Clustered regularly interspaced short palindromic repeats cas systems: a comprehensive review

The clustered regularly interspaced short palindromic repeats (CRISPR) system was recently identified as a bacterial defense mechanism against phages and plasmids. The CRISPR system is composed of DNA arrays containing short sequences identical to those present in phages and plasmids. These short DNAs are transcribed and processed by CRISPR associated proteins that also guide other CRISPR proteins to target the invading DNA. Only a few of the CRISPR components have been characterized to date, and their mechanism of action is still largely unknown. Phage defense mechanisms probably have co-evolved against the CRISPR system, but none has yet been found. We propose to identify phage genes that counteract the CRISPR system

Efficient nitrite determination by electrochemical approach in liquid phase with ultrasonically prepared gold-nanoparticle-conjugated conducting polymer nanocomposites

An electrochemical nitrite sensor probe is introduced herein using a modified flat glassy carbon electrode (GCE) and SrTiO3 material doped with spherical-shaped gold nanoparticles (Au-NPs) and polypyrrole carbon (PPyC) at a pH of 7.0 in a phosphate buffer solution. The nanocomposites (NCs) containing Au-NPs, PPyC, and SrTiO3 were synthesized by ultrasonication, and their properties were thoroughly characterized through structural, elemental, optical, and morphological analyses with various conventional spectroscopic methods, such as field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller method. The peak currents due to nitrite oxidation were characterized in detail and analyzed using conventional cyclic voltammetry (CV) as well as differential pulse voltammetry (DPV) under ambient conditions. The sensor response increased significantly from 0.15 to 1.5 mM of nitrite ions, and the sensor was fabricated by coating a conducting agent (PEDOT:PSS) on the GCE to obtain the Au-NPs/PPyC/SrTiO3 NCs/PEDOT:PSS/GCE probe. The sensor’s sensitivity was determined as 0.5 μA/μM∙cm2 from the ratio of the slope of the linear detection range by considering the active surface area (0.0316 cm2) of the flat GCE. In addition, the limit of detection was determined as 20.00 ± 1.00 µM, which was found to be satisfactory. The sensor’s stability, pH optimization, and reliability were also evaluated in these analyses. Overall, the sensor results were found to be satisfactory. Real environmental samples were then analyzed to evaluate the sensor’s reliability through DPV, and the results showed that the proposed novel electrochemical sensor holds great promise for mitigating water contamination in the real samples with the lab-made Au-NPs/PPyC/SrTiO3 NC. Thus, this study provides valuable insights for improving sensors for broad environmental monitoring applications using the electrochemical approach

Development of a Toxic Lead Ionic Sensor Using Carboxyl-Functionalized MWCNTs in Real Water Sample Analyses

Functional multiwall carbon nanotubes (f-MWCNTs) are of significant interest due to their dispersion ability in the aqueous phase and potential application in environmental, nanotechnology, and biological fields. Herein, we functionalized MWCNTs by a simple acid treatment under ultra-sonification, which represented a terminal or side-functional improvement for the fabrication of a toxic lead ion sensor. The f-MWCNTs were characterized in detail by XRD, Raman, XPS, BET, UV/vis, FTIR, and FESEM-coupled XEDS techniques. The analytical performance of the f-MWCNTs was studied for the selective detection of toxic lead ions by inductively coupled plasma-optical emission spectrometry (ICP-OES). The selectivity of the f-MWCNTs was evaluated using several metal ions such as Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Ni2+, Pb2+, and Zn2+ ions. Lastly, the newly designed ionic sensor was successfully employed to selectively detect lead ions in several environmental water samples with reasonable results. This approach introduced a new technique for the selective detection of heavy metal ions using functional carbon nanotubes with ICP-OES for the safety of environmental and healthcare fields on a broad scale

Understanding the impact of bridge structure on river morphology through geospatial techniques: case on Teesta River, Bangladesh

Abstract The primary priority of bridge construction over a waterway is to support and confirm constant communication. Conversely, it may locally disrupt the health of the river which will have an adverse influence on the hydrological as well as morphological behavior of nearby regions by way of the river’s narrowing. The current study evaluated the effect of bridge structure on river morphological characteristics for Teesta River. Hence to do, this work robbed two approaches. Firstly, the Landsat images from a pre-road bridge (2001 and 2006) and post-road bridge construction (2011, 2016, and 2021) are processed and used for bar formation and bank line shifting. Secondly, the bar properties, differences in channel width, and changes in river bank were evaluated using geospatial technology. The outcomes revealed a recurrent change of bar area and channel width at the upstream side of the bridges and likewise dominating at the downstream side. Throughout the post-road bridge period, the average bar area has increased noticeably by 32.45 sq.km which is 7.75% of the total river area and the downstream bar area has also increased considerably. Besides, both bank lines of the river were dominated by erosion in the post-road bridge construction era. Accordingly, the Teesta Road bridge’s existence has had a significant impact on the morphological modification in recent years. The study also reveals that the bars and islands of Teesta River undergo a drastic change and the river can be treated as a braided one, and also showed the minor trend of meandering. The findings of this research may be supportive for sustainable and long-term planning and development of the rivers and neighboring floodplains in Bangladesh

A novel In2O3-doped ZnO decorated mesoporous carbon nanocomposite as a sensitive and selective dopamine electrochemical sensor

Dopamine (DA), a critical biomolecule involved in neurotransmission, is implicated in a variety of neurological disorders. Therefore, accurate detection of DA is crucial for the swift diagnosis of conditions arising from abnormal DA levels. Consequently, we utilized a novel nanocomposite material comprising In2O3-doped ZnO decorated on mesoporous carbon (In2O3·ZnO@MC) as the active nanomaterial for the fabrication of a glassy carbon electrode (GCE). The structural and morphological properties of In2O3·ZnO@MC were comprehensively analyzed utilizing a variety of characterization techniques to confirm its functionality as the sensing nanomaterial. This innovative sensor demonstrates the ability to detect a wide range of DA concentrations, ranging from 0.5 to 2056 μM, in a neutral phosphate buffer solution, exhibiting a high sensitivity of 0.2153 μAμM−1cm−2 and an acceptable detection limit of 0.024 μM. This sensor enables precise DA level measurements in real samples due to its high sensitivity and selectivity. Moreover, it is a dependable and trustworthy sensor for DA measurement due to its outstanding reproducibility, repeatability, and stability

Facile synthesis of platinum/polypyrrole-carbon black/SnS2 nanocomposite for efficient photocatalytic removal of gemifloxacin under visible light

Development and designing of effective visible light photocatalysts to overcome the drastrous situation of water pollution requires material with excellent charge transferring skills. In this regard, an efficient ternary nanocomposite photocatalyst comprised of SnS2 nanostructure linked with polypyrrole-doped carbon black (PPC) and platinum nanoparticles (Pt NPs) was successfully fabricated. Effective ternary photocatalyst was synthesized by hydrothermal technique followed by ultra-sonication and photo-reduction methodologies. The XRD measurements confirmed the hexagonal phase of SnS2, and the proper formation of nanocomposite. TEM examination revealed Pt NPs of 5–15 nm in size, dense cocoon like layered structure of PPC along with irregular pellets of SnS2. Acquired diffuse reflectance data confirmed the visible light band gap of synthesized nanomaterials. The Pt@PPC/SnS2 photocatalyst showed excellent destructive potential under visible light with 92.40 % removal of antibiotic gemifloxacin (GFX) in 30 minutes, almost 347 % more efficient than bare SnS2, and was found to be ultrafast for the removal of methylene blue (MB) with total elimination of dye just in 10 minutes. The photoluminescence and photocurrent transient analysis revealed enhanced light absorption capability and increased photo-induced carrier transfer with effective separation behavior, together with increased effective surface area of the ternary photocatalyst as evidenced by the BET surface area measurement

Au nanoparticles dispersed polypyrrole-carbon black/SrTiO3 nanocomposite photocatalyst with rapid and stable photocatalytic performance

The current chaotic environmental situation especially water pollution prerequisites efficient novel photocatalysts for the proper treatment of these toxic structures through advanced oxidation process. However, the development of active photocatalytic structures requires further committed effort to ensure proper designing and essential band gap. In this report, an attempt has been made to fabricate a rapid and efficient photocatalyst based on SrTiO3 nanostructures, polypyrrole doped carbon black (PPyC) and Au nanoparticles to tackle serious problems of water contamination. Au@PPyC/SrTiO3 ternary photocatalyst was smoothly fabricated by sol gel route followed by ultrasonication and photoreduction technique. X-ray powder diffraction (XRD) studies revealed that SrTiO3 have cubic perovskite structure, while X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) confirmed the formation of ternary framework among Au, PPyC and SrTiO3 nanostructures. Transmission electron microscopy (TEM) revealed that SrTiO3 possessed irregular porous nanoparticles ranging from 10 to 100 nm, whereas the PPyC appeared as well-ordered chain of beads or interconnected branches of nanoparticles. Modification of bare SrTiO3 to Au@PPyC/SrTiO3 significantly increases the surface area to 2.48 times than that of SrTiO3. The photocatalytic performance of the newly developed Au@PPyC/SrTiO3 photocatalyst has been tested on insecticide imidacloprid and on methylene blue (MB) dye. The current Au@PPyC/SrTiO3 photocatalytic framework exhibited ultrafast skills by removing 96.65% of imidacloprid just in 15 min and found to be ∼3.5 times more effective than bare SrTiO3. Besides this Au@PPyC/SrTiO3 photocatalyst was proven to be extremely destructive for resistant MB dye structure

Electrochemical detection of hydroquinone as an environmental contaminant using Ga2O3 incorporated ZnO nanomaterial

The primary objective of this research endeavor is to develop a highly sensitive and selective electrochemical sensor for the accurate detection of hydroquinone (HQ), a prevalent environmental contaminant. To achieve this, we employed a novel nanocomposite consisting of Ga2O3-doped ZnO (Ga2O3.ZnO) as the active nanomaterial for fabricating a glassy carbon electrode (GCE). The structure and morphology of the Ga2O3.ZnO nanocomposite were rigorously analyzed using a diverse range of techniques to ensure its suitability as the sensing nanomaterial. This innovative sensor exhibits remarkable capabilities, enabling the detection of HQ across a broad concentration range, spanning from 1 to 11070 µM, in a neutral phosphate buffer solution. It boasts an exceptionally high sensitivity of 1.0229 µA µM−1 cm−2 and an impressive detection limit of 0.063 µM. Thanks to its exceptional sensitivity and specificity, this sensor can precisely quantify HQ levels in real-world samples. Moreover, its outstanding reproducibility, repeatability, and stability establish it as a dependable and resilient choice for HQ determination