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BACKGROUND: The push–pull strategy is considered as a promising eco‐friendly method for pest management. Plant volatile organic compounds (PVOCs) act as semiochemicals constitute the key factor in implementing this strategy. Benzyl alcohol and geraniol, as functional PVOCs, were reported to regulate insect behavior, showing the potential application in pest control. Using geraniol as lead, a geraniol derivative 5i with fine repellent activity was discovered in our previous work. In order to explore novel, eco‐friendly aphid control agents, a series of benzyl geranate derivatives was designed and synthesized using 5i as the lead and benzyl alcohol as the active fragment. RESULTS: Benzyl alcohol was firstly evaluated to have repellent activity to Acyrthosiphon pisum. Based on this repellent fragment, a series of novel benzyl geranate derivatives was rationally designed and synthesized using a scaffold‐hopping strategy. Among them, compound T9, with a binding affinity (Kd = 0.43 μm) and a substantial repellency of 64.7% against A. pisum, is the most promising compound. Molecule docking showed that hydrophobic and hydrogen‐bonding interactions substantially influenced the binding affinity of compounds with ApisOBP9. Additionally, T9 exhibited low‐toxicity to honeybees and ladybugs. CONCLUSION: Using a simple scaffold‐hopping strategy combined with active fragment benzyl alcohol, a new derivative T9, with high aphid‐repellency and low‐toxicity to nontarget organisms, can be considered as a novel potential eco‐friendly aphid control agent for sustainable agriculture. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

BACKGROUND: As one of the most abundant and destructive pests in agriculture, aphids cause significant damage to crops due to their sap‐taking and as virus vectors. Chemical insecticides are the most effective method to control aphids, but they bring insecticide resistance problems and harm nontarget organisms, especially bees, therefore the search for novel eco‐friendly aphid control agents with low bee toxicity is urgent. Insect kinins are a class of small neuropeptides that control important functions in insects. In our previous study, we found insect kinin analog IV‐3 has good aphicidal activity and the location of the aromatic ring on the side chain of Phe2 is the key to the formation of the β‐turn resulting in the biological activity of insect kinin analogs. However, there are few studies on insect kinin Phe2 substitution and modification, and its structure–activity relationship is still unclear. RESULTS: In this project, 44 insect kinin analogs with the Phe2 modification, replacing it with different natural or unnatural amino acids, were designed and synthesized based on the lead IV‐3 to explore the role of the Phe2 residues. Bioassays with soybean aphids of Aphis glycines indicated that nine analogs have better aphicidal activity than the lead IV‐3. In particular, compound L25 exhibits excellent aphicidal activity (LC50 = 0.0047 mmol L−1) and has low toxicity to bees. Furthermore, a reliable three‐dimensional quantitative structure–activity relationship (3D‐QSAR) was established to produce a helpful clue that introducing hydrophobic groups away from the backbone chain is beneficial to improve aphicidal activity. CONCLUSION: The residue Phe2 of insect kinin analogs is the key position and has a significant impact on the activity. L25 has a high toxicity for aphids, while a low toxicity to bees, and therefore can be considered as a lead compound to develop new biosafe aphid control agents. Finally, we provide a useful 3D‐QSAR model as theoretical guidance for further structural optimization. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

In view of the problem that the defoliation efficiency of the existing wormwood defoliation equipment is not high, the defoliation principle, the transmission mode and the force of the defoliation element of the defoliator are analyzed. The analysis results show that increasing the speed of the defoliation roller, the radius of the defoliation roller and the quality of the defoliation element can increase the striking force of the defoliation element and improve the defoliation efficiency. It is also possible to appropriately increase the length of the defoliation element to increase the striking range and improve the defoliation quality. Based on the analysis, the whole machine design of the defoliator was carried out and the speed of the conveying roller that achieved defoliation should be less than 400.9r/min. In order to avoid the critical speed of the defoliation roller and the conveying roller, the rollers were subjected to modal analysis using ANSYS software. To ensure the strength of the frame, the frame was statically analyzed. It is determined by the comparison experiment that the defoliation element should select the flexible defoliation element. The optimum speed of the defoliation roller was found to be around 1050r/min by the defoliation test. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of different designs of marginal preparation on stress distribution in the mandibular premolar restored with endocrown using three-dimensional finite element method., Methods: Four models with different designs of marginal preparation, including the flat margin, 90° shoulder, 135° shoulder and chamfer shoulder, were established to imitate mandibular first premolar restored with endocrown. A load of 100 N was applied to the intersection of the long axis and the occlusal surface, either parallel or with an angle of 45° to the long axis of the tooth. The maximum values of Von Mises stress and the stress distribution around the cervical region of the abutment and the endocrown with different designs of marginal preparation were analyzed., Results: The load parallel to the long axis of the tooth caused obvious stress concentration in the lingual portions of both the cervical region of the tooth tissue and the restoration. The stress distribution characteristics on the cervical region of the models with a flat margin and a 90° shoulder were more uniform than those in the models with a 135° shoulder and chamfer shoulder. Loading at 45° to the long axis caused stress concentration mainly on the buccal portion of the cervical region, and the model with a flat margin showed the most favorable stress distribution patterns with a greater maximum Von Mises stress under this circumstance than that with a parallel loading. Irrespective of the loading direction, the stress value was the lowest in the flat margin model, where the stress value in the cervical region of the endocrown was greater than that in the counterpart of the tooth tissue. The stress level on the enamel was higher than that on the dentin nearby in the flat margin model., Conclusions: From the stress distribution point of view, endocrowns with flat margin followed by a 90° shoulder are recommended.

Unlabelled: [ABSTRACT], Objective: To determine the value of low dose spiral CT scanning in diagnosing impacted teeth of children and adolescents., Methods: A total of 153 children and adolescents with confirmed impacted teeth in West China Second University Hospital, Sichuan University were enrolled in this study. They were divided into 5 groups according to the different spiral CT scan parameters (tube current time product, scanning thickness and collimation value): Group A (n=30, 330 mAs, 6 X 0. 75 mm and 3. 0 mm), Group B (n=30, 140 mAs, 6 X 0. 75 mm and 3. 0 mm), Group C (n=30, 80 mAs, 6 X 0. 75 mm and 3. 0 mm), Group D (n=31, 80 mAs, 6 X 1. 50 mm and 5. 0 mm), and Group E (n=32, 50 mAs, 6 X 1. 50 mm and 5. 0 mm). There were no significant differences in general clinical features (P>0. 05) among the participants of the five groups. The phantoms were used to measure spatial resolution and contrast resolution of the scan images. Dose length product (DLP) was recorded during CT scanning for calculating effective dose (ED) of exposure. The quality of images was evaluated using a list of quality scoring criteria., Results: (1) Under 330, 140, 80, 80 and 50 mAs, the images had a spatial resolution of 1.0 mm, with contrast resolution of 2. 0, 3. 0, 4. 5, 4. 5 and 6. 0 mm, respectively. (2) Significant differences in ED values were found among the five groups (F=1 064. 119, P=0. 000) and between every two of those groups (P<0. 05). Group E had the lowest ED (0. 19 mSv), 86. 52%, 67. 24%, 45. 71%, and 38. 71% lower than that in Group A, B, C and D, respectively (P<0. 05). (3) All of the five groups obtained an image quality score above 3, and no statistical differences appeared among the 5 groupl (F=1. 978, P>0. 05). The diagnostic results of the spiral CT were consistent with those of orthodontic surgery., Conclusion: Low dose spiral CT scanning can meet the image quality requirements for diagnosing impacted teeth, minimizing radiation exposure effectively.

Objective: To explore the morphology, proliferative activity and adhesion of adipose-derived stem cells (ASC) seeded in the polylactic-co-glycolic acid (PLGA) scaffold, and to provide experimental data for fabricating tissue engineered tympanic membrane repairment materials., Methods: Wistar rats were selected, and the ASC were isolated and co-cultured with the PLGA scaffold. The morphology and proliferative activity of ASC in the scaffold were examined by immunofluorescence of Vimentin and Ki67 respectively. All the immunofluorescence signals were analyzed by a confocal laser scan microscopy system FLUOVIEW FV1000. The adhesion of ASC to the PLGA scalfold was determined by scanning electron microscopy., Results: Immunofluorescence of vimentin showed rats ASC displayed normal morphology and grew orderly in the PLGA scalfold. Immunofluorescence of Ki67 showed the normal active proliferation of ASC in the scaffolds. The Ki67 mean positive index (x(-) ± s) of the ASC in the scalfold was (8.21 ± 1.76)%, while in control group (cultured without PLGA scalfold) was (9.06 ± 1.95)%. There was no statistic significance between the two groups (t = 1.03, P = 0.30). Scanning electron microscopy demonstrated ASC adhered well to the PLGA scalfold, the pseudopodia of ASC could also be observed and the proliferative cell conjunction was tight., Conclusion: ASC has good biocompatible to the PLGA scaffold and could normally adhere and proliferate in PLGA scaffold.

Objective: To prepare the tissue-engineering ossicle prosthesis which contained controlled release BMP-2 and implant into the acoustic bulla of guinea-pig, and observed the osteogenesis of the prosthesis in the bulla and the effect of the prosthesis on the cochlea., Methods: The acellular bony microtubule filled with collagen containing BMP-2 as tissue-engineering prosthesis was implanted into the acoustic bulla of the guinea-pig through the retroauricular approach. The prosthesis without BMP-2 was implanted into the contralateral bulla as control. ABR of the animals was checked after surgery at different time to observe the variation of the hearing threshold. After 3 months, the osteogenesis of the prosthesis and its effect on the structure of bulla, cochlea and hair cells was observed by histological technique and silver nitrate staining method., Results: The animals were recovered soon after surgery. The hearing threshold of the animals [(15.5 +/- 2.8) dB SPL] were increased slightly just after the surgery [(28.3 +/- 4.8) dB SPL, P<0.05], and come back completely after 3 month [(16.1 +/- 4.0) dB, P>0.05]. The prosthesis was covered with mucosa finally while the bulla and cochlea were normal in shape. The osteogenesis was occurred at the inner side of the acellular bony tube. There wasn't any abnormal hyperplasia of bone in the bulla and cochlea. The articulation between the stapes and oval window wasn't merged. The shape of the hair cells were normal and there wasn't obvious deletion of the hair cells compared with control group., Conclusions: The tissue-engineering ossicle prosthesis contained controlled release BMP-2 can induce osteogenesis in the bulla of the animals. This kind of material doesn't affect the shape of the bulla and the hearing threshold of the cochlea, moreover, they doesn't induce the abnormal hyperplasia of bone in the bulla and might be used to reconstruct the defects of ossicles.

Objective: To investigate the effects of reconstruction of maxillary sinus lateral bone wall and mucosa defect with collagen sponge and acellular cancellous bone combined with bone morphogenetic protein (BMP)-2 in situ. We observed the effect of the reparation and the BMP-2 induced osteogenesis., Methods: Ten New Zealand white rabbits underwent removal of part of unilateral maxillary sinus lateral bone wall with mucosa, and then divided into 2 equal groups: experimental group and control group. Acellular porcine cancellous vertebral bone was obtained, combined with BMP-2, trimmed to suit the defect, and put into the defect of the experimental group with collagen sponge soaked in venous blood, fixed by protein glue. Same porcine cancellous vertebral bone without BMP-2 was used in the control group. After 3 months the rabbits were killed to observe the osteogenesis of the defects., Results: The rabbits recovered soon after surgery. The implanted acellular cancellous bones were banded tightly with the bones around the defects, the medial surfaces of the materials were covered with mucosa, and new bone tissue entered into the pores of the complex BMP-2 materials. In the control group, only fibrillar connective tissue was filled in the pores., Conclusion: BMP-2 can induce osteogenesis, and collagen sponge serves to support the mucosal regeneration. Collagen sponge and acellular cancellous bone combined with BMP-2 can be used to repair the defects of the maxillary sinus bone wall and mucosa.

Objective: To make ossicular prosthesis using little columnar acellular cancellous bone combined with bone morphogenetic protein 2 (BMP-2) and implant into rabbits' acoustic vesicle to observe the osteogenesis in situ., Methods: To prepare the acellular cancellous bone combined with BMP-2 as ossicular prosthesis, the same material without BMP-2 were used in the control group. By retroauricular approach, a hole was made in the posterolateral bone wall of the acoustic vesicle and the prepared materials was implanted. After 3 month, the osteogenesis of the prosthesis with macroscopical anatomy and pathology were observed., Results: The rabbits recovered soon after surgery, the implanted acellular cancellous bones were banded tightly with the bone of the acoustic vesicle bone wall. The surface of all materials was covered with mucosa while osteogenesis was found in the material with BMP-2., Conclusion: The acellular cancellous bone with BMP-2 could induce osteogenesis in acoustic vesicle, so this material might be use to reconstruct the defects of ossicular chain.