bluuebunny/crossref_metadata_2025 huggingface dataset:
Aesthetics and symbolic meaning of ancient Chinese snowy landscapes from the IV to the XX century.
Authors: CHANG RUI
Published: May 2024

The article examines the aesthetic and symbolic aspects of ancient Chinese snowy landscapes, covering the period from the IV to the XX century. The focus of the research is Guohua painting, representing classic snowy landscapes, compositions with birds and flowers, as well as snow portraits. An in-depth analysis of the symbolism and meaning of elements such as "four seasons", "snow", "snowy mountains", "three friends of cold time" and "cold beasts" was carried out, as well as the narrative characteristics of snowy landscapes were studied. It was revealed that snow scenes reflect the vitality and stability of a person, causing reflections on life difficulties. The work highlights how snowy landscapes have become a means of expressing emotions, reflecting sadness, but also demonstrating strength, well-being, morality and the sublimity of cultural values. The study uses the methodology of symbolism and iconology analysis to study the aesthetics of ancient Chinese snowy landscapes. A comparative approach is applied to various eras and techniques, including ink painting and engraving, to assess the cultural and emotional meanings of snow in Chinese art. The research touches on a rarely covered topic in the history of art – the aesthetic and symbolic depth of ancient Chinese snowy landscapes, from the IV to the XX century. Introducing into scientific discourse a deep analysis of changes in the perception and image of snow, the work presents a comprehensive study using iconology and semiotics to uncover hidden meanings in Chinese Guohua painting. She reveals how artists have reflected the emotional and philosophical aspects of life through snowy landscapes, demonstrating their influence on cultural representations of nature, man and society. The innovation of the study lies in the fact that it connects the aesthetic elements of snow with cultural and historical changes in China, showing their importance for understanding Chinese identity and aesthetic perception. This study not only enriches the academic understanding of Chinese painting, but also highlights the layering of symbols and metaphors in traditional art, reflecting a unique combination of natural phenomena and cultural meanings.
Screening and identification of heat tolerance in Indian wheat genotypes using generalized regression neural network (GRNN) model
Authors: Kumar Anil , Fatima Sadaf , Azim Iffat , Negi Anshika , Bhadola Shalini , Jha Pooja , Hairat Suboot
Published: May 2024

The present study using a generalized regression neural network (GRNN) model was carried out to check the effect of high temperature on five Indian bread wheat genotypes, namely, C306, K7903, CBW12, HD2329, and HD2428, and to develop an algorithm for the screening and identification of heat tolerance in wheat. A highly significant differential survivability in response to the temperature induction response technique with germinating seeds was observed for the five wheat genotypes. Maximum survivability was observed for C306 and K7903, whereas HD2329 and HD2428 showed minimum survival in response to lethal temperature stress. Similarly, at the mature plant stage, in response to heat treatment of 34°C/26°C (day/night), all five wheat genotypes showed a significant difference in chlorophyll a fluorescence, total chlorophyll content, and the reduction of 1,1- diphenyl-2-picryl-hydrazyl (DPPH) in response to heat treatment. The genotypes, C306, K7903, and CBW12 showed better performance for all the chlorophyll a fluorescence parameters under study including Fo, Fv/Fm, qL, qP, NPQ, θPSII, ETR, along with the total chlorophyll content and DPPH reduction, in contrast, the genotypes, HD2329 and HD2428 performed poorly for all parameters including chlorophyll a fluorescence parameters, total chlorophyll, and DPPH reduction. Higher inflection temperature and peak temperature were observed in C306 and K7903, in contrast, HD2329 and HD2428 showed significantly lower inflection temperature and peak temperature. Higher expression of the selected genes involved in photosynthesis and ROS scavenging was observed in C306 and K7903 relative to HD2329 and HD2428. On the basis of the different chlorophyll a fluorescence parameters, the algorithm was developed for the calculation of the heat susceptibility index. The algorithm was independently checked for the identification and segregation of all the five wheat genotypes taken in this study as tolerant, moderate, and susceptible. For all the genotypes, the algorithm was able to predict the heat susceptibility of the genotypes with high accuracy. Hence, the algorithm in combination with chlorophyll a fluorescence can be used for the screening of wheat and other plant species in response to abiotic stress, especially heat stress.
Application of two-level factorial design in optimization of maceration extraction of Curcuma longa curcuminoids extracts
Authors: Heryanto Rudi , Sa’diah Siti , Nurcholis Waras
Published: May 2024

A two-level factorial design was used to identify extraction factors that could improve Curcuma longa rhizome extraction yield (EY) and curcuminoid content (CC). These extraction factors included solid/liquid ratio (A: 0.10– 0.20 g/mL), ethanol concentration (B: 50–70%), and time maceration (C: 3–6 h). Under the prevailing circumstances, the yield of extract and CC varied from 2.86% to 20.90% and from 1.80% to 21.59%, respectively. The findings indicated that all three parameters were statistically significant (P < 0.05) in contributing to increase EY. The increase in CC was significantly influenced by ethanol concentration alone. Therefore, these findings suggest that adjusting the solid/liquid ratio, ethanol concentration, and maceration time can enhance the efficiency of curcuminoid extraction from C. longa rhizomes.
Cholecystokinin facilitates motor skill learning by modulating neuroplasticity in the motor cortex
Authors: Li Hao , Feng Jingyu , Chen Mengying , Xin Min , Chen Xi , Liu Wenhao , Wang Liping , Wang Kuan Hong , He Jufang
Published: May 2024

Cholecystokinin (CCK) is an essential modulator for neuroplasticity in sensory and emotional domains. Here, we investigated the role of CCK in motor learning using a single pellet reaching task in mice. Mice with a knockout of Cck gene (Cck−/−) or blockade of CCK-B receptor (CCKBR) showed defective motor learning ability; the success rate of retrieving reward remained at the baseline level compared to the wildtype mice with significantly increased success rate. We observed no long-term potentiation upon high-frequency stimulation in the motor cortex of Cck−/− mice, indicating a possible association between motor learning deficiency and neuroplasticity in the motor cortex. In vivo calcium imaging demonstrated that the deficiency of CCK signaling disrupted the refinement of population neuronal activity in the motor cortex during motor skill training. Anatomical tracing revealed direct projections from CCK-expressing neurons in the rhinal cortex to the motor cortex. Inactivation of the CCK neurons in the rhinal cortex that project to the motor cortex bilaterally using chemogenetic methods significantly suppressed motor learning, and intraperitoneal application of CCK4, a tetrapeptide CCK agonist, rescued the motor learning deficits of Cck−/− mice. In summary, our results suggest that CCK, which could be provided from the rhinal cortex, may surpport motor skill learning by modulating neuroplasticity in the motor cortex.
Binding of LncRNA-DACH1 to dystrophin impairs the membrane trafficking of Nav1.5 protein and increases ventricular arrhythmia susceptibility
Authors: Pan Zhenwei , Xue Gen-Long , Yang Jiming , Zhang Yang , Yang Ying , Zhang Ruixin , Li Desheng , Tian Tao , Zhang Xiaofang , Li Changzhu , Li Xingda , Yang Jiqin , Shen Kewei , Guo Yang , Liu Xuening , Yang Guohui , Lu Yanjie , Yang Baofeng
Published: May 2024

Dystrophin is a critical interacting protein of Nav1.5 that determines its membrane anchoring in cardiomyocytes. Long noncoding RNAs (lncRNAs) are involved in the regulation of cardiac ion channels, while their influence on sodium channel remains unexplored. Our preliminary data showed that lncRNA-Dachshund homolog 1 (lncDACH1) can bind to dystrophin, which drove us to investigate if lncDACH1 can regulate sodium channel by interfering with dystrophin. Western blot and immunofluorescent staining showed that cardiomyocyte-specific transgenic overexpression of lncDACH1(lncDACH1-TG) reduced the membrane distribution of dystrophin and Nav1.5 in cardiomyocytes. Meanwhile, peak
I
Na
were reduced in the hearts of lncDACH1-TG mice than wild-type (WT) controls. The opposite data of western blot, immunofluorescent staining and patch clamp were collected from lncDACH1 cardiomyocyte conditional knockout (lncDACH1-cKO) mice. Moreover, increased ventricular arrhythmia susceptibility was observed in lncDACH1-TG mice
in vivo
and
ex vivo
. The conservative fragment of lncDACH1 inhibited membrane distribution of dystrophin and Nav1.5, and promoted the inducibility of ventricular arrhythmia. Strikingly, activation of dystrophin transcription by dCas9-SAM system in lncDACH1-TG mice rescued the impaired membrane distribution of dystrophin and Nav1.5, and prevented the occurrence of ventricular arrhythmia. Furthermore, lncDACH1 was increased in transaortic constriction (TAC) induced failing hearts, which promoted the inducibility of ventricular arrhythmia. And the expression of lncDACH1 is regulated by hydroxyacyl-CoA dehydrogenase subunit beta (hadhb), which binds to lncDACH1 and decreases its stability. The human homologue of lncDACH1 inhibited the membrane distribution of Nav1.5 in human iPS-differentiated cardiomyocytes. The findings provide novel insights into the mechanism of Nav1.5 membrane targeting and the development of ventricular arrhythmias.
Improving the Uniform Distribution of Water Flux Density in Sprinkler Spray by Adopting Various Installation Methods
Authors: Song Jae-Keum , Kim Taehoon
Published: May 2024

In a sprinkler system, the nonuniform water flux distribution resulting from the sprinkler head design, specifically due to the deflector and frame, impedes the primary extinguishing surface cooling effect of the sprinkler. In this study, the effects of the distance between heads, supplying flow rate, head installation direction, and head installation height on the uniformity of the water flux density distribution were investigated. Simulations were conducted using the water flux distribution reproduction method proposed in a previous study. As the distance between heads decreased, water was supplied to the bottom of the head, resulting in the improved uniformity of the water flux distribution. When the flow rate was corrected with the changes in the distance between the heads to maintain the average water flux density supplied to the floor, a uniform water flux distribution was observed even when the distance between heads was relatively large. In the case of head installation direction, the most uniform distribution was observed when the sprinkler heads were installed alternately at angles corresponding to 0° and 135°. As the installation height of the sprinkler heads increased, the difference between the maximum and minimum local water flux densities decreased, leading to a more uniform water flux density distribution.
Initial Fire Detection Method for Intelligent CCTV Using Deep Learning Technology
Authors: Kang Kyeong-Sin , Kwon Oh-Sung , Cho Wan-Ho , Kim Heung-Youl , Chae Seung-Un , You Ji-Sun
Published: May 2024

Pre-prediction and early detection are important for the prevention of fires. Hence, the integration of intelligent CCTV image analysis technology, deep learning, and artificial intelligence is actively being studied. Intelligent CCTV can analyze visible light images of fires, but the accuracies of the detection targets are low. To solve this problem, a dual sensing experimental device was constructed by combining a visible light sensor and a thermal image sensor, and an algorithm was implemented to predict fire events. An algorithm was constructed to detect three classes (Fire, Smoke, and Person) through RGB sensors and thermal imaging sensors. Additionally, a CNN deep learning method and the YOLOv5 method were used to build a classification neural network. The dual sensing device was able to act as a trigger to predict and detect a fire based on the size of the flame and changes in temperature.
ESTRÉS ACADÉMICO EN ESTUDIANTES DE LICENCIATURA EN MEDICINA DE UNA UNIVERSIDAD PÚBLICA DE QUERÉTARO, MÉXICO
Authors: González Briones José Manuel , Ferrusca Rangel Lizbeth Gabriela , Ortiz Reséndiz Andrés , Gallegos Torres Ruth Magdalena , Juárez Nilo Sarket Gizeh
Published: May 2024

INTRODUCCIÓN. El estrés académico es un fenómeno que se encuentra presente a diario en la vida de cualquier estudiante, sobre todo universitario. Se reconoce que la carrera de medicina es una presión altamente demandante, por lo que los alumnos son altamente susceptibles a situaciones de estrés elevado. OBJETIVO. Determinar el nivel de estrés académico que existe en los estudiantes de la Licenciatura en Medicina de la Universidad Autónoma de Querétaro (México), en el 2022. METODOLOGÍA. Estudio cuantitativo, transversal descriptivo, en el cual se tomó una muestra no probabilística de 132 estudiantes a partir del tercer semestre de la carrera, todos residentes del estado de Querétaro, hombres y mujeres. Se aplicó el inventario SISCO- SV21 para recolección de datos, con un Alfa de Cronbach de 0,85. Se determinaron frecuencias y promedios de los datos mediante el programa SPSS v.25. RESULTADOS. El 60% de los estudiantes percibe tener un alto nivel de estrés. El 50% manifiesta tener fatiga crónica y 46% desgano. El 50% se estresa por los tiempos limitados para la entrega de trabajos. La principal estrategia de afrontamiento utilizada fue el establecer soluciones concretas a los problemas, con un 48,1%. CONCLUSIONES. Existe una necesidad inminente en la creación de programas para el mantenimiento de la salud mental de los futuros profesionales de la medicina, ya que el estrés académico es una barrera que le permite al estudiante desarrollarse de manera integral en su formación.
Comparison of Removal of Laryngeal Mask Airway in Deeply Anaesthetised and Awake Paediatric Patients and their Associated Complications: A Randomised Clinical Study
Authors: Chhikara Monica , Seelwal Deepika
Published: May 2024

Introduction: The Laryngeal Mask Airway (LMA) is frequently used for managing paediatric airways for short surgical procedures. While it is easy to insert, it can lead to several complications if not removed at the appropriate plane of anaesthesia. Aim: To establish better timing for the removal of the LMA in deeply anaesthetised and awake paediatric patients by comparing the complications associated with each approach. Materials and Methods: The present randomised clinical study, enrolled 90 American Society of Anaesthesiologists (ASA) I and II paediatric patients aged 1 to 12 years, posted for elective short surgical procedures under general anaesthesia with airway management by Classical LMA. The patients were allocated into two groups: Group D (LMA removal under a deep plane/surgical plane of anaesthesia) and Group A (LMA removal in a fully awake state). At emergence from anaesthesia and during LMA removal, both groups were studied for complications including cough, desaturation (SpO2 < 95%), excessive salivation, vomiting, and laryngospasm. Descriptive statistics were reported using mean±standard deviation or median (range) for continuous variables. Comparison of continuous variables was done using the Student’s t-test or Wilcoxon rank sum test. Results: Demographic data like age, weight, duration of surgery, heart rate, and respiratory rate were comparable in both groups. A significantly higher incidence of cough was found in group A compared to group D (p-value=0.001). The incidences of desaturation (p-value=1.000), excessive salivation (p-value=0.361), vomiting (p-value=1.000), and laryngospasm (p-value=0.142) were comparable between the two groups. Cough was the most frequent complication in group A (16 out of 45 patients), while laryngospasm was the most frequent complication in group D (8 out of 45 patients). The total number of complications (p-value=0.043) was significantly higher in group A compared to group D. Conclusion: The removal of the Classical LMA in paediatric patients can be safely carried out in a deeply anaesthetised state. Based on the results of present study, the removal of the LMA in deeply anaesthetised paediatric patients is associated with fewer complications compared to its removal in the awake state.
A Comprehensive Review of Synthesis, Properties and Applications of TiO2 and ZnO Nanoparticles
Authors: Joseph Suja , Nallaswamy Deepak , Rajeshkumar Shanmugam , Dathan Pradeep , Jose Leon
Published: May 2024

Nanotechnology is an advancing field of science with the potential to improve the quality of life through its applications in the field of nanomedicine. It refers to the technology of precisely manipulating atoms and molecules and developing new materials with nanoscale dimensions. Nanoparticles (NPs) typically range in size from 1-100 nm. Nanoparticles play a major role in the prevention of infections, so they can be utilised as nanocarriers with antimicrobial therapeutic actions. This article is a literature review on different methods of synthesis, properties, and biomedical applications of Titanium Dioxide (TiO2 ) and Zinc oxide (ZnO) nanoparticles. Since nanoparticles can be biomodified by cost-effective methods, the use and applications of NPs will increase in the future. The unique properties of nanoparticles make them useful in various fields of science such as materials, engineering, electronics, food science, and biomedicine. Due to their advantages, nanotechnology has gained the attention of researchers, especially for its promising applications in the healthcare system for better diagnosis and treatment.
Navigating the Portfolio Landscape: Examining Lecturers’ and Students’ Perspectives on Portfolio Assessment Practices
Authors: Apeadido Shine , Dzomeku Daniel , Nanor Emmanuel
Published: May 2024

This study examined the perceptions of lecturers and students regarding portfolio assessment practices, their overall attitudes towards this assessment method, and the alignment and divergence between their perceptions. Employing a survey research design, the study was conducted at the University of Education, Winneba, in the Central Region of Ghana, involving 52 final-year science education students and five of their lecturers. Students were selected using stratified random sampling, while lecturers were chosen purposefully. Data collection instruments comprised five-point Likert scale questionnaires administered to both groups, ranging from strongly disagree to strongly agree. Descriptive analysis, including mean, frequencies, and percentages, was utilised for data analysis. Results indicated that lecturers generally perceive a clear purpose for portfolio assessment practices (mean score = 4.20) and emphasise integrating them into every educational programme (mean score = 4.40), while students express lower levels of satisfaction with these aspects (mean scores = 2.15, 2.42, respectively). Additionally, lecturers exhibit moderate attitudes towards portfolio assessment (60.0%), while students predominantly demonstrate low attitudes (59.6%). Alignment between lecturers and students is evident in some areas, such as the importance of communicating objectives and providing feedback to students and the importance of this assessment in diagnosing students’ strengths and weaknesses, but discrepancies arise regarding the guidance of students during the practices. The study concluded that understanding and addressing the differences in perceptions and attitudes between lecturers and students is crucial for promoting a shared understanding and acceptance of portfolio assessment practices. In order to close gaps and foster meaningful engagement, it is then recommended that institutions prioritise efforts to improve communication, collaboration, and support for both lecturers and students to enhance the effectiveness of portfolio assessment practices in higher education.
PENGARUH PANDEMI TERHADAP PROFITABILITAS PERUSAHAAN BAJA
Authors: Febe Yobella , Budiman Januar
Published: May 2024

Pandemi Covid-19 tidak hanya berdampak pada kesehatan masyarakat, tetapi juga mempengaruhi kondisi perekonomian negara. Pandemi ini menyebabkan pemerintah menerapkan kebijakan pembatasan sosial. Kementerian Ketenagakerjaan, 2020, mengemukakan, sekitar 88% perusahaan yang terdampak pandemi pada umumnya dalam keadaan merugi. Kerugian tersebut umumnya disebabkan penjualan menurun, sehingga produksi harus dikurangi. Penelitian ini bertujuan untuk mengetahui profitabilitas perusahaan baja sebelum pandemi dan setelah pandemi yaitu pada tahun 2016 sampai 2020. Penelitian dilakukan pada perusahaan yang menjual-belikan sahamnya di Bursa Efek Indonesia dan memiliki laporan keuangan terlengkap selama tahun 2016 sampai 2020. Perusahaan yang akan diteliti adalah Krakatau Steel (KRAS), PT. Saranacentral Bajatama Tbk (BAJA), PT Gunawan Dianjaya Steel Tbk (GDST), PT Steel Pipe Industry of Indonesia Tbk (ISSP), dan PT Prima Alloy Steel Universal Tbk (PRAS).
Öğretmen Adaylarının Aile Katılımına Yönelik Tutumlarının Yordanmasında Karanlık Dörtlü Kişilik Özelliklerinin ve Algılanan Empatik ve Sosyal Öz-Yeterliğin Rolü
Authors: Türkdoğan Saniye Can , Balkıs Murat
Published: May 2024

Bu araştırmanın amacı, öğretmen adaylarının aile katılımına yönelik tutumlarının yordanmasında karanlık dörtlü kişilik özelliklerinin ve algılanan empatik ve sosyal öz-yeterlik düzeyinin rolünü incelemektir. Çalışma kapsamında, 416 öğretmen adayından gönüllülük esasına dayalı olarak veri toplanmıştır. Çoklu hiyerarşik regresyon analizinin ilk aşamasında, öğretmen adaylarının sahip olduğu sosyodemografik özellikler (cinsiyet, sınıf düzeyi, gelir düzeyi) kontrol değişkeni olarak tanımlanmış, ikinci aşamada öğretmen adaylarının karanlık dörtlü kişilik özellikleri (makyavelizm, narsisizm, psikopati ve sadizm) ve üçüncü aşamada empatik öz-yeterlik ve sosyal öz-yeterlik değişkenleri regresyon denklemine dâhil edilmiştir. Üç aşamalı hiyerarşik regresyon analizinin sonucunda, öğretmen adaylarının aile katılımına yönelik tutumlarının anlamlı yordayıcıları sadizm, psikopati ve sosyal öz-yeterlik değişkenleri olmuş, bu üç değişken aile katılımına yönelik tutumları orta düzeyde bir etki büyüklüğüyle açıklamıştır. Bulgular öğretmen adaylarının eğitiminde uyumlu kişilik özelliklerinin ve sosyal becerilerin desteklenmesinin önemine işaret etmektedir.
Mechanistische Einblicke in die Bindung und Aktivierung von N2O an Übergangsmetallzentren
Authors: Tolman William B.
Published: January 2010

Da Distickstoffoxid eine bedeutende Rolle beim Ozonabbau in der Stratosphäre und als Treibhausgas spielt, besteht ein großes Interesse daran, seinen Abbau insbesondere durch Metallpromotoren zu verstehen und effizienter zu machen. Neue Erkenntnisse über die Reaktionspfade bei der N2O‐Reduktion durch Metallionen in der Gasphase sowie in heterogenen, homogenen und biologischen Katalysesystemen haben interessante Einblicke in die Struktur und Eigenschaften von Metall‐N2O‐Addukten und abgeleiteten Intermediaten gegeben. Dieses vertiefte Verständnis wird sicher zur Entwicklung von wirksameren Katalysatoren für die Verringerung der N2O‐Emissionen beitragen.
Poly(ethylene‐2,6‐naphthalate) nanofiber prepared by carbon dioxide laser supersonic drawing
Authors: Suzuki Akihiro , Yamada Yuuki
Published: January 2010

Poly(ethylene‐2,6‐naphthalate) (PEN) nanofiber was prepared by a carbon dioxide (CO2) laser supersonic drawing. The CO2 laser supersonic drawing was carried out by irradiating the laser to the as‐spun PEN fiber in a low‐temperature supersonic jet. The supersonic jet was generated by blowing off air into a vacuum chamber from a fiber supplying orifice. The flow velocity from the orifice can be estimated by applying Graham's theorem from the pressure difference between the atmospheric pressure and the pressure of the vacuum chamber. The fastest flow velocity estimated was 396 m s−1 (Mach 1.15) at a chamber pressure of 6 KPa. The nanofiber obtained at Mach 1.15 was the oriented nanofibers with an average diameter of 0.259 μm, and its draw ratio estimated from the diameters before and after the drawing reached 430,822 times. The CO2 laser supersonic drawing is a new method to make nanofiber without using any solvent or removing the second component. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Application of Mie light scattering to the morphological development of polypropylene/polystyrene blends. I. Method for the determination of Mie scattering
Authors: Li Yun Yan , Yan Da , Ma Gui Qiu , Yuan Xu Bo , Sheng Jing
Published: January 2010

In this article, we introduce a new method, Mie scattering, for investigating the dependence of the morphology of polypropylene (PP)/polystyrene (PS) blends on the composition and mixing time. The size and corresponding distribution of the particles were also deduced on the basis of the Mie scattering theory. To confirm the effectiveness of this new method for morphology studies, scanning electron microscopy (SEM) was employed to study the morphology development as a function of the blend composition and mixing time; furthermore, the results by Mie scattering were compared with those by SEM analysis. The results by Mie scattering were similar to those by SEM, and this indicated that Mie scattering is an effective method for describing the morphology development of polymer blends. The main purpose of this article is simply to report this new method; in another article of this series, the application of this method in investigations of the compatibilization of PP/PS blends will be reported. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Artificial and natural weathering of ABS
Authors: Santos R. M. , Botelho G. L. , Machado A. V.
Published: January 2010

Acrylonitrile‐butadiene‐styrene (ABS) is a complex copolymer with exceptional importance in technological applications. However, ABS is known to present a high susceptibility to weathering when exposed to UV radiation in the presence of oxygen. In this work, photodegradation of ABS was studied under natural and accelerated conditions. Exposed samples were removed periodically and characterized by several analytical techniques. During both types of weathering chemical modifications occurs mainly at the surface, which affects considerable the optical, mechanical, and rheological properties. The results obtained evidence that during accelerated weathering the formation rate of photodegradation products is higher when compared to natural weathering results. However, chain scission occurs mainly along natural conditions. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effect of hydrolytic and thermal degradation on mechanical properties of industrial polyester yarns
Authors: Sheikhzadeh M. , Ghaeli I. , Pirzadeh E. , Bateni F.
Published: January 2010

For industrial polyester yarns, the study of hydrolytic/thermal degradation is important, because of the negative influence of these degradations on mechanical properties of polyester yarns. In this research, tensile force at breaking point and elongation at break were used to assess the hydrolytic and thermal degradation of industrial polyester yarns with two draw ratios of 3.5 and 4, which were exposed in water and in oven for 28 days and at different temperatures of Tg, below and above Tg. Totally, the amount of these degradations at temperatures of 70 to 90°C is not high. The investigation shows that tensile strength at breaking point of industrial polyester yarn will decrease in water and in oven at higher temperature; this degradation is lower for yarn with high draw ratio. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Thermal and mechanical properties of blends of polylactide and poly(ethylene glycol‐co‐propylene glycol): Influence of annealing
Authors: Ran Xianghai , Jia Zhiyuan , Han Changyu , Yang Yuming , Dong Lisong
Published: January 2010

Two kinds of polylactide (PLA) which was named PLA1 with L‐lactide content of 98% and PLA2 with L‐lactide content of 88% were blended with poly(ethylene glycol‐co‐propylene glycol) (PEPG) in a batchwise mixer and pressed into films. The effect of annealing on the thermal properties, crystallization behavior, and mechanical properties of the quenched blends were studied by means of differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), polar optical microscopy (POM), and tensile tests. PEPG was miscible with the two kinds of PLA in the blend composition range of 5–20 wt % and can effectively decrease the glass transition temperature of PLA. Neat PLA2 lost the ability to crystallize in the DSC and DMA measurements; however, it could crystallize after annealing for long time and crystallize more easily due to the improved crystallizability with the addition of PEPG. Both of the PLAs underwent cold crystallization when annealing at 90°C, and there were signs of phase separation occurring in the blends at the same time. The crystallization morphology and tensile properties of the annealed blends were different and dependent of the optical purity of PLA. The blends with PLA2 after annealing regained the brittleness with maximum of elongation at break about 20% and showed larger spherulites in the POM images, whereas the blends with PLA1 after annealing still kept some flexibility with maximum of elongation at break about 65% and showed fine spherulites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Thermal stability of poly(vinyl chloride)/layered double hydroxide nanocomposites
Authors: Liu Jun , Chen Guangming , Yang Jiping , Ding Liping
Published: January 2010

Effects of nanoscale dispersed layered double hydroxides (LDHs) on thermal stability of poly(vinyl chloride) (PVC) in thermal and thermooxidative degradation processes are investigated by dynamic and isothermal thermogravimetric analysis (TGA), discoloration test, fourier transform infrared (FTIR), and ultraviolet‐visible (UV‐vis) spectroscopic techniques. During both stages of thermal degradation, the degradation temperatures, including onset degradation temperature and temperature of the maximum degradation rate, increase, and the final residue yield of the PVC/LDH nanocomposites reaches 14.7 wt %, more than double that for neat PVC. The thermooxidative degradation process is more complex. During the first two stages, the presence of nanoscale dispersed LDH particles enhances the thermal stability, whereas in the last stage accelerates the thermal degradation possibly due to the accumulation of heat released. Additionally, the studies of the isothermal thermooxidative degradation process by FTIR and UV‐vis spectra indicate that both polyene backbone formation and some carbonyl groups are simultaneously developed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation, characterization, and in vitro application of composite films based on gelatin and collagen from natural resources
Authors: Haroun A. A. , Beherei H. H. , El‐Ghaffar M. A. Abd
Published: January 2010

This work aims to prepare and characterize a new generation composite films with gelatins extracted from bovine and bird bones (Gb and Gc, respectively) in addition to collagen, hide powder, (HP) which are blended with copolymerized polyethylene (MPE) and low density polyethylene, using polymer melt technique, which may be suitable for application as a base material for dental and orthopedic implants with better biological response. The bone‐bonding ability of the composite films was evaluated by examining the ability of apatite to form on their surface in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma. The examination of apatite formation on the composites after immersion in SBF for 7 days was carried out by Fourier transform infrared spectroscopy and scanning electron microscopy with energy dispersive X‐ray. The results showed the formation of thick apatite layer on the surface of the biocomposite films in special way on these containing Gb/MPE and collagen/MPE. Promising results have been achieved indicating that these novel biocomposites have unique bioactivity properties, which can be applied in bone implants and tissue engineering applications as scaffolds in future. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The water vapor sorption behavior of flax fibers—Analysis using the parallel exponential kinetics model and determination of the activation energies of sorption
Authors: Hill Callum A.S. , Norton Andrew , Newman Gary
Published: January 2010

Sorption kinetic data for the interaction of water vapor with flax (Linum usitatissimum L.) were analyzed used the parallel exponential kinetics (PEK) model, with excellent fits to the data being obtained. The PEK model is the sum of two exponential kinetics processes (fast and slow), which have characteristic times and moisture contents associated with them. The slow adsorption and desorption processes exhibited important differences in their characteristic times, although hysteresis in the moisture contents was found to be predominantly associated with the fast process. The kinetics was examined over a range of relative humidity (RH) values and at different temperatures, enabling the determination of activation energies for the adsorption and desorption kinetic processes throughout the hygroscopic range (from 5–95% RH). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Interleukin‐27 inhibits human osteoclastogenesis by abrogating RANKL‐mediated induction of nuclear factor of activated T cells c1 and suppressing proximal RANK signaling
Authors: Kalliolias George D. , Zhao Baohong , Triantafyllopoulou Antigoni , Park‐Min Kyung‐Hyun , Ivashkiv Lionel B.
Published: January 2010

Objective

Interleukin‐27 (IL‐27) has stimulatory and regulatory immune functions and is expressed in rheumatoid arthritis (RA) synovium. This study was undertaken to investigate the effects of IL‐27 on human osteoclastogenesis, to determine whether IL‐27 can stimulate or attenuate the osteoclast‐mediated bone resorption that is a hallmark of RA.

Methods

Osteoclasts were generated from blood‐derived human CD14+ cells. The effects of IL‐27 on osteoclast formation were evaluated by counting the number of tartrate‐resistant acid phosphatase–positive multinucleated cells and measuring the expression of osteoclast‐related genes. The induction of nuclear factor of activated T cells c1 (NFATc1) and the activation of signaling pathways downstream of RANK were measured by immunoblotting. The expression of key molecules implicated in osteoclastogenesis (NFATc1, RANK, costimulatory receptors, and immunoreceptor tyrosine–based activation motif–harboring adaptor proteins) was measured by real‐time reverse transcription–polymerase chain reaction. Murine osteoclast precursors obtained from mouse bone marrow and synovial fluid macrophages derived from RA patients were also tested for their responsiveness to IL‐27.

Results

IL‐27 inhibited human osteoclastogenesis, suppressed the induction of NFATc1, down‐regulated the expression of RANK and triggering receptor expressed on myeloid cells 2 (TREM‐2), and inhibited RANKL‐mediated activation of ERK, p38, and NF‐κB in osteoclast precursors. Synovial fluid macrophages from RA patients were refractory to the effects of IL‐27. In contrast to the findings in humans, IL‐27 only moderately suppressed murine osteoclastogenesis, and this was likely attributable to low expression of the IL‐27 receptor subunit WSX‐1 on murine osteoclast precursors.

Conclusion

IL‐27 inhibits human osteoclastogenesis by a direct mechanism that suppresses the responses of osteoclast precursors to RANKL. These findings suggest that, in addition to its well‐known antiinflammatory effects, IL‐27 plays a homeostatic role in restraining bone erosion. This homeostatic function is compromised under conditions of chronic inflammation such as in RA synovitis.
Cardiac involvement in Churg‐Strauss syndrome
Authors: Dennert Robert M. , van Paassen Pieter , Schalla Simon , Kuznetsova Tatiana , Alzand Becker S. , Staessen Jan A. , Velthuis Sebastiaan , Crijns Harry J. , Tervaert Jan Willem Cohen , Heymans Stephane
Published: January 2010

Objective

Churg‐Strauss syndrome (CSS) is a rare form of systemic vasculitis. Previous studies showing cardiac involvement in CSS patients were limited in the number of patients and were often based solely on clinical manifestations. The aim of the present study was to determine in detail the incidence of cardiac involvement in a large population of ambulatory CSS patients.

Methods

Thirty‐two consecutive patients with CSS in remission (mean ± SD duration of disease between diagnosis and enrollment 6.1 ± 5.8 years, mean ± SD age 61 ± 10 years) who were previously unaware of cardiac involvement were compared with 32 randomly selected age‐ and sex‐matched control subjects, using clinical evaluation, electrocardiography (EKG), echocardiography, and cardiac magnetic resonance imaging (MRI).

Results

Detailed cardiac evaluation revealed a 62% prevalence of cardiac involvement in CSS patients compared with 3% in controls (P < 0.001), with clinical symptoms in 26% and 3%, respectively (P = 0.009), EKG abnormalities in 66% and 3%, respectively (P < 0.001), and echocardiographic defects in 50% and 3%, respectively (P < 0.001). Cardiac MRI detected cardiac manifestations in 62% of CSS patients. In the presence of cardiac MRI abnormalities, echocardiography could detect cardiac involvement with a sensitivity of 83% and a specificity of 80%. The absence of symptoms or EKG abnormalities did not exclude cardiac involvement, because abnormalities could still be detected in 38% of these patients at the time of echocardiography or cardiac MRI.

Conclusion

These results demonstrate a high incidence of cardiac involvement in CSS patients. Systematic cardiac evaluation including detailed imaging is required to properly identify CSS patients with cardiac involvement.
Biologic predictors of extension of oligoarticular juvenile idiopathic arthritis as determined from synovial fluid cellular composition and gene expression
Authors: Hunter Patricia J. , Nistala Kiran , Jina Nipurna , Eddaoudi Ayad , Thomson Wendy , Hubank Mike , Wedderburn Lucy R.
Published: January 2010

Objective

To identify biomarkers in the first synovial fluid (SF) aspirate obtained from children with oligoarticular juvenile idiopathic arthritis (JIA), which could be used to identify children whose disease is likely to extend to a more severe phenotype.

Methods

Patients with recent‐onset oligoarticular JIA were identified and grouped according to those whose mild disease persisted (persistent disease) or those whose disease would extend from a mild to more severe phenotype (extended‐to‐be disease) at 1 year after diagnosis. Flow cytometry was used to delineate differences in the mononuclear cell populations between the first blood sample and first SF aspirate from the same patient and between outcome (persistent versus extended‐to‐be) groups. Proportions of lymphocytes in the joint were modeled on chemotaxis of lymphocytes to CCL5, using Transwell migration assays. Levels of CCL5 in the SF were quantified by enzyme‐linked immunosorbent assay. RNA profiles of SF mononuclear cells were compared between groups using the Affymetrix GeneChip hybridization protocol and hierarchical clustering analyses.

Results

Compared with peripheral blood mononuclear cells, SF mononuclear cells displayed an expansion of CD8+ T cells, reduced proportion of B cells, and expansion of CD16− natural killer cells. The lower CD4:CD8 ratio in the SF was recapitulated in vitro by the observed migration of blood T cells in response to CCL5. Synovial CCL5 levels were higher in children whose disease extended to a more severe phenotype. The CD4:CD8 ratio in the SF was significantly lower in patients with extended‐to‐be oligoarticular JIA (0.57 compared with 0.90 in the persistent disease group, difference 0.33, 95% confidence interval 0.04–0.62; P = 0.009). Gene expression profiling revealed that 344 genes were >1.5‐fold differentially expressed between outcome groups (P < 0.05), and these included genes associated with inflammation and macrophage differentiation, which showed increased levels in patients with extended disease at 1 year, and genes associated with immune regulation, which showed increased levels in patients with persistent disease at 1 year.

Conclusion

Analyses of the proportions of synovial lymphocytes, levels of CCL5, and differential gene expression yielded potential biomarkers with which to predict the likelihood of extension of oligoarticular JIA to a more severe disease phenotype.
Near‐peer role modeling: The fledgling scholars education paradigm
Authors: Singh Satendra
Published: January 2010

Peer‐assisted learning as de rigueur is reverberating in medical institutions around the world. Anatomy classroom activities are challenging and different, and the stressful environment of dissection rooms poses a greater challenge than what can be addressed through peer‐assisted learning. It is here that “near‐peer role modeling” is not only likely to be more useful, both to the students as well as their near‐peer teachers, but also holds the answer to the worsening faculty shortage in anatomy education. Anat Sci Educ 3:50–51, 2010. © 2010 American Association of Anatomists.
Unnatural Polyketide Analogues Selectively Target the HER Signaling Pathway in Human Breast Cancer Cells
Authors: Kwon Seok Joon , Kim Moon Il , Ku Bosung , Coulombel Lydie , Kim Jin‐Hwan , Shawky Joseph H. , Linhardt Robert J. , Dordick Jonathan S.
Published: January 2010

Receptor tyrosine kinases are critical targets for the regulation of cell survival. Cancer patients with abnormal receptor tyrosine kinases (RTK) tend to have more aggressive disease with poor clinical outcomes. As a result, human epidermal growth factor receptor kinases, such as EGFR (HER1), HER2, and HER3, represent important therapeutic targets. Several plant polyphenols including the type III polyketide synthase products (genistein, curcumin, resveratrol, and epigallocatechin‐3‐galate) possess chemopreventive activity, primarily as a result of RTK inhibition. However, only a small fraction of the polyphenolic structural universe has been evaluated. Along these lines, we have developed an in vitro route to the synthesis and subsequent screening of unnatural polyketide analogues with N‐acetylcysteamine (SNAc) starter substrates and malonyl‐coenzyme A (CoA) and methylmalonyl‐CoA as extender substrates. The resulting polyketide analogues possessed a similar structural polyketide backbone (aromatic‐2‐pyrone) with variable side chains. Screening chalcone synthase (CHS) reaction products against BT‐474 cells resulted in identification of several trifluoromethylcinnamoyl‐based polyketides that showed strong suppression of the HER2‐associated PI3K/AKT signaling pathway, yet did not inhibit the growth of nontransformed MCF‐10A breast cells (IC50>100 μM). Specifically, 4‐trifluoromethylcinnamoyl pyrone (compound 2 e) was highly potent (IC50<200 nM) among the test compounds toward proliferation of several breast cancer cell lines. This breadth of activity likely stems from the ability of compound 2 e to inhibit the phosphorylation of HER1, HER2, and HER3. Therefore, these polyketide analogues might prove to be useful drug candidates for potential breast cancer therapy.
ChemInform Abstract: Matrix Infrared Spectroscopic and Computational Investigation of Late Lanthanide Metal Hydride Species MHx(H2)y (M: Tb—Lu, x = 1‐4, y = 0‐3).
Authors: Wang Xuefeng , Andrews Lester , Infante Ivan , Gagliardi Laura
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Magnetic Transitions in the Gd5Si4‐xPx (x = 0.5, 0.75, 1.25) Phases. Magnetocaloric Effect of the Gd5Si2.75P1.25
Authors: Svitlyk Volodymyr , Mozharivskyj Yurij
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Characterization of Eu‐Doped Hydroxyapatite Through a Microwave Assisted Microemulsion Process.
Authors: Yang Chun , Yang Piaoping , Wang Wenxin , Gai Shili , Wang Jun , Zhang Milin , Lin Jun
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Growth of Ln3GaO6 (Ln: Nd, Sm, Eu and Gd): Structural and Optical Properties.
Authors: Zeier Wolfgang G. , Roof Irina P. , Smith Mark D. , zur Loye Hans‐Conrad
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis, Characterization and Magnetic Properties of Complex Oxides Ln2Mn2/3Re4/3O7 (Ln: Er, Y) and Y2Zn2/3Re4/3O7.
Authors: Bazuev G. V. , Chupakhina T. I. , Korolyov A. V.
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: One‐Pot Desymmetrization of meso‐1,2‐Hydrocarbon Diols Through Acylation and Oxidation.
Authors: Mueller Christian E. , Zell Daniela , Schreiner Peter R.
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: 2‐(Phenylseleno)‐1,4‐dioxane as a Convenient Reagent for the Selective Protection of Alcohols as 1,4‐Dioxan‐2‐yl Ethers.
Authors: Temperini Andrea , Terlizzi Raffaella , Testaferri Lorenzo , Tiecco Marcello
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Palladium Complexes with Abnormal N‐Heterocyclic Carbene Ligands Derived from 1,2,3‐Triazolium Ions and Their Application in Suzuki Coupling.
Authors: Karthikeyan Thandavamurthy , Sankararaman Sethuraman
Published: January 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.