Search results for: contrast masking

Authors: M. Zeitoun, K. Abdallah, M. Rashwan

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Introduction: A growing body of evidence indicates that apelin, a relatively recent member of the adipokines family, has a potential anti-atherogenic effect. An association between low serum apelin state and coronary artery disease (CAD) was previously reported; however, the relationship between apelin and the atherosclerotic burden was unclear. Objectives: Our aim was to explore the correlation of serum apelin level with coronary calcium score (CCS) as a quantitative marker of coronary atherosclerosis. Methods: This observational cross-sectional study enrolled 100 consecutive subjects referred for cardiac multi-detector computed tomography (MDCT) for assessment of CAD (mean age 54 ± 9.7 years, 51 male and 49 females). Clinical parameters, glycemic and lipid profile, high sensitivity CRP (hsCRP), homeostasis model assessment of insulin resistance (HOMA-IR), serum creatinine and complete blood count were assessed. Serum apelin levels were determined using a commercially available Enzyme Immunoassay (EIA) Kit. High-resolution non-contrast CT images were acquired by a 64-raw MDCT and CCS was calculated using the Agatston scoring method. Results: Forty-three percent of the studied subjects had positive coronary artery calcification (CAC). The mean CCS was 79 ± 196.5 Agatston units. Subjects with detectable CAC had significantly higher fasting plasma glucose, HbA1c, and WBCs count than subjects without detectable CAC (p < 0.05). Most importantly, subjects with detectable CAC had significantly lower serum apelin level than subjects without CAC (1.3 ± 0.4 ng/ml vs. 2.8 ± 0.6 ng/ml, p < 0.001). In addition, there was a statistically significant inverse correlation between serum apelin levels and CCS (r = 0.591, p < 0.001); on multivariate analysis this correlation was found to be independent of traditional cardiovascular risk factors and hs-CRP. Conclusion:To the best of our knowledge, this is the first report of an independent association between apelin and CCS in patients with suspected CAD. Apelin emerges as a possible novel biomarker for CAD, but this result remains to be proved prospectively.

Keywords: HbA1c, apelin, adipokines, coronary calcium score (CCS), coronary artery disease (CAD)

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Authors: Ramin Ghasemi Shayan, Morteza Janebifam

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Tumors are regularly inhomogeneous. Provincial varieties in death, metabolic action, multiplication and body part are watched. There’s expanding proof that strong tumors may contain subpopulations of cells with various genotypes and phenotypes. These unmistakable populaces of malignancy cells can connect during a serious way and may contrast in affectability to medications. Most tumors show organic heterogeneity1–3 remembering heterogeneity for genomic subtypes, varieties inside the statement of development variables and genius, and hostile to angiogenic factors4–9 and varieties inside the tumoural microenvironment. These can present as contrasts between tumors in a few people. for instance, O6-methylguanine-DNA methyltransferase, a DNA fix compound, is hushed by methylation of the quality advertiser in half of glioblastoma (GBM), adding to chemosensitivity, and improved endurance. From the outset, there includes been specific enthusiasm inside the usage of dissemination weighted imaging (DWI) and dynamic complexity upgraded MRI (DCE-MRI). DWI sharpens MRI to water dispersion inside the extravascular extracellular space (EES) and is wiped out with the size and setup of the cell populace. Additionally, DCE-MRI utilizes dynamic obtaining of pictures during and after the infusion of intravenous complexity operator. Signal changes are additionally changed to outright grouping of differentiation permitting examination utilizing pharmacokinetic models. PET scan modality gives one of a kind natural particularity, permitting dynamic or static imaging of organic atoms marked with positron emanating isotopes (for example, 15O, 18F, 11C). The strategy is explained to a colossal radiation portion, which points of confinement rehashed estimations, particularly when utilized together with PC tomography (CT). At long last, it's of incredible enthusiasm to quantify territorial hemoglobin state, which could be joined with DCE-CT vascular physiology estimation to create significant experiences for understanding tumor hypoxia.

Keywords: heterogeneity, computerized tomography scan, magnetic resonance imaging, PET

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Authors: Thiago Spilborghs Bueno Meyer, Plinio Thomaz Aquino Junior

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Through speech, which privileges the functional and interactive nature of the text, it is possible to ascertain the spatiotemporal circumstances, the conditions of production and reception of the discourse, the explicit purposes such as informing, explaining, convincing, etc. These conditions allow bringing the interaction between humans closer to the human-robot interaction, making it natural and sensitive to information. However, it is not enough to understand what is said; it is necessary to recognize emotions for the desired interaction. The validity of the use of neural networks for feature selection and emotion recognition was verified. For this purpose, it is proposed the use of neural networks and comparison of models, such as recurrent neural networks and deep neural networks, in order to carry out the classification of emotions through speech signals to verify the quality of recognition. It is expected to enable the implementation of robots in a domestic environment, such as the HERA robot from the RoboFEI@Home team, which focuses on autonomous service robots for the domestic environment. Tests were performed using only the Mel-Frequency Cepstral Coefficients, as well as tests with several characteristics of Delta-MFCC, spectral contrast, and the Mel spectrogram. To carry out the training, validation and testing of the neural networks, the eNTERFACE’05 database was used, which has 42 speakers from 14 different nationalities speaking the English language. The data from the chosen database are videos that, for use in neural networks, were converted into audios. It was found as a result, a classification of 51,969% of correct answers when using the deep neural network, when the use of the recurrent neural network was verified, with the classification with accuracy equal to 44.09%. The results are more accurate when only the Mel-Frequency Cepstral Coefficients are used for the classification, using the classifier with the deep neural network, and in only one case, it is possible to observe a greater accuracy by the recurrent neural network, which occurs in the use of various features and setting 73 for batch size and 100 training epochs.

Keywords: emotion recognition, speech, deep learning, human-robot interaction, neural networks

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Authors: Angelis P. Barlampas

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Purpose of Learning Objective: This case depicts the need for cooperation between the emergency department and the radiologist to achieve the best diagnostic result for the patient. The clinical picture must correlate well with the radiology report and when it does not, this is not necessarily someone’s fault. Careful interpretation and good knowledge of the limitations, advantages and disadvantages of each imaging procedure are essential for the final diagnostic goal. Methods or Background: A patient was brought to the emergency department by their relatives. He was suddenly confused and his mental status was altered. He hadn't any history of mental illness and was otherwise healthy. A computing tomography scan without contrast was done, but it was unremarkable. Because of high clinical suspicion of probable neurologic disease, he was admitted to the hospital. Results or Findings: Another T was done after 48 hours. It showed a hypodense region in both thalamic areas. Taking into account that the first CT was normal, but the initial clinical picture of the patient was alerting of something wrong, the repetitive CT exam is highly suggestive of a probable diagnosis of bilateral thalamic infractions. Differential diagnosis: Primary bilateral thalamic glioma, Wernicke encephalopathy, osmotic myelinolysis, Fabry disease, Wilson disease, Leigh disease, West Nile encephalitis, Greutzfeldt Jacob disease, top of the basilar syndrome, deep venous thrombosis, mild to moderate cerebral hypotension, posterior reversible encephalopathy syndrome, Neurofibromatosis type 1. Conclusion: As is the case of limitations for any imaging procedure, the same applies to CT. The acute ischemic attack can not depict on CT. A period of 24 to 48 hours has to elapse before any abnormality can be seen. So, despite the fact that there are no obvious findings of an ischemic episode, like paresis or imiparesis, one must be careful not to attribute the patient’s clinical signs to other conditions, such as toxic effects, metabolic disorders, psychiatric symptoms, etc. Further investigation with MRI or at least a repeated CT must be done.

Keywords: CNS, CT, thalamus, emergency department

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Authors: Chingwen Yeh, I. Chen Huang

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This paper aims to conduct a case study on kinesthetic intelligence development intervention with a child who has Asperger symptom identified by physician. First, the characteristics of Asperger were defined based on the related literature. Some Asperger's people are born with outstanding insight and are good at solving complex and difficult problems. In contrast to high-functioning autistic, Asperger children do not lose their ability to express themselves verbally. However in the cognitive function, they focus mainly on the things they are interested in instead of paying attention to the whole surrounding situation. Thus it is difficult for them not only to focus on things that they are not interesting in, but also to interact with people. Secondly, 8-weeks of kinesthetic intelligence development courses were designed within a series of physical action that including the following sections: limbs coordination, various parts of body rhythm changes, strength and space awareness and breathing practice. In classroom observations were recorded both on words and with video as the qualitative research data. Finally, in-depth interview with the case child’s teachers, parents and other in class observers were documented on a weekly base in order to examine the effectiveness of before and after the kinesthetic intelligence development course and to testify the usefulness of the lesson plan. This research found that the case child has improved significantly in terms of attention span and body movement creativity. In the beginning of intervention, the case child made less eyes contact with others. The instructor needed to face the case child to confirm the eyes contact. And the instructor also used various adjective words as guiding language for all kinds of movement sequence practice. The result can cause the case child’s attention and learning motivation. And the case child understand what to do to enhance kinesthetic intelligence. These authors hope findings of this study can contribute as reference for the further research on the related topic.

Keywords: asperger symptom, body rhythm, kinesthetic intelligence, space awareness

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Authors: Florence Malongane, Lyndy J. McGaw, Legesse K. Debusho, Fhatuwani N. Mudau

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Rooibos (Aspalathus linearis (Burm.f.) R.Dahlgren), honeybush (Cyclopia Vent. species), bush tea (Athrixia phylicoides DC.) and special tea (Monsonia burkeana) are traditionally consumed herbal teas in South Africa. The volatile and sensory qualities of rooibos and honeybush tea have previously been described although there is a dearth of information regarding the sensory attributes and volatile compounds analysis of special tea and bush tea. The objective of this study was to describe the sensory properties, compare the differences in descriptive sensory analysis (DSA) and volatile compounds of bush tea, special, rooibos, honeybush and the blend of bush tea with special, honeybush and rooibos in a 1:1 ratio and subsequently to determine the influence of blending bush tea with other herbal teas. DSA was used to assess the sensory attributes of the teas while gas chromatography–mass spectrometry (GC-MS) was used to quantitatively determine the volatile components of the teas. Rooibos tea and honeybush tea had an overall sweet-caramel, honey-sweet, perfume floral and woody aroma with slight astringency, consistent with the taste and aftertaste attributes. In contrast, bush tea and special tea depicted green-cut grass, dry green herbal, cooked spinach aroma as well as taste and aftertaste characteristics. GC-MS analyses revealed that the seven tea samples had similar major volatiles, including 2-furanmethanol, 2-methoxy-4-vinylphenol, acetic acid, D-limonene terpene and phytol. Cluster analysis revealed that the sweet and woody flavour of honeybush and rooibos were ascribed to the presence of á-myrcene, phenylethyl alcohol, phytol and vanillin. The bitter, medicinal flavour attributes of special tea were attributed to (-)-carvone. Blending of bush tea with rooibos and honeybush tea toned down its aversive flavour components, typically the bitter, green-cut grass and herbal properties, thus minimising the possibility of consumer aversion.

Keywords: bush tea, rooibos tea, honeybush tea, sensory, volatile compounds

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Authors: Shashank Kumar, Mansi Chandra, Ujjawal Singh, Parth Gupta, Rishi Ram, Arnab Sarkar

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Milk is one of the basic and primary sources of food and energy as we start consuming milk from birth. Hence, milk quality and purity and checking the concentration of its constituents become necessary steps. Considering the importance of the purity of milk for human health, the following study has been carried out to simultaneously detect and quantify the different adulterants like urea and starch in milk with the help of a paper-based microfluidic device integrated with a smartphone. The detection of the concentration of urea and starch is based on the principle of colorimetry. In contrast, the fluid flow in the device is based on the capillary action of porous media. The microfluidic channel proposed in the study is equipped with a specialized detection zone, and it employs a colorimetric indicator undergoing a visible color change when the milk gets in touch or reacts with a set of reagents which confirms the presence of different adulterants in the milk. In our proposed work, we have used iodine to detect the percentage of starch in the milk, whereas, in the case of urea, we have used the p-DMAB. A direct correlation has been found between the color change intensity and the concentration of adulterants. A calibration curve was constructed to find color intensity and subsequent starch and urea concentration. The device has low-cost production and easy disposability, which make it highly suitable for widespread adoption, especially in resource-constrained settings. Moreover, a smartphone application has been developed to detect, capture, and analyze the change in color intensity due to the presence of adulterants in the milk. The low-cost nature of the smartphone-integrated paper-based sensor, coupled with its integration with smartphones, makes it an attractive solution for widespread use. They are affordable, simple to use, and do not require specialized training, making them ideal tools for regulatory bodies and concerned consumers.

Keywords: paper based microfluidic device, milk adulteration, urea detection, starch detection, smartphone application

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Authors: Liat Kulik

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The main goal of the present study was to examine gender differences in the variables that explain the experience of role conflict and well-being among Jewish working fathers and mothers in the Israel. The experience of work-family conflict arises from simultaneous pressures from the work and family domains that are mutually incompatible. In light of the expansion of women's role set following the addition of paid employment outside of the home, most of the studies dealing with the impact of multiple roles on well-being have been conducted among women. However, changes in gender roles in recent years have also affected men's role set, as reflected in the terms ‘new men’ and ‘new fathers’. Based on structural equation modeling, the study examined gender differences in variables that explain the experience of two types of role conflict – family interferes with work (FIW) and work interferes with family (WIF), as well as with the sense of well-being (positive and negative affect) among 611 employed Jewish mothers and fathers in Israel. The findings revealed that for women, both FIW and WIF conflict correlated negatively with well-being, whereas for men, a negative correlation with well-being was found only in the case of FIW conflict. For both men and women, egalitarian gender role ideology correlated with the dimension of positive effect, but the correlation was stronger for men. The findings highlight the contribution of egalitarian gender role ideology to alleviating the experience of role conflict and improving the emotional well-being of both men and women. Contrary to expectations, social support contributed more to mitigating negative effect among men than women. On the whole, the findings highlight the changes that men have experienced in the work-family system. In sum, the research findings shed new light on the masculine image in terms of the experience of FIW conflict. In contrast to the prevailing assumption that FIW role conflict is predominant among women, the findings of this study indicate that today, this type of role conflict is experienced equally by men and women whereas WIF conflict is predominant among men. Furthermore, contrary to expectations, levels of perceived social support were found to be similar for men and women, and men benefited from it even more than women did.

Keywords: FIW conflict, WIF conflict, social support, egalitarian gender role ideology, overload

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Authors: Natascha Reich

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In colonial Peru, the Spanish crown relied on religious orders, most notably Dominicans, Franciscans, and Jesuits, for accelerating processes of colonization. The dissemination of Christian art, architecture, and music, and most of all, the agency of indigenous people in their production played a key role in facilitating the acceptance of the new religious and political system. Current research on Peruvian colonial music culture and its role as a vehicle for colonization focus on practices in urban centers. The lack of (written) primary sources seems to turn rural areas into a less attractive research territory for musicologists. This paper advocates for a more inclusive approach. By investigating seventeenth-century pipe organs as material remains of Franciscan missionary music culture, it shows how reactions to colonial forces and Christianization in rural Andean locations could follow tendencies different from those in urban areas. Indigenous musicians in cities tried to 'fit' into the European system in order to be accepted by the ruling Spanish elite. By contrast, the indigenous-built pipe organs in the rural Peruvian Colca-Valley show distinctly native-Andean influences. This paper argues that this syncretism can be interpreted as hybridity in Homi K. Bhabha’s sense, as a means of the colonized to undermine the power of the colonizer and to advance reactionary politics. Not only will it show the necessity of considering rural Peruvian music history in modern scholarship for arriving at a more complete picture of colonial culture, but it will also evidence the advantages of a mixed-methodology approach. Historical organology, combined with concepts from ethnomusicology and post-colonial studies, proves as a useful tool in the absence or scarcity of written primary sources.

Keywords: cultural hybridity, music as reactionary politics, Latin American pipe organs, Peruvian colonial music

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Authors: Ji-Won Park, Jong-Wha Kim

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Triploid L. lancifolium have a wide geographic distribution. By contrast, diploid L. lancifolium have limited distributions in the islands and coastal regions of the South and West Korean Peninsula and northern Tsushima Island, Japan. L. lancifolium diploids and triploids are not sympatrically distributed with other lily species or ploidy lines in West Sea and South Sea Islands of the Korean Peninsula. This observation raises the following questions: 'Why have autotriploid L. lancifolium never been observed in those isolated islands?', 'What mechanism excludes the occurrence of autotriploids, if they arise?'. To determine the occurrence and survival of triploid plants in natural diploid populations of tiger lily (Lilium lancifolium), ploidy analysis was conducted on natural open-pollinated seeds produced from plants grown on isolated islands, and on hybrid seeds produced by artificial crossing between plant populations originating on different Korean islands. Normal seeds were classified into five grades depending on the ratio of embryo/endosperm lengths, including 5/5, 4/5, 3/5, 2/5, and 1/5. Triploids were not observed among seedlings produced from natural open pollinations on isolated islands. Triploids were detected only in seedlings of underdeveloped seed grades(3/5 and 2/5) from artificial crosses between populations from different isolated islands. The triploid occurrence frequency was calculated as 0.0 for natural open-pollinated seedlings and 0.000582 for artificial crosses(6 triploids from 10,303 seedlings). Triploids were produced from crosses between isolated populations located at least 70 km apart; no triploids were detected in inter-population crosses of plants originating on the same islands. Triploid seedlings have very low viability in soil. We analyzed factors affecting triploid occurrence and survival in natural diploid populations of L. lancifolium. The results suggest that triploids originate from fertilization between plants that are genetically isolated due to geographical isolation and/or genotypic differences.

Keywords: Lilium lancifolium, autotriploid, natural population, genetic distance, 2n female gamete

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Authors: Vera Sovkova, Andrea Mickova, Matej Buzgo, Karolina Vocetkova, Eva Filova, Evzen Amler

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PCL (poly-ε-caprolactone) nanofibrous scaffolds with adhered liposomes were prepared and tested as a possible drug delivery system for various synthetic growth factors. TGFβ, bFGF, and IGF-I have been shown to increase hMSC (human mesenchymal stem cells) proliferation and to induce hMSC differentiation. Functionalized PCL nanofibers were prepared with synthetic growth factors encapsulated in liposomes adhered to them in three different concentrations. Other samples contained PCL nanofibers with adhered, free synthetic growth factors. The synthetic growth factors free medium served as a control. The interaction of liposomes with the PCL nanofibers was visualized by SEM, and the release kinetics were determined by ELISA testing. The potential of liposomes, immobilized on the biodegradable scaffolds, as a delivery system for synthetic growth factors, and as a suitable system for MSCs adhesion, proliferation and differentiation in vitro was evaluated by MTS assay, dsDNA amount determination, confocal microscopy, flow cytometry and real-time PCR. The results showed that the growth factors adhered to the PCL nanofibers stimulated cell proliferation mainly up to day 11 and that subsequently their effect was lower. By contrast, the release of the lowest concentration of growth factors from liposomes resulted in gradual proliferation of MSCs throughout the experiment. Moreover, liposomes, as well as free growth factors, stimulated type II collagen production, which was confirmed by immunohistochemical staining using monoclonal antibody against type II collagen. The results of this study indicate that growth factors enriched liposomes adhered to surface of PCL nanofibers could be useful as a drug delivery instrument for application in short timescales, be combined with nanofiber scaffolds to promote local and persistent delivery while mimicking the local microenvironment. This work was supported by project LO1508 from the Ministry of Education, Youth and Sports of the Czech Republic

Keywords: drug delivery, growth factors, hMSC, liposomes, nanofibres

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Authors: Ghorbeli Eya, Naija Lamia, Khessairi Nayssem, Saadallah Fatma, Slimane Maher, Tarek Ben Dhiab

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INTRODUCTION: Borderline ovarian tumors account for 15 to 20% of ovarian tumors. Prognostic factors of recurrence include the stage of the disease, presence of peritoneal implants, micropapillary pattern, microinvasion and intra-epithelial carcinoma. Fertility sparing constitutes a major therapeutic issue in young patients that leads to conservative surgical treatment in specific cases. METHODS: We conducted a retrospective descriptive study including patients treated at the Salah Azaiez Institute for Borderline Ovarian Tumor who underwent conservative surgical treatment from 2003 to 2018. RESULTS: Nine patients were included in our study. The median age was 33 years. Three patients were nulliparous. Given the age, conservative treatment was indicated in all these patients. Cystectomy without ovariectomy was indicated in 5 of the 9 women, which was within the margin of tumor resection on definitive anatomopathic examination in 3 of the 5 women. In contrast, given the impossibility of ovarian conservation, total annexectomy was carried out in 4 of all these women. All of the patients were followed regularly postoperatively; three had a carcinomatous transformation as an ovarian adenocarcinoma at an average interval of 18 months. Among these three patients, a single one presented intra-peritoneal metastases, requiring radical surgical treatment and adjuvant chemotherapy with 6 cures of Carbo-Taxol, with a good tolerance and a complete response. Moreover, one patient had a recurrence on the contralateral ovary as a Borderline mucinous ovarian tumor. For the remaining four women, after a median follow-up of 35 months, one patient fell spontaneously pregnant during follow-up, and three patients were in complete remission at 16 months. CONCLUSION: Borderline tumors of the ovary usually occur in young patients, which makes conservative treatment advisable if possible, but this always comes with a risk of recurrence and/or carcinomatous transformation, especially if the conservative surgical procedure was a cystectomy instead of a total annexectomy, and even more so if the resection margins were tumoral.

Keywords: ovarian tumor, conservative treatment, surgical management, borderline ovarian tumor, recurrence management

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Authors: D. Anderlini, G. Wallis

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Background: The number of people experiencing stroke is steadily increasing due to changes in diet and lifestyle, to longer life expectancy resulting in older population, to higher survival rates as a consequence of improvements during the acute phase. This study considers what risk factors might contribute to delayed entry to hospital for treatment. Methods: We analyzed data from 2472 patients admitted to the Stroke Unit of the Royal Brisbane Women's Hospital, Australia, between 2002 to 2011. Results: Previous studies have reported that factors which can contribute to delay include the patient’s age, the time of day, physical location, visit the GP instead of going to the emergency, means of transport, severity of symptoms and type of stroke. Contrary to findings of other studies, we found a strong correlation between side of lesion and delay in admission: patients with right hemisphere lesions had an average delay of 3.78 days, while patients with left hemisphere lesions had an average delay of 1.49 days. Damage to the right hemisphere generally ends in motor impairment in the non-dominant hand and no speech impediment. In contrast, left hemisphere lesions can result in deficit to; dominant hand function and aphasia which will be noticed even if their impact on performance is relatively minor. A finding which goes against many previous studies, is the fact that women get to the hospital much sooner than men, showing an average delay of 0.92 days in women vs. 3.36 days in men. Conclusion: Acute surgical-pharmacological therapies are most effective if applied immediately after stroke. Hence delays to admission can be crucial to the degree of recovery. The tendency of patients to overlook symptoms of right hemisphere lesion should be the target of information campaigns both for the general public and GPs. Why do men go to hospital so late? We don't know yet! Nevertheless an awareness plan specifically direct to male population should be on the agenda of Health Departments.

Keywords: gender, admission delay, stroke location, bioinformatics, biomedicine

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Authors: Mei Teng Woo, Keith Davids, Jarmo Liukkonen, Jia Yi Chow, Timo Jaakkola

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Wearable garments such as tapes, compression garments, and braces could improve proprioception and reduced postural sway. The aim of this study was to examine the effects of wearable garments on postural regulation in a sample of community-dwelling elderly individuals, aged 65 years. It was hypothesized that wearable garments such as socks would provide stimulation to lower leg mechanoreceptors, and help participants achieve better postural regulation. Participants (N=63) performed a 30-s Romberg balance test protocol under four conditions (barefoot; wearing commercial socks; wearing clinical compression socks; wearing non-clinical compression socks), in a counterbalanced order, with four levels of performance difficulty: (1) standing on a stable surface with open eyes (SO); (2) a stable surface with closed eyes (SC); (3) a foam surface with open eyes (FO); and (4) a foam surface with closed eyes (FC). Centre of pressure (CoP) measurements included postural sway area (C90 area), trace length (TL) and sway velocity. Thirty-five participants (55.6%) showed positive effects of wearing the socks (responded group). In the responded group, it was revealed that socks showed significant differences in SO, SC and FO conditions for the two CoP measurements - TL and sway velocity (p < 0.05). In contrast, in the non-responded group, barefoot condition significantly decreased the TL and velocity in the SO condition. From the positive effects observed in the responded group, it is possible that wearable garments provide sensory cues that could interact with a biological cueing system to enhance performance in the postural regulation system. This study suggests that individuals respond to the socks treatments differently and future research should be undertaken to examine the factors that benefited the responded group of participants.

Keywords: community-dwelling, elderly adults, postural regulation, wearable garments

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Authors: M. Varmaziar

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Magnesium (Mg) is an essential mineral that plays a crucial role in the human body. Certain types of foods, including nuts, grains, fruits, vegetables, and whole grains, are rich sources of magnesium. Mg serves as an essential cofactor for numerous enzymatic reactions, including energy metabolism, cellular growth, glycolysis, and protein synthesis. The Mg-ATP complex serves as an energy source and is vital for many physiological functions, including nerve conduction, muscle contraction, and blood pressure regulation. Despite the vital role of magnesium in energy metabolism, maintaining adequate magnesium intake is often overlooked among the general population and athletes. The aim of this study was to investigate the effect of magnesium supplementation on the physical activities of field athletes. Field athletes were divided into two groups: those who consumed magnesium supplements and those who received a placebo. These two groups received either 500 mg of magnesium oxide or a placebo daily for 8 weeks. At the beginning and end of the study, athletes completed ISI questionnaires and physical activity assessments. Nutritional analyses were performed using N4 software, and statistical analyses were conducted using SPSS19 software. The results of this study revealed a significant difference between the two study groups. Athletes who received magnesium supplements experienced less fatigue related to field athletic activities and muscle soreness. In contrast, athletes who received the placebo reported more significant fatigue and muscle soreness. A concerning finding in these results is that the performance of athletic activities may be at risk with low magnesium levels. Therefore, magnesium is essential for maintaining health and plays a crucial role in athletic performance. Consuming a variety of magnesium-rich foods ensures that individuals receive an adequate amount of this essential nutrient in their diet. The consumption of these foods improves performance parameters in athletic exercises.

Keywords: athletic performance, effect, field athletes, magnesium supplement

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Authors: Naamane Remita, Mohammed laïd Mechri, Nouredine Zekri, Smaïl Chihi

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The goal of this study is the estimation real and imaginary components of both electrical impedance and permittivity z', z'' and ε', ε'' respectively, in Ouargla dunes sand at different temperatures and different frequencies, with alternating current (AC) equal to 1 volt, using the impedance spectroscopy (IS). This method is simple and non-destructive. the results can frequently be correlated with a number of physical properties, dielectric properties and the impacts of the composition on the electrical conductivity of solids. The experimental results revealed that the real part of impedance is higher at higher temperature in the lower frequency region and gradually decreases with increasing frequency. As for the high frequencies, all the values of the real part of the impedance were positive. But at low frequency the values of the imaginary part were positive at all temperatures except for 1200 degrees which were negative. As for the medium frequencies, the reactance values were negative at temperatures 25, 400, 200 and 600 degrees, and then became positive at the rest of the temperatures. At high frequencies of the order of MHz, the values of the imaginary part of the electrical impedance were in contrast to what we recorded for the middle frequencies. The results showed that the electrical permittivity decreases with increasing frequency, at low frequency we recorded permittivity values of 10+ 11, and at medium frequencies it was 10+ 07, while at high frequencies it was 10+ 02. The values of the real part of the electrical permittivity were taken large values at the temperatures of 200 and 600 degrees Celsius and at the lowest frequency, while the smallest value for the permittivity was recorded at the temperature of 400 degrees Celsius at the highest frequency. The results showed that there are large values of the imaginary part of the electrical permittivity at the lowest frequency and then it starts decreasing as the latter increases (the higher the frequency the lower the values of the imaginary part of the electrical permittivity). The character of electrical impedance variation indicated an opportunity to realize the polarization of Ouargla dunes sand and acquaintance if this compound consumes or produces energy. It’s also possible to know the satisfactory of equivalent electric circuit, whether it’s miles induction or capacitance.

Keywords: electrical impedance, electrical permittivity, temperature, impedance spectroscopy, dunes sand ouargla

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Authors: Zahra Ebrahimi, Abbas Moradan

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This study investigated the effect of applying different layers of activity for different Iranian intermediate EFL learner’s oral proficiency and two of its components (fluency and accura-cy) for the beneficial use of films within speaking classes. For this purpose, thirty Iranian EFL intermediate learners were selected based on availability sampling, they were divided into one experimental group and one control group, each consisting of 15 participants, who were proved to be homogeneous based on the results obtained from IELTS oral proficien-cy test prior to the treatment. Experimental Group received the treatment which was apply-ing different layers of speaking tasks according to learners’ level of fluency and accuracy. Control group received ordinal treatment of speaking classrooms. The materials for this study consisted of 11 English movies for each session, voice-recorder device, and IELTS oral proficiency tests as well as two interviews based on Ur’s oral scale for measuring fluen-cy and accuracy. The treatment was run for 12 sessions in six weeks. At the end of the treatment, all the students both in experimental and control group were given a post-test interview based on Ur’s scale. To compare and contrast the amount of progress of the learners in different groups the results of the pre-test and post-test of speaking were analysed by using T-tests. Moreover, Multivariate analysis of variance was also used to check the hypotheses. Results showed that application of different layers of activity with regard to students’ level, led to a significantly superior performance in experimental group. Thus, this study verified the positive effect of implementation of different layers of activity and tasks to achieve progress in speaking skill. It can also help to create a less stressful at-mosphere of learning in which all the students will be given specific time to speak and lead them to be autonomous learners.

Keywords: differentiated instruction, learners’ style, multiple intelligence, speaking skill, task-based activities

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Authors: Ada Yurman

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Using the case of Israeli Atomic Spy Mordechai Vanunu as an example, this study sought to examine social response to political deviance whereby social response can be mobilized in order to achieve social control. Mordechai Vanunu, a junior technician in the Dimona Atomic Research Center, played a normative role in the militaristic discourse while working in the “holy shrine” of the Israeli defense system for many years. At a certain stage, however, Vanunu decided to detach himself from this collective and launched an assault on this top-secret circle. Israeli society in general and the security establishment in particular found this attack intolerable and unforgivable. They presented Vanunu as a ticking time bomb, delegitimized him and portrayed him as “other”. In addition, Israeli enforcement authorities imposed myriad prohibitions and sanctions on Vanunu even after his release from prison – “as will be done to he who desecrates holiness.” Social response to Vanunu at the time of his capture and trial was studied by conducting a content analysis of six contemporary daily newspapers. The analysis focused on use of language and forms of expression. In contrast with traditional content analysis methodology, this study did not just look at frequency of expressions of ideas and terms in the text and covert content; rather, the text was analyzed as a structural whole, and included examination of style, tone and unusual use of imagery, and more, in order to uncover hidden messages within the text. The social response to this case was extraordinarily intense, not only because in this case of political deviance, involving espionage and treason, Vanunu’s actions comprised a real potential threat to the country, but also because of the threat his behavior posed to the symbolic universe of society. Therefore, the response to this instance of political deviance can be seen as being part of a mechanism of social control aiming to protect world view of society as a whole, as well as to punish the criminal.

Keywords: militarism, political deviance, social construction, social control

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Authors: Eric Jacob Bacon, Chaoyang Jin, Dianning He, Shuaishuai Hu, Lanbo Wang, Han Li, Shouliang Qi

Abstract:

Objective: Refractory epilepsy is a complicated type of epilepsy that can be difficult to diagnose. Recent technological advancements have made resting-state functional magnetic resonance (rsfMRI) a vital technique for studying brain activity. However, there is still much to learn about rsfMRI. Investigating rsfMRI connectivity may aid in the detection of abnormal activities. In this paper, we propose studying the functional connectivity of rsfMRI candidates to diagnose epilepsy. Methods: 45 rsfMRI candidates, comprising 26 with refractory epilepsy and 19 healthy controls, were enrolled in this study. A data-driven approach known as independent component analysis (ICA) was used to achieve our goal. First, rsfMRI data from both patients and healthy controls were analyzed using group ICA. The components that were obtained were then spatially sorted to find and select meaningful ones. A two-sample t-test was also used to identify abnormal networks in patients and healthy controls. Finally, based on the fractional amplitude of low-frequency fluctuations (fALFF), a chi-square statistic test was used to distinguish the network properties of the patient and healthy control groups. Results: The two-sample t-test analysis yielded abnormal in the default mode network, including the left superior temporal lobe and the left supramarginal. The right precuneus was found to be abnormal in the dorsal attention network. In addition, the frontal cortex showed an abnormal cluster in the medial temporal gyrus. In contrast, the temporal cortex showed an abnormal cluster in the right middle temporal gyrus and the right fronto-operculum gyrus. Finally, the chi-square statistic test was significant, producing a p-value of 0.001 for the analysis. Conclusion: This study offers evidence that investigating rsfMRI connectivity provides an excellent diagnosis option for refractory epilepsy.

Keywords: ICA, RSN, refractory epilepsy, rsfMRI

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Authors: Anita Lazurko, Laszlo Pinter, Jeremy Richardson

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Uncertain climate projections, multiple possible development futures, and a financing gap create challenges for water infrastructure decision making. In contrast to conventional predict-plan-act methods, an emerging decision paradigm that enables social-ecological resilience supports decisions that are appropriate for uncertainty and leverage social, ecological, and economic multifunctionality. Concurrently, water infrastructure project finance plays a powerful role in sustainable infrastructure development but remains disconnected from discourse in socio-ecological resilience. At the time of research, a project to transfer water from Lesotho to Botswana through South Africa in the Orange-Senqu River Basin was at the pre-feasibility stage. This case was analysed through documents and interviews to investigate how uncertainty and multifunctionality are conceptualised and considered in decisions for the resilience of water infrastructure and to explore bridging concepts that might allow project finance to better enable socio-ecological resilience. Interviewees conceptualised uncertainty as risk, ambiguity and ignorance, and multifunctionality as politically-motivated shared benefits. Numerous efforts to adopt emerging decision methods that consider these terms were in use but required compromises to accommodate the persistent, conventional decision paradigm, though a range of future opportunities was identified. Bridging these findings to finance revealed opportunities to consider a more comprehensive scope of risk, to leverage risk mitigation measures, to diffuse risks and benefits over space, time and to diverse actor groups, and to clarify roles to achieve multiple objectives for resilience. In addition to insights into how multiple decision paradigms interact in real-world decision contexts, the research highlights untapped potential at the juncture between socio-ecological resilience and project finance.

Keywords: socio-ecological resilience, finance, multifunctionality, uncertainty

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Authors: B. J. Babalola, M. B. Shongwe

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Spark Plasma Sintering technique is a novel processing method that produces limited grain growth and highly dense variety of materials; alloys, superalloys, and carbides just to mention a few. However, initial particle size and spark plasma sintering parameters are factors which influence the grain growth and mechanical properties of sintered materials. Ni-Cr alloys are regarded as the most promising alloys for aerospace turbine blades, owing to the fact that they meet the basic requirements of desirable mechanical strength at high temperatures and good resistance to oxidation. The conventional method of producing this alloy often results in excessive grain growth and porosity levels that are detrimental to its mechanical properties. The effect of sintering temperature was evaluated on the microstructure and mechanical properties of the nanostructured Ni-17Cr alloy. Nickel and chromium powder were milled using high energy ball milling independently for 30 hours, milling speed of 400 revs/min and ball to powder ratio (BPR) of 10:1. The milled powders were mixed in the composition of Nickel having 83 wt % and chromium, 17 wt %. This was sintered at varied temperatures from 800°C, 900°C, 1000°C, 1100°C and 1200°C. The structural characteristics such as porosity, grain size, fracture surface and hardness were analyzed by scan electron microscopy and X-ray diffraction, Archimedes densitometry, micro-hardness tester. The corresponding results indicated an increase in the densification and hardness property of the alloy as the temperature increases. The residual porosity of the alloy reduces with respect to the sintering temperature and in contrast, the grain size was enhanced. The study of the mechanical properties, including hardness, densification shows that optimum properties were obtained for the sintering temperature of 1100°C. The advantages of high sinterability of Ni-17Cr alloy using milled powders and microstructural details were discussed.

Keywords: densification, grain growth, milling, nanostructured materials, sintering temperature

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Authors: Sahar Fahmy Mehanna

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Wild fisheries and aquaculture offer excellent opportunities to decrease hunger and improve nutrition, relieve poverty, create economic growth and guarantee healthier use of natural resources. Employment in fisheries and aquaculture has grown continuously quicker than in the agriculture sector, providing up to 55 million jobs worldwide. Fisheries and aquaculture supplied Egypt with 2.1 million tons of fish in 2021, mostly used as food for people. Fish production in Egypt has grown dramatically in the last three decades, where fish production increased from about 346 thousand tons in 1990 to up to 2.1 million tons in 2021. In contrast to natural resources, which increased by only 30% in the period from 1990 to 2021, aquaculture production increased by 2502% during the same period. The majority of wild fisheries production in Egypt arises from coastal areas, where pollution is one of the main challenges severely affected both the productivity and quality of fish stocks. Our marine resources are at the risk of irreversible loss to habitats, ecological functions, and biodiversity because of overfishing, pollution, destructive fishing methods, climatic changes, unsustainable coastal area development and the competing demands from different industrial uses and human activities. Illegal, Unreported and Unregulated (IUU) Fishing continues to be a big challenge to achieve sustainable fisheries. Furthermore, poor governance, management and practices are a further challenge. Reducing overfishing, stimulating responsible and sustainable fisheries management, applying aquaculture new and friendly practices and conserving the marine environment health are among the government’s best opportunities to provide highly nutritious food to the increasing population in Egypt. The present presentation will discuss the fishery regulations in the Egyptian marine fisheries that taken to maintain, protect and promote the different Egyptian marine environments and to what extent these regulations were effective.

Keywords: egypt, marine fisheries, fishery regulations, fisheries management, Marine ecosystem conservation

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Authors: Anuja Singh, Avik K. Pati, Ashok K. Mishra

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Organic fluorophores with π-conjugated scaffolds are important because of their interesting optoelectronic properties. In recent years, our lab has been engaged in understanding the photophysics of small diacetylene bridged fluorophores and found the diynes as a promising class of π-conjugated fluorophores. Building on this understanding, recently we have focused on the photophysics of a less explored class of cross-conjugated Y-shaped enediynes (one double and two triple bonds). Here we present the photophysical properties of such enediynes which show interesting photophysical properties that include dual emissions from locally excited (LE) and intramolecular charge transfer (ICT) states and ring size dependent aggregate fluorescence in non-aqueous media. The dyes also show prominent aggregate fluorescence in mixed-aqueous solvents and solid powder form. We further show that the solid state fluorescence can be reversibly switched multiple of cycles by external stimuli, highlighting their potential applications in solid states. The enediynes with push-pull electronic substituents/moieties exhibit high contrast fluorescence color switching upon continuous photon illumination. The intriguing photophysical outcomes of the enediynyl fluorophores are judiciously exploited to generate single-component white light emission in binary solvent mixtures and sense polar aprotic vapor in polymer film matrices. The photophysical behavior of the dyes is further successfully utilized to monitor the microenvironment changes of biologically relevant anisotropic media such as bile salts. In summary, the newly introduced cross-conjugated enediynes enrich the toolbox of organic fluorophores and vouch to display versatile applications.

Keywords: aggregation in solution and solid state, enediynes, physical photochemistry and photophysics, vapor sensing and white light emission

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Authors: Zaida Perez-Bassart, Berta Polanco-Estibalez, Maria Jose Fabra, Amparo Lopez-Rubio, Antonio Martinez-Abad

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Mushroom production has enormously increased in recent years, not only as food products but also for applications in pharmaceuticals, nutraceuticals, and cosmetics. Consequently, interest in its chemical composition, nutritional value, and therapeutic properties has also increased. Fungi are rich in bioactive compounds such as polysaccharides, polyphenols, glycopeptides, and ergosterol, of great medicinal value, but within polysaccharides, β-glucans are the most prominent molecules. They are formed by D-glucose monomers, linked by β-glucosidic bonds β-(1,3) with side chains linked by β-(1,6) bonds. The number and position of the β-(1,6) branches strongly influence the arrangement of the tertiary structure, which, together with the molecular weight, determine the different attributed bioactivities (immunostimulating, anticancer, antimicrobial, prebiotic, etc.) and physico-chemical properties (solubility, bioaccessibility, viscosity or emulsifying). On the other hand, there is a growing interest in the study of fungi as an alternative source of chitin obtained from the by-products of the fungal industry. In this work, a cascade extraction process using aqueous neutral and alkaline treatments was carried out for Grifola frondosa and Lentinula edodes, and the compositional analysis and functional properties of each fraction were characterized. Interestingly, the first fraction obtained by using aqueous treatment at room temperature was the richest in polysaccharides, proteins, and polyphenols, thus obtaining a greater antioxidant capacity than in the other fractions. In contrast, the fractions obtained by alkaline treatments showed a higher degree of β-glucans purification compared to aqueous extractions but a lower extraction yield. Results revealed the different structural recalcitrance of β-glucans, preferentially linked to proteins or chitin depending on the fungus type, which had a direct impact on the functionalities and bioactivities of each fraction.

Keywords: fungi, mushroom, β-glucans, chitin

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Authors: Aidana Arynbek

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This paper attempts to offer an alternative to the explanation of the politics of great powers in Caspian politics. Since many researchers have analysed the politics of great powers in the region with the focus on materialism, this paper attempts to bring a sociological inquiry into analysing inter-state behaviour. The constructivist concept of Alexander Wendt will be applied to analyse Russia’s relation with The United States, China and Iran; the main argument is emphasis on the power of ideational forces over material ones. Moreover, the innovative contribution of Wendt regarding the understanding of anarchy to the study of International Relations (IR) will be applied; in his words, ‘anarchy is what states make of it’. A neo-realist perspective implies that with the structure of international politics, Russia treats all great powers as rivals through engagement in power politics; however, Wendt’s approach is able to explain the reason behind the state’s behaviour towards power politics, and this is about not only international structure, but also identity. The understanding of identity answers the question of how Russia came about to follow different actions in relation to Iran and China in contrast to The United States. This paper will be divided into five chapters. The first chapter will explain the constructivism of Alexander Wendt; the second chapter will give a brief background to The Caspian Sea Region (CSR); the third chapter will explain the formation of Russia’s identity towards The United States, and this will be applied to analyse Russia’s relation to The U.S in The CSR. Similarly with China, the fourth chapter will explain Russia’s identity and its relations in The CSR, and finally, the fifth chapter will show Russia’s identity towards Iran and its relation to Iran in The CSR. It will be concluded that the analysis of the politics between great powers in seeking to access one of the richest regions, The Caspian Basin, will show that international politics is not fixed, but constructed by human action and cognition. Reality in the politics of great powers in The Caspian Sea Region is socially constructed. This paper is not interested in how things are, but how they became what they are. That is to say, how Russia’s foreign policies towards great powers became what they are.

Keywords: Alexander Wendt, Caspian sea, identity, Russia, socially constructed

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Authors: Florian Vincent Haase, Adrian Dierl, Anna Henke, Ralf Woll, Ennes Sarradj

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Structured sheet metals and structured sandwich sheet metals are three-dimensional, lightweight structures with increased stiffness which are used in the automotive industry. The impedance, a figure of resistance of a structure to vibrations, will be determined regarding plain sheets, structured sheets, and structured sandwich sheets. The aim of this paper is generating an experimental design in order to minimize costs and duration of experiments. The design of experiments will be used to reduce the large number of single tests required for the determination of correlation between the impedance and its influencing factors. Full and fractional factorials are applied in order to systematize and plan the experiments. Their major advantages are high quality results given the relatively small number of trials and their ability to determine the most important influencing factors including their specific interactions. The developed full factorial experimental design for the study of plain sheets includes three factor levels. In contrast to the study of plain sheets, the respective impedance analysis used on structured sheets and structured sandwich sheets should be split into three phases. The first phase consists of preliminary tests which identify relevant factor levels. These factor levels are subsequently employed in main tests, which have the objective of identifying complex relationships between the parameters and the reference variable. Possible post-tests can follow up in case additional study of factor levels or other factors are necessary. By using full and fractional factorial experimental designs, the required number of tests is reduced by half. In the context of this paper, the benefits from the application of design for experiments are presented. Furthermore, a multistage approach is shown to take into account unrealizable factor combinations and minimize experiments.

Keywords: structured sheet metals, structured sandwich sheet metals, impedance measurement, design of experiment

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Authors: N. Lakshmipathy, Ch. S. N. Murthy, M. Aruna

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The design of lighting systems for surface mines is not an easy task because of the unique environment and work procedures encountered in the mines. The primary objective of this paper is to identify the major problems encountered in mine lighting application and to provide guidance in the solution of these problems. In the surface mining reflectance of surrounding surfaces is one of the important factors, which improve the vision, in the night hours. But due to typical working nature in the mines it is very difficult to fulfill these requirements, and also the orientation of the light at work site is a challenging task. Due to this reason machine operator and other workers in a mine need to be able to orient themselves in a difficult visual environment. The haul roads always keep on changing to tune with the mining activity. Other critical area such as dumpyards, stackyards etc. also change their phase with time, and it is difficult to illuminate such areas. Mining is a hazardous occupation, with workers exposed to adverse conditions; apart from the need for hard physical labor, there is exposure to stress and environmental pollutants like dust, noise, heat, vibration, poor illumination, radiation, etc. Visibility is restricted when operating load haul dumper and Heavy Earth Moving Machinery (HEMM) vehicles resulting in a number of serious accidents. one of the leading causes of these accidents is the inability of the equipment operator to see clearly people, objects or hazards around the machine. Results indicate blind spots are caused primarily by posts, the back of the operator's cab, and by lights and light brackets. The careful designed and implemented, lighting systems provide mine workers improved visibility and contribute to improved safety, productivity and morale. Properly designed lighting systems can improve visibility and safety during working in the opencast mines.

Keywords: contrast, efficacy, illuminance, illumination, light, luminaire, luminance, reflectance, visibility

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Authors: Panagodage Janaka Sampath Fernando

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Brain circulation has become a buzzword in the skilled migration literature. However, promoting brain circulation; returning of skilled migrants is challenging. Success stories in Asia, for instances, Taiwan, and China, are results of rigorous policy interventions of the respective governments. Nonetheless, the same policy mix has failed in other countries making it skeptical to attribute the success of brain circulation to the policy interventions per se. The paper seeks to answer whether the success of brain circulation within the Knowledge Services Industry (KSI) in Sri Lanka is a policy driven or a market driven process. Mixed method approach, which is a combination of case study and survey methods, was employed. Qualitative data derived from ten case studies of returned entrepreneurs whereas quantitative data generated from a self-administered survey of 205 returned skilled migrants (returned skilled employees and entrepreneurs) within KSI. The pull factors have driven the current flow of brain circulation within KSI but to a lesser extent, push factors also have influenced. The founding stone of the industry has been laid by a group of returned entrepreneurs, and the subsequent growth of the industry has attracted returning skilled employees. Sri Lankan government has not actively implemented the reverse brain drain model, however, has played a passive role by creating a peaceful and healthy environment for the industry. Therefore, in contrast to the other stories, brain circulation within KSI has emerged as a market driven process with minimal government interventions. Entrepreneurs play the main role in a market-driven process of brain circulation, and it is free from the inherent limitations of the reverse brain drain model such as discriminating non-migrants and generating a sudden flow of low-skilled migrants. Thus, to experience a successful brain circulation, developing countries should promote returned entrepreneurs by creating opportunities in knowledge-based industries.

Keywords: brain circulation, knowledge services industry, return migration, Sri Lanka

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Authors: Madiha El Awamie, Catherine Rees

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Natural preservatives have been used as alternatives to traditional chemical preservatives; however, a limited number have been commercially developed and many remain to be investigated as sources of safer and effective antimicrobials. In this study, we have been investigating the antimicrobial activity of an extract of Glycyrrhiza glabra (liquorice) that was provided as a waste material from the production of liquorice flavourings for the food industry, and to investigate if this retained the expected antimicrobial activity so it could be used as a natural preservative. Antibacterial activity of liquorice extract was screened for evidence of growth inhibition against eight species of Gram-negative and Gram-positive bacteria, including Listeria monocytogenes, Listeria innocua, Staphylococcus aureus, Enterococcus faecalis and Bacillus subtilis. The Gram-negative bacteria tested include Pseudomonas aeruginosa, Escherichia coli and Salmonella typhimurium but none of these were affected by the extract. In contrast, for all of the Gram-positive bacteria tested, growth was inhibited as monitored using optical density. However parallel studies using viable count indicated that the cells were not killed meaning that the extract was bacteriostatic rather than bacteriocidal. The Minimum Inhibitory Concentration [MIC] and Minimum Bactericidal Concentration [MBC] of the extract was also determined and a concentration of 50 µg ml^-1 was found to have a strong bacteriostatic effect on Gram-positive bacteria. Microscopic analysis indicated that there were changes in cell shape suggesting the cell wall was affected. In addition, the use of a reporter strain of Listeria transformed with the bioluminescence genes luxABCDE indicated that cell energy levels were reduced when treated with either 12.5 or 50 µg ml^-1 of the extract, with the reduction in light output being proportional to the concentration of the extract used. Together these results suggest that the extract is inhibiting the growth of Gram-positive bacteria only by damaging the cell wall and/or membrane.

Keywords: antibacterial activity, bioluminescence, Glycyrrhiza glabra, natural preservative

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Authors: Takahiro Saida, Takahiro Kogiso, Takahiro Maruyama

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The ordered structural carbon (OSC) material is expected to apply to the electrode of secondary batteries, the catalyst supports, and the biomaterials because it shows the low substance-diffusion resistance by its uniform pore size. In general, the OSC material is synthesized using the template material. Changing size and shape of this template provides the pore size of OSC material according to the purpose. Depositing the oxide nanosheets on the polymer sphere template by the layer by layer (LbL) method was reported as one of the preparation methods of OSC material. The LbL method can provide the controlling thickness of structural wall without the surface modification. When the preparation of the uniform carbon sphere prepared by the LbL method which composed of the graphene oxide wall and the polymethyl-methacrylate (PMMA) core, the reduction treatment will be the important object. Since the graphene oxide has poor electron conductivity due to forming a lot of functional groups on the surface, it could be hard to apply to the electrode of secondary batteries and the catalyst support of fuel cells. In this study, the graphene oxide wall of carbon sphere was reduced by the thermal treatment under the vacuum conditions, and its crystalline structure and electronic state were characterized. Scanning electron microscope images of the carbon sphere after the heat treatment at 300ºC showed maintaining sphere shape, but its shape was collapsed with increasing the heating temperature. In this time, the dissolution rate of PMMA core and the reduction rate of graphene oxide were proportionate to heating temperature. In contrast, extending the heating time was conducive to the conservation of the sphere shape. From results of X-ray photoelectron spectroscopy analysis, its electronic state of the surface was indicated mainly sp² carbon. From the above results, we succeeded in the synthesis of the sphere structure composed by the reduction graphene oxide.

Keywords: carbon sphere, graphene oxide, reduction, layer by layer

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