S. B. Abd Hamid

Analysis of pork adulteration in commercial meatballs targeting porcine-specific mitochondrial cytochrome b gene by TaqMan probe real-time polymerase chain reaction

A test for assessing pork adulteration in meatballs, using TaqMan probe real-time polymerase chain reaction, was developed. The assay combined porcine-specific primers and TaqMan probe for the detection of a 109 bp fragment of porcine cytochrome b gene. Specificity test with 10 ng DNA of eleven different species yielded a threshold cycle (Ct) of 15.5 ± 0.20 for the pork and negative results for the others. Analysis of beef meatballs with spiked pork showed the assay can determine 100-0.01% contaminated pork with 102% PCR efficiency, high linear regression (r(2) = 0.994) and ≤ 6% relative errors. Residuals analysis revealed a high precision in all determinations. Random analysis of commercial meatballs from pork, beef, chicken, mutton and goat, yielded a Ct between 15.89 ± 0.16 and 16.37 ± 0.22 from pork meatballs and negative results from the others, showing the suitability of the assay to determine pork in commercial meatballs with a high accuracy and precision.

Electrochemistry and electrocatalysis of cobalt(II) immobilized onto gel-assisted synthesized zinc oxide nanoparticle–multi wall carbon nanotube–polycaprolactone composite film: application to determination of glucose

Nanoparticles of zinc oxide were synthesized by a simple and low-cost method using gelatin as organic precursor. Techniques of X-ray diffraction (XRD) and scanning electron microscope (SEM) were used to characterize the structure and property of the zinc oxide. The results show that the ZnO nanoparticles with high crystallinity can be obtained using this simple method. Gelatin plays an important role in the formation of the ZnO nanoparticles. Moreover, the composite film was prepared by synthesized ZnO nanoparticles, multi wall carbon nanotube (MWNT) and polycaprolactone (PCL) on glassy carbon electrode (ZnO–MWNT–PCL–GCE). The porous ZnO–MWNT–PCL film was used as a supporting matrix to immobilize Co(II) ions. Immobilized Co ions exhibit excellent electrocatalytic activities to glucose oxidation. The sensor responded linearly to glucose in the concentration of 5.0 × 10−5 to 6.0 × 10−3 M with detection limit of 1.6 × 10−5 M at 3σ using cyclic voltammetry (CV). Moreover, the studied biosensor exhibited good reproducibility and long-term stability. Furthermore, the fabricated electrode displayed voltammetry response to the glucose in human blood serum and the results were matched with referenced values obtained by the standard technique.

The porous chitosan–sodium dodecyl sulfate–carbon nanotube nanocomposite: direct electrochemistry and electrocatalysis of hemoglobin

A novel biosensor is developed based on immobilization of hemoglobin (Hb) on chitosan–sodium dodecyl sulfate–carbon nanotube composite modified glassy carbon electrode (Hb/CS–SDS–CNT/GCE). The surface morphologies of the modified electrode were characterized by SEM, and direct electrochemistry of Hb on Hb/CS–SDS–CNT/GCE was investigated by cyclic voltammetry (CV) and electron impedance spectroscopy (EIS). UV-vis spectroscopic results indicated that Hb molecules in the composite film retained the native structure. The results indicate that Hb immobilized on the surface of the modified electrode could keep its bioactivity, exhibiting a surface-controlled electrochemical process. The kinetic parameters for the electrode reaction, such as the formal potential (E°), the electron transfer rate constant (ks), the apparent coverage (Γ), and Michaelis–Menten constant (Km) are evaluated. Moreover, the immobilized Hb also displayed its good electrocatalytic activity for the reduction of hydrogen peroxide with a low detection limit of 4.2 μM and good stability and reproducibility. The results demonstrate that porous CS–SDS–CNT composite can improve the Hb loading with retention of its bioactivity, and greatly promote the direct electron transfer, which can be attributed to its high specific surface area, uniform ordered porous structure, suitable pore size and biocompatibility.

Development of swine-specific DNA markers for biosensor-based halal authentication.

The pig (Sus scrofa) mitochondrial genome was targeted to design short (15-30 nucleotides) DNA markers that would be suitable for biosensor-based hybridization detection of target DNA. Short DNA markers are reported to survive harsh conditions in which longer ones are degraded into smaller fragments. The whole swine mitochondrial-genome was in silico digested with AluI restriction enzyme. Among 66 AluI fragments, five were selected as potential markers because of their convenient lengths, high degree of interspecies polymorphism and intraspecies conservatism. These were confirmed by NCBI blast analysis and ClustalW alignment analysis with 11 different meat-providing animal and fish species. Finally, we integrated a tetramethyl rhodamine-labeled 18-nucleotide AluI fragment into a 3-nm diameter citrate-tannate coated gold nanoparticle to develop a swine-specific hybrid nanobioprobe for the determination of pork adulteration in 2.5-h autoclaved pork-beef binary mixtures. This hybrid probe detected as low as 1% pork in deliberately contaminated autoclaved pork-beef binary mixtures and no cross-species detection was recorded, demonstrating the feasibility of this type of probe for biosensor-based detection of pork adulteration of halal and kosher foods.

Isolation, Characterization, and Identification of Biological Control Agent for Potato Soft Rot in Bangladesh

A total of 91 isolates of probable antagonistic bacteria of potato soft rot bacterium Erwinia carotovora subsp. carotovora (Ecc) were extracted from rhizospheres and endophytes of various crop plants, different soil varieties, and atmospheres in the potato farming areas of Bangladesh. Antibacterial activity of the isolated probable antagonistic bacteria was tested in vitro against the previously identified most common and most virulent soft rot causing bacterial strain Ecc P-138. Only two isolates E-45 and E-65 significantly inhibited the in vitro growth of Ecc P-138. Physiological, biochemical, and carbon source utilization tests identified isolate E-65 as a member of the genus Bacillus and the isolate E-45 as Lactobacillus sp. The stronger antagonistic activity against Ecc P-138 was found in E-65 in vitro screening and storage potatoes. E-65 reduced the soft rot infection to 22-week storage potatoes of different varieties by 32.5–62.5% in model experiment, demonstrating its strong potential to be used as an effective biological control agent for the major pectolytic bacteria Ecc. The highest (62.5%) antagonistic effect of E-65 was observed in the Granola and the lowest (32.7%) of that was found in the Cardinal varieties of the Bangladeshi potatoes. The findings suggest that isolate E-65 could be exploited as a biocontrol agent for potato tubers.

Botanicals to Control Soft Rot Bacteria of Potato

Extracts from eleven different plant species such as jute (Corchorus capsularis L.), cheerota (Swertia chiraita Ham.), chatim (Alstonia scholaris L.), mander (Erythrina variegata), bael (Aegle marmelos L.), marigold (Tagetes erecta), onion (Allium cepa), garlic (Allium sativum L.), neem (Azadiracta indica), lime (Citrus aurantifolia), and turmeric (Curcuma longa L.) were tested for antibacterial activity against potato soft rot bacteria, E. carotovora subsp. carotovora (Ecc) P-138, under in vitro and storage conditions. Previously, Ecc P-138 was identified as the most aggressive soft rot bacterium in Bangladeshi potatoes. Of the 11 different plant extracts, only extracts from dried jute leaves and cheerota significantly inhibited growth of Ecc P-138 in vitro. Finally, both plant extracts were tested to control the soft rot disease of potato tuber under storage conditions. In a 22-week storage condition, the treated potatoes were significantly more protected against the soft rot infection than those of untreated samples in terms of infection rate and weight loss. The jute leaf extracts showed more pronounced inhibitory effects on Ecc-138 growth both in in vitro and storage experiments.

Electrochemical study on inhibitory effect of Aspirin on mild steel in 1 M hydrochloric acid

Abstract Aspirin was investigated as a good corrosion inhibitor for mild steel in 1 M hydrochloric acid at a temperature region from 303 to 333 K. The computed inhibition efficiency increases by increasing the inhibitor concentration and decreases by increasing the temperature. The investigation was done by weight loss, electrochemical measurements such as Tafel polarization and electrochemical impedance spectroscopy. Inhibition effect is attributed to the adsorption of inhibitor on the surface of the mild steel. The Tafel method reveals that the Aspirin acts as a mixed type inhibitor. Activation parameters suggest that the adsorption process is exothermic in nature. SEM photographs of mild steel in the absence and presence of inhibitor visualize the adsorption layer on the surface of the mild steel.

The effect of synthesis time on graphene growth from palm oil as green carbon precursor

Graphene is the new material that arises after carbon nanotubes (CNTs) era and has extraordinary optical, electronic and mechanical properties compared to CNTs. The 2D graphene is the sp2 carbon allotropes compared to other dimensionality. It also can be in three forms that are zero-dimensional, one-dimensional or three-dimensional. The different dimensionality also called fullerenes, nanotubes and graphite. Therefore, the graphene is known as centre potential materials in expanding research area than others ever. The 2cm × 2cm silicon wafer was seeded with nickel (Ni) at different thickness by using sputter coater. The palm oil, carbon source, was placed in the precursor furnace and the silicon was placed in the second furnace (deposition furnace). The palm oil will mix with Nitrogen gas was used as carrier gas in the CVD under certain temperature and pressure to undergo pyrolysis proses. The deposition temperature was set at 1000 °C. The deposition time varied from 3 minutes, 5 minutes and 7 minutes. Th...

Inhibition Effects of Chloroquinolines on Corrosion of Mild Steel in Hydrochloric Acid Solution

The corrosion inhibition efficiencies of four compounds namely N-[(1E)-(2-chloroquinolin-3-yl) methylene]-N-phenylamine(CQMA), N-(1E)-(2-chloroquinolin-3-yl) methylene]-N-(4-fluorophenyl) amine (CQMFA), N-(4-chloro phenyl)-N-[(1E)-(2-chloroquinolin-3-yl) methylene] amine (CQMCA), and N-(4-bromo phenyl)-N-[(1E)-(2-chloroquinolin-3-yl) methylene]amine (CQMBA) on mild steel corrosion in hydrochloric acid media were investigated using mass loss, potentiodynamic polarization and electrochemical impedance spectroscopy. For all the studied inhibitors the inhibition efficiency values were found to increase with increasing concentration up to 5.00 × 10−4 mol · dm−3. Scanning electron microscopic technique showed the formation of a thick film on the steel surface in the presence of inhibitors.

Comparison of Cobalt Based Catalysts Supported on MWCNT and SBA-15 Supporters for Fischer-Tropsch Synthesis by Using Autoclave Type Reactor

10 and 40 wt% Co/Multiwall Carbon Nanotubes (MWCNT) and 10 and 40 wt% Co/Santa Barbara Amorphous-15 (SBA-15) catalysts were prepared via incipient wetness impregnation method. It was characterized by Scanning Electron Microscopy, BET, X-ray Diffractometry (XRD), Transmission Electron Microscopy (TEM), Temperature-Programmed Reduction and H2 Desorption. A 200 ml hastelloy autoclave reactor was implemented to see the performance of the catalysts. It was observed that the performance of 40 wt% Co/SBA-15 was higher that other catalysts in terms of production of longer chain paraffins.