2,113 research outputs found
Synaptic Hyaluronan Synthesis and CD44-Mediated Signaling Coordinate Neural Circuit Development
The hyaluronan-based extracellular matrix is expressed throughout nervous system development and is well-known for the formation of perineuronal nets around inhibitory interneurons. Since perineuronal nets form postnatally, the role of hyaluronan in the initial formation of neural circuits remains unclear. Neural circuits emerge from the coordinated electrochemical signaling of excitatory and inhibitory synapses. Hyaluronan localizes to the synaptic cleft of developing excitatory synapses in both human cortical spheroids and the neonatal mouse brain and is diminished in the adult mouse brain. Given this developmental-specific synaptic localization, we sought to determine the mechanisms that regulate hyaluronan synthesis and signaling during synapse formation. We demonstrate that hyaluronan synthase-2, HAS2, is sufficient to increase hyaluronan levels in developing neural circuits of human cortical spheroids. This increased hyaluronan production reduces excitatory synaptogenesis, promotes inhibitory synaptogenesis, and suppresses action potential formation. The hyaluronan receptor, CD44, promotes hyaluronan retention and suppresses excitatory synaptogenesis through regulation of RhoGTPase signaling. Our results reveal mechanisms of hyaluronan synthesis, retention, and signaling in developing neural circuits, shedding light on how disease-associated hyaluronan alterations can contribute to synaptic defects.ECU Open Access Publishing Support Fun
Stem cell models of human synapse development and degeneration
Many brain disorders exhibit altered synapse formation in development or syn- apse loss with age. To understand the complexities of human synapse development and degeneration, scientists now engineer neurons and brain organoids from human-induced pluripotent stem cells (hIPSC). These hIPSC-derived brain models develop both excitatory and inhibitory synapses and functional synaptic activity. In this review, we address the ability of hIPSC-derived brain models to recapitulate synapse development and insights gained into the molecular mechanisms underlying synaptic alterations in neuronal disorders. We also discuss the potential for more accurate human brain models to advance our understanding of synapse development, degeneration, and therapeutic responses
Strengthening Integration of Land Use Research and Outreach Through Innovative Web Technology
The University of Connecticut has long used geospatial information as a component of its Extension programs on land use policy. In recent years, increased use of remote sensing and geographic information systems has created a technology gap, as sources of data outpace the ability of many communities to make use of it. The NEMO program has developed several Web sites that attempt to bridge this gap. Connecticut\u27s Changing Landscape uses a range of approaches to disseminate information to audiences of varying geospatial sophistication. These techniques help Extension to serve a broader audience and also strengthen the ties between research and outreach
Development of a Fabry-Perot Interferometer for Ultra-Precise Measurements of Column CO2
A passive Fabry-Perot based instrument is described for detecting column CO2 through absorption measurements at 1.58 microns . In this design, solar flux reaches the instrument platform and is directed through two channels. In the first channel, transmittance fi5nges from a Fabry-Perot interferometer are aligned with CO2 absorption lines so that absorption due to CO2 is primarily detected. The second channel encompasses the same frequency region as the first, but is comparatively more sensitive to changes in the solar flux than absorption due to CO2. The ratio of these channels is sensitive to changes in the total CO2 column, but not to changes in solar flux. This inexpensive instrument will offer high precision measurements (error 4%) in a compact package. Design of this instrument and preliminary ground-based measurements of column CO2 are presented here as well as strategies for deployment on aircraft and satellite platforms
Differential Radiometers Using Fabry-Perot Interferometric Technique for Remote Sensing of Greenhouse Gases
A new type of remote sensing radiometer based upon the Fabry-Perot interferometric technique has been developed at NASA's Goddard Space Flight Center and tested from both ground and aircraft platform. The sensor uses direct or reflected sunlight and has channels for measuring column concentration of carbon dioxide at 1570 nm, oxygen lines sensitive to pressure and temperature at 762 and 768 nm, and water vapor (940 nm). A solid Fabry-Perot etalon is used as a tunable narrow bandpass filter to restrict the measurement to the gas of interest's absorption bands. By adjusting the temperature of the etalon, which changes the index of refraction of its material, the transmission fringes can be brought into nearly exact correspondence with absorption lines of the particular species. With this alignment between absorption lines and fringes, changes in the amount of a species in the atmosphere strongly affect the amount of light transmitted by the etalon and can be related to gas concentration. The technique is applicable to different chemical species. We have performed simulations and instrument design studies for CH4, "Cot isotope, and CO detection. Index Terms- Absorbing media, Atmospheric measurements, Fabry-Perot interferometers, Optical interferometry, Remote sensing
A Systematic Online Living Evidence Summary of experimental Alzheimer's disease research
BACKGROUND: Despite extensive investment, the development of effective treatments for Alzheimer's disease (AD) has been largely unsuccessful. To improve translation, it is crucial to ensure the quality and reproducibility of foundational evidence generated from laboratory models. Systematic reviews play a key role in providing an unbiased overview of the evidence, assessing rigour and reporting, and identifying factors that influence reproducibility. However, the sheer pace of evidence generation is prohibitive to evidence synthesis and assessment.NEW METHOD: To address these challenges, we have developed AD-SOLES, an integrated workflow of automated tools that collect, curate, and visualise the totality of evidence from in vivo experiments.RESULTS: AD-SOLES is a publicly accessible interactive dashboard aiming to surface and expose data from in vivo experiments. It summarises the latest evidence, tracks reporting quality and transparency, and allows research users to easily locate evidence relevant to their specific research question.COMPARISON WITH EXISTING METHODS: Using automated screening methodologies within AD-SOLES, systematic reviews can begin at an accelerated starting point compared to traditional approaches. Furthermore, through text-mining approaches within the full-text of publications, users can identify research of interest using specific models, outcomes, or interventions without relying on details in the title and/or abstract.CONCLUSIONS: By automating the collection, curation, and visualisation of evidence from in vivo experiments, AD-SOLES addresses the challenges posed by the rapid pace of evidence generation. AD-SOLES aims to offer guidance for research improvement, reduce research waste, highlight knowledge gaps, and support informed decision making for researchers, funders, patients, and the public.</p
Self-reported illness among Boston-area international travelers: A prospective study
This is the Accepted Manuscript version and was published in final edited form as: Travel Med Infect Dis. 2016 ; 14(6): 604–613. doi:10.1016/j.tmaid.2016.09.009.BACKGROUND: The Boston Area Travel Medicine Network surveyed travelers on travel-related health problems.
METHODS: Travelers were recruited 2009-2011 during pre-travel consultation at three clinics. The investigation included pre-travel data, weekly during-travel diaries, and a post-travel questionnaire. We analyzed demographics, trip characteristics, health problems experienced, and assessed the relationship between influenza vaccination, influenza prevention advice, and respiratory symptoms.
RESULTS:Of 987 enrolled travelers, 628 (64%) completed all surveys, of which 400 (64%) reported health problems during and/or after travel; median trip duration was 12 days. Diarrhea affected the most people during travel (172) while runny/stuffy nose affected the most people after travel (95). Of those with health problems during travel, 25% stopped or altered plans; 1% were hospitalized. After travel, 21% stopped planned activities, 23% sought physician or other health advice; one traveler was hospitalized. Travelers who received influenza vaccination and influenza prevention advice had lower rates of respiratory symptoms than those that received influenza prevention advice alone (18% vs 28%, P = 0.03).
CONCLUSIONS:A large proportion of Boston-area travelers reported health problems despite pre-travel consultation, resulting in inconveniences. The combination of influenza prevention advice and influenza immunization was associated with fewer respiratory symptoms than those who received influenza prevention advice alone
Travelers’ diarrhea and other gastrointestinal symptoms among Boston-area international travelers
INTRODUCTION: Travelers' diarrhea (TD) and non-TD gastrointestinal (GI) symptoms are common among international travelers. In a study of short-term travelers from Switzerland to developing countries, the most common symptom experienced was severe diarrhea (8.5%) followed by vomiting or abdominal cramps (4%).1 GI illnesses were the most frequently reported diagnoses (34%) among ill-returned travelers to GeoSentinel clinics.2 Of those returning to U.S. GeoSentinel clinics, acute diarrhea (30%) was the most common diagnosis.3 In one cohort of U.S. travelers, 46% reported diarrhea.4 GI illnesses can last from 2 days to weeks or longer,5 disrupting plans during travel or after returning home. Eighty percent of those who experienced diarrhea during travel treated themselves with medication and 6% sought medical care.
METHODS: The Boston Area Travel Medicine Network (BATMN) is a research collaboration of travel clinics in the greater Boston area representing urban-, suburban-, academic-, and university-affiliated facilities. A convenience sample of travelers ≥ 18 years of age attending three BATMN clinics between 2009 and 2011 for pre-travel consultations completed pre-travel surveys, at least one survey weekly during travel, and a post-travel survey 2–4 weeks after return. Travelers were asked to complete a survey at the end of each week of their trip. Institutional review board approvals were obtained at all sites and the Centers for Disease Control and Prevention, and participants provided written informed consent. Information collected included demographic and trip characteristics, vaccines and medications recommended/prescribed before travel, medications taken during travel, dietary practices during travel (consumption of tap water, ice in drinks, unpasteurized dairy products, and salads), symptoms experienced, and impact of illness during and after travel. Vaccinations, prescriptions, and travel health advice given during the pre-travel consultation were recorded by a clinician, and the remainder of the surveys were completed by the traveler. Data were entered into a password-protected database (CS Pro, U.S. Census Bureau, Washington, DC).
RESULTS: We enrolled 987 travelers; 628 (64%) completed all three parts (pre-, during, and post-travel) and were included in the study. Comparison of the 628 to the 359 who did not complete all three parts (noncompleters) revealed no differences, except that completion rates were higher for white travelers than all other racial/ethnic groups (P < 0.001) and for older travelers (median age 47 years versus 32 years in noncompleters, P < 0.001).11 Of those 628 travelers, 208 (33%) experienced TD, 45 (7%) experienced non-TD GI symptoms, 147 (23%) experienced non-GI symptoms, and 228 (36%) did not experience any symptoms during or after travel. Of the 208 with TD, 140 (67%) reported diarrhea as their only symptom, whereas 33 (16%) also experienced nausea/vomiting, 23 (11%) abdominal pain, and 27 (13%) fever (Table 1). Of the 45 who reported non-TD GI symptoms, 21 (47%) experienced nausea/vomiting, 19 (42%) experienced constipation, and 10 (22%) experienced abdominal pain during or after travel (Table 2). Almost all travelers (99%) received advice about food and water precautions and diarrhea management during pre-travel consultation
A Hollow-Waveguide Gas Correlation Radiometer for Ultra-Precise Column Measurements of Formaldehyde on Mars
We present preliminary results in the development of a miniaturized gas correlation radiometer that implements a hollow-core optical fiber (hollow waveguide) gas correlation cell. The substantial reduction in mass and volume of the gas correlation cell makes this technology appropriate for an orbital mission -- capable of pinpointing sources of trace gases in the Martian atmosphere. Here we demonstrate a formaldehyde (H2CO) sensor and report a detection limit equivalent to approximately 30 ppb in the Martian atmosphere. The relative simplicity of the technique allows it to be expanded to measure a range of atmospheric trace gases of interest on Mars such as methane (CH4), water vapour (H2O), deuterated water vapour (HDO), and methanol (CH3OH). Performance of a formaldehyde instrument in a Mars orbit has been simulated assuming a 3 meter long, 1000 micron inner diameter hollow-core fiber gas correlation cell, a 92.8 degree sun-synchronous orbit from 400 km with a horizontal sampling scale of 10 km x 10 km. Initial results indicate that for one second of averaging, a detection limit of 1 ppb is possible
Development of a Miniaturized Hollow-Waveguide Gas Correlation Radiometer for Trace Gas Measurements in the Martian Atmosphere
We present preliminary results in the development of a miniaturized gas correlation radiometer (GCR) for column trace gas measurements in the Martian atmosphere. The GCR is designed as an orbiting instrument capable of mapping multiple trace gases and identifying active regions on the Mars surface
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