272 research outputs found
Home on the Range: Aging in Place in Rural Kansas
This study is a product of research on aging in place in the rural2 Midwest. Here we take the perspective of social demography to investigate long-term trends of aging in rural Kansas. Using county level historical statistics and in-depth analysis of the 2000 Census, we put these trends into the context of aging in the United States, and present a statistical analysis of aging and economic development. The data for this study come from various sources at the U.S. Census Bureau and the Economic Research Service (E.R.S.) division of the U.S.D.A. We also address the community development challenges posed by aging in place. This latter subject will be presented as an overview since our current research activity is conducting case studies addressing community development issues in greater depth
Lattice Kinetics of Diffusion-Limited Coalescence and Annihilation with Sources
We study the 1D kinetics of diffusion-limited coalescence and annihilation
with back reactions and different kinds of particle input. By considering the
changes in occupation and parity of a given interval, we derive sets of
hierarchical equations from which exact expressions for the lattice coverage
and the particle concentration can be obtained. We compare the mean-field
approximation and the continuum approximation to the exact solutions and we
discuss their regime of validity.Comment: 24 pages and 3 eps figures, Revtex, accepted for publication in J.
Phys.
Visualization of Bacterial Protein Complexes Labeled with Fluorescent Proteins and Nanobody Binders for STED Microscopy
In situ visualization of molecular assemblies near their macromolecular scale is a powerful tool to investigate fundamental cellular processes. Super-resolution light microscopies (SRM) overcome the diffraction limit and allow researchers to investigate molecular arrangements at the nanoscale. However, in bacterial cells, visualization of these assemblies can be challenging because of their small size and the presence of the cell wall. Thus, although conceptually promising, successful application of SRM techniques requires careful optimization in labeling biochemistry, fluorescent dye choice, bacterial biology and microscopy to gain biological insights. Here, we apply Stimulated Emission Depletion (STED) microscopy to visualize cell division proteins in bacterial cells, specifically E. coli and B. subtilis. We applied nanobodies that specifically recognize fluorescent proteins, such as GFP, mCherry2 and PAmCherry, fused to targets for STED imaging and evaluated the effect of various organic fluorescent dyes on the performance of STED in bacterial cells. We expect this research to guide scientists for in situ macromolecular visualization using STED in bacterial systems
Posterior Approach To Kidney Dissection: An Old Surgical Approach For Integrated Medical Curricula
Integrated medical curricular changes are altering the historical regional anatomy approach to abdominal dissection. The renal system is linked physiologically and biochemically to the cardiovascular and respiratory systems, yet anatomist often approach the urinary system as part of the abdomen and pelvic regions. As part of an integrated curriculum, the renal system must be covered relatively quickly after the thorax in the cadaver lab, often without the opportunity to fully appreciate the rest of the abdominal contents. This paper provides dissection instructions that follow the one of the historical surgical approaches for nephrectomy, including preservation of the posterior abdominal wall neurovasclature. Dissection procedures were developed for first year medical students, intending this posterior approach to the kidneys to be their first introduction to the renal system. It has been successfully implemented with first year medical students at the University of New England, College of Osteopathic Medicine. Utilizing this posterior approach to the kidney enabled the study of the anatomy of the kidneys, suprarenal glands and renal vessels, as well as the muscles of the lumbar spine, while maintaining the integrity of the anterior abdominal wall and peritoneal cavity for future gastrointestinal and reproductive system-based dissections
Preliminary Report: Evaluating the Potential of Archaeogeophysical Surveying on Viking Age and Medieval Sites in Greenland, 2 – 16 August, 2010
The primary goal of this research is to begin to overcome biases in the Greenlandic Norse archaeological record. Assessing the establishment dates and organization of Norse sites in Greenland is difficult because substantial cultural deposits can be hidden under deep windblown sand deposits as well as later occupations. Shallow geophysical methods were used to help recover information on the nature, extent and depth of subsurface cultural deposits. Assessing these site characteristics is a first step in overcoming the bias towards the later, the larger, and the more visible sites in the archaeological record.
Norse Greenland presents a relatively visible medieval landscape with many ruins preserved on the surface. Survey archaeologists have taken advantage of these conditions to do comprehensive surveys of Norse settlements producing inventories of farm buildings and settlements (Guldager, et al. 2002; Keller 1990). Coring surveys and excavation at known sites have demonstrated that some sites are buried under significant aeolian deposits and that areas within many other sites can be deep and contain ruins that are not visible on the surface. In many cases Viking Age deposits cannot be accessed by archaeological excavation, as this would damage later occupational phases. In these cases, application of archeogeophysics may be the only way to assess this unique cultural history. The identification, characterization, and dating of these subsurface architectural remains are critical to systematic survey programs and to the production of regional settlement patterns and chronologies that can help explain the ecological and political dynamics of Norse colonization, land use, and the eventual demise of Norse Greenland.
Over the past 10 years the Skagafjörður Archaeological Settlement Survey (SASS) has developed an intensive subsurface survey protocol to systematically recover, date, and characterize Viking Age landscapes in Iceland. While we believe the SASS subsurface protocol can be effective in Greenland there are many questions that must be resolved before any wide-scale application of the methods can be developed. The project set out to address two basic questions: (1) what is the actual subsurface record at Norse sites, and (2) which methods work best and how are they most effectively employed? In this initial investigation, we tested and adapted this protocol to conditions in Greenland. We hope that the preliminary test of these methods will significantly expand the range of sites and periods accessible to researchers working in Greenland and allow for new questions regarding the long-term political and environmental histories of the region.
The successful integration of archaeogeophysics with archaeological survey and excavation will result in a more holistic approach to the preservation of Norse archaeological sites in Greenland. These sites suffer from increased modern impacts resulting from mineral exploitation, sheep farming, and tourism. Additionally, there is now total summer sub-surface thaw and conditions that were once ideal for preserving organic remains are now deteriorating, especially in well-drained areas. In the coming years the Greenland National Museum will begin a program of scheduling and protecting some of these sites. We believe that the application of archaeogeophysics could be a great asset in determining which sites are in danger and worthy of preservation
Bacterial porin disrupts mitochondrial membrane potential and sensitizes host cells to apoptosis
The bacterial PorB porin, an ATP-binding beta-barrel protein of pathogenic Neisseria gonorrhoeae, triggers host cell apoptosis by an unknown mechanism. PorB is targeted to and imported by host cell mitochondria, causing the breakdown of the mitochondrial membrane potential (delta psi m). Here, we show that PorB induces the condensation of the mitochondrial matrix and the loss of cristae structures, sensitizing cells to the induction of apoptosis via signaling pathways activated by BH3-only proteins. PorB is imported into mitochondria through the general translocase TOM but, unexpectedly, is not recognized by the SAM sorting machinery, usually required for the assembly of beta-barrel proteins in the mitochondrial outer membrane. PorB integrates into the mitochondrial inner membrane, leading to the breakdown of delta psi m. The PorB channel is regulated by nucleotides and an isogenic PorB mutant defective in ATP-binding failed to induce delta psi m loss and apoptosis, demonstrating that dissipation of delta psi m is a requirement for cell death caused by neisserial infection
Comprehensive analysis of chemical and biological problems associated with browning agents used in aquatic studies
Inland waters receive and process large amounts of colored organic matter from the terrestrial surroundings. These inputs dramatically affect the chemical, physical, and biological properties of water bodies, as well as their roles as global carbon sinks and sources. However, manipulative studies, especially at ecosystem scale, require large amounts of dissolved organic matter with optical and chemical properties resembling indigenous organic matter. Here, we compared the impacts of two leonardite products (HuminFeed and SuperHume) and a freshly derived reverse osmosis concentrate of organic matter in a set of comprehensive mesocosm- and laboratory-scale experiments and analyses. The chemical properties of the reverse osmosis concentrate and the leonardite products were very different, with leonardite products being low and the reverse osmosis concentrate being high in carboxylic functional groups. Light had a strong impact on the properties of leonardite products, including loss of color and increased particle formation. HuminFeed presented a substantial impact on microbial communities under light conditions, where bacterial production was stimulated and community composition modified, while in dark potential inhibition of bacterial processes was detected. While none of the browning agents inhibited the growth of the tested phytoplankton Gonyostomum semen, HuminFeed had detrimental effects on zooplankton abundance and Daphnia reproduction. We conclude that the effects of browning agents extracted from leonardite, particularly HuminFeed, are in sharp contrast to those originating from terrestrially derived dissolved organic matter. Hence, they should be used with great caution in experimental studies on the consequences of terrestrial carbon for aquatic systems
Quantitative radiologic criteria for the diagnosis of lumbar spinal stenosis: a systematic literature review
Background: Beside symptoms and clinical signs radiological findings are crucial in the diagnosis of lumbar spinal stenosis (LSS). We investigate which quantitative radiological signs are described in the literature and which radilogical criteria are used to establish inclusion criteria in clincical studies evaluating different treatments in patients with lumbar spinal stenosis.
Methods: A literature search was performed in Medline, Embase and the Cochrane library to identify papers reporting on radiological criteria to describe LSS and systematic reviews investigating the effects of different treatment modalities.
Results: 25 studies reporting on radiological signs of LSS and four systematic reviews related to the evaluation of different treatments were found. Ten different parameters were identified to quantify lumbar spinal stenosis. Most often reported measures for central stenosis were antero-posterior diameter (< 10 mm) and cross-sectional area (< 70 mm2) of spinal canal. For lateral stenosis height and depth of the lateral recess, and for foraminal stenosis the foraminal diameter were typically used. Only four of 63 primary studies included in the systematic reviews reported on quantitative measures for defining inclusion criteria of patients in prognostic studies.
Conclusions: There is a need for consensus on well-defined, unambiguous radiological criteria to define lumbar spinal stenosis in order to improve diagnostic accuracy and to formulate reliable inclusion criteria for clinical studies
Listeriolysin O Is Necessary and Sufficient to Induce Autophagy during Listeria monocytogenes Infection
Recent studies have suggested that autophagy is utilized by cells as a protective mechanism against Listeria monocytogenes infection.However we find autophagy has no measurable role in vacuolar escape and intracellular growth in primary cultured bone marrow derived macrophages (BMDMs) deficient for autophagy (atg5-/-). Nevertheless, we provide evidence that the pore forming activity of the cholesterol-dependent cytolysin listeriolysin O (LLO) can induce autophagy subsequent to infection by L. monocytogenes. Infection of BMDMs with L. monocytogenes induced microtubule-associated protein light chain 3 (LC3) lipidation, consistent with autophagy activation, whereas a mutant lacking LLO did not. Infection of BMDMs that express LC3-GFP demonstrated that wild-type L. monocytogenes was encapsulated by LC3-GFP, consistent with autophagy activation, whereas a mutant lacking LLO was not. Bacillus subtilis expressing either LLO or a related cytolysin, perfringolysin O (PFO), induced LC3 colocalization and LC3 lipidation. Further, LLO-containing liposomes also recruited LC3-GFP, indicating that LLO was sufficient to induce targeted autophagy in the absence of infection. The role of autophagy had variable effects depending on the cell type assayed. In atg5-/- mouse embryonic fibroblasts, L. monocytogenes had a primary vacuole escape defect. However, the bacteria escaped and grew normally in atg5-/- BMDMs.We propose that membrane damage, such as that caused by LLO, triggers bacterial-targeted autophagy, although autophagy does not affect the fate of wild-type intracellular L. monocytogenes in primary BMDMs
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