Synthesis and Transistor Properties of Asymmetric Oligothiophenes: Relationship between Molecular Structure and Device Performance

A series of three thiophene–naphthalene‐based asymmetric oligomers—5‐decyl‐2,2′:5′,2′′:5′′,2′′′‐quaterthiophene (DtT), 5‐decyl‐5′′‐(naphthalen‐2‐yl)‐2,2′:5′,2′′‐terthiophene (D3TN), and 5‐(4‐decylphenyl)‐5′‐(naphthalen‐2‐yl)‐2,2′‐bithiophene (DP2TN)—was synthesized by Suzuki cross‐coupling reactions. The long alkyl side chains improved both the solubility of the oligomers in solvents and their tendency to self‐assemble. UV/Vis absorption measurements suggested that DtT, D3TN, and DP2TN form H‐type aggregates with a face‐to‐face packing structure. In addition, the three oligomers were found to adopt vertically aligned crystalline structures in films deposited on substrates, as revealed by grazing‐incidence wide‐angle X‐ray scattering. These oligomers were used as the active layers of p‐type organic field‐effect transistors, and the resulting devices showed field‐effect mobilities of 3.3×10^?3 cm² V^?1 s^?1 for DtT, 1.6×10^?2 cm² V^?1 s^?1 for D3TN, and 3.7×10^?2 cm² V^?1 s^?1 for DP2TN. The differences in transistor performances were attributed to the degree of π overlap and the morphological differences determined by the molecular structures.     

An ab initio molecular fragment investigation of the electronic and conformational structure of formaldoxime

An ab initio molecular fragment study of formaldoxime is reported and compared with previous semiempirical and conventional ab initio studies.     

Simultaneous quantification of cycloserine and its prodrug acetylacetonylcycloserine in plasma and urine by high-performance liquid chromatography using ultraviolet absorbance and fluorescence after post-column derivatization

D-Cycloserine is a broad-spectrum antibiotic used with other antibiotics to treat various forms of tuberculosis. Its prodrug sodium (R)-4-[(1-methyl-3-oxo-1-butenyl)amino]-3-isoxazolidinone hemihydrate, developed for better aqueous stability and solubility, is combined with another broad-spectrum antibiotic, fludalanine. An ion-pair, reversed-phase high-performance liquid chromatographic assay has been developed to simultaneously detect cycloserine and its prodrug in plasma and urine. The prodrug is detected directly by ultraviolet absorbance and cycloserine by fluorescence following post-column derivatization.     

Rhamnogalacturonan II is a Toll-like receptor 4 agonist that inhibits tumor growth by activating dendritic cell-mediated CD8+ T cells

We evaluated the effectiveness of rhamnogalacturonan II (RG-II)-stimulated bone marrow-derived dendritic cells (BMDCs) vaccination on the induction of antitumor immunity in a mouse lymphoma model using EG7-lymphoma cells expressing ovalbumin (OVA). BMDCs treated with RG-II had an activated phenotype. RG-II induced interleukin (IL)-12, IL-1β, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) production during dendritic cell (DC) maturation. BMDCs stimulated with RG-II facilitate the proliferation of CD8⁺ T cells. Using BMDCs from the mice deficient in Toll-like receptors (TLRs), we revealed that RG-II activity is dependent on TLR4. RG-II showed a preventive effect of immunization with OVA-pulsed BMDCs against EG7 lymphoma. These results suggested that RG-II expedites the DC-based immune response through the TLR4 signaling pathway.     

Pellino1 promotes chronic inflammatory skin disease via keratinocyte hyperproliferation and induction of the T helper 17 response

Psoriasis is one of the most common immune-mediated chronic inflammatory skin diseases. However, little is known about the molecular mechanism underlying the immunological circuits that maintain innate and adaptive immune responses in established psoriasis. In this study, we found that the Pellino1 (Peli1) ubiquitin E3 ligase is activated by innate pattern-recognition receptors (PRRs), such as Toll-like receptors (TLRs), and is highly upregulated in human psoriatic skin lesions and murine psoriasis-like models. Increased Peli1 expression is strongly correlated with the immunopathogenesis of psoriasis by activating hyperproliferation of keratinocytes in the S and G2/M phases of the cell cycle and promoting chronic skin inflammation. Furthermore, Peli1-induced psoriasis-like lesions showed significant changes in the expression levels of several T helper 17 (Th17)-related cytokines, such as IL-17a, IL-21, IL-22, IL-23, and IL-24, indicating that overexpression of Peli1 resulted in the sequential engagement of the Th17 cell response. However, the overexpression of Peli1 in T cells was insufficient to trigger psoriasis, while T cells were indispensable for disease manifestation. In summary, our findings demonstrate that Peli1 is a critical cell cycle activator of innate immunity, which subsequently links Th17 cell immune responses to the psoriatic microenvironment.Subject terms: Chronic inflammation, Immunoproliferative disorders     

Inhibitory Effects of Selected Medicinal Plants on Bacterial Growth of Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to global public health due to its capacity of tolerate conventional antibiotics. Medicinal plants are traditionally used to treat infectious diseases caused by bacterial pathogens. In the present study, 16 medicinal plants were screened for antibacterial activities to preselect more effective species. Ethanol extracts of selected medicinal plants (Caesalpinia sappan L., Glycyrrhiza uralensis Fisch., Sanguisorba officinalis L., and Uncaria gambir Roxb) were partitioned successively with different solvents (n-hexane, chloroform, ethyl acetate, 1-butanol, and water). Disc diffusion assay and broth microdilution were performed to evaluate the antibacterial activities of plant extracts and fractions against Staphylococcus aureus strains. Furthermore, the cytotoxicity of the extracts and fractions was determined against the human hepatoma (HepG2) and human lung carcinoma (A549) cell lines using a trypan blue exclusion method. A few extracts and fractions showed significant inhibitory effects on the bacterial growth of all tested strains, including multidrug-resistance (MDR) clinical isolates. The ethyl acetate fraction of C. sappan had the most potent effects with minimum inhibitory/bactericidal concentrations (MIC/MBC) of 31.2/62.5 μg/mL and showed low cytotoxicity with over 90% cell viability in both cells. Our results suggest that medicinal plants have considerable potential as alternatives to conventional antibiotics.     

Microwave Accelerated Extraction and Capillary Electrophoresis Analysis of Berberine from the Cortices of Phellodendron Wilsonii and Phellodendron Amurense

Berberine is one of the most important bioactive compounds used in Chinese herbal drugs to evaluate the quality of the Phellodendron cortex. The cortices of Phellodendron wilsonii and Phellodendron amurense, extracted by using a microwave‐assisted process under a domestic microwave oven in methanol solvent and analyzed by capillary electrophoresis with the buffer solution of 82% 0.1 M aqueous sodium acetate and 18% MeOH (v/v), were demonstrated to be higher in extracting berberine contents and shorter in the process time than those extracted by using a reflux extraction in methanol solvent (for sample B, 2.27 ± 0.08% in 3 min vs. 1.92 ± 0.14% in 5 hrs, respectively). Therefore, the microwave‐assisted process for extraction of berberine is more efficient, rapid and convenient than the reflux extraction and can be used for the extraction of bioactive substances from the crude Chinese drugs.     

Non-enzymatic electrochemical CuO nanoflowers sensor for hydrogen peroxide detection

The electrocatalytic activity of a CuO flower-like nanostructured electrode was investigated in terms of its application to enzyme-less amperometric H₂O₂ sensors. The CuO nanoflowers film was directly formed by chemical oxidation of copper foil under hydrothermal condition and then used as active electrode material of non-enzymatic electrochemical sensors for H₂O₂ detection under alkaline conditions. The sensitivity of the sensor with CuO nanoflowers electrode was 88.4 μA/mM cm² with a linear response in the range from 4.25 × 10⁻⁵ to 4 × 10⁻² M and a detection limit of 0.167 μM (S/N = 3). Excellent electrocatalytic activity, large surface-to-volume ratio and efficient electron transport property of CuO nanoflowers electrode have enabled stable and highly sensitive performance for the non-enzymatic H₂O₂ sensor.     

A Raman Study of the Effect of Trivalent Lanthanide Ions on the Conformational Disorder in Acyl Chains of Phospholipid Bilayers

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Ion current calculations based on three dimensional Poisson-Nernst-Planck theory for a cyclic peptide nanotube

Ion current calculations based on Poisson-Nernst-Planck (PNP) theory are performed for a synthetic cyclic peptide nanotube that consists of eight or ten cyclo[(-L-Trp-D-Leu-)4] embedded in a lipid bilayer membrane to investigate the ion transport properties of the nanotube. To explore systems with arbitrary geometries, three-dimensional PNP theory is implemented using a finite difference method. The influence of dipolar lipid molecules on the ion currents is also examined by turning on or off the charges of the lipid dipoles in dipalmitoylphosphatidylcholine (DPPC). Comparisons between the calculated and experimentally measured ion currents show that the PNP approach agrees well with the measurements at low ion concentrations but overestimates the currents at higher concentrations. Concentration profiles reveal the selectivity of the peptide nanotube to cations, which is attributed to the negatively charged carbonyl oxygens inside the nanotube. The dominant cation and the minimum anion concentrations inside the cyclic peptide nanotube suggest that these cyclic peptide nanotubes can be employed as ion sensors. In the case of the polar DPPC bilayer, smaller currents are obtained in the calculation. The variation of current with polarity of the lipids implies that both polar and nonpolar lipid bilayer membranes can be utilized to regulate ion currents in the peptide nanotube and other ion channels. Strengths and limitations of the PNP theory are also discussed.