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2.
Adv Mater ; : e2202309, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35535384

RESUMO

Cholesteric liquid crystals (CLC) are chiral supramolecular systems that self-assemble into a highly regular helical arrangement in liquid crystals (LCs) medium. Such an arrangement is highly beneficial for the chiral enlargement effect on circularly polarized luminescence (CPL) signals. Dichroic dyes with rod-like molecular structures can exhibit fluorescence anisotropy along both the long and short molecular axes owing to their transition dipole moment (TDM) vectors. We have prepared a pair of donor-accepter (D-A) achiral dichroic dyes, namely, 3,4-ethylenedioxythiophene derivative (P1, whose TDM vector is parallel to the long axis of the molecule, i.e., F|| >F⊥ ) and anthraquinone derivative (N1, whose TDM vector is perpendicular to the long axis of the molecule, i.e., F||

3.
Analyst ; 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35535706

RESUMO

In the operation using sevoflurane as an anesthetic, some patients, especially children, will have agitation symptoms after awakening from anesthesia. The incidence of agitation is about 20%, and current detection methods cannot predict the probability of a patient with agitation. In this paper, a magnetic field enhanced photoelectron ionization (MEPEI) miniature time-of-flight mass spectrometer (TOFMS) was developed for point-of-care detection and verification of the relationship between postoperative agitation symptoms and sevoflurane concentration in exhaled breath. The MEPEI source is water vapor resistant and can directly ionize sevoflurane via capillary sampling and obtain its characteristic ion [C4H3F6O]+ (m/z 181), and the analysis time of exhaled breath is only 60 s. Three standard curves of 0.5-80 ppmv, 80-2000 ppmv and 2000-15 000 ppmv were formulated to quantitatively detect sevoflurane in different scenarios, the coefficient of determination (R2) was higher than 0.9882 and the relative standard deviation (RSD) of signal intensity was only 1.24%. The results indicated that four of the 46 child patients had agitation symptoms. Partial least squares-discriminant analysis (PLS-DA) was performed to analyze the data, and an identification and treatment strategy was established for child patients with agitation symptoms. The new miniature MEPEI-TOFMS was also successfully used to evaluate the concentration of sevoflurane in a medical environment. The real-time monitoring of sevoflurane concentration in exhalation indicates the potential of this method for low-cost and convenient point-of-care (POC) detection and diagnosis of agitation symptoms.

4.
Int J Biol Macromol ; 2022 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-35504419

RESUMO

A novel acidic polysaccharide named SSPA50-1 was isolated from Scapharca subcrenata using a simulated gastric fluid extraction method. SSPA50-1 is a heteropolysaccharide with an average molecular weight of 44.7 kDa that is composed of galacturonic acid, glucose, galactose, mannose, ribose, rhamnose, fucose, xylose and arabinose at a molar ratio of 1.00:5.40:9.04:3.10:1.59:4.01:2.10:2.21:2.28. The structural characterization based on the methylation and 1D/2D NMR analyses indicated that SSPA50-1 is composed of →3)-ß-L-Rhap-(1→,→3)-ß-L-2-O-Me-Fucp-(1→, →2)-α-D-Xylp-(1→, →5)-α-L-Araf-(1→, →3)-ß-D-Galp-(1→, →6)-α-D-Glcp-(1→, →3,4)-ß-D-Manp-(1→, →3,4)-ß-D-Galp-(1→, ß-D-Ribf-(1→, α-D-Glcp-(1→, and α-D-GalAp6Me-(1→. Furthermore, SSPA50-1 possessed potent immunoregulatory activity by enhancing the phagocytosis and NO, iNOS, TNF-α and IL-6 secretion capacity of RAW 264.7 cells. Otherwise, SSPA50-1 significantly promoted the proliferation of splenic lymphocytes and RAW264.7 macrophages. These results indicated that SSPA50-1 could be developed as a potential ingredient for immunostimulatory agents.

5.
J Hum Hypertens ; 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35523856

RESUMO

Hydrochlorothiazide is the most common thiazide diuretic used for hypertension in the US. Yet, hypokalaemia is a well-recognised adverse effect. To evaluate the prevalence and factors associated with hypokalaemia (serum potassium < 3.5 mmol/L) among hydrochlorothiazide users, we included US adults aged ≥20 years in the 1999-2018 National Health and Nutrition Examination Survey. Participants were categorised according to the use of hydrochlorothiazide and other antihypertensive agents. Factors associated with hypokalaemia, including demographics and prescription patterns (monotherapy vs single-pill fixed-dose combination vs polytherapy) were studied using multivariable logistic regression. Hypokalaemia was present in 12.6% of the hydrochlorothiazide users, equivalent to ~2.0 million US adults. Women (adjusted OR, 2.22; 95% CI, 1.74-2.83), non-Hispanic blacks (adjusted OR, 1.65; 95% CI, 1.31-2.08), underweight (adjusted OR, 4.33; 95% CI, 1.34-13.95), and participants taking hydrochlorothiazide for five years or more (adjusted OR, 1.47; 95% CI, 1.06-2.04) had a higher risk of hypokalaemia. Compared to monotherapy, fixed-dose combination therapy (adjusted OR, 0.32; 95% CI, 0.21-0.48) was associated with the lowest risk. Among those taking potassium supplements, hypokalaemia was found in 27.2% of participants on monotherapy and 17.9% on polytherapy. The prevalence of hypokalaemia among hydrochlorothiazide users was considerable, even among participants who also took potassium supplements. Women, ethnic minorities, underweight, monotherapy, and participants with long-term therapy are more likely to have hypokalaemia. Regular monitoring of potassium and combination with potassium-sparing drugs are needed.

6.
Crit Rev Food Sci Nutr ; : 1-19, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35574653

RESUMO

Dietary intake of caffeine has significantly increased in recent years, and beneficial and harmful effects of caffeine have been extensively studied. This paper reviews antioxidant and anti-inflammatory activities of caffeine as well as its protective effects on cardiovascular diseases, obesity, diabetes mellitus, cancers, and neurodegenerative and liver diseases. In addition, we summarize the side effects of long-term or excessive caffeine consumption on sleep, migraine, intraocular pressure, pregnant women, children, and adolescents. The health benefits of caffeine depend on the amount of caffeine intake and the physical condition of consumers. Moderate intake of caffeine helps to prevent and modulate several diseases. However, the long-term or over-consumption of caffeine can lead to addiction, insomnia, migraine, and other side effects. In addition, children, adolescents, pregnant women, and people who are sensitive to caffeine should be recommended to restrict/reduce their intake to avoid potential adverse effects.

7.
Chem Commun (Camb) ; 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35537125

RESUMO

The brevijanazines are novel p-nitrobenzoylated piperazines isolated from Aspergillus brevijanus. Their structures were elucidated by spectroscopic analysis, X-ray crystallography and total synthesis. Heterologous biosynthesis, precursor feeding and in vitro microsomal assays unveiled the biosynthetic pathway to the brevijanazines, featuring a cytochrome P450 oxygenase that converts p-aminobenzoic acid to p-nitrobenzoic acid.

8.
J Am Heart Assoc ; 11(10): e024060, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35574957

RESUMO

Background Strategies to improve long-term prediction of heart failure and death in valvular surgery are urgently needed because of an increasing number of procedures globally. This study sought to report the prevalence, changes, and prognostic implications of concomitant hepatorenal dysfunction and malnutrition in valvular surgery. Methods and Results In 909 patients undergoing valvular surgery, 3 groups were defined based on hepatorenal function (the modified model for end-stage liver disease excluding international normalized ratio score) and nutritional status (Controlling Nutritional Status score): normal hepatorenal function and nutrition (normal), hepatorenal dysfunction or malnutrition alone (mild), and concomitant hepatorenal dysfunction and malnutrition (severe). Overall, 32%, 46%, and 19% of patients were classified into normal, mild, and severe groups, respectively. Over a 4.1-year median follow-up, mild and severe groups incurred a higher risk of mortality (hazard ratio [HR], 3.17 [95% CI, 1.40-7.17] and HR, 9.30 [95% CI, 4.09-21.16], respectively), cardiovascular death (subdistribution HR, 3.29 [95% CI, 1.14-9.52] and subdistribution HR, 9.29 [95% CI, 3.09-27.99]), heart failure hospitalization (subdistribution HR, 2.11 [95% CI, 1.25-3.55] and subdistribution HR, 3.55 [95% CI, 2.04-6.16]), and adverse outcomes (HR, 2.11 [95% CI, 1.25-3.55] and HR, 3.55 [95% CI, 2.04-6.16]). Modified model for end-stage liver disease excluding international normalized ratio and controlling nutritional status scores improved the predictive ability of European System for Cardiac Operative Risk Evaluation (area under the curve: 0.80 versus 0.73, P<0.001) and Society of Thoracic Surgeons score (area under the curve: 0.79 versus 0.72, P=0.004) for all-cause mortality. One year following surgery (n=707), patients with persistent concomitant hepatorenal dysfunction and malnutrition (severe) experienced worse outcomes than those without. Conclusions Concomitant hepatorenal dysfunction and malnutrition was frequent and strongly linked to heart failure and mortality in valvular surgery.

9.
J Clin Neurosci ; 101: 67-79, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35561433

RESUMO

BACKGROUND: Gamma knife radiosurgery (GKRS) has been deemed as the gold standard stereotactic radiosurgery (SRS) mode for the treatment of intracranial tumors, cerebrovascular diseases and brain functional diseases. Our study was aimed to systematically evaluate the efficacy, safety, and complications of gamma knife radiosurgery for trigeminal schwannomas. METHOD: We performed a systematic review and meta-analysis to analyze the clinical outcomes of patients with trigeminal schwannomas treated primarily or adjunctly with GKRS. We searched two databases, Pubmed and Embase, for studies published before January 1, 2021, using GKRS for trigeminal schwannomas. Studies reporting treatment of other schwannomas, or other forms of SRS such as linear accelerator and Cyberknife were excluded to reduce its heterogeneity. RESULTS: Our search achieved 351 studies, of which 35 were assessed for full-text eligibility. 19 studies were included in the meta-analysis. 456 of 504 patients (0.94, 95% CI 0.91-0.96, I2 = 3.02%, p < 0.01) from 18 studies had local control, and 278 of 489 patients (0.63, 95%CI 0.48-0.78, I2 = 88.75%, p < 0.01) from 16 studies experienced tumor regression or disappearance. 231 of 499 patients (0.50, 95% CI 0.37-0.62; I2 = 83.89%, P < 0.01) from 17 studies had clinical symptoms improved. There was no significant difference in tumor control between those treated with GKRS as either primary treatment or adjuvant to surgery(p = 0.390). CONCLUSION: GKRS is an efficacious primary and adjuvant method of treating trigeminal schwannomas, with reliable tumor control rates. Randomized controlled trials are needed to further and comprehensively evaluate the benefit-to-risk ratio of gamma knife radiosurgery.

10.
Microb Ecol ; 2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35437690

RESUMO

Dam construction and impoundment cause discontinuities in the natural biophysical gradients in rivers. These discontinuities may alter distinctive habitats and different microbial community assembly mechanisms upstream and downstream of dams, which reflect the potential impacts of damming on riverine aquatic ecosystems. In this study, we investigated the planktonic microbial assemblages of three large dams in the upper Yangtze River by using high-throughput sequencing. The results revealed that the alpha diversity indexes increased downstream of the dams. In addition, more eukaryotic ASVs solely occurred downstream of the dams, which indicated that a large proportion of eukaryotes appeared downstream of the dams. The nonmetric multidimensional scaling analysis indicated that there was no obvious geographic clustering of the planktonic microbial assemblages among the different locations or among the different dams. However, the dam barriers changed dam-related variables (maximum dam height and water level) and local environmental variables (water temperature, DOC, etc.) that could possibly affect the assembly of the planktonic microbial communities that are closest to the dams. A co-occurrence network analysis demonstrated that the keystone taxa of the planktonic bacteria and eukaryotes decreased downstream of the dams. In particular, the keystone taxa of the eukaryotes disappeared downstream of the dams. The robustness analysis indicated that the natural connectivity of the microbial networks decreased more rapidly upstream of the dams, and the downstream eukaryotic network was more stable. In conclusion, damming has a greater impact on planktonic eukaryotes than on bacteria in near-dam areas, and planktonic microbial assemblages were more susceptible to the environmental changes. Our study provides a better understanding of the ecological effects of river damming.

11.
Sci Total Environ ; 832: 155061, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35395299

RESUMO

Response surface methodology (RSM) has been widely used to identify optimal conditions for environmental microorganisms to maximize degrading pollutants and accumulating biomass. However, to date, environmental impact and economic cost have rarely been considered. In this study, a single cell of microalgae Chlorella sorokiniana ZM-5 was sorted, and its enrichment was carried out for the first time. The optimized conditions by RSM for achieving the highest COD, TN, TP removal and 352.61 mg/g lipid production were 24 h light time, 4.3:1C/N, 7.2 pH, and 30 °C temperature, respectively. Life-cycle approaches were then carried out upon this illustrative case, and the results indicated that the implementation of the above optimal conditions could reduce the total environmental impact by 48.0% and the total economic impact by 10.2%. This study showed the feasibility of applying life-cycle approaches to examine the optimal conditions of a biological process in terms of minimizing environmental impact and economic costs.

12.
Artigo em Inglês | MEDLINE | ID: mdl-35367469

RESUMO

BACKGROUND: Exposure to traffic-related air pollution is associated with increased morbidity and mortality. Negative health impact of diesel exhaust (DE) exposure may in part be mediated via epigenetic modulation. Ten-eleven translocation (TET) enzymes catalyze the active DNA demethylation process and play important roles in epigenetic regulation. OBJECTIVES: We sought to assess the expression of TET enzymes in human PBMCs and the differentiation of immune subsets in response to acute DE exposure at a range of concentrations. METHODS: Thirteen healthy participants were recruited for this randomized, double-blind, controlled human exposure study to DE. In this 4-arm crossover study, each participant was exposed for 4 hours to 3 different concentrations of DE (DE diluted to have particulate matter with a diameter of ≤2.5 micron concentration nominally set at 20, 50, and 150 µg/m3) and filtered air. Blood was collected at baseline and 4 and 24 hours after the exposure start time. The composition of PBMCs and their TET enzymes' expression were evaluated with flow cytometry. Cytokines in plasma were measured by electrochemiluminescence multiplex assays. RESULTS: DE exposure decreased the proportion of B cells, TH17 cells, and activated T cells in PBMCs. TET enzymes were upregulated in PBMCs, especially in TH1, TH2, and TH17 cells, at 4 hours following DE exposure. The expression of TET enzymes correlated with proinflammatory cytokine secretion in plasma. CONCLUSIONS: We demonstrated that acute DE exposure impacted peripheral blood leukocyte proportions and TET enzymes' expression in lymphocyte subsets at DE concentration of 50 µg/m3 and above. Our finding suggests that even a modest exposure to air pollution can impact the circulating immune cells via epigenetic modulation.

13.
J Environ Sci (China) ; 114: 66-74, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35459515

RESUMO

Ammonia (NH3) is ubiquitous in the atmosphere, it can affect the formation of secondary aerosols and particulate matter, and cause soil eutrophication through sedimentation. Currently, the use of radioactive primary reagent ion source and the humidity interference on the sensitivity and stability are the two major issues faced by chemical ionization mass spectrometer (CIMS) in the analysis of atmospheric ammonia. In this work, a vacuum ultraviolet (VUV) Kr lamp was used to replace the radioactive source, and acetone was ionized under atmospheric pressure to obtain protonated acetone reagent ions to ionize ammonia. The ionization source is designed as a separated three-zone structure, and even 90 vol.% high-humidity samples can still be directly analyzed with a sensitivity of sub-ppbv. A signal normalization processing method was designed, and with this new method, the quantitative relative standard deviation (RSD) of the instrument was decreased from 17.5% to 9.1%, and the coefficient of determination was increased from 0.8340 to 0.9856. The humidity correction parameters of the instrument were calculated from different humidity, and the ammonia concentrations obtained under different humidity were converted to its concentration under zero humidity condition with these correction parameters. The analytical time for a single sample is only 60 sec, and the limit of detection (LOD) was 8.59 pptv (signal-to-noise ratio S/N = 3). The ambient measurement made in Qingdao, China, in January 2021 with this newly designed CIMS, showed that the concentration of ammonia ranged from 1 to 130 ppbv.


Assuntos
Acetona , Amônia , Íons/química , Espectrometria de Massas/métodos , Vácuo
14.
Cell ; 185(8): 1356-1372.e26, 2022 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-35395179

RESUMO

Tumor-resident intracellular microbiota is an emerging tumor component that has been documented for a variety of cancer types with unclear biological functions. Here, we explored the functional significance of these intratumor bacteria, primarily using a murine spontaneous breast-tumor model MMTV-PyMT. We found that depletion of intratumor bacteria significantly reduced lung metastasis without affecting primary tumor growth. During metastatic colonization, intratumor bacteria carried by circulating tumor cells promoted host-cell survival by enhancing resistance to fluid shear stress by reorganizing actin cytoskeleton. We further showed that intratumor administration of selected bacteria strains isolated from tumor-resident microbiota promoted metastasis in two murine tumor models with significantly different levels of metastasis potential. Our findings suggest that tumor-resident microbiota, albeit at low biomass, play an important role in promoting cancer metastasis, intervention of which might therefore be worth exploring for advancing oncology care.


Assuntos
Neoplasias da Mama , Microbiota , Metástase Neoplásica , Animais , Neoplasias da Mama/microbiologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Feminino , Humanos , Neoplasias Pulmonares/patologia , Camundongos , Células Neoplásicas Circulantes/patologia
15.
Carbohydr Polym ; 289: 119467, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35483864

RESUMO

The excessive inflammation, oxidative stress, and impaired angiogenesis are major factors leading to difficulties in chronic wound healing. To develop bioactive materials with intrinsic antioxidant and anti-inflammatory properties, we prepared hydrogels for the first time using paramylon secreted by Euglena gracilis which is a polysaccharide has been approved by FDA as food additive. Results showed that the paramylon hydrogel has favourable anti-inflammatory effects and the ability to scavenge reactive oxygen species (ROS) through free radical destruction, deoxygenation, and singlet oxygen quenching, and inhibit ROS production by chelating the metal ions required for the formation of ROS. We found that the paramylon hydrogel could effectively reduce wound inflammation and promote angiogenesis to facilitate wound repair. Furthermore, for the first time, we found that paramylon hydrogel could promote the formation of blood vessels via the HIF-1α-VEGF pathway. These results indicated that the highly bioactive paramylon could be the preferred material for wound healing.


Assuntos
Hidrogéis , Cicatrização , Glucanos , Humanos , Hidrogéis/farmacologia , Inflamação , Espécies Reativas de Oxigênio/metabolismo
16.
RSC Adv ; 12(10): 6018-6024, 2022 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-35424549

RESUMO

Nanowelding of two crossing amorphous SiO x nanowires induced by uniform electron beam irradiation at room temperature was demonstrated in an in situ transmission electron microscope. It was observed that, under the electron beam irradiation, the amorphous nanowires became unstable driven by nanocurvature non-uniformly distributed over the nanowire surface centered around the crossing site of the nanowires. Such an instability of the nanowires could give rise to an athermal fast and massive migration of atoms nearby the surface centered around the crossing site, and thus the two crossing nanowires become gradually welded. The existing knock-on mechanism and molecular dynamics simulations seem inadequate to explain the observed athermal migration of the surface atoms and the resulting structural change at the nanoscale. To elucidate the observed phenomena of nanowelding, a mechanism of athermal atomic diffusion driven by the effects of the nanocurvature as well as the athermal activation of the electron beam was proposed and simulated. The simulation revealed the detailed process of the nanowelding and corresponding effects of the nanocurvature and athermal activation of the electron beam. In doing so, the nanowelding parameters became predictable, controllable, and tunable to a desired welding effect.

17.
Front Nutr ; 9: 853846, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35445053

RESUMO

Tea (Camellia sinensis L.) is a very popular health drink and has attracted increasing attention in recent years due to its various bioactive substances. Among them, L-theanine, a unique free amino acid, is one of the most important substances in tea and endows tea with a special flavor. Moreover, L-theanine is also a bioactive compound with plenty of health benefits, including antioxidant, anti-inflammatory, neuroprotective, anticancer, metabolic regulatory, cardiovascular protective, liver and kidney protective, immune regulatory, and anti-obesity effects. Due to the unique characteristics and beneficial functions, L-theanine has potential applications in the development of functional foods. This review summarized the influencing factors of L-theanine content in teas, the main health benefits and related molecular mechanisms of L-theanine, and its applications in food, understanding of which can provide updated information for the further research of L-theanine.

18.
BMC Nephrol ; 23(1): 155, 2022 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-35459111

RESUMO

BACKGROUND: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) may coexist with rheumatoid arthritis (RA). However, it is unclear whether the manifestations of AAV with and without coexisting RA are similar. This observational study aimed to investigate the clinicopathological manifestations of AAV with coexisting RA and to explore potential predictors for identifying AAV superimposed on RA. METHODS: Patients with both AAV and RA were identified by searching our hospital database and the literature. Data including age, sex, clinical manifestation, laboratory tests, renal pathology, and therapeutic regimens were retrieved. To assess the difference in clinical features and renal pathology between AAV patients with and without RA, we conducted 1:4 matched case-control studies. RESULTS: A total of 47 patients were identified, 15 from our hospital and 32 from the literature, and 33 (70.2%) were women. AAV was diagnosed later than RA in 83.0% of the patients and manifested as microscopic polyangiitis (MPA) in 78.7% of the patients. The kidney was the most frequently involved extra-articular organ (74.5%), followed by the lung (51.1%), and skin (8.5%). Patients with both AAV and RA were more likely to be asymptomatic (26.7% vs 3.3%, p = 0.013) than those with isolated AAV. However, they did not differ in other clinicopathological features. In RA patients, those with ANCA associated glomerulonephritis, were more likely to have decreased renal function at renal biopsy as opposed to those with primary glomerulonephritis. CONCLUSIONS: AAV can coexist with RA. In this coexistence, AAV usually develops after RA, is more likely to be asymptomatic, and manifests predominately as MPA with renal involvement. Thus, we should remain vigilant to superimposed AAV on RA.


Assuntos
Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos , Artrite Reumatoide , Glomerulonefrite , Poliangiite Microscópica , Vasculite Associada a Anticorpo Anticitoplasma de Neutrófilos/diagnóstico , Anticorpos Anticitoplasma de Neutrófilos , Artrite Reumatoide/complicações , Feminino , Glomerulonefrite/complicações , Humanos , Masculino , Poliangiite Microscópica/complicações , Estudos Retrospectivos
19.
Nanomaterials (Basel) ; 12(7)2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35407277

RESUMO

A magnonic metamaterial in the presence of spatially modulated Dzyaloshinskii-Moriya interaction is theoretically proposed and demonstrated by micromagnetic simulations. By analogy to the fields of photonics, we first establish magnonic Snell's law for spin waves passing through an interface between two media with different dispersion relations due to different Dzyaloshinskii-Moriya interactions. Based on magnonic Snell's law, we find that spin waves can experience total internal reflection. The critical angle of total internal reflection is strongly dependent on the sign and strength of Dzyaloshinskii-Moriya interaction. Furthermore, spin-wave beam fiber and spin-wave lens are designed by utilizing the artificial magnonic metamaterials with inhomogeneous Dzyaloshinskii-Moriya interactions. Our findings open up a rich field of spin waves manipulation for prospective applications in magnonics.

20.
Sensors (Basel) ; 22(7)2022 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-35408344

RESUMO

Polyvinylidene fluoride (PVDF) is a very promising material for fabricating flexible infrared sensors due to its ferroelectricity as well as excellent flexibility and low fabrication cost. This work focuses on improving PVDF's pyroelectric performance by creating microstructures in the film. Simulation results suggest that the pyroelectric response of PVDF film can be improved if micro groove, square-pit or sinusoidal patterns are created on the film surface, with the grooved film showing the best pyroelectric performance. Suggested by the simulation results, flexible PVDF samples with groove structure are prepared by casting the precursor solution on the mold with designed patterns. Measurement results demonstrate that the optimal microstructured PVDF film can improve its pyroelectric performance by as high as 146%, which is in good agreement with the simulations. This work provides an innovative way of achieving flexible infrared sensor devices with promoted performance based on pyroelectric polymers.

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