Low Overpotential Amperometric Sensor Using Yb2O3.CuO@rGO Nanocomposite for Sensitive Detection of Ascorbic Acid in Real Samples.

The ultimate objective of this research work is to design a sensitive and selective electrochemical sensor for the efficient detection of ascorbic acid (AA), a vital antioxidant found in blood serum that may serve as a biomarker for oxidative stress. To achieve this, we utilized a novel Yb2O3.CuO@rGO nanocomposite (NC) as the active material to modify the glassy carbon working electrode (GCE). The structural properties and morphological characteristics of the Yb2O3.CuO@rGO NC were investigated using various techniques to ensure their suitability for the sensor. The resulting sensor electrode was able to detect a broad range of AA concentrations (0.5-1571 µM) in neutral phosphate buffer solution, with a high sensitivity of 0.4341 µAµM-1cm-2 and a reasonable detection limit of 0.062 µM. The sensor's great sensitivity and selectivity allowed it to accurately determine the levels of AA in human blood serum and commercial vitamin C tablets. It demonstrated high levels of reproducibility, repeatability, and stability, making it a reliable and robust sensor for the measurement of AA at low overpotential. Overall, the Yb2O3.CuO@rGO/GCE sensor showed great potential in detecting AA from real samples.

Rapid elimination of antibiotic gemifloxacin mesylate and methylene blue over Pt nanoparticles dispersed chitosan/g-C3N4 ternary visible light photocatalyst.

Appropriate material selection and proper understanding of bandgap modification are key factors for the development of efficient photocatalysts. Herein, we developed an efficient, well-organized visible light oriented photocatalyst based on g-C3N4 in association with polymeric network of chitosan (CTSN) and platinum (Pt) nanoparticles utilizing a straightforward chemical approach. Modern techniques like XRD, XPS, TEM, FESEM, UV-Vis, and FTIR spectroscopy were exploited for characterization of synthesized materials. XRD results confirmed the involvement of α-polymorphic form of CTSN in graphitic carbon nitride. XPS investigation confirmed the establishment of trio photocatalytic structure among Pt, CTSN, and g-C3N4. TEM examination showed that the synthesized g-C3N4 possesses fine fluffy sheets like structure (100 to 500 nm in size) intermingled with a dense layered framework of CTSN with good dispersion of Pt nanoparticles on g-C3N4 and CTSN composite structure. The bandgap energies for g-C3N4, CTSN/g-C3N4, and Pt@ CTSN/g-C3N4 photocatalysts were found to be 2.94, 2.73, and 2.72 eV, respectively. The photodegradation skills of each created structure have been examined on antibiotic gemifloxacin mesylate and methylene blue (MB) dye. The newly developed Pt@CTSN/g-C3N4 ternary photocatalyst was found to be efficacious for the elimination of gemifloxacin mesylate (93.3%) in 25 min and MB (95.2%) just in 18 min under visible light. Designed Pt@CTSN/g-C3N4 ternary photocatalytic framework exhibited ⁓ 2.20 times more effective than bare g-C3N4 for the destruction of antibiotic drug. This study provides a simple route towards the designing of rapid, effective visible light oriented photocatalyts for the existing environmental issues.

A Sensitive Hydroquinone Amperometric Sensor Based on a Novel Palladium Nanoparticle/Porous Silicon/Polypyrrole-Carbon Black Nanocomposite.

Exposure to hydroquinone (HQ) can cause various health hazards and negative impacts on the environment. Therefore, we developed an efficient electrochemical sensor to detect and quantify HQ based on palladium nanoparticles deposited in a porous silicon-polypyrrole-carbon black nanocomposite (Pd@PSi-PPy-C)-fabricated glassy carbon electrode. The structural and morphological characteristics of the newly fabricated Pd@PSi-PPy-C nanocomposite were investigated utilizing FESEM, TEM, EDS, XPS, XRD, and FTIR spectroscopy. The exceptionally higher sensitivity of 3.0156 µAµM-1 cm-2 and a low limit of detection (LOD) of 0.074 µM were achieved for this innovative electrochemical HQ sensor. Applying this novel modified electrode, we could detect wide-ranging HQ (1-450 µM) in neutral pH media. This newly fabricated HQ sensor showed satisfactory outcomes during the real sample investigations. During the analytical investigation, the Pd@PSi-PPy-C/GCE sensor demonstrated excellent reproducibility, repeatability, and stability. Hence, this work can be an effective method in developing a sensitive electrochemical sensor to detect harmful phenol derivatives for the green environment.

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.

Efficient Detection of 2,6-Dinitrophenol with Silver Nanoparticle-Decorated Chitosan/SrSnO3 Nanocomposites by Differential Pulse Voltammetry.

Herein, an ultra-sonication technique followed by a photoreduction technique was implemented to prepare silver nanoparticle-decorated Chitosan/SrSnO3 nanocomposites (Ag-decorated Chitosan/SrSnO3 NCs), and they were successively used as electron-sensing substrates coated on a glassy carbon electrode (GCE) for the development of a 2,6-dinitrophenol (2,6-DNP) efficient electrochemical sensor. The synthesized NCs were characterized in terms of morphology, surface composition, and optical properties using FESEM, TEM, HRTEM, BET, XRD, XPS, FTIR, and UV-vis analysis. Ag-decorated Chitosan/SrSnO3 NC/GCE fabricated with the conducting binder (PEDOT:PSS) was found to analyze 2,6-DNP in a wide detection range (LDR) of 1.5~13.5 µM by applying the differential pulse voltammetry (DPV) approach. The 2,6-DNP sensor parameters, such as sensitivity (54.032 µA µM-1 cm-2), limit of detection (LOD; 0.18 ± 0.01 µM), limit of quantification (LOQ; 0.545 µM) reproducibility, and response time, were found excellent and good results. Additionally, various environmental samples were analyzed and obtained reliable analytical results. Thus, it is the simplest way to develop a sensor probe with newly developed nanocomposite materials for analyzing the carcinogenic contaminants from the environmental effluents by electrochemical approach for the safety of environmental and healthcare fields in a broad scale.

Sensitive Electrochemical Detection of 4-Nitrophenol with PEDOT:PSS Modified Pt NPs-Embedded PPy-CB@ZnO Nanocomposites.

In this study, a selective 4-nitrophenol (4-NP) sensor was developed onto a glassy carbon electrode (GCE) as an electron-sensing substrate, which decorated with sol-gel, prepared Pt nanoparticles- (NPs) embedded polypyrole-carbon black (PPy-CB)/ZnO nanocomposites (NCs) using differential pulse voltammetry. Characterizations of the NCs were performed using Field Emission Scanning Electron Microscopy (FESEM), Energy-Dispersive Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), Ultraviolet-visible Spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FTIR), High Resolution Transmission Electron Microscopy (HRTEM), and X-ray Diffraction Analysis (XRD). The GCE modified by conducting coating binders [poly(3,4-ethylenedioxythiophene) polystyrene sulfonate; PEDOT:PSS] based on Pt NPs/PPy-CB/ZnO NCs functioned as the working electrode and showed selectivity toward 4-NP in a phosphate buffer medium at pH 7.0. Our analysis of 4-NP showed the linearity from 1.5 to 40.5 µM, which was identified as the linear detection range (LDR). A current versus concentration plot was formed and showed a regression co-efficient R2 of 0.9917, which can be expressed by ip(µA) = 0.2493C(µM) + 15.694. The 4-NP sensor sensitivity was calculated using the slope of the LDR, considering the surface area of the GCE (0.0316 cm2). The sensitivity was calculated as 7.8892 µAµM-1cm-2. The LOD (limit of detection) of the 4-NP was calculated as 1.25 ± 0.06 µM, which was calculated from 3xSD/σ (SD: Standard deviation of blank response; σ: Slope of the calibration curve). Limit of quantification (LOQ) is also calculated as 3.79 µM from LOQ = 10xLOD/3.3. Sensor parameters such as reproducibility, response time, and analyzing stability were outstanding. Therefore, this novel approach can be broadly used to safely fabricate selective 4-NP sensors based on nanoparticle-decorated nanocomposite materials in environmental measurement.

Ag nanoparticle-decorated chitosan/SrSnO3 nanocomposite for ultrafast elimination of antibiotic linezolid and methylene blue.

Effective design of ultrafast new-generation photocatalysts is a challenging task that requires highly dedicated efforts. This research focused on the development and design of ultrafast smart ternary photocatalysts containing SrSnO3 nanostructures in conjugation with chitosan (CTSN) and silver (Ag) nanoparticles by a very simple and straightforward methodology. Modern analytical tools such as FESEM, TEM, XRD, XPS, FTIR, and UV-Vis spectroscopy were employed to characterize the synthesized nanostructures. XRD and XPS analysis confirmed the successful creation of ternary organization among the Ag, CTSN, and SrSnO3. The TEM images clearly confirmed that CTSN possessed overlapping micron-sized sheets with a layered morphology, whereas the undoped SrSnO3 particles exhibited spherical and elongated shapes and particle sizes ranging from 20 to 80 nm. These particles were produced in high density with homogeneously distributed Ag nanoparticles (4-15 nm). The bandgap energy (Eg) for bare SrSnO3, CTSN/SrSnO3, and Ag@CTSN/SrSnO3 nanocomposites was found to be 4.0, 3.94, and 3.7 eV, respectively. The photocatalytic efficiencies of all newly created photocatalysts were evaluated by considering an antibiotic linezolid drug and methylene blue (MB) dye molecule as target analytes. Among all investigated samples, the Ag@CTSN/SrSnO3 photocatalyst was found to be highly superior, with ultrafast removal of the linezolid drug at 96.02% within 25 min and almost total removal of the MB dye in just 12 min under UV light irradiation. The Ag@CTSN/SrSnO3 photocatalyst exhibited removal rate that was 3.36 times faster than that of bare SrSnO3. The present report delivers a highly promising, extremely efficient, and very simple, straightforward treatment methodology for the effective destruction of lethal and notorious pollutants, enabling the appropriate management of current environmental concerns.

Au nanoparticles decorated polypyrrole-carbon black/g-C3N4 nanocomposite as ultrafast and efficient visible light photocatalyst.

Modification and bandgap engineering are proposed to be extremely significant in improving the photocatalytic activity of novel photocatalysts. The current research focused on the fabrication of ultrafast and efficient visible light-responsive ternary photocatalyst containing g-C3N4 nanostructures in conjugation with polypyrrole doped carbon black (PPy-C) and gold (Au) nanoparticles by highly effectual, simple, and straightforward methodology. Various analytical techniques like XRD, FESEM, TEM, XPS, FTIR, and UV-Vis spectroscopy were applied for characterization purposes. The XRD and XPS results confirmed the successful creation of a nanocomposite framework among Au, PPy-C and g-C3N4. The TEM images revealed that bare g-C3N4 holds sheets or layered graphitic structure with sizes ranging from 100 to 300 nm. The sponge-like PPy-C network intermingled perfectly with g-C3N4 sheets along with homogeneously distributed 5-15 nm Au nanoparticles. The band gap energy (Eg) for bare g-C3N4, PPy-C/g-C3N4 and Au@PPy-C/g-C3N4 nanocomposites were found to be 2.74, 2.68, and 2.60 eV, respectively. The photocatalytic activity for all newly designed photocatalysts have been assessed during the degradation of insecticide Imidacloprid and methylene blue (MB) dye, where Au@PPy-C/C3N4 was found to be extremely efficient with ultrafast removal of both imidacloprid and MB in just 25 min of visible light irradiation. It was revealed that the Au@PPy-C/g-C3N4 ternary photocatalyst removed 96.0% of target analyte imidacloprid, which is ⁓ 2.91 times more efficient than bare g-C3N4 in treating imidacloprid. This report provides a distinctly promising, highly effectual and straightforward route to destruct extremely toxic and notorious pollutants and opens a new gateway in the present challenging scenario of environmental concerns.

Development of Methanol Sensor Based on Sol-Gel Drop-Coating Co3O4·CdO·ZnO Nanoparticles Modified Gold-Coated µ-Chip by Electro-Oxidation Process.

Herein, novel Co3O4·CdO·ZnO-based tri-metallic oxide nanoparticles (CCZ) were synthesized by a simple solution method in basic phase. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope (FESEM), Dynamic Light Scattering (DLS), Tunneling Electron Microscopy (TEM), and Energy-Dispersive Spectroscopy (EDS) techniques to characterize the CCZ nanoparticles. XRD, TEM, DLS, and FESEM investigations have confirmed the tri-metallic nanoparticles' structure, while XPS and EDS analyses have shown the elemental compositions of the CCZ nanoparticles. Later, a Au/µ-Chip was modified with the CCZ nanoparticles using a conducting binder, PEDOT: PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in a sol-gel system, and dried completely in air. Then, the CCZ/Au/µ-Chip sensor was used to detect methanol (MeOH) in phosphate buffer solution (PBS). Outstanding sensing performance was achieved for the CCZ/Au/µ-Chip sensor, such as excellent sensitivity (1.3842 µAµM-1cm-2), a wide linear dynamic range of 1.0 nM-2.0 mM (R2 = 0.9992), an ultra-low detection limit (32.8 ± 0.1 pM at S/N = 3), a fast response time (~11 s), and excellent reproducibility and repeatability. This CCZ/Au/µ-Chip sensor was further applied with appropriate quantification results in real environmental sample analyses.

Knowledge, attitude and practices (KAP) towards Anthrax among livestock farmers in selected rural areas of Bangladesh.

BACKGROUND: Bacillus anthracis is a zoonotic bacterium that affects wide numbers of vertebrate animals and man and has life threating potential both in animal s as well as humans. METHODS: A cross sectional study was conducted to assess the knowledge about, attitudes towards, and practices addressing (KAPs) anthrax among community members in selected upazillas' of Meherpur and Sirajgonj districts for the prevention and control of anthrax using a structured questionnaire. RESULTS: A total of 424 community members were considered in this study irrespective of their age and sex. Most of the respondents were female (57.54%) and about half were illiterate (47.40%). Most of the respondents (86.32%) were self-employed with crop and livestock farming. Among the self-employed farmers, cattle (63.73%) were the highest reared animals. Among the respondents, 37.26% had no knowledge about anthrax. On the other hand, among the existing knowledge level, 46.69% received information of anthrax from neighbour, 74.05% and 56.82% were concerned about the mode of transmission of anthrax from animal to human through eating, handling and soil. Respondents usually collected vaccine from quack (58.25%) and vaccination status was highest in Kamarkhand (52.03%) and lowest in Gangni upazilla (10.82%). Overall 62.74% community members considered that anthrax is a fatal disease for livestock and 82.54% people disposed carcass in buried method. CONCLUSION: The study findings indicated that the community members had average knowledge on cause, symptoms, transmission and prevention of anthrax. The supplied vaccine was found negligible with the number of livestock in the studied upazilas. Veterinary and Medical health planners should design and implement interventions for awareness building on anthrax under One Health (OH) approach for educating the community people on anthrax control and prevention.

A Lamin-Associated Chromatin Model for Chromosome Organization.

We propose a simple model for chromatin organization based on the interaction of the chromatin fibers with lamin proteins along the nuclear membrane. Lamin proteins are known to be a major factor that influences chromatin organization and hence gene expression in the cells. We provide a quantitative understanding of lamin-associated chromatin organization in a crowded macromolecular environment by systematically varying the heteropolymer segment distribution and the strength of the lamin-chromatin attractive interaction. Our minimal polymer model reproduces the formation of lamin-associated-domains and provides an in silico tool for quantifying domain length distributions for different distributions of heteropolymer segments. We show that a Gaussian distribution of heteropolymer segments, coupled with strong lamin-chromatin interactions, can qualitatively reproduce observed length distributions of lamin-associated-domains. Further, lamin-mediated interaction can enhance the formation of chromosome territories as well as the organization of chromatin into tightly packed heterochromatin and the loosely packed gene-rich euchromatin regions.

Electrocatalytic Oxidation of 4-Aminophenol Molecules at the Surface of an FeS2 /Carbon Nanotube Modified Glassy Carbon Electrode in Aqueous Medium.

FeS2 /carbon nanotube (CNT) nanocomposites were synthesized and immobilized on the surface of a glassy carbon electrode (GCE) in order to investigate the electrocatalytic conversion of 4-aminophenol (4-AP) into p-quinone in an aqueous medium. The reformed electronic properties (in terms of lowering of band-gap energy and charge-transfer resistance), as well as improved surface area, result in an enhanced redox reaction of 4-AP in the presence of FeS2 -CNT NCs compared to that with FeS2 alone. The 4-AP molecules undergo coupled two-proton and two-electron transfer quasi-reversible redox reactions with a symmetry factor of 0.55 and standard rate constant (k°) of 0.8 cm s-1 . Here, quinone imine is generated as an intermediate which is later converted into quinone in an irreversible hydrolysis reaction. The best catalytic performance can be obtained at the pH value of 7.0.

Enhanced photocatalytic activity and ultra-sensitive benzaldehyde sensing performance of a SnO2·ZnO·TiO2 nanomaterial.

The synthesis of a ternary SnO2·ZnO·TiO2 nanomaterial (NM) by a simple co-precipitation method and its potential applications as an efficient photocatalyst and chemical sensor have been reported. The synthesized nanomaterial was fully characterized by XRD, SEM, EDS, XPS, FTIR, AFM and photoluminescence studies. This nanomaterial exhibited enhanced efficiency in photo-catalysis of Methyl Violet 6b (MV) dye degradation. The observed photocatalyst efficiency of the SnO2·ZnO·TiO2 nanomaterial was 100% under UV light at pH 9. Moreover, it lost around 12% efficiency over five reuses. The PL properties with changing excitation energy were also reported. Glassy carbon electrode (GCE) was modified with the SnO2·ZnO·TiO2 nanomaterial by an efficient electrochemical technique to develop a chemical sensor for selective benzaldehyde. Hazardous benzaldehyde was carefully chosen as a target analyte by a selectivity study; it displays a rapid response towards the SnO2·ZnO·TiO2/Nafion/GCE sensor probe in electrochemical sensing. It also shows superb sensitivity, an ultra-low detection limit, long-term stability, and very good repeatability and reproducibility. In this study, a linear calibration plot was obtained for 0.1 nM to 1.0 mM aqueous benzaldehyde solutions, with a sensitivity value of 4.35 nA µM-1 cm-2 and an exceptionally low detection limit (LOD) of 3.2 ± 0.1 pM (S/N = 3). Hence, a chemical sensor modified with SnO2·ZnO·TiO2/GCE may be a promising sensor in the determination of toxic chemicals in the environmental and healthcare fields.

Thiourea sensor development based on hydrothermally prepared CMO nanoparticles for environmental safety.

Low-dimensional cobalt oxide codoped manganese oxide nanoparticles (CMO NPs; dia. ~ 25.6nm) were synthesized using the hydrothermal method in alkaline phase. The optical, morphological, and structural properties of CMO NPs were characterized in details using FT-IR, UV/vis., FESEM, XEDS, XPS, TEM, and XRD techniques. Glassy carbon electrode (GCE) was fabricated with a thin-layer of CMO NPs by conducting coating binders for the development of selective and sensitive thiourea (TU) sensors. Electrochemical responses along with higher sensitivity, large-dynamic-range, and long-term stability towards TU were performed by electrochemical I-V approach. The calibration curve was found linear over a wide linear dynamic range (LDR) of TU concentration. From the gradient of the calibration plot, limit of detection (LOD), and sensitivity were calculated as 12.0±0.05pM and 3.3772nAnM-1cm-2 respectively. It is an organized route for the development of chemical sensor based on very low-dimensional CMO NPs/GCE using electrochemical reduction phenomena. As far as we know, this report is the maiden publication on highly sensitive TU sensor based on the CMO NPs/GCE. This method could be a pioneer developer in TU sensitive chemical sensor development using doped NPs in the simple I-V method for the important sensor applications with useful doped materials coupled nano-technological systems for environmental safety.

Cd-doped Sb2O4 nanostructures modified glassy carbon electrode for efficient detection of melamine by electrochemical approach.

Cadmium doped antimony oxide (Cd-doped Sb2O4) nanostructures (CAO-NSs) were synthesized by a facile hydrothermal method in alkaline phase at low temperature to detect the melamine from aqueous solution. The calcined CAO-NSs were characterized systematically by FE-SEM, EDS, UV/Vis., FTIR spectroscopy, powder XRD, and XPS techniques. The glassy carbon electrode (GCE) was modified with the CAO-NSs and sensing performance towards the selective melamine was explored by the electrochemical approach in phosphate buffer solution. The melamine undergoes a reduction reaction in the presence of CAO-NSs/GCE in PBS. The CAO-NSs/GCE attained the higher sensitivity (3.153µAµM-1cm-2) for a wide ranges of concentration (LDR: 0.05nM-0.5mM), an ultra-low limit of detection (LOD: 14.0 ± 0.05p.M.; S/N = 3), long-term stability, excellent repeatability, and reproducibility. This method might represent an efficient way of sensitive sensor development for the toxic melamine and their derivatives for the safety of biomedical and health care fields in broad scales.

Crossover from rotational to stochastic sandpile universality in the random rotational sandpile model.

In the rotational sandpile model, either the clockwise or the anticlockwise toppling rule is assigned to all the lattice sites. It has all the features of a stochastic sandpile model but belongs to a different universality class than the Manna class. A crossover from rotational to Manna universality class is studied by constructing a random rotational sandpile model and assigning randomly clockwise and anticlockwise rotational toppling rules to the lattice sites. The steady state and the respective critical behavior of the present model are found to have a strong and continuous dependence on the fraction of the lattice sites having the anticlockwise (or clockwise) rotational toppling rule. As the anticlockwise and clockwise toppling rules exist in equal proportions, it is found that the model reproduces critical behavior of the Manna model. It is then further evidence of the existence of the Manna class, in contradiction with some recent observations of the nonexistence of the Manna class.

Invasion of a sticky random solid: self-established potential gradient, phase separation, and criticality.

Invasion of a sticky random solid by an aqueous solution is modeled through a chemical reaction. In this reaction, the solid elements dissolve in the solution and redeposit back on the rough interface. A self-established potential gradient (SEPG) in the binding energy of the solid is developed spontaneously and the system gets phase separated into "hard" and "soft" solids. The solution profile is found drifted slowly into the solid by the SEPG with a constant velocity. The system tunes itself to the percolation threshold in the steady state. In the steady state, the system is found consisting of finite clusters of solution molecules followed by a path of redeposited solid as an invasion percolation cluster. A diffusive growth of the interface and the solution inside the solid is found to occur. The nonequilibrium steady state of this dynamical system is found critical and characterized by a power-law distribution of cluster size with an exponent approximately -2 .