bluuebunny/crossref_metadata_2025 huggingface dataset:
Internal Biasing in Relaxor Ferroelectric Polymer to Enhance the Electrocaloric Effect
Authors: Qian Xiaoshi , Ye Hui‐Jian , Yang Tiannan , Shao Wen‐Zhu , Zhen Liang , Furman Eugene , Chen Long‐Qing , Zhang Qiming
Published: July 2015

The relaxor ferroelectric materials, because of their large and reversible electric field induced polarization, have been demonstrated to possess giant electrocaloric effect (ECE) over a broad temperature range, which are attractive for refrigeration with high energy efficiency and environmental friendliness. However, high electric fields are required to generate the giant ECE in these materials, posing challenge for these materials in practical cooling devices which also require high reliability and low cost. Here, a general approach is reported, for example, establishing an internal bias field in these relaxor ferroelectric polymers, to significantly improve ECE which can be induced at low electric fields. It is demonstrated that in a polymer blend (nanocomposite) with a properly controlled normal ferroelectric in nanophase dispersion in the relaxor polymer matrix, the charge neutrality in the blends can cause an internal biasing field, leading to more than 45% enhancement in the ECE at low electric field (≈50 MV m−1). This internal biasing approach provides a universal strategy to enhance other low field responses such as the electromechanical response in relaxor ferroelectrics.
The Interplay of Modulus, Strength, and Ductility in Adhesive Design Using Biomimetic Polymer Chemistry
Authors: Meredith Heather J. , Wilker Jonathan J.
Published: July 2015

High‐performance adhesives require mechanical properties tuned to demands of the surroundings. A mismatch in stiffness between substrate and adhesive leads to stress concentrations and fracture when the bonding is subjected to mechanical load. Balancing material strength versus ductility, as well as considering the relationship between adhesive modulus and substrate modulus, creates stronger joints. However, a detailed understanding of how these properties interplay is lacking. Here, a biomimetic terpolymer is altered systematically to identify regions of optimal bonding. Mechanical properties of these terpolymers are tailored by controlling the amount of a methyl methacrylate stiff monomer versus a similar monomer containing flexible poly(ethylene glycol) chains. Dopamine methacrylamide, the cross‐linking monomer, is a catechol moiety analogous to 3,4‐dihydroxyphenylalanine, a key component in the adhesive proteins of marine mussels. Bulk adhesion of this family of terpolymers is tested on metal and plastic substrates. Incorporating higher amounts of poly(ethylene glycol) into the terpolymer introduces flexibility and ductility. By taking a systematic approach to polymer design, the region in which material strength and ductility are balanced in relation to the substrate modulus is found, thereby yielding the most robust joints.
Hierarchical Tubular Structures Composed of Mn‐Based Mixed Metal Oxide Nanoflakes with Enhanced Electrochemical Properties
Authors: Guo Yan , Yu Le , Wang Cheng‐Yang , Lin Zhan , Lou Xiong Wen (David)
Published: July 2015

In this work, a simple strategy is developed to synthesize hierarchical tubular structures (HTS) of Mn‐based (Co‐Mn, Ni‐Mn, Cu‐Mn, Zn‐Mn) mixed metal oxides. The first step in the synthesis involves redox reaction mediated growth of nanoflakes on carbon nanofibers under hydrothermal conditions. After calcination in air, carbon nanofibers are removed and HTS of mixed metal oxides can be obtained with little structural deterioration. The resultant HTS are advantageous as electrodes for electrochemical energy storage. As an example, it is shown that the Co‐Mn‐HTS sample exhibits outstanding electrochemical performance as electrode materials for hybrid supercapacitors and lithium ion batteries.
Recombinant Technology in the Development of Materials and Systems for Soft‐Tissue Repair
Authors: Girotti Alessandra , Orbanic Doriana , Ibáñez‐Fonseca Arturo , Gonzalez‐Obeso Constancio , Rodríguez‐Cabello José Carlos
Published: July 2015

The field of biomedicine is constantly investing significant research efforts in order to gain a more in‐depth understanding of the mechanisms that govern the function of body compartments and to develop creative solutions for the repair and regeneration of damaged tissues. The main overall goal is to develop relatively simple systems that are able to mimic naturally occurring constructs and can therefore be used in regenerative medicine. Recombinant technology, which is widely used to obtain new tailored synthetic genes that express polymeric protein‐based structures, now offers a broad range of advantages for that purpose by permitting the tuning of biological and mechanical properties depending on the intended application while simultaneously ensuring adequate biocompatibility and biodegradability of the scaffold formed by the polymers. This Progress Report is focused on recombinant protein‐based materials that resemble naturally occurring proteins of interest for use in soft tissue repair. An overview of recombinant biomaterials derived from elastin, silk, collagen and resilin is given, along with a description of their characteristics and suggested applications. Current endeavors in this field are continuously providing more‐improved materials in comparison with conventional ones. As such, a great effort is being made to put these materials through clinical trials in order to favor their future use.
Well‐Defined Metal–Organic‐Framework Hollow Nanostructures for Catalytic Reactions Involving Gases
Authors: Xu Xiaobin , Zhang Zhicheng , Wang Xun
Published: July 2015

The miniaturization of metal–organic‐framework (MOF) crystals to the nanoscale brings enhanced or novel properties and fulfils specific application needs. The focus here is on a kind of nanoMOF with special configurations and outstanding properties – the hollow structure. Firstly recent advances on the synthesis of MOF hollow nanostructures are introduced. Then, a novel approach based on a heterometallic system is highlighted, by which the facile synthesis of well‐defined hollow MOF structures with high complexity is achieved. Moreover, MOF hollow nanostructures are emphasized as hosts/shell materials to incorporate functional catalysts that show dramatically enhanced performances in gas‐involved reactions due to their inherent gas‐absorption/storage properties.
Engineering of Carbon‐Based Electrocatalysts for Emerging Energy Conversion: From Fundamentality to Functionality
Authors: Zheng Yao , Jiao Yan , Qiao Shi Zhang
Published: July 2015

Over the past decade, developing advanced catalysts for clean and sustainable energy conversion has been subject to extensive study. Driven by great advances achieved in computational quantum chemistry, synthetic chemistry, and material characterization techniques, the preferential design of a most‐appropriate catalyst for a specific electrochemical reaction is possible. Here a universal process for the design of high‐performance carbon‐based electrocatalysts, by engineering their intrinsic electronic structures and physical structures to promote their extrinsic activities for different energy conversion reactions, is presented and summarized. How such a powerful strategy may aid the discovery of more electrocatalysts for a sustainable and clean energy infrastructure is discussed.
Porphyrin Supramolecular 1D Structures via Surfactant‐Assisted Self‐Assembly
Authors: Zhang Congcong , Chen Penglei , Dong Huanli , Zhen Yonggang , Liu Minghua , Hu Wenping
Published: July 2015

One‐dimensional (1D) solid‐state supramolecular structures based on porphyrin chromophores arouse numerous expectations from the interdisciplinary scientific communities of supramolecular chemistry and advanced soft materials science. This stems from the intrinsic assembly capability of porphyrins to form various well‐defined 1D assemblies, which have broad opportunities in the fields of advanced soft matter. A brief review on 1D porphyrin micro‐/nanoassemblies constructed via surfactant‐assisted self‐assembly is presented here, in terms of addressing new ideas recently developed for controlled assembly, hierarchical organization, and new‐type functional surfactants etc. The functionalization of the as‐assembled 1D structures with regard to supramolecular photocatalysis, non‐linear optics, nanoelectronic gas sensors, photoelectrochemical solar cells, etc. is highlighted.
Chemical Control of Plasmons in Metal Chalcogenide and Metal Oxide Nanostructures
Authors: Mattox Tracy M. , Ye Xingchen , Manthiram Karthish , Schuck P. James , Alivisatos A. Paul , Urban Jeffrey J.
Published: July 2015

The field of plasmonics has grown to impact a diverse set of scientific disciplines ranging from quantum optics and photovoltaics to metamaterials and medicine. Plasmonics research has traditionally focused on noble metals; however, any material with a sufficiently high carrier density can support surface plasmon modes. Recently, researchers have made great gains in the synthetic (both intrinsic and extrinsic) control over the morphology and doping of nanoscale oxides, pnictides, sulfides, and selenides. These synthetic advances have, collectively, blossomed into a new, emerging class of plasmonic metal chalcogenides that complement traditional metallic materials. Chalcogenide and oxide nanostructures expand plasmonic properties into new spectral domains and also provide a rich suite of chemical controls available to manipulate plasmons, such as particle doping, shape, and composition. New opportunities in plasmonic chalcogenide nanomaterials are highlighted in this article, showing how they may be used to fundamentally tune the interaction and localization of electromagnetic fields on semiconductor surfaces in a way that enables new horizons in basic research and energy‐relevant applications.
Construction of FeS2‐Sensitized ZnO@ZnS Nanorod Arrays with Enhanced Optical and Photoresponse Performances
Authors: Wang Mudan , Chen Chenxu , Qin Haiying , Zhang Lei , Fang Youtong , Liu Jiabin , Meng Liang
Published: July 2015

FeS2‐sensitized ZnO@ZnS nanorod arrays are fabricated by a two‐step solution immersion and a subsequent sulfurization. The material properties including structure, morphology, and photoluminescence are investigated by a variety of characterization methods. As compared with ZnO@ZnS core/shell structure, FeS2‐sensitized ZnO@ZnS nanorod arrays show improved optical absorption property with the extension of the absorption edge into the range of visible light. The photoresponse performance of FeS2‐sensitized Zno@ZnS is also enhanced as the photocurrent density at 1.0 V is dozens of times larger than that of ZnO@ZnS nanorods. The cause for the difference in such material properties of these two materials is discussed. In this work, a new method for sensitizing wide bandgap ZnO@ZnS nanorod arrays with improved light response performance is presented.
Silver Iodide Formation in Methyl Ammonium Lead Iodide Perovskite Solar Cells with Silver Top Electrodes
Authors: Kato Yuichi , Ono Luis K. , Lee Michael V. , Wang Shenghao , Raga Sonia R. , Qi Yabing
Published: July 2015

Silver is a low‐cost candidate electrode material for perovskite solar cells. However, in such cells the silver electrodes turn yellow within days of device fabrication. The color change is also accompanied by a dramatic decrease in the power conversion efficiency when compared to otherwise identical devices using gold electrodes. Here, it is shown that the color change results from silver oxidation to silver iodide, due to a reaction with iodine in methyl ammonium lead perovskite. The change in X‐ray diffraction and X‐ray photo­electron spectroscopy is discussed. Exposure to air accelerates corrosion of the Ag electrodes when compared to dry nitrogen gas exposure. However, iodine not reacted with silver is observed by X‐ray photoelectron spectroscopy even for the perovskite solar cell kept in dry nitrogen gas. It is proposed that silver iodide is formed when methyl ammonium iodide migration is facilitated by the small pinholes in the hole transport layer spiro‐MeOTAD.
Multifunctional Polymer/Porous Boron Nitride Nanosheet Membranes for Superior Trapping Emulsified Oils and Organic Molecules
Authors: Liu Dan , He Li , Lei Weiwei , Klika Karel D. , Kong Lingxue , Chen Ying
Published: July 2015

Effective oil/water separation and removal of organic molecules from water are of worldwide importance for water source protection. Multifunctional sorbent materials with excellent sorption capacity, stability, and recyclability properties need to be developed. Here, flexible and multifunctional polymer/porous boron nitride nanosheets (BNNSs) membranes with high water permeability, exhibiting high effectiveness and stability in the purification of simulated wastewater tainted with either oil/water emulsion or organic molecules, are reported. Remarkably, the flexible nature of these porous membranes enables simplicity of operation for water remediation processing and ease of post‐processing collection. The composite membrane also displays a remarkably high permeability of 8 × 104 L μm m−2 h−1 bar−1, roughly three orders of magnitude higher than pure polymer, and excellent filter efficiencies for the pharmaceuticals ciprofloxacin, chlortetracycline, and carbamazepine (up to 14.2 L g−1 of BNNSs in the composite membrane for a concentration of 10 mg L−1 ciprofloxacin) and the dye methylene blue (up to 9.3 L g−1 of BNNSs in the composite membrane at a concentration of 30 mg L−1). Exhausted membranes can be readily rejuvenated by simple washing with retention of their high‐performance characteristics. The results demonstrate the potential efficacy and practicality of these membranes for water cleaning.
Light Amplification in an Organic Solid‐State Film with the Aid of Triplet‐to‐Singlet Upconversion
Authors: Nakanotani Hajime , Furukawa Taro , Adachi Chihaya
Published: July 2015

Organic laser dyes can be optically excited to achieve light amplification. The buildup of an excessive population of triplets is generally believed to limit the duration of the light amplification because of optical losses through excited‐state absorption, so triplet excitons are usually eliminated by using a triplet quencher. However, destroying the triplets limits the electroluminescence efficiency of organic materials under electrical pumping and is counterproductive to realizing electrically pumped organic laser devices. Herein, light amplification is reported which constructively uses triplet states in an optically pumped organic film. In this system, the triplets are converted into singlets by reverse intersystem crossing in a “triplet harvester,” and then the singlets are resonantly transferred to the singlet state of the laser dye. Since this approach permits the constructive use of triplets, not only gain‐narrowed emission but also enhanced electroluminescence efficiency was observed, indicating that the threshold current density for lasing might be reduced.
Graphene‐Containing Nanomaterials for Lithium‐Ion Batteries
Authors: Wu Songping , Xu Rui , Lu Mingjia , Ge Rongyun , Iocozzia James , Han Cuiping , Jiang Beibei , Lin Zhiqun
Published: July 2015

Graphene‐containing nanomaterials have emerged as important candidates for electrode materials in lithium‐ion batteries (LIBs) due to their unique physical properties. In this review, a brief introduction to recent developments in graphene‐containing nanocomposite electrodes and their derivatives is provided. Subsequently, synthetic routes to nanoparticle/graphene composites and their electrochemical performance in LIBs are highlighted, and the current state‐of‐the‐art and most recent advances in the area of graphene‐containing nanocomposite electrode materials are summarized. The limitations of graphene‐containing materials for energy storage applications are also discussed, with an emphasis on anode and cathode materials. Potential research directions for the future development of graphene‐containing nanocomposites are also presented, with an emphasis placed on practicality and scale‐up considerations for taking such materials from benchtop curiosities to commercial products.
Cation Substitution of Solution‐Processed Cu2ZnSnS4 Thin Film Solar Cell with over 9% Efficiency
Authors: Su Zhenghua , Tan Joel Ming Rui , Li Xianglin , Zeng Xin , Batabyal Sudip Kumar , Wong Lydia Helena
Published: July 2015

To alleviate the limitations of pure sulfide Cu2ZnSnS4 (CZTS) thin film, such as band gaps adjustment, antisite defects, secondary phase and microstructure, Cadmium is introduced into CZTS thin film to replace Zn partially to form Cu2Zn1−xCdxSnS4 (CZCTS) thin film by low‐cost sol–gel method. It is demonstrated that the band gaps and crystal structure of CZCTS thin films are affected by the change in Zn/Cd ratio. In addition, the ZnS secondary phase can be decreased and the grain sizes can be improved to some degree by partial replacement of Zn with Cd in CZCTS thin film. The power conversion efficiency of CZTS solar cell device is enhanced significantly from 5.30% to 9.24% (active area efficiency 9.82%) with appropriate ratio of Zn/Cd. The variation of device parameter as a function of Zn/Cd ratio may be attributed to the change in electronic structure of the bulk CZCTS thin film (i.e., phase change from kesterite to stannite), which in turn affects the band alignment at the CZCTS/buffer interface and the charge separation at this interface.
Similar or Totally Different: the Adjustment of the Twist Conformation Through Minor Structural Modification, and Dramatically Improved Performance for Dye‐Sensitized Solar Cell
Authors: Chai Zhaofei , Wu Mei , Fang Manman , Wan Sushu , Xu Ting , Tang Runli , Xie Yujun , Mei Anyi , Han Hongwei , Li Qianqian , Li Zhen
Published: July 2015

A novel approach for enhancing the performance of dye‐sensitized solar cells is presented. It is based on the analysis of five sensitizers by utilizing triarylamine as donor, thiophene benzothiadiazole as chromophore and substituted thienyl linked with cyanoacrylic acid as the anchoring group (LI‐80‐LI‐84). Accompanied with the increasing steric hindrance of the substituents on the thienyl isolation group, the conformation of the dyes, in particular the angle between the chromophore and the anchoring group, becomes more and more twisted. Surprisingly, sensitizers with poorer conjugation effects (the higher twisted conformation) achieve better photovoltaic performances, showing a contrary trend to the traditional donor‐(π‐spacer)‐acceptor dyes with a better co‐planarity. On the basis of the preceding fundamental comprehensions, an empirical method is successfully applied to a new phenyl‐based system (LI‐85 and LI‐86) to improve their performances. The systematical investigation indicates that the twisted structures can contribute to the ECB of the TiO2 film, electron lifetime and resistance at the TiO2/dye/electrolyte interface. Thereby, the efficiency of the initial LI‐80‐based cell has been dramatically improved to 2.45 times higher for LI‐86‐based cell, paving a new way for the design of better sensitizers with higher device performances.
Synergistic Impact of Solvent and Polymer Additives on the Film Formation of Small Molecule Blend Films for Bulk Heterojunction Solar Cells
Authors: McDowell Caitlin , Abdelsamie Maged , Zhao Kui , Smilgies Detlef‐M. , Bazan Guillermo C. , Amassian Aram
Published: July 2015

The addition of polystyrene (PS), a typical insulator, is empirically shown to increase the power conversion efficiencies (PCEs) of a solution‐deposited bulk heterojunction (BHJ) molecular blend film used in solar cell fabrication: p‐DTS(FBTTh2)2/PC71BM. The performance is further improved by small quantities of diiodooctane (DIO), an established solvent additive. In this study, how the addition of PS and DIO affects the film formation of this bulk heterojunction blend film are probed via in situ monitoring of absorbance, thickness, and crystallinity. PS and DIO additives are shown to promote donor crystallite formation on different time scales and through different mechanisms. PS‐containing films retain chlorobenzene solvent, extending evaporation time and promoting phase separation earlier in the casting process. This extended time is insufficient to attain the morphology for optimal PCE results before the film sets. Here is where the presence of DIO comes into play: its low vapor pressure further extends the time scale of film evolution and allows for crystalline rearrangement of the donor phase long after casting, ultimately leading to the best BHJ organization.
Microstructure of room temperature ionic liquids at stepped graphite electrodes
Authors: Feng Guang , Li Song , Zhao Wei , Cummings Peter T.
Published: July 2015

Molecular dynamics simulations of room temperature ionic liquid (RTIL) [emim][TFSI] at stepped graphite electrodes were performed to investigate the influence of the thickness of the electrode surface step on the microstructure of interfacial RTILs. A strong correlation was observed between the interfacial RTIL structure and the step thickness in electrode surface as well as the ion size. Specifically, when the step thickness is commensurate with ion size, the interfacial layering of cation/anion is more evident; whereas, the layering tends to be less defined when the step thickness is close to the half of ion size. Furthermore, two‐dimensional microstructure of ion layers exhibits different patterns and alignments of counterion/co‐ion lattice at neutral and charged electrodes. As the cation/anion layering could impose considerable effects on ion diffusion, the detailed information of interfacial RTILs at stepped graphite presented here would help to understand the molecular mechanism of RTIL‐electrode interfaces in supercapacitors. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3022–3028, 2015
Determination and comparison of rotational velocity in a pseudo 2‐D fluidized bed using magnetic particle tracking and discrete particle modeling
Authors: Buist K. A. , van Erdewijk T. W. , Deen N. G. , Kuipers J. A. M.
Published: July 2015

Modeling of dense granular flow has been subject to a large amount of research. Particularly discrete particle modeling has been of great importance because of the ability to describe the strongly coupled dynamics of the fluid and the solids in dense suspensions. Many studies have been reported on the validation of the translational particle velocities predicted by using these models. The rotational motion however has received far less attention, mainly because of the spherical nature of the particles under investigation and the lack of techniques with the capability to study the rotational behavior of the solid phase. In this study, we will for the first time present experimental data on the rotational behavior of particles in a pseudo two‐dimensional fluidized bed setup using Magnetic Particle Tracking. In addition the experimental results are compared to data obtained from discrete particle simulations. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3198–3207, 2015
Congenital limb deficiencies in Alberta—a review of 33 years (1980–2012) from the Alberta Congenital Anomalies Surveillance System (ACASS)
Authors: Bedard Tanya , Lowry Robert Brian , Sibbald Barbara , Kiefer Gerhard N. , Metcalfe Amy
Published: July 2015

The birth prevalence of limb deficiencies in Alberta has been fluctuating. The objectives were to examine patterns and temporal trends of congenital limb deficiencies in Alberta and compare rates with those of other jurisdictions. The Alberta Congenital Anomalies Surveillance System data on live births, stillbirths, and terminations of pregnancy (<20 weeks gestation) occurring between 1980 through 2012 with the ICD‐10 Royal College of Paediatrics and Child Health Adaptations codes Q71‐Q73 (limb reduction defects), Q79.80 (congenital constriction bands), and Q87.24 (sirenomelia syndrome) were reviewed. Cases were classified as having amelia, transverse, longitudinal (preaxial, postaxial, central, or mixed), intercalary, split hand/split foot, complex, or other type of limb deficiency. Phenotypes were classified as associated, which included cases with a known etiology and cases with at least one other type of anomaly, or isolated. From 1980 through 2012, 795 cases were ascertained from 1,411,652 live births and stillbirths, giving a prevalence of 5.6/10,000 total births. Mixed longitudinal deficiencies were the most common (22.4%). The upper limbs (63.9%) were affected more often than the lower limbs (25.3%). Isolated limb deficiencies occurred in 43.6% of cases, 28.4% had Mendelian or other known conditions, 21.9% had multiple congenital anomalies, 5.4% had chromosome abnormalities and 0.6% were due to teratogens. The associated group, showed a significant increasing trend (P =  0.023). While the overall limb deficiency rates show very little differences across diverse populations and differing time periods, comparisons of subgroups should be made with caution, because variations in terminology and classification contribute to reported differences. © 2015 Wiley Periodicals, Inc.
Jaw‐muscle force and excursion scale with negative allometry in platyrrhine primates
Authors: Taylor Andrea B. , Yuan Tian , Ross Callum F. , Vinyard Christopher J.
Published: July 2015

Objectives

Platyrrhines span two orders of magnitude in body size and are characterized by diverse feeding behaviors and diets. While size plays an important role in primate feeding behavior and masticatory apparatus morphology, we know little about size‐correlated changes in the force‐generating (physiologic cross‐sectional area; PCSA) and excursion/stretch (fiber length; Lf) capabilities of the jaw‐closing muscles in platyrrhines.

Methods

We examined scaling relationships of the superficial masseter and temporalis muscles in 21 platyrrhine species. Previous work suggests that larger platyrrhines are at a mechanical disadvantage for generating bite forces compared with smaller platyrrhines. We hypothesize that scaling of jaw‐muscle fiber architecture counters this size‐correlated decrease in mechanical advantage. Thus, we predicted that jaw‐muscle PCSAs and muscle weights scale with positive allometry while Lfs scale with negative allometry, relative to load‐arm estimates for incisor/molar biting and chewing.

Results

Jaw‐muscle PCSAs and Lfs appear to scale with negative allometry relative to load‐arm estimates and body size. Negative allometry of jaw‐muscle weights partially accounts for the size‐correlated decreases in PCSA and Lf. Estimates of bite force also scale with negative allometry.

Conclusion

Large‐bodied platyrrhines (e.g., Alouatta) are at a relative disadvantage for generating jaw‐muscle and bite force as well as jaw‐muscle stretch, compared with smaller species (e.g., Callithrix). The net effect is that larger platyrrhines likely produce relatively smaller maximal bite forces compared with smaller taxa. Relative to small‐ and intermediate‐sized platyrrhines, large‐bodied platyrrhines feed on some of the least mechanically challenging foods, consistent with the size‐correlated decrease in relative muscle and bite forces across the clade. Am J Phys Anthropol, 2015. © 2015 Wiley Periodicals, Inc. Am J Phys Anthropol 158:242–256, 2015. © 2015 Wiley Periodicals, Inc.
New dental and isotope evidence of biological distance and place of origin for mass burial groups atCahokia's mound 72
Authors: Thompson Andrew R. , Hedman Kristin M. , Slater Philip A.
Published: July 2015

Objectives:

Mound 72 at Cahokia figures prominently into interpretations of early Mississippian sociopolitical development. A previous study utilizing dental morphology concluded that the groups of mostly young adult females interred in four mass graves in Mound 72 were likely not from Cahokia and possibly reflect sacrificial offerings from outside communities. The purpose of this study is to reevaluate these findings using multiple indicators of biological relatedness and place of origin/migration.

Materials and Methods:

Biological relatedness in Mound 72 was examined using dental metrics and morphology. Four additional archaeological samples from nearby sites were included to better assess biological variation within Mound 72. Strontium isotope analysis (87Sr/86Sr) was also conducted on individuals from several burial features in Mound 72 to determine heterogeneity in place of origin.

Results:

Biodistance studies indicate that individuals in the four mass graves are phenotypically similar to other groups in the region, whereas F229‐lower, a burial group with an aberrant mortuary context, is phenotypically distinct. Strontium isotope analyses show that mean Sr signatures for each feature investigated fall within the established local range for Cahokia. However, the range of Sr ratios for individuals in F229‐lower is very narrow, suggesting they reflect a single population from a limited geologic region.

Discussion:

Collectively, these results question the long‐standing idea that individuals in the four mass graves were non‐local to Cahokia and suggest that F229‐lower contained a biologically dissimilar group that either came from an outside region with a similar Sr signature to Cahokia, or represent a distinct and restricted group from the region. Am J Phys Anthropol 158:341–357, 2015. © 2015 Wiley Periodicals, Inc.
An enhanced computational method for age‐at‐death estimation based on the pubic symphysis using 3D laser scans and thin plate splines
Authors: Stoyanova Detelina , Algee‐Hewitt Bridget F.B. , Slice Dennis E.
Published: July 2015

Objectives:

The pubic symphysis is frequently used to estimate age‐at‐death from the adult skeleton. Assessment methods require the visual comparison of the bone morphology against age‐informative characteristics that represent a series of phases. Age‐at‐death is then estimated from the age‐range previously associated with the chosen phase. While easily executed, the "morphoscopic" process of feature‐scoring and bone‐to‐phase‐matching is known to be subjective. Studies of method and practitioner error demonstrate a need for alternative tools to quantify age‐progressive change in the pubic symphysis. This article proposes a more objective, quantitative method that analyzes three‐dimensional (3D) surface scans of the pubic symphysis using a thin plate spline algorithm (TPS).

Materials and Methods:

This algorithm models the bending of a flat plane to approximately match the surface of the bone and minimizes the bending energy required for this transformation. Known age‐at‐death and bending energy were used to construct a linear model to predict age from observed bending energy. This approach is tested with scans from 44 documented white male skeletons and 12 casts.

Results:

The results of the surface analysis show a significant association (regression p‐value = 0.0002 and coefficient of determination = 0.2270) between the minimum bending energy and age‐at‐death, with a root mean square error of ≈19 years.

Discussion:

This TPS method yields estimates comparable to established methods but offers a fully integrated, objective and quantitative framework of analysis and has potential for use in archaeological and forensic casework. Am J Phys Anthropol 158:431–440, 2015. © 2015 Wiley Periodicals, Inc.
Association of protein intakes and variation of diet‐scalp hair nitrogen isotopic discrimination factor in Papua New Guinea highlanders
Authors: Naito Yuichi I. , Morita Ayako , Natsuhara Kazumi , Tadokoro Kiyoshi , Baba Jun , Odani Shingo , Tomitsuka Eriko , Igai Katsura , Tsutaya Takumi , Yoneda Minoru , Greenhill Andrew R. , Horwood Paul F. , Soli Kevin W. , Phuanukoonnon Suparat , Siba Peter M. , Umezaki Masahiro
Published: July 2015

Objectives:

We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ15NHair‐Diet: δ15NHair – δ15NDiet) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ15N is important for precise evaluation of the dietary habits of human populations; in both contemporary and traditional lifestyles. Several hypotheses have been proposed regarding factors that affect Δ15N values, based largely on observations from animal feeding experiments. However, variations and factors controlling Δ15N in humans are not well understood, mainly due to the difficulty of controlling the diets of participants.

Materials and Methods:

These residents were studied because they have maintained relatively traditional dietary habits, which allow quantitative recording of diets. Δ15N was estimated by comparing hair δ15N values to mean dietary δ15N values calculated from the recorded intake of each food item and their δ15N values.

Results:

The results showed that: i) there was a significant difference in Δ15N among study locations (3.9 ± 0.9‰ for most urbanized, 5.2 ± 1.0‰ for medium and 5.0 ± 0.9‰ for least urbanized communities; range = 1.2–7.3‰ for all participants); and ii) estimated Δ15N values were negatively correlated with several indicators of animal protein intake (% nitrogen in diet: range = 0.9–7.6%).

Discussion:

We hypothesize that a combination of several factors, which presumably included urea recycling and amino acid and protein recycling and/or de novo synthesis during metabolic processes, altered the Δ15N values of the participants. Am J Phys Anthropol 158:359–370, 2015. © 2015 Wiley Periodicals, Inc.
Ancient remains and the first peopling of the Americas: Reassessing the Hoyo Negro skull
Authors: de Azevedo Soledad , Bortolini Maria C. , Bonatto Sandro L. , Hünemeier Tábita , Santos Fabrício R. , González‐José Rolando
Published: July 2015

Objective

A noticeably well‐preserved ∼12.500 years‐old skeleton from the Hoyo Negro cave, Yucatán, México, was recently reported, along with its archaeological, genetic and skeletal characteristics. Based exclusively on an anatomical description of the skull (HN5/48), Chatters and colleagues stated that this specimen can be assigned to a set of ancient remains that differ from modern Native Americans, the so called “Paleoamericans”. Here, we aim to further explore the morphological affinities of this specimen with a set of comparative cranial samples covering ancient and modern periods from Asia and the Americas.

Methods

Images published in the original article were analyzed using geometric morphometrics methods. Shape variables were used to perform Principal Component and Discriminant analysis against the reference samples.

Results

Even thought the Principal Component Analysis suggests that the Hoyo Negro skull falls in a subregion of the morphospace occupied by both “Paleoamericans” and some modern Native Americans, the Discriminant analyses suggest greater affinity with a modern Native American sample.

Discussion

These results reinforce the idea that the original population that first occupied the New World carried high levels of within‐group variation, which we have suggested previously on a synthetic model for the settlement of the Americas. Our results also highlight the importance of developing formal classificatory test before deriving settlement hypothesis purely based on macroscopic descriptions. Am J Phys Anthropol 158:514–521, 2015. © 2015 Wiley Periodicals, Inc.
Single‐limb force data for two lemur species while vertically clinging
Authors: Johnson Laura E. , Hanna Jandy , Schmitt Daniel
Published: July 2015

Objectives

Vertical clinging and climbing have been integral to hypotheses about primate origins, yet little is known about how an animal with nails instead of claws resists gravity while on large, vertical, and cylindrical substrates. Here we test models of how force is applied to maintain posture, predicting (1) the shear component force (Fs) at the hands will be higher than the feet; (2) the normal component force (Fn) at the feet will be relatively high compared to the hands; (3) the component force resisting gravity (Fg) at the feet will be relatively high compared to the hands; (4) species with a high frequency of vertical clinging postures will have low Fg at the hands due to relatively short forelimbs.

Materials and Methods

Using a novel instrumented support, single‐limb force data were collected during clinging postures for the hands and feet and compared across limbs and species for Propithecus verreauxi (N = 2), a habitual vertical clinger and leaper, and Varecia variegata (N = 3), a habitual above‐branch arboreal quadruped.

Results

For both species, hand Fs were significantly higher than at the feet and Fn and Fg at the feet were significantly higher than at the hands. Between species, P. verreauxi has relatively low Fg at the hands and Fn at the feet than V. vareigata.

Discussion

These results support previous models and show that hindlimb loading dominance, characteristic of primate locomotion, is found during clinging behaviors and may allow the forelimbs to be used for foraging while clinging. These findings provide insight into selective pressures on force distribution in primates and primate locomotor evolution. Am J Phys Anthropol 158:463–474, 2015. © 2015 Wiley Periodicals, Inc.
Assessing digestibility of Hadza tubers using a dynamic in‐vitro model
Authors: Schnorr Stephanie L. , Crittenden Alyssa N. , Venema Koen , Marlowe Frank W. , Henry Amanda G.
Published: July 2015

Objectives

Bioaccessibility is a useful measure for assessing the biological value of a particular nutrient from food, especially foods such as tubers. The wild tubers exploited by Hadza foragers in Tanzania are of interest because they are nontoxic, consumed raw or briefly roasted, and entail substantial physical barriers to consumers. In this study, we attempted to elucidate the biological value of Hadza tubers by measuring the absorption of glucose through in‐vitro digestion.

Methods

We quantified digestibility using data from 24 experimental trials on four species of Hadza tuber using a dynamic in‐vitro model that replicates digestion in the stomach and small intestine. Analysis of glucose in the input meal and output dialysate revealed the accessible glucose fraction. We also conducted assays for protein, vitamin, and mineral content on whole tubers and meal fractions.

Results

Bioaccessibility of glucose varies depending on tuber species. Holding effects of chewing constant, brief roasting had negligible effects, but high intraspecific variation precludes interpretive power. Overall, Hadza tubers are very resistant to digestion, with between one‐ and two‐thirds of glucose absorbed on average. Glucose absorption negatively correlated with glucose concentration of the tubers.

Conclusions

Roasting may provide other benefits such as ease of peeling and chewing to extract edible parenchymatous tissue. A powerful factor in glucose acquisition is tuber quality, placing emphasis on the skill of the forager. Other nutrient assays yielded unexpectedly high values for protein, iron, and iodine, making tubers potentially valuable resources beyond caloric content. Am J Phys Anthropol 158:371–385, 2015. © 2015 Wiley Periodicals, Inc.
Integration between the face and the mandible of Pongo and the evolution of the craniofacial morphology of orangutans
Authors: Neaux Dimitri , Gilissen Emmanuel , Coudyzer Walter , Guy Franck
Published: July 2015

Objectives

Extant Pongo diverges from other hominids by a series of craniofacial morphological features, such as a concave face, a reduced supraorbital torus, or an upwardly orientated palate. These traits are not independent because the skull is a complex integrated structure. The aim of this study is to describe the relationship between the face and mandible of Pongo, in order to examine the link between mandibular structures and the set‐up of the unique facial features of orangutans.

Materials and methods

Using 3D geometric morphometrics, the morphological integration between face and mandible of Pongo is compared to that of the three extant hominids: Homo, Pan, and Gorilla. Pooled within‐species partial least squares analyses are computed in order to quantify the patterns and levels of integration.

Results

The covariation analyses show unique patterns of integration and levels of correlation in Pongo when compared to other hominids. This study shows that the craniofacial features distinguishing Pongo from African great apes are related to differences in the patterns of integration and levels of correlation between facial and mandibular shape.

Discussion

Changes in important functions may play a part in these modifications of craniofacial integration. This study underlines the importance of the mandible and of the mandibular functions in the development of the unique craniofacial features of Pongo. Am J Phys Anthropol 158:475–486, 2015. © 2015 Wiley Periodicals, Inc.
The long‐term impact of developmental stress. Evidence from later medieval and post‐medieval London (AD1117–1853)
Authors: Watts Rebecca
Published: July 2015

Objectives

Episodes of ill‐health in childhood can predispose affected individuals to further periods of illness and early adult mortality. This study uses nonspecific indicators of stress to examine how growth disruptions during infancy/early childhood, and late childhood/early adolescence affected adult longevity in later medieval and post‐medieval London.

Materials and Methods

Hazards analysis was used to evaluate the effect of linear enamel hypoplasia (LEH) and the size of the anteroposterior (AP) and transverse (TR) diameters of the vertebral neural canal (VNC) on adult age‐at‐death. This was applied to skeletal samples from later medieval (n = 461) and post‐medieval (n = 480) London.

Results

Growth disruptions during infancy/early childhood (LEH and AP VNC diameters) were not associated with longevity, or with impaired growth at later stages of development (TR VNC diameters). Growth disruptions during late childhood/early adolescence (TR VNC diameters) were associated with a significantly increased risk of adult mortality.

Discussion

Macroscopic hypoplasia represent short periods of stress during infancy/early childhood which did not disrupt future investments in growth or cause long‐term damage to health. Small TR diameters represent chronic stress during late childhood/early adolescence which resulted in greater susceptibility to infections and increased risk of mortality. These interactions were influenced by sex and socioeconomic status, suggesting that socioeconomic circumstances in both childhood and adult life could influence exposure and resistance to stressors. Am J Phys Anthropol 158:569–580, 2015. © 2015 Wiley Periodicals, Inc.
Porous Zirconium–Phytic Acid Hybrid: a Highly Efficient Catalyst for Meerwein–Ponndorf–Verley Reductions
Authors: Song Jinliang , Zhou Baowen , Zhou Huacong , Wu Lingqiao , Meng Qinglei , Liu Zhimin , Han Buxing
Published: July 2015

The utilization of compounds from natural sources to prepare functional materials is of great importance. Herein, we describe for the first time the preparation of organic–inorganic hybrid catalysts by using natural phytic acid as building block. Zirconium phosphonate (Zr‐PhyA) was synthesized by reaction of phytic acid and ZrCl4 and was obtained as a mesoporous material with pore sizes centered around 8.5 nm. Zr‐PhyA was used to catalyze the mild and selective Meerwein–Ponndorf–Verley (MPV) reduction of various carbonyl compounds, e.g., of levulinic acid and its esters into γ‐valerolactone. Further studies indicated that both Zr and phosphate groups contribute significantly to the excellent performance of Zr‐PhyA.
Dual effect of chemical modification and polymer precoating of flax fibers on the properties of short flax fiber/poly(lactic acid) composites
Authors: Kodal Mehmet , Topuk Zeynep Demir , Ozkoc Guralp
Published: July 2015

Polymer precoated and chemically modified short flax fiber (SFF)/poly(lactic acid) (PLA) composites were successfully produced. The main focus of this study was to investigate the effects of the combinatorial use of chemical modification methods of flax fiber, such as alkaline treatment and silane coupling agents, together with polymer precoating as the film former on the physical and mechanical properties for PLA/SFF composites. The chemically modified flax fibers were characterized by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy. It was revealed from XRD analysis that alkaline treatment resulted in change in the cellulose I structure to the cellulose II structure because of the removal of the cementing non‐cellulosic components. The XPS analysis showed that the silane groups were successfully bonded to the surface of the flax fiber. As the film‐former application, PLA was coated on the surface of alkaline or silane‐treated flax fiber surfaces via a solution dipping process. The SFF content was kept constant at 25 wt % in the composites that were prepared by means of a 15 mL Xplore Instruments twin‐screw compounder. After melt processing, the positive effect of the sizing application on both the alkaline‐ and silane‐treated SFF was observed from the enhanced fiber length distribution. The mechanical properties were examined by means of tensile and impact tests and dynamic mechanical analysis. In addition, the thermal properties obtained from differential scanning calorimetry were discussed as a function of the fiber treatment method. The hydrolysis rate was determined by a weight loss test in a phosphate buffer solution. The results showed that in addition to the positive single influence of the silane coupling agent, the synergetic effect of the film former (i.e., precoated polymer) and silane treatment was observed to improve the performance of the composites. The hydrolysis rate of the polymer‐coated flax‐based composites was lower than that of uncoated flax fiber composites. In addition, polymer‐coated flax fibers could be easily processed like conventional chopped short‐glass‐fiber composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42564.
Synthesis and characterization of partially hydrolyzed polyacrylamide nanocomposite weak gels with high molecular weights
Authors: Xu Jingshui , Chen Denglong , Ke Yangchuan , Yang Li , Bai Xin , Zhang Guoliang , Zeng Zheling , Gao Wenshuai , Gong Deming
Published: July 2015

High‐molecular‐weight partially hydrolyzed polyacrylamide nanocomposite (HPAMNC) weak gels were synthesized and evaluated for their flooding behaviors in oil‐recovery applications. The structure, morphology, and properties of the obtained HPAMNC samples and their weak gels were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). XRD patterns clearly proved the exfoliation of the montmorillonite (MMT) layers in the polymer matrix; this was consistent with TEM analysis. The morphology of the HPAMNC was proven to be in a cross‐wire aggregated form by SEM analysis. The viscosity‐average molecular mass of the obtained HPAMNC was approximately 8.51 × 106 under the optimized MMT load at 1.0 wt %. The flooding experiments showed that the oil‐recovery rates in sand pack tubes with low and high permeability were enhanced by approximately 35.1 and 46.2%, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42626.
Synthesis of a montmorillonite‐supported titania nanocomposite with grafted cellulose as a template and its application in photocatalytic degradation
Authors: Man Xiaolin , Wu Ronglan , Lv Henghua , Wang Wei
Published: July 2015

We report a study on the synthesis of anatase titania (TiO2) particles with the sol–gel method at room temperature. We immobilized the particles on a grafted‐cellulose intercalated montmorillonite (MMT). This nanocomposite, cellulose‐g‐poly(4‐vinyl pyridine)/MMT/TiO2, could be applied in the photocatalytic degradation of organic pollutants efficiently because of the addition of a sorbent, the grafted cellulose. The synthesized nanocomposite was characterized with Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. Methyl orange was used as a model molecule to study photocatalytic degradation. The nanocomposite exhibited a better photocatalytic activity than in the absence of the grafted cellulose. The kinetics of the photocatalytic degradation could be described by pseudo‐first‐order rate law. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42627.