Publications by authors named "Kai Yue"

64 Publications

The PSMD14 inhibitor Thiolutin as a novel therapeutic approach for esophageal squamous cell carcinoma through facilitating SNAIL degradation.

Theranostics 2021 3;11(12):5847-5862. Epub 2021 Apr 3.

Department of Maxillofacial and Otorhinolaryngological Oncology, Tianjin Medical University Cancer Institute and Hospital, Key Laboratory of Cancer Prevention and Therapy, Tianjin Cancer Institute, National Clinical Research Center of Cancer, Tianjin 300060, China.

Metastasis and chemoresistance are major causes of poor prognosis in patients with esophageal squamous cell carcinoma (ESCC), manipulated by multiple factors including deubiquitinating enzyme (DUB). DUB PSMD14 is reported to be a promising therapeutic target in various cancers. Here, we explored the antitumor activity of Thiolutin (THL), the PSMD14 inhibitor, as a new therapy strategy in ESCC. Through 4-NQO-induced murine ESCC model, we investigated the expression of PSMD14 in esophageal tumorigenesis. Ubiquitin-AMC assay was performed to evaluate DUB activity of PSMD14 with THL treatment. The effect of THL on epithelial-to-mesenchymal transition (EMT), invasion, stemness and chemosensitivity was detected by using and experiments. Immunoprecipitation and ubiquitination assay were conducted to examine whether THL could impair the deubiquitination and stability of SNAIL regulated by PSMD14. Compared with normal esophageal epithelium, PSMD14 was upregulated in 4-NQO-induced murine esophageal epithelium dysplasia and ESCC tissues. THL could significantly weaken DUB activity of PSMD14. Furthermore, the results of and assays showed that THL efficiently suppressed motility and stemness and increased sensitivity to cisplatin in ESCC. Mechanically, THL impaired the interaction between PSMD14 and SNAIL, then promoted the ubiquitination and degradation of SNAIL to inhibit EMT which plays a crucial role in ESCC metastasis, stemness and chemosensitivity. TCGA database analysis revealed that high concomitant PSMD14/SNAIL expression predicted shorter overall survival in esophageal cancer. Our findings demonstrate for the first time that suppression of PSMD14/SNAIL axis by THL could be a novel and promising therapeutic approach for ESCC clinical therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7150/thno.46109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8058732PMC
April 2021

Global patterns and drivers of rainfall partitioning by trees and shrubs.

Glob Chang Biol 2021 Apr 16. Epub 2021 Apr 16.

CREAF, Cerdanyola del Vallès, Spain.

Spatiotemporal redistribution of incident rainfall in vegetated ecosystems results from the partitioning by plants into intercepted, stemflow, and throughfall fractions. However, variation in patterns and drivers of rainfall partitioning across global biomes remains poorly understood, which limited the ability of climate models to improve the predictions of biome hydrological cycle under global climate change scenario. Here, we synthesized and analyzed the partitioning of incident rainfall into interception, stemflow, and throughfall by trees and shrubs at the global scale using 2430 observations from 236 independent publications. We found that (1) globally, median levels of relative interception, stemflow, and throughfall accounted for 21.8%, 3.2%, and 73.0% of total incident rainfall, respectively; (2) rainfall partitioning varied among different biomes, due to variation in plant composition, canopy structure, and macroclimate; (3) relative stemflow tended to be driven by plant traits, such as crown height:width ratio, basal area, and height, while relative interception and throughfall tended to be driven by plant traits as well as meteorological variables. Our global assessment of patterns and drivers of rainfall partitioning underpins the role of meteorological factors and plant traits in biome-specific ecohydrological cycles. We suggest to include these factors in climate models to improve the predictions of local hydrological cycles and associated biodiversity and function responses to changing climate conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/gcb.15644DOI Listing
April 2021

Diagnostic Model Incorporating Clinicopathological Characteristics of Delphian Lymph Node Metastasis Risk Profiles in Papillary Thyroid Cancer.

Front Endocrinol (Lausanne) 2021 25;12:591015. Epub 2021 Mar 25.

Department of Maxillofacial & E.N.T. Oncology, Tianjin Medical University Cancer Institute & Hospital, Key Laboratory of Cancer Prevention and Therapy, Tianjin Cancer Institute, National Clinical Research Center of Cancer, Tianjin, China.

The Delphian lymph node (DLN), also known as the prelaryngeal node, is one component of the central lymph node. The DLN has been well studied in laryngeal cancer, although its significance in papillary thyroid cancer (PTC) remains unclear. We retrospectively analyzed 936 patients with PTC who underwent thyroidectomy by a single surgeon in Tianjin Cancer Hospital from 2017 to 2019. Moreover, 250 PTC patients who underwent thyroidectomy by another surgeon in Tianjin Cancer Hospital from January 2019 to April 2019 were used as a validation cohort. Among the 936 patients with PTC, 581 patients (62.1%) had DLNs, of which 177 samples with metastasis (177/581, 30.5%) were verified. DLN metastasis was significantly correlated with sex, age, tumor size, bilateral cancer, multifocality, extrathyroidal extension, lymphovascular invasion and central and lateral neck lymph node metastasis. Multivariate analysis revealed that independent risk factors for DLN metastasis included age, gender, tumor size, extrathyroid extension, lymphovascular invasion and central lymph node metastasis, which determined the nomogram. In particular, tumor size was proven to be one of the most predominant single predictors. The diagnostic model had an area under the curve (AUC) of 0.829 (95% confidence interval, 0.804-0.854). The internal and external validations of the nomogram were 0.819 and 0.745, respectively. Our results demonstrate that DLN metastasis appears to be a critical parameter for predicting metastatic disease of the central compartments. Furthermore, this study provides a precise criterion for assessing DLN metastasis and has great clinical significance for treating PTC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fendo.2021.591015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8027498PMC
March 2021

CFD Analysis of a Water Vaporization Process in a Three-Dimensional Spouted Bed for Flue Gas Desulfurization.

ACS Omega 2021 Feb 22;6(4):2759-2766. Epub 2021 Jan 22.

School of Chemical Engineering, Northwest University, Xi'an 710069, China.

In this work, the gas-solid flow and water vaporization process are simulated by the method of Euler-Eulerian two-fluid model in a three-dimensional spouted bed, which have a significant influence on the desulfurization efficiency. The results of simulation indicate that the change trends of the particle volume fraction are similar under superficial gas velocities of 0.7 and 0.8 m/s. The degree of particle pulsation is the highest at the bottom of the spout area, and the degree of gas pulsation is the highest at the junction of the annulus area and spout area. The temperatures of gas, liquid, and particles are also analyzed. The results demonstrate that in the spout area, the gas temperature is much higher than that of the liquid and particles, but the three phases are uniformly mixed and have similar temperatures in other areas. Moreover, water vaporization mainly occurs at the junction of the annulus area and the spout area, a small amount of liquid is vaporized at the center of the spout area, and basically no vaporization reaction occurs in the outer radius of the annulus area. With the increase in gas velocity, gas temperature, and liquid temperature and the decrease in gas humidity, water vaporization reaction is promoted.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.0c05056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7860078PMC
February 2021

Resveratrol attenuates methamphetamine-induced memory impairment via inhibition of oxidative stress and apoptosis in mice.

J Food Biochem 2021 Feb 27;45(2):e13622. Epub 2021 Jan 27.

Wuhan Institutes of Biomedical Sciences, School of Medicine, Jianghan University, Wuhan, China.

Methamphetamine (METH) abuse produces serious neurotoxicity to the central nervous system along with long-term cognitive dysfunction. Resveratrol, a natural polyphenol, has broad application prospects in the treatment of neurodegenerative diseases. Therefore, this study was conducted to investigate whether resveratrol might alleviate METH-induced memory deficits in vivo. We found that multiple exposures to METH significantly impaired cognitive functions and caused long-lasting memory deficits (p < .05). Pretreatment of resveratrol (10 or 100 mg/kg) remarkably attenuated METH-induced memory impairment in mice (p < .05). Bioinformatics analysis results showed that resveratrol might alleviate memory deficits by inhibiting METH-induced oxidative damage and apoptosis. Molecular docking showed that resveratrol had hydrogen bonding interactions with Kelch-like ECH associated protein 1 (Keap1), a repressor protein of the classic antioxidant Keap1-Nrf2 pathway. Further results validated oxidative stress parameters, apoptosis, and expression of Keap1 were significantly increased, while the translocation and activation of nuclear factor erythroid 2-related factor 2 (Nrf2) into the nucleus and expression of its downstream proteins were greatly decreased in the hippocampus after METH exposure (p < .05). These changes caused by METH could be prevented by resveratrol (p < .05). Therefore, these findings suggested that the prevention of resveratrol on memory dysfunction induced by METH was possibly related to the activation of the Keap1-Nrf2 pathway and reduction of apoptosis. Supplementation of resveratrol could be a potential treatment for preventing the neurotoxicity of METH in the future. PRACTICAL APPLICATIONS: As one of the worst commonly abused psychostimulants, methamphetamine (METH) addiction produces serious complications including cognitive impairment and memory deficits. Resveratrol is a natural polyphenol that has important nutritional supplements and protective effects in the treatment of many neurodegenerative diseases. In this study, the results of bioinformatics prediction and experimental validation showed that resveratrol might effectively prevent memory impairment via the interaction with Keap1, activation of the Keap1-Nrf2 pathway, and inhibition of DNA damage and apoptotic responses post METH exposure. Therefore, these findings provide new ideas and insights into the application of resveratrol in the treatment of nervous system damage caused by METH.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/jfbc.13622DOI Listing
February 2021

Blockade of deubiquitinating enzyme PSMD14 overcomes chemoresistance in head and neck squamous cell carcinoma by antagonizing E2F1/Akt/SOX2-mediated stemness.

Theranostics 2021 1;11(6):2655-2669. Epub 2021 Jan 1.

Department of Maxillofacial and Otorhinolaryngological Oncology, Tianjin Medical University Cancer Institute and Hospital, Key Laboratory of Cancer Prevention and Therapy, Tianjin Cancer Institute, National Clinical Research Center of Cancer, Tianjin 300060, China.

Increasing evidence reveals a close relationship between deubiquitinating enzymes (DUBs) and cancer progression. In this study, we attempted to identify the roles and mechanisms of critical DUBs in head and neck squamous cell carcinoma (HNSCC). Bioinformatics analysis was performed to screen differentially expressed novel DUBs in HNSCC. Immunohistochemistry assay was used to measure the expression of DUB PSMD14 in HNSCC specimens and adjacent normal tissues. The level of PSMD14 in HNSCC tumorigenesis was investigated using a 4-NQO-induced murine HNSCC model. The function of PSMD14 was determined through loss-of-function assays. Chromatin immunoprecipitation, immunoprecipitation and ubiquitination assay were conducted to explore the potential mechanism of PSMD14. The anti-tumor activity of PSMD14 inhibitor Thiolutin was assessed by and experiments. We identified PSMD14 as one of significantly upregulated DUBs in HNSCC tissues. Aberrant expression of PSMD14 was associated with tumorigenesis and malignant progression of HNSCC and further indicated poor prognosis. The results of and experiments demonstrated PSMD14 depletion significantly undermined HNSCC growth, chemoresistance and stemness. Mechanically, PSMD14 inhibited the ubiquitination and degradation of E2F1 to improve the activation of Akt pathway and the transcription of SOX2. Furthermore, PSMD14 inhibitor Thiolutin exhibited a potent anti-tumor effect on HNSCC and by impairing DUB activity of PSMD14. Our findings demonstrate the role and mechanism of PSMD14 in HNSCC, and provide a novel and promising target for diagnosis and clinical therapy of HNSCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7150/thno.48375DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7806466PMC
January 2021

Pre-treatment circulating neutrophil count is an independent prognostic factor in oropharyngeal cancer.

Ann Transl Med 2020 Sep;8(18):1135

Department of Maxillofacial and E.N.T. Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.

Background: Oropharyngeal cancer (OPC) is a type of head and neck squamous cell cancer, the incidence of which has increased in recent years. Many studies have reported a variety of prognostic markers of OPC, but they are either expensive or difficult to obtain. Therefore, we retrospectively studied the prognostic value of circulating neutrophil count (CNC) in patients with OPC, with the aim of providing a theoretical basis for further prognostic stratification.

Methods: The clinicopathological data of 153 patients diagnosed with OPC from January 2010 to June 2017 were retrospectively analyzed. The CNC of each patient was measured before treatment. Then, the relationship between CNC and the clinicopathological characteristics of the patients was analyzed. The receiver operating characteristic (ROC) curve was used to calculate the cutoff value of CNC. The cox proportional hazards model was used to perform univariate and multivariate analysis of the relevant prognostic factors to determine the factors related to overall survival (OS) and progression-free survival (PFS).

Results: The cutoff value for CNC was 4.48. Neutrophilia was significantly associated with disease stage, P16 status, and the type of therapy. In the univariate and multivariate analyses, CNC was found to be correlated with OS and PFS. Increased neutrophil count was predictive of poor OS (P<0.001) and PFS (P=0.001). Neutrophil count was an independent risk factor for OS (HR =2.09, 95% CI: 1.25-3.51, P=0.005) and PFS (HR =1.78, 95% CI: 1.10-2.88, P=0.02) in patients with OPC.

Conclusions: Pre-treatment CNC is an independent prognostic factor for OPC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.21037/atm-20-5702DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7576053PMC
September 2020

Prognostic significance of pre-treatment serum Cyfra21-1 as a tumor marker in patients with oropharyngeal squamous cell carcinoma treated with concurrent chemoradiotherapy.

Ann Transl Med 2020 Oct;8(20):1302

Department of Maxillofacial & E.N.T Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.

Background: Oropharyngeal squamous cell carcinoma (OPSCC) is a kind of squamous cell carcinoma of head and neck, and its incidence is on the rise in recent years. A variety of prognostic markers for OPSCC have been reported in many studies, but they are expensive or difficult to obtain. So, we retrospectively studied the prognostic significance of cytokeratin 19 soluble fragment (Cyfra21-1) in patients with OPSCC, in order to provide theoretical basis for accurate prognosis assessment.

Methods: A retrospective analysis of the clinicopathological data of 85 OPSCC patients with concurrent radiotherapy and chemotherapy (CRT) admitted from January 2010 to June 2017. Serum Cyfra21-1 levels were measured before treatment. Analyze the relationship between Cyfra21-1 and clinical pathological characteristics of patients. The receiver operating characteristic (ROC) curve was used to calculate the cut-off value of Cyfra21-1. The Cox proportional hazard model was used to conduct univariate and multivariate analysis of related prognostic factors, and to determine the factors related to overall survival (OS) and progression-free survival (PFS).

Results: The cutoff value for Cyfra21-1 was 2.93 ng/mL. The baseline data of patients in different Cyfra21-1 groups were balanced and comparable. In the univariate and multivariate analyses, it was found that Cyfra21-1 was associated with OS and PFS. A measurement of Cyfra21-1 ≥2.93 ng/mL indicated poor OS (P<0.001) and PFS (P=0.001). After adjusting for age and disease stage, Cyfra21-1 can independently affect the OS (HR =3.57, 95% CI: 1.60-7.99, P=0.002) and PFS (HR =2.89, 95% CI: 1.41-5.91, P=0.004) of patients with OPSCC treated with CRT.

Conclusions: Pre-treatment Cyfra21-1 can be used as a prognostic marker for patients with OPSCC treated with CRT, which has important clinical significance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.21037/atm-20-6124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7661861PMC
October 2020

Comparison of the curative effect of modified medial arc incision of achilles tendon and traditional straight incision in the treatment of old achilles tendon rupture.

Pak J Pharm Sci 2020 May;33(3):1087-1093

Departments of Orthopedics, The First People's Hospital of Longquanyi District of Chengdu, Sichuan, Chengdu, China.

Modified medial arc incision of Achilles tendon and traditional straight incision were applied to treat 50 cases of old rupture of Achilles tendon. Among them, there were 20 cases involved in the modified medial arc incision of Achilles tendon (group A).Furthermore, 30 cases accepted traditional straight incision treatment (group B). The same rehabilitation program was applied in both groups, combined with the evaluation using the clinical objective examination, subjective satisfaction of patients and the American Orthopaedic Foot and Ankle Society (AOFAS) scores. There was significant difference between group A and group B in the recovery time to normal motion ranges (P<0.05). The average AOFAS score of group A was higher more than (P<0.05). In addition, patients from the two groups did not suffer from cutaneous sensory disturbance of the dorsum of foot due to sural nerve injury, or no deep venous thrombosis. Except for 1 patient with deep infection, all patients recovered to normal motion ranges. The overall curative effect of modified medial arc incision of Achilles tendon is superior to traditional straight incision in the treatment of old Achilles tendon rupture, which is conducive to the early recovery to normal motion ranges before injury.
View Article and Find Full Text PDF

Download full-text PDF

Source
May 2020

Numerical simulation of transport and adhesion of thermogenic nano-carriers in microvessels.

Soft Matter 2020 Dec 14;16(45):10345-10357. Epub 2020 Oct 14.

School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.

Externally triggered thermogenic nanoparticles (NPs) are potential drug carriers and heating agents for drug delivery and hyperthermia. A good understanding of the transport and adhesion behaviors of NPs in microvessels is conducive to improving the efficiency of NP-mediated treatment. Given the thermogenesis of NPs and interactions of NP-blood flow, NP-NP, NP-red blood cell (RBC) and ligand-receptor, the movement of NPs in blood flow was modeled using a hybrid immersed boundary and coupled double-distribution-function lattice Boltzmann method. Results show that the margination probability of NPs toward the vessel wall was evidently increased by NP thermogenesis owing to the noticeable variation in blood flow velocity distribution, thereby enhancing their adhesion to the target region. NP-RBC collision can promote NP movement to the acellular layer in microvessels to increase the NP adhesion rate. The number of adhered smaller NPs was larger than that of the larger NPs having the same ligand density due to the enhancement of Brownian force although their adhesion was relatively less firm. Compared with the NPs with a regular shape, the irregularly shaped NPs can adhere to the vessel wall more readily and strongly as a result of the higher turbulence levels caused by NP-blood flow interaction and relatively higher ligand density, which led to a higher rate of NP adhesion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/d0sm01448fDOI Listing
December 2020

Peptide-Based Nanoparticles Mimic Fibrillogenesis of Laminin in Tumor Vessels for Precise Embolization.

ACS Nano 2020 06 19;14(6):7170-7180. Epub 2020 May 19.

CAS Center for Excellence in Nanoscience, CAS Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology (NCNST), No. 11 Beiyitiao, Zhongguancun, Beijing 100190, China.

Cancer therapeutic strategies based on angiogenesis attract great attention from fundamental and clinical research. Blocking oxygen and nutrition supply to tumor cells could inhibit the growth of tumors based on occlusion of blood vessels in the tumor. Herein, we report a dual-responsive peptide-based nanoparticle, mimicking the laminin fibrillogenesis specifically and highly efficiently in tumor vessels, resulting in the blockage of tumor vessels and the growth inhibition of tumors. The laminin mimic peptide (LMMP) is designed with a fibrillation sequence, a pH-responsive sequence, and a targeting sequence. The LMMP in nanoformulations is delivered to blood vessels in the tumors, where the microenvironment (pH and microthrombus) enable LMMP to process laminin fibrillogenesis, constructing fibrous networks. The laminin-like fibrous networks capture red blood cells , forming occlusion specifically in the tumor blood vessels to inhibit the growth of the tumor.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsnano.0c02110DOI Listing
June 2020

Measurement of the Thermophysical Properties of Anisotropic Insulation Materials with Consideration of the Effect of Thermal Contact Resistance.

Materials (Basel) 2020 Mar 17;13(6). Epub 2020 Mar 17.

School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.

A novel method involving the effect of thermal contact resistance (TCR) was proposed using a plane heat source smaller than the measured samples for improving measurement accuracy of the simultaneous determination of in-plane and cross-plane thermal conductivities and the volumetric heat capacity of anisotropic materials. The heat transfer during the measurement process was mathematically modeled in a 3D Cartesian coordinate system. The temperature distribution inside the sample was analytically derived by applying Laplace transform and the variables separation method. A multiparameter estimation algorithm was developed on the basis of the sensitivity analysis of the parameters to simultaneously estimate the measured parameters. The correctness of the algorithm was verified by performing simulation experiments. The thermophysical parameters of insulating materials were experimentally measured using the proposed method at different temperatures and pressures. Fiber glass and ceramic insulation materials were tested at room temperature. The measured results showed that the relative error was 1.6% less than the standard value and proved the accuracy of the proposed method. The TCRs measured at different pressures were compared with those obtained using the steady-state method, and the maximum deviation was 8.5%. The thermal conductivity obtained with the contact thermal resistance was smaller than that without the thermal resistance. The measurement results for the anisotropic silica aerogels at different temperatures and pressures revealed that the thermal conductivity and thermal contact conductance increased as temperature and pressure increased.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ma13061353DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7143132PMC
March 2020

Eulerian-Eulerian Numerical Study of the Flue Gas Desulfurization Process in a Semidry Spouted Bed Reactor.

ACS Omega 2020 Feb 13;5(7):3282-3293. Epub 2020 Feb 13.

School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, China.

The Eulerian-Eulerian two-fluid model (TFM) in conjunction with kinetic theory of granular flows (KTGF) was used for analyzing water vaporization and the semidry flue gas desulfurization process in a two-dimensional powder-particle spouted bed (PPSB). In an environment with high-temperature gas, desulfurization slurry is wrapped on the surface of moving particles and evaporated, along with the application of the user defined function (UDF) method to accomplish water heat and mass transfer by considering evaporation in the simulation process. The simulation results revealed that the best mass- and heat-transfer effect of each phase can be found in the outer annulus and the near spout region, both of which are also the main areas where water vaporization occurs. The rate of desulfurization products decreases with the increase in inlet gas temperature as the water vaporization rate increases. The volume fraction of desulfurization reaction products decreases with the increase in inlet flue gas temperature. Compared with other working conditions, the highest desulfurization efficiency reaches 84% when the inlet flue gas temperature is 480 K. The change of the desulfurization product rate with the radial distance is the same under different superficial gas velocities, with the peak desulfurization efficiency appearing in the annulus. The optimal operating parameter for the desulfurization process is available in PPSB, and the desulfurization efficiency and gas handling capacity reach the best result when the superficial gas velocity equals 1.2 U.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsomega.9b03361DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7045319PMC
February 2020

2 Hz EA Reduces Heroin Withdrawal-Induced Hyperalgesia and Heroin Relapse by Downregulating P2X3 Receptors in DRG Neurons.

Biomed Res Int 2019 24;2019:1873859. Epub 2019 Dec 24.

School of Physical Education, Jianghan University, Wuhan 430056, China.

Electroacupuncture (EA) has effective analgesic effects. Our previous study demonstrated that the upregulation of P2X3 receptors in the dorsal root ganglia (DRG) might participate in heroin withdrawal-induced hyperalgesia. The aim of this study is to further explore whether 2 Hz EA reduces heroin relapse associated with its analgesic effect and whether P2X3 receptors in the DRG are involved in this process. 2 Hz EA was adopted to treat the heroin SA rats in the present study. Heroin-seeking and pain sensitivity were evaluated. The expression of P2X3 receptors in the DRG was detected. Our results showed that compared with the control group, the reinstatement, thermal hyperalgesia, and mechanical allodynia of the heroin-addicted group were increased significantly. The expression of P2X3 receptors in the DRG was increased markedly. After being treated using 2 Hz EA, reinstatement was reduced, hyperalgesia was decreased, and the upregulated expression of P2X3 receptors in the DRG had decreased significantly compared to that in the heroin-addicted group. Consequently, our results indicated that 2 Hz EA was an effective method for treating heroin-induced hyperalgesia and helping prevent relapse, and the potential mechanism might be related to the downregulation of P2X3 receptor expression in the DRG.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2019/1873859DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6944962PMC
July 2020

Continuous nerve block versus single-shot nerve block for total knee arthroplasty: a meta-analysis from randomized controlled trials.

Minerva Anestesiol 2020 Feb 4;86(2):205-216. Epub 2019 Dec 4.

Department of Anesthesia, The General Hospital of Western Theater Command, Chendu, China -

Introduction: This meta-analysis aims to determine whether continuous nerve block (CNB) provides better pain relief and functional recovery than single-shot nerve block (SSNB) after total knee arthroplasty (TKA).

Evidence Acquisition: Embase, PubMed, and the Cochrane Library databases were comprehensively searched. Randomized controlled trials (RCTs) with a modified Jadad Score ≥4 comparing CNB with SSNB in patients after TKA were enrolled in our meta-analysis. The primary outcomes were visual analogue scale (VAS) pain score and morphine consumption. The secondary outcomes were distance able to ambulate, complications and length of hospital stay. Review Manager 5.3 for Windows was used to analyze the extracted data.

Evidence Synthesis: Two RCTs that compared continuous adductor canal block (ACB) with single-shot ACB, and four RCTs that compared continuous femoral nerve block (FNB) with single-shot FNB were included in our meta-analysis. There were no significant differences in VAS scores at rest for 12 hours (P=0.44), 24 hours (P=0.15) and 48 hours (P=0.16) postoperatively, VAS scores on activity for 24 hours (P=0.15) and 48 hours (P=0.23), total opioid consumption at 12 hours (P=0.20), 24 hours (P=0.25) and 48 hours (P=0.41), distance walked at 24 hours (P=0.58) and 48 hours (P=0.93), nausea and vomiting at 24 hours (P=0.18) and 48 hours (P=0.62), and length of hospital stay (P=0.71) between the CNB and SSNB groups.

Conclusions: CNB and SSNB have similar effects on pain relief, complications and functional recovery in patients receiving TKA. The optimal analgesic regimen for patients after TKA needs further identification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.23736/S0375-9393.19.13842-4DOI Listing
February 2020

Membrane TLR9 Positive Neutrophil Mediated MPLA Protects Against Fatal Bacterial Sepsis.

Theranostics 2019 14;9(21):6269-6283. Epub 2019 Aug 14.

Department of Molecular Biology, College of Basic Medical Sciences Jilin University, Changchun 130021, China.

Sepsis is a major cause of patient mortality and morbidity from bacterial infections. Although neutrophils are known to be important in the development of sepsis, how distinctive neutrophil subtypes regulate inflammatory processes involved in septicemia remains unclear. Preconditioning protects organisms against subsequent higher-dose exposures to the same, or even different, stimuli. Several studies have reported various effects of preconditioning on immune cells. However, the detailed mechanisms underlying neutrophil-mediated protection through preconditioning in sepsis remain unknown. : Flow cytometry was conducted to sort the mice peritoneal lavage cells and the blood samples from patients with sepsis. Western blotting and ELISA were carried out to elucidate the expression of TLR9 signal transduction pathway proteins. Histological analysis was used to assess the effect of InP on intestine and liver structure in and mice. Fluorescence microscopy, Co-IP, and FRET were carried out to determine the association of TLR9 with Cav-1. : We show that membrane toll-like receptor-9 positive (mTLR9) neutrophils exert a protective effect against fatal bacterial infections through the process of inflammatory preconditioning (InP). InP, which occurs in the setting of a low-dose bacterial challenge, active ingredient is Monophosphoryl lipid A (MPLA), triggers the membrane translocation of TLR9 from the neutrophil cytosol, where it binds to Cav-1. Our findings showed that InP enables TLR9 to facilitate MyD88-mediated TRAF3 and IRF3 signal transduction. Depletion of either TLR9 or Cav-1 largely eliminates the neutrophil-mediated InP effect in sepsis models and . Further, examination of clinical samples from patients with sepsis showed that clinical outcomes and likelihood of recovery are closely correlated with mTLR9 and Cav-1 expression in circulating neutrophils. : These results demonstrate that the TLR9-Cav-1 axis is a critical signaling pathway involved in the regulation of neutrophil-dependent MPLA mediated InP, and the presence of mTLR9 neutrophils could be an attractive indicator of clinical outcomes in bacterial sepsis that could be further explored as a potential therapeutic target.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7150/thno.37139DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6735515PMC
September 2020

Time-dependent polarized radiative transfer in an atmosphere-ocean system exposed to external illumination.

Opt Express 2019 Aug;27(16):A981-A994

Time-dependent polarized radiative transfer in an atmosphere-ocean system exposed to external illumination is numerically investigated. The specular reflection and transmission effects based on the relative refractive index between the atmosphere and water are considered. A modified Monte Carlo (MMC) algorithm combined with time shift and superposition principle, which significantly improves the computational efficiency of the traditional Monte Carlo (TMC) method, is developed to simulate the time-dependent polarized radiative transfer process. The accuracy and computational superiority of the MMC for polarized radiative transfer in the atmosphere-ocean system are validated, and the time-resolved polarized radiative signals are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OE.27.00A981DOI Listing
August 2019

Non-target Effects of Naphthalene on the Soil Microbial Biomass and Bacterial Communities in the Subalpine Forests of Western China.

Sci Rep 2019 07 8;9(1):9811. Epub 2019 Jul 8.

Institute of Ecology & Forestry, Sichuan Agricultural University, Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Alpine Forest Ecosystem Research Station, Soil and Water Conservation and Desertification Control Key Laboratory of Sichuan Province, Chengdu, 611130, China.

Naphthalene is a biocide of soil fauna, particularly of soil arthropods, that has been widely applied to test the functional roles of soil fauna in soil processes. However, whether the use of naphthalene to expel soil fauna has a non-target effect on soil bacteria in subalpine forests remains unclear. We conducted a naphthalene treatment experiment to explore the effects of naphthalene on the soil bacterial community in subalpine forest soil. The results suggested that naphthalene treatment (at 100 g.m per month) significantly increased the abundances of total bacterial, gram-positive bacterial and gram-negative bacterial phospholipid fatty acids (PLFA) and did not change the microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) or MBC/MBN ratio. Moreover, a total of 1038 operational taxonomic units (OTUs) were detected by Illumina MiSeq sequencing analysis. Proteobacteria, Actinobacteria, and Acidobacteria Chloroflexi were the dominant phyla, and Bradyrhizobium was the most abundant genus. The naphthalene treatment did not affect soil bacterial diversity or community structure. Overall, these results demonstrated that the naphthalene treatment had non-target effects on the active bacterial community abundance but not the soil bacterial community structure. Thus, the non-target effects of naphthalene treatment should be considered before using it to expel soil fauna.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-46394-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6614484PMC
July 2019

A Simulation Study on the Interaction Between Pollutant Nanoparticles and the Pulmonary Surfactant Monolayer.

Int J Mol Sci 2019 Jul 4;20(13). Epub 2019 Jul 4.

School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.

A good understanding of the mechanism of interaction between inhaled pollutant nanoparticles (NPs) and the pulmonary surfactant monolayer is useful to study the impact of fine particulate matter on human health. In this work, we established coarse-grained models of four representative NPs with different hydrophilicity properties in the air (i.e., CaSO, C, SiO, and CHO NPs) and the pulmonary surfactant monolayer. Molecular dynamic simulations of the interaction during exhalation and inhalation breathing states were performed. The effects of NP hydrophilicity levels, NP structural properties, and cholesterol content in the monolayer on the behaviors of NP embedment or the transmembrane were analyzed by calculating the changes in potential energy, NP displacement, monolayer orderliness, and surface tension. Results showed that NPs can inhibit the ability of the monolayer to adjust surface tension. For all breathing states, the hydrophobic C NP cannot translocate across the monolayer and had the greatest influence on the structural properties of the monolayer, whereas the strongly hydrophilic SiO and CHO NPs can cross the monolayer with little impact. The semi-hydrophilic CaSO NP can penetrate the monolayer only during the inhalation breathing state. The hydrophilic flaky NP shows the best penetration ability, followed by the rod-shaped NP and spherical NP in turn. An increase in cholesterol content of the monolayer led to improved orderliness and decreased fluidity of the membrane system due to enhanced intermolecular forces. Consequently, difficulty in crossing the monolayer increased for the NPs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms20133281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6651701PMC
July 2019

Effects of naphthalene on soil fauna abundance and enzyme activity in the subalpine forest of western Sichuan, China.

Sci Rep 2019 02 26;9(1):2849. Epub 2019 Feb 26.

Institute of Ecology & Forestry, Sichuan Agricultural University, Forestry Ecological Engineering in Upper Reaches of Yangtze River Key Laboratory of Sichuan Province, Alpine Forest Ecosystem Research Station, Soil and Water Conservation and Desertification Control Key Laboratory of Sichuan Province, Chengdu, 611130, China.

Naphthalene has been widely used to study the role of soil fauna, but its potential non-target effects on soil enzyme activity remain unknown in subalpine forests. We added naphthalene for two years and determined the effect of such additions on the abundance of soil fauna and soil enzyme activities (β-glucosidase, cellobiohydrolase, invertase, peroxidase, polyphenol oxidase, N-acetyl-β-D-glucosaminidase, leucine arylamidase, urease, nitrate reductase and nitrite reductase) in a subalpine forest. Naphthalene could efficiently suppress the individual density and population of soil fauna in situ. The individual density and number of groups were decreased by 72.6-84.8% and 15.0-28.0%, respectively. Naphthalene significantly affected the activities of β-glucosidase, cellobiohydrolase, polyphenol oxidase, N-acetyl-β-D-glucosaminidase, leucine arylamidase and nitrite reductase and the activity increased in the first litter peak of naphthalene addition, and decreased at the later. The activities of β-glucosidase, cellobiohydrolase, polyphenol oxidase, peroxidase, N-acetyl-β-D-glucosaminidase, leucine arylamidase and nitrite reductase showed a negative correlation with the soil microbial PLFAs. Conversely, the activities of invertase, urease and nitrate reductase were positively correlated with the soil microbial PLFAs. Our results suggest that naphthalene is an effective method to reduce soil fauna in subalpine forest. The enzyme activity was influenced by soil fauna and microbial PLFAs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-019-39603-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391496PMC
February 2019

Litter removal reduced soil nitrogen mineralization in repeated freeze-thaw cycles.

Sci Rep 2019 02 14;9(1):2052. Epub 2019 Feb 14.

Long-Term Research Station of Alpine Forest Ecosystems, Key Laboratory of Ecological Forestry Engineering, Institute of Ecology and Forestry, Sichuan Agricultural University, Chengdu, 611130, China.

Repeated freeze-thaw cycles (FTCs) can alter the relationships between plant litter and soil nitrogen (N) mineralization in subalpine ecosystems, but little information is available about the underlying mechanisms. Therefore, a controlled soil incubation experiment was carried out to study the effects of litter removal on soil N mineralization during FTCs, and the results indicated that FTCs promoted soil N mineralization more than the continuously frozen or nonfrozen condition did. Litter removal promoted soil ammonium N (NH-N) and dissolved organic N (DON) as well as the cumulative N mineralization (CNM) and ammonification, but it reduced the soil microbial biomass N (MBN) in the early stage of FTCs. With an increasing number of FTCs, litter removal significantly reduced the CNM but increased the soil MBN. The modified first-order kinetics model was verified under incubation conditions and predicted a lower soil N mineralization rate in FTCs with litter removal. In addition, the dominant factor impacting soil N mineralization was soil NO-N, and soil MBN had a greater influence on soil N mineralization when litter remained than when it was removed. These results further clarify the mechanism driving the effect of plant residues on soil N cycling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-38431-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376039PMC
February 2019

Factors Influencing Aggregation of Gold Nanoparticles in Whole Blood.

J Nanosci Nanotechnol 2019 Jul;19(7):3762-3771

School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China.

Nanoparticles (NPs) have been widely studied and shown significant potential in biological and medical applications owing to their unique physicochemical properties. However, aggregation will severely restrict NP use by causing a change in biological effects of related NPs. This study experimentally investigated the aggregation behaviors of AuNPs in deionized (DI) water and whole blood by transmission electron microscopy and dynamic light scattering. The effects of NP size, NP concentration, temperature, and surface modification were analyzed and experimental results were rationalized by the extended Derjaguin-Landau-Verwey-Overbeek theory. The results show the advantage of selecting relatively large NP size and low NP concentration within the applicable range in achieving good dispersion. Higher temperature can enhance NP aggregation both in terms of aggregation rate and in aggregate size. In whole blood, the percentage of the AuNPs over 200 nm increased by more than threefold from 21 °C to 57 °C. Compared with the NP size and concentration, temperature most significantly affected NP aggregation. NP concentration exerts a relatively slighter influence than temperature and NP size when it changes within a relatively narrow range. The degree of NP aggregation in whole blood is higher than that in DI water as the ions and proteins will neutralize the electric charge and decrease the electrostatic force between NPs. Hydrophilic surface modification can effectively inhibit NP aggregation by increasing the electrostatic force, weakening the hydrophobic force, and preventing the Au-protein assembly. However, NP aggregation of hydrophilic polyethylene glycol-modified AuNPs was still observed in whole blood.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1166/jnn.2019.16315DOI Listing
July 2019

A further assessment of a role for Toll-like receptor 4 in the reinforcing and reinstating effects of opioids.

Behav Pharmacol 2020 04;31(2&3):186-195

Psychobiology Section, Department of Health and Human Services, Molecular Neuropsychiatry Research Branch, Intramural Research Program.

The Toll-like receptor 4 (TLR4) antagonists, (+)-naloxone and (+)-naltrexone, have been reported to decrease self-administration of opioids in rats and to reduce other preclinical indicators of abuse potential. However, under the self-administration conditions studied, the effects of TLR4 antagonists were not reinforcer selective, questioning the involvement of those receptors and their mediated inflammatory response specifically in opioid abuse. The objectives of the current study were to further characterize the reinforcer specificity of TLR4 antagonism in opioid self-administration and to explore its effects in a preclinical model of craving/relapse. The TLR4 antagonist (+)-naltrexone decreased responding in rats trained to self-administer the µ-opioid receptor agonist remifentanil, but with a potency that was not significantly different from that observed in another group of subjects in which responding was maintained by food reinforcement. Responding reinstated by heroin injection was decreased by (+)-naltrexone; however, a similar reduction was not reproduced with the administration of another TLR4 antagonist, lipopolysaccharide from Rhodobacter sphaeroides, administered into the NAcc shell. Thus, TLR4 antagonists lacked reinforcer selectivity in reducing opioid self-administration and were not uniformly effective in a model of craving/relapse, suggesting limitations on the development of (+)-naltrexone or TLR4 antagonists as treatments for opioid abuse.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/FBP.0000000000000474DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6685775PMC
April 2020

Nitrogen additions stimulate litter humification in a subtropical forest, southwestern China.

Sci Rep 2018 12 3;8(1):17525. Epub 2018 Dec 3.

Long-term Research Station of Alpine Forest Ecosystems, Institute of Forest & Ecology, Sichuan Agricultural University, Chengdu, 611130, China.

Despite the importance of nitrogen (N) deposition for soil biogeochemical cycle, how N addition affects the accumulation of humic substances in decomposing litter still remains poorly understood. A litterbag experiment was conducted to assess the potential effects of N addition (0 kg·N·ha·year, 20 kg·N·ha·year and 40 kg·N·ha·year) on mass remaining and humification of two leaf litter (Michelia wilsonii and Camptotheca acuminata) in a subtropical forest of southwestern China. After one year of decomposition, litter mass was lost by 38.1-46.5% for M. wilsonii and 61.7-74.5% for C. acuminata, respectively. Humic substances were declined by 12.1-23.8% in M. wilsonii and 29.1-35.5% in C. acuminata, respectively. Nitrogen additions tended to reduce mass loss over the experimental period. Moreover, N additions did not affect the concentrations of humic substances and humic acid in the early stage but often increased them in the late stage. The effect of N addition on the accumulation of humic substances was stronger for C. acuminate litter than in M. wilsonii litter. Litter N and P contents showed positive correlations with concentrations of humic substances and fulvic acid. Our results suggest that both litter quality and season-driven environmental changes interactively mediate N impacts on litter humification. Such findings have important implications for carbon sequestration via litter humification in the subtropical forest ecosystems experiencing significant N deposition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-35720-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6277447PMC
December 2018

Immobilization of heavy metals during aquatic and terrestrial litter decomposition in an alpine forest.

Chemosphere 2019 Feb 25;216:419-427. Epub 2018 Oct 25.

Long-term Research Station of Alpine Forest Ecosystems, Provincial Key Laboratory of Ecological Forestry Engineering, Institute of Ecology and Forestry, Sichuan Agricultural University, 211 Huimin Road, Wenjiang District, Chengdu, 611130, Sichuan, China. Electronic address:

Plant litter decomposition is an important pathway of heavy metal cycling in forested soil and watershed ecosystems globally, but is so far an overlooked aspects in the existing literature. To investigate the temporal dynamics of heavy metals in decomposing litter, we conducted a two-year field experiment using litterbag method across aquatic and terrestrial ecosystems in an alpine forest on the eastern Tibetan Plateau. Using multigroup comparisons of structural equation modeling with different litter mass-loss intervals, we assessed the direct and indirect effects of several biotic and abiotic factors on the release rates of lead (Pb), cadmium (Cd), and chromium (Cr). Results suggested that both the concentrations and amounts of Pb, Cd, and Cr increased during litter decomposition regardless of ecosystem type and litter species, showing an immobilization pattern. The release rates of Pb, Cd, or Cr shared a common hierarchy of drivers across aquatic and terrestrial ecosystems, with environmental factors and initial litter quality having both direct and indirect effects, and the effects of initial litter quality gained importance in the late decomposition stages. However, litter chemical dynamics and microbial diversity index have significant effects on release rates throughout the decomposition process. Our results are useful for better understanding heavy metal fluxes in aquatic and terrestrial ecosystems, and for predicting anthropogenic heavy metal pollution impacts on ecosystems. In addition, our results indicated that not only spatial but also temporal variability should be taken into consideration when addressing heavy metal dynamics accompanying litter decomposition process.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2018.10.169DOI Listing
February 2019

Novel self-adaptive boat-shaped complexes with a tetraphosphine ligand.

Dalton Trans 2018 Oct;47(38):13689-13695

State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, Department of Chemistry, Nankai University, Tianjin 300071, P. R. China.

A series of novel boat-shaped host-guest complexes were designed and synthesized by the combination of a new calixarene fragment-based tetraphosphine ligand L with group 11 metal salts Cu(MeCN)4ClO4 and AgNO3 in a self-assembly process, and by the following anion exchange reactions of complex 1 with sodium p-toluenesulfonate, AcONa, PhCO2Na and sodium 9-anthrylcarboxylate. The host with a novel boat-shaped cavity is capable of self-adaptive encapsulation of various anions of different sizes through M(i)-O coordinations and CHπ interactions between the host and guest anion. The DFT calculations confirmed that the CHπ interaction played a vital role in the self-adaptive phenomenon in complexes 4-6.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c8dt02498gDOI Listing
October 2018

Abuse liability of mitragynine assessed with a self-administration procedure in rats.

Psychopharmacology (Berl) 2018 Oct 23;235(10):2823-2829. Epub 2018 Jul 23.

Psychobiology Section, Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, 251 Bayview Blvd., Baltimore, MD, 21224, USA.

Rationale: Substantial use of the plant kratom for psychoactive effects has driven interest in its abuse liability. Several place conditioning studies suggest abuse liability of the active ingredient mitragynine, though studies of its self-administration have not been published.

Methods: Binding of mitragynine to rat brain mu, kappa, and delta opioid receptors was compared to that for heroin and morphine. Self-administration of mitragynine, heroin, methamphetamine, or saline was assessed during single-session substitutions in rats trained to self-administer methamphetamine (0.022 mg/kg/injection, i.v.) during 1-h daily sessions.

Results: Mitragynine had > 2- or ~ 16-fold greater affinity for the mu opioid receptor than, respectively, for kappa or delta opioid receptors. Its affinity for the mu receptor was ~ 200-fold less than that for morphine. In rats trained to self-administer methamphetamine, saline substitutions significantly decreased the number of responses, whereas different doses of methamphetamine (0.002-0.068 mg/kg/injection) or heroin (0.001-0.03 mg/kg/injection) maintained self-administration with maximal responding at 0.022 or 0.01 mg/kg/injection, respectively. In contrast, no dose of mitragynine maintained response rates greater than those obtained with saline. Presession mitragynine treatment (0.1 to 3.0 mg/kg) decreased response rates maintained by heroin but had little effect on responding maintained by methamphetamine across the same range of doses.

Conclusions: These results suggest a limited abuse liability of mitragynine and potential for mitragynine treatment to specifically reduce opioid abuse. With the current prevalence of opioid abuse and misuse, it appears currently that mitragynine is deserving of more extensive exploration for its development or that of an analog as a medical treatment for opioid abuse.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00213-018-4974-9DOI Listing
October 2018

Does foliar nutrient resorption regulate the coupled relationship between nitrogen and phosphorus in plant leaves in response to nitrogen deposition?

Sci Total Environ 2018 Dec 19;645:733-742. Epub 2018 Jul 19.

Long-term Research Station of Alpine Forest Ecosystems, Provincial Key Laboratory of Ecological Forestry Engineering, Institute of Ecology and Forestry, Sichuan Agricultural University, 211 Huimin Road, Wenjiang District, Chengdu 611130, China.

Nutrient resorption from senescing leaves is an important process of internal nutrient cycling in plants, but the patterns of nutrient resorption and the coupled relationship between nitrogen (N) and phosphorus (P) in plant leaves as affected by N deposition remain unclear. We analysed the effects of N addition on the nutrient resorption and coupled relationship between N and P in plant leaves under different nutrient-limited conditions based on a global meta-analysis. Globally, the mean N resorption efficiency (NRE) and P resorption efficiency (PRE) under natural conditions were 47.4% and 53.6%, respectively, which were significantly regulated by geographical and climatic factors as well as plant characteristics. Furthermore, N addition significantly decreased the NRE by 13.3% but slightly affected the PRE on a global scale, and N addition rates and latitude directly and negatively affected the effects of N addition on NRE. Specifically, N addition significantly decreased the NRE under all nutrient-limited conditions, while it had negative, positive, and neutral effects on the PRE under N-limited, P-limited, and N and P-co-limited conditions, respectively. Moreover, the relationships between N and P in green and senesced leaves were tightly coupled under different nutrient-limited conditions in natural ecosystems. However, N addition significantly weakened the relationships between N and P concentrations in green leaves but slightly affected the relationship in senesced leaves, which were mainly modulated by the effects of N addition on nutrient resorption efficiency, especially NRE. These results highlight that nutrient-limited conditions determine the response of nutrient resorption to N deposition and emphasize the effect of nutrient resorption regulation on the coupling of N and P responses to N enrichment. The findings are important for understanding plant nutrient use strategies and the mechanisms underlying the stoichiometric coupling of N and P in response to climate change, and can be used in global biogeochemical models.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2018.07.186DOI Listing
December 2018

Temporal dynamics of phosphorus during aquatic and terrestrial litter decomposition in an alpine forest.

Sci Total Environ 2018 Nov 17;642:832-841. Epub 2018 Jun 17.

Long-term Research Station of Alpine Forest Ecosystems, Provincial Key Laboratory of Ecological Forestry Engineering, Institute of Ecology and Forestry, Sichuan Agricultural University, Chengdu 611130, China. Electronic address:

Plant litter decomposition in forested soil and watershed is an important source of phosphorus (P) for plants in forest ecosystems. Understanding P dynamics during litter decomposition in forested aquatic and terrestrial ecosystems will be of great importance for better understanding nutrient cycling across forest landscape. However, despite massive studies addressing litter decomposition have been carried out, generalizations across aquatic and terrestrial ecosystems regarding the temporal dynamics of P loss during litter decomposition remain elusive. We conducted a two-year field experiment using litterbag method in both aquatic (streams and riparian zones) and terrestrial (forest floors) ecosystems in an alpine forest on the eastern Tibetan Plateau. By using multigroup comparisons of structural equation modeling (SEM) method with different litter mass-loss intervals, we explicitly assessed the direct and indirect effects of several biotic and abiotic drivers on P loss across different decomposition stages. The results suggested that (1) P concentration in decomposing litter showed similar patterns of early increase and later decrease across different species and ecosystems types; (2) P loss shared a common hierarchy of drivers across different ecosystems types, with litter chemical dynamics mainly having direct effects but environment and initial litter quality having both direct and indirect effects; (3) when assessing at the temporal scale, the effects of initial litter quality appeared to increase in late decomposition stages, while litter chemical dynamics showed consistent significant effects almost in all decomposition stages across aquatic and terrestrial ecosystems; (4) microbial diversity showed significant effects on P loss, but its effects were lower compared with other drivers. Our results highlight the importance of including spatiotemporal variations and indicate the possibility of integrating aquatic and terrestrial decomposition into a common framework for future construction of models that account for the temporal dynamics of P in decomposing litter.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2018.06.135DOI Listing
November 2018

The effect of canopy exchange on input of base cations in a subalpine spruce plantation during the growth season.

Sci Rep 2018 06 19;8(1):9373. Epub 2018 Jun 19.

Long-term Research Station of Alpine Forest Ecosystems, Key Laboratory of Ecological Forestry Engineering, Institute of Ecology and Forestry, Sichuan Agricultural University, Chengdu, 611130, China.

Canopy exchange is one of the most important processes involved in the internal transfer of elements in forest ecosystems. However, little information is available on how canopy exchange influences the input of base cations in subalpine forests. Therefore, the concentrations and fluxes of base cations in throughfall and stemflow were investigated from August 2015 to July 2016 (except for the frozen season) in a representative subalpine spruce plantation in the eastern Tibet Plateau. Our results showed that the mean concentrations of K, Ca, Na and Mg were higher in the stemflow than in the throughfall and precipitation. The total input fluxes of K, Ca, Na and Mg in the internal forest were lower than those in the non-forest. Moreover, the results from the canopy budget model indicated that the canopy exchange fluxes of K, Ca and Mg were higher than the dry deposition fluxes, and Ca and Mg were uptaken, whereas K was leached when precipitation passed through the canopy. Therefore, the results suggested that the input of base cations is mainly controlled by canopy exchange during precipitation in subalpine forest ecosystems, and the canopy could alter the sinks and sources of base cations from precipitation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-018-27675-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6008401PMC
June 2018