Collective behavior in nuclear interactions and shower development

The mechanism of hadronic interactions at very high energies is still unclear. Available accelerator data constrain weakly the forward rapidity region which determines the development of atmospheric showers. This ignorance is one of the main sources of uncertainty in the determination of the energy and composition of the primary in hadron-induced atmospheric showers. In this paper we examine the effect on the shower development of two kinds of collective effects in high-energy hadronic interactions which modify the production of secondary particles. The first mechanism, modeled as string fusion, affects strongly the central rapidity region but only slightly the forward region and is shown to have very little effect on the shower development. The second mechanism implies a very strong stopping; it affects modestly the profile of shower maximum but broadens considerably the number distribution of muons at ground. For the latter mechanism, the development of air showers is faster mimicking a heavier projectile. On the other hand, the number of muons at ground is lowered, resembling a shower generated by a lighter primary.Comment: 17 pages, 10 figure

Avaliação da atividade antioxidante e citotóxico in vitro do óleo essencial de curcuma zedoaria (christm.) Roscoe / Evaluation of in vitro antioxidant and cytotoxic activity of curcuma zedoaria (christm.) Roscoe Essential oil

Curcuma zedoaria (Christm.) Roscoe é uma planta herbácea e rizomatosa da família Zingiberaceae. As folhas e os rizomas do gênero Curcuma são fontes de óleos essenciais utilizados na indústria química, farmacêutica e de alimentos devido a sua ação antioxidante. O óleo essencial de Curcuma zedoaria possui potente atividade citotóxica, antioxidante e inibe a proliferação celular de diversos tipos de cânceres. Apesar da sua importância biológica e econômica verificamos ausência na literatura de ensaios in vitro com método de difusão em culturas de Escherichia coli BW9091 e AB1157 sob a ação de agentes oxidantes (SnCl2 e H2O2) que atacam o DNA cromossômico e nucleotídeos livres e de estudos que descrevam a ação do óleo essencial com o antibiótico amoxicilina. Vale ressaltar que as cepas Escherichia coli AB1157 e BW9091 apresentam, respectivamente, todos os mecanismos de reparos funcionantes para o reparo de DNA e uma deficiência na exonuclease III (xthA-), isto é, deficiência nos sistemas envolvidos na correção de danos oxidativos do DNA por excisão de bases (BER). Já o antibiótico amoxicilina tem mobilizado a atenção e preocupação em serviços hospitalares devido ao aumento de casos de resistência microbiana. Verificou-se, neste estudo que óleo essencial de Curcuma zedoaria inibiu as cepas Escherichia coli BW9091 nas concentrações de 12 e 24 L. Contudo, a diferença na concentração foi, ligeiramente, mais perceptiva em Escherichia coli AB1157 (p<0,001) do que com a Escherichia coli BW9091 (p<0,01). É provável que a presença do gene mutante na cepa Escherichia coli BW9091 tenha promovido um aumento da resistência ao efeito inibitório do óleo essencial. Verificamos que o óleo essencial de Curcuma zedoaria nas concentrações de 24 e 12 µL apresentou potencial inibitório em ambas as cepas de Escherichia coli. Verificou-se, em Escherichia coli AB 1157, que a associação entre o óleo essencial e amoxicilina na concentração de 12 µL apresentou um halo de inibição maior do que quando administrado com o antibiótico isolado. O teste Turkey Kramer demonstrou que houve uma diferença significativa (p<0.001) entre as médias desses halos. A associação de óleo essencial com o cloreto estanoso 12 µL teve seu efeito citotóxico potencializado com ambas as cepas. Entretanto, em Escherichia coli AB 1157 o halo de inibição foi menor, demonstrando que o óleo essencial pode exercer um efeito sinérgico quando associado ao cloreto estanoso. Vale a pena ressaltar que essas diferenças foram significativas (p<0.01) tanto para a Escherichia coli AB1157 e BW9091. Já no controle positivo do peróxido de hidrogênio (H2O2) + 12 µL do óleo essencial observamos aumento na ação oxidativa na cepa AB1157. Portanto, concluímos que o óleo essencial tem potencial farmacológico como princípio ativo natural; exerceu atividades antioxidante e antimicrobiana sobre as cepas de Escherichia coli testadas e potencializou o efeito inibitório quando associado ao antibiótico amoxicilina

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

Sensitization of cervix cancer cells to Adriamycin by Pentoxifylline induces an increase in apoptosis and decrease senescence

<p>Abstract</p> <p>Background</p> <p>Chemotherapeutic drugs like Adriamycin (ADR) induces apoptosis or senescence in cancer cells but these cells often develop resistance and generate responses of short duration or complete failure. The methylxantine drug Pentoxifylline (PTX) used routinely in the clinics setting for circulatory diseases has been recently described to have antitumor properties. We evaluated whether pretreatment with PTX modifies apoptosis and senescence induced by ADR in cervix cancer cells.</p> <p>Methods</p> <p>HeLa (HPV 18+), SiHa (HPV 16+) cervix cancer cells and non-tumorigenic immortalized HaCaT cells (control) were treated with PTX, ADR or PTX + ADR. The cellular toxicity of PTX and survival fraction were determinated by WST-1 and clonogenic assay respectively. Apoptosis, caspase activation and ADR efflux rate were measured by flow cytometry, senescence by microscopy. IκBα and DNA fragmentation were determinated by ELISA. Proapoptotic, antiapoptotic and senescence genes, as well as HPV-E6/E7 mRNA expression, were detected by time real RT-PCR. p53 protein levels were assayed by Western blot.</p> <p>Results</p> <p>PTX is toxic (WST-1), affects survival (clonogenic assay) and induces apoptosis in cervix cancer cells. Additionally, the combination of this drug with ADR diminished the survival fraction and significantly increased apoptosis of HeLa and SiHa cervix cancer cells. Treatments were less effective in HaCaT cells. We found caspase participation in the induction of apoptosis by PTX, ADR or its combination. Surprisingly, in spite of the antitumor activity displayed by PTX, our results indicate that methylxantine, <it>per se </it>does not induce senescence; however it inhibits senescence induced by ADR and at the same time increases apoptosis. PTX elevates IκBα levels. Such sensitization is achieved through the up-regulation of proapoptotic factors such as <it>caspase </it>and <it>bcl </it>family gene expression. PTX and PTX + ADR also decrease E6 and E7 expression in SiHa cells, but not in HeLa cells. p53 was detected only in SiHa cells treated with ADR.</p> <p>Conclusion</p> <p>PTX is a good inducer of apoptosis but does not induce senescence. Furthermore, PTX reduced the ADR-induced senescence and increased apoptosis in cervix cancer cells.</p

Forest Biodiversity Assessment in Peruvian Andean Montane Cloud Forest

Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as rega rds biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the ?Bosque de Neblina de Cuyas?, in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity

Towards standards for human fecal sample processing in metagenomic studies

Technical variation in metagenomic analysis must be minimized to confidently assess the contributions of microbiota to human health. Here we tested 21 representative DNA extraction protocols on the same fecal samples and quantified differences in observed microbial community composition. We compared them with differences due to library preparation and sample storage, which we contrasted with observed biological variation within the same specimen or within an individual over time. We found that DNA extraction had the largest effect on the outcome of metagenomic analysis. To rank DNA extraction protocols, we considered resulting DNA quantity and quality, and we ascertained biases in estimates of community diversity and the ratio between Gram-positive and Gram-negative bacteria. We recommend a standardized DNA extraction method for human fecal samples, for which transferability across labs was established and which was further benchmarked using a mock community of known composition. Its adoption will improve comparability of human gut microbiome studies and facilitate meta-analyses