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Social media, such as Twitter, have skyrocketed in popularity over the past few years. In fact, social media have been widely used by students and instructors as teaching and learning tools. In response to the increasing use of Twitter in the educational field, we have collected ten studies between 2011 to 2020 in order to assess the relationship between social media, specifically Twitter, and students' engagement and grades. We have conducted a meta-analysis to provide empirical evidence concerning the impact of Twitter on student engagement and achievement. Furthermore, we have utilized the manual approach of content analysis in order to code these articles. Overall, metadata suggests that Twitter has a stronger impact on student engagement than on grades. Nevertheless, its impact is not necessarily positive, especially on grades.

Scientometric studies play a crucial role in quantitatively assessing the impact and quantity of scholarly articles, providing a basis for policy-making and informed decision-making processes. Given the ongoing transformation within the Saudi scientific community across various domains, it is essential to establish a baseline for high-quality endodontic research. A comprehensive search in the PubMed database, using the keywords [“Saudi” OR “Saudi Arabia”] within the time frame of 2014 to 2021. The screening process involved evaluating the title and abstract of each article, with only those classified as endodontic articles included for analysis in this study. The analysis included factors such as the type of paper, the authors, the citations, and the year of publication. Featuring one or more authors affiliated with a Saudi dental institution, 70 papers were specifically categorized as endodontic papers. The most prevalent type of paper was case reports, accounting for 27 articles (28%), followed by literature reviews with 13 articles (18%). The number of authors ranged from one to ten, with a general trend of increasing publication rates over the years. In terms of citations, only four papers received more than 20 citations, while the majority of papers garnered between one and ten citations. Most articles in the field of endodontics exhibited low-level evidence. Therefore, it is recommended that the quality of research output and evidence be enhanced.

Many higher educational institutions have adopted Learning Management Systems. Blackboard, characterized as one of the technological educational systems, is one of the leading and extensive Learning Management Systems adopted by most universities. However, literature showed that a missing link appears between Blackboard adoption and Blackboard poor usage in teaching and learning. Therefore, this study aims to gauge the perceptions of students toward using Blackboard Collaborate in learning English as a Foreign Language academic writing. Online survey was conducted and distributed to 248 respondents. This study is quantitative in nature, employing Technology Acceptance Model theory to check Learning Management System acceptance at Saudi Electronic University in Saudi Arabia. The findings showed that all the constructs were relatively strong and had positive relationships; they were correlated with each other and the whole six hypotheses were supported as well. In this paper, the proposed model indicates that Attitude toward Use is the strongest predictor of Behaviour Intention. This study offers implications for further studies.

Peptic ulcer disease (PUD), often caused by Helicobacter pylori infection, is a prevalent gastrointestinal condition characterized by the erosion of the gastric or duodenal mucosal lining. H. pylori adheres to gastric epithelial cells, secreting toxins and disrupting the stomach's defenses. H. pylori relies on various receptors to establish infection, making these molecules attractive therapeutic targets. This study aimed to develop novel anti-ulcer compounds by combining benzothiazole, pyrazoline, and chalcone pharmacophores. A series of chalcone derivatives 4a-c were synthesized via Claisen-Schmidt condensation and characterized using spectroscopic techniques such as FT-IR, NMR and elemental analysis. The DFT calculations, using B3LYP method with 6-311G basis set, revealed the p-tolyl derivative 4b exhibited the highest thermal stability while the p-bromophenyl derivative 4c showed the lowest stability but highest chemical reactivity. The HOMO-LUMO energy gaps as well as the dipole moments decreased in the order: 4b > 4a > 4c, reflecting a similar reactivity trend. Molecular docking showed ligands 4a-c bound effectively to the H. pylori urease enzyme, with docking scores from −5.3862 to −5.7367 kcal/mol with superior affinity over lansoprazole. Key interactions involved hydrogen bonds and hydrophobic pi-hydrogen bonds with distances ranging 3.46–4.34 Å with active site residues ASN666, SER714 and ASN810. The combined anti-inflammatory, antimicrobial, and H. pylori anti-adhesion properties make these novel chalcones promising PUD therapeutic candidates.

This study investigated Saudi EFL university students' perceptions toward the development of reading comprehension through e-learning sessions. A cross-sectional questionnaire was utilized and distributed to a sample of 140 participants at Saudi Electronic University. Descriptive statistics, independent sample paired t-test and one-way ANOVA were used to analyze the data. The findings revealed that EFL university students had positive perceptions of the use of online sessions to practice the reading comprehension skill. The majority agreed that reading comprehension strategies such as skimming and scanning were more appropriate to online sessions. E-learning helped these students to be more motivated and created an atmosphere conducive to independent learning. The participants appreciated the role of online sessions in enhancing their reading comprehension skills and facilitating the level of difficulty of any reading passage. Significant differences were identified relating to the respondents' gender and academic year. Female students were more satisfied with e-learning than male students. It is recommended that in light of the rapid growth of e-learning in Saudi Arabia, educational institutions should provide online learning programs and develop well-structured courses for e-learning implementation.

This study aims to examine the effectiveness of online problem-based learning (PBL) tasks on problem-solving ability (PSA) and programming skills of secondary school students. A quantitative research design of a quasi-experimental research was adopted in this study. A purposive non-random sampling method was used to select two schools. Then, a clustered random sampling technique was carried out to select four classes, consisting of 120 students. The classes were divided equally into online PBL and non-online PBL. A problem-solving inventory questionnaire was used to measure PSA before and after the treatment, and pre-post performance tests were used to assess students' performance. The students underwent 8 weeks of learning tasks by using online PBL via Facebook groups. The findings from this study proved that online PBL improved students' PSA, and their higher-order thinking skills, and helped them to perform better in learning programming by using Facebook for interaction and participation in the online discussion with a facilitator and peers.

This study aims to examine the effectiveness of online problem-based learning (PBL) tasks on problem-solving ability (PSA) and programming skills of secondary school students. A quantitative research design of a quasi-experimental research was adopted in this study. A purposive non-random sampling method was used to select two schools. Then, a clustered random sampling technique was carried out to select four classes, consisting of 120 students. The classes were divided equally into online PBL and non-online PBL. A problem-solving inventory questionnaire was used to measure PSA before and after the treatment, and pre-post performance tests were used to assess students’ performance. The students underwent 8 weeks of learning tasks by using online PBL via Facebook groups. The findings from this study proved that online PBL improved students’ PSA, and their higher-order thinking skills, and helped them to perform better in learning programming by using Facebook for interaction and participation in the online discussion with a facilitator and peers.

2-Chloropyridine-3-carbonitrile derivative 1 was utilized as a key precursor to build a series of linear and angular annulated pyridines linked to a 6-hydroxy-4,7-dimethoxybenzofuran moiety. Reaction of substrate 1 with various hydrazines afforded pyrazolo[3,4-b]pyridines. Treatment of substrate 1 with 1,3-N,N-binucleophiles including 3-amino-1,2,4-triazole, 5-amino-1H-tetrazole, 3-amino-6-methyl-1,2,4-triazin-5(4H)-one and 2-aminobenzimidazole produced the novel angular pyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrimidine, pyrido[3,2-e][1,2,4]tetrazolo[1,5-a]pyrimidine, pyrido[3′,2′:5,6] pyrimido[2,1-c][1,2,4]triazine and benzo[4,5]imidazo[1,2-a]pyrido[3,2-e]pyrimidine, respectively. Reaction of substrate 1 with 1,3-C,N-binucleophiles including cyanoacetamides and 1H-benzimidazol-2-ylacetonitrile furnished 1,8-naphthyridines and benzoimidazonaphthyridine. Moreover, reacting substrate 1 with 5-aminopyrazoles gave pyrazolo[3,4-b][1,8]naphthyridines. Finally, reaction of compound 1 with 6-aminouracils as cyclic enamines yielded pyrimido[4,5-b][1,8]naphthyridines. Some of the synthesized products showed noteworthy antimicrobial efficiency against all types of microbial strains. Structures of the produced compounds were established using analytical and spectroscopic tools.

The goal of this study was directed to synthesize a novel class of annulated compounds containing difuro[3,2-c:3′,2′-g]chromene. Friedländer condensation of o-aminoacetyl derivative 3 was performed with some active methylene ketones, namely, 1,3-cyclohexanediones, pyrazolones, 1,3-thiazolidinones and barbituric acids, furnished furochromenofuroquinolines (4,5), furochromenofuropyrazolopyridines (6–8), furochromenofurothiazolopyridines (9,10) and furochromenofuropyridopyrimidines (11, 12), respectively. Also, condensation of substrate 3 with 5-amine-3-methyl-1H-pyrazole and 6-amino-1,3-dimethyluracil, as cyclic enamines, resulted in polyfused systems 13 and 14, respectively. In vitro antimicrobial efficiency of the prepared heterocycles against microbial strains exhibited variable inhibition action, where compound 3 was the most effective against all kinds of microorganisms. A significant cytotoxic activity was seen upon the annulation of the starting compound with thiazolopyridine (9 and 10) as well as pyridopyrimidine moieties (11, 12 and 14). The spectroscopic and analytical results were used to infer the structures of the novel synthesized compounds.

BACKGROUND: Many ophthalmological complications have been associated with hydrocephalus (HC), including ocular motility disorders, visual field defects, optic atrophy, and loss of visual acuity. No studies have investigated the prevalence of strabismus and visual outcomes of children with congenital HC after ventriculoperitoneal (VP) shunt in Saudi Arabia. OBJECTIVES: Estimate the frequency of strabismic children diagnosed with HC who underwent a VP shunt procedure. DESIGN: Medical record review SETTING: Tertiary care center PATIENTS AND METHODS: We reviewed the files of all pediatric patients diagnosed with hydrocephalus before the age of 2 years and treated with shunts during the period 2010 to 2020 at our institution. MAIN OUTCOME MEASURES: Strabismus types and ophthalmic assessment (visual state, outcomes, and ocular motility state). SAMPLE SIZE AND CHARACTERISTICS: 190 children; 98 (51.5%) males. RESULTS: Eighty-nine (46.8%) had congenital HC followed by intraventricular hemorrhage 36 (18.9%); 74 (38.9%) patients had regular follow-ups in ophthalmology. Sixty-five (34.2%) patients had no ophthalmic assessment or fundus examination records, while 63 (33.1%) were diagnosed with strabismus. At the initial assessment, 26 (13.6%) patients had exotropia (XT). At the final assessment, 7 (3.6%) patients had XT. The association between VP shunt and strabismus was statistically significant, (χ2=6.534, df=1, P

COX-2 plays a key role in converting arachidonic acid into prostaglandins. This makes it a significant target for treating inflammation. Selective COX-2 inhibitors have marked a new phase in inflammatory treatment, providing significant effectiveness while reducing negative side effects. Herein, we aimed at the design and synthesis of new anti-inflammatory agents 5a–f, 7a–b, 10a–f, and 13a–b with expected selective inhibition for COX-2. Compounds 5d–f, 7b, and 10c–f showed significant COX-2 inhibition with IC50 in the range of 0.06–0.09 μM, indicating powerful pharmacological potential. In light of this, eight compounds were selected for further testing in vivo to assess their selectivity toward COX-1/COX-2 enzymes with the ability to reduce paw thickness. Compounds 5f and 7b showed significant anti-inflammatory effects without causing stomach ulcers, as they showed significant in vivo inhibition for paw thickness at 63.35% and 46.51%, as well as paw weight at 68.26% and 64.84%. Additionally, the tested compounds lowered TNF-α by 61.04% and 64.88%, as well as PGE-2 by 60.58% and 57.07%, respectively. Furthermore, these potent compounds were thoroughly analyzed for their pain-relieving effects, histological changes, and toxicological properties. Assessing renal and stomach function, as well as measuring liver enzymes AST and ALT, together with kidney indicators creatinine and urea, offered valuable information on their safety profiles. Molecular modeling studies explain the complex ways in which the strong interacts with the COX-2 enzyme. This comprehensive strategy emphasizes the therapeutic potential and safety profiling of these new analogues for managing inflammation.

Breast cancer is a serious threat to the health and lives of women. Two novel series of N′-(2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazides and 1-(aryl)-3-(6-methylimidazo[2,1-b]thiazol-5-yl)ureas were designed, synthesized and investigated for their anticancer efficacy against the MCF-7 breast cell line. Three compounds of the first series showed potent activity toward MCF-7 with IC50 in the range 8.38–11.67 µM, respectively, as compared to Sorafenib (IC50 = 7.55 µM). N′-(1-butyl-2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazide inhibited VEGFR-2 with IC50 = 0.33 µM when compared with Sorafenib (IC50 = 0.09 µM). Furthermore, this compound was introduced to PCR assessment, where it increased Bax, caspase 8, caspase 9 and cytochrome C levels by 4.337-, 2.727-, 4.947- and 2.420-fold, respectively, while it decreased levels of Bcl-2, as the anti-apoptotic gene, by 0.359-fold when compared to the untreated control MCF-7. This compound was also arrested in the G2/M phase by 27.07%, compared with 11.31% for the control MCF-7. Furthermore, it induced early and late apoptosis in MCF-7. In addition, a molecular docking study in the VEGFR-2 active site was performed to assess the binding profile for the most active compounds. Moreover, ADME parameters of the targeted compounds were also evaluated.

This study focuses on reviewing information from several articles published in educational and social sciences journals worldwide to document the trend of geometric thinking studies in the Indonesian context. The current study shows that the number of publications on geometric thinking has increased in the last four years. The studies conducted in Indonesia and for Indonesian students used a systematic review guided by PRISMA to examine a hundred articles indexed by Scopus, Google Scholar, and Science and Technology Index (SINTA) between 2011 and 2021. Van Hiele’s Geometric Thinking Test, developed by Usiskin, is extensively used when examining geometric thinking levels in the intervention. In addition, descriptive analysis and a t-test are also employed. The result shows that the most common type of geometric thinking experimental research is quasi-experimental design, with the qualitative approach found to be the most used. Therefore, educators should increase the quantity of qualitative and quantitative studies from various nations about geometric thinking. Furthermore, it is also essential to examine the correlation between student performance in geometry and the teacher’s level of geometric thinking. Finally, combining the van Hiele Geometry test with interviews is strongly advised to provide comprehensive and in-depth data for examining geometric thinking.

Vilsmeier–Haack formylation of 3-aminothiazolotriazolopyridine-7,9-dicarbonitrile 3 afforded the corresponding aldehyde derivative 4 in a 65% yield. Some Schiff bases 5-7 were efficiently synthesized by reacting substrate 4 with some primary amines. Reaction of substrate 4 with some active methylene nitriles produced 2-amino-3-substituted-pyridotriazolothiazolopyridines 8–12. Substrate 4 was utilized as a key intermediate for a diversity of pyridotriazolothiazolopyrazolopyridines 13–15, through the Friedlander reaction with pyrazolidine-3,5-dione, 5-amino-2,4-dihydro-3H-pyrazol-3-one, and 5-phenyl-2,4-dihydro-3H-pyrazol-3-one. Further, the reaction of substrate 4 with 5-amino-3-methyl-1H-pyrazole and 6-aminouracil, as cyclic enamines, produced pyridotriazolothiazolopyrazolopyridine 16 and pyridotriazolothiazolopyridopyrimidine 17, respectively. The antimicrobial efficiency was assessed for the synthesized products, and some of them showed notable activity. The structures of the synthesized products were confirmed using analytical and spectroscopic data. [ABSTRACT FROM AUTHOR]

Quinolines are very important materials in organic synthesis due to their wide range of biological activities as well as representing one of the most research area in medicinal chemistry. Quinolines have many applications in design and synthesis of multiple heterocyclic compounds with a wide variety of biological significance. Quinolines fused heterocycles at face b using different synthetic methodologies as well as variable precursors and reaction conditions were the aim of the current review. [ABSTRACT FROM AUTHOR]

The present work aimed at differentiating five Amaranthus species from Saudi Arabia according to their morphology and the ability in nanoparticle formulation. Biogenic silver nanoparticles (AgNPs) were synthesized from leaf extracts of the five Amaranthus species and characterized by different techniques. Fourier-transform infrared spectroscopy (FT-IR) was used to identify the phyto-constituents of Amaranthus species. The nanoparticles (NPs) were characterized by UV-visible spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The antibacterial activity of the synthesized NPs was tested against Staphylococcus aureus, E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa using the agar well diffusion method. Spherical NPs varying in size and functional groups from the five plant species were demonstrated by TEM, DLS and FTIR analysis, respectively. Variations in NPs characteristics could be related to the phytochemical composition of each Amaranthus species since they play a significant role in the reduction process. EDX confirmed the presence of Ag in plant fabricated AgNPs. Antibacterial activity varied among the species, possibly related to the NPs characteristics. Varied characteristics for the obtained AgNPs may reflect variations in the phytochemical composition type and concentration among Amaranthus species used for their fabrication.

Mohammad Abdul Baseer,1 Nawaf Abdulaziz Almayah,2 Khalid Mirae Alqahtani,2 Marwan Ibrahim Alshaye,2 Meshari Mohammed Aldhahri2 1Department of Preventive Dentistry, College of Dentistry, Riyadh Elm University, Riyadh, Saudi Arabia; 2College of Dentistry, Riyadh Elm University, Riyadh, Saudi ArabiaCorrespondence: Mohammad Abdul BaseerDepartment of Preventive Dentistry, College of Dentistry, Riyadh Elm University, Post Box No 84891, Riyadh, 11681, Saudi ArabiaEmail ma_baseer@riyadh.edu.saPurpose: The objective of this study is to compare the orthodontic patient’s experiences with removable and fixed orthodontic appliances on daily activities, food consumption, and oral symptoms in Riyadh city, Saudi Arabia.Methods: This was a cross-sectional observational study carried out among orthodontic patients. A total of 150 adult patients, including 118 in the fixed orthodontic appliance group and 32 in the removable (Invisalign) orthodontic group, who met the inclusion criteria completed a validated and self-administered questionnaire. In addition, the study participants reported their experience in terms of daily routine, food consumption, and oral symptoms one week after appliance activation. Data were analyzed using the chi-square test and Fisher’s exact tests for the categorical variables. In addition, Mann–Whitney U, Kruskal–Wallis, and Spearman’s tests were also applied to the data.Results: The fixed orthodontic patients compared to the removable orthodontic cases showed significantly higher difficulty in sleeping (1.28± 1.10 vs 0.94± 0.88, p=0.024), sores on the tongue (0.97± 1.00 vs 0.56± 0.76, p=0.042) and cheeks (1.20± 1.11 vs 0.72± 0.81, p=0.027), and the presence of food debris under the appliance (1.53± 1.16 vs.1.00± 0.95, p=0.021). Moreover, the oral health impact score showed a significant positive correlation with the duration of the orthodontic treatment (r=0.339, p< 0.001) and pain intensity (r=0.309, p< 0.001).Conclusion: The fixed orthodontic treatment compared to removable orthodontic treatment resulted in more severe pain, sleeping difficulty, sores on the tongue and cheeks, and food impaction after one week of appliance activation.Keywords: removable appliance, orthodontic treatment, fixed appliance, Invisalign, oral impacts, oral health-related quality of life, OHRQoL

Many higher educational institutions have adopted Learning Management Systems. Blackboard, characterized as one of the technological educational systems, is one of the leading and extensive Learning Management Systems adopted by most universities. However, literature showed that a missing link appears between Blackboard adoption and Blackboard poor usage in teaching and learning. Therefore, this study aims to gauge the perceptions of students toward using Blackboard Collaborate in learning English as a Foreign Language academic writing. Online survey was conducted and distributed to 248 respondents. This study is quantitative in nature, employing Technology Acceptance Model theory to check Learning Management System acceptance at Saudi Electronic University in Saudi Arabia. The findings showed that all the constructs were relatively strong and had positive relationships; they were correlated with each other and the whole six hypotheses were supported as well. In this paper, the proposed model indicates that Attitude toward Use is the strongest predictor of Behaviour Intention. This study offers implications for further studies.

2-Chloropyridine-3-carbonitrile derivative 1 was utilized as a key precursor to build a series of linear and angular annulated pyridines linked to a 6-hydroxy-4,7-dimethoxybenzofuran moiety. Reaction of substrate 1 with various hydrazines afforded pyrazolo[3,4-b]pyridines. Treatment of substrate 1 with 1,3-N,N-binucleophiles including 3-amino-1,2,4-triazole, 5-amino-1H-tetrazole, 3-amino-6-methyl-1,2,4-triazin-5(4H)-one and 2-aminobenzimidazole produced the novel angular pyrido[3,2-e][1,2,4]triazolo[4,3-a]pyrimidine, pyrido[3,2-e][1,2,4]tetrazolo[1,5-a]pyrimidine, pyrido[3′,2′:5,6] pyrimido[2,1-c][1,2,4]triazine and benzo[4,5]imidazo[1,2-a]pyrido[3,2-e]pyrimidine, respectively. Reaction of substrate 1 with 1,3-C,N-binucleophiles including cyanoacetamides and 1H-benzimidazol-2-ylacetonitrile furnished 1,8-naphthyridines and benzoimidazonaphthyridine. Moreover, reacting substrate 1 with 5-aminopyrazoles gave pyrazolo[3,4-b][1,8]naphthyridines. Finally, reaction of compound 1 with 6-aminouracils as cyclic enamines yielded pyrimido[4,5-b][1,8]naphthyridines. Some of the synthesized products showed noteworthy antimicrobial efficiency against all types of microbial strains. Structures of the produced compounds were established using analytical and spectroscopic tools. [ABSTRACT FROM AUTHOR]

This article reports on an empirical study investigating the impact of using a reflective teaching model supported by dynamic assessment in English teaching sessions, and how it enhanced primary English language teachers' autonomy, self-assessment, and linguistic communication skills. The study employed a quasi-experimental design with pre-test and post-test measures and a control group. The participants were 40 English language teachers working at primary government schools during the 1st semester of the academic year 2023/24 in Saudi Arabia. The experimental group completed 12 sessions of teaching, guided by a reflective teaching model that incorporated dynamic assessment principles, while the control group followed the traditional teaching approach. The data collection instruments included a teacher autonomy questionnaire, a self-assessment checklist, and a linguistic communication test. This was done to determine The results revealed that the experimental group showed significant improvement in their autonomy, self-assessment and linguistic communication skills compared to the control group. The study concluded that using a reflective teaching model supported by dynamic assessment in teaching sessions can foster primary English language teachers' professional development and enhance their language teaching outcomes. [ABSTRACT FROM AUTHOR]

Background: The parental awareness and perceptions help in early recognition of problems in deciduous dentition, which will help us plan better preventive measures. Hence, the present study was conducted to evaluate the perceptions of Saudi parents residing in Riyadh towards the problems related to primary dentition of their children. Materials and Methods: A cross-sectional study was conducted on the patients attending private dental institution in Riyadh city. Information about demographic details, questions related to maintenance of primary teeth, and future implications of poor primary dentition health were collected. Descriptive statistics and Chi-square test were used for the analysis. The level of significance was set at P < 0.05. Results: A total of 1773 male and females filled up the survey form, which comprised of 28% males and 72% females, and maximum parents (68%) were university graduates. Overall better responses were in females and parents having more children. Conclusion: Over all mothers had a higher level of knowledge and positive attitude towards their children's oral health as compared to fathers. Developing and strengthening optimistic outlook among parents towards oral health especially primary dentition is utmost important.

2-Chloro-5-[(6-hydroxy-4,7-dimethoxy-1-benzofuran-5-yl)carbonyl]pyridine-3-carbonitrile (3) was synthesized and its chemical reactivity was investigated toward a diversity of binucleophiles. Treatment of compound 3 hydrazine hydrate and phenylhydrazine produced pyrazolo[3,4-b]pyridines while isoxazolo[5,4-b]pyridine was obtained from reacting compound 3 with hydroxylamine. A diversity of pyrido[2,3-d]pyrimidines was synthesized from treatment of staring substrate 3 with some 1,3-N,N-binucleophiles. Treating compound 3 with some 1,4-binucleophiles including ethylenediamine, o-phenylenediamine, 2-aminophenol and 2-aminothiophenol furnished pyrido[2,3-e][1,4]diazepine 12 and pyrido[2,3-b][1,5] benzodiazepine 13, pyrido[2,3-b][1,5]benzoxazepine 14 and pyrido[2,3-b][1,5] benzothiazepine 15, respectively. The synthesize compounds shown remarkable effect against yeast and fungus, while compounds 4 and 7–11 exhibit excellent efficacy against all types of Gram + and Gram - bacteria. Structures of the produced compounds were established using analytical and spectroscopic tools. [ABSTRACT FROM AUTHOR]

The goal of this study was directed to synthesize a novel class of annulated compounds containing difuro[3,2-c:3′,2′-g]chromene. Friedländer condensation of o-aminoacetyl derivative 3 was performed with some active methylene ketones, namely, 1,3-cyclohexanediones, pyrazolones, 1,3-thiazolidinones and barbituric acids, furnished furochromenofuroquinolines (4,5), furochromenofuropyrazolopyridines (6–8), furochromenofurothiazolopyridines (9,10) and furochromenofuropyridopyrimidines (11, 12), respectively. Also, condensation of substrate 3 with 5-amine-3-methyl-1H-pyrazole and 6-amino-1,3-dimethyluracil, as cyclic enamines, resulted in polyfused systems 13 and 14, respectively. In vitro antimicrobial efficiency of the prepared heterocycles against microbial strains exhibited variable inhibition action, where compound 3 was the most effective against all kinds of microorganisms. A significant cytotoxic activity was seen upon the annulation of the starting compound with thiazolopyridine (9 and 10) as well as pyridopyrimidine moieties (11, 12 and 14). The spectroscopic and analytical results were used to infer the structures of the novel synthesized compounds. [ABSTRACT FROM AUTHOR]

The novel chromonyltriazolo[3,4-b][1,3,4]thiadiazole derivative 5 was efficiently synthesized and utilized as key intermediate for construction of a diversity of heterocyclic rings; through reactions with binucleophilic reagents. Treating electron deficient substrate 5 with hydrazine hydrate, phenylhydrazine and hydroxylamine furnished pyrazolyl/isoxazolyltriazolo[3,4-b][1,3,4]thiadiazoles 6-8. Also, reacting substrate 5 with guanidine, cyanoguanidine and thiourea provided pyrimidinyltriazolo[3,4-b][1,3,4]thiadiazoles 9-11. Reaction of substrate 5 with ethylenediamine and o-phenylenediamine afforded diazepine derivatives 12 and 13. Reaction of substrate 5 with malononitrile, ethyl cyanoacetate and cyanoacetamide afforded pyrans 14, 15 and pyridine 16 linked triazolo[3,4-b][1,3,4]thiadiazolyl chromeno[2,3-b]pyridines. The anticancer efficiency of the current compounds presented diverse inhibitory action against certain cancer cell lines. On the basis of analytical and spectral findings, the structures of the synthesized products were confirmed. [ABSTRACT FROM AUTHOR]

The oral mucosa plays a crucial protective role as a natural barrier to exogenous substances and pathogens. Tobacco in any form, either smoked or smokeless, can cause a broad spectrum of oral mucosal alterations, ranging from harmless to more serious dysplastic and carcinomatous lesions. This study aimed to investigate the prevalence of oral mucosal lesions (OMLs) in adult patients who do and do not use tobacco, their habits, and the relative risk of developing oral lesions associated with these habits. [ABSTRACT FROM AUTHOR]

A variety of structurally different pyrimidines were synthesized. Elemental analysis, FT-IR, 1H NMR, and 13C NMR spectroscopy were used to confirm the chemical structures of all prepared compounds. The synthesized pyrimidines were screened against the growth of five human cancer cell lines (prostate carcinoma PC3, liver carcinoma HepG-2, human colon cancer HCT-116, human breast cancer MCF-7, human lung cancer A-549), and normal human lung fibroblasts (MRC-5) using MTT assay. Most of the screened pyrimidines have anti-proliferative activity on the growth of the PC3 cell line. Compounds 3b and 3d were more potent than the reference vinblastine sulfate (~2 to 3 × fold) and they can be considered promising leads for treating prostate cancer disease. Moreover, the screened compounds 3b, 3f, 3g, 3h, and 5 were assessed according to the values of their selectivity index (SI) and were found to be more selective and safer than vinblastine sulfate. Furthermore, using in silico computational tools, the physicochemical properties of all pyrimidine ligands were assessed, and the synthesized compounds fall within the criteria of RO5, thus having the potential to be orally bioavailable.

A new N,N′-disubstituted piperazine conjugated with 1,3,4-thiadiazole and 1,2,4-triazole was prepared and the chemical structures were identified by IR, NMR and elemental analysis. All the prepared compounds were tested for their antimicrobial activity. The antimicrobial results indicated that the tested compounds showed significant antibacterial activity against gram-negative strains, especially E. coli, relative to gram-positive bacteria. Docking analysis was performed to support the biological results; binding modes with the active site of enoyl reductase amino acids from E. coli showed very good scores, ranging from −6.1090 to −9.6184 kcal/mol. Correlation analysis was performed for the inhibition zone (nm) and the docking score.

COX-2 plays a key role in converting arachidonic acid into prostaglandins. This makes it a significant target for treating inflammation. Selective COX-2 inhibitors have marked a new phase in inflammatory treatment, providing significant effectiveness while reducing negative side effects. Herein, we aimed at the design and synthesis of new anti-inflammatory agents 5a–f, 7a–b, 10a–f, and 13a–b with expected selective inhibition for COX-2. Compounds 5d–f, 7b, and 10c–f showed significant COX-2 inhibition with IC50 in the range of 0.06–0.09 μM, indicating powerful pharmacological potential. In light of this, eight compounds were selected for further testing in vivo to assess their selectivity toward COX-1/COX-2 enzymes with the ability to reduce paw thickness. Compounds 5f and 7b showed significant anti-inflammatory effects without causing stomach ulcers, as they showed significant in vivo inhibition for paw thickness at 63.35% and 46.51%, as well as paw weight at 68.26% and 64.84%. Additionally, the tested compounds lowered TNF-α by 61.04% and 64.88%, as well as PGE-2 by 60.58% and 57.07%, respectively. Furthermore, these potent compounds were thoroughly analyzed for their pain-relieving effects, histological changes, and toxicological properties. Assessing renal and stomach function, as well as measuring liver enzymes AST and ALT, together with kidney indicators creatinine and urea, offered valuable information on their safety profiles. Molecular modeling studies explain the complex ways in which the strong interacts with the COX-2 enzyme. This comprehensive strategy emphasizes the therapeutic potential and safety profiling of these new analogues for managing inflammation. [ABSTRACT FROM AUTHOR]

Breast cancer is a serious threat to the health and lives of women. Two novel series of N′-(2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazides and 1-(aryl)-3-(6-methylimidazo[2,1-b]thiazol-5-yl)ureas were designed, synthesized and investigated for their anticancer efficacy against the MCF-7 breast cell line. Three compounds of the first series showed potent activity toward MCF-7 with IC50 in the range 8.38–11.67 µM, respectively, as compared to Sorafenib (IC50 = 7.55 µM). N′-(1-butyl-2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazide inhibited VEGFR-2 with IC50 = 0.33 µM when compared with Sorafenib (IC50 = 0.09 µM). Furthermore, this compound was introduced to PCR assessment, where it increased Bax, caspase 8, caspase 9 and cytochrome C levels by 4.337-, 2.727-, 4.947- and 2.420-fold, respectively, while it decreased levels of Bcl-2, as the anti-apoptotic gene, by 0.359-fold when compared to the untreated control MCF-7. This compound was also arrested in the G2/M phase by 27.07%, compared with 11.31% for the control MCF-7. Furthermore, it induced early and late apoptosis in MCF-7. In addition, a molecular docking study in the VEGFR-2 active site was performed to assess the binding profile for the most active compounds. Moreover, ADME parameters of the targeted compounds were also evaluated. [ABSTRACT FROM AUTHOR]

The present work aimed at differentiating five Amaranthus species from Saudi Arabia according to their morphology and the ability in nanoparticle formulation. Biogenic silver nanoparticles (AgNPs) were synthesized from leaf extracts of the five Amaranthus species and characterized by different techniques. Fourier-transform infrared spectroscopy (FT-IR) was used to identify the phyto-constituents of Amaranthus species. The nanoparticles (NPs) were characterized by UV-visible spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The antibacterial activity of the synthesized NPs was tested against Staphylococcus aureus, E. coli, Klebsiella pneumoniae and Pseudomonas aeruginosa using the agar well diffusion method. Spherical NPs varying in size and functional groups from the five plant species were demonstrated by TEM, DLS and FTIR analysis, respectively. Variations in NPs characteristics could be related to the phytochemical composition of each Amaranthus species since they play a significant role in the reduction process. EDX confirmed the presence of Ag in plant fabricated AgNPs. Antibacterial activity varied among the species, possibly related to the NPs characteristics. Varied characteristics for the obtained AgNPs may reflect variations in the phytochemical composition type and concentration among Amaranthus species used for their fabrication. [ABSTRACT FROM AUTHOR]

The essential aim of the present study is designed to utilize 4,9-dimethoxy-5-oxo-5H-furo[3,2-g]chromene-6-carbonitrile (1) to build some novel heterocyclic systems containing benzofurans as well as furo[3,2-g]chromenes. Ring opening ring closure reactions of compound 1 with N-phenyl-2-cyanoacetamide produced 8-amino-furochromenopyridine-7-carboxamide 2, which cyclized with some electrophilic reagents giving furochromenopyridopyrimidines (63–73% yields). The reaction of carbonitrile 1 with pyrazolone derivatives yielded furochromenopyrazolopyridines 10 and 11 in good yields. Also, benzo[h]furochromeno naphthyridine 13 was synthesized from recyclization of carbonitrile 1 with 1-ethyl-4-hydroxyquinolin-2(1H)-one (12). On a different mechanism, recyclization of carbonitrile 1 with some 1,3-binucleophiles afforded pyrido[2,3-d]pyrimidines (14 and 15), pyrimido[1,2-a]pyrimidine 17 and pyrimido[2,1-c][1,2,4]triazine 19 in suitable yields (62–71%). Finally, the reaction of carbonitrile 1 with 1,3-cyclohexanedione and 1,4-cyclohexanedione in 2:1 molar ratio yielded polyfused systems 20 and 21, respectively. Based on spectral and analytical results, the structures of the all products were inferred. [ABSTRACT FROM AUTHOR]

The fabrication of a clinically acceptable dental prosthesis requires proper communication between the dentist and the dental technician. Prosthodontic educators have been concerned with this interaction and communication. Fixed prosthodontics laboratories revealed that the technicians are often dissatisfied with the information provided in work authorizations. Objective: To evaluate the quality of communication between dentists and laboratory technicians via work authorizations for fixed prosthodontics in both governmental and private dental laboratories in Riyadh area from the technician’s perspective. Methods: A sample of 66 dental laboratories, including all government dental laboratories and a selected number of randomly chosen private dental laboratories from each district of Riyadh (40%), participated in the survey.A questionnaire was developed to include questions related to the following areas of work authorization: clarity and accuracy of instructions, patient information, type of prosthesis, choice of materials, design and shade of the prosthesis and type of porcelain glaze. The questionnaire was answered in a face-to-face interview by technicians who were qualified in fixed prosthetic work. Data were analyzed through parametric tests (T-test and one-way ANOVA) to identify significant values (P

The chemical reactivity of 2-methylchromone-3-carbonitrile (1) was investigated toward a diversity of active methylene nucleophiles. Ring-opening followed by recyclization reactions of compound 1 with some active methylene nitriles afforded 2-amino-3-substituted-4-methylchromeno[2,3-b]pyridin-5-ones. Also, reactions of carbonitrile 1 with some active methylene ketones produced 2,4-dimethylchromeno [2,3-b]pyridin-5-ones. Annulated chromeno[2,3-b]pyrazolo[4,3-e]pyridine, chromeno[2,3-b][1,3]thiazolo[5,4-e]pyridine and chromeno[2,3-b]quinoline were efficiently synthesized from reaction of carbonitrile 1 with some cyclic methylene compounds. Heteroannulated chromeno[3′,2′:5,6]pyrido[2,3-d]pyrimidines and chromeno[2,3-b][1,8]naphthyridines were synthesized from reaction of compound 2 with formic acid, formamide, and malononitrile, cyanoacetamide, respectively. Chromeno[2′,3′:6,5]pyrido[2,3-b][1,8]naphthyridine 17 was synthesized from reaction of compound 2 with malononitrile dimer. Structures of the newly synthesized products were deduced based on their analytical and spectral data. [ABSTRACT FROM AUTHOR]

The present work is directed to synthesize and evaluate the antimicrobial activity of some novel 2-heteroarylchromeno[2,3-d]pyrimidines. 2-(6,8-Dimethylchromon-3-yl)-8-methoxy-4H-chromeno[2,3-d]pyrimidine-4,5(3H)-dione (4) was successfully synthesized and utilized as a building block to produce a variety of heterocyclic compounds. 2-(4-Pyrazolyl/isoxazolyl)chromeno[2,3-d]pyrimidines 5–7 were obtained from the reaction of compound 4 with hydrazine hydrate, phenylhydrazine, and hydroxylamine, respectively. Also, 2-(6-pyrimidinyl)chromeno[2,3-d]pyrimidines 8–12 were efficiently prepared from reacting compound 4 with guanidine, cyanoguanidine, thiourea, acetamidine, and benzamidine, respectively. Further, chromeno[2,3-d]pyrimidines linked diazepine 13, benzodiazepine 14, benzoxazepine 15 and benzothiazepine 16 were also synthesized. The synthesized compounds were examined for their antimicrobial efficiency. Pyrazolylchromeno[2,3-d]pyrimidines 5 and 6 showed the best activity against all kinds of microorganisms. Structures of the synthesized compounds were validated using analytical and spectral data. [ABSTRACT FROM AUTHOR]

Friedländer reaction of 4-aminocoumarin-3-carboxaldehyde (1) with thiobarbituric acid provided 2-thioxochromenopyridopyrimidine 2 which employed as a synthetic intermediate to create a novel annulated chromenopyridothiazolopyrimidines. Treatment of compound 2 with a diversity of nucleophiles including; dibromoethane, oxalyl chloride, phenacyl bromide, chloroacetic acid, 3-chloropentanedione, ethyl 2-chloro-3-oxobutanoate, chloroacetonitrile and bromomalononitrile afforded chromenopyridothiazolopyrimidines 3–10, respectively. Acidic hydrolysis of carbonitrile 10 afforded the corresponding carboxamide derivative 11. Compound 11 reacted with some mono-electrophilic reagents namely acetyl chloride, benzoyl chloride, chloroacetyl chloride, triethyl orthoformate, diethyl carbonate, and carbon disulfide producing the first known chromeno[3′,4′:5,6]pyrido[2,3-d]pyrimido [4',5':4,5][1,3]thiazolo[3,2-a]pyrimidines 12–17. The antimicrobial and anticancer activities were estimated for the synthesized products and some of them appeared notable activities. The structural elucidation of the newly synthesized products was determined using analytical and spectroscopic data. [ABSTRACT FROM AUTHOR]

A variety of structurally different pyrimidines were synthesized. Elemental analysis, FT-IR, 1H NMR, and 13C NMR spectroscopy were used to confirm the chemical structures of all prepared compounds. The synthesized pyrimidines were screened against the growth of five human cancer cell lines (prostate carcinoma PC3, liver carcinoma HepG-2, human colon cancer HCT-116, human breast cancer MCF-7, human lung cancer A-549), and normal human lung fibroblasts (MRC-5) using MTT assay. Most of the screened pyrimidines have anti-proliferative activity on the growth of the PC3 cell line. Compounds 3b and 3d were more potent than the reference vinblastine sulfate (~2 to 3 × fold) and they can be considered promising leads for treating prostate cancer disease. Moreover, the screened compounds 3b, 3f, 3g, 3h, and 5 were assessed according to the values of their selectivity index (SI) and were found to be more selective and safer than vinblastine sulfate. Furthermore, using in silico computational tools, the physicochemical properties of all pyrimidine ligands were assessed, and the synthesized compounds fall within the criteria of RO5, thus having the potential to be orally bioavailable. [ABSTRACT FROM AUTHOR]