Two-color deep-ultraviolet 40-fs pulses based on parametric amplification at 100 kHz

We present a 100-kHz deep-ultraviolet (DUV) laser system that generates 40-fs pulses. A 520-nm pulse generated by a noncollinear optical parametric amplifier pumped by the second harmonic of a Ti:sapphire laser is converted into 226- and 260-nm DUV pulses simultaneously with pulse energies of 250 and 130 nJ (average powers: 25 and 13 mW), respectively. The DUV pulses were estimated to have durations of ca. 40 fs by cross-correlation measurements based on (1 + 1') two-color ionization of gaseous nitric oxide.

Formation of hydroxyl radical from San Joaquin Valley particles extracted in a cell-free surrogate lung fluid

Previous studies have suggested that the adverse health effects from ambient particulate matter (PM) are linked to the formation of reactive oxygen species (ROS) by PM in cardiopulmonary tissues. While hydroxyl radical ((•)OH) is the most reactive of the ROS species, there are few quantitative studies of (•)OH generation from PM. Here we report on (•)OH formation from PM collected at an urban (Fresno) and rural (Westside) site in the San Joaquin Valley (SJV) of California. We quantified (•)OH in PM extracts using a cell-free, phosphate-buffered saline (PBS) solution with or without 50μM ascorbate (Asc). The results show that generally the urban Fresno PM generates much more (•)OH than the rural Westside PM. The presence of Asc at a physiologically relevant concentration in the extraction solution greatly enhances (•)OH formation from all the samples. Fine PM (PM(2.5)) generally makes more (•)OH than the corresponding coarse PM (PM(cf), i.e. with diameters of 2.5 to 10 μm) normalized by air volume collected, while the coarse PM typically generates more (•)OH normalized by PM mass. (•)OH production by SJV PM is reduced on average by (97±6)% when the transition metal chelator desferoxamine (DSF) is added to the extraction solution, indicating a dominant role of transition metals. By measuring calibration curves of (•)OH generation from copper and iron, and quantifying copper and iron concentrations in our particle extracts, we find that PBS-soluble copper is primarily responsible for (•)OH production by the SJV PM, while iron often makes a significant contribution. Extrapolating our results to expected burdens of PM-derived (•)OH in human lung lining fluid suggests that typical daily PM exposures in the San Joaquin Valley are unlikely to result in a high amount of pulmonary (•)OH, although high PM events could produce much higher levels of (•)OH, which might lead to cytotoxicity.

Paraoxonase 1 (PON1) gene variants are not associated with clopidogrel response

A common functional variant in paraoxonase 1 (PON1), Q192R, was recently reported to be a major determinant of clopidogrel response. This variant was genotyped in 566 participants of the Amish Pharmacogenomics of Anti-Platelet Intervention (PAPI) study and in 227 percutaneous coronary intervention (PCI) patients. Serum paraoxonase activity was measured in a subset of 79 PAPI participants. PON1 Q192R was not associated with pre- or post-clopidogrel platelet aggregation in the PAPI study (P = 0.16 and P = 0.21, respectively) or the PCI cohort (P = 0.47 and P = 0.91, respectively). The Q192 allele was not associated with cardiovascular events (hazard ratio (HR) 0.46, 95% confidence interval (CI) 0.20-1.06; P = 0.07). No correlation was observed between paraoxonase activity and post-clopidogrel platelet aggregation (r(2) < 0.01, P = 0.78). None of 49 additional PON1 variants evaluated was associated with post-clopidogrel platelet aggregation. These findings do not support a role for PON1 as a determinant of clopidogrel response.

The relationship between MHC-DRB1 gene second exon polymorphism and hydatidosis resistance of Chinese Merino (Sinkiang Junken type), Kazakh and Duolang sheep

The present study aimed at detecting the association of ovine major histocompatibility complex class II (Ovar II) DRB1 gene second exon and susceptibility or resistance to hydatidosis in three sheep breeds of Sinkiang. The MHC-DRB1 second exon was amplified by polymerase chain reaction (PCR) from DNA samples of healthy sheep and sheep with hydatidosis. PCR products were characterized by the restriction fragment length polymorphism (RFLP) technique. Five restriction enzymes, Mval, Haelll, Sacl, Sacll, Hin1l, were used, yielding 14 alleles and 31 restriction patterns. Frequencies of patterns Mvalbc, Hin1lab, Sacllab, Haelllde, Haellldf, Haellldd (P < 0.01) in Kazakh sheep, Saclab (P < 0.05) in Duolang sheep, and Haelllab, Haelllce, Haelllde, Haelllee (P < 0.01) in Chinese Merino (Sinkiang Junken type) sheep, were significantly higher in healthy sheep compared with infected sheep. These results indicated a strong association between these patterns and hydatidosis resistance. In contrast, the frequencies of Mvalbb, Saclaa, Hinl lbb, Haelllef (P < 0.01) and Haelllab (P < 0.05) in Kazakh sheep, Saclbb, Haelllae, Hin1lab (P < 0.05), Haelllaa, Haelllbe, Haelllef (P < 0.01) in Duolang sheep, Sacllaa (P < 0.05) and Haelllbd, Hin1lbb, Haelllcf, Haelllef (P < 0.01) in Chinese Merino sheep (Sinkiang Junken type) were significantly lower in healthy sheep compared with infected sheep. This indicated a strong association between these patterns and hydatidosis susceptibility. In addition, sheep with the pattern of Haelllef demonstrated a high hydatidosis susceptibility (P < 0.01) in all three breeds, while sheep with the pattern Haelllde demonstrated significant hydatidosis resistance (P < 0.01) in Kazakh and Chinese Merino sheep (Sinkiang Junken type). These results suggest that the Ovar-DRB1 gene plays a role in resistance to hydatidosis infection in the three sheep breeds.

Enhanced neurodegeneration after a high dose of methamphetamine in adenosine A3 receptor null mutant mice

Previous reports have indicated that adenosine A3 receptor (A3R) knockout mice are more sensitive to ischemic or hypoxic brain injury. The purpose of this study was to examine if suppression of A3R expression is associated with increase in sensitivity to injury induced by a high dose of methamphetamine (Meth). Adult male A3R null mutant (-/-) mice and their controls (+/+) were injected with four doses (2 h apart) of Meth (10 mg/kg) or saline. Animals were placed in a behavioral activity chamber, equipped with food and water, for 52 h starting from one day after injections. The first 4 h were used for studying exploratory behaviors, and the next 48 h were used to measure locomotor activity. High doses of Meth equally reduced the 4-h exploratory behavior in -/- and +/+ mice. Meth suppressed locomotor activity between 4 and 52 h in both groups, with a greater reduction being found in the -/- mice. Brain tissues were collected at 3 days after the Meth or saline injections. Meth treatment reduced striatal dopamine (DA) levels in both +/+ and -/- mice with an increase in 3,4-dihydroxyphenylacetic acid (DOPAC)/DA ratio being found only in -/- animals. Meth also significantly increased ionized calcium-binding adaptor molecule 1 (Iba-1) and cleaved caspase-3 level in striatum, as well as Iba-1 and TNFα mRNA expression in nigra in -/-, compared to +/+, mice. Previous studies have shown that pharmacological suppression of vesicular monoamine transport 2 (VMAT2) by reserpine enhanced Meth toxicity by increasing cytosolic DA and inflammation. A significant reduction in striatal VMAT2 expression was found in -/- mice compared to +/+ mice, suggesting that increase in sensitivity to Meth injury in -/- mice may be related to a reduction in VMAT2 expression in these mice. In conclusion, our data suggest that A3R -/- mice are more sensitive to high doses of Meth.

Biochemical markers comparison of dynamic hip screw and Gamma nail implants in the treatment of stable intertrochanteric fracture: a prospective study of 60 patients

This prospective study compared the extent of surgical trauma following dynamic hip screw (DHS) or Gamma nail (GN) implantation in 60 patients (≥ 60 years old) with stable intertrochanteric fracture. Levels of the biochemical markers creatinine kinase (CK) and C-reactive protein (CRP) were measured pre- and postoperatively. CRP levels were statistically significantly lower on postoperative days 1 and 2 in patients in the DHS versus the GN group; no other differences were observed. Surgical procedures for DHS implantation were considered less invasive than those for GN implantation, although the degree of muscle damage was similar in both groups. The degree of bone and bone marrow damage, rather than muscle tissue damage, may be crucial for determining the CRP response during the operative period. It is concluded that DHS implantation may be described as a more 'systemically' minimally invasive procedure than GN implantation.

Rhenium-188 labeled recombinant human plasminogen kringle5 (rhk5) and preliminary biodistribution. Evaluation in mice bearing A549 tumours

AIM

Angiogenesis plays a critical role in tumour formation and metastasis. Suitable radiolabeled angiogenesis inhibitor can be used for noninvasive imaging of angiogenesis and radionuclide therapy. Here we prepare rhenium-188 labeled recombinant human plasminogen kringle5 (188Re-rhk5) in a convenient manner than evaluate its properties in A549 lung adenocarcinoma.

METHODS

188Re-rhk5 was obtained by conjugating His group at the C end of rhk5 with fac-[188Re(H2O)3(CO)3]+. Chelating efficiency of fac-[188Re(H2O)3(CO)3]+ and radiolabeling efficiency of 188Re-rhk5 were measured by radio thin-layer chromatography (RTLC). In vitro stability of 188Re-rhk5 was determined in human serum at 37°C and analyzed by RTLC. Competition test was also performed to verify the specificity of binding. A biodistribution study was carried out in nude mice bearing A549 lung adenocarcinoma.

RESULTS

188Re-rhk5 was obtained with a radiolabel efficiency of 66.1%, the radiochemical purity (RCP) can reach 95.2% after purification. 188Re-rhk5 showed high stability in human serum, the RCP was more than 80% even 12 h after incubation. Competition test showed a high binding specificity. Furthermore, this radio-complex was excreted mainly through kidneys and showed specific tumour uptake in mice bearing A549 tumours.

CONCLUSION

188Re-rhk5 was prepared by a simple method. Preliminary biodistribution results showed its potential as an agent for possible tumour imaging, therapy and encouraged further investigation.

Vitamin E and selenium levels are within normal range in pigs diagnosed with mulberry heart disease and evidence for viral involvement in the syndrome is lacking

Mulberry heart disease (MHD) in pigs is characterized by lesions of acute haemorrhagic myocarditis and myocardial necrosis. The objectives of this study were to determine the levels of vitamin E and selenium and 13 other trace minerals in heart and liver tissues and to determine the prevalence of certain viral infections in heart tissues from MHD-affected and MHD-unaffected pigs and the vitamin E and selenium concentration in feed samples from selected farms with MHD. Based on the pathological examination, 114 pigs were separated into MHD lesion-negative (L-NEG) (n = 57) and MHD lesion-positive (L-POS) (n = 57) groups. Seventy-three samples (40 L-NEG and 33 L-POS) were subjected to chemical analysis, and 66 (32 L-NEG and 34 L-POS) were subjected to PCR detection for viral pathogens. Lower (P < 0.05) levels of myocardial copper, lower (P < 0.05) levels of hepatic magnesium and higher (P < 0.05) levels of myocardial and hepatic sodium were detected in the L-POS cases. Although lower (P < 0.05) levels of hepatic selenium were detected in L-POS group, all were within the normal range. Analysis of feed samples (n = 22) revealed that selenium levels in all the samples were above the legal limit (0.3 ppm) for pigs. Vitamin E levels in all feed samples were above 20 IU/kg. Among the 66 pigs subjected to PCR detection, there were 19, 4, 13, 8, 2 and 1 animals positive for porcine circovirus type 2, porcine reproductive and respiratory syndrome virus, pan-herpes virus, porcine enterovirus, pan-pestivirus and porcine parvovirus, respectively. Clear evidence of viral association with L-POS was lacking.

Derivation and characterization of Chinese human embryonic stem cell line with high potential to differentiate into pancreatic and hepatic cells

BACKGROUND

Human embryonic stem cells have prospective uses in regenerative medicine and drug screening. Every human embryonic stem cell line has its own genetic background, which determines its specific ability for differentiation as well as susceptibility to drugs. It is necessary to compile many human embryonic stem cell lines with various backgrounds for future clinical use, especially in China due to its large population. This study contributes to isolating new Chinese human embryonic stem cell lines with clarified directly differentiation ability.

METHODS

Donated embryos that exceeded clinical use in our in vitro fertilization-embryo transfer (IVF-ET) center were collected to establish human embryonic stem cells lines with informed consent. The classic growth factors of basic fibroblast growth factor (bFGF) and recombinant human leukaemia inhibitory factor (hLIF) for culturing embryonic stem cells were used to capture the stem cells from the plated embryos. Mechanical and enzymetic methods were used to propagate the newly established human embryonic stem cells line. The new cell line was checked for pluripotent characteristics with detecting the expression of stemness genes and observing spontaneous differentiation both in vitro and in vivo. Finally similar step-wise protocols from definitive endoderm to target specific cells were used to check the cell line's ability to directly differentiate into pancreatic and hepatic cells.

RESULTS

We generated a new Chinese human embryonic stem cells line, CH1. This cell line showed the same characteristics as other reported Chinese human embryonic stem cells lines: normal morphology, karyotype and pluripotency in vitro and in vivo. The CH1 cells could be directly differentiated towards pancreatic and hepatic cells with equal efficiency compared to the H1 cell line.

CONCLUSIONS

This newly established Chinese cell line, CH1, which is pluripotent and has high potential to differentiate into pancreatic and hepatic cells, will provide a useful tool for embryo development research, along with clinical treatments for diabetes and some hepatic diseases.

Quantum Confinement Effects on the Dielectric Constant of Porous Silicon

The reduction of the dielectric constant due to quantum confinement is studied both experimentally and theoretically. Angle resolved ellipsometry measurements with Ar- and He-Ne-lasers give values for the index of refraction far below what can be accounted for from porosity alone. A modified Penn model to include quantum size effects has been used to calculate the reduction in the static dielectric constant (ε) with extreme confinement. Since the binding energy of shallow impurities depends inversely on ε2, the drastic decrease in the carrier concentration as a result of the decrease in ε leads to a self-limiting process for the electrochemical etching of porous silicon.

Photoluminescence and Sims Studies of Hydrogen Passivation of Mg-Doped P-Type Gallium Nitride

The effects of hydrogen passivation in MOCVD grown Mg doped p-type GaN were studied using low temperature (5K) photoluminescence (PL) and secondary-ion-mass spectroscopy (SIMS). GaN films with different Mg doping level were annealed at 700° C in N2 ambient with different annealing times. The SIMS results indicate that the hydrogen concentration increases with increasing Mg doping level in the as-grown Mg:GaN film. After 20 minutes of annealing, most of the hydrogen escapes from the film. The 3.455 eV PL peak before annealing and the 3.446 eV peak after annealing found in the Mg doped samples were attributed to the exciton bound to the Mg-H complex and to the Mg acceptor, respectively. The shift of the bound exciton peak to higher energy (3.465 eV) in the lightly doped sample is due to an effective n-type compensation associated with an annealing-induced increase in the nitrogen vacancies. In heavily doped Mg:GaN, the decreases in the integrated PL intensity after 700° C annealing may be associated with the hydrogen depassivation of nonradiative recombination centers in the film. The increase of PL intensity in the lightly doped sample after annealing is attributed to the reduction of defects by the annealing process.

Raman and Optical Characterization of Porous Silicon

Raman spectra from electrochemically etched porous silicon are correlated with photoluminescence (PL) data from the same spots of the sample. This correlation is consistent with optical properties of quantum confinement. The dielectric constant determined from angle resolved ellipsometry gives values far below that of bulk silicon. This reduction is due to the combined effects of voids as well as quantum confinement. The PL spectrum shows a weak high energy peak around 2.8eV in addition to the strong broad peak at 1.5 to 1.9eV. The temperature dependence of PL resembles that of bound excitons such as Si:S, having a thermal dissociation energy of 100 meV near room temperature. The radiation life time changes from tens of microseconds near room temperature to a few milliseconds at liquid helium temperatures. The rapid increase in lifetime and decrease in PL intensity at low temperatures indicates that phonons are probably involved.

Electrical and Microwave Properties of Mn Implanted (Ba,Sr)TiO3 Thin Films

We have used ion implantation to dope polycrystalline BaxSr(1−x)TiO3 (BST) thin films with Mn. Dopant concentrations were varied in the range of 0.1 at % to 2 at % Mn. X-ray diffraction and TEM studies show that the implantation process significantly damages the film leaving only short range order, but subsequent rapid thermal annealing heals the damage. The effect of the different Mn dopant concentrations on the electrical properties of the complex capacitance, relaxation currents, leakage, C-V, and resistance degradation was investigated. Our initial results show that the implanted films have significantly lower leakage (up to a factor of 10 lower) than the as deposited films for small (<0.5 at % Mn) implantation doses. The capacitance decreased with increasing Mn concentration while the relaxation currents and loss tangents increased.

Microstructure Control of (Ba, Sr)TiO3 Films for Gigabit Dram

(Ba, Sr)TiO3 films were deposited on Pt-coated SiO2/Si wafers by the MOCVD method. Experiments were conducted to investigate the mechanisms of nucleation and growth. It was observed that the diameter of the (Ba, Sr)TiO3 grains is established in the early stages of nucleation and does not increase substantially during the growth of the film. By controlling the process conditions, it is possible to control the final microstructure and improve the electrical properties of (Ba, Sr)TiO3 films. I-V and C-V measurements show that (Ba, Sr)TiO3 films with a thickness of approximately 15nm can produce a charge storage density of >120 fF/μm2 with a leakage current density of < 10 nA/cm2 at IV, making them suitable for Gigabit-scale DRAM applications.

The CKLF1-C19 peptide attenuates allergic lung inflammation by inhibiting CCR3- and CCR4-mediated chemotaxis in a mouse model of asthma

BACKGROUND

  Human chemokine-like factor 1 (CKLF1) is a functional ligand for human CCR4, which is highly expressed on Th2 lymphocytes and plays an important role in the pathogenesis of asthma. The expression and function of CKLF1 are associated with asthma. The CKLF1 C-terminal peptides C19 and C27 also interact with human CCR4. Albeit with weaker chemotactic activity, C19 can inhibit chemotaxis induced by both CKLF1 and CCL17. Here, we explore whether C19 can act as an antagonist in the development of asthma.

METHODS

  A mouse model of asthma and in vitro and in vivo chemotaxis assays were used.

RESULTS

  Using a mouse model of asthma, we demonstrate here that C19 reduces airway eosinophilia, lung inflammation and airway hyperresponsiveness; in contrast, C27 has little effect on these parameters. The inhibitory effects of C19 on CCR4-mediated chemotaxis could be observed in human Th2 lymphocytes and in the splenocytes from ovalbumin-sensitized mice. Furthermore, we show that C19 can inhibit CCL11-induced chemotaxis of mouse eosinophils and human CCR3-transfected or mouse Ccr3-transfected HEK293 cells. In vivo chemotaxis assays revealed that C19 and C27 can reduce CCL11-mediated recruitment of eosinophils into the peritoneal cavity and that this inhibitory effect is stronger for C19 than for C27.

CONCLUSIONS

  Thus, C19 can attenuate airway eosinophilia and lung inflammation by inhibiting CCR3- and CCR4-mediated chemotaxis in a mouse model of asthma. Given its ability to inhibit human CCR3- and CCR4-meditated chemotaxis, C19 has great therapeutic potential for use in the treatment and control of allergic asthma.

Interleukin-17 and interleukin-23 in patients with polymyositis and dermatomyositis

OBJECTIVE

To analyse the concentration of interleukin (IL)-17 and IL-23 in serum and ex vivo culture supernatant of peripheral blood mononuclear cells (PBMCs) from patients with polymyositis (PM) and dermatomyositis (DM) compared with healthy controls (HC).

METHODS

Enzyme-linked immunosorbent assay (ELISA) was used to analyse the concentration of IL-17 and IL-23 from 25 patients with PM, 21 patients with DM, and 12 HC in serum or ex vivo culture supernatant of PBMCs following stimulation ex vivo with anti-CD3/CD28 for 72 h.

RESULTS

The levels of IL-23 increased in the serum and culture supernatant of patients with PM and patients with DM compared with HC. By contrast, concentrations of IL-17 in supernatants from patients with PM and DM were not significantly higher than those from HC. We subdivided the group of DM and PM patients into those with early disease versus those with established disease and found that the levels of IL-17 and IL-23 were much higher in early stage compared to established disease.

CONCLUSION

We have demonstrated that stimulated PBMCs from DM and PM patients produce increased levels of IL-23 as compared to HC. IL-17 and IL-23 levels are increased in early as compared to established disease. This provides further evidence that IL-17/IL-23 may play a crucial role in autoimmune diseases.

Neuroprotection by donepezil against glutamate excitotoxicity involves stimulation of alpha7 nicotinic receptors and internalization of NMDA receptors

BACKGROUND AND PURPOSE

Glutamate excitotoxicity may be involved in ischaemic injury to the CNS and some neurodegenerative diseases, such as Alzheimer's disease. Donepezil, an acetylcholinesterase (AChE) inhibitor, exerts neuroprotective effects. Here we demonstrated a novel mechanism underlying the neuroprotection induced by donepezil.

EXPERIMENTAL APPROACH

Cell damage in primary rat neuron cultures was quantified by lactate dehydrogenase release. Morphological changes associated with neuroprotective effects of nicotine and AChE inhibitors were assessed by immunostaining. Cell surface levels of the glutamate receptor sub-units, NR1 and NR2A, were analyzed using biotinylation. Immunoblot was used to measure protein levels of cleaved caspase-3, total NR1, total NR2A and phosphorylated NR1. Immunoprecipitation was used to measure association of NR1 with the post-synaptic protein, PSD-95. Intracellular Ca(2+) concentrations were measured with fura 2-acetoxymethylester. Caspase 3-like activity was measured using enzyme substrate, 7-amino-4-methylcoumarin (AMC)-DEVD.

KEY RESULTS

Levels of NR1, a core subunit of the NMDA receptor, on the cell surface were significantly reduced by donepezil. In addition, glutamate-mediated Ca(2+) entry was significantly attenuated by donepezil. Methyllycaconitine, an inhibitor of alpha7 nicotinic acetylcholine receptors (nAChR), inhibited the donepezil-induced attenuation of glutamate-mediated Ca(2+) entry. LY294002, a phosphatidyl inositol 3-kinase (PI3K) inhibitor, had no effect on attenuation of glutamate-mediated Ca(2+) entry induced by donepezil.

CONCLUSIONS AND IMPLICATIONS

Decreased glutamate toxicity through down-regulation of NMDA receptors, following stimulation of alpha7 nAChRs, could be another mechanism underlying neuroprotection by donepezil, in addition to up-regulating the PI3K-Akt cascade or defensive system.

Characterization of stem cells from alveolar periodontal ligament

Complete and predicable regeneration of complex periodontal structures, which include cementum, periodontal ligament (PDL), and alveolar bone, has been a great challenge for periodontal researchers. It is generally believed that human PDL from the root surface contains stem cells (r-PDLSCs), which can enhance cementum/PDL-like tissues regeneration in vivo. In this work, PDL was found to possess asymmetrically distributed stem cells observed by long-term bromodeoxyuridine (BrdU) labeling. Putative stem cells from human PDL on the alveolar bone surface (a-PDLSCs) were then isolated and characterized. It was shown that a-PDLSCs exhibited strong proliferation capability and expressed high percentages of mesenchymal stem cell markers. Comparatively, a-PDLSCs had higher multilineage differentiation potential than r-PDLSCs with regard to both osteogenic and adipogenic differentiation. Alkaline phosphatase activity and the expression of mineralization-related markers of a-PDLSCs were also higher than those of r-PDLSCs. In vivo, a-PDLSCs could regenerate bone/PDL-like structures and repair critical-size defects created in calvarial bone of NOD/SCID mice. Autologous PDLSC-mediated periodontal regeneration showed that a-PDLSCs could accomplish reconstruction of alveolar bone more perfectly than r-PDLSCs. Our data suggest that PDLSCs may have quite different characteristics depending on locations. a-PDLSCs may take a synergistic effect with r-PDLSCs in periodontal regeneration.