Boron Activity Research Articles

Kaolin, boron, and zinc increase photosynthetic activity and mitigate the effects of light stress in heliconia grown under semi-arid conditions

Tropical flowers species of high commercial importance such as heliconia, if grown in semi-arid regions, can have their photosynthesis compromised and, consequently, flower production, due to high irradiation. Foliar applications of kaolin and the mineral nutrients boron and zinc may be an alternative for reducing the harmful effects of light stress. Thus, the objective of this study was to evaluate the effects of the application of these mitigating substances on physiological aspects in two species of heliconia grown under semi-arid conditions. The experimental design was randomized blocks in split-plot scheme, with four repetitions and four plants per replication. The plots consisted of two species of heliconias (H. psittacorum cv. Red Opal and H. bihai cv. Lobster Claw Two) and the subplots corresponded to three light stress mitigating substances (kaolin, boron + zinc, and control). The species H. psittacorum showed higher chlorophyll indexes, photosynthesis rate, stomatal conductance, and transpiration rate than the species H. bihai. The applications of kaolin and the mineral nutrients boron + zinc caused increases in the chlorophyll a and total chlorophyll indices, photosynthesis rate, carboxylation efficiency, effective quantum yield of photosystem II, leaf temperature, and vapor pressure deficit in plants of H. bihai and H. psittacorum. It is concluded that the foliar application of kaolin and the minerals boron and zinc reduce the harmful effects caused by high luminosity, with emphasis on the kaolin particle film, which promoted better photosynthetic performance and reduced the effects of non-stomatic limitation of photosynthesis, being a promising strategy for the cultivation of heliconia in semi-arid conditions. In addition, both kaolin and the minerals boron and zinc promote the production of flowering stems of heliconia with better quality and post-harvest durability.

Effects of Myrtus communis L. Extract and Apocynin on Lens Oxidative Damage and Boron Levels in Rats with a High Fat-Diet.

Objectives:Nutritional obesity causes oxidant damage in the body and cataract formation in the lenses by increasing the formation of free radicals. Myrtus communis leaf extracts (Myr) have antioxidant properties, and apocynin (Apo) is an effective NADPH-oxidase inhibitor. The data on tissue boron levels are quite lacking. The aim of this novel study was to investigate the effects of Myr and Apo treatment on boron levels and oxidative lens damage in rats fed a high-fat diet (HFD).Materials and Methods:Wistar albino male rats were randomly divided into four groups: the control group, HFD group, HFD + Myr group, and HFD + Apo group. Body weight and blood lipids were determined before and after the experiment. After decapitating the rats, the lenses were removed and homogenized. Catalase (CAT) and superoxide dismutase (SOD) activities and boron, malondialdehyde (MDA), and reduced glutathione (GSH) levels in the lens homogenates were determined.Results:The HFD increased serum triglyceride (p<0.05), total cholesterol level (p<0.001), body weight (p<0.001), and lens MDA levels (p<0.01) and decreased lens GSH (p<0.05) and boron level (p<0.01), SOD (p<0.001), and CAT activity (p<0.001). However, Myr and Apo treatment reduced the rats’ body weight (p<0.001), serum triglyceride (p<0.05), and total cholesterol level (p<0.001) and increased lens boron (p<0.01; p<0.001), GSH levels (p<0.05; p<0.01), and CAT activity (p<0.001).Conclusion:Both Myr and Apo may be able to reduce oxidative stress in the lenses of obese rats caused by HFD by increasing boron levels.

The NIP Genes in Sugar Beet: Underlying Roles in Silicon Uptake and Growth Improvement

Silicon (Si) can stimulate plant growth and stress resistance. This study aimed at elucidating the physiological responses and molecular characterization of different NIP (nodulin 26-like intrinsic protein) genes in sugar beet. The addition of exogenous Si increased plant biomass and Si concentration in the root and shoot, implying that increased Si uptake has beneficial effects on sugar beet. The quantitative gene expression analysis showed a significant upregulation of the BvNIP5–1 gene in roots, while the BvNIP1–1, BvNIP6–1, BvNIP7–1, and BvNIP-type were unchanged following Si supplementation. It suggests that BvNIP5–1 is one of the genes localized in the plasma membrane responsible for Si uptake in sugar beet. Besides, the BvNIP5–1 gene contained promoter, transcription start site, transcription binding site, and PolyA at 800 bp, 528 bp, 557 bp, and 1637 bp, respectively. The MEME results further revealed the association of three motifs related to major intrinsic protein (MIP). In the phylogenetic tree, the BvNIP5–1 showed a close association with CqNIP5–1, AnNIP2–1 and SoNIP5–1. Interactome analysis showed functional partnership of aquaporin SIP1–2 and SIP2–1 genes with NIP genes in sugar beet. In addition, BvNIP5–1 possessed close association with several functional partners (BOR1, BOR1, NodGS, SIP1A, ACR3) and co-expressed genes (i.e., AtNIP5–1, AtBOR1, AtNodGS, AtSIP1A, AtACR3) of Arabidopsis thaliana mainly responsible for boron, arsenite, and aquaporin transport activity. NIP promoters revealed cis-regulatory elements linked to auxin, salicylic acid, and methyl jasmonate-responsive factors. These findings may advance our understanding of Si transporters underlying growth and stress tolerance in sugar beet.

Prospects of Using Boron Powders As Fuel. II. Influence of Aluminum and Magnesium Additives and Their Compounds on the Thermal Behavior of Boron Oxide

Physicochemical changes occurring in an oxide shell of boron particles during heating are extremely important for the oxidation and combustion of boron, including those in solid propellant compositions. The Al2O3, MgO, MgF2, Al, and Mg impurities were experimentally discovered in an oxide layer on boron particles obtained by various methods. The goal of this work is to determine the effect of these impurities on the thermal behavior of boron oxide, with particular attention paid to evaporation of B2O3. The temperature and thermal effects of reactions between the components are thermoanalytically determined, and the processes of dehydration, melting, and evaporation of boron oxide are analyzed in detail. The enthalpy of evaporation of boron oxide, starting at a temperature above 1300°C is experimentally determined, and is equal to 347 ± 3 kJ/mol. An interaction is observed between magnesium fluoride and boron oxide at a temperature of about 1000°C with a mass loss corresponding to the content of magnesium fluoride and the formation of gas-phase boron fluoride. It is established that boron dissolved in oxide has virtually no effect on the evaporation of the boron oxide melt, while the addition of Al2O3or MgO significantly increases its thermal stability. Based on the analysis of the results obtained, an assumption is made about the effect of impurities on boron activity in the processes of boron ignition and combustion.

Boron activity in the inactive Li2MnO3 cathode material

Boron substituted Li2MnO3 cathode materials have frequently been studied and found to be inactive. In this reseach, crystal and electronic properties of the Li-ion cathode material with boron substitution having general formula; “Li2Mn1-xBxO3” (where x has values of 0.00, 0.05, 0.10, 0.15 and 0.20, respectively) were studied. The study revealed that, with the substitution of boron atoms in the manganese coordinates in the Li2MnO3 cathode materials, boron atoms acted as a landmark for the parent oxides by forming LiBO2 crystal domains. In the studied samples, boron atoms were determined as the key to construct new crystals and to restrict the excess of oxygen in the materials. Beyond the boron coordinations, the manganese atoms formed a cubic LiMn2O4 crystal structure which was reported to have good electrochemical properties. With the formation of the LiMn2O4 crystal, the substituted samples became a polycrystalline material with Li2MnO3- LiBO2- LiMn2O4 crystals. The obtained structure in the cathode materials have similarity with the general formula xLi2MnO3·(1-x)LiMn2O4 which had been reported to have good intercalation and electrochemical properties.

Effects of Nb2O5 and Gd2O3 doping on boron volatility and activity between glass seals and lanthanum-containing cathode

In planar Solid Oxide Fuel Cells (SOFCs), the boron species volatilize from glass seals, and react with lanthanum-containing cathodes (i.e., La0.6Sr0.4Co0.2Fe0.8O3−δ, LSCF) to form LaBO3 under cathodic polarization, which decomposes the perovskite structure and consequently decreases the electrochemical activity of cathode. In this study, Nb2O5 and Gd2O3 are added to an aluminoborosilicate glass to reduce the boron volatility from glass and the reaction between sealing glass and LSCF cathode. Both Nb2O5 and Gd2O3 doping increases the network connectivity, but Nb2O5 doping enhances the [BO3]→[BO4] transition and reduces the boron volatility from glass seals, thus effectively suppressing the deposition and poisoning of boron contaminants on the LSCF cathode. However, an obvious degradation of the electrocatalytic activity of LSCF occurs in the presence of Gd2O3-doped glass. The relationship between glass structure and glass/cathode interaction has been established to provide useful information for designing stable sealing materials for SOFC applications.

Can Boron and Nitrogen Co-doping Improve Oxygen Reduction Reaction Activity of Carbon Nanotubes?

Two kinds of boron and nitrogen co-doped carbon nanotubes (CNTs) dominated by bonded or separated B and N are intentionally prepared, which present distinct oxygen reduction reaction (ORR) performances. The experimental and theoretical results indicate that the bonded case cannot, while the separated one can, turn the inert CNTs into ORR electrocatalysts. This progress demonstrates the crucial role of the doping microstructure on ORR performance, which is of significance in exploring the advanced C-based metal-free electrocatalysts.

Not boring at all

The element boron is not renowned among biologists, short of a few specialists who know that it is an essential nutrient for plants and an element in boromycin—an antibiotic compound produced by Streptomyces . Yet, on the whole, molecular biologists and, in particular, those in drug development seem to have little use for carbon's left‐hand neighbour in the periodic table. This is about to change. Currently, boron is largely produced in Turkey and the USA, and is used in a wide range of products, including glass, detergents, fire retardants, fibres to reinforce plane fuselages and body armour, and in superhard materials. Now, both researchers and the pharmaceutical industry are showing an increasing interest in boron as an alternative to carbon in drug design. > …both researchers and the pharmaceutical industry are showing an increasing interest in boron as an alternative to carbon in drug design A series of recent scientific and commercial developments indicate that boron‐based compounds are interesting drug candidates against all disease categories and might even speed up drug development. Pharmaceutical companies have already increased their boron research, particularly GlaxoSmithKline (GSK; Brentford, UK), which announced a US$2.5 billion investment in the US company Anacor (Palo Alto, CA, USA) in November 2008. Anacor was founded in 2002 to develop boron‐based antibacterial drugs, but has since expanded into antivirals and other targets with its boron‐based platform. Co‐founders Lucy Shapiro and Stephen Benkovic began collaborating in 2001 to look for novel inhibitors of several newly identified bacterial target sites that, they thought, could lead to more effective antibiotics. “They randomly inserted boron and got good activity,” said David Perry, CEO of Anacor. This serendipitous discovery led to the formation of Anacor a year later. “We were lucky,” Perry conceded. “At that stage we had no idea what the broader potential of boron …

Formation of boride layers on steel substrates

AbstractBoronizing coatings were prepared by means of pack cementation technique. It was found that using the appropriate substrate and controlling parameters of the boribing process such as boron activity of the mixture, temperature and time of treatment, it is possible to obtain a structure predominantly consisting of the Fe2B phase. In the present study low alloy ferritic steels were chosen as substrates. Changing the boron carbide concentration in the mixture and the temperature and time of boronizing process the conditions of the boronizing were altered. As a result the formation of the Fe2B phase is enhanced. Characterization of the as‐borided steels is discussed based on X‐ray diffraction and Curie temperature measurements. (© 2006 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Environmental boron exposure and activity of delta-aminolevulinic acid dehydratase (ALA-D) in a newborn population.

Following boron intake, multiple effects have been observed in animal experiments. However, human data is lacking, and no data is available on the ability of boron to accumulate in fetal tissues. Positive responses in animal species suggest that developmental toxicity may be an area of concern in humans, following exposure to boron. Two hypotheses have seemed to account for the multiple effects described in scientific findings. One hypothesis is that boron is a negative regulator that influences a number of metabolic pathways by competitively inhibiting some key enzyme reactions. The other hypothesis is that boron has a role in ionic membrane transport regulations. To better understand boron potential toxicity, the present study examined the relationship between boron exposure and some key enzymes, well-known for their affinity for mineral elements, such as delta-aminolevulinic acid dehydratase (ALA-D), and two fundamental enzymes having a role in ionic membrane transport regulations (Ca-pump and Na(+)K(+)-ATPase). We investigated the potential effects of an environmental boron exposure on the activity of these enzymes in an urban population of 197 "normal" newborns. Environmental boron exposure was assessed in placental tissue. Because of the well-known inhibiting effect of lead on these enzymes, cord blood and placental lead were also analyzed. After adjustment for potential confounders, including lead, placental boron levels were negatively significantly correlated to ALA-D activity while Ca-pump and Na(+)K(+)-ATPase activities did not seem to be affected by the level of boron exposure. Given boron's ability, as a Lewis acid, to complex with hydroxyl groups, we suggest that such a mechanism would explain the inhibiting effect of boron on ALA-D.

Accurate and efficient determination of boron content in volcanic rocks by neutron induced prompt gamma-ray analysis

An accurate and efficient analytical method using neutron-induced prompt γ-ray was developed for the determination of boron contents in volcanic rocks. We corrected the effect of sample geometry and flux fluctuation by using silicon as an internal standard. However, we found that the slopes of the calibration line vary among volcanic samples with different matrix. Because the increase of boron activity correlates positively with γ-ray count rate of hydrogen (water), we call this as the hydrogen effect. The hydrogen effect was confirmed by our experiment in which the boron activities showed systematic increase with the amount of added hydrogen (water). Most volcanic rocks, however, contain little water (<2 wt.%) to show this effect. We determined boron contents in various volcanic rocks in order to confirm the validity of the procedure that we established. The analyzed boron contents agreed well with the previous reported values. For efficient PGA of boron in volcanic rocks, we recommend JB-2 (GSJ standard rock) as a single geochemical standard, because of its high boron content (31.2 ppm).

Development and growth of boron-modified and germanium-doped titanium-silicide diffusion coatings by the halide-activated, pack-cementation method

A halide-activated, cementation pack has been developed to codeposit either silicon and boron or else silicon and germanium in a single processing/reaction step to grow Ti-silicide diffusion coatings on commercially pure (CP) titanium, Ti-22Al-27Nb, and Ti-20Al-22Nb. Since boron is nearly insoluble in TiSi2, a TiB2 layer is localized at the surface of the B-modified silicide coatings. The thickness of the TiB2 layer is controlled by the choice of boron activity and halide activator in the pack. Germanium is soluble in the Ti-silicide layers but inhomogeneously distributed in the Ge-doped silicide coating. The germanium content is controlled by choices of the Si-to-Ge ratio and the halide activator in the pack. The growth kinetics for the five-layered B-modified silicide coatings are generally similar to the undoped silicide coatings. The growth mechanism for the five-layered Ge-doped silicide coatings is generally different from the undoped silicides. The growth of dual-layer Ti-boride coatings was also studied.

Electronic defects induced in p- and n-type silicon by SF6 plasma etching

Electronic defects induced in p- and n-type silicon by SF6 plasma etching in microwave multipolar plasma reactors have been studied by capacitance spectroscopy, spreading resistance, and infrared absorption measurements. A passivation of the boron and phosphorus electrical activity is associated with hydrogen contamination due to residual water traces in the reactor. Deep level transient spectroscopy measurements reveal several deep levels in the gap after etching. They are located at 0.51 and 0.36 eV above the valence band in the p-type boron-doped silicon and at 0.4 and 0.24 eV below the conduction band in the n-type phosphorus-doped silicon. We studied the influence of plasma parameters, gas nature, and postetch thermal annealing on the H(0.51), H(0.36), E(0.4), and E(0.24) levels. The results show that the occurrence of the H(0.51) and E(0.4) levels is correlated with displacement damage production and the presence of SFx species in the plasma. The H(0.36) level is caused by the formation of a carbon-interstitial-related defect whereas the E(0.24) level is attributed to the V–V divacancy.

Tendency to thermaleembrittlement in a martensitic Cr-Ni-Mo steel with titanium and boron additions

1. Adding 0.02–0.03% Ti and 0.002–0.003% B to the 08Kh4N2M martensitic steel significantly reduces the tendency to thermal embrittlement. The increase in the critical embrittlement temperature (T50) for this steel with 0.009–0.020% P after soaking for 2000 h at 450°C was no more than 15°C. 2. The favorable effect of coalloying with titanium and boron on the resistance to thermal embrittlement is maintained in the 08Kh4N2M with an increased phosphorus concentration (0.035%). 3. The excellent resistance to thermal embrittlement of the 08Kh4N2M steel due to Ti and B additions is due to the fact that boron prevents phosphorus segregation along the grain boundaries. Concurrently, the titanium combines with the nitrogen to improve the boron activity.

Activities of boron in the binary Ni-B and the ternary Co-Fe-B melts

Activities of boron in the binary Ni-B and the ternary Co-Fe-B melts have been directly determined by the electromotive force (emf) measurement. A boron crystal was mainly used as the reference electrode, and a ternary 29 wt pct B2O3-42 wt pct CaO-29 wt pct Al2O3 oxide melt was used as the electrolyte. Large negative deviations from Raoult’s law have been found in both the binary and the ternary systems. The activity of nickel has been calculated from the measured boron activity by means of the Gibbs-Duhem equation. Standard Gibbs energies of formation of Ni3B (s), Fe2B (s), and Co3B (s) were estimated and compared with available data.

Concentrations en bore de la “nappe maestrichtienne” du Sénégal: leur influence sur l'aptitude des eaux à l'irrigation

High boron concentrations (>1mgl −1), dangerous for many plants species, have recently been observed in the West central part of the Senegalese Senonian aquifer. These excessive boron concentrations in this zone unsuitable for irrigation because of bad water quality create additional contrainst. The use of these waters for irrigation is not adviced, but locally in the absence of any water ressources it could be tolerated after necessary precautionary meausures. The close association beetween salinity and boron concentrations oblige that salinity should first be considered. Any precaution or treatment suggested for salinity has a positive influence on boron activity. The specific contrainst related to boron will be the choice of plants which are boron resistant.

Vaporization thermodynamics of Pd-B(Liquid) and Pd-B-C(Liquid)

The Pd-B and Pd-B-C liquid phases were studied by the Knudsen effusion technique to determine the variation of palladium and boron activity with composition and temperature. Equations are given which describe the thermodynamic properties throughout the liquid phase region. In addition, the phase boundary composition was determined between the liquid and the respective multiphase containing excess boron. The phase forms solid boron at 1600 K when the composition reaches Pd 0.55B 0.45 and the palladium activity is 0.0186. Dissolved carbon causes the palladium activity to increase and the phase boundary to shift to a higher boron composition.

Effect of Exchangeable Ions and Ionic Strength on Boron Adsorption by Montmorillonite and Illite

AbstractThe effects of exchangeable Na and Ca and the ionic strength of NaCl and CaCl2 solutions on the boron adsorption by the Na and Ca forms of montmorillonite and illite at pH 9 were studied. The boron adsorption by montmorillonite was greater for the Ca form than for the Na form at any boron activity in solution and at any ionic strength. For example, the amount of boron adsorbed by Na- and Ca-montmo-rillonite was 2.9 and 4.3 μmole/g, respectively, at an ionic strength of 0.36 and a boron activity of 0.875 mmole/liter in equilibrium solution. The boron adsorption by illite was much greater than by montmorillonite. For example, the amount of boron adsorbed by Na-montmorillonite and Na-illite was 1.5 and 8.7 μmole/g, respectively, at an ionic strength of 0.02 and a boron activity of 0.5 mmole/liter. However, the nature of the exchangeable cation had little effect on the boron adsorption by illite. The effect of the ionic strength on the boron adsorption by Na-montmorillonite was greater than that observed for either Camontmorillonite or illite. The data suggest that the negative electric field around the clay particles is one of the main factors controlling boron adsorption at alkaline pHs.

The influence of alloying element additions on the boriding of steels

The influence of the alloying elements carbon (0%–2%), nickel (0%–14%) and chromium (0%–26%) on the boriding characteristics of steels was systematically studied using a new boriding technique on laboratory-cast binary and ternary steels and on industrial steels. The concentration profiles, phases (structure and texture) and microstructures were determined by glow discharge optical spectroscopy, X-ray analysis and classical metallographic techniques. In high concentrations, all three elements tend to favour the formation of relatively flat boride layers, even when these layers are highly textured, in contrast with the single-phase acicular Fe 2B layer obtained on low carbon steels. The concentration profiles developed during boriding revealed different behaviours: carbon segregates towards the matrix, nickel segregates towards the surface, whereas chromium is scarcely affected. The segregation of nickel to the surface at high boron activities severely hinders the successful boriding of highly alloyed steels, e.g. austenitic stainless steels. It is shown, however, that low boron activity gaseous phase boriding can produce good quality homogeneous Fe 2B layers with reduced nickel segregation.

Thermodynamics of Aluminium‐ and Magnesium‐Base Interstitial Solutions I. Analysis of Interaction Parameters

AbstractThe pseudopotential method is used to calculate first‐ and second‐order interaction parameters in f.c.c. and h.c.p. interstitial solutions of aluminium and magnesium alloys. Values calculated of interaction parameters are used for an estimation of the series convergence for the logarithm of the boron and carbon activity coefficient. The results show that the series convergence depends, to a great extent, on the selection of the alloying element and its concentration.