Heterogeneous Fenton water purification catalyzed by iron phosphide (FeP)

Heterogeneous Fenton reaction has a great application potential in water purification, but efficient catalysts are still lacking. Iron phosphide (FeP) has a higher activity than the conventional Fe-based catalysts for Fenton reactions, but its ability as a Fenton catalyst to directly activate H₂O₂ remains unreported. Herein, we demonstrate that the fabricated FeP has a lower electron transfer resistance than the typical conventional Fe-based catalysts, i.e., Fe₂O₃, Fe₃O₄, and FeOOH, and thus could active H₂O₂ to produce hydroxyl radicals more efficiently. In the heterogeneous Fenton reactions for sodium benzoate degradation, the FeP catalyst presents a superior activity with a reaction rate constant more than 20 times those of the other catalysts (i.e., Fe₂O₃, Fe₃O₄, and FeOOH). Moreover, it also exhibits a great catalytic activity in the treatment of real water samples and has a good stability in the cycling tests. Furthermore, the FeP could be loaded onto a centimeter-sized porous carbon support and the prepared macro-sized catalyst exhibits an excellent water treatment performance and can be well recycled. This work reveals a great potential of FeP as a catalyst for heterogeneous Fenton reactions and may inspire further development and practical application of highly efficient catalysts for water purification.

Distinguishing homogeneous advanced oxidation processes in bulk water from heterogeneous surface reactions in organic oxidation

Clarifying the reaction pathways at the solid-water interface and in bulk water solution is of great significance for the design of heterogeneous catalysts for selective oxidation of organic pollutants. However, achieving this goal is daunting because of the intricate interfacial reactions at the catalyst surface. Herein, we unravel the origin of the organic oxidation reactions with metal oxide catalysts, revealing that the radical-based advanced oxidation processes (AOPs) prevail in bulk water but not on the solid catalyst surfaces. We show that such differing reaction pathways widely exist in various chemical oxidation (e.g., high-valent Mn³⁺ and MnO_X) and Fenton and Fenton-like catalytic oxidation (e.g., Fe²⁺ and FeOCl catalyzing H₂O₂, Co²⁺ and Co₃O₄ catalyzing persulfate) systems. Compared with the radical-based degradation and polymerization pathways of one-electron indirect AOP in homogeneous reactions, the heterogeneous catalysts provide unique surface properties to trigger surface-dependent coupling and polymerization pathways of a two-electron direct oxidative transfer process. These findings provide a fundamental understanding of catalytic organic oxidation processes at the solid-water interface, which could guide the design of heterogeneous nanocatalysts.

Simultaneous nanocatalytic surface activation of pollutants and oxidants for highly efficient water decontamination

Removal of organic micropollutants from water through advanced oxidation processes (AOPs) is hampered by the excessive input of energy and/or chemicals as well as the large amounts of residuals resulting from incomplete mineralization. Herein, we report a new water purification paradigm, the direct oxidative transfer process (DOTP), which enables complete, highly efficient decontamination at very low dosage of oxidants. DOTP differs fundamentally from AOPs and adsorption in its pollutant removal behavior and mechanisms. In DOTP, the nanocatalyst can interact with persulfate to activate the pollutants by lowering their reductive potential energy, which triggers a non-decomposing oxidative transfer of pollutants from the bulk solution to the nanocatalyst surface. By leveraging the activation, stabilization, and accumulation functions of the heterogeneous catalyst, the DOTP can occur spontaneously on the nanocatalyst surface to enable complete removal of pollutants. The process is found to occur for diverse pollutants, oxidants, and nanocatalysts, including various low-cost catalysts. Significantly, DOTP requires no external energy input, has low oxidant consumption, produces no residual byproducts, and performs robustly in real environmental matrices. These favorable features render DOTP an extremely promising nanotechnology platform for water purification.

Removal of organic micropollutants from water through advanced oxidation processes is hampered by the excessive input of energy and/or chemicals as well as the large amounts of residuals resulting from incomplete mineralization. Here the authors present a new alternative water purification technology to adsorption and advanced oxidation.

Quantitative Coassembly for Precise Synthesis of Mesoporous Nanospheres with Pore Structure-Dependent Catalytic Performance

Precise synthesis of porous materials is essential for their applications. Self-assembly is a widely used strategy for synthesizing porous materials, but quantitative control of the assembly process still remains a great challenge. Here, a quantitative coassembly approach is developed for synthesizing resin/silica composite and its derived porous spheres. The assembly behaviors of the carbon and silica precursors are regulated without surfactants and the growth kinetics of the composite spheres are quantitatively controlled. This assembly approach enables the precise control of the size and pore structures of the derived carbon spheres. These carbon spheres provide a good platform to explore the structure-performance relationships of porous materials, and demonstrate their pore structure-dependent performance in catalytic water decontamination. This work provides a simple and robust approach for precise synthesis of porous spheres and brings insights into function-oriented design of porous materials.

Interface-Promoted Direct Oxidation of p-Arsanilic Acid and Removal of Total Arsenic by the Coupling of Peroxymonosulfate and Mn-Fe-Mixed Oxide

As one of the extensively used feed additives in livestock and poultry breeding, p-arsanilic acid (p-ASA) has become an organoarsenic pollutant with great concern. For the efficient removal of p-ASA from water, the combination of chemical oxidation and adsorption is recognized as a promising process. Herein, hollow/porous Mn-Fe-mixed oxide (MnFeO) nanocubes were synthesized and used in coupling with peroxymonosulfate (PMS) to oxidize p-ASA and remove the total arsenic (As). Under acidic conditions, both p-ASA and total As could be completely removed in the PMS/MnFeO process and the overall performance was substantially better than that of the Mn/Fe monometallic system. More importantly, an interface-promoted direct oxidation mechanism was found in the p-ASA-involved PMS/MnFeO system. Rather than activate PMS to generate reactive oxygen species (i.e., SO₄^·-, ·OH, and ¹O₂), the MnFeO nanocubes first adsorbed p-ASA to form a ligand-oxide interface, which improved the oxidation of the adsorbed p-ASA by PMS and ultimately enhanced the removal of the total As. Such a direct oxidation process achieved selective oxidation of p-ASA and avoidance of severe interference from the commonly present constituents in real water samples. After facile elution with dilute alkali solution, the used MnFeO nanocubes exhibited superior recyclability in the repeated p-ASA removal experiments. Therefore, this work provides a promising approach for efficient abatement of phenylarsenical-caused water pollution based on the PMS/MnFeO oxidation process.

Catalytic degradation of ciprofloxacin by a visible-light-assisted peroxymonosulfate activation system: Performance and mechanism

Peroxymonosulfate (PMS) is extensively used as an oxidant to develop the sulfate radical-based advanced oxidation processes in the decontamination of organic pollutants and various PMS activation methods have been explored. Visible-light-assisted PMS activation to construct a Fenton-like process has shown a great potential for pollution control. In our work, BiVO₄ nanosheets were prepared using a hydrothermal process and used to activate PMS under visible light. A rapid degradation of ciprofloxacin (CIP) was achieved by dosing PMS (0.96 g/L), BiVO₄ (0.32 g/L) under visible light with a reaction rate constant of 77.72-fold higher than that in the BiVO₄/visible light process. The electron spin resonance and free radical quenching experiments indicate that reactive species of ^•O₂^-, h⁺, •OH and SO₄^•- all worked, where h⁺, •OH and SO₄^•- were found as the dominant contributors to the CIP degradation. The spectroscopic analyses further demonstrate that the photoinduced electrons were directly involved in the PMS activation process. The generated ^•O₂^- was partially utilized to activate PMS and more •OH was produced because of the chain reactions between SO₄^•- and H₂O/OH^-. In this process, PMS acted as an electron acceptor to transfer the photo-induced charges from the conduction band of BiVO₄ and PMS was successfully activated to yield the high-powered oxidative species. From the degradation intermediates of CIP detected by a liquid-chromatography-mass spectrometer, the possible degradation pathways were proposed. The substantially decreased toxicity of CIP after the reaction was also observed. This work might provide new insights into the visible-light-assisted PMS activation mechanisms and is useful to construct environmentally-friendly catalytic processes for the efficient degradation of organic pollutants.

Degradation of benzoic acid in an advanced oxidation process: The effects of reducing agents

Fenton reaction is widely used for hazardous pollutant degradation. Reducing agents (RAs) have been proven to be efficient in promoting the generation of HO• in Fenton reaction by accelerating the redox cycle of Fe³⁺/Fe²⁺. However, the roles of different RAs in Fenton reaction remain unrevealed. In this work, the catalytic activity of three RAs, i.e., hydroxylamine (NH₂OH), ascorbic acid (AA) and cysteine (Cys), on the degradation of benzoic acid (BA) and the hydroxyl radical formation in the Fenton-RAs system were investigated. Results show the catalytic performance of RAs in BA degradation by Fenton reaction followed an order of NH₂OH > AA > Cys. Compared with the conventional Fenton system, the effective pH range in the Fenton-NH₂OH system extended from 3.0 to 5.0, while the optimal pH in the Fenton-AA and Fenton-Cys systems ranged from 3.0 to 4.0. The Fenton-AA system exhibited a two-stage reaction toward BA degradation, which was different from the Fenton-NH₂OH and Fenton-Cys systems. Furthermore, the dosing manner of AA was found to be a key factor governing its role in the Fenton-AA system. This observation suggests the different mechanisms behind the enhancement of the three RAs in Fenton system. Different from NH₂OH and Cys, AA would inhibit the generation of HO•, especially at the fast stage of degradation process, where Fe³⁺ has not accumulated yet. In addition, the economic analysis using the electrical energy per order indicates Fenton-NH₂OH system was economically feasible with the lowest energy input, compared to Fenton-AA and Fenton-Cys systems. These results are useful to better understand the roles of RAs in Fenton system, and also provide guidance about the selection and dosing manner of suitable RAs in the advanced oxidation processes.

Carbon-Based Catalyst Synthesized and Immobilized under Calcium Salt Assistance To Boost Singlet Oxygen Evolution for Pollutant Degradation

Carbon-based materials are recognized as promising candidates for pollutant degradation because of their environmental benignity. Massive and cost-effective production and efficient recovery of carbon-based catalysts are crucial to apply this technology. However, various nanostructured carbons with different dimensions are usually utilized as precursors while not considering their complex preparation procedures and the high costs of ingredients. Moreover, catalyst separation and recovery are not given sufficient attention. In this work, a calcium salt-assisted pyrolysis strategy is proposed to tune the catalytic site formation of carbon-based catalysts. Results show that blending equal amounts of Ca²⁺ (calcium chloride) and organic precursors could greatly improve the catalytic activity of the carbonated product to activate peroxymonosulfate for pollutant degradation. In addition, the proposed synthetic strategy is universal to most of the readily accessed and cost-effective organic precursors. Singlet oxygen is identified as the main reactive oxidant for pollutant removal in the catalytic reaction. By cross-linking calcium ions and alginate as a hydrogel to immobilize the catalyst, the carbon material could be readily recovered. Furthermore, a long-term continuous-flow reactor test is conducted to validate the effectiveness of applying the immobilized catalyst to treat a synthetic wastewater with 0.5 mM bisphenol A. As a result, a green synthesis and immobilization strategy for persulfate catalysts is successfully established, and the prepared catalyst might be applied for wastewater treatment through using calcium salt in two purposes.

Investigation and comparison of the anti-tumor activities of lactoferrin, α-lactalbumin, and β-lactoglobulin in A549, HT29, HepG2, and MDA231-LM2 tumor models

To investigate the anti-tumor activities of lactoferrin, α-lactalbumin, and β-lactoglobulin, 4 types of human tumor cells (lung tumor cell A549, intestinal epithelial tumor cell HT29, hepatocellular cell HepG2, and breast cancer cell MDA231-LM2) were exposed to 3 proteins, respectively. The effects on cell proliferation, migration, and apoptosis were detected in vitro, and nude mice bearing tumors were administered the 3 proteins in vivo. Results showed that the 3 proteins (20 g/L) inhibited viability and migration, as well as induced apoptosis, in 4 tumor cells to different degrees (compared with the control). In vivo, tumor weights in the HT29 group (0.84 ± 0.22 g vs. control 2.05 ± 0.49 g) and MDA231-LM2 group (1.11 ± 0.25 g vs. control 2.49 ± 0.57 g) were significantly reduced by lactoferrin; tumor weights in the A549 group (1.07 ± 0.19 g vs. control 3.11 ± 0.73 g) and HepG2 group (2.32 ± 0.46 g vs. control 3.50 ± 0.74 g) were significantly reduced by α-lactalbumin. Moreover, the roles of lactoferrin, α-lactalbumin, and β-lactoglobulin in regulating apoptotic proteins were validated. In summary, lactoferrin, α-lactalbumin, and β-lactoglobulin were proven to inhibit growth and development of A549, HT29, HepG2, and MDA231-LM2 tumors to different degrees via induction of cell apoptosis.

Ultrasensitive Fluorescence Detection of Peroxymonosulfate Based on a Sulfate Radical-Mediated Aromatic Hydroxylation

Recently, peroxymonosulfate (PMS)-based advanced oxidation processes have exhibited broad application prospects in the environment field. Accordingly, a simple, rapid, and ultrasensitive method is highly desired for the specific recognition and accurate quantification of PMS in various aqueous solutions. In this work, SO₄^•--induced aromatic hydroxylation was explored, and based on that, for the first time, a novel fluorescence method was developed for the PMS determination using Co²⁺ as a PMS activator and benzoic acid (BA) as a chemical probe. Through a suite of spectral, chromatographic, and mass spectrometric analyses, SO₄^•- was proven to be the dominant radical species, and salicylic acid was identified as the fluorescent molecule. As a result, a whole radical chain reaction mechanism for the generation of salicylic acid in the BA/PMS/Co²⁺ system was proposed. This fluorescence method possessed a rapid reaction equilibrium (<1 min), an ultrahigh sensitivity (detection limit = 10 nM; quantification limit = 33 nM), an excellent specificity, and a wide detection range (0-100 μM). Moreover, it performed well in the presence of possible interfering substances, including two other peroxides (i.e., peroxydisulfate and hydrogen peroxide), some common ions, and organics. The detection results for real water samples further validated the practical utility of the developed fluorescence method. This work provides a new method for the specific recognition and sensitive determination of PMS in complex aqueous solutions.

Recovery of Lost Color and Depth Frames in Multiview Videos

In this paper, we consider an integrated error concealment system for lost color frames and lost depth frames in multiview videos with depths. We first proposed a pixel-based color error-concealment method with the use of depth information. Instead of assuming that the same moving object in consecutive frames has minimal depth difference, as is done in a state-of-the-art method, a more realistic situation in which the same moving object in consecutive frames can be in different depths is considered. In the derived motion vector candidate set, we consider all the candidate motion vectors in the set, and weight the reference pixels by the depth differences to obtain the final recovered pixel. Compared with the two state-of-the-art methods, the proposed method has average peak signal-to-noise ratio gains of up to 8.73 and 3.98 dB, respectively. Second, we proposed an iterative depth frame error-concealment method. The initial recovered depth frame is obtained by depth-image-based rendering from another available view. The holes in the recovered depth frame are then filled in the proposed priority order. Preprocessing methods (depth difference compensation and inconsistent pixel removal) are performed to improve the performance. Compared with a method that uses the available motion vector in a color frame to recover the lost depth pixels, the hybrid motion vector extrapolation method, the inpainting method and the proposed method have gains of up to 4.31, 10.29, and 6.04 dB, respectively. Finally, for the situation in which the color and the depth frames are lost at the same time, our two methods jointly perform better with a gain of up to 7.79 dB.

Degradation of Bisphenol A by Peroxymonosulfate Catalytically Activated with Mn1.8Fe1.2O4 Nanospheres: Synergism between Mn and Fe

A high-efficient, low-cost, and eco-friendly catalyst is highly desired to activate peroxides for environmental remediation. Due to the potential synergistic effect between bimetallic oxides' two different metal cations, these oxides exhibit superior performance in the catalytic activation of peroxymonosulfate (PMS). In this work, novel Mn_1.8Fe_1.2O₄ nanospheres were synthesized and used to activate PMS for the degradation of bisphenol A (BPA), a typical refractory pollutant. The catalytic performance of the Mn_1.8Fe_1.2O₄ nanospheres was substantially greater than that of the Mn/Fe monometallic oxides and remained efficient in a wide pH range from 4 to 10. More importantly, a synergistic effect between solid-state Mn and Fe was identified in control experiments with Mn₃O₄ and Fe₃O₄. Mn was inferred to be the primary active site in the surface of the Mn_1.8Fe_1.2O₄ nanospheres, while Fe(III) was found to play a key role in the synergism with Mn by acting as the main adsorption site for the reaction substrates. Both sulfate and hydroxyl radicals were generated in the PMS activation process. The intermediates of BPA degradation were identified and the degradation pathways were proposed. This work is expected to help to elucidate the rational design and efficient synthesis of bimetallic materials for PMS activation.

[Using (1)H-nuclear magnetic resonance metabolomics and gene ontology to establish pathological staging model for esophageal cancer patients]

OBJECTIVES

By combining the metabolomics and computational biology, to explore the relationship between metabolic phenotype and pathological stage in esophageal cancer patients, to find the mechanism of metabolic network disturbance and develop a new method for fast preoperative clinical staging.

METHODS

A prospective cohort study (from April 2013 to January 2016) was conducted. The preoperative patients from Sichuan Provincial People's Hospital, who were diagnosed with esophageal cancer from May 2013 to April 2014 were included, and their serum samples were collected to detect (1)H-nuclear magnetic resonance (NMR) metabolomics for the purpose of drawing the metabolic fingerprinting in different stages of patients with esophageal cancer. The data were processed with these methods-principal components analysis: partial least squares regression and support vector machine, for the exploration of the enzyme-gene network regulatory mechanism in abnormal esophageal cancer metabolic network regulation and to build the quantitative prediction model of esophageal cancer staging in the end. All data were processed on high-performance computing platforms Matalab. The comparison of data had used Wilcoxon test, variance analysis, χ(2) test and Fisher exact test.

RESULTS

Twenty patients with different stages of esophageal cancer were included; and their serum metabolic fingerprinting could differentiate different tumor stages. There were no difference among the five teams in the age (F=1.086, P>0.05), the body mass index (F=1.035, P>0.05), the distance from the incisors to tumor (F=1.078, P>0.05). Among the patients with different TNM stages, there was a significant difference in plasma metabolome. Compared to ⅡB, ⅢA, Ⅳstage patients, increased levels of butanone, ethanol amine, homocysteine, hydroxy acids and estriol, together with decreased levels of glycoprotein, creatine, choline, isobutyricacid, alanine, leucine, valine, were observed inⅠB, ⅡA stage patients. Four metabolic markers (ethanol amine, hydroxy-propionic acid, homocysteine and estriol) were eventually selected. gene ontology analysis showed that 54 enzymes and genes regulated the 4 key metabolic markers. The quantitative prediction model of esophageal cancer staging based on esophageal cancer NMR spectrum were established. Cross-validation results showed that the predicted effect was good (root mean square error=5.3, R(2)=0.47, P=0.036).

CONCLUSIONS

The systems biology approaches based on metabolomics and enzyme-gene regulatory network analysis can be used to quantify the metabolic network disturbance of patients with advanced esophageal cancer, and to predict preoperative clinical staging of esophageal cancer patients by plasma NMR metabolomics.

Chondrogenesis of mesenchymal stem cells in a novel hyaluronate-collagen-tricalcium phosphate scaffolds for knee repair

Scaffolds are expected to play a key role in the induction of chondrogenesis of mesenchymal stem cells (MSCs) for cartilage tissue regeneration. Here, we report the development of a novel tricalcium phosphate-collagen-hyaluronate (TCP-COL-HA) scaffold that can function as a stem cell carrier to induce chondrogenesis and promote cartilage repair, and the investigation of chondroinductive properties of scaffolds containing varying amounts of TCP, COL and HA. TCP-COL-HA scaffolds, as well as TCP-COL scaffolds at two different TCP/COL ratios (50:50 and 25:75), were evaluated for their ability to induce cartilage regeneration from rabbit mesenchymal stem cells (rMSCs) in vitro and in vivo. Chondrogenic differentiation was evaluated by sulphated glycosaminoglycan quantification, collagen type II immunohistochemistry, and qRT-PCR. Mechanical strength was evaluated by the compression test. The results showed that the TCP-COL-HA scaffolds enhanced rMSC chondrogenesis to a greater degree than did the TCP-COL scaffolds; for the latter, the scaffold with the lower TCP/COL ratio (25:75) was superior in terms of promoting rMSC chondrogenesis. Similar results were obtained in an ectopic implantation model in nude mice. In a critical-size rabbit osteochondral defect-repair model, rMSCs seeded on TCP-COL-HA scaffolds showed greater cartilage regeneration and integration into surrounding tissue than the TCP-COL groups, in which cartilage repair was more efficient at the 25:75 than at the 50:50 ratio. These results indicate that the addition of HA and different TCP/COL ratios can affect the chondroinductive capacity of scaffolds, and suggest that the TCP-COL-HA scaffold can serve as an effective cell carrier for cartilage regeneration.

CCL3 serves as a potential plasma biomarker in knee degeneration (osteoarthritis)

OBJECTIVE

To explore the ability of chemokines in plasma to detect the presence of pre-X-rays defined knee degeneration and the extent (burden).

METHODS

A total of 181 subjects (75 control subjects, 47 pre-X-KD patients and 50 X-KOA patients) were included and subdivided into three subgroups. Articular cartilage loss in pre-X-KD patients were scored on the basis of the ICRS classification during the arthroscopy or documented on MRI with chondral WORMS. The severity of X-KOA was graded using the Kellgren-Lawrence classification through the posterior-anterior knee X-rays. The concentrations of the inflammatory cytokines and chemokines in plasma were quantified using Luminex microbead-based suspension array (SA) and were cross-validated by enzyme-linked immunosorbent assay (ELISA).

RESULTS

CCL3 in plasma showed the highest ability to discriminate pre-X-KD patients from the controls with an AUC of 0.799. At a cutoff value of 0.168 pg/ml, the sensitivity was 70.21%, the specificity was 96.00%, the positive predictive value was 91.67% and the negative predictive value was 83.72%. As to define disease burden, the plasma levels of resistin, IL6, IL8, CCL3 and CCL4 showed significant association with the severity of X-rays defined knee OA, with regard to the KL classification. Moreover, significant elevation of IL6, IL8, CCL3 and CCL4 levels in plasma were observed in severe knee OA patients (KL grade IV) compared with those with pre-X-KD (KL grade 0-I).

CONCLUSION

We firstly showed that the plasma CCL3 could be potential serum biomarker for knee OA with the capacity to detect pre-X-rays defined changes and stage the severity of damage in knee.

Multi-lineage MSC differentiation via engineered morphogen fields

Tissue loss due to oral diseases requires the healing and regeneration of tissues of multiple lineages. While stem cells are native to oral tissues, a current major limitation to regeneration is the ability to direct their lineage-specific differentiation. This work utilizes polymeric scaffold systems with spatiotemporally controlled morphogen cues to develop precise morphogen fields to direct mesenchymal stem cell differentiation. First, a simple three-layer scaffold design was developed that presented two spatially segregated, lineage-specific cues (Dentinogenic TGF-β1 and Osteogenic BMP4). However, this system resulted in diffuse morphogen fields, as assessed by the in vitro imaging of cell-signaling pathways triggered by the morphogens. Mathematical modeling was then exploited, in combination with incorporation of specific inhibitors (neutralizing antibodies or a small molecule kinase inhibitor) into each morphogen in an opposing spatial pattern as the respective morphogen, to design a five-layer scaffold that was predicted to yield distinct, spatially segregated zones of morphogen signaling. To validate this system, undifferentiated MSCs were uniformly seeded in these scaffold systems, and distinct mineralized tissue differentiation were noted within these morphogen zones. Finally, to demonstrate temporal control over morphogen signaling, latent TGF-β1 was incorporated into one region of a concentric scaffold design, and laser treatment was used to activate the morphogen on-demand and to induce dentin differentiation solely within that specific spatial zone. This study demonstrates a significant advance in scaffold design to generate precise morphogen fields that can be used to develop in situ models to explore tissue differentiation and may ultimately be useful in engineering multi-lineage tissues in clinical dentistry.

First Report of Alternaria heveae Causing Black Leaf Spot of Rubber Tree in China

Rubber tree (Hevea brasiliensis Muell. Arg.) is an important industrial crop of tropical areas for natural rubber production. In October 2013, foliar spots (0.1 to 0.4 mm in diameter), black surrounded by a yellow halo, and with lesions slightly sunken were observed on the rubber tree leaf in a growing area in Heikou County of Yunnan Province. Lesion tissues removed from the border between symptomatic and healthy tissue were surface sterilized in 75% ethanol and air-dried, plated on PDA plates, and incubated at 28°C with alternating day/night cycles of light. The pathogen was observed growing out of many of the leaf pieces, and produced abundant conidia. Colonies 6.1 cm in diameter developed on potato carrot agar (PCA) after 7 days, with well-defined concentric rings of growth. Colonies on PCA were composed of fine, dark, radiating, surface and subsurface hyphae. Conidia produced in PCA culture were mostly solitary or in short chains of 2 to 5 spores, long ovoid to clavate, and light brown, 40 to 81.25 × 8 to 20 μm (200 colonies were measured), with 3 to 6 transverse septa and 0 to 2 longitudinal or oblique septa. Morphological characteristics were similar to those described for Alternaria heveae (3,4). A disease of rubber tree caused by Alternaria sp. had been reported in Mexico in 1947 (2). DNA of Ah01HK13 isolate was extracted for PCR and sequencing of the ITS region with ITS1 and ITS4 primers was completed. From the BLAST analysis, the sequence of Ah01HK13 (GenBank Accession No. KF953884), had 97% similarity to A. dauci, 96% identical to A. macrospora (AY154701.1 and DQ156342.1, respectively), indicating the pathogen belonged to Alternaria genus. According to morphological characteristics, this pathogen was identified as A. heveae. Pathogenicity of representative isolate, Ah01HK13 was confirmed using a field rubber tree inoculation method. Three rubber plants (the clone of rubber tree Yunyan77-4) were grown to the copper-colored leaf stage and inoculated by spraying spore suspension (concentration = 10⁴ conidia/ml) to the copper-colored leaves until drops were equally distributed on it using manual pressure sprayer. Three rubber plants sprayed with sterile distilled water were used as controls. After inoculation, the plants were covered with plastic bags. The plastic bags were removed after 2 days post-inoculation (dpi) and monitored daily for symptom development (1). The experiment was repeated three times. The typical 0.1 to 0.4 mm black leaf spots were observed 7 dpi. No symptoms were observed on control plants. A fungus with the same colony and conidial morphology as A. heveae were re-isolated from leaf lesions on inoculated rubber plants, but not from asymptomatic leaves of control plants, fulfilling Koch's postulates. Based on these results, the disease was identified as black spot of rubber tree caused by A. heveae. To our knowledge, this is the first report of A. heveae on rubber tree in China. References: (1) Z. Y. Cai et al. Microbiol Res. 168:340, 2013. (2) W. J. Martin. Plant Dis. Rep. 31:155, 1947. (3) E. G. Simmons. Mycotaxon 50:262, 1994. (4) T. Y. Zhang. Page 111 in: Flora Fungorum Sinicorum: Alternaria, Science Press, Beijing, 2003.

Distribution and pathogen identification of cassava brown leaf spot in China

Cassava brown leaf spot surveys were conducted in the main cassava plantation areas of China between 2007 and 2012 in order to understand the distribution of the disease. Cassava plants were damaged by the disease to different degrees in most of the survey sites. Samples were collected and seven strains were isolated from lesions. The mycelium-breaking plus black light induction method was applied for sporulation. Microconidia were formed by means of fragmentation on artificial medium plates. When the leaf was stabbed and inoculated with conidia solution, similar symptoms were formed 14 days later. Morphological characteristics of the specimens and conidia were similar to descriptions of Passalora henningsii infection. The internal transcribed spacer (ITS) regions of rDNA were obtained with primer pair ITS1/ITS4 and deposited in GenBank, which differed by three base pairs from that of the P. henningsii isolate (AF284389). The ITS sequences of related species were downloaded from the NCBI database, and phylogenetic analysis showed that the sequences originating from our strains clustered in the same clade as the AF284389 isolate. Biological characteristics were evaluated in two strains from different sites, which indicated that the optimum conditions for mycelia growth were a temperature of 26° to 28°C, carrot agar medium, pH 6, and continuous dark; cassava leaf juice added to malt extract and cassava leaf juice added to potato dextrose agar were the best media for conidia production. The optimal and lethal temperatures for macroconidia germination were 26° to 28°C, and 60°C for 10 min, respectively.

Strongly interacting photons in asymmetric quantum well via resonant tunneling

We propose an asymmetric quantum well structure to realize strong interaction between two slow optical pulses. The essential idea is the combination of the advantages of inverted-Y type scheme and resonant tunneling. We analytically demonstrate that giant cross-Kerr nonlinearity can be achieved with vanishing absorptions. Owing to resonant tunneling, the contributions of the probe and signal cross-Kerr nonlinearities to total nonlinear phase shift vary from destructive to constrictive, leading to nonlinear phase shift on order of π at low light level. In this structure, the scheme is inherent symmetric for the probe and signal pulses. Consequently, the condition of group velocity matching can be fulfilled with appropriate initial electron distribution.

[p16 and cyclinD1 protein expression and p16 gene mutation in primary human hepatocellular carcinoma]

OBJECTIVE

To elucidate the relationship between expression of p16 and cyclinD1 proteins and evaluate the role of p16 gene exon 2 mutation in hepatocellular carcinogenesis.

METHODS

Streptavidin-peroxidase conjugated method(SP) was used to detect expressions of p16 and cyclinD1 proteins in 44 cases of hepatocellular carcinoma(HCC), and polymerase chain reaction single-strand conformation polymorphism analysis(PCR-SSCP) to detect p16 gene mutation in exon 2 in 12 cases of HCC and liver tissues adjacent to HCC.

RESULTS

Expression rate and positive signal intensity of p16 protein in HCC were significantly lower(P < 0.01) and those of cyclinD1 protein in HCC were significantly higher (P < 0.05) than those in pericarcinomatous tissues. Of 12 fresh HCC tissues, p16 gene mutation in exon 2 was found in 2 cases, whereas that was not found in pericarcinomatous tissues.

CONCLUSIONS

1. Inactivation or/ and deletion of p16 protein may be one of important reasons which result in proliferation unbalance of cells. 2. p16 gene mutation in exon 2 presents in HCC, but it does not frequently occur in Chinese hepatocarcinogenesis. 3. p16 gene abnormality and cyclinD1 over expression may coact in HCC.

[Modified breast reconstruction by latissimus dorsi musculocutaneous flap]

OBJECTIVE

To investigate the effect of breast reconstruction with latissimus dorsi musculocutaneous flap.

METHODS

Since 1994, 60 cases were performed breast reconstruction with latissimus dorsi musculocutaneous flap with fat tissue nourished by thoracodorsal artery according to the shape and volume of the normal breast on the other side. All of cases were followed up for 3 months to 5 years.

RESULTS

Among the 60 cases, excellent effect was obtained in 41 cases (68.3%), good effect in 16 cases (26.7%), unsatisfactory in 3 cases (5.0%).

CONCLUSION

Modified latissimus dorsi musculocutaneous flap to reconstruct breast overcome the shortcoming of volume deficiency of traditional latissimus dorsi in breast reconstruction, and it is a safe and easy-manipulated surgical operation.