bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of a pressurized regional sea or global ocean on stresses on Enceladus
Authors: Johnston Stephanie A. , Montési Laurent G. J.
Published: May 2017

Liquid water is likely present in the interior of Enceladus, but it is still debated whether this water forms a global ocean or a regional sea and whether the present‐day situation is stable. As the heat flux of Enceladus exceeds most heat source estimates, the liquid water is likely cooling and crystallizing, which results in expansion and pressurization of the sea or ocean. We determine, using an axisymmetric Finite Element Model, the tectonic patterns that pressurization of a regional sea or global ocean might produce at the surface of Enceladus. Tension is always predicted above where the ice is thinnest and generates cracks that might be at the origin of the Tiger Stripes. Tectonic activity is also expected in an annulus around the sea if the ice shell is in contact with but slips freely along the rocky core of the satellite. Cracks at the north pole are expected if the shell slips along the core or if there is a global ocean with thin ice at the pole. Water is likely injected along the base of the ice when the shell is grounded, which may lead to cycles of tectonic activity with the shell alternating between floating and grounded states and midlatitude faulting occurring at the transition from a grounded to a floating state.
Approach for estimating the dynamic physical thresholds of phytoplankton production and biomass in the tropical‐subtropical Pacific Ocean
Authors: Gómez‐Ocampo E. , Gaxiola‐Castro G. , Durazo Reginaldo
Published: May 2017

Threshold is defined as the point where small changes in an environmental driver produce large responses in the ecosystem. Generalized additive models (GAMs) were used to estimate the thresholds and contribution of key dynamic physical variables in terms of phytoplankton production and variations in biomass in the tropical‐subtropical Pacific Ocean off Mexico. The statistical approach used here showed that thresholds were shallower for primary production than for phytoplankton biomass (pycnocline < 68 m and mixed layer < 30 m versus pycnocline < 45 m and mixed layer < 80 m) but were similar for absolute dynamic topography and Ekman pumping (ADT < 59 cm and EkP > 0 cm d−1 versus ADT < 60 cm and EkP > 4 cm d−1). The relatively high productivity on seasonal (spring) and interannual (La Niña 2008) scales was linked to low ADT (45–60 cm) and shallow pycnocline depth (9–68 m) and mixed layer (8–40 m). Statistical estimations from satellite data indicated that the contributions of ocean circulation to phytoplankton variability were 18% (for phytoplankton biomass) and 46% (for phytoplankton production). Although the statistical contribution of models constructed with in situ integrated chlorophyll a and primary production data was lower than the one obtained with satellite data (11%), the fits were better for the former, based on the residual distribution. The results reported here suggest that estimated thresholds may reliably explain the spatial‐temporal variations of phytoplankton in the tropical‐subtropical Pacific Ocean off the coast of Mexico.
New capillary number definition for displacement of residual nonwetting phase in natural fractures
Authors: AlQuaimi B. I. , Rossen W. R.
Published: May 2017

We propose a new capillary number for flow in fractures starting with a force balance on a trapped ganglion in a fracture. The new definition is validated with laboratory experiments using five distinctive model fractures. Capillary desaturation curves were generated experimentally using water‐air forced imbibition. The residual saturation‐capillary number relationship obtained from different fractures, which vary in aperture and roughness, can be represented approximately by a single curve in terms of the new definition of the capillary number. They do not fit a single trend using the conventional definition of the capillary number.
New insights into saline water evaporation from porous media: Complex interaction between evaporation rates, precipitation, and surface temperature
Authors: Shokri‐Kuehni Salomé M. S. , Vetter Thomas , Webb Colin , Shokri Nima
Published: May 2017

Understanding salt transport and deposition patterns during evaporation from porous media is important in many engineering and hydrological processes such as soil salinization, ecosystem functioning, and land‐atmosphere interaction. As evaporation proceeds, salt concentration increases until it exceeds solubility limits, locally, and crystals precipitate. The interplay between transport processes, crystallization, and evaporation influences where crystallization occurs. During early stages, the precipitated salt creates an evolving porous structure affecting the evaporation kinetics. We conducted a comprehensive series of experiments to investigate how the salt concentration and precipitation influence evaporation dynamics. Our results illustrate the contribution of the evolving salt crust to the evaporative mass losses. High‐resolution thermal imaging enabled us to investigate the complex temperature dynamics at the surface of precipitated salt, providing further confirmation of salt crust contribution to the evaporation. We identify different phases of saline water evaporation from porous media with the corresponding dominant mechanisms in each phase and extend the physical understanding of such processes.
Decoding ice sheet behavior using englacial layer slopes
Authors: Holschuh Nicholas , Parizek Byron R. , Alley Richard B. , Anandakrishnan Sridhar
Published: May 2017

The complex flow fields of the Antarctic and Greenland ice sheets deform layers deposited as snow at the ice sheet surface, leaving a record of the regional flow history and/or local transitions in basal boundary conditions within the geometry of ice sheet layers. Ice‐penetrating radar reveals these layers, but radar data interpretations are limited by the challenges of quantitatively and reproducibly comparing observations with model output. We present a conceptual framework that relates along‐track reflector slope to gradients in the steady state velocity field of ice sheets. This method makes effective use of englacial reflectors in regions where it is challenging to image continuous layers and avoids the error propagation inherent to tracer‐transport methods, developing the potential for formal radar data assimilation in future modeling studies. We apply our method to radar data collected at the grounding line of Whillans Ice Stream, where enhanced bed friction produces characteristic reflector slopes reproducible using a higher‐order ice flow model.
Depth dependence of the frictional behavior of montmorillonite fault gouge: Implications for seismicity along a décollement zone
Authors: Mizutani Tomoyo , Hirauchi Ken‐ichi , Lin Weiren , Sawai Michiyo
Published: May 2017

To understand the seismogenic potential of shallow plate‐boundary thrust faults (décollements) in relatively warm subduction zones, water‐saturated Na‐montmorillonite gouges were sheared at a pore fluid pressure of 10 MPa, effective normal stresses (σneff) of 10–70 MPa, temperatures (T) of 25–150°C, and axial displacement rates of 0.03–3 μm/s. The Na‐montmorillonite gouges were frictionally very weak at all conditions tested (steady state friction coefficient μss = 0.05–0.09). At T ≤ 60°C, Na‐montmorillonite showed a transition from velocity‐strengthening to velocity‐weakening behavior with increasing σneff, whereas at T ≥ 90°C it was largely velocity neutral or velocity strengthening, irrespective of σneff. The rates of frictional healing (β) showed extremely low values (mostly <0.001) at all temperatures. Our results suggest that the existence of Na‐montmorillonite in the décollement zone at Costa Rica and Nankai promotes aseismic slip, particularly at shallow depths, forming weakly coupled regions.
Intense deformation field at oceanic front inferred from directional sea surface roughness observations
Authors: Rascle Nicolas , Molemaker Jeroen , Marié Louis , Nouguier Frédéric , Chapron Bertrand , Lund Björn , Mouche Alexis
Published: May 2017

Fine‐scale current gradients at the ocean surface can be observed by sea surface roughness. More specifically, directional surface roughness anomalies are related to the different horizontal current gradient components. This paper reports results from a dedicated experiment during the Lagrangian Submesoscale Experiment (LASER) drifter deployment. A very sharp front, 50 m wide, is detected simultaneously in drifter trajectories, sea surface temperature, and sea surface roughness. A new observational method is applied, using Sun glitter reflections during multiple airplane passes to reconstruct the multiangle roughness anomaly. This multiangle anomaly is consistent with wave‐current interactions over a front, including both cross‐front convergence and along‐front shear with cyclonic vorticity. Qualitatively, results agree with drifters and X‐band radar observations. Quantitatively, the sharpness of roughness anomaly suggests intense current gradients, 0.3 m s−1 over the 50 m wide front. This work opens new perspectives for monitoring intense oceanic fronts using drones or satellite constellations.
Seasonally transported aerosol layers over southeast Atlantic are closer to underlying clouds than previously reported
Authors: Rajapakshe Chamara , Zhang Zhibo , Yorks John E. , Yu Hongbin , Tan Qian , Meyer Kerry , Platnick Steven , Winker David M.
Published: May 2017

From June to October, low‐level clouds in the southeast (SE) Atlantic often underlie seasonal aerosol layers transported from African continent. Previously, the Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) 532 nm lidar observations have been used to estimate the relative vertical location of the above‐cloud aerosols (ACA) to the underlying clouds. Here we show new observations from NASA's Cloud‐Aerosol Transport System (CATS) lidar. Two seasons of CATS 1064 nm observations reveal that the bottom of the ACA layer is much lower than previously estimated based on CALIPSO 532 nm observations. For about 60% of CATS nighttime ACA scenes, the aerosol layer base is within 360 m distance to the top of the underlying cloud. Our results are important for future studies of the microphysical indirect and semidirect effects of ACA in the SE Atlantic region.
On the asymmetry of the urban daily air temperature cycle
Authors: Wang Kai , Li Yuguo , Wang Yi , Yang Xinyan
Published: May 2017

The asymmetry phenomenon in daily temperature cycle refers to the smaller and decreasing diurnal temperature range, which resulted from much faster rise of the daily minimum temperature than that of the maximum temperature. The asymmetry is known to have occurred in greater magnitude in cities than rural sites. Spatially, the diurnal temperature range is much smaller in urban areas than in the surrounding rural areas. Temporally, the urban diurnal temperature range decreases much faster than that in the rural areas. Here, we demonstrate a new approach in understanding the spatial and temporal asymmetries in the urban daily air temperature cycle. Both asymmetries can be explained by a simple combination of a reduction in amplitudes with a rise in mean temperature, which are governed by difference factors. Our study provides new insights that increase our understanding of the mechanisms of urban warming.
Lags in hydrologic recovery following an extreme drought: Assessing the roles of climate and catchment characteristics
Authors: Yang Yuting , McVicar Tim R. , Donohue Randall J. , Zhang Yongqiang , Roderick Michael L. , Chiew Francis H.S. , Zhang Lu , Zhang Junlong
Published: May 2017

Drought, generally characterized by below‐average water supply, propagates through the hydrologic system with consequent ecological and societal impacts. Compared with other drought aspects, the recovery of drought especially in the hydrological components, which directly relates to the recovery of water resources for agricultural, ecological and human needs, is less‐understood. Here, taking the Millennium drought in southeast Australia (∼1997–2009) as an illustrating case, we comprehensively examined multiple aspects of the meteorological (i.e., precipitation) and hydrological (i.e., streamflow and base flow) droughts across 130 unimpaired catchments using long‐term hydro‐meteorological observations. Results show that the duration and intensity of the meteorological drought are both lengthened and amplified in the hydrological drought, suggesting a nonstationarity in the rainfall‐runoff relationship during a prolonged drought. Additionally, we find a time lag commonly exists between the end of the meteorological droughts and the end of the hydrological drought, with the recovery of base flow showing a longer lag than the recovery of streamflow. The recovery rate of precipitation after drought was found to be the dominant factor that controls the recovery of hydrological droughts while catchment landscape (i.e., valley bottom flatness) plays an important but secondary role in controlling the lags in the hydrological recovery. Other hydro‐climatic factors and catchment properties appear to have only minor influences governing hydrological drought recovery. Our findings highlight a delayed response in the terrestrial components of the hydrological cycle to precipitation after prolonged drought, and provide valuable scientific guidance to water resources management and water security assessment in regions facing future droughts.
Delays to Care in Pediatric Lupus Patients: Data From the Childhood Arthritis and Rheumatology Research Alliance Legacy Registry
Authors: Rubinstein Tamar B. , Mowrey Wenzhu B. , Ilowite Norman T. , Wahezi Dawn M. ,   the Childhood Arthritis and Rheumatology Research Alliance INVESTIGATORS
Published: May 2017

Objective

Prompt treatment for lupus is important to prevent morbidity. A potential barrier to early treatment of pediatric lupus is delayed presentation to a pediatric rheumatologist. To better understand factors contributing to delayed presentation among pediatric lupus patients, we examined differences in demographic and clinical characteristics of lupus patients within the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Legacy Registry with regard to time between symptom onset and presentation to a pediatric rheumatologist.

Methods

We analyzed data from 598 CARRA Legacy Registry participants for differences between those who presented early (within <1 month of symptom onset), between 1–3 months (typical presentation), with moderate delays (3–12 months), and with severe delays (≥1 year). Factors associated with early presentation, moderate delay, and severe delay were determined by multinomial logistic regression.

Results

Forty‐four percent of patients presented early, while 23% had moderate delays and 9% had severe delays. Family history of lupus, absence of discoid rash, and location in a state with a higher density of pediatric rheumatologists were associated with earlier presentation. Younger age, low household income (<$25,000 per year), and a family history of lupus were associated with severe delay.

Conclusion

Delays to care ≥1 year exist in a notable minority of pediatric lupus patients from the CARRA Legacy Registry. In this large and diverse sample of patients, access to care and family resources played an important role in predicting time to presentation to a pediatric rheumatologist.
Association Between Metabolic Syndrome and Radiographic Hand Osteoarthritis: Data From a Community‐Based Longitudinal Cohort Study
Authors: Strand Mette P. , Neogi Tuhina , Niu Jingbo , Felson David T. , Haugen Ida K.
Published: May 2017

Objective

To explore whether metabolic syndrome and its components are associated with hand osteoarthritis (OA) using longitudinal data from the Framingham Study.

Methods

Our cross‐sectional analyses included 1,089 persons (ages 50–75 years), of whom 785 had longitudinal radiographs obtained 7 years apart. Of these, 586 with no hand OA at baseline were included in analyses of hand OA incidence. We explored associations between metabolic syndrome and its components (central obesity, hypertension, diabetes mellitus, triglyceridemia, and low high‐density lipoprotein) and radiographic hand OA (defined as ≥2 interphalangeal joints with a Kellgren/Lawrence [K/L] grade of ≥2) using logistic regression analyses with adjustment for age, sex, and body mass index. In longitudinal analyses, metabolic syndrome was used as a predictor for change in K/L sum score and incident hand OA.

Results

Metabolic syndrome was not associated with the presence of hand OA (odds ratio [OR] 1.11 [95% confidence interval (95% CI) 0.78–1.59]), change in K/L sum score (OR 0.83 [95% CI 0.59–1.17]), or incidence of hand OA (OR 0.91 [95% CI 0.58–1.44]). Hypertension was borderline significantly associated with the presence of hand OA (OR 1.25 [95% CI 0.90–1.74]), and a significant association was found between hypertension and change in K/L sum score (OR 1.47 [95% CI 1.08–1.99]). Consistent dose‐response relationships were not demonstrated (data not shown). Furthermore, hypertension was not significantly associated with hand OA incidence (OR 1.23 [95% CI 0.82–1.83]). No significant associations were found between metabolic syndrome and erosive hand OA.

Conclusion

We found no association between metabolic syndrome and hand OA. The role of hypertension in hand OA pathogenesis warrants further investigation.
Performance of Antinuclear Antibodies for Classifying Systemic Lupus Erythematosus: A Systematic Literature Review and Meta‐Regression of Diagnostic Data
Authors: Leuchten Nicolai , Hoyer Annika , Brinks Ralph , Schoels Monika , Schneider Matthias , Smolen Josef , Johnson Sindhu R. , Daikh David , Dörner Thomas , Aringer Martin , Bertsias George ,   the Systemic Lupus Erythematosus Classification Criteria Steering Committee
Published: May 2017

Objective

To review the published literature on the performance of indirect immunofluorescence (IIF)–HEp‐2 antinuclear antibody (ANA) testing for classification of systemic lupus erythematosus (SLE).

Methods

A systematic literature search was conducted in the Medline, Embase, and Cochrane databases for articles published between January 1990 and October 2015. The research question was structured according to Population, Intervention, Comparator, Outcome (PICO) format rules, and Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) recommendations were followed where appropriate. Meta‐regression analysis for diagnostic tests was performed, using the ANA titer as independent variable, while sensitivity and specificity were dependent variables.

Results

Of 4,483 publications screened, 62 matched the eligibility criteria, and another 2 articles were identified through reference analysis. The included studies comprised 13,080 SLE patients in total, of whom 12,542 (95.9%) were reported to be IIF‐ANA positive at various titers. For ANA at titers of 1:40, 1:80, 1:160, and 1:320, meta‐regression gave sensitivity values of 98.4% (95% confidence interval [95% CI] 97.6–99.0%), 97.8% (95% CI 96.8–98.5%), 95.8% (95% CI 94.1–97.1%), and 86.0% (95% CI 77.0–91.9%), respectively. The corresponding specificities were 66.9% (95% CI 57.8–74.9%), 74.7% (95% CI 66.7–81.3%), 86.2% (95% CI 80.4–90.5%), and 96.6% (95% CI 93.9–98.1%), respectively.

Conclusion

The results of this systematic literature review and meta‐regression confirm that IIF‐ANAs have high sensitivity for SLE. ANAs at a titer of 1:80 have sufficiently high sensitivity to be considered as an entry criterion for SLE classification criteria, i.e., formally test other classification criteria for SLE only if ANAs of at least 1:80 have been found.
Cost‐Effectiveness of Tight Control of Inflammation in Early Psoriatic Arthritis: Economic Analysis of a Multicenter Randomized Controlled Trial
Authors: O'Dwyer John L. , Meads David M. , Hulme Claire T. , Mcparland Lucy , Brown Sarah , Coates Laura C. , Moverley Anna R. , Emery Paul , Conaghan Philip G. , Helliwell Philip S.
Published: May 2017

Objective

Treat‐to‐target approaches have proved to be effective in rheumatoid arthritis, but have not been studied in psoriatic arthritis (PsA). This study was undertaken to examine the cost‐effectiveness of tight control (TC) of inflammation in early PsA compared to standard care.

Methods

Cost‐effectiveness analyses were undertaken alongside a UK‐based, open‐label, multicenter, randomized controlled trial. Taking the perspective of the health care sector, effectiveness was measured using the 3‐level EuroQol 5‐domain, which allows for the calculation of quality‐adjusted life‐years (QALYs). Incremental cost‐effectiveness ratios (ICERs) are presented, which represent the additional cost per QALY gained over a 48‐week time horizon. Sensitivity analyses are presented assessing the impact of variations in the analytical approach and assumptions on the cost‐effectiveness estimates.

Results

The mean cost and QALYs were higher in the TC group: £4,198 versus £2,000 and 0.602 versus 0.561. These values yielded an ICER of £53,948 per QALY. Bootstrapped uncertainty analysis suggests that the TC has a 0.07 probability of being cost‐effective at a £20,000 threshold. Stratified analysis suggests that with certain costs being controlled, an ICER of £24,639 can be calculated for patients with a higher degree of disease severity.

Conclusion

A tight control strategy to treat PsA is an effective intervention in the treatment pathway; however, this study does not find tight control to be cost‐effective in most analyses. Lower drug prices, targeting polyarthritis patients, or reducing the frequency of rheumatology visits may improve value for money metrics in future studies.
Speech and noise power estimation using Gamma modeling
Authors: Chehrehsa Sarang , Moir Tom James
Published: May 2017

In speech enhancement, having an accurate estimation of the power of the speech and noise signals forming the noisy observation is critical, as it can highly affect the performance of the enhancement algorithm. A method is introduced in which the distributions of the power of the speech and noise periodograms are modeled using the Gamma distribution to extract their shape parameters. These shape parameters are later used in the observed noisy speech to estimate the power when forming speech and noise periodograms. This method results in more accurate and faster power estimation with respect to the well‐known minimum statistics power estimation algorithm and together with the maximum a posteriori speech enhancement algorithm exhibits good speech enhancement performance.
Bottom‐Up Preparation of Uniform Ultrathin Rhenium Disulfide Nanosheets for Image‐Guided Photothermal Radiotherapy
Authors: Shen Sida , Chao Yu , Dong Ziliang , Wang Guanglin , Yi Xuan , Song Guosheng , Yang Kai , Liu Zhuang , Cheng Liang
Published: May 2017

Facile preparation of multifunctional theranostic nanoplatforms with well‐controlled morphology and sizes remains an attractive in the area of nanomedicine. Here, a new kind of 2D transition metal dichalcogenide, rhenium disulfide (ReS2) nanosheets, with uniform sizes, strong near‐infrared (NIR) light, and strong X‐ray attenuation, is successfully synthesized. After surface modification with poly(ethylene glycol) (PEG), the synthesized ReS2‐PEG nanosheets are stable in various physiological solutions. In addition to their contrasts in photoacoustic imaging and X‐ray computed tomography imaging because of their strong NIR light and X‐ray absorptions, respectively, such ReS2‐PEG nanosheets can also be tracked under nuclear imaging after chelator‐free labeling with radioisotope ions, 99mTc4+. Efficient tumor accumulation of ReS2‐PEG nanosheets is then observed after intravenous injection into tumor‐bearing mice under triple‐modal imaging. The combined in vivo photothermal radiotherapy is further conducted, achieving a remarkable synergistic tumor destruction effect. Finally, no obvious toxicity of ReS2‐PEG nanosheets is observed from the treated mice within 30 d. This work suggests that such ultrathin ReS2 nanosheets with well‐controlled morphology and uniform sizes may be a promising type of multifunctional theranostic agent for remotely triggered cancer combination therapy.
Dual Cross‐Linked Biofunctional and Self‐Healing Networks to Generate User‐Defined Modular Gradient Hydrogel Constructs
Authors: Wei Zhao , Lewis Daniel M. , Xu Yu , Gerecht Sharon
Published: May 2017

Gradient hydrogels have been developed to mimic the spatiotemporal differences of multiple gradient cues in tissues. Current approaches used to generate such hydrogels are restricted to a single gradient shape and distribution. Here, a hydrogel is designed that includes two chemical cross‐linking networks, biofunctional, and self‐healing networks, enabling the customizable formation of modular gradient hydrogel construct with various gradient distributions and flexible shapes. The biofunctional networks are formed via Michael addition between the acrylates of oxidized acrylated hyaluronic acid (OAHA) and the dithiol of matrix metalloproteinase (MMP)‐sensitive cross‐linker and RGD peptides. The self‐healing networks are formed via dynamic Schiff base reaction between N‐carboxyethyl chitosan (CEC) and OAHA, which drives the modular gradient units to self‐heal into an integral modular gradient hydrogel. The CEC‐OAHA‐MMP hydrogel exhibits excellent flowability at 37 °C under shear stress, enabling its injection to generate gradient distributions and shapes. Furthermore, encapsulated sarcoma cells respond to the gradient cues of RGD peptides and MMP‐sensitive cross‐linkers in the hydrogel. With these superior properties, the dual cross‐linked CEC‐OAHA‐MMP hydrogel holds significant potential for generating customizable gradient hydrogel constructs, to study and guide cellular responses to their microenvironment such as in tumor mimicking, tissue engineering, and stem cell differentiation and morphogenesis.
A Plant‐Transpiration‐Process‐Inspired Strategy for Highly Efficient Solar Evaporation
Authors: Wu Xuan , Chen George Y. , Zhang Wei , Liu Xiaokong , Xu Haolan
Published: May 2017

The conversion of solar energy into heat for solar steam generation is significant for energy saving and clean water supply. Recent advances in the design and application of photothermal‐based water‐evaporation systems have attracted intense research interest. However, it is imperative to develop a low‐cost and scalable photothermal system with further improved energy conversion efficiency to meet the demand for real‐world applications. Inspired by the natural transpiration process of plants, a wood‐polydopamine‐based photothermal material is developed for solar‐steam generation. Both the wood and polydopamine (PDA) derived from natural products are cost‐effective, biodegradable, and environmentally friendly. The wood–PDA system evaporates thin water film right above the bulk water surface, leading to extremely high efficiencies. Solar steam can be generated only 5 s after light irradiation. The solar‐steam generation efficiency reaches 87% under 1.0 sun. More significantly, an explosive evaporation which bypasses the phase change from liquid to gas is observed on the wood surface under irradiation of more‐intense light. This yields a solar‐steam generation efficiency (calculated by the classic equation) beyond 100% (e.g., 135% under 3.5 sun). It is envisioned that this strategy can be readily applied in practical solar‐evaporation applications due to its simplicity, low cost, and high efficiency.
Improving Thermoelectric Performance of α‐MgAgSb by Theoretical Band Engineering Design
Authors: Tan Xiaojian , Wang Ling , Shao Hezhu , Yue Song , Xu Jingtao , Liu Guoqiang , Jiang Haochuan , Jiang Jun
Published: May 2017

α‐MgAgSb is recently discovered to be a new class of thermoelectric material near room temperature. A competitive ZT of 1.4 at 525 K is achieved in Ni‐doped α‐MgAgSb, and the measured efficiency of energy conversion reaches a record value of 8.5%, which is even higher than that of the commercially applied material bismuth telluride. On the other hand, the band structure of α‐MgAgSb is believed to be unprofitable to the power factor, owing to the less degenerate valence valleys. Here, this paper reports a systematic theoretical study on the thermoelectric properties by using the electron/phonon structure and transport calculations. Based on the careful analysis of Fermi surface, a principled scheme is presented to design band engineering in α‐MgAgSb. Following the given rules, several effective dopants are predicted. As two examples, Zn‐ and Pd‐doped α‐MgAgSb are numerically confirmed to exhibit an extraordinary ZT value of 2.0 at 575 K and a high conversion efficiency of 12.6%, owing to the effects of band convergence. This work develops an applicable scheme for the purposive design of band engineering, and the idea can be simply applied to more thermoelectric materials.
Subtle Roles of Sb and S in Regulating the Thermoelectric Properties of N‐Type PbTe to High Performance
Authors: Tan Gangjian , Stoumpos Constantinos C. , Wang Si , Bailey Trevor P. , Zhao Li‐Dong , Uher Ctirad , Kanatzidis Mercouri G.
Published: May 2017

A high ZT (thermoelectric figure of merit) of ≈1.4 at 900 K for n‐type PbTe is reported, through modifying its electrical and thermal properties by incorporating Sb and S, respectively. Sb is confirmed to be an amphoteric dopant in PbTe, filling Te vacancies at low doping levels (<1%), exceeding which it enters into Pb sites. It is found that Sb‐doped PbTe exhibits much higher carrier mobility than similar Bi‐doped materials, and accordingly, delivers higher power factors and superior ZT. The enhanced electronic transport is attributed to the elimination of Te vacancies, which appear to strongly scatter n‐type charge carriers. Building on this result, the ZT of Pb0.9875Sb0.0125Te is further enhanced by alloying S into the Te sublattice. The introduction of S opens the bandgap of PbTe, which suppresses bipolar conduction while simultaneously increasing the electron concentration and electrical conductivity. Furthermore, it introduces point defects and induces second phase nanostructuring, which lowers the lattice thermal conductivity to ≈0.5 W m−1 K−1 at 900 K, making this material a robust candidate for high‐temperature (500–900 K) thermoelectric applications. It is anticipated that the insights provided here will be an important addition to the growing arsenal of strategies for optimizing the performance of thermoelectric materials.
Identifying the Real Minority Carrier Lifetime in Nonideal Semiconductors: A Case Study of Kesterite Materials
Authors: Hages Charles J. , Redinger Alex , Levcenko Sergiu , Hempel Hannes , Koeper Mark J. , Agrawal Rakesh , Greiner Dieter , Kaufmann Christian A. , Unold Thomas
Published: May 2017

Time‐resolved photoluminescence (TRPL) is a powerful characterization technique to study carrier dynamics and quantify absorber quality in semiconductors. The minority carrier lifetime, which is critically important for high‐performance solar cells, is often derived from TRPL analysis. However, here it is shown that various nonideal absorber properties can dominate the TRPL signal making reliable extraction of the minority carrier lifetime not possible. Through high‐resolution intensity‐, temperature‐, voltage‐dependent, and spectrally resolved TRPL measurements on absorbers and devices it is shown that photoluminescence (PL) decay times for kesterite materials are dominated by minority carrier detrapping. Therefore, PL decay times do not correspond to the minority carrier lifetime for these materials. The lifetimes measured here are on the order of hundreds of picoseconds in contrast to the nanosecond lifetimes suggested by the decay curves. These results are supported with additional measurements, device simulation, and comparison with recombination limited PL decays measured on Cu(In,Ga)Se2. The kesterite material system is used as a case study to demonstrate the general analysis of TRPL data in the limit of various measurement conditions and nonideal absorber properties. The data indicate that the current bottleneck for kesterite solar cells is the minority carrier lifetime.
Crosslinked Semiconductor Polymers for Photovoltaic Applications
Authors: Kahle Frank‐Julian , Saller Christina , Köhler Anna , Strohriegl Peter
Published: May 2017

Organic solar cells (OSCs) have achieved much attention and meanwhile reach efficiencies above 10%. One problem yet to be solved is the lack of long term stability. Crosslinking is presented as a tool to increase the stability of OSCs. A number of materials used for the crosslinking of bulk heterojunction cells are presented. These include the crosslinking of low bandgap polymers used as donors in bulk heterojunction cells, as well as the crosslinking of fullerene acceptors and crosslinking between donor and acceptor. External crosslinkers often based on multifunctional azides are also discussed. In the second part, some work either leading to OSCs with high efficiencies or giving insight into the chemistry and physics of crosslinking are highlighted. The diffusion of low molar mass fullerenes in a crosslinked matrix of a conjugated polymer and the influence of crosslinking on the carrier mobility is discussed. Finally, the use of crosslinking to make stable interlayers and the solution processing of multilayer OSCs are discussed in addition to presentation of a novel approach to stabilize nanoimprinted patterns for OSCs by crosslinking.
Electrochemical Energy Storage with a Reversible Nonaqueous Room‐Temperature Aluminum–Sulfur Chemistry
Authors: Yu Xingwen , Manthiram Arumugam
Published: May 2017

A reversible room‐temperature aluminum–sulfur (Al‐S) battery is demonstrated with a strategically designed cathode structure and an ionic liquid electrolyte. Discharge–charge mechanism of the Al‐S battery is proposed based on a sequence of electrochemical, microscopic, and spectroscopic analyses. The electrochemical process of the Al‐S battery involves the formation of a series of polysulfides and sulfide. The high‐order polysulfides (Sx2−, x ≥ 6) are soluble in the ionic liquid electrolyte. Electrochemical transitions between S62− and the insoluble low‐order polysulfides or sulfide (Sx2−, 1 ≤ x < 6) are reversible. A single‐wall carbon nanotube coating applied to the battery separator helps alleviate the diffusion of the polysulfide species and reduces the polarization behavior of the Al‐S batteries.
Hydrogenated Core–Shell MAX@K2Ti8O17 Pseudocapacitance with Ultrafast Sodium Storage and Long‐Term Cycling
Authors: Zou Guodong , Guo Jianxin , Liu Xianyu , Zhang Qingrui , Huang Gang , Fernandez Carlos , Peng Qiuming
Published: May 2017

Sodium‐ion batteries are considered alternatives to lithium‐ion batteries for energy storage devices due to their competitive cost and source abundance. However, the development of electrode materials with long‐term stability and high capacity remains a great challenge. Here, this paper describes for the first time the synthesis of a new class of core–shell MAX@K2Ti8O17 by alkaline hydrothermal reaction and hydrogenation of MAX, which grants high sodium ion‐intercalation pseudocapacitance. This composite electrode displays extraordinary reversible capacities of 190 mA h g−1 at 200 mA g−1 (0.9 C, theoretical value of ≈219 mA h g−1) and 150 mA h g−1 at 1000 mA g−1 (4.6 C). More importantly, a reversible capacity of 75 mA h g−1 at 10 000 mA g−1 (46 C) is retained without any apparent capacity decay even after more than 10 000 cycles. Experimental tests and first‐principle calculations confirm that the increase in Ti3+ on the surface layers of MAX@K2Ti8O17 by hydrogenation increases its conductivity in addition to enhancing the sodium‐ion intercalation pseudocapacitive process. Furthermore, the distorted dodecahedrons between Ti and O layers not only provide abundant sites for sodium‐ion accommodation but also act as wide tunnels for sodium‐ion transport.
High‐Temperature Treatment of Li‐Rich Cathode Materials with Ammonia: Improved Capacity and Mean Voltage Stability during Cycling
Authors: Erickson Evan M. , Sclar Hadar , Schipper Florian , Liu Jing , Tian Ruiyuan , Ghanty Chandan , Burstein Larisa , Leifer Nicole , Grinblat Judith , Talianker Michael , Shin Ji‐Yong , Lampert Jordan K. , Markovsky Boris , Frenkel Anatoly I. , Aurbach Doron
Published: May 2017

Li‐rich electrode materials of the family xLi2MnO3·(1−x)LiNiaCobMncO2 (a + b + c = 1) suffer a voltage fade upon cycling that limits their utilization in commercial batteries despite their extremely high discharge capacity, ≈250 mA h g−1. Li‐rich, 0.35Li2MnO3·0.65LiNi0.35Mn0.45Co0.20O2, is exposed to NH3 at 400 °C, producing materials with improved characteristics: enhanced electrode capacity and a limited average voltage fade during 100 cycles in half cells versus Li. Three main changes caused by NH3 treatment are established. First, a general bulk reduction of Co and Mn is observed via X‐ray photoelectron spectroscopy and X‐ray absorption near edge structure. Next, a structural rearrangement lowers the coordination number of CoO and MnO bonds, as well as formation of a surface spinel‐like structure. Additionally, Li+ removal from the bulk causes the formation of surface LiOH, Li2CO3, and Li2O. These structural and surface changes can enhance the voltage and capacity stability of the Li‐rich material electrodes after moderate NH3 treatment times of 1–2 h.
Particle‐laden liquid jet impingement on a moving substrate
Authors: Rahmani Hatef , Green Sheldon I.
Published: May 2017

The impingement of high speed jets on a moving surface was studied. The jet fluids were dilute suspensions of neutrally buoyant particles in water–glycerin solutions. At these low particle concentrations, the suspensions have Newtonian fluid viscosity. A variety of jet and surface velocities, solution properties, nozzle diameters, mean particle sizes, and volume fractions were studied. For each case the splash‐deposition threshold was quantified. It was observed that for jets with very small particles, addition of solids to the jet enhances deposition and postpones splash relative to a particle‐free water–glycerin solution with the same viscosity. In contrast, jets with larger particles in suspension were more prone to splash than single phase jets of the same viscosity. It is speculated that the change in character of the splash response for the jets with larger particles in suspension occurs when the particle diameter is comparable to the lamella thickness. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4673–4684, 2017
Indirect conduction in gas–solids systems: Static vs. Dynamic effects
Authors: Lattanzi Aaron M. , Hrenya Christine M.
Published: May 2017

Conductive mechanisms play an integral role in the transfer of heat through dense gas–solid systems. In particular, the conduction occurring through a thin layer of fluid between the solids (indirect) can become the primary mode for heat transfer within gas–solid systems. However, attempts to evaluate the effect of surface roughness and fluid lens thickness (theoretical inputs) on indirect conduction have been restricted to static, single‐particle cases. By contrast, here we quantify these effects for dynamic, multi‐particle systems using a non‐dimensional, average heat transfer coefficient that is obtained via techniques commonly employed by classic kinetic theory. Analytical predictions for the impact of theoretical inputs on indirect conduction are compared to outputs from computational fluid dynamics–discrete element method simulations. The analytical predictions are in agreement with simulations and show that indirect conduction in static systems is most sensitive to surface roughness, while dynamic systems are sensitive to the fluid lens thickness. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4685–4693, 2017
Renal anomalies and lymphedema distichiasis syndrome. A rare association?
Authors: Jones Gabriela E. , Richmond Anna K. , Navti Osric , Mousa Hatem A. , Abbs Stephen , Thompson Edward , Mansour Sahar , Vasudevan Pradeep C.
Published: May 2017

Lymphedema distichiasis syndrome (LDS) is a rare, autosomal dominant genetic condition, characterized by lower limb lymphedema and distichiasis. Other associated features that have been reported include varicose veins, cleft palate, congenital heart defects, and ptosis. We update a previously reported family with a pathogenic variant in FOXC2 (c.412‐413insT) where five affected individuals from the youngest generation had congenital renal anomalies detected on prenatal ultrasound scan. These included four fetuses with hydronephrosis and one with bilateral renal agenesis. A further child with LDS had prominence of the left renal pelvis on postnatal renal ultrasound. We also describe a second family in whom the proband and his affected son had congenital renal anomalies; left ectopic kidney, right duplex kidney, and bilateral duplex collecting systems with partial duplex kidney with mild degree of malrotation, respectively. Foxc2 is expressed in the developing kidney and therefore congenital renal anomalies may well be associated, potentially as a low penetrance feature. We propose that all individuals diagnosed with LDS should have a baseline renal ultrasound scan at diagnosis. It would also be important to consider the possibility of renal anomalies during prenatal ultrasound of at risk pregnancies, and that the presence of hydronephrosis may be an indication that the baby is affected with LDS.
Enantioselective Construction of All‐Carbon Quaternary Stereogenic Centers by Using Phosphine Catalysis
Authors: Li Huilin , Lu Yixin
Published: May 2017

The asymmetric construction of all‐carbon quaternary stereogenic centers represents one of the most‐challenging tasks in organic synthesis, and it has drawn continuous attention from the synthetic community. Asymmetric phosphine catalysis has progressed at an astonishingly rate over the past decade and it offers the efficient creation of a diverse range of structural architectures. In this Focus Review, synthetic methods based on phosphine catalysis for the enantioselective construction of all‐carbon quaternary stereogenic centers are highlighted.
Acute impact of continuous positive airway pressure on nasal patency
Authors: Balsalobre Leonardo , Pezato Rogério , Gasparini Hiran , Haddad Fernanda , Gregório Luis Carlos , Fujita Reginaldo R
Published: May 2017

Background

Continuous airflow in the upper airway can cause discomfort, leading to nasopharyngeal complaints. The aim of the present study is to evaluate the acute effects of continuous positive upper‐airway pressure on nasal patency in awake normal subjects.

Methods

Twenty‐seven adults (17 men; 10 women; age range, 18 to 43 years) were exposed to continuous airway pressure (20 cmH2O) in the nasal cavity, delivered by a continuous positive airway pressure (CPAP) device through a nasal mask for 2 hours. Visual analogue scale (VAS) of nasal obstruction, Nasal Obstruction Symptom Evaluation (NOSE) modified scale, acoustic rhinometry (AR), and peak nasal inspiratory flow (PF) were measured before and after the use of CPAP.

Results

There was an increase in nasal obstruction scores both on the VAS (p < 0.05) and on the NOSE scale (p < 0.05), as well as a reduction in nasal cavity volume on AR (p < 0.05) and a decline in PF (p < 0.05). Subjects were stratified into 2 groups: with and without symptoms of allergic rhinitis. Nasal parameters were significantly worse in the rhinitis group, with higher nasal obstruction scores on the VAS (p = 0.001) and NOSE scale (p < 0.001) and decreased PF (p < 0.001).

Conclusion

Acute exposure to positive pressure via CPAP is associated with subjective and objective reductions in nasal patency. In individuals with allergic nasal symptoms, deterioration is even more severe than in patients without these symptoms.
Effects of ophthalmologic solutions on sinonasal ciliated epithelium
Authors: Workman Alan D. , Carey Ryan M. , Kohanski Michael A. , Adappa Nithin D. , Palmer James N. , Cohen Noam A.
Published: May 2017

Background

Off‐label use of topical ophthalmologic formulations for treatment of rhinologic disease is cited in recent literature and is anecdotally prevalent among practicing otolaryngologists. Steroids, antibiotics, and other drugs designed for ocular use have subjective clinical efficacy in the nose and sinuses, but their specific effects on the ciliated epithelium are less well defined. This study examines 9 commercially available ophthalmologic drug formulations for effects on ciliary motility in sinonasal cultures, in an effort to characterize their utility as topical therapies for sinonasal diseases.

Methods

Ophthalmologic solutions were tested on human sinonasal cultures grown at an air‐liquid interface. Baseline ciliary beat frequency (CBF) was recorded and compared with CBF changes in the 20 minutes after drug addition. Substances were categorized by degree of ciliostimulation or cilioinhibition.

Results

All ophthalmologic solutions tested had only moderate effects on CBF during the 20‐minute experimental period, with no solutions causing overt ciliostasis. Azithromycin, neomycin, and olopatadine were slightly ciliostimulatory, whereas levofloxacin, tobramycin, dexamethasone, azelastine, and prednisolone acetate were cilioinhibitory. Ciprofloxacin elicited moderate cilioinhibition that progressed to ciliostimulation.

Conclusion

All solutions tested appear to have moderate effects on ciliated cell surfaces for a period of time typical of mucociliary clearance (10 to 20 minutes). Both active drugs and excipients can play a role in ciliary modulation, and specific formulations can show unique or unexpected properties. Any other individual ophthalmologic solutions to be used in a nasal drug delivery system should be tested in this manner to evaluate potential ciliary effects before clinical use.
Chronic sinonasal tract inflammation as a precursor to nasopharyngeal carcinoma and sinonasal malignancy in the United States
Authors: Wu Eric L. , Riley Charles A. , Hsieh Mei‐Chin , Marino Michael J. , Wu Xiao‐Cheng , McCoul Edward D.
Published: May 2017

Background

Chronic inflammatory states have been linked to the development of malignancy. Chronic rhinosinusitis (CRS) and allergic rhinitis (AR) have been associated with nasopharyngeal carcinoma (NPC) in population‐based studies in Asia. A similar association with NPC and paranasal sinus malignancy (PSM) has not been defined in a North American population. Our purpose was to investigate the impact of CRS and AR on the risk of NPC and PSM.

Methods

The Surveillance, Epidemiology, and End Results (SEER)–Medicare linked database was queried as a case‐control study of adults ≥65 years of age. The study cohort included 2009 patients diagnosed with NPC and/or PSM diagnosed between 2003 and 2011, and 2009 propensity‐score‐matched controls selected from a 5% random sample of Medicare beneficiaries without cancer. CRS and AR were examined as exposures. Multivariable unconditional logistic regression was employed.

Results

Overall, NPC and PSM patients were more likely to have previous CRS diagnosis than the controls (9.2% vs 3.0% and 11.1% vs 2.7%, respectively). CRS was associated with greater odds of developing NPC (odds ratio [OR], 3.51; 95% confidence interval [CI], 2.12‐5.79) and PSM (OR, 5.30; 95% CI, 3.55‐7.92). AR was associated with greater odds of developing NPC (OR, 4.23; 95% CI, 2.96 to 6.06) and PSM (OR, 3.35; 95% CI, 2.49‐4.49). The number needed to harm in the exposed population was 311.

Conclusions

CRS and AR are associated with the presence of NPC and PSM in the elderly population of United States. This epidemiologic association will need to be examined for causative pathophysiologic mechanisms and utility in clinical diagnosis.