An effective combined treatment using malic acid and ozone inhibits Shigella spp. on sprouts

Sanitizing efficacy of malic acid and ozone on artificially inoculated radish (Raphanus sativa) and moong bean (Phaseolus aureous) sprouts was determined against Shigella spp. Malic acid and ozone alone reduced the pathogen populations less than 3 log in both sprouts following complete immersion and spraying. Whereas, combination of both the sanitizers reduced pathogen populations significantly (P < 0.05) by 4.4 log in radish and 4.8 log in moong bean sprouts. Following treatment, antioxidant status of sprouts in terms of polyphenols, flavonoids and reducing power and free radical scavenging activities against DPPH and ABTS did not change significantly (P > 0.05); a two fold (P < 0.05) increase in DPPH radical scavenging activity in radish sprouts was observed after combined treatment. Results of our study suggest a commercially applicable intervention strategy for the control of Shigella spp. in raw sprouts.     

Friction and wear characteristics of jatropha oil-based biodiesel blended lubricant at different loads

Around the globe there is demand for the development of bio-based lubricants, which will be biodegradable, nontoxic, and environmental friendly. This paper outlines the friction and wear characteristics of jatropha biodiesel-contaminated bio-lubricant using a pin-on-disc tribometer. To formulate the bio-lubricants, jatropha oil-based biodiesels were blended at the ratios 4, 12, and 20% by volume with the base lubricant SAE 20 W 40. Tribological characteristics of these blends were carried out at 3.8 m/s sliding velocity and loads applied were 50, 100, and 160 N. Experimental results showed that the lubrication regime that occurred during the test was boundary lubrication while the main wear mechanism was adhesive wear. During testing, the lowest wear was found with the addition of 4 and 12% jatropha oil-based biodiesel, and above this contamination, the wear rate was increased considerably. The addition of 4 and 12% jatropha oil-based biodiesel with the base lubricant acted as a very good lubricant additive, which reduced the friction and wear rate diameter during the test. It has been concluded that JBO 4 and JBO 12 can act as an alternative lubricant to increase the mechanical efficiency at 3.8 m/s sliding velocity and contribute to reducing the dependence on petroleum-based products.     

Effect of transition metal (Cu and Pt) doping/ co-doping on hydrogen gas sensing capability of graphene: A DFT study

Carbon nano-materials are found to demonstrate good hydrogen gas sensing capability and researchers are trying their modified derivatives for enhanced sensitivity. Studies have confirmed improvement in sensing performance of graphene when doped with N or Si or Sb. However, effect of the doping of graphene with transition metals of comparable size on its hydrogen sensing properties has not yet been studied. In the present study, we investigated the sensitivity of pristine graphene, Pt-doped graphene; Cu-doped graphene and Pt–Cu co-doped graphene surface towards hydrogen molecule adsorption utilizing density functional theory (DFT) by ab initio method. The adsorption energies for the optimized geometries have been calculated to probe the suitability and effectiveness of the modified graphene structures for Hydrogen sensing. In addition, the electronic properties for instance charge transfer analysis, band gap and density of states have also been taken into consideration. The reactivity of graphene surface for hydrogen adsorption was found to be greatly enhanced with Pt–Cu co-doped graphene surface as demonstrated by the adsorption energies and electronic properties.     

An optoelectronic instrument for the determination of sulphite in beverages

The paper describes an optoelectronic device that has been designed and developed to measure the sulphite concentration in beverages for quality evaluation. A selective and sensitive method for determination of sulphite is based on the reaction with pararosaniline acid bleached dye and formaldehyde solution, which gives violet colored complex having absorption maxima at 560 nm. Lambert–Beer’s law is obeyed in the concentration range up to 25 μg/ml (25 ppm) of test solution within an accuracy of ±0.05μg/ml (0.05 ppm). The instrument involves the use of high intensity green light emitting diode (LED) of wavelength 565 nm as light source. BPW21 photodiode having the relative spectral sensitivity above 90% in the range of 500–600 nm has been used as a detector, for the determination of sulphite concentration.     

An optimized hardware calibration technique for transmission of real-time applications in VoIP network

Multimedia Tools and Applications - Voice over Internet Protocol (VoIP) uses packet switching to transmit voice, video, data and chat services. VoIP applications depend upon various speech codecs...     

SNDR Measurement of Radio Over Fiber System Based on High Performance Generation Method Along with Optic Amplifier Link

Wireless Personal Communications - The medical enhancements have been improved to increase the life span of mankind. High penetration of Wireless Sensor Network in medical field helped the doctors...     

Synthesis and densification behaviour of magnesium aluminate spinel: Effect of Dy2O3

Magnesium aluminate spinels have been developed by reaction sintering of calcined alumina and calcined magnesia and its densification behaviour was studied in presence of Dy₂O₃. Green bar made from stoichiometric spinel composition with and without Dy₂O₃ were subjected to dilatometric study, densification study and microstructural evaluation by SEM. It was found that Dy₂O₃ additive does not have significant effect on the spinelisation but favours the densification of the spinel. Microstructure of sintered spinel without any additive is non-uniform with some exaggerated grain growth. Dy₂O₃ prevents the exaggerated grain growth and thereby helps in the densification process.     

Antiplasmodial and Antimalarial Activity of 3,5-Diarylidenetetrahydro-2H-pyran-4(3H)-ones via Inhibition of Plasmodium falciparum Pyridoxal Synthase

A series of 22 different 3,5-diarylidenetetrahydro-2H-pyran-4(3H)-ones (DATPs) were synthesized, characterized, and screened for their in vitro antiplasmodial activities against chloroquine (CQ)-sensitive Pf3D7, CQ-resistant PfINDO, and artemisinin-resistant PfMRA-1240 strains of Plasmodium falciparum. DATP 19 ( 3,5-bis(4-hydroxy-3,5-dimethoxybenzylidene)tetrahydro-2H-pyran-4(3H)-one) was found to be the most potent (IC₅₀ 1.07 μM) against PfMRA-1240, whereas 21 (3,5-bis(3,4,5-trimethoxybenzylidene)tetrahydro-2H-pyran-4(3H)-one) showed IC₅₀ values of 1.72 and 1.44 μM against Pf3D7 and PfINDO, respectively. Resistance indices (RI) as low as 0.2 to 0.5 for 10 (3,5-bis(4-nitrobenzylidene)tetrahydro-2H-pyran-4(3H)-one) and 20 (3,5-bis(3-nitrobenzylidene)tetrahydro-2H-pyran-4(3H)-one), and <1 for most other DATPs reveals their greater potency against resistant strains than the sensitive one. The single-crystal XRD data for DATP 21 are reported. In silico support was obtained through docking studies. Killing all three strains within 4–8 h, these DATPs showed rapid kill kinetics toward the trophozoite stage. Furthermore, DATP 18 (3,5-bis(quinolin-4-ylmethylene)tetrahydro-2H-pyran-4(3H)-one) inhibited PfPdx1 enzyme activity with IC₅₀ 20.34 μM, which is about twofold lower than that (IC₅₀ 43 μM) for an already known inhibitor 4PEHz. At an oral dose of 300 mg/kg body weight, DATPs 19 and 21 were found to be nontoxic to mice, and at 100 mg/kg body weight, DATP 19 was found to suppress parasitaemia, which led to an increase in median survival time by three days relative to untreated control mice in a malaria curative study.     

Sensing behavior of silica-coated Au nanoparticles towards nitrobenzene

In the present work, we report silica-stabilized gold nanoparticles (SiO₂/Au NPs) as a wide-range sensitive sensing material towards nitrobenzene (NB). Surface hydroxyl groups of silica selectively form Meisenheimer complex with electron-deficient aromatic ring of NB and facilitate its immobilization and subsequent catalytic reduction by Au cores. Silica-coated Au NPs were synthesized and characterized for their chemical, morphological, structural, and optical properties. SiO₂/Au NPs-modified electrodes were characterized with impedometric and cyclic voltammetric electrochemical techniques. SiO₂/Au NPs are found to have a higher optical detection window of range, 0.1 M to 1 μM and a lower electrochemical detection window of range, 10⁻⁴ to 2.5 × 10⁻² mM with a detection limit of 12.3 ppb. A significant enhancement in cathodic peak current, C ₁, and sensitivity (102 μA/mM) was observed with modified electrode relative to bare and silica-modified electrodes. The I _P was found to be linearly co-related to NB concentration (R ² = 0.985). The interference of cationic and anionic species on sensor sensitivity was also studied. Selectivity in the present sensing system may be further improved by modifying silica with specific functional moieties.