Presence Of BP Research Articles

Indium oxide-black phosphorus composites for ultrasensitive nitrogen dioxide sensing at room temperature

In2O3 nanorods were successfully incorporated by different amount of multi-layer black phosphorus (m-BP), forming the hetero-structured BP-In2O3 composites. The structure, morphology and composition of the as-synthesized composites were characterized by X-ray diffraction (XRD), field-emission electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Interestingly, the environmental stability of BP can be notably improved by the introduction of In2O3. Moreover, NO2 sensing properties of BP-In2O3 composites were tested at room temperature (25 °C) with relative humidity of 30%. It is demonstrated that the sensor based on BP-In2O3 composites exhibits high response, lower detect limit, short response-recovery time and outstanding selectivity at room temperature. Such sensing behavior can be attributed to high adsorption capacity to NO2, large surface area, excellent carrier mobility of BP-In2O3 in presence of BP, as well as high concentration of chemisorbed oxygen on the In2O3 surface derived from electrons transfer from BP to In2O3.

Development of an odorous repellent against common voles (Microtus arvalis) in laboratory screening and subsequent enclosure trials

Common voles (Microtus arvalis) can cause severe crop damage in European agriculture and are usually managed with rodenticides. Population dynamics and behavioral studies question rodenticide effectiveness, and an ecologically based management is needed. A useful addition to such a toolbox could be repelling odor barriers along field margins minimizing migration of voles to crops. We screened 17 plant products and mammalian scents in T-maze trials to test their repelling effects. The most repelling compounds (carrot seed oil (CS), black pepper oil (BP), spruce needle oil (SN), benzaldehyde (BA), BA and BP in double concentration (dc), combinations of BP + BA and BP + CS) were tested further in enclosures. We measured in four populations how often voles crossed enclosure compartments through channels treated with a compound or without a compound. In addition, the amount of rolled oats eaten by voles near treated and untreated channels was compared. In enclosures, voles avoided significantly channels treated with BP (79% more crossings through the control channel) and BP (dc) (42%). Voles consumed significantly more rolled oats near control channels than in the presence of BP + CS (72% more feeding at control), CS (51%), BA (dc) (36%), BP (32%) and BA + BP (28%). This demonstrated for the first time that natural compounds can reduce uptake of a highly attractive food source in common voles under semi-natural conditions. BP + CS was the most successful feeding deterrent and has the potential to be included in an ecologically based management approach.

Zinc oxide-black phosphorus composites for ultrasensitive nitrogen dioxide sensing.

Multi-layer black phosphorus (m-BP) has been successfully incorporated in zinc oxide (ZnO) hollow spheres, thus forming hetero-structured ZnO-BP composites; a study performed on their properties reveals that the BP environmental stability can be significantly enhanced by the introduction of ZnO, and the sensors based on ZnO-BP composites exhibit high response, fast response behavior, outstanding selectivity, and ultralow detection limit of 1 ppb towards NO2 gas molecules. The ultrasensitive sensing performance is suggested to be due to the large surface area, excellent carrier mobility, and enhanced charge transfer of ZnO-BP in the presence of BP. Moreover, the mechanism of NO2 sensing with ZnO-BP is confirmed by the calculations obtained from the first-principle studies.

【Original Contribution】 Regulation of Phospholipid Protrusion in the Cell Sized Vesicleby Hydrophobic Bisphenol A

The regulation of the phospholipid protrusion, the vertical fluctuation at the surface of cell-sized vesicles (CSVs),was investigated by solution NMR in combination with the 1H–1H nuclear Overhauser effect (NOE) enhancementmeasurement. Using deuterated bisphenol A (BP–d) and palmitic acid (PA–d) as model hydrophobic components,we compared how the lipid protrusion is modulated by the presence of BP–d and PA–d in the fluid, soft CSV mem-brane. The phospholipid protrusion was suppressed by BP–d but not by PA–d, although both BP–d and PA–d werebound to the membrane. The contrasting effect of BP–d and PA–d on the protrusion motion is interpreted by the dif-ference in the mode of interaction between these substances and lipids in the membrane; rather hydrogen bondingthan van der Waals forces is the decisive parameter to regulate the phospholipid protrusion motion.

Poly-ε-caprolactone composite scaffolds for bone repair.

Synthetic biomaterials combined with cells and osteogenic factors represent a promising approach for the treatment of a number of orthopedic diseases, such as bone trauma and congenital malformations. To guarantee optimal biological properties, bone substitutes are prepared with a 3D structure and porosity grade functional to drive cell migration and proliferation, diffusion of factors, vascularization and cell waste expulsion. In this study, synthetic hydroxyapatite (HA) or rat bone extracellular matrix (BP) were examined in an effort to optimize the mechanical properties and osteogenic activity of poly-ε-caprolactone scaffolds prepared with alginate threads (PCL-AT). Using rabbit bone marrow-derived mesenchymal stem cells (rMSCs), the effects of PCL composite substrates on cell adhesion, growth and osteogenic differentiation were evaluated. Micro-CT analysis and scanning electron microscopy evidenced that porous PCL scaffolds containing HA or BP acquire a trabecular bone-like structure with interconnected pores homogenously distributed and are characterized by a pore diameter of approximately 10 µm (PCL-AT-BP) or ranging from 10 to 100 µm. Although the porosity grade of both PCL-AT-HA and PCL-AT-BP promoted optimal conditions for the cell growth of rMSCs at the early phase, the presence of BP was crucial to prolong the cell viability at the late phase. Moreover, a precocious expression of Runx2 (at 7 days) was observed in PCL-AT-BP in combination with osteogenic soluble factors suggesting that BP controls better than HA the osteogenic maturation process in bone substitutes.

Clinical diagnosis of propriospinal myoclonus is unreliable: An electrophysiologic study

Propriospinal myoclonus is a rare movement disorder that is hypothesized to arise from a spinal generator that transmits activity up and down the spinal cord via long propriospinal pathways. Polymyography is mandatory for the diagnosis, but the typical electrophysiological pattern described for propriospinal myoclonus has been also found in patients with psychogenic axial jerks, supported by the presence of a Bereitschaftspotential (BP; from German, "readiness potential," also called the premotor potential). We evaluated polymyographic findings in 65 patients referred to us with a clinical diagnosis of propriospinal myoclonus and also looked for the presence of the BP, as detected by jerk-locked back-averaging. At clinical reassessment by a movement disorder specialist, nearly one-half of the patients had clinical clues suggestive of a psychogenic cause of the jerks. Electrophysiological studies were carried out on all 65 patients. Polymyography findings revealed an incongruent electromyographic pattern for propriospinal myoclonus in 84.6% of patients and the presence of the BP in 86.1% of the entire cohort. When taking into account either the presence of BP and/or incongruence of polymyographic features, all patients, including the approximately 50% clinically diagnosed as organic propriospinal myoclonus by a movement disorder expert, had strong neurophysiological evidence for a psychogenic origin of their jerks. The clinical distinction of propriospinal myoclonus from psychogenic axial jerks is unreliable. This is the largest cohort of patients with axial jerks reported so far and we suggest that most of the patients with a clinical picture that clinically resembles propriospinal myoclonus are likely to be psychogenic.

Unusual Binding of a Potential Biomarker with Human Serum Albumin

This study investigates the specific binding of a potential biomarker, [2,2'-bipyridyl]-3,3'-diol (BP(OH)2), with human serum albumin (HSA). The binding of BP(OH)2 at the two primary drug-binding sites on HSA (Sudlow's sites I and II) is explored by a competitive-binding study and monitored by considering the green-light emission from its diketo tautomer. Warfarin is used as a marker for site I and dansyl-L-proline (DP) as a competitor for site II. Steady-state and time-resolved fluorescence measurements affirm that neither of Sudlow's sites is the binding locus of BP(OH)2. To gain an idea regarding the probable binding site of BP(OH)2, we perform molecular-docking studies, which reveal a close proximity of the probe to Trp-214 in subdomain IIA of HSA. Confirmation of this contention is achieved by studying the quenching of the fluorescence of Trp-214 in the presence of BP(OH)2. Moreover, static quenching seems to be responsible for the depletion of the fluorescence of Trp-214, as manifested by the invariance of the intrinsic fluorescence lifetime of Trp-214, as a function of the concentration of BP(OH)2. Based on displacement and quenching studies, supported by molecular docking, we propose that BP(OH)2 binds in a cleft that separates subdomains IIIA and IIB, which is in close proximity to Trp-214.

Surface modification of a UV curable acrylate coating: In situ introduction of hydrophobic properties

Two polyfunctional silanes polymethyl-hydrosiloxane ( I) and octakis(dimethylsiloxy)-T8-silsequioxane ( II) are proposed as new co-initiators for radical acrylate photopolymerization reactions. In the presence of a type II photoinitiator such as benzophenone, isopropylthioxanthone or camphorquinone, these compounds are found reactive. The influence of oxygen is also examined. Incorporating only 1% (w/w) of I into an epoxy acrylate matrix allows the formation, under air, of a coating exhibiting a hydrophobic surface. In free radical promoted cationic polymerization, the addition of I to a BP/Φ 2I + system significantly enhances, under air, both the polymerization rate and the final conversion. The autoxidation reaction of I in the presence of BP under air generates a hydrophobic polymer surface. The reaction mechanisms are discussed on the basis of laser flash photolysis experiments.

Tetrahymena cells and the quantitative two‐phase assay: visual assessment of chemokinesis and gravikinesis

A two‐phase assay was used to assess chemokinesis and gravikinesis of Tetrahymena cells. METHOD: Tetrahymena thermophila cells were cultured without stirring at 36°C in a medium containing proteose peptone, yeast extract, glucose, and MOPS. Growing cells or cells in the stationary phase (1 million cells/ml) were used. Before assay, the cells were diluted 1+1. A semi‐microcuvette contained a 1‐ml bottom‐phase with NycoPrep™ Universal (5% w/v) and MOPS. Carefully, a 1‐mL top‐phase in the same buffer was layered on top of the bottom‐phase. Cells were either in the top‐ or the bottom‐phase. A commercially fed supplement for animals was used as chemoattractant in the phase opposite to the cells (Bioprotein, BP; Norferm, Norway). Changes in cell concentrations were monitored as optical density at 600 nm.RESULTS: (1) cells in top‐phase: −BP, 0.0001/30 min;+BP, 0.12/4 min. (2) cells in bottom‐phase: top‐phase exposed to a stream of nitrogen gas: −BP, 0.07/2 min; +BP 0.05/2 min; top‐phase not exposed to a stream of nitrogen gas: −BP, 0.08/2 min; +BP, 0.04/2 min. CONCLUSIONS: The BP proved to be an effective chemoattractant. Gravikinesis was observed with and without the presence of BP. Aerotaxis was not observed. The two‐phase assay is a sensitive, reliable, and quick procedure for the assessment of chemokinesis and gravikinesis.

1-heptene, 3-heptenes and cumene as model compounds of SBS block copolymers. Study of their photoreactions in the presence of photoinitiators of polymerization

The photoreactions of 1-heptene, 3-heptene and cumene in the presence of unimolecular and bimolecular reaction photoinitiators (1,1-dimethoxy-1-phenyl-acetophenone, DMPA, and benzophenone, BP) has been investigated. Quantum yields of the reactions and identification of the photoreaction products has permitted to elucidate the steps and the mechanism of the mentioned photoreactions. This helps to know the reactions which take place in more complicated systems, such is the case of the photopolymerization of acrylic monomers in SBS block copolymer matrices, of which these compounds could serve as models. For heptene derivatives, the photoreaction in the presence of BP takes place through direct abstraction of an allylic hydrogen atom, and in minor extension, of other hydrogen atoms of the heptene aliphatic chain. As the main form of termination, the heptenyl and the ketyl radicals formed coupled inside the solvent cage. Photoreaction in the presence of DMPA occurs by direct attack of the radicals formed from the initiator (PhCO ∗, Ph(MeO) 2C ∗, and CH 3 ∗ to the heptene double bond. When this double bond is terminal oligomerization occurs. For cumene, the photoreaction takes place through direct abstraction of the benzylic hydrogen atom both cases.

Metabolism of nicergoline (Sermion), An ergot derivative active in senile mental impairment, In rat brain

An in vitro mammalian assay system has been used to examine the importance of specific enzymes and/or enzyme ratios in the metabolic toxification/detoxification of benzo[a]pyrene (BP). The assay incorporates the postmitochondrial supernatant (S15 fraction) prepared from a rat liver homogenate as an enzyme source and V79 Chinese hamster cells as targets for chemically induced damage. In order to determine the importance of specific enzymes in the metabolic activation of benzo[a]pyrene in vitro, the enzyme pattern in the S15 fraction was modulated by pretreating the experimental animals with enzyme inducers and/or by adding enzyme inhibitors in vitro. The enzyme activity (ethoxyresorufin-O-deethylase (EROD), a measure of 3-methylcholanthrene-inducible mixed function oxidases; ethyl-morphine-N-demethylase (EMND), a measure of phenobarbital-inducible mixed function oxidases; and epoxide hydrase (EH)) in a given S15 fraction was determined, and the ability of the preparation to induce mutagenicity and / or cytotoxicity in the presence of BP was assessed. Correlations were made between the activity of a particular enzyme or enzyme ratio in the S15 fraction and the biological response produced by BP, i.e. cytotoxicity and mutagenicity.When the role of individual enzymes was evaluated, EH, but not EROD or EMND, correlated (p < 0.01) with the degree of BP-induced cytotoxicity and mutagenicity. As EH activity in the S15 fraction increased, the degree of cytotoxicity and mutagenicity observed as a result of metabolism decreased. When enzyme ratios were evaluated, we found two significant (P < 0.01) correlations; EMND/EH and EROD/EH. As these ratios increase, BP becomes more cytotoxic and mutagenic towards V79 cells. Since the adverse biological effects of BP are mediated via epoxides, these results suggest that the experimental approach described in this report will allow one to evaluate the relative importance of various enzymes and/or enzyme patterns in the metabolic toxification/detoxification of other potentially toxic chemicals.

生理的組織接着剤（ベリプラストＰ）の骨欠損填塞後の骨形成に関する組織学的解析

This paper describes the effects of fibrin adhesive material (Beriplast P ®: BP) on bone induction in bone defects formed by surgical operation. Using adult Sprague-Dawley strain rats, bone defects were formed in the cortical bones of femurs with a dental round bar 1 mm in diameter, and immediately filled with BP. Bone defects without BP served as controls.On days 1, 4, 7, 14, 30, 60, and 120 after operation, rats were fixed by transcardiac perfusion with an aldehyde mixture, and dissected bones were examined by light, transmission, and scanning-electron microscopy.In the control bones without BP, the defective regions werefirst filled with blood clots (day 1) and then with granulated tissues containing numerous fibroblasts and macrophages (day 4). In BP-filled defects, the presence of BP and surrounding fibrous tissues significantly inhibited the formation of blood clots and granulated tissues, so bone formation from the surrounding cortical bone margins was induced faster than in control bones. In addition, granulated tissues were rapidly replaced by normal bone marrow in the BP-filled defects. Because BP is biological adhesive, at 4 days after operation, most of the BP was already absorbed, but no dead space was left in the defected regions. At 2 weeks after operation, the defects were completely filled with newly-formed bones, in which an active bone remodelling by osteoblasts and osteoclasts occurred.These results show that BP is an effective biological tool in filling bone defects and in inducing new bone formation.

Generation of CD4+ blastoid T cells in recipients of BP/IFA-sensitized spleen cells

While sensitization of Lewis rats with BP/IFA does not induce EAE, recipients given BP/IFA-sensitized cells after culture with BP do develop EAE. To clarify the pathophysiology responsible for this discrepancy, cell dynamics were studied in the recipients. The CD4+ T cells from BP/ IFA-sensitized donors showed no proliferative response to BP and no change in cell size or surface molecule expression, even in the presence of BP in culture. On the other hand, the recipient cells proliferated vigorously, regardless of the presence or absence of BP. In this case, a large number of CD4+ blastoid T cells was generated only in the presence of BP in culture. Such cells showed marked upregulation of CD4, CD2, class I and II MHC, and IL2 receptor molecules, a finding we also observed in the case of BP-cultured cells from BP/CFA-sensitized rats with severe EAE. The proportion of CD4+ blastoid T cells generated after culture depended on the number of cells transferred and on the presence of BP in culture, and closely correlated with the severity of EAE in the recipients. These data suggest that BP/IFA-sensitization can also induce BP-reactive cells capable of becoming CD4+ blastoid T cells with marked upregulation of CD4, CD2, class I and II MHC, and IL2 receptor molecules directly related to potent encephalitogenicity, in vivo.

Effects of 3,4-benzopyrene on the course of cell cycle events in the chlorococcal alga Scenedesmus quadricauda

Synchronous cultures of the chlorococcal alga Scenedesmus quadricauda were grown under optimal growth conditions. The mean length of their cell cycle was approximately 20 h. The cultures were treated at the start, at the 4th, and 8th hour of the cell cycle with 3,4-benzo(a)pyrene (BP) in the range of 0.1-0.5 μg ml(-1) of final concentration. A period about 4 h was found within which no inhibitory effects could be detected even at the highest BP concentrations used. In presence of BP the rates of RNA and protein syntheses gradually decreased until complete inhibition of net syntheses occurred. In a similar way chlorophyll synthesis was inhibited, and this was followed by gradual degradation of the chlorophyll. The higher the concentration of BP the more rapid the decrease of the rates of syntheses and the earlier their complete inhibition. At low BP concentrations while DNA replications were initiated, the number of replications was lowered. At higher concentrations the initiations of DNA replications were delayed or completely suppressed. Syntheses of saccharides were the least inhibited processes in presence of BP. Starch synthesis was slowed down at the end of the cell cycle and fructose synthesis (free and sucrose bound) was even stimulated later in the cell cycle. The release of daughter coenobia, and protoplast fissions were most susceptible to BP treatment, being affected at concentrations which produced no measureble disturbances of macromolecular syntheses. At BP concentrations at which the inhibition of macromolecular syntheses occurred, the delay or suppression of mitoses was observed.

Quantitative studies on metabolic activation in vitro employing benzo[ a]pyrene as the test compound

An in vitro mammalian assay system has been used to examine the importance of specific enzymes and/or enzyme ratios in the metabolic toxification/detoxification of benzo[ a]pyrene (BP). The assay incorporates the postmitochondrial supernatant (S15 fraction) prepared from a rat liver homogenate as an enzyme source and V79 Chinese hamster cells as targets for chemically induced damage. In order to determine the importance of specific enzymes in the metabolic activation of benzo[ a]pyrene in vitro, the enzyme pattern in the S15 fraction was modulated by pretreating the experimental animals with enzyme inducers and/or by adding enzyme inhibitors in vitro. The enzyme activity (ethoxyresorufin- O-deethylase (EROD), a measure of 3-methylcholanthrene-inducible mixed function oxidases; ethyl-morphine- N-demethylase (EMND), a measure of phenobarbital-inducible mixed function oxidases; and epoxide hydrase (EH)) in a given S15 fraction was determined, and the ability of the preparation to induce mutagenicity and / or cytotoxicity in the presence of BP was assessed. Correlations were made between the activity of a particular enzyme or enzyme ratio in the S15 fraction and the biological response produced by BP, i.e. cytotoxicity and mutagenicity. When the role of individual enzymes was evaluated, EH, but not EROD or EMND, correlated ( p < 0.01) with the degree of BP-induced cytotoxicity and mutagenicity. As EH activity in the S15 fraction increased, the degree of cytotoxicity and mutagenicity observed as a result of metabolism decreased. When enzyme ratios were evaluated, we found two significant ( P < 0.01) correlations; EMND/EH and EROD/EH. As these ratios increase, BP becomes more cytotoxic and mutagenic towards V79 cells. Since the adverse biological effects of BP are mediated via epoxides, these results suggest that the experimental approach described in this report will allow one to evaluate the relative importance of various enzymes and/or enzyme patterns in the metabolic toxification/detoxification of other potentially toxic chemicals.

Microspectrofluorometric study of benzo(a)pyrene metabolization in benzo(a)pyrene-grown single living cells.

A microspectrofluorometric approach in conjunction with microelectrophoretic injection of glucose-6-P (G6P), was used to study the effect of cultivation in a benzo(a)pyrene (BP)-containing medium on the metabolization of BP, by EL2 ascites cells. The fluorescence increase which follows the microinjection of G6P to single living cells. was studied in EL2 cells grown for 24-hours, 48-hours, 10 days and 57 days in a BP-containing medium, as well as EL2 cells grown for 16 days in presence of BP and placed then for 24 or 48 hours in a BP-free medium. The effects on the induction of Aryl Hydrocarbon Hydroxylase were observed for cells so treated, and it seems that for the latter the requirement of intracellular O2 for the metabolization of BP, has been verified. Furthermore, another important factor has emerged: the intracellular BP concentration. The various spectra are discussed in function of these considerations.