Assembling molecular machines into crystals provides a way to harness their power on large length scales, but the development of a crystal analogue to a molecular motor remains a challenge. The molecule ()-5-(anthracen-9-ylmethylene)-3-butylthiazolidine-2,4-dione () has and isomers with strongly overlapping absorption spectra. This spectroscopic property allows both → and → photoisomerization reactions to be driven by a single light source, and simulations indicate this property can provide a route to robust oscillatory motion.
View Article and Find Full Text PDFBackground: This study aimed to determine the rate of telemedicine (TM) use and the levels of awareness, knowledge, attitude, and skills of TM among primary healthcare (PHC) providers.
Methods: In a cross-sectional study, 104 PHC providers were subjected to a validated AKAS scale via Survey Monkey. The tool consists of 4 parameters that users can respond to using a 4-point Likert scale to assess their awareness (12 statements), knowledge (11 statements), attitude (11 statements), and skills (13 statements) on TM.
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.
Background: Occupational and physical therapists are at risk of musculoskeletal pain and injuries possibly due to their work-related activities, posture and affected body mechanics.
Aims: To investigate the epidemiology of lower back pain among rehabilitation professionals.
Methods: A cross-sectional survey of 259 physical and occupational therapists in rehabilitation centres in Saudi Arabia was conducted during July-August 2019, using the Modified Nordic Questionnaire.
Angew Chem Int Ed Engl
February 2021
The ability to exhibit life-like oscillatory motion fueled by light represents a new capability for stimuli-responsive materials. Although this capability has been demonstrated in soft materials like polymers, it has never been observed in molecular crystals, which are not generally regarded as dynamic objects. In this work, it is shown that molecular crystalline microwires composed of (Z)-2-(3-(anthracen-9-yl)allylidene)malononitrile ((Z)-DVAM) can be continuously actuated when exposed to a combination of ultraviolet and visible light.
View Article and Find Full Text PDFBackground: In Saudi Arabia, healthcare industry is undergoing major expansions to meet the demand of rapidly growing healthcare needs. The aims of this study were; (1) to assess the pattern of smartphone use in healthcare facilities, and (2) to determine perception towards its use among healthcare workers.
Method: A cross-sectional survey of 351 healthcare workers (HCWs) at King Abdulaziz Medical City (KAMC) in Riyadh, Saudi Arabia was conducted, from October to November 2016, using a previously validated perception domain to measure perception towards usefulness (5 statements) and practicality (5 statements) of smartphones in clinical settings.
The 'Therapeutics discovery: From bench to first in-human trials' conference, held at the King Abdullah International Medical Research Center (KAIMRC), Ministry of National Guard Health Affairs (MNGHA), Kingdom of Saudi Arabia (KSA) from October 10-12, 2017, provided a unique opportunity for experts worldwide to discuss advances in drug discovery and development, focusing on phase I clinical trials. It was the first event of its kind to be hosted at the new research center, which was constructed to boost drug discovery and development in the KSA in collaboration with institutions, such as the Academic Drug Discovery Consortium in the United States of America (USA), Structural Genomics Consortium of the University of Oxford in the United Kingdom (UK), and Institute of Materia Medica of the Chinese Academy of Medical Sciences in China. The program was divided into two parts.
View Article and Find Full Text PDFIonic self-complementary peptides are considered an important class of self-assembling peptides. In particular, RADARADARADARADA (RADA4) is well-known to form a relatively regular nanofiber structure that has been primarily studied in terms of its physicochemical properties, as related to its biomedical applications. However, the molecular level interactions that are involved in promoting the self-assembly of this peptide into nanofibers have not been fully elucidated.
View Article and Find Full Text PDFMatrix metalloproteinase-2 (MMP-2) is an endopeptidase that has been shown to be present in high concentrations during most tissue remodeling events, including disease states like active tumor sites, thus making it an attractive molecule for use in effecting local delivery of therapeutic molecules. Moreover, the use of non-toxic and biodegradable nanoparticles for controlled drug delivery is highly sought after. To this end, bovine serum albumin (BSA) nanoparticles (NPs) were stabilized with coatings formed using domains of varying sensitivity to MMP-2, viz.
View Article and Find Full Text PDFThe adhesion of Staphylococcus epidermidis, Escherichia coli, and Candida albicans on mucin coatings was evaluated to explore the feasibility of using the coating to increase the infection resistance of biomaterials. Coatings of bovine submaxillary mucin (BSM) were deposited on a base layer consisting of a poly(acrylic acid-b-methyl methacrylate) (PAA-b-PMMA) diblock copolymer. This bi-layer system exploits the mucoadhesive interactions of the PAA block to aid the adhesion of mucin to the substratum, whereas the PMMA block prevents dissolution of the coating in aqueous environments.
View Article and Find Full Text PDFBoth visible and infrared (IR) spectroscopic ellipsometry have been employed to study the structure of thin layers of bovine submaxillary mucin (BSM) adsorbed on poly(acrylic acid-block-methyl methacrylate) (PAA-b-PMMA) copolymer and poly(methyl methacrylate) (PMMA) surfaces at three pH values (3, 7, and 10). The adsorbed mucin layer on the copolymer surface had the greatest thickness (17 nm) when adsorbed from a mucin solution at a pH of 3. For the first time, IR ellipsometry was used to identify adhesive interactions and conformational changes in mucin/polymer double layers.
View Article and Find Full Text PDFThe addition of cetylpyridinium chloride (CPC) to aqueous dispersions of poly(N-isopropylacrylamide) [poly(NIPAM)] and poly(N-isopropylacrylamide-co-acrylic acid) [poly(NIPAM-co-AAc)] microgel particles leads to absorption of the CPC into the particles and to corresponding changes in their hydrodynamic diameter. With the latter set of particles there is a strong pH dependence. The dependence of both hydrodynamic diameter and electrophoretic mobility of the microgel particles on the added CPC concentration show a strong correlation with CPC uptake, as obtained from direct CPC absorption measurements.
View Article and Find Full Text PDFThe formation and characterization of close-packed monolayers of negative, poly(N-isopropylacrylamide)-based microgel particles onto positively charged silicon wafers is described. The silicon wafers were rendered positive by first oxidizing their surface to silica and then adsorbing a layer of poly(ethyleneimine). The thickness of the deposited microgel monolayers (under aqueous conditions) has been determined by spectroscopic ellipsometry as a function of temperature (20-60 degrees C), pH (3-8), and added NaCl concentration (0-1 M).
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