Archaeal diversity and abundance within different layers of summer sea-ice and seawater from Prydz Bay, Antarctica

Fluorescence in-situ hybridization (FISH) and 16S rRNA gene clone library analyses were used to determine the abundance and diversity of archaea in Prydz Bay, Antarctica. Correlation analysis was also performed to assess links between physicochemical parameters and archaeal abundance and diversity within the sea-ice. Samples of sea-ice and seawater were collected during the 26th Chinese National Antarctic Research Expedition. The results of FISH showed that archaea were relatively abundant within the top layer of the sea-ice, and correlation analysis suggested that the concentration of NH4+ might be one of the main factors underlying this distribution pattern. However, using 16S rRNA gene libraries, archaea were not detected in the top and middle layers of the sea-ice. All archaeal clones obtained from the bottom layer of the sea-ice were grouped into the Marine Group I Crenarchaeota while the archaeal clones from seawater were assigned to Marine Group I Crenarchaeota, Marine Group II Euryarchaeota, and Marine Group III Euryarchaeota. Overall, the findings of this study showed that the diversity of archaea in the sea-ice in Prydz Bay was low

All-Electrical Skyrmionic Bits in a Chiral Magnetic Tunnel Junction

Topological spin textures such as magnetic skyrmions hold considerable promise as robust, nanometre-scale, mobile bits for sustainable computing. A longstanding roadblock to unleashing their potential is the absence of a device enabling deterministic electrical readout of individual spin textures. Here we present the wafer-scale realization of a nanoscale chiral magnetic tunnel junction (MTJ) hosting a single, ambient skyrmion. Using a suite of electrical and multi-modal imaging techniques, we show that the MTJ nucleates skyrmions of fixed polarity, whose large readout signal - 20-70% relative to uniform states - corresponds directly to skyrmion size. Further, the MTJ exploits complementary mechanisms to stabilize distinctly sized skyrmions at zero field, thereby realizing three nonvolatile electrical states. Crucially, it can write and delete skyrmions using current densities 1,000 times lower than state-of-the-art. These results provide a platform to incorporate readout and manipulation of skyrmionic bits across myriad device architectures, and a springboard to harness chiral spin textures for multi-bit memory and unconventional computing.Comment: 8 pages, 5 figure

Altered Brain Function in Treatment-Resistant and Non-treatment-resistant Depression Patients: A Resting-State Functional Magnetic Resonance Imaging Study

ObjectiveIn this study, we used amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) to observe differences in local brain functional activity and its characteristics in patients with treatment-resistant depression (TRD) and non-treatment-resistant depression (nTRD), and to explore the correlation between areas of abnormal brain functional activity and clinical symptoms.MethodThirty-seven patients with TRD, 36 patients with nTRD, and 35 healthy controls (HCs) were included in resting-state fMRI scans. ALFF and ReHo were used for image analysis and further correlation between abnormal brain regions and clinical symptoms were analyzed.ResultsANOVA revealed that the significantly different brain regions of ALFF and ReHo among the three groups were mainly concentrated in the frontal and temporal lobes. Compared with the nTRD group, the TRD group had decreased ALFF in the left/right inferior frontal triangular gyrus, left middle temporal gyrus, left cuneus and bilateral posterior lobes of the cerebellum, and increased ALFF in the left middle frontal gyrus and right superior temporal gyrus, and the TRD group had decreased ReHo in the left/right inferior frontal triangular gyrus, left middle temporal gyrus, and increased ReHo in the right superior frontal gyrus. Compared with the HC group, the TRD group had decreased ALFF/ReHo in both the right inferior frontal triangular gyrus and the left middle temporal gyrus. Pearson correlation analysis showed that both ALFF and ReHo values in these abnormal brain regions were positively correlated with HAMD-17 scores (P < 0.05).ConclusionAlthough the clinical symptoms were similar in the TRD and nTRD groups, abnormal neurological functional activity were present in some of the same brain regions. Compared with the nTRD group, ALFF and ReHo showed a wider range of brain area alterations and more complex neuropathological mechanisms in the TRD group, especially in the inferior frontal triangular gyrus of the frontal lobe and the middle temporal gyrus of the temporal lobe

Differential gene expression between wild-type and Gulo-deficient mice supplied with vitamin C

The aim of this study was to test the hypothesis that hepatic vitamin C (VC) levels in VC deficient mice rescued with high doses of VC supplements still do not reach the optimal levels present in wild-type mice. For this, we used a mouse scurvy model (sfx) in which the L-gulonolactone oxidase gene (Gulo) is deleted. Six age- (6 weeks old) and gender- (female) matched wild-type (WT) and sfx mice (rescued by administering 500 mg of VC/L) were used as the control (WT) and treatment (MT) groups (n = 3 for each group), respectively. Total hepatic RNA was used in triplicate microarray assays for each group. EDGE software was used to identify differentially expressed genes and transcriptomic analysis was used to assess the potential genetic regulation of Gulo gene expression. Hepatic VC concentrations in MT mice were significantly lower than in WT mice, even though there were no morphological differences between the two groups. In MT mice, 269 differentially expressed transcripts were detected (≥ twice the difference between MT and WT mice), including 107 up-regulated and 162 down-regulated genes. These differentially expressed genes included stress-related and exclusively/predominantly hepatocyte genes. Transcriptomic analysis identified a major locus on chromosome 18 that regulates Gulo expression. Since three relevant oxidative genes are located within the critical region of this locus we suspect that they are involved in the down-regulation of oxidative activity in sfx mice

Design and Analysis of a 5-Degree of Freedom (DOF) Hybrid Three-Nozzle 3D Printer for Wood Fiber Gel Material

Wood is an organic renewable natural resource. Cellulose, hemicellulose and lignin in wood are used in tissue engineering, biomedicine and other fields because of their good properties. This paper reported that the possibility of wood fiber gel material molding and the preparing of gel material were researched based on the wood fiber gel material as a 3D printing material. A five-degree of freedom hybrid three nozzle 3D printer was designed. The structural analysis, static analysis, modal analysis and transient dynamic analysis of 3D printers were researched, and the theoretical basis of the 3D printer was confirmed as correct and structurally sound. The results showed that the 5-DOF hybrid 3-nozzle 3D printer achieved the 3D printing of wood fiber gel material and that the printer is capable of multi-material printing and multi-degree-of-freedom printing

Slow Recovery of Major Soil Nutrient Pools during Reclamation in a Sub-Alpine Copper Mine Area, Southeastern Edge of the Tibetan Plateau, Sichuan Province, SW China

Improvement of soil nutrients is crucial for the long-term development and stability of restored ecosystems in mine areas. However, knowledge about the variation in soil nutrients and their influencing factors during the reclamation of sub-alpine metal mine soil is still scarce. We assess the status of soil organic carbon (SOC), total nitrogen (TN), N fractions, total phosphorus (TP), and available P in reclaimed soil at a copper mine site (2702 m above sea level) in the southeastern edge of the Tibetan Plateau, southwest China. The mine area had been reclaimed by distributing stockpiled topsoil (~15 cm) in 2008, sowing seeds of ryegrass (Lolium perenne L.) in 2009, and planting seedlings of A. ferdinandi-coburgii and Rosa omeiensis f. pteracantha in 2010. We found that, eight years after the reclamation, although the concentrations of SOC (24.3 g kg−1) and TN (2.21 g kg−1) in the reclaimed soil increased by 25% and 29% compared with the stockpiled topsoil, respectively, they only accounted for about half of the levels in the undisturbed topsoil. In contrast, the concentration of TP (498–570 mg kg−1) did not significantly change between the reclaimed and stockpiled topsoil. The concentrations of NH4-N (30.1 g kg−1), NO3-N (17.2 g kg−1), and available P (11.1 mg kg−1) in the reclaimed soil were 2.2, 1.3, and 1.6 times the levels in stockpiled topsoil, respectively, but still lower than those in undisturbed soil. The concentrations of microbial C, N, and P in the reclaimed soil had a similar variation pattern to the available nutrients. The soil C:P and N:P ratios and microbial biomass C:P and N:P ratios in the reclaimed soil were significantly lower than the levels in the undisturbed forest soil. The average accumulation rates of SOC and TN in the reclaimed soil were 85.3 and 11.4 g m−2 year−1, respectively. The rates are much lower than those of reclaimed mine soils with similar reclaim duration but better climate conditions. Relatively slow development of vegetation and soil microorganisms and leaching due to a freeze–thaw cycle controlled by the sub-alpine climate are likely responsible for the slow recovery of soil SOC and TN