bluuebunny/crossref_metadata_2025 huggingface dataset:
Controlling the spatio-temporal dose distribution during STEM imaging by subsampled acquisition: In-situ observations of kinetic processes in liquids
Authors: Mehdi B. L. , Stevens A. , Kovarik L. , Jiang N. , Mehta H. , Liyu A. , Reehl S. , Stanfill B. , Luzi L. , Hao W. , Bramer L. , Browning N. D.
Published: August 2019

Subsampled image acquisition followed by image inpainting in a scanning transmission electron microscope is a novel approach to control dose and increase the image frame rate during experiments, thereby allowing independent control of the spatial and temporal dose envelope during image acquisition. Here, subsampled imaging is shown to permit precise in situ observations of the fundamental kinetic processes behind nucleation and growth of silver (Ag) nanoparticles from an aqueous solution. At high sampling-levels, nanoparticles can be observed with morphologies that are consistent with strong interface interactions, i.e., rafts and pillars, whereas at low sampling-levels, the particles exhibit regular spherical morphologies. The relative numbers of rafts/pillars and regular nanoparticles, their sizes, and their incubation times can be attributed to local changes in the molar concentration of the Ag ions in the aqueous solution; higher sampling-levels significantly increase the reactants in the vicinity of the window, leading to rapid supersaturation and the precipitation on the window surface. These precisely controlled kinetics highlight subsampled imaging as a method by which the driving force for nucleation and growth (i.e., the electron beam) can be disentangled from the spatial/temporal resolution of the observation in all in situ experiments, providing a pathway to identify and quantify the importance of individual kinetic factors behind nucleation and growth in a wide variety of complex materials systems and architectures.
New variable-order fractional chaotic systems for fast image encryption
Authors: Wu Guo-Cheng , Deng Zhen-Guo , Baleanu Dumitru , Zeng De-Qiang
Published: August 2019

New variable-order fractional chaotic systems are proposed in this paper. A concept of short memory is introduced where the initial point in the Caputo derivative is varied. The fractional order is defined by the use of a piecewise constant function which leads to rich chaotic dynamics. The predictor–corrector method is adopted, and numerical solutions of fractional delay equations are obtained. Then, this concept is extended to fractional difference equations, and generalized chaotic behaviors are discussed numerically. Finally, the new fractional chaotic models are applied to block image encryption and each block has a different fractional order. The new chaotic system improves security of the image encryption and saves the encryption time greatly.
Triplet harvesting in the polaritonic regime: A variational polaron approach
Authors: Martínez-Martínez Luis A. , Eizner Elad , Kéna-Cohen Stéphane , Yuen-Zhou Joel
Published: August 2019

We explore the electroluminescence efficiency for a quantum mechanical model of a large number of molecular emitters embedded in an optical microcavity. We characterize the circumstances under which a microcavity enhances harvesting of triplet excitons via reverse intersystem-crossing (R-ISC) into singlet populations that can emit light. For that end, we develop a time-local master equation in a variationally optimized frame, which allows for the exploration of the population dynamics of chemically relevant species in different regimes of emitter coupling to the condensed phase vibrational bath and to the microcavity photonic mode. For a vibrational bath that equilibrates faster than R-ISC (in emitters with weak singlet-triplet mixing), our results reveal that significant improvements in efficiencies with respect to the cavity-free counterpart can be obtained for strong coupling of the singlet exciton to a photonic mode, as long as the singlet to triplet exciton transition is within the inverted Marcus regime; under these circumstances, the activation energy barrier from the triplet to the lower polariton can be greatly reduced with respect to that from the triplet to the singlet exciton, thus overcoming the detrimental delocalization of the polariton states across a macroscopic number of molecules. On the other hand, for a vibrational bath that equilibrates slower than R-ISC (i.e., emitters with strong singlet-triplet mixing), we find that while enhancements in photoluminescence can be obtained via vibrational relaxation into polaritons, this only occurs for a small number of emitters coupled to the photon mode, with delocalization of the polaritons across many emitters eventually being detrimental to electroluminescence efficiency. These findings provide insight into the tunability of optoelectronic processes in molecular materials due to weak and strong light-matter coupling.
Path-integral dynamics of water using curvilinear centroids
Authors: Trenins George , Willatt Michael J. , Althorpe Stuart C.
Published: August 2019

We develop a path-integral dynamics method for water that resembles centroid molecular dynamics (CMD), except that the centroids are averages of curvilinear, rather than Cartesian, bead coordinates. The curvilinear coordinates are used explicitly only when computing the potential of mean force, the components of which are re-expressed in terms of Cartesian “quasicentroids” (so-called because they are close to the Cartesian centroids). Cartesian equations of motion are obtained by making small approximations to the quantum Boltzmann distribution. Simulations of the infrared spectra of various water models over 150–600 K show these approximations to be justified: for a two-dimensional OH-bond model, the quasicentroid molecular dynamics (QCMD) spectra lie close to the exact quantum spectra, and almost on top of the Matsubara dynamics spectra; for gas-phase water, the QCMD spectra are close to the exact quantum spectra; for liquid water and ice (using the q-TIP4P/F surface), the QCMD spectra are close to the CMD spectra at 600 K and line up with the results of thermostated ring-polymer molecular dynamics and approximate quantum calculations at 300 and 150 K. The QCMD spectra show no sign of the CMD “curvature problem” (of erroneous red shifts and broadening). In the liquid and ice simulations, the potential of mean force was evaluated on-the-fly by generalizing an adiabatic CMD algorithm to curvilinear coordinates; the full limit of adiabatic separation needed to be taken, which made the QCMD calculations 8 times more expensive than partially adiabatic CMD at 300 K, and 32 times at 150 K (and the intensities may still not be converged at this temperature). The QCMD method is probably generalizable to many other systems, provided that collective bead-coordinates can be identified that yield compact mean-field ring-polymer distributions.
High energy storage performance in lead-free BiFeO3-BaTiO3 ferroelectric thin film fabricated by pulsed laser deposition
Authors: Hu Yuqing , Xie Qingxiu , Liang Ruihong , Zhao Xiangyong , Zhou Zhiyong , Dong Xianlin , Wang Feifei , Tang Yanxue , Liu Ningtao , Liu Xing
Published: August 2019

In this work, the 0.68BiFeO3-0.32BaTiO3 (BFBT) ferroelectric thin film was fabricated with high maximum polarization for energy storage applications. BFBT thin film with pure perovskite phase was deposited on Pt/Ti/SiO2/Si substrates at 600°C by Pulsed Laser Deposition (PLD) method. We measured the ferroelectric hysteresis, dielectric properties and the fatigue performance of the BFBT thin film with thickness of about 200 nm. It was found that the film has a high maximum field-induced polarization value of 86 μC/cm2. Under an applied low electric field of 900 kV/cm, the recoverable energy density (Ure) could reach up to 19 J/cm3, and the energy efficiency (η) is around 51% at room temperature. Furthermore, the film shows outstanding fatigue endurance even after 1×107 cycles. All results suggest that lead-free BFBT ferroelectric thin film is very promising energy storage materials.
Vibronic fingerprint of singlet fission in hexacene
Authors: Deng Gang-Hua , Wei Qianshun , Han Jian , Qian Yuqin , Luo Jun , Harutyunyan Avetik R. , Chen Gugang , Bian Hongtao , Chen Hanning , Rao Yi
Published: August 2019

Singlet fission has the great potential to overcome the Shockley–Queisser thermodynamic limit and thus promotes solar power conversion efficiency. However, the current limited understandings of detailed singlet fission mechanisms hinder a further improved design of versatile singlet fission materials. In the present study, we combined ultrafast transient infrared spectroscopy with ab initio calculations to elucidate the roles played by the vibrational normal modes in the process of singlet fission for hexacene. Our transient infrared experiments revealed three groups of vibrational modes that are prominent in vibronic coupling upon photoexcitation. Through our computational study, those normal modes with notable Franck-Condon shifts have been classified as ring-twisting modes near 1300.0 cm−1, ring-stretching modes near 1600.0 cm−1, and ring-scissoring modes near 1700.0 cm−1. Experimentally, a ring-stretching mode near 1620.0 cm−1 exhibits a significant blue-shift of 4.0 cm−1 during singlet fission, which reaction rate turns out to be 0.59 ± 0.07 ps. More interestingly, the blue-shifted mode was also identified by our functional mode singlet fission theory as the primary driving mode for singlet fission, suggesting the importance of vibronic coupling when a correlated triplet pair of hexacene is directly converted from its first excited state singlet exciton. Our findings indicate that the ultrafast transient infrared spectroscopy, in conjunction with the nonadiabatic transition theory, is a powerful tool to probe the vibronic fingerprint of singlet fission.
Relaxation dynamics in supercooled oligomer liquids: From shear-stress fluctuations to shear modulus and structural correlations
Authors: Klochko L. , Baschnagel J. , Wittmer J. P. , Semenov A. N.
Published: August 2019

Static and dynamical properties of a model glass-forming oligomer liquid are analyzed using molecular dynamics simulations. The temperature and system size effects are assessed for the affine shear modulus μA, the quasistatic shear modulus μsf (obtained using the stress-fluctuation relation), and the shear relaxation modulus G(t). It is found that while both μA and μsf are nearly independent of the system size, their variances show significant system size dependence, in particular, below the glass transition temperature Tg. It is also shown that the standard deviation of the shear modulus, δμsf(T), exhibits a pronounced peak at T ≈ Tg whose position is nearly independent of the system volume V. Moreover, the whole function δμsf(T) is nearly the same for different system sizes above the glass transition. We propose a theory which quantitatively predicts δμsf(T) at T ≳ Tg and explains both its independence of V and its peak near Tg. It is also established that below Tg the variance of the affine modulus follows the standard power law, δμA2∝1/V, while δμsf shows anomalously a slow decrease with V as δμsf2∝1/Vα with α < 1. On this basis, it is argued that the studied glass-forming systems must show long-range structural correlations in the amorphous state.
Advances in lithium sulfur batteries pave the way for their commercial use
Authors: Johnson-Groh Mara
Published: August 2019

Studies exploring the potential of lithium sulfur batteries are summarized in a new review.
Nema and the Xenos
Authors: Wild Ailsa , Reed Aviva , Barr Briony , Crocetti Gregory , Stock S. Patricia
Published: August 2019

This is a story about tiny creatures that live in the darkness of the soil.
When a tree cries out in pain, some unexpected heroes come to the rescue. Nema and her gang of young nematodes (tiny worms) embark on a dangerous journey underground. The Xenos, a group of wise but deadly bacteria, hitch a ride. The story of how they help the tree is full of action, life-or-death challenges and microscopic warfare. It is a story of co-operation and ancient partnership, about events happening all over the Earth, in the hidden worlds beneath our feet.
Variation and change in a specialized register
Authors: Smith Nicholas , Waters Cathleen
Published: August 2019

Corpus-based studies of specialized registers typically sample texts using random methods as far as possible, but they disregard social characteristics of the speakers/writers. In contrast, in corpus-based studies of conversation and quantitative sociolinguistic studies, sampling is more typically designed to optimize social representation. To our knowledge, this study is the first to compare linguistic outcomes from random versus sociolinguistic sampling in a specialized register. Our data comes from the biographical radio chat show,Desert Island Discs(DID), at different points in time. We constructed two versions of aDIDcorpus: a sociolinguistic judgment sample based on guest demographics, and a random sample. We compare grammatical usage between them using an inductive (‘key POS-tags’) method and close manual analysis, uncovering some evidence of significant grammatical differences between the samples and differing patterns of diachronic change. We discuss the implications of our research for corpus design, representativeness and analysis in specialized registers.
Robust optical clock transitions in trapped ions using dynamical decoupling
Authors: Aharon Nati , Spethmann Nicolas , Leroux Ian D , Schmidt Piet O , Retzker Alex
Published: August 2019

We present a novel method for engineering an optical clock transition that is robust against external field fluctuations and is able to overcome limits resulting from field inhomogeneities. The technique is based on the application of continuous driving fields to form a pair of dressed states essentially free of all relevant shifts. Specifically, the clock transition is robust to magnetic field shifts, quadrupole and other tensor shifts, and amplitude fluctuations of the driving fields. The scheme is applicable to either a single ion or an ensemble of ions, and is relevant for several types of ions, such as

40

Ca

+

,

88

Sr

+

,

138

Ba

+

and

176

Lu

+

. Taking a spherically symmetric Coulomb crystal formed by 400

40

Ca

+

ions as an example, we show through numerical simulations that the inhomogeneous linewidth of tens of Hertz in such a crystal together with linear Zeeman shifts of order 10 MHz are reduced to form a linewidth of around 1 Hz. We estimate a two-order-of-magnitude reduction in averaging time compared to state-of-the art single ion frequency references, assuming a probe laser fractional instability of

10

−
15

. Furthermore, a statistical uncertainty reaching 2.9 × 10−16 in 1 s is estimated for a cascaded clock scheme in which the dynamically decoupled Coulomb crystal clock stabilizes the interrogation laser for an

27

Al

+

clock.
Physical activity in hospitalised older people: the feasibility and acceptability of a volunteer-led mobility intervention in the SoMoVe™ study
Authors: Lim Stephen , Ibrahim Kinda , Dodds Richard , Purkis Annette , Baxter Mark , Rogers Anne , Sayer Avan Aihie , Roberts Helen C
Published: August 2019

Objectives

to determine the feasibility and acceptability of a volunteer-led mobility intervention to improve activity levels of older inpatients.

Design

pre-post mixed methods study.

Setting

acute medical wards for older people.

Participants

one hundred inpatients aged ≥70 years who were mobile prior to hospitalisation: 50 participants were recruited before and 50 after the intervention was established. Twenty-five participants (patients, nurses, therapists and volunteers) were interviewed to determine the acceptability of the intervention.

Interventions

twice daily volunteer-led mobility and bedside exercises.

Main outcome measures

the feasibility of delivering a volunteer-led mobility intervention, including the recruitment, training and retention of volunteers and the acceptability of the intervention to patients and healthcare professionals. Secondary outcome measures included objectively measured daily step count, length of stay, 30-day readmission and any adverse events.

Results

seventeen volunteers were recruited, 16 completed training and 12 were retained. Fifty participants (mean age 86 years) received the intervention, with a median daily step count of 912 steps (interquartile range [IQR] 295–1824) compared to the baseline group (n = 50, mean age 87 years) of 636 steps (IQR 298–1468). No adverse events were reported. The intervention was acceptable to patients and staff. Facilitating factors of the intervention included the social aspect of the intervention and perceived benefits by stakeholders. Barriers identified included the busy clinical environment and lack of awareness of the intervention among staff.

Conclusions

it was feasible to deliver a volunteer-led mobility intervention including the recruitment, training and retention of volunteers. The intervention was safe and acceptable to healthcare professionals and patients.
Synapsin I Synchronizes GABA Release in Distinct Interneuron Subpopulations
Authors: Forte N , Binda F , Contestabile A , Benfenati F , Baldelli P
Published: August 2019

Neurotransmitters can be released either synchronously or asynchronously with respect to action potential timing. Synapsins (Syns) are a family of synaptic vesicle (SV) phosphoproteins that assist gamma-aminobutyric acid (GABA) release and allow a physiological excitation/inhibition balance. Consistently, deletion of either or both Syn1 and Syn2 genes is epileptogenic. In this work, we have characterized the effect of SynI knockout (KO) in the regulation of GABA release dynamics. Using patch-clamp recordings in hippocampal slices, we demonstrate that the lack of SynI impairs synchronous GABA release via a reduction of the readily releasable SVs and, in parallel, increases asynchronous GABA release. The effects of SynI deletion on synchronous GABA release were occluded by ω-AgatoxinIVA, indicating the involvement of P/Q-type Ca2+channel-expressing neurons. Using in situ hybridization, we show that SynI is more expressed in parvalbumin (PV) interneurons, characterized by synchronous release, than in cholecystokinin or SOM interneurons, characterized by a more asynchronous release. Optogenetic activation of PV and SOM interneurons revealed a specific reduction of synchronous release in PV/SynIKO interneurons associated with an increased asynchronous release in SOM/SynIKO interneurons. The results demonstrate that SynI is differentially expressed in interneuron subpopulations, where it boosts synchronous and limits asynchronous GABA release.
Development and Implementation of Multiplex TaqMan Array Cards for Specimen Testing at Child Health and Mortality Prevention Surveillance Site Laboratories
Authors: Diaz Maureen H , Waller Jessica L , Theodore M Jordan , Patel Nishi , Wolff Bernard J , Benitez Alvaro J , Morris Timothy , Raghunathan Pratima L , Breiman Robert F , Whitney Cynthia G , Blau Dianna M , Winchell Jonas M
Published: August 2019

Child Health and Mortality Prevention Surveillance (CHAMPS) laboratories are employing a variety of laboratory methods to identify infectious agents contributing to deaths of children <5 years old and stillbirths in sub-Saharan Africa and South Asia. In support of this long-term objective, our team developed TaqMan Array Cards (TACs) for testing postmortem specimens (blood, cerebrospinal fluid, lung tissue, respiratory tract swabs, and rectal swabs) for >100 real-time polymerase chain reaction (PCR) targets in total (30–45 per card depending on configuration). Multipathogen panels were configured by syndrome and customized to include pathogens of significance in young children within the regions where CHAMPS is conducted, including bacteria (57 targets covering 30 genera), viruses (48 targets covering 40 viruses), parasites (8 targets covering 8 organisms), and fungi (3 targets covering 3 organisms). The development and application of multiplex real-time PCR reactions to the TAC microfluidic platform increased the number of targets in each panel while maintaining assay efficiency and replicates for heightened sensitivity. These advances represent a substantial improvement in the utility of this technology for infectious disease diagnostics and surveillance. We optimized all aspects of the CHAMPS molecular laboratory testing workflow including nucleic acid extraction, quality assurance, and data management to ensure comprehensive molecular testing of specimens and high-quality data. Here we describe the development and implementation of multiplex TACs and associated laboratory protocols for specimen processing, testing, and data management at CHAMPS site laboratories.
Dynamics of Submicroscopic Plasmodium falciparum Infections Throughout Pregnancy: A Preconception Cohort Study in Benin
Authors: Hounkonnou Cornélia P A , Briand Valérie , Fievet Nadine , Accrombessi Manfred , Yovo Emmanuel , Mama Atikatou , Sossou Darius , Vianou Bertin , Massougbodji Achille , Ndam Nicaise Tuikue , Cot Michel , Cottrell Gilles
Published: August 2019

Background

In the context of global malaria elimination efforts, special attention is being paid to submicroscopic Plasmodium falciparum infections. In pregnant, sub-Saharan African women, such infections are more prevalent than microscopic infections, and are thought to have adverse effects on both mothers’ and newborns’ health. However, no study has studied the dynamics and determinants of these infections throughout pregnancy. Retard de Croissance Intra-uterin et Paludisme (RECIPAL), a preconception cohort study carried out in Benin between 2014 and 2017, represented a unique opportunity to assess this issue.

Methods

We used data from 273 pregnant Beninese women who were followed-up from preconception to delivery. We studied the dynamics of and factors influencing submicroscopic (and microscopic) P. falciparum infections during the 3 trimesters of pregnancy, using an ordinal logistic mixed model.

Results

The incidence rate of submicroscopic P. falciparum infections during pregnancy was 12.7 per 100 person-months (95% confidence interval [CI] 10.8–14.9), compared to 6.7 per 100 person-months (95% CI 5.5–8.1) for microscopic infections. The prevalences were highest in the first trimester for both submicroscopic and microscopic infections. After adjustment for potential confounding factors, we found that those of young age and those with a submicroscopic P. falciparum infection prior to pregnancy were at significantly higher risks of submicroscopic and microscopic infections throughout pregnancy, with a more pronounced effect in the first trimester of pregnancy.

Conclusions

The first trimester of pregnancy is a particularly high-risk period for P. falciparum infection during pregnancy, especially for the youngest women. Malaria prevention tools covering the preconception period and early pregnancy are urgently needed to better protect pregnant women and their newborns.
Likely oscillatory motions of stochastic hyperelastic solids
Authors: Mihai L Angela , Fitt Danielle , Woolley Thomas E , Goriely Alain
Published: August 2019

Stochastic homogeneous hyperelastic solids are characterized by strain-energy densities where the parameters are random variables defined by probability density functions. These models allow for the propagation of uncertainties from input data to output quantities of interest. To investigate the effect of probabilistic parameters on predicted mechanical responses, we study radial oscillations of cylindrical and spherical shells of stochastic incompressible isotropic hyperelastic material, formulated as quasi-equilibrated motions where the system is in equilibrium at every time instant. Additionally, we study finite shear oscillations of a cuboid, which are not quasi-equilibrated. We find that, for hyperelastic bodies of stochastic neo-Hookean or Mooney–Rivlin material, the amplitude and period of the oscillations follow probability distributions that can be characterized. Further, for cylindrical tubes and spherical shells, when an impulse surface traction is applied, there is a parameter interval where the oscillatory and non-oscillatory motions compete, in the sense that both have a chance to occur with a given probability. We refer to the dynamic evolution of these elastic systems, which exhibit inherent uncertainties due to the material properties, as ‘likely oscillatory motions’.
Testing for the Diffusion Matrix in a Continuous-Time Markov Process Model with Applications to the Term Structure of Interest Rates
Authors: Li Fuchun
Published: August 2019

For each component in the diffusion matrix of a d-dimensional diffusion process, we propose a test for the parametric specification of this component. Overall, d(d−1)/2 test statistics are constructed for the off-diagonal components, while d test statistics being for the main diagonal components. Using theories of degenerate U-statistics, each of all these test statistics is shown to follow an asymptotic standard normal distribution under null hypothesis, while diverging to infinity if the component is misspecified over a significant range. We obtain new empirical findings by applying our tests to evaluate a variety of three-factor affine term structure models in modeling the volatility dynamics of monthly U.S. Treasury yields.
The Asymmetric Judicial Dialogue Between the ICJ and the IACtHR: An Empirical Analysis
Authors: Almeida Paula Wojcikiewicz
Published: August 2019

This article evaluates the judicial dialogue between the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR). It aims to discuss, on the one hand, the use of the ICJ jurisprudence in the case law of the Inter-American Court and the use of the IACtHR jurisprudence in the case law of the ICJ, on the other hand. Being aware that the ICJ and the IACtHR are placed in different levels and possess structural differences, the judicial dialogue between these two courts is inevitably marked by asymmetries. The empirical analysis of the interaction between the ICJ and the IACtHR aims to identify the functions of the judicial dialogue, which encompass the general cross-fertilization function and the function of enhancing the persuasiveness, authority or legitimacy of individual judicial decisions.
Does Tranexamic Acid Increase the Incidence of Thromboembolism After Spinal Fusion Surgery?
Authors: Ko Bong-Seong , Cho Kyu-Jung , Kim Young-Tae , Park Jae-Woo , Kim Nak-Chul
Published: August 2019

Study Design:

This was a retrospective analysis of prospectively collected data.

Objective:

To investigate the incidence of thromboembolism in patients who received tranexamic acid (TXA) after lumbar spine fusion and determine the diagnostic value of lower limb duplex sonography as a screening test.

Summary of Background Data:

TXA is effective in reducing blood drainage in spine fusion surgery but some studies have reported increased incidence of venous thromboembolism associated with TXA.

Materials and Methods:

One hundred twenty-two patients who underwent lumbar fusion for degenerative spinal disease received intravenous TXA in doses equivalent to 10 mg/kg for 48 hours after surgery. As a control group, 85 patients received intravenous administration of the same amount of normal saline. D-dimer levels were checked on the day of admission and the seventh postoperative day (POD#7). All patients underwent duplex sonography on POD#7, and patients with abnormal results were further evaluated with computed tomography angiography and pulmonary arterial angiography.

Results:

None of the patients showed symptoms of deep vein thrombosis (DVT). Suspicious signs of DVT were observed in 5 patients in the TXA group and 4 patients in the control group in lower limb duplex sonography. Finally, DVT was confirmed by computed tomography angiography in one of 122 patients (0.8%) in the TXA group and in one of 85 patients (1.2%) in the control group. D-dimer levels on POD#7 were higher in the patients with DVT than in patients without DVT. Average postoperative blood drain was 421.3±133.1 mL in the TXA group and 635.2±151.2 mL in the control group (P<0.001), which showed TXA was effective to reduce postoperative hemorrhage.

Conclusions:

The incidence of thromboembolism after using TXA in lumbar fusion surgery was 0.8%, as comparable as the incidence of thromboembolism in the control group. Lower limb duplex sonography is not recommended for screening test of DVT because of high false-positive rate.

Level of Evidence:

Level III.
Potential Role of Paraspinal Musculature in the Maintenance of Spinopelvic Alignment in Patients With Adult Spinal Deformities
Authors: Katsu Marina , Ohba Tetsuro , Ebata Shigeto , Oba Hiroki , Koyama Kensuke , Haro Hirotaka
Published: August 2019

Study Design:

A retrospective observational study.

Objectives:

To (1) compare skeletal muscle mass index (SMI) and the composition of paraspinal muscles between patients with lumbar spinal stenosis (LSS) and adult spinal deformity (ASD) who underwent spinal surgery, (2) determine whether paraspinal muscles influence low back pain in ASD, and (3) ascertain which radiographic spinal parameters of ASD are predominantly influenced by paraspinal muscles.

Summary of Background Data:

Relative muscle cross-sectional area (rmCSA; total CSA minus intramuscular fat CSA) determined using magnetic resonance imaging (MRI) is useful when evaluating not only muscle volume but also muscle quality. Currently, no study has examined paraspinal muscles using rmCSAs to determine which radiographic spinopelvic parameters identified in patients with severe spinal deformities make them candidates for thoracolumbar corrective surgery.

Materials and Methods:

Paraspinal muscle rmCSAs were calculated using preoperative T2-weighted MRIs at the L3/4 axial level. Whole-body bone mineral density and lean, soft tissue mass were measured using dual-energy x-ray absorptiometry. SMI was calculated as appendicular (upper and lower limbs) lean, soft tissue mass (kg/m2). Correlations between low back pain according to the Roland-Morris Disability Questionnaire, Oswestry Disability Index, spinopelvic parameters, and rmCSA were evaluated for 110 consecutive patients with ASD and 50 consecutive patients with LSS who underwent spinal surgery.

Results:

There was no significant difference in the total SMI and morbidity rate of sarcopenia between patients with ASD and LSS. A significant negative correlation between Oswestry Disability Index and the rmCSA of the multifidus muscles and the rmCSA of the erector muscles were observed. There was a significant positive correlation between pelvic tilt/sacral slope and multifidus/erector muscles.

Conclusions:

Paraspinal muscles evaluated with MRI were more significantly associated with the pathology of ASD compared with appendicular skeletal muscle evaluations with dual-energy x-ray absorptiometry. The present study indicates that multifidus and erector muscles significantly influenced the maintenance of the pelvic alignment.

Level of Evidence:

Level III.
A Multicenter Comparison of Reconstruction Strategies after Wide Excision for Severe Axillary Hidradenitis Suppurativa
Authors: Ovadja Zachri N. , Bartelink Sophieke A.W. , van de Kar Annekatrien L. , van der Horst Chantal M.A.M. , Lapid Oren
Published: August 2019

Background:

An appropriate reconstruction strategy after wide excision for severe cases of axillary hidradenitis suppurativa (HS) is important to optimize outcomes, but no consensus exists on which reconstruction strategy should be preferred.

Objective:

Evaluate which reconstruction strategy after wide excision in patients with severe axillary HS is associated with improved outcomes in terms of recurrence rate, complications, post-reconstruction limb function, aesthetics, and patient satisfaction.

Methods:

Retrospective analysis between 2008 and 2018 of wide excision and reconstruction by primary closure (PC), secondary intention healing (SIH), split thickness skin grafts (STSG), or fasciocutaneous flaps (FCF). The primary endpoint was the rate of recurrence during follow-up.

Results:

A total of 107 surgical interventions were performed on 54 patients. The overall recurrence rate was 31.8% after a median follow-up of 30 months, with a significant difference between PC (48%), SIH (16%), STSG (29%), and FCF (10%) (P = 0.03). Surgical complications requiring reoperation occurred in 2% after PC, 0% after SIH, 13% after STSG, and 15% after FCF (P = 0.11). The median score regarding function, aesthetics, and satisfaction after all interventions was 17 out of 20 points, but the score was lower after FCF than PC, SIH, and STSG (P = 0.03).

Conclusions:

Reconstruction by PC should be reserved for patients with limited HS lesions, whereas FCF was most effective in avoiding recurrence, but was associated with unfavorable short-term results and patient-reported outcomes regarding function and aesthetics. FCF should generally be reserved for patients with recurrent, severe HS comprising an extensive surface of the axillary skin.
Treatment Attitudes and Adherence Among Patients with Bipolar Disorder: A Systematic Review of Quantitative and Qualitative Studies
Authors: Chakrabarti Subho
Published: August 2019

Background

Systematic reviews about treatment attitudes of patients influencing adherence in bipolar disorder (BD) are rare.

Methods

A systematic review was conducted according to the PRISMA guidelines and principles of thematic synthesis. Selectively identified quantitative and qualitative studies were used to examine the attitude-adherence relationship in BD, the types and correlates of treatment attitudes, and the impact of psychosocial interventions on attitudes.

Results

The final list of 163 articles included 114 observational reports (incorporating 21 psychosocial intervention trials), 45 qualitative/descriptive studies, and 4 patient surveys. A positive association between treatment attitudes and adherence was found in most quantitative and qualitative studies, though the strength of the relationship was unclear. Thematic analysis of qualitative studies suggested that patient attitudes influencing adherence were based on perceived advantages and disadvantages of treatment. The principal correlates of patients’ attitudes were family attitudes, the clinician-patient alliance, social support, and patients’ knowledge of BD. Though negative attitudes such as denial, concerns about adverse treatment consequences, and stigmatizing effects of treatment were common, many patients believed treatment to be beneficial and necessary. The limited data on the effect of psychosocial interventions indicated that treatments selectively targeting attitudes enhanced adherence.

Limitations

The studies were heterogeneous in design; the quality was uneven (fair to poor); and the risk of bias moderate to high.

Conclusions

Despite these flaws, awareness of the existing evidence on the attitude-adherence association and other aspects of treatment attitudes in BD can help in efforts to address nonadherence in BD.
Surgical Outcomes of Prolene Gonioscopy-assisted Transluminal Trabeculotomy in Patients With Moderate to Advanced Open-Angle Glaucoma
Authors: Aktas Zeynep , Ucgul Ahmet Y. , Bektas Caglar , Sahin Karamert Selin
Published: August 2019

Précis:

The present study demonstrates that surgical success rate of gonioscopy-assisted transluminal trabeculotomy (GATT) is 83.7% according to target intraocular pressure (IOP) ≤21 mm Hg and ≥20% reduction from baseline in patients with moderate to advanced glaucoma, with an average follow-up of 19.4 months.

Purpose:

The aim of the study was to assess the outcomes of GATT in eyes with moderate to advanced open-angle glaucoma.

Patients and Methods:

A retrospective study included 104 eyes of 104 patients, with a mean age of 58.9±18.5 (15 to 87) years, who underwent GATT using the 6/0 prolene suture to treat open-angle glaucoma. The GATT procedure was carried out alone or in combination with phacoemulsification. IOP at baseline, third, sixth, ninth, 12th, and 18th months of follow-up; need of antiglaucoma medication; need of further glaucoma surgery; cup/disc ratio; and best-corrected visual acuity (BCVA) were recorded. Patients with prior incisional glaucoma surgery were excluded. Surgical success was determined for both IOP <21 and <18 mm Hg and also ≥20% reduction from baseline without further glaucoma surgery.

Results:

A total of 65 patients with primary open-angle glaucoma (POAG) and 39 patients with secondary open-angle glaucoma (SOAG), including pseudoexfoliative, pigmentary, uveitic, and steroid-induced glaucoma underwent GATT. Preoperative mean IOP was 25.0±7.3 mm Hg. Preoperative average number of antiglaucoma medications was 3.4±0.6. The average follow-up time was 19.4±8.1 (6 to 37) months. Preoperative average BCVA was 0.51±0.24, and cup/disc ratio was 0.85±0.14. Surgical success was achieved in 87 of 104 (83.7%). Seven patients had medically uncontrolled glaucoma after GATT surgery, and they underwent further surgery. Patients with POAG had a higher percentage of IOP reduction than patients with SOAG at 18th month of follow-up (40.1% vs. 27.6%). Need for medication at final visit was similar between POAG and SOAG.

Conclusion:

GATT procedure is a safe and successful option for the treatment of moderate to advanced open-angle glaucoma. Surgical success could be maintained up to ∼18 months.
Older Drivers and Glaucoma in India: Driving Habits and Crash Risks
Authors: Deshmukh Ajinkya V. , Murthy Gowri J. , Reddy Ayyappa , Murthy Praveen R. , Kattige Jyothi , Murthy Vinay R.
Published: August 2019

Précis:

In India, older drivers with glaucoma show greater driving difficulty but are not involved in higher number of on-road accidents. To achieve balance between safety aspects and independence for drivers with glaucoma is important.

Purpose:

The purpose of this study was to analyze driving habits of patients with glaucoma and to compare their driving behavior, driving difficulties, and accident rates with nonglaucoma controls.

Patients:

Patients with glaucoma aged older than 40 years were recruited. Subjects with best-corrected visual acuity ≤6/24 in the better-seeing eye and those having primary eye disorder other than glaucoma were excluded. Age-matched nonglaucoma controls were recruited. Subjects with clinically significant cataract and/or with best-corrected visual acuity ≤6/24 in both eyes were excluded. All cases and controls were legally licensed to drive.

Materials and Methods:

In this study, Driving Habits Questionnaire was used. Collected data were statistically analyzed using SAS, version 9.2 (GLM procedure), and IBM SPSS, version 22. P-values <0.05 were considered statistically significant.

Results:

All controls and 84% (n=84/100) of cases were current drivers. Among them, 16% (n=16/100) cases had stopped driving, of which 31.25% (n=5/16) had stopped because of self-reported ocular causes. Cases drove lesser number of days per week (P=0.001) and had more driving dependence on other drivers (44%, n=37/84) compared with controls. Glaucoma was significantly associated with driving difficulty in the rain, in rush-hour traffic, and at night. Comparing driving difficulty scores and visual field index within glaucoma group showed statistical significance [F(1,82)=22.12, P<0.001]. Composite scores of driving difficulty (P<0.001) and driving space (P=0.003) between the 2 groups showed strong statistical significance. Controls had higher number of self-reported accidents (P<0.001).

Conclusions:

Patients with glaucoma show greater driving difficulty, self-regulate their driving behavior, and restrict their driving. Older patients with glaucoma in India are not involved in higher rates of on-road crash risks compared with nonglaucoma drivers.
Physician Assistant Students' Perceptions of Cultural Competence in Providing Care to Diverse Populations
Authors: Sherer Erin L. , Allegrante John P.
Published: August 2019

Purpose

To determine physician assistant (PA) students' perceived levels of preparedness to treat patients from culturally diverse backgrounds.

Methods

An online survey with quantitative and qualitative components was distributed to students at 8 PA programs in different geographic locations of the United States. The survey used a modified version of the previously validated Self-Assessment of Perceived Level of Cultural Competence Questionnaire and evaluated PA students' knowledge, skills, encounters, attitudes, awareness, and abilities regarding cultural competence, as well as students' evaluation of these components of their education. Descriptive statistics were generated using SPSS software, and qualitative findings were analyzed for common themes.

Results

PA students rated their attitudes, awareness, and abilities about cultural competence as significantly greater than their cultural knowledge, skills, and encounters. Second-year students and racial minority students reported higher personal ratings for levels of cultural competence. Most PA students reported being well prepared (39%) or moderately prepared (46%), compared to those who did not feel at all prepared (15%). Students indicated that specific classes focusing on cultural topics, discussions about cultural issues, and clinical experiences were the most useful for promoting cross-cultural education.

Conclusion

While PA students perceive cultural competence to be important, they appear to be deficient in the areas of cultural knowledge, skills, and encounters. Integrating cultural competence courses, cultural discussions, and clinical rotations involving diverse patient populations should be encouraged throughout PA training as they may strengthen students' preparedness to provide cross-cultural care.
Effect of Online Training Modules and Virtual Patients on First-Year Physician Assistant Students' Confidence Levels
Authors: Donkers Kelly , DeLong Deborah , Brown Nicole
Published: August 2019

Purpose

Pilot study assessing impact of virtual patients (VPs) and online modules on first-year physician assistant (PA) student confidence in documentation performance.

Methods

Five VP cases (head, eyes, ears, nose, and throat; musculoskeletal; abdominal; neurological; and comprehensive history and physical examination) and one module (cardiac sounds) were implemented to complement the core PA curriculum.

Results

A VP-based protocol significantly improved student confidence for taking a history, performing a physical examination, and undertaking clinical reasoning as well as providing overall documentation confidence. These 3 subscales explain nearly half (49%) of overall pretraining confidence, increasing to nearly two-thirds (63%) of overall posttraining confidence. Stepwise regression finds confidence in clinical reasoning to be the only unique predictor of overall pretraining confidence. In contrast, confidence in history taking and physical exams uniquely predicts overall posttraining confidence.

Conclusions

Virtual patient cases and online modules help improve overall and dimension-specific documentation confidence, with different dimensions driving overall confidence pre- and posttraining. Implications for job efficacy are discussed.
Redefining Rural Health: Student Perceptions After Participation in A Migrant Farmworker Clinic
Authors: Noonan Catherine , Tudini Frank , Sawyer Scot
Published: August 2019

Introduction.

Physical therapists are in short supply in rural communities, in spite of significant need for their services. To address shortages, health care education programs are advised to design rural-centric curricula to better prepare providers to practice in these settings. However, only a few published research articles have addressed curricular elements designed to prepare student physical therapists (SPTs) for practice in rural settings. This study investigates the impact of participation in a rural, agricultural mobile clinic for migrant agricultural workers on SPTs' understanding of rural communities and rural health care practice.

Methods.

Student physical therapists in 2015 (Y1), 2016 (Y2), and 2017 (Y3) cohorts completed a survey via Qualtrics (Provo, UT) soliciting their reflections on participation in the mobile clinic. Surveys consisted of 8 open-ended questions developed from current service-learning literature. Responses were coded using a thematic analysis approach by 2 authors (C.N. and F.T.), while a third author (S.S.) determined categorization if disagreement occurred. Frequency (%) of responses was calculated by determining number of individual theme responses compared to total number of coded items.

Results.

Authors identified a total of 198 coded items over all survey responses (Y1–Y3). Six themes emerged: Diversity of Rural Communities (7.76%), Nature of Agricultural Labor (9.60%), Professional Role and Responsibility (17.68%), Extent of Need (19.70%), Communication (21.21%), and Nature of Rural Practice (24.24%). Notably, even SPTs who reported rural upbringing noted changes in perception of rural communities after participation in the clinic.

Conclusions.

Student physical therapists showed increased understanding of the nature of rural health care practice, among other topics, after participation in the mobile clinic. Curricular elements that address language barrier; appreciation versus impact; and which offer experiential learning may increase the impact of rural-focused lessons in physical therapy education.
Nurse practitioner residency and fellowship programs: The controversy still exists
Authors: Meissen Heather
Published: August 2019

Postgraduate training, otherwise termed residency or fellowship training, for nurse practitioners is a growing trend. Many new graduates are seeking intensive and immersive clinical experiences supported by evidence-based didactic learning directly related to their clinical experience. This article describes current trends and evidence supporting fellowship training.
Addressing alcohol misuse in primary care
Authors: Conklin Teresa M.
Published: August 2019

Background:

Alcohol misuse (AM) among young adults remains a public health issue that is underaddressed in primary care. Despite well-supported recommendations to screen and offer brief interventions for AM, most primary care providers do not address the issue.

Local problem:

Increasing rates of alcohol-related incidents and lack of a standardized alcohol Screening and Brief Intervention (SBI) program were identified in a private university health center.

Methods:

Nurse practitioners, staff nurses, and physicians received education on alcohol SBI. Young adult students visiting a college health center were administered the Alcohol Use Disorders Identification Test-Consumption electronically followed by a brief motivational intervention if they screened positive using embedded Electronic Health Record templates. Preimplementation/postimplementation chart audit and surveys were used to evaluate effectiveness.

Interventions:

Following staff education, a standardized alcohol SBI program was implemented in a private university health center.

Results:

Increased alcohol screening and intervention rates, as well as increased knowledge about AM, and reduced alcohol use among participants were identified.

Conclusions:

Through staff education and by embedding standard alcohol SBI templates, more at-risk young adults were identified and rendered alcohol interventions during routine visits. This replicable program can improve outcomes related to AM in the primary care setting.