Selective oropharyngeal decontamination (SOD) and selective decontamination of the digestive tract (SDD) are associated with improved outcomes among patients in intensive care units (ICUs), but ...uncertainty remains about their long-term effects on resistance levels. We determined trends in antibiotic resistance among Gram-negative bacteria in 38 Dutch ICUs using and not using SOD/SDD.
The Infectious Disease Surveillance Information System-Antibiotic Resistance (ISIS-AR) was used to identify all Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter spp. isolates from blood and respiratory tract specimens from ICUs between January 2008 and April 2012. Per patient, the last isolate per species per specimen per month was selected to determine cumulative resistance rates (per 100 beds/month) for colistin, tobramycin, ciprofloxacin, ceftazidime and cefotaxime/ceftriaxone in ICUs that continuously used or did not use SOD/SDD, and ICUs that introduced SOD/SDD. Time trends were analysed by multilevel Poisson regression.
Seventeen ICUs continuously used SOD/SDD (859 months), 13 did not use SOD/SDD (663 months) and 8 introduced SOD/SDD (223 and 117 months before and after introduction). There were no discernible trends in antibiotic resistance among 637 blood isolates. For the 8353 respiratory isolates, resistance to cefotaxime/ceftriaxone increased in ICUs that did not use SOD/SDD (P < 0.001) and decreased in those that continuously used SOD/SDD (P = 0.04), as did resistance to ciprofloxacin (P < 0.001). The introduction of SOD/SDD was followed by statistically significant reductions in resistance rates for all antimicrobial agents.
Continuous use of SOD/SDD was associated with decreasing trends for resistance to cefotaxime/ceftriaxone and ciprofloxacin. The introduction of SOD/SDD was associated with reductions in resistance rates for all antimicrobial agents included.
Objective. The purpose of this study was to investigate in vivo and noninvasively patellar tracking in six degrees of freedom during voluntary knee extension and flexion.
Design. Patellar tracking ...was evaluated in vivo and noninvasively with corroboration using in vivo fluoroscopy and in vitro cadaver measurements.
Background. Patellofemoral pain is closely related to abnormal patellar tracking and malalignment. However, there is a lack of quantitative and convenient methods to evaluate six degrees of freedom in vivo patellar tracking, partly due to difficulty in evaluating 3-D patellar tracking noninvasively.
Methods. Six degrees of freedom patellar tracking was measured in vivo and noninvasively using a small clamp mounted onto the patella and an optoelectronic motion capture system in 18 knees of 12 healthy subjects during voluntary knee extension and flexion.
Results. The patella tracked systematically following a certain pattern during knee extension and flexion. Patellar tracking patterns during knee extension and flexion were not significantly different in the 18 knees tested. When the knee was voluntarily extended from 15° flexion to full extension, the patella was extended 8°, laterally tilted 2°, and shifted 3 mm laterally and 10 mm proximally. The results were consistent with previous in vitro and in vivo studies.
Conclusions. Six degrees of freedom patellar tracking can be evaluated in vivo and noninvasively within the range of 20° flexion to full knee extension.
Relevance
The study provided us quantitative six degrees of freedom information about patellar tracking during knee flexion/extension, which can be used to investigate patellar tracking in vivo and noninvasively in both healthy subjects and patients with patellofemoral disorder and patellar malalignment.
HK022 is a temperate coliphage related to phage lambda. Its chromosome has been completely sequenced, and several aspects of its life cycle have been intensively studied. In the overall arrangement, ...expression, and function of most of its genes, HK022 broadly resembles lambda and other members of the lambda family. Upon closer view, significant differences emerge. The differences reveal alternative strategies used by related phages to cope with similar problems and illuminate previously unknown regulatory and structural motifs. HK022 prophages protect lysogens from superinfection by producing a sequence-specific RNA binding protein that prematurely terminates nascent transcripts of infecting phage. It uses a novel RNA-based mechanism to antiterminate its own early transcription. The HK022 protein shell is strengthened by a complex pattern of covalent subunit interlinking to form a unitary structure that resembles chain-mail armour. Its integrase and repressor proteins are similar to those of lambda, but the differences provide insights into the evolution of biological specificity and the elements needed for construction of a stable genetic switch.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The common laboratory strain of bacteriophage λ-λ wild type or λPaPa-carries a frameshift mutation relative to Ur-λ, the original isolate. The Ur-λ virions have thin, jointed tail fibers that are ...absent from λ wild type. Two novel proteins of Ur-λ constitute the fibers: the product of stf, the gene that is disrupted in λ wild type by the frameshift mutation, and the product of gene tfa, a protein that is implicated in facilitating tail fiber assembly. Relative to λ wild type, Ur-λ has expanded receptor specificity and adsorbs to Escherichia coli cells more rapidly.
Muscle strength in knee varus and valgus ZHANG, Li-Qun; DALI XU; GUANGZHI WANG ...
Medicine and science in sports and exercise,
07/2001, Letnik:
33, Številka:
7
Journal Article
Recenzirano
Odprti dostop
The purpose of this study was to investigate the lower-limb muscle strength in knee varus-valgus and its dependence on knee varus-valgus position. The hypothesis was that humans could differentially ...contract the medial and lateral muscles crossing the knee and generate significant moments in knee valgus-varus.
The subjects sat with the knee at full extension and secured from the medial, lateral, anterior, and posterior sides. Both hips were clamped from the lateral sides. The subjects adducted (abducted) the ipsilateral hip during the knee valgus (varus) maximal voluntary contraction with EMG signals recorded from muscles crossing the knee and knee joint moments measured using a six-axis force sensor. Frontal plane tibiofemoral movement was evaluated using a fluoroscope.
The subjects differentially contracted the medial and lateral muscles, and fluoroscope images showed the corresponding tibiofemoral movement. The subjects showed considerable strength in knee varus and valgus. The active knee varus strength increased significantly with increasing knee valgus angle, and the valgus strength was significantly higher when the knee was in varus position (P < 0.039). Active valgus muscle strength at 5 degrees knee varus was significantly higher than the active varus strength at 5 degrees valgus (P = 0.002). The passive resistance moment increased linearly with increasing knee valgus and varus angles, and it accounted for 28% and 35% of the total (active plus passive) moment at the 5 degrees varus and 5 degrees valgus, respectively. The significant varus-valgus muscle strength demonstrated in this study may play important roles in performing various functional tasks, maintaining joint stability, and preventing potential injuries, whether the major load and motion at the knee is in the frontal plane or not.
Bacteriophage HK97 builds its head shell from a 42 kDa major head protein, but neither this 42 kDa protein nor its processed, 31 kDa form is found in the mature head. Instead, each of the major ...head-protein subunits is covalently cross-linked into oligomers of five, six or more by a protein cross-linking reaction that occurs both
in vivo and
in vitro. Mutants that block prohead maturation lead to the accumulation of one of two types of proheads, termed Prohead I and Prohead II. Prohead I is assembled from about 415 copies of the 42 kDa (384 amino acids) protein subunit and accumulates in infections by mutant
amU4. Following assembly, the N-terminal 102 amino acids of each subunit are removed, leaving a prohead shell constructed of 31 kDa subunits, called Prohead II, which accumulates in infections by mutant
amC2. During DNA packaging, when the prohead shell expands, all of the head protein subunits become covalently cross-linked to other subunits. Purified Prohead II (or, less completely, Prohead I) becomes cross-linked
in vitro in response to any of a number of conditions that induce shell expansion, including conditions commonly used for protein analysis.
In vitro cross-linking occurs efficiently in the absence of added cofactors of enzymes, and we propose that cross-linking is catalyzed by shell subunits themselves. Shell expansion is easily monitored by observing a decrease in electrophoretic mobility of Prohead II in agarose gels. Using the mobility shift in agarose gel to monitor expansion and SDS/gel electrophoresis to monitor cross-linking
in vitro, we find that expansion precedes and is required for cross-linking, and we propose that expansion
triggers the cross-linking reaction. Comparison of peptides isolated from Prohead II and
in vitro cross-linked Prohead II shows a single altered major cross-link peptide in which a lysine, originating from lysine169 of the protein sequence, is linked to asparagine356, presumably derived from the neighboring subunit. Examination of the cross-link-containing peptide by mass spectrometry shows that the cross-link bond is an amide between the side-chains of the lysine and the asparagine residues.
A building block strategy for modelling the pressure loss coefficient of flow through a complex geometry is presented. The approach relies on decomposing a complex flow geometry into geometrical ...building blocks of which the pressure loss coefficients are characterized individually. The different contributions are subsequently combined to describe the pressure loss of the geometry as a whole. This approach is applied and tested to an industrially relevant application: a by-pass pig (Pipeline Inspection Gauge). This is a cylindrical device that travels inside a pipeline and is commonly used in the oil and gas industry for pipeline maintenance. An important factor in determining the ultimate velocity of the device is the pressure drop over the by-pass pig, which is characterized by a pressure loss coefficient due to the by-passing fluids. In this study the pressure loss coefficient of three frequently used by-pass pig geometries in a single phase pipeline is investigated with Computational Fluid Dynamics (CFD). The CFD results are used to validate the simple building block approach for systematic modelling of the pressure loss through the by-pass pigs, which takes the geometry and size of the by-pass opening into account. It is shown that the pressure loss models can capture the CFD results for each of the three pig geometries. The pressure loss models can be combined with pig/pipe-wall friction models to predict the velocity of a by-pass pig in a single phase pipeline, which is important for a safe and effective pigging operation. The applied building block approach may also be suitable to characterize pressure loss coefficients of complex geometries in general.
•A building block approach is described to model the pressure loss coefficient of a complex geometry.•The approach is applied to an industrially relevant application: a by-pass pig.•CFD is used to validate the proposed building block approach, good agreement was found.
Worldwide, anthropogenic disturbance has contributed to reductions in native earthworm abundance and diversity and subsequent establishment of exotic populations. Exotic earthworm species dominate ...the earthworm community primarily in nutrient-enriched soils characteristic of urbanized and rural areas, while native species persist in less disturbed habitat. We hypothesized that exotic species may displace native species through competitive interactions, but only under conditions of high resource availability. To test this we manipulated both grassland productivity and the presence and density of intra- and interspecific competitors in field and laboratory experiments with two common species, the native megascolecid
Argilophilus marmoratus Eisen 1893 and the exotic lumbricid
Aporrectodea trapezoides Dugés 1828.
Overall,
Ap. trapezoides maintained greater relative growth than
Ar. marmoratus. The difference in growth between the two species declined with decreasing habitat quality, primarily due to lower relative growth of
Ap. trapezoides in less productive grasslands. As the competitor species,
Ap. trapezoides had a negative effect on both itself and
Ar. marmoratus in all habitat types, while
Ar. marmoratus as competitor had a more neutral effect. Reproductive development followed the same general pattern, but to become reproductive
Ap. trapezoides required almost double the amount of relative growth as
Ar. marmoratus. Both species had a negative effect on potential food resources, including microbial biomass and belowground plant biomass, but
Ap. trapezoides reduced resources more than
Ar. marmoratus in all habitat types.
Ap. trapezoides achieved a greater relative growth than
Ar. marmoratus in soils with high resource availability, but it lost proportionally more mass as resources declined. Thus,
Ap. trapezoides attempting to colonize less productive grasslands may simply deplete available resources and fail to achieve sufficient growth for reproductive development. Our results suggest that interspecific competition has the potential to prevent
Ar. marmoratus from recolonizing pastures dominated by
Ap. trapezoides. Both species respond to enhanced resources in these pastures, but in resource-rich habitats
Ap. trapezoides may exclude
Ar. marmoratus through greater and faster growth per unit resource consumption coupled with earlier onset of reproduction.
Ar. marmoratus is the weaker competitor of the two, but its negative effect on
Ap. trapezoides in less productive grassland may exacerbate the role of resource limitation in preventing
Ap. trapezoides from expanding its range.
We have identified promoters for the Escherichia coli heat shock operons dnaK and groE and the gene encoding heat shock protein C62.5. Transcription from each promoter is heat-inducible in vivo, and ...each is recognized in vitro by RNA polymerase containing σ32, the σ factor encoded by rpoH (htpR) but not by RNA polymerase containing σ70. We compared the sequences of the heat shock promoters and propose a consensus promoter sequence, having T-N-t-C-N-C-c-C-T-T-G-A-A in the -35 region and C-C-C-C-A-T-t-T-a in the -10 region. These sequences differ from the consensus sequence recognized by holoenzyme containing σ70, the major σ in E. coli. We suggest that the accumulated consensus sequences of promoters recognized by alternate forms of holoenzyme are compatible with a model in which σ recognizes only the -10 region of the promoter.
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