201 research outputs found

    Systems and methods for correcting optical reflectance measurements

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    We disclose measurement systems and methods for measuring analytes in target regions of samples that also include features overlying the target regions. The systems include: (a) a light source; (b) a detection system; (c) a set of at least first, second, and third light ports which transmit light from the light source to a sample and receive and direct light reflected from the sample to the detection system, generating a first set of data including information corresponding to both an internal target within the sample and features overlying the internal target, and a second set of data including information corresponding to features overlying the internal target; and (d) a processor configured to remove information characteristic of the overlying features from the first set of data using the first and second sets of data to produce corrected information representing the internal target

    Systems and Methods for Correcting Optical Reflectance Measurements

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    We disclose measurement systems and methods for measuring analytes in target regions of samples that also include features overlying the target regions. The systems include: (a) a light source; (b) a detection system; (c) a set of at least first, second, and third light ports which transmit light from the light source to a sample and receive and direct light reflected from the sample to the detection system, generating a first set of data including information corresponding to both an internal target within the sample and features overlying the internal target, and a second set of data including information corresponding to features overlying the internal target; and (d) a processor configured to remove information characteristic of the overlying features from the first set of data using the first and second sets of data to produce corrected information representing the internal target

    Distribution Extensions of the Milliped Families Conotylidae and Rhiscosomididae (Diplopoda: Chordeumatida) into Northern Coastal British Columbia and Southern Alaska

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    Two samples of the chordeumatidan family Rhiscosomididae (Rhiscosomides mineri Silvestri, 1909) and 35 of the Conotylidae establish these taxa in the Alexander Archipelago and continental parts of the Alaskan Panhandle, USA, and northern coastal British Columbia (BC), Canada. Rhiscosomides mineri is also recorded from southwestern BC and, for the first time, from Washington State, USA. Two conotylids were recovered, a juvenile male of ?Bollmanella Chamberlin, 1941, and 3 males and 33 females of a possibly parthenogenetic form of Taiyutyla Chamberlin, 1952, conforming generally to T. shawi and T. lupus, both by Shear, 2004, on Vancouver Island. Diplopoda are predicted to inhabit the southern Yukon Territory

    Validation of a New NIRS Method for Measuring Muscle Oxygenation During Rhythmic Handgrip Exercise

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    Near infrared spectroscopy (NIRS) is commonly used to measure muscle oxygenation during exercise and recovery. Current NIRS algorithms do not account for variation in water content and optical pathlength during exercise. The current effort attempts to validate a newly developed NIRS algorithm during rhythmic handgrip exercise and recovery. Six female subjects, aver age 28 +/- 6 yrs, participated in the study. A venous catheter was placed in the retrograde direction in the antecubital space. A NIRS sensor with 30 mm source-detector separation was placed on the flexor digitorum profundus. Subjects performed two 5-min bouts of rhythmic handgrip exercise (2 s contraction/1 s relaxation) at 15% and 30% of maximal voluntary contraction. Venous blood was sampled before each bout, during the last minute of exercise, and after 5 minutes of recovery. Venous oxygen saturation (SvO2) was measured with a I-stat CG-4+ cartridge. Spectra were collected between 700-900 nm. A modified Beer's Law formula was used to calculate the absolute concentration of oxyhemoglobin (HbO2), deoxyhemoglobin (Hb) and water, as well as effective pathlength for each spectrum. Muscle oxygen saturation (SmO2) was calculated from the HbO2 and Hb results. The correlation between SvO2 and SmO2 was determined. Optical pathlength and water varied significantly during each exercise bout, with pathlength increasing approximately 20% and water increasing about 2%. R2 between blood and muscle SO2 was found to be 0.74, the figure shows the relationship over SvO2 values between 22% and 82%. The NIRS measurement was, on average, 6% lower than the blood measurement. It was concluded that pathlength changes during exercise because muscle contraction causes variation in optical scattering. Water concentration also changes, but only slightly. A new NIRS algorithm which accounts for exercise-induced variation in water and pathlength provided an accurate assessment of muscle oxygen saturation before, during and after exercise

    On the evolution of decoys in plant immune systems

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    The Guard-Guardee model for plant immunity describes how resistance proteins (guards) in host cells monitor host target proteins (guardees) that are manipulated by pathogen effector proteins. A recently suggested extension of this model includes decoys, which are duplicated copies of guardee proteins, and which have the sole function to attract the effector and, when modified by the effector, trigger the plant immune response. Here we present a proof-of-principle model for the functioning of decoys in plant immunity, quantitatively developing this experimentally-derived concept. Our model links the basic cellular chemistry to the outcomes of pathogen infection and resulting fitness costs for the host. In particular, the model allows identification of conditions under which it is optimal for decoys to act as triggers for the plant immune response, and of conditions under which it is optimal for decoys to act as sinks that bind the pathogen effectors but do not trigger an immune response.Comment: 15 pages, 6 figure

    Comparison of Interstitial Fluid pH, PCO2, PO2 with Venous Blood Values During Repetitive Handgrip Exercise

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    We evaluated the use of a small, fiber optic sensor to measure pH, PCO2 and PO2 from forearm muscle interstitial fluid (IF) during handgrip dynamometry. PURPOSE: Compare pH, PCO2 and PO2 values obtained from venous blood with those from the IF of the flexor digitorum superficialis (FDS) during three levels of exercise intensity. METHODS: Six subjects (5M/1F), average age 29+/-5 yrs, participated in the study. A venous catheter was placed in the retrograde direction in the antecubital space and a fiber optic sensor (Paratrend, Diametrics Medical, Inc.) was placed through a 22 G catheter into the FDS muscle under ultrasound guidance. After a 45 min rest period, subjects performed three 5-min bouts of repetitive handgrip exercise (2s contraction/1 s relaxation) at attempted levels of 15%, 30% and 45% of maximal voluntary contraction. The order of the exercise bouts was random with the second and third bouts started after blood lactate had returned to baseline. Venous blood was sampled every minute during exercise and analyzed with an I-Stat CG-4+ cartridge, while IF fiber optic sensor measurements were obtained every 2 s. Change from pre-exercise baseline to end of exercise was computed for pH, PCO2 and PO2. Blood and IF values were compared with a paired t-test. RESULTS: Baseline values for pH, PCO2 and PO2 were 7.37+/-0.02, 46+/-4 mm Hg, and 36+/-6 mm Hg respectively in blood and 7.39+/-0.02, 44+/-6 mm Hg, and 35+/-14 mm Hg in IF. Average changes over all exercise levels are noted in the Table below. For each parameter the exercise-induced change was at least twice as great in IF as in blood. In blood and IF, pH and PCO2 increases were directly related to exercise intensity. Change in venous PO2 was unrelated to exercise intensity, while IF PO2 decreased with increases in exercise intensity. CONCLUSIONS: Measurement of IF pH, PCO2 and PO2 is more sensitive to exercise intensity than measurement of the same parameters in venous blood and provides continuous assessment during and after exercise

    Assessment of the Effects of Acute and Repeated Exposure to Blast Overpressure in Rodents: Toward a Greater Understanding of Blast and the Potential Ramifications for Injury in Humans Exposed to Blast

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    Mild traumatic brain injury (mTBI) resulting from exposure to improvised explosive devices (IEDs) has fueled a requirement to develop animals models that mirror this condition using exposure to blast overpressure (BOP). En route to developing a model of repeated exposure to BOP we sought to initially characterize the effects of acute BOP exposure in rodents, focusing specifically on the levels of BOP exposure that produced clinical mTBI symptoms. We first measured BOP effects on gross motor function on a balance beam. Separate groups of unanesthetized rats were exposed (in different orientations) to 36.6, 74.5, and 116.7 kPa BOP exposure inside a pneumatically driven shock tube. Results demonstrated that rats exposed to 116.7 kPa demonstrated transient alterations or loss of consciousness indicated by a transient loss of righting and by increased latencies on the balance beam. The 116.7 kPa exposure was the threshold for overt pathology for acute BOP exposure with approximately 30% of rats presenting with evidence of subdural hemorrhage and cortical contusions. All animals exposed to 116.7 kPa BOP manifested evidence of significant pulmonary hemorrhage. Anterograde memory deficits were observed in rats exposed to 74.5 kPa facing the BOP wave and rats exposed to 116.7 kPa in the lateral (side) orientation. We next assessed repeated exposure to either lateral or frontal 36.6 kPa BOP in anesthetized rats, once per day for 12 days. Results showed that repeated exposure in the frontal, but not side, orientation to the BOP wave produced a transitory learning deficit on a Morris water maze task as shown by significantly longer latencies to reach the submerged platform in the second and third blocks of a four block session. Implications of these data are discussed in relation to the manifestation of mTBI in military personnel exposed to IEDs. Finally, we suggest that there are multiple types of long-term brain injury from blast exposure

    Recurrence and outcomes of Stevens-Johnson syndrome and toxic epidermal necrolysis in children

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    OBJECTIVES: To report clinical course, etiology, management, and long-term outcomes of children suffering from Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN). METHODS: We conducted a study of all pediatric patients with SJS or TEN admitted between 2000 and 2007 to the Hospital for Sick Children and Children's Hospital Boston, and particular attention was paid to clinical manifestations, etiology, mortality, and long-term outcomes. RESULTS: We identified 55 cases of SJS (n = 47), TEN (n = 5), or SJS/TEN overlap syndrome (n - 3). Drugs were identified as the most likely etiologic agent in 29 children (53%); antiepileptic drugs were the most common agents (n = 16), followed by sulfonamide antibiotics (n = 7) and chemotherapy drugs (n = 2). Acute Mycoplasma pneumoniae infection was confirmed in 12 children (22%), and herpes simplex virus was confirmed in 5 children (9%). Treatment regimens differed significantly between participating sites and included systemic antimicrobial agents (67%), systemic corticosteroids (40%), and antiviral drugs (31%). Intravenous immunoglobulin was administered to 21 children (38%), of whom 8 received concomitant systemic corticosteroids. Ten children (18%) had recurrence of SJS up to 7 years after the index episode, and 3 experienced multiple recurrences. Twenty-six children (47%) suffered long-term sequelae that mostly involved the skin and eyes. CONCLUSIONS: Mortality rate in children was lower than that reported in adults, but half of affected children suffered long-term complications. The recurrence rate of SJS was high (1 in 5), which suggests vulnerability and potential genetic predisposition. In the absence of standardized management guidelines for these conditions, treatment regimens differed significantly between participating institutions.Fil: Finkelstein, Yaron. University Of Toronto. Hospital For Sick Children; Canadá. University of Toronto; CanadáFil: Soon, Gordon S.. University Of Toronto. Hospital For Sick Children; Canadá. University of Toronto; CanadáFil: Acuna, Patrick. Children's Hospital Boston; Estados UnidosFil: George, Mathew. Children's Hospital Boston; Estados UnidosFil: Pope, Elena. University Of Toronto. Hospital For Sick Children; Canadá. University of Toronto; CanadáFil: Ito, Shinya. University Of Toronto. Hospital For Sick Children; Canadá. University of Toronto; CanadáFil: Shear, Neil H.. University of Toronto; Canadá. University Of Toronto. Hospital For Sick Children; CanadáFil: Koren, Gideon. University Of Toronto. Hospital For Sick Children; Canadá. University of Toronto; CanadáFil: Shannon, Michael W.. Children's Hospital Boston; Estados UnidosFil: Garcia Bournissen, Facundo. University of Toronto; Canadá. University Of Toronto. Hospital For Sick Children; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Ordinal-Level Phylogenomics of the Arthropod Class Diplopoda (Millipedes) Based on an Analysis of 221 Nuclear Protein-Coding Loci Generated Using Next-Generation Sequence Analyses

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    Background The ancient and diverse, yet understudied arthropod class Diplopoda, the millipedes, has a muddled taxonomic history. Despite having a cosmopolitan distribution and a number of unique and interesting characteristics, the group has received relatively little attention; interest in millipede systematics is low compared to taxa of comparable diversity. The existing classification of the group comprises 16 orders. Past attempts to reconstruct millipede phylogenies have suffered from a paucity of characters and included too few taxa to confidently resolve relationships and make formal nomenclatural changes. Herein, we reconstruct an ordinal-level phylogeny for the class Diplopoda using the largest character set ever assembled for the group. Methods Transcriptomic sequences were obtained from exemplar taxa representing much of the diversity of millipede orders using second-generation (i.e., next-generation or high-throughput) sequencing. These data were subject to rigorous orthology selection and phylogenetic dataset optimization and then used to reconstruct phylogenies employing Bayesian inference and maximum likelihood optimality criteria. Ancestral reconstructions of sperm transfer appendage development (gonopods), presence of lateral defense secretion pores (ozopores), and presence of spinnerets were considered. The timings of major millipede lineage divergence points were estimated. Results The resulting phylogeny differed from the existing classifications in a number of fundamental ways. Our phylogeny includes a grouping that has never been described (Juliformia+Merocheta+Stemmiulida), and the ancestral reconstructions suggest caution with respect to using spinnerets as a unifying characteristic for the Nematophora. Our results are shown to have significantly stronger support than previous hypotheses given our data. Our efforts represent the first step toward obtaining a well-supported and robust phylogeny of the Diplopoda that can be used to answer many questions concerning the evolution of this ancient and diverse animal group
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