Metal-coated high-temperature strain optical fiber sensor based on cascaded air-bubble FPI-FBG structure.

Metal coatings can protect the fragile optical fiber sensors and extend their life in harsh environments. However, simultaneous high-temperature strain sensing in a metal-coated optical fiber remains relatively unexplored. In this study, a nickel-coated fiber Bragg grating (FBG) cascaded with an air bubble cavity Fabry-Perot interferometer (FPI) fiber optic sensor was developed for simultaneous high temperature and strain sensing. The sensor was successfully tested at 545 °C for 0-1000 µÉ›, and the characteristic matrix was used to decouple temperature and strain. The metal layer allows easy attachment to metal surfaces that operate at high temperatures, enabling sensor-object integration. As a result, the metal-coated cascaded optical fiber sensor has the potential to be used in real-world structural health monitoring.

Temperature-decoupled hydrogen sensing with Pi-shifted fiber Bragg gratings and a partial palladium coating.

A novel, to the best of our knowledge, sensor architecture for palladium-coated fiber Bragg gratings is proposed and demonstrated that allows highly accurate multi-parameter sensing and decoupling of hydrogen concentration from temperature. By means of partly Pd-coated Pi-shifted FBGs (PSFBGs), the notch wavelength of the narrow transmission band and the flank wavelength of the broader reflection band experience different hydrogen and temperature sensitivities. PSFBGs were calibrated at hydrogen concentrations between 800 and 10,000 ppm and temperatures from 20 to 40°C, and a decreased hydrogen sensitivity at increased temperatures was found. Nonlinear temperature-dependent hydrogen calibration functions were therefore determined. An iterative matrix algorithm was used to decouple hydrogen concentration and temperature and to account for the nonlinear calibration functions. Achieved improvements and results have great importance for real field applications of FBG-based hydrogen sensing.

Access to N-Alkylazaheterocyclic Salts by Activation of Alkoxy C-O Bonds in Polyol Esters.

A wide variety of N-alkylazaheterocyclic salts are conveniently synthesized from polyol esters and azaheterocyclic salts under solventless conditions. In particular, paraquat-like derivatives showed comparable herbicidal activity toward several common weeds. Mechanistic studies suggest that polyesters likely underwent partial hydrolysis and neighboring group participating dehydration under the action of acidic salt to generate five-membered ring intermediates, which reacted with the azaheterocycle to accomplish the N-alkylation.

Comparative study of characteristic compounds of three species of truffle.

The Panxi area in Sichuan Province is the main area for the production of truffles in China, and several species of truffle are known to exist in this region. Nevertheless, it is unclear what the differences in chemical composition between the truffles are. Using an ultra-high-performance liquid chromatography quadrupole/orbitrap high-resolution mass spectrometry coupled with Compound Discoverer 3.0, we identified chemical components in three mainly known truffles from the Panxi region. Further analysis of chemical composition differences was conducted using principal component analysis, and orthogonal partial least squares discriminant analysis. Note that, 78.9% of the variance was uncovered by the principal component analysis model. As a result of the orthogonal partial least squares discriminant analysis model, the three species of truffles (Tuber pesudohimalayense, Tuber indicum, and Tuber sinense) from Panxi were better discriminated, with R2 X, R2 Y, and Q2 being 0.821, 0.993, and 0.947, respectively. In this study, 87 components were identified. T. pesudohimalayense contained significantly higher levels of nine different compounds than the other two species. Hence, it was possible to identify similarities and differences between three species of truffles from Panxi in terms of chemical composition. This can be used as a basis for quality control.

Design, Synthesis, Antifungal Activity, and Molecular Docking of Streptochlorin Derivatives Containing the Nitrile Group.

Based on the structures of natural products streptochlorin and pimprinine derived from marine or soil microorganisms, a series of streptochlorin derivatives containing the nitrile group were designed and synthesized through acylation and oxidative annulation. Evaluation for antifungal activity showed that compound 3a could be regarded as the most promising candidate-it demonstrated over 85% growth inhibition against Botrytis cinerea, Gibberella zeae, and Colletotrichum lagenarium, as well as a broad antifungal spectrum in primary screening at the concentration of 50 µg/mL. The SAR study revealed that non-substituent or alkyl substituent at the 2-position of oxazole ring were favorable for antifungal activity, while aryl and monosubstituted aryl were detrimental to activity. Molecular docking models indicated that 3a formed hydrogen bonds and hydrophobic interactions with Leucyl-tRNA Synthetase, offering a perspective for the possible mechanism of action for antifungal activity of the target compounds.

Design of OMC-Sagnac Loop Using PDMS and Different Package Structures to Improve Sensing Performance and Optimize the Ill-Conditioned Matrix.

In the process of ocean exploration, highly accurate and sensitive measurements of seawater temperature and pressure significantly impact the study of seawater's physical, chemical, and biological processes. In this paper, three different package structures, V-shape, square-shape, and semicircle-shape, are designed and fabricated, and an optical microfiber coupler combined Sagnac loop (OMCSL) is encapsulated in these structures with polydimethylsiloxane (PDMS). Then, the temperature and pressure response characteristics of the OMCSL, under different package structures, are analyzed by simulation and experiment. The experimental results show that structural change hardly affects temperature sensitivity, and square-shape has the highest pressure sensitivity. In addition, with an input error of 1% F.S., temperature and pressure errors were calculated, which shows that a semicircle-shape structure can increase the angle between lines in the sensitivity matrix method (SMM), and reduce the effect of the input error, thus optimizing the ill-conditioned matrix. Finally, this paper shows that using the machine learning method (MLM) effectively improves demodulation accuracy. In conclusion, this paper proposes to optimize the ill-conditioned matrix problem in SMM demodulation by improving sensitivity with structural optimization, which essentially explains the cause of the large errors for multiparameter cross-sensitivity. In addition, this paper proposes to use the MLM to solve the problem of large errors in the SMM, which provides a new method to solve the problem of the ill-conditioned matrix in SMM demodulation. These have practical implications for engineering an all-optical sensor that can be used for detection in the ocean environment.

Generalized and wavelength-dependent temperature calibration function for multipoint regenerated fiber Bragg grating sensors.

A new calibration methodology for regenerated fiber Bragg grating (RFBG) temperature sensors up to 700 °C is proposed and demonstrated. A generalized, wavelength-dependent temperature calibration function is experimentally determined that describes the temperature-induced wavelength shifts for all RFBG sensor elements that are manufactured with the same fabrication parameters in the wavelength range from 1465 nm to 1605 nm. Using this generalized calibration function for absolute temperature measurements, each RFBG sensor element only needs to be calibrated at one reference temperature, representing a considerable simplification of the conventional calibration procedure. The new calibration methodology was validated with 7 RFBGs, and uncertainties were found to be compliant with those of Class 1 thermocouples (< ±1.5 K or < ±0.4% of the measured temperature). The proposed calibration technique overcomes difficulties with the calibration of spatially extended multipoint RFBG sensor arrays, where setting up an adequate calibration facility for large sensor fibers is challenging and costly. We assume that this calibration method can also be adapted to other types of FBG temperature sensors besides RFBGs. An accurate and practical calibration approach is essential for the acceptance and dissemination of the fiber-optic multipoint temperature sensing technology.

Temperature and external strain sensing with metal-embedded optical fiber sensors for structural health monitoring.

An optical fiber with both temperature and strain fiber Bragg grating sensors were embedded into an aluminum cast structure during the casting process. Temperature and strain calibrations were carried out respectively for the metal-embedded sensors. Temperature and external strain decoupling was further demonstrated in a temperature range from 25 to 80 °C and an external strain range from 0 to ∼110 µÉ›. With the interpolated temperature measured by two temperature sensors at different positions, the external strain could be decoupled from temperature and thermal strain at the strain sensor. The temperature and external strain values obtained from our embedded optical fiber sensors agreed well with reference values, revealing the good performance of the metal-embedded optical fiber sensors. The difference between the measured values and the reference values are within ±5 µÉ› for external strain and ±1 °C for temperature. With only a single fiber, the in-situ temperature and external strain information in the aluminum structure can be monitored in real time, representing an important step towards fiber-optic smart casts. Our investigation demonstrates that embedded optical fiber sensors can be a promising method for structural health monitoring of metallic structures.

High-performance temperature and pressure dual-parameter sensor based on a polymer-coated tapered optical fiber.

Based on the polymer encapsulation method, a compact structure and high-sensitivity temperature and pressure dual parametric sensor was developed in this paper by wrapping an optical microfiber coupler (OMC) in polydimethylsiloxane (PDMS). Benefiting from the stable chemical properties and good optical field control ability of PDMS, the sensor showed good stability and repeatability. The dependence of the sensor sensitivity on wavelength, temperature, and pressure was experimentally investigated. The results showed that the temperature and pressure sensitivity could reach -2.283 nm/°C and 3.301 nm/Mpa in the C-band range. To overcome the cross-sensitivity of sensor temperature and pressure, a sensitivity matrix was established to realize dual-parameter simultaneous demodulation. In addition, the pressure repeatability of the sensor was tested. Based on this, the sensitivity matrix was further calibrated to reduce the error and improve the accuracy of demodulation. Finally, we also designed a protective shell for the sensor to meet the requirements of practical marine applications. Compared with other existing types of optical fiber sensors, this sensor has the advantages of simple fabrication, high sensitivity, and environmental adaptability, and has great potential for application in the field of marine environmental monitoring.

Design of photonic crystal fiber to excite surface plasmon resonance for highly sensitive magnetic field sensing.

To improve the sensing performance of optical fiber magnetic field sensor based on magneto-refractive effect, a D-shaped photonic crystal fiber-surface plasmon resonance (PCF-SPR) sensor based on magneto-refractive effect is proposed and its magnetic field sensing characteristics are investigated. The designed D-shaped PCF has a core-analyte-gold structure. Within the D-shaped PCF, the side polishing surface is coated with the gold film and the special hole is sandwiched between the core and the gold film. To realize the high magnetic field sensitivity for the fiber SPR magnetic field sensor, the special hole is filled with magnetic fluid (MF). In this paper, we analyze the mode transmission characteristics and magnetic field sensing characteristics of this fiber sensor by finite element method. We also obtain a general rule for the optimization of PCF-SPR sensors by analyzing the dispersion curves, the energy of the surface plasmon polariton mode and the core mode on the sensing performance of the designed fiber sensor. The maximum refractive index sensitivity and magnetic field sensitivity of the optimized fiber are 59714.3 nm/RIU and 21750 pm/mT (50-130 Oe), respectively. Compared with optical fiber magnetic field sensors based on magneto-refractive effect reported previously, the magnetic field sensitivity in this paper is nearly two orders of magnitude higher and it can initially achieve nT magnitude magnetic field resolution and testing capability. The proposed fiber sensor has the advantages of simple structure, easy production, high sensitivity, and strong environmental adaptability. It not only improves the sensing performance of optical fiber magnetic field sensors, but also provides an ideal alternative platform for biosensors like microfluidics because of its high refractive index sensitivity and the special structure.

Four-Component Reaction Access to Nitrile-Substituted All-Carbon Quaternary Centers.

A four-component reaction strategy for access to acyclic nitrile-substituted all-carbon quaternary centers is disclosed. In the presence of a DABCO-based ionic liquid catalyst, the reactions proceed smoothly with a wide range of substrates efficiently to deliver nitrile-substituted all-carbon quaternary centers under mild reaction conditions. This protocol is further demonstrated as an efficient method for the construction of contiguous all-carbon quaternary centers. All the reactions are easily operated in a green manner, producing water as the only byproduct. Some of the products show excellent activity against specific fungi.

Decentering the Symmetry via Docking B and F in the KBe2BO3F2-Family Structure.

Deep-ultraviolet (DUV; <200 nm) nonlinear optical crystals arouse a great research interest in modern optical material science as they are key parts of solid-state lasers. Since KBe2BO3F2 (KBBF) still is the only crystal which can generate DUV coherent light practically, exploring other available structures in the DUV region by revising KBBF-family structure templates is necessary. In this paper, two KBBF-family structures are designed by adjusting the directions of BO3 groups or docking B and F atoms in known ß-Be2BO3F (BBF). The first BBF structure with a P6322 space group is designed by strictly aligning the BO3 groups of even layers and odd layers in ß-BBF. It is very interesting that docking B and F atoms forms novel B-F bonds, which destroy the inversion symmetry of the structure, making the centrosymmetric ß-BBF structure with the R3̅c space group convert to a noncentrosymmetric BBF structure having the R3c space group. This noncentrosymmetric BBF structure exhibits a DUV cutoff edge shorter than 150 nm and a second harmonic generation effect comparable to that of KH2PO4 (KDP; d36 = 0.39 pm/V), indicating its feasibility as a frequency-doubling crystal in the DUV region. Our conversion design provides an effective way for uncovering noncentrosymmetric structures in KBBF-family structures.

Two-channel photonic crystal fiber based on surface plasmon resonance for magnetic field and temperature dual-parameter sensing.

In this paper, a dual-parameter sensor based on surface plasmon resonance (SPR)-photonic crystal fiber (PCF) is proposed, which can be applied in detecting the magnetic field and temperature. In this sensor, two elliptical channels are designed on both sides of the fiber core. The left channel (Ch 1) is coated with gold film and filled with magnetic fluid (MF) to achieve a response to the magnetic field and temperature using SPR. The right channel (Ch 2) is coated with gold film as well as Ta2O5 film to improve the SPR sensing performance. Finally, Ch 2 is filled with polydimethylsiloxane (PDMS) to achieve a response to the temperature. The mode characteristics, structural parameters and sensing performance are investigated by the finite element method. The results show that when the magnetic field is in the range of 50-130 Oe, the magnetic field sensitivities of Ch 1 and Ch 2 are 65 pm Oe-1 and 0 pm Oe-1, respectively. When the temperature is in the range of 17.5-27.5 °C, the temperature sensitivities of Ch 1 and Ch 2 are 520 pm °C-1 and 2360 pm °C-1, respectively. By establishing and demodulating a sensing matrix, the sensor can not only measure the temperature and magnetic field simultaneously but also solve the temperature cross-sensitivity problem. In addition, when the temperature exceeds a certain value, the proposed sensor is expected to achieve dual-parameter sensing without a matrix. The proposed dual-parameter SPR-PCF sensor has a unique structure and excellent sensing performance, which are important for the simultaneous sensing of multiple basic physical parameters.

Designing A New Infrared Nonlinear Optical Material, ß-BaGa2 Se4 Inspired by the Phase Transition of the BaB2 O4 (BBO) Crystal.

Infrared nonlinear optical (IR NLO) crystals play a significant role in the development of IR laser technology. But rationally designing a new IR NLO crystal remains a huge challenge because of the unpredictability of inorganic structures. Herein, inspired by phase transformation of the famous BaB2 O4 (BBO) crystal, a temperature-induced centrosymmetric (CS) to noncentrosymmetric (NCS) transformation approach is employed in CS BaGa2 Se4 to uncover a new NCS ternary chalcogenide, ß-BaGa2 Se4 which can exhibit the well-balanced NLO properties, including moderate phase-matching SHG response (≈0.6×AgGaS2 ), high LDT (10×AgGaS2 ), and large birefringence (Δn=0.18 in the visible region). Therefore, ß-BaGa2 Se4 will be a promising IR NLO crystal. The analysis for the structure-property relationship shows that the excellent NLO properties of ß-BaGa2 Se4 mainly originate from edge-sharing GaSe4 tetrahedral chains, which are different from B3 O6 groups in ß-BBO and respect a new direction for the design of IR NLO crystals. So, we believe that the current research provides not only a new IR NLO crystal but also some insights for the design of new IR NLO crystals.

Coassembly of hypoxia-sensitive macrocyclic amphiphiles and extracellular vesicles for targeted kidney injury imaging and therapy.

BACKGROUND: Hypoxia is a major contributor to global kidney diseases. Targeting hypoxia is a promising therapeutic option against both acute kidney injury and chronic kidney disease; however, an effective strategy that can achieve simultaneous targeted kidney hypoxia imaging and therapy has yet to be established. Herein, we fabricated a unique nano-sized hypoxia-sensitive coassembly (Pc/C5A@EVs) via molecular recognition and self-assembly, which is composed of the macrocyclic amphiphile C5A, the commercial dye sulfonated aluminum phthalocyanine (Pc) and mesenchymal stem cell-excreted extracellular vesicles (MSC-EVs). RESULTS: In murine models of unilateral or bilateral ischemia/reperfusion injury, MSC-EVs protected the Pc/C5A complex from immune metabolism, prolonged the circulation time of the complex, and specifically led Pc/C5A to hypoxic kidneys via surface integrin receptor α4ß1 and αLß2, where Pc/C5A released the near-infrared fluorescence of Pc and achieved enhanced hypoxia-sensitive imaging. Meanwhile, the coassembly significantly recovered kidney function by attenuating cell apoptosis, inhibiting the progression of renal fibrosis and reducing tubulointerstitial inflammation. Mechanistically, the Pc/C5A coassembly induced M1-to-M2 macrophage transition by inhibiting the HIF-1α expression in hypoxic renal tubular epithelial cells (TECs) and downstream NF-κB signaling pathway to exert their regenerative effects. CONCLUSION: This synergetic nanoscale coassembly with great translational potential provides a novel strategy for precise kidney hypoxia diagnosis and efficient kidney injury treatment. Furthermore, our strategy of coassembling exogenous macrocyclic receptors with endogenous cell-derived membranous structures may offer a functional platform to address multiple clinical needs.

First Report of Diaporthe longicolla Causing Leaf Spot on Kalanchoe pinnata in China.

Kalanchoe pinnata (Lam.) Pers. [syn.: Bryophyllum pinnatum (Lam.) Oken] is an important medicinal agent in southern China. The succulent leaves of this plant are used in the treatment of cholera, bruises, uri-nary diseases and whitlow. In Oct. 2019, leaf spots were detected on K. pinnata plants in Chengmai County, Hainan Province, China. Lesions with brown to black margins were irregularly shaped and associated with leaf margins. Spots coalesced to form larger lesions (Fig. S1-A), with black pycnidia present in more mature lesions. Symptomatic K. pinnata were found with 10-20% incidence during the humid winters of Hainan Province. Leaf tissues of 10 symptomatic plants were collected and surface sterilized in 70% ETOH for 30s, 0.1% HgCl2 for 30 s, rinsed 3x with sterile distilled water for 30s, placed on potato dextrose agar (PDA) amended with 30mg/L of kanamycin sulfate, and incubated at 25°C in the dark for 3-5 days. Four fungal isolates were obtained using a single-spore isolation method. The colonies were floccose, dense, and white with forming on older colonies grown on PDA (Fig. S1-B-1&2). Alpha conidia exuded from ostiole, rostrate, long-beaked pycnidia in creamy-to-yellowish drops. Alpha conidia were hyaline, ellipsoidal, separated and averaged 6.3µm (SD ± 1.13) long × 1.9µm (SD ± 0.33) wide (n=50). Beta conidia were not seen. The morphological characteristics matched the previous description of Diaporthe longicolla (syn. Phomopsis longicolla) (Hobbs et al. 1985). Mycelial genomic DNA of the representative isolate LDSG3-2 was extracted as template. The internal transcribed spacer (ITS) , translation elongation factor 1α gene (TEF) and ß-tubulin (TUB2) regions were amplified. These loci were amplified using primer pairs ITS4/ITS5 (White, et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn 1999) and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. A BLAST search of GenBank showed ITS (MN960195), TEF (MN974483) and TUB2 (MN974482) sequences of the isolate were 99%, 100%, and 99% homologous with D. longicolla strains DL11 (MF125048, 557/563 bp), D55 (MN584792, 347/347 bp) and DPC-HOH-32 (MK161506, 502/504 bp). Maximum likelihood trees based on concatenated nucleotide sequences of the three genes were constructed using MEGA 7.0, and bootstrap values indicated the isolate was D. longicolla (Fig. S1-D). Pathogenicity testing was performed using isolate LDSG3-2 by depositing 5µl droplets of a conidial suspension (1 × 106 ml-1) into 5 artificially wounded leaves (using a sterile needle) of 10 healthy 3-month-old K. pinnata plants. An equal number of artificially wounded control leaves were inoculated with sterile water to serve as a negative control. The test was conducted three times. Plants were kept at 25°C in 80% relative humidity and observed for symptoms. Two weeks after inoculation, no symptoms were observed on control plants (Fig. S1-C-1) and all inoculated plants showed symptoms (Fig. S1-C-2) similar to those observed in the field. The fungus was re-isolated from the infected tissues and showed the same cultural and morphological characteristics of the strain inoculated and could not be isolated from the controls fulfilling Koch's postulates. To our knowledge, this is the first report of leaf spot on K. pinnata caused by D. longicolla in China. This disease is of concern since Phomopsis diseases are common in K. pinnata fields and can cause significant reduction in yield. References: White, T. J., et al. 1990. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. DOI: 10.1016/0167-7799(90)90215-J Carbone, I., and Kohn, L. M. 1999. Mycologia. 91:553. DOI: 10.2307/3761358 Glass, N. L., and Donaldson, G. C. 1995. Appl. Environ. Microbiol. 61:1323. DOI: 10.1002/bit.260460112 Hobbs, T. W. et al. 1985. Mycologia. 77: 535. DOI: 10.2307/3793352.

First Record of Leaf Spot Disease on Costus speciosus Caused by Nigrospora oryzae in Hainan, China.

Costus speciosus (Koen.) Smith has been an important medicinal agent in the various traditional and folk systems of medicine in southern China. In September 2018, leaf spot disease was detected on C. speciosus plants in Chengmai County, Hainan Province. A survey of C. speciosus plants revealed that the disease caused serious damage during the typhoon season of September to November in Hainan Province, with 80 to85% incidence in plants. Early symptoms were yellow-to-brown, irregular-shaped lesions on the leaf margin or tip. After several days, lesions expanded along the mid-vein until the entire leaf was destroyed. Then, the infected leaves turned gray brown, leading to defoliation. Heavily infected leaves became dry and died. The pathogen was consistently isolated from the lesions and pure single-spore cultures were obtained. Twenty pieces of diseased leaf samples were plated and seven pieces yielded fungal colonies after 5 to 6 days of incubation at 25 °C. Colonies on potato dextrose agar (PDA) were white and later became gray to black. Conidia were unicellular, terminal, black, elliptical that measured 10 to 13 (length) × 12 to 16 (width) µm (n=30), growing aerial mycelium covering the entire petri dish (9 cm in diameter). The morphological characteristics and measurements of this fungal pathogen matched the previous descriptions of Nigrospora oryzae (Wang et al. 2017). To confirm identity the internal transcribed spacer (ITS) region of the ribosomal DNA was amplified using primers ITS1/ITS4 (Mills, P. R., et al. 1992), and the 530-bp product (GenBank Accession No. MK280694) of the ITS showed 99% sequence identity to N. oryzae isolates TLFa21 (GenBank Accession No. MH790146) and xsd08022 (GenBank Accession No. EU918714). Pathogenicity tests were conducted. Three leaves of three C. speciosus plants were wounded and inoculated with mycelial plugs (5×5mm) , and an additional five plants were inoculated with PDA plugs as a control. All plants were placed in the field and temperature ranged from 23 to 29°C. Ten days after inoculation, all the inoculated plants showed typical leaf spot symptoms, a yellow-to-brown mildew appeared at the points of inoculation. No symptoms were observed on the controls. The fungus was re-isolated from the infected tissues, fulfilling Koch's postulates. N. oryzae was previously reported as the causal agent of leaf spot on cotton (Zhang. et al. 2012), dendrobium candidum (Wu. et al. 2014) and Aloe vera (Zhai. et al. 2013) in china. To our knowledge, this is the first report of leaf spot of C. speciosus caused by N. oryzae in China. The project was partially founded by Hainan Provincial Research Institute of technology development projects (Screening and application of endophytic bacteria with high resistance to Fusarium Wilt of Sauropus androgynus), Hainan Provincial Key Laboratory for Vegetables and Biology，Hainan Provincial Engineering Research Center for Melon and Vegetable Breeding, Major scientific and technological projects in Hainan Province(ZDKJ2017001)，Third Survey and Collection of Crop Germplasm Resources in China, Collection, identification and preservation of pathogenic bacteria of inverted season vegetable in Hainan. References: L. F. Zhai., et al.2013. Plant Dis.97:1256 L. X. Zhang., et al.2012. Plant Dis.102:2029 J. B. Wu., et al.2014. Plant Dis.98:996 Mills, P. R., et al. 1992. FEMS Microbiol Lett. 98:137-144 Wang et al. 2017. Persoonia 39: 118-142.

First Report of Colletotrichum gloeosporioides Causing Anthracnose on Canna edulis Ker in China.

Canna edulis Ker has been an important economic plant in southern China. The tuberous stems are the most valued plant part and in the past were routinely used as animal feeds. In June 2019, leaf spot disease were detected on C. edulis plants in Chengmai, Hainan Province. Symptoms of the disease were characterized by oval-shaped, initially pale to yellow lesions that become necrotic (brown) with yellow borders, As the lesions expanded, the disease could encompass the entire leaves. which were seen as concentric rings typical of anthracnose disease (FigS1-A). A survey of C. edulis plants revealed that the disease caused serious damage during the summer in Hainan Province, with 50 to 60% incidence in plants. To isolate the pathogen, ten pieces of diseased leaf samples were plated and seven pieces yielded fungal colonies after 5 to 6 days of incubation at 25 °C. The Colonies were single-spored to obtain pure cultures. Pure cultures on potato dextrose agar (PDA) appear white to gray, with white margins and aerial hyphae, and the reverse of the colonies was gray to brown (FigS1-B). Conidia were single-celled, hyaline, cylindrical to slightly curved with a rounded apex and truncated base that measured 13.3 to 18.1(length) × 3.7 to 5.5 (width) µm (n=50) (FigS1-C). The morphological characteristics and measurements of this fungal pathogen matched the previous descriptions of Colletotrichum gloeosporioides (Prihastuti et al. 2012). Isolate JO-3 was identicated by molecular analysis, sequences of the internal transcribed spacer (ITS), actin (ACT) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) regions were obtained. These loci were amplified from isolates using the primer pairs ITS1/ITS4 (Mills et al. 1992), ACT-512F/ ACT-783R (Weir et al. 2012) and GDF/GDR (Templeton et al. 1992) respectively. A BLAST search of GenBank showed that the ITS (MN913584), ACT(MN919196) and GAPDH (MN919195) sequences of the isolate were 99% , 100% and 100% homologous with C. gloeosporioides (GenBank accession nos. MH930419, JX009931 and KX885158). Maximum likelihood trees based on concatenated sequences of the three genes were constructed using MEGA7.0. The results showed the strains isolated from C. edulis were closely related to C. gloeosporioides, as supported by high bootstrap values (FigS1-D). Pathogenicity test was performed with isolate JO-3 by depositing 10-µl droplets of a suspension (1 × 106 conidia/ml) on the surfaces of five artificially wounded leaves (a small hole made with a pushpin) of ten healthy 1-year-old C. edulis plants. An equal number of control leaves were inoculated with sterile water to serve as a negative control. The test was conducted three times. Plants were kept at 25°C with 80% humidity and observed for symptom every day. One weeks after inoculation, all the inoculated plants showed symptoms of yellow sunken spots similar to those observed in the field. No symptoms were observed on the controls. The fungus re-isolated from the infected tissues showed the same cultural and morphological characteristics of the strain inoculated, fulfilling Koch's postulates. C. gloeosporioides was previously reported as the causal agent of anthracnose on Hymenocallis littoralis (Zhao et al. 2019), Abelmoschus esculentus (L.) Moench (Shi et al. 2019) and Sorbaria sorbifolia (Li et al. 2019) in China. To our knowledge, this is the first report of anthracnose on C. edulis caused by C. gloeosporioides in China. This disease can seriously affect the yield and quality of C. edulis in China. Given its wide host range, C. gloeosporioides has great potential to become an economically important plant pathogen. The project was partially funded by Hainan Provincial Research Institute of technology development projects (Collection, Evaluation and Domestication Cultivation of Wild Vegetable Germplasm Resources in Hainan), Hainan Provincial Key Laboratory for Vegetables and Biology，Hainan Provincial Engineering Research Center for Melon and Vegetable Breeding, Major scientific and technological projects in Hainan Province(ZDKJ2017001)，Key R & D projects in Hainan Province (ZDYF2019066), The third Survey and Collection of Crop Germplasm Resources in China. References: Mills, P. R., et al. 1992. FEMS Microbiol Lett. 98:137-144 Weir, B. S., et al. 2012. Stud. Mycol. 73:115. Templeton, M.D. et al. 1992. Gene. 122:225. Prihastuti, H., et al. 2009. Fungal Divers. 39:89 C. D. Zhao, et al. 2019. Plant Dis.103:3286 Y. X. Shi, et al. 2019. Plant Dis.103:303 X. Y. Li, et al. 2019. Plant Dis.103:242.

Sensitivity of Puccinia graminis f. sp. tritici Isolates From China to Triadimefon and Cross-Resistance Against Diverse Fungicides.

Wheat stem rust caused by Puccinia graminis f. sp. tritici is an important wheat disease with sudden and devastating characteristics. The appearance and spread of new P. graminis f. sp. tritici races (Ug99, TKTTF, and TTTTF) have once again renewed the interest in the prevention and control of wheat stem rust. Fungicides can effectively control the epidemics of this disease in a short period of time. However, the fungal pathogen is prone to developing resistance. Therefore, we collected 89 isolates of P. graminis f. sp. tritici from four provinces in China and used the spore germination method to test the sensitivity of the isolates to fungicide triadimefon. Seven relatively triadimefon-sensitive isolates and six relatively triadimefon-resistant isolates were further tested for sensitivity to fungicides carbendazim, mancozeb, thiophanate-methyl, and kresoxim-methyl. The results showed that the mean concentration for 50% of maximal effect of the isolates to triadimefon was 16.14 mg·liter-1, and the mean resistance factor was 4.48. Only 29 isolates were resistant to triadimefon in which 27 isolates had low levels of resistance and 2 isolates had moderate levels of resistance. However, most of the 89 isolates had no resistance to triadimefon. There was a positive correlation between resistance to triadimefon and carbendazim, but there was no cross-resistance between triadimefon resistance with thiophanate-methyl or kresoxim-methyl resistance. This study provides valuable information for managing fungicide resistant isolates of P. graminis f. sp. tritici.

Prediction and Characterization of NaGaS2, A High Thermal Conductivity Mid-Infrared Nonlinear Optical Material for High-Power Laser Frequency Conversion.

Infrared nonlinear optical (IR NLO) crystals are the major materials to widen the output range of solid-state lasers to mid- or far-infrared regions. The IR NLO crystals used in the middle IR region are still inadequate for high-power laser applications because of deleterious thermal effects (lensing and expansion), low laser-induced damage threshold, and two-photon absorption. Herein, the unbiased global minimum search method was used for the first time to search for IR NLO optical materials and ultimately found a new IR NLO material NaGaS2. It meets the stringent demands for IR NLO materials pumped by high-power laser with the highest thermal conductivity among common IR NLO materials able to avoid two-photon absorption, a classic nonlinear coefficient, and wide infrared transparency.