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1.
Org Lett ; 26(36): 7565-7570, 2024 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-39230034

RESUMEN

Less steric ketones exhibited low stereoselectivity toward M5 due to their difficulty in restricting the free rotation of the imine intermediate. An engineered enantio-complementary imine reductase from M5 was obtained with catalytic activity. We identified four key residues that play essential roles in controlling stereoselectivity. Two mutants, I149Y-W234L (up to 99%S ee) and L200M-F260M (up to 99%R ee), were achieved, showing excellent stereoselectivity toward the tested substrates, offering valuable biocatalysts for synthesizing alkylated amphetamines.


Asunto(s)
Anfetaminas , Iminas , Oxidorreductasas , Estructura Molecular , Estereoisomerismo , Iminas/química , Oxidorreductasas/metabolismo , Oxidorreductasas/química , Anfetaminas/química , Anfetaminas/síntesis química , Alquilación , Catálisis , Biocatálisis
2.
Front Med (Lausanne) ; 11: 1436828, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39247638

RESUMEN

Objectives: Wilson's disease is an autosomal recessive disorder related to copper metabolism which mostly patients occurs in adolescents, fertility has become a problem that WD needs to face. Methods: A 21 years retrospective follow up study was conducted and a total of 220 female patients were included to identify patients with outcomes of pregnancy. Results: Untreated female patients with WD had a spontaneous abortion rate of 44%. During the study period, 146 female patients with WD from multicenter, 75 patients (51.4%) had successful outcomes of pregnancy. Notably, urinary copper levels below 616 µg/24 h were strongly associated with successful pregnancy. The nomogram built on these variables were age, urinary copper, haemoglobin and Child-Pugh classification, internally validated and showed good performance. Conclusion: The spontaneous abortion rate was 44% in untreated females with WD and developed a four-variable risk prediction model to accurately predict the likelihood of a successful pregnancy.

3.
Clin Lab ; 70(9)2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-39257108

RESUMEN

BACKGROUND: There have been only few reports on Rhupus syndrome with severe visceral involvement. Moreover, there was little consensus regarding its treatment. Belimumab is one of the options for treating this disease. For patients with clinical symptoms and elevated levels of anti CCP antibodies and anti-double stranded DNA antibodies, and it suggests Rhupus syndrome. After effective treatment, the decrease in levels of anti CCP antibodies and anti-double stranded DNA (ds-DNA) antibodies can effectively delay the progression of the disease and protect target organs. METHODS: We used a chemiluminescence instrument, (Yahuilong; Shenzhen, China), to measure the changes in CCP and dsDNA before and after treatment. RESULTS: Prior to treatment, the patient presented with symptoms of rheumatoid arthritis and systemic lupus erythematosus. Her laboratory tests showed dsDNA (214 IU/mL) and CCP level of ˃ 3,000 U/mL. After treatment with belimumab, the clinical symptoms were significantly relieved, and the patient's CCP IgG level decreased to 263.5 U/mL. A blood test found that her anti-dsDNA was negative. CONCLUSIONS: CCP and dsDNA can serve as indicators for the diagnosis and treatment of Rhupus syndrome.


Asunto(s)
Anticuerpos Antinucleares , Anticuerpos Monoclonales Humanizados , ADN , Humanos , Femenino , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Antinucleares/sangre , Anticuerpos Antinucleares/inmunología , ADN/inmunología , Lupus Eritematoso Sistémico/diagnóstico , Lupus Eritematoso Sistémico/tratamiento farmacológico , Lupus Eritematoso Sistémico/inmunología , Lupus Eritematoso Sistémico/sangre , Persona de Mediana Edad , Artritis Reumatoide/diagnóstico , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/inmunología , Artritis Reumatoide/sangre , Inmunosupresores/uso terapéutico , Resultado del Tratamiento , Autoanticuerpos/sangre , Autoanticuerpos/inmunología , Adulto , Biomarcadores/sangre
4.
Nat Commun ; 15(1): 7682, 2024 Sep 03.
Artículo en Inglés | MEDLINE | ID: mdl-39227380

RESUMEN

The inversion of substrate size specificity is an evolutionary roadblock for proteins. The Duf4243 dioxygenases GedK and BTG13 are known to catalyze the aromatic cleavage of bulky tricyclic hydroquinone. In this study, we discover a Duf4243 dioxygenase PaD that favors small monocyclic hydroquinones from the penicillic-acid biosynthetic pathway. Sequence alignments between PaD and GedK and BTG13 suggest PaD has three additional motifs, namely motifs 1-3, distributed at different positions in the protein sequence. X-ray crystal structures of PaD with the substrate at high resolution show motifs 1-3 determine three loops (loops 1-3). Most intriguing, loops 1-3 stack together at the top of the pocket, creating a lid-like tertiary structure with a narrow channel and a clearly constricted opening. This drastically changes the substrate specificity by determining the entry and binding of much smaller substrates. Further genome mining suggests Duf4243 dioxygenases with motifs 1-3 belong to an evolutionary branch that is extensively involved in the biosynthesis of natural products and has the ability to degrade diverse monocyclic hydroquinone pollutants. This study showcases how natural enzymes alter the substrate specificity fundamentally by incorporating new small motifs, with a fixed overall scaffold-architecture. It will also offer a theoretical foundation for the engineering of substrate specificity in enzymes and act as a guide for the identification of aromatic dioxygenases with distinct substrate specificities.


Asunto(s)
Secuencias de Aminoácidos , Dioxigenasas , Especificidad por Sustrato , Dioxigenasas/metabolismo , Dioxigenasas/genética , Dioxigenasas/química , Cristalografía por Rayos X , Hidroquinonas/metabolismo , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/química , Secuencia de Aminoácidos , Modelos Moleculares , Alineación de Secuencia
5.
Chem Biodivers ; : e202401218, 2024 Sep 14.
Artículo en Inglés | MEDLINE | ID: mdl-39275987

RESUMEN

In this research, the essential oils (EOs) from different parts of Ocimum gratissimum var. suave were chemically characterized and evaluated for insecticidal activity, especially against two common storage pests of Chinese herbal medicines: Tribolium castaneum and Liposcelis bostrychophila. Ocimum gratissimum is a plant with several medicinal values in traditional Chinese medicine. In the study, EOs were successfully extracted from inflorescences (OGI) and stem-leaf (OGLS) parts of O. gratissimum by steam distillation and 16 compounds were identified by gas chromatography-mass spectrometry (GC-MS), of which eugenol was the major constituent in both extracts. In fumigation toxicity tests against both pests, the EOs showed limited toxicity against T. castaneum but showed better toxicity against L. bostrychophila. Contact toxicity tests showed that OGLS had better insecticidal potential than OGI, while the insecticidal effect of eugenol sometimes exceeded that of EOs. In addition, repellency experiments showed that O. gratissimum EOs repelled the pests to varying degrees, with the effect being influenced by concentration and exposure time. The results suggest that O. gratissimum EOs could be a promising alternative to synthetic insecticides for sustainable utilization.

6.
Chem Biodivers ; : e202400818, 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39110524

RESUMEN

Insect infestations continually endanger stored goods, underscoring the significance of discovering eco-friendly insecticides for pest management. Essential oils (EOs) from different parts of Toddalia asiatica (leaf, fruit and branch) were extracted by hydrodistillation and analyzed by GC-MS. Carvene, p-cymene and muurolene are the principal compounds of T. asiatica leaf (TAL), T. asiatica fruit (TAF) and T. asiatica branch (TAB) EO respectively. Our work aimed to assess the contact toxicity and repellent effects of EOs on two storage pests, Tribolium castaneum and Lasioderma serricorne. All tested EOs exhibited obvious contact toxicity, especially, TAL EO against T. castaneum (33.48 µg/adult) and TAF EO against L. serricorne (16.42 µg/adult). Repellency tests revealed that TAL and TAF EOs, at a concentration of 78.63 nL/cm2, achieved nearing 100% efficiency against T. castaneum. These results suggest that EOs of T. asiatica could be used as effective botanical insecticides for managing stored-product insects.

7.
J Oleo Sci ; 73(5): 761-772, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38692898

RESUMEN

Volatile secondary metabolites of plants interact with environments heavily. In this work, characteristic components of Michelia yunnanensis essential oils (EOs) were isolated, purified and identified by column chromatography, GC-MS and NMR. Leaves of M. yunnanensis were collected monthly and extracted for EOs to investigate chemical and insecticidal activity variations as well as potential influencing environments. Different organs were employed to reveal distribution strategies of characteristic components. Results of insecticidal activities showed that all EOs samples exerted stronger contact activity to Lasioderma serricorne, but repellent effect was more efficient on Tribolium castaneum. One oxygenated sesquiterpene was isolated from EOs, basically it could be confirmed as (+)-cyclocolorenone (1). It exerted contact toxicity to L. serricorne (LD 50 = 28.8 µg/adult). Chemical analysis showed that M. yunnanensis leaves in reproductive period would produce and accumulate more 1 than in vegetative period. Moreover, reproductive organs (flowers and fruits) contained more 1 than vegetative organs (leaves and twigs). Partial correlation analysis indicated that temperature-related elements positively correlated with the relative content of 1.


Asunto(s)
Insecticidas , Aceites Volátiles , Hojas de la Planta , Tribolium , Animales , Insecticidas/aislamiento & purificación , Insecticidas/análisis , Hojas de la Planta/química , Aceites Volátiles/farmacología , Aceites Volátiles/química , Aceites Volátiles/aislamiento & purificación , Tribolium/efectos de los fármacos , Sesquiterpenos/aislamiento & purificación , Sesquiterpenos/análisis , Repelentes de Insectos/análisis , Repelentes de Insectos/aislamiento & purificación , Repelentes de Insectos/farmacología , Temperatura
8.
Appl Microbiol Biotechnol ; 108(1): 323, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38713233

RESUMEN

Ergot alkaloids (EAs) are a diverse group of indole alkaloids known for their complex structures, significant pharmacological effects, and toxicity to plants. The biosynthesis of these compounds begins with chanoclavine-I aldehyde (CC aldehyde, 2), an important intermediate produced by the enzyme EasDaf or its counterpart FgaDH from chanoclavine-I (CC, 1). However, how CC aldehyde 2 is converted to chanoclavine-I acid (CC acid, 3), first isolated from Ipomoea violacea several decades ago, is still unclear. In this study, we provide in vitro biochemical evidence showing that EasDaf not only converts CC 1 to CC aldehyde 2 but also directly transforms CC 1 into CC acid 3 through two sequential oxidations. Molecular docking and site-directed mutagenesis experiments confirmed the crucial role of two amino acids, Y166 and S153, within the active site, which suggests that Y166 acts as a general base for hydride transfer, while S153 facilitates proton transfer, thereby increasing the acidity of the reaction. KEY POINTS: • EAs possess complicated skeletons and are widely used in several clinical diseases • EasDaf belongs to the short-chain dehydrogenases/reductases (SDRs) and converted CC or CC aldehyde to CC acid • The catalytic mechanism of EasDaf for dehydrogenation was analyzed by molecular docking and site mutations.


Asunto(s)
Aldehídos , Alcaloides de Claviceps , Aldehídos/metabolismo , Aldehídos/química , Dominio Catalítico , Alcaloides de Claviceps/biosíntesis , Alcaloides de Claviceps/química , Alcaloides de Claviceps/metabolismo , Simulación del Acoplamiento Molecular , Mutagénesis Sitio-Dirigida , Oxidación-Reducción , Oxidorreductasas/metabolismo , Oxidorreductasas/genética , Oxidorreductasas/química
9.
J Am Chem Soc ; 2024 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-38602511

RESUMEN

Meroterpenoid clavilactones feature a unique benzo-fused ten-membered carbocyclic ring unit with an α,ß-epoxy-γ-lactone moiety, forming an intriguing 10/5/3 tricyclic nested skeleton. These compounds are good inhibitors of the tyrosine kinase, attracting a lot of chemical synthesis studies. However, the natural enzymes involved in the formation of the 10/5/3 tricyclic nested skeleton remain unexplored. Here, we identified a gene cluster responsible for the biosynthesis of clavilactone A in the basidiomycetous fungus Clitocybe clavipes. We showed that a key cytochrome P450 monooxygenase ClaR catalyzes the diradical coupling reaction between the intramolecular hydroquinone and allyl moieties to form the benzo-fused ten-membered carbocyclic ring unit, followed by the P450 ClaT that exquisitely and stereoselectively assembles the α,ß-epoxy-γ-lactone moiety in clavilactone biosynthesis. ClaR unprecedentedly acts as a macrocyclase to catalyze the oxidative cyclization of the isopentenyl to the nonterpenoid moieties to form the benzo-fused macrocycle, and a multifunctional P450 ClaT catalyzes a ten-electron oxidation to accomplish the biosynthesis of the 10/5/3 tricyclic nested skeleton in clavilactones. Our findings establish the foundation for the efficient production of clavilactones using synthetic biology approaches and provide the mechanistic insights into the macrocycle formation in the biosynthesis of fungal meroterpenoids.

10.
Chem Biodivers ; 21(4): e202301711, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38372187

RESUMEN

Stored products are constantly infested by insects, so finding eco-friendly bioinsecticides for insect management is important. The work aimed to assess the insecticidal and repellent activity of essential oil (EO) from Hedychium glabrum S. Q. Tong, Hedychium coronarium Koen., and Hedychium yunnanense Gagnep. against Tribolium castaneum, Lasioderma serricorne, and Liposcelis bostrychophila. Results showed that 88 chemical components were identified in the extracted Hedychium EOs, indicating that they exhibited diversity in components. According to principal component analysis (PCA), the composition of the EO from the H. yunnanense stem and leaf (EOHYSL) was significantly different from other EOs due to the different organs and species. The biological activity also varied continuously with plant species and organs. Only the EO of H. yunnanense (EOHY) showed strong fumigant toxicity. While in the contact tests, EOHGR showed the strongest toxicity effect on L. bostrychophila, with a LC50 value of 71.76 µg/cm2, which was closest to the positive control (Pyrethrin). All EOs had remarkable repellent activities against the three target insects, and repellency increased with concentration. According to the results of the comprehensive score, EOHY had the highest potential, which ranged from 0.7999 to 0.8689. Thus, Hedychium EOs possess potential biorational traits to be biological insecticides.


Asunto(s)
Escarabajos , Repelentes de Insectos , Insecticidas , Aceites Volátiles , Tribolium , Zingiberaceae , Animales , Aceites Volátiles/toxicidad , Aceites Volátiles/química , Insectos , Insecticidas/química , Repelentes de Insectos/farmacología , Repelentes de Insectos/química
11.
J Food Prot ; 87(1): 100205, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38065366

RESUMEN

Blumea balsamifera (L.) DC. (Asteraceae), also known as sambong, is a perennial herb used in China for medicinal purposes. The essential oil (EO) of B. balsamifera was extracted by hydrodistillation. Thirty chemical components of the EO were analyzed by gas chromatography-mass spectrometry (GC-MS) and GC, accounting for 88.0% (w/w) of the total oil. The EO of B. balsamifera was mainly composed of monoterpenes and sesquiterpenes, in which borneol (23.3%), ß-caryophyllene (20.9%) and camphor (11.8%) were the major components. The insecticidal activities of the EO and its three main compounds against Tribolium castaneum, Lasioderma serricorne and Sitophilus oryzae were evaluated. The results of bioassays displayed that the EO of B. balsamifera did not have fumigant toxicity to the three target insects, but exhibited significant contact activity against L. serricorne (LD50 = 12.4 µg/adult) and S. oryzae (LD50 = 44.4 µg/adult). Meanwhile, the EO showed a notable repellent effect on T. castaneum at all testing concentrations and a general repellent effect on S. oryzae at high concentrations (78.63 nL/cm2). ß-Caryophyllene showed the best performance in the contact toxicity bioassays against the three insects. The results indicated that B. balsamifera has the potential to be used as a source of botanical insecticides for the control of stored-product insects.


Asunto(s)
Asteraceae , Escarabajos , Insecticidas , Aceites Volátiles , Sesquiterpenos Policíclicos , Gorgojos , Animales , Aceites Volátiles/farmacología , Aceites Volátiles/química , Insecticidas/farmacología
12.
Environ Sci Pollut Res Int ; 30(59): 124416-124424, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37996575

RESUMEN

Chemical composition of the essential oil from Kochia scoparia (L.) Schrad. (syn. Bassia scoparia (L.) A. J. Scott) was analyzed in quality and quantity by GC-MS and GC-FID. Repellent activities of the essential oil from K. scoparia (KSEO) were evaluated against two common species of stored-product insects Tribolium castaneum Herbst and Liposcelis bostrychophila Badonnel. Results indicated that KSEO mainly consisted of eugenol, ß-caryophyllene, and α-humulene, accounting for 75.6%, 8.2%, and 1.4% of the total oil, respectively. KSEO and the three major components were repellent to T. castaneum and L. bostrychophila adults. Notably, KSEO exerted significant effects, comparable to the positive control DEET at 2 and 4 h post-exposure. Eugenol at 63.17-2.53 nL/cm2 exhibited high percentage repellency ranging from 96 to 70% against L. bostrychophila during 4-h exposure. To gain further insights into the repellent activity, molecular docking simulation was performed with eugenol as the ligand and an odorant binding protein TcOBPC12 (gene: TcOBP10B) from the model insect T. castaneum as the receptor. Docking calculation results revealed that TcOBPC12 had binding affinity to eugenol (△G = - 4.52 kcal/mol) along with a hydrogen bond of 0.18 nm (1.8 Å) long forming between them, which could be an important target protein associated with identifying volatile repellent molecules. This work highlights the promising potential of KSEO as a botanical repellent for controlling stored-product insects.


Asunto(s)
Bassia scoparia , Repelentes de Insectos , Insecticidas , Aceites Volátiles , Tribolium , Animales , Aceites Volátiles/farmacología , Aceites Volátiles/química , Eugenol/farmacología , Simulación del Acoplamiento Molecular , Insectos , Repelentes de Insectos/farmacología , Repelentes de Insectos/química , Insecticidas/química
13.
J Chem Phys ; 159(16)2023 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-37902609

RESUMEN

Researching ultrafast dynamics and creating coherent light sources will both benefit significantly from the establishment of polarization control in high-order harmonic generation (HHG). By employing the time-dependent density functional theory method, we investigate HHG of carbonyl sulfide molecules using a combination of a linear polarized infrared (IR) laser and a weaker orthogonal Terahertz (THz) field. Our findings show that by adjusting the amplitude of the THz field, the movement scale of electrons in the THz direction can be tuned, thereby one can control the harmonic intensity in the IR laser direction. This method allows for the creation of near-circularly polarized attosecond pulses. Furthermore, the ellipticity of the attosecond pulse may be changed by modifying the carrier-envelope phase of the IR laser pulse.

14.
Environ Sci Pollut Res Int ; 30(51): 110841-110850, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37794224

RESUMEN

The adverse effects of relying solely on synthetic pesticides have become increasingly evident, leading many countries to explore alternatives sourced from plant-based green economies. Essential oil (EO) from stems and leaves of Adenosma buchneroides Bonati (A. buchneroides) was distilled by using hydrodistillation and subjected to gas chromatography-mass spectrometry (GC-MS) for component identification. Subsequently, EO as well as its main constituents (thymol and p-cymene) were tested for their insecticidal activity against the red flour beetle (Tribolium castaneum), the cigarette beetle (Lasioderma serricorne), and the booklouse (Liposcelis bostrychophila). The joint action of thymol and p-cymene produced an additive or synergistic effect. A. buchneroides essential oil (BHO) and the fixed ratio of the main compounds, thymol, and p-cymene both showed significant toxic activity against the target pests. This toxic effect is not simply the sum of individual effects, as it is influenced by various factors such as insect species and mode of action. These findings imply that the BHO and its phytoconstituents possess great potential to develop plant-derived biopesticides that will be safe for humans and the environment.


Asunto(s)
Escarabajos , Repelentes de Insectos , Insecticidas , Aceites Volátiles , Tribolium , Animales , Humanos , Aceites Volátiles/química , Timol/farmacología , Repelentes de Insectos/farmacología , Insectos , Insecticidas/química
15.
Chem Biodivers ; 20(12): e202301206, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37840218

RESUMEN

Storage is a crucial part during grain production for the massive spoilage caused by stored product insects. Essential oils (EOs) of plant origin have been highly recommended to combating insects which are biodegradable and safe mode of action. Hence, to make the fullest use of natural resources, essential oils of different parts from Piper yunnanense (the whole part, PYW; fruits, PYF; leaves, PYL) and Piper boehmeriifolium (leaves, PBL) were extracted by steam distillation method in the present study. Gas chromatography-mass spectrometry (GC-MS) characterization revealed bicyclogermacrene (PYW), γ-muurolene (PYF), δ-cadinene (PYL) and methyl 4,7,10,13,16,19-docosahexaenoate (PBL) as the principal compound of each essential oil. Sesquiterpene hydrocarbons were also recognized as the richest class accounting for 56.3 %-94.9 % of the total oil. Three storage pests, Tribolium castaneum, Lasioderma serricorne and Liposceis bostrychophila, were exposed to different concentrations of EOs to determine their insecticidal effects. All tested samples performed modest contact toxicity in contrast to a bioactive ingredient pyrethrin, among which the most substantial effects were observed in PYF EOs against T. castaneum (35.84 µg/adult), PBL EOs against L. serricorne (15.76 µg/adult) and PYW EOs against L. bostrychophila (57.70 µg/cm2 ). In terms of repellency tests, essential oils of PYF at 78.63 nL/cm2 demonstrated to have a remarkable repellence against T. castaneum at 2h and 4h post-exposure. The investigations indicate diverse variations in the chemical profiles and insecticidal efficacies of P. yunnanense and P. boehmeriifolium EOs, providing more experimental evidence for the use of the Piper plants.


Asunto(s)
Escarabajos , Repelentes de Insectos , Insecticidas , Aceites Volátiles , Piper , Tribolium , Animales , Aceites Volátiles/química , Insectos , Repelentes de Insectos/farmacología , Repelentes de Insectos/química , Insecticidas/química
16.
Chem Biodivers ; : e202300935, 2023 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-37715638

RESUMEN

Many synthetic pesticides were used to control a severe storage pest, booklouse (Liposcelis bostrychophila). However, considering the environmental impact, plant secondary metabolites were acceptable alternatives. An endemic plant, Magnolia laevifolia, has a significant and unique odour, so its essential oil (EO) could be an option for bio-pesticide development. This study extracted EOs from leaves, flowers, carpels and seeds of M. laevifolia. The common and major compound of EOs was isocapnell-9-en-8-one, which was present at 17.7 to 91.6 % in these four parts. We found no regular pattern in the composition of EO in terms of parts and collection time according to principal component analysis. The contact and repellent activities of EOs against the booklouse were then conducted. Leaves and flowers' EOs collected in the flowering stage had the best contact toxicity. The percent repellency values of the EOs from different parts of M. laevifolia reached above 80 % after 2 and 4 h exposure at 63.17 nL/cm2 , with the same levels as DEET (p<0.05). It was shown that parts of plants and collecting time could influence the insecticidal activities of M. laevifolia EOs against booklouse, but collecting time played a significant decisive role in the contact test.

17.
Materials (Basel) ; 16(17)2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37687716

RESUMEN

As a transfer member at the discontinuous place of vertical load, the deep beam has a complex stress mechanism and many influencing factors, such as compressive strength of concrete, shear span ratio, and reinforcement ratio. At the same time, the stress analysis principle of traditional shallow beams is no longer applicable to the design and calculation of deep-beam structure. The main purpose of this paper was to use the strut-and-tie model to analyze its stress mechanism, and to verify the applicability of the model. Nine high-strength concrete deep-beam specimens with longitudinal reinforcement with an anchor plate of the same size were tested by two-point concentrated loading method. The effects of shear span ratio (0.3, 0.6, and 0.9), longitudinal reinforcement ratio (0.67%, 1.05%, and 1.25%), horizontal reinforcement ratio (0.33%, 0.45%, and 0.50%), and stirrup reinforcement ratio (0.25%, 0.33%, and 0.50%) on the failure mode, deflection curve, characteristic load, crack width, steel bar, and concrete strain of the specimens were analyzed. The results showed that the failure mode of deep-beam specimens was diagonal compression failure. The normal section cracking load was about 15 to 20% of the ultimate load, and the inclined section cracking load was about 30~40% of the ultimate load. The shear span ratio increased from 0.3 to 0.9, and the bearing capacity decreased by 32.9%. When the longitudinal reinforcement ratio increased from 0.67% to 1.25%, the ultimate load increased by 42.6%. The shear span ratio and longitudinal reinforcement ratio have a significant effect on the bearing capacity of the high-strength concrete deep beams with longitudinal reinforcement with an anchor plate. The shear capacity of nine high-strength concrete deep-beam specimens with longitudinal reinforcement with an anchor plate was calculated by national standards, and the results were compared with the calculation results of the Tan-Tang model, the Tan-Cheng model, SSTM, and SSSTM. The analysis showed that the softened strut-and-tie model takes into account the softening effect of compressive concrete, and is a more accurate mechanical model, which can be applied to predict the shear capacity of high-strength concrete deep-beam members with longitudinal reinforcement with an anchor plate.

18.
Opt Express ; 31(19): 30171-30183, 2023 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-37710565

RESUMEN

The spectral features of high-order harmonic spectra can provide rich information for probing the structure and dynamics of molecules in intense laser fields. We theoretically study the high harmonic spectrum with the laser polarization direction perpendicular to the N2O molecule and find a minimum structure in the plateau region of the harmonic spectrum. Through analyzing the time-dependent survival probability of different electronic orbitals and the time-dependent wave packet evolution, it is found that this minimum position is caused by the harmonic interference of HOMO a, HOMO-1, and HOMO-3 a orbitals. Moreover, this interference minimum is discovered over a wide frequency range of 0.087 a.u. to 0.093 a.u., as well as a range of driving laser intensities with peak amplitudes between 0.056 a.u. and 0.059 a.u.. This study sheds light on the multi-electron effects and ultrafast dynamics of inner-shell electrons in intense laser pulses, which are crucial for understanding and controlling chemical reactions in molecules.

19.
Diagnostics (Basel) ; 13(15)2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37568923

RESUMEN

BACKGROUND: This study aimed to investigate the natural growth history of peripheral small-cell lung cancer (SCLC) using CT imaging. METHODS: A retrospective study was conducted on 27 patients with peripheral SCLC who underwent at least two CT scans. Two methods were used: Method 1 involved direct measurement of nodule dimensions using a calliper, while Method 2 involved tumour lesion segmentation and voxel volume calculation using the "py-radiomics" package in Python. Agreement between the two methods was assessed using the intraclass correlation coefficient (ICC). Volume doubling time (VDT) and growth rate (GR) were used as evaluation indices for SCLC growth, and growth distribution based on GR and volume measurements were depicted. We collected potential factors related to imaging VDT and performed a differential analysis. Patients were classified into slow-growing and fast-growing groups based on a VDT cut-off point of 60 days, and univariate analysis was used to identify factors influencing VDT. RESULTS: Median VDT calculated by the two methods were 61 days and 71 days, respectively, with strong agreement. All patients had continuously growing tumours, and none had tumours that decreased in size or remained unchanged. Eight patients showed possible growth patterns, with six possibly exhibiting exponential growth and two possibly showing Gompertzian growth. Tumours deeper in the lung grew faster than those adjacent to the pleura. CONCLUSIONS: Peripheral SCLC tumours grow rapidly and continuously without periods of nongrowth or regression. Tumours located deeper in the lung tend to grow faster, but further research is needed to confirm this finding.

20.
World J Clin Cases ; 11(21): 5108-5114, 2023 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-37583849

RESUMEN

BACKGROUND: Fibrobronchoscopy is a common adjunct tool that requires anesthesia and is widely used in the diagnosis and treatment of various respiratory diseases. However, current anesthesia methods, such as spray, nebulized inhalation, and cricothyroid membrane puncture, have their own advantages and disadvantages. Recently, studies have shown that bronchoscopic direct-view glottis anesthesia is a simple and inexpensive method that shortens the examination time and provides excellent anesthetic results. AIM: To evaluate the effectiveness of bronchoscopic direct vision glottis anesthesia for bronchoscopy. METHODS: The study included 100 patients who underwent bronchoscopy during thoracic surgery. A random number table method was used to divide the patients into control and observation groups (50 patients each). The control and observation groups were anesthetized using the nebulized inhalation and bronchoscopic direct vision glottis method, respectively. Hemodynamic indices [systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and oxygen saturation (SpO2) before (T1), 5 min after anesthesia (T2), and at the end of the operation (T3)] serum stress hormone indices [norepinephrine (NE), epinephrine (E), adrenocorticotropic hormone (ACTH), and cortisol (Cor) before and after treatment] were compared between the 2 groups. Adverse effects were also compared between the two groups. RESULTS: At T2 and T3, SBP, DBP, and HR were lower in the observation group than the control group, whereas SpO2 was higher than the control group [(119.05 ± 8.01) mmHg vs (127.05 ± 7.83) mmHg, (119.35 ± 6.66) mmHg vs (128.39 ± 6.56) mmHg, (84.68 ± 6.04) mmHg vs (92.42 ± 5.57) mmHg, (84.53 ± 4.97) mmHg compared to (92.57 ± 6.02) mmHg, (74.25 ± 5.18) beats/min compared to (88.32 ± 5.72) beats/min, (74.38 ± 5.31) beats/min compared to (88.42 ± 5.69) beats/min, (97.36 ± 2.21)% vs (94.35 ± 2.16)%, (97.42 ± 2.36)% vs (94.38 ± 2.69%], with statistically significant differences (all P < 0.05). After treatment, NE, E, ACTH, and Cor were significantly higher in both groups than before treatment, but were lower in the observation group than in the control group [(68.25 ± 8.87) ng/mL vs (93.35 ± 14.00) ng/mL, (53.59 ± 5.89) ng/mL vs (82.32 ± 10.70) ng/mL, (14.32 ± 1.58) pg/mL vs (20.35 ± 3.05) pg/mL, (227.35 ± 25.01) nmol/L vs (322.28 ± 45.12) nmol/L], with statistically significant differences (all P < 0.05). The incidence of adverse reactions was higher in the control group than in the observation group [12.00% (12/50) vs 6.00% (3/50)] (P < 0.05). CONCLUSION: The use of bronchoscopic direct vision glottis anesthesia method for bronchoscopy patients is beneficial for stabilizing hemodynamic indices during bronchoscopy and reducing the level of patient stress, with good safety and practicality.

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