Scaling limit for a drainage network model

We consider the two dimensional version of a drainage network model introduced by Gangopadhyay, Roy and Sarkar, and show that the appropriately rescaled family of its paths converges in distribution to the Brownian web. We do so by verifying the convergence criteria proposed by Fontes, Isopi, Newman and Ravishankar.Comment: 15 page

Targeting RAGE prevents muscle wasting and prolongs survival in cancer cachexia

Background: Cachexia, a multifactorial syndrome affecting more than 50% of patients with advanced cancer and responsible for ~20% of cancer-associated deaths, is still a poorly understood process without a standard cure available. Skeletal muscle atrophy caused by systemic inflammation is a major clinical feature of cachexia, leading to weight loss, dampening patients' quality of life, and reducing patients' response to anticancer therapy. RAGE (receptor for advanced glycation end-products) is a multiligand receptor of the immunoglobulin superfamily and a mediator of muscle regeneration, inflammation, and cancer. Methods: By using murine models consisting in the injection of colon 26 murine adenocarcinoma (C26-ADK) or Lewis lung carcinoma (LLC) cells in BALB/c and C57BL/6 or Ager−/− (RAGE-null) mice, respectively, we investigated the involvement of RAGE signalling in the main features of cancer cachexia, including the inflammatory state. In vitro experiments were performed using myotubes derived from C2C12 myoblasts or primary myoblasts isolated from C57BL/6 wild type and Ager−/− mice treated with the RAGE ligand, S100B (S100 calcium-binding protein B), TNF (tumor necrosis factor)α±IFN (interferon) γ, and tumour cell- or masses-conditioned media to analyse hallmarks of muscle atrophy. Finally, muscles of wild type and Ager−/− mice were injected with TNFα/IFNγ or S100B in a tumour-free environment. Results: We demonstrate that RAGE is determinant to activate signalling pathways leading to muscle protein degradation in the presence of proinflammatory cytokines and/or tumour-derived cachexia-inducing factors. We identify the RAGE ligand, S100B, as a novel factor able to induce muscle atrophy per se via a p38 MAPK (p38 mitogen-activated protein kinase)/myogenin axis and STAT3 (signal transducer and activator of transcription 3)-dependent MyoD (myoblast determination protein 1) degradation. Lastly, we found that in cancer conditions, an increase in serum levels of tumour-derived S100B and HMGB1 (high mobility group box 1) occurs leading to chronic activation/overexpression of RAGE, which induces hallmarks of cancer cachexia (i.e. muscle wasting, systemic inflammation, and release of tumour-derived pro-cachectic factors). Absence of RAGE in mice translates into reduced serum levels of cachexia-inducing factors, delayed loss of muscle mass and strength, reduced tumour progression, and increased survival. Conclusions: RAGE is a molecular determinant in inducing the hallmarks of cancer cachexia, and molecular targeting of RAGE might represent a therapeutic strategy to prevent or counteract the cachectic syndrome

Yang-Mills Action from Open Superstring Field Theory

We calculate the effective action for nonabelian gauge bosons up to quartic order using WZW-like open superstring field theory. After including level zero and level one contributions, we obtain with 75% accuracy the Yang-Mills quartic term. We then prove that the complete effective action reproduces the exact Yang-Mills quartic term by analytically performing a summation over the intermediate massive states.Comment: 10 page

Análise sensorial da aparência de cinco tipos de palmitos: com e sem rotulagem.

O palmito é considerado uma iguaria tipicamente brasileira e de grande aceitação no mercado, tanto interno quanto externo, sendo que, nos EUA e na Europa, esse compete com produtos como alcachofra e aspargo. É classificado como uma hortaliça não convencional e pode ser extraído de várias espé cies de palmeiras, sendo que a escolha destas depende de fatores como disponibilidade, palatabilidade, cor, formato e rendimento, além da facilidade de extração. No Brasil, antes da década de 60, a extração era feita de forma predatória e concentrava-se no palmito do tipo Juçara, nativo da Mata Atlântica. Como este apresenta um ciclo longo e sua palmeira não perfilha (necessita de replantio) sua presença natural foi quase exterminada. Devido ao aumento da fiscalização por órgãos oficiais impedindo a devastação predatória, ao custo do reflorestamento e ao alto preço do produto no mercado externo, houve um incentivo ao plantio comercial e produção racional de palmito industrializado. Para isso, houve uma busca por gêneros da família Palmae que fornecessem palmito de boa qualidade em curto prazo. As espécies de maior importância sócio-econômica e ambiental são: Juçara, Açaí, Pupunha, Palmeira Real e Babaçu. Portanto, o objetivo desse trabalho foi avaliar a preferência dos palmitos quanto a aparência do produto em salmoura sem e com a rotulagem. Inicialmente foi aplicado um questionário para caracterizar o perfil do consumidor e em seguida foi realizado os testes de ordenação da preferência (1= desgostei e 5= gostei) quanto à aparência dos palmitos. Para ambos os testes foram utilizados 50 provadores, que ordenaram as amostras da esquerda para a direita conforme a cor e preferência. A interpretação dos dados obtidos nos testes de ordenação de preferência visual foi de acordo com a ABNT (1994). Para os resultados (5 amostras e 50 respostas) constatou-se que, para que haja diferença significativa entre as amostras ao nível de 5% de significância, a diferença entre o somatório de cada par de amostras deve ser igual ou maior que 44. Com o resultado da caracterização do grupo dos provadores, foi possível notar que a forma de consumo ficou em sua maioria no consumo do tipo salada e em recheio de salgados. Já os itens observados que decidiriam a compra de um determinado palmito foram: data de validade, preço e o tipo de palmito seriam os mais importantes. Quanto à preferência dos palmitos sem rotulo, os resultados mostraram a seguinte ordem nos valores dos somatórios: Babaçu (119) < Pupunha (132) < Juçara (154) < Palmeira Real (170) < Açaí (175). Verificou-se, portanto, que houve diferença significativa (p?0,05) entre o Babaçu e os palmitos Palmeira Real e Açaí, porém o não ocorreu diferença na preferência entre as demais. Quanto a preferência dos palmitos com rotulagem em relação a embalagem, verificou-se que as somatórias foram: Babaçu (117) < Palmeira Real (150) < Juçara (153) < Açaí (162) < Pupunha (168) com diferença significativa (p?0,05) entre o Babaçu e os palmitos Açaí e Pupunha. Desta maneira conclui-se que a rotulagem afetou significativamente a escolha do produto, com exceção do Babaçu que obteve resultados inferiores nos dois testes

Effect of Chemical Vapor Deposition WS2 on Viability and Differentiation of SH-SY5Y Cells

In recent years, transition metal dichalcogenides have been attracting an increasing interest in the biomedical field, thus implying the need of a deeper understanding of their impact on cell behavior. In this study we investigate tungsten disulfide (WS2) grown via chemical vapor deposition (CVD) on a transparent substrate (sapphire) as a platform for neural-like cell culture. We culture SH-SY5Y human neuroblastoma cells on WS2, using graphene, sapphire and standard culture well as controls. The quality, thickness and homogeneity of the materials is analyzed using atomic force microscopy and Raman spectroscopy. The cytocompatibility of CVD WS2 is investigated for the first time by cell viability and differentiation assessment on SH-SY5Y cells. We find that cells differentiated on WS2, displaying a viability and neurite length comparable with the controls. These findings shine light on the possibility of using WS2 as a cytocompatible material for interfacing neural cells

Rbm24 displays dynamic functions required for myogenic differentiation during muscle regeneration

Skeletal muscle has a remarkable capacity of regeneration after injury, but the regulatory network underlying this repair process remains elusive. RNA-binding proteins play key roles in the post-transcriptional regulation of gene expression and the maintenance of tissue homeostasis and plasticity. Rbm24 regulates myogenic differentiation during early development, but its implication in adult muscle is poorly understood. Here we show that it exerts multiple functions in muscle regeneration. Consistent with its dynamic subcellular localization during embryonic muscle development, Rbm24 also displays cytoplasm to nucleus translocation during C2C12 myoblast differentiation. In adult mice, Rbm24 mRNA is enriched in slow-twitch muscles along with myogenin mRNA. The protein displays nuclear localization in both slow and fast myofibers. Upon injury, Rbm24 is rapidly upregulated in regenerating myofibers and accumulates in the myonucleus of nascent myofibers. Through satellite cell transplantation, we demonstrate that Rbm24 functions sequentially to regulate myogenic differentiation and muscle regeneration. It is required for myogenin expression at early stages of muscle injury and for muscle-specific pre-mRNA alternative splicing at late stages of regeneration. These results identify Rbm24 as a multifaceted regulator of myoblast differentiation. They provide insights into the molecular pathway orchestrating the expression of myogenic factors and muscle functional proteins during regeneration