Bis(3-meth­oxy-6-methyl-2-pyrid­yl) ether

In the mol­ecule of the title compound, C14H16N2O3, the dihedral angle between the pyridyl rings is 87.74 (3)°. In the crystal structure, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into infinite zigzag chains

The Impact of L2 Learning on Cognitive Aging

It has become a multidisciplinary research area to overcome cognitive decline caused by aging. Many factors can affect cognitive aging and the influence of second language learning (L2 learning) cannot be ignored. The recent decade has witnessed much pathological, behavior and neuroimaging research that L2 experience may help maintain the cognitive function in the elderly, resist cognitive decline, and even delay the onset of Alzheimer\u27s disease (AD). This work is to review available literature concerned and elucidate the neural mechanisms under which L2 learning (training) may modify or sculpt the brain from perspectives of cognitive reserve, plasticity and overlapping networks. Future directions concerning length of learning, frequency of use, comparison with other cognitively stimulating activities are put forward so as to clarify the relationship between language experience and cognitive aging

A Transmissive X-ray Polarimeter Design For Hard X-ray Focusing Telescopes

The X-ray Timing and Polarization (XTP) is a mission concept for a future space borne X-ray observatory and is currently selected for early phase study. We present a new design of X-ray polarimeter based on the time projection gas chamber. The polarimeter, placed above the focal plane, has an additional rear window that allows hard X-rays to penetrate (a transmission of nearly 80% at 6 keV) through it and reach the detector on the focal plane. Such a design is to compensate the low detection efficiency of gas detectors, at a low cost of sensitivity, and can maximize the science return of multilayer hard X-ray telescopes without the risk of moving focal plane instruments. The sensitivity in terms of minimum detectable polarization, based on current instrument configuration, is expected to be 3% for a 1mCrab source given an observing time of 10^5 s. We present preliminary test results, including photoelectron tracks and modulation curves, using a test chamber and polarized X-ray sources in the lab

The impact of single nucleotide polymorphism in monomeric alpha-amylase inhibitor genes from wild emmer wheat, primarily from Israel and Golan

<p>Abstract</p> <p>Background</p> <p>Various enzyme inhibitors act on key insect gut digestive hydrolases, including alpha-amylases and proteinases. Alpha-amylase inhibitors have been widely investigated for their possible use in strengthening a plant's defense against insects that are highly dependent on starch as an energy source. We attempted to unravel the diversity of monomeric alpha-amylase inhibitor genes of Israeli and Golan Heights' wild emmer wheat with different ecological factors (e.g., geography, water, and temperature). Population methods that analyze the nature and frequency of allele diversity within a species and the codon analysis method (comparing patterns of synonymous and non-synonymous changes in protein coding sequences) were used to detect natural selection.</p> <p>Results</p> <p>Three hundred and forty-eight sequences encoding monomeric alpha-amylase inhibitors (WMAI) were obtained from 14 populations of wild emmer wheat. The frequency of SNPs in WMAI genes was 1 out of 16.3 bases, where 28 SNPs were detected in the coding sequence. The results of purifying and the positive selection hypothesis (p < 0.05) showed that the sequences of WMAI were contributed by both natural selection and co-evolution, which ensured conservation of protein function and inhibition against diverse insect amylases. The majority of amino acid substitutions occurred at the C-terminal (positive selection domain), which ensured the stability of WMAI. SNPs in this gene could be classified into several categories associated with water, temperature, and geographic factors, respectively.</p> <p>Conclusions</p> <p>Great diversity at the WMAI locus, both between and within populations, was detected in the populations of wild emmer wheat. It was revealed that WMAI were naturally selected for across populations by a ratio of dN/dS as expected. Ecological factors, singly or in combination, explained a significant proportion of the variations in the SNPs. A sharp genetic divergence over very short geographic distances compared to a small genetic divergence between large geographic distances also suggested that the SNPs were subjected to natural selection, and ecological factors had an important evolutionary role in polymorphisms at this locus. According to population and codon analysis, these results suggested that monomeric alpha-amylase inhibitors are adaptively selected under different environmental conditions.</p