Improved upper limits on the stochastic gravitational-wave background from 2009-2010 LIGO and Virgo data

Gravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of Ω_{GW}(f)=Ω_{α}(f/f_{ref})^{α}, we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of α=0, we constrain the energy density of the stochastic background to be Ω_{GW}(f)<5.6×10^{-6}. For the 600-1000 Hz band, Ω_{GW}(f)<0.14(f/900  Hz)^{3}, a factor of 2.5 lower than the best previously reported upper limits. We find Ω_{GW}(f)<1.8×10^{-4} using a spectral index of zero for 170-600 Hz and Ω_{GW}(f)<1.0(f/1300  Hz)^{3} for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.

MicroRNA-30d regulates cardiomyocyte pyroptosis by directly targeting foxo3a in diabetic cardiomyopathy

Diabetic cardiomyopathy is a common cardiac condition in patients with diabetes mellitus, which can result in cardiac hypertrophy and subsequent heart failure, associated with pyroptosis, the pro-inflammatory programmed cell death. MicroRNAs (miRNAs), small endogenous non-coding RNAs, have been shown to be involved in diabetic cardiomyopathy. However, whether miRNAs regulate pyroptosis in diabetic cardiomyopathy remains unknown. Our study revealed that mir-30d expression was substantially increased in streptozotocin (STZ)-induced diabetic rats and in high-glucose-treated cardiomyocytes as well. Upregulation of mir-30d promoted cardiomyocyte pyroptosis in diabetic cardiomyopathy; conversely, knockdown of mir-30d attenuated it. In an effort to understand the signaling mechanisms underlying the pro-pyroptotic property of mir-30d, we found that forced expression of mir-30d upregulated caspase-1 and pro-inflammatory cytokines IL-1β and IL-18. Moreover, mir-30d directly repressed foxo3a expression and its downstream protein, apoptosis repressor with caspase recruitment domain (ARC). Furthermore, silencing ARC by siRNA mimicked the action of mir-30d: upregulating caspase-1 and inducing pyroptosis. These findings promoted us to propose a new signaling pathway leading to cardiomyocyte pyroptosis under hyperglycemic conditions: mir-30d↑→foxo3a↓→ ARC↓→caspase-1↑→IL-1β, IL-18↑→pyroptosis↑. Therefore, mir-30d may be a promising therapeutic target for the management of diabetic cardiomyopathy.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

Note: a Piezo Tip/Tilt Platform: structure, kinematics, and experiments

A Piezo Tip/Tilt Platform (PT(2)P) is presented with its structure, kinematics, and preliminary experiments. Two essential models of the presented PT(2)P, an equivalent hinge of the flexure hinge and a simplified model of the transmission mechanism, are discussed with the analysis on the structure of the PT(2)P. Based on these models, the inverse kinematics of the PT(2)P is derived. Two experiments are conducted on a prototype of the PT(2)P. The kinematic model is verified with experimental results, which also indicate that the resolution and the repeatability of the PT(2)P is, respectively, better than 0.50 μrad and 0.25 μrad.

Correlation between the severity of periodontitis and coronary artery stenosis in a Chinese population

BACKGROUND

The aim of this study was to evaluate the relationship between the severity of periodontitis and the extent and degree of coronary artery stenosis in a Chinese population.

METHODS

Patients (n = 853) with coronary artery stenosis confirmed by coronary angiography were eligible to take part in the study. Only subjects that were ≥60 years old, had ≥50% stenosis in at least one coronary artery, and did not have diabetes or a history of smoking were included (n = 115). After periodontal examination, including bleeding index, probing depth calculus index, plaque index and periodontal attachment loss, four groups were defined based on the severity of periodontitis: no periodontitis/gingivitis (M0, n = 19); mild periodontitis (M1, n = 27); moderate periodontitis (M2, n = 31); and severe periodontitis (M3, n = 38). The extent and degree of coronary artery stenosis was obtained by calculating the Gensini score (GS).

RESULTS

The GS was significantly greater in the M3 group compared with the M0 group. Multiple linear regression analysis revealed that probing depth and plaque index were significantly correlated with the GS.

CONCLUSIONS

The extent and severity of coronary artery stenosis in Chinese patients ≥60 years old is positively correlated with the severity of periodontitis.

Invasive neuroendocrine carcinoma of the breast: a prognostic research of 107 Chinese patients

Neuroendocrine carcinoma (NEC) of the breast, a distinct type of mammary carcinoma whose terminology was not proposed until 2003, has not been well recognized or studied. The aim of our study is to evaluate the clinicopathological features and outcomes of this type of tumor. We conducted a comparative study on 107 NEC patients and 475 invasive ductal carcinoma, not otherwise specified(IDC, NOS) patients from the Department of Pathology, Huashan Hospital, Fudan University, to determine the demographic, pathological, and clinical features at presentation, along with patient outcomes and prognostic factors. With an older age at presentation, NECs are more likely to be estrogen receptor(ER)/ progesterone receptor (PR) positive and human epidermal growth factor receptor 2 (HER-2) negative, and have a higher propensity for local recurrence and poorer overall survival(OS). Higher T classification, M classification, TNM stage, the expression of Ki67, and the absence of PR expression are prognostically of poorer OS and distant recurrence-free survival(DRFS). Distant metastasis is also a dependent prognostic factor. NEC of the breast is a distinct type of neoplasm with higher malignancy. Novel therapies such as the endocrine therapy should be explored and studies with larger case number and longer follow-up will be needed.

One-step Preparation of Comb-like Surfactants Containing Poly(ethylene oxide) Methyl Ether and Linear Alkyl Grafts

The optimum one-step method for preparing comb-like surfactants with poly(styrene-co-maleic anhydride) (SMA) as backbone was investigated to achieve a commercial way for manufacture. The side chain molecule was introduced into reaction system while the radical copolymerization of styrene (St) and maleic anhydride (MA) in anhydrous inhibitor-free tetrahydrofuran (THF) was finished. The precipitation and purification process of SMA in traditional grafting-onto route was passed over. A series comb-like surfactants with various side chain, poly(styrene-co-maleic anhydride)-g-(poly(ethylene glycol) monomethyl ether) (SMA-M), poly(styrene-co-maleic anhydride)-g-(poly(ethylene glycol) monomethyl ether & dodecane) (SMA-M+C12) and poly(styrene-co-maleic anhydride)-g-(dodecane) (SMA-C12), was prepared via this one step method respectively. The molecular weight of the products was measurement via gel permeation chromatography (GPC). The comb-like structures of the surfactants were confirmed by Infrared Spectroscopy (IR) and 1H nuclear magnetic resonance spectroscopy (1H NMR). The equilibrium surface tension was measured to evaluate the surface activity of comb-like surfactants. The surface activity of the product could be improved by using C12 to carry out a hydrophobic modification. The surface activity of comb-like surfactants could be adjusted by using various side chains with different amphiphilic property.

Complications of thermal ablation of hepatic tumours: comparison of radiofrequency and microwave ablative techniques

AIM

To investigate the common complications of thermal ablation of liver tumours using both radiofrequency ablation (RFA) and microwave ablation (MWA) techniques, and to compare the safety of these two procedures.

MATERIALS AND METHODS

This retrospective study protocol was approved by the institution's ethics committee to allow investigators to review existing patient medical records. A total of 879 patients with hepatic tumours underwent thermal ablation; 323 patients underwent RFA and 556 underwent MWA. The complications of the RFA and MWA techniques were compared.

RESULTS

A total of 1030 thermal ablation sessions was performed in 879 patients with a total of 1652 tumours. Three hundred and twenty-three patients with 562 tumours received a total of 376 RFA sessions with an average of 1.16 ± 0.48 sessions per patient. The other 556 patients with 1090 tumours received a total of 654 MWA with an average 1.18 ± 0.51 sessions per patient. The mortality rates were 0.31% (1/323) and 0.36% (2/556) in RFA and MWA group. In RFA and MWA group, the major complication rates were 3.5% (13/376) and 3.1% (20/654), meanwhile the minor complication rates were 5.9% (22/376) and 5.7% (37/654). There was no statistically significant difference in the mortality rates, major complications, and minor complications between the RFA and MWA groups (p > 0.05).

CONCLUSIONS

Thermal ablation therapy in the treatment of liver cancers is relatively safe with low mortality and a low incidence of serious complications. The types and incidences of complications caused by RFA and MWA are similar and comparable for safety consideration in clinical settings.

Effects of telomerase activity and apoptosis on ex vivo expansion of cord blood CD34(+) cells

OBJECTIVE

Ex vivo expansion of CD34(+) cells has become critically important in order to obtain sufficient haematopoietic stem cells for clinical application. Among major regulators involved in ex vivo expansion, telomerase activity and apoptosis have been revealed to be closely linked to cell cycle progression. However, all exact roles remain to be elucidated. Here, change in telomerase activity and level of apoptosis in cord blood (CB) CD34(+) cells were evaluated together with specific cell population growth rate during ex vivo culture.

MATERIALS AND METHODS

CD34(+) cells isolated from human CB were expanded ex vivo over a 28-day period. Besides monitoring cell proliferation kinetics of the CD34(+) cells, changes in telomerase activity and apoptotic levels were investigated. Several relevant genes were quantified by qRT-PCR during the culture period.

RESULTS

Significant elevation of telomerase activity had close relationship to activation of CB CD34(+) cell expansion. Peak apoptotic level was accompanied by a remarkable decline in cell-specific growth rate, and apoptotic level of differentiated CD34(-) population was significantly higher than that of the CD34(+) population.

CONCLUSION

Although telomerase activity was activated during the culture, expansion of CB CD34(+) cells seemed to be more susceptible to apoptotic suppression when cultured ex vivo, which implied that apoptosis may serve as a rate-limiting factor involved in controlling expansion efficiency.

Protective effect of Clostridium tyrobutyricum in acute dextran sodium sulphate-induced colitis: differential regulation of tumour necrosis factor-α and interleukin-18 in BALB/c and severe combined immunodeficiency mice

One of the promising approaches in the therapy of ulcerative colitis is administration of butyrate, an energy source for colonocytes, into the lumen of the colon. This study investigates the effect of butyrate producing bacterium Clostridium tyrobutyricum on dextran sodium sulphate (DSS)-induced colitis in mice. Immunocompetent BALB/c and immunodeficient severe combined immunodeficiency (SCID) mice reared in specific-pathogen-free (SPF) conditions were treated intrarectally with C. tyrobutyricum 1 week prior to the induction of DSS colitis and during oral DSS treatment. Administration of DSS without C. tyrobutyricum treatment led to an appearance of clinical symptoms - bleeding, rectal prolapses and colitis-induced increase in the antigen CD11b, a marker of infiltrating inflammatory cells in the lamina propria. The severity of colitis was similar in BALB/c and SCID mice as judged by the histological damage score and colon shortening after 7 days of DSS treatment. Both strains of mice also showed a similar reduction in tight junction (TJ) protein zonula occludens (ZO)-1 expression and of MUC-2 mucin depression. Highly elevated levels of cytokine tumour necrosis factor (TNF)-α in the colon of SCID mice and of interleukin (IL)-18 in BALB/c mice were observed. Intrarectal administration of C. tyrobutyricum prevented appearance of clinical symptoms of DSS-colitis, restored normal MUC-2 production, unaltered expression of TJ protein ZO-1 and decreased levels of TNF-α and IL-18 in the descending colon of SCID and BALB/c mice, respectively. Some of these features can be ascribed to the increased production of butyrate in the lumen of the colon and its role in protection of barrier functions and regulation of IL-18 expression.