Computed Tomography Radiomics-based Prediction Model for Gender-Age-Physiology Staging of Connective Tissue Disease-associated Interstitial Lung Disease.

PURPOSE: To analyze the feasibility of predicting gender-age-physiology (GAP) staging in patients with connective tissue disease-associated interstitial lung disease (CTD-ILD) by radiomics based on computed tomography (CT) of the chest. MATERIALS AND METHODS: Chest CT images of 184 patients with CTD-ILD were retrospectively analyzed. GAP staging was performed on the basis of gender, age, and pulmonary function test results. GAP I, II, and III have 137, 36, and 11 cases, respectively. The cases in GAP Ⅱ and Ⅲ were then combined into one group, and the two groups of patients were randomly divided into the training and testing groups with a 7:3 ratio. The radiomics features were extracted using AK software. Multivariate logistic regression analysis was then conducted to establish a radiomics model. A nomogram model was established on the basis of Rad-score and clinical factors (age and gender). RESULTS: For the radiomics model, four significant radiomics features were selected to construct the model and showed excellent ability to differentiate GAP I from GAP Ⅱ and Ⅲ in both the training group (the area under the curve [AUC] = 0.803, 95% confidence interval [CI]: 0.724-0.874) and testing group (AUC = 0.801, 95% CI:0.663-0.912). The nomogram model that combined clinical factors and radiomics features improved higher accuracy of both training (88.4% vs. 82.1%) and testing (83.3% vs. 79.2%). CONCLUSION: The disease severity assessment of patients with CTD-ILD can be evaluated by applying the radiomics method based on CT images. The nomogram model demonstrates better performance for predicting the GAP staging.

Radiomics based on preoperative rectal cancer MRI to predict the metachronous liver metastasis.

PURPOSE: At present, there are few effective method to predict metachronous liver metastasis (MLM) from rectal cancer. We aim to investigate the efficacy of radiomics based on multiparametric MRI of first diagnosed rectal cancer in predicting MLM from rectal cancer. METHODS: From 301 consecutive histopathologically confirmed rectal cancer patients, 130 patients who have no distant metastasis detected at the time of diagnosis were enrolled and divided into MLM group (n = 49) and non-MLM group (n = 81) according to whether liver metastasis be detected later than 6 month after the first diagnosis of rectal cancer within 3 years' follow-up. The 130 patients were divided into a training set (n = 91) and a testing set (n = 39) at a ratio of 7:3 by stratified sampling using SPSS 24.0 software. The DWI model, HD T2WI model, and DWI + HD T2WI model were constructed respectively. The best performing model was selected and combined with the screened clinical features (including non-radiomics MRI features) to construct a fusion model. The testing set was used to evaluate the performance of the models, and the area under the curve (AUC) of receiver operating characteristics (ROC) was calculated for both the training set and the testing set. RESULTS: The AUC of the DWI + HD T2WI model in the testing set was higher than that of the DWI or the HD T2 model alone with statistically significance (P < 0.05). The screened clinical features were extramural vascular invasion (EMVI), T and N stages in MRI (mrT, mrN), and the distance from the lower edge of the tumor to the anal verge. The AUC of the fusion model in the testing set was 0.911. Decision curves and nomogram also showed that the fusion model had excellent clinical performance. CONCLUSION: The fusion model of primary rectal cancer MRI based radiomics combing clinical features can effectively predict MLM from rectal cancer, which may assist clinicians in formulating individualized monitoring and treatment plans.

MRI radiomics predicts progression-free survival in prostate cancer.

Objective: To assess the predictive value of magnetic resonance imaging (MRI) radiomics for progression-free survival (PFS) in patients with prostate cancer (PCa). Methods: 191 patients with prostate cancer confirmed by puncture biopsy or surgical pathology were included in this retrospective study, including 133 in the training group and 58 in the validation group. All patients underwent T2WI and DWI serial scans. Three radiomics models were constructed using univariate logistic regression and Gradient Boosting Decision Tree(GBDT) for feature screening, followed by Cox risk regression to construct a mixed model combining radiomics features and clinicopathological risk factors and to draw a nomogram. The performance of the models was evaluated by receiver operating characteristic curve (ROC), calibration curve and decision curve analysis. The Kaplan-Meier method was applied for survival analysis. Results: Compared with the radiomics model, the hybrid model consisting of a combination of radiomics features and clinical data performed the best in predicting PFS in PCa patients, with AUCs of 0.926 and 0.917 in the training and validation groups, respectively. Decision curve analysis showed that the radiomics nomogram had good clinical application and the calibration curve proved to have good stability. Survival curves showed that PFS was shorter in the high-risk group than in the low-risk group. Conclusion: The hybrid model constructed from radiomics and clinical data showed excellent performance in predicting PFS in prostate cancer patients. The nomogram provides a non-invasive diagnostic tool for risk stratification of clinical patients.

Derivatization-free determination of carbonyl compounds using bifunctional chemiluminescence coreactant thiourea dioxide.

Uniquely, thiourea dioxide not only can reduce carbonyl compounds but also generate an oxidant to trigger luminol chemiluminescence. Herein, derivatization-free carbonyl compound detection using bifunctional chemiluminescence coreactant thiourea dioxide has been developed for the first time with the second most crucial flavor benzaldehyde as a representative.

Development of lucigenin-N-hydroxyphthalimide chemiluminescence system and its application to sensitive detection of Co2.

N-hydroxyphthalimide (NHPI) is an efficient organic catalyst and an important chemical raw material which can be used as an intermediate in organic synthesis of drugs and pesticides. In this study, NHPI has been used as a coreactant of lucigenin chemiluminescence (CL) for the first time. The CL of the developed system is significantly enhanced in the presence of Co2+. Therefore, we developed a novel lucigenin-NHPI CL method coupled with flow injection analysis for the sensitive, precise, and selective determination of Co2+. The linear range of this method is 1-1000 nM, and the detection limit is 67 pM (S/N = 3). In addition, this method has a good selectivity for Co2+. It has been applied to the detection of Co2+ in lake water, and the standard recovery rate is 95.9-103.2%, indicating that the method is feasible.

Protective Effects of Grape Seed Proanthocyanidin Extract in Preventing DSS Induced Ulcerative Colitis Based on Pharmacodynamic, Pharmacokinetic and Tissue Distribution.

BACKGROUND: Based on pharmacodynamic, pharmacokinetic and tissue distribution studies, we explored the potential effect of grape seed proanthocyanidin extract (GSPE) on dextran sodium sulfate (DSS) -induced ulcerative colitis in mice and its underlying mechanism. METHODS: A liquid chromatography-mass spectrometry method was developed to measure the content of five components of GSPE in rat plasma and tissue. After oral administration of GSPE, correlative index levels of interleukin- 1ß (IL-1ß), interleukin-6 (IL-6), factor-α (TNF-α), Nitric Oxide (NO), malonaldehyde (MDA), and superoxide dismutase (SOD) were detected in the serum and colon tissues. The protein expression levels of HO-1, Nrf2 and NF-κB in the mouse colonic mucosa were analysed using immunohistochemistry. RESULTS: Pharmacodynamic tests showed substantially reduced mice body weight, diarrhea, and bloody stool in the model group. The pathological damage to the colonic mucosa of mice in the GSPE groups was remarkably reduced in a dose-dependent manner. The histopathological score of the colon in the model group was significantly higher than that of the control group (P <0.05), suggesting that DSS caused severe damage to the colon. After oral administration of GSPE, the serum and colonic tissue levels of IL-1ß, IL-6, TNF-α, NO, and MDA decreased, whereas SOD content increased. Moreover, the protein levels of NF-κB and Keap-1 were significantly decreased, whereas the expression levels of Nrf2 and HO-1 proteins increased (P<0.01) based on the results of the microwaveimmunohistochemical assay. The pharmacokinetic results showed that catechin, epicatechin, and procyanidins B1, B2, and B4 are widely distributed in the tissues and blood of rats and may accumulate in some tissues. Catechin and epicatechin peaked at 0.25 and 1.5 h for the first and second time, respectively. Procyanidin B1, B2, and B4 peaked at 0.5 and 1.5 h for the first and second time, respectively, owing to the effect of the hepato-enteric circulation. The active components of GSPE can reach the colon of the lesion site, and hepatoenteric circulation can increase the residence time of the active components in the body, further increasing the anti-ulcer activity. CONCLUSION: Our findings suggest that GSPE has a potential protective effect against DSS-induced ulcerative colitis in mice.

Development and Validation of a Sensitive UPLC-Q-TOF-MS/MS for the Measurement of Nine Components in Rat Plasma and Tissues and its Application to Pharmacokinetics and Tissue Distribution Studies with Xuanfei Baidu Granules.

BACKGROUND: Xuanfei Baidu granules (XFBD granules) are based on the prescription of Xuanfei Baidu, which showed promise as a first-line treatment against Corona Virus Disease 2019 (COVID-19) in Wuhan, Hubei. On March 2, 2021, XFBD granules were marketed as a novel drug for epidemic diseases. However, there is little information about the pharmacokinetics and tissue distribution of the main constituents in XFBD granules. METHODS: A sensitive analytical method was developed for detecting the marker components of XFBD granules by ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOFMS/ MS), and for studying its pharmacokinetics and tissue distribution by UPLC-QDa. RESULTS: Following an oral administration of a single granule in experimental rats at a dose of 14 g/kg for pharmacokinetic and tissue distribution studies, 42 compounds and nine analytes were identified in XFBD granules. Nine compounds were detected in the lungs and the liver of the rats. Six compounds were detected in the kidneys. Five compounds were detected in the spleen and three were detected in the heart. As it went undetected in the brain, XFBD granules are considered unable to cross the blood-brain barrier. CONCLUSION: A sensitive UPLC-Q-TOF-MS/MS method was established and validated for the quantification of nine components in rat plasma and tissue samples. This method was successfully applied to study the pharmacokinetics and tissue distribution profiles of XFBD granules after their oral administration.

Effectiveness of the fruit of Rosa odorata sweet var. gigantea (Coll. et Hemsl.) Rehd. et Wils in the protection and the healing of ethanol-induced rat gastric mucosa ulcer based on Nrf2/NF-κB pathway regulation.

ETHNOPHARMACOLOGICAL RELEVANCE: Rosa odorata Sweet var. gigantea (Coll. et Hemsl.) Rehd. et Wils (Rosaceae), is also known as "GU-GONG-GUO", the root of which has been recognized as common ethnodrug from the Yi nationality for treating inflammatory bowel disease. The aim of the present study was to investigate the preventive and curative effects of extract from the fruits of Rosa odorata Sweet var. gigantea (Coll.et Hemsl.) Rehd. et Wils (FOE) in vitro and in vivo as well as elucidate the potential mechanisms of the action involved. MATERIALS AND METHODS: Male Wistar rats were applied to ethanol-induced gastric ulcer model. They were divided into six groups: control, model (GU), positive (Magnesium aluminate chewable tablets, 125 mg/kg), FOE low (125 mg/kg), middle (250 mg/kg) and high (500 mg/kg) doses groups. Histopathology observation of gastric tissues was detected by hematoxylin and eosin (H&E) staining. The expression of Nrf2, HO-1, Keap1, NF-κB p65 and IKKα/ß in gastric tissues were evaluated by immunohistochemistry (IHC). The levels of cytokines in serum and tissues were measured by Enzyme-linked immunosorbent assay (ELISA). The expression of Nrf2, HO-1, Keap1, NF-κB p65, IKKα/ß, PCNA and COX2 proteins were ulteriorly assessed by Western blotting to elucidate the molecular mechanism of FOE's protective effect on gastric ulcer. RESULTS: MTT detection showed that LPS reduced RAW264.7 cell survival, and FOE blocked the inhibition of RAW264.7 cell growth induced by LPS. When RAW264.7 cells were treated with both FOE (100 µg mL-1) and LPS (5 µg mL-1) for 24 h, compared with the model group, the level of NO, TNF-α, IL-6, IL-1ß and MDA significantly decreased, and the activity of SOD was significantly reduced. Obvious pathological injuries in the GU model group were observed, which was improved after treatments with FOE. The contents of pro-inflammatory factors in serum and tissues were decreased by 25% whereas prostaglandin E2 (PGE2) and epidermal growth factor (EGF) were increased by 30% in a dose-dependent manner after FOE (500 mg/kg) treatments. In addition to the promotion effects of superoxide dismutase (SOD), FOE (500 mg/kg) also attenuated the levels of nitric oxide (NO) and malondialdehyde (MDA) by 20%. Likewise, the expression of NF-κB p65, IKKα/ß and Keap1 were suppressed after treatments with FOE whereas Nrf2 and HO-1 showed the opposite trend, which mechanisms were found to be associated with Nrf2/NF-κB signaling pathways. CONCLUSION: The study demonstrated that FOE is able to protect against GU via inhibiting NF-κB signaling pathway and activating Nrf2 signaling pathway, which might provide a stronger theoretical basis for the treatment of GU.

SOX4 induces drug resistance of colorectal cancer cells by downregulating CYLD through transcriptional activation of microRNA-17.

Exposure to high doses of anticancer drugs can induce the emergence of a subpopulation of weakly proliferative and drug-tolerant cells. Drug tolerance can reduce the benefits obtained from canonical treatment and reduce the survival rate of patients. Regulation of SRY-related HMG box transcription factor 4 (SOX4) has been proved to affect drug sensitivity. The current study aimed to explore the role of SOX4 in drug resistance of colorectal cancer (CRC) cells as well as the related molecular mechanisms. Expression patterns of SOX4, microRNA-17 (miR-17), and CYLD in both CRC tissues and cells were determined with their relationship analyzed by bioinformatics analysis, dual-luciferase reporter gene assay, and ChIP. Loss- and gain-function assays were performed to ascertain the effect of SOX4, miR-17, and CYLD on biological cellular processes and drug resistance to 5-FU. SOX4 and miR-17 were found to be highly expressed while CYLD was poorly expressed in CRC tissues and cells. Silencing of SOX4 resulted in the suppression of cellular proliferation, invasion, migration as well as a reduction in CRC drug resistance. Mechanically, CYLD was specifically targeted by miR-17, while SOX4 upregulated the expression of miR-17. Functionally, SOX4 triggered drug resistance of CRC cells to 5-FU through the miR-17/CYLD axis. Taken together, the key findings of the present study provides evidence suggesting that SOX4 elevates miR-17 to decrease CYLD, thus inducing chemotherapy resistance of CRC cells.

Corrigendum: MRI radiomics predicts progression-free survival in prostate cancer.

[This corrects the article DOI: 10.3389/fonc.2022.974257.].

A novel dual response ratiometric fluorescent probe for the determination of H2O2 and glucose via etching of silver nanoparticles.

Based on the inner filter effect and charge transfer dual response mechanism, a dual response ratiometric fluorescent probe (D-RFP) with two reversible signal changes for sensing H2O2 and glucose was developed. The D-RFP was proposed by embedding glycine-derived carbon dots (CDs) (λem = 400 nm) into silica nanoparticles and covalently linking CdTe quantum dots (QDs) (λem = 600 nm) onto the surface of silica nanoparticles. When silver nanoparticles (Ag NPs) were mixed with D-RFP, the fluorescence intensity of CDs can be quenched by Ag NPs via the inner filter effect. With the addition of H2O2, Ag NPs were etched to silver ions, thus recovering the fluorescence of CDs. In the meantime, fluorescence of QDs was quenched by Ag+via charge transfer. Under optimal conditions, D-RFP displayed high sensitivity toward H2O2 with a detection limit of 0.28 µM. Based on the conversion of glucose into H2O2, D-RFP can also be exploited for glucose sensing with a detection limit of 0.59 µM. The approach developed can be applied to monitor glucose levels in human serum samples with satisfactory results, and the results of the heathy and diabetic patients can be distinguished by the naked eye. Moreover, this method provides a new idea for designing a high-sensitivity D-RFP.

Effect of surface charge status of amorphous porous coordination polymer particles on the adsorption of organic dyes from an aqueous solution.

The surface charge status of coordination polymer particles (CPPs) from negative electrification through electrically neutral to positive electrification was achieved by varying the amount of acetic acid. The adsorption capacity of CPPs-1 with a negatively charged framework for the anionic dye Congo red (CR) is much higher than that of the CPPs-5, which possess a positively charged framework, because of different adsorption mechanisms. This is the first reported example of negatively charged CPPs exhibiting excellent adsorption performance toward anionic organic dyes. Broadly, the obtained results shed light on the mechanism of organic dye adsorption on CPPs. The CPP nanostructures exhibit excellent adsorption capabilities for the CR dye, with a maximum capacity of 1033.2 mg g-1, which is higher than that of most reported materials. The influences of variables such as initial pH, organic dye concentration, and contact time were investigated. The results indicate that the CPPs-1 nanostructures have promising application in CR dye-containing wastewater treatment.

Highly Sensitive Ratiometric Fluorescent Sensor for Trinitrotoluene Based on the Inner Filter Effect between Gold Nanoparticles and Fluorescent Nanoparticles.

In this work, we developed a simple and sensitive ratiometric fluorescent assay for sensing trinitrotoluene (TNT) based on the inner filter effect (IFE) between gold nanoparticles (AuNPs) and ratiometric fluorescent nanoparticles (RFNs), which was designed by hybridizing green emissive carbon dots (CDs) and red emissive quantum dots (QDs) into a silica sphere as a fluorophore pair. AuNPs in their dispersion state can be a powerful absorber to quench CDs, while the aggregated AuNPs can quench QDs in the IFE-based fluorescent assays as a result of complementary overlap between the absorption spectrum of AuNPs and emission spectrum of RFNs. As a result of the fact that TNT can induce the aggregation of AuNPs, with the addition of TNT, the fluorescent of QDs can be quenched, while the fluorescent of CDs would be recovered. Then, ratiometric fluorescent detection of TNT is feasible. The present IFE-based ratiometric fluorescent sensor can detect TNT ranging from 0.1 to 270 nM, with a detection limit of 0.029 nM. In addition, the developed method was successfully applied to investigate TNT in water and soil samples with satisfactory recoveries ranging from 95 to 103%, with precision below 4.5%. The simple sensing approach proposed here could improve the sensitivity of colorimetric analysis by changing the ultraviolet analysis to ratiometric fluorescent analysis and promote the development of a dual-mode detection system.

PEG-imbedded PEO membrane developed by a novel highly efficient strategy toward superior gas transport performance.

Low-molecular-weight poly(ethylene glycol) (PEG) is deliberately incorporated into synthesized swellable poly(ethylene oxide) (PEO) membranes via a facile post-treatment strategy. The membranes exhibit both larger fractional free volume (FFV) and a higher content of CO2-philic building units, resulting in significant increments in both CO2 permeability and CO2/H2 selectivity. The separation performance correlates nicely with the microstructure of the membranes. This study may provide useful insights in the formation and mass transport behavior of highly efficient polymeric membranes applicable to clean energy purification and CO2 capture, and possibly bridge the material-induced technology gap between academia and industry.

[Microclimate dynamics of pit and mound complex within different sizes of forest gaps in Pinus koraiensis-dominated broadleaved mixed forest].

An investigation was conducted in a 2.25 hm2 plot of Pinus koraiensis-dominated broad-leaved mixed forest to study basic characteristics of 7 small gaps, 5 middle gaps, 3 large gaps and 7 closed stands within 38 pit and mound complexes caused by treefall in May 2012. From June to September 2012, the soil temperature, soil water content and relative humidity at five microsites (pit bottom, pit wall, mound top, mound face and undisturbed closed stands) were measured in six sunny days each month. The results showed that among the five microsites in every month, the mound top had the highest soil temperature and the lowest water content and relative humidity, and vice versa for the pit bottom. Mostly, the differences in the above indicators among the five microsites were significant. From June to September, the mean soil temperatures for all microsites at pit and mound complex in the various gaps and closed stands were in the order of large gap>middle gap >small gap>closed stand; but the soil water content ranked differently every month. In June, August and September, the mean relative humidities for all microsites in the various gaps and closed stands were in the order of closed stand>small gap>middle gap>large gap. Mostly, the differences in the above indicators between all microsites in the various gaps and closed stand were significant. The mean monthly soil temperature and relative humidity were highest in July, but lowest in September. The maximal mean monthly soil water content occurred in July and the minimal one in September for each microsite except the undisturbed closed stands, where the maximal mean monthly soil water content occurred in July. The variation of the microclimate at the pit and mound complex was mainly influenced by gap size, microsite, and time.

[Dimensional characteristics and spatial distribution patterns of pit and mound complexes in Pinus koraiensis-dominated broadleaved mixed forest].

Characteristics of pit and mound complexes in different sizes of forest gaps and closed stands and their distribution patterns were compared and analyzed. The results showed that mean mound width, mound height, mound thickness of all pit and mound complexes were larger than corresponding mean pit length, pit width, pit depth in large, medium and small gaps as well as in closed stands. Mound width, mound height, mound thickness, pit length, pit width, pit depth were the largest in large gap, being 2.85, 0.37, 2.00, 2.99, 2.10, 0.39 m, respectively, and the smallest in closed stands, being 2.35, 0.19, 1.60, 2.66, 1.65, 0.21, respectively. Mean mound volume (1.66 m3) was larger than mean pit volume (1.44 m3). The difference in characteristic values between the most of pit and mound complexes was significant for the same size of forest gap, not significant for closed stands, significant for different sizes of forest gaps and closed stands. Most of characteristic values for pit and mound complexes within the plot in 2012 were significantly less than those in 2011. 89.5% and 60.5% of type and shape of pit and mound complexes were hinge and semiellipse, respectively. Their distribution was relatively centralized.

[Effects of forest gap size and light intensity on herbaceous plants in Pinus koraiensis-dominated broadleaved mixed forest].

1 m x 1 m fixed quadrats were parallelly arranged with a space of 2 m in each of six forest gaps in Pinus koraiensis-dominated broadleaved mixed forest, taking the gap center as the starting point and along east-west and south-north directions. In each quadrat, the coverage and abundance of herbaceous plants at different height levels were investigated by estimation method in June and September 2011, and the matrix characteristics within the quadrats were recorded. Canopy analyzer was used to take fish-eye photos in the selected overcast days in each month from June to September, 2011, and the relative light intensity was calculated by using Gap Light Analyzer 2.0 software. The differences in the relative light intensity and herbaceous plants coverage and richness between different gaps as well as the correlations between the coverage of each species and the direct light, diffuse light, and matrix were analyzed. The results showed that in opening areas and under canopy, the relative light intensity in large gaps was higher than that in small gaps, and the variation ranges of diffuse light and direct light from gap center to gap edge were bigger in large gaps than in small gaps. The direct light reaching at the ground both in large gaps and in small gaps was higher in the north than in the south direction. In the Z1, Z2, Z3, and Z4 zones, both the coverage and the richness of herbaceous plants were larger in large gaps than in small gaps, and the differences of species richness between large and small gaps reached significant level. The coverage of the majority of the herbaceous plants had significant correlations with diffuse light and matrix, and only the coverage of a few herbaceous plants was correlated with direct light.

[Microsite characteristics of pit and mound and their effects on the vegetation regeneration in Pinus koraiensis-dominated broadleaved mixed forest].

Abstract: An investigation was conducted in a 2.55 hm2 plot of Pinus koraiensis-dominated broad-leaved mixed forest to study the microsite characteristics of pit and mound formed by 42 treefalls and the status of vegetation regeneration on the microsites. The soil water content, soil temperature, relative air humidity, and photosynthetically active radiation (PAR) on five microsites (mound top, mound face, pit wall, pit bottom, and intact forest floor) were measured. Among the five mirosites, mound top had the highest PAR (527.9 micromol.m-2.s-1 ) while intact forest floor had the lowest one (58.7 micromol.m-2.s-), mound top had the highest soil temperature (16.0 degrees C) but pit bottom had the lowest one (13.3 degrees C), pit bottom had the highest soil water content (34.6%) but mound face had the lowest one (0.5%), and intact forest floor had the highest relative air humidity (75.9%) but mound top had the lowest one (68.0%). The frequency of forming pit/ mound complex by the tree species was decreased in the order of Pinus koraiensis (42. 9%) >Picea asperata (31.0%) > Betula platyphylla (16.7%) > Abies fabri (7. 1%) > Prunus padus (2.4%). Among the 42 treefalls, two-thirds of them were in northwest direction. The treefalls volume had significant positive correlations with pit depth, pit length, mound height, and mound width, but negative correlation with mound thickness. The treefall mean diameter at breast height had significant positive correlations with pit width (r=0.328, P=0.017) and pit length (r=0.527, P= 0). The tree species richness at the microsites decreased in the order of intact forest floor > pit > mound, and the tree species coverage was in the sequence of intact forest floor > pit > mound.

[Effects of gap size on the spatial heterogeneity of soil water in Pinus koraiensis-dominated broad-leaved mixed forest].

In August-October 2011, the soil water content (SWC) at different depths in different sized gaps in Pinus koraiensis-dominated broad-leaved mixed forest of Xiaoxing' an Mountains, Northeast China was continuously measured by grid nesting method and time domain reflectometry (TDR), and the spatial heterogeneity of the SWC was analyzed by the principles and approaches of geostatistics. The SWC was most abundant in medium gap, followed by in large gap and in small gap whereas the maximum difference of SWC was the biggest in large gap, followed by in medium gap, and in small gap. The variation range of the nugget of SWC at different depths in the large, medium, and small gaps was 0.001-0.404, 0.001-0.273, and 0.001-0.261, respectively. The SWC heterogeneity resulted from random part and the total system SWC spatial heterogeneity were decreased in the order of large gap > medium gap > small gap. The spatial distribution pattern of SWC was most complicated in medium gap, while the spatial dependence in the variation of the SWC pattern was the strongest in large gap. High-grade patches (SWC was 50%-60%) occupied the largest area in medium gap, followed by in large gap, and there was no high-grade patch in small gap. As for the SWC at same depths and in same months, its grade distribution was most simple in small gap, but relatively complicated in large and medium gaps. The maximum value of SWC increased with increasing gap size.

[Effects of forest gap size and uprooted microsite on the microclimate in Pinus koraiensis-dominated broad-leaved mixed forest].

Three representative forest gaps with pit-mound microsites formed by uprooted trees were selected within the 2.55 hm2 plot in a Pinus koraiensis-dominated broad-leaved mixed forest in Xiao Xing'an Mountains of Northeast China. The cleared land and closed stand were set up as the controls, and the PAR, air temperature and relative humidity in the centers of different size gaps and in mound top as well as the total radiation and precipitation in the gap centers were measured between July and September, 2011 by using multichannel automatic meteorological stations. The differences of the microclimate between the gap centers and mound top in different months were compared, and the monthly and diurnal variations of the microclimatic factors in the gap centers and in the mound top under typical weather conditions were analyzed. The results showed that the mean monthly PAR and air temperature in the three gaps of different sizes were in the order of large gap > medium gap > small gap, and the mean monthly relative humidity was in the order of small gap > medium gap > large gap. For the same size gap, the mean monthly PAR and air temperature were higher in the mound top than in the gap center, whereas the mean monthly relative humidity was higher in the gap center than in the mound top. Both the mean monthly total radiation and the mean monthly air temperature in the forest gaps and in the controls were in the order of July > August > September and of cleared land > large gap > medium gap > small gap > closed stand, while the mean monthly relative humidity was in the order of closed stand > small gap > medium gap > large gap > cleared land. The differences in the mean monthly relative humidity between closed stand and various gaps and between closed stand and cleared land reached significant level. The monthly precipitation from July to September decreased in the order of cleared land > large gap > medium gap > small gap > closed stand. Whether in sunny days or in overcast days, the mean daily PAR and air temperature were higher in mound top than in gap center, and the mean daily relative humidity was in opposite. Whether in mound top or in gap center, the mean daily PAR and air temperature were higher in sunny days than in overcast days, while the mean daily relative humidity was higher in overcast days than in sunny days.