Short communication: On the potential use of materials with heterogeneously distributed parent and daughter isotopes as primary standards for non-U-Pb geochronological applications of laser ablation inductively coupled mass spectrometry (LA-ICP-MS)

Many new geochronological applications of laser ablation inductively coupled mass spectrometry (LA-ICP-MS) have been proposed in recent years. One of the problems associated with this rapid growth is the lack of chemically and isotopically homogeneous matrix-matched primary standards to control elemental fractionation during LA-ICP-MS analysis. In U-Pb geochronological applications of LA-ICP-MS this problem is often addressed by utilising matrix-matched primary standards with variable chemical and isotopic compositions. Here I derive a set of equations to adopt this approach for non-U-Pb geochronological applications of LA-ICP-MS.

Sr-bearing phosphates of the apatite supergroup from the alkaline rocks of the Konder pluton, Khabarovsk Krai

The paper presents a mineralogical description of Sr-bearing phosphates of the apatite supergroup found in eudialyte-aegirine-albite rocks of the Konder pluton, Khabarovsk krai. The Sr-dominant phases are associated with minerals of the lamprophyllite group and titanite, whereas the Ca-dominant phases are associated with calciocatapleite and kainosite-(Y), which are the products of the decomposition of eudialyte. The phosphates probably formed during post-magmatic alteration of host rock in a following sequence: stronadelphite > fuorostrophite > Sr-rich fuorapatite (fuorocaphite) > Na-REE-fuorapatite. Their variable chemical composition indicates decreasing Sr, Ba and F contents and increasing Ca, Na, REE and (OH) contents during crystallization. The crystallization sequence could refect a decrease in alkalinity of the mineral-forming conditions. Keywords: stronadelphite, fuorostrophite, fuorocaphite, Sr-rich fuorapatite, fuorapatite, alkaline rocks, hydrothermal alterations, Konder pluton, alkaline-ultramafc complexes.

Tunable and Enhanced Performance of Graphene-Assisted Plasmonic Sensor with Photonic Spin Hall Effect in Near Infrared: Analysis Founded on Graphene’s Chemical Potential and Components of Light Polarization

In this work, we propose a graphene-assisted plasmonic structure with photonic spin Hall effect (PSHE) for sensing applications in near infrared (NIR) with an emphasis on tunable and spin control aspects leading to enhanced performance. We comprehensively investigate PSHE in view of variable chemical doping of graphene monolayer in the structure and manipulation of the spin dependent splitting by considering single and cross polarization states. There is observed a considerable variation in spin shift due to increase in chemical potential or Pauli blocking, which fundamentally controls the light absorption by graphene. Our simulation results reveal that the amplified spin dependent shift is 1.13×104 times higher than the conventional spin dependent shift at 0.436 eV of graphene chemical potential. Further, this structure is utilised for sensing application, and it is observed that graphene-assisted plasmonic based structure possesses significantly greater spin dependent sensitivity (5.53 times), figure of merit (8.56 × 105 times), and extremely finer limit of detection (by a factor of 18.10) are achieved compared to the structure without graphene. The results indicate that chosing the proposed graphene-assisted plasmonic structure with variable chemical potential and light polarization components, an extremely enhanced sensing performance can be achieved. The results are consistent with the physical rationale and are particularly important for potential biosensing applications.

Process-Induced Changes in the Quantity and Characteristics of Grain Dietary Fiber

Daily use of wholegrain foods is generally recommended due to strong epidemiological evidence of reduced risk of chronic diseases. Cereal grains, especially the bran part, have a high content of dietary fiber (DF). Cereal DF is an umbrella concept of heterogeneous polysaccharides of variable chemical composition and molecular weight, which are combined in a complex network in cereal cell walls. Cereal DF and its distinct components influence food digestion throughout the gastrointestinal tract and influence nutrient absorption and other physiological reactions. After repeated consumption of especially whole grain cereal foods, these effects manifest in well-demonstrated health benefits. As cereal DF is always consumed in the form of processed cereal food, it is important to know the effects of processing on DF to understand, safeguard and maximize these health effects. Endogenous and microbial enzymes, heat and mechanical energy during germination, fermentation, baking and extrusion destructurize the food and DF matrix and affect the quantity and properties of grain DF components: arabinoxylans (AX), beta-glucans, fructans and resistant starch (RS). Depolymerization is the most common change, leading to solubilization and loss of viscosity of DF polymers, which influences postprandial responses to food. Extensive hydrolysis may also remove oligosaccharides and change the colonic fermentability of DF. On the other hand, aggregation may also occur, leading to an increased amount of insoluble DF and the formation of RS. To understand the structure–function relationship of DF and to develop foods with targeted physiological benefits, it is important to invest in thorough characterization of DF present in processed cereal foods. Such understanding also demands collaborative work between food and nutritional sciences.

Testate amoebae (Arcellinida and Euglyphida) from Pantanal dos Marimbús, Chapada Diamantina, Bahia state, Brazil, including new occurrences

Testate amoebae are single-celled protists whose protoplasm is contained within a carapace composed of gelatinous to imbricated chitinous plates having variable chemical compositions. We inventoried the testate amoebae community present in the plankton and periphyton of the Pantanal dos Marimbus swamp in Bahia state, Brazil. Sixty-five samples of plankton and periphyton were analyzed during May and September/2014 and April/2015. We identified 65 taxa of testate amoebae distributed in eight families, 15 genera, 45 species, and 16 varieties. The most representative families were Arcellidae, Centropyxidae, and Difflugiidae, corresponding to 24.6%, 19.7% and 14.8% of the taxa respectively. The periphyton had greater richness (59 taxa) than the plankton (39 taxa). Of the taxa found, 15 represent new records for Bahia and 14 for northeastern Brazil. The Marimbus Pantanal swamp showed an expressive richness of testate amoebae, and our data increases the number of species of these organisms known to Bahia and northeastern Brazil, where work with those organisms is still scarce.

The Search for Natural and Synthetic Inhibitors That Would Complement Antivenoms as Therapeutics for Snakebite Envenoming

A global strategy, under the coordination of the World Health Organization, is being unfolded to reduce the impact of snakebite envenoming. One of the pillars of this strategy is to ensure safe and effective treatments. The mainstay in the therapy of snakebite envenoming is the administration of animal-derived antivenoms. In addition, new therapeutic options are being explored, including recombinant antibodies and natural and synthetic toxin inhibitors. In this review, snake venom toxins are classified in terms of their abundance and toxicity, and priority actions are being proposed in the search for snake venom metalloproteinase (SVMP), phospholipase A2 (PLA2), three-finger toxin (3FTx), and serine proteinase (SVSP) inhibitors. Natural inhibitors include compounds isolated from plants, animal sera, and mast cells, whereas synthetic inhibitors comprise a wide range of molecules of a variable chemical nature. Some of the most promising inhibitors, especially SVMP and PLA2 inhibitors, have been developed for other diseases and are being repurposed for snakebite envenoming. In addition, the search for drugs aimed at controlling endogenous processes generated in the course of envenoming is being pursued. The present review summarizes some of the most promising developments in this field and discusses issues that need to be considered for the effective translation of this knowledge to improve therapies for tackling snakebite envenoming.

Proposals for Antimicrobial Testing Guidelines Applied on Ajowan and Spanish Lavender Essential Oils

To fight the rising resistance of microorganisms to antibiotics, a strategy followed by several researchers is to focus on natural compounds, such as essential oils, as a source of potent antibacterial compounds. These last decades, hundreds of original papers have been written about microbiological assays that prove the antibacterial activity of essential oils and their use in the medical field. But can we really compare all the data available in the literature when the raw material, the microbiological assays, and/or the strains are different from one article to another? This review will point out the differences and the inadequate practices found in published articles that tested 2 lesser-studied essential oils–Spanish lavender and the ajowan–by the broth dilution method against Staphylococcus aureus, a human pathogenic bacterium. Many pitfalls were found in the literature, for example, a variable chemical composition rarely underlined by the authors, unidentified strains or clinical strains used without a related antibiogram, a lack of quality controls, and the assertion of questionable positive results. At last, some general guidelines that should be followed by every scientific researcher will be discussed.

Effect of Alloying Additives and Microadditives on Hardenability Increase Caused by Action of Boron

The presented work was aimed at evaluating influence of boron on hardenability of steel quantitatively and evaluating this effect during complex use of boron with other alloying additives like chromium, vanadium and titanium. For this purpose, eight melts with variable chemical compositions were prepared. From the ingots, cylindrical specimens with normalized dimensions according to EN ISO 642:1999 were cut out and subjected to full annealing at 1200 °C and to normalizing at 900 °C. Such specimens were subjected to the hardenability Jominy test. In order to distinguish the influence of boron on hardenability of a given melt and thus to eliminate the differences resulting from its chemical composition, grain size and austenitizing temperature, the obtained ideal critical diameter was corrected and the boron effectiveness factor was determined. The performed examinations and analyses showed that inadequate quantities of microadditives result in losing the benefits coming from introduction of boron as the hardenability-improving element and can even result in a reduction of hardenability of the boron-containing steel.