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1.
J Adv Res ; 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38825317

RESUMO

INTRODUCTION: Rhizoctonia solani Kühn is a pathogen causing rice sheath blight (ShB). Ammonium transporter 1 (AMT1) promotes resistance of rice to ShB by activating ethylene signaling. However, how AMT1 activates ethylene signaling remains unclear. OBJECTIVE: In this study, the indeterminate domain 10 (IDD10)-NAC079 interaction model was used to investigate whether ethylene signaling is modulated downstream of ammonium signaling and modulates ammonium-mediated ShB resistance. METHODS: RT-qPCR assay was used to identify the relative expression levels of nitrogen and ethylene related genes. Yeast two-hybrid assays, Bimolecular fluorescence complementation (BiFC) and Co-immunoprecipitation (Co-IP) assay were conducted to verify the IDD10-NAC079-calcineurin B-like interacting protein kinase 31 (CIPK31) transcriptional complex. Yeast one-hybrid assay, Chromatin immunoprecipitation (ChIP) assay, and Electrophoretic mobility shift assay (EMSA) were used to verify whether ETR2 was activated by IDD10 and NAC079. Ethylene quantification assay was used to verify ethylene content in IDD10 transgenic plants. Genetic analysis is used to detect the response of IDD10, NAC079 and CIPK31 to ShB infestation. RESULTS: IDD10-NAC079 forms a transcription complex that activates ETR2 to inhibit the ethylene signaling pathway to negatively regulating ShB resistance. CIPK31 interacts and phosphorylates NAC079 to enhance its transcriptional activation activity. In addition, AMT1-mediated ammonium absorption and subsequent N assimilation inhibit the expression of IDD10 and CIPK31 to activate the ethylene signaling pathway, which positively regulates ShB resistance. CONCLUSION: The study identified the link between ammonium and ethylene signaling and improved the understanding of the rice resistance mechanism.

2.
Artigo em Inglês | MEDLINE | ID: mdl-38781497

RESUMO

BACKGROUND AND OBJECTIVES: Drug-coated balloons (DCBs) have exhibited promising results in coronary and peripheral artery diseases, but conclusive evidence is lacking in intracranial vasculature. We assessed the safety and efficacy of DCBs vs stent angioplasty for symptomatic intracranial atherosclerotic stenosis (sICAS) and initially identified patients who might have benefited most from DCB treatment. METHODS: A single-center, retrospective cohort study was conducted from June 2021 to May 2022 with 154 patients with sICAS divided into 2 treatment groups: a DCB group (with or without remedial stenting, n = 47) and a stent group (n = 107). The treatment outcomes were compared using 1:2 propensity score matching. The primary safety end point was perioperative stroke or mortality, and the primary efficacy end point was the rate of target vessel restenosis at 12 months. The degree of luminal change was analyzed as a subgroup, defined as the difference between the degree of stenosis at follow-up and immediately after intervention. RESULTS: One hundred eighteen patients were enrolled using propensity score matching, with 43 patients in the DCB group and 75 in the stent group. The incidence of perioperative adverse events was 2.3% in the DCB group and 8.0% in the stent group (P = .420). At a median follow-up of 12 months, the incidence of restenosis (11.9% [5/43] vs 28.0% [21/75], P = .045) and the median degree of stenosis (30% [20%, 44%] vs 30% [30%, 70%], P = .009, CI [0-0.01, 0.2]) were significantly lower in the DCB group than in the stent group. DCB angioplasty effectively prevented adverse events in the target vessel area and significantly reduced the degree of luminal change in the M1 segment of the middle cerebral artery (0 [0, 15%] vs 10% [0, 50%], P = .016). CONCLUSION: DCB angioplasty might be a safe and effective alternative to stent angioplasty to treat sICAS, particularly among patients with M1 segment of the middle cerebral artery stenosis.

3.
Fitoterapia ; 174: 105880, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38431026

RESUMO

An undescribed trichodenone derivative (1), two new diketopiperazines (3 and 4) along with a bisabolane analog (2) were isolated from Trichoderma hamatum b-3. The structures of the new findings were established through comprehensive analyses of spectral evidences in HRESIMS, 1D and 2D NMR, Marfey's analysis as well as comparisons of ECD. The absolute configuration of 2 was unambiguously confirmed by NMR, ECD calculation and Mo2(AcO)4 induced circular dichroism. Compounds 1-4 were tested for their fungicidal effects against eight crop pathogenic fungi, among which 1 showed 51% inhibition against Sclerotinia sclerotiorum at a concentration of 50 µg/mL.


Assuntos
Hypocreales , Trichoderma , Estrutura Molecular , Dicetopiperazinas/química , Trichoderma/química
4.
Commun Biol ; 7(1): 161, 2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38332111

RESUMO

Auxins and their analogs are widely used to promote root growth, flower and fruit development, and yield in crops. The action characteristics and application scope of various auxins are different. To overcome the limitations of existing auxins, expand the scope of applications, and reduce side effects, it is necessary to screen new auxin analogs. Here, we identified 3,4-dichlorophenylacetic acid (Dcaa) as having auxin-like activity and acting through the auxin signaling pathway in plants. At the physiological level, Dcaa promotes the elongation of oat coleoptile segments, the generation of adventitious roots, and the growth of crop roots. At the molecular level, Dcaa induces the expression of auxin-responsive genes and acts through auxin receptors. Molecular docking results showed that Dcaa can bind to auxin receptors, among which TIR1 has the highest binding activity. Application of Dcaa at the root tip of the DR5:GUS auxin-responsive reporter induces GUS expression in the root hair zone, which requires the PIN2 auxin efflux carrier. Dcaa also inhibits the endocytosis of PIN proteins like other auxins. These results provide a basis for the application of Dcaa in agricultural practices.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Ácidos Indolacéticos/farmacologia , Ácidos Indolacéticos/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Simulação de Acoplamento Molecular , Raízes de Plantas/metabolismo
5.
Oncol Rep ; 51(3)2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38240088

RESUMO

Bone marrow stromal cell antigen 2 (BST2) is a type II transmembrane protein that serves critical roles in antiretroviral defense in the innate immune response. In addition, it has been suggested that BST2 is highly expressed in various types of human cancer and high BST2 expression is related to different clinicopathological parameters in cancer. The molecular mechanism underlying BST2 as a potential tumor biomarker in human solid tumors has been reported on; however, to the best of our knowledge, there has been no review published on the molecular mechanism of BST2 in human solid tumors. The present review focuses on human BST2 expression, structure and functions; the molecular mechanisms of BST2 in breast cancer, hepatocellular carcinoma, gastrointestinal tumor and other solid tumors; the therapeutic potential of BST2; and the possibility of BST2 as a potential marker. BST2 is involved in cell membrane integrity and lipid raft formation, which can activate epidermal growth factor receptor signaling pathways, providing a potential mechanistic link between BST2 and tumorigenesis. Notably, BST2 may be considered a universal tumor biomarker and a potential therapeutical target.


Assuntos
Neoplasias da Mama , Neoplasias Hepáticas , Humanos , Feminino , Antígeno 2 do Estroma da Médula Óssea/metabolismo , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Neoplasias da Mama/patologia , Transdução de Sinais , Biomarcadores Tumorais/genética , Biologia
6.
Discov Oncol ; 14(1): 196, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37910338

RESUMO

Prostate cancer is the second incidence of malignant tumors in men worldwide. Its incidence and mortality are increasing year by year. Enhanced expression of Cav1 in prostate cancer has been linked to both proliferation and metastasis of cancer cells, influencing disease progression. Dysregulation of the Cav1 gene shows a notable association with prostate cancer. Nevertheless, there is no systematic review to report about molecular signal mechanism of Cav1 and drug treatment in prostate cancer. This article reviews the structure, physiological and pathological functions of Cav1, the pathogenic signaling pathways involved in prostate cancer, and the current drug treatment of prostate cancer. Cav1 mainly affects the occurrence of prostate cancer through AKT/mTOR, H-RAS/PLCε, CD147/MMPs and other pathways, as well as substance metabolism including lipid metabolism and aerobic glycolysis. Baicalein, simvastatin, triptolide and other drugs can effectively inhibit the growth of prostate cancer. As a biomarker of prostate cancer, Cav1 may provide a potential therapeutic target for the treatment of prostate cancer.

7.
Sensors (Basel) ; 23(10)2023 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-37430570

RESUMO

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.

8.
J Org Chem ; 88(14): 9769-9782, 2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37428133

RESUMO

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.

9.
Discov Oncol ; 14(1): 104, 2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37326913

RESUMO

Human endogenous retroviruses (HERVs) have evolved from exogenous retroviruses and account for approximately 8% of the human genome. A growing number of findings suggest that the abnormal expression of HERV genes is associated with schizophrenia, multiple sclerosis, endometriosis, breast cancer, bladder cancer and other diseases. HERV-W env (syncytin-1) is a membrane glycoprotein which plays an important role in placental development. It includes embryo implantation, fusion of syncytiotrophoblasts and of fertilized eggs, and immune response. The abnormal expression of syncytin-1 is related to placental development-related diseases such as preeclampsia, infertility, and intrauterine growth restriction, as well as tumors such as neuroblastoma, endometrial cancer, and endometriosis. This review mainly focused on the molecular interactions of syncytin-1 in placental development-related diseases and tumors, to explore whether syncytin-1 can be an emerging biological marker and potential therapeutic target.

10.
Opt Express ; 31(10): 16795-16811, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37157751

RESUMO

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.

11.
Technol Cancer Res Treat ; 22: 15330338231175733, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37246525

RESUMO

Human cancer statistics show that an increased incidence of urologic cancers such as bladder cancer, prostate cancer, and renal cell carcinoma. Due to the lack of early markers and effective therapeutic targets, their prognosis is poor. Fascin-1 is an actin-binding protein, which functions in the formation of cell protrusions by cross-linking with actin filaments. Studies have found that fascin-1 expression is elevated in most human cancers and is related to outcomes such as neoplasm metastasis, reduced survival, and increased aggressiveness. Fascin-1 has been considered as a potential therapeutic target for urologic cancers, but there is no comprehensive review to evaluate these studies. This review aimed to provide an enhanced literature review, outline, and summarize the mechanism of fascin-1 in urologic cancers and discuss the therapeutic potential of fascin-1 and the possibility of its use as a potential marker. We also focused on the correlation between the overexpression of fascin-1 and clinicopathological parameters. Mechanistically, fascin-1 is regulated by several regulators and signaling pathways (such as long noncoding RNA, microRNA, c-Jun N-terminal kinase, and extracellular regulated protein kinases). The overexpression of fascin-1 is related to clinicopathologic parameters such as pathological stage, bone or lymph node metastasis, and reduced disease-free survival. Several fascin-1 inhibitors (G2, NP-G2-044) have been evaluated in vitro and in preclinical models. The study proved the promising potential of fascin-1 as a newly developing biomarker and a potential therapeutic target that needs further investigation. The data also highlight the inadequacy of fascin-1 to serve as a novel biomarker for prostate cancer.


Assuntos
Biomarcadores Tumorais , Carcinoma de Células Renais , Proteínas de Transporte , Neoplasias Renais , Neoplasias da Próstata , Neoplasias da Bexiga Urinária , Biomarcadores Tumorais/metabolismo , Proteínas de Transporte/metabolismo , Neoplasias da Bexiga Urinária/tratamento farmacológico , Neoplasias da Bexiga Urinária/metabolismo , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Humanos , Masculino , Terapia de Alvo Molecular , Metástase Linfática
12.
Pest Manag Sci ; 79(9): 3133-3140, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37013803

RESUMO

BACKGROUND: Pesticides are indispensable in agriculture and can effectively improve the yields and quality of crops. Due to their weak water solubility, most pesticides need to be dissolved by adding solubilizing adjuvants. In this work, based on molecular recognition of the macrocyclic host, we developed a novel supramolecular adjuvant, called sulfonated azocalix[4]arene (SAC4A), which significantly improves the water solubility of pesticides. RESULTS: SAC4A presents multiple advantages, including high water solubility, strong binding affinity, universality, and simple preparation. SAC4A showed an average binding constant value of 1.66 × 105 M-1 for 25 pesticides. Phase solubility results indicated that SAC4A increased the water solubility of pesticides by 80-1310 times. The herbicidal, fungicidal, and insecticidal activities of supramolecular formulations were found to be superior to those of technical pesticides, and the herbicidal effects were even better than those of commercial formulations. CONCLUSION: Overall results revealed the potential of SAC4A to improve the solubility and effectiveness of pesticides, providing a new development idea for the application of adjuvants in agriculture. © 2023 Society of Chemical Industry.


Assuntos
Praguicidas , Praguicidas/química , Agricultura , Solubilidade , Água/química
13.
J Agric Food Chem ; 71(16): 6226-6235, 2023 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-37053087

RESUMO

Streptochlorin is a kind of indole alkaloid derived from marine microorganisms. It is a promising lead compound due to its potent bioactivity in preventing many phytopathogens, as shown in our previous study. To explore the potential applications of this natural product, a series of novel benzoxaborole-containing streptochlorin derivatives were designed and synthesized through a one-step and catalyst-free reaction in water at room temperature. All target compounds were first screened for their antifungal profiles in vitro against six common phytopathogenic fungi. The results of bioassay revealed that most of the designed compounds exhibited more significant antifungal activities against Botrytis cinrea, Gibberella zeae, Rhizoctorzia solani, Colletotrichum lagenarium, and alternaria leaf spot under the concentration of 50 µg/mL, and this is highlighted by compounds 4i and 5f, which demonstrated impressive antifungal effects against G. zeae and R. solani, with their corresponding EC50 values 0.2983 and 0.2657 µg/mL, which are obviously better than positive control flutriafol and boscalid (5.2606 and 1.2048 µg/mL, respectively). Scanning electron microscopy on the hyphae morphology showed that compound 5b might cause mycelial abnormalities of G. zeae. 3D-QSAR studies of CoMFA and CoMSIA were carried out on 29 target compounds with antifungal activity against B. cinrea. The analysis results indicated that introducing appropriate electronegative groups at the 5-position of benzoxaborole and the 4,5-positions of the indole ring could effectively improve the anti-B. cinrea activity. Moreover, compound 5b showed good antifungal activities in vivo against Phytophthora capsici. Molecular docking was further explored to ascertain the practical value of the active compound as a potential inhibitor of LeuRS. The abovementioned results indicate that the designed benzoxaborole-containing streptochlorin derivatives could be further studied as template molecules of novel antifungal agents.


Assuntos
Antifúngicos , Antifúngicos/química , Antifúngicos/farmacologia , Relação Quantitativa Estrutura-Atividade , Modelos Moleculares , Conformação Molecular , Simulação de Acoplamento Molecular
14.
Pest Manag Sci ; 79(6): 2220-2229, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36750400

RESUMO

BACKGROUND: To obtain new environmentally friendly fungicides, we used the natural product pimprinine as the lead compound, and designed and synthesized two series of ring-opening derivatives of pimprinine containing amide/thioamide. We then studied their antifungal activity against six common plant pathogenic fungi in vitro. RESULTS: Most of the target compounds have good antifungal activity against six important plant pathogenic fungi in vitro. At a concentration of 50 µg ml-1 , compound 3o showed prominent antifungal effects on Alternaria solani and Rhioctornia solani, with inhibition rates of 91.8% and 97.4%, and a 50% effective concentration (EC50 ) of 6.2255 and 0.6969 µg ml-1 respectively. The EC50 of compound 3o against Alternaria solani was significantly lower than that of boscalid (13.0380 µg ml-1 ) and flutriafol (11.9057 µg ml-1 ). In addition, compound 3o had good antifungal activity against Sclerotinia sclerotiorum, cucumber powdery mildew, cucumber Botrytis cinerea and Phytophthora capsici in vivo; the antifungal activity of compound 3o against cucumber Botrytis cinerea is 91.7%. At the same time, docking results for highly active compound 3o with the presumed target succinate dehydrogenase and the molecular docking prediction scores of all compounds further indicate its possible antifungal activity mechanism. CONCLUSION: The designed and optimized derivative 3o of ring-opening pimprinine has good antifungal activity and can be used as a new antifungal drug for further research. © 2023 Society of Chemical Industry.


Assuntos
Antifúngicos , Fungicidas Industriais , Oxazóis , Amidas/farmacologia , Antifúngicos/química , Botrytis , Fungicidas Industriais/química , Simulação de Acoplamento Molecular , Estrutura Molecular , Relação Estrutura-Atividade , Oxazóis/química
15.
Mar Drugs ; 21(2)2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36827144

RESUMO

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.


Assuntos
Antifúngicos , Fungicidas Industriais , Antifúngicos/farmacologia , Estrutura Molecular , Relação Estrutura-Atividade , Simulação de Acoplamento Molecular , Oxazóis/química , Fungicidas Industriais/farmacologia
16.
J Sep Sci ; 46(8): e2200883, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36820810

RESUMO

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.


Assuntos
Espectrometria de Massas , China , Análise Discriminante
17.
Pest Manag Sci ; 79(5): 1977-1986, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36661091

RESUMO

BACKGROUND: To study the effect of changing the piperidine ring of oxathiapiprolin on the fungicidal activity, we designed and synthesized novel piperazine thiazole derivatives containing oxime ether or oxime ester moieties, and studied their fungicidal activities against Phytophthora capsici in vitro. RESULTS: These derivatives showed moderate to good fungicidal activities against Phytophthora capsici, two oxime ether derivatives showed higher fungicidal activity in vitro than dimethomorph (EC50  = 0.1331 µg mL-1 ) and comparable to oxathiapiprolin (EC50  = 0.0042 µg mL-1 ). Oxime ester derivatives showed significantly reduced activities compared with oxime ether derivatives. Most of these derivatives showed broad-spectrum fungicidal activity against the other eight kinds of fungi. Moreover, four derivatives exhibited good antifungal activities in vivo against Phytophthora capsici, Pseudoperonospora cubensis, and Phytophthora infestans. The hyphae morphology study showed that compound 10d might cause mycelial abnormalities of Phytophthora capsici. CONCLUSION: The activity of 10b against Phytophthora infestans was better than that of mandipropamid, and compound 10d exhibited higher fungicidal activities against Pseudoperonospora cubensis and Phytophthora infestans than mandipropamid. These two derivatives emerged as promising candidates for antifungal drugs. © 2023 Society of Chemical Industry.


Assuntos
Fungicidas Industriais , Phytophthora infestans , Antifúngicos/química , Fungicidas Industriais/química , Tiazóis/farmacologia , Éter/farmacologia , Ésteres/farmacologia , Oximas/farmacologia , Éteres/farmacologia , Etil-Éteres/farmacologia , Piperazinas/farmacologia , Relação Estrutura-Atividade
18.
Opt Lett ; 48(1): 73-76, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36563372

RESUMO

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.

19.
Opt Express ; 30(25): 44769-44784, 2022 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-36522893

RESUMO

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.

20.
J Agric Food Chem ; 70(42): 13510-13517, 2022 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-36251501

RESUMO

An efficient synthesis method will allow a large number of tetramic acid analogues to be synthesized for property and potency optimization. In this study, a facile and efficient method was described for the synthesis of 3-acyltetramic acids. The synthesis was accomplished mainly via (1) mild intramolecular cyclization and (2) the formation of ß-ketoamides between nucleophiles and acyl Meldrum's acids. 3-Acyltetramic acid exhibited phytotoxicity against Echinochloa crusgalli and Portulaca oleracea. At a dosage of 750 g ha-1, 6k and 6a showed high herbicidal activity against E. crusgalli, Digitaria sanguinalis and P. oleracea, Amaranthus retroflexus, respectively. 6k inhibited the synthesis of endogenous abscisic acid, thus seedling germination and plant growth. The incorporation of various acyl Meldrum's acids and amino acid esters was applicable to the parallel synthesis of 3-acyltetramic acids. The mode of action and herbicidal activity indicate that 3-tetramic acid had good herbicidal performance and was a promising herbicide candidate. This study will provide a reference for novel herbicide development.


Assuntos
Echinochloa , Herbicidas , Herbicidas/química , Ácido Abscísico/farmacologia , Digitaria , Aminoácidos
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