97 research outputs found
Structural design using a parallel sequential approximate optimization
In this paper, a parallel sampling strategy dedicated to SAO is proposed to enhance
the competence of exploration and convergence simultaneously in the optimization process. In
the parallel sampling procedure, new sampling points are identified in the pareto front of the
multi-objective optimization problem, which is solved with the Normal constraint (NC) method.
The objectives of the optimization problem are the two indices to represent the competence of
exploration and convergence, and the sampled points will be evaluated by the true model in a
parallel way. Furthermore, the proposed methodology is evaluated on two benchmark tests.
Compared to other optimization algorithms, the PSAO algorithm yields equivalent or better
objective values while the number of optimization iterations required to find the same global
optima is reduced by multiple orders of magnitude, which substantially reduce the computing
costs in the tested structural design optimization tasks, highlighting the applicability of the
PSAO structural design optimization problems
A single nucleotide polymorphism possibly associated with fat deposition is methylated in the bovine TFAM promoter
Resting-state functional connectivity changes within the default mode network and the salience network after antipsychotic treatment in early-phase schizophrenia
OBJECTIVE: Abnormal resting-state functional connectivity (FC), particularly in the default mode network (DMN) and the salience network (SN), has been reported in schizophrenia, but little is known about the effects of antipsychotics on these networks. The purpose of this study was to examine the effects of atypical antipsychotics on DMN and SN and the relationship between these effects and symptom improvement in patients with schizophrenia. METHODS: This was a prospective study of 33 patients diagnosed with schizophrenia and treated with antipsychotics at Shanghai Mental Health Center. Thirty-three healthy controls matched for age and gender were recruited. All subjects underwent functional magnetic resonance imaging (fMRI). Healthy controls were scanned only once; patients were scanned before and after 6-8 weeks of treatment. RESULTS: In the DMN, the patients exhibited increased FC after treatment in the right superior temporal gyrus, right medial frontal gyrus, and left superior frontal gyrus and decreased FC in the right posterior cingulate/precuneus (P\u3c0.005). In the SN, the patients exhibited decreased FC in the right cerebellum anterior lobe and left insula (P\u3c0.005). The FC in the right posterior cingulate/precuneus in the DMN negatively correlated with the difference between the Clinical Global Impression (CGI) score pre/post-treatment (r=-0.564, P=0.023) and negative trends with the difference in the Positive and Negative Syndrome Scale (PANSS) total score pre/post-treatment (r=-0.475, P=0.063) and the difference in PANSS-positive symptom scores (r=-0.481, P=0.060). CONCLUSION: These findings suggest that atypical antipsychotics could regulate the FC of certain key brain regions within the DMN in early-phase schizophrenia, which might be related to symptom improvement. However, the effects of atypical antipsychotics on SN are less clear
Significance of Photosynthetic Characters in the Evolution of Asian Gnetum (Gnetales)
Gnetum is a genus in the Gnetales that has a unique but ambiguous placement within seed plant phylogeny. Previous studies have shown that Gnetum has lower values of photosynthetic characters than those of other seed plants, but few Gnetum species have been studied, and those that have been studied are restricted to narrow taxonomic and geographic ranges. In addition, the mechanism underlying the lower values of photosynthetic characters in Gnetum remains poorly understood. Here, we investigated the photosynthetic characters of a Chinese lianoid species, i.e., Gnetum parvifolium, and co-occurring woody angiosperms growing in the wild, as well as seedlings of five Chinese Gnetum species cultivated in a greenhouse. The five Gnetum species had considerably lower values for photosynthesis parameters (net photosynthetic rate, transpiration rate, intercellular CO2 concentration, and stomatal conductance) than those of other seed plant representatives. Interrelated analyses revealed that the low photosynthetic capacity may be an intrinsic property of Gnetum, and may be associated with its evolutionary history. Comparison of the chloroplast genomes (cpDNAs) of Gnetum with those of other seed plant representatives revealed that 17 coding genes are absent from the cpDNAs of all species of Gnetum. This lack of multiple functional genes from the cpDNAs probably leads to the low photosynthetic rates of Gnetum. Our results provide a new perspective on the evolutionary history of the Gnetales, and on the ecophysiological and genomic attributes of tropical biomes in general. These results could also be useful for the breeding and cultivation of Gnetum
Transcriptome differences between 20- and 3,000-year-old Platycladus orientalis reveal that ROS are involved in senescence regulation
Background: Platycladus orientalis has an extremely long life span of
several thousands of years, attracting great interests in the
mechanisms involved in such successful senescence regulation and
resistance at physiological and molecular levels. Results: The levels
of reactive oxygen species (ROS) were higher in 3,000-year-old than in
20-year-old P. orientalis, and the activities of GR and GSH
demonstrated the same trend. We produced and analyzed massive sequence
information from pooled samples of P. orientalis through transcriptome
sequencing, which generated 51,664 unigenes with an average length of
475 bp. We then used RNA-seq analysis to obtain a high-resolution
age\u2013course profile of gene expression in 20- and 3,000-year-old
P. orientalis individuals. Totally, 106 differentially expressed genes
were obtained, of which 47 genes were downregulated and 59 upregulated
in the old tree. These genes were involved in transcription factors,
hormone-related responses, ROS scavengers, senescence-related
responses, stress response, and defense and possibly play crucial roles
in tackling various stresses in the 3,000-year-old P. orientalis during
its life time. The expression patterns of genes related to ROS
homeostasis further indicated that the high ability of ROS scavenging
could be helpful for the 3,000-year-old P. orientalis to resist
senescence. Conclusions: This study provides a foundation for the
elucidation of senescence resistance through molecular studies and the
discovery of useful genes in P. orientalis
Oxidation of Alpha-Ketoglutarate Is Required for Reductive Carboxylation in Cancer Cells with Mitochondrial Defects
SummaryMammalian cells generate citrate by decarboxylating pyruvate in the mitochondria to supply the tricarboxylic acid (TCA) cycle. In contrast, hypoxia and other impairments of mitochondrial function induce an alternative pathway that produces citrate by reductively carboxylating α-ketoglutarate (AKG) via NADPH-dependent isocitrate dehydrogenase (IDH). It is unknown how cells generate reducing equivalents necessary to supply reductive carboxylation in the setting of mitochondrial impairment. Here, we identified shared metabolic features in cells using reductive carboxylation. Paradoxically, reductive carboxylation was accompanied by concomitant AKG oxidation in the TCA cycle. Inhibiting AKG oxidation decreased reducing equivalent availability and suppressed reductive carboxylation. Interrupting transfer of reducing equivalents from NADH to NADPH by nicotinamide nucleotide transhydrogenase increased NADH abundance and decreased NADPH abundance while suppressing reductive carboxylation. The data demonstrate that reductive carboxylation requires bidirectional AKG metabolism along oxidative and reductive pathways, with the oxidative pathway producing reducing equivalents used to operate IDH in reverse
Metabolic profiling reveals key metabolites regulating adventitious root formation in ancient Platycladus orientalis cuttings
Platycladus orientalis, a common horticultural tree species, has an extremely long life span and forms a graceful canopy. Its branches, leaves, and cones have been used in traditional Chinese medicine. However, difficulty in rooting is the main limiting factor for the conservation of germplasm resources. This study shows that the rooting rates and root numbers of cuttings were significantly reduced in ancient P. orientalis donors compared to 5-year-old P. orientalis donors. The contents of differentially accumulated metabolites (DAMs) in phenylpropanoid (caffeic acid and coniferyl alcohol) and flavonoid biosynthesis (cinnamoyl-CoA and isoliquiritigenin) pathways increased significantly in cuttings propagated from ancient P. orientalis donors compared to 5-year-old P. orientalis donors during adventitious root (AR) formation. These DAMs may prevent the ancient P. orientalis cuttings from rooting, and gradual lignification of callus was one of the main reasons for the failed rooting of ancient P. orientalis cuttings. The rooting rates of ancient P. orientalis cuttings were improved by wounding the callus to identify wounding-induced rooting-promoting metabolites. After wounding, the contents of DAMs in zeatin (5′-methylthioadenosine, cis-zeatin-O-glucoside, and adenine) and aminoacyl-tRNA biosynthesis (l-glutamine, l-histidine, l-isoleucine, l-leucine, and l-arginine) pathways increased, which might promote cell division and provided energy for the rooting process. The findings of our study suggest that breaking down the lignification of callus via wounding can eventually improve the rooting rates of ancient P. orientalis cuttings, which provides a new solution for cuttings of other difficult-to-root horticultural and woody plants
Patterns of Childhood Trauma and Psychological Distress among Injecting Heroin Users in China
Background: Childhood trauma has been reported as a possible cause of future substance abuse in some countries. This study reports the prevalence of childhood trauma and examines its association with psychological distress among injecting drug users from mainland China. Methodology: The study was conducted in three government-operated drug rehabilitation facilities in Shanghai, China in 2007. The Early Trauma Inventory Self Report-Short Form (ETISR-SF) was used to evaluate 4 types (general, emotional, physical and sexual) and severity of childhood trauma, and the Symptom Checklist-90-Revised (SCL-90-R) to evaluate psychological distress. Principal Findings: Among 341 injecting drug users who completed the study, about 80 % reported one or more types o
The complete chloroplast genome of Ulmus parvifolia, an important landscaping tree
Ulmus parvifolia is a promising tree species for landscaping. In this study, the complete genome of U. parvifolia was reported using next-generation sequencing technology. The chloroplast genome was a circular double-stranded DNA molecule with 159,182 bp in length. It contained a large single copy (LSC) region of 87,838 bp, a small single copy (SSC) region of 18,750 bp, and two inverted repeat (IRa and IRb) regions of 26,297 bp each, which exhibited a typical quadripartite structure. A total of 133 genes were identified, including 84 protein-coding genes, 41 tRNA genes, and eight rRNA genes. The overall GC content in the chloroplast genome was 35.59%. Phylogenetic analysis indicated that U. parvifolia, as a representative of Sect. Microptelea within the Ulmus genus, is sister to the species of Sect. Ulmus
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