Nanostructured Molecular Packing of Polymer Films Formed on Water Surfaces.

In this study, we examined the nanostructured molecular packing and orientations of poly[[N,N'-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)] (P(NDI2OD-T2)) films formed on water for the application of nanotechnology-based organic electronic devices. First, the nanoscale molecule-substrate interaction between the polymer and water was modulated by controlling the alkyl side chain length in NDI-based copolymers. Increasing alkyl side chain lengths induced a nanomorphological transition from face-on to edge-on orientation, confirmed by molecular dynamics simulations revealing nanostructural behavior. Second, the nanoscale intermolecular interactions of P(NDI2OD-T2) were controlled by varying the volume ratio of the high-boiling-point additive solvent in the binary solvent blends. As the additive solvent ratio increased, the nanostructured molecular orientation of the P(NDI2OD-T2) films on water changed remarkably from edge-on to bimodal with more face-on crystallites, thereby affecting charge transport. Our finding provides essential insights for precise nanoscale morphological control on water substrates, enabling the formation of high-performance polymer films for organic electronic devices.

Construction of a shuttle vector based on the small cryptic plasmid pJY33 from Weissella cibaria 33.

A cryptic plasmid, pJY33, from Weissella cibaria 33 was characterized. pJY33 was 2365 bp in size with a GC content of 41.27% and contained two putative open reading frames (ORFs). orf1 encoded a putative hypothetical protein of 134 amino acids. orf2 was 849 bp in size, and its putative translation product exhibited 87% identity with a replication initiation factor from a plasmid from W. cibaria KLC140. A Weissella-Escherichia coli shuttle vector, pJY33E (6.5 kb, Em(r)), was constructed by ligation of pJY33 with pBluescript II SK(-) and an erythromycin resistance gene (Em(r)). pJY33E replicated in Lactococcus lactis, Leuconostoc citreum, Lactobacillus brevis, Lactobacillus plantarum, and Weissella confusa. A single-stranded DNA intermediate was detected from Lb. brevis 2.14 harbouring pJY33E, providing evidence for rolling-circle replication of pJY33. Most Lb. brevis 2.14 cells (85.9%) retained pJY33E after one week of daily culturing in MRS broth without Em. An aga gene encoding α-galactosidase (α-Gal) from Leuconostoc mesenteroides was successfully expressed in Lb. brevis 2.14 using pJY33E, and the highest level of α-Gal activity (36.13 U/mg protein) was observed when cells were grown on melibiose.

Improved photovoltaic properties of polymer solar cells with a phenyl compound as an additive.

A phenyl compound with electron withdrawing substituents, 3-fluoro-4-cyanophenol (FCP), was used as an additive in polymer solar cells with a P3HT [poly(3-hexyl thiophene)]:PCBM [[6,6]-phenyl-C61-butyric acid methyl ester] blend film. Under simulated solar illumination of AM 1.5 (100 mW/cm2), the devices fabricated using a P3HT:PCBM (1:0.9 w:w) layer blended with 5 wt% of FCP achieved an enhanced power conversion efficiency (PCE) of 4.8% due to the improved short circuit current and fill factor, as compared to reference cells with PCE = 4.1%. UV-visible absorption spectra, X-ray measurements and carrier mobility studies revealed that FCP facilitated the ordering of the P3HT chains, resulting in higher absorbance, larger crystal size, closer packing and enhanced hole mobility.

Enhanced performance of polymer solar cells with a fluorocyanophenyl compound as an additive.

The efficiency of polymer solar cells (PSCs) with P3HT [poly(3-hexyl thiophene)]:PC61BM [[6,6]-phenyl C61-butyric acid methyl ester] blend film was improved by the incorporation of a fluorocyanophenyl compound, 3,4,5,6-tetrafluorophthalonitrile (TFP), as an additive. When the amount of TFTadditive was 5 wt% based on the total amount of P3HT and PC61BM, the highest efficiency was achieved. The annealed PSC with 5 wt% TFP had a power conversion efficiency of 4.45% compared with that (3.57%) of the reference cell without the additive, which corresponds to an increase of about 18.7% in the efficiency due to an enhancement in the short circuit current (J(sc)). A seriese of measurements such as UV-visible absorption spectroscopy, X-ray measurements, atomic force microscopic images and incident photon to current conversion efficiency (IPCE) spectra revealed that the increased J(sc) in the PSC with P3HT:PC61BM:TFP blend film was due to an improvement in both exciton generation and charge transport efficiency, resulting from higher absorbance, larger crystal size and more effective phase separation.

Characterization of a glutamate decarboxylase (GAD) gene from Lactobacillus zymae.

Lactic acid bacteria (LAB) were isolated from Kimchi, a Korean traditional fermented vegetable food. LAB accumulating GABA (γ-aminobutyric acid) in the culture media were screened by TLC analysis. One isolate, GU240, produced the highest amount of GABA among the 3,000 isolates and identified as a Lactobacillus zymae strain. Glutamate decarboxylase (GAD) gene was cloned and over-expressed in E. coli BL21(DE3) using pET26b(+). The recombinant GAD was purified by using a Ni-NTA column. Its size was 53 kDa by SDS-PAGE. Maximum GAD activity was at pH 4.5 and 41 °C and the activity was dependent on pyridoxal 5'-phosphate. Km and Vmax of LzGAD were 1.7 mM and 0.01 mM/min, respectively, when glutamate was used as a substrate.

A synergistic effect of herb and acupuncture on the methamphetamine.

Background: Herbal medicine Ja-Geum-Jeong (JGJ) has been used for the treatment of detoxification in Eastern Asia. However, the mechanisms involved are not clearly defined. The purpose of the present study was to investigate if herb medication inhibits Methamphetamine (METH)'s reinforcing effect and also examined if a combination of herb medication and acupuncture produces a synergistic effect on METH. Methods: Male Sprague-Dawley rats were given acute METH intraperitoneally and the locomotor activity and ultrasonic vocalization (USV) calls were measured. Rats were administered JGJ orally and acupuncture was given at HT7 or SI5. Monosodium glutamate (MSG) and gamma-aminobutyric acid (GABA) agonists were injected into the Central amygdala (CeA) to investigate a possible neuroscientific mechanism. Tyrosine hydroxylase (TH) and fast scan cyclic voltammetry (FSCV) were measured to immunohistochemically and electrically confirm the behavioral data. Results: Locomotor activity and USV calls were increased by METH (P < 0.05) and these increases were inhibited by JGJ (P < 0.05). Also, JGJ had no effect on the normal group given saline, and acupuncture at SI5 acupoint, but not at HT7 acupoint, produced a synergistic effect when combined with JGJ (P < 0.05). The JGJ's inhibition was blocked by the inactivation of CeA (P < 0.05), and MSG mimicked JGJ (P < 0.05). TH and FSCV measures showed the same pattern with the behavioral data (P < 0.05). Conclusion: Results of the present study suggest that JGJ had inhibitory effects on the METH which was mediated through the activation of CeA and that combination of acupuncture and herb produced synergistic effect.

Inverted polymer solar cells with an ultrathin lithium fluoride buffer layer.

An ultrathin lithium fluoride (LiF) buffer layer was applied to inverted polymer solar cells with P3HT [poly(3-hexylthiophene)]:PCBM [[6,6]-phenyl C61-butyric acid methyl ester] blend films. By inserting the LiF layer between the transparent electrode and the P3HT:PCBM blend film, all parameters, including the short-circuit current, the open-circuit voltage and the fill factor, were enhanced compared to those of a reference cell without the LiF layer. The power conversion efficiency of the device with the LiF layer was thereby improved by more than 300% relative to the reference cell.

Improvement of photovoltaic properties by addition of a perylene compound in P3HT:PCBM BHJ system.

The synthesized n-type perylene derivative, N,N'-bis-(4-bromophenyl)-1,6,7,12-tetrakis(4-n-butoxy-phenoxy)-3,4,9,10-perylene tetracarboxdiimide (PIBr), was applied as an additive to polymer solar cells (PSCs) with P3HT [poly(3-hexylthiophene)]:PCBM [[6,6]-phenyl C61-butyric acid methyl ester] blend films. Without post thermal annealing, a considerable improvement of about 98% in power conversion efficiency was achieved by the addition of 1 wt% PIBr into a P3HT:PCBM layer, when compared with that of reference cell without the additive. The results, in combination with relevant data from UV-Vis. absorption, photoluminescence, X-ray measurements and carrier mobility studies, revealed that the addition of the perylene compound within active layer contributed to more effective charge transfer and enhanced electron mobility.

Efficient inverted bulk heterojunction photovoltaic devices using a transparent polymeric interfacial buffer layer with C60 pendant and UV curable groups.

We demonstrate the synthesis of a transparent, polymeric n-type material (M1) consisting of C60 pendant and UV curable groups in side chains. This material (M1) is employed as a polymeric n-type interfacial buffer layer for an efficient inverted bulk heterojunction (BHJ) photovoltaic device based on regioregular poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester (P3HT:PC61BM) active layer. Under simulated solar illumination of AM 1.5G (100 mW/cm2), the highest efficient devices fabricated with a configuration of ITO/interfacial buffer layer (M1,10 nm)/P3HT:PC61BM (1:0.9 w:w) (120 nm)/PEDOT:PSS (30 nm)/Ag (100 nm) achieve an average power conversion efficiency PCE of 2.16%, with short-circuit current J(SC) = 6.70 mA/cm2, fill factor FF = 54.2%, and open-circuit voltage V(OC) = 0.60 V. This result is comparable to the inverted BHJ photovoltaic devices fabricated with Cs2CO3, one of widely used as a buffer layer. The synthesized M1 have thus proven to be promising polymeric interfacial buffer layer for high efficient BHJ photovoltaic devices.

Effects of isoflurane anesthesia on addictive behaviors in rats.

RATIONALE: Recently, it has been suggested that isoflurane might reduce dopamine release from rat midbrain dopaminergic neurons, the neurobiological substrate implicated in the reinforcing effects of abused drugs and nondrug rewards. However, little is known about effects of isoflurane on neurobehavioral activity associated with chronic exposure to psychoactive substances. OBJECTIVE: The present study was designed to investigate the effects of isoflurane on cocaine-reinforced behavior. Using behavioral paradigm in rats, we evaluated the effects of isoflurane on cocaine self-administration under fixed ratio (FR) and progressive ratio (PR) schedules of reinforcement. We also tested the effects of isoflurane on lever responding by nondrug reinforcers (sucrose and food) in drug-naive rats to control for the nonselective effects of isoflurane on cocaine- and nicotine-taking behavior. To further assess the ability of isoflurane to modulate the motivation for taking a drug, we evaluated the effects of isoflurane on nicotine self-administration. Using different groups of rats, the effects of isoflurane on the locomotor activity induced by a single intraperitoneal injection of cocaine (15 mg/kg) were also examined. RESULTS: Isoflurane significantly suppressed the self-administration of cocaine and nicotine without affecting food consumption. Unlike food-reinforced responding, responding for sucrose reinforcement was decreased by isoflurane. Isoflurane reduced breaking points under a PR schedule of reinforcement in a dose-dependent manner, indicating its efficacy in decreasing the incentive value of cocaine. Isoflurane also attenuated acute cocaine-induced hyperlocomotion. CONCLUSIONS: The results provided evidence that isoflurane decreases cocaine- and nicotine-reinforced responses, while isoflurane effect is not selective for cocaine- and nicotine-maintained responding. These results suggest that isoflurane inhibitions of cocaine- and nicotine-maintenance responses may be related to decreased effects of dopamine, and further investigation will need to elucidate this relationship.

Synthesis and electro-optical properties of carbazole-substituted pyrene derivatives.

Mono and dicarbazole-substituted pyrene derivatives, 9H-carbazol-9-ylpyrene (MCzP) and 1,6-di(9H-carbazol-9-yl)pyrene (DCzP), with dual-purpose function as a blue emitting and charge transporting layer in organic light emitting diodes, were synthesized and characterized. These series of molecules consisted of an electron donating (D) carbazole and an electron accepting (A) pyrene in D-A and D-A-D shapes. Non-doped blue electroluminescent devices with the configurations of ITO (150 nm)/alpha-NPD (30 nm)/DCzP (40 nm)/LiF (1 nm)/Al (150 nm) (D1) and ITO (150 nm)/2-TNATA (15 nm)/alpha-NPD (20 nm)/DCzP (40 nm)/BCP (15 nm)/Alq3 (10 nm)/LiF (1 nm)/Al (120 nm) (D2) were fabricated. D1 and D2 devices showed blue emission at 492 nm and 488 nm, and maximum luminance of 840 and 7560 cd/m2 obtained at 13 V and 15 V, respectively.

Social isolation-related depression accelerates ethanol intake via microglia-derived neuroinflammation.

Social isolation is common in modern society and is a contributor to depressive disorders. People with depression are highly vulnerable to alcohol use, and abusive alcohol consumption is a well-known obstacle to treating depressive disorders. Using a mouse model involving isolation stress (IS) and/or ethanol intake, we investigated the mutual influence between IS-derived depressive and ethanol-seeking behaviors along with the underlying mechanisms. IS increased ethanol craving, which robustly exacerbated depressive-like behaviors. Ethanol intake activated the mesolimbic dopaminergic system, as evidenced by dopamine/tyrosine hydroxylase double-positive signals in the ventral tegmental area and c-Fos activity in the nucleus accumbens. IS-induced ethanol intake also reduced serotonergic activity, via microglial hyperactivation in raphe nuclei, that was notably attenuated by a microglial inhibitor (minocycline). Our study demonstrated that microglial activation is a key mediator in the vicious cycle between depression and alcohol consumption. We also propose that dopaminergic reward might be involved in this pathogenicity.

MS-5, a Naphthalene Derivative, Induces the Apoptosis of an Ovarian Cancer Cell CAOV-3 by Interfering with the Reactive Oxygen Species Generation.

Reactive oxygen species (ROS) are widely generated in biological processes such as normal metabolism and response to xenobiotic exposure. While ROS can be beneficial or harmful to cells and tissues, generation of ROS by diverse anti-cancer drugs or phytochemicals plays an important role in the induction of apoptosis. We recently identified a derivative of naphthalene, MS-5, that induces apoptosis of an ovarian cell, CAOV-3. Interestingly, MS-5 induced apoptosis by down-regulating the ROS. Cell viability was evaluated by water-soluble tetrazolium salt (WST-1) assay. Apoptosis was evaluated by flow cytometry analysis. Intracellular ROS (H2O2), mitochondrial superoxide, mitochondrial membrane potential (MMP) and effect on cycle were determined by flow cytometry. Protein expression was assessed by western blotting. The level of ATP was measured using ATP Colorimetric/Fluorometric Assay kit. MS-5 inhibited growth of ovarian cancer cell lines, CAOV-3, in a concentration- and time-dependent manner. MS-5 also induced G1 cell cycle arrest in CAOV-3 cells, while MS-5 decreased intracellular ROS generation. In addition, cells treated with MS-5 showed the decrease in MMP and ATP production. In this study, we found that treatment with MS-5 in CAOV-3 cells induced apoptosis but decreased ROS level. We suspect that MS-5 might interfere with the minimum requirements of ROS for survival. These perturbations appear to be concentration-dependent, suggesting that MS-5 may induce apoptosis by interfering with ROS generation. We propose that MS-5 may be a potent therapeutic agent for inducing apoptosis in ovarian cancer cell through regulation of ROS.

Expression of alpha-galactosidase gene from Leuconostoc mesenteroides SY1 in Leuconostoc citreum.

A 2.5 kb aga gene encoding alpha-galactosidase (alpha- Gal) from Leuconostoc mesenteroides SY1 was cloned into pSJE, an E. coli-Leuconostoc shuttle vector. The recombinant plasmid, pSJEaga, was introduced into Leuconostoc citreum KCTC3526 (ATCC49370) by electroporation. Transcription level of aga was the highest in cells grown on raffinose (1%, w/v) followed by cells grown on galactose, melibiose, fructose, glucose, and sucrose. Western blot using antibodies against alpha-Gal showed similar results to slot-blot results and enzyme activity measurements. All the results indicated that the heterologous aga was successfully expressed in L. citreum and its transcription was under the carbon catabolite repression (CCR).

Cloning of fibrinolytic enzyme gene from Bacillus subtilis isolated from Cheonggukjang and its expression in protease-deficient Bacillus subtilis strains.

Bacillus subtilis CH3-5 was isolated from cheonggukjang prepared according to traditional methods. CH3-5 secreted at least four different fibrinolytic proteases (63, 47, 29, and 20 kDa) into the culture medium. A fibrinolytic enzyme gene, aprE2, encoding a 29 kDa enzyme was cloned from the genomic DNA of CH3-5, and the DNA sequence determined. aprE2 was overexpressed in heterologous B. subtilis strains deficient in extracellular proteases using a E. coli-Bacillus shuttle vector. A 29 kDa AprE2 band was observed and AprE2 seemed to exhibit higher activities towards fibrin rather than casein.

Characterization of paraplantaricin C7, a novel bacteriocin produced by Lactobacillus paraplantarum C7 isolated from kimchi.

A Lactobacillus paraplantarum strain producing a bacteriocin was isolated from kimchi using the spot-on-the lawn method and named L. paraplantarum C7. The bacteriocin, paraplantaricin C7, was found to inhibit certain Lactobacillus strains, including L. plantarum, L. pentosus, and L. delbrueckii subsp. lactis. It also inhibited Enterococcus faecalis, yet did not inhibit most of the other LAB (lactic acid bacteria) tested. The maximum level of paraplantaricin C7 activity was observed under the culture conditions of 25 degrees C and a constant pH of 4.5. Paraplantaricin C7 retained 90% of its activity after 10 min of treatment at 100 degrees C and remained stable within a pH range of 2-8. Based on a culture supernatant, paraplantaricin C7 was purified by DEAE-Sephacel column chromatography and C18 reverse-phase HPLC. SDS-PAGE and activity staining were then conducted using the purified paraplantaricin C7, and its molecular mass determined to be about 3,800 Da. The 28 N-terminal amino acids from the purified paraplantaricin C7 were determined, and the structural gene encoding paraplantaricin C7, ppnC7, was cloned by PCR using degenerate primers based on the N-terminal amino acid sequence. The nucleotide sequences for ppnC7 and other neighboring orfs exhibited a limited homology to the previously reported plantaricin operon genes. Paraplantaricin C7 is a novel type II bacteriocin containing a double glycine leader sequence.

Isolation and Characterization of Some Promoter Sequences from Leuconostoc mesenteroides SY2 Isolated from Kimchi.

Some promoters were isolated and characterized from the genome of Leuconostoc mesenteroides SY2, an isolate from kimchi, a Korean traditional fermented vegetable. Chromosomal DNA of L. mesenteroides SY2 was digested with Sau3AI and ligated with BamHI-cut pBV5030, a promoter screening vector containing a promoterless cat-86. Among E. coli transformants (TFs) resistant against Cm (chloramphenicol), 17 were able to grow in the presence of 1,000 µg/ml Cm and their inserts were sequenced. Transcription start sites were examined for three putative promoters (P04C, P25C, and P33C) by primer extension. Four putative promoters were inserted upstream of a promoterless α-amylase reporter gene in pJY15α. α-Amylase activities of E. coli TFs containing pJY15α (control, no promoter), pJY03α (pJY15α with P03C), pJY04α (with P04C), pJY25α (with P25C), and pJY33α (with P33C) were 66.9, 78.7, 122.1, 70.8, and 99.3 U, respectively. Cells harboring pJY04α showed 1.8 times higher activity than the control. Some promoters characterized in this study might be useful for construction of foodgrade expression vectors for Leuconostoc sp. and related lactic acid bacteria.

Bioinspired Transparent Laminated Composite Film for Flexible Green Optoelectronics.

Herein, we report a new version of a bioinspired chitin nanofiber (ChNF) transparent laminated composite film (HCLaminate) made of siloxane hybrid materials (hybrimers) reinforced with ChNFs, which mimics the nanofiber-matrix structure of hierarchical biocomposites. Our HCLaminate is produced via vacuum bag compressing and subsequent UV-curing of the matrix resin-impregnated ChNF transparent paper (ChNF paper). It is worthwhile to note that this new type of ChNF-based transparent substrate film retains the strengths of the original ChNF paper and compensates for ChNF paper's drawbacks as a flexible transparent substrate. As a result, compared with high-performance synthetic plastic films, such as poly(ethylene terephthalate), poly(ether sulfone), poly(ethylene naphthalate), and polyimide, our HCLaminate is characterized to exhibit extremely smooth surface topography, outstanding optical clarity, high elastic modulus, high dimensional stability, etc. To prove our HCLaminate as a substrate film, we use it to fabricate flexible perovskite solar cells and a touch-screen panel. As far as we know, this work is the first to demonstrate flexible optoelectronics, such as flexible perovskite solar cells and a touch-screen panel, actually fabricated on a composite film made of ChNF. Given its desirable macroscopic properties, we envision our HCLaminate being utilized as a transparent substrate film for flexible green optoelectronics.

Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate.

Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

Characterization of Glutamate Decarboxylase (GAD) from Lactobacillus sakei A156 Isolated from Jeot-gal.

A gamma-aminobutyric acid (GABA)-producing microorganism was isolated from jeot-gal (anchovy), a Korean fermented seafood. The isolate, A156, produced GABA profusely when incubated in MRS broth with monosodium glutamate (3% (w/v)) at 37°C for 48 h. A156 was identified as Lactobacillus sakei by 16S rRNA gene sequencing. The GABA conversion yield was 86% as determined by GABase enzyme assay. The gadB gene encoding glutamate decarboxylase (GAD) was cloned by PCR. gadC encoding a glutamate/GABA antiporter was located immediately upstream of gadB. The operon structure of gadCB was confirmed by RT-PCR. gadB was overexpressed in Escherichia coli BL21(DE3) and recombinant GAD was purified. The purified GAD was 54.4 kDa in size by SDS-PAGE. Maximum GAD activity was observed at pH 5.0 and 55°C and the activity was dependent on pyridoxal 5'-phosphate. The Km and Vmax of GAD were 0.045 mM and 0.011 mM/min, respectively, when glutamate was used as the substrate.