47 research outputs found
Recommended from our members
Synthesis and Surface Modification of Group IV Nanoparticles Using Non-Thermal Plasmas
No full textThe rapidly increasing interest in silicon nanostructures is motivated by important advantages of this material compared to other semiconductors commonly investigated in the broad field of nanotechnology. Silicon nanoparticles are promising materials for many applications such as photovoltaics, transistors, light emitting devices, and energy storage devices. Commonly used nanoparticle synthesis techniques have many challenges such as high cost, long processing time, and wide particle size distribution. In this dissertation, non-thermal plasma technique is used to overcome these challenges. In this study, in order to produce high quality nanoparticles, the direct comparison of the use of a chlorinated and hydrogenated precursor and its consequences on both the process parameters and material properties are initially investigated. The analysis results show that the chlorinated precursor yields nanoparticles vulnerable against oxidation in air compared to the hydrogenated precursor. In addition, it is found that in the chlorinated precursor case the gas composition needs to be modified and hydrogen needs to be added to the mixture to enable the nucleation and growth of the powder. Silicon nanocrystals with sizes between 5 and 10 nm have been produced in a non-thermal plasma reactor using chlorinated precursor. The properties of the silicon nanoparticles can be tuned through post-processing steps to optimize for targeted applications. In particular surface modification is generally necessary to both tune dispersibility of the particles in desired solvents to achieve optimal coating conditions, and to interface the particles with other materials to realize functional heterostructures. In this contribution a non-thermal plasma-based process for the synthesis of silicon nanoparticles and their in-flight coating with a plasma polymerized shell (silicon/polymer core/shell) has been developed. It is found that it is possible to tune the chemistry of the shell by modifying the gas-phase composition during the polymerization step. These nanoparticles are used as an anode material for lithium-ion batteries. The coating of the silicon particle with a polymer shell offers a way to uniformly disperse the particles into a carbon matrix after high-temperature treatment, which provides an improvement in the stability of an anode for lithium-ion batteries, compared to the case of uncoated silicon particles
Impact of Nanoscale Science and Engineering Course on Undergraduate Engineering Education
No full textBalding Goes Trolling? Cross-Media Amplification of Controversy at the 2012 Olympics
No full textArticle published with author as Billur Aslan not Billur Ozgul
Drug Delivered Poly(ethylene glycol) Diacrylate (PEGDA) Hydrogels and Their Mechanical Characterization Tests for Tissue Engineering Applications
No full textNormal operating range of the microbial community under potato
No full textOm de invloed van verschillende aardappelrassen op de bodem te meten bepaalde promovenda Özgül Inceoglu de variatie in parameters van de totale microbiële populatie in de bodem onder invloed van een aantal verschillende aardappelrassen. Ook woog zij de mogelijke effecten af van het zogeheten GM-ras tegen die van geselecteerde rassen.
Populaties van micro-organismen worden onder andere beïnvloed door plantenwortels. Dit gebeurt via de organische stoffen die in het door de wortels uitgescheiden exudaat zitten. Op deze manier trekken planten micro-organismen aan, die de door de plant uitgescheiden stoffen consumeren. Omdat verschillende plantensoorten en verschillende groeistadia van de plant leiden tot andere samenstellingen van wortelexudaten, is het logisch dat dit verschil ook tot uiting komt in de samenstelling van de microbiële populaties. Het is echter nog niet bekend in hoeverre zulke veranderingen voorkomen, hoe de dynamiek hiervan is en hoe deze veranderingen het functioneren van het systeem beïnvloeden. Als de invloed op de bodem van genetisch gemodificeerde planten bepaald moet worden, is het dus belangrijk om eerst de samenstelling van de microbiële populatie te bepalen, zowel als de individuele microbiële populaties en fluctuaties hierin. Hiervoor is het belangrijk, dat er eenvoudige methoden voorhanden zijn voor het monitoren van microbiële populaties en veranderingen in de tijd. Deze data vormen dan de basis voor de populatie onder landbouwgewassen in een bepaalde bodem, waaraan vervolgens de data van genetisch gemodificeerde planten gerelateerd kunnen worden, in dit geval voor de aardappel.
Soil-borne microbial communities are influenced by plant roots due to, among other factors, the excretion of organic compounds in the exudates. Plants thus selectively attract
microorganisms in their rhizospheres which then consume particular excreted compounds. It clearly follows that microbial communities in the rhizosphere may be differentially influenced by plant genotype as well as developmental stage if these incur different patterns of root
exudation. However, there is a paucity of knowledge on the extent to which such community shifts may occur, on the dynamics of the changes and on the putative effects regarding the functioning of the system. Hence, in order to weigh effects of transgenic plants, it is important to first assess the overall community composition as well as individual microbial populations as these are affected by plants, and study fluctuations therein. Moreover, easy monitoring methods are needed to track the community and diversity changes over time. Such assessments will define the baseline of cropping in a particular soil, against which the effect of genetically modified cultivars can be weighed, in this study tuned to potato as a crop.
So far, such a baseline of soil functioning has not been well-defined, and this is mainly due to the fact that soil ecosystems are dynamic and can be instantly changed due to seasonal influences as well as to different agricultural management practices. Thus, as this represents the normal operating conditions of the system, the seasonal variability of the soil communities under cropping regimes should be used to establish a baseline. The borders of these microbial
aspects will be provided by the extremes of fluctuations and thus determine the normal operating conditions. This will culminate in the provision of a technically-based protocol for
risk assessment of GM crops in terms of effects on soil.
Since less than 1% of soil microorganisms can be cultivated from their natural environments, new and more sensitive approaches are required that provide better measures
of community structure and function. However, biases of other nature are possibly introduced right at the forefront of most of our current soil DNA-based molecular analyses, that is, at the soil DNA extraction stage. Therefore in Chapter 2 of this thesis, four different DNA extraction methods, including two non-commercial ones, the Smalla et al and CIAT methods, and two commercial ones (MoBio Ultraclean and Powersoil), were compared for their efficiencies in
producing DNA from three agricultural soils of contrasting texture and organic matter content.
The analyses performed included assessments of DNA quality and quantity as well as PCRDGGE based analyses of bacterial, archaeal, ß-proteobacterial, ß-proteobacterial ammonium oxidizer, and pseudomonad and actinobacterial communities. Across the target bacterial groups, clear effects of DNA extraction method on the apparent richness and community structures based on DGGE patterns were discernible. Thus, different DNA extraction methods
applied to the same soil sample yield different views of the communities present in that sample. Powersoil was used for the rest of project, because of its efficiency, yield and purity.
In Chapter 3, the effects of plant cultivar, growth stage and soil type on the communities associated with the potato cultivars Aveka, Aventra, Karnico, Modena, Premiere
and Désirée were assessed in two different sandy fields, containing either high or low amounts of organic compounds in the different growth stages (young plant, flowering, senescence).
A rare case of tracheal lymphoma presenting with severe tracheal stenosis [«Un raro caso di linfoma della trachea con stenosi severa»]
No full textPrimary malignant lymphoma of the trachea is rare and its underlying mechanism remains unknown. Primary tracheal tumors are also very rare causes of airway obstructions. This case report features a 60 year-old woman who presented with the complaint of dyspnea. A mass narrowing the tracheal lumen posteriorly in the subglottic area and mediastinal lymphadenopathy was detected by computed tomography scan and a rijit bronchoscopy was performed. This showed polypoid, variable-sized, irregular nodules causing narrowing of the tracheal lumen over a 3 cm segment in the middle part of the trachea and a mass protruding into the tracheal lumen from the posterior part of the proximal trachea. Multiple biopsy was carried out from the nodules and the airway obstruction was treated with Argon Plasma Coagulation (APC). After removal of the debris, tracheal lumen patency was obtained. The histopathology examination revealed a small lymphocytic primary non-Hodgkin’s lymphoma of the trachea. To our knowledge, this is the first case of small lymphocytic primary tracheal lymphoma in the literature. © Mattioli 1885
Validity and reliability of the Turkish Patient-Rated Wrist Evaluation questionnaire
No full textObjective: The Patient-Rated Wrist Evaluation (PRWE) scale is a self-administered outcome questionnaire used to determine level of pain and disability in wrist problems. The scale includes pain (PRWE-P) and function (PRWE-F) subscales, the latter consisting of specific function (PRWE-SF) and usual (PRWE-UF) function. This study aimed to evaluate the validity and reliability of the Turkish version of the PRWE scale. Methods: Permission was sought and received from the original author of the PRWE for a Turkish translation for use in the study. The study included 110 patients (85 female and 25 male; mean age: 50.8 +/- 1.53 years; range: 18 to 85) with distal radius fracture, carpal tunnel syndrome, wrist ganglion cyst, De Quervain syndrome, Kienbock disease, and connective lesions affecting the wrist, all of whom completed the Turkish version of both the PRWE (PRWE-T) and the Disabilities of the Arm Shoulder and Hand scale (DASH). Reliability and validity of the PRWE-T scale were evaluated via an internal consistency analysis and a factor analysis respectively. The level of correlation between PRWE-T and DASH scores was also examined. Results: Cronbach's alpha coefficient was calculated as 0.86, 0.82 and 0.88 for PRWE-P, PRWE-F and PRWE-T respectively for the scale and all subscales. The PRWE-T scale was found to be highly reliable. A statistically significant correlation was found between PRWE-T and DASH in the criterion-related validity analysis (Spearman's rho=0.9). Conclusion: The PRWE-T was found to be valid and reliable. It is therefore suggested for use in evaluating patient-based pain and disability levels in routine clinical practice
The relation between cervical and thoracal disc herniations and multiple sclerosis plaques: a retrospective review
No full textThe aim of the study is the evaluation cervical and thoracal disc herniations are predisposant factor to the formation and activation of plaques formation of relapsing remitting (R-R ) type multiple sclerosis (MS) patients. We performed a retrospective study on R-R type MS diagnosed patients who also had cervical and thoracal disc herniations. 185 cervical and 136 thoracic in total 321 MR images of 104 (42 men, 62 women) MS patients with R-R type were evaluated retrogradly. When we evaluate the association between cervical or thoracal disc herniation and MS plaques we determined the same localization of cervical herniation and MS plaques was statistically significant. In conclusion, cervical and thoracic disc herniations may contribute to distrupion of blood brain barrier by generating microtraumas and this may lead to MS plaque formation. Therefore, early and effective treatment of MS patients having disc compression is crucial for preventing from sequels and for providing a better life quality. [Med-Science 2017; 6(4.000): 643-645
Student EFL Teachers⿿ Receptive Vocabulary Size
No full textAbstractThis study reports the results of a study investigating the receptive vocabulary size of student EFL teachers. The study also examined the relationship between the participants⿿ academic achievement (departmental GPA) and their receptive vocabulary size and the existence of any gender-related difference. The study was carried out in English Language Teaching (ELT) Department of a major state university in Turkey. A total of 104 undergraduate students (females: 76 and males: 28) enrolled in the department voluntarily participated in the study, took the Version 2 of the Vocabulary Levels Tests (Schmitt, Schmitt & Clapham, 2001) and responded to a survey investigating their GPA scores and genders. The results revealed that student EFL teachers have a high level of total receptive vocabulary capacity size in their foreign language (M=103.82). Learners⿿ academic achievement (GPA) is treated as an indicator of their language proficiency level in many studies of English Language Teaching (ELT) field. However, the results of this study revealed that there was not any statistically significant correlation between academic achievement (GPA) and their receptive vocabulary size. Although GPA may be a sign of academic achievement (GPA) and successful studentship, it may not readily one's actual English language proficiency. The results also indicated that there was no significant difference between males and females regarding their receptive vocabulary size
