Search results for: transmission adequacy

Authors: Afshin Moazami, Andrea Schiffauerova

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The objective of this work is to investigate the development and the role of collaboration networks in the creation of knowledge and innovations in the US and Canada, with a special focus on Quebec. In order to create scientific networks, the data on journal articles were extracted from SCOPUS, and the networks were built based on the co-authorship of the journal papers. For innovation networks, the USPTO database was used, and the networks were built on the patent co-inventorship. Various indicators characterizing the evolution of the network structure and the positions of the researchers and inventors in the networks were calculated. The comparison between the United States, Canada, and Quebec was then carried out. The preliminary results show that the nature of scientific collaboration networks differs from the one seen in innovation networks. Scientists work in bigger teams and are mostly interconnected within one giant network component, whereas the innovation network is much more clustered and fragmented, the inventors work more repetitively with the same partners, often in smaller isolated groups. In both Canada and the US, an increasing tendency towards collaboration was observed, and it was found that networks are getting bigger and more centralized with time. Moreover, a declining share of knowledge transfers per scientist was detected, suggesting an increasing specialization of science. The US collaboration networks tend to be more centralized than the Canadian ones. Quebec shares a lot of features with the Canadian network, but some differences were observed, for example, Quebec inventors rely more on the knowledge transmission through intermediaries.

Keywords: Canada, collaboration, innovation network, scientific network, Quebec, United States

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Authors: Z. Ž. Lazarević, D. L. Sekulić, V. N. Ivanovski, N. Ž. Romčević

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NiFe2O4 (nickel ferrite), ZnFe2O4 (zinc ferrite) and Ni0.5Zn0.5Fe2O4 (nickel-zinc ferrite) were prepared by mechanochemical route in a planetary ball mill starting from mixture of the appropriate quantities of the Ni(OH)2/Fe(OH)3, Zn(OH)2/Fe(OH)3 and Ni(OH)2/Zn(OH)2/Fe(OH)3 hydroxide powders. In order to monitor the progress of chemical reaction and confirm phase formation, powder samples obtained after 25 h, 18 h and 10 h of milling were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), IR, Raman and Mössbauer spectroscopy. It is shown that the soft mechanochemical method, i.e. mechanochemical activation of hydroxides, produces high quality single phase ferrite samples in much more efficient way. From the IR spectroscopy of single phase samples it is obvious that energy of modes depends on the ratio of cations. It is obvious that all samples have more than 5 Raman active modes predicted by group theory in the normal spinel structure. Deconvolution of measured spectra allows one to conclude that all complex bands in the spectra are made of individual peaks with the intensities that vary from spectrum to spectrum. The deconvolution of Raman spectra allows to separate contributions of different cations to a particular type of vibration and to estimate the degree of inversion.

Keywords: ferrites, Raman spectroscopy, IR spectroscopy, Mössbauer measurements

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Authors: Woei-Shyan Lee, Yu-Liang Chuang

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The nano-mechanical properties of as-deposited Cu/Si thin films indented to a depth of 2000 nm are investigated using a nanoindentation technique. The nanoindented specimens are annealed at a temperature of either 160 °C or 210°C, respectively. The microstructures of the as-deposited and annealed samples are then examined via transmission electron microscopy (TEM). The results show that both the loading and the unloading regions of the load-displacement curve are smooth and continuous, which suggests that no debonding or cracking occurs during nanoindentation. In addition, the hardness and Young’s modulus of the Cu/Si thin films are found to vary with the nanoindentation depth, and have maximum values of 2.8 GPa and 143 GPa, respectively, at the maximum indentation depth of 2000 nm. The TEM observations show that the region of the Cu/Si film beneath the indenter undergoes a phase transformation during the indentation process. In the case of the as-deposited specimens, the indentation pressure induces a completely amorphous phase within the indentation zone. For the specimens annealed at a temperature of 160°C, the amorphous nature of the microstructure within the indented zone is maintained. However, for the specimens annealed at a higher temperature of 210°C, the indentation affected zone consists of a mixture of amorphous phase and nanocrystalline phase. Copper silicide (η-Cu3Si) precipitates are observed in all of the annealed specimens. The density of the η-Cu3Si precipitates is found to increase with an increasing annealing temperature.

Keywords: nanoindentation, Cu/Si thin films, microstructural evolution, annealing temperature

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Authors: Adeline Stals

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The transformation of architectural design practices has been underway for almost forty years due to the development and democratization of computer technology. New and more efficient tools are constantly being proposed to architects, amplifying a technological wave that sometimes stimulates them, sometimes overwhelms them, depending essentially on their digital culture and the context (socio-economic, structural, organizational) in which they work on a daily basis. Our focus is on VR, AR, and MR technologies dedicated to architecture. The commercialization of affordable headsets like the Oculus Rift, the HTC Vive or more low-tech like the Google CardBoard, makes it more accessible to benefit from these technologies. In that regard, researchers report the growing interest of these tools for architects, given the new perspectives they open up in terms of workflow, representation, collaboration, and client’s involvement. However, studies rarely mention the consequences of the sample studied on results. Our research provides an overview of VR, AR, and MR researches among a corpus of papers selected from conferences and journals. A closer look at the sample of these research projects highlights the necessity to take into consideration the context of studies in order to develop tools truly dedicated to the real practices of specific architect profiles. This literature review formalizes milestones for future challenges to address. The methodology applied is based on a systematic review of two sources of publications. The first one is the Cumincad database, which regroups publications from conferences exclusively about digital in architecture. Additionally, the second part of the corpus is based on journal publications. Journals have been selected considering their ranking on Scimago. Among the journals in the predefined category ‘architecture’ and in Quartile 1 for 2018 (last update when consulted), we have retained the ones related to the architectural design process: Design Studies, CoDesign, Architectural Science Review, Frontiers of Architectural Research and Archnet-IJAR. Beside those journals, IJAC, not classified in the ‘architecture’ category, is selected by the author for its adequacy with architecture and computing. For all requests, the search terms were ‘virtual reality’, ‘augmented reality’, and ‘mixed reality’ in title and/or keywords for papers published between 2015 and 2019 (included). This frame time is defined considering the fast evolution of these technologies in the past few years. Accordingly, the systematic review covers 202 publications. The literature review on studies about XR technologies establishes the state of the art of the current situation. It highlights that studies are mostly based on experimental contexts with controlled conditions (pedagogical, e.g.) or on practices established in large architectural offices of international renown. However, few studies focus on the strategies and practices developed by offices of smaller size, which represent the largest part of the market. Indeed, a European survey studying the architectural profession in Europe in 2018 reveals that 99% of offices are composed of less than ten people, and 71% of only one person. The study also showed that the number of medium-sized offices is continuously decreasing in favour of smaller structures. In doing so, a frontier seems to remain between the worlds of research and practice, especially for the majority of small architectural practices having a modest use of technology. This paper constitutes a reference for the next step of the research and for further worldwide researches by facilitating their contextualization.

Keywords: architectural design, literature review, SME, XR technologies

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Authors: N. Reza Pour, S. Chuah, T. Vo

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Background: Vertebral artery dissection (VAD) is a rare complication of pregnancy. It can occur spontaneously or following a traumatic event. The pathogenesis is unclear. Predisposing factors include chronic hypertension, Marfan’s syndrome, fibromuscular dysplasia, vasculitis and cystic medial necrosis. Physiological changes of pregnancy have also been proposed as potential mechanisms of injury to the vessel wall. The clinical presentation varies and it can present as a headache, neck pain, diplopia, transient ischaemic attack, or an ischemic stroke. Isolated cases of VAD in pregnancy and puerperium have been reported in the literature. One case was found to have posterior circulation stroke as a result of bilateral VAD and labour was induced at 37 weeks gestation for preeclampsia. Another patient at 38 weeks with severe neck pain that persisted after induction for elevated blood pressure and arteriography showed right VAD postpartum. A single case of lethal VAD in pregnancy with subsequent massive subarachnoid haemorrhage has been reported which was confirmed by the autopsy. Case Presentation: We report two cases of vertebral artery dissection in pregnancy. The first patient was a 32-year-old primigravida presented at the 38th week of pregnancy with the onset of early labour and blood pressure (BP) of 130/70 on arrival. After 2 hours, the patient developed a severe headache with blurry vision and BP was 238/120. Despite treatment with an intravenous antihypertensive, she had eclamptic fit. Magnesium solfate was started and Emergency Caesarean Section was performed under the general anaesthesia. On the second day after the operation, she developed left-sided neck pain. Magnetic Resonance Imaging (MRI) angiography confirmed a short segment left vertebral artery dissection at the level of C3. The patient was treated with aspirin and remained stable without any neurological deficit. The second patient was a 33-year-old primigavida who was admitted to the hospital at 36 weeks gestation with BP of 155/105, constant headache and visual disturbances. She was medicated with an oral antihypertensive agent. On day 4, she complained of right-sided neck pain. MRI angiogram revealed a short segment dissection of the right vertebral artery at the C2-3 level. Pregnancy was terminated on the same day with emergency Caesarean Section and anticoagulation was started subsequently. Post-operative recovery was complicated by rectus sheath haematoma requiring evacuation. She was discharged home on Aspirin without any neurological sequelae. Conclusion: Because of collateral circulation, unilateral vertebral artery dissections may go unrecognized and may be more common than suspected. The outcome for most patients is benign, reflecting the adequacy of the collateral circulation in young patients. Spontaneous VAD is usually treated with anticoagulation or antiplatelet therapy for a minimum of 3-6 months to prevent future ischaemic events, allowing the dissection to heal on its own. We had two cases of VAD in the context of hypertensive disorders of pregnancy with an acceptable outcome. A high level of vigilance is required particularly with preeclamptic patients presenting with head/neck pain to allow an early diagnosis. This is as we hypothesize, early and aggressive management of vertebral artery dissection may potentially prevent further complications.

Keywords: eclampsia, preeclampsia, pregnancy, Vertebral Artery Dissection

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Authors: Anusit Punsirichaiyakul, Tosaphol Ratniyomchai, Thanatchai Kulworawanichpong

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The paper aims to study the energy storage system in the form of gravity energy by the weight of concrete stacks. This technology has the potential to replace expensive battery storage. This paper is a trial plan in abandoned mines in Thailand. This is to start with construct concrete boxes to be stacked vertically or obliquely to form appropriate shapes and, therefore, to store the potential energy. The stored energy can be released or discharged back to the system by deploying the concrete stacks to the ground. This is to convert the potential energy stored in the concrete stacks to the kinetic energy of the concrete box movement. This design is incorporating mechanical transmission to reduce the height of the concrete stacks. This study also makes a comparison between the energy used to construct concrete stacks in various shapes and the energy to deploy all the concrete boxes to ground. This paper consists of 2 test systems. The first test is to stack the concrete in vertical shape. The concrete stack has a maximum height of 50 m with a gear ratio of 1:200. The concrete box weight is 115 tons/piece with a total stored energy of 1800 kWh. The oblique system has a height of 50 m with a similar gear ratio of 1:200. The weight of the concrete box is 90 tons/piece and has a total stored energy of 1440 kWh. Also, it has an overall efficiency of 65% and a lifetime of 50 years. This storage has higher storage densities compared to other systems.

Keywords: gravity, concrete stacks, vertical, oblique

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Authors: Syue-Liang Lin, C. Allen Chang

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Luminescence imaging is an important technique used in biomedical research and clinical diagnostic applications in recent years. Concurrently, the development of NIR luminescence probes / imaging contrast agents has helped the understanding of the structural and functional properties of cells and animals. Photodynamic therapy (PDT) is used clinically to treat a wide range of medical conditions, but the therapeutic efficacy of general PDT for deeper tumor was limited by the penetration of excitation source. The tumor targeting biomedical nanomaterials UCNP@PS (upconversion nanoparticle conjugated with photosensitizer) for photodynamic therapy and near-infrared imaging of cancer will be developed in our study. Synthesis and characterization of biomedical nanomaterials were completed in this studies. The spectrum of UCNP was characterized by photoluminescence spectroscopy and the morphology was characterized by Transmission Electron Microscope (TEM). TEM and XRD analyses indicated that these nanoparticles are about 20~50 nm with hexagonal phase. NaYF₄:Ln³⁺ (Ln= Yb, Nd, Er) upconversion nanoparticles (UCNPs) with core / shell structure, synthesized by thermal decomposition method in 300°C, have the ability to emit visible light (upconversion: 540 nm, 660 nm) and near-infrared with longer wavelength (downconversion: NIR: 980 nm, 1525 nm) by absorbing 800 nm NIR laser. The information obtained from these studies would be very useful for applications of these nanomaterials for bio-luminescence imaging and photodynamic therapy of deep tumor tissue in the future.

Keywords: Near Infrared (NIR), lanthanide, core-shell structure, upconversion, theranostics

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Authors: Xiang-Yao Zheng, Jen-Cheng Wang, Joe-Air Jiang

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Improving the line ampacity while using existing power grids is an important issue that electricity dispatchers are now facing. Using the information provided by the dynamic thermal rating (DTR) of transmission lines, an overhead power grid can operate safely. However, dispatchers usually lack real-time DTR information. Thus, this study proposes a long-short-term memory (LSTM)-based method, which is one of the neural network models. The LSTM-based method predicts the DTR of lines using the weather data provided by Central Weather Bureau (CWB) of Taiwan. The possible thermal bottlenecks at different locations along the line and the margin of line ampacity can be real-time determined by the proposed LSTM-based prediction method. A case study that targets the 345 kV power grid of TaiPower in Taiwan is utilized to examine the performance of the proposed method. The simulation results show that the proposed method is useful to provide the information for the smart grid application in the future.

Keywords: electricity dispatch, line ampacity prediction, dynamic thermal rating, long-short-term memory neural network, smart grid

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Authors: Adeleye O. O., T. M. Obuotor, A. O. Kolawole, I. O. Opowoye, M. I. Olasoju, L. T. Egbeyale, R. A. Ajadi

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This study investigated the effect of Lagenaria breviflora on broiler poultry birds, including its effect on the microbial count of the poultry droppings. A total of 240-day-old broiler chicks were randomly assigned to six groups, with four replicates per group. The first group was the control, while the other four groups were fed water containing 300g/L and 500g/L concentrations of Lagenaria breviflora twice and thrice daily. The microbial load was determined using the plate count method. The results showed that the administration of Lagenaria breviflora in the water of broiler birds significantly improved their growth performance with an average weight gain range of 1.845g - 2.241g. Mortality rate was at 0%. The study also found that Lagenaria breviflora had a significant effect on the microbial count of the poultry droppings with colony count values from 3.5 x 10-7 - 9.9 x10-7CFU/ml, The total coliforms (Escherichia coli, and Salmonella sp.) was obtained as 1 x 10 -5CFU/ml. The reduction in microbial counts of the poultry droppings could be attributed to the antimicrobial properties of Lagenaria breviflora, which contain phytochemicals reported to possess antimicrobial activity. Therefore, the inclusion of Lagenaria breviflora in the diets of broiler poultry could be an effective strategy for improving growth performance and immune function and reducing the microbial load of poultry droppings, which can help to mitigate the risk of disease transmission to humans and other animals.

Keywords: gut microbes, bacterial count, lagenaria breviflora, coliforms

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Authors: Adeyemi Isaac Sanusi, Gueguim E. B. Kana

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Nanoparticles have received attention of the scientific community due to their biotechnological potentials. They exhibit advantageous size, shape and concentration-dependent catalytic, stabilizing, immunoassays and immobilization properties. This study investigates the impact of metallic oxide nanoparticles (NPs) on ethanol production by Saccharomyces cerevisiae BY4743. Nine different nanoparticles were synthesized using precipitation method and microwave treatment. The nanoparticles synthesized were characterized by Fourier Transform Infra-Red spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Fermentation processes were carried out at varied NPs concentrations (0 – 0.08 wt%). Highest ethanol concentrations were achieved after 24 h using Cobalt NPs (5.07 g/l), Copper NPs (4.86 g/l) and Manganese NPs (4.74 g/l) at 0.01 wt% NPs concentrations, which represent 13%, 8.7% and 5.4% increase respectively over the control (4.47 g/l). The lowest ethanol concentration (0.17 g/l) was obtained when 0.08 wt% of Silver NPs was used. And lower ethanol concentrations were observed at higher NPs concentration. Ethanol concentration decrease after 24 h for all the processes. In all set up with NPs, the pH was observed to be stable and the stability was directly proportional to nanoparticles concentrations. These findings suggest that the presence of some of the NPs in the bioprocesses has catalytic and pH stabilizing potential. Ethanol production by Saccharomyces cerevisiae BY4743 was enhanced in the presence of Cobalt NPs, Copper NPs and Manganese NPs. Optimization study using response surface methodology (RSM) will further elucidate the impact of these nanoparticles on bioethanol production.

Keywords: agitation, bioethanol, nanoparticles concentration, optimization, pH value

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Authors: Marziye Hadian, Alireza Jabbari

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Background: The World Health Organization has identified COVID-19 as a public health emergency and is urging governments to stop the virus transmission by adopting appropriate policies. In this regard, the countries have taken different approaches to cutting the chain or controlling the spread of the disease. Methods: The present study was a systematize review of publications relating to prevention strategies for covid-19 disease. The study was carried out based on the PRISMA guidelines and CASP for articles and AACODS for grey literature. Finding: The study findings showed that in order to confront the COVID-19 epidemic, in general, there are three approaches of "mitigation", "active control" and "suppression" and four strategies of "quarantine", "isolation", "social distance" as well as "lockdown" in both individual and social dimensions to deal with epidemics that the choice of each approach requires specific strategies and has different effects when it comes to controlling and inhibiting the disease. Conclusion: The only way to control the disease is to change your behavior and lifestyle. In addition to prevention strategies, use of masks, observance of personal hygiene principles such as regular hand washing and non-contact of contaminated hands with the face, as well as observance of public health principles such as control of sneezing and coughing, safe extermination of personal protective equipment, etc. have not been included in the category of prevention tools. However, it has a great impact on controlling the epidemic, especially the new coronavirus epidemic.

Keywords: novel corona virus, COVID-19, prevention tools, prevention strategies

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Authors: Karl Eddie T. Malabanan

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Due to the quick transmission and public health risk of coronavirus disease, schools and universities have shifted to distant learning. Teachers everywhere were forced to shift gears instantly in order to react to the needs of students and families using synchronous and asynchronous virtual teaching. This study aims to explore the lived experiences of physical education teachers who are currently experiencing remote learning in teaching during the time of the COVID-19 pandemic. Specifically, the challenges that the physical education teachers encounter during remote learning and teaching. The participants include 12 physical education teachers who have taught in higher education institutions for at least five years. The researcher utilized qualitative research; specifically, the researcher used Consensual Qualitative Research (CQR). The results of this study showed that there are five categories for the Lived Experiences of Physical Education Teachers with thirty-one subcategories. This study revealed that physical education teachers experienced very challenging situations during the time of the pandemic. It also found that students had challenges in the abrupt transition from traditional to virtual learning classes, but it also showed that students are tenacious and willing to face any adversity. The researcher also finds that teachers are mentally drained during this time. Furthermore, one of the main focuses for the teachers should be on improving their well-being. And lastly, to cope with the challenges, teachers employ socializing to relieve tension and anxiety.

Keywords: lived experiences, consensual qualitative research, pandemic, education

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Authors: Margita Čanigová, Jana Račková, Miroslav Kročko, Viera Ducková, Vladimíra Kňazovická

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The aim of the study was to test the milk samples in terms of enterococci presence and their counts. Tested samples were as follows: raw cow milk, raw cow milk stored at 10°C for 16 hours and milk pasteurised at 72°C for 15 seconds. The typical colonies were isolated randomly and identified by classical biochemical test - EN-COCCUS test (Lachema, CR) and by PCR. Isolated strains were tested in terms of antibiotic resistance by well diffusion method. Examined antibiotics were: vancomycin (30 μg/disc), gentamicin (120 μg/disc), erythromycin (15 μg/disc), teicoplanine (30 μg/disc), ampicillin (10 μg/disc) and tetracycline (30 μg/disc). Average value of enterococci counts in raw milk cistern samples (n=30) was 8.25 ± 1.37 ×103 CFU/cm3. Storage tank milk samples (n=30) showed an increase (P > 0.05) and average value was 9.16 ± 1.49 × 103 CFU/cm3. Occurrence of enterococci in pasteurized milk (n=30) was sporadic and their counts were mostly below 10 CFU/cm3. Overall, 96 enterococci strains were isolated. In samples of raw cow milk and stored raw cow milk, Enterococcus faecalis was a dominant species (58.1% and 71.7%, respectively), followed by E. faecium (16.3% and 0%, respectively). Enterococcus mundtii, E. casseliflavus, E. durans and E. gallinarum were isolated, too. Resistances to ampicillin, erythromycin, gentamicin, tetracycline and vancomycin were found in 7.29%, 3.13%, 4.00%, 13.54% and 10.42% of isolated enterococci strains, respectively. Resistance to teicoplanine was not found in any isolated strain. All Vancomycin-Resistant Enterococci (VRE) belonged to E. faecalis. Obtained results confirmed that raw milk is a potential risk of enterococci resistant to antibiotics transmission into the food chain.

Keywords: antibiotic resistance, enterococci, milk, biosystems engineering

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Authors: Jacob Wahl, Jane Zhang

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This paper describes the development and characterization of a prototype IoT network for use with agricultural imaging and monitoring applications. The sensor and gateway nodes are designed using the ESP32 SoC with integrated Bluetooth Low Energy 4.2 and Wi-Fi. A development board, the Arducam IoTai ESP32, is used for prototyping, testing, and power measurements. Google’s Firebase is used as the cloud storage site for image data collected by the sensor. The sensor node captures images using the OV2640 2MP camera module and transmits the image data to the gateway via Bluetooth Low Energy. The gateway then uploads the collected images to Firebase via a known nearby Wi-Fi network connection. This image data can then be processed and analyzed by computer vision and machine learning pipelines to assess crop growth or other needs. The sensor node achieves a wireless transmission data throughput of 220kbps while consuming 150mA of current; the sensor sleeps at 162µA. The sensor node device lifetime is estimated to be 682 days on a 6600mAh LiPo battery while acquiring five images per day based on the development board power measurements. This network can be utilized by any application that requires high data rates, low power consumption, short-range communication, and large amounts of data to be transmitted at low-frequency intervals.

Keywords: Bluetooth low energy, ESP32, firebase cloud, IoT, smart farming

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Authors: Emie A. Salamangkit-Mirasol, Rinlee Butch M. Cervera

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Rice hull or rice husk (RH) is an agricultural waste obtained from milling rice grains. Since RH has no commercial value and is difficult to use in agriculture, its volume is often reduced through open field burning which is an environmental hazard. In this study, amorphous nanosilica from Philippine waste RH was prepared via acid precipitation method. The synthesized samples were fully characterized for its microstructural properties. X-ray diffraction pattern reveals that the structure of the prepared sample is amorphous in nature while Fourier transform infrared spectrum showed the different vibration bands of the synthesized sample. Scanning electron microscopy (SEM) and particle size analysis (PSA) confirmed the presence of agglomerated silica particles. On the other hand, transmission electron microscopy (TEM) revealed an amorphous sample with grain sizes of about 5 to 20 nanometer range and has about 95 % purity according to EDS analyses. The elemental mapping also suggests that leaching of rice hull ash effectively removed the metallic impurity such as potassium element in the material. Hence, amorphous nanosilica was successfully prepared via a low-cost acid precipitation method from Philippine waste rice hull. In addition, initial electrode performance of the synthesized samples as an anode material in Lithium Battery have been investigated.

Keywords: agricultural waste, anode material, nanosilica, rice hull

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Authors: Ofosuhene O. Apenteng, Noor Azina Ismail

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Over the last several years, concern has developed over how to minimize the spread of HIV/AIDS epidemic in many countries. AIDS epidemic has tremendously stimulated the development of mathematical models of infectious diseases. The transmission dynamics of HIV infection that eventually developed AIDS has taken a pivotal role of much on building mathematical models. From the initial HIV and AIDS models introduced in the 80s, various improvements have been taken into account as how to model HIV/AIDS frameworks. In this paper, we present the impact of migration on the spread of HIV/AIDS. Epidemic model is considered by a system of nonlinear differential equations to supplement the statistical method approach. The model is calibrated using HIV incidence data from Malaysia between 1986 and 2011. Bayesian inference based on Markov Chain Monte Carlo is used to validate the model by fitting it to the data and to estimate the unknown parameters for the model. The results suggest that the migrants stay for a long time contributes to the spread of HIV. The model also indicates that susceptible individual becomes infected and moved to HIV compartment at a rate that is more significant than the removal rate from HIV compartment to AIDS compartment. The disease-free steady state is unstable since the basic reproduction number is 1.627309. This is a big concern and not a good indicator from the public heath point of view since the aim is to stabilize the epidemic at the disease equilibrium.

Keywords: epidemic model, HIV, MCMC, parameter estimation

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Authors: Alparslan A. Balta, Hilmi Yurdakul, Orkun Tunckan, Servet Turan, Arife Yurdakul

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Si2N2O (Sinoite) is an inorganic-based oxynitride material that reveals promising phosphor candidates for white light-emitting diodes (WLEDs). However, there is now limited knowledge to explain the synthesis of Si2N2O for this purpose. Here, to the best of authors’ knowledge, we report the first time the production of Si2N2O based phosphors by CeO2, SiO2, Si3N4 from main starting powders, and Li2O sintering additive through spark plasma sintering (SPS) route. The processing parameters, e.g., pressure, temperature, and sintering time, were optimized to reach the monophase Si2N2O containing samples. The lattice parameter, crystallite size, and amount of formation phases were characterized in detail by X-ray diffraction (XRD). Grain morphology, particle size, and distribution were analyzed by scanning and transmission electron microscopes (SEM and TEM). Cathodoluminescence (CL) in SEM and photoluminescence (PL) analyses were conducted on the samples to determine the excitation, and emission characteristics of Ce3+ activated Si2N2O. Results showed that the Si2N2O phase in a maximum 90% ratio was obtained by sintering for 15 minutes at 1650oC under 30 MPa pressure. Based on the SEM-CL and PL measurements, Ce3+: Si2N2O phosphor shows a broad emission summit between 400-700 nm that corresponds to white light. The present research was supported by TUBITAK under project number 217M667.

Keywords: cerium, oxynitride, phosphors, sinoite, Si₂N₂O

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Authors: Stanely Nsubuga

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Background In Uganda, injection drug use is a growing but less studied problem. Preventing the transition to injection drug use may help prevent blood-borne viral transmission, but little is known about when and how people transition to injection drug use. A greater understanding of this transition process may aid in the country’s efforts to prevent the continued growth of injection drug use, HIV, and hepatitis C Virus (HCV) infection among people who inject drugs (PWID). Methods Using a rapid situation assessment framework, we conducted semi-structured interviews among 125 PWID (102 males and 23 females)—recruited through outreach and snow-ball sampling. Participants were interviewed about their experiences on when and how they transitioned into injection drug use and these issues were also discussed in 12 focus groups held with the participants. Results All the study participants started their drug use career with non-injecting forms including chewing, smoking, and sniffing before transitioning to injecting. Transitioning was generally described as a peer-driven and socially learnt behavior. The participants’ social networks and accessibility to injectable drugs on the market and among close friends influenced the time lag between first regular drug use and first injecting—which took an average of 4.5 years. By the age of 24, at least 81.6% (95.7% for females and 78.4% for males) had transitioned into injecting. Over 84.8% shared injecting equipment during their first injection, 47.2% started injecting because a close friend was already injecting, 26.4% desired to achieve a greater “high” (26.4%) which could reflect drug-tolerance, and 12% out of curiosity.

Keywords: People who Use Drugs, transition, injection drug use, Uganda

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Authors: Wilayat Ali, Li Sheng, Waleed Ahmed

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The ability of the robot to make simultaneously map of the environment and localize itself with respect to that environment is the most important element of mobile robots. To solve SLAM many algorithms could be utilized to build up the SLAM process and SLAM is a developing area in Robotics research. Robot Operating System (ROS) is one of the frameworks which provide multiple algorithm nodes to work with and provide a transmission layer to robots. Manyof these algorithms extensively in use are Hector SLAM, Gmapping and Cartographer SLAM. This paper describes a ROS-based Simultaneous localization and mapping (SLAM) library Google Cartographer mapping, which is open-source algorithm. The algorithm was applied to create a map using laser and pose data from 2d Lidar that was placed on a mobile robot. The model robot uses the gazebo package and simulated in Rviz. Our research work's primary goal is to obtain mapping through Cartographer SLAM algorithm in a static indoor environment. From our research, it is shown that for indoor environments cartographer is an applicable algorithm to generate 2d maps with LIDAR placed on mobile robot because it uses both odometry and poses estimation. The algorithm has been evaluated and maps are constructed against the SLAM algorithms presented by Turtlebot2 in the static indoor environment.

Keywords: SLAM, ROS, navigation, localization and mapping, gazebo, Rviz, Turtlebot2, slam algorithms, 2d indoor environment, cartographer

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Authors: Septiawan A. Saputro, Purnami Widyaningsih, Sutanto Sastraredja

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Measles is a disease which can spread caused by a virus and has been a priority’s Ministry of Health in Indonesia to be solved. Each infected person can be recovered and get immunity so that the spread of the disease can be constructed with susceptible infected recovered (SIR). To prevent the spread of measles transmission, the Ministry of Health holds vaccinations program. The aims of the research are to derive susceptible vaccinated infected recovered (SVIR) model, to determine the patterns of disease spread with SVIR model, and also to apply the SVIR model on the spread of measles in Indonesia. Based on the article, it can be concluded that the spread model of measles with vaccinations, that is SVIR model. It is a first-order differential equation system. The patterns of disease spread is determined by solution of the model. Based on that model Indonesia will be a measles-free nation in 2186 with the average of vaccinations scope about 88% and the average score of vaccinations failure about 4.9%. If it is simulated as Ministry of Health new programs with the average of vaccinations scope about 95% and the average score of vaccinations failure about 3%, then Indonesia will be a measles-free nation in 2184. Even with the average of vaccinations scope about 100% and no failure of vaccinations, Indonesia will be a measles-free nation in 2183. Indonesia’s target as a measles-free nation in 2020 has not been reached.

Keywords: measles, vaccination, susceptible infected recovered (SIR), susceptible vaccinated infected recovered (SVIR)

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Authors: Rongzhou Wang

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Research on designing nano-antibacterial agent with potent and long-lasting antibacterial property is demanding and provoking work. In this study, a core-shell AgBr/cationic polymer nanocomposite (AgBr/NPVP-H10) were synthesized and its structure confirmed by Fourier Transform Infrared Spectrometer (FT-IR), Nuclear Magnetic Resonance (1H NMR) and X-ray diffraction (XRD), and the cationic polymer contents were determined with Thermal Gravimetric Analyzer (TGA). The morphology was directly observed by Transmission Electron Microscope (TEM) which showed that the nanoparticle contains single core and organic shell and had an average diameter of 30.1 nm. The antibacterial test against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli illuminated that this nanocomposite had potent bactericidal activity, which can be attributed to the contact-killing of cationic polymers and releasing-killing of Ag+ ions. In addition, cationic polymer encapsulating AgBr cores gave the resin discs sustained release of Ag+ ions, which may result in long-lasting bactericidal activity. The AgBr/NPVP-H10 nanoparticle with the dual bactericidal capability and long term antimicrobial effect is a promising material aimed at preventing bacterial infection.

Keywords: core-shell nanocomposite, cationic polymer, dual antibacterial capability, long-lasting antibacterial activity

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Authors: Maryam Vaezjalali, Foad Davoodbeglou, Mehrnaz Mesdaghi, Hossein Goudarzi, Fariba Shojaei, Hourieh Aram

Abstract:

Introduction: Hepatitis B virus (HBV) infection causes chronic infection in human population, with high mortality. Some people are more susceptible to this infection. One of the high risk communities is mentally retarded children, who are institutionalized. Special conditions in these centers predispose children for HBV infection and transmission to healthy people. In this study our objective was to determine the prevalence of HBV infection among institutionalized mentally retarded children and study its associated risk factors. Materials and methods: In this study, 250 mentally retarded children (younger than 14 years old) were included. They were living in 5 nursing institutions, located in different parts of Tehran. HBsAg was measured in the sera of these patients by ELISA method. Results: Among 250 children, 20 children (8%) were HBsAg positive. HBV infection in girls was more than boys (11% to 5.6%). Among the types of mental retardation, children with cerebral palsy had the highest positive result for HBsAg. The most HBV infection (28.5%) was seen in children with longest duration of being institutionalized (10 to 11 years). Vaccinated children were more HBsAg positive (8.7%) than non-vaccinated children (5.3%). However, no significant relationship was observed between any of these factors and HBsAg positivity. Conclusion: Despite improvement of people’s health condition and implementation of HBV vaccination, the prevalence of HBV infection is high in institutionalized mentally retarded children, which highlights the need for active measures to reduce this infection among this high risk population.

Keywords: hepatitis B virus, HBV vaccine, intellectually disabled children, mentally retarded

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Authors: Marta Tryzna, Shahd Al Shammari

Abstract:

Though Modern Standard Arabic (MSA) is the only official language in GCC states, including Kuwait, and traditionally the preferred vehicle for literacy in the Arab countries, recent studies in Qatar and the UAE observe a growing role of English, particularly in literacy and knowledge transmission contexts. The present study examines the attitudes to Arabic and English and the use of both languages in literacy-related domains based on a sample of bilingual Arabic-English undergraduates (N=522) at a private university with EMI in Kuwait. The results indicate that Arabic (Kuwaiti dialect) is associated with familial interactions, Arabic-English bilingualism predominates in interactions with classmates, friends, on social media and at work, while English is prevalent in literacy-related contexts such as reading books, magazines, or online material, domains traditionally associated with MSA. Attitudes towards Arabic and English are equally positive according to the majority of the respondents, who report being comfortable expressing themselves and projecting their identity in both languages. No statistically significant differences were found comparing the importance of Arabic and English in the sample. Future trends were identified based on high agreement on the importance of speaking English with children and low agreement on speaking only Arabic at home. The study corroborates recently observed trends in the GCC favoring bilingualism across personal, academic and professional domains, with English becoming the preferred language of literacy among young bilingual Kuwaitis.

Keywords: bilingual, English, Arabic, EMI, identity

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Authors: M. I. Benamrani, H. Benamrani

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In the research to replace silicon and other thin-film semiconductor technologies and to develop long-term technology that is environmentally friendly, low-cost, and abundant, there is growing interest today given to organic materials. Our objective is to prepare polymeric layers containing metal particles deposited on a surface of semiconductor material which can have better electrical properties and which could be applied in the fields of nanotechnology as an alternative to the existing processes involved in the design of electronic circuits. This work consists in the development of composite materials by complexation and electroreduction of copper in a film of poly (pyrrole benzoic acid). The deposition of the polymer film on a monocrystalline silicon substrate is made by electrochemical oxidation in an organic medium. The incorporation of copper particles into the polymer is achieved by dipping the electrode in a solution of copper sulphate to complex the cupric ions, followed by electroreduction in an aqueous solution to precipitate the copper. In order to prepare the monocrystalline silicon substrate as an electrode for electrodeposition, an in-depth study on its surface state was carried out using photoacoustic spectroscopy. An analysis of the optical properties using this technique on the effect of pickling using a chemical solution was carried out. Transmission-photoacoustic and impedance spectroscopic techniques give results in agreement with those of photoacoustic spectroscopy.

Keywords: photoacoustic, spectroscopy, copper sulphate, chemical solution

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Authors: Moustafa Shawkey, Ahmed G. El-Deen, H. M. Mahmoud, M. M. Rashad

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Piezoelectric based cement nanocomposite is a promising technology for generating an electric charge upon mechanical stress of concrete structure. Moreover, piezoelectric nanomaterials play a vital role for providing accurate system of structural health monitoring (SHM) of the concrete structure. In light of increasing awareness of environmental protection and energy crises, generating renewable and green energy form cement based on piezoelectric nanomaterials attracts the attention of the researchers. Herein, we introduce a facial synthesis for bismuth ferrite nanoparticles (BiFeO3 NPs) as piezoelectric nanomaterial via sol gel strategy. The fabricated piezoelectric nanoparticles are uniformly distributed to cement-based nanomaterials with different ratios. The morphological shape was characterized by field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM) as well as the crystal structure has been confirmed using X-ray diffraction (XRD). The ferroelectric and magnetic behaviours of BiFeO3 NPs have been investigated. Then, dielectric constant for the prepared cement samples nanocomposites (εr) is calculated. Intercalating BiFeO3 NPs into cement materials achieved remarkable results as piezoelectric cement materials, distinct enhancement in ferroelectric and magnetic properties. Overall, this present study introduces an effective approach to improve the electrical properties based cement applications.

Keywords: piezoelectric nanomaterials, cement technology, bismuth ferrite nanoparticles, dielectric

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Authors: H. C. Chinwenyi, H. D. Ibrahim, J. O. Adekunle

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The incubation period is defined as the time from infection with a microorganism to development of symptoms. In this research, two disease models: one with incubation period and another without incubation period were studied. The study involves the use of a  mathematical model with a single incubation period. The test for the existence and stability of the disease free and the endemic equilibrium states for both models were carried out. The fourth order Runge-Kutta method was used to solve both models numerically. Finally, a computer program in MATLAB was developed to run the numerical experiments. From the results, we are able to show that the endemic equilibrium state of the model with incubation period is locally asymptotically stable whereas the endemic equilibrium state of the model without incubation period is unstable under certain conditions on the given model parameters. It was also established that the disease free equilibrium states of the model with and without incubation period are locally asymptotically stable. Furthermore, results from numerical experiments using empirical data obtained from Nigeria Centre for Disease Control (NCDC) showed that the overall population of the infected people for the model with incubation period is higher than that without incubation period. We also established from the results obtained that as the transmission rate from susceptible to infected population increases, the peak values of the infected population for the model with incubation period decrease and are always less than those for the model without incubation period.

Keywords: asymptotic stability, Hartman-Grobman stability criterion, incubation period, Routh-Hurwitz criterion, Runge-Kutta method

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Authors: Bin Bian, Liang Wang

Abstract:

A hydraulic spherical motion mechanism (HSMM) is proposed. Unlike traditional systems using serial or parallel mechanisms for multi-DOF rotations, the HSMM is capable of implementing continuous 2-DOF rotational motions in a single joint without the intermediate transmission mechanisms. It has some advantages of compact structure, low inertia and high stiffness. However, as HSMM is a nonlinear and multivariable system, it is very complicate to realize accuracy control. Therefore, an augmented active disturbance rejection controller (ADRC) is proposed in this paper. Compared with the traditional PD control method, three compensation items, i.e., dynamics compensation term, disturbance compensation term and nonlinear error elimination term, are added into the proposed algorithm to improve the control performance. The ADRC algorithm aims at offsetting the effects of external disturbance and realizing accurate control. Euler angles are applied to describe the orientation of rotor. Lagrange equations are utilized to establish the dynamic model of the HSMM. The stability of this algorithm is validated with detailed derivation. Simulation model is formulated in Matlab/Simulink. The results show that the proposed control algorithm has better competence of trajectory tracking in the presence of uncertainties.

Keywords: hydraulic spherical motion mechanism, dynamic model, active disturbance rejection control, trajectory tracking

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Authors: Young-Ji Kim, Jin-Hyeong Park, Hong-Seok Kim, Jung-Whan Chon, Kwang-Yeop Kim, Dong-Hyeon Kim, Il-Byeong Kang, Da-Na Jeong, Jin-Hyeok Yim, Ho-Seok Jang, Kwang-Young Song, Kun-Ho Seo

Abstract:

Stenotrophomonas maltophilia is one of the emerging opportunistic pathogens, and also known to have extensive drug resistance intrinsically including carbepenems which is last resort for most serious infections. One possible way for S. maltophilia to infect human is via wastewater treatment plant (WWTP). In the period between October 2016 and February 2017, effluent samples of WWTP from 3 different pig farms were collected once a month and screened for isolation of S. maltophilia. Total 16 strains of S. maltophilia were isolated and, the antibiotic susceptibility phenotypes were determined by Vitek 2 system for 16 antibiotics, ampicillin (AMP), amoxicillin/clavulanic acid (AMC), piperacillin/tazobactam (TZP), cefazolin (CZ), cefoxitin (FOX), cefotaxime (CTX), ceftazidime (CAZ), cefepime (FEP), aztreonam (AZT), ertapenem (ETP), imipenem (IMP), amikacin (AK), gentamicin (GN), ciprofloxacin (CIP), tigecycline (TGC) and trimethoprim/sulfamethoxazole (SXT). All isolates showed high resistance to AMP (100%), CZ (100%), FOX (100%), CTX (100%), CAZ (100%), FEP (94%), AZT (100%), ETP (100%), IMP (100%), AK (100%), GN (100%) whereas were susceptible to CIP (0%), TGC (0%), SXT (6%). All strains harbored at least one of the antibiotic resistance determinant such as spgM, rmlA, and rpfF. Some isolates had similar MLST (multilocus sequence typing) types with clinical isolates, suggesting WWTP could have potential role in the transmission of S. maltophilia to aquatic environment and, possibly, to humans.

Keywords: Stenotrophomonas maltophilia, Carbapenem resistance, waste water treatment plant, pig farm

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Authors: Qurat-ul-Ain, Humaira Mehmood

Abstract:

Background: HIV infection (a global pandemic) in pregnant women has turn out to be an emerging aspect of public health because of its role in the spread of HIV infection, predominantly among children. Aim: The aim was to analyze the trends of diagnosis with respect to gestational age and an overview of the mode of delivery over ten years. Methods: A retrospective data collection from clinical records of diagnosed HIV infected pregnant females attended at HIV antenatal clinic (special clinic), at Pakistan Institute of Medical Sciences, Islamabad, for various complaints during the period of 10 years from February 2007 to December 2016 was done. Results: A total of 113 pregnancies were reported with HIV infection in 10 years. Cases diagnosed at the 1st trimester (1-12 weeks) of pregnancy were (50.4%, 57/113), at the 2nd trimester (13-26 weeks) were (24.8%, 28/113), at the 3rd trimester (27-40+ weeks) were (24.7%, 28/113). Most deliveries were by caesarean section (53.1%, 60/113), elective caesarean sections were (58.3%, 35/60) and emergency caesarean sections were (41.6%,25/60). Vaginal deliveries were (26.5%, 30/113). Reported miscarriages were (17.7%, 20/113). Conclusion: At 1st trimester, 50% of the females were diagnosed with HIV infection, and 50% remained undiagnosed at their 1st trimester. Routine antenatal HIV testing throughout the country is vastly needed for timely diagnoses and prompt treatment(antiretroviral therapy), to suppress the virus, to reduce the risk of spread of HIV infection, to plan elective caesarean section delivery and to prevent mother-to-child transmission.

Keywords: gestational age, HIV infection, mode of delivery, pregnancy

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Authors: Alparslan A. Balta, Hilmi Yurdakul, Orkun Tunckan, Servet Turan, Arife Yurdakul

Abstract:

A silicon oxynitride (Si2N2O), the mineralogical name is “Sinoite”, reveals the outstanding physical, mechanical and thermal properties, e.g., good oxidation resistance at high temperatures, high fracture toughness with rod shape, high hardness, low theoretical density, good thermal shock resistance by low thermal expansion coefficient and high thermal conductivity. In addition, the orthorhombic crystal structure of Si2N2O allows accommodating the rare earth (RE) element atoms along the “c” axis due to existing large structural interstitial sites. Here, 0.02 to 0.12 wt. % Nd3+ doped Si2N2O samples were successfully synthesized by spark plasma sintering (SPS) method at 30MPa pressure and 1650oC temperature. Li2O was also utilized as a sintering additive to take advantage of low eutectic point during synthesizing. The specimens were characterized in detail by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and cathodoluminescence (CL) in SEM and photoluminescence (PL) spectroscopy. Based on the overall results, the Si2N2O phase was obtained above 90% by the SPS route. Furthermore, Nd3+: Si2N2O samples showed a very broad intense emission peak between 400-700 nm, which corresponds to white color. Therefore, this material can be considered as a promising candidate for white light-emitting diodes (WLEDs) purposes. This study was supported by TUBITAK under project number 217M667.

Keywords: neodymium, oxynitride, Si₂N₂O, WLEDs

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