26 research outputs found
Biochemical Compositions and Biological Activities of Extracts from 3 Species of Korean Pine Needles
Abstract Crude extracts of pine needles have long been used as a health-food and for cosmetics. In this study, we determined the biochemical composition and biological activities of extracts from three pine species: red pine (RP, Pinus densiflora S et Z), Keumkang pine (KP, Pinus densiflora for. erecta) and sea pine (SP, Pinus thunbergii). The SP extract had the highest levels of moisture, ash, crude protein, and lipids based on the dry weight. The SP extract also had the highest level of polyunsaturated fatty acids (PUFAs). The SP extract had much more β-pinene, β-caryophyllene, and germacrene-D than extracts from the other species. Total phenolic content was the highest in the 100% ethanol extract of SP, and the 50% ethanol extract of SP had the highest DPPH radical scavenging activity. The SP extract had the greatest antimicrobial effect. These results indicate that SP has the greatest potential as a natural antioxidant resource and raw material for cosmetic-goods
Self-assembled poly(4-vinylpyridine) as an interfacial layer for polymer solar cells : PVPy SAM as an interfacial layer
A nonconjugated polymer, poly(4‐vinylpyridine) (PVPy), is applied to polymer solar cells (PSCs) as an interfacial layer (IFL) either inverted or conventional type PSCs. The Kelvin probe microscopy measurements support the formation of favorable interface dipole at the cathode interface, indicating the reduction of an electron collection barrier from the active layer to the cathode. Inverted type PSC with PVPy as an IFL demonstrate the power conversion efficiency (PCE) of 3.20%, (open circuit voltage [V\ua0oc] = 0.61 V, short circuit current [J\ua0sc] = 8.68 mA/cm2, fill factor [FF] = 59.4%), which is better than the device without interlayer (PCE = 2.95%,\ua0V\ua0oc\ua0= 0.60 V,\ua0J\ua0sc\ua0= 8.11 mA/cm2, FF = 60.6%). Most increase in the PCE of the devices with interlayer is resulted from enhancement of the\ua0J\ua0sc. This is due to that the reduction of an electron collection barrier at the cathode interface. Conventional type PSC with PVPy (3.51%) at the cathode interface also exhibits better the PCE compared to that of the device without interlayer (2.88%)
Genomics-based Sensitive and Specific Novel Primers for Simultaneous Detection of Burkholderia glumae and Burkholderia gladioli in Rice Seeds
Panicle blight and seed rot disease caused mainly by Burkholderia glumae and Burkholderia gladioli is threatening rice cultivation worldwide. The bacteria have been reported as seed-borne pathogens from rice. Accurate detection of both pathogens on the seeds is very important for limiting the disease dissemination. Novel primer pairs targeting specific molecular markers were developed for the robust detection of B. glumae and B. gladioli. The designed primers were specific in detecting the target species with no apparent cross-reactions with other related Burkholderia species at the expected product size. Both primer pairs displayed a high degree of sensitivity for detection of B. glumae and B. gladioli separately in monoplex PCR or simultaneously in duplex PCR from both extracted gDNA and directly preheated bacterial cell suspensions. Limit of detection was as low as 0.1 ng of gDNA of both species and 3.86 × 10² cells for B. glumae and 5.85 × 10² cells for B. gladioli. On inoculated rice seeds, the designed primers could separately or simultaneously detect B. glumae and B. gladioli with a detection limit as low as 1.86 × 10³ cells per rice seed for B. glumae and 1.04 × 10⁴ cells per rice seed of B. gladioli. The novel primers maybe valuable as a more sensitive, specific, and robust tool for the efficient simultaneous detection of B. glumae and B. gladioli on rice seeds, which is important in combating rice panicle blight and seed rot by early detection and confirmation of the dissemination of pathogen-free rice seeds
The Roles of Two hfq Genes in the Virulence and Stress Resistance of Burkholderia glumae
The Hfq protein is a global small RNA chaperone that interacts with regulatory bacterial small RNAs (sRNA) and plays a role in the post-transcriptional regulation of gene expression. The roles of Hfq in the virulence and pathogenicity of several infectious bacteria have been reported. This study was conducted to elucidate the functions of two hfq genes in Burkholderia glumae, a causal agent of rice grain rot. Therefore, mutant strains of the rice-pathogenic B. glumae BGR1, targeting each of the two hfq genes, as well as the double defective mutant were constructed and tested for several phenotypic characteristics. Bacterial swarming motility, toxoflavin production, virulence in rice, siderophore production, sensitivity to H₂O₂, and lipase production assays were conducted to compare the mutant strains with the wild-type B. glumae BGR1 and complementation strains. The hfq1 gene showed more influence on bacterial motility and toxoflavin production than the hfq2 gene. Both genes were involved in the full virulence of B. glumae in rice plants. Other biochemical characteristics such as siderophore production and sensitivity to H₂O₂ induced oxidative stress were also found to be regulated by the hfq1 gene. However, lipase activity was shown to be unassociated with both tested genes. To the best of our knowledge, this is the first study to elucidate the functions of two hfq genes in B. glumae. Identification of virulence-related factors in B. glumae will facilitate the development of efficient control measures
Effect of self-assembled monolayer treated ZnO on the photovoltaic properties of inverted polymer solar cells
Inverted bulk hetero-junction polymer solar cells (iPSC) composed of P3HT/PC61BM blends on the ZnO modified with benzoic acid derivatives-based self-assembled monolayers (SAM) are fabricated. Compared with the device using the pristine ZnO, the devices with ZnO surface modified SAMs derived from benzoic acid such as 4-(diphenylamino)benzoic acid (DPA-BA) and 4-(9H-carbazol-9-yl)benzoic acid (Cz-BA) as an electron transporting layer show improved the performances. It is mainly attributed to the favorable interface dipole at the interface between ZnO and the active layer, the eective passivation of the ZnO surface traps, decrease of the work function and facilitating transport of electron from PCBM to ITO electrode. The power conversion eciency (PCE) of iPSCs based on DPA-BA and Cz-BA treated ZnO reaches 2.78 and 2.88%, respectively, while the PCE of the device based on untreated ZnO is 2.49%. The open circuit voltage values (VocVoc) of the devices with bare ZnO and SAM treated ZnO are not much different. Whereas, higher the fill factor (FF) and lower the series resistance (RsRs) are obtained in the devices with SAMs modification
Effect of Polyelectrolyte Electron Collection Layer Counteranion on the Properties of Polymer Solar Cells
Polyviologen (PV) derivatives are
known materials used for adjusting
the work function (WF) of cathodes by reducing the electron injection/collection
barrier at the cathode interface. To tune and improve device performance,
we introduce different types of counteranions (CAs), such as bromide,
tetrafluoroborate, and tetraphenylborate, to a PV derivative. The
effective WF of the Al cathode is shown to depend on the size of the
CA, indicating that a Schottky barrier can be modulated by the size
of the CA. Through the increased size of the CA from bromide to tetraphenylborate,
the effective WF of the Al cathode is gradually decreased, indicating
a decreased Schottky barrier at the cathode interface. In addition,
the change of the power conversion efficiency (PCE) and the short
circuit current (<i>J</i><sub>sc</sub>) value show good
correlation with the change of the WF of the cathode, signifying the
typical transition from a Schottky to an Ohmic contact. The turn-on
electric field of the electron-only device without PV was 0.21 MV/cm,
which is dramatically higher than those of devices with PV-X (0.07
MV/cm for PV-Br, 0.06 MV/cm for PV-BF<sub>4</sub>, and 0.05 MV/cm
for PV-BPh<sub>4</sub>) This is also coincident with a decrease in
the Schottky barrier at the cathode interface. The device ITO/PEDOT/P3HT:PCBM/PV/Al,
with a thin layer of PV derivative and tetraphenylborate CA as the
cathode buffer layer, has the highest PCE of 4.02%, an open circuit
voltage of 0.64 V, a <i>J</i><sub>sc</sub> of 11.6 mA/cm<sup>2</sup>, and a fill factor of 53.0%. Our results show that it is
possible to improve the performance of polymer solar cells by choosing
different types of CAs in PV derivatives without complicated synthesis
and to refine the electron injection/collection barrier height at
the cathode interface
Low-Temperature Solution-Processed Flexible Organic Solar Cells with PFN/AgNWs Cathode
We report on highly efficient flexible inverted organic solar cells (IOSCs) fabricated by low-temperature solution process on polyethylene terephthalate (PET) substrate. In general, IOSCs have been required to use an annealed (>200 degrees C) zinc oxide (ZnO) as an electron transport layer. However, any twisting of the flexible substrate during heat treatment leads to poor device performance. To overcome this issue, we developed a novel low temperature process for flexible IOSCs using an alcohol-/water-soluble conjugated polymer, namely poly [(9,9-bis(3'-(N, N-dimethylamino) propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] (PFN) instead of the ZnO. Using this low-temperature process, we successfully demonstrate highly efficient flexible IOSCs that are proven to be capable of the power conversion efficiency (PCE) of 6.17% which retain 96% of its efficiency at a bending radius of R approximate to 5 mm or less. To the best of our knowledge, this PCE 6.17% is the best result among the reported values so far for flexible OSCs fabricated on PET substrate. (C) 2015 Elsevier Ltd. All rights reserved.close0
Standard-based comprehensive detection of adverse drug reaction signals from nursing statements and laboratory results in electronic health records
Objective. We propose 2 Medical Dictionary for Regulatory Activities-enabled pharmacovigilance algorithms, MetaLAB and MetaNurse, powered by a per-year meta-analysis technique and improved subject sampling strategy. Matrials and methods. This study developed 2 novel algorithms, MetaLAB for laboratory abnormalities and MetaNurse for standard nursing statements, as significantly improved versions of our previous electronic health record (EHR)-based pharmacovigilance method, called CLEAR. Adverse drug reaction (ADR) signals from 117 laboratory abnormalities and 1357 standard nursing statements for all precautionary drugs (n = 101) were comprehensively detected and validated against SIDER (Side Effect Resource) by MetaLAB and MetaNurse against 11 817 and 76 457 drug-ADR pairs, respectively. Results. We demonstrate that MetaLAB (area under the curve, AUC = 0.61 +/- 0.18) outperformed CLEAR (AUC = 0.55 +/- 0.06) when we applied the same 470 drug-event pairs as the gold standard, as in our previous research. Receiver operating characteristic curves for 101 precautionary terms in the Medical Dictionary for Regulatory Activities Preferred Terms were obtained for MetaLAB and MetaNurse (0.69 +/- 0.11; 0.62 +/- 0.07), which complemented each other in terms of ADR signal coverage. Novel ADR signals discovered by MetaLAB and MetaNurse were successfully validated against spontaneous reports in the US Food and Drug Administration Adverse Event Reporting System database. Discussion. The present study demonstrates the symbiosis of laboratory test results and nursing statements for ADR signal detection in terms of their system organ class coverage and performance profiles. Conclusion. Systematic discovery and evaluation of the wide spectrum of ADR signals using standard-based observational electronic health record data across many institutions will affect drug development and use, as well as postmarketing surveillance and regulation.OAIID:RECH_ACHV_DSTSH_NO:T201702032RECH_ACHV_FG:RR00200001ADJUST_YN:EMP_ID:A079621CITE_RATE:3.698DEPT_NM:의학과EMAIL:[email protected]_YN:YY
Amplitude and phase reconstruction of electron wave packets for probing ultrafast photoionization dynamics
Ultrafast atomic processes, such as excitation and ionization occurring on the femtosecond or shorter time scale, were explored by employing attosecond high-harmonic pulses. With the absorption of a suitable high-harmonic photon a He atom was ionized, or resonantly excited with further ionization by absorbing a number of infrared photons. The electron wave packets liberated by the two processes generated an interference containing the information on ultrafast atomic dynamics. The attosecond electron wave packet, including the phase, from the ground state was reconstructed first and, subsequently, that from the 1s3p state was retrieved by applying the holographic technique to the photoelectron spectra comprising the interference between the two ionization paths. The reconstructed electron wave packet revealed details of the ultrafast photoionization dynamics, such as the instantaneous two-photon ionization rate.Peer reviewed: YesNRC publication: N
Lewis acid-base adduct-type organic hole transport material for high performance and air-stable perovskite solar cells
Since hole transport materials (HTMs) play a significant role in enhancing the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs), which are the key factors for their commercialization, an effective design strategy is necessary for the potential HTMs in the current emerging field of PSCs. Here, we present a new class of HTM with pyridine as a central core with an extended pi-conjugated molecular structure with electron-donating blocks. We have systematically investigated its photophysical, thermal, electrochemical, and charge transport properties and found that 4,4'-(5,5'-(pyridine-2,6-diylbis(4,1-phenylene))bis(thiophene-5,2-diyl))bis (N,N-bis(4-methoxyphenyl)aniline) (PyThTPA) is a potential HTM candidate for making PSCs. The PyThTPA HTM-based PSC attained an average PCE of 16.57% with outstanding long-term durability of over 720 hrs with minimal reduction of its initial PCE and negligible hysteresis. This PSC performance was 34% higher than that of the state-of-the-art HTM, Spiro-OMeTAD with tris(pentafluorophenyl)borane (BCF). We speculate that the Lewis acid-base adduct (LABA) formation of pyridine in the HTM and BCF interacted with methylammonium lead iodide (MAPbI(3)), resulting in the MAPbI(3)/HTM interface becoming more selective for holes. This also enhanced the film uniformity and afforded a smoother morphology with improved hydrophobicity that further increased the long-term durability. Furthermore, the mobility and conductivity were increased for PyThTPA with BCF. To the best of our knowledge, this is the first report of pyridine being incorporated into the HTM with continuous pi-conjugation and with a high performance of nearly 17%. Overall, we believe that this approach will be an effective design strategy capable of enhancing the performance of PSCs with less hysteresis and improved long-term durability.11Nsciescopu