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Laser-driven deuterons generate neutrons with a mean energy of 2.5 MeV, through the 2 H(d,n) fusion reaction in a deuterated polyethylene (dPE) tablet. The deuterium ions are accelerated by 12 fs, 21 mJ laser pulses interacting with a 0.2 µm thin dPE foil at a peak intensity of 10 18 W/cm 2 . The laser was operated at 1 Hz repetition rate in bursts of 75 shots. The interaction was characterized and recorded for each laser shot. The ion spectra were measured in the forward and backward directions by Thomson ion spectrometers. Neutron events were detected by a time-of-flight (ToF) system consisting of four plastic scintillators positioned at various angles around the experimental chamber. The maximum cut-off energy of the forward accelerated protons and deuterons was close to 1.4 MeV and 1 MeV, while the mean values are 428 ± 63 keV and 433 ± 80 keV, respectively. Analysis of ToF distributions from 3128 shots resulted in an average yield of 1142 ± 59 neutrons per shot in the energy range of 1.5-4 MeV. The energy distribution of forward-directed neutrons peaks between 3 and 3.5 MeV. Angular dependence analysis showed a perpendicular minimum and a maximum along the deuteron beam, consistent with the expected distribution from the literature and our simulation results., (© 2024. The Author(s).)

The neutron-rich unbound fluorine isotope ^{30}F_{21} has been observed for the first time by measuring its neutron decay at the SAMURAI spectrometer (RIBF, RIKEN) in the quasifree proton knockout reaction of ^{31}Ne nuclei at 235  MeV/nucleon. The mass and thus one-neutron-separation energy of ^{30}F has been determined to be S_{n}=-472±58(stat)±33(sys)  keV from the measurement of its invariant-mass spectrum. The absence of a sharp drop in S_{n}(^{30}F) shows that the "magic" N=20 shell gap is not restored close to ^{28}O, which is in agreement with our shell-model calculations that predict a near degeneracy between the neutron d and fp orbitals, with the 1p_{3/2} and 1p_{1/2} orbitals becoming more bound than the 0f_{7/2} one. This degeneracy and reordering of orbitals has two potential consequences: ^{28}O behaves like a strongly superfluid nucleus with neutron pairs scattering across shells, and both ^{29,31}F appear to be good two-neutron halo-nucleus candidates.

Subjecting a physical system to extreme conditions is one of the means often used to obtain a better understanding and deeper insight into its organization and structure. In the case of the atomic nucleus, one such approach is to investigate isotopes that have very different neutron-to-proton (N/Z) ratios than in stable nuclei. Light, neutron-rich isotopes exhibit the most asymmetric N/Z ratios and those lying beyond the limits of binding, which undergo spontaneous neutron emission and exist only as very short-lived resonances (about 10 -21  s), provide the most stringent tests of modern nuclear-structure theories. Here we report on the first observation of 28 O and 27 O through their decay into 24 O and four and three neutrons, respectively. The 28 O nucleus is of particular interest as, with the Z = 8 and N = 20 magic numbers 1,2 , it is expected in the standard shell-model picture of nuclear structure to be one of a relatively small number of so-called 'doubly magic' nuclei. Both 27 O and 28 O were found to exist as narrow, low-lying resonances and their decay energies are compared here to the results of sophisticated theoretical modelling, including a large-scale shell-model calculation and a newly developed statistical approach. In both cases, the underlying nuclear interactions were derived from effective field theories of quantum chromodynamics. Finally, it is shown that the cross-section for the production of 28 O from a 29 F beam is consistent with it not exhibiting a closed N = 20 shell structure., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Antibiotic resistance is one of the major challenges in healthcare of our time. To meet this challenge, we designed and prepared guanidine and lipophilic guanidine derivatives of the glycopeptide antibiotic teicoplanin to armed them with activity against the most threatening nosocomial bacteria, multiresistant enterococci. From teicoplanin and its pseudoaglycone, a series of N-terminal guanidine derivatives have been prepared with free and amide C-terminal parts. Six aliphatic and aromatic lipophilic carbodiimides were prepared and used for the synthesis of lipophilic guanidine teicoplanin conjugates. All new N-terminal guanidine antibiotics showed high activity against a standard panel of Gram-positive bacteria. Four selected derivatives displayed excellent antibacterial activity against a series of nosocomial VanA Enterococcus faecium strains.

Excessive use of antibiotics contributes to the selection of resistant bacteria and intestinal colonization with multiresistant pathogens poses a risk factor for subsequent infections. The present study assessed vancomycin-resistant enterococci (VRE) carriage rates in patients admitted to our tertiary care hospital. Stool samples sent for routine culturing were screened with vancomycin containing solid or broth enrichment media. VRE isolates were identified with matrix-assisted laser desorption/ionization-time of flight mass spectrometry and antibiotic susceptibilities were tested by E-test. Vancomycin resistance genes were detected by polymerase chain reaction. Medical records of carriers were examined for suspected risk factors for colonization. Altogether 3025 stool specimens were analyzed. Solid media identified a VRE carriage rate of 2.2% while broth enrichment detected 5.8%. Seventy percent of the isolates were Enterococcus faecium. VanB genotype was detected in 38.2%, VanA in 37.3%, VanC1 in 22.6%, and VanC2 in 1.9%. All VRE were sensitive to linezolid, daptomycin, and tigecycline. Collective risk factors for carriage were diabetes, normal flora absence, Clostridioides difficile positivity, longer hospital stay, and advanced age. 78.5% of the carriers received antibiotic therapy which was metronidazole in most cases (47.3%). We recommend regular screening of risk groups such as patients with diabetes, history of recent hospitalization, or former C. difficile infection as an imperative step for preventing VRE dissemination.

Detailed spectroscopy of the neutron-unbound nucleus ^{28}F has been performed for the first time following proton/neutron removal from ^{29}Ne/^{29}F beams at energies around 230  MeV/nucleon. The invariant-mass spectra were reconstructed for both the ^{27}F^{(*)}+n and ^{26}F^{(*)}+2n coincidences and revealed a series of well-defined resonances. A near-threshold state was observed in both reactions and is identified as the ^{28}F ground state, with S_{n}(^{28}F)=-199(6)  keV, while analysis of the 2n decay channel allowed a considerably improved S_{n}(^{27}F)=1620(60)  keV to be deduced. Comparison with shell-model predictions and eikonal-model reaction calculations have allowed spin-parity assignments to be proposed for some of the lower-lying levels of ^{28}F. Importantly, in the case of the ground state, the reconstructed ^{27}F+n momentum distribution following neutron removal from ^{29}F indicates that it arises mainly from the 1p_{3/2} neutron intruder configuration. This demonstrates that the island of inversion around N=20 includes ^{28}F, and most probably ^{29}F, and suggests that ^{28}O is not doubly magic.

Objectives: Using dental Ti implants has become a well-accepted and used method for replacing missing dentition. It has become evident that in many cases peri-implant inflammation develops. The objective was to create and evaluate the antibacterial effect of silver nanoparticle (Ag-NP) coated Ti surfaces that can help to prevent such processes if applied on the surface of dental implants. Methods: Annealing I, Ag ion implantation by the beam of an Electron Cyclotron Resonance Ion Source (ECRIS), Ag Physical Vapor Deposition (PVD), Annealing II procedures were used, respectively, to create a safely anchored Ag-NP layer on 1x1 cm 2 Grade 2 titanium samples. The antibacterial effect was evaluated by culturing Staphylococcus aureus (ATCC 29213) on the surfaces of the samples for 8 hours, and comparing the results to that of glass as control and of pure titanium samples. Alamar Blue assay was carried out to check cytotoxicity. Results: It was proved that silver nanoparticles were present on the treated surfaces. The average diameter of the particles was 58 nm, with a 25 nm deviation and Gaussian distribution, the the filling factor was 25%. Antibacterial evaluation revealed that the nanoparticle covered samples had an antibacterial effect of 64.6% that was statistically significant. Tests also proved that the nanoparticles are safely anchored to the titanium surface and are not cytotoxic. Conclusion: Creating a silver nanoparticle layer can be an option to add antibacterial features to the implant surface and to help in the prevention of peri-implant inflammatory processes. Recent studies demonstrated that silver nanoparticles can induce pathology in mammal cells, thus safe fixation of the particles is essential to prevent them from getting into the circulation., Competing Interests: The authors report no conflicts of interest in this work.

New rotational bands built on the ν(h_{11/2}) configuration have been identified in ^{105}Pd. Two bands built on this configuration show the characteristics of transverse wobbling: the ΔI=1 transitions between them have a predominant E2 component and the wobbling energy decreases with increasing spin. The properties of the observed wobbling bands are in good agreement with theoretical results obtained using constrained triaxial covariant density functional theory and quantum particle rotor model calculations. This provides the first experimental evidence for transverse wobbling bands based on a one-neutron configuration, and also represents the first observation of wobbling motion in the A∼100 mass region.

Although vanA carrying Enterococcus faecium human clinical isolates have been rarely found in Hungary before 2012, they have been detected in continuously increasing numbers since then. To identify factors associated with their dissemination, we investigated the clonal relatedness and plasmids of 30 vanA carrying E. faecium isolates originating from different Hungarian healthcare institutions from 2012 to 2014. Molecular typing of the isolates (n = 30) was performed with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, Tn1546 polymerase chain reaction mapping, plasmid restriction fragment length polymorphism analysis, and sequencing. A single Tn1546 variant was detected in all of the isolates. It harbored IS1251 in the vanS-vanH intergenic region, had an entire deletion of the transposase gene and a partial deletion of the resolvase gene, and was located on a pRUM-like plasmid. Based on PFGE, the isolates could be grouped into 13 pulsotypes. Representative strains of these pulsotypes belonged to ST17, ST18, ST80, ST117, and ST203, which are known to be part of the hospital-adapted clades. The increase in the number of vanA carrying E. faecium clinical isolates in Hungary could be explained by the dissemination of pRUM-like vancomycin resistance plasmids in hospital-adapted clonal lineages.

Objectives: The aim of our study was to characterize and elicit the genetic relatedness of emerging vancomycin-resistant enterococci (VRE) isolated between 2012 and 2015 at a teaching hospital in Debrecen, Hungary., Results: Altogether 43 nonduplicate vancomycin-resistant Enterococcus faecium (VREfm) clinical isolates were obtained. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used for species identification. Isolates showed 100% resistance to ampicillin and ciprofloxacin while 81.4% were resistant to gentamicin. PCR analysis revealed the presence of VanB in 40 and VanA in 3 isolates. Among ace, agg, and esp virulence genes only esp was found in seven cases. Modified microtiter-plate test showed 13 weak and 4 moderate biofilm producer isolates. Pulsed-field gel electrophoresis revealed nine pulsotypes. According to multilocus sequence typing all of the tested isolates belonged to clonal complex 17 (CC17)., Conclusions: We report on the alarming emergence of multidrug-resistant VREfm belonging to CC17 at a tertiary hospital in Eastern Hungary. This is the first report of sequence types 412 and 364 from this region. Although outbreak did not occur the increasing prevalence of VREfm is of concern and dissemination must be prevented with proper infection control measures and regular VRE screening.

The ^{54}Fe nucleus was populated from a ^{56}Fe beam impinging on a Be target with an energy of E/A=500  MeV. The internal decay via γ-ray emission of the 10^{+} metastable state was observed. As the structure of this isomeric state has to involve at least four unpaired nucleons, it cannot be populated in a simple two-neutron removal reaction from the ^{56}Fe ground state. The isomeric state was produced in the low-momentum (-energy) tail of the parallel momentum (energy) distribution of ^{54}Fe, suggesting that it was populated via the decay of the Δ^{0} resonance into a proton. This process allows the population of four-nucleon states, such as the observed isomer. Therefore, it is concluded that the observation of this 10^{+} metastable state in ^{54}Fe is a consequence of the quark structure of the nucleons.

Listeria monocytogenes is a foodborne pathogen, and the detection and differentiation of this bacterium from the nonpathogenic Listeria species are of great importance to the food industry. Differentiation of Listeria species is very difficult, even with the sophisticated MALDI-TOF MS technique because of the close genetic relationship of the species and the usual gene transfer. The present paper emphasizes the difficulties of the differentiation through the standardized detection and confirmation according to ISO 11290-1:1996 and basic available L. monocytogenes detection methods and tests (such as API Listeria test, MALDI-TOF MS analysis, and hly gene PCR). With the increase of reports on the pathogenesis of atypical Listeria strains in humans, the significance of species level determination has become questionable, especially in food quality control, and the detection of pathogenic characteristics seems to be more relevant.

With the increasing emergence of antibiotic resistances old antibiotics became a valuable source to find agents suitable to address this problem. More than 20 years after the last report, our purpose was to re-evaluate the in vitro antibacterial activity of the topical agent primycin against current important bacterial pathogens. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of primycin were tested in comparison with agents widely applied topically, and with those of mupirocin and vancomycin, the topical and the non-topical gold-standard anti-MRSA agents. Primycin was ineffective (MIC>64 μg/ml) against all the Gram-negative isolates tested. On the other hand, all the tested Gram-positive isolates were susceptible with MIC90 values of 0.06 μg/ml for staphylococci and 0.5-1 μg/ml for enterococci, streptococci, and P. acnes isolates, including all the multiresistant strains. Against MRSA isolates primycin showed slightly higher activity than mupirocin, and inhibited the mupirocin-resistant strains also. MBC90 values ranged from 0.25 to 2 μg/ml for the investigated Gram-positive species. The bactericidal effect proved to be concentration-dependent in time-kill experiments. Spontaneous resistant mutants did not emerge in single-step mutation experiments and the resistance development was very slow by serial passaging. Passaged S. aureus strains showing increased primycin MIC values exhibited elevated vancomycin and daptomycin MIC values also. Though elucidation of the mechanisms behind warrants further investigations, these correlations can be related to development of vancomycin-intermediate phenotype. From the point of view of medical practice it is noteworthy that the increased primycin MIC values remained far below the concentration accessible by local application of the agent. These data make primycin a remarkable object of further investigations as well as a promising candidate for topical application against multiresistant Gram-positive pathogens., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Search for a new kind of superfluidity built on collective proton-neutron pairs with aligned spin is performed studying the Gamow-Teller decay of the T=1, J(π)=0+ ground state of (62)Ge into excited states of the odd-odd N=Z nucleus (62)Ga. The experiment is performed at GSI Helmholtzzentrum für Shwerionenforshung with the (62)Ge ions selected by the fragment separator and implanted in a stack of Si-strip detectors, surrounded by the RISING Ge array. A half-life of T1/2=82.9(14)  ms is measured for the (62)Ge ground state. Six excited states of (62)Ga, populated below 2.5 MeV through Gamow-Teller transitions, are identified. Individual Gamow-Teller transition strengths agree well with theoretical predictions of the interacting shell model and the quasiparticle random phase approximation. The absence of any sizable low-lying Gamow-Teller strength in the reported beta-decay experiment supports the hypothesis of a negligible role of coherent T=0 proton-neutron correlations in (62)Ga.

A measurement of the reduced transition probability for the excitation of the ground state to the first 2+ state in 104Sn has been performed using relativistic Coulomb excitation at GSI. 104Sn is the lightest isotope in the Sn chain for which this quantity has been measured. The result is a key point in the discussion of the evolution of nuclear structure in the proximity of the doubly magic nucleus 100Sn. The value B(E2; 0+ → 2+) = 0.10(4) e2b2 is significantly lower than earlier results for 106Sn and heavier isotopes. The result is well reproduced by shell model predictions and therefore indicates a robust N = Z = 50 shell closure.

The 02(+) state in 34Si has been populated at the GANIL-LISE3 facility through the β decay of a newly discovered 1(+) isomer in 34Al of 26(1) ms half-life. The simultaneous detection of e(+)e(-) pairs allowed the determination of the excitation energy E(02(+))=2719(3)  keV and the half-life T(1/2)=19.4(7) ns, from which an electric monopole strength of ρ(2)(E0)=13.0(0.9)×10(-3) was deduced. The 2(1)(+) state is observed to decay both to the 0(1)(+) ground state and to the newly observed 0(2)(+) state [via a 607(2) keV transition] with a ratio R(2(1)(+)→0(1)(+)/2(1)(+)→0(2)(+))=1380(717). Gathering all information, a weak mixing with the 0(1)(+) and a large deformation parameter of β=0.29(4) are found for the 0(2)(+) state, in good agreement with shell model calculations using a new SDPF-U-MIX interaction allowing np-nh excitations across the N=20 shell gap.

Risk factors for invasive infections by heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) may involve resistance to opsonophagocytosis and bacterial killing. hVISA strains typically have a thickened cell wall with altered peptidoglycan cross-linking. To determine whether hVISA may be endowed with an increased resistance to phagocytosis, this study assessed the characteristics of uptake and killing by granulocytes of three hVISA strains. All isolates were analysed by multilocus sequence typing and staphylococcal chromosome cassette mec typing. One of the strains belonged to the Hungarian meticillin-resistant S. aureus (MRSA) clone ST239-MRSA-III and the other two to the New York/Japan MRSA clone ST5-MRSA-II. In the presence of 10 % normal serum, the extent of phagocytosis and killing by blood granulocytes was equivalent for hVISA, MRSA and meticillin-sensitive S. aureus (MSSA) strains. Using granulocytes and serum from one patient who survived hVISA infection, the rate of phagocytosis and killing was also found to be comparable to that by control cells in the presence of 10 % serum. However, phagocytosis and killing of hVISA and MRSA (ATCC 25923) strains by normal granulocytes was markedly decreased in the presence of low concentrations (1 and 2.5 %) of serum from the patient who survived hVISA infection compared with that found with normal human serum. These data suggest that hVISA and MRSA isolates may be more resistant to opsonophagocytosis and bacterial killing than MSSA isolates, at least in some cases.

Vancomycin-resistant enterococci (VRE) are common nosocomial pathogens; however, until now they have been rarely encountered in Hungary. In the present study, we investigated the prevalence of VRE in the teaching hospitals of the University of Debrecen. Of 7,271 Enterococcus-containing clinical samples collected between 2004 and 2009, we identified 16 VRE. Species-specific polymerase chain reaction was used to detect Enterococcus faecalis, Enterococcus faecium, Enterococcus casseliflavus, and Enterococcus gallinarum. Multiplex polymerase chain reaction was performed to identify the vancomycin resistance genes: vanA, vanB, vanC1/C2, vanD, vanE, and vanG. Restriction digestion with SalI and HindIII was introduced to differentiate the vanC1 and vanC2 genes from each other. Genetic relationships between the strains were investigated by pulsed-field gel electrophoresis. Overall, we identified the vanC1 resistance gene in 14 E. gallinarum and the vanC2 resistance gene in two E. casseliflavus strains. Except for two samples, the isolates had different pulsed-field gel electrophoresis types, suggesting sporadic emergence of the resistant bacteria. In addition, antibiotic resistance profile was determined by E-test. Three E. gallinarum strains proved to be resistant to gentamicin because of the presence of the aacA-aphD gene. Although the prevalence of VRE in Debrecen is rather low, the appearance of multiple resistances is of concern.

Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing, in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus (92)Pd. Gamma rays emitted following the (58)Ni((36)Ar,2n)(92)Pd fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution γ-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction. We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.

The structure of 44S has been studied by using delayed γ and electron spectroscopy. The decay rates of the 02+ isomeric state to the 2(1)+ and 0(1)+ states, measured for the first time, lead to a reduced transition probability B(E2: 2(1)+→0(2)+)=8.4(26) e(2) fm4 and a monopole strength ρ2(E0: 0(2)+→0(1)+)=8.7(7)×10(-3). Comparisons to shell model calculations point towards prolate-spherical shape coexistence, and a two-level mixing model is used to extract a weak mixing between the two configurations.

The performance of the VITEK 2 System (bioMérieux) version 3.01 software was compared to that of the E-test (AB Biodisk, Solna, Sweden) for antibiotic susceptibility testing of 17 clinical isolates of vancomycin resistant enterococcus (VRE). Antibiotic Susceptibility Testing (AST) by VITEK 2 produced 10 minor (59%) errors, resulting in false phenotypes. Reporting of vancomycin resistance in enterococcal strains has enormous therapeutic and epidemiological consequences. Therefore, at laboratories using automated systems (e.g. VITEK 2) for routine microbiological susceptibility testing data must be confirmed by independent validated methods, e.g. E-test, or microdilution.

The purpose of this study was to characterise methicillin-resistant Staphylococcus aureus (MRSA) strains isolated in 2005 at the university hospitals of Debrecen, Hungary. Three hundred and thirty-nine MRSA strains were isolated from 102 patients at 18 different clinics. Their sensitivity to oxacillin and ten other antibiotics was determined. For genotypic analysis, phage typing and pulsed-field gel electrophoresis (PFGE) was performed. The rate of MRSA strains increased to 7.2% in 2005, especially at the clinics of surgery, pulmonology and paediatrics. No vancomycin- or teicoplanin-resistant strains were found. The resistance to erythromycin, clindamycin and ciprofloxacin was nearly 100% and multi-resistance was very frequent. Fifty-eight percent of the isolates belonged to mixed phage types and 8% was non-typable. One PFGE clone contained 58.2% of all strains and two further major clones were found at a separately located clinical block, indicating intra-hospital spread. We can conclude that MRSA exhibits an increasing nosocomial problem also in Hungary.

The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from the fragmentation of secondary beams of (42,44)S at 39A MeV. The low 2(+) energy of (42)Si, 770(19) keV, together with the level schemes of (41,43)P, provides evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that (42)Si is best described as a well-deformed oblate rotor.

Neutron single particle energies have been measured in 23O using the 22O(d,p)23O*-->22O+n process. The energies of the resonant states have been deduced to be 4.00(2) MeV and 5.30(4) MeV. The first excited state can be assigned to the nu d3/2 single particle state from a comparison with shell model calculations. The measured 4.0 MeV energy difference between the nu s1/2 and nu d3/2 states gives the size of the N=16 shell gap which is in agreement with the recent USD05 ("universal" sd from 2005) shell model calculation, and is large enough to explain the unbound nature of the oxygen isotopes heavier than A=24. The resonance detected at 5.3 MeV can be assigned to a state out of the sd shell model space. Its energy corresponds to a approximately 1.3 MeV sized N=20 shell gap, therefore, the N=20 shell closure disappears at Z=8 in agreement with Monte Carlo shell model calculations using SDPF-M interaction.

The N = 28 shell closure has been investigated via the 46Ar(d,p)47Ar transfer reaction in inverse kinematics. Energies and spectroscopic factors of the neutron p(3/2), p(1/2), and f(5/2) states in 47Ar were determined and compared to those of the 49Ca isotone. We deduced a reduction of the N = 28 gap by 330(90) keV and spin-orbit weakenings of approximately 10(2) and 45(10)% for the f and p states, respectively. Such large variations for the f and p spin-orbit splittings could be accounted for by the proton-neutron tensor force and by the density dependence of the spin-orbit interaction, respectively. This contrasts with the picture of the spin-orbit interaction as a surface term only.

The reduced transition probabilities B(E2;0(+) --> 2(+)(1)) of the neutron-rich (74)Zn and (70)Ni nuclei have been measured by Coulomb excitation in a (208)Pb target at intermediate energy. These nuclei have been produced at Grand Accélérateur National d'Ions Lourds via interactions of a 60A MeV (76)Ge beam with a Be target. The B(E2) value for (70)Ni(42) is unexpectedly large, which indicates that neutrons added above N=40 strongly polarize the Z=28 proton core. In the Zn isotopic chain, the steep rise of B(E2) values beyond N=40 continues up to (74)Zn(44). The enhanced proton core polarization in (70)Ni is attributed to the monopole interaction between the neutron in the g(9/2) and protons in the f(7/2) and f(5/2) spin-orbit partner orbitals. This interaction could result in a weakening of magicity in (78)Ni(50).

This Letter reports on the (1)H((28)Ne, (28)Ne) and (1)H((28)Ne, (27)Ne) reactions studied at intermediate energy using a liquid hydrogen target. From the cross section populating the first 2(+) excited state of (28)Ne, and using the previously determined BE(2) value, the neutron quadrupole transition matrix element has been calculated to be M(n)=13.8 +/- 3.7 fm(2). In the neutron knockout reaction, two low-lying excited states were populated in (27)Ne. Only one of them can be interpreted by the sd shell model while the additional state may intrude from the fp shell. These experimental observations are consistent with the presence of fp shell configurations at low excitation energy in (27,28)Ne nuclei caused by a vanishing N=20 shell gap at Z=10.

The electric quadrupole transition from the first 2(+) state to the ground 0(+) state in 16C is studied through measurement of the lifetime by a recoil shadow method applied to inelastically scattered radioactive 16C nuclei. The measured mean lifetime is 77+/-14(stat)+/-19(syst) ps. The central value of mean lifetime corresponds to a B(E2;2+(1)-->0(+)) value of 0.63e(2) fm(4), or 0.26 Weisskopf units. The transition strength is found to be anomalously small compared to the empirically predicted value.

The neutron-rich (66,68)Ni have been produced at GANIL via interactions of a 65.9A MeV 70Zn beam with a 58Ni target. Their reduced transition probability B(E2;0(+)(1)-->2+) has been measured for the first time by Coulomb excitation in a (208)Pb target at intermediate energy. The B(E2) value for (68)Ni(40) is unexpectedly small. An analysis in terms of large scale shell model calculations stresses the importance of proton core excitations to reproduce the B(E2) values and indicates the erosion of the N = 40 harmonic-oscillator subshell by neutron-pair scattering.