Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 593
Filter
1.
Pulmonology ; 29(5): 399-409, 2023.
Article in English | MEDLINE | ID: mdl-37045743

ABSTRACT

RATIONALE: The six-minute walk test (6MWT) is a practical and simple field-based test to assess physical capacity. Several reference equations for six-minute walking distance (6MWD, m) exist, but have a number of limitations that decrease their clinical utility. In addition, no reference equations exist for the 6MWT-derived outcome six-minute walk work (6MWORK, kg.m). OBJECTIVES: To establish new reference equations for 6MWD and 6MWORK on a 20 m course using data from the population-based Canadian Cohort Obstructive Lung Disease study. METHODS AND MEASUREMENTS: A total of 335 participants without obstructive or restrictive pulmonary function, with normal self-reported health status, normal exercise capacity, and <30 pack years cigarette smoking history were selected to create a representative sample of Canadian adults aged ≥40 years. All participants performed two 6MWTs. Reference equations were derived using multiple regression analyses. MAIN RESULTS: On average, 6MWD and 6MWORK were 541±98 m and 41.3 ± 11.2 kg.m, respectively. All outcomes were significantly greater in males than females. Sex-specific reference equations were derived from the results of 6MWD and 6MWORK with an explained variance of 24 to 35%. CONCLUSIONS: This study established reference equations for 6MWD and 6MWORK on a 20 m course in Caucasian males and females aged ≥40 years with normal pulmonary function, self-reported health status and exercise capacity. These newly derived reference equations add value to the assessment of functional capacity in clinical practice.


Subject(s)
Lung , Walking , Male , Female , Humans , Adult , Reference Values , Canada/epidemiology , Walk Test
2.
J Dairy Sci ; 105(8): 6880-6894, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35773031

ABSTRACT

The measurement of pH in the reticulorumen in combination with a time-pH threshold has been widely applied in research to diagnose subacute ruminal acidosis. However, other pH metrics also have biological value. In this study, 44 animals were monitored during the transition period using reticuloruminal pH boluses. Traditional and more complex pH characteristics were calculated to characterize the reticuloruminal pH profile: time pH <6, slope of a logistic cumulative pH curve (ß0), and deviations [squared error (SqEr)] from pH predictions based on a harmonic static model. In this study, we aimed to examine the associations between those pH metrics and metabolic health parameters, feed intake, and activity. Finally, to describe the reticuloruminal pH dynamically, we also constructed a dynamic linear model. The results of this model were studied in relation to feed intake. All pH parameters were mutually correlated (particularly ß0 and SqEr; mean Pearson correlation of -0.52). pH patterns, rather than time pH <6, were associated with metabolic health and feed intake: high variation in daily pH (ß0 parameter) was reflected in higher blood concentrations of nonesterified fatty acids. Moreover, pH deviations of the harmonic model were negatively associated with feed intake and rumination behavior. This research confirms the biological importance of pH metrics focusing on pH variation and pH deviations and provides deeper insight into its associations with metabolic health status, feed intake, and activity during early lactation.


Subject(s)
Milk , Rumen , Animal Feed/analysis , Animals , Benchmarking , Cattle , Diet/veterinary , Eating , Female , Hydrogen-Ion Concentration , Lactation , Milk/chemistry , Rumen/metabolism
3.
J Dent Res ; 101(9): 1025-1033, 2022 08.
Article in English | MEDLINE | ID: mdl-35416080

ABSTRACT

Head and neck cancer (HNC) affects over 890,000 people annually worldwide and has a mortality rate of 50%. Aside from poor survival, HNC pain impairs eating, drinking, and talking in patients, severely reducing quality of life. Different pain phenotype in patients (allodynia, hyperalgesia, and spontaneous pain) results from a combination of anatomical, histopathological, and molecular differences between cancers. Poor pathologic features (e.g., perineural invasion, lymph node metastasis) are associated with increased pain. The use of syngeneic/immunocompetent animal models, as well as a new mouse model of perineural invasion, provides novel insights into the pathobiology of HNC pain. Glial and immune modulation of the tumor microenvironment affect not only cancer progression but also pain signaling. For example, Schwann cells promote cancer cell proliferation, migration, and secretion of nociceptive mediators, whereas neutrophils are implicated in sex differences in pain in animal models of HNC. Emerging evidence supports the existence of a functional loop of cross-activation between the tumor microenvironment and peripheral nerves, mediated by a molecular exchange of bioactive contents (pronociceptive and protumorigenic) via paracrine and autocrine signaling. Brain-derived neurotrophic factor, tumor necrosis factor α, legumain, cathepsin S, and A disintegrin and metalloprotease 17 expressed in the HNC microenvironment have recently been shown to promote HNC pain, further highlighting the importance of proinflammatory cytokines, neurotrophic factors, and proteases in mediating HNC-associated pain. Pronociceptive mediators, together with nerve injury, cause nociceptor hypersensitivity. Oncogenic, pronociceptive mediators packaged in cancer cell-derived exosomes also induce nociception in mice. In addition to increased production of pronociceptive mediators, HNC is accompanied by a dampened endogenous antinociception system (e.g., downregulation of resolvins and µ-opioid receptor expression). Resolvin treatment or gene delivery of µ-opioid receptors provides pain relief in preclinical HNC models. Collectively, recent studies suggest that pain and HNC progression share converging mechanisms that can be targeted for cancer treatment and pain management.


Subject(s)
Head and Neck Neoplasms , Quality of Life , Animals , Cell Proliferation , Female , Head and Neck Neoplasms/complications , Humans , Hyperalgesia , Male , Mice , Neuroglia , Pain , Tumor Microenvironment
4.
BJOG ; 129(5): 708-721, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34559946

ABSTRACT

OBJECTIVE: We aimed to explore: (i) the association of sedentary time (ST) and physical activity (PA) during pregnancy with the placental expression of genes related to glucose and lipid metabolism in pregnant women who are obese; (ii) maternal metabolic factors mediating changes in these placental transcripts; and (iii) cord blood markers related to the mRNAs mediating neonatal adiposity. DESIGN: Multicentre randomised controlled trial. SETTING: Hospitals in nine European countries. POPULATION: A cohort of 112 pregnant women with placental tissue. METHODS: Both ST and moderate-to-vigorous PA (MVPA) levels were measured objectively using accelerometry at three time periods during pregnancy. MAIN OUTCOME MEASURES: Placental mRNAs (FATP2, FATP3, FABP4, GLUT1 and PPAR-γ) were measured with NanoString technology. Maternal and fetal metabolic markers and neonatal adiposity were assessed. RESULTS: Longer periods of ST, especially in early to middle pregnancy, was associated with lower placental FATP2 and FATP3 expression (P < 0.05), whereas MVPA at baseline was inversely associated with GLUT1 mRNA (P = 0.02). Although placental FATP2 and FATP3 expression were regulated by the insulin-glucose axis (P < 0.05), no maternal metabolic marker mediated the association of ST/MVPA with placental mRNAs (P > 0.05). Additionally, placental FATP2 expression was inversely associated with cord blood triglycerides and free fatty acids (FFAs; P < 0.01). No cord blood marker mediated neonatal adiposity except for cord blood leptin, which mediated the effects of PPAR-γ on neonatal sum of skinfolds (P < 0.05). CONCLUSIONS: In early to middle pregnancy, ST is associated with the expression of placental genes linked to lipid transport. PA is hardly related to transporter mRNAs. Strategies aimed at reducing sedentary behaviour during pregnancy could modulate placental gene expression, which may help to prevent unfavourable fetal and maternal pregnancy outcomes. TWEETABLE ABSTRACT: Reducing sedentary behaviour in pregnancy might modulate placental expression of genes related to lipid metabolism in women who are obese.


Subject(s)
Glucose , Sedentary Behavior , Exercise , Female , Humans , Infant, Newborn , Life Style , Lipid Metabolism/genetics , Obesity/complications , Placenta/metabolism , Pregnancy , Pregnancy Outcome , Pregnant Women , RNA, Messenger
5.
Heliyon ; 8(12): e12556, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36619438

ABSTRACT

Cyberbullying is defined as aggression intending to inflict harm on others by electronic communication technologies. Cyberbullying has become more common as social media has grown and is accompanied by negative mental health consequences. Research on cyberbullying and mental health in adolescents suggests cyberbullying victimization moderates the relationship between social comparison and social anxiety, but little is known about this phenomenon in college students. Therefore, the objective of this study was to explore the relationship between cyberbullying, social anxiety, and social comparison amongst college students. A convenience sample of 486 undergraduate students from southern Texas and northern Ohio completed a PyschData survey that assessed social anxiety, social comparison, experiences with be a cyberbullying victim, perpetrator, or both. We found that social anxiety was associated with cyberbullying victimization and perpetration; however, social comparison was not. Cyberbullying victimization was not a moderator between social comparison and anxiety, suggesting that unlike adolescence, college students' experiences with these constructs may be unique to their developmental level.

6.
Clin Exp Dermatol ; 47(2): 343-350, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34388289

ABSTRACT

BACKGROUND: Lichen sclerosus (LS) affects the female anogenital area, causing anatomical changes. Reported symptoms include itching, soreness and dyspareunia. AIM: To evaluate the quality of life and sexual functioning in women with LS. METHODS: In total, 158 women aged over 18 years, diagnosed with LS, and referred to North Denmark Regional Hospital from January 2018 to November 2019, were included. Three questionnaires, the Female Sexual Function Index (FSFI), Dermatology Life Quality Index (DLQI) and the World Health Organization Five-Item Well-Being Index (WHO-5), were completed. RESULTS: The women (mean age 47 years, range 18-76) presented a low score on all FSFI scales, with a mean score of 13.83 (95% CI 12.46-15.20), indicating reduced sexual functioning. The subgroup evaluation scored for desire 2.32, arousal 2.23, lubrication 2.39, orgasm 2.28, satisfaction 3.02 and pain 1.59. The DLQI results revealed a mean score of 7.88 (95% CI 7.02-8.74), indicating a moderate effect on the women's everyday life. The mean subscores were treatment 0.32, sexual difficulties 1.56, relations 1.02, work/study 0.34, sport 0.45, social activities 0.54, clothing 0.89, shopping 0.22, embarrassment 0.99 and itching, soreness and pain 1.55. The mean score for the WHO-5 was 56.66 (95% CI 53.48-59.84) indicating that 40% of the women had signs of depression. CONCLUSION: LS has a considerable influence on the sexual functioning and quality of life of women. Healthcare professionals must not only consider the biological aspects but also the psychological and social aspects.


Subject(s)
Lichen Sclerosus et Atrophicus , Quality of Life , Sexual Behavior , Sexual Dysfunction, Physiological/etiology , Adolescent , Adult , Aged , Analysis of Variance , Cross-Sectional Studies , Female , Humans , Lichen Sclerosus et Atrophicus/complications , Lichen Sclerosus et Atrophicus/psychology , Middle Aged , Sexual Dysfunction, Physiological/epidemiology
8.
IUCrJ ; 8(Pt 5): 719-731, 2021 Sep 01.
Article in English | MEDLINE | ID: mdl-34584734

ABSTRACT

Laboratory X-ray diffraction contrast tomography (LabDCT) is a novel imaging technique for non-destructive 3D characterization of grain structures. An accurate grain reconstruction critically relies on precise segmentation of diffraction spots in the LabDCT images. The conventional method utilizing various filters generally satisfies segmentation of sharp spots in the images, thereby serving as a standard routine, but it also very often leads to over or under segmentation of spots, especially those with low signal-to-noise ratios and/or small sizes. The standard routine also requires a fine tuning of the filtering parameters. To overcome these challenges, a deep learning neural network is presented to efficiently and accurately clean the background noise, thereby easing the spot segmentation. The deep learning network is first trained with input images, synthesized using a forward simulation model for LabDCT in combination with a generic approach to extract features of experimental backgrounds. Then, the network is applied to remove the background noise from experimental images measured under different geometrical conditions for different samples. Comparisons of both processed images and grain reconstructions show that the deep learning method outperforms the standard routine, demonstrating significantly better grain mapping.

9.
IUCrJ ; 8(Pt 4): 559-573, 2021 Jul 01.
Article in English | MEDLINE | ID: mdl-34258005

ABSTRACT

Laboratory diffraction contrast tomography (LabDCT) is a novel technique for non-destructive imaging of the grain structure within polycrystalline samples. To further broaden the use of this technique to a wider range of materials, both the spatial resolution and detection limit achieved in the commonly used Laue focusing geometry have to be improved. In this work, the possibility of improving both grain indexing and shape reconstruction was investigated by increasing the sample-to-detector distance to facilitate geometrical magnification of diffraction spots in the LabDCT projections. LabDCT grain reconstructions of a fully recrystallized iron sample, obtained in the conventional Laue focusing geometry and in a magnified geometry, are compared to one characterized by synchrotron X-ray diffraction contrast tomography, with the latter serving as the ground truth. It is shown that grain indexing can be significantly improved in the magnified geometry. It is also found that the magnified geometry improves the spatial resolution and the accuracy of the reconstructed grain shapes. The improvement is shown to be more evident for grains smaller than 40 µm than for larger grains. The underlying reasons are clarified by comparing spot features for different LabDCT datasets using a forward simulation tool.

10.
J Dairy Sci ; 104(10): 10449-10461, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34304870

ABSTRACT

Sensor technologies for mastitis detection have resulted in the collection and availability of a large amount of data. As a result, scientific publications reporting mastitis detection research have become less driven by approaches based on biological assumptions and more by data-driven modeling. Most of these approaches try to predict mastitis events from (combinations of) raw sensor data to which a wide variety of methods are applied originating from machine learning and classical statistical approaches. However, an even wider variety in terminologies is used by researchers for methods that are similar in nature. This makes it difficult for readers from other disciplines to understand the specific methods that are used and how these differ from each other. The aim of this paper was to provide a framework (filtering, transformation, and classification) for describing the different methods applied in sensor data-based clinical mastitis detection research and use this framework to review and categorize the approaches and underlying methods described in the scientific literature on mastitis detection. We identified 40 scientific publications between 1992 and 2020 that applied methods to detect clinical mastitis from sensor data. Based on these publications, we developed and used the framework and categorized these scientific publications into the 2 data processing techniques of filtering and transformation. These data processing techniques make raw data more amendable to be used for the third step in our framework, that of classification, which is used to distinguish between healthy and nonhealthy (mastitis) cows. Most publications (n = 34) used filtering or transformation, or a combination of these 2, for data processing before classification, whereas the remaining publications (n = 6) classified the observations directly from raw data. Concerning classification, applying a simple threshold was the most used method (n = 19 publications). Our work identified that within approaches several different methods and terminologies for similar methods were used. Not all publications provided a clear description of the method used, and therefore it seemed that different methods were used between publications, whereas in fact just a different terminology was used, or the other way around. This paper is intended to serve as a reference for people from various research disciplines who need to collaborate and communicate efficiently about the topic of sensor-based mastitis detection and the methods used in this context. The framework used in this paper can support future research to correctly classify approaches and methods, which can improve the understanding of scientific publication. We encourage future research on sensor-based animal disease detection, including that of mastitis detection, to use a more coherent terminology for methods, and clearly state which technique (e.g., filtering) and approach (e.g., moving average) are used. This paper, therefore, can serve as a starting point and further stimulates the interdisciplinary cooperation in sensor-based mastitis research.


Subject(s)
Cattle Diseases , Mastitis , Animals , Cattle , Female , Language , Machine Learning , Mastitis/veterinary
11.
Dig Dis Sci ; 66(10): 3495-3504, 2021 10.
Article in English | MEDLINE | ID: mdl-33128681

ABSTRACT

BACKGROUND: Dieulafoy's lesion (DL) is a rare but increasingly recognized cause of severe upper GI hemorrhage (SUGIH). There is little consensus regarding the endoscopic approach to management of bleeding from DL. AIMS: Our purposes were to compare 30-day outcomes of patients with SUGIH from DL with Doppler endoscopic probe (DEP) monitoring of blood flow and guided treatment versus standard visually guided hemostasis (VG). METHODS: Eighty-two consecutive DL patients with SUGIH were identified in a large CURE Hemostasis database from previous prospective cohort studies and two recent RCTs at two university-based medical centers. 30-day outcomes including rebleeding, surgery, angiography, death, and severe medical complications were compared between the two treatment groups. RESULTS: 40.2% of DL bleeds occurred in inpatients. 43.9% of patients had cardiovascular disease, and 48.7% were taking medications associated with bleeding. For the entire cohort, 41.3% (26/63) of patients treated with VG had a composite 30-day outcome as compared to 10.5% (2/19) of patients treated with DEP (p = 0.017). Rebleeding occurred within 30 days in 33.3% and 10.5% of those treated with VG and DEP, respectively (p = 0.051). After propensity score matching, the adjusted 30-day composite outcome occurred in 39.0% in the VG group compared to 2.6% in the DEP group (p < 0.001). Adjusted 30-day rebleeding occurred in 25.3% in the VG group versus 2.6% in the DEP group (p < 0.001). DISCUSSION: DL patients with SUGIH were frequently inpatients and had severe cardiovascular comorbidities and recurrent bleeding. Lesion arterial blood flow monitoring and obliteration are an effective way to treat bleeding from DL which reduces negative 30-day clinical outcomes.


Subject(s)
Arterial Pressure , Arteries/abnormalities , Gastrointestinal Hemorrhage/etiology , Gastrointestinal Tract/blood supply , Adult , Aged , Aged, 80 and over , Endoscopy, Digestive System , Female , Gastrointestinal Hemorrhage/diagnosis , Gastrointestinal Hemorrhage/therapy , Humans , Male , Middle Aged , Monitoring, Physiologic , Treatment Outcome , Young Adult
12.
Neuroscience ; 468: 247-264, 2021 08 01.
Article in English | MEDLINE | ID: mdl-33246068

ABSTRACT

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease preferentially affecting motoneurones. Transgenic mouse models have been used to investigate the role of abnormal motoneurone excitability in this disease. Whilst an increased excitability has repeatedly been demonstrated in vitro in neonatal and embryonic preparations from SOD1 mouse models, the results from the only studies to record in vivo from spinal motoneurones in adult SOD1 models have produced conflicting findings. Deficits in repetitive firing have been reported in G93A SOD1(high copy number) mice but not in presymptomatic G127X SOD1 mice despite shorter motoneurone axon initial segments (AISs) in these mice. These discrepancies may be due to the earlier disease onset and prolonged disease progression in G93A SOD1 mice with recordings potentially performed at a later sub-clinical stage of the disease in this mouse. To test this, and to explore how the evolution of excitability changes with symptom onset we performed in vivo intracellular recording and AIS labelling in G127X SOD1 mice immediately after symptom onset. No reductions in repetitive firing were observed showing that this is not a common feature across all ALS models. Immunohistochemistry for the Na+ channel Nav1.6 showed that motoneurone AISs increase in length in G127X SOD1 mice at symptom onset. Consistent with this, the rate of rise of AIS components of antidromic action potentials were significantly faster confirming that this increase in length represents an increase in AIS Na+ channels occurring at symptom onset in this model.


Subject(s)
Amyotrophic Lateral Sclerosis , Axon Initial Segment , Neurodegenerative Diseases , Amyotrophic Lateral Sclerosis/genetics , Animals , Disease Models, Animal , Mice , Mice, Transgenic , Spinal Cord , Superoxide Dismutase/genetics , Superoxide Dismutase-1/genetics
13.
Diabet Med ; 38(2): e14413, 2021 02.
Article in English | MEDLINE | ID: mdl-32991758

ABSTRACT

AIMS: To describe the metabolic phenotypes of early gestational diabetes mellitus and their association with adverse pregnancy outcomes. METHODS: We performed a post hoc analysis using data from the Vitamin D And Lifestyle Intervention for gestational diabetes prevention (DALI) trial conducted across nine European countries (2012-2014). In women with a BMI ≥29 kg/m2 , insulin resistance and secretion were estimated from the oral glucose tolerance test values performed before 20 weeks, using homeostatic model assessment of insulin resistance and Stumvoll first-phase indices, respectively. Women with early gestational diabetes, defined by the International Association of Diabetes and Pregnancy Study Groups criteria, were classified into three groups: GDM-R (above-median insulin resistance alone), GDM-S (below-median insulin secretion alone), and GDM-B (combination of both) and the few remaining women were excluded. RESULTS: Compared with women in the normal glucose tolerance group (n = 651), women in the GDM-R group (n = 143) had higher fasting and post-load glucose values and insulin levels, with a greater risk of having large-for-gestational age babies [adjusted odds ratio 3.30 (95% CI 1.50-7.50)] and caesarean section [adjusted odds ratio 2.30 (95% CI 1.20-4.40)]. Women in the GDM-S (n = 37) and GDM-B (n = 56) groups had comparable pregnancy outcomes with those in the normal glucose tolerance group. CONCLUSIONS: In overweight and obese women with early gestational diabetes, higher degree of insulin resistance alone was more likely to be associated with adverse pregnancy outcomes than lower insulin secretion alone or a combination of both.


Subject(s)
Blood Glucose/metabolism , Cesarean Section/statistics & numerical data , Diabetes, Gestational/epidemiology , Diabetes, Gestational/metabolism , Fetal Macrosomia/epidemiology , Gestational Age , Insulin/metabolism , Obesity, Maternal/epidemiology , Adult , Female , Glucose Tolerance Test , Humans , Insulin Resistance , Insulin Secretion , Phenotype , Pregnancy
14.
Acta Crystallogr A Found Adv ; 76(Pt 6): 652-663, 2020 Nov 01.
Article in English | MEDLINE | ID: mdl-33125349

ABSTRACT

Laboratory X-ray diffraction contrast tomography (LabDCT) has recently been developed as a powerful technique for non-destructive mapping of grain microstructures in bulk materials. As the grain reconstruction relies on segmentation of diffraction spots, it is essential to understand the physics of the diffraction process and resolve all the spot features in detail. To this aim, a flexible and standalone forward simulation model has been developed to compute the diffraction projections from polycrystalline samples with any crystal structure. The accuracy of the forward simulation model is demonstrated by good agreements in grain orientations, boundary positions and shapes between a virtual input structure and that reconstructed based on the forward simulated diffraction projections of the input structure. Further experimental verification is made by comparisons of diffraction spots between simulations and experiments for a partially recrystallized Al sample, where a satisfactory agreement is found for the spot positions, sizes and intensities. Finally, applications of this model to analyze specific spot features are presented.

15.
J Cosmet Laser Ther ; 22(2): 60-64, 2020 Feb 17.
Article in English | MEDLINE | ID: mdl-32041440

ABSTRACT

Treating diffuse facial redness with an intense pulsed light (IPL) source usually requires multiple sessions and may not achieve complete clearance. The 595 nm pulsed dye laser (PDL) enjoys a good reputation for reducing facial redness with non-purpuric settings. The objective of this study was to compare facial redness reduction using these two devices. After establishing the lowest light dose able to achieve transient purpura for the same pulse width of 1,5 ms with each technology, right and left sides of the face were randomly assigned for each type of treatment. There were two treatment sessions 4 weeks apart and the final evaluation was performed 8 weeks after thesecond treatment. Four blinded experienced dermatologists analyzed pre and post-treatment photographs, which demonstrated an average of 60% improvement on the segment treated with the IPL as opposed to 45% on the other segment. Pain level was described as mild and the procedure was well tolerated for both types of treatment. In this study we showed that short-pulsed intense pulsed light and PDL are similar in decreasing facial redness when non-purpuric low fluence settings are used. The IPL was faster and did not have consumables.


Subject(s)
Face/radiation effects , Intense Pulsed Light Therapy/methods , Lasers, Dye/therapeutic use , Low-Level Light Therapy/methods , Rosacea/radiotherapy , Cosmetic Techniques/adverse effects , Cosmetic Techniques/instrumentation , Female , Humans , Intense Pulsed Light Therapy/adverse effects , Lasers, Dye/adverse effects , Low-Level Light Therapy/adverse effects , Male , Middle Aged , Pain/etiology
16.
Sci Rep ; 10(1): 893, 2020 01 21.
Article in English | MEDLINE | ID: mdl-31964988

ABSTRACT

Intramuscular injections of botulinum toxin block pre-synaptic cholinergic release at neuromuscular junctions producing a temporary paralysis of affected motor units. There is increasing evidence, however, that the effects are not restricted to the periphery and can alter the central excitability of the motoneurones at the spinal level. This includes increases in input resistance, decreases in rheobase currents for action potentials and prolongations of the post-spike after-hyperpolarization. The aim of our experiments was to investigate possible anatomical explanations for these changes. Unilateral injections of Botulinum toxin A mixed with a tracer were made into the gastrocnemius muscle of adult rats and contralateral tracer only injections provided controls. Immunohistochemistry for Ankyrin G and the vesicular acetylcholine transporter labelled axon initial segments and cholinergic C-boutons on traced motoneurones at 2 weeks post-injection. Soma size was not affected by the toxin; however, axon initial segments were 5.1% longer and 13.6% further from the soma which could explain reductions in rheobase. Finally, there was a reduction in surface area (18.6%) and volume (12.8%) but not frequency of C-boutons on treated motoneurones potentially explaining prolongations of the after-hyperpolarization. Botulinum Toxin A therefore affects central anatomical structures controlling or modulating motoneurone excitability explaining previously observed excitability changes.


Subject(s)
Axon Initial Segment/drug effects , Botulinum Toxins, Type A/pharmacology , Motor Neurons/drug effects , Muscle, Skeletal/drug effects , Animals , Botulinum Toxins, Type A/administration & dosage , Cholera Toxin/administration & dosage , Cholinergic Neurons/drug effects , Injections, Intramuscular , Male , Motor Neurons/physiology , Muscle, Skeletal/cytology , Rats, Wistar , Spinal Cord/cytology , Vesicular Acetylcholine Transport Proteins/metabolism
17.
Physiol Behav ; 211: 112657, 2019 11 01.
Article in English | MEDLINE | ID: mdl-31445015

ABSTRACT

BACKGROUND: It has been hypothesized that resting state cardiac vagal activity (CVA) - an indicator of parasympathetic nervous system activity - is a specific psychophysiological marker of executive control function. Here, we propose an alternative hypothesis - that CVA is associated with early stage attention orientation, promoting the flexible uptake of new information, on which the later operation of such executive control functions depends. We therefore predicted that CVA would predict the interaction between orienting and executive control. This was tested using the revised version of the Attention Network Test (ANT-R) that was developed to distinguish between orienting and executive attention during a stimulus conflict task. METHODS: Healthy adults (N = 48) performed the ANT-R and their resting CVA was measured over a 5 min period using ECG recordings. RESULTS: Multiple regression analyses indicated that, when other factors were controlled for, CVA was more strongly associated with the interaction between the orienting and executive control terms than with either factor individually. CONCLUSION: Higher levels of CVA are specifically implicated in the modulation of executive control by intrinsic orientation operating at early stages of conflict detection. These initial findings of higher CVA on orienting attention in conflict detection need to be replicated in larger samples.


Subject(s)
Attention/physiology , Executive Function/physiology , Heart Rate/physiology , Orientation/physiology , Adult , Electrocardiography , Female , Humans , Male , Neuropsychological Tests , Parasympathetic Nervous System/physiology , Photic Stimulation , Reaction Time/physiology , Young Adult
18.
J Geophys Res Atmos ; 124(6): 2932-2945, 2019 Mar 27.
Article in English | MEDLINE | ID: mdl-31218150

ABSTRACT

Several recent studies from both Greenland and Antarctica have reported significant changes in the water isotopic composition of near-surface snow between precipitation events. These changes have been linked to isotopic exchange with atmospheric water vapor and sublimation-induced fractionation, but the processes are poorly constrained by observations. Understanding and quantifying these processes are crucial to both the interpretation of ice core climate proxies and the formulation of isotope-enabled general circulation models. Here, we present continuous measurements of the water isotopic composition in surface snow and atmospheric vapor together with near-surface atmospheric turbulence and snow-air latent and sensible heat fluxes, obtained at the East Greenland Ice-Core Project drilling site in summer 2016. For two 4-day-long time periods, significant diurnal variations in atmospheric water isotopologues are observed. A model is developed to explore the impact of this variability on the surface snow isotopic composition. Our model suggests that the snow isotopic composition in the upper subcentimeter of the snow exhibits a diurnal variation with amplitudes in δ18O and δD of ~2.5‰ and ~13‰, respectively. As comparison, such changes correspond to 10-20% of the magnitude of seasonal changes in interior Greenland snow pack isotopes and of the change across a glacial-interglacial transition. Importantly, our observation and model results suggest, that sublimation-induced fractionation needs to be included in simulations of exchanges between the vapor and the snow surface on diurnal timescales during summer cloud-free conditions in northeast Greenland.

19.
Phys Rev Lett ; 122(9): 091803, 2019 Mar 08.
Article in English | MEDLINE | ID: mdl-30932529

ABSTRACT

A search for mixing between active neutrinos and light sterile neutrinos has been performed by looking for muon neutrino disappearance in two detectors at baselines of 1.04 and 735 km, using a combined MINOS and MINOS+ exposure of 16.36×10^{20} protons on target. A simultaneous fit to the charged-current muon neutrino and neutral-current neutrino energy spectra in the two detectors yields no evidence for sterile neutrino mixing using a 3+1 model. The most stringent limit to date is set on the mixing parameter sin^{2}θ_{24} for most values of the sterile neutrino mass splitting Δm_{41}^{2}>10^{-4} eV^{2}.

20.
Nat Commun ; 10(1): 1106, 2019 03 07.
Article in English | MEDLINE | ID: mdl-30846688

ABSTRACT

Calcium carbonates (CaCO3) often accumulate in mangrove and seagrass sediments. As CaCO3 production emits CO2, there is concern that this may partially offset the role of Blue Carbon ecosystems as CO2 sinks through the burial of organic carbon (Corg). A global collection of data on inorganic carbon burial rates (Cinorg, 12% of CaCO3 mass) revealed global rates of 0.8 TgCinorg yr-1 and 15-62 TgCinorg yr-1 in mangrove and seagrass ecosystems, respectively. In seagrass, CaCO3 burial may correspond to an offset of 30% of the net CO2 sequestration. However, a mass balance assessment highlights that the Cinorg burial is mainly supported by inputs from adjacent ecosystems rather than by local calcification, and that Blue Carbon ecosystems are sites of net CaCO3 dissolution. Hence, CaCO3 burial in Blue Carbon ecosystems contribute to seabed elevation and therefore buffers sea-level rise, without undermining their role as CO2 sinks.

SELECTION OF CITATIONS
SEARCH DETAIL