Chitosan Polymer Functionalized-Activated Carbon/Montmorillonite Composite for the Potential Removal of Lead Ions from Wastewater.

A simple approach for synthesizing a highly adsorbent composite was described for the uptake of heavy metal ions from wastewater. A simple approach for synthesizing a highly adsorbent composite was also described for the elimination of heavy metal ions from contaminated water. The nanocomposite was synthesized via a polymer grafting of chitosan on the activated carbon surface, followed by a stacking process with the layers of montmorillonite clay. The spectroscopic analyses were exploited to confirm the composite structure of the prepared materials. Various adsorption parameters, such as pH, initial concentration, and adsorption time, were assessed. The results showed that the adsorption capacity of the composite for Pb2+ ions increased as the pH increased until it reached pH 5.5. The maximum adsorption capacity was observed at an initial Pb2+ level of 20 mg/L and a contact time of 150 min. Kinetic models were evaluated, and the pseudo second-order model showed the best match. The adsorption isotherm data were processed by fitting the model with different isotherm behaviors, and the Langmuir isotherm was found to be the most suitable for the system. The maximum adsorption capacity for Pb2+ ion on the MMT/CS/AC composite was found to be 50 mg/g at pH 5.5. Furthermore, the composite maintained a high adsorption capability of 85% for five adsorption-desorption cycles. Overall, this composite is envisioned as an addition to the market of wastewater remediation technology due to its chemical structure, which provides influential functional groups for wastewater treatment.

The Prevalence of Nomophobia and Its Impact on Academic Performance of Medical Undergraduates at the College of Medicine, Umm Al-Qura University, Makkah City, Saudi Arabia.

BACKGROUND: Nomophobia, or no mobile phone phobia, is a term used to describe psychological conditions when people fear being without a mobile phone. OBJECTIVES: This study aimed to measure the prevalence of nomophobia, its associated factors, and its impact on the academic performance of medical undergraduates at Umm Al-Qura University (UQU), Makkah City, Saudi Arabia. METHODS: A descriptive cross-sectional study included a simple random sample of 595 medical undergraduates. The study administered the Nomophobia Questionnaire, which had been validated in previous articles, using an interview-based model. The collected data were reviewed and entered into the IBM SPSS Statistics for Windows, Version 26 (Released 2019; IBM Corp., Armonk, New York) for analysis. RESULTS: A total of 595 medical students were included in this study. Most of them (99%, n = 589) had different degrees of nomophobia, while only a small percentage (1%, n = 6) did not exhibit it. The younger medical students (18-19 years old) showed significantly higher percentages of moderate to severe nomophobia in comparison to older students (P = 0.028), while there was no significant relationship between nomophobia and academic performance, despite the fact that 128 (77.1%) of students with severe nomophobia had grade point averages (GPAs) of 3.5-4.0, compared to 244 (69.1%) of students with moderate nomophobia (P = 0.150). CONCLUSIONS: This study concludes that the prevalence rate of nomophobia is generally high among medical undergraduates at UQU in Makkah City, Saudi Arabia. This disorder was detected more among younger medical undergraduates, with no significant effects on their academic performance. It is mandatory to conduct more studies with larger sample sizes of different university students (medical and non-medical) to identify factors that lead to the development of nomophobia. Qualitative research among groups of university students will add more deep information about this disorder. Health education programs should be designed and targeted at university students, focusing on the harmful health effects of excessive use of mobile phones and measures to prevent this disorder.

Oral administration of a potassium bromate dosage: Determination and evaluation of accumulated bromate on the liver of male mice.

In this work, we developed a simple spectrophotometric strategy for BrO3- ions determination as a major water disinfection constituents in the mice's liver tissues by using pararosaniline (PRA). Mice were divided into seven main groups (6 doses): lowest dose KBrO3 (G1 0.01 mg L-1, G2 0.025 mg L-1 and G3 0.1 mg L-1), highest dose KBrO3 (G4 1 mg L-1, G5 10 mg·L-1 and G6 30 mg L-1) and control. All these groups maintained a dose-specific feeding for one month, just before the bromate assessment in mice's liver samples. The results revealed that groups of exposure to lower doses of drinking water did not detect the presence of BrO3- accumulated in the liver tissue during the study period (1-2 months). While, the BrO3- was detected in higher dosages for samples analyzed in first, second, third, fourth and fifth weeks (W1, W2, W3, W4, and W5). These results confirmed that the higher BrO3- dosages (1, 10, and 30 mg L-1) were fatal if introduced in drinking water and could accumulate in the liver tissues both for mice and for human. Detection the accuracy of the method for recovery of bromate ions in liver samples (N = 5) was found to be more than 95%. Relative standard deviations (RSDs) were found to be less than 2.0% confirming the reproducibility of the assay technique.

Analysis of mandibular premolar root position in relation to adjacent cortical plates and mental foramen using cone beam computed tomography in the Saudi population.

OBJECTIVES: To evaluate the horizontal and vertical location of the mental foramen (MF), as well as the relationship of lower premolars to buccal and lingual cortical plates using cone beam computed tomography (CBCT). Methods: Retrospective cross-sectional study conducted using CBCT scans that were obtained between early 2014 and late 2016 from King Saud University Dental hospital database in Riyadh, Kingdom of Saudi Arabia; 94 patients (53 males and 41 females) were included. Three examiners independently performed one-sided measurements for each patient. Data analyzed statistically and a p less than 0.05 was considered significant. Results: The mean distances from the outer boundary of the buccal cortex to the first and second premolars (R1) were 1.55 mm and 1.98 mm. The mean distances from the outer boundary of the lingual cortical plate to the first and second premolars (R2) were 4.06 mm and 4.73 mm. The respective mean total bone thicknesses, including the roots of the first and second premolars (R3), were 9.32 mm and 10.08 mm. The mean distance between the MF and the mandibular second premolar apex was 3.13 mm. Conclusion: Mandibular premolars are in close proximity to MF especially mandibular second premolar. Presurgical assessment is essential when surgical treatment is planned at this area.

An analysis of the first and second mandibular molar roots proximity to the inferior alveolar canal and cortical plates using cone beam computed tomography among the Saudi population.

OBJECTIVES: To evaluate the relationship of the first and second mandibular molar roots to the inferior alveolar canal (IAC) and cortical plates using cone beam computed tomography (CBCT) in the Saudi population. Methods: Scans of 60 patients were collected retrospectively from the dental hospital database in King Saud University, Riyadh, Kingdom of Saudi Arabia. Measurements of the right and left first and second mandibular molars for each dental root and the mandibular bone thickness were determined. The position of the IAC was estimated using axial, coronal, and sagittal views. Three examiners performed the measurements independently. RESULTS: The mean distance between the root apices of the mandibular molars and the IAC ranged from 1.68-4.79 mm, whereas the mean distance from the outer surface of the buccal cortical plate to the buccal root surface ranged from 2.33-6.72 mm. Similarly, the mean distance from the outer surface of the lingual cortical plate to the lingual root surface ranged from 2.62-4.80 mm. Finally, the mean distance from the outer surface of the lingual cortical plate to the outer surface of the buccal cortical plate was 11.93-13.19 mm. Conclusion: The measurements reported in this study may be of value to practitioners treating Saudi patients, as they need to be familiar with the distance of the mandibular first and second molars in relation to the IAC and surrounding cortical plates to accurately assess and plan endodontic surgeries, surgical extractions, and implant placements.

Mercerized mesoporous date pit activated carbon-A novel adsorbent to sequester potentially toxic divalent heavy metals from water.

A substantive approach converting waste date pits to mercerized mesoporous date pit activated carbon (DPAC) and utilizing it in the removal of Cd(II), Cu(II), Pb(II), and Zn(II) was reported. In general, rapid heavy metals adsorption kinetics for Co range: 25-100 mg/L was observed, accomplishing 77-97% adsorption within 15 min, finally, attaining equilibrium in 360 min. Linear and non-linear isotherm studies revealed Langmuir model applicability for Cd(II) and Pb(II) adsorption, while Freundlich model was fitted to Zn(II) and Cu(II) adsorption. Maximum monolayer adsorption capacities (qm) for Cd(II), Pb(II), Cu(II), and Zn(II) obtained by non-linear isotherm model at 298 K were 212.1, 133.5, 194.4, and 111 mg/g, respectively. Kinetics modeling parameters showed the applicability of pseudo-second-order model. The activation energy (Ea) magnitude revealed physical nature of adsorption. Maximum elution of Cu(II) (81.6%), Zn(II) (70.1%), Pb(II) (96%), and Cd(II) (78.2%) were observed with 0.1 M HCl. Thermogravimetric analysis of DPAC showed a total weight loss (in two-stages) of 28.3%. Infra-red spectral analysis showed the presence of carboxyl and hydroxyl groups over DPAC surface. The peaks at 820, 825, 845 and 885 cm-1 attributed to Zn-O, Pb-O, Cd-O, and Cu-O appeared on heavy metals saturated DPAC, confirmed their binding on DPAC during the adsorption.