The Chemistry of Americium. I : A Study of the Preparation of Am(V) and Its Behavior by Means of TTA Extraction

The method for preparing Am(V) in various solutions was investigated by utilizing the difference in extractability between Am(V) and Am(III) in an TTA-isobutanol extraction system ; Am(III) was quantitatively extracted with 0.1 M TTA in isobutanol from a 1 M acetate buffer solution at a pH greater than 3, while the percentage of Am(V) extracted into the organic phase was increased substantially with an increase in the pH from 3 to 5. When the organic phase containing Am (V) was shaken with an aqueous phase having a proper pH value and composition, Am(V) was selectively stripped into the aqueous phase. The stability of the valency state of Am(V) in the perchlorate, the acetate, and the sulfate solutions was then studied by examining the variation in the percentage of americium extracted as a function of the standing time. The rate of change in the valency state in the acetate and the perchlorate media is very slow, while it is rather rapid in the sulfate medium. This difference may be attributable to the faster rate of the disproportionation reaction of Am(V) in the last medium than in the former two. By applying the above results, the chemical behavior of Am(V) in the aqueous solution was investigated by TTA extraction ; it was found that Am(V) would be in the form of AmO_2^+ in the absence of a complexing reagent. By the addition of acetate ions, the step-by-step formation of the acetate complex of Am(V) was observed. The stability constants of [AmO_2Ac] and [AmO_2Ac_2]^- were determined to be (25.0±3.1) (mol/l)^ and (12.8±1.2) (mol/l)^ respectively

A Systematic Calculation of Nuclear Yields at the Production of Transuranium Elements by Multi-step Neutron Irradiation in a Reactor

A general procedure, which is amenable to computer programming, is developed for the evaluation of nuclear yields at the production of transuranium elements by multi-step neutron irradiation in a reactor. Chain members in nuclear transformation chains are progressively chosen, and chain member yields are systematically calculated. All reaction chains that start from nuclides produced at the preceded step are traced, and nuclear yields are obtained by the separate summation of chain member yields ; they are then used as initial nuclear yields at the next step. When these treatments are continued till the last step, final nuclear yields are obtained. The yields of fission product nuclides can be also evaluated by the developed procedure without any modification

NOS2 polymorphisms associated with the susceptibility to pulmonary arterial hypertension with systemic sclerosis: contribution to the transcriptional activity

Systemic sclerosis (SSc) is a connective tissue disease characterized by tissue fibrosis. One of several complications of SSc, pulmonary arterial hypertension (PAH) can be refractory to treatment, both novel and established. In the present study we investigated the ratio of circulating nitric oxide to endothelin-1 in patients with both SSc and PAH, and determined whether polymorphisms in NOS2 (the nitric oxide synthase 2 gene) are associated with susceptibility to PAH. Endothelin-1 in plasma and nitric oxide metabolites (nitrate and nitrite) in serum were measured. The nitric oxide/endothelin-1 ratio was significantly lower in patients with both SSc and PAH than in patients with SSc only or in healthy control individuals. We confirmed the presence of two single nucleotide polymorphisms at positions -1,026 and -277 and a pentanucleotide repeat (CCTTT) at -2.5 kilobases. There were significant differences in single nucleotide polymorphisms between patients with SSc who had PAH and those who did not, and between patients with both SSc and PAH and healthy control individuals. The CCTTT repeat was significantly shorter in patients with both SSc and PAH than in patients with SSc only or in healthy control individuals. Transcriptional activity were analyzed using the luciferase reporter assay. The transcriptional activity of NOS2 was much greater in fibroblasts transfected by a vector with a long allele of the CCTTT repeat than in those transfected by a vector with a short allele. Polymorphisms in the NOS2 gene are associated with transcriptional activity of the NOS2 gene and with susceptibility to SSc-related PAH

Microfluidic Device for Simple Diagnosis of Plant Growth Condition by Detecting miRNAs from Filtered Plant Extracts

植物の生育状態を野外で早期診断できる装置を開発〜ストレスに応答して生じるmiRNAを葉から検出〜.京都大学プレスリリース. 2024-04-04.Plants are exposed to a variety of environmental stress, and starvation of inorganic phosphorus can be a major constraint in crop production. In plants, in response to phosphate deficiency in soil, miR399, a type of microRNA (miRNA), is up-regulated. By detecting miR399, the early diagnosis of phosphorus deficiency stress in plants can be accomplished. However, general miRNA detection methods require complicated experimental manipulations. Therefore, simple and rapid miRNA detection methods are required for early plant nutritional diagnosis. For the simple detection of miR399, microfluidic technology is suitable for point-of-care applications because of its ability to detect target molecules in small amounts in a short time and with simple manipulation. In this study, we developed a microfluidic device to detect miRNAs from filtered plant extracts for the easy diagnosis of plant growth conditions. To fabricate the microfluidic device, verification of the amine-terminated glass as the basis of the device and the DNA probe immobilization method on the glass was conducted. In this device, the target miRNAs were detected by fluorescence of sandwich hybridization in a microfluidic channel. For plant stress diagnostics using a microfluidic device, we developed a protocol for miRNA detection by validating the sample preparation buffer, filtering, and signal amplification. Using this system, endogenous sly-miR399 in tomatoes, which is expressed in response to phosphorus deficiency, was detected before the appearance of stress symptoms. This early diagnosis system of plant growth conditions has a potential to improve food production and sustainability through cultivation management

Predictive value of clinical and electrophysiological variables in patients with chronic chagasic cardiomyopathy and nonsustained ventricular tachycardia

OBJECTIVE: Risk stratification of patients with nonsustained ventricular tachycardia (NSVT) and chronic chagasic cardiomyopathy (CCC). METHODS: Seventy eight patients with CCC and NSVT were consecutively and prospectively studied. All patients underwent to 24-hour Holter monitoring, radioisotopic ventriculography, left ventricular angiography, and electrophysiologic study. With programmed ventricular stimulation. RESULTS: Sustained monomorphic ventricular tachycardia (SMVT) was induced in 25 patients (32%), NSVT in 20 (25.6%) and ventricular fibrillation in 4 (5.1%). In 29 patients (37.2%) no arrhythmia was inducible. During a 55.7-month-follow-up, 22 (28.2%) patients died, 16 due to sudden death, 2 due to nonsudden cardiac death and 4 due to noncardiac death. Logistic regression analysis showed that induction was the independent and main variable that predicted the occurrence of subsequent events and cardiac death (probability of 2.56 and 2.17, respectively). The Mantel-Haenszel chi-square test showed that survival probability was significantly lower in the inducible group than in the noninductible group. The percentage of patients free of events was significantly higher in the noninducible group. CONCLUSION: Induction of SMVT during programmed ventricular stimulation was a predictor of arrhythmia occurrence cardiac death and general mortality in patients with CCC and NSVT.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL

Production of Curium by the Neutron Irradiation of Americium-241

^Am was irradiated by the Japan Material Testing Reactor. The group separation of transuranium elements from fission products and cladding materials were carried out, and then Np, Pu, Am and Cm were isolated by using the ion exchange method. The isotopic ratios of Cm and Am were determined by the α- and γ-ray spectrometry

Irradiation of Natural Uranium by the Neutrons of the Japan Material Testing Reactor

A 2.76 g of natural uranium dioxide was irradiated by the neturons of JMTR for about 60 days from the 7th cycle to the 9th cycle. U and Pu were isolated and the isotopic ratios were measured. The nature of the neturon capture reactions was discussed

Observation of α-decay of ^<229m>Th produced from ^<229>Ac(II. Radiochemistry)

We produced ^Th in the nuclear reaction ^Th(γ, p2n)^ Ac, followed by disintegration to ^Th. The α-decay signals from ^Th were searched for and the alpha-particle events of the energy region between 4.93MeV and 5.05MeV were observed in the separated thorium fraction from an actinium source highly purified from the ^Th+γ reaction products. The energy values of the α-particles coincide with those expected for ^Th

ゲンパツセイ アルドステロンショウ ノ シンダン ニ ユウヨウナ リンショウ ショケン ノ ケントウ

Primary aldosteronism（PA）is known as a secondary hypertension. Hypertensive patients are screened by the plasma aldosterone concentration（PAC）／plasma renin activity（PRA）ratio as a case-detection test for PA. However, clinical parameters for screening patients with primary aldosteronism who need adrenalectomy have not been fully elucidated. We report a case of PA who received endoscopic adrenalectomy and evaluated the clinical parameters for screening patients with primary aldosteronism who need adrenalectomy, retrospectively. We evaluated４３patients with PAC/PRA＞２００as a screening test for PA. Thirty-three（７７％） patients were diagnoses as PA after confirmation test. In１８patients who received adrenal vein sampling, １０ patients were diagnoses as unilateral adrenal adenoma. We compared clinical parameters between PA and non-PA. The level of PAC was lower in patients with PA compared to that in patients with non-PA. There were no significant change in the level of PAC, PAC/PRA, serum potassium, and blood pressure. PAC and PAC/PRA were higher and serum potassium was lower in patients who received adrenalectomy compared to those in patients without adrenalectomy. ROC curve showed that PAC＞２００ pg/mL and serum potassium ＜３．５mEq/L were useful parameters to predict diagnosis of PA who need adrenalectomy. In conclusion, PA patients with PAC＞２００pg/mL and serum potassium ＜３．５mEq/L should be considered as candidates for adrenorectomy