Effect of γ-irradiation on the growth of ZnO nanorod films for photocatalytic disinfection of contaminated water

The growth of ZnO nanorods on a flat substrate containing γ-irradiated seeds and their ability to photocatalytically eliminate bacteria in water were studied. The seed layer was obtained, by the spray pyrolysis technique, from zinc acetate solutions γ-irradiated within the range from 0 to 100 kGy. Subsequently, to grow the rods, the seeds were immersed in a basic solution of zinc nitrate maintained at 90 °C. The rate of crystal growth on the seed layer during the thermal bath treatment was kept constant. The resulting materials were characterized morphologically by scanning electron and atomic force microscopies; X-ray diffraction was used to study their morphology and structure and ultraviolet-visible spectroscopy to determine their absorbance. The obtained seed films were morphologically dependent on the radiation dose and this was correlated with the ZnO nanorod films which presented a texture in the (002) direction perpendicular to the substrate. The rods have a hexagonal mean cross section between 20 and 140 nm. Using these rods, the photocatalytic degradation of Escherichia coli bacteria in water was studied; a positive influence of the crystalline texture on the degradation rate was observed.     

Simulation of electrical field for the formation mechanism of Bird’s Nest patterned structures by electrospinning

In our previous work, it was found that large Bird’s Nest patterned nanofibrous membranes can be simply electrospun from chlorinated polypropylene solution doped with an ionic liquid, and a plausible formation mechanism of Bird’s Nest patterned architectures was proposed. Here, we use Ansoft Maxwell version 12 software (3D, electrostatic solver) to simulate the electrical field distribution of the electrospinning setup, and to clarify the rationality of proposed formation mechanism. Calculation results clearly show that the introduction of charged nanofibrous bundles would produce a similar patterned electrical field distribution, which definitely confirms the important role of surface residual charges. The proposed mechanism can be well extended to other polymer systems including polystyrene, poly(acrylonitrile-co-acrylic acid) and chitosan/poly(ethylene oxide).     

Effect of the direction of the earth’s magnetic field lines on corrosive wear

In this work, the effect of the direction of the Earth’s magnetic field lines on the corrosive wear of steel samples in an aggressive medium was studied, and a study algorithm and a data processing algorithm were described.     

Application of 1H-NMR-based metabolomics for detecting injury induced by long-term microwave exposure in Wistar rats’ urine

There has been growing public concern regarding exposure to microwave fields as a potential human health hazard. This study aimed to identify sensitive biochemical indexes for the detection of injury induced by microwave exposure. Male Wistar rats were exposed to microwaves for 6 min per day, 5 days per week over a period of 1 month at an average power density of 5 mW/cm(2) (specific absorption rate of 2.1 W/kg). Urine specimens were collected over 24 h in metabolic cages at 7 days, 21 days, 2 months, and 6 months after exposure. (1)H NMR spectroscopy data were analyzed using multivariate statistical techniques. Urine metabolic profiles of rats after long-term microwave exposure were significantly differentiated from those of sham-treated controls using principal component analysis or partial least squares discriminant analysis. Significant differences in low molecular weight metabolites (acetate, succinate, citrate, ketoglutarate, glucose, taurine, phenylalanine, tyrosine, and hippurate) were identified in the 5 mW/cm(2) microwave exposure group compared with the sham-treated controls at 7 days, 21 days, and 2 months. Metabolites returned to normal levels by 6 months after exposure. These data indicated that these metabolites were related to the perturbations of energy metabolism particularly in the tricarboxylic acid cycle, and the metabolism of amino acids, monoamines, and choline in urine represent potential indexes for the detection of injury induced by long-term microwave exposure.     

Iranian chemist’s efforts to provide various effective methods for the synthesis of xanthenes

Xanthenes and their derivatives as very important classes of organic compounds are key structural elements of many biologically active compounds. These materials are important heterocyclic nucleus of various dyes and drugs. Because of their wide range of pharmacological, industrial and synthetic applications, many methods for the preparation of xanthenes are reported in the literature. In recent years, among the other chemists, introduction of new methods for the preparation of these types of compounds has attracted the attention of Iranian chemists. The result of these efforts is the introduction of appropriate, effective and efficient methods. In this paper, we have a brief review on these methods and their main advantages and important applicabilities.     

Linus Pauling’s quest for the structure of proteins

Linus Pauling, arguably the greatest chemist of the twentieth century, never publicly admitted that there was a race for the determination of the structure of the most important biopolymers. But according to his competitors there was a race, in fact, there were two, and Pauling won one and lost the other. He had a tremendous amount of ideas, many of them worthless, but a few were spectacular. Not only did he make seminal discoveries, he was also a master of announcing them in a most dramatic way. Eventually, Pauling shifted toward politics and controversial issues, but his science ensured him his place among the greats. Here, we follow Pauling’s route to the discovery of the alpha-helix; the defeat of the star-studded British team in the same quest; and a seemingly unrelated story about the fate of the theory of resonance that assured Pauling’s victory yet at the same time it was excommunicated in the Soviet Union.     

Use of 1,2-napthoquinone-4-sulfonate (folin’s reagent) for the thin-layer chromatographic detection of p-Phenylenediamine

JPC – Journal of Planar Chromatography – Modern TLC -     

Molecular interpretation of Trouton’s and Hildebrand’s rules for the entropy of vaporization of a liquid

The entropy of vaporization at a liquid’s boiling point is well approximated by Trouton’s rule and even more accurately by Hildebrand’s rule. A cell method is used here to calculate the entropy of vaporization for a range of liquids by subtracting the entropy of the gas from that of the liquid. The liquid’s entropy is calculated from the force magnitudes measured in a molecular dynamics simulation based on the harmonic approximation. The change in rotational entropy is not accounted for except in the case of liquid water. The predicted entropies of vaporization agree well with experiment and Trouton’s and Hildebrand’s rules for most liquids and for water except other liquids with hydrogen bonds. This supports the idea that molecular rotation is close to ideal at a liquid’s boiling point if hydrogen bonds are absent; if they are present, then the rotational entropy gain must be included. The method provides a molecular interpretation of those rules by providing an equation in terms of a molecule’s free volume in a liquid which depends on the force magnitudes. Free volumes at each liquid’s boiling point are calculated to be ～1 Å³ for liquids lacking hydrogen bonds, lower at ～0.3 Å³ for those with hydrogen bonds, and they decrease weakly with increasing molecular size.     

On the use of the ‘uncertainty budget’ to detect dominant terms in the evaluation of measurement uncertainty

In the evaluation of measurement uncertainty, the uncertainty budget is usually used to identify dominant terms that contribute to the uncertainty of the output estimate. Although a feature of the GUF method, it is also recommended as a qualitative tool in MCM by using ‘nonlinear’ equivalents of uncertainty contributions and sensitivity coefficients. In this paper, the use of ‘linear’ and ‘nonlinear’ parameters is discussed. It is shown that when and only when the standard uncertainty of the output estimate is nearly equal to the square root of the sum of the squares of the individual uncertainty contributions, will the latter be a reliable tool to detect the degree of contribution of each input quantity to the measurand uncertainty.     

IAEA-MEL’s underground counting laboratory (CAVE) for the analysis of radionuclides in the environment at very low-levels

Summary An underground laboratory for low-level gamma- and beta-spectrometry has been constructed at IAEA-MEL, Monaco, for the analysis of environmental radionuclides. The laboratory is situated at a depth of 35 m water equivalent underground and equipped with 4, large volume HPGe detectors placed in a common lead shield with anti-cosmic plastic scintillator shielding. There is also an anti-Compton gamma-spectrometer, comprized of an HPGe detector and NaI(Tl) shielding, and finally, a Quantulus liquid scintillation spectrometer. The performance of the gamma-spectrometers with different shielding settings/adjustments are discussed, as well as their possible applications in the analysis of natural and anthropogenic radionuclides in the marine environment.     

The contribution of gas chromatography to the resynthesis of the post-Byzantine artist’s technique

Gas chromatographic analysis of ethyl chloroformate derivatives of samples taken from the paint layers of post-Byzantine panel paintings permitted the successful characterisation of the different binding media used in them. This paper describes an analytical study of various post-Byzantine binding media such as egg yolk and egg/oil emulsion, using gas chromatography. The characterisation of these icons’ binding media is an important task, as it contributes to our understanding of and the reconstruction of the post-Byzantine artists’ palette. It also enables us to investigate the validity of our assumptions about the influences of Venetian style on Greek icon painting techniques from the sixteenth to the early nineteenth century, which up to now have been based on information in artists’ handbooks. The methodology involves two experimental steps: (1) hydrolysis of the proteins and triglycerides in the binding media to obtain free amino acids and fatty acids, and (2) the formation of ethyl chloroformate derivatives via derivatization with ethyl chloroformate (ECF). This methodology is of considerable interest, since it permits the identifcation of the nature of the proteinaceous binders used in these works through the simultaneous derivatization and determination of amino acids and fatty acids. Advantages of this methodology include the small quantity of sample required and the minimum preparation time involved. The proteinaceous media can be determined based on the ratios of seven stable amino acids, while the type of emulsions and drying oils used can be determined from the fatty acid ratio. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

A convenient procedure for the preparation of Garner’s aldehyde

The palladium/silane reduction of a serine thioester derivative allows for the preparation of enantiomerically pure Garner’s aldehyde from serine, in gram quantities within 24 h.     

Accreditation to ISO 17025:2005 for the Radioactivity Metrology Group of the UK’s National Physical Laboratory

In the mid 1990s, the National Physical Laboratory (NPL) took the decision to seek external accreditation to the then UK national accreditation standard (M10, M10 supplement and M11) through the NPL’s National Measurement Accreditation Service (NAMAS). This paper details the reasoning behind that initial decision and, in particular, how this impinged on the day-to-day activities of the NPL’s Radioactivity Metrology Group (RMG). In the intervening decade, the accreditation standard has changed considerably; accreditation is now to the international standards ISO 9001:2000 (Quality Management Systems: Requirements) and ISO 17025:2005 (General Requirements for the Competence of Testing and Calibration Laboratories); accreditation is now carried out by a wholly separate successor organization to NAMAS, the United Kingdom Accreditation Service (UKAS). To meet the new accreditation requirements the RMG: realigned it’s scope of work; streamlined and consolidated written procedures, references and appendices; centralized the collection of written procedures, and clarified the document identification system. Future developments will include efforts for RMG accreditation for conducting proficiency tests and providing reference materials.     

Conference Cluster 2021 (to the 90th anniversary of G. A. Krestov’s birth)

Russian Chemical Bulletin -     

Determination of the emanation coefficient and the Henry’s law constant for the groundwater radon

The radon emanation coefficient (ε) from aquifer rock and the Henry’s law constant (H) of radon were determined by measuring activity concentrations using liquid scintillation counter (LSC). For the evaluation of the method, the coefficients were measured at 0, 10 and 20 °C and the temperature dependency of the coefficients was compared with others. The radon emanation coefficients from the rock particles used in this work are 0.0845, 0.1007 and 0.1308 at 0, 10 and 20 °C, respectively. The dimensionless Henry’s law constants for the groundwater used in this work are 0.994, 1.153 and 2.641 at 0, 10 and 20 °C, respectively. The results show a good agreement with those in literatures.     

Network pharmacology-based screening of the active ingredients and potential targets of the genus of Pithecellobium marthae (Britton & Killip) Niezgoda & Nevl for application to Alzheimer’s disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with synaptic dysfunction, pathological accumulation of β-amyloid (Aβ), and neuronal loss. Given the prevalence of AD and the lack of effective long-term therapies, there is a pressing need to discover viable leads that can be developed into clinically approved drugs with disease-modifying effects. The analysis of current reported literatures confirms the importance of the plants of Pithecellobium genus as candidate against AD. Hence, it is necessary to identify selective anti-dementia agents from this genus. To explore potential compounds with marked effect on AD in Pithecellobium genus, a compound database based on the methods of network pharmacology prediction was established in this paper by constructing the compound-disease target network. The result showed that the most effective compound in the plants of this genus might be (7′R,8′R)-7′-methoxyl strebluslignanol, and the most potential target might be Macrophage colony-stimulating factor 1 receptor.