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Microplastic contamination has become a problem, as plastic production has increased worldwide. Microplastics are plastics with particles of less than 5 mm and are absorbed through soil, water, atmosphere, and living organisms and finally affect human health. However, information on the distribution, toxicity, analytical methods, and removal techniques for microplastics is insufficient. For clear microplastic analytical methods and removal technologies, this article includes the following: (1) The distribution and contamination pathways of microplastics worldwide are reviewed. (2) The health effects and toxicity of microplastics were researched. (3) The sampling, pretreatment, and analytical methods of microplastics were all reviewed through various related articles. (4) The various removal techniques of microplastics were categorized by wastewater treatment process, physical treatment, chemical treatment, and biological treatment. This paper will be of great help to microplastic analysis and removal techniques.

The forward osmosis (FO) and reverse osmosis (RO) hybrid process uses seawater and wastewater treatment plant effluent as the FO draw solution and feed water, respectively, and the diluted seawater by FO is used as the RO feed water resulting in the less energy consumption than the conventional seawater reverse osmosis applications. This work developed an optimal design approach of the hybrid process by finding the optimal RO recovery and FO permeate flow rate. The optimized RO recovery (e.g. 38.5–66.7% according to the FO permeate flow rate) determined by solving an optimization problem based on the mass balance in the FO-RO hybrid process, minimizes the RO energy consumption (1.86–3.49 kWh/m3 at 25°C and 2.41–3.86 kWh/m3 at 5°C). The RO energy consumption decreases as the RO recovery increases until it reaches an optimal value. The optimal FO permeate flow rate can be defined with three different perspectives: (1) to minimize the RO energy consumption, (2) to minimize the RO feed flow rate, and ...

In the real-field application, the operation conditions for seawater reverse osmosis (SWRO) processes such as pressure, temperature, recovery rate, and feed concentration vary, which changes the permeate flow rate with no fouling. In order to detect fouling from the fluctuating permeate flow rates due to various operation conditions, they should be normalized. However, the normalization method using ASTM D4516 method still produces the fluctuation in the normalized permeate flow due to poor selections of osmotic pressure and temperature correction factor (TCF) equations, which do not reflect the characteristics of feed water and reverse osmosis membrane in the field very well. This work introduces the corrected normalized permeate flux (NPF) using the fitted osmotic pressure and TCF equations to minimize the fluctuation during a non-fouling situation and suggests a statistical approach to detect fouling by comparing the mean values of two groups with different variances. The laboratory-scale SWRO ...

The removal of boron is a very important issue in desalination using seawater reverse osmosis (SWRO). A novel approach using polyol compounds to remove boron is introduced in this study. Polyols are compounds possessing multiple hydroxyl groups and they can combine with uncharged boric acid by generating anionic complexes. As a result, a large molecule is formed and it can be easily rejected by SWRO membrane at seawater pH. Lab-scale SWRO tests were performed to investigate the effect of polyol on the boron removal using different types of polyol (xylitol, glycerol, and D-mannitol). The polyol–boron reaction occurs in seawater condition with low boron concentration and various ion compounds, which leads to two important findings that boron-polyol reaction occurs with low boron and polyol concentrations, and there are no significant inhibitors for the reaction in seawater. The boron-polyol reaction rate is so fast that it can be easily applied to full-scale SWRO processes. The boron removal rate in...

In reverse osmosis (RO) process, chlorine is used in a pretreatment process to inhibit biofouling, however, its residual should be eliminated by using sodium bisulfite (SBS) before the RO process because polyamide (PA) RO membrane is damaged by free chlorine contact. In a field application, there always exists a risk that SBS injection pump is out of order so that PA membrane may be damaged by the residual chlorine. The objective of this work is to quantitatively investigate the effect of residual chlorine attack on the water flux and salt rejection of PA membrane. Lab-scale RO tests were performed to see changes in water flux and salt rejection by adding sodium hypochlorite and SBS. With a small concentration of residual chlorine and pH of 6–7, chlorination of aromatic rings in PA membrane induced a sharp flux decline at the beginning of the chlorination followed by a gradual decline. The additional exposure of chlorinated PA membrane to a high concentration (300 ppm) of residual chlorine induces...

A variety of masses in the knee must be considered in a differential diagnosis when swelling, pain, and a limitation of motion occur with no history of specific trauma. These lesions are most commonly related to the synovial lining of the joint capsule and the cruciate ligaments. The posterior compartment is an unusual location for solitary lesions of the knee joint. There have been few cases of abscess presenting as an intra-articular nodular mass. We report herein a case of a 15-year-old girl who had synovitis and an abscess nodule of the posterior compartment behind the posterior cruciate ligament in the knee joint. An arthroscopic synovectomy and mass excision along with antibiotic administration was curative in our case.

The xeroderma pigmentosum C (XPC) complex initiates nucleotide excision repair by recognizing DNA lesions before recruiting downstream factors. How XPC detects structurally diverse lesions embedded within normal DNA is unknown. Here we present a crystal structure that captures the yeast XPC orthologue (Rad4) on a single register of undamaged DNA. The structure shows that a disulphide-tethered Rad4 flips out normal nucleotides and adopts a conformation similar to that seen with damaged DNA. Contrary to many DNA repair enzymes that can directly reject non-target sites as structural misfits, our results suggest that Rad4/XPC uses a kinetic gating mechanism whereby lesion selectivity arises from the kinetic competition between DNA opening and the residence time of Rad4/XPC per site. This mechanism is further supported by measurements of Rad4-induced lesion-opening times using temperature-jump perturbation spectroscopy. Kinetic gating may be a general mechanism used by site-specific DNA-binding proteins to minimize time-consuming interrogations of non-target sites., XPC nucleotide excision repair factor is key to starting the repair of diverse helix-distorting DNA lesions caused by environmental insults. Here, the authors propose a kinetic gating mechanism whereby XPC recognizes DNA lesions by preferentially opening damaged sites while readily diffusing away from undamaged sites.

A full-scale model was developed to find optimal design parameters for osmotic membrane bioreactor (OMBR) and reverse osmosis (RO) hybrid system for wastewater reclamation. The model simulates salt accumulation, draw solution dilution and water flux in OMBR with sludge concentrator for high retention and low salt concentration factor. The full-scale OMBR simulation results reveal that flat-sheet module with spacers exhibits slightly higher flux than hollow-fiber; forward osmosis (FO) membrane with high water permeability, low salt permeability, and low resistance to salt diffusion shows high water flux; an optimal water recovery around 50% ensures high flux and no adverse effect on microbial activity; and FO membrane cost decreases and RO energy consumption and product water concentration increases at higher DS flow rates and concentrations. The simulated FO water flux and RO energy consumption ranges from 3.03 to 13.76LMH and 0.35 to 1.39kWh/m(3), respectively.

5-methylcytosine is an epigenetic mark that affects a broad range of biological functions in mammals. The chemically inert methyl group prevents direct labelling for subsequent affinity purification and detection. Therefore, most current approaches for the analysis of 5- methylcytosine still have limitations of being either density-biased, lacking in robustness and consistency, or incapable of analysing 5-methylcytosine specifically. Here we present an approach, TAmC-Seq, which selectively tags 5-methylcytosine with an azide functionality that can be further labelled with a biotin for affinity purification, detection and genome-wide mapping. Using this covalent labelling approach, we demonstrate high sensitivity and specificity for known methylated loci, as well as increased CpG dinucleotide coverage at lower sequencing depth as compared with antibody-based enrichment, providing an improved efficiency in the 5-methylcytosine enrichment and genome-wide profiling.

SummaryThe study of 5-hydroxylmethylcytosines (5hmC) has been hampered by the lack of a method to map it at single-base resolution on a genome-wide scale. Affinity purification-based methods cannot precisely locate 5hmC nor accurately determine its relative abundance at each modified site. We here present a genome-wide approach, Tet-assisted bisulfite sequencing (TAB-Seq), that when combined with traditional bisulfite sequencing can be used for mapping 5hmC at base resolution and quantifying the relative abundance of 5hmC as well as 5mC. Application of this method to embryonic stem cells not only confirms widespread distribution of 5hmC in the mammalian genome but also reveals sequence bias and strand asymmetry at 5hmC sites. We observe high levels of 5hmC and reciprocally low levels of 5mC near but not on transcription factor-binding sites. Additionally, the relative abundance of 5hmC varies significantly among distinct functional sequence elements, suggesting different mechanisms for 5hmC deposition and maintenance.