Luminomagnetic Nd3+ doped fluorapatite coated Fe3O4 nanostructures for biomedical applications

Luminomagnetic nanostructured Nd³⁺ doped fluorapatite (FAP) coated Fe₃O₄ nanoparticles were produced by hydrothermal method. X-ray diffraction analysis indicates that the prepared nanoparticles contain both FAP and Fe₃O₄ phases. Electron microscope analysis shows the formation of nanoparticles of Fe₃O₄ encased in rod shaped FAP nanoparticles of average length 40 nm. Magnetic measurements confirm the room temperature superparamagnetic nature of the nanoparticles with saturation magnetization value up to 7.8 emu/g. The prepared nanoparticles display strong near infrared (NIR) emission at 1060 nm under 800 nm excitation. Cell viability studies for 72 hour demonstrate the survival rate of over 84% with 500 μg/mL concentration indicating the good cytocompatibility of the prepared materials. The present Nd³⁺ doped FAP coated Fe₃O₄ nanostructure provides an excellent multifunctional platform for diagnostics and therapeutic applications.     

Non-invasive Raman identification of crystalline and glassy phases in a 1781 Sèvres Royal Factory soft paste porcelain plate

A Raman study of a Sèvres soft paste (frit) porcelain plate allowed the identification of both the crystalline and amorphous phases. Cristobalite and pseudowollastonite gave main Raman signatures in the body where also tridymite, amorphous alkali silicate glass and lead arsenate apatite were detected. Na_0.4K_0.1Ca_0.5Pb₄(AsO₄)₃ lacunar apatite is identified as opacifier in blue and green overglaze enamel. Pb-Sb-reach pyrochlore (Naples Yellow) pigment was found in yellow and green overglaze enamels. The orange hue is obtained by superposing a hematite bearing red paint stroke over the yellow. These results are compared to those previously obtained by detailed OM, SEM, XRD and XRF analyses. Some of the phases identified by XRD (quartz, tridymite) are hardly detected by Raman and vice versa cristobalite was not found by XRD, most probably due to its low amount.     

A novel snail-inspired bionic design of titanium with strontium-substituted hydroxyapatite coating for promoting osseointegration

As the population ages,more and more people are suffering from osteoarthritis (OA),resulting in an increasing requirement for joint implants.Surface modification to improve the topology and compo-sition of the implants has been proved to be an effective way to improve the primary stability and long-term success rate of joint implants.In this work,a bionic micro/nano-structure accompanied with a strontium-substituted hydroxyapatite (SrHA) coating was fabricated on titanium (Ti) surface via elec-trochemical corrosion,ultrasonic treatment,and hydrothermal deposition methods.The in vitro study demonstrated that the bionic structure and the bioactive apatite could synergistically increase the expres-sions of integrin-related gene (ITG α5β1) and osteoblastic genes (Col-I and OCN),and thus promote osteoblast growth.In addition,owing to the anti-bone resorption property of Sr2+,the coating could effectively inhibit osteoclast differentiation and proliferation.In a word,the prepared samples not only promoted osteogenesis but also inhibited osteoclastogenesis.The in vivo experiment via a rabbit model found that the bionic structured surface provided the pore for new bone ingrowth,which was beneficial to the mechanical interlocking between the implant and bone.Moreover,the bionic structure and bioactive SrHA coating had a synergistic effect on promoting bone formation,osseointegration,and bone-implant bonding strength.This study therefore presented a new strategy to fabricate bio-functionalized Ti-based implants for potential application in orthopedics field.     

Insights into the In Vitro Formation of Apatite from Mg-Stabilized Amorphous Calcium Carbonate

A protein-free formation of bone-like apatite from amorphous precursors through ball-milling is reported. Mg²⁺ ions are crucial to achieve full amorphization of CaCO₃. Mg²⁺ incorporation generates defects which strongly retard a recrystallization of ball-milled Mg-doped amorphous calcium carbonate (BM-aMCC), which promotes the growth of osteoblastic and endothelial cells in simulated body fluid and has no effect on endothelial cell gene expression. Ex situ snapshots of the processes revealed the reaction mechanisms. For low Mg contents (<30%) a two phase system consisting of Mg-doped amorphous calcium carbonate (ACC) and calcite “impurities” was formed. For high (>40%) Mg²⁺ contents, BM-aMCC follows a different crystallization path via magnesian calcite and monohydrocalcite to aragonite. While pure ACC crystallizes rapidly to calcite in aqueous media, Mg-doped ACC forms in the presence of phosphate ions bone-like hydroxycarbonate apatite (dahllite), a carbonate apatite with carbonate substitution in both type A (OH⁻) and type B (PO₄³⁻) sites, which grows on calcite “impurities” via heterogeneous nucleation. This process produces an endotoxin-free material and makes BM-aMCC an excellent “ion storage buffer” that promotes cell growth by stimulating cell viability and metabolism with promising applications in the treatment of bone defects and bone degenerative diseases.     

The initial and residual value for subterranean clover of phosphorus from crandallite rock phosphates,apatite rock phosphates and superphosphate

The residual value of phosphorus from superphosphate, crandallite rock phosphate (Christmas Island C-grade ore), 500°C calcined crandallite rock phosphate (Calciphos) and apatite rock phosphate from Queensland, Australia, was measured in a 6 year field experiment sited on lateritic soil in south-western Australia. Different amounts of each fertilizer were applied at the commencement of the experiment, and either left on the soil surface or mixed through the soil by cultivating to a depth of about 10 cm. Dry matter production of subterranean clover measured in spring (August) and bicarbonate-extractable phosphorus determined from soil samples collected in summer (January–February) were used as indicators of fertilizer effectiveness.The effectiveness values calculated for each fertilizer each year were similar for the treatments that were left on the soil surface and those which were mixed through the soil. The effectiveness of both ordinary and triple superphosphate were similar each year. They were the most effective fertilizers for the duration of the experiment. Using pasture yield as an indicator, the effectiveness of the superphosphates decreased by about 50% from year 1 to year 2, and by a further 10% over the remaining 4 years. Using bicarbonate-extracted soil phosphorus the effectiveness of both superphosphates decreased in a more uniform fashion by about 60% from year 2 to year 6. The effectiveness of all the rock phosphate fertilizers was approximately constant through time. As calculated from yield and bicarbonate-soluble phosphorus values, C-grade ore, Calciphos and the Queensland apatite were respectively 5%, 20% and 7% as effective as freshly applied superphosphate.The proportion of the total phosphorus content present in the rock phosphates which was initially soluble in neutral ammonium citrate was a poor predictor of the effectiveness of the phosphorus from these fertilizers determined using herbage yield or the amount of bicarbonate — soluble phosphorus extracted from the soil.The bicarbonate soil test did not predict the same future production for superphosphate and some of the rock phosphates in years 2 and 3 of the experiment, indicating that different soil test calibration curves are needed for the different fertilizers.     

A novel Eu3+‐ and self‐activated vanadate phosphor of Ca4La(VO4)3O with oxyvanadate apatite structure

Pure and Eu³⁺‐activated Ca₄La(VO₄)₃O phosphors were prepared via three‐step solid‐phase synthesis. The phase formation and structure were investigated by X‐ray diffraction (XRD) with Rietveld refinements. All the samples crystallized in an apatite‐type structure. The morphological properties were measured via by SEM and EDS measurements. Ca₄La(VO₄)₃O is a new vanadate optical material with a direct band feature and a band energy of 3.1 eV. The undoped Ca₄La(VO₄)₃O phosphor presents self‐activated yellow luminescence from 400 nm to 750 nm with a maximum wavelength of 525 nm originating from VO₄ groups. Luminescence characteristics of Ca₄La(VO₄)₃O indicate that the phosphor is not sufficient for practical applications. In Eu³⁺‐activated Ca₄La(VO₄)₃O, there is an efficient energy transfer from VO₄ to Eu³⁺ ions. The luminescence spectra, concentration quenching, decay curves, color chromaticity, and quantum efficiencies (QE) of Ca₄La(VO₄)₃O:Eu³⁺ were investigated. The phosphor presents optimal Eu³⁺ doping concentration of about 20 mol%. The dominant red emission in Ca₄La(VO₄)₃O:Eu³⁺ is 615 nm from electronic ⁵D₀→⁷F₂ dipole transitions. The quantum efficiency and the luminescence stability of the pure and Eu‐activated Ca₄La(VO₄)₃O were reported. The luminescence was discussed on the structural characteristics.     

In vitro biomimetic deposition of apatite on alkaline and heat treated Ti6A14V alloy surface

Titanium alloy (Ti6A14V) substrates, having the ability of biomimetic calcium phosphate-based materials, especially hydroxyapatite deposition in a simulated body fluid (SBF) means of chemical treatment (alkaline treatment) and subsequent heat treatment, was studied. The effects of alkaline treatment time, concentration and heat treatment temperature on the formation of calcium phosphate (carbonate-hydroxyapatite) on Ti6A14V surface were examined. For this purpose, the metallic substrates were treated in 0, 5 and 10 M NaOH solutions at a temperature of 60 or 80°C for 1 and 3 days. Subsequently the substrate was heat-treated at 500, 600 and 700°C for 1 h for consolidation of the sodium titanate hydrogel layer. Finally, they were soaked in SBF for 1 and 3 days. The substrate surfaces were characterized by the techniques commonly used for bulk material such as scanning electron microscopy (SEM) and thin film X-ray diffraction (TF-XRD). With regard to the SEM and TF-XRD results, the optimum process consists of 3 days soaking in 5 M NaOH in 80°C and subsequent heat treatment at 600°C for 1h. It is worth mentioning that the results showed that the apatite formed within 3 days on the specimen surfaces, however, there was no sign of apatite formation in the control samples (without alkaline and heat treatment) which was treated for up to 3 days immersion in SBF.     

含稀土磷灰石精矿酸浸试验研究

分别用硝酸、硫酸和盐酸对某复杂含稀土磷灰石精矿进行浸出试验。结果表明,硝酸浸出时,磷灰石中绝大部分磷进入溶液,而稀土则分散于浸出液和渣中;硫酸浸出时,稀土浸出率较低,磷浸出率较高,可控制合适的条件初步分离精矿中的磷和稀土;盐酸浸出时,磷和稀土的浸出率均较高,可以通过溶剂萃取的方法从溶液中分离磷和稀土。     

蓬莱9-1构造新生代构造演化:磷灰石裂变径迹证据

作为国内最大的中生界花岗岩潜山油田,蓬莱9-1构造中生界花岗岩的构造演化直接制约着储层的分布及好坏,而区域构造演化证实花岗岩在整个新生代经历了长期的暴露和改造过程。通过磷灰石裂变径迹技术对该构造中生界花岗岩新生代的构造演化进行了详细研究,结果表明该构造新生代热史分为4个降温期和2个升温期共6个阶段,结合区域构造背景可将新生代构造演化进一步划分为稳定期(65~51 Ma)、低速隆升期(51~34 Ma)、高速隆升期(34~18 Ma)、沉降期(18~5 Ma)和成藏期(5 Ma至今)5个阶段。不同隆升期花岗岩剥蚀速率存在明显差异,其高速隆升期剥蚀速率可达110.7 m/Ma,新生代平均剥蚀量约2 260 m。成藏研究证实构造演化与花岗岩成储成藏有着密切联系,隆升期的风化壳形成和沉降期的泥岩沉积使花岗岩具备了良好的储盖组合,成藏期的新构造运动又为油气的运移和充注提供了有利条件。     

玻璃基生物骨水泥内部纳米羟基磷灰石的形成研究

以CaO-SiO2-P2O5系统生物玻璃和磷酸铵调和液混合制得玻璃基生物骨水泥(GBC),利用XRD、FTIR和SEM对GBC的产物晶相、化学组成和内部显微结构进行了分析,并对其力学性能进行了测试。实验结果表明,随着浸泡时间的增加GBC中的玻璃相逐步向羟基磷灰石(HAP)微晶转化,生成的磷灰石为弱结晶度的类骨状碳酸羟基磷灰石微晶,这些微晶主要分布于玻璃粉末的界面之间,端面尺寸在30～50nm,这表明GBC中所生成的HAY晶体与人体骨有很大的相似性,因而会具有良好的生物活性。对力学性能测试的结果表明,随着浸泡时间的增加GBC的抗压强度逐步增加,在30天时可达到80MPa。因而GBC不仅具有良好的生物活性,而且具有一定的力学强度。