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PubMed1990

Effects of dietary borate and aluminate on riboflavin metabolism in the breeding hen.

Breeding hens were used to investigate the effects of aluminate and borate ingestion on riboflavin metabolism. Groups of six hens were fed on either a control diet, or the control diet plus 15 g kg-1 of either sodium metaborate or sodium meta-aluminate. All diets contained 6 mg kg-1 riboflavin. Daily egg production per hen in the borate group had mean values of 0.71, 0.21 and 0.02 for the three weeks of the study. The values were 0.91, 0.91, 0.86 and 0.86, 0.74, 0.89 for the control and aluminate groups, respectively. Fertility (fertile eggs per 100 set) and hatchability (live chicks per 100 fertile eggs) were both nil in the borate-treated hens, compared with 57 and 95 and 59 and 100 for the control and aluminate-treated hens, respectively. Fluorimetric analysis of blood plasma, egg yolk and albumen showed that the riboflavin contents of all tissues were greatly reduced in the borate-treated hens. Borate ingestion can therefore induce a severe riboflavin deficiency in the hen, but aluminium, a more universal contaminant of food or water, did not impair riboflavin metabolism when fed as aluminate.

Aluminum↗
PubMed2000

The greater negative charge density of DNA in tris-borate buffers does not enhance DNA condensation by multivalent cations.

As indicated by recent measurements of the electrophoretic free solution mobility, DNA appears to have a greater helical charge density in Tris-borate-EDTA (TBE) buffers than in Tris-acetate-EDTA (TAE) buffers. Since electrostatic forces play a major role in DNA packaging processes, we have investigated the condensation of closed circular plasmid DNA using total intensity and dynamic light scattering in Tris-borate, Tris-acetate, and Tris-cacodylate buffers with cobaltic hexa-amine (III) [Co(NH(3))(3+)(6)]. We find that neither the critical concentration of Co(NH(3))(3+)(6) nor the hydrodynamic radii of the resulting condensates vary significantly in the buffer systems studied here despite the prediction that DNA condensation should occur at significantly lower Co(NH(3))(3+)(6) concentrations in Tris-borate buffers. Assuming a persistence length behavior similar to B-DNA in the presence of multivalent cations, a decrease in the attractive counterion correlation pressure decay length in Tris-borate buffers does not account for our observations. It is possible that the binding of multivalent cations to DNA may hinder borate association with the DNA double helix.

Amines↗
PubMed2005

Cyano- and isocyanotris(trifluoromethyl)borates: syntheses, spectroscopic properties, and solid state structures of K[(CF3)3BCN] and K[(CF3)3BNC].

A two step synthesis to the isocyanotris(trifluoromethyl)borate anion, [(CF3)3BNC]-, and its isomerization to the cyanotris(trifluoromethyl)borate anion, [(CF3)3BCN]-, at temperatures above 150 degrees C are presented. In the first step (CF3)3BNCH was obtained by reacting (CF3)3BCO with hydrogen cyanide followed by deprotonation of the HCN adduct with Li[N(SiMe3)2] in toluene. The thermal behavior of K[(CF3)3BNC] and K[(CF3)3BCN] were investigated by differential scanning calorimetry (DSC), and K[BF4] was identified as a major solid decomposition product. The enthalpy of the isocyanide-cyanide rearrangement, deltaH(iso) = -35 +/- 4 kJ mol(-1), was obtained from DSC measurements, and the activation energy, E(a) = 180 +/- 20 kJ mol(-1), from kinetic measurements. The isomerization was modeled as an intramolecular reaction employing DFT calculations at the B3LYP/6-311+G(d) level of theory yielding a reaction enthalpy of deltaH(iso) = -36.1 kJ mol(-1) and an activation energy of E(a) = 155.7 kJ mol(-1). The solid-state structures of K[(CF3)3BNC] and K[(CF3)3BCN] were determined by single-crystal X-ray diffraction. Both salts are isostructural and crystallize in the orthorhombic space group Pnma (no. 62). In the crystals the borate anions possess C(s) symmetry, while for the energetic minimum C3 symmetry is predicted by DFT calculations. The borate anions have been characterized by IR and Raman spectroscopy as well as by NMR spectroscopy. The assignment of the IR and Raman bands is supported by their calculated wavenumbers and intensities. The spectroscopic and structural properties of both borate anions are compared to the properties of the isoelectronic borane carbonyl (CF3)3BCO and the [B(CF3)4]- anion as well as to those of other related species.

Journal Article↗
PubMed2005

Surfactant quaternary ammonium hydrotris(1-pyrazolyl)borates.

Quaternary ammonium surfactants with the hydrotris(1-pyrazolyl)borate anion as an unusual counterion were prepared and characterized. Dodecyl- (1a), tetradecyl- (1b), and hexadecyltrimethylammonium hydrotris(1-pyrazolyl)borate (1c), as well as didodecyldimethylammonium hydrotris(1-pyrazolyl)borate (2), were prepared by metathesis reactions with the corresponding quaternary ammonium bromides and potassium hydrotris(1-pyrazolyl)borate (4). Although the surfactants have limited stabilities in water at 23 degrees C, they were characterized by measurement of their Krafft temperatures and critical aggregation concentrations. (1)H NMR spectroscopy suggested that the single-chain surfactants 1 form small aggregates in water and revealed an association of the quaternary ammonium and hydrotris(1-pyrazolyl)borate ions above their critical aggregation concentrations. Cryo-etch high-resolution scanning electron microscopy indicated that 1a and 1b most likely form segregation patterns upon plunge-freezing and cryo-etching of their aqueous solutions, and a single-crystal X-ray diffraction study of 1a was performed.

Journal Article↗
PubMed2006

Cage-shaped borate esters with enhanced Lewis acidity and catalytic activity.

[structure: see text] A cage shape causes high Lewis acidity and catalytic activity on boron. Borate esters that have cage-shaped ligands have accessible LUMO with lower eigenvalues than normal open-shaped borate esters. A large dihedral angle at C-O-B-O in cage-shaped borate esters induces less overlap between p-orbitals on O and B. The hetero-Diels-Alder reaction is effectively catalyzed by the cage-shaped borate, although the open-shaped borate does not act as a catalyst.

Journal Article↗
PubMed2004

Gold derivatives of scorpionates: comparison with the other coinage metal poly(pyrazolyl)borate analogues.

Gold derivatives [Au(Tpx)(PR3)](Tpx = Tp, hydrotris(pyrazol-1-yl)borate or Tp*, hydrotris(3,5-dimethylpyrazol-1-yl)borate; R = Ph or tBu) and [Au(pzTp)(PR3)x](pzTp = tetrakis(pyrazol-1-yl)borate, x = 1 or 2, R = Ph or tBu) have been synthesised and characterized both in solution (1H- and 31P[1H]-NMR) and in the solid state (IR, single crystal X-ray structure analysis, 31P CPMAS). 31P [1H] NMR solution data suggest greater stability of the tetrakis(pyrazolyl)borate relative to those of tris(pyrazolyl)borate. All compounds are fluxional at room temperature. In order to compare [Au(Tp*)(PPh3)] with analogous coinage metal adducts we have synthesized and structurally characterized [Cu(Tp*)(PPh3)] x PPh3 and [Ag(Tp*)(PPh3)] x 2MeCN. In [Au(Tp*)(PPh3)] the gold atom adopts a distorted tetrahedral geometry with 2.181(5) and 2.37(2) angstroms (cf. 2.166(6), 2.098(1) in [Cu(Tp*)PPh3], 2.156(2), 2.075(7) in [Cu(Tp*)(PPh3)] x PPh3; and in [Ag(Tp*)PPh3] x MeCN 2.347(12), 2.35(5) angstroms). There are three independent [Au(Tp*)(PPh3)] molecules in the asymmetric unit of the structure with their PAu...B axes lying on the cell diagonal of a cubic P213 cell, two with the same chirality aligned opposed in direction to the third which is of opposite chirality. A number of Cu, Ag and Au complexes containing scorpionate ligands have also been investigated by 31P cross-polarization magic-angle-spinning (CPMAS) NMR spectroscopy.

Journal Article↗
PubMed1990

Nonamphoteric isoelectric focusing: II. Stability of borate-glycerol pH gradients in recycling isoelectric focusing.

By complexing polyols with borate in recycling isoelectric focusing and by varying the ratio of polyol to borate over the useful pH range of 4.0-6.0, it is possible to control pH. Twelve solutions of 0.1 M boric acid and varying glycerol concentration were used to vary pH in a twelve-compartment commercial recycling isoelectric focusing (RIEF) system. Various concentrations of boric acid were tested as anolyte, and various Tris(hydroxymethylamino)methane-borate buffer systems were tested as catholyte. Electroosmosis, hydrogen ion flow, and fluid balancing were characterized in two glycerol gradients; one was maintained at 0.06 pH/fraction and the other at 0.12 pH/fraction. In the latter case, ovalbumin (pI4.70) migrated to the pH 4.61 and 4.72 compartments. It is concluded that the borate-glycerol system can be adequately stabilized in RIEF for isoelectric purification of certain proteins.

Borates↗
PubMed2004

Importance of the counterion in optimization of a borate electrolyte system for analyses of anions in samples with complex matrices performed by capillary zone electrophoresis.

Borate buffers are common background electrolytes for analyses of anions in capillary zone electrophoresis. Usually, sodium borate at a given pH is used and this specification seems to be sufficient for a successful analysis. In this paper, we show that free migration of OH(-) may deteriorate the analysis of a typical anionic analysis of clinical samples due to uncontrolled migration of OH(-) throughout the systems of analyzed zones and may damage the stacking of anionic analytes of interest. We have proven that the use of ammonium borate may remedy the situation where the presence of ammonium may selectively stop the free migration of OH(-) ions, slow down their effective mobility and bring their safe behavior resulting in reproducible stacking of clinically important anions. Results of real analyses of human serum samples confirmed the proposed method and proved that substitution of sodium for ammonium in borate buffers offers reliable analyses of clinical samples having chloride as the bulk component. The experimental results given in this paper are supported also by computer simulation, which can not only support the positive results but also show the dynamics of the separation that is otherwise hidden to any detection possibilities.

Borates↗
PubMed1998

Measurement of borate in occupational environments.

The hydration stability for inhalable borate particles has been characterized as a function of temperature and relative humidity when collected by a field personnel monitor. The rate of hydration was measured for boric acid (B[OH]3); Neobor borax 5 mol (Na2O x 2B2O3 x 5H2O); borax 10 mol (Na2O x 2B2O3 x 10H2O); anhydrous boric acid (B2O3); and anhydrous borax (Na2O x 2B2O3). The particle size is large in bulk commercial products, such that they can be handled and stored without problems. However, inhalable dust particles, in the range of 20 microm (MMD), undergo hydration/dehydration rapidly owing to their high surface-to-volume ratio. The hydration state of a collected air sample was found to be strongly dependent on the conditions of relative humidity and temperature during its collection. As a consequence, the actual chemical species of dust being inspired cannot be identified accurately. Inhalable particles of borax 10 mol placed in a field personal monitoring cartridge and exposed to dry air at 2.0 L/min at 70 degrees F for 7 h undergo rapid dehydration, producing a sodium borate residue having significantly less than four waters of hydration. Likewise, inhalable particles of anhydrous boric acid and anhydrous borax were found to hydrate under normal atmospheric conditions. Borax 5 mol and boric acid were found to be stable to dehydration. In most cases, the specific borate species or borate compounds collected in a field monitor cannot be accurately characterized other than by their boron (B) content.

Borates↗
PubMed1994

The structure and (local) stability constants of borate esters of mono- and di-saccharides as studied by 11B and 13C NMR spectroscopy.

The formation of borate esters of various mono- and di-saccharides in aqueous solution was studied by 11B and 13C NMR spectroscopy. Association constants K(B-L) at a carbohydrate-borate molar ratio of 1:1, pH 7, and 25 degrees C were determined and compared with literature values obtained from potentiometry. The association constants K(B-L) were converted into local association constants Kloc(B-L) by using the distribution of the various anomeric forms in D2O. In this way, values of Kloc(B-L) were obtained, which appear to be characteristic of the configuration concerned. They explain the favourable effect of borate in the alkaline isomerisation of lactose into lactulose. At a low molar ratio (1:3) of carbohydrate-borate, predominantly diborate esters (B-)2L were formed.

Borates↗
PubMed1995

Treatment of cells with alkaline borate buffer extends the capability of interphase FISH mapping.

Interphase fluorescence in situ hybridization (FISH) has been shown to be a means to map DNA sequences relative to each other in the 100 kb to 1-2 Mb genomic-separation range. At distances below 0.1 Mb, probe sites are infrequently resolved in interphase chromatin. In the 0.1- to 1-Mb range, interphase chromatin can be modeled as a freely flexible chain. The mean square interphase distance between two probes is proportional to the genomic separation between the probes on the linear DNA molecule. Above 1-2 Mb, the relationship between interphase distance and genomic separation changes abruptly and appears to level off. We have used alkaline-borate treatment to expand the capability of interphase FISH mapping. We show here that alkaline-borate treatment increases nuclear diameter, the interphase distance between probes on homologous chromosomes, and the distance between probes on the same chromosome. We also show that the mean square distance between hybridization sites in borate-treated nuclei is proportional to genomic separation up to 4 Mb. Thus, alkaline-borate treatment enhances the capability of interphase FISH mapping by increasing the absolute distance between probes and extending the range of the simple relationship between interphase distance and genomic separation.

Borates↗
PubMed2006

Simultaneous determination of bioactive flavone derivatives in Chinese herb extraction by capillary electrophoresis used different electrolyte systems--borate and ionic liquids.

In this paper, novel capillary electrophoresis (CE) methods, which used ionic liquids (1-ethyl-3-methylimidazoium tetrafluoroborate, 1-butyl-3-methylimidazoium tetrafluoroborate), were established to separate and determine some bioactive flavone derivatives in Chinese herb Seriphidium santolinum (Schrenk) Poljak. In order to investigate the traits of ionic liquids in CE, borate was also used as electrolyte to compare with. And the excellence of CE, which used ionic liquids as main running electrolyte and beta-cyclodextrin (beta-CD) as modifier, was illuminated as well. As a result of the study, the difference of ionic liquids and borate in CE was discussed and the advantage of CE, which used ionic liquids as electrolytes for separation, was shown. The analysis was obtained within short time (5-6 min). From the result, it was found that the system, which used ionic liquids, was robust because the joule heating was small. The method of CE, which used ionic liquids, has lower detection limits (0.137-0.642 microg/mL) than that of borate (0.762-1.036 microg/mL). And the CE, which used ionic liquids method, has lower limit of linear range (1.100-2.656 microg/mL), while that of CE, which used borate method, was 2.188-5.313 microg/mL.

Asteraceae↗
PubMed2000

A combined X-ray and NMR study of borate esters of furanoidic cis-1,2-diols.

Crystals of K[B(AnErytH(-2)2] x 2 H2O (AnEryt = 1,4-anhydroerythritol) form from aqueous alkaline solutions containing a double molar amount of diol over borate. The spiro-type monoanions are the main borate species in the mother liquors of crystallisation according to 11B and 13C NMR spectroscopy. Ribofuranosides form analogous borate esters using their 1,4-anhydroerythritol core. Crystals of Na[B(Me beta-D-Ribf 2,3H(-2))2] x 2 H2O were grown from alkaline methyl beta-D-ribofuranoside solutions that had attacked boron-containing Duran vessels. NMR spectra show closely resembling borate-ester speciation in solutions of diols with the 1,4-anhydroerythritol core--1,4-anhydroerythritol itself, methyl beta-D-ribofuranoside and guanosine.

Borates↗
PubMed1998

Stabilization of lactate dehydrogenase following freeze thawing and vacuum-drying in the presence of trehalose and borate.

PURPOSE: The purpose of this work was to investigate the effects of trehalose and trehalose/sodium tetraborate mixtures on recovery of lactate dehydrogenase (LDH) activity following freeze-thawing and centrifugal vacuum-drying/rehydration. The storage stability of LDH under conditions of either high relative humidity or high temperature was also studied. METHODS: LDH was prepared in buffered aqueous formulations containing trehalose alone and trehalose/"borate" mixtures. Enzymatic activity was measured immediately following freeze-thawing and vacuum-drying/rehydration processes, and also after vacuum-dried formulations were stored in either high humidity or high temperature environments. Also, glass transition temperatures (Tg) were measured for both freeze-dried and vacuum-dried formulations. RESULTS: The Tg values of freeze-dried trehalose/borate mixtures are considerably higher than that of trehalose alone. Freezing and vacuum-drying LDH in the presence of 300 mM trehalose resulted in the recovery of 80% and 65% of the original activity, respectively. For vacuum-dried mixtures, boron concentrations below 1.2 mole boron/ mole trehalose had no effect on recovered LDH. After several weeks storage in either humid (100% relative humidity) or warm (45 degrees C) environments, vacuum-dried formulations that included trehalose and borate showed greater enzymatic activities than those prepared with trehalose alone. We attribute this stability to the formation of a chemical complex between trehalose and borate. CONCLUSIONS: The high Tg values of trehalose/borate mixtures offer several advantages over the use of trehalose alone. Most notable is the storage stability under conditions of high temperature and high relative humidity. In these cases, formulations that contain trehalose and borate are superior to those containing trehalose alone. These results have practical implications for long-term storage of biological materials.

Borates↗
PubMed1976

A TLD system based on lithium borate for the measurement of doses to patients undergoing medical irradiation.

A dosimetry system has been developed which is especially suited to the measurement of doses to patients undergoing irradiation for medical purposes. It is a TLD system based on lithium borate which has been used both in powder form and made up into solid discs by incorporation within PTFE. The predominant advantages of this material over other more widely used TLD materials are its closer approximation to soft tissue, its simple glow curve which eliminates the need for complicated annealing procedures and its low cost. The luminescence from the lithium borate is measured with a specially designed reader which uses radiofrequency heating. At present, using lithium borate powder, the system is capable of measuring doses down to 10 mrad and using lithium borate/PTFE discs it can measure down to 50 mrad with adequate precision. Preliminary measurements on solid glassy discs of lithium borate suggest that this form of the material may in some respects be superior for patient dosimetry.

Borates↗
PubMed2003

Use of borate to control the 5'-position-selective microbial glucosylation of pyridoxine.

Nearly 100% 5'-position selectivity of transglucosylation from maltodextrin to pyridoxine (PN) by cells of Verticillium dahliae TPU 4900 was observed when the reaction was carried out with borate. The same effect of borate was observed not only during synthesis of pyridoxine 5'-alpha-D-glucoside by partially purified enzyme of this strain but also during synthesis of this compound by other microorganisms and with other enzymes (alpha-glucosidase and cyclomaltodextrin glucanotransferase). The effect was thought to be caused by the formation of a borate complex with 3- and 4'-position hydroxyl groups of PN. A decrease in the formation of pyridoxine 5'-alpha-D-glucoside was observed in the reaction with borate, but this decrease was overcome by optimizing the pH and increasing the amount of cells in the reaction mixture.

Borates↗
PubMed1992

Dose related acute irritant symptom responses to occupational exposure to sodium borate dusts.

A repeated measurement design was employed in the study of acute symptoms of eye and respiratory tract irritation resulting from occupational exposure to sodium borate dusts. The symptom assessment of the 79 exposed and 27 unexposed subjects comprised interviews before the shift began and then at regular hourly intervals for the next six hours of the shift, four days in a row. Exposures were monitored concurrently with a personal real time aerosol monitor. Two different exposure profiles, a daily average and short term (15 minute) average, were used in the analysis. Exposure-response relations were evaluated by linking incidence rates for each symptom with categories of exposure. Acute incidence rates for nasal, eye, and throat irritation, and coughing and breathlessness were found to be associated with increased exposure levels of both exposure indices. Steeper exposure-response slopes were seen when short term exposure concentrations were used. Results from multivariate logistic regression analysis suggest that current smokers tended to be less sensitive to the exposure to airborne sodium borate dust. There was no indication that anhydrous sodium borate was more potent than the other sodium borates in this work environment.

Adult↗
PubMedDate not supplied

Efficacy of sodium borate in the prevention of fatty liver in dairy cows.

The effects of sodium borate (100 mg/kg body weight, p.o., 15 days) from a month before expected calving until a month after calving were evaluated in dairy cows susceptible to fatty liver. Cows received either sodium borate (n = 13) or no treatment (n = 10). All cows had mild fatty livers and increased plasma triglycerides and very low density lipoprotein (VLDL) concentrations at the beginning of the experiment. The control group of cows developed significant fatty liver after calving, and 2 of them had severe fatty liver associated with clinical and biochemical abnormalities. There were no clinicopathological signs related to sodium borate administration. Serum triglycerides and VLDL concentrations before calving decreased significantly at calving and after calving in controls, and they were within the normal range only after calving. There were significant alterations during the experiment in some hematological and chemical variables between groups, within period, but they were within the normal range. Unlike treated cows, serum triglycerides and VLDL concentrations correlated with liver fat content after calving in untreated cows. Our results document that sodium borate decreases the degree of fatty liver in dairy cows during early lactation.

Animals↗