Polyphenols-Rich Extract of Calotropis procera Alone and in Combination with Trichoderma Culture Filtrate for Biocontrol of Cantaloupe Wilt and Root Rot Fungi.

Fungal diseases have always been a major problem for cantaloupe crops; however, synthetic fungicides are hazardous to humans and the environment. Consequently, a feasible alternative to fungicides without side effects could be by using bio agents and naturally occurring plants with antibacterial potential. This study has achieved a novel procedure for managing wilt and root rot diseases by potentially using Trichoderma sp. culture filtrates in consortium with plant extract of Calotropis procera, Rhizoctonia solani, Fusarium oxysporum, and Pythium ultimum, which were isolated from infected cantaloupe roots with identified root rot symptoms. The antagonistic activity of four Trichoderma isolates and analysis of antibiotics and filtrate enzymes of the most active Trichoderma isolate were determined as well as phytochemical analysis of C. procera plant extract using HPLC-UV. The obtained results showed that all Trichoderma isolates considerably lowered the radial growth of P. ultimum, R. solani, and F. oxysporum in varying degrees. The scanning electron micrographs illustrate the mycoparasitic nature of Trichoderma sp. on F. oxysporum. The phytochemical analysis of C. procera indicated that phenolic contents were the major compounds found in extracts, such as vanillin (46.79%), chlorogenic acid (30.24%), gallic acid (8.06%), and daidzein (3.45%) but including only a low amount of the flavonoid compounds rutin, naringenin, and hesperetin. The Pot experiment's findings showed that cantaloupe was best protected against wilting and root rot diseases when it was treated with both Trichoderma sp. culture filtrates (10%) and C. procera extract of (15 mg/mL), both alone and in combination. This study demonstrates that the application of bio agent Trichoderma spp. filtrate with C. procera phenol extract appears useful for controlling wilting and root rot disease in cantaloupe. This innovative approach could be used as an alternative to chemical fungicide for the control of wilting and rot root diseases.

Remarkable Recycling Process of ZnO Quantum Dots for Photodegradation of Reactive Yellow Dye and Solar Photocatalytic Treatment Process of Industrial Wastewater.

The mineralization of five industrial sunlight-exposed wastewater samples was investigated, and the recycling process of ZnO quantum dots (ZQDs) for five reusable times was estimated under the approved Egyptian Environmental Law COD (Chemical Oxygen Demand), which has to be less than 1000 ppm. An improved sol-gel process at a low calcination temperature that ranged between 350 and 450 °C was employed to synthesize ZnO quantum dots (ZQDs). The purity, high crystallinity, and structure of the prepared catalysts were determined by TEM and XRD analysis. The energy bandgap, the crystal size values, and the surface area for Z1 and Z2 were determined based on the TEMs, DRSs, and EBTs, which were equal to 6.9 nm, 3.49 eV, and 160.95 m2/g for Z1 and 8.3 nm, 3.44 eV, and 122.15 m2/g for Z2. The investigation of the prepared samples was carried out by studying the photocatalytic activity and photoluminescence, and it was found that the degradation rate of reactive yellow dye as an industrial pollutant of the Z1 sample was significantly higher than other samples, by 20%. The data collection has shown that photocatalytic efficiency decreases with an increase in the crystallite size of ZQDs.

Recycling for solar photocatalytic activity of Dianix blue dye and real industrial wastewater treatment process by zinc oxide quantum dots synthesized by solvothermal method.

Solar photocatalytic activity of zinc oxide quantum dots (ZOQDs) was investigated and two samples of ZOQDs were synthesized by solvothermal method and characterized using different spectroscopic techniques. Crystal and morphological properties were obtained from XRD and HRTEM showed the purity, high crystallinity single phase and the elongated shape of prepared quantum dots. The measured crystallite size of the S1 and S2 samples is 8.4 and 9.6 nm respectively. The results of BET analysis and the optical properties of the samples shown that the first sample have larger values for both the specific surface area and band gap energy. Estimation of the photocatalytic performance indicated that the first sample give the best degradation rate of the synthetic Dianix Blue dye (DB) dye (2.47 × 10-2 s-1). Likewise, in the photo-oxidation of coumarin, the sample with the smallest particle size achieves the highest by 20% fluorescence rate than the largest particle size sample. In addition, the work included a study of the mineralization and recycling efficiency of industrial wastewater as a study case in the presence of different doses of ZOQDs by sun light for a one year and this evaluation done according to Egyptian allowed COD limit according to local environmental ministry law.

Novel Validated Analytical Method Based on Potentiometric Transduction for the Determination of Citicoline Psychostimulant/Nootropic Agent.

Herein, a novel validated potentiometric method is presented for the first time for citicoline determination. The method is based on measuring the potential using new constructed citicoline electrodes. The electrodes are based on the use of citicolinium/phosphomolybdate [Cit]2[PM] (sensor I) and citicolinium/tetraphenylborate [Cit][TPB] (sensor II) ion association complexes. These sensory materials were dispersed in plasticized polyvinyl chloride (PVC) polymeric membranes. The sensors revealed a Nernstian response with the slopes 55.9 ± 1.8(r2 = 0.9994) and 51.8 ± 0.9 (r2 = 0.9991) mV/decade over a linearity range of 6.3 × 10-6-1.0 × 10-3 and 1.0 × 10-5-1.0 × 10-3 M and detection limits of 3.16 × 10-6 and 7.1 × 10-6 M for sensors I and II, respectively. To ensure the existence of monovalent citicoline, all measurements were performed in 50 mM acetate buffer at pH 3.5. All presented electrodes showed good performance characteristics such as rapid response, good selectivity, high potential-stability and long life-span. Method verification and validation in terms of response linearity, quantification limit, accuracy, bias, trueness, robustness, within-day variability and between-days variability were evaluated. The method was introduced for citicoline determination in different pharmaceutical formulations and compared with the standard high performance liquid chromatography (HPLC) method.

Liquid Contact-Selective Potentiometric Sensor Based on Imprinted Polymeric Beads Towards 17ß-Estradiol Determination.

Novel potentiometric devices "ion-selective electrodes (ISEs)" were designed and characterized for the detection of 17ß-estradiol (EST) hormone. The selective membranes were based on the use of man-tailored biomimics (i.e., molecularly imprinted polymers (MIPs)) as recognition ionophores. The synthesized MIPs include a functional monomer (methacrylic acid (MAA)) and a cross-linker (ethylene glycol dimethacrylic acid (EGDMA)) in their preparation. Changes in the membrane potential induced by the dissociated 17ß-estradiol were investigated in 50 mM CO32-/HCO3- buffer solution at pH 10.5. The ion-selective electrodes (ISEs) exhibited fast response and good sensitivity towards 17ß-estradiol with a limit of detection 1.5 µM over a linear range starts from 2.5 µM with an anionic response of 61.2 ± 1.2 mV/decade. The selectivity pattern of the proposed ISEs was also evaluated and revealed an enhanced selectivity towards EST over several phenolic compounds. Advantages revealed by the presented sensor (i.e., wide range of assay, enhanced accuracy and precision, low limit of detection, good selectivity, long-term potential stability, rapid response and long life-span and absence of any sample pretreatment steps) suggest its use in routine quality control/quality assurance tests. They were successfully applied to estradiol determination in biological fluids and in different pharmaceutical preparations collected from the local market.

Validation of a Novel Potentiometric Method Based on a Polymeric PVC Membrane Sensor Integrated with Tailored Receptors for the Antileukemia Drug Cytarabine.

A simple, rapid and easy method is proposed for the detection of a cytostatic therapeutic drug, cytarabine, in real samples. The method is based on potentiometric transduction using prepared and characterized new ion-selective electrodes for cytarabine. The electrodes were integrated with novel man-tailored imprinted polymers and used as a sensory element for recognition. The electrodes revealed a remarkable potentiometric response for cytarabine over the linearity range 1.0 × 10-6-1.0 × 10-3 M at pH 2.8-4 with a detection limit of 5.5 × 10-7 M. The potentiometric response was near-Nernstian, with average slopes of 52.3 ± 1.2 mV/decade. The effect of lipophilic salts and plasticizer types on the potentiometric response was also examined. The electrodes exhibited an enhanced selectivity towards cytarabine over various foreign common ions. Validation and verification of the presented assay method are demonstrated by evaluating the method ruggedness and calculating the detection limit, range of linearity, accuracy (trueness), precision, repeatability (within-day) and reproducibility (between-days). The proposed ion-selective electrodes revealed good performance characteristics and possible application of these electrodes for cytarabine monitoring in different matrices. The electrodes are successfully applied to cytarabine determination in spiked biological fluid samples and in pharmaceutical formulations.

Solid-Contact Potentiometric Sensors Based on Stimulus-Responsive Imprinted Polymers for Reversible Detection of Neutral Dopamine.

Herein, we present for the first time a novel potentiometric sensor based on the stimulus-responsive molecularly imprinted polymer (MIP) as a selective receptor for neutral dopamine determination. This smart receptor can change its capabilities to recognize according to external environmental stimuli. Therefore, MIP-binding sites can be regenerated in the polymeric membrane by stimulating with stimulus after each measurement. Based on this effect, reversible detection of the analyte via potentiometric transduction can be achieved. MIPs based on 4-vinylphenylboronic acid as the functional monomer were prepared as the selective receptor. This monomer can successfully bind to dopamine via covalent binding and forming a five- or six-membered cyclic ester in a weakly alkaline aqueous solution. In acidic medium, the produced ester dissociates and regenerates new binding sites in the polymeric membrane. The proposed smart sensor exhibited fast response and good sensitivity towards dopamine with a limit of detection 0.15 µM over the linear range 0.2-10 µM. The selectivity pattern of the proposed ISEs was also evaluated and revealed an enhanced selectivity towards dopamine over several phenolic compounds. Constant-current chronopotentiometry is used for evaluating the short-term potential stability of the proposed ISEs. The obtained results confirm that the stimulus-responsive MIPs provide an attractive way towards reversible MIP-based electrochemical sensors designation.