大陆玄武岩原始水含量的测定及其对源区组分的制约

理解大陆板内玄武岩的源区组成和成因是认识地幔动力学过程和化学不均一性的重要途径。由于不同地幔端员具有不同的水含量及水与其它不相容元素的比值(如H2O/Ce),原始水含量的测定对于认识玄武岩的源区组成将会提供新的信息。玄武岩玻璃和斑晶中的熔体包裹体是获得海洋玄武岩原始水含量的主要样品,但是不适合于大陆玄武岩,因为大陆玄武岩玻璃由于强烈的去气作用不能反映真实水含量,而大陆玄武岩斑晶中的熔体包裹体少而小,不易获得足量、准确的数据。本文介绍一种最近发展起来的推断大陆玄武岩原始水含量的方法,即利用红外光谱测定玄武岩中单斜辉石斑晶的水含量,然后结合水在单斜辉石与玄武质熔体中的分配系数来反演与斑晶平衡的熔体水含量,进而估计原始玄武质岩浆的水含量。文中详细叙述了方法的适用性、误差的估计以及具体的操作流程,并通过东北双辽和华北太行山新生代玄武岩的研究实例,展示了玄武岩水含量对于源区组成的有力制约。

A novel approach for fabricating a CNT/AlSi composite with the self-aligned nacre-like architecture by cold spraying

A fully dense carbon nanotubes (CNTs) reinforced AlSi matrix composite with the multiscale nacre-like architecture was designed and successfully realized by flake powder metallurgy followed by cold spraying (CS). The nanolaminated and ultrafine-grained structure initially created in the CNT/AlSi flaky powder was perfectly conserved, due to the typical ‘cold’ feature of CS. As discussed based on finite element analysis and single splat observation, self-alignment behavior of the flaky powders during impact also allowed the formation of the microlaminated structure. Hence, the scalable CS technique opens a new avenue for bioinspired material design and fabrication with complex shape.

Intercalation of Ciprofloxacin in Naturally Occurring Smectite from Bana: Potentiality as Drug Delivery System and Antimicrobial Effects on <i>Escherichia coli</i>and <i>Staphylococcus aureus</i>

Ciprofloxacin (CFX) was loaded on Bana clay (Cameroon) and CFX loaded-clays have been evaluated as drug delivery system. Raw clays and CFX loaded compounds have been characterized by some physico-chemicals methods. In vitro release studies have been done in gastric and phosphate buffer experimental mediums;bacteriological studies have been made up on Escherichia coli and Staphylococcus aureus. X-ray diffractometry patterns of loaded compounds show a basal spacing increasing due to CFX intercalation. On Fourier-Transformed Infrared spectrometry spectra, appearance of CFX characteristic bands and shifting of certain bands already presents on clay confirmed CFX intercalation. After 96 h of CFX released from release mediums, prolonged and continue profiles have been observed. Diffusion tests displayed an inhibition radius of ~2 cm on gelose seeded with Escherichia coli and Staphylococcus aureus due to CFX. The overall results show a modified release of ciprofloxacin with an effective antibacterial activity, giving the way for a new ciprofloxacin drug delivery system using Bana clay as carrier.

New Polysiloxane Surfaces Modified with <i>ortho-, meta-</i>or <i>para</i>-Nitrophenyl Receptors for Copper Adsorption

Porous SiO2 has been chemically modified with functional ortho-, meta- or para-nitrophenyl moieties using the heterogeneous route. This synthetic route involved the reaction of carbaldehyde derivatives with 3-aminopropyl trimethoxysilane prior to immobilization on the support. The new modified surfaces have been characterized by elemental analysis, FT-IR, 13C NMR of the solid state, nitrogen adsorption-desorption isotherm, BET surface area, B.J.H. Pore sizes, thermogravimetry curves (TGA) and scanning electron microscope (SEM). The new materials exhibit good chemical and thermal stability. These products were employed as a Cu(II) adsorbent from aqueous solutions at room temperature using the batch technique. Flame atomic absorption spectrometry was used to determine the Cu(II) concentration in the filtrate after the adsorption process. The results indicate that under the optimum conditions, the maximum adsorption value for Cu(II) was 20.0 mg Cu(II) g-1 modified silica, whereas the adsorption capacity of the unmodified silica was only 1.0 mg Cu(II) g-1 silica. On the basis of these results, it can be concluded that it is possible to modify chemically SiO2 with functional groups and use it as adsorbents for metals in aqueous media.

Micro-alloying of Zn and Ca in vacuum induction casted bioresorbable Mg system:Perspectives on corrosion resistance,cytocompatibility,and inflammatory response

There is an increasing interest in biodegradable materials,such as magnesium,for orthopaedic implants.This is driven by their potential to address challenges like stress shielding and the need for secondary removal surgery.In this study,biodegradable magnesium alloys were produced using the Vacuum Induction Casting technique.The impact of micro-alloying Zn and Ca in Mg-xZn-0.2Ca(x=0.1,0.2,0.3,and 0.4 wt%)alloys on corrosion resistance,cytocompatibility,and early-stage inflammatory response was investigated.XRD and SEM-EDS analysis confirmed the presence of Ca_(2)Mg_(6)Zn_(3)secondary phases in all alloys.The Mg-0.3Zn-0.2Ca alloy exhibited the lowest corrosion rate and an elastic modulus of 36.8 GPa,resembling that of natural bone.Electrochemical measurements indicated a correlation between grain size and secondary phase volume fraction in explaining corrosion behaviour.In vitro degradation in simulated body fluid(SBF)for 21 days showed hydroxyapatite formation on alloy surfaces,aligning with electrochemical studies.In vitro cytotoxicity tests demonstrated the cytocompatibility of all alloys,with Mg-0.3Zn-0.2Ca having the highest cell viability over a 6-day cell culture.Investigation into the inflammatory response with RAW-Blue macrophages revealed the anti-inflammatory properties of Mg-0.3Zn-0.2Ca alloys.Micro-alloying with 0.3 wt%Zn and 0.2 wt%Ca enhanced mechanical properties,corrosion resistance,cytocompatibility,and immunomodulatory properties.This positions the Mg-0.3Zn-0.2Ca alloy as a promising biodegradable implant for bone fixation applications.

Silicone matrices for controlled dexamethasone release:toward a better understanding of the underlying mass transport mechanisms

Dexamethasone-loaded silicone matrices offer an interesting potential as innovative drug delivery systems,e.g.for the treatment of inner ear diseases or for pacemakers.Generally,very long drug release periods are targeted:several years/decades.This renders the development and optimization of novel drug products cumbersome:experimental feedback on the impact of the device design is obtained very slowly.A better understanding of the underlying mass transport mechanisms can help facilitating research in this field.A variety of silicone films were prepared in this study,loaded with amorphous or crystalline dexamethasone.Different polymorphic drug forms were investigated,the film thickness was altered and the drug optionally partially/completely exchanged by much more water-soluble dexamethasone‘phosphate’.Drug release studies in artificial perilymph,scanning electron microscopy,optical microscopy,differential scanning calorimetry,X-ray diffraction and Raman imaging were used to elucidate the physical states of the drugs and polymer,and of the systems’structure as well as dynamic changes thereof upon exposure to the release medium.Dexamethasone particles were initially homogeneously distributed throughout the systems.The hydrophobicity of the matrix former very much limits the amounts of water penetrating into the system,resulting in only partial drug dissolution.The mobile drug molecules diffuse out into the surrounding environment,due to concentration gradients.Interestingly,Raman imaging revealed that even very thin silicone layers(<20µm)can effectively trap the drug for prolonged periods of time.The physical state of the drug(amorphous,crystalline)did not affect the resulting drug release kinetics to a noteworthy extent.

中国东北小古里河高钾火山岩的水含量：对源区富钾组分的制约

近年来高钾（钾质）火山岩的成因问题越来越受到学术界的关注,特别是其地幔源区中富钾组分的来源.位于中国东北北部的五大连池、二克山、科洛（合称WEK）及小古里河玄武岩都是典型的高钾（钾质）火山岩.前人对这里做了大量的研究工作,但是对于源区中富钾组分来源还存在很大争议,主要包括：（1）来自于岩石圈地幔中含金云母的石榴石橄榄岩;（2）来自于过渡带中再循环的富钾占老沉积物．

Typical Oxygen Isotope Profile of Altered Oceanic Crust Recorded in Continental Intraplate Basalts

Recycled oceanic crust （ROC） has long been suggested to be a candidate introducing en- riched geochemical signatures into the mantle source of intraplate basalts. The different parts of oceanic crust are characterized by variable oxygen isotope compositions （δ^18O=3.7‰ to 13.6‰）. To trace the sig- natures of ROC in the mantle source of intraplate basalts, we measured the δ^18O values of clinopyroxene （cpx） phenocrysts in the Cenozoic basalts from the Shuangliao volcanic field, NE China using secondary ion mass spectrometer （SIMS）. The δ^18O values of the Shuangliao cpx phenocrysts in four basalts ranging from 4.10‰ to 6.73‰ （with average values 5.93‰±0.36‰, 5.95‰±0.30‰0, 5.58‰±=0.66‰e, and 4.55‰±= 0.38‰, respectively） apparently exceed those of normal mantle-derived cpx （5.6‰±0.2‰） and fall in the typical oxygen isotope range of altered oceanic crust. The δ^18O values display the negative correlations with the Eu, Sr anomalies of whole rocks and erupted ages, demonstrating that （1） the ROC is the main enriched component in the mantle source of the Shuangliao basalts and （2） the contributions of ROC var- ied with time. The basalt with the lowest δ^18O value is characterized by a significant K positive anomaly, highest H2O/Ce and Ba/Th ratios, suggesting that the mantle source of basalts with low δ^18O can also in- clude a water-rich sediment component that may be the trigger for partial melting. Considering the continuous subduction of the Pacific slab, the temporal heterogeneity of the source components is likely to be caused by the Pacific slab subduction.

Water content of the Xiaogulihe ultrapotassic volcanic rocks, NE China: implications for the source of the potassium-rich component

Water has become an effective means to trace the mantle source of basaltic magmas recently. To investigate the source of the potassium-rich component in the Xiaogulihe ultrapotassic volcanic rocks of NE China, we measured the water content of clinopyroxene （cpx） phenocrysts by Fourier transform infrared spectrometry and calculated the H2O content of the equilibrated melts according to the partition coefficients of H2O between cpx phenocrysts and basaltic melts. The estimated H2O content of the ＂primary＂ magmas is low （0.36 wt%-0.50 wt%）, within the range of mid-ocean ridge basalts and ocean island basalts, while it is obviously lower than that of backarc basin basalts and island arc basalts. The calculated H20/Ce ratio of the ＂primary＂ magmas is about 15, which might be similar to that of the dehydrated sediments （〈100）, but observably lower than that of the normal depleted mantle （DMM, H2O/Ce = 150-210）. The low water content and especially low H2O/Ce ratio of the ＂primary＂ magmas demonstrate that the K-rich component of these ultrapotassic volcanic rocks seems unlikely tooriginate from K-bearing hydrous minerals （such as phlogopite） in metasomatic subcontinental lithospheric mantle. Combined with the low 206pb/204pb ratios, moderately high 87Sr/86Sr ratios of the bulk rocks and the high δ18O values of olivine phenocrysts, we suggest that the K-rich component in the mantle source of the Xiaogulihe ultrapotassic volcanic rocks may come from ancient continental-derived sediments which dehydrated significantly during subduction （e.g., dry K-hollandite）.