bluuebunny/crossref_metadata_2025_split huggingface dataset:
Allometry of the pyrophyticAristidain fire‐maintained longleaf pine–wiregrass ecosystems
Authors: Shearman Timothy M. , Varner J. Morgan , Robertson Kevin , Hiers J. Kevin 
Published: January 2019

Premise of the StudyAboveground biomass (AGB) of herbaceous vegetation is a primary source of fuel in frequent surface fires that maintain grasslands, savannas, and woodlands. Methods for nondestructively estimatingAGBare required to understand the mechanisms by which fuels affect fire behavior and the effects of time since the last burn. We developed allometric equations to estimateAGBin wiregrass (Aristida beyrichiana/A. stricta), a dominant bunchgrass inPinus palustrisecosystems and a key species for ecological restoration.MethodsWe collected wiregrass from North Carolina to Florida, across a range of time‐since‐last burn and site types. We tested 32 mixed effect models to see which predictors were best at predicting live, dead, and totalAGB. We also examined how time since burn (TSB) affected the live‐to‐dead ratio (LDR) using regression.Key ResultsWiregrassAGBwas found to increase with increasing latitude (relative to tussock volume), possibly due to an increase in precipitation, and was greater on more fertile clay soils and flatwoods than on sandy soils. TheLDRdecreased as a power function withTSB, resulting in rapid accumulation of dead, highly flammable, biomass in the fire‐free period.ConclusionsGreater biomass will support fires of higher intensity. Our models can be useful in the parameterization of future physics‐based models to predict fire behavior. Understanding the environmental variables that influence the allometry of wiregrass should help increase the precision ofAGBestimates and the subsequent effects on fire behavior and effects on neighboring vegetation.
A temporal shift in resource allocation facilitates flowering before leaf out and spring vessel maturation in precocious species
Authors: Savage Jessica A. 
Published: January 2019

Premise of the StudyNew growth in the spring requires resource mobilization in the vascular system at a time when xylem and phloem function are often reduced in seasonally cold climates. As a result, the timing of leaf out and/or flowering could depend on when the vascular system resumes normal function in the spring. This study investigated whether flowering time is influenced by vascular phenology in plants that flower precociously before they have leaves.MethodsFlower, leaf, and vascular phenology were monitored in pairs of precocious and non‐precocious congeners. Differences in resource allocation were quantified by measuring bud dry mass and water content throughout the year, floral hydration was modelled, and a girdling treatment completed on branches in the field.Key ResultsPrecocious flowering species invested more in floral buds the year before flowering than did their non‐precocious congeners, thus mobilizing less water in the spring, which allowed flowering before new vessel maturation.ConclusionsA shift in the timing of resource allocation in precocious flowering plants allowed them to flower before the production of mature vessels and minimized the significance of seasonal changes in vascular function to their flowering phenology. The low investment required to complete floral development in the spring when the plant vascular system is often compromised could explain why flowers can emerge before leaf out.
Phylogenetic inference in section Archerythroxylum informs taxonomy, biogeography, and the domestication of coca (Erythroxylum species)
Authors: White Dawson M. , Islam Melissa B. , Mason‐Gamer Roberta J. 
Published: January 2019

Premise of the StudyThis investigation establishes the first DNA‐sequence‐based phylogenetic hypothesis of species relationships in the coca family (Erythroxylaceae) and presents its implications for the intrageneric taxonomy and neotropical biogeography of Erythroxylum. We also identify the closest wild relatives and evolutionary relationships of the cultivated coca taxa.MethodsWe focused our phylogenomic inference on the largest taxonomic section in the genus Erythroxylum (Archerythroxylum O.E.Schulz) using concatenation and gene tree reconciliation methods from hybridization‐based target capture of 427 genes.Key ResultsWe show that neotropical Erythroxylum are monophyletic within the paleotropical lineages, yet Archerythroxylum and all of the other taxonomic sections from which we sampled multiple species lack monophyly. We mapped phytogeographic states onto the tree and found some concordance between these regions and clades. The wild species E. gracilipes and E. cataractarum are most closely related to the cultivated E. coca and E. novogranatense, but relationships within this “coca” clade remain equivocal.ConclusionsOur results point to the difficulty of morphology‐based intrageneric classification in this clade and highlight the importance of integrative taxonomy in future systematic revisions. We can confidently identify E. gracilipes and E. cataractarum as the closest wild relatives of the coca taxa, but understanding the domestication history of this crop will require more thorough phylogeographic analysis.
Molecular analysis of an ancient Thule population at Nuvuk, Point Barrow, Alaska
Authors: Tackney Justin , Jensen Anne M. , Kisielinski Caroline , O'Rourke Dennis H. 
Published: January 2019

AbstractObjectivesThe North American archaeological record supports a Holocene origin of Arctic Indigenous peoples. Although the Paleo‐Inuit were present for millennia, archaeological and genetic studies suggest that modern peoples descend from a second, more recent tradition known as the Neo‐Inuit. Origins of the Neo‐Inuit and their relations to the earlier and later Indigenous peoples are an area of active study. Here, we genetically analyze the maternal lineages present at Nuvuk, once the northernmost community in Alaska and located in a region identified as a possible origin point of the Neo‐Inuit Thule. The cemetery at Nuvuk contains human remains representing a nearly one thousand year uninterrupted occupation from early Thule to post‐contact Iñupiat.Materials and methodsWe selected 44 individuals from Nuvuk with calibrated dates between 981 AD and 1885 AD for molecular analysis. We amplified and sequenced the hypervariable segment I of the mitogenome. We compared the Nuvuk data with previously published sequences from 68 modern and ancient communities from across Asia and North America. Phylogeographic analyses suggest possible scenarios of Holocene Arctic and sub‐Arctic population movements.ResultsWe successfully retrieved sequence data from 39 individuals. Haplogroup frequencies in Nuvuk were typed as 66.7% A2b1, 25.6% A2a, and 7.7% D4b1a2a1a. These results suggest that the population at Nuvuk was closest to the ancient Thule and modern Inuit of Canada, and to the Siberian Naukan people. We confirm that haplogroups A2a, A2b1, D2a, and D4b1a2a1a appear at high frequency in Arctic and sub‐Arctic populations of North America and Chukotka. Sister clades D2b and D4b1a2a1b are present in Asian and Eastern European populations.DiscussionThe ancient mitochondrial sequences from Nuvuk confirm the link between the North Slope and the Thule who later spread east, and the maternal discontinuity between the Neo‐Inuit and Paleo‐Inuit. We suggest haplogroups A2a, A2b, and D4b1a2a1a are linked to the ancestors of the Thule in eastern Beringia, whereas the D2 and D4b1a2a1 clades appear to have Asian Holocene origins. Further Siberian and Alaskan genomes are necessary to clarify these population migrations beyond a simple two‐wave scenario of Neo‐Inuit and Paleo‐Inuit.
Describing the children's body shape by means of Geometric Morphometric techniques
Authors: Medialdea Laura , Bazaco Cayetana , D'Angelo del Campo Manuel Domingo , Sierra‐Martínez Carlos , González‐José Rolando , Vargas Antonio , Marrodán María Dolores 
Published: January 2019

AbstractIntroductionLarge shape variations take place during the growth process of children, including quantitative mass and size increase plus qualitative changes in their body shape. The aim of the present study is to apply Geometric Morphometric techniques in order to visualize and quantify such body shape differences in healthy children aged 6–59 months with optimal nutritional status.Materials and methodsAnthropometrical measurements of weight, height, and middle‐upper arm circumference were used to assess nutritional status on a sample of 258 Senegalese (n = 154) and Spanish (n = 104) children. A set of 36 anatomical and/or osteologically‐based landmarks were identified on the body of the children along with 108 semi‐landmarks used to capture curvature attributes on the frontal view of the body image. A specific method was developed to place and photograph children, as well as to locate landmarks, treat images and calculate semi‐landmarks. Shape differences among children were analyzed in terms of age, sex, and population origin, taking into consideration allometry effects.ResultsOur results indicate significant differences in shape and size for all the three factors under study before removing size effect (p < .0001), and in shape after the size correction (p < .01). Only the ontogenetic effect persisted in the size of studied individuals after size‐effects correction (p < .0001). Morphometric significant differences were described regarding age for PC1 and population origin in PC2 before removing size effect. Between‐population morphometric differences were sorted along PC1 after size correction.DiscussionGeometric Morphometric techniques are useful to study morphometric changes in the anterior whole‐body view of children under 5 years old, allowing a precise description of shape changes observed when age and population origin are considered.
Comparing the effectiveness of training course formats for point‐of‐care ultrasound in the third trimester of pregnancy
Authors: Westerway Susan Campbell 
Published: January 2019

AbstractIntroductionThe availability of obstetric point‐of‐care ultrasound (PoCUS) services has been shown to improve pregnancy outcomes in regional and remote areas both in Australia and around the world. There is an increasing demand for efficient, cost‐effective PoCUS courses for monitoring the fetus in the third trimester of pregnancy.AimTo compare the effectiveness of targeted PoCUS courses provided for health professionals that assess the fetus during the third trimester of pregnancy.MethodThe skill‐teaching curriculum and competency outcomes of six obstetric PoCUS courses were compared. There were 55 learners with no prior ultrasound experience including 23 with English as a second language. Course duration ranged from 4 to 18 h, didactic lecture time up to 6 h and practical scanning sessions of 3–12 h. Learner/tutor ratio varied from 1:1 to 6:1. All courses included the teaching of knobology, image optimisation and probe manipulation. Practical sessions included supervised scanning of ultrasound phantoms and scanning women in the third trimester of pregnancy. The teaching outcomes that were assessed included image optimisation, determination of fetal lie, fetal heart rate, measuring the single deepest pocket of amniotic fluid, identifying the placental position and basic fetal biometry. The same pre‐ and post‐course multiple choice test and course evaluation forms were used for every programme.ResultsAll participants achieved the limited course objectives, regardless of the differences in the course formats.ConclusionThis study confirms that obstetric PoCUS courses can provide the initial basic knowledge and scanning skills required to perform limited scope third‐trimester scanning.
Clarithromycin for the treatment of adult chronic rhinosinusitis: a systematic review and meta‐analysis
Authors: Huang Zhenxiao , Zhou Bing 
Published: January 2019

BackgroundThe aim of this systematic review (SR) was to assess the safety and efficacy of oral clarithromycin for the treatment of chronic rhinosinusitis (CRS).MethodsThis SR and meta‐analysis was conducted based on the recommendations outlined in the Cochrane Handbook for SR of Interventions. The protocol was registered on PROSPERO, an international prospective register of SRs. English and Chinese electronic databases were searched, and only randomized controlled trials were included.ResultsSeventeen studies with 1738 patients were included. Eleven studies evaluated whether adding oral clarithromycin to intranasal steroid spray with or without nasal saline irrigation was more effective than intranasal steroid spray alone. This combined treatment regimens statistically significantly improve clinical symptoms in the medium term (1 to 3 months), the endoscopic and computed tomography (CT) scores in both the short term (<1 month) and medium term, and clinical symptoms and the endoscopic score in the long term (>3 months). The incidence of adverse events did not increase with the use of this combination therapy. No significant difference was identified between treatment with oral clarithromycin and intranasal steroid spray alone groups in term of symptoms, endoscopic score, and CT score.ConclusionFor the treatment of CRS, adding oral clarithromycin to intranasal steroid spray with or without nasal saline irrigation may achieve better results than using intranasal steroid spray with or without nasal saline irrigation. There is insufficient evidence to confirm that oral clarithromycin alone may have similar efficacy as nasal glucocorticoid spray alone. High‐quality evidence in this area is needed.
Morphologies, crystallization, and mechanical properties of PLA‐based nanocomposites: Synergistic effects of PEG/HNTs
Authors: Jia Shikui , Yu Demei , Wang Zhong , Zhang Xianyong , Chen Ligui , Fu Lei 
Published: January 2019

ABSTRACTIn this study, the compounding modifier poly(ethylene glycol)/halloysite nanotubes (PEG/HNTs) was prepared by supersonic vibration and dynamic vacuuming. A series of poly(lactic acid) (PLA)/PEG and PLA/PEG/HNT composites were fabricated using a twin‐screw extruder. Fourier transform infrared spectroscopy indicated that the hybrid between PEG and HNTs had no evident chemical interaction via supersonic vibration and dynamic vacuuming. The dispersed morphology of the compounding modifier in the PLA matrix was tested by high‐resolution scanning electronic microscopy and transmission electron microscopy. The results showed that the low content of PEG/HNTs presented a good dispersion morphology. The binding energy of the PLA‐based composites was studied through contact angle measurements. The results showed that PEG and PEG/HNTs can decrease the water contact angle of PLA, and that the binding energy between PEG and HNTs is higher than that of PLA/HNTs, which leads to more location of HNTs in the PEG phase. The crystallization behavior of PLA‐based composites was examined by wide‐angle X‐ray diffraction and differential scanning calorimetry. The results suggested that the addition of PEG and PEG/HNTs effectively enhanced the crystallization of PLA and that the diffraction peak intensity of the PLA‐based composites reached a maximum when the content of PEG/HNTs was 1.2 wt %. The spherulite morphology indicated that the addition of PEG resulted in perfect spherulites. The mechanical properties of PLA‐based composites were analyzed with a universal testing machine and impact tester, which confirmed that the tensile strength and impact strength of the PLA‐based composites increased slightly when the content of the PEG/HNT modifier was 1.2 wt %, while the tensile modulus of the PLA‐based composites increased distinctly. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47385.
Effect of different coupling agents on chemical structure and physical properties of vinyl acetate/wood polymer composites
Authors: Ghorbani Maryam , Aghmashadi Zahra Asghari , Amininasab Seyed Mojtaba , Abedini Raoufeh 
Published: January 2019

ABSTRACTThis research investigated the effect of chemical modification with vinyl acetate in combination with different coupling agents (maleic anhydride, 3‐(trimethoxysilyl) propyl methacrylate and glycidyl methacrylate) on chemical structure and physical properties of poplar wood. Samples were impregnated with chemicals using vacuum‐pressure method following by vinyl acetate. Fourier transform infrared analysis results confirmed cell wall chemical modification, that was more obvious for glycidyl methacrylate ones. Dimensional stability of resultant composite enhanced via crosslink formation between modified wood and polymer, which affected by cell wall modification rather than in situ polymerization. In comparison of coupling agents, glycidyl methacrylate mostly improved the physical properties of wood as well as combined modified composites. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47467.
Continuous post‐polycondensation of high‐viscosity poly(ethylene terephthalate) in the molten state
Authors: Wang YongJun , Chen ShiChang , Guang ShanShan , Wang Ying , Zhang XianMing , Chen WenXing 
Published: January 2019

ABSTRACTTime‐resolved rheometry and size exclusion chromatography system [advanced polymer chromatography (APC)‐multi‐angle laser light scattering (MALLS)‐refractive index detector (RID)] were employed to investigate post‐polycondensation process of nonstirred high‐viscosity poly(ethylene terephthalate) (PET) of molten film forming by high‐flow inert gas sweeping at atmospheric pressure. In view of chemical reaction kinetics together with mass transfer to adjust reactive parameters, including moisture content of the sample, temperature, concentration of the active groups, residence time, and mass transfer factor, this work aims to distinguish the different reactions in reprocessing of high‐viscosity PET. Results indicated that hydrolysis is observed initially before thermal degradation and polycondensation reactions on remelting process. Promotion of thermal degradation is stronger than polycondensation with the increase in temperature. Fiber‐grade PET exhibits polycondensation as the dominant reaction at 275 °C in a reasonable reaction time, which leads to the increase of average molecular weight and the phenomenon of double distribution proved by APC‐MALLS‐RID system. However, the average molecular weight of industrial yarn‐grade PET is very difficult to improve when the thermal degradation reaction is not effectively inhibited. Importantly, the experimental study of the interfacial mass‐transfer area and mass‐transfer intensification demonstrated that mass transfer is the rate‐determining factor for the overall post‐polycondensation of high‐viscosity melt. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47484.
Understanding the oxygen barrier property of highly transparent poly(lactic acid)/benzoxazine composite film by analyzing the UV‐shielding performance
Authors: Zhang Tao , Yu Qiu‐Yan , Yang Hai‐Tang , Wang Jia‐Jun , Li Xin‐Bao 
Published: January 2019

ABSTRACTThis work reports a new composite film from poly(lactic acid) (PLA) and benzoxazine (BOZ). Introduction of BOZ to PLA simultaneously improves the ultraviolet (UV)‐shielding and oxygen barrier properties, which show strong dependence on the content of BOZ. The PLA film demonstrates almost no UV‐shielding capacity, but the PLA/BOZ composite film can reach UV‐shielding capacity of 98.3% at 350 nm. The corresponding average oxygen permeability coefficient of the composite film is as low as 1.168 × 10−18 m3 m m−2 s−1 Pa−1, which is significantly lower than that of PLA (5.540 × 10−17 m3 m m−2 s−1 Pa−1). Meanwhile, the composite film retains visible transparency ≥90.0% at 550 nm. The relationship and its implication between the oxygen barrier performance and UV‐shielding capacity are discussed, which propose new guidelines for the development of high barrier PLA film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47510.
Effect of nonsolvent additives on PES ultrafiltration membrane pore structure
Authors: Xiang Jun , Hua Xinxin , Dong Xingfeng , Cheng Penggao , Zhang Lei , Du Wei , Tang Na 
Published: January 2019

ABSTRACTDifferent nonsolvent additives, namely, diethylene glycol, n‐butyl alcohol (NBA), and ethylene glycol monomethyl ether, were added into the casting solution (polyethersulfone/dimethylformamide/lithium chloride) to prepare ultrafiltration (UF) membrane via phase inversion. The effects of different additives and their concentration on the pore structure of the prepared UF membrane were studied. The cross‐sectional morphology of the membrane was observed via scanning electron microscopy. The addition of nonsolvent additives improved the large‐cavity structure of the membrane. When the additive was low‐content NBA (1–3 wt %), the membrane pore structure transformed from large‐cavity structure to fully sponge‐like structure. When the content of additive NBA was 3 wt %, the flux of the prepared UF membrane was 130.45 L (m−2 h−1), the rejection of PEG20000 was 95.54% and the flux remained high at 4 bar in long‐term stability test. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47525.
Effect of conductive polyaniline in thermoplastic natural rubber blends on the mechanical, thermal stability, and electrical conductivity properties
Authors: Zailan Farrah Diyana , Chen Ruey Shan , Shahdan Dalila , Ahmad Sahrim 
Published: January 2019

ABSTRACTThis research was conducted to fabricate thermoplastic natural rubber/polyaniline (TPNR/PANI) blends via melt blending method using an internal mixer and followed by compression molding. The effects of PANI contents between 1 and 5 wt % PANI in the TPNR blends on the mechanical properties, thermal stability, electrical conductivity (impedance), and morphology observation were investigated. The TPNR/3 wt % PANI sample exhibited the highest tensile strength (3.7 MPa), elongation at break (583%), flexural strength (1.8 MPa), flexural modulus (37.0 MPa), and impact strength (7.1 kJ m−2). From the aspect of thermal properties, it was found that with the addition of PANI, the thermal stability of the TPNR/PANI increased. Comparing to nonconductive TPNR sample, the incorporation of PANI promoted the electrical conductivity characteristic to PANI‐filled TPNR blends which showing a magnitude order of 10−9S cm−1. Scanning electron microscopy micrograph revealed the good distribution of PANI at the optimum content (3 wt % PANI) in the TPNR blends and the good interaction between TPNR and PANI. It can be concluded that the TPNR blends incorporated with a low loading of PANI could be a newly good conductive material. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47527.
Aggregation‐Induced Emission for Visualization in Materials Science
Authors: Li Kaitao , Lin Yanjun , Lu Chao 
Published: January 2019

AbstractFluorescent imaging techniques have attracted much attention as a powerful tool to realize the visualization of structural and morphological evolution of various materials. However, the traditional fluorescent dyes usually suffered from aggregation‐caused quenching, which severely limits the visualization results. In contrast, aggregation‐induced emission (AIE) molecules with high quantum yields in the condensed state showed great opportunities for imaging techniques. In this feature article, recent progresses in visualization with AIE molecules are discussed. Assembly processes including crystallization, gelation process, and dissipative assembly have been observed. To better study information obtained regarding the processes, visualization during reactions, phase transitions, and molecular motions are successfully presented. Based on these successes, AIE molecules were further applied for phase recognition, macro‐dispersion evaluation, and damage detection. Finally, we also present the outlook and perspectives, in our opinion, for the development of visualization by AIE molecules.