1,169 research outputs found
Differentiation state-specific mitochondrial dynamic regulatory networks are revealed by global transcriptional analysis of the developing chicken lens.
The mature eye lens contains a surface layer of epithelial cells called the lens epithelium that requires a functional mitochondrial population to maintain the homeostasis and transparency of the entire lens. The lens epithelium overlies a core of terminally differentiated fiber cells that must degrade their mitochondria to achieve lens transparency. These distinct mitochondrial populations make the lens a useful model system to identify those genes that regulate the balance between mitochondrial homeostasis and elimination. Here we used an RNA sequencing and bioinformatics approach to identify the transcript levels of all genes expressed by distinct regions of the lens epithelium and maturing fiber cells of the embryonic Gallus gallus (chicken) lens. Our analysis detected more than 15,000 unique transcripts expressed by the embryonic chicken lens. Of these, more than 3000 transcripts exhibited significant differences in expression between lens epithelial cells and fiber cells. Multiple transcripts coding for separate mitochondrial homeostatic and degradation mechanisms were identified to exhibit preferred patterns of expression in lens epithelial cells that require mitochondria relative to lens fiber cells that require mitochondrial elimination. These included differences in the expression levels of metabolic (DUT, PDK1, SNPH), autophagy (ATG3, ATG4B, BECN1, FYCO1, WIPI1), and mitophagy (BNIP3L/NIX, BNIP3, PARK2, p62/SQSTM1) transcripts between lens epithelial cells and lens fiber cells. These data provide a comprehensive window into all genes transcribed by the lens and those mitochondrial regulatory and degradation pathways that function to maintain mitochondrial populations in the lens epithelium and to eliminate mitochondria in maturing lens fiber cells
A survey of weather information possessed by thirty-two pupils randomly selected from sixth and eleventh grades and from special classes
Thesis (Ed.M.)--Boston Universit
Introduction of a simple experiment for the undergraduate organic chemistry laboratory demonstrating the Lewis acid and shape-selective properties of zeolite Na-Y
A simple, inexpensive, discovery-based experiment for undergraduate organic laboratories has been developed that demonstrates the Lewis acid and shape-selective properties of zeolites. Calcined zeolite Na-Y promotes the electrophilic aromatic bromination of toluene with a significantly higher para/ortho ratio than observed under conventional conditions. The experiment can be completed in one three-hour laboratory period. The zeolite can be recovered and regenerated for later reuse. A broad range of organic course topics from orientation in electrophilic aromatic substitution to photochemistry can be discussed
Contexts of diffusion: Adoption of research synthesis in Social Work and Women's Studies
Texts reveal the subjects of interest in research fields, and the values,
beliefs, and practices of researchers. In this study, texts are examined
through bibliometric mapping and topic modeling to provide a birds eye view of
the social dynamics associated with the diffusion of research synthesis methods
in the contexts of Social Work and Women's Studies. Research synthesis texts
are especially revealing because the methods, which include meta-analysis and
systematic review, are reliant on the availability of past research and data,
sometimes idealized as objective, egalitarian approaches to research
evaluation, fundamentally tied to past research practices, and performed with
the goal informing future research and practice. This study highlights the
co-influence of past and subsequent research within research fields;
illustrates dynamics of the diffusion process; and provides insight into the
cultural contexts of research in Social Work and Women's Studies. This study
suggests the potential to further develop bibliometric mapping and topic
modeling techniques to inform research problem selection and resource
allocation.Comment: To appear in proceedings of the 2014 International Conference on
Social Computing, Behavioral-Cultural Modeling, and Prediction (SBP2014
Scaling in cognitive performance reflects multiplicative multifractal cascade dynamics
Self-organized criticality purports to build multi-scaled structures out of local interactions. Evidence of scaling in various domains of biology may be more generally understood to reflect multiplicative interactions weaving together many disparate scales. The self-similarity of power-law scaling entails homogeneity: fluctuations distribute themselves similarly across many spatial and temporal scales. However, this apparent homogeneity can be misleading, especially as it spans more scales. Reducing biological processes to one power-law relationship neglects rich cascade dynamics. We review recent research into multifractality in executive-function cognitive tasks and propose that scaling reflects not criticality but instead interactions across multiple scales and among fluctuations of multiple sizes
Visualization of oxytocin release that mediates paired pulse facilitation in hypothalamic pathways to brainstem autonomic neurons
Recent work has shown that oxytocin is involved in more than lactation and uterine contraction. The paraventricular nucleus of the hypothalamus (PVN) contains neuroendocrine neurons that control the release of hormones, including vasopressin and oxytocin. Other populations of PVN neurons do not release hormones, but rather project to and release neurotransmitters onto other neurons in the CNS involved in fluid retention, thermoregulation, sexual behavior and responses to stress. Activation of oxytocin receptors can be cardioprotective and reduces the adverse cardiovascular consequences of anxiety and stress, yet how oxytocin can affect heart rate and cardiac function is unknown. While anatomical work has shown the presence of peptides, including oxytocin, in the projections from the PVN to parasympathetic nuclei, electrophysiological studies to date have only demonstrated release of glutamate and activation of fast ligand gated receptors in these pathways. In this study, using rats, we directly show, using sniffer CHO cells that express oxytocin receptors and the Ca2+ indicator R-GECO, that optogenetic activation of channelrhodopsin-2 (ChR2) expressing PVN fibers in the brainstem activates oxytocin receptors in the dorsomotor nucleus of the vagus (DMNV). We also demonstrate that while a single photoactivation of PVN terminals only activates glutamatergic receptors in brainstem cardiac vagal neurons (CVNs), neurons that dominate the neural control of heart rate, both the paired pulse facilitation, and sustained enhancement of glutamate release in this pathway is mediated by activation of oxytocin receptors. Our results provide direct evidence that a pathway from the PVN likely releases oxytocin and enhances short-term plasticity of this critical autonomic connection
NASA's Current Evidence and Hypothesis for the Visual Impairment and Intracranial Pressure Risk
While 40 years of human spaceflight exploration has reported visual decrement to a certain extent in a subgroup of astronauts, recent data suggests that there is indeed a subset of crewmembers that experience refraction changes (hyperoptic shift), cotton wool spot formation, choroidal fold development, papilledema, optic nerve sheath distention and/or posterior globe flattening with varying degrees of severity and permanence. Pre and postflight ocular measures have identified a potential risk of permanent visual changes as a result of microgravity exposure, which has been defined as the Visual Impairment and Intracranial Pressure risk (VIIP). The combination of symptoms are referred to as the VIIP syndrome. It is thought that the ocular structural and optic nerve changes are caused by events precipitated by the cephalad fluid shift crewmembers experience during long-duration spaceflight. Three important systems, ocular, cardiovascular, and central nervous, seem to be involved in the development of symptoms, but the etiology is still under speculation. It is believed that some crewmembers are more susceptible to these changes due to genetic/anatomical predisposition or lifestyle (fitness) related factors. Future research will focus on determining the etiology of the VIIP syndrome and development of mechanisms to mitigate the spaceflight risk
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The Second Opening of the Waste Isolation Pilot Plant? Review of Salient Characteristics and Unique Operational Considerations for Remote Handled Transuranic Waste
The U.S. Department of Energy (DOE) intends to dispose of remote handled (RH) transuranic (TRU) waste at the Waste Isolation Pilot Plant (WIPP) beginning in 2005. (1) Four principle regulatory agencies are involved in the process of approving the RH TRU waste activities. The DOE is responsible for operational activities. The U. S. Nuclear Regulatory Commission (NRC) approves the design and use of shipping containers. The U.S. Environmental Protection Agency (EPA) is responsible for assuring safe and environmentally effective long-term disposal of the radioactive component of the waste and operational environmental monitoring. The New Mexico Environment Department (NMED) is responsible for the handling and the disposal of the non-radioactive hazardous component of the waste. The Environmental Evaluation Group (EEG) is responsible for performing independent technical oversight of all WIPP activities, and will comment on documents and practices for the various regulated RH TRU waste activities. The DOE has already obtained the necessary approvals from the NRC, and has submitted a Class 3 Modification request to the NMED. On December 16, 2002 the DOE Carlsbad Field Office (CBFO) provided the EPA with a notice of proposed change, in accordance with 40 CFR 194.4 (b) (3), to receive and dispose of remote handled transuranic waste. (2) WIPP procedures for the management of RH TRU waste at the site are being developed. While there are no issues with current NRC Certificates of Compliance for the RH TRU waste shipping containers, it is likely that there will be some controversy over other aspects of the currently planned RH TRU waste program. These issues may include: (1) the published RH TRU waste inventory, (2) the characterization of the radionuclide portion of the waste, for which one planned method is to use dose-to-Curie conversions, and (3) the plans to use bounding estimates for the hazardous portion of the WIPP waste, rather than measuring VOCs on a container-by-container basis or by representative sampling as is done for contact handled transuranic (CH TRU) waste. This paper discusses the currently planned process and the possible issues related to the DOE's efforts to dispose RH TRU waste at the WIPP
TGF-β Sustains Tumor Progression through Biochemical and Mechanical Signal Transduction.
Transforming growth factor β (TGF-β) signaling transduces immunosuppressive biochemical and mechanical signals in the tumor microenvironment. In addition to canonical SMAD transcription factor signaling, TGF-β can promote tumor growth and survival by inhibiting proinflammatory signaling and extracellular matrix (ECM) remodeling. In this article, we review how TGF-β activated kinase 1 (TAK1) activation lies at the intersection of proinflammatory signaling by immune receptors and anti-inflammatory signaling by TGF-β receptors. Additionally, we discuss the role of TGF-β in the mechanobiology of cancer. Understanding how TGF-β dampens proinflammatory responses and induces pro-survival mechanical signals throughout cancer development is critical for designing therapeutics that inhibit tumor progression while bolstering the immune response
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