bluuebunny/crossref_metadata_2025_split huggingface dataset:
Monitoring local heating around an interventional MRI antenna with RF radiometry
Authors: Ertürk M. Arcan , El‐Sharkawy AbdEl‐Monem M. , Bottomley Paul A. 
Published: February 2015

Purpose:Radiofrequency (RF) radiometry uses thermal noise detected by an antenna to measure the temperature of objects independent of medical imaging technologies such as magnetic resonance imaging (MRI). Here, an active interventional MRI antenna can be deployed as a RF radiometer to measure local heating, as a possible new method of monitoring device safety and thermal therapy.Methods:A 128 MHz radiometer receiver was fabricated to measure the RF noise voltage from an interventional 3 T MRI loopless antenna and calibrated for temperature in a uniformly heated bioanalogous gel phantom. Local heating (ΔT) was induced using the antenna for RF transmission and measured by RF radiometry, fiber‐optic thermal sensors, and MRI thermometry. The spatial thermal sensitivity of the antenna radiometer was numerically computed using a method‐of‐moment electric field analyses. The gel's thermal conductivity was measured by MRI thermometry, and the localized time‐dependent ΔT distribution computed from the bioheat transfer equation and compared with radiometry measurements. A “H‐factor” relating the 1 g‐averaged ΔT to the radiometric temperature was introduced to estimate peak temperature rise in the antenna's sensitive region.Results:The loopless antenna radiometer linearly tracked temperature inside a thermally equilibrated phantom up to 73 °C to within ±0.3 °C at a 2 Hz sample rate. Computed and MRI thermometric measures of peak ΔT agreed within 13%. The peak 1 g‐average temperature was H = 1.36 ± 0.02 times higher than the radiometric temperature for any media with a thermal conductivity of 0.15–0.50 (W/m)/K, indicating that the radiometer can measure peak 1 g‐averaged ΔT in physiologically relevant tissue within ±0.4 °C.Conclusions:Active internal MRI detectors can serve as RF radiometers at the MRI frequency to provide accurate independent measures of local and peak temperature without the artifacts that can accompany MRI thermometry or the extra space needed to accommodate alternative thermal transducers. A RF radiometer could be integrated in a MRI scanner to permit “self‐monitoring” for assuring device safety and/or monitoring delivery of thermal therapy.
Segmentation of myocardium from cardiac MR images using a novel dynamic programming based segmentation method
Authors: Qian Xiaohua , Lin Yuan , Zhao Yue , Wang Jing , Liu Jing , Zhuang Xiahai 
Published: February 2015

Purpose:Myocardium segmentation in cardiac magnetic resonance (MR) images plays a vital role in clinical diagnosis of the cardiovascular diseases. Because of the low contrast and large variation in intensity and shapes, myocardium segmentation has been a challenging task. A dynamic programming (DP) based segmentation method, incorporating the likelihood and shape information of the myocardium, is developed for segmenting myocardium in cardiac MR images.Methods:The endocardium, i.e., the left ventricle blood cavity, is segmented for initialization, and then the optimal epicardium contour is determined using the polar‐transformed image and DP scheme. In the DP segmentation scheme, three techniques are proposed to improve the segmentation performance: (1) the likelihood image of the myocardium is constructed to define the external cost in the DP, thus the cost function incorporates prior probability estimation; (2) the adaptive search range is introduced to determine the polar‐transformed image, thereby excluding irrelevant tissues; (3) the connectivity constrained DP algorithm is developed to obtain an optimal closed contour. Four metrics, including the Dice metric (Dice), root mean squared error (RMSE), reliability, and correlation coefficient, are used to assess the segmentation accuracy. The authors evaluated the performance of the proposed method on a private dataset and the MICCAI 2009 challenge dataset. The authors also explored the effects of the three new techniques of the DP scheme in the proposed method.Results:For the qualitative evaluation, the segmentation results of the proposed method were clinically acceptable. For the quantitative evaluation, the mean (Dice) for the endocardium and epicardium was 0.892 and 0.927, respectively; the mean RMSE was 2.30 mm for the endocardium and 2.39 mm for the epicardium. In addition, the three new techniques in the proposed DP scheme, i.e., the likelihood image of the myocardium, the adaptive search range, and the connectivity constrained DP algorithm, improved the segmentation performance for the epicardium with 0.029, 0.047, and 0.007 in terms of the Dice and 0.98, 1.31, and 0.21 mm in terms of the RMSE, respectively.Conclusions:The three techniques (the likelihood image of the myocardium, the adaptive search range, and the connectivity constrained DP algorithm) can improve the segmentation ability of the DP method, and the proposed method with these techniques has the ability to achieve the acceptable segmentation result of the myocardium in cardiac MR images. Therefore, the proposed method would be useful in clinical diagnosis of the cardiovascular diseases.
Dynamic Postural Control Two Years Following Anterior Cruciate Ligament Reconstruction in a Female Collegiate Soccer Player
Authors: Samaan Michael A. , Greska Eric K. , Hoch Matthew C. , Weinhandl Joshua T. , Bawab Sebastian Y. , Ringleb Stacie I. 
Published: March 2015

Context:ACL injury may cause a lack of knee joint proprioception and motor control due to knee joint instability. ACL reconstruction restores knee joint stability, yet dynamic postural control may still be affected while performing dynamic tasks.Objective:To examine the effects of ACL injury and reconstruction on dynamic postural control using the Star Excursion Balance Test (SEBT) and single leg hop (SLH).Participant:One Division I female athlete.Main Outcome Measure:The athlete’s dynamic postural control, both pre- and postreconstruction, was compared with preinjury data using the method of minimal detectable change using reach distances obtained from the SEBT and hop distances from the SLH.Results:ACL injury and reconstruction affected the anterior, posteromedial, and posterolateral reach distances of the SEBT. Despite restoration of joint stability, anterior reach distance in the SEBT did not return to preinjury levels 27 months after ACL reconstruction. SLH distances decreased following injury but returned to preinjury levels 27 months after ACL reconstruction.Conclusion:Dynamic postural control and performance during the SEBT and SLH were affected by ACL injury and for extended periods of time after ACL reconstruction. Quadriceps inhibition and muscle strength of the involved limb may affect dynamic postural control both after ACL injury and reconstruction while performing the SEBT. Compensatory mechanisms at the hip and ankle may aid in performance of the SLH after reconstruction. Using baseline measurements, where possible, may help researchers better understand the effects of ACL injury and reconstruction on dynamic postural control.
Serratus Anterior Muscle Activation During Different Push-up Exercises: A Critically Appraised Topic
Authors: Meier Taylor , Snyder Brice , Cuchna Jennifer W. , Hoch Johanna M. 
Published: March 2015

Clinical Question:In a healthy adult population, which push-up position produces the greatest mean serratus anterior (SA) activation, expressed as a percentage of maximum voluntary isometric contraction (MVIC)?Clinical Bottom Line:In a healthy population, there is moderate evidence to support the use of the standard push-up on an unstable surface, elbow push-ups on stable and unstable surfaces, wall push-ups on an unstable surface, the full weight-bearing position using the Cuff Link system, and all three hand positions (shoulder width, wide base, and narrow base) with and without the use of the Perfect Pushup™ handgrips for the purpose of SA strengthening. These exercises produced a mean SA activation of at least 50% of the MVIC in the four cross-sectional studies that were reviewed for this critically appraised topic.
Development of the Honey Bee Gut Microbiome throughout the Queen-Rearing Process
Authors: Tarpy David R. , Mattila Heather R. , Newton Irene L. G. 
Published: February 2015

ABSTRACT

The European honey bee (
Apis mellifera
) is used extensively to produce hive products and for crop pollination, but pervasive concerns about colony health and population decline have sparked an interest in the microbial communities that are associated with these important insects. Currently, only the microbiome of workers has been characterized, while little to nothing is known about the bacterial communities that are associated with queens, even though their health and proper function are central to colony productivity. Here, we provide a large-scale analysis of the gut microbiome of honey bee queens during their developmental trajectory and through the multiple colonies that host them as part of modern queen-rearing practices. We found that queen microbiomes underwent a dramatic shift in size and composition as they aged and encountered different worker populations and colony environments. Queen microbiomes were dominated by enteric bacteria in early life but were comprised primarily of alphaproteobacteria at maturity. Furthermore, queen gut microbiomes did not reflect those of the workers who tended them and, indeed, they lacked many of the bacteria that are considered vital to workers. While worker gut microbiotas were consistent across the unrelated colony populations sampled, the microbiotas of the related queens were highly variable. Bacterial communities in mature queen guts were similar in size to those of mature workers and were characterized by dominant and specific alphaproteobacterial strains known to be associated with worker hypopharyngeal glands. Our results suggest a model in which queen guts are colonized by bacteria from workers' glands, in contrast to routes of maternal inoculation for other animal microbiomes.
Pseudomonas fluorescens Pirates both Ferrioxamine and Ferricoelichelin Siderophores from Streptomyces ambofaciens
Authors: Galet Justine , Deveau Aurélie , Hôtel Laurence , Frey-Klett Pascale , Leblond Pierre , Aigle Bertrand 
Published: February 2015

ABSTRACT

Iron is essential in many biological processes. However, its bioavailability is reduced in aerobic environments, such as soil. To overcome this limitation, microorganisms have developed different strategies, such as iron chelation by siderophores. Some bacteria have even gained the ability to detect and utilize xenosiderophores, i.e., siderophores produced by other organisms. We illustrate an example of such an interaction between two soil bacteria,
Pseudomonas fluorescens
strain BBc6R8 and
Streptomyces ambofaciens
ATCC 23877, which produce the siderophores pyoverdine and enantiopyochelin and the siderophores desferrioxamines B and E and coelichelin, respectively. During pairwise cultures on iron-limiting agar medium, no induction of siderophore synthesis by
P. fluorescens
BBc6R8 was observed in the presence of
S. ambofaciens
ATCC 23877. Cocultures with a
Streptomyces
mutant strain that produced either coelichelin or desferrioxamines, as well as culture in a medium supplemented with desferrioxamine B, resulted in the absence of pyoverdine production; however, culture with a double mutant deficient in desferrioxamines and coelichelin production did not. This strongly suggests that
P. fluorescens
BBbc6R8 utilizes the ferrioxamines and ferricoelichelin produced by
S. ambofaciens
as xenosiderophores and therefore no longer activates the production of its own siderophores. A screening of a library of
P. fluorescens
BBc6R8 mutants highlighted the involvement of the TonB-dependent receptor FoxA in this process: the expression of
foxA
and genes involved in the regulation of its biosynthesis was induced in the presence of
S. ambofaciens
. In a competitive environment, such as soil, siderophore piracy could well be one of the driving forces that determine the outcome of microbial competition.
Mono- and Dialkyl Glycerol Ether Lipids in Anaerobic Bacteria: Biosynthetic Insights from the Mesophilic Sulfate Reducer Desulfatibacillum alkenivorans PF2803
T
Authors: Grossi Vincent , Mollex Damien , Vinçon-Laugier Arnauld , Hakil Florence , Pacton Muriel , Cravo-Laureau Cristiana 
Published: February 2015

ABSTRACT

Bacterial glycerol ether lipids (alkylglycerols) have received increasing attention during the last decades, notably due to their potential role in cell resistance or adaptation to adverse environmental conditions. Major uncertainties remain, however, regarding the origin, biosynthesis, and modes of formation of these uncommon bacterial lipids. We report here the preponderance of monoalkyl- and dialkylglycerols (1-
O
-alkyl-, 2-
O
-alkyl-, and 1,2-
O
-dialkylglycerols) among the hydrolyzed lipids of the marine mesophilic sulfate-reducing proteobacterium
Desulfatibacillum alkenivorans
PF2803
T
grown on
n
-alkenes (pentadec-1-ene or hexadec-1-ene) as the sole carbon and energy source. Alkylglycerols account for one-third to two-thirds of the total cellular lipids (alkylglycerols plus acylglycerols), depending on the growth substrate, with dialkylglycerols contributing to one-fifth to two-fifths of the total ether lipids. The carbon chain distribution of the lipids of
D. alkenivorans
also depends on that of the substrate, but the chain length and methyl-branching patterns of fatty acids and monoalkyl- and dialkylglycerols are systematically congruent, supporting the idea of a biosynthetic link between the three classes of compounds. Vinyl ethers (1-alken-1′-yl-glycerols, known as plasmalogens) are not detected among the lipids of strain PF2803
T
. Cultures grown on different (per)deuterated
n
-alkene,
n
-alkanol, and
n
-fatty acid substrates further demonstrate that saturated alkylglycerols are not formed via the reduction of hypothetic alken-1′-yl intermediates. Our results support an unprecedented biosynthetic pathway to monoalkyl/monoacyl- and dialkylglycerols in anaerobic bacteria and suggest that
n
-alkyl compounds present in the environment can serve as the substrates for supplying the building blocks of ether phospholipids of heterotrophic bacteria.
Role of Phosphatidylinositol Phosphate Signaling in the Regulation of the Filamentous-Growth Mitogen-Activated Protein Kinase Pathway
Authors: Adhikari Hema , Cullen Paul J. 
Published: February 2015

ABSTRACT

Reversible phosphorylation of the phospholipid phosphatidylinositol (PI) is a key event in the determination of organelle identity and an underlying regulatory feature in many biological processes. Here, we investigated the role of PI signaling in the regulation of the mitogen-activated protein kinase (MAPK) pathway that controls filamentous growth in yeast. Lipid kinases that generate phosphatidylinositol 4-phosphate [PI(4)P] at the Golgi (Pik1p) or PI(4,5)P2 at the plasma membrane (PM) (Mss4p and Stt4p) were required for filamentous-growth MAPK pathway signaling. Introduction of a conditional allele of
PIK1
(
pik1-83
) into the filamentous (Σ1278b) background reduced MAPK activity and caused defects in invasive growth and biofilm/mat formation. MAPK regulatory proteins that function at the PM, including Msb2p, Sho1p, and Cdc42p, were mislocalized in the
pik1-83
mutant, which may account for the signaling defects of the PI(4)P kinase mutants. Other PI kinases (Fab1p and Vps34p), and combinations of PIP (synaptojanin-type) phosphatases, also influenced the filamentous-growth MAPK pathway. Loss of these proteins caused defects in cell polarity, which may underlie the MAPK signaling defect seen in these mutants. In line with this possibility, disruption of the actin cytoskeleton by latrunculin A (LatA) dampened the filamentous-growth pathway. Various PIP signaling mutants were also defective for axial budding in haploid cells, cell wall construction, or proper regulation of the high-osmolarity glycerol response (HOG) pathway. Altogether, the study extends the roles of PI signaling to a differentiation MAPK pathway and other cellular processes.
Control of Plasma Membrane Permeability by ABC Transporters
Authors: Khakhina Svetlana , Johnson Soraya S. , Manoharlal Raman , Russo Sarah B. , Blugeon Corinne , Lemoine Sophie , Sunshine Anna B. , Dunham Maitreya J. , Cowart L. Ashley , Devaux Frédéric , Moye-Rowley W. Scott 
Published: February 2015

ABSTRACT

ATP-binding cassette transporters Pdr5 and Yor1 from
Saccharomyces cerevisiae
control the asymmetric distribution of phospholipids across the plasma membrane as well as serving as ATP-dependent drug efflux pumps. Mutant strains lacking these transporter proteins were found to exhibit very different resistance phenotypes to two inhibitors of sphingolipid biosynthesis that act either late (aureobasidin A [AbA]) or early (myriocin [Myr]) in the pathway leading to production of these important plasma membrane lipids. These
pdr5Δ yor1
strains were highly AbA resistant but extremely sensitive to Myr. We provide evidence that these phenotypic changes are likely due to modulation of the plasma membrane flippase complexes, Dnf1/Lem3 and Dnf2/Lem3. Flippases act to move phospholipids from the outer to the inner leaflet of the plasma membrane. Genetic analyses indicate that
lem3
Δ mutant strains are highly AbA sensitive and Myr resistant. These phenotypes are fully epistatic to those seen in
pdr5Δ yor1
strains. Direct analysis of AbA-induced signaling demonstrated that loss of Pdr5 and Yor1 inhibited the AbA-triggered phosphorylation of the AGC kinase Ypk1 and its substrate Orm1. Microarray experiments found that a
pdr5Δ yor1
strain induced a Pdr1-dependent induction of the entire Pdr regulon. Our data support the view that Pdr5/Yor1 negatively regulate flippase function and activity of the nuclear Pdr1 transcription factor. Together, these data argue that the interaction of the ABC transporters Pdr5 and Yor1 with the Lem3-dependent flippases regulates permeability of AbA via control of plasma membrane protein function as seen for the high-affinity tryptophan permease Tat2.
Effects of proton pump inhibitors and histamine-2 receptor antagonists on response to fidaxomicin or vancomycin in patients withClostridium difficile-associated diarrhoea
Authors: Weiss Karl , Louie Thomas , Miller Mark A , Mullane Kathleen , Crook Derrick W , Gorbach Sherwood L 
Published: March 2015

ObjectiveIt has been established that use of proton pump inhibitors (PPIs) is associated with an increased risk of acquiringClostridium difficile-associated diarrhoea (CDAD). However, it is not known whether the use of PPIs or histamine-2 receptor antagonists (H2RAs) concurrently with CDAD-targeted antibiotic treatment affects clinical response or recurrence rates.DesignIn two phase 3 trials, patients with toxin-positive CDAD were randomised to receive fidaxomicin 200 mg twice daily or vancomycin 125 mg four times daily for 10 days. Only inpatients with CDAD (due to complete medication record availability) were included in this post hoc analysis: 701 patients, of whom 446 (64%) used PPIs or H2RAs during study drug treatment or follow-up. Baseline factors that were statistically significant in univariate analyses were analysed in multivariate analyses of effects on clinical response and recurrence.ResultsMultivariate analysis showed that leukocytosis, elevated creatinine and hypoalbuminemia, but not PPI or H2RA use, were significant factors associated with poor clinical responses. Treatment group was the single significant predictor of recurrence; the probability of recurrence after fidaxomicin therapy was half that following vancomycin therapy.ConclusionsAcid-suppressing drugs, used by nearly two-thirds of inpatients with CDAD, did not worsen clinical response or recurrence when used concurrently with fidaxomicin or vancomycin. Therefore, development of CDAD does not require discontinuation of anti-acid treatment in patients who have an indication for continuing PPI or H2RA therapy, such as gastro-oesophageal reflux disease and risk of gastrointestinal bleed.
Efficacy of enrofloxacin for the treatment of acute clinical mastitis caused byEscherichia coliin dairy cows
Authors: Persson Y. , Katholm J. , Landin H. , Mörk M. J. 
Published: February 2015

Evidence for the efficacy of antimicrobial treatments inEscherichia colimastitis is limited. The aim of this double‐blinded field trial was to investigate the efficacy of enrofloxacin compared with placebo, with a special focus on survival, in dairy cows with acute clinical mastitis caused byE. coli. Dairy cows (n=116) with acute clinical mastitis were included in the study. A clinical examination was performed and a milk sample from the affected udder quarter was collected for investigation of somatic cell count (SCC) and bacteriology on the first day of treatment (day 0) and at day 3 (clinical examination only), day 22 and day 28. Data regarding culled cows, SCC and daily milk yield were retrieved from monthly milk recording each month until 180 days after treatment. All cows were treated with either enrofloxacin or placebo once a day for three days, starting at day 0. After culturing, 56 cows with confirmedE. colimastitis remained in the study. Nine (16 per cent) of them died within the first week. Enrofloxacin‐treated cows had lower SCC compared with placebo‐treated cows at first monthly milk recordings after being treated for mastitis. Treatment with enrofloxacin did not result in a higher probability of survival compared with placebo.
In vitro assessment of aiming bias in the frontal plane during orthopaedic drilling procedures
Authors: Sparrow T. , Heller J. , Farrell M. 
Published: February 2015

Drilling trials were performed using drilling boards incorporating pairs of 22 mm polyethylene tubes mounted horizontally. The tubes were premarked with 20, 0.5 mm deep notches along the centre of their upper surface representing the starting point for each drilling trial. Volunteers were instructed to drill 20 straight holes across the tube until they penetrated both walls. Kirschner wires were inserted through each of the drill holes until they made indentations into the base board. Deviation of each mark from mid‐line was measured using digital callipers. The measured values were used to calculate deviation angles to the left (negative values) or right (positive values). Trials were performed with the drill and guide held in the surgeon's line‐of‐sight (LOS) and with 300 mm offset (OFF). A systematic error (aiming bias) was identified in all individuals. Overall, left‐hander's drilling action was skewed to the left and right‐hander's drilling action was skewed to the right. Using LOS technique, mean overall bias was 2.3° (range 0°–7.7°) to the left for left‐handers and 1.5o (range 0.3°–3.1°) to the right for right‐handers. Surprisingly, aiming bias was greater for LOS than for OFF, although the difference for this comparison was not statistically significant.