A Model for Performance Estimation of Flapping Foil Operating as Biomimetic Stream Energy Device

During the recent period intensive research has focused on the advancement of engineering and technology aspects concerning the development and optimization of wave and current energy converters driven by the need to increase the percentage of marine renewable sources in the energy-production mix, particularly from offshore installations. Most stream energy-harvesting devices are based on hydro-turbines, and their performance is dependent on the ratio of the blade-tip speed to incident-flow speed. As the oncoming speed of natural-occurring currents varies randomly, there is a penalty for the latter device’s performance when operating at non-constant tip-speed ratio away from the design value. Unlike conventional turbines that are characterized by a single degree of freedom rotating around an axis, a novel concept is examined concerning hydrokinetic energy converters based on oscillating hydrofoils. The biomimetic device includes a rotating, vertically mounted, biomimetic wing, supported by an arm linked at a pivot point on the mid-chord. Activated by a controllable self-pitching motion the system performs angular oscillations around the vertical axis in incoming flow. In this work, the performance of the above flapping-foil, biomimetic flow energy harvester is investigated by application of a semi-3D model based on unsteady hydrofoil theory and the results are verified by comparison to experimental data and a 3D boundary element method based on vortex rings. By systematical application of the model the power extraction and efficiency of the system is presented for various cases including different geometric, mechanical, and kinematic parameters, and the optimal performance of the system is determined

Adrenal function in non-septic long-stay critically ill patients: evaluation with the low-dose (1 mu g) corticotropin stimulation test

Objective: To investigate the adrenal function in non-septic, long-stay critically ill patients. Design: Prospective, consecutive study. Setting: General intensive care unit in a university hospital. Patients: Forty-three non-septic patients with protracted critical illness. Interventions: A morning blood sample was first obtained to measure baseline plasma cortisol. Subsequently, 1 mug of corticotropin (ACTH, Synacthene) was injected intravenously and 30 min later a second blood sample was drawn to determine stimulated plasma cortisol. Patients having a stimulated cortisol level of at least 18 pg/dl were defined as responders. In 36 patients, morning interleukin-6 (IL-6) was also measured. Measurements and results: Baseline and stimulated plasma cortisol were 16.8 +/- 4.1 pg/dl and 21.2 +/- 5.1 pg/dl, respectively. Interleukin-6 was high (median 39.3 pg/ml, interquartile range 24.9-86.6 pg/ml) and correlated negatively with stimulated plasma corti-sol (r=-0.40, p<0.05). Of the 43 patients studied, 31 patients (72%) were responders and 12 patients (28%) were non-responders to the ACTH stimulation test. Overall, 18 patients died and 25 patients survived to hospital discharge. Non-responders had significantly higher IL-6 levels compared to responders (106 +/- 73 versus 48 42 pg/ml, p<0.05), whereas mortality rate was comparable in the two groups (50% versus 38%, p=0.74). Conclusions: Circulating plasma IL-6 levels are high during protracted critical illness, and are partially responsible for the relative adrenal insufficiency found in a subset of severely ill patients

Age and education adjusted normative data and discriminative validity for Reys Auditory Verbal Learning Test in the elderly Greek population

Reys Auditory Verbal Learning Test (RAVLT) is a widely used neuropsychological test to assess episodic memory. In the present study we sought to establish normative and discriminative validity data for the RAVLT in the elderly population using previously adapted learning lists for the Greek adult population. We administered the test to 258 cognitively healthy elderly participants, aged 60-89 years, and two patient groups (192 with amnestic mild cognitive impairment, aMCI, and 65 with Alzheimers disease, AD). From the statistical analyses, we found that age and education contributed significantly to most trials of the RAVLT, whereas the influence of gender was not significant. Younger elderly participants with higher education outperformed the older elderly with lower education levels. Moreover, both clinical groups performed significantly worse on most RAVLT trials and composite measures than matched cognitively healthy controls. Furthermore, the AD group performed more poorly than the aMCI group on most RAVLT variables. Receiver operating characteristic (ROC) analysis was used to examine the utility of the RAVLT trials to discriminate cognitively healthy controls from aMCI and AD patients. Area under the curve (AUC), an index of effect size, showed that most of the RAVLT measures (individual and composite) included in this study adequately differentiated between the performance of healthy elders and aMCI/AD patients. We also provide cutoff scores in discriminating cognitively healthy controls from aMCI and AD patients, based on the sensitivity and specificity of the prescribed scores. Moreover, we present age-and education-specific normative data for individual and composite scores for the Greek adapted RAVLT in elderly subjects aged between 60 and 89 years for use in clinical and research settings. © 2015 Taylor and Francis

Impaired Verb-Related Morphosyntactic Production in Multiple Sclerosis: Evidence From Greek

Background: A recent systematic review found that language deficits are not very common in individuals with multiple sclerosis (MS). However, there are significant gaps in our knowledge about language abilities in MS. For instance, morphosyntactic production has not been explored adequately thus far. This study investigated verb-related morphosyntactic production in MS focusing on Greek, a morphologically rich language. Methods: A sentence completion task tapping into the production of subject–verb agreement, time reference/tense, and grammatical aspect was administered to 39 Greek-speaking individuals with MS [25 individuals with relapsing-remitting MS (RRMS group) and 14 individuals with secondary progressive MS (SPMS group)]. The task included only regular verbs. Generalized linear mixed-effects models were used to investigate the ability of individuals with MS to produce the above-mentioned morphosyntactic categories. Results: Overall, the RRMS and SPMS groups performed significantly worse than their matched control groups. Moreover, all four groups performed significantly worse on grammatical aspect than on subject–verb agreement and time reference. The difference between subject–verb agreement and time reference was not significant in any of the four groups. The overall performances of the RRMS and SPMS groups did not differ significantly. Conclusion: Individuals with MS are impaired in verb-related morphosyntactic production. Moreover, the pattern of performance of individuals with MS is identical to that exhibited by neurologically healthy individuals. Thus, the production performance of individuals with MS on verb inflection differs from that of healthy controls quantitatively but not qualitatively. © Copyright © 2020 Fyndanis, Messinis, Nasios, Dardiotis, Martzoukou, Pitopoulou, Ntoskou and Malefaki

Do Secondary Progressive Multiple Sclerosis patients benefit from Computer- based cognitive neurorehabilitation? A randomized sham controlled trial

Background: Cognitive impairment is common in multiple sclerosis (MS), but deficits tend to be more pronounced in progressive MS, negatively impacting daily functional capacity. Despite this, most cognitive rehabilitation (CR) interventions to date have focused on relapsing-remitting MS (RRMS). Moreover, information on the efficacy of CR in progressive MS is limited and controversial. The present study investigated the efficacy of a home based, computer assisted cognitive rehabilitation (HBCACR) intervention (RehaComTM software) exclusively in a Secondary Progressive Multiple Sclerosis (SPMS) sample. Methods: This was a randomized, multi site, sham controlled trial. Thirty six (36) individuals with SPMS, naïve to the RehaCom software, with cognitive deficits were randomized to the treatment (IG; n= 19) or control group condition (CG; n=17). Treatment with the RehaCom modules consisted of 24 domain and task specific, 45 minute session's over an 8-week period, three sessions per week, applied by each patient at home. The CG completed non specific computer based activities at home with the same frequency and duration. Primary cognitive outcome measures included the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS) battery, and secondary outcome measures for depression (BDI-FS), fatigue (MFIS), and quality of life (EuroQol EQ-5D) visual analogue scale (VAS). Results: The two groups were well matched on demographic and clinical characteristics, cognitive reserve and severity of cognitive deficits at baseline assessment. At post treatment assessment the IG group showed significant improvements with large effect sizes; in verbal learning [z = -4.759, p <.0005, g = 2.898], visuospatial memory [z = -3.940, p <.0005, g = 1.699] and information processing speed [z= -4.792, p <.0005, g = 2.980], compared with the sham control group. We also found significant between group differences on physical [z=-3.308, p = .001, g= -.604], cognitive [z = -4.011, p <.0005, g = -1.654], psychosocial [z= 3.308, p = .010, g = -.940], and general fatigue impact [z= -2.623, p = .008, g = -.519], depression severity [z = -2.730, p = .006, g = -.519], and quality of life [z= -4.239, p <.0005, g = -1.885] in favor of the treated group. Conclusion: These data provide the first evidence supporting the efficacy of computer based restorative cognitive rehabilitation applied at home exclusively in SPMS patients, suggesting that adaptive neuroplasticity may occur after functional cognitive training in progressive MS. Improved cognitive functioning in combination with mood augmentation appear to have ameliorated fatigue, which impacted daily functioning activity and culminated in improved health related quality of life. © 2020 Elsevier B.V