bluuebunny/crossref_metadata_2025 huggingface dataset:
The center of science in Africa: Timbuctoo
Authors: Özalp Mehmet Sıddık
Published: September 2024

Timbuctoo, situated within the borders of the Republic of Mali today, is located in the central region of Mali, at a point where the Niger River bends. The history of the city extends back to the late 11th century. Timbuctoo derives its name from an elderly woman named Buktu, who lived along the banks of the Niger River. The former name of Timbuctoo was Tumbukt. Additionally, it has been become famous with epithets such as “the Marvelous City”, “the Legendary City”, “the Jewel of the Desert,”, “the City of Cultural Light”, “the Golden City” and “the City of 333 Saints”. Becoming Africa’s center of learning, particularly from the 13th century onwards, Timbuctoo has emerged as one of West Africa's most renowned cities. Recognized as a significant capital of the Islamic world, Timbuctoo’s population consists entirely of Muslims. Timbuktu has served as a bridge between North Africa and West Africa, nurturing numerous scholars and becoming a crucial center of cultural dynamics. Through institutions like the University of Sankore, Timbuctoo has become a hub for Islam, science, and literature, producing distinguished scholars. In this context, Timbuctoo will be examined as a significant center of learning in Africa, presented to the Turkish academic community. The study will explore topics such as “Introduction”, “The Timbuctoo in brif”, “The Sankore Madrasah” and “The Scholars of Timbuctoo”. In the conclusion part, the necessary analyzes will be made and the study will be completed by making recommendations.
ETNOMATEMÁTICA NO CONTEXTO DA FORMAÇÃO DE PROFESSORES DE MATEMÁTICA: UMA ANÁLISE DE TESES E DISSERTAÇÕES BRASILEIRAS
Authors: Pereira Antônia Lília Soares , Leite Kécio Gonçalves
Published: September 2024

Este estudo possui um viés contributivo no que concerne à valorização de práticas culturais existentes para promover o reconhecimento da diversidade de saberes culturais de comunidades tradicionais por meio da etnomatemática. O objetivo deste estudo é apresentar as abordagens da etnomatemática na formação de professores que ensinam Matemática, a partir de uma análise de teses e dissertações produzidas por pesquisadores brasileiros. A metodologia adotada consiste na análise de pesquisas que relacionam a etnomatemática com a formação de professores de Matemática, conforme uma verificação realizada por meio de uma revisão bibliográfica das pesquisas indexadas no Catálogo de Teses e Dissertações da Capes e no Google Scholar. Para proceder à análise desses textos acadêmicos, optou-se pela utilização do software MAXQDA24. Como resultados, aponta-se que a amostra final da coleta de dados resultou em 60 estudos que apresentavam relevância para esta pesquisa. A amostra das pesquisas analisadas enfatiza que o conhecimento matemático pode ocorrer de forma integrada às especificidades socioculturais dos diferentes grupos culturais, inclusive sob o aspecto da regionalização. Firmam-se abordagens da etnomatemática para o envolvimento de experiências pedagógicas de forma reflexiva e para o reconhecimento de matemáticas que as diferentes comunidades produzem. Para um aprofundamento da pesquisa, torna-se necessária uma análise dimensional dos mapeamentos dos saberes e fazeres socioculturais regionalizados com base na etnomatemática. Desse modo, sob o enfoque do contexto sociocultural e étnico-racial, as pesquisas analisadas possuem um viés colaborativo para a regionalização da formação de professores de matemática, com base na valorização dos saberes de comunidades e de sociedades tradicionais.
A Model for Surfacing Hidden Collections: The Rescuing Texas History Mini-Grant Program at The University of North Texas Libraries
Authors: McIntosh Marcia , Mangum Jacob , Phillips Mark E.
Published: September 2024

The University of North Texas Libraries (UNT Libraries) have directed a digitization service called Rescuing Texas History (RTH) with the goals of helping local and state-level cultural heritage institutions and private owners digitize their materials. RTH allows UNT Libraries to develop mutually-beneficial relationships with regional organizations while preserving and providing access to a large variety of at-risk historical items in The Portal to Texas History digital repository. The model described in this paper will explain the methods and lessons learned over the years of conducting the program. RTH’s overall structure serves as a model for sustainable large-scale digitization initiatives.
ABORDAGENS TERAPÊUTICAS NO TRANSTORNO DO ESPECTRO AUTISTA (TEA): UMA REVISÃO INTEGRATIVA SOBRE NOVAS TERAPIAS, IMPACTO FAMILIAR E DIAGNÓSTICO PRECOCE
Authors: Barbosa Charles de Moura , Gondim Danilo Augusto Teles , Silvestre Danubio Silva , Souza Deivid Monteiro , Ribeiro Egiany Guedes , Moura Fabiano Barros , Oliveira Gabriela Alves de , Brock Karla Simone de Brito , Bataglion Ludson , Roxinol Luiz Michel , Azevedo Mônica Nóbrega de , Caldas Morgana Bezerra Bispo , Costa Rogério Mateus , Costa Viviane Tontini , Brock Yale de Brito
Published: September 2024

Autism Spectrum Disorder (ASD) is a complex neuropsychiatric condition that affects social, cognitive, and behavioral development. This article presents an integrative review of new therapeutic approaches for managing ASD, its impact on family quality of life, and the importance of early diagnosis. Behavioral, pharmacological, and complementary interventions, such as Applied Behavior Analysis (ABA) and music therapy, have proven effective in improving symptoms and enhancing children’s skills. Family support is also essential in reducing caregivers’ emotional and financial burdens, while early diagnosis is critical for the success of interventions, maximizing the child’s developmental potential. This study highlights the importance of an integrated approach involving families and healthcare professionals, focusing on personalized treatment and accessibility to diagnosis and interventions.
Linking Objects for Traumatic Companion Animal Loss
Authors: Pahl Nelson
Published: September 2024

A thirty-seven-year-old female suffers traumatic loss when a pack of urban coyotes attacks, mutilates, and kills her 12-year-old pocket beagle, Boogie. Female client endures problematic grief seven-plus months in nature. Among many other symptoms, she experiences intense sorrow, preoccupation with the deceased, and functional impairment. Client and I have been addressing her grief through a series of weekly, 90-minute sessions. In this fourth session, I introduce and articulate the experiential concept of linking objects.
Digital Dialog Insights 2022: Status Quo, Trends und Perspektiven im digitalen Dialog-Marketing
Authors: Eichsteller Harald , Seitz Jürgen
Published: September 2024

Die 11. Ausgabe der Digital Dialog Insights zeigt Status Quo, Trends und Perspektiven im digitalen Dialog-Marketing auf. Im Fokus stehen die Themenfelder E-Commerce, Commerce Media & Marketing, Post-Cookie und Web3 & Metaverse. 10 Thesen: Everywhere Commerce breitet sich aus; Commerce Media ist mehr als Retail Media; Post-Cookie-Vorbereitungen weiter unzureichend; Contenxtual Targeting und First Party Identifier profieren von Cookiegeddon; D2C wir von Marken adaptiert; in der Krise holt der Preis im Marketing-Mix auf; Digitale Produkte mit großem Potenzial; Digitaler Vertrieb wird kompetitiver; Digitaler Luxus steht in den Startlöchern; Etablierte Marken mit Potenzial für digitale Produkte.
Justiça integral e esperança cristã na escatologia de J. Ratzinger
Authors: Antônio Brustolin Leomar , Teles Eleandro
Published: September 2024

Este artigo reflete sobre uma questão colocada por Joseph Ratzinger em sua obra sobre a escatologia: em que medida a esperança cristã, apresentada a partir de temas tradicionais como o juízo final, pode ter alguma importância para o mundo de hoje? Mais exatamente: em que sentido a esperança na justiça escatológica pode ou deve ter implicações para a práxis cristã? Trata-se de buscar o sentido da justiça divina, a partir de uma perspectiva escatológica, procurando apontar também as consequências teológicas e práticas decorrentes dessa esperança. A partir de Ratzinger, busca-se uma aproximação teológica ao tema, em diálogo com outros autores que tocam atemática da relação entre escatologia e práxis. Por fim, busca-se relacionar a visão teológica de uma justiça integral e criativa, reconciliadora e restauradora, com algumas reflexões e iniciativas que surgem no âmbito jurídico, a partir de autores que refletem  sobre a atual crise do Direito positivo e a necessidade de se criar novas relações de justiça na sociedade, dentro de um modelo restaurativo.
El viento de Dios está soplando en y desde el sur del Sur
Authors: Maria Galli Carlos
Published: September 2024

La Iglesia siguió un largo camino durante cinco siglos en América Latina y El Caribe, y hoy vive un momento especial de su marcha misionera. Esta nueva etapa no comenzó con el actual obispo de Roma, sino que recorrió el último medio siglo. Tuvo un inicio real y simbólico en el Concilio Vaticano II, si bien comenzó años antes. Últimamente, la Conferencia de Aparecida es un marco importante para entender el significado del actual pontificado. Este artículo enuncia de forma sintética un conjunto de procesos en curso, sin desarrollar sus contenidos. La mayoría de estas situaciones se podía advertir desde hace años, antes del Papa del fin del mundo. Pero, hoy, Francisco es un icono de la hora de la Iglesia latinoamericana con tonada argentina. En la secuencia, el texto distribuye los procesos y las claves en tres grupos: los nueve primeros son sobre América Latina (1-9); los siete siguientes sobre nuestra Iglesia (10-18); los nueve últimos sobre Francisco (19-30).
“Uma Igreja pobre e para os pobres”: abordagem teológico-pastoral
Authors: De Aquino Júnior Francisco
Published: September 2024

No centro das preocupações e orientações pastorais do novo bispo de Roma estão o cuidado e o compromisso com os pobres, oprimidos e fracos deste mundo, expressos nos termos de “uma Igreja pobre para os pobres”. Essa é uma marca fundamental da Igreja de Jesus Cristo que, embora nunca tenha se perdido completamente da Tradição da Igreja, foi retomada com muita força e criatividade pelo Concílio Vaticano II, com João XXIII e o grupo Igreja dos pobres, e, sobretudo, pela Igreja latino-americana, com as conferências episcopais de Medellín e Puebla e com a teologia da libertação. Partindo da reflexão desenvolvida no Concílio Vaticano II e na Igreja da América Latina, apresentaremos o modo como Francisco compreende e propõe a opção pelos pobres para toda Igreja e identificaremos as convergências e diferenças entre Francisco e a teologia da libertação acerca do projeto de “uma Igreja pobre para os pobres”.
TEKSTİL SEKTÖRÜNDE RİNG MAKİNESİ SİPARİŞ ÇİZELGELEME PROBLEMİ: HAZILIK SÜRELERİNİN MİNİMİZASYONU
Authors: Alakaş Hacı Mehmet , Özdil Selma , Gür Şeyda
Published: September 2024

Siparişlerin zamanında teslim edilmesi ve sürdürülebilirlik için esneklik önemli bir faktördür. Esnekliğin önündeki engellerden biri de üretim esnasında ihtiyaç duyulan hazırlık süreleridir. Hazırlık sürelerinin yüksekliği nedeniyle firmalar esnek üretim yapamadığı gibi üretim kayıpları da yaşamaktadırlar. Bu çalışmada ürün yaşam döngülerinin kısalması ile esnekliğin önemli olduğu tekstil sektöründe ring makinelerinde üretim çizelgeleme problemi ele alınmıştır. Ring makinelerinin hazırlık sürelerine etki eden faktörlerden biri de ürünlerin birbirleri arasındaki değişim sürelerinin farklılaşmasıdır. Önerilen matematiksel model ile birbirleri arasında hazırlık süresi az olan siparişlerin aynı makineye atanması hedeflenmiştir. Ring makinelerinin ve siparişlerin özellikleri dikkate alınmış ve siparişlerin uygun makinelere atanması sağlanmıştır. Önerilen modelle makinelerdeki hazırlık süresinin azaltılması amaçlanmıştır. Böylelikle hazırlık için kullanılan sürenin üretim için kullanılabilecektir ve üretim miktarının artırılması sağlanacaktır. Bir gerçek örnek üzerinden model test edilmiştir. Farklı senaryolar ile siparişlerin atamaları yapılarak üretim planlama için öneriler sunulmuştur. Benzer yapıdaki farklı üretim süreçleri için örnek bir uygulama sunulmuştur.
Uncertainty-modulated prediction errors in cortical microcircuits
Authors: Wilmes Katharina A , Petrovici Mihai A , Sachidhanandam Shankar , Senn Walter
Published: September 2024

Understanding the variability of the environment is essential to function in everyday life. The brain must hence take uncertainty into account when updating its internal model of the world. The basis for updating the model are prediction errors that arise from a difference between the current model and new sensory experiences. Although prediction error neurons have been identified in layer 2/3 of diverse brain areas, how uncertainty modulates these errors and hence learning is, however, unclear. Here, we use a normative approach to derive how uncertainty should modulate prediction errors and postulate that layer 2/3 neurons represent uncertainty-modulated prediction errors (UPE). We further hypothesise that the layer 2/3 circuit calculates the UPE through the subtractive and divisive inhibition by different inhibitory cell types. By implementing the calculation of UPEs in a microcircuit model, we show that different cell types can compute the means and variances of the stimulus distribution. With local activity-dependent plasticity rules, these computations can be learned context-dependently, and allow the prediction of upcoming stimuli and their distribution. Finally, the mechanism enables an organism to optimise its learning strategy via adaptive learning rates.
ATP burst is the dominant driver of antibiotic lethality in Mycobacterium smegmatis
Authors: Lodhiya Tejan , Palande Aseem , Veeram Anjali , Larrouy-Maumus Gerald , Beste Dany JV , Mukherjee Raju
Published: September 2024

Antibiotic-tolerant bacteria, due to their unique physiology, are refractory to antimicrobial killing and pose challenges for infection control. Incomplete knowledge of how bactericidal antibiotics work, limits our understanding of partial resistance due to phenotypic tolerance in mycobacteria, a driver for developing genetic resistance. Using proteomics,
13
C isotopomer analysis, genetic and biochemical assays, we investigated the physiological response of
M. smegmatis
challenged with aminoglycoside and fluoroquinolone antibiotics. Two distinct classes of antibiotics elicited remarkably similar responses and increased flux through the TCA cycle, causing enhanced respiration, ROS generation, and ATP burst. We observed that excessive ATP levels and not ROS, dominantly contributes to cidality, which may in part be, conferred by sequestration of divalent metal ions by ATP. Consequently,
13
C isotope tracing indicated TCA cycle flux deviation from its oxidative arm as a bacterial adaptive mechanism, which also included activated intrinsic resistance and a higher propensity to develop antibiotic resistance. Our study provides a new understanding of the intricate mechanisms of antibiotic-induced cell death and expands the current paradigm for antibiotic action.
Suppression of EIF4G2 by miR‐379 potentiates the cisplatin chemosensitivity in nonsmall cell lung cancer cells
Authors: Hao Guang‐jun , Hao Hai‐jun , Ding Yan‐hui , Wen Hui , Li Xiao‐feng , Wang Qian‐ru , Zhang Bing‐bing
Published: January 2017

Although microRNAs and EIF4G2 are both known to play pivotal roles in cancer progression, it remains unknown whether these pathways regulate chemosensitivity in a coordinated manner. Here, we show that miR‐379 expression is significantly downregulated in chemoresistant nonsmall cell lung cancer (NSCLC) tissues and cells. Manipulation of miR‐379 levels could alter the in vitro and in vivo cisplatin (CDDP) resistance in lung cancer (LCa) cells. Mechanistically, miR‐379 potentiated LCa chemosensitivity via modulation of CDDP‐induced apoptosis by directly targeting the EIF4G2 3′UTR. Additionally, we observed an inverse correlation between miR‐379 and EIF4G2 expression in LCa tissues from patients with CDDP‐based chemotherapy. Together, our findings shed new light on the potential involvement of miR‐379/EIF4G2 cascade in the pathogenesis of CDDP resistance in LCa.
Seismic evidence that black smoker heat flux is influenced by localized magma replenishment and associated increases in crustal permeability
Authors: Arnoux Gillean M. , Toomey Douglas R. , Hooft Emilie E. E. , Wilcock William S. D. , Morgan Joanna , Warner Mike , VanderBeek Brandon P.
Published: January 2017

Hydrothermal circulation at mid‐ocean ridges is responsible for ~25% of Earth's heat flux and controls the thermal and chemical evolution of young oceanic crust. The heat flux of black smoker hydrothermal systems is thought to be primarily controlled by localized magma supply and crustal permeability. Nevertheless, magma chamber characteristics and the nature of crustal permeability beneath such systems remain unclear. Here we apply three‐dimensional full‐waveform inversion to seismic data from the hydrothermally active Endeavour segment of the Juan de Fuca Ridge to image the upper crust in high resolution. We resolve velocity variations directly above the axial magma chamber that correlate with variations in seismicity, black smoker heat flux, and the depth of the axial magmatic system. We conclude that localized magma recharge to the axial magma lens, along with induced seismogenic cracking and increased permeability, influences black smoker heat flux.
On the role of ice‐nucleating aerosol in the formation of ice particles in tropical mesoscale convective systems
Authors: Ladino Luis A. , Korolev Alexei , Heckman Ivan , Wolde Mengistu , Fridlind Ann M. , Ackerman Andrew S.
Published: January 2017

Over the decades, the cloud physics community has debated the nature and role of aerosol particles in ice initiation. The present study shows that the measured concentration of ice crystals in tropical mesoscale convective systems exceeds the concentration of ice nucleating particles (INPs) by several orders of magnitude. The concentration of INPs was assessed from the measured aerosol particle concentration in the size range of 0.5 to 1 µm. The observations from this study suggest that primary ice crystals formed on INPs make only a minor contribution to the total concentration of ice crystals in tropical mesoscale convective systems. This is found by comparing the predicted INP number concentrations with in situ ice particle number concentrations. The obtained measurements suggest that ice multiplication is the likely explanation for the observed high concentrations of ice crystals in this type of convective system.
A statistical analysis of sporadic E layer occurrence in the midlatitude China region
Authors: Zhou Chen , Tang Qiong , Song Xiaoxiao , Qing Haiyin , Liu Yi , Wang Xiang , Gu Xudong , Ni Binbin , Zhao Zhengyu
Published: January 2017

A statistical analysis of sporadic E layer recorded from September 2011 to September 2015 at four Chinese ionospheric sounding stations of Mohe (122.37°E, 53.50°N), Beijing (116.25°E, 40.25°N), Wuhan (114.61°E, 30.53°N), and Hainan (109.13°E, 19.52°N) is presented to investigate the characteristics of sporadic E layer at the middle latitudes over China. The occurrence of the sporadic E layer in midlatitude China region shows strong dependence on local time and season, consistent with previous studies. The occurrence of the midlatitude sporadic E layer is prominent at local daytime in summer season. The results also reveal that the postsunset sporadic E layer is statistically pronounced in midlatitude China region, possibly related to the nighttime midlatitude E region irregularities. The midlatitude sporadic E layer is modulated by atmospheric tidal waves and planetary waves at different latitudes. The occurrence of the midlatitude sporadic E layer also tends to increase with the level of geomagnetic activity on the basis of both the statistical analysis and case study.
Air‐sea heat flux climatologies in the Mediterranean Sea: Surface energy balance and its consistency with ocean heat storage
Authors: Song Xiangzhou , Yu Lisan
Published: January 2017

This study provides an analysis of the Mediterranean Sea surface energy budget using nine surface heat flux climatologies. The ensemble mean estimation shows that the net downward shortwave radiation (192 ± 19 W m−2) is balanced by latent heat flux (−98 ± 10 W m−2), followed by net longwave radiation (−78 ± 13 W m−2) and sensible heat flux (−13 ± 4 W m−2). The resulting net heat budget (Qnet) is 2 ± 12 W m−2 into the ocean, which appears to be warm biased. The annual‐mean Qnet should be −5.6 ± 1.6 W m−2 when estimated from the observed net transport through the Strait of Gibraltar. To diagnose the uncertainty in nine Qnet climatologies, we constructed Qnet from the heat budget equation by using historic hydrological observations to determine the heat content changes and advective heat flux. We also used the Qnet from a data‐assimilated global ocean state estimation as an additional reference. By comparing with the two reference Qnet estimates, we found that seven products (NCEP 1, NCEP 2, CFSR, ERA‐Interim, MERRA, NOCSv2.0, and OAFlux+ISCCP) overestimate Qnet, with magnitude ranging from 6 to 27 W m−2, while two products underestimate Qnet by −6 W m−2 (JRA55) and −14 W m−2 (CORE.2). Together with the previous warm pool work of Song and Yu (2013), we show that CFSR, MERRA, NOCSv2.0, and OAFlux+ISCCP are warm‐biased not only in the western Pacific warm pool but also in the Mediterranean Sea, while CORE.2 is cold‐biased in both regions. The NCEP 1, 2, and ERA‐Interim are cold‐biased over the warm pool but warm‐biased in the Mediterranean Sea.
Impact of recently upwelled water on productivity investigated using in situ and incubation‐based methods in Monterey Bay
Authors: Manning Cara C. , Stanley Rachel H. R. , Nicholson David P. , Smith Jason M. , Timothy Pennington J. , Fewings Melanie R. , Squibb Michael E. , Chavez Francisco P.
Published: January 2017

Photosynthetic conversion of
to organic carbon and the transport of this carbon from the surface to the deep ocean is an important regulator of atmospheric
. To understand the controls on carbon fluxes in a productive region impacted by upwelling, we measured biological productivity via multiple methods during a cruise in Monterey Bay, California. We quantified net community production and gross primary production from measurements of
/Ar and
triple isotopes (
), respectively. We simultaneously conducted incubations measuring the uptake of 14C,
, and
, and nitrification, and deployed sediment traps. At the start of the cruise (Phase 1) the carbon cycle was at steady state and the estimated net community production was 35(10) and 35(8) mmol C m−2 d−1 from
/Ar and 15N incubations, respectively, a remarkably good agreement. During Phase 1, net primary production was 96(27) mmol C m−2 d−1 from C uptake, and gross primary production was 209(17) mmol C m−2 d−1 from
. Later in the cruise (Phase 2), recently upwelled water with higher nutrient concentrations entered the study area, causing 14C and
uptake to increase substantially. Continuous
/Ar measurements revealed submesoscale variability in water mass structure and likely productivity in Phase 2 that was not evident from the incubations. These data demonstrate that
/Ar and
incubation‐based NCP estimates can give equivalent results in an N‐limited, coastal system, when the nonsteady state
fluxes are negligible or can be quantified.
Forecasting scintillation activity and equatorial spread F
Authors: Anderson David N. , Redmon Robert J.
Published: January 2017

When transionospheric radio waves propagate through an irregular ionosphere with plasma depletions or “bubbles,” they are subject to sporadic enhancement and fading, which is referred to as scintillation. Communication and navigation systems may be subject to these detrimental effects if the scintillation is strong enough. It is critical to have knowledge of the current ionospheric conditions so that system operators can distinguish between the natural radio environment and system‐induced failures. In this paper we briefly describe the Forecasting Ionospheric Real‐time Scintillation Tool UHF scintillation forecasting technique, which utilizes the observed characteristic parameter h′F from a ground‐based, ionospheric sounder near the magnetic equator. The prereversal enhancement in vertical E × B drift velocity after sunset is the prime driver for creating plasma depletions and bubbles. In addition, there exists a “threshold” in the h′F value at 1930 LT, h′Fthr, such that, on any given evening, if h′F is significantly above h′Fthr, then scintillation activity is likely to occur, and if it is below h′Fthr, scintillation activity is unlikely to occur. We use this technique to explain the lack of scintillation activity prior to the Halloween storm in October 2003 in the Peruvian longitude sector. In addition, we have carried out a study which forecasts the occurrence or nonoccurrence of equatorial spread F (ESF), on a night‐to‐night basis, in five longitude sectors. The overall forecasting success is greater than 80% for each of the five longitude sectors.
Subgrid parameterization for snow depth over mountainous terrain from flat field snow depth
Authors: Helbig N. , van Herwijnen A.
Published: January 2017

Snow depth is an important variable for a variety of models including land‐surface, meteorological, and climate models. Various measurement networks were therefore developed to measure snow depth on the ground. Measurement stations are generally located in gentle terrain (flat field measurements) most often at lower or mid elevation. While these sites have provided a wealth of information, various studies have questioned the representativity of such flat field measurements for the surrounding topography, especially in alpine regions. Using highly resolved snow depth maps at the peak of winter from two distinct climatic regions in Switzerland and in the Spanish Pyrenees, we developed two parameterizations to estimate domain‐averaged snow depth in coarse‐scale model applications over complex topography using easy to derive topographic parameters. The first parameterization uses a commonly applied linear lapse rate. Removing the dominant elevation gradient in mean snow depth revealed remaining underlying correlations with other topographic parameters, in particular the sky view factor. The second parameterization combines a power law elevation trend scaled with the subgrid parameterized sky view factor. Using a variety of statistic measures showed that the more complex parameterization performs better when using mean high‐resolution flat field snow depth. The performances slightly decreased when formulating the parameterizations for a single flat field snow depth measurement. Nevertheless, the more complex parameterization still outperformed the linear lapse rate model. As the parameterization was developed independently of a specific geographic region, we suggest it could be used to assimilate flat field snow depth or snowfall into coarse‐scale snow model frameworks.
Controlled Sub‐Micrometer Hierarchical Textures Engineered in Polymeric Fibers and Microchannels via Thermal Drawing
Authors: Nguyen‐Dang Tung , de Luca Alba C. , Yan Wei , Qu Yunpeng , Page Alexis G. , Volpi Marco , Das Gupta Tapajyoti , Lacour Stéphanie P. , Sorin Fabien
Published: January 2017

The controlled texturing of surfaces at the micro‐ and nanoscales is a powerful method for tailoring how materials interact with liquids, electromagnetic waves, or biological tissues. The increasing scientific and technological interest in advanced fibers and fabrics has triggered a strong motivation for leveraging the use of textures on fiber surfaces. Thus far however, fiber‐processing techniques have exhibited an inherent limitation due to the smoothing out of surface textures by polymer reflow, restricting achievable feature sizes. In this article, a theoretical framework is established from which a strategy is developed to reduce the surface tension of the textured polymer, thus drastically slowing down thermal reflow. With this approach the fabrication of potentially kilometers‐long polymer fibers with controlled hierarchical surface textures of unprecedented complexity and with feature sizes down to a few hundreds of nanometers is demonstrated, two orders of magnitude below current configurations. Using such fibers as molds, 3D microchannels are also fabricated with textured inner surfaces within soft polymers such as poly(dimethylsiloxane), at dimensions and a degree of simplicity impossible to reach with current techniques. This strategy for the texturing of high curvature surfaces opens novel opportunities in bioengineering, regenerative scaffolds, microfluidics, and smart textiles.
Iron‐Catalyzed Isopropylation of Electron‐Deficient Aryl and Heteroaryl Chlorides
Authors: Sanderson James N. , Dominey Andrew P. , Percy Jonathan M.
Published: January 2017

Traditional methods for the preparation of secondary alkyl‐substituted aryl and heteroaryl chlorides challenge both selectivity and functional group tolerance. This contribution describes the use of statistical design of experiments to develop an effective procedure for the preparation of isopropyl‐substituted (hetero)arenes with minimal isopropyl to n‐propyl isomerization. The reaction tolerates electronically diverse aryl chloride coupling partners, with excellent conversion observed for strongly electron‐deficient aromatic rings, such as esters and amides. Electron‐rich systems, including methyl‐ and methoxy‐substituted aryl chlorides, were found to be less reactive. Furthermore, the reaction was found to be most successful when heteroaryl chlorides were submitted to the cross‐coupling protocol. By mapping substituent effects on reaction selectivity, we were able to show that electron‐deficient aryl chlorides are essential for efficient coupling, and use electronic structure calculations to predict the likelihood of successful coupling through the estimation of the electron affinity of each aryl chloride. Moderate isolated yields were achieved with selected aryl chlorides, and moderate to good isolated yields were obtained for all the heteroaryl chlorides coupled. Excellent selectivity was observed when a 2,6‐dichloroquinoline was used, allowing mono‐substitution on a challenging substrate.

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Hydrogen separation at elevated temperatures using metallic nickel hollow fiber membranes
Authors: Wang Mingming , Song Jian , Li Yuan , Tan Xiaoyao , Chu Yuanyuan , Liu Shaomin
Published: January 2017

Nickel is a cheaper metallic material compared to palladium membranes for H2 separation. In this work, metallic Ni hollow fiber membranes were fabricated by a combined phase inversion and atmospheric sintering method. The morphology and membrane thickness of the hollow fibers was tuned by varying the spinning parameters like bore liquid flow rate and air gap distance. H2 permeation through the Ni hollow fibers with N2 as the sweep gas was measured under various operating conditions. A rigorous model considering temperature profiles was developed to fit the experimental data. The results show that the hydrogen permeation flux can be well described by using the Sieverts’ equation, implying that the membrane bulk diffusion is still the rate‐limiting step. The hydrogen separation rate in the Ni hollow fiber module can be improved by 4–8% when switching the co‐current flow to the countercurrent flow operation. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3026–3034, 2017
Bactericidal antibiotics promote oxidative damage and programmed cell death in sinonasal epithelial cells
Authors: Kohanski Michael A. , Tharakan Anuj , London Nyall R. , Lane Andrew P. , Ramanathan Murugappan
Published: January 2017

Background

Antibiotics are widely and heavily used in the treatment of chronic sinusitis. Bactericidal antibiotics can stimulate reactive oxygen species (ROS) formation, a proinflammatory response, and cell death in cultured human sinonasal epithelial cells (SNECs). Sulforaphane (SFN) is a potent stimulator of the antioxidant nuclear factor erythroid 2‐related factor 2 (Nrf‐2) system and a suppressor of inflammation. In this study we utilized SFN to further explore the relationship between levofloxacin treatment, ROS formation, and the cell death response.

Methods

SNECs were collected from patients during endoscopic sinus surgery and grown in culture at the air‐liquid interface. Differentiated SNECs were stimulated with levofloxacin with or without SFN pretreatment. ROS were quantified. Apoptosis markers of caspase‐3 activity and DNA fragmentation were quantified.

Results

Cultured SNECs treated with levofloxacin resulted in a significant increase in activity of the proapoptotic caspase‐3 protease (5.9‐fold, p = 0.01). The increase in activity was suppressed by pretreatment with SFN (1.9‐fold). ROS levels increased with levofloxacin treatment (range, 1.2‐fold to 1.8‐fold), but were not significantly suppressed by pretreatment with SFN (range, 1.0‐fold to 1.3‐fold).

Conclusion

In this study, we demonstrate that treatment of cultured SNECs with levofloxacin leads to an increase in caspase‐3 activity. SFN pretreatment suppresses the increased apoptotic response possibly through its antioxidant stimulating properties. Our results suggest that levofloxacin treatment stimulates a potent proapoptotic possibly through an ROS‐dependent mechanism. Future studies will explore if this antibiotic‐induced response is harmful to recovery of function in those with sinusitis.
In situ synthesis of metallophthalocyanines into pores of MIL‐101: A novel and green strategy for preparation of host–guest catalysts
Authors: Boroujeni Mahmoud Borjian , Hashemzadeh Alireza , Shaabani Ahmad , Amini Mostafa M.
Published: January 2017

A novel strategy is developed to encapsulate metallophthalocyanines (MPcs, M = Cu, Ni and Co) into MIL‐101 to give MPcs@MIL‐101 via in situ synthesis of MPcs from component fragments in 1‐butyl‐3‐methylimidazolium bromide as an ionic liquid. This strategy overcomes some drawbacks of existing methods for encapsulation of MPcs into metal–organic frameworks. The chemical and structural properties of MPcs@MIL‐101 were determined using scanning electron microscopy, powder X‐ray diffraction, and Fourier transformation infrared and flame atomic absorption spectroscopies. The results showed that CuPc@MIL‐101, which was used as a ‘ship‐in‐a‐bottle’ catalyst, demonstrates excellent catalytic performance in the oxidative amidation of aldehydes with amine salts. It is confirmed that CuPc@MIL‐101 can be reused up to five times without significant loss of its activity.
Viscoelastic rheology in the melting and crystallization domain: Application to polypropylene copolymers
Authors: Aris‐Brosou Margaux , Vincent Michel , Agassant Jean‐François , Billon Noëlle
Published: January 2017

The purpose of this article was to study the relationship between the rheological properties and the crystallization or melting of two polypropylene‐based copolymers used in the welding of the coating of offshore pipelines. The materials microstructure was studied via X‐ray diffraction, scanning electron microscopy, and optical microscopy. Differential scanning calorimetry was used to determine the crystallization and melting properties at different cooling and heating rates. Dynamic rheological analysis was used to define the rheological properties in the molten and in the transition zone from the molten to solid state and inversely. Both experiments (DSC and rheology) were performed under non‐isothermal conditions to allow complete accessibility to the transition zone. Crystallization and melting are both complex processes in which coexist amorphous and crystalline phases in the sample. A correlation between the rheological properties and crystallization was proposed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44690.
A traditional aboriginal condiment as an antioxidant agent in the development of biodegradable active packaging
Authors: López de Dicastillo Carol , Bruna Julio , Torres Alejandra , Alvarado Nancy , Guarda Abel , Galotto María José
Published: January 2017

In this study, antioxidant food‐packaging materials were developed by the incorporation of merkén, an aboriginal Chilean spice, into a biodegradable polymer matrix, poly(lactic acid). Antioxidant activity assays and the phenolic content of merkén showed interesting results compared to other condiments, such as oregano and parsley. Active materials with merkén at 3 and 5 wt % were successfully obtained by extrusion. Chromatographic analysis revealed the chemical composition of merkén, and its active material was based on interesting flavonoids and organic acids, such as catechin, myricetin, and gallic and ellagic acids. Scanning electron micrographs showed that the merkén particles accumulated in aggregates; this resulted in an increase in the permeability values and a reduction in the crystallinity and mechanical properties of the polymer matrix. Nevertheless, these materials presented interesting antioxidant activities as radical scavengers on aqueous food simulants. The kinetics of release was dependent on the type of food and the nominal content of merkén in the films. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44692.
Photochemistry of 2,6‐di(4′‐azidobenzylidene)‐methylcyclohexanone in polymer matrices
Authors: Avadanei Mihaela
Published: January 2017

2,6‐Di(4′‐azidobenzylidene)‐methylcyclohexanone (ABC) was one of the most used photoinitiators in negative photoresists industry, rendering insolubility of the resist films at short UV exposure times (several minutes). Although the photodecomposition of aromatic azides is very well established, the peculiarities of the irradiation medium impose specific reaction pathways for arylnitrenes. In this study, photoreactions of arylnitrenes resulted from ABC photolysis were applied in the photoinitiated crosslinking of 1,2‐polybutadiene (1,2‐PB), under soft monochromatic UV irradiation (365 nm). To elucidate the crosslinking mechanism, studies on a model compound were performed. 3‐Methyl‐1‐butene was chosen to simulate the monomeric unit of 1,2‐PB. As a support in photoproducts identifying and with the purpose of a deeper investigation of the ABC photochemistry alone, ABC was photolysed in a rigid matrix of poly(methyl methacrylate). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44694.
Antioxidation and mechanism of phosphites including the free phenolic hydroxyl group in polypropylene
Authors: Meng Xin , Jiang Zewen , Xin Zhong , Chen Weijie , Sheng Yan , Wu Chushi
Published: January 2017

Inhibiting the degradation of polypropylene (PP) in melt processing and usage is an important issue in the plastic industry. It is becoming more and more urgent to increase the antioxidation of phosphites alone while maintaining the water resistance. In this study, one phosphite antioxidant, named bis‐2,2′‐methyl‐4,6‐di‐tert‐butylphenyl phosphite (BM46TBPP), which contains a water‐resistant inner ring and a free phenolic hydroxyl group together, was synthesized. Then, antioxidation in PP was characterized with multiple extrusions and oxidation induction times (OITs). Finally, the hydrogen‐donating ability of this antioxidant was tested with 2,2‐diphenyl‐1‐picrylhydrazyl radical colorimetry to explain the antioxidation mechanism. The results show that the phosphite BM46TBPP displays better antioxidation than tris(2,4‐di‐tert‐butylphenyl) phosphite (Irgafos 168) in melt processing and OIT testing. Furthermore, the priority of this antioxidant was more obvious when it was used in the presence of oxygen, so the antioxidant even made the PP stabilized by it alone show a longer OIT value than the PP stabilized by the complex system including Irgafos 168 and 2,4‐di‐tert‐butylphenol because there was a free phenolic hydroxyl group in the BM46TBPP antioxidant molecule and the hydroxyl group made the antioxidant show intermolecular synergistic antioxidation through hydrogen donation to radicals. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44696.
Correlation of the polymer hydrophilicity and membrane fabrication process on the properties of asymmetric membranes in a vapor‐induced phase‐inversion process
Authors: Zhu Jianhua , Zhang Qifeng , Zheng Jifu , Hou Shuhua , Zhang Suobo , Li Shenghai
Published: January 2017

In this study, we sought a better understanding of how the hydrophilicity of a polymer affects the morphology and performance of membranes. Three types of polymer with different hydrophilicity solution systems were considered: poly(aryl ether ketone) bearing a hydroxyl group (PEK–OH‐100) with N,N‐dimethylformamide (DMF); poly(aryl ether ketone) bearing a 50% fraction hydroxyl group with DMF, and cardo poly(aryl ether ketone) with DMF. These systems were used to investigate the evolution of the morphology and variation in performance versus a change in the hydrophilicity of the polymer. In addition, the fundamental thermodynamic influence of the solution systems on the phase‐inversion process was investigated by cloud‐point measurement and Hansen solubility parameter theory to determine the role of polymer hydrophilicity on the stability of the polymer solution in humid surroundings. The performance of the membranes was tested via testing of the pure water flux, porosity, and rejection of bovine serum albumin (BSA) with respect to variations in the polymer hydrophilicity, evaporation time, relative humidity, and molecular weight of the polymer. The resulting optimal membrane exhibited a flux of 329.3 L m−2 h−1 and a 99.3% rejection of BSA at a relative humidity of 90% and an evaporation time of 3 s. The hydrophilic PEK–OH‐100 membranes have promising applications in protein separation and the porous support of reverse‐osmosis membranes and so on. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44701.
The toughening behavior of PLLA and its asymmetric PLLA/PDLA blends with lower optical purity
Authors: Guo Yanmei , Shao Jun , Hou Haoqing
Published: January 2017

Linear poly(d‐lactide) (PDLA) with various molecular weights is synthesized and incorporated into commercial poly(l‐lactide) (PLLA) with different optical purities. And then, the crystallization, mechanical and thermal properties of the PLLA and PLLA/PDLA cast films are investigated. In the PLLA and PDLA/PLLA specimens with lower optical purity, few homochiral crystallites (HC) form in all the specimens and only a small amount of PLA stereocomplex crystallites (SC) are observed in the blends. The elongation at break of all the specimens is extraordinary high, >300%. Dynamic mechanical analyses indicate that the destruction temperature increases at first, and then depresses as enlarging the molecular weight of PDLA in these blends. For the PLLA and PLLA/PDLA with higher optical purity, more content of HC develops in neat PLLA, and both SC and HC produce in the PLLA/PDLA specimens. However, the strains of neat specimens and binary blends are much lower than that of specimens with lower optical purity. The specimens with higher optical purity exhibit higher destruction temperatures and lower loss factors. The high content of crystals (SC and HC) would act as the physical cross‐linking points and provide a key factor to impede the deformation of neat PLLA and binary blends during stretching, which should result in the fragile behavior of the PLLA and PLLA/PDLA blends with higher optical purity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44730.
Elaboration of performance of tea dust–polypropylene composites
Authors: Rathod Yogita , Bari Pravin , Hansora D. P. , Mishra Satyendra
Published: January 2017

In this research work, dynamic, mechanical, and thermophysical properties of untreated and 5, 7, and 10 wt % styrene treated tea dust (TD):polypropylene (PP) composites prepared by injection‐molding machine were elaborated. There were distinctive and significant improvement observed in mechanical properties (tensile strength, tensile modulus, and elongation at break), physical analysis (water swelling), dynamic mechanical properties (storage modulus, loss modulus, and tan δ), and thermal behavior and surface morphological properties of styrene treated TD:PP (40:60) composites as compared to that of untreated one. The tensile strength (from 7.00 to 9.95 MPa), tensile modulus (from 350 to 715 MPa), storage modulus (from 8500 to ∼10,500 MPa), and loss modulus (from ∼150 to ∼200 MPa) increased on 10 wt % styrene treatment of TD over the untreated TD:PP (40:60) composites. The styrene treated TD:PP (40:60) composites behaved as more elastic than their pure counterpart. Styrene treated TD:PP (40:60) composites were more thermally more stable (85 °C difference) as compared to virgin PP. Overall, this research also indicates the use of TD waste. An improvement in dispersion of styrene treated TD particles in PP was also observed in the preparation of the PP composites due to good compatibility of styrene with PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44750.
Removal of Cd2+ ions from aqueous solution using cassava starch–based superabsorbent polymers
Authors: Bai Wenbo , Fan Liren , Zhou Yang , Zhang Yin , Shi Jiyan , Lv Guohua , Wu Yongfeng , Liu Qi , Song Jiqing
Published: January 2017

A comprehensive feasibility study on the adsorption of Cd2+ ions by cassava starch–based superabsorbent polymers (CST‐SAPs) as the biosorbent was investigated as a function of adsorbent dosage, pH, initial concentration, contact time, and temperature. An orthogonal experiment and range analysis were applied to optimize the adsorption conditions. Adsorbent dosage and initial concentration were the most sensitive variables for adsorption capacity. The maximum adsorption value of Cd2+ ions was determined as 347.46 mg/g at pH 6.0, initial concentration of 200 mg/L, and contact temperature and time of 323 K and 6 h, respectively, with 0.1 g adsorbent dosage. The equilibrium data were well described by a Langmuir model, and the adsorption process was well fitted by pseudo‐second‐order kinetics. The Fourier transform infrared spectroscopy (FTIR) data confirmed that acrylic acid and acrylic amide grafted onto the cassava starch. The X‐ray diffraction and FTIR results for the Cd2+‐absorbed CST‐SAP (CST‐SAP‐Cd2+) samples showed that the CST‐SAP could effectively adsorb Cd2+ ions and that the characteristic groups were translocated by chelation. The scanning electron microscopy results for the CST‐SAP revealed that the surface of the polymer was rough, and the layered structure that was full of folds caused an enhanced specific surface; such conditions were beneficial to Cd2+ ion adsorption. It was concluded that the CST‐SAP was an excellent adsorbent for Cd2+ ion removal from aqueous solution. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44758.