Observation of New Properties of Secondary Cosmic Rays Lithium, Beryllium, and Boron by the Alpha Magnetic Spectrometer on the International Space Station

We report on the observation of new properties of secondary cosmic rays Li, Be, and B measured in the rigidity (momentum per unit charge) range 1.9 GV to 3.3 TV with a total of 5.4×10^{6} nuclei collected by AMS during the first five years of operation aboard the International Space Station. The Li and B fluxes have an identical rigidity dependence above 7 GV and all three fluxes have an identical rigidity dependence above 30 GV with the Li/Be flux ratio of 2.0±0.1. The three fluxes deviate from a single power law above 200 GV in an identical way. This behavior of secondary cosmic rays has also been observed in the AMS measurement of primary cosmic rays He, C, and O but the rigidity dependences of primary cosmic rays and of secondary cosmic rays are distinctly different. In particular, above 200 GV, the secondary cosmic rays harden more than the primary cosmic rays.

Mechanical Effects of Cellulose, Xyloglucan, and Pectins on Stomatal Guard Cells of Arabidopsis thaliana

Stomata function as osmotically tunable pores that facilitate gas exchange at the surface of plants. Stomatal opening and closure are regulated by turgor changes in guard cells that result in mechanically regulated deformations of guard cell walls. However, how the molecular, architectural, and mechanical heterogeneities that exist in guard cell walls affect stomatal dynamics is unclear. In this work, stomata of wild type Arabidopsis thaliana plants or of mutants lacking normal cellulose, hemicellulose, or pectins were experimentally induced to close or open. Three-dimensional images of these stomatal complexes were collected using confocal microscopy, images were landmarked, and three-dimensional finite element models (FEMs) were constructed for each complex. Stomatal opening was simulated with a 5 MPa turgor increase. By comparing experimentally measured and computationally modeled changes in stomatal geometry across genotypes, anisotropic mechanical properties of guard cell walls were determined and mapped to cell wall components. Deficiencies in cellulose or hemicellulose were both predicted to stiffen guard cell walls, but differentially affected stomatal pore area and the degree of stomatal opening. Additionally, reducing pectin molecular mass altered the anisotropy of calculated shear moduli in guard cell walls and enhanced stomatal opening. Based on the unique architecture of guard cell walls and our modeled changes in their mechanical properties in cell wall mutants, we discuss how each polysaccharide class contributes to wall architecture and mechanics in guard cells. This study provides new insights into how the walls of guard cells are constructed to meet the mechanical requirements of stomatal dynamics.

Observation of the Identical Rigidity Dependence of He, C, and O Cosmic Rays at High Rigidities by the Alpha Magnetic Spectrometer on the International Space Station

We report the observation of new properties of primary cosmic rays He, C, and O measured in the rigidity (momentum/charge) range 2 GV to 3 TV with 90×10^{6} helium, 8.4×10^{6} carbon, and 7.0×10^{6} oxygen nuclei collected by the Alpha Magnetic Spectrometer (AMS) during the first five years of operation. Above 60 GV, these three spectra have identical rigidity dependence. They all deviate from a single power law above 200 GV and harden in an identical way.

[Genetic Polymorphisms of 17 Y-STR Loci in Nantong Han Population]

OBJECTIVES

To analyze the genetic phenotypes of Nantong Han population and evaluate the application value of 17 Y-STR loci in Nantong population.

METHODS

The peripheral blood samples were collected from 343 unrelated Nantong Han males and the genomic DNA were extracted by Chelex-100 method. Genotyping was performed using the AmpFℓSTR Yfiler™ Kit. The results were compared with other 12 Han populations, including Anhui, Jiangsu, Jiangxi, Shandong, Shanghai, Zhejiang （1）, Lanzhou, Nanyang, Luzhou, Mudanjiang, Shanxi and Zhejiang （2）, and 9 minority populations （Mongol, Xibe, Tibetan in Lhasa, Tibetan in Qinghai, Kazak, Uighur, Manchu, Paiwan in Taiwan and Tujia）.

RESULTS

A total of 327 different haplotypes were found in 17 Y-STR loci in Nantong Han population. The haplotype diversity （HD） was 0.999 7. The R_st value between Nantong Han and other Chinese populations ranged from -0.000 6 to 0.263 5. The multidimensional scaling results showed that Nantong Han population had no significant differences between most of the Han populations, but had significant differences between most of Chinese minority populations.

CONCLUSIONS

Seventeen Y-STR loci can be a powerful tool for forensic application because of its high polymorphism in Nantong Han population.

POLYGALACTURONASE INVOLVED IN EXPANSION3 Functions in Seedling Development, Rosette Growth, and Stomatal Dynamics in Arabidopsis thaliana

Plant cell separation and expansion require pectin degradation by endogenous pectinases such as polygalacturonases, few of which have been functionally characterized. Stomata are a unique system to study both processes because stomatal maturation involves limited separation between sister guard cells and stomatal responses require reversible guard cell elongation and contraction. However, the molecular mechanisms for how stomatal pores form and how guard cell walls facilitate dynamic stomatal responses remain poorly understood. We characterized POLYGALACTURONASE INVOLVED IN EXPANSION3 (PGX3), which is expressed in expanding tissues and guard cells. PGX3-GFP localizes to the cell wall and is enriched at sites of stomatal pore initiation in cotyledons. In seedlings, ablating or overexpressing PGX3 affects both cotyledon shape and the spacing and pore dimensions of developing stomata. In adult plants, PGX3 affects rosette size. Although stomata in true leaves display normal density and morphology when PGX3 expression is altered, loss of PGX3 prevents smooth stomatal closure, and overexpression of PGX3 accelerates stomatal opening. These phenotypes correspond with changes in pectin molecular mass and abundance that can affect wall mechanics. Together, these results demonstrate that PGX3-mediated pectin degradation affects stomatal development in cotyledons, promotes rosette expansion, and modulates guard cell mechanics in adult plants.

Ultrafast spin-polarized electron dynamics in the unoccupied topological surface state of Bi2Se3

The three-dimensional topological insulator Bi₂Se₃ presents two cone-like dispersive topological surface states centered at the [Formula: see text] point. One of them is unoccupied in equilibrium conditions and located 1.8 eV above the other one lying close to the Fermi level. In this work we employ time- and angle-resolved photoemission spectroscopy with circularly polarized pump photons to selectively track the spin dynamics of the empty topological states. We observe that spin-polarized electrons flow along the topological cone and recombine towards the unpolarized bulk states on a timescale of few tens of femtoseconds. This provides direct evidence of the capability to trigger a spin current with circularly polarized light.

Activation tagging of Arabidopsis POLYGALACTURONASE INVOLVED IN EXPANSION2 promotes hypocotyl elongation, leaf expansion, stem lignification, mechanical stiffening, and lodging

Pectin is the most abundant component of primary cell walls in eudicot plants. The modification and degradation of pectin affects multiple processes during plant development, including cell expansion, organ initiation, and cell separation. However, the extent to which pectin degradation by polygalacturonases affects stem development and secondary wall formation remains unclear. Using an activation tag screen, we identified a transgenic Arabidopsis thaliana line with longer etiolated hypocotyls, which overexpresses a gene encoding a polygalacturonase. We designated this gene as POLYGALACTURONASE INVOLVED IN EXPANSION2 (PGX2), and the corresponding activation tagged line as PGX2^AT . PGX2 is widely expressed in young seedlings and in roots, stems, leaves, flowers, and siliques of adult plants. PGX2-GFP localizes to the cell wall, and PGX2^AT plants show higher total polygalacturonase activity and smaller pectin molecular masses than wild-type controls, supporting a function for this protein in apoplastic pectin degradation. A heterologously expressed, truncated version of PGX2 also displays polygalacturonase activity in vitro. Like previously identified PGX1^AT plants, PGX2^AT plants have longer hypocotyls and larger rosette leaves, but they also uniquely display early flowering, earlier stem lignification, and lodging stems with enhanced mechanical stiffness that is possibly due to decreased stem thickness. Together, these results indicate that PGX2 both functions in cell expansion and influences secondary wall formation, providing a possible link between these two developmental processes.

Abstract P5-10-01: Adherence to healthy lifestyle behaviors in a predominantly Hispanic population of women undergoing screening mammography

This abstract was not presented at the symposium.

The miR-487b-3p/GRM3/TGFβ signaling axis is an important regulator of colon cancer tumorigenesis

Molecular targeting is an import strategy to treat advanced colon cancer. The current study demonstrates that expression of GRM3, a metabotropic glutamate receptor mainly expressed in mammalian central nervous system, is significantly upregulated in majority of human colonic adenocarcinomas tested and colon cancer cell lines. Knockdown of GRM3 expression or inhibition of GRM3 activation in colon cancer cells reduces cell survival and anchorage-independent growth in vitro and inhibits tumor growth in vivo. Mechanistically, GRM3 antagonizes TGFβ-mediated activation of protein kinase A and inhibition of AKT. In addition, TGFβ signaling increases GRM3 protein stability and knockdown of GRM3 enhances TGFβ-mediated tumor suppressor function. Further studies indicate that miR-487b-3p directly targets GRM3. Overexpression of miR-487b-3p mimics the effects of GRM3 knockdown and suppresses the tumorigenicity of colon cancer cells in vivo. Expression of miR-487b-3p is decreased in colon adenocarcinomas and inversely correlates with GRM3 expression. Taken together, these studies indicate that upregulation of GRM3 expression is a functionally important molecular event in colon cancer, and that GRM3 is a promising molecular target for colon cancer treatment. This is particularly interesting and important from a therapeutic standpoint because numerous metabotropic glutamate receptor antagonists are available, many of which have been found unsuitable for treatment of neuropsychiatric disorders for reasons such as inability to readily penetrate blood brain barriers. Since GRM3 is upregulated in colon cancer, but rarely expressed in normal peripheral tissues, targeting GRM3 with such agents would not likely cause adverse neurological or peripheral side effects, making GRM3 an attractive and specific molecular target for colon cancer treatment.

Enhanced magnetization in unusual carbon-nanotube/carbon-foam cm-scale hybrid-buckypaper films with high α-Fe filling-ratio

We report the synthesis of novel and unusual α-Fe-filled carbon nanotube (CNT)/carbon foam (CFM) hybrid-buckypaper films via pyrolysis of ferrocene/dichlorobenzene mixtures.

Precision Measurement of the Boron to Carbon Flux Ratio in Cosmic Rays from 1.9 GV to 2.6 TV with the Alpha Magnetic Spectrometer on the International Space Station

Knowledge of the rigidity dependence of the boron to carbon flux ratio (B/C) is important in understanding the propagation of cosmic rays. The precise measurement of the B/C ratio from 1.9 GV to 2.6 TV, based on 2.3 million boron and 8.3 million carbon nuclei collected by AMS during the first 5 years of operation, is presented. The detailed variation with rigidity of the B/C spectral index is reported for the first time. The B/C ratio does not show any significant structures in contrast to many cosmic ray models that require such structures at high rigidities. Remarkably, above 65 GV, the B/C ratio is well described by a single power law R^{Δ} with index Δ=-0.333±0.014(fit)±0.005(syst), in good agreement with the Kolmogorov theory of turbulence which predicts Δ=-1/3 asymptotically.

Antiproton Flux, Antiproton-to-Proton Flux Ratio, and Properties of Elementary Particle Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station

A precision measurement by AMS of the antiproton flux and the antiproton-to-proton flux ratio in primary cosmic rays in the absolute rigidity range from 1 to 450 GV is presented based on 3.49×10^{5} antiproton events and 2.42×10^{9} proton events. The fluxes and flux ratios of charged elementary particles in cosmic rays are also presented. In the absolute rigidity range ∼60 to ∼500  GV, the antiproton p[over ¯], proton p, and positron e^{+} fluxes are found to have nearly identical rigidity dependence and the electron e^{-} flux exhibits a different rigidity dependence. Below 60 GV, the (p[over ¯]/p), (p[over ¯]/e^{+}), and (p/e^{+}) flux ratios each reaches a maximum. From ∼60 to ∼500  GV, the (p[over ¯]/p), (p[over ¯]/e^{+}), and (p/e^{+}) flux ratios show no rigidity dependence. These are new observations of the properties of elementary particles in the cosmos.

Integrating cell biology, image analysis, and computational mechanical modeling to analyze the contributions of cellulose and xyloglucan to stomatal function

Cell walls are likely to be essential determinants of the amazing strength and flexibility of the guard cells that surround each stomatal pore in plants, but surprisingly little is known about cell wall composition, organization, and dynamics in guard cells. Recent analyses of cell wall organization and stomatal function in the guard cells of Arabidopsis thaliana mutants with defects in cellulose and xyloglucan have allowed for the development of new hypotheses about the relative contributions of these components to guard cell function. Advanced image analysis methods can allow for the automated detection of key structures, such as microtubules (MTs) and Cellulose Synthesis Complexes (CSCs), in guard cells, to help determine their contributions to stomatal function. A major challenge in the mechanical modeling of dynamic biological structures, such as guard cell walls, is to connect nanoscale features (e.g., wall polymers and their molecular interactions) with cell-scale mechanics; this challenge can be addressed by applying multiscale computational modeling that spans multiple spatial scales and physical attributes for cell walls.

Association between lutein intake and lutein concentrations in human milk samples from lactating mothers in South Korea

This study was performed to investigate the association between maternal lutein intake and lutein concentrations in human milk among exclusive breast-feeding and mixed-feeding groups of lactating mothers in South Korea. From 99 women who were recruited from March to July 2015, dietary data and breast milk samples were obtained. The means of the daily lutein intakes and breast milk lutein concentrations in lactating mothers were 4.04 mg/day and 10.06 μg/dl, respectively, and they did not differ according to the type of breast-feeding. Breast milk lutein concentrations were positively correlated with the dietary lutein intake of lactating mothers after adjustment for the infant's age and supplement use by the lactating women (r=0.3337, P=0.0008). These correlations appeared in both groups. Further research is needed to identify whether breast milk lutein levels influence infant health, especially eye health.European Journal of Clinical Nutrition advance online publication, 25 May 2016; doi:10.1038/ejcn.2016.84.

A pilot study on association between phthalate exposure and missed miscarriage

OBJECTIVE

The incidence of missed miscarriage has been increasing during the past decade in China and the etiology of about half of the cases remains unclear. Exposure to phthalates has been considered as a risk factor. The aim of this paper is to assess the association between exposure to phthalates and missed miscarriage.

PATIENTS AND METHODS

A case-control study was performed including 150 cases of missed miscarriage and 150 matched controls with normal pregnancies. The levels of phthalate exposure were compared between the two groups by measuring 13 phthalate metabolites in urine samples. Blood samples were collected for serum hormone measurement to assess the relationship between serum hormone level and phthalate exposure.

RESULTS

The urinary levels of metabolites of di-(2-ethylhexyl) phthalate (DEHP) and dimethyl phthalate (DMP) were significantly higher in the cases than in the controls. A strong dose-response relationship was observed between urinary metabolite levels and the odds of missed miscarriage. Monomethyl phthalate (MMP), a metabolite of DMP, and mono-2-ethylhexyl phthalate (MEHP), a metabolite of DEHP, each had significant negative correlation with maternal serum hormone levels.

CONCLUSIONS

In the current study, exposure to DEHP and DMP was found to be associated with missed miscarriage. Interruption of hormone synthesis by DMP and DEHP metabolites represents a plausible mechanism of phthalate reproductive toxicity.

HSV vector-mediated GAD67 suppresses neuropathic pain induced by perineural HIV gp120 in rats through inhibition of ROS and Wnt5a

Human immunodeficiency virus (HIV)-related neuropathic pain is a debilitating chronic condition that is severe and unrelenting. Despite the extensive research, the exact neuropathological mechanisms remain unknown, which hinders our ability to develop effective treatments. Loss of GABAergic tone may play an important role in the neuropathic pain state. Glutamic acid decarboxylase 67 (GAD67) is one of isoforms that catalyze GABA synthesis. Here, we used recombinant herpes simplex virus (HSV-1) vectors that encode gad1 gene to evaluate the therapeutic potential of GAD67 in peripheral HIV gp120-induced neuropathic pain in rats. We found that 1) subcutaneous inoculation of the HSV vectors expressing GAD67 attenuated mechanical allodynia in the model of HIV gp120-induced neuropathic pain, 2) the anti-allodynic effect of GAD67 was reduced by GABA-A and-B receptors antagonists, 3) HSV vectors expressing GAD67 reversed the lowered GABA-IR expression, and 4) the HSV vectors expressing GAD67 suppressed the upregulated mitochondrial superoxide and Wnt5a in the spinal dorsal horn. Taken together, our studies support the concept that recovering GABAergic tone by the HSV vectors may reverse HIV-associated neuropathic pain through suppressing mitochondrial superoxide and Wnt5a. Our studies provide validation of HSV-mediated GAD67 gene therapy in the treatment of HIV-related neuropathic pain.