Publications by authors named "Hua Li"

2,872 Publications

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Targeting both BDNF/TrkB pathway and delta-secretase for treating Alzheimer's disease.

Neuropharmacology 2021 Jul 31:108737. Epub 2021 Jul 31.

Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA. Electronic address:

Alzheimer's disease (AD) is the most common dementia, and no disease-modifying therapeutic agents are currently available. BDNF/TrkB signaling is impaired in AD and is associated with prominent delta-secretase (δ-secretase, also known as asparaginyl endopeptidase or legumain) activation, which simultaneously cleaves both APP and Tau and promotes Aβ production and neurofibrillary tangles (NFT) pathologies. Here we show that the optimized δ-secretase inhibitor (#11a) or TrkB receptor agonist (CF3CN) robustly blocks δ-secretase activity separately, and their combination synergistically blunts δ-secretase, exhibiting promising therapeutic efficacy in 3xTg AD mouse model. The optimal δ-secretase inhibitor reveals demonstrable brain exposure and oral bioavailability, suppressing APP N585 and Tau N368 cleavage by δ-secretase. Strikingly, CF3CN treatment evidently escalates BDNF levels. Both #11a and CF3CN display strong in vivo PK/PD properties and ability to suppress δ-secretase activity in the brain. Orally administrated CF3CN strongly activates TrkB that triggers active Akt to phosphorylate δ-secretase T322, preventing its proteolytic activation and mitigating AD pathologies. #11a or CF3CN significantly diminishes AD pathogenesis and improves cognitive functions with the combination exhibiting the maximal effect. Thus, our data support that these derivatives are strong pharmaceutical candidates for the treatment of AD.
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http://dx.doi.org/10.1016/j.neuropharm.2021.108737DOI Listing
July 2021

Effect of Dexmedetomidine on Perioperative Hemodynamics and Myocardial Protection in Thoracoscopic-Assisted Thoracic Surgery.

Med Sci Monit 2021 Aug 3;27:e929949. Epub 2021 Aug 3.

Department of Anesthesiology, Shanghai Pulmonary Hospital, Shanghai, China (mainland).

BACKGROUND This study aimed to clarify the protective role of dexmedetomidine in thoracoscopic-assisted thoracic surgery (TATS), including control of the intraoperative heart rate, blood pressure, and myocardial injury markers. MATERIAL AND METHODS The patients who underwent TATS were divided into 2 equal groups: the dexmedetomidine group (dexmedetomidine pumped at 0.5 µg/kg for >10 min before the administration of anesthesia and at 0.5 µg/kg in the maintenance period) and the control group (pumped normal saline for >10 min before the administration of anesthesia). The data recorded for each patient were heart rate (preoperative, maximum intraoperative, and minimum intraoperative), systolic and diastolic blood pressure, intraoperative hemodynamic data, and intraoperative cardiovascular drugs administered. An enzyme-linked immunosorbent assay was performed to assess the postoperative levels of cardiac troponin I (cTnI), creatine kinase isoenzyme, myoglobin, and N-terminal pro-B-type natriuretic peptide (NT-proBNP). RESULTS There were no significant differences in the age, sex, body height, body weight, American Society of Anesthesiologists classification grade, resection mode, operation time, ejection fraction, basal heart rate, and systolic and diastolic blood pressure of the 2 groups. In the dexmedetomidine group, the patients' maximum intraoperative heart rate and diastolic pressure decreased, and the postoperative hospital stay period was shorter. The postoperative peripheral blood test for the dexmedetomidine group showed higher NT-proBNP levels and lower cTnI levels. CONCLUSIONS Preoperative administration of dexmedetomidine can benefit hemodynamic stability, protect the cardiovascular system in the intraoperative and postoperative periods, and shorten postoperative hospitalization.
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http://dx.doi.org/10.12659/MSM.929949DOI Listing
August 2021

A natural DYRK1A inhibitor as a potential stimulator for β-cell proliferation in diabetes.

Clin Transl Med 2021 Jul;11(7):e494

Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, China.

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http://dx.doi.org/10.1002/ctm2.494DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8288015PMC
July 2021

Amphetamine Drug Detection with Inorganic MgO Nanotube Based on the DFT Calculations.

Appl Biochem Biotechnol 2021 Jul 26. Epub 2021 Jul 26.

Department of Chemistry, Faculty of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran.

In this study, the main challenge was to focus on the detection of amphetamine (AN) using a type of magnesium oxide nanotube (MgONT) sensor through density functional theory (DFT) calculations. Nowadays, due to the adverse effects of drug abuse, governments put all their efforts into detecting and managing illegal drugs such as AN. Therefore, the detection of AN in biological specimens is of great importance. In this study, through DFT calculations, the intrinsic sensing properties of MgONT were investigated for the detection of AN. We concluded that the MgONT considerably enhances the reactivity of the MgONT toward AN. Furthermore, the sensing response for the MgONT was 392.36. The results showed that there was a considerable change in the energy levels of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and there was a drop in the band gap value (E). This decrease in the E value improved the electrical conductivity. Moreover, desorption of AN from the surface of the MgONT had a slight recovery time (~ 22.89 ms). This work illustrated that MgONT could be considered a proper candidate for electronic sensing and AN drug delivery in biological systems.
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http://dx.doi.org/10.1007/s12010-021-03633-6DOI Listing
July 2021

The association between ECG criteria and Echo criteria for left ventricular hypertrophy in a general Chinese population.

Ann Noninvasive Electrocardiol 2021 Jul 26:e12880. Epub 2021 Jul 26.

Department of Cardiology, Tsinghua University, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Beijing, China.

Background: Several ECG criteria have been widely used for diagnosis of left ventricular hypertrophy (LVH) in clinical practice. However, their performance in a general Chinese population is limited.

Methods And Results: A multi-stage, stratified cluster sampling across China was performed and 7415 representative Chinese adults aged 18-85 years were analyzed. ECG was collected by using GE MAC 5500 machine. The association between five ECG-LVH criteria (i.e., Peguero-Lo Presti, Cornell, Cornell product, Sokolow-Lyon and Sokolow-Lyon product) and echocardiographic LVH (Echo-LVH) was assessed by Pearson's correlation, diagnostic statistics like predictive values, and receiver operating characteristics (ROC) curve. We found that the prevalence of the Echo-LVH was 11% while ECG-LVH ranged from 3% to 27%. All ECG-LVH criteria had high negative predictive value (NPV) (89%) and specificity (73-96%) but low positive predictive value (PPV) (12-24%) and sensitivity (4-29%). The newly Peguero-Lo Presti criteria had higher sensitivity (29%) but lower specificity (73%) and accuracy (68%) compared with other criteria. Cornell product had the best diagnostic performance (AUC: 0.59), as well as the highest specificity (96%) and accuracy (86%) but lowest sensitivity (4%). Among single-lead components of ECG criteria, R voltage and QRS duration performed relatively better than others. Hypertensive and older individuals had higher sensitivity but lower specificity and accuracy than their counterparts.

Conclusion: ECG-LVH criteria had high NPV to detect Echo-LVH. Though with higher sensitivity, Peguero-Lo Presti criteria did not have better diagnostic performance to detect Echo-LVH. R and QRS duration had stronger association with Echo-LVH among all single-lead components.
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http://dx.doi.org/10.1111/anec.12880DOI Listing
July 2021

Automatic detection of interictal ripples on scalp EEG to evaluate the effect and prognosis of ACTH therapy in patients with infantile spasms.

Epilepsia 2021 Jul 26. Epub 2021 Jul 26.

Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China.

Objective: We aimed to explore the feasibility of using scalp-recorded high-frequency oscillations (HFOs) to evaluate the efficacy and prognosis of adrenocorticotropic hormone (ACTH) treatment in patients with infantile spasms.

Methods: Thirty-nine children with infantile spasms were enrolled and divided into seizure-free and non-seizure-free groups after ACTH treatment. Patients who were seizure-free were further divided into relapse and non-relapse subgroups based on the observations made during a 6-month follow-up period. Scalp ripples were detected and compared during the interictal periods before and after 2 weeks of treatment.

Results: After ACTH treatment, the number and channels of ripples were significantly lower, whereas the percentage decrease in the number, spectral power, and channels of ripples was significantly higher in the seizure-free group than in the non-seizure-free group. In addition, the relapse subgroup showed higher number and spectral power and wider distribution of ripples than did the non-relapse subgroup. Changes in HFOs in terms of number, spectral power, and channel of ripples were closely related to the severity of epilepsy and can indicate disease susceptibility.

Significance: Scalp HFOs can be used as an effective biomarker to monitor the effect and evaluate the prognosis of ACTH therapy in patients with infantile spasms.
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http://dx.doi.org/10.1111/epi.17018DOI Listing
July 2021

[Distribution and Sources of Microplastics in Farmland Soil Along the Fenhe River].

Huan Jing Ke Xue 2021 Aug;42(8):3894-3903

Shanxi Laboratory for Yellow River, School of Environment and Resources, Shanxi University, Taiyuan 030006, China.

This study investigated the distribution and sources of microplastics smaller than 1 mm in farmland soil along the Fenhe River. Microplastics in soil samples were separated and extracted using the traditional density centrifugation method. The quantity and type of microplastics were examined with a stereomicroscope. The micro-morphology of plastic particles were observed with a scanning electron microscope-energy dispersive spectrometer. The chemical composition was determined using Fourier transform infrared spectroscopy. The results indicate that the average abundance of microplastics in farmland soil along the Fenhe River is 290.5 n ·kg. These microplastics occur as fibers, films, fragments, and foams. Fiber microplastics are the most abundant, accounting for 52.67% of the total, and are mostly composed of polyethylene. Films and fragments mainly consist of polypropylene whereas the foams consist of polystyrene. Soil samples from different parts of the Fenhe River can be ranked according to the microplastics content in the following order:downstream>midstream>upstream. The abundance of microplastics in soil from the downstream region of the Fenhe River was 500.0 n ·kg, twice that of from the upstream and midstream regions. The results of the random forest model indicate that the sources of microplastics in farmland soil along the Fenhe River are closely related to the amount of agricultural films, population, gross domestic product, and industrial production. Among these factors, the amount of agricultural films is a key factor that influences the occurrence of microplastics in farmland soil along the Fenhe River.
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http://dx.doi.org/10.13227/j.hjkx.202012072DOI Listing
August 2021

Cell-penetrating heme oxygenase-1 in the therapy of atopic dermatitis in mice.

Exp Ther Med 2021 Sep 1;22(3):941. Epub 2021 Jul 1.

School of Medicine, Huzhou University, Huzhou, Zhejiang 313000, P.R. China.

Atopic dermatitis (AD), also referred to as atopic eczema, is a long-term inflammatory condition that is characterized by itchy, red, swollen and cracked skin. Accumulating evidence suggests that AD is caused by genetic factors, environmental exposure and immune system dysfunction; however, its underlying molecular mechanism remains unclear. Current treatment strategies aim to decrease the severity and frequency of flares. Heme oxygenase-1 (HO-1) is a nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated gene that plays crucial roles against stress, inflammation and oxidation, and exerts cytoprotective effects. Previous studies have reported that treatment of AD induces high expression levels of HO-1 and Nrf2, indicating that HO-1 may play an important role in the treatment of AD. The present study constructed the recombinant protein, cell-penetrating peptide-HO-1 (CPP-HO-1), which was expressed in and isolated with a 6xHis-tag using HiTrap His column (1 ml). AD was established using 4-dinitrochlorobenzene (DNCB) in mice. It was observed that the CPP-HO-1 fusion protein decreased the severity of AD, inhibited scratching in mice and decreased skin inflammation. Taken together, the results of the present study suggested that the CPP-HO-1 fusion protein may play a protective role against DNCB-induced AD in mice.
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http://dx.doi.org/10.3892/etm.2021.10373DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8281355PMC
September 2021

Visualization of gaseous iodine adsorption on single zeolitic imidazolate framework-90 particles.

Nat Commun 2021 07 23;12(1):4483. Epub 2021 Jul 23.

National Collaborative Innovation Center for Nuclear Waste and Environmental Safety, School of National Defence Science & Technology, Southwest University of Science and Technology, Mianyang, PR China.

Zeolitic imidazolate frameworks (ZIFs) are very useful as high-capacity iodine (I) adsorbents. The adsorption performance is usually probed by measuring a statistical average property over an entire sample consisting of a large number of ZIF particles, leaving the interparticle heterogeneity information among individuals. Here we report a dark-field microscopy (DFM) method to visualize gaseous I adsorption on single ZIF-90 particles in situ and in real time. The adsorption of I is found to alter the scattering spectrum of ZIF-90 particles, inducing a distinct color change from bluewhite to yellow. According to correlating the adsorption amount of gaseous I with the change of B value from DFM images, we quantitatively image the adsorption process and estimate the related kinetic parameters at the single particle level. Single particle measurements clarify the large particle-to-particle heterogeneity in adsorption reactivity and significant adsorption activity improvement of ZIF-90 after introduction of linker defects, which provides a microscopic understanding of the structure-activity relationship. We further demonstrate the capacity of this strategy for studying gaseous I adsorption on single ZIF-91 particle as a derivative of ZIF-90 to illustrate the generality.
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http://dx.doi.org/10.1038/s41467-021-24830-1DOI Listing
July 2021

Study on the mechanism of the Modified Ginseng-Schisandra Decoction (MGSD) in the treatment of recurrent respiratory tract infection (RRTI) based on network pharmacology.

Transl Pediatr 2021 Jun;10(6):1701-1711

Jilin Province Jilin Hospital of Integrated Chinese and Western Medicine, Jilin, China.

Background: The aim of this study was to investigate the mechanism of Modified Ginseng-Schisandra Decoction in the treatment of recurrent respiratory tract infection (RRTI) using network pharmacology.

Methods: To screen the active ingredients of A Modified Ginseng-Schisandra Decoction, TCMSP, TCMID, Batman-TCM and PubChem database were applied. To predict the targets of active ingredients on RRTI, TCMSP, Pubmed, OMIM, Drug Bank, GAD and TTD database were used. The compounds-therapeutic target network was constructed with Cytoscape 3.7.2 software. The STRING database was used to construct a protein-protein interaction (PPI) network, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis was used to identify potential signal pathways.

Results: The 3 main active ingredients of Modified Ginseng-Schisandra Decoction obtained by screening were quercetin, kaempferol, and isoflavone; the main therapeutic targets were , and others. Based on the PPI network, we found that the targets of Modified Ginseng-Schisandra Decoction were significantly enriched in (FDR <0.01) cancer pathway, tumor necrosis factor (TNF) signaling pathway, hypoxia-inducible factor (HIF-1) signaling pathway, and others.

Conclusions: Modified Ginseng-Schisandra Decoction can treat RRTI primarily through acting in the signal transduction of some key nodes of cancer pathway and TNF pathway. It exerts a direct or indirect influence on multiple signaling pathways, and has the characteristics of multicomponent, multitarget, and multichannel action.
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http://dx.doi.org/10.21037/tp-21-240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261594PMC
June 2021

Clinical observation of the effect of modified Ginseng-Schisandra decoction (MGSD) on trace elements and immune function in children with spleen deficiency syndrome after recurrent respiratory tract infection (RRTI): a randomized controlled trial.

Transl Pediatr 2021 Jun;10(6):1692-1700

Shanghai University of Traditional Chinese Medicine, Shanghai, China.

Background: Recurrent respiratory tract infection (RRTI) is common disease in childhood, and the incidence rate is increasing in China. The cause is complex, which is related to the physiological characteristics of children's respiratory system and the immature immune function, lack of trace elements and environmental pollution. Immunomodulators and antibiotics are often used to treat RRTI, but the clinical efficacy still needs to be improved. Chinese medicine has unique advantages in the treatment of RRTI. In the clinical treatment of RRTI, the authors often use modified Ginseng-Schisandra decoction (MGSD). In order to study the clinical effect of MGSD on serum trace elements and immune function in children with spleen deficiency syndrome after RRTI, we conducted this clinical observation.

Methods: This is a single-center randomized trial with two parallel groups. Eighty children who developed spleen deficiency syndrome following RRTI were randomly and equally divided into a control group and an observation group. The control group was given Medilac-vita and the observation group was given MGSD. The participants, care givers, and those assessing the outcomes were blinded to group assignment. The treatment course was 4 weeks. Clinical efficacy, traditional Chinese medicine (TCM) syndrome scores, humoral immunity, and trace element index values before and after treatment were compared between the two groups of children.

Results: The trial was finished. The total effective rate of the observation group (n=40, 95%) was significantly higher than control group (n=40, 65%) (P<0.05). After treatment, the TCM syndrome scores of the two groups were reduced compared to those before treatment, while the serum immunoglobulin A and G levels were increased (P<0.05); however, the observation group had significantly lower TCM syndrome scores than the control group. Significant improvements in serum immunoglobulins (IgA and IgG) levels, T lymphocyte subsets (CD3, CD4, and CD4/CD8), and trace elements (Zn and Fe) indicators were observed in the observation group compared to the control group (P<0.05).

Conclusions: The application of MGSD in the treatment of children with spleen deficiency syndrome after RRTI has a definite clinical effect. MGSD can effectively improve the immune function of the patients and the content of the trace elements iron and zinc, and thus has potential value for promotion and application.

Trial Registration: Chinese Clinical Trial Registry ChiCTR2100047128.
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http://dx.doi.org/10.21037/tp-21-243DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8261592PMC
June 2021

Effects of Heat Stress on Gut Microbiome in Rats.

Indian J Microbiol 2021 Sep 29;61(3):338-347. Epub 2021 May 29.

College of Veterinary Medicine, South China Agricultural University, Guangzhou, 510642 People's Republic of China.

Gut microbiome, as the largest and most important micro-ecosystem, plays a critical role in health. The purpose of this study was to evaluate whether heat stress modulates the composition and diversity of the gut microbiome in rats. The heat stress model was prepared in rats with the heating temperature maintained at 35-38°C. Cecum contents were collected after heat stress for 3 h and days 1, 3 and 7. Total DNA was extracted for 16 S rRNA sequencing and analysis of intestinal microbiome composition and diversity. The study showed that the composition of the intestinal microbiome of heat stress group was changed. And the heat stress modulated key phylotypes of gut microbiota at the level of phylum and genus. In particular, the genus of and were significantly reduced, whereas the and were increased by heat stress. Meanwhile, the rats under the heat stress encountered the change in carbohydrate metabolism, amino acid metabolism, and membrane transport to defense against stress. Taken together, the composition and structure of gut microbiome were affected by heat stress and some key phylotypes were also significantly altered. We conclude that the heat stress could impact multiple biological functions, via altering the gut microbiome.
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http://dx.doi.org/10.1007/s12088-021-00948-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8263838PMC
September 2021

FUT11 is a target gene of HIF1α that promotes the progression of hepatocellular carcinoma.

Cell Biol Int 2021 Jul 21. Epub 2021 Jul 21.

Department of Orthopedics, Guiyang Maternal and Child Health-care Hospital, Guiyang, Guizhou, China.

Hypoxia promotes the progression of hepatocellular carcinoma. However, the hypoxia regulatory network in hepatocellular carcinoma is known to be limited. Thus, this study aimed to identify the crucial hypoxia-associated genes and to explore their effects and molecular mechanisms in hepatocellular carcinoma cells. FUT11 was first identified as a crucial hypoxia-associated gene through bioinformatics analysis. High FUT11 mRNA levels were positively correlated with poor clinical parameters. FUT11 knockdown under normoxia and hypoxia both decreased hepatocellular carcinoma cell proliferation, colony formation, migration, and invasion. HIF1α binds to the promoter of FUT11 and increases its transcription and co-expression with FUT11 in hepatocellular carcinoma tissues. Overexpression of FUT11 in HIF1α knockdown cells reversed the inhibitory effects of HIF1α suppression on hepatocellular carcinoma cell proliferation and mobility under hypoxia. Therefore, our findings indicate that FUT11 is a key target gene of HIF1α, which can promote the proliferation and mobility of hepatocellular carcinoma cells. FUT11 may be a novel and effective target for blocking the hypoxia response of hepatocellular carcinoma cells.
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http://dx.doi.org/10.1002/cbin.11675DOI Listing
July 2021

Predisposition to Graves' disease and Graves' ophthalmopathy by genetic variants of IL2RA.

J Mol Med (Berl) 2021 Jul 21. Epub 2021 Jul 21.

School of Basic Medical Science, Special Key Laboratory of Ocular Diseases of Guizhou Province, Zunyi Medical University, Zunyi, 563000, China.

Previous studies have identified that Th17/Treg cells were involved in the occurrence and development of Graves' disease (GD). This study aimed at clarifying the association between GD susceptibility and nine single nucleotide polymorphisms (SNPs) of Th17/Treg cell-related genes, including IL2RA, miR27a, miR182, and FoxO1. A two-stage association study was performed in 650 GD patients and 1300 healthy controls. PCR-RFLP assays, real-time PCR, and ELISA were performed. In the first stage, association analysis has identified that IL2RA/rs3118470 TT genotype (Pc = 0.027, OR = 1.688) and IL2RA/rs2104286 AA genotype (Pc = 0.027, OR = 1.658) has significantly increased frequencies in patients with GD than control subjects. In the second stage, the result of rs2104286 was consistent with the first-stage results (AA genotype: Pc = 0.006, OR = 1.618). The combined data showed that IL2RA/rs2104286 AA genotype had increased frequencies in patients with GD (Pc = 8.772 × 10, OR = 1.636). Stratification analysis also revealed that rs2104286 AA genotype was significantly associated with Graves' ophthalmopathy (GO) susceptibility (Pc = 9.150 × 10, OR = 1.851). Functional studies showed that carriers of the rs2104286 AA genotype had lower IL2RA mRNA expression than AG genotype carriers (P = 0.021). Cytokine analyses revealed that the rs2104286 AA genotype individuals had lower IL-10 levels (P = 0.015) and increased IL-17 levels than AG genotype carriers (P = 1.467 × 10). In conclusion, our findings suggested that IL2RA/rs2104286 was associated with GD and GO susceptibility in Southwest Chinese Han population, which may be involved in the occurrence of GD and GO by affecting the mRNA expression of IL2RA gene and the cytokine production. KEY MESSAGES: We identified that IL2RA/rs2104286 locus contributed to the predisposition of Graves' disease (GD) and Graves' ophthalmopathy (GO). Functional analyses suggested that IL2RA/rs2104286 may participate in the occurrence of GD and GO by affecting the mRNA expression of IL2RA and cytokine (IL-10 and IL-17) secretion. We found that IL2RA (rs3118470, rs7093069), miR27a/rs895819, miR182/rs76481776, and FoxO1 (rs2297626, rs17592236, rs9549241, rs12585277) loci polymorphisms were not associated with GD susceptibility.
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http://dx.doi.org/10.1007/s00109-021-02111-0DOI Listing
July 2021

Discovery of metal-based complexes as promising antimicrobial agents.

Eur J Med Chem 2021 Jul 8;224:113696. Epub 2021 Jul 8.

Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, China. Electronic address:

The antimicrobial resistance (AMR) is an intractable problem for the world. Metal ions are essential for the cell process and biological function in microorganisms. Many metal-based complexes with the potential for releasing ions are more likely to be absorbed for their higher lipid solubility. Hence, this review highlights the clinical potential of organometallic compounds for the treatment of infections caused by bacteria or fungi in recent five years. The common scaffolds, including antimicrobial peptides, N-heterocyclic carbenes, Schiff bases, photosensitive-grand-cycle skeleton structures, aliphatic amines-based ligands, and special metal-based complexes are summarized here. We also discuss their therapeutic targets and the risks that should be paid attention to in the future studies, aiming to provide information for researchers on metal-based complexes as antimicrobial agents and inspire the design and synthesis of new antimicrobial drugs.
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http://dx.doi.org/10.1016/j.ejmech.2021.113696DOI Listing
July 2021

Ferromagnetic TiCNCl-decorated RGO aerogel: From 3D interconnecting conductive network construction to ultra-broadband microwave absorber with thermal insulation property.

J Colloid Interface Sci 2021 May 30;604:402-414. Epub 2021 May 30.

State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.

It remains urgent challenges to adopt suitable strategies to consume unwanted microwave pollution emitted by high-tech electronic devices satisfactorily. Confronted with narrow effective absorption bandwidth (EAB) and high filler loading bottlenecks of MXene-Based microwave absorber, herein, we employ Lewis molten salt etching approach to both exfoliate TiAlCN powders into TiCNCl suspension and intercalate ferromagnetic composition into interlamination simultaneously. By utilizing the crosslinking effect of dopamine, the TiCNCl are anchored on the surfaces of graphene oxide (GO) nanosheets, constructing interconnecting microstructure. Both the 3D conductive network and the modification of MXene manifest crucial impacts on enhancing microwave absorption performance of the resulting ultra-lightweight reduced GO (RGO)-based aerogel. The minimum intensity of reflection loss achieves -62.62 dB with the absorber mass loading of 0.7 wt%. Remarkably, more than 90% of the incident microwave is qualified to be absorbed over the whole Ku band. The EAB is broadened while tailoring the thickness to 3 mm, ranging from 10.2 to 18 GHz. Besides, the aerogel presents valuable thermal insulation properties. Our methodology of synthesizing MXene/RGO aerogel not only provides promising insights into microstructural construction but also endows the possibility for integrating thermal insulation property towards next-generation high-performance microwave absorption devices.
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http://dx.doi.org/10.1016/j.jcis.2021.05.166DOI Listing
May 2021

Frequency tuning behaviour of terahertz quantum cascade lasers revealed by a laser beating scheme.

Opt Express 2021 Jul;29(14):21269-21279

In the terahertz frequency range, the commercialized spectrometers, such as the Fourier transform infrared and time domain spectroscopies, show spectral resolutions between a hundred megahertz and a few gigahertz. Therefore, the high precision frequency tuning ability of terahertz lasers cannot be revealed by these traditional spectroscopic techniques. In this work, we demonstrate a laser beating experiment to investigate the frequency tuning characteristics of terahertz quantum cascade lasers (QCLs) induced by temperature or drive current. Two terahertz QCLs emitting around 4.2 THz with identical active regions and laser dimensions (150 µm wide and 6 mm long) are employed in the beating experiment. One laser is operated as a frequency comb and the other one is driven at a lower current to emit a single frequency. To measure the beating signal, the single mode laser is used as a fast detector (laser self-detection). The laser beating scheme allows the high precision measurement of the frequency tuning of the single mode terahertz QCL. The experimental results show that in the investigated temperature and current ranges, the frequency tuning coefficients of the terahertz QCL are 6.1 MHz/0.1 K (temperature tuning) and 2.7 MHz/mA (current tuning) that cannot be revealed by a traditional terahertz spectrometer. The laser beating technique shows potential abilities in high precision linewidth measurements of narrow absorption lines and multi-channel terahertz communications.
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http://dx.doi.org/10.1364/OE.427326DOI Listing
July 2021

Interaction between antibiotic use and MS4A2 gene polymorphism on childhood eczema: a prospective birth cohort study.

BMC Pediatr 2021 Jul 14;21(1):314. Epub 2021 Jul 14.

Department of Pediatric Pulmonology, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, China.

Background: Eczema is usually the first allergic manifestation to appear in life attributed to gene-environment interactions. IL13, IL4, MS4A2 and ILR4A are four key inflammatory genes associated with atopy. This study aimed to explore gene-environment interactions on eczema in early life among the above four genes and environmental factors in Chinese Han children.

Methods: Five hundred ninety-seven children from a birth cohort who completed two-year follow-up were enrolled and their cord blood was collected. Subjects were genotyped for six polymorphisms in the aforementioned four genes. The children were followed at 6, 12 and 24 months, with epidemiologic information and medical history of eczema collected by questionnaire and eczema assessed by dermatologists.

Results: Among the 597 children, 168 were diagnosed with eczema and the others were not after 2 years of follow-up. MS4A2 rs569108 GG genotype (P = 1.68E-02, odds ratio (OR) = 4.66) and antibiotic use (P = 3.75E-4, OR = 2.02) were found independently associated with development of childhood eczema. Children with both antibiotic use and MS4A2 rs569108 GG genotype were more likely to develop eczema than those with only antibiotic use or GG homozygote (OR = 6.24 VS. 2.04 or 4.68).

Conclusions: MS4A2 rs569108 polymorphism and antibiotic use were solely associated with eczema, and they interacted with each other to increase the risk of developing the disease in Chinese Han toddlers. Long-term follow-up along with functional and replication studies are still needed.
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http://dx.doi.org/10.1186/s12887-021-02786-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8278718PMC
July 2021

Pollution risk estimation of the Cu element in atmospheric sedimentation samples by laser induced breakdown spectroscopy (LIBS) combined with random forest (RF).

Anal Methods 2021 Jul 13. Epub 2021 Jul 13.

Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi'an, 710127, China. and College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an, 710065, China.

Laser-induced breakdown spectroscopy (LIBS) combined with the random forest (RF) algorithm was proposed to predict three pollution indexes (geo-accumulation index, enrichment factor, and potential ecological risk index) of the Cu element in atmospheric sedimentation samples to evaluate the pollution risk. To begin with, the LIBS spectra of 15 atmospheric sedimentation samples from different locations were collected and the copper element was identified using the National Institute of Standards and Technology (NIST) database. Then, the influence of different spectral pretreatment methods (MSC, WT and D1st) on the predictive performance of the RF was discussed according to the calibration set with the determination coefficient (Rc2) and mean relative error (MREC) as evaluation indexes. Next, in order to obtain a better RF calibration model, a variable importance (VI) measurement was applied to select input variables from LIBS spectral data based on the optimal spectral pretreatment method, and the optimal variable importance threshold was selected as the input variable to establish the RF calibration model. Finally, the predictive performance of the optimal RF calibration model was verified using the prediction set with the determination coefficient (Rp2) and the mean relative error (MREP). The results show that Rp2 of the geo-accumulation index, enrichment factor and potential ecological risk index is up to 0.9971, 0.9919 and 0.9290, respectively, and MREP of the three indexes is 0.0234, 0.1173 and 0.0810, respectively; the average relative standard deviation (RSD) of the prediction set for the three indexes is 2.16%, 5.78% and 0.71%, respectively. Furthermore, it can be inferred that Cu was at levels corresponding to serious pollution primarily because of anthropogenic activities based on the predictive Igeo, Er and RI values. Therefore, LIBS combined with the RF algorithm is a promising means which can achieve fast and simple estimation of the pollution risk degree of Cu in atmospheric sedimentation samples without complicated sample preparation to provide a basis for pollution prevention and control measures.
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http://dx.doi.org/10.1039/d1ay00879jDOI Listing
July 2021

Imaging adsorption of iodide on single CuO microparticles reveals the acid activation mechanism.

J Hazard Mater 2021 Jul 2;420:126539. Epub 2021 Jul 2.

National Collaborative Innovation Center for Nuclear Waste and Environmental Safety, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, PR China. Electronic address:

Imaging an adsorption reaction taking place at the single-particle level is a promising avenue for fundamentally understanding the adsorption mechanism. Here, we employ a dark-field microscopy (DFM) method for in situ imaging the adsorption process of I on single CuO microparticles to reveal the acid activation mechanism. Using the time-lapsed DMF imaging, we find that a relatively strong acid is indispensable to trigger the adsorption reaction of I on single CuO microparticle. A hollow microparticle with the increase in size is obtained after the adsorption reaction, causing the enhancement of the scattering intensity. Correlating the change of the scattering light intensity or particle size with adsorption capacity of I, we quantitatively analyze the selective uptake, slightly heterogeneous adsorption behavior, pH/temperature-dependent adsorption capacity, and adsorption kinetics as well as isotherms of individual CuO microparticles for I. Our observations demonstrate that the acid-initiated Kirkendall effect is responsible for the high-reaction activity of single CuO microparticles for adsorption of I in the acidic environment, through breaking the unfavorable lattice energy between CuO and CuI as well as generating high-active hollow intermediate microparticle.
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http://dx.doi.org/10.1016/j.jhazmat.2021.126539DOI Listing
July 2021

SNHG17 Serves as an Oncogenic lncRNA by Regulating the miR-361-3p/STC2 Axis in Rectal Cancer.

Front Genet 2021 23;12:654686. Epub 2021 Jun 23.

Department of Hepatobiliary Surgery, Affiliated Hospital of Youjiang Medical University for Nationalities, Baise, China.

Long noncoding RNA (lncRNA) have been reported to be crucial regulators for carcinogenesis, including rectal cancer. This work aimed to explore the roles and associated mechanisms of small nucleolar RNA host gene 17 (SNHG17) in rectal cancer. A quantitative real-time polymerase chain reaction was performed to measure the expression level of SNHG17 in rectal cancer tissues and cells. Cell counting kit-8 (CCK-8) assay and flow cytometry assay were conducted to measure the biological roles of SNHG17 in rectal cancer. In addition, luciferase activity reporter assay, RNA immunoprecipitation (RIP) assay, and rescue experiments were conducted to explore the mechanisms of SNHG17 in rectal cancer. The upregulation status of SNHG17 was identified in rectal cancer tissues and cells. Functionally, knockdown the expression of SNHG17 inhibits rectal cancer cell proliferation stimulating cell apoptosis. assay showed that the knockdown of SNHG17 inhibits tumor growth. Furthermore, we showed that microRNA-361-3p (miR-361-3p) has decreased expression in tumor tissues and cells, and SNHG17 functions as a sponge for miR-361-3p. The upregulation status of stanniocalcin 2 (STC2) was also found in rectal cancer, and the knockdown of STC2 hinders cancer progression. In conclusion, lncRNA SNHG17 functions as an oncogenic lncRNA in rectal cancer by regulating the miR-361-3p/STC2 axis.
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http://dx.doi.org/10.3389/fgene.2021.654686DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8260683PMC
June 2021

Gene-gene and gene-environment interactions on cord blood total IgE in Chinese Han children.

Allergy Asthma Clin Immunol 2021 Jul 9;17(1):69. Epub 2021 Jul 9.

Department of Pediatric Pulmonology, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, China.

Background: IL13, IL4, IL4RA, FCER1B and ADRB2 are susceptible genes of asthma and atopy. Our previous study has found gene-gene interactions on asthma between these genes in Chinese Han children. Whether the interactions begin in fetal stage, and whether these genes interact with prenatal environment to enhance cord blood IgE (CBIgE) levels and then cause subsequent allergic diseases have yet to be determined. This study aimed to determine whether there are gene-gene and gene-environment interactions on CBIgE elevation among the aforementioned five genes and prenatal environmental factors in Chinese Han population.

Methods: 989 cord blood samples from a Chinese birth cohort were genotyped for nine single-nucleotide polymorphisms (SNPs) in the five genes, and measured for CBIgE levels. Prenatal environmental factors were collected using a questionnaire. Gene-gene and gene-environment interactions were analyzed with generalized multifactor dimensionality methods.

Results: A four-way gene-gene interaction model (IL13 rs20541, IL13 rs1800925, IL4 rs2243250 and ADRB2 rs1042713) was regarded as the optimal one for CBIgE elevation (testing balanced accuracy = 0.5805, P = 9.03 × 10). Among the four SNPs, only IL13 rs20541 was identified to have an independent effect on elevated CBIgE (odds ratio (OR) = 1.36, P = 3.57 × 10), while the other three had small but synergistic effects. Carriers of IL13 rs20541 TT, IL13 rs1800925 CT/TT, IL4 rs2243250 TT and ADRB2 rs1042713 AA were estimated to be at more than fourfold higher risk for CBIgE elevation (OR = 4.14, P = 2.69 × 10). Gene-environment interaction on elevated CBIgE was found between IL4 rs2243250 and maternal atopy (OR = 1.41, P = 2.65 × 10).

Conclusions: Gene-gene interaction between IL13 rs20541, IL13 rs1800925, IL4 rs2243250 and ADRB2 rs1042713, and gene-environment interaction between IL4 rs2243250 and maternal atopy begin in prenatal stage to augment IgE production in Chinese Han children.
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http://dx.doi.org/10.1186/s13223-021-00571-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8268446PMC
July 2021

YAP-Dependent Induction of CD47-Enriched Extracellular Vesicles Inhibits Dendritic Cell Activation and Ameliorates Hepatic Ischemia-Reperfusion Injury.

Oxid Med Cell Longev 2021 22;2021:6617345. Epub 2021 Jun 22.

Department of Hepatic Surgery and Liver Transplantation Center, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.

Hepatic ischemia-reperfusion injury (IRI) is the most common cause of liver damage leading to surgical failures in hepatectomy and liver transplantation. Extensive inflammatory reactions and oxidative responses are reported to be the major processes exacerbating IRI. The involvement of Yes-associated protein (YAP) in either process has been suggested, but the role and mechanism of YAP in IRI remain unclear. In this study, we constructed hepatocyte-specific YAP knockout (YAP-HKO) mice and induced a hepatic IRI model. Surprisingly, the amount of serum EVs decreased in YAP-HKO compared to WT mice during hepatic IRI. Then, we found that the activation of YAP increased EV secretion through F-actin by increasing membrane formation, while inhibiting the fusion of multivesicular body (MVB) and lysosomes in hepatocytes. Further, to explore the essential elements of YAP-induced EVs, we applied mass spectrometry and noticed CD47 was among the top targets highly expressed on hepatocyte-derived EVs. Thus, we enriched CD47 EVs by microbeads and applied the isolated CD47 EVs on IRI mice. We found ameliorated IRI symptoms after CD47 EV treatment in these mice, and CD47 EVs bound to CD172 on the surface of dendritic cells (DCs), which inhibited DC activation and the cascade of inflammatory responses. Our data showed that CD47-enriched EVs were released in a YAP-dependent manner by hepatocytes, which could inhibit DC activation and contribute to the amelioration of hepatic IRI. CD47 EVs could be a potential strategy for treating hepatic IRI.
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http://dx.doi.org/10.1155/2021/6617345DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8241504PMC
June 2021

A novel systematic approach for cancer treatment prognosis and its applications in oropharyngeal cancer with microRNA biomarkers.

Bioinformatics 2021 Apr 29. Epub 2021 Apr 29.

Carle Cancer Center, Carle Foundation Hospital, Urbana, IL, USA.

Motivation: Predicting early in treatment whether a tumor is likely to respond to treatment is one of the most difficult yet important tasks in providing personalized cancer care. Most oropharyngeal squamous cell carcinoma (OPSCC) patients receive standard cancer therapy. However, the treatment outcomes vary significantly and are difficult to predict. Multiple studies indicate that microRNAs (miRNAs) are promising cancer biomarkers for the prognosis of oropharyngeal cancer. The reliable and efficient use of miRNAs for patient stratification and treatment outcome prognosis is still a very challenging task, mainly due to the relatively high dimensionality of miRNAs compared to the small number of observation sets; the redundancy, irrelevancy and uncertainty in the large amount of miRNAs; and the imbalanced observation patient samples.

Results: In this study, a new machine learning-based prognosis model was proposed to stratify subsets of OPSCC patients with low and high risks for treatment failure. The model cascaded a two-stage prognostic biomarker selection method and an evidential K-nearest neighbors (EK-NN) classifier to address the challenges and improve the accuracy of patient stratification. The model has been evaluated on miRNA expression profiling of 150 oropharyngeal tumors by use of overall survival and disease-specific survival as the end points of disease treatment outcomes, respectively. The proposed method showed superior performance compared to other advanced machine-learning methods in terms of common performance quantification metrics. The proposed prognosis model can be employed as a supporting tool to identify patients who are likely to fail standard therapy and potentially benefit from alternative targeted treatments.
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http://dx.doi.org/10.1093/bioinformatics/btab242DOI Listing
April 2021

Realizing Compact Lithium Deposition via Elaborative Nucleation and Growth Regulation for Stable Lithium-Metal Batteries.

ACS Appl Mater Interfaces 2021 Jul 8;13(29):34248-34257. Epub 2021 Jul 8.

Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China.

Metallic lithium (Li) has been regarded as an ideal candidate for anode materials in next-generation high-energy-density batteries. However, a ubiquitous spongy Li deposition results in low reversibility, huge interfacial impedance, and even safety issues, hindering its practical application. Herein, we proposed a bifunctional electrolyte (BiFE) to avoid the spongy Li deposition, in which lithium nitrate (LiNO) facilitates a uniform granular Li nucleation via forming a kinetically favorable solid electrolyte interphase and silicon dioxide (SiO) adsorbs anions to stabilize the electric field distribution near the electrode surface. Such a BiFE provides an even Li ion flux for the subsequent growth of electrochemical Li deposition, which was verified by ζ potential, Raman spectra, and specific capacitance characterizations, thus realizing a compact and uniform Li deposition via elaborative nucleation and growth regulation. An improved Li Coulombic efficiency of 99.1% can be achieved within BiFE. When used in Cu∥Li half-cells and Li∥Li symmetric cells, the high Li utilization prolonged the cycling life span to above 300 cycles and 1200 h, respectively. The compact Li deposition also resisted the corrosion of polysulfides to enhance the cycling performance of Li∥S full cells.
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http://dx.doi.org/10.1021/acsami.1c07624DOI Listing
July 2021

Diterpenoids from the genus Euphorbia: Structure and biological activity (2013-2019).

Phytochemistry 2021 Jul 3;190:112846. Epub 2021 Jul 3.

Wuya College of Innovation, Key Laboratory of Structure-Based Drug Design & Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, People's Republic of China. Electronic address:

Euphorbiaceae is one of the largest families of higher plants, including 7500 species, and many of them are used as medicines in China. From 2013 to 2019, a total of 455 previously undescribed diterpenoids were isolated from 53 species of Euphorbia, and some skeleton types were first discovered from the genus Euphorbia. Most of the diterpenoids isolated from Euphorbia spp. have been tested for their biological activity, and some of them were first reported for Euphorbia diterpenoids in recent years, such as neuroprotection, antimalarial activity and inhibition of osteoclast formation. In this review, we summarize all the isolated diterpenoids from the genus Euphorbia according to their skeleton types, classify all these diterpenoids into 26 normal classes and 37 novel skeleton types, and summarize their biological activity.
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http://dx.doi.org/10.1016/j.phytochem.2021.112846DOI Listing
July 2021

Research on obstetric ward planning combining lean thinking and mixed-integer programming.

Int J Qual Health Care 2021 Jul;33(3)

School of Nursing, Jilin University, No. 965, Xinjiang Street, Chaoyang District, Changchun, Jilin 130000, China.

Background: In recent years, there are many studies on scheduling methods of patient flow, nurse scheduling, bed allocation, operating room scheduling and other problems, but there is no report on the research methods of how to plan ward allocation from a more macroscopic perspective.

Objective: Refine and stratify the obstetric ward to provide more accurate medical service for pregnant women and improve the work efficiency of obstetricians and midwives. The problem of how to allocate the number of each type of ward is modeled as a mixed integer programming problem, which maximizes the patient flow of pregnant women in obstetric hospitals.

Methods: The obstetric wards are divided into observation ward, cesarean section ward and natural delivery ward according to lean thinking. CPLEX is used to solve the mixed-integer programming problem of ward allocation. In R software, multivariate Generalized Linear Models (GLM) regression model is used to analyze the influence of each factor on patient flow.

Results: The maximum patient flow of each case was obtained by CPLEX, which was 19-25% higher than that of patients without refinement, stratification and planning. GLM regression analysis was carried out on the abovementioned data, and the positive and negative correlation factors were obtained.

Conclusion: According to lean thinking, obstetric wards are divided into three types of wards. Obstetricians and midwives work more efficiently and get more rest time. Pregnant women also enjoy more detailed medical services. By modeling the delivery ward allocation problem as a mixed-integer programming problem, we can improve the capacity of the service in obstetric hospitals from a macro perspective. Through GLM regression model analysis, it is conducive to improve the obstetric hospital capacity from the perspective of positive and negative correlation factors.
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http://dx.doi.org/10.1093/intqhc/mzab101DOI Listing
July 2021

Tetramethylpyrazine inhibits proliferation of colon cancer cells .

World J Clin Cases 2021 Jun;9(18):4542-4552

Institute of Cancer Control, Xingtai People's Hospital, Xingtai 054001, Hebei Province, China.

Background: Colon cancer is one of the most common malignancies worldwide, and chemotherapy is a widely used strategy in colon cancer clinical therapy. However, chemotherapy resistance is a major cause of disease recurrence and progression in colon cancer, and thus novel drugs for treatment are urgently needed. Tetramethylpyrazine (TMP), a component of the traditional Chinese medicine Chuanxiong Hort, has been proven to exhibit a beneficial effect in tumors.

Aim: To investigate the potential anticancer activity of TMP in colon cancer and its underlying mechanisms.

Methods: Colon cancer cells were incubated with different concentrations of TMP. Cell viability was evaluated by crystal violet staining assay and cell counting kit-8 assay, and cell apoptosis and cell cycle were assessed by flow cytometry.

Results: TMP significantly inhibited the proliferation of colon cancer cells in a dose- and time-dependent manner. In addition, flow cytometry revealed that TMP induced cell cycle arrest at the G0/G1 phase. TMP treatment caused early stage apoptosis in SW480 cells, whereas it caused late stage apoptosis in HCT116 cells.

Conclusion: Our studies demonstrated that TMP inhibits the proliferation of colon cancer cells in a dose- and time-dependent manner by inducing apoptosis and arresting the cell cycle at the G0/G1 phase. Our findings suggest that TMP might serve as a potential novel therapeutic drug in the treatment of human colon cancer.
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http://dx.doi.org/10.12998/wjcc.v9.i18.4542DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8223836PMC
June 2021

Effects of surface oxidation on the pH-dependent surface charge of oxidized aluminum gallium nitride.

J Colloid Interface Sci 2021 Jun 24;603:604-614. Epub 2021 Jun 24.

School of Molecular Sciences, The University of Western Australia, Perth, WA 6009, Australia. Electronic address:

Hypothesis: The properties of the oxidized surface for common materials, such as silicon and titanium, are known to be markedly different from the reduced surface. We hypothesize that surface-oxidized aluminum gallium nitride ((oxidized-AlGaN)/GaN) surface charge behavior is different to unoxidized AlGaN (with ultrathin native oxide only), which can be validated via surfactant adsorption. Understanding these differences will explain why (oxidized-AlGaN)/GaN-based sensors are better performing than AlGaN ones, which has been previously demonstrated but not understood.

Experiments: The surface of an AlGaN/GaN structure was oxidized with hot piranha solution and oxygen plasma. AFM force measurements and imaging were performed to probe the charge properties of the surface in aqueous solutions of varying pH containing only an acid or base, or with an added ionic surfactant: cationic cetyltrimethylammonium bromide (CTAB) or anionic sodium dodecylsulfate (SDS).

Findings: The (oxidized-AlGaN)/GaN surface is positively charged at pH 4 and pH 5.5, although pH 5.5 should be close to the isoelectric point of the surface. The surface is negatively charged at pH 10 and pH 12, and sufficiently charged to attract cooperative adsorption of CTAB aggregates at pH 12. At pH 2, the evidence is inconclusive, but the surface is most likely positively charged. Compared to unoxidized AlGaN, the (oxidized-AlGaN)/GaN surface shows a wider range of surface charge magnitude over pH values between 2 and 12. This suggests that the (oxidized-AlGaN)/GaN surface has a higher surface hydroxyl group density than unoxidized AlGaN, which explains the higher sensitivity for pH sensors based on (oxidized-AlGaN)/GaN structures.
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http://dx.doi.org/10.1016/j.jcis.2021.06.126DOI Listing
June 2021
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