Calculation of Carrier Doping-Induced Half-Metallicity, and Transformation of Easy Axis in Two-Dimensional MSi2N4 (M = Cr, Mn, Fe, and Co) Monolayers

We study the stability, electrical properties, and magnetic properties of MSi2N4 (M = Cr, Mn, Fe, and Co) monolayers based on the density functional theory.Comment: 10 figure

Evaluating and clustering retrosynthesis pathways with learned strategy

With recent advances in the computer-aided synthesis planning (CASP) powered by data science and machine learning, modern CASP programs can rapidly identify thousands of potential pathways for a given target molecule. However, the lack of a holistic pathway evaluation mechanism makes it challenging to systematically prioritize strategic pathways except for using some simple heuristics. Herein, we introduce a data-driven approach to evaluate the relative strategic levels of retrosynthesis pathways using a dynamic tree-structured long short-term memory (tree-LSTM) model. We first curated a retrosynthesis pathway database, containing 238k patent-extracted pathways along with ∼55 M artificial pathways generated from an open-source CASP program, ASKCOS. The tree-LSTM model was trained to differentiate patent-extracted and artificial pathways with the same target molecule in order to learn the strategic relationship among single-step reactions within the patent-extracted pathways. The model achieved a top-1 ranking accuracy of 79.1% to recognize patent-extracted pathways. In addition, the trained tree-LSTM model learned to encode pathway-level information into a representative latent vector, which can facilitate clustering similar pathways to help illustrate strategically diverse pathways generated from CASP programs

The Variation of Microbial Communities in a Depth Profile of Peat in the Gahai Lake Wetland Natural Conservation Area

<p>The Gahai Lake wetland natural conservation area in northwestern China includes peatland that has been accumulating over hundreds of years and is seldom disturbed by industry. Bacteria and archaea in peat soil, which is a reservoir for carbon and water, may influence its ecological function. The objective of this study was to obtain a clearer understanding of peat microbial ecology and its relationship to the environmental conditions of this area. Hence, the microbial community of the peatland ecosystem was investigated by sequencing bacterial and archaeal DNA extracted from samples collected at different peat depths. Results showed that in all samples the dominant bacterial phyla were <i>Proteobacteria</i> (relative abundance 0.39 ± 0.12) and <i>Chloroflexi</i> (0.16 ± 0.09), while the dominant archaeal phyla were Miscellaneous Crenarchaeotic Group (MCG) (0.62 ± 0.21) and <i>Euryarchaeota</i> (0.27 ± 0.16). The diversity and microbial community structure at deeper depths (90 and 120 cm below the peat surface) significantly differ from that at shallower depths (10, 30 and 50 cm deep). In contrast to the shallow layers, the deeper layers became more abundant in the bacterial phyla <i>Chloroflexi, Bacteroidetes</i>, Atribacteria, Aminicenantes, <i>Chlorobi</i>, TA06, Caldiserica and <i>Spirochaetae</i>; and in the archaeal phyla MCG and Miscellaneous Euryarchaeotic Group (MEG). This study revealed a significant shift in microbial community in peat between 50 cm and 90 cm deep, as probably influenced by the oxygen supply at different depths. Furthermore, new insights into the microbial taxa were obtained, thus providing a baseline for future studies of this peat ecosystem.</p

Circulating Tumor DNA: Less Invasive, More Representative Method to Unveil the Genomic Landscape of Newly Diagnosed Multiple Myeloma Than Bone Marrow Aspirates

Multiple myeloma (MM) is highly heterogenous and dynamic in its genomic abnormalities. Capturing a representative image of these alterations is essential in understanding the molecular pathogenesis and progression of the disease but was limited by single-site invasive bone marrow (BM) biopsy-based genomics studies. We compared the mutational landscapes of circulating tumor DNA (ctDNA) and BM in 82 patients with newly diagnosed MM. A 413-gene panel was used in the sequencing. Our results showed that more than 70% of MM patients showed one or more genes with somatic mutations and at least half of the mutated genes were shared between ctDNA and BM samples. Compared to the BM samples, ctDNA exhibited more types of driver mutations in the shared driver genes, higher numbers of uniquely mutated genes and subclonal clusters, more translocation-associated mutations, and higher frequencies of mutated genes enriched in the transcriptional regulation pathway. Multivariate Cox analysis showed that age, ctDNA mutations in the transcriptional regulation pathway and DNA repair pathway were independent predictors of progression-free survival (PFS). Our results demonstrated sequencing of ctDNA provides more thorough information on the genomic instability and is a potential representative biomarker for risk stratification and in newly diagnosed MM than bone marrow