Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 43
Filter
1.
Curr Issues Mol Biol ; 46(4): 3533-3550, 2024 Apr 18.
Article in English | MEDLINE | ID: mdl-38666951

ABSTRACT

The global spread of SARS-CoV-2 has increased infections among pregnant women. This study aimed to explore placental pathology alterations and angiogenic factor levels in term pregnant women after SARS-CoV-2 infection in a retrospective single-center study. Additionally, we investigated the role and underlying mechanism of the vascular inflammation-promoting, cysteine-rich protein 61 (CYR61/CCN1) in this context. All analyses were performed in term pregnant women infected with or without SARS-CoV-2. The sFlt-1, PlGF, and sEng serum levels were quantified using ELISA. Placental protein expressions were examined by immunoblot and immunostaining. Additionally, the effect of CCN1 protein on SGHPL-5 trophoblast cells was examined. We found that SARS-CoV-2 activated the inflammatory response in pregnant women, leading to pronounced vascular alterations in placental villous tissues. Elevated serum anti-angiogenic factors (sFlt-1, sEng) upon SARS-CoV-2 infection may directly contribute to these pathological changes. Upregulated CCN1 and pNF-κB in placental villous tissues of infected patients are identified as crucial factors in placental alterations. As a conclusion, CCN1 was significantly elevated in the placentas of term pregnant women infected with SARS-CoV-2. By activating a cascade of inflammatory responses, CCN1 induced the production of the anti-angiogenic factors sFlt-1 and sEng, which may lead to abnormal placental vascular architecture.

2.
Drug Resist Updat ; 66: 100907, 2023 01.
Article in English | MEDLINE | ID: mdl-36527888

ABSTRACT

The binding of programmed death-1 (PD-1) on the surface of T cells and PD-1 ligand 1 (PD-L1) on tumor cells can prevent the immune-killing effect of T cells on tumor cells and promote the immune escape of tumor cells. Therefore, immune checkpoint blockade targeting PD-1/PD-L1 is a reliable tumor therapy with remarkable efficacy. However, the main challenges of this therapy are low response rate and acquired resistance, so that the outcomes of this therapy are usually unsatisfactory. This review begins with the description of biological structure of the PD-1/PD-L1 immune checkpoint and its role in a variety of cells. Subsequently, the therapeutic effects of immune checkpoint blockers (PD-1 / PD-L1 inhibitors) in various tumors were introduced and analyzed, and the reasons affecting the function of PD-1/PD-L1 were systematically analyzed. Then, we focused on analyzing, sorting out and introducing the possible underlying mechanisms of primary and acquired resistance to PD-1/PD-L1 blockade including abnormal expression of PD-1/PD-L1 and some factors, immune-related pathways, tumor immune microenvironment, and T cell dysfunction and others. Finally, promising therapeutic strategies to sensitize the resistant patients with PD-1/PD-L1 blockade treatment were described. This review is aimed at providing guidance for the treatment of various tumors, and highlighting the drug resistance mechanisms to offer directions for future tumor treatment and improvement of patient prognosis.


Subject(s)
Drug Resistance, Neoplasm , Neoplasms , Programmed Cell Death 1 Receptor , Humans , B7-H1 Antigen , Drug Resistance , Immunotherapy , Tumor Microenvironment
3.
Ecotoxicol Environ Saf ; 271: 115993, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38271890

ABSTRACT

Bisphenol A (BPA) is one of the environmental endocrine disruptors, due to its chemical stability it exists in abundant concentrations in water and soil consequently accumulating in the food chain and causing many endocrine-related health problems. So far, studies on the effects of BPA on marine invertebrates have focused on acute toxicity, endocrine regulation, reproduction, and development. However, fewer studies have been conducted on marine benthos. The current study aimed to detect the accumulation of BPA and its impact on tissue structure, antioxidant capacity, and immune indexes in marine worm, Urechis unicinctus. U. unicinctus, as a common marine benthic animal, were exposed to different concentrations of BPA. Blood cells and intestinal tract were taken for tissue structure inspection, and supernatant of the coelomic fluid was collected for oxidative and antioxidant biomarkers. Results showed that the accumulation of BPA in muscles of U. unicinctus tended to increase with exposure time. BPA induced a rise in H2O2 and MDA content, and altered the activities of CAT, T-SOD, GST, LSZ and ACP, weaken the immune system functions. Moreover, pathological observation showed that BPA caused severe histopathology in the respiratory intestine, stomach, and midgut. These results will be helpful to understand the response mechanism of U. unicinctus under BPA exposure and provide a reference for controlling the aquaculture conditions and marine water quality of U. unicinctus.


Subject(s)
Antioxidants , Phenols , Polychaeta , Animals , Antioxidants/pharmacology , Hydrogen Peroxide/pharmacology , Benzhydryl Compounds/toxicity
4.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 46(3): 435-443, 2024 Jun.
Article in Zh | MEDLINE | ID: mdl-38953268

ABSTRACT

With the continuous development of identification technologies such as mass spectrometry,omics,and antibody technology,post-translational modification (PTM) has demonstrated increasing potential in medical research.PTM as a novel chemical modification method provides new perspectives for the research on diseases.Succinylation as a novel modification has aroused the interest of more and more researchers.The available studies about succinylation mainly focus on a desuccinylase named sirtuin 5.This enzyme plays a key role in modification and has been preliminarily explored in cardiovascular studies.This paper summarizes the influencing factors and regulatory roles of succinylation and the links between succinylation and other PTMs and reviews the research progress of PTMs in the cardiovascular field,aiming to deepen the understanding about the role of this modification and give new insights to the research in this field.


Subject(s)
Cardiovascular Diseases , Lysine , Protein Processing, Post-Translational , Cardiovascular Diseases/metabolism , Humans , Lysine/metabolism , Succinic Acid/metabolism
5.
Org Biomol Chem ; 21(37): 7597-7601, 2023 Sep 27.
Article in English | MEDLINE | ID: mdl-37676649

ABSTRACT

A mild and efficient synthesis of various aryl sulfonyl fluorides from diaryliodonium salts under organophotocatalysis via a radical sulfur dioxide insertion and fluorination strategy is presented. Diaryliodonium salts are used as aryl radical precursors, the 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO) as a sulfonyl source and cheap KHF2 as a desirable fluorine source, respectively. Notably, the electronic properties of substituents on the aromatic rings in diaryliodonium salts have a significant influence on the reaction yields.

6.
Org Biomol Chem ; 21(18): 3789-3793, 2023 May 10.
Article in English | MEDLINE | ID: mdl-37099401

ABSTRACT

We developed an efficient palladium-catalyzed fluorosulfonylation reaction of aryl thianthrenium salts to smoothly prepare various aryl sulfonyl fluorides using cheap Na2S2O4 as a convenient sulfonyl source in combination with N-fluorobenzenesulfonimide (NFSI) as an ideal fluorine source under mild reduction conditions. A one-pot synthesis of aryl sulfonyl fluorides starting from various arenes was established as well without the need for separating aryl thianthrenium salts. The practicality of this protocol was demonstrated by gram-scale synthesis, derivatization reactions, and excellent yields.

7.
Zhonghua Nan Ke Xue ; 29(4): 331-336, 2023 04.
Article in Zh | MEDLINE | ID: mdl-38598217

ABSTRACT

OBJECTIVE: To study the effect and safety of microscopic varicocele cluster ligation (MVCL). METHODS: We selected 28 patients undergoing bilateral microscopic spermatic vein ligation in Xuzhou Central Hospital from July 2021 to June 2022. Using the computerized randomization method, we performed MVCL or microscopic varicocele ligation (MVL) for the right or the left spermatic cord, respectively. We recorded the operation time, intraoperative blood loss, the numbers of the spermatic veins ligated and the arteries and lymphatic vessels preserved in each surgical side. A surgeon unaware of the surgical approach on the operative side collected the Visual Analogue Scale (VAS) pain scores, nodular foreign body sensation, relief of scrotal cramps, complications, and long-term recurrence from the patients. RESULTS: Compared with the MVL group, the MVCL group showed significantly shorter time for spermatic vein ligation (ï¼»56.21±13.96ï¼½ vs ï¼»31.43±10.13ï¼½ min, P<0.01), lower VAS scores on the 1st postoperative day (P <0.05) and a lower incidence of intra-scrotal nodular foreign body sensation in the 1st postoperative month (P <0.05). There were no statistically significant differences in the intraoperative blood loss, numbers of spermatic veins ligated and arteries and lymphatic vessels preserved, VAS scores at 3 and 7 postoperative days, incidence of complications and long-term recurrence between the two groups (P >0.05). CONCLUSION: MVCL is superior to MVL in reducing the time of spermatic vein ligation and improving the efficiency, efficacy and safety of the procedure, and therefore worthy of clinical promotion.


Subject(s)
Foreign Bodies , Varicocele , Male , Humans , Blood Loss, Surgical , Varicocele/surgery , Veins/surgery , Arteries/surgery
8.
Appl Opt ; 61(14): 4145-4152, 2022 May 10.
Article in English | MEDLINE | ID: mdl-36256091

ABSTRACT

Herein, we studied the increasing tendency of photoacoustic (PA) conversion efficiency of the Au/polydimethylsiloxane (PDMS) composite. The thickness of the Au layer was optimized by modeling the PA process based on the Drude-Lorentz model and finite element analysis method, and corresponding results were verified. The results showed that the optimal Au thickness of the Au/PDMS composite was 35 nm. Finally, the Au/PDMS composites were coated onto the surface of aluminum alloys, which improved the thermoelastic laser ultrasonic (LU) signals to near 100 times. Besides, the defect mapping was performed by thermoelastic LU signals with Au/PDMS coating and ablation LU signals without coating; the Pearson correlation coefficient was higher than 0.95. The application in the defect detection in metal could provide guides for nondestructive detection on metals by laser ultrasound.

9.
Molecules ; 26(19)2021 Sep 22.
Article in English | MEDLINE | ID: mdl-34641272

ABSTRACT

High hydrostatic pressure (HHP) treatment is a non-thermal processing technology, which is widely used in the food processing field at present. In this study, the effects of HHP treatment (100~500 MPa for 5 min) on the physicochemical properties, texture parameters, and volatile flavor compounds of oysters were investigated. The results showed that HHP treatment increased the water content while reducing the crude protein and ash content of the oyster. Texture parameters showed that HHP treatment improved the hardness, springiness, chewiness, and cohesiveness of oysters, compared with the control group. In addition, the saturated fatty acid (SFA) content was slightly increased after HHP treatment, while the difference in monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) content was not significant. Furthermore, HHP increased hexenoic aldehyde, 2,4-heptadienal, 1-octene-3-ol, and 2-octen-1-ol and decreased the contents of 3. 6-nadien-1-ol, 3-octanone, and 2-undecanone, suggesting that HHP might inhibit the fishiness of oyster and showed a positive effect on its flavor. Based on the above results, HHP improved the edible qualities such as texture properties and volatile flavor of oysters. This meets the requirements of consumers on the edible quality of seafood and provides new ideas for the development of seafood.


Subject(s)
Fatty Acids/analysis , Ostreidae/chemistry , Volatile Organic Compounds/isolation & purification , Animals , Food Handling , Food Quality , Hydrostatic Pressure
10.
Acta Pharmacol Sin ; 41(3): 404-414, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31700088

ABSTRACT

Xanthatin is a natural sesquiterpene lactone purified from Xanthium strumarium L., which has shown prominent antitumor activity against a variety of cancer cells. In the current study, we investigated the effect of xanthatin on the growth of glioma cells in vitro and in vivo, and elucidated the underlying mechanisms. In both rat glioma C6 and human glioma U251 cell lines, xanthatin (1-15 µM) dose-dependently inhibited cell viability without apparent effect on the cell cycle. Furthermore, xanthatin treatment dose-dependently induced glioma cell apoptosis. In nude mice bearing C6 glioma tumor xenografts, administration of xanthatin (10, 20, 40 mg·kg-1·d-1, ip, for 2 weeks) dose-dependently inhibited the tumor growth, but did not affect the body weight. More importantly, xanthatin treatment markedly increased the expression levels of the endoplasmic reticulum (ER) stress-related markers in both the glioma cell lines as well as in C6 xenografts, including glucose-regulated protein 78, C/EBP-homologous protein (CHOP), activating factor 4, activating transcription factor 6, spliced X-box binding protein-1, phosphorylated protein kinase R-like endoplasmic reticulum kinase, and phosphorylated eukaryotic initiation factor 2a. Pretreatment of C6 glioma cells with the ER stress inhibitor 4-phenylbutyric acid (4-PBA, 7 mM) or knockdown of CHOP using small interfering RNA significantly attenuated xanthatin-induced cell apoptosis and increase of proapoptotic caspase-3. These results demonstrate that xanthatin induces glioma cell apoptosis and inhibits tumor growth via activating the ER stress-related unfolded protein response pathway involving CHOP induction. Xanthatin may serve as a promising agent in the treatment of human glioma.


Subject(s)
Antineoplastic Agents, Phytogenic/pharmacology , Apoptosis/drug effects , Central Nervous System Neoplasms/drug therapy , Furans/pharmacology , Glioma/drug therapy , Animals , Antineoplastic Agents, Phytogenic/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Cell Cycle/drug effects , Cell Proliferation/drug effects , Cell Survival/drug effects , Central Nervous System Neoplasms/metabolism , Central Nervous System Neoplasms/pathology , Dose-Response Relationship, Drug , Endoplasmic Reticulum Stress/drug effects , Furans/chemistry , Furans/isolation & purification , Glioma/metabolism , Glioma/pathology , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Molecular Structure , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Rats , Structure-Activity Relationship , Tumor Cells, Cultured , Xanthium/chemistry
11.
Appl Opt ; 59(30): 9591-9597, 2020 Oct 20.
Article in English | MEDLINE | ID: mdl-33104681

ABSTRACT

Laser opto-ultrasonic dual (LOUD) detection, which uses laser irradiation of samples to generate spectral and ultrasonic signals simultaneously, can perform multimodal detection of element composition and structural property. As such, it has been applied to the detection of additive manufacturing (AM) components. Further, optimized parameters lead to better detection results. To the best of our knowledge, however, there is no study on the effect of laser properties on LOUD detection. Therefore, we studied the mechanism and influence of laser wavelength and energy on LOUD detection. In this work, the intensity, signal-to-noise ratio (SNR), and stability evolution of the laser excitation spectrum and ultrasonic signals at different wavelengths and energies were analyzed. It was found in the plasma evolution that high electron number density means a large amount of ablated mass generated, which was favorable for laser ultrasonic excitation and can produce higher SNR and a more stable signal. However, it also led to more atoms of the ground-state, which resulted in the self-absorption effect and reduced spectrum intensity in the spectrum analysis. Therefore, with self-absorption correction, better stability, and higher signal intensity, an SNR of spectral and ultrasonic signals can be obtained using 355 nm laser excitation at optimal energy. As a result, in the quantitative analysis of Cu and Si elements by LOUD detection, the determination coefficients (R2) were higher than 0.995, and the average relative errors were less than 2.5%, the limit of detection could reach the order of 100 ppm. Further, the defect size of 0.55 mm in the wire +arc additive manufacturing sample was detected by LOUD detection, and the average relative error was 5.59% compared with the digital radiography results, which indicate that laser wavelength and laser energy affect the intensity and stability of spectral and ultrasonic signals in LOUD detection, which means selecting appropriate laser parameters is important to obtain a high precision detection.

12.
J Neuroinflammation ; 16(1): 35, 2019 Feb 13.
Article in English | MEDLINE | ID: mdl-30760285

ABSTRACT

BACKGROUND: Extracellular accumulation of amyloid ß-peptide (Aß) is one of pathological hallmarks of Alzheimer's disease (AD) and contributes to the neuronal loss. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER) stress-inducible neurotrophic factor. Many groups, including ours, have proved that MANF rescues neuronal loss in several neurological disorders, such as Parkinson's disease and cerebral ischemia. However, whether MANF exerts its protective effect against Aß neurotoxicity in AD remains unknown. METHODS: In the present study, the characteristic expressions of MANF in Aß1-42-treated neuronal cells as well as in the brains of APP/PS1 transgenic mice were analyzed by immunofluorescence staining, qPCR, and Western blot. The effects of MANF overexpression, MANF knockdown, or recombination human MANF protein (rhMANF) on neuron viability, apoptosis, and the expression of ER stress-related proteins following Aß1-42 exposure were also investigated. RESULTS: The results showed the increased expressions of MANF, as well as ER stress markers immunoglobulin-binding protein (BiP) and C/EBP homologous protein (CHOP), in the brains of the APP/PS1 transgenic mice and Aß1-42-treated neuronal cells. MANF overexpression or rhMANF treatment partially protected against Aß1-42-induced neuronal cell death, associated with marked decrease of cleaved caspase-3, whereas MANF knockdown with siRNA aggravated Aß1-42 cytotoxicity including caspase-3 activation. Further study demonstrated that the expressions of BiP, ATF6, phosphorylated-IRE1, XBP1s, phosphorylated-eIF2α, ATF4, and CHOP were significantly downregulated by MANF overexpression or rhMANF treatment in neuronal cells following Aß1-42 exposure, whereas knockdown of MANF has the opposite effect. CONCLUSIONS: These findings demonstrate that MANF may exert neuroprotective effects against Aß-induced neurotoxicity through attenuating ER stress, suggesting that an applicability of MANF as a therapeutic candidate for AD.


Subject(s)
Amyloid beta-Peptides/toxicity , Apoptosis/drug effects , Endoplasmic Reticulum Stress/drug effects , Nerve Growth Factors/metabolism , Nerve Growth Factors/therapeutic use , Neurons/drug effects , Peptide Fragments/toxicity , Up-Regulation/drug effects , Amyloid beta-Protein Precursor/genetics , Amyloid beta-Protein Precursor/metabolism , Animals , Brain/drug effects , Brain/metabolism , Cells, Cultured , Cerebral Cortex/cytology , Embryo, Mammalian , Humans , Mice , Mice, Inbred C57BL , Mice, Transgenic , Nerve Growth Factors/genetics , Neuroblastoma/pathology , Phosphopyruvate Hydratase/metabolism , Presenilin-1/genetics , Presenilin-1/metabolism , RNA, Small Interfering/pharmacology , RNA, Small Interfering/therapeutic use
13.
Opt Express ; 27(10): 15091-15099, 2019 May 13.
Article in English | MEDLINE | ID: mdl-31163946

ABSTRACT

Heavy metal pollution is one of the main problems in water pollution, which is harmful to humans. Surface-enhanced laser-induced breakdown spectroscopy (SENLIBS) has been applied to detect trace amounts of heavy metal elements in aqueous solution; however, it is still a big challenge to explore the relationship between the LIBS detection sensitivity and the substrate's physical properties. In this work, four typical substrates, zinc (Zn), magnesium alloy (Mg), nickel (Ni), and silicon (Si), were compared; and the mechanism of spectral enhancement by different substrates in SENLIBS was investigated. The results indicated that the limit of detection (LoD) of heavy metal elements on different substrates is positively proportional to the boiling of the substrate. That is mainly because a higher plasma excitation temperature and electron density are obtained, leading to more intense collision between particles. The signal enhancement is associated with the lower boiling point of the substrate (corresponding to a lower ablation threshold and higher ablation quantity from the substrate). As a result, the best LoD was 0.0011 mg/L for chromium (Cr) and 0.004 mg/L for lead (Pb) on an optimal Zn substrate, respectively. The LoDs were sufficiently low to meet the drinking water sanitation standard. These results showed that the detection sensitivity of heavy metal elements in aqueous solution can be improved by choosing a substrate with a lower boiling point in SENLIBS.

14.
Opt Express ; 27(4): 4261-4270, 2019 Feb 18.
Article in English | MEDLINE | ID: mdl-30876043

ABSTRACT

Self-absorption seriously affects the accuracy and stability of quantitative analysis in laser-induced breakdown spectroscopy (LIBS). To reduce the effect of self-absorption, we investigated the temporal evolution of the self-absorption effect by establishing exponential calibration curves. Meanwhile, the temporal evolution mechanism of the self-absorption effect was also investigated. The results indicated that self-absorption was weak at the early stage of plasma expansion. For determination of manganese (Mn) in steel, as an example, the concentration of upper bound of linearity (Cint) was 2.000 wt. % at the early stage of plasma expansion (in a time window of 0.2-0.4 µs)-much higher than 0.363 wt. % at a traditional optimization time window (2-3 µs). The accuracy and stability of quantitative analysis at the time window of 0.2-0.4 µs was also much better than at the time window of 2-3 µs. This work provides a simple method for improving quantitative analysis performance and avoiding the self-absorption effect in LIBS.

15.
BMC Public Health ; 19(1): 1279, 2019 Oct 07.
Article in English | MEDLINE | ID: mdl-31590643

ABSTRACT

BACKGROUND: Studies from Western countries reported a positive relationship between residential density (RD) and physical activity (PA) among adults. There was no such study from China, a rapidly-urbanizing country in the world. This study aimed to investigate the RD-PA association among urban adults in China. METHODS: A multistage sampling approach was used to randomly select participants (aged 35-74 years old) in urban areas of Nanjing in 2017. The outcome variable was PA (dichotomized into "sufficient" or "insufficient"), while the independent variable was RD (tertiled into three sub-groups). Odds ratios (OR) and 95% confidence interval (CI) were computed to examine the RD-PA association using mixed-effects logistic regression models with adjustment for age, sex, nationality, marriage, educational attainment, employment status, body weight status, green space and neighborhood-level clustering effects. RESULTS: Of the 1568 eligible participants, 1551 were interviewed (response rate = 98.9%), with the mean age (standard deviation) of 54.7 (11.1) years old, and 46% of men. After adjustment for potential confounders and community-level clustering effects, participants lived in communities with higher (OR = 0.31, 95% CI = 0.21, 0.47) and middle (OR = 0.70, 95% CI = 0.50, 0.99) residential density were significantly less likely to achieve sufficient physical activity relative to their counterparts lived in the lower densed communities. Similar negative RD-PA association was examined for men or women, separately. The difference in the ORs between the middle and higher RD tertiles was also statistically significant (P < 0.01). CONCLUSIONS: A negatively gradient RD-PA association, independent of body weight status and green space, was observed among urban adults in regional China. It has public health implications for China to help residents' promote and maintain physical activity through planning and constructing PA-/health-friendly built environment in future.


Subject(s)
Exercise , Population Density , Residence Characteristics/statistics & numerical data , Urban Population/statistics & numerical data , Adult , Aged , China , Female , Humans , Male , Middle Aged
16.
J Sci Food Agric ; 99(12): 5558-5564, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31150114

ABSTRACT

BACKGROUND: Rice adulteration in the food industry that infringes on the interests of consumers is considered very serious. To realize the rapid and precise quantitation of adulterated rice, a visible near infrared (VNIR) hyperspectral imaging system (380-1000 nm) was developed in the present study. A Savitsky-Golay first derivative (SG1) transform was utilized to eliminate the constant spectral baseline offset. Then, the adulterated levels of rice samples were quantified by partial least squares regression (PLSR). RESULTS: A SG1-PLSR model based on full-wavelength was attained with a coefficient of determination of prediction set (RP ) of 0.9909, root-mean-square error of prediction set (RMSEP ) of 0.0447 g kg-1 and residual predictive deviation (RPDP ) of 11.28. Furthermore, fifteen important wavelengths were selected based on the weighted regression coefficients (BW ) and a simplified model (PLSR-15) was established with RP of 0.9769, RMSEP of 0.0708 g kg-1 and RPDP of 3.49. Finally, two visualization maps produced by applying the optimal models (SG1-PLSR and PLSR-15) were used to visualize the adulterated levels of rice. CONCLUSION: These results demonstrate that VNIR hyperspectral imaging system is an effective tool for rapidly quantifying and visualizing the adulterated levels of rice. © 2019 Society of Chemical Industry.


Subject(s)
Oryza/chemistry , Spectroscopy, Near-Infrared/methods , Food Contamination/analysis , Least-Squares Analysis
17.
Opt Express ; 26(23): 30409-30419, 2018 Nov 12.
Article in English | MEDLINE | ID: mdl-30469915

ABSTRACT

Fiber-optic laser-induced breakdown spectroscopy (FO-LIBS) has been employed in many applications because of the flexibility of optical fiber cable. However, the inhomogeneous elemental distribution of plasmas can cause a self-absorption effect and, hence, significantly hinder the determination of FO-LIBS. Here, to solve this flaw, we took iron (Fe), magnesium (Mg), and zinc (Zn) elements in aluminum alloy as examples to investigate the self-absorption reduction and accuracy improvement using spatially resolved FO-LIBS. Spatially resolved FO-LIBS means the spectra were collected at different positions along the direction parallel to the surface of the sample rather than at the center of the plasma. With this method, the self-absorption effect could be improved by selecting different acquisition positions along the X-axis. The root mean square error of cross-validations (RMSECV) for Fe, Mg, and Zn were reduced from 0.388, 0.348, and 0.097 wt. % to 0.172, 0.224, and 0.024 wt. %, respectively. Generally, spatial resolution is an effective method of self-absorption reduction and accuracy improvement in FO-LIBS.

18.
Chemistry ; 24(45): 11755-11762, 2018 Aug 09.
Article in English | MEDLINE | ID: mdl-29790220

ABSTRACT

Three novel 9,10-dihydroacridine derivatives, 4'-(10-methyl-9,9-diphenyl-9,10-dihydroacridin-4-yl)[1,1'-biphenyl]-4-carbonitrile (MeAcPhCN), 4'-(9,9,10-triphenyl-9,10-dihydroacridin-4-yl)[1,1'-biphenyl]-4-carbonitrile (PhAcPhCN), and 5-[4-(9,9,10-triphenyl-9,10-dihydroacridin-4-yl)phenyl]picolinonitrile (MeAcPyCN), were prepared by the attachment of [1,1'-biphenyl]-4-carbonitrile or 5-phenylpicolinonitrile to the 4-position of 9,10-dihydroacridine. This special linking strategy limited the conjugation length, maintained the triplet energy, and inhibited the intermolecular charge-transfer (ICT) characteristics of these compounds. Notably, the enhanced accepting strength of the picolinonitrile segment relative to that of benzonitrile led to relatively strong ICT characteristics, a low energy gap, and a low triplet energy for MeAcPyCN. The thermal, photophysical, electrochemical, and electroluminescent properties of these host materials were studied systematically. Consequently, (acetylacetonato)bis(2-methyldibenzo[f,h]quinoxaline)iridium(III) [Ir(MDQ)2 (acac)]-based red phosphorescent organic light-emitting diodes (PHOLEDs) were fabricated with these three host materials. As a result, the device hosted by MeAcPhCN showed good device performance with a maximum external quantum efficiency of 20.5 %.

19.
Nanomaterials (Basel) ; 14(8)2024 Apr 20.
Article in English | MEDLINE | ID: mdl-38668216

ABSTRACT

Compared to SnTe and PbTe base materials, the GeTe matrix exhibits a relatively high Seebeck coefficient and power factor but has garnered significant attention due to its poor thermal transport performance and environmental characteristics. As a typical p-type IV-VI group thermoelectric material, W-doped GeTe material can bring additional enhancement to thermoelectric performance. In this study, the introduction of W, Ge1-xWxTe (x = 0, 0.002, 0.005, 0.007, 0.01, 0.03) resulted in the presence of high-valence state atoms, providing additional charge carriers, thereby elevating the material's power factor to a maximum PFpeak of approximately 43 µW cm-1 K-2, while slightly optimizing the Seebeck coefficient of the solid solution. Moreover, W doping can induce defects and promote slight rhombohedral distortion in the crystal structure of GeTe, further reducing the lattice thermal conductivity κlat to as low as approximately 0.14 W m-1 K-1 (x = 0.002 at 673 K), optimizing it to approximately 85% compared to the GeTe matrix. This led to the formation of a p-type multicomponent composite thermoelectric material with ultra-low thermal conductivity. Ultimately, W doping achieves the comprehensive enhancement of the thermoelectric performance of GeTe base materials, with the peak ZT value of sample Ge0.995W0.005Te reaching approximately 0.99 at 673 K, and the average ZT optimized to 0.76 in the high-temperature range of 573-723 K, representing an increase of approximately 17% compared to pristine GeTe within the same temperature range.

20.
J Mater Chem B ; 12(9): 2217-2235, 2024 Feb 28.
Article in English | MEDLINE | ID: mdl-38345580

ABSTRACT

During the process of peripheral nerve repair, there are many complex pathological and physiological changes, including multi-cellular responses and various signaling molecules, and all these events establish a dynamic microenvironment for axon repair, regeneration, and target tissue/organ reinnervation. The immune system plays an indispensable role in the process of nerve repair and function recovery. An effective immune response not only involves innate-immune and adaptive-immune cells but also consists of chemokines and cytokines released by these immune cells. The elucidation of the orchestrated interplay of immune cells with nerve regeneration and functional restoration is meaningful for the exploration of therapeutic strategies. This review mainly enumerates the general immune cell response to peripheral nerve injury and focuses on their contributions to functional recovery. The tissue engineering-mediated strategies to regulate macrophages and T cells through physical and biochemical factors combined with scaffolds are discussed. The dynamic immune responses during peripheral nerve repair and immune-cell-mediated tissue engineering methods are presented, which provide a new insight and inspiration for immunomodulatory therapies in peripheral nerve regeneration.


Subject(s)
Peripheral Nerve Injuries , Humans , Peripheral Nerve Injuries/therapy , Tissue Engineering , Peripheral Nerves , Nerve Regeneration , Macrophages
SELECTION OF CITATIONS
SEARCH DETAIL