bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Silver Nanoparticle Sizes on Antibacterial Activity, Cytotoxicity and Genotoxicity of Alginate Hydrogel Beads Containing Silver Nanoparticles
Authors: Mahasawat Pawika , Mudtaleb Soraya , Eaidprap Pratumporn
Published: January 2019

Sizes of silver nanoparticles (AgNPs) have been shown to affect the biological activity of AgNPs. Hydrogel beads loaded with AgNPs have been extensively employed for biomedical applications. However, the influence of AgNPs sizes on biological activity of AgNP-loaded hydrogel beads has not much studied. Our objectives were to investigate the effect of AgNP sizes on the antibacterial activity, the cyto- and genotoxicity of AgNPs/alginate hydrogel beads. AgNPs of different sizes (⁓10 nm for S-AgNPs, and ⁓50 nm for L-AgNPs) were incorporated into alginate hydrogel beads during the preparation. The results showed that, S-AgNPs/alginate hydrogel beads (⁓89% inhibition) at AgNP concentration of 10 µg/ml tended to inhibit the growth of E. coli greater than L-AgNPs/alginate hydrogel beads (⁓49% inhibition) at the same dose. Moreover, at this effective antibacterial concentration (10 µg/ml), S-AgNPs/alginate hydrogel beads exhibited weak cytotoxic effect to HaCaT cells whereas L-AgNPs/alginate hydrogel beads showed non-cytotoxicity to this cell line. Furthermore, treatment of HaCaT cells with 10 µg/ml of S-AgNPs/ or L-AgNPs/alginate hydrogel beads did not result in a significant change in %DNA in tail when compared to untreated cells. Therefore, these AgNPs/alginate hydrogel beads, especially with smaller sized AgNPs, can be used as an antibacterial biomaterial with low cytotoxicity and genotoxicity to human cells.
Estimation of Evaporative Loss of Surface Water Using Stable Isotopes in a Lowland Rice Field, Suphanburi, Thailand
Authors: Porntepkasemsan Boonsom , Kulsawat Wutthikrai , Nochit Phatchada
Published: January 2019

Water scarcity resulting from erratic rainfall pattern is a major problem over the world. As diminishing water resources for agriculture and increasing demand for rice yield, understanding on hydrological cycle is crucial on water management. The loss of water due to evaporation from rivers and canals constitutes a substantial part of useable water. The estimated evaporation loss can be obtained by using the isotope compositions of precipitation and an established local evaporation line. It is recognized a very useful tool in providing a quick and cost effective insight into the water balance of surface water pool. In this study of 2015-2017 in Suphanburi province, the isotopic signatures of precipitation and surface water canal resulted in a local meteoric water line of δ2H = 7.63 δ18O – 1.05 (n = 168, r2= 0.94) and local evaporation line for surface water creek of δ2H = 5.95 δ18O – 14.42 (n = 155, r2= 0.90), respectively. The estimated evaporation loss using theHydrocalculatorsoftware indicated that the estimated fractional water loss by evaporation in the surface water canal of Sri Prachan district, Suphanburi was ~12%.
Numerical Studies on Cavitation and Surface Roughness
Authors: Joy Jithin Ambarayil , Mathaiyan Vijayakumar , Sajjad Muhammad , Jung Dong Won
Published: January 2019

The study of cavitation is of topical interest in both physical and biological sciences. The surface roughness changes the effect of cavitation on a material surface. Due to cavitation, the material with low surface roughness value has relatively more damage, when compared to the one with higher value. In this paper, preliminary numerical studies are carried on cavitation and surface roughness. As a part of the code validation and calibration, the numerically predicted boundary-layer blockage at the Sanal flow choking condition for the channel flow is verified using the closed-form analytical model of V.R. Sanal Kumar et al. (AIP Advances, 8, 025315, 2018) at various surface roughness and found excellent agreement with the exact solution. Parametric analytical studies are carried out for examining the flow features at two different surface roughness and turbulence levels. We noticed that the wavy surface with small waves increases the Nussle number, therefore it is also considered for parametric analysis. Considering the defect-free smooth surface material, we presumed that the cavitation damage in the smooth surface is more than the rough surface because the smooth surface can generate more micro bubbles. These micro bubbles grow into macro bubbles which in turn results in cavitation. This study is a pointer towards for formulating various industrial topics with fluid-structural interaction problems for getting plausible solutions for meeting the needs of various industries.
Ti-Zr-V-Cu-Be BMGMCs Processed by Semi-Solid Processing
Authors: Guo Hong Min , Bai Le Rong , Liu Bin , Yang Xiang Jie
Published: January 2019

Compared with monolithic bulk-metallic glasses at room temperature, in-situ two-phase bulk metallic glass matrix composites (BMGMCs) exhibit improved toughness. However, most of in-situ BMGMCs are developed through extremely rapid cooling, during which the solidification process cannot be controlled effectively. As a consequence, the microstructures of in situ two-phase composites, even with the same composition, vary from one to another, highly depend on the cooling rate. In the present investigation, the Ti-Zr-V-Cu-Be BMGMCs was prepared by using copper mould suction process, and the evolution of microstructures at semi-solid stage was investigated. The results indicated that microstructures of billets, produced by copper mould suction and water quenching after isothermal holding at semi-solid stage, mainly contained β-Ti phase and glass matrix. Isothermal holding temperature and time interval determined the final morphology of β-Ti phase. Compression tests showed that semi-solid processing could further improve ductility of BMGMCs effectively.
Microstructure Evolution of TiB2/7075 Composites in Semi-Solid State near Liquids within Holding Time
Authors: Gan Gui Sheng , Xia Da Quan , Liu Xin , Liu Cong , Cheng Han Lin , Ming Zhong Zhen , Gao Hao Yang , Yang Bin
Published: January 2019

Novel reactive technique has been employed in synthesis of 7075 Al matrix composites, and effect of TiB2 particles on sedimentation and microstructure of 7075 Al Alloy in near liquidus was investigated. Researchers have shown that 4.5%TiB2/7075 composites had the smallest grains and the minimum liquidus and solidus temperatures in 7075 Al matrix composites. 4.5%TiB2/7075 composites holding for 21 hours appeared stratification phenomenon, the globular grains were 61μm and 214μm, 250μm and 283μm with the increase of holding time respectively. The microstructures evolution of TiB2 /7075 composites holding for different time at 635°C was a two-stage mechanism that the globular grains was formed firstly and secondly sedimentation and layering were began after a period of time of Ostwald ripening. The globular grain continued to increase during the settling process.
SIMA Processing of Cu34wt.%Zn2wt.%Pb Brass Alloy
Authors: Tavakkoli Hamid , NIROUMAND BEHZAD , Rezaeian Ahmad
Published: January 2019

Effects of SIMA processing on size and shape of primary solid particles of Cu34wt.%Zn2wt.%Pb brass alloy was investigated. The optimal temperature for semisolid processing of the alloy was found to be around 890 °C using Thermo-calc simulation software. Liquid fraction sensitivity of the alloy around this temperature is 0.012. The results indicated the formation of non-dendritic microstructure even after 1 min holding of 10% cold worked sample at 890 °C. Sphericity of the primary solid particles increased by increasing the cold working ratio and holding time. The smallest size (103 μm) and highest shape factor (0.84) of the primary solid particles were achieved at 30% cold working ratio and 5 min holding time.
Manufacture of Continuous Metal Matrix Composite Strip Reinforced by Particulate Materials from the Semisolid Processing
Authors: de Pádua Lima Filho Antonio , Ueda Bruno Katsuyoshi Silama , de Castro Tales Paschoalino , de Oliveira Rodrigo Alessandro Nunes
Published: January 2019

Strip casting is a new method of producing metal matrix composites. Two-roll melt dragged processing (TRMD-ing) and single-roll melt dragged processing (SRMD-ing) methods were used to study the manufacture of 2-mm-thick composite strips by using PbSn (≈ 11.3 g/cm3) eutectic alloy matrix reinforced with iron (≈ 7.86 g/cm3) powder (≈ 70 μm) at a rate of 0.3 m/s. The metallic powder stored in the feed hopper (≈ 90 g) was pushed during the pouring operation of the cast alloy (≈ 4 kg) at 260 oC on the cooling slope to produce a mixture of metallic slurry and particles to feed the nozzle to be dragged by the lower roll. Various surface defects occurred during processing, such as the failure of the powder particle to be embedded in the matrix by SRMD-ing with and without stirrer into the nozzle, and the rolling up of the strip into the nozzle by TRMD-ing. Graphite nanoparticles formed inside the α-Pb grain revealed a complicate eutectic structure in both the processing methods. The colloidal graphite used to coat the crucible, cooling slope, and nozzle could act as a nucleation agent for preferential centre segregation in the α-Pb grain. This suggests that the graphite nanoparticles functioned as nucleation points in the lead-rich α phase. Thus, another type of composite was formed in the presence of graphite nanoparticles within the lead-rich α-phase surrounded by β-Sn. An electron probe microanalysis and scanning electronic microscopy were used to investigate the composition and distribution and identify the different phases. Several types of particulate reinforcements may be added to the matrix to obtain composites for mechanical, electronic, and magnetic applications using these technologies.
Semi-Solid Slurry Casting Using Gas Induced Semi-Solid Technique to Enhance the Microstructural Characteristics of Al-4.3Cu Alloy
Authors: Abdi M. , Shabestari S.G.
Published: January 2019

Semi-solid processing of Al-4.3%Cu (A206) alloy was performed by Gas Induced Semi-Solid (GISS) process in different condition. The flow rate of argon gas, starting temperature for gas purging (the temperature of superheated-melt) and the duration of gas purging were three key process variables which were changed during this investigation. It was found that inert gas purging near liquidus, significantly, led to the microstructural modification from fully dendritic to globular structure. Thermal analysis was successfully implemented through CA-CCTA technique to understand the cause of the microstructure change during GISS process. The results showed that gas purging into the melt leads to temperature drop of the melt to its liquidus just after a few seconds from start of gas purging. In fact, copious nucleation was induced by cooling effect of inert gas bubbles. Microstructural features were characterized in semi-solid as well as on conventionally cast samples. The optimum gas purging temperature, injection time, and inert gas flow rate was determined in semi-solid processing to obtain the best globularity in the microstructure of a long freezing range alloy. However, the microstructure of the conventionally cast sample was fully dendritic with shrinkage which affects the soundness of casting products.
Fabrication of Lotus Type Porous Ingots Using the Core-Bar Pulling Method
Authors: Haga Toshio , Fuse Hiroshi
Published: January 2019

The application of the core-bar pulling method to Al-Mg, Al-Mn, Al-Cu and Cu-Zn alloys was investigated, using a stainless steel core-bar with a 2 mm diameter to produce through-holes in 50 mm long ingots. This study confirmed that through-holes could be produced in these alloys in this manner. The results demonstrate that the temperature ranges over which the core-bar can be extracted are quite wide, so precise control of the ingot temperature is not required when producing through-holes. The core-bar pulling method is evidently a facile means of fabricating through-hole lotus type porous metals.
Development of Slurry Preparation Method by Applying Mechanical Vibration
Authors: Murakami Yuichiro , Miwa Kenji , Kito Masayuki , Honda Takashi , Omura Naoki
Published: January 2019

The preparation of a semi-solid slurry with fine and spherical solid particles dispersed in the liquid phase is a key technology for the semi-solid process. In this study, we have developed the slurry preparation method by applying mechanical vibration for JIS AC4CH (equivalent to A356 in the ASTM standard) and ADC12 (equivalent to A383 in the ASTM standard) aluminum alloys. In this method, the mechanical vibration was applied to the aluminum alloys during cooling from a liquid state to semi-solid state. The shape of the particle was varied by controlling vibration conditions. Therefore, we investigated the effect of conditions on mechanical vibrations. There are four parameters which are frequency, acceleration amplitude, velocity amplitude and displacement amplitude in the mechanical vibration. Among these parameters, the velocity amplitude had highest effects on the shape of solid particles. By properly controlling of the frequency and the velocity amplitude, the slurry with fine and spherical solid particles could be obtained. Moreover, the fraction solid of slurry could be controlled by varied initial liquid temperature. Especially, ADC12 aluminum alloy has low liquid-solid coexistence temperature range, so it is not considered to be suited for the semi-solid process. However, by using this mechanical vibration method, the semi-solid slurry could be obtained stably. This method is expected to be effective for the semi-solid high-pressure die-casting process.
Rheological Investigation of Semisolid AlSi7 Alloy by Means of Oscillation Experiments
Authors: Tocci Marialaura , Pola Annalisa , Modigell Michael
Published: January 2019

Dynamic Mechanical Analysis (DMA) of semisolid aluminum alloys was performed in a rheometer of Searle type. DMA was applied on a binary AlSi7 alloy to demonstrate the advantages of the method for the investigation of the behavior of alloys in semi-solid state and it was compared to classical shear experiments. Frequency sweeps, amplitude sweeps as well as constant condition experiments (CCE) were performed. It became obvious that elastic properties are getting more dominant with increasing resting time without shearing. The shift from a more viscous to more elastic nature of the material can be quantified. Interestingly, it was found that the semi-empirically based Cox-Merz rule, usually applied for polymers, holds for the semisolid material as well. This allows investigating the shear viscosity under different relevant conditions - important to improve material models for die-filling simulation of semisolid alloys.
The Status of Magnesium Injection Molding in China
Authors: Zhu Yi Bing , Midson Stephen P.
Published: January 2019

Thixomolding, or magnesium injection molding as it is more generally known, is an established semi-solid casting process for producing thin-walled near net shape components from magnesium alloys. Magnesium injection molding produces components using a machine similar to a plastic injection molder, where magnesium-alloy chips are feed into the back end, and a rotating screw feeds the chips forward as they are heated to the semi-solid temperature range. The semi-solid alloy collects in a nozzle at the front of the screw, where it is then injected into a re-usable steel die. This paper will initially describe the commercial status of magnesium injection molding in China, and will review several types of components being produced commercially. Comparisons to conventional hot chamber magnesium die casting will be made, and a new magnesium injection molding machine design that incorporates an intensifier will be introduced. In addition, new technology trends utilizing the magnesium injection molding process will be described. One such application involves the magnesium injection molding of Mg-Li alloys. Lithium has the lowest density of all metals, and so the addition of lithium further reduces the density of the magnesium.
Case Study: Engine Bracket Made by Rheocasting Using the SEED Process
Authors: Côté Pascal , Vlastimil Bryksi , Bryksí Stunová Barbora
Published: January 2019

In the context of increasing needs for lightweighting vehicles, semisolid casting of aluminium components is a proven route that can be efficiently applied for automotive parts. Although semisolid forming has not yet reached the market penetration that suits its actual potential, it is currently and efficiently used in many applications around the world on a daily basis. An example of such will be shown. This paper presents a case study on the application of the SEED rheocasting technology for the casting of an engine bracket. The part is made of the widely used AlSi7Mg0.3 alloy and is heat treated in T6 condition to benefit from the enhanced mechanical properties made possible by semi-solid forming. Throughout the development phase, different aspects associated with semisolid casting, such as slurry condition, gate design, mold filling behaviour, lubrication, blistering and others, were addressed successfully. In the final, the combination of the SEED technology with a thorough development process and the specific casting rules for semi-solid forming led to actual commercial production and contributed to weightsaving on the actual part as compared to a former design made from high pressure die casting.
Analysis of the Influence of Surface Finishing on the Performances of Dies for HPDC
Authors: Gobber Federico Simone , Ugues Daniele , Rosso Mario
Published: January 2019

The Al-alloy die casting die is a sector where the operating environment imposes a very severe aggression to hot working tools. Steel grades for such application, techniques for their surface modification and specifically conceived lubricants are continuously improved so as to limit Al soldering. Within this scenario the interaction between lubricant and die surface and the effect of finishing levels of such surface is poorly studied. This paper deals with a study of the influence of dies surface roughness on the working behavior of a die casting lubricant and on surface damages of a tool steel grade. Tool steel samples were prepared for the research and two different levels of surface roughness (as polished and as finely sand blasted) were investigated. Apart from the base characterization of steels and surface, two specific test rigs were used to study the lubricant-tool steel surface-Al alloy interactions. One of test rig was devoted to study the coupling principles of tool die surface-lubricant, while the other test rig was used to perform a cyclic immersion test in molten Al-alloy. The derived data were compared to the experimental investigation of cracks and craters as provided by cycling with a correlation with the surface finishing level of samples.
Thixoforming of Aluminum A201- Expectations and Fulfilment
Authors: Kapranos Plato
Published: January 2019

Thixoforming as a Semi-Solid Metal Processing (SSM) route is a near net shape forming of metals in the semi-solid state, i.e. within the freezing or melting range between the fully solid and fully liquid states. Aluminum A201 is a copper containing casting alloy with additional small quantities of magnesium, silicon and silver. Although this alloy is difficult to cast, it has a particularly high response to age-hardening and therefore offers mechanical properties close to the wrought 2014 alloy. Alloy development experiments carried out at the University of Sheffield on A201 alloy have shown that feedstock of this alloy can be produced having uniform non-dendritic microstructures amenable to thixoforming, exhibits thixotropic properties under these conditions, can be shaped into complex near net-shape parts and develops impressive mechanical properties after appropriate heat treatment. A201 aluminum alloy billets when thixoformed in the semi-solid state and heat treated with a T7 followed by T6 treatment before being mechanically tested, have exhibited properties approaching those of wrought 2000 series aluminum alloys. Here follows a review of work done to date on shaping the A201 aluminum alloy in the semi-solid state, describing the hopes, expectations and fulfilment of researchers in the field.
Semisolid Processing of Magnesium Alloys: Progress and Limitations
Authors: Czerwinski Frank
Published: January 2019

An application of semisolid processing to magnesium alloys is described, emphasizing both the fundamental aspects and up-to-date successful industrial applications. The key advantages of the semisolid route are discussed, including longer tool life, tighter dimensional tolerances and better process consistency. The particular attention is paid to reduced temperature of semisolid processing, providing common benefits for magnesium alloys due to their high affinity to oxygen, requiring an expensive protection and leading otherwise to ignition and burning. Major microstructural factors controlling properties of magnesium alloys after semisolid processing are considered. It is concluded that although the reduced temperature results in higher part integrity, it does not create beneficial microstructural characteristics converting to substantially improved mechanical properties.
Wear Properties of Thixoformed Al-5.7Si-2Cu-0.3Mg Aluminium Alloy
Authors: Abdelgnei Mnel A. , Omar M. Zaidi , Ghazali Mariyam Jameelah
Published: January 2019

Earlier work has shown that Al-5.7Si-2Cu-0.3Mg aluminium alloy is suitable for thixoforming process. Here, the dry sliding wear behaviour of the alloy, in the as-cast and thixoformed conditions were investigated. The cooling slope technique was used to produce the alloy with globular microstructure for the thixoforming process. Both the thixoformed and cast samples were subjected to T6 heat treatments prior to the wear tests. The tests were carried out using a pin-on-disc tribometer, against a hardened M2 tool steel disc of 62 HRC at different loads, under dry sliding conditions at fixed sliding speed and sliding distance of 1 m.s–1 and 5 km respectively. The microstructural response, worn surfaces were thoroughly and carefully examined using various methods such as scanning electron microscopy, energy dispersive spectroscopy, and differential scanning calorimetry. The density of the heat treated thixoformed alloys showed significant increase in the hardness property, among others, due to its reduced porosity. Their wear test results also observed that the weight loss of materials increase with an increase in the input load and the sliding distance for all samples. However, the as-cast alloy displayed higher wear rate compared with the thixoformed alloys. In general, the wear mechanisms showed a mixture of abrasive, oxidative and delamination wear (mild wear) at low applied loads and mainly an adhesive (severe wear) at high applied loads.
Characterization of Subpopulations of Chicken Mononuclear Phagocytes That Express TIM4 and CSF1R
Authors: Hu Tuanjun , Wu Zhiguang , Bush Stephen J. , Freem Lucy , Vervelde Lonneke , Summers Kim M. , Hume David A. , Balic Adam , Kaiser Pete
Published: January 2019

The phosphatidylserine receptor TIM4, encoded by TIMD4, mediates the phagocytic uptake of apoptotic cells. We applied anti-chicken TIM4 mAbs in combination with CSF1R reporter transgenes to dissect the function of TIM4 in the chick (Gallus gallus). During development in ovo, TIM4 was present on the large majority of macrophages, but expression became more heterogeneous posthatch. Blood monocytes expressed KUL01, class II MHC, and CSF1R-mApple uniformly. Around 50% of monocytes were positive for surface TIM4. They also expressed many other monocyte-specific transcripts at a higher level than TIM4− monocytes. In liver, highly phagocytic TIM4hi cells shared many transcripts with mammalian Kupffer cells and were associated with uptake of apoptotic cells. Although they expressed CSF1R mRNA, Kupffer cells did not express the CSF1R-mApple transgene, suggesting that additional CSF1R transcriptional regulatory elements are required by these cells. By contrast, CSF1R-mApple was detected in liver TIM4lo and TIM4− cells, which were not phagocytic and were more abundant than Kupffer cells. These cells expressed CSF1R alongside high levels of FLT3, MHCII, XCR1, and other markers associated with conventional dendritic cells in mice. In bursa, TIM4 was present on the cell surface of two populations. Like Kupffer cells, bursal TIM4hi phagocytes coexpressed many receptors involved in apoptotic cell recognition. TIM4lo cells appear to be a subpopulation of bursal B cells. In overview, TIM4 is associated with phagocytes that eliminate apoptotic cells in the chick. In the liver, TIM4 and CSF1R reporters distinguished Kupffer cells from an abundant population of dendritic cell–like cells.
Are R&D subsidies effective? The effect of industry competition
Authors: Xiang Xin
Published: January 2019

In this study, the author explores the effect of industry competition on public R&D subsidy effectiveness. He finds a non-linear threshold effect of industry competition on R&D subsidy effectiveness. Specifically, R&D subsidy effectiveness reaches its peak when industry competition lies between two estimated thresholds.
Characteristics of peripheral immune cell subsets in patients with carotid atherosclerosis undergoing carotid endarterectomy
Authors: Kotfis Katarzyna , Biernawska Jowita , Zegan-Barańska Małgorzata , Gutowski Piotr , Żukowski Maciej
Published: January 2019

Introduction

The role of circulating immune cells in the pathophysiology of cerebrovascular accidents is currently under debate. The aim of this study was to characterize peripheral immune cell subsets in patients undergoing carotid endarterectomy (CEA).

Material and methods

We conducted a prospective observational study in a group of 124 patients with significant carotid stenosis undergoing carotid endarterectomy, both symptomatic and asymptomatic. We compared the percentages of circulating immune cells: B lymphocytes, T lymphocytes, T helper, cytotoxic T, CD4+/CD8+ ratio, T regulatory, monocytes and NK cells before CEA and 6 h after the procedure.

Results

Total lymphocyte count and cytotoxic T lymphocyte count decreased 6 h after CEA in both subgroups. The NK cell level decrease was statistically significant only in the symptomatic subgroup (19.41 ±9.30 before CEA and 16.52 ±9.37 after CEA; p = 0.0044), but not in the asymptomatic subgroup (17.88 ±9.14 before CEA and 15.91 ±9.51 after CEA; p = 0.0886). The T lymphocyte level showed a statistically significant increase only in symptomatic patients (69.74 ±10.16 before CEA vs. 71.45 ±9.77 after CEA; p = 0.0462), and not in the asymptomatic subgroup (70.08 ±11.19 prior to CEA and 70.21 ±12.35; p = 0.9048). B lymphocyte, helper T lymphocyte and regulatory T (Treg) lymphocyte (CD4+/CD25+) levels showed a significant increase after CEA.

Conclusions

This is the first study to compare circulating immune cells in patients undergoing carotid endarterectomy. Only the symptomatic subgroup experienced a significant decrease in the NK cell level and an increase in the T lymphocyte count after CEA. This study enriches our understanding of immune cell kinetics during carotid endarterectomy.
Autogenously derived regenerative cell therapy for venous leg ulcers
Authors: Kavala Ali , Turkyilmaz Saygin
Published: January 2019

Introduction

Venous leg ulcers (VLUs), which arise from chronic venous insufficiency in the lower limbs, are a major cause of morbidity and significantly negatively impact patients’ health-related quality of life. Treatment of venous ulcers can be either conservative or surgical. Despite appropriate treatment, VLUs can be resistant to healing. Clinical results of treatment of venous foot ulcers with adipose-derived autologous stem cells, which did not improve despite the surgical treatment of the underlying venous pathology in the following case series, are reported.

Material and methods

Between April 2015 and January 2016, a total of 31 patients who had undergone surgery for underlying venous pathology but the venous ulcer had not healed were included in the study. The mean venous ulcer size was 3.6–6.2 cm (range: 2 to 8 cm by 3 to 9 cm). All patients were treated with adipose-derived autologous stem cells prepared using the MyStem Regenerative Adipose-Derived Stem Cell Purification Kit (MyStem LLC, USA). The ulcer diameter was measured and recorded in the third, sixth and twelfth months. The follow-up time was 12 months after ulcer healing.

Results

Eighteen ulcers demonstrated complete healing at the 12th month. Thirteen ulcers exhibited serious contraction and epithelialization even though the ulcer was not completely closed. At the 12th month, the ulcer size was reduced by 96.00 ±1.74% in these patients. The reduction in the ulcer area based on the month analyzed was significant (p = 0.001; p < 0.01). After the ulcers healed, the patients were followed for recurrence for one year. Recurrent ulcers were observed at the treated sites in 3 of 31 patients (9%). No adverse events, such as infection, inflammation, or tissue reactions, were observed.

Conclusions

Application of cell therapy in venous leg ulcer is currently used exclusively in patients not responding to the standard treatment. Autogenously derived regenerative cell therapy for VLUs can be considered as an additional treatment to primary surgical therapy.
The effect of interleukin-1β and interleukin-6 genetic polymorphisms on sickle cell disease course in childhood: an Egyptian study
Authors: Khorshied Mervat , Ibrahim Ola , Gad Alaa , El-Ghamrawy Mona
Published: January 2019

Introduction

Sickle cell disease (SCD) is a chronic inflammatory disorder characterized by altered levels of several inflammatory cytokines, which may be regulated by genetic polymorphisms and could be associated with diverse clinical presentations. Interleukin 1β (IL-1) and interleukin 6 (IL-6) have a pivotal role in the pathogenesis of many acute and chronic diseases, and their genetic alterations have been considered as molecular contributors to several inflammatory disorders. The current study aimed to define the impact of IL-1β and IL-6 genetic polymorphisms on the clinical course of the disease in a cohort of pediatric SCD patients.

Material and methods

Genotyping of IL-1β +3954 C/T and IL-6 –174 G/C polymorphisms was performed by the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) technique for 84 SCD patients and 100 age- and gender-matched unrelated healthy controls.

Results

The polymorphic genotypes of IL-6 –174 G/C were associated with patients suffering from repeated, severe attacks of vaso-occlusion (VOC) requiring hospitalization (p = 0.023 and p = 0.03 respectively), while no significant differences were noted between SCD patients harboring the wild or the polymorphic genotypes of IL-1β +3954 C/T and their demographic, clinical or laboratory characteristics.

Conclusions

IL-6 –174 G/C polymorphism could be considered as a molecular predictor for recurrent, severe attacks of vascular occlusion in Egyptian SCD patients. Considering the important roles of cytokines in SCD pathophysiology, further investigations in larger cohorts are recommended for better characterization of individual variations in immune regulatory genes and identification of novel markers for disease complications and morbidity.
Språkundervisning i förskolan: Teoretiska principer och empiriska exempel
Authors: Björk-Willén Polly , Simonsson Maria , Pramling Niklas
Published: January 2019

I artikeln teoretiseras ett undervisningsbegrepp relevant för förskolans verksamhet. Teoretiskt grundas detta begreppsliggörande i såväl ett evolutionärt som i ett pedagogiskt-psykologiskt perspektiv. Några centrala teoretiker vi bygger på är Barnett, Rommetveit, Tomasello och Vygotskij. Vi lokaliserar grunden till undervisning i människors tendens att göra sådant de själva sett/insett synligt också för andra. Institutioner såsom förskolan och skolan förstås här som sätt för samhället att främja bevarandet av ackumulerande erfarenheter hos den växande generationen, något som gör undervisning centralt. Vi ger empiriska exempel på hur språkundervisning kan gestalta sig i dagens förskola; aktiviteter som vi analyserar utifrån de teoretiska begrepp vi introducerar. Några av de begrepp vi skriver fram för att teoretisera undervisning mer allmänt och språkundervisning mer specifikt i förskolan är responsivitet, kommunikativa praktiker, spänningsfältet mellan intersubjektivitet och alteritet, polyfoni och barns skilda erfarenheter, samt lek och lekfullhet. Vikten av att teoretisera undervisning i förskolan utifrån empirisk forskning betonas.
English abstract
Language teaching in preschool: Theoretical principles and empirical examples
The notion of teaching is theoretically conceptualized in a manner relevant to the context of preschool. This concept is grounded in evolutionary and a pedagogical-psychological theory, with reference to Barnett, Rommetveit, Tomasello, and Vygotsky. The basis of teaching is found in people’s tendencies to make known to others what they themselves have seen/realized. Institutions such as preschool and school are understood as societal means for maintaining accumulated experience with the growing generation, something that puts teaching to the foreground. Empirical examples of language teaching in contemporary preschool are given and analyzed. Some important features of the concept of teaching as here theorized and exemplified are responsivity, language practices, the tension between intersubjectivity and alterity, the variation of children’s experience, play and playfulness. The importance of basing theoretical accounts of teaching as a preschool activity on empirical research is emphasized.
Iscensättning av undervisning: Målrelationellt lärande i förskolan
Authors: Nilsson Monica , Lecusay Robert , Alnervik Karin , Ferholt Beth
Published: January 2019

Förskolan i Sverige har blivit en del av skolväsendet och begrepp från skolans värld överförs till och ska gälla även för förskolan, däribland undervisning och utbildning. Undervisning definieras i skollagen som målstyrda och lärarledda processer. Vi vill med artikeln bidra till kunskapandet om hur undervisning i förskolan kan förstås. Med begreppen iscensättning och målrelationella- kontra målrationella lärandeprocesser analyserar vi delar av ett årslångt utforskande- och lekprojekt i en förskola. Baserat på analysen argumenterar vi för en målrelationell ansats för att tänka kring och arrangera för målstyrda processer i förskolan.
English abstract
Setting the scene for teaching: Goal-relational learning in preschool
Since 1998, preschool provision in Sweden has been supervised through the Ministry of Education. Since then, concepts from compulsory schooling have been formally incorporated in this provision. Teaching, is a particularly striking example, as it is currently applied to preschool based on the definition in the Swedish school law: "teacher-led, goal-oriented processes." This paper contributes knowledge concerning how teaching in preschool can be understood. Drawing on the concepts of staging, and goal-relational versus goal-rationalprocesses, we present analyses of preschool activities documented as part of a year-long project focused on children’s socio-dramatic play and exploration. We argue for a goal-relational approach to thinking about and arranging for goal-directed processes in preschool.
Förskollärarkompetens – skärningspunkt i undervisningens kvalitet
Authors: Williams Pia , Sheridan Sonja
Published: January 2019

Syftet är att analysera undervisning i förskolan. Analyserna utgår från kvalitetsbedömningar med Early Childhood Environment Rating Scale-3 (ECERS-3) (Harms, Clifford och Cryer 2014). Hög kvalitet i förskolan främjar barns lärande inom läroplanens målområden. Artikelns teoretiska ram utgörs av interaktionistiska och ekologiska teorier som innebär att individer och miljö konstruerar varandra i ett dynamiskt och ömsesidigt samspel (Bronfenbrenner 1979, 1986; Bruner 1996; Vygotsky 1986). Undervisning i förskolan definieras i texten som kommunikativ, interaktiv och relationell och behöver förstås i en samhällelig kontext. Kvalitetsbedömningar har genomförts i 153 svenska förskolor med ECERS-3. Resultaten visar att förskolans kvalitet varierar. Låg kvalitet bedöms på aktiviteter som kräver vuxnas engagemang, interaktion och kommunikation med barnen i form av undervisning. Det indikerar att förskollärares kompetens bildar en skärningspunkt för undervisningens kvalitet. Ytterligare forskning behövs för att utveckla förskolans undervisning och didaktik, vilket gynnar såväl barngruppen som enskilda barn och bidrar till en kompetenshöjning hos förskollärarna.
English abstract
Preschool teacher competence – the point of intersection of quality in teaching
The aim is to analyze teaching in preschool. The analysis is based on evaluations of quality with the Early Childhood Environment Rating Scale-3 (ECERS-3) (Harms, Clifford and Cryer 2014). High quality in preschool promotes children’s learning in relation to the objectives of the curriculum. The theoretical framework consists of interactionist and ecological theories that involve individuals and the environment constructively in a reciprocal and continuous interaction (Bronfenbrenner 1979, 1986; Bruner 1996; Vygotsky 1986). Preschool teaching is defined here as communicative, interactive and relational and needs to be understood in a societal context. Quality evaluations have been conducted in 153 Swedish preschools using ECERS-3. The results show that the quality of preschools varies. They visualize a low quality of activities that require adult involvement, interaction and communication with the children in terms of teaching. Preschool teachers’ competences form a point of intersection for the quality of teaching. More knowledge is needed to raise the quality of teaching, which benefits the children and contributes to enhance the competence among preschool teachers.
Blackness and the Pitfalls of Anthropocene Ethics
Authors: Karera Axelle
Published: January 2019

Though to deny the geological impact of human force on nature is now essentially quasi-criminal, many theorists (mostly in the humanities) remain, nonetheless, unimpressed with what this “new era” has afforded us in terms of critical potential. This article is concerned with what Srinivas Aravamudan deems “the escapist philosophy of various dimension of the hypothesis concerning the Anthropocene.” Following Erik Swyngedouw's indictment of apocalyptic discourses' vital role in displacing social antagonisms and nurturing capitalism, this article argues that the new regimes of Anthropocenean consciousness have been powerful in disavowing racial antagonisms. It discusses the ways in which Anthropocene ethics have foreclosed proper political framings by promoting a moral philosophy unequipped to face the racial histories of our current ecological predicament. It contends that the “political Anthropocene” (if there is or ought to be one) will remain an impossibility until it is able to wrestle with the problem of black suffering.
Jewels and Ladders: Visualizing and Resisting the Racialization and Dehumanization of E/Im-migrants and Refugees
Authors: Ortiz John Kaiser
Published: January 2019

While attending seminary school in Pennsylvania, Martin Luther King Jr. cultivated “the arts of pulpit oratory,” the habit of visualizing philosophical problems and other objects of criticism by invoking many-sided jewels and multi-runged ladders. This article appropriates King's jewels and ladders as tools for humanizing juridico-discursive practice toward migrants/emigrants/immigrants and refugees. By drawing attention to the process whereby persons are subordinated and become subpersons, we are able to see how the standpoint of racialized dehumanization is historically patterned and furthermore involves an overlap of legal, political, and artistic expressions. Consequently, jewels and ladders become theoretical as well as practical tools for visualizing the moral standing of migrant/refugee populations in modernity.
Capital Flow Reversals, Sudden Stops, and International Reserve Adequacy: Further Evidence From the Global Financial Crisis
Authors: Efremidze Levan , Sula Ozan , Willett Thomas
Published: January 2019

Using a dataset of 39 emerging markets, we examined the role of international reserves during currency and capital flow crises. Our analysis revealed that higher levels of reserves are associated with lower intensity crises where intensity is measured by the magnitude of the change in exchange market pressure (EMP) or size of capital flow reversals. We also find evidence for the cushioning effects of reserves during the crises. When used against capital flow reversals, reserves can help mitigate the negative output effects of the crisis. Finally, our findings show that reserve adequacy should be evaluated based on the nature of the potential crisis. Policy makers may prefer to refrain from using reserves if export competitiveness is more important than potential balance sheet effects of currency depreciation.
Investigating the Application of Communicative Language Teaching Principles in Primary-Education: A Comparison of CLIL and FL Classrooms
Authors: Guzmán-Alcón Irene
Published: January 2019

It is widely accepted that the learning of a new language, among other advantages, promotes respect and interest of the students towards other cultures and languages. The question is how learning languages can be promoted in educational settings. The aim of the present study is to explore the principles of communicative language teaching in primary-education CLIL and FL classrooms. More specifically, in this paper we address to what extent collaborative work, attention to language and content and corrective feedback are observed during teacher-student and peer interaction in these educational settings. Following an action research approach, ten Spanish and ten Maths sessions were observed and recorded. Furthermore, whole group interaction and peer interaction were analysed in relation to the participants’ attention to language and content. Results from the study show that communicative language teaching is the approach followed in CLIL and FL sessions, tasks being the organizing units. However, differences are observed in relation to attention to language and use of correction strategies. Our findings suggest the need to use strategies to draw attention to language and content in CLIL settings, and the importance of using a more even range of correction strategies both in CLIL and FL classrooms.
Methods of Soybean Genotypes Selection in Paraná State, Brazil
Authors: Lara Lorena M. , Neto Michel Esper , Neto Hugo Zeni , Braccini Alessandro L. , Anghinoni Fernanda B. G. , Santos Rayssa F. , Lima Luiz H. S. , Garcia Alexandre
Published: January 2019

The soybean crop presents several cultivars available. The performance of each cultivar in the field is associated with its genetic characteristics and the interaction of these with environment. Specific recommendations according to environment are made soybean cultivars release based on adaptability and stability analyzes. This research evaluated twelve soybean cultivars in the northern region of Paraná State Brazil, in order to recommend the most suitable and stable cultivar. The experiment was designed in complete randomized blocks four sites: Maringá, Floresta, Cambé and Apucarana, with four replications, in 2017/2018 growing season. Totaling 48 experimental units per site, that is, a total of 192 in the experiment. The variables evaluated were: one thousand grain mass, productivity, hectoliter weight, number of pods per plant and number of grains per plant. The cultivars were evaluated for adaptability and stability by the methodologies proposed by Lin and Binns (1988) and a bi-segmented regression method according to Cruz et al. (1989). The results indicated that the selection was more reliable when the two methodologies were used, due to their correlation coefficients. Soybean cultivar 3 presented promising behavior in regions studied.
Phenolic Composition and Allelopathy of Libidibia ferrea Mart. ex Tul. in Weeds
Authors: Leandro Cícero dos Santos , Bezerra José Weverton Almeida , Rodrigues Maria Daniele Pereira , Silva Ana Karolina Fernandes , Silva Danúbio Lopes da , Santos Marcos Aurelio Figueiredo dos , Linhares Karina Vieiralves , Boligon Aline Augusti , Silva Viviane Bezerra da , Rodrigues Allana Silva , Bezerra Janete de Souza , Silva Maria Arlene Pessoa da
Published: January 2019

Considering the need to produce effective bioherbicides to control weeds and thus reduce the contamination of environments through the use of agrochemicals in control of these plants, the scientific community has been studying the allelopathic activity of several species of Caatinga, once studies indicate that some species of this biome presentind to have activity allelopathic about other plants. On this, the present study aimed to evaluate the allelopathic potential and phenolic composition of extracts of Libidibia ferrea Mart. ex Tul. on seed germination and seedling development of Calotropis procera (Aiton) WT Aiton. and Cenchrus echinatus L. For the allelopathy test, leaf, bark and root extracts, both hot (100 °C) and cold (25 °C), were used, followed by a control group (distilled H2O). Phytochemical prospecting was performed by High Performance Liquid Chromatography (HPLC). The results showed that the hot L. ferrea bark extract has allelopathic activity on C. procera and C. echinatus, which was observed in all parameters analyzed. The phytochemical results showed that L. ferrea extracts present several phenolic compounds which are possibly responsible for the results observed against the two weed species studied, with standing out Gallic acid, Catechin, Caffeic acid, Ellagic acid, and Quercetin. It is therefore necessary to isolate these compounds in view of a potential future use for L. ferrea extracts in the production of a bioherbicide.
Sources of Growth and Spatial Concentration of Coconut Crop in the State of Pará, Brazilian Amazon
Authors: Júnior Paulo Silvano Magno Fróes , Aviz William Lee Carrera de , Rebello Fabrício Khoury , Santos Marcos Antônio Souza dos
Published: January 2019

The State of Pará contributes to approximately 10.10% of the Brazilian production of coconut (Cocos nucifera L.). It is an important center of production for the crop, mainly due to some factors such as its edaphoclimatic conditions that are favorable for the plant development, the availability of rural credit and the presence of business groups with expertise on the activity and agro industrial processing. This survey used data from Instituto Brasileiro de Geografia e Estatística (IBGE) (2018) to make an analysis of the activity in the state between 1974 and 2016, evaluating by the Shift-Share Analysis the sources of production growth, harvested area and productivity. Furthermore, the study also analyses the evolution of coconut prices, concentration and specialization of some micro regions of the State in coconut crop production using the Locational Gini Coefficient and Location Quotient. The main results show an expressive increase in coconut production in the state of Pará economy since the 1980s, showing that between 1974 and 2016 the production increased by 9.41% per year, the harvested area 7.88% p.a. and productivity 1.42% p.a. It is also possible to observe an expressive concentration and specialization of the activity in the Micro region of Tomé-Açu, responsible for 57.40% of the state production.