Description of the Proton-Decaying 0_{2}^{+} Resonance of the α Particle

The recent precise experimental determination of the monopole transition form factor from the ground state of ^{4}He to its 0_{2}^{+} resonance via electron scattering has reinvigorated discussions about the nature of this first excited state of the α particle. The 0_{2}^{+} state has been traditionally interpreted in the literature as the isoscalar monopole resonance (breathing mode) or, alternatively, as a particle-hole shell-model excitation. To better understand the nature of this state, which lies only ∼410  keV above the proton emission threshold, we employ the coupled-channel representation of the no-core Gamow shell model. By considering the [^{3}H+p], [^{3}He+n], and [^{2}H+^{2}H] reaction channels, we explain the excitation energy and monopole form factor of the 0_{2}^{+} state. We argue that the continuum coupling strongly impacts the nature of this state, which carries characteristics of the proton decay threshold.

Strong Evidence for ^{9}N and the Limits of Existence of Atomic Nuclei

The boundaries of the chart of nuclides contain exotic isotopes that possess extreme proton-to-neutron asymmetries. Here we report on strong evidence of ^{9}N, one of the most exotic proton-rich isotopes where more than one half of its constitute nucleons are unbound. With seven protons and two neutrons, this extremely proton-rich system would represent the first-known example of a ground-state five-proton emitter. The invariant-mass spectrum of its decay products can be fit with two peaks whose energies are consistent with the theoretical predictions of an open-quantum-system approach; however, we cannot rule out the possibility that only a single resonancelike peak is present in the spectrum.

Multimodal imaging assessment of left atrial strain in cardiac amyloidosis and hypertrophic cardiomyopathies

Funding Acknowledgements

Type of funding sources: None.

Background

Despite the increasing number of studies concerning Left Atrial Strain (LAS), few data are available comparing LAS patients with cardiac amyloidosis (CA) and sarcomeric hypertrophic cardiomyopathies (HCM).

Purposes

We aimed to perform a comparative multimodal imaging analysis of LAS of a prospective cohort of patients with CA and HCM.

Methods

For each enrolled patient, we performed same-day two and three-dimension echocardiography (TTE) and cardiac magnetic resonance imaging (CMR) to blindly measure the peak atrial longitudinal strain (PALS) and the peak atrial contraction strain (PACS). Patients with acute atrial fibrillation were excluded.

Results

  Between January 2020 and July 2021, 67 patients were included: 31 patients with CA (age 75.1 ± 10 years, left ventricular ejection fraction 60.6 ± 10.4%, maximum left ventricular thickness 17.8 ± 3.9 mm) and 36 with HCM (age 50.8 ± 15.5 years, left ventricular ejection fraction 66.1 ± 9.8%, maximum left ventricular thickness 20.7 ± 4.5 mm). Left atrial volume was similar in the 2 groups (42.5 ± 15.6 mL/m2 in HCM vs 47.9 ± 15 in CA, P = 0.1557).

Concerning PALS, its values for CA and for CMH were on 2D TTE manual (10.9 ± 5.8% vs 21.4 ± 9.4%, P < 0.001), 2D TTE automatic (11.5 ± 7.3% vs 22.9 ± 10.2%, P < 0.001), 3D TTE (10 ± 6.8% vs 18.1 ± 6.7%, P < 0.001), and CMR (11.3 ± 8 vs 24.4 ± 17.1, P < 0.001) respectively.

Concerning PACS, its values for CA and for CMH were on 2D TTE manual (5.2 ± 3.4% vs 10 ± 4%, P < 0.001), 2D TTE automatic (4.9 ± 3.9% vs 10.2 ± 5.1%, P < 0.001), 3D TTE (3.6 ± 3.8% vs 7.9 ± 4%, P = 0.001) and CMR (6.2 ± 5.8% vs 11.9 ± 9%, P = 0.004) respectively.

Multivariate analysis adjusted on main factors influencing LAS (left ventricular (LV) mass, LV ejection fraction, LV global longitudinal strain, renal function and history of hypertension) found that the differences between the two groups remained significant for PALS and PACS for almost all technics.

Furthermore, although concordance between the 3 echocardiographic technics was excellent (the interclass correlation coefficient (ICC) was higher than 0.80 between each TTE methods), ICC was poor between TTE and CMR technics: 0.40 (0.18-0.59) for manual 2D TTE and CMR, 0.46 (0.24-0.63) for auto 2D TTE and CMR, 0.40 (0.14-0.60) for 3D TTE and CMR.

Conclusion

Our study is the first to describe and compare, both on TTE and CMR, LAS on a prospective cohort of patients with CA and HCM. Although they have same mean left atrial volume, we found significant differences on PALS and PACS between these two groups of patients on all the studied technics. These findings may be used in future multi-modality imaging studies dealing with diagnosis or prognosis of these hypertrophic cardiopathies. Abstract Figure. LAS 2D TTE manual  Abstract Figure. LAS comparison between CA and HCM

First Observation of the Four-Proton Unbound Nucleus ^{18}Mg

^{18}Mg was observed, for the first time, by the invariant-mass reconstruction of ^{14}O+4p events. The ground-state decay energy and width are E_{T}=4.865(34)  MeV and Γ=115(100)  keV, respectively. The observed momentum correlations between the five particles are consistent with two sequential steps of prompt 2p decay passing through the ground state of ^{16}Ne. The invariant-mass spectrum also provides evidence for an excited state at an excitation energy of 1.84(14) MeV, which is likely the first excited 2^{+} state. As this energy exceeds that for the 2^{+} state in ^{20}Mg, this observation provides an argument for the demise of the N=8 shell closure in nuclei far from stability. However, in open systems this classical argument for shell strength is compromised by Thomas-Ehrman shifts.

Quasifree Neutron Knockout Reaction Reveals a Small s-Orbital Component in the Borromean Nucleus ^{17}B

A kinematically complete quasifree (p,pn) experiment in inverse kinematics was performed to study the structure of the Borromean nucleus ^{17}B, which had long been considered to have a neutron halo. By analyzing the momentum distributions and exclusive cross sections, we obtained the spectroscopic factors for 1s_{1/2} and 0d_{5/2} orbitals, and a surprisingly small percentage of 9(2)% was determined for 1s_{1/2}. Our finding of such a small 1s_{1/2} component and the halo features reported in prior experiments can be explained by the deformed relativistic Hartree-Bogoliubov theory in continuum, revealing a definite but not dominant neutron halo in ^{17}B. The present work gives the smallest s- or p-orbital component among known nuclei exhibiting halo features and implies that the dominant occupation of s or p orbitals is not a prerequisite for the occurrence of a neutron halo.

First Observation of ^{20}B and ^{21}B

The most neutron-rich boron isotopes ^{20}B and ^{21}B have been observed for the first time following proton removal from ^{22}N and ^{22}C at energies around 230  MeV/nucleon. Both nuclei were found to exist as resonances which were detected through their decay into ^{19}B and one or two neutrons. Two-proton removal from ^{22}N populated a prominent resonancelike structure in ^{20}B at around 2.5 MeV above the one-neutron decay threshold, which is interpreted as arising from the closely spaced 1^{-},2^{-} ground-state doublet predicted by the shell model. In the case of proton removal from ^{22}C, the ^{19}B plus one- and two-neutron channels were consistent with the population of a resonance in ^{21}B 2.47±0.19  MeV above the two-neutron decay threshold, which is found to exhibit direct two-neutron decay. The ground-state mass excesses determined for ^{20,21}B are found to be in agreement with mass surface extrapolations derived within the latest atomic-mass evaluations.

Can Tetraneutron be a Narrow Resonance?

The search for a resonant four-neutron system has been revived thanks to the recent experimental hints reported in [1]. The existence of such a system would deeply impact our understanding of nuclear matter and requires a critical investigation. In this work, we study the existence of a four-neutron resonance in the quasistationary formalism using ab initio techniques with various two-body chiral interactions. We employ no-core Gamow shell model and density matrix renormalization group method, both supplemented by the use of natural orbitals and a new identification technique for broad resonances. We demonstrate that while the energy of the four-neutron system may be compatible with the experimental value, its width must be larger than the reported upper limit, supporting the interpretation of the experimental observation as a reaction process too short to form a nucleus.

Fipronil and two of its transformation products in water and European eel from the river Elbe

Fipronil is an insecticide which, based on its mode of action, is intended to be predominantly toxic towards insects. Fipronil bioaccumulates and some of its transformation products were reported to be similar or even more stable in the environment and to show an enhanced toxicity against non-target organisms compared to the parent compound. The current study investigated the occurrence of Fipronil and two of its transformation products, Fipronil-desulfinyl and Fipronil-sulfone, in water as well as muscle and liver samples of eels from the river Elbe (Germany). In water samples total concentrations of FIP, FIP-d and FIP-s ranged between 0.5-1.6ngL(-1) with FIP being the main component in all water samples followed by FIP-s and FIP-d. In contrast, FIP-s was the main component in muscle and liver tissues of eels with concentrations of 4.05±3.73ngg(-1) ww and 19.91±9.96ngg(-1) ww, respectively. Using a physiologically based toxicokinetic (PBTK) model for moderately hydrophobic organic chemicals, the different distributions of FIP, FIP-d and FIP-s in water and related tissue samples could be attributed to metabolic processes of eels. The measured concentrations in water of all analytes and their fractional distribution did not reflect the assumed seasonal application of FIP and it seems that the water was constantly contaminated with FIP, FIP-d and FIP-s.

Deuteron induced Tb-155 production, a theranostic isotope for SPECT imaging and auger therapy

Several terbium isotopes are suited for diagnosis or therapy in nuclear medicine. Tb-155 is of interest for SPECT imaging and/or Auger therapy. High radionuclide purity is mandatory for many applications in medicine. The quantification of the activity of the produced contaminants is therefore as important as that of the radionuclide of interest. The experiments performed at the ARRONAX cyclotron (Nantes, France), using the deuteron beam delivered up to 34MeV, provide an additional measurement of the excitation function of the Gd-nat(d,x)Tb-155 reaction and of the produced terbium and gadolinium contaminants. In this study, we investigate the achievable yield for each radionuclide produced in natural gadolinium as a function of the deuteron energy. Other reactions are discussed in order to define the production route that could provide Tb-155 with a high yield and a high radionuclide purity. This article aims to improve data for the Gd-nat(d,x) reaction and to optimize the irradiation conditions required to produce Tb-155.

New beam monitoring tool for radiobiology experiments at the cyclotron ARRONAX

The ARRONAX cyclotron is able to deliver alpha particles at 68 MeV. In the frame of radiological research, a new method is studied to infer in situ the deposited dose: it is based on the online measurement of the bremsstrahlung (>1 keV) produced by the interaction of the incident particle with the medium. Experiments are made using bombarded poly(methyl methacrylate) (PMMA)-equivalent water targets in order to characterise this continuous X-ray spectrum. The intensity of the bremsstrahlung spectrum allows for the beam monitoring. A simulation code of the bremsstrahlung has been built, and a good agreement is found with the experimental spectra. With this simulation, it is possible to predict the sensibility of this method: it varies with the target thickness, showing a good sensibility for thin target (<1000 µm) and saturation for thicker ones. Bremsstrahlung spectrum also shows a sensibility on the target's chemical composition.

Cross section measurements of deuteron induced nuclear reactions on natural titanium up to 34 MeV

Experimental cross sections for deuteron induced nuclear reactions on natural titanium were measured, using the stacked-foil technique and gamma spectrometry, up to 34 MeV with beams provided by the ARRONAX cyclotron. The experimental cross section values were monitored using the (nat)Ti(d,x)(48)V reaction, recommended by the IAEA. The excitation functions for (nat)Ti(d,x)(44m,46,47,48)Sc are presented and compared with the existing ones and with the TALYS 1.6 code calculations using default models. Our experimental values are in good agreement with data found in the literature. TALYS 1.6 is not able to give a good estimation of the production cross sections investigated in this work. These production cross sections of scandium isotopes fit with the new Coordinated Research Project (CRP) launched by the International Atomic Energy Agency (IAEA) to expand the database of monitor reactions.

EBT2 films response to alpha radiation at 48.3 MeV

To advance the development of a radiobiological experimental set-up for alpha particle irradiations at the Arronax cyclotron, experiments were performed to get the dose response of Gafchomic EBT2 films for alpha particles at 48.3 MeV. A system has been developed using a thin monitor copper foil and an X-ray spectrometer to measure the beam intensity and to calculate the delivered dose. On the other hand, the authors have irradiated EBT2 films, with 6-MV X rays, to get the dose response of EBT2 films for photons. The dose response curve for alpha particles shows an effect of polymerisation saturation compared with the dose response curve for photons.

82Sr purification procedure using Chelex-100 resin

(82)Rb is a positron-emitting radionuclide widely used in nuclear cardiology. One great advantage is its availability through a generator loaded with (82)Sr. (82)Sr can be produced in a high energy cyclotron by irradiating rubidium chloride target with proton beam. In this paper, we present an extensive study (elution profiles, effect of the elution flow rate) on the use of Chelex-100 resin and ammonia buffer. No significant effect of flow rate was evidenced between 1 and 10mL/min leading us to propose a purification process which can be easily automated.

Hemolysis induced by an extreme mountain ultra-marathon is not associated with a decrease in total red blood cell volume

Prolonged running is known to induce hemolysis. It has been suggested that hemolysis may lead to a significant loss of red blood cells; however, its actual impact on the erythrocyte pool is unknown. Here, we test the hypothesis that prolonged running with high hemolytic potential decreases total red blood cell volume (RCV). Hemolysis (n = 22) and RCV (n = 19) were quantified in ultra-marathon runners before and after a 166-km long mountain ultra-endurance marathon (RUN) with 9500 m of altitude gain/loss. Assessment of total hemoglobin mass (Hbmass) and RCV was performed using a carbon monoxide rebreathing technique. RUN induced a marked acute-phase response and promoted hemolysis, as shown by a decrease in serum haptoglobin (P < 0.05). Elevated serum erythropoietin concentration and reticulocyte count after RUN were indicative of erythropoietic stimulation. Following RUN, runners experienced hemodilution, mediated by a large plasma volume expansion and associated with a large increase in plasma aldosterone. However, neither Hbmass nor RCV were found to be altered after RUN. Our findings indicate that mechanical/physiological stress associated with RUN promotes hemolysis but this has no impact on total erythrocyte volume. We therefore suggest that exercise 'anemia' is entirely due to plasma volume expansion and not to a concomitant decrease in RCV.

One step purification process for no-carrier-added 64Cu produced using enriched nickel target

Copper-64 has found many applications in positron emission tomography (PET). Its half-life allows to use it for dosimetric studies associated to copper-67 targeted radiotherapy in cancer treatment. The use of 64Ni(p,n)64Cu nuclear reaction is known to produce 64Cu in large amount and with a high specific activity. In this study, targets were obtained by electroplating onto a gold backing and a typical target irradiation uses 200ߙnA, 17ߙMeV protons during 30ߙmin. After irradiation, pure copper-64 is obtained using only one chromatographic column. Nickel-64 is removed in a first elution step and cobalt isotopes in a second one. The extraction yield for copper-64 is 9±23% and nickel and cobalt impurities are under the detection limit. A recovery process of nickel-64 has also been developed.

Very compact external cavity diffraction-coupled tapered laser diodes

To maintain the same beam quality as that of a single emitter and to be close to diffraction limit, we have combined a phase corrected array, emitting at lambda = 975 nm, coherently using the Talbot effect. First, to improve the beam quality of the array, a phase correcting system was added. The FWHM divergences of the array (which is approximately the same as that of the single emitter since the emitters within the array are not optically coupled to each other) were reduced from 34 degrees to 0.17 degrees in the fast axis and from 3.5 degrees to 0.7 degrees in the slow axis at 6 A. Then, to be close to the diffraction limit, we have combined this corrected array coherently using the Talbot effect. We have obtained a quasi-monolobe slow axis far field profile for the in-phase mode with a central peak divergence of only 0.27 degrees at 1.5 A, 315 mW under cw operation, and of only 0.20 degrees at 2.5 A, 787 mW under pulsed operation. To our knowledge, this is the first demonstration of coherent coupling of a corrected tapered laser diode array in an external Talbot cavity.

Density matrix renormalization group approach for many-body open quantum systems

The density matrix renormalization group (DMRG) approach is extended to complex-symmetric density matrices characteristic of many-body open quantum systems. Within the continuum shell model, we investigate the interplay between many-body configuration interaction and coupling to open channels in case of the unbound nucleus (7)He. It is shown that the extended DMRG procedure provides a highly accurate treatment of the coupling to the nonresonant scattering continuum.

Distribution of Streptococcus pneumoniae serotypes responsible for penicillin resistance and the potential role of new conjugate vaccines in New Caledonia

Invasive pneumococcal disease is a significant cause of morbidity and mortality worldwide. The aim of this study was to establish the serotypes responsible for pneumococcal disease and the serotypes responsible for penicillin resistance in Noumea, New Caledonia. Isolates of Streptococcus pneumoniae from all body sites referred to the Microbiology Department of the Pasteur Institute in New Caledonia between May 1999 and May 2001 had serotyping and susceptibility testing performed. Basic demographic data on patients were also collected. A total of 298 isolates were included in the study. The most common serotypes were types 1 (20%), 23F (10%), 12F (8%), 19F (8%), and 6B (5%). The serotype distribution differed significantly with age, site of collection, and ethnicity. Overall, 280 of 298 (94%) of the isolates had serogroups that are included in the 23-valent vaccine. However, only 14 of 20 (70%) of the isolates associated with invasive disease from children younger than 5 years of age and 26 of 113 (23%) of invasive isolates from patients more than 5 years of age were included in the new 7-valent conjugate vaccine. Overall, reduced susceptibility to penicillin was found in 43 of 298 (14.4%) of the isolates, with 13% falling into the intermediate resistance category and only 5 (2%) being high-level resistant. A higher prevalence of penicillin resistance occurred in younger age groups and in European patients and involved specifically certain serotypes. The 7-valent conjugate pneumococcal vaccine has potential benefit for the New Caledonian population under 5 years of age and should be considered for future vaccines schedules.

Experimental study on a large animal model of a new thermoablation technique

BACKGROUND

A novel technique of thermoablation, using a microtube to deliver pulses of hot water vapour, was tested on a large animal model in order to evaluate its efficacy and potential adverse effects.

MATERIALS AND METHODS

The medical device consisted of a microtube extension connected to a hydropneumatic pump. Pulses of pure water were injected though the microtube where they were heated and delivered as vapour into the target zone. The method was tested on the liver of 12 healthy pigs, either during open surgery or percutaneously under ultrasounds.

RESULTS

The technique was efficient and well-tolerated by the animals. Large volumes of necrotic tissue were created in a significantly short time compared to concurrent thermoablative techniques.

CONCLUSION

Anticipating human application, this experimental study demonstrated a safe and efficient innovative thermoablation technique. The first human applications have been successfully performed and will be reported soon.

CBED and LACBED: characterization of antiphase boundaries

Convergent-beam electron diffraction (CBED) and large-angle convergent-beam electron diffraction (LACBED) techniques are well adapted to the characterization of several types of crystal defects. In fact, dislocations, grain boundaries and stacking faults have already been successfully characterized with these methods. In the present paper, we describe the CBED and LACBED characterization of another type of crystal defect showing a special interest in materials science: antiphase boundaries (APBs). The first part of the paper is devoted to the determination of the effects of antiphase boundaries on CBED and LACBED patterns that could be expected from a theoretical point of view. It indicates that the superlattice excess lines present on these patterns are split into two lines with equal intensity when the incident beam is located on an APB. In the second part, we experimentally test these theoretical predictions on a specimen showing two different known types of antiphase boundaries. In a third part we indicate how these methods could be used to identify unknown APBs in a specimen. Finally, the advantages and disadvantages of both methods for the characterization of antiphase boundaries are discussed.

Gamow shell model description of neutron-rich nuclei

This work presents the first continuum shell-model study of weakly bound neutron-rich nuclei involving multiconfiguration mixing. For the single-particle basis, the complex-energy Berggren ensemble representing the bound single-particle states, narrow resonances, and the nonresonant continuum background is taken. Our shell-model Hamiltonian consists of a one-body finite potential and a zero-range residual two-body interaction. It is demonstrated that the residual interaction coupling to the particle continuum is important; in some cases, it can give rise to the binding of a nucleus.

A DNA vaccine based on a shuffled E7 oncogene of the human papillomavirus type 16 (HPV 16) induces E7-specific cytotoxic T cells but lacks transforming activity

Vaccination with oncogene-derived DNA for anti-cancer treatment carries a risk of de-novo tumor induction triggered by the persisting recombinant DNA. We hypothesized that an oncoprotein whose primary sequence has been rearranged ('shuffled') to maintain all possible T cell epitopes still induces cytotoxic T cells against the authentic protein but is devoid of transforming properties. As a model antigen, we used the E7 oncoprotein of the human papillomavirus (HPV) type 16, the major cause of cervical cancer. We have generated an artificial E7 molecule in which four domains were rearranged and, in order to maintain all possible T cell epitopes, certain sequences were duplicated. Upon transfection of this shuffled E7 gene (E7SH) into RMA cells, presentation of an E7 Db-restricted T cell epitope was shown by an E7-specific CTL line in vitro. Immunization of C57BL/6 mice with E7SH DNA induced E7-specific CTL and also conveyed protection against E7-positive syngeneic tumor cells. No transforming activity of E7SH DNA in NIH3T3 cells was detected, as determined by focus formation, induction of S-phase under conditions of serum deprivation and degradation of endogenous pRB. Our results suggest that DNA shuffling may become a promising concept for DNA-based anti-cancer vaccines.

Study of neuromotor reaction times under the influence of thyrotropin-releasing hormone

Neuromotor reaction times (simple, choice, and decision) were measured when Thyrotropin-releasing hormone (TRH) was administered intravenously to nine healthy men in a double-blind study. Measurements were made of simple reaction time, choice reaction time, and decision time for each subject at various intervals over a 54-hr. period. Given the observed inherent interaction of the drug with the long time used (54 hr.), most analyses were conducted across separate time epochs. Injected subjects showed inhibition in the normal improvement of simple reaction time (which occurs with practice), and they reduced the time required to make a decision. Choice reaction time, however, remained unchanged across the drug-nondrug experimental conditions.

Effect of directional response variables on eye-hand reaction times and decision time

To determine if direction of response affects reaction time, we measured the time for hand response to a visual stimulus, using a sensitive, microprocessor-based testing device to determine simple reaction time (RT), choice RT, and decision time. Mean simple RT was 207 +/- 3.7 msec. (mean +/- SEM); mean choice RT was 268 +/- 4.2 msec; and mean decision time was 61 msec. No differences were noted for leftward versus rightward movements, or midline versus lateral movements. Choice RT increased by 1.49 msec./yr. of age. Simple RT increased significantly with age for the nondominant hand, but not for the dominant hand. Right-handed subjects were more rapid with the dominant hand for choice RT. We conclude that dominance of hand tested and test initiation mechanism have major effects, but direction of movement in the lateral plane has little effect on reaction time.