Description: A statistical study was made on both the energy dependence of the low-frequency quasi-periodic oscillation (QPO) amplitude (LFQPO amplitude spectrum) and the LFQPO amplitude from all the RXTE observations of GRS 1915+105. Based on the two-branch correlation of the LFQPO frequency and the hardness ratio, the observations that were suitable for evaluating the LFQPO amplitude spectrum were divided into two groups. According to a comparison between the radio and X-ray emissions, we deduced that the jets during the two groups of observations are very different. A negative correlation between the LFQPO frequency and the radio flux was found for one group. The LFQPO amplitude spectrum was fitted by a power law with an exponential cutoff in order to describe it quantitatively. It reveals that as the LFQPO frequency increases, the power law hardens. Furthermore, the cutoff energy first decreases, and then smoothly levels off. The fit also shows that the LFQPO amplitude spectra of the two groups are essentially the same, suggesting that the LFQPO does not originate from the jet. The LFQPO amplitude spectra are hard, indicating a possible origin of the LFQPO in the corona. As the LFQPO frequency increases, the LFQPO amplitude first increases and then decreases. The effects of the low-pass filter and the jet on the LFQPO amplitude are discussed.

Description: Because of its widespread occurrence and role in shaping evolutionary processes in the biological kingdom, especially in plants, polyploidy has been increasingly studied from cytological to molecular levels. By inferring gene order, gene distances and gene homology, linkage mapping with molecular markers has proven powerful for investigating genome structure and organization. Here we review and assess a general statistical model for three-point linkage analysis in autotetraploids by integrating double reduction, a phenomenon that commonly occurs in autopolyploids whose chromosomes are derived from a single ancestral species. This model does not require any assumption on the distribution of the occurrence of double reduction and can handle the complexity of multilocus linkage in terms of crossover interference. Implemented with the expectation-maximization (EM) algorithms, the model can estimate and test the recombination fractions between less informative dominant markers, thus facilitating its practical implications for any autopolyploids in most of which inexpensive dominant markers are still used for their genetic and evolutionary studies. The model was applied to reanalyze a published data in tetraploid switchgrass, validating its practical usefulness and utilization.

Description: An astrometry project on PSR B1257+12, a millisecond pulsar with a planetary system, has been carried out with the Very Long Baseline Array and the European Very Long Baseline Interferometry (VLBI) Network at the central frequencies of 1465 and 1540 MHz, respectively. This project consists of nine epochs of phase-referenced observations spanning about two years. Model-independent estimates of the distance and velocity of this pulsar have been obtained using VLBI astrometry for the first time. The precise distance to PSR B1257+12 is 710 –38 +43 pc. This is in agreement with the timing results, but is larger than the predictions from dispersion measurements using Galactic electron density distribution models. The measured proper-motion components of PSR B1257+12 in right ascension and declination are 46.44 ± 0.08 and –84.87 ± 0.32 mas yr –1 , respectively. The corresponding transverse velocity of PSR B1257+12 is ~326 km s –1 , making it the only millisecond pulsar known so far with a velocity clearly exceeding 300 km s –1 . Based on these results, the apparent X-ray efficiency of this pulsar is estimated to be in the same range as other millisecond pulsars, which is not as low as previously thought. The planets around PSR B1257+12 should be formed in a protoplanetary disc. We review possible evolutionary scenarios for the protoplanetary disc, and conclude that the protoplanetary disc of this pulsar has most probably been formed by the evaporation or disruption of its companion in a binary.

Description: Qidong City, China, has had high liver cancer incidence from endemic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin. Based on etiologic studies, we began interventions in 1980 to reduce dietary aflatoxin and initiate neonatal HBV vaccination. We studied trends in liver cancer incidence rates in the 1.1 million inhabitants of Qidong and examined trends in aflatoxin exposure, staple food consumption, HBV infection markers and annual income. Aflatoxin exposure declined greatly in association with economic reform, increased earnings and educational programs to shift staple food consumption in the total population from moldy corn to fresh rice. A controlled neonatal HBV vaccination trial began in 1983 and ended in November, 1990, when vaccination was expanded to all newborns. Liver cancer incidence fell dramatically in young adults. Compared with 1980–83, the age-specific liver cancer incidence rates in 2005–08 significantly decreased 14-fold at ages 20–24, 9-fold at ages 25–29, 4-fold at ages 30–34, 1.5-fold at ages 35–39, 1.2-fold at ages 40–44 and 1.4-fold at ages 45–49, but increased at older ages. The 14-fold reduction at ages 20–24 might reflect the combined effects of reduced aflatoxin exposure and partial neonatal HBV vaccination. Decrease incidence in age groups 〉25 years could mainly be attributable to rapid aflatoxin reduction. Compared with 1980–83, liver cancer incidence in 1990–93 significantly decreased 3.4-fold at ages 20–24, and 1.9-fold at ages 25–29 when the first vaccinees were 〈11 years old.

Description: Group B streptococcus (GBS) can cause severe disease in susceptible hosts, including newborns, pregnant women, and the elderly. GBS serine-rich repeat (Srr) surface glycoproteins are important adhesins/invasins in multiple host tissues, including the vagina. However, exact molecular mechanisms contributing to their importance in colonization are unknown. We have recently determined that Srr proteins contain a fibrinogen-binding region (BR) and hypothesize that Srr-mediated fibrinogen binding may contribute to GBS cervicovaginal colonization. In this study, we observed that fibrinogen enhanced wild-type GBS attachment to cervical and vaginal epithelium, and that this was dependent on Srr1. Moreover, purified Srr1-BR peptide bound directly to host cells, and peptide administration in vivo reduced GBS recovery from the vaginal tract. Furthermore, a GBS mutant strain lacking only the Srr1 "latching" domain exhibited decreased adherence in vitro and decreased persistence in a mouse model of GBS vaginal colonization, suggesting the importance of Srr–fibrinogen interactions in the female reproductive tract.

Description: 346 new CCD observations during the years 2011–2014 have been reduced to derive the precise positions of Phoebe, the ninth satellite of Saturn. The observations were made by the 2.4 m telescope at Yunnan Observatory over nine nights. Due to the use of a focal-reducer on the telescope, its significant geometric distortion is solved for and removed for each CCD field of view. The positions of Phoebe are measured with respect to the stars in UCAC2 catalogue. The theoretical position of Phoebe was retrieved from the Institute de Méchanique Céleste et de Calcul des Éphémérides ephemeris which includes the latest theory PH12 by Desmars et al., while the position of Saturn was obtained from the Jet Propulsion Laboratory ephemeris DE431. Our results show that the mean O–Cs (observed minus computed) are –0.02 and –0.07 arcsec in right ascension and declination, respectively. The dispersions of our observations are estimated at about 0.04 arcsec in each direction.

Description: The homophilic cell surface receptors CD150 (Slamf1) and CD352 (Slamf6) are known to modulate adaptive immune responses. Although the T h 17 response was enhanced in Slamf6 –/– C57BL/6 mice upon oral infection with Citrobacter rodentium , the pathologic consequences are indistinguishable from an infection of wild-type C57BL/6 mice. Using a reporter-based binding assay, we show that Slamf6 can engage structures on the outer cell membrane of several Gram – bacteria. Therefore, we examined whether Slamf6, like Slamf1, is also involved in innate responses to bacteria and regulates peripheral inflammation by assessing the outcome of C. rodentium infections in Rag –/– mice. Surprisingly, the pathology and immune responses in the lamina propria of C. rodentium -infected Slamf6 –/– Rag –/– mice were markedly reduced as compared with those of Rag –/– mice. Infiltration of inflammatory phagocytes into the lamina propria was consistently lower in Slamf6 –/– Rag –/– mice than in Rag –/– animals. Concomitant with the reduced systemic translocation of the bacteria was an enhanced production of IL-22, suggesting that Slamf6 suppresses a mucosal protective program. Furthermore, administering a mAb (330) that inhibits bacterial interactions with Slamf6 to Rag –/– mice ameliorated the infection compared with a control antibody. We conclude that Slamf6-mediated interactions of colonic innate immune cells with specific Gram – bacteria reduce mucosal protection and enhance inflammation, contributing to lethal colitis that is caused by C. rodentium infections in Rag –/– mice.

Description: Calnexin (CNX), known as a lectin chaperone located in the endoplasmic reticulum (ER), specifically recognizes G 1 M 9 GN 2 -proteins and facilitates their proper folding with the assistance of ERp57 in mammalian cells. However, it has been left unidentified how CNX works in Aspergillus oryzae , which is a filamentous fungus widely exploited in biotechnology. In this study, we found that a protein disulfide isomerase homolog TigA can bind with A. oryzae CNX (AoCNX), which was revealed to specifically recognize monoglucosylated glycans, similarly to CNX derived from other species, and accelerate the folding of G 1 M 9 GN 2 -ribonuclease (RNase) in vitro. For refolding experiments, a homogeneous monoglucosylated high-mannose-type glycoprotein G 1 M 9 GN 2 -RNase was chemoenzymatically synthesized from G 1 M 9 GN-oxazoline and GN-RNase. Denatured G 1 M 9 GN 2 -RNase was refolded with highest efficiency in the presence of both soluble form of AoCNX and TigA. TigA contains two thioredoxin domains with CGHC motif, mutation analysis of which revealed that the one in N-terminal regions is involved in binding to AoCNX, while the other in catalyzing protein refolding. The results suggested that in glycoprotein folding process of A. oryzae , TigA plays a similar role as ERp57 in mammalian cells, as a partner protein of AoCNX.

Description: Accumulating evidence has suggested that cancer stem cells (CSCs) are at the root of drug resistance, and recent studies have indicated that caveolin-1, a membrane transporter protein, is involved in the regulation of cancer chemoresistance and stem cell signaling. However, the current understanding of the role of caveolin-1 in breast cancer development remains controversial. Herein, we demonstrate that caveolin-1 expression was upregulated after breast cancer chemotherapy in vitro and in vivo , accompanied by co-overexpression of β-catenin and ATP-binding cassette subfamily G member 2 (ABCG2) signaling. Additionally, breast CSCs were enriched for caveolin-1 expression. Caveolin-1 silencing sensitized breast CSCs by limiting their self-renewal ability but promoting the differentiation process. β-catenin silencing prevented the enhanced chemoresistance of CSCs induced by caveolin-1 overexpression, indicating that β-catenin is an essential molecule responsible for caveolin-1-mediated action. Further mechanistic investigation revealed that caveolin-1 silencing could downregulate the β-catenin/ABCG2 pathway through glycogen synthase kinase 3 beta activation and Akt inhibition, resulting in increased β-catenin phosphorylation and proteasomal degradation. Clinical investigation also revealed a close correlation between caveolin-1 and β-catenin/ABCG2 signaling in breast cancer samples. Notably, caveolin-1 was highly elevated in triple-negative breast cancer, and caveolin-1 silencing significantly impaired the tumorigenicity and chemoresistance of breast CSCs in in vivo models. Overall, our study not only highlights the role of caveolin-1 in mediating the chemoresistance of breast CSCs via β-catenin/ABCG2 regulation but also provides novel approaches for future therapies targeting CSCs.

Description: BACKGROUND Hypertensive retinal microvascular abnormalities include an increased retinal vein-to-artery diameter ratio. Because central retinal vein pressure depends on cerebrospinal fluid pressure (CSFP), we examined whether the retinal vein-to-artery diameter ratio and other retinal hypertensive signs are associated with CSFP. METHODS Participants of the population-based Beijing Eye Study (n = 1,574 subjects) underwent measurement of the temporal inferior and superior retinal artery and vein diameter. CSFP was calculated as 0.44 x body mass index (kg/m 2 ) + 0.16 x diastolic blood pressure (mm Hg) – 0.18 x age (years) – 1.91. RESULTS Larger retinal vein diameters and higher vein-to-artery diameter ratios were significantly associated with higher estimated CSFP ( P = 0.001) in multivariable analysis. In contrast, temporal inferior retinal arterial diameter was marginally associated ( P = 0.03) with estimated CSFP, and temporal superior artery diameter was not significantly associated ( P = 0.10) with estimated CSFP; other microvascular abnormalities, such as arteriovenous crossing signs, were also not significantly associated with estimated CSFP. In a reverse manner, higher estimated CSFP as a dependent variable in the multivariable analysis was associated with wider retinal veins and higher vein-to-artery diameter ratio. In the same model, estimated CSFP was not significantly correlated with retinal artery diameters or other retinal microvascular abnormalities. Correspondingly, arterial hypertension was associated with retinal microvascular abnormalities such as arteriovenous crossing signs ( P = 0.003), thinner temporal retinal arteries ( P 〈 0.001), higher CSFP ( P 〈 0.001), and wider retinal veins ( P = 0.001) or, as a corollary, with a higher vein-to-artery diameter ratio in multivariable analysis. CONCLUSIONS Wider retinal vein diameters are associated with higher estimated CSFP and vice versa. In arterial hypertension, an increased retinal vein-to-artery diameter ratio depends on elevated CSFP, which is correlated with blood pressure.