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Boric acid

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https://www.readbyqxmd.com/read/28342883/kinetic-and-mechanistic-study-of-the-ph-dependent-activation-epoxidation-of-prodrug-treosulfan-including-the-reaction-inhibition-in-a-borate-buffer
#1
Michał Romański, Whitney Ratajczak, Franciszek Główka
A prodrug treosulfan (T) undergoes a pH-dependent activation to epoxide derivatives. The process seems to involve an intramolecular Williamson reaction (IWR) but clear kinetic evidence is lacking. Moreover, a cis-diol system present in the T structure is expected to promote complexation with boric acid. As a result, the prodrug epoxidation would be inhibited, however this phenomenon has not been investigated. In this paper, the effect of pH on the kinetics of T conversion to its monoepoxide was studied from a mechanistic point of view...
March 22, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28334270/development-of-diagnostic-insecticide-concentrations-and-assessment-of-insecticide-susceptibility-in-german-cockroach-dictyoptera-blattellidae-field-strains-collected-from-public-housing
#2
Mahsa Fardisi, Ameya D Gondhalekar, Michael E Scharf
Insecticide resistance in German cockroaches (Blattella germanica (L.)) has been a barrier to effective control since its first documentation in the 1950s. A necessary first step toward managing resistance is to understand insecticide susceptibility profiles in field-collected strains so that active ingredients (AIs) with lowest resistance levels can be identified. As a first step in this study, diagnostic concentrations (DCs) were determined for 14 insecticide AIs based on lethal concentrations that killed 99% or 90% of the individuals from a susceptible lab strain (JWax-S)...
March 20, 2017: Journal of Economic Entomology
https://www.readbyqxmd.com/read/28318942/cyclic-mu-opioid-receptor-ligands-containing-multiple-n-methylated-amino-acid-residues
#3
Anna Adamska-Bartłomiejczyk, Anna Janecka, Márton Richárd Szabó, Maria Camilla Cerlesi, Girolamo Calo, Alicja Kluczyk, Csaba Tömböly, Attila Borics
In this study we report the in vitro activities of four cyclic opioid peptides with various sequence length/macrocycle size and N-methylamino acid residue content. N-Methylated amino acids were incorporated and cyclization was employed to enhance conformational rigidity to various extent. The effect of such modifications on ligand structure and binding properties were studied. The pentapeptide containing one endocyclic and one exocyclic N-methylated amino acid displayed the highest affinity to the mu-opioid receptor...
March 7, 2017: Bioorganic & Medicinal Chemistry Letters
https://www.readbyqxmd.com/read/28314961/ecotoxicity-of-boric-acid-in-standard-laboratory-tests-with-plants-and-soil-organisms
#4
REVIEW
Juliska Princz, Leonie Becker, Adam Scheffczyk, Gladys Stephenson, Rick Scroggins, Thomas Moser, Jörg Römbke
To verify the continuous sensitivity of ecotoxicological tests (mainly the test organisms), reference substances with known toxicity are regularly tested. Ideally, this substance(s) would lack specificity in its mode action, be bioavailable and readily attainable with cost-effective means of chemical characterization. Boric acid has satisfied these criteria, but has most recently been characterized as a substance of very high concern, due to reproductive effects in humans, thus limiting its recommendation as an ideal reference toxicant...
March 17, 2017: Ecotoxicology
https://www.readbyqxmd.com/read/28304112/evaluation-of-various-approaches-to-the-isolation-of-steroid-hormones-from-urine-samples-prior-to-fass-mekc-analysis
#5
Ilona Olędzka, Piotr Kowalski, Alina Plenis, Tomasz Bączek
The goal of this study was to assess various analytical approaches for the simultaneous and efficient extraction of steroid hormones (cortisone, cortisol, prednisolone, corticosterone, testosterone, 17α-methyltestosterone, epitestosterone, progesterone) from urine samples prior to separation based on field-amplified sample stacking-micellar electrokinetic chromatography (FASS-MEKC). FASS-MEKC successfully allowed the compounds to be separated within 12 min using a background electrolyte (BGE) comprised of 5 mM sodium tetraborate, 150 mM boric acid, 50 mM SDS and 15% methanol...
March 17, 2017: Electrophoresis
https://www.readbyqxmd.com/read/28300266/boric-acid-destabilized-lithium-borohydride-with-a-5-6-wt-dehydrogenation-capacity-at-moderate-temperatures
#6
Yong Wu, Xiaojing Jiang, Jun Chen, Yue Qi, Yuxuan Zhang, He Fu, Jie Zheng, Xingguo Li
Boric acid effectively promotes the dehydrogenation of lithium borohydride due to the interactions between protonic and hydridic hydrogen. The simple mixture of LiBH4-(4/3)B(OH)3 can release 5.6 wt% hydrogen below 180 °C with only a trace amount of water, thus constituting a highly attractive single-use hydrogen storage material.
March 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28285642/a-new-hope-for-obesity-management-boron-inhibits-adipogenesis-in-progenitor-cells-through-the-wnt-%C3%AE-catenin-pathway
#7
Ayşegül Doğan, Selami Demirci, Hüseyin Apdik, Omer Faruk Bayrak, Sukru Gulluoglu, Emre Can Tuysuz, Oleg Gusev, Albert A Rizvanov, Emrah Nikerel, Fikrettin Şahin
Obesity is a worldwide medical problem resulting in serious morbidity and mortality involving differentiation of pre-adipocytes into mature adipocytes (adipogenesis). Boron treatment has been reported to be associated with weight reduction in experimental animals; however, its effects on pre-adipocyte differentiation and anti-adipogenic molecular mechanisms are unknown. In this study, we demonstrate the inhibitory activities of boric acid (BA) and sodium pentaborate pentahydrate (NaB) on adipogenesis using common cellular models...
April 2017: Metabolism: Clinical and Experimental
https://www.readbyqxmd.com/read/28279171/single-amino-acid-substitutions-in-the-selectivity-filter-render-nbxip1-1%C3%AE-aquaporin-water-permeable
#8
Henry Ampah-Korsah, Yonathan Sonntag, Angelica Engfors, Andreas Kirscht, Per Kjellbom, Urban Johanson
BACKGROUND: Aquaporins (AQPs) are integral membrane proteins that facilitate transport of water and/or other small neutral solutes across membranes in all forms of life. The X Intrinsic Proteins (XIPs) are the most recently recognized and the least characterized aquaporin subfamily in higher plants. XIP1s have been shown to be impermeable to water but permeable to boric acid, glycerol, hydrogen peroxide and urea. However, uncertainty regarding the determinants for selectivity and lack of an activity that is easy to quantify have hindered functional investigations...
March 9, 2017: BMC Plant Biology
https://www.readbyqxmd.com/read/28266843/spectroscopic-studies-of-the-chan-lam-amination-a-mechanism-inspired-solution-to-boronic-ester-reactivity
#9
Julien C Vantourout, Haralampos N Miras, Albert Isidro-Llobet, Stephen Sproules, Allan J B Watson
We report an investigation of the Chan-Lam amination reaction. A combination of spectroscopy, computational modeling, and crystallography has identified the structures of key intermediates and allowed a complete mechanistic description to be presented, including off-cycle inhibitory processes, the source of amine and organoboron reactivity issues, and the origin of competing oxidation/protodeboronation side reactions. Identification of key mechanistic events has allowed the development of a simple solution to these issues: manipulating Cu(I) → Cu(II) oxidation and exploiting three synergistic roles of boric acid has allowed the development of a general catalytic Chan-Lam amination, overcoming long-standing and unsolved amine and organoboron limitations of this valuable transformation...
March 24, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28252208/a-fluorescence-based-assay-for-in%C3%A2-vitro-screening-of-saprolegnia-inhibitors
#10
S E Ali, I Skaar
The incidence of fish pathogenic oomycetes, Saprolegnia, has increased significantly in aquaculture since the ban of malachite green. For the efficient characterization of anti-Saprolegnia therapeutics, simple accurate methods are required. However, the current screening methods are limited by time, and none of them are confirming the viability of treated spores or hyphae. In this study, a modified fluorescence-based assay for the in vitro screening of Saprolegnia inhibitors has been developed. This method involves the use of FUN-1 viability dye combined with calcofluor white M2R, and is based on the formation of orange-red cylindrical intravacuolar structures (CIVS) in metabolically active spores, hyphae and biofilms...
March 2, 2017: Journal of Fish Diseases
https://www.readbyqxmd.com/read/28249480/a-source-to-deliver-mesoscopic-particles-for-laser-plasma-studies
#11
R Gopal, R Kumar, M Anand, A Kulkarni, D P Singh, S R Krishnan, V Sharma, M Krishnamurthy
Intense ultrashort laser produced plasmas are a source for high brightness, short burst of X-rays, electrons, and high energy ions. Laser energy absorption and its disbursement strongly depend on the laser parameters and also on the initial size and shape of the target. The ability to change the shape, size, and material composition of the matter that absorbs light is of paramount importance not only from a fundamental physics point of view but also for potentially developing laser plasma sources tailored for specific applications...
February 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28248430/reconstitution-of-vanadium-haloperoxidase-s-catalytic-activity-by-boric-acid-towards-a-potential-biocatalytic-role-of-boron
#12
Filipe Natalio, Stefanie Wiese, Wolfgang Brandt, Ludger Wessjohann
Boron's unusual properties inspired major advances in chemistry. In Nature, the existence and importance of boron has been fairly explored (e.g. bacterial signaling, plant development) but its role as biological catalyst was never reported. Here, we show that boric acid [B(OH)3] can restore chloroperoxidase activity of Curvularia inaequalis recombinant apo-haloperoxidase's (HPO) in the presence of hydrogen peroxide and chloride ions. Molecular modeling and semi-empirical PM7 calculations support a thermodynamically highly favored (bio)catalytic mechanism similarly to vanadium haloperoxidases (V-HPO) in which [B(OH)3] is assumedly located in apo-HPO's active site and a monoperoxyborate [B(OH)3(OOH)-] intermediate is formed and stabilized by interaction with specific active site amino acids leading ultimately to the formation of HOCl...
March 1, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28208304/boric-acid-functional-lanthanide-metal-organic-frameworks-for-selective-ratiometric-fluorescence-detection-of-fluoride-ions
#13
Zhong-Rui Yang, Man-Man Wang, Xue-Sheng Wang, Xue-Bo Yin
Here, we report that boric acid is used to tune the optical properties of lanthanide metal-organic frameworks (LMOFs) for dual-fluorescence emission and improves the selectivity of LMOFs for the determination of F(-) ions. The LMOFs are prepared with 5-boronoisophthalic acid (5-bop) and Eu(3+) ions as the precursors. Emission mechanism study indicates that 5-bop is excited with UV photons to produce its triplet state, which then excites Eu(3+) ions for their red emission. This is the general story of the antenna effect, but electron-deficient boric acid decreases the energy transfer efficiency from the triplet state of 5-bop to Eu(3+) ions, so dual emission from both 5-bop and Eu(3+) ions is efficiently excited at the single excitation of 275 nm...
February 7, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28206859/evaluation-and-adaptation-of-attractive-toxic-sugar-baits-for-culex-tarsalis-and-culex-quinquefasciatus-control-in-the-coachella-valley-southern-california
#14
Whitney A Qualls, Jodi Scott-Fiorenzano, Gunter C Müller, Kristopher L Arheart, John C Beier, Rui-De Xue
The project goal was to determine how a new vector control strategy that targets the sugar-feeding behavior of mosquitoes, attractive toxic sugar baits (ATSBs), can be used to more effectively control West Nile virus (WNV) vectors in the Coachella Valley, California. Three laboratory studies were conducted to determine the utility of this method for control against Culex quinquefasciatus and Culex tarsalis : 1) efficacy evaluations of 2 formulations of ATSB, microencapsulated garlic oil, and a combination of microencapsulated garlic oil and 1% boric acid; 2) choice assays to determine the attractiveness of ATSB with the microencapsulated garlic oil against attractive sugar baits (ASB; the attractant alone; without toxin) and a 10% sucrose solution; and 3) vegetation efficacy tests on 3 common plant species in the Coachella Valley, Atriplex lentiformis, Tamarix ramosissima , and Pluchea sericea...
December 2016: Journal of the American Mosquito Control Association
https://www.readbyqxmd.com/read/28195399/capillary-electrophoresis-fingerprints-combined-with-chemometric-methods-to-evaluate-the-quality-consistency-and-predict-the-antioxidant-activity-of-yinqiaojiedu-tablet
#15
Didi Ma, Lanping Yang, Bo Yan, Guoxiang Sun
The quality consistency of Yinqiaojiedu tablets was monitored by extracting their electrophoretic fingerprint and marker compound data which were obtained using capillary electrophoresis. To select the suitable background electrolyte, wing-shape method was proposed. A background electrolyte composed of 103.1 mM boric acid, 51.6 mM sodium borate, 9.8 mM disodium hydrogen phosphate, and 15.6 mM sodium dihydrogen phosphate was used to separate compounds. Under the optimized background electrolyte, the content of three marker compounds was determined in 25 Yinqiaojiedu tablet samples...
February 14, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28167234/epiberberine-a-natural-protoberberine-alkaloid-inhibits-urease-of-helicobacter-pylori-and-jack-bean-susceptibility-and-mechanism
#16
Lihua Tan, Cailan Li, Hanbin Chen, Zhizhun Mo, Jiangtao Zhou, Yuhong Liu, Zhilin Ma, Yuyao Xu, Xiaobo Yang, Jianhui Xie, Ziren Su
In our previous study, Rhizoma Coptidis extract was found to exert more potent inhibitory effect than its major component berberine towards urease from Helicobacter pylori (HPU) and jack bean (JBU). In continuation of our work, the present study was designed to further comparatively investigate the urease inhibitory activities of five major protoberberine alkaloids in Rhizoma Coptidis, namely berberine, palmatine, coptisine, epiberberine, jateorhizine to identify the bioactive constituent, and illuminate the potential mechanism of action...
February 4, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28163341/complexation-of-nickel-ions-by-boric-acid-or-poly-borates
#17
REVIEW
Anais Graff, Etienne Barrez, Philippe Baranek, Martin Bachet, Pascale Bénézeth
An experiment based on electrochemical reactions and pH monitoring was performed in which nickel ions were gradually formed by oxidation of a nickel metal electrode in a solution of boric acid. Based on the experimental results and aqueous speciation modeling, the evolution of pH showed the existence of significant nickel-boron complexation. A triborate nickel complex was postulated at high boric acid concentrations when polyborates are present, and the equilibrium constants were determined at 25, 50 and 70 °C...
2017: Journal of Solution Chemistry
https://www.readbyqxmd.com/read/28158885/breaking-bad-delirium-methamphetamine-and-boric-acid-toxicity-with-hallucinations-and-pseudosepsis
#18
Kayla Johnson, Joanna L Stollings, E Wesley Ely
OBJECTIVES: A 30-year-old patient presented with hallucinations and profound shock. He was initially misdiagnosed as having severe sepsis; once ingestions were considered, he was diagnosed as potentially having arsenic toxicity. SUMMARY: The clinical story reveals many instructional lessons that could aid in the evaluation and management of future patients. This man presented with large amounts of blue crystals around his nose and lips from inhaling and eating boric acid (an ant poison) so he could, as he put it, kill the ants "pouring into my mouth and nose and up into my brain...
February 2017: Southern Medical Journal
https://www.readbyqxmd.com/read/28126655/direct-solid-surface-fluorescence-spectroscopy-of-standard-chemicals-and-humic-acid-in-ternary-system
#19
S Mounier, G Nicolodelli, R Redon, D M B P Milori
The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid...
April 15, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28124897/facile-modification-of-reverse-osmosis-membranes-by-surfactant-assisted-acrylate-grafting-for-enhanced-selectivity
#20
Katie Baransi-Karkaby, Maria Bass, Stanislav Levchenko, Shahar Eitan, Viatcheslav Freger
The top polyamide layer of composite reverse osmosis (RO) membranes has a fascinatingly complex structure, yet nanoscale nonuniformities inherently present in polyamide layer may reduce selectivity, e.g., for boron rejection. This study examines improving selectivity by in situ "caulking" such nonuniformities using concentration polarization-enhanced graft-polymerization with a surfactant added to the reactive solution. The surfactant appears to enhance both polarization (via monomer solubilization in surfactant micelles) and adherence of graft-polymer to the membrane surface, which facilitates grafting and reduces monomer consumption...
February 10, 2017: Environmental Science & Technology
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