bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-voltage, large-strain soft electrothermal actuators based on laser-reduced graphene oxide/Ag particle composites
Authors: Wang Qian , Li Yu-Tao , Zhang Tian-Yu , Wang Dan-Yang , Tian Ye , Yan Jun-Chao , Tian He , Yang Yi , Yang Fan , Ren Tian-Ling
Published: March 2018

In this paper, low-voltage, large-strain flexible electrothermal actuators (ETAs) based on laser-reduced graphene oxide (LRGO)/Ag particle composites were fabricated in a simple and cost-efficient process. By adding Ag particles to the LRGO, the sheet resistance decreased effectively. Under a driving voltage of 28 V, the actuator obtained a bending angle of 192° within 6 s. Besides, the bending deformation could be precisely controlled by the driving voltage ranging from 10° to 192°. Finally, a gripper composed of two actuators was demonstrated to manipulate a piece of polydimethylsiloxane block. With the advantages of low-voltage, fast-response, and easy-to-manufacture, the graphene based ETAs have a promising application in soft robotics and soft machines.
Dzyaloshinskii–Moriya interaction in Pt/Co/Ir and Pt/Co/Ru multilayer films
Authors: Khadka Durga , Karayev Sabit , Huang S. X.
Published: March 2018

The interfacial Dzyaloshinskii–Moriya interaction (iDMI) in asymmetric magnetic multilayer films has displayed increasingly important roles in the modification of domain walls, stabilization of Skyrmions, and realization of new topological spin textures such as magnetic radial vortices. Unlike magnetization and magnetic anisotropy which can be readily measured, iDMI is difficult to measure. In this work, we measured the iDMI in Pt/Co/Ir and Pt/Co/Ru multilayer films by exploring the spin-orbit torque induced effective field under an in-plane bias magnetic field. Skyrmions have been reported to exist in Pt/Co/Ir multilayers. We found that Pt/Co/Ru multilayers have a similar magnitude of the iDMI for Pt/Co/Ir multilayers, suggesting that Pt/Co/Ru is a good candidate to host Skyrmions.
Magnetic phase dependence of the anomalous Hall effect in Mn3Sn single crystals
Authors: Sung N. H. , Ronning F. , Thompson J. D. , Bauer E. D.
Published: March 2018

Thermodynamic and transport properties are reported on single crystals of the hexagonal antiferromagnet Mn3Sn grown by the Sn flux technique. Magnetization measurements reveal two magnetic phase transitions at T1 = 275 K and T2 = 200 K, below the antiferromagnetic phase transition at TN ≈ 420 K. The Hall conductivity in zero magnetic field is suppressed dramatically from 4.7 Ω−1 cm−1 to near zero below T1, coincident with the vanishing of the weak ferromagnetic moment. This illustrates that the large anomalous Hall effect arising from the Berry curvature can be switched on and off by a subtle change in the symmetry of the magnetic structure near room temperature.
Plasma flow around and charge distribution of a dust cluster in a rf discharge
Authors: Schleede J. , Lewerentz L. , Bronold F. X. , Schneider R. , Fehske H.
Published: March 2018

We employ a particle-in-cell Monte Carlo collision/particle-particle particle-mesh simulation to study the plasma flow around and the charge distribution of a three-dimensional dust cluster in the sheath of a low-pressure rf argon discharge. The geometry of the cluster and its position in the sheath are fixed to the experimental values, prohibiting a mechanical response of the cluster. Electrically, however, the cluster and the plasma environment, mimicking also the experimental situation, are coupled self-consistently. We find a broad distribution of the charges collected by the grains. The ion flux shows on the scale of the Debye length strong focusing and shadowing inside and outside the cluster due to the attraction of the ions to the negatively charged grains, whereas the electron flux is characterized on this scale only by a weak spatial modulation of its magnitude depending on the rf phase. On the scale of the individual dust potentials, however, the electron flux deviates in the vicinity of the cluster strongly from the laminar flow associated with the plasma sheath. It develops convection patterns to compensate for the depletion of electrons inside the dust cluster.
Unexpected metal-insulator transition in thick Ca1-xSrxVO3 film on SrTiO3 (100) single crystal
Authors: Takayanagi Makoto , Tsuchiya Takashi , Namiki Wataru , Ueda Shigenori , Minohara Makoto , Horiba Koji , Kumigashira Hiroshi , Terabe Kazuya , Higuchi Tohru
Published: March 2018

Epitaxial Ca1-xSrxVO3 (0 ≦ x ≦ 1) thin films were grown on (100)-oriented SrTiO3 substrates by using the pulsed laser deposition technique. In contrast to the previous report that metal-insulator transition (MIT) in Ca1-xSrxVO3 (CSVO) was achieved only for extremely thin films (several nm thick), MIT was observed at 39, 72, and 113 K for films with a thickness of 50 nm. The electronic structure was investigated by hard and soft X-ray photoemission spectroscopy (HX-PES and SX-PES). The difference between these PES results was significant due to the variation in an escape depth of photoelectrons of PES. While HX-PES showed that the V 2p3/2 spectra consisted of four peaks (V5+, V4+, V3+, and V2+/1+), SX-PES showed only three peaks (V5+, V4+, and V3+). This difference can be caused by a strain from the substrate, which leads to the chemical disorder (V5+, V4+, V3+, and V2+/1+). The thin film near the substrate is affected by the strain. The positive magnetoresistance is attributed to the effect of electron-electron interactions in the disorder system. Therefore, the emergence of MIT can be explained by the electron-electron interactions from the chemical disorder due to the strain.
AC-dielectrophoretic force assisted fabrication of conducting quantum dot aggregates in the electrical breakdown-induced CNT nanogap
Authors: Shim Hyung Cheoul , Choi Hyekyoung , Jeong Sohee
Published: March 2018

In this paper, we fabricated quantum dot (QD) aggregates at desired locations using dielectrophoretic (DEP) forces induced in the carbon nanotube (CNT) nanogap created by Joule heating-induced electrical breakdown. Nanogaps with a size of at least 20–30 nm can be effectively fabricated in the ambient condition, and fabrication yield can be monitored through in-situ electrical signal without post morphological analysis. The geometry of CNT electrodes with high aspect ratio as well as the gap size of the electrodes to a few tens of nanometers scale enabled the derivation of sufficiently high DEP forces that facilitate the trapping of QD in the CNT nanogap. Above all, we were able to fabricate a conducting crack-free QD aggregates by exchanging the ligands on the surface of the QDs in the presence of a DEP force and this approach showed the possibility of being applied as a QD based optoelectronic devices.
Chemotactic behavior of spermatozoa captured using a microfluidic chip
Authors: Bhagwat Shweta , Sontakke Shraddha , K. Deekshith , Parte Priyanka , Jadhav Sameer
Published: March 2018

Chemotaxis, as a mechanism for sperm guidance in vivo, is an enigma which has been difficult to demonstrate. To address this issue, various devices have been designed to study sperm chemotaxis in vitro. Limitations of traditional chemotaxis devices were related to the inability to maintain a stable concentration gradient as well as track single sperm over long times. Microfluidics technology, which provides superior control over fluid flow, has been recently used to generate stable concentration gradients for investigating the chemotactic behavior of several cell types including spermatozoa. However, the chemotactic behavior of sperm has not been unequivocally demonstrated even in these studies due to the inability to distinguish it from rheotaxis, thermotaxis, and chemokinesis. For instance, the presence of fluid flow in the microchannels not only destabilizes the concentration gradient but also elicits a rheotactic response from sperm. In this work, we have designed a microfluidic device which can be used to establish both, a uniform concentration and a uniform concentration gradient in a stationary fluid. By facilitating measurement of sperm response in ascending, descending ,and uniform chemoattractant concentration, the assay could isolate sperm chemotactic response from rheotaxis and chemokinesis. The device was validated using acetylcholine, a known chemoattractant and further tested with rat oviductal fluid from the estrus phase.
Atomically engineered epitaxial anatase TiO2 metal-semiconductor field-effect transistors
Authors: Kim Brian S. Y. , Minohara Makoto , Hikita Yasuyuki , Bell Christopher , Hwang Harold Y.
Published: March 2018

Anatase TiO2 is a promising material for a vast array of electronic, energy, and environmental applications, including photocatalysis, photovoltaics, and sensors. A key requirement for these applications is the ability to modulate its electrical properties without dominant dopant scattering and while maintaining high carrier mobility. Here, we demonstrate the room temperature field-effect modulation of the conducting epitaxial interface between anatase TiO2 and LaAlO3 (001), which arises for LaO-terminated LaAlO3, while the AlO2-terminated interface is insulating. This approach, together with the metal-semiconductor field-effect transistor geometry, naturally bypasses the gate/channel interface traps, resulting in a high field-effect mobility μFE of 3.14 cm2 (V s)−1 approaching 98% of the corresponding Hall mobility μHall. Accordingly, the channel conductivity is modulated over 6 orders of magnitude over a gate voltage range of ∼4 V.
Towards rational design of metal-organic framework-based drug delivery systems
Authors: Simagina Anna A. , Polynski Mikhail V. , Vinogradov Alexander V. , Pidko Evgeny A.
Published: March 2018

Metal-organic frameworks comprise a class of crystalline porous coordination polymers with unique chemical and physical properties. On the one hand, due to high specific surface area, biocompatibility and stability in biological media, framework materials are ideal candidates for the development of new dosage forms, in particular, for drug delivery systems. On the other hand, the modular structure of frameworks provides an opportunity for computational screening and predictive calculations. This opens new prospects for the design of modern functional materials. The computational screening and simulation of adsorption – desorption processes play a key role in the development of drug delivery systems, as they provide data that are difficult to obtain solely from experiments. These data can greatly assist in the development of drug delivery systems. The first part of the review gives a brief overview of the metal-organic frameworks which have already proved to be potential drug carriers as well as frameworks which are currently being extensively studied and gain attention in this area. The second part addresses the concept of rational design and computer-aided design of such systems.

The bibliography includes 216 references.
Carcass and meat quality of young Cika and Simmental bulls finished under similar conditions
Authors: Simčič Mojca , Čepon Marko , Žgur Silvester
Published: March 2018

Twenty indigenous Cika and 20 young Simmental bulls (slaughtered at 560–718 days) were finished on two diets (extensive vs semi-intensive). When fed similar rations, Cika bulls at a ‘suitable’ finished level, had a significantly higher dressing percentage (+2.5%), more total fat (+13.7%), a lower percentage of tendons (–22.7%) and bones (–7.7%), a higher lean meat to bones ratio (+8.1%) and a greater percentage of intramuscular fat (+45.9%) than the Simmental bulls. Their meat also had a significantly lower pH (–4.0%), higher redness (+13.74%), yellowness (+15.0%) and drip loss (after 2 days, +28.3%) and a more intense flavour (+6.1%). Cika fat contained higher proportions of saturated fatty acids (+6.86%) and less polyunsaturated fatty acids (–30.8%) than Simmental fat. However, it appears that the main difference between these two breeds were the slower growth rate of the Cika and their lower weight but greater age when a finished state was reached relative to the Simmental.
Analysis of the spatial variation in the abundance of lesser rheas using density surface models
Authors: Antún Milagros , Baldi Ricardo , Bandieri Lucas M. , Agostino Romina L. D'
Published: March 2018

Context
The study of the spatial variation in abundance of wild populations and the identification of factors explaining the observed patterns are key both to understand aspects of basic ecology and the effects of human activities. This is usually difficult to evaluate for low-density and widely distributed species, such as the lesser rhea (Rhea pennata pennata), an endemic bird from South America. Recent advances in spatial modelling such as the density surface models (DSM) combine distance-sampling procedures with modelling techniques to produce maps of spatial variation in abundance, and its relationship with predictive variables.

Aims
We aimed to analyse the spatial distribution and abundance of lesser rhea, and the variables that affect its abundance in Península Valdés (PV) Argentine Patagonia.

Methods
We conducted 338.4 km of ground surveys of lesser rheas in PV during the end of the Austral summer of 2015. Spatial models were constructed using DSM. Ecological and human-related variables were included in the models to account for variation in the abundance of animals at 4-km2 spatial resolution.

Key results
We estimated an overall density of 0.44 birds km–2 (CV = 32%) for the prediction area of 3320 km2. High values of normalised difference vegetation index, a correlate of plant productivity, were associated with increased numbers of lesser rheas. The location of ranch buildings, indicators of human presence, had a strong negative effect on lesser rheas, although their abundance increased at high sheep stocking rates.

Conclusions
As reported by previous studies in different sites, the abundance of lesser rheas in our study area was low. The use of DSM allowed a detailed examination of the spatial variation, as well as the variables involved and the uncertainty of the prediction.

Implications
The use of DSM techniques can be a useful tool for conservation planning and monitoring. Spatial, high-resolution data combined with knowledge on the factors affecting the number of animals are crucial to target specific conservation actions and monitor their results, and should allow government agencies to make better decisions concerning conservation-oriented management.
An Electronic Intervention to Improve Safety for Pain Patients Co-Prescribed Chronic Opioids and Benzodiazepines
Authors: Zaman Tauheed , Rife Tessa L. , Batki Steven L. , Pennington David L.
Published: March 2018

Background: Co-prescribing opioids and benzodiazepines increases overdose risk. A paucity of literature exists evaluating strategies to improve safety of co-prescribing. This study evaluated an electronic intervention to improve safety for patients co-prescribed chronic opioids for pain and benzodiazepines at 3 and 6 months. Methods: A prospective cohort study was conducted from December 2015 through May 2016 at San Francisco Veterans Affairs Health Care System. A clinical dashboard identified 145 eligible patients prescribed chronic opioids and benzodiazepines. Individualized taper and safety recommendations were communicated to prescribers via electronic medical record progress note and encrypted e-mail at baseline. Primary outcome was number of patients co-prescribed chronic opioids and benzodiazepines. Secondary outcomes included daily dose of opioids and benzodiazepines and number prescribed ≥100 mg morphine equivalent daily dose. Safety outcomes included number with opioid overdose education and naloxone distribution, annual urine drug screening, annual prescription drug monitoring program review, and signed opioid informed consent. Linear mixed models and generalized estimating equations were used to examine within-group change in outcomes between baseline and 3 and 6 months. Results: Among the 145 patients, mean (standard deviation) age was 62 (11) years and 91.7% (133/145) were male. Number co-prescribed significantly decreased from 145/145 (100%) at baseline to 93/139 (67%) at 6-month follow-up (odds ratio [OR] = 0.53, 95% confidence interval [CI]: 0.34–0.81, P = .003). Mean opioid and benzodiazepine doses significantly decreased from 84.61 to 65.63 mg (95% CI: 8.32–27.86, P < .001) and from 16.10 to 13.45 mg (95% CI: 1.6–3.9, P < .001), respectively, from baseline to 6-month follow-up. Patients prescribed ≥100 mg morphine equivalent daily dose significantly decreased from 39/145 (26.8%) at baseline to 26/139 (18.7%) at end of study (OR = 0.59, 95% CI: 0.44–0.78, P < .001), and patients with opioid overdose education and naloxone distribution significantly increased from 3/145 (2.1%) at baseline to 46/139 (33.1%; OR = 23.4, 95% CI: 7.61–71.99, P < .001) by the end of study. Number of patients with annual urine drug screening tended to increase from 123/145 (84.8%) at baseline to 132/145 (91.4%) by the end of study (OR = 1.89, 95% CI: 0.95–3.76, P = .07), and there were no significant changes across time in numbers of patients with annual prescription drug monitoring program review or signed opioid informed consent. Conclusions: Electronic interventions may provide an effective strategy to improve safety for patients co-prescribed chronic opioids for pain and benzodiazepines.
Factors Associated with Contingency Management Adoption among Opioid Treatment Providers Receiving a Comprehensive Implementation Strategy
Authors: Becker Sara J. , Kelly Lourah M. , Kang Augustine W. , Escobar Katherine I. , Squires Daniel D.
Published: March 2018

Background: Contingency management (CM) is an evidence-based behavioral intervention for opioid use disorders (OUDs); however, CM adoption in OUD treatment centers remains low due to barriers at patient, provider, and organizational levels. In a recent trial, OUD treatment providers who received the Science to Service Laboratory (SSL), a multilevel implementation strategy developed by a federally funded addiction training center, had significantly greater odds of CM adoption than providers who received training as usual. This study examined whether CM adoption frequency varied as a function of provider sociodemographic characteristics (i.e., age, race/ethnicity, licensure) and perceived barriers to adoption (i.e., patient-, provider-, organization-level) among providers receiving the SSL in an opioid treatment program. Methods: Thirty-nine providers (67% female, 77% non-Hispanic white, 72% with specialty licensure, Mage = 42 [SD = 11.46]) received the SSL, which consisted of didactic training, performance feedback, specialized training of internal change champions, and external coaching. Providers completed a comprehensive baseline assessment and reported on their adoption of CM biweekly for 52 weeks. Results: Providers reported using CM an average of nine 2-week intervals (SD = 6.35). Hierarchical multiple regression found that providers identifying as younger, non-Hispanic white, and without addiction-related licensure all had higher levels of CM adoption frequency. Higher perceived patient-level barriers predicted lower levels of CM adoption frequency, whereas provider- and organization-level barriers were not significant predictors. Conclusions: The significant effect of age on CM adoption frequency was consistent with prior research on predictors of evidence-based practice adoption, whereas the effect of licensure was counter to prior research. The finding that CM adoption frequency was lower among racially/ethnically diverse providers was not expected and suggests that the SSL may require adaptation to meet the needs of diverse opioid treatment providers. Entities using the SSL may also wish to incorporate a more explicit focus on patient-level barriers.
A Novel Approach to Treating Adolescents with Opioid use Disorder in Pediatric Primary Care
Authors: Levy Sharon , Mountain-Ray Shannon , Reynolds Jason , Mendes Steven J. , Bromberg Jonas
Published: March 2018

Background

Medication treatment for opioid use disorder is effective, and recommended for adolescents, though very few adolescents with opioid use disorder ever receive medications. Reasons include lack of trained medication prescribers for this age group and difficulty in identifying adolescents with substance use disorders. This manuscript examines a novel implementation model of identifying and providing treatment for substance use disorders, including opioid use disorder, in a pediatric primary care practice.

Methods

Patients presenting to a selected primary care pediatrics practice for any reason between March 9, 2017 and July 24, 2017 that were identified by screening, self-report or other clinical information to have a substance use problem were referred to an integrated clinical social worker for treatment. We recorded the number of patients that were referred, number of visits completed and SUD and mental health diagnoses.

Results

In the first 4 months of this program, 683 patients aged 12–22 completed a health maintenance appointment; 20 were referred for substance use disorder treatment and 13 completed at least one substance use disorder treatment visit with the integrated clinical social worker. The mean number of visits completed was 5.3. Three patients with opioid use disorders were identified and 2 were induced on buprenorphine.

Conclusions

Our model for treatment of substance use disorders, including opioid use disorders, was feasible and acceptable in a pediatric primary care practice. Broadly implemented, such a model could substantially increase access to substance use disorder treatment for adolescents and young adults.
Breaking and making curriculum from inside ‘policy storms’ in an Australian pre‐service teacher education course
Authors: Lambert Karen , O'Connor Justen
Published: March 2018

How teacher educators respond as policy actors from inside spaces where multiple policies and discourses collide provides insights into the ways in which policy plays out in educational contexts. By engaging and working within the uncertain space of our own contextual ‘policy storm’ we provide a narrative of enactment highlighting the roles and actions of policy actors simultaneously constrained and inspired by policy. We use the policy actor framework [Ball, S.J., Maguire, M., Braun, A., & Hoskins, K. (2011a). Policy actors: Doing policy work in schools, Discourse: Studies in the Cultural Politics of Education, 32(4), 625‐639] to unpack policy meaning‐making within university and faculty climates, teacher education, and curriculum reform in Health and Physical Education (HPE) in Australia. This paper has three tasks. Firstly, we set‐up the conditions of uncertainty and possibility as a ‘policy storm’ and place where four disparate policies converged. Secondly, we provide an empirical and theoretical account of policy interpretation and enactment from the actors perspective. Finally, we test the policy actor framework to determine if it adequately describes our insider policy work. In moving beyond reductionist policy narratives we provide policy possibilities that illustrate enactment, are innovative, and explore the productive potential inside policy reform.
Lgr5+ intestinal stem cells reside in an unlicensed G1 phase
Authors: Carroll Thomas D. , Newton Ian P. , Chen Yu , Blow J. Julian , Näthke Inke
Published: March 2018

During late mitosis and the early G1 phase, the origins of replication are licensed by binding to double hexamers of MCM2–7. In this study, we investigated how licensing and proliferative commitment are coupled in the epithelium of the small intestine. We developed a method for identifying cells in intact tissue containing DNA-bound MCM2–7. Interphase cells above the transit-amplifying compartment had no DNA-bound MCM2–7, but still expressed the MCM2–7 protein, suggesting that licensing is inhibited immediately upon differentiation. Strikingly, we found most proliferative Lgr5+ stem cells are in an unlicensed state. This suggests that the elongated cell–cycle of intestinal stem cells is caused by an increased G1 length, characterized by dormant periods with unlicensed origins. Significantly, the unlicensed state is lost in Apc-mutant epithelium, which lacks a functional restriction point, causing licensing immediately upon G1 entry. We propose that the unlicensed G1 phase of intestinal stem cells creates a temporal window when proliferative fate decisions can be made.
Risk Factors for Orthostatic Hypotension: Differences Between Elderly Men and Women
Authors: Méndez Andrea S , Melgarejo Jesús D , Mena Luis J , Chávez Carlos A , González Alicex C , Boggia José , Terwilliger Joseph D , Lee Joseph H , Maestre Gladys E
Published: March 2018

BACKGROUND

Orthostatic hypotension (OH) occurs when mechanisms regulating blood pressure (BP) levels after standing-up are altered. It is unclear how prevalence and risk factors for OH are different between sexes. We aimed to investigate sex differences in prevalence and risk factors for OH elderly individuals.

METHODS

We included 882 participants from Maracaibo Aging Study. OH was a sustained reduction of ≥20 mm Hg in systolic BP, ≥10 mm Hg in diastolic BP, or both, after 3 minutes of changing positions from supine to standing. Multivariable logistic regression models were used to examine the relationships among risk factors for OH in men and women considering interaction sex-term and stratified by sex.

RESULTS

The mean age was 66.7 ± 8.5 years, being similar by sex. Women and men 55–74 years had similar prevalence of OH+ (18.5% vs. 20.9%, respectively). After 75 years, the proportion of women with OH+ was lower than men (11% vs. 30%, respectively). Hypertension, specifically systolic BP ≥140 mm Hg, and high pulse pressure (PP) were related with OH+ accounted by interaction sex-term, while diastolic BP ≥90 mm Hg, antihypertensive treatment, body mass index (BMI), diabetes mellitus and age were not. Systolic BP ≥140 mm Hg increases the risk of OH only among women, while BMI showed an inverse association in both sexes.

CONCLUSIONS

Although the prevalence of OH is similar in both sexes, there are different risk factors associated by sex. Systolic BP ≥140 mm Hg was associated with increased risk of OH only with women while BMI was a protective factor for OH in men and women.
A stroboscopic averaging algorithm for highly oscillatory delay problems
Authors: Sanz-Serna J M , Zhu Beibei
Published: March 2018

We propose and analyse a heterogeneous multiscale method for the efficient integration of constant-delay differential equations subject to fast periodic forcing. The stroboscopic averaging method suggested here may provide approximations with $\mathscr{O}\big (H^{2}+1/\varOmega ^{2}\big )$ errors with a computational effort that grows like $H^{-1}$ (the inverse of the step size), uniformly in the forcing frequency $\varOmega $.
Universal Gröbner Bases and Cartwright–Sturmfels Ideals
Authors: Conca A , De Negri E , Gorla E
Published: March 2018

The main theoretical contribution of the paper is the description of two classes of multigraded ideals named after Cartwright and Sturmfels and the study of their surprising properties. Among other things we prove that these classes of ideals have very special multigraded generic initial ideals and are closed under several operations including arbitrary multigraded hyperplane sections. As a main application we describe the universal Gröbner basis of the ideal of maximal minors and the ideal of 2-minors of a multigraded matrix of linear forms generalizing earlier results of various authors including Bernstein, Sturmfels, Zelevinsky, and Boocher.
Equality Cases in Viterbo’s Conjecture and Isoperimetric Billiard Inequalities
Authors: Balitskiy Alexey
Published: March 2018

We apply the billiard technique to deduce some results on Viterbo’s conjectured inequality between the volume of a convex body and its symplectic capacity. We show that the product of a permutohedron and a simplex (properly related to each other) delivers equality in Viterbo’s conjecture. Using this result as well as previously known equality cases, we prove some special cases of Viterbo’s conjecture and interpret them as isoperimetric-like inequalities for billiard trajectories.
Enteropathogen Detection in Children with Diarrhea and/or Vomiting: A Cohort Study Comparing Rectal Flocked Swabs and Stool Specimens
Authors: Freedman Stephen , Nettel-Aguirre Alberto , Xie Jianling , Lee Bonita , Chui Linda , Pang Xiao-Li , Zhuo Ran , Parsons Brendon , Dickinson James , Vanderkooi Otto G , Ali Samina , Osterreicher Lara , Lowerison Karen , Tarr Phillip ,   Alberta Pediatric EnTeric Infection TEam (APPETITE)
Published: March 2018

Background

Diarrheal stool samples are currently preferred for enteropathogen detection, but they are inconvenient to collect if they are not immediately available, leading to suboptimal return rates and delayed or missed diagnostic opportunities. We sought to compare the enteropathogen yields of rectal swabs and stool specimens in an outpatient cohort of children with diarrhea and/or vomiting.

Methods

Eligible children were < 18 years of age, with ≥3 episodes of vomiting or diarrhea in 24 hours and <7 days of symptoms. After excluding those enrolled within the prior fortnight, unable to follow-up, having psychiatric illness, neutropenia, or requiring emergent care, we attempted to collect rectal swabs and stool from all participants. Specimens were subjected to testing with the Luminex xTAG Gastrointestinal Pathogen Panel, an in-house 5-virus panel and bacterial culture. Primary outcomes were comparative (submitted paired specimens only) and overall (all specimens, unsubmitted specimens analyzed as negative) yields. We used McNemar’s test to conduct pathogen-specific analyses, and generalized estimating equations to perform global (i.e., any) pathogen analyses with adjustments made for the presence of diarrhea, location, and their interactions with specimen type.

Results

Of the 1,519 subjects enrolled, 1,147 (75·5%) and 1,514 (99·7%) provided stool and swab specimens, respectively. The proportions of specimens positive for any pathogen were 75.9% (871/1,147) and 67.6% (1,024/1,514); P < 0.0001. Comparative yield adjusted OR in stool relative to swabs were 1.24 (95% CI: 1.11, 1.38) and 1.76 (95% CI: 1.47, 2.11) in children with and without diarrhea at presentation, respectively. Overall concordance analysis yielded a kappa of 0.76 (95% CI: 0.71, 0.80). Paired positive viral specimens had lower median cycle threshold values (i.e., higher viral loads; P < 0·0001) in SSs compared with swabs for all viruses. In overall yield analysis, the proportions positive for a pathogen were 57.3% and 67.4 for stool and rectal swabs, respectively; unadjusted OR: 0.65 (95% CI: 0.59, 0.72) for stool relative to swab.

Conclusion

Rectal swabs should be performed when enteropathogen identification, and/or rapid detection, is needed, molecular diagnostic technology available, and stool not immediately available.

Disclosures

All authors: No reported disclosures.
Predictive Clinical Rule for Readmissions in OPAT. Improving in Security
Authors: Bengoetxea Itsaso , Onaindia Miren J , Apezetxea Antonio , Gomez Montserrat , Goyeneche Muskilda , Fernandez Magdalena , Vazquez Begoña , Berroete Miriam , Olarreaga Itziar , Quintana Jose M , Aguirre Urko ,   HOSPITAL AT HOME BASQUE SOCIETY
Published: March 2018

Background

Outpatient Parenteral Antibiotic Therapy (OPAT) is a safe, effective and beneficial practice but studies report 10–20% of readmissions rate. The risk factors for readmissions in OPAT have been investigated, although there are no clinical tools that allow us to predict these situations. The main goal of this study is to develop and validate a predictive model for readmission in OPAT patients.

Methods

Prospective study was conducted during 1 year (10/2012–09/2013), 1488 patients with OPAT were recruited at 8 units of Hospital at Home in Spain. Potential risk factors related to patient demographics, lead-time factors, clinical and microbiologic features were collected. We developed the prediction model in a derivation sample and after that, we validated this model in the validation sample. Sensitivity, specificity and area under the curve were obtained and the calibration capacity of the models were evaluated using the Hosmer-Lemeshow test (H-L).

Results

The mean age of patients was 63 years (range 11–102), 58.74% men and most common diagnoses were urinary tract infections (23%). Our readmission rate during OPAT episode at home was 8.67% and the 30-days readmissions were 12.29%. The 72% of the readmissions during OPAT episode was related to the infectious pathology and 27.90% to the the patient’s comorbidity.

The leading indicators for readmission were: gender, age, presence of caregivers, risk factor for infection, Charlsonand Barthel Index, microorganisme number, presence of multirresistent or micotic infection, venous access, antibiotic type and creatinine, proteine and leucocyte level at admissions. Finally, those factors included in the model were: antibiotic type (OR 3.93; IC 95% 1.90–8.11; P = 0.0002), presence of infection risk factor (OR 2.53; IC 95% 1.47–4.38; P = 0.001) and leucocytosis at admission (OR 2.21; IC 95% 1.32–3.71; P = 0.003). The AUC for the model was 0.72 (IC 95% 0.66–0.78) and the H-L value was 0.23. After the validation the AUC was 0.71 (IC 95% 0.64–0.78) and H-L value 0.9.

Conclusion

Patients at high risk of readmission during OPAT may be identified using predictive rules. This will allow us to implement measures that reduce the rate of readmissions and contribute to increase the safety of this therapy.

Disclosures

All authors: No reported disclosures.
High Genetic Variability of Norovirus Leads to Diagnostic Test Challenges
Authors: Pang Xiaoli , Zhuo Ran , Qiu Yuanyuan , Parsons Brendon , Lee Bonita , Chui Linda , Freedman Stephen ,   the Alberta Provincial Pediatric EnTeric Infection TEam (APPETITE)
Published: March 2018

Background

It is important to understand the diagnostic accuracy of syndromic multiplex panels such as the Luminex xTAG® Gastrointestinal Pathogen Panel (GPP) as they are increasingly employed as routine diagnostic tests in laboratories worldwide. Recent evaluations in our laboratory identified lower detection rates of norovirus genogroup II (NoV GII) using the GPP as compared with our lab-developed RT-qPCR Gastroenteritis Virus Panel (GVP). This study is to characterize the NoV strains in samples with discordant NoV GII test results between GPP and GVP and determine the sensitivity of the two assays for specific NoV GII genotypes.

Methods

We genotyped all NoV GII strains with discordant test result in stool samples or rectal swabs collected prospectively from a cohort of children with acute gastroenteritis between December 2014 and July 2016. The sensitivity of GVP and GPP for NoV GII were compared by analyzing GVP threshold cycle (Ct) and using ten-fold serial dilutions of positive samples of various NoV GII genotypes.

Results

All discordant samples (11%; 63/607) tested positive for NoV GII by GVP but negative by GPP. Thirty-five percent (22/63) were successfully genotyped; 64% (14/22) of those were NoV GII genotype 2 (GII.2). The median Ct value of concordant positive was lower than those with discordant results (19.8 vs.. 33.7 respectively; P < 0.0001). GVP was 10-fold and at least 10,000-fold more sensitive than GPP in detecting NoV GII.3 and GII.2, respectively, but has similar sensitivity for NoV GII.4. The GII.2 variants with discordant test results differed genetically from the concordant GII.2 variants.

Conclusion

GPP has suboptimal sensitivity to detect NoV GII.2 and its use may lead to an underestimation of NoV disease burden with some cases not being detected.

Disclosures

All authors: No reported disclosures.
Relationship Between Enteropathogen and Acute Gastroenteritis Disease Severity: A Prospective Cohort Study
Authors: Freedman Stephen , Xie Jianling , Nettel-Aguirre Alberto , Lee Bonita , Chui Linda , Pang Xiao-Li , Zhuo Ran , Parsons Brendon , Vanderkooi Otto G , Tarr Phillip , Ali Samina , Dickinson James A , Hagen Evan , Svenson Lawrence W , MacDonald Shannon E , Drews Steven J , Tellier Raymond , Graham Tim , Lavoie Martin , Macdonald Judy ,   Alberta Provincial Pediatric EnTeric Infection TEam (APPETITE)
Published: March 2018

Background

Little is known about the association between specific enteropathogens and disease severity in outpatient children with acute gastroenteritis. Recent advances in diagnostics enabling the rapid and simultaneous detection of common enteropathogens have become readily available. While such knowledge can be used to optimize therapy it also has the potential to predict disease severity. Such knowledge can aid clinical decision making, can clarify guidance and expectations provided to families, and can guide public health policy.

Methods

We conducted a prospective cohort study of children with acute gastroenteritis who were brought for emergency department care. The primary outcome measure was the 20-point Modified Vesikari Scale (MVS) score calculated from symptom onset until day14 of follow-up (total MVS score). Stool and/or rectal swab specimens were collected and analyzed for 18 unique pathogens by molecular diagnostic assays (in-house 5 virus panel, Luminex xTAG Gastrointestinal Pathogen Panel) and/or bacterial culture. An enteropathogen was deemed to be present if a candidate pathogen was identified in the rectal swab or stool specimens by any testing method. Binary logistic regression was performed to assess the association between pathogens (including all pathogens as present or not) and disease severity with the dependent variable being the total MVS score categorized as severe (11–20 points) vs.. non-severe (0–10 points).

Results

The mean total MVS score (SD) was 12.8 (3.2) and 73.0% (807/1102) of participants experienced severe disease. A pathogen was identified in 72.8% (802/1102) of study participants. Rotavirus, norovirus GII and adenovirus were identified in 26.6% (293/1102), 23.0% (253/1102) and 16.0% (176/1102) of participants respectively. After adjusting for other pathogens significant predictors of severe disease were: rotavirus (OR=8.0; 95% CI: 4.8, 13.2), Salmonella (OR=5.4; 95% CI: 1.2, 24.4), adenovirus (OR=2.1; 95% CI: 1.3, 3.3), and norovirus GII (OR=1.8; 95% CI: 1.3, 2.6). Clostridium difficile (OR=1.6; 95% CI: 0.96, 2.6) and Aeromonas (OR=0.97; 95% CI: 0.2, 4.7) were not significantly associated with severe disease.

Conclusion

In children with acute gastroenteritis, the enteropathogens associated with severe disease included rotavirus, Salmonella, adenovirus and norovirus GII.

Disclosures

All authors: No reported disclosures.
Mobilization of the Anterior Inferior Cerebellar Artery When Firmly Adherent to the Petrous Dura Mater—A Technical Nuance in Retromastoid Transmeatal Vestibular Schwannoma Surgery: 3-Dimensional Operative Video
Authors: Tatagiba Marcos S , Evangelista-Zamora Rocío , Lieber Stefan
Published: March 2018

The anterior inferior cerebellar artery (AICA) usually runs loosely within the cerebellopontine cistern; in rare cases, however, it is firmly adherent to the petrous dura mater.
1,2
Recognizing this variation is particularly important in vestibular schwannoma surgery via the retrosigmoid transmeatal approach to prevent the high morbidity associated with vascular injury. This video demonstrates a surgical technique to effectively mobilize the AICA when firmly adherent to the petrous dura mater. A 39-year-old man presented with a history of progressive right-sided hearing loss without facial weakness or other associated symptoms
3
. Magnetic resonance imaging (MRI) demonstrated an intracanalicular lesion, suggestive of vestibular schwannoma. During follow-up, audiometry confirmed a further slight deterioration of hearing and repeated MRI demonstrated tumor growth (T2 according to Hannover classification). Since the patient opted against radiosurgery, a retrosigmoid transmeatal approach under continuous intraoperative monitoring was performed in supine position. Following drainage of cerebrospinal fluid and exposure of the cerebellopontine cistern, the AICA was found to be firmly adherent to the petrous dura mater. Both structures were elevated conjointly and displaced medially for safe drilling of the inner auditory canal, sufficient exposure, and complete excision of the vestibular schwannoma. The patient had an excellent recovery, hearing and facial function were preserved, and no secondary neurological deficits noted.

The patient consented to publication of this anonymized video.
Endoscopic Resection of an Intraventricular Tumor With Second Window Indocyanine Green: 2-Dimensional Operative Video
Authors: Hitti Frederick L , Lee John Y K
Published: March 2018

A 26-year-old woman presented to our clinic with years of headaches and mental clouding. She had a nonfocal neurological examination including benign ophthalmological examination. Head computed tomography and brain magnetic resonance imaging (MRI) demonstrated asymmetry of the lateral ventricles due to a lesion arising from the foramen of Monro. At the top of our differential diagnosis were choroid plexus tumor and colloid cyst. We offered the patient treatment via an endoscopic approach. Here, we demonstrate the feasibility of using tumor-localizing dyes such as indocyanine green (ICG) in conjunction with endoscopes equipped with lasers to localize and treat intraventricular lesions. While ICG is FDA approved, the technique presented here is investigational and the dye is being used off-label. The laser-equipped endoscope is also being used off-label. To treat the ventricular asymmetry, we performed an endoscopic septostomy between the frontal horns of the lateral ventricles. For our tumor-localizing dye technique, we injected the patient with ICG 24 hours before the planned surgery. We were able to clearly visualize the lesion at the foramen of Monro as it was intensely fluorescent. The dye also appeared to localize to the presumably normal choroid plexus. We resected the lesion endoscopically and permanent pathology revealed that the lesion was a choroid plexus papilloma. The postoperative MRI showed improvement in her ventricular asymmetry and complete resection of the enhancing lesion at the foramen of Monro. The patient recovered well and was uneventfully discharged. She was seen in follow-up and has had improvement in her headaches.

Consent for surgery was obtained from the patient. Consent for publication of the operative video was also obtained from the patient.
Microvascular Decompression of Facial Nerve and Pexy of the Left Vertebral Artery for Left Hemifacial Spasm: 3-Dimensional Operative Video
Authors: Cheng Chun-Yu , Shetty Rakshith , Martinez Vicente , Sekhar Laligam N
Published: March 2018

A 73-yr-old man presented with intractable left hemifacial spasm of 4 yr duration. Brain magnetic resonance imaging showed significant compression of left facial nerve by the left vertebral artery (VA) and anterior inferior cerebellar artery (AICA).

The patient underwent a left retrosigmoid craniotomy and a microvascular decompression of the cranial nerve (CN) VII. Intraoperatively, we found that the distal AICA had a protracted subarcuate extradural course.
1
This was relieved by intra/extradural dissection. The left VA and the AICA loop were compressing the root exit zone of CN VII. The VA was mobilized, and pexy into the petrosal dura was done with 8-0 nylon sutures (Ethilon Nylon Suture, Ethicon Inc, a subsidiary of Johnson & Johnson, Somerville, New Jersey). Once this was done, the lateral spread disappeared.
2
The AICA loop was decompressed with 2 pieces of Teflon felt (Bard PTFE felt, Bard peripheral Vascular Inc, a subsidiary of CR Bard Inc, Temp, Arizona). After this, wave V of the brainstem auditory evoked potential (BAEP) disappeared completely, with no recovery despite the application of the nicardipine on the internal auditory artery (IAA). The IAA appeared to be stretched by the microvascular decompression. Arachnoidal dissection was done to release the CN VIII and an additional felt piece was placed to elevate the AICA loop; the BAEP recovered completely. The patient had a complete disappearance of the hemifacial spasm postoperatively, and hearing was unchanged.

This 3-D video shows the technical nuances of performing a vertebropexy, release of the AICA from its extradural subarcuate course, and the surgical maneuvers in the event of an unexpected change in neuromonitoring response. The suture technique of vertebropexy is preferred to a loop technique, to avoid kinking of the VA.
3

Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.
Anterior Cervical Foraminotomy: 2-Dimensional Operative Video
Authors: Tan Lee A , Riew K Daniel
Published: March 2018

We provide a step-by-step technique guide for performing anterior cervical foraminotomy in this video. An illustrative case was presented with detailed narration and a discussion of surgical nuances. Anterior cervical foraminotomy can be an effective treatment strategy for patients with unilateral cervical radiculopathy without the need for cervical spine fusion. Spine surgeons should be familiar with technique and use it as a motion-preserving surgical option in treating isolated cervical radiculopathy. There is no identifying information in this video. A patient consent was obtained for publishing of the material included in the video.
Application of precision medicine to the treatment of anaphylaxis
Authors: Labella Marina , Garcia-Neuer Marlene , Castells Mariana
Published: March 2018

Purpose of review

Recognize the presentation of anaphylaxis for prompt management and treatment and to provide tools for the diagnosis of the underlying cause(s) and set up a long-term treatment to prevent recurrence of anaphylaxis.

Recent findings

The recent description of phenotypes provides new insight and understanding into the mechanisms and causes of anaphylaxis through a better understanding of endotypes and biomarkers for broad clinical use.

Anaphylaxis is the most severe hypersensitivity reaction and can lead to death. Epinephrine is the first-line treatment of anaphylaxis and it is life-saving. Patients with first-line therapy-induced anaphylaxis are candidates for desensitization to increase their quality of life and life expectancy. Desensitization is a breakthrough novel treatment for patients with anaphylaxis in need of first-line therapy, including chemotherapy, mAbs, aspirin and others. Ultrarush with venom immunotherapy should be considered in patients who present with life-threatening anaphylaxis after Hymenoptera sting with evidence of IgE-mediated mechanisms. Food desensitization is currently being expanded to provide increased safety to adults and children with food-induced anaphylaxis.