Tuning the order of colloidal monolayers: assembly of heterogeneously charged colloids close to a patterned substrate

We study the behavior of negatively charged colloids with two positively charged polar caps close to a planar patterned surface. The competition between the different anisotropic components of the particle-particle interaction patterns is able by itself to give rise to a rich assembly scenario: colloids with charged surface patterns form different crystalline domains when adsorbed to a homogeneously charged substrate. Here we consider substrates composed of alternating (negative/neutral, positive/neutral and positive/negative) parallel stripes and, by means of Monte Carlo simulations, we investigate the ordering of the colloids on changing the number of the stripes. We show that the additional competition between the two different lengths scales characterizing the system ($i.e.,$ the particle interaction range and the size of the stripes) gives rise to a plethora of distinct particle arrangements, where some well-defined trends can be observed. By accurately tuning the substrate charged motif it is possible to, $e. g.,$ promote specific particles arrangements, disfavor crystalline domains or induce the formation of extended, open clusters.Comment: 18 pages, 15 figure

Myelodysplastic syndromes: the pediatric point of view.

Myelodysplastic syndromes (MDS) are clonal disorders of the multipotent hematopoietic stem cell characterized by ineffective hematopoiesis and associated with marrow hypercellularity, increased intramedullary cell death and peripheral cytopenias of varying severity. Patients with myelodysplasia have a propensity (20% to 30% of cases) to undergo transformation into acute myeloid leakemia (AML), and a large body of evidence indicates that MDS represent steps in the multiphasic evolution of AML. Progression of the disease is characterized by expansion of the abnormal clone and inhibition of normal hematopoiesis leading to deterioration of the blood cell count and/or development of AML. MDS are relatively unusual in childhood, representing only 3% of pediatric hematological malignancies, although it has been reported that up to 17% of pediatric AML cases may have a previous myelodysplastic phase. The first systematic attempt at morphological classification of MDS was provided by the French-American-British (FAB) group. However, the FAB classification of MDS is only partially applicable in children. Some variants are extremely rare or absent (refractory anemia with ring sideroblasts and chronic myelomonocytic leukemia), and other peculiar pediatric disorders, represented by juvenile chronic myelogenous leukemia (JCML) and the monosomy 7 syndrome, are not included. Moreover, since there is a partial overlap between pediatric MDS and myeloproliferative disorders and the variants occurring in young children have rather specific features, some confusion still surrounds the nosographical definition of childhood MDS, so that none of the proposed classifications are widely accepted and used. Characteristically, some genetic conditions such as Fanconi's anemia, Shwachman's and Down's syndromes predispose to the development of MDS in childhood. The most common variants of childhood MDS are represented by JCML and the monosomy 7 syndrome, both disorders typically occurring in young children. JCML is characterized by a spontaneous growth of granulocyte-macrophage progenitors that show a striking hypersensitivity to granulocyte-macrophage colony-stimulating factor. Clinical presentation resembles that of some myeloproliferative disorders, with massive organomegaly usually not observed in the classically reported variants of MDS. Clinical features of the monosomy 7 syndrome resemble those observed in JCML and a differential diagnosis between these two entities relies upon the higher percentage of fetal hemoglobin, the more pronounced decrease in platelet count and, in some cases, the lack of the peculiar cytogenetic abnormality in the latter. With the number of children being cured of cancer constantly rising, a significant increase in secondary or chemotherapy-related myelodysplasia is being observed, and these disorders represent a formidable challenge for pediatric hematologists due to their poor response to chemotherapy. As a matter of fact, owing to their biological heterogeneity and aggressive clinical course in childhood, all MDS variants pose serious difficulties for successful management. If a compatible donor is available, allogeneic bone marrow transplantation (BMT) becomes the treatment of choice and should be performed during the early stages of the disease. Supportive therapy, differentiative treatments and low-dose chemotherapy, while valuable alternative therapeutic options in adults, have limited application in pediatric patients. The role of intensive chemotherapy and autologous BMT has not yet been clearly defined, and the use of hematopoietic growth factors does not seem to have a significant influence on the natural history of the disease. In the future, new insights into the events leading to progressive genetic changes in the clonal population and into the molecular basis of these genetic lesions could result in interesting new therapeutic approaches directed either at the oncogenes involved in the pathogenesis of the disease, or at the cytokines and/or their receptors causing the abnormal differentiation and proliferation of the myelodysplastic clone

Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants

<p>Abstract</p> <p>Background</p> <p>Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between <it>Lactobacillus </it>spp. strains and gas-forming coliforms isolated from stools of colicky infants.</p> <p>Results</p> <p>Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for <it>Enterobacteriaceae</it>. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76) log₁₀<it>vs </it>3.90 (2.50-7.10) CFU/g of faeces (p = 0.015). The following strains were identified: <it>Escherichia coli</it>, <it>Klebsiella pneumoniae</it>, <it>Klebsiella oxytoca</it>, <it>Enterobacter aerogenes</it>, <it>Enterobacter cloacae </it>and <it>Enterococcus faecalis</it>. Then, 27 <it>Lactobacillus </it>strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. <it>Lactobacillus delbrueckii </it>subsp.<it>delbrueckii </it>DSM 20074 and <it>L. plantarum </it>MB 456 were able to inhibit all coliforms strains (halo-forming method), also in liquid co-cultures, thus demonstrating an antagonistic activity.</p> <p>Conclusions</p> <p>This study shows that two out of 27 strains of <it>Lactobacillus </it>examined possess an antimicrobial effect against six species of gas-forming coliforms isolated from colicky infants. Our findings may stimulate new researches to identify which <it>Lactobacillus </it>strains can improve colicky symptoms by acting on coliforms gut colonization.</p

Esophageal Bolus Transit in Newborns with Gastroesophageal Reflux Disease Symptoms: A Multichannel Intraluminal Impedance Study.

PURPOSE: The aim of this study was to evaluate bolus transit during esophageal swallow (ES) and gastroesophageal reflux (GER) events and to investigate the relationship between the characteristics of ES and GER events in a population of term and preterm newborns with symptoms of gastroesophageal reflux disease (GERD). METHODS: The study population consisted of term and preterm newborns referred to combined multichannel intraluminal impedance (MII) and pH monitoring for GERD symptoms. The frequency and characteristics of ES and GER events were assessed by two independent investigators. Statistical significance was set at p<0.05. RESULTS: Fifty-four newborns (23 preterm) were included in the analyses. Median bolus head advancing time corrected for esophageal length (BHATc) was shorter during mealtime than during the postprandial period (median, interquartile range): 0.20 (0.15-0.29) s/cm vs. 0.47 (0.39-0.64) s/cm, p<0.001. Median bolus presence time (BPT) was prolonged during mealtime: 4.71(3.49-6.27) s vs. 2.66 (1.82-3.73) s, p<0.001. Higher BHATc (p=0.03) and prolonged BPT (p<0.001) were observed in preterm newborns during the postprandial period. A significant positive correlation between BHATc and bolus clearance time was also observed (ρ=0.33, p=0.016). CONCLUSION: The analysis of ES and GER events at the same time by MII provides useful information to better understand the physiopathology of GERD. In particular, the analysis of BHATc during the postprandial period could help clinicians identify newborns with prolonged esophageal clearance time due to impaired esophageal motility, which could allow for more accurate recommendations regarding further tests and treatment

A influência de difernetes tipos de cobertura no conforto térmico em habitações no município de nova Xavantina-MT / Influence of different types of coverage in thermal comfort in houses in the municipality of nova Xavantina-MT

O município de Nova Xavantina - MT possui temperaturas elevadas, essas temperaturas são consequências do clima tropical. Posto isso, demonstra-se a necessidade de estudos voltados a fim de amenizar a temperatura no interior das construções, com a finalidade de se obter um ambiente satisfatório para aqueles que nele habitam. Por isso, novos materiais são desenvolvidos buscando melhorar a temperatura interna das construções, contudo, tais materiais superam as características térmicas dos materiais usuais? Diante disso, realizou-se uma pesquisa de caráter qualitativo-quantitativo, por meio da coleta e análise de dados de diferentes tipos de cobertura, para verificar se houve diferença entre os materiais isolantes e os comuns. Quatro protótipos idênticos de 1,0x0,5x0,7 metros foram construídos em alvenaria comum, diferindo apenas no material de cobertura. Foram usadas as seguintes telhas: telha PVC, telha cerâmica romana, telha sanduíche, e telha fibrocimento com manta térmica. Optou-se para essa pesquisa as telhas, por serem as principais receptoras das radiações solares nas construções. Concluiu-se que os materiais isolantes além de diminuir a temperatura interna, corroboram com uma melhor umidade relativa no interior das construções, entretanto, os materiais isolantes possuem um custo elevado comparado aos convencionais devido à falta de procura no mercado.

Análise comparativa entre o sistema contrutivo concreto pvc e alvenaria convencional utilizadas em construções de habitações de interesse social / Comparative analysis between the concrete pvc concrete system and conventional masonry used in construction of housing of social interest

As condições habitacionais precárias do Brasil se encontram em situação alarmante há anos, apresentando dados de déficit habitacional cada vez mais crescente, seja por condições inadequadas de moradias, por localização em zonas de risco, por famílias de baixa renda que tem que pagar aluguel e até mesmo por pessoas que se instalam nas ruas dos centros urbanos. A alta demanda decorrente desse problema social requer a utilização de sistemas construtivos eficientes, produtivos, econômicos, seguros, duráveis e racionalizados, como é o caso de sistemas industrializados, como o concreto PVC, que apresenta uma produtividade oito vezes maior que o método convencional. O objetivo desse estudo é realizar um comparativo entre o método de construção convencional e o Concreto PVC como potenciais técnicas para aplicação nesse tipo de habitação. O estudo possui abordagem qualitativa do tipo aplicada exploratória, sendo realizada através de pesquisa bibliográfica, onde foram reunidas informações sobre ambos os métodos e apresentados de forma comparativa. Os dados coletados foram analisados através da fundamentação teórica apresentada, permitindo a comparação indutiva dos sistemas analisados para aplicação em HIS. A análise verificou que o concreto PVC oferece todas as características essenciais para construção de HIS, apresentando maiores benefícios que o método tradicionalmente utilizado, a alvenaria comum, podendo ser considerada ideal para esse tipo de utilização

Iron overload enhances human mesenchymal stromal cell growth and hampers matrix calcification

Background Iron overload syndromes include a wide range of diseases frequently associated with increased morbidity and mortality. Several organs are affected in patients with iron overload including liver, heart, joints, endocrine glands, and pancreas. Moreover, severe bone and hemopoietic tissue alterations are observed. Because of the role of bone marrow mesenchymal stromal cells (BM-MSCs) in bone turnover and hematopoiesis, iron effects on primary BM-MSCs cultures were evaluated. Methods Primary human BM-MSCs cultures were prepared and the effects of iron on their proliferation and differentiation were characterized by biochemical analyses and functional approaches. Results Addition of iron to the culture medium strongly increased BM-MSCs proliferation and induced their accelerated S phase entry. Iron enters BM-MSCs through both transferrin-dependent and transferrin-independent mechanisms, inducing the accumulation of cyclins E and A, the decrease of p27Kip1, and the activation of MAPK pathway. Conversely, neither apoptotic signs nor up-regulation of reactive oxygen species were observed. Iron inhibited both differentiation of BM-MSCs into osteoblasts and in vitro matrix calcification. These effects result from the merging of inhibitory activities on BM-MSCs osteoblastic commitment and on the ordered matrix calcification process. Conclusions We demonstrated that BM-MSCs are a target of iron overload. Iron accelerates BM-MSCs proliferation and affects BM-MSCs osteoblastic commitment, hampering matrix calcification. General Significance Our study reports, for the first time, that iron, at concentration found in overloaded patient sera, stimulates the growth of BM-MSCs, the BM multipotent stromal cell component. Moreover, iron modulates the physiological differentiation of these cells, affecting bone turnover and remodeling

Glutathione S-transferase homozygous deletions and relapse in childhood acute lymphoblastic leukemia: a novel study design in a large Italian AIEOP cohort

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Proliferation of Transformed Somatotroph Cells Related to Low or Absent Expression of Protein Kinase A Regulatory Subunit 1A Protein

Abstract The two regulatory subunits (R1 and R2) of protein kinase A (PKA) are differentially expressed in cancer cell lines and exert diverse roles in growth control. Recently, mutations of the PKA regulatory subunit 1A gene (PRKAR1A) have been identified in patients with Carney complex. The aim of this study was to evaluate the expression of the PKA regulatory subunits R1A, R2A, and R2B in a series of 30 pituitary adenomas and the effects of subunit activation on cell proliferation. In these tumors, neither mutation of PRKAR1A nor loss of heterozygosity was identified. By real-time PCR, mRNA of the three subunits was detected in all of the tumors, R1A being the most represented in the majority of samples. By contrast, immunohistochemistry documented low or absent R1A levels in all tumors, whereas R2A and R2B were highly expressed, thus resulting in an unbalanced R1/R2 ratio. The low levels of R1A were, at least in part, due to proteasome-mediated degradation. The effect of the R1/R2 ratio on proliferation was assessed in GH3 cells, which showed a similar unbalanced pattern of R subunits expression, and in growth hormone-secreting adenomas. The R2-selective cAMP analog 8-Cl cAMP and R1A RNA silencing, stimulated cell proliferation and increased Cyclin D1 expression, respectively, in human and rat adenomatous somatotrophs. These data show that a low R1/R2 ratio promoted proliferation of transformed somatotrophs and are consistent with the Carney complex model in which R1A inactivating mutations further unbalance this ratio in favor of R2 subunits. These results suggest that low expression of R1A protein may favor cAMP-dependent proliferation of transformed somatotrophs