1,054 research outputs found
Possible Deuteron-like Molecular States Composed of Heavy Baryons
We perform a systematic study of the possible loosely bound states composed
of two charmed baryons or a charmed baryon and an anti-charmed baryon within
the framework of the one boson exchange (OBE) model. We consider not only the
exchange but also the , , , and
exchanges. The mixing effects for the spin-triplets are also taken into
account. With the derived effective potentials, we calculate the binding
energies and root-mean-square (RMS) radii for the systems
, ,
,
and
. Our numerical results indicate that: (1)
the H-dibaryon-like state does not exist; (2) there may
exist four loosely bound deuteron-like states and
with small binding energies and large RMS radii.Comment: 17 pages, 32 figure
Earthquake-related pelvic crush fracture vs. non-earthquake fracture on digital radiography and MDCT: a comparative study
OBJECTIVE: To determine the features of earthquake-related pelvic crush fractures versus non-earthquake fractures with digital radiography and multidetector row computed tomography. METHODS: One hundred and sixty-seven survivors with pelvic crush fractures in the 2008 Sichuan earthquake were entered in our study as the earthquake-related group (139 underwent digital radiography, 28 underwent multidetector row computed tomography); 70 victims with non-earthquake pelvic fractures were enrolled into this study as the non-earthquake group (54 underwent digital radiography, 16 underwent multidetector row computed tomography). Data were reviewed retrospectively between groups, focusing on anatomic distributions, status of pelvic bone fractures, numbers of pelvic bones involved, and classification of pelvic ring fractures according to the Tile classification system. RESULTS: Pelvic fractures occurred more frequently in the pubis in the earthquake-related group than in the non-earthquake group (135/167, 81% vs. 48/70, 69%). In addition, comminuted fractures were more common in the earthquake-related group than in the non-earthquake group (55/167, 33% vs. 10/70, 14%). Multiple fractures were less common in the earthquake-related group than in the non-earthquake group (81/167, 49% vs. 46/70, 66%). Regarding the classification of pelvic ring fractures, Type C predominantly composed of subtype C3 occurred more frequently (64/167, 38% vs. 12/70, 17%), and Type A was less common in the earthquake-related group than in the non-earthquake group (31/167, 19% vs. 23/70, 32%). All differences were statistically significant (
Phylogenomic reconstruction of lactic acid bacteria: an update
<p>Abstract</p> <p>Background</p> <p>Lactic acid bacteria (LAB) are important in the food industry for the production of fermented food products and in human health as commensals in the gut. However, the phylogenetic relationships among LAB species remain under intensive debate owing to disagreements among different data sets.</p> <p>Results</p> <p>We performed a phylogenetic analysis of LAB species based on 232 genes from 28 LAB genome sequences. Regardless of the tree-building methods used, combined analyses yielded an identical, well-resolved tree topology with strong supports for all nodes. The LAB species examined were divided into two groups. Group 1 included families Enterococcaceae and Streptococcaceae. Group 2 included families Lactobacillaceae and Leuconostocaceae. Within Group 2, the LAB species were divided into two clades. One clade comprised of the acidophilus complex of genus <it>Lactobacillus </it>and two other species, <it>Lb. sakei </it>and <it>Lb. casei</it>. In the acidophilus complex, <it>Lb. delbrueckii </it>separated first, while <it>Lb. acidophilus</it>/<it>Lb. helveticus </it>and <it>Lb. gasseri</it>/<it>Lb. johnsonii </it>were clustered into a sister group. The other clade within Group 2 consisted of the salivarius subgroup, including five species, <it>Lb. salivarius</it>, <it>Lb. plantarum</it>, <it>Lb. brevis</it>, <it>Lb. reuteri</it>, <it>Lb. fermentum</it>, and the genera <it>Pediococcus, Oenococcus</it>, and <it>Leuconostoc</it>. In this clade, <it>Lb. salivarius </it>was positioned most basally, followed by two clusters, one corresponding to <it>Lb. plantarum</it>/<it>Lb. brevis </it>pair and <it>Pediococcus</it>, and the other including <it>Oenococcus</it>/<it>Leuconostoc </it>pair and <it>Lb. reuteri</it>/<it>Lb. fermentum </it>pair. In addition, phylogenetic utility of the 232 genes was analyzed to identify those that may be more useful than others. The genes identified as useful were related to translation and ribosomal structure and biogenesis (TRSB), and a three-gene set comprising genes encoding ultra-violet resistance protein B (<it>uvrB</it>), DNA polymerase III (<it>polC</it>) and penicillin binding protein 2B (<it>pbpB</it>).</p> <p>Conclusions</p> <p>Our phylogenomic analyses provide important insights into the evolution and diversification of LAB species, and also revealed the phylogenetic utility of several genes. We infer that the occurrence of multiple, independent adaptation events in LAB species, have resulted in their occupation of various habitats. Further analyses of more genes from additional, representative LAB species are needed to reveal the molecular mechanisms underlying adaptation of LAB species to various environmental niches.</p
Earthquake-related pelvic crush fracture vs. non-earthquake fracture on digital radiography and MDCT: a comparative study
OBJECTIVE: To determine the features of earthquake-related pelvic crush fractures versus non-earthquake fractures with digital radiography and multidetector row computed tomography. METHODS: One hundred and sixty-seven survivors with pelvic crush fractures in the 2008 Sichuan earthquake were entered in our study as the earthquake-related group (139 underwent digital radiography, 28 underwent multidetector row computed tomography); 70 victims with non-earthquake pelvic fractures were enrolled into this study as the non-earthquake group (54 underwent digital radiography, 16 underwent multidetector row computed tomography). Data were reviewed retrospectively between groups, focusing on anatomic distributions, status of pelvic bone fractures, numbers of pelvic bones involved, and classification of pelvic ring fractures according to the Tile classification system. RESULTS: Pelvic fractures occurred more frequently in the pubis in the earthquake-related group than in the non-earthquake group (135/167, 81% vs. 48/70, 69%). In addition, comminuted fractures were more common in the earthquake-related group than in the non-earthquake group (55/167, 33% vs. 10/70, 14%). Multiple fractures were less common in the earthquake-related group than in the non-earthquake group (81/167, 49% vs. 46/70, 66%). Regarding the classification of pelvic ring fractures, Type C predominantly composed of subtype C3 occurred more frequently (64/167, 38% vs. 12/70, 17%), and Type A was less common in the earthquake-related group than in the non-earthquake group (31/167, 19% vs. 23/70, 32%). All differences were statistically significant (p<0.05). No difference was found in Type B fractures between the groups (72/167, 43% vs. 35/70, 50%). CONCLUSION: Earthquake-related pelvic crush fractures can be characterized by a high incidence of pelvic fractures occurring in the pubis, comminuted fractures, and Type C fractures predominantly composed by subtype C3, despite a low incidence of multiple fractures
Novel charmonium-like structures in the and invariant mass spectra
Stimulated by the new evidence of Y(4274) observed in the
invariant mass spectrum, we first propose the charmonium-like state Y(4274) as
the S-wave molecular state with , which
is supported well by dynamics study of the system composed of the pseudoscalar
and scalar charmed mesons. The S-wave molecular
charmonium appears as the molecular partner of Y(4274), which is in accord with
the enhancement structure appearing at 4.2 GeV in the invariant
mass spectrum from B decays. Our study shows that the enhancement structures,
, the newly observed Y(4274) and the previously announced
in the and invariant mass
spectra, can be understood well under the uniform framework of the molecular
charmonium, which can be tested by future experiments.Comment: 4 pages, 4 figures. Accepted for publication by Phys. Lett.
On a New Criterion for Meromorphic Starlike Functions
The main purpose of this paper is to derive a new criterion for meromorphic starlike functions of order α
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