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1.
Environ Entomol ; 52(6): 1033-1041, 2023 Dec 15.
Article in English | MEDLINE | ID: mdl-37793030

ABSTRACT

Due to the increased frequency of human-tick encounters and expanding ranges of ticks in the United States, there is a critical need to identify environmental conditions associated with tick populations and their likelihood to contact human hosts. In a passive tick surveillance partnership with the US Department of Agriculture Forest Inventory and Analysis (FIA) program, we identified environmental variables associated with tick encounters by forestry personnel. Ticks were identified by species and life stage, and site-specific variables were associated with each tick using FIA forest inventory datasets and generalized linear models with negative binomial distributions. Of the 55 FIA variables available, we identified biotic and abiotic environmental variables associated with Amblyomma americanum L. (carbon in litter material and standing dead tree aboveground dry biomass), Dermacentor variabilis Say (seedling species unevenness and elevation), and Ixodes scapularis L. (carbon in dead woody material and seedling species unevenness). We propose conducting future treatment-control studies using these forestry-related environmental variables to test their ability to alter tick abundance at sites. Land management decisions not only affect common flora and fauna, but changes to these habitats can also alter the way ticks parasitize hosts and use vegetation to find those hosts. These results can be used with land management decisions to prevent future human-tick encounters and highlight risk areas.


Subject(s)
Ixodes , Humans , United States , Animals , Southeastern United States , Ecosystem , Forests , Carbon
2.
Plant Biol (Stuttg) ; 24(7): 1108-1119, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36169609

ABSTRACT

European forests are an important source for timber production, human welfare, income, protection and biodiversity. During the last two decades, Europe has experienced a number of droughts which have been exceptional within the last 500 years, both in terms of duration and intensity. These droughts seem to leave remarkable imprints on the mortality dynamics of European forests. However, systematic observations on tree decline, with emphasis on a single species, has been scarce so far so that our understanding of mortality dynamics and drought occurrence is still limited at a continental scale. Here, we make use of the ICP Forest crown defoliation dataset, permitting us to retrospectively monitor tree mortality for all major conifers, major broadleaves, as well as a pooled dataset of minor tree species in Europe. In total, we analysed more than three million observations gathered during the last 25 years and employed a high-resolution drought index which can assess soil moisture anomaly based on a hydrological water-balance and runoff model. We found overall and species-specific increasing trends in mortality rates, accompanied by decreasing soil moisture. A generalized linear mixed model identified a previous-year soil moisture anomaly as the most important driver of mortality patterns in conifers, but the response was not uniform across the numerous analysed plots. We conclude that mortality patterns in European forests are currently reaching a concerning upward trend which could be further accelerated by global change-type droughts in the near future.


Subject(s)
Forests , Trees , Humans , Retrospective Studies , Trees/physiology , Droughts , Soil , Climate Change
3.
J Med Entomol ; 58(4): 1970-1972, 2021 07 16.
Article in English | MEDLINE | ID: mdl-33837420

ABSTRACT

Haemaphysalis longicornis Neumann, Asian longhorned tick, was collected in Madison County, Kentucky, United States as part of an ongoing collaborative-tick surveillance project. This is the first collection of this invasive tick that includes ancillary data on habitat and landscape features derived from the USDA Forest Service, Forest Inventory and Analysis program.


Subject(s)
Animal Distribution , Ecosystem , Ixodidae , Animals , Epidemiological Monitoring , Kentucky
4.
Clim Change ; 162(3): 1161-1176, 2020.
Article in English | MEDLINE | ID: mdl-33071396

ABSTRACT

Virtually all climate monitoring and forecasting efforts concentrate on hazards rather than on impacts, while the latter are a priority for planning emergency activities and for the evaluation of mitigation strategies. Effective disaster risk management strategies need to consider the prevailing "human terrain" to predict who is at risk and how communities will be affected. There has been little effort to align the spatiotemporal granularity of socioeconomic assessments with the granularity of weather or climate monitoring. The lack of a high-resolution socioeconomic baseline leaves methodical approaches like machine learning virtually untapped for pattern recognition of extreme climate impacts on livelihood conditions. While the request for "better" socioeconomic data is not new, we highlight the need to collect and analyze environmental and socioeconomic data together and discuss novel strategies for coordinated data collection via mobile technologies from a drought risk management perspective. A better temporal, spatial, and contextual understanding of socioeconomic impacts of extreme climate conditions will help to establish complex causal pathways and quantitative proof about climate-attributable livelihood impacts. Such considerations are particularly important in the context of the latest big data-driven initiatives, such as the World Bank's Famine Action Mechanism (FAM).

5.
ACS Appl Mater Interfaces ; 12(9): 11155-11162, 2020 Mar 04.
Article in English | MEDLINE | ID: mdl-32049480

ABSTRACT

Capabilities of highly sensitive surface-enhanced infrared absorption (SEIRA) spectroscopy are demonstrated by exploiting large-area templates (cm2) based on self-organized (SO) nanorod antennas. We engineered highly dense arrays of gold nanorod antennas featuring polarization-sensitive localized plasmon resonances, tunable over a broadband near- and mid-infrared (IR) spectrum, in overlap with the so-called "functional group" window. We demonstrate polarization-sensitive SEIRA activity, homogeneous over macroscopic areas and stable in time, by exploiting prototype self-assembled monolayers of IR-active octadecanthiol (ODT) molecules. The strong coupling between the plasmonic excitation and molecular stretching modes gives rise to characteristic Fano resonances in SEIRA. The SO engineering of the active hotspots in the arrays allows us to achieve signal amplitude improved up to 5.7%. This figure is competitive to the response of lithographic nanoantennas and is stable when the optical excitation spot varies from the micro- to macroscale, thus enabling highly sensitive SEIRA spectroscopy with cost-effective nanosensor devices.

6.
Int J Appl Earth Obs Geoinf ; 80: 1-12, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31885527

ABSTRACT

The temporal consistency of the fAPAR GEOV2 full time series (constituted by data derived from SPOT-VGT1/2 and PROBA-V) is analyzed against the single-sensor MODIS dataset, with a particular focus on the most recent fAPAR anomalies (z-scores) produced from PROBA-V in the period 2014-2017. The intercomparison highlights a systematic overestimation of GEOV2 fAPAR z-scores when compared to MODIS fAPAR, likely related to the observed positive bias (over 90% of the domain) in the PROBA-V vs. SPOT-VGT1/2 relationship. A simple two-step harmonization procedure has been proposed to remove this discrepancy, based on two separate linear corrections of SPOT-VGT1/2 (2001-2013) and PROBA-V (2014-2017) data with respect to MODIS, followed by a time lag correction. The harmonized GEOV2 time series preserves the overall dynamic of fAPAR, while removing the sensor bias and improving the consistency with MODIS data. The fAPAR anomalies from the harmonized GEOV2 time series provide unbiased estimates of z-scores that are overall well correlated (R = 0.55 ± 0.25) with the MODIS fAPAR anomalies.

7.
J Med Entomol ; 56(5): 1411-1419, 2019 09 03.
Article in English | MEDLINE | ID: mdl-31049584

ABSTRACT

Tick surveillance provides essential information on distributions and encounter frequencies; it is a component of operational activities in public health practice. Our research objectives were a proof-of-concept for collaborative surveillance, which involved establishing an academic and government partnership to enhance tick surveillance efforts. The University of Tennessee (UT) collaborated with United States Department of Agriculture Forest Service, Southern Research Station Forest Inventory Analysis (FIA) in an Occupational Health and Safety partnership. UT provided FIA crews in the southeastern United States with vials containing 80% ethanol (July 2014-November 2017). Crew members were instructed to put all encountered ticks into the vials and return them to FIA headquarters. UT identified all submitted ticks to species and life stage, and screened Amblyomma americanum (L.) for Ehrlichia bacteria using a nested-PCR assay. From the 198 returned vials, 1,180 ticks were submitted, including A. americanum (90.51%; 202 larvae, 503 nymphs, and 363 adults), Dermacentor variabilis Say (7.12%; 1 nymph, 83 adults), Ixodes scapularis (Say) (1.61%; 19 adults), Amblyomma maculatum Koch (0.59%; 1 nymph, 6 adults), and Amblyomma cajennense (Fabricius) (0.17%; 1 nymph, 1 adult). FIA crews encountered A. americanum with Ehrlichia and collection information was used to generate baseline occurrence data of tick encounters. Results indicate that this collaborative-tick surveillance can be improved and used to generate useful data including pathogen detection, and because crews revisit these sites, changes in tick encounters can be monitored.


Subject(s)
Animal Distribution , Epidemiological Monitoring , Ixodidae/microbiology , Ixodidae/physiology , Public-Private Sector Partnerships , Animals , Appalachian Region , Ehrlichia/isolation & purification , Female , Ixodidae/growth & development , Larva/microbiology , Larva/physiology , Male , Nymph/microbiology , Nymph/physiology , Seasons , Southeastern United States , Specimen Handling , Texas
8.
Acta Neuropathol Commun ; 5(1): 42, 2017 06 02.
Article in English | MEDLINE | ID: mdl-28578681

ABSTRACT

Bioactive lipids contribute to the pathophysiology of multiple sclerosis. Here, we show that lysophosphatidic acids (LPAs) are dysregulated in multiple sclerosis (MS) and are functionally relevant in this disease. LPAs and autotaxin, the major enzyme producing extracellular LPAs, were analyzed in serum and cerebrospinal fluid in a cross-sectional population of MS patients and were compared with respective data from mice in the experimental autoimmune encephalomyelitis (EAE) model, spontaneous EAE in TCR1640 mice, and EAE in Lpar2 -/- mice. Serum LPAs were reduced in MS and EAE whereas spinal cord LPAs in TCR1640 mice increased during the 'symptom-free' intervals, i.e. on resolution of inflammation during recovery hence possibly pointing to positive effects of brain LPAs during remyelination as suggested in previous studies. Peripheral LPAs mildly re-raised during relapses but further dropped in refractory relapses. The peripheral loss led to a redistribution of immune cells from the spleen to the spinal cord, suggesting defects of lymphocyte homing. In support, LPAR2 positive T-cells were reduced in EAE and the disease was intensified in Lpar2 deficient mice. Further, treatment with an LPAR2 agonist reduced clinical signs of relapsing-remitting EAE suggesting that the LPAR2 agonist partially compensated the endogenous loss of LPAs and implicating LPA signaling as a novel treatment approach. Graphical summary of lysophosphatidic signaling in multiple sclerosis.


Subject(s)
Encephalomyelitis, Autoimmune, Experimental/metabolism , Lysophospholipids/metabolism , Multiple Sclerosis/metabolism , Adolescent , Adult , Animals , Biomarkers/metabolism , Cohort Studies , Cross-Sectional Studies , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Encephalomyelitis, Autoimmune, Experimental/pathology , Female , Humans , Immunologic Factors/pharmacology , Male , Mice, 129 Strain , Mice, Inbred C57BL , Mice, Transgenic , Middle Aged , Multiple Sclerosis/drug therapy , Multiple Sclerosis/pathology , Myelin-Oligodendrocyte Glycoprotein , Peptide Fragments , Receptors, Lysophosphatidic Acid/agonists , Receptors, Lysophosphatidic Acid/genetics , Receptors, Lysophosphatidic Acid/metabolism , Young Adult
9.
J Breath Res ; 11(2): 026008, 2017 06 12.
Article in English | MEDLINE | ID: mdl-28492183

ABSTRACT

Gastric emptying can be assessed by an oral administration of a 13C labeled substrate and its response in the expiratory release of the oxidation product [Formula: see text]. Impaired gut function, reflected, for example, in an intolerance against enteral nutrition may delay or discontinue gastric emptying, potentially leading to multiple peaks in the time profile of expiration. The resulting profile cannot be analyzed by the usual data evaluation that is based on a 'beta exponential' (BEX) function. We developed a new approach that better reflects the underlying physiology. It allows a flexible time profile of gastric release and considers a transient [Formula: see text] retention in different compartments as well as an incomplete recovery of [Formula: see text] in the expiration. Parameters that describe the distribution/retention kinetics cannot be determined based on the same breath data that were used to estimate emptying. To enable the determination of the kinetic parameters, they were constrained to match published data using a Bayesian statistical analysis. The applicability of the new model was compared with BEX for healthy subjects. BEX fails to explain the observed data and, compared to the new approach, overestimates the speed of emptying. Predictive accuracy under impaired gastric motility was explored using synthetic data. Only the new approach can reproduce a multiphase absorption profile. When routine benchtop equipment was used for measurements, then the rate-limiting step for precision in the estimate of emptying is the quality in the a priori estimate for kinetic parameters rather than precision in measurements. Only about 80% of the absorbed [Formula: see text] has to be released by expiration. With these features, the new approach promises to widen the applicability of breath tests for gastric emptying.


Subject(s)
Breath Tests/methods , Carbon Dioxide/analysis , Gastric Emptying/physiology , Stomach/physiopathology , Administration, Oral , Adult , Bayes Theorem , Carbon Isotopes , Computer Simulation , Exhalation , Female , Humans , Intestinal Absorption , Kinetics , Male , Middle Aged , Uncertainty
10.
J Phys Condens Matter ; 27(25): 256002, 2015 Jul 01.
Article in English | MEDLINE | ID: mdl-26043764

ABSTRACT

The magneto-transport properties of single proton-implanted ZnO and of Li(7%)-doped ZnO microwires have been studied. The as-grown microwires were highly insulating and not magnetic. After proton implantation the Li(7%) doped ZnO microwires showed a non-monotonous behavior of the negative magneto-resistance (MR) at temperature above 150 K. This is in contrast to the monotonous NMR observed below 50 K for proton-implanted ZnO. The observed difference in the transport properties of the wires is related to the amount of stable Zn vacancies created at the near surface region by the proton implantation and Li doping. The magnetic field dependence of the resistance might be explained by the formation of a magnetic/non-magnetic heterostructure in the wire after proton implantation.

11.
Phys Rev Lett ; 114(20): 204801, 2015 May 22.
Article in English | MEDLINE | ID: mdl-26047232

ABSTRACT

We report on high resolution measurements of resonances in the spectrum of coherent synchrotron radiation (CSR) at the Canadian Light Source (CLS). The resonances permeate the spectrum at wave number intervals of 0.074 cm(-1), and are highly stable under changes in the machine setup (energy, bucket filling pattern, CSR in bursting or continuous mode). Analogous resonances were predicted long ago in an idealized theory as eigenmodes of a smooth toroidal vacuum chamber driven by a bunched beam moving on a circular orbit. A corollary of peaks in the spectrum is the presence of pulses in the wakefield of the bunch at well-defined spatial intervals. Through experiments and further calculations we elucidate the resonance and wakefield mechanisms in the CLS vacuum chamber, which has a fluted form much different from a smooth torus. The wakefield is observed directly in the 30-110 GHz range by rf diodes, and indirectly by an interferometer in the THz range. The wake pulse sequence found by diodes is less regular than in the toroidal model, and depends on the point of observation, but is accounted for in a simulation of fields in the fluted chamber. Attention is paid to polarization of the observed fields, and possible coherence of fields produced in adjacent bending magnets. Low frequency wakefield production appears to be mainly local in a single bend, but multibend effects cannot be excluded entirely, and could play a role in high frequency resonances. New simulation techniques have been developed, which should be invaluable in further work.

12.
HNO ; 63(5): 373-5, 2015 May.
Article in German | MEDLINE | ID: mdl-24292222

ABSTRACT

We report on a 19-year-old patient who developed negative pressure pulmonary edema (NPPE) with respiratory insufficiency following abscess tonsillectomy. NPPE is an unpredictable and life-threatening postoperative complication characterized by respiratory insufficiency. It may arise immediately after extubation or later in the postoperative period. NPPE is frequently observed after laryngospasm or in combination with space-occupying lesions in the pharynx and larynx. Treatment comprises the immediate correction of hypoxemia, preferably by noninvasive respiratory support using continuous positive airway pressure (CPAP), although in some cases reintubation is necessary.


Subject(s)
Continuous Positive Airway Pressure , Peritonsillar Abscess/complications , Peritonsillar Abscess/surgery , Pulmonary Edema/etiology , Pulmonary Edema/therapy , Tonsillectomy/adverse effects , Humans , Male , Pulmonary Edema/diagnosis , Treatment Outcome , Young Adult
13.
Eur J Clin Nutr ; 68(9): 1067-71, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25052228

ABSTRACT

BACKGROUND/OBJECTIVES: The short chain fatty acid acetate (AC), may have a role in increasing insulin sensitivity, thus lowering risk for obesity and type 2 diabetes mellitus. It is unclear if AC kinetics is similar in normal (NI) and hyperinsulinaemic (HI) participants. Therefore, we studied AC absorption from the distal colon in participants with normal (<40 pmol/l) and high (≥40 pmol/l) plasma insulin. This work was a part of a series of studies conceived to compute a kinetic model for AC. Kinetic parameters such as estimates of rate of entry into peripheral blood, hepatic uptake and endogenous/exogenous production were compared in the groups. SUBJECTS/METHODS: Overnight fasted NI (n=9) and HI (n=8) participants were given rectal infusions containing sodium AC (90 mmol/l). The solutions were retained for 40 min, then voided for AC measurement. Total amount of AC infused was 27 mmols. RESULTS: AC absorption from the distal colon (279±103 vs 322±91 µmol/min, P=0.76) and hepatic uptake of AC (155±101 vs 146±85 µmol/min, P=0.94) were similar in the groups. Endogenous and exogenous AC production was significantly higher in NI than HI participants. Plasma AC was inversely proportional to plasma insulin concentrations in the entire cohort (y=k/x, where k=1813). CONCLUSIONS: There was low power to detect differences in AC absorption rate and hepatic AC uptake in NI vs HI. The rate of entry of AC into peripheral blood was similar in NI and HI participants. However, hyperinsulinaemia may alter endogenous and exogenous AC metabolism.


Subject(s)
Acetates/metabolism , Colon/metabolism , Hyperinsulinism/metabolism , Insulin/blood , Intestinal Absorption , Liver/metabolism , Acetates/blood , Acetates/pharmacokinetics , Adult , Female , Humans , Insulin Resistance , Male , Reference Values
14.
Nitric Oxide ; 41: 79-84, 2014 Sep 15.
Article in English | MEDLINE | ID: mdl-24963794

ABSTRACT

Our aim was to study the ability of an immortalized cell line (AMJ2-C11) to sustain aerobic cell respiration at decreasing oxygen concentrations under continuous sulfide exposure. We assumed that the rate of elimination of sulfide through the pathway linked to the mitochondrial respiratory chain and therefore operating under aerobic conditions, should decrease with limiting oxygen concentrations. Thus, sulfide's inhibition of cellular respiration would occur faster under continuous sulfide exposure when the oxygen concentration is in the very low range. The experiments were performed with an O2K-oxygraph (Oroboros Instruments) by suspending 0.5-1×10(6) cells in 2 ml of continuously stirred respiration medium at 37 °C and calculating the oxygen flux (JO2) as the negative derivative of the oxygen concentration in the medium. The cells were studied in two different metabolic states, namely under normal physiologic respiration (1) and after uncoupling of mitochondrial respiration (2). Oxygen concentration was controlled by means of a titration-injection pump, resulting in average concentration values of 0.73±0.05 µM, 3.1±0.2 µM, and 6.2±0.2 µM. Simultaneously we injected a 2 mM Na2S solution at a continuous rate of 10 µl/s in order to quantify the titration-time required to reduce the JO2 to 50% of the initial respiratory activity. Under the lowest oxygen concentration this effect was achieved after 3.5 [0.3;3.5] and 11.7 [6.2;21.2]min in the uncoupled and coupled state, respectively. This time was statistically significantly shorter when compared to the intermediate and the highest O2 concentrations tested, which yielded values of 24.6 [15.5;28.1]min (coupled) and 35.9 [27.4;59.2]min (uncoupled), as well as 42.4 [27.5;42.4]min (coupled) and 51.5 [46.4;51.7]min (uncoupled). All data are medians [25%, and 75% percentiles]. Our results confirm that the onset of inhibition of cell respiration by sulfide occurs earlier under a continuous exposure when approaching the anoxic condition. This property may contribute to the physiological role of sulfide as an oxygen sensor.


Subject(s)
Cell Hypoxia/physiology , Oxygen/metabolism , Sulfides/metabolism , Animals , Cell Line , Cell Respiration/physiology , Mice , Mitochondria/metabolism , Quinone Reductases
16.
Eur J Clin Nutr ; 66(9): 1029-34, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22828730

ABSTRACT

BACKGROUND/OBJECTIVES: Colonic fermentation of dietary fiber may improve insulin sensitivity by the metabolic effects of short chain fatty acids (SCFA) in reducing free fatty acids (FFA). The main objectives of this study were to compare peripheral uptake of acetate (AC) in participants with normal (<40 pmol/l, NI) and high (≥ 40 pmol/l, HI) plasma insulin, and the ability of AC to reduce FFA in both the groups. SUBJECTS/METHODS: Overnight fasted NI (n=9) and HI (n=9) participants were given an intravenous (IV) infusion of 140 mmol/l sodium acetate at three different rates over 90 min. The total amount of AC infused was 51.85 mmols. RESULTS: AC clearance in NI participants was not significantly different than that in HI participants (2.11 ± 0.23 vs 2.09 ± 0.24 ml/min). FFA fell in both the groups, but rebounded to a greater extent in NI than HI participants (time × group interaction, P=0.001). Significant correlations between insulin resistance (IR) indices (homeostasis model assessment of insulin resistance (HOMA-IR), Matsuda and insulinogenic index) vs FFA rebound during IV AC infusion were also observed. CONCLUSIONS: These findings suggest that AC uptake is similar in both the groups. Participants with lower plasma insulin and lower IR indices had a greater FFA rebound. These results support the hypothesis that increasing AC concentrations in the systemic circulation may reduce lipolysis and plasma FFA concentrations and thus improve insulin sensitivity. More in-depth studies are needed to look at the effects of SCFA on FFA metabolism in insulin-resistant participants.


Subject(s)
Acetates/administration & dosage , Blood Glucose/metabolism , Fatty Acids, Nonesterified/metabolism , Hyperinsulinism/drug therapy , Hyperinsulinism/metabolism , Insulin/metabolism , Adolescent , Adult , Aged , Fatty Acids, Nonesterified/blood , Female , Glucose Tolerance Test , Humans , Hyperinsulinism/blood , Insulin/blood , Insulin Resistance , Linear Models , Male , Middle Aged , Young Adult
17.
Eur Surg Res ; 48(4): 194-9, 2012.
Article in English | MEDLINE | ID: mdl-22678054

ABSTRACT

BACKGROUND: Anastomotic leakage after esophageal surgery is a significant cause of morbidity and mortality. Postoperative leakage of esophagogastric anastomosis has been reported in 2-30% of surgical patient, resulting in an increased need for reoperation and a high risk of subsequent esophageal stricture formation and fistula. So far, experimental investigations on major factors influencing the healing of esophageal anastomoses, e.g. neovascularization and collagen deposition, have been hindered by the lack of a functional rodent model. METHODS: We developed a novel technique of gastric tube formation followed by end-to-end esophagogastric anastomosis in a rat model. Standardized anastomoses were carried out in 18 Brown-Norway rats and normal esophagogastric healing was studied by measuring anastomotic breaking strength 5 days after surgery. RESULTS: Five animals showed an insufficiency of the esophagogastric anastomosis as determined by anastomotic leakage testing. Normal anastomotic healing was found in 10 animals. The anastomotic breaking strength was 1.93 ± 0.45 N. CONCLUSION: The rat model for performing esophagogastric anastomoses after gastric tube formation may serve as a functional and useful model in future research studies on microvascular and molecular processes of anastomotic healing.


Subject(s)
Anastomosis, Surgical , Esophagus/surgery , Stomach/surgery , Wound Healing , Anastomosis, Surgical/adverse effects , Anastomosis, Surgical/methods , Animals , Male , Models, Animal , Rats , Rats, Inbred BN
18.
Article in English | MEDLINE | ID: mdl-23366292

ABSTRACT

After an amputation, processes of change in the body image as well as a change in body scheme have direct influences on the quality of living in every patient. Within this paper, a paradigm of experimental induced body illusion (the Rubber Hand Illusion, RHI) is integrated in a prosthetic hardware simulator concept. This concept combines biodynamical and visual feedback to enhance the quality of rehabilitation and to integrate patients' needs into the development of prostheses aiming on user-centered solutions. Therefore, user-centered design parameters are deducted. Furthermore, the basic concept of the visual simulation is presented and a possibility for its implementation is given. Finally, issues and conclusions for future work are described.


Subject(s)
Computer Simulation , Feedback, Sensory , Orthotic Devices , Prosthesis Design , Body Image , Humans
19.
Article in English | MEDLINE | ID: mdl-23366849

ABSTRACT

In this paper, a novel biomechanical modeling and simulation environment with an emphasis on user-specific customization is presented. A modular modeling approach for multi-body systems allows a flexible extension by specific biomechanical modeling elements and enables an efficient application in dynamic simulation and optimization problems. A functional distribution of model description and model parameter data in combination with standardized interfaces enables a simple and reliable replacement or modification of specific functional components. The user-specific customization comprises the identification of anthropometric model parameters as well as the generation of a virtual three-dimensional character. The modeling and simulation environment is associated with Prosthesis-User-in-the-Loop, a hardware simulator concept for the design and optimization of lower limb prosthetic devices based on user experience and assessment. For a demonstration of the flexibility and capability of the modeling and simulation environment, an exemplary application in context of the hardware simulator is given.


Subject(s)
Artificial Limbs , Feedback, Physiological/physiology , Gait/physiology , Leg/physiology , Models, Biological , Posture/physiology , Computer Simulation , Female , Humans , Male , Prosthesis Fitting/methods , Young Adult
20.
Eur J Clin Nutr ; 65(12): 1279-86, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21712835

ABSTRACT

BACKGROUND/OBJECTIVES: Colonic fermentation of dietary fibre produces short-chain fatty acids (SCFAs), acetate, propionate and butyrate, which may protect against type 2 diabetes by reducing serum free-fatty acids (FFAs). Since hyperinsulinaemia is associated with insulin resistance and increased diabetes risk, the main objective was to compare markers of colonic fermentation after acute inulin ingestion in subjects with normal (<40 pmol/l, NI) and high (≥40 pmol/l, HI) plasma insulin. SUBJECTS/METHODS: Overnight fasted NI (n=9) and HI (n=9) subjects were studied for 4 h on two separate days after consuming 300 ml drinks containing 75 g glucose (Glucose) or 75 g glucose plus 24 g inulin (Inulin) using a randomized, single-blind, crossover design. RESULTS: Inulin elicited a higher breath hydrogen and methane areas under the curve (AUC), but the increases in SCFA responses were not statistically significant. Mean serum-acetate concentration over the 4-h study period was higher in NI than in HI subjects (44.3 ± 6.9 vs 22.5 ± 3.7 µmol/l, P=0.001). The rate of rebound of FFA was reduced by Inulin, with FFA at 4 h being less after Inulin than Glucose, regardless of insulin status (0.310 ± 0.028 vs 0.432 ± 0.042 mEq/l, P=0.008). CONCLUSIONS: This suggests that inulin increases short-term markers for colonic fermentation, but a longer study period may be necessary to observe differences in SCFA production. The reason for the lower serum acetate in HI is unclear but may be due to reduced absorption, increased clearance or decreased endogenous production. This suggests the need to compare acetate kinetics in normal and hyperinsulinaemic subjects.


Subject(s)
Colon/drug effects , Dietary Carbohydrates/pharmacology , Dietary Fiber/metabolism , Fatty Acids, Volatile/metabolism , Hyperinsulinism/metabolism , Inulin/pharmacology , Acetates/blood , Adult , Area Under Curve , Biomarkers/metabolism , Breath Tests , Colon/metabolism , Cross-Over Studies , Female , Fermentation , Glucose/metabolism , Humans , Hydrogen/metabolism , Male , Methane/metabolism , Single-Blind Method
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