361 research outputs found
Roche Lobe Shapes for testing MOND-like Modified Gravity
Dark Matter (DM) theories and mass-tracing-light theories like MOND are by
construction nearly degenerate on galactic scales, but not when it comes to the
predicted shapes of Roche Lobes of a two-body system (e.g., a globular cluster
orbiting a host galaxy). We show that the flattening of the Roche lobe is
sensitive to the function mu(g) in modification of the law of gravity. We
generalise the analytical results obtained in the deep-MOND limit by Zhao
(2005, astro-ph/0511713 and astro-ph/0512425), and consider a binary in the
framework of a MOND-like gravity modification function mu(g) or a general
non-Keplerian gravity g \propto R^-\zeta. We give analytical expressions for
the inner Lagrange point and Robe lobe axis ratios. The Roche lobe volume is
proven to scale linearly with the true mass ratio, which applies to any mu(g),
hence mass-tracing light models would overpredict the Roche lobe of a DM-poor
globular cluster in a DM-rich host galaxy, and underpredict the size of a
DM-richer dwarf satellite. The lobes are squashed with the flattening ~ 0.4 in
the strong gravity and ~ 0.6 in the weak gravity; a precise measurement of the
flattening could be used to verify the anisotropic dilation effect which is
generic to MOND-like gravity. We generalise these results for extended mass
distribution, and compare predicted Roche radii in different gravity theories
with limiting radii of observed globular clusters and dwarf galaxy satellites.Comment: 11p, 7 figs, accepted for Astronomy and Astrophysic
Optimum Combination of Insulin-Transferrin-Selenium and Fetal Bovine Serum for Culture of Rabbit Articular Chondrocytes in Three-Dimensional Alginate Scaffolds
Fetal bovine serum (FBS) has been reported to affect chondrocyte biosynthesis in monolayer culture. Insulin-Transferrin-Selenium (ITS) was investigated as a partial replacement for FBS during in vitro culture of rabbit articular chondrocytes in three-dimensional alginate scaffold. Chondrocyte-seeded alginate hydrogels were cultured in Dulbecco's modified Eagle's medium plus 10% FBS, 1% ITS plus 2% FBS, 1% ITS plus 4% FBS, or 1% ITS plus 8% FBS. At designed time point, the Chondrocyte-seeded alginate hydrogels were harvested and evaluated with histological staining, immunohistochemistry, and quantitative gene expression analysis. Viable cell density and cell division were also evaluated. Chondrocytes biosynthesis and cell division in 1% ITS with 2% FBS medium were similar to that in medium added with 10% FBS. For a total culture of 3 weeks, phenotypic gene expression in chondrocyte-seeded hydrogels was maintained at high levels in medium with 1% ITS plus 2% FBS, while it was decreased to varying degrees in the other groups. In conclusion, with 1% ITS, medium with 2% FBS could promote chondrocyte biosynthesis and cell division, and prevented cell dedifferentiation in three-dimensional alginate scaffolds
On the exponential convergence of input-output signals of nonlinear feedback systems
We show that the integral-constraint-based robust feedback stability theorem
for certain Lurye systems exhibits the property that the endogenous
input-output signals enjoy an exponential convergence rate for all initial
conditions of the linear time-invariant subsystem. More generally, we provide
conditions under which a feedback interconnection of possibly open-loop
unbounded subsystems to admit such an exponential convergence property, using
perturbation analysis and a combination of tools including integral quadratic
constraints, directed gap measure, and exponential weightings. As an
application, we apply the result to first-order convex optimisation methods. In
particular, by making use of the Zames-Falb multipliers, we state conditions
for these methods to converge exponentially when applied to strongly convex
functions with Lipschitz gradients.Comment: This paper has been submitted to Automatic
Controlled release of paclitaxel from a self-assembling peptide hydrogel formed in situ and antitumor study in vitro
Background: A nanoscale injectable in situ-forming hydrogel drug delivery system was developed in this study. The system was based on a self-assembling peptide RADA16 solution, which can spontaneously form a hydrogel rapidly under physiological conditions. We used the RADA16 hydrogel for the controlled release of paclitaxel (PTX), a hydrophobic antitumor drug.
Methods: The RADA16-PTX suspension was prepared simply by magnetic stirring, followed by atomic force microscopy, circular dichroism analysis, dynamic light scattering, rheological analysis, an in vitro release assay, and a cell viability test.
Results: The results indicated that RADA16 and PTX can interact with each other and that the amphiphilic peptide was able to stabilize hydrophobic drugs in aqueous solution. The particle size of PTX was markedly decreased in the RADA16 solution compared with its size in water. The RADA16-PTX suspension could form a hydrogel in culture medium, and the elasticity of the hydrogel showed a positive correlation with peptide concentration. In vitro release measurements indicated that hydrogels with a higher peptide concentration had a longer half-release time. The RADA16-PTX hydrogel could effectively inhibit the growth of the breast cancer cell line, MDA-MB-435S, in vitro, and hydrogels with higher peptide concentrations were more effective at inhibiting tumor cell proliferation. The RADA16-PTX hydrogel was effective at controlling the release of PTX and inhibiting tumor cell growth in vitro.
Conclusion: Self-assembling peptide hydrogels may work well as a system for drug delivery
Industry-finance integration activities is beneficial to the improvement of business performance of fishery companies—Based on DEA-CCR Model and DEA-Malmquist Model
Fisheries are an essential component of the national economy. The evaluation of fishery enterprises' business performance helps reveal the fishery industry's operating efficiency and serve the fishery economy's sustainable and high-quality development. This study used the data of fishery companies with industry-finance integration on the stock market from 2012-2021 and conducted a comparative study on the business performance of fishery companies with industry-finance integration on the stock market based on the DEA-CCR model and DEA- Malmquist index method. Two main results were revealed (i) the integration of industry and finance was an effective means to improve business performance, and the financial gains from the integration of industry and finance by listed fishery companies improve the overall efficiency and total factor productivity (TFP) of enterprises. (ii) The average TFP of listed fishery companies in China is declining, and technological decline is the main reason for the decline in TFP
The Effect of Different Laser Irradiation on Cyclophosphamide-Induced Leucopenia in Rats
Objective. To assess the effect of different lasers on cyclophosphamide- (CTX-) induced leucopenia in rats. Methods. 11 rats were normal control and 55 rats were injected with a dose of 80 mg/kg CTX for the first time and 40 mg/kg on the 6th and the 11th days to establish a leucopenia model. Rats of the irradiation groups received a 5-minute laser irradiation with either single 10.6 μm or 650 nm laser or alternatively 10.6 μm–650 nm laser irradiation, besides a sham treatment on acupoint Dazhui (DU 14) and acupoint Zusanli (ST 36) of both sides, 8 times for 16 days. Normal and model control group received no treatment. Results. On day 16 after the first CTX injection, the WBC counts from all the laser irradiation groups were significantly higher than those from the model control and the sham group (P<0.05), while there were no significant differences compared with the normal control (P>0.05). The TI of 10.6 μm–650 nm laser irradiation group was significantly higher than that of the model control group (P<0.05). Conclusions. The single and combined 10.6 μm and 650 nm laser irradiation on ST36 and DU14 accelerated the recovery of the WBC count in the rats with leucopenia
Four-channel coarse WDM for inter-and intra-satellite optical communications
Abstract A polymer volume grating-based four-channel coarse wavelength division multiplexer (WDM) for inter-and intra-satellite optical communication application is reported for the first time. This compact four-channel WDM device working at 0.83, 1.06, 1.34 and 1.55 mm is designed to build a complete optical link between two satellites, where wavelengths of 0.83 and 1.55 mm are used for data stream channels, 1.06 and 1.34 mm are used for inter-and intra-satellite connection. It is for the first time reported that a WDM device can cover such a large wavelength range in a single substrate. For transverse electric (TE) wave, the channel efficiencies at 0.83, 1.06, 1.34 and 1.55 mm are 55%, 40%, 35% and 45%, respectively. Channel efficiencies for transverse magnetic (TM) waves are 20% lower than those of TE waves on average. Wavelength shifts due to Doppler effect, temperature variations and radiation effects in space can be adequately accommodated. Published by Elsevier Ltd. Keywords: Wavelength division multiplexing; Satellite communication; Holographic gratings The concept of space-based, free space optical communications among satellites was developed in the early 1960s [1]. However, there was no system demonstration coming into reality until 2001 by ASTRIUM Coarse wavelength division multiplexing (WDM) technology, which is developed for storage access networks (SANs), finds its great potential for applications in the space-based optical communication system. The data bit-rate independence of the WDM technology ARTICLE IN PRESS www.elsevier.com/locate/optlastec 0030-3992/$ -see front matter Published by Elsevier Ltd
Associations of 10 dietary habits with breast cancer: a Mendelian randomization study
IntroductionEpidemiological studies have revealed a link between dietary habits and the breast cancer risk. The causality of the association between food consumption and breast cancer requires further investigation.MethodsUsing Mendelian randomization, we assessed the causal effects of 10 dietary habits on the risks of breast cancer and its subtypes (estrogen receptor [ER] + and ER- breast cancer). We obtained dietary pattern data in 2018 (number of single-nucleotide polymorphisms [SNPs] = 9,851,867) and breast cancer data in 2017 (number of SNPs = 10,680,257) from IEU OpenGWAS. Rigorous sensitivity analyses were conducted to ensure that the study results were credible and robust.ResultsWe identified that genetic predisposition to higher dried fruit intake was linked to a reduced risk of overall breast cancer (inverse variance-weighted [IVW] odds ratio [OR] = 0.55; 95% confidence interval [CI]: 0.43–0.70; p = 1.75 × 10−6), ER+ breast cancer (IVW OR = 0.62; 95% CI: 0.47–0.82; p = 8.96 × 10−4) and ER− breast cancer (IVW OR = 0.48; 95% CI: 0.34–0.68; p = 3.18 × 10−5), whereas genetic predisposition to more oily fish intake was linked to a lower risk of ER+ breast cancer (IVW OR = 0.73; 95% CI: 0.53–0.99; p = 0.04).DiscussionOur findings suggest that a genetic predisposition for dried fruit and oily fish consumption may be protective against breast cancer; however, further investigation is required
The relation between stellar mass and weak lensing signal around galaxies: Implications for MOND
We study the amplitude of the weak gravitational lensing signal as a function
of stellar mass around a sample of relatively isolated galaxies. This selection
of lenses simplifies the interpretation of the observations, which consist of
data from the Red- sequence Cluster Survey and the Sloan Digital Sky Survey. We
find that the amplitude of the lensing signal as a function of stellar mass is
well described by a power law with a best fit slope \alpha= 0.74 \pm 0.08. This
result is inconsistent with Modified Newtonian Dynamics, which predicts \alpha
= 0.5 (we find \alpha > 0.5 with 99.7% confidence). As a related test, we
determine the MOND mass-to-light ratio as a function of luminosity. Our results
require dark matter for the most luminous galaxies (L >=10^11 L_sun). We rule
out an extended halo of gas or active neutrinos as a way of reconciling our
findings with MOND. Although we focus on a single alternative gravity model, we
note that our results provide an important test for any alternative theory of
gravity.Comment: 10 pages, 6 figs, accepted by MNRA
Risk factors of oncogenic HPV infection in HIV-positive men with anal condyloma acuminata in Shenzhen, Southeast China: a retrospective cohort study
BackgroundHuman immunodeficiency virus (HIV)-positive patients with anal condyloma acuminata (CA) present an increased risk of anal cancer progression associated with oncogenic human papillomavirus (HPV) infection. It is essential to explore determinants of anal infection by oncogenic HPV among HIV-positive patients with CA.MethodsA retrospective cohort study was performed in HIV-positive patients with CA between January 2019 to October 2021 in Shenzhen, Southeast China. Exfoliated cells were collected from CA lesions and the anal canal of HPV genotypes detected by fluorescence PCR. Unconditional logistic regression analysis was used to probe associations of independent variables with oncogenic HPV infection.ResultsAmong HIV-positive patients with CA, the most prevalent oncogenic genotypes were HPV52 (29.43%), HPV16 (28.93%), HPV59 (19.20%), and HPV18 (15.96%). Risk of oncogenic HPV infection increased with age at enrollment (COR: 1.04, 95% CI: 1.01–1.07, p = 0.022). In the multivariable analysis, age ≥ 35 years (AOR: 2.56, 95% CI: 1.20–5.70, p = 0.02) and history of syphilis (AOR: 3.46, 95% CI: 1.90–6.79, p < 0.01) were independent risk factors statistically associated with oncogenic HPV infection. History of syphilis (AOR: 1.72, 95% CI: 1.08–2.73, p < 0.02) was also an independent risk factor statistically associated with HPV16 or HPV18 infection.ConclusionIn clinical practice, HIV-positive CA patients aged ≥35 years or with a history of syphilis should carry out HR-HPV testing and even anal cancer-related examinations to prevent the occurrence of anal cancer
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