2,225 research outputs found

    Sustainable Strategy Based on Induced Precipitation for the Purification of Phycobiliproteins

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    Phycobiliproteins are fluorescent proteins mainly produced by red macroalgae and cyanobacteria. These proteins, essential to the survival of these organisms, find application in many fields of interest, from medical, pharmaceutical, and cosmetic to food and textile industries. The biggest obstacle to their use is the lack of simple environmental and economical sustainable methodologies to obtain these proteins with high purity. In this work, a new purification process is proposed based on the induced precipitation of the target proteins followed by ultrafiltration. Purities of 89.5% of both phycobiliproteins and 87.3% of R-phycoerythrin were achieved using ammonium sulfate and poly(acrylic acid) sodium salts as precipitation agents (followed by an ultrafiltration step), while maintaining high recovery yields and protein structure stability. Environmental analysis performed to evaluate the proposed process shows that the carbon footprint for the proposed process is much lower than that reported for alternative methodology, and the economic analysis reveals the cost-effective character associated to its high performance. This work is a step toward more sustainable and effective methodologies/processes with high industrial potential

    Quantum nondemolition measurement of mechanical motion quanta

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    The fields of opto- and electromechanics have facilitated numerous advances in the areas of precision measurement and sensing, ultimately driving the studies of mechanical systems into the quantum regime. To date, however, the quantization of the mechanical motion and the associated quantum jumps between phonon states remains elusive. For optomechanical systems, the coupling to the environment was shown to preclude the detection of the mechanical mode occupation, unless strong single photon optomechanical coupling is achieved. Here, we propose and analyse an electromechanical setup, which allows to overcome this limitation and resolve the energy levels of a mechanical oscillator. We find that the heating of the membrane, caused by the interaction with the environment and unwanted couplings, can be suppressed for carefully designed electromechanical systems. The results suggest that phonon number measurement is within reach for modern electromechanical setups.Comment: 8 pages, 5 figures plus 24 pages, 11 figures supplemental materia

    Social interaction, noise and antibiotic-mediated switches in the intestinal microbiota

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    The intestinal microbiota plays important roles in digestion and resistance against entero-pathogens. As with other ecosystems, its species composition is resilient against small disturbances but strong perturbations such as antibiotics can affect the consortium dramatically. Antibiotic cessation does not necessarily restore pre-treatment conditions and disturbed microbiota are often susceptible to pathogen invasion. Here we propose a mathematical model to explain how antibiotic-mediated switches in the microbiota composition can result from simple social interactions between antibiotic-tolerant and antibiotic-sensitive bacterial groups. We build a two-species (e.g. two functional-groups) model and identify regions of domination by antibiotic-sensitive or antibiotic-tolerant bacteria, as well as a region of multistability where domination by either group is possible. Using a new framework that we derived from statistical physics, we calculate the duration of each microbiota composition state. This is shown to depend on the balance between random fluctuations in the bacterial densities and the strength of microbial interactions. The singular value decomposition of recent metagenomic data confirms our assumption of grouping microbes as antibiotic-tolerant or antibiotic-sensitive in response to a single antibiotic. Our methodology can be extended to multiple bacterial groups and thus it provides an ecological formalism to help interpret the present surge in microbiome data.Comment: 20 pages, 5 figures accepted for publication in Plos Comp Bio. Supplementary video and information availabl

    Blockade of insulin-like growth factors increases efficacy of paclitaxel in metastatic breast cancer.

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    Breast cancer remains the leading cause of cancer death in women owing to metastasis and the development of resistance to established therapies. Macrophages are the most abundant immune cells in the breast tumor microenvironment and can both inhibit and support cancer progression. Thus, gaining a better understanding of how macrophages support cancer could lead to the development of more effective therapies. In this study, we find that breast cancer-associated macrophages express high levels of insulin-like growth factors 1 and 2 (IGFs) and are the main source of IGFs within both primary and metastatic tumors. In total, 75% of breast cancer patients show activation of insulin/IGF-1 receptor signaling and this correlates with increased macrophage infiltration and advanced tumor stage. In patients with invasive breast cancer, activation of Insulin/IGF-1 receptors increased to 87%. Blocking IGF in combination with paclitaxel, a chemotherapeutic agent commonly used to treat breast cancer, showed a significant reduction in tumor cell proliferation and lung metastasis in pre-clinical breast cancer models compared to paclitaxel monotherapy. Our findings provide the rationale for further developing the combination of paclitaxel with IGF blockers for the treatment of invasive breast cancer, and Insulin/IGF1R activation and IGF+ stroma cells as potential biomarker candidates for further evaluation

    Lung Adenocarcinoma of Never Smokers and Smokers Harbor Differential Regions of Genetic Alteration and Exhibit Different Levels of Genomic Instability

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    Recent evidence suggests that the observed clinical distinctions between lung tumors in smokers and never smokers (NS) extend beyond specific gene mutations, such as EGFR, EML4-ALK, and KRAS, some of which have been translated into targeted therapies. However, the molecular alterations identified thus far cannot explain all of the clinical and biological disparities observed in lung tumors of NS and smokers. To this end, we performed an unbiased genome-wide, comparative study to identify novel genomic aberrations that differ between smokers and NS

    Radiographers supporting radiologists in the interpretation of screening mammography: a viable strategy to meet the shortage in the number of radiologists.

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    BackgroundAn alternative approach to the traditional model of radiologists interpreting screening mammography is necessary due to the shortage of radiologists to interpret screening mammograms in many countries.MethodsWe evaluated the performance of 15 Mexican radiographers, also known as radiologic technologists, in the interpretation of screening mammography after a 6 months training period in a screening setting. Fifteen radiographers received 6 months standardized training with radiologists in the interpretation of screening mammography using the Breast Imaging Reporting and Data System (BI-RADS) system. A challenging test set of 110 cases developed by the Breast Cancer Surveillance Consortium was used to evaluate their performance. We estimated sensitivity, specificity, false positive rates, likelihood ratio of a positive test (LR+) and the area under the subject-specific Receiver Operating Characteristic (ROC) curve (AUC) for diagnostic accuracy. A mathematical model simulating the consequences in costs and performance of two hypothetical scenarios compared to the status quo in which a radiologist reads all screening mammograms was also performed.ResultsRadiographer's sensitivity was comparable to the sensitivity scores achieved by U.S. radiologists who took the test but their false-positive rate was higher. Median sensitivity was 73.3 % (Interquartile range, IQR: 46.7-86.7 %) and the median false positive rate was 49.5 % (IQR: 34.7-57.9 %). The median LR+ was 1.4 (IQR: 1.3-1.7 %) and the median AUC was 0.6 (IQR: 0.6-0.7). A scenario in which a radiographer reads all mammograms first, and a radiologist reads only those that were difficult for the radiographer, was more cost-effective than a scenario in which either the radiographer or radiologist reads all mammograms.ConclusionsGiven the comparable sensitivity achieved by Mexican radiographers and U.S. radiologists on a test set, screening mammography interpretation by radiographers appears to be a possible adjunct to radiologists in countries with shortages of radiologists. Further studies are required to assess the effectiveness of different training programs in order to obtain acceptable screening accuracy, as well as the best approaches for the use of non-physician readers to interpret screening mammography

    Cytokines and intrathecal IgG synthesis in multiple sclerosis patients during clinical remission

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    Cytokines and intrathecal IgG synthesis were determined in the cerebrospina fluid (CSF) and sera to evaluate inflammatory activity in multiple sclerosis (MS) patients during clinical remission. Although the disease was stable, there had been a significant increase of proinflammatory cytokines such as TNF alpha and IFN gamma in the CSF and serum, with no significant changes of IL12 and IL10 production. The changes in the cytokine production patterns were associated with an increase of leukocytes in the CSF, as well as the presence of oligoclonal bands suggesting intrathecal IgG synthesis. These results suggest that even when the disease is clinically silent, one can observe inflammatory activity in these MS patients.63491491

    Fanconi anemia manifesting as a squamous cell carcinoma of the hard palate: a case report

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    Fanconi Anemia is a rare autosomal recessive disorder characterized by various congenital malformations, progressive bone marrow failure at a very young age and of solid tumors development. The authors present a rare case of a squamous cell carcinoma of the hard palate in a Fanconi Anaemia patient. The atypical clinical manifestation rendered the diagnosis more difficult. This case, for age of appearance, sex and localization, is unique in international literature. We recommend a quarterly follow up of the oral-rhino-pharynx complex in FA patients and to consider as carcinomas, all oral lesions that last more than two weeks

    Chromosome copy number changes carry prognostic information independent of KIT/PDGFRA point mutations in gastrointestinal stromal tumors

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    <p>Abstract</p> <p>Background</p> <p>Oncogenic point mutations in <it>KIT </it>or <it>PDGFRA </it>are recognized as the primary events responsible for the pathogenesis of most gastrointestinal stromal tumors (GIST), but additional genomic alterations are frequent and presumably required for tumor progression. The relative contribution of such alterations for the biology and clinical behavior of GIST, however, remains elusive.</p> <p>Methods</p> <p>In the present study, somatic mutations in <it>KIT </it>and <it>PDGFRA </it>were evaluated by direct sequencing analysis in a consecutive series of 80 GIST patients. For a subset of 29 tumors, comparative genomic hybridization was additionally used to screen for chromosome copy number aberrations. Genotype and genomic findings were cross-tabulated and compared with available clinical and follow-up data.</p> <p>Results</p> <p>We report an overall mutation frequency of 87.5%, with 76.25% of the tumors showing alterations in <it>KIT </it>and 11.25% in <it>PDGFRA</it>. Secondary <it>KIT </it>mutations were additionally found in two of four samples obtained after imatinib treatment. Chromosomal imbalances were detected in 25 out of 29 tumors (86%), namely losses at 14q (88% of abnormal cases), 22q (44%), 1p (44%), and 15q (36%), and gains at 1q (16%) and 12q (20%). In addition to clinico-pathological high-risk groups, patients with <it>KIT </it>mutations, genomic complexity, genomic gains and deletions at either 1p or 22q showed a significantly shorter disease-free survival. Furthermore, genomic complexity was the best predictor of disease progression in multivariate analysis.</p> <p>Conclusions</p> <p>In addition to <it>KIT/PDGFRA </it>mutational status, our findings indicate that secondary chromosomal changes contribute significantly to tumor development and progression of GIST and that genomic complexity carries independent prognostic value that complements clinico-pathological and genotype information.</p
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