Turing patterns with high-resolution formed without chemical reaction in thin-film solution of organic semiconductors.

Regular patterns can form spontaneously in chemical reaction-diffusion systems under non-equilibrium conditions as proposed by Alan Turing. Here, we found that regular patterns can be generated in uphill-diffusion solution systems without a chemical reaction process through both in-situ and ex-situ observations. Organic semiconductor solution is confined between two parallel plates with controlled micron/submicron-meter distance to minimize convection of the liquid and avoid spinodal precipitation at equilibrium. The solvent evaporation concentrates the solution gradually into an oversaturated non-equilibrium condition, under which a phase-transition occurs and ordered concentration-waves are generated. By proper tuning of the experimental parameter, multiple regular patterns with micro/nano-meter scaled features (line, square-grid, zig-zag, and fence-like patterns etc.) were observed. We explain the observed phenomenon as Turing-pattern generation resulted from uphill-diffusion and solution oversaturation. The generated patterns in the solutions can be condensed onto substrates to form structured micro/nanomaterials. We have fabricated organic semiconductor devices with such patterned materials to demonstrate the potential applications. Our observation may serve as a milestone in the progress towards a fundamental understanding of pattern formation in nature, like in biosystem, and pave a new avenue in developing self-assembling techniques of micro/nano structured materials.

ALG8 Fuels Stemness Through Glycosylation of the WNT/Beta-Catenin Signaling Pathway in Colon Cancer.

Cancer stem cells (CSCs) drive tumor relapse, which is a major clinical challenge in colon cancer. Targeting CSCs presents a great opportunity in eradicating cancer cells and thus treatment of patients with cancer. However, the epigenetic control of the CSC signature and key molecules involved in colon cancer remains undefined. In this study, we demonstrated that alpha-1,3-glucosyltransferase (ALG8) is upregulated in colon cancer tissues compared with normal tissues. Overexpression of the ALG8 gene predicted poor overall survival and disease-free survival in colon cancer patients. Silencing of the ALG8 gene repressed the stemness of colon tumor cells. Xenograft mice transplanted with ALG8-deficient tumor cells significantly alleviated tumor burden and prolonged survival in comparison with control mice. Further analysis showed that ALG8 gene promoted cancer stemness through inducing glycosylation of LRP6, which activates the WNT/beta-catenin signaling pathway. Importantly, attenuation of the glycosylation using tunicamycin abrogated the effect of ALG8 gene on cancer stemness. Taken together, our findings demonstrated that ALG8 enhances colon tumorigenesis by activating the WNT/beta-catenin signaling pathway. Therefore, ALG8 gene is a potential therapeutic target in colon cancer.

Antisolvent solvothermal synthesis of MAPbBr3 nanocrystals for efficient solar photodecomposition of methyl orange.

Exploring high performance photocatalysts is of great importance to relieve the environment pollution issues. In this paper, we introduce a facile antisolvent solvothermal method to synthesize methylammonium lead tribromide perovskite (MAPbBr3) nanocrystals and successfully employ them as efficient photocatalysts. Compared to the room temperature synthesized MAPbBr3 (RT-MAPbBr3), the antisolvent solvothermal synthesized MAPbBr3 (AS-MAPbBr3) has multiple outstanding properties, such as improved crystallinity with lower grain boundary density, enhanced light absorption in visible range, suitable band gap of 2.31 eV and extended photoluminescence (PL) lifetime as long as 2627.82 ns. By taking advantages of the above merits, the AS-MAPbBr3 exhibits efficient photocatalytic performance by decomposition of methyl orange under solar light. A high apparent rate constant of 101.2 × 10-3 is achieved along with excellent cyclability, which significantly outperforms the RT-MAPbBr3 (56.0 × 10-3) and P25 (16.5 × 10-3). The underlying mechanism for MO photocatalytic degradation is deeply explored and proposed. Our present study suggests that the antisolvent solvothermal method can be a promising method to synthesize perovskite nanocrystals, and might also provide some insights in developing a series of high performance perovskite based photocatalysts.

Nitrogen vacancy induced in situ g-C3N4 p-n homojunction for boosting visible light-driven hydrogen evolution.

Graphitic carbon nitride (g-C3N4) as a novel photocatalyst with great potentials has been extensively employed in solar-driven energy conversion. Herein, the novel in situ g-C3N4 p-n homojunction photocatalyst with nitrogen vacancies (NV-g-C3N4) is successfully fabricated via hydrothermal synthesis followed by two-step calcination. The in situ NV-g-C3N4 homojunction can be employed as an effective photocatalyst for hydrogen generation through water splitting under visible light, and the optimum rate constant of 3259.1 µmol.g-1.h-1 is achieved, which is 8.7 times as high as that of pristine g-C3N4. Moreover, the markedly increased photocatalytic performance is ascribed to the enhanced light utilization, large specific surface area and unique nitrogen-vacated p-n homojunction structure, which provides more active sites and improves the separation of photo-excited electron-hole pairs. Besides, the underlying mechanism for efficient charge transportation and separation is also proposed. This work demonstrates that the remodeling of g-C3N4 p-n homojunction with nitrogen vacancies is a feasible way as highly efficient photocatalysts and might inspire some new strategies for energy and environmental applications.

Insight into charge carrier separation and solar-light utilization: rGO decorated 3D ZnO hollow microspheres for enhanced photocatalytic hydrogen evolution.

Improving efficient solar light utilization, facilitating charge transportation and reducing electron-hole recombination, are the three major challenges in photocatalysis, and numerous interests have been devoted into overcoming these issues for obtaining high performance photocatalysts. Herein, ZnO hollow microspheres/reduced graphene oxide (ZnO/rGO) composites were constructed as a high performance photocatalyst for splitting water into H2 via a one-step microwave-assisted solvothermal process. The optimized ZnO/rGO nanocomposite (the mass ratio of GO to ZnO is 1%) reached a maximum H2 evolution rate of 648.1 µmol/h/g without using noble metal as cocatalyst, which exhibiting ~2.3-fold enhancement as compared to that of the bare ZnO. This significant improvement was primarily attributed to great light-harvesting capacity and the efficient charge carrier separation and transfer. The detailed characterization of PL and EIS revealed that, in the ZnO/rGO composite, the rGO nanosheets played important roles in promoting the charge carrier separation and transfer, which therefore resulting in an enhanced activity in H2 evolution. Our present observations provide a valuable methodology for exploring novel high performance photocatalyst, especially in graphene-based inorganic hybrid systems.

Self-assembled monolayers of cyclohexyl-terminated phosphonic acids as a general dielectric surface for high-performance organic thin-film transistors.

A novel self-assembled monolayer (SAM) on AlOy /TiOx is terminated with cyclohexyl groups, an unprecedented terminal group for all kinds of SAMs. The SAM-modified AlOy /TiOx functions as a general dielectric, enabling organic thin-film transistors with a field-effect mobility higher than 5 cm(2) V(-1) s(-1) for both holes and electrons, good air stability with low operating voltage, and general applicability to solution-processed and vacuum-deposited n-type and p-type organic semiconductors.

Thymosin beta 10 correlates with lymph node metastases of papillary thyroid carcinoma.

BACKGROUND: Thymosin beta 10 (TMSB10) has recently been recognized as being an important player in the metastatic cascade including tumor angiogenesis, invasion, and metastasis. However, a role for this protein in papillary thyroid carcinoma (PTC) has not yet been established. METHODS: Real-time polymerase chain reaction was used to examine the expression of TMSB10 messenger RNA in 36 cases of thyroid tissue samples: normal thyroid, PTC without lymph node metastases (LNM) and PTC with LNM (n = 12 cases in each subgroup). For immunohistochemistry, 130 patients with PTC were selected during the period of 2004-2005, 91 with and 39 without LNM. Statistical analysis was applied to evaluate the correlation between TMSB10 expression and LNM of PTC. RESULTS: By real-time polymerase chain reaction analysis, the expression of TMSB10 messenger RNA in normal thyroid tissue, PTC without LNM, and PTC with LNM tissue were significantly different (P < 0.0001). On immunohistochemistry analysis of 130 patients with PTC, in which 91 cases had cervical LNM and 69 cases had central neck LNM, high expression levels for TMSB10 were more common in patients with cervical LNM compared with patients without (81% versus 33%, P < 0.001). Similarly, high expression levels of TMSB10 were more common in patients with central neck LNM compared with those without (87.0% versus 44.3%, P < 0.001). CONCLUSIONS: High expression levels of TMSB10 correlated with LNM in PTC, especially in the central neck region. Patients with PTC with low levels of TMSB10 expression may be unlikely to have central neck LNM and could therefore avoid prophylactic central neck dissection.

Low-voltage graphene field-effect transistors based on octadecylphosphonic acid modified solution-processed high-k dielectrics.

In this study, a solution-processed bilayer high-k dielectric (Al2O(y)/TiO(x), abbrev. as ATO) was used to realize the low-voltage operation of graphene field-effect transistors (GFETs), in which the graphene was grown by atmospheric pressure chemical vapor deposition (APCVD). Upon modifying the interface between graphene and the dielectric by octadecylphosphonic acid (ODPA), outstanding room-temperature hole mobility up to 5805 cm(2) V(-1) s(-1) and electron mobility of 3232 cm(2) V(-1) s(-1) were obtained in a small gate voltage range from -3.0 V to 3.0 V under a vacuum. Meanwhile, an excellent on/off current ratio of about 8 was achieved. Our studies demonstrate an effective route in which utilizing the low-temperature solution-processed dielectrics can achieve low-voltage and high performance GFETs.

Insights into the interfacial properties of low-voltage CuPc field-effect transistor.

The interfacial transport properties and density of states (DOS) of CuPc near the dielectric surface in an operating organic field-effect transistor (OFET) are investigated using Kelvin probe force microscopy. We find that the carrier mobility of CuPc on high-k Al2Oy/TiOx (ATO) dielectrics under a channel electrical field of 4.3 × 10(2) V/cm reaches 20 times as large as that of CuPc on SiO2. The DOS of the highest occupied molecular orbital (HOMO) of CuPc on the ATO substrate has a Gaussian width of 0.33 ± 0.02 eV, and the traps DOS in the gap of CuPc on the ATO substrate is as small as 7 × 10(17) cm(-3). A gap state near the HOMO edge is observed and assigned to the doping level of oxygen. The measured HOMO DOS of CuPc on SiO2 decreases abruptly near E(V(GS) = V(T)), and the pinning of DOS is observed, suggesting a higher trap DOS of 10(19)-10(20) cm(-3) at the interface. The relationships between DOS and the structural, chemical, as well as electrical properties at the interface are discussed. The superior performance of CuPc/ATO OFET is attributed to the low trap DOS and doping effect.

Low-voltage organic field-effect transistors (OFETs) with solution-processed metal-oxide as gate dielectric.

In this study, low-voltage copper phthalocyanine (CuPc)-based organic field-effect transistors (OFETs) are demonstrated utilizing solution-processed bilayer high-k metal-oxide (Al(2)O(y)/TiO(x)) as gate dielectric. The high-k metal-oxide bilayer is fabricated at low temperatures (< 200 °C) by a simple spin-coating technology and can be controlled as thin as 45 nm. The bilayer system exhibits a low leakage current density of less than 10(-5) A/cm(2) under bias voltage of 2 V, a very smooth surface with RMS of about 0.22 nm and an equivalent k value of 13.3. The obtained low-voltage CuPc based OFETs show high electric performance with high hole mobility of 0.06 cm(2)/(V s), threshold voltage of -0.5 V, on/off ration of 2 × 10(3) and a very small subthreshold slope of 160 mV/dec when operated at -1.5 V. Our study demonstrates a simple and robust approach that could be used to achieve low-voltage operation with solution-processed technique.

[Treatment of advanced maxillary sinus squamous carcinoma: an analysis of 92 cases].

BACKGROUND & OBJECTIVE: There is no satisfactory treatment for advanced maxillary sinus squamous carcinoma. The treatment strategy is controversial. This study aimed to explore a rational treatment for advanced maxillary sinus squamous carcinoma. METHODS: Clinical data of 92 patients with stage T3-T4 maxillary sinus squamous cell carcinoma, treated in Cancer Center of Sun Yat-sen University from Jan.1978 to Dec.2001, were reviewed. Of the 92 patients, 21 received radiotherapy alone, 8 received surgery alone, 63 received multimodality therapy (51 received surgery combined with radiotherapy, and 12 received chemoradiotherapy). RESULTS: The 3-and 5-year survival rates were significantly lower in radiotherapy group and surgery group than in multimodality therapy group (19.0% and 25.0% vs. 46.0%, P<0.05; 9.5% and 12.5% vs. 33.3%, P<0.05). In multimodality therapy group, the 3-and 5-year survival rates were 33.3% and 23.8% for the patients who received radiotherapy followed by surgery, 52.9% and 47.1% for the patients who received surgery follow by radiotherapy, 53.8% and 30.8% for the patients who received pre-and postoperative radiotherapy, and 50.0% and 33.3% for the patients who received chemoradiotherapy. There were no significant differences in survival rate between these four subgroups (P>0.05). CONCLUSIONS: The efficacy of multimodality therapy is better than that of single therapy strategy for advanced maxillary sinus squamous carcinoma. The best treatment pattern for advanced maxillary sinus squamous carcinoma needs further research.