Licochalcone A Derivatives as Selective Dipeptidyl Peptidase 4 Inhibitors with Anti-Inflammatory Effects.

A set of 22 analogs of licochalcone A was designed and synthesized to explore their potentials as dipeptidyl peptidase 4 (DPP4) inhibitors with anti-inflammatory effects. The anti-DPP4 effects of these analogs were evaluated using the fluorescent substrate Gly-Pro-N-butyl-4-amino-1,8-naphthalimide (GP-BAN). The nitro-substituted analogue 27 exhibited the most potent activity (Ki = 0.96 µM). A structure-activity relationship investigation revealed that 4-hydroxyl and 5-chloro substituents are essential for DPP4 inhibition, while the 3'-nitro substituent improved both DPP4 inhibition and microsomal stability. Furthermore, compound 27 demonstrated good selectivity for DPP4 over other proteases, including dipeptidyl peptidase 9 (DPP9), thrombin, prolyl endopeptidase (PREP), and fibroblast activation protein (FAP). The cytotoxic effect of 27 was evaluated in cancer cell lines HepG-2 and Caco-2 and in somatic RAW264.7 cells and RPTECs. Compound 27 showed no toxicity to normal cells and weak toxicity to cancer cells. In a living cell imaging assay, 27 blocked the dipeptidase activity of DPP4 in both Caco-2 and HepG-2 cells. This compound also dose-dependently suppressed the expression levels of the chemokines tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß).

Discovery of 4'-trifluoromethylchalcones as novel, potent and selective hCYP1B1 inhibitors without concomitant AhR activation.

Human cytochrome P450 1B1 (hCYP1B1), an extrahepatic cytochrome P450 enzyme over-expressed in various tumors, has been validated as a promising target for preventing and treating cancers. Herein, two series of chalcone derivatives were synthesized to discover potent hCYP1B1 inhibitors without AhR agonist effect. Structure-activity relationship (SAR) studies demonstrated that 4'-trifluoromethyl on the B-ring strongly enhanced the anti-hCYP1B1 effects, identifying A9 as a promising lead compound. Further SAR analysis on A9 derivatives (modified A-ring of 4'-trifluoromethylchalcone) showed that introducing 2-methoxyl improved the anti-hCYP1B1 effect and selectivity, while introducing a methoxyl at the C-4 site was beneficial for avoiding AhR activation. Ultimately, five 4'-trifluoromethyl chalcones were identified as potent hCYP1B1 inhibitors (IC50 < 10 nM), while B18 exhibits the most potent anti-hCYP1B1 effect (IC50 = 3.6 nM), suitable metabolic stability and good cell-permeability. B18 also acted as an AhR antagonist and could down-regulate hCYP1B1 in living systems. Mechanistic studies showed that B18 potently inhibited hCYP1B1 in a competitive inhibition manner (Ki = 3.92 nM), while docking simulations revealed that B18 could tightly bind to the catalytic cavity of hCYP1B1 mainly via hydrophobic and hydrogen-bonding interactions. Furthermore, B18 could potently inhibit hCYP1B1 in living cells and showed remarkable anti-migration ability on MFC-7 cells. Taken together, this study deciphered the SARs of chalcones as hCYP1B1 inhibitors and provided several potent hCYP1B1 inhibitors as promising candidates for the development of more efficacious anti-migration agents.

Discovery and Characterization of the Biflavones From Ginkgo biloba as Highly Specific and Potent Inhibitors Against Human Carboxylesterase 2.

Human carboxylesterase 2 (CES2), one of the most abundant hydrolases distributed in the small intestine, has been validated as a key therapeutic target to ameliorate the intestinal toxicity caused by irinotecan. This study aims to discover efficacious CES2 inhibitors from natural products and to characterize the inhibition potentials and inhibitory mechanisms of the newly identified CES2 inhibitors. Following high-throughput screening and evaluation of the inhibition potency of more than 100 natural products against CES2, it was found that the biflavones isolated from Ginkgo biloba displayed extremely potent CES2 inhibition activities and high specificity over CES1 (>1000-fold). Further investigation showed that ginkgetin, bilobetin, sciadopitysin and isoginkgetin potently inhibited CES2-catalyzed hydrolysis of various substrates, including the CES2 substrate-drug irinotecan. Notably, the inhibition potentials of four biflavones against CES2 were more potent than that of loperamide, a marketed anti-diarrhea agent used for alleviating irinotecan-induced intestinal toxicity. Inhibition kinetic analyses demonstrated that ginkgetin, bilobetin, sciadopitysin and isoginkgetin potently inhibited CES2-catalyzed fluorescein diacetate hydrolysis via a reversible and mixed inhibition manner, with K i values of less than 100 nM. Ensemble docking and molecular dynamics revealed that these biflavones could tightly and stably bind on the catalytic cavity of CES2 via hydrogen bonding and π-π stacking interactions, while the interactions with CES1 were awfully poor. Collectively, this study reports that the biflavones isolated from Ginkgo biloba are potent and highly specific CES2 inhibitors, which offers several promising lead compounds for developing novel anti-diarrhea agent to alleviate irinotecan-induced diarrhea.

Design, synthesis and biological evaluation of indanone-chalcone hybrids as potent and selective hCES2A inhibitors.

Human carboxylesterase 2 (hCES2A), one of the major serine hydrolases distributed in the small intestine, plays a crucial role in hydrolysis of ester-bearing drugs. Accumulating evidence has indicated that hCES2A inhibitor therapy can modulate the pharmacokinetic and toxicological profiles of some important hCES2A-substrate drugs, such as the anticancer agent CPT-11. Herein, a series of indanone-chalcone hybrids are designed and synthesized to find potent and highly selective hCES2A inhibitors. Inhibition assays demonstrated that most indanone-chalcone hybrids displayed strong to moderate hCES2A inhibition activities. Structure-hCES2A inhibition activity relationship studies showed that introduction of a hydroxyl at the C4' site and introduction of an N-alkyl group at the C6 site were beneficial for hCES2A inhibition. Particularly, B7 (an N-alkylated 1-indanone-chalcone hybrid) exhibited the most potent inhibition on hCES2A and excellent specificity (this agent could not inhibit other human esterases including hCES1A and butyrylcholinesterase). Inhibition kinetic analyses demonstrated that B7 potently inhibited hCES2A-mediated FD hydrolysis in a mixed inhibition manner, with a calculated Ki value of 0.068 µM. Furthermore, B7 was capable of inhibiting intracellular hCES2A in living cells and displayed good metabolic stability. Collectively, our findings show that indanone-chalcone hybrids are good choices for the development of hCES2A inhibitors, while B7 is a promising candidate for the development of novel anti-diarrhea agents to ameliorate irinotecan-induced intestinal toxicity.

Exploratory meta-analysis on dose-related efficacy and complications of rhBMP-2 in anterior cervical discectomy and fusion: 1,539,021 cases from 2003 to 2017 studies.

BACKGROUND/OBJECTIVE: Anterior cervical discectomy and fusion (ACDF), commonly using autogenous iliac bone graft may be limited by donor site availability, donor-site morbidity, lower fusion rate among specific patients and longer surgical time. Surgeons used rhBMP-2 as an alternative in order to fill these clinical needs. However, studies comparing with and without rhBMP-2 in ACDF have reported conflicting results on efficacy and complications. Therefore, the purpose of this article was to evaluate efficacy and complications through dose-related rhBMP-2 and surgical level-dependence in ACDF. METHODS: We comprehensively searched PubMed and the Cochrane Library and performed a systematic review and cumulative meta-analysis of all randomized controlled trials (RCTs), prospective and retrospective comparative studies assessing with and without rhBMP-2 treatments. RESULTS: 1 RCTs, 4 prospective studies and 24 retrospective studies including a total of 1,539,021 cases were identified. Patients in ACDF with rhBMP-2 might benefit from significantly higher fusion rates than that in non-rhBMP-2, not only total value but also in 3 tiers of rhBMP-2 doses. It is worth noting that the low dose of rhBMP-2 (<0.7 mg/level) showed highest fusion rate among all rhBMP-2 doses. Patients in rhBMP-2 also experienced higher complication rate, dysphagia and wound infections than that in non-rhBMP-2. In 2-level ACDF, the fusion rate was significantly better in rhBMP-2 than non-rhBMP-2 but not for complication rate. Surgery operative time, lengths of hospital stay and neurologic symptoms did not differ significantly between two treatments. CONCLUSIONS: rhBMP-2 chosen in ACDF offered higher fusion, but also higher complication rate with more dysphagia and wound infections than non-rhBMP-2. To gain the efficacy and safety, rhBMP-2 dosing recommendations for ACDF would be better < 0.7 mg/level. Moreover, rhBMP-2 may be an option to improve nonunion in high risk of multi-level ACDF. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: This article indicated that the product development of facilities used in ACDF, the dose of rhBMP-2 may be lower than 0.7 mg/level was enough to gain the good fusion rates. However, the complications were higher in patients used rhBMP-2, therefore the manufacturers should pay attention to mitigate such side effects.

Terahertz metamaterial with broadband and low-dispersion high refractive index.

A broadband and low-dispersion high refractive index (HRI) metamaterial formed by symmetrically etching two identical metasurfaces on both sides of a dielectric slab has been numerically and experimentally demonstrated in the terahertz region. The unit cell of the metasurface is a Jerusalem cross surrounded by a square metal ring, in which there are two magnetic resonances and one electric resonance. The proposed metamaterial simultaneously possesses high effective permittivity and permeability in broadband frequencies, since the multiple resonances result in a significant bandwidth expansion of a HRI. The simulation results reveal that the refractive index of the proposed metamaterial reaches up to 27 in the frequency range of 0.39-0.65 THz, and the relative bandwidth is about 44%. Furthermore, the fluctuation of the refractive index in this frequency band is less than 6%, showing a good low-dispersion characteristic. We also fabricated a sample to verify this HRI property. Experimental results are in good agreement with numerical simulations. This broadband HRI metamaterial is desirable in many fields, such as in high-resolution imaging and optical communications.

[Concentrations, Sources, and Dry Deposition Fluxes of Different Forms of Phosphorus in Qingdao Aerosols in Summer].

Total suspended particulate (TSP) samples were collected in Qingdao from June to July 2016. Different forms of phosphorus in these samples-including total phosphorus (TP), dissolved phosphorus (DP), dissolved inorganic phosphorus (DIP), and dissolved organic phosphorus (DOP) were analyzed to investigate their distribution characteristics and sources, as well as their dry deposition fluxes. Results showed that the mass concentration of TP in aerosols was (49.3±30.6) ng·m-3, and the concentration of DP was (15.5±10.4) ng·m-3, accounting for 30.9%±11.0% of TP. DIP dominated in dissolved state P, contributing about 60%. The sources of different forms of P were analyzed, showing that the P in Qingdao aerosols in summer was derived from both crustal and anthropogenic sources, with the latter including biomass burning and agricultural fertilization. TP was mainly derived from soil sources, which contributed 38%, while the contribution of agricultural activities and industrial sources was about 20%. DIP in DP was mainly derived from agricultural activities and combustion sources, with contributions of 51% and 24%, respectively. DOP was mainly derived from soil sources and agricultural activities, contributing 41% and 27% respectively. The dry deposition flux of TP in Qingdao was (51.7±31.7) µg·(m2·d)-1, of which 23.2%±8.2% was the water-soluble fraction. DOP in the total dry deposition flux of DP was non-negligible, accounting for 40%. The atmospheric deposition of soluble P would support phytoplankton carbon production of (0.5±0.3) mg·(m2·d)-1, contributing about 1% to new productivity in the Yellow Sea.

[Concentration, Solubility, and Dry Deposition Flux of Trace Elements in Fine and Coarse Particles in Qingdao During Summer].

PM2.5 and total suspended particulate (TSP) samples were synchronously collected in Qingdao from June to July 2016. The total and water-soluble concentrations of 12 trace elements in these samples were analyzed to investigate their distribution characteristics in fine and coarse particles as well as their dry deposition fluxes. The results showed that the total mass concentrations of Al, Fe, Sr, Mn, and Ba, which are expected to mainly originate from crustal sources, were generally distributed in the coarse particles, and the part mass in the coarse mode accounted for 55%-60% of their total concentrations. Cr, Ni, V, Zn, Pb, As, and Cd, which mainly originate from anthropogenic contributors, generally existed in fine particles where the part mass accounted for 65%-85% of their total concentrations. The soluble mass concentrations of trace elements, whether from crustal or anthropogenic sources, were mainly distributed in the fine particles. The proportions of Al, Fe, Mn, and Ba in soluble mass concentration existing in the fine particles were 50%-80% and 70%-90% for Cr, Ni, V, Zn, Pb, As, and Cd. The solubility of trace elements was higher in fine particles than in coarse particles. The soluble concentrations of trace elements exhibited a positive correlation with acid compounds, and the solubility exhibited a negative correlation with pH in the fine particles, implying that acidification processes play a key role in determining the solubility of trace elements in fine particles. The soluble fractions in the total dry deposition flux of Al and Fe were only 1%-2%; that of Sr, Ba, Cr, and Pb were about 30%-40%; and that of Mn, Ni, V, Zn, As, and Cd were about 50%-60%. The atmospheric deposition of soluble Fe supported phytoplankton carbon production of (194±150) mg·(m2·d)-1, contributing about 10% of the primary productivity in the Yellow Sea.

[Distribution of Oxalate in Atmospheric Aerosols and the Related Influencing Factors in Qingdao, During Winter and Spring].

A total of 119 total suspended particle (TSP) samples were collected in Qingdao from December 2012 to April 2013. Concentrations of oxalate in TSP were measured to investigate the distributional characteristics of oxalate and the related influencing factors, in winter and spring. The concentrations of oxalate in Qingdao aerosols were 31-370 ng·m-3 with an average of 104 ng·m-3 in winter, and 11-1926 ng·m-3 with an average of 400 ng·m-3 in spring, with a significant difference between the concentrations in the two seasons. Different weather conditions affected the distribution of oxalate in aerosols. The oxalate concentration in TSP was the highest in the hazy days, followed by that in the dusty days, while this concentration in foggy days was close to that in the clear days, and the lowest concentration of oxalate appeared in the rainy days. Oxalate in Qingdao aerosols exhibited a significant positive correlation with temperature and solar radiation, suggesting that the secondary production of oxalic acid via photochemical oxidation has an important contribution to the oxalate concentrations in aerosols. The mechanisms of secondary formation of oxalate in aerosols in winter and spring are possibly different, with the aqueous phase oxidation process predominating in winter and the gas-phase oxidation-driven process predominating in spring. The results of PMF source analysis also showed that the secondary formation is the main source of oxalate in Qingdao aerosol, and its contribution to oxalate production is nearly 45% in winter and 70% in spring. The concentration of oxalate in spring aerosol was significantly higher than that in winter aerosol, the main reason of which was that temperature and solar radiation in spring were significantly higher than those in winter, promoting the secondary formation of particulate oxalate.

[Concentrations and Solubility of Trace Elements in Atmospheric Precipitation in Qingdao].

Thirty-five atmospheric precipitation samples were collected at an urban site in Qingdao from June 2016 to May 2017. The total and soluble concentrations of eight trace elements in the samples were determined, and the variable characteristics of the concentrations and solubility of trace elements, as well as the factors affecting the solubility of trace elements in atmospheric precipitation, have been discussed. Based on the overall data, the total concentrations of the trace elements were found to be in the order Al > Fe > Zn > Mn > Ba > Pb > Sr > V, but the soluble concentrations of the trace elements were in the order Zn > Al > Mn > Fe > Ba > Sr > Pb > V. Solubility was about 5% for the crustal elements Al and Fe, and the solubility of the elements affected by anthropogenic sources was relatively higher, 10%-40% for Pb and Ba, 20%-60% for Mn and Sr, and nearly 55% for Zn and V. The total and soluble concentrations of the trace elements were higher in winter and spring than in summer and autumn, but element solubility in spring was the highest. During continuous rainfall, the total concentrations of trace elements in precipitation decreased appreciably, but the variation trend of the solubility of trace elements was not consistent during the different rainfall processes. The variation in pH was the main factor controlling the solubility of trace elements in precipitation.

[Concentrations of Acidic Gases, Ammonia and Related Water-Soluble Ions in PM2.5 and Gas-Particle Partitioning in Qingdao].

Fifty-eight samples were collected in Qingdao from November to December 2012 using a PM2.5 sampler. Concentrations of acidic gases, ammonia and their partner ions in PM2.5 were determined, and the correlation between concentrations and the gas-particle partitioning were analyzed. The averaged concentrations of HNO3, HNO2, HCl, SO2 and NH, in atmosphere samples of Qingdao were 1. 36, 1. 64, 1. 46, 27. 58 and 2. 95 µg.m-3, respectively, for the concentrations of NO3-, NO2, Cl-, SO(4)2- and NH: in PM2, were 6. 49, 0. 12, 1. 95, 9. 36 and 6. 04 µg.m-3, respectively. When the measurements made in haze days, compared to those made in clear days, the concentration of these ions in PM2.5 increased more than those of acidic gases and ammonia; In foggy days, the concentrations of gases were lower than those in clear days except HNO2, while the reverse was true for the concentrations of all particulate species in PM2.5. During whole study period, the NH3 level was high and the NH4+ in PM2.s in Qingdao was mainly present as (NH4)2SO4. The analysis results suggested that formation of N03 were mainly determined by HNO3. To further explore the control factors of these species in PM2.5, the thermodynamic equilibrium model of ISORROPIA I was employed. Our sensitivity tests showed that the formation of NH4+ was less sensitive to the change of total NH3 (TNH3), but sensitive to the changes of total H2 SO4(TSO4) and total HNO3 (TNO3). The formation of NO3- and SO(4)2- was sensitive to the changes of TNO3 and TSO4, respectively. Taken together, our findings implied that the reduction of TNO3 and TSO4 rather than TNH3 appears to be more effective in lowering mass concentrations of PM2.5 in Qingdao.

[Seasonal distribution of water-soluble inorganic ions in the atmospheric aerosol in Qingdao].

To collect comprehensive information on the characteristics and sources of water-soluble ions in the atmospheric aerosol in Qingdao, samples of total suspended particles (TSP) were collected from January to December 2008, and the concentrations of the major water-soluble inorganic ions were analyzed using ion chromatography. The results showed that SO4(2-), NO3-, NH4+ and Cl- were the dominant water-soluble ions in TSP, the sum of the four accounting for 86.9% of water-soluble ions in mass concentration. TSP and water-soluble inorganic ions showed obvious seasonal variations and there were a variety of sources. The mass concentrations of Na+, NH4+, Ca2+, F- and Mg2+ were highest in winter and lowest in summer. The concentrations of K+ and PO4(3-) were highest in autumn and lowest in summer. NO3-, Cl- and SO4(2-) concentrations had the highest values in spring, winter, and spring, respectively. Different weather conditions had great influence on the concentrations of TSP and water-soluble ions. The mass concentrations of TSP were highest in dust weather followed by haze, smog, fog and sunny days. The average mass concentrations of Na+ , Mg2+, Ca2+, F- , Cl- and PO4(3-) were highest in smog days while the other ions in haze days.

[Contribution of water soluble organic nitrogen to total nitrogen in atmospheric aerosols in Qingdao].

Organic nitrogen (ON) is a quantitatively important component of reactive nitrogen in atmospheric aerosols. Deposition of ON in seawater from atmosphere could enhance primary productivity, as well as with the changes in the phytoplankton community composition. 64 total suspended particles (TSP) samples collected at Qingdao from January to December in 2008 were applied to analyze the concentrations of water soluble organic nitrogen in aerosols. Concentrations of ON in Qingdao aerosols ranged from 30 to 2073 nmol x m(-3) (100-12 157 micromol x g(-1)), with the highest values occurring in December, followed in March and April and the lowest values in June to September. ON mean concentration in TSP in 2008 was 430 nmol x m(-3) (2 323 micromol x g(-1)). The contribution of ON to total nitrogen (TN) was (37.5 +/- 21.6)%, with the maximum presenting in December and the minimum in September. The distribution of organic nitrogen in aerosols was significantly affected by the weather conditions. During haze and fog episodes, the concentrations of ON in the aerosols were 789 nmol x m(-3) and 412 nmol x m(-3), respectively, 4 times and twice higher than that during clear episodes. However, the particle mass concentrations in haze and fog days were comparable with that in clear days. During dust episodes, the concentration of particles was 5 times higher than that during clear episodes while ON concentration slightly enhanced 0.4 times. The ON concentration in aerosols after raining was 57 nmol x m(-3), decreased 80% than that before raining due to the efficient wet scavenging.

Outcome of thoracolumbar burst fractures treated with indirect reduction and fixation without fusion.

Indirect reduction and fixation is not a new method in the treatment of thoracolumbar burst fractures but the indications and efficacy are controversial. The current study was designed to evaluate the efficacy of indirect reduction without fusion. Sixty-four patients with single-level thoracolumbar burst fractures were identified and treated by this method. The outcome was analyzed by the Frankel method, radiographic measurements, and at the latest follow-up the Denis Pain Scale and Oswestry disability index (ODI) were used to assess back pain and functional outcome. The average follow-up period was 40.1 months. The anterior vertebral height (AVH) was corrected from 55.2 to 97.2% post-operatively and decreased to 88.9% after hardware removal. The posterior vertebral height (PVH) increased from 88.9 to 99.1% post-operatively and decreased slightly after implant removal to 93.7%. The average pre-operative canal compromise was 41.4%, which decreased to 13.7% at last follow-up. Except for three paraplegic patients, neurological status significantly improved or stayed normal in the study's remaining 61 patients. Fifty-two of sixty-four patients had excellent or good function. At latest follow-up the average ODI score was 16.7 and the Denis pain score improved in all patients but one. Indirect reduction and fixation can not only restore vertebral column structure but also, more importantly, patients' functional outcome.

[Distribution of atmospheric particulate inorganic nitrogen in different weather conditions in the heating period in Qingdao].

The atmospheric aerosol samples were collected before and in the heating period during October 2007-April 2008 in Qingdao coastal region, and inorganic nitrogen components were analyzed using IC (Ion Chromatography). The results showed that the concentration of aerosol particles and particulate inorganic nitrogen components (NH4+, NO3-) were increased from 137.41 microg/m3, 2.48 microg/m3, 6.95 microg/m3 before to 250.34 microg/m3, 4.43 microg/m3, 10.28 microg/m3 in the heating period respectively. The concentrations of TSP (total suspended particles) and inorganic nitrogen in Qingdao were influenced by different weather conditions. The average concentration of TSP was 181.34 microg/m3 in sunny days during heating period, increased by 32.0% than before. But the nitrate and ammonium showed a value of 5.56 and 1.86 microg/m3 in sunny days, lower than that before heating, which mainly came from secondary aerosols. The average concentrations of TSP, nitrate and ammonium increased were 1-2 times higher in foggy days in heating period due to lower temperature, high humidity and accumulation of pollutants. The concentrations of TSP, nitrate and ammonium decreased in strong winds and temperature drop weather. The size distribution of aerosol particles and inorganic nitrogen, were influenced clearly by heating soot and ash. The size distribution of nitrate showed double peaks with a higher peak in accumulation mode (0.43-0.65 microm) and a lower one in coarse mode (3.3-4.7 microm) before heating, and the peak in the 'accumulation mode' shifted to 0.65-1.1 microm during heating period. NH4(+) -N, a major inorganic nitrogen component in the particulate matter, showed single peak in the "accumulation mode".

[Distributions of dissolved and particulate amino compounds in atmospheric aerosols at Qingdao].

Amino compounds is one class of organic nitrogen compounds that has been measured extensively in aerosols and rainwater. These compounds in atmospheric deposition might have a potential role in marine ecosystem since it can be directly utilizable sources of nitrogen for microorganisms and plants. 66 total suspended particles samples were collected at Qingdao from January to December in 2008. Concentrations of dissolved amino compounds (DAC) and particulate amino compounds (PAC) were analyzed using precolumn fluorescence derivatization with o-phthaldialdehyde and N-isobutyryl-L-cysteine, combined with reverse-phase high performance liquid chromatography. Concentrations of DAC in Qingdao aerosols ranged from 2.4 to 40.9 nmol x m(-3), with highest values occurring in spring, followed in summer and lowest values in autumn and winter. PAC concentration were from 0.7 to 76.1 nmol x m(-3), presenting the seasonal trend of spring > winter > autumn > summer. Compositions of amino compounds in aerosols varied seasonally. By classifying air mass back trajectories during each sampling period, the aerosol samples in Qingdao were mainly influenced by northerly continental source, southerly continental source and marine source. Concentrations of DAC and PAC were found highest in the samples influenced by southerly continental source, followed by northerly continental source and lowest in the samples by marine source. Compositions of amino compounds were also influenced by the sources. Contributions of protein-type to total amino compounds were highest in the aerosols from marine source and lowest in the aerosols from southerly continental source.

[Distributions of inorganic nitrogen species in atmospheric aerosols over the East China Sea].

33 total suspended particle samples and 7 size-segregated particle samples were collected over the East China Sea from Nov. to Dec., 2006, Feb. to Mar., 2007 and May. to Jun., 2008. Concentrations of ammonium, nitrate and nitrite in aerosols were measured to investigate their seasonal variation and size distribution. The concentrations of ammonium in aerosols ranged from 2.6 to 646.9 nmol x m(-3) ,with the higher values observed in winter and spring, and the lower values in summer. Nitrate concentrations were from 5.5 to 281.5 nmol x m(-3), presenting the seasonal trend of winter > spring approximately summer. The concentrations of nitrite were very low, less than 0.5 nmol x m(-3). The relative contributions of nitrogen species to total nitrogen varied seasonally in some extent. The contribution of nitrate was comparable with that of ammonium in winter, while the contribution of ammonium was the predominant in spring and summer. The size distribution of nitrate presented clear monthly changes. Most of nitrate existed in the fine particles less than 2.1 microm in Nov. to Dec., and it predominated in the coarse particles with the size of 1.1-4.7 microm and 2.1-7.0 microm, respectively, in Feb. to Mar. and May. to Jun. The size distributions of ammonium in different months were similar, with one peak presenting in the < 1.1 microm fine particles. The air mass back trajectories analysis indicated that the distributions of inorganic nitrogen in aerosols were significantly influenced by the sources and transport pathways of air mass. Both high nitrogen concentration per unit atmospheric volume (nmol x m(-3)) and per unit mass particle (micromol x g(-1)) occurred when the air mass passed over severe pollution region. Both low concentration in atmosphere and particle occurred when the air mass came from clean marine atmosphere. Lower concentration in atmosphere and higher concentration in particle occurred when the air mass originated from the continent and transported long distances over the sea.

Design and analysis of metal-dielectric nonpolarizing beam splitters in a glass cube.

A novel design of a 25-layer metal-dielectric nonpolarizing beam splitter in a cube is proposed by use of the optimization method and is theoretically investigated. The simulations of the reflectance and differential phases induced by reflection and transmission are presented. The simulation results reveal that both the amplitude and the phase characteristics of the nonpolarizing beam splitter could realize the design targets, the differences between the simulated and the target reflectance of 50% are less than 2%, and the differential phases are less than 3 degrees in the range of 530 nm-570 nm for both p and s components.

[Urea in aerosol and rainwater over the East China Sea in winter and spring].

Organic nitrogen is a quantitatively important component of fixed nitrogen in atmospheric aerosol and rainwater. Urea as a possible candidate of organic nitrogen component might have a significant influence to the marine ecosystem since its bioavailability and broad range of natural and anthropogenic sources. 23 total suspended particulate samples, 4 size-segregated particles samples and 10 rainwater samples collected over the East China Sea from Nov. to Dec., 2006 and Feb. to Mar., 2007 were applied to analyze the concentrations of urea, nitrate and ammonium in aerosols and rainwater, respectively. In winter and spring, the concentrations of urea nitrogen were from 0.2 nmol m(-3) to 17.7 nmolx m(-3) and 6.5 nmol x m(-3) to 14.6 nmol x m(-3) in bulk aerosols, respectively and the corresponding concentrations were from 7.8 miromol x L(-1) to 18.1 micromol x L(-1) and 12.1 micromol x L(-1) to 35.3 micromol x L(-1) in rainwater. In both aerosols and rainwater over the East China Sea, the concentrations of urea nitrogen were higher in spring than those in winter. Urea nitrogen in aerosols contributed about 5% to the three measured nitrogen species and it was about 20% in rainwater. The size distribution of urea was markedly different from those of nitrate and ammonium,which had no pronounced difference among cascade stages. A slightly enhance urea contribution presented in the range of 0.43-0.65 microm in spring, which was 19.8%. In contrast, an enhancement presented in the range of 3.3-4.7 microm in winter, which was 19.8%. Factor analysis indicated that the sources of urea in aerosols were dominated by wind-blown soils in winter and sublime of urea in soils in spring, respectively.

Fluoroscopically-guided indirect posterior reduction and fixation of thoracolumbar burst fractures without fusion.

This article presents an evaluation of fluoroscopy for indirect, posterior reduction and fixation of thoracolumbar burst fractures. A prospective study of 25 patients with thoracolumbar burst fractures who underwent C-arm machine-guided posterior indirect reduction and short segment fixation without fusion is described. No laminotomies were performed. All patients had a mean follow-up of 30.4 months. At postoperative review, the average anterior and posterior vertebral heights were corrected from 57.9% to 99.0% and 89.0% to 99.5%, respectively. The Cobb angle was corrected from 18.4 degrees to 0.17 degrees . The canal compromise ratio was improved from 35.2% to 8.6%. In all 25 cases, neurological status was intact at last follow-up. Fluoroscopy guidance is an effective method to accomplish indirect reduction and fixation. Reduction was confirmed on lateral fluoroscopic views by looking for a "one-line sign," which is the reconstitution of the posterior border of the vertebral body.