bluuebunny/crossref_metadata_2025 huggingface dataset:
Local and global dynamics of Ramsey model: From continuous to discrete time
Authors: Guzowska Malgorzata , Michetti Elisabetta
Published: May 2018

The choice of time as a discrete or continuous variable may radically affect equilibrium stability in an endogenous growth model with durable consumption. In the continuous-time Ramsey model [F. P. Ramsey, Econ. J. 38(152), 543–559 (1928)], the steady state is locally saddle-path stable with monotonic convergence. However, in the discrete-time version, the steady state may be unstable or saddle-path stable with monotonic or oscillatory convergence or periodic solutions [see R.-A. Dana et al., Handbook on Optimal Growth 1 (Springer, 2006) and G. Sorger, Working Paper No. 1505 (2015)]. When this occurs, the discrete-time counterpart of the continuous-time model is not consistent with the initial framework. In order to obtain a discrete-time Ramsey model preserving the main properties of the continuous-time counterpart, we use a general backward and forward discretisation as initially proposed by Bosi and Ragot [Theor. Econ. Lett. 2(1), 10–15 (2012)]. The main result of the study here presented is that, with this hybrid discretisation method, fixed points and local dynamics do not change. For what it concerns global dynamics, i.e., long-run behavior for initial conditions taken on the state space, we mainly perform numerical analysis with the main scope of comparing both qualitative and quantitative evolution of the two systems, also varying some parameters of interest.
Electronic properties of GdxBi2−xSe3 single crystals analyzed by Shubnikov-de Haas oscillations
Authors: Kim Soo-Whan , Jung Myung-Hwa
Published: May 2018

Magnetically doped topological insulators have been significantly researched for unlocking the nontrivial topological phases and the resultant potential applications for spintronics. We report the effect of antiferromagnetic order induced by Gd substitution on the electronic properties of GdxBi2−xSe3 single crystals by analyzing the Shubnikov-de Haas oscillations. Antiferromagnetic order of Gd ions affects the 2D surface state in Bi2Se3 and changes the effective mass and lifetime of charge carriers. These observations suggest a strong correlation of 2D surface electrons with the antiferromagnetic ordering, where the itinerant electrons are bound to the Gd ions to mediate the antiferromagnetic interaction.
Low cost and thin metasurface for ultra wide band and wide angle polarization insensitive radar cross section reduction
Authors: Ameri Edris , Esmaeli Seyed Hassan , Sedighy Seyed Hassan
Published: May 2018

A planar low cost and thin metasurface is proposed to achieve ultra-wideband radar cross section (RCS) reduction with stable performance with respect to polarization and incident angles. This metasurface is composed of two different artificial magnetic conductor unit cells arranged in a chessboard like configuration. These unit cells have a Jerusalem cross pattern with different thicknesses, which results in wideband out-phase reflection and RCS reduction, consequently. The designed metasurface reduces RCS more than 10-dB from 13.6 GHz to 45.5 GHz (108% bandwidth) and more than 20-dB RCS from 15.2 GHz to 43.6 GHz (96.6%). Moreover, the 10-dB RCS reduction bandwidth is very stable (more than 107%) for both TE and TM polarizations. The good agreement between simulations and measurement results proves the design, properly. The ultra-wide bandwidth, low cost, low profile, and stable performance of this metasurface prove its high capability compared with the state-of-the-art references.
Multidisciplinary design optimization of the belt drive system considering both structure and vibration characteristics based on improved genetic algorithm
Authors: Yuan Yongliang , Song Xueguan , Sun Wei , Wang Xiaobang
Published: May 2018

The dynamic performance of a belt drive system is composed of many factors, such as the efficiency, the vibration, and the optimal parameters. The conventional design only considers the basic performance of the belt drive system, while ignoring its overall performance. To address all these challenges, the study on vibration characteristics and optimization strategies could be a feasible way. This paper proposes a new optimization strategy and takes a belt drive design optimization as a case study based on the multidisciplinary design optimization (MDO). The MDO of the belt drive system is established and the corresponding sub-systems are analyzed. The multidisciplinary optimization is performed by using an improved genetic algorithm. Based on the optimal results obtained from the MDO, the three-dimension (3D) model of the belt drive system is established for dynamics simulation by virtual prototyping. From the comparison of the results with respect to different velocities and loads, the MDO method can effectively reduce the transverse vibration amplitude. The law of the vibration displacement, the vibration frequency, and the influence of velocities on the transverse vibrations has been obtained. Results show that the MDO method is of great help to obtain the optimal structural parameters. Furthermore, the kinematics principle of the belt drive has been obtained. The belt drive design case indicates that the proposed method in this paper can also be used to solve other engineering optimization problems efficiently.
Emergence of two lamellas during impact of compound droplets
Authors: Liu Dongdong , Tran Tuan
Published: May 2018

A compound droplet consisting of water and silicone oil either spreads or splashes upon impacting a solid surface. We show that the transition from spreading to splashing of this type of compound droplet can be changed by varying the volumetric oil ratio in the droplets. In the spreading regime, we observe a surprising emergence of two lamellas spreading one after the other: the first spreading lamella consists of only oil and the trailing one water. We show that the two lamellas eventually meet, significantly affecting the spreading dynamics. Finally, we quantify the maximum spreading radius and show that it is a function of both the impact velocity and the volumetric oil ratio.
Communication: From close-packed to topologically close-packed: Formation of Laves phases in moderately polydisperse hard-sphere mixtures
Authors: Lindquist Beth A. , Jadrich Ryan B. , Truskett Thomas M.
Published: May 2018

Particle size polydispersity can help to inhibit crystallization of the hard-sphere fluid into close-packed structures at high packing fractions and thus is often employed to create model glass-forming systems. Nonetheless, it is known that hard-sphere mixtures with modest polydispersity still have ordered ground states. Here, we demonstrate by computer simulation that hard-sphere mixtures with increased polydispersity fractionate on the basis of particle size and a bimodal subpopulation favors the formation of topologically close-packed C14 and C15 Laves phases in coexistence with a disordered phase. The generality of this result is supported by simulations of hard-sphere mixtures with particle-size distributions of four different forms.
Oxidation mechanism of thin Cu films: A gateway towards the formation of single oxide phase
Authors: Choudhary Sumita , Sarma J. V. N. , Pande Surojit , Ababou-Girard Soraya , Turban Pascal , Lepine Bruno , Gangopadhyay Subhashis
Published: May 2018

Controlled thermal oxidations of thin copper films at relatively lower temperatures (up to 500°C) leading towards the formation of a single phase of copper oxide are investigated where the oxidation temperature, duration, oxygen partial pressure, film thickness and the crystallographic orientations play very crucial roles to significantly control the final phase of the copper oxide. Thin Cu films of thicknesses 100-1000 nm were deposited on glass and silicon substrates using the vacuum assisted thermal evaporation technique. Oxidations of those Cu films were performed at different temperatures for variable durations in air ambient as well as oxygen ambient conditions. Four probe resistivity measurement, x-ray diffraction (XRD), Raman spectroscopy, ultraviolet–visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM) and x-ray photoemission spectroscopy (XPS) techniques have been used to characterize the oxide films. At a thermodynamic equilibrium, it has been observed that the oxide phase is solely determined by the oxidation temperature, however, the oxygen partial pressure can significantly alter this temperature range. In case of thermal oxidation in air, the initial oxidation of the copper films starts at about 150 °C, but a well ordered crystalline phase of the cuprous oxide (Cu2O) is observed only above 200 °C. However, the cupric oxide (CuO) phase starts to appear only above 320 °C. The details of the oxidation mechanism of the Cu film are explained with a probable schematic model in terms of thermal diffusion as well as the chemical reactivity.
Electrostatic waves driven by electron beam in lunar wake plasma
Authors: Sreeraj T. , Singh S. V. , Lakhina G. S.
Published: May 2018

A linear analysis of electrostatic waves propagating parallel to the ambient field in a four component homogeneous, collisionless, magnetised plasma comprising fluid protons, fluid He++, electron beam, and suprathermal electrons following kappa distribution is presented. In the absence of electron beam streaming, numerical analysis of the dispersion relation shows six modes: two electron acoustic modes (modes 1 and 6), two fast ion acoustic modes (modes 2 and 5), and two slow ion acoustic modes (modes 3 and 4). The modes 1, 2 and 3 and modes 4, 5, and 6 have positive and negative phase speeds, respectively. With an increase in electron beam speed, the mode 6 gets affected the most and the phase speed turns positive from negative. The mode 6 thus starts to merge with modes 2 and 3 and generates the electron beam driven fast and slow ion acoustic waves unstable with a finite growth. The electron beam driven slow ion-acoustic waves occur at lower wavenumbers, whereas fast ion-acoustic waves occur at a large value of wavenumbers. The effect of various other parameters has also been studied. We have applied this analysis to the electrostatic waves observed in lunar wake during the first flyby of the ARTEMIS mission. The analysis shows that the low (high) frequency waves observed in the lunar wake could be the electron beam driven slow (fast) ion-acoustic modes.
Leaf heteroblasty in eucalypts: biogeographic evidence of ecological function
Authors: Vlasveld Carolyn , O'Leary Benjamin , Udovicic Frank , Burd Martin
Published: May 2018

Leaves that develop on seedlings, young saplings or regenerative shoots of many eucalypt species are strikingly different in morphology from the typical leaves of more mature plants; a developmental pattern known as heteroblasty. We measured dimorphism between juvenile and adult leaves in shape and size, leaf mass per unit area, and vein frequency in a continent-wide sample of Angophora, Corymbia and Eucalyptus species. We tested whether heteroblasty in this group is an adaptation to shading by comparing the degree of juvenile–adult leaf dimorphism with the canopy closure (measured by the leaf area index) of the habitat in which species occurred. No pattern emerged for heteroblasty in leaf shape and size or leaf mass per unit area, but there was a significant relationship (accounting for phylogenetic relationships) between the degree of juvenile–adult dimorphism in vein frequency and habitat leaf area index. Juvenile leaves tended to have more widely spaced veins than adult leaves of the same species, in regions with more closed vegetative canopies. This evidence suggests that eucalypt heteroblasty is, at least in part, a hydraulic adaptation to the different conditions faced by younger and older plants in higher productivity regions with denser vegetation.
Effect of weaning strategy on performance, behaviour and blood parameters of yak calves (Poephagus grunniens)
Authors: Liu Peipei , Liu Shujie , Degen Allan , Qiu Qiang , Dong Quanmin , Jing Xiaoping , Zhang Jiaojiao , Yan Qi , Zheng Wenming , Ding Luming
Published: May 2018

Early weaning can improve the body condition and reproductive performance of cows, but can be very stressful to both the calf and cow. The objectives of this study were to examine and compare the performance, behaviour and blood parameters of yak calves that were weaned using different methods. Twenty-six calves (94.3 ± 2.4 days old) were assigned to four weaning treatments: (1) weaned naturally following ad libitum sucking (NW, n = 13); (2) weaned abruptly and separated permanently from their mothers (AW, n = 5); (3) separated temporarily from their mothers for 15 days and then reunited (TW, n = 5); and (4) fitted with nose plates to prevent sucking for 15 days but allowed free access to their mothers (NP, n = 3). Girth size, as a measure of calf performance, was largest in NW and AW calves, intermediate in NP calves and smallest in TW calves. This indicated that the AW calves were able to consume adequate energy to compensate for the absence of milk. The weaned calves (TW and NP) spent more time grazing and, in general, played less than NW calves. In addition, TW calves stood more but walked less, whereas NP calves lay more but grazed and stood less than NW calves. Blood insulin was lower on Day 19 in the TW calves than in the other three treatments. We concluded that abrupt and permanent weaning was an appropriate strategy for yak calves on the Qinghai-Tibetan plateau.
Torque Teno Virus in HIV-infected transgender in Surakarta, Indonesia
Authors: Hartono  , Prasetyo Afiono Agung , Fanani Mohammad
Published: May 2018

Torque Teno Virus (TTV) is a circular single-stranded DNA virus that may co-infected with human immunodeficiency virus (HIV), especially in the high-risk community e.g. the transgender performing high-riskbehavior. TTV shows an increased viremia in HIV patients and maybe influence the HIV clinical progression. Blood samples collected from transgender performing high-riskbehavior in Surakarta were tested by serological and molecular assays to detect the presence of HIV infection. The blood samples with HIV positive status were then tested by a nested polymerase chain reaction (PCR) to detect the presentation of TTV DNA. The amplified PCR products were molecularly cloned and subjected to sequence analysis. TTV DNA was detected in 40.0% HIV-positive samples. The molecular characterization revealed that the most prevalent was genogroup 3, followed by genogroup 2 and 1, respectively. TTV was detected in HIV-infected transgender performing high-riskbehavior in Surakarta with high infection rate.
Molecular analysis of Toxoplasma gondii Surface Antigen 1 (SAG1) gene cloned from Toxoplasma gondii DNA isolated from Javanese acute toxoplasmosis
Authors: Haryati Sri , Prasetyo Afiono Agung , Sari Yulia , Dharmawan Ruben
Published: May 2018

Toxoplasma gondii Surface Antigen 1 (SAG1) is often used as a diagnostic tool due to its immunodominant-specific as antigen. However, data of the Toxoplasma gondii SAG1 protein from Indonesian isolate is limited. To study the protein, genomic DNA was isolated from a Javanese acute toxoplasmosis blood samples patient. A complete coding sequence of Toxoplasma gondii SAG1 was cloned and inserted into an Escherichia coli expression plasmid and sequenced. The sequencing results were subjected to bioinformatics analysis. The Toxoplasma gondii SAG1 complete coding sequences were successfully cloned. Physicochemical analysis revealed the 336 aa of SAG1 had 34.7 kDa of weight. The isoelectric point and aliphatic index were 8.4 and 78.4, respectively. The N-terminal methionine half-life in Escherichia coli was more than 10 hours. The antigenicity, secondary structure, and identification of the HLA binding motifs also had been discussed. The results of this study would contribute information about Toxoplasma gondii SAG1 and benefits for further works willing to develop diagnostic and therapeutic strategies against the parasite.
Re‐Examining the SNAP Benefit Cycle Allowing for Heterogeneity
Authors: Dorfman Jeffrey H , Gregory Christian , Liu Zhongyuan , Huo Ran
Published: May 2018

A well‐known feature of the Supplemental Nutrition Assistance Program (SNAP) is that some recipients spend a disproportionate amount of their monthly benefit early in the month. Using a finite mixture model that optimally separates households into two groups, coupled with the National Household Food Acquisition and Purchase Survey, we re‐examine this spending pattern. Results show that a minority of SNAP recipients cause the benefit cycle by spending, on average, two‐thirds of their monthly benefit within the first four days. A potential implication of these findings is that more frequent SNAP benefit disbursal or educational programs designed to encourage smoother spending over the month might be of benefit to some SNAP households.
Estimating Willingness to Pay for E85 in the United States Using an Intercept Survey of Flex Motorists
Authors: Pouliot Sébastien , Liao Kenneth A. , Babcock Bruce A.
Published: May 2018

Compliance with the Renewable Fuel Standard (RFS) in the United States will require price incentives for a substantial number of motorists with flex‐fuel vehicles to switch to high ethanol‐gasoline blends. Existing estimates of motorists’ willingness to pay for high‐ethanol blends use data from Brazil, data generated when prices greatly favored low‐ethanol blends, or stated preference data collected from mail and online surveys. We conducted an intercept survey of flex motorists as they refueled in five U.S. states. We overcome the problem caused by sample prices favoring low‐ethanol blends by augmenting revealed preference data with stated preference data. A sample‐selection problem arises because motorists with high willingness to pay seek out the relatively few stations that sell high‐ethanol blends. We use responses from two questions to inform sample selection. We find the average U.S. motorist requires a substantial discount to switch to high ethanol blends beyond the price that equates the cost per mile of driving.
Trajectories of Aging Among U.S. Older Adults: Mixed Evidence for a Hispanic Paradox
Authors: Tarraf Wassim , Jensen Gail A , Dillaway Heather E , Vásquez Priscilla M , González Hector M
Published: May 2018

Objectives

A well-documented paradox is that Hispanics tend to live longer than non-Hispanic Whites (NHW), despite structural disadvantages. We evaluate whether the “Hispanic paradox” extends to more comprehensive longitudinal aging classifications and examine how lifecourse factors relate to these groupings.

Methods

We used biennial data (1998–2014) on adults aged 65 years and older at baseline from the Health and Retirement Study. We use joint latent class discrete time and growth curve modeling to identify trajectories of aging, and multinomial logit models to determine whether U.S.-born (USB-H) and Foreign-born (FB-H) Hispanics experience healthier styles of aging than non-Hispanic Whites (NHW), and test how lifecycle factors influence this relationship.

Results

We identify four trajectory classes including, “cognitive unhealthy,” “high morbidity,” “nonaccelerated”, and “healthy.” Compared to NHWs, both USB-H and FB-H have higher relative risk ratios (RRR) of “cognitive unhealthy” and “high morbidity” classifications, relative to “nonaccelerated.” These patterns persist upon controlling for lifecourse factors. Both Hispanic groups, however, also have higher RRRs for “healthy” classification (vs “nonaccelerated”) upon adjusting for adult achievements and health behaviors.

Discussion

Controlling for lifefcourse factors USB-H and FB-H have equal or higher likelihood for “high morbidity” and “cognitive unhealthy” classifications, respectively, relative to NHWs. Yet, both groups are equally likely of being in the “healthy” group compared to NHWs. These segregations into healthy and unhealthy groups require more research and could contribute to explaining the paradoxical patterns produced when population heterogeneity is not taken into account.
Regulation dynamics of exploited and protected populations of Haliotis roei, and their response to a marine heatwave
Authors: Hart Anthony M , Strain Lachlan W S , Brown Jamin
Published: May 2018

Exploited and protected populations of Haliotis roei in Western Australia were significantly perturbed by a marine heatwave of 2010/11. The immediate effects were a decline in large animals and recruitment, followed by a lagged decline in the spawning biomass. The data describing these effects were fitted to models of the population dynamic transitions. Depensatory density dependence in recruitment is offset by compensatory density dependence in during replacement and together they create the population equilibrium points. Equilibrium densities were highly influenced by the environmental perturbation, with observed patterns suggesting a temporary ‘regime shift’ had occurred. The main implication for management is to maximise spawning biomass as recruitment is positively correlated with it with some evidence of an Allee effect at low spawning densities, but no evidence of compensatory density dependence at high densities. Development of forecasting models that utilised pre-recruit densities, adjusted for density-dependent replacement, and incorporated an environmental effect, assisted early-management intervention to stock declines. Such an approach is an alternative to traditional assessments which recommend using biological reference points that assume population regulation occurs in the recruitment transition. This assumption cannot easily explain why the high density unfished stock showed the least resilience to the environmental perturbation.
Patient similarity by joint matrix trifactorization to identify subgroups in acute myeloid leukemia
Authors: Vitali F , Marini S , Pala D , Demartini A , Montoli S , Zambelli A , Bellazzi R
Published: May 2018

Objective

Computing patients’ similarity is of great interest in precision oncology since it supports clustering and subgroup identification, eventually leading to tailored therapies. The availability of large amounts of biomedical data, characterized by large feature sets and sparse content, motivates the development of new methods to compute patient similarities able to fuse heterogeneous data sources with the available knowledge.

Materials and Methods

In this work, we developed a data integration approach based on matrix trifactorization to compute patient similarities by integrating several sources of data and knowledge. We assess the accuracy of the proposed method: (1) on several synthetic data sets which similarity structures are affected by increasing levels of noise and data sparsity, and (2) on a real data set coming from an acute myeloid leukemia (AML) study. The results obtained are finally compared with the ones of traditional similarity calculation methods.

Results

In the analysis of the synthetic data set, where the ground truth is known, we measured the capability of reconstructing the correct clusters, while in the AML study we evaluated the Kaplan-Meier curves obtained with the different clusters and measured their statistical difference by means of the log-rank test. In presence of noise and sparse data, our data integration method outperform other techniques, both in the synthetic and in the AML data.

Discussion

In case of multiple heterogeneous data sources, a matrix trifactorization technique can successfully fuse all the information in a joint model. We demonstrated how this approach can be efficiently applied to discover meaningful patient similarities and therefore may be considered a reliable data driven strategy for the definition of new research hypothesis for precision oncology.

Conclusion

The better performance of the proposed approach presents an advantage over previous methods to provide accurate patient similarities supporting precision medicine.
FTO is a transcriptional repressor to auto-regulate its own gene and potentially associated with homeostasis of body weight
Authors: Liu Shu-Jing , Tang Hui-Ling , He Qian , Lu Ping , Fu Tao , Xu Xu-Ling , Su Tao , Gao Mei-Mei , Duan Shumin , Luo Yan , Long Yue-Sheng
Published: May 2018

Fat mass and obesity-associated (FTO) protein is a ferrous ion (Fe2+)/2-oxoglutarate (2-OG)-dependent demethylase preferentially catalyzing m6A sites in RNA. The FTO gene is highly expressed in the hypothalamus with fluctuation in response to various nutritional conditions, which is believed to be involved in the control of whole body metabolism. However, the underlying mechanism in response to different nutritional cues remains poorly understood. Here we show that ketogenic diet-derived ketone body β-hydroxybutyrate (BHB) transiently increases FTO expression in both mouse hypothalamus and cultured cells. Interestingly, the FTO protein represses Fto promoter activity, which can be offset by BHB. We then demonstrate that FTO binds to its own gene promoter, and Fe2+, but not 2-OG, impedes this binding and increases FTO expression. The BHB-induced occupancy of the promoter by FTO influences the assembly of the basal transcriptional machinery. Importantly, a loss-of-function FTO mutant (I367F), which induces a lean phenotype in FTOI367F mice, exhibits augmented binding and elevated potency to repress the promoter. Furthermore, FTO fails to bind to its own promoter that promotes FTO expression in the hypothalamus of high-fat diet-induced obese and 48-h fasting mice, suggesting a disruption of the stable expression of this gene. Taken together, this study uncovers a new function of FTO as a Fe2+-sensitive transcriptional repressor dictating its own gene switch to form an auto-regulatory loop that may link with the hypothalamic control of body weight.
Impact of Outpatient vs Inpatient ABSSSI Treatment on Outcomes: A Retrospective Observational Analysis of Medical Charts Across US Emergency Departments
Authors: Bookstaver P Brandon , Jenkins Timothy C , Stenehjem Edward , Doron Shira , Brown Jack , Goldwater Shannon H , Lopes Carlos , Haynes Angela , Udeze Chuka , Mo Yifan , Gillard Patrick , Liu Yan , Keyloun Katelyn
Published: May 2018

Background

The objective of this study was to characterize treatment of patients with acute bacterial skin and skin structure infections (ABSSSIs) and describe the association between hospital admission and emergency department (ED) visits or readmissions within 30 days after initial episode of care (IEC).

Methods

This was a retrospective, observational, cohort study of adults with ABSSSI who presented to an ED between July 1, 2012, and June 30, 2013. Patient, health care facility, and treatment characteristics, including unplanned ED visits or readmissions, were obtained through manual chart review and abstraction. Adjusted logistic regression analysis examined likelihood of all-cause unplanned ED visits or readmissions between admitted and nonadmitted patients.

Results

Records from 1527 ED visits for ABSSSI from 40 centers were reviewed (admitted, n = 578 [38%]; nonadmitted, n = 949 [62%]). Admitted patients were typically older (mean age, 52.2 years vs 43.0 years), more likely to be morbidly obese (body mass index > 40 kg/m2; 17.3% vs 9.1%), and had more comorbidities (Charlson Comorbidity Index ≥ 4; 24.4% vs 6.8%) compared with those not admitted. In the primary analysis, adjusted logistic regression, controlling for comorbidities and severity of illness, demonstrated that there was a similar likelihood of all-cause unplanned ED visits or readmissions between admitted and nonadmitted patients (odds ratio, 1.03; 95% confidence interval, 0.74–1.43; P = .87).

Conclusions

ABSSSI treatment pathways leveraging outpatient treatment vs hospital admission support similar likelihood of unplanned 30-day ED visits or readmissions, an important clinical outcome and quality metric at US hospitals. Further research regarding the decision criteria around hospital admission to avoid potentially unnecessary hospitalizations is warranted.
Hypertension guideline update
Authors: DePalma Sondra M. , Himmelfarb Cheryl Dennison , MacLaughlin Eric J. , Taler Sandra J.
Published: May 2018

In the United States, hypertension affects about one-third of adults and contributes to one out of every seven deaths. Evidence-based treatment is associated with reductions in incidence of stroke, myocardial infarction, and heart failure as well as associated disability and death. This article reviews the ACC/AHA Task Force on Clinical Practice Guidelines' 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults. Key changes include reclassification of BP stages and lowering of hypertension treatment goals.
High-intensity Interval Training and Continuous Aerobic Exercise Interventions to Promote Self-initiated Quit Attempts in Young Adults Who Smoke: Feasibility, Acceptability, and Lessons Learned From a Randomized Pilot Trial
Authors: Allen Alicia , Carlson Samantha C. , Bosch Tyler A. , Eberly Lynn E. , Okuyemi Kola , Nair Uma , Gordon Judith S.
Published: May 2018

Objectives:

While exercise significantly reduces craving for cigarettes, the effect of exercise on self-initiation of quit attempts is less known. Therefore, this randomized pilot study explored the effect of starting an exercise program on self-initiated quit attempts, and also the feasibility and acceptability of a novel exercise intervention, high-intensity interval training (HIIT), as compared with a more traditional continuous aerobic (CA) exercise intervention.

Methods:

Participants smoked (≥5 cigarettes/d), were aged 18 to 40 years, and wanted to increase their exercise. Participants were randomized into 1 of 3 groups: HIIT, CA, and delayed control. All participants attended follow-up visits at weeks 4, 8, and 12. Outcomes included measures of feasibility (eg, visit attendance) and acceptability (eg, satisfaction), and also changes in smoking behavior (eg, quit attempts during follow-up) and proxies to quit attempts (eg, positive affect).

Results:

Overall, there were no differences in terms of feasibility and acceptability between the HITT (n = 12) and CA (n = 9) groups. Based on both self-report and objective measurement, the exercise groups (HIIT and CA) increased their physical activity as compared with the delayed treatment group (n = 11). Compared with HIIT and delayed control, CA (n = 9) had significant favorable changes in positive affect (eg, at week 8, HIIT: +0.25 ± 2.21, delayed control: −5.11 ± 2.23, CA: +5.50 ± 2.23; P = 0.0153).

Conclusions:

These observations suggest that HIIT is as feasible and acceptable as CA, though CA may have a more favorable effect on proxies to quit attempts (eg, positive affect). Fully powered studies are needed to examine the effect of HIIT versus CA on quit attempts.
Radiation Exposure to the Surgeons and Patients in Fluoroscopic-Guided Segmental Pedicle Screw Placement for Pediatric Scoliosis
Authors: Yoshihara Hiroyuki , Paulino Carl B.
Published: May 2018

Study Design.

Prospective case series.

Objective.

To analyze the radiation exposure to the surgeons and patients in fluoroscopic-guided segmental pedicle screw placement for pediatric scoliosis.

Summary of Background Data.

Fluoroscopic-guided pedicle screw placement is a safer technique for pedicle screw placement in spinal deformity. However, radiation exposure is a concern, particularly for spine surgeons due to the requirement of multiple pedicle screws in spinal deformity surgery.

Methods.

We measured radiation dose to the surgeons and pediatric patients undergoing scoliosis surgery by a team of two surgeons (S1 and S2) from March 2016 to December 2017. Surgery was performed using fluoroscopic-guided segmental pedicle screw placement. The dosimeters were placed at the forehead, inside and outside thyroid shield, both hands, back, and suprapubic under lead apron for each surgeon; and at the thyroid and gonads for patients.

Results.

Thirty patients were included in the study. The mean numbers of pedicle screws per case were 23.2 ± 3.4. The mean dose (mrem) per case for the two surgeons S1 and S2 was 0.07 and 0.47 at forehead, 0.07 and 0.37 at outside thyroid shield, 0.00 and 0.30 at inside thyroid shield, 16.87 and 13.73 at right hand, 6.07 and 11.37 at left hand, 0.50 and 0.00 at back, and 0.00 and 0.00 at suprapubic under lead apron, respectively. The mean dose (mrem) per case for the male and female patient was 3.67 and 14.71 for thyroid and 3.83 and 3.17 for gonads, respectively.

Conclusion.

The results of this study demonstrated that radiation exposure to the spine surgeons and patients is low using fluoroscopic-guided segmental pedicle screw technique for pediatric scoliosis surgery. Both hands of the surgeons received much higher doses compared to other body areas and, and thus radiation-reducing gloves and careful attention to surgeon's hands need to be considered for this procedure.

Level of Evidence: 2
The Relationship Between Fear-Avoidance and Neuromuscular Measures of Function in Patients With Adult Degenerative Scoliosis
Authors: Haddas Ram , Lieberman Isador H. , Block Andrew
Published: May 2018

Study Design.

A prospective cohort study.

Objective.

To examine the relationship of fear-avoidance beliefs and neuromuscular activity during gait in adult degenerative scoliosis (ADS) patients.

Summary of Background Data.

Among patients with chronic spine pain, fear-avoidance beliefs are predictive of poor surgical outcomes. Fear-avoi occurs when patients perceive that movement will worsen underlying physical problems. This process leads them to restrict activity, which further heightens emotional distress. Patients with ADS have previously been shown to have an altered gait pattern. Electromyography is evolving into a useful tool to further our understanding of the pathologic manifestations of ADS during gait.

Methods.

Fifty ADS patients completed the Tampa Scale for Kinesiophobia (TSK) questionnaire and the Fear Avoidance Beliefs Questionnaire (FABQ). Surface electromyography electrodes were bilaterally placed on trunk and lower extremity muscles. Each patient performed a series of over-ground gait trials at a self-selected comfortable speed. Pearson Product Correlation analysis was used to determine the relationship between the self-reported fear of movement measures and the neuromuscular gait analysis biomechanical data.

Results.

The TSK total score and the FABQ physical were correlated with muscle onset of the External Oblique (P = 0.005), Gluteus Maximus (P = 0.018), Multifidi (P = 0.017), Erector Spinae (P = 0.014), Rectus Femoris (i = 0.008), Semitendinosus (P = 0.012), Tibilais Anterior (P = 0.012), and Medial Gastrocnemius (P = 0.010). Furthermore, the TSK total score, FABQ physical portion were correlated with muscle peak activity of Medial Gastrocnemius (P = 0.007), Multifidi (P = 0.014), and Tibilais Anterior (i = 0.050) and time to peak muscle activity of the Medial Gastrocnemius (P = 0.006) and Semitendinosus P = 0.038.

Conclusion.

This study demonstrates a strong correlation between neuromuscular gait parameters and fear-avoidance of movement which may reflect ADS patient experiences during ambulation. Further, it demonstrates that there are different aspects of fear-avoidance that may influence gait parameters. This study extends previous research on the role of fear-avoidance to include patients with spinal deformity.

Level of Evidence: 3
Free Functional Muscle Transfer for Thumb Opposition
Authors: Seal Alexander , Stevanovic Milan
Published: May 2018

Traumatic injuries and other conditions resulting in thenar loss and loss of opposition function can cause significant functional limitations. There are limited options available to restore function and bulk to the thenar musculature. A 26-year-old man had an unfortunate accident at work with a machine mixer creating a crush injury to his left hand. This required several debridements due to the tissue injury and resulted in loss of the thenar muscles and ability to oppose the thumb. He recovered well from the initial injury, however, was left with difficulty with grasp and holding objects due to the loss of thenar motion and strength. His function was also affected by the loss of bulk. He successfully underwent a free functional muscle reconstruction with his serratus anterior. This case report is a description of his reconstruction and a review of the literature. The patient had an excellent outcome. He obtained active opposition and improved grip strength, improving his activities of daily living and vocational life. The serratus anterior muscle can successfully be used for thumb opposition reconstruction. This case report demonstrates good outcomes for both motion and bulk restoration.
The Role of Stem Cells in Dupuytren’s Disease: A Review
Authors: Tan Kirin , Withers Aaron H. J. , Tan Swee T. , Itinteang Tinte
Published: May 2018

The pathogenesis of Dupuytren’s disease (DD) remains unclear although there is increasing evidence supporting the role of stem cells in this and other fibrotic conditions. This review examines the role of DD tissue-associated embryonic stem cells (ESCs) and mesenchymal stem cells (MSCs), and circulating fibrocytes and circulating MSCs, in the biology of DD. It is exciting to infer that dysfunction of an upstream ESC-like population within the affected tissue leads to the downstream development and proliferation of aberrant myofibroblasts through a putative MSC intermediate. This ESC-like population may be a potential novel therapeutic target through modulation of the renin-angiotensin system. Furthermore, circulating CD34+ fibrocytes and MSCs either derived from the bone marrow, peripheral blood cells, or DD-associated ESC-like population, may serve as potential additional extra-palmar reservoirs that undergo endothelial-to-mesenchymal transition, eventually giving rise to the aberrant myofibroblasts. Further studies examining the relative roles of these stem cells and the precise regulatory pathways that govern them may lead to novel therapy that targets these populations.
Preference-based Glaucoma-specific Health-related Quality of Life Instrument: Development of the Health Utility for Glaucoma
Authors: Muratov Sergei , Podbielski Dominik W. , Kennedy Kevin , Jack Susan M. , Pemberton Julia , Ahmed Iqbal I.K. , Baltaziak Monika , Xie Feng
Published: May 2018

Purpose:

To develop a descriptive system for a glaucoma-specific preference-based health-related quality of life (HRQoL) instrument: the Health Utility for Glaucoma (HUG-5).

Methods:

The descriptive system was developed in 2 stages: item identification and item selection. A systematic literature review of HRQoL assessment of glaucoma was conducted using a comprehensive search strategy. Purposeful sampling was used to recruit patients with different clinical characteristics. Relevant items were presented to glaucoma patients through face-to-face, semistructured interviews. Framework methodology was applied to analyze interview content. The recurring themes identified through an iterative content analysis represented topics of most importance and relevance to patients. These themes formed the domains of the HUG-5 descriptive system. Three versions of the descriptive system, differing in explanatory detail, were pilot tested using a focus group.

Results:

The literature review identified 19 articles which contained 266 items. These items were included for the full-text review and were used to develop an interview guide. From 12 patient interviews, 22 themes were identified and grouped into 5 domains that informed the 5 questions of the descriptive system. The HUG-5 measures visual discomfort, mobility, daily life activities, emotional well-being, and social activities. Each question has 5 response levels that range from “no problem” to “severe problem.” The focus group comprised 7 additional patients unanimously preferred the version that contained detailed, specific examples to support each question.

Conclusions:

A 5-domain descriptive system of a glaucoma-specific preference-based instrument, the HUG-5, was developed and remains to be evaluated for validity and reliability in the glaucoma patient population.
Influence of Removing the Large Retinal Vessels–related Effect on Peripapillary Vessel Density Progression Analysis in Glaucoma
Authors: Holló Gábor
Published: May 2018

Purpose:

To investigate the usefulness of removing the large vessel–related information from peripapillary optical coherence tomography angiography progression analysis. Peripapillary vessel density (VD) image series which had shown no progression with an earlier software version that did not separate capillary and large vessel–related effects were reevaluated for selective peripapillary capillary VD progression.

Materials and Methods:

Prospective retinal nerve fiber layer thickness and peripapillary VD measurements were made using the Angiovue/RTvue-XR OCT on 1 eye of 9 normal, 20 under treatment ocular hypertensive, and 24 under treatment open-angle glaucoma patients at 6-month intervals for 2 years (5 visits). In the current investigation the previously analyzed images were reanalyzed. Linear regression analysis for capillary VD progression in the radial peripapillary capillaries layer of the superior and inferior peripapillary hemifields, respectively, was made using the instrument’s new software (version 2017.1, Phase 7 update).

Results:

A statistically significant negative capillary VD slope was found in 4 glaucoma eyes. Two eyes progressed in both hemifields, and 2 eyes in 1 hemifield. The rate of statistically significant progression ranged between −1.3% and−3.2% per year. In 2 eyes the spatially corresponding hemifield retinal nerve fiber layer thickness progression was also significant (−1.4 μm/y and −1.8 μm/y). No normal and ocular hypertensive eyes showed significant capillary VD progression.

Conclusions:

In this 2-year prospective study no eye showed progression for peripapillary VD when all vessel-related information was used. In contrast, software-provided removal of the large retinal vessels–related information resulted in detection of significant capillary VD progression in 17% of the glaucoma eyes.
Exposure–Response Analysis of Micafungin in Neonatal Candidiasis
Authors: Kovanda Laura L. , Walsh Thomas J. , Benjamin Daniel K. , Arrieta Antonio , Kaufman David A. , Smith P. Brian , Manzoni Paolo , Desai Amit V. , Kaibara Atsunori , Bonate Peter L. , Hope William W.
Published: May 2018

Background:

Neonatal candidiasis causes significant morbidity and mortality in high risk infants. The micafungin dosage regimen of 10 mg/kg established for the treatment of neonatal candidiasis is based on a laboratory animal model of neonatal hematogenous Candida meningoencephalitis and pharmacokinetic (PK)–pharmacodynamic (PD) bridging studies. However, little is known about the how these PK–PD data translate clinically.

Methods:

Micafungin plasma concentrations from infants were used to construct a population PK model using Pmetrics software. Bayesian posterior estimates for infants with invasive candidiasis were used to evaluate the relationship between drug exposure and mycologic response using logistic regression.

Results:

Sixty-four infants 3–119 days of age were included, of which 29 (45%) infants had invasive candidiasis. A 2-compartment PK model fits the data well. Allometric scaling was applied to clearance and volume normalized to the mean population weight (kg). The mean (standard deviation) estimates for clearance and volume in the central compartment were 0.07 (0.05) L/h/1.8 kg and 0.61 (0.53) L/1.8 kg, respectively. No relationship between average daily area under concentration–time curve or average daily area under concentration–time curve:minimum inhibitory concentration ratio and mycologic response was demonstrated (P > 0.05). Although not statistically significant, mycologic response was numerically higher when area under concentration–time curves were at or above the PD target.

Conclusions:

While a significant exposure–response relationship was not found, PK–PD experiments support higher exposures of micafungin in infants with invasive candidiasis. More patients would clarify this relationship; however, low incidence deters the feasibility of these studies.
On King Saul, Two Missing Mules, and Kingella kingae: The Serendipitous Discovery of a Pediatric Pathogen
Authors: Yagupsky Pablo , Dagan Ron
Published: May 2018

For the first 2 decades following Kingella kingae’s initial characterization, this fastidious organism was considered an unusual cause of human infection until a study published in 1992 reported that inoculation of synovial fluid aspirates into blood culture vials improved the recovery of the bacterium. The authors of the original publication report herein the history of the discovery and review the progress made in the research of the organism.
Moisturization
Authors: Cadavona John Jay P. , Rimtepathip Parin P. , Jacob Sharon E.
Published: May 2018

Dry skin, or xerosis, is one of the most common skin conditions for which patients seek medical advice. This article summarizes the importance of maintaining moisture in the skin and discusses the biological mechanisms for moisture preservation and the functional components present in topical moisturizers.
Robotic Bronchoscopy for Diagnosis of Suspected Lung Cancer
Authors: Rojas-Solano José R. , Ugalde-Gamboa Luis , Machuzak Michael
Published: May 2018

Background:

Robotic bronchoscopy may offer alternative approaches to address limitations of current bronchoscopic techniques for biopsy of suspected peripheral lung lesions. This study sought to evaluate complications and feasibility of robotic bronchoscopy performed with the Robotic Endoscopy System (RES).

Methods:

Adult patients from a single institution underwent bronchoscopy of suspected lesions with a bronchus sign with the RES. The primary outcome was complication rate, as assessed by the incidence of related serious adverse events (SAE). The secondary outcome was technical feasibility. Data are presented as median (range), counts, and percentage. P-value was calculated using the Mann-Whitney U test.

Results:

Of 17 screened patients, 15 were eligible. The median age was 67 (38 to 79) years. The lesions (12 peripheral and 3 central) were located in the right lower lobe (33%), right upper lobe (27%), left upper lobe (27%), and left lower lobe (13%). No SAE, including pneumothorax and significant bleeding, occurred. Biopsy samples were obtained from 93% of patients. One sampling (right upper lobe) required conventional bronchoscopy and another required surgery to confirm malignancy. Cancer was confirmed in 60% (9/15) of patients. Benign features were found in 5 of 6 patients. Time to biopsy location reduced from 45 (21 to 84) minutes (first 5 cases) to 20 (7 to 47) minutes (last 9 cases), P=0.039.

Conclusions:

The study results and absence of SAE support feasibility of the RES in accessing the periphery of the lung. The RES has potential to address challenges associated with biopsy of peripheral lung lesions.