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We report the development of an optical feedback linear cavity-enhanced absorption spectroscopy instrument for HO2 detection using a distributed feedback (DFB) diode laser operating at 1506 nm. A direct and accurate method of reflectivity measurement based on the analysis of cavity mode signals was proposed. A differential circuit was used to judge the zero crossing point of the optical feedback cavity mode in the center of the frequency locking region, and shift the laser operating current to the non-resonant region. In this way, a ring-down signal was obtained with a time of 17.9 μs, corresponding to an effective absorption pathlength of 5.37 km. Combining the standing wave condition, the relationship between cavity length and drive voltage of the PZT mounted on the cavity rear mirror is translated into a correlation between the transmitted light wavenumber and the PZT voltage. The spectral resolution was improved from 290 MHz to 97 MHz by precisely tuning the PZT voltage. The achieved detection sensitivity of the system was 7 × 10− 10 cm− 1 with a data acquisition time of 10.6 s. The absorption spectrum of HO2 at 6638.205 cm− 1 was measured at a cell pressure of 50 mbar with a detection limit of 3.24 × 109 molecule/cm3. [ABSTRACT FROM AUTHOR]

Nonunion is a challenging complication of fractures for the surgeon. Recently the Lys-Asp-Glu-Leu (KDEL) endoplasmic reticulum protein retention receptor 2 (KDELR2) has been found that involved in osteogenesis imperfecta. However, the exact mechanism is still unclear. In this study, we used lentivirus infection and mouse fracture model to investigate the role of KDELR2 in osteogenesis. Our results showed that KDELR2 knockdown inhibited the osteogenic differentiation of mBMSCs, whereas KDELR2 overexpression had the opposite effect. Furthermore, the levels of active-β-catenin and phospho-GSK3β (Ser9) were upregulated by KDELR2 overexpression and downregulated by KDELR2 knockdown. In the fracture model, mBMSCs overexpressing KDELR2 promoted healing. In conclusion, KDELR2 promotes the osteogenesis of mBMSCs by regulating the GSK3β/β-catenin signaling pathway. [ABSTRACT FROM AUTHOR]

As a potential electrode material for lithium-ion batteries, Ga2O3 has high theoretical specific capacity and low lithium storage potential. Still, the bulk expansion efficiency and poor reaction kinetics during the reaction process hinder performance improvement. This paper successfully synthesised the Ga2O3 NPs@CF composite electrode with network core–shell structure using the electrospinning method. Carbon coating effectively alleviates the volume expansion of Ga2O3 during the reaction process. The carbon fibre network structure provides more transport channels for ions, and the Ga2O3 NPs@CF composite electrode shows excellent performance. In the long cycle test, after 500 cycles of 0.5 A/g, the discharge capacity reached 611.04mAh/g, and the capacity retention was 99.8%. At the current density of 0.1 ~ 2A/g, after a periodic cycle, when restored to 0.1A/g, the capacity remains at a high reversible capacity of 677.8mAh/g. [ABSTRACT FROM AUTHOR]

Improving diabetes self-management (DSM) is facing real-world challenges among people with type 2 diabetes mellitus (T2DM) who have a low education level in resource-limited areas. This study aimed to investigate whether diabetes knowledge could predict glycemic levels in people with T2DM in rural China. This analytical cross-sectional study recruited 321 people with T2DM from eight villages by purposive sampling at baseline. After 10 months, 206 patients completed the follow-up survey and HbA1c tests, with a response rate of 64.17% (206/321). Multiple regression analysis was employed to explore the correlation between diabetes knowledge and HbA1c levels. The patient's diabetes knowledge was significantly negatively correlated with HbA1c levels before and after controlling for covariates in both hierarchical multiple regression and multiple logistic regression (p < 0.01). In addition, other influencing factors, including sex, age, marital status, employment status, income, and HbA1c levels at baseline, were also identified. Diabetes knowledge could predict HbA1c levels significantly among patients with low education levels in rural China. Therefore, interventions on improving diabetes knowledge need to be strengthened for patients in rural China so that they can improve their health outcomes and reduce the disease burden. [ABSTRACT FROM AUTHOR]

Chaperone-mediated autophagy (CMA) plays multiple roles in cell metabolism. We found that lysosome-associated membrane protein type 2A (LAMP2A), a crucial protein of CMA, plays a key role in the control of mesenchymal stem cell (MSC) adipo-osteogenesis. We identified a differentially expressed CMA gene (LAMP2) in GEO datasets (GSE4911 and GSE494). Further, we performed co-expression analyses to define the relationships between CMA components genes and other relevant genes including Col1a1, Runx2, Wnt3 and Gsk3β. Mouse BMSCs (mMSCs) exhibiting Lamp2a gene knockdown (LA-KD) and overexpression (LA-OE) were created using an adenovirus system; then we investigated LAMP2A function in vitro by Western blot, Oil Red staining, ALP staining, ARS staining and Immunofluorescence analysis. Next, we used a modified mouse model of tibial fracture to investigate LAMP2A function in vivo. LAMP2A knockdown in mMSCs decreased the levels of osteogenic-specific proteins (COL1A1 and RUNX2) and increased those of the adipogenesis markers PPARγ and C/EBPα; LAMP2A overexpression had the opposite effects. The active-β-catenin and phospho-GSK3β (Ser9) levels were upregulated by LAMP2A overexpression and downregulated by LAMP2A knockdown. In the mouse model of tibial fracture, mMSC-overexpressing LAMP2A improved bone healing, as demonstrated by microcomputed tomography and histological analyses. In summary, LAMP2A positively regulates mMSC osteogenesis and suppresses adipo-osteogenesis, probably via Wnt/β-catenin/GSK3β signaling. LAMP2A promoted fracture-healing in the mouse model of tibial fracture. Key messages: • LAMP2 positively regulates the mBMSCs osteogenic differentiation. • LAMP2 negatively regulates the mBMSCs adipogenic differentiation. • LAMP2 regulates mBMSCs osteogenesis via Wnt/β-catenin/GSK3β signaling pathway. • LAMP2 overexpression mBMSCs promote the fracture healing. [ABSTRACT FROM AUTHOR]

Background: Epidermal growth factor-like domain protein 7 (EGFL7) is a secreted protein that is differentially expressed in the bone microenvironment; however, the effect of EGFL7 on the osteogenesis of human bone marrow mesenchymal stem cells (hBMSCs) is largely unknown. Methods: EGFL7 expression in the fracture microenvironment was analyzed based on the Gene Expression Omnibus (GEO) database. Knockdown of EGFL7 by small interfering RNA (siRNA) and in vitro stimulation with recombinant human EGFL7 (rhEGFL7) protein were used to assess alterations in downstream signaling and changes in the osteogenic differentiation and proliferation of hBMSCs. A γ-secretase inhibitor was used to further explore whether inhibition of Notch signaling rescued the osteogenic-inhibitory effect of EGFL7 knockdown in hBMSCs. A femoral defect model was established to verify the effect of recombinant mouse EGFL7 on bone healing in vivo. Results: EGFL7 expression increased during hBMSC osteogenesis. Knockdown of EGFL7 impaired hBMSC osteogenesis and activated Notch1/NICD/Hes1 signaling. rhEGFL7 promoted hBMSC osteogenesis and downregulated Notch1 signaling. The osteoblast-inhibitory effect of EGFL7 knockdown was rescued by Notch1 signaling inhibition. Recombinant EGFL7 led to enhanced bone healing in mice with femoral defects. Conclusions: EGFL7 promotes osteogenesis of hBMSCs partly via downregulation of Notch1 signaling. [ABSTRACT FROM AUTHOR]

A CaO-Al2O3-B2O3-SiO2 (CABS) glass/Al2O3 LTCC substrate material with high flexural strength for microwave application has been successfully prepared through the avenue of investigating the effects of B2O3 in CABS glass and different glass/ceramic mass ratios on sintering shrinkage behavior, phase composition, microstructure, mechanical properties, and microwave dielectric properties of CABS glass/Al2O3 composites. The results show that adding an appropriate amount of B2O3 can lower the softening temperature of CABS glass and control the interfacial reaction between CABS glass and Al2O3, which is beneficial to the densification of CABS glass/Al2O3 and improves the microwave dielectric and mechanical properties. When the content of B2O3 is 22 wt% (in the CABS glass), the CABS glass/50 wt% Al2O3 sample sintered at 875 °C for 2 h exhibits the best comprehensive properties with the dielectric constant (εr) of 6.95, dielectric loss (tanδ) of 4.56 × 10–3 (~ 10 GHz) and flexural strength of 223 MPa. [ABSTRACT FROM AUTHOR]

Baiyangdian Lake is a typical and largest multi-habitat lake in the North plain of China. To understand the generation and transmission of antibiotics resistance genes (ARGs) in multi-habitat lakes, the contents of nutrients (TC, TOC, TN, TP and TS), heavy metals (Zn, Cr, Ni, Cu, Pb, As, Cd and Hg), 22 antibiotics, 16S-rRNA(16S), Class I integron (intI1) and 20 ARGs were determined. Samples were taken from the Fuhe river, river estuaries, reed marshes, living area, fish ponds and open water of Baiyangdian Lake. The results showed that quinolones were the main pollutants in six habitats, and the content range was ND-104.94 ng/g. Thereinto, aac (6') -IB, blaTEM-1, ermF, qnrA, qnrD, tetG, sul1, sul2 and tetM were detected in all the analyzed samples. The absolute abundance of sul1 was the highest (5.25 × 105 copies/g-6.21 × 107 copies/g) in most of the samples. In these different habitats, the abundance of antibiotics and ARGs in river estuary was the highest, and that in reed marshes was the lowest. There was a significant positive correlation between the abundance of heavy metals (Cu, Pb, Zn, Ni, Cd, Hg) and the absolute abundance of 11 ARGs (P < 0.01). Redundancy analysis showed that Cu, Zn, intI1, TP and macrolides were the important factors affecting the distribution of ARGs. Our finding provides a more likely driving and influencing factor for the transmission of ARGs in lakes with complex and diverse habitats. [ABSTRACT FROM AUTHOR]

In this work, A-site Nd doped BaTiO3 ceramics in the form of Ba1−xNd2x/3TiO3 with a wide substitution level range of x = 0–0.2 have been prepared via solid-state reaction method. Powder X-ray diffraction results reveal that Nd is completely incorporated into the BaTiO3 lattice in all specimens. Further analyses based on Rietveld refinement suggest that tetragonal and pseudo-cubic phases coexist in Ba1−xNd2x/3TiO3 ceramics with x ≤ 0.06, and the amount of tetragonal phase is raised with the increase of x value. When x value is larger than 0.08, only pseudo-cubic is observed. The generated V Ba ″ , Nd Ba · and V O · · defects, which are identified by X-ray photoelectron spectra, make the grain size displays a tendency of decrease first mainly due to the pining effect, and then increase ascribed to the accelerate of mass diffuse. By introducing such wide range of substitution level, Ba1−xNd2x/3TiO3 ceramics with colossal dielectric constant (x = 0.08), temperature-stable dielectric properties (x = 0.15), especially relaxor behavior (x = 0.20) noticed for the first time, are, respectively, received, which is closely related to the variation of phases and defects induced by the addition of Nd. This study may provide a special idea to modify BaTiO3 to satisfy diversified applications by single element with a wide doping range, and could lay the foundation of future works focusing on the various potential applications of Ba1−xNd2x/3TiO3 ceramics. [ABSTRACT FROM AUTHOR]

Through the avenue of adjusting the thermal properties of BaO–MgO–Al2O3–SiO2 (BMAS) glass-ceramic by changing the MgO/BaO ratio, a BMAS glass-ceramic with the MgO/BaO ratio of 1:2 has been obtained, which shows satisfactory softening and crystalline behavior. Then, this BMAS glass-ceramic is used to lower the sintering temperature of Al2O3 ceramic. After systematic research on the sintering and physical properties of BMAS /Al2O3 composite with different glass-ceramic content, we find that when the content of BMAS glass-ceramic is 50%, the composite presents adorable comprehensive properties: dielectric constant of 5.40 @ ~10 GHz, dielectric loss of 1.91 × 10− 3 @ ~10 GHz and bending strength of 143 MPa, meeting the requirement of LTCC substrate material for microwave application. [ABSTRACT FROM AUTHOR]

The Ca0.245Li0.325Nd0.395Ti1−xSnxO3 (x = 0–0.12) ceramics were prepared by the traditional solid-state reaction method. The effects of Sn4+ substitution for Ti4+ on the phase composition, microstructure, and microwave dielectric properties of Ca0.245Li0.325Nd0.395Ti1−xSnxO3 (CLNTSx) were investigated in this work. The X-ray diffraction results showed that the ceramics had a single orthorhombic perovskite structure when x = 0–0.09. However, a secondary phase SnO2 was observed with x > 0.09. The SEM micrographs indicated that the proper Sn4+ substitution for Ti4+ promoted the grain growth and homogenization. The analysis results of Raman spectroscopy revealed the correlation between vibration modes and microwave dielectric properties of CLNTSx ceramics with different Sn4+ contents. The degree of cation order was related to the full width at half maximum (FWHM) of the Raman spectrum, and a lower FWHM value indicates higher cationic order and Q × f0 value. The excellent microwave dielectric properties with εr = 98, Q × f0 = 3320 GHz, and τf = 2.6 ppm/°C were obtained in the ceramics with x = 0.09 sintered at 1350 °C for 4 h. [ABSTRACT FROM AUTHOR]

In non-dense solid electrolytes, the arrangements of closed pores are rarely periodical repeating, while a periodical repeating assumption would save the cost of modeling and structural interpreting. In this paper, we have made a partially delocalized model to describe the non-periodical repeating pores, where the deviation of pores was confined inside the "cell" finally assembling the whole non-dense solid electrolyte. The quantitative measurement, order parameter S , depicting the degree of order, has also been clearly defined in this paper. The order parameter was defined to be within the range of [0,1]; with the increment of it, the arrangement of closed pores of the whole system was more ordering (i.e., pores arrangement is closer to the periodical repeating structure). Furthermore, with the aid of the finite element modeling (FEM) method, the ionic conductivity has been related to the degree of ordering of the pores: though ordering could enhance the ionic conductivity, it is still possible to model the solid electrolyte by the periodical repeating structure which might impart additional 1% error. Finally, the probability and effect on ionic conductivity of disordering assisted pore impingement have been investigated, indicating that the impingement orientation can ameliorate the ionic conductivity, which could be a guidance for the further functional design of the solid electrolyte structure. [ABSTRACT FROM AUTHOR]

In order to solve the problem of nitrous oxide (NOX) removal at low temperatures, the carbon-based zero valent iron (C-ZFe) catalyst was prepared and studied. According to the kinetic study and the obtained kinetic parameters, the De-NOX reactor was designed to provide information for industrial applications. The box-behnken experimental design (BBD) was used to study the performance of C-ZFe, and the optimized operating parameters were obtained as the temperature was 408.15 K, the catalyst bed height was 140 cm (the space velocity was 459 h−1), the concentration of NO was 550 ppm, under which the NOX conversion was 72.7%. A kinetic model based on Langmuir–Hinshelwood (L–H) and Mars Van Krevelen mechanism was used to describe the kinetics for the reduction of NO by C-ZFe at low temperatures. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), surface area and pore size distribution measurements, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) results supported the validity of the model proposed. The gas–solid catalytic kinetic process of NO removal by C-ZFe was a quasi-first-order kinetic reaction, the apparent activation energy was 41.57 kJ/mol, and the pre-exponential factor was 2980 min−1. [ABSTRACT FROM AUTHOR]

BaO–Al2O3–SiO2–B2O3 (BASB) glass-ceramic designed to replace the glass additive in traditional glass + ceramic composite system as LTCC material has been investigated. The influence of additive amount of glass former B2O3, network modifier BaO and network intermediate Al2O3 on the thermodynamic properties of BASB glass-ceramics is studied. The results show that the increase of both B2O3 and BaO can lower the softening and crystallization temperatures of the glass-ceramic. At the same time, the increase of BaO content leads to the reduction in sintering shrinkage rate. The addition of Al2O3 can decrease the crystallization temperature, but the softening temperature will exhibit a complicated variation of decreasing at first and then rising. Based on the aforementioned results, an optimum BASB glass-ceramic consisting of 13 mol% B2O3, 24 mol% BaO, 12 mol% Al2O3, 50 mol% SiO2, 1 mol% ZrO2 and 1 mol% Li2O is produced, with the softening temperature of 650 °C, main crystalline phase of BaAl2Si2O8 after being sintered at 850 °C and the crystallization activation energy of 292.25 kJ/mol. The received glass-ceramic is then employed as sintering aid to fabricate low-temperature-sintered BASB glass-ceramic + Al2O3 ceramic composite. The 55 wt.% BASB + 45 wt.% Al2O3 composite sintered at 850 °C shows attractive comprehensive properties with a density of 2.79 g/cm3, dielectric constant of 5.88@10 GHz and dielectric loss of 1.54 × 10–3@10 GHz, which makes it a good candidate for microwave LTCC substrate application. [ABSTRACT FROM AUTHOR]

The co-firing compatibility between green tape and the Ag electrode is a crucial characteristic in low-temperature co-fired ceramic (LTCC) technology and plays a vital role in improving the performance and application status of LTCC device modules. In this work, we studied the effects of lead content on the glass viscosity, the microstructure, and co-firing compatibility of silver electrode film. It was found that the softening point and viscosity of the glass were decreased, and the wettability between the glass and silver was improved with the increase of the lead content, which promoted the co-firing densification and interfacial bonding between the silver electrode film and the ceramic layer. The film presented the best electrical properties co-firing at 875 °C for 15 min, with the resistivity of 1.21 mΩ/sq. And the film was densified. The sintering interface was clear and well bonded. The results showed that an appropriate lead content in glass could effectively improve the interfacial bonding and the electrical properties during co-fired process, providing a new control methodology for realizing co-fired matching of the silver electrode film with low-temperature co-fired ceramics. [ABSTRACT FROM AUTHOR]

Low-temperature sinterable and low-loss composites consisting of La2O3–B2O3–ZnO glass-ceramics and Al2O3 filler have been investigated. The phase composition of LBZ/Al2O3 composites is closely related to the sintering temperature. When the sintering temperature was 850 °C, the main phases included LaBO3 and La(BO2)3 precipitated from LBZ glass-ceramics, ZnAl2O4 and LaAl2.03(B4O10)O0.54 phases generated by interfacial reactions, and Al2O3 filler. The high content of crystalline phases in the composites indicated the low content of residual glassy phases, which was related to the low loss of the composites at high frequencies, especially at microwave frequencies. The initial sintering temperature and the temperature corresponding to the fastest shrinkage speed of LBZ/40A and LBZ/50A composites were related to the content of LBZ glass-ceramics, and all the composites could be densified at low temperatures. Optimum properties were exhibited for the composite of LBZ glass-ceramic with 50 wt% Al2O3 sintered at 900 °C with a permittivity εr = 7.3 and a dielectric loss tan δ = 1.62 × 10−3 (at 12.1 GHz). The low εr and tanδ coupled with a low sintering temperature, suggesting that the LBZ glass-ceramic/Al2O3 composites had potential to meet the requirements of LTCC substrate materials for high frequencies. [ABSTRACT FROM AUTHOR]

The effects of pores in the non-dense solid electrolyte on the ionic conductivity were performed via finite element modeling (FEM). As the basis, the convergence was studied for the low-density model to ensure accuracy and minimize the computational complexity. The pore distribution parameters (relative density, pore size, and the probability density function of the pore size) were systematically investigated based on the converged model. Relative density, the variable mostly researched, was determined to have a linear improvement on the ionic conductivity, quantitatively justifying that the densification process can enhance the ionic-conducting behavior of solid electrolytes. By contrast, at a given relative density for one-point distributed pores, pore size rarely affects ionic conductivity. For non-uniformly distributed solid electrolytes, the ionic conductivity showed a strong dependence on the probability density function (PDF) of the pore size distribution, which could be either improved or reduced. Beyond the traditional method aiming to the densification of solid electrolyte, this paper provides a novel guide to ameliorate the ionic conductivity through the optimization of the pore distribution function. [ABSTRACT FROM AUTHOR]

Baiyangdian Lake (BYD), a large shallow lake in North China, has complex water landscape patterns that are underlies spatial variations in water quality. In this study, we collected 61 water samples from three water landscapes (reed littoral zones, fish ponds, and open water) and analyzed them for water quality parameters, such as dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP). Water landscape distribution (determined using remote sensing imagery) was then used to assess correlations between water quality parameters and water landscape proportion in differently scaled buffer zones. There was substantial variation across all subareas, with TN and TP concentrations ranging from 0.90 to 4.10 mg/L and 0.06 to 0.18 mg/L, respectively, in class IV of water quality as a whole. Spatial variations in water quality were mainly caused by water landscape distribution and external nutrient inputs. There were negative correlations between DOC, TN, and TP concentrations and the area proportion of reed littoral zones in the 300 and 500 m buffers. In contrast, DOC, TN, and TP concentrations were significantly positively correlated with the area proportion of fish ponds in the 100 m buffer. Furthermore, compared with reed littoral zones, a lower ratio of nitrogen to phosphorus and a higher proportion of dissolved organic nitrogen and tyrosine-like proteins were found in fish ponds. These effects were mainly attributed to the development of internal sediment loadings due to nutrient exchange across the sediment–water interface. Therefore, dredging-based sediment removal from fish ponds should be considered to suppress internal phosphorus loading and accelerate recovery of the BYD ecosystem. [ABSTRACT FROM AUTHOR]

Background: Cerebral autoregulation plays an important role in safeguarding adequate cerebral perfusion and reducing the risk of secondary brain injury, which is highly important for patients in the neurological intensive care unit (neuro-ICU). Although the consensus white paper suggests that a minimum of 5 min of data are needed for assessing dynamic cerebral autoregulation with transfer function analysis (TFA), it remains unknown if the length of these data is valid for patients in the neuro-ICU, of whom are notably different than the general populations. We aimed to investigate the effect of data length using transcranial Doppler ultrasound combined with invasive blood pressure measurement for the assessment of dynamic cerebral autoregulation in patients in the neuro-ICU. Methods: Twenty patients with various clinical conditions (severe acute encephalitis, ischemic stroke, subarachnoid hemorrhage, brain injury, cerebrovascular intervention operation, cerebral hemorrhage, intracranial space-occupying lesion, and toxic encephalopathy) were recruited for this study. Continuous invasive blood pressure, with a pressure catheter placed at the radial artery, and bilateral continuous cerebral blood flow velocity with transcranial Doppler ultrasound were simultaneously recorded for a length of 10 min for each patient. TFA was applied to derive phase shift, gain, and coherence function at all frequency bands from the first 2, 3, 4, 5, 6, 7, 8, 9, and 10 min of the 10-min recordings in each patient on both hemispheres. The variability in the autoregulatory parameters in each hemisphere was investigated by repeated measures analysis of variance. Results: Forty-one recordings (82 hemispheres) were included in the study. According to the critical values of coherence provided by the Cerebral Autoregulation Research Network white paper, acceptable rates for the data were 100% with a length ≥ 7 min. The final analysis included 68 hemispheres. The effects of data length on trends in phase shift in the very low frequency (VLF) band (F1.801,120.669 = 6.321, P = 0.003), in the LF band (F1.274,85.343 = 4.290, P = 0.032), and in the HF band (F1.391,93.189 = 3.868, P = 0.039) were significant for 3–7 min, for 4–7 min, and for 5–8 min, respectively. Effects were also significant on the gain in the VLF band (F1.927,129.134 = 3.215, P = 0.045) for 2–8 min and on the coherence function in all frequency bands (VLF F2.846,190.671 = 90.247, P < 0.001, LF F2.515,168.492 = 55.770, P < 0.001, HF F2.411, 161.542 = 33.833, P < 0.001) for 2–10 min. Conclusions: Considering the acceptable rates for the data and the variation in the TFA variables (phase shift and gain), we recommend recording data for a minimum length of 7 min for TFA in patients in the neuro-ICU. [ABSTRACT FROM AUTHOR]

The effect of multiple factors, including La/B ratio and CaO additive, on the efficiency of lanthanum borate glass–ceramics as sintering aids was systematically studied in this work. The sintering and crystallization behavior of binary La2O3–B2O3 glass–ceramics with different La/B ratio were revealed. CaO was then added into the chosen La2O3–B2O3 glass–ceramic to form ternary La2O3–B2O3–CaO system, and the influence of CaO additive on the effect of La2O3–B2O3–CaO glass–ceramics acting as densification flux was detailly discussed. Optimized La2O3–B2O3–CaO glass–ceramic was mixed with Al2O3 filler, and the sintering behavior, phase compositions as well as dielectric properties of received composite were exhibited. As the result, the chosen La2O3–B2O3–CaO glass–ceramic showed much higher efficiency as sintering aids compared with the original La2O3–B2O3 glass–ceramic. And the studied La2O3–B2O3–CaO glass–ceramic/Al2O3 composite had moderate dielectric constant of 7.73 and high Q × f0 value of 11,340 GHz (or low dielectric loss of 9.4 × 10−4) at the frequency of 10.66 GHz, which made it a competitive candidate for LTCC materials. [ABSTRACT FROM AUTHOR]

Gradient index (GRIN) material is widely applied as a kind of special functional material in many practical engineering fields. Accurate knowledge of the GRIN distribution of the material is the key to use GRIN material. Therefore, this paper presents a technique to determine the GRIN using laser beam-based deflection system. In this work, we establish a retrieval model of the GRIN of the slab medium, in which a collection of laser beams from given position transit the medium sample and the exit positions are recorded as measurement information. The Runge–Kutta ray-tracing technique is employed to obtain the ray trajectories, and the stochastic particle swarm optimization algorithm is used to solve the inverse problem to estimate the GRIN of the sample. Moreover, the inverse model we developed is proven to be theoretically reliable via the sensitivity analysis. A series of simulation experiments on determination of the GRIN profiles of the medium samples are performed. The results shows that the GRIN with known functional forms (i.e., linear and sinusoidal expressions) can be inversed accurately, but the estimation of the GRIN without known functional forms fails. Considering that the GRIN profiles are usually unknown beforehand in practice, an improved inverse model in which two collections of laser beams are adopted to transit the sample and the refractive index on the boundary wall is measured by a refractometer to increase the measurement information is proposed. The results indicate that the GRIN without known functional forms can be inversed accurately using the improved inverse model and even can tolerate larger measurement errors, which is of great significance to practical experiments. This investigation proves that the retrieval scheme we developed is accurate and can be regarded as a promising inverse technique. [ABSTRACT FROM AUTHOR]

With the recent boom in unmanned aerial vehicle (UAV) technology, many UAV applications involving complex and risky tasks in military and civilian fields have emerged, such as military strikes and disaster monitoring. Task allocation for UAVs is the process of planning the division of work among UAVs, controlled from ground stations by human operators. This study formulates the UAV task-allocation problem as an extended traveling salesman problem and presents a novel UAV task-allocation model for complex air concentration monitoring tasks. Then, an optimized non-dominated sorting genetic algorithm III (NSGA-III) based on a twin-exclusion mechanism, hierarchical objective-domination operator, and segmented gene encoding (i.e., NSGA-III-TEHOD) is developed to solve complex task-allocation problems involving multiple UAVs, hierarchical objectives, obstacles, and ambient wind. The algorithm is tested in several simulations, and the results demonstrate that the new algorithm outperforms NSGA-III, non-dominated sorting genetic algorithm II (NSGA-II), and genetic algorithm (GA) in terms of efficiency of global convergence and early maturation prevention and is available for the hierarchical objective-optimization problems. [ABSTRACT FROM AUTHOR]

Purpose: Baiyangdian Lake is located in the core of Xiongan New Area and is the largest freshwater lake in the North China Plain with a variety of habitats. Microorganisms are important drivers of material cycle and energy transport in freshwater ecosystems. To understand the biogeochemical circulations in Baiyangdian Lake, the bacterial community structures and influencing factors of surface sediments among the different habitats were investigated. Materials and methods: Samples were taken from five areas of Baiyangdian Lake. The concentration of nutrient elements and bacterial community structures was measured. Results and discussion: The bacterial community structures of different habitats were different and were influenced by the nutrients in surface sediment. Open water areas had the richest abundance of ecological functions, such as phototrophy, sulfur oxidation, sulfite respiration, nitrification, and nitrite respiration. The bacterial community structures among the different habitats were decided by different elements in sediment; sulfur was the key influencing factor of the bacterial community structure in open water; C/N ratio was the key influencing factor of reed marshes; nitrogen and organic carbon were the key influencing factors of river estuary habitat. Conclusions: The bacterial community structures and ecological functions of surface sediments among habitats were different, and the dominant bacteria played an important role in biogeochemical circulations, especially in the carbon and sulfur cycles of Baiyangdian Lake. [ABSTRACT FROM AUTHOR]

Purpose: The distribution and dynamic of residue-derived carbon after incorporation into soil at different fertility levels have been well documented. However, the distribution of maize residue–derived C in particulate organic C (POC) from different types of organic residues in soils of different fertility levels is poorly understood. Material and methods: A 540-day in situ field experiment was carried out. In 2016, three types of 13C-labeled maize residues (root, stem, leaf) were added to brown earth of different fertility levels in Northeast China. 13C-POC content in the soil samples was measured on the 60th, 90th, 180th, and 540th days after in situ incubation. Results and discussion: The results showed that 13C-POC content was significantly higher in high-fertility soil than in low-fertility soil during the whole incubation time. There were significant differences among different types of maize residues at the beginning of 180 days, with stem (0.13 g kg−1) and root (0.11 g kg−1) residues higher than leaf residue (0.08 g kg−1), and sequestration of residue in POC was similar between the roots, stems, and leaves after the 540-day field incubation. The mean residence time and residue POC in soils at each fertility level increased (P < 0.05) with increasing incubation time, with a range from 1.52 to 128.72 years in the high-fertility soil and 1.07 to 60.52 years in the low-fertility soil, but showed no significant differences among different types of maize residue. Conclusions: The results revealed that high-fertility soil was more conducive for new POC accumulation than low-fertility soil, and its sequestration was similar among the roots, stems, and leaves after 540 days. [ABSTRACT FROM AUTHOR]

The sintering behavior and dielectric properties of La2O3–B2O3–CaO–P2O5 (LBCP) glass and La2O3–B2O3–CaO–P2O5 glass/Al2O3 (LBCP/A) composites have been investigated. The results show that the major crystalline phase of LBCP glass–ceramics sintered at 625 °C is low-temperature LaBO3 phase, and it transits to high-temperature LaBO3 phase with the sintering temperature up to 850 °C. With the increase of La/B ratio in LBCP glass, the crystallization tendency of LaBO3 phase increases. LBCP/A composites could be well sintered at 850 °C for 2 h. The bulk density of LBCP/A composites increases with the glass content rising and then decreases owing to foaming. The main crystalline phases of LBCP/A composites are LaBO3, CaAl2B2O7, and Al2O3. Dielectric properties are related to the glass composition and content, which determines the density of the composites. The optimized dielectric properties of LBCP/A composites are dielectric constant of 7.108 and dielectric loss of 1.024 × 10–3 in 50LBCP3/50A, which nicely meet the requirements of LTCC substrate materials. [ABSTRACT FROM AUTHOR]

To relieve the camber of Au/ceramic co-fired structure, investigation on the sintering of gold paste with different constituent material properties was performed in this study. The sintering initial temperature of gold paste was correlated with the gold particle size, the glass softening point and the glass content closely. By adjusted the gold paste sintering shrinkage behaviour the camber evolutions were obviously changed, including the camber direction and the camber degree. When glass content in gold paste was 3 wt% and the softening point was 730 °C, the Au/ceramic co-fired structure exhibited the minimum camber, of which the ht/ho value was 0.96. The results of this work have shown the relationship between the camber evolution of Au/ceramic structure and the sintering shrinkage behaviour of gold paste, which would give an avenue to solve camber in the LTCC application. [ABSTRACT FROM AUTHOR]

Purpose: Subsoil has great potential for increasing soil organic carbon (SOC) stock. Soil compaction decreases the content of SOC in the topsoil layer and leads to the formation of a plow pan in subsoil. However, measures for improving poor soil structure mainly concentrate on topsoil. This study aims to understand the effect of subsoiling management practices on soil aggregation and accumulation of SOC in both topsoil (0–20 cm) and subsoil (20–35 cm). Materials and methods: A field experiment was carried out in a Mollisol in northeastern China. The treatments included conventional tillage (CT), subsoiling tillage (ST), and subsoiling with residue incorporation tillage (SST). Results and discussion: The results showed that in comparison to CT, ST and SST not only had lower subsoil bulk densities (reduced by 9.42% and 13.61%, respectively) but also promoted the formation of macroaggregates (> 250 μm) in both soil layers; thus, soil structure stability increased. In the topsoil layer, the content of the > 53 μm aggregate-associated carbon (C) under ST and SST was greater than that under CT. In the subsoil layer, compared with CT, SST increased the organic C content (increased by 0.73–12.32%) in all the aggregate classes, but ST decreased the content of the < 2000 μm aggregate-associated C (6.09–18.96%) on day 150. The soil structure stability decreased by 13.06% and 22.21% under ST and SST after day 150, respectively, which was probably due to the clayey characteristics of the subsoil. Conclusions: We concluded that subsoiling would only improve the soil structure while increasing the loss of organic C. However, the effect of subsoiling on structure improvement was enhanced by residue incorporation, not only promoting soil aggregation but also increasing SOC accumulation. [ABSTRACT FROM AUTHOR]

The directed energy deposition (DED) process enables the production of near net shape parts in the starting form of either powder or wire melted by a focused energy source, such as laser. The target geometry is then built layer by layer. In theory, engineering components with complex shapes can be fabricated with a single setup using a hybrid CNC machine tool, which has capabilities of both DED and traditional subtractive machining processes. However, the issue of inaccurate DED deposited geometry and insufficient material deposition results in the repetition of the hybrid process to achieve the goal geometric dimension. This paper presents a generalized strategy for different materials that plan DED toolpath for the planar geometric feature to achieve its required final geometric dimension by using only a single hybrid manufacturing cycle based on simulated results and validate the strategy experimentally by using a hybrid CNC machine. [ABSTRACT FROM AUTHOR]

Quantum key distribution (QKD)1,2 offers a long-term solution to secure key exchange. Due to photon loss in transmission, it was believed that the repeaterless key rate is bounded by a linear function of the transmittance, O(η) (refs. 3,4), limiting the maximal secure transmission distance5,6. Recently, a novel type of QKD scheme has been shown to beat the linear bound and achieve a key rate performance of O (η) (refs. 7–9). Here, by employing the laser injection technique and the phase post-compensation method, we match the modes of two independent lasers and overcome the phase fluctuation. As a result, the key rate surpasses the linear bound via 302 km and 402 km commercial-fibre channels, over four orders of magnitude higher than existing results5. Furthermore, our system yields a secret key rate of 0.118 bps with a 502 km ultralow-loss fibre. This new type of QKD pushes forward long-distance quantum communication for the future quantum internet. Phase-matching quantum key distribution is implemented with a 502 km ultralow-loss optical fibre. The fluctuations of the laser initial phases and frequencies are suppressed by the laser injection technique and the phase post-compensation method. [ABSTRACT FROM AUTHOR]

Intraoperative fluoroscopic images, as one of the most important input data for computer-assisted orthopedic surgery (CAOS) systems, have a significant influence on the positioning accuracy of CAOS system. In this study, we proposed to use multi-angle intraoperative fluoroscopy images as input based on real clinical scenario, and the aim was to analyze the positioning accuracy and the error propagation rules with multi-angle input images compared with traditional two input images. In the experiment, the positioning accuracy of the C-arm calibration-based algorithm was studied, respectively, using two, three, four, five, and six intraoperative fluoroscopic images as input data. Moreover, the error propagation rules of the positioning error were analyzed by the Monte Carlo method. The experiment result showed that increasing the number of multi-angle input fluoroscopic images could reduce the positioning error of CAOS system, which has dropped from 1.01 to 0.61 mm. The Monte Carlo simulation analysis showed that for random input errors subject to normal distribution (μ = 0, σ = 1), the image positioning error dropped from 0.29 to 0.23 mm, and the staff gauge positioning error dropped from 1.36 to 1.19 mm, while the tracking device positioning error dropped from 3.41 to 2.13 mm. In addition, the results showed that image positioning error and staff gauge positioning error were all nonlinear error for the whole system, but tracker device positioning error was a strictly linear error. In conclusion, using multi-angle fluoroscopy images was helpful for clinic, which could improve the positioning accuracy of the CAOS system by nearly 30%. Graphical abstract The experiment process and Monte Carlo analysis of spatial positioning accuracy (A: Setup for the experiment; B: The process of Monte Carlo analysis; C: Results). [ABSTRACT FROM AUTHOR]

The ongoing interest in creating a secure global quantum network culminated recently in the demonstration of transcontinental quantum communication1. There is a pressing need to examine the properties attached to a quantum network architecture from multiple perspectives, including physics foundations2, communication security3, the efficient use of resources and innovative technological applications4,5. Here, we present an experimental realization of a five-node quantum network, in which quantum sources at two nodes deliver entangled photon pairs to three measurement nodes. With relevant events between five nodes separated space-like, we demonstrate violation of the Bell inequality and bilocal inequality6, with the locality, measurement independence and quantum source independence loopholes closed simultaneously in a quantum network. This experimental realization may be valuable for the design and implementation of future quantum networks. A violation of bilocal inequality is demonstrated with two truly independent light sources delivering entanglements to three nodes. To this end, the locality, measurement independence and quantum source independence loopholes are closed simultaneously. [ABSTRACT FROM AUTHOR]

The effects of alkaline-earth oxides (SrO, CaO, MgO) on the densification and microwave properties of low-temperature fired BaO–Al2O3–SiO2 (BAS) glass–ceramic/Al2O3 composites have been investigated. By adding alkaline-earth oxides, the softening and crystallization behaviors of BAS-based glass–ceramics, which determine the densification of composites, are sequentially weakened in the order of BAS, SrO–BaO–Al2O3–SiO2 (SBAS), CaO–BaO–Al2O3–SiO2 (CBAS) and MgO–BaO–Al2O3–SiO2 (MBAS). It is also found in the above BAS-based glass–ceramics that the addition of alkaline-earth oxides plays a more profound role on crystallization behavior than on softening behavior, leading to the expansion of the interval between crystallization and softening temperatures (i.e., densification temperature range) to different degrees depending on the type of oxides added. As a result, the microstructures of oxides-modified glass–ceramic/Al2O3 composites (SBAS/Al2O3, CBAS/Al2O3, MBAS/Al2O3) are much denser than those of BAS/Al2O3. The properties of such composites are determined by the interplay among density of microstructure, amount and relative ratio of crystalline and residual glass phases related to the crystallization behavior and interfacial reaction. Detailed analyses suggest that CBAS/Al2O3 achieves optimal properties among all the four composites. Specifically, for CBAS/Al2O3 the dielectric constant, dielectric loss, bending strength and CTE value are 5.81 ± 0.12 (at ~ 10 GHz), (2.04 ± 0.12) × 10−3 (at ~ 10 GHz), 155 ± 7 MPa and 6.58 ± 0.11 ppm/°C, respectively. Our findings may provide a new avenue to design LTCC substrate materials as feasible candidates for microwave devices. [ABSTRACT FROM AUTHOR]

The microstructure and dielectric properties of LaMnO3 (LM) doped BaTiO3 (BT) ceramics have been investigated. By adding LM, (1–x)BT-xLM (x = 0–0.5) ceramics keep in a single-phase solid-solution state, but gradually transform from tetragonal structure to pseudocubic one, and much denser microstructure is obtained. As for dielectric properties, when x ≤ 0.1, the Curie temperature of BT-LM shifts to a lower temperature and the permittivity maximum is lowered with the increase of LM content, which are attributed to the introduction of La2O3 and the degradation of tetragonality, respectively. When x > 0.1, BT–LM presents a typical relaxation behavior. Colossal permittivity appears as x reaches 0.4, which is related to large number of giant electron-pinned defect-dipoles ( Mn 4 + · 2 e - V O · · ) and existence of grain-boundary segregation. Detailed analyses show that 0.5BT–0.5LM possesses the highest permittivity maximum (41,683) and widest temperature range (– 42 to 300 °C) with permittivity larger than pure BT at 100 kHz. Therefore, 0.5BT–0.5LM can be a very promising candidate as colossal permittivity material. [ABSTRACT FROM AUTHOR]

To have a better understanding on the characteristics of La2O3–B2O3–CaO (LBC) glass–ceramics designed for low temperature co-fired ceramic applications, LBC glass–ceramics with La/B ratio changing from 1:6.0 to 1:3.0 were prepared, and the network structure, sinterability, crystalline phase composition and crystallization kinetics of synthesized LBC glass–ceramics were investigated. The increase of La/B ratio would reduce the content of [BO4] units in the network structure, and decrease the glass transition temperature as well as the softening temperature of LBC glass–ceramics. But low La/B ratio of glass could cause serious foaming during sintering process. The change of La/B ratio would influence the position as well as intensity of crystalline peaks on DSC curves, and the composition and microstructure of crystalline phases were also affected. The crystallization activation energies of LBC glass–ceramics were 157.9–498.7 kJ/mol, which raised up with the increase of La/B ratio. [ABSTRACT FROM AUTHOR]

The sintering densification behaviors and crystallization characteristics of CBS glass have been investigated systematically, and a new CBS glass composite system containing two types of CBS glass is reported. The results demonstrated that the sintering densification characteristic of single CBS glass and CBS composite could be divided into two stages: the fast and slow densification stage. The temperature range of the fast densification stage of single CBS glass is quite narrow (680–710 °C), while CBS composite gets a wider one (680–730 °C). In result, more moderate sintering densification process, which benefits the co-firing compatibility with electrode materials, is obtained in CBS composite. The major crystalline phases of the CBS glass and CBS composite were CaSiO3 and CaB2O4. CBS glass sintered at 910 °C for 10 min exhibited excellent microwave dielectric properties of dielectric constant value of 6.4 and quality factor value of 11,110 GHz, while CBS composite showed dielectric properties of dielectric constant value of 6.1 and quality factor value of 10,640 GHz, which meets the requirements for LTCC applications. [ABSTRACT FROM AUTHOR]

New glass-ceramic/ceramic composites based on lead-free low-softening La2O3-B2O3-Al2O3 (LBA) glass-ceramics and Al2O3 fillers were prepared. The phase compositions, microstructure, and dielectric properties of the composites were investigated. LaBO3, La(BO2)3 and LaAl2.03(B4O10)O0.54 including Al2O3 fillers were developed in the LBA glass-ceramics/alumina composites sintered at 875 °C, but the relative amounts of the phases varied greatly with different glass-ceramic compositions and were considered to be determined by the ratio of La2O3 to B2O3. The onset sintering temperatures of green composites were ~ 670 °C and the sintering shrinkage of the samples was mainly determined by the low-softening glass-ceramics. Optimum properties were exhibited for the composite of 25 La2O3-65 B2O3-10 Al2O3 glass-ceramic with 40 wt% Al2O3 sintered at 900 °C with a permittivity εr = 7.91, a dielectric loss tan δ = 2.12 × 10−3 (at 8.1 GHz). The low εr and tan δ coupled with a low sintering temperature, suggested that the LBA glass-ceramic/Al2O3 composites were potential candidates for LTCC applications. [ABSTRACT FROM AUTHOR]

Randomness is important for many information processing applications, including numerical modelling and cryptography1,2. Device-independent quantum random-number generation (DIQRNG)3,4 based on the loophole-free violation of a Bell inequality produces genuine, unpredictable randomness without requiring any assumptions about the inner workings of the devices, and is therefore an ultimate goal in the field of quantum information science5-7. Previously reported experimental demonstrations of DIQRNG8,9 were not provably secure against the most general adversaries or did not close the ‘locality’ loophole of the Bell test. Here we present DIQRNG that is secure against quantum and classical adversaries10-12. We use state-of-the-art quantum optical technology to create, modulate and detect entangled photon pairs, achieving an efficiency of more than 78 per cent from creation to detection at a distance of about 200 metres that greatly exceeds the threshold for closing the ‘detection’ loophole of the Bell test. By independently and randomly choosing the base settings for measuring the entangled photon pairs and by ensuring space-like separation between the measurement events, we also satisfy the no-signalling condition and close the ‘locality’ loophole of the Bell test, thus enabling the realization of the loophole-free violation of a Bell inequality. This, along with a high-voltage, high-repetition-rate Pockels cell modulation set-up, allows us to accumulate sufficient data in the experimental time to extract genuine quantum randomness that is secure against the most general adversaries. By applying a large (137.90 gigabits × 62.469 megabits) Toeplitz-matrix hashing technique, we obtain 6.2469 × 107 quantum-certified random bits in 96 hours with a total failure probability (of producing a random number that is not guaranteed to be perfectly secure) of less than 10−5. Our demonstration is a crucial step towards transforming DIQRNG from a concept to a key aspect of practical applications that require high levels of security and thus genuine randomness7. Our work may also help to improve our understanding of the origin of randomness from a fundamental perspective. Genuine, unpredictable quantum random-number generation that is provably secure against quantum and classical adversaries is demonstrated, certified by the loophole-free violation of a Bell inequality. [ABSTRACT FROM AUTHOR]

Nitrogen-containing organic compounds (NOC) formed from secondary organic aerosols (SOA) age via reaction with reduced nitrogen species are a vital class of brown carbon compounds. NOC compounds from ammonia (NH3) gas-aging of benzene SOA were investigated in present study, and the experiments were performed by irradiating benzene/CH3ONO/NO/NH3 air mixtures in a home-made smog chamber. The particulate NOC products of aged benzene SOA in the presence of NH3 were measured by UV-Vis spectrophotometer, attenuated total reflectance-Fourier transform infrared (ATR-FTIR), and aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with Fuzzy C-Means (FCM) clustering algorithm, respectively. Experimental results demonstrated that NH3 has significant promotion effect on benzene SOA formation. Organic ammonium salts, such as ammonium glyoxylate, ammonium 6-oxo-2,4-hexadienoiclate, which are formed from NH3 reactions with gaseous organic acids were detected as the major particulate NOC products of NH3-aged benzene SOA. 1H-imidazole, 1H-imidazole-2-carbaldehyde and other imidazole products via the heterogeneous reactions between NH3 and dialdehydes of benzene SOA were successfully detected as important brown carbon constituents. The formation of imidazole products suggests that some ambient particles contained organonitrogen compounds may be come from this mechanism. The results of this study may provide valuable information for discussing NH3 deposition and SOA aging mechanisms. [ABSTRACT FROM AUTHOR]

Glass + ceramic composites based on low-softening-point borosilicate (BS) glass, β-spodumene and Al2O3 were produced in this work. The influence of ceramic filler composition on the microstructure, sintering quality, mechanical properties, thermal properties and dielectric properties of composites were studied. XRD and DSC indicated that both kinds of ceramic filler as well as the BS glass maintained their characteristics after sintering. The addition of β-spodumene would decrease the coefficient of thermal expansion (CTE) value of composites to match with silicon well. The better wetting behavior between β-spodumene and BS glass would lead to better sintering quality, microstructure and dielectric properties for composites containing more β-spodumene. With appropriate Al2O3 content, the flexural strength of composites could be enhanced. Composite with 45 wt% BS glass, 30 wt% β-spodumene and 25 wt% Al2O3 sintered at 875 °C showed good properties which meet the requirements of low temperature co-fired ceramic applications: dense microstructure with high relative density of 96.27%, proper CTE value of 3.57 ppm/°C, high flexural strength of 156 MPa, low dielectric constant of 6.20 and low dielectric loss of 1.9 × 10−3. [ABSTRACT FROM AUTHOR]

The rapid development of superconducting nanowire single-photon detectors over the past decade has led to numerous advances in quantum information technology. The record for the best system detection efficiency at an incident photon wavelength of 1550 nm is 93%. This performance was attained from a superconducting nanowire single-photon detector made of amorphous WSi; such detectors are usually operated at sub-Kelvin temperatures. In this study, we first demonstrate superconducting nanowire single-photon detectors made of polycrystalline NbN with system detection efficiency of 90.2% for 1550-nm-wavelength photons at 2.1 K, accessible with a compact cryocooler. The system detection efficiency saturated at 92.1% when the temperature was lowered to 1.8 K. We expect the results lighten the practical and high performance superconducting nanowire single-photon detectors to quantum information and other high-end applications. [ABSTRACT FROM AUTHOR]

The binding motif of BF2*15 major histocompatibility complex (MHC) class I was explored by analyzing the interaction between an infectious bronchitis virus octapeptide and BF2*15, and the cytotoxic T lymphocyte (CTL) epitope from the nucleoprotein (NP) of H5N1 virus was identified using experimental methods. Computational methods, including homology modeling, molecular dynamics simulation, and molecular docking analysis, were used. The recombinant plasmid pCAGGS-NP was constructed, and NP expression was confirmed by indirect immunofluorescence and Western blot in transfected 293T cells. Antibodies against NP in pCAGGS-NP-inoculated specific-pathogen-free chickens were detected by enzyme-linked immunosorbent assay (ELISA). Interferon γ (IFN-γ) mRNA was quantified, and IFN-γ production was evaluated using quantitative reverse transcription PCR and capture ELISA, respectively. CD8 T-lymphocyte proliferation was detected using flow cytometric analysis. The BF2*15 MHC class I binding motif 'x-Arg/Lys-x-x-x-Arg/Lys' was explored. Quantification of chicken IFN-γ mRNA, evaluation of IFN-γ production, and measurement of CD8 T-lymphocyte proliferation confirmed that the peptide NP of H5N1 was the BF2*15 MHC-class-I-restricted CTL epitope. [ABSTRACT FROM AUTHOR]

Inorganic seed particles have relatively large surface area, and play an important role in the formation and aging of secondary organic aerosol (SOA). The effects of dry (NH)SO which is the most commonly found in urban atmosphere on the aged benzene SOA were qualitatively studied utilizing aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with Fuzzy C-Means (FCM) clustering algorithm in this study. Experimental results indicated that nitrophenol, oxocarboxylic acid, epoxide products are the predominant components in the aged benzene SOA in the presence of low concentration (about 10 μg m) of dry (NH)SO. These aged products are the same as the previously obtained aged benzene SOA without (NH)SO seed aerosol, indicating that low concentration of dry (NH)SO acts just as the nucleation or condensation center of the SOA, and do not affect the chemical composition of SOA. However, 1 H-imidazole, 1 H-imidazole-2-carbaldehyde, hydrated 1 H-imidazole-2-carbaldehyde, 2,2′-biimidazole, hydrated N-glyoxal substituted 1 H-imidazole, N-glyoxal substituted hydrated 1 H-imidazole-2- carbaldehyde, hydrated mono glyoxal substituted hydrated 1 H-imidazole-2-carboxaldehyde, mono glyoxal substituted 2,2-biimidazole and hydrated glyoxal dimer substituted imidazole which are formed from ammonium ion reaction with glyoxal are the major particulate products in the aged benzene SOA in the presence of high concentration (about 100 μg m) of dry (NH)SO. The retention of water on the dry (NH)SO particles creates ammonium ion, which can promote the formation of high-molecular-weight (HMW) products through multiphase reactions such as hydration and polymerization of aldehydes form from OH-initiated oxidation of benzene. [ABSTRACT FROM AUTHOR]

CaCuTiO (CCTO) powders derived from sol-gel precursors were calcined and sintered via microwave radiation. The obtained CCTO powders were compared with that obtained via a conventional heating method. For microwave heating, 89.1 wt.% CCTO was achieved from the sol-gel precursor, after only 17 min at 950°C. In contrast, the conventional calcination method required 3 h to generate 87.6 wt.% CCTO content at 1100°C. In addition, the CCTO powders prepared through 17 min of microwave calcination exhibited a small particle size distribution of D = 3.826 μm. It was found that a lengthy hold time of 1 h by microwave sintering is required to obtain a high dielectric constant (3.14 × 10 at 10 Hz) and a reasonably low dielectric loss (0.161) in the sintered CCTO ceramic. Based upon the distinct microstructures, the dielectric responses of the CCTO samples sintered by different methods are attributed to space charge polarization and internal barrier layer capacitor mechanism. [ABSTRACT FROM AUTHOR]

Trace-gas sensors have a wide range of potential applications such as environmental monitoring, climate research, agriculture, workplace safety, medical diagnostics, and industrial process control. A recently introduced technique called quartz-enhanced photoacoustic spectroscopy (QEPAS) is described. QEPAS use a quartz tuning fork as an acoustic transducer for a photoacoustic signal induced in an absorbing gas by modulated optical radiation. Advantages of the QEPAS compared to conventional photoacoustic spectroscopy include immunity to environmental acoustic noise and ultra-small sample volume. Trace gases of $$\hbox {CH}_{4}, \hbox {H}_{2}\hbox {O}$$ , and $$\hbox {NO}_{2}$$ were monitored with a novel off-beam QEPAS approach and are described in detail. [ABSTRACT FROM AUTHOR]

Secondary organic aerosol (SOA) from the photooxidation of aromatic compounds is a very complex mixture containing products with a different chemical nature that are dependent on aging processes. Aging of SOA particles formed from OH-initiated oxidation of benzene was investigated in a home-made smog chamber in this study. The chemical composition of aged benzene SOA particles were measured using aerosol laser time-of-flight mass spectrometer (ALTOFMS) coupled with Fuzzy C-Means (FCM) clustering algorithm. Experimental results showed that nitrophenol, dinitrophenol, nitrocatechol, dinitrocatechol, 6-oxo-2,4-hexadienoic acid, 2,4-hexadiendioic acid, 2,3-dihydroxy-6-oxo-4-hexenoic acid, 2,3-epoxy-4-hexendioic acid, 2,3-epoxy-4,5-dihydroxy-hexanedioic acid and high-molecular-weight (HMW) components were the predominant products in the aged particles. Compared to offline method such as liquid chromatography mass spectrometry (LC-MS) measurement, the real-time ALTOFMS detection approach coupled with the FCM data processing algorithm can make cluster analysis of SOA successfully and provide more information of products. The present results also indicate that benzene SOA aging proceeds through the oxidation of the internal double bond of ring-opened products, phenolic compounds, and acid-catalyzed heterogeneous reactions of carbonyl products. The possible reaction mechanisms leading to these aged products were also discussed and proposed. [ABSTRACT FROM AUTHOR]