Preparation of degradable polypropylene by an addition of poly(ethylene oxide) microcapsule containing TiO2. Part III: Effect of existence of calcium phosphate on biodegradation behavior

In this work, biodegradation behavior of a novel polypropylene (PP) composite containing a poly(ethylene oxide) (PEO)/modified TiO₂ microcapsule was studied with an oxo-biodegradation test combined with a photodegradation treatment (using a high-pressure mercury vapor lamp for 24 h of the irradiation at 30 °C in air) and a soil burial test (for 45 days of incubation at 20 °C). The modification of the TiO₂ was performed by the synthesis of octacalcium phosphate intercalated with succinic acid ion (OCPC). The existence of the microcapsule brought about higher PP photo- and biodegradation rates. In the photodegraded PP composite, active colonies of some microorganisms were observed. By comparing with the PP composite without the OCPC modification, it was found that the active behavior of the microorganisms was due to the inorganic phosphates, which were supplied by the dissolution of the OCPC during the photodegradation. In addition, the photodegraded parts in the composite were completely metabolized by the microorganisms. However, the microorganisms had the inability to metabolize other parts such as the PP crystalline phase.     

Rational Design of a Near‐infrared Fluorescence Probe for Ca2+ Based on Phosphorus‐substituted Rhodamines Utilizing Photoinduced Electron Transfer

Fluorescence imaging in the near‐infrared (NIR) region (650–900 nm) is useful for bioimaging because background autofluorescence is low and tissue penetration is high in this range. In addition, NIR fluorescence is useful as a complementary color window to green and red for multicolor imaging. Here, we compared the photoinduced electron transfer (PeT)‐mediated fluorescence quenching of silicon‐ and phosphorus‐substituted rhodamines (SiRs and PRs) in order to guide the development of improved far‐red to NIR fluorescent dyes. The results of density functional theory calculations and photophysical evaluation of a series of newly synthesized PRs confirmed that the fluorescence of PRs was more susceptible than that of SiRs to quenching via PeT. Based on this, we designed and synthesized a NIR fluorescence probe for Ca²⁺, CaPR‐1 , and its membrane‐permeable acetoxymethyl derivative, CaPR‐1 AM , which is distributed to the cytosol, in marked contrast to our previously reported Ca²⁺ far‐red to NIR fluorescence probe based on the SiR scaffold, CaSiR‐1 AM , which is mainly localized in lysosomes as well as cytosol in living cells. CaPR‐1 showed longer‐wavelength absorption and emission (up to 712 nm) than CaSiR‐1 . The new probe was able to image Ca²⁺ at dendrites and spines in brain slices, and should be a useful tool in neuroscience research.     

A Stable Calcium Alumanyl

A seven-membered N,N′-heterocyclic potassium alumanyl nucleophile is introduced and utilised in the metathetical synthesis of Mg−Al and Ca−Al bonded derivatives. Both species have been characterised by experimental and theoretical means, allowing a rationalisation of the greater reactivity of the heavier group 2 species implied by an initial assay of their reactivity.     

“S”-shaped isopolyoxotungstate cluster decorated by calcium ions

One novel "S"-shaped isopolyoxotungstate Ca2(H2O)12{Ca4(H2O)18[H2W11O37]2}·20H2O (1) has been successfully synthesized by the conventional aqueous solution method. Single-crystal X-ray diffraction analysis revealed that compound 1 crystallized in triclinic system, space group P-1, with lattice constants a=12.591(3)Å, b=12.738(3)Å, c=17.961(4)Å, α=98.97(3)8, β=99.85(3)8, γ=93.42(3)8. The "S"-shaped cluster was built from two {W11} subunits, four Ca2+linking units and two {Ca(H2O)6}2+ decorating fragments. The electrochemical properties of 1 have been investigated in details.     

UVC emitting phosphors obtained by spray pyrolysis

The broadband inter-configurational (4f¹5d¹→4f²) emission of Pr³⁺ doped in lanthanum orthophosphate (LaPO₄) and in calcium pyrophosphate (Ca₂P₂O₇) has been investigated under plasma excitation. The synthesis by spray pyrolysis at moderate temperature followed by a controlled annealing proves to be a very efficient way to produce good quality UVC emitting phosphor Ca_1.92Pr_0.04Na_0.04P₂O₇ (α phase). The emission of this phosphor in the wavelength range 200-350 nm has been measured with a prototype device, which can be employed for anti-microbial testing.     

Role of Al2O3 in upconversion and NIR emission in Tm and Er codoped calcium fluoro phosphorous silicate glass system

In this study, the principal role of Al₂O₃ on the features of the photoluminescence spectra of Tm³⁺ ion and upconversion phenomenon in Tm³⁺ and Er³⁺ codoped CaF₂−Al₂O₃−P₂O₅−SiO₂ glass system has been investigated. The concentration of Al₂O₃ is varied from 2 to 10 mol% while that of Er³⁺ and Tm³⁺ is fixed. IR and Raman spectral studies have indicated that there is a gradual increase in the degree of disorder in the glass network with increase in the concentration of Al₂O₃ up to 6.0 mol%. This is attributed to the presence of Al³⁺ ions in octahedral positions in larger proportions. When the glasses are doped with Tm³⁺ ions, the blue and red emissions were observed, whereas in Er³⁺ doped glasses blue, green and red emissions were observed. When the glasses are codoped with Tm³⁺ and Er³⁺ ions and excited at 790 nm, all the three emission lines were observed to be reinforced, especially in the glasses mixed with 6.0 mol% of Al₂O₃. The IR emission band detected at about 1.8 μm due to ³F₄→³H₆ transition of Tm³⁺ ions is also observed to be strengthened due to codoping. The reasons for enhancement in the intensity of various emission bands due to codoping have been identified and discussed with the help of rate equations for various emission transitions.     

Preparation and characterization of hydrophobic calcium hydroxyapatite particles grafting oleylphosphate groups

Grafting of oleylphosphate (OP) molecules to the surface of calcium hydroxyapatite particles (HAP) was carried out by a coprecipitation method with a Ca(OH)₂–H₃PO₄ system in the presence of disodium oleylphosphate (DSOP). All the particles exhibited a single-crystal nature with rod-like shape and were elongated along c-axis from 36 to 122 nm in particle length with an increase in the concentration of DSOP. It was suggested that 084% of the phosphate ions exposed on the ac or bc faces of the HAP particles are exchanged with phosphate ions of DSOP molecules directing oleyl groups outward. The hydrophobicity of OP-grafted HAP particles was enhanced with an increase in the DSOP concentration. This high surface hydrophobicity was further confirmed by water adsorption experiments. The materials with the surface oleyl groups adsorbed much less water than the HAP particles produced without DSOP.     

Characterization of the health of southern Appalachian red spruce (Piceae rubens) through determination of calcium, magnesium, and aluminum concentrations in foliage and soil

The red spruce (Picea rubens) is a conifer whose southern native range is limited to high elevation sites in the Appalachian Mountains. Red spruce decline has been reported to involve atmospheric deposition of acidic anions, which may affect cation mobility in soil, primarily calcium, magnesium, and aluminum. In this work, the concentrations of these elements were determined in red spruce foliage and surrounding soil at high elevation locations in the Great Smoky Mountains and on the Blue Ridge Parkway by inductively coupled plasma optical emission spectrometry (ICP-OES). Few differences in foliar or soil concentrations were observed at the sites, indicating that elevation and geography do not affect these values. A comparison of foliar concentrations in seedlings, saplings, and mature trees demonstrated few differences, suggesting that life stage does not affect these elemental concentrations. A previously-developed model to estimate forest health using soil calcium/aluminum ratios suggested that all sites had a significant risk of adverse health effects. However, comparisons of foliar calcium/aluminum ratios and calcium and magnesium concentrations to values obtained in the mid-1990s showed an improvement in these parameters, presumably due to decreased acidic deposition.     

火焰原子吸收法测鼠肺组织总钙

本文经十二烷基硫酸钠，十二烷基二甲基苄基溴化铵和壬基酚基聚氧乙烯醚复配而成的混合微乳液体系对鼠肺组织进行浸取前处理，用火焰原子吸收法测定了其中的钙含量。用混合微乳液法与溶液法进行了一系列对照试验，结果表明：在灵敏度、精密度、选择性、工作曲线线性方面均优于后者。检出限为１．９２ｎｇ·ｃｍ－３，相对标准偏差为１．９２％（ｎ＝１０），工作曲线线性范围０～２０μｇ·ｃｍ－３，线性回归系数ｒ＝０．９９９８，用于鼠肺组织中总钙的测定，结果与样品高温灰化法溶液ＦＡＡＳ结果一致。     

ESI源质谱表征氯化钙和氯化镁

用ESI源质谱对氯化镁和氯化钙进行了定性的检测，所得谱图更加全面直观地表征了氯化钙和氯化镁在水溶液中的存在形式。