Robust distance correlation for variable screening

High-dimensional data are commonly seen in modern statistical applications, variable selection methods play indispensable roles in identifying the critical features for scientific discoveries. Traditional best subset selection methods are computationally intractable with a large number of features, while regularization methods such as Lasso, SCAD and their variants perform poorly in ultrahigh-dimensional data due to low computational efficiency and unstable algorithm. Sure screening methods have become popular alternatives by first rapidly reducing the dimension using simple measures such as marginal correlation then applying any regularization methods. A number of screening methods for different models or problems have been developed, however, none of the methods have targeted at data with heavy tailedness, which is another important characteristics of modern big data. In this paper, we propose a robust distance correlation (``RDC'') based sure screening method to perform screening in ultrahigh-dimensional regression with heavy-tailed data. The proposed method shares the same good properties as the original model-free distance correlation based screening while has additional merit of robustly estimating the distance correlation when data is heavy-tailed and improves the model selection performance in screening. We conducted extensive simulations under different scenarios of heavy tailedness to demonstrate the advantage of our proposed procedure as compared to other existing model-based or model-free screening procedures with improved feature selection and prediction performance. We also applied the method to high-dimensional heavy-tailed RNA sequencing (RNA-seq) data of The Cancer Genome Atlas (TCGA) pancreatic cancer cohort and RDC was shown to outperform the other methods in prioritizing the most essential and biologically meaningful genes

Low-Cost Exoskeletons for Learning Whole-Arm Manipulation in the Wild

While humans can use parts of their arms other than the hands for manipulations like gathering and supporting, whether robots can effectively learn and perform the same type of operations remains relatively unexplored. As these manipulations require joint-level control to regulate the complete poses of the robots, we develop AirExo, a low-cost, adaptable, and portable dual-arm exoskeleton, for teleoperation and demonstration collection. As collecting teleoperated data is expensive and time-consuming, we further leverage AirExo to collect cheap in-the-wild demonstrations at scale. Under our in-the-wild learning framework, we show that with only 3 minutes of the teleoperated demonstrations, augmented by diverse and extensive in-the-wild data collected by AirExo, robots can learn a policy that is comparable to or even better than one learned from teleoperated demonstrations lasting over 20 minutes. Experiments demonstrate that our approach enables the model to learn a more general and robust policy across the various stages of the task, enhancing the success rates in task completion even with the presence of disturbances. Project website: https://airexo.github.io/Comment: Project page: https://airexo.github.io

A tandem array of ent-kaurene synthases in maize with roles in gibberellin and more specialized metabolism

While most commonly associated with its role in gibberellin (GA) phytohormone biosynthesis, ent-kaurene also serves as an intermediate in more specialized diterpenoid metabolism, as exemplified by the more than 800 known derived natural products. Among these are the maize kauralexins. However, no ent-kaurene synthases (KSs) have been identified from maize. The maize GA-deficient dwarf-5 (d5) mutant has been associated with a loss of KS activity. The relevant genetic lesion has been previously mapped, and was found here to correlate with the location of the KS-like gene ZmKSL3. Intriguingly, this forms part of a tandem array with two other terpene synthases (TPSs). Although one of these, ZmTPS1, has been previously reported to encode a sesquiterpene synthase, and both ZmTPS1 and that encoded by the third gene, ZmKSL5, have lost the N-terminal γ-domain prototypically associated with KS(L)s, all three genes fall within the KS(L) or TPS-e sub-family. Here it is reported that all three genes encode enzymes that are targeted to the plastid in planta, where diterpenoid biosynthesis is initiated, and which all readily catalyze the production of ent-kaurene. Consistent with the closer phylogenetic relationship of ZmKSL3 with previously identified KSs from cereals, only transcription of this gene is affected in d5 plants. On the other hand, the expression of all three of these genes is inducible, suggesting a role in more specialized metabolism, such as that of the kauralexins. Thus, these results clarify not only gibberellin phytohormone, but also diterpenoid phytoalexin biosynthesis in this important cereal crop plant

Characterization of CYP71Z18 indicates a role in maize zealexin biosynthesis

Maize (Zea mays) produces zealexins as phytoalexins, with the inducible production of these antibiotics providing biochemical protection against fungal infection. However, the biosynthesis of these sesquiterpenoids has remained unclear. In particular, it is unclear how the olefinic precursor, (S)-β-macrocarpene produced by the characterized maize sesquiterpene synthases TPS6/11, is further elaborated to form the bioactive zealexins. The first step is likely to be conversion of carbon-15 (C15) from a methyl group to a carboxylic acid by a cytochrome P450 mono-oxygenase (CYP). In this study, CYP71Z18, whose transcription is strongly induced by fungal infection, was found to catalyze oxidation of C15 in (S)-β-macrocarpene, forming zealexin A1. The inducible transcription of CYP71Z18 matches that observed for TPS6/11 and the accumulation of zealexins, which is consistent with a role for CYP71Z18 in sesquiterpenoid phytoalexin production. This completes identification of zealexin A1 biosynthesis, and represents the initial CYP identified for the production of maize terpenoid phytoalexins

Gp91phox (NOX2) in Activated Microglia Exacerbates Neuronal Damage Induced by Oxygen Glucose Deprivation and Hyperglycemia in an in Vitro Model

Background/Aims: Peri-operative cerebral ischemia reperfusion injury is one of the most serious peri-operative complications that can be aggravated in patients with diabetes. A previous study showed that microglia NOX2 (a NADPH oxidase enzyme) may play an important role in this process. Here, we investigated whether increased microglial derived gp91phox, also known as NOX2, reduced oxygen glucose deprivation (OGD) after induction of hyperglycemia (HG). Methods: A rat neuronal-microglial in vitro co-culture model was used to determine the effects of gp91phox knockdown on OGD after HG using six treatment groups: A rat microglia and neuron co-culture model was established and divided into the following six groups: high glucose + scrambled siRNA transfection (HG, n = 5); HG + gp91phoxsiRNA transfection (HG-gp91siRNA, n = 5); oxygen glucose deprivation + scrambled siRNA transfection (OGD, n = 5); OGD + gp91phoxsiRNA transfection (OGD-gp91siRNA, n = 5); HG + OGD + scrambled siRNA transfection (HG-OGD, n = 5); and HG + OGD + gp91phoxsiRNA transfection (HG-OGD-gp91siRNA, n = 5). The neuronal survival rate was measured by the MTT assay, while western blotting was used to determine gp91phox expression. Microglial derived ROS and neuronal apoptosis rates were analyzed by flow cytometry. Finally, the secretion of cytokines, including IL-6, IL-8, TNF-α, and 8-iso-PGF2α was determined using an ELISA kit. Results: Neuronal survival rates were significantly decreased by HG and OGD, while knockdown of gp91phox reversed these rates. ROS production and cytokine secretion were also significantly increased by HG and OGD but were significantly inhibited by knockdown of gp91phoxsiRNA. Conclusion: Knockdown of gp91phoxsiRNA significantly reduced oxidative stress and the inflammatory response, and alleviated neuronal damage after HG and OGD treatment in a rat neuronal-microglial co-culture model

Epidemiology of human anthrax in China, 1955-2014

Using national surveillance data for 120,111 human anthrax cases recorded during 1955-2014, we analyzed the temporal, seasonal, geographic, and demographic distribution of this disease in China. After 1978, incidence decreased until 2013, when it reached a low of 0.014 cases/100,000 population. The case-fatality rate, cumulatively 3.6% during the study period, has also decreased since 1990. Cases occurred throughout the year, peaking in August. Geographic distribution decreased overall from west to east, but the cumulative number of affected counties increased during 2005-2014. The disease has shifted from industrial to agricultural workers; 86.7% of cases occurred in farmers and herdsmen. Most (97.7%) reported cases were the cutaneous form. Although progress has been made in reducing incidence, this study highlights areas that need improvement. Adequate laboratory diagnosis is lacking; only 7.6% of cases received laboratory confirmation. Geographic expansion of the disease indicates that livestock control programs will be essential in eradicating anthrax

Study on the Dynamics of Differential Metabolites of Pu-erh Tea Fermented by Exogenous Added Bacteria

In order to explore the role of exogenous bacteria in the fermentation process of Pu-erh tea and its impact on tea quality, the present study aimed to explore the differences in metabolite changes during fermentation of Pu-erh tea treated with different bacterial strains. To achieve this, non-targeted metabolomics technology was employed, which was combined with multivariate statistical analysis and differential heat maps. The study analyzed the flavonoids, alkaloids, and terpenoids present in the tea samples. The H group was found to have a fruity and sweet aroma, a bright red soup color, and a strong and sweet taste. The A group had a strong floral and honey aroma, a bright red soup color, and a strong and sweet aftertaste. The R group had a fruity and milky aroma, a bright yellow soup color, and a strong but astringent and bitter taste. These differences in quality were found to be related to the levels of metabolites such as malvidin, genkwanin, catechins, caffeine, and lactucin. The study provided preliminary insights into the differences in metabolite content during the fermentation of Pu-erh tea with different bacterial strains, which can have varying effects on the taste, aroma, and soup color of the tea. The findings of this study could provide theoretical assistance for future Pu-erh tea fermentation

An oxyl/oxo mechanism for dioxygen bond formation in PSII revealed by X-ray free electron lasers

Photosynthetic water oxidation is catalyzed by the Mn4CaO5 cluster of photosystem II (PSII) with linear progression through five S-state intermediates (S0 to S4). To reveal the mechanism of water oxidation, we analyzed structures of PSII in the S1, S2, and S3 states by x-ray free-electron laser serial crystallography. No insertion of water was found in S2, but flipping of D1 Glu189 upon transition to S3 leads to the opening of a water channel and provides a space for incorporation of an additional oxygen ligand, resulting in an open cubane Mn4CaO6 cluster with an oxyl/oxo bridge. Structural changes of PSII between the different S states reveal cooperative action of substrate water access, proton release, and dioxygen formation in photosynthetic water oxidation

Capturing structural changes of the S-1 to S-2 transition of photosystem II using time-resolved serial femtosecond crystallography

Photosystem II (PSII) catalyzes light-induced water oxidation through an S-i-state cycle, leading to the generation of di-oxygen, protons and electrons. Pumpprobe time-resolved serial femtosecond crystallography (TR-SFX) has been used to capture structural dynamics of light-sensitive proteins. In this approach, it is crucial to avoid light contamination in the samples when analyzing a particular reaction intermediate. Here, a method for determining a condition that avoids light contamination of the PSII microcrystals while minimizing sample consumption in TR-SFX is described. By swapping the pump and probe pulses with a very short delay between them, the structural changes that occur during the S-1-to-S-2 transition were examined and a boundary of the excitation region was accurately determined. With the sample flow rate and concomitant illumination conditions determined, the S-2-state structure of PSII could be analyzed at room temperature, revealing the structural changes that occur during the S-1-to-S-2 transition at ambient temperature. Though the structure of the manganese cluster was similar to previous studies, the behaviors of the water molecules in the two channels (O1 and O4 channels) were found to be different. By comparing with the previous studies performed at low temperature or with a different delay time, the possible channels for water inlet and structural changes important for the water-splitting reaction were revealed