510 research outputs found
The anti-tumor effect of RANKL inhibition in malignant solid tumors - A systematic review
Diabetes mellitus: pathophysiological changes and therap
Persistence of clones of coagulase-negative staphylococci among premature neonates in neonatal intensive care units: two-center study of bacterial genotyping and patient risk factors
From 1 January 1995 until 1 January 1996, we studied the molecular
epidemiology of blood isolates of coagulase-negative staphylococci (CoNS)
in the Neonatal Intensive Care Units (NICUs) of the Sophia Children's
Hospital (SCH; Rotterdam, The Netherlands) and the Wilhelmina Children's
Hospital (WCH; Utrecht, The Netherlands). The main goal of the present
study was to detect putatively endemic clones of CoNS persisting in these
NICUs. Pulsed-field gel electrophoresis was used to detect the possible
presence of endemic clones of clinical significance. In addition, clinical
data of patients in the SCH were analyzed retrospectively to identify risk
factors for the acquisition of positive blood cultures. In both centers,
endemic CoNS clones were persistently present. Thirty-three percent of the
bacterial isolates derived from blood cultures in the SCH belonged to a
single genotype. In the WCH, 45% of all bacterial strains belonged to a
single clone. These clones were clearly different from each other, which
implies that site specificity is involved. Interestingly, we observe that
the clonal type in the SCH differed significantly from the incidentally
occurring strains with respect to both the average pH and partial CO2
pressure of the patient's blood at the time of bacterial culture. We found
that the use of intravascular catheters, low gestational age, and a long
hospital stay were important risk factors for the development of a
putative CoNS infection. When the antibiotic susceptibility of the
bacterial isolates was assessed, a clear correlation between the nature of
the antibiotics most frequently used as a first line of defense versus the
resistance profile was observed. We conclude that the intensive use of
antibiotics in an NICU setting with highly susceptible patients causes
selection of multiresistant clones of CoNS which subsequently become
endemic
Itinerant ferromagnetism in half-metallic CoS_2
We have investigated electronic and magnetic properties of the pyrite-type
CoS_2 using the linearized muffin-tin orbital (LMTO) band method. We have
obtained the ferromagnetic ground state with nearly half-metallic nature. The
half-metallic stability is studied by using the fixed spin moment method. The
non-negligible orbital magnetic moment of Co 3d electrons is obtained as in the local spin density approximation (LSDA). The calculated
ratio of the orbital to spin angular momenta / = 0.15 is
consistent with experiment. The effect of the Coulomb correlation between Co 3d
electrons is also explored with the LSDA + U method. The Coulomb correlation at
Co sites is not so large, eV, and so CoS_2 is possibly
categorized as an itinerant ferromagnet. It is found that the observed
electronic and magnetic behaviors of CoS_2 can be described better by the LSDA
than by the LSDA + U.Comment: 4 pages, 3 postscript figure
5 years of experience implementing a methicillin-resistant Staphylococcus aureus search and destroy policy at the largest university medical center in the Netherlands
OBJECTIVE: To evaluate the effectiveness of a rigorous search and destroy policy for controlling methicillin-resistant Staphylococcus aureus (MRSA) infection or colonization. DESIGN: Hospital-based observational follow-up study. SETTING: Erasmus University Medical Center Rotterdam, a 1,200-bed tertiary care center in Rotterdam, the Netherlands. METHODS: Outbreak control was accomplished by the use of active surveillance cultures for persons at risk, by the preemptive isolation of patients at risk, and by the strict isolation of known MRSA carriers and the eradication of MRSA carriage. For unexpected cases of MRSA colonization or infection, patients placed in strict isolation or contact isolation and healthcare workers (HCWs) were screened. We collected data from 2000-2004. RESULTS: During the 5-year study period, 51,907 MRSA screening culture
High prevalence rate of digestive tract bacteria in duodenoscopes: A nationwide study
Objective Increasing numbers of outbreaks caused by contaminated duodenoscopes used for Endoscopic Retrograde Cholangiopancreatography (ERCP) procedures have been reported, some with fatal outcomes. We conducted a nationwide cross-sectional study to determine the prevalence of bacterial contamination of reprocessed duodenoscopes in The Netherlands. Design All 73 Dutch ERCP centres were invited to sample ≥2 duodenoscopes using centrally distributed kits according to uniform sampling methods, explained by video instructions. Depending on duodenoscope type, four to six sites were sampled and centrally cultured. Contamination was defined as (1) any microorganism with ≥20 colony forming units (CFU)/20 mL (AM20) and (2) presence of microorganisms with gastrointestinal or oral origin, independent of CFU count (MGO). Results Sixty-seven out of 73 centres (92%) sampled 745 sites of 155 duodenoscopes. Ten different duodenoscope types from three distinct manufacturers were sampled including 69 (46%) Olympus TJF-Q180V, 43 (29%) Olympus TJF-160VR, 11 (7%) Pentax ED34-i10T, 8 (5%) Pentax ED-3490TK and 5 (3%) Fujifilm ED-530XT8. Thirty-three (22%) duodenoscopes from 26 (39%) centres were contaminated (AM20). On 23 (15%) duodenoscopes MGO were detected, including Enterobacter cloacae, Escherichia coli, Klebsiella pneumonia and yeasts. For both definitions, contamination was not duodenoscope type dependent (p values: 0.20 and higher). Conclusion In 39% of all Dutch ERCP centres, at least one AM20-contaminated patient-ready duodenoscope was identified. Fifteen per cent of the duodenoscopes harboured MGO, indicating residual organic material of previous patients, that is, failing of disinfection. These results suggest that the present reprocessing and process control procedures are not adequate and safe
Slater-Pauling Behavior of the Half-Ferromagnetic Full-Heusler Alloys
Using the full-potential screened Korringa-Kohn-Rostoker method we study the
full-Heusler alloys based on Co, Fe, Rh and Ru. We show that many of these
compounds show a half-metallic behavior, however in contrast to the
half-Heusler alloys the energy gap in the minority band is extremely small.
These full-Heusler compounds show a Slater-Pauling behavior and the total
spin-magnetic moment per unit cell (M_t) scales with the total number of
valence electrons (Z_t) following the rule: M_t=Z_t-24. We explain why the
spin-down band contains exactly 12 electrons using arguments based on the group
theory and show that this rule holds also for compounds with less than 24
valence electrons. Finally we discuss the deviations from this rule and the
differences compared to the half-Heusler alloys.Comment: 10 pages, 8 figures, revised figure 3, new text adde
From thermal rectifiers to thermoelectric devices
We discuss thermal rectification and thermoelectric energy conversion from
the perspective of nonequilibrium statistical mechanics and dynamical systems
theory. After preliminary considerations on the dynamical foundations of the
phenomenological Fourier law in classical and quantum mechanics, we illustrate
ways to control the phononic heat flow and design thermal diodes. Finally, we
consider the coupled transport of heat and charge and discuss several general
mechanisms for optimizing the figure of merit of thermoelectric efficiency.Comment: 42 pages, 22 figures, review paper, to appear in the Springer Lecture
Notes in Physics volume "Thermal transport in low dimensions: from
statistical physics to nanoscale heat transfer" (S. Lepri ed.
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