Excited-State Half-Lives in

The known I^{π}=8_{1}^{+}, E_{x}=2129-keV isomer in the semimagic nucleus ^{130}Cd_{82} was populated in the projectile fission of a ^{238}U beam at the Radioactive Isotope Beam Factory at RIKEN. The high counting statistics of the accumulated data allowed us to determine the excitation energy, E_{x}=2001.2(7) keV, and half-life, T_{1/2}=57(3) ns, of the I^{π}=6_{1}^{+} state based on γγ coincidence information. Furthermore, the half-life of the 8_{1}^{+} state, T_{1/2}=224(4) ns, was remeasured with high precision. The new experimental information, combined with available data for ^{134}Sn and large-scale shell model calculations, allowed us to extract proton and neutron effective charges for ^{132}Sn, a doubly magic nucleus far-off stability. A comparison to analogous information for ^{100}Sn provides first reliable information regarding the isospin dependence of the isoscalar and isovector effective charges in heavy nuclei.

Improved Value for the Gamow-Teller Strength of the

A record number of ^{100}Sn nuclei was detected and new isotopic species toward the proton dripline were discovered at the RIKEN Nishina Center. Decay spectroscopy was performed with the high-efficiency detector arrays WAS3ABi and EURICA. Both the half-life and the ß-decay end point energy of ^{100}Sn were measured more precisely than the literature values. The value and the uncertainty of the resulting strength for the pure 0^{+}→1^{+} Gamow-Teller decay was improved to B_{GT}=4.4_{-0.7}^{+0.9}. A discrimination between different model calculations was possible for the first time, and the level scheme of ^{100}In is investigated further.

Proton Shell Evolution below

The ß-delayed γ-ray spectroscopy of neutron-rich ^{123,125}Ag isotopes is investigated at the Radioactive Isotope Beam Factory of RIKEN, and the long-predicted 1/2^{-} ß-emitting isomers in ^{123,125}Ag are identified for the first time. With the new experimental results, the systematic trend of energy spacing between the lowest 9/2^{+} and 1/2^{-} levels is extended in Ag isotopes up to N=78, providing a clear signal for the reduction of the Z=40 subshell gap in Ag towards N=82. Shell-model calculations with the state-of-the-art V_{MU} plus M3Y spin-orbit interaction give a satisfactory description of the low-lying states in ^{123,125}Ag. The tensor force is found to play a crucial role in the evolution of the size of the Z=40 subshell gap. The observed inversion of the single-particle levels around ^{123}Ag can be well interpreted in terms of the monopole shift of the π1g_{9/2} orbitals mainly caused by the increasing occupation of ν1h_{11/2} orbitals.

Pulsatile Hematuria From Procurement Core Needle Biopsy: A Case Report.

Core needle biopsies are still widely performed to evaluate the pathologic suitability of a kidney allograft. Here, we report a case of pulsatile hematuria from a procurement core needle biopsy where the patient had to be taken emergently to interventional radiology for coil embolization immediately after organ reperfusion.

Hospital Readmissions After Intestinal and Multivisceral Transplantation.

BACKGROUND: Intestinal transplant recipients require frequent hospital readmission after a successful transplantation, but the reasons for readmission have not been characterized in detail. METHODS: We reviewed our single-center experience to characterize the patterns of readmissions and to identify preventable causes. Among 87 adult patients who received an intestinal or multivisceral transplant, 65 patients (35 males, 30 females; median age, 42 years [range, 19-66]) with a follow-up of at least 1 year were included in this study. Readmissions were defined as any unplanned inpatient hospital stay of 24 hours or longer occurring within 1 year after discharge from the transplantation admission and were classified as early (<1 month) and late (months 2-12) readmissions. RESULTS: Forty-four (68%) patients required early, and 59 (91%) patients required late readmission. A total of 333 readmissions (median, 4 readmissions/patient [0-20]) occurred within the first year post-transplantation; 69 were early (21%) and 264 were late (79%), resulting in a total of 4089 days of hospital stay (median, 7 days/readmission [2-136]). The three most frequent causes of readmission were dehydration, infection, and surgical complications. CONCLUSIONS: These findings suggest that the rate of hospital readmission after intestinal transplantation could potentially be reduced by optimizing fluid balance and hydration status after discharge.

New Isotopes and Proton Emitters-Crossing the Drip Line in the Vicinity of

Several new isotopes, ^{96}In, ^{94}Cd, ^{92}Ag, and ^{90}Pd, have been identified at the RIKEN Nishina Center. The study of proton drip-line nuclei in the vicinity of ^{100}Sn led to the discovery of new proton emitters ^{93}Ag and ^{89}Rh with half-lives in the submicrosecond range. The systematics of the half-lives of odd-Z nuclei with T_{z}=-1/2 toward ^{99}Sn shows a stabilizing effect of the Z=50 shell closure. Production cross sections for nuclei in the vicinity of ^{100}Sn measured at different energies and target thicknesses were compared to the cross sections calculated by epax taking into account contributions of secondary reactions in the primary target.

Increased efficacy of inactivated vaccine candidates prepared with Salmonella enterica serovar Typhimurium strains of predominant genotypes in ducks.

Salmonella enterica serovar Typhimurium has been a major causative agent of food-borne human disease, mainly due to consumption of contaminated food animal products. In particular, ducks serve as a reservoir of serovar Typhimurium, and are one of the common sources of human infection. To prevent infection of ducks, and therefore minimize human infection, it is critical to control the persistent epidemic strains in ducks. Here, we analyzed the genetic diversity and virulence of serovar Typhimurium isolates from ducks in Korea to identify the predominant strains that might be used as efficient vaccine candidates for ducks. Among the isolates, 2 representative isolates (ST26 and ST76) of predominant genotypes were selected as vaccine strains on the basis of genotypic analysis by pulsed-field gel electrophoresis and DNA microarrays. Two-week-old ducks were then injected intramuscularly with inactivated vaccine candidates prepared using ST26 or ST76 (10(8) cfu/0.5 mL/duck or 10(9) cfu/0.5 mL/duck), and oral challenge with a highly virulent serovar Typhimurium strain (10(9) cfu/0.5 mL/duck) was carried out 2 wk later. Shedding of the challenge strain was significantly decreased in group 2 after vaccination. The antibody levels by enzyme-linked immunosorbent assay in all vaccinated groups were enhanced significantly (P < 0.05) compared to the unvaccinated control group. Overall, vaccination with ST26 or ST76 reduced bacterial shedding and colonization in internal organs, and induced elevated antibody response. In particular, serovar Typhimurium ST26 (10(8) cfu/0.5 mL/duck) was the most effective vaccine candidate, which can provide efficient protection against serovar Typhimurium in ducks with higher effectiveness compared to a commercial vaccine currently used worldwide.

ß-Decay Half-Lives of 110 Neutron-Rich Nuclei across the N=82 Shell Gap: Implications for the Mechanism and Universality of the Astrophysical r Process.

The ß-decay half-lives of 110 neutron-rich isotopes of the elements from _{37}Rb to _{50}Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A≈130) and the rare-earth-element (A≈160) abundance peaks may result from the freeze-out of an (n,γ)⇄(γ,n) equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r-process events.

Yrast 6⁺ seniority isomers of (136,138)Sn.

Delayed γ-ray cascades, originating from the decay of (6⁺) isomeric states, in the very neutron-rich, semimagic isotopes (136,138)Sn have been observed following the projectile fission of a ²³8U beam at RIBF, RIKEN. The wave functions of these isomeric states are proposed to be predominantly a fully aligned pair of f(7/2) neutrons. Shell-model calculations, performed using a realistic effective interaction, reproduce well the energies of the excited states of these nuclei and the measured transition rates, with the exception of the B(E2;6⁺→4⁺) rate of ¹³6Sn, which deviates from a simple seniority scheme. Empirically reducing the νf(7/2)(2) orbit matrix elements produces a 41⁺ state with almost equal seniority 2 and 4 components, correctly reproducing the experimental B(E2;6⁺→4⁺) rate of ¹³6Sn. These data provide a key benchmark for shell-model interactions far from stability.

Monopole-driven shell evolution below the doubly magic nucleus 132Sn explored with the long-lived isomer in 126Pd.

A new isomer with a half-life of 23.0(8) ms has been identified at 2406 keV in (126)Pd and is proposed to have a spin and parity of 10(+) with a maximally aligned configuration comprising two neutron holes in the 1h(11/2) orbit. In addition to an internal-decay branch through a hindered electric octupole transition, ß decay from the long-lived isomer was observed to populate excited states at high spins in (126)Ag. The smaller energy difference between the 10(+) and 7(-) isomers in (126)Pd than in the heavier N=80 isotones can be interpreted as being ascribed to the monopole shift of the 1h(11/2) neutron orbit. The effects of the monopole interaction on the evolution of single-neutron energies below (132)Sn are discussed in terms of the central and tensor forces.

1p3/2 proton-hole state in 132Sn and the shell structure along N = 82.

A low-lying state in 131In82, the one-proton hole nucleus with respect to double magic 132Sn, was observed by its γ decay to the Iπ=1/2- ß-emitting isomer. We identify the new state at an excitation energy of Ex=1353 keV, which was populated both in the ß decay of 131Cd83 and after ß-delayed neutron emission from 132Cd84, as the previously unknown πp3/2 single-hole state with respect to the 132Sn core. Exploiting this crucial new experimental information, shell-model calculations were performed to study the structure of experimentally inaccessible N=82 isotones below 132Sn. The results evidence a surprising absence of proton subshell closures along the chain of N=82 isotones. The consequences of this finding for the evolution of the N=82 shell gap along the r-process path are discussed.

Phenotypic traits, virulence-associated gene profile and genetic relatedness of Edwardsiella tarda isolates from Japanese eel Anguilla japonica in Korea.

UNLABELLED: Edwardsiella tarda is the predominant bacterium in farm-cultured eel in Korea. Here, we evaluated the heterogeneity of 37 E. tarda isolates derived from Japanese eel with various origins (olive flounder, common carp and ornamental fish) between 2003 and 2010. Regardless of origins, the biochemical characteristics of E. tarda isolates were homogenous except hydrogen sulfide production, citrate utilization and mannitol fermentation. Based on the phylogenetic analysis of 16S rRNA, E. tarda isolates could be classified into two subgroups and displayed a close relation with Edwardsiella ictaluri and Edwardsiella hosinae lineages, suggesting that the subgroup I has been a predominant type in the Jeonnam and Jeonbuk provinces. I-CeuI-based pulsed-field gel electrophoresis (PFGE) typing showed that the isolates from Japanese eels belonged to 11 pulsotypes, indicating that the presence of highly genomic diversity. Additionally, two isolates, ET-060 and ET-191, showed a high frequency of virulence genes (100%) and caused 90% and 60% mortality in Japanese eel, respectively. This finding suggests a substantial congruence of virulence gene profiles and pathogenicity. Our results demonstrate that the intraspecific diversity within E. tarda strains from Japanese eel has been in prior existence. SIGNIFICANCE AND IMPACT OF THE STUDY: Based on the biochemical characteristics, the phylogenetic property of the 16S rRNA gene and PFGE types of Edwardsiella tarda, we could identify the intraspecific diversity of isolates from Japanese eel, Anguilla japonica in Korea. In addition, this study describes the strong congruence of virulence-related genes and pathogenicity, suggesting that the virulence profile may be useful tool for prediction of pathogenicity.

Isomers in 128Pd and 126Pd: evidence for a robust shell closure at the neutron magic number 82 in exotic palladium isotopes.

The level structures of the very neutron-rich nuclei 128Pd and 126Pd have been investigated for the first time. In the r-process waiting-point nucleus 128Pd, a new isomer with a half-life of 5.8(8) µs is proposed to have a spin and parity of 8(+) and is associated with a maximally aligned configuration arising from the g(9/2) proton subshell with seniority υ=2. For 126Pd, two new isomers have been identified with half-lives of 0.33(4) and 0.44(3) µs. The yrast 2(+) energy is much higher in 128Pd than in 126Pd, while the level sequence below the 8(+) isomer in 128Pd is similar to that in the N=82 isotone 130Cd. The electric quadrupole transition that depopulates the 8(+) isomer in 128Pd is more hindered than the corresponding transition in 130Cd, as expected in the seniority scheme for a semimagic, spherical nucleus. These experimental findings indicate that the shell closure at the neutron number N=82 is fairly robust in the neutron-rich Pd isotopes.

Prevalence and characteristics of intimin-producing Escherichia coli strains isolated from healthy chickens in Korea.

Virulent Escherichia coli strains have commonly been associated with diarrheal illness in humans and animals. Typical enteropathogenic Escherichia coli (EPEC) with intimin gene (eaeA) and E. coli adherence factor plasmid, or atypical EPEC with only eaeA have been implicated in human cases. In the present study, we investigated the prevalence of virulence-associated genes including eaeA in the E. coli strains isolated from cloacal specimens of 184 chicken flocks in 7 provinces in Korea between 2009 and 2010. When 7 virulence genes (VT1, VT2, LT, and ST for enterotoxigenic E. coli; eaeA and bfpA for enteropathogenic E. coli; and aggR for enteroaggregative E. coli) were screened by multiplex PCR, a total of 30 E. coli strains carrying only the eaeA gene were detected from 184 flocks that were identified as atypical enteropathogenic Escherichia coli (aEPEC). The aEPEC strains were analyzed by eae subtyping, phylogenetic grouping PCR, and serotyping. Twelve (40%) of 30 aEPEC strains possessed an eae-ß subtype, followed by θ (30%), ε (16.7%), and ß1 (13.3%). Eight (26.7%) of 30 aEPEC strains were designated into the phylogenetic group A. Two (6.7%) and 3 (10%) aEPEC strains were classified into the phylogenetic group B2 and D, respectively. A total of 15 (50%) aEPEC strains were serotyped to groups O24, O25, O26, O71, O80, O103, and O157, and the remaining strains were nontypeable. In analyzing the genetic diversity among the 30 aEPEC isolates by the pulsed-field gel electrophoresis method with XbaI-digestion, the pulsed-field gel electrophoresis profiling produced 20 different patterns, but isolates within the same group did not show clear geographic or breed relationships. Our data indicate that healthy chickens may constitute an important natural reservoir of aEPEC strains, and suggest that transmission to humans could not be excluded.

Outbreak of gizzard erosion associated with fowl adenovirus infection in Korea.

The pathogenicity of a fowl adenovirus serotype-1 (FAdV-1, K181 strain) isolated from a case of gizzard erosion in layer chickens was investigated in specific-pathogen-free (SPF) chicks. One-week-old SPF chicks were inoculated orally or intramuscularly with the isolate of FAdV-1 and euthanized for necropsy at 7, 14, and 21 d postinoculation. Although there were no clinical signs after inoculation, gizzard erosions were observed grossly and the virus was recovered from the gizzards in the inoculated chickens. Histologically, in the chickens that were infected orally, the lesions found in the gizzard consisted of severe degeneration and necrosis of glandular epitheliums and eosinophilic inclusion bodies. These results indicate that the Korean FAdV-1 isolate could induce gizzard lesions in chickens. Moreover, the present investigation reproduced an outbreak of gizzard erosion caused by FAdV-1 infection and, for the first time, described the isolation of FAdV-1 from chickens in Korea. These findings provide important information on the epidemiology and pathogenesis of FAdV-1 infection in chickens.

The embryo lethality of Escherichia coli isolates and its relationship to the presence of virulence-associated genes.

The aims of this study were to determine if the chicken embryo lethality assay and the presence of 9 virulence-associated genes of Escherichia coli were correlated and to discover which virulence genes contributed most to embryo lethality. We examined 58 E. coli strains isolated from visceral organs of chickens with colibacillosis for the presence of 9 virulence genes (fimC, tsh, fyuA, irp2, iucD, cvi/cva, iss, astA, and vat) by PCR. The gene FimC (type I fimbriae) was detected with the highest prevalence in 93.1% of the isolates, followed by iucD (67.24%), iss (58.62%), tsh (34.48%), cvi/cva (34.48%), fyuA (32.76%), astA (31.0%), irp2 (27.59%), and vat (17.24%). The embryo mortality ranged from 5 to 100%; however, most of the isolates were moderately or highly virulent. High positive correlations were observed between the presence of virulence genes and chicken embryo lethality. In addition, presence of the iucD (aerobactin) gene was the trait that best contributed to embryo mortality by using the multivariate model. These results suggest that expression frequency of these 9 virulence genes is associated with embryo mortality, and the gene that best predicted embryo mortality was iucD.

Abnormal CX3CR1⁺ lamina propria myeloid cells from intestinal transplant recipients with NOD2 mutations.

Although progress has been made in intestinal transplantation, chronic inflammation remains a challenge. We have reported that the risk of immunological graft loss is almost 100-fold greater in recipients who carry any of the prevalent NOD2 polymorphisms associated with Crohn's disease, and have shown that the normal levels of a key antimicrobial peptide produced by the Paneth cells of the allograft, fall as the graft becomes repopulated by hematopoietic cells of the NOD2 mutant recipient. These studies are extended in this report. Within several months following engraftment into a NOD2 mutant recipient the allograft loses its capacity to prevent adherence of lumenal microbes. Despite the significantly increased expression of CX3CL1, a stress protein produced by the injured enterocyte, NOD2 mutant CX3CR1(+) myeloid cells within the lamina propria fail to exhibit the characteristic morphological phenotype, and fail to express key genes required expressed by NOD2 wild-type cells, including Wnt 5a. We propose that the CX3CR1(+) myeloid cell within the lamina propria supports normal Paneth cell function through expression of Wnt 5a, and that this function is impaired in the setting of intestinal transplantation into a NOD2 mutant recipient. The therapeutic value of Wnt 5a administration in this setting is proposed.

Characterization of Escherichia coli isolates from laying hens with colibacillosis on 2 commercial egg-producing farms in Korea.

The present study reports on layer chickens with colibacillosis in 2 commercial egg-producing farms (referred to as farm A and farm B, which were managed by the same owner and were about 1 km apart) in the middle region of the Korean peninsula. The 2 flocks were infected at the initiation of egg laying. They were characterized by no previous clinical signs but sudden mortality (2.7-4.0%), with severe lesions of septicemia and fibrinous polyserositis. Escherichia coli was isolated from the lesions of the infected birds. Serotyping tests identified isolates that belonged to somatic groups O1 (12/17), O46 (2/17), O78 (1/17), and O84 (1/17) or that were unidentified (1/17). Thirteen of 17 E. coli isolates (76.4%) obtained from 11 birds in the 2 flocks showed similar pulsed-field gel electrophoresis patterns that were arbitrarily designated as pattern A. The isolates had high frequencies of putative virulence genes including 100% [fimC (type 1 fimbriae), iucD (aerobactin synthesis), and iss (increased serum survival)], 94.1% [cva/cvi (structural genes of colicin V operon) and vat (vacuolating autotransporter toxin)], 88.2% [irp2, iron-repressible protein (yersinia bactin) synthesis, and fyuA, ferric yersinia uptake], and 82.3% [tsh (temperature-sensitive hemagglutinin)]; astA (encoding a heat-stable cytotoxin associated with enteroaggregative E. coli) was not associated with the enteric disorder. These data suggest that all chickens with colibacillosis on farms A and B were likely infected by E. coli strains that are highly pathogenic in avian species.

Molecular characterization of chicken infectious anemia viruses detected from breeder and broiler chickens in South Korea.

In South Korea, 32 sequences of chicken infectious anemia virus (CIAV) from various flocks of breeder and commercial chickens were genetically characterized for the first time. Phylogenetic analysis of the viral protein 1 gene, including a hypervariable region of the CIAV genome, indicated that Korean CIAV strains were separated into groups II, IIIa, and IIIb. Strains were commonly identified in great-grandparent and grandparent breeder farms as well as commercial chicken farms. In the field, CIAV strains from breeder farms had no clinical effects, but commercial farm strains were associated with depression, growth retardation, and anemia regardless of the group from which the strain originated. In addition, we identified 7 CIAV genomes that were similar to vaccine strains from vaccinated and unvaccinated breeder flocks. These data suggest that further studies on pathogenicity and vaccine efficacy against the different CIAV group are needed, along with continuous CIAV surveillance and genetic analysis at breeder farms.

Occurrence of purulent arthritis broilers vertically infected with Salmonella enterica serovar Enteritidis in Korea.

Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) has been associated with morbidity and mortality in broiler chickens worldwide. The present study described purulent arthritis of broilers infected with Salmonella Enteritidis and investigated antibiograms and genetic characteristics of Salmonella Enteritidis isolates from epidemiologically related properties such as a hatchery and breeder farm in an attempt to elucidate the source of contamination. Clinical disease and mortality were observed in the affected broiler flock. Mortality was 5.8% until 12 d of age. The birds typically showed lameness with moderately swollen hock joints and footpads. The most prevalent lesions were severely purulent arthritis with polyserositis. Histopathology revealed moderate to severe inflammation in the synovial membrane of leg joints and visceral organs. When the antimicrobial susceptibility test was performed against 7 isolates of Salmonella Enteritidis from broilers, and relevant hatchery and breeder farms by the disk diffusion method using 18 antimicrobial agents, isolates from broiler and breeder farms had the same antibiogram characterized by multiple drug resistance to ampicillin, ceftiofur, cephalothin, gentamycin, nalidixic acid, streptomycin, sulfisoxazole, and tetracycline, whereas isolates from the hatchery were differently resistant to only nalidixic acid. Through the genetic analysis with pulsed-field gel electrophoresis using the restriction enzyme XbaI, Salmonella Enteritidis isolates from both broiler and breeder farms also showed the same PFGE pattern compared with the hatchery isolates resistant to nalidixic acid. As a result, the same PFGE profiles and antibiogram patterns among isolates from broilers and breeder farms provided direct evidence of vertical Salmonella Enteritidis transmission from the contaminated breeder farm to commercial broiler.