Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. However, the relationship between the vascularity of HCC and the expression of angiogenic factors has not been investigated. In addition, no detailed studies have examined the possible involvement of angiogenic factors in the grade of malignancy of HCC. The aim of this study was to determine which angiogenic factors regulate tumor angiogenesis and contribute to the invasive ability of liver tumors, especially of HCC. Northern blot analysis was used to examine the transcriptional expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and acidic FGF in resected surgical specimens (20 HCC and 9 metastatic liver tumors). Correlations between messenger RNA (mRNA) expression and arteriographic findings, as well as histopathological findings, were evaluated. Immunohistochemistry was performed to identify the localization of cells expressing VEGF in HCC. Higher levels of VEGF mRNA were observed in 12 of 20 HCC and 2 of 9 metastatic liver tumors than in corresponding nontumorous tissues. The degree of VEGF mRNA expression was significantly correlated with the intensity of tumor staining in angiograms (P<.01). On immunohistochemical observation, VEGF protein was intensely detected in HCC cells. Furthermore, basic FGF mRNA was detected in 9 of 20 HCC and was related to the capsular infiltration of cancer cells (P<.05). In contrast, no significant difference was observed in the very low levels of acidic FGF mRNA found in the tumorous and nontumorous portions of the liver. In conclusion, these results suggest that VEGF contributes to angiogenesis of liver tumors, whereas basic FGF may be involved in the invasion of HCC into the surrounding tissues.

The heterogeneous microstructure of semicrystalline polymers complicates the relationship between their electrical conductivity and carrier concentration. Charge transport models typically describe conductivity with an assumption of uniform doping throughout the material. Here, the evolution in morphology and optoelectronic properties of poly(3-hexylthiophene) (P3HT) is reported as a function of carrier concentration in an organic electrochemical transistor using a polymeric ionic liquid (PIL) as the gate insulator. Operando grazing incidence X-ray scattering reveals that negatively charged ions from the dielectric first infiltrate the amorphous regions of the semiconductor, and then penetrate the crystalline regions at a critical carrier density of 4 × 10 20 cm −3 . Upon infiltration, the crystallites expand by 12% in the alkyl stacking direction and compress by 4% in the π-π stacking direction. The change in crystal structure of P3HT correlates with a sharply increasing effective carrier mobility. UV-visible spectroscopy reveals that holes induced in P3HT first reside in the crystalline regions of the polymer, which verifies that a charge carrier need not be in the same physical domain as its associated counterion. The dopant-induced morphological changes of P3HT rationalize the dependence of mobility on carrier concentration, suggesting a phase transition of crystalline regions at high carrier concentration.

Take the stepping stones: Electrons are exchanged between both termini of α‐helical peptide self‐assembled monolayers (SAMs) on gold by a hopping mechanism with the amide groups as hopping sites (see picture). The rate constant of 0.45 s−1 for the 64‐mer peptide is significantly high for electron transfer through dielectric organic materials.

Organic metal halide Ruddlesden–Popper layered perovskite phases combine the excellent optoelectronic properties of three-dimensional, bulk hybrid perovskites with superior material stability under ambient conditions. However, the thin film structure of these layered perovskites is still poorly understood, as phase purity is typically determined solely by specular X-ray diffraction. The thin film structure of these Ruddlesden–Popper phases was examined by increasingly local characterization techniques. From the comparison of grazing-incidence wide-angle X-ray scattering patterns of cast films to expected scattering from single-crystal structures, significant in-plane disorder was observed. Spatially localized photoluminescence measurements show that films do not phase separate on the micrometer scale. Selected area electron diffraction measurements show the intergrowth of different phases within the same thin film, consistent with previous observations seen in epitaxially grown Ruddlesden–Popper complex oxides. Despite the presence of phase impurities that would typically be detrimental for device performance, fits to photothermal deflection spectroscopy measurements show relatively low Urbach energies of 33 meV for (C4H9NH3)2(CH3NH3)2Pb3I10 and 32 meV for (C4H9NH3)2(CH3NH3)3Pb4I13, indicating that the electronic properties are insensitive to the phase impurities.

Continuously enhanced photoresponsivity and suppressed dark/noise current combinatorially lead to the recent development of high-detectivity organic photodetectors with broadband sensing competence. Despite the achievements, reliable photosensing enabled by organic photodetectors (OPDs) still faces challenges. Herein, we call for heed over a universal phenomenon of detrimental sensitivity of dark current to illumination history in high-performance inverted OPDs. The phenomenon, unfavorable to the attainment of high sensitivity and consistent figures-of-merit, is shown to arise from exposure of the commonly used electron transport layer in OPDs to high-energy photons and its consequent loss of charge selectivity via systematic studies. To solve this universal problem, “double” layer tin oxide as an alternative electron transport layer is demonstrated, which not only eliminates the inconsistency between the initial and after-illumination dark current characteristics but also preserves the low magnitude of dark current, good external quantum efficiency, and rapid transient response.

Endometrial stromal differentiation (decidualization) is essential for implantation of the developing blastocyst. To investigate the process of progesterone (P)-induced decidualization of human endometrial stromal cells (ESC), a complementary DNA library enriched with P-induced genes was constructed from cultured human ESC by subtractive hybridization and the polymerase chain reaction. One of the isolated clones was the complementary DNA for the tissue inhibitor of metalloproteinase-3 (TIMP-3), a recently identified member of the human TIMP family. When human ESC were cultured in the presence of P for 6 days, the induction of TIMP-3 messenger RNA (mRNA) expression was observed by Northern blotting. In contrast, the marked induction of PRL mRNA expression and morphological changes were observed after 9 days of culture. P-induced TIMP-3 mRNA expression was dose dependent, and this induction was inhibited by the antiprogestin RU486. Estrogen did not induce TIMP-3 mRNA expression under similar conditions. In situ hybridization analysis of endometria from nonpregnant women revealed that the TIMP-3 mRNA expression was restricted to predecidualized stromal cells. At the feto-maternal interface, TIMP-3 expression was observed in fetal extravillous trophoblasts that had invaded the maternal decidual tissues as well as in the maternal decidual cells. These findings suggest that TIMP-3 is a sensitive indicator of ESC decidualization, and that the induction of TIMP-3 expression in decidual cells and trophoblasts may be important in the regulation of trophoblast invasion.

Electron transfer through α-helices has attracted much attention from the viewpoints of their contributions to efficient long-range electron transfer occurring in biological systems and their utility as molecular-electronics elements. In this study, we synthesized a long 80mer helical peptide carrying a redox-active ferrocene unit at the terminal and immobilized the helical peptide on a gold surface. The molecular length is calculated to be 134 Å, in which the helix accounts for 120 Å. The preparation conditions of the self-assembled monolayers were intentionally changed to obtain monolayers with different physical states to study the correlation between molecular motions and electron transfer. Ellipsometry and infrared spectroscopy showed that the helical peptide forms a self-assembled monolayer with vertical orientation. Electrochemical measurements revealed that an electron is transferred from the ferrocene unit to gold through the monolayer composed of this long helical peptide, and the experimental data are well explained by theoretical results calculated under the assumption that electron transfer occurs by a unique hopping mechanism with the amide groups as hopping sites. Furthermore, we have observed a unique dependence of electron transfer on the monolayer packing, suggesting the importance of structural fluctuations of peptides on the electron transfer controlled by the hopping mechanism.

Organic hole and electron transport materials are regularly employed as electron‐ and hole‐blocking layers in perovskite thin‐film solar cells. In order to optimize charge extraction in the device, these organic layers can be doped using organic small molecules. However, to date there is little work carried out on direct doping of perovskite surfaces. In this report, the change in electrical properties of thin films of MAPbI3 by surface doping the film with an organic dopant molecule: cobaltocene (Co(C5H5)2) is studied. By varying the quantity of cobaltocene deposited, the conductivity of MAPbI3 thin films is observed to be tunable over several orders of magnitude. A tunable shift in the Fermi level illustrating that charge transfer doping enables control over the interfacial energy levels, is observed. An increase in photoconductivity is seen at intermediate doping levels, indicating passivation of surface traps confirmed by increased photoluminescence. This model system provides a means to understand more complex heterointerfaces of doped organic blends at perovskite surfaces.