bluuebunny/crossref_metadata_2025 huggingface dataset:
Lung morphometry using hyperpolarized 129Xe multi‐b diffusion MRI with compressed sensing in healthy subjects and patients with COPD
Authors: Zhang Huiting , Xie Junshuai , Xiao Sa , Zhao Xiuchao , Zhang Ming , Shi Lei , Wang Ke , Wu Guangyao , Sun Xianping , Ye Chaohui , Zhou Xin
Published: May 2018

Purpose

To demonstrate the feasibility of compressed sensing (CS) to accelerate the acquisition of hyperpolarized (HP) 129Xe multi‐b diffusion MRI for quantitative assessments of lung microstructural morphometry.

Methods

Six healthy subjects and six chronic obstructive pulmonary disease (COPD) subjects underwent HP 129Xe multi‐b diffusion MRI (b = 0, 10, 20, 30, and 40 s/cm2). First, a fully sampled (FS) acquisition of HP 129Xe multi‐b diffusion MRI was conducted in one healthy subject. The acquired FS dataset was retrospectively undersampled in the phase encoding direction, and an optimal twofold undersampled pattern was then obtained by minimizing mean absolute error (MAE) between retrospective CS (rCS) and FS MR images. Next, the FS and CS acquisitions during separate breath holds were performed on five healthy subjects (including the above one). Additionally, the FS and CS synchronous acquisitions during a single breath hold were performed on the sixth healthy subject and one COPD subject. However, only CS acquisitions were conducted in the rest of the five COPD subjects. Finally, all the acquired FS, rCS and CS MR images were used to obtain morphometric parameters, including acinar duct radius (R), acinar lumen radius (r), alveolar sleeve depth (h), mean linear intercept (Lm), and surface‐to‐volume ratio (SVR). The Wilcoxon signed‐rank test and the Bland–Altman plot were employed to assess the fidelity of the CS reconstruction. Moreover, the t‐test was used to demonstrate the effectiveness of the multi‐b diffusion MRI with CS in clinical applications.

Results

The retrospective results demonstrated that there was no statistically significant difference between rCS and FS measurements using the Wilcoxon signed‐rank test (P > 0.05). Good agreement between measurements obtained with the CS and FS acquisitions during separate breath holds was demonstrated in Bland–Altman plots of slice differences. Specifically, the mean biases of the R, r, h, Lm, and SVR between the CS and FS acquisitions were 1.0%, 2.6%, −0.03%, 1.5%, and −5.5%, respectively. Good agreement between measurements with the CS and FS acquisitions was also observed during the single breath‐hold experiments. Furthermore, there were significant differences between the morphometric parameters for the healthy and COPD subjects (P < 0.05).

Conclusions

Our study has shown that HP 129Xe multi‐b diffusion MRI with CS could be beneficial in lung microstructural assessments by acquiring less data while maintaining the consistent results with the FS acquisitions.
Preliminary assessment of stable nitrogen and oxygen isotopic composition of USGS51 and USGS52 nitrous oxide reference gases and perspectives on calibration needs
Authors: Ostrom Nathaniel E. , Gandhi Hasand , Coplen Tyler B. , Toyoda Sakae , Böhlke J.K. , Brand Willi A. , Casciotti Karen L. , Dyckmans Jens , Giesemann Anette , Mohn Joachim , Well Reinhard , Yu Longfei , Yoshida Naohiro
Published: May 2018

Rationale

Despite a long history and growing interest in isotopic analyses of N2O, there is a lack of isotopically characterized N2O isotopic reference materials (standards) to enable normalization and reporting of isotope‐delta values. Here we report the isotopic characterization of two pure N2O gas reference materials, USGS51 and USGS52, which are now available for laboratory calibration (https://isotopes.usgs.gov/lab/referencematerials.html).

Methods

A total of 400 sealed borosilicate glass tubes of each N2O reference gas were prepared from a single gas filling of a high vacuum line. We demonstrated isotopic homogeneity via dual‐inlet isotope‐ratio mass spectrometry. Isotopic analyses of these reference materials were obtained from eight laboratories to evaluate interlaboratory variation and provide preliminary isotopic characterization of their δ15N, δ18O, δ15Nα, δ15Nβ and site preference (SP) values.

Results

The isotopic homogeneity of both USGS51 and USGS52 was demonstrated by one‐sigma standard deviations associated with the determinations of their δ15N, δ18O, δ15Nα, δ15Nβ and SP values of 0.12 mUr or better. The one‐sigma standard deviations of SP measurements of USGS51 and USGS52 reported by eight laboratories participating in the interlaboratory comparison were 1.27 and 1.78 mUr, respectively.

Conclusions

The agreement of isotope‐delta values obtained in the interlaboratory comparison was not sufficient to provide reliable accurate isotope measurement values for USGS51 and USGS52. We propose that provisional values for the isotopic composition of USGS51 and USGS52 determined at the Tokyo Institute of Technology can be adopted for normalizing and reporting sample data until further refinements are achieved through additional calibration efforts.
MIM2018 Conference report: Continuing positive outlook
Authors: Capus Joseph
Published: May 2018

The recent MIM2018 Conference held in Irvine, California, was the most successful yet, with record-breaking attendance. Summaries of selected presentations reported here cover developments in materials, processes and products.
In vitro nematicidal effect of Chenopodium ambrosioides and Castela tortuosa n-hexane extracts against Haemonchus contortus (Nematoda) and their anthelmintic effect in gerbils
Authors: Zamilpa A. , García-Alanís C. , López-Arellano M.E. , Hernández-Velázquez V.M. , Valladares-Cisneros M.G. , Salinas-Sánchez D.O. , Mendoza-de Gives P.
Published: May 2018

The in vitro nematicidal effect of Chenopodium ambrosioides and Castela tortuosa n-hexane extracts (E-Cham and E-Cato, respectively) on Haemonchus contortus infective larvae (L3) and the anthelmintic effect of these extracts against the pre-adult stage of the parasite in gerbils were evaluated using both individual and combined extracts. The in vitro confrontation between larvae and extracts was performed in 24-well micro-titration plates. The results were considered 24 and 72 h post confrontation. The in vivo nematicidal effect was examined using gerbils as a study model. The extracts from the two assessed plants were obtained through maceration using n-hexane as an organic agent. Gerbils artificially infected with H. contortus L3 were treated intraperitoneally with the corresponding extract either individually or in combination. The results showed that the highest individual lethal in vitro effect (96.3%) was obtained with the E-Cham extract at 72 h post confrontation at 40 mg/ml, followed by E-Cato (78.9%) at 20 mg/ml after 72 h. The highest combined effect (98.7%) was obtained after 72 h at 40 mg/ml. The in vivo assay showed that the individual administration of the E-Cato and E-Cham extracts reduced the parasitic burden in gerbils by 27.1% and 45.8%, respectively. Furthermore, the anthelmintic efficacy increased to 57.3% when both extracts were administered in combination. The results of the present study show an important combined nematicidal effect of the two plant extracts assessed against L3 in gerbils.
Food insecurity and depressive symptoms of older adults living alone in South Korea
Authors: KIM YOUNGMI , PARK AELY , KIM KYEONGMO
Published: May 2018

In South Korea, the number of older adults living alone is rapidly increasing with the growth of the ageing population. Although there is some evidence of a link between financial strain and depression in this population, there is limited empirical evidence on the relationship between food insecurity and depression in older adults living alone despite the fact that they have a high prevalence of food insecurity and tend to seek food assistance. This study aims to investigate whether food insecurity explains depressive symptoms in Korean older adults living alone. We employed data from the Korea Welfare Panel Study collected from a large-scale national sample in South Korea. Our sample consisted of 815 older adults aged 65 or older who lived alone. Conducting ordinary least square regression analyses, we tested the main effect of food insecurity on depression and the interaction effect of food insecurity and low income. We found that the relationship between food insecurity and depressive symptoms differed by low-income status (b = 6.27, p = 0.047). The association was significant only in the low-income group (b = 1.37, p = 0.04). These findings suggest that protecting access to food may be a promising strategy to lessen depressive symptoms associated with financial strain among older adults living alone.
Are soils under monodominant Gilbertiodendron dewevrei and under adjacent mixed forests similar? A case study in the Democratic Republic of Congo
Authors: Lokonda Michel , Freycon Vincent , Gourlet-Fleury Sylvie , Kombele Ferdinand
Published: May 2018

Soil has been proposed as a driver explaining the development of monodominant forests in the tropics, for example, Gilbertiodendron dewevrei forests (GDF) in central Africa. The aim of this study was to compare the physical and chemical properties of soils under GDF with those under an adjacent mixed forest (AMF), while controlling for topography. To this end, we set up sixteen 0.25-ha plots according to forest type and topography (plateau vs. bottomland), in the Yoko forest reserve, Democratic Republic of Congo. In each plot, we measured litter thickness and collected a total of 80 soil samples at depths of 0–5, 5–10, 10–20, 20–40 and 120–150 cm, for standard physical and chemical analyses. When controlling for topography and soil texture, we found that most of the chemical properties of soils under GDF did not differ from those of soils under AMF, particularly acidity, cation concentration, total N and the C:N ratio. The litter layer was 2.3 times thicker under GDF than under AMF stands, and, for a given texture, soils under GDF had a slightly higher organic C concentration in the 0–5 cm soil layer. This study suggests that G. dewevrei stands modify organic matter dynamics, which may be important in maintaining its monodominance.
NGO grassroots participatory approaches to promoting sustainable agriculture: reality or Myth in Ghana's Upper-West Region?
Authors: Beyuo Alexis
Published: May 2018

Many NGOs pride themselves with their ability to use grassroots participatory approaches when working with economically disadvantaged farmers. I asked whether current participatory approaches could be relied on to promote sustainable agriculture among subsistence farmers in Ghana's Upper-West Region. To ascertain this, I employed Arnstein's (2015) ladder of citizen participation as a theoretical basis. A two-phase exploratory sequential mixed method design was also used. Phase one consisted of a qualitative comparative analysis of the various participatory approaches of two purposively sampled NGOs using FGDs and in-depth interviews. In phase two, themes from phase one guided the formulation of a structured questionnaire, which ascertained the differences in grassroots participatory approaches between the two identified NGOs and how these differences influenced the likelihood of their respective beneficiary farmers adopting sustainable agronomic practices using chi-square and logistic regression. Findings show statistically significant associations between grassroots participation and farmers’ adoption of sustainable agronomic practices. The findings suggest that farmers who were engaged in higher levels of Arnstein's (2015) typology of participation were more likely to adopt sustainable agronomic practices than those who minimally participated. This suggests that development interventions can be most beneficial to the grassroots when intended beneficiaries fully participate in them.
Extremely Low‐Frequency Waves Inside the Diamagnetic Cavity of Comet 67P/Churyumov‐Gerasimenko
Authors: Madsen B. , Wedlund C. Simon , Eriksson A. , Goetz C. , Karlsson T. , Gunell H. , Spicher A. , Henri P. , Vallières X. , Miloch W. J.
Published: May 2018

The European Space Agency/Rosetta mission to comet 67P/Churyumov‐Gerasimenko has provided several hundred observations of the cometary diamagnetic cavity induced by the interaction between outgassed cometary particles, cometary ions, and the solar wind magnetic field. Here we present the first electric field measurements of four preperihelion and postperihelion cavity crossings on 28 May 2015 and 17 February 2016, using the dual‐probe electric field mode of the Langmuir probe (LAP) instrument of the Rosetta Plasma Consortium. We find that on large scales, variations in the electric field fluctuations capture the cavity and boundary regions observed in the already well‐studied magnetic field, suggesting the electric field mode of the LAP instrument as a reliable tool to image cavity crossings. In addition, the LAP electric field mode unravels for the first time extremely low‐frequency waves within two cavities. These low‐frequency electrostatic waves are likely triggered by lower‐hybrid waves observed in the surrounding magnetized plasma.
Electrical Resistivity of Fe‐C Alloy at High Pressure: Effects of Carbon as a Light Element on the Thermal Conductivity of the Earth's Core
Authors: Zhang Chengwei , Lin Jung‐Fu , Liu Ying , Feng Shaomin , Jin Changqing , Hou Mingqiang , Yoshino Takashi
Published: May 2018

We measured the electrical resistivity of iron, Fe99C1, Fe3C, and Fe7C3 up to ~80 GPa using the van der Pauw method in a diamond anvil cell. The electrical resistivity of disordered Fe99C1 at high pressure shows a strong impurity resistivity of carbon. The ferromagnetic‐paramagnetic transition in Fe3C and Fe7C3 is associated with the flattening of the resistivity pressure gradient at ~6 GPa. Fe7C3 exhibits the highest electrical resistivity among all iron‐light element alloys, and Fe3C and Fe7C3 disobey the Matthiessen's rule by showing a lower electrical resistivity than a disordered iron‐carbon alloy because of chemical ordering. A comparison of the impurity resistivity between silicon, sulfur, nickel, and carbon shows that carbon has an exceedingly stronger alloying effect than other elements. If the chemical ordering observed in Fe‐Si system is held true for the Fe‐C system, the chemical ordering in Fe7C3 possibly increases the thermal conductivity of the inner core and enlarges the thermal and electrical conductivity gap at the inner‐core boundary. Models of the thermal conductivity of liquid Fe70C30 with 8.4 wt % carbon show a low thermal conductivity of 38 Wm−1 K−1 at the pressure‐temperature conditions of the topmost outer core. The corresponding heat flow of 6 TW at the core‐mantle boundary is notably lower than previous electrical resistivity results on Fe and Fe alloys. The alloying effect of carbon on the electrical and thermal conductivity of iron can thus play a significant role in understanding the heat flux at the core‐mantle boundary and the thermal evolution of the core.
Lake‐Atmosphere Heat Flux Dynamics of a Thermokarst Lake in Arctic Siberia
Authors: Franz D. , Mammarella I. , Boike J. , Kirillin G. , Vesala T. , Bornemann N. , Larmanou E. , Langer M. , Sachs T.
Published: May 2018

We conducted eddy covariance measurements from April to August 2014 on a Siberian thermokarst lake. The study site is located in the Lena River Delta and characterized as a floating ice lake. Heat fluxes differed in magnitudes, directions and temporal patterns depending on the lake surface conditions (“frozen” ice cover, ice cover melt, and open water). Significant heat release during frozen ice cover conditions highlighted the importance of lakes for the landscape heat budget and water balance. The energy balance was nearly closed during the open water period and highlighted the impact of melting energy on its closure during the ice cover period. Sensible and latent heat dynamics were driven by temperature and water vapor gradients scaled by wind speed, respectively. We calculated bulk aerodynamics transfer coefficients and evaluated the performance of the derived in situ and three independent heat flux parameterization schemes. We found that bulk transfer models perform moderately to poorly for the different lake surface conditions. During the open water period small‐scale temporal variability could not be represented by the models, particularly in case of latent heat flux. The model results were less sensitive to the specific model type than to the accuracy of the surface water temperature measurement, which is dependent on a well‐thought‐out measurement design. Our study stresses considerations that are crucial for similar campaigns in the future, in order to face the measurement challenges encountered on arctic lakes especially during the ice cover period.
Sensitivity of Radiative‐Convection Equilibrium to Divergence Damping in GFDL‐FV3‐Based Cloud‐Resolving Model Simulations
Authors: Anber Usama M. , Jeevanjee Nadir , Harris Lucas M. , Held Isaac M.
Published: May 2018

Using a nonhydrostatic model based on a version of Geophysical Fluid Dynamics Laboratory's FV3 dynamical core at a cloud‐resolving resolution in radiative‐convective equilibrium (RCE) configuration, the sensitivity of the mean RCE climate to the magnitude and scale‐selectivity of the divergence damping is explored. Divergence damping is used to reduce small‐scale noise in more realistic configurations of this model. This sensitivity is tied to the strength (and width) of the convective updrafts, which decreases (increases) with increased damping and acts to organize the convection, dramatically drying out the troposphere and increasing the outgoing longwave radiation. Increased damping also results in a much‐broadened precipitation probability distribution and larger extreme values, as well as reduction in cloud fraction, which correspondingly decreases the magnitude of shortwave and longwave cloud radiative effects. Solutions exhibit a monotonic dependence on the strength of the damping and asymptotically converge to the inviscid limit. While the potential dependence of RCE simulations on resolution and microphysical assumptions are generally appreciated, these results highlight the potential significance of the choice of subgrid numerical diffusion in the dynamical core.
The Impact of Vertical Mixing Biases in Large‐Eddy Simulation on Nocturnal Low Clouds
Authors: van Stratum B. J. H. , Stevens B.
Published: May 2018

The use of large‐eddy simulation at a resolution insufficient to resolve the largest turbulent eddies frequently suffers from an overestimation of vertical mixing in the nocturnal boundary layer. The resulting biases in the mean thermodynamic structure—typically an overestimation of the near‐surface temperature, and underestimation of the boundary layer top temperature—could potentially influence the formation of low clouds or fog. Whether this is likely to happen is assessed using both observations, and a newly developed conceptual model. First, observations from Northwestern Europe (Germany and Netherlands) are used to characterize the humidity conditions at night. The results indicate that saturation most likely occurs at the surface, but that the conditions at 200 m height are also often close to saturation. Second, the conceptual model is used to study whether overestimating vertical mixing, and the resulting negative temperature biases at the boundary layer top, could result in a spurious formation of low clouds in large‐eddy simulations. The results convincingly indicate that this is unlikely to happen, as overestimating vertical mixing decreases the relative humidity throughout the nocturnal boundary layer.
Constitutive Law for Earthquake Production Based on Rate‐and‐State Friction: Dieterich 1994 Revisited
Authors: Heimisson Elias R. , Segall Paul
Published: May 2018

Dieterich (1994, https://doi.org/10.1029/93JB02581) derived a constitutive law for earthquake production based on rate‐and‐state friction, which has since been applied widely to earthquake triggering in various tectonic settings. Here this influential work is revisited and rederived in a more straightforward manner. Our derivation is based on computing the time to instability for a population of sources, and eschews the seismicity state variable. We demonstrate the validity of the Dieterich (1994) model for arbitrary shear stressing history at constant normal stress; however, our results differ slightly if fault normal stress changes with time. We provide simple integral expressions for the cumulative number of events and seismicity rate for arbitrary stressing history. These expressions have no explicit dependence on the time derivative of the stressing history. The simpler derivation makes it easier to assess and generalize various model assumptions in the original formulation. A principal success of the Dieterich (1994) theory is that it predicts and gives physical meaning to the Omori decay of seismicity rate following a stress step. We analyze the assumption that sources are well above steady state and find that Omori decay is produced by sources that either start or end up above steady state following the stress step. If no sources are brought above steady state by the perturbation then the time to reach steady state must be considered, and there will be no Omori sequence.
The Impact of Surface Heterogeneities and Land‐Atmosphere Interactions on Shallow Clouds Over ARM SGP Site
Authors: Xiao Heng , Berg Larry K. , Huang Maoyi
Published: May 2018

Continental shallow clouds are an important component of the land‐atmosphere coupled climate system because of their role in modulating energy and water budgets. The parameterization of these clouds in climate models presents a significant challenge. We evaluate the potential impact of subgrid‐scale (for climate models) land‐atmosphere interactions on shallow clouds using nested large‐eddy simulations (LESs). We compare LESs that allow for land‐atmosphere interactions to ones that artificially suppress all or part of them by smoothing out surface heterogeneities in surface heat, moisture and radiation fluxes within the domain. The LES domains are coupled to an interactive land surface model and nested inside a mesoscale domain. Three summertime shallow convection cases over the Department of Energy Atmospheric Radiation Measurement Facility's Southern Great Plains site are examined. A consistent increase in cloud water content is observed in all cases when surface heterogeneities and the land‐atmosphere interactions they induce in the LES domain are removed. By comparing experiments where only surface flux heterogeneities induced by cloud shadows are removed to ones where all surface flux heterogeneities are removed, we find that cloud shading‐induced surface heterogeneities can have a larger impact on shallow convection than static land surface heterogeneities in our cases. Furthermore, the impact of cloud shading on cloud water content and cloud size is found to vary significantly with the solar incidence angle. Our results suggest that the impact of cloud shadows needs to be considered when parameterizing land‐atmosphere interactions in the presence of shallow clouds for regional or global climate models.
Time-lapse monitoring of TLR2 ligand internalization with newly developed fluorescent probes
Authors: Arai Yohei , Yokoyama Kouhei , Kawahara Yuki , Feng Qi , Ohta Ippei , Shimoyama Atsushi , Inuki Shinsuke , Fukase Koichi , Kabayama Kazuya , Fujimoto Yukari
Published: May 2018

Bacterial lipopeptide fluorescent probes were developed as TLR2 ligands, and their time-lapse monitoring of cellular internalization was performed.
A high-resolution colorimetric immunoassay platform realized by coupling enzymatic multicolor generation with smartphone readout
Authors: Xie Wenyue , Lei Lingli , Tian Meiling , Zhang Zeying , Liu Yingshuai
Published: May 2018

A high-resolution colorimetric immunoassay platform is developed based on dual enzyme-catalyzed multicolor generation and smartphone-assisted signal readout.
Enhanced field-emission properties of buckled α-borophene by means of Li decoration: a first-principles investigation
Authors: Zheng Bing , Qiao Liang , Yu Hai-tao , Wang Qi-yue , Xie Ying , Qu Chao-qun
Published: May 2018

Li decoration and external electric field decrease the potential barrier to electron emission and increase field emission current of buckled α-borophene.
Efficient nitrogen fixation to ammonia on MXenes
Authors: Shao Mengmeng , Shao Yangfan , Chen Wenzhou , Ao Kin Long , Tong Rui , Zhu Qing , Chan Iat Neng , Ip Weng Fai , Shi Xingqiang , Pan Hui
Published: May 2018

Nitrogen can be easily adsorbed onto the surfaces of Mo2C and W2C MXenes, and then the nitrogen is effectively converted to ammonia.
Remarkable electron and phonon band structures lead to a high thermoelectric performance ZT > 1 in earth-abundant and eco-friendly SnS crystals
Authors: He Wenke , Wang Dongyang , Dong Jin-Feng , Qiu Yang , Fu Liangwei , Feng Yue , Hao Yujie , Wang Guangtao , Wang Jinfeng , Liu Chang , Li Jing-Feng , He Jiaqing , Zhao Li-Dong
Published: May 2018

Enhanced electrical transport properties and low thermal conductivity lead to high figure of merit (ZT) over the whole temperature range in Na-doped SnS crystals.
Theranostic system based on NaY(Mn)F4:Yb/Er upconversion nanoparticles with multi-drug resistance reversing ability
Authors: Chen Xiaoqin , Sun Jing , Zhao Huan , Yang Ke , Zhu Yuda , Luo Hongrong , Yu Kui , Fan Hongsong , Zhang Xingdong
Published: May 2018

An innovative theranostic system (D-UNT) for MDR tumors diagnosis and therapy based on the red emitter NaY(Mn)F4:Yb/Er with optimized luminescence was developed.
Tuning the electronic properties of germanene by molecular adsorption and under an external electric field
Authors: Liu G. , Luo W. W. , Wang X. , Lei X. L. , Xu B. , Ouyang C. Y. , Liu S. B.
Published: May 2018

Tuning the electronic properties of germanene by molecular adsorption and under an E-field.
A self-healing, adaptive and conductive polymer composite ink for 3D printing of gas sensors
Authors: Wu Tongfei , Gray Euan , Chen Biqiong
Published: May 2018

A graphene/polyborosiloxane composite exhibited self-healing, adaptive and electrically conductive properties and could be 3D printed into gas sensors.
2D superlattice nanostructures formed via self-assembly of discotic liquid crystals dominated by long range dipole–dipole interaction
Authors: Zhang Zhenhu , Yang Huanzhi , Zhang Ao , Bi Jingze , Feng Yuwen , Zhang Wanying , Zhang Chunxiu , Pu Jialing
Published: May 2018

2D organic superlattice nanostructures were formed via hierarchical self-assembly of discotic liquid crystals, which were demonstrated by X-ray diffraction pattern and TEM.
Time‐domain approach for LFM signal parameter estimation based on FPGA
Authors: Zhang Peng , Wang Ping , Cheng Julian
Published: May 2018

An FPGA‐based parameter estimation method for linear frequency modulation (LFM) signal is proposed. The average frequency value of basic time slice is obtained by using improved time‐domain counting method. Then, frequency values are used for the least‐squares fitting, so as to obtain the sweep rate of LFM signal. Compared to estimation methods based on digital signal processing, the proposed approach can effectively reduce the estimation time. Experimental results show that the slope fitting accuracy of mono‐component LFM signal is better than 99.8% and the processing time is <250 ns.
Miniaturised artificial magnetic conductor and its application in unidirectional circularly polarised slot antenna design
Authors: Li Jianxing , Huo Huimin , Chen Juan , Zhu Shitao , Shi Hongyu , Zhang Anxue
Published: May 2018

A polarisation independent artificial magnetic conductor (AMC) miniaturised using interdigital capacitors is investigated. Its performance is analysed and compared with two other previously reported AMCs. Then, a circularly polarised square slot antenna (CPSSA) utilising the proposed AMC as a reflector is implemented, which achieves unidirectional radiation and low profile simultaneously. The CPSSA is fed by a coplanar waveguide and loaded by two L‐shaped strips placed around two diagonal corners, providing the required perturbation for circular polarisation radiation. In between the slot antenna and the AMC reflector is an air gap layer. The performance comparison of the whole antenna system employing different reflectors (three AMCs and one perfect electric conductor (PEC)) proves the advantage of the proposed AMC. As for the fabricated antenna prototype, the measured 10 dB return loss impedance bandwidth and 3 dB axial ratio bandwidth are 15.9 and 4.1%, respectively, corresponding to the centre frequency of 2.71 GHz. In addition, an almost constant gain of around 5.5 dBic has been obtained across the circular polarisation bandwidth within an overall antenna volume of 0.54λ0 × 0.54λ0 × 0.08λ0.
Variety of Enriching Early-Life Activities Linked to Late-Life Cognitive Functioning in Urban Community-Dwelling African Americans
Authors: Chan Thomas , Parisi Jeanine M , Moored Kyle D , Carlson Michelle C
Published: May 2018

Objectives

The early environment is thought to be a critical period in understanding the cognitive health disparities African Americans face today. Much is known about the positive role enriching environments have in mid- and late-life and the negative function adverse experiences have in childhood; however, little is known about the relationship between enriching childhood experiences and late-life cognition. The current study examines the link between a variety of enriching early-life activities and late-life cognitive functioning in a sample of sociodemographic at-risk older adults.

Method

This study used data from African Americans from the Brain and Health Substudy of the Baltimore Experience Corps Trial (M = 67.2, SD = 5.9; N = 93). Participants completed a battery of neuropsychological assessments and a seven-item retrospective inventory of enriching activities before age 13.

Results

Findings revealed that a greater enriching early-life activity score was linked to favorable outcomes in educational attainment, processing speed, and executive functioning.

Discussion

Results provide promising evidence that enriching early environments are associated with late-life educational and cognitive outcomes. Findings support the cognitive reserve and engagement frameworks, and have implications to extend life-span prevention approaches when tackling age-related cognitive declines, diseases, and health disparities.
Reappraising the Efficacy and Acceptability of Multicomponent Interventions for Caregiver Depression in Dementia: The Utility of Network Meta-Analysis
Authors: Liew Tau Ming , Lee Cia Sin
Published: May 2018

Background

Previous meta-analyses have demonstrated the efficacy of interventions for caregiver depression in dementia. However, they generally lumped the interventions together without accounting for the multicomponent nature of most interventions. It is unknown which combination of components contributed to the efficacy and should be implemented in clinical practice.

Objectives

To reappraise the interventions for caregiver depression from a recent systematic review, and evaluate whether a network meta-analytic approach offers additional insight into the efficacy and acceptability of multicomponent interventions.

Research Design and Methods

This study built upon a recent systematic review which identified 33 RCTs on caregiver depression from multiple databases (Medline, EMBASE, CENTRAL, PsycINFO, PSYNDEX). The 33 RCTs had different combinations of components serving at least one of the three key functions: addressing the care needs of persons with dementia (“CN”), addressing caregiving competency (“CC”), and providing emotional support for loss and grief (“ES”). A Bayesian network meta-analysis was conducted to compare the efficacy and all-cause attrition across different combinations of interventions.

Results

CN–CC combination was significantly more efficacious than treatment-as-usual (standardized mean difference in depression scores, SMD = −0.25, 95% credible interval [CrI] = −0.41 to −0.08) and marginally better than CN (SMD = −0.43, 95% CrI = −0.85 to −0.00). While none of the interventions clearly had both high efficacy and acceptability, three combinations of interventions (CC, CN–CC, and CN–CC–ES) had a reasonable balance between efficacy and acceptability.

Discussion and Implications

Although interventions for caregiver depression in dementia are effective in general, the different components of interventions may not share the same efficacy and acceptability. In implementing interventions, policymakers may consider addressing CC first, introducing CN in a graded manner, and providing ES only when indicated. Future studies may also consider using network meta-analysis to gain additional insights on how to implement multicomponent interventions in geriatric care.
Sustainable development goals for health promotion: a critical frame analysis
Authors: Spencer Grace , Corbin J Hope , Miedema Esther
Published: May 2018

The Sustainable Development Goals (SDGs) lay the foundations for supporting global health and international development work for the next 15 years. Thirty years ago, the Ottawa Charter defined health promotion and outlined key principles for global action on health, including the importance of advocating, enabling and mediating for health equity. Advocacy underscores a human right to health and suggests political action to support its attainment. Enabling speaks to health promotion’s focus on the empowerment of people and communities to take control over their health and aspirations. Mediation draws attention to the critical intersectoral partnerships required to address health and social inequities. Underpinned by this approach, the aim of this paper is to consider how key health promotion principles, namely, rights, empowerment and partnership feature (and are framed) within the SDGs and to consider how these framings may shape future directions for health promotion. To that end, a critical frame analysis of the Transforming Our World document was conducted. The analysis interrogated varying uses and meanings of partnerships, empowerment and rights (and their connections) within the SDGs. The analysis here presents three framings from the SDGs: (1) a moral code for global action on (in)equity; (2) a future orientation to address global issues yet devoid of history; and (3) a reductionist framing of health as the absence of disease. These framings raise important questions about the underpinning values of the SDGs and pathways to health equity – offering both challenges and opportunities for defining the nature and scope of health promotion.
From Mini to Maxi Jobs? Low Pay, ‘Progression’, and the Duty to Work (Harder)
Authors: Puttick Keith
Published: May 2018

The scale of low pay and in-work poverty affecting the bottom three deciles of the labour market highlights the weaknesses in the two main mechanisms for assisting the low-paid: the statutory minimum wage provided for by the National Minimum Wage Act 1998 and State in-work benefits, particularly Universal Credit (UC) as it operates under the Welfare Reform Act 2012 and Universal Credit Regulations 2013. Both mechanisms are failing badly. The paper argues for new approaches. On the Labour side of what may be called the Labour Law–Social Security Law interface these include reconstruction of the national minimum wage scheme in the 1998 Act so that there are two minimum wage floors: a primary floor based on the current national scheme; and a higher, secondary floor at sectoral level. Sectoral wage-setting, informed by support from a Low Pay Commission with an extended remit, could in time pave the way to wider-ranging, regulated sectoral collective bargaining and systems which align more closely and efficiently to what employers can afford, and relieve the growing fiscal pressures on in-work social security. On the Social Security side, remedial work on UC is urgently needed, particularly on the work allowances which set the earnings thresholds at which in-work State support starts to be withdrawn. If mandatory ‘progression’ requirements under the in-work progression (IWP) scheme are to continue—which is likely given the government’s concern that, without this, workers in low hours, low paid mini jobs will opt to stay parked in such highly subsidised work—then exemptions and protections need to be strengthened and put on a statutory footing (particularly for workers with family responsibilities). Introducing what would, in effect, be a ‘right not to work’ in prescribed cases—typically when requirements impact disproportionately on workers and their family members—would go some way to establishing the necessary safeguards. Clearly, both low pay mechanisms face a crisis of growing proportions: a crisis of coverage as dependence grows and newer groups look to the State for support; a fiscal crisis as costs rise and cuts to support impact on its effectiveness; and a political crisis as support for UC and the wider low pay regime erodes.
Rethinking the shortage of primary care physicians
Authors: Hackey Robert B. , Grasso Victoria , LaRochelle Madeleine , Seaver Katelyn
Published: May 2018

For decades, public concerns about a shortage of physicians led federal and state policy makers to pursue policies to increase the number of medical graduates. In response, the number of medical schools increased dramatically over the past decade. By 2016, the United States produced more new physicians than ever before. Expanding medical school enrollments, however, were not matched by a corresponding increase in the number of physicians choosing primary care. To date, few policy makers questioned the conventional wisdom that more is better when it comes to the supply of primary care physicians. Instead, policy makers should consider alternative approaches to increase access to patient-centered primary care.
Gun Violence: Two Medical Students’ Hometown Connection to This Public Health Crisis
Authors: Kuhl Nicholas O. , Lieberman Monica P.
Published: May 2018

The school shooting in Parkland, Florida in February 2018 left 17 people dead and countless other children and teachers with physical and psychological trauma that will require decades of healing. As Marjory Stoneman Douglas High School alumni and current medical students, the authors of this Invited Commentary contend that they are in a unique position to advocate on behalf of their neighbors, classmates, and future patients. Since the authors began medical school in 2015, there have been 19 mass shootings in the United States, resulting in 253 deaths. During this same time period, there have been nearly 100,000 gun-related deaths in the United States. While 60.7% of those gun deaths were suicides, the public must not, and should not, attribute all gun violence to the spectrum of psychiatric diagnoses. Several studies have shown that increased access to firearms directly increases the rate of one of the United States’ most pressing public health issues—gun violence. Despite this fact, and as the result of misguided health policies like the Dickey Amendment, the funding for research on gun violence pales in comparison with that for other leading causes of death. Consequently, the health care community has long been without adequate data to engage in evidence-based gun violence prevention and education efforts. As two students on the cusp of beginning their medical careers, the authors argue that they and other health care providers can no longer sit idly on the sidelines as this public health crisis continues to impact the United States.
The International Partner as Invited Guest: Beyond Colonial and Import–Export Models of Medical Education
Authors: Whitehead Cynthia , Wondimagegn Dawit , Baheretibeb Yonas , Hodges Brian
Published: May 2018

The dominant model of international collaboration in medical education, both currently and in the past two centuries, is one of foreign (i.e., Euro-American) ownership and control. In this Invited Commentary, the authors provide a brief selected history of such international partnerships. They then focus on recent partnership models that have alternative structures. One of these is the collaborative partnership between Addis Ababa University (AAU) and the University of Toronto. This partnership is known as the Toronto Addis Ababa Academic Collaboration (TAAAC). From the inception of this partnership, the TAAAC has aimed to be relational and has firmly placed ownership of the codeveloped curriculum at AAU. Other explicit aims of the TAAAC are to help AAU develop culturally appropriate programming that is sustainable with local resources and to develop capacity-building, coteaching models. In seeking potential precedents to the TAAAC, the authors have explored archives in Ethiopia, Canada, and the United Kingdom. They found that invited foreign guests have played a role in the development of educational systems in Ethiopia since the 1940s. The authors believe that by paying close attention to the language used to describe the nature of a relationship, medical educators may be able to move toward more collaborative, capacity-building international partnerships.
Improved Diagnosis and Treatment of Bone and Joint Infections Using an Evidence-based Treatment Guideline
Authors: Quick Rachel D. , Williams John , Fernandez Marisol , Gottschalk Hilton , Cosgrove Peter , Kahlden Kyle , Merkel Kathryn , Thoreson Lynn , Boswell Patrick , Hauger Sarmistha B.
Published: May 2018

Background:

Our institution created a multidisciplinary guideline for treatment of acute hematogenous osteomyelitis (AHO) and septic arthritis (SA) in response to updates in evidence-based literature in the field and existing provider variability in treatment. This guideline aims to improve the care of these patients by standardizing diagnosis and treatment and incorporating up to date evidence-based research into practice. The primary objective of this study is to compare cases before versus after the implementation of the guideline to determine concrete effects the guideline has had in the care of patients with AHO and SA.

Methods:

This is an Institutional Review Board-approved retrospective study of pediatric patients age 6 months to 18 years hospitalized between January 2009 and July 2016 with a diagnosis of AHO or SA qualifying for the guideline. Cohorts were categorized: preguideline and postguideline. Exclusion criteria consisted of: symptoms >14 days, multifocal involvement, hemodynamic instability, sepsis, or history of immune deficiency or chronic systemic disease. Cohorts were compared for outcomes that described clinical course.

Results:

Data were included for 117 cases that qualified for the guideline: 54 preguideline and 63 postguideline. Following the successful implementation of the guideline, we found significant decrease in the length of intravenous antibiotic treatment (P<0.001), decrease in peripherally inserted central catheter use (P<0.001), and an increase in bacterial identification (P=0.040). Bacterial identification allowed for targeted antibiotic therapy. There was no change in length of hospital stay or readmission rate after the implementation of the guideline.

Conclusion:

Utilizing an evidence-based treatment guideline for pediatric acute hematogenous bone and joint infections can lead to improved bacterial diagnosis and decreased burden of treatment through early oral antibiotic use.

Level of Evidence:

Level III– retrospective comparative study.
3D Knee Trochlear Morphology Assessment by Magnetic Resonance Imaging in Patients With Normal and Dysplastic Trochleae
Authors: Pennock Andrew T. , Chang Aileen , Doan Joshua , Bomar James D. , Edmonds Eric W.
Published: May 2018

Background:

Trochlear dysplasia is recognized as a significant risk factor for patellar instability, but current imaging modalities fail to allow full visualization and classification of the complex 3-dimensional (3D) anatomy of the trochlea. The purpose of this study was to elucidate primary differences in trochlear morphology between patients with and without patellar instability by utilizing 3D magnetic resonance imaging (MRI) reconstructions of the trochlea.

Methods:

An institutional review board-approved retrospective review included 24 patients with a diagnosis of patellar instability and an age-matched and sex-matched control population of 12 patients. 3D models of the femoral trochlea were created from MRI images and measurements were performed. 3D measurements were trochlear groove volume and surface area that were normalized to the femoral width. 2D measurements were performed throughout the length of the trochlea including the bony and cartilaginous sulcus angles as well as the bony and cartilaginous trochlear depths. Differences were also assessed between sex, skeletal maturity, and trochlear dysplasia severity.

Results:

Surface topography of the trochlea varied significantly based on location with the trochlea becoming progressively more flat proximally away from the notch (P<0.05). Patients with patella instability had reduced trochlear volumes and trochlear depths compared with control patients (P<0.05). These differences were more pronounced with the cartilaginous measurements as well as more proximally within the trochlea. Patients with high-grade dysplasia had greater reductions in trochlear volumes and depth especially proximally in the trochlea (P<0.05). Once femoral size was standardized, minimal differences were observed based on sex or skeletal maturity (P>0.05).

Conclusions:

Novel 3D MRI reconstructions demonstrated that measurements of trochlear morphology varied significantly between patients with and without patellar instability. When trochlear dysplasia is present, it appears to affect the majority of the trochlear surface, but preferentially the proximal extent. Future trochlear dysplasia classification systems may benefit from assessment of articular cartilage surface measures rather than primarily osseous structure measurements.

Level of Evidence:

Level III—case-control prognostic study.
Firearm-associated Fractures in Children and Adolescents: Trends in the United States 2003-2012
Authors: Blumberg Todd J. , DeFrancesco Christopher J. , Miller Daniel J. , Pandya Nirav K. , Flynn John M. , Baldwin Keith D.
Published: May 2018

Background:

Firearm-associated injuries are the second leading cause of death in children in the United States. Fractures are common comorbid injuries in young patients with firearm-associated injuries. The purpose of this study was to define the burden of firearm-associated fractures (FAFs) in children and adolescents in the United States.

Methods:

We analyzed the 2003-2012 Kids’ Inpatient Database. Patients were grouped into 4 age groups: 0 to 4, 5 to 9, 10 to 14, and 15 to 20 years old. Sample observations with both an external cause of injury code indicating gunshot injury and a diagnosis code indicating orthopaedic fracture (extremity, pelvis, or spine) were identified as cases of FAF. Sex, age, race, cause of injury, and fracture-related operating room procedures were catalogued. Population-level incidence was calculated for each year studied.

Results:

From 2003 to 2012, the incidence of FAF in patients 20 years and below of age increased from 73 to 96 cases per 100,000 admissions (P=0.009). The 0 to 4 age group saw the largest increase in injury frequency (141%, P=0.08). There was a 4-fold increase in the rate of unintentional injury in this subgroup. The most common age group affected by FAFs was 15 to 20 year olds. Minorities and male individuals were disproportionately affected. Assault and unintentional causes were the most common reasons for injury.

Conclusions:

The frequency of FAF in patients 20 years and below of age increased over the study period, with almost 1 case per 1000 admissions in 2012. The finding that certain subpopulations are disproportionately affected reflects the complex sociologic factors influencing gun violence in the United States.

Level of Evidence:

Level III—retrospective cohort study.