Evidence of a Near-Threshold Resonance in

A narrow near-threshold proton-emitting resonance (E_{x}=11.4 MeV, J^{π}=1/2^{+}, and Γ_{p}=4.4 keV) was directly observed in ^{11}B via proton resonance scattering. This resonance was previously inferred in the ß-delayed proton emission of the neutron halo nucleus ^{11}Be. The good agreement between both experimental results serves as a ground to confirm the existence of such exotic decay and the particular behavior of weakly bound nuclei coupled to the continuum. R-matrix analysis shows a sizable partial decay width for both, proton and α (Γ_{α}=11 keV) emission channels.

Microscopic Structure of the Low-Energy Electric Dipole Response of

The microscopic structure of the low-energy electric dipole response, commonly denoted as pygmy dipole resonance (PDR), was studied for ^{120}Sn in a ^{119}Sn(d,pγ)^{120}Sn experiment. Unprecedented access to the single-particle structure of excited 1^{-} states below and around the neutron-separation threshold was obtained by comparing experimental data to predictions from a novel theoretical approach. The novel approach combines detailed structure input from energy-density functional plus quasiparticle-phonon model theory with reaction theory to obtain a consistent description of both the structure and reaction aspects of the process. The presented results show that the understanding of one-particle-one-hole structures of the 1^{-} states in the PDR region is crucial to reliably predict properties of the PDR and its contribution to nucleosynthesis processes.

Accessing the Single-Particle Structure of the Pygmy Dipole Resonance in

New experimental data on the neutron single-particle character of the Pygmy Dipole Resonance (PDR) in ^{208}Pb are presented. They were obtained from (d,p) and resonant proton scattering experiments performed at the Q3D spectrograph of the Maier-Leibnitz Laboratory in Garching, Germany. The new data are compared to the large suite of complementary, experimental data available for ^{208}Pb and establish (d,p) as an additional, valuable, experimental probe to study the PDR and its collectivity. Besides the single-particle character of the states, different features of the strength distributions are discussed and compared to large-scale shell model (LSSM) and energy-density functional plus quasiparticle-phonon model theoretical approaches to elucidate the microscopic structure of the PDR in ^{208}Pb.

Erratum: Direct Observation of Proton Emission in

This corrects the article DOI: 10.1103/PhysRevLett.123.082501.

Towards Neutron Capture on Exotic Nuclei: Demonstrating (d,pγ) as a Surrogate Reaction for (n,γ).

The neutron-capture reaction plays a critical role in the synthesis of the elements in stars and is important for societal applications including nuclear power generation and stockpile-stewardship science. However, it is difficult-if not impossible-to directly measure neutron capture cross sections for the exotic, short-lived nuclei that participate in these processes. In this Letter we demonstrate a new technique which can be used to indirectly determine neutron-capture cross sections for exotic systems. This technique makes use of the (d,p) transfer reaction, which has long been used as a tool to study the structure of nuclei. Recent advances in reaction theory, together with data collected using this reaction, enable the determination of neutron-capture cross sections for short-lived nuclei. A benchmark study of the ^{95}Mo(d,p) reaction is presented, which illustrates the approach and provides guidance for future applications of the method with short-lived isotopes produced at rare isotope accelerators.

Direct Observation of Proton Emission in

The elusive ß^{-}p^{+} decay was observed in ^{11}Be by directly measuring the emitted protons and their energy distribution for the first time with the prototype Active Target Time Projection Chamber in an experiment performed at ISAC-TRIUMF. The measured ß^{-}p^{+} branching ratio is orders of magnitude larger than any previous theoretical model predicted. This can be explained by the presence of a narrow resonance in ^{11}B above the proton separation energy.

Structure and Reactions of

The exotic nucleus ^{11}Be has been extensively studied and much experimental information is available on the structure of this system. We treat, within the framework of renormalized nuclear field theory in both configuration and 3D space, the mixing of bound and continuum single-particle states through the coupling to collective vibrations of the ^{10}Be core. We also take care of the Pauli principle acting not only between the single valence particle explicitly considered and those participating in the collective states, but also between fermions involved in two-phonon virtual states dressing the single-particle motion. In this way, it is possible to simultaneously and quantitatively account for the energies of the 1/2^{+}, 1/2^{-} low-lying states, the centroid and line shape of the 5/2^{+} resonance and the one-nucleon stripping and pickup absolute differential cross sections involving ^{11}Be as either target or residual nucleus. Also for the dipole transition connecting the 1/2^{+} and 1/2^{-} parity inverted levels as well as the isotopic shift of the charge radius. Theory provides a unified and exhaustive nuclear structure and reaction characterization of the many-body effects which are at the basis of this paradigmatic one-neutron halo system.

Large Longitudinal Spin Alignment of Excited Projectiles in Intermediate Energy Inelastic Scattering.

We study the sequential breakup of E/A=24.0 MeV ^{7}Li projectiles excited through inelastic interactions with C, Be, and Al target nuclei. For peripheral events that do not excite the target, we find very large spin alignment of the excited ^{7}Li projectiles longitudinal to the beam axis. This spin alignment is independent of the target used, and we propose a simple alignment mechanism that arises from an angular-momentum-excitation-energy mismatch. This mechanism is independent of the potential used for scattering and should be present in many scattering experiments.

Is there an association between prior anti-inflammatory drug exposure and occurrence of peritonsillar abscess (PTA)? A national multicenter prospective observational case-control study.

The aim of this study was to evaluate whether recent systemic anti-inflammatory agents (AIAs) exposure in patients with sore throat managed with or without antibiotic therapy influenced the risk of peritonsillar abscess (PTA). We conducted a multicenter case-control study in 13 French university hospitals in 2009-2012 comparing patients admitted with PTA to matched controls: patients with sore throat but without PTA who were followed up for 10 days after visiting their primary-care physician. In the multivariate stepwise logistic regression model comparing 120 cases with PTA to 143 controls, factors significantly associated with PTA were male gender (odds ratio [OR], 2.0; p = 0.03), smoking (OR, 2.0; p = 0.03), and prior self-medication with systemic AIAs (OR, 3.5; p = 0.01). Topical treatment was associated with significant protection against PTA (OR, 0.3; p < 0.001). In conclusion, self-medication with systemic AIAs appears to be an independent factor associated with the occurrence of PTA. This is an important message as non-steroidal AIAs access is favored by their over-counter availability in pharmacies. This finding must be interpreted with caution due to the study design and a prospective, randomized study is needed to substantiate these possible causal risk factors.

New in vitro and in vivo models to evaluate antibiotic efficacy in Staphylococcus aureus prosthetic vascular graft infection.

OBJECTIVE: Prosthetic vascular graft infection (PVGI) is an emerging disease, mostly caused by staphylococci, with limited data regarding efficacy of current antistaphylococcal agents. We aimed to assess the efficacy of different antibiotic regimens. METHODS: Six different strains of MSSA and MRSA were used. We compared results of minimal biofilm inhibitory and eradicating concentrations (MBICs and MBECs) obtained with a Calgary Biofilm Pin Lid Device (CBPD) with those yielded by an original Dacron(®)-related minimal inhibitory and eradicating concentration measure model. We then used a murine model of Staphylococcus aureus vascular prosthetic material infection to evaluate efficacy of different antibiotic regimens: vancomycin and daptomycin combined or not with rifampicin for MRSA and the same groups with cloxacillin and cloxacillin combined with rifampicin for MSSA. RESULTS: We demonstrated that classical measures of MBICs and MBECs obtained with a CPBD could overestimate the decrease in antibiotic susceptibility in material-related infections and that the nature of the support used might influence the measure of biofilm susceptibility, since results yielded by our Dacron(®)-related minimal eradicating assay were lower than those found with a plastic device. In our in vivo model, we showed that daptomycin was significantly more bactericidal than comparators for some strains of MRSA or MSSA but not for all. For the majority of strains, it was as efficient as comparators. The addition of rifampicin to daptomycin did not enhance daptomycin efficacy. CONCLUSIONS: Despite the heterogeneity of results according to bacterial strains, these innovative models represent an option to better evaluate the in vitro efficacy of antibiotics on Dacron(®)-related biofilm S. aureus infections, and to screen different antibiotic regimens in a mouse model of PVGIs.

Peritonsillar abscess (PTA): clinical characteristics, microbiology, drug exposures and outcomes of a large multicenter cohort survey of 412 patients hospitalized in 13 French university hospitals.

The aim of this study was to describe the epidemiology of hospitalized patients with peritonsillar abscess (PTA). We conducted a multicenter survey in 13 French university hospitals in 2009-2012 describing 412 patients. Median age was 29 year (range, 2-84) and current smoking habit was reported by 177 (43 %) patients. Most of the patients (92 %) had consulted a physician for sore throat within 10 days before admission for PTA diagnosis. Additional symptoms such as visible tonsil abnormalities (83 %), tender cervical adenopathy (57 %) and fever ≥ 38.5 °C (53 %) were also reported. A total of 65 % patients (269/412) reported recent systemic anti-inflammatory agents (AIAs) exposure by medical prescription (70 %), self-medication (22 %), or both (8 %); 61 % and 27 % reported recent exposure to antibiotic and topical treatments for sore throat, respectively. Non-steroidal AIAs were used most often (45 %), particularly arylpropionic derivatives. A rapid diagnosis antigen test (RDT) for Streptococcus pyogenes was performed in 70 (17 %) patients and was positive in 17 (24 %), of whom 9 (53 %) were exposed to AIAs and 14 (82 %) to antibiotics. To treat PTA, antibiotic therapy was given to 392 (95 %) patients. Of 333 antibiotic prescriptions, amoxicillin-clavulanic acid and metronidazole were the most prescribed antibiotics (42 and 17 %, respectively). Surgical drainage of the abscess was performed in 119 (29 %) cases and tonsillectomy in 75 (18 %) cases. The clinical outcome was favorable during the hospital stay in 404 (98 %) patients. In conclusion, patients with sore throat are often exposed to AIAs before PTA diagnosis, and antibiotic prescription was not often based on the RDT positivity.

Cooper pair transfer in nuclei.

The second-order distorted wave Born approximation implementation of two-particle transfer direct reactions which includes simultaneous and successive transfer, properly corrected by non-orthogonality effects, is tested with the help of controlled nuclear structure and reaction inputs against data spanning the whole mass table, and showed to constitute a quantitative probe of nuclear pairing correlations.

Recent changes in bacteremia in patients with cancer: a systematic review of epidemiology and antibiotic resistance.

Bacteremia remains a major cause of life-threatening complication in patients with cancer. Significant changes in the spectrum of microorganisms isolated from blood culture have been reported in cancer patients over the past years. The aim of our systematic review was to inventory the recent trends in epidemiology and antibiotic resistance of microorganisms causing bacteremia in cancer patients. Data for this review was identified by searches of Medline, Scopus and Cochrane Library for indexed articles and abstracts published in English since 2008. The principal search terms were: "antimicrobial resistance", "bacteremia", "bacterial epidemiology", "bloodstream infection", "cancer patients", "carbapenem resistance", "Escherichia coli resistance", "extended-spectrum ß-lactamase producing E. coli", "febrile neutropenia", "fluoroquinolone resistance", "neutropenic cancer patient", "vancomycin-resistant Enterococcus", and "multidrug resistance". Boolean operators (NOT, AND, OR) were also used in succession to narrow and widen the search. Altogether, 27 articles were selected to be analyzed in the review. We found that Gram-negative bacteria were the most frequent pathogen isolated, particularly in studies with minimal use of antibiotic prophylaxis. Another important trend is the extensive emergence of antimicrobial-resistant strains associated with increased risk of morbidity, mortality and cost. This increasing incidence of antibiotic resistance has been reported in Gram-negative bacteria as well as in Gram-positive bacteria. This exhaustive review, reporting the recent findings in epidemiology and antibiotic resistance of bacteremia in cancer patients, highlights the necessity of local continuous surveillance of bacteremia and stringent enforcement of antibiotic stewardship programs in cancer patients.

A delivery system of linezolid to enhance the MRSA osteomyelitis prognosis: in vivo experimental assessment.

Staphylococcus aureus, a major responsible microorganism of osteomyelitis, represents a challenge to treat because of the poor penetration of antibiotics in bone and increasing minimum inhibitory concentrations (MICs) to glycopeptides. The calcium-deficient apatites (CDA), closer to the biological components found in bone and other calcified tissues, have osteoconductive properties. So, to process severe osseous infections, CDA can be used to deliver in the infectious site antibiotics like linezolid. The acute experimental osteomyelitis due to methicillin-resistant Staphylococcus aureus (MRSA) was induced in rabbit's femurs and surgery mimicking human procedures was performed at day three after inoculation. Animals were randomly assigned to treatment groups: L((IV)) [4-day linezolid IV infusion, human-equivalent dose of 10 mg/kg/12 h], L((CDA50%)) (100 mg CDA with linezolid 500 µg/mg) and L((CDA50%)) + L((IV)). Surviving bacteria were counted in bone marrow (BM) and bone (Bo) at day 3 (before treatment), day 7 (4-day treatment) or day 17 (14-day treatment). L(iv) was effective after a 4-day treatment with a log(10)CFU/g decrease of -2.63 ± 1.92 and -2.17 ± 1.58 in bone marrow and bone, respectively. CDA loaded with linezolid enhance the efficacy of the IV linezolid regimen by more than one log(10)CFU/g.

Why is antimicrobial de-escalation under-prescribed for urinary tract infections?

PURPOSE: To assess the frequency of de-escalation in inpatients treated for community-acquired urinary tract infection and the frequency of conditions legitimating not de-escalating therapy. METHODS: A retrospective study of inpatients (age >15 years) at a large academic hospital who were empirically treated for urinary tract infections due to Escherichia coli susceptible to at least one of the following antibacterial agents: amoxicillin, co-amoxiclav, and cotrimoxazole. De-escalation was defined as the replacement of the empirical broad-spectrum therapy by amoxicillin, co-amoxiclav, or cotrimoxazole. RESULTS: Eighty patients were included. De-escalation was prescribed for 32 of 69 patients for whom it was possible from both a bacteriological and clinical point of view (46 %, 95 % CI, 34-59 %). Initial treatment was switched to amoxicillin (n = 21), co-amoxiclav (n = 2), or cotrimoxazole (n = 8). Thirteen conditions justifying not de-escalating antibacterial therapy were detected in 11 of 48 patients who were not de-escalated (23 %, 95 % CI, 12-37 %): shock, n = 5; renal abscess, n = 1; obstructive uropathy, n = 4; bacterial resistance or clinical contraindication to both cotrimoxazole and ß-lactams, n = 3. CONCLUSIONS: De-escalation is under-prescribed for urinary tract infections. Omission of de-escalation is seldom legitimate. Interventions aiming to de-escalate antibacterial therapy for UTIs should be actively implemented.

Antenatal phosphodiesterase 4 inhibition restores postnatal growth and pulmonary development in a model of chorioamnionitis in rabbits.

Chorioamnionitis is implicated in the pathophysiology of bronchopulmonary disease, and the associated inflammatory response is responsible for adverse effects on alveolar development. The aim of this work was to analyze the effects of a phosphodiesterase 4 (PDE4)-selective inhibitor, rolipram (a modulator of the inflammatory response), in an experimental model of chorioamnionitis on pulmonary development and on the processes of infection and inflammation. Rabbit mothers were assigned to four groups: 1) saline serum inoculation (controls); 2) Escherichia coli intrauterine inoculation (C+); 3) rolipram infusion (R+); and 4) E. coli inoculation + rolipram infusion (C+R+). High rates of morbility and mortality were noticed in mothers and pups (5 of 13 pregnant rabbits in groups with rolipram). Alveolar development, inflammation, and infection were analyzed in pups at day 0 and day 5. At day 0, in the context of chorioamnionitis, rolipram significantly decreased birth weight (p < 0.01) relative to that of controls (p < 0.05). At day 5, weight normalized in group C+R+ but not in group C+ relative to controls (p < 0.001); moreover, alveolar airspace volume was preserved in group C+R+ but not in group C+ (p < 0.05). Interstitial volume decreased in group C+ versus controls (p < 0.05) but was preserved in group C+R+. Specific alveolar area was not significantly modified by rolipram. No significant difference was found concerning bronchoalveolar lavage cellularity, and all blood cultures remained sterile. In this model of impaired alveologenesis, rolipram significantly preserved specific alveolar density. However, PDE4 inhibition induced antenatal fetal demise and growth retardation.

The optimal aminoglycoside and its dosage for the treatment of severe Enterococcus faecalis infection. An experimental study in the rabbit endocarditis model.

Aminoglycosides are recommended for the treatment of Enterococcus faecalis infections, especially in severe and bacteremic infection. However, the optimal aminoglycoside or the optimal dosage remains uncertain. This study aimed to compare the activity of four aminoglycosides against E. faecalis (gentamicin, netilmicin, tobramycin, and amikacin) and two dosages of gentamicin. One clinical strain of E. faecalis was used to induce aortic endocarditis in the study rabbits. Each aminoglycoside was infused daily over 3 days with a computer-regulated flow simulating human pharmacokinetics of 15 mg/kg/day for amikacin, 6 mg/kg/day for netilmicin, and 3 mg/kg/day for gentamicin and tobramycin. Additionally, two dosages of gentamicin (simulating 3 or 6 mg/kg/day) were compared over 1 or 3 days of treatment. The in vivo efficacy was assessed according to the bacterial count in vegetations, in comparison with a control group. Of the four aminoglycosides tested, only gentamicin and netilmicin showed significant antibacterial efficacy after 3 days of treatment. After only 1 day of treatment, the high dosage of gentamicin (6 mg/kg/day) was more effective than the standard dosage (3 mg/kg/day). Among the tested aminoglycosides, gentamicin showed the best efficacy, with the best results after 24 h of treatment for the highest dosage.

Calculation of the transition from pairing vibrational to pairing rotational regimes between magic nuclei ¹°°Sn and ¹³²Sn via two-nucleon transfer reactions.

Absolute values of two-particle transfer cross sections along the Sn-isotopic chain are calculated. They agree with measurements within errors and without free parameters. Within this scenario, the predictions concerning the absolute value of the two-particle transfer cross sections associated with the excitation of the pairing vibrational spectrum expected around the recently discovered closed shell nucleus(50)(132)Sn(82) and the very exotic nucleus (50)(100)Sn(50) can be considered quantitative, opening new perspectives in the study of pairing in nuclei.

A new experimental model of acute osteomyelitis due to methicillin-resistant Staphylococcus aureus in rabbit.

AIMS: To assess the impact of antibiotic therapy on severe osseous infections, animal models of chronic bacterial infections have been developed; however, these models suffer from many experimental limitations. The aim of this work was to develop a new model system in which high levels of bacteria are obtained within femoral bone marrow and bone tissue, and such infections are maintained for at least 14 days. METHODS AND RESULTS: Experimental osteomyelitis was induced in 25 New Zealand white rabbits. A 10(9) CFU ml(-1) suspension of methicillin-resistant Staphylococcus aureus was injected into the knee after bone trepanation. On day 3, surgical debridement was performed to mimic a surgical procedure. Animals were euthanized 1, 2, 3, 9 and 14 days post-inoculation to determine the bacterial counts in marrow and bone, and to evaluate the stability of the infection. Inoculated lesions also were assessed for changes in histological parameters on days 3 and 7 post-inoculation. At days 1, 2, 3, 9 and 14 post-inoculation, we observed 6·50 ± 0·64, 7·30 ± 0·49, 7·82 ± 0·19, 8·00 ± 1·48 and 8·99 ± 0·20 log10 CFU g(-1) in bone marrow and 8·40 ± 0·68, 7·65 ± 0·27, 7·58 ± 0·30, 8·88 ± 0·52 and 8·28 ± 0·39 log10 CFU g(-1) in bone tissue, respectively. No statistical differences in bacterial count were found between bone marrow and bone tissue at any time point. CONCLUSION: This new model of acute osteomyelitis was validated by histological and microbiological changes in the absence of sclerosing agents, and these changes remained stable for 14 days. SIGNIFICANCE AND IMPACT OF THE STUDY: These results describe a new experimental model of acute osteomyelitis and demonstrate its usefulness in assessing the activity of antibacterial agents in vivo soon after bone infection.

In vivo assessment of the antimicrobial activity of a calcium-deficient apatite vancomycin drug delivery system in a methicillin-resistant Staphylococcus aureus rabbit osteomyelitis experimental model.

The antimicrobial activities of calcium-deficient apatite loaded with different concentrations (25, 100, and 500 microg/mg) of vancomycin as a filling biomaterial were evaluated in a methicillin-resistant Staphylococcus aureus (MRSA) rabbit acute osteomyelitis model. Bacterial counts in bone, bone marrow, and joint fluid samples treated with forms of the apatite were compared to those in tissue samples receiving a constant intravenous vancomycin infusion after 4 days. This study demonstrates that using a calcium-deficient apatite loaded with vancomycin dramatically decreases the bacterial counts in bone and marrow.