Disruption of the blood-brain barrier (BBB) is a key feature of various brain disorders. To assess its integrity a parametrization of dynamic magnetic resonance imaging (DCE MRI) with a contrast agent (CA) is broadly used. Parametrization can be done quantitatively or semi-quantitatively. Quantitative methods directly describe BBB permeability but exhibit several drawbacks such as high computation demands, reproducibility issues, or low robustness. Semi-quantitative methods are fast to compute, simply mathematically described, and robust, however, they do not describe the status of BBB directly but only as a variation of CA concentration in measured tissue. Our goal was to elucidate differences between five semi-quantitative parameters: maximal intensity (Imax), normalized permeability index (NPI), and difference in DCE values between three timepoints: baseline, 5 min, and 15 min (Δ5-0, Δ15-0, Δ15-5) and two quantitative parameters: transfer constant (Ktrans ) and an extravascular fraction (Ve). For the purpose of comparison, we analyzed DCE data of four patients 12-15 days after the stroke with visible CA enhancement. Calculated parameters showed abnormalities spatially corresponding with the ischemic lesion, however, findings in individual parameters morphometrically differed. Ktrans and Ve were highly correlated. Δ5-0 and Δ15-0 were prominent in regions with rapid CA enhancement and highly correlated with Ktrans . Abnormalities in Δ15-5 and NPI were more homogenous with less variable values, smoother borders, and less detail than Ktrans . Moreover, only Δ15-5 and NPI were able to distinguish vessels from extravascular space. Our comparison provides important knowledge for understanding and interpreting parameters derived from DCE MRI by both quantitative and semi-quantitative methods.
Handy Plant Efficiency Analyser (Handy PEA) provides a method for the high-throughput screening of photosynthetic germplasm. However, the large number of chlorophyll a fluorescence parameters (CFPs) from PEA and the inconsistency of CFP applications among studies greatly limit the accuracy of photosynthesis analyses. In this study, all 53 CFPs of 186 upland cotton cultivars (strains) were measured at 12:00 and 17:00 h. Thirty-two CFPs were selected according to biological importance, and the CFP relationships were determined. Differences in the response ability of cotton cultivars (strains) to high light intensity stress were demonstrated by the distribution of CFPs. Furthermore, the classification and evaluation of photosynthetic characteristics of cotton cultivars (strains) were carried out by Principal Component Analysis and Cluster Analysis. Finally, ten cotton cultivars (strains) with good photosynthetic performance were selected. This study provides a high-throughput method how to identify cotton germplasm resources with high photosynthetic efficiency.
We recently developed a chlorophyll a fluorescence method (activated F0 rise) for estimating if a light wavelength preferably excites PSI or PSII in plants. Here, the method was tested in green microalgae: Scenedesmus quadricauda, Scenedesmus ecornis, Scenedesmus fuscus, Chlamydomonas reinhardtii, Chlorella sorokiniana, and Ettlia oleoabundans. The Scenedesmus species displayed a plant-like action spectra of F0 rise, suggesting that PSII/PSI absorption ratio is conserved from higher plants to green algae. F0 rise was weak in a strain of C. reinhardtii, C. sorokiniana, and E. oleoabundans. Interestingly, another C. reinhardtii strain exhibited a strong F0 rise. The result indicates that the same illumination can lead to different redox states of the plastoquinone pool in different algae. Flavodiiron activity enhanced the F0 rise, presumably by oxidizing the plastoquinone pool during pre-illumination. The activity of plastid terminal oxidase, in turn, diminished the F0 rise, but to a small degree.
Increasing the efficiency of photosynthesis in sugarcane canopies is the key for improving crop yield. Herein, we evaluated the photosynthetic performance along the canopy of ten sugarcane cultivars and three Saccharum species. Canopy morphological traits were evaluated, and leaf gas exchange was measured in the first (sun-exposed, +1) and the fourth (shaded, +4) fully expanded leaves and under low- and high-light conditions. Similar photosynthetic capacity was found in leaves +1 and +4 under high light in genotypes with a high leaf area index and a high fraction of the sky blocked by the foliage (> 85%). Interestingly, such canopy characteristics cause low light availability to leaves +4, suggesting the photosynthetic acclimation of these leaves to self-shading in some genotypes. We highlight IACCTC06-8126 and CTC4 as those genotypes with higher canopy photosynthetic capacity, presenting high leaf area, high photosynthetic rates in sun-exposed leaves, and high responsiveness of shaded leaves to increasing light availability.
A large-scale piano key weir laboratory study was conducted to investigate the evolution of the scour process occurring in the downstream basin for two non-cohesive granular bed materials, including the analysis of scour-hole geometry and patterns at equilibrium. It was observed that hydraulic conditions, particularly tailwater level, significantly affect the scour mechanisms and equilibrium morphology, eventually resulting in scour depths that exceeded the weir height. Unprecedented insights on the scour dynamics are also provided, along with tools to estimate the time evolution and maximum scour depth, its location in the streamwise direction, and the maximum scour length.
Attention Deficit Hyperactivity Disorder (ADHD) is a unique disorder. It usually devel-ops in early childhood and, in 50% of cases, continues to be a lifelong disorder, which poses significant challenges for researchers and clini-cians. The new criteria set by the World Health Organization merged the category of Hyperki-netic Disorders and the ADHD category.This narrative review aims to explore and ease the adoption of the ADHD concept for clinicians and researchers who were used to working with Hyperkinetic Disorders by (1) analyzing the evolution of the ADHD concept from its estab-lishment in the Diagnostic and Statistical Man-ual of Mental Disorders, 3rd edition (DSM-III) until DSM-5; (2) comparing the contemporary concepts of ADHD in DSM-5 and Hyperkinetic Disorders in International Statistical Classifica-tion of Diseases and Related Health Problems (ICD-10); and (3) describing some new chal-lenges the ADHD concept will face in the future.The structure and the dimensions of the concept are explored, including some possible new core symptoms such as emotional dysregulation and mind wandering. Adult presentations of symp-toms of hyperactivity, impulsivity, and inatten-tion are presented. The recent challenges of the global pandemic of covid-19 are also addressed.In conclusion, the concept of ADHD has been dramatically improved since its establishment. However, the bio-psycho-social perspective needs to be better balanced in ADHD-related science. and Porucha pozornosti s hyperaktivitou (ADHD) je unikátní poruchou. Většinou se rozvine v raném dětství a v 50 % případů přerůstá v celoživotní poruchu, což přináší významné výzvy pro vý-zkumníky i odborníky v praxi. Nová kritéria vytvořená Světovou zdravotnickou organiza-cí spojila kategorie hyperkinetických poruch a ADHD. Cílem této narativní přehledové studie bylo prozkoumat a usnadnit osvojení koncep-tu ADHD odborníky a výzkumníky, kteří byli zvyklí pracovat s hyperkinetickými poruchami. 1) Byla analyzována evoluce konceptu ADHD od jeho ustanovení ve 3. edici Diagnostické-ho a statistického manuálu duševních poruch (DSM-III) až po DSM-5; 2) byly porovnány současné koncepty ADHD v DSM-5 a hyper-kinetické poruchy v Mezinárodní statistické klasifikaci nemocí a přidružených zdravotních problémů (MKN-10); a 3) byly popsány některé nové výzvy, kterým může koncept ADHD čelit v budoucnosti. Prozkoumány byly dimenze a struktura konceptu včetně potenciálních no-vých symptomů, jako jsou například emocio-nální dysregulace a tzv. mind wandering. Před-staveny byly také dospělé prezentace symptomů hyperaktivity, impulzivity a nepozornosti. Au-toři se dotkli také nedávných výzev spojených s globální pandemií covid-19. Závěrem lze kon-statovat, že koncept ADHD se od svého vzniku významně zlepšil. Ve vědeckém výzkumu zabý-vajícím se ADHD by však měla být více zohled-něna psycho-bio-sociální perspektiva.
Exercise can improve the cardiovascular health. However, the mechanism contributing to its beneficial effect on elderly patients with myocardial infarction is obscure. 20-month-old male Sprague-Dawley rats were used to establish myocardial infarction (MI) model by permanent ligation of the left anterior descending coronary artery (LAD) of the heart, followed by 4-week interval exercise training on a motor-driven rodent treadmill. The cardiac function, myocardial fibrosis, apoptosis, oxidative stress, and inflammatory responses were determined by using pressure transducer catheter, polygraph physiological data acquisition system, Masson's trichrome staining, and ELISA to evaluate the impact of post-MI exercise training on MI. Western blot were performed to detect the activation of AMPK/SIRT1/PGC-1α signaling in the hearts of aged rats. Exercise training significantly improved cardiac function and reduced the cardiac fibrosis. In infarcted heart, the apoptosis, oxidative stress, and inflammation were significantly reduced after 4-week exercise training. Mechanistically, AMPK/SIRT1/PGC-1α pathway was activated in the myocardial infarction area after exercise training, which might participate in the protection of cardiac function. Exercise training improves cardiac function in MI rats through reduction of apoptosis, oxidative stress, and inflammation, which may mediate by the activation of AMPK/SIRT1/PGC-1α signaling pathway.
Exercise tolerance in patients with idiopathic pulmonary fibrosis IPF is mainly limited by mechanical constrain of ventilation and high physiologic dead space. Oxygen enriched gas inhalation seems to increase ventilatory efficiency by reduction of dead space to tidal volume ratio (VD/VT) which probably mirrors improved pulmonary capillary flow and leads to longer physical tolerance at lower level of minute ventilation. The effect is noticeable at FIO2 that can be delivered in rehabilitation purposes or daily living activities.
In recent years, due to the occurrence of water shortage and drought problems, particularly in arid and semiarid regions of the world, new methods to reduce evaporation from the surface of dam reservoirs, lakes, and other waterfree surfaces are investigated. This study aimed to use hydrophobic bentonite to reduce water evaporation from water surfaces, on a laboratory scale, and field conditions for the first time. Bentonite initially became hydrophobic by stearic acid (SA). Under such conditions, hydrophobic bentonite floats on the surface of water and forms a thin coating layer. The produced hydrophobic bentonite had a contact angle of 150°, indicating its superhydrophobicity. Evaporation reduction was measured under laboratory and field conditions and it was compared to hexadecanol as the reference material. The results demonstrated that the hydrophobic bentonite efficiency under laboratory conditions was similar to that of hexadecanol and prevented water evaporation by 36%. However, under field conditions, hydrophobic bentonite and hexadecanol efficiencies were 40% and 23% to reduce evaporation for 30 days, respectively. In terms of stability, hexadecanol needed to be re-injected after three days, while hydrophobic bentonite was stable and remained on the surface for more than 100 days under laboratory conditions and for more than 15 days under field conditions without needing reinjection. This coverage with method can be used to reduce evaporation from lakes, tanks, and reservoirs of small dams.
Joints significantly reduce rock cohesion compared to unfractured rock, but the question is what effect the possible anisotropy of the shear strength of different types of rupture has on possible subsequent failure. Both natural samples of granodiorite with natural joints and fault surfaces and gypsum models have been tested on the Matest A129 Rock shear box apparatus. The shear strength of preexisting ruptures was measured under a fixed normal stress component. The anisotropy of the shear strength of the joints and fault surfaces reached more than 60 % of maximum strength, which is a very important value for solving structural loads. The shear strength was analyzed with polar plots. The pattern of the real joints typically showed a teardrop shape with one peak of strength in a certain direction and a minimum in the opposite direction. On the contrary, striated fault surfaces are characterized by two axial directions of minimal shear strength, i.e., longitudinal and transverse, and by two axial oblique directions with maximal shear strength, so the strength distribution in the polar graph has a four-cornered shape. The study showed that the anisotropy of the shear strength of various types of ruptures is their important feature.