Synthesis, structural characterization, and optical properties of PVA/MnO2 materials for optoelectronics applications

Norah A. M. Alsaif,A. Atta,E. Abdeltwab,M. M. Abdel‑Hamid 한국고분자학회 2024 Macromolecular Research Vol.32 No.1

In this study, polyvinyl alcohol (PVA) was mixed with concentration of 5%, 7.5%, and 10% of manganese dioxide ( MnO2) to form PVA/MnO2 films using solution cast approach method. The X-ray diffraction (XRD) verified that the nanomaterials films were successfully fabricated. The scanning electron microscope (SEM) illustrates the uniform MnO2 dispersion within the PVA host matrix. Additionally, the influence of MnO2 on the optical properties is recorded. The refractive index (n0) is improved by adding MnO2, from 1.29 for PVA to 1.87 for PVA/5%MnO2 and 2.86 for PVA/10%MnO2. The PVA had a dispersion energy of 2.53 eV, while PVA with 5% MnO2 had 4.86 eV, PVA with 7.5% MnO2 had 5.74 eV, and PVA with 10%MnO2 had 7.12 eV. In addition, the oscillation energy E0 decreased from 3.79 for PVA to 1.94, 1.72, and 0.99 eV, respectively for PVA/5%MnO2, PVA/7.5%MnO2, and PVA/10%MnO2. It is evident from the data that the incorporation of MnO2 to the PVA polymer alters its optical properties. This proved the existence of strong interactions of PVA and MnO2 due to the modification of the PVA/MnO2 electronic structure. Moreover, the plasma frequency W p value increased from 0.79 × 1013 s− 1 for PVA to 2.06 × 1013 s− 1 for PVA/10%MnO2. These shifts in W p provided the polarization is modified for the PVA/MnO2. The results obtained in this study provide evidence of the advantages associated with the utilization of MnO2 nanoparticles as a filler of improved polymeric structures. These findings also propose the potential suitability of MnO2 nanoparticles for application in the field of optics and electronic devices.

Automatic Determination of the Number of Clusters for Semi-Supervised Relational Fuzzy Clustering

Norah Ibrahim Fantoukh,Mohamed Maher Ben Ismail,Ouiem Bchir 한국지능시스템학회 2020 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.20 No.2

Semi-supervised clustering relies on both labeled and unlabeled data to steer the clustering process towards optimal categorization and escape from local minima. In this paper, we propose a novel fuzzy relational semi-supervised clustering algorithm based on an adaptive local distance measure (SSRF-CA). The proposed clustering algorithm utilizes side-information and formulates it as a set of constraints to supervise the learning task. These constraints are expressed using reward and penalty terms, which are integrated into a novel objective function. In particular, we formulate the clustering task as an optimization problem through the minimization of the proposed objective function. Solving this optimization problem provides the optimal values of different objective function parameters and yields the proposed semi-supervised clustering algorithm. Along with its ability to perform data clustering and learn the underlying dissimilarity measure between the data instances, our algorithm determines the optimal number of clusters in an unsupervised manner. Moreover, the proposed SSRF-CA is designed to handle relational data. This makes it appropriate for applications where only pairwise similarity (or dissimilarity) information between data instances is available. In this paper, we proved the ability of the proposed algorithm to learn the appropriate local distance measures and the optimal number of clusters while partitioning the data using various synthetic and real-world benchmark datasets that contain varying numbers of clusters with diverse shapes. The experimental results revealed that the proposed SSRF-CA accomplished the best performance among other state-of-the-art algorithms and confirmed the outperformance of our clustering approach.

Preparation and Non Isothermal Crystallization Kinetic of Acetylsalicylic Acid-Poly(vinylalcohol-co-ethylene) Blend. Application in Drug Delivery Domain

Norah Mubarak Alotaibi,Taieb Aouak 한국고분자학회 2013 Macromolecular Research Vol.21 No.7

A series of acetylsalicylic acid-poly(vinylalcohol-co-ethylene) blends (AcSa/PVAE) of different compositions were prepared by dissolution and solvent evaporation then characterized by the solubility test, differential scanning calorimetry (DSC), X-ray diffractometer (XRD) and by scanning electron microscopy (SEM)analyses. The results revealed that AcSa was perfectly soluble in PVAE up to a certain composition. A non-isothermal study of the crystallization kinetic of AcSa/PVAE materials was carried out by the DSC method. It was observed that the Ozawa equation perfectly describes the primary process of non-isothermal crystallization of this material. There is a strong dependence of AcSa/PVAE composition on the crystallization parameters. In general,at any cooling rate the variation in t1/2 of crystallization vs. the AcSa/PVAE composition passed by a minimum then a maximum of 7 and 5 wt% of AcSa, respectively. The crystallization activation energy (Ea) calculated from the Kissinger model reached a maximum when the concentration of AcSa in the AcSa/PVAE system was 8.5 wt%. The release dynamic of AcSa from AcSa/PVAE material was tested at body temperature during 92 h. On the light of the data obtained, it was found that at pH 5 and 7, AcSa/PVAE 15 presented the best performance because this material was capable of releasing more than 50 wt% of the AcSa amount uniformly (1.30±0.8 wt%/h) during 38-39 h.

Genome editing reveals a role for OCT4 in human embryogenesis

Fogarty, Norah M. E.,McCarthy, Afshan,Snijders, Kirsten E.,Powell, Benjamin E.,Kubikova, Nada,Blakeley, Paul,Lea, Rebecca,Elder, Kay,Wamaitha, Sissy E.,Kim, Daesik,Maciulyte, Valdone,Kleinjung, Jens,K Macmillan Publishers Limited, part of Springer Nat 2017 Nature Vol.550 No.7674

<P>Despite their fundamental biological and clinical importance, the molecular mechanisms that regulate the first cell fate decisions in the human embryo are not well understood. Here we use CRISPR-Cas9-mediated genome editing to investigate the function of the pluripotency transcription factor OCT4 during human embryogenesis. We identified an efficient OCT4-targeting guide RNA using an inducible human embryonic stem cell-based system and microinjection of mouse zygotes. Using these refined methods, we efficiently and specifically targeted the gene encoding OCT4 (POU5F1) in diploid human zygotes and found that blastocyst development was compromised. Transcriptomics analysis revealed that, in POU5F1-null cells, gene expression was downregulated not only for extra-embryonic trophectoderm genes, such as CDX2, but also for regulators of the pluripotent epiblast, including NANOG. By contrast, Pou5f1-null mouse embryos maintained the expression of orthologous genes, and blastocyst development was established, but maintenance was compromised. We conclude that CRISPR-Cas9-mediated genome editing is a powerful method for investigating gene function in the context of human development.</P>

재사용이 가능한 MFB로부터 Aromatic Ester가 도입된 4,4’-Di((E)-styryl)-1,1’-biphenyl의 골격을 갖는 새로운 Fluorescent Whitening Agent의 개발 연구

( Alkhalaf Norah. S. ),김석찬 ( Seok Chan Kim ) 한국공업화학회 2018 공업화학 Vol.29 No.3

DMT 생산과정의 부산물로서 폐기 처리되어 왔던 methyl 4-formylbenzoate (MFB)를 출발 물질로 하여 고급 형광 증백제 family와 동일한 4,4’-di((E)-styryl)-1,1’-biphenyl 기본 골격을 갖고 aromatic ester가 도입된 새로운 형광 증백제 (fluorescent whitening agent) 후보 물질 6종을 합성하였다. 후보 물질 6종은 MFB 및 그의 유도체와 tetraethyl biphenyl-4,4’-diylbis(methylene)diphosphonate와 Wittig-Horner 반응을 이용하여 합성하였다. 합성된 6종에 대하여 형광증 백제로의 가능성을 확인하기 위하여 UV 스펙트럼을 기록하여 흡광 계수를 얻었으며, 6종 모두 전반적으로 기존 상용제품(log ε 4.85)과 유사한 몰 흡광 계수(log ε 4.59~5.00)를 보여주고 있다. 특별히 화합물 디메톡시 페닐그룹을 갖는 16, 17은 기존 상용 제품보다 우수한 몰흡광 계수를 나타내고 있어 상용화를 위한 현장 테스트를 진행할 예정이다. Methyl 4-formylbenzoate (MFB), a by-product of the DMT production process, which has been disposed, was used as a starting material for the synthesis of six new fluorescent whitening agent’s candidates with 4,4’-di((E)-styryl)-1,1’-biphenyl skeleton attached with an aromatic ester, the same as that of the commercial product family. All candidates were synthesized by the reaction of MFB, and its derivatives with tetraethyl biphenyl-4,4’-diylbis(methylene)diphosphonate using Wittig-Horner reaction. UV spectra for all candidates were recorded and the data were used for calculating the molar absorptivity in order to confirm the usability as a fluorescent whitening agent. All of them showed overall molar extinction coefficients (log ε 4.59~5.00) similar to those of conventional commercial products (log ε 4.85). In particular, compounds 16 and 17 having a dimethoxyphenyl group exhibited a molar extinction coefficient superior to those of conventional commercial products, and thus a field testing for commercialization will be conducted.

Assessment of performance of machine learning based similarities calculated for different English translations of Holy Quran

Al Ghamdi, Norah Mohammad,Khan, Muhammad Badruddin International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.4

This research article presents the work that is related to the application of different machine learning based similarity techniques on religious text for identifying similarities and differences among its various translations. The dataset includes 10 different English translations of verses (Arabic: Ayah) of two Surahs (chapters) namely, Al-Humazah and An-Nasr. The quantitative similarity values for different translations for the same verse were calculated by using the cosine similarity and semantic similarity. The corpus went through two series of experiments: before pre-processing and after pre-processing. In order to determine the performance of machine learning based similarities, human annotated similarities between translations of two Surahs (chapters) namely Al-Humazah and An-Nasr were recorded to construct the ground truth. The average difference between the human annotated similarity and the cosine similarity for Surah (chapter) Al-Humazah was found to be 1.38 per verse (ayah) per pair of translation. After pre-processing, the average difference increased to 2.24. Moreover, the average difference between human annotated similarity and semantic similarity for Surah (chapter) Al-Humazah was found to be 0.09 per verse (Ayah) per pair of translation. After pre-processing, it increased to 0.78. For the Surah (chapter) An-Nasr, before preprocessing, the average difference between human annotated similarity and cosine similarity was found to be 1.93 per verse (Ayah), per pair of translation. And. After pre-processing, the average difference further increased to 2.47. The average difference between the human annotated similarity and the semantic similarity for Surah An-Nasr before preprocessing was found to be 0.93 and after pre-processing, it was reduced to 0.87 per verse (ayah) per pair of translation. The results showed that as expected, the semantic similarity was proven to be better measurement indicator for calculation of the word meaning.

Structural, dielectric and magnetic properties of cobalt based spinel ferrites

Rabia Qindeel,Norah H. Alonizan 한국물리학회 2018 Current Applied Physics Vol.18 No.5

CoYbxFe2-xO4 (x=0.00, 0.025, 0.05, 0.075, 0.10) spinel ferrites were synthesized by co-precipitation technique. Structural, dielectric and magnetic properties were measured. X-ray diffraction analysis showed that all the prepared spinel ferrites possessed cubic spinel structure. Dielectric constant, AC conductivity and dielectric loss decreased with the addition of rare earth ions. The impedance analysis explained the role of grains and grain boundaries with in prepared samples. Cole-Cole plots helped to measure the values of grains and grain boundary's resistance. The magnetic properties proved the soft nature of these ferrites. Saturation magnetization and remanence decreased while coercivity was enhanced with the addition of ytterbium concentration. All these parameters suggested that these prepared samples might be suitable for high frequency applications.

Normal Age-Adjusted Sagittal Spinal Alignment Is Achieved with Surgical Correction in Adolescent Idiopathic Scoliosis

Subaraman Ramchandran,Norah Foster,Akhila Sure,Thomas J. Errico,Aaron J. Buckland 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.5

Study Design: Retrospective analysis. Purpose: Our hypothesis is that the surgical correction of adolescent idiopathic scoliosis (AIS) maintains normal sagittal alignment as compared to age-matched normative adolescent population. Overview of Literature: Sagittal spino-pelvic alignment in AIS has been reported, however, whether corrective spinal fusion surgery re-establishes normal alignment remains unverified. Methods: Sagittal profiles and spino-pelvic parameters of thirty-eight postsurgical correction AIS patients ≤21 years old without prior fusion from a single institution database were compared to previously published normative age-matched data. Coronal and sagittal measurements including structural coronal Cobb angle, pelvic incidence, pelvic tilt, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, C2–C7 cervical lordosis, C2–C7 sagittal vertical axis, and T1 pelvic angles were measured on standing full-body stereoradiographs using validated software to compare preoperative and 6 months postoperative changes with previously published adolescent norms. A sub-group analysis of patients with type 1 Lenke curves was performed comparing preoperative to postoperative alignment and also comparing this with previously published normative values. Results: The mean coronal curve of the 38 AIS patients (mean age, 16±2.2 years; 76.3% female) was corrected from 53.6° to 9.6° (80.9%, p <0.01). None of the thoracic and spino-pelvic sagittal parameters changed significantly after surgery in previously hypo- and normo-kyphotic patients. In hyper-kyphotic patients, thoracic kyphosis decreased (p =0.003) with a reciprocal decrease in lumbar lordosis (p =0.01), thus lowering pelvic incidence-lumbar lordosis mismatch mismatch (p =0.009). Structural thoracic scoliosis patients had slightly more thoracic kyphosis than age-matched patients at baseline and surgical correction of the coronal plane of their scoliosis preserved normal sagittal alignment postoperatively. A sub-analysis of Lenke curve type 1 patients (n=24) demonstrated no statistically significant changes in the sagittal alignment postoperatively despite adequate coronal correction. Conclusions: Surgical correction of the coronal plane in AIS patients preserves sagittal and spino-pelvic alignment as compared to age-matched asymptomatic adolescents.

Facile fabrication of ternary CuO/CuS/ZnS for photodegradation of methylene blue

Abudllah Muhammad,Al Huwayz Maryam,Alwadai Norah,Manzoor Sumaira,Nisa Mehar Un,John Peter,Ghori Muhammad Ishfaq,Aman Salma,Al-Buriahi M. S.,Ashiq Muhammad Naeem 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.3

Synthetic dyes play a vital role in our daily life because they are utilized in products ranging from clothing to leather acces- sories. Unfortunately, these carcinogenic dyes are discharged into water streams any prior process considering the health problems in aquatic life and human beings. It is mandatory to separate noxious materials from wastewater. Semiconductors are viewed as a viable possibility for photocatalytic mineralization of noxious dyes. Herein, facile in situ hydrothermal approach (HT) was utilized for the fabrication of CuO, CuS ZnS, and their ternary CuO/CuS/ZnS nanocomposite. The fab- ricated CuO/CuS/ZnS nanocomposites were analysed through powder X-ray diff raction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope equipped with energy-dispersive X-ray (SEM–EDX), and ultraviolet– visible spectroscopy (UV–Vis). Moreover, the optical investigation manifested the bandgap energy value of copper oxide, copper sulphides, zinc sulphides, and ternary CuO/CuS/ZnS nanocomposite, corresponding to 2.63, 3.1, 4.51, and 2.2 eV, respectively, which was estimated from absorption spectrum. Subsequently, the photocatalytic results of CuO, CuS, ZnS, and ternary CuO/CuS/ZnS nanocomposite against methylene blue (MB) dye were 71%, 42%, 45%, and 96%, respectively. The photocatalytic scheme showed the role of hydroxyl radicals and electrons in the photodegradation reaction. Our fi nding suggests that the fabricated nanocomposite shows superior photocatalytic efficiency towards mineralization of methylene blue which can be used for commercial applications.

Evaluation of Official Healthcare Informatics Applications in Saudi Arabia and their Role in Addressing COVID-19 Pandemic

Nouf Alassaf,Sulaiman Bah,Fatima Almulhim,Norah AlDossary,Munirah Alqahtani 대한의료정보학회 2021 Healthcare Informatics Research Vol.27 No.3

Objectives: The purpose of this study was to examine official healthcare informatics applications in Saudi Arabia in the context of their role in addressing the coronavirus disease 2019 (COVID-19) pandemic. Methods: This is a case study of official healthcare informatics programs and applications (apps) developed in Saudi Arabia before and during the COVID-19 pandemic. The qualitative content analysis (QCA) method was used. Data collection consisted of two components: a desktop review of documents and actual testing of the programs. According to the QCA method, we developed a matrix for abstracting information on different apps and programs in order to categorize the data. The compilation of information and discussion were based on information summarized in the matrix. Results: Six apps in total were developed before the COVID-19 pandemic. With the advent of the COVID-19 pandemic, three of the apps, SEHA, Mawid, and Sehaty were modified to address different aspects of the pandemic. Both SEHA and Mawid included information about COVID-19 awareness. During the COVID-19 pandemic, three official apps were developed: Tawakkalna, Tetamman, and Tabaud. The Tawakkalna app is mandatory for all citizens and residents to activate when visiting stores and institutions. It has a wide range of COVID-19 and other health-related functions. The Tetamman app provides COVID-19 test results and allows one to check his or her daily symptoms. It also has an educational content library and provides alerts. The Tabaud app notifies individuals if they have been exposed to COVID-19. The features, advantages, and disadvantages of all of the apps were examined. Conclusions: Overall, there were more strengths than shortcomings in the role played by healthcare informatics in the handling of the COVID-19 pandemic in Saudi Arabia.