New experimental platform to study high density laser-compressed matter

We have developed a new experimental platform at the Linac Coherent Light Source (LCLS) which combines simultaneous angularly and spectrally resolved x-ray scattering measurements. This technique offers a new insights on the structural and thermodynamic properties of warm dense matter. The < 50 fs temporal duration of the x-ray pulse provides near instantaneous snapshots of the dynamics of the compression. We present a proof of principle experiment for this platform to characterize a shock-compressed plastic foil. We observe the disappearance of the plastic semi-crystal structure and the formation of a compressed liquid ion-ion correlation peak. The plasma parameters of shock-compressed plastic can be measured as well, but requires an averaging over a few tens of shots.

Exploring Mbar shock conditions and isochorically heated aluminum at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (invited)

Recent experiments performed at the Matter in Extreme Conditions end station of the Linac Coherent Light Source (LCLS) have demonstrated the first spectrally resolved measurements of plasmons from isochorically heated aluminum. The experiments have been performed using a seeded 8-keV x-ray laser beam as a pump and probe to both volumetrically heat and scatter x-rays from aluminum. Collective x-ray Thomson scattering spectra show a well-resolved plasmon feature that is down-shifted in energy by 19 eV. In addition, Mbar shock pressures from laser-compressed aluminum foils using velocity interferometer system for any reflector have been measured. The combination of experiments fully demonstrates the possibility to perform warm dense matter studies at the LCLS with unprecedented accuracy and precision.

Risk factors of venous thrombosis in patients with ankle fractures

AIM

Deep vein thrombosis (DVT) is a major complication that can occur after injuries. our aim was to explore the incidence and risk factors of venous thromboembolism in patients with ankle fractures.

METHODS

Consecutive patients with an isolated fracture of the ankle presenting at our centre between Sept 2004 and May 2012 were studied. They were investigated for venous thrombosis by Doppler sonography (DUS) before surgery. Univariate and multivariate logistic regressions analyses were performed to identify the incidence and risk factors for venous thromboembolism.

RESULTS

A total of 2347 patients were studied in the research. Of these, only 119 patients suffered from DVT. The multivariable analyses showed that diabetes, less activity and the time from injury were the key risk factors for thrombosis.

CONCLUSION

In patients with ankle fracture, the risk of thrombosis was low and it may not need warrant routine thromboprophylaxis. However, most cases had no significant symptoms, is necessary to grasp the indications for high risk patients to reduce the incidence rate of venous thrombosis.

Crosstalk between protective autophagy and NF-κB signal in high glucose-induced podocytes

Despite a great deal of recent studies focused on the pivotal role of autophagy in maintaining podocyte energy homeostasis, the mechanisms of autophagy in regulating transcriptional factors under high glucose (HG) condition are not fully understood. Here, we evaluated the effect of HG on nuclear factor-kappa B (NF-κB) signaling and autophagic process. The results showed that HG promoted autophagy in podocytes. Bafilomycin A1 (Baf A1) further enhanced this effect, but 3-methyadenine (3-MA) inhibited it. The proautophagic effects of HG manifested in the form of enhanced podocyte expression of light chain 3 (LC3)-II. In these cells, blockade of NF-κB signal by ammonium pyrrolidinethiocarbamate constrained in effectively reducing LC3-II up-regulation and increasing podocyte apoptosis. Furthermore, the autophagy inhibitors, such as Baf A1 and 3-MA, significantly enhanced HG-induced NF-κB activation and increased apoptosis. Thus, we conclude that the accumulation of autophagosomes results from enhancement of the autophagic flux, but not the blockage of autophagosome-lysosome fusion by HG. We also prove that HG-induced apoptosis, autophagy, and NF-κB signal are in a close crosstalk through a yet undetermined mechanism in podocytes.

MRI evaluation of BBB disruption after adjuvant AcSDKP treatment of stroke with tPA in rat

The primary limitation of thrombolytic treatment of ischemic stroke with tissue plasminogen activator (tPA) is the hemorrhagic risk. We tested AcSDKP (N-acetyl-seryl-aspartyl-lysyl-proline), as an auxiliary therapeutic agent, to reduce blood-brain barrier (BBB) disruption in a combination tPA thrombolytic treatment of stroke. Wistar rats subjected to embolic stroke were randomly assigned to either the tPA monotherapy group (n=9) or combination of tPA and AcSDKP treatment group (n=9) initiated at 4 h after ischemia. Magnetic resonance imaging (MRI) measurements were performed before and after the treatments. Immunohistochemical staining and measurements were performed to confirm MRI findings. Longitudinal MRI permeability measurements with gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) demonstrated that combination treatment of acute embolic stroke with AcSDKP and tPA significantly reduced BBB leakage, compared to tPA monotherapy, at 3 and 6 days (18.3±9.8 mm3 vs. 65.0±21.0 mm3, p<0.001) after the onset of stroke, although BBB leakage was comparable between the two groups prior to the treatments (6.8±4.4 mm3 vs. 4.3±3.3 mm3, p>0.18). The substantial reduction of BBB leakage observed in the combination treatment group was closely associated with reduced ischemic lesions measured by T2 maps (113.6±24.9 mm3 vs. 188.1±60.8 mm3, p<0.04 at 6 days). Histopathological analysis of the same population of rats showed that the combination treatment significantly reduced parenchymal fibrin deposition (0.063±0.059 mm2 vs. 0.172±0.103 mm2, p<0.03) and infarct volume (146.7±35.9 mm3 vs. 199.3±60.4 mm3, p<0.05) compared to the tPA monotherapy at 6days after stroke. MRI provides biological insight into the therapeutic benefit of combination treatment of stroke with tPA and AcSDKP 4h after onset, and demonstrates significantly improved cerebrovascular integrity with neuroprotective effects compared with tPA monotherapy.

Failure analysis of the ball bearings of dental air turbine handpieces

BACKGROUND

The aim of this study was to identify the nature and causes of deterioration and failure in dental handpiece ball bearings and thus provide guidance for clinical handling for service longevity.

METHODS

The bearings of 36 turbine assemblies were dismantled for visual inspection, documented using a digital camera, and examined using scanning electron microscopy, as appropriate.

RESULTS

For the metal parts of the ball bearing assembly, defects observed were mainly wear arising from the running load and corrosion. This was in the form of scratches and discoloured circumferential bands on the balls, and dull or worn surfaces extending around the circumference of the raceways. Cage damage including cracking, fracture, surface rubbing and distortion occurred, in varying degrees, in every failed turbine.

CONCLUSIONS

Dental ball bearing failure modes have been identified. Cumulative effects of damage from corrosion and mechanical factors lead to handpiece deterioration. The cage was found to be very vulnerable to damage, and this may be the key limitation on bearing lifetime. Autoclaving may contribute to that, as it does to corrosion in the absence of adequate lubrication, but this seems to be minor in comparison to the effects of abuse. There is no justification for failing to observe usage and sterilization instructions.

A Biomimetic Collagen-Apatite Scaffold with a Multi-Level Lamellar Structure for Bone Tissue Engineering

Collagen-apatite (Col-Ap) scaffolds have been widely employed for bone tissue engineering. We fabricated a Col-Ap scaffold with a unique multi-level lamellar structure consisting of co-aligned micro and macro pores. The basic building blocks of this scaffold are bone-like mineralized collagen fibers developed via a biomimetic self-assembly process in a collagen-containing modified simulated body fluid (m-SBF). This biomimetic method preserves the structural integrity and great tensile strength of collagen by reinforcing the collagen hydrogel with apatite nano-particles. Unidirectional aligned macro pores with a size of 63.8 to 344 μm are created by controlling the freezing rate and direction. The thickness of Col-Ap lamellae can be adjusted in the range 3.6 to 23 μm depending on the self-compression time. Furthermore, the multi-level lamellar structure has led to a twelve-fold increase in Young's modulus and a two-fold increase in the compression modulus along the aligned direction compared to a scaffold of the same composition with an isotropic equiaxed pore structure. Moreover, this novel lamellar scaffold supports the attachment and spreading of MC3T3-E1osteoblasts. Therefore, owing to the biomimetic composition, tunable structure, improved mechanical strength, and good biocompatibility of this novel scaffold, it has great potential to be used in bone tissue engineering applications.

MicroRNA-21 regulates T-cell apoptosis by directly targeting the tumor suppressor gene Tipe2

MicroRNAs (MiRs) are short noncoding RNAs that can regulate gene expression. It has been reported that miR-21 suppresses apoptosis in activated T cells, but the molecular mechanism remains undefined. Tumor suppressor Tipe2 (or tumor necrosis factor-α-induced protein 8 (TNFAIP8)-like 2 (TNFAIP8L2)) is a newly identified anti-inflammatory protein of the TNFAIP8 family that is essential for maintaining immune homeostasis. We report here that miR-21 is a direct target of nuclear factor-κB and could regulate Tipe2 expression in a Tipe2 coding region-dependent manner. In activated T cells and macrophages, Tipe2 expression was markedly downregulated, whereas miR-21 expression was upregulated. Importantly, Tipe2-deficient T cells were significantly less sensitive to apoptosis. Conversely, overexpression of Tipe2 in EL-4 T cells increased their susceptibility to activation-induced apoptosis. Therefore, Tipe2 provides a molecular bridge between miR-21 and cell apoptosis; miR-21 suppresses apoptosis in activated T cells at least in part through directly targeting tumor suppressor gene Tipe2.

Multiple amino acid mutations in viral RNA polymerase may synergistically enhance the transmissibility and/or virulence of the 2009 pandemic influenza (H1N1) virus

Influenza viruses may change their transmissibility and virulence via single or multiple point mutations in the functional regions of their structural proteins. In this study, we compared sequences of all three subunits of viral RNA polymerase, i.e. PA, PB1 and PB2, of the 2009 pandemic influenza A (H1N1) virus isolates from different stages of the pandemic and found that the frequencies of three mutations, including V14I and K716Q in PA and K736G in PB1, showed a similar trend. Interestingly, the death rate of infected patients during the pandemic matched the frequency of the three mutations with a 2-months delay. These findings suggest that the combined mutations may have acted synergistically in enhancing the transmissibility and/or virulence of the 2009 pandemic virus. If definitely proved, this hypothesis could guide the rational design of antiviral therapeutics targeting the RNA polymerase of influenza viruses.

Neotyphodium coenophialum-infected tall fescue and its potential application in the phytoremediation of saline soils

The growth response of endophyte-infected (EI) and endophyte-free (EF) tall fescue to salt stress was investigated under two growing systems (hydroponic and soil in pots). The hydroponic experiment showed that endophyte infection significantly increased tiller and leaf number, which led to an increase in the total biomass of the host grass. Endophyte infection enhanced Na accumulation in the host grass and improved Na transport from the roots to the shoots. With a 15 g l(-1) NaCl treatment, the phytoextraction efficiency of EI tall fescue was 2.34-fold higher than EF plants. When the plants were grown in saline soils, endophyte infection also significantly increased tiller number, shoot height and the total biomass of the host grass. Although EI tall fescue cannot accumulate Na to a level high enough for it to be termed a halophyte, the increased biomass production and stress tolerance suggested that endophyte/plant associations had the potential to be a model for endophyte-assisted phytoextraction in saline soils.

Stimulated mast cells promote maturation of myocardial microvascular endothelial cell neovessels by modulating the angiopoietin-Tie-2 signaling pathway

Angiopoietin (Ang)-1 and Ang-2 interact in angiogenesis to activate the Tie-2 receptor, which may be involved in new vessel maturation and regression. Mast cells (MCs) are also involved in formation of new blood vessels and angiogenesis. The present study was designed to test whether MCs can mediate angiogenesis in myocardial microvascular endothelial cells (MMVECs). Using a rat MMVEC and MC co-culture system, we observed that Ang-1 protein levels were very low even though its mRNA levels were increased by MCs. Interestingly, MCs were able to enhance migration, proliferation, and capillary-like tube formation, which were associated with suppressed Ang-2 protein expression, but not Tie-2 expression levels. These MCs induced effects that could be reversed by either tryptase inhibitor [N-tosyl-L-lysine chloromethyl ketone (TLCK)] or chymase inhibitor (N-tosyl-L-phenylalanyl chloromethyl ketone), with TLCK showing greater effects. In conclusion, our data indicated that MCs can interrupt neovessel maturation via suppression of the Ang-2/Tie-2 signaling pathway.

The prevalence of isolated calf deep vein thrombosis in patients with pulmonary embolism

AIM

Due to discordant results, the risk of isolated calf deep vein thrombosis (DVT) -associated pulmonary embolism (PE) is not well established. This study aimed to detect the prevalence of isolated calf DVT in patients with PE, discussing the importance of isolated calf DVT.

METHODS

We retrospectively reviewed all the inpatients that were both diagnosed PE and DVT between November 2002 and February 2010 in our hospital, analyzed the prevalence of isolated calf DVT and the relevance details.

RESULTS

Among all the 63 patients who were diagnosed both PE and DVT, isolated calf DVT was detected in 23 limbs in 16 patients (16/63=25.4%). Soleal vein was the most frequently involved, with 14 limbs. Ten of the patients had low risk PE, 3 had submassive PE and 3 had massive PE. In the 6 patient who had submassive and massive PE, 4 had bilateral leg calf DVT and all 6 were multiple calf vein involvement.

CONCLUSION

Our results reflected the prevalence of PE at presentation, which was high and included severe cases. Though, as reported, PE during surveillance was the most precisely way to reflect PE in isolated calf DVT, but such a risk of PE at presentation should not just be ignored and its importance still needs to be discussed. Well-designed and adequately powered studies are needed to give strong evidence to recognize the real risk of isolated calf DVT, either at presentation or at surveillance, to distinguish the one with high risk and determine appropriate way to treat it.

Attenuation of allergic airway inflammation in a murine model of asthma by Licochalcone A

CONTEXT

Licochalcone A (Lico A) is a major and biogenetically characteristic chalcone isolated from the root of Xinjiang liquorice, Glycyrrhiza inflata.

OBJECTIVE

We focused on investigating whether Lico A possesses distinct anti-inflammatory activity on a non-infectious mouse model of asthma, and we aimed to elucidate its involvement with the mitogen-activated protein kinases pathway.

METHODS

BALB/c mice that were sensitized and challenged to ovalbumin (OVA) were treated with Lico A (50 mg/kg) 1 h before they were challenged with OVA.

RESULTS

Our study demonstrated that Lico A may effectively inhibit the increase in T-helper type 2 cytokines, such as interleukin (IL)-4, IL-5 and IL-13 in bronchoalveolar lavage fluid, and reduced serum levels of OVA-specific IgE and IgG. Furthermore, Lico A substantially inhibited OVA-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. Meanwhile, pretreatment with Lico A resulted in a significant reduction in mRNA expression of acidic mammalian chitinase, chitinase 3-like protein 4 (Ym2), E-selectin, Muc5ac, CCL11 and CCR3 in lung tissues and airway hyper-responsiveness to methacholine.

CONCLUSIONS

These findings suggest that Lico A may effectively delay the progression of airway inflammation and could be used as a therapy for patients with allergic airway inflammation.

Upregulated Hoxc6 expression is associated with poor survival in gastric cancer patients

Human Hox genes (Homeobox) have crucial roles in development and differentiation, regulating numerous processes including apoptosis, receptor signalling, differentiation, motility and angiogenesis. Aberrant expression of Hoxc6 gene has been reported in several tumor tissues and cancer cell lines. The prognostic significance of Hoxc6 in gastric cancer remains largely unknown.This study was aimed to investigate the clinical significance of Hoxc6 in gastric cancer.Total RNA of paired tissue samples (n=25) and a tissue microarray containing 161 paired tissues from patients with gastric cancers at different stages were collected. Quantitative real-time PCR and immunochemistry assay were carried out to investigate the expression of Hoxc6. Hoxc6 mRNA was increased in gastric cancer tissues ( 16 of 25) compared with the adjacent normal mucosa (P<0.05). Immunohistochemical detection showed that expression of Hoxc6 was associated with the depth of tumor invasion (P<0.05). Patients with higher expression levels of Hoxc6 had a shorter overall survival rate (P<0.05).Hoxc6 might contribute to the progression of gastric carcinogenesis and may be a significant predictor of poor survival in patients with gastric cancer after curative operations.