bluuebunny/crossref_metadata_2025 huggingface dataset:
Time‐division‐multiplex control scheme for voltage multiplier rectifiers
Authors: Liu Bin‐Han , Teng Jen‐Hao , Tsai Wei‐Lun
Published: March 2017

A voltage multiplier rectifier with a novel time‐division‐multiplexing (TDM) control scheme for high step‐up converters is proposed in this study. In the proposed TDM control scheme, two full‐wave voltage doubler rectifiers can be combined to realise a voltage quadrupler rectifier. The proposed voltage quadrupler rectifier can reduce transformer turn ratio and transformer size for high step‐up converters and also reduce voltage stress for the output capacitors and rectifier diodes. An N ‐times voltage rectifier can be straightforwardly produced by extending the concepts from the proposed TDM control scheme. A phase‐shift full‐bridge (PSFB) converter is adopted in the primary side of the proposed voltage quadrupler rectifier to construct a PSFB quadrupler converter. Experimental results for the PSFB quadrupler converter demonstrate the performance of the proposed TDM control scheme for voltage quadrupler rectifiers. An 8‐times voltage rectifier is simulated to determine the validity of extending the proposed TDM control scheme to realise an N ‐times voltage rectifier. Experimental and simulation results show that the proposed TDM control scheme has great potential to be used in high step‐up converters.
MMC with parallel‐connected MOSFETs as an alternative to wide bandgap converters for LVDC distribution networks
Authors: Zhong Yanni , Roscoe Nina M. , Holliday Derrick , Finney Stephen J.
Published: March 2017

Low‐voltage direct‐current (LVDC) networks offer improved conductor utilisation on existing infrastructure and reduced conversion stages, which can lead to a simpler and more efficient distribution network. However, LVDC networks must continue to support AC loads, requiring efficient, low‐distortion DC–AC converters. Additionally, increasing numbers of DC loads on the LVAC network require controlled, low‐distortion, unity power factor AC‐DC converters with large capacity, and bi‐directional capability. An AC–DC/DC–AC converter design is therefore proposed in this study to minimise conversion loss and maximise power quality. Comparative analysis is performed for a conventional IGBT two‐level converter, a SiC MOSFET two‐level converter, a Si MOSFET modular multi‐level converter (MMC) and a GaN HEMT MMC, in terms of power loss, reliability, fault tolerance, converter cost and heatsink size. The analysis indicates that the five‐level MMC with parallel‐connected Si MOSFETs is an efficient, cost‐effective converter for low‐voltage converter applications. MMC converters suffer negligible switching loss, which enables reduced device switching without loss penalty from increased harmonics and filtering. Optimal extent of parallel‐connection for MOSFETs in an MMC is investigated. Experimental results are presented to show the reduction in device stress and electromagnetic interference generating transients through the use of reduced switching and device parallel‐connection.
Fulfilling the promise of the materials genome initiative with high-throughput experimental methodologies
Authors: Green M. L. , Choi C. L. , Hattrick-Simpers J. R. , Joshi A. M. , Takeuchi I. , Barron S. C. , Campo E. , Chiang T. , Empedocles S. , Gregoire J. M. , Kusne A. G. , Martin J. , Mehta A. , Persson K. , Trautt Z. , Van Duren J. , Zakutayev A.
Published: March 2017

The Materials Genome Initiative, a national effort to introduce new materials into the market faster and at lower cost, has made significant progress in computational simulation and modeling of materials. To build on this progress, a large amount of experimental data for validating these models, and informing more sophisticated ones, will be required. High-throughput experimentation generates large volumes of experimental data using combinatorial materials synthesis and rapid measurement techniques, making it an ideal experimental complement to bring the Materials Genome Initiative vision to fruition. This paper reviews the state-of-the-art results, opportunities, and challenges in high-throughput experimentation for materials design. A major conclusion is that an effort to deploy a federated network of high-throughput experimental (synthesis and characterization) tools, which are integrated with a modern materials data infrastructure, is needed.
Electrostatic drift instability in a magnetotail configuration: The role of bouncing electrons
Authors: Fruit G. , Louarn P. , Tur A.
Published: March 2017

To understand the possible destabilization of two-dimensional current sheets, a kinetic model is proposed to describe the resonant interaction between electrostatic modes and trapped electrons that bounce within the sheet. This work follows the initial investigation by Tur, Louarn, and Yanovsky [Phys. Plasmas 17, 102905 (2010)] and Fruit, Louarn, and Tur [Phys. Plasmas 20, 022113 (2013)] that is revised and extended. Using a quasi-dipolar equilibrium state, the linearized gyro-kinetic Vlasov equation is solved for electrostatic fluctuations with a period of the order of the electron bounce period. Using an appropriated Fourier expansion of the particle motion along the magnetic field, the complete time integration of the non-local perturbed distribution functions is performed. The dispersion relation for electrostatic modes is then obtained through the quasineutrality condition. It is found that for a mildly stretched configuration (L∼8), strongly unstable electrostatic modes may develop in the current sheet with the growth rate of the order of a few seconds provided that the background density gradient responsible for the diamagnetic drift effects is sharp enough: typical length scale over one Earth radius or less. However, when this condition in the density gradient is not met, these electrostatic modes grow too slowly to be accountable for a rapid destabilization of the magnetic structure. This strong but finely tuned instability may offer opportunities to explain features in magnetospheric substorms.
Sensitivity estimation for stochastic models of biochemical reaction networks in the presence of extrinsic variability
Authors: Ruess Jakob , Koeppl Heinz , Zechner Christoph
Published: March 2017

Determining the sensitivity of certain system states or outputs to variations in parameters facilitates our understanding of the inner working of that system and is an essential design tool for the de novo construction of robust systems. In cell biology, the output of interest is often the response of a certain reaction network to some input (e.g., stressors or nutrients) and one aims to quantify the sensitivity of this response in the presence of parameter heterogeneity. We argue that for such applications, parametric sensitivities in their standard form do not paint a complete picture of a system’s robustness since one assumes that all cells in the population have the same parameters and are perturbed in the same way. Here, we consider stochastic reaction networks in which the parameters are randomly distributed over the population and propose a new sensitivity index that captures the robustness of system outputs upon changes in the characteristics of the parameter distribution, rather than the parameters themselves. Subsequently, we make use of Girsanov’s likelihood ratio method to construct a Monte Carlo estimator of this sensitivity index. However, it turns out that this estimator has an exceedingly large variance. To overcome this problem, we propose a novel estimation algorithm that makes use of a marginalization of the path distribution of stochastic reaction networks and leads to Rao-Blackwellized estimators with reduced variance.
Rapid isolation of blood plasma using a cascaded inertial microfluidic device
Authors: Robinson M. , Marks H. , Hinsdale T. , Maitland K. , Coté G.
Published: March 2017

Blood, saliva, mucus, sweat, sputum, and other biological fluids are often hindered in their ability to be used in point-of-care (POC) diagnostics because their assays require some form of off-site sample pre-preparation to effectively separate biomarkers from larger components such as cells. The rapid isolation, identification, and quantification of proteins and other small molecules circulating in the blood plasma from larger interfering molecules are therefore particularly important factors for optical blood diagnostic tests, in particular, when using optical approaches that incur spectroscopic interference from hemoglobin-rich red blood cells (RBCs). In this work, a sequential spiral polydimethylsiloxane (PDMS) microfluidic device for rapid (∼1 min) on-chip blood cell separation is presented. The chip utilizes Dean-force induced migration via two 5-loop Archimedean spirals in series. The chip was characterized in its ability to filter solutions containing fluorescent beads and silver nanoparticles and further using blood solutions doped with a fluorescent protein. Through these experiments, both cellular and small molecule behaviors in the chip were assessed. The results exhibit an average RBC separation efficiency of ∼99% at a rate of 5.2 × 106 cells per second while retaining 95% of plasma components. This chip is uniquely suited for integration within a larger point-of-care diagnostic system for the testing of blood plasma, and the use of multiple filtering spirals allows for the tuning of filtering steps, making this device and the underlying technique applicable for a wide range of separation applications.
Modeling and simulation of a residential microgrid supplied with PV/batteries in connected/disconnected modes—Case of Morocco
Authors: Tazi K. , Abbou F. M. , Bannour Chaka A. , Abdi F.
Published: March 2017

Micro-grids are small-scale grids, equipped with energy management and on-site energy generation. They offer low-cost power to consumers, and combined with green energy, they are a promising solution to build the future smart city. This paper discusses the different components of a micro-grid and their mathematical equations. The model is built in Matlab/Simulink and respects the distribution rules of the Moroccan grid code. The modeled residential group represents the power consumption of an average Moroccan household in the mountainous region of Ifrane. Two simulation scenarios were designed in order to validate the model. The first scenario tests the microgrid during normal operation, while the second scenario introduces a grid fault, requiring disconnection from the utility grid. Simulation results show that the model responds to the specified weather and system conditions as predicted.
Dry matter accumulation and partitioning of two taro (Colocasia Esculenta (L.) Schott) cultivars under Inceptisol soils in Samoa
Authors: Fa'amatuainu Walter , Amosa Falaniko
Published: March 2017

Taro (Colocasia esculenta) crop is widely grown throughout the humid tropics for its edible leaves, petioles and corms. In this research total dry matter (DM) accumulation and its partitioning between different plant parts were studied to determine their growth pattern over the plants’ life cycle (i.e. 35, 70, 105, 140 and 175 days after planting (DAP). An experiment with randomised complete block design (RCBD) having five treatments (DAP) and three replications (blocks) was setup for each of the two improved taro cultivars (Samoa 1 and Samoa 2). After harvest dry matter of each taro plant was estimated for its five parts: leaf blades, petioles, corms, roots and suckers. The data analysis showed that in both the cultivars the DM accumulation and its partitioning to different plant parts (i.e. the leaf blades (LDM), petioles (PDM), roots (RDM), corms (CDM) and suckers (SDM)) varied significantly (p
A Comparison of Size Structure, Age, and Growth of Red Snapper from Artificial and Natural Habitats in the Western Gulf of Mexico
Authors: Streich Matthew K. , Ajemian Matthew J. , Wetz Jennifer J. , Williams Jason A. , Shipley J. Brooke , Stunz Gregory W.
Published: March 2017

Red SnapperLutjanus campechanussupport economically important fisheries in the Gulf of Mexico (GOM) and have been classified as overfished since the first stock assessment was conducted in 1988. Although the stock is now showing signs of recovery, management could benefit from a better understanding of regional or even habitat‐level differences in stock demographics, as these dynamics ultimately determine overall stock productivity. From 2012 to 2014, we used a fishery‐independent vertical line survey to assess Red Snapper relative abundance, size and age structure, and growth parameters at standing oil and gas platforms, decommissioned platform artificial reefs, and natural banks in the western GOM. We captured 1,170 Red Snapper ranging from 275 to 855 mm TL. Vertical line CPUE data showed no differences among the three habitat types. Ages determined for 1,143 individuals ranged from 2 to 30 years; however, most (90%) were younger than age 8. Size and age frequencies revealed that natural banks supported a greater proportion of large and relatively old fish compared to standing platforms or artificial reefs, although this difference was heavily influenced by a single bank that had significantly larger and older Red Snapper than other sites. Mean age was not significantly different among habitat types. Among a suite of growth models fitted to size‐at‐age data, the logistic model provided the best fit and suggested that fish from artificial reefs reached larger sizes at age than fish from either standing platforms or natural banks. Our study provides the first estimates of habitat‐specific growth parameters for Red Snapper in the western GOM, and this information can benefit future stock assessments. This study also highlights the potential benefits of artificial reefs to Red Snapper and indicates that all habitats could contribute similarly to stock productivity on a per‐unit‐area basis.

Received December 21, 2016; accepted March 14, 2017 Published online May 26, 2017
Invited Commentary: A Landmark Study Launched in a Public Health
Maelstrom
Authors: Engels Eric A. , Rabkin Charles S. , Goedert James J.
Published: March 2017

The acquired immune deficiency syndrome (AIDS) epidemic was first recognized in 1981, and it quickly became a public health emergency. In a 1987 paper in the American Journal of Epidemiology (Am J Epidemiol. 1987;126(2): 310–318), Richard Kaslow et al. described the launch of the Multicenter AIDS Cohort Study (MACS), a cohort study of homosexual men in 4 US cities, the purpose of which was to better understand the natural history of AIDS and its determinants. The MACS enrolled participants through a range of community contacts. These efforts facilitated rapid recruitment, but given the targeted approaches, participants tended to comprise high-risk social networks. At baseline, 4%–26% of participants at the 4 sites reported having a sexual partner who had developed AIDS. Kaslow et al. also described baseline testing for the causative agent of AIDS, the human immunodeficiency virus (HIV). HIV seroprevalence was remarkably high, ranging from 11%–26% across age groups in Pittsburgh to 38%–53% in Los Angeles. The major turning point in the epidemic occurred in 1995–1996 when combination antiretroviral therapy was introduced, effectively blocking HIV replication and markedly reducing AIDS morbidity and mortality. The MACS cohort continues to be followed actively 3 decades after its launch and has proven to be an important resource for information on HIV infection and AIDS.
EUPAN enables pan-genome studies of a large number of eukaryotic genomes
Authors: Hu Zhiqiang , Sun Chen , Lu Kuang-chen , Chu Xixia , Zhao Yue , Lu Jinyuan , Shi Jianxin , Wei Chaochun
Published: March 2017

Pan-genome analyses are routinely carried out for bacteria to interpret the within-species gene presence/absence variations (PAVs). However, pan-genome analyses are rare for eukaryotes due to the large sizes and higher complexities of their genomes. Here we proposed EUPAN, a eukaryotic pan-genome analysis toolkit, enabling automatic large-scale eukaryotic pan-genome analyses and detection of gene PAVs at a relatively low sequencing depth. In the previous studies, we demonstrated the effectiveness and high accuracy of EUPAN in the pan-genome analysis of 453 rice genomes, in which we also revealed widespread gene PAVs among individual rice genomes. Moreover, EUPAN can be directly applied to the current re-sequencing projects primarily focusing on single nucleotide polymorphisms.

Availability and Implementation

EUPAN is implemented in Perl, R and C ++. It is supported under Linux and preferred for a computer cluster with LSF and SLURM job scheduling system. EUPAN together with its standard operating procedure (SOP) is freely available for non-commercial use (CC BY-NC 4.0) at http://cgm.sjtu.edu.cn/eupan/index.html.

Supplementary information

Supplementary data are available at Bioinformatics online.
annotatr: genomic regions in context
Authors: Cavalcante Raymond G , Sartor Maureen A
Published: March 2017

Motivation

Analysis of next-generation sequencing data often results in a list of genomic regions. These may include differentially methylated CpGs/regions, transcription factor binding sites, interacting chromatin regions, or GWAS-associated SNPs, among others. A common analysis step is to annotate such genomic regions to genomic annotations (promoters, exons, enhancers, etc.). Existing tools are limited by a lack of annotation sources and flexible options, the time it takes to annotate regions, an artificial one-to-one region-to-annotation mapping, a lack of visualization options to easily summarize data, or some combination thereof.

Results

We developed the annotatr Bioconductor package to flexibly and quickly summarize and plot annotations of genomic regions. The annotatr package reports all intersections of regions and annotations, giving a better understanding of the genomic context of the regions. A variety of graphics functions are implemented to easily plot numerical or categorical data associated with the regions across the annotations, and across annotation intersections, providing insight into how characteristics of the regions differ across the annotations. We demonstrate that annotatr is up to 27× faster than comparable R packages. Overall, annotatr enables a richer biological interpretation of experiments.

Availability and Implementation

http://bioconductor.org/packages/annotatr/ and https://github.com/rcavalcante/annotatr

Supplementary information

Supplementary data are available at Bioinformatics online.
The obesity paradox, extreme obesity, and long-term outcomes in older adults
with ST-segment elevation myocardial infarction: results from the NCDR
Authors: Neeland Ian J. , Das Sandeep R. , Simon DaJuanicia N. , Diercks Deborah B. , Alexander Karen P. , Wang Tracy Y. , de Lemos James A.
Published: March 2017

Aims

To investigate the obesity paradox and association of extreme obesity with long-term outcomes among older ST-segment elevation myocardial infarction (STEMI) patients.

Methods and results

Nineteen thousand four hundred and ninety-nine patients ≥65 years with STEMI surviving to hospital discharge in NCDR ACTION Registry-GWTG linked to Centers for Medicare and Medicaid Services outcomes between 2007 and 2012 were stratified by body mass index (BMI) (kg/m2) into normal weight (18.5–24.9), overweight (25–29.9), class I (30–34.9), class II (35–39.9), and class III/extreme obese (≥40) categories. Multivariable-adjusted associations were evaluated between BMI categories and mortality by Cox proportional hazards models, and days alive and out of hospital (DAOH) by generalized estimating equations, within 3 years after discharge. Seventy percent of patients were overweight/obese and 3% extremely obese. Normal weight patients were older and more likely to smoke; while extremely obese patients were younger and more likely to be female and black, with lower socioeconomic status and more comorbidity (P ≤ 0.001). A U-shaped association was observed between BMI categories and mortality: patients with class I obesity were at lowest risk, while normal weight [hazard ratio (HR) 1.30, 95% confidence interval (CI) 1.15–1.47] and extremely obese patients (HR 1.33, 95% CI 1.02–1.74) had higher mortality. Normal weight [odds ratio (OR) 0.79, 95% CI 0.68–0.90] and extremely obese (OR 0.73, 95% CI 0.54–0.99) individuals also had lower odds of DAOH.

Conclusion

Mild obesity is associated with lower long-term risk in older STEMI patients, while normal weight and extreme obesity are associated with worse outcomes. These findings highlight hazards faced by an increasing number of older individuals with normal weight or extreme obesity and cardiovascular disease.
HIV-1 strains belonging to large phylogenetic clusters show accelerated escape from integrase inhibitors in cell culture compared with viral isolates from singleton/small clusters
Authors: Brenner Bluma G. , Ibanescu Ruxandra-Ilinca , Oliveira Maureen , Roger Michel , Hardy Isabelle , Routy Jean-Pierre , Kyeyune Fred , Quiñones-Mateu Miguel E. , Wainberg Mark A. ,   on behalf of the Montreal PHI Cohort Study Group
Published: March 2017

Objectives: Viral phylogenetics revealed two patterns of HIV-1 spread among MSM in Quebec. While most HIV-1 strains (n = 2011) were associated with singleton/small clusters (cluster size 1–4), 30 viral lineages formed large networks (cluster size 20–140), contributing to 42% of diagnoses between 2011 and 2015. Herein, tissue culture selections ascertained if large cluster lineages possessed higher replicative fitness than singleton/small cluster isolates, allowing for viral escape from integrase inhibitors.

Methods: Primary HIV-1 isolates from large 20+ cluster (n = 11) or singleton/small cluster (n = 6) networks were passagedin vitro in escalating concentrations of dolutegravir, elvitegravir and lamivudine for 24–36 weeks. Sanger and deep sequencing assessed genotypic changes under selective drug pressure.

Results: Large cluster HIV-1 isolates selected for resistance to dolutegravir, elvitegravir and lamivudine faster than HIV-1 strains forming small clusters. With dolutegravir, large cluster HIV-1 variants acquired solitary R263K (n = 7), S153Y (n = 1) or H51Y (n = 1) mutations as the dominant quasi-species within 8–12 weeks as compared with small cluster lineages where R263K (n = 1/6), S153Y (1/6) or WT species (4/6) were observed after 24 weeks. Interestingly, dolutegravir-associated mutations compromised viral replicative fitness, precluding escalations in concentrations beyond 5–10 nM. With elvitegravir, large cluster variants more rapidly acquired first mutations (T66I, A92G, N155H or S147G) by week 8 followed by sequential accumulation of multiple mutations leading to viral escape (>10 μM) by week 24.

Conclusions: Further studies are needed to understand virological features of large cluster viruses that may favour their transmissibility, replicative competence and potential to escape selective antiretroviral drug pressure.
Apheresis in food allergies
Authors: Dahdah Lamia , Leone Giovanna , Artesani Mariacristina , Riccardi Carla , Mazzina Oscar
Published: March 2017

Purpose of review

The prevalence of IgE-mediated food allergy and anaphylaxis has risen rapidly in developed countries, and countries with rapid industrialization may follow. Therapies include elimination diets, Oral ImmunoTherapy, and the administration of biologics, but high serum IgE levels may preclude their use. Consequently, decreasing IgE becomes a rational approach and could be obtained by immunoapheresis. The aim of this review is to evaluate the rationale and advantages of immunoapheresis.

Recent findings

The majority of the available adsorbers remove aspecifically all classes of immunoglobulins. Recently, IgE-specific adsorbers have been approved. Data on immunoapheresis for the treatment of allergic diseases with pathologically elevated IgE levels are emerging. In atopic dermatitis, this therapy alone seems to be beneficial. IgE-selective apheresis appears to be sufficient to reduce the risk of anaphylaxis in multiple food allergy (MFA) and, when IgE titers are high, to open the way to treatment with Omalizumab.

Prospective studies, with well designed protocols, are needed to assess the efficacy, tolerability, and cost-effectiveness of immunoapheresis in the field of food allergy.
Looking Under the Streetlight? A Framework for Differentiating Performance Measures by Level of Care in a Value-Based Payment Environment
Authors: Naessens James M. , Van Such Monica B. , Nesse Robert E. , Dilling James A. , Swensen Stephen J. , Thompson Kristine M. , Orlowski Janis M. , Santrach Paula J.
Published: March 2017

The majority of quality measures used to assess providers and hospitals are based on easily obtained data, focused on a few dimensions of quality, and developed mainly for primary/community care and population health. While this approach supports efforts focused on addressing the triple aim of health care, many current quality report cards and assessments do not reflect the breadth or complexity of many referral center practices.

In this article, the authors highlight the differences between population health efforts and referral care and address issues related to value measurement and performance assessment. They discuss why measures may need to differ across the three levels of care (primary/community care, secondary care, complex care) and illustrate the need for further risk adjustment to eliminate referral bias.

With continued movement toward value-based purchasing, performance measures and reimbursement schemes need to reflect the increased level of intensity required to provide complex care. The authors propose a framework to operationalize value measurement and payment for specialty care, and they make specific recommendations to improve performance measurement for complex patients. Implementing such a framework to differentiate performance measures by level of care involves coordinated efforts to change both policy and operational platforms. An essential component of this framework is a new model that defines the characteristics of patients who require complex care and standardizes metrics that incorporate those definitions.
How Can Medical Students Add Value? Identifying Roles, Barriers, and Strategies to Advance the Value of Undergraduate Medical Education to Patient Care and the Health System
Authors: Gonzalo Jed D. , Dekhtyar Michael , Hawkins Richard E. , Wolpaw Daniel R.
Published: March 2017

Purpose

As health systems evolve, the education community is seeking to reimagine student roles that combine learning with meaningful contributions to patient care. The authors sought to identify potential stakeholders regarding the value of student work, and roles and tasks students could perform to add value to the health system, including key barriers and associated strategies to promote value-added roles in undergraduate medical education.

Method

In 2016, 32 U.S. medical schools in the American Medical Association’s (AMA’s) Accelerating Change in Education Consortium met for a two-day national meeting to explore value-added medical education; 121 educators, systems leaders, clinical mentors, AMA staff leadership and advisory board members, and medical students were included. A thematic qualitative analysis of workshop discussions and written responses was performed, which extracted key themes.

Results

In current clinical roles, students can enhance value by performing detailed patient histories to identify social determinants of health and care barriers, providing evidence-based medicine contributions at the point-of-care, and undertaking health system research projects. Novel value-added roles include students serving as patient navigators/health coaches, care transition facilitators, population health managers, and quality improvement team extenders. Six priority areas for advancing value-added roles are student engagement, skills, and assessments; balance of service versus learning; resources, logistics, and supervision; productivity/billing pressures; current health systems design and culture; and faculty factors.

Conclusions

These findings provide a starting point for collaborative work to positively impact clinical care and medical education through the enhanced integration of value-added medical student roles into care delivery systems.
Double Versus Single Tendon Transfers to Improve Shoulder Function in Brachial Plexus Birth Palsy
Authors: Greenhill Dustin A. , Smith William R. , Ramsey F.V. , Kozin Scott H. , Zlotolow Dan A.
Published: March 2017

Background:

In children with brachial plexus birth palsy (BPBP) undergoing tendon transfers to augment shoulder external rotation, it is unclear whether transfer of the latissimus dorsi with its combined latissimus dorsi and teres major (cLT) versus isolated teres major (iTM) tendon transfer yield different outcomes.

Methods:

Records of patients with BPBP who underwent shoulder tendon transfers to augment external rotation were retrospectively reviewed. Transfer type (cLT or iTM) was considered indiscriminate by virtue of surgeon preference. Modified Mallet Scale (mMS) and Active Movement Scale scores were recorded. Patients with <12 months’ follow-up, C7 or lower palsy, humeral osteotomy, shoulder procedure(s) within 8 months, microsurgery within 1 year, or recurrent glenohumeral subluxation confirmed by postoperative imaging were excluded. Matched cohorts were identified within each tendon transfer group to yield similar preoperative shoulder function and glenohumeral alignment status. Outcomes for all tendon transfers as well as differences between cLT and iTM cohorts were analyzed.

Results:

Among 121 cLT and 34 iTM transfers, 49 cLT and 14 iTM met the inclusion criteria. Subsequent matching of cohorts yielded 28 patients (14 cLT and 14 iTM). Average age at time of transfer was 3.0±1.4 years. Follow-up averaged 4.1±3.1 years. There were no statistically significant preoperative differences between cohorts, thus matching criteria were validated. Regardless of tendon(s) transferred, mMS external rotation improved (2.2 to 3.5, P<0.001), whereas mMS internal rotation decreased (3.8 to 3.2, P<0.001). When comparing matched cohorts, cLT transfer produced a greater mMS external rotation improvement than iTM (2.1 vs. 1.5, respectively; P=0.025). Loss of midline function (defined as mMS external rotation <3) occurred in 5 (35.7%) cLT and 2 (14.3%) iTM patients.

Conclusions:

Both cLT or iTM transfer are effective at augmenting shoulder external rotation in children with C5-C6 BPBP. Furthermore, cLT transfers may yield a larger improvement in external rotation in certain patients. However, both techniques slightly decrease shoulder internal rotation. Given that more total cLT patients lost midline function among matched cohorts, iTM transfer may still be considered when limited midline function is a concern.

Level of Evidence:

Level III.
Predictors of Outcome in Conservative and Minimally Invasive Surgical Management of Pain Originating From the Sacroiliac Joint
Authors: Dengler Julius , Duhon Bradley , Whang Peter , Frank Clay , Glaser John , Sturesson Bengt , Garfin Steven , Cher Daniel , Rendahl Aaron , Polly David
Published: March 2017

Study Design.

A pooled patient-level analysis of two multicenter randomized controlled trials and one multicenter single-arm prospective trial.

Objective.

The aim of this study was to identify predictors of outcome of conservative and minimally invasive surgical management of pain originating from the sacroiliac joint (SIJ).

Summary of Background Data.

Three recently published prospective trials have shown that minimally invasive SIJ fusion (SIJF) using triangular titanium implants produces better outcomes than conservative management for patients with pain originating from the SIJ. Due to limitations in individual trial sample size, analyses of predictors of treatment outcome were not conducted.

Methods.

We pooled individual patient data from the three trials and used random effects models with multivariate regression analysis to identify predictors for treatment outcome separately for conservative and minimally invasive surgical treatment. Outcome was measured using visual analogue scale (VAS), Oswestry Disability Index (ODI), and EuroQOL-5D (EQ-5D).

Results.

We included 423 patients assigned to either nonsurgical management (NSM, n = 97) or SIJF (n = 326) between 2013 and 2015. The reduction in SIJ pain was 37.9 points larger [95% confidence interval (95% CI) 32.5–43.4, P < 0.0001] in the SIJF group than in the NSM group. Similarly, the improvement in ODI was 18.3 points larger (95% CI 14.3–22.4), P < 0.0001). In NSM, we found no predictors of outcome. In SIJF, a reduced improvement in outcome was predicted by smoking (P = 0.030), opioid use (P = 0.017), lower patient age (P = 0.008), and lower duration of SIJ pain (P = 0.028).

Conclusions.

Our results support the view that SIJF leads to better treatment outcome than conservative management of SIJ pain and that a higher margin of improvement can be predicted in nonsmokers, nonopioid users, and patients of increased age and with longer pain duration.

Level of Evidence: 1
Disassociating Lung Mechanics and Oxygenation in Pediatric Acute Respiratory Distress Syndrome*
Authors: Yehya Nadir , Thomas Neal J.
Published: March 2017

Objectives:

Both oxygenation and peak inspiratory pressure are associated with mortality in pediatric acute respiratory distress syndrome. Since oxygenation and respiratory mechanics are linked, it is difficult to identify which variables, pressure or oxygenation, are independently associated with outcome. We aimed to determine whether respiratory mechanics (peak inspiratory pressure, positive end-expiratory pressure, ΔP [PIP minus PEEP], tidal volume, dynamic compliance [Cdyn]) or oxygenation (Pao2
/Fio2
) was associated with mortality.

Design:

Prospective, observational, cohort study.

Setting:

University affiliated PICU.

Patients:

Mechanically ventilated children with acute respiratory distress syndrome (Berlin).

Interventions:

None.

Measurements and Main Results:

Peak inspiratory pressure, positive end-expiratory pressure, ΔP, tidal volume, Cdyn, and Pao2
/Fio2
were collected at acute respiratory distress syndrome onset and at 24 hours in 352 children between 2011 and 2016. At acute respiratory distress syndrome onset, neither mechanical variables nor Pao2
/Fio2
were associated with mortality. At 24 hours, peak inspiratory pressure, positive end-expiratory pressure, ΔP were higher, and Cdyn and Pao2
/Fio2
lower, in nonsurvivors. In multivariable logistic regression, Pao2
/Fio2
at 24 hours and ΔPao2
/Fio2
(change in Pao2
/Fio2
over the first 24 hr) were associated with mortality, whereas pressure variables were not. Both oxygenation and pressure variables were associated with duration of ventilation in multivariable competing risk regression.

Conclusions:

Improvements in oxygenation, but not in respiratory mechanics, were associated with lower mortality in pediatric acute respiratory distress syndrome. Future trials of mechanical ventilation in children should focus on oxygenation (higher Pao2
/Fio2
) rather than lower peak inspiratory pressure or ΔP, as oxygenation was more consistently associated with outcome.
Increased Early Systemic Inflammation in ICU-Acquired Weakness; A Prospective Observational Cohort Study*
Authors: Witteveen Esther , Wieske Luuk , van der Poll Tom , van der Schaaf Marike , van Schaik Ivo N. , Schultz Marcus J. , Verhamme Camiel , Horn Janneke
Published: March 2017

Objectives:

To investigate whether patients who develop ICU-acquired weakness have a different pattern of systemic inflammatory markers compared with critically ill patients who do not develop ICU-acquired weakness.

Design:

Prospective observational cohort study.

Setting:

Mixed medical-surgical ICU of a tertiary care hospital in the Netherlands.

Patients:

Newly admitted critically ill patients, greater than or equal to 48 hours on mechanical ventilation with a nonneurologic ICU admission diagnosis, were included.

Interventions:

A panel of systemic inflammatory markers and soluble vascular adhesion molecules were measured in plasma samples of day 0, 2, and 4 after ICU admission. ICU-acquired weakness was diagnosed by manual muscle strength testing as soon as patients were awake and attentive.

Measurements and Main Results:

Ninety-nine of 204 included patients developed ICU-acquired weakness. Principal component regression analysis, adjusted for confounders, showed that principal component 1, mainly loaded with interleukin-6, interleukin-8, interleukin-10, and fractalkine, was significantly higher in patients who developed ICU-acquired weakness (odds ratio, 1.35 [95% CI, 1.18–1.55]). Partial least squares-discriminant analysis also showed that these markers were the most important discriminative markers. Mixed-effects models of these markers showed that ICU-acquired weakness was associated with an independent 1.5- to two-fold increase in these markers.

Conclusions:

Systemic inflammation is increased in patients who develop ICU-acquired weakness compared with patients who do not develop ICU-acquired weakness in the first 4 days after ICU admission. This finding is consistent when adjusted for confounders, like disease severity. A group consisting of interleukin-6, interleukin-8, interleukin-10, and fractalkine was identified to be the most important.
Application of Scanning Electron Microscopy With Energy-Dispersive X-Ray Spectroscopy for Analyzing Ocular Surface Particles on Schirmer Strips
Authors: Avula Anuroop , Galor Anat , Blackwelder Patricia , Carballosa-Gautam Melissa , Hackam Abigail S. , Jeng Bennie , Kumar Naresh
Published: March 2017

Purpose:

To demonstrate the application of scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDS) for analyzing Schirmer strips for particle concentration, size, morphology, and type distribution.

Methods:

A cross-sectional design was used. Patients were prospectively recruited from the Miami Veterans Affairs (VA) Healthcare System eye clinic, and they underwent a complete ocular surface examination. The size, type, and chemical composition of particulate matter on Schirmer strips (from the left eye) were analyzed using SEM/EDS.

Results:

Schirmer strips from all 6 patients showed particle loading, ranging from 1 to 33 particles, whereas the blank Schirmer strip that served as a control showed no particle loading. Most particles were coarse, with an average size of 19.7 μm (95% confidence interval 15–24.4 μm). All samples contained organic particles (eg, pollen and mold), and 5 of the 6 samples contained nonorganic particles. The nonorganic particles were composed of silicon, minerals, and metals, including gold and titanium. The size of aluminum and iron particles was ≥62 μm, whereas the size of 2 other metals, zinc and gold, was smaller, that is, <20 μm. Most metal particles were elongated compared with the organic particles, which were round.

Conclusions:

Although SEM/EDS has been extensively used in biomedical research, its novel application to assess the size, morphology, and chemical composition of the ocular surface particles offers an unprecedented opportunity to tease out the role of particulate matter exposure in ocular surface disease and disorders.
Prognostic Value of the Staging System for Eyelid Tumors in the 7th Edition of the American Joint Committee on Cancer Staging Manual
Authors: Ford Joshua , Thakar Sudip , Thuro Bradley , Esmaeli Bita
Published: March 2017

Purpose:

To determine the prognostic value of the staging criteria for eyelid tumors in the 7th edition of the American Joint Committee on Cancer (AJCC) staging manual and to determine, for each type of eyelid tumor, which AJCC T categories are associated with increased risk of nodal metastasis and thus potential usefulness of sentinel lymph node biopsy.

Methods:

Systematic review and analysis of articles found by searching PubMed and Google Scholar using the search terms “AJCC,” “eyelid,” “carcinoma,” and “melanoma.”

Results:

Rates of local recurrence, regional nodal metastasis, and distant metastasis were approximately 7% to 10%, 1% to 9%, and 0% to 0.8%, respectively, for eyelid squamous cell carcinoma; 5% to 6%, 8% to 23%, and 2% and 14%, respectively, for eyelid sebaceous carcinoma; 10%, 10% to 22%, and 19% to 22%, respectively, for eyelid Merkel cell carcinoma (when staged according to the criteria for eyelid carcinoma as opposed to Merkel cell carcinoma), 14%, 5%, and 0%, respectively, for eyelid sweat gland carcinoma; and 2%, 9%, and 6%, respectively, for eyelid melanoma. Overall, the risks of local recurrence and regional nodal and distant metastasis appeared to increase with increasing AJCC T category, although not statistically significant in all studies. Clinical T2b or greater T category was significantly associated with increased risk of nodal metastasis for eyelid squamous cell carcinomas, sebaceous carcinomas, Merkel cell carcinomas (staged with eyelid carcinoma criteria), sweat gland carcinomas, and melanomas. Clinical T3 or greater T category was significantly associated with distant metastasis for eyelid carcinomas and melanomas.

Conclusion:

For eyelid carcinomas and eyelid melanomas, AJCC 7th edition T category correlates with the risks of nodal and distant metastasis, with T2b and larger tumors associated with highest risk of nodal metastasis. Patients with T2b or larger tumors may be candidates for sentinel lymph node biopsy or close nodal surveillance.
Documenting Community Health Worker Roles in Primary Care
Authors: Reinschmidt Kerstin M. , Ingram Maia , Morales Stephanie , Sabo Samantha J. , Blackburn John , Murrieta Lucy , David Cassalyn , Carvajal Scott C.
Published: March 2017

The Patient Protection and Affordable Care Act provided community health workers (CHWs) with new opportunities, and current efforts develop evidence-based guidelines for CHW integration into clinical teams. This qualitative study documents CHW roles and activities in 3 federally qualified health care centers in southern Arizona. Community health worker clinical roles, activities, and integration varied by health center and were in flux. Integration included complementary roles, scheduled and everyday communications with team members, and documentation in the electronic health records. These findings contribute to evidence-based guidelines for CHW integration into clinical teams that are critical to maximizing CHW contributions to patient health improvements.
Rickettsialpox in a Pediatric Patient
Authors: Hananiya Anthonia , Douglas Lindsey C. , Fagan Michele
Published: March 2017

Rickettsialpox is a rare vector-borne rickettsiosis that manifests in hosts living in urban populations, particularly in New York City. The following is a case discussion of a 12-year-old girl with history of fever and right-ankle swelling. She was initially evaluated and treated for cellulitis. She later developed a maculopapular rash completing the classic triad for rickettsialpox: black eschar, papular rash, and fever. Her convalescent rickettsial titers returned positive, confirming the diagnosis of rickettsialpox.
Acute Illness Protocol for Fatty Acid Oxidation and Carnitine Disorders
Authors: Aldubayan Saud H. , Rodan Lance H. , Berry Gerard T. , Levy Harvey L.
Published: March 2017

Inborn errors of metabolism (IEMs) are genetic disorders that disrupt enzyme activity, cellular transport, or energy production. They are individually rare but collectively have an incidence of 1:1000. Most patients with IEMs are followed by a physician with expertise in biochemical genetics (metabolism) but may present outside this setting. Because IEMs can present acutely with life-threatening crises that require specific interventions, it is critical for the emergency medicine physicians, pediatricians, internists, critical care physicians, and biochemical geneticists to be familiar with the initial assessment and management of patients with these disorders. Appropriate early care can be lifesaving. This protocol is not designed to replace the expert consultation of a biochemical geneticist but rather to improve early care and increase the level of comfort of the acute care physician with initial management of fatty acid oxidation and carnitine disorders until specialty consultation is obtained.
Brief Report: High Sensitivity and Specificity of the Cepheid Xpert HIV-1 Qualitative Point-of-Care Test Among Newborns in Botswana
Authors: Ibrahim Maryanne , Moyo Sikhulile , Mohammed Terence , Mupfumi Lucy , Gaseitsiwe Simani , Maswabi Kenneth , Ajibola Gbolahan , Gelman Rebecca , Batlang Oganne , Sakoi Maureen , Auletta-Young Chloe , Makhema Joseph , Lockman Shahin , Shapiro Roger L.
Published: March 2017

Background:

HIV point-of-care (POC) testing allows for early infant HIV diagnosis and treatment, but POC accuracy at birth and in the setting of antiretroviral prophylaxis for the prevention of mother-to-child HIV transmission is unknown.

Methods:

We evaluated the Cepheid Xpert HIV-1 Qual POC test against the Roche Taqman HIV-1 DNA polymerase chain reaction (PCR) platform using dried blood spots from 15 HIV-infected and 75 HIV-exposed uninfected newborns. These infants were screened for HIV at <96 hours of life at 5 hospital maternity wards in Botswana; all infants received postexposure antiretroviral prophylaxis with single-dose nevirapine and zidovudine, and most mothers received 3-drug antiretroviral therapy in pregnancy and at delivery.

Results:

Fourteen of the 15 PCR positive samples tested positive by Cepheid POC, yielding a sensitivity of 93.3% (95% confidence interval: 68.1 to 99.8). Baseline viral load among positive infants ranged from <40 to >10,000,000 copies/mL, with a median of 2403 copies/mL. The HIV RNA for the infant with false-negative POC testing was 1661 copies/mL. Of note, 2 infants with low HIV RNA (<40 and 272 copies/mL) were correctly identified as HIV positive by Cepheid POC. All the 75 PCR-negative samples tested negative by Cepheid POC, yielding a specificity of 100% (95% confidence interval: 96.1 to 100).

Discussion:

Our study demonstrates high sensitivity and specificity for the Cepheid POC assay in the first week of life despite early infection and antiretroviral prophylaxis. This platform may be a useful approach for adding early infant HIV diagnosis to current testing programs.
Mechanocellular models of epithelial morphogenesis
Authors: Fletcher Alexander G. , Cooper Fergus , Baker Ruth E.
Published: March 2017

Embryonic epithelia achieve complex morphogenetic movements, including in-plane reshaping, bending and folding, through the coordinated action and rearrangement of individual cells. Technical advances in molecular and live-imaging studies of epithelial dynamics provide a very real opportunity to understand how cell-level processes facilitate these large-scale tissue rearrangements. However, the large datasets that we are now able to generate require careful interpretation. In combination with experimental approaches, computational modelling allows us to challenge and refine our current understanding of epithelial morphogenesis and to explore experimentally intractable questions. To this end, a variety of cell-based modelling approaches have been developed to describe cell–cell mechanical interactions, ranging from vertex and ‘finite-element’ models that approximate each cell geometrically by a polygon representing the cell's membrane, to immersed boundary and subcellular element models that allow for more arbitrary cell shapes. Here, we review how these models have been used to provide insights into epithelial morphogenesis and describe how such models could help future efforts to decipher the forces and mechanical and biochemical feedbacks that guide cell and tissue-level behaviour. In addition, we discuss current challenges associated with using computational models of morphogenetic processes in a quantitative and predictive way.

This article is part of the themed issue ‘Systems morphodynamics: understanding the development of tissue hardware’.