Dealing with Anxiety in Foreign Language Learning Classroom

Anxiety is a major factor that handicap learners’ cognition in learning. Learners in foreign language learning (FL) suffer from anxiety due to various reasons. Studies found that higher level of anxiety affects the learning process and lowers down learning motivation. In light of research literature, this paper aims at finding out the most serious reasons of FL learning anxiety and its effects on learners’ FL learning process. The study draws on the existing scholarship in the theorizing for anxiety in FL learning settings. The study followed the qualitative method of research. The findings reveal that anxiety negatively affects the learning and achievements of students. This study also suggests effective techniques to help learners get rid of FL learning anxiety in classroom situation

Synthesis of some new antipyrine-thiophene hybrids and their evaluations as antioxidant and antibacterial agents

ABSTRACT. A novel series of antipyrinyl thienyl ketones 4a-c, 7a-c, 10a-c, and 13a-b was chemically synthesized through the cyclocondensation of 4-chloroacetylantipyrine with various 2-substituted-thioacetanilide scaffolds, including 3-arylazo-4-mercapto-4-phenylamino-buten-2-ones, ethyl 2-arylazo-3-mercapto-3-phenylamino-acrylate, 2-cyano-3-mercapto-3-(phenylamino)-N-arylacrylamide, 4-mercapto-4-(phenylamino)but-3-en-2-one, and/or ethyl-3-mercapto-3-(phenylamino)acrylate. Indeed, the reaction of 4-chloroacetylantipyrine with 4-hydroxybenzaldehyde followed by refluxing with 2-cyanoacetohydrazide yielded 2-cyano-N'-(4-(2-(antipyrin-4-yl)-2-oxoethoxy)benzylidene)-acetohydrazide 17 as a building compound, which was used consequentially to synthesize a set of new antipyrinyl thienyl hybrids 19a-d. The chemical structures of newly synthesised compounds were unambiguously confirmed using extensive elemental and spectral data analyses. The newly synthesized compounds were screened for their antioxidant and antimicrobial activities. Compared to the test reference (Ascorbic acid, 88.0%), the antipyrinyl thienyl ketones 13a and 13b substituted with methyl and/or hydroxyl groups at the thiophene ring system displayed excellent antioxidant properties, 87.8% and 87.2%, respectively. Additionally, antipyrinyl thienyl ketones 13a and 13b showed high antibacterial activities, and their relative activity index (which ranges from 68% to 91.7%) was close to that of a reference compound, Ampicillin.   KEY WORDS: 4-Chloroacetylantipyrine, Thioacetanilide, Antipyrinyl thienyl ketones, Antioxidant, Antimicrobial   Bull. Chem. Soc. Ethiop. 2023, 37(1), 123-140.                                                              a DOI:https://dx.doi.org/10.4314/bcse.v37i1.1

Comparative Amino Acids Studies on Phac Synthases and Proteases as Well as Establishing a New Trend in Experimental Design

ABSTRACT: A question addressed in this study is: why similar enzymes are classified into different subclasses? As an example, PhaC synthases are classified according to four different classes (I, II, III and IV). To answer this question we proposed that besides the catalytic residues, the overall amino acids (AAs) present are responsible for the differences observed. The AAs’ composition affects the structure/function/substrate specificity (SFS) of these enzymes. The differences between the classes in various PhaC synthases and proteases were analysed to support our argument. Homology and phylogenic tree of some selected PhaC synthases of different strains (representing the four classes) were demonstrated. The properties of a specific class of enzyme could not be changed into those of another by changing the catalytic residues. Moreover, these differences could not be detected from the proteins’ 3D structures, despite clear differences at the AAs level. Another question was also addressed: could we benefit from the various existing protein databases in the field of biotechnology? To answer this, we introduced a model for an Experimental Design based on the information in the protein database (for strains available in our lab) regarding their ability to degrade castor oil. Two enzymes in the phenol degradation pathway, phenol 2-monooxygenase and catechol 1,2-dioxygenase, and a lipase enzyme were analysed. These enzymes were screened and analysed according to the BLAST-protein database and BRENDA. The comprehensive enzyme information system compared six strains against each other, including: Pseudomonas aeruginosa, Bacillus subtilis, Bacillus pumilus, Bacillus thuringiensis, Bacillus licheniformis, and Geobacillus stearothermophilus. Only P. aeruginosa proved to have the three required enzymes and was suitable for the production of lipases from castor oil (crude castor oil is usually contaminated with phenol) as indicated by the databases. In addition, in vivo castor oil degradation and in vitro lipase enzyme activity were analysed. The apparent lipase activity was 1070 Units/ml. Therefore, this new strategy is recommended to better understand the SFS as well as for using protein database in an Experimental Design. ABSTRAK: Kajian ini berkisar mengenai soalan: mengapa enzim yang sama diklassifikasikan kepada subkumpulan yang berbeza? Contohnya sintasis PhaC dikelaskan kepada empat kumpulan berbeza (I, II, III dan IV). Bagi menjawab soalan ini selain hipotesis katalitik residue diperkenalkan, faktor yang bertanggungjawab adalah asid amino (AAs) secara keseluruhannya. Komposisi AAs memberi kesan kepada struktur/fungsi/spesifikasi substrat (SFS) enzim-enzim ini. Perbezaan di antara kumpulan dalam pelbagai sintasis PhaC dan proteases telah dianalisis bagi menyokong hujah ini. Homologi dan asas phylogenic bagi sintasis PhaC tertentu yang berbeza strains (mewakili empat kumpulan) telah ditunjukkan. Sifat-sifat tidak boleh ditukarkan dengan menukarkan katalitik residue dari satu kepada yang lain. Tambahan pula, kelainannya tidak boleh dikesan dari struktur 3D protein, walaupun perbezaan yang nyata pada peringkat AAs. Soalan lain yang berkisar adalah: Adakah kita mendapat faedah dari pelbagai pengkalan data dalam bidang bioteknologi? Bagi menjawab soalan ini, model Rekabentuk Eksperimen telah diperkenalkan yang berasaskan maklumat pengkalan data protein bagi strains di makmal kami yang boleh degradasi minyak castor. Dua enzim dalam degradasi fenol telah dianalisis, fenol 2-monooxigenas dan catechol 1,2-dioxygenas serta enzim lipas. Enzim-enzim ini telah disaringkan dan dianalisis dengan merujuk kepada pengkalan data protein-BLAST dan BRENDA. Sistem maklumat enzim secara komprehensif terhadap enam strains termasuk Pseudomonas aeruginosa, Bacillus subtilis, Bacillus pumilus, Bacillus thuringiensis, Bacillus licheniformis dan Geobacillus stearothermophilus. Hanya P. Aeruginosa terbukti mempunyai tiga enzim dan sesuai bagi penghasilan lipase dari minyak kastor (minyak kastor mentah selalunya tercemar dengan fenol) seperti yang ditunjukkan dari pengkalan data. Degradasi minyak kastor in vivo dan aktiviti enzim lipase in vitro telah dilaksanakan. Aktiviti lipase jelas adalah 1070 Units/ml. Kami mencadangkan menggunakan strategi ini bagi memahami SFS serta pengkalan data protein dalam Rekabentuk Eksperimen. KEYWORDS: amino acids; model; PhaC synthase; protease; lipase; experimental desig

Inkjet printing of polyimide insulators for the 3D printing of dielectric materials for microelectronic applications

In this article, we report the first continuous fabrication of inkjet-printed polyimide films, which were used as insulating layers for the production of capacitors. The polyimide ink was prepared from its precursor poly(amic) acid, and directly printed on to a hot substrate (at around 160 °C) to initialize a rapid thermal imidization. By carefully adjusting the substrate temperature, droplet spacing, droplet velocity, and other printing parameters, polyimide films with good surface morphologies were printed between two conducting layers to fabricate capacitors. In this work, the highest capacitance value, 2.82 ± 0.64 nF, was achieved by capacitors (10 mm × 10 mm) with polyimide insulating layers thinner than 1 μm, suggesting that the polyimide inkjet printing approach is an efficient way for producing dielectric components of microelectronic devices. © 2016 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43361

Programmable Beam-Steering Capabilities Based on Graphene Plasmonic THz MIMO Antenna via Reconfigurable Intelligent Surfaces (RIS) for IoT Applications

The approaching sixth-generation (6G) communication network will modernize applications and satisfy user demands through implementing a smart and reconfigurable system with a higher data rate and wider bandwidth. The controllable THz waves are highly recommended for the instantaneous development the new technology in wireless communication systems. Recently, reconfigurable intelligent surfaces (RIS), also called codded/tunable programmable metasurfaces, have enabled a conspicuous functionality for THz devices and components for influencing electromagnetic waves (EM) such as beam steering, multi-beam-scanning applications, polarization variation, and beam focusing applications. In this article, we proposed a graphene plasmonic two-port MIMO microstrip patch antenna structure that operates at a 1.9 THz resonance frequency. An E-shape MTM unit cell is introduced to enhance the isolation of the antenna from −35 dB to −54 dB. An implementation of controllable and reconfigurable surfaces based on graphene meta-atoms (G-RIS) placed above the radiating patches with a suitable separated distance to control the radiated beam to steer in different directions (±60°). The reconfigurable process is carried out via changing the (ON/OFF) meta-atoms states to get a specific code with a certain beam direction. The gain enhancement of the antenna can be implemented through an artificial magnetic conductor (AMC) based on graphene material. The G-AMC layer is located underneath the (MIMO antenna, G-RIS layer) to improve the gain from 4.5 dBi to 10 dBi. The suggested antenna structure results are validated with different techniques CST microwave studio and ADS equivalent circuit model. The results have asymptotic values. So, the proposed design of the MIMO antenna that is sandwiched between G-RIS and G-AMC is suitable for IoT applications

Combined inkjet printing and infrared sintering of silver nanoparticles using a swathe-by-swathe and layer-by-layer approach for 3-dimensional structures

Despite the advancement of additive manufacturing (AM)/3-dimensional (3D) printing, single-step fabrication of multifunctional parts using AM is limited. With the view of enabling multifunctional AM (MFAM), in this study, sintering of metal nanoparticles was performed to obtain conductivity for continuous line inkjet printing of electronics. This was achieved using a bespoke three dimensional (3D) inkjet-printing machine, JETx®, capable of printing a range of materials and utilizing different post processing procedures to print multi-layered 3D structures in a single manufacturing step. Multiple layers of silver were printed from an ink containing silver nanoparticles (AgNPs) and infra-red sintered using a swathe-by-swathe (SS) and layer-by-layer sintering (LS) regime. The differences in the heat profile for the SS and LS was observed to influence the coalescence of the AgNPs. Void percentage of both SS and LS samples was higher towards the top layer than the bottom layer due to relatively less IR exposure in the top than the bottom. The results depicted a homogeneous microstructure for LS of AgNPs and showed less deformation compared to the SS. Electrical resistivity of the LS tracks (13.6 ± 1μΩ cm) was lower than the SS tracks (22.5 ± 1 μΩ cm). This study recommends the use of LS method to sinter the AgNPs to obtain a conductive track in 25% less time than SS method for MFAM

Review for the management of vitamin B12 deficiency in diabetic patients on metformin

Long-term usage of Metformin is associated with lower serum vitamin B12 levels. The lower than normal levels could worsen neurological complications of diabetes, including diabetic neuropathy and poor cognition. Guidelines advise periodic monitoring of vitamin B12 but do not specify frequency, treatment targets or treatment modality. This commentary aims to review the prevalence and the severity of the presentation and to provide evidence-based answers to those clinical questions not answered by current guidelines

Investigation and application of Bacillus pumilus QBP344-3 in the control of Aspergillus carbonarius and ochratoxin A contamination

This study was designed to investigate the antifungal activity of Bacillus pumilus 344-3 against toxigenic fungi. In vitro co-incubation assay revealed that A. carbonarius AC82, A. niger AN8 and P. digitatum PD43 are most sensitive fungi to bacterial antifungal compounds with zone of inhibition of 29.2 mm, 27.7 mm and 27.1 mm, respectively. The addition of Bacillus pumilus 344-3 culture supernatant at low concentration in the fungal growth medium stimulated A. carbonarius biomass, but inhibited ochratoxin A (OTA) synthesis significantly (p ≤ 0.05). Conidial germination of A. carbonarius was not affected in a medium containing 10% and 20% of the bacterial culture supernatant, while it was completely inhibited in 100% bacterial extract. Storage of bacterial culture supernatant at temperature ranging from −20 °C to 100 °C for 1 h, didn't affect its antifungal potential. In vivo application of bacterial extract on the maize kernels, showed 95% protection against A. carbonarius infection. Application of B. pumilus 344-3 culture supernatant on the surface of maize kernels provided 99% reduction in OTA production potential of A. carbonarius AC82. Because of its strong activities against the growth of A. carbonarius AC82 and OTA-synthesis, B. pumilus 344-3 can be considered as a very promising biocontrol agent