The fate of cadmium at the Muharram Aisha wastewater treatment plant in Karbala governorate, Iraq was studied using the TOXCHEM model. Cadmium, a known carcinogen, and is considered one of the most ...dangerous heavy metals and high concentrations, greater than permissible limits, were found in the treated wastewater. The plant operates using an activated sludge system and this was modeled via TOXCHEM with a sensitivity analysis carried out on the extended aeration system. Prior to analysis, the model was calibrated and validated for cadmium, with the adjustments leading to a mean square error (RMSE) and correlation coefficient (R) of 0.0001 and 0.81, respectively. The mass balance of cadmium in the Muharram Aisha treatment plant was found to be 4832.44 g/day (37.1726%) in the treated wastewater and 8164.52 g/day (62.804%) in the sludge, which indicated that the mix liquor suspended solid (MLSS) was the most sensitive factor. The sensitivity to cadmium was analyzed via MLSS in the extended aeration system and the results o indicated that the higher the MLSS concentration (mg/L), the greater the removal of cadmium in the treated wastewater. It was found that increasing the MLSS through a biological treatment method reduced the concentration of cadmium without the need for additional of any (potentially harmful) chemical treatments. The plant was subsequently operated for a period of 5 months with the MLSS increased from 1500 to 4500 mg/L, and this reduced the concentration of cadmium in the wastewater from 0.36 to 0.01 mg/L as a consequence. This research demonstrates how the novel application of TOXCHEM can be a useful tool in the reduction of heavy metal contamination in the environment.
Odors due to the emission of hydrogen sulfide (H
S) have been a concern in the sewage treatment plants over the last decades. H
S fate and emissions from extended aeration activated sludge (EAAS) ...system in Muharram Aisha-sewage treatment plant (MA-STP) were studied using TOXCHEM model. Sensitivity analysis at different aeration flowrate, H
S loading rate, wastewater pH, wastewater temperature and wind speed were studied. The predicted data were validated against actual results, where all the data were validated within the limits, and the statistical evaluation of normalized mean square error (NMSE), geometric variance (VG), and correlation coefficient (R) were close to the ideal fit. The results showed that the major processes occurring in the system were degradation and emission. During summer (27 °C) and winter (12 °C), about 25 and 23%, 1 and 2%, 2 and 2%, and 72 and 73% were fated as emitted to air, discharged with effluent, sorbed to sludge, and biodegraded, respectively. At summer and winter, the total emitted concentrations of H
S were 6.403 and 5.614 ppm, respectively. The sensitivity results indicated that aeration flowrate, H
S loading rate and wastewater pH highly influenced the emission and degradation of H
S processes compared to wastewater temperature and wind speed. To conclude, TOXCHEM model successfully predicted the H
S fate and emissions in EAAS system.
The novel process consisted of two steps was established by combining all sidestreams lines (supernatant gravity thickener, underflow mechanical thickener, and centrate), treating them together away ...from the mainstream treatment plant, and returning treated sidestreams effluents to the plant outfall instead of plant head. The two steps novelty treatment combined degradation, nitrification, and dilution processes. To treat combined sidestreams, a novel pilot extended nutrient moving bed biofilm reactor was developed. The effects of sidestream elimination on a full-scale anaerobic/anoxic/oxic system were simulated using GPS-X7. The statistical results of R values greater than 0.8 and NMSE values near zero proved the calibrated model's validation. The novel system successfully removed 98, 93, 100, 85, 98, 100, and 98% of BOD, COD, NH
, NO
, TSS, H
S, and PO
-P from sidestreams, respectively. Furthermore, the simulation results showed that eliminating sidestreams has reduced volumes of full-scale A
/O facilities, controlled hydraulic and pollutants shocks, and minimized cost and energy. The novel process proved successful in treating combined sidestreams and eliminating their impacts on the A/O
system.
The authors’ objectives are to investigate the therapeutic effect of alkaloid extract of cyanobacteria
Spirulina platensis
on the lipid profile of hypercholesterolemic male rabbits and to identify ...the active compounds in the alkaloid extract. Male rabbits were divided into four groups of six animals. The intact rabbits in the first group served as a negative control. The second group served as a positive control (hypercholesterolemic rabbits). Over a 4-week period, hypercholesterolemic rabbits in the third group received a low dose of alkaloid extract (33 mg/kg), and the hypercholesterolemic rabbits in the fourth group received a high dose (66 mg/kg). The results revealed that both doses of alkaloid extract significantly decreased levels of cholesterol, triglycerides, low-density lipoproteins (LDL), and very low-density lipoproteins (VLDL) when compared to the control group, whereas the high-density lipoproteins (HDL) increased significantly compared to the control group. The active compounds in the alkaloid extract were identified using GC-mass. The most abundant compounds found in the extract were 1-(+)-ascorbic acid 2,6-dihexadecanoate, 9,12-octadecadienoic acid (Z, Z)-, hexadecanoic acid, 2-hydroxy-1- (hydroxymethyl) ethyl ester, and gamolenic acid.
Catechin is a naturally occurring flavonoid of the flavan-3-ol subclass with numerous biological functions; however, these benefits are diminished due to several factors, including low water ...solubility and degradation in the stomach's harsh environment. So, this study aimed to develop an intelligent catechin colon-targeting delivery system with a high loading capacity. This was done by coating surface-decorated mesoporous silica nanoparticles with a pH-responsive enteric polymer called Eudragit®-S100. The pristine wormlike mesoporous silica nanoparticles (< 100 nm) with high surface area and large total pore volume were effectively synthesized and modified with the NH2 group using the post-grafting strategy. Various parameters, including solvent polarity, catechin-carrier mass ratio, and adsorption time, were studied to improve the loading of catechin into the aminated silica nanoparticles. Next, the negatively charged Eudragit®-S100 was electrostatically coated onto the positively charged aminated nanocarriers to shield the loaded catechin from the acidic environment of the stomach (pH 1.9) and to facilitate site-specific delivery in the acidic environment of the colon (pH 7.4). The prepared nanomaterials were evaluated using several methods, including The Brauner-Emmett-Teller, surface area analyzer, zeta sizer, Field Emission Scanning Electron Microscope, Powder X-Ray Diffraction, Fourier Transform Infrared Spectroscopy, Energy-Dispersive X-ray Spectroscopy, and Differential Scanning Calorimetry. In vitro dissolution studies revealed that Eudragit®-S100-coated aminated nanomaterials prevented the burst release of the loaded catechin in the acidic environment, with approximately 90% of the catechin only being released at colonic pH (pH > 7) with a supercase II transport mechanism. As a result, silica nanoparticles coated with Eudragit®-S100 would provide an innovative and promising approach in targeted nanomedicine for the oral delivery of catechin and related medicines for treating diseases related to the colon, such as colorectal cancer and irritable bowel syndrome.
Display omitted
Isoflavenes have received the greatest research attention among the many groups of phytoestrogens. In this study, various isoflavene-based Mannich bases were selected for their theoretical studies. ...The purpose of this research was to discover the binding potential of all the designated Mannich bases acting as inhibitors against cancerous proteins EGFR, cMet, hTrkA, and HER2 (PDB codes: 5GTY, 3RHK, 6PL2, and 7JXH, respectively). For their virtual screening, DFT calculations and molecular docking studies were undertaken using in silico software. Docking studies predicted that ligands 5 and 15 exhibited the highest docking score by forming hydrogen bonds within the active pocket of protein 6PL2, ligands 1 and 15 both with protein 3RHK, and 7JXH, 12, and 17 with protein 5GTY. Rendering to the trends in polarizability and dipole moment, the energy gap values (0.2175 eV, 0.2106 eV) for the firm conformers of Mannich bases (1 and 4) replicate the increase in bioactivity and chemical reactivity. The energy gap values (0.2214 eV and 0.2172 eV) of benzoxazine-substituted isoflavene-based Mannich bases (9 and 10) reflect the increase in chemical potential due to the most stable conformational arrangements. The energy gap values (0.2188 eV and 0.2181 eV) of isoflavenes with tertiary amine-based Mannich bases (14 and 17) reflect the increase in chemical reactivity and bioactivity due to the most stable conformational arrangements. ADME was also employed to explore the pharmacokinetic properties of targeted moieties. This study revealed that these ligands have a strong potential to be used as drugs for cancer treatment.
Simvastatin (SV) repurposing has emerged as an alternative approach for the treatment of cancer. In this study, SV chitosan nanoparticles co-crosslinked with tripolyphosphate and chondroitin sulfate ...(SVCSChSNPs) were developed in order to maximize SV therapeutic efficiency. The hepatic targeting was realized using N-acetylgalactosamine (GalNAc) residues of ChS, which can be identified by the ASGPR receptors specifically expressed in hepatocytes. SV was repurposed as an anticancer agent against hepatocellular carcinoma (HCC). NPs were fabricated by the ionic gelation method, and the formulation variables (CS concentration, CS:ChS ratio, and CS solution pH) were optimized using a three-factor, three-level Box-Behnken design. The optimized NPs were investigated for particle size, size distribution, zeta potential, morphology, in vitro cytotoxicity, apoptotic effects against human hepatocellular carcinoma HepG2 cells, and detection of intracellular localization. The NPs were further evaluated for in vitro release behavior of SV and pharmacokinetics using Wister albino rats. Transmission electron microscopy (TEM) imaging showed a spherical shape with regular surface NPs of < 100 nm diameter. In vitro cytotoxicity testing showed that the SVCSChSNPs exhibited greater inhibition of proliferation in HepG2 cells and high cellular uptake through ASGPR-mediated endocytosis. The in vitro dissolution profile was 2.1-fold greater than that of pure SV suspension. Furthermore, in vivo oral pharmacokinetics revealed that the obtained NPs enhanced the bioavailability of SV by up to 2- and 1.6-fold for SV and SVA, respectively, compared to the pure SV suspension. These findings demonstrated that hepatic-targeted CSChSNPs delivering SV could potentially serve as a promising platform for HCC and other liver-related diseases.
The increasing prevalence of distress among students is of global concern. Several factors such as school and family environment and ineffective study skills could influence mental health. The study ...explored the rate of distress symptoms among school students' and its relationship with their study skills, stressors and demographic factors.
In this cross-sectional analytical study, a sample of 215 students from a community school participated in the study. Three questionnaires, demographic questionnaire, Study Skills Inventory and the Kessler Psychological Distress Scale, were used for data collection. Data were analyzed using Student's
-test, ANOVA, Pearson's correlation coefficient and stepwise linear regression.
Response rate was 70% (n = 150). A high proportion of respondents (75%) was distressed (mean 27.28 ± 8.77). Correlation analysis showed that distress (K10 score) was negatively related to study skills (SSI total score) (r = -0.247, p = 0.002). The rate of distress symptoms was higher among female students (79%) compared to their male counterparts (72%). The factors associated with distress included negative association of teachers' level of help to develop competencies (p = 0.000, β = -0.278, R
= 0.249), unfavorable school environment (p = 0.000, β = 0.285, R
= 0.123), inability to cope with studies (p = 0.005, β = 0.205, R
= 0.038), family problems (p = 0.014, β = 0.184, R
= 0.173) and lower study skills (p = 0.031, β = -0.164, R
= 0.270). The overall regression analysis explained 33.6% of the variance (corrected R
= 0.336).
Higher than expected levels of distress (75%) was found in immigrant school students. Poor study skills have a significant relationship with distress. Learning environment and related stress factors were associated with distress among students. Based on the findings, it is recommended that stakeholders in education address the hidden curriculum, as it is usually unacknowledged and might affect students' wellbeing, and move from student centered to an interpersonal relation-centered education.
Display omitted
Worldwide, most treatment systems are retuning sidestreams to the wastewater treatment plant head without treatment. This study established an innovative process to separately treat ...all sidestream lines (supernatant gravity thickener, underflow mechanical thickener, and centrate) away from plant mainstream and return treated sidestream effluents to plant wastewater outfall instead of wastewater head. It aims to start up and operate a novel EN-MBBR to eliminate sidestreams impacts on a full-scale A2/O sewage treatment plant. The effects of DO, RAS, and media portion on the reactor were modeled using GPS-X. The system successfully started and reached a steady-state in 28 days. The pilot system processed 30 m3/d of the sidestreams, and the average of 8 months effluent concentrations for COD, BOD, TSS, PO4, NH4, NO2, NO3, H2S were 55, 4, 11, 0.16, 0.2, 0.17, 100, and 0.11 mg/L, respectively. Adding 3 kg/day of calcium hydroxide contributed to improving the nitrification process and reducing phosphates from 40 mg/L to 0.16 mg/L, but it caused an initial shock to the system that lasted more than a week, and then it was stabilized. Modeling results showed that DO concentrations affected the nitrification process but stabilized at a concentration of 3 mg/L. When operating the EN-MBBR as an EN-IFAS system, the RAS has positively contributed to reducing sludge in this system, whereas the sludge proportion is reduced by 60%. The media portion had a significant effect on the removal of nutrients, as it gave the best results when the rate of reactor filling with carriers was between 40 and 50%.
Aim
Several studies have shown high prevalence rates of sleep problems among medical students, including insufficient sleep duration, poor sleep quality, and excessive daytime sleepiness. This review ...aims to systematically summarize the existing literature on sleep problems among medical students and consequently estimate the prevalence of these disturbances.
Subject and Methods
The MEDLINE, EMBASE, ScienceDirect, and ProQuest Medical databases, the Google Scholar engine, and reference lists of retrieved articles were systematically searched and evaluated for quality.
Results
Forty–three studies involving a total of 18,619 students from 13 countries were included in the analyses. Results showed that the mean pooled sleep duration (K = 16,
N
= 10,512) was 6.3 h per night for medical students, 95% confidence interval (CI) 6.0–6.6. The results also indicated that 55% 95% CI 48.0%–62.0% of students reported poor sleep quality (K = 33,
N
= 15,462) according to the Pittsburgh Sleep Quality Index (PSQI); the mean pooled score of 6.3. Excessive daytime sleepiness (K = 18,
N
= 5688) was reported by 31.0% 95% CI 24.4%–37.7% of students according to the Epworth Sleepiness Scale (ESS). Age and gender were not significant moderators for sleep quality or excessive daytime sleepiness. Some differences were obtained between countries, suggesting that cultural values, local conditions, and environment all have an impact on sleep practices and attitudes.
Conclusion
Sleep problems are highly prevalent among medical students and are therefore a severe problem. Prevention and intervention programs targeting these are therefore highly recommended for future studies.
PDF
