The role of the primary motor cortex (M1) in volitional and reflexive pharyngeal swallowing.

Background and aims: The primary motor cortex (M1) controls voluntary motor behaviours. M1 has been identified to play a major role in the execution of voluntary corticospinal tasks as well as self-initiated corticobulbar tasks. However, the involvement of M1 in more complex corticubulbar tasks, such as swallowing, is not yet fully understood. Swallowing is quite different from other voluntary motor tasks as it has both voluntary and reflexive components. The degree of M1 involvement in the pharyngeal, or more reflexive, component of swallowing is unclear. Studies investigating the role of M1 in swallowing have yielded contradictory findings regarding the specific functional contribution of M1 to swallowing. Therefore, further investigation is warranted to clarify the role of M1 in pharyngeal swallowing. Discrete saliva or water swallowing has been utilized in most studies investigating neurophysiology of swallowing in health and disease. However, individuals most frequently complete multiple, consecutive swallows during the ingestion of liquid. Biomechanical differences between discrete and continuous water swallows have been identified using videofluoroscopic swallowing study (VFSS). However, no studies have investigated the pharyngeal pressure differences between these two swallowing tasks. Additional insights into task differences may be revealed through evaluation of pharyngeal pressure utilizing pharyngeal manometry. This research programme sought to clarify the role of M1 in reflexively and volitionally initiated pharyngeal swallowing. In order to understand M1 involvement in the execution of swallowing, comparative tasks that require known dependence on M1 were also included in this research programme. This research programme addressed the biomechanical changes in motor behaviours as a result of neural disruption during the performance of a number of motor tasks. This neural disruption was intrinsically generated through application of dual task (DT) paradigm and extrinsically generated using single pulse transcranial magnetic stimulation (TMS). A secondary aim of this research programme was to identify the differences in pharyngeal pressure generation between discrete and continuous swallowing. Methods: Twenty-four right handed participants (12 males, average age= 24.4, SD= 6.3) were recruited to this research programme. A number of motor tasks that vary in complexity were tested. These tasks included: volitional swallowing, reflexive swallowing, eyebrow movement, jaw movement and finger tapping with right, left, or bilateral index fingers. Participants performed multiple trials of several tasks in each study. Repetitions of tasks during a single session may affect performance due to factors such as fatigue or practice. A baseline study was undertaken to determine within-participant variability of measures across repeated trials. Following the baseline study, the role of M1 in pharyngeal swallowing was investigated in two main studies in counter balanced order. The role of M1 in pharyngeal swallowing was evaluated by investigating swallowing parameters during neural disruption using a DT paradigm. Participants performed tasks in isolation (baseline) and with interference that consisted of pairing swallowing with comparative task that activates M1 (fingers tapping and eyebrow movement tasks). In the other study, single pulse TMS was utilized to create an electrophysiological disruption to the areas of M1 associated with muscular representation of a number of motor behaviours (swallowing tasks, jaw movement and fingers tapping tasks). Stimulation was provided to both hemispheres in random order to evaluate laterality effects. Swallowing parameters and the performance of the other motor tasks were evaluated when performed with and without electrophysiological disruption. Differences in pharyngeal pressure generation between discrete and continuous swallowing were investigated using pharyngeal manometry. Pharyngeal pressures were recorded at three locations: upper pharynx, mid-pharynx and upper esophageal sphincter (UES) during four swallowing types: discrete saliva swallowing, discrete 10 ml swallowing, volitional continuous swallowing, and reflexive continuous swallowing. The research paradigm used in this research programme identified the effect of experimental conditions on the rate and regularity of task performance. In addition, pharyngeal manometry was utilised to measure the effect of experimental conditions on the pattern of the pharyngeal pressure generation during swallowing. Within subject differences from baseline were identified by means of Repeated Measures Analyses of Variance (RM-ANOVA). Results: Initial analysis of the data revealed that repetition of tasks within a session did not affect the rate and regularity of voluntary corticospinal tasks, voluntary corticiobulbar tasks nor swallowing tasks. In addition, repeating the swallowing tasks during a session did not affect pharyngeal pressure as measured by pharyngeal manometry. When motor tasks were performed concurrently in the DT paradigm, rate and regularity of eyebrow movements were significantly decreased when paired with swallowing tasks, whereas rate and regularity of swallowing were significantly decreased when paired with left finger tapping, but not right finger tapping. However, there was no significant effect of any task on the pattern of pharyngeal pressure generation. Extrinsically generated disruption using TMS significantly reduced rate and regularity of finger tapping tasks and regularity of jaw movement and swallowing tasks. In addition, interruption of pharyngeal M1 during the volitional swallowing task produced significant increase in the duration but not the amplitude of the pharyngeal pressure. Pharyngeal pressure generation differed between swallowing types and boluses types, in that saliva swallowing produced longer pharyngeal pressure duration and lower nadir pressure than water swallows. Discrete water bolus swallowing produced longer UES opening compared to both saliva swallowing or continuous water swallowing. Conclusion: The results of this research programme provided valuable methodological information regarding the effect of trials on task performance as well as identifying pharyngeal pressure differences between discrete and continuous swallowing. In addition to the methodological contribution, this research programme expanded on previous knowledge of neural control of swallowing, in that it extended the findings regarding potential role of M1 in pharyngeal swallowing. Given the absent effect of task repetition on the performance of corticospinal and corticobulbar motor tasks, it is speculated that outcomes of research investigating the effect of experimental manipulation on motor tasks performance is due to the experimental tasks, rather than natural variance in the data. The effect of swallowing on the rate and regularity of eyebrow movement, when performed concurrently using DT paradigm, suggest bilateral functional overlapping to a significant degree between neural substrates that control swallowing and orofacial muscles. These results offer partial support of bilateral representation of swallowing in the cortex. In addition, results further revealed potential involvement of right M1 in the regulation of pharyngeal swallowing as evidenced by a disruptive effect of left finger tapping on the rate and regularity of swallowing. The results from the hemispheric TMS disruption study support the active involvement M1 in the execution of voluntary corticospinal and corticobulbar motor tasks. In addition, the current findings extended previous knowledge of neural control of pharyngeal swallowing by documenting the effect of neural disruption on the regularity and pharyngeal pressure measures during volitional and reflexive swallowing. The current programme documented potential role of M1 in the control of pharyngeal swallowing possibly by modulating the motor plan at the swallowing CPG in the brainstem. This project is the first to document pharyngeal pressure differences between discrete and continuous swallowing. These findings contribute valuable information to the swallowing literature as limited number of studies investigated the biomechanical differences between discrete and continuous liquid ingestion. This knowledge will assist clinicians and researchers in identifying the pharyngeal pressure differences between normal and abnormal swallowing in different swallowing types and ultimately guide their rehabilitation decisions. Data from this research programme will add to the existing knowledge of neurophysiology of swallowing, thereby facilitating understanding of swallowing pathophysiology which is crucial for appropriate management of swallowing disorders

Preparation and characterization of low concentrated suspensions of industrial nanoparticles

В настоящее время одним из наиболее первпективных и развивающихся методов исследования размеров наночастиц является масс-спектрометрия с индуктивно связанной плазмой по методу единичных частиц (SP ICP-MS), позволяющая исседовать частицы в очень низких эколонически-эквивалентных концентарциях. В настоящей работе рассмотрены различные метдики приготовления суспензий промышленных наночастиц для исследования с помощью SP ICP-MS, выбраны оптимальные условия и представлены первые результаты

Stratosphere troposphere coupling: the influence of volcanic eruptions

Stratospheric sulfate aerosols produced by major volcanic eruptions modify the radiative and dynamical properties of the troposphere and stratosphere through their reflection of solar radiation and absorption of infrared radiation. At the Earth's surface, the primary consequence of a large eruption is cooling, however, it has long been known that major tropical eruptions tend to be followed by warmer than usual winters over the Northern Hemisphere (NH) continents. This volcanic "winter-warming" effect in the NH is understood to be the result of changes in atmospheric circulation patterns resulting from heating in the stratosphere, and is often described as positive anomalies of the Northern Annular Mode (NAM) that propagate downward from the stratosphere to the troposphere. In the southern hemisphere, climate models tend to also predict a positive Southern Annular Mode (SAM) response to volcanic eruptions, but this is generally inconsistent with post-eruption observations during the 20th century. We review present understanding of the influence of volcanic eruptions on the large scale modes of atmospheric variability in both the Northern and Southern Hemispheres. Using models of varying complexity, including an aerosol-climate model, an Earth system model, and CMIP5 simulations, we assess the ability of climate models to reproduce the observed post-eruption climatic and dynamical anomalies. We will also address the parametrization of volcanic eruptions in simulations of the past climate, and identify possibilities for improvemen

The impact of wave-mean flow interaction on the Northern Hemisphere polar vortex after tropical volcanic eruptions

The current generation of Earth system models that participate in the Coupled Model Intercomparison Project phase 5 (CMIP5) does not, on average, produce a strengthened Northern Hemisphere (NH) polar vortex after large tropical volcanic eruptions as suggested by observational records. Here we investigate the impact of volcanic eruptions on the NH winter stratosphere with an ensemble of 20 model simulations of the Max Planck Institute Earth system model. We compare the dynamical impact in simulations of the very large 1815 Tambora eruption with the averaged dynamical response to the two largest eruptions of the CMIP5 historical simulations (the 1883 Krakatau and the 1991 Pinatubo eruptions). We find that for both the Tambora and the averaged Krakatau-Pinatubo eruptions the radiative perturbation only weakly affects the polar vortex directly. The position of the maximum temperature anomaly gradient is located at approximately 30°N, where we obtain significant westerly zonal wind anomalies between 10hPa and 30hPa. Under the very strong forcing of the Tambora eruption, the NH polar vortex is significantly strengthened because the subtropical westerly wind anomalies are sufficiently strong to robustly alter the propagation of planetary waves. The average response to the eruptions of Krakatau and Pinatubo reveals a slight strengthening of the polar vortex, but individual ensemble members differ substantially, indicating that internal variability plays a dominant role. For the Tambora eruption the ensemble variability of the zonal mean temperature and zonal wind anomalies during midwinter and late winter is significantly reduced compared to the volcanically unperturbed period

Проблемы молодых специалистов получения образования в Российской Федерации и применение полученных знаний в республике Казахстан по специальности бухгалтерский учет

В данной статье рассмотрено значение международных стандартах финансовой отчетности. Определены сходства и различия ведения бухгалтерского учета в Российской Федерации и Республике Казахстан. Выявлены проблемы получения образования специалистом на территории России и применения полученных знаний в Республике Казахстан. И рассмотрена возможность подготовки высококвалифицированных специалистов в Российской Федерации

Disproportionately strong climate forcing from extratropical explosive volcanic eruptions

Funding: This work was supported by the Federal Ministry for Education and Research in Germany (BMBF) through the research program “MiKlip” (grant nos FKZ:01LP130B, 01LP1130A and 01LP1517B). M.T. additionally acknowledges support by the Deutsche Forschungsgemeinschaft (DFG) in the framework of the priority programme “Antarctic Research with comparative investigations in Arctic ice areas” through grant no. TO 967/1-1. K.K. and M.Sigl acknowledge support through the NFR project “VIKINGS” (project no. 275191). C.T. additionally acknowledges support from the European Union project StratoClim (FP7-ENV.2013.6.1-2). Computations were performed at the German Climate Computer Center (DKRZ).Extratropical volcanic eruptions are commonly thought to be less effective at driving large-scale surface cooling than tropical eruptions. However, recent minor extratropical eruptions have produced a measurable climate impact, and proxy records suggest that the most extreme Northern Hemisphere cold period of the Common Era was initiated by an extratropical eruption in 536 ce. Using ice-core-derived volcanic stratospheric sulfur injections and Northern Hemisphere summer temperature reconstructions from tree rings, we show here that in proportion to their estimated stratospheric sulfur injection, extratropical explosive eruptions since 750 ce have produced stronger hemispheric cooling than tropical eruptions. Stratospheric aerosol simulations demonstrate that for eruptions with a sulfur injection magnitude and height equal to that of the 1991 Mount Pinatubo eruption, extratropical eruptions produce time-integrated radiative forcing anomalies over the Northern Hemisphere extratropics up to 80% greater than tropical eruptions, as decreases in aerosol lifetime are overwhelmed by the enhanced radiative impact associated with the relative confinement of aerosol to a single hemisphere. The model results are consistent with the temperature reconstructions, and elucidate how the radiative forcing produced by extratropical eruptions is strongly dependent on the eruption season and sulfur injection height within the stratosphere.PostprintPeer reviewe

Forced exercise-induced osteoarthritis is attenuated in mice lacking the small leucine-rich proteoglycan decorin

Objective Interterritorial regions of articular cartilage matrix are rich in decorin, a small leucine-rich proteoglycan and important structural protein, also involved in many signalling events. Decorin sequesters transforming growth factor P (TGFP3), thereby regulating its activity. Here, we analysed whether increased bioavailability of TGF3 in decorin-deficient (Dcn(-/-)) cartilage leads to changes in biomechanical properties and resistance to osteoarthritis (OA). Methods Unchallenged knee cartilage was analysed by atomic force microscopy (AFM) and immunohistochemistry. Active transforming growth factor beta-1 (TGF beta 1) content within cultured chondrocyte supernatants was measured by ELISA. Quantitative realtime (RT)-PCR was used to analyse mRNA expression of glycosaminoglycan (GAG)-modifying enzymes in C28/12 cells following TGFf31 treatment. In addition, OA was induced in Dcn(-/-) and wild-type (WT) mice via forced exercise on a treadmill. Results AFM analysis revealed a strikingly higher compressive stiffness in Dcn(-/-) than in WT cartilage. This was accompanied by increased negative charge and enhanced sulfation of GAG chains, but not by alterations in the levels of collagens or proteoglycan core proteins. In addition, decorin-deficient chondrocytes were shown to release more active TGF beta 1. Increased TGF beta signalling led to enhanced Chstl 1 sulfotransferase expression inducing an increased negative charge density of cartilage matrix. These negative charges might attract more water resulting in augmented compressive stiffness of the tissue. Therefore, decorin-deficient mice developed significantly less OA after forced exercise than WT mice. Conclusions Our study demonstrates that the disruption of decorin -restricted TGF beta signalling leads to higher stiffness of articular cartilage matrix, rendering joints more resistant to OA. Therefore, the loss of an important structural component can improve cartilage homeostasis

The Flexible Ocean and Climate Infrastructure Version 1 (FOCI1): Mean State and Variability

A new Earth system model, the Flexible Ocean and Climate Infrastructure (FOCI), is introduced. A first version of FOCI consists of a global high-top atmosphere (ECHAM6.3) and an ocean model (NEMO3.6) as well as sea ice (LIM2) and land surface model components (JSBACH), which are coupled through the OASIS3-MCT software package. FOCI includes a number of optional modules which can be activated depending on the scientific question of interest. In the atmosphere, interactive stratospheric chemistry can be used (ECHAM6-HAMMOZ) to study, for example, the effects of the ozone hole on the climate system. In the ocean, a biogeochemistry model (MOPS) is available to study the global carbon cycle. A unique feature of FOCI is the ability to explicitly resolve mesoscale ocean eddies in specific regions. This is realized in the ocean through nesting; first examples for the Agulhas Current and the Gulf Stream systems are described here. FOCI therefore bridges the gap between coarse-resolution climate models and global high-resolution weather prediction and ocean-only models. It allows to study the evolution of the climate system on regional and seasonal to (multi-) decadal scales. The development of FOCI resulted from a combination of the long-standing expertise in ocean and climate modeling in several research units and divisions at GEOMAR. FOCI will thus be used to complement and interpret long-term observations in the Atlantic, enhance the process understanding of the role of mesoscale oceanic eddies for large-scale oceanic and atmospheric circulation patterns, study feedback mechanisms with stratospheric processes, estimate future ocean acidification, improve the simulation of the Atlantic Meridional Overturning Circulation changes and their influence on climate, ocean chemistry and biology. In this paper we present both the scientific vision for the development of FOCI as well as some technical details. This includes a first validation of the different model components using several configurations of FOCI. Results show that the model in its basic configuration runs stably under pre-industrial control as well as under historical forcing, and produces a mean climate and variability which compares well with observations, reanalysis products and other climate models. The nested configurations reduce some long-standing biases in climate models and are an important step forward to include the atmospheric response in multi-decadal eddy-rich configurations

Engineering geological assessment of selected landslide dams formed from the 1929 Murchison and 1968 Inangahua earthquakes

This study investigated the characteristics of 26 failed and non-failed landslide dams (Murchison dataset) formed in the northern part of the South Island, New Zealand, from the 1929 Murchison and 1968 Inangahua earthquakes. The dataset was compiled from a combination of engineering geological mapping, field investigations, aerial photography interpretation and a review of existing literature. Current analysis techniques have been applied to the investigated landslide dams to assess their ability to accurately predict the post-formation development (or ‘evolution’) of the dam overtime. This has allowed the recognition of a number of additional landslide dam attributes that influence long-term stability, allowing modification of the stability analysis techniques in current use. Dam, lake, catchment and landslide characteristics were collated and analysed for the Murchison dataset by distinguishing failed from non-failed landslide dams, and then assessing the parameters common to both. Parameters that influence the post-formation development of selected landslide dams in the dataset include the dam volume, catchment area above the point of blockage, average block size of material comprising the dam, slope angle of the downstream dam face, and rock mass anal material characteristics in the source area of the dam-forming landslide. The stability of the dams in the Murchison dataset was not significantly affected by rock type, landslide movement, or the state, distribution and style of the dam-forming landslide. Existing geomorphic indices were applied to selected dams in the dataset. The Impoundment, Blockage and Dimensionless Blockage Indices (Casagli and Ermini (1999); Ermini and Casagli (2003)) predicted the correct post-formation development for 58, 86, and 81% of the selected landslide dams in the Murchison dataset, respectively. Four landslide dams covering both failed and non-failed types were investigated in detail to assist with this analysis, two being stable dams impounding lakes, and two having failed ‘catastrophically’ post-formation. Detailed investigation was carried out on Lake Stanley landslide dam, which agrees with all three indices predicting post-formation development, and of Lake Matiri, Ram Creek and Rain Peak landslide dams for which the indices incorrectly predict their post formation development. This investigation has shown that the average block size (D₅₀) of the dam material strongly influences the post-formation development of the four dams studied in detail. Dams consisting of material. with larger(> 200mm) average block sizes correspond to stable dams; while those with small(< 100mm) average block size correspond to failed dams. Rainfall duration/ intensity and slope angle of the downstream dam face were also found to influence post-formation development of the dams. The recently formed and failed Poerua landslide dam on the West Coast of the South Island was included in the geomorphic index evaluation because of the excellent documentation available, together with the prediction of its long-term stability using the index approach. The D₅₀ of the material forming the landslide dam, and the landslide dam's basal (or footprint) length, were incorporated with the parameters used in the existing geomorphic indices to produce a new geomorphic index, the Modified Dimensionless Blockage Index (MDBI). This is defined as: [complicated equation here] where Ac is the catchment area (m²), At is the lake area (m²), Hd is the height of the dam (m), Lʄ is the length of the dam footprint (m), Vd is the volume of the dam (m³), and Vd is the volume of the mean block size forming the dam (cube of the D₅₀ expressed in m³). Calculated MDBI values for the two stable landslide dams (Lake Stanley and Lake Matiri) are less than 10 (8.90 and 6.94 respective]y), while those for three failed landslide dams (Rain Peak, Ram Creek and Poerua) are greater than 10 (10.75, 10.80 and 14.9, respective]y). This suggests that the MDBI can be tentative]y used as a tool in forecasting the post-formation development of a landslide dam, with MDBI values > 10 corresponding to catastrophic dam failure, and an MDBI value < 10 corresponding to probable longer-term stability. However, it is recommended that a wider landslide dam dataset be applied to the MDBI to further test its accuracy, and to refine the parameters used both for short-term stability assessment following impoundment, and for longer-term prediction of post-formation dam (and lake) development. Rainfall duration and maximum block size of the dam material also require further evaluation, and a refinement incorporating grading parameters (such as D₆₀/D₁₀) may provide a better estimation of the post-formation landslide dam development. It is clear from this study that the block size and grading of the landslide dam material (in particular matrix or block support) exert significant influence on dam longevity and evolution, and this is reflected in the substantial weighting given to D₅₀ in the MDBI