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  1. Article ; Online: Enhanced motor learning and motor savings after acute intermittent hypoxia are associated with a reduction in metabolic cost.

    Bogard, Alysha T / Hemmerle, Makenna R / Smith, Andrew C / Tan, Andrew Q

    The Journal of physiology

    2023  

    Abstract: Breathing mild bouts of low oxygen air (i.e. acute intermittent hypoxia, AIH) has been shown to improve locomotor function in humans after a spinal cord injury. How AIH-induced gains in motor performance are achieved remains unclear. We examined the ... ...

    Abstract Breathing mild bouts of low oxygen air (i.e. acute intermittent hypoxia, AIH) has been shown to improve locomotor function in humans after a spinal cord injury. How AIH-induced gains in motor performance are achieved remains unclear. We examined the hypothesis that AIH augments motor learning and motor retention during a locomotor adaptation task. We further hypothesized that gains in motor learning and retention will be associated with reductions in net metabolic power, consistent with the acquisition of energetically favourable mechanics. Thirty healthy individuals were randomly allocated into either a control group or an AIH group. We utilized a split-belt treadmill to characterize adaptations to an unexpected belt speed perturbation of equal magnitude during an initial exposure and a second exposure. Adaptation was characterized by changes in spatiotemporal step asymmetry, anterior-posterior force asymmetry, and net metabolic power. While both groups adapted by reducing spatial asymmetry, only the AIH group achieved significant reductions in double support time asymmetry and propulsive force asymmetry during both the initial and the second exposures to the belt speed perturbation. Net metabolic power was also significantly lower in the AIH group, with significant reductions from the initial perturbation exposure to the second. These results provide the first evidence that AIH mediates improvements in both motor learning and retention. Further, our results suggest that reductions in net metabolic power continue to be optimized upon subsequent learning and are driven by more energetically favourable temporal coordination strategies. Our observation that AIH facilitates motor learning and retention can be leveraged to design rehabilitation interventions that promote functional recovery. KEY POINTS: Brief exposures to low oxygen air, known as acute intermittent hypoxia (AIH), improves locomotor function in humans after a spinal cord injury, but it remains unclear how gains in motor performance are achieved. In this study, we tested the hypothesis that AIH induces enhancements in motor learning and retention by quantifying changes in interlimb coordination, anterior-posterior force symmetry and metabolic cost during a locomotor adaptation task. We show the first evidence that AIH improves both motor learning and savings of newly learned temporal interlimb coordination strategies and force asymmetry compared to untreated individuals. We further demonstrate that AIH elicits greater reductions in metabolic cost during motor learning that continues to be optimized upon subsequent learning. Our findings suggest that AIH-induced gains in locomotor performance are facilitated by enhancements in motor learning and retention of more energetically favourable coordination strategies.
    Language English
    Publishing date 2023-11-20
    Publishing country England
    Document type Journal Article
    ZDB-ID 3115-x
    ISSN 1469-7793 ; 0022-3751
    ISSN (online) 1469-7793
    ISSN 0022-3751
    DOI 10.1113/JP285425
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  2. Article ; Online: Impact of Gravel Pits on Water Quality in Alluvial Aquifers

    Karlović, Igor / Marković, Tamara / Smith, Andrew C. / Maldini, Krešimir

    Hydrology. 2023 Apr. 21, v. 10, no. 4

    2023  

    Abstract: Gravel pits are considered potentially hazardous in terms of groundwater quality protection as they represent an open part of the aquifer system, increasing the aquifer’s vulnerability to contamination from the surface. The aim of this research was to ... ...

    Abstract Gravel pits are considered potentially hazardous in terms of groundwater quality protection as they represent an open part of the aquifer system, increasing the aquifer’s vulnerability to contamination from the surface. The aim of this research was to determine the biogeochemical processes in gravel pits that have a positive effect on the groundwater quality in the alluvial aquifer in NW Croatia. The aquifer is situated below developed agricultural land, with high groundwater nitrate concentrations having been recorded over the last decades. The differences between two gravel pits and the surrounding groundwater were studied using in situ, hydrochemical, and isotopic parameters (δ¹⁵N-NO₃ and δ¹⁸O-NO₃), together with existing microbial data. The analyses of nitrogen species indicated that nitrate attenuation processes take place in gravel pits. Bacterial denitrification and nitrate uptake by algae were responsible for significant decreases in nitrate concentration. These processes were more effective in the inactive gravel pit, which has a longer water residence time and during warm periods, when microbial biomass, abundance, and activity were high. The seasonally variable microbial activity also affected trace metals, removing them from groundwater, possibly through the biosorption of metal ions. The presented research shows that the observed biogeochemical processes are associated with seasonal changes that affect the types and number of microbial communities and the chemical composition of water, resulting in gravel pits being groundwater remediation points.
    Keywords agricultural land ; alluvial aquifer ; biosorption ; chemical composition ; denitrification ; gravel ; gravel pits ; groundwater ; hydrochemistry ; microbial activity ; microbial biomass ; nitrates ; nitrogen ; remediation ; water quality ; Croatia
    Language English
    Dates of publication 2023-0421
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article ; Online
    ZDB-ID 2777964-6
    ISSN 2306-5338
    ISSN 2306-5338
    DOI 10.3390/hydrology10040099
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  3. Article: Peak Slope Ratio of the Recruitment Curves Compared to Muscle Evoked Potentials to Optimize Standing Configurations with Percutaneous Epidural Stimulation after Spinal Cord Injury.

    Alazzam, Ahmad M / Ballance, William B / Smith, Andrew C / Rejc, Enrico / Weber, Kenneth A / Trainer, Robert / Gorgey, Ashraf S

    Journal of clinical medicine

    2024  Volume 13, Issue 5

    Abstract: Background: ...

    Abstract Background:
    Language English
    Publishing date 2024-02-27
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2662592-1
    ISSN 2077-0383
    ISSN 2077-0383
    DOI 10.3390/jcm13051344
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  4. Article: Tracking the nitrogen cycle in a vulnerable alluvial system using a multi proxy approach: Case study Varaždin alluvial aquifer, Croatia

    Marković, Tamara / Karlović, Igor / Orlić, Sandi / Kajan, Katarina / Smith, Andrew C.

    Science of the total environment. 2022 Dec. 20, v. 853

    2022  

    Abstract: At high concentrations nitrate is considered a serious environmental pollutant which degrades the quality of ground and surface waters. Such high nitrate concentrations (>50 mg NO₃/L) have been observed for decades in the alluvial aquifer in the Varaždin ...

    Abstract At high concentrations nitrate is considered a serious environmental pollutant which degrades the quality of ground and surface waters. Such high nitrate concentrations (>50 mg NO₃/L) have been observed for decades in the alluvial aquifer in the Varaždin region of Croatia. Here we employ a novel cross disciplinary approach (dual isotopes, chemical, bacteria diversity and mixing modelling) to determine sources of nitrate and processes that can influence nitrate concentration within this vulnerable alluvial aquifer. Ten groundwater wells were sampled across the region and in different hydrological conditions for basic chemical, stable isotopes (δ¹⁸O-H₂O, δ²H-H₂O, δ¹⁵N-NO₃ and δ¹⁸O-NO₃), and bacterial diversity analyses. In addition, solid samples, i.e. soil samples and fertilizers were collected and analysed for bulk δ¹⁵N. The primary nitrate sources were manure, sewage, soil organic N, and ammonia fertilizers, however we observe no clear evidence to indicate that synthetic fertilizers are a major contributor to groundwater nitrate concentrations. Whilst denitrification was observed in the parts of the study area with dissolved oxygen (DO) deficiency, i.e. anoxic conditions, nitrification has been identified as the major process responsible for nitrate behaviour within the aquifer system. Our results will facilitate the creation of a conceptual model of nitrate behaviour in the study area and from this, a numerical groundwater nitrate transport model. These data, understanding of nitrate dynamics and subsequent models will be critical for future sustainable water and agricultural management of the study area.
    Keywords agricultural management ; alluvial aquifer ; ammonia ; case studies ; denitrification ; dissolved oxygen ; environment ; groundwater ; models ; nitrates ; nitrification ; nitrogen cycle ; pollutants ; sewage ; soil organic nitrogen ; Croatia
    Language English
    Dates of publication 2022-1220
    Publishing place Elsevier B.V.
    Document type Article
    ZDB-ID 121506-1
    ISSN 1879-1026 ; 0048-9697
    ISSN (online) 1879-1026
    ISSN 0048-9697
    DOI 10.1016/j.scitotenv.2022.158632
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  5. Article ; Online: Scent Marks Signal Species, Sex, and Reproductive Status in Tamarins (Saguinus spp., Neotropical Primates).

    Poirier, Alice C / Waterhouse, John S / Dunn, Jacob C / Smith, Andrew C

    Chemical senses

    2021  Volume 46

    Abstract: Olfactory communication is an important mediator of social interactions in mammals, thought to provide information about an individual's identity and current social, reproductive, and health status. In comparison with other taxa such as carnivores and ... ...

    Abstract Olfactory communication is an important mediator of social interactions in mammals, thought to provide information about an individual's identity and current social, reproductive, and health status. In comparison with other taxa such as carnivores and rodents, few studies have examined primate olfactory communication. Tamarins (Callitrichidae) conspicuously deposit odorous secretions, produced by specialized scent glands, in their environment. In this study, we combined behavioral and chemical data on captive cotton-top tamarins, Saguinus oedipus, and bearded emperor tamarins, S. imperator subgrisescens, to examine the role of olfactory communication in the advertisement of species, sex, and reproductive status. We observed no difference in scent-marking behavior between species; however, females marked more frequently than males, and reproductive individuals more than non-reproductive ones. In addition, tamarins predominantly used their anogenital gland when scent-marking, followed by the suprapubic gland. We collected swabs of naturally deposited tamarin anogenital scent marks, and analyzed these samples using headspace gas chromatography-mass spectrometry. Despite a limited sample size, we established differences in tamarin anogenital mark chemical composition between species, sex and reproductive status, and identified 41 compounds. The compounds identified, many of which have been reported in previous work on mammalian semiochemistry, form targets for future bioassay studies to identify semiochemicals. Our non-invasive method for collecting deposited scent marks makes it a promising method for the study of olfactory communication in scent-marking animal species, applicable to field settings and for the study of elusive animals.
    MeSH term(s) Animal Communication ; Animals ; Saguinus ; Scent Glands/physiology ; Sex Factors ; Sexual Behavior, Animal/physiology ; Smell/physiology
    Language English
    Publishing date 2021-03-11
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 754122-3
    ISSN 1464-3553 ; 0379-864X
    ISSN (online) 1464-3553
    ISSN 0379-864X
    DOI 10.1093/chemse/bjab008
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  6. Article ; Online: Transcutaneous Electrical Spinal Cord Stimulation to Promote Recovery in Chronic Spinal Cord Injury.

    Tefertiller, Candace / Rozwod, Meghan / VandeGriend, Eric / Bartelt, Patricia / Sevigny, Mitch / Smith, Andrew C

    Frontiers in rehabilitation sciences

    2022  Volume 2

    Abstract: Objective: To evaluate the impact of using transcutaneous electrical spinal cord stimulation (TSCS) on upper and lower extremity function in individuals with chronic spinal cord injury (SCI).: Design: Prospective case series.: Setting: SCI ... ...

    Abstract Objective: To evaluate the impact of using transcutaneous electrical spinal cord stimulation (TSCS) on upper and lower extremity function in individuals with chronic spinal cord injury (SCI).
    Design: Prospective case series.
    Setting: SCI specific rehabilitation hospital.
    Participants: A convenience sample (
    Interventions: Individuals participated in 60 min of upper extremity (UE) functional task-specific practice (FTP) in combination with TSCS and 60 min of locomotor training in combination with TSCS 5x/week.
    Main outcome measures: The primary outcome for this analysis was the Capabilities of Upper Extremity Test (CUE-T). Secondary outcomes include UE motor score (UEMS), LE motor score (LEMS), sensation (light touch and pin prick), Nine-Hole Peg Test, 10 meter walk test, 6 min walk test, and 5 min stand test.
    Results: Seven individuals (four motor complete; three motor incomplete) completed 20-80 sessions UE and LE training augmented with TSCS and without any serious adverse events. Improvements were reported on the CUE-T in all seven individuals. Two individuals improved their ASIA impairment scale (AIS) classification (B to C; C to D) and two individuals improved their neurologic level of injury by one level (C4-C5; C5-C6). Sensation improved in five individuals and all four who started out with motor complete SCIs were able to voluntarily activate their LEs on command in the presence of stimulation.
    Conclusion: Individuals with chronic SCI who had previously demonstrated a plateau in function after an intensive outpatient therapy program were able to improve in a variety of UE and LE outcomes in response to TSCS without any adverse events. This was a small pilot study and future fully powered studies with comparative interventions need to be completed to assess efficacy.
    Language English
    Publishing date 2022-01-04
    Publishing country Switzerland
    Document type Journal Article
    ISSN 2673-6861
    ISSN (online) 2673-6861
    DOI 10.3389/fresc.2021.740307
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  7. Article ; Online: Tracking the nitrogen cycle in a vulnerable alluvial system using a multi proxy approach: Case study Varaždin alluvial aquifer, Croatia.

    Marković, Tamara / Karlović, Igor / Orlić, Sandi / Kajan, Katarina / Smith, Andrew C

    The Science of the total environment

    2022  Volume 853, Page(s) 158632

    Abstract: At high concentrations nitrate is considered a serious environmental pollutant which degrades the quality of ground and surface waters. Such high nitrate concentrations (>50 mg ... ...

    Abstract At high concentrations nitrate is considered a serious environmental pollutant which degrades the quality of ground and surface waters. Such high nitrate concentrations (>50 mg NO
    MeSH term(s) Nitrates/analysis ; Fertilizers/analysis ; Sewage/analysis ; Manure/analysis ; Environmental Monitoring/methods ; Ammonia/analysis ; Croatia ; Water Pollutants, Chemical/analysis ; Nitrogen Isotopes/analysis ; Groundwater ; Nitrification ; Soil ; Water/analysis ; Oxygen/analysis ; China
    Chemical Substances Nitrates ; Fertilizers ; Sewage ; Manure ; Ammonia (7664-41-7) ; Water Pollutants, Chemical ; Nitrogen Isotopes ; Soil ; Water (059QF0KO0R) ; Oxygen (S88TT14065)
    Language English
    Publishing date 2022-09-07
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 121506-1
    ISSN 1879-1026 ; 0048-9697
    ISSN (online) 1879-1026
    ISSN 0048-9697
    DOI 10.1016/j.scitotenv.2022.158632
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  8. Article ; Online: Predicting Outdoor Walking 1 Year After Spinal Cord Injury: A Retrospective, Multisite External Validation Study.

    Draganich, Christina / Weber, Kenneth A / Thornton, Wesley A / Berliner, Jeffrey C / Sevigny, Mitch / Charlifue, Susan / Tefertiller, Candace / Smith, Andrew C

    Journal of neurologic physical therapy : JNPT

    2023  Volume 47, Issue 3, Page(s) 155–161

    Abstract: Background and purpose: Predicting future outdoor walking ability after spinal cord injury (SCI) is important, as this is associated with community engagement and social participation. A clinical prediction rule (CPR) was derived for predicting outdoor ... ...

    Abstract Background and purpose: Predicting future outdoor walking ability after spinal cord injury (SCI) is important, as this is associated with community engagement and social participation. A clinical prediction rule (CPR) was derived for predicting outdoor walking 1 year after SCI. While promising, this CPR has not been validated, which is necessary to establish its clinical value. The objective of this study was to externally validate the CPR using a multisite dataset.
    Methods: This was a retrospective analysis of US SCI Model Systems data from 12 centers. L3 motor score, L5 motor score, and S1 sensory score were used as predictor variables. The dataset was split into testing and training datasets. The testing dataset was used as a holdout dataset to provide an unbiased estimate of prediction performance. The training dataset was used to determine the optimal CPR threshold through a "leave-one-site-out" cross-validation framework. The primary outcome was self-reported outdoor walking ability 1 year after SCI.
    Results: A total of 3721 participants' data were included. Using the optimal CPR threshold (CPR ≥ 33 threshold value), we were able to predict outdoor walking 1 year with high cross-validated accuracy and prediction performance. For the entire dataset, area under receiver operator characteristic curve was 0.900 (95% confidence interval: 0.890-0.910; P < 0.0001).
    Discussion and conclusions: The outdoor walking CPR has been externally validated. Future research should conduct a clinical outcomes and cost-benefit impact analysis for implementing this CPR. Our results support that clinicians may use this 3-variable CPR for prediction of future outdoor walking ability.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A411 ).
    MeSH term(s) Humans ; Retrospective Studies ; Walking ; Spinal Cord Injuries/complications
    Language English
    Publishing date 2023-01-10
    Publishing country United States
    Document type Video-Audio Media ; Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2276921-3
    ISSN 1557-0584 ; 1557-0576 ; 1085-049X
    ISSN (online) 1557-0584
    ISSN 1557-0576 ; 1085-049X
    DOI 10.1097/NPT.0000000000000428
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  9. Article ; Online: Response to Letter to the Editor on "A Single Dermatome Clinical Prediction Rule for Independent Walking One Year After Spinal Cord Injury".

    Smith, Andrew C / Draganich, Christina / Thornton, Wesley A / Berliner, Jeffrey C / Lennarson, Peter J / Rejc, Enrico / Sevigny, Mitch / Charlifue, Susan / Tefertiller, Candace / Weber, Kenneth A

    Archives of physical medicine and rehabilitation

    2024  

    Language English
    Publishing date 2024-04-04
    Publishing country United States
    Document type Letter
    ZDB-ID 80057-0
    ISSN 1532-821X ; 0003-9993
    ISSN (online) 1532-821X
    ISSN 0003-9993
    DOI 10.1016/j.apmr.2024.04.002
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  10. Article: A review of phosphate oxygen isotope values in global bedrocks: Characterising a critical endmember to the soil phosphorus system

    Smith, Andrew C / Pfahler, Verena / Tamburini, Federica / Blackwell, Martin S. A / Granger, Steven J

    Journal of plant nutrition and soil science. 2021 Feb., v. 184, no. 1

    2021  

    Abstract: Understanding the phosphate oxygen isotope (δ¹⁸O‐PO₄) composition of bedrock phosphate sources is becoming ever more important, especially in areas of soil research which use this isotope signature as a proxy for biological cycling of phosphorus (P). For ...

    Abstract Understanding the phosphate oxygen isotope (δ¹⁸O‐PO₄) composition of bedrock phosphate sources is becoming ever more important, especially in areas of soil research which use this isotope signature as a proxy for biological cycling of phosphorus (P). For many of these studies, obtaining a sample of the source bedrock or applied mineral fertiliser for isotope analysis is impossible; meaning there is now a demand for a comprehensive characterisation of global bedrock δ¹⁸O‐PO₄ to support this work. Here we compile δ¹⁸O‐PO₄ data from a wide range of global bedrocks, including 56 new values produced as part of this study and a comprehensive overview of those within the previously existing literature. We present δ¹⁸O‐PO₄ data from the range of major phosphatic lithologies alongside as much metadata for the samples as could be gathered. Much of the data comes from bedrocks of marine sedimentary origin (< 1 Ma = > +22‰, > 540 Ma = ≈ +12‰), but we also present data from bedrocks associated with guano (range: +19.5 to +15‰) and igneous deposits (range: +12 to –0.8‰), both of which have distinct δ¹⁸O‐PO₄ signatures due to their formation mechanisms. We show that where repeat measurements of the same formation have been undertaken, regardless of method or exact sample location, there is an average within formation error of ± 1.25‰. This is important, as is constitutes a reasonable level of uncertainty for phosphorus cycling studies which need to estimate bedrock δ¹⁸O‐PO₄ composition based on the literature. In combination, this data set presents 284 δ¹⁸O‐PO₄ values from 56 countries; a comprehensive starting point for researchers interested in understanding bedrock end member δ¹⁸O‐PO₄.
    Keywords animal manures ; bedrock ; data collection ; lithology ; metadata ; mineral fertilizers ; oxygen isotopes ; phosphates ; phosphorus ; plant nutrition ; soil ; uncertainty
    Language English
    Dates of publication 2021-02
    Size p. 25-34.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note NAL-AP-2-clean ; REVIEW
    ISSN 1436-8730
    DOI 10.1002/jpln.202000513
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