Propagation of Coupled Acoustic, Electromagnetic and Spin Waves in Saturated Ferromagnetoelastic Solids

We study the propagation of plane waves in an unbounded body of a saturated ferromagnetoelastic solid. The equations by Tiersten for small fields superposed on finite initial fields in a saturated ferromagnetoelastic material are employed, with their quasistatic magnetic field extended to dynamic electric and magnetic fields for electromagnetic waves. Dispersion relations of the plane waves are obtained. The cutoff frequencies and long wave approximation of the dispersion curves are determined. Results show that acoustic, electromagnetic and magnetic spin waves are coupled in such a material. For YIG which is a cubic crystal without piezoelectric coupling, the acoustic and electromagnetic waves are not directly coupled but they can still interact indirectly through spin waves

Multiple abiotic and biotic drivers of long-term wood decomposition within and among species in the semi-arid inland dunes:A dual role for stem diameter

Litter decomposition in sunny, semi-arid and arid ecosystems is controlled by both biotic factors including litter traits and abiotic factors including UV light, but for wood decomposition it still remains uncertain which of these environmental factors are the predominant controls among different woody species. In these dry ecosystems, it is likely that the stem diameter and spatial position of the dead wood are of particular importance especially where wood can be buried versus exposed due to substrate displacement by wind. Here we focus on the fact that stem diameter can affect decomposition rates both via the relative surface exposure to sunlight or soil and via higher resource quality of narrower stems to decomposers. In a field manipulation experiment, we investigated the relative importance of litter position (sand burial vs. surface vs. suspended above the surface), UV radiation (block versus pass) and stem diameter class (<2, 2–4, 4–8, 8–13 and 13–20 mm) on the mass loss of woody litters of four shrub species in an inland dune ecosystem in northern China. We found that after 34 months of in situ incubation, the mass loss of buried woody litters was three times faster than those of suspended and surface woody litters (53.5 ± 2.7%, 17.0 ± 1.0% and 14.4 ± 1.2%, respectively). In surface and suspended positions, litter decomposition rates were almost equally low and most mass loss was during the first 2 years, when bark was still attached and UV radiation had no significant effect on woody litter mass loss. These findings suggest that sand burial is the main environmental driver of wood decomposition via its control on microbial activity. Moreover, wood N and diameter class were the predominant factors driving woody litter decomposition. A key finding was that wider stems had slower litter decomposition rates not only directly (presumably via greater relative surface exposure) but also indirectly via their higher wood dry matter content or lower wood N; these effects were modulated by litter position. Our findings highlight a dual role of stem diameter on wood decomposition, that is, via relative surface exposure and via wood traits. The accuracy and confidence of global carbon cycling models would be improved by incorporating the different effects of stem diameter on woody litter decomposition and below-ground wood decomposition processes in drylands

Baicalin Attenuates Oxygen–Glucose Deprivation/Reoxygenation–Induced Injury by Modulating the BDNF-TrkB/PI3K/Akt and MAPK/Erk1/2 Signaling Axes in Neuron–Astrocyte Cocultures

Background: Baicalin (BCL), a candidate drug for ischemic stroke, has been indicated to protect neurons by promoting brain-derived neurotrophic factor (BDNF). However, the cellular source of BDNF release promoted by baicalin and its detailed protective mechanism after ischemia/reperfusion remains to be studied. The aim of this study was to investigate the neuroprotective mechanisms of baicalin against oxygen–glucose deprivation/reoxygenation (OGD/R) in a neuron–astrocyte coculture system and to explore whether the BDNF-TrkB pathway is involved.Methods and Results: A neuron–astrocyte coculture system was established to elucidate the role of astrocytes in neurons under OGD/R conditions. The results demonstrated that astrocytes became reactive astrocytes and released more BDNF in the coculture system to attenuate neuronal apoptosis and injury after OGD/R. BCL maintained the characteristics of reactive astrocytes and obviously increased the expression of cyclic AMP response element-binding protein (CREB) and the levels of BDNF in the coculture system after OGD/R. To further verify whether BDNF binding to its receptor tyrosine kinase receptor B (TrkB) was required for the neuroprotective effect of baicalin, we examined the effect of ANA-12, an antagonist of TrkB, on NA system injury, including oxidative stress, inflammation, and apoptosis induced by OGD/R. The results showed that treatment of NA systems with ANA-12 significantly attenuated the neuroprotection of BCL. The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathways are two important downstream cascades of signaling pathways activated by BDNF binding to TrkB. We investigated the expressions of TrkB, PI3K, Akt, MAPK, and ERK. The results demonstrated that baicalin significantly increased the expressions of TrkB, PI3K/AKT, and MAPK/ERK.Conclusion: The neuroprotective effects of baicalin against oxidative stress, inflammation, and apoptosis were improved by astrocytes, mainly mediated by increasing the release of BDNF and its associated receptor TrkB and downstream signaling regulators PI3K/Akt and MAPK/ERK1/2

Spatial Patterns and Drivers of Microbial Taxa in a Karst Broadleaf Forest

Spatial patterns and drivers of soil microbial communities have not yet been well documented. Here, we used geostatistical modeling and Illumina sequencing of 16S rRNA genes to explore how the main microbial taxa at the phyla level are spatially distributed in a 25-ha karst broadleaf forest in southwest China. Proteobacteria, dominated by Alpha- and Deltaproteobacteria, was the most abundant phylum (34.51%) in the karst forest soils. Other dominating phyla were Actinobacteria (30.73%), and Acidobacteria (12.24%). Soil microbial taxa showed spatial dependence with an autocorrelation range of 44.4–883.0 m, most of them within the scope of the study plots (500 m). An increasing trend was observed for Alphaproteobacteria, Deltaproteobacteria, and Chloroflexi from north to south in the study area, but an opposite trend for Actinobacteria, Acidobacteira, and Firmicutes was observed. Thaumarchaeota, Bacteroidetes, Gemmatimonadetes, and Verrucomicrobia had patchy patterns, Nitrospirae had a unimodal pattern, and Latescibacteria had an intermittent pattern with low and high value strips. Location, soil total phosphorus, elevation, and plant density were significantly correlated with main soil bacterial taxa in the karst forest. Moreover, the total variation in soil microbial communities better explained by spatial factors than environmental variables. Furthermore, a large part of variation (76.8%) was unexplained in the study. Therefore, our results suggested that dispersal limitation was the primary driver of spatial pattern of soil microbial taxa in broadleaved forest in karst areas, and other environmental variables (i.e., soil porosity and temperature) should be taken into consideration

An integrated genomic and expression analysis of 7q deletion in splenic marginal zone lymphoma.

Splenic marginal zone lymphoma (SMZL) is an indolent B-cell lymphoproliferative disorder characterised by 7q32 deletion, but the target genes of this deletion remain unknown. In order to elucidate the genetic target of this deletion, we performed an integrative analysis of the genetic, epigenetic, transcriptomic and miRNomic data. High resolution array comparative genomic hybridization of 56 cases of SMZL delineated a minimally deleted region (2.8 Mb) at 7q32, but showed no evidence of any cryptic homozygous deletion or recurrent breakpoint in this region. Integrated transcriptomic analysis confirmed significant under-expression of a number of genes in this region in cases of SMZL with deletion, several of which showed hypermethylation. In addition, a cluster of 8 miRNA in this region showed under-expression in cases with the deletion, and three (miR-182/96/183) were also significantly under-expressed (P<0.05) in SMZL relative to other lymphomas. Genomic sequencing of these miRNA and IRF5, a strong candidate gene, did not show any evidence of somatic mutation in SMZL. These observations provide valuable guidance for further characterisation of 7q deletion

Effects of air pollution on neonatal prematurity in guangzhou of china: a time-series study

<p>Abstract</p> <p>Background</p> <p>Over the last decade, a few studies have investigated the possible adverse effects of ambient air pollution on preterm birth. However, the correlation between them still remains unclear, due to insufficient evidences.</p> <p>Methods</p> <p>The correlation between air pollution and preterm birth in Guangzhou city was examined by using the Generalized Additive Model (GAM) extended Poisson regression model in which we controlled the confounding factors such as meteorological factors, time trends, weather and day of the week (DOW). We also adjusted the co linearity of air pollutants by using Principal Component Analysis. The meteorological data and air pollution data were obtained from the Meteorological Bureau and the Environmental Monitoring Centre, while the medical records of newborns were collected from the perinatal health database of all obstetric institutions in Guangzhou, China in 2007.</p> <p>Results</p> <p>In 2007, the average daily concentrations of NO₂, PM₁₀and SO₂in Guangzhou, were 61.04, 82.51 and 51.67 μg/m³respectively, where each day an average of 21.47 preterm babies were delivered. Pearson correlation analysis suggested a negative correlation between the concentrations of NO₂, PM₁₀, SO_2,and temperature as well as relative humidity. As for the time-series GAM analysis, the results of single air pollutant model suggested that the cumulative effects of NO₂, PM₁₀and SO₂reached its peak on day 3, day 4 and day 3 respectively. An increase of 100 μg/m³of air pollutants corresponded to relative risks (RRs) of 1.0542 (95%CI: 1.0080 ~1.1003), 1.0688 (95%CI: 1.0074 ~1.1301) and 1.1298 (95%CI: 1.0480 ~1.2116) respectively. After adjusting co linearity by using the Principal Component Analysis, the GAM model of the three air pollutants suggested that an increase of 100 μg/m³of air pollutants corresponded to RRs of 1.0185 (95%CI: 1.0056~1.0313), 1.0215 (95%CI: 1.0066 ~1.0365) and 1.0326 (95%CI: 1.0101 ~1.0552) on day 0; and RRs of the three air pollutants, at their strongest cumulative effects, were 1.0219 (95%CI: 1.0053~1.0386), 1.0274 (95%CI: 1.0066~1.0482) and 1.0388 (95%CI: 1.0096 ~1.0681) respectively.</p> <p>Conclusions</p> <p>This study indicates that the daily concentrations of air pollutants such as NO₂, PM₁₀and SO₂have a positive correlation with the preterm births in Guangzhou, China.</p

Light management in nanostructures for solar cell application

Solar cells have received great interest and tremendous efforts have been devoted in the last few decades. However, the main problem of the conventional solar cell is that the cost is too high to achieve relatively high efficiency. In order to make the solar cell affordable to public, scientists are now focusing on the design of the third generation solar cells named as nanostructured solar cell. By texturing the front, back surface or the active layer itself, the light absorption and thus the efficiency can be largely improved. The other way to improve the light absorption is to directly texture the active layer into nanostructures which is also promising to achieve high efficiency and low cost solar cells. Transparent electrodes are essential part of the solar cell device. Indium tin oxides (ITOs) are the most widely used transparent electrodes for solar cell nowadays. However, the price of indium mineral has soared to rocket high due to the huge demand and limited mineral reserves. Thus, scientists are now trying to seek for alternative materials to replace ITO electrodes. The work of this thesis mainly focuses on the design and investigation of three types of nanostructures: anti-reflective coating, metallic nanostructure electrodes and nanostructured active layer. Nanostructured anti-reflective coatings achieved by front surface texturing have been studied intensively. Zinc Oxide (ZnO) nanowire and nanohole structures are presented in this work. The designed nanostructures can act as an anti-reflective coating in the visible range and also serves as a UV blocking layer simultaneously. The important structure parameters such as period and filling ratio are varied and optimized to achieve high transmittance in the visible range and high absorptance in the UV range. The optical properties of nanowire and nanohole structures, as well as the angular response properties are investigated in detail. A nanopatterned aluminum thin film electrode is also presented. With the optimized parameters, the nanopatterned aluminum thin film exhibits a high transmittance in the range from 300 – 1000 nm and has a low sheet resistance, which makes it a potential electrode to replace ITO. In this work, the key parameters such as period and filling ratio are optimized to increase transmittance and in the meantime reduce sheet resistance. The optical properties are analyzed in detail and the role of surface plasma polariton (SPP) in the influence of transmission spectrum is particularly discussed. Hole filling materials, substrate materials and angular response are also taken into consideration in the nanopatterned aluminum electrode design. Several commonly used metals are optimized respectively aiming to obtain high performance nanostructured metallic electrodes. In order to further increase the absorption in the active layer, a new type of nano-cone-hole (NCH) array was brought into study. With the optimized NCH array, the absorptance is largely enchanced compared to the thin film and the optimized nanohole (NH) array. The absorptance enhancement is attributed to the lower surface reflectance; more supported resonant modes and enhanced modes interaction. The angular dependences of ultimate efficiency of transverse electric (TE) and transverse magnetic (TM) polarizations are also studied. The influence on absorptance by introducing randomness into nanowire (NW) arrays is also investigated. The absorptance in the active layer can be improved by randomizing the regular arranged NW array. The ultimate efficiency of the optimized position random case is improved by 15% as compared to the regularly arranged one. According to electric field distribution at two different wavelengths, the absorption enhancement of random structure is due to a better anti-reflective performance, additional resonances introduced by the structural disorder and existing resonances broadening. In summary, this dissertation addresses three types of nanostructure designs, including the nanostructured ZnO anti-reflective coating, the nanopatterned metallic electrode and the nanostructured active layer. The work done here will help to understand better the design rules for light management in nanostructures and the know-how can be applied to new type nanostructure design for solar cells.DOCTOR OF PHILOSOPHY (EEE

Study on the adsorption characteristics of aqueous caffeine solutions on macroporous resins with hydrogen-bonding interactions

531-538The adsorption characteristics of caffeine on six macroporous resins have been investigated. The results show that the resin with hydroxyl groups (XDA-200) offer better adsorption/ desorption capacity than other resins, and its adsorption kinetics fit a pseudo- second-order model. The adsorption process is a type of fast adsorption, and multiple adsorption mechanisms controlled the rate of adsorption. The isothermal equilibrium curve of caffeine adsorbed onto XDA-200 show a good fit to the Freundlich model, and thermodynamics tests show that the process is exothermic and spontaneous. The absolute value of enthalpy is 14.347 kJ/mol, which is in the range of the adsorption enthalpy related to hydrogen-bonding interactions. XPS and FTIR analyses also verify the existence of hydrogen-bonding interactions

Study on the adsorption characteristics of aqueous caffeine solutions on macroporous resins with hydrogen-bonding interactions

The adsorption characteristics of caffeine on six macroporous resins have been investigated. The results show that the resin with hydroxyl groups (XDA-200) offer better adsorption/ desorption capacity than other resins, and its adsorption kinetics fit a pseudo- second-order model. The adsorption process is a type of fast adsorption, and multiple adsorption mechanisms controlled the rate of adsorption. The isothermal equilibrium curve of caffeine adsorbed onto XDA-200 show a good fit to the Freundlich model, and thermodynamics tests show that the process is exothermic and spontaneous. The absolute value of enthalpy is 14.347 kJ/mol, which is in the range of the adsorption enthalpy related to hydrogen-bonding interactions. XPS and FTIR analyses also verify the existence of hydrogen-bonding interactions

Transformation and products of captopril with humic constituents during laccase-catalyzed oxidation: Role of reactive intermediates

The transformation of captopril (CAP), a widely-used thiol drug, was studied with the presence of dissolved model humic constituents (HCs) in a laccase-catalyzed system. Reaction products were analyzed by ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry and condensed fukui function computation. CAP reacted with different model HCs in the enzymatic system for 1 h, ranging from 75% (syringic acid) to 96% (p-coumaric acid). In the absence of HCs, only 15% of CAP was removed through self-coupling. The presence of HCs apparently changed the transformation of CAP in aqueous environment, and the HC reactive intermediates played an important role. First, during laccase catalysis, HCs with different structures were oxidized to produce reactive intermediates, including phenoxyl radical cation, ortho-, and pars-quinone intermediates. Second, these intermediates were readily attacked by CAP via nucleophilic reactions, forming C-S-C covalent conjugates. More importantly, the standard reduction potential of these intermediates is a critical parameter, as PCA showed the highest reactivity to the nucleophilic addition reaction with CAP by forming phenoxy radical cations. While SYR showed the least reactivity due to the formation of pars-quinone intermediates. Therefore, the functional groups on HCs could greatly influence the cross-coupling with CAP, as well as the type and stability of the coupling products. This work clearly demonstrated the transformation of CAP and other thiol drugs with the presence of HCs in aqueous environment, which is similar to the natural humification process. (C) 2016 Elsevier Ltd. All rights reserved.</p