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A 63-year-old woman presented with radionecrosis in the bilateral temporal lobes manifesting as dementia about 30 years after undergoing conventional radiotherapy for pituitary adenoma. Computed tomography and magnetic resonance (MR) imaging showed edema and cystic lesions in both temporal lobes. The mass in the left temporal lobe was excised. MR imaging 12 days after surgery showed reduced edema. Her dementia had improved. Radionecrosis usually occurs between several months and a few years after radiotherapy. The incidence of radionecrosis is estimated as 5%, but may be higher with longer follow-up periods. Clinical reports have suggested that larger total doses of radiation are associated with earlier onset of delayed necrosis and the fractional dose is the most significant factor causing cerebral radionecrosis. Radionecrosis can occur long after conventional radiotherapy or stereotactic radiosurgery using a linac-based system or a gamma knife unit.

Over the last few years, a conditionally replicating herpes simplex virus 1 (HSV-1) vector, G207 has been used for the treatment of several malignant tumors. In this article we evaluate the anti-tumoral effect of G207 against prostate cancer in vitro and in vivo. The susceptibility of the human prostate cancer cell lines, DU145 and PC3 to G207 at a multiplicity of infection (MOI) of 0.1 was examined. In addition, the growth characteristics of G207 were assessed. Athymic mice with s.c. tumors were inoculated in vivo intraneoplastically with 1 x 10(7) plaque-forming units (PFU) of G207. For the pathological analyses, s.c. tumors were stained with X-gal. DU145 and PC3 were efficiently destroyed by G207 within 7 days. The viral yields of G207 increased time-dependently. In vivo, the intraneoplastic inoculation of G207 induced a significant inhibition of the tumor growth. The mean tumor growth ratio was significantly inhibited in the G207-treated tumors (DU145, P < 0.0001; PC3, P < 0.001 versus controls). In a pathological study, many lacZ-positive cells were diffusely present in the G207-treated tumors. G207 showed a significant antitumoral effect against human prostate cancer cell lines, and thus may be considered a useful agent for the treatment of prostate cancer.

Two patients presented with hypoglossal neurinoma extending both intra- and extracranially. A 63-year-old male presented with right trigeminal neuralgia and hypoglossal nerve paresis. The intracranial part of the tumor was removed totally via a suboccipital craniectomy. Over-coagulation of the venous collaterals, particularly the emissary veins, resulted in dural venous sinus thrombosis and cerebellar infarction. Unfortunately this patient died. A 48-year-old male presented with pareses of the VII, IX, X, XI, and XII cranial nerves and cerebellar sign. The tumor extended both extra- and intracranially, and was completely removed by opening the hypoglossal canal and the jugular foramen without over-coagulation of the venous collaterals. Preservation of the venous collaterals is very important for the prevention of postoperative venous complications.

The application of stable isotope analysis using neutron-induced prompt γ-ray analysis (PGA) with cold/thermal neutron beams for the tracer study of geological materials are discussed. Silicon has three natural isotopes differing in abundance:28Si (92.23%),29Si (4.67%) and30Si (3.10%). For the purpose of the assessment of Si migration in engineered barrier material, enriched30Si can be used as a tracer due to its nuclear and chemical properties. Isotope analysis of30Si was performed by PGA during the tracer study. Neutron intensity at the sample position was 1.4·108 n¢cm−2·s−1, 2.4·107 n·cm−2·s−1 for cold and themal neutron guided beams of JRR-3M, respectively. Calibration curves and analytical sensitivity of30Si were determined based on measurement of standard samples. BG and detection limits for30Si analysis were also measured in Japanese bentonite (Kunigel V1 and Kunipia F) and their pore water. Fiffteen elements were determined simultaneously using PGA.

Non-destructive multi-element determination in environmental samples by neutron-induced prompt γ-ray analysis (PGA) has been investigated. Comparative standardization for the elements including H, B, C, N, Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, Mn, Fe, Co, Cd, Sm, Gd, Hg by PGA has been carried out using the cold and thermal guided neutron beams of JRR-3M reactor and then several environmental reference materials have been analyzed. Accuracy and precision of better than 20% were found for these elemental analyses except for H, C, N and Cl in biological samples. Detection limits in various environmental matrices were 25 to 820 ng/g for B, Cd, Sm and Gd, 1.1 to 820 μg/g for H, Na, S, Cl, K, Ti, Mn, Co and Hg, and 0.031 to 10% for C, N, Mg, Al, Si, P, Ca and Fe. The present method is being applied to environmental studies of post war Persian Gulf together with INAA and ICP-MS.

A permanent and stand-alone neutron-induced prompt γ-ray analysis (PGA) system, usable at both cold and thermal neutron beam guides of JRR-3M has been constructed. The characteristics of the system, including neutron beam and γ-ray spectrometer were measured. Owing to the absence of fast neutrons and the low γ-ray background, analytical sensitivities and detection limits better than those in other PGA systems have been achieved. Analytical results of ten elements in Standard Reference Material of Coal Fly Ash agreed well with those obtained by other methods. Isotopic analysis of Ni and its application to accurate and precise determination of Ni by stable isotope dilution method were performed.

A reactor-neutron-induced prompt γ-ray analyzing system was constructed at JRR-3M. The system can be set at cold and thermal neutron beam guides with a neutron flux at the sample position of 1.1 × 10 8 and 2.4 × 10 7 n cm −2 s −1 , respectively. The system was designed to achieve the lowest γ-ray background. This is done by using lithium fluoride tiles as neutron shielding, by placing the samples in a He atmosphere, and by using a Ge-BGO detector system for Compton suppression. The γ-ray spectrometer is equipped to acquire three modes of spectra simultaneously: single mode, Compton suppression mode, and pair mode in an energy range of up to 12 MeV. Due to the cold neutron guide beam and the low background system, sensitivities and detection limits better than those in other PGA systems have been achieved. For typical elements such as H, B, Cd, and Gd, analytical sensitivities with the cold neutrons are 10 to 18 times higher, and detection limits are lowered by factor of 6 to 8, compared to the case with thermal neutrons under the same geometrical condition. Detection limits down to a range of 2 to 7 ng were recorded for B, Cd, Sm, and Gd by the cold neutrons. Hydrogen, one of the most important elements in material studies, could be detected down to 1.0 and 2.8 μg by cold and thermal neutrons, respectively.

がん診断前に採血された血清試料について,セレン及び亜鉛濃度と,その後の発がんリスクとの関連を疫学的に明らかにするため,セリウムを内標準とする機器中性子放射化分析法(INAA)による,少量(0.2ml以下)のヒト血清中のセレンと亜鉛の同時定量法を確立した.方法の概要は以下のとおりである.一定量のセリウム標準溶液を添加した血清試料と比較標準溶液を合成石英管にとり,試料は凍結乾燥後減圧封人し,比較標準はそのまま減圧封人し,JRR-2(熱中性子束2.2×1013n cm-2s-1以上)で265.5時間照射をする.約1か月間冷却後,石英管表面をフッ化水素酸で約5μmエッチングし,Ge(Li)検出器で一定時間(4000秒以下)γ線スペクトルを測定する.試料及び比較標準試料の141Ceに対する75Seと65ZRのγ線ピーク面積比から試料中のセレン及び亜鉛含量を算出する.同一試料14個による定量値のRSDは3.0%(Se)及び5.2%(Zn)であった.本法による血清試料及びNISTBovinc Liver標準試料(SRM1577,SRMI577a)の定量値は,NISTの保証値を含む他の方法による定量値と,極めてよく一致することが確認された.

Boron concentration of plasma, feces, urine and body tissues from sheep fed with borated water (100 mg B/l) and tap water were determined by neutron-induced prompt gamma-ray analysis to elucidate boron metabolism. The B level in plasma and urine increased rapidly and the B content of feces increased greatly. The B concentrations in body tissues (liver, kidney, spleen, thyroid and muscle) of B dosed sheep were ten times higher than those of tap water administered sheep.

機器中性子放射化分析(INAA)で,長時間照射の試料容器材として使用する石英管のから試験値に関する検討を行った.から試験値の要因である,1)石英管中の不純物,2)照射前及び照射中の汚染に関してINAAにより調べた.石英管中の不純物の分布を測定し,洗浄及びエッチング法の検討を行うと共に,製造方法の異なる各種石英管中の不純物の定量により,INAA用として最適の石英管を選定した.照射カプセル材及び包装材のAl中の不純物Uの核分裂生成物の汚染及び石英ガラス細工による加工の際のガスバーナーからの汚染についても調べ,その防止策を検討した.確立した方法によるNBS生体標準試料,Bovine Liver及びOrchard Leaves各々0.1gの分析における各種元素のから試験値は,標準試料中の存在量に比べ,Crを除き1%以下であった.Crは石英管中の含量のばらつきが他の元素に比べ大きく,Bovine Liver 0.1gの分析におけるから試験値の最大値は,1.8%であった.

A 63-year-old woman presented with radionecrosis in the bilateral temporal lobes manifesting as dementia about 30 years after undergoing conventional radiotherapy for pituitary adenoma. Computed tomography and magnetic resonance (MR) imaging showed edema and cystic lesions in both temporal lobes. The mass in the left temporal lobe was excised. MR imaging 12 days after surgery showed reduced edema. Her dementia had improved. Radionecrosis usually occurs between several months and a few years after radiotherapy. The incidence of radionecrosis is estimated as 5%, but may be higher with longer follow-up periods. Clinical reports have suggested that larger total doses of radiation are associated with earlier onset of delayed necrosis and the fractional dose is the most significant factor causing cerebral radionecrosis. Radionecrosis can occur long after conventional radiotherapy or stereotactic radiosurgery using a linac-based system or a gamma knife unit.

In the fission system 244Pu + p, formation cross sections of rare earth products were observed in the proton energy range 10 to 16 MeV, and their angular distributions were measured in detail of proton energy of 15 MeV. The highest mass number of rare earth products was 162 which corresponded to a highly asymmetric mass division of AH/AL ≈ 2. The incident energy dependence and angular anisotropies of rare earth products were found to be the same, even for highly asymmetric mass division, and no clear evidence was observed for the effect of neutron numbers 50 and 97 on cross section and angular anisotropy. These observations lead to the conclusion that the fission process, leading to highly asymmetric mass division, experiences the same saddle point in the course of deformation toward scission as that for other typical asymmetric mass division.

Herpes vector has been widely used for experimental gene therapy. We herein review the strategies of such therapy for the treatment of urologic neoplasms. Most experimental studies of genetically altered viruses have employed replication-incompetent vectors. However, such viruses are unable to infect additional cells subsequent to the initial infection event. Therefore, this strategy has relied heavily on the bystander effect because a large number of noninfected tumor cells remain. Conditionally replicating herpes vector G207 has been developed in order to overcome potential problems of safety and tumor specificity for human use. It has been used to treat malignant brain tumors because of its neural tropism. In the last few years, applications of G207 for non-neural tumors have been reported. Because G207 may be useful for the treatment of urologic malignant tumors, we evaluated the antitumor effect against several types of tumor cells both in vitro and in vivo. Our data suggest that G207 may be applicable for the treatment of urologic malignant tumors.

The extraction of americium(III) and thorium(IV) by thenoyltrifluoroacetone (TTA) and dibenzoylmethane (DBM) and the adsorption of the ions on silica gel were studied so as to develop a method for the separation of plutonium(III) and plutonium(IV) in natural waters. When the aqueous phase was free from strong complexing anions, the separation of americium(III) and thorium(IV) was possible by the TTA and DBM extraction methods in the pH ranges 1–2.5 and 3–6 respectively and they were roughly separated by the silica gel adsorption method. However, 0.03 M sulphate solution interfered with the separation by the adsorption method and shifted the suitable pH range for the separation by solvent extraction. Fluoride ion may also affect the extraction and adsorption, judging from its complex formation constant with actinoid(IV). The concentrations of complexing anions should be considered for the separation of actinoid(III) and actinoid(IV) in natural waters.

Surgical removal remains the only potentially curative therapy for renal cell carcinoma. In this study we evaluated the inhibitory effect of the replication competent engineered herpes simplex virus type 1, G207, for renal cell carcinoma in vitro and in vivo.The nature of G207 enables it to replicate within cancer cells, thus, causing cytolysis, but replication is restricted within normal cells. The susceptibility of the human renal cancer cell lines ACHN and A498 to G207 at a multiplicity of infection of 0.1 was examined. In addition, the growth characteristics of G207 was assessed. In vivo athymic mice bearing subcutaneous tumors were inoculated with 1 x 10(7) plaque forming units of G207 intra-neoplastically. For pathological analysis subcutaneous tumors were stained with X-gal.Two cell lines were efficiently destroyed by G207 within 1 week. The viral yields of G207 increased in a time dependent manner. In vivo the intra-neoplastic inoculation of G207 caused significantly decreased tumor growth in athymic mice harboring subcutaneous human renal cancer cells. On day 14 the mean growth ratio of ACHN and A498 lesions was significantly inhibited in G207 treated compared to control tumors (p0.005 and0.0001, respectively).These results suggest that G207 should be considered another potential therapeutic agent for renal cell carcinoma.

G207, a conditionally replicating herpes vector, efficiently kills human bladder cancer cells in vitro. To evaluate the therapeutic potential of G207, we have established three in vivo models similar to the clinical situation. In vivo, G207 was intraneoplastically, intravesically, or intravenously inoculated in nude mice. Intraneoplastic inoculation into subcutaneous tumor caused significant tumor growth inhibition. Intravesical inoculation of G207 also caused decreased tumor growth in an orthotopic human bladder cancer model. Furthermore, multiple intravenous inoculation markedly inhibited subcutaneous tumor growth. These results suggest that intravesical therapy with G207 is effective for localized bladder tumor, especially for carcinoma in situ (CIS), and intravenous therapy with G207 is promising for invasive or metastasized bladder tumor.

We set up experiments to evaluate the effects of defective herpes simplex virus (HSV)-mediated in vitro gene transfer of tissue inhibitor of metalloproteinases-2 (TIMP-2) in malignant glioma cells. Intrinsic TIMPs are known to be inhibitors of the strong invasive activities of matrix metalloproteinases in malignant gliomas. The defective HSV vectors dvSRaTIMP2 was engineered to express human TIMP-2 (hTIMP-2) with a combination of replication-competent HSV mutant, temperature-sensitive HSV-tsK, and amplicon plasmid-containing hTIMP-2. The hTIMP-2 gene was driven by the simian virus 40 promoter. The helper virus (HSV-tsK) was thermosensitive; consequently, this vector could proliferate only at 31.5 degrees C. After infection of U87 human glioblastoma cells with the vector in vitro, expression of TIMP-2 was confirmed by reverse zymography. The U87 cells infected in vitro either with dvSRaTIMP2 or HSV-tsK were efficiently destroyed under replication-permissive conditions (at 31.5 degrees C) and significantly lowered under replication-nonpermissive conditions (at 37 degrees C). The invasive activity of U87 was clearly inhibited by dvSRaTIMP2 infection at both 31.5 degrees C and 37 degrees C. Our studies suggest that TIMP-2 expressing the defective HSV vector is possibly useful for the treatment of malignant brain tumors.

To obtain fundamental data on the application of neutron-induced prompt gamma ray analysis (PGA) to agricultural research, we determined concentration of boron (B) in plant and soil materials with the PGA system, using thermal and cold neutron beam guides. Concentration of B was determined by the calibration curve method and the standard addition method. Boron in plant and soil reference materials was determined quantitatively, exhibiting an accuracy rate better than ± 13.5%, and a precision rate better than 11.6%. The detection limit for the plant reference material was 0.18~0.55 μ g g-1 using cold neutron irradiation (300~4000 s-measurement) and 0.59~0.99 μ g g-1 using thermal neutron irradiation (2000~6000 s-measurement). That for the soil materials was 0.59~0.97 μ g g-1 using thermal neutron irradiation (2000~6000 s-measurement).

Although low-grade astrocytomas are histologically benign, some of them recur frequently. We retrospectively investigated the relationship between MIB-1 staining index (SI) and recurrence in 47 low-grade astrocytomas that were treated in Keio University Hospital from 1981 to 1991. We found a correlation between SI and recurrence. MIB-1 SIs recurrent low-grade astrocytomas have been shown to be almost similar to those of astrocytoma grade 3. We concluded that it was very important to examine MIB-1 SI in all astrocytomas especially in low-grade astrocytomas, because MIB-1 SI is one of the factors from which we could predict recurrence and decide whether radiotherapy or chemotherapy should be performed.

Twenty-six brain tumor patients have been treated with the boron neutron capture therapy (BNCT) at the JRR-2, Japan Atomic Energy Research Institute (JAERI)1, since 1990. An accurate analysis of ppm levels of 10B content in tissues is essential for determining neutron irradiation dose in the BNCT. Although the ppm level of 10B can be analyzed by destructive analytical methods of inductively coupled plasma atomic emission spectrometry (ICP-AES) and spectrophotometry, due to the necessity of sample decomposition, these methods are not suitable when quick analysis is required for determining the neutron irradiation dose before the BNCT treatment. A neutron-induced prompt γ-ray analysis (PGA)2 is characterized by the capability of nondestructive 10B analysis. On account of large cross section of the reaction 10B(n,α)7*Li (σ = 3837 barn), the Doppler broadened 478 keV photo-peak is observed with the highest sensitivity by the PGA. The 10B in the tissues was determined by measuring the 478 keV peak area against the 2223 keV peak area for the 1H as an internal standard3,4.

A piece of stainless steel 304 was thermal annealed either in a 60 Co solution at 280°C, or in a He atmosphere at 300 or 600°C after being smeared with a 60 Co solution. The depth profile of 60 Co in SUS was determined with these samples, together with those sampled from the water cleaning system in the Japan Power Demonstration Reactor and those exposed to a high-temperature water ( ~ 280°C) circulating OWL-loop installed in the Japan Material Testing Reactor, in order to determine the apparent values of the volume and grain boundary diffusion constants. The results have been compared with those of the previous measurements on Ni, Cr, and Fe above 500°C. A consistency has been noticed between both results at 600°C, while the present values at 280 and 300°C are much larger than those expected from the extrapolation of the previous measurements. Although this inconsistency is ascribed to the contribution of the dislocation pipe diffusion at such a low temperature, an attempt has been made to apply the present values to estimate how deep 60 Co would penetrate SUS—one of the main constructing materials of the primary cooling system—in the life time of a power reactor.

The precipitations of thorium and uranium(VI) sulfito complex ions with hexammine cobalt(III) chloride as the precipitant have been studied. The orange-colored uranium(VI) precipitate obtained is [Co(NH3)6]4[UO2(SO3)3]322H2O, which is in the form of square bipyramid, about 4 μm across in a cubic symmetry of the diamond type with a=10.40A It decomposes to an oxide mixture of Co3O4 and U3O8 above 850°C in the air through a sulfate mixture of CoSo4 and UO2SO4. Composition of the thorium precipitate varies with the precipitation conditions. Therefore, it is considered that the thorium precipitate contains thorium hydroxide and basic thorium sulfite.

半導体メモリー構成材料中のppb以下の含量のUとThを定量するため,テノイルトリフルオロアセトン(TTA)液-液抽出分離法を用いたNAAを検討し,Al及びMg試料の分析に適用した.試料を原子炉で照射後1M塩酸溶液とし,生成した239Np(IV)と233Pa(V)をTTA-キシレン溶液で抽出する.10M硝酸で239Npを,5M硫酸で233Paを逆抽出する.試料と同時に照射したUとTh比較標準溶液についても試料と同様に操作し,γ線スペクトロメトリーにより239Npと233Paを測定し,UとThを定量する.239Npと233Paの回収率は90%以上であった.岩石標準試料(JB-1, JG-1)の分析により,本法の正確さを確認し,Al及びMg試料(50～100mg)中の0.5PPb以上のUとThを定量した.

Sample specimens of type 304 stainless steel and Zircaloy-2 were exposed to the OWL-1 loop water at 280°C for 23d. After the exposure, a number of crystallites are distributed either separately or sometimes in agglomerate on the surfaces. The X-ray diffraction analysis and XMA analysis of the type 304 stainless steel surface revealed that more than 95% of the crystallites have a M2O3-type of structure, and some are enriched in Cr. In the sub-sequent radiochemical analysis of the fractions detached by the various cleaning processes (ultrasonic, electrostripping and electropolishing), it is noticed that the 60Co/Co ratio decreases with the depth of the corrosion layer from the value close to that of insoluble crud in the water (crud-P) to that of soluble crud (crud-F).

For the determination of specific activity of63Ni, a method has been developed for simultaneous assessment of both stable and radionickel. The method comprises solvent extraction of Ni-dimethylglyoxime into xylene for spectroscopic measurement and liquid scintillation counting of the extractant. The application of the method has been successful for63Ni in the corrosion products accumulated on the wall surface in the primary circuiting tube of the reactor.

A method for determining the macroscopic amount of iron and its radioactivity (/sup 55/Fe) in radioactive corrosion products was established with a single chemical procedure. The iron was first extracted into a liquid scintillator (2,5-diphenyloxazole-xylene) as an ion associate of iron bathophenanthroline (BPT) complex and perchlorate at pH 3-8, followed by measurement of its radioactivity by a liquid scintillation counter and its absorbance by a spectrophotometer. The absorption maximum and molar absorptivity (epsilon) of the complex were 535 nm and 22,000, respectively. The system conforms to Beer's law at concentrations of up to 30 ..mu..g of iron in 10 mL of organic phase. The counting efficiency of the extracted /sup 55/Fe was found to be 60%. Although /sup 60/Co is extracted into the PPO-xylene together with /sup 5/)2%Fe, it is separated from /sup 55/Fe by back extraction with 0.005 M ethylenediaminetetraacetic acid (pH 6.0) into the aqueous phase. The effects of other foreign elements and radionuclides were also examined. The proposed method was successfully applied to analysis of radioactive corrosion products. 21 references, 6 figures, 3 tables.

Corrosion behavior of SUS-304 at 280/sup 0/C in deaerated water has been traced both through measuring H/sub 2/ gas, concomitantly formed with corrosion, and through radiochemical analysis of the corrosion layers. The calculated H/sub 2/ yield based on the reaction, M + x.H/sub 2/O = MO /sub x/ + x.H/sub 2/ (M: iron, chromium, nickel, manganese, and cobalt), agreed reasonably well with the observed H/sub 2/ yields, showing that iron is mainly in a magnetite form and chromium is in a Cr(III) state. More than 85% of the corrosion layers were recovered by repeating ultrasonic cleaning and electrostripping processes. The residual fraction was rich in chromium and dissolved in the subsequent electropolishing process. The total corrosion increases with the reaction time, although the ''inner layer'' tends to stay almost constant at a longer reaction time. In some cases, both neutron irradiated and nonirradiated SUS coexisted. Mutual transfer of the elements from one SUS to the other has been examined.

The distribution ratios, Kd, for zirconium and hafnium were measured in the hydrochloric acid-TBP-celite system, the acid concentration being varied from 5 N to 8 N. The data obtained showed that the separation factor for the above elements, Kdzr⁄KdHf, is fairly high, –4, in the 7–8 N hydrochloric acid range. Thus, the separation of these elements was carried out in 7.1 N hydrochloric acid by the use of a TBP-celite column.

The precipitation behaviors of uranium(VI) peroxo complex ion have been investigated with hexammine cobalt(III) cation. This precipitation reaction produces [Co(NH3)6]4[(UO2)2(O2)4]3 nH2O, which changes to monoperoxo species by hydrolysis in water. Monoperoxo species i.e. [Co(NH3)6]4[(UO2)2(O2)2(OH)4]312H2O belongs to a tetragonal system with a = 7·18 A and c = 13·02 A .

The precipitation behavior of thorium, uranium(IV) and plutonium(IV) in an ammonium oxylate solution with hexaurea chromium(III) ion was studied. Grayish green colored precipitate was produced in the case of thorium(IV), and green colored precipitates were produced in the case of uranium(IV) and plutonium(IV), respectively. The compositions of the thorium, uranium(IV) and plutonium(IV) compounds were, [Cr(CON2-H4)6[Th(C2O4)5]·5H2O, [Cr(CON2H4)6[U(C2O4)5]·5H2O and [Cr(CON2H4)6]4[Pu(C2O4)4]3·nH2O, respectively. Chemical and crystallographic properties of these compounds were also studied.

It is well known that the 235U content in uranium can be determined by comparing γ-activities from 235U and those from 234Th and 234m, 234Pa formed by the disintegration of 238U and in the radiochemical equilibria. Although this method looks convenient, it is not utilized widely, because about 8 months are necessary for attaining the equilibria after any chemical separation of uranium and thorium. In the present work, the above γ-spectrometric method was extended to uranium samples in which the equilibria are not yet attained. The proposed method determines 0.41% 235U at about 20 days after the purification of uranium from thorium. Values obtained agree well with those by the mass-spectrometry.

The crystalline compounds {[Co(NH 3 ) 6 ]HSO 4 } 2 [NpO 2 (SO 4 ) 3 ]. n H 2 O and {[Co(NH 3 ) 6 ] HSO 4 } 2 [AmO 2 (SO 4 ) 3 ] · n H 2 O were prepared by addition of hexammine cobalt(III) ion to an aqueous solution of M O 2 2+ . They are isostructural with {[Co(NH 3 ) 6 ]HSO 4 } 2 [UO 2 (SO 4 ) 3 ]·5H 2 O: c symmetry of the diamond type, with lattice constant a = 10·74 A for both neptunium and americium compounds. Absorption spectra for neptunium(VI), plutonium(VI) and americium(VI) compounds in dilute sodium carbonate solution are also presented.

A substoichiometric extraction method with nitroso-R salt (NRS) has been studied for the determination of trace Co in crud. The Co-NRS complex is extracted substoichiometrically into Capriquat-CHCl3 at pH 6.5-9.0 in 20 min of shaking time. The analytical results obtained by the method are within 3% of relative error in the determination range of 5 to 50 micrograms. The proposed method is simple and has sensitivity of 0.5 micrograms, though Fe(II), Ni(II) and Cu(II) seriously interfere. The results applied for the determination of trace Co in crud are described.

The precipitation behavior of thorium, neptunium(V), plutonium(IV) and americium(III) in ammonium carbonate solution with hexammine cobalt(III) chloride was studied. Orange and green-yellow precipitates were produced in the case of thorium and plutonium(IV), respectively, while no precipitate of americium(III) was observed under the same conditions. On the other hand, neptunium(V) was precipitated as a white compound in ammonium carbonate solution before hexammine cobalt(III) chloride was added. The composition of the thorium and plutonium(IV) compounds were dihexammine cobalt(III) thorium pentacarbonate aquo trihydrate, [Co(NH3)6]2[Th(CO3)5·H2O]·3H2O, and dihexammine cobalt(III) plutonium(IV) pentacarbonate aquo tetrahydrate, [Co(NH3)6]2[Pu(CO3)5·H2O.]·4H2O. Chemical and crystallographic properties of the two compounds and crystallographic property of the uranium(VI) compound were also studied.