Hydrophilic Acceptor Research Articles

Morphological and Device Evaluation of an Amphiphilic Block Copolymer for Organic Photovoltaic Applications

We report the morphological and photovoltaic evaluation of a novel fully conjugated donor/acceptor block copolymer system based on the P3HT-b-PFTBT scaffold. The incorporation of hydrophilic tetraethylene glycol side-chains into the PFTBT acceptor block generates an amphiphilic species whose properties provide demonstrable benefits over traditional systems. This design strategy facilitates isolation of the block copolymer from homopolymer impurities present in the reaction mixture, and we show that this purification leads to better-defined morphologies. The chemical disparity introduced between donor and acceptor blocks causes spontaneous microphase separation into well-defined domains, which we demonstrate with a combination of spectroscopy, microscopy, and X-ray scattering. The morphological advantages of this system are significant; however, preliminary device characterization indicates a loss of electron mobility in the hydrophilic acceptor block.

The phylogenetic theory of general pathology. The development of seven biological functions, seven specific ones and etiological factors of metabolic epidemics, millions years' common pathogenesis and basics of prevention.

The clearer realization is coming that in general biology, medicine, historical science, in biologic phylogenetic anamnesis of Homo sapiens a task exists only one by its significance and unresolved still: to establish historical succession of becoming of specific etiologic factors of every metabolic epidemic and to understand becoming of millions years' common pathogenesis of all metabolic pandemics. The carnivorous feeding by ocean, herbivorous feeding of ancestors of rodents and Homo sapiens by dry land; misusing carnivorous food by phylogenetically herbivorous human during last centuries, disorder of biological function of trophology, biological reaction of exotrophy, pathology of biologic functions of adaptation and endoecology, features of cognitive biological function formed etiological factors of atherosclerosis and atheromatosis. The abnormalities of biological reaction metabolism↔micro-circulation; discrepancy of mechanisms of regulation of biological reaction at 2d and 3d levels of relative biological perfection in vivo, disorder of biological function of adaptation, biological reaction of compensation formed etiological factors of metabolic arterial hypertension. The synthesis of fatty acids in phylogenesis millions of years before of glucose, preference of cells to absorb fatty acids instead of glucose; previously in phylogenesis effect of hyperglycemia, glucagon and late function of insulin formed priority of metabolism of fatty acids in energetics of organisms and glucose only in the second instance. The formation in phylogenesis of methodological mode of biological subordination in functioning of humoral mediators, incapability of insulin late in phylogenesis of blocking adaptive action of humoral mediators earlier in phylogenesis, especially in visceral fatty tissue form etiological factors of resistance to insulin. The functional limitation of cognitive biological function, difficulties in maintaining unity of internal medium of organism and effects of aphysiologic factors of external medium produces necessity of completing cognitive biological function with activation of biological reaction of apoptosis and autophagy. This occurrence forms etiologic factors of metabolic syndrome - a local pathology of early, visceral, limited in numbers of cells of pool of insulin-independent visceral fatty tissue. The inconsistency of cognitive biological function, necessity of correcting it by more effective biological function of intellect, role of insulin in energy support of new biological function - locomotion, formation of unlimited in numbers of cells а pool late in phylogenesis of insulin-dependent subcutaneous adipocytes, formed etiological factors of obesity. The biological function of depositing of fatty acids in phylogenesis in vivo is characterized by etiological dependence: depositing of fatty acids occurs in the form of non-polar triglycerides and releasing into intercellular medium occurs only in form of polar unesterified fatty acids. The features of induction with substrate, formation of positioning isoforms of fatty acids, impossibility of hydrolyzing them at effecting of hormone-dependent lipase compel to eliminate aphysiologic triglycerides from liver together with hepatocytes implementing biological reactions of apoptosis and autophagy. They become etiological factors of non-alcoholic fatty disease of liver; these are aphysiologic positioning iusoforms of triglycerides as palmitoyl-palmitol-palmitate and stearyl-stearyl-stearate. The formation of endogenous hyperuricemia in phylogenesis was initiated by 2 mutations. The first one - a gene of ascorbic acid "minus" deprived Homo sapiens of synthesis of hydrophilic acceptor of active forms of oxygen. The second one - a gene of uricase "minus" blocked synthesis of allantoin but provided a possibility of re-absorbing uric acid from a pool of primary urine and use it in vivo as an acceptor of active forms of oxygen instead of ascorbic acid under realization of biological function of endoecology,biologic reaction of inflammation.

Interfacial Organization in Dipolar Dye-Based Organic Nanoparticles Probed by Second-Harmonic Scattering

We have undertaken polarization-resolved SHS experiments to investigate a series of two fluorescent organic nanoparticles (FONs) made from dipolar dyes bearing a triphenylamine-donating end-group and a slightly hydrophilic acceptor end-group. The FONs, which show very large negative surface potentials, responsible for their good colloidal stability in water, are very bright SHS emitters in water, attractive for single-particle tracking and bioimaging. With the polarization-resolved SHS technique, we come up with a new and noninvasive method to gain insight into the origin of the surface potential of the FONs, as well as into their evolution upon change of ionic strength by following their multipolar response when adding salt. In pure water, the polarization-resolved SHS spectroscopy reveals the presence of a region of local polar order close to the surface (i.e., orientation of the dipolar dyes), leading to a strong dipolar contribution. Quite interestingly, when adding KCl salt, the initial two-lobe SHS ...

The release profiles of intact and enzymatically digested hyaluronic acid from semisolid formulations using multi-layer membrane system

A multi-layer membrane system was used to measure in vitro release of hydrophilic macromolecules such as hyaluronic acid (HA) from semisolid formulations. One enzymatically digested HA-derivative with molecular mass of 22 kDa (HA-D) and 1200 kDa intact HA (HA) were incorporated into three semisolid formulations: water-containing hydrophilic ointment (WHO), amphiphilic cream (AC) and water-containing wool wax alcohol ointment (WWO). Because of the high hydrophilic properties of HA-D and HA, the artificial model membranes consisted of collodion as the matrix and glycerol as the hydrophilic acceptor phase. The area under the concentration–time curve and the mean dissolution time were used as a quantitative parameter to characterise the rate and extent of release in vitro. This study showed that the HA-D and HA release as hydrophilic substances from WHO was higher than both from AC and WWO. It was observed that 83% of HA-D1 was released from WHO after 2 h; in contrast, only 10% was released from 2% HA from the same vehicle during the same time. In conclusion, the in vitro availability of enzymatically digested HA-D was higher for WHO than for the other formulations, AC and WWO. Similarly, the availability of HA-D was higher than that of HA from the same formulations.

Directional photochemical processes with an amphiphilic anthraceno–ruthenium complex in dihexadecyl phosphate vesicles

Excitation of an amphiphilic anthraceno–ruthenium complex, which serves as an antenna-sensitizer complex, leads to two kinds of anthracene triplet states, one of which is bleached by a hydrophilic acceptor and the other by a hydrophobic acceptor in dihexadecyl phosphate vesicles; the latter process is directional from the surface to the interior of the bilayer membrane.

Release of Urea from Semisolid Formulations Using a Multilayer Membrane System

A method for the determination of in vitro release of urea from semisolid formulations using a multilayer membrane system (MMS) has been developed. The artificial model membranes consisted of collodion as the matrix and glycerol as the hydrophilic acceptor phase. The method can be employed as a tool for comparison of in vitro release profile of semisolid formulations and, thus, can be used as a quality control procedure for assuring lot-to-lot uniformity.

Role of cardiolipin in the functioning of mitochonbrial L-glycerol-3-phosphate dehydrogenase

Adriamycin was used in situ, in isolated liver mitochondria of hyperthyroid rats to study the role of cardiolipin in the functioning of FAD-linked L-glycerol-3-phosphate dehydrogenase. The apparent kinetic parameters of the reaction catalyzed by the enzyme were affected by adriamycin. The effect of adriamycin was dependent on the electron acceptor, suggesting the existence of distinct binding sites for hydrophobic and hydrophilic acceptors. Assuming a correlation between the two plateaus observed upon binding of adriamycin to the mitochondria and the penetration of the drug into the two leaflets of the inner membrane [Cheneval et al. (1985) J. Biol. Chem. 260, 13003–13007], we can deduce that cardiolipin in both leaflets influences predominantly the electron acceptor binding site(s).

Biosynthesis of D-alanyl-lipoteichoic acid by Lactobacillus casei: interchain transacylation of D-alanyl ester residues.

Lipoteichoic acid (LTA) from Lactobacillus casei contains poly(glycerophosphate) substituted with D-alanyl ester residues. The distribution of these residues in the in vitro-synthesized polymer is uniform. Esterification of LTA with D-alanine may occur in one of two modes: (i) addition at random or (ii) addition at a defined locus in the poly(glycerophosphate) chain followed by redistribution of the ester residues. A time-dependent transacylation of these residues from D-[14C]alanyl-lipophilic LTA to hydrophilic acceptor was observed. The hydrophilic acceptor was characterized as D-alanyl-hydrophilic LTA. This transacylation requires neither ATP nor the D-alanine incorporation system, i.e., the D-alanine activating enzyme and D-alanine:membrane acceptor ligase. No evidence for an enzyme-catalyzed transacylation reaction was observed. We propose that this process of transacylation may be responsible for the redistribution of D-alanyl residues after esterification to the poly(glycerophosphate). As a result, it is difficult to distinguish between these proposed modes of addition.

Studies on electron transport associated with photosystem I. III. The reduction sites of various hill oxidants in the photosynthetic electron transport system

1. 1. HgCl 2 treatment of chloroplasts was effective in inducing an inhibition of 2,6-dichlorophenolindophenol (DCIP)-Hill activity in chloroplasts from several higher plants. 2. 2. The Hill reaction with various electron acceptors having a relatively high redox potential was severely, but not completely, inhibited by the HgCl 2 treatment of spinach chloroplasts. The surviving Hill activity in HgCl 2-treated chloroplasts was somewhat higher with lipophilic electron acceptors ( e.g. 2,5-dimethylbenzoquinone) than with hydrophilic acceptors ( e.g. DCIP). 3. 3. DCIP photoreduction in Euglena chloroplasts, sonicated spinach chloroplasts, or Photosystem II particles was highly resistant to the HgCl 2 treatment. 4. 4. The HgCl 2-insensitive part of the Hill activity showed an optimum at a more acidic pH and required higher concentrations of the electron acceptors for the maximum activity, as compared with the HgCl 2-sensitive part of the activity. 5. 5. A high concentration of dibromothymoquinone was effective in restoring the DCIP-Hill reaction activity in HgCl 2-treated chloroplasts. 6. 6. The results obtained indicate that the electron acceptors tested predominantly receive electrons at the reducing side of Photosystem I.

Properties of photoreductions by Photosystem II in isolated chloroplasts. An energy-conserving step in the photoreduction of benzoquinones by Photosystem II in the presence of dibromothymoquinone

Dibromothymoquinone has been used to block photosynthetic electron flow in chloroplasts between Photosystem I and II. The inhibition by dibromothymoquinone of electron flow and of coupled ATP formation in photoreductions by Photosystem I is reversed by the addition of plastoquinone, but not of other substituted benzoquinones. Because dibromothymoquinone does not permit electron flow from water through Photosystem I, Hill reactions in the presence of dibromothymoquinone are attributed to photoreductions by Photosystem II. The photoreduction of p-benzoquinone and 2,6-dimethylbenzoquinone in the presence of dibromothymoquinone is coupled to ATP formation with an ATP e 2 ratio of 0.3. Both photoreductions are stimulated by the addition of uncouplers. Ferricyanide photoreduction in the presence of dibromothymoquinone has a P e 2 ratio of only 0.16 and is not stimulated by an uncoupler. It is concluded that photoreductions by Photosystem II include an energy-conserving step and that lipophilic and hydrophilic acceptors are reduced on different sides of the membrane.

Electron transport and photophosphorylation in chloroplasts as a function of the electron acceptor. II. Acceptor-specific inhibition by KCN

1. 1. Dark pretreatment of chloroplasts with high concentrations of KCN in the presence of a trace of ferricyanide completely blocks subsequent transfer of electrons from water to hydrophilic acceptors such as ferricyanide and methylviologen. In the KCN-treated chloroplasts there is still a largely uninhibited electron flow from water to lipophilic oxidants such as p-benzoquinonediimide (oxidized p-phenylenediamine), duroquinonediimide (oxidized diaminodurene) and 2,5-dimethyl- p-benzoquinone. The cyanide-insensitive electron transport supports phosphorylation with a P/ e 2 ratio of 0.3 to 0.4. It is concluded (a) that these lipophilic oxidants can accept electrons from an unknown intermediate carrier, X, which precedes the KCN-inhibition site and is inaccessible to hydrophilic oxidants, and (b) that a phosphorylation site is associated with the electron pathway H 2O→X. 2. 2. Electron transport from diaminodurene to methylviologen and the associated phosphorylation are both inhibited by KCN. The same is true of cyclic photophosphorylation reactions catalyzed by diaminodurene, reduced dichlorophenolindophenol, pyocyanine, and low concentrations of N-methylphenazonium methosulfate. However, cyclic photophosphorylation can be largely restored by high concentrations of PMS. 3. 3. Isolated plastocyanin reacts readily with high concentrations of KCN (> 10 mM) but only at the relatively high pH values (> 7.5) required for effective KCN treatment of chloroplasts. It is suggested that this copper protein is the site of KCN inhibition in chloroplasts. 4. 4. Photoreduction of p-benzoquinonediimide is extremely sensitive to Photosystem II inhibitors, such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea, and the inhibition is completely independent of light intensity. In contrast, although the reduction of ferricyanide is almost equally sensitive at very low light intensities, the sensitivity decreases as the light intensity increases. It is suggested that the lipophilic reduction site, X, may be located close to Photosystem II.