3,395 research outputs found
Positive culture in allograft ACL-reconstruction: what to do?
The transmission of disease or infection from the donor to the recipient is always a risk with the use of allografts. We carried out a research study on the behavioural pattern of implanted allografts, which were initially stored in perfect conditions (all cultures being negative) but later presented positive cultures at the implantation stage. Because there is no information available on how to deal with this type of situation, our aim was to set guidelines on the course of action which would be required in such a case. We conducted a retrospective study of 181 patients who underwent an ACL reconstruction using BPTB allografts. All previous bone and blood cultures and tests for hepatitis B and C, syphilis and HIV were negative. An allograft sample was taken for culture in the operating theatre just before its implantation. The results of the cultures were obtained 3-5 days after the operation. We had 24 allografts with positive culture (13.25%) after the implantation with no clinical infection in any of these patients. Positive cultures could be caused by undetected contamination while harvesting, storing or during manipulation before implantation. The lack of clinical signs of infection during the follow-up of our patients may indicate that no specific treatment-other than an antibiotic protocol-would be required when facing a case of positive culture of a graft piece after its implantation
Frozen cancellous bone allografts: positive cultures of implanted grafts in posterior fusions of the spine
We have carried out a study on the behaviour pattern of implanted allografts
initially stored in perfect conditions (aseptically processed, culture-negative
and stored at -80 degrees C) but which presented positive cultures at the
implantation stage. There is no information available on how to deal with this
type of situation, so our aim was to set guidelines on the course of action which
would be required in such a case. This was a retrospective study of 112 patients
who underwent a spinal arthrodesis and in whom a total of 189 allograft pieces
were used. All previous bone and blood cultures and tests for hepatitis B and C,
syphilis and HIV (via PCR techniques) were negative. The allografts were stored
by freezing them at -80 degrees C. A sample of the allograft was taken for
culture in the operating theatre just before its implantation in all cases. The
results of the cultures were obtained 3-5 days after the operation. There were 22
allografts with positive culture results (12%) after implantation. These
allografts were implanted in 16 patients (14%). Cultures were positive for
staphylococci coagulase negative (ECN) in 10 grafts (46%), Pseudomonas stutzeri
in two grafts (9%), Corynebacterium jeikeium in two grafts (9%), staphylococci
coagulase positive in two grafts (9%) and for each of the following organisms in
one case each (4%): Corynebacterium spp., Actinomyces odontolyticus,
Streptococcus mitis, Peptostreptococcus spp., Rhodococcus equi and Bacillus spp.
No clinical infection was seen in any of these patients. Positive cultures could
be caused by non-detected contamination at harvesting, storing or during
manipulation before implantation. The lack of clinical signs of infection during
the follow-up of our patients may indicate that no specific treatment different
from our antibiotic protocol is required in the case of positive culture results
of a graft piece after implantation
Stability of the Scalar Potential and Symmetry Breaking in the Economical 3-3-1 Model
A detailed study of the criteria for stability of the scalar potential and
the proper electroweak symmetry breaking pattern in the economical 3-3-1 model,
is presented. For the analysis we use, and improve, a method previously
developed to study the scalar potential in the two-Higgs-doublet extension of
the standard model. A new theorem related to the stability of the potential is
stated. As a consequence of this study, the consistency of the economical 3-3-1
model emerges.Comment: to be published in EPJ C, 13 page
Multifunctional natural forest silviculture economics revised: Challenges in meeting landowners’ and society’s wants: A review
Aim of study: This paper objective focuses on the contribution of multifunctional natural forest silviculture, incorporating both private and public product managements, to forest and woodland economics.
Area of study: Spain and California (USA)
Material and methods: This conceptual article has developed a critical revision of the existing literature on the main economic issues for the multifunctional natural forest silviculture in the last decades.
Main results: Multifunctional natural silviculture has secular roots as a local practice, but as a science of the natural environment applied to the economic management of forest lands it is still in the process of maturation. Timber silviculture remains the central concern of forest economics investment in scientific publications. By contrast, silvicultural modeling of the natural growth of firewood, browse and other non-timber forest products from trees and shrubs receives scant attention in scientific journals. Even rarer are publications on multifunctional natural silviculture for forest and woodland managements, including environmental services geared to people’s active and passive consumption. Under this umbrella, private environmental self-consumption is represented by the amenities enjoyed by private non-industrial landowners. As for environmental public products, the most relevant are carbon, water, mushrooms, recreation, landscape and threatened biodiversity.
Research highlights: This paper is a good example for the conceptual research on forestry techniques and economic concepts applied to multifunctional silviculture in Mediterranean areas of Spain and California. The combination of technical knowledge and private and public economic behaviors definitively contributes to the multifunctional management of natural forest systems
Production of neutral and charged Higgs bosons of the MSSM at the future e-gamma colliders
A complete study for the production of neutral (h^0, H^0, A^0 (= \phi^0_i))
and charged Higgs (H^\pm) bosons at electron-photon colliders is presented in
the context of the minimal supersymmetric standard model.
A particular choice of the non-linear R_\xi gauge is used to evaluate the
amplitudes of the reaction e-gamma --> e \phi^0_i.
The resulting cross section indicates that it will be possible to detect a
signal from the neutral Higgs bosons for most regions of parameter space at the
future linear colliders with \sqrt{s}=500 GeV through the reaction e gamma -->
e \phi^0_i. This reaction also offers the interesting possibility to measure
the Higgs mass through the detection of the outgoing electron.
The production of the charged Higgs boson through the reaction e gamma -->
\nu_e H^\pm$ has in general smaller values for the cross section, which seems
more difficult to observe.Comment: submitted to Phys. Rev.
The Pierre Auger Observatory III: Other Astrophysical Observations
Astrophysical observations of ultra-high-energy cosmic rays with the Pierre
Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference,
Beijing, China, August 201
Operations of and Future Plans for the Pierre Auger Observatory
Technical reports on operations and features of the Pierre Auger Observatory,
including ongoing and planned enhancements and the status of the future
northern hemisphere portion of the Observatory. Contributions to the 31st
International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200
Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV
We describe the measurement of the depth of maximum, Xmax, of the
longitudinal development of air showers induced by cosmic rays. Almost four
thousand events above 10^18 eV observed by the fluorescence detector of the
Pierre Auger Observatory in coincidence with at least one surface detector
station are selected for the analysis. The average shower maximum was found to
evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/-
0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured
shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The
interpretation of these results in terms of the cosmic ray mass composition is
briefly discussed.Comment: Accepted for publication by PR
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