Nanosecond-Scale Proton Emission from Strongly Oblate-Deformed

Using the fusion-evaporation reaction ^{96}Ru(^{58}Ni,p4n)^{149}Lu and the MARA vacuum-mode recoil separator, a new proton-emitting isotope ^{149}Lu has been identified. The measured decay Q value of 1920(20) keV is the highest measured for a ground-state proton decay, and it naturally leads to the shortest directly measured half-life of 450_{-100}^{+170} ns for a ground-state proton emitter. The decay rate is consistent with l_{p}=5 emission, suggesting a dominant πh_{11/2} component for the wave function of the proton-emitting state. Through nonadiabatic quasiparticle calculations it was concluded that ^{149}Lu is the most oblate deformed proton emitter observed to date.

Lifetime Measurements of Excited States in

Lifetimes of the first excited 2^{+} and 4^{+} states in the extremely neutron-deficient nuclide ^{172}Pt have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+})=0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segré chart. The observation adds to a cluster of a few extremely neutron-deficient nuclides of the heavy transition metals with neutron numbers N≈90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2:4_{1}^{+}→2_{1}^{+})/B(E2:2_{1}^{+}→0_{gs}^{+}) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N≈90-94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.

Decay and Fission Hindrance of Two- and Four-Quasiparticle K Isomers in

Two isomers decaying by electromagnetic transitions with half-lives of 4.7(1.1) and 247(73) µs have been discovered in the heavy ^{254}Rf nucleus. The observation of the shorter-lived isomer was made possible by a novel application of a digital data acquisition system. The isomers were interpreted as the K^{π}=8^{-}, ν^{2}(7/2^{+}[624],9/2^{-}[734]) two-quasineutron and the K^{π}=16^{+}, 8^{-}ν^{2}(7/2^{+}[624],9/2^{-}[734])⊗8^{-}π^{2}(7/2^{-}[514],9/2^{+}[624]) four-quasiparticle configurations, respectively. Surprisingly, the lifetime of the two-quasiparticle isomer is more than 4 orders of magnitude shorter than what has been observed for analogous isomers in the lighter N=150 isotones. The four-quasiparticle isomer is longer lived than the ^{254}Rf ground state that decays exclusively by spontaneous fission with a half-life of 23.2(1.1) µs. The absence of sizable fission branches from either of the isomers implies unprecedented fission hindrance relative to the ground state.

Shell-structure and pairing interaction in superheavy nuclei: rotational properties of the z=104 nucleus (256)rf.

The rotational band structure of the Z=104 nucleus (256)Rf has been observed up to a tentative spin of 20ℏ using state-of-the-art γ-ray spectroscopic techniques. This represents the first such measurement in a superheavy nucleus whose stability is entirely derived from the shell-correction energy. The observed rotational properties are compared to those of neighboring nuclei and it is shown that the kinematic and dynamic moments of inertia are sensitive to the underlying single-particle shell structure and the specific location of high-j orbitals. The moments of inertia therefore provide a sensitive test of shell structure and pairing in superheavy nuclei which is essential to ensure the validity of contemporary nuclear models in this mass region. The data obtained show that there is no deformed shell gap at Z=104, which is predicted in a number of current self-consistent mean-field models.

Effects of irradiation on mandibular scintigraphy.

Technetium-99m methylene diphosphonate (Sn) scintigraphy with computer analysis was used to investigate alterations in the pathophysiology of the normal mandible and the pathologic mandible during and after irradiation. Slight but significant elevations of uptake levels were recorded as an early effect of irradiation. The elevations correlated with the duration of treatment and normalized over a follow-up period of 6 to 12 mo. Increased mandibular metabolism was found during irradiation and in osteomyelitis and osteoradionecrosis of the mandible. Scintigraphy with computer analysis proved a simple and valid method in the evaluation of early irradiation damage and pathophysiologic conditions of the mandible. The method can also be used to predict whether the irradiation damage will become irreversible.

Ovarian function during and after curative intracavitary high dose-rate irradiation: steroidal output and morphology.

The endocrinological function of the ovary during and after curative intracavitary high dose-rate irradiation has been studied by determining the peripheral plasma levels of P, E1, E2, FSH, LH and PROL in 8 patients aged 37 +/- 7 yr (+/- SD). In addition, the concentrations of E1 and E2 in ovarian venous blood during the estimated ovulatory phase after irradiation were determined. The functional structure of the ovary was studied histochemically using 3 beta-hydroxysteroid dehydrogenase (HSD) and ultrastructurally and histologically with routine methods. The results during and after irradiation were compared to those before irradiation. In addition, 28 postmenopausal patients were used as controls. At the end of the irradiation course, which lasted from the premenstrual to the ovulatory phase, 3 out of 4 patients with cervical carcinoma had normal plasma P levels; the menstrual cycles of these patients was previously ovulatory. The normal P levels as well as a rise in E1 and E2 concentrations indicate ovulation. During the next menstrual cycle these values and the E2/E1 ratio in peripheral venous blood decreased and the levels of FSH and LH rose to the postmenopausal values. In patients with endometrial carcinoma, the menstrual cycle was anovulatory both before and after radiotherapy; in estrogen and gonadotrophin levels, similar changes were observed as in patients having ovulatory cycles. In ovarian venous blood, the E2 plasma levels and the E2/E1 ratios were in both groups significantly higher at the time of the second potential ovulatory phase than the corresponding postmenopausal values. As in the postmenopausal women, both E1 and E2 levels in irradiated patients were higher in ovarian effluent blood than peripherally. The ovarian/cubital E1 ratios did not differ between these groups. For E2, this ratio was, however, significantly higher in irradiated patients than in postmenopausal controls. The morphological findings--both by light and electron microscopy--as well as the enzyme-histochemical studies support the chemical results reflecting a decreased yet significant estrogen production in the ovaries after irradiation.

A new method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. Clinical and hormonal studies.

The authors present a new method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. The problem with this method has been how to inactivate the endometrium while maintaining the physiological function of the ovaries. In 5/29 young patients regular or irregular bleedings occurred after an endometrial dose of 11 +/- 1 Gy. These subjects were given a repeat low dose intrauterine irradiation. Thereafter no bleedings were found in four out of five patients. Two to 9 years after the repeat irradiation the plasma levels of E1, E2, FSH and LH corresponded closely to those of healthy women in reproductive age in three out of five patients; some high plasma P levels indicated ovulation. In two patients the E1, E2 and P values were more likely postmenopausal but, on the other hand, FSH and LH values reproductive ones. The endocrinological studies after one irradiation [5] and the medico-legal [15] and neuropsychiatric [17] aspects relevant to the method are presented elsewhere.

Scintigraphy in early detection of mandibular disorders.

Technetium methylenediphosphonate scintigraphy was used to study the effect of irradiation on mandibular uptake. Determination of relative mandibular uptake allows comparison of results in different subjects, while determination of individual normalized mandibular uptake increases the significance of differences found in the same subject at different times. A very uniform increase of about 25% was recorded after radiotherapy of about 50 Gy; the uptake returned to pretherapeutic levels in 9 months. Osteoradionecrosis--and especially osteomyelitis--clearly increases the uptakes above the values of the irradiation effect. To increase the usefulness of scintigraphy in the early detection of an imminent complication, we recommend pretherapeutic control scintigraphy in all cases liable to such complications.

A community-based intervention study on the feasibility and effects of the reduction of salt intake in North Karelia, Finland.

A community-based programme to reduce salt consumption to lower general blood pressure levels has been started in North Karelia, a county eastern Finland with high hypertension and CVD rates. The programme is based on the previous activity in the community to control CVD risk factors (the North Karelia Project). Previously, however, salt reduction was not included among the objectives. The aim of the study is to evaluate the feasibility and effects of this new community programme to reduce salt intake. The study period is from spring 1979 to spring 1982. At the outset and at the end cross-sectional random population samples, ages 14 to 65, are examined both in North Karelia and a matched reference community. The surveys include among other measurements 24-hour urine collection (for Na, K and creatinine excretion) and blood pressure. The effect evaluation is concerned whether the programme reduced the general salt intake and whether this was associated with reduction in blood pressure levels among the population. Principles and methods of intervention are presented. Preliminary results from the baseline survey confirmed the high salt intake of the population: the mean 24-hour urinary Na excretion was 215-218 mmol among men and 171-173 mmol among women. The respective K excretion values were 89-91 mmol and 72-72 mmol, and Na/K ratios 2.5-2.6 and 2.4-2.5.

Sharing electronic medical record on the WWW using InterCare architecture and smart cards.

Southern-Finland is a partner of the European Commission funded telematics project, InterCare, which is developing and demonstrating the WWW--based regional architecture and application integrated with smart cards. The InterCare project will combine the results from the most important EC funded healthcare telematics projects in their respective areas--Cardlink 2, Hector, Star, Synapses and TrustHealth. The primary objective is to achieve a convergence of results and to demonstrate & promote the synergy between projects from different areas of the healthcare telematics programme.

Comparison of gamma-ray coincidence and low-background gamma-ray singles spectrometry.

Aerosol samples have been studied under different background conditions using gamma-ray coincidence and low-background gamma-ray singles spectrometric techniques with High-Purity Germanium detectors. Conventional low-background gamma-ray singles counting is a competitive technique when compared to the gamma-gamma coincidence approach in elevated background conditions. However, measurement of gamma-gamma coincidences can clearly make the identification of different nuclides more reliable and efficient than using singles spectrometry alone. The optimum solution would be a low-background counting station capable of both singles and gamma-gamma coincidence spectrometry.

Gamma-ray spectroscopy at the limits: first observation of rotational bands in 255Lr.

The rotational band structure of 255Lr has been investigated using advanced in-beam gamma-ray spectroscopic techniques. To date, 255Lr is the heaviest nucleus to be studied in this manner. One rotational band has been unambiguously observed and strong evidence for a second rotational structure was found. The structures are tentatively assigned to be based on the 1/2-[521] and 7/2-[514] Nilsson states, consistent with assignments from recently obtained alpha decay data. The experimental rotational band dynamic moment of inertia is used to test self-consistent mean-field calculations using the Skyrme SLy4 interaction and a density-dependent pairing force.

Effect of low dose endometrial after-loading irradiation upon the hypophysis-ovarian axis.

Endometrial inactivation by irradiation, while simultaneously preserving the ovarian function is sometimes clinically indicated. We have found that after 1100 cGy (rad) the ovarian function remains intact, yet endometrial inactivation is unsatisfactory. Therefore, four premenopausal subjects, with clinical indications for eliminating disturbing uterine bleedings, received each an endometrial dose of 1600 cGy by using a Cathetron afterloading unit. When pre- and post-treatment cycles were compared, the circulating gonadotrophin and estrogen levels were unchanged in three subjects. Nine to 12 weeks after the treatments there were no signs of ovulation and the gonadotrophin levels were generally increased. None of the subjects had experienced any bleedings. We conclude that an endometrial dose of 1600 cGy is effective in inactivating endometrium, but may also lead to an impaired ovarian function and to a premature menopause.

Accuracy of ultrasonic fetal weight estimation and detection of small for gestational age fetuses.

One hundred and eight-six pregnant women were studied with ultrasound for clinical suspicion of poor fetal growth. Fetal weight was estimated using biparietal diameter and mean abdominal diameter with a special nomogram. The fetal femur length (FL) to abdominal circumference (AC) ratio was also calculated. The mean interval between the last ultrasound examination and delivery was 9 days (range, 0 to 14 days). Eighty-three women had their last ultrasonic examination 0 to 4 days (mean, 2 days) before delivery. In this group the arithmetic mean of weight estimation errors was -1 gm (SD, 159 gm). The signed mean percent error was +0.6% (SD, 6.6%). Neither systematic nor random errors were found between different growth percentile groups. When small for gestational age (SGA) was defined as birthweight below 2.5 percentile, the sensitivity, specificity, and positive predictive value of the weight estimations were 82%, 92%, and 84%, respectively, in 186 cases. Significant differences were found in FL to AC ratios between growth pattern groups but fetal weight estimation was found to be superior in the detection of SGA fetuses.

Correlates of diuretic renography in experimental hydronephrosis.

We studied the correlations between diuretic renographs and kidney function in experimental hydronephrosis in rabbits. Features of furosemide-stimulated 99mTc-diethylenetriamine-pentaacetic acid renographs were compared to the growth rate, thirst test and endogenous creatinine clearance rate in a chronic solitary-kidney animal model. Intravenous pyelograms, done four weeks after laparotomy, left nephrectomy, bladder resection and constriction of the right pyeloureteric junction, showed signs of obstruction in all the 12 animals of the experimental group. An absent tracer washout after intravenous furosemide, found in five animals, was associated with retarded growth, isosthenuria and an abnormal creatinine clearance. In all of the other seven animals, a distinct tracer washout after intravenous furosemide was accompanied with a normal growth rate and creatinine clearance. However, no one of these seven animals had a normal ability to retain water and concentrate urine in the thirst test. We conclude that, in this experimental model, a furosemide-induced tracer washout from the kidney pelvis cannot be taken as a proof of the absence of any upper urinary tract obstruction.

Bone reaction in temporomandibular joint dysfunction. An investigation with bone scintigraphy and gamma imaging.

Scintigraphy was used in eight patients with temporomandibular joint dysfunction to detect changes in bone metabolism assumed to be responses to altered activity of the masticatory muscles. Asymmetry in clinical signs and symptoms coincided with the asymmetry observed in the computed horizontal tomograms.

Sodium intake reduction in volunteer families by using a salt substitute and nutrition counselling.

A double-blind study on the home use of regular salt (RS) and a salt substitute, called Mineral Salt (MS), was done in 58 volunteer families all with a 13-year-old child. All the salt used at home was replaced by one of the test salts for 4 months. After the first 2 months the parents were given a 5-hour course on reducing sodium intake by changing food habits. The test salt consumption was measured by weighing the leftover salt after 2 and 4 months. The parents and 13-year-old children collected 24-hour urine samples at the beginning of the study and after 2 and 4 months. The home use of test salt fell from 2.9 to 2.6 g/family member in the RS group (nonsignificant) and from 3.4 to 2.9 g in the MS group (significant at p less than 0.01). There were no statistically significant changes in the sodium or potassium urinary outputs during the study. The results indicate that the home use of MS alone or counselling on changing food habits alone or a combination of the two was not effective enough to reduce sodium intake to a degree detectable by the study methods.