Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 5 de 5
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
J Am Chem Soc ; 145(28): 15435-15442, 2023 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-37421307

RESUMO

Metal-organic frameworks (MOFs) have emerged as excellent platforms possessing tunable and controllable optical behaviors that are essential in high-speed and multichannel data transmission in optical wireless communications (OWCs). Here, we demonstrate a novel approach to achieving a tunable wide modulation bandwidth and high net data rate by engineering a combination of organic linkers and metal clusters in MOFs. More specifically, two organic linkers of different emission colors, but equal molecular length and connectivity, are successfully coordinated by zirconium and hafnium oxy-hydroxy clusters to form the desired MOF structures. The precise change in the interactions between these different organic linkers and metal clusters enables control over fluorescence efficiency and excited state lifetime, leading to a tunable modulation bandwidth from 62.1 to 150.0 MHz and a net data rate from 303 to 363 Mb/s. The fabricated color converter MOFs display outstanding performance that competes, and in some instances surpasses, those of conventional materials commonly used in light converter devices. Moreover, these MOFs show high practicality in color-pure wavelength-division multiplexing (WDM), which significantly improved the data transmission link capacity and security by the contemporary combining of two different data signals in the same path. This work highlights the potential of engineered MOFs as a game-changer in OWCs, with significant implications for future high-speed and secure data transmission.

2.
J Am Chem Soc ; 141(51): 20037-20042, 2019 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-31825615

RESUMO

Synthesis of nanoscale metal-organic frameworks (MOFs) is a highly challenging task because conventional soluble metal salt precursors are not easy to manipulate spatially, thus normally leading to bulk MOFs. In the present work, V2CTx MXene is demonstrated for the first time as a metal precursor to fabricate two-dimensional (2D) MOF nanosheets, whose thickness (6 to 18 nm) can be tuned by varying the reaction temperature. The highly electronegative surface atoms of MXene and sufficient accessible attacking sites for ligands are responsible for the evolution of 2D MOF nanosheets. Moreover, highly oriented and smooth MOF thin films have been grown based on these nanosheets using a convenient spin coating process. With the impregnation of nonvolatile H3PO4, the MOF thin film exhibits a proton-conducting property. This study demonstrates that high-quality 2D MOF sheets and thin films are enabled by 2D MXene precursors. We believe that the high-quality MOF films prepared in this study pave the way for many device applications.

3.
J Pharm Bioallied Sci ; 15(Suppl 1): S508-S512, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37654413

RESUMO

Background: Salivary biomarkers can be used to diagnose illnesses, track their course, and gauge a patient's response to therapy. Inflammatory circumstances result in higher sCD44 levels. The most typical inflammatory disorder connected to periodontal tissue is called periodontitis. Therefore, the purpose "of the current study was to compare the levels of sCD44 in patients with chronic periodontitis before and after scaling and root planing. Objectives: 1) Determining CD44 concentrations in healthy individuals' spit. 2) To quantify CD44 levels in the saliva of individuals with persistent periodontitis. The third objective is to compare the levels of CD44 that can be dissolved in saliva between those with healthy gums and those with active periodontitis. 4) Assessing CD44 levels in saliva after "scaling and root planing in patients with chronic periodontitis." Materials and Methods: Half of the study participants were classified as having chronic periodontitis, while the other half had healthy gums. Participants with healthy gums and those with chronic periodontitis had their plaque levels, gingival status, and testing depths measured. All the same, data were calculated in persons with chronic periodontitis one month after they had "scaling and root planing done. Clinical attachment levels were evaluated before scaling and root planing was performed on patients with chronic periodontitis and again one month afterwards. Patients with chronic periodontitis," those whose condition had not improved following scaling and root planing (SRP), and healthy individuals all had spit tests conducted after a month. The concentration of sCD44 in the saliva was determined with a chemically coupled immunosorbent assay. Results: Salivary sCD44 levels were substantially greater in people with chronic periodontitis than in people without the condition. After one month of scaling and root planing in patients with chronic periodontitis, sCD44 levels drastically dropped (p < 0.0001). Conclusion: Chronic periodontitis is linked to elevated levels of salivary sCD44. sCD44 can be employed as a possible salivary biomarker for chronic Periodontitis.

4.
Clin Cosmet Investig Dent ; 15: 225-236, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37881242

RESUMO

Background: Physicians are more likely to examine children than dentists; thus, they may have a significant role in detecting oral and dentofacial problems. This study aimed to determine the rate and comprehensiveness of examinations, the rate and quality of referral practices, and the predictors of referral practice of physicians regarding orthodontic problems among children. Methods: In a multi-center cross-sectional study, a total of 518 physicians in Saudi Arabia were subjected to an e-questionnaire of four sections: (1) Physicians' demographic and work-related characteristics; (2) Physicians' comprehensiveness of oral and orthodontic examinations; (3) Physicians' referral practices to orthodontists and reasons considered for referral; and (4) Physicians' sources of orthodontic education. Logistic regression analysis was applied to identify the significant predictors of referral practice. The significance was set at p < 0.05. Results: Most physicians reported partial oral (78.5%) and orthodontic (72.2%) examinations, while the full examination was reported by only 12% and 2.5% of physicians, respectively. Referral to orthodontists was practiced by most of the physicians (83.8%), yet for the majority of them, the quality of referral was poor (40.3%) or fair (46.1%), with only 13.6% who practiced quality referral. Dental development issues (53.3%) and functional issues (51.5%) were reported as the main reasons for referral, followed by family/patient request (42.9%), dental alignment (42.5%), oral respiratory issues (32.4%), and finally jaw relation (26.1%). Referral practice was predicted by the comprehensive oral (OR = 2.37, p = 0.007) and orthodontic (OR = 4.26, p < 0.001) examinations, number of patients seen by the physician (OR = 1.58, p = 0.007), and level of training (OR = 1.88, p = 0.03). Conclusion: Although most physicians reported high rates of examination and referral practices on orthodontic problems among children in Saudi Arabia, only a small portion showed comprehensive examinations and quality referral practice. Including dental courses in medical curricula and improving oral and orthodontic examination guidelines for physicians are recommended.

5.
J Infect Public Health ; 15(11): 1169-1174, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36215800

RESUMO

INTRODUCTION: The third (Omicron) wave had caused significant increase in the number of COVID-19 cases around the globe. The severity of the disease dependeds on the extent of the vaccination status. METHODS: This is a retrospective study of infected COVID-19 patients during the third (Omicron) wave in a hospital in Saudi Arabia. RESULTS: A total of 400 patients were included with 220 (55 %) males and 180 (45 %) females, and a mean age (+/- SD) of 36.34 + 16.47 years. The most common presenting symptoms were: sore throat 159 (39.8 %), cough 158 (39.5 %), fever 132 (33 %), headache 122 (30.5 %), and muscle ache 124 (31%). There was no difference in underlying conditions, signs and symptoms between males and females apart from the occurrence of sore throat with an OR of 2.014 (95 % CI: 1.103-3.677, P = 0.023) and need of hospitalization OR 2.457 (95 % CI: 1.168-5.167, P value =.018) in a binary logistic regression comparison. The need for hospitalization was inversely related to the number of COVID-19 vaccination doses. The rate of admission was 8 (72.7 %), 34 (12 %), 4 (5.4 %) for one, two, and three doses of COVID-19 vaccine, respectively (P < 0.0001). Of all the patients, 14 (3.5 %) and 8 (2 %) required intensive care (ICU) admission and mechanical ventilation, respectively. The median Ct-value of SARS-CoV-2 was higher in those who had 2 or 3 doses compared to those who had one dose of the COVID-19 vaccine, but the difference did not reach statistical significance. None of the included patients died during the study period. CONCLUSION: Omicron variant symptoms among infected patients are generally milder compared to other variants. Prior COVID-19 vaccination may limit disease severity and need for hospitalization.


Assuntos
COVID-19 , Faringite , Feminino , Masculino , Humanos , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Vacinas contra COVID-19 , SARS-CoV-2 , COVID-19/prevenção & controle , Estudos Retrospectivos , Arábia Saudita/epidemiologia , Dor
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA