Fresh frozen plasma and platelet concentrates may increase plasma anti-diphtheria toxin IgG concentrations: implications for diphtheria fusion protein therapy

We are developing two fusion proteins consisting of a diphtheria toxin (DT) linked to either granulocyte macrophage colony stimulating factor (DT₃₈₈-GMCSF) or interleukin-3 (DT₃₈₈-IL3). In trials, patients with anti-DT IgG concentrations >2.5 μg/ml had significantly lower concentrations of either fusion protein. DT₃₈₉-IL2 is currently FDA approved for the treatment of cutaneous T-cell lymphomas. We noted increased concentrations of anti-DT IgG after administration of platelet concentrates (PC). Because many of these patients require transfusions, we measured the anti-DT IgG content of FFP and PC. We assayed 14 bags of FFP and 12 bags of single-donor PCs for anti-DT IgG by an enzymoimmunoassay against DT₃₈₉-IL2, DT₃₈₈-IL3, DT₃₈₈-GMCSF. The median (percent of samples positive) of anti-DT IgG concentrations in PC against DT₃₈₈-GMCSF, DT₃₈₈-IL3, DT₃₈₉-IL2 was 0.8 μg/ml (83%), 0.7 μg/ml (83%), and 0.3 μg/ml (58%), respectively. The median (percent of samples positive) anti-DT IgG concentration in FFP against DT₃₈₈-GMCSF, DT₃₈₈-IL3, and DT₃₈₉-IL2 was 2.1 μg/ml (86%), 1.9 μg/ml (93%), and 1.4 μg/ml (86%), respectively. There was a strong association between anti-DT₃₈₉IL2 IgG, anti-DT₃₈₈IL3 IgG, and anti-DT₃₈₈GMCSF IgG concentrations in both the FFP (95.6%) and PC (76.3%). Assuming a plasma volume of 3 l in a 70 kg patient, a single FFP unit would increase the plasma anti-DT₃₈₉IL2 IgG, anti-DT₃₈₈IL3 IgG, and anti-DT₃₈₈GMCSF IgG by 0.13 μg/ml, 0.17 μg/ml, and 0.19 μg/ml, respectively. For PC, a single unit would increase plasma anti-DT₃₈₉-IL2 IgG, anti-DT₃₈₈-IL3 IgG, and anti-DT₃₈₈-GMCSF IgG by 0.03 μg/ml, 0.06 μg/ml, and 0.07 μg/ml, respectively. In conclusion, a single FFP or PC appears to minimally increase anti-DT IgG concentrations, but multiple units may significantly do such.     

MOF‐Based Transparent Passivation Layer Modified ZnO Nanorod Arrays for Enhanced Photo‐Electrochemical Water Splitting

This study introduces zeolitic imidazolate framework‐8 (ZIF‐8) as the first metal‐organic framework based transparent surface passivation layer for photo‐electrochemical (PEC) water splitting. A significant enhancement for PEC water oxidation is demonstrated based on the in situ seamless coating of ZIF‐8 surface passivation layer on Ni foam (NF) supported ZnO nanorod arrays photoanode. The PEC performance is improved by optimizing the ZIF‐8 thickness and by grafting Ni(OH)₂ nanosheets as synergetic co‐catalyst. With respect to ZnO/NF, the optimized Ni(OH)₂/ZIF‐8/ZnO/NF photoanode exhibits a two times larger photocurrent density of 1.95 mA cm^?2 and also a two times larger incident photon to current conversion efficiency of 40.05% (350 nm) at 1.23 V versus RHE (V_RHE) under AM 1.5 G. The synergetic surface passivation and the co‐catalyst modification contribute to prolonging the charge lifetime, to promoting the charge transfer, and to decreasing the overpotential for water oxidation.     

Ab initio study of weakly bound halogen complexes: RX⋯PH3

Ab initio calculations were employed to study the role of ipso carbon hybridization in halogenated compounds RX (R = methyl, phenyl, acetyl, H and X = F, Cl, Br and I) and its interaction with a phosphorus atom, as occurs in the halogen bonded complex type RX?PH₃. The analysis was performed using ab initio MP2, MP4 and CCSD(T) methods. Systematic energy analysis found that the interaction energies are in the range ?4.14 to ?11.92 kJ mol^?1 (at MP2 level without ZPE correction). Effects of electronic correlation levels were evaluated at MP4 and CCSD(T) levels and a reduction of up to 27 % in interaction energy obtained in MP2 was observed. Analysis of the electrostatic maps confirms that the PhCl?PH₃ and all MeX?PH₃ complexes are unstable. NBO analysis suggested that the charge transfer between the moieties is bigger when using iodine than bromine and chlorine. The electrical properties of these complexes (dipole and polarizability) were determined and the most important observed aspect was the systematic increase at the dipole polarizability, given by the interaction polarizability. This increase is in the range of 0.7–6.7 u.a. (about 3–7 %).     

Complex formation with alkali and alkaline earth metal ions of cyclic octapeptides,cyclo(Phe-Pro)4, cyclo(Leu-Pro)4, and cyclo[Lys(Z)-Pro]4

Complex formation with alkali and alkaline earth metal ions of cyclic octapeptides, cyclo(Phe-Pro)₄, cyclo(Leu-Pro)₄, and cyclo[Lys(Z)-Pro]₄ was investigated in relation to conformation. In an alcohol solution, cyclo(Phe-Pro)₄ did not form complexes. However, cyclo(Leu-Pro)₄ and cyclo[Lys(Z)-Pro]₄ formed complexes selectively with Ba²⁺ and Ca²⁺ ions. Changing the solvent from alcohol to acetonitrile, the complexation behavior was very different. In acetonitrile, cyclo(Phe-Pro)₄ was found to form a complex with Ba²⁺, and CD spectra of cyclo(Leu-Pro)₄ and cyclo[Lys(Z)-Pro]₄ changed sharply on complexation with K⁺. Rate constants of the complex formation between the cyclic octapeptides and metal salts were in the range of 0.7–12 L mol^?1 min^?1 in an alcohol solution. One of the two types of complex formation in acetonitrile was much faster than that in an alcohol solution.     

Temperature and Electrical Poling Effects on Ionic Motion in MAPbI3 Photovoltaic Cells

Despite their excellent power conversion efficiency, MAPbI₃ solar cells exhibit strong hysteresis that hinders reliable device operation. Herein it is shown that ionic motion is the dominant mechanism underlying hysteresis of MAPbI₃ solar cells by studying the effects of electrical poling in different temperature ranges. Complete suppression of the hysteresis below 170 K is consistent with temperature activated diffusion of I^? anions and/or the motion of the MA⁺ cations. Ionic motion has important effect on the overall efficiency of the MAPbI₃ solar cells: the initial decrease of the power conversion efficiency while lowering the operating temperature is recovered and even enhanced up to 20% of its original value by applying an electrical poling. The open circuit voltage significantly increases and the current density fully recovers due to the reduction of the electron extraction barrier at the TiO₂/MAPbI₃ interface driven by the charge accumulation at the interface. Moreover, beside TiO₂/MAPbI₃ interfacial charge transfer, charge transport in TiO₂ strongly affects the photovoltaic performance, as revealed by MAPbI₃/ms‐TiO₂ field effect transistors. These results establish the basis to develop effective strategies to mitigate operational instability of perovskites solar cells.     

Surface Charge Densities and Membrane Fluidities in Thylakoids with Different Degrees of Thylakoid Appression After Norflurazon Treatment

Wheat seedlings (Triticum aestivum L.) develop plastids (etioplasts and chloroplasts) which exhibit alterations in inner membrane organisation after treatment with Norflurazon (NF), an inhibitor of carotenoid biosynthesis. In dark-grown plants, it results in a decreased amount of partitions (contact zones) between prothylakoids. Under weak red radiation (WRR), plants contain chloroplasts devoid of grana. Using the fluorescent probe 9-amino acridine (9-AA), the average surface charge density of isolated prothylakoids (PTs) was –21.8±3.2 mC m^–2 and –27.4±2.6 mC m^–2 in the control and after treatment, respectively. Thylakoid membranes isolated from plants grown under WRR exhibited slightly more negative values, –23.5±2.9 mC m^–2 and –29.0±2.1 mC m^–2, in control and after NF treatment, respectively. The surface charge density of de-stacked thylakoids from greenhouse-grown untreated plants, containing extensive grana stacking, was –34.3±2.5 mC m^–2. Assays using the fluorescent probe of DPH (1,6-diphenyl-1,3,5-hexatriene) showed a higher polarisation value when incorporated into thylakoids from NF-treated plants compared to untreated plants grown under WRR. The highest polarisation value was found in untreated plants grown in the greenhouse. This indicates a lower rotation transition of the probe in the lipid environment of thylakoids after NF treatment, which can be interpreted as more rigid membranes. Hence the surface charge density and the mobility of membrane components may play a major role for the formation of partitions in dark-grown plants and in the formation of grana in plants grown under WRR.     

Function of two β-carotenes near the D1 and D2 proteins in photosystem II dimers

The antenna proteins in photosystem II (PSII) not only promote energy transfer to the photosynthetic reaction center (RC) but provide also an efficient cation sink to re-reduce chlorophyll a if the electron transfer (ET) from the Mn-cluster is inhibited. Using the newest PSII dimer crystal structure (3.0 Å resolution), in which 11 β-carotene molecules (Car) and 14 lipids are visible in the PSII monomer, we calculated the redox potentials (E_m) of one-electron oxidation for all Car (E_m(Car)) by solving the Poisson-Boltzmann equation. In each PSII monomer, the D1 protein harbors a previously unlocated Car (Car_D1) in van der Waals contact with the chlorin ring of Chl_Z(D1). Each Car_D1 in the PSII dimer complex is located in the interface between the D1 and CP47 subunits, together with another four Car of the other PSII monomer and several lipid molecules. The proximity of Car bridging between Car_D1 and plastoquinone/Q_A may imply a direct charge recombination of Car⁺Q_A⁻. The calculated E_m(Car_D1) and E_m(Chl_Z(D1)) are, respectively, 83 and 126 mV higher than E_m(Car_D2) and E_m(Chl_Z(D2)), which could explain why Car_D2⁺ and Chl_Z(D2)⁺ are observed rather than the corresponding Car_D1⁺ and Chl_Z(D1)⁺.     

Variation of Charge Transfer in Zn-naphtholimines with TCNQ

The charge transfer in charge transfer complexes, based on Zinc-naphtholimines (Zn[RNAFIN]₂) with TCNQ is studied in the present paper. New electronic states form with the effect of corresponding transition bands in vibrational spectra. This proves the existence of mixed valence complexes. Band peak shifts in the visible spectral region are manifest, which provide for the evaluation of the charge transfer (CT). In this work the CT is calculated by use of the CN stretch band shift.Due to this results, we prove that an increase of the ligand volume of the donor (RNAFIN) abates the degree of charge transfer.     

Semiempirical MNDO/ZINDO study of linker effects on charge transfer in nitrobenzyl-substituted tetramethyl-fulvalenes

Semiempirical MNDO and ZINDO calculations have been performed to investigate the ground states of the neutral molecules and mono- and di-cations of nitrobenzyl-substituted tetramethylfulvalene (TMF), tetramethyl-tetrahydrofulvalene (TMTHF), and tetramethyl-tetrathiafulvalene (TMTTF). In particular, the effects of the linker groups on the direct charge transfer between the fulvalene and the nitrobenzyl groups have been studied. As linkers,-(CH₂)₂-, -CH₂O-,-CH₂S-, and -CO- were used. The coefficients of the highest occupied and lowest unoccupied molecular orbitals, the oscillator strengths and excited-state dipole moments for the vertical excitations from the neutral ground states, as obtained with SCI calculations, are reported. Although the dipole moments increase by 40–50 D when exciting from the HOMO localized on the fulvalene fragment to the LUMO localized on the nitrobenzyl part, all four linkers are found to be good insulators and thus, no direct optical donor to acceptor charge transfer can be observed. An alternative route, the photoinduced charge transfer process involving local excitations to form metastable intermediate states, is discussed. Due to the insulating properties of the linkers, these will then efficiently stabilize the charge transfer complex.     

Nitrogen-containing polyhydroxylated aromatics as HIV-1 integrase inhibitors: synthesis,structure-activity relationship analysis,and biological activity

Four series of forty-five nitrogen-containing polyhydroxylated aromatics based on caffeic acid phenethyl ester were designed and synthesized as HIV-1 integrase (IN) inhibitors. Most of these compounds inhibited IN catalytic activities in low micromolar range. Among these new analogues, compounds 9e and 9f were the most potent IN inhibitors with IC₅₀ value of 0.7 μM against strand transfer reaction. Their key structure-activity relationships were also discussed.     

Degradation of Triazine-2-14C Metsulfuron–Methyl in Soil from an Oil Palm Plantation

Triazine-2-¹⁴C metsulfuron–methyl is a selective, systemic sulfonylurea herbicide. Degradation studies in soils are essential for the evaluation of the persistence of pesticides and their breakdown products. The purpose of the present study was to investigate the degradation of triazine-2-¹⁴C metsulfuron–methyl in soil under laboratory conditions. A High Performance Liquid Chromatograph (HPLC) equipped with an UV detector and an on-line radio-chemical detector, plus a Supelco Discovery column (250 x 4.6 mm, 5 μm), and PRP–1 column (305 x 7.0 mm, 10 μm) was used for the HPLC analysis. The radioactivity was determined by a Liquid Scintillation Counter (LSC) in scintillation fluid. The soil used was both sterilized and non-sterilized in order to observe the involvement of soil microbes. The estimated DT₅₀ and DT₉₀ values of metsulfuron-methyl in a non-sterile system were observed to be 13 and 44 days, whereas in sterilized soil, the DT₅₀ and DT₉₀ were 31 and 70 days, respectively. The principal degradation product after 60 days was CO₂. The higher cumulative amount of ¹⁴CO₂ in ¹⁴C- triazine in the non-sterilized soil compared to that in the sterile system suggests that biological degradation by soil micro-organisms significantly contributes to the dissipation of the compound. The major routes of degradation were O-demethylation, sulfonylurea bridge cleavage and the triazine “ring-opened.”     

Conformational change of poly( -lysine) induced by lipid vesicles of dilauroylphosphatidic acid

The effect of negatively charged dilauroylphosphatidic acid (DLPA) vesicles on the conformation of poly( -lysine) was investigated by circular dichroism measurements. DLPA vesicles induced a confomiational change Of poly( -lysine) from the random coil to β-structure in 5 mM Tes, pH 7.0. The fraction of induced β-structure (F_β) was determined via a procedure of curve fit the observed spectra to the reference spectra. F_β increased linearly with the molar ratio, r, of DLPA to lysine residues up to r 0.7, and reached a saturation value of 1 at r > 1. Within the range 0.7 r 1, precipitation occurred. The effect of dilution of the negative charge on vesicle membranes was examined by mixing DLPA with dilauroylphosphatidylcholine (DLPC). Although the β-structure Of poly -lysine) was also induced by mixed vesicles, the saturation value of F_β decreased with decreasing DLPA content in mixed vesicles. The variation in saturation value of F_β with the composition of mixed vesicles was interpreted in terms of the change in average distance between DLPA head groups in mixed vesicles.     

A two-component sex attractant for males of the geometrid moth Alsophila quadripunctata

The binary mixture of the hydrocarbons (3Z,6Z,9Z)-3,6,9-nonadecatriene and (6Z,9Z)-6,9-nonadecadiene is a sex attractant for males of Alsophila quadripunctata Esp. (Lepidoptera, Geometridae). Triene/diene ratios from 1:1 to 1:0.01 attracted males in the field, the ratios 1:1 and 1:0.7 were most effective. The triene on its own also attracted males, but in significantly lower numbers than the 1:1 mixture. In a dosage test the highest dose, 1800 g of 1:0.8 [triene:diene] mixture applied to rubber caps was most effective. This is the first report of a geometrid sex attractant with field activity containing more than one component.

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Zusammenfassung Die binäre Mischung der Kohlenwasserstoffe (3Z,6Z,9Z)-3,6,9-Nonadecatrien [ZZZ3,6,9-19:H] und (6Z,9Z)-6,9-Nonadecadien [ZZ6,9-19:H] in den Verhältnissen 1:1 bis 1:0.01 erwies sich im Freiland als Sexuallockstoff für Männchen von Alsophila quadripunctata (Geometridae, Lepidoptera). Dabei besaß die 1:1-Mischung die beste Fängigkeit, das Nonadecatrien allein lockte schlechter, während das C₁₉-Alkadien unwirksam war. Ein Dosiswirksamkeitstest ergab bei Köderbeladungen von 1.8 mg (Trien:Dien + 1:0.8) die besten Fangergebnisse. Im Verlauf der Untersuchungen wurden weitere zwölf geometrische-oder positionsisomere C₁₉-Polyenkohlenwasserstoffe getestet, wobei keine der geprüften Verbindungen Attraktant-oder Inhibitorwirkung zeigte.

     

NAD-phenol complex formation, the inhibition of malate dehydrogenase by phenols, and the influence of phenol substitutents on inhibitory effectiveness.

Kinetic analyses indicate that inhibition by phenols of the forward reaction of malate dehydrogenase involves the binding of two molecules of phenol. One is bound as phenol, the other as a charge transfer complex of phenol with NAD. Inhibition of the reverse reaction by phenol involves the binding of only a single phenol molecule per active unit of enzyme. Kinetic evidence for this binding pattern is supported by spectral evidence in which ultraviolet absorbance and circular dichroism studies show binding of the NAD-phenol complex by malate dehydrogenase. Circular dichroism difference spectra indicate that phenol alone also binds to malate dehydrogenase.The apparent inhibition constants for fourteen variously substituted phenols were found to be significantly correlated with the hydrophobic binding constant (π), the Hammet σ function and the NAD-phenol charge transfer association constant of the individual phenols. The degree of dependency of the apparent K_i on the hydrophobicity of phenols suggests that the observed inhibition occurs via binding of phenol and/or NAD-phenol complex in hydrophobic regions of the malate dehydrogenase molecule.     

Application of π acceptors to the spectrophotometric and spectrofluorimetric determination of vincamine and naftidrofuryl oxalate in their pharmaceutical preparations

Three different spectrophotometric and two spectrofluorimetric methods have been developed and validated for the determination of vincamine (VN) and naftidrofuryl oxalate (NF) in tablets. The spectrophotometric methods depend on charge transfer complex formation between each of VN and NF with 7,7,8,8‐tetracyano‐quinodimethane (TCNQ), 2,6‐dichloroquinone‐4‐chloroimide (DCQ) and 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) at 843, 580 and 588 nm, respectively. The spectrofluorimetric methods are based on the formation of charge transfer complex between each of the two drugs and TCNQ, with measurement of the fluorophore formed at 312/375 and 284/612 nm, respectively, or with DDQ at 400/475 and 284/396 nm, respectively. In the spectrophotometric measurements, Beer's law was obeyed at concentration ranges of 1.5–16, 10–180 and 12–140 μg/ml for VN with TCNQ, DCQ, and DDQ, respectively. For NF, the corresponding concentrations were 2–28, 5–75 and 25–150 μg/ml with TCNQ, DCQ, and DDQ, respectively. In the spectrofluorimetric measurements, the ranges for VN were 0.05–0.9 and 0.3–4 μg/ml with TCNQ and DDQ, respectively, whereas for NF the ranges were 0.05–0.85 and 0.5–8 μg/ml with TCNQ and DDQ, respectively. The different experimental parameters affecting the development and stability of the formed color or fluorophore were studied and optimized and the molar ratios of the complexes were calculated. The proposed methods were validated according to ICH guidelines and were successfully applied for the determination of VN and NF in their tablet dosage forms.     

Electric-field dependence of the quantum yield in reaction centers of photosynthetic bacteria

Multilayer Langmuir-Blodgett films of reaction centers from the photosynthetic bacterium Rhodopseudomonas sphaeroides have been fabricated with partial net orientation. The films showed substantial electrical response under pulsed illumination. From measurements of the light-induced voltage generated across the Langmuir-Blodgett film, we have succeeded in quantitating the electric-field dependence of the quantum yield of charge separation in photosynthesis. The results presented here are compared with our previous determination of the field effect on quantum yield, in which flash-activated charge separation as a function of the applied field was assayed by the extent of bacteriochlorophyll dimer, (BChl)₂, oxidation measured optically at 860 nm. The two methods provided consistent dependencies of quantum yield on applied electric field. Analysis of the data reveals that the quantum yield of (BChl)^⨥₂BPhQ^⨪_A formation decreases from a value of 0.96 at zero applied field to about 0.75 for a field of 120 mV/nm vectorially directed to hinder light-activated electron transfer. For oppositely applied fields, the quantum yield saturates at unity. The source of the effects is considered to reside in the electric field dependence of the free-energy difference between the energy levels that are involved in the initial charge separation between the (BChl)₂ in the first singlet excited state, (BChl)1₂, through the bacteriopheophytin, BPh, to the primary ubiquinone, Q_A. Possible contributions to the field-induced loss of quantum yield of (BChl)^⨥₂BPhQ^⨪_A formation are: (1) a decrease in the free-energy gap between the states (BChl)1₂ and (BChl)^⨥₂BPh^⨪Q_A, leading to an increased rate of decay via the excited singlet state back to the ground state; (2) a stimulated return from (BChl)^⨥₂BPh^⨪Q_A directly or via the (BChl)₂ triplet state to the ground state and (3) an impeded electron transfer from (BChl)^⨥₂BPh^⨪Q_A to (BChl)^⨥₂BPhQ^⨪_A. These possibilities are discussed. Correlation of the electrical response with measurements of the photo-induced absorbance change allows determination of the projection of the electron-transfer distance on the normal to the plane of the film, which is in good agreement with previous measurements using different techniques.     

The ASPP interaction network: electrostatic differentiation between pro‐ and anti‐apoptotic proteins

The ASPP proteins are apoptosis regulators: ASPP1 and ASPP2 promote, while iASPP inhibits, apoptosis. The mechanism by which these different outcomes are achieved is still unknown. The C‐terminal ankyrin repeats and SH3 domain (ANK‐SH3) mediate the interactions of the ASPP proteins with major apoptosis regulators such as p53, Bcl‐2, and NFκB. The structure of the complex between ASPP2_ANK‐SH3 and the core domain of p53 (p53CD) was previously determined. We have recently characterized the individual interactions of ASPP2_ANK‐SH3 with Bcl‐2 and NFκB, as well as a regulatory intramolecular interaction with the proline rich domain of ASPP2. Here we compared the ASPP interactions at two levels: ASPP2_ANK‐SH3 with different proteins, and different ASPP family members with each protein partner. We found that the binding sites of ASPP2 to p53CD, Bcl‐2, and NFκB are different, yet lie on the same face of ASPP2_ANK‐SH3. The intramolecular binding site to the proline rich domain overlaps the three intermolecular binding sites. To reveal the basis of functional diversity in the ASPP family, we compared their protein‐binding domains. A subset of surface‐exposed residues differentiates ASPP1 and ASPP2 from iASPP: ASPP1/2 are more negatively charged in specific residues that contact positively charged residues of p53CD, Bcl‐2, and NFκB. We also found a gain of positive charge at the non‐protein binding face of ASPP1/2, suggesting a role in electrostatic direction towards the negatively charged protein binding face. The electrostatic differences in binding interfaces between the ASPP proteins may be one of the causes for their different function. Copyright © 2010 John Wiley & Sons, Ltd.     

Spatial Charge Storage within Honeycomb‐Carbon Frameworks for Ultrafast Supercapacitors with High Energy and Power Densities

Carbon‐based supercapacitors store charge through the adsorption of electrolyte ions onto the carbon surface. Therefore, it would be more attractive for the enhanced charge storage if the locations for storing charge can be extended from carbon surface to space. Here, a novel spatial charge storage mechanism based on counterion effect from Fe(CN)₆^3? ions bridged by oxygen groups and confined into honeycomb‐carbon frameworks is presented, which can provide additionally spatial charge storage for electrical double‐layer capacitances in a negative potential region and pseudocapacitances from Fe(CN)₆^3?/Fe(CN)₆^4? in a positive potential region. More importantly, an ultrafast supercapacitor based on this novelty carbon can be charged/discharged within 0.7 s to deliver both high specific energy of 15 W h kg^?1 and ultrahigh specific power of 79.1 kW kg^?1 in 1 m Na₂SO₄ electrolyte, much higher than those of previously reported asymmetric supercapacitors in aqueous electrolytes, as well as excellent cycling stability. These features suggest a new generation of ultrafast asymmetric supercapacitors as novel high‐performance energy storage devices.