7,974 research outputs found
A Study of Final State Effects in the electrodisintegration of a polarized Helium-3 target
An approach for the description of the final state interaction in the
evaluation of inclusive electromagnetic responses of a polarized Helium-3
target, is briefly illustrated. Preliminary results of calculations, where the
final state interaction is fully taken into account for the two-body break-up
channel, are compared with experimental data, showing a very encouraging
improvement with respect to the plane wave impulse approximation results.Comment: 8 pages. Proc. of "GDH 2004", Old Dominion University, Norfolk, Va,
June 2-5, 2004. Class file "ws-procs9x6.cls" and style file "rotating_pr.sty"
include
Neutron electromagnetic form factors and inclusive scattering of polarized electrons by polarized He and H targets
The electromagnetic inclusive responses of polarized He and H are
thoroughly investigated at the quasielastic peak for squared momentum transfers
up to , within the plane wave impulse approximation. Great
emphasys is put on the effects in the bound-state due to different two- and
three-body nuclear forces, and to the Coulomb interaction as well. A careful
analysis of the polarized responses allows to select possible experiments for
minimizing the model dependence in the extraction of the neutron
electromagnetic form factors. In particular, the relevant role played by the
proton in the transverse-longitudinal response of polarized He, at low
momentum transfer, can be utilized for obtaining valuable information on the
proton contribution to the total polarized response and eventually on the
neutron charge form factor.Comment: 27 pages, Latex, 9 Postscript figures. To appear in Phys. Rev. C
(July '97
Scedosporium prolificans Septic Arthritis
Scedosporium prolificans is an emerging fungal pathogen that can cause significant morbidity, and even mortality, in both immunocompromised and immunocompetent patients. Approximately 10% of patients affected by this rare fungal pathogen present with septic osteomyelitis or arthritis. Overall, the rate of mortality is close to 50%, and several patients with orthopedic infections have required amputations.1 Our patient is a 59-year-old woman, with a history of rheumatoid arthritis requiring immunosuppressants, who presented with a 5-month history of right wrist pain and swelling. She described an oscillating course of swelling, erythema, and pain involving the dorsal aspect of her wrist that did not show sustained response to antibiotics or a radiocarpal joint steroid injection given by other providers. On initial examination, she was afebrile with dorsal wrist swelling. There was no erythema, but wrist mobility was limited. She had tenderness throughout the wrist, but no fluctuance or drainage. All initial laboratory work was normal. Right wrist X-ray showed severe osteopenia with some mild evidence of cortical erosion. Despite the normal laboratory values, her presenting findings of swelling, radiographic erosions, and immunocompromised state prompted concern for atypical septic arthritis. The patient subsequently underwent wrist exploration for tissue and culture harvest. In addition to extensive wrist synovectomy, the proximal pole of the scaphoid, lunate, triquetrum, capitate, hamate, and metacarpal bases all showed evidence of necrosis that required debridement. One week later, her fluid aspirate and bone cultures unexpectedly grew an unidentified fungal species, and she was taken back to the operating room for further debridement and placement of a voriconazole-impregnated cement spacer. The culture grew pan-resistant Scedosporium prolificans, and based on recommendations from Rheumatology and Infectious Disease, the patient was started on a 6-week course of intravenous micafungin, and immunosuppressive medications were stopped. She returned to the operating room for debridement and serial treatments with polyhexamethylene biguanide (PHMB) irrigation until intraoperative tissue cultures showed no growth. PHMB is an antiseptic medication that has been described as a local adjunct to the treatment of resistant fungal infections.2–4 After successful eradication of her infection, she underwent wrist reconstruction and fusion with a double-barrel free fibula osteocutaneous flap. She is now 18 months out from her reconstruction, has healed uneventfully, and has a functional, painless upper extremity
Systematic and biological studies of the leopard frogs (Rana pipiens complex) of the United States.
http://deepblue.lib.umich.edu/bitstream/2027.42/56392/1/MP148.pd
Evidence of a new low field cross-over in the vortex critical velocity of type-II superconducting thin films
We measure current-voltage characteristics as function of magnetic field and
temperature in Nb strips of different thickness and width. The instability
voltage of the flux flow state related to the vortex critical velocity v* is
studied and compared with the Larkin-Ovchinnikov theory. Beside the usual
power-law dependence v* ~ B^-1/2, in the low field range a new cross-over
field, Bcr1, is observed below which v* decreases by further lowering the
external magnetic field B. We ascribe this unexpected cross-over to vortex
channeling due to a fan-like penetration of the applied magnetic field as
confirmed by magneto-optic imaging. The observation of Bcr1 becomes a direct
evidence of a general feature in type-II superconducting films at low fields,
that is a channel-like vortex motion induced by the inhomogeneous magnetic
state caused by the relatively strong pinning
Highlights of Recent Results with Clas
Recent results on the study of the electromagnetic structure of nucleon
resonances, the spin structure of proton and neutrons at small and intermediate
photon virtualities, and the search for exotic pentaquark baryons are
presented.Comment: 12 pages, 8 figures, invited talk at MENU2004, Beijin
The Most Severe Test for Hydrophobicity Scales: Two Proteins with 88% Sequence Identity but Different Structure and Function
Protein-protein interactions (protein functionalities) are mediated by water,
which compacts individual proteins and promotes close and temporarily stable
large-area protein-protein interfaces. In their classic paper Kyte and
Doolittle (KD) concluded that the "simplicity and graphic nature of
hydrophobicity scales make them very useful tools for the evaluation of protein
structures". In practice, however, attempts to develop hydrophobicity scales
(for example, compatible with classical force fields (CFF) in calculating the
energetics of protein folding) have encountered many difficulties. Here we
suggest an entirely different approach, based on the idea that proteins are
self-organized networks, subject to finite-scale criticality (like some network
glasses). We test this proposal against two small proteins that are delicately
balanced between alpha and alpha/beta structures, with different functions
encoded with only 12% of their amino acids. This example explains why protein
structure prediction is so challenging, and it provides a severe test for the
accuracy and content of hydrophobicity scales. The new method confirms KD's
evaluation, and at the same time suggests that protein structure, dynamics and
function can be best discussed without using CFF
Beta defensin-2 is reduced in central but not in distal airways of smoker COPD patients
Background: Altered pulmonary defenses in chronic obstructive pulmonary disease (COPD) may promote distal airways bacterial colonization. The expression/activation of Toll Like receptors (TLR) and beta 2 defensin (HBD2) release by epithelial cells crucially affect pulmonary defence mechanisms. Methods: The epithelial expression of TLR4 and of HBD2 was assessed in surgical specimens from current smokers COPD (s-COPD; n = 17), ex-smokers COPD (ex-s-COPD; n = 8), smokers without COPD (S; n = 12), and from non-smoker non-COPD subjects (C; n = 13). Results: In distal airways, s-COPD highly expressed TLR4 and HBD2. In central airways, S and s-COPD showed increased TLR4 expression. Lower HBD2 expression was observed in central airways of s-COPD when compared to S and to ex-s-COPD. s-COPD had a reduced HBD2 gene expression as demonstrated by real-time PCR on micro-dissected bronchial epithelial cells. Furthermore, HBD2 expression positively correlated with FEV1/FVC ratio and inversely correlated with the cigarette smoke exposure. In a bronchial epithelial cell line (16 HBE) IL-1β significantly induced the HBD2 mRNA expression and cigarette smoke extracts significantly counteracted this IL-1 mediated effect reducing both the activation of NFkB pathway and the interaction between NFkB and HBD2 promoter. Conclusions: This study provides new insights on the possible mechanisms involved in the alteration of innate immunity mechanisms in COPD. © 2012 Pace et al
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