Experimental demonstration of a slippage-dominant free-electron laser amplifier

We report the first experimental demonstration of a slippage-dominant free-electron laser (FEL) amplifier using a 140-fs full width at half maximum broadband seed laser pulse. The evolution of the longitudinal phase space of a laser seeded FEL amplifier in the slippage-dominant regime was experimentally characterized. We observed, for the first time, that the pulse duration of the FEL is primarily determined by the slippage between the seed laser and the electron beam. With a ± 1% variation in the electron-beam energy, we demonstrated reasonably good longitudinal coherence and a ± 2% spectral tuning range. The experimentally observed temporal and spectral evolution of the slippage-dominant FEL was verified by the numerical simulations.

Adsorption of copper(II) onto sewage sludge-derived materials via microwave irradiation

The materials with adsorbent properties were produced from urban sewage sludge by two different procedures via microwave irradiation: (1) by one single pyrolysis stage (SC); (2) by chemical activation with ZnCl(2) (SZ). The BET, SEM and FT-IR have been used to evaluate the pore structural parameters and surface chemistry of the adsorbents, respectively. Subsequently they were used for adsorption of Cu(II) from aqueous solutions. The effects of various experimental parameters, such as pH, temperature were investigated in a batch-adsorption technique. The results showed that the adsorption of Cu(II) was maximal at pH 5.0. The kinetic study demonstrated that the adsorption process was followed the second-order kinetic equation. The experimental adsorption isotherm data were well fitted with Langmuir model and the maximum adsorption capacity of Cu(II) were found to be 3.88 and 10.56 mg/g for SC and SZ, respectively, in the solution of pH 5.0. Thermodynamic parameters such as changes in the enthalpy (ΔH(0)), entropy (ΔS(0)) and free energy (ΔG(0)) indicate that Cu(II) adsorption onto SC and SZ is an endothermic and spontaneous process in nature at 15-45°C. These results indicate that the sewage sludge-derived material via microwave induced ZnCl(2) activation is an effective and alternative adsorbent for the removal of Cu(II) from aqueous solution.

The autophagic paradox in cancer therapy

Autophagy, hallmarked by the formation of double-membrane bound organelles known as autophagosomes, is a lysosome-dependent pathway for protein degradation. The role of autophagy in carcinogenesis is context dependent. As a tumor-suppressing mechanism in early-stage carcinogenesis, autophagy inhibits inflammation and promotes genomic stability. Moreover, disruption of autophagy-related genes accelerates tumorigenesis in animals. However, autophagy may also act as a pro-survival mechanism to protect cancer cells from various forms of cellular stress. In cancer therapy, adaptive autophagy in cancer cells sustains tumor growth and survival in face of the toxicity of cancer therapy. To this end, inhibition of autophagy may sensitize cancer cells to chemotherapeutic agents and ionizing radiation. Nevertheless, in certain circumstances, autophagy mediates the therapeutic effects of some anticancer agents. Data from recent studies are beginning to unveil the apparently paradoxical nature of autophagy as a cell-fate decision machinery. Taken together, modulation of autophagy is a novel approach for enhancing the efficacy of existing cancer therapy, but its Janus-faced nature may complicate the clinical development of autophagy modulators as anticancer therapeutics.

Ectopic study of tissue-engineered bone complex with enamel matrix proteins, bone marrow stromal cells in porous calcium phosphate cement scaffolds, in nude mice

OBJECTIVE

This study aimed to investigate the potential of enamel matrix proteins (EMPs) on promoting osteogenic differentiation of porcine bone marrow stromal cells (pBMSCs), as well as new bone formation capabilities, in a tissue-engineered bone complex scaffold of EMPs, pBMSCs and porous calcium phosphate cement (CPC).

MATERIALS AND METHODS

Effects of EMPs on pBMSCs in vitro was first determined by alkaline phosphatase (ALP) activity, von Kossa staining assay and mRNA expression of ALP, bone sialoprotein (BSP) and osteocalcin (OCN) genes. Next, an ectopic new bone formation test was performed in a nude mouse model with four groups: CPC scaffold alone; CPC scaffold + EMPs; CPC scaffold + pBMSCs; and CPC scaffold + EMPs + pBMSCs, for 2 or 4 weeks.

RESULTS

ALP activity, von Kossa assay and mRNA expressions of ALP, BSP and OCN genes were all significantly higher with 150 μg/ml EMP treatment in vitro. In nude mice, new bone formation was detected only in the CPC scaffold + EMPs + pBMSCs group at 2 weeks. At 4 weeks, in the tissue-engineered construct there was significantly higher bone formation ability than other groups.

CONCLUSIONS

EMPs promoted osteogenic differentiation of pBMSCs, and the tissue-engineered complex of EMPs, pBMSCs and CPC scaffold may be a valuable alternative to be used in periodontal bone tissue engineering and regeneration.

Birth weight and subsequent risk of obesity: a systematic review and meta-analysis

This report describes the association between birth weight (BW) and obesity. Screening of 478 citations from five electronic databases resulted in the inclusion of 33 studies, most of medium quality. The meta-analysis included 20 of these published studies. The 13 remaining articles did not provide sufficient dichotomous data and were systematically reviewed, revealing results consistent with the meta-analysis. Our results revealed that high BW (>4000 g) was associated with increased risk of obesity (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.91-2.24) compared with subjects with BW ≤ 4000 g. Low BW (<2500 g) was associated with decreased risk of obesity (OR, 0.61; 95% CI, 0.46-0.80) compared with subjects with BW ≥ 2500 g. However, when two studies exhibited selection bias were removed, the results indicated no significant association between low BW and obesity (OR, 0.77; 95% CI, 0.58-1.04). Sensitivity analyses showed that differences in the study design, sample size and quality grade of the study had an effect on the low BW/obesity association, which low BW was not associated with the risk of obesity in cohort studies, studies with large sample sizes and studies with high quality grades. Pooled results were similar when normal birth weight (2500-4000 g) was used as the reference category. Subgroup analyses based on different growth and developmental stages (pre-school children, school children and adolescents) also revealed that high BW was associated with increased risk of obesity from childhood to early adulthood. No significant evidence of publication bias was present. These results suggest that high BW is associated with increased risk of obesity and may serve as a mediator between prenatal influences and later disease risk.

Sporadicity: Between periodic and chaotic dynamical behaviors

We define the class of sporadic dynamical systems as the systems where the algorithmic complexity of Kolmogorov [Kolmogorov, A. N. (1983) Russ. Math. Surv. 38, 29-40] and Chaitin [Chaitin, G. J. (1987) Algorithmic Information Theory (Cambridge Univ. Press, Cambridge, U.K.)] as well as the logarithm of separation of initially nearby trajectories grow as n(v(0) )(log n)(v(1) ) with 0 < v(0) < 1 or v(0) = 1 and v(1) < 0 as time n --> infinity. These systems present a behavior intermediate between the multiperiodic (v(0) = 0, v(1) = 1) and the chaotic ones (v(0) = 1, v(1) = 0). We show that intermittent systems of Manneville [Manneville, P. (1980) J. Phys. (Paris) 41, 1235-1243] as well as some countable Markov chains may be sporadic and, furthermore, that the dynamical fluctuations of these systems may be of Lévy's type rather than Gaussian.

Association of nuclear factor κB expression with a poor outcome in nasopharyngeal carcinoma

The aim of this study was to determine the relationship between nuclear factor κB and the prognosis of patients with nasopharyngeal carcinoma. We used immunohistochemical studies to examine nuclear factor κB expression in 42 patients with nasopharyngeal carcinoma. The results showed that tumors positive for nuclear factor κB were associated with an increased relapse potential, poor disease-free survival, and reduced overall survival in nasopharyngeal carcinoma. Our study indicates that nuclear factor κB could be an independent molecular marker for predicting poor prognosis among patients with nasopharyngeal carcinoma. Understanding the biology of nuclear factor κB-mediated pathways may lead to the development of novel therapeutic strategies for nasopharyngeal carcinoma.

Activation of GABAergic neurons following tooth pulp stimulation

The functional impact of GABA (gamma-aminobutyric acid)ergic neurons in nociceptive transmission of the spinal trigeminal nucleus is not fully established. Using both the glutamic acid decarboxylase (GAD)(67)-green fluorescence protein (GFP) knock-in mouse and the tooth pulp stimulation model, we performed double-immunofluorescent histochemistry to determine the characteristics of GABAergic neuron activation in the spinal trigeminal nucleus. The number of Fos-positive GABAergic neuronal profiles was significantly increased 2 hrs after tooth pulp stimulation. The Fos/GFP double-labeled neurons were mainly present in superficial laminae of the spinal trigeminal subnucleus interpolaris-caudalis transition (Vi/Vc) and subnucleus caudalis (Vc) on the side ipsilateral to the stimulation. Subsequently, the number of double-labeled neurons decreased gradually and became comparable with that of the controls by 48 hrs. Our results provide direct morphological evidence that a subset of GABAergic neurons in the spinal trigeminal system was activated during tooth pulp stimulation.

Telbivudine preserves T-helper 1 cytokine production and downregulates programmed death ligand 1 in a mouse model of viral hepatitis

Telbivudine is an orally bioavailable L-nucleoside with potent and specific anti-hepatitis B virus activity. The higher rate of hepatitis B e antigen (HBeAg) seroconversion during telbivudine treatment than other potent anti-HBV agents suggests a potential immunomodulatory effect. We sought to determine the effects of telbivudine on the immune system, particularly on cytokine production and T-cell response, using an animal model with mouse hepatitis virus strain 3 (MHV-3)-induced hepatitis. The effects of telbivudine on virus replication and cytokine production were investigated in vitro using MHV-3-infected macrophages, and the effects on T-cell response were investigated in vivo in an MHV-3-induced viral hepatitis model. Telbivudine had no effect on MHV-3 replication in macrophages. However, the production of tumour necrosis factor-alpha and interleukin-12 was increased significantly in MHV-3-induced macrophages treated with telbivudine. In vivo survival was enhanced in telbivudine-treated mice, with marked normalization in clinical conditions and histological lesions. Serum levels of interferon-gamma were elevated significantly after telbivudine treatment in MHV-3-infected C3H mice. In contrast, serum interleukin-4 levels were decreased significantly. Furthermore, telbivudine treatment enhanced the ability of T cells to undergo proliferation and secrete cytokines but did not affect cytotoxicity of infected hepatocytes. Of note, we found that telbivudine treatment suppressed programmed death ligand 1 expression on T cells. The results demonstrate the immunomodulatory properties of telbivudine, independent of its antiviral activity, in a mouse model of MHV-3-induced hepatitis.

Environmental temperature has an influence on timing of the first ovulation of seasonal estrus in the mare

A 10-yr retrospective analysis of the time of onset of seasonal ovulation derived from the records of a Thoroughbred horse stud at latitude 35 degrees S revealed a significant variation between years. The onset of seasonal ovulation was closely related to both the maximum (correlation coefficient r=0.56; P=0.09) and minimum (r=-0.67; P<0.01) environmental temperatures. The trend of the temperature rise and the levels attained in the weeks immediately prior to ovulation were similar for both the environmental maximum and minimum temperatures in all years of the study. Environmental temperature may therefore play an important adjuvant zeitgeber for the timing of the first ovulation of estrus in the mare.

Efficiency and spectrum enhancement in a tapered free-electron laser amplifier

We report the first experimental characterization of efficiency and spectrum enhancement in a laser-seeded free-electron laser using a tapered undulator. Output and spectra in the fundamental and third harmonic were measured versus distance for uniform and tapered undulators. With a 4% field taper over 3 m, a 300% (50%) increase in the fundamental (third harmonic) output was observed. A significant improvement in the spectra with the elimination of sidebands was observed using a tapered undulator. The experiment is in good agreement with predictions using the MEDUSA simulation code.

Retinol-binding protein 4 is associated with impaired glucose regulation and microalbuminuria in a Chinese population

AIMS/HYPOTHESIS

Increased retinol-binding protein 4 (RBP4) has been reported in association with insulin resistance and type 2 diabetes. We aimed to investigate the association of serum RBP4 with impaired glucose regulation and microalbuminuria in Chinese adults aged 40 years or older.

METHODS

Serum RBP4 was measured in 763 individuals with normal glucose regulation, 508 with impaired glucose regulation and 524 newly diagnosed diabetic patients. Serum RBP4 was measured using ELISA and urine albumin/creatinine ratio was used to determine the urinary albumin excretion.

RESULTS

Serum RBP4 concentrations were significantly higher in participants with isolated impaired fasting glucose, isolated impaired glucose tolerance, combined impaired fasting glucose/impaired glucose tolerance and diabetes than in those with normal glucose regulation, whereas serum RBP4 levels were not different in the four groups with dysregulation of glucose metabolism. RBP4 was associated with a higher risk for impaired glucose regulation (OR 1.011 for each 1 microg/ml increase in RBP4, 95% CI 1.000-1.022, p = 0.04) after adjustment for sex, age, BMI, current smoking and alcohol intake, family history of diabetes, insulin resistance, triacylglycerol, total cholesterol, and HDL- and LDL-cholesterol; the corresponding OR of combined impaired glucose regulation and type 2 diabetes was 1.022 (95% CI 1.009-1.035, p = 0.0009). RBP4 was associated with the risk of microalbuminuria (OR 1.023, 95% CI 1.004-1.042, p = 0.01) after adjustment for sex, age, smoking habit and alcohol intake, BMI, waist/hip ratio, homeostasis model assessment of insulin resistance, GFR, triacylglycerol, total cholesterol, and HDL- and LDL-cholesterol.

CONCLUSIONS/INTERPRETATION

Serum RBP4 level is closely associated with impaired glucose regulation and is an independent risk factor for microalbuminuria.

Characterization and sources of PAHs in an urban river system in Beijing, China

Water samples from 20 locations on rivers in the Tongzhou District of Beijing were collected four times from July 2005 to March 2006. In addition, sediment samples were collected in July 2005. All samples were analyzed for 16 US Environmental Protection Agency (EPA) priority pollutants polycyclic aromatic hydrocarbons (PAHs). The concentration, distribution, seasonal variation, and sources of the 16 PAH compounds identified in the water samples, suspended particles, and surface sediments were then evaluated. The concentrations of PAHs in the water and suspended particle and surface sediment samples ranged from 87.3 to 1,890 ng l(-1), 1,330 to 27,700 ng g(-1), and 156 to 8,650 ng g(-1), respectively. These results demonstrated that rivers in the Tongzhou District of Beijing had a high level of PAH pollution, especially in the suspended particles. The highest and lowest concentrations of PAHs in the water samples were observed in summer and spring. However, the seasonal variations in the concentration of PAHs in the suspended particles were more complicated. The dominant compounds in the water, suspended particle, and surface sediment samples were two-, three- and four-ring PAH compounds, respectively. Ratio analysis illustrated that fuel-burning was the primary source of PAHs in the study area. Gasoline, diesel, coal, and coke oven sources were identified and the contributions of the different fuel-burning sources were then calculated using factor analysis and multiple linear regression. These analyses revealed that coal combustion, gasoline combustion plus coke oven emission, and diesel combustion accounted for 38.8%, 38.5%, and 22.7% of the PAHs in suspended particles, respectively.

The association between MIF-173 G>C polymorphism and prostate cancer in southern Chinese

BACKGROUND AND OBJECTIVES

Accumulating epidemiological and molecular evidence suggests that inflammation is an important component in the etiology of PCa. Macrophage migration inhibitory factor (MIF) plays an important role in the pro- and anti-inflammatory response to infection. This study is aimed at investigating the potential association between MIF-173 G>C polymorphism, Gleason score, clinical stage, and prostate-specific antigen (PSA) value with respect to PCa incidence among the Han nationality in Southern China.

METHODS

Genotyping was performed by using tetraprimer polymerase chain reaction (PCR) on 259 PCa patients and 301 cancer-free controls.

RESULTS

We found that the MIF-173*C variant allele was significantly associated with an increased risk of PCa [adjusted odd ratio (OR) = 2.99, 95% confident interval (CI): 1.94-4.60] and higher Gleason scores from the PCa subjects (adjusted OR = 10.72, 95% CI: 5.35-21.49). In addition, we noted that the MIF -173*C variant allele was related to higher clinical stages and PSA values in PCa patients (adjusted OR = 15.68, 95% CI: 7.40-33.23; adjusted OR = 4.37, 95% CI: 2.41-7.92, respectively).

CONCLUSION

Our data suggest that MIF-173 polymorphisms may be associated with a higher incidence of prostate cancer compared to controls, and appears to be associated with higher Gleason scores, higher clinical stages, and PSA values in those with prostate cancer.

Visible and near-infrared radiative properties of vertically aligned multi-walled carbon nanotubes

This work investigates the reflection and scattering from vertically aligned carbon nanotubes, fabricated on silicon substrate using thermally enhanced chemical vapor deposition with both tip-growth and base-growth mechanisms. The directional-hemispherical reflectance in the visible and near-infrared wavelengths was measured with an integrating sphere. The polarization-dependent bidirectional reflectance distribution function was characterized with a laser scatterometer at the wavelength of 635 nm. The effective medium theory was used to elucidate the mechanism of high absorptance (greater than 0.97 in the spectral region from 400 to 1800 nm) of the multi-walled carbon nanotube samples. It is observed that scattering by impurities on the top of the nanotubes, by the nanotube tips, and by defects and misalignment can significantly increase the reflectance and introduce retroreflection. This study may facilitate application of carbon nanotubes in pyroelectric detectors as well as thermophotovoltaic emitters and absorbers.

Electron spin control in dilute nitride semiconductors

We report on a study of spin-dependent recombination processes (SDR) for conduction band electrons on deep paramagnetic centers in a series of GaAs(1-y)N(y) epilayers by time-resolved optical orientation experiments. We demonstrate that this dilute nitride compound can be used as an effective electron spin filter under a polarized optical excitation of appropriate intensity. This optimum intensity can moreover be controlled by adjusting the nitrogen composition in the layer.

Active control and spatial mapping of mid-infrared propagating surface plasmons

Periodic arrays of subwavelength apertures in metal films have been shown to exhibit strongly enhanced transmission at wavelengths determined by the periodicity of the film as well as the optical properties of the metal and surrounding dielectric material. Here we investigate the coupling between such a grating and a Quantum Cascade Laser. By actively tuning the optical properties of our grating, we control the coupling of laser light to the plasmonic structure, switching our grating from a predominantly transmitting state to a state that allows coupling to propagating surface waves, which can then be imaged on the metallic surface.

Room-temperature defect-engineered spin filter based on a non-magnetic semiconductor

Generating, manipulating and detecting electron spin polarization and coherence at room temperature is at the heart of future spintronics and spin-based quantum information technology. Spin filtering, which is a key issue for spintronic applications, has been demonstrated by using ferromagnetic metals, diluted magnetic semiconductors, quantum point contacts, quantum dots, carbon nanotubes, multiferroics and so on. This filtering effect was so far restricted to a limited efficiency and primarily at low temperatures or under a magnetic field. Here, we provide direct and unambiguous experimental proof that an electron-spin-polarized defect, such as a Ga(i) self-interstitial in dilute nitride GaNAs, can effectively deplete conduction electrons with an opposite spin orientation and can thus turn the non-magnetic semiconductor into an efficient spin filter operating at room temperature and zero magnetic field. This work shows the potential of such defect-engineered, switchable spin filters as an attractive alternative to generate, amplify and detect electron spin polarization at room temperature without a magnetic material or external magnetic fields.

A Kunjin replicon vector encoding granulocyte macrophage colony-stimulating factor for intra-tumoral gene therapy

We have recently developed a non-cytopathic RNA replicon-based viral vector system based on the flavivirus Kunjin. Here, we illustrate the utility of the Kunjin replicon system for gene therapy. Intra-tumoral injections of Kunjin replicon virus-like particles encoding granulocyte colony-stimulating factor were able to cure >50% of established subcutaneous CT26 colon carcinoma and B16-OVA melanomas. Regression of CT26 tumours correlated with the induction of anti-cancer CD8 T cells, and treatment of subcutaneous CT26 tumours also resulted in the regression of CT26 lung metastases. Only a few immune-based strategies are able to cure these aggressive tumours once they are of a reasonable size, illustrating the potential of this vector system for intra-tumoral gene therapy applications.

Temporal and spatial expression of TGF-beta2 in tooth crown development in mouse first lower molar

Transforming Growth Factor beta2 (TGF-beta2) is involved in the regulation of many important cellular processes during tooth development. In this study we systematically characterized the expression pattern of TGF-beta2 in vivo and further analyzed its possible roles during different developmental stages of mouse first lower molar using immunofluorescence histochemical method with confocal microscopy. TGF-beta2 signaling was detected in different developing stages in both dental epithelium and surrounding dental mesenchyme. For the first time, we found that the basement membrane and epithelial cells in the basal layer showed no immunostaining from embryonic day 11 to 13; the primary enamel knot and secondary enamel knot exhibited pronounced immunostaining with different expression patterns at embryonic day 14 and 16. In addition, the mature ameloblast lost immunoreactivity, but the secretory ameloblast still exhibited positive immunoreaction at day 2 of postnatal development. Collectively, the temporospatial distribution patterns of TGF- beta2, especially in the basement membrane, epithelial cells in the basal layer, enamel knot, mature odontoblast and ameloblast, suggested a close association between TGF-beta2 signaling and tooth crown development, and indicated that TGF-beta2 might participate in tooth initiation, epithelial morphogenesis, formation of dentine matrix, and ameloblast differentiation.

In vitro bioactivity evaluation of titanium and niobium metals with different surface morphologies

Current orthopaedic biomaterials research mainly focuses on designing implants that could induce controlled, guided and rapid healing. In the present study, the surface morphologies of titanium (Ti) and niobium (Nb) metals were tailored to form nanoporous, nanoplate and nanofibre-like structures through adjustment of the temperature in the alkali-heat treatment. The in vitro bioactivity of these structures was then evaluated by soaking the treated samples in simulated body fluid (SBF). It was found that the morphology of the modified surface significantly influenced the apatite-inducing ability. The Ti surface with a nanofibre-like structure showed better apatite-inducing ability than the nanoporous or nanoplate surface structures. A thick dense apatite layer formed on the Ti surface with nanofibre-like structure after 1 week of soaking in SBF. It is expected that the nanofibre-like surface could achieve good apatite formation in vivo and subsequently enhance osteoblast cell adhesion and bone formation.

Biological aerated filter treated textile washing wastewater for reuse after ozonation pre-treatment

The combination of chemical and biological treatment processes is a promising technique to reduce refractory organics from wastewater. Ozonation can achieve high color removal, enhance biodegradability, and reduce the chemical oxygen demand (COD). The biological technique can further decrease COD of wastewater after ozonation as a pre-treatment. In this study the ozonizing-biological aerated filter processes were used to treat textile washing wastewater for reuse after conventional treatment. The result showed that when the influent qualities were COD about 80 mg/L, color 16 degree and turbidity about 8 NTU, using the combination processes with the dosages of ozone at 30-45 mg/L with the hydraulic retention time (HRT) of biological aerated filter (BAF) at 3-4 hours respectively, gave effluent qualities of COD less than 30 mg/L, color 2 degree and turbidity less than 1NTU. The cost of treatment was less than one yuan/t wastewater, and these processes could enable high quality washing water reuse in textile industry.