Genome-wide identification, structural characterization and gene expression analysis of the WRKY transcription factor family in pea (Pisum sativum L.).

BACKGROUND: The WRKY gene family is one of the largest families of transcription factors in higher plants, and WRKY transcription factors play important roles in plant growth and development as well as in response to abiotic stresses; however, the WRKY gene family in pea has not been systematically reported. RESULTS: In this study, 89 pea WRKY genes were identified and named according to the random distribution of PsWRKY genes on seven chromosomes. The gene family was found to have nine pairs of tandem duplicates and 19 pairs of segment duplicates. Phylogenetic analyses of the PsWRKY and 60 Arabidopsis WRKY proteins were performed to determine their homology, and the PsWRKYs were classified into seven subfamilies. Analysis of the physicochemical properties, motif composition, and gene structure of pea WRKYs revealed significant differences in the physicochemical properties within the PsWRKY family; however, their gene structure and protein-conserved motifs were highly conserved among the subfamilies. To further investigate the evolutionary relationships of the PsWRKY family, we constructed comparative syntenic maps of pea with representative monocotyledonous and dicotyledonous plants and found that it was most recently homologous to the dicotyledonous WRKY gene families. Cis-acting element analysis of PsWRKY genes revealed that this gene family can respond to hormones, such as abscisic acid (ABA), indole-3-acetic acid (IAA), gibberellin (GA), methyl jasmonate (MeJA), and salicylic acid (SA). Further analysis of the expression of 14 PsWRKY genes from different subfamilies in different tissues and fruit developmental stages, as well as under five different hormone treatments, revealed differences in their expression patterns in the different tissues and fruit developmental stages, as well as under hormone treatments, suggesting that PsWRKY genes may have different physiological functions and respond to hormones. CONCLUSIONS: In this study, we systematically identified WRKY genes in pea for the first time and further investigated their physicochemical properties, evolution, and expression patterns, providing a theoretical basis for future studies on the functional characterization of pea WRKY genes during plant growth and development.

[Retrospective review of airway obstruction in 19 infants with pharyngeal cysts].

Objective:To discuss the clinical characteristic and treatment of laryngeal cysts in infants. Methods:The clinical data of 19 patients diagnosed with laryngeal cysts in Department of Otolaryngology, Sichuan Provincial Maternity and Child Health Care Hospital from November 2017 to April 2023 were retrospectively analyzed. Results:All of the 19 patients were diagnosed as laryngeal cysts, with clinical manifestations included respiratory distress, inspiratory dyspnea, difficulty in feeding and low and weak crying, etc. All of them were cured after surgical treatment. Conclusion:Misdiagnosis and missed diagnosis of laryngeal cysts are prone to occur in infants and young children. After diagnosis, patients should undergo early surgical treatment to remove airway obstruction and improve ventilation.

CCL2 promotes proliferation, migration and angiogenesis through the MAPK/ERK1/2/MMP9, PI3K/AKT, Wnt/ß­catenin signaling pathways in HUVECs.

Severe bone trauma can lead to poor or delayed bone healing and nonunion. Bone regeneration is based on the interaction between osteogenesis and angiogenesis. Angiogenesis serves a unique role in the repair and remodeling of bone defects. Monocyte chemoattractant protein-1, also known as CC motif ligand 2 (CCL2), is a member of the CC motif chemokine family and was the first human chemokine to be revealed to be an effective chemokine of monocytes. However, its underlying mechanism in angiogenesis of bone defect repair remains to be elucidated. Therefore, the present study investigated the detailed mechanism by which CCL2 promoted angiogenesis in bone defects based on cell and animal model experiments. In the present study, CCL2 promoted proliferation, migration and tube formation in human umbilical vein endothelial cells (HUVECs) in a concentration-dependent manner. Western blot analysis revealed that treatment of HUVECs with CCL2 upregulated the protein expression levels of rho-associated coiled-coil-containing protein kinase (Rock)1, Rock2, N-cadherin, c-Myc and VEGFR2. Furthermore, CCL2 promoted the expression of MAPK/ERK1/2/MMP9, PI3K/AKT and Wnt/ß-catenin signaling pathway-related proteins, which also demonstrated that CCL2 promoted these functions in HUVECs. Immunohistochemical staining of Sprague Dawley rat femurs following bone defects revealed that VEGF expression was positive in the newly formed bone area in each group, while the expression area of VEGF in the CCL2 addition group was markedly increased. Therefore, CCL2 is a potential therapeutic approach for bone defect repair and reconstruction through the mechanism of angiogenesis-osteogenesis coupling.

Salivary esterases dramatically reduce biostability of dentin collagen treated with galloylated polyphenols.

OBJECTIVE: To investigate the effects of salivary esterases on biostability of collagen treated by galloylated polyphenols. METHODS: Human dentin was microtomed into 6-µm-thick films, which were demineralized and treated for 60 s using solutions containing 0.6% and 2% of one of the crosslinkers: tannic acid (TAC), epigallocatechin gallate (EGCG), epigallocatechin (EGC), and N-[3-dimethylaminopropyl]-N'-ethylcarbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS), and for 1 h using EDC/NHS. Half of the treated and untreated (control) films were subjected to human saliva incubation. Collagen biostability was assessed via exogenous protease biodegradation by weight loss and hydroxyproline release, and endogenous MMPs by in situ zymography. The degradation products of galloylated polyphenols (TAC and EGCG) by saliva were monitored using proton nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). The esterase activity of saliva induced by the crosslinkers was also assessed. RESULTS: Collagen films treated with TAC and EGCG exhibited significantly improved biostability (p < 0.05); however, the enhanced biostability was severely reduced after saliva incubation (p < 0.001). For EDC/NHS treated collagen, saliva incubation showed negligible effect on the biostability. 1H NMR studies confirmed the esterase-catalyzed hydrolysis of the galloyl. GPC measurements showed decreased molecular weight of TAC in saliva indicating its chemical degradation. Both TAC and EGCG showed much higher esterase activity than other treatment groups. SIGNIFICANCE: The galloyl group plays important role in collagen crosslinking, inducing higher biostability. However, galloylated polyphenols crosslinked on collagen are highly susceptible to metabolism of human saliva by salivary esterase, dramatically compromising the enhanced biostability.

Thymol and trans-cinnamaldehyde induce apoptosis through a metacaspase-dependent mitochondrial pathway in food-spoilage yeast Zygosaccharomyces rouxii.

This work aimed for the first time to provide detailed insights into thymol and trans-cinnamaldehyde's mechanisms of action on the food-spoilage yeast Zygosaccharomyces rouxii and offers evidence in favor of the activation of an apoptosis-like phenotype. The action mechanisms of thymol and trans-cinnamaldehyde were investigated by the measurement of a series of typical apoptotic features using flow cytometer or microplate reader. Moreover, quantitative reverse transcription PCR (QRT-PCR) was performed to investigate the effects of thymol and trans-cinnamaldehyde on the transcription of key regulators of apoptosis in Z. rouxii. The results indicated that the treatment of Z. rouxii with thymol or trans-cinnamaldehyde (minimum inhibitory and subinhibitory concentrations) triggered reactive oxygen species (ROS) accumulation, elevated intracellular Ca2+ level, and depolarized mitochondrial membrane potential (MMP) coupled with hallmarks of apoptosis including mitochondrial cytochrome c (cyt c) release, metacaspase activation, phosphatidylserine (PS) exposure, and DNA fragmentation. Moreover, thymol or trans-cinnamaldehyde treatment upregulated the transcription of proapoptotic regulators including Yca1, Dnm1, Nuc1, Ndi1, and Mmi1 and downregulated the transcription of antiapoptotic regulators of Fis1 and Cdc48, further confirming the apoptosis induced by thymol and trans-cinnamaldehyde in Z. rouxii. In summary, thymol and trans-cinnamaldehyde probably induced apoptosis through a metacaspase-dependent mitochondrial pathway in Z. roxuii. These findings provide theoretical support for the development of safe and efficient agents used in food preservation. PRACTICAL APPLICATION: The results will provide a new idea for the systematic analysis of the antifungal mechanisms of thymol and trans-cinnamaldehyde and also provide a theoretical support for the development and application of natural food preservatives, which is of positive significance for the effective control of the spoilage caused by Z. rouxii in food processing and storage and the protection of consumers' health.

Feasibility study on early identification of freshness decay of fresh-cut kiwifruit during cold chain storage by Fourier transform-near infrared spectroscopy combined with chemometrics.

This work mainly aimed to evaluate the feasibility of Fourier transform-near infrared spectroscopy (FT-NIRS) combined with chemometrics in early identification of freshness decay of fresh-cut kiwifruit during simulated cold chain storage, with organoleptic evaluation as a reference. By linear discriminant analysis, the freshness decay could be identified after only 2 days of cold storage, corresponding to freshness level of 3.41 ± 0.27 N (hardness), 0.70 ± 0.05 g/kg (total acid), 8.62 ± 0.06 g/100 g (reducing sugars), 62.04 ± 1.03 mg/100 g (vitamin C) and 2.05 ± 0.11 log10 CFU/g (total plate count). Organoleptic evaluators could not perceive the freshness decay that occurred after 2 days of cold storage. Moreover, the freshness decay could be well quantitatively predicted by partial least squares regression, with low RMSEp (0.18-05.42) and high R2 (0.90-0.96). FT-NIRS appears to be a promising option for early warning of the freshness decay of fresh-cut kiwifruit during cold chain storage, thereby preventing serious spoilage and ensuring fresh fruits for consumers. PRACTICAL APPLICATION: This work is based on the fact that fresh-cut kiwifruit is prone to freshness decay under unstable cold chain conditions, using FT-NIRS combined with chemometrics to identify the freshness decay early and rapidly, to a certain extent, early warn freshness decay and effectively prevent serious spoilage. The technology can be used for food regulatory agencies to monitor the freshness of fresh-cut kiwifruit, and can also be applied for fruit processing enterprises and dealers to ensure the freshness and high quality of fresh-cut kiwifruit.

Baicalin induces apoptosis and autophagy in human osteosarcoma cells by increasing ROS to inhibit PI3K/Akt/mTOR, ERK1/2 and ß-catenin signaling pathways.

Baicalin, a flavonoid derivative, exerts antitumor activity in a variety of neoplasms. However, whether baicalin exerts antitumor effects on osteosarcoma cells remains to be elucidated. In this study, treatment with baicalin reduced the proliferation and invasive potential of osteosarcoma cells and reduced the mitochondrial membrane potential, which eventually caused mitochondrial apoptosis. In addition, baicalin increased intercellular Ca2+ and ROS concentrations. Baicalin-induced apoptosis was confirmed by enhanced Bax, cleaved caspase-3, and cleaved PARP levels and decreased Bcl-2 levels. The increase in LC3-II and p62 suggested that baicalin induced autophagosome formation but ultimately inhibited downstream autophagy. Moreover, apoptosis induced by baicalin was attenuated by the addition of 3-MA. Furthermore, we found that baicalin inhibited the PI3K/Akt/mTOR, ERK1/2 and ß-catenin signaling pathways. Chelation of free Ca2+ by BAPTA-AM also inhibited both apoptosis induction and ROS concentration changes. Finally, NAC pretreatment reversed baicalin treatment outcomes, including the increase in Ca2+ concentration, induction of apoptosis and autophagy, and inhibition of the pathways. Molecular docking results indicated that baicalin might interact with the structural domain of PI3Kγ. Thus, baicalin may be considered a potential candidate for osteosarcoma treatment.

Antifungal activities and mechanisms of trans-cinnamaldehyde and thymol against food-spoilage yeast Zygosaccharomyces rouxii.

Due to hydrophobicity, plant essential oil components trans-cinnamaldehyde and thymol exert broad-spectrum antimicrobial activities by interfering with the structures and functions of microbial cell membranes, yet their antifungal properties against food-spoilage yeast Zygosaccharomyces rouxii are still unclear. This work aimed to elucidate their antifungal activities and mechanisms against Z. rouxii. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were measured using broth dilution method to evaluate the antifungal activities. Membrane permeability, potential and integrity, intracellular ATP content, and intracellular pH (pHin ) were determined, and membrane damage was observed by scanning electron microscope (SEM) to investigate the antifungal mechanisms. The MICs of trans-cinnamaldehyde and thymol were 0.3125 and 0.0625 mg/ml, respectively, and the MFCs were 1.25 and 0.125 mg/ml, respectively. Increased membrane permeability, membrane hyperpolarization, decreased membrane integrity, reduced intracellular ATP content, and lowered pHin were found after trans-cinnamaldehyde or thymol treatment at the MIC and MFC levels, and thymol exhibited more severe influence on cell membrane. SEM observation further confirmed that trans-cinnamaldehyde caused cell membrane shrinkage and invagination, while thymol resulted in perforation in cell membrane. These results suggest that trans-cinnamaldehyde and thymol exert anti-Z. rouxii activities by inducing cell membrane damage and subsequent intracellular homeostasis disruption. Cellular contents leakage and intracellular homeostasis disruption probably proceed more rapidly after thymol inducing perforation in the cell surface, thereby thymol exerting better anti-Z. rouxii activity. PRACTICAL APPLICATION: The addition of a small amount of thymol (0.125 mg/ml) is sufficient to effectively inhibit the growth of Z. rouxii in apple juice concentrate. Based on our previous work, the addition of thymol (0.125 mg/ml) in apple juice concentrate did not significantly affect the organoleptic property of the diluted apple juice (5°Brix) used for producing commercial apple juice products. Therefore, thymol is practical for application at the effective concentration (0.125 mg/ml) in apple juice concentrate.

Methacrylate-functionalized proanthocyanidins as novel polymerizable collagen cross-linkers - Part 1: Efficacy in dentin collagen bio-stabilization and cross-linking.

OBJECTIVE: The aim of the study was to investigate the effects of methacrylate-functionalized proanthocyanidins (MAPAs) on dentin collagen's bio-stabilization against enzymatic degradation and crosslinking capability. METHODS: Three MAPAs were synthesized via varying methacrylate (MA) to proanthocyanidins (PA) feeding ratios of 1:2, 1:1, and 2:1 to obtain MAPA-1, MAPA-2, and MAPA-3, respectively. The three MAPAs were structurally characterized by proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FTIR) spectroscopic methods. 5-µm-thick dentin films were microtomed from dentin slabs of third molars. Following demineralization, films or slabs were treated with 1% MAPAs or PA in ethanol for 30 s. Collagen bio-stabilization against enzymatic degradation was analyzed by weight loss (WL) and hydroxyproline release (HYP) of films, as well as scanning electron microscopy (SEM) on dentin slabs. Crosslinking capacity and interactions of MAPAs with collagen were investigated by FTIR. Data were analyzed by ANOVA and Tukey's test (α = 0.05%). RESULTS: MA:PA feeding ratios affected MAPAs' chemical structures which in turn led to different collagen stabilization efficacy against degradation and varied collagen crosslinking capabilities. Higher collagen stabilization efficacy was detected using MAPA-1 (WL 10.52%; HYP 13.53 µg/mg) and MAPA-2 (WL 5.99%; HYP 11.02 µg/mg), which was comparable to that using PA (WL 8.79%; HYP 13.17 µg/mg) (p > 0.05), while a lower collagen stability occurred in MAPA-3 (WL 38.48%; HYP 29.49 µg/mg), indicating excessive MA-functionalization would compromise its stabilization efficacy. In comparison, complete digestion was detected for untreated collagen (WL 100%; HYP 102.76 µg/mg). The above results were consistent with collagen crosslinking efficacy of the three MAPAs revealed by SEM and FTIR. SIGNIFICANCE: A new class of novel polymerizable collagen cross-linkers MAPAs was synthesized and shown that, when appropriate MA:PA ratios were applied, the resulting MAPAs could render high collagen stability and the ability to copolymerize with resin monomers, overcoming the drawbacks of PA. These new polymerizable crosslinkers, when included in adhesives, could lead to long-lasting dentin bonding.

Methacrylate-functionalized proanthocyanidins as novel polymerizable collagen cross-linkers - Part 2: Effects on polymerization, microhardness and leaching of adhesives.

OBJECTIVE: The aim of the study was to investigate the effects of a novel polymerizable collagen cross-linker methacrylate-functionalized proanthocyanidins (MAPA) on the polymerization, microhardness and leaching of a HEMA-based experimental dental adhesive system. METHODS: Three MAPAs were synthesized using different methacrylate (MA) to proanthocyanidins (PA) feeding ratios of 1:2, 1:1, and 2:1 to obtain MAPA-1, MAPA-2, and MAPA-3, respectively. The resulting three MAPAs and PA were added to an experimental adhesive formulated with HEMA and a tri-component photoinitiator system (0.5 wt% CQ/EDMAB/DPIHP) at 1%, 5% and 10% MAPA or PA concentrations (wt%). The adhesive polymerization kinetics was measured continuously in real-time for 10 min using a Fourier-transform infrared spectroscopy (FTIR) with an attenuated total reflectance (ATR) accessory. Degree of conversion (DC) and Vickers microhardness (MH) of cured adhesives were measured at 72 h post-cure. The leaching of cured adhesives in DI water was monitored using UV-vis spectrophotometer. Statistical analysis was performed using one-way and two-way ANOVA, Tukey's (p < 0.05). RESULTS: The adhesive formulations with 1%, 5% and 10% MAPAs-1, -2, -3 all generated higher rate of polymerization and 10-min DC than the formulations with PA at the same concentrations. At 72 h post-cure, the adhesive formulation with 5% MAPA-2 exhibited significantly higher DC (99.40%) and more than doubled MH (18.93) values than the formulation with 5% PA (DC = 89.47%, MH = 8.41) and the control (DC = 95.46%, MH = 9.33). Moreover, the cured adhesive with 5% MAPA-2 demonstrated significantly reduced PA leaching in comparison with cured adhesive with 5% PA. SIGNIFICANCE: Synthesized MAPA is a novel class of polymerizable collagen cross-linker that not only stabilizes dentin collagen via its PA component, but also improves polymerization, mechanical properties and stability of HEMA-based adhesives via its MA component. By inheriting the benefit while overcoming the drawback of PA, MAPA offers a revolutionary solution for improved bond-strength and longevity of dental restorations.

[Construction of green space ecological network in Dongting Lake region with comprehensive evaluation method]. / 基于综合评价法的洞庭湖区绿地生态网络构建.

Green space ecological network is important for improving the fragmentation of regional ecological space, biodiversity loss, imbalance of supply and demand in ecosystem services, and ensuring regional ecology. With Dongting Lake region as an example, the ecological sources were evaluated and identified, and basic ecological resistance of grid element was calculated from the perspectives of comprehensive ecosystem service function evaluation, potential biodiversity comprehensive index evaluation and morphological spatial pattern analysis with the support of 3S technology. We corrected the basic ecological resistance by night light index, used the minimum cumulative resistance model to identify ecological corridors, and constructed a weighted evaluation model, eva-luated the degree of aggregation and dispersion of the sources, as well as the contribution of ecological connection of the corridors. Furthermore, we compared and evaluated the structural characteristic index of the integrated networks, the potential "source sink" networks and the planning networks. The results showed that the spatial distribution of the sources was uneven, with forest land, shrubland and wetland acounting for 95.9% of the total area. The Dongting Lake wetland located in the middle of the region was at high ecological risk. The closer the source was to the center of the ecological network system and the smaller the average minimum cumulative resistance was to other sources, the stronger the advantages of aggregation and dispersion. The denser the distribution of medium and high ecological quality sources was around the high ecological quality sources, the higher the aggregation and dispersion. The closer the corridor was to the high ecological quality sources, the greater contribution of ecological connection. Forest land, shrubland, especially river played an important role in connecting natural ecosystem and human social system. The "source-sink" planning greenways formed a supplement to the "source-sink" potential ecological corridors. Compared with the "source-sink" potential network, the α, ß, γ and ρ index of the integrated network was increased by 123.1%, 25.8%, 26.2% and 74.6% respectively. Compared with the "source-sink" planning network, the α, ß, γ and ρ index was increased by 190.0%, 31.1%, 32.5% and 114.6% respectively. The results could provide reference for the construction of green space ecological network and planning of land use in Dongting Lake region.

Elucidation of molecular pathways responsible for the accelerated wound healing induced by a novel fibrous chitin dressing.

Fibrous chitin dressing (FCD) prepared from a NaOH-urea aqueous solution of chitin via a physical process was used to study its effect on wound healing using a full-thickness cutaneous wound model in rats and mice. It was demonstrated that wounds in rats covered with the FCD showed faster collagen (especially type I collagen) growth and speedier healing than those with Gauze (12 days versus 16 days). The ability of FCD to promote wound healing was also observed on wild-type (WT) mice. For MyD88-knockout mice, however, FCD displayed no beneficial but an adverse effect on wound healing: the healing time for wounds treated with FCD was even longer than those treated with gauze. Importantly, in vivo studies indicated that FCD-treated mice, compared to gauze-treated ones, exhibited markedly higher expressions of MyD88, IKBα, TGF-ß, P-TßR II, TßR II and P-Smad2/3 in wild-type mice. For MyD88 knockout mice, however, the expressions of those molecules were inhibited and lowered in FCD-treated ones than those treated with gauze. In vitro studies confirmed that chitin increased the expression of TGF-ß, P-TßRII and P-Smad2/3 while the expressions of those molecules were significantly inhibited with CD14 antibody (p < 0.05). These results indicated that FCD accelerated wound healing through a MyD88-dependent pathway, followed by a TGF-ß/Smad pathway. This work not only demonstrated the superior wound healing effect of chitin-derived dressing, but also provided for the first time the underlying molecular mechanism, further establishing chitin as an important biomedical material for potential clinical applications.

[Analysis the statue of growth and development of infants and young children aged 6- 23 months in poor rural areas of Hunan Province, China].

OBJECTIVE: To describe the statue of growth and development among infants and young children aged 6-23 months in poor rural areas of Hunan Province. METHODS: A total of 15 248 rural infants and young children aged 6-23 months in 54 poor counties of Wuling Mountains and Luoxiao Mountains in Hunan Province were selected by Probability-Proportional-to-Size Sampling( PPS) between 2009 and 2015. Participants' length and weight were tested, WHZ, WAZ, HAZ and BMI Z score were calculated according to The WHO Child Growth Standards, and describe the rate of wasting, underweight, stunting and low BMI, and the physical growth level of children were evaluated according to the WHO standards. RESULTS: The average weight of girls aged 6-23 months in poor rural areas of Hunan Province were 9. 17 kg, lower than boys which were 9. 79 kg. The average length of girls aged 6-23 months were 75. 53 cm, lower than boys which were 77. 19 cm. The average BMI of girls aged 6-23 months were15. 96, lower than boys which were 16. 40( P < 0. 05). The curve of weight-for-length Z scores and weight-for-age Z scores and length-for-age Z scores of infants and young children aged 6-23 months were lower than the WHO standards( P < 0. 05). The rate of wasting, underweight, stunting and low BMI of infants and young children aged 6-23 months were 3. 9%, 5. 1%, 7. 2% and 3. 9%, and boys were higher than girls in the rate of underweight and stunting, the rate of underweight and stunting were increased with the growth of age( P < 0. 05). CONCLUSION: The problem of growth and development of infants and young children aged 6-23 months in poor rural areas of Hunan Province are serious, and there are lower than the WHO standards. To improve the nutrition and health of infants and young children in poor rural areas, the ability of child health care and the feeding knowledge of caregivers are need to be improved.

Conjugated foldamers with unusually high space-charge-limited current hole mobilities.

Charge carrier mobility and its optimization play a critical role in the development of cutting-edge organic electronic and optoelectronic devices. Even though space-charge-limited current (SCLC) hole mobilities as high as 1.4 cm(2) V(-1) s(-1) have been reported for microscopically sized highly ordered liquid-crystalline conjugated small molecules, the SCLC hole mobility of device-sized thin films of conjugated polymers is still much lower, ranging from 10(-6) to 10(-3) cm(2) V(-1) s(-1). Herein, we report the synthesis, characterizations, and thin-film SCLC mobility of three discotic conjugated polymers, INDT-TT, INDT-BT, and INDT-NDT. Optical studies indicate that polymer INDT-NDT adopts a folded conformation in solutions of good or poor solvents, whereas polymer INDT-TT stays as random monomeric chains in good solvents and interchain aggregates in poor solvents. INDT-BT polymer chains, however, stay as foldamers in dilute solutions of good solvents but interchain aggregates in concentrated solutions or poor solvents. Circular dichroism spectroscopy provides clear evidence for the helical folding of INDT-NDT in solutions. Thin films spin-coated from 1,2-dichlorobenzene solutions of the polymers show SCLC hole mobility of 2.20 × 10(-6), 8.79 × 10(-5), and 2.77 × 10(-2) cm(2) V(-1) s(-1) for INDT-TT, INDT-BT, and INDT-NDT, respectively. HRTEM and powder XRD measurements show that INDT-NDT pristine thin films contain nanocrystalline domains, whereas the INDT-TT and INDT-BT films are amorphous. Thin films of INDT-NDT:PC71BM blends show increased crystallinity and further improved SCLC hole mobility up to 1.29 × 10(-1) cm(2) V(-1) s(-1), one of the highest SCLC mobility values ever recorded on solution-processed organic semiconducting thin films. The persistent folding conformation of INDT-NDT is believed to be responsible for the high crystallinity of its thin films and its high SCLC mobilities.

A novel rapamycin-polymer conjugate based on a new poly(ethylene glycol) multiblock copolymer.

PURPOSE: Rapamycin has demonstrated potent anti-tumor activity in preclinical and clinical studies. However, the clinical development of its formulations was hampered due to its poor solubility and undesirable distribution in vivo. Chemical modification of rapamycin presents an opportunity for overcoming the obstacles and improving its therapeutic index. The objective of this study is to develop a drug-polymer conjugate to increase the solubility and cellular uptake of rapamycin. METHODS: We developed the rapamycin-polymer conjugate using a novel, linear, poly(ethylene glycol) (PEG) based multiblock copolymer. Cytotoxicity and cellular uptake of the rapamycin-polymer conjugate were evaluated in various cancer cells. RESULTS: The rapamycin-polymer conjugate provides enhanced solubility in water compared with free rapamycin and shows profound activity against a panel of human cancer cell lines. The rapamycin-polymer conjugate also presents high drug loading capacity (wt% ~ 26%) when GlyGlyGly is used as a linker. Cellular uptake of the conjugate was confirmed by confocal microscopic examination of PC-3 cells that were cultured in the presence of FITC-labled polymer (FITC-polymer). CONCLUSION: This study suggests that the rapamycin-polymer conjugate is a novel anti-cancer agent that may provide an attractive strategy for treatment of a wide variety of tumors.

Morphology control of nanofibril donor-acceptor heterojunction to achieve high photoconductivity: exploration of new molecular design rule.

Donor-acceptor nanofibril composites have been fabricated, and the dependence of their photocurrent response on the structure and morphology of the donor part has been systematically investigated. The nanofibril composites were composed of template nanofibers, assembled from an electron acceptor molecule, perylene tetracarboxylic diimide (PTCDI), onto which (through drop-casting) various electron donor molecules (D1-D4) were coated. The donor molecules have the same π-conjugated core, but different side groups. Due to the different side groups, the four donor molecules showed distinctly different propensity for intermolecular aggregation, with D1-D3 forming segregated phases, while D4 prefers homogeneous molecular distribution within the film. It was found that the nanofibril composites with D4 exhibit the highest photocurrent, whereas those with aggregation-prone D1-D3 exhibited much lower photocurrent under the same illumination condition. Solvent annealing is found to further enhance the aggregation of D1-D3 but facilitate more uniform molecular distribution of D4 molecules. As a result, the photocurrent response of PTCDI fibers coated with D1-D3 decreased after vapor annealing, whereas those coated with D4 further increased. The detrimental effect of the aggregation of donor molecules on the PTCDI fiber is likely due to the enhanced local electrical field built up by the high charge density around the aggregate-nanofiber interface, which hinders the charge separation of the photogenerated electron-hole pair. The results reported in this study give further insight into the molecular structural effect on photoconductivity of hybrid materials, particularly those based on donor-acceptor composites or interfaces, and provide new molecular design rules and material processing guidelines to achieve high photoconductivity.

Synthesis and optical properties of triphenylene-based dendritic donor perylene diimide acceptor systems.

A donor-acceptor charge transfer system based on two discotic mesogens has been synthesized. The donor is either a triphenylene (POG0) or a triphenylene-based conjugated dendron (POG1), while the acceptor is a perylene diimide (PDI) core. The donors are covalently linked to the bay positions of the PDI core through an ether linkage. In chloroform, due to the short donor-acceptor distance and the matching frontier orbital levels, photoinduced charge transfer from either the donor excitation or the acceptor excitation are both thermodynamically and kinetically favored, resulting in efficient quenching of both donor and acceptor fluorescence. In a less polar solvent, hexane, while charge transfer is still the dominant mechanism for decay of the excited electronic state of POG1, photoinduced charge transfer is no longer energetically favorable for POG0 when the acceptor PDI core is excited, making the PDI core of POG0 weakly fluorescent in chloroform but strongly so in hexane. In solid film, POG0 is highly aggregated through both PDI-PDI and triphenylene-triphenylene homotopic stacking. POG1, on the other hand, aggregates through triphenylene dendrons with limited PDI-PDI core stacking, presumably due to the steric hindrance caused by bulky triphenylene moieties which block the access to the PDI core. The efficient photoinduced charge transfer, coupled with the homotopic stacking that forms separated electron-transporting PDI-stacked columns and hole transporting triphenylene-stacked columns, suggests that the reported donor-acceptor systems based on dual-discotic mesogens are potentially new efficient photovoltaic materials.

Synthesis and structural analysis of a novel iodinated cyclopentadienone via ring-contraction iodination and its application in synthesis of alkyne-functionalized cyclopentadienones.

The first iodinated cyclopentadienone was isolated and its structure was confirmed by single crystal X-ray analysis. Based on this intermediate, the first direct C-C bond formation on cyclopentadienone ring was achieved. The photo induced intramolecular charge transfer of alkynylated cyclopentadienones was evaluated by solvent polarity effect on their electronic absorption spectra.