CRISPR/Cas-mediated editing of cis-regulatory elements for crop improvement

To improve future agricultural production, major technological advances are required to increase crop production and yield. Targeting the coding region of genes via the Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated Protein (CRISPR/Cas) system has been well established and has enabled the rapid generation of transgene-free plants, which can lead to crop improvement. The emergence of the CRISPR/Cas system has also enabled scientists to achieve cis-regulatory element (CRE) editing and, consequently, engineering endogenous critical CREs to modulate the expression of target genes. Recent genome-wide association studies have identified the domestication of natural CRE variants to regulate complex agronomic quantitative traits and have allowed for their engineering via the CRISPR/Cas system. Although engineering plant CREs can be advantageous to drive gene expression, there are still many limitations to its practical application. Here, we review the current progress in CRE editing and propose future strategies to effectively target CREs for transcriptional regulation for crop improvement

Sustainable Polymers from Recycled Waste Plastics and Their Virgin Counterparts as Bitumen Modifiers: A Comprehensive Review

The failure of bituminous pavements takes place due to heavy traffic loads and weather-related conditions, such as moisture, temperature, and UV radiation. To overcome or minimize such failures, a great effort has been put in recent years to enhance the material properties of bitumen, ultimately improving field performance and increasing the pavement service life. Polymer modification is considered one of the most suitable and by far the most popular approach. Elastomers, chemically functionalised thermoplastics and plastomers * (* Note: notwithstanding the fact that in Polymer Science the word ‘plastomer’ indicates a polymer with the simultaneous behaviour of an elastomer and plastics (thermoplastics), this paper uses the term ‘plastomer’ to indicate a thermoplastic polymer as it is more commonly found in Civil and Pavement Engineering.) are the most commonly used polymers for bitumen modification. Plastomers provide several advantages and are commonly acknowledged to improve high-temperature stiffness, although some of them are more prone to phase separation and consequent storage instability. Nowadays, due to the recent push for recycling, many road authorities are looking at the use of recycled plastics in roads. Hence, some of the available plastomers—in pellet, flakes, or powder form—are coming from materials recycling facilities rather than chemical companies. This review article describes the details of using plastomers as bitumen modifiers—with a specific focus on recycled plastics—and how these can potentially be used to enhance bitumen performance and the road durability. Chemical modifiers for improving the compatibility between plastomers and bitumen are also addressed in this review. Plastomers, either individual or in combination of two or three polymers, are found to offer great stiffness at high temperature. Different polymers including HDPE, LDPE, LLDPE, MDPE, PP, PS, PET, EMA, and EVA have been successfully employed for bitumen modification. However, each of them has its own merit and demerit as thoroughly discussed in the paper. The recent push in using recycled materials in roads has brought new light to the use of virgin and recycled plastomers for bitumen modification as a low-cost and somehow environmental beneficial solution for roads and pavements

Recycling of low-value packaging films in bitumen blends: A grey-based multi criteria decision making approach considering a set of laboratory performance and environmental impact indicators

Many road construction and maintenance projects are increasingly using recycled material as pavement material. Most of the times, generic sustainability evaluations are ascribed to recycled products without fully considering their performance. The potential environmental benefits of various alternatives can be analytically evaluated with Life Cycle Assessment while many performance indicators can be found through laboratory and field tests. However, it is highly uncommon for these two approaches to be combined in the same assessment methodology and most of the analyses rely on one or the other. Trading off between environmental advantages and performance and durability in the field is considered of utmost importance when evaluating construction alternatives, especially on large projects. This study utilizes recycled plastic packaging films for bitumen modification. The recycled polyolefin blend is a combination of linear low-density polyethylene and low-density polyethylene (LLDPE/LDPE). LLDPE/LDPE was added in bitumen at various dosages (i.e., from 3% to 12% by weight of the bitumen) to assess the effect of recycled LLDPE/LDPE on the binder physio-chemical, rheological and thermal performance. In addition to the various laboratory performance tests, the environmental sustainability of the alternatives was evaluated through an LCA study. Finally, the outcomes from the two approaches (laboratory performance and environmental impact assessment) were combined via grey relational analysis to identify the best overall alternative. It was found that the storage stability of LLDPE/LDPE modified blends varied from 6 °C to 57 °C whereas the storage stability value of A35P was 2 °C. Softening point of bitumen was 44.1 °C which improved to 55.7–104.1 °C at different content of LLDPE/LDPE. The melting temperature of LLDPE/LDPE modified blends was 100.22, 101.44, 101.87 and 102.49 for LLDPE/LDPE-3%, LLDPE/LDPE-6%, LLDPE/LDPE-9% and LLDPE/LDPE-12%. The methodology highlighted in the paper can be easily adapted to other scenarios, hence facilitating multi-attribute decision-making processes when incorporating recycled materials in roads and leading to better informed decisions

Microwave-assisted synthesis of carbon nanotubes for the removal of toxic cationic dyes from textile wastewater

Toxic cationic dyes are used in different textile industries. When the colour interacts with the sunlight, it causes incomplete photosynthesis, inhibiting aquatic organisms’ growth and disrupting gas permeability in the water system. In this work, carbon nanotubes (CNTs) were prepared to employ acetylene and hydrogen as precursor gases in a microwave-assisted reactor. The obtained CNTs were tested for their ability to remove the crystal violet (CV) dye. However, the effect of removal parameters, such as pH of ion solution, initial concentration, and contact time, was optimized on the adsorption process through response surface methodology. It was found that the optimized removal of CV dye was 81% at an optimum pH value of 7.0 with 10 mg/L of an initial concentration and a contact time of 25 min. Complete dye extraction can be achieved by increasing the CNT dosage.Moreover, by using both the Langmuir model and Freundlich model of adsorption, the equilibrium data obtained from experiments were analyzed. The study also revealed that the adsorption at room temperature, having a high adsorption capability of 2.615 mg/g for CV, was best defined using the Langmuir model. For the reaction order, the adsorption rates represented the pseudo-first-order kinetic model

Graphene based nanomaterials for strain sensor application - a review

Strain Sensors have rapidly pervasived in modern era due to their ability to identify, respond and exchange mechanical motion into an electrical signal that can be interpreted on the basis of electrical resistance. As a matter of fact, strain sensors applications have expanded the technology scope and enabled us to observe the changes in the surroundings in distinct ways. More recently, advanced carbon nanomaterials-based films for sensing application have been extensively growing because of their outstanding properties. Based on nanomaterials distinctive structure, enhanced material strength can be obtained in addition to the added multifunctionality of these materials. Such remarkable feature is a main factor in the design of sensors composed of functional nanomaterial. At present carbon nanomaterials, particularly graphene is promising choice for the sensor development due to its unique thermal, electrical and mechanical strength. Therefore, this paper critically discussed on brief history, graphene synthesis, properties, structure, derivatives, graphene based nanocomposites and strain sensor application of graphene based nanomaterials

Magnetic nanoadsorbents' potential route for heavy metals removal - a review

Due to the rapid growth in the heavy metal-based industries, their effluent and local dumping have created significant environmental issues. In the past, typically, removal of heavy metals was handled by reverse osmosis and ion exchange techniques, but these methods have many disadvantages. Therefore, extensive work into the development of improved techniques has increased, especially for heavy metal removal. Many countries are currently researching new materials and techniques based on nanotechnology for various applications that involve extracting heavy metals from different water sources such as wastewater, groundwater, drinking water and surface water. Nanotechnology provides the possibility of enhancing existing techniques to tackle problems more efficiently. The development in nanotechnology has led to the discovery of many new materials such as magnetic nanoparticles. These nanoparticles demonstrate excellent properties such as surface-volume ratio, higher surface area, low toxicity and easy separation. Besides, magnetic nanoparticles can be easily and efficiently recovered after adsorption compared with other typical adsorbents. This review mainly emphasises on the efficiency of heavy metal removal using magnetic nanoadsorbent from aqueous solution. In addition, an in-depth analysis of the synthesis, characterisation and modification approaches of magnetic nanoparticles is systematically presented. Furthermore, future opportunities and challenges of using magnetic particles as an adsorbent for the removal of heavy metals are also discussed

Removal of methylene blue and orange-g from waste water using magnetic biochar

The study on the removal of methylene blue (MB) and orange-G dyes using magnetic biochar derived from the empty fruit bunch (EFB) was carried out. Process parameters such as pH, adsorbent dosage, agitation speed and contact time were optimized using Design-Expert Software v.6.0.8. The statistical analysis reveals that the optimum conditions for the maximum adsorption of MB are at pH 2 and pH 10, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. While for orange-G, at pH 2, dosage 1.0 g, and agitation speed and contact time of 125 rpm and 120 min respectively. The maximum adsorption capacity of 31.25 mg/g and 32.36 mg/g for MB and orange-G respectively. The adsorption kinetic for both dyes obeyed pseudo-second order

Treatment of Industrial Wastewater in a Floating Treatment Wetland: A Case Study of Sialkot Tannery

The city of Sialkot in Pakistan is a hub of leather tanneries, with approximately 260 tanneries in operation and, while producing millions of leather products per day, the city discharges millions of gallons of untreated effluent into drains each day. In order to devise a cost-effective system for the treatment of tannery wastewater, a floating treatment wetland (FTW) was established to treat the effluent using local plant species through phytoremediation. The efficiency of the FTW was tested with three different plant species, each grown separately and operating for three months in the FTW tank. Two of the plant species introduced, water hyacinth and water lettuce, were floating and vascular; the third plant species Typha latifolia was vegetated on a floating mat of styrofoam while the roots extended down to the contaminated water. Wastewater from a tannery drain was pumped into the FTW tank with a flow of 0.5 L per minute and was given a retention time of six days. The influent and effluent from the FTW were periodically tested to determine the percentage removal of contaminants, primarily the total suspended solids, biochemical oxygen demand, chemical oxygen demand, and chromium. After two months with each species, a significant change in the quality of wastewater was measured: chromium was removed by up to 95 percent by the water hyacinth and water lettuce and 33 percent by the Typha latifolia. The pilot model indicates that FTWs are an effective system to treat effluent from tanneries in a cost-effective way as an alternative to establishing an expensive treatment system with high associated operational costs. It can help in achieving the circular economy concept of conventional wastewater schemes towards more sustainable ones. Moreover, to achieve the principles of circular economy and environmentally friendly development, it is crucial that the substances used for a wetland foundation have the capacity to be recycled, are available at a cheap price, and are locally available