Recent advances in starch-based coatings for the postharvest preservation of fruits and vegetables

Efficient and low-cost postharvest preservation of fruits and vegetables has always been one of the urgent problems to be solved in the food field. Due to the wide sources, good environmental and human safety, and high biodegradability, starch-based coating preservation method has great application prospects in the postharvest preservation of fruits and vegetables. However, starch materials also have the disadvantages of poor mechanical properties and easy water absorption performance, which makes it difficult to fully meet the requirements in practical production. Therefore, starch is often used in combination with other components to form composite materials. This paper began with an introduction to the preservation principles of edible starch-based coatings, including inherent properties and extra functional properties. Besides, the preservation principles of edible coatings and the recent advances in the field of fruit and vegetable preservation were also comprehensively reviewed, focusing on the preparation and application of starch-based coatings. The information will contribute to the further development of starch-based coatings to improve the postharvest preservation effect of fruits and vegetables.

Recent preparation, modification and application progress of starch nanocrystals: A review

Due to the advantages of wide sources, high biocompatibility and favorable biodegradability, starch nanocrystals (SNCs) have gradually attracted attention and have bright development prospects in food, agriculture, materials, medicine and other fields. However, the traditional preparation method of SNCs is time-consuming and inefficient, and the physicochemical properties cannot fully meet the needs of multiple applications. Fortunately, the unique onion-like structure of starch granules and the large number of hydroxyl groups present on the surface entitle SNCs to efficient preparation and modification. This paper comprehensively reviewed the improvement methods of SNCs preparation process in recent years, and the advantages and disadvantages of the two improvement strategies were compared. Besides, the importance of introducing different pretreatment methods into the SNCs preparation process was emphasized. It also focused on the different modification treatment and application progress of SNCs, especially in the starch-based surface coating of fruits and vegetables. The information will contribute to further improve the preparation efficiency and physicochemical properties of SNCs, and ultimately expand the application field.

Characterization of Colletotrichum Causing Anthracnose on Rubber Trees in Yunnan: Two New Records and Two New Species from China

Among the most damaging diseases of rubber trees is anthracnose caused by the genus Colletotrichum, which leads to significant economic losses. Nonetheless, the specific Colletotrichum spp. that infect rubber trees in Yunnan Province, an important natural rubber base in China, have not been extensively investigated. Here, we isolated 118 Colletotrichum strains from rubber tree leaves exhibiting anthracnose symptoms in multiple plantations in Yunnan. Based on comparisons of their phenotypic characteristics and internal transcribed spacer ribosomal DNA sequences, 80 representative strains were chosen for additional phylogenetic analysis based on eight loci (act, ApMat, cal, CHS-1, GAPDH, GS, his3, and tub2), and nine species were identified. Colletotrichum fructicola, C. siamense, and C. wanningense were found to be the dominant pathogens causing rubber tree anthracnose in Yunnan. C. karstii was common, whereas C. bannaense, C. brevisporum, C. jinpingense, C. mengdingense, and C. plurivorum were rare. Among these nine species, C. brevisporum and C. plurivorum are reported for the first time in China, and two species are new to the world: C. mengdingense sp. nov. in the C. acutatum species complex and C. jinpingense sp. nov. in the C. gloeosporioides species complex. Their pathogenicity was confirmed with Koch's postulates by inoculating each species in vivo on rubber tree leaves. This study clarifies the geographic distribution of Colletotrichum spp. associated with anthracnose on rubber trees in representative locations of Yunnan, which is crucial for the implementation of quarantine measures.

The Effects of Shrub Removal on Soil Microbial Communities in Primary Forest, Secondary Forest and Plantation Forest on Changbai Mountain

Shrub removal is a common management method in forest ecosystems, but comparatively little is known regarding the effects of shrub removal on soil microbial communities among primary forest, secondary forest, and plantation forests in temperate forests, which limits our accurate assessment of sustainable management of understory vegetation removal. Given this, we used a long-term operation experiment across a contrasting mixed broadleaved-Pinus koraiensis forest, Betula platyphylla forest, and Larix gmelinii plantation forest to explore the variations of soil properties and microbial community after 5 years of shrub removal on Changbai Mountain, as well as the contribution of the soil properties and understory plant diversity to the soil microbial community. The results demonstrated that shrub removal could significantly alter soil SWC and TN, TP, and AP contents of the L. gmelinii, as well as N/P of B. platyphylla. Moreover, shrub removal also clearly improved soil bacterial Pielou_e index and Simpson index of mixed broadleaved-P. koraiensis and soil bacterial Simpson index of L. gmelinii, and decreased soil fungal Pielou_e index and Shannon index of L. gmelinii and soil bacterial Pielou_e index and soil fungal Shannon index of B. platyphylla. Identically, shrub removal notably altered the soil bacterial community composition. Soil characteristics and understory plant diversity accounted for 48.02% and 26.88%, and 45.88% and 27.57% of the variance in the bacterial and fungal community composition, respectively. This study aimed to provide an important scientific basis for the restoration and sustainable management of temperate forests in the Changbai Mountain region.

A framework of freshwater services flow model into assessment on water security and quantification of transboundary flow: A case study in northeast China

Ecosystem service flow dynamics which establish the linkage between human and nature is essential in an ecosystem service assessment. This study constructed an ecosystem service flow model of freshwater flow then utilized it to assess the water-related ecosystem services in northeast China. We included the provision, consumption, and spatial flow of freshwater services in an index to assess the water security condition and quantified the services trans-boundary flow from the northeast forest belt (NFB) in northeast China. Our results showed that large areas (50.54%, 55.10% and 52.90%, respectively) of northeast China received upstream freshwater service in three years. The water security condition of northeast China deteriorated from 2005 to 2015 with the change of water security index considering water flow (WSI_flow), mainly influenced by precipitation and agriculture water consumption. Approximately 4.16 billion m³ of freshwater service were delivered from NFB to surrounding regions demonstrating the importance of NFB in terms of ecosystem service provision. In addition, 73 key watersheds (4.71% of total area) within NFB that significantly affect the trans-boundary flow were further identified. We suggested that local government should advocate develop water-saving agriculture and livestock water quotas. Moreover, priorities should be given to protect the key watersheds within NFB in order to maintain the supply of freshwater service. This study provided a framework for exploring suitable strategies for managing water resources and laid a foundation for promoting the ecological compensation in the future.

In silico nanosafety assessment tools and their ecosystem-level integration prospect

Engineered nanomaterials (ENMs) have tremendous potential in many fields, but their applications and commercialization are difficult to widely implement due to their safety concerns. Recently, in silico nanosafety assessment has become an important and necessary tool to realize the safer-by-design strategy of ENMs and at the same time to reduce animal tests and exposure experiments. Here, in silico nanosafety assessment tools are classified into three categories according to their methodologies and objectives, including (i) data-driven prediction for acute toxicity, (ii) fate modeling for environmental pollution, and (iii) nano-biological interaction modeling for long-term biological effects. Released ENMs may cross environmental boundaries and undergo a variety of transformations in biological and environmental media. Therefore, the potential impacts of ENMs must be assessed from a multimedia perspective and with integrated approaches considering environmental and biological effects. Ecosystems with biodiversity and an abiotic environment may be used as an excellent integration platform to assess the community- and ecosystem-level nanosafety. In this review, the advances and challenges of in silico nanosafety assessment tools are carefully discussed. Furthermore, their integration at the ecosystem level may provide more comprehensive and reliable nanosafety assessment by establishing a site-specific interactive system among ENMs, abiotic environment, and biological communities.

Preparation and characterization of cross-linked starch nanocrystals and self-reinforced starch-based nanocomposite films

In this study, starch-based nanocomposite films reinforced by cross-linked starch nanocrystals (CSNCs) were successfully prepared. CSNCs were obtained by cross-linking reaction between starch nanocrystals (SNCs) and sodium hexametaphosphate (SHMP). Through the characterization and comparison of SNCs and CSNCs in microscopic morphology, degree of substitution, swelling degree, XRD spectrum, and FTIR spectrum, the successful progress of the cross-linking reaction was confirmed. Besides, the effects of adding CSNCs on physiochemical properties of the nanocomposite films including mechanical properties, water vapor permeability, and contact angle were studied. The results confirmed that CSNCs had good enhancement effects on the physicochemical properties of starch-based films due to the self-reinforcing effect, and when the CSNCs content reached 10%, the nanocomposite film had the best overall performance. We further evaluated the cytotoxicity of the nanocomposite. Taken together, it is believed that the reported self-reinforced starch-based films are very promising for food packaging and preservation.

Cross-linked starch-based edible coating reinforced by starch nanocrystals and its preservation effect on graded Huangguan pears

Starch-based nanocomposite film/coating made from cross-linked cassava starch reinforced by starch nanocrystals (SNCs) was successfully prepared. The effects of SNCs contents on the color, transparency, roughness, mechanical properties, water vapor permeability, and FTIR spectroscopy of the films were explored. The results showed that the film with 6% SNCs had the best comprehensive performance. Subsequently, graded Huangguan pears were coated with the formulation-optimized coating and stored at 20 °C for 4 weeks. From the physicochemical parameters of pears, it can be found that the grading treatment was detrimental to the preservation of pears, while the coating treatment was significantly effective for extending shelf life. Besides, the pattern of grading before coating was more advantageous for pear preservation. In general, this study firstly applied cross-linked starch-based nanocomposite coating on the preservation of pear, which had practical significance for expanding the use of nanocomposite coating reinforced by SNCs and pear preservation methods.

[Study on the relationship between EPHX1 gene polymorphism and antioxidant capacity in patients with chronic obstructive pulmonary disease]

Objective: To explore the difference of mRNA, protein expression levels and the indexes of peripheral blood antioxidant capacity in peripheral blood lymphocytes of different EPHX1 genotypes in chronic obstructive pulmonary disease(COPD). Methods: A case-control study was conducted to collect peripheral blood samples of 220 stable chronic COPD patients with smoking history and 230 healthy smokers (control group) from October 2016 to February 2018 in the First Affiliated Hospital of Kunming Medical University, and the genetic testing was carried out according to the operation instructions of BigDye Terminator v1.1 DNA Sequencing Kit. Based on their EPHX1 exon 3 and exon 4 polymorphism status, the EPHX1 was classified into 4 groups, i. e., normal activity, slow activity, extremely slow activity and fast activity. Then COPD patients were allocated to either a slow activity group (slow and very slow activity) or a fast activity group (normal and fast activity) according to EPHX1 genotype and gene activity. The expression of EPHX1 mRNA and protein in peripheral blood lymphocytes were detected by qRT-PCR and Western blot, and indexes of serum antioxidant capacity was detected by corresponding kits. Results: (1)The 2(-ΔΔCt) of the control group was 1.000, and the 2(-ΔΔCt) of the COPD group was 1.052±0.023. There was no significant difference in the level of EPHX1 mRNA expression between the two groups (t=1.992 P=0.865). The level of EPHX1 mRNA expression in the slow activity group was not different significantly compared to that in the fast-active group (1.053±0.023 vs 1.048±0.021, t=1.133, P=0.260). (2)The level of EPHX1 protein expression by Western blot analysis showed that the EHPX1/GAPDH gray ratio was not different significantly between the COPD group and the control group (0.613±0.089 vs 0.602±0.075, t=0.805, P=0.422). The level of EPHX1 protein expression in the slow activity group was not significantly different compared to that in the fast activity group (0.606±0.088 vs 0.622±0.092, t=-0.786 P=0.434). (3)There were significant differences in indexes of antioxidant capacity between the control group and the COPD group (P<0.05). There were significant differences in indexes of antioxidant capacity between the slow activity group and the fast activity group of COPD patients (P<0.05). Conclusions: The different antioxidant capacity of COPD patients with different EPHX1 genotypes may be related to the polymorphism of EPHX1 gene affecting the activity of microsomal epoxidase, but not to the level of EPHX1 mRNA and protein expression.

[Comparative analysis of clinical characteristics and prognosis between bacterial necrotizing pneumonia and Mycoplasma pneumoniae necrotizing pneumonia in children]

Objective: To compare the characteristics of Mycoplasma pneumoniae necrotizing pneumonia (MPNP) and bacterial necrotizing pneumonia (BNP), and explore the biomarkers for differentiation of MPNP from BNP. Methods: A retrospective, observational study of 52 necrotizing pneumonia (NP) cases who were hospitalized in our hospital from January 2008 to December 2017 was conducted. According to the pathogen causing NP, patients were divided into two groups, BNP and MPNP, and the clinical manifestations, laboratory data, imaging findings, hospital course and prognosis between these groups were analyzed. Results: This study enrolled 19 boys and 33 girls, and the median ages of patients were 4.4 (0.1-13.8) years old. Of the totally of 52 NP patients, 19 were in the BNP group (9 boys and 10 girls), 33 were in the MPNP group (10 boys and 23 girls). The mean age of MPNP patients was much older than that of BNP patients (5.2 (2.3-13.2) years vs. 1.8 (0.1-13.8) years, Z=-0.128, P<0.01). The number of patients with tachypnea and pleural effusion septation were significantly higher in BNP patients than those in MPNP patients (15 cases vs. 4 cases, χ(2)=23.222, P<0.01; 14 cases vs. 1 case, χ(2)=29.326, P<0.01), which more needed to oxygentherapy (18 cases vs. 12 cases, χ(2)=16.833, P<0.01) and undergo chest drainage (9 cases vs. 4 cases, χ(2)=5.829, P=0.022); while the number of patients required bronchoalveolar lavage was higher in MPNP patients than that in BNP patients (5 cases vs. 32 cases, χ(2)=29.326, P<0.01). The values of white blood cell (WBC) (23.2 (5.2-67.1)×10(9)/L vs. 9.7 (6.3-18.7)×10(9)/L, Z=-4.855, P<0.01), procalcitonin (PCT) (3.69 (0.23-90.15) mg/L vs. 0.28 (0.02-1.44) mg/L, Z=-3.207, P=0.001), C reactive protein (CRP) (160 (94-220) mg/L vs. 90 (5-134) mg/L, Z=-4.337, P<0.01), interleukin (IL)-10 (11.7 (4.2-401.5) ng/L vs. 4.8 (2.0-23.4) ng/L, Z=-2.278, P=0.023), pleural fluid cell count (5 200 (120-50 000)×10(6)/L vs. 790 (68-6 920)×10(6)/L, Z=-3.125, P=0.002), pleural fluid lactic dehydrogenase (LDH) (3 990 (589-29 382) U/L vs. 2 211 (673-3 993) U/L, Z=-2.488, P=0.013) in BNP group were significantly higher than those in MPNP group; while the values of pleural fluid glucose(0.43 (0.03-18.00) mmol/L vs. 5.95 (4.27-7.87) mmol/L, Z=-2.795, P=0.005), serum tumor necrosis factor (TNF)-α (2.3 (1.0-2.8) ng/L vs. 2.6 (1.3-109.2) ng/L, Z=-2.113, P=0.035) and interferon (IFN)-γ (4.8 (2.6-7.7) ng/L vs. 11.9 (2.9-154.6) ng/L, Z=-2.455, P=0.014) were lower in BNP group than those in MPNP group. Meanwhile, the mean time from the onset of symptoms to the discovery of necrotic lesions was longer in MPNP group than that in BNP group ((20.6±6.4) days vs. (14.6±6.2) days, t=3.029, P=0.004). After treatments, all patients were discharged without death, WBC and PCT recovered more quickly in MPNP group than those in BNP group (12 (0-24) days vs. 0 (0-23) days, Z=-4.484, P<0.01; 10 (5-15) days vs. 0 (0-23) days, Z=-3.244, P=0.001). As to prognosis, 34 cases were followed up, and the results showed that patients recovered without surgical intervention, and chest lesions were resolved within 3.0 (1.0-8.0) months, and the time to necrosis disappearance was similar in the BNP group and MPNP greup (3.0 (1.0-8.0) months vs. 3.0 (1.0-8.0) months, Z=-0.128, P=0.001). In receiver operator characteristic curve analysis, the cut-off values for the age, WBC, CRP, PCT, pleural fluid cell count and pleural fluid glucose were set at 2.4 years of age, 17.2×10(9)/L, 157 mg/L, 1.505 mg/L, 2 630×10(6)/L and 3.73 mmol/L, respectively. Conclusions: NP is found to be severe and prolonged, yet, reversible through proper therapy, such as rational antibiotics application. The age, WBC, CRP, PCT, pleural fluid cell count and pleural fluid glucose could be used as biomarkers to differentiate MPNP from BNP in children.

[Seasonal distribution of patient hospitalization due to asthma exacerbation in 7 geographic areas in China]

Objective: To understand the seasonal distribution of patient hospitalization due to asthma exacerbation in 7 geographic areas in China. Methods: This was a retrospective study which involved patients hospitalized for asthma exacerbation in 29 hospitals throughout 7 geographic areas in the mainland of China (northeast, north, central, east, south, northwest and southwest). The numbers of asthmatic patients and total inpatients of the respiratory department of each hospital were recorded. The monthly ratio of asthmatic patients to the total inpatients in every area was calculated and compared. Results: During the study period, 6 480 patients were admitted for asthma exacerbation, accounting for 3.14% of all the 206 135 patients admitted to the respiratory departments in the 29 hospitals. The ratio of asthmatic patients to total inpatients in the northeast area (5.61%) was highest, and the ratio in east area was lowest (1.97%). Statistical analysis showed that the difference among different areas was significant (P<0.000 1). In most areas, both the number and proportion of hospitalized asthmatic patients peaked in spring (February-April) and autumn (September-October). In the northeast area, east area and south area, the peaks in spring were more obvious, while in the north area and southwest area, the peaks in autumn were more obvious. In the northwest area the peaks occurred in winter (December-January) and summer (June-August), respectively. The differences in hospitalization due to asthma among different months were significant in the northeast, north, and southwest areas (P<0.005). Conclusion: The number of patients hospitalized for asthma exacerbation fluctuated with season in different areas in China. In most areas, more asthmatic patients were admitted to hospitals in spring and autumn.

[Seasonal characteristics of patients hospitalized for asthma exacerbation in China]

Objective: To study the seasonal characteristics of patients hospitalized for asthma exacerbation in China. Methods: This was a retrospective study which involved patients hospitalized for asthma exacerbation in 29 hospitals throughout mainland China during 2013-2014. The number of patients hospitalized for asthma exacerbation in each hospital was calculated, as well as the ratio of asthmatic patients to all the hospitalized patients. The analysis by month was conducted. The number and ratio of asthmatic patients in the northern and southern cities were calculated respectively. Results: During the study period, there were 6 480 patients hospitalized for asthma exacerbation, accounting for 3.14% (6 480/206 135) of all the hospitalized patients of the respiratory department in 29 hospitals. The analysis by month showed that the ratio of patients hospitalized for asthma exacerbation was highest in March (3.49%), then declined from April to June, then rose again from July, reaching a second peak at September (3.28%), and then declined again from October to December. The ratio of asthmatic patients in every month was higher in northern cities than in southern cities. Conclusions: The ratio of patients hospitalized for asthma exacerbation in China fluctuates with the changes of seasons, and March and September are the two peak months. Northern cities have a higher ratio of asthmatic patients than southern cities.

[Warning symptoms of asthma attack and asthma self-management: a national asthma control survey from China]

Objective: To investigate warning symptoms of asthma attack and evaluate asthma self-management status of asthma patients in urban China. Methods: A multi-center, cross-sectional, questionnaire-based survey was carried out from 30 general hospitals dispersed in 30 provinces of mainland China (except for Tibet) during Oct 2015 to May 2016. Information of frequency and warning symptoms of asthma attack, the time from warning symptoms to asthma attack, the impact of asthma attack and asthma self-management were collected from asthma patients of outpatient department. Results: Altogether 3 875 asthmatic outpatients were recruited. 78.1% (3 026/3 875) of the patients reported restriction of exercise and daily activities during asthma exacerbation. 82.5% (3 160/3 829) of the patients had warning symptoms before asthma attack, the most common warning symptoms were cough, chest tightness and shortness of breath. The median time from warning symptoms to asthma attack was 2 h, the mean time was 90 h. Only 4.4% (167/3 829) of the patients had definite confidence to control asthma when symptoms deteriorated. 76.7% (2 937/3 828) of the patients used medications to control asthma when asthma symptoms deteriorated. Medication choice: inhaled corticosteroid (ICS) + formoterol 45.8% (1 776/3 875), short-acting beta-agonist (SABA) 23.9% (927/3 875). Conclusions: Most asthma patients have warning symptoms before asthma attack, the most common symptoms are cough, chest tightness and shortness of breath. The proportion of patients conducting effective asthma self-management remains low.

[The level of asthma control in China from a national asthma control survey]

Objective: To assess the overall asthma control level in urban China. Methods: A multi-center, cross-sectional, questionnaire-based survey was carried out in 30 provinces in China (except Tibet). Asthmatic outpatients who met the inclusion criteria were recruited consecutively from 30 sub-centers from October 2015 to May 2016. Data of demographic characteristics, asthma control, asthma management, asthma exacerbations and self-management, and disease perception were collected by face-to-face interviews. Results: Totally 3 875 asthmatic outpatients were recruited. Asthma control level was assessed according to GINA 2015. The prevalence of asthma control was 28.5%(1 099/3 854). Among 10 cities, which were also involved in the asthma control survey in 2008, the level of asthma control improved from 28.7% in 2008 to 39.2%(533/1 361) in 2016. The rate of hospitalizations due to asthma exacerbations was 26.4%(1 017/3 858) and the rate of emergency visits was 22.4%(864/3 858). Among adult patients, 18.4%(568/3 092) of them had been absent from work while 63.6%(63/99) adolescent patients had been absent from school because of asthma attacks in the previous year. Conclusion: Although the level of asthma control in China is still far from ideal at present, the status has been improved in some cities. Poorly controlled asthma resulted in increase of hospitalizations, emergency department visits and work/school absences.

[A multi-center retrospective study of clinical characteristics and hospitalization costs of patients hospitalized for asthma exacerbation in China during 2013-2014]

Objective: To study the characteristics of patients hospitalized for asthma exacerbation in 29 teaching hospitals in China and to evaluate the hospitalization costs of these patients. Methods: This was a retrospective study and involved patients hospitalized for asthma exacerbation in 29 hospitals throughout China during 2013-2014. Information about the demographic features, conditions before the admission, the outcome, the complications, and the costs was collected using the pre-designed case report form. The influencing factors of the hospitalization costs were analyzed. Results: 3 240 asthmatic patients (1 369 males and 1 871 females) were included and data were analyzed. There were 41.5% (1 346/3 240) patients who had a history of previous hospitalization or emergency department visits during the last year. Only 28.0% (907/3 240) patients had used asthma-controlling medications regularly before the admission. Seventy-three(2.3%) patients were admitted to ICU and used mechanical ventilation. Mortality among these patients hospitalized for asthma exacerbation was 0.25% (8/3 240). The median hospitalization costs was 9 045(6 431, 13 035) RMB. The costs of medications, examinations and treatment accounted for 52.1%, 27.6%, and 9.6% respectively. The costs of asthma medications accounted for only 22.7% of the total medication costs, while the costs of antibiotics accounted for 44.0%. The patients who were admitted to ICU, used mechanical ventilation, complicated with pneumonia, or had a history of hospitalization or emergency department visits during the last year due to asthma exacerbations tended to cost more. Conclusion: In this study, we demonstrated that only a minority of the patients had used asthma controllers regularly before the admissions with exacerbations. The in-hospital mortality of asthma patients in this study was much lower than that reported in other countries. The average cost of hospitalization was much higher than the yearly cost of maintenance therapy. Medication was the predominant component of the total hospitalization costs, and the costs of antibiotics made up the major part of the total medication costs.

Classification of Frozen Corn Seeds Using Hyperspectral VIS/NIR Reflectence Imaging

A VIS/NIR hyperspectral imaging system was used to classify three different degrees of freeze-damage in corn seeds. Using image processing methods, the hyperspectral image of the corn seed embryo was obtained first. To find a relatively better method for later imaging visualization, four different pretreatment methods (no pretreatment, multiplicative scatter correction (MSC), standard normal variation (SNV) and 5 points and 3 times smoothing (5-3 smoothing)), four wavelength selection algorithms (successive projection algorithm (SPA), principal component analysis (PCA), X-loading and full-band method) and three different classification modeling methods (partial least squares-discriminant analysis (PLS-DA), K-nearest neighbor (KNN) and support vector machine (SVM)) were applied to make a comparison. Next, the visualization images according to a mean spectrum to mean spectrum (M2M) and a mean spectrum to pixel spectrum (M2P) were compared in order to better represent the freeze damage to the seed embryos. It was concluded that the 5-3 smoothing method and SPA wavelength selection method applied to the modeling can improve the signal-to-noise ratio, classification accuracy of the model (more than 90%). The final classification results of the method M2P were better than the method M2M, which had fewer numbers of misclassified corn seed samples and the samples could be visualized well.

[A retrospective study of the treatment of patients hospitalized for asthma exacerbation in China]

Objective: To study the treatment of patients hospitalized for asthma exacerbation in China. Methods: This was a retrospective study and involved patients hospitalized for asthma exacerbation in 29 hospitals throughout China during Jan 2013 to Dec 2014. Information of the demographic features, the severity of the exacerbation, the medicine prescribed during the hospitalization and the use of mechanical ventilation were collected and analyzed. Results: During the study period, there were 3 240 patients hospitalized for asthma exacerbation, and 1 369(42.3%) of them were males 1 871(57.7%)were females. Patients of mild, moderate, severe, and life-threatening exacerbation counted for 41.7%, 37.8%, 19.2% and 1.0%, respectively of the total patients. Of all the patients, 72.6% used bronchodilators by nebulizer, 70.8% used inhaled corticosteroids by nebulizer, 60.5% used intravenous corticosteroids, 17.3% used oral corticosteroids, and 80.5% used antibiotics. The percentages of patients using systemic corticosteroids and antibiotics were higher in patients with more severe exacerbation. In patients with mild exacerbation, there were 74.9% and 52.2% who used antibiotics and systemic corticosteroids, respectively. A total of 73 patients (2.3%) used mechanical ventilation, and 62 of them used noninvasive ventilation, 16 used invasive ventilation, and 5 used both. Conclusions: Nebulizer therapy has been accepted as the main administration route of medicine in the treatment of asthma exacerbation. A large amount of patients used antibiotics and systemic corticosteroids during hospitalization, indicating there may be some overuse of these medicines.

[Evaluation of asthma disease perception from China national asthma control survey]

Objective: In order to evaluate disease perception of asthma patients in urban China and provide evidence for further specific patient education. Methods: A multi-center, cross-sectional, questionnaire-based survey was carried out in 30 general hospitals dispersed in 30 provinces of mainland China (except for Tibet) during Oct 2015 to May 2016. Information of disease perception [Question 1: the disease nature of asthma; Question 2: medication choice of first-line in chronic asthma; Question 3: the occasion of using short-acting aerosols of receptor agonists; Question 4: perception of asthma treatment goal; Question 5: reason for not using peak flow meter (PFM)] were collected from asthma patients of outpatient department. These results were compared with the same type of survey results from 2007-2008. Results: Altogether 3 875 asthmatic outpatients were recruited. 69.0% (2 660/3 857) of the patients had right perception on the disease nature of asthma, 60.2% (2 321/3 857) of the patients considered inhaled corticosteroids (ICS)/inhaled corticosteroids plus long-acting beta2-agonists (ICS+ LABA) as daily-used first-line medication for chronic asthma. 85.7% (3 277/3 823) of the patients had right perception on the condition of using short-acting beta2-agonists (SABA). 75.4% (2 761/3 661) of the patients had right perception on asthma treatment goal. Only 10.1% (388/3 837) of the patients used PFM. Of the reasons for not using PFM, 65.2% (2 518/3 860) of the patients chose doctors never introduced. Among the 10 cities, which were also involved in the asthma control survey in 2007-2008, 71.1% (968/1 361) of the patients had right perception on the disease nature of asthma, 61.6% (839/1 362) of the patients considered ICS/ICS+ LABA as daily-used first-line medication for chronic asthma. 88.7% (1 207/1 361) of the patients had right perception on the condition of using SABA. 74.5% (1 013/1 360) of the patients had right perception on asthma treatment goal. 17.9% (244/1 360) of the patients used PFM. Of the reasons for not using PFM, 76.2% (931/1 221) of the patients chose doctors never introduced. Compared to the survey conducted in 2007-2008, the perception on disease nature and medication choice as daily-used first-line medication for chronic asthma significantly improved, the perception on occasion of using SABA and asthma treatment goal was comparable, while the rate of PFM usage showed no significant improvement. In reasons of not using PFM, doctors never introduced ranked the first. Conclusions: Compared to the similar survey conducted in 2007-2008, the overall status of disease perception of asthma patients has been improved in urban China, while the rate of PFM usage showed no significant improvement. Asthma education on asthma and asthma self-management should be further pushed forward.

[A retrospective study of the mortality and death-related risk factors of patients hospitalized for asthma exacerbation in Chinese urban areas]

Objective: To study the mortality and death-related risk factors of patients hospitalized for asthma exacerbation in Chinese urban areas. Methods: A retrospective study was carried out in 29 hospitals of 29 provinces throughout mainland China. Patients hospitalized for asthma exacerbation during 2013-2014 in each hospital were included. For each patient, information about demography, admission time, comorbidities, severity of diseases, intense care unit (ICU) admission, use of mechanical ventilation and the outcome was obtained. The mortality of patients hospitalized for asthma exacerbation was calculated, and the basic information and causes of death of the patients who died were summarized. The death-related risk factors and numbers of comorbidities were compared between the patients who survived and those who died during hospitalization. Results: A total of 3 240 patients (median age 57.0) were included and among them 8 patients (median age 68.5) died. The mortality of patients hospitalized for asthma exacerbation was 0.25%. All the patients who died were admitted during the winter and spring. One patient died of acute myocardial infarction, one of cardiac shock, one of tension pneumothorax, one of sudden death, one of respiratory failure and three of unknown causes. The average number of comorbidities of patients who died was 1.10, larger than that of patients who survived (0.83) (P>0.05). More patients had diabetes, coronary artery diseases and hypertension as comorbidities in the patients who died (2/8) than those who survived[7.6% (246/3 232), 7.6% (246/3 232), 22.6% (731/3 232), respectively](all P>0.05). Conclusions: The in-hospital mortality of patients hospitalized for asthma exacerbation of China in this study is low. The patients who died are much older, and with more comorbidities, and a higher percentage of comorbidities such as diabetes, coronary artery diseases, and hypertension.

[A multi-center study for the association between the perception and control of disease among asthmatic patients in Chinese urban areas]

Objective: To investigate the current perception of disease among asthmatic patients in Chinese urban areas, and to address its association with asthma control. Methods: This was a nationwide, multi-center, cross-sectional study covering 30 third-level, grade A hospitals in 30 provinces, municipalities and autonomous regions (not including Tibet) across Chinese mainland. The survey was carried out from October 2015 to May 2016. Asthmatic outpatients were selected to receive face-to-face questionnaire survey on asthma control including Asthma Control Test (ACT) score, classification of asthma control level[according to the Global Initiative for Asthma (GINA) 2015 classification system, as assessed by the physician completing the survey], perception of asthma (including question 1: nature of asthma as a disease; question 2: selection of first-line therapeutic agents to be regularly used daily for asthma; question 3: appropriate timing of the use of short-acting aerosols of β(2) receptor agonists; and question 4: therapeutic goals for asthma). Results: A total of 3 875 asthmatic outpatients were included; among them, 69.0% (2 660/3 857) were aware that asthma is "an airway inflammatory disorder resulting from the combined effects of heredity and environment" ; 60.2% (2 321/3 857) considered "inhaled glucocorticoids or their compound preparations" to be the first-line therapeutic agents to be regularly used daily for patients with persistent chronic asthma; 85.7% (3 277/3 823) considered it appropriate to use short-acting aerosols of β(2) receptor agonists "as needed in the event of disease aggravation or acute exacerbation" ; and 75.4% (2 761/3 661) were aware that asthma "can be adequately or completely controlled in the long term" . The ACT score[20 (16, 23) vs 19 (16, 22) points; Z=-3.928, P<0.001]and asthma control rate (29.92% vs 25.31%; χ(2)=8.616, P=0.003) were significantly higher, and the rate of uncontrolled asthma (19.92% vs 23.48%; χ(2)=6.267, P=0.012) was significantly lower among the 2 660 (69.0%) patients correctly answering question 1 than among the 1 197 (31.0%) patients giving incorrect answer. The ACT score[21 (17, 23) vs 19 (15, 22) points; Z=-9.190, P<0.001] and asthma control rate (32.66% vs 22.20%; χ(2)=49.614, P<0.001) were significantly higher, and the rate of uncontrolled asthma (18.40% vs 25.00%; χ(2)=24.267, P<0.001) was significantly lower among the 2 321 (60.2%) patient correctly answering question 2 than among the 1 536 (39.8%) patients giving incorrect answer. Conclusions: Compared to previous surveys, there has been improved perception of disease among asthmatic patients in Chinese urban areas. Correct perception of disease is favorable for improving asthma control level.

The long-term effects of planting and harvesting on secondary forest dynamics under climate change in northeastern China

Unlike the virgin forest in the Changbaishan Nature Reserve in northeastern China, little research on a landscape scale has been conducted on secondary forests in the region under conditions of a warming climate. This research was undertaken in the upper Hun River region where the vegetation is representative of the typical secondary forest of northeastern China. The spatially explicit forest landscape model LANDIS was utilized to simulate the responses of forest restoration dynamics to anthropogenic disturbance (planting and harvesting) and evaluate the difference of the restoration process under continuation of current climatic conditions and climate warming. The results showed that: (1) The interaction of planting and harvesting has organizational scale effects on the forest. The combination of planting and harvesting policies has significant effects on the overall forest but not on individual species. (2) The area expansion of the historically dominant species Pinus koraiensis is less under climate warming than under continuation of current climatic conditions. These suggests that we should carefully take historically dominant species as the main focus for forest restoration, especially when they are near their natural distribution boundary, because they are probably less capable of successfully adapting to climate change.

Exon-intron circular RNAs regulate transcription in the nucleus

Noncoding RNAs (ncRNAs) have numerous roles in development and disease, and one of the prominent roles is to regulate gene expression. A vast number of circular RNAs (circRNAs) have been identified, and some have been shown to function as microRNA sponges in animal cells. Here, we report a class of circRNAs associated with RNA polymerase II in human cells. In these circRNAs, exons are circularized with introns 'retained' between exons; we term them exon-intron circRNAs or EIciRNAs. EIciRNAs predominantly localize in the nucleus, interact with U1 snRNP and promote transcription of their parental genes. Our findings reveal a new role for circRNAs in regulating gene expression in the nucleus, in which EIciRNAs enhance the expression of their parental genes in cis, and highlight a regulatory strategy for transcriptional control via specific RNA-RNA interaction between U1 snRNA and EIciRNAs.

Estimates of forest biomass carbon storage inLiaoning Province of Northeast China: a review and assessment

Accurate estimates of forest carbon storage and changes in storage capacity are critical for scientific assessment of the effects of forest management on the role of forests as carbon sinks. Up to now, several studies reported forest biomass carbon (FBC) in Liaoning Province based on data from China's Continuous Forest Inventory, however, their accuracy were still not known. This study compared estimates of FBC in Liaoning Province derived from different methods. We found substantial variation in estimates of FBC storage for young and middle-age forests. For provincial forests with high proportions in these age classes, the continuous biomass expansion factor method (CBM) by forest type with age class is more accurate and therefore more appropriate for estimating forest biomass. Based on the above approach designed for this study, forests in Liaoning Province were found to be a carbon sink, with carbon stocks increasing from 63.0 TgC in 1980 to 120.9 TgC in 2010, reflecting an annual increase of 1.9 TgC. The average carbon density of forest biomass in the province has increased from 26.2 Mg ha(-1) in 1980 to 31.0 Mg ha(-1) in 2010. While the largest FBC occurred in middle-age forests, the average carbon density decreased in this age class during these three decades. The increase in forest carbon density resulted primarily from the increased area and carbon storage of mature forests. The relatively long age interval in each age class for slow-growing forest types increased the uncertainty of FBC estimates by CBM-forest type with age class, and further studies should devote more attention to the time span of age classes in establishing biomass expansion factors for use in CBM calculations.

Effects of natural and human-assisted regeneration on landscape dynamics in a Korean pine forest in Northeast China

Improper forest harvesting can potentially degrade forest ecosystem functions and services. Human-assisted regeneration (e.g., planting) is often used to increase the rate of forest recovery and thereby reduce regeneration failure. Seed dispersal is a fundamental ecological process that can also influence spatio-temporal patterns of forest regeneration. In this study, we investigated the relative contribution of planting and seed dispersal on forest regeneration at landscape scales. Because such influences can be further complicated by timber harvest intensity and seed availability within and around harvested area, we also evaluated the effects of those factors on forest landscape dynamics. We used the forest landscape model LANDIS to simulate the dynamics of Korean pine-broadleaf mixed forests in Northeast China. We considered three factors: timber harvest intensity (3 levels), seed dispersal and whether or not planting was used. The results showed that planting was more important in maintaining the abundance of Korean pine (Pinus koraiensis), a climax keystone species in this region, under the high-intensity harvesting option during early succession. In contrast, seed dispersal was more important during late succession. Korean pine can be successfully regenerated through seed dispersal under low and medium harvest intensities. Our results also indicated that effective natural regeneration will require protecting seed-production trees (seed rain). This study results provide a basis for more effectively managing Chinese temperate forests and possibly other similar ecosystems.

An application of remote sensing data in mapping landscape-level forest biomass for monitoring the effectiveness of forest policies in northeastern China

Monitoring the dynamics of forest biomass at various spatial scales is important for better understanding the terrestrial carbon cycle as well as improving the effectiveness of forest policies and forest management activities. In this article, field data and Landsat image data acquired in 1999 and 2007 were utilized to quantify spatiotemporal changes of forest biomass for Dongsheng Forestry Farm in Changbai Mountain region of northeastern China. We found that Landsat TM band 4 and Difference Vegetation Index with a 3 × 3 window size were the best predictors associated with forest biomass estimations in the study area. The inverse regression model with Landsat TM band 4 predictor was found to be the best model. The total forest biomass in the study area decreased slightly from 2.77 × 10(6) Mg in 1999 to 2.73 × 10(6) Mg in 2007, which agreed closely with field-based model estimates. The area of forested land increased from 17.9 × 10(3) ha in 1999 to 18.1 × 10(3) ha in 2007. The stabilization of forest biomass and the slight increase of forested land occurred in the period following implementations of national forest policies in China in 1999. The pattern of changes in both forest biomass and biomass density was altered due to different management regimes adopted in light of those policies. This study reveals the usefulness of the remote sensing-based approach for detecting and monitoring quantitative changes in forest biomass at a landscape scale.

Variation in carbon storage and its distribution by stand age and forest type in boreal and temperate forests in northeastern China

The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and <5%, in boreal and temperate forests respectively, and thus play a minor role in total forest C storage in NE China.

Balancing multiple objectives using a classification-based forest management system in Changbai Mountains, China

Contemporary forest management often consists of multiple objectives, including restoration of human-impacted forested landscapes toward their range of natural variability (RNV) and sustainable levels of timber production. Balancing multiple management objectives is often challenging due to intrinsic conflicts between these objectives and a lack of reference conditions for evaluating the effectiveness of forest restoration efforts. We used a spatially explicit forest landscape model to assess how well a classification-based forest management (CFM) system could achieve multiple objectives in a Korean pine broadleaf mixed forest ecosystem at Changbai Mountain in Northeast China. The CFM system divided the forest landscape into three management areas (Commercial Forest, Special Ecological Welfare Forest, and General Ecological Welfare Forest), each with its own management objectives and prescriptions, but with an overall goal of increasing the ecological and economic sustainability of the entire landscape. The zoning approach adopted in the Chinese CFM system is very similar to the TRIAD approach that is being advocated for managing public forests in Canada. In this study, a natural disturbance scenario and seven harvest scenarios (one identical to the current harvest regime and six alternative scenarios) were simulated to examine how tree species composition, age structure, and timber production at the landscape level can be affected by different strategies under the CFM system. The results indicated that the current forest management regime would not only fail to reach the designated timber production level but also move the forest landscape far away from its RNV. In order to return the currently altered forest landscape to approach its RNV while providing a stable level of timber production over time, harvest intensities should be reduced to a level that is equivalent to the amount of timber removals that would occur under the natural disturbances; and the establishment of forest plantations is also required.

Application of China's National Forest Continuous Inventory database

The maintenance of a timely, reliable and accurate spatial database on current forest ecosystem conditions and changes is essential to characterize and assess forest resources and support sustainable forest management. Information for such a database can be obtained only through a continuous forest inventory. The National Forest Continuous Inventory (NFCI) is the first level of China's three-tiered inventory system. The NFCI is administered by the State Forestry Administration; data are acquired by five inventory institutions around the country. Several important components of the database include land type, forest classification and ageclass/ age-group. The NFCI database in China is constructed based on 5-year inventory periods, resulting in some of the data not being timely when reports are issued. To address this problem, a forest growth simulation model has been developed to update the database for years between the periodic inventories. In order to aid in forest plan design and management, a three-dimensional virtual reality system of forest landscapes for selected units in the database (compartment or sub-compartment) has also been developed based on Virtual Reality Modeling Language. In addition, a transparent internet publishing system for a spatial database based on open source WebGIS (UMN Map Server) has been designed and utilized to enhance public understanding and encourage free participation of interested parties in the development, implementation, and planning of sustainable forest management.

Forest management in Northeast China: history, problems, and challenges

Studies of the history and current status of forest resources in Northeast China have become important in discussions of sustainable forest management in the region. Prior to 1998, excessive logging and neglected cultivation led to a series of problems that left exploitable forest reserves in the region almost exhausted. A substantial decrease in the area of natural forests was accompanied by severe disruption of stand structure and serious degradation of overall forest quality and function. In 1998, China shifted the primary focus of forest management in the country from wood production to ecological sustainability, adopting ecological restoration and protection as key foci of management. In the process, China launched the Natural Forest Conversion Program and implemented a new system of Classification-based Forest Management. Since then, timber harvesting levels in Northeast China have decreased, and forest area and stocking levels have slowly increased. At present, the large area of low quality secondary forest lands, along with high levels of timber production, present researchers and government agencies in China with major challenges in deciding on management models and strategies that will best protect, restore and manage so large an area of secondary forest lands. This paper synthesizes information from a number of sources on forest area, stand characteristics and stocking levels, and forest policy changes in Northeastern China. Following a brief historical overview of forest harvesting and ecological research in Northeast China, the paper discusses the current state of forest resources and related problems in forest management in the region, concluding with key challenges in need of attention in order to meet the demands for multi-purpose forest sustainability and management in the future.

Major forest types and the evolution of sustainable forestry in China

In this article, we introduce China's major forest types and discuss the historical development of forest management in China, including actions taken over the last decade toward achieving SMF. Major challenges are identified, and a strategy for SFM implementation in China is presented. China's forests consist of a wide variety of types with distinctive distributional patterns shaped by complex topography and multiple climate regimes. How to manage this wide array of forest resources has challenged forest managers and policy-makers since the founding of the country. Excessive exploitation of China's forest resources from the 1950s to the late 1990s contributed to environmental problems and calamities, such as floods, soil erosion, and desertification. At the start of the new millennium, the Chinese government decided to shift its emphasis from timber production towards the achievement of sustainable forest management (SFM). With a series of endeavors such as the implementation of the "Six Key Forestry Projects" and the reform of forest tenure policies, and the adoption of a classification system for China's forests, a beginning has been made at reversing the trend of environmental degradation that occurred throughout the latter half of the last century. At the same time, huge challenges remain to be tackled for the development of forestry in China.

[Effects of altitudinal gradient on water use efficiency of Betula ermanii on the northern slope of Changbai Mountains, northeast China]

Taking Betula ermanii forests distributed at the altitudes 1800-2050 m on the northern slope of Changbai Mountains as test objects, and using leaf carbon isotope content (813 C) as an indicator of B. ermanii water use efficiency (WUE), this paper studied the effects of altitudinal gradient on the WUE of B. ermanji forests in the area. With the increase of altitude, the soil volumetric water content (VMC) and the leaf mass per area (LMA) of B. ermanji increased significantly, while the leaf water content (LWC) and soil temperature were in adverse. There was a significant positive correlation between leaf delta13 C and altitude, with the increment of leaf delta13 C being 1.013 % per hundred x (100 m)(-1), and the leaf delta13C was positively correlated with soil VWC and LMA but negatively correlated with soil temperature and LWC. Temperature was not the sole limiting factor for the distribution of treeline in Changbai Mountains, whereas the physiological drought of B. ermanii during its growing season caused by the different water and heat conditions and their interactions along the altitudinal gradient could be the other limiting factors.

[Carbon storage, density, and distribution in forest ecosystems in Jilin Province of northeast China]

By using forest resources inventory data and field investigation data, this paper studied the carbon storage, density, and distribution characteristics in forest ecosystems in Jilin Province of Northeast China. The total carbon storage in the forest ecosystems was 1827.293 Tg C, and the carbon storages in arbor layer, shrub-grass layer, litter layer, and soil were 439.152 Tg C, 5.195 Tg C, 45.600 Tg C, and 1330.466 Tg C, accounting for 24.1%, 0.3%, 2.5%, and 73.1% of the total, respectively. The carbon density in the forest ecosystems was 225.304 Mg C x hm(-2), with 54.352 Mg C x hm(-2) in arbor layer, 0.643 Mg C x hm(-2) in shrub-grass layer, 5.644 Mg C x hm(-2) in litter layer, and 164.666 Mg C x hm(-2) in soil. Different types of the forest ecosystems had a carbon storage varied from 9.357 Tg C to 959.716 Tg C and a carbon density ranged from 180.648 Mg C * hm(-2) to 254.627 Mg C x hm(-2), with the highest values in soil and the lowest values in shrub-grass layer. Overall, the carbon storage and density in the forest ecosystems were greater in eastern mountainous area than in central and western plains. In the Province, middle-aged forests had a greater proportion than the forests in other age classes, and thereby, a proper management of the present forests could increase the carbon sequestration of the forest ecosystems.

Effects of external electric field on film growth, morphology, and nanostructure of polyelectrolyte and nanohybrid multilayers onto insulating substrates

Electric-field-enhanced layer-by-layer (LbL) assembly of polyelectrolyte and nanohybrid multilayers onto insulating rigid substrates was successfully accomplished using two independent capacitor cells. The influence of external electric field on the multilayer formation was intensively investigated by UV-vis adsorption spectrometry, profilometry, atomic force microscopy, and small-angle X-ray diffraction. This approach was also attempted as a means of fabricating selective layer on flat sheet polymeric porous substrates to obtain the dense composite membranes with high pervaporation performance.

[Research progress in water use efficiency of plants under global climate change]

Global climate change is one of the most concerned environmental problems in the world since the 1980s, giving significant effects on the plant productivity and the water transport and use patterns. These effects would be reflected in the water use efficiency (WUE) of individual plants, communities, and ecosystems, and ultimately, in the vegetation distribution pattern, species composition, and ecosystem structure. To study the WUE of plants would help to the understanding and forecasting of the responses of terrestrial vegetation to global climate change, and to the adoption of adaptive strategies. This paper introduced the concept of plant WUE and the corresponding measurement techniques at the scales of leaf, individual plant, community, and ecosystem, and reviewed the research progress in the effects of important climatic factors such as elevated atmospheric CO2 concentration, precipitation pattern, nitrogen deposition, and their combination on the plant WUE, as well as the variation characteristics of plant WUE and the adaptive survival strategies of plants under different site conditions. Some problems related to plant WUE research were pointed out, and the future research directions in the context of global climate change were prospected.

[Dynamic changes of forest landscape pattern in Lushuihe Forest Bureau of Changbai Mountains, northeast China]

Based on the forest management inventories in Lushihe Forest Bureau of Changbai Mountains in 1987, 1995 and 2003, and by using ArcGIS and Fragstats spatial analysis software, this paper analyzed the relationships between landscape pattern change and forest management mechanism in the study area at landscape and patch scales. During the study period, the landscape fragmentation degree and heterogeneity in the study area increased. From 1987 to 2003, the patch number increased by 979, while the proportion of the largest patch area decreased from 28. 7% to 12.7%. With the change of management strategy, the landscape matrix changed from mixed broad-leaved forest matrix in 1987 to compound matrix in 1995. The extent of landscape fragmentation in 1995-2003 was somewhat reduced, compared with that in 1987-1995. During the study period, the mean patch area and edge density of broadleaved mixed forest decreased most, suggesting that natural secondary forest suffered most from human disturbances.

China's classification-based forest management: procedures, problems, and prospects

China's new Classification-Based Forest Management (CFM) is a two-class system, including Commodity Forest (CoF) and Ecological Welfare Forest (EWF) lands, so named according to differences in their distinct functions and services. The purposes of CFM are to improve forestry economic systems, strengthen resource management in a market economy, ease the conflicts between wood demands and public welfare, and meet the diversified needs for forest services in China. The formative process of China's CFM has involved a series of trials and revisions. China's central government accelerated the reform of CFM in the year 2000 and completed the final version in 2003. CFM was implemented at the provincial level with the aid of subsidies from the central government. About a quarter of the forestland in China was approved as National EWF lands by the State Forestry Administration in 2006 and 2007. Logging is prohibited on National EWF lands, and their landowners or managers receive subsidies of about 70 RMB (US$10) per hectare from the central government. CFM represents a new forestry strategy in China and its implementation inevitably faces challenges in promoting the understanding of forest ecological services, generalizing nationwide criteria for identifying EWF and CoF lands, setting up forest-specific compensation mechanisms for ecological benefits, enhancing the knowledge of administrators and the general public about CFM, and sustaining EWF lands under China's current forestland tenure system. CFM does, however, offer a viable pathway toward sustainable forest management in China.

China's classification-based forest management: procedures, problems, and prospects

China's new Classification-Based Forest Management (CFM) is a two-class system, including Commodity Forest (CoF) and Ecological Welfare Forest (EWF) lands, so named according to differences in their distinct functions and services. The purposes of CFM are to improve forestry economic systems, strengthen resource management in a market economy, ease the conflicts between wood demands and public welfare, and meet the diversified needs for forest services in China. The formative process of China's CFM has involved a series of trials and revisions. China's central government accelerated the reform of CFM in the year 2000 and completed the final version in 2003. CFM was implemented at the provincial level with the aid of subsidies from the central government. About a quarter of the forestland in China was approved as National EWF lands by the State Forestry Administration in 2006 and 2007. Logging is prohibited on National EWF lands, and their landowners or managers receive subsidies of about 70 RMB (US$10) per hectare from the central government. CFM represents a new forestry strategy in China and its implementation inevitably faces challenges in promoting the understanding of forest ecological services, generalizing nationwide criteria for identifying EWF and CoF lands, setting up forest-specific compensation mechanisms for ecological benefits, enhancing the knowledge of administrators and the general public about CFM, and sustaining EWF lands under China's current forestland tenure system. CFM does, however, offer a viable pathway toward sustainable forest management in China.

[Ecological classification system of forest landscape in eastern mountainous region of Liaoning Province]

Based on Digital Elevation Models (DEM) and satellite SPOT-5 data, and by using the spatial analysis function in Geographic Information System, a hierachical Ecological Classification System of forest landscape was developed for the eastern mountainous region of Liaoning Province, and the two lowest layers in the hierachical framework, Ecological Land Types (ELTs) and Ecological Land Type Phases (ELTPs), were mapped. The results indicated that there were 5 ELTs and 34 ELTPs. The boundaries of ELTs, which presented the potential vegetation distribution and potential forestry ecosystem productivity, were determined by environmental conditions quantified by DEM. ELTPs were classified by overlaying ELTs with forest vegetation data layers which were obtained from remotely sensed data, forest inventory data, and ground data. The ELTPs represented the divisions of land in terms of both natural and human-induced forest conditions, and therefore, were reliable units for forest inventories and management. ELTPs could function as conventional forest inventory sub-compartments. By this means, forestry departments could adjust forest management planning and forest management measures from the viewpoint of forest landscape scale to realize forest ecosystem management.

[Relationship between tree-ring chronology of Larix olgensis in Changbai Mountains and the climate change]

The relationship of larch (Larix olgensis) radial growth in Changbai Mountains with climate change was assessed by dendrochronological techniques including correlation functions and single-years analysis. The results showed that larch growth was sensitive to environmental change, and temperature was the primary factor affecting larch growth. The larch growing in high and low elevations had a significantly different response to temperature. In high elevation, larch growth was significant correlated to the mean temperature of June, but in low elevation, it had a more complicated relationship to the environment. Besides the mean temperature of April and May, the temperature of last June and September and the humid index of last September significantly correlated with the larch tree ring-width. Therefore, it was not the same relationship of the same tree species with different environmental gradients.

[Assessing forest ecosystem health II. A case study]

On the bases of samples investment and related data collected by others, and with the method of health distance assessment and the ecosystem health index system of Korean pine and broad-leaved mixed forest established in prior paper, this paper attempted to assess the ecosystem health of Korean pine and broad-leaved mixed forest under various human disturbances. The results showed that the health degree was in the order of 20% intensity selective cutting stand (0.21) < 50% intensity selective cutting stand (0.44) < middle and mature birch stand (0.67) < youth birch stand (0.72) < Korean pine plantation (0.74) < larch plantation (0.77).

[Structure characteristics and health distance assessment of various disturbed communities of Korean pine and broadleaved mixed forest in Changbai Mountains]

Through samples investigation, this paper analyzed and classified the community structures of overcutting original forests, secondary birch forests and larch plantation forest under different disturbances. At the same time, some indexes which can reflect the integrity and stability of stand structure were selected. Health Distance (HD) method, a new idea, was attempted to assess ecosystem health of Korean pine and broadleaved mixed forest in Changbai Mountains. The results showed that the health degree was in order of original broadleaved stand (0.14) < structure switched stand (0.23) < structure reserved stand (0.32) < structure destroyed stand (0.33) < heavy disturbed stand (0. 44) < secondary birch stand (0.53) < larch plantations (0.68). Hopefully, it will be a helpful reference on the restoration of Korean pine and broadleaved mixed forest and on the regional forestry sustainable development.

[Quantitative methodologies for ecotone determination on north slope of Changbai Mountains]

Based on the community important values and present-absent data along elevation gradient on the north slope of Changbai Mountains and using moving split-window techniques, the width and location of vegetation ecotone were discussed in this article. The results showed that the methods of Bray-Curtis Percent Dissimilarity (PD) and Squared Euclidean Distance (SED) introduced in the analysis gave the similar results. Among the methods used in the moving split-window analysis, the SED method was the best in showing the variation of ecotone. According to the results of moving split-window techniques analysis, the ecotone between broad leaved-pine forest and dark conifer forest was gradual type, located in 1120 m a.s.l., spanned 200 m.; that between dark conifer forest and Betula ermanii forest was sharp type, located in 1790 m a.s.l., spanned 50 m; and the timberline was a sharp line, located in 2000 m, spanned 40 m.