AbstractA complete characterization of the different physico-chemical properties of nanoparticles (NPs) is necessary for the evaluation of their impact on health and environment. Among these properties, the surface characterization of the nanomaterial is the least developed and in many cases limited to the measurement of surface composition and zetapotential. The biological surface adsorption index approach (BSAI) for characterization of surface adsorption properties of NPs has recently been introduced (Xia et al. Nat Nanotechnol 5:671–675, 2010; Xia et al. ACS Nano 5(11):9074–9081, 2011). The BSAI approach offers in principle the possibility to characterize the different interaction forces exerted between a NP's surface and an organic—and by extension biological—entity. The present work further develops the BSAI approach and optimizes a solid-phase microextraction gas chromatography–mass spectrometry (SPME/GC-MS) method which, as an outcome, gives a better-defined quantification of the adsorption properties on NPs. We investigated the various aspects of the SPME/GC-MS method, including kinetics of adsorption of probe compounds on SPME fiber, kinetic of adsorption of probe compounds on NP's surface, and optimization of NP's concentration. The optimized conditions were then tested on 33 probe compounds and on Au NPs (15 nm) and SiO2 NPs (50 nm). The procedure allowed the identification of three compounds adsorbed by silica NPs and nine compounds by Au NPs, with equilibrium times which varied between 30 min and 12 h. Adsorption coefficients of 4.66 ± 0.23 and 4.44 ± 0.26 were calculated for 1-methylnaphtalene and biphenyl, compared to literature values of 4.89 and 5.18, respectively. The results demonstrated that the detailed optimization of the SPME/GC-MS method under various conditions is a critical factor and a prerequisite to the application of the BSAI approach as a tool to characterize surface adsorption properties of NPs and therefore to draw any further conclusions on their potential impact on health. Graphical AbstractThe basic principle of SPME/GC-MS method for characterization of nanoparticles surface adsorption forces
Introduction Pap smear, the main tool of cervical cancer screening is not always available, but some patients are in urgent need for proper diagnostic. Aim of this article was to investigate accuracy of colposcopy for detection of squamous intraepithelial lesions of low or high grade (LGSIL, HGSIL) and to promote colposcopy as useful tool for detection of patients in need for immediate further diagnostics. Methods Prospective multicentric study performed in BH 95% CI = 42.024 to 5713.304). HGSIL was confirmed in 27 (87%) cases by histology (CIN II /CIN III). There were no statistically significant differences between colposcopic finding and histology results (Yates-corrected χ2 = 0.33 P = .5637) Conclusions This study showed high level of correlation between colposcopy and PAP results (63-64%) and to histology for HGSIL (87%). In absence of PAP test colposcopy could be used to select patients in need for biopsy.
BACKGROUND/AIM The cell line C6 is a continuous cell line of rat glioma and, as a transplantable line, is frequently used for induction into in vivo model of primary brain tumor. It is believed that, pursuant to its histological traits and biological behavior, this experimental tumor corresponds to human anaplastic astrocytoma of grade II/III, which is characterized by proliferative and invasive potency, and marked cell differentiation. The aim of this study was to determine macroscopic analysis of rat brain with implanted tumor during tumorigenesis, histological features of tumor cells of induced brain tumor and markers of proliferation (proliferation cell nuclear antigen - PCNA, cytokeratin - CK 19) and differentiation (glial fibrillary acidic protein -GFAP) in rat brain with implanted tumor. METHODS To determine histological structure of the brain with implanted C6 cells, we used brain sections stained for hematoxylin-eosin or kresyl violet, whereas other sections were immunohistochemically stained for GFAP, CK 19 and PCNA. RESULTS A statistically significant difference in weights of the left and right brain hemispheres with implanted tumors during tumorigenesis in as soon as 7 days from the day of inducing tumors was revealed. The tumor was of cellular type, with distinct pleomorphism of cells and frequent hyperchromasia of the nucleus. Immunohistochemical staining for PCNA revealed a significant number of positive cells on the days 7, 14 and 21 day following the implantation of C6 cells. CK 19 positive cells were present in both brain hemispheres, and numerous GFAP positive astrocytes were found around the puncture lesion. CONCLUSIONS Within the experimental conditions of the present research, C6 glioma did not demonstrate any relevant deviations concerning development, clinical symptomatology and macroscopic anatomy relative to those already described in the literature.
Recent evidence has demonstrated the role of CCR5Δ32 in a variety of human diseases: from infectious and inflammatory diseases to cancer. Several studies have confirmed that genetic variants in chemokine receptor CCR5 gene are correlated with susceptibility and resistance to HIV infection. A 32-nucleotide deletion within the CCR5 reading frame is associated with decreased susceptibility to HIV acquisition and a slower progression to AIDS. Mean frequency of CCR5Δ32 allele in Europe is approximately 10%. The highest allele frequency is observed among Nordic populations (about 12%) and lower in the regions of Southeast Mediterranean (about 5%). Although the frequency of CCR5Δ32 was determined in numerous European populations, there is a lack of studies on this variant in the Bosnia and Hercegovina population. Therefore, the aim of our study was to assess the frequency of CCR5Δ32 allele in the cohort of Bosniaks and compare the results with European reports. CCR5Δ32 was detected by sequence-specific PCR in a sample of 100 healthy subjects from Bosnia and Herzegovina (DNA collected 2011-2013). Mean age of the cohort being 58.8 (± 10.7) years, with 82% of women. We identified 17 heterozygotes and one mutant homozygote in study group, with mean ∆32 allele frequency of 9.5%. CCR5∆32 allele frequency among Bosniaks is comparable to that found in Caucasian populations and follows the pattern of the north-southern gradient observed for Europe. Further studies on larger cohorts with adequate female-to-male ratio are necessary.
Beta lactam antibiotics are widely used in therapy of cattle, particularly for the treatment of mastitis. Over 95% of residue testing in dairies in Bosnia and Herzegovina is for Beta lactams. The aim of this paper is to compare the efficacy of three most common screening tests for Beta lactam residues in cow's milk in our country. The tests used in the study are SNAP β Lactam test (Idexx), Rosa Charm β Lactam test and Inhibition MRL test. Study samples included: standardized concentrations of penicillin solution (0, 2, 3, 4, 5 and 6 ppb). In addition we tested milk samples from three equal size study groups (not receiving any antibiotic therapy, treated with Beta lactams for mastitis and treated with Beta lactams for diseases other than mastitis). Sensitivity and specificity were determined for each test, using standard penicillin concentrations with threshold value set at concentration of 4 ppb (Maximum residue level - MLR). Additionally we determined proportions of presumably false negative and false positive results for each test using results of filed samples testing. Agreement of test results for each test pair was assessed through Kappa coefficients interpreted by Landis-Koch scale. Detection level of all tests was shown to be well below MRL. This alongside with effects of natural inhibitors in milk contributed to finding of positive results in untreated and treated animals after the withholding period. Screening tests for beta lactam residues are important tools for ensuring that milk for human consumption is free from antibiotics residues.
Hypocalcaemia is a state with total calcium serum level below 2.25 mM/l. From the total serum calcium content, 50% is free and ionized, 40% is protein-bound and 10% is bound for organic anions. The most frequent causes of hypocalcaemia are iatrogenic hypoparathyroidism, magnesium deficit, disorders of vitamin D metabolism and chronic renal failure. Iatrogenic hypoparathyroidism is associated with low serum ionized calcium and low serum parathormone levels. There are two important clinical signs of hypocalcemia: Chvostek’s sign (twitches of upper lip after percussion on facial nerve over mandible) and Trousseau’s sign (carpal spasm after increasing pressure in blood pressure cuff placed about the upper arm for 20 milimeters above systolic pressure for 3-5 minutes). The following lab analyses should be performed when hypocalcaemia is an option: serum levels of calcium, magnesium, 25 – hydroxyvitamin, parathormone, potassium, sodium, chloride and bicarbonates. If hypocalcaemia is mild, it could be treated with oral calcium preparations, usually calcium carbonate, in a dose of 1 to 2 grams of elemental calcium daily. In more severe hypocalcaemia intravenous calcium-gluconate or calcium-chloride should be administered, as 10% solutions. These parenteral preparations of calcium should be diluted prior to the intravenous administration, and the administration should be longer than 20 minutes in order to avoid adverse effects on heart. If administration of calcium does not correct hypocalcaemia, oral vitamin D should be also prescribed. If this does not regulate calcaemia, from 0.25 tо 1 micrograms of 1,25-dihydroxyvitamin D (clacitriol) daily should be prescribed. Calcium serum levels should be kept within the lower part of normal serum concentration range.
We present a procedure to simultaneously design the output feedback law and the event-triggering condition to stabilize linear systems. The closed-loop system is shown to satisfy a global asymptotic stability property and the existence of a strictly positive minimum amount of time between two transmissions is guaranteed. The event-triggered controller is obtained by solving linear matrix inequalities (LMIs). We then exploit the flexibility of the method to maximize the guaranteed minimum amount of time between two transmissions. Finally, we provide a (heuristic) method to reduce the amount of transmissions, which is supported by numerical simulations.
The objective is to design output feedback event-triggered controllers to stabilize a class of nonlinear systems. One of the main difficulties of the problem is to ensure the existence of a minimum amount of time between two consecutive transmissions, which is essential in practice. We solve this issue by combining techniques from event-triggered and time-triggered control. The idea is to turn on the event-triggering mechanism only after a fixed amount of time has elapsed since the last transmission. This time is computed based on results on the stabilization of time-driven sampled-data systems. The overall strategy ensures an asymptotic stability property for the closed-loop system. The results are proved to be applicable to linear time-invariant (LTI) systems as a particular case.
O uso desordenado dos recursos resulta por muitas vezes problemas ao meio ambiente. Para um melhor planejamento da superacao de problemas envolvendo o uso excessivo dos recursos naturais, torna-se necessario o conhecimento dos usos que alteram a superficie terrestre. O objetivo deste trabalho foi realizar o mapeamento do uso do solo no modulo IV da Floresta Estadual do Amapa – FLOTA/AP e de areas de seu entorno, bem como identificar seus atores. Para a realizacao da classificacao do uso do solo a partir da classificacao de desmatamento de Silva et al. (2012), foram criadas novas categorias de usos predominantes na area de estudo (mineracao, urbano, agricultura, pecuaria e transporte/comunicacao) no software Envi 4.7, utilizando a chave de identificacao de Anderson et al. (1976) e elementos de fotointerpretacao. Os usos do solo foram classificados, quantificados e identificados os seus atores. Os usos que apresentaram maiores indices de ocupacao na area foram agricultura e pecuaria. Os usos do solo tiveram como principais atores: fazendas, projetos de assentamento agrario e aldeias indigenas. Esses usos se encontram principalmente nas proximidades das estradas oficiais.
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