2,142 research outputs found

    Floral nectar: fifty years of new ecological perspectives beyond pollinator reward

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    Floral nectar is central to ecology, since it mediates interactions with pollinators, flower-visiting antagonists and microbes through its chemical composition. Here we review how historical assumptions about its ecological meaning were first challenged, then modified and expanded since the discovery of secondary metabolites in nectar. We then explore the origin of specific neuroactive nectar compounds known to act as important insect neurotransmitters, and how advances in the field of bee cognition and plant-microbe-animal interactions challenge such historical views. As all actors involved in the latter interactions are under simultaneous reciprocal selective pressures, their coexistence is characterized by conflicts and trade-offs, the evolutionary interpretation of which suggests exciting new perspectives in one of the longest studied aspects of plant-pollinator interactions

    Secondary Metabolites in Nectar-Mediated Plant-Pollinator Relationships

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    n recent years, our understanding of the complex chemistry of floral nectar and its ecological implications for plant-pollinator relationships has certainly increased. Nectar is no longer considered merely a reward for pollinators but rather a plant interface for complex interactions with insects and other organisms. A particular class of compounds, i.e., nectar secondary compounds (NSCs), has contributed to this new perspective, framing nectar in a more comprehensive ecological context. The aim of this review is to draft an overview of our current knowledge of NSCs, including emerging aspects such as non-protein amino acids and biogenic amines, whose presence in nectar was highlighted quite recently. After considering the implications of the different classes of NSCs in the pollination scenario, we discuss hypotheses regarding the evolution of such complex nectar profiles and provide cues for future research on plant-pollinator relationships

    Configuration of User/Node affinity in a Sendmail+Dovecot+Squirrelmail e-mail cluster

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    The storage of user e-mail boxes on a shared filesystem and their read/write access on multiple cluster nodes requires special care to benefit from file persistence in the filesystem cache on each node and to prevent system response to be significantly degraded by frequent file synchronisations onto physical storage. The simplest measure towards this goal is to divide access to nodes on a per-user basis, while keeping the cluster failsafe. In this paper we share a few non-obvious details for the configuration of such user/node affinity in sendmail, dovecot, squirrelmail

    Ki-67 Labeling Index in Primary Invasive Breast Cancer from Sudanese Patients: A Pilot Study

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    Ki-67 labeling index has been linked to patient outcome in breast cancer patients. However, very few published reports have examined Ki-67 labeling index in African breast cancer patients. Sixty-two Sudanese breast cancer patients with primary invasive tumors were immunostained for Ki-67, ER, PR, Her-2/neu, CK5/6, and CK17. Ki-67 labeling index ranged from 0% to 50%, with a median of 5% (interquartile range 0–10). Low Ki-67 labeling index (immunostaining < 10%) was detected in 43/62 (69.4%) with a median of 0 (interquartile range 0–5), whereas high Ki-67 labeling index (immunostaining ≥ 10%) was revealed in 19/62 (30.6%) with a median of 20 (interquartile range 12–26). Ki-67 labeling index was significantly associated with tumor grade (P=0.022, Mann-Whitney U Test). There were no significant group differences between Ki-67 labeling index and ER (P=0.43), PR (P=0.7), Her-2/neu (P=0.45), CK5/6 (P=0.29), CK17 (P=0.55), pathologic stage (P=0.4), tumor histology (P=0.99), breast cancer subtypes (P=0.47), tumor size (P=0.16), and age at diagnosis (P=0.6). These results suggested that Ki-67 labeling index correlates with tumor differentiation and not with the tumor size or any other tested marker in Sudanese breast cancers. Thus, Ki-67 labeling index could be considered as a reliable measure of tumor proliferative fraction in Sudan

    Ki-67 Labeling Index in Primary Invasive Breast Cancer from Sudanese Patients: A Pilot Study

    Get PDF
    Ki-67 labeling index has been linked to patient outcome in breast cancer patients. However, very few published reports have examined Ki-67 labeling index in African breast cancer patients. Sixty-two Sudanese breast cancer patients with primary invasive tumors were immunostained for Ki-67, ER, PR, Her-2/neu, CK5/6, and CK17. Ki-67 labeling index ranged from 0% to 50%, with a median of 5% (interquartile range 0–10). Low Ki-67 labeling index (immunostaining < 10%) was detected in 43/62 (69.4%) with a median of 0 (interquartile range 0–5), whereas high Ki-67 labeling index (immunostaining ≥ 10%) was revealed in 19/62 (30.6%) with a median of 20 (interquartile range 12–26). Ki-67 labeling index was significantly associated with tumor grade (P=0.022, Mann-Whitney U Test). There were no significant group differences between Ki-67 labeling index and ER (P=0.43), PR (P=0.7), Her-2/neu (P=0.45), CK5/6 (P=0.29), CK17 (P=0.55), pathologic stage (P=0.4), tumor histology (P=0.99), breast cancer subtypes (P=0.47), tumor size (P=0.16), and age at diagnosis (P=0.6). These results suggested that Ki-67 labeling index correlates with tumor differentiation and not with the tumor size or any other tested marker in Sudanese breast cancers. Thus, Ki-67 labeling index could be considered as a reliable measure of tumor proliferative fraction in Sudan

    Contaminant effect on cellular metabolic differential pressure curves.

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    The possibility of a pressure monitoring system by differential pressure sensors to detect contaminant effects on cellular cultures metabolic activity is discussed using Saccharomyces cerevisiae, lymphocyte, and AHH1 cell cultures. Metabolic (aerobic and anaerobic) processes in cells are accompanied by CO2 production that induces changes in pressure values when cells are cultured in sealed vessels. These values are subsequently converted in voltage units and plotted pressure dynamics versus time. This procedure leads to a standard curve, typical of the cellular line, which characterizes cellular metabolism when all parameters are controlled, such as temperature and nutrients. Different phases appear in the S. cerevisiae differential pressure curve: an initial growth up to a maximum, followed by a decrement that leads to a typical "depression" (pressure values inside the test-tubes are lower than the initial one) after about 35 h from the beginning. The S. cerevisiae differential pressure curve is successfully used to test the effects of chemical (Amuchina(R), trieline) and physical (UV radiation, blue light, magnetic fields) contaminants. The same technique is applied to lymphocytes and AHH1 cultures to investigate the effects generated by a 72-h exposure to a 50-Hz, 60-muT electromagnetic field. Lymphocyte samples, cultured in a PHA medium, grow less than control ones, but exhibit a greater metabolic activity: changes in the exposure system configuration influence neither sample growth differences nor metabolic response variations between control and irradiated samples, while all the other irradiation parameters remain constant. Control and irradiated lymphocyte samples, without PHA in culture medium, show the same behavior both during irradiation and metabolic test. AHH1 control and irradiated samples show no difference both in growth percentage during irradiation and in metabolic activity. Different cell cultures respond to the same stimulus in different manners. (C) 2004 Society of Photo-Optical Instrumentation Engineers

    Thermodynamic analysis for SOFC/ICE integration in hybrid systems for maritime application

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    As the International Maritime Organization has set 2030 and 2050 targets to reduce the environmental impact of the maritime sector, it is mandatory to investigate innovative solutions aimed at fuel saving and reduction of ship emissions. In this paper, the integration of Solid Oxide Fuel Cells (SOFC) and Internal Combustion Engine (ICE) is investigated for maritime application, targeting a short-sea ferry as a case study operated by a marine gas engine (MGE) rated 750 kW. The paper aims to model via an in-house tool (WTEMP) the proposed hybrid system and study thermodynamic interaction among the two main energy systems, SOFC and ICE, considering blending anode-off gas from the SOFC with natural gas in the ICE. The results showed relevant efficiency enhancement and fuel/CO2 emission savings if compared with traditional MGE while the main source of exergy loss of the hybrid system is ICE

    predictive biomarkers of response for pd 1 pd l1 inhibitors a cumbersome gold rush

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    Programmed cell death protein 1 (PD-1) and its ligand programmed cell death-ligand 1 (PD-L1) are overexpressed in a number of human malignancies. More interestingly, their expression has been associated with patient survival in non-small cell lung cancer (NSCLC), melanoma, renal cell carcinoma, esophageal, pancreatic and colorectal carcinoma, with the data commonly suggesting a negative prognostic role. In this review, we summarize the pros and cons regarding the predictive role of PD-L1 expression in candidate patients for checkpoint inhibitors. Furthermore, we discuss the potential predictive role of other biomarkers, such as tumor mutational burden, microsatellite instability, mismatch repair deficiency and tumor infiltrating lymphocytes. We conclude that PD-L1 testing probably represents simply a "snapshot" of an intricate, fluctuating and dynamic process, that in turn represents the interplay between the immune system and cancer. The PD-L1 assay can be considered more useful for response stratification than in patient selection

    Atypical primary pulmonary meningioma: A report of a case suspected of being a lung metastasis

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    Primary extracranial and extraspinal meningiomas are very rare tumours, and primary pulmonary ones are even more uncommon. They present as a solitary pulmonary nodule, and most of them are benign, except for three cases. We describe a primitive atypical pulmonary meningioma first suspected of being a metastasis in a patient during follow-up ten years after therapy for breast cancer. © the authors; licensee ecancermedicalscience
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