Superior Non-Invasive Glucose Sensor Using Bimetallic CuNi Nanospecies Coated Mesoporous Carbon

The assessment of blood glucose levels is necessary for the diagnosis and management of diabetes. The accurate quantification of serum or plasma glucose relies on enzymatic and nonenzymatic methods utilizing electrochemical biosensors. Current research efforts are focused on enhancing the non-invasive detection of glucose in sweat with accuracy, high sensitivity, and stability. In this work, nanostructured mesoporous carbon coupled with glucose oxidase (GO_x) increased the direct electron transfer to the electrode surface. A mixed alloy of CuNi nanoparticle-coated mesoporous carbon (CuNi-MC) was synthesized using a hydrothermal process followed by annealing at 700 °C under the flow of argon gas. The prepared catalyst's crystal structure and morphology were explored using X-ray diffraction and high-resolution transmission electron microscopy. The electrocatalytic activity of the as-prepared catalyst was investigated using cyclic voltammetry (CV) and amperometry. The findings show an excellent response time of 4 s and linear range detection from 0.005 to 0.45 mM with a high electrode sensitivity of 11.7 ± 0.061 mA mM cm^-2 in a selective medium.

Hydrophilic Antireflection and Antidust Silica Coatings

We report on the optical and morphological properties of silica thin layers deposited by reactive RF magnetron sputtering of a SiO2 target under different oxygen to total flow ratios [r(O2) = O2/Ar, ranging from 0 to 25%]. The refractive index (n), extinction coefficient, total transmission, and total reflectance were systematically investigated, while field-emission scanning electron microscopy, atomic force microscopy, and three-dimensional (3D) average roughness data construction measurements were carried out to probe the surface morphology. Contact angle measurements were performed to assess the hydrophilicity of our coatings as a function of the oxygen content. We performed a thorough numerical analysis using 1D-solar cell capacitance simulator (SCAPS-1D) based on the measured experimental optical properties to simulate the photovoltaic (PV) device performance, where a clear improvement in the photoconversion efficiency from 25 to 26.5% was clearly observed with respect to r(O2). Finally, a computational analysis using OptiLayer confirmed a minimum total reflectance of less than 0.4% by coupling a silica layer with n = 1.415 with another high-refractive-index (i.e., >2) oxide layer. These promising results pave the way for optimization of silica thin films as efficient antireflection and self-cleaning coatings to display better PV performance in a variety of locations including a desert environment.

Synthesis and analysis of silver–copper alloy nanoparticles of different ratios manifest anticancer activity in breast cancer cells

Background

Breast cancer is therapeutically very challenging to treat as it has the main four known genetic alterations, which result in the existence of several phenotypes leading to the difference in the mode of therapy and with poor outcome. Metallic nanoparticles of silver or copper have been studied previously as anticancer agents in breast cancer and other types of cancers. However, the anticancer effect of silver–copper alloy nanoparticles (AgCu-NP) is not studied in breast cancer. In this study, we aim to synthesize silver nanoparticles (Ag-NP), or copper nanoparticles (Cu-NP), and AgCu-NP and evaluate their toxicity in breast cancer and healthy breast cells.

Results

We synthesized sodium citrate and mercapto-propionic acid (MPA-3) capped water-soluble metallic nanoparticles of Ag-NP or Cu-NP and an alloy of three different combinations of AgCu-NP. High-resolution transmission electron microscopy characterization of nanoparticles revealed the spherical shape nanoparticles of varied sizes, furthermore dynamic light scattering characterization was performed, which investigated the hydrodynamic size and stability in phosphate buffer solution. Energy-dispersive X-ray spectroscopy (EDS) measurements were obtained from the transmission electron microscope to study the composition of alloy nanoparticles and the distribution pattern of silver and copper in the alloy nanoparticles. We measured the toxicity of nanoparticles to breast cancer MCF-7 cell line by MTT assay and compared the toxic effect with non-cancerous breast epithelial cells MCF-10A. Our data showed that Ag-NP or Cu-NP have no effect on cancer cells or healthy cells, except Ag-NP at 20 µg/ml were toxic to cancer cells. However, AgCu-NP were significantly toxic to MCF-7 cells at 10 µg/ml concentration, while as AgCu-NP have no toxic effect on healthy cells. Furthermore, we observed the cell death pathway by the apoptosis marker Annexin-V which showed non-significant results, while the exposure of AgCu-NP in MCF-7 cells leads to toxicity and also caused significant increase in MMP-9 level, which suggests the cell death may be associated with other pathways such as autophagy and oxidative stress related.

Conclusion

The data suggest that the AgCu-NP alloy imposes preferential toxicity in breast cancer MCF-7 cells and thus could be exploited as a new candidate for further anticancer investigation

Oxidation of Au/Ag films by oxygen plasma: phase separation and generation of nanoporosity

The oxidation of Au/Ag alloy thin films using radio-frequency oxygen plasma was studied in this work. It was demonstrated that there is a phase separation occurring between silver and gold. In addition, it was shown that the preferential oxidation of silver resulted in a solid-state diffusion of silver toward the surface where it oxidized and formed nanoporous microspheres. The gold phase remaining in the film exhibited nanoporosity due to the injected vacancies at the metal/silver oxide interface. Based on the scanning transmission electron microscopy analysis coupled with energy dispersive X-ray mapping a mechanism was proposed based on solid-state diffusion and the Kirkendall effect to explain the different steps occurring during the oxidation process.

Functional and prognostic relevance of -173 G/C gene polymorphism of macrophage migration inhibitory factor in sepsis patients in Egyptian intensive care units

This study aimed to evaluate the association of plasma MIF level and -173 G/C single nucleotide polymorphism of the MIF gene with the occurrence, severity and mortality of sepsis patients. A study was conducted in adult surgical intensive care units of Zagazig University Hospitals, Egypt on 25 patients with sepsis, 27 with severe sepsis and 28 controls. Gram-negative bacilli were the most common isolates in both severe sepsis (63.0%) and sepsis (56.0%) patients. A highly statistically significant difference was found in MIF levels between sepsis cases and controls and a statistically significant difference as regards MIF level in different genotypes of the studied groups. MIF level was significantly associated with mortality in sepsis cases. High MIF levels and MIF -173G/C gene polymorphism are powerful predictors of the severity of sepsis and its outcome.

Epidemiological characterization of P. aeruginosa isolates of intensive care units in Egypt and Saudi Arabia

This study aimed to characterize Pseudomonas aeruginosa isolates in 2 intensive care units in Egypt and Saudi Arabia. P. aeruginosa isolates from patients' and staff hands and environmental samples were typed using antibiotyping and ERIC-PCR. In Egypt, isolates from suction apparatus tubing and drainage containers (A7) and AV tubing (A8) were linked to those from patients who had these antibiotypes. In Saudi Arabia, isolates from suction apparatus tubing (A6) and AV tubing (A7) were linked to patients with the same antibiotypes. In Egypt, patients' isolates had ERIC VII, VIll and IX patterns linked to suction apparatus tubing, AV machine tubes and drainage containers. In Saudi Arabia, patients' isolates had ERIC VIII and XI patterns linked to suction apparatus tubing and AV machines. In Egypt and Saudi Arabia, ERIC typing gave higher discriminatory indices (0.801 and 0.785 respectively) than the antibiotyping (0.7123 and 0.728 respectively). ERIC was superior to antibiotyping and should be used in tracing sources of infection.

Adverse effects of lactational exposure to chlorpyrifos in suckling rats

The present study was undertaken to evaluate the oxidative damage, biochemical and histopathological alterations in sucking rats whose mothers were exposed to the insecticide chlorpyrifos (CPF). Dams were administered CPF, via oral route. Doses equalled 0.01 mg kg(-1) body weight (b.wt.; acceptable daily intake, ADI), 1.00 mg kg(-1) b.wt. (no observed adverse effects level, NOAEL) and 1.35 mg kg(-1) b.wt. (1/100 lethal dose [LD(50)]) from postnatal day 1 until day 20 after delivery. At two high doses of CPF, the body weight gain and relative liver and kidney weight of suckling pups were significantly decreased. Exposure of the mothers to CPF caused increase in lipid peroxidation (LPO) and decrease in superoxide dismutase (SOD) and glutathione-s-transferase (GST) in lactating pups. CPF altered the level of the marker parameters related to the liver and kidneys. Consistent histological changes were found in the liver and kidneys of the subjected pups, especially at the higher doses. The results suggested that the transfer of CPF intoxication through the mother's milk has resulted in oxidative stress and biochemical and histopathological alterations in the suckling pups. The data of this study may be considered as a contribution to the problem of lactational transfer of the relatively less persistent OP pesticides, such as CPF.

Botanical biocides. 4. Mosquitocidal activity of certain Thymus capitatus constituents

Successive extraction of Thyme plant, Thymus capitatus (L.) Hoffm. and Link (Lamiaceae), by different solvents of increasing polarity, showed that potency was highly attributed to the non-polar fraction (e.g., petroleum ether) when tests were carried out against the larvae and adults of Culex pipiens (L). Of special concern to the mosquitocidal activity, the following fractions and isolates were recognized: the volatile oil, unsaponifiable portion, and certain compounds isolated from the unsaponifiable portion (e.g., Thymol, alpha-Amyrin, Carvacrol + beta-Caryophyllene). The volatile oil, Thymol, and the unsaponifiable portion proved high larvicidal potency against the tested insect (LC50 = 49.0, 58.0, and 100.0 ppm, respectively). Non-lethal concentrations of these substances synergized the toxicity of Malathion, while induced additive or antagonistic effects when mixed with Permethrin or Pirimiphos-methyl. The unsaponifiable portion and volatile oil showed the highest adulticidal potency (LC50 = 0.0070 and 0.0076 mg/cm2, respectively). The efficacy of the tested candidates as repellent agents was found in the following order: unsaponifiable portion > alpha-Amyrin > Thymol > volatile oil > Carvacrol + beta-Caryophyllene. Thymol as well as volatile oil affected egg hatchability, causing Sterility Indices accounting for 0.70 and 0.74, respectively, while the unsaponifiable portion showed lower degree of sterility (0.81). The results obtained in this study may shed light on the importance of T. capitatus as a probable source of some biologically active agents for mosquito control in the future.

The importance of detecting circulating Toxoplasma antigens in human cases

This work was performed on 100 suspected toxoplasmosis cases including 75 females with complicated obstetric histories, 15 children presented with hydrocephalus, retino-chorditis and lymphadenitis and 10 children suffering from leukaemia. Also 40 age-matched controls were included in this study. Serum samples from all patients and controls were examined to detect anti-Toxoplasma IgG and IgM using indirect ELISA. Antiserum against Toxoplasma avirulent strain was prepared in New-Zealand white rabbit, then it was used after purification for detecting circulating Toxoplasma antigens in the sera of these studied groups using a double antibody sanwich ELISA technique. Positive anti-Toxoplasms IgG was detected in 45% of the female group while 19% were IgM positive. According to IgM/IgG ratio, 9 cases were considered as acutely infected-females and 25 as chronically infected ones. The mean optical density of both IgG and IgM among acutely and chronically infected females were found significantly higher than of the control groups. Ten non-leukaemic children were IgG and IgM positive cases and were considered as acutely infected patients. On the other hand, all children with leukaemia were negative for anti-Toxoplasma IgG and IgM. Eleven out of 19 acutely infected cases (58%) had positive Toxoplasma antigens, whereas, only one case (4%) with chronic infection had positive antigen level. The mean optical density of circulating antigen level was significantly higher among acutely infected females and children than chronically infected and control groups. No antigen level difference was found between chronically infected patients and control groups. Six children from leukaemic group (60%) had positive circulating Toxoplasma antigen levels with significantly higher mean optical density than control groups (P < 0.001). As a conclusion the results demonstrate that the detection of circulating antigens can aid in the diagnosis of infection by T. gondii in humans, specially in immuno-compromised patients whose serologic response can be impaired.

Third Congress of Toxicology in Developing Countries: Together for Human and Environmental Welfare [meeting report]

Images

The mutagenicity of Gramoxone (paraquat) on different eukaryotic systems

The possible mutagenicity of the herbicide Gramoxone was evaluated using five different living systems: Allium cepa, Vicia faba, yeast, Drosophila melanogaster and human lymphocytes. The results indicate that Gramoxone has mutagenic activity at the cytological level in Allium cepa, Vicia faba and human lymphocytes. All doses were effective in inducing chromosomal abnormalities and a clear dose-response relationship was observed in the various cytological tests. Analysis of chromosomal abnormalities revealed that this herbicide displays clastogenic and turbagenic activities. At the gene mutation level Gramoxone induced gene conversion at the trp-5 locus and reversion at the ilv locus in Saccharomyces cerevisiae. In Drosophila melanogaster, Gramoxone proved to be mutagenic to germ cells and induced a high frequency of sex-linked recessive lethals (SLRL). At the protein level, Gramoxone had detectable mutagenic effects on the genetic background of two enzymes, Adh and Est-6. Gramoxone should be considered a mutagenic herbicide.