Polar Derivatives Research Articles

Generalizations of Bernstein and Turán-Type Inequalities for the Polar Derivative of a Complex Polynomial

The goal of this paper is to extend to the polar derivatives some previous inequalities between the $$L^\gamma $$-norms of the derivative and of the polynomial itself, in case when the zeros are outside or inside some closed disk. Apart from this, our results also derive polar derivative analogues of some classical Bernstein and Turan-type inequalities that relate the sup-norms of a polynomial to that of its derivative on the unit circle.

Discovery of Highly Polar β-Homophenylalanine Derivatives as Nonsystemic Intestine-Targeted Dipeptidyl Peptidase IV Inhibitors.

Although intensively expressed within intestine, the precise roles of intestinal dipeptidyl peptidase IV (DPPIV) in numerous pathologies remain incompletely understood. Here, we first reported a nonsystemic intestine-targeted (NSIT) DPPIV inhibitor with β-homophenylalanine scaffold, compound 7, which selectively inhibited the intestinal rather than plasmatic DPPIV at an oral dosage as high as 30 mg/kg. We expect that compound 7 could serve as a qualified tissue-selective tool to determine undetected physiological or pathological roles of intestinal DPPIV.

Inhibition of aflatoxin B1 biosynthesis and down regulation of aflR and aflB genes in presence of benzimidazole derivatives without impairing the growth of Aspergillus flavus

Aflatoxins are mutagenic secondary metabolites produced by certain ubiquitous saprophytic fungi. These contaminate agricultural crops and pose a serious health threat to humans and livestock all over the world. Benzimidazole and its derivatives are biologically active heterocyclic compounds known for their fungicidal activity. In the present study, second and sixth position substituted benzimidazole derivatives are tested for their antifungal and anti-aflatoxigenic activity. Aflatoxigenic strain of Aspergillus flavus cultured in Yeast extract sucrose (YES) medium as well as in rice in the presence and absence of test compounds. 2-(2-Furyl) benzimidazole (FBD) showed complete inhibition of fungal growth at 50 μg/mL. However, the polar derivatives of FBD viz. 6-NFBD, 6-AFBD, 6-CAFBD, and 6-CFBD did not impair the fungal growth but effectively inhibited aflatoxin B1 biosynthesis. Significant down-regulation of aflR gene involved in regulation and aflB structural gene for aflatoxin B1 biosynthesis was observed in presence of 6-NFBD. These benzimidazole derivatives also showed good anti-aflatoxigenic activity in rice, though the IC50 concentrations in rice were comparatively higher than those in YES medium. This study summarizes the most notable structure-activity relationship (SAR) of 2-(2-Furyl) benzimidazoles for anti-aflatoxigenic and anti-fungal activities. These molecules can be further studied for their applications in industrial fermentation processes vulnerable to mold growth and subsequent aflatoxin B1 synthesis like koji fermentation, cheese production, etc.

Analysis of polycyclic aromatic hydrocarbons (PAHs) and their polar derivatives in soils of an industrial heritage city of Australia

Knowledge about polar derivatives of polycyclic aromatic hydrocarbons (PAHs) in soils is limited despite the extensive study of the environmental presence and persistence of non-polar parent PAHs. Polar PAHs have greater potential to be more toxic at low environmental concentrations compared to their homocyclic analogues. For both polar and non-polar PAHs, combustion of fossil fuels is often the main source especially in industrialised environments. This study investigated the concentration profiles of PAHs and its associated polar PAHs such as nitrated PAHs (NPAHs), oxygenated PAHs (oxy-PAHs) and nitrogen, sulphur and oxygen heterocyclic PAHs (N/S/O-heterocyclic PAHs) in a well-known industrial heritage city of Australia. The most abundant polar PAHs were 9-fluorenone (oxy-PAHs), 2-nitrofluorene (NPAHs) and carbazole (heterocyclic-PAHs). A positive correlation (r = 0.5, p < 0.01) between ∑13PAHs and ∑19 polar PAHs was observed, implying a possible spatial association between parent and polar PAHs. The concentrations of polar PAHs in soil samples, across various landuse patterns, were used to calculate the excess lifetime cancer risk (ELCR) from incidental ingestion of soils. The computed ELCR values ranged from 8.2*10−7 (industrial soils) to 2.3*10−6 (residential soils), indicating negligible cancer risks. This is the first known study on the occurrence and concentrations of polar and non-polar PAHs in any Australian city, and the results may serve a baseline purpose for improved risk assessment of contaminated sites.

Efficient Addition Polymerization of Norbornene with Polar Norbornene Derivatives by Neutral Nickel(II) Catalysts

A series of nickel complexes {4a: [(2,6-iPr2C6H3)N=CHC16H12O]Ni(Me)(Py), 4b: [(2,6-iPr2C6H2OCH3)N=CHC16H12O]-Ni(Me)(Py), 4c: [(2,6-iPr2C6H2Cl)N=CHC16H12O]Ni(Me)(Py), and 4d: [(2,6-iPr2C6H2CF3)N=CHC16H12O]Ni(Me)(Py)} based on β-ketiminato ligands bearing various electron-donating or electron-withdrawing substituents on the para-position of the aniline group were synthesized and unambiguously characterized. The X-ray crystallographic analysis showed that complexes 4b and 4d adopted a near-square-planar geometry, and the anilines bearing a para-OMe or −CF3 group were found to situate on the axial position of the metal center. All complexes exhibited high activities up to 1.25 × 107–1.35 × 107 gPNB·molNi−1·h−1 toward norbornene (NBE) addition polymerization (conversion > 91.2% in 2 min) under low loading of B(C6F5)3 (B/Ni = 3) at 30 °C, affording polymers with high molecular weight up to 2.54 × 106–3.18 × 106. Different levels of decrease in catalytic activities could be observed for all catalysts as the reaction temperature increased; 4d bearing a strong electron-withdrawing −CF3 group showed the highest activity at 70 °C, while others exhibited notable decrease in catalytic activity with the raise in reaction temperature. Complexes 4a–4d showed remarkable tolerance to polar groups and could efficiently promote the copolymerization of NBE with its polar derivatives, including NBE bearing small acetate and hydroxyl group, as well as bulky oligomers, yielding copolymers with high functional NBE incorporations. Novel NBE copolymers with high functional comonomer incorporations and improved solubility were obtained in high yields.

Some sharp upper bound estimates for the maximal modulus of polar derivative of a polynomial

In this paper, we establish some sharp upper bound estimates for the maximal modulus of polar derivative of a complex polynomial on a disk under the assumption that the polynomial has no zeros in another disk. The obtained results sharpen some already known estimates for the ordinary derivative of polynomials as special cases.

Optimization of a sustainable purification protocol for lutein and chlorophyll from spinach by-products by a saponification procedure using Box Behnken design and desirability function

The objective of this study was to develop a safe and ecologically sustainable protocol, to extract and separate lutein and chlorophyll from spinach discards. A saponification in an aqueous medium was carried out to release the phytyl aliphatic chain from the porphyrin ring of chlorophyll. Polar chlorophyll derivatives were formed, remaining in the aqueous medium, whereas apolar lutein remaining in the plant residues and was extracted thereafter by maceration in 95% ethanol. However, the saponification step may cause a significant degradation of lutein, resulting in low extraction yields. The saponification parameters were studied using response surface methodology to determine the conditions providing the highest recovery of lutein in an ethanolic extract, combined with the lowest loss of chlorophyll derivatives. Through this procedure, using the Derringer’s desirability function, we uncovered that the optimal conditions for saponification were 16 h of aqueous maceration with 3.9% (W/V) sodium hydroxide at 60 °C. This procedure can be easily scaled for high volume commercial extraction of these compounds.

Reactive, Aqueous-Dispersible Polyfluorene-Wrapped Carbon Nanotubes Modulated with an Acidochromic Switch via Azide–Alkyne Cycloaddition

Decorating hydrophobic carbon nanotube surfaces efficiently in aqueous solution without adversely affecting nanotube optoelectronic properties remains a challenge. In this work, we designed a water-soluble polyfluorene derivative that contains azide groups and polyethylene glycol grafts in the side chains. This polyfluorene derivative was used to coat carbon nanotube surfaces, producing a latently reactive and aqueous-dispersible polymer–nanotube complex. Reaction progress of the aqueous polymer–nanotube dispersion with various polar and nonpolar alkyne derivatives was followed using infrared spectroscopy. Decoration of the polymer–nanotube complex with various small molecules or polymers was found to modulate the surface properties of the resulting nanohybrid thin films. Additionally, we developed a vanillin-derived indolinooxazolidine switch that is functionalized with a terminal alkyne and appended it to the polymer–nanotube complex. This switch possesses two long-lived states that are interchangeable ...

Managing Local Order in Conjugated Polymer Blends via Polarity Contrast

The optoelectronic landscape of conjugated polymers is intimately related to their molecular arrangement and packing, with minute changes in local order, such as chain conformation and torsional backbone order/disorder, frequently having a substantial effect on macroscopic properties. While many of these local features can be manipulated via chemical design, the synthesis of a series of compounds is often required to elucidate correlations between chemical structure and macromolecular ordering. Here, we show that blending semiconducting polymers with insulating commodity plastics enables controlled manipulation of the semiconductor backbone planarity. The key is to create a polarity difference between the semiconductor backbone and its side chains, while matching the polarity of the side chains and the additive. We demonstrate the applicability of this approach through judicious comparison of regioregular poly(3-hexylthiophene) (P3HT) with two of its more polar derivatives, namely the diblock copolymer poly(3-hexylthiophene)-block-poly(ethylene oxide) (P3HT-b-PEO) and the graft polymer poly[3-but(ethylene oxide)thiophene] (P3BEOT), as well as their blends with poly(ethylene oxide) (PEO). Proximity between polar side chains and a similarly polar additive reduces steric hindrance between individual chain segments by essentially ‘expelling’ the side chains away from the semiconducting backbones. This process, which has been shown to be facilitated via exposure to polar environments such as humid air/water vapor, facilitates backbone realignment to-wards specific chain arrangements and, in particular, planar backbone configurations.

The effect of carotenoids on the concentration of singlet oxygen in lipid membranes

An effect of β-carotene and its polar derivative, zeaxanthin, on a concentration of singlet oxygen in lipid membranes was studied in a model system. The carotenoids were incorporated into the membranes of small unilamellar liposomes at a concentration of 0.15 mol% with respect to lipid. Singlet oxygen was generated in a liposome suspension via photosensitization of toluidine blue, and its concentration in a membrane was detected with application of a specific fluorescence probe (singlet oxygen sensor green reagent) located in the lipid bilayer. The results show the carotenoid-dependent decrease in the concentration of singlet oxygen in the membranes formed with unsaturated lipids (egg yolk phosphatidylcholine and digalactosyldiacylglycerol) but not in the case of the membranes formed with a saturated lipid (dimyristoylphosphatidylcholine). The effect of carotenoids was about twice as high as in the case of cholesterol present in liposomes at the same concentration. The results suggest that carotenoids protect membranes formed with unsaturated lipids against singlet oxygen through combined activity of different mechanisms: modification of structural properties of the lipid bilayers, physical quenching of singlet oxygen and chemical reactions leading to the pigment oxidation. The latter conclusion is based on the analysis of the absorption spectra of liposomes before and after light exposure. An importance of the different modes of protection by carotenoids against single oxygen toxicity towards biomembranes is discussed.

A deprotection procedure using SO3H silica gel to remove non-silyl protecting groups

Protecting groups are indispensable in organic synthesis and there is a great need for a variety of deprotection methods. Here, we investigated the scope of the application of a deprotection procedure using SO3H silica gel, which we have previously reported as a desilylation procedure. Under these conditions, -OMOM, -OSEM, -OTHP, and -OAc groups and dimethyl acetal were cleaved. Pivaloyloxy, benzyloxy and methoxy carbonyl groups remained intact and selective deprotection of TBS groups in the presence of other protecting groups was accomplished. We succeeded in cleaving an acetyl group on a secondary alcohol in a highly polar nortropine derivative. Our findings here provide another deprotection option and would be helpful in the synthesis of multifunctional compounds.

Some integral inequalities for the polar derivative of polynomials

As a generalization of well-known result due to Turan [24] for polynomials having all their zeros in |z| ? 1, Malik [17] proved that, if P(z) is a polynomial of degree n, having all its zeros in |z| ? 1, then for any ? &gt; 0, n{?2?0|P(ei?)|?d?}1/? ? {?2?0|1+ei?|?d?}1/? max |z|=1 |P?(z)|. We generalize the above inequality to polar derivatives, which as special cases include several known results in this area. Besides the paper contains some more results that generalize and sharpen several results known in this direction.

Heptafluorobutyl Chloroformate-Based Sample Preparation Protocol for Nonchiral and Chiral Amino Acid Analysis by Gas Chromatography-Mass Spectrometry.

Gas chromatography (GC) is a commonly used technique in amino acid analysis (AAA). However, one of the requirements of the application of GC for AAA is a need for the polar analytes to be converted into their volatile, thermally stable derivatives. In the last two decades, alkyl chloroformates (RCFs) have become attractive derivatization reagents. The reagents react immediately with most amino acid functional groups in aqueous matrices, and the process can easily be coupled with liquid-liquid extraction of the resulting less polar derivatives into immiscible organic phase. Here we describe a simple protocol for in situ derivatization of amino acids with heptafluorobutyl chloroformate (HFBCF) followed by subsequent chiral as well as nonchiral GC/MS (mass spectrometric) analysis on a respective nonpolar fused silica and an enantioselective Chirasil-Val capillary column.

BODIPY-loaded polymer nanoparticles: chemical structure of cargo defines leakage from nanocarrier in living cells.

Uncontrolled release of encapsulated drugs and contrast agents from biodegradable polymer nanoparticles (NPs) is a central problem in drug delivery and bioimaging. In particular, it concerns polymeric NPs prepared by nanoprecipitation, where this release (so-called burst release) can be very significant, leading to side effects and/or bioimaging artifacts. Here, we systematically studied the effect of the chemical structure of cargo molecules, BODIPY dye derivatives, on their capacity to be loaded into ∼50 nm PLGA NPs without leakage in biological media. Absorption and fluorescence spectroscopy suggested that all the dyes, except the most polar BODIPY derivative, formed blended structures with polymer NPs. Fluorescence correlation spectroscopy of dye-loaded NPs in the presence of serum proteins revealed that only the most hydrophobic BODIPY dyes, bearing one octadecyl chain or two octyl chains, remain inside the NPs, while all other derivatives are released into the serum medium. The time-lapse absorption and fluorescence studies confirmed this result, suggesting the release kinetics for the leaky NPs on the time scale of hours. Fluorescence microscopy of living cells incubated with BODIPY-loaded NPs showed that most of them exhibit strong dye leakage observed as a homogeneous distribution of fluorescence all over the cytoplasm. Importantly, NPs loaded with the most hydrophobic dyes exhibited high stability showing a dotted pattern in the perinuclear region, typical for endosomes and lysosomes. Our results highlight the significance of the cargo hydrophobicity for efficient encapsulation inside polymeric NPs prepared by nanoprecipitation, which enables designing stable cargo-loaded nanomaterials for bioimaging and drug delivery.

Evolving spin periodicity and lock-in transition in the frustrated ordered ilmenite-type β−Mn2InSbO6

Polar magnets are promising materials for applications such as multiferroics or in spintronics. In double-corundum-related oxides, the cation ordering imposes a polar structure and the use of high pressure facilitates the insertion of magnetic cations into the compounds. Here we present the high-pressure synthesis of a polar and ferrimagnetic corundum derivative of ${\mathrm{Mn}}_{2}{\mathrm{InSbO}}_{6}$, which adopts the ordered-ilmenite-type structure. Neutron powder diffraction reveals that the high-temperature nearly collinear ferrimagnetic phase evolves to an incommensurate helical structure with ${k}_{\ensuremath{\delta}}=[0\phantom{\rule{0.28em}{0ex}}0\phantom{\rule{0.28em}{0ex}}{k}_{z}]$ propagation vector, which then locks to the commensurate value of ${k}_{z}=1/8$. This complex magnetic behavior is likely to be related to magnetic frustration and the polar nature of the ordered double-corundum structure.

Some inequalities concerning integral estimates for polynomials

For the class of polynomials of degree n having all their zeros in where k ≤ 1, Aziz and Shah [4] proved that for each r > 0,In this paper, we extend this inequality to the polar derivative in the sense that we take the polar derivative DαP(z) in place of ordinary derivative P′(z) of polynomial P(z).

New Integral Mean Estimates for the Polar Derivative of a Polynomial

Let p(z) be a polynomial of degree n and for α ∈ C, let Dαp(z):= np(z) + (α − z)p′(z) denote the polar derivative of the polynomial p(z) with respect to α. In this paper, we obtain certain integral inequalities concerning the polar derivative of a polynomial, which besides yielding some interesting results, also includes some well-known theorems as special cases. Moreover we refine some Zygmund type inequalities for the polar derivative of a polynomial and present compact generalizations of some prior results.

Preparation of polar group derivative β-cyclodextrin bonded hydride silica chiral stationary phases and their chromatography separation performances

Three novel β-cyclodextrin compounds derived with piperidine which is flexible, l-proline containing a chiral center, ionic liquid with 3,5-diamino-1,2,4-triazole as the cation were designed and synthesized as chiral selectors for enantiomer separation, whose name were (mono-6-deoxy-6-(piperidine)-β-cyclodextrin, mono-6-deoxy-6-(l-proline)-β-cyclodextrin, mono-6-deoxy-6-(3,5-diamino-1,2,4-triazole)-β-cyclodextrin, multi-substituted 3,5-diamino-1,2,4-triazole-(p-toluenesulfonic)-β-cyclodextrin), respectively. In addition, to enhance the polarity of chiral stationary phases, hydrosilylation and silylation reactions were implemented to derive ordinary silica, the common used selector carrier, to hydride silica, whose surface is covered with proton. 31 pyrrolidine compounds and some chiral drugs were tested in both polar organic mobile phase mode and normal mobile phase mode. 6-Deoxy-6-l-proline-β-cyclodextrin-CSP showed satisfactory separations in polar organic mobile phase mode and exihibited a strong separation capability in different pH values; multi-substituted 3,5-diamino-1,2,4-triazole-(p-toluenesulfonic)-β-cyclodextrin-CSP can separate pyrrolidine compounds in both mobile phase modes with high resolutions and separation efficiency compared to commercially available CSPs, making it to be the most valuable object to study. The composition of mobile phase, type of stationary phase as well as the peak problem of chromatograms was discussed deeply.

Geometry of projected connections, Zak phase, and electric polarization

The concept of the Zak phase lies at the core of the modern theory of electric polarization. It is defined using the components of the Bloch wave functions in a certain basis, which is not captured by the standard expression for Berry potential. We provide a consistent geometric interpretation of the Zak phase in terms of projected connections. In the context of Bloch states, we relate the transformation law of projected Berry potential with classical currents that contribute to the time derivative of the electric polarization. This gives a new argument for the Zak phase formula for the electronic contribution to the polarization. We demonstrate that the Wannier functions play a key role in the description of an adiabatic current in a periodic system.

Gradients of Synchrotron Polarization: Tracing 3D Distribution of Magnetic Fields

Abstract We describe a new technique for probing galactic and extragalactic 2D and 3D magnetic field distribution using gradients of polarized synchrotron emission. The fluctuations of magnetic field are elongated along the ambient magnetic field. Therefore, the field variations are maximal perpendicular to the B-field. This allows tracing the B-field with synchrotron polarization gradients. We demonstrate that the Faraday depolarization allows us to map 3D B-field structure. The depolarization ensures that the polarization gradients sample the regions close to the observer with the sampling depth controlled by the frequency of radiation. We also analyze the B-field properties along the line of sight (LOS) by applying the gradient technique to the wavelength derivative of synchrotron polarization. This Synchrotron Derivative Polarization Gradients technique can recover the 3D vectors of the underlying B-fields. The new techniques are different from the Faraday tomography, as they provide a way to map the 3D distribution of B-field components perpendicular to the LOS. In addition, we find that the alignment of gradients of polarization with the synchrotron polarization can be used to separate the contribution of the foreground from the polarization of cosmological origin. We notice that the same alignment is also present for the dust polarization.