NaHS immersion alleviates the stress effect of chromium(III) on alfalfa seeds by affecting active oxygen metabolism.

OBJECTIVE: This study aimed to investigate the regulatory effects of exogenous hydrogen sulfide (H2S) on seed germination, seedling growth, and reactive oxygen species (ROS) homeostasis in alfalfa under chromium (Cr) ion (III) stress. METHODS: The effects of 0-4 mM Cr(III) on the germination and seedling growth of alfalfa were first assessed. Subsequently, following seed NaHS immersion, the influence of H2S on alfalfa seed germination and seedling growth under 2 mM Cr(III) stress was investigated, and the substance contents and enzyme activities associated with ROS metabolism were quantified. RESULTS: Compared to the control group, alfalfa plant germination was delayed under 2 mM Cr(III) stress for up to 48 h (p < 0.05). At 120 h, the total seedling length was approximately halved, and the root length was roughly one-third of the control. Treatment with 0.02-0.1 mM NaHS alleviated the delay in germination and root growth inhibition caused by 2 mM Cr(III) stress, resulting in an increased ratio of root length to hypocotyl length from 0.57 to 1 above. Additionally, immersion in 0.05 mM NaHS reduced hydrogen peroxide (H2O2) and oxygen-free radicals (O2· -) levels (p < 0.05), boosted glutathione (GSH) levels (p < 0.05), and notably enhanced catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) activities (p < 0.05) compared to the 2 mM Cr(III) stress treatment group. CONCLUSION: Seed immersion in NaHS mitigated the delay in germination and inhibition of root elongation under 2 mM Cr(III) stress. This effect is likely attributed to the regulation of intracellular ROS homeostasis and redox balance through enzymatic and non-enzymatic systems; thus, providing a potential mechanism for combating oxidative stress.

Development of metabolome extraction strategy for metabolite profiling of skin tissue.

INTRODUCTION: Changes in skin phenotypic characteristics are based on skin tissue. The study of the metabolic changes in skin tissue can help understand the causes of skin diseases and identify effective therapeutic interventions. OBJECTIVES: We aimed to establish and optimize a non-targeted skin metabolome extraction system for skin tissue metabolomics with high metabolite coverage, recovery, and reproducibility using gas chromatography/mass spectrometry. METHODS: The metabolites in skin tissues were extracted using eleven different extraction systems, which were designed using reagents with different polarities based on sequential solid-liquid extraction employing a two-step strategy and analyzed using gas chromatograph/mass spectrometry. The extraction efficiency of diverse solvents was evaluated by coefficient of variation (CV), multivariate analysis, metabolites coverage, and relative peak area analysis. RESULTS: We identified 119 metabolites and the metabolite profiles differed significantly between the eleven extraction systems. Metabolites with high abundances in the organic extraction systems, followed by aqueous extraction, were involved in the biosynthesis of unsaturated fatty acids, while metabolites with high abundances in the aqueous extraction systems, followed by organic extraction, were involved in amino sugar and nucleotide sugar metabolism, and glycerolipid metabolism. MeOH/chloroform-H2O and MeOH/H2O-chloroform were the extraction systems that yielded the highest number of metabolites, while MeOH/acetonitrile (ACN)-H2O and ACN/H2O-IPA exhibited superior metabolite recoveries. CONCLUSION: Our results demonstrated that our research facilitates the selection of an appropriate metabolite extraction approach based on the experimental purpose for the metabolomics study of skin tissue.

Nomogram to predict the presence of PSMA-negative but FDG-positive lesion in castration-resistant prostate cancer: a multicenter cohort study.

Background: PSMA-negative but FDG-positive (PSMA-/FDG+) lesion in dual-tracer (68Ga-PSMA and 18F-FDG) positron emission tomography/computed tomography (PET/CT) is associated with an unfavorable response to Lutetium-177 (177Lu)-PSMA-617. This study sought to develop both radiomics and clinical models for the precise prediction of the presence of PSMA-/FDG+ lesions in patients with castration-resistant prostate cancer (CPRC). Methods: A cohort of 298 patients who underwent dual-tracer PET/CT with a less than 5-day interval was included. The evaluation of the prognostic performance of the radiomics model drew upon the survival data derived from 40 patients with CRPC treated with 177Lu-PSMA-617 in an external cohort. Two endpoints were evaluated: (a) prostate-specific antigen (PSA) response rate, defined as a reduction exceeding 50% from baseline and (b) overall survival (OS), measured from the initiation of 177Lu-PSMA-617 to death from any cause. Results: PSMA-/FDG+ lesions were identified in 56 (18.8%) CRPC patients. Both radiomics (area under the curve [AUC], 0.83) and clinical models (AUC, 0.78) demonstrated robust performance in PSMA-/FDG+ lesion prediction. Decision curve analysis revealed that the radiomics model yielded a net benefit over the 'screen all' strategy at a threshold probability of ⩾4%. At a 5% probability threshold, the radiomics model facilitated a 21% reduction in 18F-FDG PET/CT scans while only missing 2% of PSMA-/FDG+ cases. Patients with a low estimated score exhibited significantly prolonged OS (hazard ratio = 0.49, p = 0.029) and a higher PSA response rate (75% versus 35%, p = 0.011) compared to those with a high estimated score. Conclusion: This study successfully developed two models with accurate estimations of the risk associated with PSMA-/FDG+ lesions in CRPC patients. These models held potential utility in aiding the selection of candidates for 177Lu-PSMA-617 treatment and guiding 68Ga-PSMA PET/CT-directed radiotherapy.

Predictive nomogram for PSMA-/FDG+ lesion This study developed two models with accurate estimations of the risk associated with specific lesions in prostate cancer.

Pathogenic mechanism of Eimeria tenella autophagy activation of chicken embryo cecal epithelial cells induced by Eimeria tenella.

Eimeria tenella mainly invades and develops into cecal epithelial cells of chickens, resulting in cecal epithelial cell damage. Infectious intracellular pathogens possibly act by influencing the autophagy process after invading cells. The interaction between E. tenella and the autophagy of host cells was explored by infecting E. tenella with chick embryo cecal epithelial cells. Transmission electron microscopy, laser confocal microscopy, and Western blot analysis were used to demonstrate that E. tenella infection could induce autophagy in host cells. Results showed that infection with E. tenella induced the formation of autophagosomes in cells. The expression of ATG 5, Beclin-1, and LC3B-II proteins were significantly (P < 0.01) increased after E. tenella infected host cells. Expression of p62 protein levels were significantly (P < 0.01) decreased in host cells infected with E. tenella. Chloroquine (CQ) significantly (P < 0.01) increased the expression levels of LC3B-II and P62 in E. tenella-infected host cells. Rapamycin (RAPA) induced autophagy in host cells, thus reducing the intracellular infection of E. tenella. By contrast, the infection rate of E. tenella increased in cells treated with 3-Methyladenine (3-MA). Hence, E. tenella sporozoite infection could induce autophagy activation in chick embryo cecal epithelial cells, and enhanced autophagy could reduce the infection rate of E. tenella.

Role of EtMIC4 EGF-like in regulating the apoptosis of Eimeria tenella host cells via the EGFR pathway.

This study aimed to explore the role and key point of EtMIC4 EGF-like recombinant protein in regulating the apoptosis of Eimeria tenella host cells via the epidermal growth factor receptor (EGFR) pathway. The cells were treated with EtMIC4 EGF-like protein, EGFR-specific siRNA, or both. Infection and apoptosis rates as well as dynamic changes in the key genes and proteins of the EGFR signaling pathway in the host cells were determined. Results showed that the E. tenella and EtMIC4 EGF-like group had the highest infection rate (P < 0.01). In cells treated with EtMIC4 EGF-like for 4 to 24 h, the apoptosis rate was significantly decreased (P < 0.01) and the relative mRNA expression and protein phosphorylation levels of EGFR, protein kinase B (AKT), and extracellular regulated protein kinases (ERK) were significantly increased (P < 0.01). In E. tenella sporozoites infected for 4 to 96 h, the rate of host cell apoptosis induced by E. tenella infection was significantly (P < 0.01) reduced by EtMIC4 EGF-like. The relative mRNA expression and protein phosphorylation levels of EGFR, AKT, and ERK in the host cells of E. tenella + EtMIC4 EGF-like group were significantly increased (P < 0.01). These results indicated that E. tenella could activate the EGFR pathway through EtMIC4 EGF-like and regulate the expression of key genes in the AKT and ERK signaling pathways, thereby inhibiting cell apoptosis.

GC-TOF/MS-Based Metabolomics for Comparison of Volar and Non-Volar Skin Types.

Skin has heterogenous identities on different body sites despite similar cellular compositions. There are two types of skin, volar (palmoplantar) and non-volar (dorsal), which are characterized by epidermal thickness, pigmentation, and presence of hair follicles. However, the mechanisms underlying the development of these different skin types remain unclear. To investigate these, we profiled the cellular metabolites of volar and non-volar skin in mice using gas chromatography-time-of-flight/mass spectrometry (GC-TOF/MS), and further assessed the metabolic differences between them. In total, 96 metabolites from both volar and non-volar skin of mice were identified using the BinBase database system. Metabolomics analysis revealed important differences associated with amino acid metabolism (phenylalanine, tyrosine, and tryptophan biosynthesis; aspartate and glutamate metabolism), sugar metabolism (pentose phosphate pathway), and nucleotide metabolism (pyrimidine metabolism) in volar skin. Fifty metabolites were identified as potential biomarkers differentiating the physiological characteristics of these skin types. Of these, nine were highly increased whereas 41 were significantly decreased in volar skin compared with those in non-volar skin. Overall, these results provide valuable information for understanding the metabolic differences between volar and non-volar skin.

Efficient optical reservoir computing for parallel data processing.

We propose and experimentally demonstrate an optical reservoir computing system in free space, using second-harmonic generation for nonlinear kernel functions and a scattering medium to enhance reservoir nodes interconnection. We test it for one-step and multi-step predication of Mackey-Glass time series with different input-mapping methods on a spatial light modulator. For one-step prediction, we achieve 1.8 × 10-3 normalized mean squared error (NMSE). For the multi-step prediction, we explore two different mapping methods: linear-combination and concatenation, achieving 16-step prediction with NMSE as low as 3.5 × 10-4. Robust and superior for multi-step prediction, our approach and design have potential for parallel data processing tasks such as video prediction, speech translation, and so on.

The role of Ca2+ in the injury of host cells during the schizogenic stage of E. tenella.

Cecal epithelial cell damage is a key factor in host injure during the development of E. tenella. The intracellular free Ca2+ of the host cell is closely related to the invasion, development and proliferation of intracellular parasites, and cell damage. To determine the relationship between Ca2+ and host cell damage in the schizogenic stage of E. tenella, we established a chick embryo cecal epithelial cells model of E. tenella infection. Fluorescence staining, flow cytometry, transmission electron microscopy, inhibition and blocking experiments were used to detect the damage effect and mechanism of host cells during the schizogenic stage of E. tenella. The results showed that the host cells cytoskeletal remodeling, cell and organelle structure was destroyed, and apoptosis and necrosis were increased during the schizont stage of E. tenella. Furthermore, the above-mentioned effects of the schizogenic stage of E. tenella on cells can be alleviated by reducing the intracellular Ca2+ concentration in the host cells. These observations indicate that the effect of host cell injury was closely related to Ca2+ during schizont stage of E. tenella.

177Lu-PSMA-I&T Radioligand Therapy for Treating Metastatic Castration-Resistant Prostate Cancer: A Single-Centre Study in East Asians.

Purpose: There is increasing evidence for convincing efficacy and safety of 177Lu-labled prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (PRLT) for metastatic castration-resistant prostate cancer (mCRPC). However, data are not available regarding the feasibility of 177Lu-labled PSMA-targeted RLT in East Asians. The present study summarized the first experience with 177Lu-PSMA-I&T therapy for mCRPC in China. Methods: Forty consecutive patients with mCRPC were enrolled from December 2019 to September 2021. Eligible patients received 177Lu-PSMA-I&T RLT at intervals of 8-12 weeks. Toxicity was assessed based on standardized physicians' reports and the Common Toxicity Criteria for Adverse Events criteria. Response to PRLT was evaluated according to the changes of prostate specific antigen (PSA) response and imaging response. Quality of life (QOL), Karnofsky performance status (KPS) and pain (visual analogue scale, VAS) were also evaluated. The impacts of baseline parameters on the therapeutic effects were explored by univariate and multivariate logistic regression analyses. Results: All patients underwent a total of 86 cycles of 177Lu-PSMA-I&T (range: 1-5 cycles) with dosages of 3.70-14.43GBq per cycle, with a median of 8 months followed up. Six patients (15%) developed mild reversible xerostomia during follow-up, and 28 patients (70%) experienced grade 1-4 bone marrow dysfunction. Changes in PSA were assessed after therapy, accompanied by the partial response (PR) in 25 patients (62.5%), the stable disease (SD) in 5 patients (12.5%), and the progressive disease (PD) in 10 patients (25%), respectively. QOL, KPS (%) and VAS scores were improved significantly due to treatment (P<0.05). Overweight and elevated AST, ALP, and LDH were associated with poor outcomes. Conclusions: 177Lu-PSMA-I&T achieves the favourable response and well tolerance in mCRPC, which associates with not only PSA decline but also with tumor remission including lymphadenopathy and bone metastasis. We also find that patients with overweight and high AST, ALP, and LDH should be cautious to undergo the PRLT. Large-cohort studies are warranted to confirm the initial findings and elucidate the survival benefit of the treatment.

68Ga-DOTA-NT-20.3 Neurotensin Receptor 1 PET Imaging as a Surrogate for Neuroendocrine Differentiation of Prostate Cancer.

Prostate-specific membrane antigen (PSMA)-negative neuroendocrine prostate cancer (PCa) is a subtype of PCa likely to be lethal, with limited clinical diagnostic and therapeutic options. High expression of neurotensin receptor subtype 1 (NTR1) is associated with neuroendocrine differentiation of PCa, which makes NTR1 a potential target for neuroendocrine PCa. In this study, the NTR1-targeted tracer 68Ga-DOTA-NT-20.3 was synthesized, and its affinity to androgen-dependent (LNCap) and androgen-independent (PC3) xenografts was determined. Methods: 68Ga-DOTA-NT-20.3 was labeled using an automated synthesizer module, and its stability, labeling yield, and radiochemical purity were analyzed by radio-high-performance liquid chromatography. Receptor binding affinity was evaluated in NTR1-positive PC3 cells by a competitive binding assay. The biodistribution of 68Ga-DOTA-NT-20.3 in vivo was evaluated in PC3 and LNCap xenografts by small-animal PET imaging. NTR1 expression was identified by immunohistochemistry and immunofluorescence evaluation. Results: 68Ga-DOTA-NT-20.3 was synthesized successfully, with a yield of 88.07% ± 1.26%, radiochemical purity of at least 99%, and favorable stability. The NTR1 affinity (half-maximal inhibitory concentration) for 68Ga-DOTA-NT-20.3 was 7.59 ± 0.41 nM. Small-animal PET/CT of PC3 xenograft animals showed high-contrast images with intense tumor uptake, which revealed specific NTR1 expression. The tumors showed significant radioactivity (4.95 ± 0.67 percentage injected dose per gram of tissue [%ID/g]) at 1 h, which fell to 1.95 ± 0.17 %ID/g (P < 0.01, t = 8.72) after specific blockage by neurotensin. LNCap xenografts had no significant accumulation (0.81 ± 0.06 %ID/g) of 68Ga-DOTA-NT-20.3 at 1 h. In contrast, 68Ga-PSMA-11 was concentrated mainly in LNCap xenografts (8.60 ± 2.11 %ID/g), with no significant uptake in PC3 tumors (0.53 ± 0.05 %ID/g), consistent with the in vitro immunohistochemistry findings. Biodistribution evaluation showed rapid clearance from the blood and main organs (brain, heart, lung, liver, muscle, and bone), with significantly high tumor-to-liver (4.41 ± 0.73) and tumor-to-muscle (12.34 ± 1.32) ratios at 60 min after injection. Conclusion: 68Ga-DOTA-NT-20.3 can be efficiently prepared with a high yield and high radiochemical purity. Its favorable biodistribution and prominent NTR1 affinity make 68Ga-DOTA-NT-20.3 a potential radiopharmaceutical for the detection of PSMA-negative PCa and identification of neuroendocrine differentiation.

Comparison of Antioxidant Properties and Metabolite Profiling of Acer pseudoplatanus Leaves of Different Colors.

Acer pseudoplatanus (maple) is a widely grown ornamental plant. In addition to its ornamental and ecological value, it also has potentially high economic value. It is a rich source of polyphenols and exhibits antioxidant activity. However, the relationship between polyphenol content and antioxidant activity in maple leaves of different colors (green, yellow, and red) has not yet been investigated. In this study, the total polyphenol (TP), total flavonoid (TFlav), tannin (TET), chlorophyll a and b (Chl a and b), total anthocyanin (TAN), and total carotene (TAC) contents in maple leaves of different colors were evaluated. Their antioxidant activities were determined based on the inhibition of lipid oxidation, DPPH scavenging, ferric ion-reducing antioxidant power, and iron-chelating abilities. The concentrations of TP, TET, TFlav, TAN, and TAC in red maple leaves were higher than those in green and yellow maple leaves. In addition, red maple leaves showed a higher antioxidant effect than the leaves of the other two colors. We observed that antioxidant activity was positively correlated with TP, TFlav, and TAN and negatively correlated with Chl a and b. Finally, we analyzed the metabolites of the different colored (i.e., green, yellow, and red) maple leaves using gas chromatography/mass spectrometry (GC/MS) and found that the metabolite profile significantly varied between the different colors. These results suggest that red leaves are a good source of polyphenols and antioxidants and have potential use in the development of functional foods and medicinal applications.

Regulation effects of hydrogen sulfide on ascorbate-glutathione cycle in naked oat leaves under saline-alkali stress.

Saline-alkali stress is one of the common abiotic stresses for plants. Hydrogen sulfide (H2S), as a gas signal, plays an important role in driving the responses of plants to saline-alkali stress. To explore the regulating effects of H2S on the ascorbate (AsA)-glutathione (GSH) cycle in naked oat (Avena nude) under saline-alkali stress, we used sodium hydrogen sulfide (NaHS) as donor of exogenous H2S and hydroxylamine (HA) as H2S synthesis inhibitor to examine the effects of H2S on plant growth, leaf reactive oxygen species, membrane lipid peroxidation, and antioxidants and key enzymes in the AsA-GSH cycle in "Dingyou 9" variety of naked oat under saline-alkali mixed stress. Results showed that spraying 50 µmol·L-1 NaHS could alleviate the inhibition of 50 mmol·L-1 saline-alkali mixed stress on the growth of naked oats, reduce the content of superoxide anions, H2O2, malondialdehyde, oxidized ascorbate (DHA), glutathione (GSH), and oxidized glutathione (GSSG) in leaves of naked oat under saline-alkali mixed stress, increase the ratio of AsA/DHA and GSH/GSSG, but did not affect the content of reduced ascorbic acid (AsA). Spraying NaHS significantly increased the activities of key enzymes, L-galactose dehydrogenase (GalDH) and L-galactono-1, 4-lactone dehydrogenase (GalLDH), for AsA synthesis pathways in naked oat leaves under salt-alkali mixed stress, as well as monodehydroascorbate reductase (MDHAR) in the AsA-GSH cycle, and decreased the activities of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR), but did not affect the activities of ascorbate oxidase (AO) and glutathione reductase (GR). The addition of HA partially or completely relieved those aforementioned effects. Our results indicated that H2S could increase the efficiency of AsA-GSH cycle by promoting the synthesis of AsA and enhancing the activity of MDHAR, and reduce the oxidative damage of saline-alkali stress to naked oats.

Robust and efficient single-pixel image classification with nonlinear optics.

We present a hybrid image classifier by feature-sensitive image upconversion, single pixel photodetection, and deep learning, aiming at fast processing of high-resolution images. It uses partial Fourier transform to extract the images' signature features in both the original and Fourier domains, thereby significantly increasing the classification accuracy and robustness. Tested on the Modified National Institute of Standards and Technology handwritten digit images and verified by simulation, it boosts accuracy from 81.25% (by Fourier-domain processing) to 99.23%, and achieves 83% accuracy for highly contaminated images whose signal-to-noise ratio is only -17dB. Our approach could prove useful for fast lidar data processing, high-resolution image recognition, occluded target identification, and atmosphere monitoring.

Single-pixel pattern recognition with coherent nonlinear optics.

In this Letter, we propose and experimentally demonstrate a nonlinear-optics approach to pattern recognition with single-pixel imaging and a deep neural network. It employs mode-selective image up-conversion to project a raw image onto a set of coherent spatial modes, whereby its signature features are extracted optically in a nonlinear manner. With 40 projection modes, the classification accuracy reaches a high value of 99.49% for the modified national institute of standards and technology handwritten digit images, and up to 95.32%, even when they are mixed with strong noise. Our experiment harnesses rich coherent processes in nonlinear optics for efficient machine learning, with potential applications in online classification of large-size images, fast lidar data analyses, complex pattern recognition, and so on.

[Theranostics of osteosarcoma and lung metastasis with new integrin α vß 3 receptor targeted radiotracers].

Objective: To investigate the value of integrin α vß 3 targeted microPET/CT imaging with 68Ga-NODAGA-RGD 2 as radiotracer for the detection of osteosarcoma and theranostics of osteosarcoma lung metastasis. Methods: The 68Ga-NODAGA-RGD 2 and 177Lu-NODAGA-RGD 2 were prepared via one-step method and their stability and integrin α vß 3 binding specificity were investigated in vitro. Forty-one nude mice were injected with human MG63 osteosarcoma to established the animal model bearing subcutaneous osteosarcoma ( n=21), osteosarcoma in tibia ( n=5), and osteosarcoma pulmonary metastatic ( n=15). The microPET-CT imaging was carried out in 3 animal models at 1 hour after tail vein injection of 68Ga-NODAGA-RGD 2. Biodistribution study of 68Ga-NODAGA-RGD 2 was performed in animal model bearing subcutaneous osteosarcoma at 10, 60, and 120 minutes. The animal model bearing pulmonary metastatic osteosarcoma was injected with 177Lu-NODAGA-RGD 2 at 7 weeks after model establishment to observe the therapeutic effect of pulmonary metastatic osteosarcoma. Histological and immunohistochemistry examinations were also done to confirm the establishment of animal model and integrin ß 3 expression in animal models bearing subcutaneous osteosarcoma and bearing pulmonary metastatic osteosarcoma. Results: 68Ga-NODAGA-RGD 2 and 177Lu-NODAGA-RGD 2 had good stability in vitro with the 50% inhibitory concentration value of (5.0±1.1) and (6.5±0.8) nmol/L, respectively. The radiochemical purity of 68Ga-NODAGA-RGD 2 at 1, 4, and 8 hours was 98.5%±0.3%, 98.3%±0.5%, and 97.9%±0.4%; while the radiochemical purity of 177Lu-NODAGA-RGD 2 at 1, 7, and 14 days was 99.3%±0.7%, 98.7%±1.2%, and 96.0%±2.8%. 68Ga-NODAGA-RGD 2 microPET-CT showed that the accumulation of 68Ga-NODAGA-RGD 2 in animal models bearing subcutaneous osteosarcoma and osteosarcoma in tibia and in lung metastasis as small as 1-2 mm in diameter of animal model bearing pulmonary metastatic osteosarcoma. Biodistribution study of 68Ga-NODAGA-RGD 2 in animal model bearing subcutaneous osteosarcoma revealed rapid clearance from blood with tumor peak uptake of (3.85±0.84) %ID/g at 120 minutes. The distribution of 177Lu-NODAGA-RGD 2 in lung metastasis was similar with 68Ga-NODAGA-RGD 2. The number and size of osteosarcoma metastasis decreased at 2 weeks after 177Lu-NODAGA-RGD 2 administration and integrin targeting specificity was confirmed by pathology examination. Conclusion: 68Ga-NODAGA-RGD 2 was potential for positive imaging and early detection of osteosarcoma and metastasis. Targeted radiotherapy with 177Lu-NODAGA-RGD 2 was one potential alternative for osteosarcoma lung metastasis.

[Correction Method of Atmospheric Scattering Effect Based on Three Spectrum Bands].

As a major error of CO2 retrieval, atmospheric scattering effect hampers the application of satellite products. Effect of aerosol and combined effect of aerosol and ground surface are important source of atmospheric scattering, so it needs comprehensive consideration of scattering effect from aerosol and ground surface. Based on the continuum, strong and weak absorption part of three spectrum bands O2-A, CO2 1.6 µm and 2.06 µm, information of aerosol and albedo was analyzed, and improved full physics retrieval method was proposed, which can retrieve aerosol and albedo simultaneously to correct the scattering effect. Simulation study on CO2 error caused by aerosol and ground surface albedo CO2 error by correction method was carried out. CO2 error caused by aerosol optical depth and ground surface albedo can reach up to 8%, and CO2 error caused by different types of aerosol can reach up to 10%, while these two types of error can be controlled within 1% and 2% separately by this correction method, which shows that the method can correct the scattering effect effectively. Through evaluation of the results, the potential of this method for high precision satellite data retrieval is obvious, meanwhile, some problems which need to be noticed in real application were also pointed out.

[Errors Analysis and Correction in Atmospheric Methane Retrieval Based on Greenhouse Gases Observing Satellite Data].

High precision retrieval of atmospheric CH4 is influenced by a variety of factors. The uncertainties of ground properties and atmospheric conditions are important factors, such as surface reflectance, temperature profile, humidity profile and pressure profile. Surface reflectance is affected by many factors so that it is difficult to get the precise value. The uncertainty of surface reflectance will cause large error to retrieval result. The uncertainties of temperature profile, humidity profile and pressure profile are also important sources of retrieval error and they will cause unavoidable systematic error. This error is hard to eliminate only using CH4 band. In this paper, ratio spectrometry method and CO2 band correction method are proposed to reduce the error caused by these factors. Ratio spectrometry method can decrease the effect of surface reflectance in CH4 retrieval by converting absolute radiance spectrometry into ratio spectrometry. CO2 band correction method converts column amounts of CH4 into column averaged mixing ratio by using CO2 1.61 µm band and it can correct the systematic error caused by temperature profile, humidity profile and pressure profile. The combination of these two correction methods will decrease the effect caused by surface reflectance, temperature profile, humidity profile and pressure profile at the same time and reduce the retrieval error. GOSAT data were used to retrieve atmospheric CH4 to test and validate the two correction methods. The results showed that CH4 column averaged mixing ratio retrieved after correction was close to GOSAT Level2 product and the retrieval precision was up to -0.24%. The studies suggest that the error of CH4 retrieval caused by the uncertainties of ground properties and atmospheric conditions can be significantly reduced and the retrieval precision can be highly improved by using ratio spectrometry method and CO2 hand correction method.

Decreased P-glycoprotein is associated with the inhibitory effects of static magnetic fields and cisplatin on K562 cells.

In this study, we explored the mechanism of the killing effects of a moderate-intensity static magnetic field (SMF) and cisplatin (DDP) on K562 cells. We analyzed the metabolic activity of cells, the extracellular DDP content, and P-glycoprotein (P-gp) expression after K562 cells were exposed continuously to a uniform 8.8 mT SMF for 8 h, with or without DDP. We found that SMF combined with DDP (10 µg/ml) significantly inhibited the metabolic activity of K562 cells (P < 0.05), while neither DDP nor SMF alone affected the metabolic activity of these cells. In the SMF + DDP group, extracellular DDP content was significantly reduced (P < 0.05). DDP also induced the expression of P-gp (P < 0.05). By contrast, in the SMF + DDP group, P-gp expression decreased compared with the DDP group (P < 0.05). Taken together, our results showed that 8.8 mT SMF enhanced the killing potency of DDP on K562 cells by decreasing the expression of P-gp.

Biologic effects of SMF and paclitaxel on K562 human leukemia cells.

In this study, we evaluated the ability of 8.8 mT static magnetic fields (SMF) to enhance the in vitro action of a chemotherapeutic agent, paclitaxel, against K562 human leukemia cells. We analyzed the cell proliferation, cell cycle distribution, DNA damage and alteration of cell surface and cell organelle ultrastructure after K562 cells were exposed to paclitaxel in the presence or absence of 8.8 mT SMF. The results showed that in the presence of SMF, the efficient concentration of paclitaxel on K562 cells was decreased from 50 to 10 ng/ml. Cell cycle analysis indicated that K562 cells treated with SMF plus paclitaxel were arrested at the G2 phase, which was mainly induced by paclitaxel. Through comet assay, we found that the cell cycle arrest effect of paclitaxel with or without SMF on K562 cells was correlated with DNA damage. The results of atomic force microscopy and transmission electron microscopy observation showed that the cell ultrastructure was altered in the group treated with the combination of SMF and paclitaxel, holes and protuberances were observed, and vacuoles in cytoplasm were augmented. Our data indicated that the potency of the combination of SMF and paclitaxel was greater than that of SMF or paclitaxel alone on K562 cells, and these effects were correlated with DNA damage induced by SMF and paclitaxel. Therefore, the alteration of cell membrane permeability may be one important mechanism underlying the effects of SMF and paclitaxel on K562 cells.