster-like knots that were connected by several fibrin threads. By contrast, nonmagnetic hydrogels presented a homogeneous net-like structure with only individual connections between pairs of fibers. The rheological analysis demonstrated that the rigidity modulus, as well as the viscoelastic moduli, increased quadratically with nanoparticle content following a square-like function. Furthermore, we found that time for gel point was shorter in the presence of magnetic nanoparticles. Thus, we can conclude that nanoparticles favor the cross-linking process, serving as nucleation sites for the attachment of the fibrin polymer. Attraction between the positive groups of the fibrinogen, from which the fibrin is polymerized, and the negative OH- groups of the magnetic particle surface qualitatively justifies the positive role of the nanoparticles in the enhancement of the mechanical properties of the magnetic hydrogels. Indeed, we developed a theoretical model that semiquantitatively explains the experimental results by assuming the indirect attraction of the fibrinogen through the attached nanoparticles. Due to this attraction the monomers condense into nuclei of the dense phase and by the end of the polymerization process the nuclei (knots) of the dense phase cross-link the fibrin threads, which enhances their mechanical properties.

Microfluidic separation of magnetic nanoparticles on an ordered array of magnetized micropillars.

Microfluidic separation of magnetic particles is based on their capture by magnetized microcollectors while the suspending fluid flows past the microcollectors inside a microchannel. Separation of nanoparticles is often challenging because of strong Brownian motion. Low capture efficiency of nanoparticles limits their applications in bioanalysis. However, at some conditions, magnetic nanoparticles may undergo field-induced aggregation that amplifies the magnetic attractive force proportionally to the aggregate volume and considerably increases nanoparticle capture efficiency. In this paper, we have demonstrated the role of such aggregation on an efficient capture of magnetic nanoparticles (about 80 nm in diameter) in a microfluidic channel equipped with a nickel micropillar array. This array was magnetized by an external uniform magnetic field, of intensity as low as 6-10 kA/m, and experiments were carried out at flow rates ranging between 0.3 and 30 µL/min. Nanoparticle capture is shown to be mostly governed by the Mason number Ma, while the dipolar coupling parameter α does not exhibit a clear effect in the studied range, 1.4 < α < 4.5. The capture efficiency Λ shows a strongly decreasing Mason number behavior, Λ∝Ma^{-1.78} within the range 32 ≤ Ma ≤ 3250. We have proposed a simple theoretical model which considers destructible nanoparticle chains and gives the scaling behavior, Λ∝Ma^{-1.7}, close to the experimental findings.

Daily oscillations of skin temperature in military personnel using thermography.

INTRODUCTION: The human body makes many physiological adjustments throughout the day, including adjustments to body temperature. The purpose of this study was to determine oscillations in the skin temperature (Tsk-1-Tsk-25) at 25 body regions of interest (ROIs) over 1 day using infrared thermography. METHODS: Tsk values of 31 male (age 22.9±3.0 years) Brazilian Air Force members were evaluated from five thermograms collected at 7, 11, 15, 19 and 23 h (Tsk7,11,15,19,23) by a Fluke imager. We applied one-way analysis of variance for repeated measures for the different times of the day and Tukey's post hoc test to determine significant Tsk differences between ROIs (α=0.05), and the cosinor analysis was used to determine the midline estimating statistic of rhythm, amplitude and acrophase of Tsk during the 24 h period. RESULTS: The anterior hands showed the greatest Tsk variations throughout the day. In the lower limbs, scapula, abdomen, chest and lower back, Tsk-11, Tsk-15, Tsk-19 and Tsk-23 were significantly different (p<0.05) from Tsk-7. The lowest Tsk values were obtained in the early morning, with increases in the afternoon and levelling after 15:00. CONCLUSIONS: The Tsk at all ROIs and the averaged Tsk showed oscillations throughout the day, with the lowest values in the early morning (07:00). Temperature fluctuations depended on the specific ROI, with thermal stabilisation in some regions in the afternoon and a central upward trend throughout the day in the hands.

The temperature of water ingested ad libitum does not influence performance during a 40-km self-paced cycling trial in the heat.

AIM: The aim of the present study was to evaluate the effects of the temperature of ingested water on performance during a 40-km self-paced cycling trial in the heat (35º C and 60% relative humidity). METHODS: The study was randomized, counterbalanced, crossover and single-blinded. Ten well-trained male cycling athletes (cyclists, mountain bikers or triathletes) who were non-acclimatized to heat were subjected to four experimental situations divided into two sets. In the first set, the participants performed two trials, during which they were given either cold (10º C) or warm water (37º C) ad libitum. In these situations, the volume and timing of the water ingestion (when each bolus was ingested) were recorded and replicated in the second set, but the water temperature was reversed. RESULTS: The performance times were unaffected by the water intake volume (P=0.425), but the water at a temperature of 37º C tended to induce lower performance times (P=0.078) during the trials (AL10=93.0±3.5 min; AL37=94.4±4.1 min; SC10=93.4±4.0; SC37=97.4±4.3 min). The water intake was greater when the water was cold (P<0.05), but the temperature did not affect the heat storage rate, rectal temperature, mean skin temperature, heart rate, blood glucose level, sweat loss, sweat rate, perceived exertion rate or plasma volume changes. However, a significant reduction in the plasma volume change from pre- to postexercise was observed (P<0.01). CONCLUSION: The performance, thermoregulatory, cardiovascular and metabolic responses during a 40-km self-paced cycling trial in the heat were unaffected by different water temperatures.

The role of water intake on cardiac vagal reactivation after upper-body resistance exercise.

The aim of this study was to assess the hypothesis that water intake will accelerate cardiac vagal reactivation after a single session of upper-body resistance exercise. 13 healthy men (26.5±5.9 years) with previous experience in resistance training were enrolled. In visits 1 and 2, participants performed the one-repetition maximum (1RM) test and retest with the bench press exercise. The sessions 3 and 4 were performed randomly, while participants consumed 500 ml (experimental visit) or 50 ml (control visit) of water immediately after 3 sets of maximum repetitions at 80% of 1RM. Cardiac vagal activity was represented by cardiac vagal index (CVI) measured before, immediately after and 30 min post-exercise. Additionally, heart rate and blood pressure were measured. The results show that CVI was higher 30 min post-exercise when 500 ml of water was ingested compared to 50 ml (1.39±0.07 vs. 1.23±0.07; p=0.02) (mean±SEM). Heart rate and blood pressure values were similar in both trials. We conclude that water intake accelerates post-resistance exercise cardiac vagal reactivation. These findings suggest that hydration after resistance exercise might be beneficial for cardiovascular safety in healthy subjects.

Cytocompatibility of the ready-to-use bioceramic putty repair cement iRoot BP Plus with primary human osteoblasts.

AIM: To verify the in vitro cytocompatibility of iRoot BP Plus (iRoot) and to compare it with White ProRoot MTA (MTA). METHODOLOGY: Thirty-six human maxillary incisor root canals were prepared using a step-back flaring technique. The apical 3 mm was resected perpendicular to the long axis at the roots, and root-end cavities were prepared with the aid of an ultrasonic device plus a diamond retrotip with continuous irrigation using water, producing standardized preparations. After that, the root-end cavities were filled with iRoot or MTA, and each root was exposed to cell culture media for 24 or 48 h. Human osteoblast cells were exposed to the extracts thus obtained, and a multiparametric cell viability assay was performed, evaluating mitochondrial activity, membrane integrity and cell density. The results were analysed by one-way analysis of variance, complemented with the Duncan post-test (P < 0.05). RESULTS: Cells exposed to MTA revealed a cytocompatibility pattern similar to the untreated cells (negative control), at both experimental times (P > 0.05). iRoot, however, promoted a significantly poorer viability than MTA and the control, after 48 h of exposure (P < 0.001). Nevertheless, iRoot did not induce critical cytotoxic effects because cell viability remained higher than 70% of the control group in most tests performed. CONCLUSION: iRoot and MTA were biocompatible and did not induce critical cytotoxic effects.

Methods of body mass reduction by combat sport athletes.

The aim of this study was to investigate the methods adopted to reduce body mass (BM) in competitive athletes from the grappling (judo, jujitsu) and striking (karate and tae kwon do) combat sports in the state of Minas Gerais, Brazil. An exploratory methodology was employed through descriptive research, using a standardized questionnaire with objective questions self-administered to 580 athletes (25.0 ± 3.7 yr, 74.5 ± 9.7 kg, and 16.4% ± 5.1% body fat). Regardless of the sport, 60% of the athletes reported using a method of rapid weight loss (RWL) through increased energy expenditure. Strikers tend to begin reducing BM during adolescence. Furthermore, 50% of the sample used saunas and plastic clothing, and only 26.1% received advice from a nutritionist. The authors conclude that a high percentage of athletes uses RWL methods. In addition, a high percentage of athletes uses unapproved or prohibited methods such as diuretics, saunas, and plastic clothing. The age at which combat sport athletes reduce BM for the first time is also worrying, especially among strikers.

Smear layer dissolution by peracetic acid of low concentration.

AIM: To test the effect of a noncaustic concentration of peracetic acid (PAA) in a standardized smear layer model. METHODOLOGY: The smear layer dissolution kinetics of 0.5% PAA on human dentine were compared to those of 2.25% PAA and 17% ethylenediaminetetraacetic acid (EDTA) solutions. Coronal dentine discs were prepared from six human maxillary molars. A standardized smear layer was produced on the pulpal side of each disc. The smear layer-covered surface was divided into three similar areas and then exposed to one of the three solutions tested. Co-site image sequences (around 40, 500 ×) of the specific areas were obtained after four cumulative demineralisation times (15, 30, 60 and 180 s). An image processing and analysis sequence measured sets of images, providing data of area fraction (AF, dentine-free area in % of total analysis area). A general linear model for repeated measures was used to verify the influence of time and solution type over the change in AF from baseline (ΔAF). RESULTS: Overall, EDTA and 2.25% PAA produced higher ΔAF values than the 0.5% PAA solution (P < 0.05). No significant difference was observed in ΔAF between 15 s and 30 s (P > 0.05). After 60 s of etching, all tested solutions produced similar ΔAF (P > 0.05), whereas at 180 s, ΔAF of both EDTA and 2.25% PAA continued to increase (P > 0.05). CONCLUSIONS: After 60 s of contact, the 0.5% PAA solution dissolved smear layer as well as 2.25% PAA and 17% EDTA.

Hábitos de hidratación en un colectivo de deportistas de pruebas de resistencia / Hydratation habits in an endurance athletes group

El objeto de nuestra investigación fue verificar el conocimiento que los deportistas tienen sobre la hidratación y el uso que hacen del mismo. El estudio se realizó en un colectivo de deportistas de resistencia compuesto por 114 triatletas (85 hombres y 29 mujeres), 123 corredores de fondo (100 hombres y 23 mujeres) y ciclistas (100 hombres). Se elaboró una encuesta compuesta de un total de 13 preguntas sobre temas que relacionan el ejercicio y la hidratación. Los resultados indican que no hidratar tanto en competiciones como entrenamientos es una práctica habitual en 11,3 por ciento de los corredores de fondo, 2,6 por ciento de los triatletas y 5,1 por ciento de los ciclistas. Las señales de deshidratación más registradas tanto en los triatletas como en los corredores de fondo y ciclistas fueron: a) sed muy intensa; b) fatiga física generalizada y c) sensación de pérdida de fuerza. Llegamos a la conclusión de que hay necesidad de establecer campañas de información sobre la importancia de la hidratación entre los deportistas de las tres pruebas, principalmente entre los corredores de fondo (AU)

[Meningiomas of the cavernous sinus: the surgical resectability and complications]. / Meningiomas do seio cavernoso: correlação entre a extensão de ressecção cirúrgica e lesões neurovasculares em 16 pacientes.

The optimal management for patients with cavernous sinus meningiomas is to evacuate tumor without causing mortality or morbidity. The records of 16 patients, including 11 women and 5 men ranging in age from 31 to 63 years, underwent surgical treatment for this condition were reviewed. Completeness of tumor resection, cranial nerve morbidity, complications, mortality, the internal carotid artery encasement and outcome were studied. Total removal was achieved in six patients. Of ten patients who underwent subtotal resection there was one death and four were sent to radiotherapy. Morbidity was 24% for cranial nerves controlling extraocular motor function; trigeminal nerve function did not improve after surgical treatment. Symptomatic recurrence occurred in two patients who underwent subtotal tumor resection and in one who underwent complete tumor resection. The average follow-up period was of 26 months. According to our findings, we conclude: 1) the resectability of meningiomas of cavernous sinus depends on the degree of internal carotid artery involvement; 2) total resection of meningiomas confined in cavernous sinus is rare; 3) morbidity of the cranial nerves is significant; 4) subtotal resection is an effective mean to obtain control of the disease.

Deshidratación y ejercicio físico / Dehydration and exercise

La deshidratación durante el ejercicio representa uno de los principales factores que limitan el rendimiento físico: Por el contrario, una perfecta hidratación, antes, durante y después del ejercicio, mejorará el rendimiento, no solamente en la competición, si no también en los largos períodos de entrenamiento. Un mayor conocimiento sobre el tema por medio del conjunto de profesionales que actúan en el deporte, además de ayudar al deportista, puede concienciarlo sobre la importancia del consumo de líquidos. Este artículo pretende, presentar las características básicas de un cuadro de deshidratación, su etiología, fisiopatología, formas de evaluar un cuadro de deshidratación, además de su relación con la actividad física y las consecuencias que tiene en el rendimiento. Se trataran también aquellas funciones que no sufren interferencia con la deshidratación (AU)

Heat shock attenuates oxidation and accelerates apoptosis in human neutrophils.

BACKGROUND: The heat shock response entails the increased expression of heat shock proteins (hsp) which are capable of protecting cells from subsequent metabolic insults. Here we are interested in determining whether activation of the heat shock response might affect polymorphonuclear leukocyte (PMN) function and/or longevity. METHODS: Freshly isolated human PMN were either left at 37 degrees C or subjected to a 43 degrees C heat shock treatment (60 min) and subsequently returned to 37 degrees C. During the course of the recovery period a number of parameters were examined for the control and heat shock-treated neutrophils: the relative expression of the highly stress-inducible hsp72; respiratory burst activity as measured by intracellular peroxidation in response to phorbol ester addition; cell-surface expression of CD16; and finally, the extent of apoptosis as determined by both annexin V staining and nuclear propidium iodide staining. RESULTS: Heat shock treatment resulted in a progressive increase in hsp72 production, peaking at 8 h following return of the cells to 37 degrees C. Net intracellular oxidant production was diminished by 46% immediately following the heat shock treatment and deteriorated even further over the next 4 h. Finally, a significant early increase in the rate of apoptosis was observed in the cells subjected to the hyperthermic treatment. This increase in the heat-induced rate of apoptosis was associated with a marked reduction in cell-surface CD16 levels. CONCLUSIONS: By decreasing PMN oxidative functions and by accelerating their apoptotic demise, it would appear that heat shock is anti-inflammatory and not cytoprotective for PMN.

[Giant intracranial aneurysm in a 9 year-old child. Case report]. / Aneurisma intracraniano gigante em criança de nove anos. Relato de caso.

The case of a 9-year-old girl with intracranial hemorrhage due to a giant aneurysm of distal middle cerebral artery is reported. Cerebral aneurysms are rare in children, particularly in the first decade of life. Aneurysms in childhood occur more frequently in peripheral branches and they are more often giant in size. Clinical features and pathogenesis of this lesion are discussed.

[Unusual association of Kallmann syndrome and arachnoid cyst of the middle fossa. Report of a case]. / Associação singular de síndrome de Kallmann e cisto aracnóide da fossa média. Relato de caso.

Hypogonadotrophic hypogonadism can result from different abnormalities in the central nervous system. The clinical picture depends upon the time of onset the deficiency, the magnitude of the gonadotropins deficiency and whether there are other pituitary hormone deficiencies as well. We report on a 18-year-old boy, who was investigated because of pubertal and growth delay. He also had learning disabilities. On physical examination he exhibited mild eunuchoid aspect, 162 cm height (z score = 2.17), pubertal development on stage G II, P II, and 4 cm3 testis. Laboratory investigation revealed pre-pubertal levels of testosterone and normal results of the combined test of anterior pituitary function, except for in GnRH acute and prolonged test. Brain CT showed an arachnoid cyst on left middle fossa with expansion to suprasellar cisterna. He was diagnosed as having hypogonadotrophic hypogonadism secondary to compression by the cyst, and a cyst-peritoneal derivation was performed. After surgery there was no improvement of the pubertal state and bilateral anosmia was discovered, so Kallmann's syndrome was then diagnosed and was confirmed by MRI, even though the hormonal results are not totally matched with the referred syndrome. We did not find in the literature any description of the association between Kallmann's syndrome and arachnoid cyst and we believe that in this case the results of the hormonal measurement may be due to such association that provoked an additional hypophysis dysfunction.

Papiloma invertido: aspectos radiográficos / Inverted papiloma: radiologic findings

O papiloma invertido é um tumor epitelial incomum que compromete a regiäo nasal e os seios paranasais. Este tumnor, embora originariamente benigno, tem alto grau de recorrência, podendo sofrer transformaçäo maligna. Ele pode destruir estruturas ósseas e se estender para as fossas cranianas anteriores e média, e tornar-se, desse modo, indistinguível radiologicamente de lesäo malígna. 8 pacientes com papiloma invertido histologicamente confirmados säo descritos e os seus achados radiológicos apresentados e comparados com os da literatura

Sonographic findings of adrenal cortical carcinomas in children.

Fourteen children with adrenal cortical carcinoma were evaluated by ultrasonography. The neoplasms, 2.5 cm-19 cm in maximum diameter, were all well circumscribed. The four smaller lesions were either homogeneously hypoechoic (2 patients) or generally hyperechoic (2 patients). In the 10 patients with larger tumors, a complex predominantly echogenic pattern was demonstrated, eight of which contained radiating linear echoes, the "scar sign". This finding, although not specific, when present in a large adrenal mass, is suggestive of a cortical carcinoma. Associated findings of vascular invasion or retroperitoneal adenopathy supported the diagnosis of a malignant adrenal neoplasm in 3 patients.

Sonographic features of benign intraperitoneal lipomatous tumors in children--report of 4 cases.

Four children with benign intraperitoneal lipomatous tumors (mesenteric lipoma, mesenteric lipoblastoma, omental lipoblastoma and mesenteric mesenchymoma) are reported. The ultrasonographic findings of these unusual pediatric masses are described and correlated with their conventional radiologic and pathologic appearance. The pre-operative diagnosis of these entities can be suggested by these features.