amplifying effect
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Author(s):  
Danièle Klett ◽  
Yves Combarnous

IIn previous studies, we had shown the synergistic effect of 10-5 M forskolin (FSK) on the detection threshold of the cyclic AMP response to Luteinizing Hormones (LH) and Chorionic Gonadotropins (CG) from various species in the mouse Leydig Tumor cell (mLTC) cell line. Indepedently, we had started to study the effect of 10-12 – 10-6 M OXT also on the cyclic AMP response to LH and CG preparations on these same cells and found an amplifying effect on the luminescence response caused by gonadotropins. The aim was then to explore the effects of 10-12 – 10-6 M OXT on the gonadotropin-induced cAMP response, in the presence or absence of 10 µM FSK to optimize the assay down to a sensitivity compatible with the detection of the circulating concentrations of these hormones in various species. Finally the optimization relies on three independent phenomena: 1/ the inhibition of nucleotide phosphodiesterase by IBMX to avoid cAMP degradation, 2/ the strong synergy of 10 µM forskolin with low concentrations of LH or CG during the 1-hour luminescence measurement and, 3/ the stimulatory effect of 10-8M oxytocin on the amplitude of transfected cAMP-sensitive luciferase response. By doing this, the detectable concentrations are at the 1-10 pg/well (pM range) for the LHs and CGs from various species. The bioactivities of circulating LHs and CGs in blood or urine are therefore expected to be measurable in 10µL-plasma samples from mammalian species and maybe others.


2021 ◽  
Vol 17 (5) ◽  
pp. 2119-2137
Author(s):  
Laura Crick ◽  
Andrea Burke ◽  
William Hutchison ◽  
Mika Kohno ◽  
Kathryn A. Moore ◽  
...  

Abstract. The ∼74 ka Toba eruption was one of the largest volcanic events of the Quaternary. There is much interest in determining the impact of such a large event, particularly on the climate and hominid populations at the time. Although the Toba eruption has been identified in both land and marine archives as the Youngest Toba Tuff, its precise place in the ice core record is ambiguous. Several volcanic sulfate signals have been identified in both Antarctic and Greenland ice cores and span the Toba eruption 40Ar/39Ar age uncertainty. Here, we measure sulfur isotope compositions in Antarctic ice samples from the Dome C (EDC) and Dronning Maud Land (EDML) ice cores at high temporal resolution across 11 of these potential Toba sulfate peaks to identify candidates with sulfur mass-independent fractionation (S-MIF), indicative of an eruption whose plume reached altitudes at or above the stratospheric ozone layer. Using this method, we identify several candidate sulfate peaks that contain stratospheric sulfur. We further narrow down potential candidates based on the isotope signatures by identifying sulfate peaks that are due to a volcanic event at tropical latitudes. In one of these sulfate peaks at 73.67 ka, we find the largest ever reported magnitude of S-MIF in volcanic sulfate in polar ice, with a Δ33S value of −4.75 ‰. As there is a positive correlation between the magnitude of the S-MIF signal recorded in ice cores and eruptive plume height, this could be a likely candidate for the Toba super-eruption, with a plume top height in excess of 45 km. These results support the 73.7±0.3 ka (1σ) 40Ar/39Ar age estimate for the eruption, with ice core ages of our candidates with the largest magnitude S-MIF at 73.67 and 73.74 ka. Finally, since these candidate eruptions occurred on the transition into Greenland Stadial 20, the relative timing suggests that Toba was not the trigger for the large Northern Hemisphere cooling at this time although we cannot rule out an amplifying effect.


2021 ◽  
Vol 8 (3) ◽  
pp. 199-216
Author(s):  
Adel Razek

Different up-to-date utilizations have found several benefits in condensing the size of autonomous robots. Miniature traveling wave piezoelectric robots have proven to be appropriate for many of these applications. The principles of locomotion embraced in these robots are mainly inspired by natural biological locomotion and could be categorized by their movement through a specific medium. In this article, after having highlighted the amplifying effect of piezoelectric actuators generating the locomotion necessary for robotic requests, we will review the different types of such locomotion. Next, we will discuss the traveling wave piezoelectric resonant robots. Succeeding, we will look at the operation and usages of piezoelectric beam and plate robots. Finally, we will discuss the modeling aspects implicated in these robots and more generally, the modeling of piezoelectric patches stuck on thin structures. Keywords: piezoelectric, miniature, travelling-wave, locomotion, beam and plate robots


2021 ◽  
Vol 5 ◽  
Author(s):  
Steven R. McGreevy ◽  
Norie Tamura ◽  
Mai Kobayashi ◽  
Simona Zollet ◽  
Kazumasa Hitaka ◽  
...  

Individual agroecological farms can act as lighthouses to amplify the uptake of agroecological principles and practices by other farmers. Amplification is critical for the upscaling of agroecological production and socio-political projects emphasizing farmer sovereignty and solidarity. However, territories are contested spaces with historical, social, cultural, and economic contexts that can present challenges to the effectiveness of farmer lighthouses in catalyzing localized agrarian change. We explore these amplification dynamics through fieldwork in a particular region of Japan employing interviews and data derived from an assessment of nine farms using ten amplification indicators. The indicators include social organization, participation in networks, community leadership, and degrees of dependency on policies or markets among others, as well as degree of adoption of on-farm agroecological practices, all of which capture farmer lighthouses' potential to amplify territorial upscaling. At the same time, we trace the historical development of a previous generation of Japanese farmer lighthouses practicing organic agriculture in alignment with agroecological principles that experienced, to varying degrees, push-back, co-option, and successful territorialization in rural communities. We find that many of the same social and cultural territorial dynamics are still influential today and affecting the amplifying effect of agroecological farmer lighthouses, but also find examples of new clustering around lighthouses that take advantage of both the historical vestiges of the previous generation's efforts as well as contemporary shifts in practice and agrarian orientation. This research calls for a detailed dissection of the dynamic and contrasting processes of agroecological territorialization and the ways in which diverse contexts shape agroecological upscaling.


2021 ◽  
Vol 12 ◽  
Author(s):  
Akram Tayanloo-Beik ◽  
Peyvand Parhizkar Roudsari ◽  
Mostafa Rezaei-Tavirani ◽  
Mahmood Biglar ◽  
Ozra Tabatabaei-Malazy ◽  
...  

Diabetes and heart failure, as important global issues, cause substantial expenses to countries and medical systems because of the morbidity and mortality rates. Most people with diabetes suffer from type 2 diabetes, which has an amplifying effect on the prevalence and severity of many health problems such as stroke, neuropathy, retinopathy, kidney injuries, and cardiovascular disease. Type 2 diabetes is one of the cornerstones of heart failure, another health epidemic, with 44% prevalence. Therefore, finding and targeting specific molecular and cellular pathways involved in the pathophysiology of each disease, either in diagnosis or treatment, will be beneficial. For diabetic cardiomyopathy, there are several mechanisms through which clinical heart failure is developed; oxidative stress with mediation of reactive oxygen species (ROS), reduced myocardial perfusion due to endothelial dysfunction, autonomic dysfunction, and metabolic changes, such as impaired glucose levels caused by insulin resistance, are the four main mechanisms. In the field of oxidative stress, advanced glycation end products (AGEs), protein kinase C (PKC), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) are the key mediators that new omics-driven methods can target. Besides, diabetes can affect myocardial function by impairing calcium (Ca) homeostasis, the mechanism in which reduced protein phosphatase 1 (PP1), sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2a (SERCA2a), and phosphorylated SERCA2a expressions are the main effectors. This article reviewed the recent omics-driven discoveries in the diagnosis and treatment of type 2 diabetes and heart failure with focus on the common molecular mechanisms.


2021 ◽  
Vol 9 ◽  
Author(s):  
Yonghui Zhai ◽  
Dayang Jiang ◽  
Giray Gozgor ◽  
Eunho Cho

Using the COVID-19 database of Johns Hopkins University, this study examines the determinants of the case fatality rate of COVID-19. We consider various potential determinants of the mortality risk of COVID-19 in 120 countries. The Ordinary Least Squares (OLS) and the Kernel-based Regularized Least Squares (KRLS) estimations show that internal and external conflicts are positively related to the case fatality rates. This evidence is robust to the exclusion of countries across different regions. Thus, the evidence indicates that conflict may explain significant differences in the case fatality rate of COVID-19 across countries.


2021 ◽  
Vol 118 (30) ◽  
pp. e2026290118
Author(s):  
Paulo Ceppi ◽  
Peer Nowack

Global warming drives changes in Earth’s cloud cover, which, in turn, may amplify or dampen climate change. This “cloud feedback” is the single most important cause of uncertainty in Equilibrium Climate Sensitivity (ECS)—the equilibrium global warming following a doubling of atmospheric carbon dioxide. Using data from Earth observations and climate model simulations, we here develop a statistical learning analysis of how clouds respond to changes in the environment. We show that global cloud feedback is dominated by the sensitivity of clouds to surface temperature and tropospheric stability. Considering changes in just these two factors, we are able to constrain global cloud feedback to 0.43 ± 0.35 W⋅m−2⋅K−1 (90% confidence), implying a robustly amplifying effect of clouds on global warming and only a 0.5% chance of ECS below 2 K. We thus anticipate that our approach will enable tighter constraints on climate change projections, including its manifold socioeconomic and ecological impacts.


Author(s):  
L. A. Leonova ◽  
◽  
L. V. Ostankova ◽  
M. O. Bondarovych ◽  
M. V. Ostankov ◽  
...  

One of the urgent problems of modern dermatology is atopic dermatitis (AD), which has multifactorial pathogenesis, the significant prevalence of the disease, the increased frequency of the complicated course, the lack of radical methods of therapy. The expediency to use cryopreserved fetal liver cells (cFLCs) for the treatment of AD is proved by a wide range of produced by them biologically active substances with immunomodulatory and anti-inflammatory activity. Disclosure of the mechanisms of the therapeutic action of biotherapeutic drugs in AD provides for the determination of the state of the cellular and humoral links of the immune system (IS). In this regard, the aim of the work was to assess the effectiveness of cFLCs injection by characteristic clinical and immunological parameters in rats with AD. The results of the study in rats with AD revealed disorders in the IS, manifested in a decrease in the total number of T-lymphocytes and their subpopulations in the spleen, in an increase in the level of circulating immune complexes and a number of immunoglobulins in the blood serum, and in a decrease in the phagocytic activity of the peritoneal cavity cells. Therapy with cFLCs, in contrast to the standard treatment with prednisolone, significantly improves the therapeutic effect, which is demonstrated by the restoration of the parameters of the cellular and humoral links of the immune system in animals with AD. The amplifying effect of the combined use of cFLCs and prednisolone on a number of parameters of the immune system in AD was shown.


2021 ◽  
pp. 103370
Author(s):  
Simon Büchler ◽  
Maximilian v. Ehrlich ◽  
Olivier Schöni

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