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To assess variability in antimicrobial use and associations with infection testing in pediatric ventilator-associated events (VAEs).
Descriptive retrospective cohort with nested case-control study.
Pediatric intensive care units (PICUs), cardiac intensive care units (CICUs), and neonatal intensive care units (NICUs) in 6 US hospitals.
Children≤18 years ventilated for≥1 calendar day.
We identified patients with pediatric ventilator-associated conditions (VACs), pediatric VACs with antimicrobial use for≥4 days (AVACs), and possible ventilator-associated pneumonia (PVAP, defined as pediatric AVAC with a positive respiratory diagnostic test) according to previously proposed criteria.
Among 9,025 ventilated children, we identified 192 VAC cases, 43 in CICUs, 70 in PICUs, and 79 in NICUs. AVAC criteria were met in 79 VAC cases (41%) (58% CICU; 51% PICU; and 23% NICU), and varied by hospital (CICU, 20–67%; PICU, 0–70%; and NICU, 0–43%). Type and duration of AVAC antimicrobials varied by ICU type. AVAC cases in CICUs and PICUs received broad-spectrum antimicrobials more often than those in NICUs. Among AVAC cases, 39% had respiratory infection diagnostic testing performed; PVAP was identified in 15 VAC cases. Also, among AVAC cases, 73% had no associated positive respiratory or nonrespiratory diagnostic test.
Antimicrobial use is common in pediatric VAC, with variability in spectrum and duration of antimicrobials within hospitals and across ICU types, while PVAP is uncommon. Prolonged antimicrobial use despite low rates of PVAP or positive laboratory testing for infection suggests that AVAC may provide a lever for antimicrobial stewardship programs to improve utilization.
Background: A diagnosis of SCD in childhood confers a 200-fold increase in the risk of arterial ischemic stroke. Blood flow velocity measures provide better identification of ischemic risk compared to angiography. This indicates that steno-occlusive arteriopathy is not the singular causative factor. Cerebrovascular reactivity allows for augmentation of cerebral blood flow when needed. Kosinski et al in 2016 demonstrated a direct correlation between CVR and hematocrit levels in SCD. We report a case where CVR persistently normalized in an SCD patient following bone marrow transplant therapy (BMT). Methods: A nine-month-old SCD patient presented with right AIS. Angiography revealed a bilateral Moya-Moya like arteriopathy. A TCD study was normal while a CVR-MRI study revealed markedly impaired reactivity in the entire anterior circulation. Haemaglobin-S at that time was 20.2 %. BMT was performed at age four due to frequent sickle cell crises. Results: One year post-transplant, CVR had dramatically improved in areas previously shown to have impairment (haemoglobin-S 0%). Neuroimaging five years post-transplant showed no further arteriopathy and persistently normalized CVR. Conclusions: BMT therapy resulted in the arrest of progressive intracranial arteriopathy and persistently restored vascular reserve. SCD might not only produce global hematological effects but also triggers local processes such as endothelial dysfunction and vascular inflammation that impair cerebrovascular function.
Adult ventilator-associated event (VAE) definitions include ventilator-associated conditions (VAC) and subcategories for infection-related ventilator-associated complications (IVAC) and possible ventilator-associated pneumonia (PVAP). We explored these definitions for children.
Pediatric, cardiac, or neonatal intensive care units (ICUs) in 6 US hospitals
Patients ≤18 years old ventilated for ≥1 day
We identified patients with pediatric VAC based on previously proposed criteria. We applied adult temperature, white blood cell count, antibiotic, and culture criteria for IVAC and PVAP to these patients. We matched pediatric VAC patients with controls and evaluated associations with adverse outcomes using Cox proportional hazards models.
In total, 233 pediatric VACs (12,167 ventilation episodes) were identified. In the cardiac ICU (CICU), 62.5% of VACs met adult IVAC criteria; in the pediatric ICU (PICU), 54.2% of VACs met adult IVAC criteria; and in the neonatal ICU (NICU), 20.2% of VACs met adult IVAC criteria. Most patients had abnormal white blood cell counts and temperatures; we therefore recommend simplifying surveillance by focusing on “pediatric VAC with antimicrobial use” (pediatric AVAC). Pediatric AVAC with a positive respiratory diagnostic test (“pediatric PVAP”) occurred in 8.9% of VACs in the CICU, 13.3% of VACs in the PICU, and 4.3% of VACs in the NICU. Hospital mortality was increased, and hospital and ICU length of stay and duration of ventilation were prolonged among all pediatric VAE subsets compared with controls.
We propose pediatric AVAC for surveillance related to antimicrobial use, with pediatric PVAP as a subset of AVAC. Studies on generalizability and responsiveness of these metrics to quality improvement initiatives are needed, as are studies to determine whether lower pediatric VAE rates are associated with improvements in other outcomes.
A population of junglerice from Sunflower County, MS, exhibited resistance to fenoxaprop-P-ethyl. An 11-fold difference in ED50 (the effective dose needed to reduce growth by 50%) values was observed when comparing the resistant population (249 g ae ha–1) with susceptible plants (20 g ae ha–1) collected from a different field. The resistant population was controlled by clethodim and sethoxydim at the field rate. Sequencing of the acetyl coenzyme A carboxylase, which encodes the enzyme targeted by fenoxaprop-P-ethyl, did not reveal the presence of any known resistance-conferring point mutations. An enzyme assay confirmed that the acetyl coenzyme A carboxylase in the resistant population is herbicide sensitive. Further investigations with two cytochrome P450 inhibitors, malathion and piperonyl butoxide, and a glutathione-S-transferase inhibitor, 4-chloro-7-nitrobenzofurazan, did not indicate involvement of any metabolic enzymes inhibited by these compounds. The absence of a known target-site point mutation and the sensitivity of the ACCase enzyme to herbicide show that fenoxaprop-P-ethyl resistance in this population is due to a non–target-site mechanism or mechanisms.
Trichinella species are zoonotic nematodes that infect wild carnivores and omnivores throughout the world. We examined the prevalence and species of Trichinella infections in cougars (Puma concolor couguar) from Colorado, United States. Tongues from cougars were examined by pepsin–HCl artificial digestion to detect Trichinella spp. larvae. The species or genotype of individual worms was identified by multiplex polymerase chain reaction (PCR). Trichinella spp. larvae were detected in 17 of 39 cougars (43.6% (28.7–59.5%)). Five of the cougars (12.8%) were infected with T. murrelli, 3 (7.7%) were infected with T. pseudospiralis, and 1 (2.6%) had Trichinella genotype T6. Trichinella spp. larvae from eight cougars were not identified at the species level, due to degraded DNA. The high prevalence of Trichinella spp. in cougars from Colorado and reports of the parasite in other populations of Puma spp. suggest that this large predator is a key mammalian reservoir.
To determine the prevalence and acquisition of extended-spectrum β-lactamases (ESBLs), plasmid-mediated AmpCs (pAmpCs), and carbapenemases (“MDR Enterobacteriaceae”) colonizing children admitted to a pediatric intensive care unit (PICU).
Admission and weekly thereafter rectal surveillance swabs were collected on all pediatric patients during a 6-month study period. Routine phenotypic identification and antibiotic susceptibility testing were performed. Enterobacteriaceae displaying characteristic resistance profiles underwent further molecular characterization to identify genetic determinants of resistance likely to be transmitted on mobile genetic elements and to evaluate relatedness of strains including DNA microarray, multilocus sequence typing, repetitive sequence-based PCR, and hsp60 sequencing typing.
Evaluating 854 swabs from unique children, the overall prevalence of colonization with an MDR Enterobacteriaceae upon admission to the PICU based on β-lactamase gene identification was 4.3% (n=37), including 2.8% ESBLs (n=24), 1.3% pAmpCs (n=11), and 0.2% carbapenemases (n=2). Among 157 pediatric patients contributing 603 subsequent weekly swabs, 6 children (3.8%) acquired an incident MDR Enterobacteriaceae during their PICU stay. One child acquired a pAmpC (E. coli containing blaDHA) related to an isolate from another patient.
Approximately 4% of children admitted to a PICU were colonized with MDR Enterobacteriaceae (based on β-lactamase gene identification) and an additional 4% of children who remained in the PICU for at least 1 week acquired 1 of these organisms during their PICU stay. The acquired MDR Enterobacteriaceae were relatively heterogeneous, suggesting that a single source was not responsible for the introduction of these resistance mechanisms into the PICU setting.
Annual bluegrass resistance to inhibitors of acetolactate synthase (ALS) and photosystem II (PSII) in managed turf has been confirmed in the southeastern United States. A biotype of annual bluegrass that had developed resistance (R) to the PSII inhibitor simazine was not controlled by POST applications of foramsulfuron or trifloxysulfuron in 2011 or 2012. In whole plant dose-response experiments, trifloxysulfuron, simazine, and indaziflam controlled a susceptible (S) population of annual bluegrass > 91% when applied POST to nontillering plants. However, trifloxysulfuron applications at 3.5 to 223 g ai ha−1 only controlled R annual bluegrass ≤ 40%. Similarly, simazine at 140 to 9,000 g ai ha−1 only controlled R annual bluegrass ≤ 20%. R annual bluegrass plants were more tolerant to indaziflam applied POST to leaf stage plants prior to tillering, as rates > 100 g ai ha−1 were needed to control R annual bluegrass ≥ 96%. No differences in the activity of ALS in R and S plants exposed to increasing foramsulfuron concentrations from 0 to 100 µM were detected suggesting that nontarget mechanisms could explain reduced efficacy of POST herbicide applications in whole plant dose-response experiments. Applications of indaziflam (35 to 70 g ha−1) and oxadiazon (2,240 to 4,500 g ai ha−1) effectively controlled R annual bluegrass when applied PRE. This biotype of R annual bluegrass is the first reported instance of a weed developing resistance to multiple modes of action in managed turf. Education is needed among turf managers regarding the consequences of exclusive use of the same herbicides for annual bluegrass control leading to the onset of herbicide resistance.
Seed dormancy can prevent germination under unfavourable conditions that reduce the chances of seedling survival. Freshly harvested seeds often have strong primary dormancy that depends on the temperature experienced by the maternal plant and which is gradually released through afterripening. However, seeds can be induced into secondary dormancy if they experience conditions or cues of future unfavourable conditions. Whether this secondary dormancy induction is influenced by seed-maturation conditions and primary dormancy has not been explored in depth. In this study, we examined secondary dormancy induction in seeds of Arabidopsis thaliana matured under different temperatures and with different levels of afterripening. We found that low water potential and a range of temperatures, from 8°C to 35°C, induced secondary dormancy. Secondary dormancy induction was affected by the state of primary dormancy of the seeds. Specifically, afterripening had a non-monotonic effect on the ability to be induced into secondary dormancy by stratification; first increasing in sensitivity as afterripening proceeded, then declining in sensitivity after 5 months of afterripening, finally increasing again by 18 months of afterripening. Seed-maturation temperature sometimes had effects that were independent of expressed primary dormancy, such that seeds that had matured at low temperature, but which had comparable germination proportions as seeds matured at warmer temperatures, were more easily induced into secondary dormancy. Because seed-maturation temperature is a cue of when seeds were matured and dispersed, these results suggest that the interaction of seed-maturation temperature, afterripening and post-dispersal conditions all combine to regulate the time of year of seed germination.
Hydrogenolysis of n-butane and CO hydrogenation were used to charac-terize the behavior of TiO2 supported Rh in the SMSI state. The Rh was supported on a model support consisting of nonporous spherical particles of TiO2. The simple geometry of the support permits the metal crystallites to be imaged ‘edge-on’ in a transmission electron microscope. This allows detailed examination of the metal surface and the metal-oxide interface as a function of pretreatment. After high temperature reduction in H2, there is no significant change in the morphology of the Rh crystallites. However, the presence of amorphous overlayers 0.2–0.4 nm thick is clearly evident on the Rh surface. These overlayers can only be partially removed after oxidation at 473 K. The presence of these overlayers is well correlated with the drop in hydrogen chemisorption and altered reactivity. While the butane hydrogenolysis activity of Rh is considerably suppressed in the SMSI state, the CO hydrogenation activity is increased by a factor of 3. The H2 uptake and the butane hydrogenolysis activity can be only partially restored after oxidation at 473 K. Treatment at 773 K in oxygen is necessary for restoring the pre-SMSI behavior.
The fabrication and performance characteristics of an integrated distributed feedback (DFB) laser and optical amplifier structure are described. The structure utilizes semi-insulating Fe doped InP layers for current confinement to the active region, electrical isolation between the two sections and for lateral index guiding. The amplified output has a slope of 1 mW/mA of laser current with the amplifier biased at 150 mA which is a factor of 5 larger than that for a typical laser. The laser emits near 1.55 μm and the spectral width under modulation of the amplified output is considerably smaller than that for a DFB laser for the same on/off ratio.
In the next generation of semiconductor devices, minimum dimensions will be smaller, aspect ratios (height to width) of devices features will be larger, and BPSG dielectrics will be challenged to deal with these changes. A new process, which integrates deposition, flow, and anneal of BPSG films, and allows void-free filling of high-aspect-ratio trenches with excellent surface planarization, is presented in this paper. Scanning electron micrographs are used to show the extent of film coverage and planarization. Additional characterization includes ion chromatography, ellipsometry, stress measurements, and breakdown field measurements.
The need for integrated ferroelectrics as charge storage capacitors has increased dramatically not only for use in radiation hardened and commercial non-volatile memories, but also as possible high dielectric material suitable for capacitor applications. These properties combined with a thin film format, offer the capability of forming very compact capacitor structures suitable for MCM applications through Flip-Chip Bonding, or even integrated directly onto MMIC's. In this paper, the material PbZrxTi1-xO3, where x=l, 0.53, and 0.60 has been assessed. Thin films were produced using a sol-gel technique onto metallised thermally oxidised silicon. The effects on film microstructure and crystallinity with variation in the deposition process will be described. The best films were obtained by incorporating excess lead in the starting solutions, and also by the addition of acetylacetone which was used as a solution modifier. It will be demonstrated that fully perovskite films can be readily obtained at temperatures as low as 450°C. The films were normally 0.3-0.44μm thick with grain sizes of the order of 0.2μm. These films exhibited dielectric constants and loss in the range 170-800 and 1-3% respectively. Measurements upto 3MHz, indicated useful performance with low dispersion. The measured Pr and Ec were in the range 16-22μC/cm2, and 60-120kV/cm respectively.
Monolithic colliding pulse mode-locked (CPM) multiple quantum well lasers
generating optical pulses as short as 600 femtoseconds are reported. The CPM
laser is built on a single chip of InGaAs/InGaAsP multiple quantum well
laser. The pulse repetition rates are synchronized with an rf synthesizer up
to 40 GHz in hybrid mode-locking scheme. In passive mode-locking scheme, a
record high repetition rate of 350 GHz has been achieved. All the
sub-picosecond pulses obtained have pulse shapes of sech2 and
transform-limited timebandwidth products between 0.30 to 0.34. This new
optical source is very useful for ultra-high speed optical switching and
optical logic in optical fibers, and ultra-long distance optical soliton
A non-contact and non-destructive laser-based acoustic technique called impulsive stimulated thermal scattering (ISTS) is used to measure thicknesses of films in single-layer and multilayer assemblies such as W/Si, Ti/Si, and Ti/SiO2/Si structures. Thicknesses are determined to within a few percent accuracy with a laboratory version of the measurement apparatus, using conventional large-frame lasers and optics, and in a commercial prototype using compact diode-pumped and diode lasers and optics which all fit onto a 1-ft × 2-ft breadboard. ISTS and conventional measurements (profilometry, SEM, and 4-point resistance) are made on the same samples and the results are found to compare favorably.
A thermal evaporation method was used to obtain SiO2 and CdS/SiO2 nanowires by heating Si substrates coated with a gold thin film in a quartz tube furnace. During growth, pure CdS powder was placed at the heating zone in the furnace, serving as the CdS source for the CdS/SiO2 composite nanowires. It was found that both non-porous and porous Si substrates served as the Si source for the growth of SiO2 nanowires and the CdS/SiO2 composite nanowires. It was also found that the effect of the temperature gradient in the reaction chamber plays an important role in the density distribution of different nanowires (SiO2 or CdS/SiO2 nanowires). The electron field emission properties of these nanowires were investigated using an electron field emission microscope equipped with a Faraday cup.
We describe the first cluster of cases of necrotizing fasciitis (NF) in this century in the United Kingdom (UK). Between 1 January and 30 June 1994 there were six cases (five confirmed, one probable) of Streptococcus pyogenes NF in west Gloucestershire, population 320000. Two cases died. The first two patients probably acquired their infections during the course of elective surgery performed in the same operating theatre, possibly from a nasopharyngeal carrier amongst the theatre staff. The remaining infections were community-acquired. Of 5 S. pyogenes isolates there were 2 M1 strains, 1 M3, 1 M5 and 1 M non-typeable strain. S. pyogenes NF had not been recorded in west Gloucestershire in the preceding 10 years and the incidence of S. pyogenes bacteraemia in England and Wales had not risen in the past 5 years.
The two presumably theatre-acquired infections raised several issues. The need for detailed bacteriological investigation of all cases of post-surgical NF was confirmed. Clusters of S. pyogenes infection following surgery should be managed by closure of the operating theatre until all staff have been screened for carriage. Closure of an operating theatre and screening of staff following a sporadic case is probably not justified because of the infrequency of surgical cross-infection with S. pyogenes. Regular, routine screening of theatre staff is neither practical nor necessary.
Mosquitoes such as Culex quinquefasciatus Say (Diptera: Culicidae) are important vectors of organisms that cause disease in humans. Research into the development of effective standardized odour baits for blood-fed females (oviposition attractants), to enable entomological monitoring of vector populations, is hampered by complex protocols for extraction of physiologically active volatile chemicals from natural breeding site water samples, which have produced inconsistent results. Air entrainment and solvent extraction are technically demanding methods and are impractical for use in resource poor environments where mosquito-borne disease is most prevalent. This study reports the first use of a simple, robust extraction technique, stir bar sorptive extraction (SBSE), to extract behaviourally active small lipophilic molecules (SLMs) present in water samples collected from Cx. quinquefasciatus breeding sites in Tanzania. Extracts from a pit latrine and from a cess pool breeding site attracted more gravid Cx. quinquefasciatus in pair choice bioassays than control extracts, and coupled gas chromatography-electroantennography (GC-EAG) allowed tentative identification of 15 electrophysiologically active chemicals, including the known oviposition attractant, skatole (3-methylindole). Here, we have demonstrated, using simple pair choice bioassays in controlled laboratory conditions, that SBSE is effective for the extraction of behaviourally and electrophysiologically active semiochemicals from mosquito breeding site waters. Further research is required to confirm that SBSE is an appropriate technique for use in field surveys in the search for oviposition cues for Cx. quinquefasciatus.
We investigated language representation in nine children (six male,
three female; 5.6–17.7 years of age) who underwent surgical
treatment of medically intractable epilepsy of the left hemisphere.
Although interhemispheric reorganization has been previously
documented in similar groups, this is the first study to systematically
evaluate possible intrahemispheric effects of early insult. All
cases had left hemisphere seizure foci and underwent extraoperative
stimulation mapping (ESM) for language localization prior to receiving
cortical resections. To compare ESM findings across subjects and to assess
intrahemispheric reorganization, we developed a novel
coregistration technique whereby independent raters plotted
two-dimensional (2D) ESM findings in 3D standard space. Expressive
language sites identified with ESM were compared with a structural
probability map of pars opercularis, or Broca's area. The
average difference between independent raters' estimates of 28
language sites was 3.9 mm (SD = 2.0), indicating excellent agreement; the
coregistration procedure permitted assessment of 2D ESM findings in 3D
standard space. We observed language sites in regions substantially
anterior and superior to canonical Broca's area, possibly reflecting
intrahemispheric reorganization. Findings suggest that left hemisphere
insult in young children may result in anterior displacement of language
within the frontal cortex. (JINS, 2007, 13,
505–516.)This study was drawn from a
thesis submitted by D.S.K. in partial fulfillment of requirements of the
MA degree through the Graduate Program in Psychology and the Collaborative
Program in Neuroscience at the University of Toronto (Ontario,