120 research outputs found
A citation-based map of concepts in invasion biology
Invasion biology has been quickly expanding in the last decades so that it is now metaphorically flooded with publications, concepts, and hypotheses. Among experts, there is no clear consensus about the relationships between invasion concepts, and almost no one seems to have a good overview of the literature anymore. Similar observations can be made for other research fields. Science needs new navigation tools so that researchers within and outside of a research field as well as science journalists, students, teachers, practitioners, policy-makers, and others interested in the field can more easily understand its key ideas. Such navigation tools could, for example, be maps of the major concepts and hypotheses of a research field. Applying a bibliometric method, we created such maps for invasion biology. We analysed research papers of the last two decades citing at least two of 35 common invasion hypotheses. Co-citation analysis yields four distinct clusters of hypotheses. These clusters can describe the main directions in invasion biology and explain basic driving forces behind biological invasions. The method we outline here for invasion biology can be easily applied for other research fields
Progress in higher education reform across Europe, Governance reform, Volume 3: Governance fiches
A conceptual map of invasion biology: Integrating hypotheses into a consensus network
Background and aims
Since its emergence in the mid‐20th century, invasion biology has matured into a productive research field addressing questions of fundamental and applied importance. Not only has the number of empirical studies increased through time, but also has the number of competing, overlapping and, in some cases, contradictory hypotheses about biological invasions. To make these contradictions and redundancies explicit, and to gain insight into the field’s current theoretical structure, we developed and applied a Delphi approach to create a consensus network of 39 existing invasion hypotheses.
Results
The resulting network was analysed with a link‐clustering algorithm that revealed five concept clusters (resource availability, biotic interaction, propagule, trait and Darwin’s clusters) representing complementary areas in the theory of invasion biology. The network also displays hypotheses that link two or more clusters, called connecting hypotheses, which are important in determining network structure. The network indicates hypotheses that are logically linked either positively (77 connections of support) or negatively (that is, they contradict each other; 6 connections).
Significance
The network visually synthesizes how invasion biology’s predominant hypotheses are conceptually related to each other, and thus, reveals an emergent structure – a conceptual map – that can serve as a navigation tool for scholars, practitioners and students, both inside and outside of the field of invasion biology, and guide the development of a more coherent foundation of theory. Additionally, the outlined approach can be more widely applied to create a conceptual map for the larger fields of ecology and biogeography
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Targeting the vasopressin type-2 receptor for renal cell carcinoma therapy.
Arginine vasopressin (AVP) and its type-2 receptor (V2R) play an essential role in the regulation of salt and water homeostasis by the kidneys. V2R activation also stimulates proliferation of renal cell carcinoma (RCC) cell lines in vitro. The current studies investigated V2R expression and activity in human RCC tumors, and its role in RCC tumor growth. Examination of the cancer genome atlas (TCGA) database, and analysis of human RCC tumor tissue microarrays, cDNA arrays and tumor biopsy samples demonstrated V2R expression and activity in clear cell RCC (ccRCC). In vitro, V2R antagonists OPC31260 and Tolvaptan, or V2R gene silencing reduced wound closure and cell viability of 786-O and Caki-1 human ccRCC cell lines. Similarly in mouse xenograft models, Tolvaptan and OPC31260 decreased RCC tumor growth by reducing cell proliferation and angiogenesis, while increasing apoptosis. In contrast, the V2R agonist dDAVP significantly increased tumor growth. High intracellular cAMP levels and ERK1/2 activation were observed in human ccRCC tumors. In mouse tumors and Caki-1 cells, V2R agonists reduced cAMP and ERK1/2 activation, while dDAVP treatment had the reverse effect. V2R gene silencing in Caki-1 cells also reduced cAMP and ERK1/2 activation. These results provide novel evidence for a pathogenic role of V2R signaling in ccRCC, and suggest that inhibitors of the AVP-V2R pathway, including the FDA-approved drug Tolvaptan, could be utilized as novel ccRCC therapeutics
Abnormal intraepidermal nerve fiber density in disease: A scoping review
BackgroundIntraepidermal nerve fiber density (IENFD) has become an important biomarker for neuropathy diagnosis and research. The consequences of reduced IENFD can include sensory dysfunction, pain, and a significant decrease in quality of life. We examined the extent to which IENFD is being used as a tool in human and mouse models and compared the degree of fiber loss between diseases to gain a broader understanding of the existing data collected using this common technique.MethodsWe conducted a scoping review of publications that used IENFD as a biomarker in human and non-human research. PubMed was used to identify 1,004 initial articles that were then screened to select articles that met the criteria for inclusion. Criteria were chosen to standardize publications so they could be compared rigorously and included having a control group, measuring IENFD in a distal limb, and using protein gene product 9.5 (PGP9.5).ResultsWe analyzed 397 articles and collected information related to publication year, the condition studied, and the percent IENFD loss. The analysis revealed that the use of IENFD as a tool has been increasing in both human and non-human research. We found that IENFD loss is prevalent in many diseases, and metabolic or diabetes-related diseases were the most studied conditions in humans and rodents. Our analysis identified 73 human diseases in which IENFD was affected, with 71 reporting IENFD loss and an overall average IENFD change of −47%. We identified 28 mouse and 21 rat conditions, with average IENFD changes of −31.6% and −34.7%, respectively. Additionally, we present data describing sub-analyses of IENFD loss according to disease characteristics in diabetes and chemotherapy treatments in humans and rodents.InterpretationReduced IENFD occurs in a surprising number of human disease conditions. Abnormal IENFD contributes to important complications, including poor cutaneous vascularization, sensory dysfunction, and pain. Our analysis informs future rodent studies so they may better mirror human diseases impacted by reduced IENFD, highlights the breadth of diseases impacted by IENFD loss, and urges exploration of common mechanisms that lead to substantial IENFD loss as a complication in disease
The Adaptability of Full Cast Crown in Preclinical Practice
A study was made to evaluate the adaptability of full cast crowns in preclinical practice of the fifth year students at Matsumoto Dental College in 1984. Gap space between the inner surface of the full cast crown and the surface of the abutment tooth was investigated with silicon material. The results were as follows: 1) The adaptability of crowns was better at the mesial surface than at the distal surface, and better at the lingual surface than at the buccal surface. 2) The adaptability of crowns was better at the axial walls, especialy in the middle, than in the cervical margin. 3) At the occulusal surface, the adaptability of crowns was worst
Carboxyl-terminal truncated HBx regulates a distinct microRNA transcription program in Hepatocellular carcinoma development
Background: The biological pathways and functional properties by which misexpressed microRNAs (miRNAs) contribute to liver carcinogenesis have been intensively investigated. However, little is known about the upstream mechanisms that deregulate miRNA expressions in this process. In hepatocellular carcinoma (HCC), hepatitis B virus (HBV) X protein (HBx), a transcriptional trans-activator, is frequently expressed in truncated form without carboxyl-terminus but its role in miRNA expression and HCC development is unclear. Methods: Human non-tumorigenic hepatocytes were infected with lentivirus-expressing full-length and carboxyl-terminal truncated HBx (Ct-HBx) for cell growth assay and miRNA profiling. Chromatin immunoprecipitation microarray was performed to identify the miRNA promoters directly associated with HBx. Direct transcriptional control was verified by luciferase reporter assay. The differential miRNA expressions were further validated in a cohort of HBV-associated HCC tissues using real-time PCR. Results: Hepatocytes expressing Ct-HBx grew significantly faster than the full-length HBx counterparts. Ct-HBx decreased while full-length HBx increased the expression of a set of miRNAs with growth-suppressive functions. Interestingly, Ct-HBx bound to and inhibited the transcriptional activity of some of these miRNA promoters. Notably, some of the examined repressed-miRNAs (miR-26a, -29c, -146a and -190) were also significantly down-regulated in a subset of HCC tissues with carboxyl-terminal HBx truncation compared to their matching non-tumor tissues, highlighting the clinical relevance of our data. Conclusion: Our results suggest that Ct-HBx directly regulates miRNA transcription and in turn promotes hepatocellular proliferation, thus revealing a viral contribution of miRNA deregulation during hepatocarcinogenesis. © 2011 Yip et al.published_or_final_versio
The hierarchy-of-hypotheses approach: A synthesis method for enhancing theory development in ecology and evolution
13 páginas.- 4 figuras.- referencias.- Supplemental material is available at BIOSCI online. https://doi.org/10.1093/biosci/biaa130In the current era of Big Data, existing synthesis tools such as formal meta-analyses are critical means to handle the deluge of information. However, there is a need for complementary tools that help to (a) organize evidence, (b) organize theory, and (c) closely connect evidence to theory. We present the hierarchy-of-hypotheses (HoH) approach to address these issues. In an HoH, hypotheses are conceptually and visually structured in a hierarchically nested way where the lower branches can be directly connected to empirical results. Used for organizing evidence, this tool allows researchers to conceptually connect empirical results derived through diverse approaches and to reveal under which circumstances hypotheses are applicable. Used for organizing theory, it allows researchers to uncover mechanistic components of hypotheses and previously neglected conceptual connections. In the present article, we offer guidance on how to build an HoH, provide examples from population and evolutionary biology and propose terminological clarifications.The workshops were funded by Volkswagen Foundation (Az 92,807 and 94,246). TH, CAA, ME, PG, ADS, and JMJ received funding from German Federal Ministry of Education and Research within the Collaborative Project “Bridging in Biodiversity Science” (grant no. 01LC1501A). ME additionally received funding from the Foundation of German Business, JMJ from the Deutsche Forschungsgemeinschaft (grants no. JE 288/9–1 and JE 288/9–2), and IB from German Federal Ministry of Education and Research (grant no. FKZ 01GP1710). CJL was supported by a grant from The Natural Sciences and Engineering Research Council of Canada and in-kind synthesis support from the US National Center for Ecological Analysis and Synthesis. LGA was supported by the Spanish Ministry of Science, Innovation, and Universities through project no. CGL2014–56,739-R, and RRB received funding from the Brazilian National Council for Scientific and Technological Development (process no. 152,289/2018–6)Peer reviewe
Muslim Profiles Post-9/11: Is Racial Profiling an Effective Counterterrorist Measure and Does it Violate the Right to be Free from Discrimination?
Language of Lullabies: The Russification and De-Russification of the Baltic States
This article argues that the laws for promotion of the national languages are a legitimate means for the Baltic states to establish their cultural independence from Russia and the former Soviet Union
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