101 research outputs found
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
Testing in Mice the Hypothesis That Melanin Is Protective in Malaria Infections
Malaria has had the largest impact of any infectious disease on shaping the human genome, exerting enormous selective pressure on genes that improve survival in severe malaria infections. Modern humans originated in Africa and lost skin melanization as they migrated to temperate regions of the globe. Although it is well documented that loss of melanization improved cutaneous Vitamin D synthesis, melanin plays an evolutionary ancient role in insect immunity to malaria and in some instances melanin has been implicated to play an immunoregulatory role in vertebrates. Thus, we tested the hypothesis that melanization may be protective in malaria infections using mouse models. Congenic C57BL/6 mice that differed only in the gene encoding tyrosinase, a key enzyme in the synthesis of melanin, showed no difference in the clinical course of infection by Plasmodium yoelii 17XL, that causes severe anemia, Plasmodium berghei ANKA, that causes severe cerebral malaria or Plasmodium chabaudi AS that causes uncomplicated chronic disease. Moreover, neither genetic deficiencies in vitamin D synthesis nor vitamin D supplementation had an effect on survival in cerebral malaria. Taken together, these results indicate that neither melanin nor vitamin D production improve survival in severe malaria
Memantine increases NMDA receptor level in the prefrontal cortex but fails to reverse apomorphine-induced conditioned place preference in rats
Studies have shown that inflammation and neurodegeneration may accompany the development of addiction to apomorphine and that the glutamate NMDA receptor antagonist, memantine, may be neuroprotective. The similarity between apomorphine and dopamine with regard to their chemical, pharmacological and toxicological properties provided a basis for investigating the mechanism of action of the former agent. In this study, we investigated whether memantine would suppress apomorphine-seeking behavior in rats subjected to apomorphine-induced place preference conditioning, through modulation of NMDA receptors in the prefrontal cortex. Repeated apomorphine (1 mg/kg) treatment induced conditioned place preference (CPP) and had no significant effect on NMDA receptor levels in the prefrontal cortex. Prior treatment with memantine (5 mg/kg or 10 mg/kg) increased the levels of NMDA receptors in the prefrontal cortex but did not suppress CPP induced by apomorphine. These data give further support to the addictive effect of apomorphine and demonstrate that blockade of NMDA receptors by memantine is unable to suppress apomorphine-seeking behavior
Profile of Central and Effector Memory T Cells in the Progression of Chronic Human Chagas Disease
Chagas disease is a parasitic infection caused by protozoan Trypanosoma cruzi that affects approximately 11 million people in Latin America. The involvement of the host's immune response on the development of severe forms of Chagas disease has not been fully elucidated. Studies on the immune response against T. cruzi infection show that the immunoregulatory mechanisms are necessary to prevent the deleterious effect of excessive immune response stimulation and consequently the fatal outcome of the disease. A recall response against parasite antigens observed in in vitro peripheral blood cell culture clearly demonstrates that memory response is generated during infection. Memory T cells are heterogeneous and differ in both the ability to migrate and exert their effector function. This heterogeneity is reflected in the definition of central (TCM) and effector memory (TEM) T cells. Our results suggest that a balance between regulatory and effectors T cells may be important for the progression and development of the disease. Furthermore, the high percentage of central memory CD4+ T cells in indeterminate patients after stimulation suggests that these cells may modulate host's inflammatory response by controlling cell migration to tissues and their effector role during chronic phase of the disease
Disease-free survival in patients with non-metastatic breast cancer
SUMMARY Introduction: Breast cancer is the second most common malignancy in the world and the one with highest incidence in the female population; it is also a major cause of death from cancer among women. Objective: To analyze the disease-free survival (DFS) at 5 years and prognostic factors in women with non-metastatic invasive breast cancer treated at a referral center for cancer care located in a medium-sized city in the Southeast of Brazil. Method: Patients diagnosed with the disease between 2003 and 2005 and identified through the institution’s cancer hospital records were analyzed. The follow-up of cases was carried out through hospital records, and complemented by search in the database of the Mortality Information System (SIM) as well as telephone contact. The variables analyzed were distributed in the following blocks: socio-demographic data, tumor-related characteristics, and treatment-related characteristics. Survival functions were calculated using the Kaplan-Meier method and the prognostic factors were analyzed based on Cox proportional hazard model. Results: The study showed a DFS at 5 years of 72% (95CI 67.6-75.9). The main variables independently associated with DFS were lymph node involvement, use of hormone therapy, and education level. Conclusion: This study reinforces the importance of early diagnosis for DFS, pointing to the role of social aspects in this regard. The relevance of this research in the country is also highlighted, given the scarcity of studies on DFS in the Brazilian population
Pan-cancer analysis of whole genomes
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe
Bio-composting oil palm waste for improvement of soil fertility
Sources of bio-compost as agro-industrial wastes includes wide range of oil palm wastes viz. waste, biomass, palm kernels, empty fruit bunch, mill effluent, trunk and frond compost. Various composting processes are summarized in brief with distinct reference of oil–palm composting covering aerated static pile, and co-composting with earthworms (vermicomposting). However, in-vessel composting and windrow composting has meritorious advantages in composting. This review article refers to various significant roles played by microorganisms associated. Noteworthy study of bio-compost applications and procedures are correspondingly glosses framework of ecological, economical and agro-ecosystemic benefits
Coping in aged people with Alzheimer's disease Coping en ancianos con la enfermedad de Alzheimer Coping em idosos com doença de Alzheimer
The intensity of stress experiences and elaboration of coping essentially depend on individuals' cognitive assessment. Considering the cognitive impairment of elderly persons with Alzheimer's disease (DA), this study aimed to identify their coping style. The Jalowiec Coping Inventory was applied to 60 elderly, 30 in the control group and 30 in the DA group. The results demonstrated a predominance of emotion-focused coping in the DA group and problem-focused coping in the control group, but the difference was not statistically significant (p=0.124). In addition, it was observed that individuals with better cognitive development in the DA group selected problem-focused coping strategies (p=0.0074). Thus, it seems there is a tendency to select evasive and emotional control strategies in demented elderly with worsened cognitive performance, rather than attempting to solve the problem or minimize its consequences.<br>La elaboración de estrategias de ataque a las situaciones estresantes depende de la evaluación cognitiva hecha por el individuo. Considerando el déficit cognitivo de los ancianos con la enfermedad de Alzheimer (DA), este estudio tuvo por objetivo verificar el estilo de coping predominantemente utilizado por ellos. Para esto, fue aplicado el inventario de Coping de Jalowiec en 60 ancianos, de los cuales 30 individuos eran cognitivamente saludables (grupo control) y 30 individuos con DA. Se observó un predominio del coping enfocado en la emoción en el grupo DA y enfocado en el problema en el grupo control, aunque no hubo una diferencia significativa. Así, parece haber una tendencia, en los ancianos con demencia, a elegir estrategias evasivas y de control emocional, en detrimento de la tentativa de solucionar el problema o minimizar sus consecuencias.<br>A intensidade da experiência do estresse e a elaboração do coping dependem, fundamentalmente, da avaliação cognitiva feita pelo indivíduo. Considerando o déficit cognitivo de idosos com doença de Alzheimer (DA), este estudo teve por objetivo identificar o estilo de coping utilizado por eles. Para isso, foi aplicado o Inventário de Coping de Jalowiec em 60 idosos, sendo 30 do grupo controle e 30 com DA. Os resultados evidenciaram o predomínio do coping focado na emoção no grupo DA e focado no problema no grupo controle, porém, não houve diferença significativa (p=0,124). Além disso, observou-se que, quanto melhor o desempenho cognitivo dos idosos com DA, maior a tendência em utilizar estratégias de coping focadas no problema (p=0,0074). Assim, parece haver tendência à seleção de estratégias evasivas e de controle emocional nos idosos dementes com pior desempenho cognitivo, em detrimento da tentativa de solucionar o problema ou minimizar suas conseqüências
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