Periodicities in the Daily Proton Fluxes from 2011 to 2019 Measured by the Alpha Magnetic Spectrometer on the International Space Station from 1 to 100 GV

We present the precision measurement of the daily proton fluxes in cosmic rays from May 20, 2011 to October 29, 2019 (a total of 2824 days or 114 Bartels rotations) in the rigidity interval from 1 to 100 GV based on 5.5×10^{9} protons collected with the Alpha Magnetic Spectrometer aboard the International Space Station. The proton fluxes exhibit variations on multiple timescales. From 2014 to 2018, we observed recurrent flux variations with a period of 27 days. Shorter periods of 9 days and 13.5 days are observed in 2016. The strength of all three periodicities changes with time and rigidity. The rigidity dependence of the 27-day periodicity is different from the rigidity dependences of 9-day and 13.5-day periods. Unexpectedly, the strength of 9-day and 13.5-day periodicities increases with increasing rigidities up to ∼10  GV and ∼20  GV, respectively. Then the strength of the periodicities decreases with increasing rigidity up to 100 GV.

Research progress on the regulation mechanism of probiotics on the microecological flora of infected intestines in livestock and poultry

The animal intestine is a complex ecosystem composed of host cells, gut microbiota and available nutrients. Gut microbiota can prevent the occurrence of intestinal diseases in animals by regulating the homeostasis of the intestinal environment. The intestinal microbiota is a complex and stable microbial community, and the homeostasis of the intestinal environment is closely related to the invasion of intestinal pathogens, which plays an important role in protecting the host from pathogen infections. Probiotics are strains of microorganisms that are beneficial to health, and their potential has recently led to a significant increase in studies on the regulation of intestinal flora. Various potential mechanisms of action have been proposed on probiotics, especially mediating the regulation mechanism of the intestinal flora on the host, mainly including competitive inhibition of pathogens, stimulation of the host's adaptive immune system and regulation of the intestinal flora. The advent of high-throughput sequencing technology has given us a clearer understanding and has facilitated the development of research methods to investigate the intestinal microecological flora. This review will focus on the regulation of probiotics on the microbial flora of intestinal infections in livestock and poultry and will depict future research directions.

ToxR modulates biofilm formation in fish pathogen Vibrio harveyi

Vibrio harveyi is a common aquaculture pathogen causing diseases in a variety of aquatic animals. toxR, a conserved virulence-associated gene in vibrios, is identified in V. harveyi 345, a pathogenic strain isolated from diseased fish. In this study, to gain insight into function of ToxR in V. harveyi, an in-frame deletion of the toxR gene was constructed to reveal the role of ToxR in the physiology and virulence of V. harveyi. The statistical analysis showed no significant differences in the growth ability, motility, extracellular protease secretion, antibiotic susceptibility, virulence by intraperitoneal injection and the ability of V. harveyi to colonize the spleen and liver tissues of the pearl gentian grouper between the wild-type (WT) and the toxR mutant. However, the deletion of toxR increased the biofilm formation. The structure of the V. harveyi biofilm was further analysed by using scanning electron microscopy (SEM) and confocal laser scanning microscopy, and the results showed that deletion of toxR increased the number and density of V. harveyi biofilm. Since biofilm production is flagella, exopolysaccharide (EPS) and lipopolysaccharide dependent, 16 of V. harveyi biofilm-related genes were selected for further analysis. Based on quantitative real-time reverse transcription-PCR, the expression levels of these genes, including genes flrB, motY and mshA, flaE, flrA and gmhD, were significantly up-regulated in the ΔtoxR⁺ strain as compared with the WT⁺ and C-ΔtoxR strains during the early and mid-exponential, while epsG, flaA, flaE, flgD, flgE, flrB, flrC, lpxB, motY, mshA and scrG genes were inhibited because of deletion of the toxR gene in the stationary growth phase. Our results indicate that ToxR plays an important role in controlling the biofilm in V. harveyi.

Study on a new manner of the magnetization switching actuated by a unidirectional pulse current

A new writing scheme with a unidirectional pulse current is proposed for spin transfer torque (STT) based magnetic random-access memory (MRAM). To investigate the feasibility of the writing scheme, bilayered nano-pillars composed of a soft layer with small in-plane shape anisotropy and a hard layer with either large perpendicular anisotropy (PMA) or in-plane anisotropy (IMA) are designed and their switching behaviors are studied. It is found that in either type of bilayered nano-pillars, with the aid of the attached hard layer, the magnetization of the soft layer can be switched back and forth under a unidirectional pulse current. In an IMA/IMA nano-pillar, the magnetization of the free layer (FL) can achieve excellent alignment, which is in contrast to the IMA/PMA nano-pillar. By optimizing the dimensions and magnetic parameters of the IMA/IMA nano-pillar, a decently low switching current density (4.3 × 10¹¹A m^-2) and ultrashort switching time (<1 ns) can be reached. Based on these results, the unidirectional writing scheme is practical if an IMA/IMA bilayer is used to replace the FL in a magnetic tunnel junction. Considering that a unidirectional writing scheme can enable the application of materials with high spin polarization such as half metals, and avoid the injection of writing current into junction using a special design, it may be very promising for STT-MRAM.

Erratum: Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen [Phys. Rev. Lett. 127, 021101 (2021)]

This corrects the article DOI: 10.1103/PhysRevLett.127.021101.

Development and validation of a three-immune-related gene signature prognostic risk model in papillary thyroid carcinoma

PURPOSE

Increasing evidence indicates that there is a correlation between papillary thyroid carcinoma (PTC) prognosis and the immune signature. Our goal was to construct a new prognostic tool based on immune genes to achieve more accurate prognosis predictions and earlier diagnoses of PTC.

METHODS

The 493 PTCs samples and 58 tumor-adjacent normal tissues were obtained from The Cancer Genome Atlas database (TCGA). Immune genes were obtained from the ImmPort database. First, this cohort was randomly divided into training cohort and testing cohort. Second, the differentially expressed (DE) immune genes from the training set were used to construct the prognostic model. Then, the testing and entire data cohorts were used to validate the model, and the data were analyzed to determine the correlation of the clinical prognostic model with immune cell infiltration and expression profiles of human leukocyte antigen (HLA) genes. Finally, an analysis of the gene ontology (GO) annotation was performed.

RESULTS

A total of 189 upregulated and 128 downregulated DE immune genes were identified. We developed and validated a three-immune gene model for PTC that includes Hsp70, NOX5, and FGF23. This model was demonstrated to be an independent prognostic variable. In addition, the overall immune activity of the high-risk group was higher than that of the low-risk group.

CONCLUSIONS

We developed and validated a three-immune gene model for PTC that includes HSPA1A, NOX5, and FGF23. This model can be used as a validated tool to predict outcomes in PTC.

TaASR1-D confers abiotic stress resistance by affecting ROS accumulation and ABA signalling in transgenic wheat

Cultivating new crop cultivars with multiple abiotic stress tolerances is important for crop production. The abscisic acid-stress-ripening (ASR) protein has been shown to confer abiotic stress tolerance in plants. However, the mechanisms of ASR function under stress condition remain largely unclear. In this study, we characterized all ASR family members in common wheat and constitutively overexpressed TaASR1-D in a commercial hexaploid wheat cultivar Zhengmai 9023. The transgenic wheat plants exhibited increased tolerance to multiple abiotic stresses and increased grain yields under salt stress condition. Overexpression of TaASR1-D conferred enhanced antioxidant capacity and ABA sensitivity in transgenic wheat plants. Further, RNA in situ hybridization results showed that TaASR1-D had higher expression levels in the vascular tissues of leaves and the parenchyma cells around the vascular tissues of roots and stems. Yeast one-hybrid and electrophoretic mobility shift assays revealed that TaASR1-D could directly bind the specific cis-elements in the promoters of TaNCED1 and TaGPx1-D. In conclusion, our findings suggest that TaASR1-D can be used to breed new wheat cultivars with increased multiple abiotic stress tolerances, and TaASR1-D enhances abiotic stress tolerances by reinforcing antioxidant capacity and ABA signalling.

Dental Pulp Stem Cell Polarization: Effects of Biophysical Factors

Dental pulp stem cells (DPSCs) have the potential to polarize, differentiate, and form tubular dentin under certain conditions. However, the factors that initiate and regulate DPSC polarization and its underlying mechanism remain unclear. Identification of the factors that control DPSC polarization is a prerequisite for tubular dentin regeneration. We recently developed a unique bioinspired 3-dimensional platform that is capable of deciphering the factors that initiate and modulate cell polarization. The bioinspired platform has a simple background and confines a single cell on each microisland of the platform; therefore, it is an effective tool to study DPSC polarization at the single-cell level. In this work, we explored the effects of biophysical factors (surface topography, microisland area, geometry, tubular size, and gravity) on single DPSC polarization. Our results demonstrated that nanofibrous architecture, microisland area, tubular size, and gravity participated in regulating DPSC polarization by influencing the formation of the DPSC process and relocation of the Golgi apparatus. Among these factors, nanofibrous architecture, tubular size, and appropriate microisland area were indispensable for initiating DPSC polarization, whereas gravity served as an auxiliary factor to the process of DPSC polarization. Meanwhile, microisland geometry had a limited effect on DPSC polarization. Collectively, this work provides information on DPSC polarization and paves the way for the development of new biomaterials for tubular dentin regeneration.

Properties of a New Group of Cosmic Nuclei: Results from the Alpha Magnetic Spectrometer on Sodium, Aluminum, and Nitrogen

We report the properties of sodium (Na) and aluminum (Al) cosmic rays in the rigidity range 2.15 GV to 3.0 TV based on 0.46 million sodium and 0.51 million aluminum nuclei collected by the Alpha Magnetic Spectrometer experiment on the International Space Station. We found that Na and Al, together with nitrogen (N), belong to a distinct cosmic ray group. In this group, we observe that, similar to the N flux, both the Na flux and Al flux are well described by the sums of a primary cosmic ray component (proportional to the silicon flux) and a secondary cosmic ray component (proportional to the fluorine flux). The fraction of the primary component increases with rigidity for the N, Na, and Al fluxes and becomes dominant at the highest rigidities. The Na/Si and Al/Si abundance ratios at the source, 0.036±0.003 for Na/Si and 0.103±0.004 for Al/Si, are determined independent of cosmic ray propagation.

Cigarette Smoke Exposure Inhibits Osteoclast Apoptosis via the mtROS Pathway

It is widely known that smoking is a risk factor for bone loss and plays a key role in osteopenia. Despite this well-known association, the mechanisms by which smoking affects bone have not been definitively established. Since smoking increases bone loss and potentially affects bone resorption in response to mechanical force, we investigated the impact of cigarette smoke on osteoclast numbers and underlying mechanisms in a mouse model of orthodontic tooth movement (OTM). The experimental group was exposed to once-daily cigarette smoke while the control group was not, and tooth movement distance and osteoclast numbers were assessed. In addition, the effect of cigarette smoke extract (CSE) on osteoclast precursor proliferation and osteoclast apoptosis was assessed in vitro. We found that cigarette smoke exposure enhanced bone remodeling stimulated by mechanical force and increased osteoclast numbers in vivo. Also, CSE increased the number of osteoclasts by inhibiting osteoclast apoptosis via the mitochondrial reactive oxygen species/cytochrome C/caspase 3 pathway in vitro. Moreover, exposure of mice to cigarette smoke affected bone marrow cells, leading to increased formation of osteoclasts in vitro. This study identifies a previously unknown mechanism of how smoking has a detrimental impact on bone.

[Mechanism of hepatocyte mitochondrial NDUFA13 deficiency-induced liver fibrogenesis: the role of abnormal hepatic stellate cell activation]

OBJECTIVE

To investigate the role of hepatocyte mitochondrial NDUFA13 loss in the liver fibrogenesis in mice and explore the possible mechanisms.

OBJECTIVE

We used liver-specific NDUFA13 heterozygous knockout mouse models (NDUFA13^fl/-; Alb-Cre) established previously by intercrossing NDUFA13^fl/fl and Alb-Cre mice, with their littermate control NDUFA13^fl/fl mice as the control (n=8). The mice were euthanized at the age of 4 weeks and 2 years, and the liver tissues were collected for HE and Masson staining to observe the pathological changes and fibrosis phenotypes. Western blotting was performed to detect the expression of NDUFA13 protein in the liver tissues, and the infiltration of F4/80⁺ macrophages and the expressions of TGF-β1, TNF-α and IL-1β were analyzed by immunofluorescence assay. The expression levels of α-SMA, matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteases 1 (TIMP-1), collagen-Ⅰ and collagen-Ⅲ were assayed by immunohistochemistry.

OBJECTIVE

HE and Masson staining showed obvious inflammatory infiltration but no significant fibrosis in the liver tissues of 4-week-old NDUFA13^fl/- mice, but severe liver damage with massive fibrosis was observed in 2-year-old NDUFA13^fl/- mice. NDUFA13 expression in 2-year-old NDUFA13^fl/- mice markedly decreased compared with that in the control NDUFA13^fl/fl mice as shown by Western blotting (P < 0.05). Immunohistochemistry showed obvious infiltration of F4/80⁺ macrophages in the liver tissue with a large amount of TGF-β1 production (P < 0.05) and TNF-α and IL-1β secretions in NDUFA13^fl/- mice (P < 0.05). NDUFA13 knockout obviously promoted α-SMA expression (P < 0.05) and collagen-Ⅰ and collagen-Ⅲ deposition (P < 0.05) while significantly decreased MMP-9 and increased TIMP-1 expression in the liver (P < 0.05).

OBJECTIVE

Hepatocytes-specific NDUFA13 deficiency can trigger spontaneous and chronic liver fibrosis phenotypes in mice probably in association with abnormal activation of hepatic stellate cells induced by macrophages and inflammatory factors.

[Exenatide promotes cholesterol efflux in pancreatic tissue of obese diabetic rats]

OBJECTIVE

To study the effect of exenatide on the expression of ABCA1 and cholesterol metabolism in the pancreas of obese diabetic rats.

OBJECTIVE

Twenty-four normal male SD rats and 18 obese diabetic rats (induced by high-fat feeding and STZ injection) were both divided equally into 2 groups for injections of saline or exenatide. After treatment for a week, the expression of ABCA1, cholesterol metabolism, and islet function of the rats were examined using real-time PCR, Western blotting, oil red O staining, cholesterol content determination, and HE staining.

OBJECTIVE

The expressions of ABCA1 at both mRNA and protein levels in pancreatic tissue were significantly lower in obese diabetic rats than in normal SD rats. The obese diabetic rats showed obvious lipid deposition and increased cholesterol content in the pancreatic tissue with significantly reduced islet volume and structural changes (P < 0.05); exenatide treatment of the diabetic rats significantly up-regulated ABCA1 expression, reduced lipid deposition and cholesterol content in pancreatic tissue, and increased number and volume of the islets, which presented with more orderly alignment (P < 0.05).

OBJECTIVE

Obese diabetic rats have lowered ABCA1 expression, cholesterol efflux block, and cholesterol accumulation in the pancreatic tissue. Exenatide can up-regulate ABCA1 expression and promote cholesterol efflux to reduce cholesterol content in the pancreatic tissue and improve islet function in obese diabetic rats.