BACKGROUND A blunted heart rate reserve (HRR) during dipyridamole stress echocardiography (DSE) is a prognostically unfavorable sign of cardiac autonomic dysfunction. Short-term adjustments of heart rate (HR) are thought to rise from changes in neural input to the heart. DSE is applied in potential heart donors to rule out underlying coronary artery disease and left ventricular dysfunction. AIM to assess HRR during DSE in brain death. METHODS We enrolled 2 Groups: Group 1 (n=49, 22 men, 54.6±8.8 years) with patients in brain death enrolled in the nationwide marginal donor heart recruiting program; Group 2 (n=49, 18 men, 66.4±12.0 years) referred to DSE for suspected or known coronary artery disease. All underwent DSE (0.84 mg/kg in 6') by quality-controlled readers certified via web-based training (1487/CE Lazio-1). We assessed left ventricular contractile reserve (LVCR) as stress/rest ratio of force (systolic blood pressure /end-systolic volume). HRR was calculated as the peak/rest HR ratio from 12-lead EKG. RESULTS The 2 groups were similar for prevalence of inducible ischemia (4/49 vs 9/49, p=ns). Group 1 showed higher resting HR (Group 1= 88.1±15.5 vs Group 2= 66.5±11.5 bpm, p<0.01) and similar peak HR (Group 1=94.7±15.3 vs Group 2=89.5±19.3 bpm, p=0.144), with blunted HRR (Group 1= 1.08±0.10 vs Group 2= 1.36±0.31 bpm, p<0.01). HRR was unrelated to LVCR. CONCLUSIONS HRR is almost abolished and unrelated to LVCR in brain-dead patients during DSE. The modulation of neural input to the heart is essential to determine HRR, and plays no significant role in determining the inotropic response during DSE.
Diabetes mellitus (DM) as a chronic condition is a growing global problem. Its numerous complications, including ocular diseases, affect patients’ quality and length of life. Metformin is an effective, safe, and inexpensive first-line pharma-cotherapy for type 2 diabetes (T2D). The current evidence indicates metformin’s multiple sites of action and multiple molecular mechanisms leading to its beneficial impact on metabolism, inflammation, oxidative stress, aging, as well as to its cardiovascular, neurological, bone, and antiproliferative properties. These impacts are the result of its acting on adenosine monophosphate-activated protein kinase (AMPK)-dependent and AMPK-independent pathways. Limited data suggest the protective role of metformin on microvascular ocular complications, including retinopathy, glaucoma, and age-related macular degeneration in patients with T2D. However, to confirm its mentioned protective and therapeutic effects, more large, randomized, double-blind, and placebo-controlled clinical studies are needed.
Glucosylceramidase (GCase) is a lysosomal enzyme that catalyzes the cleavage of β-glucosidic linkage of glucocerebroside (GC) into glucose and ceramide; thereby, plays an essential function in the degradation of complex lipids and the turnover of cellular membranes. The growing list of 460 mutations in the gene coding for it—glucosylceramidase beta acid 1 (GBA1)—is reported to abolish its catalytic activity and decrease its enzyme stability, associating it with severe health conditions such as Gaucher disease (GD), Parkinson Disease and Dementia with Lewy bodies. Although the three-dimensional structure of wild type glucosylceramidase is elucidated, little is known about its features in human cells. Moreover, alternative sources of GCase that prove to be effective in the treatment of diseases with enzyme treatment therapies, impose the need for simple and cost-effective procedures to study the enzyme behaviour. This work, for the first time, shows a well established, yet simple, cost- and time-efficient protocol for the study of GCase enzyme in human leukocytes by the artificial substrate PNPG. Characterization of the enzyme in human leukocytes for activation parameters (optimal pH, Km, and Vmax) and enzyme inhibition, was done. The results indicate that the optimum pH of GCase enzyme with PNPG is 5.1. The Km and Vmax values were 12.6mM and 333 U/mg, respectively. Gluconolactone successfully inhibits GCase in a competitive manner, with a Ki value of 0.023 mM and IC 50 of 0.047 mM. Glucose inhibition was uncompetitive with a Ki of 1.94 mM and IC50 of 55.3 mM. This is the first report for the inhibitory effect of glucose, δ-gluconolactone on leukocyte GCase activity.
In this paper, we focus on the problem of blind joint calibration of multiband transceivers and time-delay (TD) estimation of multipath channels. We show that this problem can be formulated as a particular case of covariance matching. Although this problem is severely ill-posed, prior information about radio-frequency chain distortions and multipath channel sparsity is used for regularization. This approach leads to a biconvex optimization problem, which is formulated as a rank-constrained linear system and solved by a simple group Lasso algorithm. Numerical experiments show that the proposed algorithm provides better calibration and higher resolution for TD estimation than current state-of-the-art methods.
The present study investigates the influence of partial cement substitution with biomass ash on the corrosion behaviour of steel embedded in the mortar. To evaluate this influence, corrosion parameters of steel in mortar exposed to tap water and 3.5 wt% NaCl solution were monitored over a period of 50 days. The electrochemical cell consisted of a steel plate as a working electrode, covered with a layer of mortar that was exposed to the testing solution. Open‐circuit potential and linear polarisation were used to monitor changes in corrosion behaviour, whereas electrical impedance spectroscopy was used to evaluate the conductivity of the matrix. Additional to corrosion parameters, the chloride migration coefficient was tested after 28 days. On the basis of the results, it was observed that mortars with biomass ash provide equal or better protection for embedded steel, compared with the reference mortar. Mortars that performed slightly better than the reference mortar and other mortars were prepared with ashes with a higher amount of pozzolanic oxides.
Leukocytes are isolated by centrifugation after specific lysis of erythrocytes
In this article, we introduce Wireless 2.0, the future generation of wireless communication networks, in which the radio environment becomes controllable and intelligent by leveraging the emerging technologies of reconfigurable metasurfaces (RMSs) and artificial intelligence (AI). In particular, we emphasize AI-based computational methods and commence with an overview of the concept of intelligent radio environments (IREs) based on RMSs. Then, we elaborate on data management aspects, the requirements of supervised learning by examples, and the paradigm of reinforcement learning to learn by acting. Finally, we highlight numerous open challenges and research directions.
Twenty years after Povinelli’s “Folk Physics for Apes”, this paper assesses how researchers have made claims about animal physical cognition, and the statistical inferences that have been used to support them. These data are relevant in light of the current replicability issues facing science. We surveyed 116 published experiments from 63 papers on physical cognition, which included data from 43 different species of animals. Across these experiments most sample sizes were small, with often fewer than 10 animals being tested. However, in contrast to related psychological disciplines, we found that only 62% of our sample of physical cognition research made positive claims. This suggests that animal physical cognition does not have a strong publication bias towards positive results. Furthermore, we found evidence that researchers are making many true statistical inferences at the individual level, i.e. whether individual animals pass certain tests of physical cognition or not. In contrast, the strength of evidence of statistical effects at the group level was weaker and consistent with many effect sizes being overestimated. Overall, our analysis provides a cautiously optimistic analysis of reliability and bias in animal physical cognition research, however it is nevertheless likely that a non-negligible proportion of results will be difficult to replicate.
Brain derived neurotrophic factor (BDNF) has been implicated in the pathophysiology of schizophrenia. As BDNF regulates axonal and dendritic growth, altered BDNF levels in schizophrenia patients might underlie changes in structural connectivity that have been identified by magnetic resonance imaging (MRI). We investigated a possible correlation between BDNF serum levels, fiber tract architecture, and regional grey matter volumes in 19 schizophrenia patients and a gender- and age-matched control group. Two patients had to be excluded due to abnormalities in their MRI scans. Serum samples were obtained to determine BDNF levels, and T1- as well as diffusion-weighted sequences were acquired. We, then, investigated correlations between BDNF serum levels with neuroimaging parameters, using Voxel-based Morphometry (VBM) and Tract-based Spatial Statistics (TBSS). We found a significant negative correlation between BDNF serum levels and FA values in the right inferior fronto-occipital fasciculus and the right superior longitudinal fasciculus. These regions also showed a decrease in AD values in schizophrenia patients. Grey matter volumes were reduced in patients but there was no correlation between regional grey matter volumes and BDNF. The right superior longitudinal fasciculus has been repeatedly identified to exhibit microstructural changes in schizophrenia patients. Our findings of a negative correlation between BDNF and FA values in patients might indicate that BDNF is upregulated to compensate decreased structural connectivity as it induces neural plasticity and shows increased levels in damaged tissue. These findings of our pilot study are encouraging leads for future research in larger samples.
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