Eddy Effect and Dynamic Response of High-Speed Solenoid Valve with Composite Iron Core.

To alleviate the Eddy effect of the high-speed solenoid valve (HSV) and improve its dynamic response speed, a novel HSV with a composite iron core is presented. The time-step finite element method is used to establish and verify the numerical simulation of HSV coupling multiple physical fields. Then, the Eddy effect and dynamic response characteristics of the conventional and composite HSVs are further compared and analyzed. The results showed that the Eddy current loss in the main pole was the largest for the conventional HSV, accounting for 72.5% and 64.4% in the actuation and release processes, respectively. It was found that the Eddy effect of the composite HSV was obviously weakened, and the total Eddy current losses in the actuation and release processes were reduced by 58.8% and 38.7%, respectively. Meanwhile, the actuation response time and release response time of the composite HSV were shortened by 15.6% and 18.5%, respectively. In addition, increasing the peak voltage further shortened the actuation response time of the composite HSV, but had no significant effect on the response time of the conventional HSV.

First Report of Anthracnose Caused by Colletotrichum sansevieriae on Sansevieria trifasciata var. laurentii in China.

Sansevieria trifasciata var. laurentii (De Wild.) N.E. Brown, commonly known as variegated snake plant or variegated mother-in-law's tongue, is a popular landscape and house plant. In September and October 2019, the obvious leaf spot symptoms were observed on the plants in a 0.2 hm2 of nursery in Qingdao city of China with incidence of 55%. The disease usually starts from the tip or edge of the leaf, initially have slightly water-soaked semi-circular or round brown lesions, which gradually expanded and coalesced into irregular shapes about 3-8 cm in diameter. Grayish brown sunken spots with dark margins that evolve into concentric rings of acervuli which were characteristic of anthracnose, and orange sticky conidial masses were observed under the moist condition. The leaves with typical anthracnose symptoms were collected and deposited in the herbarium of Qingdao agricultural university under accessions no. QDHB074-QDHB087. Subsequently 20 isolates with the same colony and morphological characteristics were obtained from ten diseased leaves by placing surface-sterilized tissue pieces with typical spots on potato dextrose agar (PDA). Colonies are floccose with grayish-white to dark olivaceous gray color, and gray black on the reverse after 14 days at 28°C. Straight conidia [15.0 to 27.5 × 3.5 to 7.0 µm in size (average 18.2 × 6.1 µm) (n = 50)] were cylindrical, aseptate, hyaline, slippery surface, most with one tapering end and the other oval. Setae were black, 185-230 µm in length, with a thin tip and septate in the middle. Appressoria [6.5 to 7.3 × 7.8 to 9.2 µm in size (average 6.8 × 8.1 µm) (n = 15)] were black to dark brown, solitary, spherical with smooth wall. The fungal isolates were identified as Colletotrichum sansevieriae Nakamura (Nakamura et al. 2006), based on the morphological characteristics. To confirm the identification, the internal transcribed spacer (ITS) and calmodulin (CAL) regions of a representative isolate HWL-1016 were amplified by primers ITS1/ITS4 (White et al. 1990) and CMD5/CMD6 (Weir et al. 2012), respectively. The 549 bp ITS (MN922517) and 597 bp CAL (OM994078) sequences had respectively 100% and 99.30% identity with the sequences from holotype species of C. sansevieriae MAFF 239721 (no. NR_152313 and LC180125). Phylogenetic tree based on ITS and CAL sequences respectively or jointly constructed by PAUP4.0 (Swofford 2002) revealed that the fungus in this study clustered with C. sansevieriae isolates (NR_152313, KC790947, HQ433226, JF911349, MN386823). Pathogenicity test of isolate HWL1016 was evaluated on five 3- to 4-month-old potted S. trifasciata var. laurentii under greenhouse conditions (27±2 °C, 16-hr light/8-hr dark photoperiod, 80% relative humidity). Conidial suspension (1×106 conidia/mL) of the isolated fungus from PDA colonies cultured for 15 days and sterile distilled water (as control) were sprayed on pin-pricked surface-sterilized (70% alcohol) leaves of potted plants, respectively. Three replications (three plants) were done for each treatment, and the experiment was repeated twice. The inoculated plants were covered with plastic films for 2 days and obvious water-soaked wounds were observed on the sixth day. After 16 days, the symptoms of the inoculated plants were similar to those in the nursery, with disease incidence reached 100%, while controls remained symptomless. C. sansevieriae was subsequently reisolated from the symptomatic tissues. Anthracnose on S. trifasciata var. laurentii caused by C. sansevieriae has been reported in Australia, Iran, Japan, Malaysia (Kee et al. 2020), South Korea, USA (Talhinhas & Baroncelli 2021), India (Gautam et al. 2012) and Thailand (Li et al. 2020). To our knowledge, this is the first report of C. sansevieriae causing anthracnose on S. trifasciata var. laurentii in China. This study will contribute to guide effective management based on pathogen.

First Report of Epicoccum sorghinum Causing Leaf Spot on Paeonia suffruticosa in China.

Tree peony (Paeonia suffruticosa Andr.; Paeoniaceae) is highly valued in Chinese culture for their ornamental and medicinal benefits in anti-inflammation, anti-arrhythmia, activating the immune system and protecting the cardiovascular system (Zhai et al. 2020). In May from 2019 to 2021, leaf spot symptoms were observed on tree peony in an area of 0.8 hm2 in Bozhou, Anhui Province, China; with a disease incidence of 35%. Initially, black-brown spots (0.5-2.4 mm) appeared on the leaves, as the disease developed, the spots enlarged to form round, black lesions. Small pieces of tissue taken from the margins of lesions were surface-disinfected by 75% ethanol for 20 s followed by 0.1% mercuric chloride for 3 min, rinsed with distilled sterile water for three times, placed on potato dextrose agar (PDA) at 25 ºC for 7 days in the dark.Fifteen single spore isolates were obtained as described (Dong 2009). When cultured on PDA for 10 days, colonies were white, villose, then became gray-brown, with the reverse side becoming reddish-brown; Chlamydospores globose or irregular shaped, dark brown, unicellular or multicellular (4.3 to 12.2 × 13.1 to 33.7 µm) (n = 200). Pycnidia were black-brown, mostly spheroid, and 86 to 128 × 110 to 197 µm (n = 50); Conidia were hyaline, ellipsoidal, unicellular, aseptate, and 4.1 to 5.2 × 1.8 to 2.4 µm (n = 200) . The DNA of a representative isolate AF21-1-2 was extracted using the CTAB protocol (Doyle and Doyle 1987). The rDNA internal transcribed spacer (ITS), ß-tubulin (TUB) and 28s nrDNA (LSU) genes were amplified and sequenced using the primers ITS1/ITS4 (White et al. 1990), Bt2a/Bt2b (Glass et al. 1995), and LR5/LR0R (Vilgalys and Hester, 1990), respectively (OK485136, OK631973, and ON358331). BLASTn analysis showed that the ITS, TUB, and LSU sequences had 99% (497/501 bp), 98% (530/539 bp), and 99% (878/882 bp) identity with the Epicoccum sorghinum isolates ESCZO20 (MN944541), CZ01 (MT254851) and Dl16-338 (LN907481), respectively. Maximum likelihood phylogenetic tree revealed that AF21-1-2 clustered with E. sorghinum isolates. For pathogenicity test, leaves of 3-year-old healthy tree peony plant in the field were inoculated with 105 conidia/ml spore suspension (prepared with 30-day-old cultures on PDA), added with 0.1% (v/v) Tween-80. Ten surface-sterilized leaves per plant were sprayed with 30 ml suspension until runoff, a total of 3 plants were inoculated. Leaves sprayed with sterilized water serve as a negative control. Each plant was covered with a plastic bag to maintain high relative humidity at 15 to 23°C and was monitored daily for symptom development. Typical symptoms appeared on more than 80% of the leaves after 7 days of inoculation, while control leaves remained symptomless. Cultures isolated from inoculated leaves had the same morphological and molecular traits as those that were previously used to test Koch's postulates. Based on the morphological and molecular characteristics, the causal agent on tree peony was identified as E. sorghinum (Aveskamp et al. 2010). To our knowledge, this is the first report of E. sorghinum causing leaf spot on tree peony in China. The disease will cause serious economic loss for tree peony if it is not managed properly. This report may provide the basis for diagnosis and control of the disease.

Preparation of Fibroblast Suppressive Poly(ethylene glycol)-b-poly(l-phenylalanine)/Poly(ethylene glycol) Hydrogel and Its Application in Intrauterine Fibrosis Prevention.

Intrauterine adhesions (IUA) often occur as a result of trauma to the basal layer after curettage, postpartum hemorrhage, or surgical miscarriage. Endometrial fibrosis is the primary pathological feature of IUA. The characteristic features of IUA include excessive deposition and reorganization of the extracellular matrix, replacing the normal endometrium. To prevent uterine fibrosis after injury, we prepared and evaluated a type of fibroblast suppressive hydrogel. Poly(ethylene glycol)-b-poly(l-phenylalanine) (PEBP) copolymers were successfully synthesized by ring opening polymerization of l-Phenylalanine N-carboxyanhydride, initiated by methoxy-poly(ethylene glycol)-amine. Injectable PEBP/PEG hydrogels were subsequently formed through π-π accumulations between PEBP macromolecules and hydrogen bonds among PEBP, PEG, and H2O molecules. PEBP/PEG hydrogel could suppress the proliferation of fibroblasts due to the action of l-Phe, released sustainably from PEBP/PEG gels. Lastly, the in vivo preventive effect of PEBP/PEG hydrogel on fibrosis was evaluated in a rat uterine curettage model. It was found that PEBP/PEG hydrogel suppressed uterine fibrosis caused by curettage and promoted embryo implantation in injured uterine by regulating the expression and interactions of transforming growth factor beta 1 (TGF-ß1) and Muc-4. PEBP/PEG hydrogels have the potential for application in uterine adhesion prevention owing to their fibrosis preventive and pregnancy promotiing effects on uterine tissue after injury.

Urea-Doped ZnO Films as the Electron Transport Layer for High Efficiency Inverted Polymer Solar Cells.

In this paper, urea-doped ZnO (U-ZnO) is investigated as a modified electron transport layer (ETL) in inverted polymer solar cells (PSCs). Using a blend of Poly{4,8-bis[(2-ethylhexyl)oxy] benzo [1,2-b:4,5-b'] dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno [3,4-b] thiophene-4,6-diyl}(PTB7), and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as light absorber, a champion power conversion efficiency (PCE) of 9.15% for U-ZnO ETL based PSCs was obtained, which is 15% higher than that of the pure ZnO ETL based PSCs (7.76%). It was demonstrated that urea helps to passivate defects in ZnO ETL, resulting in enhanced exciton dissociation, suppressed charge recombination and efficient charge extraction efficiency. This work suggests that the utilization of the U-ZnO ETL offer promising potential for achieving highly efficient PSCs.

Solution-Processable ZnO/Carbon Quantum Dots Electron Extraction Layer for Highly Efficient Polymer Solar Cells.

In this work, we report the effort to develop high-efficiency inverted polymer solar cells (PSCs) by applying a solution-processable bilayer ZnO/carbon quantum dots (C-QDs) electron extraction layer (EEL). It is shown that the use of the bilayer EEL helps to suppress the exciton quenching by passivating the ZnO surface defects in the EEL, leading to an enhanced exciton dissociation, reduced charge recombination and more efficient charge extraction probability, and thereby achieving high power conversion efficiency (PCE). The inverted PSCs, based on the blend of poly{4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl} and [6,6]-phenyl C71-butyric acid methyl ester, possess a significant improvement in PCE of ∼9.64%, which is >27% higher than that of a control cell (∼7.59%). The use of a bilayer ZnO/C-QD EEL offers a promising approach for attaining high-efficiency inverted PSCs.

Synthesis and Properties of Dithiafulvenyl Functionalized Spiro[fluorene-9,9'-xanthene] Molecules.

Two spiroannulated molecular structures with dithiafulvenyl units functionalized at the 2,2',7,7'- (SFX-DTF1) and 2,3',6,'7- (SFX-DTF2) positions of a spiro[fluorene-9,9'-xanthene] core were synthesized. Studies revealed the hole mobility was significantly influenced by the dithiafulvenyl functionalized positions in the molecular structure. To explore their primary applications as hole-transporting materials in perovskite solar cells, SFX-DTF1-based devices exhibited a power conversion efficiency of 10.67% without the use of p-type dopants, yielding good air stability.

Induced hydrolytic enzymes of ectomycorrhizal fungi against pathogen Rhizoctonia solani.

Interactions between ectomycorrhizal fungi (Suillus laricinus, S. tomentosus, Amanita vaginata and Gomphidius viscidus) and the pathogen Rhizoctonia solani in co-culture were studied using both light and scanning electron microscopy. S. laricinus, S. tomentosus and A. vaginata inhibited the growth of the pathogen. Moreover, A. vaginata exhibited coiling around and penetration of the hyphae into R. solani was observed in the interaction zone. Furthermore, the production of chitinases, beta-1,3-glucanases and beta-glucosidases by these ectomycorrhizal fungi on colloidal chitin or cell walls of R. solani was evaluated: chitinases were not induced by colloidal chitin but all three enzymes were induced by R. solani cell walls. No correlation between inhibition rate and production of lytic enzymes was found.