Sodium current of neurosecretory cells in the eyestalk from the shrimp Penaeus japonicus

The properties of the inward current of medulla terminalis-X-organ (MTXO) cells isolated from the Penaeus japonicus eyestalk were studied with the whole-cell clamp technique in the presence of Ca²⁺ and K⁺ channel blockers. The inward currents had a threshold at about −50 mV and peaked at −10 mV. The reversed potential (V_rev) was very close to V_Na, the theoretical Nernst equilibrium potential for Na⁺. V_rev followed V_Na when the external Na⁺ concentration was varied and the currents were entirely suppressed by 30 nM tetrodotoxin (TTX), indicating that it was carried by Na⁺. The smooth line of concentration-dependent inhibition of sodium currents by TTX represented the best fit with the Hill equation, yielding an IC₅₀ of 2.1 ± 0.1 nM. The values of the half-maximal activation voltage V_h were −20.6 ± 0.5 and −19.3 ± 0.5 mV, respectively, in the absence and presence of 2 nM TTX. TTX had no significant effect on the voltage dependence of steady-state activation and inactivation of I_Na. Taken together, the results suggest that the inward current recorded under our experimental conditions was carried by sodium ions flowing through fast voltage-dependent Na⁺ channels.     

Short-term dynamics of nutrients influenced by upwelling in a small oligotrophic coastal ecosystem, Gan Bay, in the northwest Philippines

We present a time-series analysis of nutrient and pCO2 (partial pressure of CO2) levels in an oligotrophic coastal ecosystem (Gan Bay), which was likely to be influenced by upwelled subsurface water. Gan Bay is off Currimao Harbor, in the northwest Philippines and is located at the boundary of the South China Sea (SCS). This 42-h time-series observation was conducted in December 2006. In addition to continuous observations of dissolved oxygen (DO) and pCO2, discrete samples were collected at a depth of 5 m every 3 h for measurements of nutrients, including soluble reactive phosphorus (SRP) and inorganic nitrogen (NO3 +NO2 ) in order to examine their dynamics and possible physical and biological controls. We observed remarkably large short-term variations in the surface water,spanning a 10-fold change for SRP (32–330 nM) and from <0.3 μM to 4.3 μM for NO3 +NO2 . DO also varied substantially from a lower end of 171 to 205 μM O2. Surface water pCO2 changed from an equilibrium stage with the atmosphere ( 386 μatm) to a stage where it was a significant source for the atmospheric CO2 (seawater pCO2 469 μatm). We found that the variation of nutrients was driven neither by tidal mixing nor by biological activities, as was suggested by the variations in the total bacterial abundance and chlorophyll a. Instead, our inverse T–S relationship suggested a two end-member mixing process during the observation period. The N:P ratio throughout the observation period was 13.2, which is characteristic of SCS subsurface and deep waters. Moreover, pCO2 was correlated inversely with the sea surface temperature. It is likely, therefore, that an upwelled subsurface cold water with high nutrients, low-temperature and high-pCO2 existed. It should be noted that this upwelled cold water did not appear to impact the entire observation period (approximately 35 h of 42 h), which might suggest an extremely dynamic nature for this upwelled cold water mass.     

Mechanical properties of directionally solidified lead-antimony alloys

The Pb-17wt% Sb alloy was directionally solidified under two solidification conditions: with different temperature gradients (G=0.93–3.67 K/mm) at a constant growth rate (V=17.50 μm/s) and with different growth rates (V=8.3–497 μm/s) at a constant temperature gradient (G=3.67 K/mm) in a Bridgman furnace. Microstructure parameters, such as primary dendrite arm spacing (λ₁), secondary dendrite arm spacing (λ₂), and dendrite tip radius (R), were measured. The microhardness (Hv) and ultimate tensile strength (σ) of the directional solidification samples were also measured. The influences of solidification and microstructure parameters on Hv and σ were investigated. The results obtained in this work were compared with similar experimental researches in literatures. It is shown that the Hv and σ values increase with the increase of G and V, but decrease with the increase of λ₁, λ₂, and R.     

Evolution of several soil properties following amendment with olive mill wastewater

Occurrences of olive mill wastewater (OMW) amendment on several chemical and biochemical properties of soil were investigated. Compared to the control, soils amended with untreated and treated OMW (by an integrated process based on aerobic fungal pre-treatment using Phanerochaete chrysosporium DSMZ 6909 followed by anaerobic treatment) showed high levels of organic and mineral matters. Soil amended with untreated OMW presented low levels of total and inorganic nitrogen (0.38 and 0.08 mg g⁻¹ dry soil). Treated OMW contained little content of pollutants (COD = 4 g l⁻¹; phenolic compounds = 0.6 g l⁻¹); so, organic matter brought by these residues was rapidly mineralized in the soil. The number of heterotrophic bacteria was increased (from 54 × 10⁵ CFU g⁻¹ dry soil in control soil to 123 × 10⁵ CFU g⁻¹ dry soil) in response to the OMW amendment, mainly after C/N ratio correction. Untreated OMW application improved the soil carbon content (2.18 times higher), while the specific respiration remained very low. However, the treated OMW application positively affected the soil-specific respiration that increased from 6.1 in control soil to 9.75 in soil amended with treated OMW. This phenomenon was accompanied by an enhancement of nitrifiers number, urease and ammonium oxidases activities.     

High-pressure sound velocity of perovskite-enstatite and the possible composition of the Earth’s lower mantle

The compressional sound velocity V_p for enstatite of polycrystalline specimens were measured at pressures from 40 to 140 GPa using the optical analytical techniques under shock loading. The dependence of V_P, (in km/s) on Hugoniot pressure (P, in GPa) can be described by InV_p= 3.079-0.691 In(P) + 0.094(lnP)². V_p satisfies Birch’s law:V _p = 4.068 + 1.677_ρ, where ρ is corresponding density, which indicated that enstatite is stable throughout the conditions of the lower mantle. The wave velocityP is 0.5% lower and the wave velocity S is 2% higher than that of PREM respectively. We concluded that the lower mantle is mainly composed of perovskite-(Mg_1-x, Fe_x) SiO₃ and only a small amount of (Mg_1-x, Fe_x) O is allowed in it.     

Mechanical,electrical, and thermal properties of the directionally solidified Bi-Zn-Al ternary eutectic alloy

A Bi-2.0Zn-0.2Al (wt%) ternary eutectic alloy was prepared using a vacuum melting furnace and a casting furnace. The samples were directionally solidified upwards at a constant growth rate (V = 18.4 μm/s) under different temperature gradients (G = 1.15–3.44 K/mm) and at a constant temperature gradient (G = 2.66 K/mm) under different growth rates (V = 8.3–500 μm/s) in a Bridgman-type directional solidification furnace. The dependence of microstructure parameter (λ) on the solidification parameters (G and V) and that of the microhardness (Hv) on the microstructure and solidification parameters were investigated. The resistivity (ρ) measurements of the studied alloy were performed using the standard four-point-probe method, and the temperature coefficient of resistivity (α) was calculated from the ρ-T curve. The enthalpy (ΔH) and the specific heat (C_p) values were determined by differential scanning calorimetry analysis. In addition, the thermal conductivities of samples, obtained using the Wiedemann-Franz and Smith-Palmer equations, were compared with the experimental results. The results revealed that, the thermal conductivity values obtained using the Wiedemann-Franz and Smith-Palmer equations for the Bi-2.0Zn-0.2Al (wt%) alloy are in the range of 5.2–6.5 W/Km and 15.2–16.4 W/Km, respectively.     

Chenguodaite （Ag9FeTe2S4）： a new tellurosulfide mineral from the gold district of East Shandong Peninsula,China

Chenguodaite, approved by IMA-CNMMN （2004-042a）, was discovered in the Bunan quartz vein-type gold deposit in the gold district of East Shandong Peninsula. The mineral occurs in high grade Au-Ag-Cu ores, coexisting with galena, chalcopyrite, hessite, electrum, unnamed Ag6TeS2 and AglsFeBiTe3Se, enclosed and replaced by native silver and acanthite. In the reflected light microscope, the mineral has light gray color, indistinguishable anistropism and hardness around 2-3. The color indices of chenguodaite relative to ICE C illuminator are： x=0.3027, y=0.3076, Y=25.78%,λd=474 nm, Pe=3.68%, similar to those of canfieldite. The average chemical composition from 16 microprobe analyses is Ag8.97Fe1.00Te1.99S4.04, idealized to AggFeTe2S4. The polycrystalline X-ray diffraction of chenguodaite by Gandolfi camera and synchrotron oscillation photography results in 67 reflections with the 12 strongest being （relative intensity in bracket）： 6.742（69）, 6.416（39）, 5.951（33）, 3.265（100）, 2.981（24）, 2.649（22）, 2.25（24）, 2.188（71）, 2.142（22）, 2.123（31）, 2.044（23）, 1.949（33）, which are indexed to a primitive orthorhombic cell with a=12.769 （2） A, b= 14.814（2） A, c= 16.233 （1） A, V= 3070.6 A^3, Z= 9, Dcal.=6.85 g/cm^3. The name is for the late Prof. Chen Guoda, a famous Chinese geologist and the founder of Diwa-Geodepression theory of tectonics.     

The Earth's mantle

Seismological images of the Earth's mantle reveal three distinct changes in velocity structure, at depths of 410, 660 and 2,700 km. The first two are best explained by mineral phase transformations, whereas the third-the D" layer-probably reflects a change in chemical composition and thermal structure. Tomographic images of cold slabs in the lower mantle, the displacements of the 410-km and 660-km discontinuities around subduction zones, and the occurrence of small-scale heterogeneities in the lower mantle all indicate that subducted material penetrates the deep mantle, implying whole-mantle convection. In contrast, geochemical analyses of the basaltic products of mantle melting are frequently used to infer that mantle convection is layered, with the deeper mantle largely isolated from the upper mantle. We show that geochemical, seismological and heat-flow data are all consistent with whole-mantle convection provided that the observed heterogeneities are remnants of recycled oceanic and continental crust that make up about 16 and 0.3 per cent, respectively, of mantle volume.     

Average widths and optimal recovery of multivariate Besov classes inL p (Rd)

Some weak asymptotic results for average σ-K width and average σ_L width of the isotropic Besov classes S r pθB(R d), S r pθb(R d) and the anisotropic Besov classes S r pθB(R d), S r pθb(R d) in L p(R d) (1≤p<∞) are obtained, and the corresponding weak asymptotic optimal subspaces are identified. Furthermore, the weak asymptotic behavior of optimal recovery is established for the isotropic Besov classes S r pθB(R d) in L p(R d) (1≤p≤∞).     

Preparation by a rheological phase reaction method and thermal decomposition reaction mechanism of nickelous salicylate tetrahydrate

0　IntroductionInrecentyears,studiesonBinghamfluid ,suchasElec trorheologicalfluid ,areactivelypursued[1 6] .Rheologicaltechniqueshavebeenplayinganimportantroleinsyntheticchem istry .Therheologicalphasereactionmethodisthe processofpreparingcompoundsormaterialsfromasolid liquidrheologicalmixture.Thatis,thesolidreactantsarefullymixedinapropermolarratio ,andmadeupbyaproperamountofwaterorothersolventstoaBinghambodyinwhichthesolidparticlesandliquidsubstanceareuniformlydistributed ,sothattheprodu…     

Comparative crystal structure determination of griseofulvin: Powder X-ray diffraction versus single-crystal X-ray diffraction

In an attempt to compare crystal structure determination from powder data and single-crystal data,crystal structure of griseofulvin(C 17 H 17 ClO 6) was tested by both powder and single-crystal X-ray diffraction.Lattice parameters of griseofulvin are α=90.0°,a=b=8.9757,c=19.9345,V=1605.99 3 from powder data coinciding with α=90.0°,a=b=8.9714,c=19.8848,V=1600.46 3 from single-crystal data.Main processes of structure elucidating of griseofulvin by the two approaches were analyzed.Powder X-ray diffraction was demonstrated to be a powerful auxiliary implement to single-crystal X-ray diffraction in structure characterization,and its application can be popularized in the field of structure research of small organic molecules.     

A new estimate of global soil respiration from 1970 to 2008

Soil respiration(Rs)is one of the key processes that underline our understanding of carbon cycle in terrestrial ecosystems.Great uncertainty remains in the previous global Rs estimates with a difference of 70 Pg C a 1between the highest and lowest estimates.Thus,the present study aimed to estimate the global annual Rs and investigate the interannual and spatial variability in global annual Rs using a semi-mechanistic,empirically-based model which included climatic factors(temperature and precipitation)and topsoil(0–20 cm)organic carbon storage.About 657 published studies of annual Rs from 147 measurement sites were included in this meta-analysis.The global data sets from 1970 to 2008 on climate,surface air temperature,and soil properties were collected.The Monte Carlo method was used to propagate the simulation errors to global Rs.The results indicated that the mean annual global Rs was 94.4 Pg C a 1,increasing at roughly 0.04 Pg C a 1(~0.04%a 1)from 1970 to 2008.The Rs rate increased from colder,drier and less soil carbon-rich regions to warmer,moister and more carbon-rich regions.Highest Rs rates appeared in the tropical forest,while the lowest ones were in polar and desert regions.The annual Rs correlated directly with global temperature anomalies,suggesting that the interannual variability in temperature was responsible for the interannual variations in predicted global Rs.The global Rs increased from high-latitude zones to low-latitude zones.Further studies are recommended to explore the relationship between soil respiration and vegetation characters.     

拟对偶双边模与对偶环

左拟对偶双边模 _SM_R 可以被刻划成M_R 的任意子模K 和_SS 的任意左理想L 分别是_rM l_S (K ) 和 l_S r_M( L ) 的一个直和项.对一个左拟对偶双边模_SM_R, 有以下结论: ( 1) _SM 为Kasch模; ( 2) r_Ml_S ( Soc( M_R ) ) = Soc(M_R ) , l_S r_M ( Soc( _S^S) ) = Soc( _SS) ;( 3) l_S ( Soc(M_R ) ) J ( S) , r_M ( Soc( _SS) ) Rad(M_R ) ; ( 4) 若 M_R 为 CS- 模,则 Soc( M^R ) _eM_R ; ( 5) 若 M_R 是非M - 奇异的,则M 是半单的; ( 6) 若 M_R 在[ M] 中投射且 M_R 半单,则 M 是非M - 奇异模.并且还得出, 若 R 是左对偶环或左拟对偶环,则R 是半单环当且仅当R 非奇异.     

料丝自加压式挤出机加料段不溢料条件分析

借助未熔丝材的活塞作用,部分熔融沉积造型(FDM)技术靠料丝插入的驱动力将熔融材料挤出.在分析加料段中熔融物料流变特点的基础上,找出确保熔融物料不会从料丝插入口间隙处溢出的三个影响因素(P/z、表观粘度ηa和料丝半径r0),得出料丝插入速度VS应当大于临界速度VS0.     

具有二阶扰动和疫苗接种的随机霍乱传染病模型的平稳分布

针对一类具有二阶扰动和疫苗接种的随机霍乱传染病模型,得到了一个关键条件R0S.然后利用随机Lyapunov分析法以及It?公式,证明了当R0S>1时,随机霍乱传染病模型存在遍历平稳分布.因为模型具有二阶扰动,在证明中构造了新颖的随机Lyapunov函数.证明方法可以应用到类似的模型中.     

S-wave velocity of the crust around Tianshan Mountains inverted from seismic ambient noise tomography

We process ambient noise data from seismic stations deployed in central Asia to determine the crustal shear wave velocity structure beneath the Tianshan Mountians and surrounding area. About 748 inter-station Rayleigh wave empirical Green’s functions have been recovered to estimate the phase velocity dispersions over periods from 6 to 50 s using the image transformation technique. Results show that for short periods (6–20 s), the distribution of Rayleigh wave phase velocities is generally consistent with surface geology, with high velocities corresponding to mountain ranges and low velocities to sedimentary basins. Along two profiles, which trend from NE-SW and NW-SE, the shear wave velocity shows a pair of high velocity anomalies dipping in opposite directions beneath the Tianshan Mountains. At shallow depths, those high velocity anomalies roughly correlate with areas where the mountain front and the surrounding basin are connected. The profiles also show a narrow zone beneath the Tianshan Mountains, which may represent a route for the upwelling from upper mantle. Those observations suggest that the underthrusting of the Tarim Basin and Kazakh Shield combine with the weakness of the crust, which is heated by the upwelling from upper mantle, may play an important role on the reactivation of the Tianshan Mountains associated with the India-Eurasia collision.     

Zircon U/Pb dating and Hf-O isotopes of the Zhouan ultramafic intrusion in the northern margin of the Yangtze Block, SW China: Constraints on the nature of mantle source and timing of the supercontinent Rodinia breakup

The Zhouan ultramafic intrusion in the northern margin of the Yangtze Block is mainly composed of lherzolite.Zircon grains selected from lherzolite are irregular in shape with distinct oscillatory and sector zoning and have Th/U ratios ranging from 0.8 to 10.6,indicating a magmatic origin.The weighted average 206 Pb/238 U age is 637±4 Ma (2σ,n=15),which can be considered as the crystallization age of the Zhouan intrusion.Zircon grains have δ18O values ranging from 5.2‰ to 7.0‰,with an averaged value of 5.8±0.4‰ (1σ,n=33),similar to the mantle δ18O value of zircon.Their 176Hf/177Hf(t) ratios range from 0.282410 to 0.282594 with εHf(t) values ranging from 1.3 to 7.6,lower than the corresponding value of the depleted mantle (～15),indicating an enriched mantle source.The enriched mantle source may have generated from a metasomatized lithospheric mantle with subducted slab.A number of ～635 Ma mafic-ultramafic intrusions in the Suizao basin are associated with coeval bimodal volcanics of the Yaolinghe Formation,indicating a continental rift setting.The ～635 Ma magmatic event in this region may represent the product of the last breakup of the Rodinia supercontinent in the northern margin of the Yangtze Block at Neoproterozoic.     

5,5’-偶氮四唑-5-氮氧化物钠五水合物的晶体结构及相关理论研究

化合物5,5’-偶氮四唑钠（2）在稀盐酸中分解得到5-肼基四唑盐酸盐（3）,5-肼基四唑盐酸盐与氢氧化钠中和后除去产物中的NaCl,在甲醇中重结晶得到5,5’-偶氮四唑-5-氮氧化物钠五水合物（4）,采用MS,元素分析等对这些化合物进行表征. 用X射线单晶衍射法测定获得了化合物 3 和4的晶体数据. 化合物3属于单斜晶系,P2（1）/n空间群,其晶胞参数a=0.438（2）nm,b=2.395 6（2）nm,c=0.493 6（2）nm,Z=4,V=0.546（4）nm3,D_c=1.659 g/cm3,F（000）=280;化合物 4属于三单斜晶系,P-1空间群,其晶胞参数a=0.715 81（19） nm,b=0.766 3（2）nm,c=1.193 3（4） nm,Z=2,V=0.602 7（3） nm3,D_c=1.742 g/cm3,F（000）=324.      

φ混合序列自正则加权和的中心极限定理

设｛X_n, n≥1｝为一严平稳φ混合随机变量序列, EX=0,V²_n为一实数阵列, 利用随机变量阵列的弱收敛定理, 在较一般的条件下, 证明了自正则加权和｛S_n/V_n, n≥1｝的中心极限定理, 改进并推广了已有混合序列自正则化中心极限定理的相关结果.     

Initial-boundary value problem for a class of quasilinear degenerate parabolic equations

In this work, we study the quasilinear initial-boundary value problem $\sum\limits_{i, j = 1}^m {X_i^ * A_{i j} (x, t, u)X _j u} + \sum\limits_{j = 1}^m {B_j (x, t, u)X _j u + C} (x, t, u) = 0$ , in ]0,T[×Ω;u| _t=0 =φ, onΩ;u=ψ, on [0,T[×?Ω, whereX={X ₁, ...,X _m } is a system of real smooth vector fields which is defined on an open domainM of R ⁿ , and satisfies the Hörmander's condition, Ω?M. Assume that ?Ω is non characteristic for the systemX ₁,...,X _m . Under some hypothesis for the boundary of domain and the elliptic structure condition for nonlinear coefficientsA _ij ,B _j ,C, (i, j=1, ...,m), we have proved that the existence and regularity of solution for aboveinitial-boudary value problems.