Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 45
Filtrar
1.
BMC Anesthesiol ; 24(1): 222, 2024 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-38965472

RESUMO

BACKGROUND: Transfer to the ICU is common following non-cardiac surgeries, including radical colorectal cancer (CRC) resection. Understanding the judicious utilization of costly ICU medical resources and supportive postoperative care is crucial. This study aimed to construct and validate a nomogram for predicting the need for mandatory ICU admission immediately following radical CRC resection. METHODS: Retrospective analysis was conducted on data from 1003 patients who underwent radical or palliative surgery for CRC at Ningxia Medical University General Hospital from August 2020 to April 2022. Patients were randomly assigned to training and validation cohorts in a 7:3 ratio. Independent predictors were identified using the least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression in the training cohort to construct the nomogram. An online prediction tool was developed for clinical use. The nomogram's calibration and discriminative performance were assessed in both cohorts, and its clinical utility was evaluated through decision curve analysis (DCA). RESULTS: The final predictive model comprised age (P = 0.003, odds ratio [OR] 3.623, 95% confidence interval [CI] 1.535-8.551); nutritional risk screening 2002 (NRS2002) (P = 0.000, OR 6.129, 95% CI 2.920-12.863); serum albumin (ALB) (P = 0.013, OR 0.921, 95% CI 0.863-0.982); atrial fibrillation (P = 0.000, OR 20.017, 95% CI 4.191-95.609); chronic obstructive pulmonary disease (COPD) (P = 0.009, OR 8.151, 95% CI 1.674-39.676); forced expiratory volume in 1 s / Forced vital capacity (FEV1/FVC) (P = 0.040, OR 0.966, 95% CI 0.935-0.998); and surgical method (P = 0.024, OR 0.425, 95% CI 0.202-0.891). The area under the curve was 0.865, and the consistency index was 0.367. The Hosmer-Lemeshow test indicated excellent model fit (P = 0.367). The calibration curve closely approximated the ideal diagonal line. DCA showed a significant net benefit of the predictive model for postoperative ICU admission. CONCLUSION: Predictors of ICU admission following radical CRC resection include age, preoperative serum albumin level, nutritional risk screening, atrial fibrillation, COPD, FEV1/FVC, and surgical route. The predictive nomogram and online tool support clinical decision-making for postoperative ICU admission in patients undergoing radical CRC surgery. TRIAL REGISTRATION: Despite the retrospective nature of this study, we have proactively registered it with the Chinese Clinical Trial Registry. The registration number is ChiCTR2200062210, and the date of registration is 29/07/2022.


Assuntos
Neoplasias Colorretais , Unidades de Terapia Intensiva , Nomogramas , Humanos , Masculino , Feminino , Estudos Retrospectivos , Pessoa de Meia-Idade , Neoplasias Colorretais/cirurgia , Idoso , Medição de Risco/métodos , Complicações Pós-Operatórias/epidemiologia , Admissão do Paciente
2.
Insects ; 15(6)2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38921164

RESUMO

This study investigates the distribution, morphology, and potential functions of antennal sensilla in various wasp species, including Dolichovespula flora, D. intermedia, Vespula structor, Vl. vulgaris, Provespa barthelemyi, Vespa bicolor, V. ducalis, V. mocsaryana, and V. velutina var. nigothorax. The study thoroughly analyzes the antennal structure of these species, representing all four genera of the yellow-jacket and hornet subfamily Vespinae. Using scanning electron microscopy (SEM), the study identifies a total of nineteen types of sensilla, including sensilla trichodea (ST-I, ST-II, ST-III), sensilla campaniform (SCF-I, SCF-II, SCF-III), pit organs (SCO-I, SCO-II, and SA), sensilla placodea (SP-I, SP-II), sensilla chaetica (SCH-I, SCH-II), sensilla basiconica (SB-I, SB-II), sensilla agmon (SAG-I, SAG-II), and sensilla coelocapitular (SCA). Additionally, tyloids were observed in the males of seven species, except for Vl. structor and Vl. vulgaris. The study provides insights into these sensilla types' morphology, abundance, and distribution. It discusses the variations in sensilla morphology among different species and the presence of gender-specific sensilla. This study provides new data about the morphology and distribution patterns of sensilla and tyloid.

3.
Open Life Sci ; 19(1): 20220885, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38911929

RESUMO

To evaluate the effects of varying proportions of yak meat in feed on the growth of rats and provide a theoretical basis for selecting the optimal feed proportion suitable for rats. This study was designed as a one-variable experiment. Fifty male rats were divided into five groups. The ratios of yak meat to basal feed of rats in four dietary treatment groups were 2:8, 4:6, 6:4, and 8:2, respectively, while those in the control group were only provided a basal diet. In the feeding experiment, the body weights of the rats were recorded on Day 0 and subsequently in the first, second, third, and fourth weeks, along with quantities of feed intake. The body and tail lengths, as well as the waist circumference of the rats, were measured, and blood samples were collected in the fourth week for routine blood and biochemistry investigations. The rats in the 4:6 feed group had the best body condition. They had normal body and tail lengths, smaller waist circumferences, good posture, and were in better overall health than rats in the other groups. The results indicate that the 4:6 diet was optimal for enhancing rats' growth performance compared to the other diets.

4.
Heliyon ; 10(3): e25060, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38314296

RESUMO

Previous research has identified a negative association between mobile phone addiction and time management disposition among college students; however, the direction of this relationship remains divergent. This study utilized a cross-lagged panel model to elucidate the directionality of the relationship between mobile phone addiction and time management disposition. A total of 466 college students completed two measures at seven-month intervals. The findings revealed a prevalence of mobile phone addiction at 10.94 % and 13.73 % in the two surveys. Notably, both mobile phone addiction and time management disposition demonstrated stability over time. Furthermore, a discernible negative bidirectional relationship was observed between the two. The present findings underscore the importance of timely intervention for college students facing challenges in mobile phone usage and time management.

6.
Clin Appl Thromb Hemost ; 29: 10760296231216966, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37997283

RESUMO

Venous thromboembolism (VTE) is a life-threatening postoperative complication of malignant tumors. We identified risk factors for postoperative VTE in patients undergoing radical resection of colorectal cancer (CRC) and constructed and validated a clinical prediction model. Clinical data of 982 patients undergoing radical resection of CRC from September 1, 2020, to March 31, 2022, in Ningxia Medical University General Hospital were analyzed retrospectively. Patients were randomly divided into training (n = 617) and validation groups (n = 264). Data included baseline characteristics, preoperative complications, examination results, and intraoperative and postoperative indicators. Logistic regression analysis was used to determine risk factors, build a predictive model, and draw a predictive nomogram (CRSPOT). Receiver operating characteristics (ROC) curve was used to calculate the area under the curve (AUC) for evaluating the model's predictive ability. Independent risk factors for postoperative VTE were as follows: postoperative hemoglobin of <10 g/L (odds ratio [OR] 0.413, 95% confidence interval [CI] 0.220-0.777), postoperative D-dimer of ≥3.5µg/mL (OR 2.156, 95% CI 1.145-4.061), BMI of ≥25 kg/m2 (OR 2.313, 95% CI 1.225-4.369), operation time of ≥4 h (OR 2.292, 95% CI 1.232-4.262), lower extremity varicose veins (OR 4.499, 95% CI 1.764-11.476), postoperative ileus (OR 5.760, 95% CI 2.031-16.337), and postoperative hypoxemia (OR 9.230, 95% CI 4.562-18.672). The nomogram's AUC was 0.826, demonstrating a reliable predictive ability. The CRSPOT nomogram reliably predicts postoperative VTE in patients undergoing radical resection of CRC, identifying high-risk patients early, allowing early implementation of antithrombotic strategies, and helping to reduce the incidence and mortality of postoperative VTE.


Assuntos
Neoplasias Colorretais , Tromboembolia Venosa , Humanos , Nomogramas , Estudos Retrospectivos , Tromboembolia Venosa/epidemiologia , Prognóstico , Modelos Estatísticos , Fatores de Risco , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/epidemiologia , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/complicações
7.
Front Microbiol ; 14: 1276493, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37808300

RESUMO

Orychophragmus violaceus is a local Brassicaceae in China, while most of it is directly mowed and discarded after the ornamental period. In order to develop forage resources, this study firstly evaluated the potential preservation of O. violaceus silage. O. violaceus was harvested at full-bloom stage, and ensiled without (CK) or with maize meal (Y5), lactic acid bacteria inoculant (Z) and compound additive (Y5Z) for 60 d. Results of chemical and microbiological analysis showed that a large amount of lactic acid was produced and the final pH value was below 4.1 in silages regardless of additive application. CK silage was well preserved as indicated by the low levels of dry matter loss and butyric acid content, and the predominant genus were identified as Enterococcus and Pediococcus. Y5 silage had potential health risks for humans and animals as seen by frequent occurrence of pathogenic bacteria Clostridium and Achromobacter. Z and Y5Z silages were poorly preserved, resulting in great dry matter loss and butyric acid content. Considering the abundant acetic acid production, the dominant Lactobacillus might possess a heterofermentative pathway in Z and Y5Z silages. In conclusion, O. violaceus has the potential to be long stored as silage because of its sufficient water-soluble carbohydrates, while exogenous lactic acid bacteria and maize meal generally provided little positive effect. In future research, efficient homofermentative Lactobacillus strains were suggested to be screened to further enhance the ensiling process of O. violaceus silage.

8.
Am J Case Rep ; 24: e940391, 2023 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-37491800

RESUMO

BACKGROUND Vasovagal syncope is a loss of consciousness caused by decreased arterial pressure and cerebral blood flow. The characteristic features of vasovagal syncope include cardiovascular inhibition caused by neural reflexes, accompanied by vasodilation and bradycardia. To date, there is little literature to report several episodes of syncope under spinal anesthesia during the perioperative period for drainage of an anal abscess. The purpose of this article is to alert clinical practitioners to the early identification of the underlying causes of vasovagal syncope and to facilitate timely and effective management strategies. CASE REPORT We present the case of a 44-year-old man with a perianal abscess who was scheduled for an incision and drainage procedure for the abscess under spinal anesthesia. Preoperative assessment revealed no history of cardiac disease, neurological disorders, or drug allergies. During the perioperative period, the patient experienced 3 episodes of syncope: 1 episode during puncture of spinal anesthesia, and the others at 6.5 h and 8.5 h after the procedure. The patient was discharged 4 days later, and a 30-day postoperative follow-up showed good recovery, without any episodes of syncope. CONCLUSIONS We described a case of 3 episodes of vasovagal syncope occurring in a patient during the perioperative period of drainage of perianal abscess under spinal anesthesia. Pain may have been the main cause of vasovagal syncope in this patient. To avoid vasovagal syncope, it is best for anesthesiologists to choose the lateral position to perform spinal anesthesia and to provide good perioperative pain management for these patients.


Assuntos
Raquianestesia , Doenças do Ânus , Síncope Vasovagal , Masculino , Humanos , Adulto , Síncope Vasovagal/etiologia , Raquianestesia/efeitos adversos , Abscesso/etiologia , Abscesso/cirurgia , Síncope , Drenagem/efeitos adversos , Dor
9.
Clin Cosmet Investig Dermatol ; 16: 751-767, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37016603

RESUMO

Objective: Treatment of burn wound healing involves infection, nutrition, psychology and rehabilitation, and proper nutritional support can promote wound healing, enhance immune function and reduce the incidence of complications. This study aimed to investigate the effects of feed containing yak meat on scalded rats' body condition and wound healing. Methods: Adopting a two-factor factorial design, the growth performance, food intake, body weight, and Lee's index of rats were measured. The wound conditions of scalded rats with different feeds (basic, basic + yak meat, and basic + yellow beef) were observed at different periods, and their wounds' hematoxylin and eosin (H&E) staining states were detected. The proliferating cell nuclear antigen (PCNA)-positive cells and apoptosis were analyzed to evaluate the effects of feed on the wound healing of scalded rats. Results: The feed intake was the highest in the yellow beef feed group and the lowest in the yak meat feed group. The body weight was the highest in the yak meat feed group and the lowest in the yellow beef feed group. Furthermore, 45 days after scalding, the obesity index in the yak beef feed group was the closest to that of the rats before scalding. The wound recovery of the rats in the yak meat feed group was the best at 30 days, and the H&E staining results also proved that the recovery effect of the scalded rats in the yak meat feed group was better than other two groups. According to the results of PCNA and apoptosis, the yak meat feed group had lower positive cell rate and faster wound healing. Conclusion: The rats in the yak meat feed group recovered better than those in the other groups, and the yak beef feed had the best effect on the wound healing of the scalded rats.

10.
J Am Chem Soc ; 145(9): 5506-5511, 2023 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-36790023

RESUMO

Given prominent physicochemical similarities between H2O2 and water, we report a new strategy for promoting the peroxygenase activity of P450 enzymes by engineering their water tunnels to facilitate H2O2 access to the heme center buried therein. Specifically, the H2O2-driven activities of two native NADH-dependent P450 enzymes (CYP199A4 and CYP153AM.aq) increase significantly (by >183-fold and >15-fold, respectively). Additionally, the amount of H2O2 required for an artificial P450 peroxygenase facilitated by a dual-functional small molecule to obtain the desired product is reduced by 95%-97.5% (with ∼95% coupling efficiency). Structural analysis suggests that mutating the residue at the bottleneck of the water tunnel may open a second pathway for H2O2 to flow to the heme center (in addition to the natural substrate tunnel). This study highlights a promising, generalizable strategy whereby P450 monooxygenases can be modified to adopt peroxygenase activity through H2O2 tunnel engineering, thus broadening the application scope of P450s in synthetic chemistry and synthetic biology.


Assuntos
Sistema Enzimático do Citocromo P-450 , Peróxido de Hidrogênio , Peróxido de Hidrogênio/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Heme/química
11.
J Autoimmun ; 134: 102975, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36527784

RESUMO

Small GTPases play critical roles in cell morphology, movement, and adhesion by dynamic regulation of actin cytoskeleton. The small Rho GTPase Rif/RhoF (Rho in filopodia) regulates the formation of filopodia and stress fibers in cells. Rif is highly expressed in a number of cell types in the immune system; however, it's role in immune system function is unclear. In this research, we found that Rif expression is necessary for NF-κB activation in primary immune cells, and mature dendritic cell (mature DCs) induced from Bone Marrow-Derived Dendritic Cells (BMDCs) isolated from Rif knock out (Rif KO) mice displayed impaired degradation of I-κBα, as well as reduced TNF-α secretion and p38 MAPK phosphorylation under LPS stimulation. Interestingly, we revealed that TLR agonists, such as LPS and poly (I:C), as well as bacterial virulence factor SopE could induce a transient increase in Rif activation in monocytes THP-1 cells. Furthermore, Rif was found to be an integral part of the TLR4, TLR3 and nodosome signaling complex. We further identified Src tyrosine kinases as upstream activator of Rif in both bacterial and viral induced immune responses. Moreover, activated Rif induces activation of transcription factors, such as NF-κB, AP-1 and IRF-3, and mediates inflammation through secretion of IL-6, IL-8 or TNFα. Rif activation by PRRs contributes in a variety of ways to protective host responses against invading microbes. Taken together, this study reveals that Rif is indispensable for both extracellular and intracellular pattern-recognition receptor-mediated innate immune responses. Rif possess broad anti-pathogenic effect and understanding of the molecular mechanisms by which this small Rho GTPase interferes with innate immune system will be beneficial to develop therapies against infectious agents.


Assuntos
Lipopolissacarídeos , NF-kappa B , Animais , Camundongos , Imunidade Inata , Lipopolissacarídeos/farmacologia , NF-kappa B/metabolismo , Receptores de Reconhecimento de Padrão , Transdução de Sinais , Proteínas rho de Ligação ao GTP/metabolismo
12.
Dalton Trans ; 51(48): 18622-18632, 2022 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-36448337

RESUMO

Multi-component nano-oxide composite materials may present special synergistic effects as anode materials for lithium-ion batteries. Mesoporous ß-MnO2/Mn3O4 composite nanotubes are built here via controlling the deoxidation process of carbon-coating to induce a partial phase transition of high valence manganese dioxides. Compared to single ß-MnO2 nanotubes or Mn3O4@C nanotubes, the mesoporous ß-MnO2/Mn3O4@C composite nanotubes exhibit superior electrochemical properties. 679 mA h g-1 of reversible specific capacity and 86% of capacity retention after 1000 cycles at 1 A g-1 current density are obtained. The excellent performance is attributed to the unique multiple phase transitions regulation phenomena of manganese oxide occurring in the ß-MnO2/Mn3O4 composite material during the electrochemical processes, which significantly extends the cycle life of the ß-MnO2/Mn3O4 composite material.

13.
Front Oncol ; 12: 828160, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36313626

RESUMO

Background: Breast cancer is the second cause of cancer death in women, and tumor metastasis is the primary cause of mortality. Due to the involvement of many regulatory molecules and signaling pathways, the occurrence and development of metastases needs to be further studied. MicroRNAs (miRNAs) are ubiquitously expressed small non-coding RNAs that have been shown to play an important role in the diagnosis and treatment of many diseases, as well as representing an attractive candidate for metastasis control. In this study, we investigated the mechanism of potassium piperonate (GBK) in impairing breast cancer cell invasion and metastasis by targeting miR-31. Methods: Breast cancer cells, either treated with GBK or left untreated, were assessed for migration and invasion capacities using wound healing and transwell assays. GBK-targeted miRNAs were identified and verified using RT-qPCR. Western blotting was used to validate the changes in expression levels of miR-31-targeted genes. Methylation specific PCR was performed to detect the effect of GBK on the methylation levels of the lncRNA LOC554202 host gene. The synergistic effect of GBK and the chemotherapy drug cisplatin (DDP) on breast cancer cells was verified using cell proliferation, colony formation, and RT-qPCR assays in vitro, and the tumor xenograft model in vivo. Results: We found that miR-31 was the main target of GBK. GBK treatment affected the epigenetic modification at CpG sites by downregulating DNA methyltransferases. Thus, the CpG-associated methylation levels of lncRNA LOC554202 decreased significantly, and in turn upregulated both miR-31 and its host gene LOC554202 in breast cancer cells. We also observed the significant inhibition of miR-31-targeted genes following GBK treatment, including RHOA, WAVE3, and SATB2, with functions closely related to cancer cell invasion, migration, and proliferation. Furthermore, we revealed that the combination of GBK and DDP had a synergistic effect on inhibiting the proliferation of breast cancer cells in vitro and in vivo, especially in triple negative breast cancer (TNBC). Conclusions: This study investigated the target of GBK in the inhibition of breast cancer migration and invasion, and the underlying mechanisms involved, providing theoretical support for the development of GBK as an auxiliary drug for clinical treatment.

14.
Environ Sci Pollut Res Int ; 29(2): 1845-1857, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34363165

RESUMO

Pennisetum grasses (P. purpureum Schumach. 'Purple', P. alopecuroides (L.) Spreng. 'Liren' and P. alopecuroides (L.) Spreng. 'Changsui'), and a cadmium (Cd) hyperaccumulator (Thlaspi caerulescens J.Presl & C.Presl), were grown in soil with four Cd addition levels of 0, 2, 20 and 200 mg/kg. Toxicity symptoms were not observed although growth of all plants decreased as Cd addition increased. Shoot bioconcentration factor (BCFS), the translocation factor (TF) and shoot accumulation of Cd for most plants first increased and then declined as Cd concentrations increased. In contrast, the root bioconcentration factor (BCFR) for T. caerulescens declined and root Cd accumulation for T. caerulescens and two P. alopecuroides cultivars increased consistently as Cd levels increased. P. purpureum had the largest biomass with shoot Cd accumulation similar to that of T. caerulescens, despite lower foliar Cd concentration. Although shoot Cd concentrations of two P. alopecuroides cultivars were lower than for P. purpureum, root Cd concentrations were greater. P. purpureum had Cd BCFS and TF (> 1) at 2- and 20-mg/kg Cd addition treatments, similar to T. caerulescens. P. alopecuroides cultivars had Cd BCFR (> 1) and TF (< 1) at all Cd levels. Roots did not affect rhizosphere pH. However, concentrations of acid extractable Cd in rhizosphere soil were lower than those of corresponding non-rhizosphere soil at all Cd levels for T. caerulescens and P. purpureum; T. caerulescens and P. purpureum did not affect less bioavailable Cd fractions. Concentrations of acid extractable Cd in the rhizosphere of the P. alopecuroides cultivars were not reduced at any Cd level. Differences in Cd accumulation among the three Pennisetum grasses were mainly attributable to root biomass and Cd TFs rather than rhizosphere Cd mobility.


Assuntos
Pennisetum , Poluentes do Solo , Thlaspi , Biodegradação Ambiental , Cádmio/análise , Raízes de Plantas/química , Rizosfera , Solo , Poluentes do Solo/análise
15.
J Chromatogr A ; 1661: 462692, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34883355

RESUMO

Facile and sensitive determination of plant growth regulators (PGRs) in food samples is important but still remains great challenge. Herein, a pipette tip solid phase extraction (PT-SPE) method was developed for fast and sensitively detecting PGRs. The PT-SPE adsorbent was prepared by integrating a novel covalent organic framework (COF) of schiff base network 3 (SNW-3) and polyacrylonitrile (PAN) through electrospinning. The SNW-3 can easily adsorb PGRs with high special affinity through electrovalent bands between the ammonium ions of SNW-3 and the carboxy groups of PGRs. The polymer of PAN acts as scaffold material for SNW-3, which can lower seepage pressure hence accelerates adsorption/desorption kinetics. By combination with HPLC-DAD, a satisfactory method was successfully developed for simultaneous determination of ten PGRs in watermelon. Good analytical performances were achieved with this proposed method, including good linearity (5-500 ng/mL) with high correlation coefficients (R ≥ 0.9981), low limits of detection (S/N = 3, 0.24-3.19 ng/mL) and limits of quantification (S/N = 10, 1.65-5.72 ng/mL), satisfactory precision (intra-day RSDs ≤ 2.7%, inter-day RSDs ≤ 3.7%), and high accuracy (recovery: 82.8-113.0%). The method developed in this study shows high potential for design of high target-affinity adsorbents for food sample preparing.


Assuntos
Estruturas Metalorgânicas , Nanofibras , Resinas Acrílicas , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Reguladores de Crescimento de Plantas , Extração em Fase Sólida
16.
Front Pharmacol ; 12: 706240, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34658851

RESUMO

Geminin, an inhibitor of the DNA replication licensing factor, chromatin licensing and DNA replication factor (Cdt) 1, is essential for the maintenance of genomic integrity. As a multifunctional protein, geminin is also involved in tumor progression, but the molecular details are largely unknown. Here, we found that lysophosphatidic acid (LPA)-induced upregulation of geminin was specific to gastric cancer cells. LPA acted via LPA receptor (LPAR) 3 and matrix metalloproteinases (MMPs) signaling to transactivate epidermal growth factor receptor (EGFR) (Y1173) and thereby stabilize geminin expression level during the S phase. LPA also induced the expression of deubiquitinating protein (DUB) 3, which prevented geminin degradation. These results reveal a novel mechanism underlying gastric cancer progression that involves the regulation of geminin stability by LPA-induced EGFR transactivation and provide potential targets for the signaling pathway and tumor cell-specific inhibitors.

17.
Opt Express ; 29(18): 28767-28777, 2021 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-34614999

RESUMO

In this paper, a metamaterial structure with radar and infrared (IR) compatible stealth characteristics is designed based on the principle of plasmonic absorbing structure (PAS). Due to the lack of reports on PAS-based IR radar compatible stealth, this article combines PAS and IR frequency selective surfaces to achieve the desired purpose. Through mathematical modeling and dispersion engineering of the unit cell proposed, a PAS with ultra-wideband wave absorption is realized. The low emissivity of the IR atmospheric window band is realized by means of the simulation and analysis of the IR frequency selective surface with different indium tin oxide (ITO) occupation ratios. The absorptivity of designed structure is higher than 90% from 4GHz to 28.6GHz, and the emissivity of the IR atmospheric window is only 0.3. The experience of the fabricated sample is consistent with the theoretical analysis and the simulation. Our method enriches the implementation strategies of radar-IR compatibility and has reference significance for multi-spectrum compatible stealth.

18.
Artigo em Inglês | MEDLINE | ID: mdl-34501662

RESUMO

Metabolic syndrome (MetS) increases with age, obesity, low physical activity, and decreased muscle strength. Although many studies have reported on grip strength and MetS, few studies have been conducted on leg strength. The purpose of this study was to analyze the prevalence of MetS according to absolute and relative leg strength values in middle-aged and older women. The participants were 1053 women who visited the healthcare center: middle-aged (n = 453) and older (n = 601). MetS was diagnosed using the criteria established by the third report of the National Cholesterol Education Program Adult Treatment Panel III and the World Health Organization's Asia Pacific guidelines for waist circumference. For leg strength, knee flexion and extension were performed using isokinetic equipment. Grip strength was measured using a grip dynamometer and classified into quartiles. Analysis of prevalence using logistic regression showed that MetS was present in 21.2% of middle-aged and 39.4% of older women. The lowest relative leg extension increased 2.5 times in the middle-aged and 1.5 times in older women (p < 0.05). However, leg flexion did not have a significant prevalence in either age group. The prevalence of MetS in middle-aged and older women with the lowest relative grip strength increased 1.5 and 1.2 times, respectively. Conversely, the lower the absolute leg extension strength, the lower the MetS prevalence was at 0.520 in middle-aged and 0.566 in older women (p < 0.05). In conclusion, the prevalence of MetS increased in women with low relative grip and leg strengths. Specifically, the lower the relative leg extension muscle strength, the higher the prevalence of MetS. In addition, the prevalence of MetS increased in the high-frequency alcohol consumption and non-physical activity group.


Assuntos
Síndrome Metabólica , Adulto , Idoso , Estudos Transversais , Feminino , Força da Mão , Humanos , Síndrome Metabólica/epidemiologia , Pessoa de Meia-Idade , Força Muscular , Prevalência , Circunferência da Cintura
19.
Opt Express ; 29(14): 22108-22116, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34265982

RESUMO

Optically transparent metamaterials with the performance of infrared radar compatible stealth have been designed and manufactured on the basis of the continuous in-depth research on single-band stealth technology. In this paper, metamaterials are designed through theoretical calculations and modeling simulations. The designed structure can achieve higher than 90% broadband (8.7-32 GHz) absorption at wide-angle (45 degrees), emissivity of 0.3 in infrared atmospheric window, and optical transparency. In addition, the material can be bent, which greatly expands its application scenarios. The experimental results are consistent with the theoretical calculation and simulation results.

20.
Anal Chem ; 93(23): 8219-8227, 2021 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-34075758

RESUMO

Facile and sensitive determination of formaldehyde (FA) in indoor environments still remains challenging. Herein, a fluorescent probe, termed PHN@MOF, was synthesized by embedding the fluorescent molecule of N-propyl-4-hydrazine-naphthalimide (PHN) into a metal-organic framework (MOF) for sensitive and visual monitoring of FA. The hydrazine group of PHN acts as the specific reaction group with FA based on the condensation reaction. The host of MOF (UiO-66-NH2) offers the surrounding confinement space required for the reaction. Owing to the enrichment effect and molecular sieve selection of UiO-66-NH2 to FA, PHN@MOF, compared with free PHN, exhibits very high sensitivity and selectivity based on space confinement-induced sensitivity enhancement (SCISE). Moreover, the fluorescence of UiO-66-NH2 offers a reference signal for FA detection. Using this ratiometric fluorescent PHN@MOF probe, a colorimetric gel plate and test paper were developed and used to visually monitor FA in air.


Assuntos
Estruturas Metalorgânicas , Naftalimidas , Aldeídos , Corantes Fluorescentes , Espectrometria de Fluorescência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...