The ExoMars program is an ESA–Roscosmos cooperation with some NASA contributions. ExoMars consists of two missions, one in 2016 and one in 2018. The 2016 mission includes an orbiting satellite ...dedicated to the study of atmospheric trace gases to acquire information on possible on-going geological or biological processes, and a European entry, descent, and landing demonstrator module (EDM) to achieve a successful soft landing on Mars. The orbiter can also provide data communication services for all surface missions landing on Mars until the end of 2022. The 2018 mission is planned to deliver a 300-kg-class rover and an instrumented landing platform to the Martian surface using a landing system developed by Roscosmos. The 2018 mission is to pursue one of the most outstanding questions of our time by attempting to establish whether life ever existed, or is still present, on Mars today. The article gives an overview of the ExoMars program.
Titan, Saturn's largest moon, is the only Solar System planetary body other than Earth with a thick nitrogen atmosphere. The Voyager spacecraft confirmed that methane was the second-most abundant ...atmospheric constituent in Titan's atmosphere, and revealed a rich organic chemistry, but its cameras could not see through the thick organic haze. After a seven-year interplanetary journey on board the Cassini orbiter, the Huygens probe was released on 25 December 2004. It reached the upper layer of Titan's atmosphere on 14 January and landed softly after a parachute descent of almost 2.5 hours. Here we report an overview of the Huygens mission, which enabled studies of the atmosphere and surface, including in situ sampling of the organic chemistry, and revealed an Earth-like landscape. The probe descended over the boundary between a bright icy terrain eroded by fluvial activity--probably due to methane-and a darker area that looked like a river- or lake-bed. Post-landing images showed centimetre-sized surface details.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The evolution of flavonoids under altered temperature and light conditions in the fruit zone was followed in Cabernet Sauvignon (
Vitis vinifera
L.) grapes during ripening. The study was conducted ...over two consecutive seasons in 2010/2011 and 2011/2012 comprising two main treatments in which the light quantity was manipulated in the bunch zone: (1) standard (STD) with no lateral shoot or leaf removal and (2) leaf removal west (LRW) treatment with leaf removal on the western side of the bunch zone. Furthermore, the light quality was altered by installing ultraviolet B-suppression sheets within the bunch zone in both seasons. Tannin evolution was dependent on the prevailing light quality/quantity and temperatures during berry development in a particular season. Grape seed tannin accumulation coincided with seed development and commenced at the early stages of berry development. Seed proanthocyanidin composition was not influenced by the treatments. The largest impact on proanthocyanidin accumulation and structure in the skin was due to seasonal variations highlighting the complex interaction between light quality and/or quantity across the two growing seasons and eventually the complex interaction with temperature. Flavonol accumulation was significantly influenced by the light quality, which is known to be the main abiotic driver of flavonol biosynthesis regulation. Anthocyanin concentration and content were largely dependent on the temperature and light quality in a particular season. Anthocyanin composition was altered by the season rather than the treatment.
Almost 40 years ago, WHO commissioned a report on screening from James Maxwell Glover Wilson, then Principal Medical Officer at the Ministry of Health in London, England, and Gunner Jungner, then ...Chief of the Clinical Chemistry Department of Sahlgren’s Hospital in Gothenburg, Sweden. The report
1
, published in 1968, was entitled:
Principles and practice of screening for disease
and it has since become a public health classic.
Folates (B9 vitamins) are essential cofactors in one-carbon metabolism. Since C1 transfer reactions are involved in synthesis of nucleic acids, proteins, lipids, and other biomolecules, as well as in ...epigenetic control, folates are vital for all living organisms. This work presents a complete study of a plant DHFR-TS (dihydrofolate reductase-thymidylate synthase) gene family that implements the penultimate step in folate biosynthesis. We demonstrate that one of the DHFR-TS isoforms (DHFR-TS3) operates as an inhibitor of its two homologs, thus regulating DHFR and TS activities and, as a consequence, folate abundance. In addition, a novel function of folate metabolism in plants is proposed, i.e., maintenance of the redox balance by contributing to NADPH production through the reaction catalyzed by methylenetetrahydrofolate dehydrogenase, thus allowing plants to cope with oxidative stress.
PURPOSE OF REVIEWThe use of dietary supplements in sports is widespread as athletes are continuously searching for strategies to increase performance at the highest level. Beta-alanine is such a ...supplement that became increasingly popular during the past years. This review examines the available evidence regarding the optimization of supplementation, the link between beta-alanine and exercise performance and the underlying ergogenic mechanism.
RECENT FINDINGSIt has been repeatedly demonstrated that chronic beta-alanine supplementation can augment intramuscular carnosine content. Yet, the factors that determine the loading process, as well as the mechanism by which this has an ergogenic effect, are still debated. On the basis of its biochemical properties, several functions are ascribed to carnosine, of which intramuscular pH buffer and calcium regulator are the most cited ones. In addition, carnosine has antiglycation and antioxidant properties, suggesting it could have a therapeutic potential.
SUMMARYOn the basis of the millimolar presence of carnosine in mammalian muscles, it must play a critical role in skeletal muscle physiology. The recent number of studies shows that this is related to an improved exercise homeostasis and excitation-contraction coupling. Recent developments have led to the optimization of the beta-alanine supplementation strategies to elevate muscle carnosine content, which are helpful in its application in sports and to potential future therapeutic applications.
Biofortification of staple crops could help to alleviate micronutrient deficiencies in humans. We show that folates in stored rice grains are unstable, which reduces the potential benefits of folate ...biofortification. We obtain folate concentrations that are up to 150 fold higher than those of wild-type rice by complexing folate to folate-binding proteins to improve folate stability, thereby enabling long-term storage of biofortified high-folate rice grains.
Despite the presumption of the beneficial effects of magnesium supplementation, little is known about the pharmacokinetics of different magnesium formulations. We aimed to investigate the value of ...two in vitro approaches to predict bioavailability of magnesium and to validate this in subsequent in vivo testing. In vitro assessment of 15 commercially available magnesium formulations was performed by means of a Simulator of the Human Intestinal Microbial Ecosystem (SHIME
) and by dissolution tests. Two magnesium formulations with contrasting bioavailability prediction from both in vitro tests (best vs. worst) were selected for in vivo testing in 30 subjects. In vivo bioavailability was compared following one acute ingestion by monitoring blood magnesium concentrations up to 6 h following intake. The in vitro tests showed a very wide variation in absorption and dissolution of the 15 magnesium products. In the in vivo testing, a significant different serum magnesium absorption profile was found up to 4 h following supplement ingestion for the two supplements with opposing in vitro test results. Moreover, maximal serum magnesium increase and total area under the curve were significantly different for both supplements (+6.2% vs. +4.6% and 6.87 vs. 0.31 mM.min, respectively). Collectively, poor bioaccessibility and bioavailability in the SHIME model clearly translated into poor dissolution and poor bioavailability in vivo. This provides a valid methodology for the prediction of in vivo bioavailability and effectiveness of micronutrients by specific in vitro approaches.
Carnosine, particularly present in fast-twitch fibers, was investigated in the quadriceps of patients with chronic obstructive pulmonary disease (COPD). Carnosine concentration was similar between ...patients with COPD and healthy controls but was 30% lower in patients with severe/very severe COPD, despite their high proportion of fast-twitch fibers, versus patients with mild/moderate COPD. As no oxidative/carbonyl stress markers or antioxidants were affected, the observed carnosine deficiency is thought to be a possible first sign of muscle redox balance abnormalities.
Oxidative/carbonyl stress is elevated in lower-limb muscles of patients with chronic obstructive pulmonary disease (COPD). Carnosine is a skeletal muscle antioxidant particularly present in fast-twitch fibers. The aims of the present study were to compare muscle carnosine, oxidative/carbonyl stress, antioxidants, and fiber characteristics between patients with COPD and healthy controls (HCs) and between patients after stratification for airflow limitation (mild/moderate vs. severe/very severe), as well as to investigate correlates of carnosine in patients with COPD. A vastus lateralis muscle biopsy was obtained from 40 patients with stable COPD and 20 age- and sex-matched HCs. Carnosine, oxidative/carbonyl stress, antioxidants, fiber characteristics, quadriceps strength and endurance (QE), V̇o
2
peak (incremental cycle test), and physical activity (PA) were determined. Patients with COPD had a similar carnosine concentration 4.16 mmol/kg wet weight (WW; SD = 1.93) to HCs 4.64 mmol/kg WW (SD = 1.71) and significantly higher percentage of fast-twitch fibers and lower QE, V̇o
2
peak, and PA versus HCs. Patients with severe/very severe COPD had a 31% lower carnosine concentration 3.24 mmol/kg WW (SD = 1.79); n = 15 versus patients with mild/moderate COPD 4.71 mmol/kg WW (SD = 1.83); n = 25; P = 0.02 and significantly lower V̇o
2
peak and PA versus patients with mild/moderate COPD. Carnosine correlated significantly with QE ( r
s
= 0.427), V̇o
2
peak ( r
s
= 0.334), PA ( r
s
= 0.379), and lung function parameters in patients with COPD. In conclusion, despite having the highest proportion of fast-twitch fibers, patients with severe/very severe COPD displayed a 31% lower muscle carnosine concentration compared with patients with mild/moderate COPD. As no other markers of oxidative/carbonyl stress or antioxidants were affected, the observed carnosine deficiency is thought to be a possible first sign of muscle redox balance abnormalities.
NEW & NOTEWORTHY Carnosine, particularly present in fast-twitch fibers, was investigated in the quadriceps of patients with chronic obstructive pulmonary disease (COPD). Carnosine concentration was similar between patients with COPD and healthy controls but was 31% lower in patients with severe/very severe COPD, despite their high proportion of fast-twitch fibers, versus patients with mild/moderate COPD. As no other markers of oxidative/carbonyl stress or antioxidants were affected, the observed carnosine deficiency is thought to be a possible first sign of muscle redox balance abnormalities.
Elliptic curve cryptography is a widely deployed technology for securing digital communication. It is the basis of many cryptographic primitives such as key agreement protocols, digital signatures, ...and zero-knowledge proofs. Fast elliptic curve cryptography relies on heavily optimised modular arithmetic operations, which are often tailored to specific micro-architectures. In this article, we study and evaluate optimisations of the popular elliptic curve Curve25519 for ARM processors. We specifically target the ARM NEON single instruction, multiple data (SIMD) architecture, which is a popular architecture for modern smartphones. We introduce a novel representation for 128-bit NEON SIMD vectors, optimised for SIMD parallelisation, to accelerate elliptic curve operations significantly. Leveraging this representation, we implement an extended twisted Edwards curve Curve25519 back-end within the popular Rust library "curve25519-dalek". We extensively evaluate our implementation across multiple ARM devices using both cryptographic benchmarks and the benchmark suite available for the Signal protocol. Our findings demonstrate a substantial back-end speed-up of at least 20% for ARM NEON, along with a noteworthy speed improvement of at least 15% for benchmarked Signal functions.
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