21 research outputs found
Analysis of Downhole Logs, Leg 57, Deep Sea Drilling Project
All sites drilled on Leg 57 were logged as weather
conditions permitted. The logging was done by the Singapore
office of Schlumberger, and because of short
notice the special logging tools required to pass through
the Challenger drill pipe were not available. The standard
centralizer, excentralizer, and caliper tools were
not appropriate, and those modified aboard ship were
not completely satisfactory. In addition, we suspected
that vertical motion from the ship's heave degraded the
quality of logs. Both the sonic and neutron density tools
were operated beyond their normal working ranges. Despite
these operational difficulties, the logs from different
runs in a hole, both repeat sections and runs with
different tools, show generally the same features. Over
intervals of 5 to 10 meters the field logs seem to be good
indicators of the physical character of the section penetrated
(Carson and Bruns, this volume).
The recovery of continuous core as well as logs differs
from normal industrial drilling practice, in which a
major purpose of logging is to establish lithology. Since
lithology is best established by direct examination, the
log analysis focused less on identifying a specific lithology
than on continuous measurement of in situ
physical properties, especially at Sites 438, 439, and 440,
where recovery was good. However, the logs were used
to establish the lithology of missing intervals, especially
at Site 441, where recovery was poor. Lithology and
physical properties aspects of the log analysis are covered
in the individual site chapters and in a comparative
analysis of laboratory measurements of physical properties
and logged physical parameters (Carson and Bruns,
this volume). In the present chapter we concentrate on
log precision, correlation of key horizons in seismic
records and core lithology, and on fracturing as indicated
by the logs. We do this by using the results of a
study of corrected logs and the derivative products from
computer programs developed by the Scientific Software
Corporation (SSC) and Technology Research Center
and of corrected logs from Schlumberger (available
from DSDP)
Interpretation of Multichannel Seismic Reflection Data, Legs 56 and 57, Japan Trench Transect, Deep Sea Drilling Project
Studies of convergent margin tectonics along the Japan Trench Transect are based on geophysical as well as on drill and conventional sampling data. The large number of geophysical and geological studies in the 1960's made this area an attractive target for convergent margin drill core sampling. Once the transect was scheduled for drilling by the Glomar Challenger, the earth science community in Japan intensified its efforts to collect geophysical and geological data within the transect area. Many of these data are published in Japanese and international journals. This chapter describes both the seismic reflection records along which Legs 56 and 57 drilling took place and the reflection records made after drilling. The seismic data are interpreted in light of the drilling results
Occurrence of Corynebacterium striatum as an emerging antibiotic-resistant nosocomial pathogen in a Tunisian hospital
Corynebacterium striatum is a nosocomial opportunistic pathogen increasingly associated with a wide range of human infections and is often resistant to several antibiotics. We investigated the susceptibility of 63 C. striatum isolated at the Farhat-Hached hospital, Sousse (Tunisia), during the period 2011?2014, to a panel of 16 compounds belonging to the main clinically relevant classes of antimicrobial agents. All strains were susceptible to vancomycin, linezolid, and daptomycin. Amikacin and gentamicin also showed good activity (MICs90 = 1 and 2 mg/L, respectively). High rates of resistance to penicillin (82.5%), clindamycin (79.4%), cefotaxime (60.3%), erythromycin (47.6%), ciprofloxacin (36.5%), moxifloxacin (34.9%), and rifampicin (25.4%) were observed. Fifty-nine (93.7%) out of the 63 isolates showed resistance to at least one compound and 31 (49.2%) were multidrug-resistant. Twenty-nine resistance profiles were distinguished among the 59 resistant C. striatum. Most of the strains resistant to fluoroquinolones showed a double mutation leading to an amino acid change in positions 87 and 91 in the quinolone resistance-determining region of the gyrA gene. The 52 strains resistant to penicillin were positive for the gene bla, encoding a class A ?-lactamase. Twenty-two PFGE patterns were identified among the 63 C. striatum, indicating that some clones have spread within the hospital
Enzymatic Mechanisms Involved in Evasion of Fungi to the Oxidative Stress: Focus on Scedosporium apiospermum
The airways of patients with cystic fibrosis (CF) are frequently colonized by various filamentous fungi, mainly Aspergillus fumigatus and Scedosporium species. To establish within the respiratory tract and cause an infection, these opportunistic fungi express pathogenic factors allowing adherence to the host tissues, uptake of extracellular iron, or evasion to the host immune response. During the colonization process, inhaled conidia and the subsequent hyphae are exposed to reactive oxygen species (ROS) and reactive nitrogen species (RNS) released by phagocytic cells, which cause in the fungal cells an oxidative stress and a nitrosative stress, respectively. To cope with these constraints, fungal pathogens have developed various mechanisms that protect the fungus against ROS and RNS, including enzymatic antioxidant systems. In this review, we summarize the different works performed on ROS- and RNS-detoxifying enzymes in fungi commonly encountered in the airways of CF patients and highlight their role in pathogenesis of the airway colonization or respiratory infections. The potential of these enzymes as serodiagnostic tools is also emphasized. In addition, taking advantage of the recent availability of the whole genome sequence of S. apiospermum, we identified the various genes encoding ROS- and RNS-detoxifying enzymes, which pave the way for future investigations on the role of these enzymes in pathogenesis of these emerging species since they may constitute new therapeutics targets
Irreversible phase transitions due to laser-based T-jump heating of precursor Eu:ZrO2/Tb:Y2O3 core/shell nanoparticles
Amorphous precursors of Eu-doped-ZrO2/Tb-doped-Y2O3 (p-Eu:ZrO2/p-Tb:Y2O3) core/shell nanoparticles are rapidly heated to temperatures between 200 degrees C and 950 degrees C for periods between 2 s and 60 s using a CO2 laser. During this heating process the nanoparticles undergo irreversible phase changes. The fluorescence spectra due to Eu3+ dopants in the core and Tb3+ dopants in the shell are used to identify distinct phases within the material and to generate time/temperature phase diagrams. Such phase diagrams can potentially help to determine unknown time/temperature histories in thermosensor applications. (C) 2015 Elsevier Inc. All rights reserved
A Clinical Comparative Study of Piperacillin and Sulbactam/Ampicillin in Patients with Community-Acquired Bacterial Pneumonia
Objective To evaluate the clinical usefulness of piperacillin (4 g/day) therapy for community-acquired pneumonia compared to sulbactam/ampicillin (6 g/day). Methods A randomized prospective clinical study was conducted in patients with mild to severe community-acquired bacterial pneumonia. Results The overall clinical efficiency of piperacillin therapy (4 g/day) in these patients (41/53=77.4%) was comparable to that of sulbactam/ampicillin therapy (6 g/day: efficiency rate: 33/49=67.3%), when each therapy was administered intravenously for 3-7 days. With regards to clinical efficiency based on disease severity, bacteriological efficiency, improvement in chest X-ray findings and adverse reactions, the two therapies were comparable, even though we found more efficiency for patients who had underlying diseases and there were also cost benefits in piperacillin therapy, compared with sulbactam/ampicillin therapy Conclusion The results suggested that piperacillin therapy has good efficiency and tolerability and that it may be highly effective, even in cases of pneumonia with underlying diseases. This regimen may thus serve as a first line treatment of community-acquired pneumonia