Solar-Powered Molecular Crystal Motor Based on an Anthracene-Thiazolidinedione Photoisomerization Reaction.

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 (Z)-5-(anthracen-9-ylmethylene)-3-butylthiazolidine-2,4-dione (C4-ATD) has E and Z isomers with strongly overlapping absorption spectra. This spectroscopic property allows both Z → E and E → Z photoisomerization reactions to be driven by a single light source, and simulations indicate this property can provide a route to robust oscillatory motion. Reprecipitation in an aqueous surfactant enables the growth of single crystal microwires that exhibit continuous mechanical oscillations under a wide range of illumination conditions, including ambient solar irradiation. Molecular crystal motors provide a new approach for transforming continuous light into oscillatory mechanical motion.

Light-Powered Autonomous Flagella-Like Motion of Molecular Crystal Microwires.

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. The photo-induced motion mimics the oscillatory behavior of biological flagella and enables propagation of microwires across a surface and through liquids, with translational speeds up to 7 µm s-1 . This is the first example of molecular crystals that show complex oscillatory behavior under continuous irradiation. A model that relates the rotation of the transition dipole moment between reversible E→Z photoisomerization to the microscopic torque can qualitatively reproduce how the rotational frequency depends on light intensity and polarization.

Use of smartphone and perception towards the usefulness and practicality of its medical applications among healthcare workers in Saudi Arabia.

BACKGROUND: 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. Pattern of use of smartphones and health-related applications in healthcare facilities was also investigated. Logestic regression models were applied to identify the predictors of smartphone use and installation of health-related applications for use in healthcare facilities. Significance was considered at p-value of < 0.05. RESULTS: Utilization rate of smartphone was 42.3%, and only 6.1% of all healthcare providers reported always using applications in their practice. Reasons for use were: as a source of drug information (69.8%), for disease diagnosis (56.4%), to access medical websites (42.5%), to review guidelines and protocols related to healthcare (34.1%), for procedure documentation (23.5%), and as a source of patients education materials (22.3%). Perceptions of HCWs towards smartphone use was less than satisfactory (Overall percentage mean score = 60.4 ± 18.7), with only 11.6% reporting positive perception. After adjusting for possible confounders, the total perception mean score was a significant predictor of both smartphone use (ß = 0.033, p < 0.001) and medical applications installation (ß = 0.033, p < 0.001). Installation of medical applications was also predicted by being a physician (ß = 0.008, p = 0.024). CONCLUSION: Smartphone utilization in healthcare facilities by HCWs in Saudi Arabia is low. This could be attributed to their less than satisfactory level of perception towards its use. Smartphone use and installation of medical applications for use in health facilities were predicted by perceived usefulness and practicality of its use. Intervention from higher health authorities is necessary to enforce the importance of smartphone use in clinical practice. Conduction of further studies on the impact of smart phone use on the healthcare quality in Saudi Arabia is recommended.

Moringa oleifera Gum-Assisted Synthesis and Characterization of CoAgxFe2-xO4: Insight into Structural, Magnetic, Optical, and Biomedical Properties.

The sol-gel method was employed to prepare nano CoFe2O4 and silver-substituted CoFe2O4 nanohybrids (CoAgxFe2-xO4, x = 0, 0.1, 0.2, 0.3, 0.4) utilizing Moringa oleifera gum as biofuel. The morphology, size, shape, magnetic, optical, and functional groups of the crystallites were determined using various techniques such as UV-visible, Fourier transform infrared, X-ray diffraction, Rietveld, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, and photoluminescence. The produced nanoferrite has a spherical shape with cubic spinal structures. The optical properties were investigated in two different bands in the photoluminescence emission spectra at 469 and 493 nm. Saturation magnetization (Ms) and coercivity (Hc) decrease as the Ag content increases significantly. Furthermore, antibacterial (Gram-positive bacteria bacterial strains, Bacillus subtilis and Staphylococcus aureus, and Gram-negative bacterial strains, Pseudomonas aeruginosa, and Escherichia coli), antibiofilm activity (E. coli), and antioxidant (DPPH) activities were investigated. The substantial increase in the silver content offers a constructive impact on studied biomedical activities. These findings encourage additional research into the use of hybrid nanoparticles (an amalgamation of ferrite and a noble metal) in biomedical and pharmaceutical applications.

Awareness, Knowledge, Attitude, and Skills (AKAS) of Telemedicine and Its Use by Primary Healthcare Providers.

Background: 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. Total and percentage mean scores (PMS) were calculated for each parameter. Participants were categorized in each parameter into three categories: low (≤ 49% score), average (50-70% score), and high (≥ 71% score) levels. The association of AKAS levels with personal characteristics and TM use was investigated. The significance was set at p<0.05. Results: One-half of participants (51%) reported current use of TM, and two-thirds (63.5%) reported a high level of AKAS, with a PMS of 72.9±14.7, 95% CI: 70.1-75.7. There were significant associations between the following: years of experience and levels of knowledge (Χ2LT = 6.77, p= 0.009) and skills (Χ2LT = 4.85, p = 0.028), respectively; and total household income and levels of skills (Χ2LT = 6.91, p= 0.009). The rate of TM use was significantly associated with awareness levels (Χ2LT = 6.14, p = 0.013). Lack of training ranked as the first barrier (45.5%), followed by connection problems and tools' unavailability (35.1% each). The participants recommended providing TM training (41.1%) and stabilization of connection and networking signals (30.1%). Conclusion: Despite their high level of TM awareness, the rate of TM use by PHC providers is less than satisfactory. Establishing standardized TM training and supporting the network signals are recommended. A large-scale study on the impact of TM integration with PHC services is necessary.

Toward a mechanistic understanding of ionic self-complementary peptide self-assembly: role of water molecules and ions.

Ionic 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. Herein, a thermodynamic analysis of the influences of peptide chemistry upon self-assembly is discussed for RADA4, RADA4-K5, and RADA4-S5. The regular nanofiber structure of the assembled peptides makes it a good candidate for isothermal titration calorimetry (ITC) studies for determining the propensity for self-assembly, the critical assembly concentration (CAC), and the role hydration and ion content play in the assembly of these peptides. First, solutions containing only RADA4-K5 did not self-assemble; illustrating even slight alterations in the asymmetric terminal amino acid chemistry affects assembly. The CAC of the remaining self-assembling peptides was between ~0.1 and ~0.15 mM. Interestingly, we found that self-assembly was entropically driven with hydrophobic forces being the main driving force for RADA4 and hydrogen bonding for RADA4-S5. The role of water molecules and counterions in self-assembly was also highlighted: assembly of RADA4 led to desolvation of interfacial surfaces, whereas the net number of water molecules in the assembled complex increased upon RADA4-S5 self-assembly. Moreover, it was found that counterions did not seem to contribute significantly to self-assembly: a result in contrast to current concepts regarding the role of electrostatic interactions in self-assembly of RADA4-like peptides. A molecular level understanding of peptide self-assembly will allow for further engineering of peptides for a vast array of biomedical applications.

Physicians' Examination and Referral Practices on Orthodontic Problems Among 6-12-Year-Old Children in Saudi Arabia.

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.

Epidemiology of work-related lower back pain among rehabilitation professionals in Saudi Arabia.

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. Data on different measures of lower back pain, and its consequences and risk factors were collected. Logistic regression analysis was done to identify significant predictors of lower back pain. RESULTS: Rehabilitation professionals experienced 73.7% 1-year lower back pain prevalence, 52.5% intense pain that lasted ≥ 1 day, 22.4% chronic lower back pain, 23.9% sick-leave-seeking lower back pain and 18.5% medical-care-seeking lower back pain. Difficult/impossible activities of daily living in standing up (45.5%), employment (44.0%), climbing stairs (33.9%), walking (33.0%), sitting (29.3%), sleeping and travel (29.8% each), awakening (23.0%), social life (26.2%), and personal care (15.7%) were reported. Lower back pain was responsible for stopping work in 32.5% of participants, with a mean 1.38 (±2.96) days off work during the last year. One half of participants (50.3%) were treated by physiotherapy, 25.1% by medical care, and 39.3% requested rest days and/or sick leave. Physical stress and < 10 years' experience were significant predictors of lower back pain. CONCLUSION: Prevalence of lower back pain was high among rehabilitation professionals, with a high impact on activities of daily living. Physiotherapy was the main management adopted. Educational programmes are necessary to teach proper use of body mechanics, and sports activity programmes to reduce the risk of lower back pain and arrange for proper rest periods.

Adhesion of microorganisms to bovine submaxillary mucin coatings: effect of coating deposition conditions.

The 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. The thickness of the mucin coating was adjusted by varying the pH of the solution from which it was deposited. Thin mucin coatings decreased the numbers of bacteria but increased the numbers of C. albicans adhering to the copolymer and control surfaces. Increasing the mucin film thickness resulted in a further lowering of the density of adhering S. epidermidis cells, but it did not affect the density of E. coli. In contrast, the density of C. albicans increased with an increase in mucin thickness.

Therapeutics discovery: From bench to first in-human trials.

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. A pre-symposium day took place on October 10, during which courses were conducted on clinical trials, preclinical drug discovery, molecular biology and nanofiber research. The attendees had the opportunity for one-to-one meetings with international experts to exchange information and foster collaborations. In the second part of the conference, which took place on October 11 and 12, the clinical trials pipeline, design and recruitment of volunteers, and economic impact of clinical trials were discussed. The Saudi Food and Drug Administration presented the regulations governing clinical trials in the KSA. The process of preclinical drug discovery from small molecules, cellular and immunologic therapies, and approaches to identifying new targets were also presented. The recommendation of the conference was that researchers in the KSA must invest more fund, talents and infrastructure to lead the region in phase I clinical trials and preclinical drug discovery. Diseases affecting the local population, such as Middle East Respiratory Syndrome and resistant bacterial infections, represent the optimal starting point.

Engineered peptides with enzymatically cleavable domains for controlling the release of model protein drug from "soft" nanoparticles.

Matrix 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. K6GPQG/IASQK6 and K6HPVG/LLARK6, lysine residues being used to facilitate peptide immobilization to the BSA NPs via electrostatic interactions, and peptide domains that have a high (HPVG/LLAR) and low (GPQG/IASQ) MMP-2 cleavage rate. The MMP-2-induced cleavage rates of these two domains (the position of action being noted with a "/") have differing kinetics that can be used to provide a novel mechanism for facilitating the controlled release of molecules where local concentrations of MMP-2 are high. It was found that both surface concentration and cleavage domain type influenced the release of the model drug (BSA) from these NPs. This stratagem may provide a novel pathway for developing multi-functional coatings for controlling the local delivery of therapeutics at sites where the presence of various enzymes exist as a function of tissue state.

Spectroscopic ellipsometry of mucin layers on an amphiphilic diblock copolymer surface.

Both 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. After applying the regularized method of deconvolution in the analysis, the formation of hydrogen bonds between the carboxyl groups of the BSM and PAA-b-PMMA copolymer in double layers has been found. The IR ellipsometry data, in agreement with the visible ellipsometry analysis, indicate the pH dependence of adhesion of mucin to the copolymer surface. There is an increase in the amount of hydrogen-bonded carboxyl groups in mucin deposited at a pH of 3. There is no evidence that the amide groups of the mucin participate in this bonding. At the lower pH, the IR ellipsometry spectra after deconvolution reveal an increase in the proportion of beta-sheets in the BSM upon adsorption on the copolymer surface, indicating a more unfolded, aggregated structure. The IR ellipsometry data also indicated some changes in the conformational states of the side groups in the copolymer induced by entanglements and bonding interactions with the mucin macromolecules. Deconvolution provides an unprecedented level of information from the IR ellipsometry spectra and yields important insights.

Absorption of cetylpyridinium chloride into poly(N-isopropylacrylamide)-based microgel particles, in dispersion and as surface-deposited monolayers.

The 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. Various mechanisms for CPC absorption into the microgel particles are postulated, including electrostatic, polar, and hydrophobic interactions. A comparison has also been made between the effect of added CPC on the hydrodynamic diameter of free microgel particles in dispersion, determined by dynamic light scattering, and the thickness of adsorbed monolayers of the same microgel particles deposited on cationically modified, oxidized silicon surfaces, as determined from ellipsometry measurements. The trends observed in both cases are broadly similar. This work opens the way for development of microgel layers for controlled uptake and release applications.

Swelling and deswelling of adsorbed microgel monolayers triggered by changes in temperature, pH, and electrolyte concentration.

The 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). No actual desorption of the microgel particles was evident on changing the conditions, but a swelling/deswelling transition was observed around 32 degrees C. The thickness of the monolayer has been compared with the hydrodynamic diameter of the free microgel particles, dispersed in aqueous solution. For the poly(N-isopropylacrylamide) microgel particles, without any bulk ionisable comonomer groups present, the temperature dependence of the ellipsometric thickness of the monolayer mirrors closely that of the hydrodynamic diameter of the free particles. When ionizable (-COOH) groups are introduced into the microgel particles, however, this correspondence is largely lost because the microgel particles forming the deposited monolayer now contract strongly onto the oppositely charged substrate surface.