ABSTRACT
Running is a basic form of human locomotion and one of the most popular sports worldwide. While the leg biomechanics of running have been studied extensively, few studies have focused on upper-body movement. However, an effective arm swing and longitudinal rotation of the shoulders play an important role in running efficiency as they must compensate for the longitudinal torques generated by the legs. The aim of this study is to assess the upper-body rotation using wearable inertial sensors and to elucidate its relation to energy expenditure. Eighty-six junior elite middle- and long-distance runners (37 female, 49 male) performed an incremental treadmill test with sensors attached on both shoulders, tibiae and the sacrum. The mean and total horizontal shoulder and pelvis rotations per stride were derived while energy costs were determined using respiratory gas analysis and blood sampling. Results show that shoulder and pelvis rotations increase with running speed. While shoulder rotation is more pronounced in female than in male runners, there is no sex difference for pelvis rotation. The energy cost of running and upper trunk rotation prove to be slightly negatively correlated. In conclusion, upper body rotation appears to be an individual characteristic influenced by a sex-specific body mass distribution.
ABSTRACT
Background: Freezing of Gait (FOG) is a motor symptom frequently observed in advanced Parkinson's disease. However, due to its paroxysmal nature and diverse presentation, assessing FOG in a clinical setting can be challenging. Before FOG can be fully investigated, it is critical that a reliable experimental setting is established in which FOG can be evoked in a standardized manner, but the efficacy of various gait tasks and triggers for eliciting FOG remains unclear. Objectives: This study aimed to conduct a systematic review of the existing literature and evaluate the available evidence for the relationship between specific motor tasks, triggers, and FOG episodes in individuals with Parkinson's disease (PwPD). Methods: We conducted a literature search on four online databases (PubMed, Web of Science, EMBASE, and Cochrane Library) using the keywords "Parkinson's disease," "Freezing of Gait", "triggers" and "tasks". A total of 128 articles met the inclusion criteria and were included in our analysis. Results: The review found that a wide range of gait tasks were employed in studies assessing FOG among PD patients. However, three tasks (turning, dual tasking, and straight walking) emerged as the most frequently used. Turning (28%) appears to be the most effective trigger for eliciting FOG in PwPD, followed by walking through a doorway (14%) and dual tasking (10%). Conclusion: This review thereby supports the utilisation of turning, especially a 360-degree turn, as a reliable trigger for FOG in PwPD. This finding could be beneficial to clinicians conducting clinical evaluations and researchers aiming to assess FOG in a laboratory environment.
ABSTRACT
Future climate projections show a marked increase in Greenland Ice Sheet (GrIS) runoff during the 21st century, a direct consequence of the Polar Amplification signal. Regional climate models (RCMs) are a widely used tool to downscale ensembles of projections from global climate models (GCMs) to assess the impact of global warming on GrIS melt and sea level rise contribution. Initial results of the CMIP6 GCM model intercomparison project have revealed a greater 21st century temperature rise than in CMIP5 models. However, so far very little is known about the subsequent impacts on the future GrIS surface melt and therefore sea level rise contribution. Here, we show that the total GrIS sea level rise contribution from surface mass loss in our high-resolution (15 km) regional climate projections is 17.8 ± 7.8 cm in SSP585, 7.9 cm more than in our RCP8.5 simulations using CMIP5 input. We identify a +1.3 °C greater Arctic Amplification and associated cloud and sea ice feedbacks in the CMIP6 SSP585 scenario as the main drivers. Additionally, an assessment of the GrIS sea level contribution across all emission scenarios highlights, that the GrIS mass loss in CMIP6 is equivalent to a CMIP5 scenario with twice the global radiative forcing.
ABSTRACT
Imparting hydrophobicity to solid acid catalysts is critical to regulating their performances by allowing the creation of a less polar environment and improved partitioning of the reactants. Here we present different approaches for the preparation of silica-based catalysts comprising sulfonic acid (-SO3H) sites and hydrophobic decyl (-C10) chains by either simultaneous or sequential postfunctionalization of an azide-functionalized mesoporous silica platform. This set of hybrid bifunctional catalysts is compared in the model esterification of octanol with acetic acid, and the influence of the preparation methods together with the resulting site spatial distribution is discussed. In parallel, we show that pairing the two functional groups affords a maximum synergistic effect compared to more traditional mixed catalysts with random distributions of acid and hydrophobic functions.
ABSTRACT
Solid acid catalysts are central in our chemical industry and are major players in the valorization of bioresources. However, there is still a need to develop solid acid catalysts with enhanced acid strength and improved, or tunable, physicochemical profile to enhance the efficiency and sustainability of chemical processes. Here, a modular approach to tune the acid strength and surface polarity of silica-supported sulfonic acid catalysts, based on a versatile copper-catalyzed azide-alkyne cycloaddition (CuAAC)-based anchoring scheme, is presented. The CuAAC-formed triazole link was used to enhance the activity of the grafted sulfonic acids and to pair the acid sites with secondary hydrophobic functions. The beneficial effects of both the triazolium link and the paired hydrophobic site, as well as the optimal positioning of the sulfonic moiety on the triazole ring, are discussed in model esterification reactions.
ABSTRACT
The origin and pathophysiological background of multiple sclerosis (MS)-associated fatigue is poorly understood. There is no unifying concept of its nature and its determinants to date. This paper reviews possible influences of factors determining personality profile on fatigue in MS. Likewise, the role of psychological factors and their interaction with personality to promote fatigue is discussed. Current data suggest that fatigue, especially in early MS states, may be influenced by vulnerable personality traits and personality-associated features. Among them are depressive disease coping, avoidance behavior and inhibition, irritability, less extraversion, neuroticism, lower reward responsiveness, and somatization behavior. However, among the validated personality factors, no genuine influences that are independent of depression have been documented. From a psychological perspective, depressiveness, anxiety, and somatization may be relevant mediators of fatigue. Interesting to note that in early MS, a psychiatric diagnosis is significantly more likely than on a later stage of the disease and that fatigue and motivation might share neural circuits. It is hypothesized that psychological factors promote fatigue in MS by psychological distress and sustained neuroendocrine and neurovegetative stress response. Despite the limitations of data discussed in the paper, personality research might help to disentangle specific promoting factors of fatigue in MS. Further research efforts are warranted since they might open ways to early psychological intervention of MS-associated fatigue. This is all the more important since medication is insufficient until now.
