Assessment of Indoor Microbial Environment of Labs and Faculty Offices at a University in Gaza, Palestine

Bacteria and fungi grow indoors when sufficient moisture is available, causing indoor air pollution. The aims of this study were to determine the total viable bacterial count and fungi levels at the l... abs and faculty offices of the Islamic University of Gaza (IUG). Twenty-six air samples were collected from the IUG labs and faculty offices using air samplers. The results show that the highest bacterial count was observed at the Medical Science Labs with 1365 colony-forming unit (CFU)/m3 while the highest fungal count was detected at the Environment Science Labs with 425 CFU/m3. The majority of the monitored labs and offices have higher bacterial and fungal levels than the WHO standards of 500 CFU/m3. Lab users should wear face masks to reduce any potential health impacts due to the microbial pollution. 続きを見

Adsorption of Nonylphenol to Multi-Walled Carbon Nanotubes: Kinetics and Isotherm Study

We explored the occurrence and distribution of nonylphenol (NP) in 13 Taiwanese source waters. From all the surveyed waters, NP was detected at a high concentration, which could be attributed to contamination by wastewater discharges. In this study, we applied modified multi-walled carbon nanotubes (MWCNTs) for removing NP from aqueous solution. The impact of a few experimental factors, i.e., pH, contact time, MWCNTs dose, and temperature on the NP removal efficiency of modified MWCNTs was studied. The maximum adsorption capacity of the MWCNTs was observed to be 1040 mg NP/g when the initial NP concentration was 2.5 mg/L, and the solution pH was 4. The adsorption process followed the Elovich kinetics and the Elovich isotherm, indicating it is multilayer adsorption. The thermodynamic analysis demonstrated the NP adsorption by MWCNTs was thermodynamically satisfactory and, for the most part, endothermic as in the case of phenol adsorption. The result of the current study demonstrated the significance of free binding sites and the pore size of MWCNTs in the NP adsorption. This paper will help to better comprehend the adsorption behavior and mechanism of alkyl phenolic compounds onto MWCNTs

Simultaneous capturing of mixed contaminants from wastewater using novel one-pot chitosan functionalized with EDTA and graphene oxide adsorbent

The emergence of inorganic and organic contaminants has raised great concerns owing to their adverse impact on human health and ecological security. Herein, first time one-pot process was applied for chitosan (CS) functionalization using graphene oxide (GO) and ethylenediaminetetraacetic acid (EDTA) for simultaneous capturing of toxic inorganic (lead (Pb2+) and cadmium (Cd2+)) and organic (ciprofloxacin (CIP) and sildenafil (SDF)) contaminants from wastewater. In this approach, we believe that CS would work as a backbone, GO would capture both inorganic and organic contaminants via electrostatic interactions, while EDTA would make complexation with heavy metals. Various parameters including pH, reaction time, concentration, reusability etc. were evaluated to achieve the best experimental result in monocomponent system. The prepared adsorbent displayed an excellent monolayer adsorption capacity of 351.20 and 264.10 mg g−1 for Pb2+ and Cd2+, respectively, while a heterogeneous sorption capacity of 75.40 and 40.90 mg g−1 for CIP and SDF, respectively. The kinetics data fitted well to Pseudo-second order (PSO) kinetics model for both types of contaminants and gave faster interaction towards metal ions (higher k2) than organic contaminants. Experimental results showed excellent adsorption efficiencies at environmental levels in the capturing of both inorganic and organic contaminants at the same time from polluted water. The capturing mechanism of both types of contaminants was explained by elemental mapping, EDS, and FT−IR spectra. Overall, easy synthesis, excellent capturing capacity, and reusability imply that the prepared adsorbent has a sufficient potential for the treatment of co-existing toxic contaminants in water

Fatal systemic disorder caused by biallelic variants in FARSA

Background : Aminoacyl tRNA transferases play an essential role in protein biosynthesis, and variants of these enzymes result in various human diseases. FARSA, which encodes the α subunit of cytosolic phenylalanyl-tRNA synthetase, was recently reported as a suspected causal gene for multiorgan disorder. This study aimed to validate the pathogenicity of variants in the FARSA gene. Results : Exome sequencing revealed novel compound heterozygous variants in FARSA, P347L and R475Q, from a patient who initially presented neonatal-onset failure to thrive, liver dysfunction, and frequent respiratory infections. His developmental milestones were nearly arrested, and the patient died at 28 months of age as a result of progressive hepatic and respiratory failure. The P347L variant was predicted to disrupt heterodimer interaction and failed to form a functional heterotetramer by structural and biochemical analyses. R475 is located at a highly conserved site and is reported to be involved in phenylalanine activation and transfer to tRNA. The R475Q mutant FARSA were co-purified with FARSB, but the mutant enzyme showed an approximately 36% reduction in activity in our assay relative to the wild-type protein. Additional functional analyses on variants from previous reports (N410K, F256L, R404C, E418D, and F277V) were conducted. The R404C variant from a patient waiting for organ transplantation also failed to form tetramers but the E418D, N410K, F256L, and F277V variants did not affect tetramer formation. In the functional assay, the N410K located at the phenylalanine-binding site exhibited no catalytic activity, whereas other variants (E418D, F256L and F277V) exhibited lower ATPase activity than wild-type FARSA at low phenylalanine concentrations. Conclusions : Our data demonstrated the pathogenicity of biallelic variants in FARSA and suggested the implication of hypomorphic variants in severe phenotypes.This study was supported by a research program funded by the Korea Disease Control and Prevention Agency (Grant Nos. 2021-ER0701-00 and 2020-ER6902-00)

Determination of NH4+ in Environmental Water with Interfering Substances Using the Modified Nessler Method

Nitrogen is an essential element in the environment. If excess nitrogen including NH4 + is present in water, however, it can result in algae blooming and eventually the destruction of the aquatic ecosystem. Therefore, the determination of NH4 + in streams, lakes, and effluents of the treatment facilities has long been carried out. The Nessler method is the most common spectrophotometric method to measure NH4 + in water. However, the result of the method becomes inaccurate if there are interfering substances such as Cl2, Cl−, hardness-causing compounds (e.g., Mg2+), and Fe2+ in target water samples. In this study, therefore, the traditional Nessler method has been modified to eliminate the effects of interfering substances; the so-called MS was added to water samples. In addition, the polyvinyl alcohol reagent as a dispersing agent was added to water samples to increase the sensitivity and reproducibility of the method. The modified method could successfully analyze NH4 + of water samples even with the interfering substance at high concentration

Estimation of Biochemical Oxygen Demand Based on Dissolved Organic Carbon, UV Absorption, and Fluorescence Measurements

Determination of 5-d biochemical oxygen demand (BOD5) is the most commonly practiced test to assess the water quality of surface waters and the waste loading. However, BOD5 is not a good parameter for the control of water or wastewater treatment processes because of its long test period. It is very difficult to produce consistent and reliable BOD5 results without using careful laboratory quality control practices. This study was performed to develop software sensors to predict the BOD5 of river water and wastewater. The software sensors were based on the multiple regression analysis using the dissolved organic carbon (DOC) concentration, UV light absorbance at 254 nm, and synchronous fluorescence spectra. River water samples and wastewater treatment plant (WWTP) effluents were collected at 1-hour interval to evaluate the feasibility of the software sensors. In short, the software sensors developed in this study could well predict the BOD5 of river water (r=0.78) and for the WWTP effluent (r=0.90)

Development of Software Sensors for Determining Total Phosphorus and Total Nitrogen in Waters

Total nitrogen (TN) and total phosphorus (TP) concentrations are important parameters to assess the quality of water bodies and are used as criteria to regulate the water quality of the effluent from a wastewater treatment plant (WWTP) in Korea. Therefore, continuous monitoring of TN and TP using in situ instruments is conducted nationwide in Korea. However, most in situ instruments in the market are expensive and require a time-consuming sample pretreatment step, which hinders the widespread use of in situ TN and TP monitoring. In this study, therefore, software sensors based on multiple-regression with a few easily in situ measurable water quality parameters were applied to estimate the TN and TP concentrations in a stream, a lake, combined sewer overflows (CSOs), and WWTP effluent. In general, the developed software sensors predicted TN and TP concentrations of the WWTP effluent and CSOs reasonably well. However, they showed relatively lower predictability for TN and TP concentrations of stream and lake waters, possibly because the water quality of stream and lake waters is more variable than that of WWTP effluent or CSOs

Evaluation of the Effectiveness of Five Odor Reducing Agents for Sewer System Odors Using an On-Line Total Reduced Sulfur Analyzer

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EFFECT OF NATURAL ORGANIC MATTER ON ADSORPTION OF IONIC AND NON-IONIC PHARMACEUTICALS TO GRANULAR ACTIVATED CARBON

Adsorption of clofibric acid (CA) and propyphenazone (PPZ) to virgin granular activated carbon (GAC) and preloaded GAC was evaluated in the absence or presence of natural organic matter (NOM). In spite of lower log K ow , PPZ showed higher selectivity to GAC than CA, which has a carboxylic group. Adsorption competition between CA and PPZ in binary solutes system decreased the amount of individual compound adsorbed to GAC. Adsorption isotherm data obtained in the presence of NOM showed that NOM in bulk solution or preloaded on GAC could significantly reduce the amounts of CA and PPZ adsorbed to GAC