3,519 research outputs found
Anterior segment photography - An evaluation of the various techniques and films
This paper investigates some of the various methods of photographing the anterior segment of the eye. It deals with slit lamp photography, macrophotography, and hand-held photography and points out the advantages and disadvantages of each. Various films including color negative, color slide, and infra-red film were also employed in order to determine the benefits of each. The Hentor slit lamp is dealt with in particular in order to develop photographic attachments for it. This paper also explains why ocular photography is important and how to do it
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Energetics and mechanics of swing phase during terrestrial locomotion
Previous attempts to understand the factors affecting the energetic cost of locomotion have found a direct link between the energetic cost and the mechanical work done during periods when the limb is in contact with the ground. However, when the limb is not in contact with the ground during the swing phase, this link between mechanical work and energetic cost disappears. I examined the mechanics of swing to explore the possibility of passive mechanisms allowing for the performance of mechanical work with little to no energetic cost during swing. Previous studies have ruled out the possibility of a pendulum exchange of gravitational potential and kinetic energy during human locomotion because the swing frequencies are too high. I added the accelerations of the body during stance to the swinging lower limb to determine if the frequency where the pendulum-like exchange of energy occurs could be increased. These accelerations increased the frequency where energy exchange occurs and thereby reduced the work required to swing the human lower limb. The pendulum-like exchange of energy reduces the work required for swing, but some work is still required. To explore how the remaining work for swing was produced I examined two muscles potentially involved in producing an extension moment about the intertarsal joint of turkeys during swing. The only muscle providing force for intertarsal joint extension during swing was the lateral head of the gastrocnemius (LG). A comparison of the in situ length-tension curve and in vivo operating lengths during swing revealed the LG operated at long lengths on the descending limb of the length tension curve during swing. Finally I characterized the force-velocity curve of the LG and found the muscle to have mechanical properties within the range previously determined for other vertebrates. In conclusion, I determined a passive mechanism which could reduce the required mechanical work of swing and thereby explain part of the apparent lack of a link between mechanical work and energetic cost of swing. In addition, results from these studies suggest the remaining work necessary for swing may be provided by active contraction of muscle
Intracellular calcium movements during relaxation and recovery of superfast muscle fibers of the toadfish swimbladder
© The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of General Physiology 143 (2014): 605-620, doi:10.1085/jgp.201411160.The mating call of the Atlantic toadfish is generated by bursts of high-frequency twitches of the superfast twitch fibers that surround the swimbladder. At 16°C, a calling period can last several hours, with individual 80â100-Hz calls lasting âŒ500 ms interleaved with silent periods (intercall intervals) lasting âŒ10 s. To understand the intracellular movements of Ca2+ during the intercall intervals, superfast fibers were microinjected with fluo-4, a high-affinity fluorescent Ca2+ indicator, and stimulated by trains of 40 action potentials at 83 Hz, which mimics fiber activity during calling. The fluo-4 fluorescence signal was measured during and after the stimulus trains; the signal was also simulated with a kinetic model of the underlying myoplasmic Ca2+ movements, including the binding and transport of Ca2+ by the sarcoplasmic reticulum (SR) Ca2+ pumps. The estimated total amount of Ca2+ released from the SR during a first stimulus train is âŒ6.5 mM (concentration referred to the myoplasmic water volume). At 40 ms after cessation of stimulation, the myoplasmic free Ca2+ concentration ([Ca2+]) is below the threshold for force generation (âŒ3 ”M), yet the estimated concentration of released Ca2+ remaining in the myoplasm (Î[CaM]) is large, âŒ5 mM, with âŒ80% bound to parvalbumin. At 10 s after stimulation, [Ca2+] is âŒ90 nM (three times the assumed resting level) and Î[CaM] is âŒ1.3 mM, with 97% bound to parvalbumin. Ca2+ movements during the intercall interval thus appear to be strongly influenced by (a) the accumulation of Ca2+ on parvalbumin and (b) the slow rate of Ca2+ pumping that ensues when parvalbumin lowers [Ca2+] near the resting level. With repetitive stimulus trains initiated at 10-s intervals, Ca2+ release and pumping come quickly into balance as a result of the stability (negative feedback) supplied by the increased rate of Ca2+ pumping at higher [Ca2+].This work was supported by a grant to S.M. Baylor from the National Institutes of Health (GM 086167) and a grant to L.C. Rome from the National Science Foundation (IOS-1145981)
Defects in nematic membranes can buckle into pseudospheres
A nematic membrane is a sheet with embedded orientational order, which can
occur in biological cells, liquid crystal films, manufactured materials, and
other soft matter systems. By formulating the free energy of nematic films
using tensor contractions from differential geometry, we elucidate the elastic
terms allowed by symmetry, and indicate differences from hexatic membranes. We
find that topological defects in the orientation field can cause the membrane
to buckle over a size set by the competition between surface tension and
in-plane elasticity. In the absence of bending rigidity the resulting shape is
universal, known as a parabolic pseudosphere or a revolved tractrix. Bending
costs oppose such buckling and modify the shape in a predictable manner. In
particular, the anisotropic rigidities of nematic membranes lead to different
shapes for aster and vortex defects, in principle enabling measurement of
couplings specific to nematic membranes.Comment: 9 pages, 3 figure
Chapter 3 Wetland Design and Development
The history of efforts to design and develop wetland sites is extensive and rich, especially in the United States. This chapter provides an annotated view of the current state of wetland design and recommends an approach to future efforts using âHydrogeomorphic Methodology.â Experience over the past century indicates that the most important part of wetland design and development is upfront work to: (1) determine what type of wetland historically occurred in, and is appropriate for a site; (2) understand and attempt to emulate the key ecological processes that created and sustained specific wetland types; (3) compare historical landscapes and wetland attributes with contemporary landscape and site conditions to understand remediating needs; and (4) determine management objectives and capabilities. The foundation for hydrogeomorphic assessments is analysis of historical and current information about geology and geomorphology, soils, topography and elevation, hydrological regimes, plant and animal communities, and physical anthropogenic features. The availability of this information is discussed and the sequence of actions used to prepare hydrogeomorphic matrices of potential historical vegetation communities and maps is provided as in application of information. Specific considerations for designing wetland infrastructure and restoring wetland vegetation are reviewed. An example of a wetland restoration project for the Duck Creek Conservation Area, Missouri is provided to demonstrate use of the hydrogeomorphic approach. We believe that future wetland design and development strategies should include the following actions: (1) wetland conservation must seek to achieve incremental gains at landscape-level scales; (2) the foundation of wetland design is determining the appropriate wetland type for the site being considered; (3) wetland designs should seek to restore and emulate historical form and process as completely as possible and to make systems as self-sustainable as possible; and (4) future design and development of wetlands must anticipate change related to climate, land uses, encroachments, and water availability and rights
Chapter 3 Wetland Design and Development
The history of efforts to design and develop wetland sites is extensive and rich, especially in the United States. This chapter provides an annotated view of the current state of wetland design and recommends an approach to future efforts using âHydrogeomorphic Methodology.â Experience over the past century indicates that the most important part of wetland design and development is upfront work to: (1) determine what type of wetland historically occurred in, and is appropriate for a site; (2) understand and attempt to emulate the key ecological processes that created and sustained specific wetland types; (3) compare historical landscapes and wetland attributes with contemporary landscape and site conditions to understand remediating needs; and (4) determine management objectives and capabilities. The foundation for hydrogeomorphic assessments is analysis of historical and current information about geology and geomorphology, soils, topography and elevation, hydrological regimes, plant and animal communities, and physical anthropogenic features. The availability of this information is discussed and the sequence of actions used to prepare hydrogeomorphic matrices of potential historical vegetation communities and maps is provided as in application of information. Specific considerations for designing wetland infrastructure and restoring wetland vegetation are reviewed. An example of a wetland restoration project for the Duck Creek Conservation Area, Missouri is provided to demonstrate use of the hydrogeomorphic approach. We believe that future wetland design and development strategies should include the following actions: (1) wetland conservation must seek to achieve incremental gains at landscape-level scales; (2) the foundation of wetland design is determining the appropriate wetland type for the site being considered; (3) wetland designs should seek to restore and emulate historical form and process as completely as possible and to make systems as self-sustainable as possible; and (4) future design and development of wetlands must anticipate change related to climate, land uses, encroachments, and water availability and rights
Influence of Crohnâs disease related polymorphisms in innate immune function on ileal microbiome
We have previously identified NOD2 genotype and inflammatory bowel diseases (IBD) phenotype, as associated with shifts in the ileal microbiome (âdysbiosisâ) in a patient cohort. Here we report an integrative analysis of an expanded number of Crohn's disease (CD) related genetic defects in innate immune function (NOD2, ATG16L1, IRGM, CARD9, XBP1, ORMDL3) and composition of the ileal microbiome by combining the initial patient cohort (Batch 1, 2005â2010, n = 165) with a second consecutive patient cohort (Batch 2, 2010â2012, n = 118). These combined patient cohorts were composed of three non-overlapping phenotypes: 1.) 106 ileal CD subjects undergoing initial ileocolic resection for diseased ileum, 2.) 88 IBD colitis subjects without ileal disease (predominantly ulcerative colitis but also Crohnâs colitis and indeterminate colitis, and 3.) 89 non-IBD subjects. Significant differences (FDR C. difficile infection, and NOD2 genotype on ileal dysbiosis in the expanded analysis. The relative abundance of the Proteobacteria phylum was positively associated with ileal CD and colitis phenotypes, but negatively associated with NOD2R genotype. Additional associations with ORMDL3 and XBP1 were detected at the phylum/subphylum level. IBD medications, such as immunomodulators and anti-TNFα agents, may have a beneficial effect on reversing dysbiosis associated with the IBD phenotype. Exploratory analysis comparing microbial composition of the disease unaffected region of the resected ileum between 27 ileal CD patients who subsequently developed endoscopic recurrence within 6â12 months versus 34 patients who did not, suggested that microbial biomarkers in the resected specimen helped stratify patients with respect to risk of post-surgical recurrence.</div
Effect of Prior Anterior Superior Iliac Spine Compression Testing on Second Assessor Findings: Implications for Inter-Examiner Reliability Testing
BACKGROUND: Osteopathic physicians use palpation to diagnose sacroiliac joint somatic dysfunction (SD) -- including the Anterior Superior Iliac Spine (ASIS) Compression Test for dysfunctional side lateralization. (Literature suggests right-sided lateralization in 80% of asymptomatic individuals). Accurate, reliable tests are crucial however to diagnose SD and kappa (Îș) analysis is a gold-standard to determine the degree of interexaminer reliability for tests. Few studies have examined the effect the palpatory examination has on subsequent diagnostic findings and therefore on Îș-values
Inter-Examiner Reliability of an Anterior Superior Iliac Spine Compression Test used to Lateralize Pelvic Somatic Dysfunction to the Right Side or Not
BACKGROUND: Osteopathic physicians use a number of palpatory structural examinations to diagnose pelvic somatic dysfunction (SD). They may elect to use the Anterior Superior Iliac Spine (ASIS) Compression Test to lateralize the dysfunctional side. Accurate, reliable tests are crucial to neuromusculoskeletal diagnosis and this study employs the kappa (Îș) analysis protocol recommended for assessing interexaminer reliability of manual medicine tests (published by the FĂ©dĂ©ration Internationale de MĂ©decine Manuelle [FIMM]). Îș-values â„0.40 (moderate agreement) are considered to be acceptable for use in the clinical setting
The Use of Objective Data to Improve Interexaminer Reliability
BACKGROUND: In Osteopathic Manipulative Medicine (OMM) and Manual/Musculoskeletal Medicine (MMM), palpatory diagnosis is performed on a regular basis to diagnose somatic dysfunction (SD). This examination requires careful and precise touch coupled with subjective interpretation by individual examiners who may have been trained to evaluate SD through different methods. Interexaminer reliability studies aim to minimize variance by providing quantifiable scientific data to evaluate specific test protocols which can then be taught to practitioners. In a previous PCOM study, two examiners independently diagnosed innominate bone dysfunction lateralized using the ASIS compression test on a large group of subjects. A pressure monitoring system (IsoTOUCHÂź, Chattanooga TN) has been used in various studies at the PCOM Human Performance & Biomechanics Laboratory (Kuchera, Jean et al 2006 & Kuchera, Vardy et al 2005) to quantify or standardize forces used in palpatory diagnosis or OMM/MMM treatment applications. This study gathered data during the tesing phase of a new and improved model of this system, using the protocol of the previous ASIS interexaminer reliability study. The data collected during standardization of the system was analyzed in the same manner as the previous study to compare the results of interexaminer reliability to results achieved using live data feed for baseline pressure synchronization between examiners
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