Evidence of a sudden increase in the nuclear size of proton-rich silver-96.

Understanding the evolution of the nuclear charge radius is one of the long-standing challenges for nuclear theory. Recently, density functional theory calculations utilizing Fayans functionals have successfully reproduced the charge radii of a variety of exotic isotopes. However, difficulties in the isotope production have hindered testing these models in the immediate region of the nuclear chart below the heaviest self-conjugate doubly-magic nucleus 100Sn, where the near-equal number of protons (Z) and neutrons (N) lead to enhanced neutron-proton pairing. Here, we present an optical excursion into this region by crossing the N = 50 magic neutron number in the silver isotopic chain with the measurement of the charge radius of 96Ag (N = 49). The results provide a challenge for nuclear theory: calculations are unable to reproduce the pronounced discontinuity in the charge radii as one moves below N = 50. The technical advancements in this work open the N = Z region below 100Sn for further optical studies, which will lead to more comprehensive input for nuclear theory development.

Angular momentum generation in nuclear fission.

When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning1; this phenomenon has been a mystery in nuclear physics for over 40 years2,3. The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum4-12. Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the γ-ray heating problem in nuclear reactors13,14, for the study of the structure of neutron-rich isotopes15,16, and for the synthesis and stability of super-heavy elements17,18.

Pseudospin Symmetry and Microscopic Origin of Shape Coexistence in the

Lifetime measurements of excited states of the light N=52 isotones ^{88}Kr, ^{86}Se, and ^{84}Ge have been performed, using the recoil distance Doppler shift method and VAMOS and AGATA spectrometers for particle identification and gamma spectroscopy, respectively. The reduced electric quadrupole transition probabilities B(E2;2^{+}→0^{+}) and B(E2;4^{+}→2^{+}) were obtained for the first time for the hard-to-reach ^{84}Ge. While the B(E2;2^{+}→0^{+}) values of ^{88}Kr, ^{86}Se saturate the maximum quadrupole collectivity offered by the natural valence (3s, 2d, 1g_{7/2}, 1h_{11/2}) space of an inert ^{78}Ni core, the value obtained for ^{84}Ge largely exceeds it, suggesting that shape coexistence phenomena, previously reported at N≲49, extend beyond N=50. The onset of collectivity at Z=32 is understood as due to a pseudo-SU(3) organization of the proton single-particle sequence reflecting a clear manifestation of pseudospin symmetry. It is realized that the latter provides actually reliable guidance for understanding the observed proton and neutron single particle structure in the whole medium-mass region, from Ni to Sn, pointing towards the important role of the isovector-vector ρ field in shell-structure evolution.

_{36}

Prompt γ-ray spectroscopy of the neutron-rich ^{96}Kr, produced in transfer- and fusion-induced fission reactions, has been performed using the combination of the Advanced Gamma Tracking Array and the VAMOS++ spectrometer. A second excited state, assigned to J^{π}=4^{+}, is observed for the first time, and a previously reported level energy of the first 2^{+} excited state is confirmed. The measured energy ratio R_{4/2}=E(4^{+})/E(2^{+})=2.12(1) indicates that this nucleus does not show a well-developed collectivity contrary to that seen in heavier N=60 isotones. This new measurement highlights an abrupt transition of the degree of collectivity as a function of the proton number at Z=36, of similar amplitude to that observed at N=60 at higher Z values. A possible reason for this abrupt transition could be related to the insufficient proton excitations in the g_{9/2}, d_{5/2}, and s_{1/2} orbitals to generate strong quadrupole correlations or to the coexistence of competing different shapes. An unexpected continuous decrease of R_{4/2} as a function of the neutron number up to N=60 is also evidenced. This measurement establishes the Kr isotopic chain as the low-Z boundary of the island of deformation for N=60 isotones. A comparison with available theoretical predictions using different beyond mean-field approaches shows that these models fail to reproduce the abrupt transitions at N=60 and Z=36.

First Evidence of Shape Coexistence in the

The N=48 ^{80}Ge nucleus is studied by means of ß-delayed electron-conversion spectroscopy at ALTO. The radioactive ^{80}Ga beam is produced through the isotope separation on line photofission technique and collected on a movable tape for the measurement of γ and e^{-} emission following ß decay. An electric monopole E0 transition, which points to a 639(1) keV intruder 0_{2}^{+} state, is observed for the first time. This new state is lower than the 2_{1}^{+} level in ^{80}Ge, and provides evidence of shape coexistence close to one of the most neutron-rich doubly magic nuclei discovered so far, ^{78}Ni. This result is compared with theoretical estimates, helping to explain the role of monopole and quadrupole forces in the weakening of the N=50 gap at Z=32. The evolution of intruder 0_{2}^{+} states towards ^{78}Ni is discussed.

[Cancer-related bone pain in children]. / Douleurs et tumeurs osseuses malignes de l'enfant et de l'adolescent.

Pain often discloses the existence of bone tumors in children. The complex physiopathology of pain in malignant bone tumors remains largely unknown and is currently investigated. Cancer-related bone pain is independent from the type and the location of the tumor, and from the number and size of the malignant lesions. It does not necessarily increase with tumor growth. Pain, which is the most common early symptom of bone cancer, may also be present at every step of the disease. It may arise from postsurgery injury, side effects of chemo- or radiotherapy, tumor evolution, secondary sequels of treatments, phantom pain. Tumor eradication using cancer therapeutic strategies is the major etiological treatment option for bone cancer pain. Symptom control requires multidisciplinary medical management with drugs effective against bone lysis, analgesics, drugs with anti-neuropathic activity, as well as non-pharmacological techniques and psycho-social management. This psycho-social management must be tailored to the specific needs of teenagers who are particularly prone to this pathological manifestation. Measures to prevent the occurrence of residual chronic pain must be implemented, whereas children and their family should be clearly informed of the risks and of analgesic options available.

Effects of muscle group recruitment on sniff transdiaphragmatic pressure and its components.

Measuring maximal sniff pressures is an easy way of assessing inspiratory muscle strength. During a static manoeuvre, the pattern of inspiratory muscle recruitment during a sniff can vary from one individual to another. We therefore assessed how voluntarily changing muscle recruitment would affect sniff oesophageal, gastric and transdiaphragmatic pressures (Pes,sn, Pga,sn and Pdi,sn, respectively). Ten normal subjects (age 27-38 years) performed natural sniff manoeuvres ("nat"), and preferentially diaphragmatic ("dia") or extradiaphragmatic ("extradia") sniff manoeuvres, after having learnt to dissociate between the inspiratory muscle groups. Abdominal displacements were monitored using a belt-mounted strain gauge. Natural patterns of muscle recruitment varied among subjects. On average, Pes,sn,nat was [median (range)] 81 (21-105) cmH2O. All of the subjects were able to modify inspiratory muscle recruitment voluntarily. Pes,sn was not significantly affected by the type of manoeuvre performed, as opposed to Pdi,sn, which, as expected, increased with both the diaphragmatic and extradiaphragmatic manoeuvres [Pdi,sn,dia 132 (99-157) cmH2O, Pdi,sn,extradia 96 (50-146) cmH2O, P<0.05]. Whatever the manoeuvre, there was no correlation between Pes and Pdi, but Pga and Pdi were correlated during both the diaphragmatic (r = 0.82, P < 0.05) and the extradiaphragmatic manoeuvre (r = 0.70, P < 0.05). Pes,sn may have limitations as an index of diaphragm function, but by showing its independence from inspiratory muscle recruitment, this study contributes to its validation as a robust index of global inspiratory muscle strength that is particularly well suited for follow-up studies. This should extend to Pes,sn substitutes measured at the airway opening.

Evaluation of caudal anaesthesia performed in conscious ex-premature infants for inguinal herniotomies.

Ex-premature infants, before 45 weeks postconceptional age, are at high-risk of apnoea after surgery. General anaesthesia increases the risk of apnoea. We evaluated the tolerance and the efficiency of caudal anaesthesia performed in 25 consecutive conscious ex-premature infants for inguinal herniotomies. N2O/O2 and EMLA cream are used to facilitate caudal puncture. Anaesthesia procedure, patient comfort and complications following the 24 postoperative hours were studied. We report good anaesthesia conditions without compromising the baby's comfort and few perioperative complications. Only two infants with a prior history of apnoea or bronchopulmonary dysplasia had apnoea during and after surgery. A total spinal anaesthesia was the major complication in one infant and prolonged surgery requiring general anaesthesia was the main limitation of this technique in another child. The principal advantage of the procedure is to facilitate and simplify the postoperative management of the babies. The anaesthetic technique does not alter surgical conditions. Caudal epidural anaesthesia performed in awake high-risk preterm infants is beneficial for these infants but requires experienced operators.

Multiple organ failure complicating probable scrub typhus.

This report describes a case of life-threatening acute respiratory distress syndrome with multiple organ failure complicating probable scrub typhus. Favorable outcome was associated with fluoroquinolone therapy. Scrub typhus should be suspected in travelers returning from Southeast Asia presenting with unexplained respiratory manifestations.

Inducible expression and regulation of the alpha 1-acid glycoprotein gene by alveolar macrophages: prostaglandin E2 and cyclic AMP act as new positive stimuli.

We have reported that alpha 1-acid glycoprotein (AGP) gene expression was induced in lung tissue and in alveolar type II cells during pulmonary inflammatory processes, suggesting that local production of this immunomodulatory protein might contribute to the modulation of inflammation within the alveolar space. Because AGP may also be secreted by other cell types in the alveolus, we have investigated the expression and the regulation of the AGP gene in human and rat alveolar macrophages. Spontaneous AGP secretion by alveolar macrophages was increased 4-fold in patients with interstitial lung involvement compared with that in controls. In the rat, immunoprecipitation of [35S]methionine-labeled cell lysates showed that alveolar macrophages synthesize and secrete AGP. IL-1 beta had no effect by itself, but potentiated the dexamethasone-induced increase in AGP production. RNase protection assay demonstrated that AGP mRNA, undetectable in unstimulated cells, was induced by dexamethasone. Conditioned medium from LPS-stimulated macrophages as well as IL-1 beta had no effect by themselves, but potentiated the dexamethasone-induced increase in AGP mRNA levels. In addition to cytokines, PGE2 as well as dibutyryl cAMP increased AGP mRNA levels in the presence of dexamethasone. When AGP expression in other cells of the monocyte/macrophage lineage was examined, weak and no AGP production by human blood monocytes and by rat peritoneal macrophages, respectively, were observed. Our data showed that 1) AGP expression is inducible specifically in alveolar macrophages in vivo and in vitro; and 2) PGE2 and cAMP act as new positive stimuli for AGP gene expression.

[Pain in hospitalized children]. / La douleur de l'enfant hospitalisé.

Pain is present in many hospitalized children and this requires from every physician a constant attention to its recognition, evaluation and treatment. The semeiology of pain differs whether it is acute or chronic. Acute pain can be recognized from its various behavioural, motor and neurovegetative manifestations. Pain evaluation must be adapted according to age: autoevaluation procedures for children older than 5 years, behavioural scales for children younger than 5 years. One must know that there is an appropriate and efficient treatment for each stage of pain intensity. For a better recognition and management of pain in hospitalized children, the organization of teams specialized in the evaluation and treatment of pain in children is to be encouraged.

[Perforation of a jejunal diverticulum]. / Perforation d'un diverticule jéjunal.

An observation of jejunal diverticulum is reported by the authors. It concerned a woman 82 years old whose disease appeared as an acute white spread peritonitis complication. The delay brought to perform the operation made it impossible to save diseased. About that case is evoked the pathogeny of the diverticulum: congenital or acquired. In the case reported it was acquired, the proof resulting from the anatomy-pathology. The disease can appear under a chronicle form with a difficult diagnosis or under a single relevant form whose surgical treatment must be done without delay.

Squamous-cell carcinoma antigen (SCC-A) values related to clinical outcome of pre-invasive and invasive cervical carcinoma.

The serum concentration of squamous-cell carcinoma antigen (SCC-A), a subfraction of tumour antigen, was determined by RIA from healthy donors (control group) and from patients with malignant cervical disease. Ninety-six percent (173/180) of the healthy patients had squamous-cell carcinoma antigen serum levels below 2 ng/ml. Ten of 70 (14.3%) patients with CIN III, 53.8% (34/62) of patients with invasive squamous-cell carcinoma stage I, 85.8% (30/35) with stage II and 96.5% (27/28) with stage III/IV had squamous-cell carcinoma antigen serum levels above 2 ng/ml. We observed that 22.5% (11/49) of patients with a tumour volume below 10 ml and 92.6% of patients with a tumour volume greater than 10 ml had squamous-cell carcinoma antigen levels above 2 ng/ml (p less than 0.005). SCC-A was correlated with recurrence or progressive disease in 90.0% of cases. Other risk factors such as depth of invasion, microscopic parametrial involvement, lymphatic and/or vascular space permeation and histological grade were not correlated with squamous-cell carcinoma antigen. Furthermore, this marker increased 4.3 +/- 2.7 months before clinical evidence of recurrence or progressive disease. We conclude that serial serum levels of squamous-cell carcinoma antigen provide a means for early detection of recurrence or progressive disease. This tumour marker might also be useful for monitoring the treatment effects and has some prognostic value.

Necrotizing tracheobronchitis: a complication of high frequency jet ventilation.

The tracheal and bronchial lesions observed are described in seven patients, presenting with respiratory distress syndrome and receiving both conventional and high frequency jet ventilation for various periods. The histological findings are related to the duration of the exposure as well as the number of pulsations administered to the tracheobronchial tree. Severe damage to the mucosa leading to acute tracheobronchitis, hyperplasia and hypersecretion of the mucosal glands may explain some of the clinical symptoms observed, especially the upper respiratory obstruction. Care should be taken to limit these changes which may lead to various degrees of stenosis in survivors receiving this mode of therapy.