dose responses
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Pharmacia ◽  
2021 ◽  
Vol 68 (4) ◽  
pp. 907-917
Author(s):  
Putu Sanna Yustiantara ◽  
Ni Kadek Warditiani ◽  
Pande Made Nova Armita Sari ◽  
Ni Luh Kade Arman Anita Dewi ◽  
Yan Ramona ◽  
...  

Antihyperglycemic activity of Ipomoea batatas (L.) leaves has been studied for years. As many naturally found varieties of such plant species have been used as herbal medicines, there is a need to establish a fingerprint biomarker standardization method. Our research combined TLC fingerprints and chemometric analysis to determine biomarkers in leaf ethanol extract of Ipomoea batatas (L.) (EIBL). We predicted the main constituents of anthocyanin glycosides and their acylated derivates in the leaf ethanol extract of such plants using ESI-MS. The EIBL that contained identified biomarkers has succeeded in providing an antihyperglycemic effect in experimental using STZ-induced rats. This study also found a linear correlation between doses of flavonoid derivates as antioxidant agents with their antihyperglycemic activities. Therefore, this biomarker information can be used as a model to predict the dose-responses of the antihyperglycemic activities produced by other leaf ethanol extracts of I. batatas.


2021 ◽  
Vol 22 (18) ◽  
pp. 9892
Author(s):  
Yanli Zhang ◽  
Yuanling Sun ◽  
Xiaojing Liu ◽  
Jiayin Deng ◽  
Jun Yao ◽  
...  

Stomatal regulation is crucial to reduce water consumption under drought conditions. Extracellular ATP (eATP) serves as a signaling agent in stomatal regulation; however, it is less known whether the eATP mediation of stomatal aperture is linked to apyrases (APYs), the principal enzymes that control the concentration of eATP. To clarify the role of APYs in stomatal control, PeAPY1 and PeAPY2 were isolated from Populus euphratica and transferred into Arabidopsis. Compared with the wild-type Arabidopsis and loss-of-function mutants (Atapy1 and Atapy2), PeAPY1- and PeAPY2-transgenic plants decreased stomatal aperture under mannitol treatment (200 mM, 2 h) and reduced water loss during air exposure (90 min). The role of apyrase in stomatal regulation resulted from its control in eATP-regulated stomatal movements and increased stomatal sensitivity to ABA. The bi-phasic dose-responses to applied nucleotides, i.e., the low ATP (0.3–1.0 mM)-promoted opening and high ATP (>2.0 mM)-promoted closure, were both restricted by P. euphratica apyrases. It is noteworthy that eATP at a low concentration (0.3 mM) counteracted ABA action in the regulation of stomatal aperture, while overexpression of PeAPY1 or PeAPY2 effectively diminished eATP promotion in opening, and consequently enhanced ABA action in closure. We postulate a speculative model of apyrase signaling in eATP- and ABA-regulated stomatal movements under drought.


2021 ◽  
Author(s):  
Mark A. Brockman ◽  
Francis M. Mwimanzi ◽  
Hope R. Lapointe ◽  
Yurou Sang ◽  
Olga Agafitei ◽  
...  

Background mRNA vaccines reduce COVID-19 incidence and severity, but the durability of vaccine-induced immune responses, particularly among the elderly, remains incompletely characterized. Methods Anti-spike RBD antibody titers, ACE2 competition and virus neutralizing activities were longitudinally assessed in 151 healthcare workers and older adults (overall aged 24-98 years) up to three months after vaccination. Results Older adults exhibited lower antibody responses after one and two vaccine doses for all measures. In multivariable analyses correcting for sociodemographic, chronic health and vaccine-related variables, age remained independently associated with all response outcomes. The number of chronic health conditions was additionally associated with lower binding antibody responses after two doses, and male sex with lower ACE2 competition activity after one dose. Responses waned universally at three months after the second dose, but binding antibodies, ACE2 competition and neutralizing activities remained significantly lower with age. Older adults also displayed reduced ability to block ACE2 binding by the Delta variant. Conclusions The humoral immune response to COVID-19 mRNA vaccines is significantly weaker with age, and universally wanes over time. This will likely reduce antibody-mediated protection against SARS-CoV-2 and the Delta variant as the pandemic progresses. Older adults may benefit from additional immunizations as a priority.


Author(s):  
Xianyao Zheng ◽  
Zhixiang Xu ◽  
Dimeng Zhao ◽  
Yu Luo ◽  
Chaochao Lai ◽  
...  

2021 ◽  
Vol 11 (16) ◽  
pp. 7221
Author(s):  
Andrzej Gasiorowski ◽  
Piotr Szajerski ◽  
Jose Francisco Benavente Cuevas

The phosphate glass samples doped with Tb2O3 oxide (general formula: P2O5-Al2O3-Na2O-Tb2O3) were synthesized and studied for usage in high-dose radiation dosimetry (for example, in high-activity nuclear waste disposals). The influence of terbium concentration on thermoluminescent (TL) signals was analyzed. TL properties of glasses were investigated using various experimental techniques such as direct measurements of TL response vs. radiation dose, Tmax–Tstop and VHR (various heating rate) methods, and glow curve deconvolution analysis. The thermoluminescence dosimetry (TLD) technique was used as the main investigation tool to study detectors’ dose responses. It has been proved that increasing the concentration of terbium oxide in glass matrices significantly increases the thermoluminescence yield of examined material. For the highest dose range (up to 35 kGy), the dependence of the integrated thermoluminescent signals vs. dose can be considered as a saturation-type curve. Additional preheating of samples improves linearity of signal vs. dose dependencies and leads to a decrease of the signal loss over time. All obtained data suggest that investigated material can be used in high-dose radiation dosimetry. Additional advantages of the investigated dosimetric system are its potential ability to re-use the same dosimeters multiple times and the fact that reading dosimeters only requires usage of a basic TL reader without any modifications.


2021 ◽  
pp. 1-24
Author(s):  
Zane Raudenbush ◽  
Steven J. Keeley ◽  
Cole Thompson ◽  
Mithila Jugulam

Abstract Carfentrazone-ethyl is one of few herbicides labeled for control of silvery-thread moss (STM) in golf course putting greens, but common use rates are up to three times higher than for broadleaf weeds. Our objective was to determine the efficacy of a single postemergence application of carfentrazone-ethyl for STM control in greenhouse and field dose response studies. In the greenhouse, carfentrazone-ethyl was applied at 0, 14, 28, 56, 112, and 224 g ai ha−1 to pots containing established STM and creeping bentgrass. Percent gametophyte injury was visually estimated at 14, 28, 49, and 77 d after treatment (DAT). Shoot viability was determined by excising shoots from treated pots and plating them in petri dishes containing sand. The 28 and 49 DAT ED90 (dose required to cause 90% gametophyte injury) were 26.8 and 54.3 g ha−1, respectively; both of these doses are substantially lower than the label rates for long- and short-term control, respectively. All doses reduced the viability of transplanted shoots at 10 DAT compared to untreated STM; however, regrowth occurred in all petri dishes by 17 DAT. Field studies were initiated in Manhattan, Kansas and San Luis Obispo, California to corroborate greenhouse results. Averaged across locations, carfentrazone-ethyl applied at 56 and 112 g ha−1 caused 76% and 84% STM injury at 14 DAT, but quickly reduced to 45% and 48% STM injury by 28 DAT, respectively. In greenhouse and field studies, STM recovery did not occur until after 2 wk after treatment (WAT), which indicates the label-stipulated application interval of 2 wk is too short. Our research suggests 56 g ha−1 can provide similar burndown control of STM as compared to the highest label rate (112 g ha−1), and turfgrass managers should consider extending the reapplication interval to 3 or 4 wk when moss recovery is observed.


2021 ◽  
Vol 03 (02) ◽  
pp. 28-35
Author(s):  
Noor T. HAMDAN

Mushrooms are food traditionally consumed in Asia, Europe and America. They are being studied for medicinal benefits. Extensive studies have shown that Agaricus brasiliensis mushroom used as a medical productto combat cancers. Our data reveal that the determined inhibitory concentration fifty(IC50) values were observed maximum dose responses (IC50) of WRL68 andAsPC-1 cancer cells reported of 172.6 µg/ml and 158.2 µg/ml respectively at 2.23 and 2.1 µg/ml ethanolic mushroom concentrations. The highly cytotoxic activity of the extract on growth inhibition AsPC-1 and WRL68were generally observed 97.9% and 95% at extract concentrations of 25 µg/ml and 50µg/ml respectively. Finally, Phytochemical profile of Agaricus brasiliensis mushroom extract found to beflavonoids, glycosides, saponins, phenols,alkaloids, tannins.The extracts of Agaricus brasiliensiswas tested throughGas Chromatography-Mass(GC-MS). There were five different compounds analyzed from the extracts of Agaricus brasiliensis. The compounds in the ethanolic extract of A. brasiliensis mushroom were comprised mostly of Acetic acid ethyl ester(38.39%),followed by(3-Methyl-oxiran-2-yl)-methanol (34.71%), Chlorbromuron (22.86%), n-Hexadecanoic acid (3.85%) and Heptane, 1-(1-butenyloxy) (0.19%). However, no studies were done using Agaricus brasiliensismushroom extract against WRL68 and AsPC-1 human cell lines. Therefore, the anticancer efficiency of Agaricus brasiliensis mushroom on human embryonic liver WRL68 andhuman pancreatic AsPC-1 cancer cellstherapy is being reported for the first time in the current study.


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