bluuebunny/crossref_metadata_2025 huggingface dataset:
A self‐similar scaling for cross‐shelf exchange driven by transient rip currents
Authors: Suanda Sutara H. , Feddersen Falk
Published: June 2015

Transient rip currents, episodic offshore flows from the surf zone to the inner shelf, present a recreational beach hazard and exchange material across the nearshore ocean. The magnitude and offshore extent of transient rip‐current‐induced exchange and its relative importance to other inner shelf exchange processes are poorly understood. Here 120 model simulations with random, normally incident, directionally spread waves spanning a range of beach slopes and wave conditions show that the transient rip current exchange velocity is self‐similar. The nondimensional exchange velocity, surf zone flushing time, and cross‐shore decay length scale are scaled by beach slope and wave properties, depending strongly on wave directional spread. Transient rip‐current‐driven exchange can be compared to other cross‐shelf exchange processes. For example, transient rip‐current‐driven exchange is stronger than wave‐induced Stokes‐drift‐driven exchange up to six surf zone widths from shore.
Abrupt changes in Indian summer monsoon strength during 33,800 to 5500 years B.P.
Authors: Dutt Som , Gupta Anil K. , Clemens Steven C. , Cheng Hai , Singh Raj K. , Kathayat Gayatri , Edwards R. Lawrence
Published: June 2015

Speleothem proxy records from northeastern (NE) India reflect seasonal changes in Indian summer monsoon strength as well as moisture source and transport paths. We have analyzed a new speleothem record from Mawmluh Cave, Meghalaya, India, in order to better understand these processes. The data show a strong wet phase 33,500–32,500 years B.P. followed by a weak/dry phase from 26,000 to 23,500 years B.P. and a very weak phase from 17,000 to 15,000 years B.P. The record suggests abrupt increase in strength during the Bølling‐Allerød and early Holocene periods and pronounced weakening during the Heinrich and Younger Dryas cold events. We infer that these changes in monsoon strength are driven by changes in temperature gradients which drive changes in winds and moisture transport into northeast India.
Fractal patterns in riverbed morphology produce fractal scaling of water storage times
Authors: Aubeneau A. F. , Martin R. L. , Bolster D. , Schumer R. , Jerolmack D. , Packman A.
Published: June 2015

River topography is famously fractal, and the fractality of the sediment bed surface can produce scaling in solute residence time distributions. Empirical evidence showing the relationship between fractal bed topography and scaling of hyporheic travel times is still lacking. We performed experiments to make high‐resolution observations of streambed topography and solute transport over naturally formed sand bedforms in a large laboratory flume. We analyzed the results using both numerical and theoretical models. We found that fractal properties of the bed topography do indeed affect solute residence time distributions. Overall, our experimental, numerical, and theoretical results provide evidence for a coupling between the sand‐bed topography and the anomalous transport scaling in rivers. Larger bedforms induced greater hyporheic exchange and faster pore water turnover relative to smaller bedforms, suggesting that the structure of legacy morphology may be more important to solute and contaminant transport in streams and rivers than previously recognized.
A subsurface structure change associated with the eruptive activity at Sakurajima Volcano, Japan, inferred from an accurately controlled source
Authors: Maeda Yuta , Yamaoka Koshun , Miyamachi Hiroki , Watanabe Toshiki , Kunitomo Takahiro , Ikuta Ryoya , Yakiwara Hiroshi , Iguchi Masato
Published: June 2015

Temporal variations of Green functions associated with the eruptive activity at Sakurajima Volcano, Japan, were estimated using an accurately controlled routinely operated signal system (ACROSS). We deconvolved 400 s waveforms of the ACROSS signal at nearby stations by a known source time function and stacked the results based on the time relative to individual eruptions and the eruption intervals; the quantities obtained by this procedure are Green functions corresponding to various stages of the eruptive activity. We found an energy decrease in the later phase of the Green functions in active eruptive periods. This energy decrease, localized in the 2–6 s window of the Green functions, is difficult to explain by contamination from volcanic earthquakes and tremors. The decrease could be more reasonably attributed to a subsurface structure change caused by the volcanic activity.
First images of thunder: Acoustic imaging of triggered lightning
Authors: Dayeh M. A. , Evans N. D. , Fuselier S. A. , Trevino J. , Ramaekers J. , Dwyer J. R. , Lucia R. , Rassoul H. K. , Kotovsky D. A. , Jordan D. M. , Uman M. A.
Published: June 2015

An acoustic camera comprising a linear microphone array is used to image the thunder signature of triggered lightning. Measurements were taken at the International Center for Lightning Research and Testing in Camp Blanding, FL, during the summer of 2014. The array was positioned in an end‐fire orientation thus enabling the peak acoustic reception pattern to be steered vertically with a frequency‐dependent spatial resolution. On 14 July 2014, a lightning event with nine return strokes was successfully triggered. We present the first acoustic images of individual return strokes at high frequencies (>1 kHz) and compare the acoustically inferred profile with optical images. We find (i) a strong correlation between the return stroke peak current and the radiated acoustic pressure and (ii) an acoustic signature from an M component current pulse with an unusual fast rise time. These results show that acoustic imaging enables clear identification and quantification of thunder sources as a function of lightning channel altitude.
Increase of the electric field in head‐on collisions between negative and positive streamers
Authors: Ihaddadene Mohand A. , Celestin Sebastien
Published: June 2015

Head‐on collisions between negative and positive streamer discharges have recently been suggested to be responsible for the production of high electric fields leading to X‐rays emissions. Using a plasma fluid approach, we model head‐on collisions between negative and positive streamers. We observe the occurrence of a very strong electric field at the location of the streamer collision. However, the enhancement of the field produces a strong increase in the electron density, which leads to a collapse of the field over only a few picoseconds. Using a Monte Carlo model, we have verified that this process is therefore not responsible for the acceleration of a significant number of electrons to energy >1 keV. We conclude that no significant X‐ray emission could be produced by the head‐on encounter of nonthermal streamer discharges. Moreover, we quantify the optical emissions produced in the streamer collision.
Impact of having realistic tropical cyclone frequency on ocean heat content and transport forecasts in a high‐resolution coupled model
Authors: Zhang S. , Zhao M. , Lin S.‐J. , Yang X. , Anderson W. , Zhang W. , Rosati A. , Underwood S. , Zeng F.
Published: June 2015

This study examines two sets of high‐resolution coupled model forecasts starting from no‐tropical cyclone (TC) and correct‐TC‐statistics initial conditions to understand the role of TC events on climate prediction. While the model with no‐TC initial conditions can quickly spin‐up TCs within a week, the initial conditions with a corrected TC distribution can produce more accurate forecast of sea surface temperature up to 1.5 months and maintain larger ocean heat content up to 6 months due to enhanced mixing from continuous interactions between initialized and forecasted TCs and the evolving ocean states. The TC‐enhanced tropical ocean mixing strengthens the meridional heat transport in the Southern Hemisphere driven primarily by Southern Ocean surface Ekman fluxes but weakens the Northern Hemisphere poleward transport in this model. This study suggests a future plausible initialization procedure for seamless weather‐climate prediction when individual convection‐permitting cyclone initialization is incorporated into this TC‐statistics‐permitting framework.
On the correlation between the fast solar wind flow changes and substorm occurrence
Authors: Semenov V. S. , Kubyshkina D. I. , Kubyshkina M. V. , Kubyshkin I. V. , Partamies N.
Published: June 2015

There is a point of view that solar wind factors, which break the magnetotail symmetry, are more effective in triggering the magnetospheric substorm. To clarify the question we use a database of substorm onsets and found the evident dependence of the substorm probability on the solar wind flow direction jumps (asymmetric factor), while distribution of the substorm occurrence on the solar wind number density jumps (symmetric factor) is homogeneous. The theoretical interpretation is based on the extension of the existing symmetric Kan model for a bent current sheet. Allowing the model tilt angle to vary in time, we found that the induced electric field penetrates to the central region of the bent current sheet. If the solar wind direction jump increases the bending, then induced electric field thins the current sheet and thus stimulates the reconnection. In the opposite case the current sheet thickens. We claim that this effect is sufficient (provides twice or more thinning of the current sheet in 10 min).
High‐latitude thermospheric wind observations and simulations with SuperDARN data driven NCAR TIEGCM during the December 2006 magnetic storm
Authors: Wu Qian , Emery B. A. , Shepherd S. G. , Ruohoniemi J. Michael , Frissell N. A , Semeter J.
Published: June 2015

Ion convection pattern derived from the Super Dual Auroral Radar Network potential pattern (SDP) data is developed for the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamic General Circulation Model. The December 2006 geomagnetic storm event was simulated with the SDP ion convection pattern and two other existing input options (Heelis and Weimer convection models). The high‐latitude thermospheric wind simulated with SDP showed very good agreement with the Fabry‐Perot interferometer thermospheric wind data inside the polar cap at Resolute, Canada (74.7°N, 94.8°W, magnetic latitude 84). The Heelis model overestimated the winds during the storm event, because the model does not consider the cross polar cap potential saturation at high global geomagnetic index (Kp) values. The Weimer model provides a better performance than the Heelis model in this case. However, it has a larger discrepancy compared to the SDP results. The SDP provides an alternative data‐based tool for study of the ionosphere/thermosphere interactions in the polar cap.
Low‐energy ion precipitation structures associated with pulsating auroral patches
Authors: Liang Jun , Donovan E. , Nishimura Y. , Yang B. , Spanswick E. , Asamura K. , Sakanoi T. , Evans D. , Redmon R.
Published: June 2015

Pulsating auroras often appear in forms of geo‐stable or slowly convecting “patches.” These patches can maintain their rough shape and size over many sequences of luminosity pulsations, yet they slowly drift with ionospheric E × B convection. Because of these characteristics, there has long been a speculation that the pulsating auroral patch (PAP) is connected to flux tubes filled with enhanced cold plasma. In this study, we perform a survey on pulsating auroral events when the footprints of low‐Earth‐orbit satellites traversed the PAPs, with a focus on the low‐energy particle signatures associated with the PAPs. As a result, we identified, in a majority (~2/3) of events, the existence of a low‐energy ion precipitation structure that is collocated with the PAP, with core energies ranging from several tens of eV up to a few hundred eV. This result supports the hypothesis that a PAP connects to flux tubes filled with enhanced cold plasma. We further propose that the plasma outflows from the ionosphere are the origin of such cold plasma flux tubes. We suggest that the PAP is formed by a combination of high‐energy electrons of a magnetospheric origin, the low‐energy plasma structure of an ionospheric origin, and certain ELF/VLF waves that are intensified and modulated in interactions with both the hot and cold plasma populations.
A microbial functional group‐based module for simulating methane production and consumption: Application to an incubated permafrost soil
Authors: Xu Xiaofeng , Elias Dwayne A. , Graham David E. , Phelps Tommy J. , Carroll Sue L. , Wullschleger Stan D. , Thornton Peter E.
Published: June 2015

Accurately estimating methane (CH4) flux in terrestrial ecosystems is critically important for investigating and predicting biogeochemistry‐climate feedbacks. Improved simulations of CH4 flux require explicit representations of the microbial processes that account for CH4 dynamics. A microbial functional group‐based module was developed, building on the decomposition subroutine of the Community Land Model 4.5. This module considers four key mechanisms for CH4 production and consumption: methanogenesis from acetate or from single‐carbon compounds and CH4 oxidation using molecular oxygen or other inorganic electron acceptors. Four microbial functional groups perform these processes: acetoclastic methanogens, hydrogenotrophic methanogens, aerobic methanotrophs, and anaerobic methanotrophs. This module was used to simulate dynamics of carbon dioxide (CO2) and CH4 concentrations from an incubation experiment with permafrost soils. The results show that the model captures the dynamics of CO2 and CH4 concentrations in microcosms with top soils, mineral layer soils, and permafrost soils under natural and saturated moisture conditions and three temperature conditions of −2°C, 3°C, and 5°C (R2 > 0.67; P < 0.001). The biases for modeled results are less than 30% across the soil samples and moisture and temperature conditions. Sensitivity analysis confirmed the importance of acetic acid's direct contribution as substrate and indirect effects through pH feedback on CO2 and CH4 production and consumption. This study suggests that representing the microbial mechanisms is critical for modeling CH4 production and consumption; it is urgent to incorporate microbial mechanisms into Earth system models for better predicting trace gas dynamics and the behavior of the climate system.
On the assessment of aridity with changes in atmospheric CO2
Authors: Roderick Michael L. , Greve Peter , Farquhar Graham D.
Published: June 2015

A recent interpretation of climate model projections concluded that “warmer is more arid.” In contrast, dust records and other evidence have led the geoscience community to conclude that “warmer is less arid” leading to an aridity paradox. The “warmer is more arid” interpretation is based on a projected increase in the vapour pressure deficit (∼ 7–9% K−1) that results in a projected increase in potential evaporation that greatly exceeds the projected increase in precipitation. However, the increase in potential evaporation does not result in an increase in (actual) evaporation which remains more or less constant in the model output. Projected changes in the long‐term aridity can be assessed by directly interrogating the climate model output. To that end, we equate lack of precipitation with meteorological aridity and lack of runoff with hydrologic aridity. A third perspective, agro‐ecological aridity, is not directly related to the water lost but rather to the carbon gain and is equated with the reduction in photosynthetic uptake of CO2. We reexamine the same climate model output and conclude that “warmer is less arid” from all perspectives and in agreement with the geological records. Future research will need to add the critical regional and seasonal perspectives to the aridity assessments described here.
State‐of‐the‐Art Research into Multimedia Learning: A Commentary on Mayer's Handbook of Multimedia Learning
Authors: Ayres Paul
Published: June 2015

This article reviews the research into multimedia learning through the lens of a recently updated Handbook of Multimedia Learning edited by Richard Mayer. By examining the theories underpinning the research and the major experimental findings, a number of conclusions emerged. Firstly, the major theories and models guiding the research are well accepted and based on classical memory research, although there is a need to extend them to the affective domain. Secondly, most of the boundary conditions for effective learning from basic multimedia materials (e.g. explanatory words and pictures) have been identified. Thirdly, for more complex learning environments (e.g. games and computer‐based tutors), much less is known, and more research is required to untangle the various moderating factors. Fourthly, there is a need for further investigations that match specific instructional strategies (e.g. self‐explanations) with multimedia materials to find the most effective learning combination. Copyright © 2015 John Wiley & Sons, Ltd.
Mesoporous Carbon Nanocube Architecture for High‐Performance Lithium–Oxygen Batteries
Authors: Sun Bing , Chen Shuangqiang , Liu Hao , Wang Guoxiu
Published: June 2015

One of the major challenges to develop high‐performance lithium–oxygen (Li–O2) battery is to find effective cathode catalysts and design porous architecture for the promotion of both oxygen reduction reactions and oxygen evolution reactions. Herein, the synthesis of mesoporous carbon nanocubes as a new cathode nanoarchitecture for Li–O2 batteries is reported. The oxygen electrodes made of mesoporous carbon nanocubes contain numerously hierarchical mesopores and macropores, which can facilitate oxygen diffusion and electrolyte impregnation throughout the electrode, and provide sufficient spaces to accommodate insoluble discharge products. When they are applied as cathode catalysts, the Li–O2 cells deliver discharge capacities of 26 100 mA h g−1 at 200 mA g−1, which is much higher than that of commercial carbon black catalysts. Furthermore, the mesoporous nanocube architecture can also serve as a conductive host structure for other highly efficient catalysts. For instance, the Ru functionalized mesoporous carbon nanocubes show excellent catalytic activities toward oxygen evolution reactions. Li–O2 batteries with Ru functionalized mesoporous carbon nanocube catalysts demonstrate a high charge/discharge electrical energy efficiency of 86.2% at 200 mA g−1 under voltage limitation and a good cycling performance up to 120 cycles at 400 mA g−1 with the curtaining capacity of 1000 mA h g−1.
“Layer‐Filter Threshold” Technique for Near‐Infrared Laser Ablation in Organic Semiconductor Device Processing
Authors: Ye Feng , Chen Zhaobin , Zhao Xiaoli , Chen Jiayue , Yang Xiaoniu
Published: June 2015

Although conventional laser ablation (CLA) method has widely been used in patterning of organic semiconductor thin films, its quality control still remains unsatisfied due to the ambiguous photochemical and photothermal processes. Based on industrial available near‐infrared laser source, herein, a novel “layer‐filter threshold” (LFT) technique is proposed, which involves the decomposition of targeted “layer‐filter” and subsequent explosive evaporation process to purge away the upper layers instead of layer‐by‐layer ablation. For photovoltaic device with structure of metal/blend/PEDOT:PSS/ITO/glass, the PEDOT:PSS layer as the “layer‐filter” is first demonstrated to be effective, and then the merged P1–P2 line and metal electrode layer are readily patterned through the “self‐aligned” effect and regulation of ablation direction, respectively. The correlation between laser fluence and explosive ablation efficacy is also investigated. Finally, photovoltaic modules based on classical P3HT:PC61BM and low‐bandgap PBDT‐TFQ:PC71BM systems are separately fabricated following the LFT technique. It is found that over 90% of geometric fill factor is achieved while device performances maintain in a limited change with increased number of series cells. In comparison to conventional laser ablation methods, the LFT technique does not require sophisticated instruments but reaches comparable processing accuracy, which shows promising potential in the fabrication and commercialization of organic semiconductor thin‐film devices.
Understanding the Enhancement Mechanisms of Surface Plasmon‐Mediated Photoelectrochemical Electrodes: A Case Study on Au Nanoparticle Decorated TiO2 Nanotubes
Authors: Xu Zhen , Lin Yinyue , Yin Min , Zhang Haifeng , Cheng Chuanwei , Lu Linfeng , Xue Xinzhong , Fan Hong Jin , Chen Xiaoyuan , Li Dongdong
Published: June 2015

Surface plasmon resonance (SPR) enhancement in photocatalyst and photovoltaics has been widely studied and different enhancement mechanisms have been established based on different heterostructure interface configurations. This work is intended to unveil the mechanisms behind charge or energy transfer in different plasmonic configurations of metal particle–semiconductor interfaces, especially with a dielectric layer. For this purpose, a series of composite photoelectrodes based on anodic TiO2 nanotube (TONT) backbones coated with Au, Al2O3, or both are designed and characterized systematically. In conjunction with both experimental measurements and numerical simulations, it is revealed that in the TONT‐Al2O3‐Au electrode system (i.e., a thin nonconductive spacer between semiconductor and metal), the enhancement is dominantly governed by SPR‐mediated hot‐electron injection rather than conventional‐thought near‐field electromagnetic enhancement. Among all configurations, the TONT‐Au‐Al2O3 electrode shows the best photoresponse in both UV and visible regions. The superior visible light response of the TONT‐Au‐Al2O3 electrode is ascribed to the Al2O3 intensified local electromagnetic field that enhances the hot‐electron injection through the TiO2‐Au interface, and an effective surface passivation by the Al2O3 coating.
Synergistic Flame‐Retardant Effect of IFR and PPO in Improving Flame Retardancy of Polystyrene
Authors: Yan Hong , Zhang Jinkai , Zhang Meng , Du Xiangxiang , Ma Senyuan , Xu Bingshe
Published: June 2015

Intumescent flame retardant (IFR) and polyphenylene oxide (PPO) were used together to enhance the flame‐retardant performance of polystyrene (PS). The IFR system was composed of melamine, ammonium polyphosphate, and pentaerythritol. The results showed that IFR and PPO have a synergistic effect on the flame‐retardant performance of PS. Moreover, the TGA data showed that PPO could promote PS to form more char with higher loading of IFR. Cone calorimeter tests indicated that only the condensed phase played a role in the flame retardancy of PS composites with one additive of IFR or PPO, whereas the flame‐retardant effect of PS composites loaded with PPO and IFR existed in the condensed and gaseous phases due to different char structures.
Non‐Hodgkin lymphoma subtype distribution, geodemographic patterns, and survival in the US: A longitudinal analysis of the National Cancer Data Base from 1998 to 2011
Authors: Al‐Hamadani Mohammed , Habermann Thomas M. , Cerhan James R. , Macon William R. , Maurer Matthew J. , Go Ronald S.
Published: June 2015

The World Health Organization classification of non‐Hodgkin lymphoma (NHL) was introduced in 2001. However, its incorporation into clinical practice is not well‐described. We studied the distribution of NHL subtypes in adults diagnosed from 1998 to 2011, evaluated time trends, geo‐demographic correlates, and changes in 5‐year overall survival (OS). We obtained data prospectively collected by the National Cancer Data Base, which covers 70% of US cancer cases. There were 596,476 patients diagnosed with NHL. The major subtypes were diffuse large B‐cell (32.5%), chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL; 18.6%), follicular (17.1%), marginal zone (8.3%), mantle cell (4.1%), peripheral T‐cell not‐otherwise‐specified (1.7%), Burkitt (1.6%), hairy cell (1.1%), lymphoplasmacytic (1.1%), and NHL not‐otherwise‐specified (10.8%). Over the study period, the proportion of NHL not‐otherwise‐specified declined by half, while marginal zone lymphoma doubled. The distribution of major and rare NHL subtypes varied according to demographics but less so geographically or by type of treatment facility. We noted several novel findings among Hispanics (lower proportion of CLL/SLL, but higher Burkitt lymphoma and nasal NK/T‐cell lymphoma), Asians (higher enteropathy‐associated T‐cell and angioimmunoblastic T‐cell lymphomas), Blacks (higher hepatosplenic T‐cell lymphoma), and Native Americans (similar proportions of CLL/SLL and nasal NK/T‐cell lymphoma as Asians). With the exception of peripheral T‐cell not‐otherwise‐specified and hairy cell leukemia, 5‐year OS has improved for all the major NHL subtypes. Am. J. Hematol. 90:790–795, 2015. © 2015 Wiley Periodicals, Inc.
A multicenter, phase II study of maintenance azacitidine in older patients with acute myeloid leukemia in complete remission after induction chemotherapy
Authors: Griffin Patrick T. , Komrokji Rami S. , De Castro Carlos M. , Rizzieri David A. , Melchert Magda , List Alan F. , Lancet Jeffrey E.
Published: June 2015

Older patients with acute myeloid leukemia (AML) have poor outcomes, with median durations of complete remission lasting less than 1 year. Increased toxicity in older patients limits the delivery of standard consolidation therapies, such as allogeneic stem cell transplant or high‐dose cytarabine. Azacitidine, a nucleoside analog/DNA methyltransferase inhibitor, has demonstrated significant activity and favorable tolerability in patients unable to tolerate intensive induction chemotherapy; however, the role of azacitidine in the maintenance setting has not been fully evaluated. We undertook a pilot study of low‐dose subcutaneous azacitidine [50 mg/(m2 day)] for 5 days every 4 weeks) in AML patients ≥60 years of age in first remission following standard induction therapy. The primary objective was to determine the 1‐year disease‐free survival (DFS); secondary objectives were to determine safety and tolerability. We enrolled 24 patients (median age 68, range 62–81 years), the majority of whom received anthracycline‐cytarabine induction regimens. From the time of first complete remission, the estimated 1‐year DFS was 50% and the median overall survival was 20.4 months. Thrombocytopenia and neutropenia were the most common grade 3/4 toxicities (50 and 58%, respectively). In our study population, maintenance therapy with subcutaneous azacitidine was safe and well tolerated. Am. J. Hematol. 90:796–799, 2015. © 2015 Wiley Periodicals, Inc.
Osteocalcin and type 2 diabetes risk in Latinos: A life course approach.
Authors: González‐García Zoe M. , Kullo Iftikhar J. , Coletta Dawn K. , Mandarino Lawrence J. , Shaibi Gabriel Q.
Published: June 2015

Objective

To examine associations between circulating levels of the bone‐derived protein osteocalcin (OC) and type 2 diabetes (T2D) risk in Latino children and adults.

Methods

Serum OC was measured in 136 children and 531 adults who had the following T2D risk factors assessed, body mass index (BMI), Hemoglobin A1c (HbA1c), fasting and 2‐hour glucose during an oral glucose tolerance test.

Results

OC was significantly higher in children than adults (209.0 ± 12.1 vs. 41.0 ± 0.9 ng/ml, p<0.0001). In adults, OC was inversely associated (all p<0.001) with BMI (r=‐0.2), HbA1c (r=‐0.2), fasting glucose (r=‐0.16), and 2‐hour glucose (r=‐0.21), while there were no significant associations in children. There was a stepwise decrease in OC with increasing dysglycemia in adults, normoglycemic (44.1 ± 1.3 ng/ml), prediabetic (39.3 ± 1.3 ng/ml), and T2D (31.8 ± 1.2 ng/ml), (p<0.0001), whereas there were no differences between normal and prediabetic youth (195.7 ± 16.1 vs. 194.7 ± 25.8 ng/ml, p=0.3).

Conclusions

OC was inversely associated with T2D risk in Latino adults; however, this pattern was not observed in children. Am. J. Hum. Biol. 27:859–861, 2015. © 2015 Wiley Periodicals, Inc.
High‐protein meal challenge reveals the association between the salivary cortisol response and metabolic syndrome in police officers
Authors: Baughman Penelope , Andrew Michael E. , Burchfiel Cecil M. , Fekedulegn Desta , Hartley Tara A. , Violanti John M. , Miller Diane B.
Published: June 2015

Objectives

Policing is considered a high‐stress occupation and officers have elevated cardiovascular morbidity and mortality. To investigate a potential connection, we evaluated the association between salivary cortisol response to a high‐protein meal challenge and the metabolic syndrome (MetSyn), a subclinical disorder associated with increased cardiovascular risk.

Methods

Cross‐sectional data were from the Buffalo Cardio‐Metabolic Occupational Police Stress (BCOPS) Study (2004–2009). MetSyn was defined as having ≥3 components: abdominal obesity, hypertension, elevated triglycerides, reduced high‐density lipoprotein cholesterol, and glucose intolerance. Officers provided five saliva samples for cortisol analysis, one before challenge (high‐protein shake) and four at 15‐min intervals thereafter, where the usual response is increase. Regression models were used to examine trends in mean number of MetSyn components across quartiles of area under the curve (AUC) salivary cortisol. Patterns of mean cortisol response were assessed by MetSyn status using repeated‐measures analysis of covariance.

Results

Prevalence of MetSyn was 25.7% among 373 officers (74.0% male). The mean count of MetSyn components decreased (1.89, 1.75, 1.55, 1.37; P < 0.01) across increasing quartiles of AUC salivary cortisol. Mean salivary cortisol decreased from baseline (5.55, 4.58, 4.47, 4.79, 4.75 nmol/l) in officers with MetSyn and increased (5.08, 5.82, 5.92, 5.82, 5.60 nmol/l) in their counterparts. The test for interaction between MetSyn status and time of saliva collection was statistically significant (P < 0.001).

Conclusions

Reduced cortisol response to a high‐protein meal challenge may be associated with MetSyn. Future longitudinal studies could provide useful evidence for planning intervention studies on cardiovascular risk among police officers. Am. J. Hum. Biol. 28:138–144, 2016. © 2015 Wiley Periodicals, Inc.
Crossing the peninsula: The role of Noh Bec, Yucatán, in ancient Maya Classic Period population dynamics from an analysis of dental morphology and Sr isotopes
Authors: Cucina Andrea , Price T. Douglas , Magaña Peralta Evelia , Sierra Sosa Thelma
Published: June 2015

Objectives

This article aims to infer population dynamics in the Noh Bec region (Yucatán Peninsula, México) during the Maya Classic period (AD 350–800), based on a combined analysis of dental morphology and 87Sr/86Sr isotopes, and on a comparison of the dental evidence together with archaeological signs of trade and relationships with other regions in the Maya world.

Methods

Twenty‐three dental morphological variables were used to estimate affinities between dental collections from Noh Bec and 10 more sites from the region. 87Sr/86Sr isotopes were recorded from the enamel of permanent teeth of 32 individuals from Noh Bec, and compared to the site's local chemical signature.

Results

Dental morphology reveals a strong affinity with Kohunlich, in the central Maya lowlands, while some diversity can be noted with the Petén sites (such as Calakmul) as well as sites on the northern coast of the peninsula. The local extent of 87Sr/86Sr variation ranges between 0.7086 and 0.7088. Eight of the 32 Noh Bec individuals analyzed were born elsewhere. Isotopic values indicate different places of origin although apparently none were from the northern coast of the peninsula; instead, the range of variability reflects many locations along the western coast of the peninsula as well as inland sites in the Chenes region in Campeche.

Conclusions

Dental morphology and 87Sr/86Sr ratios indicate intense population dynamics in the peninsula during the Maya Classic period. Despite the different nature of the dental and isotopic indicators, results agree with archaeological evidence and with proposed trade routes in the peninsula. Am. J. Hum. Biol. 27:767–778, 2015. © 2015 Wiley Periodicals, Inc.
Maya paleodemographics: What do we know?
Authors: Olga Hernández Espinoza Patricia , Márquez Morfín Lourdes
Published: June 2015

Objectives

We present a review of what is known about the population dynamics from Classic and Post‐Classic Maya settlements in coastal areas of the Yucatan Peninsula such as Jaina, Chac Mool, El Meco and Xcambó and two other urban centers, Palenque and Copan.

Methods

This contribution discusses the available data on mortality, survival, life expectancy, fertility and migration, obtained by paleodemographic methodology. Data for Xcambó and El Meco were obtained from Tiesler Bloss et al., (2005) and Ortega (2007); information from other sites was obtained from previous work conducted by the authors.

Results

This review proposes that the demographic dynamics of the Classical period are typical of densely populated and developing areas with overall average birth rates of six children per woman and a life expectancy at birth of between 20 and 42.2 years, which is equivalent to birth rates above 40 per thousand inhabitants. Post‐Classic settlements show evidence of great population mobility with unfavorable changes in living conditions that lead us to think of fertility decrease and low life expectancies at birth.

Conclusions

There are indications of a demographic change between the Late‐Terminal Classic and Post‐Classic periods. Life expectancies are lower than 30 years, a high infant mortality and low adult survival after 50 years is shown. The Post‐Classic period is characterized by population rearrangements and mobility. Results obtained for both Chac Mool series showed deterioration in health and reduced life expectancy and fertility levels from one period to another. El Meco and Xcambó series showed differences with Chac Mool's due to higher growth rates. Am. J. Hum. Biol. 27:747–757, 2015. © 2015 Wiley Periodicals, Inc.
Socioeconomic status and sex ratios at birth in Sweden: No evidence for a Trivers–Willard effect for a wide range of status indicators
Authors: Kolk Martin , Schnettler Sebastian
Published: June 2015

Objectives

This study examines if there exists a positive association between socioeconomic status and the proportion of male births in humans, as proposed by Trivers and Willard in 1973, using individual‐level data drawn from the complete population of Sweden.

Methods

We examine more than 3,000,000 births between 1960 and 2007 using administrative register data with comprehensive information on various dimensions of socioeconomic status. We use six different operationalizations of socioeconomic status, including earnings, post‐transfer income (including government allowances), wealth, parental wealth, educational level, and occupational class. We apply regression models that compare both changes in status for the same woman over time and differences in status across different women. We also measure socioeconomic status both at the year of child birth and the year of conception.

Results

Our results show the absence of any relationship between socioeconomic status and sex ratios, using a large number of different operationalizations of status.

Conclusions

We conclude that no substantive relationship between socioeconomic status and sex ratios exists for the population and period of our study. Am. J. Hum. Biol. 28:67–73, 2016. © 2015 Wiley Periodicals, Inc.
Total body irradiation in a patient with fragile X syndrome for acute lymphoblastic leukemia in preparation for stem cell transplantation: A case report and literature review
Authors: Collins D. T. , Mannina E. M. , Mendonca M.
Published: June 2015

Fragile X syndrome (FXS) is a congenital disorder caused by expansion of CGG trinucleotide repeat at the 5' end of the fragile X mental retardation gene 1 (FMR1) on the X chromosome that leads to chromosomal instability and diminished serum levels of fragile X mental retardation protein (FMRP). Afflicted individuals often have elongated features, marfanoid habitus, macroorchidism and intellectual impairment. Evolving literature suggests the condition may actually protect from malignancy while chromosomal instability would presumably elevate the risk. Increased sensitivity to ionizing radiation should also be predicted by unstable sites within the DNA. Interestingly, in this report, we detail a patient with FXS diagnosed with acute lymphoblastic leukemia treated with induction followed by subsequent cycles of hyper‐CVAD (cyclophosphamide, vincristine, doxorubicin, dexamethasone) with a complete response who then was recommended to undergo peripheral stem cell transplantation. The patient underwent total body irradiation (TBI) as a component of his conditioning regimen and despite the concern of his clinicians, developed minimal acute toxicity and successful engraftment. The pertinent literature regarding irradiation of patients with FXS is also reviewed. © 2015 Wiley Periodicals, Inc.
Enantioselective Reduction of Ketones Induced by a C2‐Symmetrical Chiral Hydroxyamide/Titanium(IV) complex
Authors: Phothongkam Supannee , Uang Biing‐Jiun
Published: June 2015

The asymmetric reduction of ketones catalyzed by chiral titanium complex, prepared in situ from titanium tetraisopropoxide and a C2‐symmetrical chiral hydroxyamide, with catecholborane as the reducing agent afforded the corresponding chiral secondary alcohols in good yields with high enantioselectivity of up to>99 % ee.
The Dermatophagoides farinae group 22 allergen: cloning and expression in Escherichia coli
Authors: Cui Yu‐bao , Cai Hong‐xing , Zhou Ying , Wang Nan , Yu Li‐li , Yang Li , Zhang Cheng‐bo
Published: June 2015

Background

Dermatophagoides farinae (Hughes) (Acari: Pyroglyphidae) and other domestic mites produce allergens that affect people worldwide. Here, the complementary DNA (cDNA) coding for group 22 allergen of D. farinae (Der f 22) from China was cloned, sequenced, and expressed successfully.

Methods

The cDNA encoding Der f 22 was synthesized by reverse transcription polymerase chain reaction (RT‐PCR), then ligated to the pCold‐TF for expression in Escherichia coli BL21 cells. The purified recombinant fusion protein was identified by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS‐PAGE), Western‐blotting, and tandem matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF/TOF).

Results

The full‐length cDNA comprised 468 nucleotides and was 99.57% (466/468) identical with the reference sequence (GenBank: DQ643992). After the plasmid pCold‐TF‐Der f 22 was transformed into E. coli BL21 and expressed with the induction of IPTG, SDS‐PAGE showed a specific band for the recombinant fusion protein. The recombinant fusion protein, which was purified by chromatography, bound with a His‐tagged antibody by Western blotting. MALDI‐TOF/TOF mass spectrometry revealed that the structure of the recombinant protein was identical to the predicted Der f 22 structure. The hydrophilic protein contains a signal peptide of 20 amino acids, and the mature Der f 22 consists of 135 amino acid residues with a molecular weight of 14.7 kDa and theoretical isoelectric points (pI) of 6.38. Its secondary structure comprises an alpha helix (38.5%), beta‐sheet (45.9%), random coils (11.85%), and beta‐turns (11.1%).

Conclusion

This work represents the first reported full‐length sequence and successful cloning of Der f 22 from D. farinae in China; bioinformatics analysis can be used to further study the allergenicity and clinical utility of the recombinant Der f 22.
Clarithromycin in γ‐aminobutyric acid–Related hypersomnolence: A randomized, crossover trial
Authors: Trotti Lynn Marie , Saini Prabhjyot , Bliwise Donald L. , Freeman Amanda A. , Jenkins Andrew , Rye David B.
Published: June 2015

Objective

Some central hypersomnolence syndromes are associated with a positive allosteric modulator of γ‐aminobutyric acid (GABA)‐A receptors in cerebrospinal fluid. Negative allosteric modulators of GABA‐A receptors, including clarithromycin, have been reported to reduce sleepiness in these patients. We sought to systematically assess the effects of clarithromycin on objective vigilance and subjective sleepiness.

Methods

This was a 5‐week, randomized, placebo‐controlled, double‐blind, crossover trial of clarithromycin 500mg with breakfast and lunch, in patients with hypersomnolence syndromes (excluding narcolepsy with cataplexy) and evidence for abnormal cerebrospinal fluid potentiation of GABA‐A receptors. The study occurred at a university‐affiliated medical center. The primary outcome measure was median reaction time on the psychomotor vigilance task (PVT) at week 2 in each condition. Secondary outcomes included the Epworth Sleepiness Scale, Stanford Sleepiness Scale, Functional Outcomes of Sleep Questionnaire, Pittsburgh Sleep Quality Index, SF‐36, and additional PVT measures.

Results

Twenty‐three patients began treatment. Three patients dropped out, and final analyses were performed on 20 complete cases. Median reaction time was not significantly different between clarithromycin and placebo. Subjective measures of sleepiness were significantly improved on clarithromycin versus placebo. Altered taste perception occurred, but was the only side effect more common on clarithromycin than placebo. No serious adverse events occurred.

Interpretation

Subjective sleepiness, but not psychomotor vigilance, improved during a 2‐week course of clarithromycin. Although additional studies are needed, this suggests that clarithromycin may be a reasonable treatment option in patients with treatment‐refractory hypersomnolence. This trial was registered at ClinicalTrials.gov (NCT01146600) and supported by the American Sleep Medicine Foundation. Ann Neurol 2015 Ann Neurol 2015;78:454–465
Das Bindeglied zwischen Bisyliden und Methandiiden: Isolierung, Reaktivität und elektronische Struktur eines Yldiids
Authors: Scherpf Thorsten , Wirth Regina , Molitor Sebastian , Feichtner Kai‐Stephan , Gessner Viktoria H.
Published: June 2015

Bisylide und Methandiide stellen aufgrund ihrer elektronischen Struktur zwei besondere Klassen von Kohlenstoffbasen dar, die in den letzten Jahren eine Vielzahl an Anwendungen gefunden haben. Metallierte Ylide (Yldiide) sind das Bindeglied zwischen beiden Verbindungsklassen. Über ihre Eigenschaften, Reaktivitäten und besonders über ihre elektronische Struktur ist jedoch bis heute nur wenig bekannt. Hier berichten wir über die Synthese des metallierten Ylids [Ph3P‐C‐SO2Tol]− (1) mit verschiedenen Alkalimetall‐Gegenionen. Die Verbindungen wurden mit Einkristall‐Röntgenstrukturanalyse und NMR‐Spektroskopie untersucht und die erste Struktur eines Natrium‐ sowie eines Kalium‐Yldiids aufgeklärt. Die elektronische Struktur von 1 wurde mithilfe von DFT‐Rechnungen untersucht, die die Verwandtschaft mit anderen divalenten Kohlenstoffverbindungen aufzeigen. Reaktivitätsstudien belegen die starke Nukleophilie des Yldiids, aber insbesondere auch sein ungewöhnliches Donorvermögen (σ‐ und π‐Donor).
Oxidative Decarboxylierung von kurzkettigen Fettsäuren zu 1‐Alkenen
Authors: Dennig Alexander , Kuhn Miriam , Tassoti Sebastian , Thiessenhusen Anja , Gilch Stefan , Bülter Thomas , Haas Thomas , Hall Mélanie , Faber Kurt
Published: June 2015

Die enzymatische oxidative Decarboxylierung von linearen kurzkettigen Fettsäuren (C4:0–C9:0) unter Verwendung der P450‐Monooxygenase OleT, O2 und NAD(P)H als Elektronendonor ermöglicht die Synthese terminaler C3‐ bis C8‐Alkene mit Produkttitern von bis zu 0.93 g L−1 und TTNs >2000. Essentiell für diesen Prozess war die Entwicklung einer effizienten Elektronentransferkette unter Verwendung von Putidaredoxin (CamAB) und NAD(P)H‐Regeneration basierend auf Glukose, Ameisensäure oder Phosphonat. Mithilfe dieses Reaktionssystems lassen sich auf biokatalytischem Weg industriell wichtige Alkene, wie z. B. Propen und 1‐Octen zum ersten Mal vollständig aus nachwachsenden Rohstoffen herstellen.
Enantioselective Borylative Dearomatization of Indoles through Copper(I) Catalysis
Authors: Kubota Koji , Hayama Keiichi , Iwamoto Hiroaki , Ito Hajime
Published: June 2015

The enantioselective borylative dearomatization of a heteroaromatic compound has been achieved using a copper(I) catalyst and a diboron reagent. This reaction involves the regio‐ and enantioselective addition of active borylcopper(I) species to indole‐2‐carboxylates, followed by the diastereoselective protonation of the resulting copper(I) enolate to give the corresponding chiral indolines, which bear consecutive stereogenic centers.
Enzymatic Method for the Synthesis of Long DNA Sequences with Multiple Repeat Units
Authors: Whitfield Colette J. , Turley Andrew T. , Tuite Eimer M. , Connolly Bernard A. , Pike Andrew R.
Published: June 2015

A polymerase chain reaction (PCR) derived method for preparing long DNA, consisting of multiple repeat units of one to ten base pairs, is described. Two seeding oligodeoxynucleotides, so‐called oligoseeds, which encode the repeat unit and produce a duplex with 5′‐overhangs, are extended using a thermostable archaeal DNA polymerase. Multiple rounds of heat–cool extension cycles, akin to PCR, rapidly elongate the oligoseed. Twenty cycles produced long DNA with uniformly repeating sequences to over 20 kilobases (kb) in length. The polynucleotides prepared include [A]n/[T]n, [AG]n/[TC]n, [A2G]n/[T2C]n, [A3G]n/[T3C]n, [A4G]n/[T4C]n, [A9G]n/[T9C]n, [GATC]n/[CTAG]n, and [ACTGATCAGC]n/[TGACTAGTCG]n, indicating that the method is extremely flexible with regard to the repeat length and base sequence of the initial oligoseeds. DNA of this length (20 kb≈7 μm) with strictly defined base reiterations should find use in nanomaterial applications.
Water‐Promoted Generation of a Diazairida Homobarrelene by CC Coupling Between an Iridacyclic Alkylidene and Acetonitrile
Authors: Espada María F. , López‐Serrano Joaquín , Poveda Manuel L. , Carmona Ernesto
Published: June 2015

The stable cationic iridacyclopentenylidene [TpMe2Ir(CHC(Me)C(Me)CH2(NCMe)]PF6 (A; TpMe2=hydrotris(3,5‐dimethylpyrazolyl)borate) has been obtained by α‐hydride abstraction from the iridacyclopent‐2‐ene [TpMe2Ir(CH2C(Me)C(Me)CH2)(NCMe)]. Complex A exhibits Brønsted–Lowry acidity at the IrCH2 and proximal (relative to IrCH2) methyl sites. The coordination of an extra molecule of acetonitrile to the iridium center initiates the reversible isomerization of the chelating carbon chain of A to the monodentate butadienyl ligand of complex [TpMe2Ir(CHC(Me)C(Me)CH2)(NCMe)2]PF6, which is capable to engage in a water‐promoted CC coupling with the MeCN co‐ligands. The product is an aesthetically appealing bicyclic structure that resembles the hydrocarbon barrelene.
Integrating a Photocatalyst into a Hybrid Lithium–Sulfur Battery for Direct Storage of Solar Energy
Authors: Li Na , Wang Yarong , Tang Daiming , Zhou Haoshen
Published: June 2015

Direct capture and storage of abundant but intermittent solar energy in electrical energy‐storage devices such as rechargeable lithium batteries is of great importance, and could provide a promising solution to the challenges of energy shortage and environment pollution. Here we report a new prototype of a solar‐driven chargeable lithium–sulfur (Li‐S) battery, in which the capture and storage of solar energy was realized by oxidizing S2− ions to polysulfide ions in aqueous solution with a Pt‐modified CdS photocatalyst. The battery can deliver a specific capacity of 792 mAh g−1 during 2 h photocharging process with a discharge potential of around 2.53 V versus Li+/Li. A specific capacity of 199 mAh g−1, reaching the level of conventional lithium‐ion batteries, can be achieved within 10 min photocharging. Moreover, the charging process of the battery can proceed under natural sunlight irradiation.
Nickel‐Catalyzed Chemo‐, Regio‐ and Diastereoselective Bond Formation through Proximal CC Cleavage of Benzocyclobutenones
Authors: Juliá‐Hernández Francisco , Ziadi Asraa , Nishimura Akira , Martin Ruben
Published: June 2015

The first catalytic intermolecular proximal C1C2 cleavage of benzocyclobutenones (BCB) without prior carbonyl activation or employing noble metals has been developed. This protocol operates at room temperature and is characterized by an exquisite chemo‐, regio‐ and diastereoselectivity profile, constituting a unique platform for preparing an array of elusive carbocyclic skeletons.