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PubMed2006

Increased complexity of radiation-induced chromosome aberrations consistent with a mechanism of sequential formation.

Complex chromosome aberrations (any exchange involving three or more breaks in two or more chromosomes) are effectively induced in peripheral blood lymphocytes (PBL) after exposure to low doses (mostly single particles) of densely ionising high-linear energy transfer (LET) alpha-particle radiation. The complexity, when observed by multiplex fluorescence in situ hybridisation (m-FISH), shows that commonly four but up to eight different chromosomes can be involved in each rearrangement. Given the territorial organisation of chromosomes in interphase and that only a very small fraction of the nucleus is irradiated by each alpha-particle traversal, the aim of this study is to address how aberrations of such complexity can be formed. To do this, we applied theoretical "cycle" analyses using m-FISH paint detail of PBL in their first cell division after exposure to high-LET alpha-particles. In brief, "cycle" analysis deconstructs the aberration "observed" by m-FISH to make predictions as to how it could have been formed in interphase. We propose from this that individual high-LET alpha-particle-induced complex aberrations may be formed by the misrepair of damaged chromatin in single physical "sites" within the nucleus, where each "site" is consistent with an "area" corresponding to the interface of two to three different chromosome territories. Limited migration of damaged chromatin is "allowed" within this "area". Complex aberrations of increased size, reflecting the path of alpha-particle nuclear intersection, are formed through the sequential linking of these individual sites by the involvement of common chromosomes.

Cell Cycle↗

PubMed1995

Pulmonary carcinogenicity of repeated inhalation exposure of rats to aerosols of 239PuO2.

To study the long-term biological effects of repeated inhalation exposure to 239PuO2, 84-day-old rats were exposed to aerosols of 239PuO2 to re-establish desired 239Pu lung burdens of 26, 80 or 250 Bq every other month for 1 year (seven exposures). Other rats were exposed once at 84 or 450 days of age to achieve desired initial lung burdens of 30, 90, 280 or 850 Bq. The incidences of lung tumors were not significantly different (Fisher's exact test; P > 0.05) in groups of rats with similar lifetime mean alpha-particle doses to the lungs of 0.90 +/- 0.39 to 4.4 +/- 1.8 (+/- SD) Gy, whether exposed once or repeatedly. Among rats with mean alpha-particle doses of 12 +/- 2.4 to 10 +/- 2.1 Gy to the lungs after single or repeated exposures, respectively, the crude incidence of lung tumors was significantly less (Fisher's exact test; P < 0.05) in the rats exposed repeatedly. Times to death of rats with lung tumors were compared among groups with similar alpha-particle doses to the lungs after single or repeated exposure to 239PuO2. Those that died with lung tumors after repeated exposures died at times similar to (Mantel-Cox statistic; P > 0.05) or later than (Mantel-Cox statistic; P < 0.05) those for 84-day-old rats exposed once. The risk of lung tumors in rats per unit dose to the lungs was less in the rats exposed repeatedly than in those exposed once. It was concluded that alpha-particle doses to the lung of rats exposed repeatedly to aerosols of 239PuO2 were not more carcinogenic and possibly were less carcinogenic than the dose after a single inhalation exposure when rats with similar lifetime alpha-particle doses to the lungs were compared. The relative biological effectiveness in rats of the alpha-particle dose to the lungs from inhaled 239PuO2 relative to beta-particle doses to the lungs from inhaled 144CeO2 was 21 +/- 3.

Administration, Inhalation↗

PubMed1981

[Superimposition alpha-autoradiography for basic study of neutron capture therapy (author's transl)].

Since Locher suggested the possibility of neutron capture therapy, a number of investigators have been making efforts to establish clinical application of this treatment. For success of this therapy one of the keys is to develop a proper boron compound with selective accumulation and high concentration in the tumor. So far, sodium mercaptoundecahydrododecaborate, Na2B12H11SH is the best candidate for this purpose with its high concentration and selectivity shown by chemical analysis. Nevertheless, histological study of boron uptake to know fine distribution in tissue is inevitable for evidence of effectiveness of clinical therapy. Cytological effects in neutron capture therapy largely depend on close association of B-10 with the tumor cell. B-10, being non-radioactive isotope, can not be used as a tracer for autoradiographical study of boron distribution in tissue. Instead, alpha particles produced by (n, alpha) reaction can be used for autoradiography which demonstrates not only location of boron in tissue but tracks by alpha particles expected to occur in actual neutron irradiation. Dielectric organic polymer has been calling attention for its ability to register heavy particles which was utilized for alpha autoradiography. Autoradiography by use of plastic film without nuclear emulsion has advantages; (1) simple procedures, (2) no darkroom needed, (3) a lower background obtainable, (4) little influence of temperature and moisture, (5) long standing material and so on. The disadvantage of this procedure is that tissue sections are easily damaged by strong alkalinity used for chemical etching. To solve this problem an overlapping histologic technique was worked out, permitting one to determine the relation of the heavy particle tracks to the intra and extracellular structures. Na2B12H11SH, a boron compound already in practical use, has been restudied by using this new technique. Autoradiograms showed favorable results with abundant alpha tracks over the tumor tissue in close relation to the cells and with very few tracks over the normal brain parenchyma. This technique is a useful means not only for further development of boron compounds but for other alpha emitters.

Animals↗

PubMed2002

[Properties of endoribonuclease activity of proteasomes from K562 cells. III. The specific endonuclease activity of ribonucleoprotein particles (alpha-RNP) tightly bound to chromatin and containing 20S proteosomes].

The present work demonstrates the ability of 20S proteasome-containing, tightly bound to chromatin RNP-particles (alpha-RNP) to endonucleolyse specific messenger RNAs (in particular, human mRNA for p53 gene and mRNA for luciferase from Renilla sp.). The dependence of individual mRNA endonucleolysis by alpha-RNP particles on both the substrate and enzyme was found.

Chromatin↗

PubMed2002

The radiation-induced bystander effect for clonogenic survival.

It has long been accepted that the radiation-induced heritable effects in mammalian cells are the result of direct DNA damage. Recent evidence, however, suggests that when a cell population is exposed to a low dose of alpha particles, biological effects occur in a larger proportion of cells than are estimated to have been traversed by alpha particles. Experiments involving the Columbia University microbeam, which allows a known fraction of cells to be traversed by a defined number of alpha particles, have demonstrated a bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. When 1 to 16 alpha particles were passed through the nuclei of 10% of a C3H 10T(1/2) cell population, more cells were unable to form colonies than were actually traversed by alpha particles. Both hit and non-hit cells contributed to the outcome of the experiments. The present work was undertaken to assess the bystander effect of radiation in only non-hit cells. For this purpose, Chinese hamster V79 cells transfected with hygromycin- or neomycin-resistance genes were used. V79 cells stably transfected with a hygromycin resistance gene and stained with a nuclear dye were irradiated with the charged-particle microbeam in the presence of neomycin-resistant cells. The biological effect was studied in the neomycin-resistant V79 cells after selective removal of the hit cells with geneticin treatment.

Alpha Particles↗

PubMed1997

[Possibility of alpha-tricalcium phosphate (alpha-TCP) particles as a drug carrier for treatment of abdominal carcinomatosis].

It is reported that cancer foci are unevenly distributed in abdominal carcinomatosis after intraperitoneal inoculation of cancer cells in rats. The organs may be briefly classified into two groups in terms of the deposit of cancer cells: one that shows an affinity to the cells includes the greater omentum, mesenterium, and gonadal fat and etc., and the other having lesser affinity the stomach, intestine, and spleen and etc. Such uneven distributions are likely to occur in clinical cases of abdominal carcinomatosis resulting from progressive digestive cancers. We have explored the possibility of alpha-Tricalcium Phosphate (alpha-TCP) particles as a drug carrier in which carboplatin (CBDCA) was incorporated. alpha-TCP, which has chemically similar properties to hydroxyapatite, is known to have an excellent biocompatibility with human tissues and is biodegradable. The present study focused on the localization and the forms of alpha-TCP particles, and the morphological changes of the surrounding tissues after intraperitoneal administration using normal and cancer-bearing rats. The following results were obtained: (1) alpha-TCP particles were taken up to a large extent in the "milky spot" of the greater omentum, followed by the "stomata" of the mesenterium, gonadal fat, diaphragm, peritoneum, and liver in normal rats. No alpha-TCP particles were caught up in the tissues of the stomach, small intestine, colon, and spleen. The margination and emigration of lymphocytes were slightly observed around those organs. (2) alpha-TCP particles were predominantly detected on the cancer mass of the greater omentum in abdominal carcinomatosis-bearing rats. It should be noted that the particles collected in the same place where cancer cells were caught, suggesting that the localization of the drug-containing particles result in higher drug concentrations in the cells possibly for extended times. The alpha-TCP particles system is expected to be a good candidate for targeting chemotherapy and specially for abdominal carcinomatosis.

Abdominal Neoplasms↗

PubMed1997

Biophysical analysis of the dose-dependent overdispersion and the restricted linear energy transfer dependence expressed in dicentric chromosome data from alpha-irradiated human lymphocytes.

Experimental data for the induction of dicentric chromosomes in phytohemagglutinin (PHA)-stimulated human T lymphocytes by 241Am alpha-particles obtained by Schmid et al. have been analyzed in the light of biophysical theory. As usual in experiments with alpha-particles, the relative variance of the intercellular distribution of the number of aberrations per cell exceeds unity, and the multiplicity of the aberrations per particle traversal through the cell is understood as the basic effect causing this overdispersion. However, the clearly expressed dose dependence of the relative variance differs from the dose-independent relative variance predicted by the multiplicity effect alone. Since such dose dependence is often observed in experiments with alpha-particles, protons, and high-energy neutrons, the interpretation of the overdispersion needs to be supplemented. In a new, more general statistical model, the distribution function of the number of aberrations is interpreted as resulting from the convolution of a Poisson distribution for the spontaneous aberrations with the overdispersed distributions for the aberrations caused by intratrack or intertrack lesion interaction, and the fluctuation of the cross-sectional area of the cellular chromatin must also be considered. Using a suitable mathematical formulation of the resulting dose-dependent over-dispersion, the mean number lambda 1 of the aberrations produced by a single particle traversal through the cell nucleus and the mean number lambda 2 of the aberrations per pairwise approach between two alpha-particle tracks could be estimated. Coefficient alpha of the dose-proportional yield component, when compared between 241Am alpha-particle irradiation and 137Cs gamma-ray exposure, is found to increase approximately in proportion to dose-mean restricted linear energy transfer, which indicates an underlying pairwise molecular lesion interaction on the nanometer scale.

Alpha Particles↗

PubMed1996

Formation Mechanism of Monodispersed alpha-Fe2O3 Particles in Dilute FeCl3 Solutions

Some ambiguity is still involved in the interpretation of the growth mechanism of monodispersed hematite (alpha-Fe2O3) particles in dilute FeCl3 solutions. Namely, there are two entirely different proposals on this issue, viz. aggregation of preformed primary particles of alpha-Fe2O3 itself and reprecipitation of the ionic species through dissolution of the preformed beta-FeOOH particles. In order to resolve this problem, the formation process was followed in detail through TEM, Electron Diffraction, XRD, FT-IR, and ICP spectrometry along with quantitative analyses on seed effects. As a result, it has been concluded that the nuclei of the hematite particles are initially generated with the formation of beta-FeOOH particles and that they are grown by deposition of the solute originally present in the solution phase and indirectly furnished from the beta-FeOOH by dissolution. As the concentration of the solute is lowered by the growth of the hematite particles, they continue to grow with the solute provided mainly from the beta-FeOOH in a steady-state of the dissolution of beta-FeOOH and growth of alpha-Fe2O3. The basic formation mechanism is common to the ellipsoidal particles grown in the presence of phosphate ions and spherical particles in their absence.

Journal Article↗

PubMed2005

Differential impact of mouse Rad9 deletion on ionizing radiation-induced bystander effects.

The cellular response to ionizing radiation is not limited to cells irradiated directly but can be demonstrated in neighboring "bystander" populations. The ability of mouse embryonic stem (ES) cells to express a bystander effect and the role of the radioresistance gene Rad9 were tested. Mouse ES cells differing in Rad9 status were exposed to broad-beam 125 keV/ microm 3He alpha particles. All populations, when confluent, demonstrated a dose-independent bystander effect with respect to cell killing, and the Rad9-/- genotype did not selectively alter that response or cell killing after direct exposure to this high-LET radiation. In contrast, relative to Rad9+/+ cells, the homozygous mutant was sensitive to direct exposure to alpha particles when in log phase, providing evidence of a role for Rad9 in repair of potentially lethal damage. Direct exposure to alpha particles induced an increase in the frequency of apoptosis and micronucleus formation, regardless of Rad9 status, although the null mutant showed high spontaneous levels of both end points. All populations demonstrated alpha-particle-induced bystander apoptosis, but that effect was most prominent in Rad9-/- cells. Minimal alpha-particle induction of micronuclei in bystander cells was observed, except for the Rad9-/- mutant, where a significant increase above background was detected. Therefore, the Rad9 null mutation selectively sensitizes mouse ES cells to spontaneous and high-LET radiation-induced bystander apoptosis and micronucleus formation, but it has much less impact on cell killing by direct or bystander alpha-particle exposure. Results are presented in the context of defining the function of Rad9 in the cellular response to radiation and its differential effects on individual bystander end points.

Alpha Particles↗

PubMedDate not supplied

[Dependence of "macroscopic fluctuations" from cosmophysical factors. Spatial anisotropy].

It was shown in experiments with collimators that the changes with time in the shape of histograms constructed from the measurements of the alpha-activity of 239Pu microsamples depend on the direction of the flow alpha-particles. If the flow of alpha-particles was directed to the Polar Star, the dependence of the probability of the realization of histograms of similar shape on time disappeared. The measurements of alpha-particle flows directed to the East and West revealed a high probability of the repeated realization of histograms of similar shape in 1436 min, i.e., in a sederal day. A comparison of "west" and "east" histograms showed a high probability of the realization of similar "west" histograms 718 min (half a sideral day) later than "east" histograms. The results suggest that the shape of histograms depends on the pattern of the starry sky and the space-time inhomogeneity corresponding to this pattern.

Plutonium↗

PubMed1998

Studies of bystander effects in human fibroblasts using a charged particle microbeam.

PURPOSE: To determine the role of cell-to-cell mediated effects in the response of cells to different radiations by using a charged particle microbeam capable of targeting individual cells with counted particles. MATERIALS AND METHODS: Primary human fibroblasts were irradiated conventionally with X-rays or alpha-particles and scored for the induction of micronucleated or apoptotic cell formation at various times after irradiation. Cells were also individually irradiated with helium-3 particles from a microbeam and the distribution of damaged cells between hit and non-hit cells scored. RESULTS: Conventionally exposed fibroblasts showed a dose-dependent production of micronucleated and apoptotic cells 3 days after irradiation for both X-rays and alpha-particles, with a high RBE value for alpha-particles at low doses. Targeting individual alpha-particles, using a microbeam, to four cells within a population produced more micronucleated and apoptotic cells than expected on the basis of a direct effect only. CONCLUSIONS: This study provides direct evidence for the production of transmissible, cell-to-cell effects between hit and non-hit cells individually exposed to charged particles.

Alpha Particles↗

PubMed1983

Radium and uranium concentrations in Georgia community water systems.

The first cycle of statewide radionuclide concentration measurements of public drinking water supplies was completed in accord with the Federal and Georgia Safe Drinking Water Acts. The recommended pattern of analysis is initial screening for gross alpha-particle activity, followed by measuring 226Ra if the gross alpha-particle activity is above 5 pCi/l. and then measuring 228Ra if the 226Ra concentration is above 3 pCi/l; and uranium analysis if the gross alpha-particle activity exceeds 15 pCi/l. Surface water supplies for more than 100,000 persons are analyzed for 3H and 90Sr and screened for gross beta-particle activity, with additional analytical requirements if the latter is above 50 pCi/l. Specified supplies downstream for nuclear facilities are analyzed for 3H, 90Sr and 131I, and further analyses are required if the gross beta-particle activity is above 15 pCi/l. More thorough screening was applied for 1400 public water supplies in Georgia, of which about 90% use groundwater. Radium concentrations exceeded the maximum contaminant level (MCL) of 5 pCi/l. in 24 groundwater supplies, mostly due to elevated 226Ra. The gross alpha-particle activity minus uranium concentrations exceeded the 15 pCi/l. MCL in 3 additional samples. No MCL was exceeded in surface water. The S.D.s of analytical results estimated from replicate analyses were approximately twice those based on counting statistics, suggesting that screening levels should be lowered to assure detection of 226Ra at MCL values.

Georgia↗

PubMed1996

[Intraperitoneal administration of carboplatin loaded alpha-tricalcium phosphate (alpha-TCP) particles in rats bearing abdominal carcinomatosis].

It is difficult to treat abdominal carcinomatosis with conventional chemotherapy, and many kinds of localized chemotherapy have been attempted. We used alpha-tricalcium phosphate (alpha-TCP) particles as a drug carrier in this study. alpha-TCP, which has chemically similar properties to human bone, has an excellent biocompatibility with human tissues and is biodegradable. The particles measured 50 to 100 microns in diameter, were round in shape and very porous. These particles have many open micro-pores of about 1 to 3 microns, which are beneficial for containing drugs. The compatibility and biodegradation of alpha-TCP particles were studied following intraperitoneal (ip) administration in normal rats. The following results were obtained: (1) alpha-TCP particles were intaken in the great omentum, and dissolved gradually. (2) The efficacy of ip administration of carboplatin-loaded alpha-TCP (alpha-TCP-CBDCA) was examined using a Donryu rat model with AH130 abdominal carcinomatosis. The alpha-TCP-CBDCA contained 200 mg alpha-TCP and 4 mg CBDCA. The pharmacokinetics of CBDCA following ip administration of alpha-TCP-CBDCA were studied. Pt levels in ascites and great omentum were higher in the alpha-TCP-CBDCA ip from 0.5 to 168 hours than those in the free-CBDCA ip and iv groups. These results suggest that the efficacy of CBDCA may be enhanced by utilizing alpha-TCP particles as a drug delivery carrier.

Animals↗

PubMed2005

The microdosimetry of boron neutron capture therapy in a randomised ellipsoidal cell geometry.

Two reactions deliver the majority of local dose in boron neutron capture therapy. The ionised particles (protons, alpha particles and lithium nuclei) produced in the two reactions, 10B(n,alpha,gamma)7Li and 14N(n,p)14O, have short ranges that are less than -14 microm (which is on the order of the diameter of a typical human cell). The ionised particles are heavy and are in the 2+ charge state in the case of the boron reactions. These heavy 2+ ions will do significant damage to molecules near their tracks. Thus, the distribution of nitrogen and, in particular, of boron determines the spatial characteristics of the radiation field. Since the distribution of nitrogen is nearly homogeneous in the brain and is not easily altered for the purpose of radiotherapy, the spatial variation in the radiation dose is due mainly to the spatial distribution of boron. This implies that the spatial distribution of boron determines the microscopic energy deposition and therefore the spatial characteristics of the microscopic dose. The microscopic dose from the (n,alpha) and (n,p) reactions has been examined in detail and, as averred, the proton dose is relatively homogeneous except for statistical variability. The statistical variability in essence adds a false spatial variability that would not be seen if a large number of histories were performed. Since the majority of spatial variability occurs in the boron distribution, the (n,p) reaction can be suppressed to better understand the spatial distribution effects on the microscopic dose. Programs have been written in FORTRAN using Monte Carlo techniques to model ellipsoidal cells that are either randomly sized and located in the region of interest or are arranged in a face centred cubic array and are identical except for the location of the nuclei, which may be random. It is shown that closely packed prolate ellipsoidal cells with a large eccentricity in one dimension will receive a larger nuclear dose than cells that are more sparsely packed. This demonstrates that the boron content of a cell and its nucleus can have a significant impact upon the dose to neighbouring cells. The local boron distribution in a region of interest can be shown to affect the macrodosimetric dose, with possible implications for clinical outcomes.

Animals↗

PubMed2003

Absorbed fraction of radon progeny in human bronchial airways with bifurcation geometry.

PURPOSE: The absorbed fraction, defined as the portion of the initial particle energy which is absorbed in the tissue of interest, was calculated, under bifurcation geometry of the airway tubes, for alpha-particles emitted from radon progeny in the human respiratory tract. The results are given for all branching generations and compared with the data obtained for the commonly used infinite straight cylinders adopted by the International Commission on Radiological Protection (ICRP) Report 66. MATERIALS AND METHODS: A model was created to calculate the absorbed fraction of alpha-particle energy in the human lung using bifurcation geometry. Monte Carlo simulations of alpha-particle propagation in tissue and air were performed. The stopping powers of alpha-particles were adopted from the International Commission of Radiation Units and Measurements (ICRU) Report 49. RESULTS: The absorbed fractions for the bifurcation geometry are given for the 15 generations in the tracheobronchial tree for alpha-particle energies of 6 and 7.69 MeV. The sources were assumed to be the fast and slow moving mucus. CONCLUSIONS: Comparisons with ICRP66 data reveal that the assumption of long, straight cylinders was appropriate in some cases, but not in all. Adoption of the absorbed fractions obtained from the bifurcation model instead of the ICRP66 data caused 'redistribution' of doses in the bronchial (BB) and bronchiolar (bb) regions.

Bronchi↗

PubMed1996

5-[211 At]astato-2'-deoxyuridine, an alpha particle-emitting endoradiotherapeutic agent undergoing DNA incorporation.

When labeled with the subcellular range Auger electron emitters 125I and 123I, the thymidine analogue 5-iodo-2'deoxyuridine (IUdR) is highly cytotoxic but only to cells going through S-phase during exposure to these radiopharmaceuticals. Since 211 At emits alpha-particles of high linear energy transfer, but with a range of a few cell diameters, an IUdR analogue labeled with 211At could markedly improve the homogeneity of tumor dose deposition. Herein we describe the synthesis of 5-[211 At]astato-2'-deoxyuridine ([211 At]AUdR) in 85-90% radiochemical yield via the astatodestannylation of 5-(trimethylstannyl)-2'-deoxyuridine. In vitro studies using the human glioma cell line D-247 MG demonstrated that [211 At]AUdR was virtually identical to [131I]IUdr; both exhibited a linear increase in cell uptake with activity concentration, an inhibition of uptake by 10 micrometers IUdR, and the incorporation of about 50% of cell-bound activity into DNA. In a clonogenic assay, [211 At]AUdR exhibited a high cytotoxicity for D-247 MG cells, with a D(0) equivalent to less than 3 211At atoms/cell.

Brain Neoplasms↗

PubMed2006

Biodegradation process of alpha-TCP particles and new bone formation in a rabbit cranial defect model.

The purpose of the present study was to observe the biodegradation process of pure alpha-tricalcium phosphate (alpha-TCP) particles and to determine the efficacy of alpha-TCP as a space maintainer in a bone defect. We used 14 rabbits and prepared two cranial bone defects in each rabbit. One defect was left empty as a control, whereas the other was filled with alpha-TCP particles about 300 mum in diameter. Animals were sacrificed at 1 week, 4 weeks, and 8 weeks. The cranial bone was then embedded either in paraffin wax for the preparation of decalcified specimens, or in polyester resin for the preparation of nondecalcified specimens. All specimens were evaluated histologically and histomorphometrically. As a consequence of the degradation of alpha-TCP, a "reticulate structure" appeared in the particles at 1 week and new bone was observed in this structure at 8 weeks. The amount of new bone between the control and experimental groups was not significantly different at any of the time points. However, in the experimental group, new bone at the surface of alpha-TCP was evident even in the center of the defect whereas fibrous connective tissue was dominant in the control group. These results indicate that alpha-TCP is a degradable osteoconductive material that is able to act as a space maintainer for bone regeneration when applied to a bone defect. While there was no significant difference in total bone formation between the experimental and negative control groups, the space-maintaining and osteoconductive properties of the particles may result in more complete bone formation in longer-term studies.

Absorbable Implants↗

PubMed2003

[Effect of surface decoration on the spectral characteristics of alpha-Fe2O3 ultrafine particles].

The alpha-Fe2O3 ultrafine particles were equally dispersed in the solutions of stearic acid/n-hexane/chloroform by the ultrasonic method, the surfaces of the alpha-Fe2O3 ultrafine particles were decorated by stearic acid, and the alpha-Fe2O3 ultrafine particles decorated had very good flowage characteristic. Before alpha-Fe2O3 ultrafine particles were decorated, the UV absorption was very strong at wavelengths shorter than 290 nm, and there was a shoulder peak at 330 nm. The absorption band edges of alpha-Fe2O3 ultrafine particles was at 392 nm, and shifted toward blue, which was in contrast with that of bulk Fe2O3. This was caused by the quanta size effect and surface effect. IR characteristic peaks of the alpha-Fe2O3 ultrafine particles appeared at 524.36 and 446.37 cm-1. After alpha-Fe2O3 ultrafine particles were decorated, the absorption side moved from 392 to 896 nm, which significantly shifted to the red in contrast with that of bulk F2O3. The vibration of Fe-O bond moved from 524.36 to 521.33 cm-1 and from 446.37 to 443.34 cm-1, respectively. These were caused by the dielectric confinement effect. The relative intensity of X-ray diffraction obviously increased, and the diffraction peak size moved toward the direction of smaller diffraction angle after the alpha-Fe2O3 ultrafine particles were decorated.

Chloroform↗